Presensitized
Printing plate 5 By Mr. Bob Gumbinner
Through
one of Freda or Gregory Halpern’s brothers, who was in the pocket
book business, we met Ed Harraz, who owned a company Century
Engineering on Orono St., in Clifton, NJ, that made machines to brush
the glass to be silvered for mirrors. He built for us a small one
brush rotating and reciprocating machine. We installed this in the
space in the Warburton-Ashburton building and experimented with using
slurry brush graining instead of chemical etching for the
presensitized plates. As soon as the 12,000 sq. ft. building on the
2 Ashburton lot was finished in 1959, Century Engineering built and
installed the A-line. This consisted of an endless belt on which the
sheets of aluminum were carried under four rotating and oscillating
brushes with hold-down rollers. A 30% slurry of fine pumice and sand
was sprayed on the plates before the brushes. The plates were
transported on chain driven rollers through a series of sections were
they were rinsed; then sprayed with either hot sodium silicate or
hot potassium zirconium fluoride solutions; rinsed dried and the
diazo coating was applied. At the same time we installed a second
tank line for making the chemically etched plates. We had occasional
complaints about the plates picking up ink in the non-image area. I
traced this to the use of chromic acid in the desmut solution. I did
not want to use 50% nitric which 3M was using. After working with
Ibert Mellan and another chemist, Gene Golda, who we had hired, I
found that sodium persulfate effectively removed the smut that formed
as the result of the sodium phosphate etching. The quality control
technicians would wipe the plate with a piece of cotton to make sure
all the smut was removed. We could control this by slightly
increasing the temperature of the persulfate bath. Also some people
were allergic to Chromium compounds. Larry Golusinski, the son our
plant manager, Leo, who was working on the second tank line developed
a rash, and was transferred to the sales department.