| 摘要 |
PURPOSE:To control gradation according to the change of a laser beam diameter by deciding gradation correction data according to the detected laser beam diameter and detected toner concentration. CONSTITUTION:Since a gradation characteristic receives the effect of the beam diameter, the beam diameter is measured together with the characteristic of a photosensitive body and the gradation correction data is decided by using the measured value. That means, the potential VB of a developing bias and the voltage VG of a grid are decided from AIDC levels(LBA) obtained based on the attached quantity of the toner detected by an AIDC sensor by a prescribed AIDC table according to the respective AIDC levels. Then, the efficiency of developing is adjusted. Besides, a (gamma) correction table number showing the gradation characteristic is decided by the AIDC table according to the measured beam diameter. On the other hand, a (gamma) kind (N=1 to 6) is decided by a beam diameter table based on the measured beam diameter. Then, a (gamma) correction table is decided based on the (gamma) correction table number and the (gamma) kind (N). |
