JP2009175578A - Toner for image formation and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a toner having a small particle diameter and sharp particle diameter distribution, which can give high picture quality with excellent reproducibility of minute dots; and to provide a toner having excellent low temperature fixability, causing little deposition of a toner component on a member even in long-term use and preventing problems such as reduction in chargeability. <P>SOLUTION: The toner for image formation contains at least a release agent and is characterized in that:(1) the release agent comprises a hydrocarbon wax having a melting point of 60°C to 90°C; (2) the toner shows heat absorption in a range from 3.5 to 5.5 J/g at an endothermic peak derived from the release agent in DC measurement of the toner; (3) the toner has an average circularity of ≥0.94 and a ratio (D/S) of a contact area (D) to the whole projected area (S) of the toner in a range from 15 to 40%; and (4) a charge controlling agent is fixed on surfaces of the toner particles. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a toner used as a developer for developing an electrostatic image in electrophotography, electrostatic recording, electrostatic printing and the like, and an electrophotographic developing apparatus using the toner. More particularly, the present invention relates to an electrophotographic toner and an image forming apparatus used for a copying machine, a laser printer, a plain paper fax machine, and the like using a direct or indirect electrophotographic developing system.

In recent years, the strong demand for higher image quality from the market has spurred the development of an electrophotographic apparatus suitable for it and a toner developer used therefor. As a toner corresponding to high image quality, it is essential that the toner has a uniform particle size. When the toner particle size is uniform and the particle size distribution becomes sharp, the behavior of individual toner particles during development is aligned, and the reproducibility of minute dots is remarkably improved.
However, a toner having a smaller particle size and a uniform particle size is more difficult to clean than before. Particularly with blade cleaning, it is difficult to stably clean toner having a uniform and small particle diameter. Under such circumstances, various methods for improving the cleaning property by devising the toner have been proposed. One of them is a method of changing the toner from a spherical shape to an irregular shape. By changing the shape of the toner, the powder fluidity of the toner is lowered, and it is easy to stop by blade cleaning. However, if the degree of toner irregularity is too large, the behavior of the toner becomes unstable during development and the like, and the fine dot reproducibility deteriorates.

As described above, by changing the shape of the toner, the reliability of the toner for cleaning is certainly improved, but on the other hand, there is a problem in terms of fixing. In other words, when the shape of the toner is made irregular, the toner filling density in the toner layer on the transfer material before fixing becomes small, the thermal conductivity in the toner layer becomes slow during fixing, and the low-temperature fixability deteriorates. Resulting in. In particular, when the pressure at the time of fixing is smaller than the conventional pressure, the thermal conductivity is further deteriorated and the low-temperature fixing is hindered.
Patent Document 1 proposes a toner made of polyester having a Wadell practical sphericity of 0.90 to 1.00. However, since the toner is substantially spherical, the above-described problem of toner cleaning properties is solved. Not.

  In addition to suspension polymerization, there are emulsion polymerization methods and dissolution suspension methods that are relatively easy to modify, but also in the emulsion polymerization method, complete removal of styrene monomers and removal of emulsifiers and dispersants are possible. It is difficult, and the problem with toners is becoming increasingly greater as environmental problems have become particularly close. Also, in the toner shape, the contamination of the photoreceptor due to the toner is caused by the fact that the concave portion of the silica added as a fluidizing agent is weakly adhered to the concave portion and the silica moves to the concave portion during use. And the problem of toner adhesion to the fixing roller are likely to occur. In addition, the dissolution suspension method has the advantage that a polyester resin that can be fixed at low temperature can be used, but in order to achieve oil-less fixing, the polymer and color are controlled during production and control of the polymer to widen the mold release width. Since the high molecular weight component is added in the step of dissolving or dispersing the agent in the solvent, the viscosity of the liquid rises and productivity problems are likely to occur. And those problems are not solved yet. In particular, in the solution suspension method, in Patent Document 2, the toner surface shape is made spherical and uneven to improve the cleaning. However, since it is an irregularly shaped toner having no regularity, charging stability is affected. Furthermore, a toner having satisfactory quality has not been obtained because a high molecular weight design for ensuring basic durability and releasability has not been achieved.

In order to control the charging of the toner, a large amount of charge adjusting agent is added. After melt-kneading a thermoplastic resin as a binder resin with a colorant and additives used as required. In the method of producing toner by pulverization and classification, so-called pulverization method, (1) there is a limit to reducing the particle size and the image quality becomes severe, (2) kneading ⇒inside each particle for pulverization Although it can be dispersed uniformly, it is impossible to control the arrangement of materials in the particles. (3) If the amount is increased in order to impart chargeability to the charge control agent, side effects on filming / fixing properties will occur. Such problems occur.
JP 2003-091100 A JP 2003-098741 A JP 2003-140391 A Japanese Patent No. 3631468

The subject of this invention is as follows. (1) To provide a toner having a small particle size and a sharp particle size distribution capable of obtaining a high quality image with excellent reproducibility of minute dots.
(2) Toner having excellent low-temperature fixability and less adhesion of a toner component to a member even during long-term use, and causing no trouble such as a decrease in charging ability.

The present inventors have completed the present invention to solve the above-described problems. That is, according to the present invention, the following toner, an image forming method and an image forming apparatus using the toner are provided.
[1] In a toner containing at least a release agent,
(1) The toner contains the release agent, and the release agent is a hydrocarbon wax having a melting point of 60 to 90 ° C.
(2) The endothermic peak of the endothermic peak derived from the release agent in the DSC measurement of the toner is in the range of 3.5 to 5.5 J / g,
(3) The average circularity of the toner is 0.94 or more, and the ratio (D / S) of the ground contact area (D) to the total projected area (S) of the toner is 15 to 40%,
(4) An image forming toner, wherein a charge control agent is fixed on the surface of the toner particles.
[2] The image forming toner according to [1], wherein the ground contact area (D) is a total area of contact surfaces of the toner with a target surface.

[3] When the toner is placed on a horizontal glass flat plate by dropping the toner from a position 10 cm above the glass flat plate with a mesh of 22 μm and sieving for 10 seconds. The image forming toner according to [1] or [2], defined as a total area of a contact surface with the glass flat plate.
[4] In at least one of the portions where the toner is in contact with the glass flat plate, the ratio (L / M) of the major axis L to the minor axis M of the contact portion is such that (L / M)> 2. The image forming toner according to any one of [1] to [3], wherein
[5] A toner material liquid in which at least a polyester prepolymer having a functional group containing a nitrogen atom, polyester, a colorant, a release agent, and an inorganic filler is dispersed in an organic solvent is crosslinked and / or in an aqueous medium. Or an image forming toner obtained by an extension reaction, wherein the toner has a shape factor SF-1 in the range of 130 to 160 and a shape factor SF-2 in the range of 110 to 140. The toner for image formation as described in any one of [1] to [4] above.

[6] The toner has a volume average particle diameter (Dv) of 3 to 8 μm and a ratio (Dv / Dn) of the volume average particle diameter (Dv) to the number average particle diameter (Dn) of 1.00 to 1.n. The image forming toner according to any one of [1] to [5], wherein the toner is in the range of 30.
[7] The toner according to any one of [1] to [6], wherein the inorganic filler is montmorillonite or a modified product thereof. The toner for image formation as described.
[8] The toner according to any one of [1] to [7], wherein the toner is a toner obtained by externally adding fine particles having an average primary particle size of 50 to 500 nm to the surface of the toner base particles. The toner for image formation as described.
[9] The toner for image formation as described in any one of [1] to [8] above, wherein the toner has a glass transition point of 40 to 60 ° C.
[10] The image-forming toner as described in any one of [1] to [9] above, wherein 1 to 10% by number of particles of 2 μm or less of the toner is present.
(11) An image forming method using the toner according to any one of (1) to (10).
(12) An image forming apparatus using the toner according to any one of (1) to (10) as an electrostatic charge image forming unit.

  The dry toner of the present invention is excellent in low-temperature fixability, has little residual toner in an apparatus using blade cleaning, and gives an image with high image quality and high resolution.

The present invention has the following features.
To secure releasability between the fixing roller and the toner surface, a toner containing a WAX component is used. However, the WAX component adheres to other members such as a photoconductor during long-term printing, leading to a decrease in image quality. It has been known. For this reason, coexistence of suppression of WAX adhesion to other members and securing of fixing releasability becomes a problem.
By reducing the amount of the WAX component in the toner, the adhesion of WAX is suppressed, but it is difficult to ensure the fixing releasability.
Therefore, as an amount that can sufficiently secure the fixing releasability, the endothermic amount of the endothermic peak derived from the releasing agent in DSC measurement is in the range of 3.5 to 5.5 J / g, and the melting point is 60 to 90. By using the hydrocarbon-based WAX at 0 ° C., it is possible to ensure fixing releasability while suppressing the adhesion of WAX to other members.

  In the present invention, the liquid containing the toner material is preferably dissolved or dispersed in a solvent. The solvent preferably contains an organic solvent. The organic solvent is preferably removed when forming the toner base particles or after forming the toner base particles.

  The organic solvent can be appropriately selected according to the purpose, but since the removal is easy, the boiling point is preferably less than 150 ° C. Specifically, toluene, xylene, benzene, carbon tetrachloride, methylene chloride, 1,2-dichloroethane, 1,1,2-trichloroethane, trichloroethylene, chloroform, monochlorobenzene, dichloroethylidene, methyl acetate, ethyl acetate, methyl ethyl ketone, And methyl isobutyl ketone. Of these, toluene, xylene, benzene, methylene chloride, 1,2-dichloroethane, chloroform, carbon tetrachloride and the like are preferable, and ethyl acetate is particularly preferable. These may be used alone or in combination of two or more.

  The amount of the organic solvent used can be appropriately selected according to the purpose, but is preferably 40 to 300 parts by mass, more preferably 60 to 140 parts by mass, and further 80 to 120 parts by mass with respect to 100 parts by mass of the toner material. preferable.

The modified inorganic compound in the toner material is preferably one in which at least a part of the metal cations of the layered inorganic compound is modified with organic ions.
Examples of organic ion modifiers of layered inorganic minerals (compounds) in which at least some of the ions of the layered inorganic compound are modified with organic ions include quaternary alkyl ammonium salts, phosphonium salts and imidazolium salts. However, quaternary alkyl ammonium salts are preferred. Examples of the quaternary alkylammonium include trimethylstearylammonium, dimethylstearylbenzylammonium, dimethyloctadecylammonium, oleylbis (2-hydroxyethyl) methylammonium and the like.

  Examples of the organic ion modifier include branched, unbranched or cyclic alkyl (C1-C44), alkenyl (C1-C22), alkoxy (C8-C32), hydroxyalkyl (C2-C22), ethylene oxide, propylene oxide, and the like. Examples include sulfates, sulfonates, carboxylates, or phosphates. A carboxylic acid having an ethylene oxide skeleton is desirable.

Commercially available layered inorganic minerals partially modified with an organic cation include Bentone 3, Bentone 38, Bentone 38V (above, manufactured by Leox), Thixogel VP (manufactured by United catalyst), Kraton 34, Kraton 40, Kraton XL Quartium 18 bentonite such as (made by Southern Clay), and stearalkonium bentonite such as Bentone 27 (made by Leox), Thixogel LG (made by United catalyst), Clayton AF, Clayton APA (made by Southern Clay) Quaternium 18 / benzalkonium bentonite such as Clayton HT and Clayton PS (manufactured by Southern Clay). Particularly preferred are Clayton AF and Clayton APA. Moreover, as a layered inorganic mineral partially modified with an organic anion, a material obtained by modifying DHT-4A (manufactured by Kyowa Chemical Industry Co., Ltd.) with an organic anion represented by the following general formula (1) is particularly preferable. The following general formula (1) includes, for example, Hytenol 330T (Daiichi Kogyo Seiyaku Co., Ltd.).
Formula (1) R ₁ (OR ₂ ) _n OSO ₃ M
[Wherein, R ₁ represents an alkyl group having 13 carbon atoms, and R ₂ represents an alkylene group having 2 to 6 carbon atoms. n represents an integer of 2 to 10, and M represents a monovalent metal element]

  In the toner of the present invention, the ratio (Dv / Dn) of the volume average particle diameter (Dv) to the number average particle diameter (Dn) is 1.00 to 1.30, which is high resolution and high image quality. It is possible to obtain the toner. Furthermore, in the case of a two-component developer, even if a long-term balance of the toner is performed, fluctuations in the particle size of the toner in the developer are reduced, and good and stable developability even with long-term stirring in the developing device. Is possible.

  In the toner of the present invention, the volume average particle diameter Dv is preferably 3.0 to 8.0 μm. In general, it is said that the smaller the particle size of the toner, the more advantageous it is to obtain a high-resolution and high-quality image, but it is disadvantageous for transferability and cleaning properties. is there. When the volume average particle diameter is smaller than the above range, in the case of a two-component developer, the toner is fused to the surface of the carrier during a long period of stirring in the developing device, and the charging ability of the carrier is reduced. When it is used, toner filming on the developing roller and toner fusion to a member such as a blade for thinning the toner are likely to occur. In addition, these phenomena are greatly related to the content of fine powder. In particular, when the particle size of 2 μm or less exceeds 20%, it becomes an obstacle to the adhesion to the carrier and the high level of charging stability. Conversely, when the toner particle size is larger than the above range, it becomes difficult to obtain a high-resolution and high-quality image, and the toner particle size when the balance of the toner in the developer is performed. In many cases, fluctuations of

As described above, a toner having a small particle size and a uniform particle size causes difficulty in cleaning properties, and thus the circularity is preferably 0.93 to 0.97.
First, the relationship between toner shape and transferability will be described. When using a full-color copier that transfers images with multi-color development, the amount of toner on the photoconductor increases compared to the case of one-color black toner used in black-and-white copiers. It is difficult to improve transfer efficiency. In addition, when ordinary irregular toner is used, a shearing force or friction between the photosensitive member and the cleaning member, between the intermediate transfer member and the cleaning member, and / or between the photosensitive member and the intermediate transfer member. Due to the force, toner fusing or filming occurs on the surface of the photoreceptor or the intermediate transfer member, and transfer efficiency tends to deteriorate. When generating a full-color image, it is difficult to transfer the four-color toner images uniformly. Further, when an intermediate transfer member is used, problems are likely to occur in terms of color unevenness and color balance, and a high-quality full-color image is stabilized. Output is not easy.

  From the viewpoint of the balance between blade cleaning and transfer efficiency, the toner circularity is 0.93 to 0.97, so that both cleaning and transferability can be achieved. Cleaning and transferability are greatly related to the material of the blade and how to apply the blade, and transfer also varies depending on the process conditions, so that the design according to the process can be performed within the above range. However, if the toner circularity exceeds 0.97, cleaning with a blade becomes difficult. On the other hand, when the circularity is less than 0.93, the above-mentioned transferability is deteriorated.

(Toner particle size)
The average particle size and particle size distribution of the toner are determined by the Coulter counter method. Examples of the measuring device for the particle size distribution of toner particles include Coulter Counter TA-II and Coulter Multisizer II (both manufactured by Coulter). In the present invention, measurement was performed using a Coulter Counter TA-II type connected to an interface (Nichiken Giken) that outputs number distribution and volume distribution and a PC9801 personal computer (manufactured by NEC).

The measurement method is described below.
First, 0.1 to 5 ml of a surfactant (preferably alkylbenzene sulfonate) is added as a dispersant to 100 to 150 ml of an aqueous electrolytic solution. Here, the electrolytic solution is a solution prepared by preparing a 1% NaCl aqueous solution using primary sodium chloride. For example, ISOTON-II (manufactured by Coulter) can be used. Here, 2 to 20 mg of a measurement sample is further added. The electrolytic solution in which the sample is suspended is subjected to a dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes. Volume distribution and number distribution are calculated.

  As channels, 2.00 to less than 2.52 μm; 2.52 to less than 3.17 μm; 3.17 to less than 4.00 μm; 4.00 to less than 5.04 μm; 5.04 to less than 6.35 μm; 6 Less than 35 to 8.00 μm; less than 8.00 to less than 10.08 μm; less than 10.08 to less than 12.70 μm; less than 12.70 to less than 16.00 μm; less than 16.00 to less than 20.20 μm; Uses 13 channels of less than 40 μm; 25.40 to less than 32.00 μm; 32.00 to less than 40.30 μm, and targets particles having a particle size of 2.00 μm to less than 40.30 μm. The volume-based volume average particle diameter (Dv) obtained from the volume distribution according to the present invention and the number average particle diameter (Dn) obtained from the number distribution and the ratio Dv / Dn were obtained.

  The glass transition point of the toner of the present invention is preferably 40 to 60 ° C. in order to obtain low temperature fixability, heat resistant storage stability and high durability. That is, when the glass transition point is less than 40 ° C., blocking in the developing machine and filming to the photosensitive member are likely to occur, and when it exceeds 60 ° C., the low-temperature fixability tends to be deteriorated.

The glass transition point of the present invention is measured with a Rigaku THRMOFLEX TG8110 manufactured by Rigaku Corporation at a temperature increase rate of 10 ° C./min.
A method for measuring Tg will be outlined. As an apparatus for measuring Tg, a TG-DSC system TAS-100 manufactured by Rigaku Corporation was used.
First, about 10 mg of a sample is placed in an aluminum sample container, which is placed on a holder unit and set in an electric furnace. First, after heating from room temperature to 150 ° C. at a temperature rising rate of 10 ° C./min, the sample was allowed to stand at 150 ° C. for 10 minutes, the sample was cooled to room temperature and left for 10 minutes, and the temperature rising rate was again increased to 150 ° C. under a nitrogen atmosphere. DSC measurement was performed by heating at min. Tg was calculated from the tangent of the endothermic curve near the Tg and the base line using the analysis system in the TAS-100 system.

(Release agent)
In the present invention, the release agent needs 3.5-5.5 J / g as the endothermic amount of the endothermic peak derived from the release agent in the DSC measurement in the toner. If it is less than 3.5 J / g, the desired releasability cannot be obtained and the fixability is deteriorated. Moreover, when it exceeds 5.5 J / g, there is a problem such as filming. As the wax used in the toner of the present invention, a low melting point wax having a melting point of 60 to 90 ° C. works more effectively as a release agent in the dispersion with the binder resin between the fixing roller and the toner interface, As a result, the fixing roller is effective against high-temperature offset resistance without applying a release agent such as oil.
The melting point of the wax in the present invention was the maximum endothermic peak measured by a differential scanning calorimeter (DSC).
The wax material is most preferably a hydrocarbon wax from the viewpoint of compatibility with the binder resin.

(Coloring agent)
As the colorant used in the present invention, all known dyes and pigments can be used. For example, carbon black, nigrosine dye, iron black, naphthol yellow S, Hansa yellow (10G, 5G, G), cadmium yellow, yellow Iron oxide, ocher, yellow lead, titanium yellow, polyazo yellow, oil yellow, Hansa yellow (GR, A, RN, R), pigment yellow L, benzidine yellow (G, GR), permanent yellow (NCG), Vulcan fast Yellow (5G, R), Tartrazine Lake, Quinoline Yellow Lake, Anthrazan Yellow BGL, Isoindolinone Yellow, Bengala, Red Tan, Lead Zhu, Cadmium Red, Cadmium Mercury Red, Antimon Zhu, Permanent Red 4R , Para red, phissa red, parac Luort Nitroaniline Red, Resol Fast Scarlet G, Brilliant Fast Scarlet, Brilliant Carnmin BS, Permanent Red (F2R, F4R, FRL, FRLL, F4RH), Fast Scarlet VD, Belkan Fast Rubin B, Brilliant Scarlet G, Resol Rubin GX, Permanent Red F5R, Brilliant Carmine 6B, Pogment Scarlet 3B, Bordeaux 5B, Tolujing Maroon, Permanent Bordeaux F2K, Helio Bordeaux BL, Bordeaux 10B, Bon Maroon Light, Bon Maroon Medium, Eosin Lake, Rhodamine Lake B, Rhodamine Lake Y, Alizarin Lake, Thioindigo Red B, Thioindigo Maroon, Oil Red, Quinacridone Red, Pi Zoron Red, Polyazo Red, Chrome Vermilion, Benzidine Orange, Perinone Orange, Oil Orange, Cobalt Blue, Cerulean Blue, Alkaline Blue Lake, Peacock Blue Lake, Victoria Blue Lake, Metal Free Phthalocyanine Blue, Phthalocyanine Blue, Fast Sky Blue, Indance Ren Blue (RS, BC), Indigo, Ultramarine Blue, Bituminous Blue, Anthraquinone Blue, Fast Violet B, Methyl Violet Lake, Cobalt Purple, Manganese Purple, Dioxane Violet, Anthraquinone Violet, Chrome Green, Zinc Green, Chrome Oxide, Pyridian, Emerald Green , Pigment Green B, Naphthol Green B, Green Gold, Acid Green Lake, Malachite Grits Nreki, phthalocyanine green, anthraquinone green, titanium oxide, zinc white, lithopone and mixtures thereof can be used. The content of the colorant is usually 1 to 15% by mass, preferably 3 to 10% by mass with respect to the toner.

The colorant used in the present invention can also be used as a master batch combined with a resin.
As the binder resin to be kneaded together with the production of the masterbatch or the masterbatch, in addition to the above-mentioned modified and unmodified polyester resins, styrene such as polystyrene, poly p-chlorostyrene, polyvinyltoluene, and substituted polymers thereof; Styrene-p-chlorostyrene copolymer, styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer Styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-α- Chloromethyl methacrylate copolymer, Tylene-acrylonitrile copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer, styrene-maleic acid copolymer, styrene-malein Styrene copolymers such as acid ester copolymers; polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, epoxy resin, epoxy polyol resin, polyurethane, polyamide, polyvinyl butyral, poly Acrylic resin, rosin, modified rosin, terpene resin, aliphatic or alicyclic hydrocarbon resin, aromatic petroleum resin, chlorinated paraffin, paraffin wax, etc. The

  This master batch can be obtained by mixing and kneading a resin for a master batch and a colorant under a high shear force to obtain a master batch. At this time, an organic solvent can be used to enhance the interaction between the colorant and the resin. Also, a so-called flushing method called watering paste containing water of a colorant is mixed and kneaded together with a resin and an organic solvent, and the colorant is transferred to the resin side to remove moisture and organic solvent components. Since it can be used as it is, it does not need to be dried and is preferably used. For mixing and kneading, a high shear dispersion device such as a three-roll mill is preferably used.

  A method for producing an electrophotographic toner in which particles comprising a colorant and a resin and particles comprising at least charge control agent particles are mixed together in a container using a rotating body in order to adhere and fix the charge control agent on the toner particle surface However, in this method, the object of the present invention is to include a step of mixing at a peripheral speed of the rotating body of 40 to 150 m / sec in a container without a fixing member protruding from the inner wall of the container. Toner particles are obtained.

  Known charge control agents can be used, such as nigrosine dyes, triphenylmethane dyes, chromium-containing metal complex dyes, molybdate chelate pigments, rhodamine dyes, alkoxy amines, quaternary ammonium salts (fluorine-modified 4 Secondary ammonium salts or compounds, tungsten simple substances or compounds, fluorine activators, salicylic acid metal salts, and metal salts of salicylic acid derivatives. Specifically, Nitronine-based dye Bontron 03, quaternary ammonium salt Bontron P-51, metal-containing azo dye Bontron S-34, oxynaphthoic acid metal complex E-82, salicylic acid metal complex E- 84, E-89 of a phenol-based condensate (manufactured by Orient Chemical Industry Co., Ltd.), TP-302 of a quaternary ammonium salt molybdenum complex, TP-415 (manufactured by Hodogaya Chemical Industry Co., Ltd.), quaternary ammonium Copy charge PSY VP2038 of salt, copy blue PR of triphenylmethane derivative, copy charge of quaternary ammonium salt NEG VP2036, copy charge NX VP434 (manufactured by Hoechst), LRA-901, LR-147 which is a boron complex (Nippon Carlit), copper phthalocyanine, perylene, quinaclide And azo pigments, and other high molecular compounds having a functional group such as a sulfonic acid group, a carboxyl group, and a quaternary ammonium salt.

  In the present invention, the amount of charge control agent used is determined by the toner production method including the type of binder resin, the presence or absence of additives used as necessary, and the dispersion method, and is uniquely limited. However, it is preferably used in the range of 0.1 to 10 parts by mass with respect to 100 parts by mass of the binder resin. Preferably, the range of 0.2-5 mass parts is good. When the amount exceeds 10 parts by mass, the chargeability of the toner is too high, the effect of the main charge control agent is reduced, the electrostatic attraction with the developing roller is increased, the flowability of the developer is reduced, and the image density is reduced. Incurs a decline. These charge control agents and mold release agents can be melt-kneaded together with the masterbatch and resin, and of course, they may be added when dissolved and dispersed in an organic solvent.

An external additive is used to assist the fluidity, developability, and chargeability of the colored particles obtained in the present invention. As this external additive, an inorganic filler can be preferably used. The primary particle diameter of the inorganic filler is preferably 5 m to 2 m, and particularly preferably 5 m to 500 m. Moreover, it is preferable that the specific surface area by BET method is 20-500 m < ² > / g. The proportion of the inorganic filler used is preferably 0.01 to 5% by mass of the toner, and particularly preferably 0.01 to 2.0% by mass. Specific examples of the inorganic filler include, for example, silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, tin oxide, quartz sand, clay, mica, wollastonite, diatomaceous earth. Examples include soil, chromium oxide, cerium oxide, pengala, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, and silicon nitride. Among these, as the fluidity imparting agent, it is preferable to use hydrophobic silica fine particles and hydrophobic titanium oxide fine particles in combination. In particular, when stirring and mixing is performed using an average particle size of both fine particles of 50 mμ or less, the electrostatic force and van der Waals force with the toner are remarkably improved, so that a desired charge level is obtained. It is clear that even with stirring and mixing inside the developing machine, a fluidity-imparting agent is not detached from the toner, a good image quality that does not generate fireflies and the like can be obtained, and the residual toner can be further reduced. became.

  Titanium oxide fine particles are excellent in environmental stability and image density stability, but have a tendency to deteriorate the charge rise characteristics. Therefore, if the amount of titanium oxide fine particles added is larger than the amount of silica fine particles added, the effect of side effects is large. It is possible to become. However, when the addition amount of the hydrophobic silica fine particles and the hydrophobic titanium oxide fine particles is in the range of 0.3 to 1.5% by mass, the charge rise characteristics are not greatly impaired, and the desired charge rise characteristics can be obtained. It was found that stable image quality can be obtained and toner blowing can be suppressed even when repeated.

The dry toner of the present invention can be produced by the following method, but is not limited thereto.
(Toner production method in aqueous medium)
As the aqueous medium used in the present invention, water alone may be used, but a solvent miscible with water may be used in combination. Examples of the miscible solvent include alcohol (methanol, isopropanol, ethylene glycol, etc.), dimethylformamide, tetrahydrofuran, cellosolves (methyl cellosolve, etc.), lower ketones (acetone, methyl ethyl ketone, etc.), and the like.
As the prepolymer having a functional group containing a nitrogen atom, an NCO group-terminated polyester prepolymer (A) is preferable. As a method for stably forming a dispersion comprising a modified polyester such as urea-modified polyester or a reactive modified polyester such as prepolymer (A) in an aqueous medium, a modified polyester such as urea-modified polyester or a pre-polymer can be used in an aqueous medium. Examples thereof include a method in which a composition of a toner raw material composed of reactive modified polyester such as polymer (A) is added and dispersed by shearing force. Reactive modified polyester such as prepolymer (A) and other toner composition (hereinafter referred to as toner raw material), colorant, colorant masterbatch, release agent, charge control agent, unmodified polyester resin, etc. Although mixing may be performed when forming the dispersion in the medium, it is more preferable to mix the toner raw materials in advance and then add and disperse the mixture in the aqueous medium. In the present invention, other toner materials such as a colorant, a release agent, and a charge control agent do not necessarily have to be mixed when forming particles in an aqueous medium, but after the particles are formed. , May be added. For example, after forming particles containing no colorant, the colorant can be added by a known dyeing method.

  The dispersion method is not particularly limited, and known equipment such as a low-speed shear method, a high-speed shear method, a friction method, a high-pressure jet method, and an ultrasonic wave can be applied. In order to make the particle size of the dispersion 2 to 20 μm, a high-speed shearing type is preferable. When a high-speed shearing disperser is used, the rotational speed is not particularly limited, but is usually 1000 to 30000 rpm, preferably 5000 to 20000 rpm. The dispersion time is not particularly limited, but in the case of a batch method, it is usually 0.1 to 5 minutes. The temperature during dispersion is usually 0 to 150 ° C. (under pressure), preferably 40 to 98 ° C. Higher temperatures are preferred in that the dispersion of the urea-modified polyester or prepolymer (A) has a low viscosity and is easy to disperse.

  The amount of the aqueous medium used is usually 50 to 2000 parts by mass, preferably 100 to 1000 parts by mass with respect to 100 parts of the toner composition containing polyester such as urea-modified polyester and prepolymer (A). If the amount is less than 50 parts by mass, the dispersion state of the toner composition is poor, and toner particles having a predetermined particle size cannot be obtained. If it exceeds 20000 parts by mass, it is not economical. Moreover, a dispersing agent can also be used as needed. It is preferable to use a dispersant because the particle size distribution becomes sharp and the dispersion is stable.

Various dispersants for emulsifying and dispersing the oily phase in which the toner composition is dispersed are used in the liquid containing water. Such a dispersant includes a surfactant, an inorganic fine particle dispersant, a polymer fine particle dispersant and the like.
As surfactants, anionic surfactants such as alkylbenzene sulfonates, α-olefin sulfonates, phosphate esters, alkylamine salts, amino alcohol fatty acid derivatives, polyamine fatty acid derivatives, amine salt types such as imidazoline, Quaternary ammonium salt type cationic surfactants such as alkyltrimethylammonium salt, dialkyldimethylammonium salt, alkyldimethylbenzylammonium salt, pyridinium salt, alkylisoquinolinium salt, benzethonium chloride, fatty acid amide derivative, polyhydric alcohol Nonionic surfactants such as derivatives, for example, amphoteric surfactants such as alanine, dodecyldi (aminoethyl) glycine, di (octylaminoethyl) glycine and N-alkyl-N, N-dimethylammonium betaine. It is.

  Further, by using a surfactant having a fluoroalkyl group, the effect can be obtained in a very small amount. Preferred anionic surfactants having a fluoroalkyl group include fluoroalkyl carboxylic acids having 2 to 10 carbon atoms and metal salts thereof, disodium perfluorooctanesulfonyl glutamate, 3- [omega-fluoroalkyl (C6-C11 ) Oxy] -1-alkyl (C3-C4) sodium sulfonate, 3- [omega-fluoroalkanoyl (C6-C8) -N-ethylamino] -1-propanesulfonic acid sodium, fluoroalkyl (C11-C20) carvone Acids and metal salts, perfluoroalkylcarboxylic acids (C7 to C13) and metal salts thereof, perfluoroalkyl (C4 to C12) sulfonic acids and metal salts thereof, perfluorooctanesulfonic acid diethanolamide, N-propyl-N- ( 2-hydroxyethyl) -Fluorooctanesulfonamide, perfluoroalkyl (C6-C10) sulfonamidopropyltrimethylammonium salt, perfluoroalkyl (C6-C10) -N-ethylsulfonylglycine salt, monoperfluoroalkyl (C6-C16) ethyl phosphate, etc. Is mentioned.

  Product names include Surflon S-111, S-112, S-113 (Asahi Glass Co., Ltd.), Florard FC-93, FC-95, FC-98, FC-129 (Sumitomo 3M Co., Ltd.), Unidyne DS-101. DS-102 (Daikin Kogyo Co., Ltd.), MegaFuck F-110, F-120, F-113, F-191, F-812, F-833 (Dainippon Ink Co., Ltd.), Xtop EF-102 , 103, 104, 105, 112, 123A, 123B, 306A, 501, 201, 204 (manufactured by Tochem Products), and Fgentent F-100, F150 (manufactured by Neos).

  Examples of cationic surfactants include aliphatic primary, secondary or secondary amine acids having a fluoroalkyl group, aliphatic quaternary ammonium salts such as perfluoroalkyl (C6-C10) sulfonamidopropyltrimethylammonium salt, benza Luconium salt, benzethonium chloride, pyridinium salt, imidazolinium salt, trade names include Surflon S-121 (manufactured by Asahi Glass), Florard FC-135 (manufactured by Sumitomo 3M), Unidyne DS-202 (manufactured by Daikin Industries) Megafac F-150, F-824 (manufactured by Dainippon Ink, Inc.), Xtop EF-132 (manufactured by Tochem Products), and Footgent F-300 (manufactured by Neos). In addition, tricalcium phosphate, calcium carbonate, titanium oxide, colloidal silica, hydroxyapatite and the like can be used as an inorganic compound dispersant that is hardly soluble in water.

Further, the same effect as that of the inorganic dispersant was confirmed for the fine particle polymer. For example, MMA polymer fine particles 1 μm and 3 μm, styrene fine particles 0.5 μm and 2 μm, styrene-acrylonitrile fine particle polymer 1 μm, (PB-200H (Kao) SGP (Soken), Technopolymer SB (Sekisui Plastics), SGP-3G (Soken) Micropearl (Sekisui Fine Chemical)).
In addition, as a dispersant that can be used in combination with the above inorganic dispersant and fine particle polymer, the dispersed droplets may be stabilized by a polymer protective colloid. For example, acrylic acid, methacrylic acid, α-cyanoacrylic acid, α-cyanomethacrylic acid, itaconic acid, crotonic acid, fumaric acid, maleic acid or maleic anhydride and other (meth) acrylic monomers containing hydroxyl groups Bodies such as β-hydroxyethyl acrylate, β-hydroxyethyl methacrylate, β-hydroxypropyl acrylate, β-hydroxypropyl methacrylate, γ-hydroxypropyl acrylate, γ-hydroxypropyl methacrylate, 3-acrylate Chloro-2-hydroxypropyl, 3-chloro-2-hydroxypropyl methacrylate, diethylene glycol monoacrylate, diethylene glycol monomethacrylate, glycerol monoacrylate, glycerol monomethacrylate, N -Methylol acrylamide, N-methylol methacrylamide, etc., vinyl alcohol or ethers with vinyl alcohol, such as vinyl methyl ether, vinyl ethyl ether, vinyl propyl ether, etc., or esters of compounds containing vinyl alcohol and carboxyl groups, such as Pinyl acetate, pinyl propionate, vinyl butyrate, acrylamide, methacrylamide, diacetone acrylamide or their methylol compounds, acid chlorides such as acrylic acid chloride, methacrylic acid chloride, pinylviridine, vinylpyrrolidone, vinylimidazole, ethyleneimine, etc. Homopolymers or copolymers such as those having nitrogen atoms or heterocyclic rings thereof, polyoxyethylene, polyoxypropylene, polymers Oxyethylene alkylamine, polyoxypropylene alkylamine, polyoxyethylene alkylamide, polyoxypropylene alkylamide, polyoxyethylene nonyl phenyl ether, polyoxyethylene lauryl phenyl ether, polyoxyethylene stearyl phenyl ester, polyoxyethylene nonylphenyl Polyoxyethylenes such as esters, celluloses such as methyl cellulose, hydroxyethyl cellulose, and hydroxypropyl cellulose can be used.

  Furthermore, in order to reduce the viscosity of the dispersion medium containing the toner composition, a solvent in which a polyester such as urea-modified polyester or prepolymer (A) is soluble can be used. The use of a solvent is preferable in that the particle size distribution becomes sharp. The solvent is preferably volatile with a boiling point of less than 100 ° C. from the viewpoint of easy removal. Examples of the solvent include toluene, xylene, benzene, carbon tetrachloride, methylene chloride, 1,2-dichloroethane, 1,1,2-trichloroethane, trichloroethylene, chloroform, monochlorobenzene, dichloroethylidene, methyl acetate, ethyl acetate, Methyl ethyl ketone, methyl isobutyl ketone and the like can be used alone or in combination of two or more. In particular, aromatic solvents such as toluene and xylene and halogenated hydrocarbons such as methylene chloride, 1,2-dichloroethane, chloroform, and carbon tetrachloride are preferable. The usage-amount of the solvent with respect to 100 parts of prepolymers (A) is 0-300 parts normally, Preferably it is 0-100 parts, More preferably, it is 25-70 parts. When a solvent is used, the solvent (solvent) is removed from the resultant reaction product under normal pressure or reduced pressure after the extension and / or crosslinking reaction of the modified polyester (prepolymer) with an amine.

  The elongation and / or cross-linking reaction time is selected, for example, depending on the reactivity depending on the combination of the isocyanate group structure of the prepolymer and amines, and is usually 10 minutes to 40 hours, preferably 2 to 24 hours. The reaction temperature is generally 0 to 150 ° C, preferably 40 to 98 ° C. Moreover, a well-known catalyst can be used as needed. Specific examples include dibutyltin laurate and dioctyltin laurate. In addition, as an extender and / or a crosslinking agent, the above-described amines (B) are used.

  In the present invention, it is preferable to remove the solvent of the dispersion at 10 to 50 ° C. prior to the removal of the solvent from the dispersion (reaction liquid) after the elongation and / or crosslinking reaction. The toner is deformed by liquid agitation before the removal of the solvent. On the other hand, the ratio Dv / Dn of the volume average particle diameter Dv and the number average diameter (Dn) of the toner is mainly determined by adjusting, for example, the water phase viscosity, the oil phase viscosity, the characteristics of the resin fine particles, and the addition amount. Can be controlled. It also varies depending on the WAX dispersion particle size. Dv and Dn can be controlled, for example, by adjusting the characteristics, addition amount, etc. of the resin fine particles.

The toner of the present invention can be used as a two-component developer. In this case, it may be used by mixing with a magnetic carrier, and the content ratio of the carrier and the toner in the developer is preferably 1 to 10 parts by mass of the toner with respect to 100 parts by mass of the carrier. As the magnetic carrier, conventionally known ones such as iron powder, ferrite powder, magnetite powder, magnetic resin carrier having a particle diameter of about 20 to 200 μm can be used. Examples of the coating material include amino resins such as urea-formaldehyde resin, melamine resin, benzoguanamine resin, urea resin, polyamide resin, and epoxy resin. Polyvinyl and polyvinylidene resins such as acrylic resins, polymethyl methacrylate resins, polyacrylonitrile resins, polyvinyl acetate resins, polyvinyl alcohol resins, polyvinyl butyral resins, polystyrene resins and styrene acrylic copolymer resins, Halogenated olefin resin such as vinyl, polyester resin such as polyethylene terephthalate resin and polybutylene terephthalate resin, polycarbonate resin, polyethylene resin, polyvinyl fluoride resin, polyvinylidene fluoride resin, polytrifluoroethylene resin, polyhexafluoro Propylene resin, copolymer of vinylidene fluoride and acrylic monomer, copolymer of vinylidene fluoride and vinyl fluoride, tetrafluoroethylene and vinylidene fluoride And fluoro such as terpolymers of non-fluoride monomers including, and silicone resins. Moreover, you may make conductive powder etc. contain in coating resin as needed. As the conductive powder, metal powder, carbon black, titanium oxide, tin oxide, zinc oxide or the like can be used. These conductive powders preferably have an average particle diameter of 1 μm or less. When the average particle diameter is larger than 1 μm, it becomes difficult to control electric resistance.
The toner of the present invention can also be used as a one-component magnetic toner that does not use a carrier or a non-magnetic toner.

  A mode for carrying out the image forming method of the present invention will be described with reference to FIGS. The tandem image forming apparatus shown in FIG. 1 is a tandem type color image forming apparatus. The tandem image forming apparatus includes a copying apparatus main body 150, a paper feed table 200, a scanner 300, and an automatic document feeder (ADF) 400.

  The copying machine main body 150 is provided with an endless belt-shaped intermediate transfer member 1050 at the center. The intermediate transfer member 1050 is stretched around support rollers 1014, 1015, and 1016, and can rotate clockwise in FIG. An intermediate transfer body cleaning device 1017 for removing residual toner on the intermediate transfer body 1050 is disposed in the vicinity of the support roller 1015. The intermediate transfer member 1050 stretched by the support roller 1014 and the support roller 1015 has a tandem type in which four image forming units 1018 of yellow, cyan, magenta, and black are arranged to face each other along the conveyance direction. A developing device 120 is disposed. An exposure device 1021 is disposed in the vicinity of the tandem developing device 120. A secondary transfer device 1022 is disposed on the side of the intermediate transfer body 1050 opposite to the side on which the tandem developing device 120 is disposed. In the secondary transfer device 1022, a secondary transfer belt 1024, which is an endless belt, is stretched around a pair of rollers 1023, and the transfer sheet conveyed on the secondary transfer belt 1024 and the intermediate transfer body 1050 are in contact with each other. Is possible. A fixing device 1025 is disposed in the vicinity of the secondary transfer device 1022. The fixing device 1025 includes a fixing belt 1026 that is an endless belt, and a pressure roller 1027 that is pressed against the fixing belt 1026.

  In the tandem image forming apparatus, a sheet reversing device 1028 for reversing the transfer paper for image formation on both sides of the transfer paper is disposed in the vicinity of the secondary transfer device 1022 and the fixing device 1025. .

  Next, formation of a full-color image (color copy) using the tandem developing device 120 will be described. That is, first, a document is set on the document table 130 of the automatic document feeder (ADF) 400, or the automatic document feeder 400 is opened and a document is set on the contact glass 1032 of the scanner 300. 400 is closed.

  When a start switch (not shown) is pressed, when a document is set on the automatic document feeder 400, the document is transported and moved onto the contact glass 1032 and then the document is set on the contact glass 1032. Immediately after that, the scanner 300 is driven, and the first traveling body 1033 and the second traveling body 1034 travel. At this time, the light from the light source is emitted from the first traveling body 1033 and the reflected light from the document surface is reflected by the mirror in the second traveling body 1034 and is received by the reading sensor 1036 through the imaging lens 1035 to be color. An original (color image) is read and used as black, yellow, magenta, and cyan image information.

  Each image information of black, yellow, magenta, and cyan is stored in each image forming unit 1018 (black image forming unit, yellow image forming unit, magenta image forming unit, cyan image) in the tandem developing unit 120. Each of the image forming units forms black, yellow, magenta, and cyan toner images. That is, each image forming means 1018 (black image forming means, yellow image forming means, magenta image forming means, and cyan image forming means) in the tandem developing means 120 is a static image as shown in FIG. An electrostatic latent image carrier 1110 (an electrostatic latent image carrier for black 1010K, an electrostatic latent image carrier for yellow 1010Y, an electrostatic latent image carrier for magenta 1010M, and an electrostatic latent image carrier for cyan 1010C); The electrostatic latent image carrier 1110 is uniformly charged, and the electrostatic latent image carrier is exposed for each color image-corresponding image based on each color image information (L in FIG. 2). An exposure apparatus for forming an electrostatic latent image corresponding to each color image on the electrostatic latent image carrier, and the electrostatic latent image for each color toner (black toner, yellow toner, magenta toner, and the like). A developing device 61 that develops the toner image using each color toner by developing with a cyan toner, a transfer charger 1062 for transferring the toner image onto the intermediate transfer body 1050, a cleaning device 63, and a static eliminator. 64, each monochrome image (black image, yellow image, magenta image, and cyan image) can be formed based on the image information of each color. The black image, the yellow image, the magenta image, and the cyan image formed in this way are respectively transferred to an electrostatic latent image carrier 1010K for black on an intermediate transfer member 1050 that is rotated by support rollers 1014, 1015, and 1016. The black image formed above, the yellow image formed on the yellow electrostatic latent image carrier 1010Y, the magenta image formed on the magenta electrostatic latent image carrier 1010M, and the electrostatic latent image carrier for cyan The cyan image formed on 1010C is sequentially transferred (primary transfer). Then, the black image, the yellow image, the magenta image, and the cyan image are superimposed on the intermediate transfer member 1050 to form a composite color image (color transfer image).

  On the other hand, in the paper feed table 200, one of the paper feed rollers 142 is selectively rotated to feed out a sheet (recording paper) from one of the paper feed cassettes 144 provided in multiple stages in the paper bank 143. The sheets are separated one by one and sent to the sheet feeding path 146, conveyed by the conveying roller 147, guided to the sheet feeding path 148 in the copying machine main body 150, and abutted against the registration roller 1049 to stop. Alternatively, the sheet feeding roller 142 is rotated to feed out the sheets (recording paper) on the manual feed tray 1054, separated one by one by the separation roller 1058, put into the manual feed path 1053, and abutted against the registration roller 1049 and stopped. . The registration roller 1049 is generally used while being grounded, but may be used in a state where a bias is applied to remove paper dust from the sheet. Then, the registration roller 1049 is rotated in synchronization with the synthesized color image (color transfer image) synthesized on the intermediate transfer member 1050, and a sheet (recording paper) is interposed between the intermediate transfer member 1050 and the secondary transfer device 1022. And transferring the composite color image (color transfer image) onto the sheet (recording paper) by the secondary transfer device 1022, thereby transferring the color image onto the sheet (recording paper). Is formed. The residual toner on the intermediate transfer member 1050 after the image transfer is cleaned by the intermediate transfer member cleaning device 1017.

  The sheet (recording paper) on which the color image has been transferred is conveyed by the secondary transfer device 1022 and sent to the fixing device 1025, where the combined color image (color) is generated by heat and pressure. (Transfer image) is fixed on the sheet (recording paper). Thereafter, the sheet (recording paper) is switched by the switching claw 1055 and discharged by the discharge roller 1056 and stacked on the paper discharge tray 1057 or switched by the switching claw 1055 and reversed by the sheet reversing device 1028 and transferred again. After being guided to the position and recording an image on the back side, it is discharged by the discharge roller 1056 and stacked on the discharge tray 1057.

Hereinafter, the present invention will be further described with reference to examples, but the present invention is not limited thereto. Hereinafter, a part shows a mass part.
Example 1
(Example of polyester production)
In a reaction vessel equipped with a cooling tube, a stirrer, and a nitrogen introduction tube, 690 parts of bisphenol A ethylene oxide 2-mole adduct and 256 parts of terephthalic acid were subjected to polycondensation at 230 ° C. for 8 hours under normal pressure, and then reduced in pressure to 10 to 15 mmHg. And then cooled to 160 ° C., 18 parts of phthalic anhydride was added thereto and reacted for 2 hours to obtain unmodified polyester (1). The obtained polyester (1) had a weight average molecular weight of 4,000, an acid value of 10 KOH mg / g, and a glass transition point of 50 ° C.

(Prepolymer Production Example) 463 parts of propylene glycol, 657 parts of terephthalic acid, 96 parts of trimellitic anhydride, and 2 parts of titanium tetrabutoxide are charged into a reaction vessel equipped with a cooling tube, a stirrer, and a nitrogen introduction tube. An intermediate was obtained by reacting at 8 ° C. (normal pressure) for 8 hours and further reacting at 10 to 15 mmHg for 5 hours. The intermediate had a weight average molecular weight of 28000, a glass transition temperature of 36 ° C., an acid value of 0.6 mgKOH / g, and a hydroxyl value of 16.5 mgKOH / g.
[Prepolymer 1] was prepared by charging 250 parts of an intermediate, 18 parts of isophorone diisocyanate and 250 parts of ethyl acetate in a reaction vessel equipped with a cooling pipe, a stirrer and a nitrogen introduction pipe and reacting at 100 ° C. for 5 hours. Obtained. The content of isocyanate group in [Prepolymer 1] was 0.61%.

(Production Example of Wax Dispersion-1)
70 parts of ethyl acetate, 25 parts of the above polyester (1), 5 parts of paraffin wax (melting point: 68 ° C.): 5 parts, and 3% zirconia with a volume ratio of 60% were added. The mixture was stirred for 24 hours with Model 5400 (manufactured by REDDEVIL, USA) to obtain Wax Dispersion-1. When the volume average particle size (Dv) of the wax dispersion particles contained in the obtained wax dispersion was measured with a particle size distribution measuring device (“LA-920”; manufactured by Horiba, Ltd.) using a laser light scattering method, It was 0.21 μm.

(Preparation of organic resin fine particle dispersion)
In a reaction vessel in which a stir bar and a thermometer are set, 683 parts by mass of water, 20 parts by mass of a sodium salt of ethylene oxide methacrylate adduct sulfate ("Eleminol RS-30" manufactured by Sanyo Chemical Industries), 78 parts by mass of styrene , 78 parts by mass of methacrylic acid, 120 parts by mass of butyl acrylate, and 1 part by mass of ammonium persulfate were added and stirred at 400 rpm for 15 minutes to obtain a white emulsion. The emulsion was heated to raise the system temperature to 75 ° C. and reacted for 5 hours. Next, 30 parts by mass of a 1% by mass ammonium persulfate aqueous solution was added, and the mixture was aged at 75 ° C. for 5 hours. Vinyl resin particles (styrene-methacrylic acid-butyl acrylate-methacrylic acid ethylene oxide adduct sulfate sodium salt) (Copolymer) aqueous dispersion (fine particle dispersion 1) was prepared. The volume average particle diameter (Dv) of the organic resin fine particles contained in the obtained organic resin fine particle dispersion was measured by a particle size distribution measuring device (“nanotrac UPA-150EX”; manufactured by Nikkiso Co., Ltd.), and found to be 55 nm. .

(Adjustment of aqueous phase)
Water: 990 parts, [fine particle dispersion 1]: 83 parts, 48.5% aqueous solution of sodium dodecyl diphenyl ether disulfonate (Eleminol MON-7: Sanyo Chemical Industries): 37 parts, ethyl acetate: 90 parts The mixture was stirred to obtain a milky white liquid. This is designated as [Aqueous Phase 1].

(Synthesis of Pigment MB)
In a reaction vessel equipped with a condenser, a stirrer and a nitrogen introduction tube, 319 parts of bisphenol A propylene oxide 2-mole adduct: 449 parts, 449 parts of bisphenol A ethylene oxide 2-mole adduct, 243 parts of terephthalic acid, adipic acid: 53 parts and dibutyltin oxide: 2 parts were added, reacted at 230 ° C. at normal pressure for 8 hours, further reacted at 5 to 15 mm Hg under reduced pressure, and then put 7 parts of trimellitic anhydride into the reaction vessel, The reaction was carried out at 180 ° C. and normal pressure for 2 hours to obtain [Polyester 1 for MB]. [Polyester 1 for MB] had a number average molecular weight of 1900, a mass average molecular weight of 6100, Tg of 43 ° C., and an acid value of 1.1. 1200 parts of water, 540 parts of carbon black Printex 35 (manufactured by Dexa) having a DBP oil absorption of 42 ml / 100 mg and a pH of 9.5 and 1200 parts of [polyester resin for MB], a Henschel mixer (manufactured by Mitsui Mining) Used and mixed. Next, the obtained mixture was kneaded at 150 ° C. for 30 minutes using two rolls, then rolled and cooled, and pulverized with a pulverizer to obtain [Masterbatch 1].

(Synthesis of inorganic mineral MB)
Water: 30 parts, Kraton APA (manufactured by Southern Clay Products): 40 parts, [Polyester 1 for MB]: 60 parts are added and mixed with a Henschel mixer (manufactured by Mitsui Mining Co., Ltd.), and water soaks into the inorganic mineral aggregate. Got a mixture. The mixture was kneaded at 130 ° C. for 45 minutes using two rolls, rolled and cooled, and pulverized with a pulverizer to obtain [Masterbatch 2].

(Preparation of oil phase-1)
In a container equipped with a stirring bar and a thermometer, 65 parts of 65% ethyl acetate solution of [Polyester 1], 50 parts of wax dispersion-1: 20 parts of 50% ethyl acetate solution of [Masterbatch 1], [ Masterbatch 2] 0.55 part was charged, heated to 80 ° C. with stirring, held at 80 ° C. for 5 hours, and then cooled to 30 ° C. in 1 hour to obtain [Pigment / Wax Dispersion 1]. .

Example 1
(Emulsification → Desolvation) 749 parts of [Pigment / Wax Dispersion 1], 111 parts of [Prepolymer 1], 1.3 parts of Isophoronediamine and 3 parts of glacial acetic acid are placed in a container, and TK Homomixer (manufactured by Tokushu Kika) ) Was added for 1 minute at 5000 rpm, 1200 parts of an aqueous medium was added to the container, and the mixture was mixed for 20 minutes at 13000 rpm using a TK homomixer to obtain an emulsified slurry. The emulsified slurry was put into a container equipped with a stirrer and a thermometer, and after removing the solvent at 30 ° C. for 8 hours, aging was carried out at 45 ° C. for 6 hours to obtain a dispersed slurry.
After filtering 100 parts of the dispersion slurry under reduced pressure, 100 parts of ion-exchanged water was added to the filter cake 1 and mixed at 12000 rpm for 10 minutes using a TK homomixer, followed by filtration. Next, 100 parts of distilled water was added to the obtained filter cake 2, mixed at 12000 rpm for 30 minutes using a TK homomixer, and then filtered under reduced pressure. Next, 100 parts of 10% hydrochloric acid was added to the obtained filter cake 3, mixed at 12000 rpm for 10 minutes using a TK homomixer, and then filtered. Furthermore, 300 parts of ion-exchanged water was added to the obtained filter cake 4, and after mixing for 10 minutes at 12000 rpm using a TK homomixer, the filter cake 5 was obtained by performing the operation of filtering twice. The filter cake 5 was dried at 45 ° C. for 48 hours using a circulating dryer, and sieved with a mesh having an opening of 75 μm. The resulting toner base particles: 100 parts of hydrophobic silica (hexamethyldisilazane surface) Treated product, specific surface area: 200 m ^{2 /} g): 0.5 part and hydrophobized rutile type titanium oxide (isobutyltrimethoxysilane surface treated product, average primary particle size: 0.02 μm): 0.5 part Henschel mixer To obtain toner (1).

Example 2
Toner (2) was obtained in the same manner as in Example 1 except that 3 parts of glacial acetic acid during emulsification was changed to 3.5 parts.
Example 3
A toner (3) was obtained in the same manner as in Example 1 except that 3 parts of glacial acetic acid during emulsification was changed to 4 parts.
Example 4
A toner (4) was obtained in the same manner as in Example 1 except that 3 parts of glacial acetic acid during emulsification was changed to 2.5 parts.
Example 5
A toner (5) was obtained in the same manner as in Example 1 except that 3 parts of glacial acetic acid during emulsification was changed to 4.5 parts.

(Preparation of oil phase-2)
In a container equipped with a stir bar and a thermometer, 65 parts of 65% ethyl acetate solution of [polyester 1], 50 parts of wax dispersion-1 and 20 parts of 50% ethyl acetate solution of [masterbatch 1] were added. The resulting mixture was heated to 80 ° C. with stirring and kept at 80 ° C. for 5 hours, and then cooled to 30 ° C. over 1 hour to obtain [Pigment / Wax Dispersion 2].

Comparative Example 1
Toner (6) was obtained in the same manner as in Example 1 except that [Pigment / Wax Dispersion 1] was changed to [Pigment / Wax Dispersion 2] during emulsification.
Comparative Example 2

(Glass transition point Tg (℃))
The glass transition point is measured with a Rigaku THRMOFLEX TG8110 manufactured by Rigaku Corporation at a temperature increase rate of 10 ° C./min.
A method for measuring Tg will be outlined. As an apparatus for measuring Tg, a TG-DSC system TAS-100 manufactured by Rigaku Corporation was used.
First, about 10 mg of a sample is placed in an aluminum sample container, which is placed on a holder unit and set in an electric furnace. First, after heating from room temperature to 150 ° C. at a temperature rising rate of 10 ° C./min, the sample was allowed to stand at 150 ° C. for 10 minutes, the sample was cooled to room temperature and left for 10 minutes, and the temperature rising rate was again increased to 150 ° C. under a nitrogen atmosphere. DSC measurement was performed by heating at min. Tg was calculated from the tangent of the endothermic curve near the Tg and the base line using the analysis system in the TAS-100 system.

(Image graininess, sharpness)
Using a digital full-color copying machine (imageColor 2800, manufactured by Ricoh), a photographic image was output in a single color, and the degree of graininess and sharpness was visually evaluated. In order from the best, “◎” is equivalent to offset printing, “○” is slightly worse than offset printing, “△” is much worse than offset printing, “×” is about the same as conventional electrophotographic images (very much Bad).

(Dirt)
Using a digital full-color copying machine (imageColor 2800, manufactured by Ricoh), after running 30000 image charts with 50% image area in single color mode, the blank image is stopped during development, and the developer on the photoconductor after development is removed. The tape was transferred, and the difference from the image density of the untransferred tape was measured with a 938 spectrodensitometer (manufactured by X-Rite). The smaller the difference in image density, the better the background stain, and the better ones were ranked in the order of “◎”, “◯”, “Δ”, “×”.

(Fixability evaluation)
Ricoh Copier Co., Ltd. using a Teflon (registered trademark) roller as a fixing roller MF2200 A machine having a modified fixing unit was set with Ricoh type 6200 paper and subjected to a copying test. The cold offset temperature (fixing lower limit temperature) and the hot offset temperature (hot offset resistant temperature) were determined by changing the fixing temperature. The minimum fixing temperature of the conventional low-temperature fixing toner is about 140 to 150 ° C. The evaluation conditions were set such that the paper feed linear velocity was 120 to 150 mm / sec, the surface pressure was 1.2 kgf / cm ² , and the nip width was 4.5 mm. The criteria for each characteristic evaluation are as follows.

The properties and evaluation results of the toners produced in each example and comparative example are shown in the table.

FIG. 2 is a cross-sectional configuration diagram of a main part of an example of an image forming apparatus. FIG. 2 is a partially enlarged view of the image forming apparatus illustrated in FIG. 1.

Explanation of symbols

1010K electrostatic latent image carrier for black 1010Y electrostatic latent image carrier for yellow 1010M electrostatic latent image carrier for magenta 1010C electrostatic latent image carrier for cyan 1014 support roller 1015 support roller 1016 support roller 1017 intermediate transfer cleaning device DESCRIPTION OF SYMBOLS 1018 Image formation means 1021 Exposure apparatus 1022 Secondary transfer apparatus 1023 Roller 1024 Secondary transfer belt 1025 Fixing apparatus 1026 Fixing belt 1027 Pressure roller 1028 Sheet reversing apparatus 1032 Contact glass 1033 First traveling body 1034 Second traveling body 1035 Imaging lens 1036 Reading sensor 1049 Registration roller 1050 Intermediate transfer member 1053 Manual feed path 1054 Manual feed tray 1055 Switching claw 1056 Ejection roller 1057 Ejection tray 1058 Separation Roller 61 Developing device 1062 Transfer charger 63 Cleaning device 64 Static eliminator 120 Tandem developing device 130 Document table 142 Paper feed roller 143 Paper bank 144 Paper feed cassette 145 Separating roller 146 Paper feed route 147 Transport roller 148 Paper feed route 150 Copying Main body 160 Charging device 200 Paper feed table 300 Scanner 400 Automatic document feeder (ADF)

Claims (12)

In a toner containing at least a release agent,
(1) The release agent is a hydrocarbon wax having a melting point of 60 to 90 ° C.
(2) The endothermic peak of the endothermic peak derived from the release agent in the DSC measurement of the toner is in the range of 3.5 to 5.5 J / g,
(3) The average circularity of the toner is 0.94 or more, and the ratio (D / S) of the ground contact area (D) to the total projected area (S) of the toner is 15 to 40%,
(4) An image forming toner, wherein a charge control agent is fixed on the surface of the toner particles.   The image forming toner according to claim 1, wherein the ground contact area (D) is a total area of a contact surface of the toner with a target surface. When the toner is placed on a horizontal glass flat plate by dropping the toner from a position 10 cm above the glass flat plate with a mesh of 22 μm and sieving for 10 seconds, the toner and the glass flat surface are placed. The toner for image formation according to claim 1 or 2, defined as a total area of a contact surface with the face plate. The ratio (L / M) of the major axis L to the minor axis M of the contact portion satisfies the relationship of (L / M)> 2 in at least one of the portions where the toner is in contact with the glass flat plate. Item 4. The image forming toner according to any one of Items 1 to 3.   At least a polyester prepolymer having a functional group containing a nitrogen atom, a polyester, a colorant, a release agent, and a toner material liquid in which an inorganic filler is dispersed in an organic solvent are crosslinked and / or extended in an aqueous medium. An image forming toner obtained by the method, wherein the shape factor SF-1 of the toner is in the range of 130 to 160, and the shape factor SF-2 is in the range of 110 to 140. The image forming toner according to claim 1. The toner has a volume average particle diameter (Dv) of 3 to 8 μm and a ratio (Dv / Dn) of the volume average particle diameter (Dv) to the number average particle diameter (Dn) in the range of 1.00 to 1.30. The image forming toner according to claim 1, wherein the toner is for image formation. The toner according to any one of claims 1 to 6, wherein the inorganic filler is montmorillonite or a modified product thereof.   The image forming toner according to claim 1, wherein the toner is a toner obtained by externally adding fine particles having an average primary particle size of 50 to 500 nm to the surface of the toner base particles. .   The toner for image formation according to claim 1, wherein the toner has a glass transition point of 40 to 60 ° C. The image forming toner according to claim 1, wherein 1 to 10% by number of particles of 2 μm or less of the toner is used.   An image forming method using the toner according to claim 1.   An image forming apparatus using the toner according to claim 1 as an electrostatic charge image forming unit.

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