JP2010096847A - Electrostatic latent image developing toner and method for producing the same, electrostatic latent image developer, toner cartridge, process cartridge and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide: an electrostatic latent image developing toner which suppresses direct contact of a release agent exposed to a toner surface in contact of toner particles with each other and in contact with a carrier, a member of an image forming apparatus, etc., and improves the elution property of the release agent in fixing; a method for producing the toner; an electrostatic latent image developer using the toner; a toner cartridge; a process cartridge; and an image forming apparatus. <P>SOLUTION: The electrostatic latent image developing toner includes a binder resin and a release agent and has an exposed part where the release agent is exposed to a toner surface, wherein the exposed surface of the exposed part exists on the inner side of the toner surface. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electrostatic latent image developing toner and a manufacturing method thereof, an electrostatic latent image developer, a toner cartridge, a process cartridge, and an image forming apparatus.

  In electrophotography, generally, a latent image is electrically formed by various means on the surface of a photoreceptor (latent image holding member) using a photoconductive substance, and the formed latent image is used as a developer. After developing with toner, a toner image is formed, and the toner image is transferred to the surface of a transfer material such as paper via an intermediate transfer member as necessary, and fixed by heating, pressing, heating and pressing, etc. An image is formed through a plurality of processes. The toner remaining on the surface of the photoreceptor is generally cleaned by a cleaning process using a blade.

  As a fixing technique for fixing the toner image transferred to the surface of the transfer target, heat to be fixed by inserting the transfer target having the toner image transferred between a pair of rolls composed of a heating roll and a pressure roll. A roll fixing method is common. As a similar technique, a fixing method in which one or both of the rolls is replaced with a belt is also known. Since these techniques are in direct contact with the image as compared with other fixing methods, a fast and robust image can be obtained and the energy efficiency is high.

On the other hand, in recent years, toners that are particularly excellent in fixing properties (for example, low-temperature fixability and offset resistance) have been desired, and toners aimed at improving the fixing properties have been disclosed as described below.
Specifically, for example, Patent Document 1 discloses a toner manufactured by pulverizing a fibrous body in which a wax component is present in the center for the purpose of obtaining low-temperature fixability and a wide non-offset temperature region. Yes.
Patent Document 2 discloses a toner in which wax is unevenly distributed in the vicinity of the surface with a core-shell structure for the purpose of achieving both improved heat-resistant storage stability of the toner and prevention of offset at the time of fixing.

Patent Document 3 discloses a method for producing a toner in which a colorant and a wax existing on the particle surface are dissolved in a solvent, and the colorant and the wax are not exposed on the surface.
Patent Document 4 discloses a toner in which wax is unevenly distributed in the vicinity of the surface for the purpose of achieving both storage stability and releasability.
Patent Document 5 discloses a toner in which a composite resin component is contained in a release agent in order to improve release properties, the release agent system is enlarged, and the toner is localized on the toner surface.
Patent Document 6 discloses a pulverized toner whose theoretical wax exposure is in a specific range for the purpose of preventing filming development and carrier contamination and improving releasability.
JP 2006-285198 A JP 2005-99233 A JP 2005-309253 A JP 2004-145243 A Japanese Patent Laid-Open No. 2003-255584 JP 2002-107996 A

  An object of the present invention is to prevent the release agent exposed on the toner surface from coming into direct contact when contacting toners, a carrier, a member of an image forming apparatus, and the like, and elution of the release agent at the time of fixing. It is an object of the present invention to provide a toner for developing an electrostatic latent image that improves the properties.

The above-mentioned subject is achieved by the following present invention.
That is, the invention according to claim 1
For developing an electrostatic latent image comprising a binder resin and a release agent, and having an exposed portion where the release agent is exposed on the surface of the toner, wherein the exposed surface of the exposed portion is present inside the surface of the toner Toner.

The invention according to claim 2
2. The electrostatic latent image developing toner according to claim 1, wherein the number of the exposed portions is 0.01 or more and 5.0 or less per particle of the toner.

The invention according to claim 3
A resin particle dispersion adjusting step of adjusting the resin particle dispersion in which the first resin particles are dispersed;
A resin particle dispersion adjusting step of adjusting a resin particle dispersion in which the first resin particles as the binder resin particles are dispersed;
A release agent particle dispersion adjusting step for adjusting a release agent particle dispersion in which release agent particles that are particles of the release agent are dispersed;
A mixed solution adjusting step of mixing the resin particle dispersion and the release agent particle dispersion to adjust a mixed solution containing the first resin particles and the release agent particles;
In the mixed solution, an aggregated particle adjusting step of adjusting aggregated particles formed by the aggregation of the first resin particles earlier than the release agent particles;
A resin-coated particle adjusting step of adjusting the resin-coated particles formed by coating the aggregated particles with the second resin particles that are particles of the binder resin;
3. A fusion / union step of fusing and uniting the resin-coated particles by heating to a temperature higher than the glass transition temperature of the first resin particles or the second resin particles. The method for producing a toner for developing an electrostatic latent image described in 1.

The invention according to claim 4
When the coagulation value of the first resin particles is Fp (mol / g) and the coagulation value of the release agent particles is Fw (mol / g), the following formulas (1), (2), and (3) The method for producing a toner for developing an electrostatic latent image according to claim 3, wherein:
Formula (1): 1 × 10 ⁻⁵ ≦ Fp ≦ 1 × 10 ⁻¹
Formula (2): 1 × 10 ⁻⁵ ≦ Fw ≦ 1 × 10 ⁻¹
Formula (3): Fp ≦ Fw

The invention according to claim 5
The electrostatic latent image developing toner according to claim 1 or 2, or the electrostatic latent image developing toner according to any one of claim 3 or claim 4, wherein the electrostatic latent image developing toner is produced. An electrostatic latent image developing developer comprising at least an electrostatic latent image developing toner.

The invention according to claim 6
Toner that is removed from the image forming apparatus and supplied to at least developing means provided in the image forming apparatus is stored.
The toner is produced by the method for producing an electrostatic latent image developing toner according to claim 1 or 2, or an electrostatic latent image developing toner according to any one of claims 3 or 4. A toner cartridge, which is a manufactured toner for developing an electrostatic latent image.

The invention according to claim 7 provides:
A process cartridge comprising at least a developer holder and containing the developer for developing an electrostatic latent image according to claim 5.

The invention according to claim 8 provides:
A latent image carrier,
An electrostatic latent image forming means for forming an electrostatic latent image on the surface of the latent image holding member;
Developing means for developing the electrostatic latent image as a toner image with a developer;
Transfer means for transferring the toner image formed on the latent image holding member onto a transfer target;
Fixing means for fixing the toner image transferred onto the transfer object,
The image forming apparatus according to claim 5, wherein the developer is a developer for developing an electrostatic latent image.

  According to the first aspect of the present invention, the toner, the carrier, and the image forming apparatus are compared with the case where the exposed surface of the release agent existing inside the toner surface does not exist on the toner surface. When coming into contact with the member or the like, direct contact of the release agent exposed on the toner surface is suppressed, and release agent elution at the time of fixing is improved.

  According to the second aspect of the present invention, the release agent elution at the time of fixing is improved and the elution amount of the release agent at the time of fixing as compared with the case where the number of exposed surfaces of the release agent is not taken into consideration. Therefore, uneven distribution of the release agent on the image surface due to too much is suppressed.

  According to the invention of claim 3, any one of the aggregated particle adjusting step and the resin-coated particle adjusting step of adjusting the aggregated particles formed by the aggregation of the first resin particles earlier than the release agent particles. Compared to the case where the toner does not contain toner, it is possible to prevent the release agent exposed on the toner surface from coming into direct contact when the manufactured toner comes into contact with each other, the carrier, the member of the image forming apparatus, and the like, and , The release agent elution rate at the time of fixing is improved.

  According to the fourth aspect of the present invention, compared to the case where the coagulation values of the first resin particles and the release agent particles are not taken into consideration, the produced toner is further produced by using the toner, the carrier, and the image forming apparatus. Direct contact of the release agent exposed on the toner surface when contacting with a member or the like is suppressed, and the release agent elution rate during fixing is improved.

  According to the fifth aspect of the present invention, the toner, the carrier, the members of the image forming apparatus, and the like are compared with the case where the exposed surface of the release agent existing inside the toner surface is not present on the toner surface. When the toner is brought into contact with the toner, it is possible to prevent the release agent exposed on the toner surface from coming into direct contact, and to improve the release agent elution property at the time of fixing.

  According to the invention of claim 6, the toner, the carrier, the members of the image forming apparatus, etc., compared with the case where the exposed surface of the release agent existing inside the toner surface is not present on the toner surface. When the toner is brought into contact with the toner, it is possible to prevent the release agent exposed on the toner surface from coming into direct contact, and to improve the release agent elution property at the time of fixing.

  According to the seventh aspect of the present invention, the toner, the carrier, the members of the image forming apparatus, and the like are compared with the case where the exposed surface of the release agent existing inside the toner surface is not present on the toner surface. When the toner is brought into contact with the toner, it is possible to prevent the release agent exposed on the toner surface from coming into direct contact, and to improve the release agent elution property at the time of fixing.

  According to the eighth aspect of the present invention, the toner, the carrier, the member of the image forming apparatus, and the like are compared with the case where the exposed surface of the release agent existing inside the toner surface is not present on the toner surface. When the toner is brought into contact with the toner, it is possible to prevent the release agent exposed on the toner surface from coming into direct contact, and to improve the release agent elution property at the time of fixing.

Hereinafter, the present invention will be described in detail.
<Toner for electrostatic latent image development>
The electrostatic latent image developing toner of the present embodiment (hereinafter sometimes simply referred to as “toner”) includes a binder resin and a release agent. Further, the toner surface has a release agent exposure portion where the release agent is exposed, and the release agent exposure surface of the release agent exposure portion exists inside the toner surface.
Hereinafter, the structure of the toner surface and the periphery of the release agent exposed portion will be described with reference to the drawings.

  FIG. 1A is a view schematically showing the surface of toner particles of the present embodiment, and FIG. 1B is a release agent on the surface of toner particles shown in FIG. It is the schematic diagram which expanded and showed the exposure part periphery. FIG. 2 is a 2-2 end view of FIG.

As shown in FIGS. 1 and 2, the toner particles 210 include a resin 212 existing inside the toner particles 210, a release agent 214 embedded in the surface of the resin 212, and a release agent 214. And a coating resin layer 216 that covers part of the resin 212.
An opening 224 is present in the coating resin layer 216, and the release agent 214 is exposed without being covered in the opening 224, thereby constituting a release agent exposed portion. That is, at the release agent exposed portion, the release agent 214 is observed from the outside through the opening 224 of the coating resin layer 216, and the surface of the release agent 214 observed from the outside is the release agent exposed surface 220. .
The release agent exposed surface 220 exists inside the surface of the toner particles 210. Further, the release agent exposed surface 220 is more toner than the virtual plane 228 in contact with the opening edge peripheral resin surface 226 within 0.5 μm from the opening edge 222 of the opening 224 in the coating resin surface 218 of the coating resin layer 216. It is preferable to be inside the particle 210.

The toner of the present embodiment has a release agent exposure portion (hereinafter, may be referred to as a “concave release agent exposure portion”) in which the release agent exposure surface 220 exists inside the surface of the toner particles 210. Therefore, it is possible to prevent the release agent exposed on the toner surface from coming into direct contact with the toner or the carrier, and to improve the release agent elution property at the time of fixing. The reason is not clear, but is presumed as follows.
For example, like the toner manufactured by the kneading and pulverizing method, the release agent exposure surface 220 of the release agent exposure portion is convex (that is, the release agent exposure is more than the virtual plane 228 in contact with the opening edge peripheral resin surface 226). When the surface 220 protrudes to the outside of the toner particles 210), the release agent exposed to the convex shape directly contacts other toner particles, carrier particles, members of the image forming apparatus, and the like. . Therefore, it is considered that powder flowability and heat storage properties are deteriorated, and filming (film formation) is likely to occur due to toner adhering to the surface of the photoreceptor.
However, as described above, the toner of the present embodiment has the release agent exposed surface 220 located on the inner side of the surface of the toner particles 210, so that the release agent is prevented from coming into direct contact with other particles or members. The Therefore, it is presumed that the powder fluidity and the heat storage property are improved and the filming of the photoreceptor and the like is suppressed as compared with the case where the surface where the release agent is exposed is convex.

On the other hand, if the release agent is not exposed on the surface of the toner particles by coating the whole particle with resin, the release layer is released by the resin layer covering the surface when the release agent is eluted during fixing. The elution of the agent may be hindered, resulting in a slow elution rate. Further, due to insufficient elution of the release agent, the release agent on the image surface to be formed may be unevenly distributed. When the image surface release agent is unevenly distributed, when the image surface comes into contact with a member heated to a high temperature (for example, 80 ° C.) (for example, a decurler member that stretches the printed matter after fixing), the image surface release agent. May be detached and adhere to the member, resulting in image defects (white spots) or contamination of the member.
However, in the toner of this embodiment, since the release agent is exposed on the toner surface in the concave release agent exposure portion, the release agent is not exposed on the image surface during fixing compared to the case where the release agent is not exposed. It dissolves quickly and the dissolution is improved. Therefore, the uneven distribution of the release agent on the image surface is suppressed, the image fixed on the recording medium is easily peeled off from the fixing member (improving the release property), and the image defect and the contamination of the member are suppressed.

The number of exposed portions of the concave mold release agent per toner particle is preferably 0.01 or more and 5.0 or less, more preferably 0.05 or more and 3.0 or less, and more preferably 0.1 or more and 2 or less. Less than 0.0 is more preferable.
When the number of the exposed portions of the concave mold release agent is within the above range, the release rate of the release agent at the time of fixing is improved, and the amount of the release agent eluted at the time of fixing is too large. The uneven distribution of the release agent is suppressed. Specifically, when the number of the concave mold release agent exposed portions is within the above range, the release agent elution rate is improved and the image is improved as compared with the case where the number of the concave mold release agent exposed portions is smaller than the above range. The uneven distribution of the release agent on the surface is suppressed, the release property is improved, and image defects and member contamination are suppressed. Further, since the number of the concave mold release agent exposed portions is in the above range, the amount of the release agent elution amount at the time of fixing is too large compared to the case where the number of the concave mold release agent exposed portions is larger than the above range. The uneven distribution of the release agent on the image surface is suppressed, and image defects and member contamination associated therewith are suppressed.

The method for confirming whether or not the release agent exposure surface 220 is inside the surface of the toner particle 210 in the concave release agent exposure portion is as follows.
Specifically, first, the opening edge 222 is confirmed by the following usage. The toner is dyed with a 0.5% by weight aqueous solution of ruthenium tetroxide, and the toner surface is observed with a scanning electron microscope (SEM). Since the non-crystalline resin used as the binder resin for the toner has many double bond portions and is easily dyed, the coated resin surface 218 appears brighter in the reflected electron image than other portions. On the other hand, since the release agent 214 is difficult to be dyed, the release agent exposed surface 220 appears darker in the reflected electron image than other portions. Therefore, the boundary surface between the binder resin and the release agent on the surface of the toner particle 210, that is, the opening edge 222 is confirmed.

  Next, the surface shapes of the opening edge peripheral resin surface 226 and the release agent exposed surface 220 of 0.5 μm from the opening edge 222 confirmed by the above method are measured by a scanning probe microscope system (AFM) manufactured by Toyo Technica. Then, by analyzing the measurement result, it is confirmed whether or not the release agent exposed surface 220 is inside the surface of the toner particle 210 with respect to the virtual plane 228 in contact with the opening edge peripheral resin surface 226.

  The number of the concave mold release agent exposed portions is obtained by observing 100 toner particles by the SEM and averaging the number of the concave mold release agent exposed portions present in the respective toner particles.

  When the toner is externally added by an external additive, the external additive is removed in advance by the following method and then observed. As a method for removing the external additive, specifically, an amount of the external additive toner necessary for observation is dispersed in ion-exchanged water to which a dispersant such as a surfactant is added, and an ultrasonic homogenizer (US-300T :( (Nippon Seiki Seisakusho Co., Ltd.) etc. to separate the external additive and toner by applying ultrasonic waves. Thereafter, only the toner is taken out by filtration and washing.

Hereinafter, the configuration of the toner of this embodiment will be described in more detail.
The toner contains at least a binder resin and a release agent, and may contain other components as necessary. Examples of the binder resin include a crystalline resin and an amorphous resin, but it is preferable to use a crystalline resin and an amorphous resin in combination. Specifically, for example, a crystalline resin is used as the resin 212 and an amorphous resin is used as the resin of the coating resin layer 216, or a crystalline resin and an amorphous resin are used in combination as the resin 212 of the coating resin layer 216. Examples thereof include a method using an amorphous resin as the resin.

[Binder resin]
-Crystalline resin-
Examples of crystalline resins include crystalline polyester resins, polyalkylene resins, long-chain alkyl (meth) acrylate resins, etc., but more rapid changes in viscosity due to heating, mechanical strength and low-temperature fixing. From the viewpoint of coexistence with the above, it is desirable to use a crystalline polyester resin.

  In addition, as the polymerizable monomer component constituting the crystalline resin, a polymerizable monomer having a linear aliphatic component rather than a polymerizable monomer having an aromatic component in order to easily form a crystal structure. The body is desirable. Furthermore, in order not to impair the crystallinity, it is desirable that the constituent component derived from the polymerizable monomer is 30 mol% or more for each single species in the polymer. In particular, when two or more kinds of polymerizable monomers are essential in a polyester resin or the like, it is desirable that each essential constituent polymerizable monomer type has the same configuration.

Hereinafter, the crystalline polyester resin will be mainly described as a representative of the crystalline resin.
The melting temperature of the crystalline polyester resin is preferably in the range of 50 to 100 ° C, more preferably in the range of 55 to 90 ° C, and still more preferably in the range of 60 to 85 ° C. When the melting temperature is lower than 50 ° C., toner storage properties such as blocking of the stored toner and storage properties of the fixed image after fixing may become difficult. Further, when the melting temperature exceeds 100 ° C., sufficient low-temperature fixability may not be obtained.
The melting temperature of the crystalline polyester resin was determined as the peak temperature of the endothermic peak obtained by the differential scanning calorimetry (DSC).

  In the present embodiment, the “crystalline polyester resin” includes not only a polymer having a 100% polyester structure as a constituent component but also a polymer (copolymer) obtained by polymerizing a component constituting a polyester and other components. means. However, in the latter case, the component other than the polyester constituting the polymer (copolymer) is 50% by mass or less.

  The crystalline polyester resin is synthesized from, for example, a polyvalent carboxylic acid component and a polyhydric alcohol component. In the present embodiment, a commercially available product may be used as the crystalline polyester resin, or a synthesized product may be used.

  Examples of the polyvalent carboxylic acid component include oxalic acid, succinic acid, glutaric acid, adipic acid, peric acid, azelaic acid, sebacic acid, 1,9-nonanedicarboxylic acid, 1,10-decanedicarboxylic acid, 1,12 -Aliphatic dicarboxylic acids such as dodecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, 1,18-octadecanedicarboxylic acid; phthalic acid, isophthalic acid, terephthalic acid, naphthalene-2,6-dicarboxylic acid, malonic acid, mesaconic acid Aromatic dicarboxylic acids such as dibasic acids such as, and the like, and anhydrides and lower alkyl esters thereof are also included, but not limited thereto.

  Examples of the trivalent or higher carboxylic acid include 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, and the like, and anhydrides thereof. And lower alkyl esters. These may be used individually by 1 type and may use 2 or more types together.

Moreover, as a polyvalent carboxylic acid component, the dicarboxylic acid component which has a sulfonic acid group other than the said aliphatic dicarboxylic acid and aromatic dicarboxylic acid may be contained.
Furthermore, as a polyvalent carboxylic acid component, you may contain the dicarboxylic acid component which has a double bond other than the said aliphatic dicarboxylic acid and aromatic dicarboxylic acid.

  The polyhydric alcohol component is preferably an aliphatic diol, more preferably a linear aliphatic diol having a main chain portion having 7 to 20 carbon atoms. When the aliphatic diol is branched, the crystallinity of the polyester resin is lowered and the melting temperature may be lowered. Further, when the main chain portion has less than 7 carbon atoms, when polycondensation with an aromatic dicarboxylic acid, the melting temperature becomes high and fixing at low temperature may be difficult, while the main chain portion has 20 carbon atoms. Exceeding the above range makes it difficult to obtain practical materials. The number of carbon atoms in the main chain portion is more preferably 14 or less.

  Specific examples of the aliphatic diol suitably used for the synthesis of the crystalline polyester include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6. -Hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13- Examples include, but are not limited to, tridecanediol, 1,14-tetradecanediol, 1,18-octadecanediol, 1,14-eicosandecanediol, and the like. Among these, considering availability, 1,8-octanediol, 1,9-nonanediol, and 1,10-decanediol are desirable.

  Examples of the trivalent or higher alcohol include glycerin, trimethylolethane, trimethylolpropane, pentaerythritol and the like. These may be used individually by 1 type and may use 2 or more types together.

  Among the polyhydric alcohol components, the content of the aliphatic diol is preferably 80 mol% or more, and more preferably 90% or more. When the content of the aliphatic diol is less than 80 mol%, the crystallinity of the polyester resin is lowered and the melting temperature is lowered, so that toner blocking resistance, image storage stability, and low-temperature fixability may be deteriorated. .

  If necessary, a polycarboxylic acid or a polyhydric alcohol may be added at the final stage of the synthesis for the purpose of adjusting the acid value or the hydroxyl value. Examples of polycarboxylic acids include aromatic carboxylic acids such as terephthalic acid, isophthalic acid, phthalic anhydride, trimellitic anhydride, pyromellitic acid, naphthalenedicarboxylic acid; maleic anhydride, fumaric acid, succinic acid, alkenyl Aliphatic carboxylic acids such as succinic anhydride and adipic acid; and alicyclic carboxylic acids such as cyclohexanedicarboxylic acid.

  Examples of polyhydric alcohols include aliphatic diols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butanediol, hexanediol, neopentyl glycol, glycerin; cyclohexanediol, cyclohexanedimethanol, hydrogenated bisphenol A, etc. And aromatic diols such as bisphenol A ethylene oxide adduct and bisphenol A propylene oxide adduct.

The crystalline polyester resin is produced at a polymerization temperature of 180 to 230 ° C., and the reaction system is depressurized as necessary to carry out the reaction while removing water and alcohol generated during the condensation.
When the polymerizable monomer is not dissolved or compatible at the reaction temperature, a solvent having a high boiling point may be added as a solubilizer and dissolved. In the polycondensation reaction, the dissolution auxiliary solvent is distilled off. If there is a polymerizable monomer having poor compatibility in the copolymerization reaction, the polymerizable monomer having poor compatibility and the polymerizable monomer and the acid or alcohol to be polycondensed are condensed in advance. And then polycondensation with the main component.

  Examples of the catalyst used in the production of the polyester resin include alkali metal compounds such as sodium and lithium; alkaline earth metal compounds such as magnesium and calcium; zinc, manganese, antimony, titanium, tin, zirconium, and germanium. Metal compounds such as: phosphorous acid compounds; phosphoric acid compounds; and amine compounds.

  Specific examples of the catalyst include sodium acetate, sodium carbonate, lithium acetate, lithium carbonate, calcium acetate, calcium stearate, magnesium acetate, zinc acetate, zinc stearate, zinc naphthenate, zinc chloride, manganese acetate, Manganese naphthenate, titanium tetraethoxide, titanium tetrapropoxide, titanium tetraisopropoxide, titanium tetrabutoxide, antimony trioxide, triphenylantimony, tributylantimony, tin formate, tin oxalate, tetraphenyltin, dibutyltin dichloride, dibutyltin Oxide, diphenyltin oxide, zirconium tetrabutoxide, zirconium naphthenate, zirconyl carbonate, zirconyl acetate, zirconyl stearate, zirconyl octylate Germanium oxide, triphenyl phosphite, tris (2,4-di -t- butyl-phenyl) phosphite, ethyltriphenylphosphonium bromide, triethylamine, compounds such as triphenyl amine.

  The acid value of the crystalline polyester resin (the number of mg of KOH required to neutralize 1 g of resin) is desirably in the range of 3.0 to 30.0 mgKOH / g, and 6.0 to 25.0 mgKOH / g. It is more desirable to be in the range of 8.0 to 20.0 mgKOH / g.

  When the acid value is lower than 3.0 mgKOH / g, the dispersibility in water is lowered, and thus it may be very difficult to produce emulsified particles by a wet process. Further, since stability as emulsified particles during aggregation is significantly reduced, it may be difficult to produce an efficient toner. On the other hand, when the acid value exceeds 30.0 mgKOH / g, the hygroscopicity as a toner increases and the toner may be easily affected by the environment.

  The weight average molecular weight (Mw) of the crystalline polyester resin is preferably 6,000 to 35,000. When the molecular weight (Mw) is less than 6,000, the toner may permeate the surface of a recording medium such as paper at the time of fixing to cause fixing unevenness, or the strength of the fixed image against bending resistance may be reduced. On the other hand, when the weight average molecular weight (Mw) exceeds 35,000, the viscosity at the time of melting becomes too high, and the temperature for reaching a viscosity suitable for fixing may be increased, resulting in the deterioration of the low-temperature fixability. There is a case.

  The weight average molecular weight is measured by gel permeation chromatography (GPC). The molecular weight measurement by GPC was performed with a THF solvent using a Tosoh column / TSKgel Super HM-M (15 cm) using a Tosoh GPC / HLC-8120 as a measuring device. The weight average molecular weight is calculated from the measurement result using a molecular weight calibration curve prepared with a monodisperse polystyrene standard sample.

  The content of the crystalline polyester resin in the toner is preferably in the range of 3 to 40% by mass, more preferably in the range of 4 to 35% by mass, and still more preferably in the range of 5 to 30% by mass. When the content of the crystalline polyester resin is less than 3% by mass, sufficient low-temperature fixability may not be obtained. When the content is more than 40% by mass, sufficient toner strength and fixed image strength cannot be obtained. There is a case where an adverse effect on the charging property is also caused.

  The crystalline resin containing the above crystalline polyester resin is mainly composed of a crystalline polyester resin synthesized from an aliphatic polymerizable monomer (hereinafter sometimes referred to as “crystalline aliphatic polyester resin”). 50 mass% or more) is desirable. Furthermore, in this case, the constituent ratio of the aliphatic polymerizable monomer constituting the crystalline aliphatic polyester resin is preferably 60 mol% or more, and more preferably 90 mol% or more. As the aliphatic polymerizable monomer, the above-mentioned aliphatic diols and dicarboxylic acids are preferably used.

-Amorphous resin-
Examples of the amorphous resin include known resin materials such as styrene / acrylic resin, epoxy resin, polyester resin, polyurethane resin, polyamide resin, cellulose resin, polyether resin, polyolefin resin, etc. Polyester resins are particularly desirable.

  Since the compatibility with the crystalline polyester resin is improved by using the amorphous polyester resin, the non-crystalline polyester resin is also reduced in viscosity with a decrease in viscosity at the melting temperature of the crystalline polyester resin. Therefore, it is advantageous for low temperature fixability. In addition, since the wettability with the crystalline polyester resin is good, the dispersibility of the crystalline polyester resin inside the toner is improved, and the exposure of the crystalline polyester resin to the toner surface is suppressed. Is suppressed. For this reason, it is also desirable from the viewpoint of improving the strength of the toner and the strength of the fixed image.

Hereinafter, the amorphous polyester resin will be mainly described as a representative of the amorphous resin.
The amorphous polyester resin that is desirably used is obtained, for example, by condensation polymerization of polyvalent carboxylic acids and polyhydric alcohols.
Examples of polyvalent carboxylic acids include aromatic carboxylic acids such as terephthalic acid, isophthalic acid, phthalic anhydride, trimellitic anhydride, pyromellitic acid, naphthalene dicarboxylic acid; maleic anhydride, fumaric acid, succinic acid, alkenyl Aliphatic carboxylic acids such as succinic anhydride and adipic acid; alicyclic carboxylic acids such as cyclohexanedicarboxylic acid, and the like. These polyvalent carboxylic acids are used alone or in combination. Among these polyvalent carboxylic acids, it is desirable to use aromatic carboxylic acids, and in order to take a cross-linked structure or a branched structure in order to ensure good fixability, a tricarboxylic acid or higher carboxylic acid (trimellitic acid) together with a dicarboxylic acid. And acid anhydrides thereof) are preferably used in combination.

  Examples of the polyhydric alcohol in the non-crystalline polyester resin include aliphatic diols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butanediol, hexanediol, neopentylglycol, glycerin, etc .; cyclohexanediol, cyclohexane Examples thereof include alicyclic diols such as dimethanol and hydrogenated bisphenol A; aromatic diols such as an ethylene oxide adduct of bisphenol A and a propylene oxide adduct of bisphenol A. One or more of these polyhydric alcohols may be used. Among these polyhydric alcohols, aromatic diols and alicyclic diols are preferred, and among these, aromatic diols are more desirable. In order to secure better fixability, a trihydric or higher polyhydric alcohol (glycerin, trimethylolpropane, pentaerythritol) may be used in combination with the diol in order to form a crosslinked structure or a branched structure.

The amorphous polyester resin preferably has a glass transition temperature (Tg) in the range of 50 to 80 ° C. If Tg is lower than 50 ° C., problems may occur in terms of toner storage stability and fixed image storage stability. If it is higher than 80 ° C., it may not be fixed at a lower temperature than in the past.
The Tg of the amorphous polyester resin is more preferably 50 to 65 ° C.

As the non-crystalline polyester resin, when the solubility parameter SPA of the crystalline polyester resin and the solubility parameter SPB of the non-crystalline polyester resin are used, it is desirable that both satisfy the relationship of the following formula (10).
SPB-SPA <0.7 Formula (10)

The solubility parameter (hereinafter also referred to as “SP value”) is the same as the method of Fedors et al. [Polym. Eng. Sci. , Vol14, p147 (1974)], and calculated from the following formula (11) from the polymerizable monomer structure.
SP value = (ΣΔei / ΣΔvi) ^1/2 Equation (11)
(In the above formula, Δei represents the evaporation energy of atoms or atomic groups, and Δvi represents the molar volume of atoms or atomic groups, respectively.)

  In Formula (10), when the difference between SPB and SPA is 0.7 or more, the compatibility between the crystalline polyester resin and the amorphous polyester resin is lowered, and the internal dispersibility of the crystalline polyester resin is deteriorated. However, the chargeability may be deteriorated due to the toner surface exposure. In addition, the strength of the toner and the strength of the fixed image may be reduced due to a decrease in wettability between the crystalline polyester resin and the non-crystalline polyester resin.

In addition, manufacture of the said amorphous polyester resin is performed according to the case of the said crystalline polyester resin.
As described above, the crystalline resin and the non-crystalline resin have been described using the crystalline polyester resin and the non-crystalline polyester resin, but the contents other than the production of the polyester resin apply to other crystalline resins and non-crystalline resins. Is done.

[Release agent]
Examples of the release agent include paraffin wax such as low molecular weight polypropylene and low molecular weight polyethylene; silicone resin; rosins; rice wax; carnauba wax;
The melting temperature of the release agent is preferably 50 ° C. to 100 ° C., more preferably 60 ° C. to 95 ° C.
The content of the release agent in the toner is preferably 0.5 to 15% by mass, and more preferably 1.0 to 12% by mass. If the content of the release agent is less than 0.5% by mass, peeling failure may occur particularly in oilless fixing. When the content of the release agent is more than 15% by mass, the image quality and the reliability of image formation may be deteriorated, for example, the fluidity of the toner is deteriorated.

[Colorant]
The toner may contain a colorant as necessary. The colorant may be a dye or a pigment, but a pigment is desirable from the viewpoint of light resistance and water resistance.
Desirable colorants include, for example, carbon black, aniline black, aniline blue, calcoil blue, chrome yellow, ultramarine blue, DuPont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue, malachite green oxalate, lamp black, Rose Bengal, Quinacridone, Benzicine Yellow, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 57: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 185, C.I. I. Pigment red 238, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 180, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 74, C.I. I. Pigment blue 15: 1, C.I. I. And known pigments such as CI Pigment Blue 15: 3.

  The content of the colorant in the toner is preferably in the range of 1 to 30 parts by mass with respect to 100 parts by mass of the binder resin. It is also effective to use a surface-treated colorant or a pigment dispersant as necessary. By selecting the type of the colorant, yellow toner, magenta toner, cyan toner, black toner and the like can be obtained.

[Other additives]
In addition to the above components, the toner may contain various components such as an internal additive, a charge control agent, inorganic powder (inorganic particles), and organic particles as necessary.
Examples of the internal additive include metals such as ferrite, magnetite, reduced iron, cobalt, nickel, and manganese, alloys, and magnetic materials such as compounds containing these metals.
Examples of the charge control agent include quaternary ammonium salt compounds, nigrosine compounds, dyes composed of complexes of aluminum, iron, chromium, and triphenylmethane pigments.

  The inorganic particles are added for various purposes, but may be added for adjusting the viscoelasticity of the toner. By adjusting the viscoelasticity, image glossiness and penetration into paper are adjusted. As the inorganic particles, known inorganic particles such as silica particles, titanium oxide particles, alumina particles, cerium oxide particles, or those obtained by hydrophobizing the surface thereof may be used alone or in combination of two or more. From the viewpoint of not impairing transparency such as color developability and OHP permeability, silica particles having a refractive index smaller than that of the binder resin are preferably used. Further, the silica particles may be subjected to various surface treatments, and for example, those subjected to surface treatment with a silane coupling agent, a titanium coupling agent, a silicone oil or the like are preferably used.

Specific examples of the inorganic particles and organic particles, which are external additives externally added to the toner surface, include the following.
Examples of inorganic particles include silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, silica sand, clay, mica, wollastonite, diatomaceous earth, cerium chloride, Examples include Bengala, chromium oxide, cerium oxide, antimony trioxide, magnesium oxide, zirconium oxide, silicon carbide, and silicon nitride. Among these, silica particles and titanium oxide particles are desirable, and particles that have been subjected to hydrophobic treatment are particularly desirable.

Inorganic particles are generally used for the purpose of improving fluidity. The primary particle size of the inorganic particles is desirably in the range of 1 to 200 nm, and the addition amount is desirably in the range of 0.01 to 20 parts by mass with respect to 100 parts by mass of the toner.
Organic particles are generally used for the purpose of improving cleaning properties and transfer properties. Specifically, for example, fluorine resin powders such as polyvinylidene fluoride and polytetrafluoroethylene, fatty acid metal salts such as zinc stearate and calcium stearate. , Polystyrene, polymethyl methacrylate and the like.

[Toner characteristics]
The volume average particle size of the toner is desirably in the range of 4 to 9 μm, more desirably in the range of 4.5 to 8.5 μm, and even more desirably in the range of 5 to 8 μm. When the volume average particle size is smaller than 4 μm, the toner fluidity is lowered, the chargeability of each particle is likely to be lowered, and the charge distribution is widened, so that fogging on the background and toner spillage from the developing device are likely to occur. . On the other hand, if it is smaller than 4 μm, the cleaning property may be extremely difficult. If the volume average particle size is larger than 9 μm, the resolution decreases, so that sufficient image quality cannot be obtained, and it may be difficult to satisfy recent high image quality requirements.
The volume average particle diameter is measured using Multisizer II (manufactured by Beckman-Coulter) with an aperture diameter of 50 μm. In this case, the measurement is performed after the toner is dispersed in an electrolyte aqueous solution (isoton aqueous solution) and dispersed by ultrasonic waves for 30 seconds or more.

The toner preferably has a spherical shape with a shape factor SF1 in the range of 110 to 140. When the shape is spherical in this range, transfer efficiency and image density are improved, and a high-quality image is formed.
The shape factor SF1 is more preferably in the range of 110 to 130.

Here, the shape factor SF1 is obtained by the following equation (12).
SF1 = (ML ² / A) × (π / 4) × 100 (12)
In the above formula (12), ML represents the absolute maximum length of the toner, and A represents the projected area of the toner.

  The SF1 is quantified mainly by analyzing a microscope image or a scanning electron microscope (SEM) image with an image analyzer, and is calculated as follows, for example. That is, an optical microscope image of higher alcohol particles dispersed on the surface of the slide glass is taken into a Luzex image analyzer by a video camera, the maximum length and projected area of 100 particles are obtained, calculated by the above equation (12), and the average Obtained by determining the value.

[Toner Production Method]
The method for producing the toner of the present embodiment is not particularly limited. For example, a resin particle dispersion adjusting step for adjusting the resin particle dispersion in which the first resin particles are dispersed, and a mold release in which the release agent particles are dispersed. A release agent particle dispersion adjusting step for adjusting the agent particle dispersion, and a mixed solution for mixing the resin particle dispersion and the release agent particle dispersion to prepare a mixed solution containing the first resin particles and the release agent particles An adjusting step, an agglomerated particle adjusting step for adjusting the aggregated particles formed by first aggregating the first resin particles with respect to the release agent particles in the mixed solution, and the aggregated particles covered with the second resin particles A resin-coated particle adjusting step for adjusting the resin-coated particles formed in this manner, and a fusion / coalescence method in which the resin-coated particles are heated to a temperature equal to or higher than the glass transition temperature of the first resin particles or the second resin particles. And a process for producing a toner including . The toner manufacturing method may include other steps as necessary.

In the toner manufacturing method, the first resin particles are aggregated earlier than the release agent particles in the aggregated particle adjustment step, and the release agent particles are aggregated later. That is, since the aggregation rate of the first resin particles is relatively faster than the aggregation rate of the release agent particles, the amount of the release agent particles taken in closer to the surface than the inside of the aggregated particles is large. Aggregated particles in which the release agent is unevenly distributed on the surface are formed.
On the other hand, in order for the first resin particles to aggregate before the release agent particles, the release agent particles are more stably dispersed than the first resin particles in the mixed solution. Is desirable. In that case, since the release agent particles have a higher affinity with the solvent, the part where the release agent is exposed also has a higher affinity with the solvent than the other parts on the surface of the aggregated particles. It is thought that 2 resin particles are difficult to coat. Then, in the part where the release agent is exposed in the agglomerated particles, a part that is not covered with the second resin particle is generated, and an opening is formed in the coating resin layer, and a concave release agent exposed part is formed. It is done.

-Particle coagulation value-
In order for the release agent particles to be more stably dispersed than the first resin particles, the coagulation value “Fp (mol / g)” of the first resin particles and the coagulation value “Fw ( mol / g) "preferably satisfies the following formulas (1), (2), and (3).
Formula (1): 1 × 10 ⁻⁵ ≦ Fp ≦ 1 × 10 ⁻¹
Formula (2): 1 × 10 ⁻⁵ ≦ Fw ≦ 1 × 10 ⁻¹
Formula (3): Fp ≦ Fw

  The coagulation value is the minimum amount of magnesium chloride necessary for agglomerating 1 g of particles (first resin particles or release agent particles) in an emulsion having a solid content concentration of 10% by mass, pH 7, and 25 ° C. (Mol / g), which indicates that the larger this is, the more stable the particles are in the dispersion (that is, they are less likely to aggregate).

  When Fp and Fw satisfy the above formulas (1), (2), and (3), the release agent particles are more stably dispersed than the first resin particles in the mixed solution, It is considered that a toner having a concave mold release agent exposed portion on the surface can be obtained. Further, in the resin-coated particle adjustment step, since the release agent particles have a higher affinity with the solvent than the first resin particles, the solvent adhering to the exposed surface of the release agent exposed on the surface of the aggregated particles The presence makes it difficult for the second resin particles to adhere to the exposed surface of the release agent. Therefore, it is considered that a toner having a concave mold release agent exposed portion can be obtained.

If the Fp or Fw is smaller than 1 × 10 ⁻⁵ , it is very difficult to control the particle size of the aggregated particles. On the other hand, if Fp or Fw is larger than 1 × 10 ⁻¹ , it is difficult to control the particle size because aggregation hardly occurs.
Further, when Fw is smaller than Fp, the release agent particles aggregate faster than the first resin particles in the aggregate particle forming step, and therefore, the aggregate particles in which the release agent is unevenly distributed on the surface are hardly formed. Further, the second resin particles are likely to adhere to the release agent exposed surface of the aggregated particles, and it becomes difficult to obtain a toner having a concave release agent exposed portion.

More preferably, the coagulation value Fp of the first resin particles and the coagulation value Fw of the release agent particles satisfy the following formulas (4), (5), and (6).
Formula (4): 5 × 10 ⁻⁵ ≦ Fp ≦ 5 × 10 ⁻³
Formula (5): 5 × 10 ⁻⁴ ≦ Fw ≦ 5 × 10 ⁻²
Formula (6): Fp <Fw

Further, it is more desirable that Fp and Fw satisfy the following formulas (7), (8), and (9).
Formula (7): 1 × 10 ⁻⁴ ≦ Fp ≦ 1 × 10 ⁻³
Formula (8): 1 × 10 ⁻³ ≦ Fw ≦ 1 × 10 ⁻²
Formula (9): Fp <Fw
In addition, when using 2 or more types of binder resin or a release agent particle as a 1st resin particle or a release agent particle, the coagulation value of each resin particle or a release agent particle may be the said range. desirable.

-Measurement method of coagulation value-
The particle coagulation value is measured as follows.
(Preparation of test emulsion)
First, a dispersion (resin particle dispersion or release agent particle dispersion) serving as a sample is prepared at a particle solid content concentration of 12.5 mass%, pH 7, and 25 ° C. Nitric acid and sodium hydroxide are used to adjust the pH.

(Preparation of magnesium chloride aqueous solution)
Magnesium chloride dihydrate is dissolved in ion-exchanged water to prepare magnesium chloride aqueous solution with each concentration (1.0 × 10 ⁻⁵ to 5.0 mol / l).

(Coagulation test)
The dispersion and the magnesium chloride aqueous solution of each concentration are mixed at a mass ratio of 8: 2 (dispersion: magnesium chloride aqueous solution) and stirred so that the total solid content concentration becomes 10% by mass. Next, the particle size of each sample is measured with a particle size distribution analyzer (LS Coulter, manufactured by Coulter, Inc.). The results are graphed with the horizontal axis representing the magnesium chloride concentration and the vertical axis representing the particle size, and the coagulation value (or critical aggregation concentration) is determined from the inflection point of the graph.

Hereinafter, the toner manufacturing method according to the present exemplary embodiment will be described separately for each process.
-Resin particle dispersion adjustment process-
Examples of the adjustment of the resin particle dispersion in which the first resin particles are dispersed include a method of emulsifying by a mechanical shear force and a method of using a phase inversion emulsification method.
In particular, when a polyester resin is used as the binder resin, it is desirable to use a phase inversion emulsification method. By using the phase inversion emulsification method, it is easy to control the coagulation value of the first resin particles in the resin particle dispersion.

(Phase inversion emulsification method)
Examples of the method for adjusting the resin particle dispersion by the phase inversion emulsification method include the following methods. Specifically, for example, the binder resin is dissolved in a mixed solution of an organic solvent (good solvent) and a water-soluble solvent (water-soluble poor solvent), and a neutralizer (for example, ammonia or the like) as necessary. And a dispersion stabilizer are added, and a water-soluble solvent (for example, water) is added dropwise with stirring to obtain emulsified particles. Then, the solvent in the resin particle dispersion is removed to obtain an emulsion (resin particle dispersion). Get. The order of adding the neutralizing agent and the dispersion stabilizer may be changed.

  Examples of the organic solvent (resin dissolving solvent) for dissolving the binder resin include formate esters, acetate esters, butyrate esters, ketones, ethers, benzenes, and halogenated carbons. Specifically, for example, esters such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, t-butyl such as formic acid, acetic acid, butyric acid, acetone, MEK, MPK, MIPK, MBK , Methyl ketones such as MIBK, ethers such as diethyl ether and diisopropyl ether, heterocyclic substituents such as toluene, xylene and benzene, carbon tetrachloride, methylene chloride, 1,2-dichloroethane, 1,1,2-trichloroethane , Trichloroethylene, chloroform, monochlorobenzene, dichloroethylidene, and other halogenated carbons may be used alone or in combination of two or more, but they are low boiling solvents from the standpoint of availability and ease of recovery during solvent removal. Usually, acetates, methyl ketones, and ethers are preferably used. In particular, acetone, methyl ethyl ketone, acetic acid, ethyl acetate, butyl acetate is preferred. Among the organic solvents, from the viewpoint of suppressing the organic solvent from remaining in the resin particles, it is desirable to use one having relatively high volatility.

  As the water-soluble solvent, ion-exchanged water is basically used, but a water-soluble organic solvent may be included so as not to destroy the oil droplets. Examples of the water-soluble organic solvent include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, t-butanol, 1-pentanol, and other short carbon chain alcohols; ethylene glycol monomethyl ether, Examples include ethylene glycol monoalkyl ethers such as ethylene glycol monoethyl ether and ethylene glycol monobutyl ether; ethers, diols, THF, acetone and the like. The mixing ratio of these water-soluble organic solvents to ion-exchanged water is preferably 1% or more and 50% or less, and more preferably 1% or more and 30% or less by mass ratio. In addition, the water-soluble organic solvent may be added to the resin solution and used in addition to the ion-exchanged water to be added. When a water-soluble organic solvent is added, the wettability between the resin and the resin-dissolving solvent is adjusted, and a function of decreasing the liquid viscosity after dissolving the resin is expected.

  If necessary, a dispersion stabilizer may be added to the mixed solution of the resin solution and the water-soluble solvent so that the emulsion stably maintains a dispersed state. Examples of the dispersion stabilizer include those that form a hydrophilic colloid in a water-soluble solvent. For example, cellulose derivatives such as hydroxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose; polyvinyl alcohol, polyvinyl pyrrolidone, polyacrylamide, Examples thereof include synthetic polymers such as polyacrylate and polymethacrylate, and dispersion stabilizers such as gelatin, gum arabic and agar. As the dispersion stabilizer, solid powders such as silica, titanium oxide, alumina, tricalcium phosphate, calcium carbonate, calcium sulfate, and barium carbonate are also used. These dispersion stabilizers are added so that the concentration in the water-soluble solvent is desirably 0% by mass to 20% by mass, and more desirably 0% by mass to 10% by mass.

  A surfactant is also used as the dispersion stabilizer. Examples of the surfactant are the same as those used in the colorant dispersion described later. For example, in addition to natural surfactant components such as saponins, cationic surfactants such as alkylamine hydrochlorides / acetates, quaternary ammonium salts, glycerols, fatty acid soaps, sulfates, alkylnaphthalene sulfonates, sulfones Anionic surfactants such as acid salts, phosphoric acid, phosphate esters, sulfosuccinates and the like can be mentioned, and anionic surfactants and nonionic surfactants are preferably used. In order to adjust the pH of the emulsion, a neutralizing agent may be added. As the neutralizing agent, nitric acid, hydrochloric acid, sodium hydroxide, ammonia and other general acids and alkalis are used, but sodium hydroxide is used from the viewpoint of easy adjustment of the coagulation value of the resin particle dispersion. Is desirable.

  As a method for removing the organic solvent from the emulsion, a method in which the organic solvent is volatilized at room temperature (25 ° C.) or under heating, and a method in which reduced pressure is combined with this are preferably used.

(Method of emulsification by mechanical shearing force)
Examples of the method of emulsifying with a mechanical shear force include a method in which a shear force is applied to a solution obtained by mixing an aqueous medium and a binder resin with a disperser. At that time, it is desirable to form particles by heating to lower the viscosity of the resin component. A dispersant may be used for stabilizing the dispersed resin particles.

Examples of the aqueous medium include water such as distilled water and ion-exchanged water; alcohols; and the like.
Examples of the dispersant used in the emulsification step include water-soluble polymers such as polyvinyl alcohol, methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, sodium polyacrylate, and sodium polymethacrylate; sodium dodecylbenzenesulfonate. Anionic surfactants such as sodium octadecyl sulfate, sodium oleate, sodium laurate, potassium stearate, cationic surfactants such as laurylamine acetate, stearylamine acetate, lauryltrimethylammonium chloride, lauryldimethylamine oxide, etc. Zwitterionic surfactant, polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene Surfactants such as nonionic surfactants down alkyl amine; and the like are; tricalcium phosphate, aluminum hydroxide, calcium sulfate, calcium carbonate, inorganic salts such as barium carbonate.

(Characteristics of resin particle dispersion)
The coagulation value of the first resin particles in the resin particle dispersion preferably satisfies the above formulas (1) and (3), more preferably satisfies the above formulas (4) and (6), and the above formula ( It is further desirable to satisfy 7) and (9).
When using a polyester resin as the binder resin and adjusting the resin particle dispersion by the phase inversion emulsification method, as a method for controlling the coagulation value of the first resin particles, for example, the amount of sodium hydroxide used as a neutralizing agent The method of controlling by changing is mentioned. The amount of sodium hydroxide used as the neutralizing agent is preferably 1 × 10 ⁻³ parts by mass to 6 × 10 ⁻³ parts by mass and more preferably 2 × 10 ⁻³ parts by mass with ^respect to 100 parts by mass of the binder resin. 5 × 10 ⁻³ parts by mass or less is more preferable, and 3 × 10 ⁻³ parts by mass or more and 4 × 10 ⁻³ parts by mass or less are more preferable.
In addition to the resin particle dispersion in which the first resin particles are dispersed, other resin particle dispersions in which the third resin particles are dispersed are used in combination (for example, non-crystalline as the first resin particles). When resin resin particles are used and crystalline resin resin particles are used as the third resin particles), the coagulation value of the third resin particles is preferably within the above range.

  The content of the resin particles contained in the resin particle dispersion is preferably in the range of 10 to 50% by mass, more preferably in the range of 20 to 40% by mass. When the content is less than 10% by mass, the particle size distribution is widened and the toner characteristics may be deteriorated. On the other hand, if it exceeds 50% by mass, uniform stirring becomes difficult, and it may be difficult to obtain a toner having a narrow particle size distribution and uniform characteristics.

  As the size of the resin particles, the average particle size (volume average particle size) is preferably in the range of 0.08 to 0.8 μm, more preferably 0.09 to 0.6 μm, and 0.10 to 0.5 μm. More desirable.

  The volume average particle diameter of the resin particles is measured using a laser diffraction particle size distribution measuring device (LA-700: manufactured by Horiba, Ltd.). As a measuring method, the sample in the state of dispersion is adjusted so as to have a solid content of 2 g, and ion exchange water is added thereto to make 40 ml. This is put into the cell, waits for 2 minutes, and is measured when the concentration in the cell becomes stable. The obtained volume average particle diameter for each channel is accumulated from the smaller volume average particle diameter, and the place where the accumulation reaches 50% is defined as the volume average particle diameter. The volume average particle diameters of the release agent particles and the colorant particles are also measured by the same method.

-Release agent particle dispersion adjustment process-
The release agent particle dispersion includes, for example, an ionic surfactant, a polymer electrolyte such as a polymer acid or a polymer base, and the above release agent dispersed in water, heated to a temperature higher than the melting temperature, The release agent particle dispersion containing the release agent particles is prepared by adjusting the particles by using a homogenizer or a pressure discharge type disperser.

  The volume average particle size of the release agent particles in the release agent particle dispersion is 1 μm or less in order to easily adjust the volume average particle size and particle size distribution of the toner particles to desired values. Desirably, it is more desirably 100 nm or more and 300 nm or less.

Further, a surfactant may be used for the purpose of stabilizing the dispersion of each dispersion.
Examples of the surfactant include anionic surfactants such as sulfate, sulfonate, phosphate, and soap; cationic surfactants such as amine salt type and quaternary ammonium salt type; polyethylene glycol And nonionic surfactants such as polyphenols, alkylphenol ethylene oxide adducts, and polyhydric alcohols. Among these, ionic surfactants are desirable, anionic surfactants and cationic surfactants are more desirable, and anionic surfactants are more desirable. The said surfactant may be used individually by 1 type, and may be used in combination of 2 or more type.

  Specific examples of the anionic surfactant include, for example, fatty acid soaps such as potassium laurate, sodium oleate and sodium castor oil; sulfates such as octyl sulfate, lauryl sulfate, lauryl ether sulfate and nonylphenyl ether sulfate; Sodium alkylnaphthalene sulfonate such as lauryl sulfonate, dodecyl benzene sulfonate, triisopropyl naphthalene sulfonate, dibutyl naphthalene sulfonate; naphthalene sulfonate formalin condensate, monooctyl sulfosuccinate, dioctyl sulfosuccinate, lauric acid amide sulfonate, oleic acid amide sulfonate, etc. Sulfonates: lauryl phosphate, isopropyl phosphate, nonylphenyl Phosphoric acid esters such as chromatography ether phosphates; dialkyl sulfosuccinate salts such as sodium dioctyl sulfosuccinate; sulfosuccinate salts such as sulfosuccinate lauryl disodium; and the like.

  Specific examples of the cationic surfactant include amine salts such as laurylamine hydrochloride, stearylamine hydrochloride, oleylamine acetate, stearylamine acetate, stearylaminopropylamine acetate; lauryltrimethylammonium chloride, dilauryl Dimethylammonium chloride, distearyldimethylammonium chloride, distearyldimethylammonium chloride, lauryldihydroxyethylmethylammonium chloride, oleylbispolyoxyethylenemethylammonium chloride, lauroylaminopropyldimethylethylammonium ethosulphate, lauroylaminopropyldimethylhydroxyethylammonium perchlorate , Alkylbenzene trimethyl ammonium chlora De, quaternary ammonium salts such as alkyl trimethyl ammonium chloride; and the like.

  Specific examples of the nonionic surfactant include alkyl ethers such as polyoxyethylene octyl ether, polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether; polyoxyethylene octyl phenyl ether, Alkylphenyl ethers such as polyoxyethylene nonylphenyl ether; alkyl esters such as polyoxyethylene laurate, polyoxyethylene stearate, polyoxyethylene oleate; polyoxyethylene lauryl amino ether, polyoxyethylene stearyl amino ether, poly Alkylamines such as oxyethylene oleyl amino ether, polyoxyethylene soybean amino ether, polyoxyethylene beef tallow amino ether; Alkylamides such as reoxyethylene lauric acid amide, polyoxyethylene stearic acid amide, polyoxyethylene oleic acid amide; vegetable oil ethers such as polyoxyethylene castor oil ether, polyoxyethylene rapeseed oil ether; lauric acid diethanolamide, Alkanolamides such as stearic acid diethanolamide and oleic acid diethanolamide; sorbitan esters such as polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmiate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan monooleate Ethers; and the like.

The coagulation value of the release agent particles in the release agent particle dispersion preferably satisfies the above formulas (2) and (3), more preferably satisfies the above formulas (5) and (6). It is further desirable to satisfy (8) and (9).
Examples of the method for controlling the coagulation value of the release agent particles include a method for controlling by changing the amount of the surfactant used in the release agent particle dispersion, and a method for controlling by changing the dispersion treatment time. It is done.

The preferable amount of the surfactant used in the release agent particle dispersion varies depending on the type of the surfactant. For example, when lauryl sulfonate is used as the surfactant, it is preferably 3.0 parts by mass or more and 8.0 parts by mass or less, and more preferably 4.0 parts by mass or more and 7.0 parts by mass or less with respect to 100 parts by mass of the release agent. 5.0 parts by mass or more and 6.0 parts by mass or less are more preferable. For example, when dodecylbenzenesulfonate is used as the surfactant, it is preferably 0.1 parts by weight or more and 3.0 parts by weight or less, and 0.5 parts by weight or more and 2.0 parts by weight or less with respect to 100 parts by weight of the release agent. Is more preferable, and 1.0 mass part or more and 1.5 mass parts or less are still more preferable.
The dispersion treatment time is preferably from 50 minutes to 800 minutes, more preferably from 150 minutes to 600 minutes, and even more preferably from 300 minutes to 400 minutes.

-Other dispersion adjustment processes-
When the toner contains a colorant, the method for producing the toner may include a step of separately adjusting the colorant particle dispersion. The colorant particle dispersion is prepared by a known method. For dispersion of the colorant particles, for example, a rotary shear type homogenizer, a media type disperser such as a ball mill, a sand mill, or an attritor, a high-pressure opposed collision type dispersion is used. A machine or the like is preferably used.
Further, a polar ionic surfactant is used and dispersed in an aqueous solvent using a homogenizer as described above to produce a colorant particle dispersion.

  The volume average particle diameter of the colorant particles in the colorant particle dispersion is desirably 1 μm or less in order to facilitate adjusting the volume average particle diameter and particle size distribution of the toner particles to desired values. It is more desirable that the thickness be 100 nm or more and 300 nm or less.

-Mixed solution adjustment process-
In the mixed solution adjustment step, the resin particle dispersion adjusted in the dispersion adjustment step, the release agent particle dispersion, and, if necessary, other dispersions such as the colorant particle dispersion are mixed and mixed. Adjust the solution.

-Aggregated particle adjustment process-
In the aggregated particle adjusting step, the mixed solution is heated to form aggregated particles in which particles in the mixed solution are aggregated. At this time, as described above, since the release agent particles have a higher affinity with the solvent and are stably dispersed in the mixed solution than the first resin particles, the first resin than the release agent particles. The particles are aggregated first, and the release agent particles are aggregated later than the first resin particles. Therefore, in the formed aggregated particles, the release agent is unevenly distributed on the surface.
In addition, it is desirable to implement heating below the glass transition temperature of the first resin particles. Aggregated particles are formed, for example, by acidifying the pH of the mixed solution while stirring with a rotary shearing homogenizer or the like. The pH is preferably in the range of 2 to 7, more preferably in the range of 2.2 to 6, and even more preferably in the range of 2.4 to 5. At this time, it is also effective to use a flocculant.

  As the flocculant to be used, a surfactant having a reverse polarity to the surfactant used for the dispersant, an inorganic metal salt, and a divalent or higher metal complex are preferably used. In particular, the use of a metal complex is particularly desirable because the amount of the surfactant used is reduced and the charging characteristics are improved.

  Examples of the inorganic metal salt include metal salts such as calcium chloride, calcium nitrate, barium chloride, magnesium chloride, zinc chloride, aluminum chloride, and aluminum sulfate, and polyaluminum chloride, polyaluminum hydroxide, and calcium polysulfide. Examples thereof include inorganic metal salt polymers. Of these, aluminum salts and polymers thereof are particularly preferred. In order to obtain a sharper particle size distribution, the valence of the inorganic metal salt is bivalent than monovalent, trivalent than bivalent, trivalent than trivalent, and tetravalent than trivalent. The inorganic metal salt polymer is more suitable.

  Examples of the metal complex having a valence of 2 or more include magnesium chloride, calcium chloride, zinc chloride, barium chloride, aluminum sulfate, polyaluminum chloride, and the like. Aluminum and polyaluminum chloride are preferable, and polyaluminum chloride is more preferable.

Among the above-mentioned flocculants, in the case where the first resin particles are aggregated first and the release agent particles are aggregated later as in this embodiment, two or more kinds of flocculants may be used in combination. desirable. Examples of the combination of two or more kinds of flocculants include magnesium chloride and polyaluminum chloride.
Moreover, although the addition amount of a flocculant changes with kinds of flocculant to be used, the total addition amount of the flocculant to be used is 0.1 to 3.0 mass parts with respect to 100 mass parts of binder resin, for example. Preferably, 0.5 parts by mass or more and 2.0 parts by mass or less are more preferable, and 1.0 part by mass or more and 1.5 parts by mass or less are more preferable.

-Resin coated particle adjustment process-
In the resin-coated particle adjustment step, the resin-coated layer is formed by attaching the second resin particles to the surface of the above-described aggregated particles (core particles) to adjust the resin-coated particles. Specifically, it is carried out by additionally adding a dispersion liquid containing the second resin particles to the aggregate particle dispersion liquid in which the aggregate particles are dispersed. The second resin particles may be the same as or different from the first resin particles.

-Fusion / unification process-
In the coalescence and coalescence process, the agglomeration is stopped by raising the pH of the suspension of the resin-coated particles to a range of 3 to 9 under stirring conditions, and heated above the glass transition temperature of the second resin particles. To fuse and coalesce the resin-coated particles. The heating time may be as long as fusion is performed, and may be performed for about 0.5 to 10 hours.

  Cool after fusion to obtain fused particles. Further, the fused particles obtained by fusing in the cooling step form toner particles through a solid-liquid separation step such as filtration and, if necessary, a washing step and a drying step.

-External addition process-
If necessary, an external additive such as a fluidizing agent or an auxiliary agent may be added to the surface of the toner particles. Examples of the external additive include known inorganic particles such as silica particles, titanium oxide particles, alumina particles, cerium oxide particles, and carbon black whose surfaces have been hydrophobized, and polymer particles such as polycarbonate, polymethyl methacrylate, and silicone resin. Among these, at least two kinds of external additives are used, and at least one of the external additives is an average primary particle in the range of 30 nm to 200 nm, and further in the range of 30 nm to 180 nm. It is desirable to have a diameter.

  If the average primary particle diameter of the external additive is smaller than 30 nm, the initial toner fluidity is good, but the non-electrostatic adhesion force between the toner and the photoreceptor is not reduced, and the transfer efficiency is lowered. In some cases, the image may be lost or the uniformity of the image may be deteriorated (density variation may be increased). Further, due to stress in the developing device over time, the particles are embedded in the toner surface and the chargeability changes, which may cause problems such as a decrease in copy density and fogging on the background. When the average primary particle size is larger than 200 nm, it is likely to be detached from the toner surface and may cause deterioration of fluidity.

<Electrostatic latent image developer>
The toner for developing an electrostatic latent image of this embodiment is used as it is as a one-component developer or as a two-component developer. When used as a two-component developer, it is used by mixing with a carrier.

  The carrier that can be used in the two-component developer is not particularly limited, and a known carrier is used. Examples thereof include magnetic metals such as iron oxide, nickel and cobalt, magnetic oxides such as ferrite and magnetite, resin-coated carriers having a resin coating layer on the surface of the core material, and magnetic dispersion carriers. Further, a resin-dispersed carrier in which a conductive material or the like is dispersed in a matrix resin may be used.

  Coating resins and matrix resins used for carriers include polyethylene, polypropylene, polystyrene, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl ether, polyvinyl ketone, vinyl chloride-vinyl acetate copolymer, styrene-acrylic. Examples include, but are not limited to, an acid copolymer, a straight silicone resin containing an organosiloxane bond or a modified product thereof, a fluororesin, a polyester, a polycarbonate, a phenol resin, and an epoxy resin.

  Examples of the conductive material include metals such as gold, silver and copper, carbon black, titanium oxide, zinc oxide, barium sulfate, aluminum borate, potassium titanate, tin oxide, and carbon black, but are not limited thereto. It is not something.

  Examples of the core material of the carrier include magnetic metals such as iron, nickel, and cobalt, magnetic oxides such as ferrite and magnetite, and glass beads. However, in order to use the carrier for the magnetic brush method, it is a magnetic material. It is desirable. The volume average particle size of the core material of the carrier is generally in the range of 10 to 500 μm, and preferably in the range of 30 to 100 μm.

  In order to coat the surface of the core material of the carrier with a resin, there may be mentioned a method of coating with a coating layer forming solution prepared by dissolving the coating resin and, if necessary, various additives in an appropriate solvent. The solvent is not particularly limited, and may be selected in consideration of the coating resin to be used, coating suitability, and the like.

  Specific resin coating methods include an immersion method in which the carrier core material is immersed in the coating layer forming solution, a spray method in which the coating layer forming solution is sprayed onto the surface of the carrier core material, and the carrier core material is fluidized air. A fluidized bed method in which the coating layer forming solution is sprayed in a state of being suspended by the above, a kneader coater method in which the carrier core material and the coating layer forming solution are mixed in a kneader coater, and the solvent is removed.

  The volume average particle size distribution index GSDv of the carrier obtained as described above is preferably in the range of 1.15 to 1.35, and more preferably in the range of 1.15 to 1.25.

The GSDv value of the carrier was measured and calculated as follows. First, for the carrier size distribution (channel) measured using Multisizer II (manufactured by Beckman-Coulter) as a measuring instrument, the cumulative distribution is drawn from the small diameter side for each carrier volume. In addition, the particle size that is cumulative 16% is defined as the volume average particle size D16v, and the particle size that is cumulative 84% is defined as the volume average particle size D84v. Using these, the volume average particle size distribution index GSDv is defined as (D84v / D16v) ^1/2 .

  The mixing ratio (mass ratio) of the toner of the present embodiment and the carrier in the two-component developer is preferably in the range of toner: carrier = 1: 100 to 30: 100, and about 3: 100 to 20: 100. Range is more desirable.

<Image forming apparatus>
Next, an image forming apparatus using the electrostatic latent image developing toner of this embodiment will be described.
The image forming apparatus according to the present embodiment develops a latent image holding member, an electrostatic latent image forming unit that forms an electrostatic latent image on the surface of the latent image holding member, and the electrostatic latent image as a toner image using a developer. A developing unit; a transfer unit that transfers the toner image formed on the latent image holding member onto the transfer member; and a fixing unit that fixes the toner image transferred onto the transfer member. The electrostatic latent image developer of this embodiment is used as the agent.

In this image forming apparatus, for example, the part including the developing unit may have a cartridge structure (process cartridge) that is not detachable from the main body of the image forming apparatus. As the process cartridge, a developer holder And the process cartridge of this embodiment that contains the electrostatic latent image developer of this embodiment is preferably used.
Hereinafter, although an example of the image forming apparatus of this embodiment is shown, it is not necessarily limited to this. The main parts shown in the figure will be described, and the description of the other parts will be omitted.

  FIG. 3 is a schematic configuration diagram illustrating a four-tandem full-color image forming apparatus. The image forming apparatus shown in FIG. 3 is the first electrophotographic system that outputs yellow (Y), magenta (M), cyan (C), and black (K) images based on color-separated image data. Fourth image forming units 10Y, 10M, 10C, and 10K (image forming means) are provided. These image forming units (hereinafter simply referred to as “units”) 10Y, 10M, 10C, and 10K are juxtaposed at a predetermined distance in the horizontal direction. The units 10Y, 10M, 10C, and 10K may be process cartridges that are detachable from the main body of the image forming apparatus.

Above each of the units 10Y, 10M, 10C, and 10K, an intermediate transfer belt 20 as an intermediate transfer member is extended through each unit.
The intermediate transfer belt 20 is provided by being wound around a driving roller 22 and a support roller 24 that are in contact with the inner surface of the intermediate transfer belt 20 that are spaced apart from each other from the left to the right in the drawing. It is designed to travel in the direction toward 10K.
The support roller 24 is urged away from the drive roller 22 by a spring or the like (not shown), and a predetermined tension is applied to the intermediate transfer belt 20 wound around the support roller 24. Further, an intermediate transfer body cleaning device 30 is provided on the side surface of the intermediate transfer belt 20 so as to face the driving roller 22, and a secondary transfer roller 26 is provided so as to face the support roller 24.
Further, each of the developing devices 4Y, 4M, 4C, and 4K (developing means) of each unit 10Y, 10M, 10C, and 10K includes yellow, magenta, cyan, and black contained in the toner cartridges 8Y, 8M, 8C, and 8K. The four colors of toner are supplied.

  Since the first to fourth units 10Y, 10M, 10C, and 10K have the same configuration, the first unit that forms a yellow image disposed on the upstream side in the intermediate transfer belt traveling direction here. 10Y will be described as a representative. Note that the second to fourth units are given the same reference numerals with magenta (M), cyan (C), and black (K) instead of yellow (Y) in the same parts as the first unit 10Y. Description of 10M, 10C, 10K is omitted.

The first unit 10Y has a photoreceptor 1Y (latent image holder) that acts as an image holder. Around the photoreceptor 1Y, an electrostatic latent image is formed by exposing the surface of the photoreceptor 1Y to a predetermined potential with a charging device 2Y and exposing the charged surface with a laser beam 3Y based on the color-separated image signal. An exposure device 3 (electrostatic latent image forming means) for developing, a developing device 4Y (developing means) for supplying the electrostatic latent image with charged toner and developing the electrostatic latent image, and the developed toner image on the intermediate transfer belt 20 A primary transfer roller 5Y for transferring the toner to the surface of the photosensitive member 1Y, and a photosensitive member cleaning device 6Y (cleaning means) for removing the toner remaining on the surface of the photosensitive member 1Y after the primary transfer are sequentially disposed.
The primary transfer roller 5Y is disposed inside the intermediate transfer belt 20, and is provided at a position facing the photoreceptor 1Y. Further, a bias power source (not shown) for applying a primary transfer bias is connected to each of the primary transfer rollers 5Y, 5M, 5C, and 5K. Each bias power source varies the transfer bias applied to each primary transfer roller under the control of a control unit (not shown).

Hereinafter, an operation of forming a yellow image in the first unit 10Y will be described. First, prior to the operation, the surface of the photoreceptor 1Y is charged to a potential of about −600V to −800V by the charging device 2Y.
The photoreceptor 1Y is formed by laminating a photosensitive layer on a conductive substrate (volume resistivity at 20 ° C .: 1 × 10 ⁻⁶ Ωcm or less). This photosensitive layer usually has a high resistance (a resistance equivalent to that of a general resin), but has a property that the specific resistance of the portion irradiated with the laser beam changes when irradiated with the laser beam 3Y. Therefore, a laser beam 3Y is output to the surface of the charged photoreceptor 1Y via the exposure device 3 in accordance with yellow image data sent from a control unit (not shown). The laser beam 3Y is applied to the photosensitive layer on the surface of the photoreceptor 1Y, whereby an electrostatic latent image of a yellow print pattern is formed on the surface of the photoreceptor 1Y.

The electrostatic latent image is an image formed on the surface of the photoreceptor 1Y by charging, and the specific resistance of the irradiated portion of the photosensitive layer is lowered by the laser beam 3Y, and the charged charge on the surface of the photoreceptor 1Y is reduced. On the other hand, it is a so-called negative latent image formed by the charge remaining in the portion not irradiated with the laser beam 3Y.
The electrostatic latent image formed on the photoreceptor 1Y in this way is rotated to a predetermined development position as the photoreceptor 1Y travels. Then, at this development position, the electrostatic latent image on the photoreceptor 1Y is converted into a visible image (developed image) by the developing device 4Y.

  For example, yellow toner containing a yellow colorant is accommodated in the developing device 4Y. The yellow toner is triboelectrically charged by being agitated inside the developing device 4Y, and has a charge of the same polarity (negative polarity) as the charged charge on the photoreceptor 1Y, and a developer roll (developer holder). Is held on. As the surface of the photoreceptor 1Y passes through the developing device 4Y, the yellow toner is electrostatically attached to the latent image portion on the surface of the photoreceptor 1Y, and the latent image is developed with the yellow toner. . The photoreceptor 1Y on which the yellow toner image is formed continues to run at a predetermined speed, and the toner image developed on the photoreceptor 1Y is conveyed to a predetermined primary transfer position.

When the yellow toner image on the photoreceptor 1Y is conveyed to the primary transfer, a predetermined primary transfer bias is applied to the primary transfer roller 5Y, and the electrostatic force directed from the photoreceptor 1Y to the primary transfer roller 5Y generates a toner image. The toner image on the photoreceptor 1 </ b> Y is transferred onto the intermediate transfer belt 20. The transfer bias applied at this time is a (+) polarity opposite to the polarity (−) of the toner, and is controlled to about +10 μA by the control unit (not shown) in the first unit 10Y, for example.
On the other hand, the toner remaining on the photoreceptor 1Y is removed and collected by the cleaning device 6Y.

Further, the primary transfer bias applied to the primary transfer rollers 5M, 5C, and 5K after the second unit 10M is also controlled according to the first unit.
Thus, the intermediate transfer belt 20 onto which the yellow toner image has been transferred by the first unit 10Y is sequentially conveyed through the second to fourth units 10M, 10C, and 10K, and the toner images of the respective colors are superimposed and transferred in a multiple manner.

  The intermediate transfer belt 20 onto which the four color toner images have been transferred in multiple ways through the first to fourth units is disposed on the intermediate transfer belt 20, the support roller 24 in contact with the inner surface of the intermediate transfer belt 20, and the image holding surface side of the intermediate transfer belt 20. The secondary transfer roller 26 (transfer means) configured to reach the secondary transfer portion. On the other hand, the recording paper P (transfer object) is fed at a predetermined timing to a gap where the secondary transfer roller 26 and the intermediate transfer belt 20 are pressed against each other via a supply mechanism, and a predetermined secondary transfer bias is supported. Applied to the roller 24. The transfer bias applied at this time is a (−) polarity that is the same polarity as the polarity (−) of the toner, and an electrostatic force from the intermediate transfer belt 20 toward the recording paper P is applied to the toner image, so The toner image is transferred onto the recording paper P. The secondary transfer bias at this time is determined according to the resistance detected by a resistance detection means (not shown) for detecting the resistance of the secondary transfer portion, and is voltage-controlled.

Thereafter, the recording paper P is fed into the fixing device 28 (fixing means), and the toner image is heated, and the toner images superimposed in color are melted and fixed on the recording paper P. Then, the recording paper P on which the toner image is fixed by the fixing device 28 is sent to the decurler member 32, and the curling of the recording paper P due to heat is extended. After the fixing of the color image is completed and the curl is extended by the decurler member 32, the recording paper P is carried out toward the discharge unit, and a series of color image forming operations is completed.
The image forming apparatus exemplified above is configured to transfer the toner image onto the recording paper P via the intermediate transfer belt 20, but the present invention is not limited to this configuration, and the toner image is directly transferred from the photoconductor. It may be a structure that is transferred to a recording sheet.

<Process cartridge, toner cartridge>
FIG. 4 is a schematic configuration diagram showing a preferred example of a process cartridge containing the electrostatic latent image developer according to the present embodiment. The process cartridge 200 includes, together with the photosensitive member 107, a charging roller 108, a developing device 111 including a developer holding member 111A, a photosensitive member cleaning device (cleaning unit) 113, an opening 118 for exposure, and for static elimination exposure. Are combined and integrated using the mounting rail 116.
The process cartridge 200 includes an image forming unit that includes a transfer device 112 that transfers an image onto the recording paper 300, a fixing device 115 that fixes the image transferred onto the recording paper 300, and other components (not shown). The apparatus is detachable from the apparatus main body, and constitutes the image forming apparatus together with the image forming apparatus main body.

  The process cartridge shown in FIG. 4 includes a charging roller 108, a developing device 111, a cleaning device (cleaning means) 113, an opening 118 for exposure, and an opening 117 for static elimination exposure. If the agent holding body 111A is provided, other devices are selectively combined.

  Next, the toner cartridge of this embodiment will be described. The toner cartridge is a toner cartridge that is detachably attached to the image forming apparatus and stores at least toner to be supplied to the developing means provided in the image forming apparatus. The toner according to the exemplary embodiment. It should be noted that at least the toner may be accommodated in the toner cartridge of the present embodiment, and for example, a developer may be accommodated depending on the mechanism of the image forming apparatus.

  The image forming apparatus shown in FIG. 3 is an image forming apparatus having a configuration in which the toner cartridges 8Y, 8M, 8C, and 8K are attached and detached. The developing devices 4Y, 4M, 4C, and 4K each have a developing device (color). And a toner supply pipe (not shown). Further, when the amount of toner stored in the toner cartridge is low, this toner cartridge may be replaced.

  Hereinafter, although an example and a comparative example are given and the present invention is explained more concretely in detail, the present invention is not limited to the following examples. In the following description, “part” represents “part by mass” and “%” represents “% by mass” unless otherwise specified.

<Measurement method>
[Measurement of volume average particle diameter of toner]
The volume average particle diameter of the toner was measured using Multisizer II (manufactured by Beckman Coulter, Inc.) with an aperture diameter of 50 μm. At this time, the measurement was performed after the toner was dispersed in an electrolyte aqueous solution (Isoton aqueous solution) and dispersed by ultrasonic waves for 30 seconds or more.

[Measurement of shape factor SF1]
The toner shape factor SF1 is quantified by analyzing a microscope image or a scanning electron microscope (SEM) image using an image analyzer. Specifically, an optical microscope image of the higher alcohol particles dispersed on the surface of the slide glass is taken into a Luzex image analyzer through a video camera, and the maximum length and projected area of 100 particles are obtained. Obtained by determining the value.
Formula: SF1 = (ML ² / A) × (π / 4) × 100
In the above formula, ML represents the absolute maximum length of the toner particles, and A represents the projected area of the toner particles.

[Measurement of glass transition temperature and melting temperature]
The glass transition temperature and the melting temperature were measured according to JIS 7121-1987 using a differential scanning calorimeter (manufactured by Mac Science: DSC3110, thermal analysis system 001). The melting temperature of the mixture of indium and zinc was used for temperature correction of the detection part of this device, and the heat of melting of indium was used for correction of the amount of heat. The sample was put in an aluminum pan, an aluminum pan containing the sample and an empty aluminum pan for control were set, and the measurement was performed at a heating rate of 10 ° C./min.
About melting temperature, it was set as melting temperature with the temperature of the peak of the largest endothermic peak among the endothermic peaks of the DSC curve obtained by measurement.
Moreover, about the glass transition temperature, it was set as the glass transition temperature with the temperature of the intersection of the extended line of the base line in the endothermic part of the DSC curve obtained by the measurement, and the rising line.

[Measurement method of acid value]
2 g of a sample was weighed and dissolved in 160 ml of acetone-toluene, or a sample with insufficient solubility was heated and dissolved, and then measured by the potentiometric titration method of JIS K0070-1992.

[Method for measuring weight average molecular weight]
The weight average molecular weight is measured by gel permeation chromatography (GPC). The molecular weight measurement by GPC was performed with a THF solvent using a Tosoh column / TSKgel Super HM-M (15 cm) using a Tosoh GPC / HLC-8120 as a measuring device. The weight average molecular weight is calculated from the measurement result using a molecular weight calibration curve prepared with a monodisperse polystyrene standard sample.

[Measuring method of average particle diameter of resin particles, release agent particles, colorant particles, and inorganic particles]
The volume average particle diameter of the particles was measured using a laser diffraction particle size distribution measuring apparatus (LA-700: manufactured by Horiba Seisakusho).

  As a measuring method, the sample in the state of dispersion is adjusted so as to have a solid content of 2 g, and ion exchange water is added thereto to make 40 ml. This was added to the cell until the appropriate concentration was reached, waited for 2 minutes, and measured when the concentration in the cell became stable.

  The obtained volume average particle diameter for each channel was accumulated from the smaller volume average particle diameter, and the volume average particle diameter was determined to be 50%.

  When measuring powder, 2 g of a measurement sample is added to 50 ml of a 5% aqueous solution of a surfactant (sodium dodecylbenzenesulfonate), and dispersed for 2 minutes with an ultrasonic disperser (1,000 Hz). A sample was prepared and measured by the same method as the above-mentioned dispersion.

[Measurement method of particle coagulation value]
-Preparation of test emulsion-
First, an emulsion (resin particle dispersion) serving as a sample is prepared at a solid content concentration of 12.5% by mass, pH 7, and 25 ° C. Nitric acid and sodium hydroxide were used for pH adjustment.

-Preparation of magnesium chloride aqueous solution-
Magnesium chloride dihydrate was dissolved in ion-exchanged water to prepare magnesium chloride aqueous solutions of various concentrations (1.0 × 10 ⁻⁵ to 5.0 mol / l).

-Coagulation test-
The emulsion, the magnesium chloride aqueous solution of each concentration, and a mass ratio of 8: 2 (emulsion: magnesium chloride aqueous solution) were mixed and stirred so that the total solid content was 10% by mass. Subsequently, the particle size of each sample was measured by a particle size distribution measuring device (LS Coulter, manufactured by Coulter). The results were graphed with the horizontal axis representing the magnesium chloride concentration and the vertical axis representing the particle size, and the inflection point of the graph was the coagulation value.

<Synthesis of each resin>
[Amorphous polyester resin (1)]
In a heat-dried two-necked flask, 194 parts of dimethyl terephthalate, 90 parts of 1,3-butanediol, and 0.3 part of dibutyltin oxide as a catalyst were placed, and then the air in the container was removed by decompression. The atmosphere was inert with nitrogen gas, and stirring was performed at 180 rpm with mechanical stirring for 5 hours. Thereafter, the temperature was gradually raised to 230 ° C. under reduced pressure, and the mixture was stirred for 2 hours. When it became viscous, it was air-cooled, the reaction was stopped, and amorphous polyester resin (1) (derived from aromatic dicarboxylic acid) 240 parts of an amorphous polyester resin comprising an acid-derived constituent component having a constituent content of 100 constituent% and an alcohol-derived constituent component having an aliphatic diol-derived constituent component content of 100 constituent mole%. Synthesized.

  The weight average molecular weight (Mw) of the obtained amorphous polyester resin (1) was 9500 and the number average molecular weight (Mn) was 4200 by molecular weight measurement (polystyrene conversion) by gel permeation chromatography. Further, when the DSC spectrum of the non-crystalline polyester resin (1) was measured using the above-mentioned differential scanning calorimeter (DSC), no clear peak was shown, and a stepwise endothermic change was observed. The glass transition temperature was 53 ° C.

<Adjustment of each dispersion>
[Amorphous polyester resin particle dispersion (1)]
160 parts of amorphous polyester resin (1), 233 parts of ethyl acetate, and 0.5 part of aqueous sodium hydroxide (0.3N) were placed in a 500 ml separable flask and heated at 70 ° C. A resin mixture was prepared by stirring with a motor (Shinto Kagaku Co., Ltd.). While further stirring this resin mixture, 373 parts of ion-exchanged water was gradually added, phase-inversion emulsified, and the solvent was removed to obtain an amorphous polyester resin particle dispersion (1).
The volume average particle diameter of the resin particles in the amorphous polyester resin particle dispersion (1) was 200 nm, and the solid content was 30% by mass. Moreover, it was 5.0 * 10 < ^-4 > (mol / g) when the coagulation value of the resin particle in the said amorphous polyester resin particle dispersion liquid (1) was measured.

[Non-crystalline polyester resin particle dispersions (2) to (5)]
Amorphous polyester resin particle dispersion (2) In the same manner as the amorphous polyester resin particle dispersion (1) except that the amount of sodium hydroxide aqueous solution (0.3N) added is as shown in Table 1 below. From this, an amorphous polyester resin particle dispersion (5) was prepared. The volume average particle diameter of the resin particles in the dispersion was 200 nm, and the solid content was 30% by mass. Table 1 shows the coagulation values of the resin particles in the dispersion.

[Release Agent Particle Dispersion (1)]
Paraffin wax (Nippon Seiwa Co., Ltd., HNP-9, melting temperature: 75 ° C.): 50 parts Anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd., Neogen RK): 1.2 parts Ion-exchanged water: 200 parts or more are mixed, heated to 95 ° C. and dispersed using a homogenizer (Ultra Tlux T50, manufactured by IKA), and then subjected to a dispersion treatment for 360 minutes using a Menton Gorin high-pressure homogenizer (Gorin). Then, a release agent particle dispersion (1) (solid content: 20% by mass) obtained by dispersing release agent particles having a volume average particle size of 230 nm was prepared. Moreover, it was 1.0 * 10 ^<-2 > (mol / g) when the coagulation value of the release agent particle | grains in a release agent particle dispersion liquid (1) was measured.

[Partition Agent Particle Dispersions (2) to (5)]
The release agent from the release agent particle dispersion (2) was the same as the release agent particle dispersion (1) except that the addition amount of the anionic surfactant and the dispersion treatment time were as shown in Table 2 below. A particle dispersion (5) was prepared. The volume average particle size of the release agent particles in the dispersion was 230 nm, and the solid content was 20% by mass. Table 2 shows the coagulation values of the release agent particles in the dispersion.

[Colorant particle dispersion (1)]
-Cyan pigment (manufactured by Dainichi Seika Co., Ltd., Pigment Blue 15: 3 (copper phthalocyanine)): 1000 parts-Anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd., Neogen R): 15 parts-Ion-exchanged water: 9000 Part The above are mixed, dissolved, and dispersed for about 1 hour using a high-pressure impact disperser Ultimateizer (manufactured by Sugino Machine Co., Ltd., HJP30006) to disperse a colorant (cyan pigment). Dispersion liquid (1) was prepared. The volume average particle diameter of the colorant (cyan pigment) in the colorant particle dispersion (1) was 0.16 μm, and the solid content concentration was 23%.

<Production of toner>
[Toner (1)]
Amorphous polyester resin dispersion (1): 450 parts Colorant particle dispersion (1): 21.74 parts Release agent particle dispersion (1): 50 parts Nonionic surfactant (IGEPAL CA897) ): 1.40 parts

-Mixed solution adjustment process-
The raw material was placed in a 2 L cylindrical stainless steel container and dispersed and mixed for 10 minutes while applying a shearing force at 4000 rpm with a homogenizer (manufactured by IKA, Ultra Lalux T50). Next, 1.75 parts of a 10% aqueous solution of nitric acid in polyaluminum chloride (polyaluminum chloride concentration: 10% by mass, nitric acid concentration: 0.3N) as a flocculant is gradually added dropwise, and the homogenizer is rotated at 5000 rpm for 15 minutes. And mixed to prepare a mixed solution.

-Aggregated particle adjustment process-
Thereafter, the mixed solution was transferred to a polymerization kettle equipped with a stirrer and a thermometer and started to be heated with a mantle heater to promote the growth of aggregated particles at 42 ° C. At this time, the pH of the raw material dispersion was controlled in the range of 2.2 to 3.5 with 0.3N nitric acid or 1N sodium hydroxide aqueous solution. The agglomerated particles were formed by maintaining the above pH range for about 2 hours. Under the present circumstances, the volume average particle diameter of the aggregated particle measured using Multisizer II (Aperture diameter: 50 micrometers, Beckman-Coulter company make) was 5.4 micrometers.

-Resin coated particle adjustment process-
Next, 100 parts of an amorphous polyester resin dispersion (1) was additionally added, and the resin particles of the amorphous polyester resin (1) were adhered to the surface of the aggregated particles to prepare resin-coated particles. The temperature was further raised to 44 ° C., and the resin-coated particles were prepared while confirming the size and shape of the particles with an optical microscope and Multisizer II.

-Fusion / unification process-
Thereafter, the pH was raised to 8.0 in order to fuse the aggregated particles, and then the temperature was raised to 95 ° C. After confirming that the resin-coated particles were fused with an optical microscope, the pH was lowered to 6.0 while maintaining the temperature at 95 ° C., and the heating was stopped after 1 hour, followed by cooling at a rate of temperature decrease of 1.0 ° C./min. Thereafter, the mixture was sieved with a 20 μm mesh, washed repeatedly with water, and then dried with a vacuum dryer to obtain toner particles (1). The obtained toner particles (1) had a volume average particle diameter of 6.2 μm and a GSDp-under of 1.20.

  The number of concave mold release agent exposed portions of toner particles (1) was determined from 100 toner particles from the SEM image, and the number of concave mold release agent exposed portions per toner particle was determined to be 2.0. Met.

  To 100 parts of toner particles (1), as an external additive, 1 part of silica particles (Nippon Aerosil Co., Ltd., hydrophobic silica: RX50) subjected to surface hydrophobization treatment and 100 parts of metatitanic acid are used. A reaction product obtained by treating 40 parts of isobutyltrimethoxysilane and 10 parts of trifluoropropyltrimethoxysilane was added to 1 part of metatitanic acid compound particles having an average primary particle diameter of 20 nm, and mixed for 5 minutes using a Henschel mixer. Further, the toner (1) was obtained by passing through an ultrasonic vibration sieve (Dalton).

[Toners (2) to (8)]
Instead of the amorphous polyester resin particle dispersion (1) and the release agent particle dispersion (1), toner particles (except for the resin particle dispersion and release agent particle dispersion shown in Table 3 below) were used. In the same manner as in 1) and toner (1), toner particles (2) to toner particles (8) and toner (2) to toner (8) were prepared. Table 3 shows the number of the concave mold release agent exposed portions of the toner particles.

[Toner (9)]
The toner particles (9) and the toner (9) were prepared in the same manner as the toner particles (1) and the toner (1) except that the agglomerated particles were used as they were without performing the resin-coated particle adjustment step. . On the surface of the toner particles, the release agent was exposed in a convex shape, but there was no concave release agent exposed portion.

<Creation of carrier>
Ferrite particles (volume average particle size: 35 μm, GSDv: 1.20): 100 parts Toluene: 14 parts Methyl methacrylate-perfluorooctylethyl acrylate copolymer (copolymerization ratio 8: 2, Mw = 78000, critical Surface tension: 24 dyn / cm): 1.6 parts carbon black (trade name: VXC-72, manufactured by Cabot, volume resistivity: 100 Ωcm or less): 0.12 parts Crosslinked melamine resin particles (average particle size: 0) 0.3 μm, toluene insoluble): 0.3 part

First, carbon black was diluted in toluene and added to a perfluoroacrylate copolymer and dispersed with a sand mill. Next, the above components other than the ferrite particles were dispersed therein with a stirrer for 10 minutes to prepare a coating layer forming solution. Next, this coating layer forming liquid and ferrite particles were put into a vacuum degassing type kneader and stirred at a temperature of 60 ° C. for 30 minutes, and then the pressure was reduced and toluene was distilled off to form a resin coating layer to obtain a carrier. .
The volume average particle size distribution index GSDv of the carrier was 1.20.

<Production of developer>
[Developer (1)]
The obtained toner (1): 36 parts and the carrier: 414 parts were put into a 2 liter V blender, stirred for 20 minutes, and then sieved at 212 μm to prepare developer (1).

[Developers (2) to (9)]
Developer (9) was produced from developer (2) in the same manner as developer (1) except that toner (2) to toner (9) were used instead of toner (1).

<Evaluation of toner>
[Powder fluidity]
The toner obtained by the above method was left in an environment of 55 ° C./50% RH for 24 hours.
Thereafter, 2 g of the toner is weighed, placed on a sieve having a mesh size of 32 μm, vibrated for 30 seconds, the amount remaining on the sieve is weighed, the degree of aggregation of the toner is calculated from the following formula, and the powder fluidity is evaluated. did.
Formula: degree of toner aggregation (%) = (amount of toner remaining on sieve (g) / 2 g) × 100
The evaluation criteria are as follows, and the results are shown in Table 4.

-Evaluation criteria-
○: Less than 5% △: 5% or more and less than 10% but no problem ×: 10% or more

[Thermal storage]
The toner obtained by the above method was left in an environment of 55 ° C./50% RH for 24 hours.
Then, using a powder tester (manufactured by Hosokawa Micron Co., Ltd.), 20 g of accurately weighed toner is put on a 53 μm sieve, vibrated for 90 seconds with an amplitude of 1 mm, and the toner mass on each sieve after vibration is measured. The thermal storage index was calculated as a percentage of the original sample mass (20 g). The measurement was performed in an environment of 25 ° C./50% RH. If the index of the heat storage property after vibration is less than 40%, it can usually be used without any practical problem, and more preferably less than 30%.
The evaluation criteria are as follows, and the results are shown in Table 4.

-Evaluation criteria-
○: Less than 30% △: 30% or more and less than 40% ×: 40% or more

[Photoconductor surface filming, decurler contamination, image defects]
The developer thus obtained was filled in a developing unit of a quadruple tandem type DocuCentre Color 500 (manufactured by Fuji Xerox Co., Ltd.) shown in FIG. 3, and left in an environment of 28 ° C./85% RH for 24 hours. After that, it was placed in the DocuCenter Color 500 and adjusted so that a halftone image having a toner loading of 0.1 mg / cm ² was developed on the photoconductor under the above environment, and image formation for 5000 sheets was performed.
The surface of the photoconductor, the decurler member, and the formed image were visually confirmed every 500 sheets, and filming of the photoconductor surface, contamination of the decurler member, and image defects were evaluated according to the following evaluation criteria. The results are shown in Table 4. The decurler member is a member on the downstream side of the fixing machine that prevents the sheet from warping due to fixing.

-Evaluation criteria for filming on photoreceptor surface-
○: Filming is not recognized up to 5000 sheets.
(Triangle | delta): Although filming is recognized slightly by 5000 sheets, it is satisfactory practically.
X: Filming is recognized before 5000 sheets, which is unacceptable.

-Evaluation criteria for decurler member contamination-
○: No contamination was observed up to 5000 sheets.
(Triangle | delta): Although contamination is recognized slightly by 5000 sheets, there is no problem practically.
X: Contamination was observed before 5000 sheets, which is unacceptable.

-Evaluation criteria for image defects-
A: Image defects are not recognized up to 5000 sheets.
A: Image defects are slightly recognized on 5000 sheets, but there is no practical problem.
X: Contamination was observed before 5000 sheets, which is unacceptable.

  From the results shown in Table 4, in the examples, the powder flowability and the heat storage property are better than those in the comparative examples, and the filming of the photoreceptor surface, contamination of the decurler member, and image defects are suppressed. I understand.

(A) Schematic diagram schematically showing the surface of the toner particles of the present embodiment, and (B) Schematic diagram showing an enlarged view of the periphery of the release agent exposed portion on the surface of the toner particles. It is 2-2 end face of Drawing 1 (B). 1 is a schematic configuration diagram illustrating an example of an image forming apparatus according to an exemplary embodiment. It is a schematic block diagram which shows an example of the process cartridge of this embodiment.

Explanation of symbols

1Y, 1M, 1C, 1K, 107 photoconductor (latent image holder)
2Y, 2M, 2C, 2K charging device 3Y, 3M, 3C, 3K laser beam (electrostatic latent image forming means)
3 Exposure devices 4Y, 4M, 4C, 4K, 111 Developing device (developing means)
5Y, 5M, 5C, 5K Primary transfer rollers 6Y, 6M, 6C, 6K, 113 Photoconductor cleaning device (cleaning means)
8Y, 8M, 8C, 8K Toner cartridge 10Y, 10M, 10C, 10K Unit 20 Intermediate transfer belt 22 Drive roller 24 Support roller 26 Secondary transfer roller (transfer means)
28, 115 Fixing device (fixing means)
30 Intermediate transfer member cleaning device 32 Decaler member 108 Charging roller 111A Developer holding member 112 Transfer device 116 Mounting rail 117 Opening portion 118 for static elimination exposure Opening portion 200 for exposure Process cartridge 210 Toner particle 212 Resin 214 Mold release Agent 216 Coating resin layer 218 Coating resin surface 220 Release agent exposed surface 222 Opening edge 224 Opening portion 226 Opening edge peripheral resin surface 228 Virtual plane 300, P Recording paper (transferred material)

Claims (8)

  An electrostatic latent image development comprising a binder resin and a release agent, having an exposed portion where the release agent is exposed on the surface of the toner, wherein the exposed surface of the exposed portion is present inside the surface of the toner Toner.   2. The electrostatic latent image developing toner according to claim 1, wherein the number of exposed portions is 0.01 or more and 5.0 or less per particle of the toner. 3. A resin particle dispersion adjusting step of adjusting a resin particle dispersion in which the first resin particles as the binder resin particles are dispersed;
A release agent particle dispersion adjusting step for adjusting a release agent particle dispersion in which release agent particles that are particles of the release agent are dispersed;
A mixed solution adjusting step of mixing the resin particle dispersion and the release agent particle dispersion to adjust a mixed solution containing the first resin particles and the release agent particles;
In the mixed solution, an aggregated particle adjusting step of adjusting aggregated particles formed by the aggregation of the first resin particles earlier than the release agent particles;
A resin-coated particle adjusting step of adjusting the resin-coated particles formed by coating the aggregated particles with the second resin particles that are particles of the binder resin;
The electrostatic latent image according to claim 1, further comprising a fusing / merging step of fusing and fusing the resin-coated particles to a temperature equal to or higher than a glass transition temperature of the second resin particles. A method for producing a developing toner. When the coagulation value of the first resin particles is Fp (mol / g) and the coagulation value of the release agent particles is Fw (mol / g), the following formulas (1), (2), and (3) The method for producing a toner for developing an electrostatic latent image according to claim 3, wherein:
Formula (1): 1 × 10 ⁻⁵ ≦ Fp ≦ 1 × 10 ⁻¹
Formula (2): 1 × 10 ⁻⁵ ≦ Fw ≦ 1 × 10 ⁻¹
Formula (3): Fp ≦ Fw   The electrostatic latent image developing toner according to claim 1 or 2, or the electrostatic latent image developing toner produced by the method of producing an electrostatic latent image developing toner according to claim 3 or 4. A developer for developing an electrostatic latent image. Toner that is removed from the image forming apparatus and supplied to at least developing means provided in the image forming apparatus is stored.
The toner is an electrostatic latent image developing toner according to claim 1 or 2, or an electrostatic latent image produced by the method of producing an electrostatic latent image developing toner according to claim 3 or 4. A toner cartridge which is a toner for image development.   A process cartridge comprising at least a developer holder and containing the developer for developing an electrostatic latent image according to claim 5. A latent image carrier,
An electrostatic latent image forming means for forming an electrostatic latent image on the surface of the latent image holding member;
Developing means for developing the electrostatic latent image as a toner image with a developer;
Transfer means for transferring the toner image formed on the latent image holding member onto a transfer target;
Fixing means for fixing the toner image transferred onto the transfer object,
The image forming apparatus according to claim 5, wherein the developer is a developer for developing an electrostatic latent image.

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