Ricoh Company, Ltd.

Mitsugu Sugiyama

Tadashi Shinohara

Yutaka Shio

Nobuo Iwata

Tomonori Yabuta

Yasushi Nakazato

Toshiya Sato

Eiichi Sasaki

Kouichi Irie

Makoto Tanaka

Hideo Nakagawa

Hiroyuki Shibaki

Kiyoshi Ohshima

Rikio Kasahara

Motonori Hanada

Hisayo Kondo

Kohki Sakamoto

A color image forming apparatus generally includes a plurality of image forming units for each generating an image in a predetermined color. Since these images in various colors are placed on top of each other in an overlapping manner, the positional placement of these images is critical. To correct the misalignment in an efficient manner, a new technique is disclosed to perform the density determination in advance of the misalignment correction. The previously detected density level is stored prior to determine the positional misalignment among the color image forming units.

Method, system and software program for correcting positional color misalignment

An image forming apparatus includes a plurality of image formation units which print an image of different color on a paper and also form positional deviation detection marks and image density regulation marks, on a conveyer belt or on at least one of a recording medium and an intermediate transfer body that conveys the paper, when such a request is received. When requests for formation of the positional deviation detection marks and the request for the formation of the image density regulation marks is received at the same time or at substantially the same time, the main CPU orchestrates the conveyer belt and the image forming units to form the positional deviation detection marks and the image density regulation marks in continuation.

Color image forming apparatus

An image forming apparatus, particularly a color image forming apparatus, of the present invention distinguishes a register mark and the background of a conveying member on the basis of the level of a signal representative of the background and the peak value or the bottom value of the signal. The apparatus can therefore accurately detect deviation between images of different colors and correct it.

Image forming apparatus which corrects deviations between images of different colors

An apparatus and method of forming a color image on a recording sheet by transferring respective images onto a single recording sheet conveyed by a conveying belt, where the combination of the respective images form the color image. The respective color images are formed with a plurality of electrophotographic processing sections disposed along the conveying belt such that the respective color images are superimposed on one another to make the color image. The electrophotographic processing sections also form more than two colors, of a same pattern, of image positional deviation detecting marks. The image positional deviation detecting marks include a line in a main scanning direction and another line positioned at an incline with respect to the former line in order on the conveying belt. A detector is included that detects the image positional deviation detecting mark with a single detecting device composed of a light source, a slit, and a light accepting element.

Color image forming apparatus and method of obtaining color images with decreased image positional deviation

Color image forming apparatus and method of obtaining color images with

In a color image forming apparatus, a test pattern is formed by a color toner and provided with multiple tones by a dither method. The toner density of the test pattern is accurately read by a simple structure and faithfully corresponds to the actual toner density.

An apparatus for a rotational speed detecting includes a rotating disc having plural slits in a circumferential direction. A radiant element radiates light rays through the slits. A photodetector receives the rays radiated by the radiant element. Peak detectors detects peak points of the detected signal and a calculator calculates a rotational speed. The photodetector include two photodetectors separated by a distance .DELTA.L.

Apparatus for detecting rotational speed

A device for adjusting the position of a deflecting mirror included in an image forming apparatus, particularly one including a plurality of photoconductive elements, is disclosed. The device includes eccentric cams rotatable to adjust the position of the deflecting mirror.

Deflecting mirror adjusting device for an image forming apparatus

Apparatus for calibrating toner density for color images

In a device for storing printings, film sheets or similar recording media driven out or an image forming apparatus, bins are each inclined from a top sheet inlet thereof to a bottom sheet outlet thereof. When all the bins are full, such a condition is reported to users. Users having left sheets in the trays for a long period of time are alerted by a warning message. Sheets become needless for users can be automatically disposed of by commands from user stations. A user passes an I.D. card through a card reader to enter an I.D. number, opening a bin corresponding to the I.D. number, dropping the sheet onto a fence for user access.

Growing community of inventors

Yokohama, Japan

Mitsugu Sugiyama