| 摘要 |
PROBLEM TO BE SOLVED: To obtain a developing device capable of simultaneously solving the problems such as deterioration of an image quality due to that a developer is excessly charged or the soiling due to that the developer scatters on the surroundings. SOLUTION: In this developing device 5 provided with a magnet roller (maltipolar permanent magnet) 5b, a developing sleeve (developer carrier) 5a and a doctor blade (control member) 5d, the normal line direction magnetic flux density B (r) by the magnet roller 5b is positioned by the angle formed with regard to a rotary center of the developing sleeve 5a, so that two peaks of the B (r) is within 0 degree to 10 degree with regard to respectively closest position with regard to a photoreceptor drum (image carrier) 1 and the doctor blade 5d, the developing pole S1 is more than 20% larger than the angle between B (r) peak position and the rotary upstream side B (r) half value position, the rotary downstream side B (r) half value position, and the transporting pole S2 has the B (r) peak value of 40 to 70% of the above developing pole S1, the half width is in the range between 45 degree and 60 degree, and the angle formed by the control pole N1 is made to be in the range of 100 degree to 110 degree at the B (r) peak position. |
