ELECTROPHOTOGRAPHIC DEVELOPING DEVICE

PURPOSE:To obtain sharp images without causing the disorder of the images nor variance in density by agitating dry toner stored in a developing container with an air flow passing through the container, and carrying out development while holding the toner fluid. CONSTITUTION:A developing sleeve 3 which includes a fixed magnet assembly body 4 is arranged rotatably at the exit-side opening of the developing container 1 opposite a photosensitive drum 2, its lower bottom wall is formed of a porous material plate 5, and a low-pressure dry air flow is sent into the container 1 by an air blowing mechanism 10 arranged below the porous plate 5. The mechanism 10 consists of an air feed fan 11, a dehumidifying filter 12, and a guide part 13 and the air flow sucked by the fan 11 is dehumidified and then guided to below the porous plate 5 through the guide 13. The revolutions per minute of the fan 11 is varied on the basis of a control signal from a sensor 7 which is arranged in the container 1 and detects the height of deposit of toner 6. Thus, the toner is held in a homogeneous fluid state to eliminate the disorder of an image and variance in its density.