Canon Kabushiki Kaisha

Fuji Xerox Co., Ltd.

Akio Noguchi

Makoto Takeuchi

Seiji Uchiyama

Yukihide Ushio

Yoji Serizawa

Kazuro Yamada

Shimpei Matsuo

Junichi Kato

Masahiro Goto

Koichi Hiroshima

Shinichi Tsukida

Takahiro Inoue

Koichi Suwa

Masaki Ojima

Manabu Takano

Haruhiko Moriguchi

Toshiharu Inui

Hiromichi Yamada

Hiroshi Hashimoto

Masayuki Hisatake

Yukio Inagi, Isaka

Kazurou Yamada

Youji Serizawa

Shinpei Matsuo

Takashi Ohmori

Katsuhisa Ogawa

Shunichi Masuda

Hideyuki Yano

Takashi Nakahara

Kenjiro Hori

Hiroyuki Nakamura

Satoshi Akiyama

Eihiro Sakaki

Toshio Yoshimoto

Hiroshi Atobe

Hakaru Muto

Yoshimi Kuramochi

Norihiko Koizumi

Hiromiichi Yamada

In a laser beam printer, automatic optical quantity (APC) control is performed based on an optical quantity detection output to generate a laser beam having a predetermined quantity of light. In each scanning cycle, APC is effected by utilizing a period (unblanking period) in which the laser device is forcibly actuated to generate a horizontal synchronization signal. The unblanking period may be changed according to the print paper size or image formation/non-image-formation periods. Also, light quantity control may be effected through a plurality of scanning cycles before image formation and may be effected by utilizing the unblanking period during the period corresponding to the intervals of print sheets. Techniques also provided to prevent a transfer unit from being contaminated by toner images formed as a byproduct of APC.

Image recording apparatus using optical beam for applying a transfer

An apparatus has a plurality of semiconductor cells as current switchings for driving a laser diode which exposes to light a photosensitive member so as to effect image recording. The semiconductor cells have each different characteristics, or same characteristics respectively. In response to the light amount signal corresponding to light quantity of the laser diode, a selector selects one or more of the semiconductor cells so as to supply a suitable driving current turned on or off later with an image signal. As a result, no fluctuations in the pulse duty ratio and the rise time are present in the entire driving current active range, thus improving the quality of a recorded image. The effect of selection by the selector is held for a certain recording time, whereby malfunction due to noises or the like can be avoided, and stable actions of the laser diode are ensured.

Device for driving a laser diode and an electrophotography type image

An image forming apparatus has a fixing device for fixing an image formed on a recording medium, a device for detecting an operating environment of the image forming apparatus, a selecting device for selecting a fixing device temperature in accordance with a detection result, and a control device for controlling the temperature of the fixing device to a selected fixing device temperature. The image forming apparatus is capable of efficiently bringing out the functions of a print engine thereof at a minimum cost without the need for adding a new high-speed device, achieving a higher printing speed and ensuring a good fixing property regardless of the thickness of paper used, while preventing wasteful energy consumption and adverse influences by heat.

Image forming apparatus with fixing temperature control

An image forming apparatus which converts character or pattern information into bit map information (pixel information) and forms an image based thereon. The image forming apparatus includes a light-beam generator for generating a modulated light beam, a light-beam deflector for scanning an image carrier, a device for feeding a sheet to registration rollers and a driver for driving the image carrier. A time period is provided to operate the light-beam deflector and the feeding device before the driver starts to drive the image carrier to form an image.

Image forming apparatus with image carrier and sheet feed drive control

An image forming apparatus comprises image information which outputs a sync signal and means generated image information synchronously with the sync signal; image forming means form an image on the basis of the image information at either one of a plurality of resolutions and which generates a sync request signal to request a transmission of the sync signal; and a resolution changeover means. When the image forming unit received the resolution change over request signal before the sync request signal is generated, the image forming unit executes the switching operation of the resolution, and if the image forming unit received the resolution changeover request signal after the sync request signal had been generated, the image forming unit does not execute the switching operation of the resolution.

Image forming apparatus having improved resolution switching capabilities

An image forming apparatus for adjusting image density includes an input device for inputting a plurality of image type information and a discriminating device for discriminating the image type information in accordance with a signal other than a signal to be recorded. An image forming circuit, such as a printer, forms an image on the basis of image type information. A density adjusting circuit adjusts the image forming density of the image forming circuit in accordance with the input image type information. The discriminating device inputs a signal indicative of whether the input image type information indicates a text image or a graphics image, or whether it denotes Japanese or a European language (e.g., English). The discriminating device also inputs a signal indicative of the kind of font included in the input image type information or a signal indicative of a resolution for an output image to be formed by the printer.

Image forming apparatus having density correction for image formation

An image forming apparatus includes a feeder means and a recorder. The feeder feeds a sheet of recording paper to a predetermined position in response to a spare paper feed signal instructing the feeding of the sheet of recording paper to the predetermined position preliminarily, and then feeds the sheet of recording paper being stopped at the predetermined position again in response to a record request signal. The recorder records an image on the sheet of recording paper fed by the feeder means through an electrophotographic process. The recorder means starts preparation to execute the electrophotographic process upon receiving the spare paper feed signal. As a result throughput is increased without causing other problems.

Image forming apparatus with fixer temperature control

An image forming apparatus which can adjust a density comprises: a first input device to input image information; a second input device to input the kind of image information; an image forming circuit such as a printer form an image on the basis of image information which can vary an image forming density; and a density adjusting circuit to adjust the image forming density of the image forming circuit in accordance with the kind of input image information. The second input device inputs a signal indicative of whether the input image information indicates a text image or a graphics image or whether it denotes Japanese or European/English language. The second input device inputs a signal indicative of the kind of font included in the input image information or a signal indicative of a resolution of an output image which is formed by the printer.

Image forming apparatus with optical reflective density of image

An image forming apparatus comprises image information which outputs a sync signal and generated image information synchronously with the sync signal; an image forming apparatus forms an image on the basis of the image information at either one of a plurality of resolutions and which generates a sync request signal to request a transmission of the sync signal; and a resolution changeover means. When the image forming unit received the resolution change over request signal before the sync request signal is generated, the image forming unit executes the switching operation of the resolution, and if the image forming unit received the resolution changeover request signal after the sync request signal had been generated, the image forming unit does not execute the switching operation of the resolution.

Image forming apparatus having plural printing resolutions

Image recording apparatus using optical beam

An image forming apparatus comprises a data receiver for receiving encoded character or graphic information in the unit of a page from the outside; a pixel converter for converting the encoded character or graphic information into pixel information; an image forming device for forming an image on a recording medium based on the pixel information; and a feeder for feeding the recording medium to said image forming device. In the apparatus, the feeder is adapted to feed the recording medium to a predetermined position prior to the completion of pixel conversion of a page by the pixel converter.

Image forming apparatus with feeder control based on pixel conversion

An image forming apparatus comprises includes a feeder means and recorder. The feeder feeds a sheet of recording paper to a predetermined position in response to a spare paper feed signal instructing the feeding of the sheet of recording paper to the predetermined position preliminarily, and then feeds the sheet of recording paper being stopped at the predetermined position again in response to a record request signal. The recorder records an image on the sheet of recording paper fed by the feeder means through an electrophotographic process. The recorder means starts preparation to execute the electrophotographic process upon receiving the spare paper feed signal. As a result, throughput is increased without causing other problems.

A driver IC for driving a light source comprises means for generating a constant current, switching means for switching the constant current supplied to the light source, first input terminal for inputting a first signal to modulate a light emitted by the light source, said switching means performing a switching operation in accordance with the first signal, and second input terminal for inputting a second signal so as to supply the constant current to the light source, irrespective of the first signal.

Image forming apparatus and constant current circuit switching device

A communication system includes a main control unit controlling a plurality of units, a transmitter for transmitting information between the main control unit and the plurality of units, and an error detector. The error detector can include a modulator and demodulator for modulating or demodulating the transmitted information on the basis of a predetermined rule. The error detector detects a communication error in the transmitted information in accordance with the predetermined rule. Alternatively, the error detector can include a transmitted data creator/analyzer for creating data based on the transmitted information in a state in which the information contains positive data and negative data of the same bit in one frame and analyzes data when the data is received. This error detector detects a communication error in the transmitted information on the basis of the comparison between the positive and negative data. The error detector can also include a space bit addition separator for creating data based on the transmitted information in a state in which a predetermined space bit is added in one frame and separates the space bit when the data is received. This error detector detects a communication error in the transmitted information on the basis of the timing at which the space bit and other bits appear.

Communication system for detecting a communication error in information

An image forming apparatus includes a feeder means and a recorder. The feeder feeds a sheet of recording paper to a predetermined position in response to a spare paper feed signal instructing the feeding as the sheet of recording paper to the predetermined position preliminarily, and then feeds the sheet of recording paper being stopped at the predetermined position again in response to a record request signal. The recorder records an image on the sheet of recording paper fed by the feeder means through an electrophotographic process. The recorder means starts preparation to execute the electrophotographic process upon receiving the spare paper feed signal. As a results, throughput is increased without causing other problems.

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Ebina, Japan

Akio Noguchi