JP2015184474A - Toner for electrostatic charge image development, electrostatic charge image developer, toner cartridge, process cartridge, image forming apparatus, and image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a toner for electrostatic charge image development that suppresses the occurrence of unevenness in image density.SOLUTION: There is provided a toner for electrostatic charge image development that includes toner particles containing a binder resin and having at least one compound selected from alkylated polyalkylene biguanide, alkylated polyalkylene guanidine, and alkylated polyalkylene imine, on the surface thereof.

Description

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

  Various toners used for electrophotographic image formation and various ink compositions and liquid compositions used for inkjet image formation are known. For example, Patent Document 1 discloses a black toner obtained by surface-modifying toner base particles containing carbon black and a binder resin with polyalkyleneimine. Patent Document 2 discloses an ink containing a dye having an anionic group and a liquid composition containing a guanidine derivative which is attached to a recording medium prior to the ink.

Japanese Patent No. 5115379 JP 2003-237218 A

  An object of the present invention is to provide a toner for developing an electrostatic image that suppresses occurrence of unevenness in image density.

The above problem is solved by the following means. That is,
The invention according to claim 1
Toner particles containing a binder resin and having at least one compound selected from alkylated polyalkylene biguanides, alkylated polyalkylene guanidines, and alkylated polyalkylene imines on the surface;
A toner for developing an electrostatic charge image.

The invention according to claim 2
The electrostatic charge image developing toner according to claim 1, wherein the compound has a remaining ratio of imino groups in the molecule of 20% or more and 50% or less.

The invention according to claim 3
3. The electrostatic image developing toner according to claim 1, wherein the toner particles have the compound in a range of 0.0001 g or more and 0.0010 g or less per 1 g of toner particles on the surface thereof.

The invention according to claim 4
4. The electrostatic image developing toner according to claim 1, wherein the toner particles have at least an alkylated polyhexamethylene biguanide on the surface as the compound. 5.

The invention according to claim 5
4. The electrostatic image developing toner according to claim 1, wherein the toner particles have at least alkylated polyhexamethylene guanidine on the surface as the compound. 5.

The invention according to claim 6
4. The electrostatic image developing toner according to claim 1, wherein the toner particles have at least an alkylated polyethyleneimine on the surface as the compound. 5.

The invention according to claim 7 provides:
An electrostatic charge image developer comprising the electrostatic charge image developing toner according to claim 1.

The invention according to claim 8 provides:
Containing the toner for developing an electrostatic charge image according to any one of claims 1 to 6,
A toner cartridge to be attached to and detached from the image forming apparatus.

The invention according to claim 9 is:
A developing means for containing the electrostatic charge image developer according to claim 7 and developing the electrostatic charge image formed on the surface of the image carrier as a toner image by the electrostatic charge image developer,
A process cartridge attached to and detached from the image forming apparatus.

The invention according to claim 10 is:
An image carrier,
Charging means for charging the surface of the image carrier;
An electrostatic charge image forming means for forming an electrostatic charge image on the surface of the charged image carrier;
Development means for containing the electrostatic image developer according to claim 7 and developing the electrostatic image formed on the surface of the image carrier as a toner image by the electrostatic image developer;
Transfer means for transferring a toner image formed on the surface of the image carrier to the surface of a recording medium;
Fixing means for fixing the toner image transferred to the surface of the recording medium;
An image forming apparatus comprising:

The invention according to claim 11 is:
A charging step for charging the surface of the image carrier;
An electrostatic charge image forming step of forming an electrostatic charge image on the surface of the charged image carrier;
A developing step of developing an electrostatic charge image formed on the surface of the image carrier as a toner image with the electrostatic charge image developer according to claim 7;
A transfer step of transferring a toner image formed on the surface of the image carrier to the surface of a recording medium;
A fixing step of fixing the toner image transferred to the surface of the recording medium;
An image forming method comprising:

According to the first aspect of the present invention, there is provided a toner for developing an electrostatic charge image that suppresses the occurrence of uneven image density as compared with the case where the compound is not alkylated.
According to the second aspect of the present invention, there is provided an electrostatic charge image developing toner that further suppresses the occurrence of unevenness in image density as compared with the case where the residual ratio of the imino group in the molecule of the compound is outside the range. Is done.
According to the third aspect of the present invention, there is provided an electrostatic image developing toner that further suppresses occurrence of unevenness in image density as compared with the case where the amount of the compound is out of the range.

According to the fourth aspect of the present invention, there is provided an electrostatic image developing toner that suppresses the occurrence of uneven image density as compared with the case where the alkylated polyhexamethylene biguanide is not alkylated.
According to the fifth aspect of the present invention, there is provided an electrostatic image developing toner that suppresses the occurrence of uneven image density as compared with the case where the alkylated polyhexamethylene guanidine is not alkylated.
According to the sixth aspect of the present invention, there is provided an electrostatic image developing toner that suppresses the occurrence of unevenness in image density as compared with the case where the alkylated polyethyleneimine is not alkylated.

According to the seventh aspect of the present invention, there is provided an electrostatic charge image developer that suppresses the occurrence of uneven image density as compared with the case where the compound in the toner is not alkylated.
According to the eighth aspect of the present invention, there is provided a toner cartridge that suppresses the occurrence of uneven image density as compared with the case where the compound in the toner is not alkylated.
According to the ninth aspect of the present invention, there is provided a process cartridge that suppresses the occurrence of uneven image density as compared with a case where the compound in the toner in the developer is not alkylated.
According to the tenth aspect of the present invention, there is provided an image forming apparatus that suppresses occurrence of unevenness in image density as compared with a case where the compound in the toner in the developer is not alkylated.
According to the eleventh aspect of the present invention, there is provided an image forming method that suppresses occurrence of unevenness in image density as compared with a case where the compound in the toner in the developer is not alkylated.

1 is a schematic configuration diagram illustrating an example of an image forming apparatus according to an exemplary embodiment. It is a schematic block diagram which shows an example of the process cartridge which concerns on this embodiment.

  Embodiments of the present invention will be described below. These descriptions and examples are illustrative of the invention and are not intended to limit the scope of the invention.

  In the present specification, (meth) acryl means acrylic or methacrylic, (meth) acrylic acid means acrylic acid or methacrylic acid, and (meth) acrylo means acrylo or methacrylo.

<Toner for electrostatic image development>
The electrostatic image developing toner (also referred to as “toner”) according to this embodiment has at least one compound selected from alkylated polyalkylene biguanides, alkylated polyalkylene guanidines, and alkylated polyalkyleneimines on the surface. Having toner particles.

In the present embodiment, the alkylated polyalkylene biguanide means that at least a part of imino groups (—NH—, ═NH) present in the polyalkylene biguanide molecule is alkylated (that is, bonded to a nitrogen atom). In which a hydrogen atom is substituted with an alkyl group).
In the present embodiment, the alkylated polyalkyleneguanidine means that at least part of imino groups (—NH—, ═NH) present in the polyalkyleneguanidine molecule is alkylated (that is, bonded to a nitrogen atom). In which a hydrogen atom is substituted with an alkyl group).
In this embodiment, the alkylated polyalkyleneimine is a hydrogen atom in which at least a part of a plurality of imino groups (—NH—) present in the polyalkyleneimine molecule is alkylated (that is, bonded to a nitrogen atom). Are substituted with an alkyl group).
Hereinafter, alkylated polyalkylene biguanides, alkylated polyalkylene guanidines, and alkylated polyalkyleneimines are collectively referred to as “specific compounds”.

  The toner according to the present embodiment hardly causes unevenness in image density when an image is formed. The presumed mechanism is explained below.

Conventionally, as a means for imparting positive charge to a toner, it is known that the surface of the toner particle is modified with a polyalkyleneimine or a guanidine derivative. However, when an image is formed with a toner whose surface is modified with polyalkyleneimine or the like, unevenness in image density may occur, particularly in a high temperature and high humidity environment (for example, 28 ° C. or higher and 80% RH or higher). Cheap. This unevenness in image density is presumed to be caused by the following phenomenon. In other words, ozone generated by the discharge of the charging device oxidizes imino groups present in molecules such as polyalkyleneimine to produce nitrogen oxides, which adhere to the photoreceptor and absorb moisture. As a result, the surface potential of the photoconductor is decreased by discharging, and as a result, the amount of toner adhering to the image portion where the toner originally adheres to a part of the photoconductor is reduced, and unevenness of the image density is generated. It has been.
If the phenomenon of discharging the surface potential of the photoconductor further proceeds to the entire photoconductor, the image density decreases, and if it proceeds to a part of the photoconductor, problems such as missing images or white spots may occur. End up.

  In contrast, in the present invention, the compound present on the toner particle surface is the specific compound. Since the specific compound is a compound in which at least a part of the imino group present in the molecule is alkylated, the generation of nitrogen oxides on the toner particle surface is suppressed, and the occurrence of uneven image density is suppressed. It is thought that.

  Hereinafter, the configuration of the toner according to the exemplary embodiment will be described in detail.

[Toner particles]
The toner particles include a binder resin, and may further include a colorant, a release agent, and other internal additives. The toner particles have at least one compound selected from alkylated polyalkylene biguanides, alkylated polyalkylene guanidines, and alkylated polyalkyleneimines (collectively “specific compounds”) on the surface thereof. The specific compound is obtained by, for example, a chemical bond (covalent bond, ionic bond) between an acidic group of a binder resin and a basic group of the specific compound; a bond by intermolecular force between a molecule on the toner particle surface and the specific compound; It adheres to the surface of the particles.

  Since the specific compound is a positively charged compound, the toner according to the present exemplary embodiment is a positively charged toner because the toner particles have the specific compound on the surface.

-Alkylated polyalkylene biguanide-
In this embodiment, the alkylated polyalkylene biguanide is a polyalkylene biguanide in which at least a part of the imino group is alkylated. Of the imino groups (—NH—, ═NH), the alkylation of ═NH may be mono- or di-substituted, and is preferably di-substituted from the viewpoint of further suppressing the occurrence of uneven image density. The primary amino group (—NH ₂ ) in the molecule is preferably partially or entirely alkylated from the viewpoint of further suppressing the occurrence of image density unevenness.

  In this embodiment, the alkylated polyalkylene biguanide includes its acid addition salt. Acid addition salts of alkylated polyalkylene biguanides include phosphate, hydrochloride, nitrate, sulfate, carbonate, lactate, formate, acetate, benzoate, dehydroacetate, propionate, gluconic acid Salt, sorbate, fumarate, maleate, paratoluenesulfonate, etc. are mentioned.

  The alkylated polyalkylene biguanide preferably has a residual ratio of imino groups in the molecule (number of imino groups ÷ total number of nitrogen atoms) of 20% or more and 50% or less. When the residual ratio is 50% or less, the generation of nitrogen oxides in the image forming apparatus is further suppressed, and the occurrence of uneven image density is further suppressed. When the residual ratio is 20% or more, the alkylated polyalkylene biguanide easily adheres to the surface of the toner particles, the positive charge amount of the toner is in a favorable range, and the occurrence of uneven image density is further suppressed. In view of the above, the remaining rate is more preferably 25% or more and 45% or less, and further preferably 30% or more and 40% or less.

  The alkyl group for alkylating the imino group is preferably an alkyl group having 1 to 12 carbon atoms, and more preferably an alkyl group having 1 to 6 carbon atoms. The alkyl group may be linear, branched, cyclic, or a combination of two or more selected from these. Specifically, for example, a linear alkyl group such as methyl group, ethyl group, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group, n-decyl, n-dodecyl; -Propyl group, iso-butyl group, sec-butyl group, tert-butyl group, iso-pentyl group, neopentyl group, tert-pentyl group, iso-hexyl group, sec-hexyl group, tert-hexyl group, etc. A cyclic alkyl group such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, and a cyclohexyl group.

  The alkylene group in the alkylated polyalkylene biguanide molecule is preferably an alkylene group having 1 to 12 carbon atoms, and more preferably an alkylene group having 1 to 6 carbon atoms. The alkylene group may be any of linear, branched, cyclic, and combinations of two or more selected from these. Specifically, for example, methylene group, ethylene group, n-propylene group, n-butylene group, n-pentylene group, n-hexylene group (hexamethylene group), n-octalene group (octamethylene group), etc. Chain-like alkylene group: iso-propylene group, iso-butylene group, sec-butylene group, tert-butylene group, iso-pentylene group, neopentylene group, tert-pentylene group, iso-hexylene group, sec-hexylene group, tert A branched alkylene group such as a hexylene group; a cyclic alkylene group such as a cyclopropylene group, a cyclobutylene group, a cyclopentylene group, or a cyclohexylene group;

  Specific examples of the alkylated polyalkylene biguanide include polymethylene biguanide, polyethylene biguanide, polytetramethylene biguanide, polyhexamethylene biguanide, and acid addition salts thereof in which at least a part of the imino group is alkylated. It is done. The residual ratio of imino groups in these molecules is preferably 20% or more and 50% or less, more preferably 25% or more and 45% or less, and further preferably 30% or more and 40% or less.

  As the alkylated polyalkylene biguanide, polyhexamethylene biguanide (“alkyl”) in which at least a part of the imino group is alkylated in view of the reactivity with the binder resin and the amount of positive charge per unit mass. Polyhexamethylene biguanide), and acid addition salts thereof. As the acid addition salt, phosphate or hydrochloride is desirable.

-Alkylated polyalkyleneguanidine-
In this embodiment, the alkylated polyalkylene guanidine is a polyalkylene guanidine in which at least a part of the imino group is alkylated. Of the imino groups (—NH—, ═NH), the alkylation of ═NH may be mono- or di-substituted, and is preferably di-substituted from the viewpoint of further suppressing the occurrence of uneven image density. The primary amino group (—NH ₂ ) in the molecule is preferably partially or entirely alkylated from the viewpoint of further suppressing the occurrence of image density unevenness.

  In this embodiment, the alkylated polyalkyleneguanidine includes its acid addition salt. Acid addition salts of alkylated polyalkyleneguanidines include phosphate, hydrochloride, nitrate, sulfate, carbonate, lactate, formate, acetate, benzoate, dehydroacetate, propionate, gluconic acid Salt, sorbate, fumarate, maleate, paratoluenesulfonate, etc. are mentioned.

  The alkylated polyalkyleneguanidine desirably has a residual ratio of imino groups in the molecule (number of imino groups ÷ total number of nitrogen atoms) of 20% or more and 50% or less. When the residual ratio is 50% or less, the generation of nitrogen oxides in the image forming apparatus is further suppressed, and the occurrence of uneven image density is further suppressed. When the residual ratio is 20% or more, the alkylated polyalkyleneguanidine easily adheres to the surface of the toner particles, the positive charge amount of the toner is in a favorable range, and the occurrence of uneven image density is further suppressed. In view of the above, the remaining rate is more preferably 25% or more and 45% or less, and further preferably 30% or more and 40% or less.

  The alkyl group for alkylating the imino group is preferably an alkyl group having 1 to 12 carbon atoms, and more preferably an alkyl group having 1 to 6 carbon atoms. The alkyl group may be linear, branched, cyclic, or a combination of two or more selected from these. Specifically, for example, a linear alkyl group such as methyl group, ethyl group, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group, n-decyl, n-dodecyl; -Propyl group, iso-butyl group, sec-butyl group, tert-butyl group, iso-pentyl group, neopentyl group, tert-pentyl group, iso-hexyl group, sec-hexyl group, tert-hexyl group, etc. A cyclic alkyl group such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, and a cyclohexyl group.

  The alkylene group in the alkylated polyalkyleneguanidine molecule is preferably an alkylene group having 1 to 12 carbon atoms, and more preferably an alkylene group having 1 to 6 carbon atoms. The alkylene group may be any of linear, branched, cyclic, and combinations of two or more selected from these. Specifically, for example, methylene group, ethylene group, n-propylene group, n-butylene group, n-pentylene group, n-hexylene group (hexamethylene group), n-octalene group (octamethylene group), etc. Chain-like alkylene group: iso-propylene group, iso-butylene group, sec-butylene group, tert-butylene group, iso-pentylene group, neopentylene group, tert-pentylene group, iso-hexylene group, sec-hexylene group, tert A branched alkylene group such as a hexylene group; a cyclic alkylene group such as a cyclopropylene group, a cyclobutylene group, a cyclopentylene group, or a cyclohexylene group;

  Specific examples of the alkylated polyalkylene guanidine include polymethylene guanidine, polyethylene guanidine, polytetramethylene guanidine, polyhexamethylene guanidine, and acid addition salts thereof in which at least a part of the imino group is alkylated. It is done. The residual ratio of imino groups in these molecules is preferably 20% or more and 50% or less, more preferably 25% or more and 45% or less, and further preferably 30% or more and 40% or less.

  As the alkylated polyalkylene guanidine, polyhexamethylene guanidine (“alkyl”) in which at least a part of the imino group is alkylated in view of the reactivity with the binder resin and the positive charge per unit mass. Polyhexamethylene guanidine ”) and acid addition salts thereof. As the acid addition salt, phosphate or hydrochloride is desirable.

-Alkylated polyalkyleneimine-
In this embodiment, the alkylated polyalkyleneimine is a polyalkyleneimine in which at least a part of the imino group is alkylated. The primary amino group (—NH ₂ ) in the molecule is preferably partially or entirely alkylated from the viewpoint of further suppressing the occurrence of image density unevenness.

  The alkylated polyalkyleneimine preferably has a residual ratio of imino groups in the molecule (number of imino groups ÷ total number of nitrogen atoms) of 20% or more and 50% or less. When the residual ratio is 50% or less, the generation of nitrogen oxides in the image forming apparatus is further suppressed, and the occurrence of uneven image density is further suppressed. When the residual ratio is 20% or more, the alkylated polyalkyleneimine tends to adhere to the surface of the toner particles, the positive charge amount of the toner is in a good range, and the occurrence of uneven image density is further suppressed. In view of the above, the remaining rate is more preferably 25% or more and 45% or less, and further preferably 30% or more and 40% or less.

  The alkyl group for alkylating the imino group is preferably an alkyl group having 1 to 12 carbon atoms, and more preferably an alkyl group having 1 to 6 carbon atoms. The alkyl group may be linear, branched, cyclic, or a combination of two or more selected from these. Specifically, for example, a linear alkyl group such as methyl group, ethyl group, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group, n-decyl, n-dodecyl; -Propyl group, iso-butyl group, sec-butyl group, tert-butyl group, iso-pentyl group, neopentyl group, tert-pentyl group, iso-hexyl group, sec-hexyl group, tert-hexyl group, etc. A cyclic alkyl group such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, and a cyclohexyl group.

  The alkylene group in the alkylated polyalkyleneimine molecule is preferably an alkylene group having 1 to 12 carbon atoms, and more preferably an alkylene group having 1 to 6 carbon atoms. The alkylene group may be any of linear, branched, cyclic, and combinations of two or more selected from these. Specifically, for example, methylene group, ethylene group, n-propylene group, n-butylene group, n-pentylene group, n-hexylene group (hexamethylene group), n-octalene group (octamethylene group), etc. Chain-like alkylene group: iso-propylene group, iso-butylene group, sec-butylene group, tert-butylene group, iso-pentylene group, neopentylene group, tert-pentylene group, iso-hexylene group, sec-hexylene group, tert A branched alkylene group such as a hexylene group; a cyclic alkylene group such as a cyclopropylene group, a cyclobutylene group, a cyclopentylene group, or a cyclohexylene group;

  Specific examples of the alkylated polyalkyleneimine include polyethyleneimine, polypropyleneimine, polybutyleneimine and the like in which at least a part of the imino group is alkylated. The residual ratio of imino groups in these molecules is preferably 20% or more and 50% or less, more preferably 25% or more and 45% or less, and further preferably 30% or more and 40% or less.

  The alkylated polyalkyleneimine is a polyethyleneimine in which at least a part of the imino group is alkylated (“alkylated polyethylene” in terms of good reactivity with the binder resin and a large amount of positive charge per unit mass. "Imin") is desirable.

  For example, the specific compound reacts an imine (polyalkylene biguanide, polyalkylene guanidine, or polyalkylene imine) with an alkyl halide or alkene to alkylate an imino group in the molecule of the imine (to the nitrogen atom). The bonded hydrogen atom is substituted with an alkyl group). Below, the example of the reaction scheme of alkylation of an imino group is shown. In the following chemical formula, X represents a halogen atom, and R represents an alkyl group.

  The amount of the specific compound on the surface of the toner particles is in the range of 0.0001 g or more and 0.0010 g or less per gram of the toner particles from the viewpoint of imparting an appropriate positive charge amount to the toner and further suppressing unevenness in image density. Desirably, a range of 0.0002 g or more and 0.0009 g or less is more preferable.

  The quantitative determination of the specific compound on the surface of the toner particles and the analysis of the imino group residual ratio are performed, for example, by the following method. The toner particles are hydrolyzed to obtain an extract containing the specific compound, and the specific compound in the extract is analyzed by infrared spectroscopy or nuclear magnetic resonance. The extract may be purified by column chromatography and then analyzed by infrared spectroscopy or nuclear magnetic resonance.

-Binder resin-
Examples of the binder resin include styrenes (for example, styrene, parachlorostyrene, α-methylstyrene, etc.), (meth) acrylic acid esters (for example, methyl (meth) acrylate, ethyl (meth) acrylate, (meth ) N-propyl acrylate, n-butyl (meth) acrylate, lauryl (meth) acrylate, 2-ethylhexyl (meth) acrylate), ethylenically unsaturated nitriles (eg (meth) acrylonitrile), vinyl ether Homopolymers (eg, vinyl methyl ether, vinyl isobutyl ether, etc.), vinyl ketones (eg, vinyl methyl ketone, vinyl ethyl ketone, vinyl isopropenyl ketone, etc.), olefins (eg, ethylene, propylene, butadiene, etc.) A polymer is mentioned.
Typical binder resins include, for example, polyester resins, epoxy resins, polyurethane resins, polyamide resins, cellulose resins, polyether resins, polystyrene, styrene- (meth) acrylic acid alkyl copolymers, styrene- (meth) acrylonitrile. Examples thereof include a copolymer, a styrene-butadiene copolymer, and a styrene-maleic anhydride copolymer.
These resins may be used alone or in combination of two or more.

  The content of the binder resin in the toner particles is preferably from 40% by weight to 95% by weight, more preferably from 50% by weight to 90% by weight, and even more preferably from 60% by weight to 85% by weight.

  A polyester resin is suitable as the binder resin. As a polyester resin, the condensation polymer of polyhydric carboxylic acid and polyhydric alcohol is mentioned, for example. As the polyester resin, a commercially available product may be used, or a synthesized resin may be used.

Examples of the polyvalent carboxylic acid include aliphatic dicarboxylic acids (eg, oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, alkenyl succinic acid, adipic acid, sebacic acid, etc.) Alicyclic dicarboxylic acids (for example, cyclohexanedicarboxylic acid), aromatic dicarboxylic acids (for example, terephthalic acid, isophthalic acid, phthalic acid, naphthalenedicarboxylic acid, etc.), their anhydrides, or lower (for example, having 1 or more carbon atoms) 5 or less) alkyl esters. Among these, as polyvalent carboxylic acid, aromatic dicarboxylic acid is preferable, for example.
The polyvalent carboxylic acid may be used in combination with a dicarboxylic acid or a trivalent or higher carboxylic acid having a crosslinked structure or a branched structure. Examples of the trivalent or higher carboxylic acid include trimellitic acid, pyromellitic acid, anhydrides thereof, or lower (eg, having 1 to 5 carbon atoms) alkyl ester.
A polyvalent carboxylic acid may be used individually by 1 type, and may use 2 or more types together.

Examples of the polyhydric alcohol include aliphatic diols (for example, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butanediol, hexanediol, neopentyl glycol, etc.), alicyclic diols (for example, cyclohexanediol, cyclohexanedimethanol, Hydrogenated bisphenol A, etc.) and aromatic diols (for example, ethylene oxide adducts of bisphenol A, propylene oxide adducts of bisphenol A, etc.). Among these, as the polyhydric alcohol, for example, aromatic diols and alicyclic diols are preferable, and aromatic diols are more preferable.
The polyhydric alcohol may be used in combination with a diol and a trivalent or higher alcohol having a crosslinked structure or a branched structure. Examples of the trivalent or higher alcohol include glycerin, trimethylolpropane, pentaerythritol and the like.
A polyhydric alcohol may be used individually by 1 type, and may use 2 or more types together.

The glass transition temperature (Tg) of the polyester resin is preferably 50 ° C. or higher and 80 ° C. or lower, and more preferably 50 ° C. or higher and 65 ° C. or lower.
The glass transition temperature is determined from a DSC curve obtained by differential scanning calorimetry (DSC). More specifically, it is determined by “extrapolated glass transition start temperature” described in JIS K7121-1987 “Method for Measuring Glass Transition Temperature”.

The weight average molecular weight (Mw) of the polyester resin is preferably from 5,000 to 1,000,000, and more preferably from 7,000 to 500,000.
The number average molecular weight (Mn) of the polyester resin is preferably 2,000 or more and 100,000 or less.
The molecular weight distribution Mw / Mn of the polyester resin is preferably 1.5 or more and 100 or less, and more preferably 2 or more and 60 or less.
The weight average molecular weight and number average molecular weight of the resin are measured by gel permeation chromatography (GPC). The molecular weight measurement by GPC is performed using HLC-8120 manufactured by Tosoh Corporation as a measuring apparatus, TSKgel SuperHM-M (15 cm) manufactured by Tosoh Corporation as a column, and tetrahydrofuran as a solvent. The weight average molecular weight and the number average molecular weight are calculated using a molecular weight calibration curve prepared from a monodisperse polystyrene standard sample from this measurement result.

-Colorant-
Examples of the colorant include carbon black, chrome yellow, hansa yellow, benzidine yellow, sren yellow, quinoline yellow, pigment yellow, permanent orange GTR, pyrazolone orange, vulcan orange, watch young red, permanent red, brilliantamine 3B, brilliant. Carmine 6B, Dupont Oil Red, Pyrazolone Red, Resol Red, Rhodamine B Lake, Lake Red C, Pigment Red, Rose Bengal, Aniline Blue, Ultramarine Blue, Calco Oil Blue, Methylene Blue Chloride, Phthalocyanine Blue, Pigment Blue, Phthalocyanine Green, Pigments such as malachite green oxalate; acridine, xanthene, azo, benzoquinone , Azine, anthraquinone, thioindigo, dioxazine, thiazine, azomethine, indigo dyes, phthalocyanine, aniline black, polymethine, triphenylmethane dyes, diphenylmethane dyes, dye thiazole like; and the like. A colorant may be used individually by 1 type and may use 2 or more types together.

  As the colorant, a surface-treated colorant may be used as necessary, or it may be used in combination with a dispersant.

  The content of the colorant is desirably 1% by mass or more and 30% by mass or less of the toner particles, and more desirably 3% by mass or more and 15% by mass or less.

-Release agent-
Examples of release agents include hydrocarbon waxes; natural waxes such as carnauba wax, rice wax, and candelilla wax; synthetic or mineral / petroleum waxes such as montan wax; and ester waxes such as fatty acid esters and montanic acid esters. And so on. The release agent is not limited to this.

The melting temperature of the release agent is preferably 50 ° C. or higher and 110 ° C. or lower, and more preferably 60 ° C. or higher and 100 ° C. or lower.
The melting temperature of the release agent is determined by the “melting peak temperature” described in the method for determining the melting temperature in JIS K7121-1987 “Method for measuring the transition temperature of plastic” from the DSC curve obtained by differential scanning calorimetry (DSC). Ask.

  The content of the release agent in the toner particles is preferably 1% by mass to 20% by mass, and more preferably 5% by mass to 15% by mass.

-Other additives-
Examples of other additives include known additives such as a magnetic material, a charge control agent, and inorganic powder. These additives are contained in the toner particles as internal additives.

-Toner particle characteristics-
The toner particles may be toner particles having a single layer structure, or toner particles having a so-called core / shell structure composed of a core (core particle) and a coating layer (shell layer) covering the core. May be.

  The volume average particle diameter (D50v) of the toner particles is preferably 2 μm or more and 10 μm or less, and more preferably 4 μm or more and 8 μm or less.

Various average particle diameters and various particle size distribution indexes of the toner particles are measured using Coulter Multisizer II (manufactured by Beckman-Coulter), and the electrolyte is measured using ISOTON-II (manufactured by Beckman-Coulter).
In the measurement, 0.5 mg to 50 mg of a measurement sample is added as a dispersant to 2 ml of a 5% aqueous solution of a surfactant (preferably sodium alkylbenzenesulfonate). This is added to 100 ml or more and 150 ml or less of the electrolytic solution.
The electrolyte in which the sample is suspended is dispersed for 1 minute with an ultrasonic disperser, and the particle size distribution of particles having a particle size in the range of 2 μm to 60 μm is obtained using a 100 μm aperture with a Coulter Multisizer II. taking measurement. The number of particles to be sampled is 50,000.
A cumulative distribution is drawn from the smaller diameter side to the particle size range (channel) divided based on the measured particle size distribution, and the cumulative particle size of 16% is the volume particle size D16v. D16p, the particle size that is 50% cumulative is defined as the volume average particle size D50v, the number average particle size D50p, and the particle size that is cumulative 84% is defined as the volume particle size D84v and the number particle size 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 .

  The shape factor SF1 of the toner particles is preferably 110 or more and 150 or less, and more preferably 120 or more and 140 or less.

The shape factor SF1 is obtained by the following equation.
Formula: SF1 = (ML ² / A) × (π / 4) × 100
In the above formula, ML represents the absolute maximum length of the toner, and A represents the projected area of the toner.
Specifically, the shape factor SF1 is quantified mainly by analyzing a microscope image or a scanning electron microscope image using an image analyzer, and is calculated as follows. That is, by capturing an optical microscope image of particles dispersed on the surface of a slide glass into a Luzex image analyzer using a video camera, obtaining the maximum length and projected area of 100 particles, calculating by the above formula, and obtaining the average value can get.

(External additive)
Examples of the external additive include inorganic particles. As the inorganic particles, SiO ₂ , TiO ₂ , Al ₂ O ₃ , CuO, ZnO, SnO ₂ , CeO ₂ , Fe ₂ O ₃ , MgO, BaO, CaO, K ₂ O, Na ₂ O, ZrO ₂ , CaO. _{SiO 2, K 2 O · (} TiO 2) n, Al 2 O 3 · 2SiO 2, CaCO 3, MgCO 3, BaSO 4, MgSO 4 , and the like.

The surface of the inorganic particles as an external additive is preferably subjected to a hydrophobic treatment. The hydrophobic treatment is performed, for example, by immersing inorganic particles in a hydrophobic treatment agent. The hydrophobizing agent is not particularly limited, and examples thereof include silane coupling agents, silicone oils, titanate coupling agents, aluminum coupling agents and the like. These may be used individually by 1 type and may use 2 or more types together.
The amount of the hydrophobizing agent is, for example, 1 part by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the inorganic particles.

  Examples of external additives include resin particles (resin particles such as polystyrene, PMMA, and melamine resin), cleaning activators (for example, metal salts of higher fatty acids typified by zinc stearate, particles of a fluorine-based high molecular weight substance), and the like. Can be mentioned.

  The external additive amount of the external additive is, for example, preferably 0.01% by mass or more and 5% by mass or less, and more preferably 0.01% by mass or more and 2% by mass or less with respect to the toner particles.

[Toner Production Method]
Hereinafter, the toner particles before surface modification may be referred to as “toner mother particles”.

  The toner according to the exemplary embodiment may be produced by producing toner particles, and the toner particles may be used as a toner, or an external additive may be externally added to the toner particles. The toner particles can be produced by producing toner mother particles and surface-modifying the toner mother particles with a specific compound.

  The toner base particles may be produced by any of a dry production method (for example, a kneading pulverization method) and a wet production method (for example, an aggregation coalescence method, a suspension polymerization method, a dissolution suspension method, etc.). There is no restriction | limiting in particular in these manufacturing methods, A well-known manufacturing method is employ | adopted. Among these, it is preferable to obtain toner mother particles by an aggregation coalescence method. When toner base particles produced by the aggregation coalescence method are used, the distribution of specific compounds on the surface of the toner base particles is less biased during toner manufacture because the particle size distribution is narrow and the particle surface is highly smooth. There is little bias in the charging of particles.

When the toner base particles are produced by the aggregation and coalescence method, specifically, for example,
A step of preparing a resin particle dispersion in which resin particles to be a binder resin are dispersed (resin particle dispersion preparation step); and a dispersion in which other particle dispersions are also mixed in the resin particle dispersion (if necessary) A process of aggregating resin particles (and other particles as necessary) to form aggregated particles (aggregated particle formation process); heating the aggregated particle dispersion in which the aggregated particles are dispersed, and aggregating The toner base particles are manufactured through a step of fusing and coalescing the particles to form toner particles (fusing and coalescence step).

  Details of each step will be described below. In the following description, a method for obtaining toner base particles containing a colorant and a release agent will be described. The colorant and the release agent are used as necessary. Of course, you may use other additives other than a coloring agent and a mold release agent.

-Preparation step of resin particle dispersion-
First, for example, a colorant dispersion in which colorant particles are dispersed and a release agent dispersion in which release agent particles are dispersed are prepared together with a resin particle dispersion in which resin particles to be a binder resin are dispersed.

  The resin particle dispersion is prepared, for example, by dispersing resin particles in a dispersion medium using a surfactant.

Examples of the dispersion medium used for the resin particle dispersion include an aqueous medium.
Examples of the aqueous medium include water such as distilled water and ion exchange water, and alcohols. These may be used individually by 1 type and may use 2 or more types together.

Examples of the surfactant include anionic surfactants such as sulfate ester, sulfonate, phosphate, and soap; cationic surfactants such as amine salt type and quaternary ammonium salt type; polyethylene glycol And nonionic surfactants such as polyphenols, alkylphenol ethylene oxide adducts, and polyhydric alcohols. Among these, an anionic surfactant and a cationic surfactant are particularly mentioned. The nonionic surfactant may be used in combination with an anionic surfactant or a cationic surfactant.
Surfactant may be used individually by 1 type and may use 2 or more types together.

Examples of the method for dispersing the resin particles in the dispersion medium in the resin particle dispersion include general dispersion methods such as a rotary shear type homogenizer, a ball mill having a medium, a sand mill, and a dyno mill. Depending on the type of resin particles, the resin particles may be dispersed in the resin particle dispersion using, for example, a phase inversion emulsification method.
In the phase inversion emulsification method, a resin to be dispersed is dissolved in a hydrophobic organic solvent in which the resin is soluble, a base is added to the organic continuous phase (O phase), and the aqueous medium (W In this method, the resin is converted from W / O to O / W (so-called phase inversion) to form a discontinuous phase, and the resin is dispersed in the form of particles in an aqueous medium. .

The volume average particle size of the resin particles dispersed in the resin particle dispersion is preferably 0.01 μm or more and 1 μm or less, more preferably 0.08 μm or more and 0.8 μm or less, further 0.1 μm or more and 0.6 μm or less. preferable.
The volume average particle size of the resin particles is a volume with respect to a divided particle size range (channel) using a particle size distribution obtained by measurement with a laser diffraction particle size distribution measuring apparatus (for example, LA-700 manufactured by HORIBA, Ltd.). The cumulative distribution is drawn from the small particle diameter side, and the particle diameter that becomes 50% cumulative with respect to all particles is defined as the volume average particle diameter D50v. The volume average particle size of the particles in the other dispersion is also measured in the same manner.

  5 mass% or more and 50 mass% or less are preferable, and, as for content of the resin particle contained in the resin particle dispersion liquid, 10 mass% or more and 40 mass% or less are more preferable.

  Similar to the resin particle dispersion, for example, a colorant dispersion and a release agent dispersion are also prepared. That is, the dispersion medium, the dispersion method, the volume average particle diameter of the particles, and the content of the particles in the resin particle dispersion are the same in the colorant dispersion and the release agent dispersion.

-Aggregated particle formation process-
Next, the colorant dispersion and the release agent dispersion are mixed together with the resin particle dispersion.
Then, in the mixed dispersion, resin particles, colorant particles, and release agent particles are hetero-aggregated to have resin particles, colorant particles, and release agent particles having a diameter close to the diameter of the target toner particles. Aggregated particles are formed.

Specifically, for example, a flocculant is added to the mixed dispersion, and the pH of the mixed dispersion is adjusted to acidic (for example, pH 2 to 5), and a dispersion stabilizer is added as necessary. The glass particles are heated to a temperature close to the glass transition temperature (specifically, for example, the glass transition temperature of the resin particles is −30 ° C. or higher and the glass transition temperature is −10 ° C. or lower), and the particles dispersed in the mixed dispersion are agglomerated. To form aggregated particles.
In the agglomerated particle forming step, for example, the agglomerated agent is added at room temperature (for example, 25 ° C.) while stirring the mixed dispersion with a rotary shearing homogenizer, and the pH of the mixed dispersion is adjusted to be acidic (for example, pH 2 to 5). In addition, heating may be performed after adding a dispersion stabilizer as necessary.

Examples of the flocculant include a surfactant having a polarity opposite to that of the surfactant contained in the mixed dispersion, such as an inorganic metal salt and a bivalent or higher-valent metal complex. When a metal complex is used as the flocculant, the amount of the flocculant used is reduced and the charging characteristics are improved.
An additive that forms a complex or similar bond with the metal ion of the flocculant may be used together with the flocculant. As this additive, a chelating agent is preferably used.

Examples of inorganic metal salts include metal salts such as calcium chloride, calcium nitrate, barium chloride, magnesium chloride, zinc chloride, aluminum chloride, and aluminum sulfate; inorganic metal salts such as polyaluminum chloride, polyaluminum hydroxide, and calcium polysulfide Polymer; and the like.
A water-soluble chelating agent may be used as the chelating agent. Examples of the chelating agent include oxycarboxylic acids such as tartaric acid, citric acid, and gluconic acid; aminocarboxylic acids such as iminodiacetic acid (IDA), nitrilotriacetic acid (NTA), and ethylenediaminetetraacetic acid (EDTA); .
For example, the addition amount of the chelating agent is preferably 0.01 parts by mass or more and 5.0 parts by mass or less, and more preferably 0.1 parts by mass or more and less than 3.0 parts by mass with respect to 100 parts by mass of the resin particles.

-Fusion / unification process-
Next, the agglomerated particle dispersion in which the agglomerated particles are dispersed is heated to, for example, a glass transition temperature or higher of the resin particles (for example, a temperature of 10 ° C. to 30 ° C. higher than the glass transition temperature of the resin particles). Are fused and united to form toner base particles.

Through the above steps, toner base particles are obtained.
In addition, after obtaining the aggregated particle dispersion liquid in which the aggregated particles are dispersed, the aggregated particle dispersion liquid and the resin particle dispersion liquid in which the resin particles are dispersed are further mixed, and the resin particles are further added to the surface of the aggregated particles. A process of aggregating to adhere to form second aggregated particles, and heating the second aggregated particle dispersion in which the second aggregated particles are dispersed to fuse and coalesce the second aggregated particles. The toner mother particles may be manufactured through a step of forming toner mother particles having a core / shell structure.

  After the coalescence and coalescence process, it is desirable to perform a washing process on the toner base particles formed in the solution. In the washing step, it is preferable to sufficiently perform substitution washing with ion-exchanged water from the viewpoint of chargeability.

  Toner base particles produced by a dry process or a wet process are subjected to a surface modification treatment with a specific compound. The said surface modification process is performed by the following surface modification processes, for example.

-Surface modification process-
The surface modification step is, for example, a step of mixing an aqueous dispersion containing toner base particles and a specific compound.

  It is desirable to adjust the pH of the aqueous dispersion to 4 to 8. Accordingly, the reaction between the acidic group present on the surface of the toner base particle and the basic group of the specific compound can be efficiently advanced while suppressing unintentional alteration of the constituent material of the toner base particle. The pH of the aqueous dispersion is adjusted, for example, by adding 1N hydrochloric acid or nitric acid.

  In the surface modification step, it is desirable to stir the mixture of the aqueous dispersion and the specific compound for 10 minutes to 1 hour. Thereby, the toner base particle surface can be modified more uniformly. The temperature of the mixed solution at the time of stirring is, for example, 15 ° C. to 25 ° C., and may be performed while heating the mixed solution to 25 ° C. to 40 ° C.

  The amount of the specific compound used in the surface modification step is desirably 0.01 parts by mass to 0.1 parts by mass with respect to 100 parts by mass of the particles. When the amount of the specific compound used is within the above range, problems such as elution of the specific compound from the surface-modified toner particles can be suppressed, and the positive charge amount of the toner can be adjusted to a favorable range.

  After the surface modification step and the alkylation step, the surface-modified toner particles are subjected to a washing step, a solid-liquid separation step, and a drying step to obtain dried toner particles. In the washing step, it is preferable to sufficiently perform substitution washing with ion-exchanged water from the viewpoint of chargeability. The solid-liquid separation step is not particularly limited, but suction filtration, pressure filtration, or the like is preferably performed from the viewpoint of productivity. Also, the drying process is not particularly limited, but from the viewpoint of productivity, freeze drying, flash jet drying, fluidized drying, vibration fluidized drying, or the like is preferably performed.

  The toner according to the exemplary embodiment is manufactured, for example, by adding an external additive to dry toner particles and mixing them. Mixing is preferably performed by, for example, a V blender, a Henschel mixer, a Ladyge mixer, or the like. Furthermore, if necessary, coarse toner particles may be removed using a vibration classifier, a wind classifier, or the like.

<Electrostatic image developer>
The electrostatic charge image developer according to the exemplary embodiment includes at least the toner according to the exemplary embodiment. The electrostatic charge image developer according to this embodiment may be a one-component developer including only the toner according to this embodiment, or may be a two-component developer in which the toner and a carrier are mixed.
The toner according to this embodiment is preferably a non-magnetic one-component toner, that is, the electrostatic charge image developer according to this embodiment is a non-magnetic one-component developer including the toner according to this embodiment. desirable.

  When the electrostatic charge image developer according to the exemplary embodiment is a two-component developer, the mixing ratio of the toner and the carrier (toner: carrier, mass ratio) is preferably 1: 100 to 30: 100, and 3: 100 to 20: 100 is more preferable. A known carrier may be used as the carrier.

<Image Forming Apparatus / Image Forming Method>
An image forming apparatus and an image forming method according to the present embodiment will be described.
The image forming apparatus according to the present embodiment includes an image carrier, a charging unit that charges the surface of the image carrier, an electrostatic image forming unit that forms an electrostatic image on the surface of the charged image carrier, and an electrostatic charge. Development means for containing an image developer and developing the electrostatic image formed on the surface of the image carrier as a toner image with the electrostatic image developer, and the toner image formed on the surface of the image carrier as a recording medium Transfer means for transferring to the surface of the recording medium, and fixing means for fixing the toner image transferred to the surface of the recording medium. The electrostatic charge image developer according to this embodiment is applied as the electrostatic charge image developer.

  In the image forming apparatus according to this embodiment, a charging process for charging the surface of the image carrier, an electrostatic charge image forming process for forming an electrostatic image on the surface of the charged image carrier, and an electrostatic charge according to this embodiment. A developing step of developing an electrostatic charge image formed on the surface of the image carrier as a toner image with an image developer; a transfer step of transferring the toner image formed on the surface of the image carrier to the surface of the recording medium; An image forming method (an image forming method according to the present embodiment) including a fixing step of fixing the toner image transferred onto the surface of the recording medium is performed.

The image forming apparatus according to the present embodiment is a direct transfer type apparatus that directly transfers a toner image formed on the surface of an image carrier to a recording medium; the toner image formed on the surface of the image carrier is transferred to an intermediate transfer member An intermediate transfer type apparatus that primarily transfers the toner image transferred to the surface of the intermediate transfer body and then secondary transfer the toner image to the surface of the recording medium; after the toner image is transferred, the surface of the image carrier before charging is cleaned. A known image forming apparatus such as an apparatus provided with a cleaning unit; an apparatus provided with a charge removing unit that discharges the surface of the image holding member with a discharge light before charging after transferring the toner image;
In the case where the image forming apparatus according to this embodiment is an intermediate transfer type apparatus, for example, the transfer unit intermediately transfers an intermediate transfer body on which a toner image is transferred onto the surface and a toner image formed on the surface of the image holding body. A configuration having primary transfer means for primary transfer onto the surface of the body and secondary transfer means for secondary transfer of the toner image transferred onto the surface of the intermediate transfer body onto the surface of the recording medium is applied.

  In the image forming apparatus according to the present embodiment, for example, the part including the developing unit may have a cartridge structure (process cartridge) that is detachable from the image forming apparatus. As the process cartridge, for example, a process cartridge that accommodates the electrostatic charge image developer according to this embodiment and includes a developing unit is preferably used.

  Hereinafter, an example of the image forming apparatus according to the present embodiment will be described, but the present invention is not limited to this. In the following description, the main part shown in the figure will be described, and the description of other parts will be omitted.

FIG. 1 is a schematic configuration diagram illustrating an image forming apparatus according to the present embodiment.
The image forming apparatus shown in FIG. 1 is a first electrophotographic system that outputs an image of each color of yellow (Y), magenta (M), cyan (C), and black (K) based on color-separated image data. To fourth image forming units 10Y, 10M, 10C, and 10K (image forming means). These image forming units (hereinafter sometimes simply referred to as “units”) 10Y, 10M, 10C, and 10K are arranged in parallel at a predetermined distance from each other in the horizontal direction. These units 10Y, 10M, 10C, and 10K may be process cartridges that can be attached to and detached from the image forming apparatus.

Above each unit 10Y, 10M, 10C, 10K, an intermediate transfer belt (an example of an intermediate transfer member) 20 is extended through each unit. The intermediate transfer belt 20 is provided around a drive roll 22 and a support roll 24 that are in contact with the inner surface of the intermediate transfer belt 20, and travels in a direction from the first unit 10Y to the fourth unit 10K. Yes. A force is applied to the support roll 24 in a direction away from the drive roll 22 by a spring or the like (not shown), and tension is applied to the intermediate transfer belt 20 wound around the support roll 24. An intermediate transfer body cleaning device 30 is provided on the image holding surface side of the intermediate transfer belt 20 so as to face the drive roll 22.
Each unit 10Y, 10M, 10C, 10K developing device (an example of developing means) 4Y, 4M, 4C, 4K has yellow, magenta, cyan, black in toner cartridges 8Y, 8M, 8C, 8K, respectively. Each toner is supplied.

  Since the first to fourth units 10Y, 10M, 10C, and 10K have the same configuration, operation, and action, the yellow image disposed upstream in the intermediate transfer belt traveling direction is displayed here. The first unit 10Y to be formed will be described as a representative.

The first unit 10Y has a photoreceptor 1Y that functions as an image holding member. Around the photoreceptor 1Y, a charging roll (an example of a charging unit) 2Y for charging the surface of the photoreceptor 1Y to a predetermined potential, and the charged surface is exposed by a laser beam 3Y based on a color-separated image signal. Then, an exposure device (an example of an electrostatic image forming unit) 3 that forms an electrostatic image, and a developing device (an example of a developing unit) 4Y that develops the electrostatic image by supplying toner charged to the electrostatic image, developed A primary transfer roll (an example of a primary transfer unit) 5Y that transfers a toner image onto the intermediate transfer belt 20, and a photoconductor cleaning device (an example of a cleaning unit) 6Y that removes toner remaining on the surface of the photoconductor 1Y after the primary transfer. Are arranged in order.
The primary transfer roll 5Y is disposed inside the intermediate transfer belt 20, and is provided at a position facing the photoreceptor 1Y. A bias power source (not shown) for applying a primary transfer bias is connected to the primary transfer rolls 5Y, 5M, 5C, and 5K of each unit. Each bias power source changes the value of the transfer bias applied to each primary transfer roll under the control of a control unit (not shown).

Hereinafter, an operation of forming a yellow image in the first unit 10Y will be described.
First, prior to the operation, the surface of the photoreceptor 1Y is charged to a potential of + 600V to + 800V by the charging roll 2Y.
The photoreceptor 1Y is formed by laminating a photosensitive layer on a conductive base (for example, a volume resistivity of 1 × 10 ⁻⁶ Ωcm or less at 20 ° C.). This photosensitive layer usually has a high resistance (general resin resistance), but has a property of changing the specific resistance of the portion irradiated with the laser beam when irradiated with the laser beam. Therefore, the laser beam 3Y is irradiated from the exposure device 3 on the surface of the charged photoreceptor 1Y in accordance with yellow image data sent from a control unit (not shown). Thereby, an electrostatic charge image of a yellow image pattern is formed on the surface of the photoreceptor 1Y.

The electrostatic charge image is an image formed on the surface of the photoreceptor 1Y by charging, and the specific resistance of the irradiated portion of the photosensitive layer is lowered by the laser beam 3Y, and the charged charge on the surface of the photoreceptor 1Y flows. On the other hand, this is a so-called negative latent image formed by the charge remaining in the portion not irradiated with the laser beam 3Y.
The electrostatic charge image formed on the photoreceptor 1Y rotates to a predetermined development position as the photoreceptor 1Y travels. At this development position, the electrostatic charge image on the photoreceptor 1Y is developed and visualized as a toner image by the developing device 4Y.

In the developing device 4Y, an electrostatic charge image developer containing yellow toner is accommodated in the case of a one-component developer, and an electrostatic charge image developer containing yellow toner and a carrier is accommodated in the case of a two-component developer. Yes. The toner according to the exemplary embodiment is positively charged by having a specific compound on the surface of the toner particles, but may be further frictionally charged. That is, in the case of a one-component developer, the yellow toner may be frictionally charged on the developing roll by friction with a regulating member that regulates the thickness of the developing roll or the toner layer. In the case of a two-component developer, the yellow toner may be frictionally charged by stirring together with the carrier inside the developing device 4Y. In any case, the yellow toner has the same polarity (positive polarity) as that of the surface of the photoreceptor 1Y and is held on the developing roll.
Then, as the surface of the photoreceptor 1Y passes through the developing device 4Y, the yellow toner is electrostatically attached to the latent image portion on the surface of the photoreceptor 1Y, and the latent image is developed with the yellow toner. The The photoreceptor 1Y on which the yellow toner image is formed continues to run at a predetermined speed, and the toner image developed on the photoreceptor 1Y is conveyed to a predetermined primary transfer position.

When the yellow toner image on the photoreceptor 1Y is transported to the primary transfer position, a primary transfer bias is applied to the primary transfer roll 5Y, and electrostatic force from the photoreceptor 1Y toward the primary transfer roll 5Y acts on the toner image. The toner image on the photoreceptor 1Y is transferred onto the intermediate transfer belt 20. The transfer bias applied at this time has a negative polarity (−) opposite to the polarity (+) of the toner, and is controlled to, for example, −10 μA by the control unit (not shown) in the first unit 10Y.
On the other hand, the toner remaining on the photoreceptor 1Y is removed and collected by the photoreceptor cleaning device 6Y.

The primary transfer bias applied to the primary transfer rolls 5M, 5C, and 5K after the second unit 10M is also controlled according to the first unit.
Thus, the intermediate transfer belt 20 onto which the yellow toner image has been transferred by the first unit 10Y is sequentially conveyed through the second to fourth units 10M, 10C, and 10K, and the toner images of the respective colors are superimposed and transferred in a multiple manner. The

  The intermediate transfer belt 20 onto which the four color toner images have been transferred in multiple ways through the first to fourth units includes the intermediate transfer belt 20, a support roll 24 in contact with the inner surface of the intermediate transfer belt, and an image holding surface of the intermediate transfer belt 20. To a secondary transfer portion composed of a secondary transfer roll (an example of secondary transfer means) 26 arranged on the side. On the other hand, recording paper (an example of a recording medium) P is fed at a predetermined timing into a gap where the secondary transfer roll 26 and the intermediate transfer belt 20 are in contact with each other via a supply mechanism, and the secondary transfer bias is supplied to the support roll. 24. The transfer bias applied at this time is a (+) polarity that is the same polarity as the polarity (+) of the toner, and an electrostatic force from the intermediate transfer belt 20 toward the recording paper P acts on the toner image, and the transfer bias is applied to the intermediate transfer belt 20. The toner image is transferred onto the recording paper P. The secondary transfer bias at this time is determined according to the resistance detected by a resistance detecting means (not shown) for detecting the resistance of the secondary transfer portion, and is voltage-controlled.

  Thereafter, the recording paper P is sent to a pressure contact portion (nip portion) of a pair of fixing rolls in a fixing device (an example of a fixing unit) 28, and the toner image is fixed on the recording paper P to form a fixed image. .

Examples of the recording paper P to which the toner image is transferred include plain paper used in electrophotographic copying machines, printers, and the like. As the recording medium, in addition to the recording paper P, an OHP sheet and the like are also included.
In order to further improve the smoothness of the image surface after fixing, it is preferable that the surface of the recording paper P is also smooth. For example, coated paper in which the surface of plain paper is coated with resin, art paper for printing, etc. Preferably used.

  The recording paper P on which the color image has been fixed is carried out toward the discharge unit, and a series of color image forming operations is completed.

<Process cartridge / toner cartridge>
The process cartridge according to this embodiment will be described.
The process cartridge according to the present embodiment accommodates the electrostatic image developer according to the present embodiment, and develops the electrostatic image formed on the surface of the image carrier as a toner image by the electrostatic image developer. And a process cartridge that can be attached to and detached from the image forming apparatus.

  The process cartridge according to the present embodiment is not limited to the above configuration, and is selected from a developing device and other means such as an image carrier, a charging unit, an electrostatic charge image forming unit, and a transfer unit, if necessary. And at least one of the above may be provided.

  Hereinafter, an example of the process cartridge according to the present embodiment will be shown, but the present invention is not limited to this. In the following description, the main part shown in the figure will be described, and the description of other parts will be omitted.

FIG. 2 is a schematic configuration diagram showing a process cartridge according to the present embodiment.
The process cartridge 200 shown in FIG. 2 is provided around the photoconductor 107 and the photoconductor 107 by, for example, a housing 117 provided with an attachment rail 116 and an opening 118 for exposure. A charging roller 108 (an example of a charging unit), a developing device 111 (an example of a developing unit), and a photoconductor cleaning device 113 (an example of a cleaning unit) are integrally combined and held to form a cartridge. Yes.
In FIG. 2, 109 is an exposure device (an example of an electrostatic charge image forming unit), 112 is a transfer device (an example of a transfer unit), 115 is a fixing device (an example of a fixing unit), and 300 is a recording paper (an example of a recording medium). Is shown.

Next, the toner cartridge according to this embodiment will be described.
The toner cartridge according to the present exemplary embodiment is a toner cartridge that accommodates the toner according to the present exemplary embodiment and is detachable from the image forming apparatus. The toner cartridge contains toner for replenishment to be supplied to the developing means provided in the image forming apparatus.

  The image forming apparatus shown in FIG. 1 is an image forming apparatus having a configuration in which toner cartridges 8Y, 8M, 8C, and 8K are attached and detached. The developing devices 4Y, 4M, 4C, and 4K are toner cartridges corresponding to respective colors. And a toner supply pipe (not shown). Further, when the amount of toner stored in the toner cartridge becomes low, the toner cartridge is replaced.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples unless it exceeds the gist thereof.

  In the following, “part” is based on mass unless otherwise specified.

[Preparation of resin particle dispersion (1)]
・ Terephthalic acid: 30 mol part ・ Fumaric acid: 70 mol part ・ Bisphenol A ethylene oxide adduct: 5 mol part ・ Bisphenol A propylene oxide adduct: 95 mol part Stirrer, nitrogen introduction tube, temperature sensor, and rectifying column The above material was charged into a 5 liter flask equipped with the above, the temperature was raised to 220 ° C. over 1 hour, and 1 part of titanium tetraethoxide was added to 100 parts of the material. The temperature was raised to 230 ° C. over 0.5 hours while distilling off the produced water, and the dehydration condensation reaction was continued at that temperature for 1 hour, and then the reaction product was cooled. Thus, a polyester resin (1) having a weight average molecular weight of 18,000, an acid value of 15 mgKOH / g, and a glass transition temperature of 60 ° C. was synthesized.

In a container equipped with temperature control means and nitrogen replacement means, 40 parts of ethyl acetate and 25 parts of 2-butanol are added to make a mixed solvent, and then 100 parts of polyester resin (1) is gradually added and dissolved therein. A 10% by mass aqueous ammonia solution (corresponding to 3 times the molar ratio with respect to the acid value of the resin) was added and stirred for 30 minutes.
Next, the inside of the container was replaced with dry nitrogen, the temperature was kept at 40 ° C., and 400 parts of ion-exchanged water was added dropwise at a rate of 2 parts / minute while stirring the mixed solution to carry out emulsification. After completion of the dropwise addition, the emulsion is returned to room temperature (20 ° C. to 25 ° C.), and stirred for 48 hours with dry nitrogen to reduce ethyl acetate and 2-butanol to 1,000 ppm or less. A resin particle dispersion in which resin particles having a diameter of 200 nm were dispersed was obtained. Ion exchange water was added to the resin particle dispersion to adjust the solid content to 30% by mass to obtain a resin particle dispersion (1).

[Preparation of resin particle dispersion (2)]
Styrene: 310 parts n-butyl acrylate: 100 parts β-carboxyethyl acrylate: 9 parts 1,10-decanediol diacrylate: 1.5 parts Dodecanethiol: 3 parts Anionic surfactant in the flask (Dow Fax manufactured by Dow Chemical Co., Ltd.) A solution in which 4 parts were dissolved in 550 parts of ion-exchanged water was added, and a mixed liquid in which the above materials were mixed was added to emulsify. While slowly stirring the emulsion for 10 minutes, 50 parts of ion-exchanged water in which 6 parts of ammonium persulfate had been dissolved was added. Next, after sufficiently replacing the nitrogen in the system, the flask was heated with an oil bath while stirring until the temperature in the system reached 75 ° C., and the emulsion polymerization was continued for 4 hours as it was. As a result, a resin particle dispersion in which resin particles having a weight average molecular weight of 33,000, a glass transition temperature of 53 ° C., and a volume average particle size of 250 nm were dispersed was obtained. Ion exchange water was added to the resin particle dispersion to adjust the solid content to 30% by mass to obtain a resin particle dispersion (2).

(Preparation of release agent dispersion)
-Paraffin wax (HNP-9 manufactured by Nippon Seiwa Co., Ltd.): 50 parts-Anionic surfactant (Neogen RK, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.): 1 part-Ion-exchanged water: 200 parts And then dispersed using a homogenizer (Ultra Turrax T50 manufactured by IKA) and then dispersed using a Menton Gorin high-pressure homogenizer (manufactured by Gorin) to release the release agent particles having a volume average particle diameter of 200 nm. A mold dispersion (solid content 20% by mass) was prepared.

(Preparation of colorant dispersion)
Carbon black (Regal 330 manufactured by Cabot): 50 parts Anionic surfactant (Neogen RK manufactured by Daiichi Kogyo Seiyaku Co., Ltd.): 1 part Ion-exchanged water: 200 parts The above materials were mixed and homogenizer (Ultra manufactured by IKA) A colorant dispersion (solid content 20% by mass) in which colorant particles having a volume average particle diameter of 180 nm were dispersed was prepared by dispersing for 10 minutes using TALAX T50).

[Preparation of toner base particles (1)]
-Resin particle dispersion (1): 480 parts-Release agent dispersion: 70 parts-Colorant dispersion: 50 parts-Charge control agent (20 mass% aqueous dispersion of Bontron P-51 manufactured by Orient Chemical Co., Ltd.): 10 parts anionic surfactant (TeycaPower, 20% by mass aqueous solution manufactured by Teika): 2 parts The above materials were placed in a round stainless steel flask and dispersed using a homogenizer (Ultra Turrax T50, manufactured by IKA). Subsequently, 0.1N nitric acid was added to adjust the pH to 3.5, and 30 parts of an aqueous nitric acid solution having a polyaluminum chloride concentration of 10% by mass was added. Subsequently, after dispersing at 30 ° C. using a homogenizer, the mixture was heated to 40 ° C. in a heating oil bath and held for 30 minutes. Thereafter, 100 parts of the resin particle dispersion (1) was gently added and held for 30 minutes. Then, after adding 0.1N sodium hydroxide aqueous solution and adjusting pH to 8.5, it heated to 85 degreeC, continuing stirring, and hold | maintained for 180 minutes. After confirming that the aggregated particles were fused with an optical microscope, it was cooled to 20 ° C. at a rate of 1 ° C./min. After cooling, the particles were separated by filtration, sufficiently washed with ion exchange water, and dried to obtain toner base particles (1) having a volume average particle diameter of 7 μm.

[Preparation of toner base particles (2)]
Toner base particles (2) having a volume average particle diameter of 7 μm were prepared in the same manner as toner base particles (1) except that resin particle dispersion liquid (2) was used instead of resin particle dispersion liquid (1). .

<Example A1>
Pentylated polyhexamethylene biguanide was prepared by reacting 100 parts of polyhexamethylene biguanide with 38 parts of 1-chloropentane. The residual ratio of imino groups was 35%.

  The toner base particles (1) were dispersed in ion-exchanged water so that the solid content was 30% by mass, and the pH was adjusted to 5.0 by adding 1N nitric acid. While stirring this dispersion, a pentylated polyhexamethylene biguanide aqueous solution was added dropwise thereto. The pentylated polyhexamethylene biguanide was added to 0.08 parts with respect to 100 parts of the toner base particles. After stirring for 20 minutes with a stirring blade, the dispersion was subjected to solid-liquid separation, and further, re-dispersion in ion-exchanged water and solid-liquid separation were repeated for washing treatment. When the pH of the filtrate reached 7.5, the washing treatment was terminated, and the solid content was dried with a vacuum dryer for 12 hours to obtain toner particles having a volume average particle diameter of 7 μm.

  Toner (nonmagnetic one-component developer) was obtained by mixing 100 parts of toner particles and 2 parts of NA50Y (fumed silica treated with silicone oil and aminosilane) by Nippon Aerosil Co., Ltd. using a Henschel mixer.

<Examples A2 to A5>
In Example A2, 1-chloropentane was 24 parts, in Example A3 1-chloropentane was 32 parts, in Example A4 1-chloropentane was 44 parts, and in Example A5 1-chloropentane was 53 parts. In addition, a toner was obtained in the same manner as in Example A1, except that each was changed.

<Examples A6 to A8>
In Example A6, a toner was obtained in the same manner as in Example A1 except that 36 parts of 1-chloropentane and 0.024 parts of pentylated polyhexamethylene biguanide with respect to 100 parts of toner base particles were used.
In Example A7, a toner was obtained in the same manner as in Example A1 except that 40 parts of 1-chloropentane and 0.15 parts of pentylated polyhexamethylene biguanide with respect to 100 parts of toner base particles were used.
In Example A8, a toner was obtained in the same manner as in Example A1, except that 38 parts of 1-chloropentane was used and toner base particles (2) were used instead of toner base particles (1).

<Example A9>
A toner was obtained in the same manner as in Example A1, except that pentylated polyhexamethylene biguanide was replaced with ethylated polyhexamethylene biguanide. The ethylated polyhexamethylene biguanide used here was prepared by reacting 100 parts of polyhexamethylene biguanide with 23 parts of chloroethane. The residual ratio of imino groups was 34%.

<Comparative Example A1>
A toner was obtained in the same manner as in Example A1, except that the polyhexamethylene biguanide used in the preparation of the pentylated polyhexamethylene biguanide in Example A1 was used without being alkylated.

<Example B1>
Pentylated polyhexamethylene guanidine was prepared by reacting 100 parts of polyhexamethylene guanidine with 38 parts of 1-chloropentane. The residual ratio of imino groups was 34%.

  The toner base particles (1) were dispersed in ion-exchanged water so that the solid content was 30% by mass, and the pH was adjusted to 5.0 by adding 1N nitric acid. While stirring this dispersion, a pentylated polyhexamethyleneguanidine aqueous solution was added dropwise thereto. The pentylated polyhexamethylene guanidine was added to 0.08 parts with respect to 100 parts of the toner base particles. After stirring for 20 minutes with a stirring blade, the dispersion was subjected to solid-liquid separation, and further, re-dispersion in ion-exchanged water and solid-liquid separation were repeated for washing treatment. When the pH of the filtrate reached 7.5, the washing treatment was terminated, and the solid content was dried with a vacuum dryer for 12 hours to obtain toner particles having a volume average particle diameter of 7 μm.

  Toner (nonmagnetic one-component developer) was obtained by mixing 100 parts of toner particles and 2 parts of NA50Y (fumed silica treated with silicone oil and aminosilane) by Nippon Aerosil Co., Ltd. using a Henschel mixer.

<Examples B2 to B5>
In Example B2, 1-chloropentane is 25 parts, in Example B3 1-chloropentane is 30 parts, in Example B4 1-chloropentane is 45 parts, in Example B5 1-chloropentane is 49 parts. In addition, a toner was obtained in the same manner as in Example B1, except that each was changed.

<Examples B6 to B8>
In Example B6, a toner was obtained in the same manner as in Example B1, except that 1-chloropentane was 39 parts and pentylated polyhexamethylene guanidine was 0.024 parts with respect to 100 parts of toner base particles.
In Example B7, a toner was obtained in the same manner as in Example B1, except that 1-chloropentane was changed to 37 parts and pentylated polyhexamethyleneguanidine was changed to 0.15 parts with respect to 100 parts of the toner base particles.
In Example B8, a toner was obtained in the same manner as in Example B1 except that 38 parts of 1-chloropentane was used and the toner base particles (2) were used instead of the toner base particles (1).

<Example B9>
A toner was obtained in the same manner as in Example B1, except that pentylated polyhexamethylene guanidine was replaced with ethylated polyhexamethylene guanidine. The ethylated polyhexamethylene guanidine used here was prepared by reacting 100 parts of polyhexamethylene guanidine with 22 parts of chloroethane. The residual ratio of imino groups was 37%.

<Comparative Example B1>
A toner was obtained in the same manner as in Example B1, except that the polyhexamethylene guanidine used in the preparation of the pentylated polyhexamethylene guanidine in Example B1 was used without being alkylated.

<Example C1>
Pentylated polyethyleneimine was prepared by reacting 100 parts of polyethyleneimine with 37 parts of 1-chloropentane. The residual ratio of imino groups was 36%.

  The toner base particles (1) were dispersed in ion-exchanged water so that the solid content was 30% by mass, and 1N hydrochloric acid was added to adjust the pH to 4.0. While stirring this dispersion, a pentylated polyethyleneimine aqueous solution was added dropwise thereto. The pentylated polyethyleneimine was added to 0.08 part with respect to 100 parts of toner base particles. After stirring for 20 minutes with a stirring blade, the dispersion was subjected to solid-liquid separation, and further, re-dispersion in ion-exchanged water and solid-liquid separation were repeated for washing treatment. When the pH of the filtrate reached 7.5, the washing treatment was terminated, and the solid content was dried with a vacuum dryer for 12 hours to obtain toner particles having a volume average particle diameter of 7 μm.

  Toner (nonmagnetic one-component developer) was obtained by mixing 100 parts of toner particles and 2 parts of NA50Y (fumed silica treated with silicone oil and aminosilane) by Nippon Aerosil Co., Ltd. using a Henschel mixer.

<Examples C2 to C5>
In Example C2, 1-chloropentane is 26 parts, in Example C3 1-chloropentane is 31 parts, in Example C4 1-chloropentane is 45 parts, in Example C5 1-chloropentane is 49 parts. In addition, a toner was obtained in the same manner as in Example C1, except that each was changed.

<Examples C6 to C8>
In Example C6, a toner was obtained in the same manner as in Example C1, except that 1-chloropentane was 38 parts and pentylated polyethyleneimine was 0.024 parts with respect to 100 parts of toner base particles.
In Example C7, a toner was obtained in the same manner as in Example C1, except that 1-chloropentane was 39 parts and pentylated polyethyleneimine was 0.15 parts with respect to 100 parts of toner base particles.
In Example C8, a toner was obtained in the same manner as in Example C1 except that 38 parts of 1-chloropentane was used and toner base particles (2) were used instead of toner base particles (1).

<Example C9>
A toner was obtained in the same manner as in Example C1, except that pentylated polyethyleneimine was replaced with ethylated polypropyleneimine. The ethylated polypropyleneimine used here was prepared by reacting 100 parts of polypropyleneimine with 22 parts of chloroethane. The residual ratio of imino groups was 37%.

<Comparative Example C1>
A toner was obtained in the same manner as in Example C1, except that the polyethyleneimine used in the preparation of the pentylated polyethyleneimine in Example C1 was used without being alkylated.

<Comparative Example C2>
A toner was obtained in the same manner as in Example C1, except that the polypropylene imine used in the preparation of the ethylated polypropylene imine in Example C9 was used without being alkylated.

<Evaluation>
The developer of each example and comparative example was loaded into DocuPrint P300d manufactured by Fuji Xerox. Using C2 paper manufactured by Fuji Xerox Co., Ltd., 30000 halftone images with a toner loading of 1 g / cm ³ were output in a 28 ° C./85% RH environment. The 30000th image was observed with the naked eye and evaluated according to the following criteria. The results are shown in Tables 1 to 3.
-Criteria-
A: There is sufficient density over the entire surface, and there is no density unevenness.
B +: Intermediate between A and B B: A portion with a low density is partly present and density unevenness is observed, but it is minor and causes no problem.
C: The density is low over the entire surface.

1Y, 1M, 1C, 1K, photoconductor (an example of an image carrier)
2Y, 2M, 2C, 2K, charging roll (an example of charging means)
3. Exposure device (an example of electrostatic charge image forming means)
3Y, 3M, 3C, 3K Laser beams 4Y, 4M, 4C, 4K Developing device (an example of developing means)
5Y, 5M, 5C, 5K primary transfer roll (an example of primary transfer means)
6Y, 6M, 6C, 6K Photoconductor cleaning device (an example of cleaning means)
8Y, 8M, 8C, 8K Toner cartridge 10Y, 10M, 10C, 10K Image forming unit 20 Intermediate transfer belt (an example of an intermediate transfer member)
22 Drive roll 24 Support roll 26 Secondary transfer roll (an example of secondary transfer means)
28 Fixing device (an example of fixing means)
30 Intermediate transfer member cleaning device P Recording paper (an example of a recording medium)

107 photoconductor (an example of an image carrier)
108 Charging roll (an example of charging means)
109 Exposure apparatus (an example of electrostatic charge image forming means)
111 Developing device (an example of developing means)
112 Transfer device (an example of transfer means)
113 photoconductor cleaning device (an example of cleaning means)
115 Fixing device (an example of fixing means)
116 Mounting rail 117 Housing 118 Opening 200 for exposure Process cartridge 300 Recording paper (an example of a recording medium)

Claims (11)

Toner particles containing a binder resin and having at least one compound selected from alkylated polyalkylene biguanides, alkylated polyalkylene guanidines, and alkylated polyalkylene imines on the surface;
A toner for developing an electrostatic charge image.   The electrostatic charge image developing toner according to claim 1, wherein the compound has a remaining ratio of imino groups in the molecule of 20% or more and 50% or less.   3. The electrostatic image developing toner according to claim 1, wherein the toner particles have the compound in a range of 0.0001 g or more and 0.0010 g or less per 1 g of toner particles on the surface thereof.   4. The electrostatic image developing toner according to claim 1, wherein the toner particles have at least an alkylated polyhexamethylene biguanide on the surface as the compound. 5.   4. The electrostatic image developing toner according to claim 1, wherein the toner particles have at least alkylated polyhexamethylene guanidine on the surface as the compound. 5.   4. The electrostatic image developing toner according to claim 1, wherein the toner particles have at least an alkylated polyethyleneimine on the surface as the compound. 5.   An electrostatic charge image developer comprising the electrostatic charge image developing toner according to claim 1. Containing the toner for developing an electrostatic charge image according to any one of claims 1 to 6,
A toner cartridge to be attached to and detached from the image forming apparatus. A developing means for containing the electrostatic charge image developer according to claim 7 and developing the electrostatic charge image formed on the surface of the image carrier as a toner image by the electrostatic charge image developer,
A process cartridge attached to and detached from the image forming apparatus. An image carrier,
Charging means for charging the surface of the image carrier;
An electrostatic charge image forming means for forming an electrostatic charge image on the surface of the charged image carrier;
Development means for containing the electrostatic image developer according to claim 7 and developing the electrostatic image formed on the surface of the image carrier as a toner image by the electrostatic image developer;
Transfer means for transferring a toner image formed on the surface of the image carrier to the surface of a recording medium;
Fixing means for fixing the toner image transferred to the surface of the recording medium;
An image forming apparatus comprising: A charging step for charging the surface of the image carrier;
An electrostatic charge image forming step of forming an electrostatic charge image on the surface of the charged image carrier;
A developing step of developing an electrostatic charge image formed on the surface of the image carrier as a toner image with the electrostatic charge image developer according to claim 7;
A transfer step of transferring a toner image formed on the surface of the image carrier to the surface of a recording medium;
A fixing step of fixing the toner image transferred to the surface of the recording medium;
An image forming method comprising: