Ricoh Company, Ltd.

Hisashi Fuzisaki

Kenji Karashima

Mayumi Yoshida

Haruji Mizuishi

Yasushi Akiba

A contact type image transferring device and method incorporated in an image forming apparatus for cleaning a residual toner on a transfer roller. The transfer roller is in contact with a photoconductive drum at a first force and forms nip between the roller and the drum. A sheet of paper passes through the nip and a toner image on the drum is transferred to the sheet of paper. When the sheet of paper is not at the nip, the transfer roller is moved such that the force of the roller against the drum is a second force which is different from the first force. A cleaning bias voltage is applied to the roller and toner on the roller is transferred to the drum.

Apparatus and method for cleaning a transfer device of an image forming

A contact type image transferring system and method incorporated in an image forming apparatus for cleaning residual toner on a transfer roller. The transfer roller is in contact with a photoconductive drum and forms a nip between the roller and the drum. A sheet of paper passes through the nip and a toner image on the drum is transferred to the sheet of paper. A power source applies a first bias current which has the same polarity as regularly charged toner to the transfer roller from when the image carrier starts its rotation after an inputting of a print start request until the sheet reaches the nip. Then the power source applies a second bias current having the same polarity as the first bias current to the transferring device when the sheet is at the nip to transfer the toner image on the image carrier to the sheet.

Method for cleaning a transfer device of an image forming apparatus

A contact type image transferring system and method, incorporated in an image forming apparatus, for cleaning a residual toner on a transfer roller. The transfer roller is in contact with a photoconductive drum and forms a nip between the roller and the drum. A sheet of paper passes through the nip and a toner image on the drum is transferred to the sheet of paper. When the sheet of paper is not at the nip, not only a transfer voltage but also a charging voltage is applied at a same time. The polarities of the voltages applied to the charger and to the transfer roller cause the toner on the transfer roller to be removed.

Apparatus for cleaning a transfer device of an image forming apparatus

A contact type image transferring system and method incorporated in an image forming apparatus for cleaning residual toner on a transfer roller. The transfer roller is in contact with a photoconductive drum and forms a nip between the roller and the drum. A sheet of paper passes through the nip and a toner image on the drum is transferred to the sheet of paper at the nip. When the sheet of paper is not at the nip, a first transfer voltage is applied to the transfer roller for 3 to 20 seconds after a paper feed jam is corrected. The polarity of the voltage causes the toner on the transfer roller to be removed. Then a second transfer voltage is applied to the transfer roller which has a polarity which is opposite to the polarity of the first transfer voltage. The voltage difference between the transfer roller and photoconductive drum may be formed by applying bias voltages to both the photoconductive drum and the transfer roller.

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Kawasaki, Japan

Hisashi Fuzisaki