| 摘要 |
PURPOSE:To prevent the void of image by constituting a common casing wall to adjacent developing devices by a partition wall radially extending from the peripheral wall of a hollow member communicating with the outside and forming the hollow member and the partition wall of a heat conductive material. CONSTITUTION:A developing unit is provided with the partition wall installed between front and back disk-like end plates, and the partition wall is constituted of a hollow cylinder part 82 into which a cylindrical black toner bottle housing black toner can be inserted and developing unit easing parts 83, 83C, 83M and 83Y radially extending from the outer periphery of the cylinder part 82 communicating with the outside at the front end wall of the developing unit and dividing space around the cylinder part 82 to four developing chambers having nearly the same shape each other in a circumferential direction. The cylinder part 82 and the casing parts 83, 83C, 83M and 83Y are formed of the material excellent in heat conductivity such as aluminum as an integrated substance. Thus, the hollow cylinder part is utilized as a part of the peripheral wall of the developing chamber and heat exchange between outside air on the outside of the developing chamber and air on the inside of the developing chamber is performed through the peripheral wall part. |
