Oki Data Corporation

Masao Isoda

Takao Mizutani

Hirokazu Ando

Masayuki A Suzuki

Akihito Onishi

Tsutomu Yamane

Tutomu Shimoda

A semiconductive roller has an electrically conductive shaft, a roller provided on the shaft formed of silicone rubber with carbon contained therein. The silicone rubber is also added olefin oil and zinc oxide. A method is used for manufacturing a semiconductive roller formed of an electrically conductive shaft. The method includes carrying out a first vulcanization where the semiconductive roller is shaped into a roller and carrying out a second vulcanization where the semiconductive roller is heated at 200&deg; C. for substantially four hours.

Semiconductive roller

A cleaning roller is used for electrostatically attracting residual toner left on a photoconductive drum. The cleaning roller includes a shaft and a member formed on the shaft to cover the shaft. The member has contact portions that lie in a cylindrical plane and a plurality of recesses that are formed in the member and bounded by the contact portions. The contact portions are in contact with the photoconductive drum to attract residual toner left on the photoconductive drum. The recesses hold therein the residual toner attracted to the contact portions. The recesses have openings that lie in the cylindrical plane such that a ratio of the areas of the contact portions to the areas of the openings is in the range from 3:7 to 1:1. The openings of the recesses have effective diameters in the range from 50 to 150 .mu.m if the toner particles have effective diameters in the range from 6 to 9 .mu.m. The cleaning roller includes a metal shaft and a resilient member formed on the metal shaft to cover the metal shaft. The resilient member has an electrical resistance in the range from 5.times.10.sup.6 .OMEGA. to 5.times.10.sup.9 .OMEGA..

Cleaning roller

A method for cleaning an image-forming apparatus. Toner is charged to the first polarity prior to transferring the toner image to the print medium and accidentally inverted from the first polarity to a second polarity opposite to the first polarity during the transfer of the toner image to the print medium. When performing a cleaning operation, a first voltage of a first polarity is applied to at least one of a charging roller and a cleaning roller in contact with a surface of a photoconductor. The surface of the photoconductor is charged to a second voltage. The second voltage has a smaller value than the first voltage and is of the same polarity as the first voltage. Therefore, the toner of the second polarity sandwiched between the charged surface of the photoconductor and the at least one of the charging roller and cleaning roller is inverted in polarity, i.e., from the second polarity to the first polarity by triboelectric charging. If the first voltage is applied to the cleaning roller, the photoconductor may be charged to the second voltage by a transfer device or by a charging device. Alternatively, if the first voltage is applied to the charging roller, the photoconductor may be charged to the second voltage by a cleaning device or by the transfer device.

Method of cleaning residual toner from drum and rollers of image forming

A method of manufacturing a developing roller includes two steps. First, a grinding wheel is moved along the length of a developing roller which has been subjected to a secondary vulcanization. The grinding wheel is brought into contact with the developing roller and is caused to rotate so as to perform an abrasive finishing on the surface of the developing roller. Second, a buffing member is moved along the length of the developing roller. The buffing member is in contact with the developing roller and is moved in the peripheral direction of the developing roller so as to perform buffing on the surface of the developing roller.

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Tokyo, Japan

Masao Isoda