Abstract: A vacuum drum is located in close proximity to the lowermost flat workpiece in a stack of workpieces in a hopper for applying a suction to remove the bottommost workpieces one at a time from the hopper for passing on to a conveyor to a printing press. The drum is mounted on a reciprocably rotatable hollow-cored shaft for reciprocable rotation therewith and has multiple sets of vacuum outlets which can be selectively positioned in vacuum communication with the hollow bore of the shaft for feeding vacuum from the shaft bore to a selected one of the multiple sets of vacuum outlets so that the drum can be used for a variety of workpieces.

Abstract: A tray contains frothed or bubbly solution for applying to a printing cylinder plate and a cylindrical pan roller having a microporous outer layer is continuously rotated in the frothed solution to continuously absorb or pick up small amounts of the solution. Solution is transferred from the pan roller to a metering roller, having a surface of highly polished chrome, by rolling contact between the two rollers. In turn, the metering roller transfers liquid to a form roller which has a microporous outer surface in rolling contact with a printing plate mounted on the printing press printing cylinder for depositing the liquid solution onto the printing plate as the printing cylinder rotates. The pan roller and the form roller have hollow cores and pressurized air at a very low pressure is applied to the cores to uniformly spread the liquid throughout the microporous surface for uniform distribution.

Abstract: A device for feeding envelopes or similar work pieces to a printing press or the like utilizes a vacuum chamber mounted on a reciprocably driven roller for removing the lowermost envelope out of a stack of envelopes in a hopper and advancing it to a carrier for conveyance to the printing press. The vacuum is fed to the vacuum drum through an elongated passageway along the axis of the roller and a valve at the input of the vacuum at one end of the roller reciprocates with the roller to open and close the vacuum passageway. Also, a pusher lug is provided to assist in removing heavier stock from the hopper.

Abstract: A perfector printing press having a full size impression cylinder with a blanket thereon between the perfector roll and the plate roll so that printing is not done on the smaller radius perfector roller. The perfector is easier to reach for cleaning and changing and the quality of the printing is improved. The perfector may be spring loaded to prevent jam ups and pivoted about the impression cylinder for easier access.

Abstract: A two color printing press in which the plate cylinder for the second color and the ink supply rollers therefor are mounted in a pivoting frame which can be manually rotated away from the printing press to afford easy access to the interior of the press. Gear position indicators permit prealignment of the second color plate cylinder and rollers when they are swung into position.

Abstract: A device is provided for moistening the plate cylinders of offset printing machines. The device includes an inner rotatable sleeve having an air passage extending therethrough. Angularly extending passages are provided in the inner sleeve. The inner sleeve is rotatable within an outer fixed cylinder having spaced apertures all directed in the same direction. A film of water flows over the fixed cylinder. As the inner sleeve rotates air is forced through the inclined passage to force the water against a focus upon a diffuser which breaks the water up into a fine spray which is deposited upon the surface of a water cylinder so that the water is deposited from end to end thereof so that the plate is provided with a film of water throughout its length.