Abstract

Lithography is the most common printing process. However, very little is known about the theory of lithography. Pressroom practices have evolved more out of experience than on the basis of any theory. The objective of this paper is to develop a mathematical model for the non-image area of the offset lithographic plate. A model of this kind would provide a rationalization for the observed behavior in lithographic process. The study concentrates on the various materials and the phenomena involved. Properties of aluminum oxide surface and gum arabic that make them suitable for the process have been presented. Rheological properties of ink have been discussed to show their effect on the print quality. Most importantly the subject of surface energetics has been used to explain the interfacial behavior of the three phases involved - ink, fountain solution and plate surface. The study of the interfacial behavior helps in arriving at the final model. There are several phenomena taking place in making lithography work. Adsorption of gum arabic, wetting of the plate by fountain solution and film splitting at the nip exit are explained and the interrelationship between them derived. Surface energetic equations and Griffith's free energy for fracture have been used to present the final model for the system. The model as proposed in this paper gives a deeper insight into the lithographic process and helps- in understanding the reasons for the printing aberrations. There is a need to model other aspects of the process and design methods to test them so as to help in development of better equipment and standard practices for lithography.

Library of Congress Subject Headings

Offset lithography--Analysis--Mathematical models; Surface chemistry

Publication Date

2-1-1988

Document Type

Thesis

Department, Program, or Center

School of Print Media (CIAS)

Advisor

Silver, Julius

Advisor/Committee Member

Noga, Joseph

Advisor/Committee Member

Southworth, Miles

Comments

Note: imported from RIT’s Digital Media Library running on DSpace to RIT Scholar Works. Physical copy available through RIT's The Wallace Library at: Z252.5.O5 C397 1988

Campus

RIT – Main Campus

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