| 摘要 |
PROBLEM TO BE SOLVED: To provide a vertical circulation system developing device which is excellent in the uniform mixing property of supply toner and which is consti tuted so that toner concentration in the device is stabilized in a short time after the toner is supplied and the density irregularity of an image is effectively prevented from occurring when the toner is supplied. SOLUTION: A developing sleeve 5 incorporating a magnet and a 1st developer stirring and feeding mechanism 16 feeding developer are housed in a lower chamber 3 formed in a developing housing 1. A 2nd developer stirring and feeding mechanism 17 feeding the developer in the direction opposite to the feeding mechanism 15 is housed in an upper chamber 4. Then, the chambers 3 and 4 are made to communicate with each other at front end parts in the feeding directions by the respective developer stirring and feeding mechanisms. Then, a magnet roller 25 drawing up the developer to the chamber 4 from the chamber 3 is arranged at the communication part being the front end part in the feeding direction by the feeding mechanism 16. Besides, a toner supply port 30 is formed at the end part of the chamber 4 communicating with the communication part. |
