ROTARY PRESS

Nelson Evening Mail, Volume LXXI, 24 April 1937, Page 1 (Supplement)

ROTARY PRESS

Process of Printing Astonishing Speed Remarkable progress has been triads in the evolution and improvement of rotary printing presses. Astonishing speed has been achieved. Such speed varies, of course, according to the size of the issue to be printed. The Hoe machine upon which “The Mail” is now printed, will produce 16r page issues at twice the speed it can attain in turning out a 32-page issue. Thus, the larger the issue the slower is the printing proportionately. Yet, even when uncommonly large papers are printed, the machines achieve a speed of production sufficient to command the wonder of the onlooker. A SIMPLE PRINCIPLE The principle underlying the operation of such processes is simple, though the execution of that principle and the detail involved may be highly intricate. In brief and rough outline, however, it may be said that the stereo plates (each representing a page of type) are clamped on to strong steel rollers (two plates on each roller), forming a complete cylinder of type. The printing surface of the plates comes intCTlfcoatact with-special rubber or composition rollers which impart ink, and, on the next half-revolution, come inlo contact, with the stream of paper running from a huge reel. Contact between the inked plate and the paper leaves the impression which forms the printed sheet. A brief description of the structural design of a rotary press may be both interesting and helpful towards a better understanding of its operation. The modern rotary press is built on what is known as the unit system. Thus the machine is divided into different units, each of which prints a different section of the paper.

A PLAIN EXAMPLE As an example, a press, printing a 16-page issue, may be considered. Such a press may consist of, say, four units. Each unit (in the case of a 16-page issue) would print four pages, and each would be served by a separate reel of paper. Thus, No. 1 unit of the machine (in a 16-page issue) would print pages 1,2, 15 and 16. No. 2 unit would print pages 3,4, 13 and 14. No. 3 unit would print pages 5,6, 11 and 12. And No. 4 unit would print pages 7, 8, 9 and 10. With each unit fed by a separate roll of paper, there would, ultimately, be four streams of paper coming from the whole machine. These four streams would be brought together until they lay one on top of another, forming one stream of four sheets. The one stream would then run Into the final part of the machine, the folder. In the Hoe press on which “The Mail’ ’is now printed, for a 16 page paper, two plates of each page are cast. Thus the paper is printed just twice as quickly as if one cast of each page were used. The machine will produce 24,000 copies of a 16 page paper per hoqr or 48,000 copies per hour o an 8 page paper.

TIIE FOLDER’S WORK The folder first folds 'the sheets, forming the crease down the middle. It then cuts through the stream at the end of every page, thus converting the endless stream into individual copies. And, finally, it folds the paper across the middle of the pages, turning them out in an endless flow. To complete its work, the machine automatically counts the copies and records their number on a small instrument much like the speedometer of a motor car.

The paper has at last been printed, and is ready for delivery to the readers. The delivery system, in itself highly organised—for fast and efficient transport services, as well as a largo number of runner-boys, must be enlisted in the distribution of many thousands of copies each day—closes the daily epic of the production of a newspaper.