Printing Auxiliary Equipment

Posted on 10-12-2013 by Admin

Auxiliary equipment for a sheetfed press is composed of those devices that perform specialized operational functions. These devices can significantly improve print quality and increase productivity. The following auxiliary equipment may be found on a sheetfed offset press:

. Remote control console, a free-standing computerized device that enables the press operator to control numerous press funcions without leaving the inspection table. A computerized (remote) console allows the operator to adjust inking, dampening, and circumferential register, control ink density and ink trapping; and monitor dot gain.

. Plate scanner, a device that measures the image area percentages at selected increments across the printing plate prior to mounting the plate on press. Most plate scanners, however, have been replaced by technology that allows automatic presetting of ink keys using the file data generated in prepress.

. Scanning densitometer, a computerized quality control table that measures and analyzes printed color bars using a densitometer.

. Sheet cleaners, which remove loose paper, lint, and dust from the surfaces and edges of the paper.

. Ink agitators, which keep ink in the fountain in constant motion, lowering its viscosity and allowing it to flow to the forward part of the fountain and transfer to the fountain roller.

. Water-cooled ink oscillators, which maintain the temperature of the ink oscillator at a level that will not set ink.

. Fountain solution recirculation systems, which pump fountain solution into each fountain pan from one or more central tanks.

. Fountain solution refrigeration unit systems, which keep the solution at constant, low temperature to avoid problems due to fluctuating dampening solution temperature; e.g., changes in viscosity. Chemical changes occur more slowly at lower temperatures.

. Fountain solution mixers, which mix fountain solution (dampening solution) in small quantities, constantly adding fresh fountain solution and maintaining greater uniformity. They are usually incorporated into recirculation systems.

. Automatic blanket washers, which remove ink and debris from the printing blanket. Various designs are used for blanket washers. One consists of a row of nozzles, mounted over the blanket, from which solvent is sprayed onto the rubber surface. Some automatic blanket washers also utilize a cloth and brush system.

. Automatic plate changers, devices that automatically mount a new printing plate on the plate cylinder.

. Antistatic devices, which turn the air immediately adjacent to the paper into a conductor by ionizing the air. Antistatic devices employ electricity, ultraviolet light, and even a weak radioactive field to neutralize static charges.