JP5880349B2 - Liquid developer, developer cartridge, process cartridge, image forming apparatus and image forming method - Google Patents

Description

  The present invention relates to a liquid developer, a developer cartridge, a process cartridge, an image forming apparatus, and an image forming method.

  A method of visualizing image information through an electrostatic charge image such as electrophotography is currently used in various fields. In electrophotography, a latent image (electrostatic latent image) is formed on an image carrier by a charging and exposure process (latent image forming process), and an electrostatic charge image developing toner (hereinafter simply referred to as “toner”). The electrostatic latent image is developed (development process) with a developer for developing electrostatic images (hereinafter sometimes referred to simply as “developer”), and visualized through a transfer process and a fixing process. The Developers used in the dry development method include a two-component developer composed of a toner and a carrier, and a one-component developer using a magnetic toner or a non-magnetic toner alone.

  On the other hand, the liquid developer used in the wet development system is one in which toner particles are dispersed in an insulating carrier liquid, and a type in which toner particles containing a thermoplastic resin are dispersed in a volatile carrier liquid. A type in which toner particles containing a thermoplastic resin are dispersed in a hardly volatile carrier liquid is known.

  For example, in Patent Document 1, in a liquid developer for electrophotography in which a toner mainly composed of a colorant and a resin is dispersed in a highly insulating carrier liquid mainly composed of silicon, the resin is soluble in the carrier liquid. An electrophotographic liquid developer comprising a combination of the above resin and a resin insoluble in the carrier liquid and containing an organic compound containing any one of a divalent to tetravalent metal as a charge adjusting agent is described.

  In Patent Document 2, in a dispersion composition obtained by dispersing a particulate material in an organic solvent such as a silicone-based organic solvent, 0.01 μm self-dispersed in the organic solvent is formed on at least a part of the outer surface of the particulate material. A dispersion composition in which an acrylic polymer compound having an average particle diameter in the range of ˜1 μm is adsorbed is described.

  Patent Document 3 discloses a modified silicone containing toner particles, an insulating carrier liquid such as silicone oil, and at least one functional group selected from mercapto groups or alkoxy groups added to the insulating carrier liquid. And a liquid developer composed of carbon black having a pH of 4 or less.

  Patent Document 4 discloses toner particles obtained by chemically modifying, using an epoxy-modified silicone, colored particles containing a binder resin and a colorant in an electrically insulating liquid such as silicone oil and having acidic groups on the surface. Including liquid developing toners.

  Patent Document 5 describes a liquid developer containing toner particles whose surface is modified with polyalkyleneimine and an insulating liquid composed of a hydrogen-modified silicone compound.

  Patent Document 6 discloses a toner in which a liquid carrier containing silicone oil as a main component includes at least a resin and a color pigment, and the resin molecule includes a functional group having hydrogen bonding ability with water molecules. Dispersed liquid developers are described.

  Patent Document 7 describes a liquid developer containing a dispersion promoting substance such as a methyl methacrylate compound having either a carboxyl group or a hydroxyl group as a dispersion promoting substance for promoting dispersion of colored particles in silicone oil. Has been.

Japanese Patent Laid-Open No. 06-214431 JP 2001-098206 A JP 2005-115244 A JP 2009-288414 A JP 2010-224300 A JP 2004-157427 A JP 2004-302436 A

  An object of the present invention is to provide a low-viscosity liquid developer, a developer cartridge using the liquid developer, a process cartridge, an image forming apparatus, and an image forming method.

  The invention according to claim 1 is a liquid developer containing a carrier liquid containing a silicone oil, toner particles containing a polyester resin, and a reaction product of an amino-modified silicone oil and an epoxy compound.

（１）
（式（１）中、Ｘ、ＹおよびＺは、それぞれ独立してメチル基、−Ｒ^１ＮＨ_２またはＲ^２ＮＨＲ^３ＮＨ_２を示し、かつＸ、ＹおよびＺのうち少なくとも一つは、−Ｒ^１ＮＨ_２またはＲ^２ＮＨＲ^３ＮＨ_２を示す。Ｘ、Ｙのいずれかもしくは両方が−Ｒ^１ＮＨ_２またはＲ^２ＮＨＲ^３ＮＨ_２である場合、ｍは、１以上１００以下の整数を示し、ｎは、０以上１００以下の整数を示し、Ｘ、Ｙのいずれも−Ｒ^１ＮＨ_２またはＲ^２ＮＨＲ^３ＮＨ_２ではない場合、ｍは、０以上１００以下の整数を示し、ｎは、１以上１００以下の整数を示す。Ｒ^１、Ｒ^２およびＲ^３は、それぞれ独立して炭素数１以上８以下の２価のアルキル基を示す。）

（２）
（式（２）中、Ｒ^４は、水素原子、アルキル基またはアルキルアルコール基を示す。） In the invention according to claim 2, the silicone oil is dimethyl silicone, the amino-modified silicone oil is a compound represented by the following general formula (1), and the epoxy compound is represented by the following general formula (2). The liquid developer according to claim 1, wherein

(1)
(In the formula (1), X, Y and Z each independently represent a methyl group, —R ¹ NH ₂ or R ² NHR ³ NH ₂ , and at least one of X, Y and Z is — R ¹ NH ₂ or R ² NHR ³ NH _{2 When} either or both of X and Y are —R ¹ NH ₂ or R ² NHR ³ NH ₂ , m represents an integer of 1 or more and 100 or less. , N represents an integer of 0 to 100, and when X and Y are not —R ¹ NH ₂ or R ² NHR ³ NH ₂ , m represents an integer of 0 to 100, and n is And represents an integer of 1 to 100. R ¹ , R ² and R ³ each independently represents a divalent alkyl group having 1 to 8 carbon atoms.

(2)
(In formula (2), R ⁴ represents a hydrogen atom, an alkyl group or an alkyl alcohol group.)

  A third aspect of the present invention is a developer cartridge in which the liquid developer according to the first or second aspect is accommodated.

  The invention according to claim 4 is a process cartridge in which the liquid developer according to claim 1 or 2 is accommodated.

  According to a fifth aspect of the present invention, there is provided an image carrier, a latent image forming unit that forms a latent image on the surface of the image carrier, and the latent image formed on the surface of the image carrier. A developing means for forming a toner image by developing the liquid developer according to claim 1 held on the surface of the toner image, and transferring the toner image formed on the surface of the image carrier onto a recording medium And a fixing unit that fixes the toner image transferred to the recording medium to the recording medium to form a fixed image.

  According to a sixth aspect of the present invention, the latent image forming step of forming a latent image on the surface of the image holding member and the latent image formed on the surface of the image holding member are held on the surface of the developer holding member. A development step of developing with the liquid developer according to claim 1 to form a toner image, a transfer step of transferring the toner image formed on the surface of the image carrier onto a recording medium, A fixing step of fixing the toner image transferred to the recording medium to the recording medium to form a fixed image.

  According to the first aspect of the present invention, a liquid developer having a low viscosity is provided as compared with the case of containing only the amino-modified silicone oil.

  According to the invention which concerns on Claim 2, compared with the case where the said amino modification silicone oil is a compound shown by the said General formula (1), and the said epoxy compound is not a compound shown by the said General formula (2), low viscosity A liquid developer is provided.

  According to the third aspect of the present invention, there is provided a developer cartridge that contains a liquid developer having a low viscosity as compared with the case where the liquid developer contains only amino-modified silicone oil.

  According to the invention which concerns on Claim 4, compared with the case where a liquid developer contains only an amino modified silicone oil, the process cartridge in which the low viscosity liquid developer is accommodated is provided.

  According to the fifth aspect of the present invention, there is provided an image forming apparatus using a liquid developer having a low viscosity as compared with a case where the liquid developer contains only an amino-modified silicone oil.

  According to the invention of claim 6, there is provided an image forming method using a liquid developer having a low viscosity as compared with the case where the liquid developer contains only an amino-modified silicone oil.

1 is a schematic configuration diagram illustrating an example of an image forming apparatus according to an embodiment of the present invention.

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

<Liquid developer>
The liquid developer according to this embodiment contains a carrier liquid containing silicone oil, toner particles containing a polyester resin, and a reaction product of an amino-modified silicone oil and an epoxy compound.

In a liquid developer, toner particles are dispersed in oil as a carrier liquid, and a highly insulating paraffin oil or the like is often used as the carrier liquid. As the dispersed toner particles, it is possible to use particles containing styrene-acrylic resin or polyester resin as used in toners used in ordinary dry developers, but they are carrier liquids. Plasticization is caused by the paraffin oil, and in particular, when the oil remains in the toner particles, the storage stability of the obtained image may be inferior. The inventors have
As a combination of toner particles and carrier liquid for improving image storage stability, the use of silicone oil as the carrier liquid and the use of particles containing a polyester resin as the toner particles was investigated. Silicone oil can disperse polyester particles. However, when the toner particles in the liquid developer increase in concentration, the viscosity increases, which may clog the piping of image forming apparatuses and make handling difficult. It was.
When trying to make the liquid developer within a usable viscosity range, the obtained image quality was inferior. This tendency was particularly noticeable when toner particles having a small particle diameter were used to improve the image quality. In particular, when toner particles having a small particle diameter are used, a technique for adjusting the viscosity of the liquid developer is desired in order to obtain a liquid developer that can prevent clogging of piping and can be easily handled. The present inventors have developed a low-viscosity liquid development by using toner particles containing a polyester resin and a carrier liquid containing a silicone oil, and further using a reaction product of an amino-modified silicone oil and an epoxy compound as an additive. It was found that an agent can be obtained.

  By having an amino group in the structure of the silicone oil, the adsorptivity to the toner particles containing the polyester resin is improved. However, since the amino group has a high polarity, the solubility in the silicone oil is low. In order to increase the solubility of the amino-modified silicone in silicone oil, it is conceivable to make the primary amine of the amino group of the amino-modified silicone have a structure having a large steric hindrance. We investigated alkylation by ring-opening addition reaction with a group. Furthermore, in this reaction, it is possible to introduce an alkyl group into the produced amino-modified silicone, and this effect is considered to further promote the adsorption to the toner particles and reduce the viscosity with a small addition amount.

  Hereinafter, the components of the liquid developer according to this embodiment will be described in detail.

  A reaction product of an amino-modified silicone oil and an epoxy compound (hereinafter sometimes referred to as “amino-modified silicone / epoxy reaction product”) is obtained by reacting a general amino-modified silicone with a low molecular weight organic epoxy compound. It is.

  The amino-modified silicone oil may be a side chain type compound, a single-end compound, a double-end compound, or a mixture thereof. The amino-modified functional group may be a primary amine, a monoamine of a secondary amine, or a diamine, but diamine is particularly preferable as the reactivity with the organic epoxy compound and the structure after the reaction.

（１）
（式（１）中、Ｘ、ＹおよびＺは、それぞれ独立してメチル基、−Ｒ^１ＮＨ_２またはＲ^２ＮＨＲ^３ＮＨ_２を示し、かつＸ、ＹおよびＺのうち少なくとも一つは、−Ｒ^１ＮＨ_２またはＲ^２ＮＨＲ^３ＮＨ_２を示す。Ｘ、Ｙのいずれかもしくは両方が−Ｒ^１ＮＨ_２またはＲ^２ＮＨＲ^３ＮＨ_２である場合、ｍは、１以上１００以下の整数を示し、ｎは、０以上１００以下の整数を示し、Ｘ、Ｙのいずれも−Ｒ^１ＮＨ_２またはＲ^２ＮＨＲ^３ＮＨ_２ではない場合、ｍは、０以上１００以下の整数を示し、ｎは、１以上１００以下の整数を示す。Ｒ^１、Ｒ^２およびＲ^３は、それぞれ独立して炭素数１以上８以下の２価のアルキル基を示す。） The amino-modified silicone oil is, for example, a compound represented by the following general formula (1).

(1)
(In the formula (1), X, Y and Z each independently represent a methyl group, —R ¹ NH ₂ or R ² NHR ³ NH ₂ , and at least one of X, Y and Z is — R ¹ NH ₂ or R ² NHR ³ NH _{2 When} either or both of X and Y are —R ¹ NH ₂ or R ² NHR ³ NH ₂ , m represents an integer of 1 or more and 100 or less. , N represents an integer of 0 to 100, and when X and Y are not —R ¹ NH ₂ or R ² NHR ³ NH ₂ , m represents an integer of 0 to 100, and n is And represents an integer of 1 to 100. R ¹ , R ² and R ³ each independently represents a divalent alkyl group having 1 to 8 carbon atoms.

In formula (1), even if one of X and Y is —R ¹ NH ₂ or R ² NHR ³ NH ₂ (one-end compound), Z is —R ¹ NH ₂ or R ² NHR ³ NH ₂ Even if (side chain type compound), X and Y may be -R ¹ NH ₂ or R ² NHR ³ NH ₂ (both end compounds), but from the viewpoint of stability of the compound, etc. Is preferred.

In the formula (1), R ¹ , R ² and R ³ are divalent alkyl groups having 1 to 8 carbon atoms, preferably divalent alkyl groups having 1 to 4 carbon atoms. Examples of the divalent alkyl group having 1 to 8 carbon atoms include a methylene group, an ethylene group, and a propylene group, and a methylene group, an ethylene group, and a propylene group are preferable from the viewpoint of compatibility with silicone oil.

  In Formula (1), in the case of a side chain compound, m is an integer of 0 to 100, and preferably an integer of 0 to 70. m is an integer of 1 or more and 100 or less, and preferably an integer of 10 or more and 70 or less in the case of a compound at one or both ends. In the formula (1), n is an integer of 1 to 100, preferably an integer of 1 to 40, and more preferably an integer of 1 to 10 in the case of a side chain compound. n is an integer of 0 or more and 100 or less, preferably an integer of 0 or more and 40 or less, and more preferably an integer of 0 or more and 10 or less in the case of one-end or both-end compounds.

  Specific examples of the amino-modified silicone oil include commercially available products KF-868, KF-865, KF-864, KF-859, KF-393, KF-860, KF-880, KF- manufactured by Shin-Etsu Silicone. 8004, KF-8002, KF-8005, KF-867, KF-869, KF-861, KF-857, KF-8001, KF-862, X22-3820W, X22-3939A, X22-9192, and the like.

  The epoxy compound is an organic epoxy compound having a low molecular weight and is not limited to this as long as it has at least one epoxy group in its structure. A monoepoxy compound is preferred. Moreover, it is preferable to have an alkyl group or an alkyl alcohol group in the structure of an epoxy compound. This structure further improves the solubility of the amino-modified silicone / epoxy reactant produced in the silicone oil.

（２）
（式（２）中、Ｒ^４は、水素原子、アルキル基またはアルキルアルコール基を示す。） The epoxy compound is, for example, a compound represented by the following general formula (2).

(2)
(In formula (2), R ⁴ represents a hydrogen atom, an alkyl group or an alkyl alcohol group.)

In the formula (2), R ⁴ is, for example, a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an alkyl alcohol group having 1 to 20 carbon atoms. Examples of the alkyl group having 1 to 20 carbon atoms include a methyl group, an ethyl group, a linear or branched propyl group, and a butyl group. From the viewpoint of stability of the compound, a methyl group, an ethyl group, and a propyl group A butyl group is preferred. Examples of the alkyl alcohol group having 1 to 20 carbon atoms include a hydroxymethyl group, a hydroxyethyl group, a hydroxypropyl group, and the like. From the viewpoint of stability of the compound, a hydroxyethyl group and a hydroxypropyl group are preferable.

  Specific examples of the amino-modified silicone / epoxy reactant include commercially available products such as KF-877 manufactured by Shin-Etsu Silicone.

  The amount of the amino-modified silicone / epoxy reactant in the liquid developer is, for example, preferably in the range of 0.001 to 10 parts by mass with respect to 100 parts by mass of the liquid developer, 0.01 parts by mass More preferably, it is in the range of 1 part by mass or less. When the amount of the amino-modified silicone / epoxy reactant with respect to the liquid developer is less than 0.001 part by mass with respect to 100 parts by mass of the liquid developer, the viscosity reduction may be insufficient, and when it exceeds 10 parts by mass, The conductivity may increase.

  The weight average molecular weight of the amino-modified silicone / epoxy reactant is preferably in the range of 500 to 10,000, and more preferably in the range of 1,000 to 5,000. If the weight average molecular weight of the amino-modified silicone / epoxy reactant is less than 500, the polarity may be too high, and if it exceeds 10,000, there may be a problem in solubility.

[Toner particles]
The toner particles contained in the liquid developer according to the exemplary embodiment include a binder resin, and may include other components such as a colorant and a release agent as necessary.

(Binder resin)
The binder resin contains a polyester resin as a main component. The polyester resin is synthesized from an acid (polyhydric carboxylic acid) component and an alcohol (polyhydric alcohol) component. In the present embodiment, the “acid-derived constituent component” The component part which was an acid component is pointed out, and the "alcohol-derived component" refers to the component part which was an alcohol component before the synthesis of the polyester resin. The main component means 50 parts by mass or more with respect to 100 parts by mass of the binder resin in the toner particles.

[Acid-derived components]
The acid-derived component is not particularly limited, and aliphatic dicarboxylic acids and aromatic carboxylic acids are preferably used. Examples of the aliphatic dicarboxylic acid include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelic acid, sebacic acid, 1,9-nonanedicarboxylic acid, and 1,10-decanedicarboxylic acid. 1,11-undecanedicarboxylic acid, 1,12-dodecanedicarboxylic acid, 1,13-tridecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, 1,16-hexadecanedicarboxylic acid, 1,18-octadecanedicarboxylic acid, etc. Or lower alkyl esters and acid anhydrides thereof, but are not limited thereto. Examples of the aromatic carboxylic acid include lower alkyl esters and acid anhydrides of aromatic carboxylic acids such as terephthalic acid, isophthalic acid, phthalic anhydride, trimellitic anhydride, pyromellitic acid, and naphthalenedicarboxylic acid. Moreover, alicyclic carboxylic acids, such as cyclohexane dicarboxylic acid, etc. are mentioned. In order to secure better fixing properties, it is preferable to use a trivalent or higher carboxylic acid (trimellitic acid or acid anhydride thereof) together with a dicarboxylic acid in order to form a crosslinked structure or a branched structure. Specific examples of the alkenyl succinic acid include dodecenyl succinic acid, dodecyl succinic acid, stearyl succinic acid, octyl succinic acid, octenyl succinic acid and the like.

[Alcohol-derived components]
The alcohol-derived constituent component is not particularly limited, and examples of the aliphatic diol include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,18-octadecanediol, 1,20-eicosanediol and the like can be mentioned. In addition, diethylene glycol, triethylene glycol, neopentyl glycol, glycerin, alicyclic diols such as cyclohexanediol, cyclohexanedimethanol, hydrogenated bisphenol A, ethylene oxide adduct of bisphenol A, propylene oxide adduct of bisphenol A Aromatic diols such as are used. Further, in order to ensure good fixability, a trihydric or higher polyhydric alcohol (glycerin, trimethylolpropane, pentaerythritol) may be used in combination with the diol in order to take a crosslinked structure or a branched structure.

  The method for producing the polyester resin is not particularly limited, and may be produced by a general polyester polymerization method in which an acid component and an alcohol component are reacted. Examples thereof include direct polycondensation and transesterification. What is necessary is just to produce it properly according to a kind. The molar ratio (acid component / alcohol component) when the acid component reacts with the alcohol component varies depending on the reaction conditions and the like, and cannot be generally stated, but is usually about 1/1.

  The polyester resin may be produced, for example, at a polymerization temperature of 180 ° C. or higher and 230 ° C. or lower, and may be reacted while removing the water and alcohol generated during condensation by reducing the pressure in the reaction system as necessary. . When the monomer is not dissolved or compatible at the reaction temperature, the polymerization reaction may be partially accelerated or delayed, and many uncolored particles may be generated. It may be added and dissolved as a solubilizer. The polycondensation reaction may be carried out while distilling off the solubilizing solvent. If there is a monomer with poor compatibility in the copolymerization reaction, the monomer with poor compatibility is preliminarily condensed with the acid or alcohol to be polycondensed and then polymerized together with the main component. It may be condensed.

  Catalysts that may be used in the production of the polyester resin include alkali metal compounds such as sodium and lithium; alkaline earth metal compounds such as magnesium and calcium; metals such as zinc, manganese, antimony, titanium, tin, zirconium, and germanium Compound; Phosphorous acid compound, phosphoric acid compound, amine compound and the like. Among these, for example, it is preferable to use a tin-containing catalyst such as tin, tin formate, tin oxalate, tetraphenyltin, dibutyltin dichloride, dibutyltin oxide, and diphenyltin oxide.

  In the present embodiment, a compound having a hydrophilic polar group may be used as long as it is copolymerizable as a resin for an electrostatic charge image developing toner. Specific examples include dicarboxylic acid compounds in which an aromatic ring such as sulfonyl-terephthalic acid sodium salt or 3-sulfonylisophthalic acid sodium salt is directly substituted when the resin used is a polyester.

  The weight average molecular weight Mw of the polyester resin is preferably 5,000 or more, and more preferably 5,000 or more and 50,000 or less. When this polyester resin is included, it is excellent in rubbing property. When the weight average molecular weight Mw of the polyester resin is less than 5,000, it may be easily separated in some cases, and thus problems derived from the released resin (filming, increase in fine powder due to brittleness, deterioration in powder fluidity, etc.) May occur.

  The toner according to the exemplary embodiment may include a resin other than the polyester resin. Although it does not restrict | limit especially as resin other than a polyester resin, Specifically, Styrenes, such as styrene, parachlorostyrene, (alpha) -methylstyrene; Methyl acrylate, ethyl acrylate, acrylic acid n-propyl, butyl acrylate, Acrylic monomers such as lauryl acrylate and 2-ethylhexyl acrylate; methacrylic monomers such as methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate; and further acrylic Ethylenic unsaturated acid monomers such as acid, methacrylic acid and sodium styrenesulfonate; vinyl nitriles such as acrylonitrile and methacrylonitrile; vinyl ethers such as vinyl methyl ether and vinyl isobutyl ether; vinyl methyl ketone and vinyl Vinyl ketones such as ruethyl ketone and vinyl isopropenyl ketone; homopolymers of olefin monomers such as ethylene, propylene and butadiene, copolymers obtained by combining two or more of these monomers, or mixtures thereof; , Epoxy resin, polyester resin, polyurethane resin, polyamide resin, cellulose resin, polyether resin, etc., non-vinyl condensation resin, or a mixture of these with the vinyl resin, and vinyl monomers in the presence of these resins. Examples thereof include a graft polymer obtained by polymerization. These resins may be used alone or in combination of two or more.

  The content of the binder resin is, for example, in the range of 50% by mass to 99% by mass with respect to the entire toner particles.

  The toner particles according to the exemplary embodiment may contain other additives such as a colorant, a release agent, a charge control agent, silica powder, and a metal oxide as necessary. These additives may be added internally by, for example, kneading into a binder resin, or may be added externally by, for example, mixing the particles after obtaining toner particles.

  There is no restriction | limiting in particular as a coloring agent, A well-known pigment is used, A well-known dye may be included as needed. Specifically, the following pigments such as yellow, magenta, cyan, and black (black) are used.

  As yellow pigments, compounds represented by condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complex compounds, methine compounds, allylamide compounds and the like are used.

  As magenta pigments, condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinones, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, perylene compounds, and the like are used.

  Examples of cyan pigments include copper phthalocyanine compounds and derivatives thereof, anthraquinone compounds, basic dye lake compounds, and the like.

  As the black pigment, carbon black, aniline black, acetylene black, iron black and the like are used.

  The content of the colorant is, for example, in the range of 1% by mass to 50% by mass with respect to the entire toner particles.

  The release agent is not particularly limited, and examples thereof include plant waxes such as carnauba wax, wood wax and rice bran wax; animal waxes such as bees wax, insect wax, whale wax and wool wax; minerals such as montan wax and ozokerite. Synthetic waxes, synthetic fatty acid solid ester waxes such as Fischer-Tropsch wax (FT wax) having ester side chains, special fatty acid esters, polyhydric alcohol esters; paraffin wax, polyethylene wax, polypropylene wax, polytetrafluoroethylene wax, polyamide wax And synthetic waxes such as silicone compounds. Only one type of release agent may be used, or two or more types may be used.

  The content of the release agent is, for example, in the range of 1% by mass to 20% by mass with respect to the entire toner particles.

  There is no restriction | limiting in particular as a charge control agent, A conventionally well-known charge control agent is used. For example, positively chargeable charge control agents such as nigrosine dyes, fatty acid-modified nigrosine dyes, carboxyl group-containing fatty acid-modified nigrosine dyes, quaternary ammonium salts, amine compounds, amide compounds, imide compounds, organometallic compounds; oxycarboxylic acids And negatively chargeable charge control agents such as metal complexes of azo compounds, metal complex dyes and salicylic acid derivatives. Only one type of charge control agent may be used, or two or more types may be used.

  The metal oxide is not particularly limited, and examples thereof include titanium oxide, aluminum oxide, magnesium oxide, zinc oxide, strontium titanate, barium titanate, magnesium titanate, and calcium titanate. Only one type of metal oxide may be used, or two or more types may be used.

(Method for producing toner particles)
The method for producing the toner particles used in the present embodiment is not particularly limited, and is obtained by, for example, pulverizing toner produced by a production method such as pulverized toner, emulsion-dried toner in liquid, or polymerized toner in a carrier liquid. It is done.

  For example, binder resin, and if necessary, colorant, other additives, etc. are put into a mixing device such as a Henschel mixer and mixed, and this mixture is melted with a twin screw extruder, Banbury mixer, roll mill, kneader, etc. After kneading, cooling with a drum flaker, etc., coarsely pulverizing with a pulverizer such as a hammer mill, and further pulverizing with a pulverizer such as a jet mill, followed by classification using an air classifier, etc. can get.

  Also, the binder resin, if necessary, the colorant and other additives were dissolved in a solvent such as ethyl acetate, and emulsified and suspended in water to which a dispersion stabilizer such as calcium carbonate was added, and the solvent was removed. Thereafter, particles obtained by removing the dispersion stabilizer are filtered and dried to obtain an in-liquid emulsified dry toner.

  In addition, a polymerizable monomer, a colorant, and a polymerization initiator (for example, benzoyl peroxide, lauroyl peroxide, isopropyl peroxycarbonate, cumene hydroperoxide, 2,4-dichloroylbenzoyl peroxide) that form a binder resin , Methyl ethyl ketone peroxide, etc.) and other additives are added to the aqueous phase under stirring and granulated. After the polymerization reaction, the particles are filtered and dried to obtain a polymerized toner.

  The mixing ratio of each material (binder resin, colorant, other additives, etc.) for obtaining the toner may be set in consideration of required characteristics, low temperature fixability, color, and the like. The obtained toner is pulverized in carrier oil using a known pulverizer such as a ball mill, a bead mill, a high-pressure wet atomizer, etc., thereby obtaining toner particles for the liquid developer of this embodiment.

  In this embodiment, toner particles produced by the emulsion polymerization method in this embodiment have a narrow particle size distribution, and the process is produced by drying from an aqueous dispersion. The epoxy compound is subjected to a ring-opening addition reaction with an amino group. Since the amino-modified silicone / epoxy reactant has a structure having an alcoholic hydroxyl group (OH group) after the reaction, good dispersibility is imparted.

(Characteristics of toner particles)
The volume average particle diameter D50v of the toner particles is preferably 1.0 μm or more and 5.0 μm or less. By being in the said range, adhesive force is high and developability is improved. In addition, the resolution of the image can be improved. The volume average particle diameter D50v of the toner particles is more preferably in the range of 1.0 μm to 4.0 μm, and still more preferably in the range of 1.0 μm to 3.0 μm.

  When considering high image quality and safety, it is preferable that the particle diameter of the toner particles is small. In this case, the surface area of the toner particles increases, so the viscosity in the dispersion tends to increase. When the carrier liquid is silicone oil, it is difficult to improve dispersibility by adding a general surfactant, unlike particle dispersion in a general solvent system. In this embodiment, by using the amino-modified silicone / epoxy reactant as an additive in the silicone oil dispersion, the viscosity of the toner particles is reduced even when the toner particles have a small particle size, and a high-quality image is obtained. Although this mechanism is not clear, the structure of the amino-modified silicone / epoxy reaction product has an amino group and an alcoholic hydroxyl group (OH group) in the structure. It is considered that the dispersibility is improved due to the good correlation and the high adsorptivity to the toner particle surface.

For the volume average particle size D50v, number average particle size distribution index (GSDp), volume average particle size distribution index (GSDv), etc. of the toner particles, a laser diffraction / scattering type particle size distribution measuring device such as LA920 (manufactured by Horiba Ltd.) is used. Measured. Draw a cumulative distribution from the smaller diameter side for each particle size range (channel) divided based on the particle size distribution, and particles with a cumulative particle size of 16%, volume D16v, number D16p, and cumulative 50% The diameter is defined as volume D50v, number D50p, and the particle diameter at 84% cumulative is defined as volume D84v, number D84p. Using these, the volume average particle size distribution index (GSDv) is calculated as (D84v / D16v) ^1/2 and the number average particle size distribution index (GSDp) is calculated as (D84p / D16p) ^1/2 .

[Carrier liquid]
The carrier liquid is an insulating liquid for dispersing toner particles. Silicone oils (silicone solvents such as dimethyl silicone, diphenyl silicone, and hydrogen-modified silicone compounds having a degree of polymerization of greater than 20 and cyclic siloxane compounds) ). Of these, dimethyl silicone is preferable from the viewpoint of viscosity, dispersibility, and the like.

  The carrier liquid contained in the liquid developer according to the exemplary embodiment may be only one type or two or more types. In the case where the carrier liquid is used as a mixed system of two or more kinds, for example, a mixed system of a silicone solvent and vegetable oil can be used.

Examples of the volume resistivity of the carrier liquid include a range of 1.0 × 10 ¹⁰ Ω · cm to 1.0 × 10 ¹⁴ Ω · cm, and 1.0 × 10 ¹⁰ Ω · cm to 1.0 × It may be in a range of 10 ¹³ Ω · cm or less.

  The carrier liquid is made of various auxiliary materials such as dispersants, emulsifiers, surfactants, stabilizers, wetting agents, thickeners, foaming agents, antifoaming agents, coagulants, gelling agents, anti-settling agents, charging agents. It may contain a control agent, an antistatic agent, an anti-aging agent, a softening agent, a plasticizer, a filler, a flavoring agent, an anti-tacking agent, a release agent and the like.

[Method for producing liquid developer]
In the liquid developer according to the exemplary embodiment, the toner particles and the carrier liquid are mixed and pulverized using a dispersing machine such as a ball mill, a sand mill, an attritor, or a bead mill, and the toner particles are mixed in the carrier liquid. Obtained by dispersing. The dispersion of the toner particles in the carrier liquid is not limited to a disperser, and may be dispersed by rotating a special stirring blade at a high speed like a mixer, or by the shearing force of a rotor / stator known as a homogenizer. Alternatively, it may be dispersed by ultrasonic waves.

  The concentration of the toner particles in the carrier liquid should be in the range of 0.5% by mass or more and 40% by mass or less from the viewpoint of controlling the viscosity of the developer appropriately and facilitating the circulation of the developer in the developing machine. Is preferable, and the range of 1% by mass to 30% by mass is more preferable.

  Thereafter, the obtained dispersion liquid may be filtered using, for example, a filter such as a membrane filter having a pore diameter of about 100 μm to remove dust, coarse particles, and the like.

<Developer cartridge, process cartridge, image forming apparatus>
The image forming apparatus according to the present embodiment includes, for example, an image carrier (hereinafter sometimes referred to as “photosensitive member”), a charging unit that charges the surface of the image carrier, and a latent image ( The latent image forming means for forming the electrostatic latent image) and the latent image formed on the surface of the image holding member are developed with the liquid developer according to the embodiment held on the surface of the developer holding member. Developing means for forming a toner image, transfer means for transferring the toner image formed on the surface of the image carrier onto the recording medium, and fixing the toner image transferred to the recording medium onto the recording medium Fixing means to be formed.

  In the image forming apparatus, for example, the part including the developing unit may have a cartridge structure (process cartridge) that is detachable from the main body of the image forming apparatus. The process cartridge is not particularly limited as long as it contains the liquid developer according to the present embodiment. The process cartridge includes, for example, a developing unit that stores the liquid developer according to the present embodiment and develops a latent image formed on the image carrier with the liquid developer to form a toner image. It is to be attached to and detached from.

  The developer cartridge according to the present embodiment is not particularly limited as long as it contains the liquid developer according to the present embodiment. The developer cartridge contains, for example, the liquid developer according to the present embodiment, and includes an image forming apparatus including a developing unit that forms a toner image by developing the latent image formed on the image holding member with the liquid developer. It is to be attached to and detached from.

  Hereinafter, an image forming apparatus using a liquid developer in the present embodiment will be described with reference to the drawings.

  FIG. 1 is a schematic configuration diagram illustrating an example of an image forming apparatus according to the present embodiment. The image forming apparatus 100 includes a photosensitive member (image holding member) 10, a charging device (charging unit) 20, an exposure device (latent image forming unit) 12, a developing device (developing unit) 14, and an intermediate transfer member (transfer). Means) 16, a cleaner (cleaning means) 18, and a transfer fixing roller (transfer means, fixing means) 28. The photosensitive member 10 has a cylindrical shape, and a charging device 20, an exposure device 12, a developing device 14, an intermediate transfer member 16, and a cleaner 18 are sequentially provided on the outer periphery of the photosensitive member 10.

  Hereinafter, the operation of the image forming apparatus 100 will be described.

  The charging device 20 charges the surface of the photoconductor 10 to a predetermined potential (charging process), and based on the image signal, the exposure device 12 exposes the charged surface with, for example, a laser beam to form a latent image (static image). Electrostatic latent image) is formed (latent image forming step).

  The developing device 14 includes a developing roller 14a and a developer storage container 14b. The developing roller 14a is provided such that a part thereof is immersed in the liquid developer 24 stored in the developer storage container 14b. The liquid developer 24 includes an insulating carrier liquid, toner particles containing a binder resin, and the charge control agent.

  In the liquid developer 24, the toner particles are dispersed. For example, the liquid developer 24 is further stirred by a stirring member provided in the developer container 14b. Variation in the position of the concentration of is reduced. Thus, the liquid developer 24 with reduced toner particle density variation is supplied to the developing roller 14a rotating in the direction of arrow A in the figure.

  The liquid developer 24 supplied to the developing roller 14a is conveyed to the photoconductor 10 in a state where the liquid supply 24 is limited to a constant supply amount by the regulating member, and at a position where the developing roller 14a and the photoconductor 10 are close (or in contact). It is supplied to the electrostatic latent image. As a result, the electrostatic latent image is visualized to become a toner image 26 (development process).

  The developed toner image 26 is conveyed to the photosensitive member 10 that rotates in the direction of arrow B in the figure, and is transferred to a paper (recording medium) 30. In this embodiment, the photosensitive member 26 is transferred before being transferred to the paper 30. The toner image is temporarily transferred to the intermediate transfer body 16 in order to improve the transfer efficiency to the recording medium including the separation efficiency of the toner image from the toner 10, and to perform fixing simultaneously with the transfer to the recording medium (intermediate transfer step). . At this time, a peripheral speed difference may be provided between the photosensitive member 10 and the intermediate transfer member 16.

  Next, the toner image conveyed in the direction of arrow C by the intermediate transfer body 16 is transferred to the paper 30 and fixed at the position of contact with the transfer and fixing roller 28 (transfer process, fixing process). The transfer fixing roller 28 sandwiches the paper 30 together with the intermediate transfer body 16, and causes the toner image on the intermediate transfer body 16 to adhere to the paper 30. As a result, the toner image is transferred to the paper 30, and the toner image is fixed on the paper to form a fixed image 29. The fixing of the toner image is preferably performed by applying a heating element to the transfer fixing roller 28 and applying pressure and heating. The fixing temperature is usually in the range of 120 ° C. or higher and 200 ° C. or lower.

  If the intermediate transfer member 16 has a roller shape as shown in FIG. 1, it forms a roller pair with the transfer fixing roller 28. Therefore, the intermediate transfer member 16 and the transfer fixing roller 28 conform to the fixing roller and the pressing roller in the fixing device, respectively. It shows a fixing function. That is, when the sheet 30 passes through the nip formed between the intermediate transfer body 16 and the transfer fixing roller 28, the toner image is transferred and heated and pressed against the intermediate transfer body 16 by the transfer fixing roller 28. The As a result, the binder resin in the toner particles constituting the toner image is softened, and the toner image is infiltrated into the fibers of the paper 30 to form a fixed image 29 on the paper 30.

  In this embodiment, fixing is performed simultaneously with the transfer to the paper 30. However, the transfer process and the fixing process may be performed separately, and the fixing may be performed after the transfer. In this case, the transfer roller for transferring the toner image from the photoconductor 10 has a function according to the intermediate transfer body 16.

  On the other hand, in the photoreceptor 10 that has transferred the toner image 26 to the intermediate transfer member 16, the toner particles remaining without being transferred are conveyed to a contact position with the cleaner 18 and collected by the cleaner 18. If the transfer efficiency is close to 100% and residual toner is not a problem, the cleaner 18 may not be provided.

  The image forming apparatus 100 may further include a neutralization device (not shown) that neutralizes the surface of the photoconductor 10 after the transfer and before the next charging.

  For example, the charging device 20, the exposure device 12, the developing device 14, the intermediate transfer member 16, the transfer fixing roller 28, and the cleaner 18 that are provided in the image forming apparatus 100 are all synchronized with the rotational speed of the photosensitive member 10. May be operated.

  Hereinafter, although an example and a comparative example are given and the present invention is explained more concretely in detail, the present invention is not limited to the following examples.

[Example 1]
(Preparation of amino-modified silicone / epoxy reactant 1)
Amino-modified silicone oil KF-869 (manufactured by Shin-Etsu Silicone, in the above formula (1), X is a methyl group, Y is a methyl group, Z is R ² NHR ³ NH ₂ , m is 40, and n is 1. R ² is propylene, R ³ is ethylene, weight average molecular weight: 3800) 100 parts by mass of toluene 50 parts by mass, monoepoxy compound (in the above formula (2), R ⁴ is a hydroxyethyl group) 63 parts by mass was charged into a reactor and stirred at 80 ° C. for 5 hours to carry out the reaction. Under reduced pressure of 10 mmHg, the low fraction was removed at 80 ° C., and amino-modified silicone / epoxy reactant 1 (weight average molecular weight: 4000 ) Was prepared.

(Preparation of liquid developer)
40 parts by mass of a cyan pigment (CI Pigment Blue 15: 3, manufactured by Clariant) was added to 60 parts by mass of a polyester resin (manufactured by Kao Corporation, FS-1 (product number), weight average molecular weight: 14000). And kneading with a pressure kneader. The kneaded product was coarsely pulverized to prepare a cyan pigment master batch.

Next, a mixture having the following composition was dissolved and dispersed in a ball mill for 24 hours.
Polyester resin (manufactured by Kao Corporation, FS-1 (product number), weight average molecular weight: 14000): 70 parts by mass The above-mentioned cyan pigment master batch: 25 parts by mass Ethyl acetate: 100 parts by mass

On the other hand, 20 parts by mass of calcium carbonate (manufactured by Maruo Calcium Co., Ltd., Luminous) as an aqueous dispersion prepared by dissolving 60 parts by mass of sodium chloride (manufactured by Wako Pure Chemical Industries, Ltd.) in 240 parts by mass of ion-exchanged water. And dispersed with a ball mill for 24 hours to obtain a dispersion medium. 100 parts by mass of the mixture is added to 170 parts by mass of this dispersion medium, and the mixture is emulsified for 1 minute at 8,000 rpm to 24,000 rpm using an emulsifier (IKA, Ultratax T-25). Got. The suspension was put into a separable flask equipped with a stirrer, thermometer, cooling and a nitrogen introduction tube, and stirred for 3 hours at 60 ° C. while flowing nitrogen through the nitrogen introduction tube to distill off ethyl acetate. .
After standing to cool, 10% hydrochloric acid aqueous solution was added to the mixture to decompose calcium carbonate, solids were separated by a centrifuge, washed with 1 L of ion-exchanged water three times, and a volume average particle size of 3.0 μm. A slurry of toner particles was obtained. The slurry was subjected to suction filtration and repeatedly washed with water, and then the obtained cake was freeze-dried at 20 ° C. for 24 hours to recover 57 parts by mass of dry cyan toner particles.

  30 parts by mass of the cyan toner particles obtained above were mixed with 70 parts by mass of silicone oil (KF-96-20cs; manufactured by Shin-Etsu Chemical Co., Ltd.) and 0.1 parts by mass of amino-modified silicone / epoxy reactant 1 as a dispersant. Were mixed with a part and dispersed with a homogenizer to obtain a liquid developer having a solid content concentration of 30% by mass.

<Evaluation>
[Viscosity evaluation]
Solid content concentration when the shear rate was changed from 0.01 s ^-1 to 1,000 s ^{-1 in} the viscosity measurement mode using a visco-viscoelasticity measuring machine (made by MARS HAAKE) with a 35 mm diameter cone plate. The shear rate dependency of the viscosity of a 30% by mass liquid developer was confirmed. Viscosity at a shear rate of 1 s ⁻¹ : The value of η was evaluated according to the following criteria. The results are shown in Table 1.
A: η ≦ 2000 mPas
○: 2000 mPas <η ≦ 4000 mPas
Δ: 4000 mPas <η ≦ 7000 mPas
×: 7000 mPas> η

[Dispersibility evaluation]
The liquid developer was centrifuged for 3 minutes at a rotational speed of 3,000 rpm using a centrifuge (MT-300, manufactured by Tommy). The sample was directly set on a shaker and stirred for 10 minutes. The developer was taken out and redispersibility was confirmed. Dispersibility was evaluated according to the following criteria. The results are shown in Table 1.
◎: Dispersed before setting on a shaker ○: Separated by centrifugation but redispersed within 2 minutes with a shaker △: Separated by centrifugation but redispersed within 2 to 10 minutes with a shaker ×: Separation by centrifugation, but the shaker remains separated even over 10 minutes

[Operability evaluation]
The fluidity of the pipe when it was circulated through the silicone tube (inner diameter 6.35 mm, length 9.53 mm) using a pump (manufactured by EYELA, RP-1000) was evaluated. The operability was evaluated according to the following criteria. The results are shown in Table 1.
◎: Developer is constantly circulating without clogging the tube ○: Developer is circulating without clogging the tube △: Initially flows through the tube, but sometimes Unstable ×: The tube is clogged and cannot be circulated

[Image evaluation]
The liquid developer was put into a disposable cell (made of polystyrene), and two transparent electrodes facing each other with a gap of 1 mm were immersed therein, and a voltage of 300 V was applied for 30 seconds. The operation of changing the polarity of the electrode and applying a voltage of 300 V again for 30 seconds was repeated five times. Then, the electrode was pulled up, and the toner deposited on the electrode was transferred to J-coated paper manufactured by Fuji Xerox. The transferred image was fixed using an external fixing device at a fixing speed of 500 mm / sec under a nip of 6 mm and a fixing temperature of 140 ° C. The state of the liquid developer after image formation was visually confirmed, and the obtained image was evaluated according to the following criteria.
A: The dispersion of the developer in the disposable was uniform, and an image density of 1.5 or more was obtained. O: The developer in the disposable was partially thickened, but the image density was 1. An image of 0.0 or more was obtained. Δ: The developer in the disposable was partially agglomerated, and the density of the obtained image was 1.0 or less. ×: The developer in the disposable was separated. I couldn't get any images

[Example 2]
As a dispersant, KF-877 (manufactured by Shin-Etsu Silicone Co., Ltd., in the above formula (1), X is a methyl group, Y is a methyl group, Z is R ² NHR ³ NH ₂ , m is 55, n is 1, 0.1 parts by mass of a reaction product (weight average molecular weight: 5000) of an amino-modified silicone oil in which ² is propylene and R ³ is ethylene and a monoepoxy compound in which R ⁴ is hydrogen in the above formula (2) A liquid developer was produced in the same manner as in Example 1 except that. Hereinafter, evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.

[Example 3]
A liquid developer was prepared in the same manner as in Example 1 except that 1.0 part by mass of the amino-modified silicone / epoxy reactant 1 was added. Hereinafter, evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.

[Example 4]
A liquid developer was prepared in the same manner as in Example 1 except that 0.001 part by mass of the amino-modified silicone / epoxy reactant 1 was added. Hereinafter, evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.

[Example 5]
A liquid developer was prepared in the same manner as in Example 1 except that 1.5 parts by mass of the amino-modified silicone / epoxy reactant 1 was added. Hereinafter, evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.

[Example 6]
A liquid developer was prepared in the same manner as in Example 1 except that 0.0001 part by mass of the amino-modified silicone / epoxy reactant 1 was added. Hereinafter, evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.

[Example 7]
As a dispersant, amino-modified silicone oil KF-861 (manufactured by Shin-Etsu Silicone, in the above formula (1), X is methyl, Y is methyl, Z is R ² NHR ³ NH ₂ , m is 20, and n is 1. R ² is propylene, R ³ is an amino-modified silicone oil in which ethylene is ethylene), and R ² is a butyl-based monoepoxy compound in the above formula (2), and a reaction product 2 (weight average molecular weight: 2100) is 0.1 A liquid developer was prepared in the same manner as in Example 1 except for adding part by mass. Hereinafter, evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.

[Example 8]
As a dispersant, KF-864 (manufactured by Shin-Etsu Silicone, in the above formula (1), X is a methyl group, Y is methyl, Z is —R ¹ NH ₂ , m is 60, n is 1, and R ¹ is propylene. Amino-modified silicone oil) and R ⁴ is hydroxyethyl in the above formula (2), except that 0.1 part by mass of a reaction product 3 (weight average molecular weight: 5000) was added. In the same manner as in Example 1, a liquid developer was prepared. Hereinafter, evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.

[Comparative Example 1]
A liquid developer was prepared in the same manner as in Example 1 except that the dispersant was not added. Hereinafter, evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.

[Comparative Example 2]
A liquid developer was prepared in the same manner as in Example 1 except that 0.1 part by mass of KF-861 (manufactured by Shin-Etsu Silicone) was used as a dispersant without reacting with the epoxy compound. Hereinafter, evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.

  As described above, in the example using the liquid developer containing the carrier liquid containing the silicone oil, the toner particles containing the polyester resin, and the reaction product of the amino-modified silicone oil and the epoxy compound, compared with the comparative example. The viscosity was low. Moreover, in the Example, it was excellent in the dispersibility and piping fluidity | liquidity compared with the comparative example.

  The liquid developers of Examples 1 and 2 had low viscosity, good dispersibility, almost never clogged the tube, and good operability. The liquid developer of Comparative Example 1 seemed to be dispersed, but when confirmed by dilution, the dispersibility was poor and the viscosity was high. Since the additive of Comparative Example 2 in which clogging occurred in the tube did not react amino-modified silicone with an epoxy compound, the dispersibility was slightly improved compared to Comparative Example 1, but neither the viscosity nor the operability was improved.

  DESCRIPTION OF SYMBOLS 10 Photosensitive body (image holding body), 12 Exposure apparatus (latent image forming means), 14 Developing apparatus (developing means), 14a Developing roller (developer holding body), 14b Developer accommodating container, 16 Intermediate transfer body (transfer means) ), 18 cleaner (cleaning means), 20 charging device (charging means), 24 liquid developer, 26 toner image, 28 transfer fixing roller (transfer means, fixing means), 29 fixed image, 30 paper (recording medium), 100 Image forming apparatus.

Claims (6)

A carrier liquid containing silicone oil;
Toner particles containing polyester resin;
A reaction product of an amino-modified silicone oil and an epoxy compound;
A liquid developer comprising: The silicone oil is dimethyl silicone;
2. The liquid development according to claim 1, wherein the amino-modified silicone oil is a compound represented by the following general formula (1), and the epoxy compound is a compound represented by the following general formula (2). Agent.

(1)
(In the formula (1), X, Y and Z each independently represent a methyl group, —R ¹ NH ₂ or R ² NHR ³ NH ₂ , and at least one of X, Y and Z is — R ¹ NH ₂ or R ² NHR ³ NH _{2 When} either or both of X and Y are —R ¹ NH ₂ or R ² NHR ³ NH ₂ , m represents an integer of 1 or more and 100 or less. , N represents an integer of 0 to 100, and when X and Y are not —R ¹ NH ₂ or R ² NHR ³ NH ₂ , m represents an integer of 0 to 100, and n is And represents an integer of 1 to 100. R ¹ , R ² and R ³ each independently represents a divalent alkyl group having 1 to 8 carbon atoms.

(2)
(In formula (2), R ⁴ represents a hydrogen atom, an alkyl group or an alkyl alcohol group.)   A developer cartridge containing the liquid developer according to claim 1.   A process cartridge in which the liquid developer according to claim 1 is contained. An image carrier,
Latent image forming means for forming a latent image on the surface of the image carrier;
A developing unit that forms the toner image by developing the latent image formed on the surface of the image carrier with the liquid developer according to claim 1 held on the surface of the developer carrier;
Transfer means for transferring the toner image formed on the surface of the image carrier onto a recording medium;
Fixing means for fixing the toner image transferred to the recording medium to the recording medium to form a fixed image;
An image forming apparatus comprising: A latent image forming step of forming a latent image on the surface of the image carrier;
A developing step of developing the latent image formed on the surface of the image carrier with the liquid developer according to claim 1 held on the surface of the developer carrier to form a toner image;
A transfer step of transferring the toner image formed on the surface of the image carrier onto a recording medium;
A fixing step of fixing the toner image transferred to the recording medium to the recording medium to form a fixed image;
An image forming method comprising:

Images