JPS62187863A - Carrier - Google Patents

Abstract

PURPOSE:To obtain a high image density by coating iron oxide powder with a cured material of a copolymer having a carboxyl group and/or hydroxyl group and melamine resin. CONSTITUTION:The iron oxide powder is coated with the cured material of the copolymer having the carboxyl group and/or hydroxyl group and melamine resin. The copolymer having the carboxyl group and/or hydroxyl group refers to a copolymer of a vinyl monomer having the carboxyl group and/or hydroxyl group and other vinyl monomer. The vinyl monomer having the carboxyl group and/or hydroxyl group includes an acrylic acid, etc. These monomers are so used that the hydroxyl value and cargboxyl value of the copolymer or the sum total thereof is more preferably 20-200(KOHmg/g).

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a carrier in a developer for electrophotography, electrostatic recording, etc.

(Prior Art) Two-component developers used in computer output devices (hereinafter abbreviated as printers) and general office copying machines (hereinafter abbreviated as copiers) are composed of carrier and toner. The carrier and toner are mixed. Due to friction over time, they are charged with equal amounts and opposite signs, and the Coulomb force acting between these electrostatic charges causes the toner to adhere to the carrier surface.When this two-component developer comes into contact with the photoreceptor, it The toner migrates to the upper contrast potential area to form a toner layer.

The carrier used in the two-component developer is the Tokuko Kokko 1986-11.
As disclosed in Japanese Patent Application Laid-open No. 143, Japanese Patent Application Laid-Open No. 49-51951, Japanese Patent Application Laid-open No. 59-53856, iron oxide powders are mostly in various shapes such as spherical, spongy, and flat shapes.

Spherical carriers are used for printers, where most of the output information is line images, and sponge-like or flat carriers are used for copiers, which output many solid images, and each carrier is used depending on the purpose.

Furthermore, in order to achieve high image density, the thickness of the oxide film on the surface layer of the carrier is adjusted.

That is, if the oxide film on the carrier surface layer is made thinner, the carrier resistance will be lowered, and the developing electric field between the developer and the photoreceptor will be strengthened, thereby providing a high image density.

(Problems to be Solved by the Invention) Carriers with thinner coatings in order to obtain the above-mentioned high image density have a problem in that they have weak resistance to friction and impact and cannot withstand repeated use.

The second object of the present invention is to provide a carrier that solves these problems and provides high image density. Another object is to provide a carrier that can provide high image density for both line images and solid images even when using a spherical carrier that is generally said to be difficult to reproduce solid images. Another purpose is to provide a long-life carrier.

(Means for Solving the Problems) The present invention relates to a carrier formed by coating iron oxide powder with a cured product of a copolymer having a carboxyl group and/or a hydroxyl group and a melamine resin.

In the present invention, a copolymer having a carboxyl group and/or a hydroxyl group is a copolymer of a vinyl monomer having a carboxyl group and/or a hydroxyl group and another vinyl monomer.

Examples of the vinyl monomer having a carboxyl group and/or hydroxyl group include acrylic acid, methacrylic acid, itaconic acid, maleic acid, and hexamaric acid.

General formula % formula %) (in the formula 1 (, 1 is H or methyl group R2 has 1 to 1 carbon atoms)
4 is a divalent hydrocarbon group, 几3 is 1 to 4 having 1 to 10 carbon atoms
a valent hydrocarbon group, n indicates the number of carboxyl group substitutions,
(an integer from 1 to 3), 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, hydroxybutyl acrylate, 2-hydroxy-3-phenyloxypropyl acrylate, 2-hydroxyethyl methacrylate , 2-hydroxypropyl methacrylate.

Examples include hydroxybutyl methacrylate and 2-hydroxy-3-phenyloxypropyl methacrylate.

These monomers preferably have a hydroxyl value, a carboxyl value, or a total of these in the copolymer from 10 to 300.
(KOHI119/9), particularly preferably 20 to 20
0 (KOHff1g/9n). If this value is too small, the reaction with the melamine resin will be insufficient, and the cured film will be easily destroyed by impact, friction, etc.; if it is too large, the cured product film will be easily destroyed. After the reaction with the melamine resin, unreacted hydroxyl groups and/or carboxyl groups increase, and the resin becomes hygroscopic.

Other vinyl monomers include styrene, α-methylstyrene, p-methylstyrene, pt-butylstyrene, p-chlorostyrene and other styrene derivatives, methyl methacrylate, ethyl methacrylate, propyl methacrylate, and methacrylate. butyl methacrylate, pentyl methacrylate, hexyl methacrylate, heptyl methacrylate, octyl methacrylate, nonyl methacrylate, decyl methacrylate.

Undecyl methacrylate, dodecyl methacrylate.

Glycidyl methacrylate, methoxyethyl methacrylate, propoxyethyl methacrylate, butoxyethyl methacrylate, methoxydiethylene glycol methacrylate, ethoxydiethylene glycol methacrylate, methoxyethylene glycol methacrylate, butoxytriethylene glycol methacrylate, methoxydipropylene glycol methacrylate, methacrylate Phenoxyethyl acid.

Phenoxydiethylene glycol methacrylate.

Phenoxytetraethylene glycol methacrylate, benzyl methacrylate, cyclohexyl methacrylate, tetrahydrofurfuryl methacrylate.

Dicyclopentenyl methacrylate, dicyclopentenyloxyethyl methacrylate, N-vinyl methacrylate
2-pyrrolidone, methacrylonitrile, methacrylamide, N-methylolmethacrylamide, ethylmorpholine methacrylate, diacetone acrylamide, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, pentyl acrylate, hexyl acrylate, Heptyl acrylate, octyl acrylate.

Nonyl acrylate, decyl acrylate, undecyl acrylate, dodecyl acrylate, glycidyl acrylate,
Methoxyethyl acrylate, propoxyethyl acrylate, butoxyethyl acrylate, methoxydiethylene glycol acrylate.

Ethoxydiethylene glycol acrylate, methoxyethylene glycol acrylate, butoxytriethylene glycol acrylate, methoxydiglobylene glycol acrylate, phenoxyethyl acrylate, phenoxydiethylene glycol acrylate, phenoxytetraethylene glycol acrylate, benzyl acrylate, cyclohexyl acrylate, Tetrahydrofurfuryl acrylate, dicyclopentenyl acrylate, dicyclopentenyloxyethyl acrylate, N-vinyl-2-picridone acrylate, glycidyl acrylate, acrylonitrile, acrylamide, N-methylol acrylamide, diacetone acrylamide, ethyl acrylate Vinyl monomers having one vinyl group in each molecule such as morpholine, vinylpyridine, divinylbenzene, reaction products of glycol and methacrylic acid or acrylic acid 2 For example, ethylene glycol dimethacrylate.

1.3-Butylene glycol dimethacrylate, 1°4
- Phtanediol dimethacrylate, 1,5-bentanediol dimethacrylate, 1,6-hexanediol diacrylate, neopentyl glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, tripropylene glycol dimethacrylate , hydroxypiparic acid neopentyl glycol ester dimethacrylate, trimethylolethane trimethacrylate, trimethylolpropane trimethacrylate, pentaerythritol tetramethacrylate, trismethacryloxyethyl phosphate, tris(methacryloyloxyethyl)in cyanurate, ethylene glycol diacrylate , 1.3-butylene glycol diacrylate, 1.4-butanediol diacrylate, 1.5-bentanediol diacrylate.

1.6-hexanediol diacrylate, neopentyl glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, polyethylene glycol diacrylate, tripropylene diacrylate, hydroxypivalate neopentyl glycol diacrylate, trimethylolethane triacrylate, Trimethylolpropane triacrylate.

Pentaerythritol tetraacrylate, trisacryloxyethyl phosphate, tris(methacryloyloxyethyl)isocyanurate, halfesterized product of glycidyl methacrylate and methacrylic acid or acrylic acid, halfesterized product of bisphenol-type epoxy resin and methacrylic acid or acrylic acid, acrylic acid No.-7 of glycidyl and methacrylic acid or acrylic acid
Examples include vinyl monomers having two or more vinyl groups in one molecule, such as esterified products.

Among these other vinyl monomers, vinyl monomers having one vinyl group in one molecule.

Styrene, styrene derivatives, methacrylic esters, acrylic esters, etc. are preferred, especially 1 to 1 to
Alkyl esters of methacrylic acid or acrylic acid having 5 carbon atoms are preferred. As vinyl monomers having two or more vinyl groups in one molecule, divinylbenzene, dimethacrylates and diacrylates made of methylene glycol having 2 to 6 carbon atoms, and the like are preferred.

Among these vinyl monomers, carboxyl groups and/or
Alternatively, the vinyl monomer having a human myxyl group has a copolymer having a hydroxyl value, a carboxyl value, or the sum of these, preferably 10 to 300 (KOHmQ/9), preferably 20 to 200% (KOHmQ/g). used to become If this value is too small, the cured film with the melamine resin tends to have low resistance to impact or friction.

If it is too large, the hygroscopicity of the film tends to increase.

Furthermore, among the above vinyl monomers, the compound having two or more vinyl groups is preferably used in an amount of 0 to 20% by weight.

These vinyl monomers are copolymerized by known methods such as @turbidity polymerization, emulsion polymerization, solution polymerization, and bulk polymerization.

The copolymer having a carboxyl group and/or hydroxyl group of the present invention has an average molecular weight of s, o o o ~
It is preferably 700,000 (standard polystyrene equivalent value determined by gel permeation chromatography).

The melamine resin of the present invention is a combination of 2,4,6-triamino-1,3,5-triazine (melamine L), 2,4-diamino-1,3,5-triazine (guanamine or a substituted product thereof, and formaldehyde). These are an adduct or an addition condensate and an alkyl etherified product of this adduct or addition condensate.The alkyl etherified product is the above adduct or addition condensate and methanol.

It is obtained by reacting with a lower alcohol such as butanol. As the melamine resin, it is preferable to use an alkyl ether compound because it is easier to handle before curing. Examples of melamine resins include monomethylolmelamine to hexamethylolhelamine, monomethoxymethylmelamine to hexamethoxymethylmelamine, monoethoxymethylmelamine to hexaethoxymethylmelamine, monopropoxymethylmelamine to hexiteproboxymethylmelamine, and monopropoxymethylmelamine to hexateproboxymethylmelamine. Phytoxymethylmelamine - Hexabutoxymethylmelamine, dimethoxymethyldibutoxymethylmelamine, trimethoxymethyldibutoxymethylmelamine, tetramethoxymethyldibutoxymethylmelamine, tetramethoxymethylmonobutoxymethylmelamine, monomethylolbenzoguanamine, tetramethylolbenzoguanamine, monomethoxy Methylbenzoguanamine - tetramethoxymethylbenzoguanamine, monoethoxymethylbenzoguanamine - tetraethoxymethylbenzoguanamine, monoproboxymethylpenzoguanamine - tetraproboxymethylpenzoguanamine,
Monophthoxymethylpenzoguanamine to tetrabutoxymethylbenzoguanamine, dimethoxymethyldibutoxymethylbenzoguanamine, trimethoxymethylbutoxymethylbenzoguanamine, etc. may have two or more ashes, melamine nuclei, or benzoguanamine nuclei.

Further, as the alkyl etherified product, those having a methyl ether group are particularly preferred from the viewpoint of 9-reactivity. In addition, from the viewpoint of the toughness of the resulting resin, those having two or more alkyl ether groups are preferred. These melamine resins may be used alone, or in combination of two or more.

In addition, the ratio of the copolymer having carboxyl groups and/or hydroxyl groups to the melamine resin is such that carboxyl groups and/or hydroxyl groups/alkoxyl groups are 7/3 to 3/7 (equivalent ratio). , preferably 6/4
~476 (equivalent ratio).

If they are mixed outside this range, the strength of the coating will decrease, and it will tend to be unable to withstand impact and friction, resulting in a shortened service life.

There are two primary methods for forming a coating of cured material on iron oxide powder.

That is, a method in which iron oxide powder is immersed in a solution in which the copolymer and melamine resin are dissolved in an organic solvent such as methylene chloride, methyl ethyl ketone, cyclohexanone, tetrahydrofuran, ethyl acetate, butyl acetate, and then taken out and dried. There are methods such as spraying the above solution onto iron oxide powder in a fluidized bed and drying it. In this case, the total amount of the copolymer and melamine resin in the solution is preferably 5 to 25% by weight. For drying, after volatilizing the solvent at 30 to 60°C,
It is preferable to carry out the curing reaction at 90 to 150°C.

Preferably, the reaction is carried out in a fluidized bed, hot air tunnel, or the like.

The carrier according to the present invention is combined with one of various toners to form a developer.

As a toner, 4? There is no limit to 1, for example.

A material containing a binder resin such as a vinyl copolymer, polyester resin, or epoxy resin, a colorant, and other additives as necessary is used.

Vinyl monomer that is the raw material for the above vinyl copolymer! : Styrene, styrene derivatives such as α-methylstyrene, p-methylstyrene, p-t-7′-methylstyrene, and p-chlorostyrene, methacrylic acid, methyl methacrylate, and ethyl methacrylate.

Propyl methacrylate, butyl methacrylate, pentyl methacrylate, hexyl methacrylate, heptyl methacrylate, octyl methacrylate, nonyl methacrylate,
Decyl methacrylate, undecyl methacrylate, dodecyl methacrylate, methoxyethyl methacrylate, propoxyethyl methacrylate, butoxyethyl methacrylate, methoxydiethylene glycol methacrylate, ethoxydiethylene glycol methacrylate, methoxytriethylene glycol methacrylate, butoxytriethylene glycol methacrylate , methoxydipropylene glycol methacrylate, phenoxyethyl methacrylate, phenoxydiethylene glycol methacrylate, methacrylic ff mitsuenoxytetraethylene glycol, benzyl methacrylate.

Cyclohexyl methacrylate, tetrahydrofurfuryl methacrylate, dicyclopentenyl methacrylate, dicyclopentenyloxyethyl methacrylate, N-vinyl-2-picridone methacrylate, methacrylonitrile,
methacrylamide, N-methylolmethacrylamide,
Ethylmorpholine methacrylate, propylmorpholine methacrylate, butylmorpholine methacrylate, acrylic acid.

Diacetone acrylamide, methyl acrylate.

Ethyl acrylate, propyl acrylate, butyl acrylate, pentyl acrylate, hexyl acrylate, heptyl acrylate, octyl acrylate, nonyl acrylate, decyl acrylate, undecyl acrylate, dodecyl acrylate, methoxyethyl acrylate, acrylic Propoxyethyl acrylate, butoxyethyl acrylate, methoxydiethylene glycol acrylate, ethoxydiethylene glycol acrylate, methoxyethylene glycol acrylate, butoxytriethylene glycol acrylate, methoxydipropylene glycol acrylate, phenoxyethyl acrylate, phenoxydiethylene glycol acrylate, acrylic Acid phenoxytetraethylene glycol, benzyl acrylate, cyclohexyl acrylate, tetrahydrofurfuryl acrylate, dicyclopentenyl acrylate, dicyclopentenyloxyethyl acrylate, N-vinyl-2-pyrrolidone acrylate, hydroxyethyl acrylate, acrylic Hydroxyglobil acid, hydroxybutyl acrylate, acrylic acid 2
-Hydroxy-3-7dynyloxyglobil, glycidyl acrylate, acrylonitrile, acrylamide, N
- Ruhinyl monomers having one vinyl group in each molecule such as methylol acrylamide, diacetone acrylamide, ethylmorpholine acrylate, propylmorpholine acrylate, butylmorpholine acrylate, vinylhyridine, divinylbenzene, glycol and methacrylate
R or reaction product 2 with acrylic acid, such as ethylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, 1,4-butanediol dimethacrylate, 1°5-bentanediol dimethacrylate, 1,6-hexane Diol diacrylate, neopentyl glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, tripropylene glycol dimethacrylate, hydroxypivalic acid neopentyl glycol ester dimethacrylate, trimethylolethane trimethacrylate, trimethylolpropane Trimethacrylate, pentaerythritol trimethacrylate, pentaerythritol tetramethacrylate, trismethacryloxyethyl phosphate, bis(methacryloyloxyethyl)hydroxyethyl isocyanurate, tris(methacryloyloxyethyl)in cyanurate, ethylene glycol diacrylate, 1゜3 -butylene glycol diacrylate, 1,4-butanediol diacrylate, 1
．． 5-bentanediol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, polyethylene glycol diacrylate, tripropylene diacrylate, hydroxypivalic acid neopentyl glycol diacrylate , trimethylolethane triacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetramethacrylate, trisacryloxyethyl phosphate, bis(methacryloyloxyethyl) hydroxyethyl inocyanurate, tris(methacryloyloxyethyl) ) incyanurate, etc.

Furthermore, as a monomer that becomes a raw material for the vinyl copolymer, general formula (I): H (wherein R1 represents hydrogen or a methyl group, R represents an alkylene group having 1 to 4 carbon atoms, Atom i1~
4 vinyl monomers representing an alkyl group are preferred,
Specifically, 2-hydroxypropyl methacrylate, 2-hydroxybutyl methacrylate, 3-hydroxybutyl methacrylate, 2-hydroxypropyl acrylate,
Examples include 2-hydroxybutyl acrylate and 3-hydroxybutyl acrylate. These secondary hydroxyl group-containing monomers play a role in imparting adhesion resistance (hereinafter referred to as PVC resistance) to soft vinyl chloride polymers, and are components that dramatically improve toner performance. be.

In particular, 2-hydroxypropyl methacrylate is used because it is easy to obtain resin physical properties suitable for toners and to obtain a copolymer having suitable vinyl chloride resistance.

2-hydroxypropyl acrylate is preferred.

These can be used alone or in combination. The vinyl monomer has a vinyl copolymer having a hydroxyl value of 50 to 250.
(KOHrNJ/g), preferably 80-200 (
KOHmg/g).

Outside this range, problems such as poor vinyl chloride resistance and decreased charging performance due to moisture absorption occur.

Further, the glass transition temperature of the vinyl copolymer is preferably 4
The type and proportion of vinyl monomers must be taken into consideration so that the temperature is 0 to 90°C, particularly preferably 45 to 80°C. Therefore, in particular, (a) 40 to 85% by weight of styrene and/or methyl methacrylate, (b) the general formula (1)
) 15 to 60% by weight of vinyl nitrate represented by (c)
A copolymer made of 0 to 20% by weight of other copolymerizable vinyl monomers and blended with components (a) to (c) in a total amount of 100% by weight also has vinyl chloride resistance. It is particularly preferable.

Component (a) plays the role of imparting a high glass transition temperature and appropriate brittleness.

The coloring agents include carbon black, acetylene black, Hansa Yellow G, cadmium yellow, molybdenum orange, permanent orange, rhodamine lake B, fast violet B, methyl violet lake, navy blue, phthalocyanine blue, chrome green, and hickment green B. , zinc oxide, titanium oxide,
iron oxide.

Nigrosine dye, methylene blue, rose bengal, quinoline yellow, ultramarine blue.

Chrome Yellow, Aniline Blue, Calco Oil Blue, Rhodamine 6G Lake, Watching Red Barium, Watching Red Strontium, Malachite Green Octylate. There are conventionally known pigments or dyes such as DuPont Oil Red and mixtures thereof, and these are preferably used in the toner by appropriately selecting an amount within the range of 1 to 60]i.

The following additives can be included in the toner.

As an anti-offset agent, Hiwax 110P, 2
10P, 220P, 320P, 410P.

420F, 220MP, 405MP, 4202E.

4052E, 1105A, 2203A (manufactured by Mitsui Petrochemical Co., Ltd., trademark), polyethylene 6A (manufactured by Allied Chemical Co., Ltd., trademark), Viscol 660 P.

550P, 330P, Sunwax 131P.

151F, 161P, 165P, 171P, E300,
E250P (manufactured by Sanyo Chemical Industries, Ltd.)

Trademark L A-C polyethylene 629,655°680.
690,617,6A,7A,712°725.735
, 540, 400, 403, 430 (manufactured by Toyo Chemicals Co., Ltd., trademark), etc., and Nilapol 2057 S.

Diene resins such as 2007J (manufactured by Nippon Zeon ■, trademark), and lower alcohol esters of fatty acids such as butyl stearate and propyl stearate.

Casta Wax A (manufactured by Kao Soap Co., Ltd., trademark).

Polyhydric alcohol esters of fatty acids such as diamond wax (manufactured by Shin Nippon Rika Co., Ltd., trademark), palm acetate (manufactured by Nippon Oil & Fats Co., Ltd., trademark), Hoechst wax E.

Hoechst Wax-P (manufactured by Hoechst, trademark).

Carnauba wax (■Higher alcohol ester of fatty acids such as manufactured by Noda Wax, Bisamide Plus) 7CI
- (manufactured by Nitto Kagaku Co., Ltd., trademark), Amide 6L, 78 and 6
H (manufactured by Yoken Fine Chemical Co., Ltd.).

Alkylene bis fatty acid amide compounds such as Hoechst Wax C (manufactured by Hoechst, trademark), zinc stearate, calcium stearate, magnesium stearate, barium stearate.

Fatty acid metal salts such as copper stearate, aluminum stearate, zinc oleate, magnesium oleate, zinc caprylate, magnesium caprylate, zinc linoleate, and calcium linoleate.

Examples include benzoic acid esters such as pentaerythritol tetrabenzoate.

As a fluidity improver, Aerosil 972゜Silica D
-17, T-805, R-812, R, A-200H,
Bon X-C (manufactured by Nippon Aerosil Co., Ltd., trademark) and Tulanox 500 (Tule.

Examples include hydrophobic silica, fluorocarbon compounds, etc. (manufactured by Co., Ltd., trademark).

In addition, as a fixing property improver, KR-216゜KR-2
20, KR-152, Ni-271°KR-255 (trademarks, manufactured by Shin-Etsu Chemical Co., Ltd.).

Silicone resins such as SR-2400, SR, -2406, 5H-840 (manufactured by Toshi Silicone, trademark), Rig Tool R-70. R-120.几-140, P-2 (
Xylene resins such as Lignite ■, trademark), Epikote 1001, 1004° 1007, YL-903 (
The above-mentioned epoxy resins such as Shell Co., Ltd. (trademark), lactone-modified epoxy resins, polyester resins, phenol resins, amide resins, benzoin, etc. exhibit low melt viscosity, and preferably have a melt viscosity of 1 x 10 at 140°C.
It is a compound of 4 poise or less.

These additives are appropriately selected and used in the range of 90 to 30% by weight of the toner.

As the charge control agent, nigrosine dye, fatty acid-modified nigrosine dye, carboxyl group-containing resin-modified nigrosine dye, tetraalkylammonium halide, trialkylammonium halide.

(In the formula, X represents a halogen, R represents an alkylene group having 1 to 3 carbon atoms, and n represents 0 or 1).

Compound 2 having the structure H'-(CH2C(CN))□ (in the formula, 几' represents hydrogen or an alkyl group having 1 to 3 carbon atoms): Representation.

r represents hydrogen, alkoxy group or phenoxy group), monoalkyltin oxide, dialkyltin oxide, monoaryltin oxide, compound of the formula = (in the formula R4, Rs,
Rs and R7 represent hydrogen, an alkyl group having 1 to 9 carbon atoms, or a substituent having an aromatic ring or a cyclohexene ring, but two or more groups do not represent hydrogen at the same time, and M6 is Cr, Co or Fe. 1M represents hydrogen, potassium,
Compound 2 (representing sodium or fatty acid ammonium)
Formula: (Formula Nakajima and R- represent a fullkylene group, aromatic ring or cyclohexene ring having 1 to 9 carbon atoms, M6 and M
represents the above), metal complexes of azo compounds 9, for example, formula 1: (wherein T, Y and Z represent hydrogen, halogen, carboxyl group, hydroxyl group, nitro group, sulfone group or sulfonamide group) 9M and Me represent the above), tetrathiafulvalene, fine alumina powder, and any conventionally known materials can be used. In terms of uniform dispersibility in resin, fatty acid-modified guccin dyes are recommended as positive charge control agents.

Carboxyl group-containing resin-modified nigrosine dyes and diptyltin oxide are particularly preferred, and as negative charge control agents, metal complexes of azo compounds, metal complexes of 3,5-di-tert-butylsalicylic acid, etc. are particularly preferred, and these are preferably incorporated into the toner. θ~20% by weight, preferably 1~]0! i amount is added.

The toner can be manufactured by a known method.

For example, after pre-mixing the weighed materials using a W cone, blender, Henschel mixer, etc.,
The mixture is kneaded using a Banbury mixer 2 heated roll, an extruder, etc. at a temperature at which the resin melts. After cooling, feather mill, bottle mill.

Coarsely grind with a pulverizer, hammer mill, etc., and finely grind with jet air. Next is AccuCut.

A dry manufacturing method in which particles are distributed to a desired particle size using an Albine classifier or the like, or a wet manufacturing method in which all materials are uniformly dissolved and dispersed in a suitable solvent and then the solvent is removed by spray drying or the like can be applied. The particle size of the toner is desirably in the range of 5 to 30 μm; outside this range, undesirable phenomena such as poor image clarity and image staining due to toner scattering are likely to occur.

(Example> Two examples of the present invention are shown below.

Examples 1 to 6 (1) Preparation of carrier A resin solution prepared by dissolving the copolymer and melamine resin shown in Table 1 in methylene chloride in the formulation shown in Table 1 was added to the resin solution shown in Table 2.
The iron oxide powders shown in Table 2 were put into a sieve and immersed in the combinations shown in Table 2, and the iron oxide powders were stirred. After roasting, remove the iron oxide powder through a sieve.

Iron oxide powder was loaded into a fluidized bed and heated to 40°C for 1 hour, then heated and dried at 130°C for 2 hours. After this.

Aggregated particles of 150 μm or more were removed using a vibrating sieve to obtain a carrier coated with a cured product of the copolymer and melamine resin.

Incidentally, the copolymer having a carboxyl group and/or a hydroxyl group was produced by the method shown below. water 2
00 parts by weight of polyvinyl alcohol as a suspending agent [Denka Popal W-24. A copolymer having a hydroxyl group and/or a carboxyl group shown in Nal to Na6 in Table 1 was added to a solution to which 0.3 parts by weight (manufactured by Denki Kagaku Kogyo ■) was heated to 90°C and stirred. A solution of azobisin butyronitrile as a polymerization initiator added to each of the constituent monomers was added dropwise over 2 hours to perform suspension polymerization to produce a copolymer. Then, while stirring, the temperature was 10 at 90°C.
After keeping warm for a while, return to room temperature and dehydrate.

After drying at 50° C. for 10 hours, copolymers having hydroxyl groups and/or carboxyl groups shown in Table 9 were obtained.

Synthesis Example of Toner Add polyvinyl alcohol as a suspending agent to 200 parts by weight of water [Denka Popal W-24. A solution containing 0.3 parts by weight of Denki Kagaku Jitsugyo ■ was heated to 90°C, and while stirring, added benzoyl peroxide, a polymerization initiator, to the monomer composition shown in Table 3 based on the total amount of monomers. A solution to which 2% by weight was added was added dropwise over 2 hours to perform suspension polymerization, and then the mixture was kept at 90° C. for 10 hours with stirring. Then return to room temperature,
It was dehydrated and dried at 50° C. for 10 hours to obtain copolymers shown in Table 2.

Next, the materials shown in Table 4 were heated at 140°C in a pressurized knee gun.

After melting and mixing for 1 hour, the mixture was finely pulverized using a bottle mill and a jet mill, and classified using a vibrating sieve to obtain a particle size of 5 to 25 ttm.
Toners (A-1 to A-6) were obtained.

Application examples 1 to 3 After preparing a developer by mixing 3 parts by weight of toner and carrier 97 heavy-talk parts in the combinations shown in Table 5, a selenium drum rotating at a speed of 20 cm/sec for two circumferences was uniformly applied with a corona voltage of +6 KV. After charging, a latent image was randomly drawn with a He--Ne laser, and this was subjected to reversal development using the above developer using a magnetic brush method.

Then, it was fixed using a pressurized and heated a-le fixing machine. Table 5 shows the results of measuring the optical reflection density of the nine fixed images obtained using a microphotometer MPM type (Union Chemical @4#).

The print quality after printing 100,000 sheets is the change in print density.

Judgment was made based on increase in fog, etc.

For printing defects caused by soft vinyl chloride, place the printed matter between soft vinyl chloride containing 301℃% dioctyl phthalate.
Temperature 40℃, load 10 g-f/cm2 + test time 2
The test was carried out under conditions of 000 hours.

Application Examples 4 and 5 Printing was carried out in the same manner as in Examples 1 to 3, except that the latent image was drawn using an SF-750 copying machine (manufactured by Sharp ■).

It was measured. The results are shown in Table 5.

Application example 6 K OP C (OrganicP) instead of selenium drum
Printing and measurement were performed in the same manner as in Examples 1 to 3, except that a photoconductor (organic photoconductor) drum was uniformly negatively charged at a corona voltage of 16 Kv. This result is shown in Table 5.
Shown below.

As is clear from Table 5, the use of the carrier of this example resulted in good fixing performance <m image formation.

(determined from square image density and fog density) is obtained,
The offset resistance was also good, and no deterioration in print quality was observed after printing 100,000 sheets. Furthermore, by using the carrier of the present invention in combination with a toner that exhibits adhesion resistance to soft vinyl chloride, it is possible to eliminate printing defects caused by soft vinyl chloride in printed matter.

Comparative application example 1 Carrier C-1 (particles of 74 to 177 μm, content of 9
Printing was carried out in the same manner as in Examples 1 to 3 using a developer prepared by mixing 97.5 parts of spherical iron oxide powder (9-fold ftIJ) and 2.5 parts by weight of toner (A-3).

It was measured. The results are shown in Table 5.

Comparative Example 2 Carrier C-2 (44-105 μmo particles, content 9
94 parts by weight of 9% by weight flat iron oxide powder) and toner (A-
Printing and measurement were carried out in the same manner as in Example 4, except that a developer mixed with 436 parts by weight was used. The results are shown in Table 5.

O Glass transition temperature conditions Thermomechanical analysis method Veneration mode Load 70 g-f Heating rate 10°C/min O Weight average molecular weight was determined by Gelno (Mission chromatography using monodisperse standard polystyrene (manufactured by Waters). It was determined based on the calibration curve obtained.

Margins below (Effects of the Invention) A developer using a carrier coated with a copolymer having a carboxyl group and/or a hydroxyl group and a cured product of a melamine resin according to the present invention can produce high image density. Moreover, by coating with this spherical carrier, which is generally said to be difficult to reproduce solid images, it is possible to increase the image density. Furthermore, this coated carrier has a longer life than conventional carriers.

Claims (1)

[Claims] 1. A carrier obtained by coating iron oxide powder with a cured product of a copolymer having a carboxyl group and/or a hydroxyl group and a melamine resin.