Ricoh Company, Ltd.

Motonori Hanada

Tadashi Shinohara

Kouta Fujimori

Jun Hosokawa

Hajime Oyama

Nobuo Iwata

Yasushi Nakazato

Hideo Nakagawa

Kazuhiko Kobayashi

Takatsugu Fujishiro

Tetsuo Yamanaka

Toshiya Sato

Hiroyasu Shijo

Nobuhiko Umezawa

Kazuhiko Yuuki

Mitsugu Sugiyama

A method of color displacement detection for use in a color image forming apparatus sequentially forming image layers in different colors on a photosensitive member and overlaying the image layers on one after another into a color image on a transferring member. This method includes steps of forming, detecting, and calculating. The forming step forms a predetermined number of mark sets within one circumferential length surface of the transferring member. Each of the predetermined number of mark sets includes a predetermined number of different color marks arranged in a line in a moving direction of the transferring member. The detecting step detects the predetermined number of mark sets formed on the transfer member. The calculating step calculates mean values of displacement amounts of same color marks in different mark sets in the predetermined number of mark sets relative to respectively corresponding reference positions.

Method and apparatus for image forming capable of effectively performing color displacement detection

The present invention provides an electro photographic image forming apparatus comprising a replacement assembly having a toner container attachable to the image forming apparatus, a feeding unit to feed toner from the toner container to a development unit, and a read/write non-volatile memory, wherein, the image forming apparatus comprising an estimation unit which generates information in such way that first, the estimation unit obtains an amount of a toner feed period for the feeding unit during forming images, next, accumulates the amount of a toner feed period into an accumulated sum of the amount of a toner feed periods, then, generates the information on the amount of toner in the replacement assembly and stores the information in the read/write non-volatile memory.

Image forming apparatus, replacement assembly for image forming apparatus and integrated circuit chip therefor

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

A developing unit of the present invention includes a developing roller facing a photoconductive element and formed with a magnetic layer on its circumference. The magnetic layer has a plurality of magnetic poles of opposite polarities alternating with each other and each extending in the axial direction of the developing roller. A developer consisting of magnetic particles an toner are deposited on the developing roller by the magnetic poles and conveyed by the roller to the photoconductive element carrying a latent image thereon, thereby developing the latent image. An agitator for agitating the magnetic particles and toner is positioned relative to the developing roller such that a blade thereof has an agitation range overlapping with the magnetic force range of the magnet layer. With this configuration, it is possible to insure high quality images free from background contamination and toner scattering while extending the service life of the developing unit.

Developing unit for an image forming apparatus having a magnetic

Growing community of inventors

Kanagawa-ken, Japan

Motonori Hanada