Sharp Kabushiki Kaisha Corporation

Fuji Electric Co., Ltd.

Katsushi Inoue

Jitsuo Masuda

Teruhiko Noguchi

Toshiaki Ino

Toshihisa Ishida

Hiroshi Kinashi

Masato Asanuma

Itaru Kawabata

Mitsuhiro Hasegawa

Hideji Saiko

Kazuya Adachi

Yasuo Kitabatake

Kanshiro Okamoto

Keizo Kitamura

Tatsuo Tanaka

Kunio Otsuki

Katuaki Sumida

Tomoko Mamemoto

An image forming apparatus includes (i) a photosensitive drum for holding an electrostatic latent image on its surface, the photosensitive drum being driven to rotate by a motor, (ii) charging means for charging the surface of the photosensitive drum so that the surface has a predetermined polarity and a predetermined potential, (iii) exposing means for forming an electrostatic latent image by exposing the charged surface of the photosensitive drum, and (iv) developing means for developing the electrostatic latent image, and is arranged so that after stop of the motor due to occurrence of a trouble, during an inertial rotation time in which the photosensitive drum rotates due to an inertial force, the exposing means executes discharge exposure with respect to a charge remaining region on the surface of the photosensitive drum.

Image forming apparatus with discharging exposure after shutdown

An image forming apparatus has a developer container, a development device for developing a latent image formed on a surface of a photoreceptor drum by supplying toner to the latent image, and an agitation roller for supplying toner to the development device and agitating the toner in the developer container. The development device and the agitation roller are installed in the developer container. Moreover, the image forming apparatus includes a flying toner detecting device for detecting an amount of toner flying from the development device, and a control unit for controlling various developer operations such as the toner related agitating operation of the agitation roller, toner supply amount, etc. in response to a result of a detection performed by the flying toner detecting device. This structure prevents the toner from flying from the development device.

Image forming apparatus with flying toner detecting device

An image-quality stabilizer in a copying machine feedback-controls a charger output according to an amount of toner on a photoreceptor drum detected by a patch sensor during a rotation of the photoreceptor drum after a copying operation. The image-quality stabilizer counts time that the copying machine is unused, i.e., time that the photoreceptor drum is stopped being rotated using a timer, and one-way controls the charger output according to the time immediately before the next copying operation. With these controlling operations, it is possible to correct a change in the copy density which is caused when the copying machine is used or left unused without increasing the consumption of toner and impairing the responsiveness of the copying machine, thereby achieving stable image quality.

Image-quality stabilizer for use in an electrophotographic apparatus

A photoreceptor having a marking area whose optical reflection property differs from that of a non-marking area is formed in a portion of a surface of an electrically conductive substrate. The average line of a vertical section of the non-marking area cut across the border line with the marking area is M.sub.0 and the average line of a vertical section of the marking area cut across the border line is N.sub.0 and that straight lines touching the average lines M.sub.0 and N.sub.0 at the intersection of M.sub.0 and N.sub.0 are tangent lines M.sub.1 and N.sub.1, respectively, the acute angle .theta. between M.sub.1 and N.sub.1 is within the range of 0.degree..ltoreq..theta..ltoreq.30.degree.. Setting the angle .theta. within this range enables a photoconductive layer of a uniform characteristic to be laminated on the electrically conductive substrate even when the marking area is formed on the surface of the substrate. With this arrangement, since information for optimizing the image quality of copies is obtained from the same location of a photoreceptor drum with reference to the marking area, a photoreceptor for electrophotography always produces copies of stable image quality.

Photoreceptor for electrophotography

An image-quality stabilizer for an electrophotographic apparatus forms a toner patch on a photoreceptor drum, detects the amount of toner attracted to the photoreceptor drum by an optical sensor, and controls each processing device so that the detected value is equal to a reference value which has been detected and stored when the number of image forming operations performed is low. After the control, the toner patch is transferred to a transfer sheet, and the amount of toner remaining on the photoreceptor drum is detected. The reference value is adjusted based on the detected value so as to compensate for a lowering of transfer efficiency. Or the lowering of transfer efficiency is compensated by controlling variables such as transfer output so that the detected value is equal to a reference residual value which has been detected and stored when the number of image forming operations performed is low. This arrangement restrains a lowering of image density due to a change in the transfer efficiency. It is therefore possible to control stabilizing the image quality accurately and to form images of stable quality.

Image-quality stabilizer for an electrophotographic apparatus

Growing community of inventors

Yamatokoriyama, Japan

Katsushi Inoue