SECTION III. TECHNICAL PRINCIPLES OF OPERATION
1-14. TECHNICAL PRINCIPLES OF OPERATION. The Printing Plant, Special Warfare, Transportable, is comprised of
two S-280 shelters. The Press Shelter contains limited capacity printing and paper cutting capabilities. The Editorial
Photomechanical Shelter contains typesetting, art work preparation, darkroom and plate making capabilities. For
expanded operation, the Modular Printing System (MPS) contains Modules B and C. Refer to TM 5-3610-303-12&P for
camera operating principles, and to TM 5-3610-302-12 for phototypesetter operating principles.
The printing process begins when an image is produced on a plate or master. The image is made of a substance
that has an affinity for grease-containing material and will tend to hold ink more strongly than the blank (non-imaged)
area of the plate. A moistening solution is manually applied to the surface of the plate. This application renders the
blank (non-imaged) area repellent to ink.
The plate is mounted on the master cylinder of the duplicator. The duplicator is turned on and the cylinders begin
to rotate in the directions shown by the arrows in Figure 1-5. The single-lever control is moved to the MOIST position.
This brings the moisture form roller into contact with the plate, and moisture in the form of fountain solution is applied to
the entire surface of the plate.
After four or five revolutions, the single-lever control is moved to the MASTER INK position. This action brings the
two ink form rollers into contact with the plate, and the image becomes inked while the blank area remains free of ink.
The ink adheres to the image and is not driven off by the moisture because the attractive tendency of the image remains
stronger than the repelling tendency of water. This condition is maintained as long as ink and moisture are applied in the
proper amounts, in which case they are said to be in balance. After ink has been applied for three or four revolutions, the
single-lever control is moved to the PRINT position. This brings the master cylinder into contact with the rubber blanket
on the blanket cylinder, with the result that a reversed (or mirror) image is offset onto the blanket. This image is allowed
to build up for a few revolutions of the cylinder before paper is fed.
The pump switch is turned on and the vacuum feet pick up the topmost sheet and feed it to the pullout wheels.
The pullout wheels feed the sheet onto the moving tapes of the register board. The tapes carry the sheet to the feed
rollers, which in turn feed the sheet to the grippers of the impression cylinder. A mechanism detects the sheet and
causes the impression cylinder to press the sheet against the blanket as the sheet passes through the nip formed by the
impression cylinder and the blanket cylinder. The reversed image on the blanket is impressed upon the sheet and
reversed again to become a correct reading image. When the leading edge of the sheet emerges from the nip of the
cylinders, the grippers open to release the sheet, and guides it into the receding stacker for jogging.
a. MPS Press Section (Module B). Module B is comprised of two Press Sections, each of which is a two-sided
expandable 8' x 8' x 20' tactical rigid wall ISO shelter. Each shelter is equipped with a two-color offset perfecting printing
press, environment controls, sink, lithographic layout cabinet, work tables and storage space for printing supplies.