Page:EB1911 - Volume 22.djvu/371

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357
PRINTING

and passing through the cylinders to the folder at the other end where the copies are delivered. Three- and four-reel machines have also been constructed on the same principle, but the more usual arrangement of the four-reel press is to place two reels at either end, with the folders and delivery boards in the centre. This makes it possible to operate them as independent machines, or to run in combination with each other.

When presses are made in double width a two-reel machine is known as a quadruple, a three-reel as a sextuple, and a four-reel as an octuple machine. Double sextuple and double octuple machines are made, having six and eight reels respectively. The quadruple machine is a favourite one and is perhaps most in demand for newspaper work. This press prints from two reels of the double width. The first reel is placed to the right of the machine near the floor, and the second at the back of the machine and at right angles to it. A quadruple machine will produce 48,000 copies per hour of four, six or eight pages; and proportionately less of a greater number of pages; all folded, counted and pasted if required. The four cylinders, which are on the right-hand side of the press, are respectively the printing and impression cylinders—the two inside ones being those giving the impression, and the two outer ones bearing the printing surfaces. The inking arrangements are placed at the two extreme ends of these four drums or cylinders, thus being near the type surfaces in each case. As the paper is unwound from the reel below it travels between the first two cylinders when it is printed on the first side; it then passes to the third and fourth cylinders, which give it the second backing side, thus “perfecting” the printed sheet. From this point the long sheet is carried overhead to the left-hand side of the machine, where it is cut longitudinally and divided, and then associated with the other web similarly printed by the other half of the press. They then descend into the two different folders, where they are folded and cut—the copies being discharged on to the delivery boards situated at the two sides of the left-hand portion of the machine, and each quire is counted or told off by being jogged forward. This description applies to one half of the machine only, for while this is in operation the same thing is being repeated by the other half situated at the back.

Another machine, somewhat complex but quite complete in itself, is that constructed by Messrs Robert Hoe & Co. in London from drawings and patterns sent over from New York, for weekly papers of large circulation. Double sets of plates are placed on the main machine, which is capable of taking twenty-four pages, but by using narrower rolls the number of pages may be reduced to either sixteen or twenty if a smaller paper is desired. In addition to the body of the paper it prints a cover, and is capable of producing 24,000 complete copies per hour, folded, insetted, cut, pasted and covered. That portion of the machine which prints the cover is fed from a narrower reel of a different colour of paper from that used for the inside pages. The printing surface for one side of the cover is placed at one end of the cylinder and the reverse side is placed at the other end. This ingenious combination results in the printing of one cover for every copy of the paper.

EB1911 Printing - Hoe's Double Octuple Rotary Machine.jpg

Fig. 9.—Hoe's Double Octuple Rotary Machine.

The double octuple machines (fig. 9) erected by the same firm for the printing of Lloyd's Weekly News were probably, in 1908, the latest development in rotary printing. These presses print from eight different reels of the double width, four placed at each end of the machine, the delivery being in the centre, and from eight sets of plates, four pages on each type cylinder, making a total of thirty-two pages in all. Each press produces of that number of pages 50,000 Octuple Rotary Machines. copies per hour, printed both sides, cut, folded and counted off in quires complete; by increasing the sets of stereotype pages the same machine will produce 100,000 copies per hour of sixteen pages, and by duplicating the folding and delivery apparatus, 200,000 copies of eight pages of the same size. This mammoth press measures 54 ft. in length, 19 ft. in height and 12 ft. across; its dead weight is about 110 tons, and roughly 100,000 different pieces of metal were used in its construction. The rough cost of such a machine is probably about £18,000. Such a press requires two 55 h.p. motors, one at each end, to drive it. The press is practically four quadruple machines built together, each of which can be worked independently of the other. The paper is fed from reels placed at the two ends in decks, one above the other, each reel containing about five miles of paper, and weighing about fourteen hundredweight. The process of unwinding these long reels of paper in the course of printing takes only half an hour; they are arranged on a revolving stand so that directly they are spent the stand is turned half way round, and four other full reels already in position are presented ready to be run into the press. This ingenious arrangement, whereby the reels can be changed in about three minutes, obviates the loss of time previously incurred by the press being kept standing while the empty spindles were removed and replaced with four full reels.

Having described some representative types of the different classes of printing-presses in use, we may now treat of the The Preparation or Making-ready for Printing. methods employed by the workmen in securing the best results in printing. The real art of printing, as far as press work is concerned, lies in the careful preparation of the printing surface for printing before running off any number of impressions. This preparation is technically called “making-ready,” and is an operation requiring much time and care, especially in the case of illustrated work, where artistic appreciation and skill on the part of the workman is of great assistance in obtaining satisfactory and delicate results. Theoretically, if both type and press were new, little or no preparation should be necessary, but practical experience proves that this need of preparation has not yet been entirely obviated and still remains an important factor. Single proofs of type, stereotype, electrotype or blocks of any description can often be struck off without making-ready with fairly good results, but if precision of “colour” (that is, inking) and uniformity of impression throughout a volume are desired, it is necessary to put the forme, whether type or blocks or both, into a proper condition before starting the printing of an edition, whatever its number. And this applies to all good work produced from whatever presses or machines other than those built on the rotary principle. In these, even if time permitted, little can be done in the way of making-ready; nor