Design and Test of an Inking System Modification for Reducing Foreign Particle Accumulation on Lithographic Printing Plates.

A system for reducing hickey accumulation on the plate of a lithographic printing press is described. The principle employed is that of positively driving the first ink form roller at a surface speed substantially slower than the surface speed of the plate so as to produce a scrubbing action on the plate. A method for quantitatively measuring hickey removal rate was developed and used to evaluate the performance of the system on three different press designs. The three test presses also differed in that three different drive schemes were used to achieve roller slowdown gear drive from vibrator roller, gear drive from plate cylinder, and chain drive from the inker. In one of the test presses comparable data was obtained using two different commercial Hickey Rollers, and a limited evaluation was made of the influence of roller speed roller speedup vs slowdown and roller durometer. In addition the long-term performance of the system, obtained under field conditions in over forty press installations is summarized. the system, obtained under field conditions in over forty press installations is summarized.