PRINTER SYSTEM

PROBLEM TO BE SOLVED: To obtain a printer system in which the sheet size can be recognized accurately and printing can be carried out in optimal format depending on the sheet size. SOLUTION: The printer system 10 comprises an ink jet printer 12 and a PC 14. The ink jet printer 12 executes printing according to designation from the PC 14. When a mode for recognizing the sheet size automatically (automatic sheet recognition mode) is set by the PC 14, an automatic sheet recognition command is transmitted to a CPU 16 following to a print start command. In response to the automatic sheet recognition command, the CPU 16 designates a control circuit 20 to take out a sheet, detect the length of the sheet based on the output from a second sensor 28 and then detect the width of the sheet based on the output from a first sensor 26. The CPU 16 transmits the size data of detected length and width of the sheet to the PC 14. The PC 14 sets an optimal format for the print data depending on the size data before transmitting the print data to the ink jet printer 12.