Ricoh Company, Ltd.

Toshio Ohide

Kenichi Ono

Nobuyoshi Kaima

Hidetoshi Yamashita

Tatsuo Ohyama

Yumiko Kishi

An optical writing device includes two or more light sources. The two or more light sources can be driven independently, are placed away from each other in a sub-scanning direction of a photoreceptor, and each distance of beams emitted from the light sources to the photoreceptor is different. A phase control unit causes a difference in phase among timing control data of two or more beams emitted from the two or more light sources by a phase change amount, which is determined on the basis of beam position of the each beam on the photoreceptor in a main scanning direction and varies depending on the beam position. The modulating unit modulates the timing control data of the respective phase-controlled beams by a same clock.

Optical writing device, image forming apparatus, and optical writing method

An image forming apparatus includes a VCSEL that includes a plurality of light sources emitting light beams, an image processing unit, and write control units that send a sub-scanning start reference signal indicating a reference for starting image formation in a sub-scanning direction and start a control of driving the light sources for each of a plurality of colors when receiving image data from the image processing unit. The write control units perform a control of outputting the sub-scanning start reference signal at timing of any of a plurality of areas divided by the number of lines scanned simultaneously in a scan cycle in a main-scanning direction.

Image forming apparatus and image forming method

A novel image processing system includes a pixel position indicator and a pixel inserting unit. The pixel position indicator is configured to indicate insertion positions in the image data. The pixel inserting unit is configured to enlarge a size of the image data by inserting an additional pixel at each of the insertion positions and accordingly shifting the original pixels in a given direction. The additional pixel has a value lower than a given threshold. Each insertion position is at an approximate center of an area formed of pixels having values higher than the given threshold. A novel image forming apparatus incorporates such an image processing system and an electrophotographic system. The electrophotographic system is configured to form an image by irradiating a photoconductive surface with a laser beam according to the processed image data.

Image processing system and image forming apparatus incorporating same

A light-amount control apparatus for controlling an output light amount of light sources used for optical writing is disclosed. The apparatus includes one or more drive units for supplying a drive current to the light source; one or more drive-current setting units for determining an amount of the drive current provided to the light source from the drive unit; a light-amount detecting unit for detecting an output light from the light source; and outputting a voltage according to the detected light amount; and a processing unit for setting the drive current amount based on the detected value detected with the light-amount detecting unit.

Light amount control, optical writing, and image forming apparatuses having a plurality of drive-current setting units

An image forming apparatus using a multi-scan system is capable of forming an image at a high speed. An exposure device scans a surface of the photo conductor by light beams emitted by a plurality of light-emitting elements so as to simultaneously form a plurality of electrostatic latent images at a plurality of positions on the photo conductor, a pitch of the light beams in a sub scanning direction being smaller than a beam diameter defined by a value of an intensity of the light beam at which an intensity level of each light beam is 1/eof an intensity level at a center thereof, the electrostatic latent image being formed also at a position where the plurality of light beams overlaps with each other. A code of a plurality of levels is produced from image data in accordance with a pattern detection matrix. A pulse with output from the pattern detection processing means is produced with reference to pulse width data which designates a pulse width of each light beam previously set in response to the code.

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Kanagawa, Japan

Toshio Ohide