An automatic screen printing press has a platen turntable carrying a plurality of platens which are indexed through a plurality of stations in an endless path of movement past printing heads having a power-driven squeegee carriage thereon. The turntable is driven by a powered carriage having a linear guide that causes the carriage to have a linear reciprocal movement. Each of the printing stations has a roller cam that is selectively engaged by a shifting fork that is mounted for movement with the carriage. The shifting fork is driven in a transverse reciprocal direction to the linear reciprocal movement of the carriage for selective engagement with and disengagement from a roller cam.