Image forming apparatus for applying pressing force acting between cleaning member and belt

An image forming apparatus comprising:

• a belt;
• a cleaning member disposed in confrontation with the belt and having a predetermined width;
• a backup member that is disposed to pinch the belt in cooperation with the cleaning member, a width of the backup member being narrower than the width of the cleaning member;
• a pressing mechanism that is configured to press the backup member to the cleaning member for applying a pressing force acting between the cleaning member and the belt;
• a pressing-force changing mechanism that is configured to change the pressing force acting between the cleaning member and the belt in a state in which the cleaning member is in contact with the belt;
• and
• a control unit that controls the pressing-force changing mechanism to change the pressing force,
• wherein the pressing-force changing mechanism comprises:
• a plurality of pivoting members each having a pivoting end;
• a plurality of urging members that is provided at respective ones of the plurality of pivoting members and that is configured to urge the pivoting end of the respective ones of the plurality of pivoting members;
• and
• a cam member that is provided for at least one of the plurality of pivoting members, the cam member having a large diameter part and a small diameter part, the cam member being configured to prohibit a corresponding one of the plurality of urging members from applying an urging force to the cleaning member when the large diameter part contacts the pivoting end of the at least one of the plurality of pivoting members, the cam member being configured to allow the corresponding one of the plurality of urging members to apply an urging force to the cleaning member when the small diameter part confronts the pivoting end of the at least one of the plurality of pivoting members.