Minolta Camera Kabushiki Kaisha

Minolta Company, Ltd.

Toshitaro Kohri

Junji Machida

Hitoshi Kato

Masahiro Anno

Eiichi Sano

Junji Ohtani

Hiroyuki Fukuda

Akihiro Nakamura

Yoshimasa Nishihara

Mitsutoshi Nakamura

Ichiro Demizu

Makoto Kobayashi

Noboru Ito

Yukio Tanigami

Kunio Takahashi

A method for manufacturing an electrophotographic toner having a mean particle diameter of more than 5 &mgr;m and less than 10 &mgr;m. For manufacturing the above size of toner, coarsely pulverized particles are pulverized to medium pulverized particles having a mean particle diameter of more than 10 &mgr;m and not more than 19 &mgr;m at first. Subsequently, the medium pulverized particles are further pulverized to small diameter particles having a mean particle diameter of more than 5 &mgr;m and less than 10 &mgr;m, and thereafter the small diameter particles are classified by a rotor type classifier.

Method for manufacturing an electrophotographic toner

This invention provides a two-component developer comprising magnetic carrier particles and toner particles which contain magnetic particles at a specified content, being excellent in high speed copying system.

Two component developer comprising specific magnetic toner and specific magnetic carrier

Two-component developer comprising specific magnetic toner and specific

The present invention related to a toner for electrophotography comprising at least a binder resin, a coloring agent and a wax for off-set prevention, in which the wax is incompatible with the resin, dispersed insularly in the resin in the form of substantially spherical and/or substantially spindle-shaped particles, the number of spindle-shaped wax-particles occupying 70% or less of the total number of wax-particles. The spherical wax-particles have a following relationship between a mean wax-particle size (Dw) and a mean toner-particle size (Dt):

Toner for electrophotography containing wax-particles dispersed in

The present invention relates to a color toner, to the surface of which a small amount of charge-giving agent is fixed. The amount of the charge-giving agent is usually 0.03% to 0.65% by weight of toner, and it becomes still smaller when the resin composing the toner is made from a monomer including a nitrogen containing polar functional group or fluorine containing polar functional group. This composition enables the toner to be charged stably in a narrow charge distribution, thereby decreasing the fog and flying of toner, and resulting in a distinct color image without any turbidity in color.

Color toner for developing electrostatic latent image

The invention relates to a toner for developing electrostatic latent images for use in copying machines and including a thermoplastic resin and a black coloring material as main components. The black coloring material comprises a substantially non-magnetic inorganic black pigment of 5-25 cc/100 g oil absorption and 0.5-10 .mu.m average particle diameter, to obtain high quality copy images having fine textures.

Toner for developing electrostatic latent images

The present invention provides a developer for developing electrostatic latent image which comprises capsule toners and carriers; said capsule toner having many wrinkles or hollows and upheavals and containing liquid in a shell, and the carriers have no sharp edge or a lower specific gravity, the image copied by the developer can be fixed by pressure under low temperature.

Electrostatic latent image developer comprising capsule toner of

The present invention provides a capsule toner having many wrinkles or hollows and upheavals and containing liquid in a shell, which is useful for toner for pressure fixation.

Wrinkle configured electrophotographic capsule toner particles

This invention provides white toners for use in forming images by dry process comprising titanium dioxide with 0.20-0.35 .mu.m in mean particle size. White toners of the invention are excellent in hiding properties and have no problem about toner flying, fogs and so on.

White toner comprising titanium oxide of specified size

The present invention relates binder type carriers, the surface of which is firmly adhered with charge controlling agents, by which the elastic charge of the carriers can be controlled to a desirable polarity and a level without the influence of the chargeability inherent to the magnetic powders themselves.

Binder type carrier

The invention relates to binder type carrier comprising at least magnetic particles and binder resin having an acid value of 50 mg KOH/g or less and a hydroxyl value of 50 mg KOH/g or less, in which a product of the acid value by the hydroxyl value is within the range of from 1 to 600, which gives a high specific volume resistance of equal or more than 10.sup.13 .OMEGA.cm, and an excellent humidity resistance.

Binder-type carrier

The invention relates to binder type carriers comprising at least magnetic particles and binder resin, characterized by that the binder resin has the characteristics of;

Binder-type carrier suitable for a developing method of electrostatic

The present invention provides a carrier coated by a polymer particle layer containing fine magnetic particles around a magnetic core, which may contain an electrical charge controlling agent, and the core may be pre-treated with a coupling reagent; the carrier gives excellent clearness to the copy and durability at repeating use.

Carrier for use in developing device of electrostatic latent image and

A dry developer for developing electrostatic latent images comprises a positive charge type carrier and a negative charge type toner. The negative charge type toner includes, as after-treating agents, fine particles of hydrophobic silica in an amount of 0.05-1.0 percent by weight relative to the toner and fine particles of hydrophobic titanium oxide in an amount of 0.1-3.0 percent by weight relative to the toner, the fine particles of hydrophobic silica and the fine particles of hydrophobic titanium oxide being contained in a weight ratio of 1:5 to 1:1.

Dry developer for developing electrostatic latent images contains silica

A developer for use in developing an electrostatic latent image according to electrography comprises a mixture of a carrier and a toner having a property of being triboelectrically charged to a positive polarity when held in frictional contact with the carrier. The toner includes a binders which is a thermoplastic resin having a Lewis acid-functional group.

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Higashiosaka, Japan

Toshitaro Kohri