On Demand Printing of Small Books by Conventional Offset Lithography: An Experimental Study
For on demand printing digital print is no doubt popular because this process able to print one or more copies as and when necessary, not only that any changes may be made if necessary. Conventional offset lithography printing process has not these facilities, but by re-using the same plate on demand printing may possible by this process with some limitations. Considering these, Four big size short run conventional pre-sensitized plates of plain text (with some border lines leaders etc.) matters of a small book (A3 size, 64 pages) were prepared by tracing positive generated from a 1200 dpi laser printer. Each of these four plates were used five times with some chemical treatments in the span of 3 years for printing by black ink on white matt finish coated paper by a single colour sheet-fed offset printing machines using plain water in the conventional dampening systems. Each time number of impressions was 500 sheets and samples from the printed sheets selected randomly. Subjective and objective measurements of print quality of the samples done by evaluating the maximum and minimum type density, number of broken types, appearance of scum on the sheets. By analyzing the positive results obtained from this experimental study and considering some other parameters this paper investigates about the possibilities of on demand printing of small books by conventional offset lithographic printing process using pre-sensitized plates. This paper also investigates the advantages and disadvantages, cost effectiveness of the process and reduction level of pollutants.
Keywords: On demand printing, Digital print, Conventional offset lithography, Pre-sensitized plates, Small book, Experimental study
Engineering Assistant, Publication and Printing Unit, Indian Statistical Institute