| 摘要 |
<P>PROBLEM TO BE SOLVED: To detect the abnormality of a developer recovering and discharging mechanism which may occur in the prior stage of the failure of a developing device main body, particularly in a developing device provided with the developer recovering and discharging mechanism. <P>SOLUTION: The developing device which is configured in such a manner that a developer carrier 3 is disposed to face an image carrier 1, a developer circulating and conveying path 4 capable of circulating and conveying developer is provided on the back of the developer carrier 3 and a stirring and conveying member 5 capable of stirring and conveying the developer is disposed in the developer circulating and conveying path 4, includes: a developer replenishing mechanism 6 which replenishes new developer to the developer circulating and conveying path 4; a developer recovering and discharging mechanism 7 which is provided in a part of the developer circulating and conveying path 4 and gradually discharges a surplus of the developer in the developer circulating and conveying path 4; a concentration detecting means 8 which detects the toner concentration of the developer in the developer circulating and conveying path 4; and an abnormality judging means 9 which judges the abnormality of the developer recovering and discharging mechanism 7, based on information from the concentration detecting means 8 and the information of the amount of the developer replenished by the developer replenishing mechanism 6. <P>COPYRIGHT: (C)2007,JPO&INPIT |
