Printer and method for operating the same

A printer comprising:

• a discharge unit;
• a first printing unit disposed along a sheet conveying path extending from the discharge unit and configured to print an image on a first sheet while the first sheet is conveyed from the discharge unit to the first printing unit and then to the discharge unit;
• a second printing unit disposed farther from the discharge unit than the first printing unit along the sheet conveyance path and configured to print an image on a second sheet while the second sheet is conveyed towards the discharge unit therethrough, using a printing method that is different from a printing method of the first printing unit;
• a data storage that stores data including one-bit data indicating whether or not the first printing unit is in use and one-bit data indicating whether or not the second printing unit is in use;
• and
• a controller configured to determine whether or not each of the first and second printing unit is in use by referring to the data, and control only one of the first and second printing units to print, based on the determination.