JPH0721654B2 - Developer - Google Patents

Description

TECHNICAL FIELD The present invention relates to a developer used for developing an electrostatic latent image in electrophotography and electrostatic recording. More specifically,
From a positively chargeable carrier consisting of a magnetic core material and a coating resin layer, which is excellent in chargeability, surface contamination resistance, mechanical strength, adhesion between the core and the coating layer, etc., and a toner having excellent negative chargeability. The following developer is provided.

In the conventional electrophotographic method, a photoconductive substance such as selenium is used as a photoconductor, an electric latent image is formed by various means, and a toner is formed on the latent image by a magnetic brush development method or the like. A method of adhering and visualizing is generally adopted.

In this developing process, carrier particles called carrier are used to give an appropriate amount of positive or negative electric charge to the toner. Carriers are generally classified into coated carriers and non-coated carriers, but the former is superior when the life of the developer is taken into consideration, so various types of coated carriers have been developed and put into practical use. .

There are various characteristics required for coat carrier,
Particularly important properties include appropriate chargeability, impact resistance, wear resistance, good adhesion between the core and the coating material, and uniform charge distribution.

Considering the above required characteristics, the conventionally used coat carrier still has a problem to be improved,
The complete one is so far unknown. For example, fluorinated vinyl polymers are excellent in surface stain resistance, but are negatively charged and have a problem in adhesion to the core.Acrylic polymers are mechanically strong, adhesion to the core, Although satisfactory in terms of positive charging property, it is said to have a problem in surface contamination resistance. In any case, it is the current situation that the use of coating materials having advantages and disadvantages is unavoidable.

SUMMARY OF THE INVENTION In view of such a current situation, the inventors of the present invention have conducted various researches and studies to improve the above-mentioned conventional drawbacks, and as a result, it has been found that using a specific coating material improves the required characteristics of the above-mentioned coat carrier. It was found to be effective. Further, the inventors of the present invention have found that a developer comprising a toner having a specific charge control agent dispersed therein and the carrier gives remarkably good results in terms of image, life, etc., and completed the present invention.

Therefore, a main object of the present invention is to provide a novel developer used for developing an electrostatic latent image in electrophotography and electrostatic recording.

Another object of the present invention is that the chargeability of the toner is good, so that the rate of increase in charge is high, and the surface resistance of the carrier is good, so that the amount of charge during running is not reduced, and as a result, fogging occurs early. To provide a developer that does not cause contamination inside the machine.

The developer according to the present invention comprises a carrier having a core material coated with a graft or block copolymer of a fluoroalkyl acrylate or a fluorinated alkyl methacrylate, and a colorant and a negative charge control agent dispersed in a resin. It is characterized in that it becomes toner.

Further, in the present invention, as a negative charge control agent, O, O'-
Particular preference is given to using chromium complex salts of dihydroxyazo dyes.

The coating material used for the developer of the present invention gives a good result even if it is a random copolymer, but the graft stain or block form further improves the surface stain resistance.

The following may be used as the fluorinated alkyl acrylate or fluorinated alkyl methacrylate used in the carrier coating material of the present invention.

That is, acrylic acid or methacrylic acid 1,1-dividoperoperfluoroethyl, 1,1-dihydroperfluoropropyl,
1,1-dihydroperfluorohexyl, 1,1-dihydroperfluorooctyl, 1,1-dihydroperfluorodecyl, 1,1
-Dihydroperfluorolauryl, 1,1,2,2-tetrahydroperfluorobutyl, 1,1,2,2-tetrahydroperfluorohexyl, 1,1,2,2-tetrahydroperfluorooctyl, 1,1,2 , 2-Tetrahydroperfluorodecyl, 1,1,2,2
-Tetrahydroperfluorolauryl, 1,1,2,2-tetrahydroperfluorostearyl, 2,2,3,3-tetrafluoropropyl, 2,2,3,3,4,4-hexafluorobutyl, 1,1 , ω
-Trihydroperfluorohexyl, 1,1, ω-trihydroperfluorooctyl, 1,1,1,3,3,3-hexafluoro-2
-Propyl, 3-perfluorononyl-2-acetylpropyl, 3-perfluorolauryl-2-acetylpropyl, N-perfluorohexylsulfonyl-N-methylaminoethyl, N-perfluorohexylsulfonyl-N-
Butylaminoethyl, N-perfluorooctylsulfonyl-N-methylaminoethyl, N-perfluorooctylsulfonyl-N-ethylaminoethyl, N-perfluorooctylsulfonyl-N-butylaminoethyl, N-perfluorodecylsulfonyl- N-methylaminoethyl,
N-perfluorodecylsulfonyl-N-ethylaminoethyl, N-perfluorodecylsulfonyl-N-butylaminoethyl, N-perfluorolaurylsulfonyl-N-
Examples of each ester compound include methylaminoethyl, N-perfluorolaurylsulfonyl-N-ethylaminoethyl, N-perfluorolaurylsulfonyl-N-butylaminoethyl and the like.

In the present invention, the following components can be used as the component copolymerized with the fluorinated alkyl acrylate or the fluorinated alkyl methacrylate.

That is, styrene, methylstyrene, dimethylstyrene,
Alkyl styrene such as trimethyl styrene, ethyl styrene, diethyl styrene, triethyl styrene, propyl styrene, butyl styrene, hexyl styrene, heptyl styrene, octyl styrene, fluorostyrene,
Chlorostyrene, bromostyrene, dibromostyrene,
Halogenated styrenes such as iodostyrene, styrene monomers such as nitrostyrene, acetylstyrene, methoxystyrene; acrylic acid, methacrylic acid, α-
Addition-polymerizable unsaturated aliphatic monocarboxylic acids such as ethyl acrylic acid, crotonic acid, α-methyl crotonic acid, α-ethyl crotonic acid, isocrotonic acid, tiglic acid, ungeric acid, maleic acid, fumaric acid, itaconic acid, citraconic acid Acids, mesaconic acid, glutaconic acid, dihydromuconic acid and the like addition-polymerizable unsaturated aliphatic dicarboxylic acids; addition-polymerizable unsaturated carboxylic acids and alcohols such as methyl alcohol, ethyl alcohol, propyl alcohol, butyl alcohol, amyl alcohol, hexyl Alkyl alcohols such as alcohol, heptyl alcohol, octyl alcohol, nonyl alcohol, dodecyl alcohol, tetradecyl alcohol, and hexadecyl alcohol, and methoxyethyl alcohol that is a partial alkoxylation of these alkyl alcohols. Alcohol, ethoxyethyl alcohol, ethoxyethoxyethyl alcohol, methoxypropyl alcohol, ethoxypropyl alcohol and other alkoxyalkyl alcohols, benzyl alcohol, phenylethyl alcohol, phenylpropyl alcohol and other aralkyl alcohols, allyl alcohol, crotonyl alcohol, etc. Preferred examples are esterified products with alkenyl alcohols and the like, particularly alkyl acrylates, methacrylic acid alkyl esters (excluding methyl methacrylate), fumaric acid alkyl esters, maleic acid alkyl esters, and the like; Amides and nitriles derived from them; Aliphatic monoolefins such as ethylene, propylene, butene, isobutylene; Vinyl chloride, vinyl bromide Vinyl iodide, 1,2-dichloroethylene, 1,2-dibromoethylene, 1,2-diiodoethylene, isopropenyl chloride, isopropenyl bromide, allyl chloride, allyl bromide, vinylidene chloride, vinyl fluoride, fluorinated Halogenated aliphatic olefins such as vinylidene; 1,3-butadiene, 1,3-pentadiene, 2-methyl-1,3-butadiene, 2,3-dimethyl-1,3-butadiene, 2,4-hexadiene, 3 -Methyl-
Conjugated diene-based aliphatic diolephin such as 2,4-hexadiene; 2-vinylpyridine, 4-vinylpyridine-2 vinyl-6-methylpyridine, 2-vinyl-5-methylpyridine, 4-butenylpyridine, 4-pentylpyridine,
N-vinylpiperidine, 4-vinylpiperidine, 4-vinylpiperidine, N-vinyldihydropyridine, N-vinylpyrrole, 2-vinylpyrrole, N-vinylpyrroline, N-vinylpyrrolidine, 2-vinylpyrrolidine, N
Examples thereof include nitrogen-containing vinyl-based monomers such as -vinyl-2-pyrrolidone, N-vinyl-2-piperidine, and N-vinylcarbazole. These alone or 2
Combinations of more than one species can be used.

The block or graft copolymer of fluorinated alkyl acrylate or fluorinated alkyl methacrylate according to the present invention can be used as a mixture with other coating materials made of various polymers. As specific examples thereof, in addition to polymers (including copolymers) of the above various addition-polymerizable monomers, polyamide, polyester, polycarbonate, silicone resin, cellulose resin and other polycondensation resins can be used.

Examples of the core substance used in the present invention include glass beads, aluminum powder, iron powder, iron oxide powder, carbonyl iron powder, magnetite, nickel, and powders of ferrite and the like, and usually 10 to 50 as a carrier.
A material having a particle size of 0 μ is used.

In the carrier particle of the present invention, the core material as described above is surface-treated with the copolymer according to the present invention as described above, and a coating layer of the copolymer is formed on the surface of the core material by chemical bonding or adsorption. Can be obtained.

For the surface treatment of the core material, for example, the core material is immersed in a solution obtained by dissolving one or a mixture of two or more of the above copolymers in a suitable solvent, and then desolventization,
A method of drying and baking at high temperature, a method of suspending the core material in a fluidized bed, spray-coating the copolymer solution, and drying and baking at high temperature can be used. In these methods, high temperature baking treatment is not always necessary.

The copolymer coating amount is usually 0.05 to 3.0 with respect to the core material.
It is preferably in the weight%.

The carrier of the present invention thus obtained is mixed with the toner of the present invention and used as a developer for developing an electrostatic latent image.

The toner of the present invention may contain various dyes, pigments and carbon black as colorants.

As the charge control agent, copper phthalocyanine or a derivative thereof can be used, but a particularly effective one is a 2: 1 type metal complex salt of O, O'-dihydroxyazo dye, particularly a chromium complex salt. This is represented by the following general formula.

In the above formula, X, Y, Z, X ', Y', and Z'are hydrogen base paper, alkyl group, alkoxy group, nitro group, halogen atom, carbonyl group, hydroxyl group, sulfone group, sulfonamide group, etc., respectively. Represent. Further, Z may be an atomic group bonded to a substituted or unsubstituted phenyl group via an amide bond. A is H, alkali metal,
Represents aliphatic ammonium and pyridinium cations.

As the binder resin used in the toner according to the present invention, styrene resin, styrene-acrylic copolymer, polyolefin, polyester resin, epoxy resin and other commonly used materials can all be used.

Fine particles smaller than the average particle diameter of the toner, such as silicon dioxide, aluminum oxide, titanium oxide, zinc stearate, and various resin fine powders, can be added to the particle surface of the toner according to the present invention.

Effects of the Invention According to the developer of the present invention, various effects as described below can be achieved based on the fact that the magnetic core material is coated with a specific copolymer and the specific charge control agent is dispersed in the toner. It will be possible.

First, since the rate of increase in charge is high and the amount of charge during running is not reduced, the life of the developer can be extended without causing fogging early and causing in-machine contamination.

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples. However, the present invention is not limited to these examples.

Example 1 10 parts by weight of a polymer having a side chain of N-perfluorooctylsulfonyl-N-propylaminoethyl methacrylate and a main chain of ethyl acrylate (weight ratio 10:90) was dissolved in 200 parts by weight of methyl ethyl ketone. Using a fluidized bed coating device, 1000 parts by weight of spherical ferrite powder having an average particle size of 100 μm was coated with this solution to obtain a carrier according to the present invention.

On the other hand, 90 parts by weight of a polymer composed of 80 parts by weight of styrene and 20 parts by weight of butyl acrylate, 8 parts by weight of carbon black,
2 parts by weight of chromium complex salt of O, O'-dihydroxyazo dye was kneaded in a pressure kneader, cooled, crushed in a hammer mill and then in a jet mill, and further classified to obtain an average particle diameter of 11 μm.
The toner according to the present invention is obtained.

3 parts by weight of this toner and 100 parts by weight of the above carrier were mixed to obtain a developer according to the present invention.

Comparative Example-1 The same two kinds of monomers as in Example-1 were randomly polymerized at the same weight ratio, and a control carrier was obtained by the completely same operation as in Example-1.

A control developer was obtained by mixing 100 parts by weight of this carrier with 3 parts by weight of the toner of Example-1.

Comparative Example-2 A control carrier was obtained in the same manner as in Example-1, except that the fluorinated alkyl methacrylate was used in Example-1 and the amount of ethyl methacrylate was changed to 100 parts.

A control developer was obtained by mixing 100 parts by weight of this carrier with 3 parts by weight of the toner of Example-1.

When these developers were subjected to continuous copying test with Fuji Xerox 4370, the following results were obtained.

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Claims (2)

[Claims] 1. A carrier comprising a core material coated with a fluorinated alkyl acrylate or a fluorinated alkyl methacrylate graft or block copolymer, and a toner having a colorant and a negative charge control agent dispersed in a resin. A developer characterized in that. 2. The developer according to claim 1, wherein the negative charge control agent is a chromium complex salt of an O, O'-dihydroxyazo dye.