To obtain a printer in which correspondence between a printed matter and a print section can be discriminated easily by imparting identifier data to the printed matter.

In the printers 10, 50 comprising a plurality of print sections 20 and 60 performing print processing based on specified data and one sheet discharge section for stacking the sheets printed out from respective print sections 20 and 60, control means 30 and 70 control the operation to print on a print sheet based on print data at each print section 20, 60 and to print an identifier onto the print sheet based on identifier data 6 indicative of the print section where printing is performed.