| 摘要 |
PROBLEM TO BE SOLVED: To shorten time required for an operator to wait, and to ensure the stability of image density control by removing, if arises, the possibility that image density controllability may become unstable. SOLUTION: A control means executes calibration such that the sensitivity of an image density detecting means for detecting the density of an image on an image carrier or the density of an image primarily transferred to the surface of an intermediate transfer body is set so that the average output value relative to a non-image part has a predetermined set reference value. The control means executes short calibration such that using detected sensitivity set by the previous calibration, the average output value is obtained from the image density detecting means in an operating time shorter than an operating time taken for the calibration and is recorded in a history recording means. If a difference between the obtained average output value and at least the set reference value exceeds a fixed range or a variation becomes equal to or higher than a specific value, the calibration operation is executed to reset detection sensitivity. COPYRIGHT: (C)2010,JPO&INPIT |
