| 摘要 |
PURPOSE:To attain the sure separation of a transfer material by measuring the exposure time of a specified width in the leading edge part of an image forming area on an image carrier and controlling a developing bias based on the measured result. CONSTITUTION:A counter 13 measures the light emitting time of a laser 12 so as to store it in a memory 14. When the emission of a laser light of a specified width in the leading edge part of the transfer material is completed, a correction circuit 16 computes the light emitting time per unit length in an axis direction in the image area on a sensitive drum based on the light emitting time from the memory 14 and a paper size signal from a controller 15 so as to store in a memory 17. Based on the contents of the memory 17, the controller 15 outputs a control signal to a developing bias impression circuit 4b through a high voltage transformer control circuit 18 so as to control the developing bias. Thus, the adhesion quantity of toner is increased and the failure in the separation of the transfer material does not occur so much even if a printing ratio is low in the leading edge part of the transfer material. |
