| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a developing apparatus accurately detecting a toner concentration according to aging and to provide an image forming apparatus. <P>SOLUTION: The developing apparatus includes: conveying screws 4 and 5 for stirring and conveying developer W containing toner and carrier; a developing roller 3 that receives developer from the conveying screws 4 and 5; and a toner concentration detection sensor 6 that detects the toner concentration of developer. This developing apparatus is provided with an ultrasonic transducer 8 that vibrates developer W on a measurement target part of the toner concentration detection sensor 6. According to the toner concentration detected by the toner concentration detection sensor 6 or the cumulative time of use of the developing apparatus 1, the vibration frequency of the ultrasonic transducer 8 is changed, thereby changing the intensity of vibration. <P>COPYRIGHT: (C)2009,JPO&INPIT |
