| 摘要 |
PURPOSE:To maintain image sharpness and gradation characteristics excellently and continuously by forming a gap between a sleeve surface and the inside wall of a developing device two - five times as large as that between the sleeve surface and a blade, and setting the occupation rate of this gap of 15-25% of the circumference of a sleeve. CONSTITUTION:At the bottom part of the toner containing housing 43 of a developing device 4, a block body 48 is provided; its arc surface 47 is opposed to the surface of a sleeve 41 with a gap gamma three times as large as a set gap alpha between the surface of the sleeve 41 and a blade 44, and the rate of the area l of the gap gamma extending along the surface of the sleeve 41 is set to 17% of the circumference of the sleeve 41. Consequently, when long-time continuous copying operation is carried out by using flocculating single-component magnetic toner, excellent image are obtained without causing a toner blocking and a caking phenomenon. |
