Sharp Kabushiki Kaisha Corporation

Takahiro Bito

Tatsuo Imafuku

Hitoshi Nagahama

Toshihisa Ishida

Takeshi Satoh

Junichi Saito

Yoshinori Urata

Tadashi Nakamura

Nobuyasu Honda

Yasuharu Morinishi

Kazuki Takatsuka

Keizo Kitamura

Takeshi Kato

Satoshi Ogawa

Yoshiaki Akazawa

Syouichi Fujita

Tadayuki Sawai

Kouichi Takenouchi

Katsuaki Sumida

Teruhiko Noguchi

Takeshi Ohkawa

Ken Yamagishi

Yukihisa Imaue

Eiji Tenjiku

Toru Nishikawa

Masaki Ueji

Tenjiku Eiji

Ohkawa Takeshi

Akiko Tsujimoto

Tatsuya Itou

The present invention provides a carrier for a two-component electrophotographic developer, comprising a core particle and a thermoset silicone resin layer coated thereon, wherein said layer comprises a charge control agent and is formed by heat-treatment at a temperature below the melting point of said charge control agent.

Carrier, two-component developer using the same, and image-forming apparatus using said developer

An image forming apparatus of the present invention is an image forming apparatus into which a memory device is insertable and which performs a printing process on an image of image data stored in the memory device. The image forming apparatus includes a memory reading section for detecting insertion of the memory device into the image forming apparatus, and a display processing section for performing a notification process of warning of accidental ingestion of the memory device, when the memory reading section detects the insertion of the memory device. This makes it more surely possible to cause a user to give attention to accidental ingestion by young children.

Image forming apparatus, image forming system, storage medium, and control method including recommendation information writing

The toner transporting section is provided with a plurality of toner discharge portions, selectively discharges a waste toner from any one of the plurality of toner discharge portions, and stores the waste toner in a waste toner container to which the waste toner discharged from the selected toner discharge portion is to be stored. Accordingly, it is possible to exchange the waste toner container corresponding to the toner discharge portion not used for discharging the waste toner. Therefore, it is possible to exchange the waste toner containers without stopping an image forming operation in an image forming apparatus provided with a cleaning device.

Developer recovering device and image forming apparatus having the same

A toner comprising a small-particle diameter external additive having a number average particle diameter of 7 to 20 nm, a large-particle diameter external additive having a number average particle diameter of 40 to 80 nm and a toner particle having a volume average particle diameter of 4 to 7 &#x3bc;m, wherein the large-particle diameter external additive is stuck to the surface of the toner particles in a semi-embedded state and has a rate of liberation of 0.1% by weight or less from the surface of the toner particle.

Toner, two-component developer and image formation device

Provided is a developing toner for electrostatic latent images capable of coping with the size reduction of an image forming apparatus and decrease of the consumption amount, not shortening the working life of a photoreceptor, less causing paper jam, background fogging, etc., excellent in various characteristics required for the toner, and capable of forming images of good picture quality. The developing toner being used when images are formed to a recording material in an image forming apparatus comprising an image forming station, a recording material feeding station, an image fixing station and a controlling station, the developing toner for electrostatic latent images containing hydrophobic fluidizing particles deposited to the surface of coloring resin particles comprising a binder resin containing a polyester resin, a polyalkylene, a polyolefin dispersant and a non-oxidized polyethylene resin, and an inorganic pigment, and having time constant &#x3c4; of from 100 to 350 msec.

Developing toner for electrostatic latent images, imaging forming method and image forming apparatus

A toner for electrostatic image development, which contains toner particles in which not more than 13 percent by number of the toner particles have a particle diameter of smaller than 4 &#x3bc;m, not less than 20 percent by number of the toner particles have a particle diameter of 4 &#x3bc;m to 6 &#x3bc;m, and not more than 2.0 percent by volume of the toner particles have a particle diameter of 16 &#x3bc;m or greater. The toner particles have a volume average diameter of 4 &#x3bc;m to 9 &#x3bc;m, and at least an external additive is added to the toner particles.

Toner for electrostatic image development and image forming method using the same

In the two-component developer for use in electrophotography containing a toner and a carrier, said toner contains a magnetic powder as an external additive, said carrier is a resin coated magnetic carrier of 6.0 to 8.0 in true specific gravity, and the coating resin is a silicone based resin containing a crosslinking agent having phenyl groups and an aminosilane coupling agent. The crossliking agent in the coating resin for the carrier has phenyl groups in a content ratio of 0.2 to 15% by number.

Developer for use in electrophotography and method and apparatus for image formation

The present invention provides an electrophotographic developer which reduces toner contamination on the surface of a developer carrier even when a development effective range is narrowed and which is stabilized in an image quality in every environmental situation and has a long life and a low cost and an image-forming method using the same. In the present invention, used for the electrostatically charged-image holder described above having a radius of curvature of 18 mm or less in a development effective range is the electrophotographic developer which is a two-component developer comprising a toner comprising at least a binder and a colorant and a carrier which is coated with a resin and has a weight average particle diameter of 40 to 100 &#x3bc;m, wherein the above toner has a volume average particle diameter of 8 to 11.5 &#x3bc;m, and the toner particles having a diameter of 6.35 &#x3bc;m or less account for 20 number % or less.

Electrophotographic developer and image-forming method using the developer

A magnetic member is arranged at a position on the downstream side with respect to the rotational direction of a developing sleeve, outside the developer conveyance path where the magnetism from the magnetic member has no influence on the magnetic field of the developing magnetic pole. When the magnetic member is arranged with its N pole facing the developing sleeve, the magnetic attractive force from the magnetic member weakens the developer's attraction to the peripheral surface of the developing sleeve. When the magnetic member is arranged with its S pole facing the developing sleeve, the developer being conveyed along the developer conveyance path is magnetized in such a direction as to repel the peripheral surface of the developing sleeve. In either case, the adhering state of the developer to the peripheral surface of the developing sleeve having passed through the developing position is unstable, so that the developer having adhered to the developing sleeve will easily drop off from the developing sleeve after passage of the developing position.

Electrophotographic developing unit

A binder resin as the main component of the toner has a low molecular weight polypropylene as a separating agent, encapsulated therein. Using this binder a toner with the wax having a diameter of 0.3 .mu.m or less dispersed therein is produced. The wax is included 0.5 part to 5 parts by weight for 100 parts by weight of the binder resin. This limitation of the toner prevents the setoff phenomenon during the fixing process and at the same time prevents the filming phenomenon over the photoreceptor and achieves an improved fixing performance.

Toner for electrophotography and a production method thereof

A toner for electrophotography includes a binder resin as the main component and a coloring agent, wherein the binder resin contains a low molecular weight polypropylene as a separating agent, encapsulated therein; the acid value of the binder resin is adjusted equal to 1.0 (mgKOH/g) or below; and the coloring agent has a surface which is not oxidation treated and presents a pH of 7.0 or higher. Limiting the added amount and the diameter of encapsulated and dispersed polypropylene wax provides prevention against both the setoff and filming phenomena.

Toner for electrophotography

A process for preparing a toner includes forming a melt-kneaded mixture by mixing a raw material mixture containing a quaternary ammonium salt compound at a temperature ranging from (M-7).degree. C. to (M+7).degree. C., where M is a melting point of the quaternary ammonium salt compound, with a kneading device having a discharge port whose temperature is set lower than a temperature at which a melt viscosity of the melt-kneaded mixture at the discharge port is not higher than 10,000 Pa.a, removing the melt-kneaded mixture from the kneading device, rolling out the melt-kneaded mixture to a thickness ranging from 1.2 mm to 3.0 mm, and cooling down the melt-kneaded mixture. With the use of the toner produced by this process, the amount of charge during copying is retained in an appropriate range irrespectively of the working atmosphere and conditions of use, thereby maintaining a good image density.

Toner, Developer, and process for producing the same

A photosensitive element is produced with a minimum amount of a conductive synthetic resin material. A draft for injection molding is formed in the inner circumferential surface as a supporting body, and a driven member provided with a gear is fixed to the end of the supporting body with a smaller inner diameter, that is, the thicker end. A driven portion in which a plurality of projections and depressions are formed alternately to be adjacent to each other in the circumferential direction is arranged on an axial end of a cylindrical supporting body made of a conductive synthetic resin, including a photosensitive layer on the outer circumferential surface. By a joint member removably engaged with the driven portion, the supporting body is rotated around the axis. In one arrangement, only the end of the supporting body is solid. In another arrangement, the supporting body is solid in the almost entire length in the axial direction.

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Nara, Japan

Takahiro Bito