Patent ID: 8068755

Claim:
An image forming apparatus comprising: a belt member; a first image bearing member; a first transfer member arranged to form a first transfer portion that transfers a toner image formed on the first image bearing member onto the belt member; a second image bearing member that is disposed at a certain position so that the first and second image bearing members are adjacent to each other; a second transfer member arranged to form a second transfer portion that transfers a toner image formed on the second image bearing member onto the belt member; an execution unit arranged to execute a first step of determining a value of a first transferring voltage to be applied to the first transfer member, the first transferring voltage being used to transfer the toner image onto the belt member by applying a voltage to the first transfer member, and a second step of determining a value of a second transferring voltage to be applied to the second transfer member, the second transferring voltage being used to transfer the toner image onto the belt member by applying the voltage to the second transfer member; and a control unit arranged to control execution timing of the first and second steps so that a region of the belt member corresponding to the first transfer member to which the voltage is applied in the first step does not overlap a region of the belt member corresponding to the second transfer member to which the voltage is applied in the second step.