IMAGE FORMING DEVICE BY LASER EXPOSURE

摘要

PURPOSE:To decrease jitters without affecting a sub-scanning direction and to improve image quality by adjusting the writing beam diameter of a laser according to the detected jitter quantity in accordance with a prescribed pattern density. CONSTITUTION:The prescribed patterns for jitter detection are formed on a photosensitive body and the density thereof is sampled at specified time intervals by the clock from a control section 36. The data measured in a measuring section 31 is stored into a memory and is sent to a feedback deciding section 33. A jitter detecting section 32 successively calls the data out of the memory and exactly detects the jitter quantity via a slit. The feedback deciding section 33 determines the feedback quantity in accordance with the determined density and jitter quantity and adjusts the writing beam diameter of the laser via the control section 36. The jitters are decreased in this way and the image quality is improved. The slit width for jitter detection in the sub-scanning direction is set mail to prevent the influence in this direction.