Abstract: A machine is disclosed for printing and/or otherwise processing blanks of sheet material in which the interior of the machine is pressurized to a super-atmospheric pressure such that the blanks are forced firmly against the transfer conveyor between sections of the machine and dust in the ambient air is prevented from entering the machine and contaminating the print function.

Abstract: A paperboard processing machine is disclosed for printing and otherwise processing sheets of paperboard, such as corrugated container blanks, and in which the sheets are conveyed from one section of the machine to another section by one or more vacuum transfer systems. Each vacuum transfer system comprises an enclosure which is closed by a closure plate for creating a subatmospheric pressure, which pressure forces the sheets into frictional engagement with the reaches of a plurality of conveyor belts whereby the sheets are transported without contact of the opposite side of the sheet not contacted by the conveyor reach. In one embodiment the closure plate is imperforate, while in the second embodiment the closure plate is provided with a limited number of apertures for providing a secondary flow of air upwardly against the bottom surfaces of the paperboard sheets.

Abstract: A device is disclosed for receiving a disposable pipette tip, aspirating a supply of liquid into the pipette and dispensing the liquid in precise predetermined dosages. The device comprises a housing, a cylindrical passage within the housing, a piston extending into the passage from the rear end thereof and a plunger extending rearwardly from the piston. Actuating means are disposed within the housing for advancing the plunger forward in discrete amounts and a trigger extends from the housing operatively engaging the actuating means. The device further includes means for disengaging the actuating means whereby the plunger may freely be moved forward and back to permit a supply of liquid to be aspirated into the pipette. A detipping mechanism is also provided which permits a pipette tip to be removed without requiring any handling of it.