Sharp Kabushiki Kaisha Corporation

Kouji Wakamoto

Tatsuya Inoue

Toshiki Takiguchi

Junya Masuda

Toshihiko Seike

Takashi Yamanaka

Tatsuya Shinkawa

Kan Mukai

Takahisa Narikiyo

Syoichiro Yoshiura

Hiroshi Ishii

Yasuhiro Takai

Tsutomu Yoshimoto

Shiro Narikawa

Shinji Sugita

Masao Matsui

Kiyoshi Sasoh

The elastic force of a springin a direction of an arrow X is applied to an endA of a coil springA in a direction of an arrow Y through a holding plate. The endA of the coil springA is engaged with a holding holeand regulated from moving in the direction of the arrow Y. The elastic force of the springin the direction of the arrow X is constantly applied to the coil springA in a direction in which the peripheral surface of the support postis tightened.

Arm rotating device and image forming apparatus provided with the same

A unit drawing mechanism according to the present invention includes a drawing unit, a lever, a fixture, a preventer, a linkage, and a lever holder. The drawing unit can move along a movement path between a retracted position in an apparatus and an exposed position outside the apparatus. The lever is supported pivotably on the front side of the drawing unit. The fixture locks the drawing unit in the retracted position. The preventer prevents the drawing unit from moving from the exposed position. The linkage links the lever to the fixture and the preventer. The lever holder holds the lever in a first angular position, a second angular position, and a third angular position when the drawing unit is locked by the fixture, positioned on the movement path, and prevented by the preventer from moving from the exposed position, respectively.

Unit drawing mechanism and image recorder

In an image forming apparatus of the present invention, an idle roller once stops rotating when a front edge of a sheet conveyed reaches the idle roller. The idle roller restarts rotating at such a timing that a front edge of a toner image on a photoreceptor and a front edge of an image writing position on the sheet are aligned with each other. Then, even if a rear edge of the sheet is still in the idle roller, the idle roller stops rotating when the front edge of the sheet is sandwiched between a transfer roller and the photoreceptor. By carrying out such operations, it is possible to avoid by a very simple way an occurrence of a slip phenomenon that is a phenomenon of slipping of the sheet with respect to the photoreceptor while suppressing a reduction in image quality as much as possible. In addition, it is also possible to surely secure a blank space formed at a rear edge portion of the sheet.

Image forming apparatus

An image forming apparatus carries out an image processing with respect to a sheet size and image information based on a print request to obtain a write image on a photoreceptor. On the basis of a printing ratio of the write image, the apparatus predicts occurrence of an image elongation. If the apparatus predicts that the image elongation occurs, the apparatus calculates a bending amount of a bended portion based on the difference between peripheral velocities of a photoreceptor and the idle roller, and the apparatus variably controls the peripheral velocity of an idle roller so that the bending amount is adjusted so as not to cause a slip phenomenon. It is possible to avoid the occurrence of a phenomenon of slipping of a sheet with respect to the photoreceptor without lowering image quality, and to surely secure a blank space formed at a rear edge portion of the sheet.

A fixing unit includes a heat roller and a pressing roller that comes in pressure contact with the heat roller, and passes the recording paper with an unfixed toner image formed thereon through the nip between the heat roller and pressing roller to thereby fix the toner image to the recording paper by applying heat and pressure thereto. A cleaning device for removing the toner remaining on the heat roller or pressing roller in the fixing unit includes cleaning rollers made of metal arranged in press-contact with the heat roller and pressing roller, the peripheral surface of the cleaning rollers being formed with projected and indented shapes to thereby remove the leftover toner appropriately.

Cleaning device for a fixing unit

An image forming apparatus of the present invention carries out an image processing with respect to image information which is to be printed. The image forming apparatus predicts the occurrence of an image elongation which may occur due to slippage of a recording material with respect to the electrostatic image drum, and specifies an image elongation occurring area on the basis of a printing ratio of the image information. If the occurrence of slippage, and thus image elongation is predicted, the amount of the image elongation occurring area to be shortened is calculated. The image information is then modified to obtain write image information that is shortened based on the calculated shortening amount. This write image information is then used to form the electrostatic latent image that is developed and transferred to a recording material. Thus, even slippage does occur, it is possible to accurately form the desired image on the recording material.

The present invention provides a fixing device for fixing a toner image formed on paper by sandwiching the paper in a nip region between a heating roller and a pressing roller and pressing the paper while heating the paper to a fixing temperature. This fixing device includes a cleaning roller that is in contact with the pressing roller, and temperature control means that sets a temperature of the heating roller to a cleaning temperature that is higher than the fixing temperature.

Fixing device

An image forming apparatus of the present invention predicts the occurrence of an image elongation, in other words, predicts that an image transferred is lengthened on a sheet due to slipping of the sheet with respect to a photoreceptor at a transfer nip portion. If the occurrence of the image elongation is predicted, the amount of a rear edge portion to be deleted from an electrostatic latent image is obtained on the basis of a sheet rear edge void setting change table, the amount of the rear edge portion to be deleted is added to the default amount of a rear edge void, a portion corresponding to the rear edge portion of an image of image information is deleted, and a printing process is carried out. In this way, even if a slip phenomenon occurs, in other words, the sheet slips with respect to the photoreceptor, it is possible to surely secure a blank space at a rear edge portion of the sheet.

An image forming apparatus includes, for example, a first knob serving as a first operating member for manually turning a registration roller member in a sheet transporting unit and a second knob serving as a second operating member for manually turning a fixing roller in a fixing device. The first and second operating devices, such as knobs, are provided in such a manner as to be exposed onto a side of the apparatus body facing a direction perpendicular to a direction in which the cabinet may be opened.

Growing community of inventors

Nara, Japan

Kouji Wakamoto