JPS5897056A - Toner for electrostatic charge development - Google Patents

Abstract

PURPOSE:To prevent an offset development and fog, by using a styrene resin, an electric charge imparting agent and low molecular weight PP as toners for heat- roll fixing, and by making the dispersing property better by kneading the PP and the electric imparting agent preliminarily. CONSTITUTION:An electric charge imparting agent such as a nigrosine dyestuff is heat-kneaded into low mol.wt. propyrene PP having 2,000-30,000mol.wt. and this is dispersed well preliminarily. A styrene resin only or a binder resin in which a polyester resin is mixed, an electric charge imparting agent and carbon black are mixed to this substance and further is kneaded and dispersed. Although the PP is not well soluble in the charge imparting agent, they are well dispersed and soluble by dispersing preliminarily. This kneaded toner is pulverized to make in powders having a prescribed size and is added with iron powders to obtain a developer. By fixing with this developer by a heat roll method, an offset development in which the toner is stuck on the heat roll is eliminated and an excellent picture having no fog is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a round toner for developing electrostatic images in electrophotography and the like. More specifically, the present invention relates to a toner for electrostatic charge development that exhibits good fixing properties particularly in the hot roll fixing method and has excellent durability without causing 4-capri fraying even after repeated copying.

In electrophotography, the one-oven fixing method, flash fixing method, hot roll fixing method, etc. are known as methods for thermally fixing toner images according to electrostatic charge images, but the hot roll fixing method uses heating. It is particularly effective because the heater capacity used for rounding is relatively small, and the apparatus can be designed in a small size and at a wide range of copying speeds, from very high to medium to low. However, in this method, the surface of the hot roll and the toner image come into contact in a heated and molten state, so a part of the toner image adheres to the hot roll and the toner is transferred onto the next transfer paper, which is a so-called offset phenomenon. This may cause stains on the transfer paper.

Conventionally, attempts have been made to improve this problem by adding low molecular weight polypropylene. However, P-pyrene, a polypropylene with a large molecular weight, has extremely poor compatibility with a charge imparting agent added to improve the band characteristics of the toner, and this charge imparting agent cannot be used in conventional toner manufacturing methods. Cannot be uniformly dispersed in low molecular weight polypropylene. Therefore, repeated copying tends to cause fogging and the durability is insufficient.

The present inventors kept this point in mind and as a result of further studies, they learned that if the charge imparting agent was dispersed in low molecular weight polypropylene in advance, the intended purpose could be achieved. I have reached the point where I have completed the .

That is, the gist of the present invention resides in an electrostatically charged toner for present use, which is obtained by kneading a styrene resin and/or a polyester resin, a charge imparting agent, and a low molecular weight polypropylene containing the charge imparting agent dispersed therein.

A copolymer of is used as the resin component.

Styrene monomers include styrene, 〇-methylstyrene, m-methylstyrene, p-methylstyrene, p-
Ethylstyrene, λ, date dimethylsterene, p-n-
Butylstyrene, P-tert-butylstyrene, P
-n-hexylstyrene and styrene derivatives are used. Other vinyl monomers include, for example, ethylenically unsaturated monoolefins such as ethylene, propylene, butylene, and isobutylene; vinyl chloride; vinyl halides such as vinylidene chloride; vinyl acetate, vinyl butyrate, etc. Vinyl esters, methyl acrylate, ether acrylate, n-butyl acrylate, coethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, n-methacrylate Examples include α-methylene aliphatic monocarboxylic acid esters such as octyl and coethylhexyl methacrylate.

In addition, polyester resins include polybasic acids such as adipic acid, sebacic acid, 7-thalamic acid, isophthalic acid, and terephthalic acid, and ethylene glycol, 1, J-propanediol, 1, .Use a polyester resin produced by an esterification reaction with a polyhydric alcohol such as 3-butanediol, hehiro-butanediol, /, Z-bentanediol, 7.4-hexa/diol, neopentyl glycol, etc. In the present invention, a mixture of these styrene resins and polyester resins can be used.

Various known charge imparting agents can be used, including nigrosine dyes, triphenylmethane dyes and chromium-containing metal complex dyes.

Examples of nigrosine dyes include Orient Spirit Blackum B1 Orient Spirit Black 8B, Nigrosine Oil Black Σx1 Rubent Black φj1φ7 (trade name: Orient Kagakuten), Spirit Black AIjO, Spirit Black Muta O
O (trade name, manufactured by Sumitomo Chemical) is mentioned.

Examples of triphenylmethane dyes include the following.

Further, examples of the chromium-containing metal complex dye include Zabonp 2 Tsuku RE and Bali 7 First φ3 Rott (FM product name, Orient Chemical Exhibition). Low molecular weight polypropylene usually has a molecular weight of 000 to 30,000,
Good, Mashuke, Hiroshi, 000~/! , 000 are used.

In the present invention, the low molecular weight polypropylene to be kneaded with the styrene resin and/or polyester resin and the charge imparting agent contains the desired charge imparting agent dispersed in advance.

As the charge imparting agent, the same ones as mentioned above can be used. Such a charge imparting agent is added to heat-molten low molecular weight propylene, and a nine-image molecular weight polypropylene is obtained by uniformly dispersing and containing the charge imparting agent by a melt dispersion method of stirring. When using the low molecular weight polypropylene thus obtained, it is pulverized and classified if necessary.

The charge imparting agent to be dispersed and contained in the low molecular weight polypropylene is /-1 parts by weight of the low molecular weight polypropylene.
00 parts by weight, preferably from 2 to 50 parts by weight.

The toner of the present invention contains a styrene resin and/or polyester resin, a charge imparting agent, and a low molecular weight polypropylene containing a charge imparting agent dispersed therein in the toner composition, and the styrene resin and/or polyester resin is 1. j ~ 75 weight, preferably ali,! ~rz, z weight-1 charge imparting agent is 0. s~io weight-1 preferably o, z~! Weight -
It is obtained by adding low molecular weight polypropylene in an amount of /~is weight - 1 preferably / - 10 weight - and cross-mixing, crushing and classifying in a conventional manner.

The toner of the present invention contains carbon black in addition to the above-mentioned styrene resin, polyester resin, charge imparting agent, and low molecular weight polypropylene O containing the charge imparting agent dispersed therein. In the present invention, a portion of the carbon black used may be previously dispersed and contained in low molecular weight polypropylene together with a charge imparting agent. Various known carbon blacks can be used. For example, Mitsubishi Carbon Plant ◆30. ◆J co,
φ33, φ−0, ←0, φda! , φgo, φjj, ◆j
j1φtoo.

MA-t, MA-//, MA-100SM Mu 400,
MOIF-if (trade name, manufactured by Mitsubishi Kasei Corporation) etc. Carbon black is usually 7 to 10 parts by weight of styrene resin and/or polyester resin and low molecular weight polypropylene. Parts by weight are used.

The toner of the present invention may further contain various additives that are normally added to toners, such as other coloring pigments, if necessary. These additives are used in the toner composition in amounts ranging from 1 to 70% by weight.

In this way, a toner with good dispersibility of the charge imparting agent can be obtained.One toner of the present invention can be used in combination with a known carrier such as iron powder.
Limited to 1, but/! Iron powder having a particle size of 0 to 4400 mesh is preferably used. The toner is usually used in the range of J-/j parts by weight based on the carrier i0y parts by weight.
' If a copying machine is used to copy the ** agent obtained by combining the toner mainly composed of the styrene resin and/or expanded polyester resin of the present invention as explained above with a carrier, it will be printed on a heated roll. On the other hand, the present invention was demonstrated by J! Although the present invention is not limited to the following, low molecular weight polypropylene (molecular weight: fi/I O'CK Warm and melt for 30 minutes.

Next, 301 g of Nigrosine Oil Black IeX (manufactured by Orient Chemical Co., Ltd.) was added and uniformly dispersed for 30 minutes by stirring. After homogeneous dispersion, it was cooled and pulverized to obtain a low molecular weight polypropylene sample containing the JOOI charge imparting agent dispersed therein.

3 parts by weight of this sample and styrene resin Hymer BBM-4
Parts by weight of ioo 00 (manufactured by Mitsubishi Kasei Corporation), 5 parts by weight of carbon black Mmut (manufactured by Mitsubishi Kasei Corporation), and 5 parts by weight of Nigrosine Oil Black EX (manufactured by Orient Chemical Co., Ltd.) were melted and kneaded, and further crushed and classified. A toner having an average particle size of is μ was obtained. 4 parts by weight of this toner was mixed with 100 parts by weight of iron powder having a particle size of /jO-λjo mesh, and used in a hot roll fixing type copying machine using zinc oxide as a photoreceptor! 0.
After making 000 copies, it showed excellent mold releasability and
It was found that the developer produced copies with less capri and exhibited high durability.

Example - Low molecular weight polypropylene 3001 with molecular weight /≠,000
A low molecular weight polypropylene sample containing a dispersed charge imparting agent was obtained in exactly the same manner as in Example 7, except that 3 parts by weight of the obtained sample was used to form a toner in the same manner as in Example 7. When the performance was evaluated, it was found to be a durable developer with excellent mold releasability and low capri.

Example-3 Low molecular weight polypropylene (molecular weight 6.o o o) J
001 Tonif Rosin Oil Platz/RX1001
were melted and dispersed in the same manner as in Example-7, and the obtained sample was
Using parts by weight, the developer was made into a toner and its performance was evaluated, and it was found to be a developer 1'' with excellent dead center and mold releasability and durability.

Example - xylene JO as a solvent in a zooct flask
Add OIt, warm to 710°C in an oil bath, then add 101% of low molecular weight polypropylene (molecular weight 4.000), stir for 30 minutes to dissolve, then add Nigrosine Oil Black EX (manufactured by Orient Chemical Co., Ltd.) sit. The mixture was stirred for 30 minutes to disperse, and then the xylene solvent was removed under vacuum.

Then, the sample was cooled and crushed to give 4 pieces of 1 itoti. Ta.

When 3 parts by weight of this sample was used in the same manner as in Example 1 to form a toner and evaluated, it was found to be a highly durable developer with excellent mold release properties and little capri.

Example-j Low molecular weight polypropylene (molecular weight t, o o o) was used, and triphenylmethane dye (R?-00-Orient Chemical Co., Ltd., the above formula ( 3 parts by weight of the sample obtained by melting and dispersing the toner using Osho) and evaluating its performance revealed that it is a highly durable developer with excellent mold release properties and low capri. Understood.

Example-6 Low molecular weight polypropylene (molecular weight 6.ooo) λooi
t and chromium-containing metal complex dye (Parifast φ31
Copying using a roll fixing method using 3 parts by weight of a sample obtained by melting and dispersing 1001 (manufactured by Orient Chemical Co., Ltd.) in the same manner as in Example-/, turning it into a toner and using a cadmium sulfide photoreceptor. After repeated evaluations, it was found to be a highly durable developer with excellent mold releasability and low Capri (D).

Example 7 Low molecular weight polypropylene (molecular weight 4.000) was used, and Nigrosine Oil Black EX (manufactured by Orient Chemical Co., Ltd.) was used as a charge imparting agent in the same manner as in Example 3. A melt-dispersed sample 3 weight-1 ( (manufactured by Mitsubishi Chemical Corporation) and 5 parts by weight of Nigrosine Oil Black Ex (manufactured by Orient Chemical Co., Ltd.) were melt-kneaded and]! The powder was crushed and classified to obtain a toner having an average particle size of ljμ. Add 4 parts by weight of this toner to 1so
- Key points for making 10,000 copies using a heat-pole fixing type copying machine with zinc oxide as a photoreceptor, by mixing 100 parts by weight of iron powder with a particle size of It was found that the developer produced copies with excellent thermothermal properties and less capri, and showed high durability.

Comparative example-l Styrenic resin (Bair 8BM-400-Sanyo Chemical)
100 parts by weight, low molecular weight polypropylene (molecular weight t, o
oo")s, 7 parts by weight of Nigrosin Oil Press EX (manufactured by Orient Chemical Co., Ltd.) as a charge imparting agent, and 7 parts by weight of Carbon Black Sim-l (1 ton by Mitsubishi Chemical Co., Ltd.) were melt-kneaded, crushed, classified, and averaged. 0 obtained toner with particle size l!μ
When I made copies using a heat roll fixing type copying machine using this flashing material, I found that the capri was bad from the beginning and even worse after 200 copies, and that the developer was not durable. .

Comparative Example - Comparative Example - Polyester resin N-3 instead of styrene resin! - Nippon Ester Co., Ltd.), and in the same way as Comparative Example 7, the key points on the back were also bad from the beginning.

After copying, I found that the capri was even worse and that the developer was not durable.

Sender: Mitsubishi Chemical Industries, Ltd. Representative Patent Attorney Hase - Others/names

Claims (1)

[Scope of Claims] (1) A toner for electrostatic charge development made by kneading a styrene resin and/or a polyester resin, a charge imparting agent, and a low molecular weight polytetrapyrene containing the charge imparting agent dispersed therein. (2) The molecular weight of low molecular weight polypropylene is 000~
Claim 0LjIAI which is J O,000! 1. The toner according to item 1. (3) The toner according to claim 1, wherein the charge imparting agent is a nigrosine dye. (4) The toner according to claim 1, wherein the charge imparting agent is a triphenylmethane dye. (6) The toner according to claim 1, wherein the charge imparting agent is a chromium-containing metal complex dye.