| 摘要 |
PURPOSE:To obtain a sharp developed image of high picture quality having no irregularity in density by providing a leveling plate whose critical surface tension is set below a specific value on the downstream side of a control blade and on the slightly upstream side of a development position. CONSTITUTION:An image carrier 1 and a sleeve 2 rotate as shown by arrows and the sleeve 2 is applied with an AC bias 13 on which a DC is superposed. A developer 10 consisting of a mixture of toner and magnetic carriers is held and carried on the sleeve 2 by magnetic poles N3 and S2 and controlled by the blade 6 to proper layer thickness. Then the surface of the developer layer is leveled by the leveling plate 7. Here, the leveling plate 7 abuts on the developer layer with its gravitational turning force around a rotating shaft 8 and the surface of the leveling plate 7 which contacts the developer layer is coated with 'Teflon(R)' whose critical surface tension is low. Then the critical surface tension of the part of the leveling member 7 which contacts the developer layer is set to <=31 dyne/cm. Consequently, the surface of the developer layer is formed uniformly and an image of high picture quality having no density irregularity is formed.
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