Sharp Kabushiki Kaisha Corporation

Hidetoshi Atsumi

Atsushi Ogo

Junko Yabuta

Norio Tomita

Shuhji Fujii

Yasuaki Fukada

Tatsuya Inoue

Yoshiharu Yoneda

Shinji Nakazawa

Fuminori Miyoshi

Koji Wakamoto

Ryosuke Sakai

Fuminori Miyoshii

The image forming apparatus includes: a paper feed unit; a print unit; a registration roller; a sheet leading end sensor provided downstream, in a transport direction of the recording paper, of the registration roller; a time measuring unit for measuring a time from a start point of transportation of the recording paper by the registration roller to a point of detection of the leading end of the recording paper by the sheet leading end sensor; a memory unit for storing a reference image forming time and a reference time; a print control unit; and an arithmetic unit for obtaining a difference between the reference time and the time detected by the time measuring unit. The print control unit adjusts the length of the image forming period in accordance with the adjusted image forming time determined based on the difference obtained by the arithmetic unit and the reference image forming time.

Image forming apparatus capable of adjusting print position of image on recording paper

An image forming apparatus includes a high speed correction mode in which, at the time of a successive image forming process on a plurality of recording sheets, a preset number of recording sheets among the plurality of recording sheets are subjected to image formation based on a corrected image writing position, and other recording sheets are subjected to image formation based on the corrected image writing position; and a linear correction mode in which the plurality of recording sheets are subjected to image formation based on the corrected image writing position; and performs switching to either one of the high speed correction mode and the linear correction mode according to a correction amount &#x3b2;b for a recording sheet detected at the time of image formation with respect to a correction amount &#x3b2;a for the preset number of recording sheets.

Image forming apparatus capable of correcting trasport position displacement of recording sheet

A pair of registration rollers are provided upstream in a paper transport path from an image forming position, and a paper transport position detection portion is provided upstream in the paper transport path from the pair of registration rollers. When consecutive print processing on a plurality of sheets of paper is performed, a paper transport position in the paper transport path is detected by the paper transport position detection portion for a sheet of paper that has been set in advance among the plurality of sheets of paper. A correction amount of a position for image writing to a photosensitive drum is determined based on the paper transport position, and correction of the image writing position is performed based on the correction amount. Image forming on the sheet of paper is performed at the image forming position based on the image writing position after correction, and image forming on other sheets of paper after the sheet of paper that was set in advance is performed at the image forming position based on the image writing position after correction.

Image forming apparatus

The present invention provides a sheet feeding apparatus including an overlapped feeding detection apparatus which can securely detect overlapped feeding as to a sheet being fed, and a document feeding apparatus and an image processing apparatus including the sheet feeding apparatus. A paper feeding apparatusincludes a paper feed tray, a pickup roller, a paper roller, a sorting roller, feeding rollers, resist rollers, a paper ejection roller, a passage detection sensor, an overlapped feeding detection sensorand a second detection apparatus. Recording paper is delivered from the paper feed trayby the pickup rolleraccording to a printing instruction from a user. The recording paper is fed to the resist rollersthrough the paper roller, the sorting roller, the feeding rollersand the passage detection sensor. The recording paper temporarily stops at the resist rollers. In this case, the overlapped feeding detection sensordetects overlapped feeding of the recording paper.

Sheet feeding apparatus, and document feeding apparatus and image processing apparatus including the same

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Osaka, Japan

Hidetoshi Atsumi