PRINTING MACHINE 655 



inking process, yet it exhibited for the first time the elastic inking-rollers, composed 

 of glue combined with treacle, which alone constitute one of the finest inventions of 

 modern typography. 



In the year 1815, Mr. Cowper turned his mind to the subject of printing machines, 

 and in co-operation with his partner, Mr. Applegath, carried them to an unlooked-for 

 degree of perfection. In 1816, Mr. Cowper obtained a patent for curving stereotype- 

 plates, for the purpose of fixing them on a cylinder. Several machines so mounted, 

 capable of printing 1,000 sheets per hour upon both sides, are at work at the present 

 day. (See figs. 1680 and 1681.) In these machines, Mr. Cowper places two paper- 

 cylinders sida 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 inking-rollers of about three inches in diameter 

 are placed ; they are kept in their position 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. 



1680 ^>* 1681 



Cowper's single, for curved stereotype. Cowper's double, for both sides of the sheet. 



The frame which supports the inking-rollers, called the waving-frame, is attached 

 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 to give them an 

 unceasing traverse movement. These rollers distribute the ink over three-fourths 

 of the surface of the cylinder, the other quarter being occupied 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 coloured 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 an impression upon its opposite side from the plates upon the second 

 cylinder. Thus the printing of the sheet is completed. 



In order to adapt this method of inking to a flat 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 extended cylindrical surface. Accordingly, Messrs. Cowper 

 and Applegath constructed a machine for printing both sides of the sheet 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 machine, 

 they dispensed with forty wheels, which existed in Mr. Konig's apparatus when Mr. 

 Bensley requested them to apply their improvements to it. 



The distinctive advantages of these machines, and which have not hitherto been 

 equalled, are the uniform distribution of the ink, the equality as well as delicacy with 

 which it is laid upon the types, the diminution in its expenditure, amounting to one 

 half upon a .given quantity of letter-press, and the facility with 1682 



which the whole mechanism is managed. The hand inking-roller 

 and distributing-table, now so common in every printing-office in 

 Europe and America, is the invention of Mr. Cowper, and was 

 specified in his patent. The vast superiority of the inking appa- 

 ratus in his machines over the balls used of old, induced him to 

 apply it forthwith to the common press, and most successfully. 

 See Jiff. 1682. 



To construct a printing machine which shall throw off two sides 

 <it a time with exact register, that is, with the second side placed 

 precisely upon the back of the first, is a very difficult problem, which 

 was practically solved by Messrs. Applegath and Cowper. It is - 



comparatively easy to make a machine which shall print the one table and roller, 

 side of a sheet of paper first, and then the other side, by the re- 

 moval of one form, and the introduction of another ; and thus far did Mr. Konig ad- 

 vance. A correct register requires the sheet, after it has received its first impression 



