JPH0243565A - Toner for electrophotography - Google Patents

Abstract

PURPOSE:To obtain a copied image having the image quality of high glossiness and to eliminate the need for use of a binder component having a low mol. wt., the increase of a fixing temp., etc., by incorporating >=5wt.% polyalkylene into the toner. CONSTITUTION:This toner contains the binder component and the coloring agent and is formed by incorporating >=5% polyalkylene by the weight of the total binder component into the toner. Namely, the toner is produced by heating the melting the polyalkylene, the binder component and the coloring agent, and kneading the mixture, then solidifying the mixture by cooling and grinding the cooled mixture. The polyalkylene may be merely incorporated into the binder component of the toner and may also be incorporated in the form of a graft copolymn. with the binder resin component or may be further added as an external additive of the toner to the toner. The highly glossy image is obtd. in this way by using a low-temp. fixing device and without using the polymer of the extremely low mol. wt.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention This invention relates to electrophotographic color toners for developing electrostatic latent images.

BACKGROUND OF THE INVENTION Conventionally, electrophotographic toners for developing electrostatic latent images in electrophotography include resins such as polystyrene, styrene-butadiene copolymers, and polyesters, and pigments or dyes such as carbon black and phthalocyanine blue. was used as a coloring agent, and after melt-kneading, 1 μ/lI ~ 30 pm
Toner obtained by pulverizing toner and glass peas whose average particle size is approximately the same as that of the toner or up to 500 mm,
Particles of iron, nickel, ferrite, etc., or a mixture of these and a carrier coated with various resins are generally used.

However, with these toners, a copy image with high gloss cannot be obtained. Generally, full-color toners, full-color inking black toners, and the like are desired to have high gloss in order to improve image quality. Therefore, methods such as (1) raising the fixing temperature, ■ using low molecular weight resin, etc. have been tried, but ■ high power consumption, ■ low molecular weight makes the toner brittle and may adhere to the photoreceptor. When a two-component developer is used, problems such as shortening of the life of the developer occur due to carrier invasion.

Therefore, it is an object of the present invention to provide a toner that can produce high gloss images using a low temperature fuser and without using extremely low molecular weight polymers.

Problems to be Solved by the Invention The color toner for electrophotography of the present invention contains a binder resin and a colorant, and contains polyalkylene in an amount of 5% by weight or more, preferably 5 to 15% by weight based on the total binder resin. %.

Hereinafter, the electrophotographic color toner of the present invention will be explained in detail.

Examples of the polyalkylene added in the present invention include polyethylene and polypropylene. These polyalkylenes having a molecular weight in the range of 2,000 to 6,000 are preferably used.

These polyalkylenes may be simply mixed into the binder resin of the toner, but may also be contained in the form of graft copolymerization with the binder resin component. Furthermore, it may be added as an external additive to the toner.

In the present invention, polyalkylene must be contained in an amount of 5% by weight or more based on the total binder resin. If the content of polyalkylene is lower than 5% by weight, the glossiness of the copied image will decrease. Glossiness increases with the content of polyalkylene, but when the content exceeds 15% by weight, infiltration into the carrier begins to increase, and when copying a large number of sheets, fogging occurs on copied images and image quality deteriorates. . Therefore, in order to obtain a high gloss image, the polyalkylene content is preferably in the range of 5 to 15% by weight.

In the present invention, known toner particles are used.

As the binder resin, any thermoplastic resin can be used; specifically, styrenes such as styrene and chlorostyrene; monoolefins such as ethylene, propylene, butylene, and isobutylene; and acetic acid. Vinyl esters such as vinyl, vinyl propionate, vinyl benzoate, vinyl butyrate: methyl acrylate, ethyl acrylate, butyl acrylate, dodecyl acrylate, octyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, methacrylate α-methylene aliphatic monocarboxylic acid esters such as butyl methacrylate and dodecyl methacrylate; vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, and vinyl butyl ether; vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, and vinyl isopropenyl ketone; Examples include polymers and copolymers. Particularly typical binder resins include polystyrene, styrene-alkyl acrylate copolymer, styrene-alkyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, and styrene-maleic anhydride copolymer. Polymers can be mentioned. Additionally, polyesters, polyurethanes, polyamides and modified rosins can be avoided.

In addition, toner colorants include carbon black, nigrosine, aniline blue, calcoyl blue, chrome yellow, ultramarine blue DuPont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue, malachite green oxalate,
Lamp black, rose bengal, C,! , Pigment Red 48; 1, C, 1, Pigment Red 122
, C,1, Pigment Red 57:1, c,r, Pigment Yellow 97, C,1, Pigment Yellow 12, C,1, Pigment Blue 15:1, C,1,
Pigment Blue 15;3 can be exemplified as a typical example.

In the present invention, the binder resin and colorant are not limited to those exemplified above.

Further, an internal charge control agent may be included if necessary. Furthermore, it may contain magnetic powder or the like.

The toner of the present invention can be produced by heating and melting the polyalkylene, binder resin, and colorant, kneading, cooling, solidifying, and pulverizing.

The average particle size of the toner of the present invention is less than about 3o4;
Preferably it is set in the range of 3 to 20 μm.

Furthermore, external additives may be attached to the toner particles. Examples of the external additive particles include silica particles, hydrophobic silica particles, metal oxide particles, polyvinylidene fluoride particles, and polymethyl methacrylate particles, but particles other than these can also be used.

The toner of the present invention may be used as a one-component developer consisting only of toner particles, or may be used as a two-component developer consisting of a mixture of carrier and toner.

As a carrier in a two-component developer, an average particle size of 50
Particles up to 0 #l can be used, and any known particles can be used, such as iron, nickel, cobalt, iron oxide, ferrite, glass beads, granular silicon, etc. Further, the surfaces of these particles may be coated with a coating agent such as fluororesin, acrylic resin, silicone resin, or the like.

The developer of the present invention can be used to develop an electrostatic latent image formed on a photoreceptor or an electrostatic recording medium. That is, an electrostatic latent image is electrophotographically formed on a photoreceptor made of an inorganic photoconductive material such as selenium, zinc oxide, cadmium sulfide, or amorphous silicon, or an organic photoconductive material such as a phthalocyanine pigment or a bisazo pigment; An electrostatic latent image is formed on an electrostatic recording medium having a dielectric material such as polyethylene terephthalate using a needle-like electrode, and the developer of the present invention is applied to the electrostatic latent image by a developing method such as a magnetic brush method or a cascade method. to form a toner image.

After this toner image is transferred to a transfer material such as paper, it is fixed and becomes a copy, and the toner remaining on the surface of the photoreceptor is cleaned. As the cleaning method, various methods can be used, such as a blade method, a brush method, a wear method, and a roll method.

Example Hereinafter, the present invention will be specifically explained with reference to Examples.

Example 1 Styrene-n-butyl acrylate copolymer y parts by weight (weight ratio 85
:35) C,1, Pigment Blue 15:3 10 parts by weight Polyethylene (1lW=2000) X parts by weight, where x 10y = 100 parts by weight.

The above ingredients are melt-kneaded, pulverized, and classified to have an average particle size of 12
Moe blue toner particles were obtained.

In other words, the amount of polyethylene is 0.3.5.7.
9.11.13.15.17.19.21 parts by weight of each toner particle, 1q. A toner was prepared by adding 0.5 parts by weight of fine silicon oxide powder and 1.0 parts by weight of fine tin oxide powder as external additives to these toner particles.

Styrene is added to the ferrite particles with an average particle size of 1100 Ji.
A carrier coated with n-butyl methacrylate-methyl methacrylate copolymer was used as a carrier and mixed with the above toner to obtain a developer. Put each developer into the developing machine of a copying machine (X3870, manufactured by Fuji Xerox ■) equipped with a magnetic brush developing machine, take multiple copy samples, and measure the glossiness using Digital Gloss G) Model I-26075 (Murakami Color Technology). In addition, the amount of charge of the toner and the image quality of the copied image were evaluated.The results are shown in Table 1 and FIG.

In Table 1, Q indicates that the toner area coverage on the photoreceptor is 0.2% or less, and Δ indicates that the toner area coverage is 0.2% or less.
3%, × means that the toner area coverage exceeds 0.3% and is gold.

Example 2 Propylene polymer (1w=4000) and styrene-n
- Graft polymer of butyl methacrylate copolymer (
With respect to 100 parts by weight of this graft polymer, 95 parts by weight of polypropylene (9 parts by weight) and 1225 parts by weight of C,1, pigment red are melt-kneaded, pulverized, and classified to produce red toner particles with an average particle size of 12JIIft. I got it.

Comparative Example 1 Styrene-n-butyl acrylate copolymer 90 parts by weight (weight ratio 6
5:35) C,1, Pigment Blue 15:3 10 parts by weight The above ingredients were melt-kneaded, pulverized, and classified to obtain an average particle size of 12
JIIrI blue toner particles were obtained.

Comparative Example 2 Styrene-n-butyl acrylate copolymer 95 parts by weight (weight ratio 6
5:35) C, 1, Pigment Red 1225 parts by weight The above components were melt-kneaded, pulverized, and classified to obtain red toner particles with an average particle size of 12 mm.

A developer was obtained in the same manner as in Example 1 using the toner particles of Example 2 and Comparative Examples 1 and 2 above. Using each developer, the glossiness was measured in the same manner as in Example 1. The results are shown in Figure 1.

From the above results, it is clear that the glossiness is about 15 to 20% lower in toners that do not contain polyalkylene. Furthermore, when the polyalkylene content is 5% or more, the gloss level clearly increases, and as the content increases, higher gloss levels are obtained. However, when the amount exceeds 15%, the interference to the carrier begins to increase, and when copying 10,000 sheets using a copying machine (FX3870), fogging begins to appear in the copied image, and image quality deterioration becomes severe. Therefore, it can be seen that in order to obtain a high-gloss image, the polyalkylene content is preferably in the range of 5 to 15 weight percent.

Effects of the Invention Since the color toner for electrophotography of the present invention contains polyalkylene in an amount of 5% by weight or more as described above, a copy image having high glossiness and image quality can be obtained. therefore,
It is no longer necessary to use a low molecular weight binder resin to obtain high gloss, there is no need to change the fixing temperature, and there is also no need to change the fixing temperature. It is possible to prevent it from becoming life-threatening.

[Brief explanation of the drawing]

FIG. 1 is a graph showing the relationship between polyalkylene content and glossiness. Patent applicant Fuji Xerox Co., Ltd. Agent
Patent Attorney Dobe Gowax Contains 1 (wt%) Figure 1

Claims (1)

[Claims] (1) A color toner for electrophotography containing a binder resin and a colorant, which contains polyalkylene in an amount of 5% by weight or more based on the total binder resin. (2) The color toner for electrophotography according to claim 1, wherein the content of polyalkylene is 5 to 15% by weight based on the total binder resin.