| 摘要 |
PROBLEM TO BE SOLVED: To accurately adjust toner adhesive amount by a method in which toner consumption is restrained to be low in a shorter time without performing procedure such as the formation of many patches and linear approximation in the conventional manner. SOLUTION: An infrared diffused reflected light type sensor having linear characteristic in a control range is used as a toner adhesive amount sensor on a photoreceptor, and the sensor is calibrated before control operation (S31). The present set value VB0 of developing bias is stored, a test patch image is formed at the set value VB0, and respective detection outputs Vsc and Vsgc on the test patch and the adhesive amount 0 are obtained by the adhesive amount sensor (S33 and 34). Toner adhesive amount=proportional coefficient×(Vsc-Vsgc) and ΔVB=proportional coefficient×(Vsc-Vsgc-VsA) are effected from the linear characteristic (ΔVB: the deviation amount of developing bias from target adhesive amount, and VsA: a target adhesive amount corresponding value), so that ΔVB is calculated based on relation (S36) and the bias is adjusted (S37) by setting VB0+ΔVB. |
