IMAGE FORMING APPARATUS

PROBLEM TO BE SOLVED: To provide an image forming apparatus, capable of appropriately recovering a single-component developer on a developing roller and replacing the single-component developer on the developing roller with a new single-component developer. SOLUTION: The image forming apparatus with a developing device 7, which comprises a developer housing part 71, a developing roller 72, a doctor blade 73 and a toner supply roller 74, is provided with: a detection sensor 2 for detecting that a medium to be transferred having the size less than a predetermined size passes through a paper-feed path for the medium to be transferred, to which the toner from the developing device 7 is transferred; and a control means 3 for changing the application bias to the toner supply roller 74, after ending image formation to the medium to be transferred, when the detection sensor 2 detects that the size of the medium to be transferred is less than the predetermined size. COPYRIGHT: (C)2010,JPO&INPIT