PURPOSE: To set the head of a form to a prescribed position, by discriminating whether the signal of a sensor, which detects the mark on the running form, satisfied conditions of a software instruction or not to instruct a mechanical driver as prescribed.

CONSTITUTION: A form feed mechanism 1 consists of a stepping motor 11, a timing belt 12, and a sprocket 13. The rotation of the stepping motor 11 is transmitted to the sprocket 13 through the timing belt 12, and a form 5 is fed by the sprocket 13. When a mark 6 printed on the form 5 just under a sensor 3, the reflected light is converted to an electtic signal, which is not shown in figure, and is amplified and is sent to a controller 4. When the controller 4 discriminates that conditions are satisfied, the controller 4 instructs a mechanical driver 2 to stop the signal sent to the stepping motor 11 and stops the form feed. Thus, the controller 4 sets the head of the form to a TOF (top of form) position.