Abstract: A holder for the frame of a printing screen is connected to an adjustment plate which, in turn, is mounted on a support arm assembly. The support arm assembly swings the holder up and down, toward and away from a printing platen. The adjustment plate has elongated slots for receiving eccentric lugs of manually rotatable cam members. The adjustment plate is normally fixed to the screen holder by a locking mechanism, but the locking mechanism is releasable so that the cam members can be rotated to effect a desired adjustment of the plate and the associated holder to achieve a desired registration of the printing screen relative to the printing platen. The support arm assembly also is adjustable to change the angle of the screen relative to the platen when the screen is lowered.