Sharp Kabushiki Kaisha Corporation

Fuji Electric Co., Ltd.

Teruhiko Noguchi

Jitsuo Masuda

Hiroshi Kinashi

Itaru Kawabata

Yoshiharu Tsujimoto

Ken Yamagishi

Katsushi Inoue

Yuhi Yui

Junji Morimoto

Yuji Okamoto

Hideaki Hagihara

Syouichi Fujita

Hiromu Sasaki

Takahiro Bito

Tadayuki Sawai

Kouichi Takenouchi

Kazuya Adachi

Yukihisa Imaue

Keizo Kitamura

Tatsuo Tanaka

Tooru Nakata

Kunio Otsuki

Tatsuya Itou

A photosensitive element is produced with a minimum amount of a conductive synthetic resin material. A draft for injection molding is formed in the inner circumferential surface as a supporting body, and a driven member provided with a gear is fixed to the end of the supporting body with a smaller inner diameter, that is, the thicker end. A driven portion in which a plurality of projections and depressions are formed alternately to be adjacent to each other in the circumferential direction is arranged on an axial end of a cylindrical supporting body made of a conductive synthetic resin, including a photosensitive layer on the outer circumferential surface. By a joint member removably engaged with the driven portion, the supporting body is rotated around the axis. In one arrangement, only the end of the supporting body is solid. In another arrangement, the supporting body is solid in the almost entire length in the axial direction.

Photosensitive element for electrophotography

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

Electrophotographic apparatus according to this invention are controlled in different ways such that quality of produced images is not affected by deterioration of the developing agent or the condition of the photoreceptor. A timer may be provided to detect the duration of a rest period to adjust the speed of development accordingly as well as by the number of copies produced. Similar control may be effected by measuring the surface voltage of the photoreceptor by a voltage detector and by adjusting the output level of the principal charger used for uniformly charging the photoreceptor prior to a development process.

Electrophotographic apparatus controlling image quality according to

An image formation apparatus having a cleaning process for removing defective toner from the developing unit during a non-image formation rotation of the photoreceptor drum. The image formation apparatus includes a reverse polarity charger for charging the photoreceptor drum to an opposite polarity from the polarity that is used for forming an electrostatic latent image. The reverse polarity charger allows defective toner to be removed from the surface of the photoreceptor during a warming-up process of the apparatus or after a predetermined number of image forming processes have been performed.

Device for removing defective developer agent from a developing unit of

Before a photoreceptor for an electrophotographic image forming apparatus is uniformly charged at the beginning of a process for forming a latent electrostatic image thereon, the photoreceptor is exposed to charge-removing light for stabilizing the surface potential such that a high-quality image can be obtained. The level of exposure is modified in view of the fatigue and recovery characteristics of the photoreceptor. During a continuous operation of the photoreceptor, the level is logarithmically reduced. When the photoreceptor is started again after a rest period, the initial level of exposure is adjusted by logarithmically increasing it according to the length of the rest period as well as in view of the level of exposure prior to the rest period.

Method of stabilizing surface potential of photoreceptor for

A discharging apparatus for use in a copying machine for discharging the photoreceptor layer laminated on a drum includes a short wavelength light source for producing a light having a wavelength shorter than 6000 angstrom, and a long wavelength light source for producing a light having a wavelength longer than 6200 angstrom. A control circuit is provided for controlling both light sources such that both light sources are turned on during at least one complete rotation of the drum before an exposure of a light image on the photoreceptor layer.

Discharging apparatus and method for use in a copying machine

A copying machine with a multiple transport function having a separation charger for separating from the photoreceptor surface copy paper with an image transferred thereon and a circulating transport passage formed from the paper discharge block to the paper feed block so that it is possible to select the single-sided copy mode for allowing the copy paper to be discharged outside the copying machine after the copying process, the duplex copy mode for allowing the copy paper undergoing one copying process to be led through the circulating transport passage to the copying process block as reversed, or the composite copy mode for allowing the copy paper undergoing one copying process to be led through the circulating transport passage to the copying process block without being reversed. The copying machine with a multiple transport function includes a current controller which sets current applied to the separation charger for the second copying process at a larger value in the composite copy mode and at a smaller value in the duplex copy mode than that for the copying process in the single-sided copy mode.

Growing community of inventors

Sakai, Japan

Teruhiko Noguchi