| 摘要 |
In an electrophotographic image forming apparatus having a toner image forming device, an image transfer device includes an image transfer roller for transferring the toner image to a sheet in an image transferring operation. At least two sheet feeding devices feed and convey a sheet to the image transfer device, at least one of the feeding devices having a sheet width sensor. A power supply applies a bias to the image transfer device and a control device controls the application of the bias so as to remove toner on said image transfer roller between image transferring operations. The control device applies the bias for a predetermined time, or with a predetermined voltage, when it has received a signal indicative of a width of the sheet conveyed to the image transfer device and applies the bias for a longer time, or with a higher voltage, when it has not received a signal indicative of a width of the sheet conveyed to the image transfer device.
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