| 摘要 |
PROBLEM TO BE SOLVED: To always form a satisfactory image without the occurrence of carrier- sticking, toner-scattering and a fogged image, etc., irrespective of an environmental fluctuation by measuring the environment near an image carrier and adjusting a developing gap based on the measurement output. SOLUTION: A tap is formed in the center of a stay 17, and a screw 19 is installed in the tap and the tip part of the screw comes into contact with a developing device 4. The trailing end part of the screw 19 is a gear so as to be engaged with a gear 20 fixed to the rotary shaft of a motor 21 attached to the stay 17. The motor 21 is rotated by a signal from a control part 6 and the screw 19 is rotated through the gear 20. In accordance with the rotation of the screw 19, the developing device is moved in a direction shown by an arrow, then, the developing gap Gg is made variable. In the case of narrowing the developing gap Gg, the concentration of developer lying between the photoreceptor 1 and a developing sleeve 4a is increased, then, a developing performance is enhanced, and on the other hand, in the case of enlarging the developing gap Gg, the developing performance is reduced. |
