PRINTING PR ESS i; 5, 



PLATE 

 CCCCLXVII. 

 Fig. 12. 



Mr. Lir- 

 ars's cast- 

 iron press 

 Fig. 13. 



roller, a little larger in the <li;mu-ter than the upper ; 

 C the plank upon whieh the copperplate 1' i 



lioulil In- placed iipun a piece of pasteboard ofa lit- 

 tle lo:i- t -r -i/.r than the paper upon which tin- in.pn- 

 l,i l)c taken, in order to defend the plank against 

 the indentation eon-cquent on the necenhary pi> 

 oi' tlie roller. 1) U the stronge.st part oi'the J'r.nne of tli'J 

 press, commonly called the cheek >; d an open spa9e in 

 the cheeks for admitting tlu: axe- or spindles of the 

 rollers. The upper roller lias a brass bush fitted to 

 the upper hall' oi'the spindle, and upon which is placed 

 n proper quantity of pieces of pasteboard and felting 

 in alternate layers, in order to give elasticity to the 

 pressure, and greater ease to the workman. The spin- 

 dle of the under roller is also placed in a brass bush, 

 sometimes with, but oftener without, a mass of elastic 

 substance. In thi.s opening two screws are fixed, so 

 as to act upon the elastic mass placed above the spin- 

 dle* oi'the upper roller, for the purpose of regulating 

 the .pressure necessary to produce the requisite bold- 

 ness of the impression. Some skill is required in the 

 management of these screws, for we have seen that 

 strength of body, without this knowledge, has actually 

 broken the spindles of the rollers in vain attempts to 

 perform what a judicious workman would accomplish 

 with comparative ease. In order to keep the elastic 

 mass above described as efficient as possible, it should 

 be taken out at night, turned, and replaced in the 

 morning. Much of the excellence of the work also 

 depends upon the proper quantity of felting or cloth 

 being warped round the upper roller b b. If too 

 many layers are put on it, the result will be, that 

 greater power will be required to drive the press, and 

 the impression will not be so clear and distinct as it 

 ought; and again, if too few layers of cloth are 

 applied, the paper will be stained by the hardness 

 of the roller, and it will have a glazed appearance, 

 and be liable to be cut by the edges of the copper- 

 plate. These defects also result (though in a less de- 

 gree) from the want of a proper quantity of the elastic 

 mass being placed above the spindle of the upper 

 roller. K is the remaining part of the frame of the press, 

 and F the levers or cross fixed to the end of the spindle, 

 by which the motion is given to the upper, and com- 

 municated to the under roller. 



Fig. 12. represents one of the modes of applying the 

 power of the wheel and pinion for driving the rollers: 

 A a pinion fixed to the cheek of the press, which acts 

 in the teeth of the wheel B, which wheel is fixed to 

 the spindle of the upper roller C. A cross with eight 

 spokes DD, is fixed to the spindle of the pinion A, by 

 which the motion is communicated. This application 

 of the wheel and pinion is certainly a considerable im- 

 provement, but it has its disadvantages. The chief of 

 these are, that the pinion cannot be placed at a suffi- 

 cient distance from the spindle of the upper roller, so 

 as to admit of a wheel of sufficient diameter for it to 

 act in to give the requisite power. Another di. ad- 

 vantage is the great length and number of the levers, 

 which renders the action too slow for common work. 

 We give the following description and representation, 

 (Fig. 13.) of a neat, useful, and at the same time a 

 very powerful press, which remedies these defects, 

 and which has been in use for upwards of twelve years 

 without requiring any repair. It is made wholly of 

 cast iron, under the direction of Mr. Lizars of Edin- 

 burgh. Its chief qualities are its durability the 

 compactness of its form the mode of applying the 

 power of the pinion to the wheel seen in the engrav. 



VOL. XVII. PART I. 



ing, instead of its being placed at the cheek of the * 

 , us shown in Fig. 12. and its cheap '.. 



the great tize of plate which its dimensions are 

 calculated to take in. From an examination of the 

 representation given in the accompanying plate, it will 

 appear evident that !>^y the mode of fixing the pinion, 

 and from the great diameter of the \\het-l into which 

 it acts, greater power is obtained; and from the pin- 

 ion being worked by a winch-handle, greater unifor- 

 mity and dispatch is given when required in common 

 work. There is also a convenient apparatus for fix- 

 ing the cloths in cases where the plate is too large to 

 admit of the length of the cloth .being warped round 

 the roller and fixed to it. This apparatus is seen at A, 

 Fig. 13. where the dotted line represents the cloths 

 warped in a triangular form round the roller of the 

 press, and extending to the two small rollers b L t which 

 the cloths make to revolve along with the roller of the 

 press. The diagram, Fig. 14-. will convey a more perfect Ifig- 1*. 

 idea of this apparatus, A A, the two small rollers, round 

 which and the upper roller of the press the cloths b b 

 revolve, when the press is set in motion, d d represent 

 two small screws, which are so contrived as to slacken 

 or tighten the cloths when required. In Fig. 13. B re- 

 presents the plank upon which the copperplate rests ; 

 it is also made of cast iron, and supported upon the 

 small narrow rollers c. 



This press is calculated to print a plate the size of a 

 sheet of double elephant paper, and costs about 40. 



The following description of I\Ir. Perkins's new 

 presses, and the representations Figs. 15 and iC. are 

 extracted from Newton's Journal of Artt. 



*' Fig. 15. shows an improved steel or copperplate, Fig. 15. 

 or block printing press. The principal improvements 

 consist in a new method of heating the plate or block ; 

 in the use of a tympan for the purpose of saving the 

 cxpence of making the plates or blocks any larger 

 than is necessary to receive the engraving, as well as 

 to save ink, and also time and labour in changing the 

 plates or blocks. The manner in which these objects 

 are effected, will appear from Figs. 1 5 and 16. AA, &c. 

 is the cast-iron frame of the press; B the. upper cast-iron 

 roller, on the axis of which is fixed the wheel C, with 

 handles around it for the workman to pull by ; D the 

 lower cast-iron roller, EF the bed of the press, made 

 partly of cast-iron and partly of wood ; the part E is of 

 cast iron, the better to resist the pressure of the roll- 

 ers, and to convey the heat employed to the warm plate 

 or block; the plate or block G is fixed upon the bed, by 

 means of screws passing through counter-sunk holes 

 made in the bed from the under side of it, aud into 

 screw holes made partly through the plate or block it- 

 self. The tympan H is a wooden frame, covered 

 with copper, and turned into hinges 1 1, and having an 

 aperture in it large enough to enclose the plate or 

 block, the sides of which aperture are made feather- 

 edges, so as to overlap the bevelled edges of the plate 

 or block, and prevent them from soiling the paper. 

 The cast-iron part of the bed of the press, with the 

 plate or block upon it, is heated by means of a block 

 of cast iron J , which is supported upon the plate K, 

 with turned up edges, and which b!ock is removed and 

 replaced by another from time to time as it cools. In 

 use, the frame of the press is inclined, the front end 

 resting upon the floor, and the other being raised by 

 two screws passing through screwed holes in the sill 

 of the press frame, one of which screws is shown at 

 L. The intention of this inclination is to cause the 

 bed to return after the impression is made of its own 



Y 



