PRINTER, PRINTING SYSTEM, AND BOTH-FACE PRINTING MANAGING METHOD

PROBLEM TO BE SOLVED: To make the relation between the front surface and the rear surface of a page that are reprinted after an error, similar to the state before the error, in a printer, a print system and a both-face print managing method. SOLUTION: This printer is provided with a receiving part 10, which receives print data that is sequentially sent from a print requesting device, a print data expanding part 11 which expands receives print data in each page into a print format, a print mechanism part 12, which both-face-prints the expanded print data and also an automatic page feed mechanism and performs both-face printing. In such cases, a surface heading print data page number that a page number of print data where heading data is printed on the surface of a sheet in a page of the print data in each page to a sheet on which print is completed is head, and when an error occurs, the residing of the print data is received form the print data of the latest surface heading data page number and printing is resumed.