| 摘要 |
PURPOSE:To prevent the occurrence of the sticking of toner and a carrier by successively and repeatedly forming the latent images of plural different reference patterns for controlling a toner concentration on a toner carrier at equal intervals, plural times. CONSTITUTION:The latent images of plural different reference patterns for controlling the toner concentration (P-pattern), are successively and repeatedly formed on a photosensitive drum 11, at equal intervals, plural times. The reference pattern for controlling the toner concentration is composed of reference patterns 1 and 2, for instance. When the toner concentration is detected, the latent image of the reference pattern for controlling the toner concentration is formed on the photosensitive drum 11, and developed with a two-component developer by a developing unit, to obtain an actual image, and the density of the actual image is optically detected by an optical type sensor 18. At this time, the reference patterns 1 and 2 are alternately formed on the photosensitive drum 11. Therefore, a variation in the result of the detection caused by a difference in the toner concentration and a change in a toner electrifying quantity while the developer is stirred, is averaged and the toner concentration can be accurately controlled. |
