Image forming apparatus

An image forming apparatus comprising:

• a manual feeding tray;
• a detecting portion configured to detect whether or not a sheet is put on said manual feeding tray;
• an image forming portion configured to form an image on the sheet fed from said manual feeding tray;
• a first rotatable member;
• a second rotatable member configured to form a nip, for fixing the image on the sheet, in cooperation with said first rotatable member;
• a pressing mechanism configured to press said first rotatable member toward said second rotatable member;
• a moving mechanism configured to move said pressing mechanism between a first position where the nip is formed by said first and second rotatable members and a second position where a force applied between said first and second rotatable members by said pressing mechanism is smaller than that when said pressing mechanism is in the first position;
• a control unit configured to control an operation of said moving mechanism;
• and
• a receiving portion configured to receive input of an instruction about an image forming operation for forming the image on the sheet by said image forming portion,
• wherein said image forming apparatus is capable of selectively executing one of operations in a plurality of modes including a first mode in which said control unit is in a rest state and a second mode in which electric power is supplied to said control unit, and
• wherein said image forming apparatus changes the mode of the operation to the second mode of the operation in response to detection of putting of the sheet on said manual feeding tray during execution of the operation in the first mode with said pressing mechanism being in the second position, and
• then in response to receipt of input of a predetermined instruction about the image forming operation by said receiving portion during execution of the operation in the second mode, said control unit controls said moving mechanism so that said pressing mechanism moves from the second position to the first position.