Image forming apparatus

An image forming apparatus comprising:

• a drum unit including a photosensitive drum on which a toner image is formed, and detachably attached to an apparatus main body;
• a transfer roller which transfers the toner image from the photosensitive drum to a medium;
• a fixing device provided on an upstream side of the drum unit in a draw-out direction of the drum unit, and configured to heat-fix a toner image on the medium passing through a pressurized area formed between a heating member and a pressing member;
• a shutter provided to be movable between an opening position for exposing the heating member and a closing position for covering the heating member;
• an opening/closing interlocking part configured to move the shutter to the opening position when the drum unit is attached to an attachment position of the apparatus main body, and to move the shutter to the closing position when the drum unit is drawn out from the attachment position;
• and
• a pressing interlocking part configured to move one of the heating member and the pressing member in a direction of pressing it against the other to bring the pressurized area into a pressure increased state when the shutter is moved to the opening position, and to move one of the heating member and the pressing member in a direction of separating it away from the other to bring the pressurized area into a pressure decreased state when the shutter is moved to the closing position,
• the pressing interlocking part includes:
• an actuator configured to be rotatable around an axis;
• an eccentric cam configured to be rotatable together with the actuator around the axis while in contact with one of the heating member and the pressing member;
• a drive part rotating the actuator and the eccentric cam around the axis;
• and
• a detection part arranged on the same axis as the actuator, configured to be rotatable separately from the actuator in conjunction with the shutter and to detect the actuator, wherein
• in a case where the fixing device is performing a fixing operation, the drum unit is attached to the attachment position, the shutter is moved to the opening position, the detection part is held at a first detection angle, and the drive part holds the actuator at a standard angle, so that the detection part held at the first detection angle detects the actuator, and the eccentric cam is held at a pressure increasing angle to bring the pressurized area into the pressure increased state, and
• in a case where a conveyance failure of the medium occurs in the fixing device performing the fixing operation, when the drum unit is drawn out from the attachment part, the shutter is moved from the opening position to the closing position, the detection part is rotated to a second detection angle separated from the actuator held at the standard angle, and the drive part rotates the actuator from the standard angle to an emergency angle, so that the detection part held at the second detection angle detects the actuator, and the eccentric cam is rotated from the pressure increasing angle to a pressure decreasing angle to bring the pressurized are into the pressure decreased state.