Sharp Kabushiki Kaisha Corporation

Kao Corporation

Itaru Kawabata

Hiroshi Kinashi

Teruhiko Noguchi

Jitsuo Masuda

Yuhi Yui

Syouichi Fujita

Yoshiharu Tsujimoto

Masato Asanuma

Hirofumi Sakita

Syoichiro Yoshiura

Masaru Tsuji

Eiichi Kido

Hiroaki Yoshida

Hideji Saiko

Kouichi Takenouchi

Keizo Fukunaga

Toyokazu Mori

Shinji Imagawa

Ken Yamagishi

Junji Morimoto

Yoshikazu Kawasaki

Yuji Okamoto

Yasuyuki Ishiguro

Hisashi Kunihiro

Mitsuru Tokuyama

Hideaki Hagihara

Hiroshi Kawahito

Shunju Anzai

Toshio Nishino

Hiromu Sasaki

Yoshiaki Sanada

Hideyuki Nishimura

Yoshiki Ichikawa

Hiroshi Kawamoto

Masayoshi Nawa

Yuichi Kazaki

Kouji Shinkawa

Eiji Sato

Yukihisa Imaue

Katsushi Inoue

Hidenobu Yamane

Masahiro Tsuji

Takao Hiroyasu

Shinya Gotoh

Tooru Nakata

Syunju Anzai

Fumito Mizoguti

Shintarou Hatano

To solve problems that the amount of reuse toner increases with time recovery of reuse toner is efficiently achieved while forming an image of high quality. In a toner replenishing apparatus, toner recovered by a cleaning unit is conveyed via conveying device and contained in a recovery toner container. When an amount of the recovery toner exceeds a predetermined capacity of the recovery toner container, the recovery toner flows into a fresh toner container over an upper edge of a partition wall. Fresh toner and recovery toner are replenished to a developing unit via a fresh toner replenishing roller and a recovery toner replenishing roller, respectively, and the ratio between fresh toner and recovery toner is selected so that the fresh toner occupies a larger part than the recovery toner. This ratio is controlled on the basis of the cumulative rotation time of a photoconductor drum counted by a counting device.

Toner replenishing apparatus and image forming apparatus equipped with same

A developing unit and an image forming apparatus includes drive and control mechanisms for the conveyance of collected toner and fresh toner in an uncomplicated structure and an uncomplicated toner supplying roller structure for the reduction in manufacturing cost. Fresh toner and collected toner stored in housing parts of a toner housing are discharged from an outlet via openings formed in a partitioning member for forwarding to a developing section by a toner supplying roller disposed to confront the outlet. The toner supplying roller is provided in common to fresh toner and collected toner. The toner supplying roller includes a single rotary shaft and a plurality of composite members which are fit into the rotary shaft. Each of the composite members has a cylindrical hollow body and a cylindrical elastic body which is fit onto the outer peripheral surface of the hollow body. The composite members are disposed correspondingly to the housing parts.

Developing unit and image forming apparatus

In an image forming apparatus having a developing unit for developing an image using toner, a toner box for withholding the toner, and a toner transportation section for transporting the toner withheld in the toner box to the developing unit, the toner transportation section includes a transportation screw portion having formed a spiral blade section on its shaft, a pipe section for controlling a toner transportation route by covering the transportation screw portion of the toner transportation section, and a toner flow suppressing section for suppressing flow of the toner from a space between the transportation screw and pipe section. Consequently, a toner transportation opening formed near the transportation section can be closed, and therefore, the flowing of toner into the developing unit can be controlled or reduced by a simple and inexpensive arrangement.

Image forming apparatus having developer supply device

The present invention is intended to provide a compact development apparatus using a nonmagnetic one-component toner. The apparatus comprises a toner storage container, a toner supply roller, a toner passage through which supplied toner passes, and an attracting fan for attracting the toner and generating a toner powder stream. The toner is held in the toner storage container. The toner supply roller supplies the toner from a supply port of the storage container. The toner passage is provided with an opening opposite to a photosensitive drum. The toner supplied into the toner passage and frictionally charged is attracted by the attracting fan. The toner travels from the opening to the drum. The toner adheres to an electrostatic latent image on the drum and thus the image is developed. Unused toner is transported into the toner passage and recovered.

Development apparatus for developing electrostatic latent image held by

A developing device incorporating a developer supply unit and a developer discharge section, in which a supply developer including a mixture of toner and carrier is successively supplied to a developer container from the developer supply unit and a deteriorated developer in the developer container is discharged through the developer discharge section. The developer supply unit has a sponge roller for selectively attracting toner to a surface thereof, a magnet roller for selectively attracting carrier to a surface thereof, and a member for scraping and bringing the toner and carrier attracted to these rollers into the developer container. The developer including toner and carrier in a predetermined ratio is thus stably supplied to the developer container. In another example of the developer supply unit, agitating of the developer is performed while shovelling the developer deposited in a lower part of the unit by a transport screw. With this structure, since the toner and carrier are evenly mixed in the unit, the developer having a uniform toner concentration is supplied to the developer container, thereby continuing satisfactory development.

Developing device with developer-supplying mechanism

A charger performs corona discharge by applying a voltage to a discharging electrode. The charger includes an electrode plate formed in the shape of a panel on the discharging electrode, a plurality of projecting portions disposed in an end portion of the electrode plate, and a plurality of projection groups formed in each of the projecting portions such that the projection groups are adjacent to each other in a thickness direction of the electrode plate.

Charger for performing a corona discharge

A charger charges a recording medium before irradiation of light to form an electrostatic latent image by irradiating light as an optical image onto a surface of the recording medium. The charger includes a discharging electrode having a plurality of projections for generating corona discharge to charge the recording medium surface, a conductive shield case having an opening face opposite to the recording medium and opposed to the discharging electrode, a holding member for holding the discharging electrode in the shield case in a state in which the discharging electrode is electrically insulated from the shield case, a conductive grid electrode electrically insulated and held between the discharging electrode and the recording medium, and a power supplying device for supplying a high voltage for discharge to the discharging electrode and setting a ratio of electric currents flowing through the grid electrode and the shield case such that these electric currents are approximately equal to each other. One form of the charger controllably moves the discharger electrode toward the recording medium for setting the value of the electric currents flowing through the grid electrode and the shield case until they are both equal to a predetermined reference value.

Corona charger for image forming apparatus providing uniform surface

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

A long life cleaning blade for image forming apparatus is formed of a rubber elastomer which contains, or has adhered on the surface thereof, an antistatic agent in an amount effective to prevent electrification.

Cleaning blade with a surface active antistatic agent

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.

Copying machine with multiple transport function

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Kashiba, Japan

Itaru Kawabata