JP2007155858A - Electrostatic image developer and image forming method using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance the image density and image reproducibility of an image obtained by using an electrostatic image developer including a toner and carrier manufactured by a wet process, and to prevent occurrence of image defects such as fog. <P>SOLUTION: A toner for electrostatic image development, which is obtained by a manufacturing method including a raw material mixing step S1, an aggregate forming step S2, a particle forming step S3 and a washing step S4, and comprises a pigment and a self-dispersive resin comprising a self-dispersive polyester, is used as the toner manufactured by the wet process. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electrostatic charge image developer and an image forming method using the same.

  With the recent remarkable development of OA equipment, copying machines, printers, facsimile machines, and the like that perform image formation using an electrophotographic method have become widespread. In general, an image forming apparatus using an electrophotographic system forms an image by a charging process, an exposure process, a development process, a transfer process, a cleaning process, and a fixing process. In the charging step, the surface of the photoconductor as an image forming body is uniformly charged in a dark place. In the exposure process, the signal light of the original image is projected onto the charged photoconductor, and the charged portion is removed from the exposed portion to form an electrostatic charge image (electrostatic latent image) on the surface of the photoconductor. In the development step, an electrostatic image developing toner (hereinafter simply referred to as “toner” unless otherwise specified) is supplied to the electrostatic image on the surface of the photoreceptor to form a toner image (visible image). In the transfer process, a recording medium such as paper or sheet is brought into contact with the toner image on the surface of the photoreceptor, and corona discharge is performed from the side opposite to the surface of the recording medium in contact with the toner image to record charges having a polarity opposite to that of the toner. By giving to the medium, the toner image is transferred to the recording medium. In the fixing step, the toner image on the recording medium is fixed by means such as heating and pressing. In the cleaning process, the toner remaining on the surface of the photoreceptor without being transferred to the recording medium is collected. An image forming apparatus using an electrophotographic system forms a desired image on a recording medium through the above steps.

  In an image forming apparatus using an electrophotographic system, as a developer for developing a toner image, a one-component developer containing only toner and a two-component developer containing toner and carrier are used. Compared to a one-component developer containing toner particles alone, the toner particles are agitated, transported and charged by the carrier, so that the toner particles do not need to have a carrier function and the functions are separated. Controllability is improved, and high-quality images can be easily obtained. For this reason, active research has been conducted on methods for producing toners suitable for use in combination with carriers.

  Conventionally, a dry method and a wet method are known as toner production methods. Among the dry methods, a pulverization method in which toner components such as synthetic resins (binder resins), pigments (colorants), waxes, charge control agents, etc. are melt-kneaded and the resulting kneaded material is pulverized and classified is widely used industrially. Has been. On the other hand, with the recent remarkable development of image display devices such as liquid crystal panels, it is required to print high-definition high-quality images displayed on the image display device with good reproducibility. In other words, the reduction in the toner particle diameter is one of the problems for forming a high-quality image. If the particle size of the toner is reduced by a general pulverization method, the energy and time required for the pulverization increase, the manufacturing process becomes complicated, and the product yield decreases, resulting in a significant increase in manufacturing cost. There's a problem. Accordingly, attention has been focused on a wet method in which the production of a small particle size toner is relatively easy.

As the wet method, for example, 1) a suspension polymerization method in which a synthetic resin monomer such as a vinyl monomer is polymerized in an aqueous medium containing a pigment (for example, see Patent Documents 1 to 3), 2) water of synthetic resin particles An emulsion polymerization method in which the dispersion liquid and the dispersion liquid of the pigment in an organic solvent are mixed to form aggregated particles of the synthetic resin particles and the pigment, and the aggregated particles are heated and melted (for example, see Patent Documents 4 to 6). 3) Dissolve or disperse a self-water dispersible resin and pigment in an organic solvent, add a neutralizing agent that neutralizes the dissociation group of the resin, and add water with stirring, so that the pigment is included. Formed resin solution droplets, and phase-inversion emulsification method for obtaining toner particles by phase inversion emulsification of the resin solution droplets (see, for example, Patent Document 7) 4) Resin is added to an aqueous medium containing an inorganic dispersant. After adding organic solvent solution and granulating toner particles A method of obtaining toner particles while removing the solvent and drying, and adjusting the particle size of the inorganic dispersant and changing the resin type as necessary (see, for example, Patent Documents 8 to 11), 5) When washing toner particles obtained in the same manner as in the method 4), the toner particles are repeatedly washed until the difference between the electric conductivity of water before washing and that after washing becomes 200 μS / cm (for example, Patent Documents) 12), 6) In the method of 4) above, a method of adding a surfactant together with an organic solvent solution of a resin in an aqueous medium (for example, see Patent Document 13), 7) In the method of 4) above, average particles Examples thereof include a method in which an inorganic dispersant having a diameter of 0.1 to 2 μm is used, and a surfactant is added together with an organic solvent solution of a resin in an aqueous medium (for example, see Patent Document 14).

  Toners obtained by these wet methods contain residues such as organic solvents and monomers, and these residues disperse the chargeability of the toner and ooze out on the surface of the toner during electrostatic charge image development. Damage the member. Therefore, although a drying process for removing the organic solvent, monomer, etc. from the toner is required, subtle fluctuations in drying conditions such as pressure, temperature, time, etc. cause variations in toner shape, chargeability, etc. There are many cases. For this reason, it is necessary to optimize and maintain the drying conditions, but it is very difficult to achieve it in industrial scale production. In addition, since a facility for treating waste liquid generated by using a large amount of an organic solvent, a monomer, or the like that imposes a heavy load on the natural environment is required, the toner manufacturing cost further increases. In addition, in the method 2), since it is difficult to add a charge control agent, there is a disadvantage that a toner having desired charging characteristics cannot be obtained.

  Further, the toner obtained by the conventional wet method as described above has the image density, image reproducibility (particularly color reproducibility) of the image formed on the recording medium, and pigment dispersibility on the recording medium. Further improvements are desired in terms of the transfer rate to the recording medium, and it is also desired to further reduce the occurrence of image defects such as fogging.

  Therefore, a wet method has been proposed that utilizes the dispersibility of a self-dispersing resin in water and does not use an organic solvent and does not perform a polymerization reaction.

  For example, a pigment aqueous dispersion containing sodium sulfonated polyester as a pigment dispersant and a pigment is added to the emulsion containing sodium sulfonated polyester particles as a self-dispersing resin while applying a shearing force. An example is a method in which an alkali halide is added and the resulting mixture is aggregated by heating to obtain toner particles (for example, see Patent Document 15). The toner obtained by this method does not reach a satisfactory level in terms of color reproducibility and the like because the dispersibility of the pigment in water by the sodium sulfonated polyester is insufficient and aggregates of the pigment are formed. . There is also a problem that charging performance varies depending on environmental conditions such as humidity and temperature. This is considered to be due to the influence of the sulfonic acid group which is a hydrophilic group contained in the sodium sulfonated polyester.

  Also, an aqueous dispersion of self-dispersing resin particles containing a hydrophilic ethylenically unsaturated monomer and a pigment aqueous dispersion are mixed, and a polyvalent metal salt is added to this mixture to add the self-dispersing solution into the mixture. And a method in which toner particles are obtained by forming aggregated particles of water-soluble resin particles and pigment and then heating the mixture to a temperature equal to or higher than the glass transition point of the self-dispersing resin to fuse the aggregated particles ( For example, see Patent Document 16). And in paragraph [0029] of Patent Document 16, styrene sulfonic acid and its metal salt, acrylic acid, methacrylic acid, maleic acid, itaconic acid and the like are exemplified as hydrophilic ethylenically unsaturated monomers. In the Examples, only sodium styrene sulfonate is specifically effective. Therefore, the toner of Patent Document 16 produced using a self-dispersing resin having a sulfonic acid group has a problem that the charging performance varies depending on environmental conditions, like the toner of Patent Document 15.

Also, an aqueous dispersion of a vinyl resin, an aqueous dispersion of a self-dispersing polyester, and an aqueous dispersion of a toner component other than a binder resin such as a pigment are mixed, and the mixture is mixed with an ionic surfactant that is an aggregating agent. A method of obtaining an agglomerate as toner particles by adding an agent and heating (Patent Document 17). In Patent Document 17, as described in claim 2, an aqueous dispersion of a self-dispersing polyester obtained by distilling off an organic solvent from a mixture containing a neutralizing substance such as polyester, acid or base, an organic solvent and water. Is used. Such self-dispersing polyesters have insufficient dispersibility in water, and thus the size of the toner particles obtained may vary. Further, only an ionic surfactant is used as the flocculant, and no polyvalent metal salt is described. Although the ionic surfactant aggregates the toner component, the cohesive force thereof is weak, and only a soft aggregate in which the toner component is not firmly bonded is obtained. As a result, it becomes difficult to control the particle diameter of the toner particles. In addition, paragraphs [0011] to [0012] describe a carboxylic acid compound that is a raw material for polyester, and examples include trivalent or higher carboxylic acids, but trivalent or higher carboxylic acids are used as much as possible. It is described that it is preferable not to.

JP 57-154253 A JP 59-62870 JP-A-57-181553 JP-A 63-186253 JP-A 63-282758 JP-A-63-282749 JP-A-5-66600 JP-A-7-152202 JP-A-7-168395 JP-A-7-168396 JP 7-219267 A JP-A-8-179555 JP-A-8-179556 Japanese Patent Laid-Open No. 9-230624 JP-A-10-39545 JP 2002-131977 A JP 2004-354411 A

  An object of the present invention is a toner manufactured by a wet process, and the particle size and charging performance are almost uniform, and the charging performance is stable even when the environmental conditions are changed, and the pigment dispersibility on the recording medium is improved. An electrostatic charge image developer that can form a high-definition, high-quality image that includes a toner having an improved transfer rate to the toner, has good image density and image reproducibility, and has very few image defects such as fog, and the like. An image forming method using an image developer is provided.

The present invention
Containing a pigment and a self-dispersing resin containing a self-dispersing polyester;
Self-dispersing polyester
A polycondensate of a polycarboxylic acid containing three or more carboxyl groups in one molecule and a carboxylic acid compound containing one or more selected from acid anhydrides thereof and an alcohol compound containing a polyhydric alcohol. An electrostatic charge image developer comprising a toner for developing electrostatic charge and a carrier coated with a silicone resin containing an aminosilane coupling agent.

  The electrostatic charge image developer of the present invention is a coating silicone containing a silicone resin and an amino group-containing silane coupling agent on the surface of a core material having a volume average particle size of 25 to 150 μm (25 μm or more and 150 μm or less). A coating layer made of a resin composition is formed.

Furthermore, the electrostatic charge image developer of the present invention is characterized in that the core material is ferrite particles.
Furthermore, the electrostatic charge image developer of the present invention has an average particle diameter ratio of carrier to electrostatic charge developing toner (average particle diameter of carrier / average particle diameter of electrostatic charge image developing toner) of 5 or more, and The mixing ratio represented by the total projected area of the electrostatic charge developing toner with respect to the total surface area of the carrier is 30 to 70% (30% or more and 70% or less).

  Furthermore, the electrostatic charge image developer of the present invention is characterized in that the coating silicone resin composition contains 10 parts by weight or less of an amino group-containing silane coupling agent with respect to 100 parts by weight of the crosslinkable silicone resin.

The present invention also provides
Vibration formed by the developer carrying carrier transporting the developer to a developing region formed in the vicinity of the developer carrying carrier and the image forming body, and applying an AC bias voltage to the developer carrying carrier. A multicolor toner image is formed by repeatedly performing a developing process in which an electrostatic charge image on an image forming body is visualized by a reversal developing method under an electric field, and superimposing a plurality of toner images having different colors on the image forming body. In the multicolor image forming method,
A multicolor image forming method using any one of the above-described electrostatic charge image developers as a developer.

  According to the present invention, a carboxylic acid containing a polyvalent carboxylic acid containing a pigment and a self-dispersing resin containing a self-dispersing polyester as a main component, the self-dispersing polyester having three or more carboxyl groups in one molecule. Formed on the surface a coating layer comprising a toner for electrostatic charge development, which is a polycondensate of an acid compound and an alcohol compound containing a polyhydric alcohol, and a silicone resin composition for coating containing a silicone resin and an amino group-containing silane coupling agent An electrostatic charge image developer is provided. The electrostatic charge developing toner does not contain extra components such as an organic solvent and a monomer, is a uniform particle having a uniform particle size and shape, has little change in charging performance due to the environment, and has color reproducibility (especially secondary color). Reproducibility), powder fluidity, low-temperature fixability, etc. are good, and the transfer rate to the recording medium is high. Therefore, by using the electrostatic charge image developer of the present invention, it is possible to stably form a high-quality image with high-definition, good color reproducibility, high image density, and few image defects such as fogging. .

  According to the present invention, a silicone resin and an amino group-containing silane coupling agent are included on the surface of a core material (preferably ferrite particles) as a carrier contained in the electrostatic charge image developer of the present invention. By using a coating layer made of a silicone resin composition for coating, a sufficient charge for developing an electrostatic image is imparted even if the electrostatic image developing toner used in combination does not contain a charge control agent. . Therefore, it is not necessary to add a charge control agent to the toner for developing an electrostatic image used in combination, and the production of the toner is further facilitated.

  According to the present invention, a carrier having an average particle diameter ratio of carrier to toner (average particle diameter of carrier / average particle diameter of toner) of 5 or more is indicated by the total projected area of the toner with respect to the total surface area of the carrier. By using so that the mixing ratio is 30 to 70%, the charge imparting property (toner chargeability) to the toner is further stabilized, and this electrostatic image developer is used for electrophotographic image formation for high-speed image formation. When applied to an apparatus, a high-definition and high-density high-quality image can be stably formed while minimizing toner consumption.

  According to the present invention, as a coating silicone resin composition containing 100 parts by weight of a crosslinkable silicone resin and containing 10 parts by weight or less of an amino group-containing silane coupling agent, charge imparting to the toner of the carrier is performed. As a result, the mechanical strength of the coating layer, the adhesion to the ferrite particles, etc. are improved, and a carrier capable of charging the toner stably over a long period of time can be obtained.

  According to the present invention, by using the electrostatic image developer of the present invention in an electrophotographic multicolor image forming method, it is excellent in image reproducibility including color reproducibility, high definition and high image density. Can be formed stably and for a long time.

The present invention provides a developer containing an electrostatic charge image developing toner and a multicolor image forming method.
[Toner for electrostatic image development]
The toner used in the present invention contains a pigment and a self-dispersing resin.

  Examples of pigments include blue pigments, brown pigments, cyan pigments, green pigments, violet pigments, magenta pigments, red pigments, yellow pigments, and other organic pigments, black pigments, and other inorganic pigments used in the field of electrophotographic image formation. Either can be used. Specifically, anthraquinone pigments, phthalocyanine blue pigments, phthalocyanine green pigments, pyrerin pigments, diazo pigments, monoazo pigments, pyranthrone pigments, perylene pigments, heterocyclic yellow pigments, quinacridone pigments, indigoids And pigments such as anthraquinone pigments, phthalocyanine blue pigments, pyrerin pigments, heterocyclic yellow pigments, quinacridone pigments, and thioindigoid pigments. Examples of the anthraquinone pigment include pigment red 43, pigment red 194 (perinone red), pigment red 216 (brominated pyrantrone red), and pigment red 226 (pyrantron red). Examples of the phthalocyanine blue pigment include copper phthalocyanine blue and pigment blue 15 which is a derivative thereof. Examples of the pyrerin pigments include Pigment Red 123 (Bell Million), Pigment Red 149 (Scarlet), Pigment Red 179 (Maroon), Pigment Red 190 (Red), Pigment Violet, Pigment Red 189 (Yellow Shade Red), and Pigment Red 224. Etc. Examples of the quinacridone pigment include Pigment Orange 48, Pigment Orange 49, Pigment Red 122, Pigment Red 192, Pigment Red 202, Pigment Red 206, Pigment Red 207, Pigment Red 209, Pigment Violet 19, and Pigment Violet 42. Examples of the thioindigoid pigment include Pigment Red 86, Pigment Red 87, Pigment Red 88, Pigment Red 181, Pigment Red 198, Pigment Violet 36, and Pigment Red Violet 38. As the black pigment, carbon black produced by various known methods can be used. A pigment can be used individually by 1 type or can use 2 or more types together. In the case of using two or more kinds in combination, the same color pigment may be used in combination, or a different color pigment may be used in combination. Among these pigments, it is preferable to appropriately select and use a pigment having good water dispersibility.

  The pigment content in the toner used in the present invention can be selected from a wide range depending on the required toner characteristics, but is preferably 0.1 to 20 parts by weight, more preferably 100 parts by weight of the self-dispersing resin. Is 0.1 to 15 parts by weight. If the amount is less than 0.1 parts by weight, the image density of the formed image may be insufficient. On the other hand, if the amount exceeds 20 parts by weight, the pigment dispersibility on the recording medium is deteriorated and the color reproducibility is not good. A sufficient image may be formed.

In the toner used in the present invention, as the binder resin, a carboxylic acid compound containing one or more selected from polyvalent carboxylic acids having 3 or more carboxyl groups in one molecule and acid anhydrides thereof, A self-dispersing resin containing a self-dispersing polyester (hereinafter referred to as “self-dispersing polyester (A)), which is a polycondensate obtained by polycondensation with an alcohol compound containing a monohydric alcohol, is used.

  The self-dispersing resin can contain a conventionally known self-dispersing resin in addition to the self-dispersing polyester (A). Such self-dispersing resins are not particularly limited as long as they can be dispersed in water, and include self-dispersing vinyl copolymer resins, self-dispersing polyurethanes, self-dispersing epoxy resins, and the like. Can be mentioned. These can be used individually by 1 type or can use 2 or more types together. As the hydrophilic group bonded to the main chain of these self-dispersing resins, an ionic group is preferable, and an anionic group is particularly preferable among them. Specific examples thereof include a carboxyl group, a phosphoric acid group, a phosphonic acid group, and a phosphinic acid group. These groups may exist in the form of a salt such as an ammonium salt or a metal salt. Since the sulfonic acid group may adversely affect the charging performance of the toner as described above, it is preferable to introduce it into the main chain of the self-dispersing resin in consideration of the quantitative aspect.

  The content of the self-dispersing polyester (A) in the self-dispersing resin is preferably 50% by weight or more of the total amount of the self-dispersing resin, more preferably 80% by weight or more of the total amount of the self-dispersing resin, and particularly preferably the self-dispersing method. 90% by weight or more of the total amount of resin. If it is less than 50% by weight, the resulting toner may be unsatisfactory in terms of color reproducibility and adhesion to a recording medium. Of course, the total amount of the self-dispersing resin may be the self-dispersing polyester (A).

  For the carboxylic acid compound that is the acid component monomer of the self-dispersing polyester (A), a polyvalent carboxylic acid (hereinafter referred to as “trivalent carboxylic acid”) having three or more carboxyl groups in one molecule is used. Furthermore, dicarboxylic acid, monocarboxylic acid, etc. are used as necessary. In particular, it is preferable to use a trivalent carboxylic acid and a dicarboxylic acid in combination.

  Known trivalent carboxylic acids can be used, and examples thereof include trimellitic acid, trimesic acid, pyromellitic acid, and acid anhydrides thereof. A trivalent carboxylic acid can be used individually by 1 type, or can use 2 or more types together.

  Known dicarboxylic acids can be used, such as terephthalic acid, isophthalic acid, orthophthalic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, anthracene dipropionic acid, anthracene dicarboxylic acid, diphenic acid, Sulfoterephthalic acid, 5-sulfoisophthalic acid, 4-sulfophthalic acid, 4-sulfonaphthalene-2,7dicarboxylic acid, aromatic dicarboxylic acids such as 5 (4-sulfophenoxy) isophthalic acid, p-oxybenzoic acid, p- (Hydroxyethoxy) benzoic acid and other aromatic oxycarboxylic acids, succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid and other aliphatic dicarboxylic acids, fumaric acid, maleic acid, itaconic acid, mesaconic acid, citraconic acid Aliphatic unsaturated dicarboxylic acids such as Aromatic unsaturated dicarboxylic acids, such as two-range acrylate, hexahydrophthalic acid, alicyclic dicarboxylic acids such as tetrahydrophthalic acid, and their anhydrides and the like. Among these, aromatic dicarboxylic acids are preferable, and terephthalic acid, isophthalic acid, and acid anhydrides thereof are particularly preferable. Dicarboxylic acid can be used individually by 1 type, or can use 2 or more types together.

Examples of monocarboxylic acids include benzoic acid, chlorobenzoic acid, bromobenzoic acid, parahydroxybenzoic acid, naphthalenecarboxylic acid, anthracenecarboxylic acid, 4-methylbenzoic acid, 3-methylbenzoic acid, salicylic acid, thiosalicylic acid, phenyl Acetic acid, lower alkyl esters thereof, sulfoammonium monoammonium salt, sulfobenzoic acid monosodium salt, cyclohexylaminocarbonylbenzoic acid, n-dodecylaminocarbonylbenzoic acid, tertiary butylbenzoic acid, tertiary butylnaphthalenecarboxylic acid, these And aromatic monocarboxylic acids such as acid anhydrides. Monocarboxylic acid can be used individually by 1 type, or can use 2 or more types together.

  When a trivalent carboxylic acid and a dicarboxylic acid are used in combination as the carboxylic acid compound, preferably 70 mol% or more, more preferably 80 mol% or more, particularly preferably 90 mol% or more of the total amount of the carboxylic acid compound is used. do it. At this time, the dicarboxylic acid is preferably composed of terephthalic acid and isophthalic acid. The proportion of terephthalic acid and isophthalic acid used is not particularly limited, but terephthalic acid is preferably used in an amount of 40 to 95 mol%, more preferably 60 to 95 mol%, particularly preferably 70 to 90 mol% of the total amount of dicarboxylic acid. The remainder may be isophthalic acid. If the example of a more specific usage rate is given, the usage rate of trivalent carboxylic acid is preferably 0.5 to 8 mol%, more preferably 0.5 to 6 mol% of the total amount of the carboxylic acid compound, and the remainder is dicarboxylic acid. It is better to use acid.

  When a trivalent carboxylic acid, a dicarboxylic acid and a monocarboxylic acid are used in combination as the carboxylic acid compound, it is preferably at least 70 mol%, more preferably at least 80 mol%, particularly preferably at least 90 mol% of the total amount of the carboxylic acid compound. The dicarboxylic acid may be used. In addition, when comprising dicarboxylic acid with a terephthalic acid and isophthalic acid, the same usage rate as the above may be sufficient. To give more specific examples of usage ratios, preferably 2 to 25 mol%, more preferably 5 to 20 mol% of trivalent carboxylic acid is used, preferably 0 to 0 of the total amount of carboxylic acid compound. 0.1 to 30 mol%, more preferably 0.1 to 10 mol% of dicarboxylic acid may be used, and the remainder may be monocarboxylic acid.

A polyhydric alcohol, a monoalcohol, etc. are used for the alcohol compound which is an alcohol component monomer of self-dispersing polyester (A). Known polyhydric alcohols can be used, and examples thereof include aliphatic polyhydric alcohols, alicyclic polyhydric alcohols, and aromatic polyhydric alcohols. Examples of the aliphatic polyhydric alcohol include ethylene glycol, propylene glycol, 1,3-propanediol, 2,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6- Hexanediol, neopentyl glycol, diethylene glycol, dipropylene glycol, 2,2,4-trimethyl-1,3-pentanediol, aliphatic diols such as polyethylene glycol, polypropylene glycol and polytetramethylene glycol, trimethylolethane, trimethylol Examples include triols such as propane, glycerin, and pentaerythritol, and tetraols. Examples of the alicyclic polyhydric alcohol include 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, spiroglycol, hydrogenated bisphenol A, ethylene oxide adduct and propylene oxide adduct of hydrogenated bisphenol A, tri Examples include cyclodecanediol and tricyclodecane dimethanol. Examples of aromatic polyhydric alcohols include para-xylene glycol, meta-xylene glycol, ortho-xylene glycol, 1,4-phenylene glycol, 1,4-phenylene glycol ethylene oxide adduct, bisphenol A, and bisphenol A ethylene oxide addition. And propylene oxide adducts. Furthermore, examples of the polyester polyol include a lactone polyester polyol obtained by ring-opening polycondensation of a lactone such as ε-caprolactone. Among these, aliphatic diols, alicyclic diols and the like are preferable. Among them, aliphatic diols such as ethylene glycol, propylene glycol and 2,3-butanediol, tricyclodecane dimethanol, cyclohexane diol, cyclohexane dimethanol Are preferred, and aliphatic diols such as ethylene glycol and propylene glycol are particularly preferred. Examples of the monoalcohol include aliphatic alcohols, aromatic alcohols, and alicyclic alcohols. Each of the polyhydric alcohol and monoalcohol can be used alone or in combination of two or more.

  The polyhydric alcohol is used in a proportion of 50 mol% or more, preferably 70 mol% or more, more preferably 80 mol% or more, particularly preferably 90 mol% or more of the total amount of the alcohol compound, and the remainder is a monoalcohol. Good. When ethylene glycol and / or propylene glycol is used as the polyhydric alcohol, the proportion of use is 50 mol% or more, preferably 60 mol% or more, more preferably 70 mol% or more of the total amount of the alcohol compound.

  The self-dispersing polyester (A) can be produced, for example, by polycondensing a carboxylic acid compound excluding a trivalent carboxylic acid and an alcohol compound and then reacting the resulting polycondensate with a trivalent carboxylic acid.

  The polycondensation reaction can be carried out according to a known method. For example, a mixture of a carboxylic acid compound excluding a trivalent carboxylic acid and an alcohol compound may be heated in the presence of a transesterification catalyst or an esterification catalyst. The use ratio of the carboxylic acid compound excluding the trivalent carboxylic acid and the alcohol compound is not particularly limited, and may be appropriately selected according to the physical properties of the polyester to be obtained. As the transesterification catalyst, known ones can be used, and examples thereof include metal acetates such as zinc acetate, lead acetate and magnesium acetate, metal oxides such as zinc oxide and antimony oxide, and metal alkoxides such as tetrabutoxy titanate. . Known esterification catalysts can be used, and examples thereof include organometallic compounds such as dibutyltin dilaurate and dibutyltin oxide, and metal alkoxides such as tetrabutoxytitanate. Heating is performed in two stages. For example, heating is performed at a temperature of about 150 to 220 ° C. for about 1 to 6 hours, and further heating is performed at a temperature of about 230 to 260 ° C. and preferably under reduced pressure for about 1 to 3 hours. Good. The polycondensate thus obtained can be directly subjected to a carboxyl group introduction reaction.

  Next, the reaction between the polycondensate obtained above and the trivalent carboxylic acid is performed by heating the mixture of the polycondensate and the trivalent carboxylic acid, for example, preferably in an inert gas atmosphere such as nitrogen gas. Is done by doing. The heating is performed at a temperature of about 180 to 220 ° C., for example, and is completed in about 0.5 to 3 hours. As a result, a self-dispersing polyester (A) having a carboxyl group introduced into the main chain of the polycondensate can be obtained. In this reaction, the trivalent carboxylic acid can be used in the form of a salt. At that time, the counter cation of the trivalent carboxylate is preferably a monovalent cation.

  The self-dispersing polyester (A) may be present in the form of an ammonium salt, an alkali metal salt, or the like by neutralizing the self-dispersing polyester (A) with ammonia, an alkali metal hydroxide or the like, if necessary.

  The self-dispersing polyester (A) thus obtained can be hydrophobized by further acid washing.

  The self-dispersing polyester (A) is a resin which has a wide molecular weight distribution and hardly causes gelation because it is synthesized mainly by condensation polymerization of a divalent or higher polyvalent carboxylic acid and a divalent or higher polyhydric alcohol. The chloroform-insoluble content is 0.5% by weight or less, preferably 0.25% by weight or less, and the acid value is 40 mgKOH / g or less, preferably 30 mgKOH / g or less.

Among the self-dispersing polyester (A), the glass transition point is preferably 40 to 80 ° C., more preferably 45 to 80 ° C., particularly preferably 50 to 75 ° C., or the softening point is preferably 80 to 150. It is preferable to use one having a temperature of 85 ° C., more preferably 85 to 150 ° C., particularly preferably 80 to 145 ° C. When the glass transition point is 40 ° C. or the softening point is lower than 80 ° C., the resulting toner is likely to be blocked, and the storage stability of the toner may be lowered. On the other hand, when the glass transition temperature is 80 ° C. or the softening point exceeds 150 ° C., the fixability of the toner obtained by the poly is lowered and the fixing roll for fixing the toner image transferred to the recording medium is heated to a high temperature. Since the necessity arises, the material of the fixing roll and the material of the recording medium to be transferred are limited.

  The self-dispersing polyester (A) uses the obtained toner as a color toner, improves the fixability to an OHP sheet, etc., and the offset region shifts to a high temperature side, and the toner is poorly fixed on the recording medium. In view of preventing the occurrence of the above, the molecular weight is preferably 2000 to 200000, more preferably 2000 to 50000, and the number average molecular weight is preferably 2000 to 30000, more preferably 3000 to 25000, and particularly preferably 3000. ~ 20,000. If the molecular weight exceeds 200,000, the self-dispersibility may be impaired, and if it is less than 2000, the durability as a toner may be reduced.

  The electrostatic image developing toner used in the present invention can contain a wax together with a pigment and a self-dispersing resin. Known waxes can be used, for example, natural waxes such as carnauba wax and rice wax, polypropylene wax, polyethylene wax and synthetic waxes such as Fischer and Lopush wax, coal-based wax such as montan wax, and alcohol-based wax. And ester waxes. One type of wax may be used alone, or two or more types may be used in combination. Although the wax is used in the form of particles, it can also be used in the form of a capsule in which the surface of the wax particles is coated with a synthetic resin. Capsule-shaped wax is preferable in that when it is added to a toner whose surface is covered with a synthetic resin and is not encapsulated, it is not exposed to the toner surface and the spent of the toner on the carrier can be improved. The amount of the wax used is preferably 0.5 to 20 parts by weight, more preferably 1 to 10 parts by weight with respect to 100 parts by weight of the self-dispersing resin.

  In the present invention, the toner particles may be modified by adding an external additive to the toner particles that have been formed into particles. As the external additives for surface modification, those commonly used in this field can be used, and examples thereof include water-dispersible inorganic particles such as silica and titanium oxide, and silicone resins. The particle size of the water-dispersible inorganic particles is not particularly limited, but preferably the average particle size is 1 μm or less, more preferably 0.01 to 0.8 μm. External additives can be used alone or in combination of two or more. Two or more water-dispersible inorganic particles can be used in combination. The amount of the external additive used is not particularly limited, but is preferably 1 to 10 parts by weight with respect to 100 parts by weight of the toner particles.

  In the present invention, a general toner additive such as a charge control agent or a release agent can be added as an external additive to the toner particles formed into particles.

[Method for producing toner for developing electrostatic image]
The electrostatic image developing toner used in the present invention can be produced by a production method including a raw material mixing step and an aggregate formation step. FIG. 1 is a flowchart showing an embodiment of a method for producing a toner for developing an electrostatic image. 1 includes a raw material mixing step S1, an aggregate formation step S2, a particle formation step S3, and a washing step S4.

The pigment, self-dispersing resin, wax and external additive used in the production method of the present invention are the same as those shown as the components of the electrostatic image developing toner used in the present invention.

  In the mixed liquid preparation step S1, the pigment aqueous dispersion and the aqueous dispersion of the self-dispersing resin are mixed to prepare a toner component mixed liquid.

  The pigment aqueous dispersion can be prepared by mixing the pigment and water. When an appropriate amount of a dispersant is added when mixing the pigment and water, the dispersibility of the pigment in water can be improved, and the dispersed particle diameter of the pigment can be reduced. Further, since the dispersant can be removed by a cleaning process described later, there is no possibility of changing the toner characteristics. As the dispersant, those commonly used in this field can be used, and examples thereof include a surfactant. Among the surfactants, anionic surfactants and nonionic surfactants are preferable. Although the pigment content in the pigment aqueous dispersion is not particularly limited, it is preferably about 0.1 to 20% by weight of the total amount of the pigment aqueous dispersion in consideration of work efficiency and the like.

  Mixing of the pigment and water is performed using, for example, a stirrer. Although any known emulsifier, disperser, etc. can be used as the stirrer, it can accept toner components such as pigments, self-dispersing resins, waxes and aqueous media in a batch or continuous manner, and has a heating means. The toner component and the aqueous medium are mixed under heating to produce toner as binder resin particles containing a pigment, and a device capable of releasing the toner in a batch or continuous manner is preferable. In addition, the emulsifier and the disperser can impart a shearing force to the mixture of the toner and the aqueous medium, which makes it easier to form the formed aggregate into particles having a uniform particle size and shape. This is preferable. Further, the emulsifier and the disperser preferably have at least one of a stirring unit and a rotating unit, and can mix the toner and the aqueous medium under stirring or rotation. In the emulsifier and the disperser, the mixing container for mixing the toner and the aqueous medium preferably has a heat retaining means. Specifically, for example, Ultra Turrax (trade name: manufactured by IKA Japan Co., Ltd.), Polytron homogenizer (trade name: manufactured by Kinematica Co., Ltd.), and TK Auto Homo Mixer (trade name: manufactured by Tokushu Kika Kogyo Co., Ltd.) Batch type emulsifiers such as Max Blend (manufactured by Sumitomo Heavy Industries, Ltd.), Ebara Milder (trade name: manufactured by Ebara Manufacturing Co., Ltd.), TK Pipeline Homo Mixer (trade name: manufactured by Special Machine Industries Co., Ltd.) ), TK homomic line flow (trade name: manufactured by Special Machine Engineering Co., Ltd.), Philmix (trade name: manufactured by Special Machine Engineering Co., Ltd.), colloid mill (trade name: manufactured by Shinko Pantech Co., Ltd.) ), Thrasher (trade name: manufactured by Mitsui Miike Chemicals Co., Ltd.), Trigonal wet milling machine (trade name: manufactured by Mitsui Miike Chemicals Co., Ltd.), Cavitron (trade name: manufactured by Eurotech Co., Ltd.) And continuous flow emulsifiers such as Fine Flow Mill (trade name: manufactured by Taiheiyo Kiko Co., Ltd.), Claremix (trade name: manufactured by M Technique Co., Ltd.), and Fillmix (trade name: Special Machine Engineering Co., Ltd.) Manufactured). These stirrers are not limited to the preparation of the pigment aqueous dispersion, the preparation of the aqueous dispersion of the self-dispersing resin, the preparation of the aqueous wax dispersion, the aqueous pigment dispersion and the aqueous dispersion of the self-dispersing resin And the addition of polyvalent metal salts to prepare aggregated particles of toner components, heating the aggregated particles, and cleaning toner particles obtained by heating the aggregated particles.

The aqueous dispersion of the self-dispersing resin can also be prepared by mixing the self-dispersing resin and water using a stirrer such as an emulsifier and a disperser, similarly to the pigment aqueous dispersion. In addition, an aqueous dispersion of the self-dispersing resin can be prepared while adjusting the average particle size and particle size distribution of the resin particles of the self-dispersing resin dispersed in water. For example, a method in which a self-dispersing resin and a water-soluble organic solvent are separately heated in advance to 50 to 200 ° C., and then both are mixed, and water is further added. Self-dispersing resin and water-soluble organic solvent A method of adding water to a mixture with (for example, a counter cation) and heating to 40 to 120 ° C., adding a self-dispersing resin to a mixture of water and a water-soluble organic solvent, and heating to 40 to 100 ° C. And a stirring method. In these methods, neutralization can be performed by adding an equivalent amount of an alkali agent to the acid value according to the acid value of the self-dispersing resin after the reaction. Examples of the water-soluble organic solvent include lower alcohols such as ethanol, butanol and isopropanol, cellosolves such as ethyl cellosolve and butyl cellosolve, ethers such as dioxane and tetrahydrofuran, ketones such as acetone and methyl ethyl ketone, and two or more of these. Or a mixed solvent thereof. In these methods, the self-dispersing resin, the water-soluble organic solvent and the amount of water used, the heating temperature, the type of the water-soluble organic solvent, the mixing time, and the like are appropriately selected, and the self-dispersing resin particle average particle size and particle size The distribution can be adjusted. In these methods, after the self-dispersing resin particles are formed, the water-soluble organic solvent is removed by heating or the like, whereby self-dispersing resin particles having a desired average particle size and particle size distribution are dispersed. An aqueous dispersion of a dispersible resin is obtained. The average particle size of the self-dispersing resin particles is not particularly limited, but is preferably 0.2 μm or less, more preferably 0.01 to 0.18 μm, and particularly preferably 0.01 to 0.15 μm. When the average particle size of the self-dispersing resin particles exceeds 0.2 μm, the aggregated particles obtained in the aggregate formation step S2 described later become too large, and it may be difficult to control the particle size of the toner. Although the content of the self-dispersing resin (resin particles) in the aqueous dispersion of the self-dispersing resin is not particularly limited, it is preferable in view of the ease of forming aggregated particles and work efficiency in the aggregate forming step S2 described later. Is 80 to 99% by weight of the total amount of the aqueous dispersion of the self-dispersing resin.

  In this step, an aqueous wax dispersion can be mixed together with the aqueous pigment dispersion and the aqueous dispersion of the self-dispersing resin. The aqueous dispersion of wax can be prepared by emulsifying wax particles or encapsulated wax in which the surfaces of the wax particles are coated with a synthetic resin in water.

  The pigment aqueous dispersion and the aqueous dispersion of the self-dispersing resin are mixed by using the same stirrer as described above, for example, by stirring at room temperature for about 1 to 5 hours. As a result, a toner component mixture is prepared.

  In the aggregate formation step S2, a polyvalent metal salt is added to the toner component mixed solution with stirring to form aggregates (aggregated particles) containing the toner component.

  In this step, the polyvalent metal salt used as the flocculant is a divalent or higher metal salt. Although it does not restrict | limit especially as a metal more than bivalence, Alkaline earth metals, such as magnesium, calcium, barium, Periodic Table 13 group elements, such as aluminum, etc. are mentioned, Magnesium, aluminum, etc. are preferable. Specific examples of the divalent or higher metal salt include magnesium sulfate, aluminum sulfate, barium chloride, magnesium chloride, calcium chloride, aluminum chloride, aluminum hydroxide, and magnesium hydroxide. Among these, when a dispersed pigment is used as the pigment, since both the pigment and the self-dispersing resin have a hydrophilic group or a hydrophilic group in the form of a salt, the pigment and the self-dispersing resin are ionically bonded. The divalent or higher metal salt obtained is preferred. In addition, magnesium sulfate, aluminum sulfate, or the like, which has a relatively high solubility in water, is preferable so that it can be easily removed by washing with pure water in the washing step S4 described later. Among these, the magnesium salt has an ion valence of 2 and an agglomeration rate is slower than an aluminum salt having an ionic valence of 3 and is optimal for controlling the particle size of the aggregated particles. The polyvalent metal salt can be used alone or in combination of two or more. In the present invention, a general organic compound flocculant such as dimethylaminoethyl (2,2 dimethylol) propionate can be used together with or in place of the polyvalent metal salt. The amount of the flocculant used is preferably 0.5 to 20 parts by weight with respect to 100 parts by weight of the toner component (total amount of pigment and self-dispersing resin or total amount of pigment, self-dispersing resin and wax). More preferably, it is 0.5-18 weight part, Most preferably, it is 1.0-18 weight part. If the amount is less than 0.5 part by weight, the aggregation effect may be insufficient, and if it exceeds 20 parts by weight, the aggregated particles may be too large.

  In this step, an aqueous dispersion of a self-dispersing resin can be added to the toner component mixed solution together with the polyvalent metal salt and mixed. In this case, it is preferable to reduce in advance the amount of resin contained in the aqueous dispersion of the self-dispersing resin used in this step from the aqueous dispersion of the self-dispersing resin used in the raw material mixing step S1.

  In this step, in order to prevent the aggregated particles to be reaggregated, a surfactant is added to the mixed system of the toner component mixed solution and the polyvalent metal salt, and the toner component mixed solution and the polyvalent metal are added. It is possible to adjust the pH of the mixed system to 8 or more by adding a general alkaline agent such as sodium hydroxide or potassium hydroxide to the mixed system with the salt.

  The mixing of the toner component mixed solution and the polyvalent metal salt is performed at room temperature to a temperature near the glass transition temperature (Tg) of the self-dispersing resin, preferably at room temperature, using the same general stirrer as described above. Done. At that time, it is preferable to use a stirrer capable of applying a mechanical shearing force. Thereby, the particle size and shape of the formed aggregated particles can be made more uniform.

  In the particle forming step S3, toner particles are formed by heating the aqueous medium containing the aggregated particles obtained in the aggregate forming step S2. The heating temperature is the glass transition temperature of the self-dispersing resin most contained in the aggregated particles or higher. As a result, toner particles having a particle size in the range of 1 to 20 μm and a uniform shape and particle size can be obtained.

  In this step, before heating the aqueous medium containing aggregated particles, an aqueous dispersion of a self-dispersing resin is added to the aqueous medium for the purpose of making the charging characteristics and shape of the toner particles more uniform. You can also The aqueous medium containing aggregated particles obtained in the aggregate formation step S2 includes aggregated particles with pigments attached to the surface, aggregated particles with pigments on the surface layer, aggregated particles with pigments inside the surface layer, and the like. It is. When toner particles are formed by heating the aggregated particles in such a state, there is a possibility that a toner containing toner particles having different charging characteristics may be obtained. There is a risk that the difference in charging characteristics between the case where the pigment is a conductive material such as carbon black and the case where the pigment is a colored pigment (cyan, magenta, yellow, etc.) is developed depending on the pigment used. It is forced to consider the design of the agent individually. On the other hand, since the charging characteristics of the toner are mainly governed by the properties of the toner particle surface, if the pigment is designed not to be directly exposed to the toner particle surface, a toner having substantially the same charging characteristics can be obtained regardless of the type of the pigment. can get. Therefore, by adding an aqueous dispersion of the self-dispersing resin, the charging characteristics of the toner particles are obtained by forming a self-dispersing resin coating layer on the surface of the aggregated particles where the pigment adheres to the surface or the pigment exists on the surface layer. The shape can be made more uniform. Furthermore, by providing a resin layer on the surface of the toner particles, a secondary effect that the spent of the carrier due to the wax can be prevented can be expected. When adding an aqueous dispersion of a self-dispersing resin, in order to prevent reaggregation of the agglomerated particles, a surfactant is added or the agglomerated particles are dispersed with a general alkali agent such as sodium hydroxide. The pH of the aqueous dispersion may be adjusted to 8 or higher. Moreover, when adding the aqueous dispersion of the self-dispersing resin in this step, the aqueous dispersion of the self-dispersing resin used in this step is changed from the aqueous dispersion of the self-dispersing resin used in the raw material mixing step S1. It is preferable to reduce in advance the amount of resin contained in.

  In the washing step S4, the toner particles (aggregated particles) obtained in the particle forming step S3 are washed. The cleaning of toner particles mainly includes unnecessary components other than toner components such as impurities that adversely affect the charging performance of the toner and unnecessary aggregating agents (polyvalent metal salts) that remain without being involved in aggregation. Done to get rid of. As a result, a toner containing no unnecessary components can be obtained.

  For cleaning the toner particles, pure water having an electric conductivity of 20 μS / cm or less is used. Such pure water can be obtained by a known method such as an activated carbon method, an ion exchange method, a distillation method, or a reverse osmosis method, and a plurality of methods may be combined.

  The toner particles are washed, for example, by separating only the toner particles from the aqueous medium containing the toner particles obtained in the particle formation step S3 by a general separation means such as filtration and centrifugation, and the toner particles are subjected to a conductivity of 20 μS / Washing with pure water having a conductivity of 20 μS / cm or less is preferably repeated until the conductivity of the water used for cleaning is 50 μS / cm or less. The temperature of the pure water is preferably equal to or lower than the lowest glass transition temperature of the self-dispersing binder resin in order to prevent toner particles from reaggregating. Such washing may be performed either batchwise or continuously. Further, during the cleaning with pure water, the cleaning with water having a pH of 6 or less may be performed once or twice or more. As a result, the impurities are more sufficiently removed. After the washing, the washed toner particles may be dried by a drier such as a vacuum drier if necessary. An appropriate amount of a surface modifier such as water-dispersible inorganic particles or silicone resin, a charge control agent, or a release agent may be added as an external additive to the toner particles obtained by drying.

  The electrostatic image developing toner used in the present invention thus obtained has an average particle size of preferably 10 μm or less, more preferably 2 to 9 μm, and particularly preferably 3 to 8 μm. When the average particle diameter exceeds 10 μm, the particle size distribution becomes broad in the toner production process, and the chargeability variation is large, which causes the image to be disturbed.

[Static charge image developer]
The electrostatic image developer of the present invention is a two-component developer containing the electrostatic image developing toner used in the present invention, which is produced according to the method for producing the electrostatic image developing toner used in the present invention, and a carrier. is there.

The electrostatic image developing toner used in the present invention is as described above.
The carrier is not particularly limited, but in consideration of imparting sufficient charge to the toner, the surface of the core material having an average particle diameter of 25 to 150 μm contains a silicone resin and an amino group-containing silane coupling agent. A carrier on which a coating layer made of a silicone resin composition is formed is preferred.

  Any carrier core material commonly used in this field can be used, and examples thereof include magnetic metals such as iron, copper, nickel and cobalt, and magnetic metal oxides such as ferrite and magnetite. When the core material of the carrier is a magnetic material as described above, a carrier suitable for a developer used in the magnetic brush development method can be obtained. The carrier core material preferably has a volume average particle diameter of 25 to 150 μm, and particularly preferably has a volume average particle diameter of 25 to 90 μm. In the present specification, the volume average particle diameter is a value measured using a particle size measuring device (trade name: Microtrac MT3000, manufactured by Nikkiso Co., Ltd.).

  The coating silicone resin composition for coating the core surface of the carrier contains a silicone resin and an amino group-containing silane coupling agent.

  The silicone resin is not particularly limited, and a silicone resin commonly used in this field can be used, but a crosslinkable silicone resin is preferable. As shown below, the crosslinkable silicone resin is a known silicone resin that is cured by crosslinking between hydroxyl groups bonded to Si atoms or a hydroxyl group and a group -OX by a heat dehydration reaction, a room temperature curing reaction, or the like.

[Wherein, a plurality of R are the same or different and each represents a monovalent organic group. The group -OX is an acetoxy group, an aminoxy group, an alkoxy group, an oxime group, and the like. ]

  As the crosslinkable silicone resin, either a heat curable silicone resin or a room temperature curable silicone resin can be used. In order to crosslink the thermosetting silicone resin, it is necessary to heat the resin to about 200 to 250 ° C. Although heating is not required to cure the room temperature curable silicone resin, it is preferably heated at 150 to 220 ° C. in order to shorten the curing time.

  Among the cross-linked silicone resins, those in which the monovalent organic group represented by R is a methyl group are preferable. Since the crosslinked silicone resin in which R is a methyl group has a dense crosslinked structure, when the resin coating layer of the carrier core material is formed using the crosslinked silicone resin, a good carrier such as water repellency and moisture resistance can be obtained. can get. However, if the cross-linked structure becomes too dense, the resin coating layer tends to become brittle, so selection of the molecular weight of the cross-linked silicone resin is important.

  Moreover, it is preferable that the weight ratio (Si / C) of silicon and carbon in the crosslinkable silicone resin is 0.3 to 2.2. If Si / C is less than 0.3, the hardness of the resin coating layer is lowered, and the carrier life and the like may be lowered. If Si / C exceeds 2.2, the charge imparting property of the carrier to the toner is likely to be affected by temperature change, and the resin coating layer may become brittle.

  In the present invention, a commercially available cross-linked silicone resin can be used. , KR280, KR282, KR261, KR260, KR255, KR266, KR251, KR155, KR152, KR214, KR220, X-4040-171, KR201, KR5202, and KR3093 (all manufactured by Shin-Etsu Chemical Co., Ltd.) Can be mentioned.

The cross-linked silicone resin can be used alone or in combination of two or more.
As the amino group-containing silane coupling agent, known ones can be used. For example, the general formula (Y) nSi (R) m (1)
[Wherein, m Rs are the same or different and each represents an alkyl group, an alkoxy group or a chlorine atom. n Y's are the same or different and each represents a hydrocarbon group containing an amino group. m and n each represent an integer of 1 to 3. However, m + n = 4. ]

In the general formula (1), examples of the alkyl group represented by R include a straight chain having 1 to 4 carbon atoms such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, and a tert-butyl group. Examples thereof include a chain or branched alkyl group, and among these, a methyl group, an ethyl group, and the like are preferable. Examples of the alkoxy group include linear or branched alkoxy groups having 1 to 4 carbon atoms such as a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, a butoxy group, an isobutoxy group, and a tert-butoxy group. Among these, a methoxy group, an ethoxy group, and the like are preferable. Examples of the hydrocarbon group containing an amino group represented by Y include a group — (CH ₂ ) a-X (wherein X is an amino group, an aminocarbonylamino group, an aminoalkylamino group, a phenylamino group or a dialkyl group). An amino group, a represents an integer of 1 to 4, and the group -Ph-X (wherein X is as defined above; -Ph- represents a phenylene group);

Specific examples of the amino group-containing silane coupling agent include the following.
H ₂ N (H ₂ C) ₃ Si (OCH ₃ ) ₃
H ₂ N (H ₂ C) ₃ Si (OC ₂ H ₅ ) _{3
H 2 N (H 2 C)} 3 Si (CH 3) (OCH 3) 2
_{H 2 N (H 2 C)} 2 HN (H 2 C) 3 Si (CH 3) (OCH 3) 2
H ₂ NOCHN (H ₂ C) ₃ Si (OC ₂ H ₅ ) ₃
H ₂ N (H ₂ C) ₂ HN (H ₂ C) ₃ Si (OCH ₃ ) _{3
H 2 N-Ph-Si (} OCH 3) 3 ( wherein -Ph- indicates a p- phenylene group.)
Ph-HN (H ₂ C) ₃ Si (OCH ₃ ) ₃ (wherein Ph- represents a phenyl group)
(H ₉ C ₄ ) ₂ N (H ₂ C) ₃ Si (OCH ₃ ) ₃

  The amino group-containing silane coupling agent can be used alone or in combination of two or more. The amount of the amino group-containing silane coupling agent is appropriately selected from a range that gives a sufficient charge to the toner and does not significantly reduce the mechanical strength of the resin coating layer. The amount is 10 parts by weight or less, more preferably 0.01 to 10 parts by weight with respect to parts.

  The silicone resin composition for coating can contain other resins together with the silicone resin as long as the preferable characteristics of the resin coating layer formed of the silicone resin (particularly, the cross-linked silicone resin) are not impaired. Examples of other resins include epoxy resins, urethane resins, phenol resins, acrylic resins, styrene resins, polyamides, polyesters, acetal resins, polycarbonates, vinyl chloride resins, vinyl acetate resins, cellulose resins, polyolefins, and copolymers thereof. Examples thereof include resins and compounded resins.

  The silicone resin composition for coating can contain a bifunctional silicone oil in order to further improve the moisture resistance, releasability, and the like of the resin coating layer formed of a silicone resin (particularly a crosslinked silicone resin).

The silicone resin composition for coating can be produced by mixing a predetermined amount of a silicone resin and an amino group-containing silane coupling agent and, if necessary, an appropriate amount of an additive such as a resin other than a silicone resin and a bifunctional silicone oil. As one form of the silicone resin composition for coating, a form of a solution in which the above components are dissolved in an organic solvent can be mentioned. The organic solvent is not particularly limited as long as it can dissolve the silicone resin. For example, aromatic hydrocarbons such as toluene and xylene, ketones such as acetone and methyl ethyl ketone, ethers such as tetrahydrofuran and dioxane, and higher alcohols. And a mixed solvent of two or more of these. If this solution-form silicone resin composition for coating (hereinafter referred to as “coat resin solution”) is used, a resin coating layer can be easily formed on the surface of the core material of the carrier. For example, a coating resin solution is applied to the surface of the carrier core material to form a coating layer, the organic solvent is volatilized and removed from the coating layer by heating, and the coating layer is heated or simply cured during or after drying. A resin coating layer is formed and a carrier is manufactured.

  Examples of the method for applying the coating resin liquid onto the surface of the carrier core material include an impregnation method in which the carrier core material is impregnated in the coating resin liquid, a spray method in which the coating resin liquid is sprayed on the carrier core material, and a floating state by a flowing air current. Examples thereof include a fluidized bed method in which a coating resin solution is sprayed onto a carrier core material. Among these, the fluidized bed method is preferable because a uniform resin coating layer such as a film thickness can be stably formed.

  A drying accelerator may be used for drying the coating layer. Known drying accelerators can be used, and examples thereof include lead such as naphthylic acid and octylic acid, metal soap such as iron, cobalt, manganese and zinc salts, and organic amines such as ethanolamine. A drying accelerator can be used individually by 1 type, or can use 2 or more types together.

  Although hardening of an application layer is performed, selecting heating temperature according to the kind of silicone resin, it is preferable to carry out by heating to about 150-280 degreeC, for example. Of course, when the silicone resin is a room temperature curable silicone resin, heating is not necessary, but for the purpose of improving the mechanical strength of the formed resin coating layer and shortening the curing time, 150 to 220. You may heat to about degreeC.

  The total solids concentration of the coating resin liquid (total measurement of silicone resin, amino group-containing silane coupling agent, resin other than silicone resin, bifunctional silicone oil, etc.) is not particularly limited, and is applied to the carrier core material. The film thickness of the cured resin coating layer is usually adjusted to 5 μm or less, preferably about 0.1 to 3 μm, taking into account the properties and the like.

  The carrier thus obtained preferably has a high electric resistance and a spherical shape, but even if it is conductive or non-spherical, the effect of the present invention is not lost.

  The electrostatic image developer of the present invention can be produced by mixing the electrostatic image developing toner used in the present invention with a carrier. The mixing ratio of the toner and the carrier is not particularly limited, but considering use in a high-speed image forming apparatus (40 sheets / min or more for A4 size images), the volume average particle diameter of the carrier / the volume average particle of the toner. The ratio of the total projected area of toner (the total projected area of all toner particles) to the total surface area of the carrier (total surface area of all carrier particles) with the diameter of 5 or more (total projected area of toner / total surface area of carrier) X100) may be mixed so as to be 30 to 70%. As a result, the chargeability of the toner can be stably maintained in a sufficiently good state, and it can be used as a suitable developer that can form a high-quality image stably and for a long time even in a high-speed image forming apparatus. For example, if the volume average particle diameter of the toner is 6.5 μm, the volume average particle diameter of the carrier is 90 μm, and the ratio of the total projected area of the toner to the total surface area of the carrier is 30 to 70%, 100 parts by weight of the carrier in the developer On the other hand, it contains about 2.2 to 5.3 parts by weight of toner. When high-speed development is performed with such a developer, the toner consumption amount and the toner supply amount supplied to the developing tank of the developing device in accordance with the toner consumption are maximized, and the supply-demand balance is not impaired. When the amount of carrier in the developer is more than about 2.2 to 5.3 parts by weight, the charge amount tends to be lower and desired development characteristics cannot be obtained, and the toner is more than the toner supply amount. The amount of consumption is increased, and sufficient charge cannot be imparted to the toner, leading to degradation of image quality. Further, if the amount is small, the charge amount tends to be high, and it becomes difficult for the toner from the carrier to be separated by an electric field, resulting in deterioration of image quality.

The projected area of the toner was calculated as follows. The specific gravity of the toner was set to 1.0, and the calculation was made based on the volume average particle diameter obtained with a Coulter Counter (trade name: Coulter Counter Multisizer II, manufactured by Beckman Coulter, Inc.). The number of toners with respect to the toner weight to be mixed is calculated, and the total toner area is calculated by toner number × toner area (calculated assuming a circle). Similarly, the total area of the carrier was calculated from the weight of the carrier mixed based on the particle diameter obtained from Microtrac (trade name: Microtrac MT3000, manufactured by Nikkiso Co., Ltd.). The carrier specific gravity at this time was 4.7. The mixing ratio was calculated by the total toner area / total carrier area × 100 obtained above.

[Multicolor image forming method]
The multicolor image forming method of the present invention is characterized by using the electrostatic image developer of the present invention in an electrophotographic image forming method.

  In electrophotographic image formation, for example, an image forming body having a photosensitive layer capable of forming an electrostatic charge image on the surface, charging means for charging the surface of the image forming body to a predetermined potential, and image formation in which the surface is charged. An exposure unit that irradiates the body with signal light according to image information to form an electrostatic charge image (electrostatic latent image) on the surface of the image forming body, and a developer carrying carrier, and converts the developer into an electrostatic charge image Supplying and developing means for developing the electrostatic latent image to form a toner image; transfer means for transferring the toner image on the surface of the image forming body to the recording medium; and fixing for fixing the toner image on the surface of the recording medium to the recording medium This is performed using an electrophotographic image forming apparatus that includes a cleaning unit that removes toner, paper dust, and the like remaining on the surface of the image carrier after the toner image is transferred to the recording medium.

  When developing an electrostatic charge image, the developer carried on the developer carrying carrier is carried to a developing area formed in the vicinity of the developer carrying carrier and the image forming body, and the developer carrying carried. A developing process for visualizing an electrostatic image on the image forming body by reversal development under an oscillating electric field formed by applying an AC bias voltage to the body is repeatedly performed, and a plurality of different colors are formed on the image forming body. A multicolor toner image is formed by superimposing the toner images.

  According to the multicolor image forming method of the present invention, it is excellent in image reproducibility including color reproducibility, and a high-definition and high-image density multicolor image can be stably formed over a long period of time.

  Reference Examples, Examples, Comparative Examples and Test Examples will be specifically described below, but the present invention is not limited to these Examples unless it exceeds the gist. In the following, “part” means “part by weight”. Unless otherwise specified, “%” indicates “% by weight”.

  The acid value, glass transition temperature and number average molecular weight of the self-dispersing polyester were measured according to the following methods.

[Acid value]
The measurement was performed according to JIS K 0070.

[Glass-transition temperature]
Using a differential scanning calorimeter (trade name: DSC210, manufactured by Seiko Denshi Kogyo Co., Ltd.), the temperature was raised to 200 ° C., the temperature was lowered from 200 ° C. to 0 ° C. at a rate of 10 ° C./min, and the sample cooled down to 10 ° C. / The peak chart shown when the temperature was raised in minutes was determined, and the temperature was determined as the temperature of the intersection of the baseline extension line below the maximum peak temperature and the tangent line indicating the maximum slope from the peak rising portion to the peak apex.

[Number average molecular weight]
The molecular weight distribution was measured by the following gel permeation chromatography (GPC) method, and the number average molecular weight was calculated from the obtained molecular weight portion.
Measuring device: CO-8010 (manufactured by Tosoh Corporation)
Analysis column: GMHLX + G3000HXL (manufactured by Tosoh Corporation)
Sample concentration: 0.5 g / 100 ml tetrahydrofuran Eluent: Tetrahydrofuran (40 ° C.)
Eluent flow rate: 1 ml / min Standard sample: monodisperse polystyrene

(Reference Example 1)
[Manufacture of carriers (1) to (5)]
The use amount (parts) of silicone resin, aminosilane coupling agent and toluene shown in Table 1 below were stirred for 5 minutes with a three-one motor to prepare a coating resin solution. This coat resin solution was mixed with a ferrite core material having a volume average particle diameter (μm) and a use amount (parts) shown in Table 1 below, and the mixture was further introduced into a stirrer and further mixed. Toluene was removed from the obtained mixture under reduced pressure and heating to form a coating layer on the surface of the ferrite core material. This was heated at 200 ° C. for 1 hour to cure the coating layer to form a resin coating layer, which was passed through a 100 mesh screen to produce carriers (1) to (5). In Table 1, the following silicone resins and aminosilane coupling agents were specifically used.
Silicone resin (I) Product name: SR2411, manufactured by Toray Dow Corning Co., Ltd.
(20% silicone resin solution)
Silicone resin (b) Product name: SR2410, manufactured by Toray Dow Corning Co., Ltd.
(20% silicone resin solution)
Aminosilane coupling agent (C) Product name: TSL8331, GE Toshiba Silicone Co., Ltd. (100% solution)
Aminosilane coupling agent (d) Product name: SH6020, manufactured by Toray Dow Corning Co., Ltd. (100% solution)

  In each of the obtained carriers (1) to (5), a silicone resin layer having a thickness of about 1 μm was formed on the surface of the ferrite core material.

(Reference Example 2)
[Synthesis of self-dispersing polyester (A1) and preparation of aqueous dispersion (A2)]
In an autoclave equipped with a thermometer and a stirrer, 137 parts of dimethyl terephthalate, 55 parts of dimethyl isophthalate, 68 parts of ethylene glycol, 175 parts of ethylene oxide adduct (average molecular weight 350) of bisphenol A and 0.1 part of tetrabutoxy titanate (catalyst) The mixture was heated at 150 to 220 ° C. for 180 minutes to conduct transesterification, and then heated to 240 ° C., then the pressure in the reaction system was gradually reduced, and after 30 minutes, the reaction was continued at 70 mm for 70 minutes. . Next, the inside of the autoclave was replaced with nitrogen gas, the internal pressure was changed to atmospheric pressure, 2 parts of trimellitic anhydride was added while maintaining the temperature at 200 ° C., and the reaction was carried out for 70 minutes. The acid value was 15 KOHmg, the glass transition temperature was 64 ° C. A self-dispersing polyester (A1) having a number average molecular weight of 7800 was produced.

  Next, 100 parts of the self-dispersible polyester (A1) obtained above, 48 parts of butanol, 12 parts of methyl ethyl ketone, and 20 parts of isopropanol were added to a four-necked 10 liter separable flask equipped with a thermometer, a condenser and a stirring blade. The solution was charged and heated to 70 ° C. to prepare a self-dispersing polyester (A1) solution. To this solution, 270 parts of a 1N aqueous ammonia solution was added so as to be equivalent to the acid value of the self-dispersing polyester resin (A1), and the mixture was stirred for 30 minutes while maintaining 70 ° C. Was added to obtain an aqueous dispersion of a self-dispersing polyester. The obtained aqueous dispersion was put into a distillation flask, and the organic solvent was removed by reducing the pressure with a vacuum pump at a temperature of 70 ° C. Finally, the solid content was adjusted with deionized water to obtain a self-dispersible polyester aqueous dispersion (A2) having a solid content concentration of 30%. The volume average particle diameter of the resin particles of the self-dispersing polyester (A1) in this aqueous dispersion was 0.095 μm. The volume average particle size was measured with a laser diffraction / scattering particle size distribution analyzer (trade name: Microtrac UPA-EX150, manufactured by Nikkiso Co., Ltd.).

(Reference Example 3)
[Synthesis of Self-dispersing Polyester (B1) and Preparation of Water Dispersion (B2)]
An autoclave equipped with a thermometer and a stirrer is charged with 38 parts of 1,5-naphthalenedicarboxylic acid methyl ester, 96 parts of dimethyl terephthalate, 58 parts of dimethyl isophthalate, 136 parts of ethylene glycol and 0.1 part of tetrabutoxy titanate (catalyst). Subsequent operations were carried out in the same manner as in Reference Example 2 except that the amount of trimellitic anhydride added was changed from 2 parts to 10 parts, and the self value having an acid value of 14 KOHmg, a glass transition temperature of 65 ° C. and a number average molecular weight of 3500 was determined. Dispersible polyester (B1) was produced.

  A self-dispersing polyester aqueous dispersion (B2) having a solid content concentration of 30% is the same as in Reference Example 2, except that the self-dispersing polyester (B1) obtained above is used instead of the self-dispersing polyester (A1). ) Was prepared. The volume average particle diameter of the resin particles of the self-dispersing polyester (B1) in this aqueous dispersion was 0.080 μm.

(Reference Example 4)
[Production of self-dispersing polyester (C1) and preparation of aqueous dispersion (C2)]
In an autoclave equipped with a thermometer and a stirrer, 112 parts of dimethyl terephthalate, 76 parts of dimethyl isophthalate, 6 parts of 5 sodium sulfodimethylisophthalate, 96 parts of ethylene glycol, 50 parts of propylene glycol and 0.1 part of tetrabutoxy titanate (catalyst) Was transesterified by heating at 180-230 ° C. for 120 minutes. Subsequently, the reaction system was heated to 250 ° C. and reacted for 60 minutes under a reaction system pressure of 1 to 10 mmHg. Self-dispersible polyester (C1) having an acid value of 0.1 KOH mg, a glass transition temperature of 58 ° C. and a number average molecular weight of 3100 Manufactured.

  A self-dispersing polyester aqueous dispersion (C2) having a solid content concentration of 30% is the same as in Reference Example 2, except that the self-dispersing polyester (C1) obtained above is used instead of the self-dispersing polyester (A1). ) Was prepared. The volume average particle diameter of the resin particles of the self-dispersing polyester (C1) in this aqueous dispersion was 0.2 μm.

  Table 2 summarizes the characteristics of the self-dispersing polyester aqueous dispersions obtained in Reference Examples 2 to 4.

(Reference Example 5)
[Preparation of blue pigment aqueous dispersion (I)]
50 parts of a cyan pigment (trade name: Eupolene Blue 69-1501, manufactured by BASF), 5 parts of an anionic surfactant (trade name: Neogen R, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) and 223 parts of ion-exchanged water Using zirconia beads having a diameter of 0.5 mm, the mixture was dispersed for 40 minutes with a planetary ball mill (manufactured by Fritsch). Subsequently, the mixture was put into a homogenizer (trade name: PT3000, manufactured by Polytron), stirred at room temperature for 20 minutes, further dispersed for 20 minutes with an ultrasonic homogenizer (manufactured by Nippon Seiki Co., Ltd.), and a volume average particle size of 0.10 μm. A blue pigment aqueous dispersion (I) was prepared in which the blue pigment was dispersed in water. The average particle diameter of the pigment and wax particles described later was measured with a laser diffraction / scattering particle size distribution measuring apparatus (Microtrac UPA-EX150).

(Reference Example 6)
[Preparation of red pigment aqueous dispersion (II)]
A red pigment having an average particle size of 0.09 μm is dispersed in water in the same manner as in Reference Example 5 except that a magenta pigment (trade name: Eupollen Red 47-9001, manufactured by BASF) is used instead of the cyan pigment. A red pigment aqueous dispersion (II) was prepared.

(Reference Example 7)
[Preparation of aqueous dispersion of yellow pigment (III)]
A yellow pigment having a volume average particle size of 0.08 μm is submerged in water by operating in the same manner as in Reference Example 5 except that a yellow pigment (trade name: Eupolene Yellow 09-6101, manufactured by BASF) is used instead of the cyan pigment. A dispersed yellow pigment aqueous dispersion (III) was prepared.

(Reference Example 8)
[Preparation of aqueous dispersion of black pigment (IV)]
50 parts of carbon black (trade name: Mogal L, manufactured by Cabot Corp.), 5 parts of nonionic surfactant (trade name: Nonipol 400, manufactured by Sanyo Chemical Co., Ltd.) and 223 parts of ion-exchanged water are zirconia having a diameter of 0.5 mm. Use beads to disperse in a planetary ball mill (manufactured by Fritsch) for 40 minutes, then add to a homogenizer (PT3000) and stir at room temperature for 20 minutes to disperse carbon black with a volume average particle size of 0.13 μm in water. A black pigment aqueous dispersion (IV) was prepared.

(Reference Example 9)
[Preparation of aqueous wax dispersion]
50 parts of paraffin wax (trade name: HNP10, melting point 72 ° C., manufactured by Nippon Seiwa Co., Ltd.), 5 parts of an anionic surfactant (Neogen R) and 161 parts of ion-exchanged water are put into a stainless steel beaker with jacket. Disperse with a homogenizer (PT3000) for 30 minutes under heating at ℃, then transfer to a pressure discharge type homogenizer (manufactured by Nippon Seiki Co., Ltd.) and perform a dispersion treatment for 20 minutes with heating at 90 ° C. A wax aqueous dispersion having a solid content concentration of 25% in which 4 μm wax fine particles were dispersed in water was prepared.

(Examples 1-4)
[Raw material mixing process]
Self-dispersing polyester aqueous dispersion, pigment aqueous dispersion and wax aqueous dispersion are mixed in the amounts used (parts, all in terms of solid content) shown in Table 3 below, and pure water is added as necessary to obtain solids. A toner raw material mixture having a partial concentration of 10% was prepared. In this step, 85% of the usage amount shown in Table 3 was used as the self-dispersing polyester aqueous dispersion.

[Aggregate formation step]
The toner mixture obtained above is put into a Max blend stirrer (manufactured by NGK Co., Ltd.), and 270 parts of a 1% aqueous solution of magnesium chloride (flocculating agent) is dropped little by little with stirring (1500 rpm). This mixed solution was stirred for 1 hour to form aggregates (aggregated particles). Next, a self-dispersing polyester aqueous dispersion (remaining 15% of the amount used shown in Table 3) was mixed, and 30 parts of a 1% aqueous solution of magnesium chloride was added dropwise little by little. Agitation was performed to form aggregates (aggregated particles).

[Particle formation process]
The aqueous medium containing the aggregate obtained above was heated to 75 ° C. and stirred for 30 minutes, and further stirred at 94 ° C. for 20 minutes to form toner particles having a uniform particle size and shape.

[Washing process]
The aqueous medium containing the toner particles obtained above was filtered to separate the toner particles. A washing operation of mixing 4 parts of pure water with 1 part of the toner particles and separating the toner particles by filtration was performed 5 times. Next, 1 part of the toner particles is washed with 4 parts of an aqueous hydrochloric acid solution (pH 2), and the same washing operation as described above is performed three times, followed by drying using a vacuum dryer. Was prepared.

  In addition, the pure water used for the cleaning uses pure water having a conductivity of 0.5 μS / cm prepared from tap water using an ultrapure water production apparatus (trade name: Ultra Pure Water System CPW-102, manufactured by ADVANTEC). did. The pH and conductivity of water were measured using a Lacom tester (trade name: EC-PHCON10, manufactured by Inoue Seieido).

  To 100 parts of the toner particles obtained above, 0.7 parts of silica particles having an average primary particle diameter of 20 nm surface-treated with a silane coupling agent were mixed to prepare toners of Examples 1 to 4.

(Example 5)
Same as Example 1 except that the total amount of the self-dispersing polyester aqueous dispersion was used in the raw material mixing step, and the addition of the self-dispersing polyester aqueous dispersion and the second magnesium chloride aqueous solution were not performed in the aggregate formation step. Thus, toner particles were produced to prepare the toner of Example 5.

(Comparative Example 1)
Toner particles were produced in the same manner as in Example 1 except that the self-dispersing polyester aqueous dispersion (C2) and the pigment aqueous dispersion (IV) were used in the amounts used (parts, all in terms of solid content) shown in Table 3. A toner of Comparative Example 1 was prepared.

(Comparative Example 2)
Toner particles of Comparative Example 2 were prepared in the same manner as in Example 4 except that the flocculant was changed to a 1.5% aqueous solution of alkylbenzylammonium chloride (trade name: SANISOL B50, manufactured by Kao Corporation). Was prepared.

  For the toners obtained in Examples 1 to 5 and Comparative Examples 1 and 2, the volume average particle diameter, the coefficient of variation, and the average circularity were evaluated.

  Further, 5 parts of the toners of Examples 1 to 5 and Comparative Examples 1 and 2 and 100 parts of carrier (1) were mixed to prepare the developer of the present invention. This developer was evaluated for image density, fog, environmental stability and transfer rate. Each evaluation was specifically performed as follows. The results are also shown in Table 3. “◯” in Table 3 means that the evaluation item is very excellent.

[Volume average particle size and coefficient of variation]
The volume average particle diameter (μm) and coefficient of variation of the toner particles were measured using a particle size measuring device (trade name: Coulter Counter Multisizer II, manufactured by Beckman Coulter, Inc.) with a measurement particle count of 50000 and an aperture diameter of 100 μm. . Regarding the coefficient of variation, those having a coefficient of variation of 40 or less were evaluated as “◯”, and those having a coefficient of variation exceeding 40 were evaluated as “x”.

[Average circularity]
The average circularity of the toner particles was calculated from the following equation by measuring the peripheral length of the projected image of the toner particles using a flow type particle image analyzer (trade name: FPIA-2000, manufactured by Toa Medical Electronics Co., Ltd.). . Went. The average circularity is usually a value of 1 or less.
Average circularity = (perimeter of a perfect circle having the same area as the projected image) / (perimeter of the projected image)

[Image density]
The image density was evaluated by measuring the optical density of the evaluation image with a spectrocolorimetric densitometer (trade name: X-Rite 938, manufactured by Japan Planographic Printing Equipment Co., Ltd.). Those having an optical density of 1.2 or more were evaluated as “◯”, and those having an optical density of less than 1.2 were evaluated as “×”. For the evaluation image, the developing device was modified for the developer of the present invention and a digital full-color multifunction peripheral (trade name: AR-C150, manufactured by Sharp Corporation) and the developer of the present invention were used, and the toner adhesion amount was The color toner image was transferred to a full-color exclusive paper (trade name: PP106A4C, manufactured by Sharp Corporation) adjusted to 0.6 mg / cm ² and fixed by an external fixing device.

[Cover]
The fog was evaluated by calculating the fog density W (%) from the following formula. The case where the fog density W was 2.0% or less was evaluated as “◯”, and the case where the fog density W exceeded 2.0% was evaluated as “X”.
W (%) = [(W1-W2) / W1] × 100

  W1 in the formula is the whiteness of A4 size full-color dedicated paper (trade name: PP106A4C, manufactured by Sharp Corporation). W2 is the whiteness of a white portion of a copy image obtained by copying three originals including a white circle having a diameter of 55 mm. The whiteness was measured using a whiteness meter (trade name: Z-Σ90 COLOR MEASURING SYSTEM, manufactured by Nippon Denshoku Industries Co., Ltd.).

[Environmental stability]
A predetermined amount of the developer of the present invention is put into a developing tank, and stored in an environment of (a) a temperature of 5 ° C. and a humidity of 10% and (b) a temperature of 35 ° C. and a humidity of 80% for one day and night. Rotate for 2 minutes at the same rotational speed as AR-C150), measure the charge amount of the toner at that time, and measure the charge amount of the toner under the high temperature and high humidity condition of (b) with respect to the low temperature and low humidity condition of (a). The relative ratio (change rate) was calculated and evaluated. When the relative ratio (rate of change) was 75% or less, “◯” was evaluated, and when it exceeded 75%, “X” was evaluated.

[Transfer rate]
The transfer rate T (%) was calculated from the following formula. When the transfer rate T was 90% or more, “◯” was evaluated, and when it was less than 90%, “X” was evaluated.
T (%) = [Mp / (Md + Mp)] × 100

  In the equation, Mp is the toner weight on the paper surface on which the predetermined chart is copied. Mp is the toner weight remaining on the surface of the image forming body (electrophotographic photosensitive member) when copying a predetermined chart. Here, the predetermined chart is one in which patches of 4 cm × 4 cm are arranged at the four corners on the A4 paper (inside 1.5 cm from the edge of the paper) and at the center.

  From Table 3, according to Examples 1 to 5, the width of the particle size distribution is narrow (the coefficient of variation is small), the image density and the transfer rate are high, the occurrence of fog is small, and the environmental stability is various. It can be seen that it is possible to produce a toner that maintains the toner characteristics at a high level.

  Further, comparison between Example 4 and Example 5 shows that the environmental stability of the charging property of the toner is further improved by repeatedly performing the aggregate forming operation in the aggregate forming process.

  Further, from the comparison between Example 4 and Comparative Example 1, it is found that the toner using the carboxyl group-containing self-dispersible polyester is more environmentally stable in the carboxyl group-containing self-dispersible polyester and the sulfonic acid group-containing self-dispersible polyester. It can be seen that this is far superior.

  Further, from the comparison between Example 4 and Comparative Example 2, when a polyvalent metal salt is used as the aggregating agent, toner particles having a small volume average particle diameter, a small volume average particle diameter fluctuation range, and a high average circularity are obtained. It turns out that it can produce stably.

(Examples 6-8 and Comparative Examples 3-4)
5 parts of the toner obtained in Example 1 and 100 parts of the carrier obtained in Production Examples 1 to 5 are mixed, and the developer of the present invention (using Carriers 1 to 3) and the developer of Comparative Example (Carrier 4). ˜5) were prepared.

[Charge amount]
20 g of the developer of the present invention and the comparative example obtained above was weighed in a 100 cc plastic bottle and stirred on two rolls, and the charge amount after 1 hour was measured with a charge amount measuring device (Trek). . When the measured charge amount was 20 or more and 50 or less, the evaluation was “◯”, and the others were evaluated as “X”.

[Image density]
Image density was evaluated in the same manner as in Example 1 using 500 g of the developer of the present invention and the comparative example. The evaluation criteria were also the same.

  From the above results, when the area ratio (total toner projected area / carrier total surface area) is 30 to 70% and the volume average particle diameter ratio (carrier volume average particle diameter / toner volume average particle diameter) is 5 or more, the charge amount Can be seen to stabilize.

  Further, as in Comparative Example 3, it is understood that when the carrier (4) containing no aminosilane coupling agent is used in the resin coating layer, the charge amount and thus the image density is lowered. Further, as in Comparative Example 4, when the amount of the aminosilane coupling agent in the resin coating layer exceeds 10% with respect to the silicone resin, the charge amount increases remarkably and a desired image density cannot be obtained. .

  The developer for developing an electrostatic image of the present invention can be suitably used in an image forming apparatus such as an electrophotographic copying machine, a printer, or a fax machine.

It is a flowchart which shows the manufacturing method of the toner for electrostatic image image development used by this invention.

Claims (6)

Containing a pigment and a self-dispersing resin containing a self-dispersing polyester;
Self-dispersing polyester
A polycondensate of a polycarboxylic acid containing three or more carboxyl groups in one molecule and a carboxylic acid compound containing one or more selected from acid anhydrides thereof and an alcohol compound containing a polyhydric alcohol. An electrostatic charge image developer comprising: an electrostatic charge developing toner; and a carrier coated with a silicone resin containing an aminosilane coupling agent.   The carrier is formed by forming a coating layer made of a coating silicone resin composition containing a silicone resin and an amino group-containing silane coupling agent on the surface of a core material having a volume average particle diameter of 25 to 150 µm. Item 2. The electrostatic image developer according to Item 1.   The electrostatic charge image developer according to claim 2, wherein the core material is ferrite particles.   The ratio of the average particle diameter of the carrier and the electrostatic charge developing toner (average particle diameter of the carrier / average particle diameter of the electrostatic charge image developing toner) is 5 or more, and the electrostatic charge developing toner has a total surface area of the carrier. The electrostatic charge image developer according to claim 1, wherein a mixing ratio represented by a total projected area is 30 to 70%.   The static silicone resin composition according to any one of claims 1 to 4, wherein the coating silicone resin composition contains 10 parts by weight or less of an amino group-containing silane coupling agent with respect to 100 parts by weight of the crosslinked silicone resin. Charge image developer. Vibration formed by the developer carrying carrier transporting the developer to a developing region formed in the vicinity of the developer carrying carrier and the image forming body, and applying an AC bias voltage to the developer carrying carrier. A multicolor toner image is formed by repeatedly performing a developing process in which an electrostatic charge image on an image forming body is visualized by a reversal developing method under an electric field, and superimposing a plurality of toner images having different colors on the image forming body. In the multicolor image forming method,
A multicolor image forming method using the electrostatic image developer according to any one of claims 1 to 5 as a developer.

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