JPH0816806B2 - Color toner for electrophotography - Google Patents

Description

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

(Prior Art) In recent years, an electrostatic latent image of an original is formed by exposing it to light that has been dispersed, and then developed with color toner of each color to obtain a colored copy image, or a copy image of each color is overlaid. A color copying method for obtaining a full-color copied image has been put into practical use, and yellow, magenta, cyan, etc. color toners made by dispersing dyes and / or pigments of respective colors in a binder resin are manufactured as color toners used for the method. Has been done.

(Problems to be Solved by the Invention) However, conventional color toners have not always sufficiently satisfied various performances required for color toners.

In other words, with conventional color toners: ・ Because of lack of light transmission, color reproduction becomes difficult when multicolor overprinting is performed, and when transmitting transparency for overhead projector (OHP), a good transmission image is obtained. Can't get

・ Because of the poor spectral reflection characteristics, good hue and color cannot be obtained.

・ Due to lack of fastness to light and heat, the copy image fades while left unattended.

・ Due to the low affinity between the dye and pigment and the binder resin, the dye and pigment migrate to the photoconductor and the like, which deteriorates the performance.

Since the charging characteristics are not good, the color balance is lost as the number of copies is increased, and defects such as a change in fog density occur on the image.

There were problems such as.

As a result of intensive studies to solve the above problems, the present inventors have found that an excellent toner having the above problems solved can be obtained by using a colorant having a specific structure. Reached

(Means for Solving the Problems) That is, the gist of the present invention is to provide a rhodamine compound represented by the general formula (I) as the colorant in an electrophotographic color toner containing a colorant and a binder resin. The present invention resides in a color toner for electrophotography, which is characterized by containing the above.

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

As the binder resin for toner, it is possible to widely use including known ones, but colorless and transparent ones are preferable, for example, 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 acid ester copolymer (for example, 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 copolymer (for example, styrene-
Methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-phenyl methacrylate copolymer, etc.),
Styrene-α-chloromethyl acrylate copolymers and styrene-acrylonitrile-acrylic acid ester copolymers and other styrene resins (styrene and / or styrene-substituted homopolymers or copolymers), vinyl chloride resin,
Styrene-vinyl acetate copolymer, rosin-modified maleic acid resin, phenol resin, epoxy resin, polyester resin, low molecular weight polyethylene, low molecular weight polypropylene,
There are ionomer resins, polyurethane resins, silicone resins, ketone resins, ethylene-ethyl acrylate copolymers, xylene resins, polyvinyl butyral resins, etc., but as the resins particularly preferred in the practice of the present invention, styrene resins, polyester resins, silicone resins And epoxy resin. Further, the above resins are not limited to being used alone, but may be used in combination of two or more kinds.

In the compound represented by the general formula (I) used as a colorant in the present invention, D is a rhodamine-based dye base,
Preferably the following general formula (II) (Where R ¹ is (R ⁶ and R ⁷ each represent 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, and R ³ , R ⁴ and Each R ⁵ represents a hydrogen atom, an alkyl group or a substituted or unsubstituted aryl group. ] It represents the rhodamine type dye matrix represented by. The preferred specific examples of the rhodamine compounds are as follows.

The present invention is not limited to the compounds of the above specific examples, and it is also possible to use a mixture of two or more of them.

Further, the compound represented by the general formula (I) can be used as a main component of the colorant of the magenta toner, but in the case of a toner of another color, the compound represented by the general formula (I) is improved in color. It is also possible to add it for.

In addition, the amount of colorant added to the toner is the binder resin.
0.1 to 30 parts by weight per 100 parts by weight is desirable, especially 0.5
~ 10 parts by weight is desirable. If the addition amount is too small, the coloring effect as magenta will be poor, and if it is too large, the fixability will be inferior, which is not preferable.

The charge control of the toner may be performed by the binder resin and the dye / pigment itself, but if necessary, a charge control agent that does not cause a problem in color reproduction may be used together. Positive charge control agents include quaternary ammonium salts, basic / electron-donating organic substances, negative charge control agents include metal chelates,
A metal-containing dye, an acidic or electron-withdrawing organic substance, or the like can be used.

The addition amount of the charge control agent can be determined in consideration of the chargeability of the binder resin, the manufacturing method including the addition amount / dispersion method of the colorant, and the chargeability of other additives. 0.1 to 10 parts by weight is suitable.

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

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

Furthermore, solid electrolytes, polymer electrolytes, charge transfer complexes, conductors such as metal oxides such as tin oxide, semiconductors and / or
Alternatively, the electrical properties of the toner can be controlled by adding a ferroelectric substance, a magnetic substance, or the like.

In addition, auxiliary agents such as various plasticizers and release agents may be added to the toner for the purpose of adjusting thermal characteristics and physical characteristics. The appropriate amount of addition is 0.1 to 10 parts by weight.

Furthermore, for the toner particles, TiO ₂ , Al ₂ O ₃ , SiO ₂
It is possible to improve the fluidity and aggregation resistance of the toner by adding fine powder such as the above and coating the surface of the toner particle with them. The addition amount is preferably 0.1 to 10 parts by weight.

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

First, a resin and a colorant (such as a charge control agent in some cases) are uniformly dispersed with a ball mill, a V-type mixer, an S-type mixer, a Henschel mixer, or the like. The dispersion is then double-armed kneader,
Melt and knead with a pressure kneader. The mixture is crushed by a crusher such as a hammer mill, a jet mill or a ball mill, and the obtained powder is classified by an air classifier or the like.

The obtained color toner can be mixed with a carrier to form a developer for electrophotography, and can be used for copying by a conventionally practiced electrophotographic method. As the carrier, it is preferable to use 10 to 100 parts of a magnetic substance such as a known iron powder-based or ferrite-based carrier or a material coated on the surface thereof with respect to 1 part of the toner.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples as long as the gist thereof is not exceeded. In addition, "part" in an Example represents a "weight part."

(Example 1) 100 parts of unsaturated polyester resin Compound 3 parts 3 parts of zinc salicylate complex compound 2 parts were melt-kneaded in a hot roll mill, cooled, coarsely pulverized using a hammer mill, and then finely pulverized by an air jet system. Finely ground. Particle size 5-25
Particles of μm were selected and used as a toner. This toner is iron powder 10
6 parts was added to 0 parts and mixed with a V-type mixer to obtain a developer.

When this developer was used to make a copy 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, using this developer, 20,000 sheets were continuously copied, but the quality of the copied image was not deteriorated. The image densities after initial copying and after copying 20,000 sheets are 1.52 and 1.49, respectively, and the charge amounts of this toner are -14.7 μc / g and -15.1 μc / g at the beginning of copying and after copying 20,000 sheets, respectively. , The charge amount was stable.

(Example 2) Except that a styrene-n-butyl acrylate copolymer was used instead of the unsaturated polyester resin, the same procedure as in Example 1 was carried out, and a clear image was obtained with good spectral reflection characteristics. .

(Example 3) The same operation as in Example 1 was carried out except that the compound (b) was used instead of the compound (b) as a colorant, and a clear image having good spectral reflection characteristics was obtained.

(Example 4) The same operation as in Example 1 was carried out except that the compound (c) was used instead of the compound (b) as a colorant, and a clear image having good spectral reflection characteristics was obtained.

(Example 5) The same operation as in Example 1 was carried out except that the compound (d) was used instead of the compound (b) as a colorant, and a clear image having good spectral reflection characteristics was obtained.

(Effects of the Invention) As described above, the color toner of the present invention has excellent spectral reflection characteristics, good charging characteristics, and stably gives a clear image.

Claims (1)

[Claims] 1. A color toner for electrophotography, comprising a colorant and a binder resin, wherein the colorant comprises a rhodamine compound represented by the general formula (I). . (In the formula, D represents a rhodamine-based dye base, and m is 2 to 4
Represents an integer, and R represents an alkyl group having 5 to 22 carbon atoms. X ₁ , X ₂ , X ₃ and X ₄ each represent hydrogen or a sulfone group, and at least two of X ₁ , X ₂ , X ₃ and X ₄ are sulfone groups. )