Hitachi, Ltd.

Hitachi Koki Co., Ltd.

Ricoh Printing Systems, Ltd.

Hitachi, Ltd. and Hitachi Koki Co., Ltd.

Hitachi Koko Ltd.

Masaru Nakano

Akira Sasaki

Kazuhiro Wakamatsu

Junichi Matsuno

Kenji Mori

Masashi Yamamoto

Akira Shimada

Toru Miyasaka

Kazuo Kikuchi

Masahiko Saito

Toshio Ogiso

Hiroyuki Tadokoro

Chikara Hiraoka

Shogo Matsumoto

Tetsuro Akasaki

Hiromitsu Fukuda

Shoji Ukei

Katsuyoshi Onose

Akira Shimizu

Takeshi Kato

Isamu Terashima

Shunichi Oohara

Shigeru Obata

Katsumi Kumada

Toru Hanashima

Masafumi Suzaki

Atsushi Onose

Katsumasa Mikami

Kazushige Oonishi

Michio Sumiyoshi

Tomio Hayano

Toru Ohashi

Tsuyoshi Koyama

Takashi Kakuhashi

Hitoshi Furuyama

An image forming and recording apparatus, having a fixing apparatus for fixing unfixed toner image on a recording medium, wherein the fixing apparatus includes a fixing roller integrating a heater therein, an endless belt wound around the fixing roller, and three pressure members for pressing the endless belt onto the fixing roller. A pressure member located nearest to a side of entry of paper among the three pressure members is made up with a non-rotary type pressure member, and other two pressure members are made up with either one of a rotary type pressure member and the non-rotary type pressure member.

Image forming and recording apparatus with three pressure members

A picture image forming apparatus including a photoreceptor belt driven by a drive device, a plurality of developing devices for forming toner picture images on the photoreceptor belt, an intermediate transfer device, to a surface of which toner picture images on the photoreceptor belt are overlappingly transferred plural times when a picture image is to be formed on a single page, and a transfer roller for pushing a sheet against the intermediate transfer device in order to transfer toner picture images to the sheet. The intermediate transfer device is an intermediate transfer belt contacted by the photoreceptor belt to be driven thereby. A photoreceptor-side roller enables contact of the intermediate transfer belt and the photoreceptor belt, and the intermediate transfer belt is trained around the photoreceptor-side roller and a transfer-side roller for pushing the sheet against the transfer roller. A diameter d2 of the transfer-side roller is smaller than a diameter d1 of the photoreceptor-side roller.

Picture image forming apparatus with intermediate transfer belt trained around two rollers of different diameter

An image forming system including multiple photoconductors arranged in a line extending in a vertical direction and forming one body as one unit, and multiple development devices and multiple exposure devices arranged on one side of the line of the multiple photoconductors. An image is transferred to a recording medium on an other side of the line of the multiple photoconductors.

Photoconductor unit and image forming system

An image forming system having multiple photoconductors arranged in a line and forming one body as one unit, multiple development devices and multiple exposure devices arranged on one side of the line of the multiple photoconductors, an intermediate transfer device arranged on the other side of the line of the multiple photoconductors and a form cassette arranged below the line of the multiple photoconductors. The image forming system further includes a transfer device and a fusing device arranged at an opposite side of the intermediate transfer device with respect to the line of the multiple photoconductors.

A fixing device in an image formation apparatus has a heating roller and a backup roller. These rollers are each coated with single silicone rubber layers around the respective peripheries of their core bars. This silicone rubber has a volume resistance value of 10 &OHgr;&middot;cm or more. The heating roller is charged with electricity of the same polarity as the polarity of toner particles due to frictional electrification caused at the time of feeding of a recording medium. The heating and the backup roller are polarized reverse to the polarity of the recording medium. A quantity of charged electricity on the backup roller is made larger than that on the heating roller. This permits the image formation apparatus to prevent offset from occurring at the time of fixing a toner image onto the recording medium to cope with various types of recording media.

Fixing device improved in offset-prevention

In order to provide an image forming system characterized by compact configuration, high speed printing, high picture quality recording and excellent maintainability without image misregistration, an image forming system is provided, wherein multiple photoconductors are arranged along one of the surfaces of the intermediate transfer belt which is elongated in the longitudinal direction, and a fusing device is located on the other surface, with the photoconductors being integrated in one unit.

An electrophotographic apparatus comprising: a housing; a photosensitive member electrified by an electrification device; an exposure device for forming an electrostatic latent image onto the photosensitive member; a developing device for forming a toner image onto the photosensitive member; an intermediate transfer body to which the toner image is to be transferred; a transfer device for transferring the toner image formed on the intermediate transfer body onto a paper; a fixing device for heating the toner image on the paper; device for ejecting the paper outside the housing; device for exhausting the heat derived from the fixing device outside the housing; a cover provided on an upper portion of the fixing device; and an airflow path extending in a longitudinal direction of the fixing device and being provided by the cover and the housing, wherein the heat exhausting device is provided in an end portion of the airflow path.

Electrophotographic apparatus having heat exhaustion device

Registration controlling methods are provided for a color electrophotographic apparatus capable of forming an image without color registration errors and uneven color. This is accomplished by preventing a photosensitive medium from being undesirably moved in the direction perpendicular to the transportation direction caused by an electrostatic attractive force between the photosensitive medium and an intermediate transfer device, even if there is a twist between the fixed axis of the member supporting the photosensitive medium and the axis of the member supporting the intermediate transfer device. With these methods, a fur brush cleaner made of a conductive brush is detached from the intermediate transfer device during the time period after the start of driving the photosensitive medium and until the front edge of the photosensitive medium reaches the intermediate transfer device. A small amount of toner therefore always exists between the intermediate transfer device and the photosensitive medium during the transportation of the photosensitive medium, thereby reducing the electrostatic attractive force between the intermediate transfer device and the photosensitive medium and preventing the photosensitive medium from being undesirably moved in the direction perpendicular to the transportation direction. Also during this time period, the photosensitive medium is irradiated by a fade lamp to reduce electric charges on the photosensitive medium.

Electrophotographic apparatus having an intermediate transfer device and

An intermediate transcription drum is supported so as to be driven in contacting relationship with a photosensitive belt. The rotating speed of the photosensitive belt driving motor is controlled by a control unit such that one rotation cycle of the intermediate transcription drum becomes a given cycle. An adjustment of the speed control data for the photosensitive belt driving motor is performed in the interval between electrostatic latent image forming. Thereby, a speed difference between the photosensitive belt and the intermediate transcription drum does not occur, and a plurality of the toner images can be transferred and accurately superposed onto the outer surface of the intermediate transcription drum.

Color printer with transfer and superposition of different color toner

The present invention relates to a desk-top type color electro-photographic apparatus which is easy in use, small in size and light in weight, wherein maintenance such as changing its photosensitive member can be performed by a user and color adjustment is performed with high accuracy of less than 100 .mu.m. Developing units for four colors are placed in a rank, a single endless-belt-shaped photosensitive member being placed below them to form an approximately oval shape, the photosensitive member being touched with a transfer member on its major axis side to transfer each color of images. In addition to this, the photosensitive member is employed a cartridge type for easiness of user's maintenance and constructed such that highly accurate positioning between the body of apparatus and the cartridge can be performed. Effect of the eccentricity of pulleys is decreased by means of making the pulleys wrapped with the photosensitive member have the identical diameter and making the diameter of the transfer member integer times as large as that of the pulley.

Color electro-photographic apparatus with endless-belt-shaped

The present invention provides an electrophotographic copying apparatus in which a copy sheet is attracted to and delivered by a transfer belt to perform a transfer operation, wherein a sag of the leading end of the copy sheet is removed to prevent the copy sheet from being attracted to a photoreceptor, venting method of preventing attraction of the copy sheet. Stacked copy sheets are individually separately supplied, with each of the copy sheets being electrostatically attracted to and delivered by the transfer belt. The copy sheet is held between the photoreceptor and the transfer belt and is in contact with them. The photoreceptor carries an electrostatic latent image corresponding to an image information and a toner electrostatically attracted to the electrostatic latent image. The toner image on the photoreceptor is transferred to the copy sheet. The leading end of the copy sheet delivered to a transfer section defined by the photoreceptor, the transfer belt and a transfer corrotron is slightly bent toward the photoreceptor.

Electrophotograhic apparatus and method for preventing attraction of

A method for xerographic printing, comprises the steps of, holding a part of a work sheet at a position other than a leading end of the work sheet, before the leading end contacts with a toner image forming surface on which a toner image is formed by an electrostatic, charge of toner, holding both surfaces of the leading end of the work sheet and applying a frictional force to at least one of the surfaces of the leading end so that a tension is applied to the work sheet between the held part and the leading end, before the leading end contacts with the toner image forming surface, and making the work sheet contact with the toner image forming surface, and transferring the toner image from the toner image forming surface to the surface of the work sheet by generating an electric field for attracting the charged toner to the surface of the work sheet.

Method and apparatus for preventing attraction of a work sheet to a

A copy sheet, to which a developed image has been transferred by a transfer device, continues to be attracted to a copy sheet carrying surface of an insulating film and delivered toward a fusing roller pair. A force in a direction for pressing the copy sheet toward the insulating film is exerted, by an attraction strengthening device, on the copy sheet which is passing the vicinity of a downstream end of the copy sheet carrying surface after the transfer operation. This force strengthens a force for retaining the copy sheet on the copy sheet carrying surface of the insulating film, so as to hinder a portion of the copy sheet from being bent upwardly to the side of a photoreceptor and separated from the insulating film. Thus, separation of the copy sheet from the insulating film can be prevented from extending as far as a transfer position.

Electrophotographic copying apparatus

A cleaning device for an electrophotographic copying machine includes a blade mounted on a housing so as to scrape off a residual toner from the surface of a photosensitive member. A seal member is mounted on the housing so as to guide the scraped-off toner into the housing to collect the toner in the housing. A rotary screw discharges the collected toner from the housing. A vibrating member is mounted on the housing and disposed adjacent to and inwardly of the seal member. The vibrating member includes a plate-like portion having an edge portion contacted with the rotary screws, and is adapted to be vibrated during rotation of the rotary screw. The plate-like portion is formed with a number of slits spaced apart from each other by a distance smaller than a pitch of the rotary screw, so as to enable to effectively vibrate the plate-like portion of the vibrating member.

Growing community of inventors

Tsukuba, Japan

Masaru Nakano