| 摘要 |
<P>PROBLEM TO BE SOLVED: To carry out stable circular conveyance of developer while maintaining image quality and performances such as durability and miniaturization, in a developing device equipped with three developer conveyance passages having separate developer supply, recovery and stirring functions and an image forming apparatus. <P>SOLUTION: The developing device is equipped with a supply conveyance passage 105 with a supply screw 104 which supplies developer to a developing roller under conveyance, a recovery conveyance passage 108 with a recovery screw 107 which recovers developer after development from the developing roller and conveys it in the same direction as the supply screw, and a stirring conveyance passage 109 with a stirring screw 108 which receives supply of surplus developer in the supply conveyance passage and recovered developer in the recovery conveyance passage and conveys these under stirring in the reverse direction to the supply screw, wherein the recovery conveyance passage is located above the stirring conveyance passage in the direction of gravitation force so that recovered developer is supplied to the stirring conveyance passage by free fall, wherein a recovered developer supply opening 114 in the recovery screw 107 becomes broader as proceeding to the downstream end of the recovery conveyance passage. <P>COPYRIGHT: (C)2008,JPO&INPIT |
