Image forming apparatus

An image forming apparatus comprising:

• an image bearing member configured to bear a toner image;
• a transfer member configured to form a transfer portion where the toner image is transferred from said image bearing member onto a transfer material in contact with said image bearing member;
• a moving portion configured to move said transfer member, relative to said image bearing member, to a plurality of positions including a contact position where said transfer member is contacted to said image bearing member to and a separated position where said transfer member is separated from said image bearing member;
• a driving portion configured to drive said moving portion;
• an applying portion configured to apply a voltage to said transfer member;
• a first detecting portion configured to detect at least one of a voltage applied to said transfer member by said applying portion and a current flowing through said transfer member when the voltage is applied to said transfer member by said applying portion;
• and
• a second detecting portion configured to detect a position of said transfer member,
• wherein on the basis of a detection result of said first detecting portion acquired when a first test voltage is applied to said transfer member by said applying portion, said second detecting portion sets a second test voltage, and
• wherein said second detecting portion detects the position of said transfer member on the basis of a detection result of a current value by said first detecting portion acquired when the second test voltage is applied to said transfer member by said applying portion.