Nicholson sought to effect the revolu tion of the form of types by giving to the shank of a type a shape like the stone of an arch ; Donkin and Bacon by attach ing types to the sides of a revolving prism ; and Cowper, more successfully, by curving a stereotype plate. In these machines Mr. Cowper places two paper cylinders side by side, and against each of them a cylinder for holding the plates ; each of these four cylinders is about two feet in diameter. Upon the surface of the stereotype plate cylinder; four or five ink ing rollers of about three inches in diame ter are placed; they are kept in their po sition by a frame at each end of the said cylinder, and the axles of the rollers rest in vertical slots of the frame, whereby; having perfect freedom of motion, they act by their gravity alone, and require no adjustment.
The frame which supports the inking rollers, called the waving-frame, is attach ed by hinges to the general framework of the machine; the edge of the stereotype plate cylinder is indented, and. rubs against the waving-frame, causing it to vibrate to and fro, and consequently to carry the inking rollers- with it, so as give them an unceasing traverse move ment. These rollers distribute the ink over three-fourths of the surface of the cylinder, the other quarter being ocenpied by the curved stereotype plates. The ink is contained in a trough, which stands parallel to the said cylinder, and is formed by a metal roller revolving against the edge of a plate of iron ; in its revolution it gets covered with a thin film of ink, which is conveyed to the plate cylinder by a distributing roller vibrating between both. The ink is diffused upon the plate cylinder as before described ; the plates in passing under the inking rollers become charged with the colored varnish •, and as the cylinder continues to revolve, the plates come into contact with a sheet of paper on the first paper cylinder, which is then carried by means of tapes to the second paper cylinder, where it receives the impression upon its opposite side from the plates upon the second cylin der.
Thus the printing of the sheet is com pleted. Though the above machine be applicable only to stereotype plates, it has been of general importance, because it formed the foundation of the future success of Messrs. Cowper and Apple gath's printing machinery, by showing them the best method of serving out, distributing, and applying the colored varnish to the types.
In order to adopt this method of ink ing to a fiat type-form machine, it was merely requisite to do the same thing upon an extended flat surface or table, which had been performed upon an ex tended cylindrical surface. Accordingly, Messrs. Cowper and Applegath con structed a machine for printing both sides of the sheets from type, including the inking apparatus, and the mode of conveying the sheet from the one paper cylinder to the other, by means of drums and tapes. It is highly creditable to the scientific judgment of these patentees, that in new modelling the printing ma chine they dispensed with forty wheels, which existed in Mr. Klinig's apparatus, when Mr. Bensley requested them to ap ply their improvements to it.
In England, Treadwell's power-press has been, until lately, very much em ployed. In this invention the types are inked by elastic rollers, and the dis tribution of the ink rendered equal by a revolving table, which keeps in contact with the rollers. The impressions are made by a flat surface, or platen, instead of a cylinder, so that cleaner and better impressions are supposed to be obtained from it, than by any other machine. Kiinig's machine continued in use by the Times newspaper (England) till 1827, when it was superseded by Applegath & Cowper's four-cylinder machine, produ ci?g 5000 per hour. Sonic of them are still used in that office. They consist of a table moving to and fro under four iron cylinders, about nine inches diameter, covered with cloth, and round which the paper is carried. The form is fixed at one part of the table, and the ink and paper at another. Some of the rollers were laid diagonally, so that as the table moved, the rollers had a motion in the direction of their length; this movement aided the rotatory one in better inking ; the ink lay in in a trough in an iron roller or darter, exactly similar to that used in Calico printing (which see). Four layers on fed the rollers, which by tapes carried the sheets to the takers-out at the other end. In May, 1848, the last improve
ment was made by the adoption of a new machine, which threw off the large quantity of 10,000 copies per hour. This machine was a vertical cylinder, 65 inches broad, on which the type was fixed, sur rounded by eight other cylinders, each about 13 niches diameter, and covered with cloth, round which the paper was led by tapes, each paper cylinder having a feeding apparatus and two boys tend ing. The ink rollers were also vertical against the large cylinder, and on which they distributed the ink. This last was in a vertical cylinder. The type used is the ordinary kind, and the form is placed on a portion of the large cylinder. The surface of the type formed a portion of a polygon, and the regularity of the im pression was obtained by pasting slips of paper on the cylinders. On the 7th May, 1850, the Times newspaper and Supple ment contained 72 columns or 17,500 lines made lip of more than a million pieces of type; of this copy, the last form went to press at 4 45 A. M. 7000 copies were pub lished before 6 A. D.,17,000 before 7 80A. M., and 34,000 before 8 45 A. M., or in about four hours. On March 9th, 1850, an exhibition of a new rotary press took place in Paris, which was worked by cylin drical motion, and by a stereotype obtain ed from several sheets made of a pulp of paper, which gives more depth than is usually obtained from plaster of Paris, and the printing is so that even maps are produced from their cylindri cal stereotypes with the minutest accuracy. It is the invention of Worms, once a Par risian printer. The stereotype cylinder was got up in 15 minutes and the print ing on both sides was most perfect. It knocked off 15,000 copies by the hour ; this may bo augmented by steam power. The rapidity is owing to the printing on endless paper not wetted on rollers, each copy being cut up with great precision. This French rotary press has been ex celled by the mammoth the largest ever constructed. It was designed and built by Messrs. Hoe & Co., New-York : it is forty feet in length and five wide ; it has a large central drum which revolves like a broad wheel. The form (or there may be a number of them) is placed on the periphery of the central drum, but only occupies a portion of it. The chase is curved and forms the section of a cir cle, with the surface of the type forming the outside of the same. The type are secured in the curved chase in a pecu liar manner. The column-rules are straight and run parallel with the shaft of the large drum ; the head and dash rnles are curved. The column-rules have bottom flanges ; they slide in the grooves in the bed of the chase, and are secured by brass dove-tail wedges. The cross section of a column-rule is of a wedge shape, being thinner at the bottom than at the top, to wedge in the type at the wid est part of a circle which they form with the large drum. This is an essential fea ture in securing the type, and its appli cation is certainly the result of a very happy thought. The type is firmly screwed up in the chase by set screws. The surthce of the large drum of the press is composed of smooth metal plates, and performs the office of an ink distributor to the small rollers which ink the type. Below the large rotary drum, there is a trough running across the frame, into which the ink is pumped from a reservoir by a forcepump, so as to keep the trough always full. Above the ink trough there revolves a large roller, which takes up the ink on its surface, conveys it to another roller, that one to a third, and it to the smooth surface of the revolving drum, distributing the ink on it. The use of the three rollers to convey the ink from the trough, is to work and spread it on the distributing surface. As the type in the chase stands higher than the smooth surface of the rotary drum, the ink-roller below would cover the type with ink when it came round to it, were it not for a contiivanee of Messrs. Hoe to obviate this difficulty. The large ink-roller below has its gudgeons worked on springs, which press it up against the smooth surface of the large drum, except at the exact time during the passage of the type : then a cam forces down the ink roller below the surface of the type, until the form is past the point of contact, when it rises up against the distribution surface with its supply of ink.