CALICO-PRINTING 



585 



326 



three rollers, /^ h, the lower of which,/, is in contact with the colour-roller i in the 



colour-trough K. On the axle of the roller i a pulley wheel is fixed, which allows the 



roller to be turned by 



a band from any first 



mover ; or the roller may 



receive rotatory motion 



by a winch fixed on its 



axle. On this said axle 



there is also a toothed 



wheel, taking into d an- 



other toothed wheel on 



the axle of the roller/; 



hence, the rotation of the 



colour-roller i in the one 



direction will cause the 



roller / to revolve in the 



opposite, and to carry forward the endless web, e e, over the elastic diaphragm, the 



web taking with it a stratum of colour received from the roller i, equally distributed 



over its surface, and ready for the printer to dip his block into. 



The axles of the rollers /and g turn in stationary bearings ; but the axle of h is 

 mounted in sliding nute, which may be moved by turning the screws m, for the purpose 

 of tightening the endless web. The axle of the colour-roller i turns in mortises, and 

 may be raised by screws n, in order to bring its surface into contact with the 

 endless web. To prevent too great a quantity of colour being taken up, the endless 

 web passes through a long slit, or parallel aperture in the frame o, which acts as a 

 scraper or doctor, and is adjustable by a screw p, to regulate the quantity of colour 

 carried up. The contents of the vessel a, and the colour-trough K, may be discharged 

 when required by a cock in the bottom of each. This 

 contrivance did not come into general use, but is still 

 employed at some print works in England. The Tobying 

 sieve is a mode of applying with one block several 

 colours at once, whereby the cost of several blocks is 

 saved, and, what is of more consequence, the cost of 

 labour is very much reduced, as one printer produces 

 the same result as the combined efforts of several. 



Whenever designs are composed of coloured parts, 

 where each colour lies separate, and where the outlines 

 of the coloured parts are not too close together, a sieve 

 of the following construction is made use of (./S^.327). 

 A block of wood is scooped out in hollow compart- 

 ments E, which vary in size and number according to 

 the number and extent of the shades to be printed; 

 these compartments communicate by tubes B at the 

 bottom, with reservoirs A, at the sides of the sieve, over 

 the compartments is then stretched tightly a woollen 

 sieve ; the surface of this cloth is cemented with melted 

 resin string about fth of an inch thick, following the 

 configurations of the compartments ; the use of this is 

 to prevent the colours mixing and becoming blended 

 at the edges. Colours are now put in the reservoirs, 

 which are kept filled up above the height of the cloth, 

 so that a gentle pressure is exerted against the under 

 side of the sieve. The colours are made of such a 

 thickness as to pass through the cloth, and keep the 

 upper surface moist, but still not too thin, or they would 

 spread when printed. The sieve being thus prepared, 

 the block is furnished with guides, which, working 

 against the sides of the sieve frame, constrain the block 

 to bo always dipped in one place, and thus each part of the pattern finds itself 

 furnished with its proper colour. Sometimes the compartments for the colours are 

 made of metal when required to be durable, so as to serve- for a large number of 

 pieces of the same pattern. 



When colours are required to melt into one another, technically called rainbowed 

 (fondus, Fr.), the following apparatus is used: A A (fig. 328) is a rectangular frame 

 of wood, about 6 inches deep, 2 feet long, and about 1 foot broad. On this frame is 

 stretched, by means of small hooks, a woollen cloth, and the frame then laid on the 

 elastic surface of the usual swimming tub, the. cloth downwards and pasted or gummed 



