| 摘要 |
PURPOSE:To efficiently suck the powder smoke of developer in full by providing plural suction ports in accordance with the various different circumstances of the existence of the powder smoke of developer and making the aperture areas of the respective suction ports different. CONSTITUTION:A 1st ventilation path is formed between a 1st developing device 3 and a 2nd electrostatic charger 4, and the 1st suction port 9a is provided at the top of the 1st ventilation path and its aperture surface is proximately opposed to the surface of a photosensitive body 1. A 2nd ventilation path is formed between the 2nd charger 4 and a 2nd developing device, and the shape of cross section of the 2nd ventilation path in a direction vertical to the rotary shaft direction of the drum 1 is like a horn whose width gets wider closer to the top. The 2nd suction port 9b is provided at the top of the 2nd ventilation path and its aperture surface turns toward the developing part of the 2nd developing device under the port 9b. The aperture area of the port 9b is made larger than that of the port 9a. |
