Evaluation method of evaluation apparatus and optical writing apparatus for an optical writing device

摘要

PROBLEM TO BE SOLVED: To improve image quality by making it possible to previously specify the correction place of the light emitting element of an LPH (LED printer head) corresponding to a streak occurrence position, before an optical writing device is incorporated in an image forming apparatus, thereby making it possible to discriminate whether an image quality concern is produced or not and obtaining a chance for taking an action corresponding to the concern.;SOLUTION: An LPH evaluation device lights each light emitting element with a previously set lighting pattern, moves a light receiving part to a position facing the lighted light emitting element, and calculates an MTF (Modulation Transfer Function) value for each light emitting element, based on a signal of light received by the receiving part, a first movement average value for each light emitting element at a previously set first movement average interval, based on the MTF value, a second movement average value for each light emitting element at a second movement average interval, based on the MTF value, and a difference value between the first movement average value and the second movement average value for each light emitting element, to specify the light emitting element to be corrected, based on the difference value and a previously set threshold.;COPYRIGHT: (C)2010,JPO&INPIT