JP2009192602A - Electrophotographic developer - Google Patents

Abstract

[PROBLEMS] To improve offset resistance, use a developer for a long period of time, and even if a release agent is spent on the carrier in the developer, the chargeability of the carrier does not deteriorate, fogging and toner scattering occur. To provide a developer with a low content.
A toner including at least a release agent, a binder resin, a colorant, and an external additive and a carrier, and a frictional charging relationship between the toner and the carrier is (1) the relationship between the toner and the carrier. Triboelectric charge generated between the toner particles in a state before the external additive is attached to the toner and the carrier are oppositely charged, and (2) the toner and the toner The triboelectric charge generated between the carrier and the triboelectric charge generated between the carrier and the toner particles in a state in which the release agent is removed from the toner and before the external additive is attached are of the same polarity. A developer for electrophotography that is charged.
[Selection figure] None

Description

  The present invention relates to a developer used for image formation using an electrophotographic process.

  In the developing process, a developer used in electrophotography, electrostatic recording, electrostatic printing, and the like is once attached to an image carrier such as a photoreceptor on which an electrostatic charge image is formed, and then transferred to a transfer process. After being transferred from the photoconductor to a transfer medium such as transfer paper, the toner is fixed on the medium in a fixing step. At that time, as a developer for developing an electrostatic charge image formed on the latent image holding surface, a two-component developer composed of a carrier and a toner, or a one-component developer that does not require a carrier (magnetic toner, non-toner). Magnetic toner) is known. Conventionally, dry toners used for electrophotography, electrostatic recording, electrostatic printing, and the like are obtained by melt-kneading and finely pulverizing a toner binder (binder resin) such as styrene resin and polyester together with a colorant. It has been.

  These dry toners are developed and transferred onto paper or the like, and then fixed by heating and melting using a hot roll. At that time, if the hot roll temperature is too high, a problem (hot offset) in which the toner is excessively melted and fused to the hot roll occurs. On the other hand, if the heat roll temperature is too low, there is a problem that the toner does not melt sufficiently and fixing becomes insufficient. As energy savings and miniaturization of copiers and the like are being studied, toners with higher hot offset generation temperature (good hot offset resistance) and low fixing temperature (good low temperature fixability) are required. ing. In addition, the toner needs to have heat-resistant storage stability that does not block the toner during storage and at the atmospheric temperature in the apparatus. In particular, in full-color copying machines and full-color printers, the gloss and color mixing properties of the image are required, so the toner needs to have a lower melt viscosity, and a sharp-melt polyester toner binder is used. ing. However, since such toner easily causes hot offset, conventionally, in full-color devices, silicone oil or the like is applied to a heat roll. However, the method of applying silicone oil to the hot roll requires an oil tank and an oil application device, and the device is complicated and large. Moreover, it causes deterioration of the heat roll and requires maintenance every certain period.

  Therefore, a method of adding a release agent to the toner is generally used in order to prevent toner fusion without applying oil to the heat roll. The mold release agent is required to have high mold release properties in order to prevent hot offset. As the release agent, a wax having a melting point of about 50 to 150 ° C. is generally used. Since the release agent is softer than other toner constituents, if it is a two-component developer, the release agent selectively adheres to the carrier and the chargeability is significantly reduced. As a result, charging of the developer is lowered, and fogging, toner scattering, etc. occur, resulting in problems. Various proposals have been made so far, but no proposal has been made for a developer that improves the releasability of the toner and maintains the charge of the developer over a long period of time.

  Until now, many studies have been made to improve toner performance. In order to improve the low-temperature fixability and offset resistance of the toner, it is known that the toner contains a low softening point release agent (wax) such as polyolefin. For example, Patent Documents 1 to 3 propose toners containing a wax having a specific DSC endothermic peak. However, these toners need to further improve the low-temperature fixability and offset resistance, and also need to improve developability.

Patent Documents 4 to 7 propose using candelilla wax, higher fatty acid wax, higher alcohol wax, plant natural wax (carnauba, rice), montan ester wax, and the like as a release agent. ing. However, it is necessary to further improve the low-temperature fixability and hot offset resistance of the toner, and it is also necessary to improve the developability (chargeability) and durability of these toners. Generally, when such a low softening point release agent is contained in the toner, the fluidity of the toner is lowered, so that the developability and transferability are lowered. In addition, the chargeability, durability, and storage stability are likely to be adversely affected.

Patent Documents 8 to 13 propose that the toner contains two or more release agents in order to enlarge the fixing region (non-offset region). However, these toners still have a problem in uniformly dispersing the release agent into the toner particles.
Patent Document 14 proposes a toner containing a polyester resin and two types of offset inhibitors each having an acid value and a different softening point. However, this toner still has a problem in developability. In Patent Documents 15 and 16, the dispersion diameter of the wax inside the toner is specified. However, when the state and position of the wax in the toner are indefinite, sufficient releasability in fixing cannot be obtained. There is.

  Furthermore, Patent Document 17 proposes a toner in which a spherical wax is fixed on the surface of the toner. However, the wax existing on the surface of the toner reduces the fluidity of the toner, and therefore developability and transferability are reduced. To do. In addition, the chargeability, durability, and storage stability are likely to be adversely affected. Patent Document 18 proposes a toner in which wax is encapsulated in toner particles and localized near the surface of the toner particles. However, in terms of offset resistance, storage stability, and durability, all of them are proposed. It may be insufficient.

  In Patent Documents 19 and 20, in a pulverized toner using a styrene resin as a toner binder, a polyolefin release agent such as low molecular weight polyethylene and low molecular weight polypropylene, or a styrene resin is grafted to the polyolefin resin. Although it is disclosed that the resin is effective, the styrenic resin used here is inferior in low-temperature fixability, and thus has a problem for low-temperature fixing that satisfies the recent demand for energy saving.

JP-A-6-295093 JP-A-7-84401 Japanese Patent Laid-Open No. 9-258471 Japanese Patent Application Laid-Open No. 5-341579 JP-A-6-123999 JP-A-6-230600 JP-A-6-324514 JP 11-258934 A Japanese Patent Laid-Open No. 11-258935 JP-A-4-299357 JP-A-4-337737 JP-A-6-208244 JP-A-7-281478 JP-A-8-166686 JP-A-8-328293 JP-A-10-161335 JP 2001-305782 A JP 2001-26541 A Japanese Patent Publication No.52-3304 Japanese Patent Publication No. 7-82255

  An object of the present invention is to solve the conventional problems and achieve the following objects. That is, offset resistance is improved, and even when a developer is used over a long period of time and the release agent is spent on the carrier in the developer, the chargeability of the carrier does not decrease, and fogging and toner scattering occur. The object is to provide a low-quality developer.

[1] In an electrophotographic developer having a toner and a carrier containing at least a release agent, a binder resin, a colorant, and an external additive, the relationship between the toner and the carrier is determined by the following (1) and An electrophotographic developer characterized by satisfying the condition (2).
(1) The triboelectric charge generated between the toner and the carrier and the triboelectric charge generated between the toner particles before the external additive is attached to the toner and the carrier are oppositely charged. There is.
(2) Frictional charge generated between the toner and the carrier, and friction generated between the toner particles and the carrier in a state in which the release agent is removed from the toner and before the external additive is attached. Charge is the same polarity charge.
[2] The electrophotographic developer according to [1], wherein at least glycerin fatty acid ester or polyglycerin fatty acid ester is used as a release agent.
[3] The electrophotographic developer according to [2], wherein the hydroxyl value of the glycerin fatty acid ester or the polyglycerin fatty acid ester is 0 to 100 mgKOH / g.
[4] The electrophotography according to [2] or [3], wherein stearic acid or behenic acid, or both stearic acid and behenic acid are used as the fatty acid of glycerin fatty acid ester or polyglycerin fatty acid ester. Developer.
[5] The electrophotographic developer according to any one of [2] to [4], wherein the toner is a negatively chargeable toner.
[6] The developer for electrophotography according to any one of [1] to [5], wherein at least silica and titanium oxide are used as external additives.
[7] The electrophotographic developer according to any one of [1] to [6], wherein a release agent is contained in the toner in an amount of 1 to 10% by mass.
[8] The electrophotographic developer according to any one of [1] to [7], wherein at least a polyester resin is used as the binder resin.
[9] The electrophotographic developer according to any one of [1] to [8], wherein a yellow colorant is used as the colorant.
[10] The electrophotographic developer according to any one of [1] to [8], wherein a magenta colorant is used as the colorant.
[11] The electrophotographic developer according to any one of [1] to [8], wherein a cyan colorant is used as the colorant.
[12] The electrophotographic developer according to any one of [1] to [8], wherein a black colorant is used as the colorant.
[13] The electrophotographic latent image carrier according to any one of [1] to [12], wherein the electrostatic latent image carrier and the electrostatic latent image formed on the electrostatic latent image carrier can be mounted on the image forming apparatus. A process cartridge comprising at least developing means for developing with a developer to form a visible image.

  The developer of the present invention is excellent in offset resistance, and even if the release agent is spent on the carrier in the developer after being used for a long period of time, the chargeability of the carrier does not deteriorate, and fogging and toner scattering are prevented. Few.

Each raw material constituting the toner used in the present invention may be a known material as long as the properties of the toner satisfy the relationship defined in the present invention, and a combination thereof may be used.
In the toner of the present invention, the release agent is selected from materials that easily exhibit the opposite polarity to the toner, and other materials such as resin, external additive, charge control agent, and carrier charge are adjusted, and the addition amount is adjusted. It can be created by adjusting. In the two-component developer, the release agent is selectively spent on the carrier with respect to the other toner constituents due to long-term use. Since the release agent tends to exhibit a polarity opposite to that of the toner, the chargeability of the carrier with respect to the toner is difficult to decrease.

  In order to produce the toner of the present invention, it is necessary to reverse the chargeability of the toner base by incorporating a release agent in the toner. If a negatively chargeable toner is used, a release agent that tends to exhibit positive chargeability is used. If a positively chargeable toner is used, a developer that tends to exhibit negative chargeability is used. It becomes possible. Of course, it is necessary to adjust the chargeability of the external additive, the chargeability of the carrier, and the chargeability of the toner from which the external additive and the release agent are removed.

If the toner is negatively chargeable, a release agent that easily exhibits positive chargeability is used. In general, those that easily exhibit positive chargeability often include N atoms in the molecular structure. For this reason, it is possible to use an amide wax as a mold release agent.
For positively chargeable toners, a release agent that easily exhibits negative chargeability is used. In general, many of those that easily exhibit negative chargeability include those that contain F, Cl, Br, and atoms in the molecular structure, and those that contain a functional group such as COOH and CH ₃ . For this reason, it is conceivable to use fluorine wax, paraffin wax, polyethylene wax, or polypropylene wax as a release agent.

  In the present invention, it has been found that it is very effective to use a glycerin fatty acid ester or a polyglycerin fatty acid ester as a release agent for a negatively chargeable toner. Glycerin fatty acid ester or polyglycerol fatty acid ester is a material that is easily positively charged. The reason is unknown, but it is thought to be derived from the molecular skeleton. Moreover, glycerin fatty acid ester or polyglycerin fatty acid ester shows high performance as a mold release agent. In particular, it is effective for hot offset that occurs when the fixing portion becomes high temperature, and a toner exhibiting high hot offset property can be provided. Further, the glycerin fatty acid ester or the polyglycerin fatty acid ester is white or light yellow, and even when a color toner is used, the color turbidity does not occur.

  Glycerin fatty acid ester or polyglycerol fatty acid ester is obtained by esterifying glycerol or polyglycerol with a fatty acid. Further, in the present invention, the esterification is performed such that the hydroxyl group of glycerin or polyglycerin does not remain as much as possible, and the release effect is higher, and the chargeability of the glycerin fatty acid ester or the polyglycerin fatty acid ester tends to show a large positive charge. I found out. Specifically, the hydroxyl value of glycerol fatty acid ester or polyglycerol fatty acid ester is preferably 100 mgKOH / g or less, and more preferably 50 mgKOH / g or less. The hydroxyl value of glycerin fatty acid ester or polyglycerin fatty acid ester is measured according to JIS K-0070.

As the fatty acid, caproic acid, caprylic acid, pelargonic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, arachidic acid, behenic acid, isostearic acid and the like can be used. Even in the case of fatty acids, when the number of C atoms is small, the melting point of glycerin fatty acid ester or polyglycerin fatty acid ester becomes too low, and therefore fatty acid of lauric acid or higher is preferable. In addition, it is preferable to use a linear saturated fatty acid as compared with an unsaturated fatty acid or a branched fatty acid, because the glycerin fatty acid ester or the polyglycerin fatty acid ester becomes harder, and when used in toner, the spent on the carrier is suppressed. In view of the above and industrial and cost aspects, the fatty acid is most preferably stearic acid or behenic acid.
Polyglycerin is a glycerin polymer, and is obtained by a dehydration condensation reaction or the like.
The glycerin fatty acid ester or the polyglycerin fatty acid ester is obtained from plants as described above. For this reason, it is used for food additives and is very safe.

<Measurement method of charge amount>
The triboelectric charge generated between the sample powder particles (toner, toner without external additives or toner without external additives and release agent) and the carrier is measured by a TB203 powder charge amount measuring device manufactured by Kyocera Chemical Co., Ltd. Measure with. 1.0 g of sample powder particles and 19.0 g of the carrier are left in an environment of a temperature of 13 ± 3 degrees and a humidity of 58 ± 5 RH for 12 hours or more. After humidity control, put the toner carrier in a 50CC glass bottle, and mix for 3 minutes with the Turbula / Shaker / Mixer T2F type 5th speed (maximum speed). Weigh 0.5000 ± 0.0005g and set in the sample holder. Blowing is performed under the conditions of a suction pressure of 2 kPa / cm and a suction time of 10 s, and the charge amount is measured.

<Binder resin>
There is no restriction | limiting in particular as binder resin used for the toner of this invention, Usually used resin can be selected suitably and can be used. For example, vinyl polymers composed of styrene monomers, acrylic monomers, methacrylic monomers, copolymers of these monomers or two or more types, polyester polymers, polyol resins, phenols Examples thereof include resins, silicone resins, polyurethane resins, polyamide resins, furan resins, epoxy resins, xylene resins, terpene resins, coumarone indene resins, polycarbonate resins, and petroleum resins.
In the present invention, when a glycerin fatty acid ester or polyglycerin fatty acid ester is used as a release agent, a polyester resin is preferable. This is because the polyester resin tends to be negatively charged.

  Examples of the styrene monomer include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-phenylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, and pn-. Amyl styrene, p-tert-butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene, p-methoxy styrene , Styrene such as p-chlorostyrene, 3,4-dichlorostyrene, m-nitrostyrene, o-nitrostyrene, p-nitrostyrene, or derivatives thereof.

  Examples of the acrylic monomer include acrylic acid, methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate, n-octyl acrylate, n-dodecyl acrylate, and acrylic. Examples include 2-ethylhexyl acid, stearyl acrylate, 2-chloroethyl acrylate, acrylic acid such as phenyl acrylate, or esters thereof.

  Examples of the methacrylic monomer include methacrylic acid, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, n-dodecyl methacrylate, and methacrylic acid. And methacrylic acid or esters thereof such as 2-ethylhexyl, stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, and the like.

The following (1)-(18) is mentioned as an example of the other monomer which forms the said vinyl polymer or a copolymer.
(1) Monoolefins such as ethylene, propylene, butylene and isobutylene; (2) Polyenes such as butadiene and isoprene; (3) Vinyl halides such as vinyl chloride, vinylidene chloride, vinyl bromide and vinyl fluoride; (4) Vinyl esters such as vinyl acetate, vinyl propionate and vinyl benzoate; (5) Vinyl ethers such as vinyl methyl ether, vinyl ethyl ether and vinyl isobutyl ether; (6) Vinyl methyl ketone, vinyl hexyl ketone and methyl. Vinyl ketones such as isopropenyl ketone; (7) N-vinyl compounds such as N-vinyl pyrrole, N-vinyl carbazole, N-vinyl indole, N-vinyl pyrrolidone; (8), vinyl naphthalenes; (9) acrylonitrile, Such as methacrylonitrile, acrylamide, etc. (10) unsaturated dibasic acids such as maleic acid, citraconic acid, itaconic acid, alkenyl succinic acid, fumaric acid, mesaconic acid; (11) maleic anhydride, citraconic anhydride, Unsaturated dibasic acid anhydrides such as itaconic anhydride and alkenyl succinic anhydride; (12) maleic acid monomethyl ester, maleic acid monoethyl ester, maleic acid monobutyl ester, citraconic acid monomethyl ester, citraconic acid monoethyl ester Monoesters of unsaturated dibasic acids such as citraconic acid monobutyl ester, itaconic acid monomethyl ester, alkenyl succinic acid monomethyl ester, fumaric acid monomethyl ester, mesaconic acid monomethyl ester; (13) dimethylmaleic acid, dimethylfumaric acid, etc. (14) α, β-unsaturated acids such as crotonic acid and cinnamic acid; (15) α, β-unsaturated acid anhydrides such as crotonic acid anhydride and cinnamic anhydride; 16) Monomers having a carboxyl group such as anhydrides of the α, β-unsaturated acids and lower fatty acids, alkenylmalonic acid, alkenylglutaric acid, alkenyladipic acid, acid anhydrides and monoesters thereof; ) Acrylic acid or methacrylic acid hydroxyalkyl esters such as 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate; (18) 4- (1-hydroxy-1-methylbutyl) styrene, 4- (1 Monomers having a hydroxy group such as hydroxy-1-methylhexyl) styrene.

In the toner of the present invention, the vinyl polymer or copolymer of the binder resin may have a crosslinked structure crosslinked with a crosslinking agent having two or more vinyl groups. Examples of the crosslinking agent used in this case include aromatic vinyl vinyl compounds such as divinylbenzene and divinylnaphthalene. Examples of diacrylate compounds linked by an alkyl chain include ethylene glycol diacrylate, 1,3-butylene glycol diacrylate, 1,4-butanediol diacrylate, 1,5-pentanediol diacrylate, and 1,6. And xanthdiol diacrylate, neopentyl glycol diacrylate, and those obtained by replacing acrylates of these compounds with methacrylate. Examples of diacrylate compounds linked by an alkyl chain containing an ether bond include diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol # 400 diacrylate, polyethylene glycol # 600 diacrylate, and dipropylene. Examples include glycol diacrylate and those obtained by replacing acrylate of these compounds with methacrylate.
Other examples include diacrylate compounds and dimethacrylate compounds linked by a chain containing an aromatic group and an ether bond. Examples of polyester diacrylates include trade name MANDA (manufactured by Nippon Kayaku Co., Ltd.).

  Examples of the polyfunctional crosslinking agent include pentaerythritol triacrylate, trimethylol ethane triacrylate, trimethylol propane triacrylate, tetramethylol methane tetraacrylate, oligoester acrylate, and acrylates of the above compounds in place of methacrylate, triallyl cyanide. Examples include nurate and triallyl trimellitate.

  These cross-linking agents are preferably used in an amount of 0.01 to 10 parts by mass, and 0.03 to 5 parts by mass, with respect to 100 parts by mass of the other monomers forming the vinyl polymer or copolymer. More preferred. Among these crosslinkable monomers, diacrylates bonded to a toner resin from a bond chain containing an aromatic divinyl compound (particularly divinylbenzene), an aromatic group, and an ether bond from the viewpoint of fixability and offset resistance. Preferred examples include compounds. Among these, a combination of monomers that becomes a styrene copolymer or a styrene-acrylic copolymer is preferable.

  Examples of the polymerization initiator used in the production of the vinyl polymer or copolymer of the present invention include 2,2′-azobisisobutyronitrile, 2,2′-azobis (4-methoxy-2,4- Dimethylvaleronitrile), 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobis (2-methylbutyronitrile), dimethyl-2,2′-azobisisobutyrate, 1 , 1′-azobis (1-cyclohexanecarbonitrile), 2- (carbamoylazo) -isobutyronitrile, 2,2′-azobis (2,4,4-trimethylpentane), 2-phenylazo-2 ′ , 4′-dimethyl-4′-methoxyvaleronitrile, 2,2′-azobis (2-methylpropane), methyl ethyl ketone peroxide, acetylacetone peroxide, Ketone peroxides such as rohexanone peroxide, 2,2-bis (tert-butylperoxy) butane, tert-butyl hydroperoxide, cumene hydroperoxide, 1,1,3,3-tetramethylbutyl Hydroperoxide, di-tert-butyl peroxide, tert-butylcumyl peroxide, dicumyl peroxide, α- (tert-butylperoxy) isopropylbenzene, isobutyl peroxide, octanoyl peroxide, decanoyl peroxide , Lauroyl peroxide, 3,5,5-trimethylhexanoyl peroxide, benzoyl peroxide, m-tolyl peroxide, di-isopropylperoxydicarbonate, di-2-ethylhexylpero Xidicarbonate, di-n-propyl peroxydicarbonate, di-2-ethoxyethyl peroxycarbonate, di-ethoxyisopropyl peroxydicarbonate, di (3-methyl-3-methoxybutyl) peroxycarbonate, acetylcyclo Hexylsulfonyl peroxide, tert-butyl peroxyacetate, tert-butyl peroxyisobutyrate, tert-butyl peroxy-2-ethylhexarate, tert-butyl peroxylaurate, tert-butyl-oxybenzoate, tert-butylperoxyisopropyl carbonate, di-tert-butylperoxyisophthalate, tert-butylperoxyallyl carbonate, isoamylperoxy-2-ethylhexanoate, di- tert- butylperoxy to hexa hydro terephthalate, tert- butylperoxy azelate, and the like.

  In the case where the binder resin is a styrene-acrylic resin, the molecular weight distribution by GPC soluble in the resin component tetrahydrofuran (THF) is at least one in the region of molecular weight 3,000 to 50,000 (in terms of number average molecular weight). A resin having a peak and having at least one peak in a region having a molecular weight of 100,000 or more is preferable in terms of fixing property, offset property, and storage property. Further, as the THF soluble component, a binder resin in which a component having a molecular weight distribution of 100,000 or less is 50 to 90% is preferable, and a binder resin having a main peak in a region having a molecular weight of 5,000 to 30,000. Is more preferable, and a binder resin having a main peak in the region of 5,000 to 20,000 is most preferable.

  The acid value when the binder resin is a vinyl polymer such as styrene-acrylic resin is preferably 0.1 mgKOH / g to 100 mgKOH / g, and preferably 0.1 mgKOH / g to 70 mgKOH / g. More preferably, it is most preferably 0.1 mgKOH / g to 50 mgKOH / g.

The following are mentioned as a monomer which comprises a polyester-type polymer.
Examples of the divalent alcohol component include ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, diethylene glycol, triethylene glycol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, 2-ethyl-1,3-hexanediol, hydrogenated bisphenol A, or diol obtained by polymerizing cyclic ethers such as ethylene oxide and propylene oxide to bisphenol A, etc. Is mentioned.

In order to crosslink the polyester resin, it is preferable to use a trivalent or higher alcohol together.
Examples of the trihydric or higher polyhydric alcohol include sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, such as dipentaerythritol, tripentaerythritol, 1,2,4- Butanetriol, 1,2,5-pentatriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-trihydroxybenzene , Etc.

  Examples of the acid component that forms the polyester polymer include benzene dicarboxylic acids such as phthalic acid, isophthalic acid, and terephthalic acid or anhydrides thereof, alkyldicarboxylic acids such as succinic acid, adipic acid, sebacic acid, and azelaic acid, or Unsaturated dibasic acids such as anhydride, maleic acid, citraconic acid, itaconic acid, alkenyl succinic acid, fumaric acid, mesaconic acid, maleic anhydride, citraconic anhydride, itaconic anhydride, alkenyl succinic anhydride And unsaturated dibasic acid anhydrides. Examples of the trivalent or higher polyvalent carboxylic acid component include trimet acid, pyromet acid, 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxy-2-methyl-2-methylenecarboxypropane, tetra (methylene Carboxy) methane, 1,2,7,8-octanetetracarboxylic acid, empol trimer acid, or anhydrides thereof, partial lower alkyl esters, and the like.

  When the binder resin is a polyester resin, at least one peak is present in the molecular weight region of 3,000 to 50,000 in the molecular weight distribution by GPC measurement of the THF soluble component of the resin component. It is preferable in terms of offset resistance, and as a THF soluble component, a binder resin in which a component having a molecular weight of 100,000 or less is 60 to 100% is also preferable, and at least one in a region having a molecular weight of 5,000 to 20,000. A binder resin having a peak is more preferable.

When the binder resin is a polyester resin, the acid value is preferably 0.1 mgKOH / g to 100 mgKOH / g, more preferably 0.1 mgKOH / g to 70 mgKOH / g, and 0.1 mgKOH / g. Most preferably, it is g-50 mgKOH / g.
Moreover, the chargeability of the polyester resin can be adjusted by adjusting the acid value. Generally, when the acid value is increased, the negative chargeability is increased.
In the present invention, the molecular weight distribution of the binder resin is measured by gel permeation chromatography (GPC) using THF as a solvent.

  As the binder resin that can be used in the toner of the present invention, a resin containing a monomer component capable of reacting with both of these resin components in at least one of the vinyl polymer component and the polyester resin component can also be used. . Examples of monomers that can react with the vinyl polymer among the monomers constituting the polyester resin component include unsaturated dicarboxylic acids such as phthalic acid, maleic acid, citraconic acid, and itaconic acid, or anhydrides thereof. Examples of the monomer constituting the vinyl polymer component include those having a carboxyl group or a hydroxy group, and acrylic acid or methacrylic acid esters.

Moreover, when using together a polyester polymer, a vinyl polymer, and another binder resin, what has 60 mass% or more of resin whose acid value of the whole binder resin has 0.1-50 mgKOH / g is preferable.
In the present invention, the acid value of the binder resin component of the toner composition is measured according to JIS K-0070.

  The toner binder resin and the composition containing the binder resin preferably have a glass transition temperature (Tg) of 55 to 70 ° C., more preferably 57 to 70 ° C., from the viewpoint of toner storage stability. When Tg is lower than 55 ° C., the toner is likely to deteriorate in a high temperature atmosphere, and offset may easily occur during fixing. On the other hand, when Tg exceeds 70 ° C., fixability may be deteriorated.

In the present invention, a polyester resin having crystallinity may be used to promote low-temperature fixing. The polyester resin is characterized by comprising a crystalline aliphatic polyester resin containing at least 60 mol% of an ester bond represented by the following general formula (1) in its molecular main chain.

（前記一般式（１）中、Ｒは直鎖状不飽和脂肪族２価カルボン酸残基を示し、炭素数２〜２０、好ましくは２〜４の直鎖状不飽和脂肪族基である。ｎは２〜２０、好ましくは２〜６の整数である。）

(In the general formula (1), R represents a linear unsaturated aliphatic divalent carboxylic acid residue, and is a linear unsaturated aliphatic group having 2 to 20 carbon atoms, preferably 2 to 4 carbon atoms. n is an integer of 2 to 20, preferably 2 to 6.)

The presence of the structure of the general formula (1) can be confirmed by solid C ¹³ NMR.
Specific examples of the linear unsaturated aliphatic group include linear unsaturated divalent carboxylic acids such as maleic acid, fumaric acid, 1,3-n-propene dicarboxylic acid, and 1,4-n-butene dicarboxylic acid. Mention may be made of linear unsaturated aliphatic groups derived from acids.

In the general formula (1), (CH ₂ ) n represents a linear aliphatic dihydric alcohol residue. Specific examples of the linear aliphatic dihydric alcohol residue in this case include linear aliphatic 2 such as ethylene glycol, 1,3-propylene glycol, 1,4-butanediol, and 1,6-hexanediol. Those derived from dihydric alcohols can be indicated. Since the polyester resin (A) uses a linear unsaturated aliphatic dicarboxylic acid as its acid component, the polyester resin (A) exhibits an effect that a crystal structure is easily formed as compared with the case where an aromatic dicarboxylic acid is used.

  The crystalline polyester resin is a polyvalent carboxylic acid comprising (i) a linear unsaturated aliphatic divalent carboxylic acid or a reactive derivative thereof (an acid anhydride, a lower alkyl ester having 1 to 4 carbon atoms, an acid halide, etc.). It can be produced by subjecting an acid component and a polyhydric alcohol component comprising (ii) a linear aliphatic diol to a polycondensation reaction by a conventional method. In this case, a small amount of other polyvalent carboxylic acid can be added to the polyvalent carboxylic acid component as necessary. In this case, the polyvalent carboxylic acid includes (i) an unsaturated aliphatic divalent carboxylic acid having a branched chain, (ii) a saturated aliphatic divalent carboxylic acid, a saturated aliphatic trivalent carboxylic acid, and the like. In addition to polyvalent carboxylic acids, (iii) aromatic polyvalent carboxylic acids such as aromatic divalent carboxylic acids and aromatic trivalent carboxylic acids are included. The addition amount of these polyvalent carboxylic acids is usually 30 mol% or less, preferably 10 mol% or less, based on the total carboxylic acid, and is appropriately added within the range where the resulting polyester has crystallinity.

  Specific examples of polyvalent carboxylic acids that can be added as needed include malonic acid, succinic acid, glutaric acid, adipic acid, suberic acid, sebacic acid, citraconic acid, phthalic acid, isophthalic acid, terephthalic acid, etc. A divalent carboxylic acid of: trimetic anhydride, 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 1,2,4-cyclohexanetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, And trivalent or higher polyvalent carboxylic acids such as 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methylenecarboxypropane, 1,2,7,8-octanetetracarboxylic acid, etc. it can.

  A trivalent or higher polyhydric alcohol can be added to the polyhydric alcohol component, if necessary, in addition to a small amount of an aliphatic branched dihydric alcohol or cyclic dihydric alcohol. The addition amount is 30 mol% or less, preferably 10 mol% or less, based on the total alcohol, and is appropriately added within the range in which the resulting polyester has crystallinity. Examples of polyhydric alcohol added as needed include 1,4-bis (hydroxymethyl) cyclohexane, polyethylene glycol, bisphenol A ethylene oxide adduct, bisphenol A propylene oxide adduct, glycerin and the like.

  In the crystalline polyester resin, the molecular weight distribution is preferably sharp from the viewpoint of low-temperature fixability, and the molecular weight is preferably a relatively low molecular weight. As for the molecular weight of the crystalline polyester resin, the weight average molecular weight (Mw) thereof is 5500-6500, the number average molecular weight (Mn) thereof is 1300-1500 and its molecular weight distribution by GPC of the o-dichlorobenzene soluble component. The Mw / Mn ratio is preferably 2-5.

  The molecular weight distribution of the crystalline polyester resin is based on a molecular weight distribution diagram in which the horizontal axis is logM (M is molecular weight) and the vertical axis is mass%. In the case of the polyester resin (A) used in the present invention, in this molecular weight distribution diagram, it is preferable to have a molecular weight peak in the range of 3.5 to 4.0 (mass%), and the half width of the peak is 1. 5 or less is preferable.

In the crystalline polyester resin, the glass transition temperature (Tg) and the softening temperature [T (F _1/2 )] are desirably low as long as the heat-resistant storage stability of the toner is not deteriorated. Tg is 80 to 130 ° C., preferably 80 to 125 ° C., and T (F _1/2 ) is 80 to 130 ° C., preferably 80 to 125 ° C. When Tg and T (F _1/2 ) are higher than the above ranges, the lower limit fixing temperature of the toner is increased, so that the low temperature fixing property of the toner is deteriorated.

<Colorant>
As the colorant used in the present invention, all known dyes and pigments can be used. For example, carbon black, nigrosine dye, iron black, naphthol yellow S, Hansa yellow (10G, 5G, G), cadmium yellow, yellow iron oxide, ocher, yellow lead, titanium yellow, polyazo yellow, oil yellow, Hansa yellow ( GR, A, RN, R), Pigment Yellow L, Benzidine Yellow (G, GR), Permanent Yellow (NCG), Vulcan Fast Yellow (5G, R), Tartrazine Lake, Quinoline Yellow Lake, Anthrazan Yellow BGL, Iso Indolinone Yellow, Bengala, Pangdan, Lead Red, Cadmium Red, Cadmium Mercury Red, Antimony Zhu, Permanent Red 4R, Para Red, Faise Red, Parachlor Ortho Nitroaniline Red, Resol Fast Scarlet G, Brilli Fast Scarlet, Brilliant Carmine BS, Permanent Red (F2R, F4R, FRL, FRLL, F4RH), Fast Scarlet VD, Belkan Fast Rubin B, Brilliant Scarlet G, Resol Rubin GX, Permanent Red F5R, Brilliant Carmine 6B, Pogment Scarlet 3B, Bordeaux 5B, Toluidine Maroon, Permanent Bordeaux F2K, Helio Bordeaux BL, Bordeaux 10B, Bon Maroon Light, Bon Maroon Medium, Eosin Lake, Rhodamine Lake B, Rhodamine Lake Y, Alizarin Lake, Thioindigo Red B, Thioindigo Maroon , Oil red, quinacridone red, pyrazolone red, polyazo red, chrome vermilion, benzidine oren , Perinone orange, oil orange, cobalt blue, cerulean blue, alkaline blue rake, peacock blue rake, Victoria blue rake, metal-free phthalocyanine blue, phthalocyanine blue, fast sky blue, indanthrene blue (RS, BC), indigo, Ultramarine blue, bitumen, anthraquinone blue, fast violet B, methyl violet lake, cobalt purple, manganese purple, dioxane violet, anthraquinone violet, chrome green, zinc green, chromium oxide, pyridian, emerald green, pigment green B, naphthol green B, green Gold, Acid Green Lake, Malachite Green Lake, Phthalocyanine Green, Anthraquinone Green, Titanium Oxide, Zinc white, litbon and mixtures thereof can be used. The content of the colorant is preferably 1 to 15% by mass and more preferably 3 to 10% by mass with respect to the toner.

  The colorant used in the present invention can also be used as a master batch combined with a resin. As the binder resin to be kneaded with the master batch, the same resin as the binder resin can be used. Moreover, binder resin may be used individually by 1 type, and 2 or more types may be mixed and used for it.

The master batch can be obtained by mixing and kneading a resin for a master batch and a colorant under a high shear force. At this time, an organic solvent can be used to enhance the interaction between the colorant and the resin. Also, there is a method of removing the water and organic solvent components by mixing and kneading an aqueous paste containing water, which is a so-called flushing method, together with a resin and an organic solvent, and transferring the colorant to the resin side. Since the wet cake can be used as it is, it does not need to be dried and is preferably used. For mixing and kneading, a high shearing dispersion device such as a three-roll mill is preferably used.
As the usage-amount of the said masterbatch, 0.1-20 mass parts is preferable with respect to 100 mass parts of binder resin.

  The resin for the masterbatch preferably has an acid value of 30 mgKOH / g or less, an amine value of 1 to 100, and a colorant dispersed therein. The acid value is 20 mgKOH / g or less and the amine value is 10 It is more preferable that the colorant is dispersed and used at ˜50. When the acid value exceeds 30 mgKOH / g, the chargeability under high humidity may be lowered, and the pigment dispersibility may be insufficient. Also, when the amine value is less than 1 and when the amine value exceeds 100, the pigment dispersibility may be insufficient. The acid value can be measured by the method described in JIS K0070, and the amine value can be measured by the method described in JIS K7237.

  Further, a dispersant can be used in order to enhance the dispersibility of the pigment. The dispersant is preferably highly compatible with the binder resin in terms of pigment dispersibility. Specific examples of commercially available products include “Ajisper PB821”, “Azisper PB822” (manufactured by Ajinomoto Fine Techno Co., Ltd.), “ Disperbyk-2001 "(manufactured by Big Chemie)," EFKA-4010 "(manufactured by EFKA), and the like.

The mass average molecular weight of the dispersant is the maximum molecular weight of the main peak in terms of styrene in gel permeation chromatography, preferably 500 to 100,000, and from the viewpoint of pigment dispersibility, 3,000 to 100 1,000 is more preferable. In particular, 5,000 to 50,000 are preferable, and 5,000 to 30,000 are most preferable. When the molecular weight is less than 500, the polarity increases and the dispersibility of the colorant may decrease. When the molecular weight exceeds 100,000, the affinity with the solvent increases and the dispersibility of the colorant decreases. There are things to do.
The dispersant is preferably blended in the toner at a ratio of 0.1 to 10% by mass with respect to the colorant. When the blending ratio is less than 0.1% by mass, the pigment dispersibility may be insufficient, and when it is more than 10% by mass, the chargeability under high humidity may be deteriorated.

<Release agent>
Any known release agent in the toner of the present invention can be used. Furthermore, it is also possible to use glycerin fatty acid ester or polyglycerin fatty acid ester together with the following release agent.
As described above, all known release agents can be used, and examples thereof include carbonyl group-containing waxes, polyolefin waxes, long-chain hydrocarbons, amide waxes, and aliphatic carboxylates. These may be used individually by 1 type and may use 2 or more types together. The releasing agent is preferably contained in the toner in an amount of 1 to 10% by mass.

  Examples of the carbonyl group-containing wax include polyalkanoic acid esters, polyalkanol esters, polyalkanoic acid amides, polyalkylamides, dialkyl ketones, and the like. Examples of the polyalkanoic acid ester include carnauba wax, montan wax, trimethylolpropane tribehenate, pentaerythritol tetrabehenate, pentaerythritol diacetate dibehenate, glycerin tribehenate, 1,18-octadecane. Examples thereof include diol distearate. Examples of the polyalkanol ester include tristearyl trimellitic acid and distearyl maleate. Examples of the polyalkanoic acid amide include dibehenyl amide. Examples of the polyalkylamide include trimellitic acid tristearylamide. Examples of the dialkyl ketone include distearyl ketone. Of these carbonyl group-containing waxes, polyalkanoic acid esters are particularly preferred.

Examples of the polyolefin wax include polyethylene wax and polypropylene wax.
Examples of the long chain hydrocarbon include paraffin wax and sazol wax.

  Examples of the amide wax include lauric acid amide, palmitic acid amide, stearic acid amide, erucic acid amide, behenic acid amide, N-stearyl stearic acid amide, methylol stearic acid amide, methylol behenic acid amide, dimethylol oil amide, dimethyl Lauric acid amide, dimethyl stearic acid amide, ethylene bis oleic acid amide, ethylene bis stearic acid amide, methylene bis stearic acid amide, ethylene bis lauric acid amide, hexamethylene bis oleic acid amide, hexamethylene bis stearic acid amide, butylene bis stearic acid amide Acid amide, m-xylylene bis-stearic acid amide, m-xylylene bis-12 hydroxystearic acid amide, N, N′-dioleyl adipic acid amide, N, N′-distea Luadipic acid amide, N, N′-distearylisophthalic acid amide, N, N′-distearyl terephthalic acid amide, N-butyl-N′stearyl urea, N-propyl-N′stearyl urea, N-allyl-N ′ Examples include stearyl urea and N-stearyl-N′stearyl urea.

  Examples of the aliphatic carboxylate include sodium laurate, potassium laurate, potassium hydrogen laurate, magnesium laurate, calcium laurate, zinc laurate, silver laurate, lithium myristate, sodium myristate, potassium hydrogen myristate, Magnesium myristate, calcium myristate, zinc myristate, silver myristate, lithium palmitate, potassium palmitate, magnesium palmitate, calcium palmitate, zinc palmitate, copper palmitate, lead palmitate, thallium palmitate, palmitate Cobalt, sodium oleate, potassium oleate, magnesium oleate, calcium oleate, zinc oleate, lead oleate, thallium oleate, oleic acid , Nickel oleate, sodium stearate, lithium stearate, magnesium stearate, calcium stearate, barium stearate, aluminum stearate, thallium stearate, lead stearate, nickel stearate, bevelium stearate, sodium isostearate, isostearic acid Potassium, magnesium isostearate, calcium isostearate, barium isostearate, aluminum isostearate, zinc isostearate, nickel isostearate, sodium behenate, potassium behenate, magnesium behenate, calcium behenate, barium behenate, aluminum behenate, Zinc behenate, nickel behenate, sodium montanate, montan Potassium, magnesium montanate, calcium montanate, barium montanate, aluminum montanate, zinc montanate, montanic acid nickel, and the like.

<Charge control agent>
The toner of the present invention may contain a charge control agent as necessary. Any known charge control agent can be used. However, the color toner is preferably white or light color. In the case of a colored charge control agent, it is necessary to reduce the content because the color is mixed with the toner. Examples of charge control agents include nigrosine dyes, triphenylmethane dyes, chromium-containing metal complex dyes, molybdate chelate pigments, rhodamine dyes, alkoxy amines, quaternary ammonium salts (including fluorine-modified quaternary ammonium salts). ), Alkylamide, phosphorus alone or compound, tungsten alone or compound, fluorine-based activator, salicylic acid metal salt, and metal salt of salicylic acid derivative. Specifically, Nitronine-based dye Bontron 03, quaternary ammonium salt Bontron P-51, metal-containing azo dye Bontron S-34, oxynaphthoic acid metal complex E-82, salicylic acid metal complex E- 84, E-89 of a phenol-based condensate (manufactured by Orient Chemical Co., Ltd.), TP-302 of a quaternary ammonium salt molybdenum complex, TP 415 (manufactured by Hodogaya Chemical Co., Ltd.), quaternary ammonium Copy charge PSY VP2038 of salt, copy blue PR of triphenylmethane derivative, copy charge of quaternary ammonium salt NEG VP2036, copy charge NX VP434 (above, manufactured by Hoechst), LRA-901, LR-147 which is a boron complex (Nippon Carlit Co., Ltd.), copper phthalocyanine, perylene, quinacridone Azo pigments, sulfonate group, carboxyl group, and polymer compounds having a functional group such as a quaternary ammonium salt.

  In the present invention, the amount of charge control agent used is determined uniquely by the type of binder resin, the presence or absence of additives used as necessary, and the toner production method including the dispersion method, and is uniquely limited. However, it is preferably used in the range of 0.1 to 10 parts by mass with respect to 100 parts by mass of the binder resin. Preferably, the range of 0.2-5 mass parts is good. When the amount exceeds 10 parts by mass, the chargeability of the toner is too high, the effect of the main charge control agent is reduced, the electrostatic attraction with the developing roller is increased, the flowability of the developer is reduced, and the image density is reduced. Incurs a decline. These charge control agents and release agents can be melt-kneaded together with the master batch and resin.

<External additive>
In addition, in order to improve the fluidity, storage stability, developability, transferability, and durability of the toner, inorganic fine particles such as oxide fine particles and hydrophobic silica fine powder as an external additive to the toner base particles, and polymer type These resin fine particles may be added and mixed. This effect can be obtained by covering the wax that lowers transferability and durability with these external additives and reducing the contact area due to the toner surface being covered with fine particles. The surface of these inorganic fine particles is preferably subjected to a hydrophobic treatment, and metal oxide fine particles such as silica and titanium oxide subjected to the hydrophobic treatment are preferably used. Toner with improved toner transfer rate and good filming resistance by increasing the external addition amount of hydrophobized titanium oxide compared to the external addition amount of hydrophobized silica to improve charging stability against humidity It can be.

  The primary particle diameter of the inorganic fine particles or the resin fine particles is preferably 5 nm to 2 μm. Although the proportion of the inorganic fine particles used depends on the type, it is used in the range of 0.01 to 5% by mass with respect to the toner particles. Specific examples of the inorganic fine particles include, for example, silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, tin oxide, silica sand, clay, mica, wollastonite, Examples thereof include diatomaceous earth, chromium oxide, cerium oxide, pengala, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, and silicon nitride. These can be used singly or in combination of two or more. The polymer resin fine particles include, for example, polycondensation systems such as polystyrene, methacrylic acid ester, acrylic acid ester copolymer, silicone, benzoguanamine, nylon obtained by soap-free emulsion polymerization, suspension polymerization, and dispersion polymerization. And polymer particles made of a thermosetting resin.

  Of these, when glycerin fatty acid ester or polyglycerin fatty acid ester is used as the release agent, it is preferable to use silica and titanium oxide in combination. Silica and titanium oxide have strong negative chargeability and can change positively charged particles to negative chargeability in the absence of external additives.

  Typical examples of the hydrophobizing agent include the following. Dimethyldichlorosilane, trimethylchlorosilane, methyltrichlorosilane, allyldimethyldichlorosilane, allylphenyldichlorosilane, benzyldimethylchlorosilane, bromomethyldimethylchlorosilane, α-chloroethyltrichlorosilane, p-chloroethyltrichlorosilane, Chloromethyldimethylchlorosilane, chloromethyltrichlorosilane, p-chlorophenyltrichlorosilane, 3-chloropropyltrichlorosilane, 3-chloropropyltrimethoxysilane, vinyltriethoxysilane, vinylmethoxysilane, vinyl-tris (β-methoxyethoxy) ) Silane, γ-methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane, divinyldichlorosilane, dimethylvinylchlorosilane, octyl Trichlorosilane, decyl-trichlorosilane, nonyl-trichlorosilane, (4-t-propylphenyl) -trichlorosilane, (4-t-butylphenyl) -trichlorosilane, dipentyl-dichlorosilane, dihexyl-dichlorosilane, dioctyl-dichlorosilane, dinonyl -Dichlorosilane, didecyl-dichlorosilane, didodecyl-dichlorosilane, dihexadecyl-dichlorosilane, (4-t-butylphenyl) -octyl-dichlorosilane, dioctyl-dichlorosilane, didecenyl-dichlorosilane, dinonenyl-dichlorosilane, di-2-ethylhexyl-dichlorosilane, di- 3,3-dimethylpentyl-dichlorosilane, trihexyl-chlorosilane, trioctyl-chlorosilane, tridecyl-chlorosilane Dioctyl-methyl-chlorosilane, octyl-dimethyl-chlorosilane, (4-t-propylphenyl) -diethyl-chlorosilane, octyltrimethoxysilane, hexamethyldisilazane, hexaethyldisilazane, diethyltetramethyldisilazane, hexaphenyldisilazane , Hexatolyl disilazane and the like. In addition, titanate coupling agents and aluminum coupling agents can also be used.

  For mixing the external additives described above, a general powder mixer is used, but it is preferable to equip a jacket or the like to adjust the internal temperature. For example, a V-type mixer, a rocking mixer, a Laedige mixer, a Nauter mixer, a Henschel mixer and the like are preferably used.

  The above-mentioned inorganic fine particles and resin fine particles are contained (internally added) in the toner, but the effect is reduced as compared with the case of external addition, but the effect of improving transferability and durability can be obtained and the pulverization property of the toner can be improved. Can do. In addition, since external addition and internal addition can be used together to suppress embedding of externally added fine particles, excellent transferability can be stably obtained and durability can be improved.

<Other ingredients>
Further, the toner of the present invention may appropriately contain other components depending on the purpose. Examples of other components include fluidity improvers, cleaning improvers, magnetic materials, metal soaps, and the like.
The fluidity improver means a material that can be surface treated to increase hydrophobicity and prevent deterioration of flow characteristics and charging characteristics even under high humidity. For example, a silane coupling agent, a silylating agent, Examples thereof include a silane coupling agent having a fluorinated alkyl group, an organic titanate coupling agent, an aluminum coupling agent, silicone oil, and modified silicone oil.

  The cleaning property improver is added to the toner in order to remove the developer after transfer remaining on the electrostatic latent image carrier or the intermediate transfer member. For example, fatty acid such as zinc stearate, calcium stearate, stearic acid, etc. Examples thereof include polymer fine particles produced by soap-free emulsion polymerization such as metal salts, polymethyl methacrylate fine particles, and polystyrene fine particles. The polymer fine particles preferably have a relatively narrow particle size distribution, and those having a weight average particle size of 0.01 to 1 μm are suitable.

  There is no restriction | limiting in particular as said magnetic material, According to the objective, it can select suitably from well-known things, For example, iron powder, a magnetite, a ferrite etc. are mentioned. Among these, white is preferable in terms of color tone.

<Toner production method>
The method for producing the toner of the present invention is not particularly limited, and a melt-kneading pulverization method and a polymerization method, a polyaddition reaction method using an isocyanate group-containing prepolymer, a method of dissolving in a solvent, removing the solvent, and pulverizing Besides, it can also be produced by a melt spray method. Among these production methods, a melt kneading method, a polymerization method in which a monomer composition containing a specific crystalline polymer and a polymerizable monomer is directly polymerized in an aqueous phase (suspension polymerization method / emulsification method). A polyaddition reaction method in which a composition containing a specific crystalline polymer and an isocyanate group-containing prepolymer is directly extended / crosslinked with amines in an aqueous phase, dissolved in a solvent, desolvated and pulverized. It is preferable to employ a method, and a conventionally known production method can be used.

  In the melt-kneading and pulverizing method, as a device for melt-kneading toner, a batch-type twin roll, a Banbury mixer or a continuous twin-screw extruder, for example, KTK type twin-screw extruder manufactured by Kobe Steel, Toshiba Machine Co., Ltd. TEM type twin screw extruder, KCK twin screw extruder, Ikegai Iron Works PCM type twin screw extruder, Kurimoto Iron Works KEX type twin screw extruder, continuous single screw kneader, for example Buss Co-kneader etc. are preferably used.

  In the polymerization method and the polyaddition reaction method using an isocyanate group-containing prepolymer, the emulsification (formation of droplets) treatment is mandatory by applying mechanical energy in the aqueous phase. Examples of the mechanical energy applying means include strong stirring such as homomixer, ultrasonic wave, and manton gorin, or ultrasonic vibration energy applying means.

  For pulverization, coarse pulverization can be performed using a hammer mill, a rotoplex, or the like, and a fine pulverizer using a jet stream or a mechanical pulverizer can be used. The average particle size is 3 to 15 μm. It is desirable to do so. Further, the pulverized product is adjusted in particle size to 5 to 20 μm by a wind classifier or the like.

  In the external addition of the external additive to the toner base, the toner base and the external additive are mixed and stirred using a mixer to coat the toner surface while the external additive is crushed. At this time, it is important in terms of durability that external additives such as inorganic fine particles and resin fine particles are uniformly and firmly attached to the toner base.

<Toner particle size>
The weight average particle diameter of the toner is not particularly limited and can be appropriately selected according to the purpose. Is preferably 3 to 10 μm. More preferably, it is 4-7 micrometers. The smaller the particle size, the better the image sharpness and fine line reproducibility, but the toner fluidity and transferability deteriorate. Here, the weight average particle diameter of the toner can be obtained as follows.

[Weight average particle diameter of toner]
Measuring machine: Coulter Multisizer II (Beckman Coulter, Inc.)
Aperture diameter: 100 μm
Analysis software: Coulter Multisizer AccuComp version 1.19 (Beckman Coulter, Inc.)
Electrolyte: Isoton II (Beckman Coulter, Inc.)
Dispersion: Emulgen 109P (manufactured by Kao Corporation, polyoxyethylene lauryl ether, HLB: 13.6) 5% electrolyte Dispersion condition: 10 mg of a measurement sample is added to 5 mL of the dispersion, and dispersed for 1 minute with an ultrasonic disperser. Thereafter, 25 mL of an electrolytic solution is added and further dispersed for 1 minute by an ultrasonic disperser.
Measurement conditions: 100 mL of electrolyte solution and dispersion liquid are added to a beaker, 30,000 particles are measured at a concentration capable of measuring the particle size of 30,000 particles in 20 seconds, and the weight average particle size is obtained from the particle size distribution. .

<Career>
There is no restriction | limiting in particular as a carrier, Although it can select suitably according to the objective, What has a core material and the resin layer which coat | covers this core material is preferable.
There is no restriction | limiting in particular as a material of the said core material, It can select suitably from well-known things, For example, 50-90 emu / g manganese-strontium (Mn-Sr) type material, manganese-magnesium (Mn-) Mg) -based materials and the like are preferable, and highly magnetized materials such as iron powder (100 emu / g or more) and magnetite (75 to 120 emu / g) are preferable in terms of securing image density. In addition, the copper-zinc (Cu-Zn) system (30 to 80 emu / g) or the like is advantageous in that it can weaken the contact with the electrostatic latent image carrier in which the toner is in a spiked state, and is advantageous in improving the image quality. The weakly magnetized material is preferred. These may be used alone or in combination of two or more.

  The particle diameter of the core material is preferably an average particle diameter (weight average particle diameter (D50)) of 10 to 200 μm, and more preferably 40 to 100 μm. When the average particle diameter (weight average particle diameter (D50)) is less than 10 μm, in the distribution of carrier particles, the fine powder system increases, the magnetization per particle is lowered, and carrier scattering may occur. If it exceeds 200 μm, the specific surface area may decrease and toner scattering may occur, and in the case of a full color with many solid portions, reproduction of the solid portions may be particularly poor.

  The material of the resin layer is not particularly limited and can be appropriately selected from known resins according to the purpose. For example, amino resins, polyvinyl resins, polystyrene resins, halogenated olefin resins, Polyester resin, polycarbonate resin, polyethylene resin, polyvinyl fluoride resin, polyvinylidene fluoride resin, polytrifluoroethylene resin, polyhexafluoropropylene resin, copolymer of vinylidene fluoride and acrylic monomer, vinylidene fluoride And fluorinated terpolymers (triple fluorinated (multiple) copolymers) such as terpolymers of tetrafluoroethylene, vinylidene fluoride and non-fluorinated monomers, silicone resins, etc. It is done. These may be used individually by 1 type and may use 2 or more types together. Among these, a silicone resin is particularly preferable.

The silicone resin is not particularly limited and can be appropriately selected according to the purpose from generally known silicone resins. For example, a straight silicone resin consisting only of an organosilosan bond; an alkyd resin; Examples thereof include polyester resins, epoxy resins, acrylic resins, silicone resins modified with urethane resins, and the like.
Commercially available products can be used as the silicone resin. Examples of straight silicone resins include KR271, KR255, and KR152 manufactured by Shin-Etsu Chemical Co., Ltd .; SR2400, SR2406, and SR2410 manufactured by Toray Dow Corning Silicone Co., Ltd. Etc.

Commercially available products can be used as the modified silicone resin, such as KR206 (alkyd modified), KR5208 (acrylic modified), ES1001N (epoxy modified), KR305 (urethane modified) manufactured by Shin-Etsu Chemical Co., Ltd .; SR2115 (epoxy-modified), SR2110 (alkyd-modified) manufactured by Dow Corning Silicone Co., Ltd., and the like.
In addition, although a silicone resin can be used alone, it is also possible to simultaneously use a component that undergoes a crosslinking reaction, a charge amount adjusting component, and the like.

  The resin layer may contain conductive powder or the like as necessary. Examples of the conductive powder include metal powder, carbon black, titanium oxide, tin oxide, and zinc oxide. The average particle diameter of these conductive powders is preferably 1 μm or less. When the average particle diameter exceeds 1 μm, it may be difficult to control electric resistance.

For example, the resin layer is prepared by dissolving the silicone resin or the like in a solvent to prepare a coating solution, and then uniformly coating the coating solution on the surface of the core material by a known coating method, drying, and baking. It can be formed by doing. Examples of the application method include an immersion method, a spray method, and a brush coating method.
There is no restriction | limiting in particular as said solvent, Although it can select suitably according to the objective, For example, toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, cellosolve, butyl acetate, etc. are mentioned.
The baking method is not particularly limited, and may be an external heating method or an internal heating method. For example, a stationary electric furnace, a fluid electric furnace, a rotary electric furnace, a burner furnace Etc., a method using a microwave, and the like.

  The amount of the resin layer in the carrier is preferably 0.01 to 5.0% by mass. When the amount is less than 0.01% by mass, the uniform resin layer may not be formed on the surface of the core material. When the amount exceeds 5.0% by mass, the resin layer becomes thick. In some cases, granulation of carriers occurs, and uniform carrier particles may not be obtained.

When the developer is a two-component developer, the content of the carrier in the two-component developer is not particularly limited and may be appropriately selected depending on the intended purpose. % Is preferable, and 93 to 97% by mass is more preferable.
In general, the mixing ratio of the toner and the carrier of the two-component developer is preferably 1 to 10.0 parts by mass of the toner with respect to 100 parts by mass of the carrier.

<Image forming apparatus>
The image forming apparatus includes at least an electrostatic latent image carrier, a charging unit, an exposure unit, a developing unit, a transfer unit, and a fixing unit, and is appropriately selected as necessary according to a cleaning unit. It has other means, for example, static elimination means, recycling means, control means and the like. The charging unit and the exposure unit may be collectively referred to as an electrostatic latent image forming unit.

<Image forming method>
The image forming method of the present invention includes at least a charging step, an exposure step, a development step, a transfer step, and a fixing step, and a cleaning step, and other steps appropriately selected as necessary, for example, It includes a static elimination process, a recycling process, a control process, and the like. The charging process and the exposure process may be collectively referred to as an electrostatic latent image forming process.
The image forming method of the present invention can be preferably carried out by the image forming apparatus of the present invention, the charging step can be performed by the charging unit, the exposure step can be performed by the exposure unit, The developing step can be performed by the developing unit, the transferring step can be performed by the transferring unit, the fixing step can be performed by the fixing unit, and the cleaning step can be performed by the cleaning unit. The other steps can be performed by the other means.

<Electrostatic latent image carrier>
The material, shape, structure, size and the like of the electrostatic latent image carrier are not particularly limited and can be appropriately selected according to the purpose. Examples of the shape include a drum shape and a sheet. And endless belts. The structure may be a single-layer structure or a laminated structure, and the size may be appropriately selected according to the size and specifications of the image forming apparatus. Examples of the material include inorganic photoreceptors such as amorphous silicon, selenium, CdS, and ZnO; organic photoreceptors (OPC) such as polysilane and phthalopolymethine, and the like.

  For example, the amorphous silicon photosensitive member is heated to 50 to 400 ° C., and a vacuum deposition method, a sputtering method, an ion plating method, a thermal CVD method, a photo CVD method, a plasma CVD method, or the like is applied on the support. A photosensitive layer made of a-Si is formed by a film forming method. Among these, the plasma CVD method is particularly preferable, and specifically, a method in which the source gas is decomposed by direct current, high frequency, or microwave glow discharge to form a photosensitive layer made of a-Si on the support is preferable. .

  The organic photoreceptor (OPC) has (1) optical characteristics such as a wide light absorption wavelength range and a large amount of light absorption, (2) electrical characteristics such as high sensitivity and stable charging characteristics, (3) In general, it is widely applied because of the wide selection range of materials, (4) ease of production, (5) low cost, and (6) non-toxicity. The layer structure of such an organic photoreceptor is roughly divided into a single layer structure and a laminated structure.

The single-layered photoreceptor has a support and a single-layer type photosensitive layer provided on the support, and further includes a protective layer, an intermediate layer, and other layers as necessary.
The laminated structure of the photoreceptor comprises a support, and a laminate type photosensitive layer having at least a charge generation layer and a charge transport layer in this order on the support, and further includes a protective layer and an intermediate layer as necessary. And other layers.
<Charging step and charging means>
The charging step is a step of charging the surface of the electrostatic latent image carrier, and is performed by the exposure unit.
The charging means is not particularly limited as long as it can apply a voltage to the surface of the latent electrostatic image bearing member to be uniformly charged, and can be appropriately selected according to the purpose. (1) Contact type charging means for charging in contact with the electrostatic latent image carrier and (2) Non-contact type charging means for charging in a non-contact manner with the electrostatic latent image carrier.

-Contact charging means-
Examples of the contact type charging means (1) include a conductive or semiconductive charging roller, a magnetic brush, a fur brush, a film, and a rubber blade. Among these, the charging roller can significantly reduce the amount of ozone generated compared to corona discharge, and is excellent in stability during repeated use of the electrostatic latent image carrier, and effective in preventing image quality deterioration. It is.
The magnetic brush is composed of a nonmagnetic conductive sleeve that supports various ferrite particles such as Zn-Cu ferrite and a magnet roll included in the sleeve. The fur brush is formed by, for example, winding or pasting a fur subjected to a conductive treatment with carbon, copper sulfide, metal, metal oxide, or the like around a metal or a conductive metal core.

FIG. 1 is a cross-sectional view illustrating an example of a charging roller. The charging roller 310 includes a cored bar 311 as a conductive support having a cylindrical shape, a resistance adjusting layer 312 formed on the outer peripheral surface of the cored bar 311 with a uniform thickness, and the resistance adjusting layer 312. A protective layer 313 that covers the surface of the substrate and prevents leakage.
The resistance adjusting layer 312 is formed by providing a thermoplastic resin composition on the peripheral surface of the core metal 311 by extrusion molding or injection molding.
The thermoplastic resin used for the resistance adjusting layer 312 is not particularly limited and may be appropriately selected depending on the intended purpose. For example, polyethylene (PE), polypropylene (PP), polymethyl methacrylate (PMMA), Examples thereof include polystyrene (PS) and copolymers thereof (AS, ABS, etc.).

The resistance adjusting layer 312 is formed of a thermoplastic resin composition in which a polymer type ionic conductive agent is dispersed. The volume resistivity value of the resistance adjusting layer 312 is preferably 10 ⁶ to 10 ⁹ Ω · cm. When the volume resistivity value exceeds 10 ⁹ Ω · cm, the charge amount is insufficient, and the photosensitive drum may not be able to obtain a sufficient charging potential to obtain a uniform image. If the value is less than 10 ⁶ Ω · cm, there is a risk of leakage to the entire photosensitive drum.

As the polymer-type ion conductive agent, one having a resistance value of about 10 ⁶ to 10 ¹⁰ Ω · cm as a single substance and easily reducing the resistance of the resin is used. One example is a compound containing a polyether ester amide component. In order to set the resistance value of the resistance adjusting layer 312 to the above value, the blending amount is preferably 30 to 70 parts by mass with respect to 100 parts by mass of the thermoplastic resin.
In addition, a quaternary ammonium base-containing polymer compound can also be used as the polymer type ion conductive agent. Examples of the quaternary ammonium base-containing polymer compound include quaternary ammonium base-containing polyolefin. In order to set the resistance value of the resistance adjusting layer 312 to the above value, the blending amount is preferably 10 to 40 parts by mass with respect to 100 parts by mass of the thermoplastic resin.

  The polymer type ion conductive agent can be dispersed in the thermoplastic resin by a biaxial kneader, a kneader or the like. Since the polymer type ionic conductive agent is uniformly dispersed at the molecular level in the thermoplastic resin composition, the resistance adjusting layer 312 has a conductive material dispersed as seen in the resistance adjusting layer in which a conductive pigment is dispersed. There is no variation in resistance value due to defects. In addition, since the polymer type ion conductive agent is a polymer compound, it is uniformly dispersed and fixed in the thermoplastic resin composition, and bleedout hardly occurs.

The protective layer 313 is formed such that its resistance value is larger than the resistance value of the resistance adjustment layer 312. As a result, leakage to the defective portion of the photosensitive drum is avoided. However, if the resistance value of the protective layer 313 is excessively increased, the charging efficiency is lowered. Therefore, the difference between the resistance value of the protective layer 313 and the resistance value of the resistance adjustment layer 312 is preferably 10 ³ Ω · cm or less. .

  As a material for forming the protective layer 313, a resin material is preferable from the viewpoint of good film formability. As the resin material, for example, a fluororesin, a polyamide resin, a polyester resin, a polyvinyl acetal resin and the like are preferable from the viewpoint of excellent non-adhesiveness and preventing toner adhesion. In addition, since the resin material generally has electrical insulation, if the protective layer 313 is formed of the resin material alone, the characteristics of the charging roller are not satisfied. Therefore, the resistance value of the protective layer 313 is adjusted by dispersing various conductive agents in the resin material. In order to improve the adhesion between the protective layer 303 and the resistance adjustment layer 302, a reactive curing agent such as isocyanate may be dispersed in the resin material.

  The charging roller 310 is connected to a power source and is applied with a predetermined voltage. The voltage may be only a direct current (DC) voltage, but is preferably a voltage obtained by superimposing an alternating current (AC) voltage on a DC voltage. By thus applying the AC voltage, the surface of the photosensitive drum can be more uniformly charged.

FIG. 2 is a schematic diagram showing an example in which a contact-type charging roller 310 as shown in FIG. 1 is applied to an image forming apparatus as a charging unit. In FIG. 2, around a photosensitive drum 321 as an electrostatic latent image carrier, a charging roller 310 for charging the surface of the photosensitive drum, an exposure unit 323 for forming a latent image on a charging processing surface, Developing means 324 for forming a visible image by attaching toner to the latent image on the surface of the photosensitive drum, transfer means 325 for transferring the visible image on the formed photosensitive drum onto the recording medium 326, on the recording medium A fixing means 327 for fixing the visible image, a cleaning means 330 for removing and collecting the residual toner on the photosensitive drum, and a static eliminating device 331 for removing the residual potential on the photosensitive drum are arranged in this order. ing.
As the charging unit 310, a contact type charging roller 310 shown in FIG. 1 is provided, and the surface of the photosensitive drum 321 is uniformly charged by the charging roller 310.

-Non-contact charging means-
The non-contact charging means (2) includes, for example, a non-contact charger using a corona discharge, a needle electrode device, a solid discharge element; a conductive material disposed with a minute gap with respect to the electrostatic latent image carrier. Or a semiconductive charging roller.
The corona discharge is a non-contact charging method that gives positive or negative ions generated by corona discharge in the air to the surface of the electrostatic latent image carrier, and gives a constant amount of charge to the electrostatic latent image carrier. There are a coroton charger having characteristics and a scorotron charger having characteristics that give a constant potential.

The coroton charger is composed of a casing electrode that occupies a half space around the discharge wire, and a discharge wire placed almost at the center thereof.
The scorotron charger is obtained by adding a grid electrode to the corotron charger, and the grid electrode is provided at a position 1.0 to 2.0 mm away from the surface of the electrostatic latent image carrier.

FIG. 3 is a schematic diagram illustrating an example in which a non-contact type corona charger is applied to an image forming apparatus as a charging unit. In FIG. 3, the same components as those in FIG. 2 are denoted by the same reference numerals.
As the charging means, a non-contact type corona charger 314 is provided, and the surface of the photosensitive drum 321 is uniformly charged by the corona charger 314.
The charging roller provided with a minute gap with respect to the electrostatic latent image carrier is an improvement of the charging roller so as to have a minute gap with respect to the electrostatic latent image carrier. The fine gap is preferably 10 to 200 μm, and more preferably 10 to 100 μm.

  FIG. 4 is a schematic diagram illustrating an example of a non-contact charging roller. In FIG. 4, the charging roller 310 is disposed with a minute gap H with respect to the photosensitive drum 321. The minute gap H is set by causing the spacer member surface to contact the surface of the photosensitive drum 321 by, for example, winding a spacer member having a certain thickness around the non-image forming regions at both ends of the charging roller 310. can do. In FIG. 4, 304 is a power source.

  In FIG. 4, as a method for maintaining the minute gap H, a film 302 is wound around both ends of the charging roller 310 to form a spacer member. The spacer 302 is brought into contact with the photosensitive surface of the electrostatic latent image carrier to obtain a certain minute gap H in the image area of the charging roller and the electrostatic latent image carrier. The applied bias applies an AC superposition type voltage, and charges the electrostatic latent image carrier by a discharge generated in a small gap between the charging roller and the electrostatic latent image carrier. As shown in FIG. 4, the accuracy of maintaining the minute gap H is improved by pressing the shaft 311 of the charging roller with the spring 303.

The spacer member may be integrally formed with the charging roller. At this time, at least the surface of the gap portion is an insulator. As a result, the discharge at the gap portion is eliminated, and the discharge product is deposited on the gap portion, and the adhesion of the discharge product prevents the toner from adhering to the gap portion and spreading the gap.
Moreover, as the spacer member, a heat shrinkable tube may be used. Examples of such heat-shrinkable tubes include Sumitubes for 105 ° C. (trade name: F105 ° C., manufactured by Sumitomo Chemical Co., Ltd.).

<Exposure process and exposure means>
The exposure can be performed, for example, by exposing the surface of the latent electrostatic image bearing member imagewise using the exposure unit.
The optical system in the exposure is roughly classified into an analog optical system and a digital optical system. The analog optical system is an optical system that projects an original directly onto an electrostatic latent image carrier by an optical system. The digital optical system receives image information as an electrical signal and converts it into an optical signal. It is an optical system that exposes an electrostatic latent image carrier to form an image.
The exposure means is not particularly limited as long as the surface of the electrostatic latent image carrier charged by the charging means can be exposed like an image to be formed, and is appropriately selected according to the purpose. For example, various exposure devices such as a copying optical system, a rod lens array system, a laser optical system, a liquid crystal shutter optical system, and an LED optical system can be used.
In the present invention, a back light system in which imagewise exposure is performed from the back surface side of the electrostatic latent image carrier may be adopted.

<Development process and development means>
The developing step is a step of developing the electrostatic latent image using a toner or a developer to form a visible image.
The visible image can be formed, for example, by developing the electrostatic latent image using the toner or the developer, and can be performed by the developing unit.
The developing means is not particularly limited as long as it can be developed using toner or developer, for example, and can be appropriately selected from known ones. For example, the toner or developer is accommodated, and Preferable examples include those having at least developing means capable of bringing the toner or developer into contact or non-contact with the electrostatic latent image.

The developing means may be of a dry development type or a wet development type. Further, it may be a single color presenting means or a multicolor developing means. Preferred examples include those possessed.
In the developing means, for example, the toner and the carrier are mixed and stirred, and the toner is charged by friction at that time, and held on the surface of the rotating magnet roller in a raised state, thereby forming a magnetic brush. . Since the magnet roller is disposed in the vicinity of the electrostatic latent image carrier, a part of the toner constituting the magnetic brush formed on the surface of the magnet roller is electrostatically attracted by the static force. It moves to the surface of the electrostatic latent image carrier. As a result, the electrostatic latent image is developed with the toner, and a visible image is formed with the toner on the surface of the electrostatic latent image carrier.
The developer accommodated in the developing device is a developer containing the toner, but the developer may be a one-component developer or a two-component developer.

-One-component developing means-
As the one-component developing means, a one-component developing device having a developer carrier to which toner is supplied and a layer thickness regulating member that forms a thin layer of toner on the surface of the developer carrier is preferably used.
FIG. 5 is a schematic diagram illustrating an example of a one-component developing device. This one-component developing device uses a one-component developer made of toner, forms a toner layer on a developing roller 402 as a developer carrier, and uses the toner layer on the developing roller 402 as an electrostatic latent image carrier. The photosensitive drum 1 is conveyed so as to be in contact with the photosensitive drum 1, thereby performing contact one-component development for developing the electrostatic latent image on the photosensitive drum 1.

  In FIG. 5, the toner in the casing 401 is agitated by the rotation of an agitator 411 as agitation means and mechanically supplied to a supply roller 412 as a toner supply member. The supply roller 412 is formed of foamed polyurethane or the like, has flexibility, and has a structure in which toner can be easily held in a cell having a diameter of 50 to 500 μm. Further, the supply roller has a relatively low JIS-A hardness of 10 to 30 °, and can be brought into contact with the developing roller 402 uniformly.

  The supply roller 412 is driven to rotate in the same direction as the developing roller 402, that is, the surface of the supply roller 412 moves in the opposite direction at the opposing portion of both rollers. The linear speed ratio (supply roller / developing roller) of both rollers is preferably 0.5 to 1.5. Further, the supply roller 412 may be rotated so that the surfaces of the supply roller 412 move in the same direction as the developing roller 402, that is, at the opposite portions of the two rollers. In this embodiment, the supply roller 412 rotates in the same direction as the developing roller 402, and the linear speed ratio is set to 0.9. The biting amount of the supply roller 412 with respect to the developing roller 402 is set to 0.5 to 1.5 mm. In this embodiment, when the unit effective width is 240 mm (A4 size vertical), the necessary torque is 14.7 to 24.5 N · cm.

  The developing roller 402 has a surface layer made of a rubber material on a conductive substrate, has a diameter of 10 to 30 mm, and appropriately roughens the surface to have a surface roughness Rz of 1 to 4 μm. The value of the surface roughness Rz is 13 to 80% with respect to the average particle diameter of the toner, whereby the toner is conveyed without being buried in the surface of the developing roller 402. In particular, the surface roughness Rz of the developing roller 402 is preferably in the range of 20 to 30% of the average particle size of the toner so as not to retain a remarkably low charged toner.

  Examples of the rubber material include silicone rubber, butadiene rubber, NBR rubber, hydrin rubber, EPDM rubber, and the like. Further, it is preferable to coat the surface of the developing roller 402 with a coating layer in order to stabilize the quality with time. Examples of the material for the coating layer include silicone materials and Teflon (registered trademark) materials. The silicone material is excellent in toner chargeability, and the Teflon (registered trademark) material is excellent in releasability. In order to obtain conductivity, a conductive material such as carbon black can be appropriately contained. The thickness of the coat layer is preferably 5 to 50 μm. If it is out of this range, problems such as easy cracking may occur.

Toner having a predetermined polarity (negative polarity in the case of the present embodiment) existing on or inside the supply roller 412 is pinched by the developing roller 402 that rotates in the opposite direction at the contact point due to the rotation. A negatively charged charge is obtained by the charging effect and is held on the developing roller 402 by an electrostatic force and by a conveying effect by the surface roughness of the developing roller 402. However, the toner layer on the developing roller 402 at this time is not uniform and is considerably excessively attached (1 to 3 mg / cm ² ). Accordingly, a toner thin layer having a uniform layer thickness is formed on the developing roller 402 by bringing a regulating blade 413 as a layer thickness regulating member into contact with the developing roller 402. The restriction blade 413 is a so-called belly contact where the tip is directed downstream with respect to the rotation direction of the developing roller 402 and the central portion of the restriction blade 413 comes into contact, but it can also be set in the reverse direction. It is also possible to realize edge contact.

  As the material of the regulating blade, a metal such as SUS304 is preferable, and the thickness is 0.1 to 0.15 mm. In addition to the metal, a rubber material such as polyurethane rubber having a thickness of 1 to 2 mm or a resin material having a relatively high hardness such as a silicone resin can be used. In addition, since the resistance can be reduced by mixing carbon black or the like other than metal, it is possible to form an electric field between the developing roller 402 by connecting a bias power source.

  The regulating blade 413 as the layer thickness regulating member is preferably 10 to 15 mm as a free end length from the holder. If the free end length exceeds 15 mm, the developing means becomes large and cannot be stored compactly in the image forming apparatus. If it is less than 10 mm, vibration occurs when the regulating blade comes into contact with the surface of the developing roller 402. In some cases, an abnormal image such as unevenness in the horizontal direction is likely to occur on the image.

  The contact pressure of the regulating blade 413 is preferably in the range of 0.049 to 2.45 N / cm. If the contact pressure exceeds 2.45 N / cm, the toner adhesion amount on the developing roller 402 decreases and the toner charge amount increases excessively, so the development amount may decrease and the image density may decrease. If it is less than 0.049 N / cm, a thin layer may not be formed uniformly, and the toner mass may pass through the regulating blade, and the image quality may be significantly lowered. In this embodiment, the developing roller 402 has a JIS-A hardness of 30 °, the regulating blade 413 is a SUS plate having a thickness of 0.1 mm, and the contact pressure is set to 60 gf / cm. At this time, the target toner adhesion amount on the developing roller could be obtained.

Further, the contact angle of the regulating blade 413 as the layer thickness regulating member is preferably 10 to 45 ° with respect to the tangent line of the developing roller 402 in the direction in which the tip faces the downstream side of the developing roller 402. A portion unnecessary for forming a thin layer of toner sandwiched between the regulating blade 413 and the developing roller 402 is peeled off from the developing roller 402 and is 0.4 to 0.8 mg / cm ² per unit area which is a target range. A thin layer having a uniform thickness is formed. The toner charge at this time is finally in the range of −10 to −30 μC / g in this embodiment, and is developed to face the electrostatic latent image on the photosensitive drum 1.
Therefore, according to the one-component developing device of this embodiment, the distance between the surface of the photosensitive drum 1 and the surface of the developing roller 402 is further narrower than in the case of the conventional two-component developing unit, the developing ability is increased, and the further low potential is achieved. But development is possible.

-Two-component developing means-
The two-component developing means has a magnetic field generating means fixed inside, and a two-component development having a rotatable developer carrier carrying a two-component developer comprising a magnetic carrier and toner on the surface. A device is preferred.

  FIG. 6 is a schematic view showing an example of a two-component developing device using a two-component developer composed of toner and a magnetic carrier. In the two-component developing device of FIG. 6, the two-component developer is stirred and conveyed by a screw 441 and supplied to a developing sleeve 442 as a developer carrier. The two-component developer supplied to the developing sleeve 442 is regulated by a doctor blade 443 as a layer thickness regulating member, and the amount of developer supplied is controlled by a doctor gap which is a distance between the doctor blade 443 and the developing sleeve 442. The If the doctor gap is too small, the developer amount is too small and the image density is insufficient. Conversely, if the doctor gap is too large, the developer amount is excessively supplied and the photosensitive drum as an electrostatic latent image carrier. There arises a problem that carrier adhesion occurs on 1. Therefore, the developing sleeve 442 is provided with a magnet as a magnetic field generating means for generating a magnetic field so that the developer is sprinkled on the peripheral surface thereof, so as to follow a normal magnetic field line generated from the magnet. Then, the developer is spiked in a chain shape on the developing sleeve 442 to form a magnetic brush.

  The developing sleeve 442 and the photosensitive drum 1 are disposed so as to be close to each other with a certain gap (developing gap) therebetween, and a developing region is formed in a portion facing both. The developing sleeve 442 is formed of a non-magnetic material such as aluminum, brass, stainless steel, or conductive resin in a cylindrical shape, and is rotated by a rotation drive mechanism (not shown). The magnetic brush is transferred to the developing area by the rotation of the developing sleeve 442. A developing voltage is applied to the developing sleeve 442 from a developing power source (not shown), and the toner on the magnetic brush is separated from the carrier by the developing electric field formed between the developing sleeve 442 and the photosensitive drum 1, and the photosensitive drum 1. It is developed on the upper electrostatic latent image. An alternating current may be superimposed on the development voltage.

The development gap is preferably about 5 to 30 times the particle size of the developer, and is preferably set to 0.5 to 1.5 mm if the developer particle size is 50 μm. If the development gap is wider than this, the desired image density may be difficult to achieve.
The doctor gap is preferably the same as or slightly larger than the development gap. The drum diameter and drum linear speed of the photosensitive drum 1 and the sleeve diameter and sleeve linear speed of the developing sleeve 442 are determined by restrictions such as the copying speed and the size of the apparatus. The ratio of the sleeve linear velocity to the drum linear velocity is preferably 1.1 or more in order to obtain a necessary image density. It is also possible to control the process conditions by installing a sensor at a position after development and detecting the toner adhesion amount from the optical reflectance.

<Transfer process and transfer means>
The transfer step is a step of transferring the visible image to a recording medium, and is performed using a transfer unit. As the transfer means. Using a transfer unit that directly transfers a visible image on the electrostatic latent image bearing member to a recording medium, or an intermediate transfer member, after the primary transfer of the visible image onto the intermediate transfer member, the visible image is It is roughly divided into secondary transfer means for secondary transfer onto a recording medium.
The transfer can be performed, for example, by charging the electrostatic latent image carrier using a transfer charger, and can be performed by the transfer unit. The transfer unit preferably includes a primary transfer unit that forms a composite transfer image by transferring a visible image onto an intermediate transfer member, and a secondary transfer unit that transfers the composite transfer image onto a recording medium. .

-Intermediate transfer member-
There is no restriction | limiting in particular as said intermediate transfer body, According to the objective, it can select suitably from well-known transfer bodies, For example, a transfer belt etc. are mentioned suitably.
The intermediate transfer member preferably has a static friction coefficient of 0.1 to 0.6, more preferably 0.3 to 0.5. The volume resistance of the intermediate transfer member is preferably from several Ωcm to 10 ³ Ωcm. Thus, by setting the volume resistance to several Ωcm or more and 10 ³ Ωcm or less, the intermediate transfer member itself can be prevented from being charged, and the charge imparted by the charge imparting means hardly remains on the intermediate transfer member. Transfer unevenness during the next transfer can be prevented. Further, it is possible to easily apply a transfer bias at the time of secondary transfer.

There is no restriction | limiting in particular as a material of the said intermediate transfer body, Although it can select suitably according to the objective from well-known materials, the following are suitable.
(1) A material having a high Young's modulus (tensile modulus) is used as a single layer belt. For example, PC (polycarbonate), PVDF (polyvinylidene fluoride), PAT (polyalkylene terephthalate), PC (polycarbonate) and PAT (Polyalkylene terephthalate) blend material, ETFE (ethylene tetrafluoroethylene copolymer) and PC blend material, ETFE and PAT blend material, PC and PAT blend material, thermosetting of carbon black dispersion Examples thereof include polyimide. These single-layer belts having a high Young's modulus have the advantage that the amount of deformation with respect to stress during image formation is small, and rib displacement is unlikely to occur particularly during color image formation.
(2) A belt having a two- to three-layer structure in which a belt having a high Young's modulus of (1) is used as a base layer and a surface layer or an intermediate layer is provided on the outer periphery thereof. It has a performance capable of preventing the line image from being lost due to the hardness of the belt.
(3) It is an elastic belt having a relatively low Young's modulus using resin, rubber or elastomer, and such an elastic belt has an advantage that almost no void in the line image occurs due to its softness. In addition, the elastic belt is wider than the drive roll and stretch roll, and the elasticity of the belt ears protruding from the roll can be used to prevent meandering, thus reducing costs without requiring ribs or meandering prevention devices. it can.
Among these, the elastic belt (3) is particularly preferable.

  The elastic belt is deformed corresponding to a toner layer and a recording medium having poor smoothness in the transfer portion. In other words, the elastic belt deforms following local irregularities, so that it is possible to obtain good adhesion without excessively increasing the transfer pressure with respect to the toner layer, and recording with poor flatness without missing characters. A transfer image with excellent uniformity can be obtained even on a medium.

  There is no restriction | limiting in particular as resin used for the said elastic belt, Although it can select suitably according to the objective, For example, a polycarbonate, a fluororesin (ETFE, PVDF), a polystyrene, chloropolystyrene, poly-alpha-methylstyrene Styrene-butadiene copolymer, styrene-vinyl chloride copolymer, styrene-vinyl acetate copolymer, styrene-maleic acid copolymer, styrene-acrylic acid ester copolymer (for example, styrene-methyl acrylate copolymer) Styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-phenyl acrylate copolymer, etc.), styrene-methacrylic acid ester copolymer (for example, Styrene-methyl methacrylate copolymer, styrene-methyl Styrenic resins (styrene or styrene substituted) such as ethyl crylate copolymer, styrene-phenyl methacrylate copolymer, styrene-α-methyl chloroacrylate copolymer, styrene-acrylonitrile-acrylic ester copolymer, etc. Homopolymer or copolymer), methyl methacrylate resin, butyl methacrylate resin, ethyl acrylate resin, butyl acrylate resin, modified acrylic resin (for example, silicone-modified acrylic resin, vinyl chloride resin-modified acrylic resin, Acrylic-urethane resin, etc.), vinyl chloride resin, styrene-vinyl acetate copolymer, vinyl chloride-vinyl acetate copolymer, rosin-modified maleic acid resin, phenol resin, epoxy resin, polyester resin, polyester polyurethane resin, polyethylene, polypropylene , Poly Tajien, polyvinylidene chloride, ionomer resins, polyurethane resins, silicone resins, ketone resins, ethylene - ethyl acrylate copolymer, xylene resin, polyvinyl butyral resin, polyamide resin and modified polyphenylene oxide resins. These may be used individually by 1 type and may use 2 or more types together.

  There is no restriction | limiting in particular as rubber | gum used for the said elastic belt, According to the objective, it can select suitably, For example, natural rubber, butyl rubber, fluororubber, acrylic rubber, EPDM, NBR, acrylonitrile butadiene styrene rubber, isoprene Rubber, styrene-butadiene rubber, butadiene rubber, ethylene-propylene rubber, ethylene-propylene terpolymer, chloroprene rubber, chlorosulfonated polyethylene, chlorinated polyethylene, urethane rubber, syndiotactic 1,2-polybutadiene, epichlorohydrin series Examples thereof include rubber, silicone rubber, fluorine rubber, polysulfide rubber, polynorbornene rubber, and hydrogenated nitrile rubber. These may be used individually by 1 type and may use 2 or more types together.

  There is no restriction | limiting in particular as an elastomer used for the said elastic belt, According to the objective, it can select suitably, For example, a polystyrene-type thermoplastic elastomer, a polyolefin-type thermoplastic elastomer, a polyvinyl chloride-type thermoplastic elastomer, a polyurethane-type thermoplasticity Examples thereof include elastomers, polyamide-based thermoplastic elastomers, polyurea thermoplastic elastomers, polyester-based thermoplastic elastomers, and fluororesin-based thermoplastic elastomers. These may be used individually by 1 type and may use 2 or more types together.

  The conductive agent for adjusting the resistance value used in the elastic belt is not particularly limited and may be appropriately selected depending on the intended purpose. For example, metal powder such as carbon black, graphite, aluminum, nickel; tin oxide, titanium oxide And conductive metal oxides such as antimony oxide, indium oxide, potassium titanate, antimony oxide-tin oxide composite oxide (ATO), and indium oxide-tin oxide composite oxide (ITO). The conductive metal oxide may be coated with insulating fine particles such as barium sulfate, magnesium silicate, and calcium carbonate.

  Further, the surface layer of the elastic belt prevents contamination of the electrostatic latent image carrier by the elastic material, reduces the surface friction resistance to the transfer belt surface, and reduces the adhesion force of the toner, thereby cleaning and secondary transfer properties. What can be increased is required. For example, materials that use one or more of polyurethane, polyester, epoxy resin, etc., can reduce surface energy and improve lubricity, such as fluorine resin, fluorine compound, fluorocarbon, titanium dioxide, silicon carbide It is possible to disperse and use such powders and particles. Further, it is also possible to use a material having a surface energy reduced by forming a fluorine-rich layer on the surface by performing a heat treatment like the fluorine-based rubber material.

  The method for producing the elastic belt is not particularly limited and may be appropriately selected depending on the intended purpose. For example, a centrifugal molding method in which a material is poured into a rotating cylindrical mold to form a belt, or a liquid paint is sprayed. Spray coating to form a film, dipping method in which a cylindrical mold is dipped in a solution of the material, casting method to inject into an inner mold and an outer mold, a compound is wrapped around a cylindrical mold and added For example, a method of performing sulfur polishing.

The method for preventing the elastic belt from stretching is not particularly limited and may be appropriately selected depending on the intended purpose. (1) A method for forming a rubber layer on a core layer having little elongation, (2 And a method of adding a material for preventing elongation to the core layer.
There is no restriction | limiting in particular as a material which comprises the core layer which prevents the said elongation, Although it can select suitably according to the objective, For example, natural fibers, such as cotton and silk; Polyester fiber, nylon fiber, acrylic fiber , Polyolefin fibers, polyvinyl alcohol fibers, polyvinyl chloride fibers, polyvinylidene chloride fibers, polyurethane fibers, polyacetal fibers, polyfluoroethylene fibers, phenol fibers, and other synthetic fibers; carbon fibers, glass fibers, boron fibers, and other inorganic fibers; iron Examples thereof include metal fibers such as fibers and copper fibers, and those made into a woven or yarn shape using these materials are preferably used.
The yarn may be twisted by one or a plurality of filaments, such as one twisted yarn, one-twisted yarn, various twisted yarns, or double yarn. The yarn can also be used after being subjected to an appropriate conductive treatment. Further, the woven fabric can be any woven fabric such as knitted weave, a cross-woven fabric can also be used, and a conductive treatment may be used.

There is no restriction | limiting in particular as a manufacturing method of the said core body layer, Although it can select suitably according to the objective, For example, (1) Covering the woven fabric woven in the cylinder shape etc. on a metal mold | die etc. (2) A method of providing a covering layer on one or both sides of a core layer by immersing a woven fabric woven in a cylindrical shape in liquid rubber or the like, and (3) a thread on a mold or the like at an arbitrary pitch. For example, a method of winding in a spiral shape and providing a coating layer thereon may be used.
The thickness of the coating layer depends on the hardness of the coating layer, but if it is too thick, the surface expands and contracts and cracks are likely to occur in the surface layer. Also, it is not preferable that the thickness is too large (about 1 mm or more) because the amount of expansion / contraction increases and the expansion and contraction of the image increases.

The transfer unit (the primary transfer unit and the secondary transfer unit) has at least a transfer unit that peels and charges the visible image formed on the electrostatic latent image carrier to the recording medium side. Is preferred. There may be one transfer unit or two or more transfer units. Examples of the transfer device include a corona transfer device using corona discharge, a transfer belt, a transfer roller, a pressure transfer roller, and an adhesive transfer device.
The recording medium is typically plain paper, but is not particularly limited as long as it can transfer an unfixed image after development, and can be appropriately selected according to the purpose. PET for OHP A base or the like can also be used.

-Transfer means of tandem type image forming apparatus-
The tandem type image forming apparatus has a plurality of image forming elements including at least an electrostatic latent image carrier, a charging unit, a developing unit, and a transfer unit. In this tandem type image forming apparatus, four image forming elements for yellow, magenta, cyan, and black are mounted, and each visible image is created in parallel with the four image forming elements, and is recorded on a recording medium or an intermediate transfer member. Therefore, a full color image can be formed at a higher speed.

  As the tandem type image forming apparatus, (1) as shown in FIG. 7, the surface moves so as to pass through a transfer position which is a region facing each electrostatic latent image carrier 1 of a plurality of image forming elements. A direct transfer system in which the visible image formed on each electrostatic latent image carrier 1 is sequentially transferred to the recording medium S by the transfer means 2, and (2) a plurality of images as shown in FIG. After the visible image on each electrostatic latent image carrier 1 of the forming element is sequentially transferred to the intermediate transfer member 4 by the primary transfer unit 2, the image on the intermediate transfer member 4 is recorded on the recording medium S by the secondary transfer unit 5. There is an indirect transfer method that performs batch transfer. In FIG. 8, the transfer device 5 serving as a transfer unit is a transfer conveyance belt, but may be a roller shape.

Comparing the direct transfer method (1) and the indirect transfer method (2), the direct transfer method (1) is a tandem type image forming unit T in which the electrostatic latent image carriers 1 are arranged. The sheet feeding device 6 must be disposed on the upstream side, and the fixing device 7 serving as a fixing unit must be disposed on the downstream side, which increases the size of the recording medium in the conveying direction. On the other hand, in the indirect transfer method (2), the secondary transfer position can be set relatively freely, and the paper feeding device 6 and the fixing device 7 are arranged so as to overlap the tandem type image forming unit T. There is an advantage that downsizing is possible.
In the direct transfer method (1), the fixing device 7 is disposed close to the tandem image forming unit T in order not to increase the size in the recording medium conveyance direction. Therefore, the fixing device 7 cannot be disposed with a sufficient margin that the recording medium S can bend, and an impact when the leading end of the recording medium S enters the fixing device 7 (particularly with a thick recording medium). In addition, the fixing device 7 tends to affect upstream image formation due to the speed difference between the recording medium conveyance speed when passing through the fixing device 7 and the recording medium conveyance speed by the transfer conveyance belt. On the other hand, in the indirect transfer method (2), the fixing device 7 can be arranged with a sufficient margin that the recording medium S can be bent, and therefore the fixing device 7 hardly affects the image formation.

  For these reasons, indirect transfer systems have recently attracted attention. In this type of color image forming apparatus, as shown in FIG. 8, the transfer residual toner remaining on the electrostatic latent image carrier 1 after the primary transfer is removed by a cleaning device 8 as a cleaning unit, and the electrostatic latent image is thus removed. The surface of the carrier 1 is cleaned to prepare for the image formation again. Further, the transfer residual toner remaining on the intermediate transfer body 4 after the secondary transfer is removed by the intermediate transfer body cleaning device 9 to clean the surface of the intermediate transfer body 4 to prepare for image formation again.

<Fixing process and fixing means>
The fixing step is a step of fixing the visible image transferred to the recording medium using a fixing unit.
The fixing unit is not particularly limited and may be appropriately selected according to the purpose. A fixing device having a fixing member and a heat source for heating the fixing member is preferably used.
The fixing member is not particularly limited as long as it can abut against each other to form a nip portion, and can be appropriately selected according to the purpose. For example, a combination of an endless belt and a roller, a roller and a roller, The heating method from the surface of the fixing member by a combination of an endless belt and a roller or induction heating can be used in order to reduce the warm-up time and realize energy saving. It is preferable to use it.

  Examples of the fixing member include known heating and pressing means (combination of heating means and pressing means). In the case of a combination of the endless belt and the roller, for example, a combination of a heating roller, a pressure roller, and an endless belt may be used as the heating and pressing unit, and the combination of the roller and the roller may be used. In this case, for example, a combination of a heating roller and a pressure roller can be used.

  When the fixing member is an endless belt, the endless belt is preferably formed of a material having a small heat capacity. For example, an embodiment in which an offset prevention layer is provided on a substrate may be used. Examples of the material for forming the base include nickel and polyimide, and examples of the material for forming the offset prevention layer include silicone rubber and fluorine-based resin.

  When the fixing member is a roller, the cored bar of the roller is preferably formed of an inelastic member to prevent deformation (deflection) due to high pressure. There is no restriction | limiting in particular as this inelastic member, Although it can select suitably according to the objective, For example, high thermal conductivity bodies, such as aluminum, iron, stainless steel, brass, are mentioned suitably. Moreover, it is preferable that the surface of the roller is covered with an offset prevention layer. The material for forming the offset prevention layer is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include RTV silicone rubber, tetrafluoroethylene-perfluoroalkyl vinyl ether (PFA), and polytetrafluoroethylene. (PTFE).

In the fixing step, the image by the toner may be transferred to the recording medium, and the recording medium on which the image has been transferred may be passed through the nip portion to fix the image to the recording medium. The image may be transferred and fixed to the recording medium at the nip portion at the same time.
The fixing step may be performed each time the toner of each color is transferred to the recording medium, or may be performed at the same time in a state where the toner of each color is stacked.

The nip portion is formed by bringing at least two fixing members into contact with each other.
The surface pressure of the nip portion is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 55N / cm ² or more, more preferably ^{70~500N / cm 2, 60~300N / cm} 2 Is more preferable. If the surface pressure of the nip portion is too high, the durability of the roller may decrease. On the other hand, when the surface pressure of the nip portion is less than 55 N / cm ² , the offset prevention property may be insufficient.

  The temperature at which the image is fixed to the recording medium by the toner (that is, the surface temperature of the fixing member by the heating means) is not particularly limited and may be appropriately selected depending on the intended purpose. ° C is preferred, and 150 to 220 ° C is more preferred. If the fixing temperature is less than 120 ° C, the fixability may be insufficient, and if it exceeds 240 ° C, it is not preferable in terms of realizing energy saving.

  As the fixing means, (1) an aspect in which the fixing means has at least one of a roller and a belt, is heated from a surface not in contact with the toner, and the transferred image transferred onto the recording medium is fixed by heating and pressing. (Internal heating system) and (2) A fixing unit has at least one of a roller and a belt, and heats and presses a transfer image transferred onto a recording medium by heating from the surface in contact with the toner. (External heating method). It is also possible to use a combination of both.

As the internal heating type fixing means (1), for example, the fixing member itself has a heating means inside. Examples of such heating means include a heat source such as a heater and a halogen lamp.
As the (2) external heating type fixing means, for example, at least a part of the surface of at least one of the fixing members is preferably heated by the heating means. There is no restriction | limiting in particular as such a heating means, According to the objective, it can select suitably, For example, an electromagnetic induction heating means etc. are mentioned.

There is no restriction | limiting in particular as said electromagnetic induction heating means, Although it can select suitably according to the objective, What has a means to generate | occur | produce a magnetic field and a means to generate | occur | produce heat | fever by electromagnetic induction, etc. are suitable.
The electromagnetic induction heating means includes, for example, an induction coil disposed so as to be close to the fixing member (for example, a heating roller), a shielding layer provided with the induction coil, and an induction coil of the shielding layer. What consists of an insulating layer provided in the other side of the provided surface is preferable. In this case, it is preferable that the heating roller is formed of a magnetic material or a heat pipe.
The induction coil is arranged in a state of wrapping at least a semi-cylindrical portion on the opposite side of the contact portion between the heating roller and the fixing member (for example, a pressure roller, an endless belt, etc.) of the heating roller. Is preferred.

-Internal heating type fixing means-
FIG. 9 is a belt-type fixing device showing an example of an internal heating type fixing means. The belt-type fixing device 510 in FIG. 9 includes a heating roller 511, a fixing roller 512, a fixing belt 513, and a pressure roller 514.
The fixing belt 513 is stretched by a heating roller 511 and a fixing roller 512 that are rotatably arranged inside, and is heated to a predetermined temperature by the heating roller 511. The heating roller 511 has a built-in heating source 515 and is designed so that the temperature can be adjusted by a temperature sensor 517 attached in the vicinity of the heating roller 511. The fixing roller 512 is rotatably disposed inside the fixing belt 513 and in contact with the inner surface of the fixing belt 513. The pressure roller 514 is in contact with the outer side of the fixing belt 513 and the outer surface of the fixing belt 513 so as to press the fixing roller 512 and is rotatably arranged. Further, the surface hardness of the fixing belt 513 is lower than the surface hardness of the pressure roller 514, and the nip portion N formed between the fixing roller 512 and the pressure roller 514 has an introduction side end and a discharge side of the recording medium S. An intermediate region located between the ends is located closer to the fixing roller 512 than the introduction side end and the discharge side end.

In the belt-type fixing device 510 shown in FIG. 9, first, the recording medium S on which the toner image T to be fixed is formed is conveyed to the heating roller 511. The toner image T on the recording medium S is heated and melted by the heating roller 511 and the fixing belt 513 heated to a predetermined temperature by the action of the built-in heating source 515. In this state, the recording medium S is inserted into a nip portion N formed between the fixing roller 512 and the pressure roller 514. The recording medium S inserted into the nip N is brought into contact with the surface of the fixing belt 513 that rotates in conjunction with the rotation of the fixing roller 512 and the pressure roller 514 and is pressed when passing through the nip N. The toner image T is fixed on the recording medium S.
Next, the recording medium S on which the toner image T is fixed passes between the fixing roller 512 and the pressure roller 514, is peeled off from the fixing belt 513, and is conveyed to a tray (not shown). At this time, the recording medium S is discharged toward the pressure roller 514, and the winding of the recording medium S around the fixing belt 513 is prevented. The fixing belt 513 is cleaned by the cleaning roller 516.

Further, the heat roll type fixing device 515 shown in FIG. 10 includes a heating roller 520 as the fixing member and a pressure roller 530 disposed in contact therewith.
The heating roller 520 has a hollow metal cylinder 521, the surface of which is covered with an offset prevention layer 522, and a heating lamp 523 is disposed therein. The pressure roller 530 includes a metal cylinder 531 and the surface thereof is covered with an offset prevention layer 532. In the pressure roller 530, the metal cylinder 531 may have a hollow shape, and a heating lamp 533 may be disposed therein.
The heating roller 520 and the pressure roller 530 are urged by a spring (not shown), and are rotatably provided in a pressure-contacted state to form a nip portion N. Further, the surface hardness of the offset prevention layer 522 in the heating roller 520 is lower than the surface hardness of the offset prevention layer 532 in the pressure roller 530, and in the nip portion N formed between the heating roller 520 and the pressure roller 530, An intermediate region located between the introduction side end and the discharge side end of the recording medium S is located closer to the heating roller 520 than the introduction side end and the discharge side end.

In the heat roll type fixing device 515 shown in FIG. 10, first, the recording medium S on which the toner image T to be fixed is formed is conveyed to the nip N between the heating roller 520 and the pressure roller 530. The toner T on the recording medium S is heated and melted by the heating roller 520 heated to a predetermined temperature by the action of the built-in heating lamp 523, and at the same time, when the toner T passes through the nip portion N, it is heated. The toner image T is fixed on the recording medium S by being pressed by the pressing force of the pressure roller 530.
Next, the recording medium S on which the toner image T is fixed passes between the heating roller 520 and the pressure roller 530 and is conveyed to a tray (not shown). At this time, the recording medium S is discharged toward the pressure roller 530, and the recording medium S is prevented from being wound around the pressure roller 530. The heating roller 520 is cleaned by a cleaning roller (not shown).

-External heating type fixing means-
FIG. 11 shows an electromagnetic induction heating type fixing device 570 showing an example of an external heating type fixing unit. The electromagnetic induction heating type fixing device 570 of FIG. 11 includes a heating roller 566, a fixing roller 580, a fixing belt 567, a pressure roller 590, and an electromagnetic induction heating unit 560.
The fixing belt 567 is stretched by a heating roller 566 and a fixing roller 580 that are rotatably arranged inside, and is heated to a predetermined temperature by the heating roller 566.
The heating roller 566 has, for example, a hollow cylindrical magnetic metal member such as iron, cobalt, nickel, or an alloy of these metals. For example, the outer diameter is 20 to 40 mm and the wall thickness is 0.3 to 1.0 mm. It has a low heat capacity and quick temperature rise.

  The fixing roller 580 has, for example, a metal core 581 made of stainless steel or the like, and the surface thereof is formed by covering a heat-resistant silicone rubber with a solid or foamed elastic layer 582. It is disposed inside the fixing belt 567 and rotatably while being in contact with the inner surface of the fixing belt 567. The fixing roller 580 is provided with an outer diameter of about 20 to 40 mm in order to form a nip portion N having a predetermined width between the pressure roller 590 and the fixing roller 580 by the pressing force from the pressure roller 590, and is heated. It is larger than the roller 566. The elastic layer 582 has a thickness of about 4 to 6 mm, and is formed so that the heat capacity of the heating roller 566 is smaller than the heat capacity of the fixing roller 580, thereby shortening the warm-up time of the heating roller 566.

  The pressure roller 590 has a metal core 591 made of a cylindrical member made of a metal having high thermal conductivity such as copper or aluminum, and the surface thereof is covered with an elastic layer 592 having high heat resistance and high toner releasability. The fixing roller 580 is in contact with the outer surface of the fixing belt 567 and the outer surface of the fixing belt 567 so as to be in pressure contact with the fixing belt 567, and is rotatably disposed. In addition to the above metal, SUS may be used for the metal core 591.

  The electromagnetic induction heating unit 560 is disposed in the vicinity of the heating roller 566 and in the axial direction of the heating roller 566. The electromagnetic induction heating unit 560 includes an excitation coil 561 that is a magnetic field generation unit, and a coil guide plate 562 around which the excitation coil 561 is wound. The coil guide plate 562 has a semi-cylindrical shape disposed close to the outer peripheral surface of the heating roller 566, and the exciting coil 561 is formed by passing a long exciting coil wire along the coil guide plate 562 in the axial direction of the heating roller 566. It is one that is wound around alternately. The exciting coil 561 is connected to a driving power source (not shown) whose frequency is variable. On the outside of the excitation coil 561, a semi-cylindrical excitation coil core 563 made of a ferromagnetic material such as ferrite is fixed to the excitation coil core support member 564 and is disposed close to the excitation coil 561.

  In the electromagnetic induction heating type fixing device 570 shown in FIG. 11, when the excitation coil 561 of the electromagnetic induction heating unit 560 is energized, an alternating magnetic field is formed around the electromagnetic induction heating unit 560, close to the excitation coil 561, and The heating roller 566 surrounded by the excitation coil 561 is preheated uniformly and efficiently by excitation of overcurrent. The recording medium S on which the toner image T to be fixed is formed is conveyed to the nip N between the fixing roller 580 and the pressure roller 590. The toner image T on the recording medium S is then heated by the fixing belt 567 heated at the contact portion W1 with the heating roller 566 by the heating roller 566 heated to a predetermined temperature by the action of the electromagnetic induction heating unit 560. It is heated and becomes a molten state. In this state, the recording medium S is inserted into a nip portion N formed between the fixing roller 580 and the pressure roller 590. The recording medium S inserted into the nip N is brought into contact with the surface of the fixing belt 567 that rotates in conjunction with the rotation of the fixing roller 580 and the pressure roller 590 and is pressed when passing through the nip N. The toner image T is fixed on the recording medium S.

  Next, the recording medium S on which the toner image T is fixed passes between the fixing roller 580 and the pressure roller 590, is peeled off from the fixing belt 567, and is conveyed to a tray (not shown). At this time, the recording medium S is discharged toward the pressure roller 590 and the winding of the recording medium S around the fixing belt 567 is prevented. The fixing belt 567 is cleaned by a cleaning roller (not shown).

12 includes a fixing roller 520 serving as the fixing member, a pressure roller 530 disposed in contact with the fixing roller 520, a fixing roller 520, and a pressure roller. The fixing unit includes an electromagnetic induction heating source 540 that heats from the outside.
The fixing roller 520 includes a cored bar 521, and the surface thereof is formed by covering a heat insulating elastic layer 522, a heat generating layer 523, and a release layer 524 in this order. The pressure roller 530 has a metal core 531, and the surface thereof is formed by covering a heat insulating elastic layer 532, a heat generating layer 533, and a release layer 534 in this order. Note that the release layer 524 and the release layer 534 are formed of tetrafluoroethylene-perfluoroalkyl vinyl ether (PFA).

The fixing roller 520 and the pressure roller 530 are urged by a spring (not shown) so as to be rotatable while being in pressure contact with each other, and form a nip portion N.
The electromagnetic induction heating source 540 is disposed in the vicinity of the fixing roller 520 and the pressure roller 530, respectively, and heats the heat generation layer 523 and the heat generation layer 533 by electromagnetic induction.
In the fixing device shown in FIG. 12, the fixing roller 520 and the pressure roller 530 are uniformly and efficiently preheated by the electromagnetic induction heating source 540. In addition, since the combination of the roller and the roller, a high surface pressure of the nip portion N can be easily realized.

<Cleaning process and cleaning means>
The cleaning step is a step of removing toner remaining on the electrostatic latent image carrier and can be suitably performed by a cleaning unit.
Further, the developing means has a developer carrier that is brought into contact with the surface of the electrostatic latent image carrier, and develops the electrostatic latent image formed on the electrostatic latent image carrier and By collecting the residual toner on the latent image carrier, cleaning can be performed without providing a cleaning means (cleaning-less method).

The cleaning means is not particularly limited, and may be selected from known cleaners as long as it can remove the toner remaining on the electrostatic latent image carrier. For example, a magnetic brush cleaner, Examples thereof include an electrostatic brush cleaner, a magnetic roller cleaner, a cleaning blade, a brush cleaner, and a web cleaner. Among these, a cleaning blade having a high toner removing ability, a small size and an inexpensive price is particularly preferable.
Examples of the material of the rubber blade used for the cleaning blade include urethane rubber, silicone rubber, fluorine rubber, chloroprene rubber, butadiene rubber, and the like. Among these, urethane rubber is particularly preferable.

  FIG. 13 is an explanatory diagram showing an enlarged view of the vicinity of the contact portion 615 with the electrostatic latent image carrier in the cleaning blade 613. The cleaning blade 613 is provided with a toner blocking surface 617 that forms a space S that expands from the contact portion 615 toward the upstream side in the rotation direction of the electrostatic latent image carrier with the surface of the photosensitive drum 1. Yes. In the present embodiment, the toner blocking surface 617 extends from the contact portion 615 to the upstream side in the rotation direction of the photosensitive drum 1 so that the space S has an acute angle.

As shown in FIG. 13, the toner blocking surface 617 is provided with a coating portion 618 as a high friction portion having a higher friction coefficient than the cleaning blade 613. The coating portion 618 is formed of a material (high friction material) having a higher friction coefficient than the material forming the cleaning blade 613. Examples of such a high friction material include DLC (diamond-like carbon). The high friction material is not limited to DLC. The coating portion 618 is provided in a range where the toner blocking surface 617 does not contact the surface of the photosensitive drum 1.
Although not shown, the cleaning unit includes a toner collection blade that collects the residual toner scraped by the cleaning blade, a toner collection coil that conveys the residual toner collected by the toner collection blade to the collection unit, and the like. ing.

-Cleaningless image forming device-
FIG. 14 is a schematic diagram illustrating an example of a cleaningless image forming apparatus in which the developing unit also serves as the cleaning unit.
In FIG. 14, 1 is a photosensitive drum as an electrostatic latent image carrier, 620 is a brush charging device as contact charging means, 603 is an exposure device as exposure means, 604 is a developing device as development means, and 640 is a supply. A paper cassette, 650 is a roller transfer means, and P is a recording medium.

  In this cleaningless image forming apparatus, the untransferred toner on the surface of the photosensitive drum 1 reaches the position of the contact charging device 620 that is in contact with the photosensitive drum 1 by the subsequent rotation of the photosensitive drum 1, and reaches the photosensitive drum 1. The toner is temporarily collected by a magnetic brush portion (not shown) of the brush charging member 621 that is in contact with the toner, and the collected toner is discharged again to the surface of the photosensitive drum 1, and finally the developer in the developing device 604. At the same time, the toner is collected by the developer carrier 631 and the photosensitive drum 1 is repeatedly used for image formation.

Here, the developing means 604 also serves as a cleaning means that the toner slightly remaining on the photosensitive drum 1 after the transfer is developed bias (between the DC voltage applied to the developer carrier 631 and the surface potential of the photosensitive drum 1). It means a method of collecting by (potential difference).
In such a cleaningless image forming apparatus in which the developing unit also serves as a cleaning unit, the transfer residual toner is collected by the developing unit 604 and is used after the next process. Therefore, the advantage in terms of space is remarkably large, and the image forming apparatus can be greatly downsized.

<Other processes and other means>
The neutralization step is a step of performing neutralization by applying a neutralization bias to the electrostatic latent image carrier, and can be suitably performed by a neutralization unit.
The neutralization means is not particularly limited, and may be appropriately selected from known neutralizers as long as it can apply a neutralization bias to the electrostatic latent image carrier. Preferably mentioned.

  The recycling step is a step of recycling the electrophotographic toner removed in the cleaning step to the developing unit, and can be suitably performed by a recycling unit. There is no restriction | limiting in particular as said recycling means, A well-known conveyance means etc. are mentioned.

The control means is a process for controlling the respective steps, and can be suitably performed by the control means.
The control means is not particularly limited as long as the movement of each means can be controlled, and can be appropriately selected according to the purpose. Examples thereof include devices such as a sequencer and a computer.

-Image forming apparatus and image forming method-
Next, one mode for carrying out the image forming method of the present invention by the image forming apparatus of the present invention will be described with reference to FIG. An image forming apparatus 100 shown in FIG. 15 includes a photosensitive drum 10 as an electrostatic latent image carrier, a charging roller 20 as a charging unit, an exposure 30 by an exposure unit as an exposure unit, and a developing unit as a developing unit. 40, an intermediate transfer member 50, a cleaning blade 60 as a cleaning means, and a static elimination lamp 70 as a static elimination means.

  The intermediate transfer member 50 is an endless belt, and is designed so as to be movable in the direction of the arrow in the figure by three rollers 51 that are arranged on the inner side and stretch the belt. Part of the three rollers 51 also functions as a transfer bias roller that can apply a predetermined transfer bias (primary transfer bias) to the intermediate transfer member 50. The intermediate transfer member 50 is provided with a cleaning blade 90 in the vicinity thereof, and the transfer capable of applying a transfer bias for transferring (secondary transfer) a visible image (toner image) to the recording medium 95. A transfer roller 80 serving as a means is arranged to face. Around the intermediate transfer member 50, a corona charger 58 for applying a charge to the toner image on the intermediate transfer member 50 is connected to the electrostatic latent image carrier 10 and the intermediate transfer member in the rotation direction of the intermediate transfer member 50. It is disposed between the contact portion with the body 50 and the contact portion between the intermediate transfer member 50 and the recording medium 95.

  The developing device 40 includes a developing belt 41 as a developer carrying member, and a black developing unit 45K, a yellow developing unit 45Y, a magenta developing unit 45M, and a cyan developing unit 45C provided around the developing belt 41. The black developing unit 45K includes a developer accommodating portion 42K, a developer supplying roller 43K, and a developing roller 44K. The yellow developing unit 45Y includes a developer accommodating portion 42Y, a developer supplying roller 43Y, and a developing roller 44Y. The magenta developing unit 45M includes a developer accommodating portion 42M, a developer supplying roller 43M, and a developing roller 44M, and the cyan developing unit 45C includes a developer accommodating portion 42C and a developer supplying roller 43C. And a developing roller 44C. Further, the developing belt 41 is an endless belt, is rotatably stretched by a plurality of belt rollers, and a part thereof is in contact with the electrostatic latent image carrier 10.

  In the image forming apparatus 100 shown in FIG. 15, for example, the charging roller 20 charges the photosensitive drum 10 uniformly. The exposure device performs imagewise exposure 30 on the photosensitive drum 10 to form an electrostatic latent image. The electrostatic latent image formed on the photosensitive drum 10 is developed by supplying toner from the developing device 40 to form a toner image. The toner image is transferred (primary transfer) onto the intermediate transfer member 50 by the voltage applied from the roller 51 and further transferred (secondary transfer) onto the recording medium 95. As a result, a transfer image is formed on the recording medium 95. The residual toner on the electrostatic latent image carrier 10 is removed by the cleaning blade 60, and the charge on the electrostatic latent image carrier 10 is once removed by the static elimination lamp 70.

  Another mode for carrying out the image forming method of the present invention by the image forming apparatus of the present invention will be described with reference to FIG. The image forming apparatus 100 shown in FIG. 16 does not include the developing belt 41 as the developer carrying member in the image forming apparatus 100 shown in FIG. 15, and the black developing unit 45 </ b> K is disposed around the electrostatic latent image carrying member 10. The yellow developing unit 45Y, the magenta developing unit 45M, and the cyan developing unit 45C are configured in the same manner as the image forming apparatus 100 shown in FIG. Show. In FIG. 16, the same components as those in FIG. 15 are denoted by the same reference numerals.

-Tandem type image forming apparatus and image forming method-
Another mode for carrying out the image forming method of the present invention by the image forming apparatus of the present invention will be described with reference to FIG. A tandem image forming apparatus 100 shown in the figure is a tandem color image forming apparatus. The tandem image forming apparatus 120 includes a copying apparatus main body 150, a paper feed table 200, a scanner 300, and an automatic document feeder (ADF) 400.

The copying apparatus main body 150 is provided with an endless belt-like intermediate transfer member 50 at the center. The intermediate transfer member 50 is stretched around the support rollers 14, 15 and 16, and can be rotated clockwise in FIG. 17. In the vicinity of the support roller 15, an intermediate transfer member cleaning unit 17 for removing residual toner on the intermediate transfer member 50 is disposed. A tandem in which four image forming units 18 of yellow, cyan, magenta, and black are arranged to face each other on the intermediate transfer member 50 stretched by the support roller 14 and the support roller 15 along the conveyance direction. A mold developing device 120 is disposed. An exposure unit 21 is disposed in the vicinity of the tandem developing device 120. On the opposite side of the intermediate transfer body 50 from the side where the tandem developing device 120 is arranged, the secondary transfer means 22 is arranged. In the secondary transfer unit 22, a secondary transfer belt 24 that is an endless belt is stretched around a pair of rollers 23, and the recording medium conveyed on the secondary transfer belt 24 and the intermediate transfer member 50 are in contact with each other. Is possible. A fixing unit 25 is disposed in the vicinity of the secondary transfer unit 22.
In the tandem image forming apparatus 100, a reversing device 28 for reversing the recording medium in order to form an image on both sides of the recording medium is disposed in the vicinity of the secondary transfer unit 22 and the fixing unit 25. .

Next, formation of a full-color image (color copy) using the tandem developing device 120 will be described. That is, first, a document is set on the document table 130 of the automatic document feeder (ADF) 400, or the automatic document feeder 400 is opened and the document is set on the contact glass 32 of the scanner 300. 400 is closed.
When a start switch (not shown) is pressed, when a document is set on the automatic document feeder 400, the document is transported and moved onto the contact glass 32, and then the document is set on the contact glass 32. Immediately after that, the scanner 300 is driven, and the first traveling body 33 and the second traveling body 34 travel. At this time, light from the light source is emitted from the first traveling body 33 and reflected light from the document surface is reflected by the mirror in the second traveling body 34 and is received by the reading sensor 36 through the imaging lens 35 to be color. An original (color image) is read and used as black, yellow, magenta, and cyan image information.

  Each image information of black, yellow, magenta and cyan is stored in each image forming unit 18 (black image forming unit, yellow image forming unit, magenta image forming unit, and cyan image forming unit) in the tandem type developing device 120. Each image forming unit forms black, yellow, magenta, and cyan toner images. That is, each image forming means 18 (black image forming means, yellow image forming means, magenta image forming means, and cyan image forming means) in the tandem developing device 120 is a static image as shown in FIG. An electrostatic latent image carrier 10 (black electrostatic latent image carrier 10K, yellow electrostatic latent image carrier 10Y, magenta electrostatic latent image carrier 10M, and cyan electrostatic latent image carrier 10C); A charger 60 that uniformly charges the electrostatic latent image carrier, and the electrostatic latent image carrier is exposed like an image corresponding to each color image based on each color image information (L in FIG. 18). An exposure device for forming an electrostatic latent image corresponding to each color image on the electrostatic latent image carrier, and each color toner (black toner, yellow toner, magenta toner, and cyan toner) for the electrostatic latent image. Use and develop each A developer 61 for forming a toner image with toner, a transfer charger 62 for transferring the toner image onto the intermediate transfer member 50, a cleaning means 63, and a static eliminator 64. Each monochrome image (black image, yellow image, magenta image, and cyan image) can be formed based on the image information. The black image, the yellow image, the magenta image, and the cyan image formed in this manner are respectively transferred to the black electrostatic latent image carrier 10K on the intermediate transfer member 50 that is rotationally moved by the support rollers 14, 15 and 16. Black image formed on top, yellow image formed on electrostatic latent image carrier 10Y for yellow, magenta image formed on electrostatic latent image carrier 10M for magenta, and electrostatic latent image carrier for cyan The cyan image formed on 10C is sequentially transferred (primary transfer). Then, the black image, the yellow image, the magenta image, and the cyan image are superimposed on the intermediate transfer member 50 to form a composite color image (color transfer image).

  On the other hand, in the paper feed table 200, one of the paper feed rollers 142 is selectively rotated to feed the recording medium from one of the paper feed cassettes 144 provided in multiple stages in the paper bank 143, and one sheet at a time by the separation roller 145. The paper is separated and sent to the paper feed path 146, transported by the transport roller 147, guided to the paper feed path 148 in the copying machine main body 150, and abutted against the registration roller 49 to stop. Alternatively, the recording roller 142 is rotated to feed out the recording medium on the manual feed tray 54, separated one by one by the separation roller 52, put into the manual feed path 53, and abutted against the registration roller 49 and stopped. The registration roller 49 is generally used while being grounded, but may be used in a state where a bias is applied to remove paper dust from the recording medium. Then, the registration roller 49 is rotated in synchronization with the synthesized color image (color transfer image) synthesized on the intermediate transfer member 50, and the recording medium is sent between the intermediate transfer member 50 and the secondary transfer means 22. Then, by transferring (secondary transfer) the composite color image (color transfer image) onto the recording medium by the secondary transfer means 22, a color image is transferred and formed on the recording medium. The residual toner on the intermediate transfer member 50 after image transfer is cleaned by the intermediate transfer member cleaning means 17.

  The recording medium on which the color image has been transferred is conveyed by the secondary transfer means 22 and sent to the fixing means 25, where the combined color image (color transfer image) is generated by heat and pressure. Is fixed on the recording medium. After that, the recording medium is switched by the switching claw 55 and discharged by the discharge roller 56 and stacked on the paper discharge tray 57. Alternatively, the recording medium is switched by the switching claw 55 and reversed by the reversing device 28 and led again to the transfer position. After the image is also recorded on the back surface, the image is discharged by the discharge roller 56 and stacked on the discharge tray 57.

<Process cartridge>
The toner developer of the present invention is easy to store and transport, has excellent handleability, and is preferably used for replenishing toner by being detachably attached to the process cartridge and image forming apparatus of the present invention described later. Can do.
The process cartridge of the present invention can be mounted on an image liquid apparatus, and includes an electrostatic latent image carrier that carries an electrostatic latent image, and an electrostatic latent image carried on the electrostatic latent image carrier. A developing unit that develops with a developer to form a visible image, and further selected appropriately according to need, a charging unit, an exposure unit, a developing unit, a transfer unit, a cleaning unit, a static elimination unit. It has other means such as means.
The developing means includes at least a developer container that contains the developer of the present invention and an electrostatic latent image carrier that carries and conveys the developer contained in the developer container. Further, a layer thickness regulating member for regulating the thickness of the toner layer to be carried may be provided.
The process cartridge of the present invention can be detachably provided in various electrophotographic apparatuses, facsimiles, and printers, and is preferably provided detachably in an image forming apparatus described later.

Here, for example, as shown in FIG. 19, the process cartridge includes a photosensitive member 101, and further includes a charging unit 102, a developing unit 104, and a cleaning unit 107, and further includes other members as necessary. Do it. The process cartridge example of FIG. 1 has a transfer means 108 for transferring the developed toner image on the photoreceptor 101 to the image receiving paper 105.
As the photoreceptor 101, the above-described one can be used.
A light source capable of writing with high resolution is used for the exposure means 103.
An arbitrary charging member is used for the charging unit 102.

Hereinafter, the present invention will be further described with reference to examples, but the present invention is not limited thereto.
In the following, “part” means part by mass, and “%” means mass%.

<Measurement method>
[Softening point of resin]
Using a flow tester (Shimadzu Corporation, CFT-500D), while applying 1 g of sample resin at a heating rate of 3 ° C./min, a load of 0.98 MPa was applied by a plunger and extruded from a nozzle with a diameter of 1 mm and a length of 1 mm. To do. The plunger drop amount of the flow tester is plotted against the temperature, and the temperature at which half of the sample flows out is taken as the softening point of the resin.

[Glass transition point of resin]
Using a differential scanning calorimeter (Seiko Denshi Kogyo Co., Ltd., DSC210), 0.005 g of sample resin is weighed into an aluminum pan, heated to 200 ° C., and cooled from that temperature to 0 ° C. at a cooling rate of 10 ° C./min. The sample was heated at a heating rate of 10 ° C / min, and the temperature at the intersection of the base line extension below the endothermic peak temperature and the tangent indicating the maximum slope from the peak rise to the peak apex The glass transition point of

[Melting point of wax]
Using a differential scanning calorimeter (Seiko Denshi Kogyo Co., Ltd., DSC210), 0.005 g of sample wax was weighed into an aluminum pan, heated to 200 ° C., and cooled to 0 ° C. at a cooling rate of 10 ° C./min. The endothermic peak temperature when the sample was heated at a heating rate of 10 ° C./min is defined as the melting point of the wax.

<Examples of polyester resin synthesis>
Put the alcohol component shown in Table 1, the carboxylic acid component other than trimellitic anhydride, and the esterification catalyst into a 5-liter four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer, and a thermocouple. Then, after performing a condensation polymerization reaction at 230 ° C. for 10 hours, the reaction was performed at 230 ° C. and 8.0 kPa for 1 hour. After cooling to 220 ° C., trimellitic anhydride is added, and after reacting at normal pressure for 1 hour, the reaction is carried out at 220 ° C. and 20 kPa until a desired softening point is reached. Obtained.

<Example of toner production>
Binder resin, pigment, release agent, and charge control agent are charged into a Henschel mixer “MF20C / I type” (Mitsui Miike Processing Co., Ltd.), mixing conditions: 1500 rpm, 5 cycles, 60 seconds for 1 cycle. After stirring, the mixture was stopped for 60 seconds and sufficiently mixed with stirring, then kneaded with a twin screw extruder (manufactured by Toshiba Machine Co., Ltd.) and cooled on a steel belt. Here, the kneading was performed such that the temperature of the kneaded product at the exit of the twin-screw extruder was around 120 ° C. Next, the toner base was prepared by pulverizing with a jet mill so that the mass average particle diameter was 6.0 ± 0.5 μm, followed by air classification. To 100 parts by mass of the obtained powder, 1.0 part by mass of “silica: HDK H 2000” (manufactured by Clariant Japan) and “titanium oxide: JMT-150IB” (manufactured by Teika) are added as external additives. The toner was obtained by mixing with a Henschel mixer.

  In addition, in order to measure the electrification of particles without external additives and release agents, a binder resin, a pigment, and a charge control agent were charged into a Henschel mixer “MF20C / I type” (manufactured by Mitsui Miike Processing Co., Ltd.) Mixing conditions: 1500 rpm, 5 cycles, stirring in 60 seconds, stopping for 60 seconds, mixing with sufficient stirring, kneading with a twin screw extruder (manufactured by Toshiba Machine), cooling on steel belt did. The kneading was performed by setting the temperature of the kneaded product at the outlet of the twin-screw extruder to be around 120 ° C. Next, the mixture was pulverized with a jet mill so that the mass average particle diameter became 6.0 ± 0.5 μm, and then subjected to air classification to produce particles without external additives and without release agents.

<Example 1>
Four color toners were prepared according to the above toner production example with the following formulation.
(Black toner)
Resin 1 70 parts Resin 2 30 parts Pigment (carbon black) 5 parts Release agent (glycerin, stearic acid, ester) 5 parts Charge control agent: Bontron E-84 (Orient Chemical Industries) 0.5 part

(Yellow toner)
Resin 1 70 parts Resin 2 30 parts Pigment (CI Pigment Yellow 74) 5 parts Release agent (glycerin, stearic acid, ester) 5 parts Charge control agent: Bontron E-84 (Orient Chemical Industries) 0.5 Part

(Magenta toner)
Resin 1 70 parts Resin 2 30 parts Pigment (CI Pigment Red 269) 8 parts Release agent (glycerin, stearic acid, ester) 5 parts Charge control agent: Bontron E-84 (Orient Chemical Industries) 0.5 Part

(Black toner)
Resin 1 70 parts Resin 2 30 parts Pigment (CI Pigment Red 15-3) 5 parts Release agent (glycerin, stearic acid, ester) 5 parts Charge control agent: Bontron E-84 (Orient Chemical Industries) 0 .5 parts

<Examples 2-12, Comparative Examples 1-3>
In Examples 2 to 11 and Comparative Examples 1 to 3, toners were prepared in the same manner as in Example 1 except that the release agent was as shown in Table 2 and the other resins, pigments, and charge control agents were the same as in Example 1. In Example 12, a toner was prepared from Example 1 except for the charge control agent: Bontron E-84 (Orient Chemical Industries).

<Example of carrier production>
The raw materials shown below were dispersed with a homomixer for 10 minutes to obtain a blend coating film forming solution of an acrylic resin and a silicone resin containing alumina particles. A fired ferrite powder [(MgO) _2.5 (MnO) _49.5 (Fe ₂ O ₃ ) _48.0 : average particle size; 50 μm] was used as the core material, and the coating film forming solution was formed on the surface of the core material. It was applied with a Spira coater (manufactured by Okada Seiko Co., Ltd.) to a thickness of 0.15 μm and dried. The obtained carrier was baked by standing in an electric furnace at 150 ° C. for 1 hour. After cooling, the ferrite powder bulk was crushed using a sieve having an opening of 106 μm to obtain a carrier.

Acrylic resin solution (solid content 50 wt%) 21.0 parts Guanamin solution (solid content 70 wt%) 6.4 parts Alumina particles [0.3 μm, specific resistance 1014 (Ω · cm)] 7.6 parts Silicone resin solution [solid 23wt% min
(SR2410: manufactured by Toray Dow Corning Silicone Co., Ltd.)] 65.0 parts aminosilane [solid content: 100 wt%
(SH6020: manufactured by Toray Dow Corning Silicone Co., Ltd.)] 0.3 parts Toluene 60 parts Butyl cellosolve 60 parts

<Developer>
6 parts by mass of the toner and 94 parts by mass of the carrier were stirred for 5 minutes with a tumbler mixer (Willy A. Bachofen AG Machinenfabrik T2F) to prepare a developer.

<Evaluation>
Table 3 shows the charge amounts of the carrier, the toner of the example, the toner without the external additive, and the toner without the external additive and the release agent.

The developer of the above example was put in Ricoh's digital color imagio Neo C455 for evaluation. The image formation was adjusted so that the adhesion amount was about 0.5 mg / cm ^{2 for} each color.
<Confirmation of fixing hot offset resistance>
The maximum temperature at which hot offset does not occur was measured by changing the temperature of the fixing belt. The fixing belt temperature was swung in increments of 5 ° C., only black toner was imaged, and it was visually confirmed whether hot offset had occurred. Note that the cleaning roller of the fixing belt was removed during this evaluation so that the hot offset could be confirmed. The results are shown in Table 4.

<Long-term running> Image area ratio: 10% of each color (total 40%), A4, 100,000 sheets were output and compared with the initial state. The background fogging of the image was evaluated. The fog was evaluated by measuring the image density of the background portion of the output image with X-Rite 938 manufactured by X-Rite, and subtracting the image density of the paper before output. The measurement conditions were status A and the measured value of V was used. Further, the charge amount of the toner was measured using the carrier in the developer after outputting 100,000 sheets. The carrier used in the developer was obtained by placing the developer on a sieve having an opening of 20 μm, and sucking the toner in the developer cleanly with a vacuum cleaner. The results are shown in Table 5.

  Compared with the toner of the comparative example, the toner of the present invention does not decrease the charge amount of the carrier and does not increase the background fog even when running for a long time. Also, the hot offset resistance to fixing is good.

FIG. 3 is a schematic cross-sectional view illustrating an example of a charging roller in the image forming apparatus of the present invention. 1 is a schematic diagram illustrating an example in which a contact-type charging roller in an image forming apparatus of the present invention is applied to an image forming apparatus. 1 is a schematic diagram illustrating an example in which a non-contact type corona charger in an image forming apparatus of the present invention is applied to an image forming apparatus. FIG. 2 is a schematic diagram illustrating an example of a non-contact charging roller in the image forming apparatus of the present invention. FIG. 2 is a schematic diagram illustrating an example of a one-component developing unit in the image forming apparatus of the present invention. FIG. 2 is a schematic diagram illustrating an example of a two-component developing unit in the image forming apparatus of the present invention. 1 is a schematic diagram illustrating an example of a direct transfer method of a tandem type image forming apparatus of the present invention. FIG. 3 is a schematic diagram illustrating an example of an indirect transfer method of the tandem type image forming apparatus of the present invention. FIG. 3 is a schematic diagram illustrating an example of a belt-type fixing unit in the image forming apparatus of the present invention. FIG. 3 is a schematic diagram illustrating an example of a heat roller type fixing unit in the image forming apparatus of the present invention. FIG. 3 is a schematic diagram illustrating an example of an electromagnetic induction heating type fixing unit in the image forming apparatus of the present invention. FIG. 5 is a schematic diagram illustrating another example of an electromagnetic induction heating type fixing unit in the image forming apparatus of the present invention. FIG. 3 is a schematic diagram illustrating an example of a cleaning blade in the image forming apparatus of the present invention. 1 is a schematic diagram illustrating an example of a cleaningless type image forming apparatus in an image forming apparatus of the present invention. 1 is a schematic diagram illustrating an example of an image forming apparatus of the present invention. It is the schematic which shows another example of the image forming apparatus of this invention. 1 is a schematic diagram illustrating an example of a tandem type image forming apparatus of the present invention. FIG. 18 is an enlarged view of each image forming element in FIG. 17. It is the schematic which shows an example of the process cartridge of this invention.

Explanation of symbols

1 Electrostatic latent image carrier (photosensitive drum)
2 Transfer means 3 Conveyor belt 4 Intermediate transfer body 5 Secondary transfer means 6 Paper feeder 7 Fixing means 8 Cleaning means 9 Intermediate transfer body cleaning means 10 Electrostatic latent image carrier (photosensitive drum)
10K Electrostatic latent image carrier for black 10Y Electrostatic latent image carrier for yellow 10M Electrostatic latent image carrier for magenta 10C Electrostatic latent image carrier for cyan 14 Support roller 15 Support roller 16 Support roller 17 Intermediate transfer cleaning means DESCRIPTION OF SYMBOLS 18 Image forming means 20 Charging roller 21 Exposure means 22 Secondary transfer means 23 Roller 24 Secondary transfer belt 25 Fixing means 26 Fixing belt 27 Pressure roller 28 Reversing device 30 Exposure means 32 Contact glass 33 First traveling body 34 Second traveling Body 35 Imaging lens 36 Reading sensor 40 Developer 41 Developing belt 42K Developer container 42Y Developer container 42M Developer container 42C Developer container 43K Developer supply roller 43Y Developer supply roller 43M Developer supply roller 43C Developer supply roller 44K Development roller 44 Y development roller 44M development roller 44C development roller 45K black development unit 45Y yellow development unit 45M magenta development unit 45C cyan development unit 49 registration roller 50 intermediate transfer member 51 roller 52 separation roller 53 manual feed path 54 manual feed tray 55 Switching claw 56 Discharge roller 57 Discharge tray 58 Corona charger 60 Cleaning means 61 Developer 62 Transfer charger 63 Cleaning means 64 Charger 70 Charger lamp 80 Transfer roller 90 Cleaning means 95 Recording medium 100 Image forming apparatus 101 Electrostatic latent image carrier Body 102 Charging means 103 Exposure means 104 Developing means 105 Recording medium 107 Cleaning means 108 Transfer means 120 Tandem developer 130 Document table 142 Feed roller 143 Paper bank 144 Feed Cassette 145 Separating roller 146 Feeding path 147 Conveying roller 148 Feeding path 150 Copier main body 200 Feeding table 220 Heating roller 230 Pressure roller 300 Scanner 302 Film 303 Spring 310 Charging roller 311 Core metal 312 Resistance adjustment layer 313 Protective layer 314 Corona charger 321 Electrostatic latent image carrier 323 Exposure means 324 Development means 325 Transfer means 326 Recording medium 327 Fixing means 330 Cleaning means 331 Charger 400 Automatic document feeder (ADF)
401 casing 402 developing roller 411 agitator 412 supply roller 413 regulating blade 510 belt type fixing device 511 heating roller 512 fixing roller 513 fixing belt 514 pressure roller 515 heat roll type fixing device 525 roll type fixing device 570 electromagnetic induction heating type fixing device 613 Cleaning blade S Recording medium P Recording medium

Claims (13)

In an electrophotographic developer having a toner and a carrier containing at least a release agent, a binder resin, a colorant, and an external additive, the relationship between the toner and the carrier is the following (1) and (2) An electrophotographic developer characterized by satisfying the following conditions.
(1) The triboelectric charge generated between the toner and the carrier and the triboelectric charge generated between the toner particles before the external additive is attached to the toner and the carrier are oppositely charged. There is.
(2) Frictional charge generated between the toner and the carrier, and friction generated between the toner particles and the carrier in a state in which the release agent is removed from the toner and before the external additive is attached. Charge is the same polarity charge.   The electrophotographic developer according to claim 1, wherein at least glycerin fatty acid ester or polyglycerin fatty acid ester is used as the release agent.   The developer for electrophotography according to claim 2, wherein the hydroxyl value of the glycerin fatty acid ester or the polyglycerin fatty acid ester is 0 to 100 mgKOH / g.   4. The electrophotographic developer according to claim 2, wherein stearic acid or behenic acid, or both stearic acid and behenic acid are used as fatty acids of glycerin fatty acid ester or polyglycerin fatty acid ester.   The electrophotographic developer according to claim 2, wherein the toner is a negatively chargeable toner.   The developer for electrophotography according to any one of claims 1 to 5, wherein at least silica and titanium oxide are used as external additives.   The electrophotographic developer according to claim 1, wherein the release agent is contained in the toner in an amount of 1 to 10% by mass.   The electrophotographic developer according to claim 1, wherein at least a polyester resin is used as the binder resin.   The electrophotographic developer according to claim 1, wherein a yellow colorant is used as the colorant.   The electrophotographic developer according to claim 1, wherein a magenta colorant is used as the colorant.   The electrophotographic developer according to claim 1, wherein a cyan colorant is used as the colorant.   The developer for electrophotography according to any one of claims 1 to 8, wherein a black colorant is used as the colorant.   An electrostatic latent image carrier that can be mounted on an image forming apparatus and an electrostatic latent image formed on the electrostatic latent image carrier using the electrophotographic developer according to claim 1. A process cartridge having at least developing means for developing and forming a visible image.

Images