<p>The printer includes an input structure for conveying the sheet of recording paper along an input path. A cylindrical platen roller rotatable about a longitudinal axis of rotation has a circumferential outer surface. A clamping mechanism is movably attached to the roller and is extendable between two radial positions. The mechanism has two members each extending radially from the longitudinal axis toward the circumferential surface. A clamper bar is disposed parallel to the longitudinal axis and is attached to the members. A bias member biases the clamping mechanism to the second radial position. The clamper bar is pressed against th circumferential surface. A control arm, is movable between a position where the clamping mechanism is engaged and mechanically moved to the first radial position and a second position, where the clamping mechanism is not engaged and the compare bar is in the second radial position.</p>
