| 摘要 |
PROBLEM TO BE SOLVED: To obtain a developed image of high quality by making the sufficient application of a charge to magnetic toner on a developing sleeve compatible with the selective coating of the sufficiently charged toner, in a restricting region where a line of magnetic force formed by a magnet in the developing sleeve and a magnet in the regulating sleeve concentrates. SOLUTION: The magnetic pole N1 of the magnet 10 in the developing sleeve 1 and the magnetic pole S1 of the magnet 11 in the regulating sleeve 2 are installed in the vicinity of a part where the developing and regulating sleeves 1 and 2 face each other, to be arranged in a part nearer to the upstream side in the carrying direction of the magnetic toner than a straight line (g) that links the centers of the developing and regulating sleeves 1 and 2. When the half-value width angle of the magnetic flux density distribution of the magnetic pole N1 is defined asα, angles formed by the magnetic poles N1 and S1 with the straight line (g) are defined asθandϕrespectively and the radii of the developing and regulating sleeves are defined as R and r, an equation (1): 0<θ<=α/2 and an equation (2): 0<=r.sinϕ<=R.sinθare satisfied. |
