JPH05134457A - Production for electrostatic charge image developing toner - Google Patents

Abstract

PURPOSE:To easily produce a toner containing a charge controlling agent of an irreducible minimum by dispersing a coloring particle into a mixed solvent of water with a water miscible organic solvent in which the charge controlling agent is dissolved and by cooling or dropping water. CONSTITUTION:The charge controlling agent is deposited on the surface of the particle by dispersing the coloring particle made from a binding resin and a dye/pigment into the mixed solvent of water with the water miscible organic solvent in which the charge controlling agent is dissolved and by cooling or dropping water. The charge controlling agent becomes to be in molecular level by dissolving into the water miscible organic solvent. A quantity of water not to deposit the charge controlling agent is mixed with the organic solvent and the coloring particle is dispersed into the mixed solvent. Then by dropping water into the mixed solvent or cooling the mixed solvent to decrease solubility of the charge controlling agent, the charge controlling agent is deposited on the surface of the coloring particle. In this case, the charge controlling agent is deposited on the surface of the toner in molecular level without swelling the coloring particle by the solvent.

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 a toner used in an image forming apparatus such as an electrophotographic copying machine.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus such as an electrophotographic machine, the surface of a photoconductive latent image holding member is uniformly charged, imagewise exposed to form an electrostatic latent image, and the electrostatic latent image is charged. A visible image is formed by developing with the toner, the toner image is transferred to a base material such as transfer paper, and the toner image on the transfer paper is fixed by means such as heating to form an image. The toner used in the image forming apparatus is, for example, a binder resin, a colorant, a toner material such as a charge control agent, and the like are mixed and dispersed using a heating mixer such as a heat roll or an extruder, and a hammer mill, a jet mill, or the like. It is manufactured by a crushing method in which the toner is crushed by the crusher and the toner is classified by a classifier to obtain a toner having a predetermined particle size. Therefore, the charge control agent is uniformly distributed in the toner produced by the pulverization method. However, since the charge control agent present on the surface of the toner particles is greatly involved in the charging of the toner particles, the toner produced by the pulverization method contains a large amount of the charge control agent not involved in the charging inside the particles. Therefore, it is necessary to add a larger amount of charge control agent than necessary. In order to solve this problem, JP-A-2-73371 and JP-A-2-161 are available.
As disclosed in Japanese Patent Publication No. 471, 471, a technique has been proposed in which a charge control agent is mechanically embedded in the toner particle surface using a Henschel mixer, a hybridizer or the like, and the charge control agent is attached to the toner particle surface.

[0003]

However, even if a toner is manufactured using the above technique, it is possible to introduce the charge control agent onto the surface of the toner particles, but the charge control agent should be added in a sufficient amount. It could not be said that the reduction was possible.
Specifically, the amount of the charge control agent required on the toner surface is 0.01 parts by weight with respect to 100 parts by weight of the toner, whereas when the toner having sufficient chargeability is produced by using the above technique. As much as 0.1 parts by weight of the charge control agent is required for every 100 parts by weight of the toner particles. This is because if the charge control agent is evenly distributed at the molecular level on the surface of the toner particles, the charge control agent added most effectively contributes to the charging and the addition amount of the charge control agent to the toner particles is maximized. This is because the charge control agent can be reduced in amount, but in the method of mechanically embedding the charge control agent, the charge control agent is inevitably present in the form of particles on the toner surface. In addition, when used as a toner for a two-component developer, in a toner in which a charge control agent is mechanically embedded, the charge control agent is separated from the toner particles, which contaminates the surface of the carrier particles and reduces the charging property. There was also the problem of making it happen.

An object of the present invention is to solve the above-mentioned conventional problems, and to provide a method for easily producing a toner effectively containing a necessary minimum amount of charge control agent near the surface of toner particles. It is in.

[0005]

In order to achieve the above object, the method for producing an electrostatic charge developing toner of the present invention is a method in which colored particles comprising a binder resin and dyes and pigments are mixed with water in which a charge control agent is dissolved. It is characterized in that the charge control agent is deposited on the surface of the particle by dispersing in a mixed organic solvent and water and cooling or dropping water.

According to the above-mentioned toner manufacturing method, the charge control agent is dissolved in the water-miscible organic solvent, so that the charge control agent is present in the solvent at the molecular level. Water is mixed with the organic solvent to such an extent that the charge control agent is not deposited, and the colored particles are dispersed in the mixed solvent. Therefore, the solubility of the charge control agent is lowered by dropping water into the mixed solvent or by cooling it to deposit the charge control agent on the surface of the colored particles. At this time, since the colored particles hardly swell with the solvent, the charge control agent is not deposited inside the colored particles, and can be uniformly deposited on the surface of the toner at the molecular level. According to the means for dropping water,
The amount of the charge control agent deposited on the toner surface can be easily controlled by adjusting the amount of water dropped. Further, according to the cooling means, the amount of the charge control agent to be deposited can be easily controlled by controlling the cooling temperature. Further, the solvent can be reused after removing the particles on which the charge control agent is deposited.

The colored particles used in the present invention may be those produced by a pulverizing method as long as they have a particle size suitable for use in an image forming apparatus and have a practically sufficient color density. It may be produced by a polymerization method. In the case of the pulverization method, toner materials other than the charge control agent such as synthetic resin and pigment are melt-kneaded, and the kneaded material is cooled and pulverized, and further classified. In the case of production by suspension polymerization, a synthetic resin monomer, a pigment, a polymerization initiator and the like are dispersed in water, and after the polymerization reaction, filtration and drying are performed. In the case of producing by dispersion polymerization, a monomer, a polymerized monomer, and a pigment are dispersed using a surfactant in a mixed solvent of water and a water-miscible organic solvent, followed by a polymerization reaction, followed by filtration and drying. Let In the case of producing by a polymerization method, if the color density is insufficient, it may be further colored by using a disperse dye in water. The particle size of the colored particles is usually 3 μm to 20 μm,
Particularly, those having a range of 5 μm to 10 μm are preferably used. Generally, it is said that particles having a small particle size and a narrow particle size distribution can form higher quality images.

The synthetic resin used in the present invention is a styrene polymer, an acrylic polymer, a styrene-acrylic polymer, an olefin polymer such as polyethylene, polyethylene chloride or polypropylene, polyvinyl chloride, polyester, polyamide, Examples thereof include polyurethane, epoxy resin, diallyl phthalate resin, polyvinyl butyral resin, phenol resin, silicone resin, ketone resin, rosin-modified maleic acid resin, and rosin ester. Among the above resins, as the heat fixing toner, those containing styrene resin, acrylic resin, styrene-acrylic resin, or polyester resin as a main component are preferable. The above resin may have an appropriate molecular weight, but the weight average molecular weight is 10,000 to 200,000, particularly 20,000 to 150.
000 is preferable. Further, the resin has a softening point of 50 to 200 ° C., particularly 70 to 1 in order to improve the heat fixing efficiency.
It is preferably 70 ° C. When the toner is a pressure-fixing toner, an easily plastically deformable resin such as an olefin polymer such as polyethylene or polypropylene, or polyamide is mainly used.

According to the method for producing a toner of the present invention, the colored particles are dispersed in a mixed solvent of a water-miscible organic solvent in which a charge control agent is dissolved and water, and cooled or water is added dropwise.

Examples of the water-miscible organic solvent used in the present invention include lower alcohols such as methanol, ethanol and isopropanol; ketones such as acetone, methyl ethyl ketone and methyl butyl ketone; ethers such as tetrahydrofuran and dioxane; ethyl acetate. And the like; amides such as dimethylformamide are used. This organic solvent is appropriately selected according to the type of charge control agent used.

The charge control agent used in the present invention includes:
It is desirable that the solubility in a water-miscible organic solvent is 0.01 or more, particularly 0.1 or more, and further, the solubility in water is less than 0.01, particularly preferably less than 0.001. For example, Cr complex salt type azo charge control agent, Cr complex salt type alkylsalicylic acid type charge control agent, 1: 2 type Cr complex salt type charge control agent, Zn complex salt type oxycarboxylic acid type charge control agent, Fe complex salt type azo type charge control agent Agent, copper phthalocyanine pigment, and C of salicylic acid, naphthoic acid, dicarboxylic acid
o, Cr, Fe negative charge control agent such as metal complex,
A positively chargeable charge control agent such as a nigrosine compound, an azine dye, a basic dye organotin compound, and a quaternary ammonium salt is used.

The amount of the solvent in which the colored particles are dispersed and the amount of the charge control agent dissolved in the solvent vary depending on the combination of the charge control agent and the solvent. Generally, the amount of the charge control agent required for the colored particles is 0.01% by weight, so that 0.03 to 0.1% by weight of the charge control agent for the colored particles may be present in the solvent. preferable. Further, the amount of the water-miscible organic solvent added is an amount sufficient to dissolve the charge control agent,
Generally, 1000 to 10000 parts by weight of the charge control agent is required. If the amount of the water-miscible organic solvent is too large, it will be difficult to deposit the charge control agent, and if it is too small, the charge control agent will not be completely dissolved, making it impossible to produce an excellent toner. The amount of water mixed in the solvent is
Most preferably, the charge control agent dissolved in the water-miscible organic solvent is contained as much as possible so as not to precipitate.

The mixed solvent in which the colored particles are dispersed is cooled, or water is dropped to reduce the solubility of the charge control agent to deposit the charge control agent on the surface of the colored particles. When cooling, it is preferable to gradually cool the dispersion liquid at a rate of about 1 to 3 ° C./min while stirring the dispersion liquid so that the charge control agent is uniformly deposited on the surface of the colored particles. Also, when water is dropped, the dispersion liquid is stirred so that the charge control agent is uniformly deposited on the surface of the colored particles, and the content of the dispersion liquid is 0.5 to 2.0% by weight of the dispersion liquid per minute. It is preferable to add the amount dropwise.

As described above, by depositing the charge control agent on the surface of the colored particles, and then filtering and washing and drying, an electrostatic charge having excellent performance effectively introduced into the surface of the charge control agent. Toner for development is manufactured.

[0015]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited thereto.

Example 1 (When Producing Colored Particles by Suspension Polymerization) In a reaction vessel, 400 parts by weight of water, 6 parts by weight of tricalcium phosphate, concentrated hydrochloric acid, and 0.01 parts by weight of sodium dodecylbenzenesulfonate were added. Was added, and the mixture was stirred and uniformly dissolved, and then a mixture of the following components was added. Monomer: Styrene 80 parts by weight Butyl methacrylate 20 parts by weight Divinylbenzene 1.8 parts by weight 2-Ethylene glycol dimethacrylate 1.5 parts by weight Polymerization initiator: 2,2′-azobis (2,4-dimethylvaleronitrile) ) 10 parts by weight Pigment: carbon black (MA-100 manufactured by Mitsubishi Kasei) 5 parts by weight Offset inhibitor: low molecular weight polypropylene (viscor 550P manufactured by Sanyo Kasei) 2 parts by weight

Next, the above mixture was granulated into about 10 ml of oil droplet particles, an aqueous solution of sodium hydroxide was added thereto to precipitate tricalcium phosphate to form a protective colloid, and then 80
The reaction was carried out at 0 ° C for 10 hours. After completion of the reaction, the product was separated from the reaction solution by filtration, treated with dilute hydrochloric acid, washed with water and dried to obtain black resin particles having a particle size of about 10 μm.

100 g of black resin particles and 0.05 g of charge control agent (Bontron S-34 manufactured by Orient Chemical Industry Co., Ltd.)
Dispersed in a mixed solvent of 300 g of water and 200 g of methanol,
Dissolve and raise the temperature to 40 ° C. About 30 at the same temperature
After stirring for 1 minute, the mixture was cooled with stirring at a rate of about 2 ° C./min, filtered, washed and dried to obtain a black toner.

The amount of the charge control agent introduced on the surface of this toner was about 0.01 wt%. A developer was prepared by mixing the toner and the ferrite carrier, and the charge amount was measured using a blow-off charge amount measuring device (manufactured by Toshiba Chemical Co.). -33.3 μC / g, and −23.0 μC / g under high temperature and high humidity (35 ° C., 85%) conditions, and almost no change in charge amount due to environmental changes was observed. Further, when the above-mentioned developer was mounted on an electrostatic copying machine (manufactured by Mita Industry Co., Ltd., DC-1205) and a copying test was conducted under the same conditions as described above, a good image was obtained in any case. Was given. Further, a normal image was maintained after continuous copying (running test) of 100,000 sheets in the electrostatic copying machine.

Example 2 (When Producing Colored Particles by Grinding Method) A mixture of the following components was melt-kneaded using a biaxial kneader,
This kneaded product is cooled, pulverized, and further classified to have a central particle size of 1
0 μm black resin particles were obtained. Styrene-butyl acrylate copolymer 100 parts by weight Carbon black (Mitsubishi Chemical Co., MA-100) 10 parts by weight Low molecular weight polypropylene (Sanyo Chemical Co., Ltd. Viscole 550P) 5 parts by weight

Next, 100 g of the above black resin particles and a charge control agent (TP-302 manufactured by Hodogaya Chemical Co., Ltd.)
Disperse and dissolve 0.05 g of water in a mixed solvent of 300 g of water, add 200 g of water at a rate of 5.0 ml / min with stirring using a micro feeder manufactured by Furue Science Co., Ltd., then filter, wash, and dry to obtain black. Toner was obtained. The amount of charge control agent introduced on the surface of this toner is about 0.01 w.
It was t%. A developer was prepared by mixing the toner and the ferrite carrier, and the charge amount was measured using a blow-off charge amount measuring device (manufactured by Toshiba Chemical Co.). Under normal temperature and normal humidity conditions (20 ° C., 65%), +32.3 μC /
g, + 31.6μ under conditions of high temperature and high humidity (35 ℃, 85%)
C / g, and almost no change in charge amount due to environmental change was observed. Further, when the above developer was mounted on an electrostatic printer (LPX-1 manufactured by Mita Kogyo Co., Ltd.) and a copying test was conducted under the same conditions as described above, a good image was obtained in any case. It was Further, a normal image was maintained after continuous copying (running test) of 100,000 sheets in the electrostatic printer.

Example 3 (When Producing Colored Particles by Dispersion Polymerization Method) 200 g of isopropyl alcohol and 40 g of water were placed in a 500 ml separable flask, and then 3 g of polyacrylic acid was dissolved. Next, 45 g of styrene, 12 g of butyl acrylate, and 5 g of 2,2′-azobisisobutyronitrile were added and reacted at 70 ° C. for 12 hours while stirring at a stirring speed of 500 rpm under a nitrogen stream. After completion of the reaction, the reaction product was filtered from the reaction solution, washed and dried to obtain white resin particles having a particle size of about 6 μm. Next, 50 g of the above-mentioned white resin particles are mixed with anthraquino type dye (Mitsui Toatsu Co., Ltd., SPR
Black # 200) and 10 g of water were dispersed in 500 g of water, and dyeing treatment was performed at 120 ° C. for 2 hours while stirring in an autoclave to obtain black resin particles.

100 g of the above black resin particles and 0.05 g of a charge control agent (Kayaset Black T-3 manufactured by Nippon Kayaku Co., Ltd.) were dispersed and dissolved in a mixed solvent of 300 g of water and 400 g of methanol, and the temperature was raised to 40.degree. After stirring at the same temperature for about 30 minutes, the mixture was cooled with stirring at a rate of about 2 ° C./min, filtered, washed and dried to obtain a black toner.

The amount of charge control agent introduced onto the surface of this toner was about 0.01 wt%. A developer was prepared by mixing the toner and the ferrite carrier, and the charge amount was measured using a blow-off charge amount measuring device (manufactured by Toshiba Chemical Co.). -43.3 μC / g and -43.0 μC / g under high temperature and high humidity (35 ° C., 85%) conditions, and almost no change in charge amount due to environmental change was observed. Further, when the above-mentioned developer was mounted on an electrostatic copying machine (manufactured by Mita Industry Co., Ltd., DC-1205) and a copying test was conducted under the same conditions as described above, a good image was obtained in any case. Was given. Further, a normal image was maintained after continuous copying (running test) of 100,000 sheets in the electrostatic copying machine.

Comparative Example 1 In Example 1, the same evaluation as in Example 1 was performed on the black particles in which CCA was not introduced on the surface. As a result, the charge amount at room temperature and normal humidity was -12.3 μC / g, and when it was mounted on an electrostatic copying machine, toner scattering and fog occurred and a normal image could not be obtained.

Comparative Example 2 100 g of the black particles synthesized in Example 1 and a charge control agent (Bontron S-34 manufactured by Orient Chemical Industry Co., Ltd.)
5 g Water 200 g and methanol 300 g are dispersed and dissolved in a mixed solvent, and the temperature is raised to 400 ° C. After stirring at that temperature for about 30 minutes, the mixture was cooled with stirring at a rate of about 2 ° C./min, filtered, washed and dried to obtain a black toner. A developer was prepared by mixing the toner and the ferrite carrier, and the charge amount was measured using a blow-off charge amount measuring device (manufactured by Toshiba Chemical Co.).
0 ° C., 65%)-24.2 μC / g, and high temperature and high humidity (35 ° C., 85%)-24.0 μC / g, almost no change in charge amount due to environmental changes. It was However, when the above-mentioned developer was mounted on an electrostatic copying machine (manufactured by Mita Kogyo Co., Ltd., DC-1205) and a copying test was conducted at room temperature and normal humidity, the charge amount decreased as the copy volume increased, and the toner Scattering occurred and normal images were not formed.

[0027]

EFFECTS OF THE INVENTION According to the present invention, a toner containing a necessary minimum amount of charge control agent near the surface of toner particles can be easily manufactured.

Claims (1)

[Claims] 1. The surface of the particles is obtained by dispersing colored particles comprising a binder resin and a dye / pigment in a mixed solvent of a water-miscible organic solvent in which a charge control agent is dissolved and water, and cooling or dropping water. A method for producing a toner, comprising depositing a charge control agent on the toner.