PURPOSE: To enable easy removal of a jammed sheet, by a method wherein duplicator is provided with a means, which displays the position of all papers in the middle of conveyance when conveyance motion is stopped due to jam, and a means which displays the position of a paper by which jam is caused.

CONSTITUTION: Liminar LEDs 32 and 33 are located on both sides of a numeral display unit formed with LEDs 30 and 31 to represent the side view of a duplicator body. The LEDs 30 and 31 for displaying numerals correspond to a duplicator body, the LED32 to a feed display cassette, and the LED33 to a paper discharge tray. Paper position display units 34W37 are located in positions situated facing the vicinity of a paper feed roller, a sensitized body, a fixing device, and a paper discharge roller, respectively. The display units usually display the number of copied papers by means of the LED30 and 31, but when jam occurs, the corresponding LEDs 34W37 are flickered depending upon their respective portions of a duplicator to indicate a paper stop position by means of the paper position display units 34W37. This facilitates maintenance of a duplicator.