Patent ID: 9541865
Date: 2017-01-10
CPC Classifications: G03G

Claim:
1. An image forming apparatus, comprising: an image bearer configured to bear a toner image; a transfer device configured to contact the image bearer to form a transfer nip; a transfer bias power source configured to output an output voltage to transfer the toner image from the image bearer onto a recording medium in the transfer nip; and a controller configured to control the transfer bias power source, wherein the transfer bias power source is configured to output the output voltage that alternates between a transfer-directional voltage and a return-directional voltage, to transfer the toner image from the image bearer to the recording medium, the transfer-directional voltage having a polarity to transfer the toner image from the image bearer to the recording medium and the return-directional voltage having an opposite polarity to the polarity of the transfer-directional voltage, and wherein the controller is configured to reduce a frequency of the output voltage as a ratio of A to B decreases, where A is a time period of application of the return-directional voltage within one cycle of the output voltage, and B is a time period of the one cycle of the output voltage.