JPH02264965A - Electrophotographic color toner - Google Patents

Abstract

PURPOSE:To enhance lightfastness of a color toner and to stabilize an image by incorporating a specified compound. CONSTITUTION:The color toner contains the binder resin, such as polyester, a colorant, and the compound represented by formula I in which each of R<1> and R<2> is H or lower alkyl. As the compound of formula I, the compound of formula II and the like can be used and a desired electrostatic charge controller can be added to the toner, and auxiliary agents, such as a plasticizer and a releasing agent, can be added.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a color toner for electrophotography, and more particularly to a color toner for electrophotography containing a specific compound.

(Prior art) The electrophotographic method is described in U.S. Patent No. 2.297A9/
Publication No. 12-23910 and Special Publication No. 11.7-2'1
As disclosed in various publications such as No. 7'1g, in general, an electrical latent image of electrostatic charge is formed on a photoreceptor containing a photoconductive material by various means, and then the #latent image is converted into a powder image with toner. After developing and transferring the powder image as necessary, it is fixed by heating, pressure, solvent vapor, or the like.

In addition, in recent years, the electrostatic latent image of the document is formed by exposing it to spectral light, and this is developed with color toner of each color to obtain a colored copy image, or the copy images of each color are superimposed to form a full-color copy image. A color copying method for obtaining a copied image has been put into practical use, and color toners such as yellow, magenta, and cyan, which are made by dispersing dyes and/or pigments of various colors in a binder resin, have been produced.

The toner used is particles made by dispersing coloring agents such as dyes and pigments in a resin such as polyester and finely pulverized to about 3θμm.Such toners are made of glass beads, iron powder or fur. It is used by mixing with a carrier material such as.

(Problems to be Solved by the Invention) However, in conventional color toners, the dyes and pigments used as colorants do not have sufficient light resistance, and if the copy sample is left undisturbed, the color may change, and each color Problems such as a decrease in color reproducibility have arisen due to changes in color balance due to discoloration of the toner.

(Means for Solving the Problems) As a result of intensive studies to solve these problems, the present inventors have obtained an excellent toner that solves the above problems by incorporating a compound having a specific structure. The present invention was achieved by learning that

That is, the gist of the present invention resides in an electrophotographic toner characterized by containing a binder resin, a colorant, and a compound represented by the following formula (CI).

(In the formula, R1 and R2 each represent a hydrogen atom or a lower alkyl group.) (Function) The present invention will be explained in detail below.

The binder resin for toner can be selected from a wide range including known ones, but colorless and transparent ones are preferable, such as polystyrene, chloropolystyrene,
Poly-α-methylstyrene, styrene-chlorostyrene copolymer, styrene-propylene copolymer, styrene-
butadiene copolymer, styrene-vinyl chloride copolymer,
Styrene-vinyl acetate copolymer, styrene-maleic acid copolymer, styrene-acrylic ester copolymer (styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer) styrene-octyl acrylate copolymer, styrene-phenyl acrylate copolymer, etc.), styrene-
Methacrylic acid ester copolymers (styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-phenyl methacrylate copolymer, etc.), styrene-α-chlor Styrenic resins (unipolymers or copolymers containing styrene or styrene substitutes) such as methyl acrylate copolymer and styrene-acrylonitrile-acrylic ester copolymer, vinyl chloride resin, rosin-modified maleic acid resin, phenol resins, epoxy resins, saturated or unsaturated polyester resins, low molecular weight polyethylene, low molecular weight polypropylene, ionomer resins, polyurethane resins, silicone resins, ketone resins, ethylene-ethyl acrylate copolymers, xylene resins, and polyvinyl butyral resins. Particularly preferred resins for use in the present invention include styrene resins, saturated or unsaturated polyester resins, and epoxy resins. Moreover, the above resins are not limited to being used alone, but can also be used in combination of two or more.

Furthermore, as a coloring agent, any known dye or pigment used in color toners can be used without any particular restriction, and it goes without saying that the above coloring agents can be used not only alone, but also in combination. .

The amount of the colorant added to the toner is preferably 0.1 to 30 parts by weight based on 10θ parts by weight of the binder resin, particularly O,
S to 10 parts by weight is desirable. If the amount added is too small, the coloring effect will be poor, and if it is too large, the fixing properties will be poor, which is an undesirable tendency.

The charge control of the toner may be performed using the binder resin or dye/pigment itself, but if necessary, a charge control agent that does not cause problems in color reproduction may be used in combination. As the positive chargeability control agent, a basic/electron-donating substance such as a class ammonium salt may be used, and as the negative chargeability control agent, an acidic/electron-withdrawing substance such as metal chelates or alloy dyes may be appropriately selected and used. good.

The amount of the charge control agent to be added should be determined after considering conditions such as the chargeability of the binder resin, the manufacturing method including the amount and dispersion method of the colorant, and the chargeability of other additives. On the other hand, 7 to 10 parts by weight of θ is appropriate.

In addition, inorganic particles such as metal oxides or inorganic substances surface-treated with the above-mentioned organic substances may be used.

These charge control agents may be used by being mixed into the binder resin, or may be used in the form of being attached to the surface of the toner particles.

Furthermore, the electrical properties of the toner can be controlled by adding solid electrolytes, polymer electrolytes, charge transfer complexes, conductors such as metal oxides such as tin oxide, semiconductors, ferroelectric materials, magnetic materials, etc. 0 In addition, it is also possible to add various auxiliary agents such as plasticizers and release agents to the toner for the purpose of adjusting thermal properties, physical properties, etc. The amount added is suitably 0.1 to 70 parts by weight.

Furthermore, toner particles include TiO□, A1201, and SiO□.
The fluidity and agglomeration resistance of the toner can be improved by adding fine powders such as these and coating the surfaces of the toner particles. The amount added is preferably 0.7 to 70 parts by weight per 700 parts by weight of toner particles.

Various conventional toner manufacturing methods can be applied to the toner manufacturing method of the present invention. For example, the following example can be given as a boat fishing manufacturing method.

First, the resin and colorant (additives such as a charge control agent may be added depending on the case) are mixed in a ball mill, a ■ type mixer,
Uniformly disperse using an S-type mixer, Henschel mixer, etc.

Next, the dispersion is melt-kneaded using a double-arm kneader, a pressure kneader, an extruder roll mill, or the like. The kneaded material is pulverized using a pulverizer such as a nozzle mill, cutter mill, jet mill, or ball mill, and the resulting powder is further classified using an air classifier or the like.

The resulting color toner can be mixed with a carrier and used as a developer for electrophotographic copying. As the carrier, it is preferable to use a magnetic material such as a known iron powder carrier or ferrite carrier, or a carrier coated on the surface thereof in an amount of IO parts to 10 θ parts per part of toner.

In the compound of general formula (1) contained in the color toner for electrophotography of the present invention, a+ and R2 each represent a hydrogen atom or a lower alkyl group such as a methyl group, an ethyl group, or a tertiary-butyl group. Preferred specific examples of the compounds are as follows, but among the compounds, the compounds that can be used in the present invention are not limited to these. The above may be used in combination.

By incorporating the compound represented by the general formula (1) into the power 2-toner of each color such as yellow, magenta, and cyan, the light resistance of the color toner is significantly improved.

The amount of the compound added is preferably 0.07 to 20 parts by weight, particularly preferably 0.7 to 3 parts by weight, per 100 parts by weight of the binder resin.

(Examples) The present invention will be explained in more detail by Examples below, but the present invention is not limited by the Examples unless it exceeds the gist thereof. Note that in each of the Examples and Comparative Examples, "parts" simply represent "parts by weight."

(Example/) 100 parts of saturated polyester resin Compound 7
Part 3 C, L Pigment Red gi
Part k: Zinc salicylate complex compound 1 part The above materials were melt-kneaded in a hot roll mill, cooled, and then coarsely ground using a hammer mill, and then finely ground using an air jet type pulverizer.

The obtained fine powder was classified to select particles having a particle size of 5 to 25 μm to obtain a color toner. This color toner is 10% iron powder.
A developer was prepared by adding 6 parts to the θ part and mixing with a ■ type mixer.

Using this developer, a document copied using a dry-type plain paper electrophotographic copying machine was measured using a carbon arc fade meter (carbon arc auto fade meter manufactured by Suga Test Instruments Co., Ltd.).
When the color difference was measured after exposure for a period of time, ΔE'ab = /, g0, and there was little change in color.

(Comparative Example 1) When the same procedure as in Example 1 was carried out except that the above-mentioned compound 1 was not used as a material, ΔE'ab = 7.9 g, and the color change was remarkable.

(Example 1) The same procedure as Example 1 was made except that Pigment Yellow /2 was used for C, 1, and Pigment Red / Pigment Yellow /2 as the material. There were few changes.

(Comparative Example 3) The same procedure as Example 1 was carried out except that the compound 1 was not used as a material. △Elab = , ? , 7 g, and the color change was remarkable.

(Example J) When the same procedure as in Example 1 was used except that the compound 1 was used instead of the compound 2 as a material, there was little change in color between ΔE°ab = /, i, and t.

(Example D) The same procedure as in Example 1 was carried out except that the compound 3 was used instead of the compound / as the material. ΔE°ab = /,! ;! ; There was little change in color.

(Effects of the Invention) The color toner for electrophotography of the present invention has particularly excellent light resistance,
It always gives stable and good images.

Applicant: Mitsubishi Kasei Corporation Representative Patent Attorney Naga Kagawa Other r names

Claims (1)

[Claims] (1) Binder resin, colorant and the following general formula (I
) A color toner for electrophotography, characterized by containing a compound represented by: ▲There are mathematical formulas, chemical formulas, tables, etc.▼・・・・・・・・・(
I) (In the formula, R^1 and R^2 each represent a hydrogen atom or a lower alkyl group.)