Abstract: A printer includes a clam shell mechanism having a frame rotatably mounted on a base. A platen is mounted on the frame. A print head for acting in cooperation with the platen is mounted on the base. A locking lever mounted on the base cooperates with a shaft mounted on the first frame for selectively maintaining the first frame in a closed position. A lock control member switches the locking means between maintaining the first frame in the closed position and allowing the first frame to rotate to an open position wherein the platen is displaced from the print head.

Abstract: An end of paper roll detection assembly for detecting the end or near-end of a paper roll on a hollow core is provided. The end of paper roll detection assembly includes a detecting bar pivotally mounted on a retaining bar biased towards the side face of the paper roll which is supported on an adjustable paper roll retaining member. When paper is consumed the core is lowered towards the retaining member until the core is aligned with the detecting bar which passes into the hollow core thereby actuating a switch for generating a signal indicating that a predetermined amount of paper remains on the roll. The switch may be a reed switch closed by a permanent magnet secured to the retaining bar or a microswitch operated by the retaining bar. The retaining bar pivots towards the paper roll by action of a pulsating electro-magnet or a spring biasing the retaining bar towards the paper roll.