Patent ID: 9645530
Date: 2017-05-09
CPC Classifications: G03G

Claim:
1. An image forming apparatus, comprising: an image bearer to bear a toner image; a transfer device contacting the image bearer to form a transfer portion; and a transfer bias power source to output a transfer bias to transfer the toner image from the image bearer to a recording medium at the transfer portion, the transfer bias being a superimposed bias including a direct current (DC) component and an alternating current (AC) component that cyclically alternates between a transfer-directional bias to transfer the toner image from the image bearer to the recording medium and an opposite-directional bias in an opposite direction of the transfer direction, a controller to control the transfer bias power source to output the transfer bias, wherein a ratio of a time period of application of the opposite-directional bias to a total time period of one cycle of the AC component of the superimposed bias is greater than 50%, wherein a ratio of a value of the DC component of the superimposed bias output within a region ranging from a leading end of the recording medium to a predetermined length to a value of the DC component of the superimposed bias output outside the region is greater than a ratio of a value of the AC component of the superimposed bias output within the region to a value of the AC component of the superimposed bias output outside the region.