In 1814 two rotary presses were installed in the offices of the London “Times,” making it possible to turn out that newspaper at the marvelous rate of 11,000 impressions per hour. In this country, Richard Marsh Hoe invented a machine in which four, six, eight, or ten impression cylinders operated on a single form of type, thereby increasing the output of the press correspondingly. The first machine, a four-impression cylinder press, was used by the Philadelphia “Ledger” in 1846, and it printed 8,000 papers per hour.
Next came the “perfecting” press that printed on both sides of the paper, and then came the continuous web press, in which the paper was fed from a roll as a continuous sheet and, after receiving the type impression, was cut, folded, and delivered as a complete newspaper.
THE STEREOTYPE PLATE
Meanwhile stereotyping was introduced into newspaper printing. In stereotyping an impression in plastic material is made of the type face and then a casting is made from this impression which, of course, exactly duplicates the type face. The type is thus relieved from wear in the press and it is immediately released for use in setting up other copy while the printing is done from the stereotype plate. While the use of stereotyping in book printing dates back to the eighteenth century, it was not thought practicable for newspaper printing because of the length of time taken in making the plate, but in 1861 papier-maché was introduced as a matrix material and a system of rapidly drying the mold was developed so that a plate could be cast in a comparatively short time; furthermore, impressions could be made from a flat face of type and then the mold could be bent so as to make curved stereotype plates for use on the cylinder presses. In newspaper work it takes but five minutes to make a stereotype plate. Stereotype metal does not stand the wear of printing very long and the plates must be renewed from time to time. This fits in well with newspaper requirements because clean cut work is not called for, and as the news keeps coming in new editions must constantly be printed, which means that new plates must be made from time to time. For the finer printing of magazines and books, copper-faced electrotype plates are used in place of the soft stereotype plates of newspaper printing.
MODERN NEWSPAPER PRESSES
A modern large newspaper press is a bewildering sight to behold; there is such a vast number of rolls and cylinders, and the web of paper moves so rapidly. But, after all, the machine is multiplex rather than complex. It consists of a large number of printing cylinders, all operating in a single frame. Take, for instance, a double-octuple, color-combination press. It consists really of two separate presses, each operating on four webs of paper that feed from opposite ends toward the middle. There are two type cylinders for each web, one for each side of the paper. Each cylinder is long enough to take four stereotype plates side by side, and since each plate extends but half way around the cylinder we have eight pages printed on each side of the web. This makes sixteen pages per web or sixty-four for each half of the machine, giving a total of 128 page impressions at each turn of the cylinders. It is seldom that a 64-page paper is required, hence the webs are slit in two by a revolving knife blade and each section of the press has two folding mechanisms so that two sets of 16-page papers are printed, folded, and delivered by each section. Arrangements are provided whereby the product may consist of 32-page papers. The papers are delivered by a traveling conveyor and every fiftieth paper is pushed out ahead of the others so as to provide a simple method of keeping count of the product.
PRINTING 240,000 PAGES PER HOUR
The cylinders turn at the rate of 300 revolutions per minute which means that the paper runs through the machine at nearly 14 miles per hour. Summing up all the webs we have a total consumption of 108 miles of paper per hour. The paper is 6 feet wide and the weight of paper in an hour’s run is about 18 tons and the hourly production is 150,000 sixteen-page papers. When color is used, the press will deliver 50,000 24-page papers per hour with the two outside pages printed in three colors and black. The course of the color printed web must necessarily be different from that of the plain black printed web. It must pass through a number of printings; and to prevent the moist ink from transferring to the impression rolls and from them back to a succeeding page, thus soiling or blurring the impression, an extra roll of thin paper is passed between the printed web and the impression cylinders. This acts in a measure as a blotter. The offset paper is taken up on a roll and used over and over again. It is used not only for color work, but also when fine half tone engravings are to be printed so that a cleaner impression may be obtained.