JPH0511504A - Magnenta toner for electrophotography - Google Patents

Abstract

PURPOSE:To obtain the magenta toner which satisfies the characteristics required as a color toner with good balance and with which stable images are obtainable. CONSTITUTION:This magenta toner for electrophotography contains at least a binder resin, a quinacridone resin and the rhodamine compd. expressed by formula (I). (In the formula, D denotes a rhodamine dye base material, R denotes 5 to 22C alkyl group; X<1>, X<2>, X<3> and X<4> respectively denote a hydrogen atom or sulfonic group, of which at least two are a sulfone group; m denotes 2 to 4 integer).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color toner for electrophotography, and more particularly to a magenta toner for electrophotography containing a specific compound.

[0002]

BACKGROUND OF THE INVENTION Electrophotography is described in US Pat. No. 2,297,691.
Japanese Patent Publication No. 42-23910 and Japanese Patent Publication No. 43-43
As disclosed in various publications such as JP-A-24748, generally, an electrostatic latent electric latent image is formed on a photoreceptor containing a photoconductive substance by various means, and then the latent image is developed as a powder image with a toner. If necessary, the powder image is transferred onto paper and then fixed by heating, pressurizing or solvent vapor.

Further, in recent years, an electrostatic latent image of an original is formed by exposing it to light that has been spectrally dispersed, and this is developed with color toners of respective colors to obtain colored copy images, or copy images of respective colors are superposed. A color copying method for obtaining a full-color copied image has been put into practical use, and yellow, magenta, cyan, and other color toners in which dyes and / or pigments of respective colors are dispersed in a binder resin have been manufactured as color toners to be used. There is.

As the toner, 1 to 3 are prepared by dispersing a colorant such as a dye or a pigment in a resin such as polyester.
Particles finely pulverized to about 0 μm are used, and such a toner is mixed and used as a carrier substance such as glass beads, iron powder or fur.

[0005]

However, it has been difficult for conventional color toners to satisfy various performances required for color toners. That is, the conventional color toner has the following problems.

(1) Color reproduction becomes difficult when multicolor overprinting is performed due to lack of light transmission, and a good transmission image cannot be obtained when a transparency for an overhead projector (OHP) is produced. (2) Since the spectral reflection characteristics are not sufficient, good hue / color cannot be obtained. (3) Due to lack of fastness to light and heat, the copy image is discolored while being left unattended.

(4) Due to the low compatibility between the dye and pigment and the binder resin, the dye and pigment migrate to the photosensitive member or the like to deteriorate their performance. (5) Since the charging property is not good, the color balance is lost as the number of copies is increased, and defects such as fog and image density change occur on the image. Therefore, as a result of diligent studies to solve such problems, the present inventors have found that an excellent toner that solves the above problems by using a specific compound in combination as a colorant and satisfies various required characteristics in a well-balanced manner. The present invention has been reached by knowing that it can be obtained.

[0008]

That is, the gist of the present invention is to contain at least a binder resin, a quinacridone-based pigment, and a rhodamine-based compound represented by the following general formula (I), and magenta for electrophotography. Exists in toner.

[0009]

[General formula]

(However, D is a rhodamine dye base, R is
Represents an alkyl group having 5 to 22 carbon atoms, and X ¹ , X ² , X ³
And X ⁴ each represent a hydrogen atom or a sulfone group, at least two of which are sulfone groups and m
Represents an integer of 2 to 4. ) Hereinafter, the present invention will be described in detail.

The quinacridone pigment used as a colorant in the magenta toner of the present invention is a combination of an unsubstituted quinacridone pigment having no substituent in the body, a substituted quinacridone pigment having a substituent, and a mixture of those having different substituents. Solid solution quinacridone pigments and the like are known, and any of them can be preferably used. Typical examples of these are as follows.

(1) C.I. I. Pigment Vio
let 19

(2) C.I. I. Pigment Red
122

(3) C.I. I. Pigment Red
209

(4) C.I. I. Pigment Red
206

(5) C.I. I. Pigment Red
207

On the other hand, in the rhodamine compound represented by the general formula (I), D is usually the following general formula (II).

(Wherein R ¹ is R ⁶ -N-R ⁷ (R ⁶ and R
⁷ represents a hydrogen atom, an alkyl group or a substituted or unsubstituted aryl group), a hydroxyl group or an alkoxy group, R ² represents a hydrogen atom or a lower alkyl group,
R ³ , R ⁴ and R ⁵ represent a hydrogen atom, an alkyl group or a substituted or unsubstituted aryl group. Particularly, R ² is preferably a hydrogen atom, and R ³ is preferably a substituted aryl group or a hydrogen atom.

Is a rhodamine dye matrix represented by
R represents an alkyl group having 5 to 22 carbon atoms, and X ¹ , X ² , X
³ and X ⁴ each represent a hydrogen atom or a sulfone group, at least two of which are sulfone groups,
m represents the number of sulfone groups among X ¹ , X ² , X ³ and X ⁴ . That is, the compound of the general formula (I) used in the magenta toner of the present invention is
The rhodamine dye matrix represented by I) is reacted with alkylated diphenyl ether sulfonic acid which is an anionic surfactant to form an ionic bond, and it may have a good balance of polarities. Excellent in stability and compatibility with resin. Typical examples of the compound represented by formula (I) are shown below.

[0020]

[0021]

[0022]

[0023]

[0024]

In the magenta toner of the present invention, by using the above-mentioned quinacridone pigment and a specific rhodamine compound as a colorant, various required characteristics as a color toner, in particular, spectral reflection characteristics, charging characteristics and light resistance are obtained. A toner having excellent properties is obtained.

The colorant to be contained in the magenta toner of the present invention is not limited to the compounds of the specific examples listed above, and two or more kinds of quinacridone pigments and rhodamine compounds are mixed and used. It is also possible. Further, a compound other than these two kinds of compounds may be used in combination as a colorant as long as the preferable effect produced by the combination of the quinacridone pigment and the rhodamine compound is not impaired.

On the other hand, the binder resin for the magenta toner of the present invention can be selected from a wide range including known ones, but colorless and transparent ones are preferable, and examples thereof include polystyrene, chloropolystyrene and poly-α-methylstyrene. , Styrene-chlorostyrene copolymer, styrene-propylene copolymer, styrene-budadiene copolymer, styrene-vinyl chloride copolymer, styrene-vinyl acetate copolymer, styrene-maleic acid copolymer, styrene-acryl Acid ester copolymer (styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, and styrene-phenyl acrylate copolymer ), Styrene-methacrylic acid ester copolymerization (Styrene - methyl methacrylate copolymer, styrene - ethyl methacrylate copolymer,
Styrene-butyl methacrylate copolymer, styrene-octyl methacrylate copolymer, styrene-phenyl methacrylate copolymer, etc.), styrene-α-chloromethyl acrylate copolymer and styrene-acrylonyl-acrylate copolymer Styrene-based resins such as polymers (styrene or styrene-substituted homopolymers or copolymers), vinyl chloride resins, rosin-modified maleic acid resins, phenol resins, epoxy resins, saturated or unsaturated polyester resins, low molecular weight polyethylene, Low molecular weight polypropylene, ionomer resin, polyurethane resin, sill cone resin, ketone resin, ethylene-ethyl acrylate copolymer, xylene resin and polyvinyl butyral resin, etc., but as particularly preferable resin for use in the present invention, Styrene-based resins, such as saturated or unsaturated polyester resins and epoxy resins. Further, the above resins are not limited to being used alone, but may be used in combination of two or more kinds.

The total amount of the colorant added to the toner in the previous period is preferably 0.1 to 30 parts by weight, more preferably 1 to 10 parts by weight, based on 100 parts by weight of the binder resin. If the amount added is too small, the coloring effect as magenta will be poor, and if the amount added is too large, the fixability of the toner will be adversely affected. The ratio of the amount of the quinacridone-based pigment to the rhodamine-based compound represented by the general formula (I) added is properly determined depending on the required hue and charge amount, but is usually 1: 4 to. 4: 1 is preferred.

The charge control of the toner may be performed by the binder resin or the dye / pigment itself, but if necessary, a colorless or light-colored charge control agent which does not cause a problem in color reproduction may be added. Of these, a basic / electron-donating substance such as a quaternary ammonium salt is appropriately selected for positive charging, and an acidic or electron-withdrawing substance such as a metal chelate or a metal-containing dye is appropriately selected for negative charging. It is good to use it. The addition amount of the charge control agent may be determined in consideration of the charging property of the binder resin, the manufacturing method including the addition amount / dispersion method of the colorant, and the charging property of other additives. On the other hand, 0.1 to 10 parts by weight is suitable.
These charge control agents may be used by being mixed and added to the binder resin, or may be used by being attached to the surface of the toner particles by various means.

In addition, to the toner of the present invention, a solid electrolyte, a polymer electrolyte, a charge transfer complex, a conductor such as a metal oxide such as tin oxide, a semiconductor, a ferroelectric substance, a magnetic substance or the like is added. The electrical properties of the toner can be controlled. Further, it is possible to add various plasticizers, releasing agents and other auxiliaries to the toner for the purpose of adjusting thermal characteristics and physical characteristics. Appropriate addition amount is 0.1 to 10 parts by weight.

Further, the toner particles have TiO ₂ , Al ₂ O.
It is possible to improve the fluidity and aggregation resistance of the toner by adding fine powders such as ₃ , SiO ₂ and covering the surface of the toner particles with these powders. The addition amount is preferably 0.1 to 5 parts by weight with respect to 100 parts by weight of the toner particles.

Various conventionally used methods can be applied to the method for producing the toner of the present invention. For example, the following examples can be given as general production methods.

First, a resin and a colorant (additives such as a charge control agent may be added depending on the case) are ball-milled.
Disperse evenly with a V-type mixer or Henschel mixer. The dispersion is then pressure kneaded, extruder,
Melt and knead with a roll mill. The kneaded product is crushed by a crusher such as a hammer mill or a jet mill, and the obtained powder is classified by an air classifier, a dispersion classifier or the like. Further, for the purpose of improving the dispersibility of the pigment and the like, a step of premixing the pigment with the binder resin by a masterbatch method or the like may be provided.

The obtained color toner can be mixed with a carrier and used as a developer for copying by electrophotography. The carrier is a known magnetic substance such as iron powder type carrier, ferrite type carrier or the like, or a carrier whose surface is coated with 10 to 10 parts by weight of the toner.
It is preferable to use 0 part by weight.

[0035]

EXAMPLES The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded. In addition, in each of the examples and the comparative examples, “part” means “part by weight”.

Example 1 Unsaturated polyester resin 100 parts Quinacridone pigment 2 parts (CI Pigment Violent 19) Rhodamine compound (1) 2 parts Chromic salicylate complex compound 2 parts

The above materials are melt-kneaded with a hot roll mill,
After cooling, coarse pulverization was performed using a hammer mill, and then fine pulverization was performed using an air jet type fine pulverizer. The resulting fine powder was classified to select particles having a particle size of 5 to 25 μm to obtain a magenta toner. To 100 parts of this magenta toner, 6 parts were added and mixed by a V-type mixer to obtain a developer.

When this developer was used for actual copying on a dry plain paper electrophotographic copying machine, there was no fog, the spectral reflection characteristics were good, and a clear image was obtained. Further, 20,000 copies were continuously copied using this developer, but there was almost no change in image density or other deterioration in image quality. Further, the charge amount of the developer was stable with little change.

(Example 2) Except that the unsaturated polyester resin was replaced with a styrene-n-butyl acrylate copolymer, the same procedure as in Example 1 was carried out, and almost the same results as in Example 1 were obtained. ..

(Example 3) P as a quinacridone pigment
Pigment instead of igment Violet 19
Except that ent Red 122 was used, the same procedure as in Example 1 was carried out, and almost the same results as in Example 1 were obtained.

(Example 4) Epoxy resin 100 parts Quinacridone pigment 1 part (CI Pigment Red 209) Rhodamine compound (3) 3 parts Zinc salicylate complex compound 2 parts

The toner and the developer were prepared and evaluated in exactly the same manner as in Example 1 except that the above formulation was used. As a result, almost the same results as in Example 1 were obtained.

[0043]

The magenta toner for electrophotography of the present invention is
The properties required as a color toner are satisfied in a well-balanced manner, and among them, the spectral reflection property is excellent and the charging property is good, and a stable image is always obtained.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hirofumi Oda Inventor Hirofumi Oda 370 Enzo, Chigasaki City, Kanagawa Mitsubishi Kasei Co., Ltd. Chigasaki Plant

Claims (1)

1. A magenta toner for electrophotography comprising at least a binder resin, a quinacridone pigment and a rhodamine compound represented by the following general formula (I). [General formula] (In the formula, D is a rhodamine-based dye base and R is a carbon number of 5 to 2
2 represents an alkyl group, and X ¹ , X ² , X ³ and X ⁴ each represent a hydrogen atom or a sulfone group, at least two of which are sulfone groups and m represents an integer of 2 to 4. )