| 摘要 |
PURPOSE:To perform sharp development closely following an original by leaving a very narrow gap between a photosentivie drum and a toner layer; making the peripheral speed of the drum and that of the layer about equal; and specifying the relation between the drum speed and alternating frequency. CONSTITUTION:The gap between photosensitive drum 1 and developing sleeve 2 is held at about 300mum with a roller set at a position independent of the developing face. The thickness of a toner layer is regulated to about 120mum with magnets S3 in sleeve 2, and the toner particles are moved back and forth in the gap with alternating bias power source 7. By making the peripheral speed of sleeve 2 lower than that of drum 1 by 2-6% the speeds become about equal to eliminate such directional properties as makes the toner distribution uneven. Developing speed Vp and alternating voltage frequency f are adjusted so as to satisfy equation I. Thus, occurrence of ground fog is prevented, and a visible image with gradation can be obtained. |
