Marginal Markings
Prexy Era

by Lt Col John P McGowan
USAF Reserve, Retired

The Bureau of Engraving and Printing constantly experiments to improve stamp production. Two technological advancements are outstanding. Both have been equally important to this day. One has been the development which controls sheet alignment while perforation occurs.

The Post Office Department advocated a speedier stamp production which would justify an accurate method for perforation of stamps. About 34% waste was reduced to 1% due to implementation of this new technology.

Centering stamp sheets manually on a web carriage gave way to automated machine control during the prexy period of stamp production.

Marginal markings from pre-eye plates were short vertical or horizontal segments located on sheets at the extreme ends of gutters. The central intersection of the horizontal and vertical gutters was marked with a + sign in the sheet's center.

Technicians watched these markings in order to align the printed sheet with the perforator. This was done with toggle switches which manually moved the carriage forward, backward, left or right. This happened as the sheet was guided toward the first wheel and pin set for punching the horizontal line of holes.

After a horizontal line of holes was cut in the sheet's gutter by the 'L' model, a technician removed and turned the printed sheet 90 degrees. A second set of wheels and pins cut the vertical line of holes in the gutter.

The new electric eye principle did away with the older 'L' process. The Electric Eye process involved reflecting light beams onto newly designed marginal markings engraved on the EE plate. The purpose of these 'bars' and ÔdashesÕ was to automatically correct the web carriage by means of photo electric cells attached to the perforating machines so the line of holes corresponded to the center of the vertical and horizontal stamp gutters.

Revision Date: 11-19-2001