| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a residual toner amount detecting device capable of preventing erroneous detection upon detecting toner-empty caused by the transmissivity deterioration of an optical system. <P>SOLUTION: Upon detecting the toner-empty (SP1), the light emitted from a light emitting element is transmitted through a toner chamber by the optical system, and the light that is variable in accordance with the residual toner amount is received by a light receiving element. and when the output of the light receiving element is changed by a prescribed value or more as compared with the output of the light receiving element obtained when detecting the toner empty first (SP2), a threshold Vth is changed (SP3). <P>COPYRIGHT: (C)2009,JPO&INPIT |
