This paper studies the movement of material which accumulates on the image printing blanket of a web offset press printing newsprint. A theory is advanced to explain this movement. It is based on the differences in velocities of the paper and blanket surfaces entering and exiting the printing nip. The designed experiment run uses three factors to test the changes in direction and rate of movement. These are: (1) the compressibility of blanket sets, (2) the relative image printing and impression blanket diameters, and (3) the printing squeeze. No other factors involved in the nip area are tested. The movement of material on the blanket surface is recorded using stroboscopic photography on 35mm transparency film. The photographs record the positions of material on the blanket every 150 impressions. Analysis of the recorded movement is made by projection of the successive images. Results of statistical tests indicate that the relative diameters of the image printing and impression cylinders can influence the direction of movement. Movement is forward when the image printing blanket is less than the impression blanket and backwards when the image printing blanket is greater than the impression blanket. When printing with unequal diameters, the compressible blanket set produces less movement than the non-compressible set. These results support the theory advanced.
Library of Congress Subject Headings
Department, Program, or Center
School of Photographic Arts and Sciences (CIAS)
Stewart, Leigh, "A Photographic Study of Movement of Material On a Web Offset Press Blanket" (1973). Thesis. Rochester Institute of Technology. Accessed from
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