JPS5872948A - Colorant for electrophotographic developer - Google Patents

Abstract

PURPOSE:To obtain a superior colorant for a wet or dry developer by mixing a specified resin and a vinyl chloride polymer having a specified polymn. degree with a specified percentage of a plasticizer basing on the total amount of the resins, a stabilizer, and a pigment or a dye added to a specific percentage of wax. CONSTITUTION:A mixture consisting of a resin A selected from styrene resin, polyalkyl methacrylate and polycarbonate and of a vinyl chloride (co)polymer having 500-2,000 polym. degree (resin B) in 30:70-90:10 weight ratio is kneaded with 10-100wt% plasticizer basing on the amount of the mixture, 5-20wt% stabilizer such as lead chloride basing on the amount of the resin B, and a pigment or a dye added to 1-5wt% wax basing on the amount of the colorant, and the kneaded material is pulverized to obtain a colorant for an electrophotographic developer. By dispersing this colorant and a resin for a toner in a hydrocarbon solvent, a wet developer is obtd., or the colorant is kneaded with a resin for a toner and pulverized to obtain a dry toner. The resulting toner has superior transferrability and fixability.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a colorant for use in wet or dry electrophotographic border agents.

As is well known, there are two types of electrophotographic developers: wet and dry.
A wet developer is a toner whose main components are a colorant and a highly insulating resin for toner, dispersed in a carrier liquid such as an aliphatic hydrocarbon solvent, while a dry developer is a developer in which a colorant is dispersed in a carrier liquid such as an aliphatic hydrocarbon solvent. After melting and mixing together with a carrier such as a toner resin or triiron tetroxide powder, the mixture is pulverized. Known coloring agents used in these developers include pigments or dyes alone such as carbon black, grafted carbon, carbon coated with natural resins, and polymerized dyes. However, these colorants have poor dispersibility in carrier solvents, poor compatibility with toner resins, and poor adhesion, and it is difficult to control particle size. No image was obtained, and the transferability and fixation of the toner image were adversely affected.

The purpose of the present invention is to improve dispersibility in solvents, compatibility with toner resins, and adhesion, and to make it easier to control particle size, thereby improving image density only when used in wet or dry developers. First, it is an object of the present invention to provide a colorant for an electrophotographic developer that can improve the transferability and fixability of toner images.

That is, the colorant of the present invention comprises a resin A selected from the group consisting of styrene resins, polyalkyl methacrylates and polycarbonates, and a resin B selected from vinyl chloride polymers and copolymers having a degree of polymerization of SO, O to 2000. , the resin A
and resin B in an amount of 10 to 100% by weight of a plasticizer, 5 to 20% of a stabilizer to the resin B, waxes of 1 to 5% by weight to the colorant, and a pigment or dye. It is characterized by consisting of. Note that the colorant of the present invention can also be used as a toner.

The colorant itself of the present invention is described in Japanese Patent Publication No. 43-12098 and is well known, but the present invention uses it as an electrophotographic colorant.
It was used as a medicine.

This colorant has excellent processability (particularly crushability), dispersibility, and compatibility, does not adversely affect the physical properties of the colored product, is economically advantageous, and is a non-scattering coloring agent that is convenient to handle. It is introduced in the above publication as an agent. The present inventors have focused on these advantages and have found that all of the above objects can be achieved by using this colorant as a colorant for wet-type or dry-type active agents, and have arrived at the present invention.

The resin used in the colorant of the present invention is at least one of styrene resin, polyalkyl methacrylate, and polycarbonate. Specific examples of styrene resins include polystyrene, styrene-acrylonitrile copolymer,
Examples include α-methylstyrene-acrylonitrile copolymer.

On the other hand, resin B used in combination with these resins A has a polymerization degree of 50.
It is at least one type of vinyl chloride polymer or copolymer of 0 to 200°C. Specific examples of the vinyl chloride copolymer include vinyl chloride-vinylidene chloride copolymer, vinyl chloride-maleic acid copolymer, vinyl chloride-acrylic acid copolymer, vinyl chloride-vinyl acetate copolymer, etc. Can be mentioned. Note that vinyl chloride polymers or copolymers with a polymerization degree of 500 or less have poor heat resistance and light resistance, and also reduce the mechanical strength of the colored resin;
If the number is higher than 00, the gelling temperature is high, which impedes the dispersibility of the pigment or dye, so it is not used. In any case, the resin B is preferably one that is stable against heat, since it is heated due to crosstalk, melting, etc. during coloring processing and colorant production. In this respect, vinyl chloride polymers with few impurities are preferred.

In the present invention, resin A and resin B can be mixed in any ratio, but in practice, the resin A:resin B ratio (weight) is 30; 70.
~90:10, preferably 40:60-80:20
is appropriate. Note that when resin-containing and resin B are mixed and used, when the colorant is manufactured by the cross-wire method, the viscosity becomes larger (becomes rubber-like) compared to the base when resin B is used alone, and the shearing force at the time of cross-wire increases. to promote pigment dispersion. Therefore, resin A
indicates the action of resin B as a dispersion aid. Further, since the resin B imparts brittleness to the product obtained by cooling after the cross-crossing is completed, when the product is pulverized, it exhibits far superior pulverization properties compared to the case of resin B alone.

In the present invention, the plasticizer is the above-mentioned mixed resin (resin A
A component used to lower the softening point of a mixture of resin B and resin B), such as ordinary phthalate esters such as dioctyl phthalate and dibutyl phthalate; aliphatic esters such as dioctyl adipate and dioctyl sebacate. Dibasic acid esters include enoic acid esters such as acetyl tributyl citrate. The amount used is 10 to 200% by weight based on the mixed resin. If it is less than 10%, plasticization will be insufficient and cross-fertilization will be difficult, and if it is more than 200%, the product will become rubbery and cannot be crushed.

Stabilizers are used to enhance the thermal stability of Resin B. The amount used is 5 to 20% by weight based on resin B.

If it is less than 5%, sufficient thermal stability cannot be obtained, and if it is more than 20%, it is not necessary, and if it is used in an excessively large amount, crosstalk will be inhibited. Specific examples of stabilizers include metal soaps, basic lead compounds, organic tin compounds, and the like.

Waxes act as mold release agents during kneading during colorant production, and are not compatible with mixed resins.
Examples of scratch-like waxes that also contribute to improved crushability include liquid paraffin; animal, vegetable, or mineral wax; microcrystalline wax. The amount used is 1 to 5% by weight based on the colorant, but
For mixed resins, the amount is preferably 1 to 25% by weight. If it is less than 1%, it will have little effect as a mold release agent or improve grindability, and if it is more than 5%, it will have poor compatibility with the mixed resin.
The purpose of the present invention cannot be achieved.

Pigments or dyes include carbon black, cobalt pigments, iron pigments, chromium pigments, manganese pigments, mercury pigments,
Examples include sulfide pigments, selenide pigments, alkali blue, phthalocyanine green, oil blue, spirit black, oil violet, phthalocyanine blue, benzidine yellow, methyl orange, brilliant carmine, fast red, and methyl violet. The amount used is preferably as large as possible due to its properties as a coloring agent. Specifically, the amount used varies depending on the type of pigment or dye, and in the case of carbon black, it is the ratio (weight) of the total amount of pigment or dye and other components to 2, respectively.
1:1.0~2.0, 1:0.25~0.6 for pigments other than carbon black, 1:0.8~ for dyes
1.0 is appropriate.

To make the colorant of the present invention, the above ingredients are mixed in a ball mill,
The mixture may be heated and kneaded using two rolls or the like, and after cooling, the resulting mass may be pulverized to a desired particle size.

When the colorant thus obtained is used as a wet boundary agent, it is used as a toner resin and, if necessary, as a polarizer.

A concentrated toner may be prepared by kneading the toner together with a color control agent and a color-adjusting pigment or dye in the presence of a small amount of a solvent, and then dispersing this in a carrier liquid such as an aliphatic hydrocarbon solvent. When used as a dry developer, it may be melt-kneaded together with a carrier such as triiron tetroxide powder, or a toner resin and a color tone adjusting pigment or dye, and after cooling, the resulting mass may be pulverized. In this case, the colorant of the present invention has excellent dispersibility in carrier solvents, compatibility with toner resins, and adhesive properties, and the particle size can be easily controlled. It is possible to make toner with a uniform diameter. High-density images can be formed using toner such as Natako. It is thought that these effects are achieved because other components are sufficiently and uniformly adsorbed by the pigment or dye, and this adsorption power is maintained even during the preparation of the developer.

Examples of the present invention are shown below. Note that all parts are parts by weight.

Example 1 Carbon black 40 parts Degree of polymerization aO
O polyvinyl chloride 22 parts polystyrene
10 parts dioctyl terephthalate 2
1 part liquid paraffin 3 parts montan wax 2 parts barium stearate 2 parts were mixed in a ribbon blender, kneaded for 20 minutes with two rolls with a surface temperature of 140°C, and after cooling, the resulting lump was crushed with a set of hammers. A coloring agent having a particle size of 30 mesh was prepared by pulverizing with a machine. Next layer Coloring agent: 20,000 parts Lauryl methacrylate/methacrylic ratio: 90:10) Copolymer: 400 parts
Disperse 500 parts of 1 part n-hexane with an attritor for 3 hours to obtain a toner particle size of 0.33μ.
A wet type developer was obtained.

Example 2 Cyanine blue 50 parts Polymerization degree 11
00 polyvinyl chloride 20 parts styrene-acrylonitrile copolymer 20 parts dioctyl phthalate 6 parts dibutyltin malate
Part 2 carnauba wax
2 parts in a pan, protected at 150'C with an IJ 4 mixer.

After mixing, the mixture was cooled, and the resulting mass was crushed in the same manner as in Example 1 to prepare a coloring agent having a particle size of 60 mesh. Next, 180 parts lauryl methacrylate glycidyl methacrylate (
Weight ratio 90:10) copolymer 200 parts rosin-modified maleic acid resin 40 parts Isopar L (aliphatic hydrocarbon solvent manufactured by Esso) 500 parts were kneaded in a Kedi mill at 40°C for 2 hours to obtain a toner particle size of 0.32.
A wet developer of μ was obtained.

Example 3 Chrome Yellow 80 parts Polymerization degree 10
00 polyvinyl chloride 8 parts polycarbonate 3 parts tricresyl phosphate 7 parts microcrystalline wax 1.3 parts tribase
0.4 parts barium stearate
0.3 part was mixed with a ribbon blender, kneaded with two rolls with a surface temperature of 120°C, and after cooling, the resulting mass was crushed in the same manner as in Example 1 to give a colored particle size of 30 mesh. A drug was prepared. Next, 100 parts of colorant and 100 parts of triiron tetroxide powder were kneaded for 2 hours using two rolls with a surface temperature of 160°C, cooled, and the resulting mass was crushed and classified using a jet mill to obtain a particle size of 10.8μ.
A dry-type active agent was obtained.

Example 4 High color channel carbon black 30
Polyvinyl chloride with a degree of polymerization of 1500 10 parts Polymethyl methacrylate 16 parts Dibutyl phthalate 39 parts Hoechst wax OP 4.5 parts (synthetic wax manufactured by Hoechst) Cadmium stearate 0.3 parts Barium stearate 0.2 parts Henschel Mix it with a mixer and bring it to a surface temperature of 140℃.
Example 1
A coloring agent having a particle size of 60 mesh was prepared by pulverizing in the same manner as above. Next, 200 parts of a coloring agent (300 parts of an aliphatic hydrocarbon) were dispersed in a Kedi mill for 2 hours to obtain a liquid developer having a toner particle size of 036 μm.

Example 5 100 parts of the colorant prepared in Example 4 and 250 parts of polymethyl methacrylate were heated to a surface temperature of 15
After kneading with two rolls at 0° C. for 2 hours and cooling, the resulting mass was crushed and classified using a jet mill to obtain a dry developer with grains of 91,146”μ.

Example 6 Colorant prepared in Example 1 50 parts Carbon M
Mu 11 10 parts (Carbon black manufactured by Mitsubishi Carbon Co., Ltd.) Polystyrene
600 parts of OA wax (wax manufactured by HALF) was kneaded with two rolls with a surface temperature of 160°C, and after cooling, the resulting mass was crushed and classified using a jet mill to obtain a dry boundary agent with a particle size of 12.4μ. .

Next, each developer obtained as described above is placed in a commercially available wet or dry electrophotographic copying machine to develop the electrophotographic latent image formed on the selenium photosensitive plate, and the resulting image is transferred onto plain paper. After transferring and fixing, the image density, first transfer rate (the ratio of the transferred image to the developed image, calculated from these first density), and image fixation rate (after pasting cellophane tape on the fixing side, peel off the tape, When the ratio of the image after peeling to the image before peeling (calculated from these co-workers' densities) was investigated, the following results were obtained.

(Margin below)

Claims (1)

[Claims] 1. Resin A selected from the group consisting of styrene resin, polyalkyl methacrylate, and polycarbonate, Resin B selected from vinyl chloride polymers and copolymers with a degree of polymerization of 500 to 2000, and the resin A and resin B. Electrophotography consisting of 10 to 100% by weight of plasticizer based on the mixture with resin B, 5 to 20% of stabilizer based on resin B, 1 to 1% by weight of waxes based on colorant, and pigment or dye. Colorant for developer.