Canon Kabushiki Kaisha

Nobutoshi Yoshida

Takashi Saito

Tadashi Suzuki

Hideki Adachi

Masahiro Tomosada

Naoyuki Ohki

Hiroaki Takeda

Atsushi Takagi

Katsunobu Ohara

Nobuyuki Miyake

Yujiro Ando

Tsukasa Kuge

Takashi Hino

Tatsuya Tada

Hisaaki Senba

Keishi Ohsawa

Kazuki Tanaka

Atushi Takagi

Masahiro Katayama

Ikumi Omura

Nobuyuki Miyke

There is a multi-color copying apparatus having image processing functions which can easily designate arbitrary areas when the trimming or masking is executed. This apparatus comprises: an area designating device to designate the first area of the original; a first developing device to develop the image of the first area in the first color; a second developing device to develop the image of the second area in the second color; and a control circuit for making the first developing device operative without making the second developing device operative in accordance with the designation of the first area and, after completion of the development of the image of the first area, making the second developing device operative without making the first developing device operative. The control circuit inhibits the operation of the first or second developing device by moving the first or second developing device to a position away from the photo sensitive drum, or by applying the bias voltage to the first or second developing device such that the toner from the inoperative developing device is not deposited onto the drum.

Copying apparatus

A multiple image forming system for synthesizing images having different kinds of gradation characteristics of an original comprises: a latent image forming circuit for projecting a reflected light from the original onto a photo sensitive drum and forming an electrostatic latent image onto this drum; a developing unit to develop the latent image; and a control circuit to make the latent image forming circuit and the developing unit operative every gradation characteristic for the different gradation characteristic areas in the original, wherein the control circuit changes the latent image forming conditions such as an amount of exposing light to the original of the latent image forming circuit and the developing conditions such as a developing bias of the developing unit in accordance with the kind of gradation characteristic. With this system, the image areas having different kinds of gradation characteristics which mixedly exist in one original are automatically detected and the latent image forming circuit is automatically properly controlled, so that the proper image is reproduced.

Multiple image forming system

An image forming apparatus using two component developer. When a toner content in the developer becomes out of a predetermined range as a result of the consumption of the toner, a control device effects a toner replenishing operation, and simultaneously, the image forming operation is substantially delayed.

Image forming apparatus with delay during toner replenishment

A cleaning device which ensures perfect cleaning of the surface of an image bearing member by a cleaning device for cleaning toner remaining on the surface of the image bearing member and a cleaning roller disposed upstream of the cleaning device with respect to the direction of movement of the image bearing member and rotatable while being in contact with the surface of the image bearing member, the cleaning roller having an elastic outer layer of high hardness and an elastic inner layer of lower hardness than the outer layer.

Cleaning device

A fixing device for use in an image formation apparatus such as an electrophotographic copying apparatus or recording apparatus, and more particularly a fixing device in which a sheet such as paper having a toner image on the surface thereof is passed between a pair of rotatable members pressed against each other to thereby fix the toner image on the sheet. In the substance forming the surface of at least one of the pair of rotatable members, particles having a hardness higher than that of said substance are dispersed to enhance the fixativeness.

Pressure fixing device

Disclosed is a method for protecting a primary electrostatic latent image formed on a screen type photosensitive member. In the step for modulating ion streams or toner particle streams by the primary electrostatic latent image, due to a bias voltage impressed on the screen type photosensitive member natural corona discharge is generated by a corona discharge electrode used for forming a primary electrostatic latent image or natural discharge is generated between the photosensitive member and a conductor located close thereto so that the degradation or destruction of the primary electrostatic latent image result. The present invention provides the methods for solving this problem by electrically isolating the photosensitive member, the corona discharge electrodes and other conductors in the vicinity of the photoconductive member when a bias voltage is impressed on the latter.

Electrophotography

The present invention aims at improvement in the image forming method, wherein ion current is modulated in an image form, on the basis of which a secondary electrostatic latent image is formed on a recording sheet, an insulated drum, and other recording media, and the thus formed electrostatic latent image is developed. In more detail, the entire region of such sheet and drum where such secondary electrostatic latent image is formed is uniformly charged beforehand to a desired potential, whereby the fogging phenomenon to occur at the time of development, and changes in the formed image which take place due to variations in the modulating quantity of the ion current on account of deterioration in an ion current modulating element can be prevented. Setting of the member to form thereon such secondary electrostatic latent image at a desired arbitrary potential can be done by, for example, varying the voltage to be applied to a grid provided in a corona discharger.

Ion modulation imaging involves prior uniform charging of secondary

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Yokohama, Japan

Nobutoshi Yoshida