A printing apparatus comprising: a printing unit configured to print received information on a recording sheet; a power supply including a rechargeable battery; a charger, coupled to the power supply, and configured to charge the rechargeable battery, wherein the charger includes a charging circuit, a setting circuit configured to receive a feedback voltage from the rechargeable battery and a charging voltage from the charging circuit, and a first switch coupled to the charging circuit; a second switch; and a diode coupled in parallel to the second switch, wherein the second switch and the diode are coupled to the rechargeable battery, wherein, in a state where the feedback voltage from the rechargeable battery is supplied to the setting circuit, the setting circuit closes the first switch, the voltage from the rechargeable battery causes a reverse voltage to be applied to the diode, and the voltage from the rechargeable battery causes a forward voltage to be applied to the second switch and close the second switch, to supply power from the rechargeable battery to the printing unit, and wherein, in a state where the charging voltage from the charging circuit is supplied to the setting circuit, the setting circuit opens the first switch, the charging voltage from the charging circuit causes a forward voltage to be applied to the diode, and the charging voltage from the charging circuit causes a reverse voltage to be applied to the second switch and open the second switch, to charge the rechargeable battery by a current flowing through the diode and supply no power from the rechargeable battery to the printing unit. a printing unit configured to print received information on a recording sheet; a power supply including a rechargeable battery; a charger, coupled to the power supply, and configured to charge the rechargeable battery, wherein the charger includes a charging circuit, a setting circuit configured to receive a feedback voltage from the rechargeable battery and a charging voltage from the charging circuit, and a first switch coupled to the charging circuit; a second switch; and a diode coupled in parallel to the second switch, wherein the second switch and the diode are coupled to the rechargeable battery, wherein, in a state where the feedback voltage from the rechargeable battery is supplied to the setting circuit, the setting circuit closes the first switch, the voltage from the rechargeable battery causes a reverse voltage to be applied to the diode, and the voltage from the rechargeable battery causes a forward voltage to be applied to the second switch and close the second switch, to supply power from the rechargeable battery to the printing unit, and wherein, in a state where the charging voltage from the charging circuit is supplied to the setting circuit, the setting circuit opens the first switch, the charging voltage from the charging circuit causes a forward voltage to be applied to the diode, and the charging voltage from the charging circuit causes a reverse voltage to be applied to the second switch and open the second switch, to charge the rechargeable battery by a current flowing through the diode and supply no power from the rechargeable battery to the printing unit.