JPS6468777A - Developing device - Google Patents

Abstract

PURPOSE:To form a superior image without varying the conveyance amount of a developer even if the main pole of an internal magnet shifts in position by providing a nap height control plate which is displaced in correspondence to the angular displacement of the main pole of a magnet roller facing the surface of an image formation body. CONSTITUTION:One end of the nap height control plate 4 is fixed to the shaft 14 of the magnet roller by a coupling member 11a and the other end is supported rotatably by a developing sleeve shaft 13 through a bearing 12 and rotates by the same angle as the adjustment rotational angle of the magnet roller 3 while having a constant control gap P with a developing sleeve 2. Therefore, the main pole N1 and nap height control plate 4a are only set previously and then when the main pole is moved to a position N2 by varying the main pole angle by delta, the nap height control plate rotates similarly by delta to move a position 4b, but the position relation between the nap height control plate and main pole does not change. Consequently, even if the main pole angle of the magnet roller varies, the constant conveyance amount of the developer is obtained.