Ricoh Company, Ltd.

Hideo Yu

Mitsuru Takahashi

Takeshi Shintani

Shin Kayahara

Yasunori Kawaishi

Toshiaki Motohashi

Hideki Kamiyama

Takashi Bisaiji

Satoshi Takano

Jun Okamoto

Setsuo Soga

Itaru Matsuda

Yuko Harasawa

Yasuhiro Kohira

Katsuya Kawagoe

An image forming apparatus includes an image carrying member, an intermediate transfer member, a charging member, a transfer mechanism, a discharging member, a direct current voltage source, and a direct current voltage controller. The intermediate transfer member is deposited at a position facing and in contact with the image carrying member rotatably carrying a toner image on a rotating surface, and receives the toner image therefrom during a first transfer operation. The charging member applies a charge to the intermediate transfer member to cause an electric field around a region where the image carrying member and the intermediate transfer member contact with each other, where the electric field generates a force for initiating the first transfer operation. The transfer mechanism performs a second transfer operation for transferring the toner image from the intermediate transfer member to a transfer sheet. The discharging member performs a discharging operation for discharging the charge remaining on the intermediate transfer member with contacting the intermediate transfer member after a completion of the second transfer operation. The direct current voltage source applies a direct current voltage to the discharging member to cause the discharging member to perform the discharging operation. The direct current voltage controller controls the direct current voltage in accordance with a volume resistivity of the intermediate transfer member.

Method and apparatus for image forming performing improved cleaning and discharging operation on image forming associated members

Method and apparatus for image forming performing improved cleaning and discharging operations on image forming associated members

An image forming apparatus includes an image carrying member, an intermediate transfer member, a charger, a transfer mechanism, a discharger, a direct current (d.c.) voltage source, and a d.c. voltage controller. The intermediate transfer member faces and contacts the image carrying member carrying a toner image, and receives the toner image therefrom during a first transfer. The charger charges the intermediate transfer member to cause an electric field around where the image carrying member and the intermediate transfer member contact each other, the electric field initiating the first transfer. The transfer mechanism transfers the toner image from the intermediate transfer member to a transfer sheet. The discharger discharges charge remaining on the intermediate transfer member. The d.c. voltage source applies a d.c. voltage to the discharger to cause the discharging. The d.c. voltage controller controls the d.c. voltage in accordance with a volume resistivity of the intermediate transfer member.

An image forming apparatus includes an image carrying member, intermediate transfer member, charger, transfer mechanism, discharger, direct current voltage source, and direct current voltage controller. The intermediate transfer member contacts the image carrying member and receives a toner image therefrom during a first transfer operation. The charger charges the intermediate transfer member to generate an electric field where the image carrying member and the intermediate transfer member contact each other for initiating the first transfer operation. The transfer mechanism performs a second transfer operation to transfer the toner image from the intermediate transfer member to a transfer sheet. The discharger discharges a charge remaining on the intermediate transfer member after completing the second transfer operation by the direct current voltage source applying a direct current voltage to the discharger. The direct current voltage controller controls the direct current voltage based on a volume resistivity of the intermediate transfer member.

An image forming apparatus of the type transferring a toner image from a photoconductive element to a recording medium by way of an intermediate transfer belt is disclosed. Toner images of different colors are sequentially transferred from the photoconductive element to the intermediate transfer belt one above the other, forming a full-color image. When the full-color image is to be transferred from the intermediate transfer belt to a paper or similar recording medium, a secondary transfer belt is brought into contact with the portion of the intermediate transfer belt contacting a secondary transfer roller. As a result, the secondary transfer belt deforms complementarily to the shape of the secondary transfer roller, forming a nip between it and the intermediate transfer belt. In this condition, the secondary transfer belt contacts the intermediate transfer belt evenly and prevents an excessive pressure from acting locally on the toner image existing on the intermediate transfer belt.

Image forming apparatus

A device incorporated in an image forming apparatus for transferring a toner image from a photoconductive element to an intermediate transfer belt and then from the intermediate transfer belt to a sheet or similar recording medium. An electrode member is implemented as a belt drive roller and located at the rear of a portion of the intermediate transfer belt which lies in a position for transferring the toner image from the belt to a sheet. The electrode member has a specific volume resistance of 10.sup.7 .OMEGA.cm to 10.sup.12 .OMEGA.cm.

Image transferring device for an image forming apparatus

The apparatus includes a photoconductive element and a transfer belt, with an electrode or bias applicator located downstream from a nip formed between the photoconductive element and the transfer belt. Upstream from the nip, a roller is provided which can also act as an electrode, or which can be held in an electrically floating state. A bias voltage can be provided to the roller upstream from the nip, with the voltage equal to or less than the voltage applied to the downstream electrode so as form a potential gradient. In addition, the applied voltages can be varied based upon the position of a sheet of paper, or in response to changes in humidity.

Image transferring device and medium separating device for an image

An image forming apparatus includes a photoconductive element and a transfer belt, with an electrode or bias applicator located downstream from a nip formed between the photoconductive element and the transfer belt. Upstream from the nip, a roller is provided which can also act as an electrode, or which can be held in an electrically floating state. A bias voltage can also be provided to the roller upstream from the nip, with the voltage equal to or less than the voltage applied to the downstream electrode. In addition, the applied voltages can be varied based upon the position of a sheet of paper, or in response to changes in humidity.

An image recording apparatus is disclosed which includes an intermediate transfer belt rotatable in a reciprocating motion. Before the belt is rotated back and forth for forming a composite toner image, it is rotated in the opposite direction to the image forming direction. This provides the belt with substantially the same deviation in both the forward movement and the reverse movement. Hence, the apparatus insures desirable images by preventing the individual toner images from being brought out of register due to the deviation of the belt.

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Tokyo, Japan

Hideo Yu