Patent ID: 8662768

Claim:
An image forming device comprising: a sheet feeding unit capable of selectively feeding recording sheets of a plurality of sizes; a print unit configured to print out images represented by print data on page-by-page basis, the print data including information of designated size of the recording sheets; a control unit configured to control the sheet feeding unit to feed the recording sheets of the designated size and control the print unit to execute printing based on the print data; a first detecting unit configured to detect running out of the recording sheets of the designated size in the sheet feeding unit; and a storing unit configured to store the print data, and configured to temporarily store print data when the print data is printed, the storing unit comprising a volatile memory and a non-volatile memory, wherein, on condition that the first detecting unit detects running out of the recording sheets of the designated size in the sheet feeding unit during printing out of the images, the control unit controls the sheet feeding unit to start feeding the recording sheets of a substitute size which is different from the designated size and controls the print unit to continue printing out of images represented by remaining part of the print data, which was not printed on the recording sheets of the designated size, on the recording sheet of the substitute size, wherein the storing unit stores the remaining part of the print data even after the remaining part of the print data was printed on the recording sheets of the substitute size, the storing unit not storing part of the print data which is printed on the recording sheets of the designated size, wherein when the print data is received by the image forming device, the storing unit stores the received print data in the volatile memory, when the print data, which represents a corresponding image and is stored in the volatile memory, has not been printed on a designated size sheet and has been printed on a substitute size sheet, the storing unit stores the print data in the non-volatile memory different from the volatile memory, and when the print data, which represents the corresponding image and is stored in the volatile memory, has been printed on the designated size sheet, the storing unit deletes the print data from the volatile memory and does not store the print data in the non-volatile memory different from the volatile memory.