| 摘要 |
PROBLEM TO BE SOLVED: To provide a development method and device in an image forming apparatus using a touchdown development system, controlling the toner quantity on a developing roller to be normally within a proper amount, preventing decrease of image density or image density unevenness, and obtaining high-quality image for a long period of time even if the toner charging quantity changes according to environmental conditions. SOLUTION: A DC development bias voltage is changed with maintaining constant the potential differenceΔV between the DC development bias voltage and a toner layer forming DC bias voltage. Calibration is performed using as a target image density a toner layer thickness detecting pattern density consisting of an image density adjusting half density pattern formed on a photoreceptor, or formed on the photoreceptor and transferred to a transfer body. The toner layer is formed on the developing roller by the DC development bias voltage and the potential differenceΔV at that time if the target image density is obtained and by the DC development bias voltage and the potential differenceΔV when obtaining the target image density after re-performing the calibration by changing the potential differenceΔV if the target density is notobtained. COPYRIGHT: (C)2010,JPO&INPIT |
