JPS5880650A - Magnetic toner - Google Patents

Abstract

PURPOSE:To obtain a magnetic toner having a tough coating and showing improved fluidity by coating a magnetic body with a room temperature curing dimethyl polysiloxane polymer. CONSTITUTION:To a magnetic toner is added a magnetic body coated with 3-30pts. room temperature curing dimethylpolysiloxane polymer basing on 100 parts magnetic body.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic toner used for developing electric or magnetic latent particles in electrophotography or electrostatic printing. It is known that 1
, generally utilizes a photoconductive substance to form an electrical latent image on a photoreceptor by various means, and then develops the image with toner and, if necessary, transfers it to a paper 1 transfer material. A copy is obtained by fixing the transferred toner image using heat, pressure, solvent vapor, etc. Various developing methods are also known in which an electrical latent image is visualized using toner.

For example, the magnetic brush method described in US Patent No. 2874063, the cascade development method described in US Patent No. 2618552, and US Patent No. 22.
A number of development methods are known, such as the powder development method, fur brush development method, and liquid development method described in No. 21776.

Conventionally, fine powder in which dyes and pigments are dispersed in natural heat or synthetic resin has been used. Furthermore, it is also known to use fine developing powder to which a third substance is added for various purposes.

The developed toner image is transferred and fixed onto a transfer material such as paper, if necessary. Methods for fixing toner images include a method in which the toner is heated and melted using a heater or a heated roller, etc., and fused and solidified to the support; a method in which the binder resin of the toner is softened or dissolved with an organic solvent and then fixed to the support. A method of fixing a toner to a support (by applying pressure) is known.

Toner materials are selected to suit each fixing method,
Toners used in a particular fusing method generally cannot be used in other fusing methods.

In particular, the toner used in the conventionally widely used heat fusion fixing method using a heater is fixed using a heated roller constant fixing method, a solvent fixing method, and a solvent fixing method.
It is almost impossible to apply it to pressure fixing methods, etc.6.
Therefore, toners suitable for each fixing method are being researched and developed.

A method has been used in which an electrostatic latent image is developed using a one-component developer that contains magnetic particles and does not use carrier particles, but in this case, the toner binding I/Ii fat is mixed with magnetic fine particles. Dispersibility, adhesion, impact resistance, fluidity, etc. of the toner are required.

In addition, when the 3J is applied due to the frictional electrification between this -component developing agent and the developing sleeve roller, the insulating material separates due to impact or use over time, and adheres to and accumulates on the sleeve roller due to the tribo effect. However, there are still problems with the -ingredient dehydrating agent, such as the possibility of poor durability.

The present invention provides a magnetic toner that solves the above-mentioned drawbacks.

A further object of the present invention is to provide a magnetic toner in which the magnetic material has good dispersibility and adhesion to the binder resin of the toner.

Another object of the present invention is to improve the fluidity of magnetic toner.

The present invention provides a magnetic toner with good triboelectric charging properties.

A further object of the present invention is to provide a magnetic toner with good environmental stability.

That is, the present invention completely eliminates the above-mentioned drawbacks of magnetic toner by coating the magnetic material with a room temperature-curable dimethylpolysiloxane polymer.

Room-temperature-curable dimethylpolysiloxane polymer is a so-called silicone resin, but because it is room-temperature-curable, the coating is strong and has good fluidity.Further features of the present invention The triboelectric properties of the cured material of this dimethylpolysiloxane polymer positively charge the iron powder and can be used to develop a negative electrostatic latent image.

Moreover, since the surface of the magnetic material itself is hydrophilic, its frictional charging properties may become unstable in the environment, especially in high humidity, but the material of the present invention, which does not become damp, has good environmental stability. Another feature is that it becomes

The coating amount of the room temperature-curable dimethylpolysiloxane polymer magnetic material is preferably 3 to 30 seconds (preferably 5 to 25 parts) per 100 parts of the magnetic material. If it is less than 3 parts, there will be no good effect on separation properties, adhesion, environmental stability, etc. to the binder.
If the amount is 0 parts or more, adsorption to the magnetic material becomes excessive and adhesion to the magnetic material becomes poor.

The magnetic material may be any material that exhibits magnetism or can be magnetized, such as iron, manganese, gold such as nickel, cobalt, and chromium, magnetite, hematite, ferrite, manganese alloys, and other ferromagnetic alloys. There is,
The average particle size of these particles is approximately 0.05 to 5μ (more preferably 0
．． A fine powder of 1 to 2μ) can be used. ima
*Fi% of the magnetic material contained in the toner
15 to 70 of the total weight of the rice cake (more preferably 25 to 70)
45 weight IJ6) is good.

All known binder resins can be used for the toner, including styrene and its substituted 6 monopolymers such as polystyrene, boriz P-cool styrene, and polyvinyltoluene, and styrene-P-chlorostyrene co-X polymers. , styrene, -propylene copolymer, styrene/-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene/butyl acrylate copolymer, styrene-acrylic ethyl copolymer, styrene-acrylic Butyl acid co-electropolymer, styrene-octyl acrylate copolymer, styrene-methacrylic iron-methyl co-makura body, styrene-ethyl methacrylate copolymer, styrene/-butyl methacrylate copolymer, styrene-α Methyl chlormethacrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether [[coupled], styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer , styrenic copolymers such as styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer, sterebe-maleic acid copolymer, styrene-maleic acid ester copolymer, polymethyl methacrylate, polybutyl methacrylate, poly Vinyl chloride, polyvinyl acetate, polyethylene/, polypropylene, polyester,
Polyurethane, polyamide, EBOKI 7 resin, polyvinyl butyral, polyamide, polyacrylic acid resin, rosin, modified rosin, terpene resin, phenolic resin, y
UfI aliphatic or alicyclic hydrocarbon resin, aromatic petroleum resin, chlorinated paraffin.

Paraffin wax and the like can be used alone or in combination. Furthermore, the toner used in the present invention includes toned colors,
Various dyes and pigments such as carbon black may be contained for the purpose of charge control and the like.

Examples of the present invention will be described below. Parts are parts by weight.

[Example 1] It was left to dry for 3 days.

Occasionally, the powder was rolled to avoid aggregation of the a-type powders, and the powder was crushed using a small pulverizer (Emide type, manufactured by Shida Rikagaku Co., Ltd.) or with fingers, and then hardened.

Next, a developer was prepared using the following formulation.

The above mixture was kneaded, cooled, pulverized, and classified to obtain a toner. Next, 1 t of silica (TEPSIL ER manufactured by Nippon Silikani Co., Ltd.) was externally added to 100 f of this toner to obtain a developer. In a high temperature and high humidity atmosphere of RH, the developer is put into the developing device and applied with AC bias (number 12
00 Hz VPP 1200 V DC-200 V) was applied to develop the negative electrolyte image. As a result, the UHIa degree was 1.24. As a comparative example, the dimethylpolysiloxa of Example 1 was obtained.

After processing in the same manner as in Example 1 using a magnetic material that was not coated with a combination of tums and tested in the same atmosphere, the maximum image density was 0.53 and the image was unclear.

[Example 2] A test was conducted in the same manner as in Example 1 except that the 5R-2410 in Example 1 was replaced with SR-240650 in xt K. A maximum image density of 1.32 was obtained. friend.

[Example 3] A test was conducted in the same manner as in Example 1 except that 5R-2410 in Example 1 was replaced with 5it-2411, and a maximum -gI strain rate of 1.28 was obtained.

Applicant: Gyanon Co., Ltd.

Claims (1)

[Claims] Magnetic toner 0 characterized by containing a magnetic material treated with a room temperature curable dimethylpolysiloxane polymer.