(57) A pneumatic axially oscillated, frictionally rotated roller (30) is disclosed and
may be used in the ink (12) or dampening (13) systems of a printing press. The roller
(30) features an internal air piston-cylinder construction that causes the axial motion
but permits the roller (30) to freely rotate. Further, several air cylinders can be
stacked on each side of the roller (30) to permit even a small diameter roller to
be pneumatically oscillated. The roller (30), when used as an ink form roller (18),
may be operated to oscillate in synchronization with an adjacent oscillating, vibrating
roller (120) to continually diagonally redistribute the ink so as to eliminate or
minimize "ghosting". The foregoing is accomplished by controlling the oscillation
of the form roller (18) to move axially in a direction opposite of that of the vibrating
roller (120). The lengths of the strokes of the two rollers (30, 120) may differ or
be the same. The length of axial movement or stroke of the form roller (18) can be
varied, while maintaining synchronization by varying the speed of the axial motion,
a slower speed yielding a shorter stroke and a higher speed yielding a longer stroke
for a given half cycle.
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