PURPOSE: To increase speed of printer by starting feed of second paper before a resist sensor is turned OFF by means of a first paper, and in the case of size error of the first paper, releasing error and feeding second paper which is stopping.

CONSTITUTION: In a printer having a paper error judging function, time (t) elapsed after turning ON of a resist clutch is compared with an intermediate time (t3) selected according to the size set in step 67 even if the resist sensor is not turned OFF. If the resist sensor is not turned OFF even if t>t3, it is judged to be paper size error in step 66. Second paper is fed before the resist sensor is turned OFF by the first paper, and the first paper is discharged if paper size error is detected. The second paper turns a feed clutch OFF to stop carriage of paper between paper feed start position and the resist sensor, then error is released and paper feed is resumed.