Kabushiki Kaisha Toshiba

Kabushiki Kaisha Tec

Shindengen Electric Manufacturing Company Limited

Yamanashi Electronics Co., Ltd.

Seiji Arai

Michihisa Iguchi

Tetsuya Nakamura

Takahito Kabai

Satoshi Katagata

Chinobu Sakai

Hiroshi Hashizume

Hirotaka Fukuyama

Yoshiaki Okano

Kouichirou Satou

Masaaki Ishikawa

Takashi Ishikawa

Koichiro Sato

Toshio Takagi

Yasuo Fujii

Shuji Nishina

Masatoshi Maruta

Seiichi Koizumi

Jiro Hukasawa

An electrophotographic recording apparatus including a photosensitive drum, a charging section, an exposure section, a developing section, and a transfer section. The charging section is used for recharging the photosensitive drum. In the electrophotographic recording apparatus, the photosensitive drum is recharged after a developed image is transferred to a transfer sheet. Thus, after the transfer section is stopped, the charging and developing sections remain active for at least a rotation of the photosensitive drum. Accordingly, the electric voltage level of the photosensitive drum is uniform.

Electrophotographic recording apparatus

At start of rotation of a photosensitive drum, rotation of a developing roller caused by a developing/register rollers driver is kept stopped until a time required for a predetermined point on the photosensitive member, which was located at a charging position when charging thereof by a charging device was started, to reach a development position elapses, and thereafter the developing roller is rotated by the developing/register rollers driver. When the predetermined point on the photosensitive member, which was located at the developing position when at least rotation of the photosensitive member was started, passes the transfer position, a roller cleaning voltage having the same polarity as the charge polarity of toner is applied to a transfer roller.

Electrophotographic apparatus that prevents toner from attaching to a

A developing device used in an electrophotographic apparatus has seal members fixedly disposed between both end portions of a developing roller and those portions of inner walls of a device casing which correspond to both end portions of the developing roller. The seal members are made of a material which can be charged by friction with the developing roller to have the same polarity as charged toner. The toner is blocked by the seal members and presented from entering end portions of the developing roller.

Electrophotographic apparatus having cleaning device and developing

An electrophotographic apparatus including an electrically conductive brush roller for recovering and discharging a residual toner which is located in contact with a photoreceptor drum. A positive voltage is applied to a transfer roller, whereupon the toner is charged positively. As a recording region on the photoreceptor drum with an electrostatic latent image formed thereon passes the brush roller, a voltage of a potential lower than the potential of the recording region is applied to the brush roller, and the brush roller recovers the residual toner. As a non-recording region on the photoreceptor drum without the latent image thereon passes the brush roller, on the other hand, a voltage of a potential higher than the potential of the non-recording region is applied to the brush roller, and the recovered toner is discharged onto the non-recording region. The discharged toner is returned to a developing roller after a charging process.

Electrophotographic apparatus capable of preventing image deterioration

In a developing device for developing an electrostatic latent image formed on a photosensitive member in an electrophotographic apparatus, a developing roller and a developing blade are formed such that the hardness of the surface of the developing blade is higher than the hardness of the surface of the developing roller by 30 degrees or more in JIS-A hardness. The developing blade deforms and bites into the developing roller. Accordingly, the developing roller can be brought into tight contact with the developing blade, and a great frictional force is applied to the toner passing between the developing roller and blade to fully charge the toner.

Developing device for electrophotographic apparatus

A transfer device of a contact transfer method wherein a transfer power supply applies a predetermined transfer voltage to a transfer roller contacting the rear surface of a printing sheet, so that an electric field for causing the toner to be attracted by the transfer roller is generated. A lumped constant resistor is electrically inserted between the transfer roller and the transfer power supply. The lumped constant resistor has an electric resistance smaller than an equivalent electric resistance obtained when the whole transfer roller is regarded as one electric resistor. When the electric resistance of the printing sheet changes in accordance with a change in ambient environment, the voltage drop across the lumped constant resistor is changed to compensate for the change in electric resistance of the printing sheet.

Transfer roller and toner for electrophotographic apparatus

An image forming apparatus includes a distributing device for distributing residual toner remaining on a photosensitive member after a developed toner image is transferred to a sheet-like paper and before a subsequent image is formed. The distributing device includes a distributing brush which is located between a transferring device and a charging device, has a contact portion contacting the photosensitive member, and includes a voltage supply device for supplying a direct current voltage to the distributing brush. The voltage difference between the distributing brush and the photosensitive member is sufficient to cause a discharge to occur between the distributing brush and photosensitive member.

Image forming apparatus

A developing device used in an electrophotographic apparatus has seal members fixedly disposed between both end portions of a developing roller and those portions of inner walls of a device casing which correspond to both end portions of the developing roller. The seal members are made of a material which can be charged by friction with the developing roller to have the same polarity as charged toner. The toner is blocked by the seal members and prevented from entering end portions of the developing roller.

Electrophotographic apparatus having developing device with seals for

In an electrophotographic device, a main body is divided into a lower body and a swingable upper body. A process unit formed of at least a toner holder, a charger, and a developer is detachably mounted in the lower body. The position of the process unit (particularly, the photosensitive member) relative to the lower body (particularly, a member driving gear) is controlled by placing a shaft of the member through a groove in a side wall of the lower body at one end of the member, and by bringing a lower end of the side wall of the process unit supporting the member into contact with an upper end of a support member supporting the member driving gear. An exposure unit mounted in the upper body is positioned to the photosensitive member with a predetermined distance therebetween by bringing a contact portion of the exposure head into contact with the side wall of the lower body supporting the member.

Detachable process unit for an electrophotographic device

A developing device includes an agitator rotated in a toner hopper. The agitator has a rod portion. A first coil spring portion is wound around the first portion of the rod portion in a first direction. A second coil spring portion is wound around the second portion of the rod portion in a second direction. The first direction is opposite to the second direction.

Developing device and image forming apparatus including an agitator

A toner pack for use in an electrophotographic apparatus is formed of a polypropylene resin containing 30 to 50 wt % calcium carbonate filler. This resin has a high deformability, and generates a small amount of heat at the time of incineration thereof. Thus, the used toner pack can be disposed of together with flammable products made of paper and/or wood. Further, at the time of disposal, it is possible to fold the used toner pack to reduce its size.

Toner pack and development device for use in electrophotographic

A developing apparatus including a hopper storing toner and carrier and a roller disposed in an opening of the hopper. A carrier stopper is provided on a front wall of the hopper proximate the opening having an arced surface concentrically opposing an upper portion of the roller. Thus, a blend layer volume is formed in a first space between the carrier stopper and the roller for storing a blended layer of carrier and toner such that the carrier stopper prevents carrier from scattering outside the blend layer volume and the conjunctional effect of rotating the roller and of the magnetic force of the rotary magnets in the roller blends the carrier and toner stored in the blended layer. A sub-hopper, proximate the blend layer volume, is also formed by a second space between the carrier stopper and a lateral bottom wall of the hopper for storing toner to be provided to the blended layer.

Developing apparatus

A laser generating apparatus inputs to a laser scanner as modulating data a signal indicative of the logical sum of serial data corresponding to image information and an arbitrarily delayed version of the serial data. Thus the laser scanner modulates the laser beam in accordance with on and off intervals of the modulating data and irradiates the modulated beam onto a photosensitive body to scan the same. Therefore, changes in the laser exposure width due to fluctuations of the surface potential (mainly, the exposure potential) of the photosensitive body are easily and certainly corrected in accordance with the adjustment of the on and off intervals of the modulating data, namely, the adjustment of the quantity of data delay.

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Tokyo, Japan

Seiji Arai