JPH05224463A - Electrophotographic toner and production of the toner - Google Patents

Abstract

PURPOSE:To provide an electrophotographic toner capable of improving not only the pulverizing property of a specified binder resin but also of any binder resin easily pulvelizing and producing even by collision and impact method by using a pulverizing aid. CONSTITUTION:This toner contains a thermoplastic binder resin 1, coloring agent 2 which gives color by mixing with the binder resin, and pulverizing aid 3 which facilitates the pulverization of the material containing the binder resin and the coloring agent by impact pulverizer. The pulverizing aid 3 is a mixture of metal salt of triethanolamine and lignosulfonate by (10:1)-(1:10) mixing ratio.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic toner used in an image forming apparatus using an electrophotographic method such as an electrophotographic copying machine and a laser printer, and a method for producing the electrophotographic toner, especially after melt-kneading materials. The present invention relates to an electrophotographic toner manufactured by crushing and a method for producing an electrophotographic toner.

[0002]

2. Description of the Related Art In an electrophotographic copying machine as an image forming apparatus utilizing electrophotography, an electrostatic latent image is formed on a photoconductive photoconductor, and toner is attached to the electrostatic latent image. In general, an apparatus that transfers a toner image to a transfer material such as paper after development is performed. Then, the toner image transferred to the transfer material is further fixed by a fixing device using heat and pressure, and becomes a final copy image.

The electrophotographic toner used in the image forming apparatus utilizing the electrophotographic method as described above is generally manufactured by the following steps. That is, a thermoplastic binder resin which is a main component of the toner, a colorant which is mixed with the binder resin to give a color, and various additives as necessary are mixed as a first step. In the second step, this mixture is melt-kneaded using a kneader at a temperature of 100 to 200 ° C. The kneaded product obtained by this melt-kneading is the third
After cooling in the step of, the powder is crushed. This crushing is performed in two stages. In the first crushing, coarse crushing is performed by repeatedly cutting the kneaded material with a hammer mill having a sharp blade as a fourth step. The coarsely crushed particles are classified as a fifth step to obtain particles having a particle diameter of about several millimeters. As a sixth step, the particles are subjected to a jet mill for finely crushing the particles by using impact of collision to further finely crush the particles. The finely pulverized product thus obtained is classified in the seventh step, and particles having a particle size of 1 to 20 μm become toner.

In the pulverization in the fourth and sixth steps in the above-mentioned manufacturing method, the pulverized material is very hard and difficult to be pulverized, so that the pulverization takes a lot of time. In particular, the fine pulverization in the sixth step requires a long time, the pulverization efficiency is poor, and sufficient toner productivity cannot be increased.

Therefore, in order to increase the crushing efficiency from the past,
Many improvements have been made to crushers. However, even with these improvements, the processing capacity of the crusher within a certain period of time is limited, so it was necessary to review the crushability of the toner material surface in addition to the improvement of the crusher. The hardness of the pulverized material is due to the property of the binder resin which is the main constituent component of the toner. The binder resin is composed of many polymers. This polymer has a plurality of various functional groups, and strong intermolecular attraction acts between the functional groups.
Furthermore, when the polymers are intertwined with each other, a stronger intermolecular attraction acts between the polymers, so that the binder resin becomes hard. Therefore, in order to improve the pulverizability of the toner material, it is necessary to improve the pulverizability of the binder resin.

As an example for solving such a problem,
There is a polyester resin having improved pulverizability as disclosed in JP-A No. 1-179951. However, the binder resin disclosed here is only a polyester-based resin, and when such a specific type of binder resin is used as a toner material, a colorant or an additive to be dispersed in the binder resin is used. There is a drawback that types are restricted and only limited types of toner can be manufactured.

[0007]

As described above, the binder resin used for producing the toner has a poor pulverizability, and it takes a long time to pulverize the binder resin due to a collision impact.
Therefore, it has been necessary to improve the pulverizability of the binder resin. However, for this reason, only by improving and providing a specific type of binder resin, there are restrictions on the types of colorants and additives added to the binder resin, and the poor pulverizability of the binder resin is solved. It has the drawback of not being a fundamental means of doing so.

In the present invention, the grinding aid means a substance added to the toner material in order to shorten the time required for grinding. The present inventors have found that a mixture of a metal salt of triethanolamine and a lignosulfonate as a grinding aid has an excellent effect.

In order to eliminate the above-mentioned drawbacks, the present invention improves the pulverizability of not only a specific binder resin but also any binder resin by means of a pulverization aid, and easily pulverizes it by a collision impact. It is an object of the present invention to provide an electrophotographic toner that can be used and a method for producing an electrophotographic toner.

[0010]

In order to achieve the above object, in the present invention, a thermoplastic binder resin, a colorant mixed with the binder resin to give a color, the binder resin and the colorant. A mixture of a metal salt of triethanolamine and a lignosulfonate in a ratio of 10: 1 to 1:10 as a grinding aid for facilitating the crushing of the material containing To provide a toner for electrophotography.

The present invention further comprises a thermoplastic binder resin,
A toner for electrophotography comprising a step of melt-kneading a colorant mixed with the binder resin to give a color, and a step of rolling and cooling the kneaded product obtained by the melt-kneading and then finely pulverizing it by collision impact. In the production method, in the step of finely crushing by collision impact, a metal salt of triethanolamine and a lignosulfonate are mixed in a ratio of 10: 1 to 1:10 as a grinding aid for improving the grindability of the ground material. Provided is a method for producing an electrophotographic toner, which comprises pulverizing a pulverized material containing 0.01 to 2 parts by weight of the mixture.

[0012]

The binder resin, which is a main constituent of the toner, is an aggregate of crystalline substances composed of many polymers.
When a mixture of a metal salt of triethanolamine and a lignosulfonate is present in such a binder resin, this mixture is mixed in the space formed in the aggregate of the crystalline substance. A binding force acts between the crystalline substances, and the binding force maintains the aggregate structure of the crystalline substances. However, when a mixture of a metal salt of triethanolamine and a lignosulfonate is mixed in this aggregate structure, the above-mentioned binding force is disrupted and the aggregate structure of the crystalline substance is destroyed. The binder resin in which the aggregate structure of the crystalline substance is destroyed is fragile and easily crushed by using a crushing impact.

The mixture ratio of the metal salt of triethanolamine used as a grinding aid and the lignosulfonate is preferably 10: 1 to 1:10. A particularly preferable mixing ratio is 10: 8 to 8:10.

In the present invention, when only one of the metal salt of triethanolamine or the lignosulfonate is added to the toner, the effect as a grinding aid is small, and a mixture of both is used for grinding. The effect as an auxiliary agent appears. Further, the closer the composition ratio of the mixture is to 1: 1, the greater the effect as a grinding aid.

The amount of the mixture of the metal salt of triethanolamine and the lignosulfonate added to the toner material is 0.01 to 2 parts by weight, particularly preferably 0.01 to 2 parts by weight, based on 100 parts by weight of the ground material. 0.1 parts by weight. If the amount added is less than 0.01 parts by weight, the mixture of the metal salt of triethanolamine and the lignosulfonate cannot exhibit the effect as a grinding aid because the amount added is too small. On the contrary, if the mixture of the metal salt of triethanolamine and the lignosulfonate is added to the toner material in an amount of more than 2 parts by weight, the pulverizability is rather deteriorated, which is not preferable. Since the added amount of the mixture of the metal salt of triethanolamine and the lignosulfonate is such a small amount, this additive does not adversely affect the toner properties such as fluidity, chargeability and fixability.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

In the present invention, an electrophotographic toner is manufactured from a toner material having a binder resin 1, a colorant 2, a grinding aid 3 and necessary additives 4 such as a charge control agent as shown in FIG. ..

The toner manufacturing method of the present invention will be described with reference to the flowcharts of FIGS. The manufacturing method of the electrophotographic toner of the present invention relates to a manufacturing method combining a melt-kneading method and a pulverizing method.

(Embodiment 1) First, Embodiment 1 will be described with reference to FIG.

As shown in FIG. 1, first, as a toner material, a binder resin 1, a colorant 2, a grinding aid 3, and an additive 4 such as a charge control agent were prepared. That is, 86,94 parts by weight of styrene-acrylic resin as the binder resin 1 of the toner,
8 parts by weight of carbon black (MA-100, Mitsubishi Kasei) as the colorant 2, 1 each of triphenylmethane derivative (copy blue PR, Hoechst) and quaternary ammonium salt (P-51, Orient Chemical) as the charge control agent
Parts by weight, wax as a release agent (Viscole 660P,
Sanyo Kasei) 3 parts by weight, 1 part of triethanolamine aluminum and calcium lignosulfonate as a grinding aid
0.06 part by weight of a mixture having a composition of 1 was prepared. These prepared materials were mixed in the mixing process of step ST1 to obtain a mixture 5. This mixture 5 was melt-kneaded at about 140 ° C. for 30 minutes using a pressure kneader in the melt-kneading step of step ST2 to obtain a kneaded product 6. The obtained kneaded material 6 was pressed with a roller to a thickness of several millimeters in the pressing step of step ST3, and further plate-shaped and cooled on a cooling belt in the cooling step of step ST4. The kneaded material 6 that has undergone the pressing process of step ST3 and the cooling process of step ST4 is mechanically cut by a hammer mill equipped with a sharp blade in the crushing process of step ST5 until particles with a particle diameter of several millimeters are obtained. Coarsely crushed. The pulverized product obtained in the pulverizing step of step ST5 was divided into particles 7 having a particle diameter of less than 2 mm and particles 8 having a particle diameter of 2 mm or more in the classifying step of step ST6. The particles 7 having a particle size of less than 2 mm were finely pulverized by a jet mill in the fine pulverization process of step ST7 in order to make finer particles. Step ST
In the fine pulverization step of No. 7, an air flow was sent from an air nozzle provided in the jet mill, and particles 7 having a particle size of less than 2 mm were placed on this air flow. Next, this air flow was made to collide at high speed with the collision plate installed in the jet mill in order to give a collision impact to the particles. The particles 7 having a particle size of less than 2 mm were finely pulverized by the impact of this collision. The particles finely pulverized in the fine pulverization step of step ST7 were classified by the classification step of step ST8 into particles 9 having a particle size of 1 to 20 μm. The particles 9 having a particle size of 1 to 20 μm obtained as described above were used as the toner 11.

To improve the fluidity of the obtained particles 9, 0.1 parts by weight of negatively charged silica and 0.2 parts by weight of positively charged silica were added to obtain toner 11.

In the above toner manufacturing process, 15 kg of the kneaded material obtained by melt-kneading was roughly extracted with a hammer mill,
Further, it was finely pulverized with a jet mill, and the time required to reach a predetermined particle size was measured, and it took 36 minutes. This resulted in a 20% reduction in the manufacturing time required when the grinding aid used in Comparative Example 1 below was not used. Further, 94 parts by weight of a ferrite carrier was mixed with the manufactured toner 11 (6 parts by weight) to prepare a two-component developer. This developer is applied to an electrophotographic copying machine (ED-
2510 (manufactured by Toshiba Corp.) was used for copying, and an evaluation test of the copied image was carried out. As a result, an image having the same level of image density as the conventional toner and less fog was obtained.

(Comparative Example 1) Among the toner materials prepared in (Example 1), a mixture of triethanolamine aluminum and calcium lignosulfonate having a composition of 1: 1 was not used, and 87 weight% of styrene acrylic resin was used instead. Parts were changed, and the remaining materials were prepared in the same manner as in (Example 1). The toner material thus prepared was melt-kneaded in the same manner as in (Example 1), and then cooled. 15 kg of the kneaded material thus obtained was crushed by the same method as in (Example 1), and the time required until the crushing was measured was 45 minutes.

As described above, in the manufacturing process of (Example 1), the mixture of the metal salt of triethanolamine and the lignosulfonate is more likely to appear in the jet mill than in the case of pulverization by mechanical cutting with a hammer mill. The effect of the crushing aid 3 is exhibited at the time of crushing by, and the crushing speed of the binder resin is increased. Therefore, the toner is manufactured by the manufacturing process as shown in (Example 2) without using the mixture of the metal salt of triethanolamine and the lignosulfonate as the grinding aid 3 and melting and kneading with other toner materials. Is also good.

(Example 2) As shown in FIG. 2, first, a binder resin 1, a colorant 2, and necessary additives 4 such as a charge control agent were prepared. Polyester resin 86, 9 for the binder resin
4 parts by weight were used, and the same materials as in (Example 1) were prepared for the remaining materials. Similar to the manufacturing process shown in FIG. 1, using these materials, the mixing process of step ST11, the melt-kneading process of step ST12, the pressing process of step ST13, the cooling process of step ST14, the crushing process of step ST15, and the steps. The process up to the classification step of ST16 was performed. Here, the particles 17 having a particle size of less than 2 mm obtained in the classification process of step ST16 are added to the step ST
In the mixing step of 17, the grinding aid 3 is triethanolamine aluminum and 1 of calcium lignosulfonate.
A mixture having a composition of 1 was added and mixed. Step ST17
The mixture 19 obtained in step ST18 is finely pulverized by a jet mill in the fine pulverization step of step ST18, and further step ST19
Particles having a particle size of 1 to 20 μm are classified by the classification process of
0 was obtained as toner 22.

There was almost no change in the grinding efficiency in either of the manufacturing processes of FIG. 1 and FIG.

The toner manufacturing method of the present invention can be modified into various shapes by selecting and using the following materials in addition to the manufacturing methods shown in (Example 1) and (Example 2).

The material of the binder resin 1 may be any commonly known material, for example, polystyrene, styrene / isobutylene copolymer, styrene / butadiene copolymer and styrene / acrylonitrile copolymer. Polystyrene resin, polymethylmethacrylate, ethylmethacrylate, n-butylmethacrylate, acrylic resin such as ethyl acrylate / acrylic acid copolymer, styrene / acrylic copolymer, styrene / diethylamino / ethyl methacrylate copolymer Polymer,
Styrene / butadiene / acrylic acid ester copolymer,
Examples thereof include styrene / butadiene copolymers, styrene / methyl methacrylate copolymers, styrene / methacrylic acid ester copolymer resins such as styrene / n-butyl methacrylate, and polyester resins.

As the colorant 2, a general colorant such as a pigment or a dye is used. Specific substance names are carbon black, nigrosine dye, aniline blue, chalco oil blue, chrome yellow, ultramarine blue, DuPont oil red, orient oil red,
Examples include quinoline yellow, methylene blue chloride and phthalocyanine blue.

As the additive 4, a charge control agent for facilitating the charging of the toner and for holding the charge in the toner, a fluidizing agent for enhancing the fluidity of the toner, and the other toner adheres to the fixing device. There are release agents and the like to prevent

Among the above charge control agents, those which give a positive charge to the toner include quaternary ammonium salts, nigrosine dyes, fluorine activators and hydrophobic silica. Further, as a substance which gives a negative charge to the toner, it is selected from chlorinated polyolefin, chlorinated polyester, metal salt of fatty acid and the like and used.

As the fluidizing agent, there are silicon varnish, metallic soap, nonionic surfactant, hydrophobic silica and the like.

Various waxes can be used as the release agent.

The metal salt of triethanolamine used as the grinding aid 3 is preferably a metal salt of trivalent iron, aluminum, manganese or the like because it is safe and common. As the lignosulfonate, calcium lignosulfonate is widely known.

Further, the obtained toner can be used as a two-component developer by mixing with a carrier, or can be used as a one-component magnetic toner by mixing magnetic particles in the toner. In either case, the mixture of triethanolamine metal salt and lignosulfonate does not adversely affect the carrier or the magnetic particles.

(Example 3) Among the toner materials prepared in (Example 1), 86.94 parts by weight of styrene-acrylic resin was changed to 86.94 parts by weight of polyester resin, and the remaining materials were changed to (Example 1). The same amount of the same material was prepared.
A toner was manufactured from the prepared material in exactly the same manner as in (Example 1).

Further, as in (Example 1), the time required for crushing 15 kg of the kneaded material obtained by melt-kneading was measured, and it took 45 minutes. This resulted in a 25% reduction in the manufacturing time required when the grinding aid used in Comparative Example 2 below was not used.

A two-component developer was prepared in the same manner as in (Example 1) using the manufactured toner, and (Example 1)
A copy was made using the same copying machine as the above, and an evaluation test of the obtained copy image was carried out. As a result, an image having the same level of image density as the conventional toner and less fog was obtained.

Comparative Example 2 Among the toner materials prepared in (Example 3), a mixture of triethanolamine aluminum and calcium lignosulfonate having a 1: 1 composition was not used, but 87 parts by weight of a polyester resin was used instead. For the remaining materials, the same materials as in (Example 3) were prepared in the same amount. The prepared material was melt-kneaded in the same manner as in (Example 1), and then cooled. 15 kg of the kneaded material thus obtained was crushed by the same method as in (Example 1), and the time required for crushing was measured and found to be 60 minutes.

[0040]

As described above, the inclusion of a mixture of a metal salt of triethanolamine and a lignosulfonate as a grinding aid in the toner material improves the grindability of all binder resins.

[Brief description of drawings]

FIG. 1 is a flowchart illustrating a method of manufacturing an electrophotographic toner of (Example 1).

FIG. 2 is a flowchart illustrating a method for manufacturing an electrophotographic toner of (Example 2).

[Explanation of symbols]

 1 Binder Resin 2 Colorant 3 Grinding Aid 11 Toner 22 Toner

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Miho Takigawa 70 Yanagimachi, Saiwai-ku, Kawasaki-shi, Kanagawa Toshiba Yanagimachi factory

Claims (4)

[Claims] 1. A thermoplastic binder resin, a colorant which is mixed with the binder resin to give a color, and a grinding aid for facilitating crushing of the binder resin and the material having the colorant by a crushing impact. An electrophotographic toner comprising a metal salt of triethanolamine and a mixture of a lignosulfonate in a ratio of 10: 1 to 1:10. 2. A step of melt-kneading a thermoplastic binder resin and a colorant mixed with the binder resin to give a color,
In a method for producing an electrophotographic toner, which comprises a step of pulverizing a kneaded material obtained by melt-kneading and then pulverizing it by a collision impact, a pulverization aid for improving pulverizability of a pulverized material is used during the pulverizing step. A method for producing an electrophotographic toner, comprising: 3. A step of mixing and melt-kneading a thermoplastic binder resin and a colorant mixed with the binder resin to give a color, and rolling and cooling the kneaded product obtained by the melt-kneading. A step of pulverizing with a hammer mill, a step of classifying the pulverized product obtained by this pulverization, a step of finely pulverizing the pulverized particles obtained by this classification with a jet mill, and a fine pulverization obtained by this fine pulverization. In the method for producing an electrophotographic toner, which comprises a step of classifying the pulverized material, triethanolamine of 100 parts by weight of the kneaded material is added to the kneaded material as a pulverization aid for improving the pulverizability of the pulverized material in the fine pulverization step. A method for producing an electrophotographic toner, which comprises pulverizing a material to which 0.01 to 2 parts by weight of a mixture of a metal salt and a lignosulfonate is mixed in a ratio of 10: 1 to 1:10. 4. A step of mixing and melt-kneading a material having a thermoplastic binder resin and a colorant mixed with the binder resin to give a color, and a kneaded product obtained by the melt-kneading. After rolling and cooling, a step of pulverizing with a hammer mill, a step of classifying the pulverized product obtained by this pulverizing, a step of finely pulverizing the pulverized particles obtained by this classification with a jet mill,
In the method for producing an electrophotographic toner, which comprises a step of classifying a finely pulverized product obtained by the fine pulverization, 100 weight of the pulverized particles as a pulverization aid for improving pulverizability of the pulverized material in the fine pulverization step. 10 parts by weight of triethanolamine metal salt and lignosulfonate.
A method for producing an electrophotographic toner, which comprises pulverizing a material to which 0.01 to 2 parts by weight of a mixture mixed in a ratio of 1:10 is added.