| 摘要 |
PROBLEM TO BE SOLVED: To prevent the fall of a selected sheet material from a sheet material discharge tray. SOLUTION: Regarding an image forming device equipped with a sheet material size selector means 4 to select the size of a sheet material used for the formation of an image thereon, and a sheet material discharge tray to stack sheet materials discharged after the formation of an image thereon, and formed to be adjustable in length, a detection means 1 to detect the length of the sheet material discharge tray is provided, together with a judgment means 2 for making judgement as to whether the length detected with the detection means 1 is enough to stack sheet materials selected with the sheet material size selector means 4. |
