Konishiroku Photo Industry Co., Ltd.

Sekisui Chemical Co., Ltd.

Japan Synthetic Rubber Co., Ltd.

Goichi Yamakawa

Makoto Tomono

Takahira Kasuya

Hideaki Morita

Hiroyuki Takagiwa

Tsuneo Wada

Nobuo Takahashi

Isao Furuta

Shotaro Watanabe

Minoru Tsuneyoshi

Takeo Nishimura

Yoshihiko Hyosu

Shinichiro Yasuda

Minoru Kohara

Sadayasu Miyahara

Saburo Wakimoto

Hirozo Funaki

Keiji Sato

Mitsunori Ohta

Tetsumasa Ishida

Kenzi Thuzita

The present invention relates to toners for electrophotography wherein the main resin component comprises a lower molecular weight polymer and a higher molecular weight polymer each of which is different from the other wherein the higher molecular weight polymer has a glass transition point of at least 50.degree. C. and the lower molecular weight polymer has a glass transition point no higher than 65.degree. C. The above polymers comprise one or more polymers selected from styrene polymers, arcylic polymers, and styrene-acrylic copolymers. Generally, the lower molecular weight polymer has a weight average molecular weight of 50,000 or less and the higher molecular weight polymer has a weight average molecular weight of 80,000 or more.

Toner for electrophotography

The present invention relates to toners for developing electrostatically charged images which are comprised of a polyester binder resin condensed from diols of the formula ##STR1## with a polyhydric carboxylic acid or a derivative thereof wherein the polyhydric carboxylic acid is a mixture of dihyridic carboxylic acid or its alkylesters and about 30 mole % to about 80 mole % of the total acid content of more hydric carboxylic acids or therein hydrids.

Toner for developing an electrostatically charged image

Toner for developing electrostatically charged images comprising nuclear particles formed by polymerization, hydrophobic silica, and a resin, wherein said resin is coated on said nuclear particles and said silica is dispersed in said resin. A method for producing said toner is also disclosed, said method comprising polymerizing nuclear particles, dissolving a resin in a solvent, which asserts a lesser solvating action against said nuclear particles than against said resin, to form a solution, dispersing said hydrophobic silica in said solution, mixing said nuclear particles with said dispersion, and drying said mixture.

Triboelectric stabilized toner for developing electrically charged

There are disclosed an electrostatic image developer which comprises a carrier comprising iron powder particles coated with a resin and a toner comprising a low molecular weight polypropylene, and an electrostatic image developer which further comprises as binder a homopolymer of a styrene or a copolymer of a styrene with an another vinyl monomer containing 10 to 70% by weight of a high molecular component having a molecular weight of 100,000 to 10,000,000. The electrostatic image developer of the present invention can accomplish good developing without forming fogging even when provided in a great number of developments, thus exhibiting a great durability, and is also free from image contamination by the off-set phenomenon to give an excellent copied image.

Developer composition for developing an electrostatic image

An electrostatic image developing toner comprises a binder resin which contains at least 60% by weight of a styrene-butadiene copolymer. The copolymer contains a component A having a molecular weight of at least 100,000 in an amount of at least 20% by weight relative to the binder resin, and a component B having a molecular weight of at least 500,000 in the component A is not more than 15% by weight relative to the binder resin. The toner has adequate flowability and noncoagulation property and is capable of forming a superior visible image in a contact heat fixing system.

Electrostatic image forming toner

An iron powder developer carrier for electrophotography having at least the outer surface thereof coated with iron oxide. The iron oxide has a particle size of 50 to 200.mu., an apparent density of 1.5 to 2.5 g/cm.sup.3 and a specific surface area of 0.01 to 0.3 m.sup.2 /g. A process for the preparation of iron powder developer carriers for electrophotography, which comprises the steps of subjecting a starting iron powder to a primary calcination treatment in an inert gas atmosphere without using a binder, pulverizing and classifying said calcination product to prepare an intermediate iron powder, reducing the intermediate iron powder in a reducing atmosphere and washing the intermediate iron powder, and subjecting the intermediate iron powder to an oxidizing calcination treatment.

Developing material for electrophotography, process for preparation

A method for manufacturing a toner for use in electrophotography comprising polymerizing a monomer to provide the polymer constituent of the toner in the presence of both a coloring agent and an anti-offset agent. Specific anti-offset agents are set forth and the toner made by the foregoing process is also disclosed.

Method for manufacturing toner for electrophotography

A toner for developing an electrostatic latent image comprising a resin prepared by emulsion polymerization of a first polymer to yield a first emulsion, emulsion polymerization of a second polymer to yield a second emulsion, mixing said first and second emulsions and coagulating said mixture, wherein said second polymer has characteristics different from those of said first polymer.

Toner for developing of electrostatic latent image

An iron powder developing carrier for developing an electrostatic latent image, a manufacturing method thereof, a developer containing said developing carrier and a method of forming a visible image by using said developer. Said iron powder developing carrier has the apparent density from 1.5 to 2.5. Said manufacturing method comprises the steps of sintering a raw iron powder having been ground to particles of not larger than 50 microns in diameter without using any binder agent at the temperature from 900.degree. to 1200.degree. C. to form an sintered body, grinding and classifying said sintered body into an intermediate iron powder having the particle diameter from 50 to 200 microns, then treating said intermediate iron powder to oxidize at the temperature from 280.degree. to 390.degree. C., and adjusting the resultant iron powder so as to have the apparent density from 1.5 to 2.5.

Iron powder developing carrier and the manufacturing method of the same,

According to the present invention, there is provided a toner for developing electrostatic latent images, which includes a colorant, an amine-addition resin and, if desired, the resin miscible with the amine-addition resin. The above mentioned amine-addition resin is further obtained by interacting an epoxy group-containing resin and an aliphatic primary or secondary amine.

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Hachioji, Japan

Goichi Yamakawa