undersides of the corresponding flat beds 26 thus regardless of the rotational position of the turntable 24 vacuum pressure is maintained in each of the flat beds 26 thereby securing the materials 28 to be printed to their respective flat beds 26 during multiple printing operations as shown in fig4 and in cross section in fig6 and 7 the vacuum ring 32 is annular and preferably of u shaped cross section that is the inner sidewall 48 and outer sidewall 50 of the vacuum ring 32 together with the bottom wall 52 define the trough 54 the trough 54 allows vacuum pressure to be distributed simultaneously to each of the apertures 40 in the turntable 24 referring to fig4 the bottom surface 52 of the vacuum ring 32 contains a vacuum port 56 therethrough to which one end of a pump hose 47 is attached the vacuum port 56 is preferably located approximately midway between the inner sidewall 48 and outer sidewall 50 of the vacuum ring 32 the diameters of both the vacuum ring 32 and the vacuum port 56 will vary depending upon the particular design and operating characteristics selected however the vacuum ring 32 and vacuum port 56 should be of sufficient diameter to allow a flow of air ample to maintain vacuum pressure at the flat beds 26 suitable flanged fittings 47a connected the upper ends of the vacuum hose 47 to the underside of the annular ring as best seen in fig2 the annular.