JP2015102738A - Positively charged dry toner, developer, developer cartridge, process cartridge, image forming apparatus, and image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide positively charged dry toner with excellent positive chargeability.SOLUTION: Positively charged dry toner includes a binder resin and a colorant. Toner particle surface is modified by polyallylamines.

Description

  The present invention relates to a positively charged dry toner, a 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.

  As a dry toner for positive charging, for example, Patent Document 1 discloses a powder containing metal chelated binder resin (A), a colorant (B), and a charge control agent (C) as essential components. A positively charged toner for developing an electrostatic image, wherein the fluidity imparting agent (D) powder is a readily chargeable silica surface-treated with a silane coupling agent having an amino group. Is described.

  Patent Document 2 describes a positively charged black toner obtained by modifying the surface of toner base particles containing carbon black as a colorant and a binder resin with polyalkyleneimine.

  On the other hand, Patent Document 3 describes a toner for photofixing in which a salt such as hydrochloride of a polyallylamine compound is mixed when a binder resin and a colorant are kneaded.

Japanese Patent Laid-Open No. 08-262788 Japanese Patent No. 5115379 Japanese Patent No. 4961963

  An object of the present invention is to provide a positively chargeable dry toner excellent in positive chargeability, a developer, a developer cartridge containing the developer, a process cartridge, an image forming apparatus, and an image forming method.

  The invention according to claim 1 is a positively chargeable dry toner comprising at least a binder resin and a colorant, wherein the surface of the toner particles is surface-modified with polyallylamines.

（１）
（式（１）において、ｍは、２以上５００以下の整数である。）

（２）
（式（２）において、Ｒ^１およびＲ^２は、それぞれ独立して水素原子または炭素数１以上２０以下の脂肪族炭化水素基を示し、ｍ，ｎは、それぞれ独立して１以上２０以下の整数である。ｌは、２以上２０以下の整数である。）

（３）
（式（３）において、ｍ，ｎは、それぞれ独立して１以上１００以下の整数である。ｌは、２以上２００以下の整数である。）

（４）
（式（４）において、ｍ，ｎは、それぞれ独立して１以上１００以下の整数である。ｌは、２以上２００以下の整数である。） According to a second aspect of the present invention, the polyallylamine is a polyallylamine represented by the following formula (1), a polyallylamine represented by the formula (2), a polyallylamine represented by the formula (3), and the formula (4). The positively charged dry toner according to claim 1, which is at least one of the polyallylamines shown.

(1)
(In Formula (1), m is an integer of 2 or more and 500 or less.)

(2)
(In Formula (2), R ¹ and R ² each independently represent a hydrogen atom or an aliphatic hydrocarbon group having 1 to 20 carbon atoms, and m and n are each independently 1 to 20) (It is an integer. L is an integer of 2 to 20.)

(3)
(In Formula (3), m and n are each independently an integer of 1 to 100. l is an integer of 2 to 200.)

(4)
(In Formula (4), m and n are each independently an integer of 1 to 100. l is an integer of 2 to 200.)

  The invention according to claim 3 is the positively chargeable dry toner according to claim 1 or 2, wherein the polyallylamines have a weight average molecular weight in the range of 1,000 to 25,000.

  According to a fourth aspect of the present invention, there is provided a developer comprising the positively charged dry toner according to any one of the first to third aspects.

  The invention according to claim 5 is a developer cartridge in which the developer according to claim 4 is accommodated.

  The invention according to claim 6 is a process cartridge in which the developer according to claim 4 is accommodated.

  According to a seventh aspect of the present invention, there is provided the image holding member according to the fourth aspect, the latent image forming means for 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. An image forming apparatus comprising: a developing unit that forms a toner image by developing with the developer described above; and a transfer unit that transfers the toner image formed on the surface of the image holding member to a transfer target.

  According to an eighth aspect of the present invention, the latent image forming step of forming a latent image on the surface of the image carrier and the latent image formed on the surface of the image carrier are developed with the developer according to the fourth aspect. Then, the image forming method includes a developing step for forming a toner image and a transfer step for transferring the toner image formed on the surface of the image holding member to a transfer target.

  According to the first aspect of the present invention, there is provided a positively chargeable dry toner excellent in positive chargeability as compared with the case where the toner particle surface is not surface-modified with polyallylamines.

  According to the invention of claim 2, the polyallylamines include the polyallylamine represented by the above formula (1), the polyallylamine represented by the formula (2), the polyallylamine represented by the formula (3), and the formula (4). Compared to the case where at least one of the polyallylamines represented by the formula (1) is not present, a positively charged dry toner excellent in positive chargeability is provided.

  According to the invention of claim 3, there is provided a positively chargeable dry toner excellent in positive chargeability as compared with the case where the weight average molecular weight of the polyallylamine is not in the range of not less than 1,000 and not more than 25,000. The

  According to the fourth aspect of the present invention, there is provided a developer excellent in positive chargeability as compared with the case where the toner particle surface is not surface-modified with polyallylamines.

  According to the fifth aspect of the present invention, there is provided a developer cartridge that contains a developer that is excellent in positive chargeability as compared with the case where the surface of the toner particles is not surface-modified with polyallylamines.

  According to the sixth aspect of the present invention, there is provided a process cartridge in which a developer having a positive chargeability is contained as compared with a case where the surface of the toner particles is not surface-modified with polyallylamines.

  According to the seventh aspect of the present invention, there is provided an image forming apparatus using a developer that is excellent in positive chargeability as compared with the case where the surface of toner particles is not surface-modified with polyallylamines.

  According to the eighth aspect of the present invention, there is provided an image forming method using a developer that is excellent in positive chargeability as compared with the case where the surface of toner particles is not surface-modified with polyallylamines.

It is a schematic structure figure showing an example of a process cartridge concerning an embodiment of the present invention. 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.

<Positive charge dry toner>
The positively chargeable dry toner according to the embodiment of the present invention includes at least a binder resin and a colorant, and the toner particle surface is surface-modified with polyallylamines. The positively charged dry toner may contain other components such as a release agent, if necessary.

  Common binder resins used in dry toners are polyester resins and styrene / acrylic resins, but polyester resins with particularly good fixability and color developability tend to be negatively charged. Commercially available charge control agents for positive charging include nigrosine dyes such as “Bontron N-01”, “Bontron N-04”, “Bontron N-07” (manufactured by Orient Chemical Industries), “ CHUO CCA-3 "(manufactured by Chuo Gosei Co., Ltd.), etc .; triphenylmethane dyes containing tertiary amines as side chains; quaternary ammonium salt compounds such as" Bontron P-51 "(manufactured by Orient Chemical Industries)," TP-415 "(manufactured by Hodogaya Chemical Co., Ltd.), cetyltrimethylammonium bromide," COPYCHARGEPXVP435 "(manufactured by Hoechst), and the like. The charge control agent applicable to color is only a colorless quaternary ammonium salt compound. Yes, the others are colored and can only be applied to black. Thus, there are very few types of charge control agents for positive charging, and the effect is also limited. In particular, since carbon black tends to be negatively charged, a black toner containing carbon black as a colorant is difficult to obtain sufficient positive chargeability. Conventionally, since the charge control agent is externally added to the toner or added at the time of melt kneading, the charge control agent is often detached from the surface of the toner particles or embedded in the toner particles. It was not easy to control the arrangement of the charge control agent. If the charge control agent is detached from the surface of the toner particles or embedded in the toner particles, the charge stability will be lost, especially when new toner is replenished while the toner stays in the developing unit for a long time. Such image defects are likely to occur.

  The positively chargeable dry toner according to this embodiment is excellent in positive chargeability because the surface of the toner particles is surface-modified with polyallylamines. In the positively chargeable dry toner according to this embodiment, it is considered that alkaline polyallylamine is chemically adsorbed on the surface of acidic toner particles by an acid-base reaction. Since polyallylamines having good positive chargeability are strongly chemically adsorbed on the surface of the toner particles, the possibility of desorption is extremely low, and stable positive chargeability is considered to be obtained. Further, it is considered that the polyallylamines are almost uniformly coated on the toner particle surface, so that the toner particles are hardly affected by the charge of the binder resin and the colorant. That is, the effects of this embodiment cannot be obtained by simply mixing polyallylamines and resin, or by adding polyallylamines when developing into a developer. The desired positive chargeability can be obtained only after the step of chemically adsorbing allylamines.

  Polyallylamines are highly cationic substances, and if this material is present on the surface of the toner particles, it is considered that the positively charged nitrogen group functions as a charge control agent, so that the toner particles are likely to be positively charged. .

  Examples of polyallylamines include polyallylamine represented by the following formula (1), polyallylamine represented by formula (2), polyallylamine represented by formula (3), polyallylamine represented by formula (4), and the like. .

（１）
（式（１）において、ｍは、２以上５００以下の整数であり、２５以上４５０以下の整数が好ましい。）

(1)
(In Formula (1), m is an integer of 2 or more and 500 or less, and an integer of 25 or more and 450 or less is preferable.)

（２）
（式（２）において、Ｒ^１およびＲ^２は、それぞれ独立して水素原子または炭素数１以上２０以下の脂肪族炭化水素基を示し、ｍ，ｎは、それぞれ独立して１以上２０以下の整数であり、１以上１０以下の整数が好ましい。ｌは、２以上２０以下の整数であり、２以上１０以下の整数が好ましい。）

(2)
(In Formula (2), R ¹ and R ² each independently represent a hydrogen atom or an aliphatic hydrocarbon group having 1 to 20 carbon atoms, and m and n are each independently 1 to 20) And is an integer, preferably an integer of 1 to 10. l is an integer of 2 to 20, preferably an integer of 2 to 10.)

R ¹ and R ² are a hydrogen atom or an aliphatic hydrocarbon group having 1 to 20 carbon atoms, preferably an aliphatic hydrocarbon group having 1 to 20 carbon atoms. Examples of the aliphatic hydrocarbon group having 1 to 20 carbon atoms include a methyl group, an ethyl group, a linear or branched propyl group, a butyl group, a pentyl group, a hexyl group, and an octyl group, and a methyl group is preferable.

（３）
（式（３）において、ｍ，ｎは、それぞれ独立して１以上１００以下の整数であり、１以上５０以下の整数が好ましい。ｌは、２以上２００以下の整数であり、２以上１００以下の整数が好ましい。）

(3)
(In Formula (3), m and n are each independently an integer of 1 to 100, preferably an integer of 1 to 50. l is an integer of 2 to 200, and 2 to 100. Is preferred.)

（４）
（式（４）において、ｍ，ｎは、それぞれ独立して１以上１００以下の整数であり、１以上５０以下の整数が好ましい。ｌは、２以上２００以下の整数であり、２以上１００以下の整数が好ましい。）

(4)
(In Formula (4), m and n are each independently an integer of 1 to 100, preferably an integer of 1 to 50. l is an integer of 2 to 200, and 2 to 100. Is preferred.)

  The amount of polyallylamines with respect to the toner particles is, for example, preferably in the range of 0.1 to 3 parts by weight with respect to 100 parts by weight of the toner particles, and 0.2 to 2 parts by weight. A range is more preferable. When the amount of polyallylamines relative to the toner particles is less than 0.1 parts by mass with respect to 100 parts by mass of the toner particles, the positive chargeability may be inferior. When the amount exceeds 3 parts by mass, charging is performed in a high temperature and high humidity environment. In some cases, the charge amount becomes excessive in a low temperature and low humidity environment.

  The weight average molecular weight of the polyallylamines is preferably in the range of 1,000 to 25,000, and more preferably in the range of 3,000 to 15,000. If the weight average molecular weight of the polyallylamine is less than 1,000, the positive chargeability may be weak and the target developability may not be obtained. If the weight average molecular weight exceeds 25,000, the positive chargeability is too strong. Sexuality may worsen. Further, when the weight average molecular weight of the polyallylamine exceeds 25,000, the transferability of the toner may be deteriorated. Therefore, by setting the weight average molecular weight of the polyallylamine within the above range, a toner having more excellent positive chargeability can be obtained more effectively.

  The polyallylamine is preferably alkaline. If the polyallylamine is alkaline, an acid-base reaction is liable to occur with the acidic toner particle surface, and chemical adsorption is considered to occur. On the contrary, if the polyallylamine is an acidic type such as hydrochloride, the surface of the toner particles is also acidic, so there is almost no acid-base reaction and the polyallylamines on the toner particle surface. Is not likely to be chemisorbed. Furthermore, since polyallylamines are almost colorless and transparent, they may be applied to color toners.

  Examples of polyallylamines include commercially available PAA-01, PAA-03, PAA-05, PAA-08, PAA-15, PAA-15C, PAA-25, PAA-1112, PAA-N5000, PAA- And U5000 (manufactured by Nitto Bo Medical Co., Ltd.).

(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 65% by mass to 95% by mass with respect to the entire toner particles.

  The acid value of the binder resin is preferably in the range of 1 mgKOH / g to 30 mgKOH / g, and more preferably in the range of 7 mgKOH / g to 20 mgKOH / g. If the acid value of the binder resin is less than 1 mgKOH / g, the amount of particles adsorbed on the polyallylamines used as the surface modifier may be reduced, so that a desired positive charge amount may not be obtained or phase inversion may occur. When granulating using emulsification, the granulating property may be deteriorated. If the acid value of the binder resin exceeds 30 mgKOH / g, the positive chargeability may be inhibited even if polyallylamines are adsorbed on the particle surface.

(Other ingredients)
The toner particles according to the exemplary embodiment may contain a colorant and, if necessary, other additives such as a release agent, a charge control agent, silica powder, and a metal oxide. 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 20% 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 0.1% by mass to 15% 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 exemplary embodiment is not particularly limited, and examples thereof include a wet production method such as a kneading and pulverizing method, a liquid emulsification method, and a polymerization method.

  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.

(Surface modification method)
The surface-modified toner particles according to the present embodiment are produced by, for example, a method including a step of forming a polyallylamine layer covering the toner particle surface by surface-modifying the toner particles with polyallylamines. Since polyallylamines are water-soluble polymers, in the wet manufacturing method in which the granules are granulated in a liquid, the polyallylamines may be adsorbed on the toner particle surfaces as they are after washing with water before the drying step.

Specifically, the surface modification of the toner particles is produced, for example, by the following method.
(1) Add acid (about 1N hydrochloric acid or nitric acid) to the slurry containing toner particles and water and adjust the pH to about 3 to 5 to return the acid sites on the toner particle surface back to the acid as reliably as possible (2) Ion exchange Perform solid-liquid separation by washing with water or by centrifugation, etc., and remove excess acid (3) After reslurry, add water-soluble polyallylamines, for example, a liquid temperature range of 20 ° C. to 35 ° C. (4) Washing with ion-exchanged water or the like, or performing solid-liquid separation by centrifugation or the like to remove excess polyamines (for example, conductivity is about 20 μS / cm or less) Until)
(5) After filtration, dry (for example, about 35 ° C., at least about 24 hours, moisture content of 1% or less) and crush.

When a polyester resin having an acid value of about 10 is used as a binder resin for toner particles and granulation is performed using phase inversion emulsification, the filtrate on the surface of the toner particles becomes alkaline because the filtrate after washing is alkaline. It seems that there are many parts where the sites (for example, —COOH group) are neutralized to have a salt structure (for example, —COO ^— Na ⁺ , —COO ^— NH ₄ ⁺ ). Therefore, it is preferable to return the salt structure on the toner particle surface to an acid (for example, —COOH group) by performing the step (1) so that polyallylamines are more easily adsorbed by an acid-base reaction. However, the steps (1) and (2) are not essential and may be omitted when a desired positive charge amount is obtained.

<Average particle size of positively charged dry toner>
The volume average particle size of the positively chargeable dry toner according to this embodiment is preferably in the range of 4 μm to 8 μm, more preferably in the range of 5 μm to 7 μm, and the number average particle size is in the range of 3 μm to 7 μm. The range of 4 μm or more and 6 μm or less is more preferable.

  The volume average particle size and the number average particle size are measured by measuring with a Coulter Multisizer II type (manufactured by Beckman-Coulter) with an aperture diameter of 50 μm. At this time, the measurement is performed after the toner is dispersed in an electrolyte aqueous solution (isoton aqueous solution) and dispersed by ultrasonic waves for 30 seconds.

<Developer>
In the present embodiment, the developer is not particularly limited except that it contains the positively chargeable dry toner according to the present embodiment, and may have an appropriate component composition depending on the purpose. The developer in this embodiment becomes a one-component developer when a positively charged dry toner is used alone, and becomes a two-component developer when used in combination with a carrier.

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

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

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

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

  The mixing ratio of the positively chargeable dry toner of the present embodiment and the carrier in the developer is not particularly limited and may be appropriately selected according to the purpose.

<Toner cartridge>
The toner cartridge according to the present embodiment is not particularly limited as long as it contains the positive charging dry toner according to the present embodiment. For example, the toner cartridge is attached to and detached from an image forming apparatus including a developing unit, and stores the positively charged dry toner according to the present embodiment as toner to be supplied to the developing unit.

<Developer cartridge>
The developer cartridge according to the present embodiment is not particularly limited as long as it contains a developer including the positively charged dry toner according to the present embodiment. For example, the developer cartridge is attached to and detached from an image forming apparatus including a developing unit, and the developer including the positively charged dry toner according to the present embodiment is accommodated as a developer to be supplied to the developing unit. It is what.

<Process cartridge>
The process cartridge according to the present embodiment is not particularly limited as long as it contains the developer including the positively charged dry toner according to the present embodiment. The process cartridge includes, for example, a developing unit that develops a latent image formed on the surface of the image carrier using a developer to form a toner image. The process cartridge according to the present embodiment includes, as necessary, an image carrier, a charging unit that charges the surface of the image carrier, a latent image forming unit that forms a latent image on the surface of the charged image carrier, and an image. A transfer unit that transfers a toner image formed on the surface of the holding member to the transfer target, an image holding member cleaning unit that removes residual toner remaining on the surface of the image holding member after transfer, and a transfer target; There may be provided at least one selected from the group consisting of fixing means for fixing the toner image transferred to the body.

  A schematic configuration of an example of a process cartridge according to an embodiment of the present invention is shown in FIG. 1, and the configuration will be described. The process cartridge 1 includes a photoconductor (electrophotographic photoconductor) 14 as an image carrier on which an electrostatic latent image is formed, a charging device 10 as a charging unit that charges the surface of the photoconductor 14, and a photoconductor 14. A developing device 16 as a developing means for forming a toner image by attaching toner to the electrostatic latent image formed on the surface, and the surface of the photoconductor 14 are contacted, and the residual remaining on the surface of the photoconductor 14 after transfer A cleaning blade 20 as an image carrier cleaning means that removes toner and cleans it is integrally supported, and is detachable from the image forming apparatus. When mounted on the image forming apparatus, an exposure device 12 as a latent image forming means for forming an electrostatic latent image on the surface of the photosensitive member 14 around the photosensitive member 14 by the charging device 10, laser light or reflected light of the document. The developing device 16, the transfer roll 18 serving as transfer means for transferring the toner image on the surface of the photoreceptor 14 to the recording paper 24 as a transfer target, and the cleaning blade 20 are arranged in this order. In FIG. 1, description of functional units normally required in other electrophotographic processes is omitted.

  The operation of the process cartridge 1 according to this embodiment will be described.

  First, the surface of the photoreceptor 14 is charged by the charging device 10 (charging process). Next, light is applied to the surface of the photoconductor 14 by the exposure device 12, and the charged charges in the exposed portion are removed, and an electrostatic latent image (electrostatic charge image) is formed according to the image information ( Latent image forming step). Thereafter, the electrostatic latent image is developed by the developing device 16, and a toner image is formed on the surface of the photoreceptor 14 (developing step). For example, in the case of a digital electrophotographic copying machine using an organic photosensitive member as the photosensitive member 14 and using a laser beam as the exposure device 12, the surface of the photosensitive member 14 is given a negative charge by the charging device 10, and the laser beam A digital latent image is formed in the form of dots by light, and toner is applied to the portion irradiated with the laser beam by the developing device 16 to be visualized. In this case, a negative bias is applied to the developing device 16. Next, a recording sheet 24 as a transfer object is superimposed on the toner image by the transfer roll 18, and the charge opposite in polarity to the toner is given to the recording sheet 24 from the back side of the recording sheet 24, and the toner image is formed by electrostatic force. It is transferred onto the recording paper 24 (transfer process). The transferred toner image is subjected to heat and pressure in a fixing device having a fixing roll 22 as fixing means, and is fused and fixed to the recording paper 24 (fixing step). On the other hand, the residual toner such as toner remaining on the surface of the photoconductor 14 without being transferred is removed by the cleaning blade 20 (image carrier cleaning step). One cycle is completed in a series of processes from the charging step to the image carrier cleaning step. In FIG. 1, the toner image is directly transferred to the recording paper 24 by the transfer roll 18, but may be transferred via an intermediate transfer member such as an intermediate transfer belt.

  As the charging device 10 that is a charging means, for example, a charger such as a corotron as shown in FIG. 1 is used, but a conductive or semiconductive charging roll may be used. A contact charger using a conductive or semiconductive charging roll may apply a direct current to the photoreceptor 14 or may apply an alternating current superimposed thereon. For example, the charging device 10 charges the surface of the photoconductor 14 by generating a discharge in a minute space near the contact portion with the photoconductor 14. Normally, it is charged to −300V or more and −1000V or less. The conductive or semiconductive charging roll may have a single layer structure or a multiple structure. Further, a mechanism for cleaning the surface of the charging roll may be provided.

  The photoreceptor 14 has a function of forming at least an electrostatic latent image (electrostatic charge image). In the electrophotographic photosensitive member, an undercoat layer, a charge generation layer containing a charge generation material, and a charge transport layer containing a charge transport material are formed in this order on the outer peripheral surface of a cylindrical conductive substrate as necessary. It is a thing. The order of stacking the charge generation layer and the charge transport layer may be reversed. These are laminated photoconductors in which a charge generation material and a charge transport material are contained in separate layers (charge generation layer, charge transport layer), but both the charge generation material and the charge transport material are the same. A single-layer type photoreceptor included in the above layer may be used, and a laminated photoreceptor is preferable. Further, an intermediate layer may be provided between the undercoat layer and the photosensitive layer. Further, a protective layer may be provided on the photosensitive layer. In addition, other types of photosensitive layers such as an amorphous silicon photosensitive film may be used in addition to the organic photoreceptor.

  The exposure apparatus 12 is not particularly limited. For example, a laser optical system that exposes a light source such as semiconductor laser light, LED (Light Emitting Diode) light, and liquid crystal shutter light on the surface of the photoconductor 14 in a desired image manner, Examples include optical system devices such as LED arrays.

  The developing unit has a function of developing the electrostatic latent image formed on the photoreceptor 14 with a one-component developer or a two-component developer containing an electrostatic charge image developing toner to form a toner image. Such a developing device is not particularly limited as long as it has the above-described functions, and may be appropriately selected depending on the purpose. Even a system in which the toner layer is in contact with the photoconductor 14 is not in contact with the system. It may be a thing. For example, as shown in FIG. 1, a developing device having a function of attaching toner for developing an electrostatic image to the photosensitive member 14 using the developing device 16, or developing having a function of attaching the toner to the photosensitive member 14 using a brush or the like. And a known developing device.

  As a transfer device as a transfer means, for example, a charge opposite in polarity to the toner is applied to the recording paper 24 from the back side of the recording paper 24, and the toner image is transferred to the recording paper 24 by electrostatic force, or as shown in FIG. A transfer roll and a transfer roll pressing device using a conductive or semiconductive roll or the like that directly transfers to the surface of the recording paper 24 via the recording paper 24 may be used. A direct current may be applied to the transfer roll as a transfer current applied to the image carrier, or an alternating current may be applied in a superimposed manner. The transfer roll may be arbitrarily set according to the width of the image area to be charged, the shape of the transfer charger, the opening width, the process speed (circumferential speed), and the like. Further, a single layer foam roll or the like is suitably used as a transfer roll for cost reduction. The transfer method may be a method of transferring directly to the recording paper 24 or a method of transferring to the recording paper 24 via an intermediate transfer member.

  A known intermediate transfer member may be used as the intermediate transfer member. Materials used for the intermediate transfer member include polycarbonate resin (PC), polyvinylidene fluoride (PVDF), polyalkylene phthalate, PC / polyalkylene terephthalate (PAT) blend material, ethylene tetrafluoroethylene copolymer (ETFE) / PC, ETFE / PAT, PC / PAT blend materials, and the like can be mentioned. From the viewpoint of mechanical strength, an intermediate transfer belt using a thermosetting polyimide resin is preferable.

  The image carrier cleaning means may be selected as appropriate as long as it removes residual toner on the image carrier and cleans it, and employs a blade cleaning method, a brush cleaning method, a roll cleaning method, or the like. . Among these, it is preferable to use a cleaning blade. Examples of the material for the cleaning blade include urethane rubber, neoprene rubber, and silicone rubber. Among them, it is particularly preferable to use a polyurethane elastic body because of its excellent wear resistance.

  The fixing device as the fixing unit is not particularly limited as long as the toner image transferred onto the recording paper 24 is fixed by heating, pressing, or heating and pressing. For example, a fixing device including a heating roll and a pressure roll is used.

  Examples of the recording paper 24 that is a transfer target to which the toner image is transferred include plain paper, an OHP sheet, and the like used in electrophotographic copying machines and printers. In order to further improve the smoothness of the image surface after fixing, it is preferable that the surface of the transfer material is as smooth as possible. For example, coated paper in which the surface of plain paper is coated with resin, art paper for printing, etc. Preferably used.

<Image forming apparatus and image forming method>
The image forming apparatus according to the present embodiment is not particularly limited as long as it contains the developer for developing an electrostatic charge image including the toner for developing an electrostatic charge image according to the present embodiment. The image forming apparatus includes, for example, an image carrier, a charging unit that charges the surface of the image carrier, a latent image forming unit that forms a latent image on the surface of the image carrier, and a surface of the image carrier. The image forming apparatus includes a developing unit that develops the latent image using a developer to form a toner image, and a transfer unit that transfers the developed toner image to a transfer target. The image forming apparatus according to the present exemplary embodiment removes residual toner and the like remaining on the surface of the image holding member after transfer, and a fixing unit for fixing the toner image transferred to the transfer target, as necessary. And at least one selected from the group consisting of an image carrier cleaning means for cleaning. The image forming apparatus according to the present embodiment may use the process cartridge.

  FIG. 2 shows a schematic configuration of an example of the image forming apparatus according to the present embodiment, and the configuration will be described. The image forming apparatus 3 includes a photosensitive member 14 as an image carrier on which an electrostatic latent image is formed, a charging device 10 as a charging unit that charges the surface of the photosensitive member 14, and laser light or reflected light of a document. An exposure device 12 as a latent image forming unit that forms an electrostatic latent image on the surface of the photoconductor 14 and a developing unit that forms a toner image by attaching toner to the electrostatic latent image formed on the surface of the photoconductor 14. A developing device 16, a transfer roll 18 as a transfer means for transferring the toner image on the surface of the photoconductor 14 to a recording paper 24 as a transfer target, and the surface of the photoconductor 14, and the photoconductor after transfer. And a cleaning blade 20 as an image carrier cleaning means for removing residual toner and the like remaining on the surface of the image 14 for cleaning. In the image forming apparatus 3, a charging device 10, an exposure device 12, a developing device 16, a transfer roll 18, and a cleaning blade 20 are arranged around the photoconductor 14 in this order. In addition, a fixing device having a fixing roll 22 is provided as fixing means. In FIG. 2, functional units normally required in other electrophotographic processes are omitted. Each configuration of the image forming apparatus 3 and the operation during image formation are the same as those of the process cartridge 1 of FIG.

  The configurations of the process cartridge and the image forming apparatus according to the present embodiment are not limited to these, and conventionally known configurations may be applied as the configurations of the electrophotographic process cartridge and the image forming apparatus. That is, conventionally known image holding members, charging means, latent image forming means, developing means, transfer means, image holding member cleaning means, charge eliminating means, paper feeding means, conveying means, image control means, and the like as required. Is appropriately adopted. These configurations are not particularly limited in the present embodiment.

  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]
The toner of this embodiment is obtained by the following method. That is, the following resin particle dispersion, colorant dispersion, and release agent dispersion were prepared. Next, while a predetermined amount of these were mixed and stirred, a polymer of an inorganic metal salt was added thereto and ionically neutralized to form aggregates of the above particles to obtain a desired toner particle size. Next, the pH of the system was adjusted from a weakly acidic to a neutral range with an inorganic hydroxide, and then heated to the glass transition temperature or higher of the resin particles for coalescence. After completion of the reaction, desired toner particles were obtained through sufficient washing, solid-liquid separation, and drying processes.

(Synthesis of crystalline polyester resin)
In a flask, 1982 parts by mass of sebacic acid, 1490 parts by mass of ethylene glycol, 59.2 parts by mass of sodium dimethyl 5-sulfonate and 0.8 part by mass of dibutyltin oxide were reacted at 180 ° C. for 5 hours in a nitrogen atmosphere. Subsequently, a condensation reaction was performed at 220 ° C. under reduced pressure. The polymer was sampled in the middle, and when the molecular weight reached Mw (weight average molecular weight) = 20,000 and Mn (number average molecular weight) = 8,500 by gel permeation chromatography (GPC), the reaction was stopped, and the crystallinity A polyester resin was obtained. The dissolution temperature (DSC peak temperature) was 71 ° C. The measurement result of the content of sodium dimethyl 5-phthalate by NMR was 1 mol% (vs. all components).

(Crystalline polyester resin particle dispersion)
Prepare 160 parts by weight of crystalline polyester resin, 233 parts by weight of ethyl acetate, and 0.1 parts by weight of aqueous sodium hydroxide (0.3N), put them in a separable flask and heat at 75 ° C. A resin mixture was prepared by stirring with a motor (manufactured by Shinto Kagaku Co., Ltd.). While further stirring this resin mixture, 373 parts by mass of ion-exchanged water is gradually added, phase inversion emulsification is performed, the temperature is lowered to 40 ° C. at a temperature lowering rate of 10 ° C./min, and the solvent is removed to remove the crystalline polyester resin. A particle dispersion (solid content concentration: 30% by mass) was obtained.

(Synthesis of non-crystalline polyester resin)
In a heat-dried two-necked flask, 200 parts by mass of dimethyl terephthalate, 85 parts by mass of 1,3-butanediol, and 0.3 parts by mass of dibutyltin oxide as a catalyst were added, and the air in the container was reduced by a vacuum operation. Was made into an inert atmosphere with nitrogen gas, and it stirred by mechanical stirring at 180 rpm for 5 hours. Thereafter, the temperature was gradually raised to 230 ° C. under reduced pressure, and the mixture was stirred for 2 hours. When it became viscous, it was air-cooled, the reaction was stopped, and the amorphous polyester resin (the aromatic dicarboxylic acid-derived component) 240 parts by mass of an amorphous polyester resin containing an acid-derived constituent component having a content of 100 constituent mol% and an alcohol-derived constituent component having an aliphatic diol-derived constituent component content of 100 constituent mol%. did.

  As a result of molecular weight measurement (polystyrene conversion) by GPC, the resulting amorphous polyester resin (1) had a weight average molecular weight (Mw) of 9,500 and a number average molecular weight (Mn) of 4,200. Further, when the DSC spectrum of the non-crystalline polyester resin (1) was measured using the above-mentioned differential scanning calorimeter (DSC), no clear peak was shown, and a stepwise endothermic change was observed. The glass transition temperature at the midpoint of the stepwise endothermic change was 55 ° C. The resin acid value was 18 mgKOH / g.

(Non-crystalline polyester resin particle dispersion)
Prepare 160 parts by mass of an amorphous polyester resin (1), 233 parts by mass of ethyl acetate, and 0.1 parts by mass of an aqueous sodium hydroxide solution (0.3N). Put these in a separable flask at 70 ° C. The mixture was heated and stirred with a three-one motor (Shinto Kagaku Co., Ltd.) to prepare a resin mixture. While further stirring this resin mixture, 373 parts by mass of ion-exchanged water is gradually added, phase inversion emulsification is performed, and the temperature is lowered to 40 ° C. at a temperature lowering rate of 1 ° C./min. A particle dispersion (solid content concentration: 30% by mass) was obtained.

(Preparation of colorant dispersion)
Cyan pigment (CI Pigment Blue 15: 3, manufactured by Dainichi Seika) 45 parts by mass Ionic surfactant (Neogen RK, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 5 parts by mass Ion-exchanged water 200 parts by mass And a homogenizer (IKA Ultra Tarrax) for 10 minutes to obtain a colorant dispersion having a volume average particle size of 170 nm.

  Further, in the same manner as the method for preparing a cyan pigment dispersion, yellow pigment (CI Pigment Yellow 74, manufactured by Dainichi Seika), magenta pigment (CI Pigment Red 269, manufactured by Dainichi Seika), black pigment (CI Pigment Black 7, manufactured by Mitsubishi Chemical Corporation) was used to obtain a colorant dispersion.

(Preparation of release agent dispersion)
Alkyl wax FNP0085 (melting temperature 86 ° C, manufactured by Nippon Seiwa Co., Ltd.) 45 parts by weight Cationic surfactant (Neogen RK, manufactured by Daiichi Kogyo Seiyaku) 5 parts by weight Ion-exchanged water 200 parts by weight The above is heated to 90 ° C. After sufficiently dispersing with IKA Ultra Turrax T50, it was dispersed with a pressure discharge type gorin homogenizer to obtain a release agent dispersion having a volume average particle size of 200 nm and a solid content of 24.3 mass%.

(Toner preparation)
Crystalline polyester resin particle dispersion 15 parts by weight Amorphous polyester resin particle dispersion 80 parts by weight Colorant dispersion 18 parts by weight Release agent dispersion 18 parts by weight Ion exchange so that the above components have a solid content of 16% by weight Water was added, and the mixture was thoroughly mixed and dispersed with an Ultra Turrax T50 in a round stainless steel flask. Next, 0.36 parts by mass of polyaluminum chloride was added thereto, and the dispersion operation was continued with an ultra turrax. The flask was heated to 47 ° C. with stirring in an oil bath for heating. After maintaining at 47 ° C. for 60 minutes, 46 parts by mass of the amorphous polyester resin particle dispersion was gently added thereto. Thereafter, the pH of the system was adjusted to 9.0 with a 0.55 mol / L sodium hydroxide aqueous solution, and then the stainless steel flask was sealed, and heated to 90 ° C. while continuing stirring using a magnetic seal. Hold for 5 hours. When the particle size at this time was measured, the volume average particle size was 2.3 μm, the volume average particle size distribution index GSDv was 1.24, and the number average particle size distribution index GSDp was 1.30. After completion of the treatment, the mixture was cooled, filtered, sufficiently washed with ion exchange water, and then subjected to solid-liquid separation by Nutsche suction filtration. This was further redispersed in 3 L of ion exchange water at 40 ° C., and stirred and washed at 300 rpm for 15 minutes. This was further repeated 5 times, and when the electrical conductivity of the filtrate reached 9.7 μS / cm, solid-liquid separation was performed by Nutsche suction filtration using No4A filter paper to obtain toner particles.

(Surface modification of toner particles)
100 parts by mass of the obtained toner particles were added to 900 parts by mass of ion-exchanged water to prepare a slurry (solid content concentration 10% by mass). The slurry was adjusted to pH 4 by adding 1N hydrochloric acid, stirred for 10 minutes, then subjected to solid-liquid separation by centrifugation, and the supernatant was discarded to remove excess acid. Thereafter, 900 parts by mass of ion-exchanged water was added for re-slurry, and this slurry was subjected to polyallylamine PAA-15 (manufactured by Nitto Bo Medical Co., Ltd., in the above formula (1), m = 265, weight average molecular weight 15,000). 10 mass parts of 10 mass% aqueous solution was added, and it stirred for 60 minutes. Thereafter, solid-liquid separation was performed by centrifugation, the supernatant was discarded, and excess polyallylamine was removed. Ion exchange water addition, stirring for 10 minutes, and centrifugation were repeated until the electrical conductivity of the cleaning liquid became 20 μS / cm or less. After filtering using a filter paper (Advantech Co., No. 4A), washing with ion-exchanged water, drying at 35 ° C. for 24 hours (moisture content of 0.5 mass%), pulverizing, and surface-modified toner particles Obtained.

(Preparation of developer)
10 parts by mass of the surface-modified toner particles obtained above were mixed with 190 parts by mass of a positive charging carrier (Japanese Imaging Society standard carrier P-01) to obtain a developer.

[Example 2]
Surface-modified toner particles and a developer were obtained in the same manner as in Example 1 except that the amount of polyallylamine PAA-15 used was changed to 0.1 parts by mass.

[Example 3]
Surface-modified toner particles and a developer were obtained in the same manner as in Example 1 except that the amount of polyallylamine PAA-15 was changed to 3 parts by mass.

[Example 4]
In the same manner as in Example 1, except that the polyallylamine was changed to PAA-25 (manufactured by Nitto Bo Medical Co., Ltd., m = 440, weight average molecular weight 25,000 in the above formula (1)), surface modified toner particles, A developer was obtained.

[Example 5]
Surface-modified toner particles in the same manner as in Example 1 except that polyallylamine was changed to PAA-08 (manufactured by Nitto Bo Medical Co., Ltd., m = 140, weight average molecular weight 8,000 in the above formula (1)). A developer was obtained.

[Example 6]
In the same manner as in Example 1, except that polyallylamine was changed to PAA-05 (manufactured by Nitto Bo Medical Co., Ltd., m = 90, weight average molecular weight 5,000 in the above formula (1)), surface modified toner particles, A developer was obtained.

[Example 7]
In the same manner as in Example 1, except that polyallylamine was changed to PAA-03 (manufactured by Nitto Bo Medical Co., Ltd., m = 55, weight average molecular weight 3,000 in the above formula (1)), surface modified toner particles, A developer was obtained.

[Example 8]
In the same manner as in Example 1, except that the polyallylamine was changed to PAA-01 (manufactured by Nitto Bo Medical Co., Ltd., m = 30, weight average molecular weight 1,600 in the above formula (1)), surface modified toner particles, A developer was obtained.

[Example 9]
PAA-1112 (manufactured by Nitto Bo Medical, in the above formula (2), R ¹ = methyl group, R ² = methyl group, m = 2, n = 1, l = 5, weight average molecular weight 1,000) Surface-modified toner particles and a developer were obtained in the same manner as in Example 1 except that.

[Example 10]
Except for changing polyallylamine to PAA-N5000 (manufactured by Nitto Bo Medical Co., Ltd., m = 2, n = 1, l = 70, weight average molecular weight 15,000 in the above formula (3)), the same procedure as in Example 1 was performed. Thus, surface modified toner particles and a developer were obtained.

[Example 11]
Except for changing polyallylamine to PAA-U5000 (manufactured by Nitto Bo Medical Co., Ltd., m = 2, n = 1, l = 70, weight average molecular weight 15,000 in the above formula (4)), the same procedure as in Example 1 was performed. Thus, surface modified toner particles and a developer were obtained.

[Example 12]
(Toner production)
Toner particles using styrene / acrylic resin as a binder resin were prepared by an emulsion polymerization method.

  In the same manner as in Example 1, the surface of the toner particles was modified to prepare a developer.

[Example 13]
Surface-modified toner particles and a developer were obtained in the same manner as in Example 1 except that the amount of polyallylamine PAA-15 used was changed to 0.05 parts by mass.

[Example 14]
Surface-modified toner particles and a developer were obtained in the same manner as in Example 1 except that the amount of polyallylamine PAA-15 was changed to 3.5 parts by mass.

[Example 15]
Toner particles were prepared in the same manner as in Example 1 except that the acid value of the binder resin and the polyester resin to be used was 1 mg KOH / g, and the surface of the toner particles was modified to prepare a developer.

[Example 16]
(Toner production)
Toner particles were prepared in the same manner as in Example 1 except that the acid value of the binder resin and the polyester resin to be used was 30 mg KOH / g, and the surface of the toner particles was modified to prepare a developer.

[Example 17]
(Toner production)
Toner particles were prepared in the same manner as in Example 1 except that the acid value of the binder resin and the polyester resin to be used was 0.7 mgKOH / g, and the surface of the toner particles was modified to prepare a developer.

[Example 18]
(Toner production)
Toner particles were prepared in the same manner as in Example 1 except that the acid value of the binder resin and the polyester resin to be used was 35 mg KOH / g, and the surface of the toner particles was modified to prepare a developer.

[Example 19]
Synthesis was carried out with reference to JP-A-60-104107, JP-A-60-192715, JP-A-61-60703, etc., and in the above formula (1), m = 490, weight average molecular weight 28000 Surface-modified toner particles and a developer were obtained in the same manner as in Example 1 except that polyallylamine was used.

[Example 20]
Synthesis was carried out with reference to JP-A-60-104107, JP-A-60-192715, JP-A-61-60703, etc., and in the above formula (1), m = 12, weight average molecular weight 700 Surface-modified toner particles and a developer were obtained in the same manner as in Example 1 except that polyallylamine was used.

[Comparative Example 1]
Toner particles and a developer were obtained in the same manner as in Example 1 except that the surface modification of the toner particles with polyallylamine PAA-15 was not performed.

[Comparative Example 2]
Surface-modified toner particles and development were carried out in the same manner as in Example 1 except that a quaternary ammonium salt-containing positive charge control agent BONTRON P-51 (manufactured by Orient Chemical Industries) was used instead of polyallylamine PAA-15. An agent was obtained.

(Detection of polyallylamine)
Detection of polyallylamine in the surface modified toner particles was performed using an infrared spectrophotometer (FT / IR-4100, manufactured by JASCO Corporation). Detection of polyallylamine, ^{1650 cm} -1 in the infrared absorption spectrum, an absorption characteristic in the vicinity of 1570 cm ^-1. In addition, the presence of polyallylamine on the surface of the toner particles means that a fluorescent dye, fluorescein isothiocyanate (FITC), is adsorbed to the polyallylamine present on the toner surface, and an ultraviolet-visible near-infrared spectrophotometer (manufactured by Shimadzu Corporation) UV-1800 type).

  The surface-modified toner particles can be collected by removing the carrier liquid from the developer. The collected toner particles are washed with alcohols to remove the polyallylamines on the surface of the toner particles, and the weight of the polyallylamine is measured using high-performance liquid chromatography (HLC-8320GPC type, manufactured by Tosoh Corporation) after washing. The average molecular weight Mw is obtained, FITC is adsorbed, the addition amount of polyallylamine is obtained using an ultraviolet-visible near-infrared spectrophotometer (manufactured by Shimadzu Corporation, UV-1800 type), and a potentiometric titrator by the method of JIS K0070. The acid value of the binder resin is determined using (Hiranuma Sangyo, COM-1700 type).

(Evaluation)
[Developability]
In the environment of 25 ° C. and 50% RH, each developer of the example and the comparative example was modified so that the DocuCentreColor400CP remodeling machine manufactured by Fuji Xerox Co., Ltd. ), And 10,000 white solid images are output on A4 paper (J paper) manufactured by Fuji Xerox Co., Ltd., then a solid batch of 5 cm × 2 cm is developed, and the developing toner on the surface of the photoreceptor is developed. An image was collected using the adhesiveness of the adhesive tape surface, and its mass (W1) was measured. Next, the same developed toner image was transferred to the surface of paper (J paper), and the mass (W2) of the transferred image was measured. From these results, the transfer efficiency was determined by the following formula and evaluated based on the following four criteria.
Transfer efficiency (%) = (W2 / W1) × 100
A: Transfer efficiency is 95% or more B: Transfer efficiency is 87.5% or more and less than 95% C: Transfer efficiency is 80% or more and less than 87.5% D: Transfer efficiency is less than 80%

[Positive charge]
Each developer in Examples and Comparative Examples is filled in the above-described developing device, and the charge amount of the toner that is regulated by the regulating blade of the developing device and conveyed to the photosensitive member is analyzed for the toner on the developing roller. Evaluated by. The charge amount was measured by an E-SPART analyzer manufactured by Hosokawa Micron Corporation. The measurement conditions were a suction flow rate of 0.2 liters / minute, a dust collection air flow rate of 0.6 liters / minute, a blowing nitrogen gas pressure of 0.02 MPa, and the charge amount (Q / m) for each toner was measured. The charge amount distribution was obtained with a toner count of 3,000. The uniformity of the toner charge amount is a value obtained by dividing the maximum frequency charge amount (Q1 / m1) and the measured total toner charge amount by the measurement count (number) in the number distribution of the charge amount per toner. The smaller the absolute value of the difference from Q2 / m2), the more uniform the charge amount distribution, and the larger the absolute value, the more nonuniform. Evaluation was performed based on the following four criteria.
A: Absolute value of difference is 0.8 or less B: Absolute value of difference is 0.8 or more and less than 1.0 C: Absolute value of difference is 1.0 or more and less than 1.5 D: Absolute value of difference is 1. 5 or more

[Saturation charge in high temperature and high humidity environment]
In an environmental test room at a temperature of 30 ° C. and a humidity of 80%, 100 parts by mass of standard carrier P-01 (Japan Imaging Society) and 5 parts by mass of each toner of the examples and comparative examples were left for 1 hour. The pot was charged and rotated and mixed at a constant rotation speed with a ball mill installed in an environmental test chamber. The developer saturated charge amount (μC / g) after stirring for 20 minutes from the start of rotation was measured with a blow-off device, and the difference between the charge amount after 1 minute and the charge amount after 20 minutes was determined. Evaluation was based on criteria.
A: Charge amount difference is less than ± 3 μC B: Charge amount difference is ± 3 μC or more and less than ± 5 μC C: Charge amount difference is ± 5 μC or more and less than ± 7 μC D: Charge amount difference is ± 7μC or more

[Saturation charge in low temperature and low humidity environment]
In an environmental test room at a temperature of 10 ° C. and a humidity of 30%, 100 parts by mass of standard carrier P-01 (Japan Imaging Society) and 5 parts by mass of each toner of the examples and comparative examples were left for 1 hour. The pot was charged and rotated and mixed at a constant rotation speed with a ball mill installed in an environmental test chamber. The developer saturated charge amount (μC / g) after stirring for 20 minutes from the start of rotation was measured with a blow-off device, and the difference between the charge amount after 1 minute and the charge amount after 20 minutes was determined. Evaluation was based on criteria.
A: Charge amount difference is less than ± 3 μC B: Charge amount difference is ± 3 μC or more and less than ± 5 μC C: Charge amount difference is ± 5 μC or more and less than ± 7 μC D: Charge amount difference is ± 7μC or more

[Cover]
Each developer in Examples and Comparative Examples was filled in the above-described developing devices and set in the image forming apparatus. In the image forming apparatus described above, 10 sheets of a predetermined pattern (5% printing) are continuously printed on A4 paper (J paper) manufactured by Fuji Xerox Co., Ltd., and then transferred to an unprinted portion of the recording medium. The degree of toner particle adhesion was visually confirmed and evaluated according to the following four-stage criteria.
A: Toner particles cannot be confirmed in the non-printed portion B: Toner particles slightly adhere to the non-printed portion C: Toner particles slightly adhere to the non-printed portion D : A large amount of toner particles adhere to the unprinted area.

  Thus, in the example using the developer containing toner particles whose surface was modified with polyallylamines, the positive chargeability was excellent as compared with the comparative example. Further, in the examples, compared with the comparative examples, the developability was excellent, the charge amount under the high temperature and high humidity environment and the low temperature and low humidity environment was appropriate, and the occurrence of fog was small.

  DESCRIPTION OF SYMBOLS 1 Process cartridge, 3 Image forming apparatus, 10 Charging apparatus, 12 Exposure apparatus, 14 Photoconductor, 16 Developing apparatus, 18 Transfer roll, 20 Cleaning blade, 22 Fixing roll, 24 Recording paper.

Claims (8)

Including at least a binder resin and a colorant,
A dry toner for positive charging, wherein the surface of the toner particles is surface-modified with polyallylamines. The polyallylamine is at least one of the polyallylamine represented by the following formula (1), the polyallylamine represented by the formula (2), the polyallylamine represented by the formula (3), and the polyallylamine represented by the formula (4). The positively chargeable dry toner according to claim 1, wherein the dry toner is positively charged.

(1)
(In Formula (1), m is an integer of 2 or more and 500 or less.)

(2)
(In Formula (2), R ¹ and R ² each independently represent a hydrogen atom or an aliphatic hydrocarbon group having 1 to 20 carbon atoms, and m and n are each independently 1 to 20) (It is an integer. L is an integer of 2 to 20.)

(3)
(In Formula (3), m and n are each independently an integer of 1 to 100. l is an integer of 2 to 200.)

(4)
(In Formula (4), m and n are each independently an integer of 1 to 100. l is an integer of 2 to 200.)   The dry toner for positive charging according to claim 1, wherein the polyallylamine has a weight average molecular weight in a range of 1,000 to 25,000.   A developer comprising the positively chargeable dry toner according to claim 1.   A developer cartridge containing the developer according to claim 4.   A process cartridge containing the developer according to claim 4. An image carrier,
Latent image forming means for forming a latent image on the surface of the image carrier;
Developing means for developing the latent image formed on the surface of the image carrier with the developer according to claim 4 to form a toner image;
Transfer means for transferring the toner image formed on the surface of the image carrier to a transfer target;
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 developer according to claim 4 to form a toner image;
A transfer step of transferring the toner image formed on the surface of the image carrier to a transfer target;
An image forming method comprising:

Images