| 摘要 |
PROBLEM TO BE SOLVED: To precisely detect a light quantity in a surface part by obtaining a state where a developing sleeve in a developing unit does not face an image carrier, and adjusting the light quality of a light emitting element in an optical sensor. SOLUTION: The light quantity of a P-sensor 32 is adjusted at the time of applying a power source or during a self-check executed at intervals of a specified time or a fixed number of sheets, for instance. When the self-check is started, the developing unit 13 has the state where the developing sleeve does not face a photoreceptor 2, to make development impossible. After the developing sleeve is placed in a nonfacing position not facing the photoreceptor 2, a voltage based on light reflected from a photoreceptor surface part is adjusted when the light receiving element of the P-sensor 32 is a sensor for converting a received light quantity to a DC current, for instance. After that, the P-sensor 32 detects the reflected light quantity of a multilevel pattern with the adjusted light quantity, for instance, and a developing bias, a potential by electrification and laser light are adjusted to make an image proper density, so that a driving part for supplying toner is controlled. |
