JP2015176038A - toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a toner that can inhibit problems such as toner scattering while maintaining storage property in a color image forming apparatus achieving fast image formation and a compact apparatus.SOLUTION: The toner is used in an image forming apparatus that includes an electrostatic latent image carrier, charging means for charging a surface of the electrostatic latent image carrier, exposure means for exposing the charged electrostatic latent image carrier to form an electrostatic latent image, and developing means for developing the electrostatic latent image by use of a toner to form a visible image. The image forming apparatus satisfies a relationship of 2.2≤A/B≤2.6, where A [mm/sec] represents a line velocity of a developing roller in the developing means and B [g] represents a developer volume in the developing means. The toner contains hydrophobic silica particles as an external additive. An isolation rate of the hydrophobic silica particles in the toner is 3 to 15 mass%.

Description

  The present invention relates to a toner used as a developer for developing an electrostatic image in electrophotography, electrostatic recording, electrostatic printing, and the like, a developer using the toner, and an image forming method.

  In recent years, in the field of electrophotographic image forming technology, organic / inorganic fine particles that impart fluidity are externally added to a toner base generally composed of resin in order to supplement transportability and mixing properties. ing. However, the organic / inorganic fine particles added externally to the toner in order to impart fluidity are embedded in the toner due to stress with the member that comes into contact with the toner during use, and the fluidity is impaired. And chargeability deteriorated. In addition, in a toner that is not sufficiently mixed, the organic / inorganic fine particles are released from the toner particles and float in the image forming apparatus to contaminate the inside of the apparatus, or adhere to an image carrier such as a photoreceptor. There is a problem that filming of an external additive that becomes a base point to which the toner is fixed occurs.

  In order to solve the above-mentioned problem, as a technique related to the free amount of the external additive, for example, in Patent Document 1, in order to suppress the occurrence of filming and improve the cleaning property, the external additive is added to 100 parts by mass of the toner. A toner having a free amount of 0.1 to 1.0 parts by mass is disclosed. Patent Document 2 discloses a toner in which the liberation rate of hydrophobic silica in the toner is 1% by mass to 20% by mass and the liberation rate of fatty acid metal salt particles is 30% by mass to 90% by mass. Yes.

  Further, as a technique relating to the external additive used, in order to maintain excellent cleaning properties over a long period of time, the volume average particle diameter is 70 nm or more and 400 nm or less, and the volume average with respect to the standard deviation σ of the volume-based particle diameter A toner having an external additive having a particle size ratio (d / σ) of 2.0 to 12 and an average circularity of 0.5 to 0.9 is disclosed.

  However, at present, in the electrophotographic image forming technology field, competition for development of a color image forming apparatus which can form a high-speed and high-quality image and is compact as an apparatus is intensifying. In such a color image forming apparatus that achieves both high-speed image formation and compactness, the developer capacity in the unit tends to be smaller than the linear speed of the developing roller in the developing machine. Therefore, the stress applied to the developer due to the stirring of the developer becomes very large, the release of the organic / inorganic fine particles from the toner is accelerated, and the carrier is contaminated, thereby causing problems such as toner scattering. is there.

  The present invention has been made in view of the above problems, and in a color image forming apparatus that achieves both high-speed image formation and compactness, it is possible to suppress problems such as toner scattering while maintaining storability. The problem is to provide toner.

As means for solving the above problems, the present invention has the following features. That is,
<1> An electrostatic latent image carrier, a charging unit that charges the surface of the electrostatic latent image carrier, an exposure unit that exposes the charged electrostatic latent image carrier to form an electrostatic latent image, A toner used in an image forming apparatus having a developing unit that develops an electrostatic latent image with toner to form a visible image,
In the image forming apparatus, the linear velocity of the developing roller in the developing unit is A [mm / sec],
When the developer capacity in the developing means is B [g], A and B satisfy the following relational expression (1):
2.2 ≦ A / B ≦ 2.6 (1)
The toner has hydrophobic silica particles as an external additive, and the liberation rate of the hydrophobic silica particles in the toner is 3 to 15% by mass.

  As described above, according to the means for solving the above problem, in the image forming apparatus of the present invention, even in a color image forming apparatus that achieves both high-speed image formation and compactness, toner splattering and the like are maintained while maintaining storability. Therefore, it is possible to provide a toner capable of suppressing this problem.

3 is a diagram illustrating an example of a roller charging unit in the image forming apparatus of the present invention. FIG. FIG. 3 is a diagram illustrating an example of a brush charging unit in the image forming apparatus of the present invention. FIG. 4 is a diagram illustrating an example of a developing unit in the image forming apparatus of the present invention. FIG. 3 is a diagram illustrating an example of a fixing unit in the image forming apparatus of the present invention. FIG. 3 is a diagram illustrating an example of a layer configuration of a fixing belt as a fixing unit. 1 is a schematic diagram illustrating an example of an image forming apparatus of the present invention. It is the schematic which shows another example of the image forming apparatus of this invention. It is the schematic which shows an example of a process cartridge. It is a figure which shows a belt fixing device.

  EMBODIMENT OF THE INVENTION Below, the form for implementing this invention is demonstrated based on drawing. Note that it is easy for a person skilled in the art to make other embodiments by changing or correcting the present invention within the scope of the claims, and these changes and modifications are included in the scope of the claims, The following description is an example of the best mode of the present invention, and does not limit the scope of the claims.

(toner)
The toner of the present invention contains toner base particles and an external additive, and further contains other components as necessary.

<External additive>
The external additive contains at least inorganic fine particles.
In the present invention, the inorganic fine particles include at least hydrophobic silica particles, and the liberation rate of the hydrophobic silica particles from the toner is 3 to 15% by mass, and preferably 5 to 11% by mass.

The hydrophobic silica particles are externally added to the toner base particles mainly to obtain chargeability and toner fluidity. The separation of the hydrophobic silica particles from the toner not only impairs the chargeability and fluidity of the toner, but also adversely affects toner scattering, fogging, and the like. Filming is caused by scratching. For this reason, it is necessary not to release the hydrophobic silica particles from the toner as much as possible.
However, from the viewpoint of toner fluidity and the like, the liberation rate of the hydrophobic silica particles need not be 0 (zero) mass%, but rather 3 mass% or more is necessary. On the other hand, in the image forming apparatus, the developing roller linear velocity A [mm / sec] in the developing machine and the developer capacity B [g] in the unit are in the range of 2.2 ≦ A / B ≦ 2.6. When the apparatus is used, if the liberation rate of the hydrophobic silica particles exceeds 15% by mass, the hydrophobic silica particles are released from the toner and adhere to the carrier, and the developer is remarkably charged. Since the reduction occurs and the toner scatters, it is necessary to be 15% by mass or less.

  Further, when the primary particle size of the inorganic fine particles released in the developer is reduced, the inorganic fine particles adhere to cover a carrier or the like. For this reason, it is considered that the charging ability of the carrier is easily deteriorated and the toner scattering is likely to occur. Therefore, it is desirable that the particle size of the released inorganic fine particles is 10 nm or more. Further, when the particle size of the released inorganic fine particles is 2 μm or more, it is considered that the inorganic fine particles are aggregated, and there is a concern that the fixing of the developer may be adversely affected.

  Further, it has been confirmed that when the circularity of the free inorganic fine particles decreases, the amount of the inorganic fine particles attached to the carrier decreases, and toner scattering hardly occurs. The cause is unknown, but it is considered that the irregularly shaped inorganic fine particles are more difficult to be scraped by contact with the carrier and have the effect of scraping out the inorganic fine particles attached to the carrier.

Here, the liberation rate of the hydrophobic silica particles can be measured, for example, as follows.
(1) To 200 mL ointment bottle, add 100 mL of ion-exchanged water and 4.4 mL of 33% by mass of a dry well aqueous solution (trade name: Drywell, manufactured by Fuji Film Co., Ltd.) containing surfactant, and mix well. Then, add 5 g of toner to the resulting mixture, mix well by hand shaking 30 times, and let stand for 1 hour or more.
(2) Next, after stirring by hand shaking 20 times, using an ultrasonic homogenizer (trade name: homogenizer, model VCX750, CV33, manufactured by SONICS & MATERIALS Co., Ltd.), a dial is set at an output of 50% for 1 minute under the following conditions. Apply ultrasonic energy and disperse.
-Ultrasonic conditions-
・ Vibration time: 60 seconds continuous ・ Amplitude: 20 W (30%)
・ Vibration start temperature: 23 ℃ ± 1.5 ℃
(3) The obtained dispersion is centrifuged for 2 minutes at 2000 rpm with a centrifuge (product name: desktop multi-centrifuge H-40F, manufactured by KOKUSAN), and the supernatant is discarded.
(4) The obtained solid content is again dispersed in 60 ml of ion exchange water, suction filtered with a filter paper (trade name: qualitative filter paper (No. 2, 110 mm), manufactured by Advantech Toyo Co., Ltd.), and again 2 with ion exchange water. The toner was dried after washing twice, filtering, removing the free external additive.
(5) The amount of the external additive of the toner before and after the removal of the external additive was quantified by a fluorescent X-ray method (ZSX-100e, manufactured by Rigaku Corporation) to determine the free amount of the external additive.
In the fluorescent X-ray method, the amount of free hydrophobic silica particles was determined by measuring Si.

From the value of the external additive amount of the toner before and after the dispersion measured by the methods (1) to (5), the liberation rate (% by mass) of the external additive was obtained by the following (Formula 1). .
(Formula 1)
Release rate = [(mass of external additive before dispersion−mass of residual additive after dispersion) / mass of external additive before dispersion] × 100

The method for adjusting the liberation rate of the hydrophobic silica particles to the above numerical range is not particularly limited and can be appropriately selected according to the purpose. For example, the amount and type of the hydrophobic silica particles are adjusted. And a method of adjusting conditions at the time of mixing external additives. Among these, the method of adjusting the mixing conditions at the time of external addition is particularly preferable.
As the mixing condition of the external additive, the target value is obtained by adjusting the order of mixing the organic / inorganic fine particles, the number of rotations of the high-speed flow mixer, the mixing time, the temperature in the tank, and the like. be able to.
Examples of the high-speed fluid mixer include a Henschel mixer (Henschel 20B, manufactured by Mitsui Mining Co., Ltd.), a super mixer (Kawata Co., SMV-20A), and the like.

<< Inorganic fine particles >>
The inorganic fine particles can be suitably used as an external additive for improving the fluidity, developability, chargeability and the like of the toner. The inorganic fine particles are preferably the same type as the inorganic fine particles that can be dispersed in the organic solvent.

There is no restriction | limiting in particular as said inorganic fine particle, According to the objective, it can select from well-known things suitably.
For example, silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, tin oxide, silica sand, clay, mica, wollastonite, diatomaceous earth, chromium oxide, cerium oxide , Pengala, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, silicon nitride, and the like. These may be used individually by 1 type and may use 2 or more types together. Among these, silica particles and titanium oxide particles are preferable, and two or more types of silica particles and titanium oxide particles having different primary average particle diameters are particularly preferable.

The primary particle diameter of the inorganic fine particles is preferably 5 nm to 2 μm, and more preferably 5 nm to 500 nm. The specific surface area of the inorganic fine particles by BET method is preferably 20 to 500 m ² / g.
The content of the inorganic fine particles in the toner is preferably 0.01 to 5.0% by mass, and more preferably 2.0 to 4.5% by mass.

  The primary average particle size of the inorganic fine particles was measured by dispersing a primary particle in a solvent (tetrahydrofuran (THF)), and then removing the solvent on the substrate to dry the sample, using a field emission scanning electron microscope ( FE-SEM, acceleration voltage: 0.5 kV to 1 kV, observation magnification: 50,000 times to 100,000 times, the average value of the particle diameter of the external additive in the visual field was measured (measured number of particles: 100) ).

The inorganic fine particles are preferably surface-treated with a fluidity improver. Thereby, the hydrophobicity of the inorganic fine particles is improved, and the decrease in fluidity and chargeability can be suppressed even under high humidity.
Examples of the fluidity improver include, for example, a silane coupling agent, a silylating agent, a silane coupling agent having a fluorinated alkyl group, an organic titanate coupling agent, an aluminum coupling agent, silicone oil, and modified silicone oil. Etc.
Silica and titanium oxide as the inorganic fine particles are preferably surface-treated with the fluidity improver and used as hydrophobic silica particles and hydrophobic titanium oxide particles.

The coverage of the inorganic fine particles on the toner is preferably 50% to 85%, more preferably 60% to 80%. When the coverage is less than 50%, the influence of the toner base particles is increased, and the toner may be fixed. When the coverage is more than 85%, the external additive has almost a large surface, and the surface becomes a photosensitive member. In some cases, scratches may occur, the photoconductor may be scraped off, and low-temperature fixability cannot be maintained.
Here, the coverage of the toner base particles with the inorganic fine particles can be calculated by, for example, the following equation.
H = Σ (√3 × Dv × Pt / (2π · da · Pa) × Ca × 100)
In the above formula, Dv is the volume average particle diameter of the toner base particles, Pt is the true specific gravity of the toner base particles, da is the primary average particle diameter of the external additive, Pa is the true specific gravity of the external additive, and Ca is in the toner. This represents the content (%) of the external additive.
When there are a plurality of external additives, the primary average particle diameter da, the true specific gravity Pa, and the content Ca are obtained for each external additive, the individual coverage is calculated, and these are totaled. The overall coverage can be determined.

The volume average particle diameter of the toner base particles can be measured using, for example, Coulter Multisizer III (manufactured by Coulter Inc.).
The measurement of the primary average particle diameter of the external additive is as described above.
The true specific gravity of the toner base particles and the external additive was measured in accordance with JISK-0061: 92, 5-2-1, using a Le Chatelier specific gravity bottle.
In the measurement of the liberation rate, the particle size of the liberated external additive (particles) is preferably adjusted to 10 nm or more and 2 μm or less. The average degree of circularity of the liberated external additive is preferably adjusted in the range of 0.5 to 0.9.

<Toner base particles>
The toner base particles contain at least a binder resin and a colorant, and further contain other components as necessary.
The binder resin includes an amorphous resin and a crystalline resin.

<< Amorphous resin >>
The amorphous resin is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include a polyester resin, and particularly glossiness when used in a low-temperature fixability and full-color image forming apparatus. An unmodified polyester resin (an unmodified polyester resin) is preferable in terms of improving the properties.
The amorphous polyester preferably contains an unmodified polyester resin (unmodified polyester) or a modified polyester.

―Unmodified polyester―
It is preferable that 45 mol%-55 mol% of the unmodified polyester resin is an alcohol component, and 45 mol%-55 mol% is an acid component.
Examples of the alcohol component include ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, diethylene glycol, triethylene glycol, 1,5-pentanediol, 1, Diols such as 6-hexanediol, neopentyl glycol, 2-ethyl-1,3-hexanediol, hydrogenated bisphenol A, bisphenol derivatives (for example, bisphenol A ethylene oxide adduct, bisphenol A propylene oxide adduct, etc.), etc. Is mentioned.

As said acid component, it is preferable that 50 mol% or more of bivalent carboxylic acid is included in all the acid components.
Examples of the divalent carboxylic acid include benzene dicarboxylic acids such as phthalic acid, terephthalic acid, isophthalic acid, and phthalic anhydride or anhydrides thereof; alkyl dicarboxylic acids such as succinic acid, adipic acid, sebacic acid, and azelaic acid; Examples thereof include anhydrides thereof, succinic acids substituted with alkyl groups or alkenyl groups having 6 to 18 carbon atoms, or anhydrides thereof; unsaturated dicarboxylic acids such as fumaric acid, maleic acid, citraconic acid, and itaconic acid; and anhydrides thereof. It is done.
Among these, the alcohol component is preferably a bisphenol derivative, and the acid component is phthalic acid, terephthalic acid, isophthalic acid or its anhydride, succinic acid, N-dodecenyl succinic acid, or its anhydride, fumaric acid, maleic acid. Dicarboxylic acids such as acid and maleic anhydride are preferred.

  The weight average molecular weight (Mw) measured by a gel permeation chromatograph (GPC) of the unmodified polyester resin soluble in tetrahydrofuran (THF) is not particularly limited and may be appropriately selected depending on the intended purpose. However, it is preferably 1,000 to 20,000, and more preferably 2,000 to 10,000.

  The number average molecular weight (Mn) measured by gel permeation chromatography (GPC) of the tetrahydrofuran (THF) soluble portion of the unmodified polyester resin is not particularly limited and may be appropriately selected depending on the purpose. For example, 500 to 6,000 is preferable, and 1,000 to 5,000 is more preferable.

  The ratio (Mw / Mn) of the number average molecular weight Mn to the weight average molecular weight Mw of the unmodified polyester resin is preferably 4 or less, and more preferably 2-4. If the Mw / Mn exceeds 4, the elasticity during fixing is large and the low-temperature fixability may be impaired. If the Mw / Mn is less than 2, the heat resistant storage stability of the toner is inhibited and the heat is discharged from the paper. The elastic recovery is small, and the paper discharge resistance may be insufficient.

The glass transition temperature of the unmodified polyester resin is preferably 30 ° C to 60 ° C.
The glass transition temperature of the unmodified polyester resin can be measured by, for example, a DSC curve obtained by differential scanning calorimetry (DSC).
The unmodified polyester resin preferably has an acid value of 1 mgKOH / g to 50 mgKOH / g.
The acid value can be measured according to a measurement method described in JIS K0070-1992.

-Modified polyester resin-
By using the modified polyester resin, the toner can have an appropriate cross-linked structure. The modified polyester resin is not particularly limited as long as it is a resin having at least one of a urethane bond and a urea bond, and can be appropriately selected according to the purpose. The active hydrogen group-containing compound and the active hydrogen A resin obtained by subjecting a binder resin precursor having a functional group capable of reacting with a group-containing compound (hereinafter sometimes referred to as “prepolymer”) to an extension reaction and / or a crosslinking reaction is preferable.

The prepolymer is not particularly limited as long as it is a polyester resin having at least a functional group capable of reacting with the active hydrogen group-containing compound, and can be appropriately selected according to the purpose.
The functional group capable of reacting with the active hydrogen group in the prepolymer is not particularly limited and may be appropriately selected from known substituents, such as isocyanate groups, epoxy groups, carboxylic acids, and acid chlorides. Group and the like. These may be contained singly or in combination of two or more. Among these, an isocyanate group is preferable.

  The method for synthesizing the prepolymer is not particularly limited and may be appropriately selected depending on the purpose. For example, in the case of an isocyanate group-containing prepolymer, a polyol and a polycarboxylic acid are mixed with a known esterification catalyst (for example, In the presence of titanium tetrabutoxide, dibutyltin oxide, etc.), heated to 150 ° C. to 280 ° C. and appropriately reduced pressure as necessary, distilled off water to obtain a hydroxyl group-containing polyester, and then 40 ° C. to 140 ° C. And a method of synthesizing the hydroxyl group-containing polyester by reacting with a polyisocyanate.

  There is no restriction | limiting in particular as said polyol, According to the objective, it can select suitably, For example, alkylene glycol (For example, ethylene glycol, 1, 2- propylene glycol, 1, 3- propylene glycol, 1, 4- butane) Diol, 1,6-hexanediol, etc.), alkylene ether glycol (eg, diethylene glycol, triethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, etc.), alicyclic diol (eg, 1, 4-cyclohexanedimethanol, hydrogenated bisphenol A, etc.), bisphenols (eg, bisphenol A, bisphenol F, bisphenol S, etc.), alkylene oxides of the alicyclic diols (examples) Diols such as ethylene oxide, propylene oxide, butylene oxide, etc.) adducts, alkylene oxide (eg, ethylene oxide, propylene oxide, butylene oxide etc.) adducts of the bisphenols; polyhydric aliphatic alcohols (eg, glycerin, Trimethylolethane, trimethylolpropane, pentaerythritol, sorbitol, etc.), trivalent or higher phenols (for example, phenol novolak, cresol novolak, etc.), trivalent or higher polyols such as alkylene oxide adducts of trivalent or higher polyphenols. A mixture of a diol and a trihydric or higher polyol; These may be used individually by 1 type and may use 2 or more types together.

  Among these, the polyol is preferably the diol alone or a mixture of the diol and a small amount of the trivalent or higher polyol. Examples of the diol include alkylene glycols having 2 to 12 carbon atoms and alkylene oxide adducts of bisphenols (for example, bisphenol A ethylene oxide 2 mol adduct, bisphenol A propylene oxide 2 mol adduct, bisphenol A propylene oxide 3 mol adduct). Etc.) is preferred.

  There is no restriction | limiting in particular as said polycarboxylic acid, According to the objective, it can select suitably, For example, alkylene dicarboxylic acid (For example, succinic acid, adipic acid, sebacic acid, etc.); Alkenylene dicarboxylic acid (for example, maleic acid) Aromatic dicarboxylic acids (eg, terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, etc.); trivalent or higher polycarboxylic acids (eg, trimellitic acid, pyromellitic acid, etc. having 9 to 20 carbon atoms) Aromatic polycarboxylic acid and the like). These may be used individually by 1 type and may use 2 or more types together.

Among these, the polycarboxylic acid is preferably an alkenylene dicarboxylic acid having 4 to 20 carbon atoms and an aromatic dicarboxylic acid having 8 to 20 carbon atoms.
In place of the polycarboxylic acid, an anhydride of polycarboxylic acid, a lower alkyl ester (for example, methyl ester, ethyl ester, isopropyl ester, etc.) can be used.

  The mixing ratio of the polyol and the polycarboxylic acid is not particularly limited and may be appropriately selected depending on the intended purpose. The mixing ratio between the hydroxyl group [OH] of the polyol and the carboxyl group [COOH] of the polycarboxylic acid is not limited. The equivalent ratio [OH] / [COOH] is preferably 2/1 to 1/1, more preferably 1.5 / 1 to 1/1, and particularly preferably 1.3 / 1 to 1.02 / 1.

  There is no restriction | limiting in particular as said polyisocyanate, According to the objective, it can select suitably, For example, aliphatic polyisocyanate (For example, tetramethylene diisocyanate, hexamethylene diisocyanate, 2, 6- diisocyanatomethyl caproate, Octamethylene diisocyanate, decamethylene diisocyanate, dodecamethylene diisocyanate, tetradecamethylene diisocyanate, trimethylhexane diisocyanate, tetramethylhexane diisocyanate, etc .; alicyclic polyisocyanates (eg, isophorone diisocyanate, cyclohexylmethane diisocyanate, etc.); aromatic diisocyanates (eg, , Tolylene diisocyanate, diphenylmethane diisocyanate, 1,5-naphthylene diisocyanate Diphenylene-4,4′-diisocyanate, 4,4′-diisocyanato-3,3′-dimethyldiphenyl, 3-methyldiphenylmethane-4,4′-diisocyanate, diphenyl ether-4,4′-diisocyanate); Aliphatic diisocyanates (eg, α, α, α ′, α′-tetramethylxylylene diisocyanate, etc.); isocyanurates (eg, tris-isocyanatoalkyl-isocyanurate, triisocyanatocycloalkyl-isocyanurate, etc.); These phenol derivatives; those blocked with oxime, caprolactam and the like can be mentioned. These may be used individually by 1 type and may use 2 or more types together.

  When the polyisocyanate and the hydroxyl group-containing polyester are reacted, a solvent can be used as necessary. There is no restriction | limiting in particular as said usable solvent, According to the objective, it can select suitably, For example, aromatic solvents (for example, toluene, xylene, etc.); Ketones (for example, acetone, methyl ethyl ketone, methyl isobutyl ketone) Etc.); esters (for example, ethyl acetate and the like); amides (for example, dimethylformamide, dimethylacetamide and the like); ethers (for example, tetrahydrofuran and the like) and the like which are inert to isocyanates. These may be used individually by 1 type and may use 2 or more types together.

  The mixing ratio of the polyisocyanate and the hydroxyl group-containing polyester is not particularly limited and may be appropriately selected depending on the intended purpose. However, the isocyanate group [NCO] of the polyisocyanate and the hydroxyl group of the polyester having the hydroxyl group [ The equivalent ratio [NCO] / [OH] to OH] is preferably 5/1 to 1/1, more preferably 4/1 to 1.2 / 1, and 2.5 / 1 to 1.5 / 1. Particularly preferred. When the equivalent ratio [NCO] / [OH] exceeds 5, the remaining polyisocyanate compound may adversely affect the chargeability of the toner.

-Active hydrogen group-containing compound-
The active hydrogen group-containing compound acts as an elongation agent, a crosslinking agent, or the like when the prepolymer undergoes an elongation reaction, a crosslinking reaction, or the like in an aqueous medium.
There is no restriction | limiting in particular as said active hydrogen group, According to the objective, it can select suitably, For example, a hydroxyl group (alcoholic hydroxyl group or phenolic hydroxyl group), an amino group, a carboxyl group, a mercapto group etc. are mentioned. These may be contained singly or in combination of two or more.

  The active hydrogen group-containing compound is not particularly limited as long as it has an active hydrogen group, and can be appropriately selected according to the purpose. Examples thereof include water, and the prepolymer contains an isocyanate group described later. In the case of a prepolymer, amines are preferable in terms of enabling high molecular weight.

The amines that are the active hydrogen group-containing compounds are not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include diamines, trivalent or higher polyamines, amino alcohols, amino mercaptans, amino acids, and the like. The thing etc. which blocked the amino group of amines are mentioned. Examples of the diamine include aromatic diamines (eg, phenylenediamine, diethyltoluenediamine, 4,4′diaminodiphenylmethane, etc.); alicyclic diamines (eg, 4,4′-diamino-3,3′dimethyldicyclohexylmethane). , Diamine cyclohexane, isophorone diamine, etc.); aliphatic diamines (eg, ethylene diamine, tetramethylene diamine, hexamethylene diamine, etc.) and the like. Examples of the trivalent or higher polyamine include diethylenetriamine and triethylenetetramine. Examples of the amino alcohol include ethanolamine and hydroxyethylaniline. Examples of the amino mercaptan include aminoethyl mercaptan and aminopropyl mercaptan. Examples of the amino acid __ include aminopropionic acid and aminocaproic acid. Examples of the blocked amino group of these amines include, for example, any of these amines (diamine, trivalent or higher polyamine, amino alcohol, amino mercaptan, amino acid, etc.) and ketones (for example, acetone, Methyl ethyl ketone, methyl isobutyl ketone and the like) and ketimine compounds, oxazolyson compounds and the like. These may be used individually by 1 type and may use 2 or more types together.
Among these, the amines are particularly preferably diamine and a mixture of a diamine and a small amount of a trivalent or higher polyamine.

A modified polyester resin is obtained by subjecting the active hydrogen group-containing compound and the prepolymer to an elongation or crosslinking reaction in an aqueous medium.
The elongation or cross-linking reaction may be stopped by a reaction terminator (for example, monoamine such as diethylamine, dibutylamine, butylamine, laurylamine, or the like blocked with a monoamine such as a ketimine compound).

In the synthesis of the modified polyester resin, the mixing ratio of the isocyanate group-containing prepolymer that is the prepolymer and the amines that are the active hydrogen group-containing compound is not particularly limited and is appropriately selected according to the purpose. As an equivalent ratio ([NCO] / [NHx]) of the isocyanate group [NCO] of the isocyanate group-containing prepolymer and the amino group [NHx] of the amines, it is 1/2 to 2/1. Is preferable, 1 / 1.5-1.5 / 1 is more preferable, and 1 / 1.2-1.2 / 1 is particularly preferable.
The content of the modified polyester resin in the toner is preferably 0.1% by mass to 50% by mass.

<< Crystalline resin >>
By containing the crystalline resin, the toner of the present invention can improve the low-temperature fixability and further improve the paper fastness.
The crystalline resin has a property that its crystal structure collapses in the vicinity of the melting point and the viscosity rapidly decreases. For this reason, good low-temperature fixability can be imparted while maintaining high heat-resistant storage stability. In addition, when the heat is exhausted from the paper, the elasticity is quickly recovered, so that the paper fastness can be improved.
As the crystalline resin, a crystalline polyester resin is preferable from the viewpoint of improving low-temperature fixability and further improving paper-fixing resistance.

About crystallinity, molecular structure, etc. of the crystalline polyester resin, NMR measurement, differential scanning calorimeter (DSC) measurement, X-ray diffraction measurement, GC / MS measurement, LC / MS measurement, infrared absorption (IR) spectrum measurement, Etc. can be confirmed. For example, in the infrared absorption (IR) spectrum, it is preferable to have absorption based on δch (out-of-plane variable angular vibration) of olefin in the range of 965 ± 10 cm ⁻¹ and 990 ± 10 cm ^−1. What is shown can be evaluated as crystalline.
The crystalline polyester resin can be synthesized, for example, by subjecting an alcohol component and an acid component to a polycondensation reaction.
There is no restriction | limiting in particular as said alcohol component, According to the objective, it can select suitably, For example, a diol compound etc. are mentioned suitably.

  As said diol compound, C2-C8 is preferable, for example, and 2-6 are more preferable, for example, 1, 4- butanediol, ethylene glycol, 1, 2- propylene glycol, 1, 3- propylene glycol, 1 , 6-hexanediol, neopentyl glycol, 1,4-butenediol, 1,5-pentanediol, or derivatives thereof. These can be used individually by 1 type and can use 2 or more types together. Among these, 1,4-butanediol and 1,6-hexanediol are particularly preferable.

As content of the said diol compound, 80 mol% or more is preferable in the said alcohol component, and 85 mol%-100 mol% are more preferable.
If the content of the diol compound in the alcohol component is less than 80 mol%, the production efficiency may deteriorate.

  There is no restriction | limiting in particular as said acid component, According to the objective, it can select suitably, For example, the carboxylic acid which has a carbon double bond, a dicarboxylic acid compound, a polyvalent carboxylic acid compound etc. are mentioned. Among these. Dicarboxylic acid compounds are preferred.

  As the dicarboxylic acid compound, for example, those having 2 to 8 carbon atoms are preferable, and those having 2 to 6 carbon atoms are more preferable. For example, oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid , Succinic acid, adipic acid, anhydrides of these acids, or alkyl esters having 1 to 3 carbon atoms thereof. These may be used individually by 1 type and may use 2 or more types together. Among these, fumaric acid is particularly preferable.

As the usage-amount of the said dicarboxylic acid compound, 80 mol% or more is preferable in the said acid component, and 85 mol%-100 mol% are more preferable. If the content of the dicarboxylic acid compound in the acid component is less than 80 mol%, the production efficiency may deteriorate.
Examples of the polyvalent carboxylic acid compound include trimellitic acid, pyromellitic acid, or acid anhydrides thereof, or alkyl esters having 1 to 3 carbon atoms of these acids.

  There is no restriction | limiting in particular as said polycondensation reaction, According to the objective, it can select suitably, For example, it reacts at 120 degreeC-230 degreeC using an esterification catalyst, a polymerization inhibitor, etc. in inert gas atmosphere. This can be done.

  When the polycondensation reaction is performed, a divalent monomer is reacted for the purpose of adding all monomers at once or reducing low molecular weight components for the purpose of improving the strength of the resulting crystalline polyester resin. After that, a trivalent or higher monomer can be added and reacted. Further, for the purpose of promoting the reaction, the reaction system can be decompressed in the latter half of the polycondensation reaction. For the purpose of controlling crystallinity and softening point in the crystalline polyester resin, a trihydric or higher polyhydric alcohol such as glycerin is added as the alcohol component during the polycondensation reaction, and trimellitic anhydride is used as the acid component. A non-linear polyester may be obtained by adding a trivalent or higher polyvalent carboxylic acid.

  The molecular weight distribution of the crystalline polyester resin is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably sharp, and the lower the molecular weight, the better the low-temperature fixability. In a molecular weight distribution chart in which the horizontal axis represents log (M) and the vertical axis represents mass%, the peak position is 3.5 to 4 according to gel permeation chromatograph (GPC) of soluble components of orthodichlorobenzene. 0.0 and the half width of the peak is preferably 1.5 or less.

There is no restriction | limiting in particular as a weight average molecular weight (Mw) of the said crystalline polyester resin, Although it can select suitably according to the objective, Since it will become difficult to maintain sharp melt property, when molecular weight is large, 1 1,000 to 30,000 are preferable, and 1,200 to 20,000 are more preferable.
There is no restriction | limiting in particular as a number average molecular weight (Mn) of the said crystalline polyester resin, Although it can select suitably according to the objective, 500-6,000 are preferable and 700-5,500 are more preferable.

The molecular weight distribution (Mw / Mn) represented by the ratio of the weight average molecular weight (Mw) and the number average molecular weight (Mn) is not particularly limited and can be appropriately selected according to the purpose. 2-8 are preferable.
When the molecular weight distribution (Mw / Mn) is less than 2, production may be difficult and costly. When it exceeds 8, the sharp melt property may be deteriorated.

The melting point of the crystalline polyester resin is preferably 60 ° C to 130 ° C. When the melting point is less than 60 ° C., the viscoelasticity of the toner decreases at a low temperature, which may deteriorate the heat-resistant storage stability. When the melting point exceeds 130 ° C., the effect of reducing the viscoelasticity is insufficient. In some cases, the low-temperature fixability may be insufficient.
The melting point of the crystalline polyester resin can be measured by, for example, a DSC curve obtained by differential scanning calorimetry (DSC).

There is no restriction | limiting in particular as an acid value of the said crystalline polyester resin, According to the objective, it can select suitably, For example, 5 mgKOH / g or more is preferable and 10 mgKOH / g or more is more preferable. On the other hand, from the viewpoint of improving the hot offset property, the acid value is preferably 45 mgKOH / g or less.
If the acid value is less than 5 mgKOH / g, the affinity between the recording medium (paper) and the binder resin and the desired low-temperature fixability may not be achieved.
The acid value of the crystalline polyester resin can be measured by, for example, dissolving and titrating in 1,1,1,3,3,3-hexafluoro-2-propanol.

There is no restriction | limiting in particular as a hydroxyl value of the said crystalline polyester resin, According to the objective, it can select suitably, For example, 0 mgKOH / g-50 mgKOH / g are preferable, and 5 mgKOH / g-50 mgKOH / g are more preferable.
If the hydroxyl value exceeds 50 mgKOH / g, low temperature fixability may be achieved and good charging characteristics may not be achieved.
The hydroxyl value of the crystalline polyester resin can be measured, for example, by dissolving and titrating in 1,1,1,3,3,3-hexafluoro-2-propanol.
The content of the crystalline polyester resin as the crystalline resin is preferably 0.1 to 50 parts by mass with respect to 100 parts by mass of the unmodified polyester resin as the amorphous resin.

<Colorant>
There is no restriction | limiting in particular as said coloring agent, According to the objective, it can select suitably, For example, carbon black, nigrosine dye, iron black, naphthol yellow S, Hansa yellow (10G, 5G, G), cadmium yellow, yellow Iron oxide, ocher, yellow lead, titanium yellow, polyazo yellow, oil yellow, Hansa yellow (GR, A, RN, R), pigment yellow L, benzidine yellow (G, GR), permanent yellow (NCG), Vulcan fast Yellow (5G, R), Tartrazine Lake, Quinoline Yellow Lake, Anthrazan Yellow BGL, Isoindolinone Yellow, Bengala, Red Dan, Lead Zhu, Cadmium Red, Cadmium Mercury Red, Antimon Zhu, Permanent Red 4R, Para Red, Phi Sared, parac Luort Nitroaniline Red, Resol Fast Scarlet G, Brilliant Fast Scarlet, Brilliant Carnmin BS, Permanent Red (F2R, F4R, FRL, FRLL, F4RH), Fast Scarlet VD, Belkan Fast Rubin B, Brilliant Scarlet G, Resol Rubin GX, Permanent Red F5R, Brilliant Carmine 6B, Pigment Scarlet 3B, Bordeaux 5B, Tolujing Maroon, Permanent Bordeaux F2K, Helio Bordeaux BL, Bordeaux 10B, Bon Maroon Light, Bon Maroon Medium, Eosin Lake, Rhodamine Lake B, Rhodamine Lake Y, Alizarin Lake, thioindigo red B, thioindigo maroon, oil red, quinacridone red, pi Zoron Red, Polyazo Red, Chrome Vermillion, Benzidine Orange, Perinone Orange, Oil Orange, Cobalt Blue, Cerulean Blue, Alkaline Blue Lake, Peacock Blue Lake, Victoria Blue Lake, Metal Free Phthalocyanine Blue, Phthalocyanine Blue, Fast Sky Blue, Indance Ren Blue (RS, BC), Indigo, Ultramarine Blue, Bitumen, Anthraquinone Blue, Fast Violet B, Methyl Violet Lake, Cobalt Purple, Manganese Purple, Dioxane Violet, Anthraquinone Violet, Chrome Green, Zinc Green, Chrome Oxide, Pyridian, Emerald Green , Pigment Green B, Naphthol Green B, Green Gold, Acid Green Lake, Malachite Gree Rake, phthalocyanine green, anthraquinone green, titanium oxide, zinc white, litbon and the like.

  There is no restriction | limiting in particular as content of the said coloring agent, Although it can select suitably according to the objective, 1 mass%-15 mass% are preferable with respect to the said toner, and 3 mass%-10 mass% are preferable. More preferred. When the content is less than 1% by mass, coloring power may be insufficient, and when the content exceeds 15% by mass, toner fixing may be inhibited.

  The colorant can also be used as a master batch combined with a resin. As the resin to be kneaded with the production of the master batch or the master batch, in addition to the above-mentioned modified or unmodified polyester resin, styrene such as polystyrene, poly p-chlorostyrene, polyvinyltoluene, or a substituted polymer thereof; styrene-p -Chlorostyrene copolymer, styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene- Butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-α-chloromethacrylic acid Methyl copolymer, styrene-acrylic Ronitrile copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer, styrene-maleic acid copolymer, styrene-maleic acid ester Styrene copolymers such as copolymers; polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, epoxy resin, epoxy polyol resin, polyurethane, polyamide, polyvinyl butyral, polyacrylic acid Examples thereof include resins, rosins, modified rosins, terpene resins, aliphatic or alicyclic hydrocarbon resins, aromatic petroleum resins, chlorinated paraffins, and paraffin waxes. These may be used individually by 1 type and may use 2 or more types together.

  The masterbatch can be obtained by mixing a masterbatch resin and a colorant under high shear force and kneading to obtain a masterbatch. In this case, an organic solvent can be used in order to enhance the interaction between the colorant and the resin. In addition, a so-called flushing method, which is a wet method of colorant, is a method of mixing and kneading an aqueous paste containing water of a colorant together with a resin and an organic solvent, transferring the colorant to the resin side, and removing moisture and organic solvent components. Since the cake can be used as it is, it does not need to be dried and is preferably used. For mixing and kneading, a high shear dispersion device such as a three-roll mill is preferably used.

<Other ingredients>
There is no restriction | limiting in particular as said other component, According to the objective, it can select suitably, For example, a mold release agent, a charge control agent, resin fine particles, a magnetic material etc. are mentioned.

-Release agent-
There is no restriction | limiting in particular as said mold release agent, According to the objective, it can select suitably.
Examples of the waxes and waxes include plant waxes such as carnauba wax, cotton wax, wood wax and rice wax; animal waxes such as beeswax and lanolin; mineral waxes such as ozokerite and cercin; paraffin and micro wax And natural waxes such as petroleum waxes such as crystallin and petrolatum. In addition to these natural waxes, synthetic hydrocarbon waxes such as Fischer-Tropsch wax, polyethylene wax, and polypropylene; synthetic waxes such as esters, ketones, and ethers;

  Furthermore, fatty acid amide compounds such as 12-hydroxystearic acid amide, stearic acid amide, phthalic anhydride imide, chlorinated hydrocarbon; low molecular weight crystalline polymer resin, poly-n-stearyl methacrylate, poly-n -Polyacrylate homopolymer or copolymer such as lauryl methacrylate (eg, n-stearyl acrylate-ethyl methacrylate copolymer); crystalline polymer having a long alkyl group in the side chain, etc. Good.

As said mold release agent, these may be used individually by 1 type and may use 2 or more types together. Among these, as the release agent of the present invention, hydrocarbon waxes such as paraffin, polyethylene, and polypropylene are preferable. Since the hydrocarbon wax has low compatibility with the fixing auxiliary component of the present invention and can act independently without impairing the functions of each other, sufficient low-temperature fixability can be obtained.
The content of the release agent in the toner is preferably 1% by mass to 40% by mass, and more preferably 5% by mass to 35% by mass.

-Charge control agent-
The charge control agent is not particularly limited and may be appropriately selected from known ones according to the purpose. Examples thereof include nigrosine dyes, triphenylmethane dyes, chromium-containing metal complex dyes, and molybdate chelate pigments. , Rhodamine dyes, alkoxy amines, quaternary ammonium salts (including fluorine-modified quaternary ammonium salts), alkylamides, phosphorus alone or compounds thereof, tungsten alone or compounds thereof, fluorine activators, salicylic acid metal salts And metal salts of salicylic acid derivatives. These may be used individually by 1 type and may use 2 or more types together.

  Commercially available products may be used as the charge control agent. Examples of the commercially available products include bontron 03 of a nigrosine dye, bontron P-51 of a quaternary ammonium salt, and bontron S-34 of a metal-containing azo dye. , E-82 of oxynaphthoic acid metal complex, E-84 of salicylic acid metal complex, E-89 of phenol condensate (both manufactured by Orient Chemical Co., Ltd.); TP of quaternary ammonium salt molybdenum complex -302, TP-415 (both manufactured by Hodogaya Chemical Co., Ltd.); quaternary ammonium salt copy charge PSY VP2038, triphenylmethane derivative copy blue PR, quaternary ammonium salt copy charge NEG VP2036, Copy charge NX VP434 (both manufactured by Hoechst); LRA-901, boron complex LR-147 (manufactured by Nippon Carlit Co., Ltd.); copper phthalocyanine, perylene, quinacridone, azo pigments, other polymer compounds having functional groups such as sulfonic acid groups, carboxyl groups, quaternary ammonium salts, etc. Can be mentioned.

The content of the charge control agent in the toner varies depending on the type of the binder resin, the presence / absence of an additive, a dispersion method, and the like, and cannot be generally specified. 0.1 mass part-10 mass parts are preferable, and 0.2 mass part-5 mass parts are more preferable. When the content is less than 0.1 parts by mass, the charge controllability may not be obtained. When the content exceeds 10 parts by mass, the chargeability of the toner becomes too large and the effect of the main charge control agent is reduced. As a result, the electrostatic attractive force with the developing roller increases, which may lead to a decrease in developer fluidity and a decrease in image density.
The charge control agent can be dissolved and dispersed after being melt-kneaded with a masterbatch and resin, and of course, it may be added when directly dissolving and dispersing in an organic solvent, or it may be fixed on the toner surface after preparation of toner particles. Also good.

-Resin fine particles-
The resin fine particles are not particularly limited and can be appropriately selected depending on the purpose. For example, vinyl resin, polyurethane resin, epoxy resin, polyester resin, polyamide resin, polyimide resin, silicon resin, phenol resin, Examples include melamine resin, urea resin, aniline resin, ionomer resin, and polycarbonate resin. Among these, a vinyl resin, a polyurethane resin, an epoxy resin, a polyester resin, and a combination thereof are preferable, and a vinyl resin is more preferable because an aqueous dispersion of fine spherical resin particles is easily obtained.

  Examples of the vinyl resin include polymers obtained by homopolymerization or copolymerization of vinyl monomers, such as styrene- (meth) acrylic acid ester resins, styrene-butadiene copolymers, and (meth) acrylic acid-acrylic acid ester polymers. Styrene-acrylonitrile copolymer, styrene-maleic anhydride copolymer, styrene- (meth) acrylic acid copolymer, and the like. Among these, a styrene-butyl methacrylate copolymer is preferable.

Moreover, as the resin fine particles, a copolymer comprising a monomer having at least two unsaturated groups can be used.
The monomer having at least two unsaturated groups is not particularly limited and may be appropriately selected depending on the intended purpose. For example, a sodium salt of ethylene oxide methacrylate adduct sulfate (“Eleminol RS-30”). ", Sanyo Chemical Industries, Ltd.), divinylbenzene, 1,6-hexanediol acrylate and the like.

The resin fine particles preferably have a glass transition temperature (Tg) of 50 ° C to 70 ° C. When the glass transition temperature (Tg) is less than 50 ° C., the heat-resistant storage stability of the toner is deteriorated, and blocking may occur during storage and in the developing means. The resin fine particles may hinder the adhesion to the fixing paper, and the minimum fixing temperature may increase.
There is no restriction | limiting in particular as a weight average molecular weight of the said resin fine particle, Although it can select suitably according to the objective, 9,000-200,000 are preferable. When the weight average molecular weight is less than 9,000, the heat-resistant storage stability may be lowered, and when it exceeds 200,000, the low-temperature fixability may be lowered.
In the resin fine particles, the average particle size is preferably 5 nm to 200 nm, more preferably 20 nm to 150 nm.

  There is no restriction | limiting in particular as content of the said resin fine particle, Although it can select suitably according to the objective, 0.5 mass%-5.0 mass% are preferable. If the content is less than 0.5% by mass, it may be difficult to control the surface hardness and fixability of the toner. If the content exceeds 5.0% by mass, the resin fine particles may exude wax. May be offset and an offset may occur.

-Magnetic material-
There is no restriction | limiting in particular as said magnetic material, According to the objective, it can select suitably from well-known things, For example, iron powder, a magnetite, a ferrite etc. are mentioned. Among these, white is preferable in terms of color tone.

<Toner production method>
The method for producing the toner used in the present invention is not particularly limited, and can be appropriately selected from conventionally known toner production methods according to the purpose. And other steps as necessary.

<< Toner Base Particle Preparation Process >>
The toner base preparation step is a step of preparing toner base particles containing at least a binder resin and a colorant, and examples thereof include a kneading pulverization method, a polymerization method, a dissolution suspension method, and a spray granulation method. . Among these, a polymerization method such as dissolution suspension is particularly preferable from the viewpoint of easy particle size and shape control.

-Kneading and grinding method-
The kneading and pulverizing method is, for example, a method of producing base particles of the toner by melt-kneading a toner material containing at least a binder resin and a colorant, pulverizing and classifying the obtained kneaded material. is there. In the melt kneading, the toner materials are mixed, and the mixture is charged into a melt kneader and melt kneaded. As the melt kneader, for example, a uniaxial or biaxial continuous kneader or a batch kneader using a roll mill can be used. For example, a KTK type twin screw extruder manufactured by Kobe Steel, a TEM type extruder manufactured by Toshiba Machine Co., Ltd., a twin screw extruder manufactured by Casey Kay Co., Ltd., a PCM type twin screw extruder manufactured by Ikegai Co., Ltd. Used. This melt-kneading is preferably performed under appropriate conditions so as not to cause the molecular chains of the binder resin to be broken. Specifically, the melt-kneading temperature is determined with reference to the softening point of the binder resin. If the temperature is higher than the softening point, cutting is severe, and if the temperature is too low, dispersion may not proceed.

In the pulverization, the kneaded product obtained by the kneading is pulverized. In this pulverization, it is preferable that the kneaded material is first coarsely pulverized and then finely pulverized. At this time, a method of pulverizing by colliding with a collision plate in a jet stream, pulverizing particles by colliding with each other in a jet stream, or pulverizing with a narrow gap between a mechanically rotating rotor and a stator is preferably used.
In the classification, the pulverized product obtained by the pulverization is classified and adjusted to particles having a predetermined particle diameter. The classification can be performed, for example, by removing the fine particle portion with a cyclone, a decanter, a centrifuge, or the like. After the pulverization and classification are completed, the pulverized product is classified in an air stream by a centrifugal force or the like to produce toner base particles having a predetermined particle size.

-Polymerization method-
Examples of the method for producing a toner by the polymerization method include, for example, an active hydrogen group-containing compound in an organic solvent, and a binder resin precursor, a binder resin, and a colorant having a site capable of reacting with the active hydrogen group-containing compound. And a dispersion or dispersion obtained by dissolving or dispersing the release agent in an aqueous medium to obtain an emulsion dispersion, and the binder resin precursor and the active hydrogen group are obtained in the obtained emulsion dispersion. It is characterized by reacting with the contained compound and removing the organic solvent. Specifically, it includes an oil phase preparation step, an aqueous phase preparation step, a toner dispersion preparation step, and a solvent removal step. The process is comprised.

-Oil phase preparation process-
As the oil phase preparation step, an active hydrogen group-containing compound and a binder resin precursor having a site capable of reacting with the active hydrogen group-containing compound, a binder resin, a colorant, and a release agent in an organic solvent If it is the process of preparing the melt | dissolution thru | or dispersion liquid which melt | dissolved thru | or disperse | distributed, there will be no restriction | limiting in particular, According to the objective, it can select suitably.
Examples of the method for preparing the oil phase include, for example, an active hydrogen group-containing compound and a binder resin precursor having a site capable of reacting with the active hydrogen group-containing compound in the organic solvent while stirring the organic solvent. Examples include a method of gradually adding a body, a binder resin, a colorant, a release agent, and, if necessary, the charge control agent, and dissolving or dispersing.

When using a pigment as the colorant, or when adding an organic solvent that is difficult to dissolve in an organic solvent such as the charge control agent, the particles are made smaller prior to addition to the organic solvent. It is preferable.
Making the colorant into a masterbatch is one suitable means, and the same method can be applied to the ester wax and the charge control agent.
As another method, it is also possible to add a dispersion aid as necessary in the organic solvent and disperse the colorant, the release agent, the charge control agent, etc. in a wet manner to obtain a wet master. is there.

  Further, as another method, if a material that melts below the boiling point of the organic solvent is dispersed, a dispersion aid is added in the organic solvent as necessary, and the mixture is heated while stirring with the dispersoid. It is possible to perform a method in which, after once dissolved, crystallization is performed by cooling while applying stirring or shearing to produce fine crystals of dispersoids.

  The active hydrogen group-containing compound and the site capable of reacting with the active hydrogen group-containing compound in the organic solvent with the colorant, the release agent, and if necessary, the charge control agent dispersed by the above method. Dispersion may be performed after dissolving or dispersing together with the binder resin precursor having a binder and the binder resin. There is no restriction | limiting in particular in the case of the said dispersion | distribution, Dispersing machines, such as a well-known bead mill and a disk mill, can be used.

  Also, a binder resin precursor having a functional group capable of reacting with the active hydrogen group-containing compound in the oil phase for the purpose of increasing the mechanical strength of the obtained toner or preventing high temperature offset during fixing. The toner is preferably produced in a state in which the oil phase is dissolved, that is, the oil phase contains the active hydrogen group-containing compound and the binder resin precursor.

  There is no restriction | limiting in particular as an organic solvent used in the said oil phase preparation process, Although it can select suitably according to the objective, The point which a subsequent organic solvent removal becomes easy that a boiling point is less than 100 degreeC. To preferred. Examples of the organic solvent include toluene, xylene, benzene, carbon tetrachloride, methylene chloride, 1,2-dichloroethane, 1,1,2-trichloroethane, trichloroethylene, chloroform, monochlorobenzene, dichloroethylidene, methyl acetate, and ethyl acetate. , Methyl ethyl ketone, methyl isobutyl ketone and the like. These may be used individually by 1 type and may use 2 or more types together.

  When the binder resin to be dissolved or dispersed in the organic solvent is a resin having a polyester skeleton, for example, an ester solvent such as methyl acetate, ethyl acetate or butyl acetate, or a ketone solvent such as methyl ethyl ketone or methyl isobutyl ketone is used. Is preferable from the viewpoint of excellent solubility. Of these, methyl acetate, ethyl acetate, and methyl ethyl ketone, which have high solvent removability, are particularly preferable.

--Aqueous phase preparation process--
The aqueous phase preparation step is not particularly limited as long as it is a step of preparing an aqueous phase, and can be appropriately selected according to the purpose.
There is no restriction | limiting in particular as an aqueous medium used in the said aqueous phase preparation process, According to the objective, it can select suitably, For example, water is mentioned. The aqueous medium may be water alone or an organic solvent miscible with water. Examples of the organic solvent miscible with water include alcohols (eg, methanol, isopropanol, ethylene glycol), dimethylformamide, tetrahydrofuran, cellosolves (eg, methyl cellosolve), and lower ketones (eg, acetone, methyl ethyl ketone). Etc.).
The aqueous medium preferably further contains a surfactant.

  The surfactant is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include anionic surfactants such as alkylbenzene sulfonates, α-olefin sulfonates, phosphate esters, and disulfonates. Agent: alkylamine salt, amino alcohol fatty acid derivative, polyamine fatty acid derivative, amine salt type such as imidazoline, alkyltrimethylammonium salt, dialkyldimethylammonium salt, alkyldimethylbenzylammonium salt, pyridinium salt, alkylisoquinolinium salt, chloride Cationic surfactants such as quaternary ammonium salt types such as benzethonium; Nonionic surfactants such as fatty acid amide derivatives and polyhydric alcohol derivatives; alanine, dodecyldi (aminoethyl) glycine, di (octylaminoethyl) glycine, N -A Kill -N, such amphoteric surface active agents such as tine base N- dimethyl ammonium. Among these, in order to efficiently disperse oil droplets containing a solvent, a disulfonate having a high HLB is preferable.

  There is no restriction | limiting in particular as content of surfactant contained in the said aqueous medium, Although it can select suitably according to the objective, The density | concentration in the said aqueous medium is 3 mass%-10 mass%. Preferably, 4 mass%-9 mass% are more preferable, and 5 mass%-8 mass% are especially preferable. When the concentration is less than 3% by mass, the oil droplets cannot be stably dispersed and the oil droplets may become coarse. When the concentration exceeds 10% by mass, the oil droplets become too small. In addition, a reverse micelle structure may be formed, and the dispersion stability may be reduced, resulting in coarse oil droplets.

--Toner dispersion preparation process--
The toner dispersion preparation step is not particularly limited as long as it is a step of preparing an emulsified dispersion (toner dispersion) by dispersing the oil phase in the aqueous phase, and is appropriately selected according to the purpose. Can do.
The dispersion method is not particularly limited and may be appropriately selected depending on the intended purpose. For example, using a known facility such as a low-speed shear method, a high-speed shear method, a friction method, a high-pressure jet method, or an ultrasonic wave. A method of dispersing is mentioned. In order to make the particle size of the toner base particles 2 μm to 20 μm, dispersion using a high-speed shearing disperser is preferable.

  When a high-speed shearing disperser is used, the rotational speed is not particularly limited and can be appropriately selected according to the purpose, but is preferably 1,000 rpm to 30,000 rpm, and is preferably 5,000 rpm to 20,000 rpm. More preferred. There is no restriction | limiting in particular as dispersion time, According to the objective, it can select suitably, However, In the case of a batch system, 0.1 minute-5 minutes are preferable. When the dispersion time exceeds 5 minutes, particles having an undesirably small diameter may remain, or the dispersion may be in an overdispersed state, resulting in unstable system and generation of aggregates and coarse particles. .

  There is no restriction | limiting in particular as temperature at the time of dispersion | distribution, Although it can select suitably according to the objective, 0 to 40 degreeC is preferable and 10 to 30 degreeC is more preferable. When the temperature at the time of dispersion is less than 0 ° C., the viscosity of the dispersion increases, and shear energy necessary for dispersion increases, so that the production efficiency may decrease. When the temperature at the time of dispersion exceeds 40 ° C., molecular motion becomes active, so that dispersion stability is lowered, and aggregates and coarse particles may be easily generated.

There is no restriction | limiting in particular as content of the organic solvent contained in the said toner dispersion liquid, Although it can select suitably according to the objective, 10 mass%-70 mass% are preferable, and 25 mass%-60 mass% are preferable. Is more preferable, and 40% by mass to 55% by mass is particularly preferable.
Note that the content of the organic solvent contained in the toner dispersion is determined based on solid content (the binder resin, the colorant, the release agent, and, if necessary, the charge control agent in the state of the toner dispersion. Etc.).

-Solvent removal step-
The solvent removal step is not particularly limited as long as it is a step for removing the solvent contained in the toner dispersion, and can be appropriately selected according to the purpose. However, the organic solvent contained in the toner dispersion is completely removed. The step of removing is preferable, for example, a method in which the temperature of the toner dispersion is gradually raised while stirring to completely evaporate and remove the organic solvent in the droplets, and the toner dispersion is sprayed into a dry atmosphere while stirring. And a method of completely removing the organic solvent in the droplets and a method of evaporating and removing the organic solvent by reducing the pressure of the toner dispersion while stirring. The latter two means can be used in combination with the first means.

The drying atmosphere in which the toner dispersion is sprayed is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include a gas obtained by heating air, nitrogen, carbon dioxide gas, combustion gas, and the like.
There is no restriction | limiting in particular as temperature of the said dry atmosphere, Although it can select suitably according to the objective, Temperature more than the boiling point of the highest boiling point solvent is preferable.
The spraying is performed using, for example, a spray dryer, a belt dryer, a rotary kiln, or the like. When these are used, the target quality can be sufficiently obtained in a short time.

-Other processes-
There is no restriction | limiting in particular as said other process, According to the objective, it can select suitably, For example, a maturing process, a washing | cleaning process, a drying process, etc. are mentioned.

--- Aging process ---
When the oil phase contains a polyester resin (prepolymer) having a functional group capable of reacting with the active hydrogen group of the active hydrogen group-containing compound, an aging step is performed to advance the prepolymer elongation and crosslinking reaction. Preferably it is done.
The aging step is preferably performed after the solvent removal step and before the washing step.
There is no restriction | limiting in particular as an aging time in the said aging process, Although it can select suitably according to the objective, 10 minutes-40 hours are preferable, and 2 hours-24 hours are more preferable. There is no restriction | limiting in particular as reaction temperature in the said ripening process, Although it can select suitably according to the objective, 0 to 65 degreeC is preferable and 35 to 50 degreeC is more preferable.

--- Cleaning process ---
The washing step is not particularly limited as long as it is a step for washing the toner (toner base particles) contained in the toner dispersion following the solvent removal step or the aging step. It can be appropriately selected depending on the situation.
Since the toner dispersion liquid contains secondary materials such as a dispersant such as a surfactant in addition to the toner base particles, cleaning is performed to extract only the toner base particles from the toner dispersion liquid.
The cleaning method for the toner base particles is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include a centrifugal separation method, a vacuum filtration method, and a filter press method. Either method can provide a cake of toner base particles. However, if the cake cannot be sufficiently washed by a single operation, the obtained cake is dispersed again in an aqueous medium to form a slurry, and the toner is prepared by any of the methods described above. The step of taking out the base particles may be repeated, and if cleaning is performed by a vacuum filtration method or a filter press method, an aqueous medium is passed through the cake to wash away the secondary material that the toner base particles have embraced. Also good. As the aqueous medium used for the washing, water or a mixed solvent obtained by mixing water and alcohol such as methanol or ethanol is used. However, in view of cost and environmental load due to wastewater treatment, it is preferable to use water.

--- Drying process ---
The drying step is not particularly limited as long as it is a step of drying the toner base particles after the washing step, and can be appropriately selected according to the purpose.
Since the toner base particles cleaned by the cleaning step contain a large amount of water, only toner base particles can be obtained by drying and removing the water from the particles.
The method for removing moisture from the toner base particles is not particularly limited and may be appropriately selected depending on the intended purpose. For example, spray dryer, vacuum freeze dryer, vacuum dryer, stationary shelf dryer, transfer Examples include a method using a dryer such as a type shelf dryer, a fluidized tank dryer, a rotary dryer, and a stirring dryer.
It is preferable to remove the water until the water content of the toner base particles is less than 1% by mass. In addition, if the toner base particles after moisture removal are softly agglomerated and inconvenience occurs, use a device such as a jet mill, Henschel mixer, super mixer, coffee mill, auster blender, or food processor. Crushing may be performed to loosen the soft agglomeration.

<< External treatment process >>
The external addition treatment step is a step of externally adding an external additive containing the organic / inorganic fine particles or the like to the toner base particles.
The external addition method of the inorganic fine particles to the toner base particles is not particularly limited and may be appropriately selected depending on the purpose. Examples thereof include a method of external addition using a high-speed flow mixer or the like. It is necessary to adjust the process so that the liberation rate of the hydrophobic silica fine particles in the final toner falls within the numerical range defined in the present invention.
Therefore, if necessary, these additives may be pulverized separately or mixed in advance to remove coarse agglomerates and externally added to toner particles, toner base particles, various inorganic fine particles, Other materials may be added individually and mixed, or a method of mixing external additives by another means after mixing may be used.

  In the present invention, in order to adjust the liberation rate of the hydrophobic silica particles to the above numerical range, various conditions such as the rotational speed, time, temperature, etc. of the high-speed fluid mixer when externally adding inorganic fine particles to the toner base particles It is preferable to change the adhesion state of the external additive by changing.

The volume average particle diameter Dv of the toner of the present invention is preferably 3.0 μm to 7.0 μm, and more preferably 3.5 μm to 6.5 μm. The ratio of the volume average particle diameter to the number average particle diameter (Dv / Dn) is preferably 1.2 or less, more preferably 1.10 to 1.20. Moreover, it is preferable to contain 1% by number or more and 10% by number or less of a component having a particle size of 2 μm or less.
When the volume average particle size is 3.0 μm or more, the cleaning property of the toner remaining on the surface of the electrostatic latent image carrier is good. Will also be good.

Here, as a toner particle size distribution measuring device, for example, Coulter Multisizer III (manufactured by Coulter, Inc.) is used. The measurement method is described below.
First, 0.1 mL to 5 mL of a surfactant (preferably alkyl benzene sulfonate) is added as a dispersant to 100 mL to 150 mL of the electrolytic aqueous solution. Here, the electrolytic solution is prepared by preparing a 1% by mass NaCl aqueous solution using first grade sodium chloride, and for example, ISOTON-II (manufactured by Coulter) can be used. Here, 2 mg to 20 mg of a measurement sample is further added. The electrolytic solution in which the sample is suspended is subjected to a dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes, and the measurement device is used to measure the volume and number of toner particles or toner using a 100 μm aperture as the aperture. Volume distribution and number distribution are calculated. From the obtained distribution, the volume average particle diameter Dv and the number average particle diameter Dn of the toner can be obtained.

-Average circularity-
The average circularity of the toner is preferably 0.93 to 0.99, and more preferably 0.94 to 0.98. When the average circularity is 0.93 or more, the primary transfer from the electrostatic latent image bearing member to the transfer paper or the intermediate transfer member or the secondary transfer property from the intermediate transfer member to the transfer paper becomes good, and the 0.99 or less. Thus, the cleaning property of the toner remaining on the surface of the electrostatic latent image carrier is improved.
Here, the average circularity of the toner can be measured as follows.

Ultra fine powder toner is measured using a flow type particle image analyzer (“FPIA-2100”, manufactured by Sysmex Corporation), and analyzed using analysis software (FPIA-2100 Data Processing Program for FPIA version 00-10). It was. Specifically, 0.1% to 0.5 ml of 10% by weight surfactant (alkylbenzene sulfonate, Neogen SC-A, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) is added to a glass 100 mL beaker, and each toner 0 0.1 g to 0.5 g was added, and the mixture was stirred with a micropartel, and then 80 mL of ion-exchanged water was added.
The obtained dispersion was subjected to a dispersion treatment for 3 minutes with an ultrasonic disperser (manufactured by Honda Electronics Co., Ltd.). The shape and distribution of the toner were measured using the FPIA-2100 until the density of the dispersion was 5,000 / μL to 15,000 / μL.

  In this measurement method, it is important that the concentration of the dispersion is 5,000 / μL to 15,000 / μL from the viewpoint of measurement reproducibility of the average circularity. In order to obtain the dispersion concentration, it is necessary to change the conditions of the dispersion, that is, the amount of surfactant to be added and the amount of toner. The amount of the surfactant varies depending on the hydrophobicity of the toner as in the measurement of the toner particle diameter described above. If it is added in a large amount, noise due to bubbles is generated, and if it is too small, the toner cannot be sufficiently wetted. It will be enough. The amount of toner added is different from the particle size, and is small for small particles and large for large particles. When the toner particle size is 3 μm to 7 μm, the toner amount is 0.1 g. By adding ˜0.5 g, the dispersion concentration can be adjusted to 5,000 / μL to 15,000 / μL.

  The coloration of the toner of the present invention is not particularly limited and can be appropriately selected according to the purpose, and can be at least one selected from black toner, cyan toner, magenta toner and yellow toner. This toner can be obtained by appropriately selecting the type of the colorant.

<Developer>
The developer used in the present invention contains at least the toner of the present invention, and other components appropriately selected such as a carrier. The developer may be a one-component developer or a two-component developer. However, when it is used for a high-speed printer or the like corresponding to the recent improvement in information processing speed, the life is improved. In view of the above, the two-component developer is preferable.

  In the case of the one-component developer using the toner of the present invention, the toner particle diameter hardly fluctuates even if the toner is balanced, so that the toner filming on the developing roller and the toner layer are made thin. The toner is not fused to a member such as a blade, and good and stable developability and images can be obtained even when the developing means is used (stirred) for a long time. Further, in the case of the two-component developer using the toner of the present invention, even if the toner balance over a long period of time is performed, there is little fluctuation in the toner particle diameter in the developer, and even during long-term stirring in the developing means, Good and stable developability can be obtained.

There is no restriction | limiting in particular as said carrier, Although it can select suitably according to the objective, What has a core material and the resin layer which coat | covers this core material is preferable. There is no restriction | limiting in particular as a material of the said core material, It can select suitably from well-known things, For example, a manganese-strontium (Mn-Sr) type material of 50 emu / g-90 emu / g, manganese-magnesium ( Mn—Mg) -based materials and the like are preferable, and highly magnetized materials such as iron powder (100 emu / g or more) and magnetite (75 emu / g to 120 emu / g) are preferable in terms of securing image density. Further, a weakly magnetized material such as a copper-zinc (Cu—Zn) type (30 emu to 80 emu / g) is advantageous in that it can weaken the contact with the photoconductor in which the toner is in a spiked state and is advantageous in improving the image quality. Is preferred. These may be used alone or in combination of two or more.
The core material has a volume average particle size of preferably 10 μm to 150 μm, more preferably 20 μm to 80 μm.

  When the average particle diameter (volume average particle diameter (D50)) is less than 10 μm, in the distribution of carrier particles, the fine powder system increases, the magnetization per particle is lowered, and carrier scattering may occur. If the thickness exceeds 150 μm, the specific surface area may be reduced and toner scattering may occur. In the case of a full color with many solid portions, the reproduction of the solid portions may be particularly poor.

  The material of the resin layer is not particularly limited and can be appropriately selected from known resins according to the purpose. For example, amino resins, polyvinyl resins, polystyrene resins, halogenated olefin resins, Polyester resin, polycarbonate resin, polyethylene resin, polyvinyl fluoride resin, polyvinylidene fluoride resin, polytrifluoroethylene resin, polyhexafluoropropylene resin, copolymer of vinylidene fluoride and acrylic monomer, vinylidene fluoride And a copolymer of vinyl fluoride, a fluoroterpolymer such as a terpolymer of tetrafluoroethylene, vinylidene fluoride, and a non-fluorinated monomer, and a silicone resin. These may be used individually by 1 type and may use 2 or more types together.

  Examples of the amino resin include urea-formaldehyde resin, melamine resin, benzoguanamine resin, urea resin, polyamide resin, and epoxy resin. Examples of the polyvinyl resin include acrylic resin, polymethyl methacrylate resin, polyacrylonitrile resin, polyvinyl acetate resin, polyvinyl alcohol resin, and polyvinyl butyral resin. Examples of the polystyrene resin include polystyrene resin and styrene-acrylic copolymer resin. Examples of the halogenated olefin resin include polyvinyl chloride. Examples of the polyester resin include polyethylene terephthalate resin and polybutylene terephthalate resin.

The resin layer may contain conductive powder or the like as required. Examples of the conductive powder include metal powder, carbon black, titanium oxide, tin oxide, and zinc oxide. The average particle diameter of these conductive powders is preferably 1 μm or less. When the average particle diameter exceeds 1 μm, it may be difficult to control electric resistance.
For example, the resin layer is prepared by dissolving the silicone resin or the like in a solvent to prepare a coating solution, and then uniformly coating the coating solution on the surface of the core material by a known coating method, drying, and baking. It can be formed by doing. Examples of the coating method include a dipping method, a spray method, and a brush coating method.

There is no restriction | limiting in particular as said solvent, Although it can select suitably according to the objective, For example, toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, cersol butyl acetate, etc. are mentioned.
The baking is not particularly limited, and may be an external heating method or an internal heating method. For example, a stationary electric furnace, a fluid electric furnace, a rotary electric furnace, a burner furnace, etc. The method of using, the method of using a microwave, etc. are mentioned.

The amount of the resin layer in the carrier is preferably 0.01% by mass to 5.0% by mass. When the amount is less than 0.01% by mass, the uniform resin layer may not be formed on the surface of the core material. When the amount exceeds 5.0% by mass, the resin layer becomes thick. In some cases, granulation of carriers occurs, and uniform carrier particles may not be obtained.
When the developer is the two-component developer, the content of the carrier in the two-component developer is not particularly limited and may be appropriately selected depending on the intended purpose. 98 mass% is preferable and 93 mass%-97 mass% are more preferable.

<Developing means>
The developing means used in the present invention includes a developer container for storing toner as a developer and a developing roller for supplying the developer to the electrostatic latent image carrier.
The developer container contains the toner of the present invention, but the container is not particularly limited and may be appropriately selected. Examples thereof include a container having a container body and a cap. Further, the size, shape, structure, material and the like of the container body are not particularly limited and can be appropriately selected according to the purpose. However, the shape is preferably cylindrical or the like, A spiral unevenness is formed on the surface, and by rotating it, the developer as the contents can be transferred to the discharge port side, and a part or all of the spiral unevenness has a bellows function. Particularly preferred. The material is not particularly limited and may be appropriately selected according to the purpose. However, it is preferable that the material has good dimensional accuracy. For example, polyester resin, polyethylene resin, polypropylene resin, polystyrene resin, polyvinyl chloride Examples thereof include resins, polyacrylic acid, polycarbonate resins, ABS resins, and polyacetal resins.

In the present invention, when the linear velocity of the developing roller in the developing means of the image forming apparatus is A [mm / sec] and the developer capacity in the unit is B [g], A and B are expressed by the following relational expression. Satisfy (1).
2.2 ≦ A / B ≦ 2.6 (1)
The developer capacity in the present invention is the amount of developer contained in a developer container necessary for the image forming apparatus to provide a high-quality image without an image error, and this is a fluctuating value. . In general, in order to provide an image stably, the developer capacity takes a substantially constant value, so that “A / B” is an inherent value depending on the image forming apparatus, but the developer capacity varies greatly. However, even if the operation is performed, if it falls within the range of 2.2 ≦ A / B ≦ 2.6 during the normal operation, the stress on the developer is greatly applied, so that this patent is included. It will be.
In the case of operation with a developer capacity of 95 g or less, the developer is too small for screw stirring in a high-speed machine and does not mix properly, and the operation with the developer capacity of 125 g or more is installed in a general small machine. Too much developer container.
For this reason, the developer capacity (B) is preferably in the range of 95 ≦ B ≦ 125.
When the developer capacity is 95 g or less, the amount of developer is small and it is difficult to uniformly stir with a high speed machine, and when it is 125 g or more, it is difficult to mount on a small machine.

FIG. 8 shows a configuration diagram of a process cartridge incorporating the developing means.
In the process cartridge shown in FIG. 8, a developing roller (hereinafter also referred to as “developing sleeve” or “conductive sleeve”) 805 is provided in the developing means 803.
The developing roller linear speed A [mm / sec] is preferably in the range of 210 ≦ (A) ≦ 320.
If A is 210 mm / sec or less, the small-sized machine cannot supply the toner used for development in time, and if it is 320 mm / sec or more, toner scraping occurs due to the rotation of the stirring screw for the developer, causing an image error. . Further, from the above viewpoint, the developing roller is also required to be small, and preferably has a diameter of 11 to 14 mm.
Since the developer-containing container is easy to store and transport and has excellent handleability, it can be detachably attached to a process cartridge, an image forming apparatus, etc., which will be described later, and used for replenishing the developer.

(Image forming apparatus and image forming method)
The image forming apparatus of the present invention includes at least an electrostatic latent image carrier, a charging unit, an exposure unit, a developing unit, a transfer unit, a fixing unit, and a cleaning unit, and further if necessary. And other means appropriately selected, for example, static elimination means, recycling means, control means, and the like. The charging unit and the exposure unit may be collectively referred to as an electrostatic latent image forming unit.

  The image forming method used in the present invention includes at least a charging step, an exposure step, a development step, a transfer step, a fixing step, and a cleaning step, and other steps appropriately selected as necessary, for example, , Including static elimination process, recycling process, control process, etc. The charging process and the exposure process may be collectively referred to as an electrostatic latent image forming process.

  The image forming method used in the present invention can be preferably implemented by the image forming apparatus of the present invention, the charging step can be performed by the charging unit, and the exposure step can be performed by the exposing unit. The developing step can be performed by the developing unit, the transferring step can be performed by the transferring unit, the fixing step can be performed by the fixing unit, and the cleaning step can be performed by the cleaning unit. The other steps can be performed by the other means.

The image forming method used in the present invention is suitable for a full-color image forming method, and it is preferable to employ a tandem electrophotographic image forming process.
In the full-color image forming method, in the secondary transfer step, the linear velocity of transfer of the toner image to the recording medium is 300 mm / sec to 1,000 mm / sec, and the transfer time at the nip portion of the secondary transfer means is 0. It is preferable to set to 5 msec to 20 msec.

<Electrostatic latent image carrier>
There are no particular restrictions on the material, shape, structure, size, etc. of the latent electrostatic image bearing member (hereinafter sometimes referred to as “electrophotographic photosensitive member” or “photosensitive member”). The shape is preferably a drum shape, and examples of the material include inorganic photoconductors such as amorphous silicon and selenium, and organic photoconductors such as polysilane and phthalopolymethine. It is done. Among these, amorphous silicon or the like is preferable in terms of long life.
As the amorphous silicon photoreceptor, for example, a support is heated to 50 ° C. to 400 ° C., and a vacuum deposition method, a sputtering method, an ion plating method, a thermal CVD method, a photo CVD method, a plasma CVD method is applied on the support. A photoconductor having a photoconductive layer made of a-Si (hereinafter sometimes referred to as “a-Si-based photoconductor”) can be used by a film forming method such as the above. Among these, a plasma CVD method, that is, a method in which a source gas is decomposed by direct current, high frequency or microwave glow discharge to form an a-Si deposited film on a support is preferable.

<Charging step and charging means>
The charging step is a step of charging the surface of the electrostatic latent image carrier, and is performed by a charging unit.
The charging can be performed, for example, by applying a voltage to the surface of the electrostatic latent image carrier using the charger.
The charger is not particularly limited and can be appropriately selected according to the purpose. And non-contact chargers using corona discharge such as corotrons and corotrons.

The charging means may take any form such as a magnetic brush or a fur brush in addition to a roller, and can be selected according to the specifications and form of an electrophotographic image forming apparatus. When using a magnetic brush, the magnetic brush is composed of, for example, various ferrite particles such as Zn-Cu ferrite as a charging means, a non-magnetic conductive sleeve for supporting it, and a magnet roll included therein. . Or when using a brush, for example, as the material of the fur brush, a fur treated with carbon, copper sulfide, metal or metal oxide is used, and this is wound around a metal or other conductive core. Make it a charger by sticking.
The charger is not limited to the contact charger as described above, but has an advantage that an image forming apparatus in which ozone generated from the charger is reduced can be obtained.

It is preferable that the charger is disposed in contact or non-contact with the electrostatic latent image carrier and charges the surface of the electrostatic latent image carrier by applying a direct current and an alternating voltage.
Further, the charger is a charging roller having a gap tape on the electrostatic latent image carrier and arranged in a non-contact manner, and the surface of the electrophotographic photosensitive member is applied by applying a direct current and an alternating voltage to the charging roller. Those that are charged are also preferred.
Here, as the charging means, for example, the contact-type charging means shown in FIGS. 1 and 2 can be used.

<< Roller type charging device >>
FIG. 1 shows a schematic configuration of an example of a roller-type charging unit 500 that is a kind of contact-type charging unit. A photoconductor 505 that is a member to be charged is driven to rotate at a predetermined speed (process speed) in the direction of the arrow in FIG. A charging roller 501 serving as a charging unit brought into contact with the photosensitive member 505 is basically composed of a core metal 502 and a conductive rubber layer 503 formed concentrically on the outer periphery of the core metal 502 on the roller. Both ends of the cored bar 502 are rotatably held by a bearing member (not shown) or the like and are pressed against the photosensitive drum by a pressing means (not shown) with a predetermined pressure. In the case of FIG. The photoconductor 505 rotates following the rotational drive. The charging roller 501 is formed to have a diameter of 16 mm by coating a medium resistance conductive rubber layer 503 of about 100,000 Ω · cm on a core metal having a diameter of 9 mm. The cored bar 502 of the charging roller 501 and the illustrated power source 504 are electrically connected, and a predetermined bias is applied to the charging roller 501 by the power source 504. As a result, the peripheral surface of the photoconductor 505 is uniformly charged to a predetermined polarity and potential.

<< Fur brush type charging means >>
The shape of the charging means used in the present invention may take any form such as a magnetic brush type charging means or a fur brush type charging means in addition to the roller type charging means. They can be selected together.
When using the magnetic brush charging means, the magnetic brush is composed of various ferrite particles such as Zn-Cu ferrite as the charging means, a non-magnetic conductive sleeve for supporting the ferrite particles, and a magnet roll included therein. The Or when using a brush-type charging means, for example, as a material of the fur brush, a fur treated with carbon, copper sulfide, metal, and metal oxide is used, and this is treated with a metal or other conductive cored bar. It is used as a charging means by wrapping around or sticking to.
FIG. 2 shows a schematic configuration of an example of the contact-type brush charging unit 510. A photoconductor 515 as an image carrier as a member to be charged is driven to rotate at a predetermined speed (process speed) in the direction of the arrow in FIG. A fur brush roller 511 constituted by a fur brush is brought into contact with the photoreceptor 515 with a predetermined nip width with a predetermined pressing force against the elasticity of the brush portion 513.

The fur brush roller 511 as a contact charging unit in this example is a metal cored bar 512 having a diameter of 6 mm that also serves as an electrode, and a conductive rayon fiber REC-B manufactured by Unitika Co., Ltd. as a brush portion 513 is piled. The tape is wound in a spiral shape to form a roll brush having an outer diameter of 14 mm and a longitudinal length of 250 mm. The brush of the brush part 513 has a density of 300 denier / 50 filaments and 155 brushes per square millimeter.
This roll brush was inserted into a pipe having an inner diameter of 12 mm while rotating in one direction, and the brush and the pipe were set to be concentric, and left in a high-temperature and high-humidity atmosphere to bend and bevel.

The resistance value of the fur brush roller 511 is 1 × 10 ⁵ Ω at an applied voltage of 100V. This resistance value was converted from the current that flows when a fur brush roller is brought into contact with a metal drum having a diameter of 30 mm with a nip width of 3 mm and a voltage of 100 V is applied. The resistance value of the brush-type charging unit 510 is such that, even when a low-voltage defective portion such as a pinhole occurs on the photosensitive member 515 that is a charged body, an excessive leakage current flows into this portion, and the charging nip portion is charged. In order to prevent a defective image from becoming defective, it is necessary to be 10 ⁴ Ω or more, and in order to sufficiently inject charges onto the surface of the photoconductor 515, it is necessary to be 10 ⁷ Ω or less.

  Examples of the material of the brush include REC-C, REC-M1, and REC-M10 other than REC-B manufactured by Unitika Ltd., and SA-7 manufactured by Toray Industries, Inc. Examples include Sanderlon, Beltron manufactured by Kanebo Co., Ltd., Kurabo Industries manufactured by Kuraray Co., Ltd., carbon dispersed in rayon, and global manufactured by Mitsubishi Rayon Co., Ltd. One brush is 3 denier to 10 denier, and preferably has a density of 10 filaments / bundle to 100 filaments / bundle and 80 / mm to 600 strands / mm. The hair foot is preferably 1 mm to 10 mm.

The fur brush roller 511 is rotationally driven at a predetermined peripheral speed (surface speed) in a direction opposite to the rotation direction (counter) of the photoconductor 515 and contacts the photoconductor surface with a speed difference. A predetermined charging voltage is applied to the brush roller 511 from the power source 514, so that the surface of the rotating photoconductor is uniformly contact-charged to a predetermined polarity and potential.
In this example, the contact charging of the photosensitive member 515 by the fur brush roller 511 is performed by direct injection charging, and the surface of the rotating photosensitive member is charged to a potential substantially equal to the charging voltage applied to the fur brush roller 511.

  In addition to the fur brush roller 511, the charging unit used in the present invention may take any form such as a charging roller or a fur brush, and can be selected according to the specifications and form of the image forming apparatus. When using a charging roller, it is common to coat a medium resistance rubber layer of about 100,000 Ω · cm on a cored bar. When using a magnetic brush, the magnetic brush is composed of, for example, various ferrite particles such as Zn-Cu ferrite as a charging means, a non-magnetic conductive sleeve for supporting it, and a magnet roll included therein. .

  As a magnetic brush as the contact charging means, Zn—Cu ferrite particles having an average particle diameter of 25 μm and Zn—Cu ferrite particles having an average particle diameter of 10 μm are mixed at a weight ratio of 1: 0.05, and each average particle is mixed. Magnetic particles having a peak at the diameter position and having ferrite particles with an average particle diameter of 25 μm coated with a medium resistance resin layer were used. The contact charging means is composed of the coated magnetic particles prepared above, a non-magnetic conductive sleeve for supporting the coated magnetic particles, and a magnet roll included therein, and the coated magnetic particles are formed on the sleeve with a thickness of 1 mm. And a charging nip having a width of about 5 mm was formed between the photosensitive member and the photosensitive member. The gap between the magnetic particle holding sleeve and the photosensitive member was about 500 μm. Furthermore, the magnet roll is rotated so that the sleeve surface rubs in the opposite direction at twice as fast as the peripheral speed of the surface of the photosensitive member, and the photosensitive member and the magnetic brush are in uniform contact with each other. I did it.

<Exposure process and exposure means>
The exposure step is a step of exposing the charged electrostatic latent image carrier surface, and is performed by the exposure means.
The exposure can be performed, for example, by exposing the surface of the latent electrostatic image bearing member imagewise using the exposure unit.
The optical system in the exposure is roughly classified into an analog optical system and a digital optical system. The analog optical system is an optical system that projects an original directly onto an electrostatic latent image carrier by an optical system, and the digital optical system receives image information as an electrical signal and converts it into an optical signal. An optical system that exposes an electrophotographic photosensitive member to form an image.

The exposure means is not particularly limited as long as the surface of the latent electrostatic image bearing member charged by the charging means can be exposed like an image to be formed, and is appropriately selected according to the purpose. For example, various exposure devices such as a copying optical system, a rod lens array system, a laser optical system, a liquid crystal shutter optical system, and an LED optical system can be used.
In the present invention, a back light system in which imagewise exposure is performed from the back side of the electrostatic latent image carrier may be employed.

<Development process and development means>
The developing step is a step of developing the electrostatic latent image using the toner or the developer of the present invention to form a visible image.
The visible image can be formed, for example, by developing the electrostatic latent image using the toner or the developer of the present invention, and can be performed by the developing unit. The developing unit is not particularly limited as long as it can be developed using, for example, the toner or the developer of the present invention, and can be appropriately selected from known ones. For example, the toner of the present invention Preferred examples include a developer containing at least a developer, and at least a developing device capable of contacting or non-contacting the toner or the developer with the electrostatic latent image. More preferred is a developing device.

  The developing unit may be a dry developing type, a wet developing type, a single color developing unit, or a multi-color developing unit. For example, a toner having a stirrer for charging the toner or the developer by frictional stirring and a rotatable magnet roller is preferable.

In the developing device, for example, the toner and the carrier are mixed and agitated, and the toner is charged by friction at that time, and held on the surface of the rotating magnet roller in a raised state to form a magnetic brush. . Since the magnet roller is disposed in the vicinity of the electrostatic latent image carrier, a part of the toner constituting the magnetic brush formed on the surface of the magnet roller is electrostatically attracted by the static force. It moves to the surface of the electrostatic latent image carrier. As a result, the electrostatic latent image is developed with the toner, and a visible image is formed with the toner on the surface of the electrostatic latent image carrier.
The developer accommodated in the developing device is a developer containing the toner of the present invention, but the developer may be a one-component developer or a two-component developer. The toner contained in the developer is the toner of the present invention.

  Here, in developing the latent image on the photoreceptor in the present invention, it is preferable to apply an alternating electric field. In the developing device 600 as the developing means shown in FIG. 3, during development, a vibration bias voltage in which an AC voltage is superimposed on a DC voltage is applied to the developing sleeve 601 as a developing bias by the power source 602. The background portion potential and the image portion potential are located between the maximum value and the minimum value of the vibration bias potential. As a result, an alternating electric field whose direction changes alternately is formed in the developing unit 603. In this alternating electric field, the toner and carrier of the developer vibrate vigorously, and the toner 605 flies off the electrostatic binding force to the developing sleeve 601 and the carrier and flies to the photoconductor 604, corresponding to the latent image on the photoconductor. Adhere to. The toner 605 is the toner of the present invention.

  The difference between the maximum value and the minimum value (the peak-to-peak voltage) of the vibration bias voltage is preferably 0.5 kV to 5 kV, and the frequency is preferably 1 kHz to 10 kHz. As the waveform of the vibration bias voltage, a rectangular wave, a sine wave, a triangular wave, or the like can be used. As described above, the DC voltage component of the vibration bias is a value between the background part potential and the image part potential, but the value closer to the background part potential than the image part potential is more likely to cover the background part potential region. This is preferable for preventing toner adhesion.

  When the vibration bias voltage waveform is a rectangular wave, the duty ratio is preferably 50% or less. Here, the duty ratio is a ratio of time during which the toner goes to the photoconductor during one cycle of the vibration bias. By doing so, the difference between the peak value at which the toner is directed to the photoreceptor and the time average value of the bias can be increased, so that the movement of the toner is further activated and the potential of the latent image surface is increased. It can adhere to the distribution and improve the roughness and resolution. In addition, since the difference between the peak value of the carrier having a charge opposite to that of the toner and the time average value of the bias toward the photosensitive member can be reduced, the movement of the carrier is reduced, and the background portion of the latent image is reduced. The probability of carriers adhering to the substrate can be greatly reduced.

<Transfer process and transfer means>
The transfer step is a step of transferring the visible image onto a recording medium. After the primary transfer of the visible image onto the intermediate transfer member using an intermediate transfer member, the visible image is transferred onto the recording medium. A primary transfer step of forming a composite transfer image by transferring a visible image onto an intermediate transfer body using two or more colors, preferably full color toner as the toner, and a composite transfer image; A mode including a secondary transfer step of transferring the transfer image onto the recording medium is more preferable.

The transfer can be performed, for example, by charging the visible latent image using a transfer charger and charging the electrostatic latent image carrier, and can be performed by the transfer unit. The transfer means includes a primary transfer means for transferring a visible image onto an intermediate transfer member to form a composite transfer image, and a secondary transfer means for transferring the composite transfer image onto a recording medium. Embodiments are preferred.
The intermediate transfer member is not particularly limited and may be appropriately selected from known transfer members according to the purpose. For example, a transfer belt and the like are preferable.

The transfer unit (the primary transfer unit and the secondary transfer unit) has at least a transfer unit that peels and charges the visible image formed on the electrostatic latent image carrier to the recording medium side. Is preferred. There may be one transfer means or two or more transfer means. Examples of the transfer device include a corona transfer device using corona discharge, a transfer belt, a transfer roller, a pressure transfer roller, and an adhesive transfer device.
The recording medium is typically plain paper, but is not particularly limited as long as it can transfer an unfixed image after development, and can be appropriately selected according to the purpose. PET for OHP A base or the like can also be used.

Next, the intermediate transfer belt will be described. The intermediate transfer belt is preferably a single resin layer, but may have an elastic layer, a surface layer, or the like as necessary.
There is no restriction | limiting in particular as a resin material which comprises the said resin layer, According to the objective, it can select suitably, For example, a polycarbonate, a fluororesin (ETFE, PVDF), a polystyrene, chloropolystyrene, poly-alpha-methyl Styrene, styrene-butadiene copolymer, styrene-vinyl chloride copolymer, styrene-vinyl acetate copolymer, styrene-maleic acid copolymer, styrene-acrylic acid ester copolymer (styrene-methyl acrylate copolymer) Styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-phenyl acrylate copolymer, etc.), styrene-methacrylic acid ester copolymer (styrene- Methyl methacrylate copolymer, styrene-ethyl methacrylate Polymer, styrene-phenyl methacrylate copolymer, etc.), styrene resin such as styrene-α-methyl acrylate acrylate copolymer, styrene-acrylonitrile-acrylate copolymer, etc. Polymer or copolymer), methyl methacrylate resin, butyl methacrylate resin, ethyl acrylate resin, butyl acrylate resin, modified acrylic resin (silicone modified acrylic resin, vinyl chloride resin modified acrylic resin, acrylic / urethane resin, etc.) , Vinyl chloride resin, styrene-vinyl acetate copolymer, vinyl chloride-vinyl acetate copolymer, rosin modified maleic acid resin, phenol resin, epoxy resin, polyester resin, polyester polyurethane resin, polyethylene, polypropylene, polybutadiene, polyvinyl chloride Den, ionomer resins, polyurethane resins, silicone resins, ketone resins, ethylene - ethyl acrylate copolymer, xylene resin, polyvinyl butyral resin, polyamide resin and modified polyphenylene oxide resins. These may be used individually by 1 type and may use 2 or more types together.

  There is no restriction | limiting in particular as an elastic material (elastic material rubber, elastomer) which comprises the said elastic layer, According to the objective, it can select suitably, For example, a butyl rubber, a fluorine-type rubber, an acrylic rubber, EPDM, NBR, acrylonitrile -Butadiene-styrene rubber, natural rubber, isoprene rubber, styrene-butadiene rubber, butadiene rubber, ethylene-propylene rubber, ethylene-propylene terpolymer, chloroprene rubber, chlorosulfonated polyethylene, chlorinated polyethylene, urethane rubber, syndiotactic 1 , 2-Polybutadiene, epichlorohydrin rubber, silicone rubber, fluorine rubber, polysulfide rubber, polynorbornene rubber, hydrogenated nitrile rubber, thermoplastic elastomer (for example, polystyrene, polyolefin, polyvinyl chloride) , Polyurethane, polyamide, polyurea, polyester, fluorocarbon resin) and the like. These may be used individually by 1 type and may use 2 or more types together.

  The material for the surface layer is not particularly limited and may be appropriately selected depending on the intended purpose. However, a material that increases the secondary transferability by reducing the adhesion force of the toner to the surface of the intermediate transfer belt is required. For example, materials that use one or more of polyurethane, polyester, epoxy resin, etc. to reduce surface energy and increase lubricity, such as fluororesin, fluorine compound, fluorocarbon, titanium dioxide, silicon carbide, etc. These powders and particles can be used by dispersing one type or two or more types or particles having different particle sizes. Further, it is also possible to use a material having a reduced surface energy by forming a fluorine-rich layer on the surface by heat treatment, such as a fluorine-based rubber material.

  A resistance value adjusting conductive agent is added to the resin layer and the elastic layer. The resistance value adjusting conductive agent is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include metal powders such as carbon black, graphite, aluminum, and nickel; tin oxide, titanium oxide, antimony oxide, Conductive metal oxides such as indium oxide, potassium titanate, antimony oxide-tin oxide composite oxide (ATO), indium oxide-tin oxide composite oxide (ITO); conductive metal oxides include barium sulfate and silicic acid It may be coated with insulating fine particles such as magnesium and calcium carbonate.

<Fixing process and fixing means>
The fixing step is a step of fixing the toner image transferred to the recording medium, and can be fixed using a fixing unit. When two or more color toners are used, the toner may be fixed each time the toner of each color is transferred to the recording medium, or the toner of all colors may be transferred to the recording medium and fixed in a stacked state. Also good. The fixing unit is not particularly limited, and a heat fixing method using a known heating and pressing unit can be employed. Examples of the heating and pressing means include a combination of a heating roller and a pressure roller, and a combination of a heating roller, a pressure roller, and an endless belt. At this time, heating temperature is 80 degreeC-200 degreeC normally. If necessary, for example, a known optical fixing device may be used together with the fixing means.

Here, as the fixing unit, for example, the fixing unit shown in FIG. 4 can be used. The fixing unit shown in FIG. 4 includes a heating roller 710 that is heated by electromagnetic induction of the induction heating unit 760, a fixing roller (opposite rotating body) 720 that is arranged in parallel with the heating roller 710, a heating roller 710, and a fixing roller 720. And an endless belt-like fixing belt (heat-resistant belt, toner heating medium) 730 that is heated by a heating roller 710 and rotates in the direction of arrow A by at least one of these rollers, and a fixing belt 730 And a pressure roller (pressure rotator) 740 that is pressed against the fixing roller 720 and rotates in the forward direction with respect to the fixing belt 730.
The heating roller 710 is made of, for example, a hollow cylindrical magnetic metal member such as iron, cobalt, nickel, or an alloy of these metals, and has an outer diameter of, for example, 20 mm to 40 mm, and a thickness of, for example, 0.3 mm to 1.0 mm. As a result, the temperature rises quickly with a low heat capacity.

  The fixing roller (opposite rotating body) 720 includes, for example, a metal core 721 made of stainless steel or the like, and an elastic member 722 in which a heat resistant silicone rubber is solid or foamed and covered with the core 721. . In order to form a contact portion having a predetermined width between the pressure roller 740 and the fixing roller 720 by the pressing force from the pressure roller 740, the outer diameter is set to about 20 mm to 40 mm, which is larger than the heating roller 710. . The elastic member 722 has a thickness of about 4 to 6 mm. With this configuration, the heat capacity of the heating roller 710 is smaller than the heat capacity of the fixing roller 720, so that the heating roller 710 is rapidly heated and the warm-up time is shortened.

The fixing belt 730 stretched between the heating roller 710 and the fixing roller 720 is heated at a contact portion W1 with the heating roller 710 heated by the induction heating unit 760. The inner surface of the fixing belt 730 is continuously heated by the rotation of the heating roller 710 and the fixing roller 720, and as a result, the entire belt is heated. FIG. 5 shows a layer structure of the fixing belt 730. The fixing belt 730 has the following four layers from the inner layer to the surface layer.
Substrate 731: Resin layer of polyimide (PI) resin, etc. Heating layer 732: Conductive material layer such as Ni, Ag, SUS, etc. Intermediate layer 733: Elastic layer for uniform fixing Release layer of fluororesin material for oil-less

  The thickness of the release layer 734 is preferably 10 μm to 300 μm, and particularly preferably 200 μm. When such a fixing belt 730 is used, the surface of the fixing belt 730 sufficiently wraps the toner image T formed on the recording medium 770 in the fixing unit 700 as shown in FIG. It becomes possible to melt by heating. The thickness of the release layer 734, that is, the surface release layer, needs to be at least 10 μm in order to ensure wear resistance over time. Further, when the thickness of the release layer 734 is larger than 300 μm, the heat capacity of the fixing belt 730 increases and the time required for warm-up becomes longer. Further, the surface temperature of the fixing belt 730 is hardly lowered in the toner image fixing step, and the aggregation effect of the melted toner at the fixing portion outlet is not obtained, and the releasability of the fixing belt 730 is lowered, and the toner image T The toner adheres to the fixing belt 730 and so-called hot offset occurs. The heat generating layer 732 made of the metal may be used as the base of the fixing belt 730, but a heat-resistant resin such as a fluorine resin, a polyimide resin, a polyamide resin, a polyamideimide resin, a PEEK resin, a PES resin, or a PPS resin. Layers may be used.

  The pressure roller 740 includes, for example, a metal core 741 made of a metal cylindrical member having high thermal conductivity such as copper or aluminum, and an elastic material having high heat resistance and toner releasability provided on the surface of the metal core 741. And a member 742. In addition to the metal, SUS may be used for the core metal 741. The pressure roller 740 presses the fixing roller 720 via the fixing belt 730 to form the fixing nip portion N, but in this embodiment, the pressure roller 740 is harder than the fixing roller 720. As a result, the pressure roller 740 bites into the fixing roller 720 (and the fixing belt 730), and the recording medium 770 follows the circumferential shape of the surface of the pressure roller 740 due to this biting, so that the recording medium 770 becomes the fixing belt 730. It has the effect of facilitating separation from the surface. The outer diameter of the pressure roller 740 is about 20 to 40 mm, which is the same as that of the fixing roller 720, but the wall thickness is about 0.5 mm to 2.0 mm, which is thinner than the fixing roller 720.

  As shown in FIG. 4, the induction heating means 760 that heats the heating roller 710 by electromagnetic induction has an excitation coil 761 that is a magnetic field generation means, and a coil guide plate 762 around which the excitation coil 761 is wound. Yes. The coil guide plate 762 has a semi-cylindrical shape disposed close to the outer peripheral surface of the heating roller 710, and the exciting coil 761 is formed by passing a long exciting coil wire along the coil guide plate 762 in the axial direction of the heating roller 710. It is one that is wound around alternately. The exciting coil 761 has an oscillation circuit connected to a drive power source (not shown) whose frequency is variable. Outside the exciting coil 761, a semi-cylindrical exciting coil core 763 made of a ferromagnetic material such as ferrite is fixed to the exciting coil core support member 764 and is disposed in proximity to the exciting coil 761.

<Cleaning process and cleaning means>
The cleaning step is a step of removing the toner remaining on the electrostatic latent image carrier and can be suitably performed by a cleaning unit.
The cleaning means is not particularly limited as long as it can remove the electrophotographic toner remaining on the electrostatic latent image carrier, and can be appropriately selected from known cleaners. Suitable examples include brush cleaners, electrostatic brush cleaners, magnetic roller cleaners, blade cleaners, brush cleaners, web cleaners, and the like.

<Other processes and other means>
-Static elimination process and static elimination means-
The neutralization step is a step of performing neutralization by applying a neutralization bias to the electrostatic latent image carrier, and can be suitably performed by a neutralization unit.
The neutralization means is not particularly limited, and may be appropriately selected from known neutralizers as long as it can apply a neutralization bias to the electrostatic latent image carrier. Preferably mentioned.

-Recycling process and recycling means-
The recycling step is a step of recycling the toner removed by the cleaning step to the developing unit, and can be suitably performed by the recycling unit.
There is no restriction | limiting in particular as said recycling means, A well-known conveyance means etc. are mentioned.

-Control process and control means-
The control step is a step of controlling each of the steps, and can be suitably performed by a control unit.
The control means is not particularly limited as long as the movement of each means can be controlled, and can be appropriately selected according to the purpose. Examples thereof include devices such as a sequencer and a computer.

<Full-color image forming method and image forming apparatus>
As the full-color image forming apparatus as the image forming apparatus of the present invention, for example, the tandem image forming apparatus 100 shown in FIG. 6 can be used.
In FIG. 6, an image forming apparatus 100 includes an image writing unit (120Bk, 120C, 120M, 120Y), an image forming unit (130Bk, 130C, 130M, 130Y), and a paper feeding unit for performing color image formation by electrophotography. 140 is mainly composed. Based on the image signal, an image processing unit (not shown) performs image processing, and converts it into black (Bk), cyan (C), magenta (M), and yellow (Y) color signals for image formation, It transmits to an image writing part (120Bk, 120C, 120M, 120Y). The image writing unit (120Bk, 120C, 120M, 120Y) is, for example, a laser scanning optical system including a laser light source, a deflector such as a rotary polygon mirror, a scanning imaging optical system, and a mirror group (none of which are shown). There are four writing optical paths corresponding to the respective color signals, and image writing corresponding to the respective color signals is performed in the image forming units (130Bk, 130C, 130M, and 130Y).

  The image forming unit (130Bk, 130C, 130M, 130Y) includes photoconductors (210Bk, 210C, 210M, 210Y) for black, cyan, magenta, and yellow, and photoconductors (210Bk, 210C, 210M, 210Y) is usually an organic photoreceptor (OPC). Around each photoconductor (210Bk, 210C, 210M, 210Y), there is a charging means (215Bk, 215C, 215M, 215Y), and an exposure unit for laser light from the image writing unit (120Bk, 120C, 120M, 120Y). Developing means for each color (200Bk, 200C, 200M, 200Y), primary transfer means (230Bk, 230C, 230M, 230Y), cleaning means (300Bk, 300C, 300M, 300Y), static eliminator (not shown), etc. It is arranged. The developing means (200Bk, 200C, 200M, 200Y) uses a two-component magnetic brush developing system. Further, an intermediate transfer belt (220) is interposed between each photoconductor (210Bk, 210C, 210M, 210Y) and primary transfer means (230Bk, 230C, 230M, 230Y). The toner images of each color are sequentially superimposed and transferred to carry the toner image on each photoconductor. __ In some cases, it is preferable that a pre-transfer charger as pre-transfer charging means is disposed outside the intermediate transfer belt 220 at a position after passing through the primary transfer position of the final color and before passing through the secondary transfer position. . This pre-transfer charger uniformly transfers the toner image to the same polarity as the toner image before transferring the toner image on the intermediate transfer belt 220 transferred to the photosensitive member 210 in the primary transfer portion onto a transfer sheet as a recording medium. It is charged.

  The toner image on the intermediate transfer belt 220 transferred from each photoconductor (210Bk, 210C, 210M, 210Y) includes a halftone portion and a solid portion, or includes portions having different amounts of toner overlap. The charge amount may vary. Further, there may be a case where the charge amount varies in the toner image on the intermediate transfer belt 220 after the primary transfer due to the peeling discharge generated in the gap adjacent to the downstream side of the primary transfer portion in the intermediate transfer belt moving direction. Such variation in the charge amount in the same toner image lowers the transfer margin in the secondary transfer portion that transfers the toner image on the intermediate transfer belt 220 onto the transfer paper. Therefore, the toner image before being transferred to the transfer paper by the pre-transfer charger is uniformly charged to the same polarity as the toner image, thereby eliminating the variation in the charge amount in the same toner image and the transfer margin at the secondary transfer portion. Has improved.

  As described above, according to this image forming method, the toner image on the intermediate transfer belt 220 transferred from each photoconductor (210Bk, 210C, 210M, 210Y) is uniformly charged by the pre-transfer charger, thereby the intermediate transfer belt 220. Even if there is a variation in the charge amount in the upper toner image, the transfer characteristics in the secondary transfer portion can be made substantially constant over the respective portions of the toner image on the intermediate transfer belt 220. Therefore, it is possible to suppress a decrease in transfer margin when transferring to transfer paper and to stably transfer a toner image.

  In this image forming method, the amount of charge charged by the pre-transfer charger varies depending on the moving speed of the intermediate transfer belt 220 that is the object to be charged. For example, if the moving speed of the intermediate transfer belt 220 is slow, the time for the same portion of the toner image on the intermediate transfer belt 220 to pass through the charging region by the pre-transfer charger becomes long, and the charge amount increases. Conversely, when the moving speed of the intermediate transfer belt 220 is fast, the charge amount of the toner image on the intermediate transfer belt 220 becomes small. Therefore, when the moving speed of the intermediate transfer belt 220 changes while the toner image on the intermediate transfer belt 220 passes through the charging position by the pre-transfer charger, the transfer speed depends on the moving speed of the intermediate transfer belt 220. Therefore, it is preferable to control the pre-transfer charger so that the charge amount with respect to the toner image does not change during the process.

  Conductive rollers 241, 242, and 243 are provided between the primary transfer means (230Bk, 230C, 230M, and 230Y). The transfer sheet is fed from the sheet feeding unit 140 and is then carried by the transfer belt 180 via the registration roller pair 160. The intermediate transfer belt 170 and the transfer belt 180 come into contact with each other, and the intermediate transfer is performed by the secondary transfer roller 170. The toner image on the belt 220 is transferred to transfer paper, and color image formation is performed.

Then, the transfer paper after the image formation is conveyed to the fixing unit 150 by the secondary transfer belt 180, and the image is fixed to obtain a color image. The toner on the intermediate transfer belt 220 remaining without being transferred is removed from the belt by an intermediate transfer belt cleaning unit (not shown).
Since the toner polarity on the intermediate transfer belt 220 before transfer onto the transfer paper is the same negative polarity as during development, a positive transfer bias voltage is applied to the secondary transfer roller 170, and the toner is transferred onto the transfer paper. The The nip pressure at this portion affects the transfer property and greatly affects the fixability. Further, the toner on the intermediate transfer belt 220 remaining without being transferred is discharged and charged to the positive polarity side and charged to 0 to the positive side at the moment when the transfer paper and the intermediate transfer belt 220 are separated. Note that the toner image formed when the transfer paper is jammed or in the non-image area is not affected by the secondary transfer, and thus remains of negative polarity.

  The thickness of the photosensitive layer is 30 μm, the beam spot diameter of the optical system is 50 μm × 60 μm, and the light quantity is 0.47 mW. The developing process is performed by setting the charging (exposure side) potential V0 of the photoconductor (black) 210Bk to −700 V, the post-exposure potential VL to −120 V, the developing bias voltage to −470 V, that is, the developing potential 350 V. The visible image of the toner (black) formed on the photoconductor (black) 210Bk is then transferred (intermediate transfer belt and transfer paper) and completed as an image through a fixing process. First, all colors are transferred from the primary transfer means (230Bk, 230C, 230M, 230Y) to the intermediate transfer belt 220, and then transferred onto a transfer sheet by applying a bias to another secondary transfer roller 170.

  Next, the photoconductor cleaning means will be described in detail. In FIG. 6, each developing means (200Bk, 200C, 200M, 200Y) and each cleaning means (300Bk, 300C, 300M, 300Y) are connected by toner transfer pipes (250Bk, 250C, 250M, 250Y), respectively. (Dashed line in FIG. 6). Each toner transfer pipe (250Bk, 250C, 250M, 250Y) contains a screw (not shown), and the toner collected by each cleaning means (300Bk, 300C, 300M, 300Y) It is transferred to each developing means (200Bk, 200C, 200M, 200Y).

  In the conventional direct transfer method using the combination of the four photosensitive drums and the belt conveyance, paper dust adheres when the photoreceptor and the transfer paper come into contact with each other, and the paper dust is contained when the toner is collected. The image was deteriorated such as toner missing and could not be used. Furthermore, in the conventional system combining a single photoconductor drum and intermediate transfer, the use of an intermediate transfer member eliminates paper dust adhesion to the photoconductor during transfer paper transfer, but recycling of residual toner on the photoconductor In practice, it is practically impossible to separate the mixed color toners. There is also a proposal to use a mixed color toner as a black toner, but even if all the colors are mixed, it does not become black, and the color changes depending on the print mode. Therefore, it is impossible to recycle the toner with one photoconductor configuration.

  On the other hand, in this full-color image forming apparatus, since the intermediate transfer belt 220 is used, paper dust is less mixed and paper dust is prevented from adhering to the intermediate transfer belt 220 during paper transfer. Since each photoconductor (210Bk, 210C, 210M, 210Y) uses an independent color toner, each photoconductor cleaning means (300Bk, 300C, 300M, 300Y) does not need to be contacted or separated, and only the toner is reliably collected. can do. The positively charged toner remaining on the intermediate transfer belt 220 is cleaned by a conductive fur brush 262 to which a negative voltage is applied. The method of applying a voltage to the conductive fur brush 262 is exactly the same as the conductive fur brush 261 except that the polarity is different. The toner remaining without being transferred is also almost cleaned by the two conductive fur brushes 261 and 262. Here, toner, paper powder, talc, and the like remaining without being cleaned by the conductive fur brush 262 are negatively charged by the negative voltage of the conductive fur brush 262. The next black primary transfer is a transfer using a positive voltage, and negatively charged toner or the like is attracted to the intermediate transfer belt 220 side, so that the transfer to the photoreceptor (black) 210Bk side can be prevented.

  FIG. 7 shows another example of the image forming apparatus of the present invention, which is a tandem indirect transfer type electrophotographic image forming apparatus 900. In FIG. 7, 910 is an image forming apparatus main body, 950 is a paper feed table on which it is placed, 940 is a scanner mounted on the image forming apparatus main body 910, and 400 is an automatic document feeder (ADF) further mounted thereon. The image forming apparatus main body 910 is provided with an endless belt-shaped intermediate transfer member 50 at the center. As shown in FIG. 7, in this example, it is wound around three support rollers 14, 15, 16 and can be rotated and conveyed clockwise in the figure. In FIG. 7, an intermediate transfer member cleaning means 17 for removing residual toner remaining on the intermediate transfer member 50 after image transfer is provided to the left of the second support roller 15 among the three. Further, among the three images, four images of yellow, cyan, magenta, and black are arranged on the intermediate transfer member 50 stretched between the first support roller 14 and the second support roller 15 along the conveyance direction. The tandem image forming unit 920 is configured by arranging the forming units 18 side by side.

  An exposure unit 21 is further provided on the tandem image forming unit 920 as shown in FIG. On the other hand, a secondary transfer unit 22 is provided on the opposite side of the intermediate transfer member 50 from the tandem image forming unit 920. In the illustrated example, the secondary transfer unit 22 is configured by suspending a secondary transfer belt 24 that is an endless belt between two rollers 23 and pressing the secondary transfer unit 22 against the third support roller 16 via an intermediate transfer member 50. The image on the intermediate transfer member 50 is transferred to a sheet. Next to the secondary transfer means 22, a fixing means 25 for fixing the transferred image on the sheet is provided. The fixing unit 25 is configured by pressing a pressure roller 27 against a fixing belt 26 which is an endless belt. The secondary transfer unit 22 described above is also provided with a sheet conveyance function for conveying the sheet after image transfer to the fixing unit 25. Of course, a transfer roller or a non-contact charger may be disposed as the secondary transfer unit 22, and in such a case, it is difficult to provide this sheet conveyance function together. In the example of FIG. 7, sheet reversal is performed under such a secondary transfer unit 22 and fixing unit 25 to invert the sheet so as to record images on both sides of the sheet in parallel with the tandem image forming unit 920 described above. A device 28 is provided.

Now, when making a copy using this color electrophotographic apparatus, a document is set on a document table 930 of the automatic document feeder 400. Alternatively, the automatic document feeder 400 is opened, a document is set on the contact glass 32 of the scanner 940, and the automatic document feeder 400 is closed and pressed.
When a start switch (not shown) is pressed, when the document is set on the automatic document feeder 400, the document is transported and moved onto the contact glass 32, and then the document is set on the other contact glass 32. At that time, the scanner 940 is immediately driven, and the first traveling body 33 and the second traveling body 34 travel. Then, the first traveling body 33 emits light from the light source and further reflects the reflected light from the document surface toward the second traveling body 34 and is reflected by the mirror of the second traveling body 34 and passes through the imaging lens 35. The document is placed in the reading sensor 36 and the original content is read.

  When a start switch (not shown) is pressed, one of the support rollers 14, 15 and 16 is rotationally driven by a drive motor (not shown), the other two support rollers are driven to rotate, and the intermediate transfer member 50 is rotated and conveyed. To do. At the same time, the individual image forming means 18 rotate the photoconductor to form black, yellow, magenta, and cyan monochrome images on each photoconductor. Then, along with the conveyance of the intermediate transfer member 50, these single color images are sequentially transferred to form a composite color image on the intermediate transfer member 50.

On the other hand, when a start switch (not shown) is pressed, one of the paper feed rollers 142 of the paper feed table 950 is selectively rotated, and a sheet is fed out from one of the paper feed cassettes 144 provided in multiple stages in the paper bank 143 to separate the separation roller 145. Are separated one by one into the paper feed path 146, transported by the transport roller 147, guided to the paper feed path 148 in the image forming apparatus 900, and abutted against the registration roller 49 and stopped.
Alternatively, the sheet feeding roller 142 is rotated to feed out the sheets on the manual feed tray 51, separated one by one by the separation roller 58, put into the manual sheet feeding path 53, and abutted against the registration roller 49 and stopped.
Then, the registration roller 49 is rotated in synchronization with the composite color image on the intermediate transfer member 50, the sheet is fed between the intermediate transfer member 50 and the secondary transfer unit 22, and is transferred by the secondary transfer unit 22. A color image is recorded on the sheet.

  The sheet after the image transfer is conveyed by the secondary transfer means 22 and sent to the fixing means 25. The fixing means 25 applies heat and pressure to fix the transferred image, and then the switching claw 55 is used to switch the discharge roller. The paper is discharged at 56 and stacked on the paper discharge tray 57. Alternatively, it is switched by the switching claw 55 and put into the sheet reversing device 28, where it is reversed and guided again to the transfer position, and an image is recorded also on the back surface, and then discharged onto the discharge tray 57 by the discharge roller 56. On the other hand, the intermediate transfer member 50 after image transfer is removed by the intermediate transfer member cleaning unit 17 to remove residual toner remaining on the intermediate transfer member 50 after the image transfer, and is prepared for re-image formation by the tandem image forming unit 920. Here, the registration roller 49 is generally used while being grounded, but it is also possible to apply a bias for removing paper dust from the sheet.

<Process cartridge>
The process cartridge used in the present invention uses an electrostatic latent image carrier that carries an electrostatic latent image and an electrostatic latent image carried on the electrostatic latent image carrier using the toner of the present invention. A developing means for developing and forming a visible image, and further having other means such as a charging means, a developing means, a transfer means, a cleaning means, and a static elimination means, which are appropriately selected as necessary. Thus, it can be attached to and detached from the image forming apparatus main body.

The developing means includes a developer container that contains the toner or developer of the present invention, and a developer carrier that carries and transports the toner or developer contained in the developer container. And a layer thickness regulating member for regulating the thickness of the toner layer to be carried. The process cartridge of the present invention can be detachably mounted on various electrophotographic image forming apparatuses, facsimile machines, and printers, and is preferably detachably mounted on the image forming apparatus of the present invention.
An example of the process cartridge is shown in FIG.
The process cartridge 800 shown in FIG. 8 includes a photoreceptor 801, a charging unit 802, a developing unit 803, and a cleaning unit 806.

  The operation of the process cartridge 800 will be described. The photosensitive member 801 is rotationally driven at a predetermined peripheral speed. In the rotating process, the photosensitive member 801 is uniformly charged with a positive or negative predetermined potential on its peripheral surface by the charging unit 802, and then image exposure light from an image exposure unit (not shown) such as slit exposure or laser beam scanning exposure. In this way, an electrostatic latent image is sequentially formed on the peripheral surface of the photoreceptor 801, and the formed electrostatic latent image is then transferred to a developer 804 and a developing roller 805 accommodated in a developer container of the developing unit 803. The toner image formed and developed by the transfer unit is transferred to a recording medium fed from the sheet feeding unit between the photosensitive member 801 and a transfer unit (not shown) in synchronization with the rotation of the photosensitive member 801 by the transfer unit. Sequentially transferred. The recording medium that has received the image transfer is separated from the surface of the photosensitive member, introduced into an image fixing means (not shown), and fixed on the image, and printed out as a copy (copy). The surface of the photoconductor 801 after the image transfer is cleaned by the removal of the transfer residual toner by the cleaning unit 806, and after being further discharged, it is repeatedly used for image formation.

  Examples of the present invention will be described below, but the present invention is not limited to these examples.

(Production Example 1)
<Preparation of toner base particles 1>
-Synthesis of crystalline polyester resin 1-
1,10-decanedioic acid 2,300 g, 1,8-octanediol 2,530 g, and hydroquinone 4 in a 5-liter four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer, and a thermocouple Then, the mixture was reacted at 180 ° C. for 8 hours, heated to 215 ° C., reacted for 3 hours, and further reacted at 8.3 kPa for 2 hours to synthesize [Crystalline Polyester Resin 1].
The obtained [crystalline polyester resin 1] had a DSC peak temperature of 70 ° C., a weight average molecular weight Mw of 13,000, a number average molecular weight Mn of 3,200, and an Mw / Mn of 3.5 as measured by GPC. It was.

-Synthesis of amorphous polyester (unmodified polyester) resin 1-
In a 5-liter four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer, and a thermocouple, 229 parts by mass of bisphenol A ethylene oxide 2 mol adduct, 529 parts by mass of bisphenol A propylene oxide 3 mol adduct , 100 parts by mass of isophthalic acid, 108 parts by mass of terephthalic acid, 46 parts by mass of adipic acid, and 2 parts by mass of dibutyltin oxide were reacted at 220 ° C. for 8 hours under normal pressure, and further for 5 hours at a reduced pressure of 10 mmHg to 15 mmHg. After that, 30 parts by mass of trimellitic anhydride was put in a reaction vessel and reacted at 180 ° C. for 3 hours under normal pressure to synthesize [Amorphous Polyester Resin 1].
The obtained [Amorphous polyester resin 1] had a number average molecular weight of 1,600, a weight average molecular weight of 4,800, a glass transition temperature (Tg) of 55 ° C., and an acid value of 17 mgKOH / g.

-Synthesis of prepolymer-
In a reaction vessel equipped with a cooling tube, a stirrer, and a nitrogen introduction tube, 682 parts by mass of bisphenol A ethylene oxide 2 mol adduct, 81 parts by mass of bisphenol A propylene oxide 2 mol adduct, 283 parts by mass of terephthalic acid, 22 parts by mass of merit acid and 2 parts by mass of dibutyltin oxide were added, reacted at 230 ° C. for 8 hours under normal pressure, and further reacted for 5 hours at a reduced pressure of 10 mmHg to 15 mmHg to obtain [Intermediate Polyester Resin 1].
The obtained [Intermediate polyester resin 1] had a number average molecular weight of 2,100, a weight average molecular weight of 9,500, a glass transition temperature (Tg) of 55 ° C., an acid value of 0.5 mgKOH / g, and a hydroxyl value of 51 mgKOH / g. It was.
Next, 410 parts by mass of [Intermediate Polyester Resin 1], 89 parts by mass of isophorone diisocyanate, and 500 parts by mass of ethyl acetate are placed in a reaction vessel equipped with a cooling pipe, a stirrer, and a nitrogen introduction pipe. The reaction was performed for a while to obtain [Prepolymer 1]. [Prepolymer 1] obtained had a free isocyanate mass% of 1.53%.

-Synthesis of ketimine-
In a reaction vessel equipped with a stirrer and a thermometer, 170 parts by mass of isophoronediamine and 75 parts by mass of methyl ethyl ketone were charged and reacted at 50 ° C. for 5 hours to obtain [ketimine compound 1]. The amine value of the obtained [ketimine compound 1] was 418.

-Preparation of masterbatch (MB)-
1,200 parts by weight of water, C.I. I. Pigment Blue 15: 3 (manufactured by Dainichi Seika Co., Ltd.) 540 parts by mass and [Amorphous Polyester Resin 1] 1,200 parts by mass are added and mixed with a Henschel mixer (manufactured by Mitsui Mining Co., Ltd.). After kneading at 80 ° C. for 30 minutes, the mixture was cooled by rolling and pulverized with a pulverizer to obtain [Masterbatch Cy].

-Preparation of oil phase-
In a container equipped with a stir bar and a thermometer, 378 parts by mass of the above [Amorphous polyester resin 1], 110 parts by mass of paraffin wax (HNP-51, manufactured by Nippon Seiwa Co., Ltd.) as a release agent, CCA, salicylic acid metal complex E-84, manufactured by Orient Chemical Industry Co., Ltd.), 22 parts by weight, and 947 parts by weight of ethyl acetate were charged, heated to 80 ° C. with stirring, held at 80 ° C. for 5 hours, and then in 1 hour. Cooled to 30 ° C.
Next, 500 parts by mass of [Masterbatch Cy] and 500 parts by mass of ethyl acetate were charged into the container and mixed for 1 hour to obtain [Raw material solution 1].
1,324 parts by mass of the obtained [raw material solution 1] was transferred to a container, and using a bead mill (Ultra Visco Mill, manufactured by Imex Co., Ltd.), the liquid feeding speed was 1 kg / hr, the disk peripheral speed was 6 m / sec, and the diameter was 0. Filled with 80% by volume of 5 mm zirconia beads, the pigment and wax were dispersed under conditions of 3 passes.
Next, 1042.3 parts by mass of a 65% by mass ethyl acetate solution of [Amorphous Polyester Resin 1] was added, followed by one pass with a bead mill under the above conditions to obtain [Pigment / Wax Dispersion 1]. The obtained [Pigment / Wax Dispersion 1] had a solid content of 50% by mass.

-Preparation of dispersion of crystalline polyester-
In a metal 2 L container, 100 parts by mass of [Crystalline Polyester Resin 1] and 400 parts by mass of ethyl acetate were heated and dissolved at 75 ° C., and then rapidly cooled in an ice-water bath at a rate of 27 ° C./min. . To this, 500 mL of glass beads (diameter 3 mm) was added, and pulverized for 10 hours with a batch type sand mill (manufactured by Campehapio) to obtain [Crystalline Polyester Dispersion 1].

-Synthesis of organic fine particle emulsion-
In a reaction vessel in which a stir bar and a thermometer are set, 683 parts by mass of water, 11 parts by mass of an ethylene oxide adduct sulfate sulfate salt (Eleminol RS-30, manufactured by Sanyo Chemical Industries, Ltd.), 138 parts by mass of styrene Then, 138 parts by weight of methacrylic acid and 1 part by weight of ammonium persulfate were charged and stirred at 400 rpm for 15 minutes, whereby a white emulsion was obtained. The system was heated to raise the system temperature to 75 ° C. and reacted for 5 hours. Further, 30 parts by mass of a 1% by mass ammonium persulfate aqueous solution was added, and the mixture was aged at 75 ° C. for 5 hours, and an aqueous dispersion of a vinyl resin (a copolymer of styrene-methacrylic acid-methacrylic acid ethylene oxide adduct sulfate sodium salt). [Fine particle dispersion 1] was obtained.
The volume average particle diameter of the obtained [fine particle dispersion 1] measured by a particle size distribution analyzer (LA-920, manufactured by Horiba Seisakusho) was 0.14 μm. A portion of the obtained [fine particle dispersion 1] was dried to isolate the resin component.

-Preparation of aqueous phase-
990 parts by weight of water, 83 parts by weight of [Fine Particle Dispersion 1], 37 parts by weight of a 48.5% by weight aqueous solution of sodium dodecyl diphenyl ether disulfonate (Eleminol MON-7, manufactured by Sanyo Chemical Industries), and 90 parts by weight of ethyl acetate The mixture was stirred to obtain a milky white liquid. This is designated as [Aqueous Phase 1].

-Emulsification and solvent removal-
[Pigment / Wax Dispersion 1] 664 parts by mass, [Prepolymer 1] 109.4 parts by mass, [Crystalline Polyester Dispersion 1] 73.9 parts by mass, and [Ketimine Compound 1] 4.6 A mass part is put in a container, and after mixing for 1 minute at 5,000 rpm using a TK homomixer (manufactured by Tokushu Kika Co., Ltd.), 1,200 parts by mass of the [aqueous phase 1] is added to the container, and then the TK homomixer is used. The mixture was mixed for 20 minutes at a rotational speed of 13,000 rpm to obtain [Emulsion slurry 1].
Next, [Emulsion slurry 1] is put into a container in which a stirrer and a thermometer are set, and after removing the solvent at 30 ° C. for 8 hours, aging is performed at 45 ° C. for 4 hours to obtain [dispersed slurry 1]. It was.

-Cleaning and drying-
100 parts by mass of the obtained [Dispersion Slurry 1] was filtered under reduced pressure, and then washed and dried as follows.
(1): 100 parts by mass of ion-exchanged water was added to the filter cake, mixed with a TK homomixer (rotation speed: 12,000 rpm for 10 minutes), and then filtered.
(2): 100 parts by mass of a 10% by mass aqueous sodium hydroxide solution was added to the filter cake of (1), mixed with a TK homomixer (30 minutes at 12,000 rpm), and then filtered under reduced pressure.
(3): 100 parts by mass of 10 mass% hydrochloric acid was added to the filter cake of (2), mixed with a TK homomixer (10 minutes at 12,000 rpm), and then filtered.
(4): Add 300 parts by mass of ion-exchanged water to the filter cake of (3), mix with a TK homomixer (rotation speed 12,000 rpm for 10 minutes), and then filter twice to perform [Filter cake 1]. Obtained.
The obtained [Filtration cake 1] was dried at 45 ° C. for 48 hours with a circulating drier and sieved with a mesh of 75 μm to obtain [Toner base particle 1].
Next, volume average particle diameter Dv and average circularity of the produced toner base particles 1 were measured as follows. The toner base particle 1 has a volume average particle diameter Dv of 5.3 and an average circularity of 0.965.

<Measurement of Volume Average Particle Size Dv of Toner Base Particles>
The volume average particle diameter Dv of the toner base particles is measured by a PC-9801 personal computer (manufactured by NEC) via an interface (manufactured by Nikka Giken) that outputs the number distribution and volume distribution to a Coulter Multisizer III type measuring device. Were connected, and the particle size distribution was measured.
Specifically, first, 0.1 mL to 5 mL of a surfactant (alkyl benzene sulfonate) was added as a dispersant to 100 mL to 150 mL of the electrolytic solution. In addition, electrolyte solution prepared 1 mass% aqueous solution using 1st grade sodium chloride, and ISOTON-II (Coulter company make) was used.

Next, 2 mg to 20 mg of the sample was added and suspended, and then dispersed with an ultrasonic disperser for 1 minute to 3 minutes. The volume and number of toners were measured from the obtained dispersion using a 100 μm aperture, and the volume distribution and number distribution were calculated.
As a channel, it is 2.00 micrometers or more and less than 2.52 micrometers; 2.52 micrometers or more and less than 3.17 micrometers; 3.17 micrometers or more and less than 4.00 micrometers; 4.00 micrometers or more and less than 5.04 micrometers; 5.04 micrometers or more and less than 6.35 micrometers; .35 μm or more and less than 8.00 μm; 8.00 μm or more and less than 10.08 μm; 10.08 μm or more and less than 12.70 μm; 12.70 μm or more and less than 16.00 μm; 16.00 μm or more and less than 20.20 μm; Less than 40 μm; 25.40 μm or more and less than 32.00 μm; 3 channels of 32.00 μm or more and less than 40.30 μm are used, and particles having a particle size of 2.00 μm or more and less than 40.30 μm are targeted.

<Measurement of average circularity>
The average circularity of the toner is measured using a flow type particle image analyzer (“FPIA-2100”, manufactured by Sysmex Corporation), and is performed using analysis software (FPIA-2100 Data Processing Program for FPIA version 00-10). It was.
First, 0.1% to 0.5 mL of 10% by mass surfactant (alkylbenzene sulfonate, Neogen SC-A, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) is added to a 100 mL glass beaker, and 0.1 g of each toner is added. Add ~ 0.5 g and stir with microspatel. Next, 80 mL of ion exchange water was added, and the obtained dispersion was dispersed for 3 minutes with an ultrasonic disperser (manufactured by Honda Electronics Co., Ltd.), and then the concentration of the dispersion was adjusted using the FPIA-2100. The shape and distribution of the toner were measured until 5,000 / μL to 15,000 / μL were obtained.

Example 1
-Preparation of toner-
-[Toner base particle 1] 100 parts by mass-1.0 part by mass of hydrophobic silica particles C (RY-200S, manufactured by Nippon Aerosil Co., Ltd., primary average particle diameter 16 nm)
Hydrophobic silica particle A 1.0 part by mass (RY-50, manufactured by Nippon Aerosil Co., Ltd., primary average particle size 40 nm)
・ 0.5 parts by mass of titanium oxide particles (MT-150, manufactured by Teica, primary average particle size of 15 nm)
The toner composition was charged into a Henschel mixer (Henschel 20B, manufactured by Mitsui Mining Co., Ltd.), and the hydrophobic silica particles A (external additive 1) were added at 2,600 rpm in a state where the temperature in the tank was maintained at 25 ° C to 30 ° C. For 5 minutes (first stage mixing). After completion of mixing, the titanium oxide particles (external additive 2) were continuously added at 2,600 rpm for 5 minutes with the Henschel mixer (Henschel 20B, manufactured by Mitsui Mining Co., Ltd.) while maintaining the temperature in the tank at 25 ° C to 30 ° C. Mixed (2nd stage mixing). After the completion of mixing, the hydrophobic silica particles C (external additive 3) were continuously added at 3,000 rpm with the Henschel mixer (Henschel 20B, manufactured by Mitsui Mining Co., Ltd.) in a state where the temperature in the tank was maintained at 25 ° C. to 30 ° C. Mix for 30 minutes (3rd stage mixing). After mixing, the toner of Example 1 was produced by sieving with a sieve having an aperture of 36 μm using an ultrasonic vibration device (TMS-50, manufactured by Tokuju Seisakusho). The tank temperature is the temperature of the powder in the mixer, and was confirmed by measuring the temperature in the tank.

-Image formation-
An image was formed under the following conditions using an apparatus modified so that the linear speed of the developing roller in the developing machine of the image forming apparatus (Ricoh MP C305SP, manufactured by Ricoh Co., Ltd.) could be changed. Unless otherwise specified, the developer capacity was 110 g, and the linear velocity of the developing roller in the developing machine was 266 mm / sec.
0% to less than 10,000 sheets at 23 ° C, 50% RH, 10,000 sheets to less than 20,000 sheets at 28 ° C, 85% RH, 20,000 sheets to less than 30,000 sheets at 15 ° C The image area ratio 5% image and the image area ratio 20% image were alternately output every 1,000 sheets under the condition of 30% RH. Up to 90,000 images were created in three sets for this actual machine.

(Examples 2 to 11 and Comparative Examples 1 to 4)
-Preparation of toner-
In Example 1, inorganic fine particles corresponding to external additive 1, external additive 2, and external additive 3 were used in the types and amounts shown in Table 2, and the third stage mixing (mixing of external additive 3) was performed in Table 3. Toners of Examples 2 to 11 and Comparative Examples 1 to 4 were produced in the same manner as in Example 1 except that the mixing conditions shown in (1) were changed (the number of revolutions, the mixing time, and the temperature in the tank was 25-30 ° C.). .
-Image formation-
In Example 1, an image was formed in the same manner as in Example 1 except that the linear velocity of the developing roller and the developer capacity were the values shown in Table 3.

[Evaluation method]
<Calculation method of external additive coverage>
The coverage of the external additive (inorganic fine particles) on the toner base particles was calculated by the following equation.
H = Σ (√3 × Dv × Pt / (2π · da · Pa) × Ca × 100)
In the above formula, Dv is the volume average particle diameter of the toner base particles, Pt is the true specific gravity of the toner base particles, da is the primary average particle diameter of the external additive, Pa is the true specific gravity of the external additive, and Ca is in the toner. This represents the content (%) of the external additive.
When there are a plurality of external additives, the primary average particle diameter da, the true specific gravity Pa, and the content Ca are obtained for each external additive, the individual coverage is calculated, and these are totaled. The overall coverage was determined.

<< Primary average particle diameter of external additive >>
The primary average particle diameter of the external additive was measured by dispersing a primary particle in a solvent (tetrahydrofuran (THF)) and then removing the solvent on the substrate to dry the sample, using a field emission scanning electron microscope ( FE-SEM, acceleration voltage: 5 kV to 8 kV, observation magnification: 8,000 times to 10,000 times) Measure the average value of the particle diameter of the external additive in the field of view (measured number of particles: 100) Was determined by

<< Primary average particle diameter of free external additive >>
The measurement was performed in the same manner as the measurement of the primary average particle diameter of the external additive except that particles released by the method for measuring the liberation rate of the external additive described later were used.

<< Average circularity of free external additive >>
The following measurement was performed using particles (silica) released by the method for measuring the liberation rate of the external additive described later.
Image analysis was performed on 100 free particles, and the circularity of each photographed external additive particle was determined by the following formula, and the average of these values was defined as the average circularity.
Circularity = circle equivalent diameter perimeter / perimeter = [2 × (Aπ) ^1/2 ] / PM
In the above formula, A represents the projected area of the external additive particles, and PM represents the perimeter of the external additive particles.
The average circularity is a true sphere when 1.0, and the lower the numerical value, the higher the irregularity having irregularities on the outer periphery.
〔Evaluation criteria〕
○: The average circularity of free particles is 0.5 or more and less than 0.9 Δ: The average circularity of free particles is 0.9 or more

<Measurement method of liberation rate of external additive>
The liberated amount of the external additive (hydrophobic silica particles) was measured as follows.
(1) To 200 mL ointment bottle, add 100 mL of ion-exchanged water and 4.4 mL of 33% by mass of a dry well aqueous solution (trade name: Drywell, manufactured by Fuji Film Co., Ltd.) containing surfactant, and mix well. Then, 5 g of toner was added to the obtained mixed solution, mixed well by hand shaking 30 times, and allowed to stand for 1 hour or more.
(2) Next, after stirring by hand shaking 20 times, using an ultrasonic homogenizer (trade name: homogenizer, model VCX750, CV33, manufactured by SONICS & MATERIALS Co., Ltd.), a dial is set at an output of 50% for 1 minute under the following conditions. Ultrasonic energy was applied and dispersed.
-Ultrasonic conditions-
・ Vibration time: 60 seconds continuous ・ Amplitude: 20 W (30%)
・ Vibration start temperature: 23 ℃ ± 1.5 ℃
(3) The obtained dispersion is centrifuged for 2 minutes at 2000 rpm with a centrifuge (product name: desktop multi-centrifuge H-40F, manufactured by KOKUSAN), and the supernatant is discarded.
(4) The obtained solid content is again dispersed in 60 ml of ion exchange water, suction filtered with a filter paper (trade name: qualitative filter paper (No. 2, 110 mm), manufactured by Advantech Toyo Co., Ltd.), and again 2 with ion exchange water. The toner was dried after washing twice, filtering, removing the free external additive.
(5) The amount of the external additive of the toner before and after the removal of the external additive was quantified by a fluorescent X-ray method (ZSX-100e, manufactured by Rigaku Corporation) to determine the free amount of the external additive.
In the fluorescent X-ray method, the amount of free hydrophobic silica particles was determined by measuring Si.

From the value of the external additive amount of the toner before and after the dispersion measured by the methods (1) to (5), the liberation rate (% by mass) of the external additive was obtained by the following (Formula 1). .
(Formula 1)
Release rate = [(mass of external additive before dispersion−mass of residual additive after dispersion) / mass of external additive before dispersion] × 100

<Evaluation of heat-resistant storage stability>
10 mg of the toner was weighed, each toner was filled in a 20 ml glass bottle, tapped the glass bottle 100 times, and allowed to stand in a constant temperature layer set at a temperature of 55 ° C. and a humidity of 80% for 24 hours. The penetration (%) of this toner was measured by a penetration test (JIS K2235-1991). The toner stored in a low-temperature and low-humidity environment (10 ° C., 15%) was similarly evaluated for penetration, and the value with the lower penetration was used in a high-temperature, high-humidity, low-temperature, low-humidity environment. In addition, it shows that heat resistance preservability is excellent, so that the value of the said penetration is large.
[Evaluation criteria]
◎: Needle penetration is 25 mm or more ○: Needle penetration is 15 mm or more and less than 25 mm ×: Needle penetration is less than 15 mm

<Evaluation of charging characteristics>
In a test room at a temperature of 20 ° C. and a humidity of 50%, 100 parts of the carrier and 5 parts of the toner of the present invention were charged into a stainless steel pot and rotated and mixed on a ball mill frame at a constant rotational speed. The developer charge amount (μC / g) 10 minutes after the start of rotation was measured by a blow-off device.
[Evaluation criteria]
A: Charge amount is -20 to -35 μc / g
○: Charge amount is −10 to −20, −35 to −45 μc / g
X: Charge amount is outside the above range

<Durability evaluation>
Using an image forming apparatus provided with the belt fixing device shown in FIG. 9, an image is evaluated by modifying an image forming apparatus (“IPSIO Color 8100”; manufactured by Ricoh Co., Ltd.) into an oilless fixing method and tuning it. A solid image having an adhesion amount of each developer of 0.4 ± 0.1 mg / cm 2 was formed on a transfer paper (“Type 6000”; manufactured by Ricoh Co., Ltd.) at a fixing roller surface temperature of 160 ± 2 ° C. . The image density of arbitrary three places in the obtained solid image was measured using a spectrometer (“938 Spectrodensitometer”; manufactured by X-Rite). The average value of the image densities at the three locations was used as the image density value.
Next, using the image forming apparatus, after running 100,000 image charts with a 35% image area, a solid image in which the amount of each developer adhered to the transfer paper is 0.4 ± 0.1 mg / cm 2 is obtained. The surface temperature of the fixing roller was 160 ± 2 ° C. The image density of arbitrary three places in the obtained solid image was measured using the spectrometer. The average value of the image density values at the three locations was used as the image density value.
[Evaluation criteria]
A: Difference between image density values before running and after running is less than 0.1 B: Difference between image density values before running and after running is less than 0.5, 0.1 or more ×: Before running and after running Difference in image density value of 0.5 or more

<Evaluation of environmental fluctuation rate>
The environmental fluctuation rate was measured using the following formula.
Environmental fluctuation rate = (LL environment charge)-(HH environment charge)} / [{(LL environment charge) + (HH environment charge)} / 2]
The LL environmental charge was measured as follows.
In a test room at a temperature of 10 ° C. and a humidity of 15%, 100 parts of the carrier and 5 parts of the toner of the present invention were charged in a stainless steel pot and rotated and mixed on a ball mill frame at a constant rotational speed. The charge amount (μC / g) of the developer 5 minutes after the start of rotation was measured with a blow-off device.
The HH environmental charge was measured as follows.
In a test room at a temperature of 40 ° C. and a humidity of 90%, 100 parts of the carrier and 5 parts of the toner of the present invention were charged in a stainless steel pot and rotated and mixed on a ball mill frame at a constant rotational speed. The charge amount (μC / g) of the developer 5 minutes after the start of rotation was measured with a blow-off device.
[Evaluation criteria]
◎: Environmental change rate 95% or less ○: Environmental change rate 100% or less, 95% or more ×: Environmental change rate 100% or more

<Evaluation of low-temperature fixability>
A dot image and a solid image were output for every 10,000 sheets, the presence or absence of image peeling, and the residual ratio of the image density before and after rubbing the solid image with a pad were determined, and the low-temperature fixability was evaluated according to the following criteria. The image density was measured with X-Rite 938 (manufactured by X-RITE).
〔Evaluation criteria〕
○: No image peeling and a residual ratio of image density of 85% or more Δ: No peeling of the image, residual ratio of image density of 70% to less than 85% ×: Image peeling and a residual ratio of image density of 70% Less than

<Evaluation of toner scattering>
After the completion of the 90,000 image formation, the cover of the image forming apparatus was opened, and the degree of toner contamination in the image forming apparatus was visually observed and evaluated according to the following criteria.
〔Evaluation criteria〕
○: No significant toner contamination △: Toner contamination has occurred, but no toner contamination is seen on the outside of the cover ×: Toner contamination can be confirmed on the outside of the cover. Scattering occurs

<Evaluation of photoconductor shaving>
After the completion of the 90,000 image formation, the photoreceptor was observed and the occurrence of an abnormal image in the dot image was confirmed and evaluated according to the following criteria.
Photoreceptor scraping means a state in which the photoconductor is scratched by toner or the like, and if it is severe, the circumferential direction of the photoconductor is shaved.
〔Evaluation criteria〕
○: No photoconductor scraping Δ: Photoconductor scraping occurred, but no difference was detected in the dot image ×: Photoconductor was scratched, and the difference was clearly detected in the dot image

<Comprehensive evaluation>
As a comprehensive evaluation, a case where all items were ○ was judged as ◎, a case where there was one or more Δ, but there was no problem in use, ○, and a case where x was one or more was judged as ×.

59 Charger 60 Cleaning means (cleaning blade)
DESCRIPTION OF SYMBOLS 61 Developing device 62 Transfer charging device 63 Photoconductor cleaning means 80 Transfer roller 90 Cleaning means 100A, 100B, 100C Image forming apparatus 110 Belt-type fixing means 121 Heating roller 122 Fixing roller 123 Fixing belt 124 Pressure roller 125 Heating source 126 Cleaning roller 127 Temperature sensor 150 Fixing means 200Bk, 200C, 200M, 200Y Developing means 215Bk, 215C, 215M, 215Y Charging means 220 Intermediate transfer belt 300Bk, 300C, 300M, 300Y Cleaning means 500 Roller-type charging means 505 Photoconductor 510 Brush-type charging means 515 photoconductor 600 developing device 603 developing unit 604 photoconductor 605 toner 770 recording medium 800 process cartridge 801 photoconductor 802 charging Means 803 Development means 804 Developer 805 Development roller 806 Cleaning means 900 Image forming apparatus

JP 2006-30654 A JP2013-156430A JP 2012-128195 A

Claims (4)

An electrostatic latent image carrier, a charging unit that charges the surface of the electrostatic latent image carrier, an exposure unit that exposes the charged electrostatic latent image carrier to form an electrostatic latent image, and the electrostatic latent image carrier. A toner used in an image forming apparatus having a developing unit that develops an image with toner to form a visible image,
In the image forming apparatus, the linear velocity of the developing roller in the developing unit is A [mm / sec],
When the developer capacity in the developing means is B [g], A and B satisfy the following relational expression (1):
2.2 ≦ A / B ≦ 2.6 (1)
The toner has hydrophobic silica particles as an external additive, and the liberation rate of the hydrophobic silica particles in the toner is 3 to 15% by mass.   The toner according to claim 1, wherein a liberation rate of the hydrophobic silica particles in the toner is 5 to 11% by mass.   The toner according to claim 1, wherein an average circularity of the released hydrophobic silica particles is 0.5 or more and 0.9 or less.   The toner according to claim 1, wherein the liberated hydrophobic silica particles have a volume average particle diameter of 10 nm to 2 μm.

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