Canon Kabushiki Kaisha

Kouichi Hashimoto

Yoshiyuki Komiya

Fumiteru Gomi

Atsushi Takeda

Kenichi Shibuya

Shuichi Kadota

Yuichiro Toyohara

Yoichi Kimura

Satoru Fukushima

Makoto Ohki

Shigeru Matsuzaki

Ken-ichiro Kitajima

An image forming apparatus includes an image bearing member; a charger for electrically charging the image bearing member; an electrostatic image forming device for forming an electrostatic image by selectively discharging a surface of the charged image bearing member; a developer for developing the electrostatic image formed on the image bearing member into a toner image; a transfer device for transferring the toner image from the image bearing member onto a transfer material; wherein the charger is capable of collecting residual toner from the image bearing member after an image transfer operation; an electric field forming device forms an electric field between the charger and the image bearing member to transfer the toner in the charger to the image bearing member; and a controller controls a length of time during which the electric field forming device forms the electric field, wherein the controller controls the length of time substantially in accordance with wear of a surface of the image bearing member.

Image forming apparatus with changeable toner returning electric field application period

An image forming apparatus includes a plurality of image bearing members and a plurality of image forming devices for forming toner images on the respective image bearing members, wherein the toner images formed on the respective image bearing members by the respective image forming devices are successively transferred to a transfer medium, and wherein a toner image for identifying the apparatus is formed on the image bearing member having the highest temperature among the plurality of image bearing members.

Image forming apparatus featuring a temperature-sensitive apparatus identifying feature

An image forming apparatus includes an image bearing member which is movable; an electrifying device which makes contact with the image bearing member and electrifies the image bearing member; a developing device for developing a latent image on the image bearing member by toner; and an abutting member which is provided on a downstream side in a moving direction of the image bearing member with respect to the electrifying device and the contacting portion of the image bearing member and abuts against the image bearing member. The image bearing member, electrified by the electrifying device, is exposed to have the latent image formed thereon, a toner image formed on the image bearing member by the developing device is transferred to a recording material, and the developing device recovers residual toner on the image bearing member after transfer.

Image forming apparatus having a member for barring an electrification particle form leaking

Toner particles fly off from a photosensitive drum to an exposure light emitting portion by a change of electric potential distribution on the photosensitive drum caused by image exposure in a following process. This causes a poor copy of an image by adhering the toner particles to the exposure light emitting portion. This phenomena affects a tandem type of copiers with multi-stations including photosensitive drums and exposure light emitting positions. An apparatus capable of suppressing toner adhesion to an exposure is provided to solve the above problem.

Image forming apparatus with conductive member adjoining light irradiating portion

An image forming apparatus includes an image bearing member and a charging device for electrically charging the image bearing member. The charging means includes a particle carrying member for receiving a charging bias voltage for carrying electrocondusctive magnetic particles. The particle carrying member is provided with an electrically insulated portion at an end portion within a region in which the magnetic particles are carried. An electrectrostatic image forming device forms an electrostatic image on the image bearing member charged by the charging device. A developing device develops the electrostatic image on the image bearing member. The developing device includes a developer carrying member for carrying a magnetic developer and a magnetic field generating device provided in the developer carrying member wherein the electrically insulating portion is outside a longitudinal end of the magnetic field generating device.

Image forming apparatus featuring a particle carrying charging member and a developing device including a magnetic field generating device

An image forming apparatus includes an image bearing member for bearing a toner image; a transfer device for transferring the toner image onto a transfer material from the image bearing member; a charger for electrically charging the image bearing member, the charger being contactable to residual toner remaining on the image bearing member after transfer of the toner image by the transfer device; a voltage applicator for applying DC and AC voltages to the charger; an image forming device for forming an electrostatic image on the image bearing member charged by the charger; a developing device for developing the electrostatic image by toner; an integrator for integrating degree of usage of the apparatus; and a controller for controlling the AC voltage applied to the charger in accordance with the integrated degree of usage provided by the integrator.

Image forming apparatus capable of properly controlling ac voltage applied to a charger

An image forming apparatus in which each of first and second image forming device is in contact with surfaces of first and second image bearing members from which no after-transfer residual toner is removed includes a rotating charging member contacting first and second image bearing members, and a developing unit for developing an electrostatic image on the image bearing member and rotation controlling device rotates the second image bearing member and the charging member of the second image forming device during image formation only with the first image forming device.

Image forming apparatus

An image forming apparatus has an auxiliary charging device provided near a transfer device side of the charging device for charging an image forming apparatus including an image bearing member bearing an electrostatic image thereon. The charging device charges the image bearing member. The charging device constitutes electrically conductive magnetic particles in contact with the image bearing member to thereby effect charging. The image forming device forms an electrostatic image on the image bearing device charged by the charging device. A developing device develops the electrostatic image on the image bearing member using a toner. A transfer device transfers the toner image on the image bearing member to a transfer material. An auxiliary charging device provided near the transfer means side of the charging device charges the residual toner after transfer to a polarity opposite to a charging polarity of the charging device, wherein the magnetic particles temporarily collect the residual toner. A shield device shields the charging device and the auxiliary charging device.

Image forming apparatus shielding charging device and auxiliary charging device

An image forming apparatus includes an image bearing member for bearing a toner image and a transfer device for transferring the toner image from the image bearing member onto a transfer material. A charging member contacts a surface of the image bearing member from which residual toner is not removed to electrically charge the image bearing member. The charging member is capable of temporarily collecting the residual toner. A cleaning device applies, to the charging member, a cleaning voltage for returning the toner to the image bearing member. An image forming device forms an electrostatic image on the image bearing member having been charged by the charging device. A developing device develops the electrostatic image on the image bearing member and collects the toner from the image bearing member. A controller controls the cleaning device to vary a cleaning condition of the charging member.

Image forming apparatus with a controlled cleaning operation feature

A charging apparatus includes a magnetic brush charging member for being supplied with a voltage to electrically charge a member to be charged, said charging member including a magnetic particle layer contactable to the member to be charged and a carrying member for carrying the magnetic particle layers, wherein said magnetic particle layer is moved along a peripheral surface of said carrying member; and stirring means, contactable to said magnetic particle layer carried by said carrying member, for stirring said magnetic particle layer in a longitudinal direction of said carrying member.

Charging device and image forming apparatus

The present invention relates to an image forming method in which charges are injected into an image bearing member having a charge injecting layer on a surface thereof to thereby charge it to a predetermined polarity and charges of an opposite polarity to the predetermined polarity are imparted to the image bearing member before image formation.

Image forming method for preventing an uneven potential of an image

A charging device includes a charging member for being supplied with a voltage to electrically charge a rotatable member to be charged, the charging member including a magnetic particle layer contactable to the member to be charged, and a carrying member for carrying the magnetic particle layer; wherein the member to be charged starts to rotate after start of application of the voltage and after the start of rotation of the carrying member.

Charging apparatus and image forming apparatus

An image forming apparatus includes an image bearing member; a charging member, contactable to said image bearing member, for being supplied with a voltage to charge said image bearing member; a developing device for forming a toner image by developing with toner an electrostatic image formed on said image bearing member, and also being capable of cleaning said image bearing member to remove residual toner; and a transferring device for transferring the toner image onto a transfer material. When the apparatus stops during an image forming operation as during a jam, the voltage applied to said charging member is a superimposed voltage of an AC voltage and DC voltage and is a DC voltage without the AC voltage thereafter between resumption after jamming and the start of image formation.

Image forming apparatus having charging member with control of voltage

An image forming apparatus includes an image bearing member for bearing an image. A charging device is supplied with a voltage. The charging device includes a magnetic brush contactable to the image bearing member to electrically charge the image bearing member. A developing device develops, at a developing position, an electrostatic image formed on the image bearing member using a charging operation of the charging device, with toner having the same polarity as a charging polarity of the charging device, into a toner image. The developing device is capable of removing residual toner from the image bearing member. The developing device stops its developing operation if an area of the image bearing member, which has been charged by the charging device when the charging device is being supplied with an oscillating voltage in the form of superimposed AC and DC voltages, is still at the developing position.

Image forming apparatus having a developing/cleaning device

An image forming apparatus includes an image bearing member and a charging unit having magnetic particles that are contactable with the image bearing member. An electrostatic image forming unit forms an electrostatic image on the charged image bearing member. A developing device develops an electrostatic image on the image bearing member with toner that includes toner and magnetic carrier. A detecting unit detects the toner content of the developer and a toner supply unit supplies the toner into the developing unit when the detected toner content is lower than a predetermined level. A calculating unit calculates the changing rate of the toner content from an output of the detecting unit and a warning unit warns that a changing rate of the toner content is larger than a predetermined level.

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Numazu, Japan

Kouichi Hashimoto