A mode control system is provided for a printer having an internal battery. The mode control system selects at least a charge operation for charging the battery and a printing operation for printing an image on a recording sheet fed into the printer. The mode control system also includes a manually operable member. A duration of an operation of the manually operable member is detected, and one of the charge operation and the print operation is selected in accordance with the duration of the operation of the manually operable member.