JPS60262172A - Toner for developing electrostatic charge image - Google Patents

Abstract

PURPOSE:To improve the resistance to stain with vinyl chloride and the offset resistance by blending a styrene-acrylic copolymer with a releasing agent consisting of silicon oil and a metallic salt of fatty acid and a coloring agent. CONSTITUTION:The styrene-acrylic copolymer is blended with a releasing agent consisting of silicon oil and the metallic salt of fatty acid and the coloring agent, and spray drying, grinding or other method are applied to manufacture a toner for developing an electrostatic charge image. A copolymer of styrenes with aliphatic monocarboxylic esters of alpha-methylene can be used as the styrene- acrylic copolymer. Resistance to stain with vinyl chloride is provided by using silicone oil as one component of the releasing agent, and the preferred amount of silicone oil added is 0.1-5wt%. Zinc stearate, cadmium stearate or the like are used as the metallic salt of fatty acid, and it is preferably added by 1- 15wt%.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an electrostatic image transfer toner used in electrophotography, electrostatic recording, electrostatic printing, and the like.

As a developer for developing an electrostatic image formed on a conventional image carrier (ZnO photoreceptor, Se photoreceptor, organic photoconductor, etc.), for example, a developer prepared by mixing magnetic carrier particles and toner particles is used. Two-component developers and one-component magnetic toners consisting of toner particles mainly composed of resin and magnetic powder are commonly used.

Further, the toner image obtained by development can be used as it is, or can be transferred onto a transfer sheet such as plain paper and then fixed to obtain a final image.

The toner image can be fixed using an oven fixing method, in which the toner image is passed through a heated atmosphere using an electric heater, a hot roll fixing method, in which the toner image is passed between a pair of rolls, at least one of which is a heating roll, or a toner image is passed between a pair of rigid rolls at room temperature. A pressure fixing method in which the image is passed through is known.

Among these fixing methods, the heat roll fixing method has extremely high thermal efficiency when fusing the toner image onto the fixing substrate because the surface of the heating roll and the toner image holding surface on the fixing substrate come into pressure contact. Because it is highly effective and can be established quickly,
In particular, it is extremely suitable for image forming apparatuses intended for high-speed copying.

In the heat roll fixing method, the toner is heated and molten and pressure-contacted to the surface of the heat roll, which causes a so-called offset phenomenon in which a portion of the toner adheres to the roll surface and then re-adheres to the substrate to be fixed, staining the image. There are drawbacks that can easily occur.

Therefore, as a method to prevent the offset phenomenon, for example, the heating roll surface is formed of a heat-resistant mold release material such as fluororesin or silicone rubber, and furthermore, an offset prevention liquid such as silicone oil is supplied to the surface. A method is used in which the surface of the roll is coated with a thin film of the liquid.

This method has drawbacks such as heating of the liquid, which generates an odor, and the need for an extra device for supplying the liquid, which complicates the structure of the fixing device.

Therefore, various toners have been proposed in order to obtain a good fixed image without causing offset even without supplying an offset prevention liquid such as silicone oil. For example, Special Publication No. 51-3304, No. 52-3305
No. 57-52574, No. 53-15655, and No. 58-12580 describe toners containing a colorant, a styrene resin, and a specific release agent. Furthermore, Japanese Patent Publication No. 55-6895 discloses that the composition contains an α/β-unsaturated ethylenic monomer as a structural unit, and
A toner containing a resin having a molecular weight distribution within a predetermined range as a main resin component is described.

Problems to be Solved by the Invention According to the above-mentioned known toner, the fixing properties are quite good, but
There are problems in that the resistance to vinyl chloride staining is weak and the resistance to offset is insufficient. An object of the present invention is to provide a toner for developing electrostatic images that solves these problems.

Means for Solving the Problems In order to solve the above problems, the present invention provides a toner for developing electrostatic images containing at least a resin, a colorant, and a release agent, in which the resin is a styrene-acrylic resin. The toner for developing electrostatic images is made of a polymer and contains silicone oil and a fatty acid metal salt as the releasing agent.

It is well known that in the heat fixing method using a hot roll, it is necessary to increase the molecular weight distribution of the resin, ie, the value of weight average molecular weight/thousands of molecular weights, in order to prevent offset. On the other hand, in the case of styrene-acrylic copolymers, resins synthesized by normal polymerization methods often have a molecular weight distribution of 2.0 or more (however, measured by Gale permeation chromatography, the same applies hereafter), and offset Many have a preventive effect.

Therefore, in the present invention, a styrene-acrylic copolymer having a molecular weight distribution of 2.0 or more (preferably 4.0 or more) is used as one of the resin components.

The α/β-unsaturated ethylenic monomer for forming the styrene/acrylic copolymer used in the present invention includes:
For example, styrene, O-methylstyrene, P-methylstyrene, α-methylstyrene, P-ethylstyrene, 2
・4-dimethylethylene, p-n-butylstyrene, P
-tetr-butylstyrene, pn-hexylstyrene, pn-octylstyrene, pn-nonylstyrene.

P-methoxystyrene, P-phenylstyrene.

Styrenes such as P-chlorostyrene and 3,4-dichloroethylene, vinylnaphthalenes, medyl acrylate,
Ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, n-octyl acrylate, dodecyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, acrylic acid Phenyl, α-
Methyl chloroacrylate, propyl methacrylate.

Examples include α-methylene fatty acid monocarboxylic acid esters such as n-octyl methacrylate, dodecyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, and diethylaminoethyl methacrylate.

In the present invention, copolymers of the above-mentioned styrenes and α-methylene aliphatic monocarboxylic acid esters can be used, but
Weight average molecular weight is 50,000 to 3oooooo, number average molecular weight is 10,000 to 50,000, and molecular weight distribution is 3
-30 is preferable, especially 150,000-270
Those having a weight average molecular weight of 000, a number average molecular weight of 25,000 to 35,000, and a molecular weight distribution of 4 to 15 are effective. However, when using a crosslinked resin, it is of course effective even if the resin exceeds this range.

Further, in the present invention, silicone oil is contained as a release agent in order to improve the Δ fret resistance of the toner.

Containing silicone oil prevents the silicone oil from seeping onto the surface of the toner during fixing. Therefore, the compatibility with the plasticizer contained in the PVC sheet is reduced, and resistance to PVC staining is imparted. If the amount added is less than 0.1%, there is no effect, and if it exceeds 5% by weight, the fluidity of the toner decreases due to the viscosity of the silicone oil, so it is preferably 0.1 to 5% by weight.

In addition, since silicone oil alone tends to reduce fluidity and is unfavorable in terms of storage stability, it is recommended to add a fatty acid metal salt having mold release properties in order to compensate for this. 15% weight is good.

Examples of fatty acid metal salts used include zinc salts, cadmium salts, and barium salts of stearic acid.

Lead salts, iron salts, nickel salts, cobalt salts, copper salts, strontium salts, calcium or magnesium salts, zinc salts of oleic acid, manganese salts, iron salts.

cobalt, copper, lead or magnesium salts.

Zinc, cobalt, copper, magnesium, aluminum or calcium salts of balmitic acid.

zinc, cobalt or calcium salts of linoleic acid,
Zinc or cadmium salts of ricinoleic acid.

Known salts such as lead salts of caprylic acid and lead salts of caproic acid can be mentioned.

Any suitable pigment and/or dye can be used as a colorant in the toner according to the present invention. For example, carbon black, aniline blue.

Calco Oil Blue Lamarin Blue, DuPont Oil Red, Quinoline Yellow, Methylene Blue Chloride, Phthalocyanine Blue, Methylene, Malachite Green Ocunarate, Lamp Black, Rose Bengal.

Known dyes include nigrosine dyes and metal-containing (Cr) azo dyes.

Further, when the toner of the present invention is made to have magnetism, in place of some or all of the above-mentioned colorants, iron oxides such as magnetite, hematite, and ferrite, magnetic metals such as cobalt, nickel, and manganese, and magnetic metals such as cobalt, nickel, and manganese may be used. Known fine powders of magnetic materials such as alloys may be used. Here, the content of the magnetic powder is suitably in the range of 20 to 80% by weight based on the total amount of the toner.

The present invention can be produced by a known method such as a spray drying method or a pulverization method using the above-mentioned raw materials.

The toner of the present invention can be mixed with a carrier such as iron powder or ferrite powder to be used as a two-component developer (however, the toner may contain magnetic powder), or it can be used as a two-component developer (however, the toner may contain magnetic powder). It can also be used as

In addition, the toner image formed on the fixing sheet using the toner of the present invention can be well fixed using hot oil without offset, without the need to supply offset prevention liquid to the surface of the toner image. However, as the fixing heating roll, for example, a metal roll whose surface is coated with a fluororesin such as tetrafluoroethylene resin, or a roll made of relatively hard silicone rubber can be used.

Example 1 Methylene/acrylic copolymer (SBM73 manufactured by Sanyo Chemical Co., Ltd.
), silicone oil (KF96 manufactured by Shin-Etsu Chemical), fatty metal salt (zinc stearate manufactured by Seido Chemical), carbon black (#44 manufactured by Mitsubishi Kasei), and negatively charged dye (E83 manufactured by Orient Chemical). Six types of toners shown in Table 1 were prepared.

In preparation, a normal hexane dispersion (10%) of silicone oil was first prepared, and the above raw materials were mixed in a dry mixer, then kneaded in a pressure kneader, and pulverized and classified.

Table 1 Using each of the above-mentioned 1-toners, a developer was prepared at a toner moisture content of 3%, and a commercially available electrophotographic copying machine (UBix3 manufactured by Konishiroku Co., Ltd.) was used.
000ti), the results shown in Table 2 were obtained.

Table 2 (Note 2) PVC stain resistance was evaluated using Okamoto Riken Rubber's APONYL. From Table 2, toners No. 2 to 5 had poor image quality.

Both offset resistance and PVC stain resistance are good, but No. 1t-ner, which does not contain silicone oil, has poor PVC stain resistance and contains too much silicone oil.

6 toner, it can be seen that the fluidity of the toner decreases.

Example 2 Styrene-acrylic copolymer SBM60 manufactured by Sanyo Chemical Co., Ltd.
0), silicone oil (KF96 manufactured by Shin-Etsu Chemical), fatty acid metal salt (zinc stearate manufactured by Seido Chemical), carbon black (#44 manufactured by Mitsubishi Kasei), and negatively charged dye (E83 manufactured by Orient Chemical). 6 shown in Table 3
Created different types of toner. Example 1 using this toner
The developer was prepared in the same manner as above, and an image was created. The results are shown in Table 4.

Table 3 Table 4 (Note 2) PVC stain resistance was evaluated using APONYL manufactured by Okamoto Riken Rubber. From Table 4, the image quality was good for toners N018 to 11.

Toner C has good offset resistance, resistance to PVC staining, and fluidity, but toner No. 7, which does not contain fatty acid metal salts, has poor fluidity, and toner No. 12, which contains too much fatty acid metal salts, has good resistance to PVC staining. I know it's going to get worse.

Effects of the Invention As described above, the present invention provides a method for developing electrostatic images containing at least a resin, a colorant, and a mold release agent, wherein the resin is made of a styrene-acrylic copolymer, and the resin is made of a styrene-acrylic copolymer. Since it contains silicone oil and fatty acid metal salt as a mold release agent, it has the effect of improving vinyl chloride stain resistance and offset resistance.

patent applicant Hitachi Metals Co., Ltd.

Claims (2)

[Claims] (1) An electrostatic image developing toner containing at least a resin, a colorant, and a release agent, wherein the resin is made of a styrene-acrylic copolymer, and the release agent includes silicone oil and a fatty acid metal salt. A toner for developing electrostatic images characterized by: (2) The toner for electrostatic image transfer according to claim 1, which contains 0.1 to 5% by weight of the silicone oil and 1 to 15% by weight of the fatty acid metal salt.