In the page printer of this invention, a sheet is discharged and an error occurrence is displayed on a display unit when an over-run error occurs during a printing operation. Subsequently, the print data of the 1/n portion of the page which was being converted to dot image data at the error-occurrence time is developed into dot image data and stored into a RAM together with an error-occurrence position. The print data is re-converted to the dot image data and printed. When the printing operation reaches the error-occurrence position stored in the RAM, the dot image data stored in the RAM is transmitted to a video RAM, and the printing operation is continued. Therefore, this page printer can automatically carry out the re-printing operation when an over-run error occurs.