| 摘要 |
PURPOSE:To enable image formation with an always adequate density by transiently stopping an image forming operation when a toner concn. falls below a prescribed permissible level than a target set level. CONSTITUTION:Light P corresponding to an original (a) is exposed on a photosensitive drum 1 by an optical system. Paper (b) in a paper feed cassette 16 is conveyed by a feeding means 19 toward an image forming part 7 and a toner in a toner bottle 22 is replenished by a toner replenishing means 3 into a developing device 3. The toner concn. is detected by an ATDC sensor 24 and the replenishing means 13 is so controlled that the toner concn. attains the target set level. Control is so executed as to interrupt the paper feeding with the feeding means 19 and to transiently stop the image forming operation when the toner concn. falls below the preset permissible level set at the prescribed level lower than the target set level. The image having always the adequate density is thus formed on the paper. |
