JPH03163566A - Electrophotographic magenta toner - Google Patents

Abstract

PURPOSE:To obtain excellent hue and color by incorporating a colorant, binder resin and fluorescent whitening agent into the magenta toner. CONSTITUTION:A colorant, binder resin and fluorescent whitening agent are incorporated into the magenta toner. The whitening agent ordinarily absorbs UV and emits purple-blue light, and a diaminostilbenzylsulfonic acid derivative and an imidazole derivative, etc., are exemplified. From 0.1 to 30pts.wt. of the agent is added to the toner. A colorless transparent binder resin is preferably used, polystyrene, polychlorostyrene, poly-alpha-methylstyrene, etc., are exemplified, and 0.1-30pts.wt. of the colorant is preferably added to the toner based on 100pts. wt. of the toner resin. A picture excellent in hue and color is obtained in this way by adding the fluorescent whitening agent.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a magenta toner for electrophotography. (Prior art) The electrophotographic method is described in U.S. Patent No. 2297691,
As disclosed in various publications such as Japanese Patent Publication No. 23910 and Japanese Patent Publication No. 43-24748, generally an electrical latent image of electrostatic charges is formed on a photoreceptor containing a photoconductive material by various means, and then the electrostatic latent image is formed. The latent image is developed as a powder image with toner, and the powder image is transferred to paper or the like as required, and then fixed by heating, pressure, solvent vapor, or the like.

In addition, in recent years, the electrostatic latent image of a document is made visible 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. A color copying method for obtaining full-color copied images 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 manufactured. .

The toner used is particles made by dispersing coloring agents such as dyes and pigments in resin such as polyester, and finely pulverizing the particles to about 1 to 30 μm. It is used by mixing with a carrier material such as.

(Problems to be Solved by the Invention) However, it has been difficult for conventional color toners to satisfy various performances required of color toners.

That is, in conventional color toner, (1)
Due to the lack of light transparency, color reproduction becomes difficult when overprinting multiple colors, and overhead projects (OH
When creating transparency for P), a good transparent image cannot be obtained.

(2) Good hue and color cannot be obtained because the spectral reflection characteristics are not good.

(3) Due to insufficient fastness to light and heat, the color of the copied image fades during storage.

(4) Due to the low affinity between dyes and pigments and binder resin,
The dyes and pigments migrate to the photoreceptor, reducing its performance.

(5) Due to poor charging characteristics, the color balance deteriorates as the number of copies increases, and defects such as fogging and density changes occur on images.

Problems such as these tend to occur, and a combination of resin and colorant that satisfies all of these required properties has not yet been found. In particular, in the case of magenta toner, even if a combination that satisfies all other required properties is obtained, the spectral reflectance in the vicinity of 400 to 450 nm is insufficient, and good hue and color cannot be obtained, and color overlap occurs. There was a problem with the color becoming dull when it was used.

(Means for Solving the Problems) Therefore, as a result of intensive studies to solve these problems, the present inventors found that an excellent toner in which the above problems were solved by using a fluorescent whitening agent was obtained. After learning this, we arrived at the present invention.

That is, the gist of the present invention resides in a magenta toner for electrophotography containing a colorant, a binder resin, and a fluorescent whitening agent.

(Function) The optical brightener used in the present invention is generally a material that absorbs ultraviolet rays and emits violet-blue light, and includes diξnostilbenzyl sulfonic acid derivatives, imidazole derivatives, coumarin derivatives, triazole derivatives, carbazole derivatives,
Examples include pyridine derivatives, naphthalic acid derivatives, imidazolone derivatives, etc. Specifically, for example, I3ayer
Product name made by AG: Blankophor EBM 1 iq
, , Blankophor ER liq. , manufactured by Hamamoto Dye■Product name: Everwhite ERN c
onc,,Everwhite Fluoltte
XMF (ICI>, manufactured by Showa Kagaku Kogyo ■Product name: Hakk
o1 8542-2, Hakkol STR. ．． H
akko l STR-NW, Hakko IS
TB, Hoechst AG product name Hostalu
x P.E. ．． HoSta lux EBUs }I
os ta luxERU, has ta lux
SE, Hosta lux JP104, l{os
talux ERC%
RF% Hasta lux ETR, Host
a lux ENU, manufactured by Showa Kako ■Product name: Jllum
inarl SRN conc. I11umina
rl ER conc. Illuminarl
PS, Illuminarl PBFconc.
Illuminarl SGN canc. , I
1 1uminarl EP-100,I11um
inarl EP-400, Illuminarl
SBF h/c, Sandoz Ltd. Product name: Leucophor EFN% Leucophor
r EF2N% Leucophor E28K, Le
ucophor E3BKXLeucophor
EHB+. Leucophor ET, manufactured by Mitsubishi Corporation, product name MikawhiteKTN conc. , Mi
kawhite KTNh/c, Mi kaWh i
t e KTN u/c, Mikawhite
MTN conc, manufactured by Mitsui Toatsu Chemical ■Product name: Mi
'}Jephor ERN conc. , Mike
phor ETN conc. , @ Nippon Chemical Industry Co., Ltd. Product name: NikkabrightFEN con
c, , Nikkabright FEN h/c
, Nikkabright BN cone, ,
Nikkabr light BN h/c, Nik
kabright F2B conc. , Nik
kabright F2B h/c, Nikkab
right 8720 V-01, Nikkabr
light 8720 V-01 h/c, Nik
kabright Palanil Brill.
Why ite R (BASF), BASF
Product name: Ultraphor BN, Ultra made by AG
phor RN, Ultraphor SBL, U
ltraphor SFG, Ultraphor
SFR, Ultraphor VL, Ciba-Ge
igy Ltd. Product name: TJvitex EBF
%Uvitex ERN% Uvitex ER
T, Uvitex EHFS Uvitex
EMTS UVitexEMV and product name Whitex ERN cone manufactured by Sumitomo Chemical Co., Ltd., raw materials for fluorescent whitening dyes for textiles, and Ciba-Geigy L
td. Product name: Uvitex OB, Sumitomo Chemical Co., Ltd.
Product name: Whitef tour BsWhitef
lour PSN c. c. , Whiteflow
r HCS, Why it's our
PHRc. c, and Whitef Iour PC3
Fluorescent brighteners for resins such as the following can be suitably used. The amount of optical brightener added to the toner is O. 1 to 30 parts by weight is preferred, particularly 0. 1 to 5 parts by weight is desirable.

A wide range of binder resins for toners can be used, including known ones, but colorless and transparent ones are preferred, such as polystyrene, chlorobolystyrene, poly-α-methylstyrene, styrene-to-styrene copolymer, and 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) Polymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer,
Styrene-octyl acrylate copolymer, styrene-phenyl acrylate copolymer, etc.), styrene-methacrylate copolymer (styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-methacrylate copolymer, etc.) styrene-based resins (styrene or styrene-substituted ester copolymers, such as styrene-alpha-methyl chloroacrylate copolymer, styrene-α-methyl chloroacrylate copolymer, styrene-acrylonitrile-acrylate copolymer, etc.) Containing 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, ionomer resin, polyurethane resin, silicone There are resins, ketone resins, ethylene-ethyl acrylate copolymers, xylene resins, polyvinyl butyral resins, etc., and particularly preferred resins for carrying out the present invention include styrene resins, polyester resins, epoxy resins, etc. . Moreover, the above resins are not limited to being used alone, but can also be used in combination of two or more.

In addition, as the coloring agent, azo compounds, quinacridone compounds, rhodamine compounds, anthraquinone compounds, etc. can be used in known magenta dyes and pigments without particular restrictions, and the above coloring agents are limited to being used alone. Needless to say, two or more types can be used together.

The amount of the colorant added to the toner is 0.00 parts by weight of the binder resin. 1 to 30 parts by weight is desirable, especially 0.
5 to 10 parts by weight is desirable. If the amount added is too small, the coloring effect as a magenta color 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 a positive charge control agent, basic/electron-donating substances such as quaternary ammonium salts,
As the negative chargeability control agent, an acidic or electron-withdrawing substance such as a metal chelate M or a metal-containing dye can be used.

The amount of the charge control agent added can be determined by 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. 0.0% per 100 parts by weight. 1-10
Parts by weight are appropriate.

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 a solid electrolyte, a polymer electrolyte, a charge transfer complex, a metal oxide conductor such as tin oxide, a semiconductor, a ferroelectric material, a magnetic material, or the like.

In addition, it is also possible to add various auxiliary agents such as plasticizers and mold release agents to the toner for the purpose of adjusting thermal properties, physical properties, etc. The amount added is 0.00 parts by weight per 100 parts by weight of the binder resin. 1 to 10 parts by weight is suitable.

Furthermore, for the toner particles, TiO2, A'! 03
By adding fine powders such as , SiOz, etc. and coating the surfaces of toner particles, it is possible to improve the fluidity and agglomeration resistance of the toner. The amount added is 0.00 parts by weight per 100 parts by weight of the binder resin. 1 to 10 parts by weight is preferred.

Various conventional toner manufacturing methods can be applied to the toner manufacturing method of the present invention, and examples of general manufacturing methods include the following.

First, a resin and a coloring agent (if necessary, a charge control agent, etc.) are uniformly dispersed using a pole mill, a V-type mixer, an S-type mixer, a Henschel ξ Kisser, or the like. Next, the dispersion is melt-kneaded using a double-arm kneader, a pressurized kneader, or the like.

The El mixture is pulverized using a pulverizer such as a hammer mill, a jet mill, or a ball mill, and the resulting body is further classified using an air classifier or the like.

The obtained color toner is mixed with a carrier to form an electrophotographic developer, which can be used for copying by the conventional electrophotographic method. As the carrier, it is preferable to use a magnetic material such as a known iron powder carrier or a ferrite carrier, or a carrier coated on the surface thereof in an amount of IO to 100 parts by weight per 1 part by weight of the toner.

(Examples) Specific examples of the present invention will be described below, but the present invention is not limited to these examples. In addition, "parts" in the examples represent "parts by weight."

Example 1 Saturated polyester resin 100 parts (condensate of bisphenol A ethylene oxide adduct and terephric acid) Optical brightener 0. Part 5 (C
iba-Geigy Ltd. Product name υvHex OB) Charge control agent 1 part (chromium alkylsalicylate complex) Magenta colorant 5 parts (C.
I. Pigment Red 122) The above materials were melt-kneaded using 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 is classified to have a particle size of 5 to 2.
Particles of 5 μm were selected to obtain magenta toner. 6 parts of this toner was added to 100 parts of iron powder and mixed in a V-type mixer to prepare a developer.

Comparative Example 1 A developer was obtained in the same manner as in Example 1 except that no fluorescent brightener was added.

Example 2 A developer was obtained in the same manner as in Example 1 except that a styrene-n-butyl acrylate copolymer was used instead of the saturated polyester resin.

Example 3 C.I. as a coloring agent. I. Pigment Red122
Instead, anthraquinone dyes and C, I. Solve
nt Re. A developer was obtained in the same manner as in Example 1 except that d52 was used.

Comparative Example 2 A developer was obtained in the same manner as in Example 3 except that no fluorescent brightener was added.

Example 4 A developer was obtained in the same manner as in Example 3 except that styrene-n-butyl acrylate copolymer was used instead of the saturated polyester resin.

MikawhiteMTN instead of itex OB
A developer was obtained in the same manner as in Example 1, except that the raw material of conc (manufactured by Mitsubishi Chemical Corporation) was used.

Example 6 A developer was obtained in the same manner as in Example 5 except that styrene-n-butyl acrylate copolymer was used instead of the saturated polyester resin.

Using the developers of Examples 1 to 6 and Comparative Examples 1 to 2, development was performed using a dry plain paper electrophotographic copying machine, and the resulting images were R
ed (600-650nm), Green (50
0-550nm), Blue (400-450nm)
) When the image density was measured through each filter, the results shown in Table 1 below were obtained.

The developing bias of the copying machine was adjusted so that the image density was 1.40 when measured through a green filter.

Table 1 As is clear from the above results, the addition of the fluorescent whitening agent reduces the image density measured through the Blue filter.

This is the result of improved spectral reflectance in the 400-450 nm range, and by adding a fluorescent brightener, 400-450 nm
An image with high spectral reflectance at 50 nm and good hue and saturation was obtained.

Furthermore, when 20,000 copies were continuously made using these developers, there was no deterioration in the quality of the copied images, and the toner charge amount was stable throughout. (Effects of the Invention) As explained above, the magenta toner of the present invention has a 400-
Good hue and saturation with high 450nm spectral reflectance,
In addition, the charging characteristics are good, and stable images can always be obtained.

Claims (1)

[Claims] (1) A magenta toner for electrophotography containing a colorant, a binder resin, and a fluorescent whitening agent.