In 1815 Mr. Cowper obtained a patent for curving stereotype plates for the purpose of fixing them on a cylinder. Several of these machines, capable of printing 1000 sheets per hour on both sides, are at work at the present day; and twelve machines on this principle were made for the Bank of England a short time previous to the issue of gold.
Donkin and Bacon's Machin for Typs.
Cowper's single, for curved Stereotype.
Cowper's double, for both sides of sheet.
It is curious to observe that the same object seems to have occupied the attention of Nicholson, Donkin and Bacon, and Mr. Cowper, viz. the revolution of the form of types. Nicholson sought to do this by a new kind of type, shaped like the stones of an arch. Donkin and Bacon sought to do this by fixing types on a revolving prism; and at last it was completely effected by the curving of a stereotype plate by Mr. Cowper.
In these machines two paper cylinders are placed side by side, and against each of them is placed a cylinder for holding the plates; each of these four cylinders is about two feet diameter; on the surface of the plate cylinder are placed four or five inking-rollers, about three inches diameter; they are kept in their position by a frame at each end of the plate cylinder, the spindles of the rollers lying in the notches on the frame, thus allowing perfect freedom of motion, and requiring no adjustment. The frame which supports the inking-rollers, called the waving-frame, is attached by hinges to the general frame of the machine; and the edge of the plate cylinder is indented, and rubs against the waving-frame, causing it to wave or vibrate to and fro, and, consequently, to carry the inking-rollers with it, thus giving them a motion in the direction of their length, called the end motion. These rollers distribute the ink upon three-fourths of the surface of the plate cylinder, the other quarter being occupied by the curved stereotype plates.
The ink is held in a trough; it stands parallel to the plate cylinder, and is formed by a metal roller revolving against the edge of a plate of iron; in its revolution it becomes covered with a thin film of ink; this is conveyed to the plate cylinder by an inking-voller vibrating between both. On the plate cylinder the ink becomes distributed, as before described, and as the plates pass under the inking-rollers they become charged with colour: as the cylinder continues to revolve, the plates come in contact with a sheet of paper in the first paper cylinder, whence it is carried, by means of tapes, to the second paper cylinder, where it receives an impression on its opposite side from the plates on the second plate cylinder, and thus the sheet is perfected. These machines are only applicable to stereotype plates, but they formed the foundation of the future success of Applegath and Cowper's printing machinery, by showing the best method of furnishing, distributing, and applying the ink.
In order to apply this method to a machine capable of printing from type, it was only necessary to do the same thing in an extended flat surface or table, which had been done on an extended cylindrical surface; accordingly Mr. Cowper constructed a machine for printing both sides of the sheet from type, securing by patent the inking apparatus, and the mode of conveying the sheet from one paper cylinder to the other by means of drums and tapes.
Applegath and Cowper's Single Machine.
Appleyath and Cowper's Double Machine.
Mr. A. Applegath, who was a joint proprietor with Mr. Cowper in these patents, obtained patents for several improvements. Mr. Cowper had given the end motion to the distributing rollers by moving the frame to and fro in which they were placed. Mr. Applegath suggested the placing of these rollers in a diagonal position across the table, thereby producing their end motion in a simpler manner, - a plan of which we subjoin. A is the inking table or flat surface, on which the ink is spread and distributed; B is the form of types; C C C are the rollers for communicating the ink to the types; D D D are the distributing rollers placed diagonally across the table, their pivots resting in slots in the carriages. The table is made to slide backward and forward, causing by that motion the rollers to revolve, which are nicely adjusted in contact with the table, so as to press evenly on the surface of it, those in the oblique position causing the ink upon the surface to be spread out very evenly, so that the rollers C C C, which follow in action, become charged very uniformly, and deliver it to the type in like manner.
The diagonal rollers must have an admirable tendency to spread out the ink in a smooth stratum, by the sliding of the table in a different direction to the lines of revolution; but there must be considerable friction at their axes by the constant tendency of the table to thrust the rollers sideways or endways, which must be provided against, or they will soon wear untrue. He also contrived a method of applying two feeders to the same printing cylinder; these latter inventions are more adapted to newspaper than to book-printing. Numerous machines have been constructed upon the joint inventions of Messrs. Applegath and Cowper, which are modified in a great number of ways for the various purposes of printing books, bank-notes, newspapers, etc.; they have, in fact, superseded Mr. Koenig's machines in the office of Mr. Bensley (who was the principal proprietor of Koenig's patent), and also in the office of the Times, as was announced in that journal. No less than forty wheels were removed from Koenig's machines when Mr. Bensley adopted the improvements of Messrs. Cowper and Applegath. Having, on the first trial of their machines, discovered the superiority of the inking-roller and table over the common balls, they immediately applied them to the common press, and with complete success; the invention, however, was immediately infringed throughout the kingdom, and copied in France, Germany, and America; and it would have been as fruitless to have attempted to stop the infringement of the patent as it was found in the case of the kaleidoscope.