JP2009180931A - Toner for electrostatic charge image development, developer for electrostatic charge image development, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a toner for electrostatic charge image development, the toner having good low temperature fixability and reproducibility of thin lines. <P>SOLUTION: The toner has a core particle containing a crystalline resin and a shell layer containing an amorphous resin, wherein the content of the crystalline resin in the toner is from 15 wt% to 65 wt%, the melting point Tmc of the crystalline resin is from 25°C to 50°C, while the glass transition temperature Tg of the amorphous resin is from 60°C to 90°C, the acid value AVa of the amorphous resin is from 15 mgKOH/g to 50 mgKOH/g, and the acid value Avc of the crystalline resin satisfies the relationship of AVa>AVc. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electrostatic image developing toner, an electrostatic image developing developer, and an image forming apparatus.

  A method of visualizing image information through an electrostatic charge image such as electrophotography is currently used in various fields. In electrophotography, an electrostatic latent image is formed on an image carrier by a charging and exposure process (latent image forming process), and an electrostatic charge image developing toner (hereinafter sometimes simply referred to as “toner”). The electrostatic latent image is developed with a developer for developing an electrostatic charge image (hereinafter sometimes referred to simply as “developer”) (development process), and visualized through a transfer process and a fixing process. The developer used here includes a two-component developer composed of a toner and a carrier and a one-component developer using a magnetic toner or a non-magnetic toner alone. The toner is usually produced by a thermoplastic resin. A kneading and pulverizing method is used in which a binder resin such as a pigment is melt-kneaded with a colorant such as a pigment, a charge control agent, a release agent such as wax, and the like, cooled, pulverized, and further classified.

  As a means capable of intentionally controlling the toner shape and the toner surface structure in response to the demand for higher image quality of the image, a method for producing toner by a wet method has been proposed. Etc.

  On the other hand, in the electrophotographic method, from the viewpoint of energy saving, low temperature fixability of toner is strongly demanded for the purpose of reducing energy consumption in copying machines, laser printers and the like. In order to realize such low-temperature fixability, a toner having a capsule structure having a core particle containing a crystalline resin and a shell layer containing an amorphous resin covering the core particle is known. In addition, toners having low temperature fixability have been proposed (see, for example, Patent Documents 1 to 5).

Japanese Patent Laid-Open No. 2003-50478 JP 2004-37890 A JP 2004-46095 A JP 2005-77784 A JP 2006-65025 A

  The present invention relates to a toner for developing an electrostatic image having good low-temperature fixability and fine line reproducibility, a developer for developing an electrostatic image containing the toner, and an image forming apparatus using the developer.

  The present invention includes core particles containing a crystalline resin and a shell layer containing an amorphous resin, and the content of the crystalline resin in the toner is 15 wt% or more and 65 wt% or less, The melting point Tmc of the crystalline resin is 25 ° C. or higher and 50 ° C. or lower, the glass transition point Tg of the amorphous resin is 60 ° C. or higher and 90 ° C. or lower, and the acid value AVa of the amorphous resin is 15 mgKOH / g or higher and 50 mgKOH / G or less, and when the acid value of the crystalline resin is AVc, the toner for developing an electrostatic charge image has a relationship of AVa> AVc.

  In the electrostatic charge image developing toner, particles having a major axis diameter of 1.6α or more and 1.9α or less and a shape factor SF1 of 155 or more when the volume average particle diameter D50v of the toner is α. The toner content in the toner is preferably 4.0 pop% or less.

  In the electrostatic charge image developing toner, it is preferable that a difference AVa−AVc between the acid value AVa of the amorphous resin and the acid value AVc of the crystalline resin is 10 or more.

  In the electrostatic image developing toner, the toner preferably has a volume average particle diameter D50v of 1.5 μm or more and 5.0 μm or less.

  In the electrostatic image developing toner, the shell layer preferably has an average cross-sectional thickness of 0.2 μm or more and 1.5 μm or less.

  The present invention also provides an electrostatic charge image developing developer comprising the electrostatic charge image developing toner and a carrier.

  The present invention also provides an image carrier, latent image forming means for forming an electrostatic latent image on the surface of the image carrier, and developing the electrostatic latent image using a developer to form a toner image. The image forming apparatus includes a developing unit and a transfer unit that transfers the developed toner image to a transfer target, and the developer is the developer for developing an electrostatic image.

  According to claim 1 of the present invention, the content of the crystalline resin in the toner, the melting point Tmc of the crystalline resin, the glass transition point Tg of the amorphous resin, and the acid value AVA of the amorphous resin are out of this range. Yes, providing toner for developing electrostatic images with better low-temperature fixability and fine line reproducibility than the case where the relationship between the acid value AVa of the amorphous resin and the acid value AVc of the crystalline resin is not in this relationship can do.

  According to the second aspect of the present invention, the low-temperature fixability and the fine line reproducibility are compared with the case where the content of the particles having the major axis diameter and shape factor SF1 within the range of the toner is outside the range. Therefore, it is possible to provide a toner for developing an electrostatic charge image with better.

  According to claim 3 of the present invention, the low temperature fixability and fine line reproducibility are better than the case where the difference between the acid value AVa of the amorphous resin and the acid value AVc of the crystalline resin is outside this range. It is possible to provide a toner for developing an electrostatic image.

  According to the fourth aspect of the present invention, it is possible to provide a toner for developing an electrostatic charge image with better fine line reproducibility as compared with a case where the volume average particle diameter D50v of the toner is outside this range.

  According to claim 5 of the present invention, it is possible to provide a toner for developing an electrostatic charge image with better low-temperature fixability and fine line reproducibility than when the cross-sectional average thickness of the shell layer is outside this range. .

  According to the sixth aspect of the present invention, the content of the crystalline resin in the toner, the melting point Tmc of the crystalline resin, the glass transition point Tg of the amorphous resin, and the acid value AVA of the amorphous resin are out of this range. Yes, a developer for developing an electrostatic charge image having good low-temperature fixability and fine line reproducibility compared to the case where the relationship between the acid value AVa of the amorphous resin and the acid value AVc of the crystalline resin is not this relationship. Can be provided.

  According to claim 7 of the present invention, the content of the crystalline resin in the toner, the melting point Tmc of the crystalline resin, the glass transition point Tg of the amorphous resin, and the acid value AVA of the amorphous resin are out of this range. Yes, compared with the case where the relationship between the acid value AVa of the amorphous resin and the acid value AVc of the crystalline resin is not in this relationship, an image forming apparatus capable of fixing at a low temperature and having good fine line reproducibility is provided. can do.

  Embodiments of the present invention will be described below. This embodiment is an example for carrying out the present invention, and the present invention is not limited to this embodiment.

<Toner for electrostatic image development>
The electrostatic image developing toner according to the exemplary embodiment includes core particles including a crystalline resin and a shell layer including an amorphous resin, and the content of the crystalline resin in the toner is 15 wt% or more and 65%. The melting point Tmc of the crystalline resin is 25 ° C. or more and 50 ° C. or less, the glass transition point Tg of the amorphous resin is 60 ° C. or more and 90 ° C. or less, and the acid value AVA of the amorphous resin is It is 15 mgKOH / g or more and 50 mgKOH / g or less, and AVa> AVc when the acid value of the crystalline resin is AVc.

  As a method for producing toner for developing electrostatic images, various chemical toner production methods such as emulsion polymerization aggregation method, suspension polymerization method, dissolution suspension method, etc. have been developed and implemented in place of the conventional kneading and pulverization method. ing. For example, in the emulsion polymerization aggregation method, a resin dispersion formed by emulsion polymerization of a polymerizable monomer of a binder resin and a particle dispersion such as a colorant and a release agent are mixed in an aqueous system in the presence of a surfactant. While stirring and mixing in a solvent, the toner particles are aggregated and heated and fused (unified) to produce toner particles that are colored resin particles having a predetermined particle size, particle size, shape, and structure.

  When a toner having a core particle containing a crystalline resin and a shell layer containing an amorphous resin is produced by, for example, such an emulsion polymerization aggregation method, heat is applied together with pH adjustment in the aggregation process and the coalescence process. Thus, the agglomeration speed and the temporary shape are controlled. The particles are fused by heating at the same time. However, when the coalescence process is performed at a temperature equal to or higher than the melting point Tmc of the low melting crystalline resin, the viscosity is low in the liquid state. The highly hydrophobic crystalline resin is exposed on the toner surface and fused with other particles. Since the chargeability of the toner is proportional to the surface area of the toner particles, the fused particles greatly exceed the desired charge amount per particle, causing fogging or degrading fine line reproducibility. Also, when considering a reduction in the particle size of the toner, since the ratio of the surface area to the volume of the toner is reduced, the core layer is formed on the toner if the shell layer has a thickness similar to that of the toner having a relatively large particle size. The closing ratio becomes small, and the effects of the crystalline resin such as low-temperature fixability cannot be fully exhibited. If the melting point of the crystalline resin used for the core particles is low when the shell thickness is simply reduced, the crystalline resin is exposed to the toner surface at one time, and the generation of fused particles cannot be prevented.

  The reason why the crystalline resin is exposed on the toner surface is that, even in the aggregation process, even if the amorphous resin particles serving as the shell layer are added to the particle aggregates (core particles), the shape and surface of the original aggregates are not affected. It is conceivable that the core particles are not completely covered by the unevenness, resulting in a portion where the crystalline resin of the core particles is exposed on the toner surface.

  If the thickness of the shell layer is increased in order to prevent this, the functions of the colorant, release agent, crystalline resin, etc. contained in the core particles will be lost. Therefore, in this embodiment, by setting Tmc of the crystalline resin lower than the glass transition point Tg of the amorphous resin, that is, lower than the aggregation temperature, the core particles obtained by aggregation are in a liquid state containing a colorant or the like. It is what. Such a core particle component in a liquid state is almost spherical with almost no unevenness due to the action of surface tension or the like, and can be uniformly coated with a shell layer.

  In addition, by making the acid value AVa of the amorphous resin higher than the acid value AVc of the crystalline resin, the affinity with water, which is an agglomeration and temporary solvent, is high, that is, highly hydrophilic. Since the amorphous resin is higher, the highly hydrophobic crystalline resin can be prevented from being exposed on the toner surface.

  Further, it is desirable to have a shell layer in the small particle size toner. By making the acid value AVa of the amorphous resin larger than the acid value AVc of the crystalline resin, the affinity of the amorphous resin with water or the like is increased, so that a shell layer containing the amorphous resin is likely to be formed. However, in the case of a toner having a small particle size, since the distance from the surface that receives contraction pressure due to surface tension is short, the degree of freedom in which the constituents contained in the core particles can move is small, so an amorphous resin shell layer can be generated. First, it is desirable to have a shell layer covering the core particles.

  The content of the crystalline resin in the toner is in the range of 15% by weight to 65% by weight, and preferably in the range of 25% by weight to 55% by weight. In order to exhibit the advantage that the crystalline resin is crystalline at the time of fixing, it is desirable that the crystalline resin has a predetermined domain diameter, but in the case of a small particle size toner, the content of the crystalline resin in the toner If it is less than 15% by weight, the desired domain diameter cannot be formed. Further, when the content of the crystalline resin in the toner exceeds 65% by weight, the crystalline resin is exposed to the toner surface. Even if the content of the crystalline resin is relatively increased like the toner of the present embodiment by increasing the acid value AVc of the amorphous resin and making the crystalline resin at the time of aggregation into a liquid state, A shell layer can be formed.

  The melting point Tmc of the crystalline resin is 25 ° C. or higher and 50 ° C. or lower, and preferably 30 ° C. or higher and 45 ° C. or lower. When the melting point Tmc of the crystalline resin is less than 25 ° C., the crystalline resin becomes a liquid state near room temperature, and when it exceeds 50 ° C., the low-temperature fixability of the toner becomes insufficient.

  The glass transition point Tg of the amorphous resin is 60 ° C. or higher and 90 ° C. or lower, and preferably 60 ° C. or higher and 80 ° C. or lower. When the glass transition point Tg of the amorphous resin is less than 60 ° C., it becomes close to the melting point Tmc of the crystalline resin, and the crystalline resin is exposed on the toner surface. Since the fixing temperature is required, the advantage of using the low melting point binder resin is lost. If the glass transition point Tg of the amorphous resin is encapsulated at a relatively high temperature of 60 ° C. or more and 90 ° C. or less, it can be used as a toner even at a temperature equal to or higher than the melting point Tmc of the crystalline resin.

  The acid value AVa of the amorphous resin is 15 mgKOH / g or more and 50 mgKOH / g or less, and preferably 15 mgKOH / g or more and 40 mgKOH / g or less. When the acid value AVA of the amorphous resin is less than 15 mgKOH / g, a repulsive force with the internal hydrophobic material is generated. In the case of a toner having a small particle size, since the ratio of volume to surface area is small, the material transferred from the surface of the core particle can easily take a domain structure at the center. In the case of a release agent, a moderate sea-island structure is required for full function, so there is relatively no problem. However, when the pigment has a domain structure, the color developability and light transmittance deteriorate. End up. When the acid value AVA of the amorphous resin exceeds 50 mgKOH / g, depending on the pigment type contained in the core particles, the hydrophilicity exceeds that of the amorphous resin, and the surface exposure of the core particle components is induced.

  The difference AVa−AVc between the acid value AVa of the amorphous resin and the acid value AVc of the crystalline resin is 10 or more, and preferably 15 or more. If AVa-AVc is less than 10, the crystalline resin is exposed on the toner surface.

  When the volume average particle diameter D50v of the toner is α, the content in the toner of particles having a major axis diameter of 1.6α or more and 1.9α or less and a shape factor SF1 of 155 or more is 4.0 pop%. Or less, more preferably 3.0 pop% or less. When the content of such particles in the toner exceeds 4.0 pop%, the charge amount between the particles is different. Therefore, when a new developer is additionally supplied into the developing machine from the cartridge as the developer is consumed, In some cases, a desired charge amount is difficult to obtain in a short period of time, and a ground cover may occur on the blank paper portion of the document.

  The volume average particle diameter D50v of the toner is preferably 1.5 μm or more and 5.0 μm or less, and more preferably 2.2 μm or more and 4.5 μm or less. When the volume average particle diameter D50v of the toner is less than 1.5 μm, the shell layer of the amorphous resin may not be sufficiently provided by the particles, or particles of only the amorphous resin may be generated. If the thickness exceeds 0.0 μm, the fine line reproducibility may be difficult.

  The average cross-sectional thickness of the shell layer is preferably 0.2 μm or more and 1.5 μm or less, and more preferably 0.4 μm or more and 1.2 μm or less. When the average cross-sectional thickness of the shell layer is less than 0.2 μm, the crystalline resin may be exposed on the toner surface, and when it exceeds 5.0 μm, the ratio of the core particles closed to the toner becomes small, and the low-temperature fixability. In some cases, the effects of the crystalline resin cannot be sufficiently exhibited. In particular, when a toner having a small particle size is intended, it is desirable to make the thickness of the shell layer as thin as possible in order to fully exhibit the function of the core particles. The surface area and volume are proportional to the square and cube of the particle size, respectively. However, the smaller the particle size, the smaller the difference between the surface area and the volume. This is because it becomes smaller.

  The toner according to the exemplary embodiment can prevent fusion between particles even when coalescing and coalescing at a temperature equal to or higher than the melting point Tmc of the low-melting crystalline resin. It has a diameter and shape, and has low temperature fixability and fine line reproducibility.

  The toner according to the present embodiment is a toner having a low-temperature fixability, and includes a crystalline resin, a colorant, and the like, a core particle portion that mainly imparts low-temperature fixability, and a shell portion that covers the core particles. Is a so-called function-separated core-shell toner.

(Core particles)
The core particles of the toner according to the exemplary embodiment include a binder resin including a crystalline resin, and other components as necessary.

  First, the crystalline resin will be described. In the present embodiment, “crystallinity” of “crystalline resin” refers to having a clear endothermic peak rather than a stepwise endothermic amount change in differential scanning calorimetry (DSC) of the resin or toner. Specifically, in differential scanning calorimetry (DSC) using a differential scanning calorimeter (equipment name: DSC-60 type) manufactured by Shimadzu Corporation equipped with an automatic tangential processing system, a rate of temperature increase of 10 ° C./min. A “clear” endothermic peak is assumed when the temperature from the onset point to the top of the endothermic peak when the temperature is raised at 10 ° C. is within 10 ° C. Further, from the viewpoint of sharp melt, the temperature from the onset point to the peak top of the endothermic peak is preferably within 10 ° C, and more preferably within 6 ° C. Specify any point on the flat part of the baseline in the DSC curve and any point on the flat part of the falling part from the baseline, and the intersection of the tangents of the flat part between the two points is automatically set as the “onset point”. Obtained automatically by the tangent processing system. Further, the endothermic peak may show a peak having a width of 40 ° C. or more and 50 ° C. or less when the toner is used.

  Further, the “amorphous resin” used as the binder resin means that when the temperature from the onset point to the peak top of the endothermic peak exceeds 10 ° C. in the differential scanning calorimetry (DSC) of the resin or toner, or clearly It indicates that the resin does not show a significant endothermic peak. Specifically, in differential scanning calorimetry (DSC) using a differential scanning calorimeter (equipment name: DSC-60 type) manufactured by Shimadzu Corporation equipped with an automatic tangential processing system, a rate of temperature increase of 10 ° C./min. When the temperature from the onset point to the top of the endothermic peak when the temperature is raised at 10 ° C. exceeds 10 ° C., or when no clear endothermic peak is observed, it is assumed to be “amorphous”. Further, the temperature from the onset point to the peak top of the endothermic peak preferably exceeds 12 ° C., and more preferably no clear endothermic peak is observed. The method for obtaining the “onset point” in the DSC curve is the same as in the case of the “crystalline resin”.

  The crystalline resin is not particularly limited as long as it is a crystalline resin, and specific examples include crystalline polyester resins and crystalline vinyl resins. From the viewpoint of adjusting the melting point within a preferable range, a crystalline polyester resin is preferable. An aliphatic crystalline polyester resin having an appropriate melting point is more preferable.

  Crystalline vinyl resins include amyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, Undecyl (meth) acrylate, tridecyl (meth) acrylate, myristyl (meth) acrylate, cetyl (meth) acrylate, stearyl (meth) acrylate, oleyl (meth) acrylate, behenyl (meth) acrylate, etc. Examples thereof include vinyl resins using long-chain alkyl or alkenyl (meth) acrylic acid esters. In this specification, the description “(meth) acryl” means that both “acryl” and “methacryl” are included.

  On the other hand, the crystalline polyester resin is synthesized from an acid (dicarboxylic acid) component and an alcohol (diol) component. In this embodiment, the “acid-derived constituent component” refers to a component before synthesis of the polyester resin. The component part which was an acid component is pointed out, and the "alcohol-derived component" refers to the component part which was an alcohol component before the synthesis of the polyester resin.

  When the polyester resin is not crystalline, that is, amorphous, it tends to be unable to maintain toner blocking resistance and image storage stability while ensuring good low-temperature fixability. In the case of a polymer in which other components are copolymerized with respect to the crystalline polyester main chain, when the other components are 50% by weight or less, this copolymer is also called a crystalline polyester resin.

[Acid-derived components]
The acid-derived constituent component is preferably an aliphatic dicarboxylic acid, and particularly preferably a linear carboxylic acid. For example, succinic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelic acid, sebacic acid, 1,9-nonanedicarboxylic acid, 1,10-decanedicarboxylic acid, 1,11-undecanedicarboxylic acid Acid, 1,12-dodecanedicarboxylic acid, 1,13-tridecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, 1,16-hexadecanedicarboxylic acid, 1,18-octadecanedicarboxylic acid, etc., or lower alkyl esters thereof, Acid anhydrides can be mentioned but are not limited to these. Among the aliphatic dicarboxylic acids, in view of availability, sebacic acid and 1,10-decanedicarboxylic acid are preferable.

  As the acid-derived constituent component, in addition to the above-mentioned aliphatic dicarboxylic acid-derived constituent component, a constituent component such as a dicarboxylic acid-derived constituent component having a double bond, a dicarboxylic acid-derived constituent component having a sulfonic acid group, or the like is included. Is preferred. The component derived from a dicarboxylic acid having a double bond is derived from a lower alkyl ester or acid anhydride of a dicarboxylic acid having a double bond, in addition to a component derived from a dicarboxylic acid having a double bond. Components are also included. The dicarboxylic acid-derived component having a sulfonic acid group is derived from a lower alkyl ester or acid anhydride of a dicarboxylic acid having a sulfonic acid group, in addition to a component derived from a dicarboxylic acid having a sulfonic acid group. Components are also included.

  A dicarboxylic acid having a double bond can be suitably used to prevent hot offset at the time of fixing because the entire resin can be crosslinked using the double bond. Examples of such dicarboxylic acids include, but are not limited to, fumaric acid, maleic acid, 3-hexenedioic acid, and 3-octenedioic acid. Moreover, these lower alkyl esters, acid anhydrides, etc. are also mentioned. Among these, fumaric acid, maleic acid and the like are preferable in terms of cost.

  A dicarboxylic acid having a sulfonic acid group is effective in that it can favorably disperse a coloring material such as a pigment. Further, if a sulfonic acid group is present when the entire resin is emulsified or suspended in water to produce fine particles, it can be emulsified or suspended without using a surfactant, as will be described later. Examples of the dicarboxylic acid having a sulfonic acid group include, but are not limited to, 2-sulfoterephthalic acid sodium salt, 5-sulfoisophthalic acid sodium salt, and sulfosuccinic acid sodium salt. Moreover, these lower alkyl esters, acid anhydrides, etc. are also mentioned. Among these, 5-sulfoisophthalic acid sodium salt and the like are preferable in terms of cost.

  The content of acid-derived components other than these aliphatic dicarboxylic acid-derived components (dicarboxylic acid-derived component having a double bond and / or dicarboxylic acid-derived component having a sulfonic acid group) in the acid-derived component Is preferably 1 component mol% or more and 20 component mol% or less, more preferably 2 component mol% or more and 10 component mol% or less.

  When the content is less than 1 component mol%, pigment dispersion may not be good, the emulsified particle diameter may be large, and adjustment of the toner diameter by aggregation may be difficult. On the other hand, if it exceeds 20 component mol%, the crystallinity of the polyester resin is lowered, the melting point is lowered, the image storage stability is deteriorated, or the emulsion particle size is too small to dissolve in water, and no latex is produced. There is a case. In the present specification, “constituent mol%” refers to a percentage when each constituent component (acid-derived constituent component, alcohol-derived constituent component) in the polyester resin is 1 unit (mol).

[Alcohol-derived components]
The alcohol-derived constituent component is preferably an aliphatic diol, such as 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-tridecanediol, 1,14-tetradecanediol 1,18-octadecanediol, 1,20-eicosanediol, etc., but are not limited thereto. Among the aliphatic diols, 1,9-nonanediol and 1,10-decanediol are preferable in view of the melting point and resistance of the resin.

  The alcohol-derived constituent component preferably has an aliphatic diol-derived constituent component content of 80 constituent mol% or more, and includes other components as necessary. As the alcohol-derived constituent component, the content of the aliphatic diol-derived constituent component is more preferably 90 constituent mol% or more.

  When the content is less than 80 mol%, the crystallinity of the polyester resin is lowered and the melting point is lowered, so that toner blocking resistance, image storage stability and low-temperature fixability may be deteriorated. On the other hand, examples of other components included as necessary include components such as a diol-derived component having a double bond and a diol-derived component having a sulfonic acid group.

  Examples of the diol having a double bond include 2-butene-1,4-diol, 3-butene-1,6-diol, 4-butene-1,8-diol and the like. On the other hand, as the diol having a sulfonic acid group, 1,4-dihydroxy-2-sulfonic acid benzene sodium salt, 1,3-dihydroxymethyl-5-sulfonic acid benzene sodium salt, 2-sulfo-1,4-butane Examples include diol sodium salt.

  Alcohol-derived components in the case of adding alcohol-derived components other than these linear aliphatic diol-derived components (diol-derived component having a double bond and / or diol-derived component having a sulfonic acid group) As content in a component, 1 to 20 component mol% is preferable, and 2 to 10 component mol% is more preferable. When the content is less than 1 constituent mol%, pigment dispersion may be poor, the emulsified particle diameter may be large, and adjustment of the toner diameter by aggregation may be difficult. On the other hand, if it exceeds 20 component mol%, the crystallinity of the polyester resin is lowered, the melting point is lowered, the image storage stability is deteriorated, or the emulsion particle size is too small to dissolve in water, and no latex is produced. There is a case.

  The method for producing the polyester resin is not particularly limited and can be produced by a general polyester polymerization method in which an acid component and an alcohol component are reacted. Examples thereof include direct polycondensation and transesterification. Depending on the type of production. The molar ratio (acid component / alcohol component) when the acid component reacts with the alcohol component varies depending on the reaction conditions and the like, and cannot be generally stated, but is usually about 1/1.

  The polyester resin can be produced at a polymerization temperature of 180 ° C. or higher and 230 ° C. or lower. If necessary, the reaction system is reduced in pressure and reacted while removing water and alcohol generated during condensation. When the 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. In the case where a monomer having poor compatibility exists in the copolymerization reaction, it is preferable that the monomer having poor compatibility and the monomer and the acid or alcohol to be polycondensed are condensed in advance and then polycondensed together with the main component.

  Catalysts usable 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; metal compounds such as zinc, manganese, antimony, titanium, tin, zirconium and germanium. A phosphorous acid compound, a phosphoric acid compound, an amine compound, etc., specifically, the following compounds are mentioned.

  For example, sodium acetate, sodium carbonate, lithium acetate, calcium acetate, zinc stearate, zinc naphthenate, zinc chloride, manganese acetate, manganese naphthenate, titanium tetraethoxide, titanium tetrapropoxide, titanium tetraisopropoxide, titanium tetra Butoxide, 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-butylphenyl) phosphite Ethyltriphenylphosphonium bromide, triethylamine, compounds such as triphenyl amine.

  In addition to the polymerizable monomers described above for the purpose of adjusting the melting point, molecular weight, etc. of the crystalline resin that is the main component of the binder resin in the present embodiment, shorter chain alkyl groups, alkenyl groups, aromatic rings, etc. It is also possible to use compounds having Specific examples include dicarboxylic acids, alkyl dicarboxylic acids such as succinic acid, malonic acid, and oxalic acid, and phthalic acid, isophthalic acid, terephthalic acid, homophthalic acid, 4,4′-bibenzoic acid, 2,6- Examples include aromatic dicarboxylic acids such as naphthalenedicarboxylic acid and 1,4-naphthalenedicarboxylic acid, and nitrogen-containing aromatic dicarboxylic acids such as dipicolinic acid, dinicotinic acid, quinolinic acid, and 2,3-pyrazinedicarboxylic acid. Short chain alkyl diols such as succinic acid, malonic acid, acetone dicarboxylic acid, diglycolic acid, etc. In the case of short chain alkyl vinyl polymerizable monomers, methyl (meth) acrylate, (meth) Short chain alkyls such as ethyl acrylate, propyl (meth) acrylate, butyl (meth) acrylate, alkenyl (meth Acrylic esters, vinyl nitriles such as acrylonitrile and methacrylonitrile, vinyl ethers such as vinyl methyl ether and vinyl isobutyl ether, vinyl methyl ketone, vinyl ethyl ketone, vinyl isopropenyl ketones, ethylene, propylene, butadiene, isoprene, etc. Olefins and the like. These polymerizable monomers may be used individually by 1 type, and may use 2 or more types together.

  In the present embodiment, a compound having a hydrophilic polar group can be used as long as it is copolymerizable as a resin for an electrostatic charge image developing toner. As a specific example, when the resin used is a polyester, a dicarboxylic acid compound in which an aromatic ring such as sulfonyl-terephthalic acid sodium salt or 3-sulfonylisophthalic acid sodium salt is directly substituted with a sulfonyl group is used. In the case of a resin, unsaturated aliphatic carboxylic acids such as (meth) acrylic acid and itaconic acid, glycerin mono (meth) acrylate, fatty acid-modified glycidyl (meth) acrylate, zinc mono (meth) acrylate, zinc di (meth) acrylate, Esters of (meth) acrylic acid and alcohols such as 2-hydroxyethyl (meth) acrylate, polyethylene glycol (meth) acrylate, and polypropylene glycol (meth) acrylate, sulfonyl groups at any of the ortho, meta, and para positions Have Derivatives of styrene, sulfonyl group-substituted aromatic vinyl such as sulfonyl group-containing vinyl naphthalene.

  In addition, a cross-linking agent can be added to the crystalline resin in the present embodiment, if necessary, for the purpose of preventing gloss unevenness, color unevenness, hot offset, etc. during fixing in a high temperature region. Specific examples of the crosslinking agent include aromatic polyvinyl compounds such as divinylbenzene and divinylnaphthalene, divinyl phthalate, divinyl isophthalate, divinyl terephthalate, divinyl homophthalate, divinyl trimesate / trivinyl, divinyl naphthalenedicarboxylate, Polyvinyl esters of aromatic polyvalent carboxylic acids such as diphenyl biphenyl carboxylate, divinyl esters of nitrogen-containing aromatic compounds such as divinyl pyridine dicarboxylate, unsaturated heterocyclic compounds such as pyrrole and thiophene, vinyl pyromumate, Vinyl esters of unsaturated heterocyclic compounds such as vinyl furancarboxylate, vinyl pyrrole-2-carboxylate, vinyl thiophenecarboxylate, butanediol methacrylate, hexanediol acrylate, octanediol methacrylate (Meth) acrylic acid esters of linear polyhydric alcohols such as relate, decanediol acrylate and dodecanediol methacrylate, branching such as neopentylglycol dimethacrylate, 2-hydroxy, 1,3-diacryloxypropane, (Meth) acrylic acid esters of polyhydric alcohols, polyethylene glycol di (meth) acrylate, polypropylene polyethylene glycol di (meth) acrylates, divinyl succinate, divinyl fumarate, vinyl / divinyl maleate, divinyl diglycolate, itaconic acid Vinyl / divinyl, divinyl acetone dicarboxylate, divinyl glutarate, divinyl 3,3′-thiodipropionate, divinyl aconite / trivinyl, divinyl adipate, divinyl pimelate Divinyl suberic, azelaic, divinyl sebacate, divinyl dodecanedioate divinyl, the polyvinyl esters of polycarboxylic acids such as oxalic acid divinyl and the like.

  In particular, when the crystalline resin is polyester, unsaturated polycarboxylic acids such as fumaric acid, maleic acid, itaconic acid, and trans-aconitic acid are copolymerized in the polyester, and then multiple bond portions in the resin are bonded together. Alternatively, a method of crosslinking using another vinyl compound may be used. In this embodiment, these crosslinking agents may be used individually by 1 type, and may be used in combination of 2 or more types.

  As a method of cross-linking with these cross-linking agents, a method of polymerizing and cross-linking with a cross-linking agent at the time of polymerization of the polymerizable monomer may be used, or after the unsaturated portion remains in the resin and the resin is polymerized, or a toner is produced. Thereafter, a method of crosslinking the unsaturated portion by a crosslinking reaction may be used.

  When the resin to be used is polyester, the polymerizable monomer can be polymerized by condensation polymerization. As the polycondensation catalyst, known ones can be used. Specific examples include titanium tetrabutoxide, dibutyltin oxide, germanium dioxide, antimony trioxide, tin acetate, zinc acetate, tin disulfide and the like. Can be mentioned. When the resin to be used is a vinyl resin, the polymerizable monomer can be polymerized by radical polymerization.

  The radical polymerization initiator is not particularly limited as long as it is capable of emulsion polymerization. Specifically, hydrogen peroxide, acetyl peroxide, cumyl peroxide, tert-butyl peroxide, propionyl peroxide, benzoyl peroxide, chlorobenzoyl peroxide, dichlorobenzoyl peroxide, bromomethylbenzoyl peroxide, lauroyl peroxide , Ammonium persulfate, sodium persulfate, potassium persulfate, diisopropyltetralin hydroperoxide, 1-phenyl-2-methylpropyl-1-hydroperoxide, pertriphenylacetic acid-tert-butyl hydroperoxide, tert-butyl formate, Peroxides such as tert-butyl peracetate, tert-butyl perbenzoate, tert-butyl perphenylacetate, tert-butyl permethoxyacetate, tert-butyl perN- (3-toluyl) carbamate, 2,2 '-Azobisp Bread, 2,2′-dichloro-2,2′-azobispropane, 1,1′-azo (methylethyl) diacetate, 2,2′-azobis (2-amidinopropane) hydrochloride, 2,2 ′ -Azobis (2-amidinopropane) nitrate, 2,2'-azobisisobutane, 2,2'-azobisisobutyramide, 2,2'-azobisisobutyronitrile, 2,2'-azobis-2- Methyl methylpropionate, 2,2′-dichloro-2,2′-azobisbutane, 2,2′-azobis-2-methylbutyronitrile, dimethyl 2,2′-azobisisobutyrate, 1,1′-azobis (1 -Sodium methylbutyronitrile-3-sulfonate), 2- (4-methylphenylazo) -2-methylmalonodinitrile, 4,4'-azobis-4-cyanovaleric acid, 3,5-dihy Roxymethylphenylazo-2-methylmalonodinitrile, 2- (4-bromophenylazo) -2-allylmalonodinitrile, 2,2′-azobis-2-methylvaleronitrile, 4,4′-azobis-4 -Dimethyl cyanovalerate, 2,2'-azobis-2, 4-dimethylvaleronitrile, 1,1'-azobiscyclohexanenitrile, 2,2'-azobis-2-propylbutyronitrile, 1,1'- Azobis-1-chlorophenylethane, 1,1′-azobis-1-cyclohexanecarbonitrile, 1,1′-azobis-1-cycloheptanenitrile, 1,1′-azobis-1-phenylethane, 1,1 ′ -Azobiscumene, 4-nitrophenylazobenzyl cyanoacetate ethyl, phenylazodiphenylmethane, phenylazotriphenylmeth Tan, 4-nitrophenylazotriphenylmethane, 1,1′-azobis-1,2-diphenylethane, poly (bisphenol A-4,4′-azobis-4-cyanopentanoate), poly (tetraethylene glycol) -2,2'-azobisisobutyrate) and the like, 1,4-bis (pentaethylene) -2-tetrazene, 1,4-dimethoxycarbonyl-1,4-diphenyl-2-tetrazene and the like Can be mentioned.

  The polymerization initiator can also be used as an initiator for a crosslinking reaction in the crosslinking step.

  The weight average molecular weight (Mw) of the crystalline resin is preferably in the range of 10,000 to 30,000, more preferably in the range of 20,000 to 30,000. If the Mw is less than 10,000, the image durability may be lowered and the inclusion property may be lowered due to an increase in the acid value. If the Mw is more than 30000, the compatibility of the amorphous resin may be lowered. The number average molecular weight (Mn) of the crystalline resin is preferably 2000 or more, and more preferably 4000 or more. When the number average molecular weight (Mn) is less than 2000, the toner permeates into the surface of a recording medium such as paper at the time of fixing to cause uneven fixing, and the strength against bending resistance of the fixed image decreases, which is not preferable.

(Shell layer)
In the toner according to the exemplary embodiment, the shell layer covering the core particles mainly contains an amorphous resin for the purpose of imparting filming resistance.

  The amorphous resin used in the toner according to the exemplary embodiment is not particularly limited. Specifically, styrenes such as styrene, parachlorostyrene, and α-methylstyrene; methyl acrylate, ethyl acrylate, acrylic acid acrylic monomers such as n-propyl, butyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate; methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate, etc. Methacrylic monomers; Ethylene unsaturated acid monomers such as acrylic acid, methacrylic acid and sodium styrenesulfonate; Vinyl nitriles such as acrylonitrile and methacrylonitrile; Vinyl ethers such as vinyl methyl ether and vinyl isobutyl ether Kind Vinyl ketones such as vinyl methyl ketone, vinyl ethyl ketone and vinyl isopropenyl ketone; homopolymers of olefin monomers such as ethylene, propylene and butadiene, copolymers obtained by combining two or more of these monomers, or Mixtures thereof, furthermore, epoxy resins, polyester resins, polyurethane resins, polyamide resins, cellulose resins, polyether resins, etc., non-vinyl condensation resins, or mixtures thereof with the vinyl resins, in the presence of these Examples thereof include a graft polymer obtained by polymerizing a vinyl monomer. These resins may be used alone or in combination of two or more. Of these resins, styrene resins and acrylic resins are particularly preferable.

  The weight average molecular weight (Mw) of the amorphous resin is preferably in the range of 10,000 to 50,000, more preferably in the range of 15,000 to 45,000. If Mw is less than 10,000, offset may occur at the time of high-temperature fixing or image strength may deteriorate, and if it exceeds 50,000, low-temperature fixability may be deteriorated or gloss of a fixed image may decrease. . The number average molecular weight (Mn) of the amorphous resin is preferably in the range of 5000 to 40000, and more preferably in the range of 8000 to 35000. If Mn is less than 5000, the strength of the fixed image may be reduced. If it exceeds 40000, the low-temperature fixability may be deteriorated, or the gloss of the fixed image may be reduced.

  The colorant used in the toner of the exemplary embodiment may be a dye or a pigment, but a pigment is preferable from the viewpoint of light resistance and water resistance. Preferred pigments include 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, benzidine 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 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. A known pigment such as CI Pigment Blue 15: 3 can be used. Magnetic powder can also be used as a colorant. As the magnetic powder, known magnetic materials such as ferromagnetic metals such as cobalt, iron and nickel, alloys of metals such as cobalt, iron, nickel, aluminum, lead, magnesium, zinc and manganese, and oxides can be used.

  These can be used alone or in combination of two or more. The content of these colorants is preferably from 0.1 to 40 parts by weight, more preferably from 1 to 30 parts by weight, based on 100 parts by weight of the binder resin.

  In addition, each color toner such as yellow toner, magenta toner, cyan toner, and black toner can be obtained by appropriately selecting the type of the colorant.

  There is no restriction | limiting in particular as another component, According to the objective, it can select suitably, For example, well-known various additives, such as an inorganic particle, a charge control agent, a mold release agent, etc. are mentioned.

  If necessary, inorganic particles may be added to the toner of this embodiment. As the inorganic particles, silica particles, titanium oxide particles, alumina particles, cerium oxide particles, or known inorganic particles such as those obtained by hydrophobizing the surface thereof can be used alone or in combination of two or more kinds. Silica particles having a refractive index smaller than that of the binder resin are preferable from the viewpoint that transparency such as color developability and OHP permeability is not impaired. 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, silicone oil or the like are preferable.

  By adding these inorganic particles, the viscoelasticity of the toner can be adjusted, and the glossiness of the image and the penetration into the paper can be adjusted. The inorganic particles are preferably contained in an amount of 0.5% to 20% by weight, more preferably 1% to 15% by weight, based on 100 parts by weight of the toner raw material.

  A charge control agent may be added to the toner of the exemplary embodiment as necessary. As the charge control agent, chromium-based azo dyes, iron-based azo dyes, aluminum azo dyes, salicylic acid metal complexes, and the like can be used.

  The toner of this embodiment preferably contains a release agent. By including a release agent, the releasability in the fixing process is improved. In the contact heating type fixing method, the release oil applied to the fixing roll can be reduced or eliminated. Deterioration of roll life and oil streaks can be avoided, and the cost can be reduced.

  Specific examples of the release agent include low molecular weight polyolefins such as polyethylene, polypropylene and polybutene; silicones having a softening point by heating; fatty acid amides such as oleic acid amide, erucic acid amide, ricinoleic acid amide and stearic acid amide Plant waxes such as carnauba wax, rice wax, candelilla wax, tree wax, jojoba oil; animal waxes such as beeswax; minerals such as montan wax, ozokerite, ceresin, paraffin wax, microcrystalline wax, and Fischer-Tropsch wax・ Petroleum-based wax.

  The melting point of the release agent is preferably 50 ° C. or higher and 120 ° C. or lower, and more preferably below the melting point of the binder resin. If the melting point of the release agent is less than 50 ° C., the change temperature of the release agent is too low, and the blocking resistance may be inferior, or the developability may deteriorate when the temperature in the copying machine increases. On the other hand, when it exceeds 120 ° C., the change temperature of the release agent is too high, and the low-temperature fixability of the crystalline resin may be impaired.

  Moreover, these mold release agents may be used individually by 1 type, and may be used in combination of 2 or more type.

  The content of the release agent is preferably 1 part by weight or more and 20 parts by weight or less, more preferably 2 parts by weight or more and 15 parts by weight or less with respect to 100 parts by weight of the toner raw material. If the amount is less than 1 part by weight, the effect of adding the release agent may not be obtained. If the amount exceeds 20 parts by weight, the adverse effect on the chargeability tends to appear, and the toner is easily destroyed inside the developing machine, so that the release is performed. In addition to the effect that the agent or toner resin becomes spent on the carrier and the charge is likely to decrease, for example, when color toner is used, the surface of the image at the time of fixing becomes insufficient. The release agent is likely to stay in the image, and transparency may be deteriorated.

<Method for producing toner for developing electrostatic image>
The toner manufacturing method according to this embodiment is preferably a wet granulation method in which at least a resin particle dispersion and a colorant particle dispersion are mixed, and a flocculant is added to grow particles. As specific examples of this wet granulation method, the following emulsion aggregation method is preferably exemplified. Hereinafter, the emulsion aggregation method will be described as an example.

  The emulsion aggregation method includes an emulsification step of emulsifying a binder resin to form emulsion particles (droplets), an aggregation step of forming an aggregate of the emulsion particles (droplets), and the melting point of the binder resin. And a coalescing step for fusing at the above temperatures and heat coalescence. Alternatively, instead of the aggregation step and the coalescence step, a so-called association step may be performed in which aggregation and coalescence are performed simultaneously by aggregating at a temperature equal to or higher than the melting point of the binder resin.

  In the emulsification step, the emulsified particles (droplets) of the crystalline resin are mixed into a solution obtained by mixing an aqueous medium, a sulfonated crystalline resin and a mixed liquid (polymer liquid) containing a colorant as necessary. It is formed by applying a shearing force.

  At that time, by heating to a temperature equal to or higher than the melting point Tmc of the crystalline resin, the viscosity of the polymer liquid can be lowered to form emulsified particles. Moreover, a dispersing agent can also be used for stabilization of emulsified particles and thickening of the aqueous medium. Hereinafter, such a dispersion of emulsified particles may be referred to as a “resin particle dispersion”.

  Examples of the dispersant include water-soluble polymers such as polyvinyl alcohol, methyl cellulose, carboxymethyl cellulose, and sodium polyacrylate; sodium dodecylbenzenesulfonate, sodium octadecyl sulfate, sodium oleate, sodium laurate, potassium stearate, and the like. Anionic surfactants; cationic surfactants such as laurylamine acetate and lauryltrimethylammonium chloride; zwitterionic surfactants such as lauryldimethylamine oxide; polyoxyethylene alkyl ether, polyoxyethylene alkylphenyl ether, poly Surfactants such as nonionic surfactants such as oxyethylene alkylamine; tricalcium phosphate, aluminum hydroxide, calcium sulfate, calcium carbonate Include inorganic compounds such as barium carbonate.

  The amount of the dispersant used is preferably 0.01 parts by weight or more and 20 parts by weight or less with respect to 100 parts by weight of the binder resin of the core particles.

  In the emulsification step, the crystalline resin is copolymerized with a dicarboxylic acid having a sulfonic acid group (that is, the acid-derived constituent component contains a suitable amount of a dicarboxylic acid-derived constituent component having a sulfonic acid group). In addition, it is preferable because the dispersion stabilizer such as a surfactant can be reduced, or emulsion particles can be formed without using it.

  Examples of the emulsifier used when forming the emulsified particles include a homogenizer, a homomixer, a pressure kneader, an extruder, and a media disperser. The size of the emulsified particles (droplets) of the crystalline resin is preferably 0.005 μm or more and 1 μm or less, and more preferably 0.01 μm or more and 0.4 μm or less in terms of the average particle diameter (volume average particle diameter). If it is less than 0.005 μm, it will be almost dissolved in water, making it difficult to produce particles, and if it exceeds 1 μm, it will be difficult to obtain toner particles having a desired particle size of 1.5 μm to 5.0 μm. There is a case.

  As a method for dispersing the colorant, an arbitrary method, for example, a general dispersion method such as a rotary shear type homogenizer, a ball mill having a medium, a sand mill, or a dyno mill can be used.

  If necessary, an aqueous dispersion of these colorants can be prepared using a surfactant. Hereinafter, such a colorant dispersion may be referred to as a “colored particle dispersion”. As the surfactant and the dispersing agent used for dispersion, the same dispersing agents that can be used when dispersing the crystalline polyester resin can be used.

  In addition, a colorant can be mixed into the resin before forming the emulsified particles. Examples of the method of mixing the colorant into the resin include melt dispersion using a disperser or the like.

  In the aggregation step, the obtained emulsified particles are aggregated by heating to a temperature near the melting point Tmc of the crystalline resin or a temperature not higher than the glass transition point Tg of the amorphous resin to form an aggregate.

  Formation of the aggregate of the emulsified particles can be performed by making the pH of the emulsion liquid acidic with stirring. The pH is preferably 2 or more and 6 or less, and more preferably 2.5 or more and 5 or less. At this time, it is also effective to use a flocculant.

  As the aggregating agent used in the aggregating step, a surfactant having a polarity opposite to that of the surfactant used for the dispersing agent, an inorganic metal salt, or a divalent or higher-valent metal complex can be preferably used. In particular, the use of a metal complex is particularly preferable because the amount of the surfactant used can be 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.

  Further, when the aggregated particles have reached a desired particle size, by adding amorphous resin particles, a toner having a structure in which the surface of the core aggregated particles is coated with the amorphous resin can be produced. Since the crystalline resin is less likely to be exposed on the toner surface, this is a desirable configuration from the viewpoint of chargeability and developability. In the case of additional addition, a flocculant may be added or pH adjustment may be performed before additional addition.

  In the fusion / unification step, the agglomeration is stopped by increasing the pH of the suspension of the aggregated particles to a range of 3 to 9 under the stirring conditions according to the aggregation step. The aggregated particles are fused by heating at a temperature equal to or higher than the melting point Tmc. Further, when coated with the amorphous resin, the amorphous resin is also fused to coat the core particles. The heating time may be as long as fusion is performed, and may be performed for about 0.5 hours to 3 hours. If a longer time is taken, the release agent contained in the aggregated particles is likely to be exposed on the toner surface. Therefore, although it is effective for fixing properties, it is not preferable to heat for a long time because it adversely affects the storage stability of the toner.

  Thereafter, when the temperature is lowered to a temperature lower than the crystallization temperature of the crystalline resin to solidify the particles, the particle shape and surface properties change depending on the temperature lowering rate. For example, when the temperature is lowered at a high speed, the spheroidization and the surface are easily smoothed. On the other hand, when the temperature is slowly lowered, the particle shape becomes indefinite and irregularities are easily generated on the particle surface. Therefore, it is preferable to lower the temperature to a temperature equal to or lower than the crystallization temperature of the crystalline resin at a rate of at least 1 ° C./min, preferably at a rate of 3 ° C./min. The toner base particles having a desired BET specific surface area of 2 to 5 and a shape factor SF1 of 110 to 140 are obtained by lowering the temperature at a rate of 1 ° C./min or more and crystallizing the binder resin. be able to.

  The particles obtained by fusing can be made into toner mother particles through a solid-liquid separation process such as filtration and, if necessary, a washing process and a drying process. In this case, in order to ensure sufficient charging characteristics and reliability as a toner, it is preferable to sufficiently wash in the washing step.

  In the drying process, an arbitrary method such as a normal vibration type fluidized drying method, a spray drying method, a freeze drying method, or a flash jet method can be adopted. The toner base particles are preferably adjusted to have a moisture content after drying of 1.5% by weight or less, preferably 1.0% by weight or less.

  In the coalescence step or the association step, a crosslinking reaction may be performed when the crystalline resin is heated to the melting point Tmc or higher, or after the coalescence is completed. When the crosslinking reaction is performed, for example, an unsaturated sulfonated crystalline polyester resin obtained by copolymerizing a double bond component is used as the binder resin, and for example, t-butylperoxy-2-ethylhexa is added to this resin. A crosslinking reaction is introduced by causing a radical reaction using a polymerization initiator such as noate.

  The polymerization initiator may be mixed with the polymer in advance before the emulsification step, or may be incorporated into the aggregate in the aggregation step. Further, it may be introduced after the coalescence or association process, or after the coalescence or association process. In this case, a solution obtained by dissolving a polymerization initiator in an organic solvent may be added to a particle dispersion (resin particle dispersion or the like). These polymerization initiators may be added with known crosslinking agents, chain transfer agents, polymerization inhibitors and the like for the purpose of controlling the degree of polymerization.

  According to the toner manufacturing method described above, the toner particle shape and surface smoothness can be controlled. The particle shape of the toner is preferably close to a sphere. By making it spherical, the non-electrostatic adhesive force is reduced, so that the transferability is improved, and further, the charge amount on the toner surface becomes uniform, and the charge maintenance property is also improved.

  In the toner of this embodiment, an external additive such as a fluidizing agent or an auxiliary agent may be added to the surface of the toner particles. As external additives, known particles such as silica particles, titanium oxide particles, alumina particles, cerium oxide particles, inorganic particles such as carbon black, polymer particles such as polycarbonate, polymethyl methacrylate, and silicone resin whose surfaces have been hydrophobized. Can be used. The particle size of the external additive is preferably 30 nm to 200 nm, and more preferably 30 nm to 180 nm. By reducing the particle size of the toner, non-electrostatic adhesion to the photosensitive member is increased, causing transfer failure and causing transfer unevenness such as a superimposed image. It is preferable to add a large-sized external additive having a secondary particle size of 30 nm to 200 nm to improve transferability. If the volume average primary particle size is smaller than 30 nm, the initial toner fluidity is good, but the non-electrostatic adhesion between the toner and the photoreceptor cannot be sufficiently reduced, resulting in a decrease in transfer efficiency and image quality. Doing so, deterioration of image uniformity, and stress in the developing machine over time causes the particles to be embedded in the toner surface, changing the chargeability and causing problems such as lower copy density and fogging on the background. There is a case. On the other hand, if the volume average primary particle diameter is larger than 200 nm, it may be easily detached from the toner surface and the fluidity may be deteriorated.

<Physical properties of toner for developing electrostatic image>
As described above, the volume average particle size of the electrostatic image developing toner according to the exemplary embodiment is preferably in the range of 1.5 μm to 5.0 μm, more preferably in the range of 2.2 μm to 4.5 μm. The number average particle diameter is preferably in the range of 3 μm to 7 μm, and more preferably in the range of 4 μm to 6 μm.

  The volume average particle size and the number average particle size can be measured by measuring with a 100 μm aperture diameter using a Coulter Multisizer II type (manufactured by Beckman-Coulter). At this time, 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.

  The volume average particle size distribution index GSDv of the toner for developing an electrostatic charge image according to this embodiment is preferably 1.27 or less, more preferably 1.25 or less. When GSDv exceeds 1.27, the particle size distribution is not sharp, resolution is deteriorated, and image defects such as toner scattering and fogging may be caused.

The volume average particle diameter D50v and the volume average particle size distribution index GSDv can be obtained as follows. Draw cumulative distributions from the small diameter side for the particle size range (channel) divided based on the particle size distribution of the toner measured by the above-mentioned Coulter Multisizer II type (manufactured by Beckman-Coulter). In addition, the particle diameter that is accumulated 16% is defined as volume D16v and several D16p, the particle diameter that is accumulated 50% is defined as volume D50v and several D50p, and the particle diameter that is accumulated 84% is defined as volume D84v and several D84p. At this time, D50v represents the volume average particle diameter, and the volume average particle size distribution index (GSDv) is obtained as (D84v / D16v) ^1/2 . In addition, (D84p / D16p) ^1/2 represents a number average particle size distribution index (GSDp).

In addition, the shape factor SF1 represented by the following formula of the toner for developing an electrostatic charge image according to the exemplary embodiment is preferably in the range of 110 to 140, more preferably in the range of 115 to 130.
SF1 = (ML ² / A) × (π / 4) × 100
[Where, ML represents the maximum length (μm) of toner, and A represents the projected area (μm ² ) of toner. ]
If the toner shape factor SF1 is less than 110 or exceeds 140, it may be impossible to obtain excellent chargeability, cleanability, and transferability over a long period of time.

In addition, shape factor SF1 was measured as follows using a Luzex image analyzer (manufactured by Nireco Corporation, FT). First, an optical microscopic image of toner spread on a slide glass is taken into a Luzex image analyzer through a video camera, and the maximum length (ML) and projected area (A) of 1000 to 1200 toners are measured. For the toner, (ML ² / A) × (π / 4) × 100 was calculated, and an average of these values was obtained as the shape factor SF1.

<Developer for developing electrostatic image>
In the present embodiment, the developer for developing an electrostatic image is not particularly limited except that it contains the toner for developing an electrostatic image of the present embodiment, and can have an appropriate component composition depending on the purpose. The electrostatic charge image developing developer in the present embodiment is a one-component electrostatic charge image developing developer when the electrostatic charge image developing toner is used alone, or a two-component developer when used in combination with a carrier. It becomes a developer for developing an electrostatic image.

  For example, in the case of using a carrier, the carrier is not particularly limited, and examples thereof include known carriers. For example, resins described in JP-A Nos. 62-39879 and 56-11461 are disclosed. Known carriers such as a coated carrier can be used.

  Specific examples of the carrier include the following resin-coated carriers. Examples of the core particles of the carrier include normal iron powder, ferrite, and magnetite molding, and the volume average particle size is in the range of about 30 μm to 200 μm.

  Examples of the coating resin for the resin-coated carrier include styrenes such as styrene, parachlorostyrene, and α-methylstyrene; methyl acrylate, ethyl acrylate, n-propyl acrylate, lauryl acrylate, acrylic acid 2 -Α-methylene fatty acid monocarboxylic acids such as ethylhexyl, methyl methacrylate, n-propyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate; nitrogen-containing acrylics such as dimethylaminoethyl methacrylate; acrylonitrile, methacrylonitrile, etc. Vinyl nitriles; vinyl pyridines such as 2-vinyl pyridine and 4-vinyl pyridine; vinyl ethers such as vinyl methyl ether and vinyl isobutyl ether; vinyl methyl ketone, vinyl ethyl ketone, vinyl isopropenyl Homopolymers such as vinyl ketones such as ketones; olefins such as ethylene and propylene; vinyl-based fluorine-containing monomers such as vinylidene fluoride, tetrafluoroethylene and hexafluoroethylene; and copolymers composed of two or more types of monomers Furthermore, silicone resins containing methyl silicone, methyl phenyl silicone, etc., polyesters containing bisphenol, glycol, etc., epoxy resins, polyurethane resins, polyamide resins, cellulose resins, polyether resins, polycarbonate resins and the like can be mentioned. Of these, it is necessary to obtain a favorable chargeability for the binder resin without affecting the chargeability for the hindered phenol aliphatic carboxylic acid derivative. From these viewpoints, polystyrene, poly (meth) acrylate Or a copolymer thereof can be preferably used. These resins may be used alone or in combination of two or more. The coating amount of the coating resin is preferably in the range of about 0.1 to 10 parts by weight and more preferably in the range of 0.5 to 3.0 parts by weight with respect to 100 parts by weight of the core particles. preferable.

  For the manufacture of the carrier, a heating kneader, a heating Henschel mixer, a UM mixer, or the like can be used. Depending on the amount of the coating resin, a heating fluidized rolling bed, a heating kiln, or the like can be used. .

  The mixing ratio of the electrostatic image developing toner of the present embodiment and the carrier in the developer for developing an electrostatic image is not particularly limited and may be appropriately selected depending on the purpose.

<Image forming apparatus>
The image forming apparatus according to the present embodiment includes an image carrier, latent image forming means for forming an electrostatic latent image on the surface of the image carrier, and developing the electrostatic latent image with a developer to form a toner image. A developing unit that forms the toner image, and a transfer unit that transfers the developed toner image to the transfer target. The developer for developing an electrostatic charge image is used as the developer. In addition, the image forming apparatus according to the present embodiment includes means other than those described above, for example, charging means for charging the image holding member, fixing means for fixing the toner image transferred to the surface of the transfer target, and the surface of the image holding member. It may also include a cleaning means for removing the remaining toner.

  An example of the image forming apparatus according to the present embodiment is schematically shown in FIG. The image forming apparatus 1 includes a charging unit 10, an exposure unit 12, an electrophotographic photosensitive member 14 that is an image holding member, a developing unit 16, a transfer unit 18, a cleaning unit 20, and a fixing unit 22.

  In the image forming apparatus 1, the charging unit 10 that is a charging unit that charges the surface of the electrophotographic photosensitive member 14 and the charged electrophotographic photosensitive member 14 are exposed around the electrophotographic photosensitive member 14 according to image information. The exposure unit 12 is a latent image forming unit that forms an electrostatic latent image, the developing unit 16 is a developing unit that develops the electrostatic latent image with toner to form a toner image, and the surface of the electrophotographic photoreceptor 14. A transfer unit 18 that is a transfer unit that transfers the toner image formed on the surface of the transfer target 24, and a cleaning unit 20 that is a cleaning unit that removes toner remaining on the surface of the electrophotographic photosensitive member 14 after transfer. Are arranged in this order. A fixing unit 22 that is a fixing unit that fixes the toner image transferred to the transfer target 24 is arranged on the left side of the transfer unit 18.

  An operation of the image forming apparatus 1 according to the present embodiment will be described. First, the surface of the electrophotographic photosensitive member 14 is uniformly charged by the charging unit 10 (charging process). Next, light is applied to the surface of the electrophotographic photosensitive member 14 by the exposure unit 12, and the charged charges in the irradiated portion are removed, and an electrostatic charge image (electrostatic latent image) is formed according to the image information. (Latent image forming step). Thereafter, the electrostatic charge image is developed by the developing unit 16, and a toner image is formed on the surface of the electrophotographic photosensitive member 14 (developing step). For example, in the case of a digital electrophotographic copying machine using an organic photoconductor as the electrophotographic photoconductor 14 and using a laser beam as the exposure unit 12, the surface of the electrophotographic photoconductor 14 is negatively charged by the charging unit 10. Then, a digital latent image is formed in a dot shape by the laser beam light, and toner is applied to the portion irradiated with the laser beam light by the developing unit 16 to be visualized. In this case, a negative bias is applied to the developing unit 16. Next, a transfer member 24 such as paper is superposed on the toner image at the transfer unit 18, and a charge opposite in polarity to the toner is applied to the transfer member 24 from the back side of the transfer member 24, and the toner image is generated by electrostatic force. Is transferred to the transfer target 24 (transfer process). The transferred toner image is heated and pressed by a fixing member in the fixing unit 22 and is fused and fixed to the transfer target 24 (fixing step). On the other hand, toner remaining on the surface of the electrophotographic photoreceptor 14 without being transferred is removed by the cleaning unit 20 (cleaning step). One cycle is completed in a series of processes from charging to cleaning. In FIG. 1, the toner image is directly transferred to the transfer target 24 such as a sheet by the transfer unit 18, but may be transferred via a transfer member such as an intermediate transfer member.

  Hereinafter, the charging unit, the image carrier, the exposure unit, the developing unit, the transfer unit, the cleaning unit, and the fixing unit in the image forming apparatus 1 of FIG. 1 will be described.

(Charging means)
For example, a charging device such as a corotron as shown in FIG. 1 is used as the charging unit 10 as a charging unit, but a conductive or semiconductive charging roll may be used. A contact charger using a conductive or semiconductive charging roll may apply a direct current to the electrophotographic photosensitive member 14 or may superimpose an alternating current. For example, the charging unit 10 charges the surface of the electrophotographic photosensitive member 14 by generating a discharge in a minute space near the contact portion with the electrophotographic photosensitive member 14. Normally, it is charged to −300V or more and −1000V or less. The conductive or semiconductive charging roll may have a single layer structure or a multiple structure. Further, a mechanism for cleaning the surface of the charging roll may be provided.

(Image carrier)
The image carrier has a function of forming at least a latent image (electrostatic charge image). As the image carrier, an electrophotographic photosensitive member is preferably exemplified. The electrophotographic photoreceptor 14 has a coating film containing an organic photoreceptor or the like on the outer peripheral surface of a cylindrical conductive substrate. The coating film is a substrate in which a subbing layer and a photosensitive layer including a charge generating layer containing a charge generating material and a charge transporting layer containing a charge transporting material are formed in this order on the substrate as necessary. is there. The order of stacking the charge generation layer and the charge transport layer may be reversed. These are layered photoreceptors in which a charge generation material and a charge transport material are contained in separate layers (charge generation layer, charge transport layer), but both the charge generation material and the charge transport material are the same. A single-layer type photoreceptor included in the above layer may be used, and a laminated photoreceptor is preferable. Further, an intermediate layer may be provided between the undercoat layer and the photosensitive layer. In addition, other types of photosensitive layers such as an amorphous silicon photosensitive film may be used in addition to the organic photoreceptor.

(Exposure means)
There are no particular limitations on the exposure unit 12 that is an exposure means. For example, an optical device that can expose a light source such as semiconductor laser light, LED light, or liquid crystal shutter light on the surface of the image carrier in a desired image-like manner. Can be mentioned.

(Development means)
The developing unit 16 serving as a developing unit has a function of developing a latent image formed on the image carrier with a developer containing toner to form a toner image. Such a developing device is not particularly limited as long as it has the above-mentioned function, and can be appropriately selected according to the purpose. For example, toner for developing an electrostatic image is used using a brush, a roller, or the like. A known developing device having a function of adhering to the electrophotographic photosensitive member 14 may be used. For the electrophotographic photosensitive member 14, a DC voltage is usually used, but an AC voltage may be superimposed and used.

(Transfer means)
As the transfer unit 18 serving as a transfer unit, for example, a charge having a polarity opposite to that of the toner is applied to the transfer target 24 from the back side of the transfer target 24 as shown in FIG. A transfer roll and a transfer roll pressing device using a conductive roll or a semiconductive roll that transfers directly to the surface of the transferred body 24 via the transferred body 24 can be used. . A direct current may be applied to the transfer roll as a transfer current applied to the image carrier, or an alternating current may be applied in a superimposed manner. The transfer roll can be arbitrarily set depending on the width of the image area to be charged, the shape of the transfer charger, the opening width, the process speed (circumferential speed), and the like. Further, a single layer foam roll or the like is suitably used as a transfer roll for cost reduction. As a transfer method, a method of transferring directly to the transfer target 24 such as paper or a method of transferring to the transfer target 24 via an intermediate transfer member may be used.

  A known intermediate transfer member can be used as the intermediate transfer member. Materials used for the intermediate transfer member include polycarbonate resin (PC), polyvinylidene fluoride (PVDF), polyalkylene phthalate, PC / polyalkylene terephthalate (PAT) blend material, ethylene tetrafluoroethylene copolymer (ETFE) / PC, ETFE / PAT, PC / PAT blend materials, and the like can be mentioned. From the viewpoint of mechanical strength, an intermediate transfer belt using a thermosetting polyimide resin is preferable.

(Cleaning means)
The cleaning unit 20 serving as a cleaning unit may be appropriately selected such as one that employs a blade cleaning method, a brush cleaning method, or a roll cleaning method as long as the toner remaining on the image carrier is cleaned. Among these, it is preferable to use a cleaning blade. Examples of the material for the cleaning blade include urethane rubber, neoprene rubber, and silicone rubber. Among them, it is particularly preferable to use a polyurethane elastic body because of its excellent wear resistance. However, there may be a mode in which the cleaning unit 20 is not used when toner having high transfer efficiency is used.

(Fixing means)
The fixing unit 22 that is a fixing unit (image fixing device) fixes the toner image transferred to the transfer medium 24 by heating, pressing, or heating and pressing, and includes a fixing member. For example, a fixing device including a heating roll and a pressure roll is used.

  The toner on the paper is overheated at the fixing nip portion between the heating roll and the pressure roll, and the paper becomes difficult to be peeled off from the heating roll. The main cause is that the set temperature of the heating roll is high, or in the case of thin paper, it is easy to wind around the heating roll. As a method for preventing this, there is a method of lowering the set temperature of the heating roll, but when plain paper (about 70 gsm) and thin paper (about 50 gsm) are mixed as paper, the image quality of plain paper deteriorates. It is not an effective means. Therefore, by preliminarily curling the paper before entering the fixing nip portion downward with respect to the heating roll, the paper can be immediately pulled away from the heating roll immediately after fixing, thereby preventing paper peeling failure. Fixing and peeling performance can be improved.

  That is, in a fixing device for fixing a sheet carrying an unfixed toner image, a heating unit and a pressurizing unit are provided, and a fixing nip unit is formed in the vicinity of a fixing nip formed by the heating unit and the pressurizing unit. There is a bent sheet conveying means at the starting point up to 200 mm, and the sheet conveying means has a shape bent in the opposite direction to the heating part in the sheet conveying direction, that is, a shape bent toward the pressing part side. It is preferable. Even if the sheet conveying means is bent at a position exceeding 200 mm starting from the fixing nip, it may not be possible to prevent the peeling failure.

  FIG. 2 shows a schematic configuration of an example of a fixing device according to the present embodiment. The fixing device 3 of FIG. 2 includes a heating roll 50, a pressure roll 52, a paper conveyance path 54 that is a bent paper conveyance means, and a peeling member 56. In the fixing device 3, a sheet conveyance path that is bent in the vicinity of the fixing nip portion 58 between the heating roll 50 and the pressure roll 52 that are provided to face each other and upstream of the fixing nip portion 58 in the sheet conveyance path. 54 is provided.

  The paper 60 passes through the paper conveyance path 54 along the paper conveyance direction, and then enters the fixing nip portion 58. The toner image formed on the image surface of the paper is fixed by the heating roll 50 and the pressure roll 52. The The sheet on which the toner is fixed is peeled off from the heating roll 50 and the pressure roll 52 by the peeling member 56.

  It is preferable that the paper transport path 54 bends into a shape in which the paper 60 warps in the opposite direction with respect to the heating roll 50 before entering the fixing nip portion 58. The angle α of the paper conveyance path 54 installed before entering the fixing nip 58 is bent in the opposite direction to the heating roll 50 in the paper conveyance direction, that is, the pressure roll 52 side (left side in FIG. 2). However, it is preferable to have a shape that is bent in the range of 20 degrees or more and 70 degrees or less on the pressure roll 52 side, and more preferably a shape that is bent in the range of 30 degrees or more and 60 degrees or less. . If the angle α is less than 20 degrees or more than 70 degrees, the peelability of the paper may not be improved.

  When such a paper conveyance path 54 is used, the paper 60 enters the fixing nip portion 58 of the fixing device 3 in a state of being curled to the pressure roll 52 side (downward in FIG. 2), and therefore is wound around the heating roll 50 side. It becomes difficult to stick. If the paper is thin, it is easier to curl, so even if plain paper and thin paper are mixed, there is no need to change the set temperature of the fixing device, improving the peelability of the paper, and images with poor peel It becomes possible to suppress the occurrence of defects.

  Although FIG. 2 has been described as a roll-roll type fixing device, other fixing type fixing devices such as a belt nip method may be used.

(Transfer)
Examples of the transfer target (paper) 24 to which the toner image is transferred include plain paper, OHP sheet, and the like used in electrophotographic copying machines, printers, and the like. In order to further improve the smoothness of the image surface after fixing, it is preferable that the surface of the transfer target is as smooth as possible. For example, coated paper in which the surface of plain paper is coated with resin, art paper for printing, etc. Can be preferably used.

  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.

<Preparation of crystalline polyester resin dispersion A>
By mixing in a flask at a ratio of 52 mol% of pentanediol, 48 mol% of succinic acid and 0.08 mol% of dibutyltin oxide as a catalyst, the mixture is heated to 220 ° C. in a reduced pressure atmosphere and subjected to a dehydration condensation reaction for 6 hours. Polyester resin A was obtained. Next, 80 g of this crystalline polyester resin A and 720 g of deionized water were placed in a stainless beaker, placed in a warm bath, and heated to 55 ° C. When the crystalline polyester resin A was melted, the mixture was stirred at 7000 rpm using a homogenizer (manufactured by IKA: Ultra Turrax T50). Subsequently, the pH was adjusted to 7.0, and then emulsified and dispersed while dropping 1.8 parts by weight of an anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd., Neogen RK, 20% by weight). The particle size was measured using Microtrac (manufactured by Nikkiso Co., Ltd., Microtrac UPA9340) to obtain a crystalline polyester resin dispersion A (solid content 10% by weight) having a volume average particle size of 0.146 μm. The obtained crystalline polyester resin A had a melting point Tmc of 32 ° C.

  The crystalline polyester resin A has a melting point of 10 ° C./min from room temperature to 150 ° C. using a differential scanning calorimeter (manufactured by Shimadzu Corporation: DSC60, with automatic tangential treatment system) according to ASTM D3418-8. It was measured under the conditions of and obtained from the maximum peak.

  The weight average molecular weight (Mw) of the crystalline polyester resin A determined by molecular weight measurement (polystyrene conversion) by gel permeation chromatography (GPC) was 16,200.

  The acid value of the crystalline polyester resin A determined from a color reaction with phenolphthalein was 9.6 mgKOH / g.

<Preparation of crystalline polyester resin dispersion B>
A crystalline polyester resin dispersion B (volume average particle size 0.171 μm) was prepared in the same manner as dispersion A except that the alcohol component was butanediol, the acid component was sebacic acid, and the temperature of the warm bath was changed to 80 ° C. 10% by weight of solid content) was obtained. The obtained crystalline polyester resin B had a melting point Tmc of 68 ° C. The crystalline polyester resin B had a weight average molecular weight (Mw) of 14600 and an acid value AVc of 10.8 mgKOH / g.

<Preparation of crystalline polyester resin dispersion C>
A crystalline polyester resin dispersion C (solid content 10% by weight) was obtained in the same manner as the crystalline polyester resin dispersion A except that the amount of succinic acid was 16 mol%. The obtained crystalline polyester resin C had a melting point Tmc of 28 ° C. The crystalline polyester resin C had a weight average molecular weight (Mw) of 13,200 and an acid value AVc of 5.0 mgKOH / g.

<Preparation of crystalline polyester resin dispersion D>
A crystalline polyester resin dispersion D (solid content 10% by weight) was obtained in the same manner as the crystalline polyester resin dispersion A except that the dehydration condensation reaction time was set to 9 hours. The obtained crystalline polyester resin D had a melting point Tmc of 45 ° C. The crystalline polyester resin D had a weight average molecular weight (Mw) of 19,800 and an acid value AVc of 12.0 mgKOH / g.

<Preparation of crystalline polyester resin dispersion E>
A crystalline polyester resin dispersion E (solid content 10% by weight) was obtained in the same manner as in the crystalline polyester resin dispersion A except that the amount of succinic acid was changed to 52 mol%. The resulting crystalline polyester resin E had a melting point Tmc of 25 ° C. The crystalline polyester resin E had a weight average molecular weight (Mw) of 12,800 and an acid value AVc of 10.2 mgKOH / g.

<Preparation of crystalline polyester resin dispersion F>
A crystalline polyester resin dispersion F (solid content 10% by weight) was obtained in the same manner as the crystalline polyester resin dispersion A except that the dehydration condensation reaction time was 11 hours and the amount of succinic acid was 41 mol%. The resulting crystalline polyester resin F had a melting point Tmc of 50 ° C. The crystalline polyester resin F had a weight average molecular weight (Mw) of 20400 and an acid value AVc of 8.3 mgKOH / g.

<Preparation of crystalline polyester resin dispersion G>
The crystalline polyester resin dispersion G (the same as the crystalline polyester resin dispersion A except that the heating temperature under reduced pressure was 200 ° C., the dehydration condensation reaction time was 4 hours, and the amount of succinic acid was 39 mol%. 10% by weight of solid content) was obtained. The obtained crystalline polyester resin G had a melting point Tmc of 20 ° C. The crystalline polyester resin G had a weight average molecular weight (Mw) of 10400 and an acid value AVc of 7.7 mgKOH / g.

<Preparation of crystalline polyester resin dispersion H>
The crystalline polyester resin dispersion H (except that the heating temperature in a reduced pressure atmosphere is 250 ° C., the dehydration condensation reaction time is 10 hours, and the amount of succinic acid is 52 mol% is the same as the crystalline polyester resin dispersion H ( 10% by weight of solid content) was obtained. The obtained crystalline polyester resin H had a melting point Tmc of 55 ° C. The crystalline polyester resin H had a weight average molecular weight (Mw) of 22,200 and an acid value AVc of 10.3 mgKOH / g.

<Preparation of Amorphous Polyester Resin Dispersion I>
In a reaction vessel equipped with a stirrer, thermometer, condenser and nitrogen gas inlet tube, dimethyl terephthalate 23 mol%, isophthalic acid 30 mol%, dodecenyl succinic anhydride 15 mol%, trimellitic anhydride 9 mol%, bisphenol A ethylene oxide The adduct was added at a rate of 5 mol% and bisphenol A propylene oxide adduct 45 mol%, and the reaction vessel was replaced with dry nitrogen gas, and then added as a catalyst at a rate of 0.06 mol% of dibutyltin oxide, and under a nitrogen gas stream, 190 The mixture was allowed to stir at 9 ° C. for 9 hours, and the temperature was further raised to 270 ° C. and stirred for 5.0 hours. Then, the reaction vessel was depressurized to 10.0 mmHg and stirred for 0.5 hours under reduced pressure. Crystalline polyester resin I was obtained. The obtained amorphous polyester resin I had a glass transition point (Tg) of 71 ° C. The weight average molecular weight (Mw) was 41300, and the acid value AVA of the resin was 26.8 mgKOH / g.

  The glass transition point Tg of the amorphous resin was determined by the ASTM method using a differential scanning calorimeter (manufactured by Shimadzu Corporation: DSC60, with an automatic tangential processing system).

Amorphous polyester resin I obtained: 160 parts by weight, ion exchange water: 640 parts by weight, and anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd., Neogen RK, 20% by weight) 8.0 parts by weight Preliminarily dispersed and adjusted to pH 7.5 with aqueous ammonia. Next, using a disperser in which Cavitron CD1010 (manufactured by Eurotech Co., Ltd.) is remodeled into a high temperature and high pressure type, the rotor is rotated at a speed of 60 Hz, the pressure is 5 kg / cm ² , and the heating temperature by the heat exchanger is 140 ° C. To obtain an amorphous polyester resin dispersion I (solid content 20% by weight) having a volume average particle size of 0.168 μm.

<Preparation of Amorphous Polyester Resin Dispersion Liquid J>
In a reaction vessel equipped with a stirrer, thermometer, condenser and nitrogen gas inlet tube, dimethyl terephthalate 35 mol%, isophthalic acid 10 mol%, dodecenyl succinic anhydride 3 mol%, trimellitic anhydride 2 mol%, bisphenol A ethylene oxide The adduct was added at a rate of 45 mol% and bisphenol A propylene oxide adduct at a rate of 5 mol%, and the reaction vessel was replaced with dry nitrogen gas, and then added as a catalyst at a rate of 0.06 mol% of dibutyltin oxide. The mixture was allowed to stir at 7 ° C. for 7 hours, and the temperature was further raised to 250 ° C. for 3.0 hours. Crystalline polyester resin J was obtained. The obtained amorphous polyester resin J had a glass transition point (Tg) of 48 ° C. The weight average molecular weight (Mw) was 25800, and the acid value of the resin was 13.7 mgKOH / g.

  The obtained amorphous polyester resin dispersion J was prepared in the same manner as the amorphous polyester resin dispersion I to obtain an amorphous polyester resin dispersion J having a volume average particle size of 0.154 μm (solid content 20% by weight). )

<Preparation of amorphous polyester resin dispersion K>
Amorphous polyester resin dispersion K was prepared in the same manner as in Preparation of Amorphous Polyester Resin Dispersion I, except that dodecenyl succinic anhydride was 9 mol% and the reaction time at 270 ° C. in a nitrogen gas stream was 5.5 hours. Got. The glass transition point (Tg) of the obtained amorphous polyester resin K was 80 ° C. The weight average molecular weight (Mw) was 43800, and the acid value AVA of the resin was 17.0 mgKOH / g.

<Preparation of amorphous polyester resin dispersion L>
Amorphous polyester resin dispersion L was prepared in the same manner as in Preparation of Amorphous Polyester Resin Dispersion I, except that dodecenyl succinic anhydride was 23 mol% and the reaction time at 270 ° C. in a nitrogen gas stream was 6.5 hours. Got. The glass transition point (Tg) of the obtained amorphous polyester resin L was 90 ° C. The weight average molecular weight (Mw) was 48900, and the acid value AVA of the resin was 41.0 mgKOH / g.

<Preparation of amorphous polyester resin dispersion M>
Amorphous polyester resin dispersion was carried out in the same manner as in Preparation of Amorphous Polyester Resin Dispersion I, except that dodecenyl succinic anhydride was 10.5 mol% and the reaction time at 270 ° C. in a nitrogen gas stream was 4.5 hours. A liquid M was obtained. The resulting amorphous polyester resin M had a glass transition point (Tg) of 60 ° C. The weight average molecular weight (Mw) was 37700, and the acid value Ava of the resin was 20.3 mgKOH / g.

<Preparation of amorphous polyester resin dispersion N>
Amorphous polyester resin dispersion was carried out in the same manner as in the preparation of Amorphous Polyester Resin Dispersion I, except that dodecenyl succinic anhydride was 8.5 mol% and the reaction time at 270 ° C. in a nitrogen gas stream was 4.5 hours. Liquid N was obtained. The obtained amorphous polyester resin N had a glass transition point (Tg) of 62 ° C. The weight average molecular weight (Mw) was 38100, and the acid value AVA of the resin was 15.0 mgKOH / g.

<Preparation of amorphous polyester resin dispersion O>
Amorphous polyester resin dispersion O was prepared in the same manner as in Preparation of Amorphous Polyester Resin Dispersion I, except that dodecenyl succinic anhydride was 27.5 mol% and the reaction time at 270 ° C. in a nitrogen gas stream was 9 hours. Got. The obtained amorphous polyester resin O had a glass transition point (Tg) of 68 ° C. The weight average molecular weight (Mw) was 39800, and the acid value AVA of the resin was 50.0 mgKOH / g.

<Preparation of amorphous polyester resin dispersion P>
Amorphous polyester resin dispersion P was prepared in the same manner as in the preparation of amorphous polyester resin dispersion I except that dodecenyl succinic anhydride was 6.5 mol% and the reaction time at 270 ° C. in a nitrogen gas stream was 9 hours. Got. The obtained amorphous polyester resin P had a glass transition point (Tg) of 70 ° C. The weight average molecular weight (Mw) was 41100, and the acid value AVA of the resin was 12.0 mgKOH / g.

<Preparation of amorphous polyester resin dispersion Q>
Amorphous polyester resin dispersion was carried out in the same manner as in Preparation of Amorphous Polyester Resin Dispersion I, except that dodecenyl succinic anhydride was 10.5 mol% and the reaction time at 270 ° C. in a nitrogen gas stream was 3.5 hours. Liquid Q was obtained. The obtained amorphous polyester resin Q had a glass transition point (Tg) of 55 ° C. The weight average molecular weight (Mw) was 32100, and the acid value AVA of the resin was 21.1 mgKOH / g.

<Preparation of amorphous polyester resin dispersion R>
The same procedure as in Preparation of Amorphous Polyester Resin Dispersion I was performed, except that dodecenyl succinic anhydride was 10.5 mol%, the reaction temperature 270 ° C. in a nitrogen gas stream was 280 ° C., and the reaction time was 8 hours. A crystalline polyester resin dispersion R was obtained. The obtained amorphous polyester resin R had a glass transition point (Tg) of 95 ° C. The weight average molecular weight (Mw) was 50600, and the acid value AVA of the resin was 22.4 mgKOH / g.

<Preparation of amorphous polyester resin dispersion S>
Amorphous polyester resin dispersion was carried out in the same manner as in Preparation of Amorphous Polyester Resin Dispersion I, except that dodecenyl succinic anhydride was changed to 29.0 mol% and the reaction time at 270 ° C. in a nitrogen gas stream was changed to 5.0 hours. Liquid S was obtained. The obtained amorphous polyester resin S had a glass transition point (Tg) of 72 ° C. The weight average molecular weight (Mw) was 41400, and the acid value AVA of the resin was 55.0 mgKOH / g.

<Preparation of colorant particle dispersion>
Phthalocyanine pigment (Daiichi Seika Co., Ltd., PVFASTBLUE) 90 parts by weight Anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd., Neogen SC) 10 parts by weight Ion-exchanged water 260 parts by weight Dispersion treatment was performed using an optimizer HJP-25008 (manufactured by Sugino Machine Co., Ltd.) set at a pressure of 196 MPa to prepare a colorant particle dispersion (colorant concentration 25% by weight). The number average particle diameter of the colorant in the colorant dispersion was 125 nm.

<Preparation of release agent dispersion A>
Paraffin wax (Nippon Seiwa Co., Ltd., HNP9, melting point 77 ° C.) 50 parts by weight Anionic surfactant (Daiichi Kogyo Seiyaku, Neogen SC) 7.5 parts by weight Ion-exchanged water 200 parts by weight After heating to 0 ° C. and dispersing using a homogenizer (manufactured by IKA: Ultra Turrax T50), the dispersion is treated with a Menton Gorin high-pressure homogenizer (Gorin), and a release agent dispersion A having a volume average particle size of 220 nm. (Release agent concentration 20% by weight) was prepared.

Example 1
<Preparation of Toner Particle A>
Crystalline polyester resin dispersion A 300 parts by weight Amorphous polyester resin dispersion I 100 parts by weight Colorant particle dispersion 30 parts by weight Release agent dispersion A 35 parts by weight Temperature of 10 ° C. in a 2 L cylindrical stainless steel container The adjusted ratio of the raw materials shown above was added, and the mixture was dispersed and mixed for 10 minutes while applying a shearing force at 4000 rpm with a homogenizer (manufactured by IKA: Ultra Turrax T50) while maintaining the liquid temperature at 10 ° C. Next, 1.8 parts by weight of a 10% nitric acid aqueous solution of a flocculant (manufactured by Asada Chemical Co., Ltd., polyaluminum chloride) is gradually added dropwise to the raw material solids, and the rotation speed of the homogenizer is set to 5000 rpm for 15 minutes. Dispersed and mixed to obtain a raw material dispersion. Thereafter, the raw material dispersion 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 40 ° C. At this time, the pH of the raw material dispersion was controlled in the range of 3.2 to 3.8 with 0.3N nitric acid or 1N sodium hydroxide aqueous solution. The agglomerated particles were formed by maintaining the above pH range for 0.5 hour. The toner particle diameter was confirmed to be 3.9 μm. An additional 40 parts by weight of amorphous polyester resin dispersion I was added and held for another 0.5 hours.

  The volume average particle diameter of the aggregated particles measured using Multisizer II (aperture diameter: 50 μm, manufactured by Beckman Coulter, Inc.) was 4.3 μm. Thereafter, in order to fuse the aggregated particles, an aqueous NaOH solution was dropped to raise the pH to 7.5, and then the temperature was raised to 95 ° C. Thereafter, the particles were fused for 3 hours, and after confirming that the aggregated particles were fused with an optical microscope, the particles were cooled at a temperature drop rate of 0.5 ° C./min.

  Thereafter, it was sieved with a 20 μm mesh. Next, a solid-liquid separation step was performed by filtration, and the resultant was dispersed in 20 ° C./20 times the amount of ion-exchanged water with respect to the toner solid content, followed by stirring for 20 minutes and filtration. This process was repeated 5 times. Thereafter, drying was performed with a freeze vacuum dryer, and toner particles A were obtained. The obtained toner particles A had a volume average particle diameter (D50v) of 4.2 μm.

<Production of developer>
Ferrite particles (volume average particle size 35 μm) 100 parts by weight Toluene 15 parts by weight Styrene-methyl methacrylate copolymer 2 parts by weight Carbon black (R330, manufactured by Cabot Corporation) 0.18 parts by weight Quaternary ammonium salt charge control agent (P51) 15 parts by weight First, all the components except the ferrite particles were stirred with a stirrer for 10 minutes to prepare a dispersed coating layer forming solution. Next, the coating layer forming solution and the ferrite particles are put into a vacuum degassing kneader, stirred at 60 ° C. for 30 minutes, further depressurized while being heated, degassed, and dried to dry the carrier (1 ) The carrier (1) thus prepared was mixed with toner to obtain developer A.

<Method for Measuring Content of Crystalline Resin in Toner>
The content of the crystalline resin in the toner was determined by using a differential scanning calorimeter (manufactured by Shimadzu Corporation: DSC60, with an automatic tangential processing system) and absorbing the same weight of crystalline resin from the endothermic amount in the melting point region by the ASTM method. The amount of heat was determined as 100.

<Measuring Method of Melting Point Tmc of Crystalline Resin in Toner and Glass Transition Point Tg of Amorphous Resin>
The melting point Tmc of the crystalline resin in the toner and the glass transition point Tg of the amorphous resin are measured by the ASTM method using a differential scanning calorimeter (manufactured by Shimadzu Corporation: DSC60, with an automatic tangential treatment system). Was determined by

<Method for Measuring Acid Value AVc of Crystalline Resin and Toner Acid Value AVa of Amorphous Resin>
First, the acid value of the toner particles is measured. 0.1 g of toner particles were precisely weighed and dissolved in 80 mL of tetrahydrofuran. Phenolphthalein was added as an indicator, titrated with a 0.1N KOH ethanol solution, and the acid value was calculated from the amount of the 0.1N KOH ethanol solution used with the point where the color persisted for 30 seconds. As the acid value AVc of the crystalline resin in the toner, the crystalline resin was melted and separated at 60 ° C. after fixing to OHP, and the acid value AVc was calculated in the same manner as in the toner. The acid value AVa of the amorphous resin was calculated from the acid value of the whole toner, the content of the crystalline resin, and the acid value.

<Evaluation of toner shape>
The toner shape factor SF1 and the major axis diameter of the toner particles were determined as described above. When the major axis diameter of the toner particles was measured in the same manner, particles having a major axis diameter of 6.7 μm or more and 8.0 μm or less and SF1 of 155 or more were 0.8 pop% in the toner particles A.

<Shell layer thickness measurement>
After toner preparation, the cross-section of 50 toner particles was confirmed with a transmission electron microscope TEM device (manufactured by JEOL Ltd. (JEOL, Ltd.), JEM-1010 electron microscope), and the thickness of the shell layer at any three points of each particle Was determined from the average value. The toner particle A has a thickness of 0.7 μm.

<Evaluation of low-temperature fixability>
The low-temperature fixability of the toner is adjusted to 6.0 g / cm ² on C2 paper (Fuji Xerox, basis weight 70 gsm), which is a plain paper, using a modified DocuCenter Color a450 manufactured by Fuji Xerox, and fixed at 100 ° C. (Process speed was 90 mm / sec). After fixing the fixed image with cello tape (registered trademark) (15 mm) manufactured by Nichiban Co., Ltd., the fixed image was peeled off to confirm whether the fixed image was missing. Evaluation was made according to the following criteria.
○: No traces are observed on the tape or the fixed image. Δ: Traces remain on the fixed image but no sticking on the tape. X: Defects are observed on the fixed image.

<Evaluation of fine line reproducibility>
Using a modified DocuCentreColor a450 machine manufactured by Fuji Xerox, the toner fine line reproducibility is 1400 nm resolution at 120 ° C with a resolution of 2400 dpi on plain paper C2 paper (Fuji Xerox, basis weight 70 gsm). The fixed image obtained was taken into a Luzex image analyzer through a video camera from a 100 × optical microscope image, and evaluated according to the following criteria from the distribution of the shape factor SF-2 indicating the perimeter of each of the 40 fine lines. .
◎: MAX / MIN is 1.01 or less ○: MAX / MIN is 1.04 or less Δ: MAX / MIN is less than 1.10 ×: MAX / MIN is 1.10 or more

  The results are summarized in Table 1.

(Example 2)
A toner was prepared in the same manner as in Example 1 except that the crystalline resin dispersion C was used instead of the crystalline resin dispersion A, and the amorphous resin dispersion K was used instead of the amorphous resin dispersion I. The results are shown in Table 1.

(Example 3)
A toner was prepared in the same manner as in Example 1 except that the crystalline resin dispersion D was used instead of the crystalline resin dispersion A, and the amorphous resin dispersion L was used instead of the amorphous resin dispersion I. The results are shown in Table 1.

Example 4
A toner was prepared in the same manner as in Example 1 except that the crystalline resin dispersion E was used instead of the crystalline resin dispersion A. The results are shown in Table 1.

(Example 5)
A toner was prepared in the same manner as in Example 1 except that the crystalline resin dispersion F was used instead of the crystalline resin dispersion A. The results are shown in Table 1.

(Example 6)
A toner was prepared in the same manner as in Example 1 except that the amorphous resin dispersion M was used instead of the amorphous resin dispersion I. The results are shown in Table 1.

(Example 7)
A toner is prepared in the same manner as in Example 1 except that the crystalline resin dispersion C is used instead of the crystalline resin dispersion A, and the amorphous resin dispersion N is used instead of the amorphous resin dispersion I. did. The results are shown in Table 1.

(Example 8)
A toner was prepared in the same manner as in Example 1 except that the amorphous resin dispersion O was used instead of the amorphous resin dispersion I. The results are shown in Table 1.

Example 9
A toner was prepared in the same manner as in Example 1 except that the amorphous resin dispersion K was used in place of the amorphous resin dispersion I. The results are shown in Table 1.

(Comparative Example 1)
A toner was prepared in the same manner as in Example 1 except that the crystalline resin dispersion B was used instead of the crystalline resin dispersion A. The results are shown in Table 2.

(Comparative Example 2)
A toner was prepared in the same manner as in Example 1 except that the amorphous resin dispersion P was used instead of the amorphous resin dispersion I. The results are shown in Table 2.

(Comparative Example 3)
A toner was prepared in the same manner as in Example 1 except that the crystalline resin dispersion G was used instead of the crystalline resin dispersion A. The results are shown in Table 2.

(Comparative Example 4)
A toner is prepared in the same manner as in Example 1 except that the crystalline resin dispersion H is used instead of the crystalline resin dispersion A, and the amorphous resin dispersion J is used instead of the amorphous resin dispersion I. did. The results are shown in Table 2.

(Comparative Example 5)
A toner was prepared in the same manner as in Example 1 except that the amorphous resin dispersion Q was used instead of the amorphous resin dispersion I. The results are shown in Table 2.

(Comparative Example 6)
A toner was prepared in the same manner as in Example 1 except that the amorphous resin dispersion R was used instead of the amorphous resin dispersion I. The results are shown in Table 2.

(Comparative Example 7)
A toner was prepared in the same manner as in Example 1 except that the amorphous resin dispersion S was used instead of the amorphous resin dispersion I. The results are shown in Table 2.

  Thus, by using the toners of Examples 1 to 9, it is possible to prevent fusion between particles even when coalescence is performed at a temperature equal to or higher than the melting point Tmc of the low melting crystalline resin in the aggregation and coalescence process. It had a relatively uniform particle size and shape, and good low-temperature fixability and fine line reproducibility.

(Example 10)
Using the toner of Example 1, an image forming apparatus including the fixing device shown in FIG. 2 was used. The results are shown in Table 1. In the configuration of the fixing device of FIG. 2, the paper conveyance path is bent in a shape in which the paper warps in the opposite direction with respect to the heating roll before entering the fixing nip portion. The angle α of the sheet conveyance path is 20 degrees, 30 degrees, 45 degrees, 60 degrees, 70 degrees, 90 degrees on the pressure roll side (left side in FIG. 2), and the linear direction (see FIG. 3). ) A total of 7 types of paper transport paths are used, and each A4 sheet of plain paper C2 paper (Fuji Xerox, basis weight 70 gsm) and thin paper ST paper (Fuji Xerox, basis weight 52 gsm) are fed horizontally. Then, the image when the temperature of the heating roll was fixed from 160 ° C. to 200 ° C. every 10 ° C. was confirmed and evaluated according to the following criteria. The results are shown in Table 3.

◎: No problem ○: Minor image irregularity △: Image irregularity ×: Paper jam occurred

  As shown in Table 1, the low-temperature fixability and fine line reproducibility were good. Further, as shown in Table 3, when using a paper conveyance path having a shape in which the paper warps in the opposite direction with respect to the heating roll as compared with the case where the paper is conveyed from the conventional linear direction, image unevenness is obtained. As a result, the paper peelability was improved by 10 ° C. When the angle α was 45 degrees, the same effect as 30 degrees and 60 degrees was obtained. Further, when the angle α was 20 degrees and 70 degrees, it was equivalent to the linear direction. The paper jam at the angle α = 90 degrees was a paper jam just before the fixing device (the paper did not reach the fixing nip).

1 is a schematic configuration diagram illustrating an example of an image forming apparatus according to an embodiment of the present invention. 1 is a schematic configuration diagram illustrating an example of a fixing device in an image forming apparatus according to an embodiment of the present invention. It is a figure which shows the conveyance direction of the linear direction of the paper in Example 10 of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Image forming apparatus, 3 fixing device, 10 charging part, 12 exposure part, 14 electrophotographic photosensitive member, 16 developing part, 18 transfer part, 20 cleaning part, 22 fixing part, 24 transferred object, 50 heating roll, 52 heating Pressure roll, 54 paper transport path, 56 peeling member, 58 fixing nip, 60 paper.

Claims (7)

Having core particles containing a crystalline resin and a shell layer containing an amorphous resin;
The content of the crystalline resin in the toner is 15 wt% or more and 65 wt% or less,
The melting point Tmc of the crystalline resin is 25 ° C. or more and 50 ° C. or less, and the glass transition point Tg of the amorphous resin is 60 ° C. or more and 90 ° C. or less,
An electrostatic charge image, wherein the acid value AVa of the amorphous resin is 15 mg KOH / g or more and 50 mg KOH / g or less, and the acid value of the crystalline resin is AVc, AVa> AVc. Development toner. The electrostatic image developing toner according to claim 1,
When the volume average particle diameter D50v of the toner is α, the content in the toner of particles having a major axis diameter of 1.6α or more and 1.9α or less and a shape factor SF1 of 155 or more is 4.0 pops. % Or less of the toner for developing electrostatic images. The toner for developing an electrostatic charge image according to claim 1 or 2,
A toner for developing an electrostatic charge image, wherein a difference AVa-AVc between an acid value AVa of the amorphous resin and an acid value AVc of the crystalline resin is 10 or more. The electrostatic charge image developing toner according to any one of claims 1 to 3,
A toner for developing an electrostatic charge image, wherein the toner has a volume average particle diameter D50v of from 1.5 μm to 5.0 μm. An electrostatic charge image developing toner according to any one of claims 1 to 4,
An electrostatic charge image developing toner, wherein the shell layer has an average cross-sectional thickness of 0.2 μm or more and 1.5 μm or less.   An electrostatic charge image developing developer comprising the electrostatic charge image developing toner according to claim 1 and a carrier. An image carrier, a latent image forming unit that forms an electrostatic latent image on the surface of the image carrier, a developing unit that develops the electrostatic latent image using a developer to form a toner image, and the development A transfer means for transferring the toner image thus transferred to a transfer medium,
The image forming apparatus according to claim 6, wherein the developer is a developer for developing an electrostatic image according to claim 6.

Images