JP5223548B2 - Toner for developing electrostatic image, developer for developing electrostatic image, image forming method and image forming apparatus - Google Patents

Description

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

  As a means capable of intentionally controlling the toner shape and the surface structure in response to the demand for higher image quality, a method for producing an electrophotographic toner by a wet process has been proposed. There is an agglomeration method. In preparation of a toner by a polymerization method such as a wet method, in order to obtain sufficient charging characteristics as an electrostatic charge image developing toner (hereinafter also referred to as “electrophotographic toner” or simply “toner”), solid-liquid separation such as filtration, It is necessary to go through a toner cleaning and drying process.

  On the other hand, in electrophotography, from the viewpoint of energy saving, there is a strong demand to provide low-temperature fixability for the purpose of reducing energy consumption in copying machines, laser printers, and the like. As a means for lowering the fixing temperature of the toner, it is common to use a binder resin having a low glass transition temperature. However, if a binder resin having a low glass transition temperature is used, the toner can be blocked or stored. However, even if the glass transition temperature is lowered, there is a limit. In addition, when drying is performed via a temperature higher than the glass transition temperature, the toner may be fused to a dryer wall surface or the like, which may cause difficulty in yield and continuous operability.

  In order to realize such low-temperature fixability, it has been proposed to use a crystalline resin as a binder resin (see, for example, Patent Document 1). In addition, a plurality of binder resins including a crystalline polyester resin are used as the binder resin, a proposal of a toner excellent in color reproducibility and transparency (see, for example, Patent Document 2), and the strength of a toner including a crystalline polyester resin. Proposal of viscoelasticity and surface element amount for improvement (for example, see Patent Documents 3 and 4), Proposal of toner structure including crystalline polyester resin for improving fixing performance (for example, see Patent Document 5), Proposal for biasing the internal structure of the toner for controlling the adhesion of the toner to the photoreceptor (see, for example, Patent Document 6), Proposal for controlling the absorption peak temperature of the DSC for maintaining charging properties (for example, patents) Reference 7), proposals for specifying GPC elution to improve filming (see, for example, Patent Document 8), crystalline polyester resin for maintaining image gloss stably, amorphous polyester The proposal of the regulation of the catalyst type of the reester resin (for example, see Patent Document 9) has been made.

JP 2007-193069 A JP 2007-199300 A JP 2008-15244 A JP 2008-15333 A JP 2008-33057 A JP 2008-64859 A JP 2008-116613 A JP 2008-139647 A JP 2008-191260 A

  The present invention relates to a toner for developing an electrostatic charge image, in which a low-temperature crystalline resin is mixed with a binder resin to ensure low-temperature fixability of the toner, and toner breakage is suppressed even in a high-speed machine and transferability is maintained. It is another object of the present invention to provide a developer for developing an electrostatic image, an image forming method, and an image forming apparatus.

  The present invention is as follows.

  (1) An electrostatic image developing toner having core particles containing a crystalline polyester resin and a release agent, and a shell layer containing an amorphous polyester resin, and having at least one kind of inorganic fine particles added externally. The melting point Tm of the crystalline polyester resin is 25 ° C. or more and 50 ° C. or less, the content of the crystalline polyester resin is 5% by mass or more and 20% by mass or less, and the average particle size of the inorganic fine particles is The toner for developing an electrostatic image having a thickness of 80 nm to 300 nm.

  (2) An electrostatic charge image developing developer comprising the electrostatic charge image developing toner described in (1) above and a carrier.

  (3) The step of charging the image carrier, the step of forming a latent image on the image carrier, and the latent image on the latent image carrier using the developer for developing an electrostatic image described in (2) above. Developing, a primary transfer step of transferring the developed toner image onto the intermediate transfer member, a secondary transfer step of transferring the toner image transferred to the intermediate transfer member to a recording medium, and the toner An image forming method including a step of fixing an image by heat and pressure.

  (4) an image carrier, a charging device for charging the image carrier, an exposure device for forming an electrostatic latent image on the image carrier charged by the charging device, and an electrostatic on the image carrier A developing device that forms a latent image into a toner image, a primary transfer device that transfers the toner image to an intermediate transfer member, and a secondary transfer device that transfers the toner image transferred to the intermediate transfer member to a recording medium; And the toner for forming the toner image is the toner described in (1) above.

  According to the first aspect of the present invention, when the crystalline polyester resin having a melting point Tm of 25 ° C. or more and 50 ° C. or less is contained in the toner at 5% by mass or more and 20% by mass or less, at the time of stirring in the developing machine, For example, destruction of toner is suppressed even under high stress when agitated in a high-speed developing machine. Further, for example, even when the temperature inside the developing machine is increased by stirring and the crystalline polyester resin contained in the core particles in the toner is exposed on the toner surface, inorganic particles having an average particle diameter of 80 nm or more and 300 nm or less are formed on the toner surface. By externally adding, the degree of exposure of the crystalline polyester resin to the toner surface is finally suppressed, and the transferability of the toner is maintained.

  According to the second aspect of the present invention, the melting point Tm of the crystalline polyester resin is 25 ° C. or more and 50 ° C. or less, the content of the crystalline resin is 5% by mass or more and 20% by mass or less, and the toner surface A developer having a toner and a carrier having an average particle size of inorganic fine particles externally added to 80 nm and 300 nm or less is caused by stress on the toner during stirring in the developing machine when used in an image forming apparatus. Destruction is suppressed. Further, for example, even if the temperature inside the developing machine rises due to stirring and the crystalline polyester resin contained in the core particles in the toner is exposed on the toner surface, the inorganic particles having the above particle diameter are externally added to the toner surface. As a result, the degree of exposure of the crystalline polyester resin to the toner surface is finally suppressed, and the transferability of the developer is maintained.

  According to the third aspect of the present invention, when image formation is performed using the image forming apparatus, the melting point Tm of the crystalline polyester resin contained in the toner in the developer is 25 ° C. or more and 50 ° C. or less, and Since the content of the crystalline resin is 5% by mass or more and 20% by mass or less and the average particle size of the inorganic fine particles externally added to the toner surface is 80 nm or more and 300 nm or less, it is caused by stress during stirring in the developing machine. For example, even if the crystalline polyester resin contained in the core particles in the toner is exposed to the toner surface due to an increase in the temperature inside the developing machine due to stirring, the toner is finally externally added to the toner surface. Further, the inorganic particles having a specific particle size suppress the degree of exposure of the crystalline polyester resin to the toner surface, and maintain the transferability of the developer.

  According to the invention of claim 4, when used in an image forming apparatus, the melting point Tm of the crystalline polyester resin contained in the toner is 25 ° C. or more and 50 ° C. or less, and the content of the crystalline resin is 5 mass. % And 20% by mass or less, and the average particle size of the inorganic fine particles externally added to the toner surface is 80 nm or more and 300 nm or less, so that destruction of the toner due to stress during stirring in the developing machine is suppressed. Even if the crystalline polyester resin contained in the core particles in the toner is exposed on the toner surface due to an increase in the temperature inside the developing machine due to stirring, the inorganic particles having a specific particle size finally added to the toner surface may cause the toner The degree of exposure of the crystalline polyester resin to the surface is suppressed, and the transferability of the developer is maintained.

<Toner for electrostatic image development>
The toner for developing an electrostatic charge image according to the present embodiment (hereinafter sometimes abbreviated as “toner”) includes core particles including at least a crystalline polyester resin and a release agent, and a shell layer including an amorphous polyester resin. A toner for developing electrostatic images, to which at least one kind of inorganic fine particles is externally added, wherein the crystalline polyester resin has a melting point Tm of 25 ° C. or more and 50 ° C. or less, The content is 5% by mass or more and 20% by mass or less, and the average particle size of the inorganic fine particles is 80 nm or more and 300 nm or less.

  Toner having low-temperature fixability is generally weak against stress. For example, a boundary between a crystalline polyester resin and an amorphous polyester resin contained in the toner when used under a high stress condition such as in a high-speed developing machine. Therefore, cracks and the like are likely to occur, which may cause toner cracks. However, by using a crystalline polyester resin having a melting point Tm of 25 ° C. or more and 50 ° C. or less for the toner of the present embodiment, the role of the crystalline polyester resin to buffer against impacts even in a stirred developing machine. And the cracks described above are prevented. On the other hand, the internal temperature of the developing machine rises due to stirring, and the crystalline polyester resin is easily exposed on the toner surface, but inorganic fine particles having a larger diameter than conventional inorganic particles for external addition of 80 nm to 300 nm are used as external additives. By doing so, the degree of exposure of the crystalline polyester resin to the toner surface is finally suppressed, and the transferability is maintained.

  When the melting point Tm of the crystalline polyester resin contained in the toner in the present embodiment is less than 25 ° C., the crystalline polyester resin is softened from the normal temperature, and is contained in the toner core particles due to the stirring stress in the developing machine. The exposure of the crystalline polyester resin to the toner surface becomes too remarkable, the charge is lowered, and stains in the developing machine occur. On the other hand, when the melting point Tm of the crystalline polyester resin contained in the toner exceeds 50 ° C., the crystalline polyester resin in the toner cannot exert a buffering action, for example, due to stirring stress by a high-speed developing machine. As a result, the toner is destroyed, and as a result, the entire machine including the developing machine is contaminated.

  When the content of the crystalline polyester resin contained in the toner in the present embodiment is less than 5% by mass, the buffer against the agitation stress by the crystalline polyester resin is insufficient, the toner is destroyed, and the inside of the machine becomes dirty. There is. Further, when the content of the crystalline polyester resin contained in the toner exceeds 20% by mass, the softened portion in the toner increases with the increase in the developing machine temperature by stirring, and the crystalline polyester on the toner surface is increased. Since the exposure ratio of the resin is larger than that at normal temperature, the transfer efficiency may be reduced.

  A more preferable content of the crystalline polyester resin is 5% by mass or more and 105% by mass or less from the viewpoint of achieving both in-machine dirt and transferability.

  In the toner according to the present exemplary embodiment, when the average particle size of the inorganic fine particles externally added to the toner surface is less than 80 nm, the crystalline polyester resin inside the toner that has been stressed by stirring in the developing machine is exposed on the toner surface. In this case, the externally added inorganic particles are buried in the softened crystalline polyester resin portion, and the embedding of the inorganic fine particles becomes intense due to this stirring stress. . On the other hand, when the average particle diameter of the inorganic fine particles exceeds 300 nm, the adhesion between the toner particle surface and the externally added inorganic fine particles becomes weak, and as a result, the externally added inorganic particles are dispersed and held near the toner surface during toner preparation. In addition, externally added inorganic fine particles are likely to be detached from the toner surface due to stirring stress of a developing machine. For example, when the crystalline polyester resin is exposed on the toner surface as the temperature rises due to stirring, Tends to be difficult to maintain.

  Further, in the other electrostatic charge image developing toner according to the present embodiment, as described later, a colorant is further contained in the above configuration.

  Hereinafter, various materials constituting the toner of the exemplary embodiment will be described in detail.

-Binder resin-
First, in the toner of the present embodiment, a polyester resin is used as a binder resin, and if necessary, other binder resins other than the polyester resin (for example, styrene-acrylic resin) are used in combination. Also good. However, when other binder resins are used in combination, the proportion of the crystalline polyester resin in the total binder resin is 5% by mass or more and 20% by mass or less.

  As described above, the melting point Tm of the crystalline polyester resin is 25 ° C. or more and 50 ° C. or less, more preferably 25 ° C. or more and 40 ° C. or less. The melting point and glass transition temperature as the binder resin are preferably in the range of 45 ° C. or higher and 110 ° C. or lower, and more preferably in the range of 60 ° C. or higher and 90 ° C. or lower.

  The mixing ratio of the two types of binder resins can be selected in consideration of the relationship between the melting point of the crystalline polyester resin and the glass transition temperature of the amorphous resin. It is important to select a resin component that does not hinder the low-temperature fixability because the thermal melting characteristics of the component having a large content are generally dominant.

  This melting point can be determined as the melting peak temperature of input compensated differential scanning calorimetry based on JIS K-7121. The crystalline resin may show a plurality of melting peaks. In this case, the maximum peak is regarded as the melting point.

-Crystalline polyester resin-
The polyester resin is synthesized from a polyvalent carboxylic acid component and a polyhydric alcohol component. In the present invention, a commercially available product may be used as the polyester resin, or an appropriately synthesized product may be used. Below, the polyhydric carboxylic acid component and polyhydric alcohol component suitable for the synthesis | combination of crystalline polyester resin are demonstrated.

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

  Examples of the trivalent or higher carboxylic acid include 1,2,3-benzenetricarboxylic acid, 1,2,4-benzenetricarboxylic acid, 1,3,5-benzenetricarboxylic acid, and 11,2,4-naphthalenetricarboxylic acid. And their anhydrides and their lower alkyl esters. These may be used individually by 1 type and may use 2 or more types together.

  Further, it is more preferable to contain a dicarboxylic acid component having a double bond in addition to the above-mentioned aliphatic dicarboxylic acid and aromatic dicarboxylic acid. A dicarboxylic acid having a double bond can be suitably used to prevent hot offset at the time of fixing in that it can be radically cross-linked through the double bond. Examples of such dicarboxylic acids include, but are not limited to, maleic acid, fumaric acid, 3-hexenedioic acid, and 3-octenedioic acid. In addition, these lower esters, acid anhydrides and the like are also included. Among these, fumaric acid, maleic acid and the like are mentioned in terms of cost.

  As the polyhydric alcohol component, an aliphatic diol is preferable, and a linear aliphatic diol having a main chain portion having 7 to 20 carbon atoms is more preferable. When the aliphatic diol is branched, 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. Further, when the number of carbon atoms is less than 7, when the polycondensation with aromatic dicarboxylic acid is performed, the melting point becomes high and fixing at low temperature may be difficult. On the other hand, when the number exceeds 20, it is difficult to obtain practical materials. easy. The carbon number is more preferably 14 or less.

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

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

  Among the polyhydric alcohol components, the content of the aliphatic diol component is preferably 80 mol% or more, and more preferably 90% or more. When the content of the aliphatic diol component 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. is there.

  If necessary, monovalent acids such as acetic acid and benzoic acid, and monovalent alcohols such as cyclohexanol and benzyl alcohol can be used for the purpose of adjusting the acid value and the hydroxyl value.

  “Crystallinity” like a crystalline polyester resin means that in differential scanning calorimetry, it has a clear endothermic peak, not a stepwise change in endothermic amount. Specifically, the rate of temperature increase is 10 ° C. / It means that the half width of the endothermic peak when measured in minutes is within 6 ° C. On the other hand, a resin having a half-value width exceeding 6 ° C. or a resin in which no clear endothermic peak is observed means an amorphous resin, but a clear endothermic peak is recognized as an amorphous resin used in the present invention. It is preferable to use a resin that cannot be used.

  In addition to the polymer whose constituent component is a 100% polyester structure, the “crystalline polyester resin” as described above is a polymer (copolymer) obtained by polymerizing a component constituting polyester and another component together. ) Also means. However, in the latter case, the component other than the polyester constituting the polymer (copolymer) is 50% by mass or less.

-Amorphous resin-
Examples of the amorphous resin that can be used in the toner of the present embodiment include conventionally known thermoplastic binder resins, and specific examples include styrene, parachlorostyrene, α-methylstyrene, and the like. Styrene homopolymer or copolymer (styrene resin); methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, Homopolymers or copolymers of vinyl groups such as ethyl methacrylate, n-propyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate, etc .; vinyl nitriles such as acrylonitrile and methacrylonitrile Homopolymers or copolymers (vinyl resins); vinyl methyl ether Homopolymers or copolymers of vinyl ethers such as vinyl isobutyl ether (vinyl resins); Homopolymers or copolymers of vinyl ketones such as vinyl methyl ketone, vinyl ethyl ketone, vinyl isopropenyl ketone (vinyl type) Resins); Homopolymers or copolymers of olefins such as ethylene, propylene, butadiene, and isoprene (olefin resins); Non-vinyls such as epoxy resins, polyester resins, polyurethane resins, polyamide resins, cellulose resins, and polyether resins Examples include condensation resins and graft polymers of these non-vinyl condensation resins and vinyl monomers. These resins may be used alone or in combination of two or more. Among these resins, vinyl resins and polyester resins are particularly preferable.

  In the case of a vinyl resin, it is advantageous in that a resin particle dispersion can be easily prepared by emulsion polymerization or seed polymerization using an ionic surfactant or the like. Examples of the vinyl monomer include acrylic acid, methacrylic acid, maleic acid, cinnamic acid, fumaric acid, vinyl sulfonic acid, ethylene imine, vinyl pyridine, vinyl amine, and other vinyl polymer acids and vinyl polymer bases. The monomer used as a raw material is mentioned.

  On the other hand, when a polyester resin is used as the non-crystalline molecule in the toner of the present embodiment, the resin particle dispersion is obtained by emulsifying and dispersing the resin by adjusting the acid value of the resin or using an ionic surfactant. This is advantageous in that it can be easily prepared. The amorphous polyester resin used for emulsification dispersion is synthesized by dehydration condensation of a polyvalent carboxylic acid and a polyhydric alcohol.

  Examples of polycarboxylic acids include terephthalic acid, isophthalic acid, phthalic anhydride, trimellitic anhydride, pyromellitic acid, naphthalenedicarboxylic acid, and other aromatic carboxylic acids, maleic anhydride, fumaric acid, succinic acid, alkenyl Examples thereof include aliphatic carboxylic acids such as succinic anhydride and adipic acid, and alicyclic carboxylic acids such as cyclohexanedicarboxylic acid. These polyvalent carboxylic acids can be used alone or in combination. Of these polyvalent carboxylic acids, it is preferable to use aromatic carboxylic acids, and in order to take a crosslinked structure or a branched structure in order to ensure good fixability, tricarboxylic or higher carboxylic acids (trimerits) It is preferable to use an acid or an acid anhydride thereof in combination.

  Examples of polyhydric alcohols include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butanediol, hexanediol, neopentyl glycol, glycerin, and other aliphatic diols, cyclohexanediol, cyclohexanedimethanol, hydrogenated bisphenol A And aromatic diols such as bisphenol A ethylene oxide adduct and bisphenol A propylene oxide adduct. One or more of these polyhydric alcohols can be used. Among these polyhydric alcohols, aromatic diols and alicyclic diols are preferable, and among these, aromatic diols are more preferable. In order to secure good fixing properties, a trihydric or higher polyhydric alcohol (glycerin, trimethylolpropane, pentaerythritol) may be used in combination with the diol in order to take a crosslinked structure or a branched structure.

  In addition, monocarboxylic acid and / or monoalcohol is further added to the polyester resin obtained by polycondensation of polycarboxylic acid and polyhydric alcohol to esterify the hydroxyl group and / or carboxyl group at the polymerization terminal. The acid value of the polyester resin may be adjusted. Examples of the monocarboxylic acid include acetic acid, acetic anhydride, benzoic acid, trichloroacetic acid, trifluoroacetic acid, propionic anhydride and the like, and examples of the monoalcohol include methanol, ethanol, propanol, octanol, 2-ethylhexanol, and trifluoroethanol. , Trichloroethanol, hexafluoroisopropanol, phenol and the like.

  The polyester resin (that is, crystalline polyester resin or non-crystalline polyester resin) used in the present embodiment can be produced by subjecting the polyhydric alcohol and polyvalent carboxylic acid to a condensation reaction according to a conventional method. For example, the above polyhydric alcohol and polyvalent carboxylic acid, if necessary, a catalyst, and blended in a reaction vessel equipped with a thermometer, a stirrer, a flow-down condenser, and in the presence of an inert gas (such as nitrogen gas), Heat at 150 to 250 ° C to continuously remove by-product low-molecular compounds out of the reaction system, stop the reaction when it reaches the specified acid value, cool, and obtain the desired reactant Can be manufactured.

-Catalyst-
For the polycondensation of the carboxylic acid component and the alcohol component, it is preferable to use an esterification catalyst. Examples of the suitably used catalyst include organic metals such as dibutyltin dilaurate and dibutyltin oxide.

  The other catalyst is not particularly limited as long as it can promote the polycondensation reaction between the polyhydric alcohol and the polyvalent carboxylic acid, and all organic and inorganic catalysts can be used. For example, titanium alcoholates and metal alcoholates such as alkali and alkaline earth metal alkoxides can be used in combination.

  The amount of the catalyst is preferably 0.01% by mass or more and 1.0% by mass or less, and more preferably 0.1% by mass or more and 0.6% by mass or less with respect to 100% by mass of the total amount of the carboxylic acid component and the alcohol component. More preferred.

-Colorant-
The toner of the present embodiment usually contains a colorant except when used for special purposes such as a transparent toner.

  The colorant is not particularly limited as long as it is a known colorant. For example, carbon black such as furnace black, channel black, acetylene black, and thermal black, inorganic pigments such as bengara, bitumen, and titanium oxide, fast yellow, disazo Azo pigments such as yellow, pyrazolone red, chelate red, brilliant carmine, para brown, phthalocyanine pigments such as copper phthalocyanine, metal-free phthalocyanine, flavantron yellow, dibromoanthrone orange, perylene red, quinacridone red, dioxazine violet Examples thereof include cyclic pigments.

  Chrome Yellow, Hansa Yellow, Benzidine Yellow, Slen Yellow, Quinoline Yellow, Permanent Orange GTR, Pyrarozone Orange, Vulcan Orange, Watch Young Red, Permanent Red, Dupont Oil Red, Resol Red, Rhodamine B Lake, Lake Red C Rose Bengal, Aniline Blue, Ultramarine Blue, Calco Oil Blue, Methylene Blue Chloride, Phthalocyanine Blue, Phthalocyanine Green, Malachite Green Oxalate, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 122, C.I. I. Pigment 57: 1, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 17, C.I. I. Pigment blue 15: 1, C.I. I. Examples thereof include various pigments such as CI Pigment Blue 15: 3, and these can be used alone or in combination of two or more.

  It is also effective to use a colorant that has been surface-treated if necessary, or to use a pigment dispersant in combination. By appropriately selecting the type of the colorant, yellow toner, magenta toner, cyan toner, black toner, and the like can be obtained.

  The content of the colorant is preferably 1% by mass to 30% by mass, more preferably 1% by mass to 20% by mass, more preferably 1% by mass to 10% by mass with respect to 100% by mass of the binder resin. % Or less, more preferably 2% by mass or more and 10% by mass or less, and most preferably 2% by mass or more and 7% by mass or less. The colorant content is preferably as large as possible within a range that does not impair the smoothness of the image surface after fixing. When the content of the colorant is increased, the thickness of the image can be reduced when an image having the same density is obtained, which is advantageous in terms of prevention of offset.

-Release agent-
A release agent can be used in the toner of the present embodiment as necessary. The release agent is not particularly limited as long as it is a known release agent. For example, natural waxes such as carnauba wax, rice wax, and candelilla wax, low molecular weight polypropylene, low molecular weight polyethylene, sazole wax, and microcrystalline. Examples include, but are not limited to, synthesis of wax, Fischer-Tropsch wax, paraffin wax, montan wax and the like, and mineral-petroleum wax, ester wax such as fatty acid ester and montanic acid ester. Moreover, these mold release agents may be used individually by 1 type, and may be used together 2 or more types.

  The melting point of the release agent is preferably 60 ° C. or higher, more preferably 70 ° C. or higher, from the viewpoint of storage stability. Further, from the viewpoint of offset resistance at low temperatures, it is preferably 110 ° C. or lower, and more preferably 100 ° C. or lower. Furthermore, from the viewpoint of offset resistance at high temperatures, a release agent having a melting point of 100 ° C. or higher can be used in combination.

  The content of the release agent is preferably in the range of 1% by mass to 30% by mass and preferably in the range of 2% by mass to 20% by mass with respect to 100% by mass of the binder resin. More preferred. If the content of the release agent is less than 1 part by mass, the effect of adding the release agent becomes insufficient, which may cause hot offset at a high temperature. On the other hand, if the content exceeds 30% by mass, the mechanical strength of the toner is lowered, and therefore, the toner is easily destroyed by stress in the developing machine, which may cause carrier contamination.

-Other additives-
Various internal and external additives such as a charge control agent, inorganic powder (inorganic particles), and organic particles can be added to the toner according to the present embodiment as necessary.

-Internal additive-
The internal additive can be added mainly by a wet method, and examples thereof include metals such as ferrite, magnetite, reduced iron, cobalt, nickel, and manganese, alloys, or magnetic materials such as compounds containing these metals. .

  Examples of the charge control agent include quaternary ammonium salt compounds, nigrosine compounds, dyes composed of complexes of aluminum, iron, chromium, and triphenylmethane pigments. The inorganic powder is added mainly for the purpose of adjusting the viscoelasticity of the toner. For example, silica, alumina, titania, calcium carbonate, magnesium carbonate, calcium phosphate, cerium oxide, etc. Examples include all inorganic particles used as an external additive on the toner surface.

  The charge control agent is preferably made of a material that is difficult to dissolve in water in terms of controlling ionic strength that affects the stability of the aggregated particle forming process and the fusion process and reducing wastewater contamination.

-Dry external additive-
In the present embodiment, as described above, inorganic particles having an average particle diameter of 80 nm or more and 300 nm or less are used as the external additive added to the surface of the toner base particles by a dry method.

  Examples of inorganic particles include silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, silica sand, clay, mica, wollastonite, diatomaceous earth, cerium chloride, Examples include Bengala, chromium oxide, cerium oxide, antimony trioxide, magnesium oxide, zirconium oxide, silicon carbide, and silicon nitride. Among these, silica particles and titanium oxide particles are preferable, and hydrophobically treated particles are particularly preferable.

  Inorganic particles are generally used for the purpose of improving fluidity. The addition amount of the inorganic particles is preferably 0.01% by mass or more and 20% by mass or less with respect to 100% by mass of the toner.

-Various physical properties of toner-
The melting point of the toner is not particularly limited, but is preferably in the range of 45 ° C. or higher and 110 ° C. or lower, and more preferably in the range of 60 ° C. or higher and 90 ° C. or lower.

  If the melting point is less than 45 ° C., which corresponds to a lower limit temperature under a general high-temperature environment that is exposed when the toner is stored or after the image is formed, blocking may easily occur. This is because the toner suddenly drops in viscosity at the melting point and thus causes blocking when stored in a temperature environment higher than the melting point. On the other hand, when the melting point exceeds 110 ° C., low-temperature fixing may be difficult.

  As described above, the melting point is obtained as the melting peak temperature of the input compensated differential scanning calorimetry based on JIS K-7121.

  The volume average particle size of the toner in the exemplary embodiment is preferably 1 μm to 20 μm, more preferably 2 μm to 8 μm, and the number average particle size is preferably 1 μm to 20 μm, preferably 2 μm to 8 μm. More preferred. The measurement of the volume average particle diameter and the number average particle diameter will be described later.

-Toner production method-
The toner of the present embodiment is produced using, for example, an emulsion aggregation method. Here, when the toner is produced, a dispersion (resin particle dispersion or the like) in which each material constituting the toner is dispersed in an aqueous dispersion is prepared (emulsification step). Subsequently, a resin particle dispersion and other various dispersions (colorant dispersion, release agent dispersion, etc.) used as necessary are mixed to prepare a raw material dispersion.

  Next, toner base particles are obtained through an aggregated particle forming step for forming aggregated particles and a fusion step for fusing the aggregated particles in the raw material dispersion. In the case of producing a so-called core-shell structure type toner comprising a core layer and a shell layer covering the core layer, the resin particle dispersion is added to the raw material dispersion after the aggregated particle formation step. Then, a coating layer forming step is performed in which a resin layer is attached to the surface of the aggregated particles (which becomes a core layer when converted into a toner) to form a coating layer (which becomes a shell layer when converted into a toner), and then fused. Perform the process. In addition, although the resin component used for a coating layer formation process may be the same as that of the resin component which comprises a core layer, or different, Usually, an amorphous resin is used.

  Hereinafter, each step will be described in detail.

-Emulsification process-
In order to prepare a raw material dispersion for use in the aggregated particle forming step, in the emulsification step, an emulsified dispersion in which main materials constituting the toner are dispersed in an aqueous medium is prepared. Hereinafter, the resin particle dispersion, and other colorant dispersions, release agent dispersions, and the like used as necessary will be described.

-Resin particle dispersion-
The volume average particle size of the resin particles dispersed in the resin particle dispersion is preferably 0.01 μm or more and 1 μm or less, more preferably 0.03 μm or more and 0.8 μm or less, and further preferably 0.03 μm or more and 0 or less. .6 μm is preferred.

  If the volume average particle size of the resin particles exceeds 1 μm, the particle size distribution of the finally obtained toner may be widened, free particles may be generated, and performance and reliability may be easily reduced. . On the other hand, if the volume average particle size is in the above range, the above disadvantages are eliminated, compositional uneven distribution among toners is reduced, dispersion in the toner is improved, and variations in performance and reliability are advantageous. is there.

  In addition, the volume average particle diameter of the particle | grains contained in raw material dispersion liquid, such as a resin particle, can be measured with a laser diffraction type particle size distribution measuring apparatus (Horiba, LA-700).

  As a dispersion medium used for the resin particle dispersion and other dispersions, an aqueous medium is preferable. Examples of the aqueous medium include water such as distilled water and ion exchange water, and alcohols. These may be used individually by 1 type and may use 2 or more types together. In the present invention, it is preferable to add and mix a surfactant in the aqueous medium.

  Although it does not specifically limit as surfactant, For example, anionic surfactants, such as sulfate ester type, sulfonate type, phosphate ester type, soap type; amine salt type, quaternary ammonium salt type, etc. Nonionic surfactants such as polyethylene glycol-based, alkylphenol ethylene oxide adduct-based, polyhydric alcohol-based, and the like. Among these, anionic surfactants and cationic surfactants are preferable. The nonionic surfactant is preferably used in combination with the anionic surfactant or the cationic surfactant. The said surfactant may be used individually by 1 type, and may use 2 or more types together.

  Specific examples of the anionic surfactant include sodium dodecylbenzenesulfonate, sodium dodecylsulfate, sodium alkylnaphthalenesulfonate, sodium dialkylsulfosuccinate and the like. Specific examples of the cationic surfactant include alkylbenzene dimethyl ammonium chloride, alkyl trimethyl ammonium chloride, distearyl ammonium chloride and the like. Among these, ionic surfactants such as anionic surfactants and cationic surfactants are preferable.

  When the resin particle is a polyester resin, the aqueous medium has a self-water dispersibility containing a functional group that can be converted into an anion type by neutralization, and a part or all of the functional group that can be hydrophilic is neutralized with a base. A stable aqueous dispersion can be formed under the action of

  Since the functional group that can become a hydrophilic group by neutralization in the polyester resin is an acidic group such as a carboxyl group or a sulfone group, examples of the neutralizing agent include sodium hydroxide, potassium hydroxide, lithium hydroxide, and calcium hydroxide. And inorganic bases such as sodium carbonate and ammonia, and organic bases such as diethylamine, triethylamine and isopropylamine.

  On the other hand, when adjusting a resin particle dispersion using a polyester resin, a phase inversion emulsification method is used. The phase inversion emulsification method may also be used when adjusting the resin particle dispersion using a binder resin other than the polyester resin. In the phase inversion emulsification method, a resin to be dispersed is dissolved in a hydrophobic organic solvent in which the resin is soluble, a base is added to the organic continuous phase (O phase), and the aqueous medium (W In this method, the resin is converted from W / O to O / W (so-called phase inversion) to form a discontinuous phase, and the resin is dispersed and stabilized in the form of particles in an aqueous medium. is there.

  Examples of the organic solvent used for this phase inversion emulsification include ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, tert-butanol, n-amyl alcohol, isoamyl alcohol, sec-amyl alcohol, and tert. -Alcohols such as amyl alcohol, 1-ethyl-1-propanol, 2-methyl-1-butanol, n-hexanol, cyclohexanol, ketones such as methyl ethyl ketone, methyl isobutyl ketone, ethyl butyl ketone, cyclohexanone, isophorone, tetrahydrofuran , Ethers such as dimethyl ether, diethyl ether, dioxane, methyl acetate, ethyl acetate, acetic acid-n-propyl, isopropyl acetate, acetic acid-n-butyl, isobutyl acetate, vinegar -Sec-butyl, acetate-3-methoxybutyl, methyl propionate, ethyl propionate, butyl propionate, dimethyl oxalate, diethyl oxalate, dimethyl succinate, diethyl succinate, diethyl carbonate, dimethyl carbonate, Ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol ethyl ether acetate, diethylene glycol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether , Diethylene glycol ethyl ether acetate Glycol derivatives such as propylene glycol, propylene glycol monomethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, propylene glycol methyl ether acetate, dipropylene glycol monobutyl ether, 3-methoxy-3-methylbutanol, 3-methoxy Examples include butanol, acetonitrile, dimethylformamide, dimethylacetamide, diacetone alcohol, ethyl acetoacetate and the like. These solvents can be used singly or in combination of two or more.

  The amount of the organic solvent used for phase inversion emulsification is difficult to determine in general because the amount of solvent for obtaining a desired dispersed particle size varies depending on the physical properties of the resin. However, in the present invention, since the content of the tin compound catalyst in the resin is larger than that of a normal polyester resin, it is preferable that the amount of solvent relative to the resin mass is relatively large. When the amount of the solvent is small, the emulsifiability becomes insufficient, and the particle size of the resin particles may be increased or the particle size distribution may be broadened.

  When the binder resin is dispersed in water, it is preferable to neutralize part or all of the carboxyl groups in the resin with a neutralizing agent as necessary. Examples of the neutralizing agent include inorganic alkalis such as potassium hydroxide and sodium hydroxide, ammonia, monomethylamine, dimethylamine, triethylamine, monoethylamine, diethylamine, triethylamine, mono-npropylamine, dimethyl n-propylamine, monoethanol. Amines such as amine, diethanolamine, triethanolamine, N-methylethanolamine, N-aminoethylethanolamine, N-methyldiethanolamine, monoisopropanolamine, diisopropanolamine, triisopropanolamine, N, N-dimethylpropanolamine, etc. 1 type or 2 types or more selected from these can be used. By adding these neutralizing agents, the pH during emulsification can be adjusted to near neutrality, and hydrolysis of the resulting polyester resin dispersion can be prevented.

  Also during the phase inversion emulsification, a dispersant may be added for the purpose of stabilizing the dispersed particles and preventing the thickening of the aqueous medium. Examples of the dispersant include water-soluble polymers such as polyvinyl alcohol, methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, sodium polyacrylate, and sodium polymethacrylate, sodium dodecylbenzenesulfonate, sodium octadecylsulfate, and oleic acid. Anionic surfactants such as sodium, sodium laurate, potassium stearate, cationic surfactants such as laurylamine acetate, stearylamine acetate, lauryltrimethylammonium chloride, zwitterionic surfactants such as lauryldimethylamine oxide, Polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene alkyl amine, etc. Surfactants such as on-surfactant, tricalcium phosphate, aluminum hydroxide, calcium sulfate, calcium carbonate, and inorganic compounds such as barium carbonate. These dispersants may be used alone or in combination of two or more. The dispersant is preferably added in an amount of 0.01% by mass to 20% by mass with respect to 100% by mass of the binder resin.

  The emulsification temperature at the time of phase inversion emulsification is preferably below the boiling point of the organic solvent and above the melting point or glass transition point of the binder resin. When the emulsification temperature is lower than the melting point or glass transition point of the binder resin, it is difficult to adjust the resin particle dispersion. In addition, when emulsifying above the boiling point of the organic solvent, the emulsification may be performed with a pressure-sealed device.

  The content of the resin particles contained in the resin particle dispersion is usually preferably 5% by mass or more and 50% by mass or less, and more preferably 10% by mass or more and 40% by mass or less. When the content is out of the above range, the particle size distribution of the resin particles is widened, and the characteristics may be deteriorated.

-Colorant dispersion-
As a method of dispersing the colorant when adjusting the colorant dispersion, any 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. There are no restrictions. If necessary, an aqueous dispersion of these colorants can be prepared using a surfactant, or an organic solvent dispersion of these colorants can be prepared using a dispersant. As the surfactant and the dispersing agent used for dispersion, the same dispersing agents that can be used when dispersing the binder resin can be used.

In preparing the raw material dispersion, the colorant dispersion may be mixed at the same time with the dispersion in which other particles are dispersed, or may be divided and added and mixed in multiple stages.

  The content of the colorant particles contained in the colorant dispersion is usually preferably 5% by mass or more and 50% by mass or less, and more preferably 10% by mass or more and 40% by mass or less. When the content is out of the above range, the particle size distribution of the colorant particles is widened, and the characteristics may be deteriorated.

-Release agent dispersion-
As in the case of emulsifying and dispersing a binder resin other than a polyester resin, the release agent dispersion is dispersed in water together with an ionic surfactant and heated to a temperature equal to or higher than the melting point of the release agent. It can be adjusted by applying a strong shearing force using a pressure discharge type disperser. Thereby, the release agent particles having a volume average particle diameter of 1 μm or less can be dispersed. As the dispersion medium in the release agent dispersion, the same dispersion medium as used for the binder resin can be used.

  In addition, as a device for mixing and dispersing the binder resin, the colorant and the like with a dispersion medium, a known device can be used, for example, a homomixer (Special Machine Industries Co., Ltd.) or a slasher (Mitsui Mining Co., Ltd.). ), Cavitron (Eurotech Co., Ltd.), Microfluidizer (Mizuho Kogyo Co., Ltd.), Menton Gorin homogenizer (Gorin Co., Ltd.), Nanomizer (Nanomizer Co., Ltd.), Static Mixer (Noritake Company), etc. A machine can be used.

  Depending on the purpose, other components such as a release agent, an internal additive, a charge control agent, and an inorganic powder as described above may be dispersed in the binder resin dispersion.

  In addition, when preparing a dispersion of other components other than the binder resin, the colorant, and the release agent, the volume average particle diameter of the particles dispersed in the dispersion is usually preferably 1 μm or less, More preferably, it is 0.01 μm or more and 0.5 μm or less. When the volume average particle diameter exceeds 1 μm, the particle diameter distribution of the finally obtained toner may be broadened, free particles may be generated, and performance and reliability may be easily lowered. On the other hand, when the volume average particle size is in the above range, there are no disadvantages, and the uneven distribution among the toners is reduced, the dispersion in the toner is good, and the variation in performance and reliability is reduced.

-Aggregated particle formation process-
In the agglomerated particle forming step, in addition to the resin particle dispersion, a colorant dispersion is usually added, and other dispersion added as necessary (for example, a release agent dispersion in which a release agent is dispersed) Etc.) is further added to the raw material dispersion obtained by mixing, and heated to form aggregated particles in which these particles are aggregated. In the case where the resin particles are a crystalline resin such as crystalline polyester, the aggregated particles obtained by aggregating these particles by heating at a temperature near the melting point of the crystalline resin and at a temperature not higher than the melting point are used. Form.

  Aggregated particles are formed by adding a flocculant at room temperature under stirring with a rotary shearing homogenizer to make the pH of the raw material dispersion acidic. In order to suppress rapid aggregation due to heating, it is preferable to adjust the pH at the stage of stirring and mixing at room temperature and add a dispersion stabilizer as necessary.

  As the aggregating agent used in the agglomerated particle forming step, a surfactant having a polarity opposite to that of the surfactant used as the dispersing agent to be added to the raw material dispersion, that is, an inorganic metal salt or a divalent or higher valent metal complex is preferably used. be able to. 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.

  Moreover, the additive which forms a complex or a similar bond with the metal ion of a flocculant can be used as needed. As this additive, a chelating agent is preferably used.

  Here, 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. And 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.

  Moreover, as a chelating agent, it is preferable to use a water-soluble chelating agent. The non-water-soluble chelating agent has poor dispersibility in the raw material dispersion, and may not sufficiently capture metal ions due to the aggregating agent in the toner.

  The chelating agent is not particularly limited as long as it is a known water-soluble chelating agent. For example, oxycarboxylic acids such as tartaric acid, citric acid and gluconic acid, iminodiacid (IDA), nitrilotriacetic acid (NTA), ethylenediaminetetraacetic acid ( EDTA) and the like can be preferably used.

  The addition amount of the chelating agent is preferably within a range of 0.01% by mass or more and 5.0% by mass or less with respect to 100% by mass of the binder resin, and is 0.1% by mass or more and less than 3.0% by mass. It is more preferable that If the addition amount of the chelating agent is less than 0.01% by mass, the effect of adding the chelating agent may not be exhibited. On the other hand, if it exceeds 5.0% by mass, the chargeability is adversely affected, and the viscoelasticity of the toner changes dramatically, which may adversely affect low-temperature fixability and image glossiness.

  The chelating agent is added during or before and after the aggregated particle forming step and the coating layer forming step, but the temperature of the raw material dispersion is not required for the addition, and it may be added at room temperature. Either may be added after adjusting to the temperature in the tank in the aggregated particle forming step or the coating layer forming step.

-Coating layer formation process-
After the aggregated particle forming step, the coating layer forming step is performed. In the coating layer forming step, the coating layer is formed by attaching resin particles for forming a coating layer to the surface of the aggregated particles formed through the above-described aggregated particle forming step. Thereby, a toner having a so-called core-shell structure can be obtained.

  The coating layer can be formed by usually adding a resin particle dispersion containing non-crystalline resin particles to the raw material dispersion in which the aggregated particles (core particles) are formed in the aggregated particle forming step.

  In addition, after finishing a coating layer formation process, although a fusion process is implemented, a coating layer can also be divided and formed in multiple steps by repeatedly implementing a coating layer formation process and a fusion process. .

-Fusion process-
In the coalescence step performed after the aggregated particle forming step or the aggregated particle forming step and the coating layer forming step, the pH of the suspension containing the aggregated particles formed through these steps is set to 6.5 to 8. By setting the range to about 5, the progress of aggregation is stopped. Then, after the progress of aggregation is stopped, the aggregated particles are fused by heating. When a crystalline resin is used as the binder resin, the aggregated particles are fused by heating at a temperature equal to or higher than the melting point of the binder resin.

-Cleaning, drying process, etc.-
After completing the coalesced particle fusion step, desired toner particles are obtained through an arbitrary washing step, solid-liquid separation step, and drying step. In the washing step, the toner base particles are formed with an aqueous solution of a strong acid such as hydrochloric acid, sulfuric acid, or nitric acid. After removing the adhering dispersant, it is desirable to thoroughly wash with ion exchange water or the like until the filtrate becomes neutral. Moreover, although there is no restriction | limiting in particular in a solid-liquid separation process, From the point of productivity, suction filtration, pressure filtration, etc. are suitable. Further, the drying process is not particularly limited, but freeze drying, flash jet drying, fluidized drying, vibration fluidized drying and the like are preferably used from the viewpoint of productivity. 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. At this time, the moisture content after drying of the toner base particles is preferably adjusted to 1.0% by mass or less, and more preferably adjusted to 0.5% by mass or less.

  In addition, various external additives as described above are added to the toner base particles after drying as necessary.

<Developer for developing electrostatic image>
The developer for developing an electrostatic charge image (hereinafter referred to as “developer”) of the present embodiment is not particularly limited as long as it contains the toner of the present embodiment described above. One-component developer or two-component development Any of the agents may be used. When used as a two-component developer, a toner and a carrier can be mixed and used.

  There is no restriction | limiting in particular as a carrier which can be used for a two-component developer, A well-known carrier can be used. Examples thereof include magnetic metals such as iron oxide, nickel and cobalt, magnetic oxides such as ferrite and magnetite, resin-coated carriers having a resin coating layer on the surface of the core material, and magnetic dispersion carriers. Further, a resin dispersion type carrier in which a conductive material or the like is dispersed in a matrix resin may be used.

  Coating resins and matrix resins used for carriers include polyethylene, polypropylene, polystyrene, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl ether, polyvinyl ketone, vinyl chloride-vinyl acetate copolymer, styrene-acrylic. Examples thereof include, but are not limited to, acid copolymers, straight silicone resins composed of organosiloxane bonds or modified products thereof, fluororesins, polyesters, polycarbonates, phenol resins, epoxy resins and the like.

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

  Examples of the core material of the carrier include magnetic metals such as iron, nickel, and cobalt, magnetic oxides such as ferrite and magnetite, and glass beads. However, in order to use the carrier for the magnetic brush method, it is a magnetic material. It is preferable.

  The volume average particle size of the core material of the carrier is generally from 10 μm to 500 μm, and preferably from 30 μm to 100 μm.

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

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

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

<Image forming apparatus>
Next, an example of the image forming apparatus according to the present embodiment will be described.

  FIG. 1 is a schematic diagram illustrating a configuration example of an image forming apparatus for forming an image by the image forming method of the present embodiment. In the illustrated image forming apparatus 200, four electrophotographic photosensitive members 401 a to 401 d are disposed in parallel in the housing 400 along the intermediate transfer belt 409. The electrophotographic photoreceptors 401a to 401d form, for example, images in which the electrophotographic photoreceptor 401a is yellow, the electrophotographic photoreceptor 401b is magenta, the electrophotographic photoreceptor 401c is cyan, and the electrophotographic photoreceptor 401d is black. Is possible.

  Each of the electrophotographic photosensitive members 401a to 401d can be rotated in a predetermined direction (counterclockwise on the paper surface), and the charging rolls 402a to 402d, the developing devices 404a to 404d, and the primary transfer roll 410a along the rotation direction. To 410d and cleaning blades 415a to 415d are arranged. Each of the developing devices 404a to 404d can be supplied with toner of four colors of black, yellow, magenta and cyan accommodated in the toner cartridges 405a to 405d, and the primary transfer rolls 410a to 410d are respectively intermediate transfer belts. 409 is in contact with the electrophotographic photoreceptors 401a to 401d.

  Further, an exposure device 403 is disposed at a predetermined position in the housing 400, and it becomes possible to irradiate the surfaces of the charged electrophotographic photoreceptors 401a to 401d with a light beam emitted from the exposure device 403. ing. Accordingly, charging, exposure, development, primary transfer, and cleaning are sequentially performed in the rotation process of the electrophotographic photosensitive members 401a to 401d, and the toner images of the respective colors are transferred onto the intermediate transfer belt 409 in an overlapping manner.

  Here, the charging rolls 402a to 402d contact the surface of the electrophotographic photoreceptors 401a to 401d with a conductive member (charging roll), and apply a voltage uniformly to the photoreceptor to charge the photoreceptor surface to a predetermined potential. (Charging process). In addition to the charging roll shown in this embodiment, charging by a contact charging method may be performed using a charging brush, a charging film, a charging tube, or the like. Moreover, you may charge by the non-contact system using a corotron or a scorotron.

  As the exposure apparatus 403, an optical system apparatus or the like that can expose a light source such as a semiconductor laser, an LED (light emitting diode), a liquid crystal shutter, or the like on the surfaces of the electrophotographic photosensitive members 401a to 401d can be used. Among these, when an exposure apparatus capable of exposing non-interference light is used, interference fringes between the electroconductive substrates of the electrophotographic photoreceptors 401a to 401d and the photosensitive layer can be prevented.

  As the developing devices 404a to 404d, a general developing device that develops the two-component electrostatic image developer in contact or non-contact with the developer can be used (developing step). Such a developing device is not particularly limited as long as a two-component electrostatic image developing developer is used, and a known one can be appropriately selected according to the purpose. In the primary transfer process, a primary transfer bias having a polarity opposite to that of the toner carried on the image carrier is applied to the primary transfer rolls 410a to 410d, so that each color toner is transferred from the image carrier to the intermediate transfer belt 409. The primary transfer is performed sequentially.

  The cleaning blades 415a to 415d are for removing residual toner adhering to the surface of the electrophotographic photosensitive member after the transfer process, and the electrophotographic photosensitive member cleaned by this cleaning process is repeatedly used in the above-described image forming process. Is done. Examples of the material for the cleaning blade include urethane rubber, neoprene rubber, and silicone rubber.

  The intermediate transfer belt 409 is supported with a predetermined tension by a drive roll 406, a backup roll 408, and a tension roll 407, and can rotate without causing deflection due to the rotation of these rolls. Further, the secondary transfer roll 413 is disposed so as to contact the backup roll 408 via the intermediate transfer belt 409.

  By applying a secondary transfer bias having a reverse polarity to the toner on the intermediate transfer member to the secondary transfer roll 413, the toner is secondarily transferred from the intermediate transfer belt to the recording medium. The intermediate transfer belt 409 that has passed between the backup roll 408 and the secondary transfer roll 413 is cleaned by, for example, a cleaning blade 416 disposed near the drive roll 406 or a static eliminator (not shown). It is repeatedly used for the next image forming process. A tray (transfer medium tray) 411 is provided at a predetermined position in the housing 400, and the transfer medium 500 such as paper in the tray 411 is transferred to the intermediate transfer belt 409 and the secondary transfer roll by the transfer roll 412. Then, the paper is sequentially transferred between the two fixing rolls 414 that are in contact with each other and the two fixing rolls 414, and then discharged to the outside of the housing 400.

<Image forming method>
The image forming method according to the present embodiment includes at least the step of charging the image carrier, the step of forming a latent image on the image carrier, and the latent image on the latent image carrier for developing the electrostatic image described above. A step of developing using a developer, a primary transfer step of transferring the developed toner image onto the intermediate transfer member, and a secondary transfer step of transferring the toner image transferred to the intermediate transfer member to a recording medium And a step of fixing the toner image by heat and pressure. The developer is a developer containing at least the electrostatic latent image developing toner of the present invention. The developer may be either a one-component system or a two-component system.

  As each of the above steps, a known step in the image forming method can be used.

  As the latent image holding member, for example, an electrophotographic photosensitive member and a dielectric recording member can be used. In the case of an electrophotographic photosensitive member, the surface of the electrophotographic photosensitive member is uniformly charged by a corotron charger, a contact charger or the like and then exposed to form an electrostatic latent image (latent image forming step). Next, the toner particles are adhered to the electrostatic latent image in contact with or in proximity to a developing roll having a developer layer formed on the surface, thereby forming a toner image on the electrophotographic photosensitive member (developing step). The formed toner image is transferred onto the surface of a transfer medium such as paper using a corotron charger or the like (transfer process). Further, if necessary, the toner image transferred to the surface of the transfer material is heat-fixed by a fixing device to form a final toner image.

  In the heat fixing by the fixing machine, a release agent is usually supplied to a fixing member in the fixing machine in order to prevent an offset or the like.

  The method for supplying the release agent to the surface of the roller or belt, which is a fixing member used for heat fixing, is not particularly limited. For example, a pad method using a pad impregnated with a liquid release agent, a web method, a roller method. Non-contact shower method (spray method) and the like, and the web method and the roller method are particularly preferable. These methods are advantageous in that the release agent can be supplied uniformly and it is easy to control the supply amount. In order to supply the release agent uniformly to the entire fixing member by the shower method, it is necessary to use a separate blade or the like.

  Examples of the transfer target (recording material) to which the toner image is transferred include plain paper, OHP sheet, and the like used in electrophotographic copying machines and printers.

[Appendix]
(1) A toner for developing an electrostatic charge image, wherein the toner shape SF1 to which inorganic particles having an average particle diameter of 80 nm to 300 nm are externally added is 110 to 140.

  Hereinafter, the present invention will be described by way of examples, but the present invention is not limited thereto. In the examples, unless otherwise specified, “part” represents “part by mass” and “%” represents “% by mass”.

<Measuring method of various characteristics>
First, methods for measuring physical properties of toners and the like used in Examples and Comparative Examples will be described.

(Toner particle size and particle size distribution measurement method)
In the present invention, the toner particle size and particle size distribution were measured using Multisizer II (Beckman-Coulter) as the measuring device and ISOTON-II (Beckman-Coulter) as the electrolyte.

  As a measurement method, 0.5 to 50 mg of a measurement sample is added to 2 ml of a 5% aqueous solution of a surfactant, preferably sodium alkylbenzenesulfonate, as a dispersant. This was added to 100 to 150 ml of the electrolytic solution. The electrolytic solution in which the sample is suspended is subjected to a dispersion treatment with an ultrasonic disperser for about 1 minute, and the particle size distribution of particles having a diameter of 2 to 60 μm is measured using the Multisizer II type with an aperture diameter of 100 μm. The average particle size was determined. The number of particles to be measured was 50,000.

  The particle size distribution of the toner was determined by the following method. For the particle size range (channel) obtained by dividing the measured particle size distribution, draw the volume cumulative distribution from the smaller particle size, define the cumulative volume particle size to be 16% cumulative as D16v, and the cumulative volume to be 50% cumulative The particle size is defined as D50v. Further, the cumulative volume particle size that is 84% cumulative is defined as D84v.

The volume average particle size in the present invention is D50v, and the volume average particle size index GSDv is calculated by the following equation.
Formula: GSDv = {(D84v) / (D16v)} ^0.5

  Moreover, when the particle diameter to measure was less than 2 micrometers, it measured using the laser diffraction type particle size distribution measuring apparatus (LA-700: made by Horiba, Ltd.). As a measurement method, a sample in a dispersion is adjusted to have a solid content of about 2 g, and ion exchange water is added thereto to make about 40 ml. This is put into the cell until an appropriate concentration is reached, waits for about 2 minutes, and is measured when the concentration in the cell becomes almost stable. The obtained volume average particle diameter for each channel was accumulated from the smaller volume average particle diameter, and the volume average particle diameter was determined to be 50%.

  When measuring powders such as external additives, 2 g of a measurement sample is added to 50 ml of a 5% aqueous solution of a surfactant, preferably sodium alkylbenzenesulfonate, and 2 with an ultrasonic disperser (1,000 Hz). A sample was prepared by dispersing for a minute, and the measurement was performed in the same manner as the above dispersion.

(Measurement method of weight average molecular weight and molecular weight distribution of resin)
In the present invention, the molecular weight of the binder resin or the like is determined under the following conditions. GPC uses “HLC-8120GPC, SC-8020 (manufactured by Tosoh Corporation)”, and the column uses two “TSKgel, SuperHM-H (6.0 mm ID × 15 cm, manufactured by Tosoh Corporation)” THF (tetrahydrofuran) was used as an eluent. As experimental conditions, an experiment was performed using a sample concentration of 0.5%, a flow rate of 0.6 ml / min, a sample injection amount of 10 μl, a measurement temperature of 40 ° C., and an IR detector. The calibration curve is “polystylen standard sample TSK standard” manufactured by Tosoh Corporation: “A-500”, “F-1”, “F-10”, “F-80”, “F-380”, “A-2500”. ”,“ F-4 ”,“ F-40 ”,“ F-128 ”, and“ F-700 ”.

(Measuring method of glass transition temperature, melting point and endothermic peak temperature of resin)
The endothermic peak temperature of the crystalline polyester resin and the glass transition temperature (Tg) of the amorphous polyester resin can be obtained using a differential scanning calorimeter (manufactured by Shimadzu Corporation: DSC-60A) in accordance with ASTM D3418. . The temperature correction of the detection part of this apparatus (DSC-60A) uses the melting point of indium and zinc, and the correction of heat quantity uses the heat of fusion of indium. For the sample, an aluminum pan was used, an empty pan was set for control, the temperature was raised at a rate of temperature increase of 10 ° C./min, held at 200 ° C. for 5 minutes, and liquid nitrogen was used from 200 ° C. to 0 ° C. The temperature is lowered at 10 ° C./minute, held at 0 ° C. for 5 minutes, and then heated again from 0 ° C. to 200 ° C. at 10 ° C./minute. The analysis is performed from the endothermic curve at the second temperature rise, and the onset temperature is set to Tg for the amorphous polyester resin, and the endothermic peak temperature and the melting point Tm from the maximum peak for the crystalline polyester resin.

(Toner shape factor SF1 measurement method)
The shape factor SF1 of the toner is a shape factor SF indicating the degree of unevenness on the toner particle surface, and was calculated by the following equation.
Formula: SF1 = (ML ² / A) × (π / 4) × 100
In the formula, ML represents the maximum length of toner particles, and A represents the projected area of the particles. For the measurement of the shape factor SF1, first, an optical microscope image of toner dispersed on a slide glass was taken into an image analysis device through a video camera, and SF was calculated for 50 or more toners to obtain an average value.

[Preparation of resin particle dispersion, release agent dispersion, and colorant dispersion]
<Preparation of crystalline polyester resin dispersion A>
1,3-propanediol 51 mol%, suberic acid 49 mol%, dibutyltin oxide 0.08 mol% as a catalyst were mixed in the flask, heated to 220 ° C. under reduced pressure, and subjected to a dehydration condensation reaction for 6.5 hours. Thus, a crystalline polyester resin was obtained. Next, 80 parts by mass of this crystalline polyester resin and 720 parts by mass of deionized water were placed in a stainless beaker, placed in a warm bath, and heated to 60 ° C. When the crystalline polyester resin melted, the mixture was stirred at 7000 rpm using a homogenizer (manufactured by IKA: Ultra Tarrax T50). Then, while adding 1.8 parts by mass of an anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen RK; 20% by mass), emulsification and dispersion are carried out to disperse a crystalline polyester resin having a volume average particle size of 0.160 μm. Liquid A (solid content 10% by mass) was obtained. The obtained crystalline polyester resin A had a melting point Tm (endothermic peak temperature) of 47 ° C.

<Preparation of crystalline polyester resin dispersion B>
Crystalline polyester is prepared by mixing in a flask at a ratio of 52 mol% pentanediol, 48 mol% succinic acid and 0.08 mol% dibutyltin oxide as a catalyst, heating to 220 ° C. in a reduced-pressure atmosphere, and conducting a dehydration condensation reaction for 6 hours. A resin was obtained. Next, 80 parts by mass of this crystalline polyester resin and 720 parts by mass of deionized water were placed in a stainless beaker, placed in a warm bath, and heated to 55 ° C. When the crystalline polyester resin melted, the mixture was stirred at 7000 rpm using a homogenizer (manufactured by IKA: Ultra Tarrax T50). Then, while adding 1.8 parts by mass of an anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen RK; 20% by mass), emulsification and dispersion are carried out to disperse a crystalline polyester resin having a volume average particle size of 0.160 μm. A liquid B (solid content: 10% by mass) was obtained. The obtained crystalline polyester resin B had a melting point Tm of 32 ° C.

<Preparation of crystalline polyester resin dispersion C>
1,6-hexanediol 51 mol%, pimelic acid 49 mol%, dibutyltin oxide 0.08 mol% as a catalyst are mixed in the flask, heated to 220 ° C. under reduced pressure, and subjected to a dehydration condensation reaction for 6.5 hours. Thus, a crystalline polyester resin was obtained. Next, 80 parts by mass of this crystalline polyester resin and 720 parts by mass of deionized water were placed in a stainless beaker, placed in a warm bath, and heated to 55 ° C. When the crystalline polyester resin melted, the mixture was stirred at 7000 rpm using a homogenizer (manufactured by IKA: Ultra Tarrax T50). Then, while adding 1.8 parts by mass of an anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen RK; 20% by mass), emulsification and dispersion are carried out to disperse a crystalline polyester resin having a volume average particle size of 0.160 μm. Liquid C (solid content 10% by mass) was obtained. The obtained crystalline polyester resin C had a melting point Tm of 52 ° C.

<Preparation of crystalline polyester resin dispersion D>
By mixing in a flask at a ratio of 52 mol% of pentanediol, 48 mol% of glutaric acid and 0.08 mol% of dibutyltin oxide as a catalyst, the mixture is heated to 200 ° C. in a reduced-pressure atmosphere, and subjected to a dehydration condensation reaction for 4 hours. A polyester resin was obtained. Next, 80 parts of this crystalline polyester resin and 720 parts of deionized water were placed in a stainless steel beaker, heated to 55 ° C. in a warm bath, and when the crystalline polyester resin melted, a homogenizer (manufactured by IKA: Ultra Turrax) The mixture was stirred at 7000 rpm using T50). Next, the emulsion was dispersed while adding 1.8 parts of an anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen RK; 20% by mass) dropwise to obtain a crystalline resin dispersion D having an average particle size of 0.165 μm ( 10 mass% solid content) was obtained. The endothermic peak temperature of the obtained crystalline polyester resin D was 22 ° C.

<Preparation of crystalline polyester resin dispersion G>
Pentanediol 45 mol%, 1,6-hexanediol 7 mol%, glutaric acid 48 mol%, dibutyltin oxide 0.08 mol% as a catalyst were mixed in the flask, heated to 210 ° C under reduced pressure, and heated for 4 hours. A crystalline polyester resin was obtained by performing a dehydration condensation reaction. Next, 80 parts of this crystalline polyester resin and 720 parts of deionized water were placed in a stainless steel beaker, heated to 55 ° C. in a warm bath, and when the crystalline polyester resin melted, a homogenizer (manufactured by IKA: Ultra Turrax) The mixture was stirred at 7000 rpm using T50). Next, the emulsion was dispersed while 1.8 parts of an anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen RK; 20% by mass) was added dropwise to obtain a crystalline resin dispersion F having an average particle size of 0.170 μm ( 10 mass% solid content) was obtained. The endothermic peak temperature of the obtained crystalline polyester resin G was 27 ° C.

<Preparation of crystalline polyester resin dispersion H>
Pentanediol 40mol%, 1,6-hexanediol 12mol%, succinic acid 48mol%, dibutyltin oxide 0.08mol% as a catalyst were mixed in the flask, heated to 220 ° C under reduced pressure, and dehydrated for 6 hours. By conducting the reaction, a crystalline polyester resin was obtained. Next, 80 parts by mass of this crystalline polyester resin and 720 parts by mass of deionized water were placed in a stainless beaker, placed in a warm bath, and heated to 60 ° C. When the crystalline polyester resin melted, the mixture was stirred at 7000 rpm using a homogenizer (manufactured by IKA: Ultra Tarrax T50). Then, while adding 1.8 parts by mass of an anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen RK; 20% by mass), emulsification and dispersion are carried out to disperse a crystalline polyester resin having a volume average particle size of 0.160 μm. A liquid G (solid content: 10% by mass) was obtained. The crystalline polyester resin H obtained had an endothermic peak temperature of 47 ° C.

<Preparation of amorphous polyester resin dispersion E>
Addition of dimethyl terephthalate 23 mol%, isophthalic acid 10 mol%, dodecenyl succinic anhydride 15 mol%, trimellitic anhydride 3 mol%, bisphenol A ethylene oxide in a reaction vessel equipped with a stirrer, thermometer, condenser and nitrogen gas inlet tube 5 mol% of the product and 45 mol% of the bisphenol A propylene oxide adduct were added, and after replacing the inside of the reaction vessel with dry nitrogen gas, the catalyst was added at a rate of 0.06 mol% of dibutyltin oxide and about 190 ° C. under a nitrogen gas stream. For about 7 hours, and after raising the temperature to about 250 ° C. for about 5.0 hours, the reaction vessel is depressurized to 10.0 mmHg and stirred for about 0.5 hours under reduced pressure. Thus, an amorphous polyester resin E was obtained. The obtained amorphous polyester resin E had a glass transition point (Tg) of 55 ° C. The weight average molecular weight (Mw) was 21,200.

<Preparation of amorphous polyester resin dispersion F>
Into a reaction vessel equipped with a stirrer, thermometer, condenser, and nitrogen gas introduction tube, 15 mol% of bisphenol A ethylene oxide adduct, 35 mol% of bisphenol A propylene oxide adduct, and 50 mol% of terephthalic acid were charged and put in the reaction vessel. Was replaced with dry nitrogen gas, 1.0% by mass of dibutyltin oxide was added, and the mixture was allowed to stir and react at about 190 ° C. for about 7 hours under a nitrogen gas stream. The temperature was raised to 240 ° C. over time, and the dehydration condensation reaction was continued at 240 ° C. for another 2.5 hours. Amorphous polyester resin having a glass transition point of 63 ° C. and a weight average molecular weight (Mw) of 17000 (A )

-Preparation of release agent dispersion (1)-
Ester wax WEP-5 (Nippon Yushi Co., Ltd.): 50 parts Anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen RK): 5 parts Ion-exchanged water: 200 parts , Dispersed using a homogenizer (manufactured by IKA: Ultra Tarrax T50), and then dispersed with a Menton Gorin high-pressure homogenizer (Gorin) to release a release agent having an average particle size of 0.21 μm. A mold dispersion (1) (release agent concentration: 26% by mass) was prepared.

-Preparation of colorant dispersion (1)-
Cyan pigment (Pigment Blue 15: 3 (copper phthalocyanine) manufactured by Dainichi Seika Co., Ltd.): 100 parts Anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen R): 15 parts Ion-exchanged water: 900 parts A colorant dispersion (1) obtained by mixing, dissolving, and dispersing a colorant (cyan pigment) by dispersing for about 1 hour using a high-pressure impact disperser Ultimateizer (manufactured by Sugino Machine Co., Ltd., HJP30006) Was prepared. The average particle diameter of the colorant (cyan pigment) in the colorant dispersion was 0.13 μm, and the colorant particle concentration was 25% by mass.

-Preparation of colorant dispersion (2)-
Magenta pigment (CI Pigment Red 122) 70 parts Nonionic surfactant (Nonipol 400: manufactured by Sanyo Chemical Co., Ltd.) 5 parts Ion-exchanged water 200 parts The above ingredients are mixed to obtain a colorant dispersion (1 ) To prepare a colorant dispersant (2).

-Preparation of colorant dispersion (3)-
Yellow pigment (CI Pigment Yellow 180) 100 parts Nonionic surfactant (Nonipol 400: manufactured by Sanyo Chemical Co., Ltd.) 5 parts Ion-exchanged water 200 parts The above ingredients are mixed to obtain a colorant dispersion (1 ) To prepare a colorant dispersant (3).

-Preparation of colorant dispersion (4)-
Carbon black (Mogal L: manufactured by Cabot) 50 parts Nonionic surfactant (Nonipol 400: manufactured by Sanyo Chemical Co., Ltd.) 5 parts Ion-exchanged water 200 parts The above ingredients are mixed together with the colorant dispersion (1) The same treatment was performed to prepare a colorant dispersant (4).

<Example 1a to Example 1d>
-Production of Toner 1-
Crystalline polyester resin particle dispersion B: 7.5 parts by mass Amorphous polyester resin particle dispersion E: 55.5 parts by weight Colorant dispersion (1): 5 parts by weight anionic surfactant (Dowfax 2A1 20% aqueous solution ): 4 parts by mass Release agent dispersion (1): 7 parts by mass First, in order to prepare core particles, a crystalline resin among the above raw materials was placed in a polymerization kettle equipped with a pH meter, a stirring blade, and a thermometer. A particle dispersion A, an amorphous resin particle dispersion E, an anionic surfactant and 100 parts by mass of ion-exchanged water were added and stirred at 140 rpm for 15 minutes. The colorant dispersion (1) and release agent dispersion (1) were added to and mixed with this, and then a 0.3 M nitric acid aqueous solution was added to the raw material mixture to adjust the pH to 4.8. Subsequently, 0.5 mass part of 10% nitric acid aqueous solution of polyaluminum chloride (manufactured by Asada Chemical Co., Ltd.) was added dropwise as an aggregating agent while applying shear force at 4000 rpm with Ultraturrax. Since the viscosity increased during the dropping of the flocculant, the dropping speed was reduced so that the flocculant was not biased to one place. After the dropping of the flocculant, the rotation speed was further increased to 5000 rpm and stirred for 5 minutes to mix the flocculant and the raw material mixture.

  A stirrer and a mantle heater were installed, and the temperature was raised to 40 ° C. at 1.0 ° C./min while appropriately adjusting the rotation speed of the stirrer so that the slurry of the raw material mixture was sufficiently stirred. After holding for 30 minutes, the temperature was raised at 0.1 ° C./minute, and the particle size was measured every 10 minutes with Multisizer II type (aperture diameter: 50 μm, manufactured by Beckman-Coulter). When the volume average particle diameter reached 5.0 μm, 25 parts by mass of the amorphous polyester resin dispersion E was added over 3 minutes for the shell layer. After holding for 30 minutes, the pH was adjusted to 8.0 using a 5% by mass aqueous sodium hydroxide solution. Thereafter, while adjusting the pH to 8.0 every 5.0 ° C., the temperature was raised to 85 ° C. at a temperature rising rate of 1 ° C./min and held at 85 ° C. When the particle shape and surface properties were observed every 30 minutes with an optical microscope and a scanning electron microscope (FE-SEM), the particles became almost spherical at 3.5 hours, so the temperature was lowered to 20 ° C. at 10 ° C./min. The particles were solidified. Thereafter, the reaction product was filtered, thoroughly washed with ion-exchanged water, and then dried using an air dryer. In this way, toner mother particles were obtained. To 100 parts by mass of the obtained toner base particles, 1 part by mass of silica particles is added as inorganic particles for external addition, and is added to a 5 L Henschel mixer (FM5C) manufactured by Mitsui Mining Co. A 1 μm toner 1a (cyan toner) was obtained. As the silica fine particles, particles having an average particle diameter of 110 nm that were granulated by a sol-gel method and subjected to a hydrophobization treatment with HMDS (hexamethyldisilazane) were used.

  Similarly, using the colorant dispersion liquids (2), (3), and (4) instead of the colorant dispersion liquid (1), the volume average particle diameter is 6.1 μm according to the above production conditions. Toner 1b (magenta toner), toner 1c (yellow toner) having a volume average particle diameter of 6.1 μm, and toner 1d (black toner) having a volume average particle diameter of 6.1 μm were obtained.

<Example 2>
-Production of Toner 2-
In preparation of the toner 1, the same operation was performed except that the crystalline polyester resin particle dispersion A was used in place of the crystalline polyester resin particle dispersion B in the preparation of the core particles, and a toner having a volume average particle diameter of 6.3 μm. 2 (cyan toner) was obtained.

<Example 3>
-Production of Toner 3-
In the production of toner 1, the same operation was performed except that the crystalline polyester resin particle dispersion H was used instead of the crystalline polyester resin particle dispersion B in the production of the core particles, and a toner having a volume average particle diameter of 6.1 μm. 3 (cyan toner) was obtained.

<Example 4>
-Production of Toner 4-
In preparation of the toner 1, the same operation was performed except that the crystalline polyester resin particle dispersion G was used in place of the crystalline polyester resin particle dispersion B in preparation of the core particles, and a toner having a volume average particle diameter of 6.3 μm. 4 (cyan toner) was obtained.

<Example 5>
-Production of Toner 5-
In the preparation of toner 1, in the preparation of the core particles, the addition amount of the crystalline polyester resin particle dispersion B is changed from 7.5 parts by mass to 3.8 parts by mass, and the addition amount of the amorphous polyester resin particle dispersion E is changed. A toner 5 (cyan toner) having a volume average particle diameter of 6.1 μm was obtained by performing the same operation as in the production of the toner 1 except that the amount was changed from 55.5 parts by mass to 59.2 parts by mass.

<Example 6>
-Production of Toner 6-
In the preparation of toner 1, in the preparation of the core particles, the addition amount of the crystalline polyester resin particle dispersion B is changed from 7.5 parts by mass to 15 parts by mass, and the addition amount of the amorphous polyester resin particle dispersion E is 55. A toner 6 (cyan toner) having a volume average particle diameter of 6.1 μm was obtained by performing the same operation as that of the toner 1 except that the amount was changed from 5 parts by mass to 48 parts by mass.

<Example 7>
-Production of Toner 7-
In the preparation of the toner 1, the same operations as in the preparation of the toner 1 except that the amorphous polyester resin particle dispersion F was used in place of the amorphous polyester resin particle dispersion E during the preparation of the core particles and the shell. And a toner 7 (cyan toner) having a volume average particle diameter of 6.0 μm was obtained.

<Example 8>
-Production of Toner 8-
In the preparation of the toner 1, 100 parts by mass of the obtained toner base particles are converted into hydrophobized silica particles having an average particle size of 110 nm, which are granulated by a sol-gel method and hydrophobized by HMDS as inorganic particles for external addition. Instead, the same operation as in the preparation of the toner 1 was performed except that hydrophobized silica particles having an average particle diameter of 300 nm that had been granulated by a sol-gel method and hydrophobized by HMDS were used, and the volume average particle diameter was 6.1 μm. Toner 8 (cyan toner) was obtained.

<Example 9>
-Production of Toner 9-
In the preparation of the toner 1, 100 parts by mass of the obtained toner base particles are converted into hydrophobized silica particles having an average particle size of 110 nm, which are granulated by a sol-gel method and hydrophobized by HMDS as inorganic particles for external addition. Instead, the same operation as in the preparation of the toner 1 was performed except that hydrophobized silica particles having an average particle diameter of 80 nm that had been granulated by the sol-gel method and hydrophobized by HMDS were used, and the volume average particle diameter was 6.1 μm. Toner 9 (cyan toner) was obtained.

<Comparative Example 1>
-Production of Toner 10-
In the preparation of toner 1, in the preparation of the core particles, the addition amount of the crystalline polyester resin particle dispersion A is changed from 7.5 parts by mass to 16.5 parts by mass, and the addition amount of the amorphous polyester resin particle dispersion E is changed. A toner 10 (cyan toner) having a volume average particle diameter of 6.3 μm was obtained in the same manner as in the preparation of the toner 1 except that the amount was changed from 55.5 parts by weight to 46.5 parts by weight.

<Comparative example 2>
-Production of Toner 11-
In preparation of the toner 1, in the preparation of the core particles, the addition amount of the crystalline polyester resin particle dispersion A is changed from 7.5 parts by mass to 3 parts by mass, and the addition amount of the amorphous polyester resin particle dispersion E is 55. A toner 8 (cyan toner) having a volume average particle size of 6.3 μm was obtained by performing the same operation as that of the toner 1 except that the amount was changed from 5 parts by mass to 60 parts by mass.

<Comparative Example 3>
-Production of Toner 12-
In preparation of the toner 1, the same operation was performed except that the crystalline polyester resin particle dispersion C was used in place of the crystalline polyester resin particle dispersion B in preparation of the core particles, and a toner having a volume average particle diameter of 6.1 μm. 12 (cyan toner) was obtained.

<Comparative example 4>
-Production of Toner 13-
In preparation of the toner 1, the same operation was performed except that the crystalline polyester resin particle dispersion D was used in place of the crystalline polyester resin particle dispersion B in preparation of the core particles, and a toner having a volume average particle diameter of 6.2 μm. 13 (cyan toner) was obtained.

<Comparative Example 5>
-Production of Toner 14-
In the preparation of the toner 1, 100 parts by mass of the obtained toner base particles are converted into hydrophobized silica particles having an average particle size of 110 nm, which are granulated by a sol-gel method and hydrophobized by HMDS as inorganic particles for external addition. Instead, the same operation as in the preparation of the toner 1 was performed except that hydrophobized silica particles having an average particle diameter of 65 nm that had been granulated by the sol-gel method and hydrophobized by HMDS were used, and the volume average particle diameter was 6.1 μm. Toner 14 (cyan toner) was obtained.

<Comparative Example 6>
-Production of Toner 15-
In the preparation of the toner 1, 100 parts by mass of the obtained toner base particles are converted into hydrophobized silica particles having an average particle size of 110 nm, which are granulated by a sol-gel method and hydrophobized by HMDS as inorganic particles for external addition. Instead, the same operation as in the preparation of the toner 1 was performed except that hydrophobized silica particles having an average particle diameter of 350 nm that had been granulated by the sol-gel method and hydrophobized by HMDS were used, and the volume average particle diameter was 6.1 μm. Toner 15 (cyan toner) was obtained.

<Creation of carrier>
Ferrite particles (volume average particle size: 35 μm) 100 parts by mass Toluene 14 parts by mass Methyl methacrylate-perfluoroacrylate copolymer (8: 2, Mw 66000, critical surface tension 24 dyn / cm) 1.6 parts by mass Carbon black (Product) Name: VXC-72, manufactured by Cabot Corp., resistance 100 Ωcm or less) 0.12 parts by mass Cross-linked melamine resin particles (volume average particle size; 0.3 μm, toluene insoluble) 0.3 parts by mass The above components excluding ferrite particles were added for 10 minutes. Dispersed with a stirrer to prepare a coating layer forming solution. Further, this coating layer forming solution and ferrite particles were put in a vacuum degassing type kneader and stirred at a temperature of 60 ° C. for 30 minutes, and then the pressure was reduced to distill off toluene to form a resin coating layer to obtain a carrier. (However, the carrier resin used was a perfluoroacrylate copolymer in which carbon black was diluted in toluene and dispersed with a sand mill.)

  The toner 1a to the toner 12 described above are mixed with 8 parts by mass of the toner 12 and 00 parts by mass of the carrier to prepare a two-component developer, and the electrostatic image developing developer 1a to the electrostatic image developing developer 12 are mixed. Obtained.

<Evaluation of transfer efficiency>
Using a DocuCentreColor f450 (made by Fuji Xerox Co., Ltd.) remodeling machine (process speed is set to 400 mm / s, and it has been remodeled so that it can operate as usual until transfer even if the fixing device is removed) shown in FIG. Then, 1000 sheets were output with the toner amount on the recording medium being 0.3 g / m ² , and after 1000 sheets, the toner amount on the recording medium was output at 4.0 g / m ² to evaluate the transfer efficiency. More specifically, two 1 cm × 1 cm latent images are prepared on a photoconductor, developed, and hard-stopped at the end of the transfer process, and the toner mass on the two intermediate transfer bodies is previously set in unit length. The weight per unit is transferred onto a known tape, the weight of the toner adhering tape is measured, and after subtracting the weight of the tape, the transferred toner amount a is obtained. Similarly, the amount of toner b remaining on the photoreceptor is determined. The transfer efficiency was determined by the following formula.

Transfer efficiency η (%) = a × 100 / (a + b)
The allowable range is 90% or more, and the closer to 100%, the better.

<Evaluation of developing machine contamination>
After completion of the evaluation of the transfer efficiency, the stain on the developing device was evaluated based on the toner scattering state of the developer exposed portion of the developing device. Evaluation was visually evaluated according to the following criteria.
○: There is almost no toner scattering and no problem
△: Inferior to ○ but slightly scattered toner, but not affected in actual use ×: Unsuitable due to extremely practical problems

<Evaluation of low-temperature fixability>
The developer of the DocuCenter Color f450 (Fuji Xerox Co., Ltd.) modified machine was filled with a developer, and an unfixed image was collected. The image conditions were a solid image of 40 mm × 50 mm, the toner amount was 3 g / m ² , and J paper (manufactured by Fuji Xerox Co., Ltd.) was used as the recording paper. Next, the fixing device of DocuPrint C2220 was modified so that the fixing temperature was variable, and the low-temperature fixing property of the image was evaluated while the fixing temperature was increased between 100 ° C. and 200 ° C. every 5 ° C. Note the low-temperature fixability, mold sticking by bending one minute at 20 g / cm ² after passed one hour after fixing a good fixed image free from image defects, the maximum width of the image defect of the bent portion becomes 0.4mm The temperature was taken as the minimum fixing temperature and used as an index for low-temperature fixability. The allowable temperature is 130 ° C. or lower, and the lower the better.

  The evaluation results are shown in Table 1.

  The image forming method and the image forming apparatus of the present invention are particularly useful for applications such as electrophotography and electrostatic recording.

1 is a schematic diagram illustrating an example of a configuration of an image forming apparatus used in an image forming method of the present invention.

Explanation of symbols

  200 Image forming apparatus, 400 housing, 401a to 401d electrophotographic photosensitive member, 402, 402a to 402d charging roll, 403 exposure device, 404, 404a to 404d developing device, 405a to 405d toner cartridge, 409 intermediate transfer belt, 410, 410a ˜410d Primary transfer roll, 411 tray (transfer medium tray), 413 secondary transfer roll, 414 fixing roll, 415a to 415d, 416 cleaning blade, 500 transfer medium.

Claims (4)

A toner for developing an electrostatic charge image, having core particles containing a crystalline polyester resin and a release agent, and a shell layer containing an amorphous polyester resin, and externally adding at least one kind of inorganic fine particles,
The crystalline polyester resin has a melting point Tm of 25 to 50 ° C., the content of the crystalline polyester resin is 5 to 20% by mass, and the average particle size of the inorganic fine particles is 80 to 300 nm. An electrostatic charge image developing toner characterized by:   An electrostatic charge image developing developer comprising the electrostatic charge image developing toner according to claim 1 and a carrier.   A step of charging the image carrier, a step of forming a latent image on the image carrier, and a step of developing the latent image on the latent image carrier using the developer for developing an electrostatic image according to claim 2. A primary transfer step of transferring the developed toner image onto the intermediate transfer member, a secondary transfer step of transferring the toner image transferred onto the intermediate transfer member to a recording medium, and the toner image with heat. An image forming method comprising: a step of fixing by pressure. An image carrier, a charging device for charging the image carrier, an exposure device for forming an electrostatic latent image on the image carrier charged by the charging device, and an electrostatic latent image on the image carrier. A developing device that forms a toner image; a primary transfer device that transfers the toner image to an intermediate transfer member; and a secondary transfer device that transfers the toner image transferred to the intermediate transfer member to a recording medium. ,
The image forming apparatus according to claim 1, wherein the toner forming the toner image is the toner according to claim 1.

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