JPH08227171A - Toner for developing electrostatic charge image - Google Patents

Abstract

PURPOSE: To obtain a toner excellent in transferability and cleanability, less liable to the deterioration of additives and excellent in durability after use in repeated many times. CONSTITUTION: This toner consists essentially of toner particles having 1-9μm wt. average particle diameter, inorg. fine powder made hydrophobic and having 10-90nm average particle diameter and fine silicon compd. powder made hydrophobic. The average particle diameter of the silicon compd. powder is 30-120nm and the powder contains silicon compd. particles each having 5-30nm particle diameter by 15-45% by number, silicon compd. particles each having 30-60nm particle diameter by 30-70% by number and silicon compd. particles each having >=60nm particle diameter by 5-45% by number.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic charge image developing toner used in electrophotography or electrostatic recording.

[0002]

2. Description of the Related Art US Pat.
A large number of methods are known as described in Japanese Patent No. 7,691, Japanese Patent Publication No. 42-23910 and Japanese Patent Publication No. 43-24748. Generally, a photoconductive substance is used to form an electrostatic charge image on a photoconductor by various means, and then the electrostatic charge image is developed with a toner, and if necessary, a toner image is formed on a transfer material such as paper. After transferring the
A copy is obtained by fixing with pressure, heat and pressure, or solvent vapor. The toner remaining on the photoconductor without being transferred is cleaned by various methods, and then the above steps are repeated. As a cleaning unit, a blade cleaning unit having a structure in which a cleaning blade made of a rubber elastic material is brought into pressure contact with a photosensitive member is widely used because it is simple and small in structure, and is advantageous in terms of cost.

In recent years, such an image forming apparatus has begun to be used not only as an office copying machine for copying an original document but also as a printer as an output of a computer or a personal copy for personal use.

In addition to the printer field typified by laser beam printers, the development of plain paper fax is also rapidly developing.

Therefore, small size, light weight, high image quality and high reliability are required. As a result, the performance required of the toner becomes higher, and it is desired to improve the performance of the toner.

As one of means for achieving high image quality,
There is also a method of reducing the particle size of the toner, but as the particle size of the toner is reduced, the toner easily slips between the photoconductor and the cleaning blade, and cleaning failure easily occurs. Therefore, there are methods such as increasing the contact pressure between the photoconductor and the cleaning blade, and increasing the friction coefficient between the photoconductor and the cleaning member by changing the cleaning member. When the blade is arranged to face the moving direction of the photoconductor, the blade is likely to be turned over. Further, with the durability of many sheets, a phenomenon such as scratches or filming on the surface of the photoconductor and deterioration of image quality due to the scratches easily occurs.

It is desired for a toner to have both a small particle size for high image quality and a cleaning property for high reliability.

Further, since the toner having a small particle size has a large triboelectric charge amount and is difficult to be transferred, the transferability of the toner image from the surface of the photoconductor to the transfer material is improved, or the transfer from the surface of the photoconductor to the intermediate transfer material is prevented. Improving the transferability of the toner image in the transfer process from the intermediate transfer body to the transfer material is important for improving the image quality and reducing the load of the cleaning process.

In Japanese Patent Application Laid-Open No. 60-32060 (corresponding US Pat. No. 4,626,487), an inorganic fine powder having a large BET specific surface area and an inorganic fine powder having a small BET specific surface area are mixed with toner particles. Have been proposed for use. However, as the particle size of the toner is reduced, a toner having a better transfer property and cleaning property is desired.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to provide a toner for developing an electrostatic charge image which solves the above problems.

An object of the present invention is to provide an electrostatic charge image developing toner which is excellent in durability of a large number of sheets.

An object of the present invention is to provide a toner for developing an electrostatic charge image having high transfer efficiency.

An object of the present invention is to provide a toner for developing an electrostatic charge image which is excellent in cleaning property.

An object of the present invention is to provide a toner for developing an electrostatic charge image, in which deterioration of the external additive is small when a large number of sheets are durable.

[0015]

According to the present invention, (a) toner particles having a weight average particle diameter of 1 to 9 μm and (b) an average particle diameter of 10 are used.
A toner for developing an electrostatic charge image comprising at least a hydrophobicized inorganic fine powder having a particle size of about 90 nm and a hydrophobicized silicon compound fine powder (c), wherein the hydrophobicized silicon compound fine powder has an average particle size of 30-120 nm, particle size 5-3
Containing 15 to 45% by number of 0 nm silicon compound particles,
30 to 70% by number of silicon compound particles having a particle size of 30 to 60 nm are contained, and 5 silicon compound particles having a particle size of 60 nm or more are included.
The present invention relates to a toner for developing an electrostatic charge image, characterized in that the toner contains about 45% by number.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS There is a method of making toner particles small as a means for improving the image quality. However, when the toner particles have a small particle diameter and the average particle diameter becomes small, the fluidity is higher than that of toner particles having a large average particle diameter. And the transfer rate in the transfer step tends to decrease. Therefore, a fluidity improver such as silica fine powder is used to improve the fluidity of toner particles having a small average particle size. The toner particles having deteriorated properties are not consumed but are accumulated in the developing device, and as a result, the quality of the toner tends to be deteriorated.
Further, in the cleaning process, it is difficult to remove toner particles having a small average particle size from an electrostatic image carrier such as a photoconductor by a cleaning member such as a cleaning blade or a cleaning roller for a long period of time. Is likely to occur.

In the present invention, the weight average particle diameter is 1 to 9 μm.
m toner particles with a mean particle size of 10 to 10 as a fluidity improver.
Add 90 nm hydrophobized inorganic fine powder, and
In order to maintain the effect of adding the hydrophobized inorganic fine powder for a long period of time, the average particle size is 30 to 120 nm, and the silicon compound particles having a particle size of 5 to 30 nm are contained in an amount of 15 to 45% by number.
30 containing silicon compound particles having a particle size of 30 to 60 nm
Further, a hydrophobized silicon compound fine powder having a broad particle size distribution and containing silicon compound particles having a particle size of 60 nm or more and 5 to 45% by number is further added.

The toner particles used in the present invention have a weight average diameter of 1 to 9 μm in order to faithfully develop an analog latent image or minute latent image dots in order to improve the image quality.
(Preferably 2 μm to 8 μm). Further, the variation coefficient (A) in the number distribution of the toner particles is preferably 35% or less. In the case of toner particles having a weight average diameter of less than 1 μm, a large amount of toner particles remain after transfer on an electrostatic image holding member such as a photoconductor or an intermediate transfer member due to a decrease in transfer efficiency. It is not preferable as the toner used in the present invention because it tends to cause uneven unevenness. When the weight average diameter of the toner particles exceeds 9 μm, the toner particles are likely to be fused to the surface of the photoconductor, the intermediate transfer material or the like. If the variation coefficient in the number distribution of toner particles exceeds 35%, the tendency becomes stronger.

The particle size distribution of toner particles can be measured by various methods. In the present invention, a Coulter counter is used.

For example, a Coulter Counter TA-II type (manufactured by Coulter) or a Coulter Multisizer (manufactured by Coulter) is used as a measuring device, and an interface (manufactured by Nikkaki Co., Ltd.) for outputting number distribution and volume distribution and CX-1 Personal are used. The computer (manufactured by Canon) is maintained, and the electrolyte is approximately 1% NaC using primary sodium chloride.
Prepare an aqueous solution. For example, ISOTON II (manufactured by Coulter Scientific Japan) can be used. The measuring method is 100 to 150 ml of the electrolytic aqueous solution.
0.1-5 ml of a surfactant (preferably alkylbenzene sulfonate) is added as a dispersant, and 2-20 mg of a measurement sample is further added. The electrolytic solution in which the sample is suspended is dispersed by an ultrasonic disperser for about 1 to 3 minutes, and, for example, 100 μaperture or 50 μaperture is used as an aperture by the Coulter Counter TA-II type, and the number is 2 based on the number. The particle size distribution of ~ 40μ (or 1-20μ) particles is measured and the value according to the invention is then determined.

Coefficient of variation A in the number distribution of toner particles
Is calculated from the following formula.

Coefficient of variation A = [S / D ₁ ] × 100 [wherein S represents a standard deviation value in the number distribution of toner particles, and D ₁ represents the number average particle diameter (μm) of the toner particles.
Indicates. ]

Examples of the binder resin used in the toner of the present invention include commonly used styrene- (meth) acrylic copolymers, polyester resins, epoxy resins, and styrene-butadiene copolymers. In the method of directly obtaining toner particles by a polymerization method, a monomer for forming them is used. Specifically, styrene; o
Styrene-based monomers such as (m-, p-)-methylstyrene and m (p-)-ethylstyrene; methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, (meth ) Butyl acrylate, octyl (meth) acrylate, dodecyl (meth) acrylate, stearyl (meth) acrylate, behenyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, (meth)
(Meth) acrylic acid ester type monomers such as dimethylaminoethyl acrylate and diethylaminoethyl (meth) acrylate; ene type monomers such as butadiene, isoprene, cyclohexene, (meth) acrylonitrile and acrylic acid amide are preferably used. To be These may be used alone or generally in the publication Polymer Handbook Second Edition III-P 139-192 (John Wiley).
& Sons) glass transition temperature (Tg)
However, it is used by appropriately mixing the monomers so as to show 40 to 75 ° C. When the theoretical glass transition temperature is lower than 40 ° C, problems tend to occur from the viewpoint of storage stability and durability stability of the toner, while when it exceeds 75 ° C, the fixing point of the toner is increased. Particularly, in the case of a color toner for forming a full-color image, the color mixing property of each color toner at the time of fixing is deteriorated, the color reproducibility is poor, and the transparency of the OHP image is deteriorated, which is not preferable.

The molecular weight of the binder resin is measured by gel permeation chromatography (GPC). In the case of a toner having a core-shell structure, specific GPC
The toner can be extracted by using a Soxhlet extractor with a toluene solvent for 20 hours in advance, and then the toluene is distilled off with a rotary evaporator to obtain an extract. The low softening point substance is dissolved but the outer shell is dissolved. An organic solvent that does not dissolve the resin (such as chloroform) is added to the extract and thoroughly washed, and then the residue is treated with tetrahydrofuran (TH
Sample (THF solution) obtained by filtering the solution dissolved in F) with a solvent resistant membrane filter having a pore size of 0.3 μm.
Is measured using 150C manufactured by Waters. The column configuration is Showa Denko A-801, 802, 803, 80.
4,805,806,807 can be connected and a molecular weight distribution can be measured using the calibration curve of a standard polystyrene resin. The number average molecular weight (Mn) of the obtained resin component is 5000 to 1.0
0,000 is preferable, and the ratio (Mw / Mn) of the weight average molecular weight (Mw) and the number average molecular weight (Mn) is 2 to 100.
The binder resin having the following formula is preferable in the present invention.

The colorants used in the present invention include the following yellow colorants, magenta colorants and cyan colorants. Black colorants include carbon black, magnetic materials or the following yellow colorants / magenta colorants. / A black color mixture is used by mixing a cyan colorant.

As the yellow colorant, condensed azo compounds, isoindolinone compounds, anthraquinone compounds,
Compounds represented by azo metal complexes, methine compounds and allylamide compounds are used. Specifically, C.I. I. Pigment Yellow 12, 13, 14, 15, 17, 6
2, 74, 83, 93, 94, 95, 109, 110,
111, 128, 129, 147, 168, 180 etc. are used suitably.

As the magenta colorant, a condensed azo compound, a diketopyrrolopyrrole compound, an anthraquinone, a quinacridone compound, a basic dye lake compound, a naphthol compound, a benzimidazolone compound, a thioindigo compound and a perylene compound are used. Specifically, C.I.
I. Pigment Red 2, 3, 5, 6, 7, 23, 4
8; 2, 48; 3, 48; 4, 57; 1, 81; 1, 1
44, 146, 166, 169, 177, 184, 18
5,202,206,220,221,254 are particularly preferred.

As the cyan colorant, a copper phthalocyanine compound and its derivative, an anthraquinone compound, a basic dye lake compound and the like can be used. Specifically, C.I. I.
Pigment Blue 1, 7, 15, 15: 1, 15: 2,
15: 3, 15: 4, 60, 62, 66 and the like can be used particularly preferably.

These colorants may be used alone or in combination, and may be used in the form of solid solution. The colorant is a hue,
It is selected in terms of saturation, brightness, weather resistance, OHP transparency, and dispersibility in toner particles. The amount of the colorant added is preferably 1 to 20 parts by weight based on 100 parts by weight of the resin component.

When a magnetic material is used as the black colorant, unlike other colorants, it is 40% by weight with respect to 100 parts by weight of the resin.
It is preferable to use ˜150 parts by weight.

The charge control agent used in the present invention includes:
Known ones can be used. A charge control agent that is colorless and can increase the charging speed of the toner and can stably maintain a constant charge amount is preferable. Further, when the toner particles are directly polymerized, a charge control agent having no polymerization inhibitory property and having no solubilized product in the aqueous dispersion medium is particularly preferable. Specific compounds include, as negative charge control agents, metal compounds of aromatic carboxylic acids such as salicylic acid, naphthoic acid, and dicarboxylic acid; polymeric compounds having a sulfonic acid or carboxylic acid group in the side chain; boron compound; urea Compounds; silicon compounds; currys arenes and the like. Examples of the positive charge control agent include a quaternary ammonium salt; a polymer type compound having the quaternary ammonium salt in its side chain; a guanidine compound; an imidazole compound. The charge control agent is resin 10
It is preferable to use 0.5 to 10 parts by weight with respect to 0 parts by weight. However, the addition of the charge control agent is not essential in the present invention, in the case of using the two-component developing method, utilizing the triboelectric charging with the carrier, in the case of using the non-magnetic one-component blade coating developing method,
By positively utilizing the triboelectric charging with the blade member or the sleeve member, it is not always necessary to include the charge control agent in the toner particles.

In order to improve the fixing property and anti-offset property of the toner, it is preferable to add a release agent to the toner particles. As the release agent, a low softening point compound having a softening point of 40 to 150 ° C. is preferable, and further, ASTM D
A compound having a main body endothermic maximum peak value (melting point) in a DSC curve measured according to 3418-8 in the range of 30 to 120 ° C (more preferably 40 to 90 ° C) is preferable. If the maximum peak value is less than 30 ° C., the self-aggregating force of the release agent becomes weak, and as a result, the high temperature offset resistance becomes weak, which is not preferable. On the other hand, if the maximum peak value exceeds 120 ° C., the fixing temperature becomes high, and it becomes difficult to properly smooth the surface of the fixed image, which is not preferable from the viewpoint of deterioration of color mixture. Furthermore, when toner particles are obtained by a direct polymerization method, granulation and polymerization are carried out in an aqueous medium, and therefore, if the temperature of the maximum endothermic peak value is high, the release agent mainly precipitates during granulation, which is preferable. Absent.

To measure the temperature (melting point) of the maximum peak value of the release agent, for example, DSC-7 manufactured by Perkin Elmer Co. is used. The melting point of indium and zinc is used to correct the temperature of the device detection unit, and the heat of fusion of indium is used to correct the amount of heat. An aluminum pan is used as a sample, an empty pan is set as a control, and measurement is performed at a temperature rising rate of 10 ° C./min.

As the releasing agent, paraffin wax, polyolefin wax, polymethylene wax such as Fischer-Tropsch wax, amide wax, higher fatty acid, higher fatty acid metal salt, long-chain alkyl alcohol, ester wax and derivatives thereof (for example, These graft compounds or block compounds, etc.) can be mentioned.

Further, as the toner to be mounted on the full-color copying machine, it is necessary that the color toners are sufficiently mixed in the fixing step, which improves the color reproducibility and OH.
The transparency of the P image is important, and it is generally preferable to use a sharp melt and low molecular weight resin for the color toner as compared with the black toner. For a normal black toner, a release agent having relatively high crystallinity represented by polyethylene wax or polypropylene wax is used in order to improve high temperature offset resistance at the time of fixing. However, in the full-color toner, the transparency of the OHP toner image is impaired due to the crystallinity of the release agent. Therefore, silicone oil or the like is uniformly applied to the heat fixing roller without adding a release agent as a constituent component of the color toner, and as a result, the high temperature offset resistance is improved. However, since the transfer material having the toner-fixed image thus obtained has extra silicone oil or the like adhered to the surface thereof, it causes unpleasant feeling when used by the user, which is not preferable.

Therefore, in the case of color toners, as the release agent, a long-chain alkyl group having 10 or more (preferably 18 or more) carbon atoms which does not impair the transparency of OHP and has high temperature offset resistance is used. Ester waxes having three or more (preferably two or more) are preferable.

In recent years, the need for full-color double-sided images has been increasing, and when forming a double-sided image, the transfer paper having the toner image formed on the front side is first fixed when the image is formed on the back side. Since the toner passes through the heating portion of the container again, it is necessary to more fully consider the high temperature offset resistance of the toner. Therefore, in the present invention, it is preferable to add a release agent. Specifically, it is preferable to use 5 to 40 parts by weight, and more preferably 10 to 40 parts by weight of the release agent per 100 parts by weight of the binder resin. If it is added in an amount of less than 5 parts by weight, the high temperature offset resistance is lowered, and further, the image on the back surface tends to show an offset phenomenon during the fixing of double-sided images. If the amount is more than 40 parts by weight, during the production of the toner, for example, the fusion of the toner is likely to occur in the apparatus during the production by the pulverization method, and the toner particles are likely to coalesce during the granulation during the production by the polymerization method. Those with a wide particle size distribution are easy to generate.

As a method for producing the toner particles used in the present invention, a resin, a release agent composed of a low softening point substance, a colorant, a charge control agent and the like are uniformly used in a pressure kneader, an extruder or a media disperser. And then mechanically or in a jet stream to collide with the target to finely pulverize it to the desired toner particle size (if necessary, a step of smoothing and spheroidizing the toner particles is added), and then further classifying In addition to the method of producing a toner by a pulverization method in which the toner has a sharp particle size distribution through the steps, Japanese Patent Publication No. 56-1394.
No. 5, etc., a method of atomizing a molten mixture into air using a disk or a multi-fluid nozzle to obtain spherical toner, JP-B-36-10231, and JP-A-59-53856.
Japanese Patent Laid-Open No. 59-61842 and a method for directly producing a toner by using the suspension polymerization method,
For the dispersion polymerization method that directly produces a toner using an aqueous organic solvent that is soluble in the monomer and is insoluble in the obtained polymer, or the soap-free polymerization method that produces a toner by directly polymerizing in the presence of a water-soluble polar polymerization initiator. It is possible to produce a toner using a representative emulsion polymerization method or the like.

In the present invention, in order to further improve the transferability of the toner, the toner particles preferably have a shape factor SF-1 of 100 to 150 (more preferably 100 to 14).
0, more preferably 100 to 130), and the shape factor SF-2 is preferably 100 to 140 (more preferably 100 to 130, further preferably 100 to 125).
It is preferred that Toner particle shape factor SF-1
When SF-2 approaches 100, the additive externally added to the toner particles is easily embedded in the toner particle surface,
Although the effect of addition tends to decrease, as in the present invention, an additive such as a fluidity improver externally added to the toner particles by externally adding a hydrophobized silicon compound fine powder having a specific particle size distribution. It is possible to satisfactorily suppress the deterioration.

In the present invention, SF-1 indicating the shape factor
Is, for example, Hitachi FE-SEM (S-800)
100 toner images magnified 500 times by using a sampler are randomly sampled, and the image information is, for example, an image analysis device (Luzex manufactured by Nicore Co.) via an interface.
III) is introduced and analyzed, and the value calculated by the following formula is defined as the shape factor SF-1.

[0041]

[Equation 1]

[Wherein MXLNG represents the absolute maximum length of the toner particles, and AREA represents the projected area of the toner particles. ]

Further, the shape factor SF-2 is a value obtained by calculation from the following formula.

[0044]

[Equation 2]

[In the formula, PERI represents the perimeter of the toner particles, and AREA represents the projected area of the toner particles. ]

As shown in FIG. 8A, the shape factor SF-1
Indicates the degree of roundness of toner particles, and as shown in FIG. 8B, the shape factor SF-2 indicates the degree of unevenness of toner particles.

The toner particles produced by the melt-kneading-pulverization method are indefinite, and the shape factor SF-of the toner particles is usually
1 exceeds 150, and the shape factor SF-2 is 1
It is over 40.

When a full-color copying machine that transfers a plurality of toner images after development is used, the amount of toner on the photoconductor increases as compared with the case of one color black toner used in a black-and-white copying machine. It is difficult to improve the transfer efficiency only by using the regular toner. Further, in the case of using a usual irregular toner, between the photoconductor and the cleaning member, between the intermediate transfer member and the cleaning member, and /
Alternatively, due to the shearing force or the rubbing force between the photoconductor and the intermediate transfer body, toner fusion or filming occurs on the surface of the photoconductor or the intermediate transfer body, and the transfer efficiency is likely to deteriorate. In the generation of a full-color image, it is difficult to transfer toner images of four colors uniformly, and when an intermediate transfer member is used, problems such as color unevenness and color balance tend to occur, and a high-quality full-color image is stabilized. It is not easy to output.

When the shape factor SF-1 of the toner particles exceeds 150, the toner particles are separated from the spherical shape and approach an irregular shape, and the transfer efficiency of the toner image at the time of transfer from the electrostatic image carrier to the transfer material or the intermediate transfer medium is lowered. In addition, the transfer efficiency of the toner image during transfer from the intermediate transfer member to the transfer material is also reduced. The shape factor SF-1 of the toner particles is preferably 10 in order to improve the transfer efficiency of the toner image.
0 to 140, more preferably 100 to 130 is good.
Further, when the shape factor SF-2 of the toner particles exceeds 140, the surface of the toner particles is not smooth and the toner particles have a large number of irregularities, so that the electrostatic image carrier transfers to the transfer material or the intermediate transfer body. The transfer efficiency tends to decrease at the time of transfer and at the time of transfer from the intermediate transfer member to the transfer material.

In order to enhance the transfer efficiency of toner,
SF-2 is preferably 100 to 140, more preferably 100 to 130, and further preferably 100 to 125.
Is good. In order to improve the transfer efficiency of the toner image, it is preferable that the toner particles have a high sphericity and the degree of unevenness on the surface of the toner particles is low as described above.
-1 is 100 to 125 (more preferably 100 to 11
0) and SF-2 is 100 to 130 (more preferably 100 to 125).

The transfer efficiency is measured, for example, as follows.

The transfer rate of the toner image from the electrostatic image holding member to the intermediate transfer member is obtained by collecting the toner image (image density of about 1.5) formed on the electrostatic image holding member with a transparent adhesive tape, The image density is measured by a Macbeth densitometer or a color reflection densitometer (for example, Color reflection densitometer).
ether X-RITE 404A manufact
ured by X-Rite Co. ).
Next, the toner image is formed again on the electrostatic image holding member, the toner image is transferred to the intermediate transfer member, and the toner image on the intermediate transfer member corresponding to the toner image collected on the electrostatic image holding member is made transparent. Collect with an adhesive tape and measure the image density in the same manner.

Transfer rate A from electrostatic image carrier to intermediate transfer medium
(%) Is calculated as follows.

[0054]

(Equation 3)

Next, the transfer rate B from the intermediate transfer member to the transfer material
(%) Is similarly calculated as follows.

[0056]

[Equation 4]

The total transfer rate C is calculated as follows.

Overall transfer rate C = (transfer rate A) × (transfer rate B)

In the method of producing a toner using the pulverization method, it is difficult to set the toner shape factor SF-1 measured by Luzex within the range of 100 to 150, and in the melt spray method, SF- Even if one value can be set within a predetermined range, the particle size distribution of the obtained toner tends to be wide. On the other hand, in the dispersion polymerization method, the obtained toner shows an extremely sharp particle size distribution, but the selection of materials to be used is narrow and the use of organic solvents is not suitable for production equipment from the viewpoint of waste solvent treatment and solvent flammability. It is complicated and easily complicated. The emulsion polymerization method typified by soap-free polymerization is effective because the particle size distribution of the toner is relatively uniform, but when the emulsifier or polymerization initiator end used is present on the surface of the toner particle, the environmental characteristics are likely to be deteriorated.

In the present invention, the toner shape factor SF-
The suspension polymerization method under normal pressure or under pressure is particularly preferable because it can control the value of 1 to 100 to 150 and relatively easily obtain a fine particle toner having a particle size distribution of 4 to 8 μm with a sharp particle size distribution. Furthermore, a seed polymerization method in which a monomer is further adsorbed on the obtained polymer particles and then the resultant is polymerized using a polymerization initiator can also be suitably used in the present invention.

A more preferable toner used in the present invention is the toner shape factor SF-1 measured by Luzex.
Is 100 to 150 (more preferably 100 to 140,
More preferably 100 to 130), and 5 to 40 parts by weight of a release agent to 100 parts by weight of the binder resin,
Furthermore, the release agent has a core-shell structure in which the release agent is encapsulated by an outer shell resin layer (that is, a binder resin) by a method of measuring a tomographic plane of toner particles using a transmission electron microscope (TEM). Such toners can be produced directly by the suspension polymerization method.

When a large amount of a releasing agent is contained in the toner particles from the viewpoint of fixing property, it is inevitable that the releasing agent must be encapsulated by the outer shell resin. If it is not encapsulated, toner particles cannot be sufficiently pulverized unless special freeze pulverization is used in the pulverization process, and as a result only particles with a wide particle size distribution can be obtained, and toner fusion to the device also occurs. However, it is not preferable. In freeze-grinding, the apparatus becomes complicated due to measures for preventing condensation on the apparatus, and if the toner particles absorb moisture, it is necessary to add a drying step for the toner particles, which is a problem. As a specific method of encapsulating the release agent, the polarity of the material in the aqueous medium is set to be smaller for the release agent than for the main monomer, and a small amount of resin or monomer having a large polarity is added. By virtue of this, toner particles having a core-shell structure in which a release agent is coated with an outer shell resin can be obtained. To control the particle size distribution and particle size of toner particles, a method of changing the kind and addition amount of a sparingly water-soluble inorganic salt or a dispersant that acts as a protective colloid and mechanical device conditions (for example, the peripheral speed of the rotor, the number of passes, Predetermined toner particles can be obtained by controlling the stirring conditions such as the stirring blade shape and the container shape) or the solid content concentration in the aqueous solution.

As a specific method for measuring the tomographic plane of the toner, a cured product obtained by sufficiently dispersing the toner particles in an epoxy resin which is curable at room temperature and curing the toner for 2 days in an atmosphere at a temperature of 40 ° C. is used. After ruthenium trioxide and, if necessary, osmium tetroxide are used together for dyeing, a flaky sample is cut out using a microtome equipped with diamond teeth and the tomographic morphology of the toner is measured using a transmission electron microscope (TEM). In the present invention, it is preferable to use the ruthenium tetroxide dyeing method in order to make a contrast between materials by utilizing a slight difference in crystallinity between the release agent used and the resin constituting the outer shell. A typical example is shown in FIG.
It was observed that in the toner particles obtained in the examples described later, the release agent was encapsulated by the outer shell resin.

In the present invention, it is particularly preferable to further add a polar resin to the monomer composition in order to encapsulate the release agent in the toner particles. As the polar resin, a copolymer of styrene and (meth) acrylic acid, a maleic acid copolymer, an unsaturated polyester resin, a saturated polyester resin or an epoxy resin is preferably used. It is particularly preferable that the polar resin does not contain an unsaturated group capable of reacting with the shell resin or the vinyl monomer in the molecule. When a polar resin having an unsaturated group is contained, a cross-linking reaction occurs with the vinyl-based monomer forming the outer shell resin layer, resulting in an extremely high molecular weight as a full-color toner, which is disadvantageous for mixing four-color toner. Is not preferable.

When the direct polymerization method is used as the method for producing the toner particles, the polymerization initiator is, for example, 2,2 ′.
-Azobis- (2,4-dimethylvaleronitrile),
2,2'-azobisisobutyronitrile, 1,1'-azobis (cyclohexane-1-carbonitrile), 2,
Azo-based or diazo-based polymerization initiators such as 2'-azobis-4-methoxy-2,4-dimethylvaleronitrile and azobisisobutyronitrile; benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxy carbonate, cumene hydroperoxide, 2, Four
-Peroxide type polymerization initiators such as dichlorobenzoyl peroxide and lauroyl peroxide are used. The amount of the polymerization initiator used varies depending on the desired degree of polymerization, but is generally 0.5 to 20% by weight based on the polymerizable monomer. Although the type of the polymerization initiator varies slightly depending on the polymerization method, it may be used alone or in combination with reference to the 10-hour half-life temperature.

To control the degree of polymerization, known crosslinking agents, chain transfer agents, polymerization inhibitors and the like may be further added and used.

When the suspension polymerization method using a dispersion stabilizer is used as a method for producing toner particles, the dispersion stabilizer used is, as an inorganic compound, tricalcium phosphate, magnesium phosphate, aluminum phosphate, zinc phosphate. , Calcium carbonate, magnesium carbonate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, calcium metasilicate, calcium sulfate, barium sulfate, bentonite, silica, alumina and the like. Examples of the organic compound include polyvinyl alcohol, gelatin, methyl cellulose, methyl hydroxypropyl cellulose, ethyl cellulose, sodium salt of carboxymethyl cellulose, polyacrylic acid and its salt, starch and the like. These can be used by dispersing them in an aqueous phase. These dispersion stabilizers are added in an amount of 0.2 to 100 parts by weight of the polymerizable monomer.
It is preferred to use 20 parts by weight.

When an inorganic compound is used as the dispersion stabilizer, a commercially available product may be used as it is, but fine particles of the inorganic compound may be produced in a dispersion medium in order to obtain fine particles. For example, in the case of tricalcium phosphate,
It is advisable to mix the aqueous sodium phosphate solution and the aqueous calcium chloride solution under high-speed stirring.

For fine dispersion of these dispersion stabilizers,
You may use together 0.001-0.1 weight part surfactant. This is for accelerating the desired action of the dispersion stabilizer, and for example, sodium dodecylbenzenesulfate, sodium tetradecylsulfate, sodium pentadecylsulfate, sodium octylsulfate, sodium oleate, sodium laurate, potassium stearate. ，
Examples thereof include calcium oleate.

When the direct polymerization method is used as the method for producing the toner particles used in the present invention, the following production method is possible.

A releasing agent, a colorant, a charge control agent, a polymerization initiator and other additives made of a low softening point substance are added to the polymerizable monomer, and the mixture is uniformly dissolved by a homogenizer, an ultrasonic disperser or the like. The dispersed monomer composition is added to a conventional stirrer or homomixer in an aqueous phase containing a dispersion stabilizer,
Disperse with a homogenizer. Preferably, the stirring speed and stirring time are adjusted so that the droplets of the monomer composition have the desired toner particle size, and granulation is performed. After that, stirring may be performed to the extent that the particle state is maintained and the particles are prevented from settling due to the action of the dispersion stabilizer. The polymerization temperature is preferably set to 40 ° C. or higher, generally 50 to 90 ° C. for polymerization. The temperature may be raised during the latter half of the polymerization reaction, and for the purpose of improving durability in the image forming method of the present invention, the second half of the reaction for removing unreacted polymerizable monomers, by-products, or the like, or After completion of the reaction, a part of the aqueous medium may be distilled off from the reaction system. After the reaction is completed, the produced toner particles are collected by washing and filtration and dried. In the suspension polymerization method, it is usually preferable to use 300 to 3000 parts by weight of water as a dispersion medium with respect to 100 parts by weight of the monomer composition.

When the toner particles are produced by the melt-kneading-grinding-classification method, the shape factors SF-1 and SF-2 of the toner particles are set to 100 by heat and / or mechanical impact.
It is preferable to approach

Solubility parameter value (SP
The value) is preferably in the range of 7.5 to 9.7.
A release agent having an SP value of less than 7.5 has poor compatibility with the binder resin used, and as a result it is difficult to obtain a good dispersion in the binder resin. Adhesion to the developing sleeve is likely to occur, and the charge amount of toner is likely to change. Further, background fogging and density fluctuation during toner supply are also likely to occur. When a release agent having an SP value of more than 9.7 is used, when the toner is stored for a long time,
Blocking between toner particles easily occurs. Further, since the compatibility with the binder resin is too good, it is difficult to form a sufficient release layer between the fixing member and the toner fixed image at the time of fixing, and the offset phenomenon is likely to occur.

The SP value is determined by the method of Fedors [Polym. En
g. Sci. , 14 (2) 147 (1974)].

The melt viscosity of the release agent is VP manufactured by HAAKE.
In the method of measuring at -500 with a cone plate type rotor (PK-1) at -500, the melt viscosity at 130 ° C is preferably 1 to 300 cPs, and more preferably 3 to 50 cPs. Is particularly preferable. When the melt viscosity is lower than 1 cPs, the sleeve is liable to be contaminated by mechanical shearing force when the toner layer is thinly coated on the sleeve with a blade or the like in the one-component developing method. Even in the two-component developing method, when a toner is developed using a carrier, damage is likely to occur due to a shearing force between the toner and the carrier, so that an external additive is buried and toner particles are crushed. 300c
When the melt viscosity is higher than Ps, the viscosity of the monomer composition is too high when the toner particles are manufactured by using the polymerization method, and it is easy to obtain fine particle toner particles having a uniform particle diameter. However, the toner particles tend to have a wide particle size distribution.

The releasing agent preferably has a hardness of 0.3 to 5.0, more preferably Vickers hardness of 0.5 to 3.0.
Is particularly effective.

The hardness of the release agent can be measured by, for example, a measuring method using a Shimadzu dynamic ultra-micro hardness meter (DUH-200). The measurement condition is 0.5 using a Vickers indenter.
The Vickers hardness is obtained by displacing 10 μm at a load rate of 9.67 mg / sec under a g load and holding for 15 sec to analyze the dents on the sample. As a sample, a mold having a diameter of 20 mmφ is used, and a previously melted sample is molded into a cylindrical shape having a thickness of 5 mm and used.

Toner particles containing a release agent having a Vickers hardness of less than 0.3 are easily crushed at the cleaning portion of the copying machine in copying a large number of sheets, and toner fusion is likely to occur on the surface of the photosensitive drum. Black streaks are likely to occur. Furthermore, when multiple image samples are stored in layers,
A fixed toner image is likely to be formed on the back surface, which is not preferable. Toner particles containing a release agent having a Vickers hardness of more than 5.0 require unnecessarily high pressure in the fixing device used for heat fixing, which is not preferable.

Next, the hydrophobized inorganic fine powder having an average particle diameter of 10 to 90 nm and having a function as a fluidity improving agent for toner particles will be described.

As the matrix of the hydrophobized inorganic fine powder,
Metal acid compounds such as titanium oxide, aluminum oxide, strontium titanate, cerium oxide and magnesium oxide; nitrides such as silicon nitride; carbides such as silicon carbide; metal salts such as calcium sulfate, barium sulfate and calcium carbonate; carbon fluoride And so on. Of these, titanium oxide is more preferable, and a method for producing the titanium oxide includes a method of vapor-phase oxidizing a titanium halogen compound or a titanium alkoxide. Titanium oxide may be either crystalline (anatase type, rutile type) or amorphous.

As a method for hydrophobizing the inorganic fine powder, either a wet method or a dry method may be used.

Examples of the hydrophobizing agent include silane coupling agents, titanium coupling agents, aluminate coupling agents, zircoaluminum coupling agents and silicone oils. Particularly preferably used is a silane coupling agent having the general formula R _m SiY _n [wherein, R represents an alkoxy group, Y represents an alkyl group,
A hydrocarbon group such as a vinyl group, a glycidoxy group, and a methacryl group is shown, m is an integer of 1 to 3, and n is an integer of 1 to 3. ] The thing represented by the integer of n: 1-3 is mentioned. Among the silane coupling agents, monoalkyltrialkoxysilane coupling agents are particularly preferable.

Specific examples of the silane coupling agent include:
Vinyltrimethoxysilane, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane, methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, propyltrimethoxysilane, propyl Triethoxysilane, butyltrimethoxysilane, butyltriethoxysilane, isobutyltrimethoxysilane, isobutyltriethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, trimethylmethoxysilane, hydroxypropyltrimethoxysilane, phenyltrimethoxysilane, n
-Hexadecyltrimethoxysilane, n-octadecyltrimethoxysilane, n-butyltrimethoxysilane,
Examples thereof include n-octyltrimethoxysilane.

The treatment amount of the hydrophobizing agent is 1 to 50 parts by weight, more preferably 3 to 4 parts by weight, relative to 100 parts by weight of the inorganic fine powder.
0 parts by weight is preferred. If the treatment amount is less than 1 part by weight, the effect of hydrophobizing is small, and the leakage of charge is fast under high humidity.
The charge stability of the toner decreases. When the treatment amount exceeds 50 parts by weight, the hydrophobicity becomes too high and the charge amount of the toner tends to become excessive under low humidity. In addition, it also promotes the generation of coarse secondary particles, and the effect of improving fluidity is likely to decrease.

The average particle size of the hydrophobized inorganic fine powder was 50,000 times that of the inorganic fine powder taken by a scanning electron microscope (manufactured by Hitachi, Ltd.), and the particle size was 5 nm by LUZEX III (manufactured by Nireco). The diameter of the above 100 or more particles is measured, and the average value is obtained.

The hydrophobized inorganic fine powder has a hydrophobization degree of 2
0 to 80% (more preferably 35 to 80%) is preferable. The degree of hydrophobicity was measured by adding 0.2 g of the fine powder to be tested to water in an Erlenmeyer flask.
Add to 0 ml and titrate methanol from burette until the total amount of fine powder is wet. At this time, the solution in the flask is constantly stirred with a magnetic stirrer. The end point is observed by suspending the total amount of fine powder in the liquid and the degree of hydrophobization is expressed as the percentage of methanol in the liquid mixture of methanol and water when the end point is reached.

When the hydrophobicity is less than 20%, the charge amount of the toner is apt to decrease due to long-term standing under high humidity.
If the degree of hydrophobicity exceeds 80%, it becomes difficult to control the charge of the fine powder itself, and as a result, the toner is likely to be charged up under low humidity.

The hydrophobized inorganic fine powder had an absolute value of triboelectric charge amount of 45 mC / kg measured using an iron powder carrier.
The following (more preferably 30 mC / kg or less) is preferable from the viewpoint of stability of the charge amount of the small particle size toner.

The triboelectric charge amount of the hydrophobized inorganic fine powder is
2 parts by weight of hydrophobized inorganic fine powder and iron powder carrier (for example, iron powder carrier EFV-2 manufactured by Powder Tech Co., Ltd.)
(00/300) 98 parts by weight in a polyethylene container and shaken 300 to 400 times, and then measured in the same manner as the measurement of the triboelectric charge amount of the toner described below.

Further, the hydrophobized inorganic fine powder has a BET specific surface area of 100 to 300 measured using nitrogen gas.
Having m ² / g is preferable in order to efficiently improve the fluidity of the toner particles.

In the present invention, the hydrophobized inorganic fine powder is preferably used in an amount of 0.05 to 3.5 parts by weight, more preferably 0.1 to 2.0 parts by weight, based on 100 parts by weight of the toner particles. If the addition amount is less than 0.05 parts by weight,
The fluidity imparting property to the toner particles is lowered. If the addition amount exceeds 3.5 parts by weight, the particles liberated from the toner particles are likely to contaminate the surface of the carrier and the developing sleeve, and as a result, the charge amount of the toner is likely to decrease.

Next, the hydrophobized silicon compound fine powder used for preventing or suppressing the above-mentioned hydrophobized inorganic fine powder from being buried in the surface of the toner particles will be described.

As the matrix of the hydrophobized silicon compound fine powder, silica fine powder or silicone resin fine powder is preferable. As the silica fine powder, it is possible to use a fine powder having an inorganic fine particle other than silica as a core and a surface made of silica.

Examples of the method for producing fine silica powder include vapor phase oxidation of a silicon halogen compound and a sol-gel method.

For hydrophobizing the silicon compound, a silane coupling agent and silicone oil are preferable as the hydrophobizing agent. As the silane coupling agent, hexamethyldisilazane, trimethylsilane, trimethylchlorosilane, trimethylethoxysilane, dimethyldichlorosilane, methyltrichlorosilane, allyldimethylchlorosilane, allylphenyldichlorosilane, benzyldimethylchlorosilane, bromomethyl Dimethylchlorosilane,
α-chloroethyltrichlorosilane, β-chloroethyltrichlorosilane, chloromethyldimethylchlorosilane, triorganosilylacrylate, vinyldimethylacetoxysilane, dimethylethoxysilane, dimethyldimethoxysilane, diphenyldiethoxysilane, hexamethyldisiloxane, 1, Examples thereof include 3-divinyltetramethyldisiloxane and 1,3-diphenyltetramethyldisiloxane.

A nitrogen-containing silane coupling agent may be used in order to impart positive triboelectric charging characteristics to the hydrophobized silicon compound fine powder. As the nitrogen-containing silane coupling agent, aminopropyltrimethoxysilane, aminopropyltriethoxysilane, dimethylaminopropyltrimethoxysilane, diethylaminopropyltrimethoxysilane, dipropylaminopropyltrimethoxysilane, dibutylaminopropyltrimethoxysilane,
Monobutylaminopropyltrimethoxysilane, dioctylaminopropyltrimethoxysilane, dibutylaminopropyldimethoxysilane, dibutylaminopropylmonomethoxysilane, dimethylaminophenyltriethoxysilane, trimethoxysilyl-γ-propylphenylamine, trimethoxysilyl-γ -Propylbenzylamine and the like.

Examples of the silicone oil include those represented by the following formula.

[0098]

Embedded image

[In the formula, R represents a C _1-3 alkyl group,
R'represents a silicone oil modifying group such as alkyl, halogen modified alkyl, phenyl, modified phenyl, R "
Represents a C _1-3 alkyl group or an alkoxy group. ]

Examples thereof include dimethyl silicone oil, alkyl modified silicone oil, α-methylstyrene modified silicone oil, chlorophenyl silicone oil, and fluorine modified silicone oil. The silicone oil preferably has a viscosity at 25 ° C. of 50 to 100 centistokes.

A nitrogen-containing silicone oil may be used for imparting hydrophobicity and positive triboelectric charging properties to the hydrophobized silicon compound fine powder.

As the silicone oil having a nitrogen atom in the side chain, a silicone oil having at least a partial structure represented by the following formula can be used.

[0103]

Embedded image

(Wherein R ₁ represents hydrogen, an alkyl group, an aryl group or an alkoxy group, R ₂ represents an alkylene group or a phenylene group, and R ₃ and R ₄ represent hydrogen, an alkyl group or an aryl group. , R ₅ represents a nitrogen-containing heterocyclic group.)

The alkyl group, aryl group, alkylene group and phenylene group may have an organo group having a nitrogen atom, and may have a substituent such as halogen within a range not impairing the charging property. It may be.

The amount of the hydrophobizing agent used in the hydrophobizing treatment is 1 part with respect to 100 parts by weight of the silicon compound fine powder.
˜50 parts by weight, more preferably 2-35 parts by weight. Hydrophobicity is 30 to 80%, more preferably 35 to 7
5% is preferable.

The hydrophobized silicon compound fine powder is
The particle size distribution is larger than that of silica fine powder which is usually used for preventing or suppressing the hydrophobic inorganic fine powder used for remarkably improving the fluidity of toner particles from being embedded in the surface of the toner particles. Widely used and containing coarse particles. As an example of the hydrophobized silicon compound fine powder used in the present invention, particle size distributions of hydrophobic silica fine powders (A) and (B) containing coarse particles are shown in FIGS. 1 and 2. On the other hand, a particle size of 3 which is usually used as a fluidity improver
3 and 4 show the particle size distribution of the hydrophobic silica fine powders (C) and (D) having a small average particle size and containing almost no particles of 0 nm or more.

The hydrophobized silicon compound fine powder used in the present invention has an average particle size of 30 to 120 nm, has a wide particle size distribution, and contains 15 to 45% by number of silicon compound particles having a particle size of 5 to 30 nm ( Preferably, it is 20 to 40% by number) and contains 30 to 60 silicon compound particles having a particle diameter of 30 to 60 nm.
70% by number (preferably 45 to 70% by number, more preferably 50 to 70% by number), and 5 to 45% by number (preferably 10 to 10) of silicon compound particles having a particle diameter of 60 nm or more.
40% by number).

The amount of the hydrophobized silicon compound used in the present invention is 0.05 based on 100 parts by weight of the toner particles.
˜3.5 parts by weight, more preferably 0.1 to 2.0 parts by weight.

The hydrophobic silica fine powder (A) shown in FIG.
The average particle size is 40 nm, the BET specific surface area measured using nitrogen gas is 60 m ² / g, and the hydrophobicity is 68.
%, The triboelectric charge amount is −170 mC / kg, contains 28% by number of silica particles having a particle size of 5 to 30 nm, and contains 60.5% by number of silica particles having a particle size of 30 to 60 nm,
It contains 11.5% by number of silica particles having a particle diameter of 60 nm or more.

The hydrophobic silica fine powder (B) shown in FIG.
The average particle size is 53 nm and the BET specific surface area is 50 m ^2.
/ G, the degree of hydrophobicity is 65%, and the triboelectric charge amount is-.
160 mC / kg, containing 19% by number of silica particles having a particle size of 5 to 30 nm, 42% by number of silica particles having a particle size of 30 to 60 nm, and 39% by number of silica particles having a particle size of 60 nm or more. There is.

The hydrophobized silicon compound fine powders such as the hydrophobic silica fine powders (A) and (B) satisfactorily prevent the fluidity-improving agent from being embedded in the toner particle surface, and further, the transfer step. It is possible to increase the transfer rate of the toner image in the above step, and satisfactorily remove the residual small-sized toner particles from the electrostatic image holding member in the cleaning step. The above effect is presumed to be because the silicon compound fine powder contains coarse particles having a large particle size, the coarse particles are hard to be buried in the toner particle surface, and the coarse particles function as a spacer. Furthermore, when using a hydrophobized silicon compound fine powder having a larger triboelectric charge absolute value than the fluidity improver, it is more closely adhered to the toner particles than the fluidity improver and It is possible to prevent the embedding of the improver on the surface of the toner particles even better.

On the other hand, the hydrophobic silica fine powder (C) shown in FIG. 3 has an average particle size of 16 nm, a BET specific surface area of 130 m ² / g, and a hydrophobicity of 28%.
Triboelectric charge amount is -200 mC / kg, particle size is 5 to 30
100% of silica particles of nm are contained.

Further, the hydrophobic silica fine powder (D) shown in FIG. 4 has an average particle diameter of 12 nm, a BET specific surface area of 200 m ² / g, a hydrophobicity of 23%, and a triboelectric charge amount. Is -210 mC / kg, and the particle size is 5 to 30 n
100% by number of m silica particles are contained.

The hydrophobic silica fine powders (C) and (D) are
The particle size distribution is sharp and does not contain coarse particles,
Although used as a fluidity improver, the effect of preventing the inorganic fine powder hydrophobized from being embedded in the toner particles even when the hydrophobic silica fine powders (C) and (D) are added to the toner particles Are extremely few.

The hydrophobized silicon compound fine powder was measured by using nitrogen gas in order to better prevent the hydrophobized inorganic fine powder functioning as a fluidity improver from being embedded in the toner particle surface. The BET specific surface area is 80 m ² / g or less (more preferably 70 m ² / g or less), and the absolute value of the triboelectric charge amount with respect to the iron powder carrier is 50 to 300 m.
C / kg (more preferably 70 to 250 mC / kg)
Is good.

The effect of the combined use of the hydrophobized inorganic fine powder and the hydrophobized silicon compound fine powder in the present invention is that the shape factors SF-1 and SF-2 of the toner particles are 100.
The closer to, the more pronounced.

The toner of the present invention can be usually used for one-component and two-component developers. As a one-component developer,
In the case of a magnetic toner in which a magnetic material is contained in toner particles, there is a method of using a magnet built in a developing sleeve to convey and charge the magnetic toner. When a non-magnetic toner containing no magnetic substance is used, there is a method in which a blade or a roller is used, and the toner is forcibly charged by friction with a developing sleeve so that the toner adheres to the sleeve for conveyance.

When used as a two-component type developer, a carrier is used together with the toner of the present invention and the developer is used. The magnetic carrier is composed of an element consisting of iron, copper, zinc, nickel, cobalt, manganese, and chromium elements alone or in a composite ferrite state. The shape of the magnetic carrier may be spherical, flat or amorphous. Furthermore, the fine structure of the surface state of the magnetic carrier particles (for example, surface irregularity)
Is also preferably controlled. Generally, a method is used in which the above-mentioned inorganic oxide is fired and granulated to generate magnetic carrier core particles in advance and then coated on a resin. From the viewpoint of reducing the load on the toner of the magnetic carrier, after kneading the inorganic oxide and the resin, pulverizing and classifying to obtain a low-density dispersed carrier, and further, directly kneading the inorganic oxide and the monomer It is also possible to use a method of obtaining a spherical spherical magnetic carrier by suspension polymerization in an aqueous medium.

A coated carrier in which the surface of the carrier particles is coated with a resin is particularly preferable. As the method, a method in which a resin is dissolved or suspended in a solvent and applied and then attached to a carrier, or a method in which a resin powder and carrier particles are simply mixed and attached can be applied.

The substance adhered to the surface of the carrier particles varies depending on the toner material, and examples thereof include polytetrafluoroethylene, monochlorotrifluoroethylene polymer, polyvinylidene fluoride, silicone resin, polyester resin, styrene resin, acrylic resin and polyacid. , Polyvinyl butyral, amino acrylate resin and the like. These are used alone or in plural.

The magnetic properties of the carrier are preferably as follows.
The strength of magnetization (σ ₁₀₀₀ ) at 1000 Oersted after magnetically saturating is 30 to 300 emu / cm ³
It is necessary to be. In order to achieve higher image quality, it is preferably 100 to 250 emu / cm ³ . If it is higher than 300 emu / cm ^3, it becomes difficult to obtain a high-quality toner image. 30 em
When it is less than u / cm ³ , carrier adhesion is likely to occur because the magnetic restraining force also decreases.

The carrier shape is SF1 indicating the degree of roundness.
Is 180 or less, and SF2 indicating the degree of unevenness is preferably 250 or less. In addition, SF-1 and SF-2 are defined by the following formulas, and LVZEX III manufactured by Nireco Co., Ltd.
Is measured at.

[0124]

(Equation 5)

When a two-component developer is prepared by mixing the toner of the present invention and a magnetic carrier, the mixing ratio is 2% by weight to 15% by weight, preferably 4% by weight to the toner concentration in the developer. 13% by weight usually gives good results.

An image forming method to which the toner of the present invention is applicable will be described below with reference to the accompanying drawings.

The toner of the present invention can be mixed with a magnetic carrier and developed by using a developing means as shown in FIG. 5, for example. Specifically, it is preferable to perform development in a state where the magnetic brush is in contact with the electrostatic image carrier (for example, the photoconductor drum) 3 while applying an alternating electric field. Distance between developer bearing member (developing sleeve) 1 and photosensitive drum 3 (S-
The distance D) B is preferably 100 to 1000 μm for preventing carrier adhesion and improving dot reproducibility. If it is narrower than 100 μm, the supply of the developer tends to be insufficient and the image density becomes low, and if it exceeds 1000 μm, the magnetic lines of force from the magnet S1 spread and the density of the magnetic brush becomes low, resulting in poor dot reproducibility and restraining the carrier. The force to do so weakens and carrier adhesion easily occurs.

The voltage between the peaks of the alternating electric field is 500 to 50.
00V is preferable, the frequency is 500 to 10000 Hz,
The frequency is preferably 500 to 3000 Hz, and can be appropriately selected and used for each process. In this case, the waveform may be triangular wave, rectangular wave, sine wave, or duty.
Various waveforms with different ratios can be selected and used. If the applied voltage is lower than 500 V, it may be difficult to obtain a sufficient image density, and the fog toner in the non-image area may not be collected well. If it exceeds 50,000 V, the electrostatic image may be disturbed via the magnetic brush, which may lead to deterioration in image quality.

By using a two-component type developer having a well-charged toner, the fogging removal voltage (Vback)
Can be lowered, and the primary charging of the photoconductor can be reduced, so that the life of the photoconductor can be extended. Vbac
The value k depends on the developing system, but is preferably 150 V or less, more preferably 100 V or less.

The contrast potential is preferably 200 V to 500 V so that a sufficient image density can be obtained.

When the frequency is lower than 500 Hz, although it is related to the process speed, charge injection into carriers may occur, which may deteriorate the image quality by adhering carriers or disturbing the latent image. If it exceeds 10000 Hz, the toner cannot follow the electric field and the image quality is likely to deteriorate.

The contact width (developing nip C) of the magnetic brush on the developing sleeve 1 with the photosensitive drum 3 is preferably in order to obtain sufficient image density, excellent dot reproducibility, and development without carrier adhesion. It is to be 3 to 8 mm. If the developing nip C is narrower than 3 mm, it is difficult to satisfactorily satisfy sufficient image density and dot reproducibility.
If it is wider than m, the packing of the developer may occur and the operation of the machine may be stopped, or it may be difficult to sufficiently suppress the carrier adhesion. As a method of adjusting the developing nip, the nip width is appropriately adjusted by adjusting the distance A between the developer regulating member 2 and the developing sleeve 1 or the distance B between the developing sleeve 1 and the photosensitive drum 3.

Particularly in outputting a full-color image in which halftone is emphasized, three or more developing units for magenta, cyan, and yellow are used, and the developer and the developing method of the present invention are used. By combining with a developing system that forms a latent image, there is no influence of the magnetic brush and the latent image is not disturbed, so that it is possible to develop the dot latent image faithfully. Even in the transfer step, a high transfer rate can be achieved by using the toner of the present invention, and therefore high image quality can be achieved in both the halftone portion and the solid portion.

Further, by using the toner of the present invention together with the improvement of the initial image quality, the effects of the present invention can be sufficiently exhibited even when copying a large number of sheets without the image quality deterioration.

The toner image on the electrostatic image carrier 3 is transferred onto a transfer material by a transfer means 23 such as a corona charger, and the toner image on the transfer material is heated by a heating roller 26 and a pressure roller 25. It is fixed by pressure fixing means. The transfer residual toner on the electrostatic image holding member 3 is removed from the electrostatic image holding member 3 by a cleaning unit such as a cleaning blade. The toner of the present invention has a high transfer efficiency in the transfer step, a small amount of transfer residual toner, and excellent cleaning property, and therefore filming is less likely to occur on the electrostatic image holding member. Further, even when a multi-sheet durability test is performed, the toner of the present invention has less burial of the external additive on the surface of the toner particles than the conventional toner, so that good image quality can be maintained for a long time.

In order to obtain a good full-color image, it is preferable to have a developing device for magenta, cyan, yellow, and black, and to give a tight image by the last development of black. it can.

An example of an image forming apparatus capable of favorably carrying out the full-color image forming method will be described with reference to FIG.

The color electrophotographic apparatus shown in FIG. 6 includes a transfer material conveying system 1 provided from the right side of the apparatus main body to the substantially central portion of the apparatus main body, and the transfer material conveying system at the substantially central portion of the apparatus main body. A latent image forming portion II provided in the vicinity of the transfer drum 315 constituting I, and a developing means (that is, a rotary developing device) III arranged in the vicinity of the latent image forming portion II. It is roughly divided into.

The transfer material carrying system I has the following structure. An opening is formed in the right wall (right side in FIG. 6) of the apparatus body, and transfer material supply trays 302 and 303 that are detachable are provided in the opening so as to partially project outside the machine. Paper feed rollers 304 and 305 are disposed substantially directly above the trays 302 and 303, and these paper feed rollers 304 and 305 and a transfer drum 305 disposed on the left side and rotatable in the direction of arrow A are arranged. A paper feed roller 306 and paper feed guides 307 and 308 are provided so as to be linked. In the vicinity of the outer peripheral surface of the transfer drum 315, the contact rollers 309 are arranged from the upstream side to the upstream side in the rotation direction.
Gripper 310, transfer material separation charger 311, separation claw 3
12 are sequentially arranged.

A transfer charger 313 and a transfer material separating charger 314 are provided on the inner peripheral side of the transfer drum 315. A transfer sheet (not shown) made of a polymer such as polyvinylidene fluoride is attached to a portion of the transfer drum 315 around which the transfer material is wound, and the transfer material is electrostatically attached on the transfer sheet. It is attached closely to. A conveyor belt means 316 is provided on the upper right side of the transfer drum 315 in proximity to the separation claw 312, and a fixing device 318 is provided at the end (right side) of the conveyor belt means 316 in the transfer material conveying direction. There is. A discharge tray 317 that extends to the outside of the apparatus main body 301 and is detachable from the apparatus main body 301 is disposed further downstream than the fixing device 318 in the transport direction.

Next, the structure of the latent image forming section II will be described. A photosensitive drum (for example, an OPC photosensitive drum) 319 that is a latent image bearing member that is rotatable in the direction of the arrow in FIG. 6 is arranged with its outer peripheral surface in contact with the outer peripheral surface of the transfer drum 315. Above the photosensitive drum 319 and in the vicinity of the outer peripheral surface thereof, a charge removing charger 320 and a cleaning unit 321 are provided from the upstream side to the downstream side in the rotation direction of the photosensitive drum 319.
And a primary charger 323 are sequentially arranged, and an image exposure unit 324 such as a laser beam scanner for forming an electrostatic latent image on the outer peripheral surface of the photosensitive drum 319 and an image exposure reflection unit 325 such as a mirror. It is arranged.

The structure of the rotary developing device III is as follows. A rotatable housing (hereinafter referred to as “rotating body”) 3 is provided at a position facing the outer peripheral surface of the photosensitive drum 319.
26, four types of developing devices are mounted at four positions in the circumferential direction in the rotating body 326.
The electrostatic latent image formed on the outer peripheral surface of is visualized (that is, developed). The above four types of developing devices
Each has a yellow developing device 327Y, a magenta developing device 327M, a cyan developing device 327C, and a black developing device 327BK.

The sequence of the entire image forming apparatus having the above configuration will be described by taking the case of the full color mode as an example. When the photosensitive drum 319 described above rotates in the direction of the arrow in FIG.
Is charged by. In the apparatus of FIG. 6, the peripheral speed of the photosensitive drum 319 (hereinafter, referred to as process speed) is 1
00 mm / sec or more (for example, 130 to 250 mm /
sec). Photosensitive drum 3 by primary charger 323
19 is charged, image exposure is performed by the laser light E modulated by the yellow image signal of the original 328, an electrostatic latent image is formed on the photosensitive drum 319, and development is performed in advance by rotation of the rotating body 326. The electrostatic latent image is developed by the yellow developing device 327Y fixed at the position, and a yellow toner image is formed.

The transfer material conveyed through the paper feed guide 307, the paper feed roller 306, and the paper feed guide 308 is held by the gripper 310 at a predetermined timing, and is brought into contact with the contact roller 309 and the corresponding contact roller. It is electrostatically wound around the transfer drum 315 by the electrodes facing each other. The transfer drum 315 rotates in the direction of the arrow in FIG. 6 in synchronization with the photosensitive drum 319, and the yellow developing device 3
The yellow toner image formed by 27Y is transferred onto the transfer material by the transfer charger 313 at a portion where the outer peripheral surface of the photosensitive drum 319 and the outer peripheral surface of the transfer drum 315 are in contact with each other. The transfer drum 315 continues to rotate and is ready for the transfer of the next color (magenta in FIG. 6).

The photosensitive drum 319 is the above-mentioned charger 3 for static elimination.
After the charge is removed by 20 and the cleaning means 321 by the cleaning blade cleans it, it is charged again by the primary charger 323, and image exposure is performed by the next magenta image signal to form an electrostatic latent image. The rotary developing device rotates while an electrostatic latent image is formed on the photosensitive drum 319 by imagewise exposure with a magenta image signal to position the magenta developing device 327M at the above-described predetermined developing position and to perform a predetermined operation. Develop with magenta toner. Subsequently, the above-described process is performed for cyan and black, respectively, and when the transfer of the toner images of four colors is completed, the three-color visible image formed on the transfer material is charged by each of the chargers 322 and 314. The gripping of the transfer material by the gripper 310 is released, the transfer material is separated from the transfer drum 315 by the separating claw 312, and the transfer belt 316 fixes the fixing material to the fixing device 3.
Then, it is sent to 18 and fixed by heat and pressure to complete a series of full-color printing sequence, and a required full-color printing image is formed on one surface of the transfer material.

Next, another image forming method will be described more specifically with reference to FIG.

In the apparatus system shown in FIG. 7, the developing devices 74-1, 74-2, 74-3, and 74-4 respectively have a developer having a cyan toner, a developer having a magenta toner, and a developer having a yellow toner. A developer having a developing agent and black toner is introduced, and the electrostatic charge image formed on the photoconductor 71 is developed by a magnetic brush development system or a non-magnetic one-component development system, and each color toner image is formed on the photoconductor 71. It Photoreceptor 71 is a-Se, Cds, Zn
It is a photosensitive drum or photosensitive belt having a photoconductive insulating material layer such as O ₂ , OPC and a-Si. The photoconductor 71 is rotated in the arrow direction by a driving device (not shown).

As the photosensitive member 71, a photosensitive member having an amorphous silicon photosensitive layer or an organic photosensitive layer is preferably used.

As the organic photosensitive layer, the photosensitive layer contains a charge generating substance and a substance having a charge transporting property in the same layer.
It may be a single layer type or a function-separated type photosensitive layer in which the charge transport layer comprises a charge generation layer as a component. A laminated photosensitive layer having a structure in which a charge generation layer and then a charge transport layer are laminated in this order on a conductive substrate is one of preferred examples.

Polycarbonate resin, polyester resin, and acrylic resin are particularly preferable as the binder resin of the organic photosensitive layer because of good transferability and cleaning property, poor cleaning, fusing of toner to the photoreceptor, and filming of external additives. Hard to happen.

In the charging step, there are a method of non-contact with the photoreceptor 71 using a corona charger, and a contact type method using a roller or the like, any of which is used. A contact type as shown in FIG. 7 is preferably used for efficient uniform charging, simplification and low ozone generation.

The charging roller 72 has a core metal bar 72b at the center and a conductive elastic layer 72a forming the outer periphery thereof as a basic structure. The charging roller 72 is pressed against the surface of the photoconductor 71 with a pressing force, and is rotated by the rotation of the photoconductor 71.

A preferable process condition when the charging roller is used is that the contact pressure of the roller is 5 to 500 g / cm.
When an AC voltage superimposed on a DC voltage is used, AC voltage = 0.5 to 5 kVpp, AC frequency = 50
Hz to 5 kHz, DC voltage = ± 0.2 to ± 1.5 kV, and when DC voltage is used, DC voltage = ± 0.2 to
± 5 kV.

As another charging means, there are a method using a charging blade and a method using a conductive brush. These contact charging means are effective in that high voltage becomes unnecessary and ozone generation is reduced.

As the material of the charging roller and the charging blade as the contact charging means, conductive rubber is preferable, and a releasing film may be provided on the surface thereof. As the releasable coating, nylon resin, PVDF (polyvinylidene fluoride), PVDC (polyvinylidene chloride), etc. can be applied. The toner image on the photoconductor has a voltage (for example, ± 0.
1 to ± 5 kV) is transferred to the intermediate transfer member 5. After the transfer, the surface of the photoreceptor is cleaned by the cleaning blade 7.
It is cleaned by the cleaning means 79 having the number 8.

The intermediate transfer member 75 is composed of a pipe-shaped conductive core 75b and an elastic layer 75 of medium resistance formed on the outer peripheral surface thereof.
a. The cored bar 75b may be a plastic pipe coated with conductive plating.

The elastic layer 75a of medium resistance is made of silicone rubber, Teflon rubber, chloroprene rubber, urethane rubber,
EPDM (ethylene propylene diene terpolymer)
Conductivity-imparting materials such as carbon black, zinc oxide, tin oxide, and silicon carbide are mixed and dispersed in elastic materials such as to adjust the electric resistance value (volume resistivity) to a medium resistance of 10 ⁵ to 10 ¹¹ Ω · cm. A solid or foamed fleshy layer.

The intermediate transfer member 75 is disposed in parallel with the photosensitive member 71 so as to be in contact with the lower surface of the photosensitive member 71, and rotates in the counterclockwise direction indicated by an arrow at the same peripheral speed as the photosensitive member 71. To do.

The toner image of the first color formed and carried on the surface of the photoconductor 71 is transferred by the transfer bias applied to the intermediate transfer body 75 while passing through the transfer nip portion where the photoconductor 71 and the intermediate transfer body 75 are in contact with each other. The intermediate transfer is sequentially performed on the outer surface of the intermediate transfer body 75 by the electric field formed in the nip region.

If necessary, the removable cleaning means 80 cleans the surface of the intermediate transfer member 75 after the toner image is transferred onto the transfer material. When there is a toner image on the intermediate transfer body, the cleaning unit 80 is separated from the surface of the intermediate transfer body so as not to disturb the toner image.

A transfer means is disposed in parallel with the intermediate transfer body 75 so as to be in contact with the lower surface of the intermediate transfer body 75, and the transfer means 77 is, for example, a transfer roller or a transfer belt. Rotates clockwise at the same peripheral speed as the arrow. The transfer means 77 may be arranged so as to be in direct contact with the intermediate transfer body 75, or a belt or the like may be arranged so as to be in contact between the intermediate transfer body 75 and the transfer means 77.

In the case of the transfer roller, the core metal 77b at the center and the conductive elastic layer 77a forming the outer periphery of the metal core 77b are the basic components.

As the intermediate transfer member and the transfer roller, general materials can be used. By setting the volume resistivity of the elastic layer of the transfer roller smaller than the volume resistivity of the elastic layer of the intermediate transfer member, the voltage applied to the transfer roller can be reduced and a good toner image can be formed on the transfer material. In addition, it is possible to prevent the transfer material from being wound around the intermediate transfer body. Particularly, it is particularly preferable that the volume resistivity of the elastic layer of the intermediate transfer body is 10 times or more than the volume resistivity of the elastic layer of the transfer roller.

The hardness of the intermediate transfer member and the transfer roller is JI.
It is measured according to SK-6301. The intermediate transfer member used in the present invention is preferably composed of an elastic layer belonging to the range of 10 to 40 degrees, while the hardness of the elastic layer of the transfer roller is higher than that of the elastic layer of the intermediate transfer member.
Those having a value of -80 degrees are preferable in order to prevent the transfer material from winding around the intermediate transfer member. When the hardness of the intermediate transfer body and that of the transfer roller are opposite, a recess is formed on the transfer roller side, and the transfer material is likely to be wound around the intermediate transfer body.

The transfer means 77 is rotated at a constant speed or a peripheral speed different from that of the intermediate transfer body 75. The transfer material 6 is conveyed between the intermediate transfer body 5 and the transfer means 77, and at the same time, a bias having a polarity opposite to the frictional charge of the toner is applied to the transfer means 77 from the transfer bias means 75. Toner image is transferred to the surface side of the transfer material 76.

The same material as the charging roller can be used as the material of the transfer rotary member, and the contact pressure of the roller is 5 to 500 g / c as a preferable transfer process condition.
m, the DC voltage is ± 0.2 to ± 10 kV.

For example, the conductive elastic layer 77b of the transfer roller
Is a polyurethane in which a conductive material such as carbon is dispersed, an ethylene-propylene-diene terpolymer (EPDM)
It is made of an elastic body having a volume resistance of about 10 ⁶ to 10 ¹⁰ Ωcm. A bias is applied to the core metal 77a by a constant voltage power source. The bias condition is ± 0.2 to
± 10 kV is preferable.

Next, the transfer material 76 is conveyed to a fixing device 81 which is basically composed of a heating roller having a heating element such as a halogen heater built therein and an elastic pressure roller pressed against the heating roller by a pressing force, and heated. The toner image is heated and pressed and fixed on the transfer material by passing between the roller and the pressure roller. A method of fixing with a heater through a film may be used.

The evaluation methods of fixing property, offset resistance, blocking resistance, cleaning property, toner charge amount under three environments, image density change and image quality deterioration in Examples described later will be described below.

1) Fixing property and anti-offset property An unfixed image of toner is prepared by a commercially available copying machine.

When the toner is black toner, the fixing property and the offset resistance are evaluated by a heat roller external fixing device having no oil application mechanism.

Further, in the case of mono-color toner or full-color toner, a heat roller external fixing device without an oil application mechanism or a fixing device of Canon digital full-color copying machine CLC-500 is used to evenly disperse some oil. Apply to the fixing roller (eg 0.02g / A4 size)
Then, fixability and offset resistance are evaluated, and a fixed image for transparency evaluation is obtained.

At this time, as the roller material, one having a surface layer of fluorine resin or rubber is used for both the upper roller and the lower roller.

A heat roller external fixing machine having an upper roller and a lower roller having a roller diameter of about 60 mm is used, and fixing conditions are nip 6 when the transfer material is SK paper (manufactured by Nippon Paper Industries Co., Ltd.). The temperature is adjusted to 5 mm and the process speed is 105 mm / sec in the temperature range of 80 to 230 ° C. at every 5 ° C.

The transfer material is, for example, an OHP sheet (trade name CG
3300, manufactured by 3M), the nip 6.5 mm,
Process speed 25mm / sec, temperature 150 ℃
Fix with.

The fixing property is such that a fixed image (including a low-temperature offset image) is applied with a load of 50 g / cm ² on a sillbon paper [Lenz Cleaning Paper “das”].
per (R) "(Ozu Paper Co. Lt
Rubbing 10 times with d)], the temperature at which the density decrease rate before and after rubbing becomes less than 10% is the fixing start point.

The anti-offset property is that the temperature at which the offset disappears visually is taken as the low-temperature offset starting point, and the temperature is raised.
The highest temperature without offset is the high temperature offset end point.

2) Blocking resistance As for the blocking resistance, 5 g of the toner was sampled and placed in a 50 cc polyethylene cup, and then 40, 45, 50 ° C.
After standing for 2 days in a drying room kept at 1, the toner was visually checked to see if it aggregated. If they are not aggregated, they are represented by "○", and if they are aggregated, they are represented by "x".

3) Cleanability and image quality After externally adding an appropriate amount of an external additive to prepare a toner and then a developer, under an environment of 22 ° C./60% (hereinafter, normal temperature / normal humidity). ), A commercially available copying machine Canon full color copying machine CLC-500 is used to perform a 50,000-sheet durability test, and the cleaning property and the image quality are visually evaluated.

The cleaning property indicates the number of durable sheets at the time when some cleaning defects occur. As the image quality, the number of durable sheets at the time when even a slight amount of missing image (a phenomenon in which a toner amount is small in a fixed image in a solid portion and appears to be white) is generated is displayed.

4) Charge amount in three environments The charge amount in each environment was measured by the following method after leaving the toner and the carrier for one day under the following environmental conditions.

High temperature / high humidity (30 ° C / 80%), normal temperature / normal humidity (22 ° C / 60%), low temperature / low humidity (15 ° C / 10%)
Under each environment, the charge amount was measured according to the blow-off method as follows.

FIG. 10 is an explanatory view of an apparatus for measuring the triboelectric charge amount of toner or an external additive. The case where the measurement sample is toner will be described. 500 mesh screen 1 at the bottom
A mixture of toner and carrier having a weight ratio of 1:19 to be measured for triboelectrification amount is placed in a metal measuring container 102 including 03 in a polyethylene bottle having a volume of 50 to 100 ml and shaken by hand for 5 to 10 minutes. Then, about 0.5 to 1.5 g of the mixture (developer) is put and a lid 104 made of metal is placed. At this time, the total weight of the measurement container 102 is weighed and designated as W ₁ (g). Next, in the suction device 101 (at least the portion in contact with the measurement container 102 is an insulator), suction is performed from the suction port 107 to adjust the air volume control valve 106 to adjust the pressure of the vacuum gauge 105 to 250 mmAq. This state is sufficient, preferably 2
Suction for a minute to remove the toner by suction. The potential of the electrometer 109 at this time is V (volt). Where 1008
Is a capacitor and has a capacity of C (μF). The total weight of the measurement container after suction is weighed and is W ₂ (g). The triboelectric charge amount (mC / kg) of this toner is calculated by the following formula.

[0184]

(Equation 6)

5) Image Density Image density was measured by averaging five times with a Macbeth densitometer manufactured by Macbeth Co., and solid areas (image density = 1.
5) It represents the change value of the image density.

[0186]

The present invention will be described in more detail based on the following examples.

Example 1 Cyan toner particles used in this example were prepared as follows. Fast stirrer TK- homo with a mixer in a four-necked flask for two liters of ion-exchanged water was added to 710 parts by weight of 0.1 mol / liter -Na ₃ PO ₄ aqueous solution 450 parts by adjusting the rotational speed 12000rpm Then 65 ℃
It was heated to. 1.0 mol / liter-CaC
68 parts by weight of the ₁₂ aqueous solution was gradually added to prepare an aqueous dispersion medium containing a minute sparingly water-soluble dispersion stabilizer Ca ₃ (PO ₄ ) ₂ . On the other hand, the dispersoid system includes: styrene monomer 160 parts by weight n-butyl acrylate monomer 40 parts by weight cyan colorant (CI Pigment Blue 15: 3) 14 parts by weight polar resin 10 parts by weight [saturated polyester ( Terephthalic acid-propylene oxide-modified bisphenol A, acid value 15, peak molecular weight 6000)] Negative charge control agent (dialkyl salicylate metal compound) 2 parts by weight Release agent [ester wax] 40 parts by weight (melting point 59 ° C, Vickers hardness) 1.5)

The above mixture was dispersed for 3 hours using an attritor, and then 10 parts by weight of 2,2'-azobis (2,4-dimethylvaleronitrile) as a polymerization initiator was added to the polymerizable monomer composition. Was put into an aqueous dispersion medium, and granulation was carried out for 15 minutes while maintaining the rotation speed at 12000 rpm.
After that, the stirrer was changed from the high speed stirrer to the propeller stirrer, the internal temperature was raised to 80 ° C., and the polymerization was continued at 50 rpm for 10 hours. After the polymerization was completed, the slurry was cooled and diluted hydrochloric acid was added to remove the dispersion stabilizer. After further washing and drying, the weight average diameter is 6 μm, the coefficient of variation in the number distribution is 27%, the SF-1 is 104, and the SF-
Electrically insulating cyan toner particles of No. 2 were obtained. A schematic view of a tomographic photograph of the obtained cyan toner particles is shown in FIG. The structure showed that the ester wax as the release agent was covered with the outer shell resin (Mw 70,000, Mn 20,000) as the binder resin.

100 parts by weight of the obtained cyan toner particles and the hydrophobized inorganic fine powder (a-1) 1.
Cyan toner was prepared by mixing 2 parts by weight with 0.8 part by weight of the hydrophobized silicon compound fine powder (A) shown in Tables 2 and 3.

A two-component developer for magnetic brush development was prepared by mixing 6 parts by weight of the obtained cyan toner with 94 parts by weight of a resin-coated magnetic ferrite carrier having an average particle size of 50 μm. The prepared two-component developer was introduced into a modified full-color copying machine (CLC-500: manufactured by Canon Inc.) with a coating amount of silicone oil of 0.02 g / A4 size on a commercially available fixing machine, and cyan toner was replenished successively. Then, an image output test in a single color mode was performed. Table 4 shows the evaluation results.

The cyan toner of Example 1 was excellent in transferability, smoothly cleaned by the cleaning blade, and no filming was observed on the surface of the OPC photosensitive member. Furthermore, after a durability test of a large number of 50,000 sheets, the cyan toner on the developing sleeve was sampled, and the surface of each cyan toner particle was observed by an electron microscope. As a result, it was found that the inorganic fine powder of hydrophobic titanium oxide fine particles (a-1) The silicon compound fine powder (A) of the hydrophobic silica fine powder was present on the surfaces of the toner particles, and no deteriorated toner particles were found.

Comparative Example 1 Cyan toner particles prepared in the same manner as in Example 1 were mixed with the hydrophobicized inorganic fine powder (a-1) shown in Table 1 and the hydrophobicized silicon compound (shown in Tables 2 and 3). C) was mixed to prepare a cyan toner. Using the obtained cyan toner, a two-component developer for a magnetic brush was prepared in the same manner as in Example 1, and the evaluation results were obtained in the same manner as in Example 1. Table 4 shows the evaluation results.

The cyan toner of Comparative Example 1 was inferior in transferability to the cyan toner of Example 1, and filming occurred on the surface of the OPC photosensitive member. Furthermore, after the multi-sheet durability test, the cyan toner on the developing sleeve was sampled and the surface of each cyan toner particle was observed by an electron microscope. As a result, a large number of toner particles with a small amount of external additive on the toner particle surface were found.

Comparative Example 2 Hydrophobized inorganic fine powder (b-shown in Table 1 as an external additive
A cyan toner was prepared in the same manner as in Example 1 except that only 1) was used, and the evaluation results were obtained in the same manner as in Example 1. Table 4 shows the evaluation results.

Comparative Example 3 Hydrophobicized inorganic fine powder (b-
1) and the hydrophobized silicon compound fine powder (C) shown in Tables 2 and 3 were used to prepare a cyan toner in the same manner as in Example 1, and the same evaluation results as in Example 1 were obtained. I went. Table 4 shows the evaluation results.

Comparative Example 4 A cyan toner was prepared in the same manner as in Example 1 except that only the hydrophobized silicon compound fine powder (D) shown in Tables 2 and 3 was used as the external additive. Evaluation results were obtained in the same manner as in. Table 4 shows the evaluation results.

Comparative Example 5 A cyan toner was prepared in the same manner as in Example 1 except that only the hydrophobized inorganic fine powder (a-1) was used as the external additive, and evaluated in the same manner as in Example 1. The result was done. Table 4 shows the evaluation results.

Comparative Example 6 A cyan toner was prepared in the same manner as in Example 1 except that only the hydrophobized silicon compound fine powder (A) was used as the external additive, and the evaluation results were obtained in the same manner as in Example 1. I went.
Table 4 shows the evaluation results.

Comparative Example 7 A cyan toner was prepared in the same manner as in Example 1 except that only the hydrophobized silicon compound fine powder (B) was used as an external additive. I went.
Table 4 shows the evaluation results.

Comparative Example 8 A cyan toner was prepared in the same manner as in Example 1 except that only the hydrophobized silicon compound fine powder (C) was used as an external additive, and the evaluation results were obtained in the same manner as in Example 1. I went.
Table 4 shows the evaluation results.

Comparative Example 9 A cyan toner was prepared in the same manner as in Example 1 except that only the hydrophobized silicon compound fine powder (D) was used as an external additive. Evaluation results were obtained in the same manner as in Example 1. I went.
Table 4 shows the evaluation results.

Comparative Example 10 A cyan toner was prepared in the same manner as in Example 1 except that only the hydrophobized inorganic fine powder (b-2) was used as an external additive, and evaluated in the same manner as in Example 1. The result was done. Table 4 shows the evaluation results.

Comparative Example 11 A cyan toner was prepared in the same manner as in Example 1 except that only the hydrophobized inorganic fine powder (b-3) was used as an external additive, and evaluated in the same manner as in Example 1. The result was done. Table 4 shows the evaluation results.

Comparative Example 12 A cyan toner was prepared in the same manner as in Example 1 except that only the hydrophobized silicon compound fine powder (H) was used as an external additive, and the evaluation results were obtained in the same manner as in Example 1. I went.
Table 4 shows the evaluation results.

Comparative Example 13 A cyan toner was prepared in the same manner as in Example 1 except that only the hydrophobized silicon compound fine powder (I) was used as an external additive. I went.
Table 4 shows the evaluation results.

Example 2 In the same manner as in Example 1 except that the hydrophobized inorganic fine powder (a-1) and the hydrophobized silicon compound fine powder (B) shown in Tables 2 and 3 were used. A cyan toner was prepared, and the evaluation results were obtained in the same manner as in Example 1. Table 4 shows the evaluation results
Shown in

Example 3 A cyan toner was prepared in the same manner as in Example 1 except that the hydrophobized inorganic fine powder (a-2) and the hydrophobized silicon compound fine powder (E) were used. Evaluation results were obtained in the same manner as in Example 1. Table 4 shows the evaluation results.

Example 4 A cyan toner was prepared in the same manner as in Example 1 except that the hydrophobized inorganic fine powder (a-3) and the hydrophobized silicon compound fine powder (F) were used. Evaluation results were obtained in the same manner as in Example 1. Table 4 shows the evaluation results.

Example 5 A cyan toner was prepared in the same manner as in Example 1 except that the hydrophobized inorganic fine powder (a-4) and the hydrophobized silicon compound fine powder (G) were used. Evaluation results were obtained in the same manner as in Example 1. Table 4 shows the evaluation results.

[0210]

[Table 1]

[0211]

[Table 2]

[0212]

[Table 3]

[0213]

[Table 4]

Example 6 Styrene-n-butyl acrylate copolymer 200 parts by weight (Mw 70,000, Mn 20,000) Cyan colorant (CI Pigment Blue 15: 3) 14 parts by weight Polar resin 10 parts by weight [Saturated polyester (Terephtalic acid-propylene oxide-modified bisphenol A, acid value 15, peak molecular weight 6000)] Negative charge control agent (dialkyl salicylate metal compound) 2 parts by weight Release agent [ester wax] 10 parts by weight (melting point 59 ° C, Vickers Hardness 1.5)

After sufficiently melting and kneading the above composition using an extruder, the cooled kneaded material is mechanically coarsely pulverized, and the coarsely pulverized material is collided with a collision plate using a jet stream to finely pulverize it, and further the Coanda effect is obtained. The finely pulverized product was classified by an air flow classifier using a., The weight average particle size was 8.5 μm, the number variation coefficient was 37%, SF-1 was 152, and SF-2 was 145 indefinite cyan. Toner particles are obtained.

The cyan toner was prepared by mixing the obtained cyan toner particles, the hydrophobized inorganic fine powder (a-1), and the hydrophobized silicon compound fine powder (A). An evaluation test was conducted in the same manner as in. The evaluation results are shown in Table 6.

Example 7 Cyan toner particles prepared in the same manner as in Example 6 and commercial calcium phosphate fine powder were mixed with a Henschel mixer, and the obtained mixed powder was put into a container containing water. It was dispersed in water using a homomixer, and the water temperature was gradually raised to heat treatment at a temperature of 80 ° C. for 3 hours. Then, dilute hydrochloric acid was added to the container to sufficiently dissolve the calcium phosphate on the surface of the cyan toner particles. The cyan toner was filtered, washed, dried, and then passed through a 400-mesh sieve to remove agglomerates to obtain spherical cyan toner particles. The obtained cyan toner shows a spherical shape under an electron microscope and has a shape factor SF-1 of 109.
-2 is 120, the weight average diameter of the electrically insulating cyan toner is 7.7 μm, and the number variation coefficient is 28.
%Met.

Cyan toner was prepared by mixing the obtained cyan toner particles, the hydrophobized inorganic fine powder (a-1) and the hydrophobized silicon compound fine powder (A) to prepare a cyan toner. An evaluation test was conducted in the same manner as in. The evaluation results are shown in Table 6.

Example 8 The colorant was a C.I. I. Pigment Yellow 17, C.I. I. Pigment Red 202 and graft carbon black were used to obtain electrically insulating yellow toner particles, electrically insulating magenta toner particles, and electrically insulating black toner particles in the same manner as in Example 1. The physical properties of the toner particles of each color are shown in Table 5 below.

[0220]

[Table 5]

The resulting toner particles of each color, 1.2 parts by weight of the hydrophobized inorganic fine powder (a-1) and 0.8 parts by weight of the hydrophobized silicon compound fine powder (A) were mixed. To prepare each color toner. 6 parts by weight of the obtained toner of each color and a resin-coated magnetic ferrite carrier 9 having an average particle size of 50 μm
4 parts by weight were mixed to prepare a two-component developer for magnetic brush development.

Each of the prepared two-component color developers was used in a full-color copying machine (CLC-500: manufactured by Canon Inc.) modified with a silicone oil coating amount of 0.02 g / A4 size in a commercially available fixing machine. The toner was introduced into a developing device, toners of respective colors were replenished successively, and an image output test in a full color mode was conducted. Each color toner had a high transfer rate, and a good full-color copied image was obtained. Even in the multi-sheet durability test,
A good full-color copy image was obtained without cleaning failure. Table 6 shows the evaluation results of the yellow toner, the magenta toner, and the black toner which were subjected to the image output test in the single color mode.

Example 9 A two-component type developer for each color was prepared in the same manner as in Example 8 from each color toner prepared in the same manner as in Example 1 and Example 8 and the prepared two-component system development for each color. The developing agents 74-1, 74-2, 74-3 and 74 shown in FIG.
-4, a toner image of each color toner was formed under the image forming conditions described later by the magnetic brush developing method. The toner of each color toner image had a triboelectric charge amount of -15 to -18 mC / kg. The toner images of the respective colors are sequentially transferred from the photosensitive member 71 to the intermediate transfer member 75, and the four color toner images on the intermediate transfer member 75 are transferred to a transfer material (plain paper) having a basis weight of 199 g / m ² , and then transferred onto the transfer material. A toner image of four colors is heated and pressed by a fixing unit 81.
Thermal fixing was performed by.

After the toner image was transferred from the intermediate transfer body 75 to the transfer material, the intermediate transfer body 75 was sequentially cleaned by the cleaning means 80.

At this time, the transfer efficiency of each color toner from the photosensitive member 71 to the intermediate transfer member 75 is 97% to 99%, and the transfer efficiency from the intermediate transfer member 75 to the transfer material 76 is 99%. The transfer efficiency was as high as 96% to 98%.

A high-quality image having excellent color mixture and no hollow image was obtained. Further, double-sided images were formed, but no offset was observed on both the front and back surfaces of the transfer material. The durability test of 50,000 sheets was also conducted, but there was no change in the image density between the initial stage and the end stage, and no toner fusion to each member was observed.

A sectional view of the image forming apparatus used in this embodiment is shown in FIG. The photoconductor 71 has a photoconductive layer 71b having an organic photoconductor on a base material 71a, and rotates in a direction of an arrow, and rotates in a charging roller 72 (conductive elastic layer 72) facing and contacting.
The surface potential of about -600 V was charged on the photoconductor 71 with a and a cored bar 72b). The exposure 73 is turned on and off in accordance with digital image information on the photoconductor by a Porgon mirror so that the exposed portion potential is −100 V and the dark portion potential is −60.
An electrostatic charge image of 0 V is formed. A plurality of developing units 74-1,
Yellow toner using 74-2, 74-3, and 74-4,
A magenta toner, a cyan toner, or a black toner was used on the photoconductor 71 by a reversal development method to obtain a toner image.
The toner image has an intermediate transfer member 75 (elastic layer 75) for each color.
a, a four-color superposed color development image is formed on the intermediate transfer member 75 by being transferred onto the core metal 75b) as a support. Photoconductor 7
The transfer residual toner on No. 1 was collected in the residual toner container 79 by the cleaner member 78.

The intermediate transfer member 75 is a pipe-shaped core metal 75b.
Elastic layer 75 on which carbon black conductivity-imparting member is sufficiently dispersed in nitrile-butadiene rubber (NBR)
b was coated. The hardness of the coat layer 75b is J
According to IS K-6301, it was 30 degrees and the volume resistivity value was 10 ⁹ Ω · cm. The transfer current required for transfer from the photoconductor 71 to the intermediate transfer member 75 is about 5 μA,
This was obtained by applying + 500V from the power source on the cored bar 75b.

The transfer roller 77 having a diameter of 20 mm has a diameter of 1
A carbon conductivity imparting member was provided on a 0 mm core metal 77b with an ethylene-propylene-diene terpolymer (EPD).
M) which has an elastic layer 77a produced by coating a sufficiently dispersed foam.
The volume resistivity value of a is 10 ⁶ Ω · cm, and JIS K-
As for the hardness of 6301 standard, one having a value of 35 degrees was used.
A voltage was applied to the transfer roller and a transfer current of 15 μA was passed.

Table 6 shows the evaluation results of the respective color toners subjected to the image output test in the single color mode.

Comparative Example 14 Hydrophobicized inorganic fine powder (a-1) as an external additive,
Toners of the respective colors were prepared in the same manner as in Example 9 except that the hydrophobized silicon compound fine powder (C) was used, and the evaluation test was performed in the same manner as in Example 9. The evaluation results are shown in Table 6.

Comparative Example 15 Toners of respective colors were prepared in the same manner as in Example 9 except that only the hydrophobized inorganic fine powder (a-1) was used as the external additive, and the evaluation test was conducted in the same manner as in Example 9. Was done. The evaluation results are shown in Table 6.

Example 10 Styrene 160 parts by weight n-Butyl acrylate 40 parts by weight Hydrophobized magnetic iron oxide 95 parts by weight Average particle size = 0.25 μm Under 10 K oersted Saturation magnetization = 65 emu / g Remanent magnetization = 12 emu / G Coercive force = 115 Oersted styrene-methacrylic acid-methyl methacrylate 11 parts by weight Monomer weight ratio = 85: 5: 10 Weight average molecular weight = about 57,000 Divinylbenzene 3 parts by weight Di-t-butylsalicylic acid metal compound 3 parts by weight Low Molecular weight polypropylene wax (mp = 70 ° C) 15 parts by weight

The above formulation was heated to 60 ° C. and uniformly dissolved and dispersed at 12000 rpm using a TK homomixer. In addition to this, the polymerization initiator 2,2′-azobis (2,2
9 parts by weight of 4-dimethylvaleronitrile) was dissolved to prepare a polymerizable monomer composition.

On the other hand, 650 parts by weight of deionized water was added with 0.
Add 510 parts by weight of 1M-Na ₃ PO ₄ aqueous solution, and add 60 ° C.
After heating to TK homomixer (made by Tokushu Kika Kogyo)
And was stirred at 12000 rpm. 1.
75 parts by weight of 0M-CaCl ₂ aqueous solution was gradually added, and C
An aqueous medium containing a ₃ (PO ₄ ) ₂ was prepared.

The above polymerizable monomer composition was put into the above aqueous medium and stirred at 60 ° C. under N ₂ atmosphere with a TK type homomixer at 10,000 rpm for 25 minutes to give the polymerizable monomer composition. Granulated. Then, while stirring with a paddle stirring blade, the temperature was raised to 80 ° C. and the reaction was performed for 10 hours. After the completion of the polymerization reaction, the mixture was cooled, hydrochloric acid was added to dissolve calcium phosphate, and the mixture was filtered, washed with water and dried to obtain a magnetic toner.

The obtained magnetic toner particles have a weight average particle diameter of 6.5 μm, a coefficient of variation of 25 and SF-1.
Was 105 and SF-2 was 109.

100 parts by weight of magnetic toner particles, 1.1 parts by weight of hydrophobized inorganic fine powder (a-1), and 0.7 parts by weight of hydrophobized silicon compound fine powder are mixed to obtain a magnetic toner. Was prepared.

Commercially available electrophotographic copying machine (NP-8582:
Using a modified machine manufactured by Canon Inc., images of durability of 50,000 sheets were printed, and fixing property, anti-offset property, cleaning property, toner charge amount, image density change and image quality change were evaluated.

[0240]

[Table 6]

[0241]

INDUSTRIAL APPLICABILITY The present invention can provide a toner for developing an electrostatic image which is excellent in transferability and cleaning property and is excellent in durability of a large number of sheets with less deterioration of external additives.

[Brief description of drawings]

FIG. 1 is a graph showing the particle size distribution of hydrophobized silica fine powder (A).

FIG. 2 is a graph showing the particle size distribution of hydrophobized silica fine powder (B).

FIG. 3 is a graph showing a particle size distribution of hydrophobized silica fine powder (C).

FIG. 4 is a graph showing the particle size distribution of hydrophobized silica fine powder (D).

FIG. 5 is a schematic explanatory view showing a specific example of an image forming apparatus to which a two-component developer for magnetic brush development prepared by mixing the toner for developing an electrostatic image of the present invention with a magnetic carrier can be applied. .

FIG. 6 is a schematic explanatory diagram showing a specific example of a full-color copying machine.

FIG. 7 is a schematic explanatory view showing a specific example of an image forming apparatus having an intermediate transfer member.

FIG. 8 is a diagram for explaining (A) toner shape factor SF-1 and (B) toner shape factor SF-2.

FIG. 9 is a view showing an example of a cross section of toner particles encapsulating a release agent.

FIG. 10 is a schematic explanatory diagram for measuring a triboelectric charge amount of a sample.

Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI Technical indication location G03G 9/08 384 (72) Inventor Takehiko Chiba 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (23)

[Claims] 1. (a) Toner particles having a weight average particle diameter of 1 to 9 μm, (b) Hydrophobicized inorganic fine powder having an average particle diameter of 10 to 90 nm, and (c) Hydrophobicized silicon compound fine powder. The toner for developing an electrostatic image having at least the following, wherein the hydrophobized silicon compound fine powder has an average particle size of 30 to
120 nm, containing 15 to 45% by number of silicon compound particles having a particle size of 5 to 30 nm, containing 30 to 70% by number of silicon compound particles having a particle size of 30 to 60 nm, and having a particle size of 60 n
A toner for developing an electrostatic charge image, comprising 5 to 45% by number of silicon compound particles of m or more. 2. The toner particles have a shape factor SF-1 of 10.
0 to 150, and the shape factor SF-2 is 100 to 140
The toner according to claim 1, which is 3. The toner particles have a shape factor SF-1 of 10.
0 to 140, and the shape factor SF-2 is 100 to 130
The toner according to claim 2, wherein 4. The toner particles have a shape factor SF-1 of 10.
0 to 130, and the shape factor SF-2 is 100 to 125
The toner according to claim 3, wherein 5. The toner particles have a weight average particle diameter of 2 to 8 μm.
The toner according to claim 1, further comprising: 6. The toner according to claim 1, wherein the hydrophobized inorganic fine powder has an average particle size of 20 to 80 nm. 7. The hydrophobized inorganic fine powder comprises titanium oxide, aluminum oxide, strontium titanate, cerium oxide, magnesium oxide, silicon nitride, silicon carbide, calcium sulfate, barium sulfate, calcium carbonate and fluorocarbon. The toner according to claim 1, which is a fine powder formed of a material selected from the group consisting of: 8. The toner according to claim 1, wherein the hydrophobized inorganic fine powder is hydrophobized titanium oxide fine powder. 9. The toner particles have toner particles obtained by polymerizing a polymerizable monomer composition containing at least a polymerizable monomer, a release agent and a colorant in an aqueous medium. The toner according to claim 1. 10. The toner according to claim 9, wherein the toner particles contain at least a binder resin, a release agent and a colorant. 11. The toner according to claim 9, wherein the toner particles contain a release agent in an amount of 10 to 40 parts by weight based on 100 parts by weight of a binder resin. 12. The toner particles have a shape factor SF-1 of 1.
0 to 150 and the shape factor SF-2 is 100 to 14
The toner according to claim 11, which is 0. 13. The toner particles have a shape factor SF-1 of 1.
0 to 140, and the shape factor SF-2 is 100 to 13
The toner according to claim 12, which is 0. 14. The toner particles have a shape factor SF-1 of 1.
0 to 130, and the shape factor SF-2 is 100 to 12
14. The toner according to claim 13, which is 5. 15. The toner particles have a weight average particle diameter of 2 to 8.
The toner according to any one of claims 9 to 14, wherein the average particle diameter of the hydrophobic inorganic fine powder is 20 to 80 nm. 16. Hydrophobized inorganic fine powder is contained in an amount of 0.05 to 3.5 parts by weight based on 100 parts by weight of toner particles, and hydrophobized silicon compound fine powder is 0.0.
The toner according to claim 1, wherein the toner is contained in an amount of 5 to 1.5 parts by weight. 17. The toner according to claim 1, wherein the hydrophobized silicon compound fine powder is hydrophobized silica fine powder or silicone resin fine powder. 18. The release agent is paraffin wax, polyolefin wax, higher fatty acid, higher fatty acid metal salt,
The toner according to any one of claims 9 to 17, which is a compound selected from the group consisting of long-chain alkyl alcohols, amide waxes, ester waxes, and polymethylene waxes. 19. The toner according to claim 1, wherein the hydrophobized silicon compound fine powder contains 45 to 70% by number of particles having a particle diameter of 30 to 60 nm. 20. The toner according to claim 19, wherein the hydrophobized silicon compound fine powder contains 50 to 70% by number of particles having a particle diameter of 30 to 60 nm. 21. The hydrophobized inorganic fine powder has an absolute value of triboelectric charge of 45 mC / kg or less, and the hydrophobized silicon compound fine powder has an absolute value of triboelectric charge of 50 to 3;
The toner according to any one of claims 1 to 20, which has a viscosity of 00 mC / kg. 22. The hydrophobized inorganic fine powder has an absolute value of triboelectric charge amount of 30 mC / kg or less, and the hydrophobized silicon compound fine powder has an absolute value of triboelectric charge amount of 70-2.
The toner according to claim 21, which has a viscosity of 50 mC / kg. 23. The hydrophobicized inorganic fine powder has a hydrophobicity of 20 to 80%, and the hydrophobicized silicon compound fine powder has a hydrophobicity of 30 to 80%.
The toner according to any one of 1.