Types of Pressrooms and Presses

There are various kinds of pressrooms devoted to the process of printing from raised surfaces with the presses that have been developed for this purpose. Such pressrooms are found in job-printing plants, in book- and periodical-printing plants, and in newspaper-printing plants. Each of these places carries on a different type of work and each uses those presses which are best adapted to its special purpose. Platen presses are found only in job shops as a rule. Cylinder presses of various kinds are usually found in the pressrooms which do job and book printing, but they may also be used in the production of magazines. The cylinder presses are divided into the following classes: single-revolution presses or those in which the cylinder revolves once for each impression; double-revolution presses, in which the cylinder must revolve twice to make each impression; and flat-bed web presses which have a bed that remains stationary while the cylinder travels back and forth over it. This type also prints on a continuous roll or web of paper while the other two presses print on sheets of paper that have been cut to size. In recent years, there has also been developed a small cylinder press which operates at a high rate of speed. This machine is used in the pressrooms of job-printing shops. It is called the job-cylinder or baby-cylinder press. Rotary presses are found in book- and job-printing plants, in the pressrooms which print magazines and other periodicals, and in newspaper-printing plants. There are two types of rotary presses. One is the sheet fed press, which prints from flat sheets of paper. The rotary web-fed presses, which compose the other type, are divided into two distinct groups, one of which is used mainly in the printing of books and magazines, while the other is used for newspaper work.