| 摘要 |
PURPOSE:To cope with a wide range of needs such as a variety of originals and picture qualities by developing an electrostatic latent image formed on a photosensitive body by two types of magnet rolls. CONSTITUTION:A developing sleeve 102 is disposed with a development gap of 0.5 mm, by facing a photosensitive drum 104. A +250 V bias is impressed on the developing sleeve 104, and which rotates in the direction of an arrow B at a peripheral speed of 120 mm/S. A developing sleeve 107 is disposed with a development gap of 1.0 mm, by facing the photosensitive drum 104. A +200 V bias is impressed on the developing sleeve 107, which rotates in the direction of an arrow B2 at a peripheral speed of 240 mm/s. Thus such a developing characteristic can be attained that a line image sharply rises from an original at a low density, while a solid image slowly rises after its original density becomes slightly high, and both of them in terms of parts at high original densities coincide with each other at high density, and therefore the need of a wide range of picture qualities can be met.
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