JPH08254853A - Production of capsulated toner for heat roller fixation and its toner - Google Patents

Abstract

PURPOSE: To easily provide a toner having satisfactory low-temp. fixability and anti-offsetting property in a heat roller fixing system and not causing block ing at ordinary temp. CONSTITUTION: A core material 1 contg. at least a colorant is suspended in water contg. a dispersant by high-speed stirring and it is encapsulated with fine resin particles 2 to obtain the objective capsulated toner. At this time, satd. fatty acid or satd. alcohol having 40-100 deg.C m.p. is used as the core material 1, and after the resin particles 2 are adsorbed, the surface of the core material is fused by heating and the resin particles 2 are fixed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an electrostatic charge image developing toner used in electrophotography, electrostatic printing and the like, and more specifically to a method for producing a capsule toner suitable for heat roller fixing and its production method. Regarding toner.

[0002]

2. Description of the Related Art Electrophotography, which is widely used in copiers and laser printers, generally applies a uniform electrostatic charge on a photoconductive insulator and partially charges the photoimage by irradiating a light image. Erasing is performed to form an electrostatic latent image, and fine powder called toner is attached to a portion where the electrostatic charge remains, and the attached toner is transferred and fixed on a recording paper to obtain a printed matter.

Various systems have been developed for the process of fixing the toner image on the recording paper. Currently, the most common method is the heat fixing method using a heat roller. In this method, the temperature of the heat roller reaches about 180 ° C, and the energy required for the heat roller accounts for most of the energy consumed by the entire device. There is. Recently, due to the demand for energy saving, there has been a strong demand for development of a toner that can be satisfactorily fixed at a lower temperature (about 100 ° C.) than before.

[0004]

However, since a toner using a conventional styrene-acrylic binder or the like has a low-temperature fixing property, it is necessary to use a substance having a low melting point. However, if the colorant, the magnetic substance, and the like are simply dispersed in the low-melting point substance, blocking easily occurs at room temperature.

The present invention is intended to easily provide a toner which has good fixing property at low temperature and anti-offset property in a heat roller fixing system and does not cause blocking at room temperature.

[0006]

In order to solve the above-mentioned problems, the present invention suspends a core substance containing at least a colorant in water containing a dispersant by high-speed stirring, and subsequently, resin fine particles on the surface of the core substance. After adsorption of the resin fine particles, heating is performed to melt the core substance to fix the resin fine particles to the core substance to form a capsule, and a method for producing a heat roller fixing capsule toner, and a method for producing the same The surface of the core substance containing at least a colorant is covered with resin fine particles,
There is provided a heat roller fixing capsule toner, wherein the resin fine particles are partially embedded in the surface of a core material.

Examples of the core substance which can be preferably used in the present invention include n-tridecylenic acid, myristic acid, n-pentadecylenic acid, palmitic acid, margaric acid, stearic acid, n-nonadecylenic acid, arachidic acid and n-heneicosanoic acid. Saturated fatty acids such as phenic acid, n-tricosanoic acid, lignoceric acid, n-pentacosanoic acid, cerotic acid, n-heptacosanoic acid and montanic acid, pentadecanol, hexadecanol, heptadecanol, octadecanol, nonadecanol, Examples thereof include saturated alcohols such as eicosanol, docosanol, tetracosanol, hexacosanol, and octacosanol.

Particularly, saturated fatty acids or / saturated alcohols having a melting point of 40 to 100 ° C. are preferable because the heating temperature of the heat roller can be lowered and the fire extinguishing energy of the electrophotographic apparatus can be reduced. Any appropriate pigment or dye may be used as the colorant. As the dispersant to be added in water, a water-soluble polymer, particularly polyvinyl alcohol is preferable.

In the production of the present invention, first, the above-mentioned core substance such as saturated fatty acid or saturated alcohol is heated and melted, and a colorant, and if necessary, a magnetic material, a charge control agent and the like are dissolved or dispersed therein. This is suspended in water containing a similar heated dispersant by high-speed stirring (1000 rpm or more). While cooling, the mixture is stirred at a low speed (1000 rpm or less) to obtain a suspension of the core substance.

The particle diameter of the core substance is preferably 1 to 20 μm, more preferably 5 to 10 μm. Separately from this, resin fine particles for encapsulation are prepared by emulsion polymerization. Monomers for producing resin fine particles include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-ethylstyrene, 2,4-dimethylstyrene,
p-phenylstyrene, p-chlorostyrene, 3,4-
Dichlorostyrene, pn-butylstyrene, p-te
rt-butyl styrene, pn-hexyl styrene, p
Styrenes such as -n-octyl styrene and pn-dodecyl styrene, olefins such as ethylene, propylene, butylene and isobutylene, vinyl halides such as vinyl chloride, vinylidene chloride, vinyl bromide and vinyl fluoride, acetic acid Vinyl, vinyl esters such as vinyl propionate and vinyl butyrate, methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, n-octyl acrylate, dodecyl acrylate, 2-acrylic acid acrylate Acrylic esters such as ethylhexyl, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n methacrylate
-Butyl, isobutyl methacrylate, n-methacrylic acid
Methacrylic acid esters such as octyl, dodecyl methacrylate, 2-ethylhexyl methacrylate, vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether, acrylic acid or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile, acrylamide, etc. Vinyl-based monomers of

In order to facilitate the adsorption of the resin fine particles to the core substance, it is preferable that the resin fine particles have polarity. For example, it is effective that the monomer contains acrylic acid or methacrylic acid. Further, if a surfactant is used during the polymerization, the toner properties are adversely affected by moisture absorption, and therefore it is preferable to use the soap-free emulsion polymerization without using the surfactant.

The particle size of the fine resin particles is 0.1 to 1 μm, more preferably 0.1 to 0.3 μm. Then, the suspension of the core substance is added to the emulsion of the resin fine particles and stirred to adsorb the resin fine particles on the surface of the core substance. After the adsorption, heating is performed to melt the surface of the core substance, and resin fine particles are fixed to the surface of the core substance to perform encapsulation. The surface of the core substance is substantially covered with the resin fine particles.

After the completion of encapsulation, filtration, washing with water and drying are carried out to obtain a capsule toner. FIG. 1 schematically shows the encapsulated toner of the present invention. In the figure, 1 is a core substance and 2 is a resin fine particle.

[0014]

[Function] Since the core material is a low melting point substance, the temperature of the heat roller can be lowered, and energy can be saved. Moreover, since the surface of the core material is covered with the resin fine particles, blocking at room temperature is prevented. Further, the production of the toner having the capsule structure is simple and low cost.

Examples will be described below, but the present invention is not limited thereto. In addition, "part" and "%" in the examples are based on weight.

[0016]

Example 1 (Production of core material) 8 parts of 20 parts of stearic acid (manufactured by Kanto Kagaku)
Magnetic powder BL-200 (manufactured by Titanium Industry) melted at 0 ° C
13 parts were dispersed. This was placed in 380 parts of a 0.5% polyvinyl alcohol aqueous solution kept at 80 ° C., and a hiscotron (manufactured by Nichine Medical & Scientific Instruments Co., Ltd.) was used to obtain 8000 rpm.
And stirred for 6 minutes to suspend. Promptly add this suspension to 30
It was immersed in water at a temperature of ℃ or below, and cooled with stirring with a glass rod.
The particle size of the suspended particles was about 8 μm. The melting point of stearic acid is about 70 ° C. (Production of Resin Fine Particles) 9 parts of styrene, 1 part of acrylic acid, and 240 parts of water were mixed, and stirring was started at 200 rpm using a three-one motor (manufactured by Rika Ikeda) while substituting with nitrogen at 60 ° C. After 30 minutes, 1 part of potassium persulfate (manufactured by Kanto Chemical Co., Ltd.) dissolved in 50 parts of water was added thereto, and soap-free emulsion polymerization was carried out for 4 hours. The suspended particles had a glass transition temperature of about 70 ° C. with a particle size of about 0.1 μm. (Encapsulation treatment) 33 parts of the core substance and 2 parts of the resin fine particles (both as solid contents) were mixed and stirred at 60 ° C. for 4 hours to adsorb the resin fine particles on the surface of the core substance. 7 more
The resin fine particles were fixed on the surface of the core substance by stirring at 5 ° C. for 1 hour. The yield of the filtered, washed and dried toner is 90%,
The average particle size was 8 μm. No blocking was observed at temperatures from room temperature to 50 ° C. (Printing Test, Fixability Evaluation) 25 parts of the above toner and 75 parts of carrier KTS-1 (manufactured by Hitachi Metals) were mixed to prepare a 1.5-component developer. Using this developer, Fujitsu M38
When a printing test was conducted with a modified machine of a 76M printer and fixing was carried out at 100 ° C., clear printing without offset was obtained. The OD value (optical density) of the solid black portion of this print was measured with a densitometer (manufactured by Konica). A mending tape was attached to the print, a 1 kg weight was rolled from above, the tape was peeled off, and the OD value was measured again.

The fixing ratio was calculated by the following equation (1) to determine the fixing property. The fixing ratio of the above toner at 100 ° C. was 90% or more, which was a good result.

[0018]

[Equation 1]

Example 2 A toner having a yield of 90% and an average particle size of 8 μm was obtained in the same manner as in Example 1 except that methacrylic acid was used instead of acrylic acid. When a printing test was conducted using this toner, clear printing without offset was obtained. Also,
The fixing rate was 90% or more, which was excellent.

Comparative Example 1 The same procedure as in Example 1 was carried out except that the encapsulation treatment was not performed at 75 ° C. As a result, the filter paper was clogged during the filtration, resulting in insufficient encapsulation and resin fine particles. The experiment was discontinued as it was clear that the protein was free. Comparative Example 2 Styrene 1 was used in the production of resin fine particles without using acrylic acid.
When completely the same as in Example 1 except that 0 part was used,
The experiment was stopped because it was clear that the filter paper was clogged during the filtration, the encapsulation was insufficient and the resin fine particles were liberated.

[0021]

As described above, according to the present invention, it is possible to easily provide a toner which is excellent in fixing property at low temperature and anti-offset property in a heat roller fixing system and does not cause blocking at room temperature.

[Brief description of drawings]

FIG. 1 is a sectional view schematically showing a capsule toner of the present invention.

[Explanation of symbols]

 1 ... Core substance 2 ... Resin fine particles

Claims (9)

[Claims] 1. A core material containing at least a colorant is suspended in water containing a dispersant by high-speed stirring, and then resin fine particles are adsorbed on the surface of the core material and then heated to melt the surface of the core material to form a resin. A method for producing a capsulated toner for heat roller fixing, characterized in that fine particles are fixed on the surface of a core material to form a capsule. 2. The method for producing a capsulated toner for heat roller fixing according to claim 1, wherein a saturated fatty acid or a saturated alcohol having a melting point of 40 to 100 ° C. is used as the core substance. 3. The method for producing a capsulated toner for heat roller fixing according to claim 1 or 2, wherein the resin fine particles contain acrylic acid or methacrylic acid. 4. The method for producing a capsule toner for heat roller fixing according to claim 1, wherein the resin fine particles are produced by soap-free emulsion polymerization. 5. A monomer used for producing resin fine particles,
The method for producing a capsulated toner for heat roller fixing according to claim 1 or 2, wherein styrenes, olefins, (meth) acrylic acid esters, vinyl ethers, and (meth) acrylic acid derivatives are used. 6. The method for producing a capsulated toner for heat roller fixing according to claim 1, wherein a water-soluble polymer is used as the dispersant. 7. A heat roller fixing capsule toner, characterized in that the surface of a core substance containing at least a colorant is covered with resin fine particles, and the resin fine particles are partially embedded in the surface of the core substance. 8. The heat roller fixing capsule toner according to claim 7, wherein the core substance is a saturated fatty acid or a saturated alcohol having a melting point of 40 to 100 ° C. 9. The heat roller fixing capsule toner according to claim 7, wherein the resin fine particles are a polymer based on styrenes, olefins, (meth) acrylic acid esters, vinyl ethers or (meth) acrylic acid derivatives.