Image forming apparatus and toner concentration controlling method

摘要

The image forming apparatus and toner concentration controlling method relates to a developing device that holds a two-component developer, a detecting unit that outputs (S3) a reference output value V t0 and (S7,S8) a second output value V t1 , V t2 when the two-component developer is stirred and carried at a stirring and carrying speed corresponding to a second image forming mode, a stirring/carrying member that stirs and carries the two-component developer, and a controlling unit that controls (S9,S10) the toner concentration based on the reference output value V tref and corrected output value V t obtained by correcting (S5,S50) any former output value.