Printer, printing system, and storage medium

A non-transitory recording medium that stores a program that causes a computer to perform a method when installed in a printer that comprises a print unit and a display unit and operates with a rechargeable battery to issue print media, the method comprising:

• computing “A” based on:
• a decrease in remaining battery capacity of the battery during a period of time from a reference time to the present time, and a total number of print media that have been issued during the period of time, where “A” is defined as remaining battery capacity of the battery decreased as a single print medium is issued;
• computing (B−C)/A to obtain a number of print media on which the print unit can print, where “B” is defined as present remaining battery capacity of the battery, and “C” is defined as a lower limit of remaining battery capacity of the battery;
• and
• controlling the printer to, upon determining that a decrease in remaining battery capacity of the battery is greater than a first value in a period of time during which printing is not performed by the print unit, control the display unit to display the number of print media on which the print unit can print with remaining battery capacity of the battery.

A printer for issuing print media, comprising:

• a rechargeable battery configured to supply power to the printer;
• a print unit configured to print information on each of the print media;
• a display unit;
• a cover configured to open or close a container that contains the print medium;
• and
• a control unit configured to:
• compute “A” based on:
• a decrease in remaining battery capacity of the battery during a period of time from a reference time to the present time, and a total number of print media that have been issued during the period of time, where the reference time as a time when the cover is opened, and where “A” is defined as remaining battery capacity of the battery decreased as a single print medium is issued;
• compute (B−C)/A to obtain a number of print media on which the print unit can print, where “B” is defined as present remaining battery capacity of the battery, and “C” is defined as a lower limit of remaining battery capacity of the battery;
• and
• control the display unit to display the number of print media.