Abstract

A paper feed mechanism for use in a printer has a pin tractor unit disposed on one side of a platen which is opposite to a print head, and a paper guide plate located below the pin tractor unit. The pin tractor unit has an endless tractor belt trained around a plurality of pulleys to form a first guide passage above the pin tractor unit and a second guide passage inclined from the first guide downwardly toward a position beneath the platen. The tractor belt has pins for fitting into perforations defined in the side margins of continuous paper. The continuous paper is inserted between the pin tractor unit and the paper guide plate, threaded between the platen and the print head, and then extended along the first guide passage. By moving the tractor belt in a prescribed direction, the continuous paper can be pulled by the pin tractor unit so as to be fed along in one direction. Alternatively, the continuous paper is guided along the first and second guide passages or the second guide passage only, and then the tractor belt is moved in a direction opposite to the above prescribed direction to advance the leading end of the paper between the platen and the paper guide plate and then between the platen and the print head. The continuous paper can now be pushed by the pin tractor unit so as to be fed along in an opposite direction.