a paper feed mechanism includes a platen rotatably mounted on a frame and a friction feed having a support which rotatably supports a roller , the support being movable between an operable position in which the roller is in biasing engagement with the platen and a non - operable positon in which the roller is not biased toward said platen . a spring biasingly urges the support in its operable position in which the roller is in biasing engagement with the platen . a cam is rotatably mounted on the frame and rotatable between a first cam position which moves the support to its non - operable position and a second cam position which permits the support to be moved to its operable position by the spring , whereby the cam controls the operability of the friction feed .