JP4513627B2 - Electrostatic latent image developing toner, electrostatic latent image developer, and image forming method - Google Patents

Description

  The present invention relates to an electrostatic latent image developing toner, an electrostatic latent image developer, and an image forming method used when developing an electrostatic latent image formed in an electrophotographic process or the like.

  A number of methods are known as electrophotographic methods (see, for example, Patent Documents 1 and 2). In general, an electro latent image is formed on a photosensitive layer using a photoconductive substance by using various means. An exposure process to be formed, a process for developing a toner image using toner, a process for transferring the toner image to a recording material (recording medium) such as paper, and recording the toner image by heating, pressure, thermal pressure or solvent vapor It consists of basic processes such as a process of fixing to a material and a process of removing toner remaining on the photoreceptor layer.

  Currently, a fixing method using a heat roll (fixing roll) is most commonly used as a means for fusing and fixing toner on paper. As the heat roll, in order to prevent the toner from fusing to the heat roll when the toner is fixed by heat, the roll surface layer is coated with a material having a small surface energy such as a fluororesin. Was limited. Further, since these resins are worn or damaged by repeated use, the wettability of the surface of the fixing roll cannot be stably maintained for a long time. Furthermore, when the surface of the fixing roll is coated with such a resin, the thermal conductivity is deteriorated, which is disadvantageous for low-temperature fixing. Therefore, development of a toner that does not require coating the surface of the fixing roll with a fluorine-based resin or the like is desired.

With respect to the above, there are known examples in which the molecular weight of the binder resin in the toner is increased in order to improve the fixability and offset resistance (see, for example, Patent Documents 3 and 4). However, when a toner is produced by a kneading and pulverizing method, if a resin having an excessively high molecular weight is used, the viscosity of the resin used for production becomes severe because the viscosity increases when the raw material is melt-kneaded. As a result, the shape controllability also deteriorates.
In addition, if a chemical manufacturing method in which toner is manufactured in solution can be used, the shape of the toner can be controlled. Because of the rapid heat generation, it is difficult to control the reaction, and thus a toner containing a desired high molecular weight resin cannot be obtained.

  On the other hand, there is an example in which hot offset resistance is improved while maintaining low-temperature fixing with a toner having two peaks of molecular weight distribution using two types of resins (see, for example, Patent Document 5). However, with this technology, when the printed matter is stored, if a temperature near or above the glass transition point (Tg) is applied to the image, the low molecular weight resin component in the image portion melts and the back side of the printed matter or other printed matter There is a problem that image loss occurs due to adhesion to objects. In particular, in the case of light printing for the purpose of DTP or the like, double-sided printing or bookbinding is often performed, so the image portions are often left in contact with each other for a long time, and the printed matter is stored for a long time. In some cases, such as when a printed product is transported, there is a problem that image stability is poor and image defects are likely to occur.

  In recent years, a toner containing a crystalline resin as a binder resin has been reported in order to save energy by fixing the toner at a low temperature (see, for example, Patent Documents 6 and 7). This crystalline resin is characterized by a so-called sharp melt property in which the viscosity rapidly drops above a certain temperature. For this reason, the toner viscosity is significantly reduced above the melting point of the crystalline resin, thereby preventing hot offset. Is disadvantageous.

Therefore, a toner having a sea-island structure using an amorphous resin and a crystalline resin as a binder resin has been proposed (see, for example, Patent Documents 8 and 9). These toners maintain the low-temperature fixing by the crystalline resin domain, and realize the hot offset prevention by the amorphous resin. However, in this technique, when a hot roll having a high surface energy such as a metal roll is used for fixing, hot offset resistance is impaired.
US Patent 2,297,691 Japanese Patent Publication No.42-23910 JP-A-5-88403 JP 2003-76066 A JP 2004-109939 A Japanese Patent Laid-Open No. 2002-082485 JP 2000-352839 A JP 2001-42568 A JP 2004-46095 A

The present invention aims to solve the above problems.
That is, the present invention is excellent in releasability at the time of fixing and shape controllability at the time of toner production even when a metal roll not coated with a resin having high releasability is used as a fixing roll, and for storing and transporting printed matter In view of the above, an object is to provide a toner for developing an electrostatic latent image capable of forming an image having good stability over a long period of time against heat and load. It is another object of the present invention to provide an electrostatic latent image developer and an image forming method using the electrostatic latent image developing toner.

The above-mentioned subject is achieved by the following present invention. That is, the present invention
<1> An electrostatic latent image developing toner containing at least a binder resin and a colorant,
The binder resin includes a styrene / acrylic resin that is an amorphous resin and a polyester resin that is a crystalline resin, and the content of the polyester resin in the binder resin is in the range of 10 to 30% by mass, The ratio (Mw / AV) of the weight average molecular weight (Mw) and the acid value (AV) of the binder resin is in the range of 20000 to 35000, and the Z average molecular weight (Mz) is in the range of 500,000 to 1600000. Ri, and a shell containing a core and said styrene-acrylic-based resin containing the styrene-acrylic resin and the polyester resin, the weight average molecular weight of the styrene-acrylic resin (Mw) is Ru der 300000-600000 This is an electrostatic latent image developing toner.

<2> Disperse at least a crystalline resin particle dispersion obtained by dispersing polyester resin particles, which are crystalline resins having a volume average particle diameter of 1 μm or less, and styrene / acrylic resin particles, which are first amorphous resins. The first amorphous resin particle dispersion liquid and the colorant dispersion liquid in which the colorant is dispersed are mixed to form core aggregate particles, and the dispersion liquid in which the aggregate particles are dispersed is added to the second dispersion liquid. amorphous styrene-acrylic resin particles is a resin by mixing the second amorphous resin particle dispersion obtained by dispersing a styrene-acrylic is the second amorphous resin in the aggregated particles of <1> The electrostatic latent image developing toner according to <1>, wherein core / shell aggregated particles to which resin particles are adhered are formed, and the core / shell aggregated particles are heated to fuse and coalesce.

<3> An electrostatic latent image developer containing the electrostatic latent image developing toner according to <1> or <2>.

<4> At least a charging step for charging the surface of the image carrier, an electrostatic latent image forming step for forming an electrostatic latent image according to image information on the charged surface of the image carrier, and the surface of the image carrier Developing the electrostatic latent image formed on the surface with a developer containing toner to form a toner image, transferring the toner image formed on the surface of the image bearing member to the surface of the transfer object, Fixing the toner image formed on the surface of the recording medium on the surface of the recording medium using a metal roll composed of at least one selected from metals, alloys and metal oxides as a fixing roll; In an image forming method including:
In the image forming method, the toner is the electrostatic latent image developing toner according to <1> or <2>.

<5> The image forming method according to <4>, wherein an arithmetic average roughness Ra of the surface of the fixing roll is in a range of 0.1 to 5 μm.

<6> After the step of transferring the toner image to the surface of the transfer target, further including a step of removing residual toner on the surface of the image carrier after transfer with a cleaning blade,
The image forming method according to <4> or <5>, wherein a solid lubricant is supplied to the surface of the image carrier via a cleaning brush disposed upstream of the cleaning blade.

  According to the present invention, the peelability during fixing and the shape controllability during toner production are excellent, and the releasability from a metal roll is excellent, and from the viewpoint of storage and transportation of printed matter, , Electrostatic latent image developing toner capable of forming a stable image over a long period of time, a method for producing the same, an electrostatic latent image developer using the electrostatic latent image developing toner, and an image A forming method can be provided.

Hereinafter, the present invention will be described in detail.
<Toner for electrostatic latent image development>
The electrostatic latent image developing toner of the present invention (hereinafter sometimes simply referred to as “toner”) is an electrostatic latent image developing toner containing at least a binder resin and a colorant,
The binder resin includes a styrene / acrylic resin that is an amorphous resin and a polyester resin that is a crystalline resin, and the content of the polyester resin in the binder resin is in the range of 10 to 30% by mass, The ratio (Mw / AV) of the weight average molecular weight (Mw) and the acid value (AV) of the binder resin is in the range of 20000 to 35000, and the Z average molecular weight (Mz) is in the range of 500,000 to 1600000. Ri, and a shell containing a core and said styrene-acrylic-based resin containing the styrene-acrylic resin and the polyester resin, the weight average molecular weight of the styrene-acrylic resin (Mw) is Ru der 300000-600000 It is characterized by that.

  Usually, in a fixing step in electrophotography, a recording medium such as a paper or a transparent sheet having a toner image attached to the surface thereof is brought into contact with a heated fixing member, and the toner image (toner) is melted. Fix by infiltration. At this time, if the fixing temperature is low, the toner cannot be melted completely, and a phenomenon in which toner isolated from the fixed image adheres to the fixing roll, so-called cold offset occurs. Conversely, if the fixing temperature is too high, the toner is excessively melted. Phenomena in which viscosity decreases and intermolecular cohesion between toner constituent resin (binder resin) molecules weakens, and as a result, molecules whose cohesion is weaker than the adhesion force to the fixing roll migrates and adheres to the surface of the fixing roll. So-called hot offset occurs. Therefore, the temperature range higher than the temperature at which the cold offset occurs and lower than the temperature at which the hot offset occurs is the latitude of the fixable temperature.

  When using a roll that is not coated with a resin having high releasability, such as a solid metal roll, the above-mentioned latitude becomes a problem. In general, metal is a substance having high heat conductivity, and is easy to heat and cool. For this reason, when a recording medium such as paper is passed through a heated fixing roll during fixing, the temperature of the fixing roll decreases due to the contact between the recording medium and the fixing roll. Thereafter, the metal roll returns to the set temperature relatively quickly by heating. However, when the recording medium is continuously flowed, the temperature of the fixing roll is significantly lowered, which causes a cold offset. Therefore, when a metal roll is used as a fixing member in the fixing step, a wider fixing latitude than before is required.

  Here, when spreading the latitude to the low temperature side, it is necessary to use a toner containing a low-molecular-weight resin that is easily melted as a binder resin. However, in such a toner, the cohesive force between molecules in the binder resin is weak, and resistance is high. The hot offset property is difficult, and the strength of the fixed image is also weak. Accordingly, there is a demand for development of a toner with the latitude extended to the high temperature side while maintaining the lower limit of the conventional fixing latitude.

  In order to widen the fixing latitude to the high temperature side, it is necessary to increase the cohesion between molecules in the binder resin constituting the toner, that is, to increase the molecular weight of the binder resin. However, as described above, the toner containing the desired high molecular weight resin cannot be obtained by the kneading and pulverizing method or the suspension polymerization method. In the emulsion polymerization method, there is an example in which a toner containing a high molecular weight resin is prepared using two types of resins. In this case, since both types use a vinyl resin, a low molecular weight is also included in a fixed image. It is considered that the resin component is uniformly dispersed. Therefore, when a temperature higher than the glass transition point of the resin is applied to the fixed image, the high molecular weight resin component has high intermolecular force and low mobility (昜 deformability), but the low molecular weight resin component has high mobility, and this low molecular weight If the resin component is present in the vicinity of the image, the image stability is poor, resulting in an image defect.

  In the present invention, by using a high molecular weight amorphous resin that has sufficient intermolecular cohesive force and a crystalline resin having sharp melt properties, the minimum fixing temperature does not increase, and It has been found that a toner having good releasability at the time of fixing can be obtained even for a metal roll not coated with an amorphous resin having high releasability. Further, it was found that the crystalline resin soaks into the paper at the time of fixing and does not exist in the vicinity of the surface of the fixed image, so that it can provide a stable fixed image that does not cause image loss even after long-term storage.

  Specifically, as described above, in the toner of the present invention, an amorphous resin and a crystalline resin are used as the binder resin, and the content of the crystalline resin in the binder resin is 10 to 30% by mass. The ratio of the weight average molecular weight (Mw) of the binder resin to the resin acid value (AV) (Mw / AV) is in the range of 20000 to 35000, and the Z average molecular weight (Mz) is in the range of 500,000 to 1600000. By setting the range, the excellent fixing property and image storability were obtained, and the present invention was completed.

Hereinafter, the structure of the electrostatic latent image developing toner of the present invention will be described in order.
(Binder resin)
-Amorphous resin-
In the present invention, the amorphous resin is one having only a stepwise endothermic change, not a clear endothermic peak, in a thermal analysis measurement using differential scanning calorimetry (DSC). It refers to those that are thermoplasticized at temperatures above that.

First, as the amorphous resin used in the present invention, at least a styrene / acrylic resin can be used, and other known resin materials can be used including other resins used in combination . For example, styrenes such as styrene, parachlorostyrene, α-methylstyrene; methyl acrylate, ethyl acrylate, butyl acrylate, propyl acrylate, lauryl acrylate, ethyl hexyl acrylate, methyl methacrylate, ethyl methacrylate, methacryl Esters having a vinyl group such as butyl acid, propyl methacrylate, lauryl methacrylate, ethyl hexyl methacrylate, vinyl acetate, vinyl benzoate; carboxylic acids having a double bond such as methyl maleate, ethyl maleate, butyl maleate Olefins such as ethylene, propylene, butylene, and butadiene; carboxylic acids having a double bond such as acrylic acid, methacrylic acid, and maleic acid; polymerized alone, or copolymerized by combining two or more of these Further it can be mixtures thereof.

  Furthermore, epoxy resins, polyester resins, polyurethane resins, polyamide resins, cellulose resins, polyether resins, etc., non-vinyl condensation resins, or a mixture of these with the above vinyl resins, or vinyl monomers in the presence of these resins Examples thereof include graft polymers obtained upon polymerization.

  The amorphous resin in the present invention may contain a dissociable vinyl monomer together with the monomer constituting the amorphous resin during the polymerization in order to control the degree of polymerization. The dissociative vinyl monomer is a raw material for polymer acids and polymer bases such as acrylic acid, methacrylic acid, maleic acid, cinnamic acid, fumaric acid, vinylsulfonic acid, ethyleneimine, vinylpyridine, and vinylamine. Any monomer can be used. Polymer acids are preferred because of the ease of polymer formation reaction, among others, dissociable vinyl monomers having a carboxyl group such as acrylic acid, methacrylic acid, maleic acid, cinnamic acid and fumaric acid are preferred. It is preferable from the viewpoint of control and control of the glass transition point. In addition, these dissociative vinyl monomers can be copolymerized and used at the time of polymerization of an amorphous resin.

  In the case of the vinyl monomer, a resin particle dispersion can be prepared by carrying out emulsion polymerization or seed polymerization using an ionic surfactant or the like. In the case of other resins, if the resin is oily and dissolves in a solvent having a relatively low solubility in water, the resin is dissolved in those solvents, and an ionic surfactant and / or in water. It is preferable to dissolve the polymer electrolyte and to disperse the particles together in water with a disperser such as a homogenizer. Then, it is good to prepare a resin particle dispersion by heating or depressurizing to evaporate the solvent.

  In the present invention, the ratio (Mw / AV) of the weight average molecular weight (Mw) and resin acid value (AV) of the binder resin is 20000 to 35000, and the Z average molecular weight (Mz) is in the range of 500,000 to 1600000. However, the weight average molecular weight (Mw), resin acid value (AV) and Z average molecular weight (Mz) of the amorphous resin are largely reflected in the Mw / AV and Mz of the binder resin in the present invention. The Therefore, in order for the binder resin to satisfy the above conditions, the amorphous resin basically satisfies the above conditions.

  Therefore, Mw / AV of the amorphous resin in the present invention needs to be in the range of 20000 to 35000, but a more preferable range is 22000 to 33000, and a particularly preferable range is 22000 to 30000. Mw / AV represents the distribution of polar groups in the resin. When Mw / AV is smaller than 20000, that is, when the resin polarity is increased, the affinity with the metal is increased and the hot offset resistance is deteriorated. On the other hand, if Mw / AV is larger than 35000, the granulation property and shape controllability of the toner particles are deteriorated.

The weight average molecular weight Mw of the amorphous resin in said Ri range der of 300000 to 600000, more preferably in the range of 300,000 to 500,000, more preferably in the range of 300,000 to 400,000.
If Mw is less than 300,000, plasticization is likely to occur and offset may not be prevented. If it exceeds 600,000, normal fixing may not be performed.

Furthermore, it is necessary that the amorphous resin has a Z average molecular weight (Mz) of 500,000 to 16,00000. Mz mainly represents the distribution of the high molecular weight component in the resin molecular weight distribution, and this distribution is important because it reflects the toughness of the molten toner at the time of peeling. When Mz is less than 500,000, the hot offset resistance is deteriorated, and when it is more than 1600000, the granulation property of the toner particles is remarkably deteriorated.
In addition, Mz in this invention has the preferable range of 600000-1400000, and the range of 70000-1200000 is more preferable.

  The measurements of Mw and Mz were performed under the following conditions using gel permeation chromatography (GPC). 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. The measurement conditions were a sample concentration of 0.5% and a flow rate of 0.6 ml / min. Sample injection volume 10 μl, measurement temperature 40 ° C., using 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 ”.

  When measuring the Mw and Mz of the binder resin contained in the toner described later, the toner is dissolved in THF so as to have the above concentration, and after removing insoluble components such as a colorant with a filter paper, The same measurement as described above was performed.

The acid value (AV) is measured by weighing 2 g of an amorphous resin and dissolving it in 160 ml of tetrahydrofuran, or dissolving it if it is insufficiently soluble, and then using this sample, JIS K0070-1992. The acid value was measured by potentiometric titration.
In addition, when the acid value of the binder resin contained in a toner to be described later is obtained using the toner described later, it can be measured in the same manner as described above.

  In the toner of the present invention, a chain transfer agent can be used during the polymerization of the amorphous resin. Although there is no restriction | limiting in particular as a chain transfer agent, The compound which has a thiol component can be used. Specifically, alkyl mercaptans such as hexyl mercaptan, heptyl mercaptan, octyl mercaptan, nonyl mercaptan, decyl mercaptan, and dodecyl mercaptan are preferred, and in particular, the molecular weight distribution is narrow, so that the storage stability of the toner at high temperature is improved. preferable.

The amorphous resin in the present invention can be produced by radical polymerization of a polymerizable monomer.
There is no restriction | limiting in particular as an initiator for radical polymerization used here. Specifically, hydrogen peroxide, acetyl peroxide, cumyl peroxide, tert-butyl peroxide, propionyl peroxide, benzoyl peroxide, chlorobenzoyl peroxide, dichlorobenzoyl peroxide, bromomethylbenzoyl peroxide, lauroyl peroxide Ammonium persulfate, sodium persulfate, potassium persulfate, diisopropyl peroxycarbonate, tetralin hydroperoxide, 1-phenyl-2-methylpropyl-1-hydroperoxide, tert-butyl hydroperoxide pertriphenyl acetate, tert-butyl formate, Peroxides such as tert-butyl peracetate, tert-butyl perbenzoate, tert-butyl perphenylacetate, tert-butyl permethoxyacetate, tert-butyl perN- (3-toluyl) carbamate, 2,2 '-Azobispro Bread, 2,2′-dichloro-2,2′-azobispropane, 1,1′-azo (methylethyl) diacetate, 2,2′-azobis (2-amidinopropane) hydrochloride, 2,2 ′ -Azobis (2-amidinopropane) nitrate, 2,2'-azobisisobutane, 2,2'-azobisisobutyramide, 2,2'-azobisisobutyronitrile, 2,2'-azobis-2- Methyl methylpropionate, 2,2′-dichloro-2,2′-azobisbutane, 2,2′-azobis-2-methylbutyronitrile, dimethyl 2,2′-azobisisobutyrate, 1,1′-azobis (1 -Methylbutyronitrile-3-sodium sulfonate), 2- (4-methylphenylazo) -2-methylmalonodinitrile, 4,4'-azobis-4-cyanovaleric acid, 3,5-dihydroxymethylphenyl Zo-2-methylmalonodinitrile, 2- (4-bromophenylazo) -2-allylmalonodinitrile, 2,2'-azobis-2-methylvaleronitrile, 4,4'-azobis-4-cyanoyoshi Dimethyl herbate, 2,2′-azobis-2,4-dimethylvaleronitrile, 1,1′-azobiscyclohexanenitrile, 2,2′-azobis-2-propylbutyronitrile, 1,1′-azobis-1 -Chlorophenylethane, 1,1'-azobis-1-cyclohexanecarbonitrile, 1,1'-azobis-1-cycloheptanenitrile, 1,1'-azobis-1-phenylethane, 1,1'-azobiscumene, 4-Nitrophenylazobenzylcyanoacetate ethyl, phenylazodiphenylmethane, phenylazotriphenylmethane, 4-nitrophenylazotrif Nylmethane, 1,1′-azobis-1,2-diphenylethane, poly (bisphenol A-4,4′-azobis-4-cyanopentanoate), poly (tetraethylene glycol-2,2′-azobisiso) Azo compounds such as butyrate), 1,4-bis (pentaethylene) -2-tetrazene, 1,4-dimethoxycarbonyl-1,4-diphenyl-2-tetrazene and the like.

During the polymerization, the amount of the polymerization initiator mainly affects the control of the molecular weight, and generally the molecular weight increases when the amount of the polymerization initiator is decreased.
In the present invention, in order to set Mw / AV and Mz in the above ranges, the polymerization initiator amount is preferably in the range of 0.3 to 1.0% by mass in the total amount of the polymer raw material, A range of 1.0% by mass is more preferable.

Further, by using a large aliphatic chain having about 10 to 40 carbon atoms as the crosslinking agent, it is possible to broaden the molecular weight distribution to the high molecular weight region and to suppress the thickening of the resin.
As such an aliphatic crosslinking agent, (meth) acrylic acid esters of linear polyhydric alcohols, (meth) acrylic acid esters of substituted polyhydric alcohols; polyvinyl esters of polycarboxylic acids are used. be able to.

  Specific examples include polyethylene glycol # 200 glycol diacrylate, polyethylene glycol # 400 glycol diacrylate, polyethylene glycol # 600 glycol diacrylate, polyethylene glycol # 1000 glycol diacrylate, 1,10-decanediol diacrylate, and the like.

  The preferable content of the crosslinking agent is preferably in the range of 0.05 to 5% by mass, more preferably in the range of 0.1 to 1.0% by mass in the total amount of the polymer raw material.

  In addition, it is preferable that the glass transition temperature of the amorphous resin in this invention is the range of 45-60 degreeC, and it is more preferable that it is the range of 50-60 degreeC. When the glass transition temperature is less than 45 ° C., the toner tends to easily block during storage or in the developing device (a phenomenon in which toner particles are aggregated into a lump). On the other hand, if the glass transition temperature exceeds 60 ° C., the fixing temperature of the toner becomes high, which is not preferable.

-Crystalline resin-
The crystalline resin in the present invention refers to a resin having a clear endothermic peak rather than a stepwise endothermic amount change in differential scanning calorimetry (DSC).
At least a polyester resin is used as the crystalline resin . Specific examples of resins including other resins used in combination include crystalline polyester resins and crystalline vinyl resins. Fixing and charging properties on paper at the time of fixing, and adjusting the melting point within a preferred range From this point of view, a crystalline polyester resin is preferable. A linear aliphatic crystalline polyester resin having an appropriate melting point is more preferable.

  The crystalline polyester resin is synthesized from an acid (dicarboxylic acid) component and an alcohol (diol) component. In the present invention, a copolymer obtained by copolymerizing other components in a proportion of 50% by mass or less with respect to the crystalline polyester main chain is also referred to as a crystalline polyester resin.

  The method for producing the crystalline polyester resin is not particularly limited, and can be produced by a general polyester polymerization method in which an acid component and an alcohol component are reacted. Examples thereof include direct polycondensation and transesterification. Depending on the type of monomer, it can be used separately.

  The production of the crystalline polyester resin can be carried out at a polymerization temperature of 180 to 230 ° C., and the reaction is carried out while reducing the pressure in the reaction system as necessary to remove water and alcohol generated during condensation. When the monomer is not dissolved or compatible with the reaction temperature, a solvent having a high boiling point may be added as a solubilizer and dissolved. In the polycondensation reaction, the dissolution auxiliary solvent is distilled off. In the case where a monomer having poor compatibility exists in the copolymerization reaction, it is preferable to condense the monomer having poor compatibility with the monomer and the acid or alcohol to be polycondensed in advance and then polycondense together with the main component.

  Catalysts that can be used in the production of the crystalline polyester resin include alkali metal compounds such as sodium and lithium; alkaline earth metal compounds such as magnesium and calcium; metals such as zinc, manganese, antimony, titanium, tin, zirconium, and germanium Compound: Phosphorous acid compound, phosphoric acid compound, amine compound and the like.

  Specifically, for example, sodium acetate, sodium carbonate, lithium acetate, lithium carbonate, calcium acetate, calcium stearate, magnesium acetate, zinc acetate, zinc stearate, zinc naphthenate, zinc chloride, manganese acetate, manganese naphthenate, titanium Tetraethoxide, titanium tetrapropoxide, titanium tetraisoproxide, titanium tetrabutoxide, antimony trioxide, triphenylantimony, tributylantimony, tin formate, tin oxalate, tetraphenyltin, dibutyltin dichloride, dibutyltin oxide, diphenyltin oxide, zirconium Tetrabutoxide, zirconium naphthenate, zirconyl carbonate, zirconyl acetate, zirconyl stearate, zirconyl octylate, germanium oxide, Li phenyl phosphite, tris (2, 4-t-butylphenyl) phosphite, ethyltriphenylphosphonium bromide, triethylamine, compounds such as triphenyl amine.

  Specific examples of the crystalline polyester resin thus produced and usable in the present invention include poly-1,2-cyclopropene dimethylene isophthalate, polydecamethylene adipate, polydecamethylene azelate, polydecamethylene. Oxalate, polydecane methylene sebacate, polydecamethylene succinate, polyeicosamethylene malonate, polyethylene-p- (carbophenoxy) butyrate, polyethylene-p- (carbophenoxy) undecanoate, polyethylene-p-phenylene diacetate, Polyethylene sebacate, polyethylene succinate, polyhexamethylene carbonate, polyhexamethylene-p- (carbophenoxy) undecanoate, polyhexamethylene oxalate, polyhexamethylene sebacate, Li hexamethylene suberate, polyhexamethylene succinate, poly-4,4-isopropylidene diphenylene adipate, poly-4,4-isopropylidene diphenylene malonate, and the like.

Further, trans-poly-4,4-isopropylidene diphenylene-1-methylcyclopropane dicarboxylate, polynonamethylene azelate, polynonamethylene terephthalate, polyoctamethylene dodecanediate, polypentamethylene terephthalate, trans-poly -M-phenylene cyclopropane dicarboxylate, cis-poly-m-phenylene cyclopropane dicarboxylate, polytetramethylene carbonate, polytetramethylene-p-phenylene diacetate, polytetramethylene sebacate, polytrimethylene dodecanedioate , Polytrimethylene octadecandioate, polytrimethylene oxalate, polytrimethylene undecandioate, poly-p-xylene adipate, poly-p-xylene azease Over DOO, poly -p- xylene sebacate, poly glycol terephthalate, cis - poly-1,4 (2-butene) sebacate, polycaprolactone and the like.
A copolymer of a plurality of ester monomers used in these polymers, a copolymer of the ester monomers and other monomers copolymerizable therewith, and the like can also be used.

  Among the crystalline polyester resins described above, the crystalline polyester resin having an alkylene group having 6 or more carbon atoms is selected from the viewpoints of fixability to paper at the time of fixing, chargeability, and ease of adjustment of the melting point range. Preferably used. The carbon number is more preferably as described above.

The melting point of the crystalline resin in the present invention is preferably 40 ° C. or higher, and more preferably 60 ° C. or higher. However, as an upper limit, 100 degrees C or less is preferable and 90 degrees C or less is more preferable. In particular, the melting point of the crystalline resin is preferably in the range of 60 to 95 ° C. for low temperature fixability.
When the melting point of the crystalline resin is lower than 40 ° C., the toner may be blocked during storage or use of the toner. On the other hand, when the melting point of the crystalline resin is higher than 100 ° C., the low-temperature fixability may not be achieved.

  In the present invention, the melting point of the crystalline resin is measured by ASTM D3418- when the differential scanning calorimeter (DSC) is used and the temperature is measured from room temperature to 150 ° C. at a heating rate of 10 ° C. per minute. 8 can be obtained as a melting peak temperature of differential thermal analysis measurement based on 8. In the above measurement, a plurality of melting peaks may be shown. In the present invention, the maximum peak temperature is regarded as the melting point.

The molecular weight of the crystalline resin is not particularly limited, but the weight average molecular weight is preferably 8000 or more, and more preferably 10,000 or more. However, 100000 or less is preferable and 70000 or less is more preferable. If the weight average molecular weight of the crystalline resin is less than 8000, there is a risk that the strength of the fixed image will be insufficient, or crushing may occur while stirring the developing device. Further, if the weight average molecular weight of the crystalline resin is larger than 100,000, the fixing temperature may be increased.
The molecular weight can be measured in the same manner as the molecular weight measurement method for the binder resin and amorphous resin.

  In the toner of the present invention, the content of the crystalline resin needs to be 10 to 30% by mass in the binder resin, preferably 15 to 30% by mass, and 20 to 25% by mass. More preferred. If the content of the crystalline resin is less than 10% by mass, the amount is insufficient to serve as a fixing bridge between the paper and the high molecular weight amorphous resin, and sufficient image strength can be obtained. Absent. On the other hand, when the content of the crystalline resin exceeds 30% by mass, the low molecular weight crystalline resin is exposed on the toner surface and the hot offset resistance is deteriorated.

  In the toner of the present invention, it is desirable that the amorphous resin and the crystalline resin are appropriately compatible. If the amorphous resin and the crystalline resin are completely compatible with each other, the toner viscosity may decrease too much at the time of melting, and the hot offset resistance may deteriorate. If the two are completely incompatible with each other, the crystalline resin is not taken into the toner and is discharged to the surface (rejection). As a result, the charging / powder / fixing characteristics of the toner are adversely affected. There is a case.

(Coloring agent)
As the colorant in the present invention, known organic or inorganic pigments and dyes, and oil-soluble dyes can be used.
For example, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 57: 1, C.I. I. Pigment red 122, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 180, C.I. I. Pigment yellow 185, C.I. I. Pigment blue 15: 1, C.I. I. Pigment Blue 15: 3, Lamp Black (C.I.No. 77266), Rose Bengal (C.I.No. 45432), Carbon Black, Nigrosine Dye (C.I.No. 50415B), Metal Complex Dye, Metal Derivatives of complex salt dyes and mixtures thereof can be mentioned.

Furthermore, various metal oxides such as silica, aluminum oxide, magnetite and various ferrites, cupric oxide, nickel oxide, zinc oxide, zirconium oxide, titanium oxide, and magnesium oxide, and mixtures thereof can be used. The colorant to be used is selected from the viewpoints of hue angle, saturation, brightness, weather resistance, OHP permeability, and dispersibility in the toner.
The content of the colorant depends on the toner particle size and the development amount, but is appropriately in the range of 1 to 50 parts by mass with respect to 100 parts by mass of the binder resin. In particular, a range of 2 to 25 parts by mass is preferable.

These colorants can be used alone or in combination and further in the form of a solid solution. These colorants are dispersed by a known method, and for example, a rotary shear type homogenizer, a media type dispersing machine such as a ball mill, a sand mill, or an attritor, a high-pressure opposed collision type dispersing machine, or the like is preferably used.
Further, when these colorants are used in the emulsion aggregation method described later, a polar surfactant is used and dispersed in an aqueous system by the homogenizer.

(Other ingredients)
As described above, the component constituting the toner of the present invention is not particularly limited as long as it contains at least a binder resin containing a crystalline resin and an amorphous resin and a colorant. In addition, other components such as a release agent may be included.

Specific examples of the release agent used in the present invention include the following.
For example, as waxes and waxes, plant waxes such as carnauba wax, cotton wax, wood wax, rice wax, animal waxes such as beeswax and lanolin, mineral waxes such as ozokerite and cercin, paraffin, microcrystalline, Petroleum waxes such as petrolatum. In addition to these natural waxes, synthetic hydrocarbon waxes such as Fischer-Tropsch wax and polyethylene wax, fatty acid amides such as 12-hydroxystearic acid amide, stearic acid amide, phthalic anhydride imide, and chlorinated hydrocarbon, esters, Synthetic waxes such as ketones and ethers can also be used.

  Furthermore, other mold release agents include homopolymers or copolymers of polyacrylates such as poly-n-stearyl methacrylate and poly-n-lauryl methacrylate (for example, n-stearyl acrylate / ethyl methacrylate copolymer, etc.) And the like, and crystalline polymers having a long alkyl group in the side chain. Among these, more preferable are petroleum waxes such as paraffin wax and microcrystalline wax, and synthetic waxes.

  The content of the releasing agent is preferably in the range of 10 to 40% by mass, more preferably in the range of 10 to 30% by mass, further preferably in the range of 15 to 30% by mass, and 15 to 25%. A mass% range is particularly preferred. If the content rate of a mold release agent is 10 mass% or more, sufficient release property can be ensured and generation | occurrence | production of a hot offset can be prevented. On the other hand, if it is 40% by mass or less, the release agent is not exposed to the toner surface, and good fluidity and chargeability can be obtained.

In addition, if necessary, a lubricant or a charge control agent may be added to the toner of the present invention.
Examples of the lubricant that can be used include fatty acid amides such as ethylene bisstearylamide and oleic acid amide, and fatty acid metal salts such as zinc stearate and calcium stearate.

  The charge control agent is added to improve and stabilize the chargeability. For example, a dye composed of a complex such as a quaternary ammonium salt compound, a nigrosine compound, aluminum, iron, or chromium, or a triphenylmethane type Various commonly used charge control agents such as pigments can be used, but this affects the stability of the aggregated particles in the aggregation process and fusion / unification process when the toner is prepared by the emulsion aggregation method described later. From the standpoint of controlling ionic strength and reducing wastewater contamination, materials that are difficult to dissolve in water are preferred.

  In particular, as the charge control agent, metal salts of benzoic acid, metal salts of salicylic acid, metal salts of alkyl salicylic acid, metal salts of catechol, metal-containing bisazo dyes, tetraphenylborate derivatives, and the like used in powder toners. A compound selected from the group consisting of a quaternary ammonium salt and an alkylpyridinium salt, and a combination thereof can be preferably used.

  Further, when inorganic particles are added to the toner in a wet manner as a charge control agent, examples of such inorganic particles include silica, alumina, titania, calcium carbonate, magnesium carbonate, tricalcium phosphate, etc. Listed are all inorganic particles used as additives. In this case, these inorganic particles can be used by being dispersed in a solvent using an ionic surfactant, a polymer acid, a polymer base, or the like.

Further, in the toner of the present invention, inorganic particles or organic particles can be added to the surface by applying a shearing force in a dry state for the purpose of use as a flow aid or a cleaning aid.
Examples of the inorganic particles include all particles usually used as external additives on the toner surface, such as silica, alumina, titania, calcium carbonate, magnesium carbonate, tricalcium phosphate, and cerium oxide. Examples of the organic particles include all particles used as an external additive on a normal toner surface such as vinyl resin, polyester resin, and silicone resin.

  When each of the above materials is used as an external additive, the total amount of the external additive is preferably 2% by mass or more, more preferably 3% by mass or more based on the whole toner. When the amount is less than 2% by mass, there may be insufficient voids between the toner particles, and sufficient release of the release agent may not be obtained. The upper limit of the total amount of external additives is preferably 10% by mass or less, more preferably 8% by mass or less, based on the total toner.

  The volume average particle size of the toner in the present invention is preferably in the range of 4 to 10 μm, more preferably in the range of 5 to 8 μm, and still more preferably in the range of 5.5 to 7.5 μm. When the volume average particle size is less than 4 μm, the chargeability becomes insufficient and the developability may be deteriorated. When it exceeds 10 μm, the resolution of the image may be deteriorated.

Further, as the particle size distribution index of the toner, it is preferable that the volume average particle size distribution index GSDv is 1.30 or less and the number average particle size distribution index GSDp is 1.40 or less. Further, the ratio GSDv / GSDp between the volume average particle size distribution index GSDv and the number average particle size distribution index GSDp is preferably 0.95 or more.
If the volume average particle size distribution index GSDv exceeds 1.30, or the number average particle size distribution index GSDp exceeds 1.40, the resolution of the image is reduced, and if GSDv / GSDp is less than 0.95, In some cases, a drop may occur, and at the same time, it may scatter and cause image defects such as fogging.

The volume average particle size and the particle size distribution index are the particle size ranges (channels) obtained by dividing the particle size distribution measured by using Coulter Unter TAII (manufactured by Beckman-Coulter). The cumulative distribution is subtracted, the particle size that becomes 16% cumulative is the volume D16v, the number D16p, the particle size that becomes the cumulative 50% is the volume D50v (this is referred to as “volume average particle size”), the number D50p, the cumulative 84% Are defined as a volume D84v and a number D84p. Then, the volume particle size distribution index GSDv is calculated as ^1/2 (D84v / D16v), the number average particle size distribution index GSDp is calculated as ^1/2 (D84p / D16p).
The measurement is performed after the toner is dispersed in an electrolyte aqueous solution (isoton aqueous solution) and dispersed by ultrasonic waves for 30 seconds or more.

In addition, the shape factor SF1 of the toner of the present invention is preferably set to 120 ≦ SF1 ≦ 135 from the viewpoint of improving developability and transfer efficiency and improving image quality. This shape factor SF1 is obtained by the following equation (1).
SF1 = (ML ² / A) × (π / 4) × 100 (1)
In the above formula (1), ML represents the maximum length of each particle, and A represents the projected area of each particle.

  When the shape factor SF1 is less than 120, residual toner is generally generated in the transfer process during image formation. Therefore, it is necessary to remove the residual toner. However, the cleaning property when cleaning the residual toner with a blade or the like is improved. It is easy to damage and may result in image defects. On the other hand, when the shape factor SF1 exceeds 135, when the toner is used as a developer, the toner may be destroyed due to collision with a carrier in the developing device. At this time, as a result, the amount of fine powder increases or the release agent component exposed on the toner surface may contaminate the surface of the photosensitive member and the like, and the charging characteristics may be impaired. May cause problems.

  The average value of the shape factor SF1 is obtained by taking 50 or more toner images magnified 250 times from an optical microscope into an image analyzer (LUZEX III, manufactured by Nireco), and calculating the individual values from the maximum length and projected area. The value of SF1 for the particles is obtained and averaged.

In the toner of the present invention, the surface property index value represented by the following formula (2) is preferably 2 or less.
(Surface property index value) = (actual value of specific surface area) / (calculated value of specific surface area) (2)
However, in the above formula, the calculated specific surface area is represented by 6Σ (n × R ² ) / {ρ × Σ (n × R ³ )}, where n is the Coulter counter. II represents the number of particles in the channel (number / channel), R represents the channel particle size (μm) in the Coulter counter, and ρ represents the toner density (g / μm ³ ). The number of divisions of the channel is 16. The size of the division is 0.1 interval on the log scale.

  Here, the surface property index value is preferably 2 or less, more preferably 1.8 or less. If it exceeds 2, the smoothness of the toner surface is impaired, and when an external additive is externally added to the toner surface, the external additive may be buried and the chargeability may be lowered.

Incidentally, the specific surface area calculated value was determined by measuring the particle size of each channel of the Coulter Counter II and the number of particles of the particle size, as shown in the formula representing the specific surface area calculated value, and converting each particle into a sphere. The particle size distribution was taken into account.
Moreover, the specific surface area actual measurement value is measured based on the gas adsorption / desorption method, and is obtained by obtaining the Langmuir specific surface area. As a measuring device, Coulter SA3100 type (manufactured by Coulter, Inc.), Gemini 2360/2375 (manufactured by Shimadzu Corporation), or the like can be used.

  Hereinafter, the method for producing the toner of the present invention will be described. The method for producing the toner of the present invention is not particularly limited, but in order to use a binder resin having an Mw within the above range for toner production, it is practically produced by the method described below (emulsion polymerization aggregation method). It is desirable to do.

  That is, in the toner of the present invention, a crystalline resin particle dispersion obtained by dispersing crystalline resin particles having a volume average particle size of 1 μm or less, and a first amorphous resin obtained by dispersing first amorphous resin particles. The resin particle dispersion and the colorant dispersion obtained by dispersing the colorant are mixed to form the first aggregated step of forming the core aggregated particles; A second amorphous resin particle dispersion in which crystalline resin particles are dispersed is mixed to form core / shell aggregated particles in which the second amorphous resin particles are adhered to the aggregated particles. The agglomeration step is preferably performed through a process including at least a fusion / union step in which the core / shell agglomerated particles are heated and fused / unified to be fused / unioned.

  In the first and second aggregating steps, it is preferable to generate agglomeration between particles by changing pH to prepare agglomerated particles. At the same time, an aggregating agent may be added to stably and rapidly aggregate the particles, or to obtain aggregated particles having a narrower particle size distribution.

  As the flocculant, a compound having a monovalent or higher charge is preferable, and specific examples of the compound include water-soluble surfactants such as the above-mentioned ionic surfactants and nonionic surfactants, hydrochloric acid, sulfuric acid, Acids such as nitric acid, acetic acid, oxalic acid, magnesium chloride, sodium chloride, aluminum sulfate, calcium sulfate, ammonium sulfate, aluminum nitrate, silver nitrate, copper sulfate, sodium carbonate and other inorganic acid metal salts, sodium acetate, potassium formate, oxalic acid Aliphatic acids such as sodium, sodium phthalate and potassium salicylate, metal salts of aromatic acids, metal salts of phenols such as sodium phenolate, metal salts of amino acids, triethanolamine hydrochloride and aniline hydrochloride And inorganic acid salts of aromatic amines.

  In consideration of the stability of the aggregated particles, the stability of the coagulant with respect to heat and time, and the removal during washing, a metal salt of an inorganic acid is preferable as the coagulant in terms of performance and use. Specific examples include metal salts of inorganic acids such as magnesium chloride, sodium chloride, aluminum sulfate, calcium sulfate, ammonium sulfate, aluminum nitrate, silver nitrate, copper sulfate, and sodium carbonate.

  The amount of these flocculants added varies depending on the valence of the charge, but they are all small, in the case of monovalent, about 3% by mass or less of the entire agglomeration system, in the case of divalent, about 1% by mass or less, In the case of trivalent, it is about 0.5% by mass or less. Since the amount of the flocculant is preferably small, it is preferable to use a compound having a large valence.

Further, for example, a surfactant can be used for the purpose of stabilizing the dispersion of the resin particle dispersion, the colorant dispersion, and the release agent dispersion.

Examples of the surfactant include anionic surfactants such as sulfate ester, sulfonate, phosphate, and soap; cationic surfactants such as amine salt type and quaternary ammonium salt type; polyethylene glycol type And nonionic surfactants such as alkylphenol ethylene oxide adducts and polyhydric alcohols. Among these, an ionic surfactant is preferable, and an anionic surfactant and a cationic surfactant are more preferable.

  In general, an anionic surfactant has a strong dispersibility and is excellent in dispersing resin particles and colorants. Further, it is advantageous to use an anionic surfactant as a surfactant for dispersing the release agent.

  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 be used in combination of 2 or more type.

  Specific examples of anionic surfactants include fatty acid soaps such as potassium laurate, sodium oleate, and castor oil sodium; sulfates such as octyl sulfate, lauryl sulfate, lauryl ether sulfate, and nonyl phenyl ether sulfate; lauryl sulfonate , Sodium alkylnaphthalene sulfonate such as dodecylbenzene sulfonate, triisopropyl naphthalene sulfonate, dibutyl naphthalene sulfonate; sulfone such as naphthalene sulfonate formalin condensate, monooctyl sulfosuccinate, dioctyl sulfosuccinate, lauric acid amide sulfonate, oleic acid amide sulfonate Acid salts; lauryl phosphate, isopropyl phosphate, nonylphenyl ether Phosphoric acid esters such as Sufeto; dialkyl sulfosuccinate salts such as sodium dioctyl sulfosuccinate; sulfosuccinate salts such as sulfosuccinate lauryl disodium; and the like.

  Specific examples of the cationic surfactant include laurylamine hydrochloride, stearylamine hydrochloride, oleylamine acetate, stearylamine acetate, stearylaminopropylamine acetate, and other amine salts; lauryltrimethylammonium chloride, dilauryldimethylammonium Chloride, distearyldimethylammonium chloride, distearyldimethylammonium chloride, lauryldihydroxyethylmethylammonium chloride, oleylbispolyoxyethylenemethylammonium chloride, lauroylaminopropyldimethylethylammonium ethosulphate, lauroylaminopropyldimethylhydroxyethylammonium perchlorate, alkylbenzene Trimethylammonium chloride, Quaternary ammonium salts such as quilts trimethyl ammonium chloride; and the like.

  Specific examples of the nonionic surfactant include alkyl ethers such as polyoxyethylene octyl ether, polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether; polyoxyethylene octyl phenyl ether, polyoxy Alkyl phenyl ethers such as ethylene nonyl phenyl ether; alkyl esters such as polyoxyethylene laurate, polyoxyethylene stearate, polyoxyethylene oleate; polyoxyethylene lauryl amino ether, polyoxyethylene stearyl amino ether, polyoxyethylene Alkylamines such as oleyl amino ether, polyoxyethylene soybean amino ether, polyoxyethylene beef tallow amino ether; Alkyl amides such as ethylene lauric acid amide, polyoxyethylene stearic acid amide, polyoxyethylene oleic acid amide; vegetable oil ethers such as polyoxyethylene castor oil ether and polyoxyethylene rapeseed oil ether; lauric acid diethanolamide, stearic acid Alkanolamides such as diethanolamide and oleic acid diethanolamide; sorbitan ester ethers such as polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan monooleate And so on.

  The content of the surfactant in each dispersion may be a level that does not inhibit the present invention, and is generally a small amount. Specifically, it is about 0.01 to 10% by mass of the entire aggregate system. It is a range, More preferably, it is the range of 0.05-5 mass%, More preferably, it is the range of about 0.1-2 mass%. When the content is less than 0.01% by mass, each dispersion such as a resin particle dispersion, a colorant dispersion, and a release agent dispersion becomes unstable, so that aggregation occurs, and each particle during aggregation There are problems such as the release of specific particles due to the difference in stability between them, and when the amount exceeds 10% by mass, the particle size distribution of the particles becomes wide, and the control of the particle size becomes difficult. It is not preferable for the reason. In general, a suspension polymerization toner dispersion having a large particle size is stable even if the amount of the surfactant used is small.

In addition, a polyvalent carboxylic acid can be used for the purpose of preventing fusion between the toners while controlling the shape of the toner during the fusion and coalescence process. Polycarboxylic acids such as those listed below are presumed to act as protective films that adhere to the surface of the toner and prevent fusion between the toners as well as adjusting the pH of the solution to the value necessary for toner shape control. The
Specific examples of polyvalent carboxylic acids include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, maleic acid, fumaric acid, phthalic acid, isophthalic acid, terephthalic acid Acid, citric acid, malic acid, trimellitic acid and the like can be mentioned.

Next, details of a preferred production example of the toner of the present invention will be described.
In the first aggregation step, first, a crystalline resin particle dispersion, a first amorphous resin particle dispersion, a colorant particle dispersion, and a release agent particle dispersion are prepared. The crystalline resin particle dispersion is heated by a known phase inversion emulsification or higher than the melting point of the crystalline resin and emulsified by mechanical shearing force. At this time, the emulsion may be stabilized by adding a surfactant or by self-neutralization using a neutralized amine. As for the first amorphous resin particle dispersion, the first amorphous resin particles prepared by the same method as the crystalline resin particle dispersion or emulsion polymerization are used with an ionic surfactant. It can be prepared by dispersing in a solvent. The colorant particle dispersion is prepared by dispersing colorant particles of a desired color in a solvent using an ionic surfactant having a polarity opposite to that of the ionic surfactant used in the preparation of the resin particle dispersion. . In addition, the release agent particle dispersion allows the release agent to be dispersed in water together with a polymer electrolyte such as an ionic surfactant, a polymer acid, or a polymer base, heated above the melting point, and subjected to strong shearing. It is prepared by granulating with a homogenizer or a pressure discharge type disperser.
In the present invention, at least a polyester resin is used as the crystalline resin, and at least a styrene / acrylic resin is used as the first amorphous resin and the second amorphous resin described later.

  Next, the crystalline resin particle dispersion, the first amorphous resin particle dispersion, the colorant particle dispersion, and the release agent particle dispersion are mixed, and the crystalline resin particles and the first non-crystalline resin dispersion are mixed. Aggregated particles (core aggregated particles) comprising resin particles, colorant particles, and release agent particles having a diameter substantially close to a desired toner diameter by hetero-aggregating crystalline resin particles, colorant particles, and release agent particles ).

  In the second aggregating step, the second non-crystalline resin particle dispersion containing the second non-crystalline resin particles is used on the surface of the core agglomerated particles obtained in the first aggregating step. Aggregated particles (core / shell agglomerated particles) having a core / shell structure in which a shell layer is formed on the surface of the core agglomerated particles by attaching crystalline resin particles to form a coating layer (shell layer) having a desired thickness. Get. Note that the second amorphous resin particles used at this time may be the same as or different from the first amorphous resin particles.

  The particle diameters of the crystalline resin particles, the first amorphous resin particles, the second amorphous resin particles, the colorant particles, and the release agent particles used in the first and second aggregating steps are as follows. In order to easily adjust the diameter and the particle size distribution to desired values, it is preferably 1 μm or less, and more preferably in the range of 100 to 300 nm.

  In the first aggregation step, the balance of the amounts of the two polar ionic surfactants (dispersants) contained in the crystalline resin particle dispersion, the first amorphous resin particle dispersion, and the colorant particle dispersion. Can be shifted in advance. For example, an inorganic metal salt such as calcium nitrate or a polymer of an inorganic metal salt such as polyaluminum chloride is ionically neutralized and heated below the glass transition temperature of the first amorphous resin particles. Thus, core agglomerated particles can be produced.

  In such a case, in the second agglomeration step, the second amorphous resin particle dispersion treated with a polar and amount dispersing agent that compensates for the balance between the two polar dispersing agents, The core / shell is added to the solution containing the core agglomerated particles and, if necessary, slightly heated below the glass transition temperature of the core agglomerated particles or the second amorphous resin particles used in the second agglomeration step. Aggregated particles can be produced.

  In the core / shell structure of the aggregated particles, the thickness of the shell layer is not particularly limited, but is preferably in the range of 150 to 300 nm. If the thickness of the shell layer is less than 150 nm, the release agent may flow out to the toner surface, and the released release agent may contaminate the photoreceptor or the like as a result. Further, if the thickness of the shell layer exceeds 300 nm, the viscosity in the slurry system in the step of forming the core aggregated particles decreases, and the number of second amorphous resin particles added at the time of shell formation increases rapidly. In some cases, the viscosity of the slurry in the system greatly increases, and the particle size and particle size distribution may deteriorate during shell formation. In addition, particles are easily generated during the shell formation, and toner manufacturing problems such as clogging when the toner slurry containing such residual resin particles is solid-liquid separated and removed with a filter or the like are likely to occur. There is a case.

  In addition, the 1st and 2nd aggregation process may be repeatedly performed in several steps dividedly.

  Next, in the fusion / unification process, the core / shell aggregated particles obtained through the second aggregation process are mixed with amorphous resin particles (shell layer) contained in the core / shell aggregated particles in a solution. Glass transition temperature (including the constituent resin) (the glass transition temperature of the resin having the highest glass point transition temperature when there are two or more types of resin), and the melting point of the crystalline resin when a crystalline resin is included. The toner particles are obtained by heating above the highest temperature and fusing and coalescing.

After completion of the coalescence / union process, toner particles are obtained by drying the toner formed in the solution through a known washing process, solid-liquid separation process, and drying process.
In addition, it is preferable that the washing | cleaning process performs substitution washing | cleaning by ion-exchange water fully from a charging point. The solid-liquid separation step is not particularly limited, but suction filtration, pressure filtration, and the like are preferably used from the viewpoint of productivity. Further, although the drying process is not particularly limited, freeze drying, flash jet drying, fluidized drying, vibration fluidized drying and the like are preferably used from the viewpoint of productivity.

<Electrostatic latent image developer>
The electrostatic latent image developer of the present invention is not particularly limited except that it contains the toner for developing an electrostatic latent image of the present invention, and can have an appropriate component composition depending on the purpose. The electrostatic latent image developer of the present invention is a one-component electrostatic latent image developer when the electrostatic latent image developing toner of the present invention is used alone, and a two-component system when used in combination with a carrier. The electrostatic latent image developer.

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

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

  Examples of the coating resin for the resin-coated carrier include styrenes such as styrene, parachlorostyrene, and α-methylstyrene; methyl acrylate, ethyl acrylate, n-propyl acrylate, lauryl acrylate, acrylic acid 2 -Α-methylene fatty acid monocarboxylic acids such as ethylhexyl, methyl methacrylate, n-propyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate; nitrogen-containing acrylics such as dimethylaminoethyl methacrylate; acrylonitrile, methacrylonitrile, etc. Vinyl nitriles; vinyl pyridines such as 2-vinyl pyridine and 4-vinyl pyridine; vinyl ethers such as vinyl methyl ether and vinyl isobutyl ether; vinyl methyl ketone, vinyl ethyl ketone, vinyl isopropenyl Homopolymers such as vinyl ketones such as ketones; olefins such as ethylene and propylene; vinyl-based fluorine-containing monomers such as vinylidene fluoride, tetrafluoroethylene and hexafluoroethylene; and copolymers comprising two or more types of monomers Furthermore, silicone resins containing methyl silicone, methyl phenyl silicone, etc., polyesters containing bisphenol, glycol, etc., epoxy resins, polyurethane resins, polyamide resins, cellulose resins, polyether resins, polycarbonate resins and the like can be mentioned. These resins may be used alone or in combination of two or more. The coating amount of the coating resin is preferably in the range of about 0.1 to 10 parts by mass, more preferably in the range of 0.5 to 3.0 parts by mass with respect to 100 parts by mass of the core particles.

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

  The mixing ratio of the electrostatic latent image developing toner of the present invention and the carrier in the two-component electrostatic latent image developer is not particularly limited, and can be appropriately selected according to the purpose.

<Image forming method>
Next, an image forming method using the toner of the present invention will be described.
The image forming method of the present invention includes a charging step for charging the surface of the image carrier, an electrostatic latent image forming step for forming an electrostatic latent image according to image information on the charged surface of the image carrier, and the image A developing step of developing the electrostatic latent image formed on the surface of the carrier with toner to form a toner image, a transfer step of transferring the toner image formed on the surface of the image carrier to the surface of the transfer member, An image including at least a fixing step in which the toner image transferred to the surface of the recording material is fixed using a metal roll having a surface selected from a metal, an alloy, and a metal oxide as a fixing roll. In the forming method, the toner of the present invention described above is used as the toner.

  Therefore, in the image forming method of the present invention, the toner of the present invention having extremely excellent peelability is used even when a high surface energy hot roll such as a metal roll is used for fixing. It is excellent in releasability from the fixing member that comes into contact, and it is possible to prevent the occurrence of problems such as occurrence of hot offset and deterioration in image quality of images obtained after fixing.

  The metal roll as the fixing roll may have a roll configuration in which a SUS material or an Al material, which is a core metal material of a conventional fixing roll (resin-coated roll), is exposed as it is. Specifically, the material of the metal roll is not particularly limited as long as it is a material having excellent mechanical strength and good thermal conductivity. For example, aluminum, SUS, iron, copper, brass, etc. A metal, an alloy, etc. are mentioned.

  In addition, this metal roll has a high durability and thermal conductivity as its surface material, for example, a metal such as Fe, Cr, Cu, Ni, Co, Mn, Al, and a material obtained by mixing these oxides alone or in combination. It may be coated with.

  By using such a metal roll as a fixing roll, durability such as strength of the roll and abrasion resistance is improved and thermal conductivity is good, so that thermal efficiency is improved. In other words, the metal roll is much more resistant than the one with a low surface energy material typified by fluororesin or silicone resin on the surface of the member that comes into contact with the toner image, such as a fixing roll having general wear resistance. To improve.

  Further, in a general fixing roll, it is necessary to introduce a filler and cure the release layer in order to maintain strength against a fixing roll contact type release assisting mechanism represented by a peeling claw. Furthermore, in order to suppress electrostatic offset due to the electrical resistance of the fixing roll, it is necessary to disperse a conductive material in the release layer.

  On the other hand, since the metal roll has hardness and conductivity in the roll itself, there is no need to bother reinforcing the strength and imparting conductivity. This means that there is no need for complicated repeating steps such as coating, drying, and polishing over a number of layers as in the case of a general fixing roll. From the viewpoint of environmental impact, as mentioned above, it is possible to reduce the environmental impact by reducing manufacturing energy by simplifying the process, and because it does not use low surface energy materials typified by fluororesin and silicone resin, it also burns. Fluoride etc. are not generated by disposal. Further, it is not necessary to separate the fixing roll and the release layer, and the disposal process can be simplified. Furthermore, from the viewpoint of recycling and reuse, since it is a metal, at least material recycling is possible. Moreover, it can be reused again as a fixing roll if it is given some surface cleaning / polishing.

  In the metal roll, the arithmetic average roughness Ra of the surface that directly contacts the unfixed toner image surface is preferably in the range of 0.01 to 5.0 μm, more preferably in the range of 0.10 to 4.0 μm. . When the surface roughness Ra is less than 0.01 μm, high-temperature offset may occur, although it is advantageous with respect to melting unevenness and gloss on the fixed image surface.

  Here, the offset phenomenon is generally divided into what is called a high temperature offset and what is called a low temperature offset. The high temperature offset is caused by adhesion of melted toner to the heat fixing roll, and the low temperature offset is not melted. This is because the toner particles adhere to the heat fixing roll, and is determined by the distribution state of the surface temperature of the heat fixing roll, the contact area with the toner image surface, the toner characteristics, and the like.

  For this reason, when the arithmetic average roughness Ra of the fixing roll surface is less than 0.01 μm, the following may be considered as the cause of the high temperature offset. One is that when the fixing agent is interposed between the fixing roll surface and the toner image surface at the time of fixing, the fixing roller surface is a mirror surface, so that the releasing agent cannot sufficiently exist on the toner image surface and the high temperature offset. Can be estimated. This is because there is almost no unevenness on the surface of the fixing roll, so that the releasing agent cannot be held on the fixing roll and the releasing agent does not function sufficiently. On the other hand, regarding the releasability of the toner image, it can be estimated that a high temperature offset has occurred due to an increase in contact area and contact state between the fixing roll surface and the toner image surface. When fixing rolls with different surface roughness are considered, the contact surface between the fixing roll surface and the toner image surface has a larger contact area per unit area or the same contact area as the surface roughness is smoother. It is considered that since the individual contact surfaces are large, the peeling force increases, which is disadvantageous for peeling and causes high temperature offset.

  On the other hand, when the arithmetic average roughness Ra on the surface of the fixing roll is larger than 5.0 μm, the release agent retaining property and the contact area / contact state work advantageously with respect to the high temperature offset for the reasons described above. However, problems occur in terms of roughness and gloss on the surface of the fixed image, and problems such as a uniform image surface cannot be obtained with respect to gloss and color when two or more color toners are stacked and fixed. Sometimes.

The processing method of the arithmetic average roughness Ra on the surface of the fixing roll is not particularly limited, but general surface processing methods such as cutting and blast polishing can be used.
The arithmetic average roughness Ra is measured using a surface roughness meter surfcom 1400A (manufactured by Tokyo Seimitsu Co., Ltd.) according to JIS B 0601-1994, with a measuring length of 4.0 mm and a cutoff value of 0.8 mm. The measurement speed was 0.30 mm / sec, and the inclination correction was performed under the conditions of the least square straight line correction.

  In the present invention, it is preferable that the image surface after the fixing step has an arithmetic average roughness Ra of 0.1 μm or more and an average interval Sm of unevenness of 0.5 mm or less. More preferably, Ra is 1 μm or more and the unevenness average interval Sm is 0.3 mm or less. If Ra is smaller than 0.1 μm, even if a metal roll is used, a minute slip may occur during double-sided image formation, which may cause image quality degradation or image quality defect. On the other hand, if the average unevenness interval Sm is larger than 0.5 mm, the uniformity on the image may be impaired and recognized as image unevenness.

Note that the image surface roughness Ra and the average interval Sm of the irregularities were determined according to JIS B 0601-1994. When obtaining the image surface roughness Ra, the cut-off value and the evaluation length are required for the measurement, and the reference length and the evaluation length are required for the average interval Sm of the unevenness. In the present invention, the image surface roughness Ra and the average interval Sm of the unevenness are not fixed because the values vary depending on the samples, and the standard values described in JIS B 0601-1994 are adopted for each sample. For the surface roughness Ra and the average interval Sm of the irregularities, values when the ranges are appropriate were adopted.
These values were obtained by scanning 15 patches of an image patch of 3 cm × 4 cm created by the image forming apparatus using an image roughness measuring apparatus (Laser Scanning Microscope: manufactured by OLS1100 Olympus Co., Ltd.), and taking the average as the measured value.

  Thus, by setting the arithmetic average roughness Ra of the image surface after the fixing step to 0.1 μm or more and the unevenness average interval Sm to 0.5 mm or less, uneven gloss and uneven image can be suppressed, and the result is good. Gloss and image quality can be obtained. This is because by managing the arithmetic average roughness Ra and the average interval Sm on the image, the surface of the image is made uniform (or made uniform) with a fine area and unevenness becomes inconspicuous.

  Here, the production of the structure is not achieved by simply specifying the roughness of the fixing roll surface. For example, even if the surface roughness of a general fixing roll coated with a fluororesin is processed to Ra 0.1 μm or more and the average interval Sm of unevenness is processed to 0.5 mm or less, the fixed image surface is out of roughness and uneven average interval. This is considered as follows. When a low surface energy material such as a fluororesin is used, a portion that does not slip locally on the image at the time of fixing is formed. As a result, a flat part and a part with slightly strong unevenness are formed.

  However, the above problem does not occur when a metal roll is used as the fixing roll as in the present invention. The reason is considered as follows. The surface-uncoated metal roll has a higher surface energy than the fluororesin. At the time of fixing a normal toner, the toner in a molten state is sandwiched between paper (OHP or the like) and a low surface energy material-covered fixing roll and is crushed from both sides and then pulled. Immediately after the end of fixing (at the time of peeling), the effect of the low surface energy material greatly increases the pulling force on the paper side and the fixing ends. At this time, a minute slip is repeated at the paper-fixing roll interface. When a metal roll is used, the toner on the fixing roll side is pulled during peeling because the surface energy of the metal itself is large. As a result, the slip does not occur, and as a result, uniform unevenness can be formed on the toner surface. Even if a metal roll having a high surface energy is used, the unevenness can be created without offset because the toner of the present invention is used. This is because the toner has a fixing release function as described above.

  For example, the range of Ra and Sm in the fixed image can be controlled by processing the surface of the metal roll. Unlike the case of a general fixing roll, this can be achieved by setting the arithmetic average roughness Ra of the metal roll surface to 0.01 to 5.0 μm as described above. This is because the surface roughness of the fixing roll does not become a mirror image as it is, but by changing the contact area between the surface of the fixing roll and the toner image surface at the time of fixing, the arithmetic average roughness Ra and the unevenness average interval Sm in the image can be obtained. It is thought to change.

  The image forming method of the present invention is not particularly limited as long as it includes at least the charging step, the electrostatic latent image forming step, the developing step, the transfer step, and the fixing step as described above. A process may be included. In the present invention, when a toner image is directly transferred from a photoreceptor to a sheet or the like, the sheet (recorded body) is a transferred body. However, when an intermediate transfer body is used for full color image formation. The intermediate transfer member is also included in the transfer target.

  In the present invention, the method further includes a step of removing residual toner on the surface of the image carrier after the transfer by a cleaning blade after the step of transferring the toner image to the surface of the transfer member, and is disposed at an upstream position of the cleaning blade. It is preferable that a solid lubricant is supplied to the surface of the image carrier through the cleaning brush.

  As a method for cleaning the surface of the photosensitive member, a method in which a cleaning blade made of rubber or the like is brought into contact with the photosensitive member is generally used. However, since the photosensitive member is worn at the cleaning unit, the photosensitive member is worn as the number of image formation increases. Since the amount increases, even when the photoconductor is used, image quality defects due to pinhole leaks gradually increase and sometimes the desired life is not achieved.

  In particular, when a print having a high image density is used for a long period of time, the amount of photoconductor wear at the portion corresponding to the image portion increases because the toner and external additives, etc. intervening between the photoconductor and the blade contact portion at the cleaning portion increase. The degree of wear increases, and the degree of shaving becomes larger than that of the non-image portion, and pinhole leak in the image portion is likely to become obvious.

  The above tendency becomes particularly remarkable when the toner using the binder resin having a high molecular weight according to the present invention is used. The reason for this is that the toner surface of the present invention is hard and the surface of the photoconductor is easy to scrape, and the adhesion of the external additive to the toner surface is difficult to make uniform. This is because it is more likely to occur.

  In the present invention, as described above, the cleaning blade is disposed upstream of the cleaning blade in the photosensitive member rotation direction, and the mechanism for supplying the solid lubricant from the cleaning brush to the surface of the photosensitive member is provided. It is possible to reduce the generation and wear of scratches at the contact portion between the photosensitive member and the photoconductor, and to reduce the amount of photoconductor wear at the image portion.

Below, the mechanism for performing the said cleaning process is demonstrated using drawing.
FIG. 1 is a schematic configuration diagram showing a main part of a printer (image forming apparatus) to which an embodiment of an image forming method of the present invention is applied. As shown in FIG. 1, the printer 1 includes a photoconductor (image carrier) 110, a charger 120, an exposure device 130, developing devices 140Y, 140M, 140C, and 140K in a main body housing 10. A cleaning device 150, an intermediate transfer belt 210, a primary transfer device 220, a secondary transfer device 230, a belt cleaning device 240, a fixing device 250, and a paper tray 260 are provided and configured.

  The photoreceptor 110 is an electrophotographic photoreceptor having an undercoat layer formed on a conductive substrate and a photosensitive layer formed on the undercoat layer, and the undercoat layer has a blocking (charge injection control) capability. And a conductive dispersion layer having both a resistance value adjusting function and a resistance value adjusting ability are used. The photoconductor 110 corresponds to an example of an image carrier in the present invention.

  The printer 1 is capable of full-color printing, and symbols Y, M, C, and K added to the end of the developing devices 140Y, 140M, 140C, and 140K are yellow, magenta, cyan, And a developer for forming a black toner image.

A basic operation in image formation of the printer 1 will be described.
First, as a preparation for forming an image, the belt cleaning device 240 and the secondary fixing device 230 are retracted to a predetermined position away from the intermediate transfer belt 210. Further, the photoconductor 110 rotates in the direction of arrow A, and a predetermined charge is applied to the surface of the photoconductor 110 by the contact charger 120 (charging process).

Subsequently, image data representing a color separation image obtained by separating the image into yellow, magenta, cyan, and black is given to the exposure device 130, and the image forming process is started. First, a yellow toner image is formed as follows.
The exposure device 130 irradiates the surface of the photoconductor 110 with exposure light corresponding to a yellow color separation image to form an electrostatic latent image (electrostatic latent image) (electrostatic latent image forming step). The electrostatic latent image is developed with a yellow toner contained in the developer circulated and supplied by the developing device 140Y by a developing voltage applied to a developing position between the developing device 140Y and the photosensitive member 110, and A yellow toner image is formed on the photoreceptor 110 (development process). The toner image is transferred to an intermediate transfer belt (transfer object) 160 by a primary transfer device 220 (transfer process). When the yellow toner image is transferred onto the intermediate transfer belt 210, the residual toner remaining on the photoconductor 110 is scraped off and removed by the cleaning device 150 (cleaning step). The cleaning device 150 will be described in detail later.

  Further, the intermediate transfer belt 210 is circulated and moved in the direction of arrow B by the drive roll 211, and is synchronized with the timing when the yellow toner image transferred onto the intermediate transfer belt 210 returns to the position of the primary transfer device 220. The magenta toner image is formed so that the magenta toner image of the next color reaches the primary transfer unit 220. The magenta toner image formed in this way is transferred onto the yellow toner image on the intermediate transfer belt 210 by the primary transfer unit 220.

  Subsequently, the residual toner on the photoconductor 110 is removed by the cleaning device 150, and cyan and black toner images are formed at the same timing as described above. Yellow and magenta toners are formed on the intermediate transfer belt 210 by the primary transfer device 220. The toner image is further transferred onto the toner image.

  When the multi-color toner image is transferred onto the intermediate transfer belt 210 in this way, the belt cleaning device 240 and the secondary fixing device 230 are moved to a position in contact with the intermediate transfer belt 210 and are stored in the paper feed tray 260. The paper (recorded medium) 300 is conveyed toward the secondary fixing device 230 by the conveyance roll 261. The multicolor toner image transferred onto the intermediate transfer belt 210 is secondarily transferred onto the recording paper 300 by the secondary fixing device 230 (transfer process). Residual toner remaining on the intermediate transfer belt 210 after the secondary transfer is scraped off by the belt cleaning device 240.

  The multicolor toner image transferred onto the recording paper 300 is conveyed to the fixing device 250 together with the recording paper 300, and is fixed onto the recording paper 300 by the fixing device 250 (fixing step). A color image is formed by a series of processes as described above.

Next, a mechanism for supplying a solid lubricant to the photoreceptor in the cleaning device 150 shown in FIG. 1 will be described.
FIG. 2 is a schematic sectional view of the cleaning device 150 in FIG. The cleaning device shown in FIG. 2 has a configuration in which residual toner on the surface of the image carrier 110 is processed with a rotating brush (cleaning brush) 2 and scraped off with a cleaning blade 3. Are in contact. The solid lubricant 4 is held by the regulating member 6, the solid lubricant 4 is scraped by the rotating brush 2, and the shaved solid lubricant is applied to the image carrier 110. The residual toner scraped off by the cleaning blade 3 is sent to the toner conveying auger section 5 by the rotating brush 2 and collected.

  FIG. 3 is a schematic view showing a contact state between the solid lubricant holding form and the rotating brush. The solid lubricant 4 is held by the regulating member 6 and is configured to contact the rotating brush 2. As shown in the figure, the regulating member 6 is fixed to the housing (not shown) by the regulating member support portions 6a and 6b, so that the solid lubricant 4 is always kept against the rotary brush 2 similarly supported by the housing. The amount of biting is constant in the axial direction.

As the solid lubricant, a fatty acid metal salt, particularly zinc stearate having a cleavage property and a high effect of improving releasability, can be used to form a more effective film. Other fatty acid metal salts include metal salts such as cadmium, barium, lead, iron, nickel, cobalt, copper, aluminum and magnesium stearate; dibasic lead stearate; zinc oleate, magnesium, iron and cobalt Metal salts such as palmitic acid, aluminum and calcium; lead caprylate; lead caproate; zinc linoleate; cobalt linoleate; calcium ricinoleate; ricinoleic acid and zinc, cadmium, etc. Metal salts; and mixtures thereof. Furthermore, a higher alcohol represented by solidified CH ₃ (CH ₂ ) _x CH ₂ OH (wherein x is an integer of 18 to 68) can be used.

  As a material of the cleaning brush used in the image forming method of the present invention, a known material can be used. Among them, nylon, acrylic or polypropylene is preferable, and among these, nylon is particularly excellent in long-term stability. preferable. The fiber thickness of the brush surface is preferably in the range of 2 to 17 denier, more preferably in the range of 3 to 10 denier. By setting the fiber thickness within the above range, the solid lubricant is scraped off and applied to the photoreceptor.

The fiber length on the brush surface (not including the raised adhesive layer thickness) is preferably in the range of 2.5 mm to 7 mm, and more preferably in the range of 3 mm to 6.5 mm. By setting the fiber length within the above range, the solid lubricant is scraped off and applied to the photoreceptor. The fiber density on the brush surface is preferably in the range of 15 × 10 ³ to 200 × 10 ³ fibers / inch ² (23.4 to 310 fibers / mm ² ), more preferably 20 × 10 ³ to 80 × 10 ³ fibers. / Inch ² (31.0 to 124 / mm ² ). It is preferable to make the fiber density within the above range because a uniform lubricant can be applied over a long period of time.

Furthermore, the photoreceptor used in the present invention has a conductive substrate, an undercoat layer formed on the conductive substrate, and a photosensitive layer formed on the undercoat layer. Is preferably formed from a coating solution prepared by subjecting metal oxide particles to a surface treatment using at least one coupling agent and then dispersing them in a binder resin. The film resistance of the coating film is preferably set to 10 ⁴ to 10 ¹³ Ω · cm. If the resistance value is too low, sufficient leakage resistance cannot be obtained, and if it is too high, the residual potential is increased. The resistance value can be controlled by controlling the resistance value of the metal oxide particles themselves and the amount of the metal oxide particles added to the binder resin, and the dispersibility of the metal oxide particles in the binder resin. As the volume resistance value of the metal oxide particles, those in the range of 10 ² to 10 ¹¹ Ω · cm can be used, and those in the range of 10 ⁴ to 10 ¹⁰ Ω · cm are particularly desirable.

The said metal oxide particle is disperse | distributed in binder resin and the coating liquid for undercoat layer formation is obtained. The undercoat layer obtained by using this coating liquid is volume resistivity is in the range of 10 ⁴ ~10 ¹³ Ω · cm is available, the range of particularly 10 ⁹ ~10 ¹² Ω · cm Things are desirable.

  In addition, the thicker the undercoat layer, the easier it is to prevent the effect of the penetrating substance from the outside, so that the leakage resistance is improved. A thin film having a thickness of, for example, 10 μm or less does not have sufficient leakage resistance. On the other hand, if the film thickness is too thick, it is difficult to form a uniform film, and image quality is likely to deteriorate due to an increase in residual charge. Therefore, the thickness of the undercoat layer is set in a range exceeding 15 μm, and more preferably in a range of 20 to 50 μm.

  FIG. 4 shows a schematic cross-sectional view of a photoreceptor using the undercoat layer. A conductive substrate 50, an undercoat layer 60 formed on the conductive substrate, and a photosensitive layer formed on the undercoat layer 60. The photosensitive layer includes a charge generation layer 71 and a charge transport layer. 72 and a two-layer structure. FIG. 5 shows a schematic cross-sectional view of a general organic photoreceptor. The difference from FIG. 4 is that the thickness of the undercoat layer is very thin.

  In the image forming method of the present invention described above, since the toner of the present invention that is extremely excellent in releasability from the metal roll at the time of fixing is used, the releasability from the fixing member that comes into contact with the toner image during fixing is improved. It is possible to prevent problems such as excellent, hot offset, and deterioration of image quality of an image obtained after fixing.

  Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples. However, the present invention is not limited to the following examples and comparative examples. In the following description, “part” represents “part by mass” and “%” represents “% by mass” unless otherwise specified.

<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 a Coulter Counter TA-II type (manufactured by Beckman-Coulter) as the measuring device, and ISOTON-II (manufactured by 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 of 2 to 60 μm is measured using the Coulter counter TA-II type with an aperture diameter of 100 μm. The volume average particle diameter, GSDv, and GSDp were determined as described above. The number of particles to be measured was 50,000.

(Toner shape factor SF1 measurement method)
The toner shape factor SF1 is obtained by taking an optical microscope image of the toner spread on the slide glass into a Luzex image analyzer through a video camera, calculating SF1 for 50, and obtaining an average value. This shape factor SF1 is obtained by the following equation (1).
SF1 = (ML ² / A) × (π / 4) × 100 (1)
In the above formula (1), ML represents the maximum length of each particle, and A represents the projected area of each particle.

(Measurement method of molecular weight and molecular weight distribution of resin)
In the present invention, the molecular weight and molecular weight distribution of the amorphous resin and the binder resin are those obtained 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 ”.

(Volume average particle diameter of resin particles, colorant particles, etc.)
Volume average particle diameters of resin particles, colorant particles, and the like were measured with a laser diffraction particle size distribution measuring apparatus (LA-700, manufactured by Horiba, Ltd.).

(Measuring method of melting point and glass transition temperature of resin)
The glass transition point (Tg) of the amorphous resin and the melting point (Tm) of the crystalline resin were measured using a differential scanning calorimeter (manufactured by Mac Science: DSC3110, thermal analysis system 001) according to ASTM D3418-8. It was determined by measuring from room temperature to 150 ° C. under a temperature rising rate of 10 ° C./min. The glass transition point was the temperature at the intersection of the extension line of the base line and the rising line in the endothermic part, and the melting point was the temperature at the apex of the endothermic peak.
Points (Tg) are indicated.

(Resin acid value)
The resin acid value (AV) was measured as follows. The basic operation conforms to JIS K-0070-1992.
The sample was used after removing the THF-insoluble component of the binder resin in advance, or the soluble component extracted with the THF solvent by the Soxhlet extractor obtained by the above-described measurement of the THF-insoluble component was used as the sample. 1.5 g of the pulverized sample was precisely weighed, and the sample was placed in a 300 ml beaker, and 100 ml of a toluene / ethanol (4/1) mixture was added and dissolved. Potentiometric titration was performed with an ethanol solution of 0.1 mol / l KOH using an automatic titrator GT-100 (manufactured by Dia Instruments). The amount of KOH solution used at this time is A (ml), and a blank is measured at the same time. The amount of KOH solution used at this time is B (ml). From these values, the acid value was calculated by the following formula (3). In formula (3), w is a precisely weighed sample amount and f is a factor of KOH.
Acid value (mgKOH / g) = {(A−B) × f × 5.61} / w (3)

  The amorphous resin particle dispersion used in the present invention is practically synthesized by an emulsion polymerization method. Therefore, it is necessary to remove the surfactant in the dispersion for measurement of the resin acid value. is there. The amorphous resin particle dispersion was placed in a semipermeable membrane, the surfactant was removed by dialysis, and the acid value was measured using this as an amorphous resin.

<Production of toner>
(Preparation of each dispersion)
-Crystalline resin particle dispersion (1)-
In a heat-dried three-necked flask, 98 mol% dimethyl sebacate, 2 mol% dimethyl-5-sulfonate sodium, 100 mol% 1,6-hexanediol, and dibutyltin oxide as a catalyst (0.014% based on acid component) ), The air in the container was brought into an inert atmosphere with nitrogen gas by depressurization, and the mixture was stirred and refluxed at 180 ° C. for 5 hours with mechanical stirring. Thereafter, the temperature was gradually raised to 230 ° C. under reduced pressure, and the mixture was stirred for 4 hours. When it became viscous, it was air-cooled, the reaction was stopped, and a crystalline polyester resin (1) was synthesized.

  The weight average molecular weight (Mw) of the obtained crystalline polyester resin (1) was 30000 by molecular weight measurement (polystyrene conversion) by gel permeation chromatography. Further, when the melting point (Tm) of the crystalline polyester resin (1) was measured using a differential scanning calorimeter (DSC) by the above-described measurement method, it showed a clear endothermic peak, and the endothermic peak temperature was 66 ° C. there were.

Subsequently, using the crystalline polyester resin (1), a resin particle dispersion was prepared as follows.
・ Crystalline polyester resin (1) 90 parts ・ Ionic surfactant (Neogen RK, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 1.8 parts ・ Ion-exchanged water 210 parts

  The above was heated to 100 ° C. and sufficiently dispersed with a homogenizer (manufactured by IKA, Ultra Tarrax T50), followed by dispersion treatment with a pressure discharge type gorin homogenizer for 1 hour, a volume average particle size of 130 nm, and a solid content of 30 % Crystalline resin particle dispersion (1) was obtained.

-Crystalline resin particle dispersion (2)-
In a heat-dried three-necked flask, 90.5 mol% of 1,10-dodecanedicarboxylic acid, 2 mol% of sodium dimethyl-5-sulfonate, 7.5 mol% of 5-tert-butylisophthalic acid, 100 mol of 1,9-nonanediol % And dibutyltin oxide (0.014% with respect to the acid component) as a catalyst, the air in the container was brought into an inert atmosphere with nitrogen gas by depressurization, and mechanical stirring was performed at 180 ° C. for 5 hours. Stirring and refluxing were performed. Thereafter, the temperature was gradually raised to 230 ° C. under reduced pressure, and the mixture was stirred for 4 hours. When it became viscous, it was cooled with air, the reaction was stopped, and a crystalline polyester resin (2) was synthesized.

  The weight average molecular weight (Mw) of the obtained crystalline polyester resin (2) was 28000 by molecular weight measurement (polystyrene conversion) by gel permeation chromatography. Further, when the melting point (Tm) of the crystalline polyester resin (2) was measured by the above-described measurement method using a differential scanning calorimeter (DSC), it showed a clear endothermic peak, and the endothermic peak temperature was 72 ° C. there were.

Next, a crystalline resin particle dispersion (2) was prepared using the crystalline polyester resin (2).
・ Crystalline polyester resin (2) 90 parts ・ Ionic surfactant (Neogen RK, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 1.8 parts ・ Ion-exchanged water 210 parts

  The above was heated to 100 ° C. and sufficiently dispersed with a homogenizer (manufactured by IKA, Ultra Turrax T50), followed by dispersion treatment with a pressure discharge type gorin homogenizer for 1 hour, a volume average particle size of 300 nm, and a solid content of 30 % Crystalline resin particle dispersion (2).

-Crystalline resin particle dispersion (3)-
A heat-dried three-necked flask was charged with 98 mol% dimethyl sebacate, 2 mol% dimethyl-5-sulfonate sodium, 100 mol% ethylene glycol, and dibutyltin oxide (0.014% with respect to the acid component) as a catalyst. After that, the air in the container was brought into an inert atmosphere with nitrogen gas by depressurization, and the mixture was stirred and refluxed at 180 ° C. for 5 hours with mechanical stirring. Thereafter, the temperature was gradually raised to 230 ° C. under reduced pressure, and the mixture was stirred for 4 hours. When it became viscous, it was cooled with air, the reaction was stopped, and a crystalline polyester resin (3) was synthesized.

  The weight average molecular weight (Mw) of the obtained crystalline polyester resin (3) was 9700 by molecular weight measurement (polystyrene conversion) by gel permeation chromatography. Further, when the melting point (Tm) of the crystalline polyester resin (3) was measured using a differential scanning calorimeter (DSC) by the above-described measurement method, it showed a clear endothermic peak, and the endothermic peak temperature was ℃. It was.

Subsequently, using the crystalline polyester resin (3), a resin particle dispersion was prepared as follows.
・ Crystalline polyester resin (3) 90 parts ・ Ionic surfactant (Neogen RK, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 1.8 parts ・ Ion-exchanged water 210 parts

The above was heated to 100 ° C. and sufficiently dispersed with a homogenizer (manufactured by IKA, Ultra Tarrax T50), followed by dispersion treatment with a pressure discharge type gorin homogenizer for 1 hour, a volume average particle size of 200 nm, and a solid content of 20 % Crystalline resin particle dispersion (3) was obtained.

-Amorphous resin particle dispersion (1-1)-
・ Styrene (made by Wako Pure Chemical Industries) 280 parts ・ n-butyl acrylate (made by Wako Pure Chemical Industries) 120 parts ・ β-carboxyethyl acrylate (manufactured by Rhodia Nikka) 18 parts

  A solution prepared by dissolving 1.5 parts of an anionic surfactant (Dowfax, manufactured by Dow Chemical Co., Ltd.) in 550 parts of ion-exchanged water is added to the mixture of the above components and dispersed and emulsified in a flask for 10 minutes. While slowly stirring and mixing, a solution prepared by dissolving 2.3 parts of ammonium persulfate in 50 parts of ion-exchanged water was added. Next, after sufficiently replacing the nitrogen in the flask, the solution in the flask is heated with an oil bath to 65 ° C. while stirring, and emulsion polymerization is continued for 5 hours, thereby anionic amorphous resin particles. Dispersion liquid (1-1) was obtained.

  The volume average particle diameter of the resin particles in the amorphous resin particle dispersion (1-1) is 173 nm, the solid content is 42.3%, the weight average molecular weight (Mw) is 456000, and the Z average molecular weight (Mz) is 958000. there were. Further, the ratio (Mw / AV) of Mw to resin acid value (AV) was 27200, and the glass transition temperature was 52.3 ° C.

-Amorphous resin particle dispersions (1-2) to (1-7)-
In the preparation of the amorphous resin particle dispersion (1-1), except that the amounts of ammonium persulfate (APS) and β-carboxyethyl acrylate (β-CEA) were changed as shown in Table 1, respectively, Amorphous resin particle dispersions (1-2) to (1-7) were prepared.
Table 1 shows the resin characteristics and dispersion characteristics of each dispersion.

-Amorphous resin particle dispersion (2-1)-
・ Styrene 72 parts ・ N-butyl acrylate 28 parts ・ Acrylic acid 2 parts ・ n-dodecyl mercaptan 0.05 parts

  In the above mixed solution, 0.3 part of a nonionic surfactant (Nonipol 400: manufactured by Sanyo Chemical Co., Ltd.) and 0.5 part of an anionic surfactant (Neogen SC: manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) are ionized. A solution dissolved in 250 parts of exchange water was added, dispersed and emulsified in a flask, and a solution in which 0.8 part of ammonium persulfate was dissolved in 10 parts of ion exchange water was added while slowly stirring and mixing for 10 minutes.

  Next, after sufficiently replacing the nitrogen in the system sufficiently, the flask was stirred and heated in an oil bath until the temperature in the system reached 70 ° C. while stirring, and emulsion polymerization was continued for 5 hours. Thereby, the volume average particle size is 220 nm, the solid content is 41.6%, the glass transition temperature is 52.6 ° C., the weight average molecular weight (Mw) is 360000, the Z average molecular weight (Mz) is 740000, Mw and the resin acid value ( An anionic amorphous resin particle dispersion (2-1) having an AV) ratio (Mw / AV) of 21400 was obtained.

-Amorphous resin dispersions (2-2) to (2-4)-
In the preparation of the amorphous resin particle dispersion (2-1), the amount of n-dodecyl mercaptan (n-DM) was changed as shown in Table 2 in the same manner. 2-2) to (2-4) were prepared.
Table 2 summarizes the resin characteristics and dispersion characteristics of each dispersion.

(Preparation of colorant dispersion)
-Colorant dispersion (1)-
・ Carbon black (Cabot, Regal 330) 30 parts ・ Anionic surfactant (Nippon Oil & Fats, Newlex R) 2 parts ・ Ion-exchanged water 220 parts

  The above components are mixed and pre-dispersed for 10 minutes with a homogenizer (Ultra Turrax, manufactured by IKA), and then subjected to dispersion treatment at a pressure of 245 mPa for 15 minutes using a counter impact type wet pulverizer (Altimizer, manufactured by Sugino Machine). A colorant dispersion (1) having a volume average particle size of 328 nm was obtained.

-Colorant dispersion (2)-
・ Copper phthalocyanine B15: 3 (manufactured by Dainichi Seika) 45 parts ・ Cationic surfactant (Neogen RK, Daiichi Kogyo Seiyaku) 5 parts ・ Ion-exchanged water 200 parts

  The above components are mixed and pre-dispersed for 10 minutes with a homogenizer (Ultra Turrax, manufactured by IKA), and then subjected to a dispersion treatment at a pressure of 245 mPa for 15 minutes using a counter impact wet pulverizer (Altimizer, manufactured by Sugino Machine). A colorant dispersion (2) having a volume average particle diameter of 385 nm was obtained.

(Preparation of release agent dispersion)
・ 45 parts of paraffin wax (HNP9, manufactured by Nippon Seiki Co., Ltd., melting point: 75 ° C.) 5 parts of cationic surfactant (Neogen RK, manufactured by Daiichi Kogyo Seiyaku) 200 parts of ion-exchanged water

  The components were mixed and heated to 80 ° C., pre-dispersed for 10 minutes with a homogenizer (Ultra Tarrax, manufactured by IKA), and then subjected to a dispersion treatment using a pressure-jet pulverizer (Gorin homogenizer, manufactured by Gorin). A release agent particle dispersion having a volume average particle diameter of 185 nm was obtained.

(Production of toner particles)
-Toner particles (1-1)-
-Crystalline resin particle dispersion (1) 80 parts-Amorphous resin particle dispersion (1-1) 180 parts-Colorant dispersion (1) 36 parts-Release agent dispersion 81 parts

  The above components were put into a round stainless steel flask to obtain a solution that was sufficiently mixed and dispersed with Ultra Turrax T50. Next, 0.2 parts of polyaluminum chloride was added to this solution to produce core agglomerated particles, and the dispersion operation was continued using an ultra turrax. Further, the solution in the flask was heated to 47 ° C. with stirring in an oil bath for heating, and maintained at 47 ° C. for 60 minutes, and then 42 parts of the amorphous resin particle dispersion (1-1) was gradually added thereto. Thus, core / shell aggregated particles were produced.

  Thereafter, a 0.5 mol / L sodium hydroxide aqueous solution was added to adjust the pH of the solution to 6.5, and then the stainless steel flask was sealed and heated to 98 ° C. while continuing to stir using a magnetic seal. A 3 mol / L nitric acid aqueous solution was added to adjust the pH of the solution to 4.2, and then a 0.3 mol / L citric acid aqueous solution was added to adjust the pH of the solution to 3.1, and the solution was held for 5 hours.

  After cooling, the particles dispersed in the solution were filtered, washed thoroughly with ion exchange water, and then subjected to solid-liquid separation by Nutsche suction filtration. This was further redispersed in 3 L of ion exchanged water at 40 ° C., and stirred and washed at 300 rpm for 15 minutes. This operation was further repeated 5 times, and when the pH of the filtrate was 7.01 and the electric conductivity was 15.8 μS / cm, No. was obtained by Nutsche suction filtration. Solid-liquid separation was performed using 5A filter paper, and the obtained solid was vacuum dried over 12 hours to obtain black toner particles (1-1).

When the particle size distribution of the toner particles (1-1) was measured, the volume average particle size D50v was 6.4 μm, the number average particle size distribution index GSDp was 1.25, and the volume average particle size distribution index GSDv was 1.28. It was. The shape factor SF1 of the toner particles (1-1) was 131.
The binder resin in the toner particles (1-1) was subjected to molecular weight measurement and acid value measurement by the above-described methods. As a result, Mw / AV was 22600 and Mz was 769000.

-Toner particles (1-2)-
In the production of the toner particles (1-1), toner particles (1) are similarly produced except that the amorphous resin particle dispersion (1-2) is used instead of the amorphous resin particle dispersion (1-1). -2).
The toner physical properties of the toner particles were evaluated in the same manner. The results are summarized in Table 3.

-Toner particles (1-3)-
Toner particles (1-1) were prepared in the same manner except that the amorphous resin particle dispersion (1-3) was used instead of the amorphous resin particle dispersion (1-1). -3) was produced.
The toner physical properties of the toner particles were evaluated in the same manner. The results are summarized in Table 3.

-Toner particles (1-4)-
In the production of the toner particles (1-1), the toner particles (1) were similarly prepared except that the amorphous resin particle dispersion (1-4) was used instead of the amorphous resin particle dispersion (1-1). -4) was produced.
The toner physical properties of the toner particles were evaluated in the same manner. The results are summarized in Table 3.

-Toner particles (1-5)-
Toner particles (1-5) were prepared in the same manner except that the crystalline resin particle dispersion (2) was used instead of the crystalline resin particle dispersion (1). .
The toner physical properties of the toner particles were evaluated in the same manner. The results are summarized in Table 3.

-Toner particles (1-6)-
Toner particles (1-6) were prepared in the same manner except that the colorant dispersion (2) was used instead of the colorant dispersion (1).
The toner physical properties of the toner particles were evaluated in the same manner. The results are summarized in Table 3.

-Toner particles (1-7)-
In preparation of the toner particles (1-1), the addition amount of the crystalline resin particle dispersion (1) is 65 parts, and the addition amount of the amorphous resin particle dispersion (1-1) is 193 parts. Similarly, toner particles (1-7) were produced.
The toner physical properties of the toner particles were evaluated in the same manner. The results are summarized in Table 3.

-Toner particles (1-8)-
In preparation of the toner particles (1-1), the addition amount of the crystalline resin particle dispersion (1) was 114 parts and the addition amount of the amorphous resin particle dispersion (1-1) was 148 parts. Similarly, toner particles (1-8) were produced.
The toner physical properties of the toner particles were evaluated in the same manner. The results are summarized in Table 3.

-Toner particles (1-9)-
In the production of the toner particles (1-1), toner particles (1) were similarly produced except that the amorphous resin particle dispersion (1-7) was used instead of the amorphous resin particle dispersion (1-1). -9) was produced.
The toner physical properties of the toner particles were evaluated in the same manner. The results are summarized in Table 3.

-Toner particles (1-10)-
In preparation of the toner particles (1-1), the addition amount of the crystalline resin particle dispersion (1) is 15 parts, and the addition amount of the amorphous resin particle dispersion (1-1) is 230 parts. Similarly, toner particles (1-10) were produced.
The toner physical properties of the toner particles were evaluated in the same manner. The results are summarized in Table 3.

-Toner particles (1-11)-
In preparation of the toner particles (1-1), the addition amount of the crystalline resin particle dispersion (1) was 175 parts, and the addition amount of the amorphous resin particle dispersion (1-1) was 140 parts. Similarly, toner particles (1-11) were produced.
The toner physical properties of the toner particles were evaluated in the same manner. The results are summarized in Table 3.

  The toner particles (1-1) were prepared in the same manner except that the amorphous resin particle dispersion (1-5) was used instead of the amorphous resin particle dispersion (1-1). Although an attempt was made to produce the toner particles, the viscosity during granulation was greatly increased, and toner particles that could withstand evaluation could not be obtained.

  Further, in the production of the toner particles (1-1), the production of the toner is similarly performed except that the amorphous resin particle dispersion (1-7) is used instead of the amorphous resin particle dispersion (1-1). However, it was difficult to control the shape during coalescence, and toner particles that could withstand evaluation could not be obtained.

-Toner particles (2-1)-
Amorphous resin tree dispersion (2-1) 270.6 parts Crystalline resin dispersion (3) 55.4 parts Colorant dispersion (2) 33.4 parts Release agent dispersion 153. 8 copies

  The above was put into a round stainless steel flask, and thoroughly mixed and dispersed with an Ultra Turrax T50. Next, 0.20 part of polyaluminum chloride was added thereto to produce core agglomerated particles, and the dispersion operation was continued with an ultra turrax. The flask was heated to 48 ° C. with stirring in an oil bath for heating. After maintaining at 48 ° C. for 60 minutes, 70.0 parts of the amorphous resin particle dispersion (2-2) was gradually added thereto to produce core / shell aggregated particles.

  Thereafter, the pH in the system was adjusted to 9.0 with a 0.5 mol / L sodium hydroxide aqueous solution, and then the stainless steel flask was sealed and heated to 96 ° C. while continuing to stir using a magnetic seal for 5 hours. Retained.

After completion of the reaction, the mixture was cooled, filtered, sufficiently washed with ion exchange water, and then subjected to solid-liquid separation by Nutsche suction filtration. This was further redispersed in 1 L of ion exchange water at 40 ° C., and stirred and washed at 300 rpm for 15 minutes. This operation was further repeated 5 times, and when the pH of the filtrate became 7.5 and the electric conductivity became 7.0 μS / cm, No. was obtained by Nutsche suction filtration. Solid-liquid separation was performed using 5A filter paper, and the obtained solid was vacuum-dried over 12 hours to obtain toner particles (2-1).
With respect to the toner particles (2-1), the toner physical properties were evaluated in the same manner as in Example 1. The results are summarized in Table 4.

-Toner particles (2-2)-
Noncrystalline resin resin dispersion (2-1) 272.7 parts Crystalline resin dispersion (3) 89.8 parts Colorant dispersion (2) 33.4 parts Release agent dispersion 115. 3 parts

  Toner particles (2-2) were produced in the same manner except that the formulation in the production of toner particles (2-1) was changed as described above. The toner physical properties of the toner particles were evaluated in the same manner. The results are summarized in Table 4.

-Toner particles (2-3)-
Amorphous resin tree dispersion (2-1) 193 parts Crystalline resin dispersion (3) 21.8 parts Colorant dispersion (2) 33.4 parts Release agent dispersion 307.5 parts

  Toner particles (2-3) were produced in the same manner except that the formulation in the production of toner particles (2-1) was changed as described above. The toner physical properties were evaluated in the same manner as for the toner particles. The results are summarized in Table 4.

-Toner particles (2-4)-
Amorphous resin resin dispersion (2-1) 250.3 parts Crystalline resin dispersion (3) 160.9 parts Colorant dispersion (2) 33.4 parts Release agent dispersion 76. 9 copies

  Toner particles (2-4) were produced in the same manner except that the formulation in the production of toner particles (2-1) was changed as described above. The toner physical properties were evaluated in the same manner as for the toner particles. The results are summarized in Table 4.

-Toner particles (2-5)-
Amorphous resin resin dispersion (2-1) 314.6 parts Crystalline resin dispersion (3) 64.4 parts Colorant dispersion (2) 33.4 parts Release agent dispersion 76. 9 copies

  Toner particles (2-5) were prepared in the same manner as in the preparation of toner particles (2-1) except that the formulation was changed as described above. The toner physical properties of the toner particles were evaluated in the same manner. The results are summarized in Table 4.

-Toner particles (2-6)-
-Amorphous resin resin dispersion (2-1) 137 parts-Crystalline resin dispersion (3) 105.6 parts-Colorant dispersion (2) 33.4 parts-Release agent dispersion 307.5 parts

  Toner particles (2-6) were prepared in the same manner as in the preparation of toner particles (2-1) except that the formulation was changed as described above. The toner physical properties of the toner particles were evaluated in the same manner. The results are summarized in Table 4.

-Toner particles (2-7)-
Amorphous resin resin dispersion (2-1) 207.5 parts Colorant dispersion (2) 33.4 parts Release agent dispersion 307.5 parts

  Toner particles (2-7) were produced in the same manner as in the production of toner particles (2-1) except that the formulation was changed as described above. The toner physical properties of the toner particles were evaluated in the same manner. The results are summarized in Table 4.

-Toner particles (2-8)-
-Amorphous resin resin dispersion (2-1) 357.5 parts-Colorant dispersion (2) 33.4 parts-Release agent dispersion 76.9 parts

  Toner particles (2-8) were produced in the same manner as in the production of toner particles (2-1) except that the formulation was changed as described above. The toner physical properties of the toner particles were evaluated in the same manner. The results are summarized in Table 4.

-Toner particles (2-9)-
Amorphous resin resin dispersion (2-1) 289.3 parts Crystalline resin dispersion (3) 177.3 parts Colorant dispersion (2) 33.4 parts

  Toner particles (2-9) were produced in the same manner as in the production of toner particles (2-1) except that the formulation was changed as described above. The toner physical properties of the toner particles were evaluated in the same manner. The results are summarized in Table 4.

-Toner particles (2-10)-
Amorphous resin resin dispersion (2-1) 271.6 parts Crystalline resin dispersion (3) 166.4 parts Colorant dispersion (2) 33.4 parts Release agent dispersion 38. 4 copies

  Toner particles (2-10) were produced in the same manner as in the production of toner particles (2-1) except that the formulation was changed as described above. The toner physical properties of the toner particles were evaluated in the same manner. The results are summarized in Table 4.

-Toner particles (2-11)-
Amorphous resin resin dispersion (2-1) 359.6 parts Crystalline resin dispersion (3) 34.4 parts Colorant dispersion (2) 33.4 parts Release agent dispersion 38. 4 copies

  Toner particles (2-11) were prepared in the same manner as in the preparation of toner particles (2-1) except that the formulation was changed as described above. The toner physical properties of the toner particles were evaluated in the same manner. The results are summarized in Table 4.

(Preparation of developer)
To 50 parts of the above toner particles, 3.5 parts of hydrophobic silica (TS720, manufactured by Cabot) was added as an external additive, and blended in a sample mill to obtain each externally treated toner.
On the other hand, 11 parts of toluene, 2 parts of diethylaminoethyl methacrylate-styrene-methyl methacrylate copolymer (copolymerization ratio: 2/20/78, weight average molecular weight 50,000), carbon black (manufactured by Cabot, R330R) 0.2 Parts and glass beads (particle size 1 mm, equivalent to toluene) were put into a sand mill manufactured by Kansai Paint Co., Ltd., and stirred at a rotational speed of 1200 rpm for 30 minutes to prepare a coating resin layer forming solution.

Next, 100 parts of this coating resin layer forming solution and Mn—Mg ferrite particles (true specific gravity: 4.6 g / cm ³ , volume average particle size: 35 μm, saturation magnetization: 65 emu / g) were vacuum degassed kneader. The mixture was stirred for 10 minutes while maintaining the temperature at 60 ° C., and then the pressure was reduced and toluene was distilled off to obtain a ferrite carrier having a coating resin layer formed thereon.
To this ferrite carrier, the toner is mixed so that the toner concentration becomes 5%, and stirred and mixed for 5 minutes by a ball mill, and the toner particles (1-1) to (1-11), (2-1) Developers (1-1) to (1-11) and (2-1) to (2-11) each containing-(2-11) were prepared.

<Example 1>
Using the developer (1-1) above, as an image forming apparatus, a fixing roll of DocuCenterColor500 (manufactured by Fuji Xerox Co., Ltd.), a metal roll made of SUS304 not coated with resin (arithmetic average roughness Ra: 1.0 μm) The toner image adjusted to a toner loading of 4.5 g / m ² was fixed at a process speed of 220 mm / sec and a fixing roll temperature of 170 ° C. In the image formation, J paper (Fuji Xerox Co., Ltd.) was used as paper.

Image formation was performed under the above conditions, and the following items were evaluated.
-Evaluation of image peelability-
The peelability between the paper and the metal roll during fixing was evaluated according to the following criteria.
(Double-circle): The level which has especially favorable peelability.
○: Level at which there is no problem in practical use with smooth peeling during fixing.
(Triangle | delta): The level which does not have a problem and can peel using a peeling nail | claw.
X: Level at which the peeling at the time of fixing is insufficient, causing a problem in practical use. Means.

-Evaluation of fixability-
Image fixability was evaluated according to the following criteria.
○: When the image is lightly rubbed with a nail, the image does not have a defect, and there is no practical problem.
(Triangle | delta): The level which a slight crack is attached when an image is lightly rubbed with a nail, and it has not reached the image defect.
×: Level at which defects occur in the image when the image is lightly rubbed with a nail, causing a problem in practice.

-Evaluation of glossiness-
The glossiness of the image is evaluated by using the gloss meter (micro-TRI-gloss, manufactured by BYK-Gardner) for the 3 cm × 4 cm image patch fixed as described above. Measured and judged according to the following criteria.
○: Glossiness is 60% or more.
Δ: Glossiness is 30% or more and less than 60%.
X: Glossiness is less than 30%.

-Evaluation of image maintenance-
Solid images and line images are divided and formed on the surfaces of the two sheets, and the image forming surfaces of the sheets are overlapped so that the following image overlapping pattern is obtained. from applying a load of 100 g / cm ^2, the defect state of the image after storage for 1 week were evaluated on the following criteria.
Overlay pattern 1) Solid image x Solid image 2) Solid image x Line image 3) Line image x Line image 4) Solid image x Blank paper part 5) Line image x Blank paper part

G5: There is no adhesion or loss between images (○)
G4: There is adhesion between images, but there is no image defect (◯)
G3: A defect is seen in a part of the line image (Δ)
G2: There is a remarkable defect especially in the solid image (×)
G1: Significant defects are seen in both solid and line images (×)
The above-mentioned actual machine evaluation results are summarized in Table 5.

<Examples 2-8, Comparative Examples 1-3>
In place of the developer (1-1) in Example 1, developers (1-2) to (1-11) as shown in Table 4 were used, and the same evaluation as in Example 1 was performed.
The results are summarized in Table 5.

<Examples 9 to 20 and Comparative Examples 4 to 10 >
Instead of developer (1-1) in Example 1, developers (2-1) to (2-11) as shown in Table 6 are used, and metal rolls are made of materials as shown in Table 6 respectively. The actual machine was evaluated in the same manner as in Example 1 except that the surface roughness was used.
The results are summarized in Table 6.

  As shown in the results of Tables 5 and 6, when the developer containing the toner of the present invention of the example was used, it was excellent in releasability at the time of fixing to a metal roll, and was long-term against heat and load. It can be seen that a stable image can be formed. On the other hand, with the developer used in the comparative example, some problem occurred in any of releasability from the metal roll, image gloss, and image maintainability.

<Example 21 >
In the modified DocuCenterColor500 used in each of the examples and comparative examples, the fixing unit is further removed so that unfixed images can be continuously printed, and the cleaning unit can supply a solid lubricant as shown in FIG. Modified to replace with a brush (brush roll).

The brush roll made of polypropylene, having a bristle length of 3 mm, a single fiber thickness of 0.7 denier, and a fiber density of 5.0 × 10 ³ / cm ² (32.3 × 10 ³ / inch ² ) Was brought into contact with the photosensitive member with a biting amount of 1.1 mm.

  The blade was set using urethane rubber so that the blade linear pressure was 3.0 gf / mm and the blade cleaning angle was 13.5 ° (blade hardness: 87, free length: 9 mm, set angle: 25 °). The photoconductor used was the original DocuCenterColor500, and as the developer, the developer (1-1) was put into the developing unit.

  Using the manufactured image forming apparatus, the peripheral speed of the photoconductor was adjusted to 220 mm / sec, the peripheral speed of the cleaning brush was adjusted to 250 mm / sec in the direction opposite to the photoconductor (Against), and a running test of 500,000 sheets was performed. . Thereafter, carbon fibers (Toray Industries, Inc., Toray Middle Fiber MLD-300) were mixed in each toner cartridge at a mass ratio of 1000 (toner): 1 with the toner, and the image density (A3 size overall image density ( Sampling of 50%, 30%, and 0% (blank paper) as the density at which pinhole leak phenomenon can be confirmed), and a portion corresponding to the area of one rotation of the photosensitive drum using all the obtained samples The pinhole leak defects that appeared in

  In the above-described continuous image output, the image density is changed in the drum axis direction in order to see the contribution due to the difference in image structure (toner density). FIG. 6 shows an image pattern used for image output. A white paper portion pattern was prepared with a high image density of 70% for each color and a medium image density of 10% for each color. Before and after the test, the film thickness of the photoreceptor was measured with an eddy current film thickness meter (Fischer Scope MMS manufactured by Fischer Instrument Co., Ltd.), and the difference (amount of wear) was obtained.

Usually, if the photoconductor wear amount is up to a residual film thickness of 10 μm, image quality defects do not occur, but if it exceeds this, fogging or the like tends to occur. However, when the in-plane wear unevenness (difference between the maximum wear amount and the minimum wear amount) is 4 μm or more, an image quality defect such as in-plane unevenness occurs.
Image defects due to pinhole leak and wear were judged according to the following criteria.

-Pinhole leak-
○: No sample was generated.
Δ: Slightly apparent at 50% image density, OK at 30% image density.
X: Visible at both 50% and 30% image density.

-Malfunction due to wear-
○: No image quality defect after endurance.
Δ: Density unevenness occurred at both 50% and 30% image density, and no blank paper sample was fogged.
X: Fog occurs in white paper print.
Table 7 shows the evaluation results.

<Example 22 >
In Example 21 , the evaluation was performed in the same manner except that the cleaning unit of the image forming apparatus was the original DocuCenterColor500.
The results are shown in Table 7.

  As shown in Table 7, even when a toner having a hard surface according to the present invention is used, it is understood that pinhole leakage and image defects can be prevented by performing image printing while supplying a solid lubricant.

1 is a schematic diagram illustrating an example of an image forming apparatus for carrying out an image forming method of the present invention. It is a schematic sectional drawing which illustrates the structure of the cleaning apparatus which can be used for this invention. It is the schematic which shows the contact state of a solid lubricant and a cleaning brush. It is a schematic sectional drawing of an example of the photoreceptor which can be used for a photoreceptor. It is a schematic sectional drawing of an example of a common photoreceptor. It is a schematic diagram which shows the image pattern used for the image output test.

Explanation of symbols

2 Rotating brush (cleaning brush)
3 Cleaning Blade 4 Solid Lubricant 5 Toner Conveying Auger 6 Regulating Member 50 Conductive Substrate 60 Undercoat Layer 71 Charge Generation Layer 72 Charge Transport Layer 110 Photoconductor (Image Carrier)
120 Charging device 130 Exposure device 140 Developing device 150 Cleaning device 210 Medium transfer belt 220, 230 Transfer device 250 Fixing device

Claims (6)

An electrostatic latent image developing toner containing at least a binder resin and a colorant,
The binder resin includes a styrene / acrylic resin that is an amorphous resin and a polyester resin that is a crystalline resin, and the content of the polyester resin in the binder resin is in the range of 10 to 30% by mass, The ratio (Mw / AV) of the weight average molecular weight (Mw) and the acid value (AV) of the binder resin is in the range of 20000 to 35000, and the Z average molecular weight (Mz) is in the range of 500,000 to 1600000. Ri, and a shell containing a core and said styrene-acrylic-based resin containing the styrene-acrylic resin and the polyester resin, the weight average molecular weight of the styrene-acrylic resin (Mw) is Ru der 300000-600000 A toner for developing an electrostatic latent image. At least, a crystalline resin particle dispersion obtained by dispersing polyester resin particles, which are crystalline resins having a volume average particle size of 1 μm or less, and styrene / acrylic resin particles, which are first amorphous resins , are dispersed. The first amorphous resin particle dispersion and the colorant dispersion obtained by dispersing the colorant are mixed to form core aggregated particles, and the second amorphous is added to the dispersion obtained by dispersing the aggregated particles. by mixing the second amorphous resin particle dispersion comprising the styrene-acrylic resin particles are rESIN dispersed, a styrene-acrylic resin particles are the second amorphous resin in the aggregated particles 2. The electrostatic latent image developing toner according to claim 1, wherein the adhered core / shell aggregated particles are formed, and the core / shell aggregated particles are heated to fuse and coalesce.   An electrostatic latent image developer comprising the electrostatic latent image developing toner according to claim 1. At least a charging step for charging the surface of the image carrier, an electrostatic latent image forming step for forming an electrostatic latent image according to image information on the charged surface of the image carrier, and a surface formed on the surface of the image carrier. A developing step of developing the electrostatic latent image with a developer containing toner to form a toner image, a step of transferring the toner image formed on the surface of the image carrier to the surface of the transfer member, and the surface of the recording member And a fixing step of fixing the toner image formed on the surface of the recording medium using a metal roll composed of at least one selected from metals, alloys and metal oxides as a fixing roll. In the method
An image forming method, wherein the toner is the electrostatic latent image developing toner according to claim 1.   The image forming method according to claim 4, wherein an arithmetic average roughness Ra of the surface of the fixing roll is in a range of 0.1 to 5 μm. After the step of transferring the toner image to the surface of the transfer target, further including the step of removing residual toner on the surface of the image carrier after transfer by a cleaning blade;
6. The image forming method according to claim 4, wherein a solid lubricant is supplied to the surface of the image carrier through a cleaning brush disposed upstream of the cleaning blade.

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