Image forming apparatus having spacing roller for maintaining uniform spacing between image bearing member and developing material supplying means

摘要

An image forming apparatus has an image bearing member rotatable in a specified direction, a developing roller for supplying developing material to a latent image formed on the image bearing member, a spacing roller rotatably supported on a shaft of the developing roller and making contact with the edge of the image bearing member in the axial direction, and a seal member having a portion that contacts the image bearing member on the upstream side of the developing roller in the direction of rotating and a portion that contacts the image bearing member on the developing roller side. The spacing roller forms the desired developing gap between the surface of the developing roller and the surface of the image bearing member. The seal member sweeps the surface of the image bearing member so as to mainly prevent the adhesion to the spacing roller of the airborne toner which is in the vicinity of the surface of the image bearing member and the surface of the developing roller. Further, the toner adhering to the surface of the image bearing member is cleaned therefrom by the seal member before the toner reaches the spacing roller. Thus, the precision of the developing gap can be maintained in the desired condition over a long period of time.