| 摘要 |
PROBLEM TO BE SOLVED: To surely prevent the occurrence of a trouble that no image is outputted in image forming processing by accurately detecting a state in which a developing device which is not filled with developer is attached to an image forming apparatus by using only an existing functional part and a detecting means or the like in the image forming apparatus. SOLUTION: In the developing device 5 freely attachable/detachable to/from a printer 1, comparison is made for oscillation frequency outputted from a detection sensor 11 in accordance with toner concentration in the developer stored in a developing tank 52 before and after the stirring operation of the developer D by the rotation of a stirring blade 54 over a specified period after attaching the developing device 5, and it is discriminated that the developer is not stored in the attached developing device 5 when a difference between them is less than a specified value, so that warning is generated. COPYRIGHT: (C)2003,JPO |
