PURPOSE: To detect a paper at a low cost and with high accuracy by providing a paper guide surface with a paper position-regulating protrusion so that the surface of the protrusion extends along the common tangent to the peripheral faces of a feed roller and paper discharge roller.

CONSTITUTION: A paper printed by a printing part C is fed to a paper discharge roller 11 along a paper guide surface 9. In this case, the position of the printed paper is regulated by each pair of paper position-regulating ribs 31 so that no fluttering of the paper occurs and the paper can be prevented from coming into contact with the paper guide surface 9. Therefore, even if the paper is thin and ink permeates the rear face of the paper, the ink does not adhere to the paper guide surface 9 so that the paper can be prevented from becoming dirty. Thus, the paper can also be prevented by respective paper position- regulating ribs 31 from fluttering so that a reflection-type photosensor 21 with a small detection range and at a low cost can be arranged in close vicinity to the paper guide surface 9 and the sensor 21 can be used to detect the paper.