An image forming apparatus, which charges and exposes a surface of a photosensitive member to form an electrostatic latent image, and develops the electrostatic latent image to form a toner image on the photosensitive member, the image forming apparatus comprising: a photosensitive member driving unit configured to rotate the photosensitive member; a charge unit having an opening portion opposed to the surface of the photosensitive member, the charge unit configured to charge the surface of the photosensitive member; a shield member, which is movable between a closed position at which the shield member closes the opening portion of the charge unit and an open position at which the shield member opens the opening portion; a shield member driving unit configured to move the shield member between the closed position and the open position; and a control unit configured to control the photosensitive member driving unit so that the photosensitive member is rotated in a state in which the shield member is situated at the open position, and that the photosensitive member is prevented from being driven in a state in which the shield member is situated at the closed position, characterized in a position detecting unit configured to detect a position of the shield member, wherein the control unit is configured to determine whether or not the shield member is situated at the open position based on a signal from the position detecting unit, and the control unit is configured to display an error indication on a display unit provided on the image forming apparatus in a case where the control unit cannot determine that the shield member is situated at the open position even when a predetermined time has elapsed after the control unit starts driving the shield member driving unit so as to move the shield member toward the open position. a photosensitive member driving unit configured to rotate the photosensitive member; a charge unit having an opening portion opposed to the surface of the photosensitive member, the charge unit configured to charge the surface of the photosensitive member; a shield member, which is movable between a closed position at which the shield member closes the opening portion of the charge unit and an open position at which the shield member opens the opening portion; a shield member driving unit configured to move the shield member between the closed position and the open position; and a control unit configured to control the photosensitive member driving unit so that the photosensitive member is rotated in a state in which the shield member is situated at the open position, and that the photosensitive member is prevented from being driven in a state in which the shield member is situated at the closed position, characterized in a position detecting unit configured to detect a position of the shield member, wherein the control unit is configured to determine whether or not the shield member is situated at the open position based on a signal from the position detecting unit, and the control unit is configured to display an error indication on a display unit provided on the image forming apparatus in a case where the control unit cannot determine that the shield member is situated at the open position even when a predetermined time has elapsed after the control unit starts driving the shield member driving unit so as to move the shield member toward the open position.