| 摘要 |
PURPOSE:To surely form a stable excellent image even at the time of a halftone, by setting conditions similar to the operating conditions of an image forming means immediately after the leading edge section of an original to the leading edge section of the original. CONSTITUTION:The quantity of reflecting light from the surface of an original is detected by means of an optical sensor 1 and, when the frequency of the power supply is 50Hz, the first developing bias value V1 is calculated with a microcomputer 7 at 8-point sampling. Then, the next sampling division is also started in parallel from the 5th point in the course of the first sampling division and the next bias value V2 is calculated at the 8th point. The successive bias values V3, V4... are also calculated in the same manner thereafter. The bias value V2 immediately after the leading edge section of a picture is used as the first developing bias value V1. Therefore, no toner fogging, etc., are produced and excellent images can be formed even if the leading edge section of the picture is in a halftone. |
