| 摘要 |
PURPOSE:To shorten FCOT by using a different criterion for patch display for the first copy from that for the second and subsequent copies. CONSTITUTION:A control portion 43 compares a patch density signal given from an A/D convertor 47 with a first threshold X1 stored on a threshold table 55. The first threshold X1 is exclusively for the first copy and greater than a normal threshold (second threshold X2). For the first copy, rotation of a photoreceptor drum 20 is slow so that the amount of electrification by a charged electrode 21 increases, generally resulting in density enhancement; to prevent the density from being enhanced, i.e., to make the density equal to that for the second and subsequent copies, the threshold X1 is made greater so that the amount of supply of toner is reduced. For the first copy, copying operation is therefore started before the photoreceptor drum 20 reaches a constant rate, and so FCOT is shortened. |
