7S7 



PRINTING. 



PRINTING. 



the sheet of paper between them, folded down on the form, the whole 

 is run, by turning the crank-handle, under the platen a, which is a 

 massive plate of cast-iron, moveable up and down perpendicularly, its 

 weight being rather more than counterbalanced by the weight I at the 

 back. The pulls the handle of the bar H towards him, or 



across the press, and thus communicates motion to It and /, and causes 

 the spindle m, which sustains the platen, to descend and produce the 

 requisite pressure. The principal improvement of the Stanhope press 

 consists in the manner in which the descending motion is given to the 

 screw. This depends on the properties of the bent lever, and may be 

 explained in the following manner : It is a necessary consequence oi 

 the peculiar combination and arrangement of the bent lever here 

 employed, that on the handle H being moved, the platen descends 

 rapidly at first ; but as the platen comes Very near to the extreme 

 point of its descent, the motion ifl extremely slow. But at this 

 instant the platen ia pressing the paper upon the types, and the 

 pressure exerted being inversely as the rate of the descent of the 

 platen, whose motion at this instant is exceedingly slow, the pressure 

 produced ia enormously large. It will be found also that at the 

 instant the platen is at its lowest point, the connecting bar /, by which 

 the power applied is transmitted to the platen, passes across the 

 centres of motion of the system of forces ; at this instant, as theory 

 points out, the ratio of the pressure produced to the power applied is 

 indefinitely large. The pull having been made, or the pressure pro- 

 duced, the handle u returns to its original position, being taken back 

 by the weight I at the back, which rather more than counterbalances 

 the platen. The carriage is then run back, the frisket and tympana 

 unfolded, and the printed sheet being taken out, the same operation is 

 repeated. The usual rate of printing by the Stanhope press ia two 

 hundred and fifty per hour, two men being employed, one to ink the 

 types, and the other aa pressman. 



The principle of the Stanhope press has been followed out by 

 several subsequent inventors, and improvements of mechanical detail 

 introduced, tending to the economy of tune and labour, and to pre- 

 cision of workmanship. In the Kuthven press, the form of types 

 remains stationary, and the plattin is removed to permit the types to be 

 inked ; and in this, as well as the Columbian, the pressure is produced 

 by a combination of levers alone, without the use of any portion of a 

 screw or inclined plane. 



The press for copper-plate printing consist* of two cylinders, or 

 rollers, of wood, supported in a strong wooden frame, and moveable 

 .it". ut their axes, one placed just above and another just below the 

 level of the table upon which the plate to be printed ia laid. The 

 upper roller ia turned round by the arms of a cross fixed to its axis. 

 The copper-plate being inked, the paper on which the impression is to 

 be taken, and two or three folds of aoft material, as blanketing, are 

 placed. upon it. The plate BO prepared ia moved along the table to 

 the juncture of the two rollers, and the upper roller being turned by 

 the arms of the cross, the plate, with Ha furniture, ia passed through 

 the press. The rollers may be placed nearer to or farther from each 

 other, according to the amount of pressure requisite for making a good 

 impression, that is, according to the depth of the engraving and the 

 degree of blackness which the impression is required to have. With 

 alight modification the same form ia used for lithographic printing, to 

 which steam-power has been recently applied very effectively. 



Machine. The printing-presa, though much improved 

 during the last half-century by the ingenuity of Lord Stanhope and 

 others, is quite inadequate to a rate of production equal to the present 

 demand. The attention of practical men waa consequently directed 

 to aome more rapid means of production, aud as early aa 1 790, even 

 before the Stanhope-press waa generally known, Mr. W. Nicholson had 

 letters-patent for a machine similar in many respects to those which 

 have now come into use. Subsequently Mr. Kb'nig, a German, con- 

 ceived nearly the same idea, and meeting with the encouragement in 

 this country which he failed to obtain on the Continent, constructed a 

 piinting-machine, and on the 28th of November, 1814, the reader.-* of 

 the ' Tiinea ' were informed that they were then for the first time 

 reading a newspaper printed by machinery driven by steam-power. 

 This printing-machine, though highly ingenious, was very complicated, 

 and the machine of Konig waa soon superseded by that of Messrs. 

 Applcgath and Cowper, the novel features of which were accuracy in 

 the register, the method of inking the types, and great simplicity in 

 hitherto very complicated parts. Printing-machines may be distin- 

 guished into single and double ; the single being that in which only 

 one side of the sheet of paper is printed, the double that in which both 

 sides are printed before the sheet leaves the machine. The former ia 

 used for newspapers and that kind of printing in which it is not neces- 

 sary for the two aidea of the sheet to " register," that is, for the print- 

 ing i >n one side to be exactly at the back of the other ; the latter for 

 books, in which it ia essential that the printing on one page should 

 correspond with the printing on the other when the sheets are folded. 

 Thia important object of the register is effected by causing the parts 

 to move at precisely the same speed. This being the principle of the 

 register, its success will depend on great accuracy of workmanship in the 

 _mecuanical parts. The accompanying representation of the printing- 

 machine will furnish a correct notion of the eeveral parts, and of the 

 way in which motion ia communicated to them. A sheet of paper is 

 taken from the pile to be printed (as represented at the left-hand side 



of the drawing), and put into the machine by one attendant, and taken 

 out printed on both sides by the other attendant, whose hand is 

 shown under the cylinders. The accompanying sketch will show the 

 principle of the printing-machine. 



The sheet of paper token from the table A is kid on the feeder B, 

 which consists of girths of linen, tightly stretched by being passed 

 round two cylinders. By the motion of this feeder the sheet is placed 

 between the two systems of tapes which lie on the cylinder o : these 

 tapes, of which one set is represented by the dotted line, and the other 

 by the thin line, lie two and two over each other on the cylinders and 

 small rollers a, b, c, d, e,f, y, It, i. The sheet of paper grasped between 

 them is kept clean at the places in which it is in contact with them, 

 and by the motion of the various parts is conducted under the first 

 priuting-cylinder H, and receives an impression from the types at ; 

 thence by means of the cylinders I, K, to the second printing-cylinder 

 L, where it receives an impression on the other side from the types at 

 D. Thus printed on both sides, it is taken out at c by the attendant. 

 The cylinders I and K are simply for the purpose of conveying the 

 sheet steadily and smoothly from one printing-cylinder to the other. 

 The sheet will be seen to be reversed in its progress from one set of 

 types to the other, descending the left side of the first and the right 

 side of the second printing-cylinder. 



An inking-apparatua is placed at each end of the table M, N, which 

 carries the types c, D, and which traverses backwards aud forwards 

 under the printing-cylinders L, H, and inking-rollers. The ink, received 

 from a reservoir It by the two rollers I and m, is transferred from them 

 to the surface of the table ; the surface of the table inks the rollers n, 

 u, and these, in their turn, ink the types as they pass backwards and 

 forwards for each impression. The excellence of the printing depends 

 in a great measure on the types being properly inked. In a machine 

 arranged according to the accompanying diagram, the types are touched 

 four times by the inking-rollera for each impression, and by increasing 

 the number of rollers, any perfection of inking may be obtained. The 

 machines commonly used for printing books will print from seven 

 hundred to one thousand per hour, in perfect register ; and for news- 

 papers printed on one side only, from four thousand to six thousand 

 per hour. 



Steam-power has also been applied to flat machines, which are a 

 modification of the Stanhope press, in which the table, with a form of 

 type at each end, moves backwards and forwards under the platen, 

 which gives the impression to one form while the other is being inked 

 by the rollers. This description of press was for a time supposed to 

 be best adapted for the finer sorts of book-work ; but the process was 

 very much slower, and the belief in their superiority of work was not 

 universally admitted. Cylindrical machines were frequently used, not 

 only for newspapers, where rapidity of production waa required, but 

 for books containing engravings on wood, where excellence of work- 

 manship waa demanded. Several of these machines were exhibited at the 

 Paris Universal Exhibition in 1855, the French printers having devoted 

 much attention to the improvement of cy lindrical machines. In his report 

 aa juryman on 'Class XXVI. Drawing and Modelling, Letter-press 

 and Copper-plate Printing, and Photography/ Mr. Charles Knight says, 

 " In the Paris Exhibition, several machines, offering the advantage of 

 more perfect inking, and of preventing what is called ' setting-oil" [that 

 is, the sheet becoming blurred by the moist ink being pressed upon], 

 showed that the attention of the French printers had been more 

 directed than with us to the practicability of producing the finest 

 work by the machine instead of by the hand-press. Some of our 

 artists, who have watched the dependence of the wood-engraver on the 

 printer, have long been of opinion that the equal operation of the 

 syUnder is superior to the irregular force of the hand-press. But the 

 beads of our printing establishments have generally considered that 

 the cylindrical machine was only calculated to save labour, and not to 

 produce fine work. Our machine-makers have, therefore, made various 

 ^hour-saving machines upon the principle of flat pressure, which, as it 

 ia the principle of the hand-press, at which the most expensive work 

 was produced, was thought to be the only principle for a more perfect 

 machine. The French, on the contrary, have turned their attention 

 to the perfection of the cylindrical machine, knowing that it had 

 natural advantages which could not be obtained by Hat pressure. 

 When a sheet of paper is brought into contact with an inked surface of 

 ;ypea, by being laid flat upon that surface, a large body of air has to be 

 expelled by the heavy platen, operating at once upon the whole sur- 

 face. The cylinder, on the contrary, touches the type, and produces 

 the impression on the paper, line by line, and there is no atmospheric 

 resistance to be overcome. The French printers have, therefore, 

 sought for the improvement of the cylindrical machine. The single- 

 cylinder machine of M. Dutartre produces work which cannot be 

 excelled by the most careful operations of the press. It prints only on 

 one side [the process having to be repeated to ' perfect ' the sheet] ; 

 and the form passes under a double set of inking-rollers, at each end of 

 ;he table, before it receives the impression. In the double-cylinder 

 machine of the same inventor, a waste sheet of paper is interposed so 

 as to prevent setting-off ; and thua both sides of the paper may be 

 Minted at once, without leaving that blurred impression of one side 

 which so commonly disfigures machine- printing. The French printers 

 now do their finest work by the cylindrical machine, and much of their 

 common work by the hand-press." The report goes on to say that, on 



