588 



CALICO-PRINTING 



adjusting screws, bring thorn into more or loss intimate contact with the rollers 8, 

 and consequently vary the charge of colour at pleasure. 



The blanket, backcloth, and fabric are circulated as follows : At the four angles 

 formed by the three tables, B, are rollers, 1, armed on their surface with needle-points, 

 which prevent the cloths from slipping as they pass round, and thus secure the regular 

 movement of the stuff to be printed, a movement determined by the toothed wheels 

 21 (fig. 330) fixed at the extremities of the axes of these rollers, o is a roller for 

 stretching the endless web, resting with the two ends of its axes on two cushions 

 forming the extremities of the screws 12, by which the roller can be pushed further 

 out when required, to give the cloth the necessary tension. H is another tension 

 roller, supporting the blanket and backcloth. K is a roller which serves similar 

 purposes for the blanket, the backcloth, and the fabric in course of being printed. 

 T, the blanket, which in its course embraces the scmicircumference of the roller o, 

 passes over the roller n, and behind K, to circulate round the cylinders 1, and over 

 the surfaces of the tables B. L is a cylinder from which the backcloth is unwound, 

 being- first stretched by the roller H, and then smoothed by the scrimping bars 13, 

 from which it proceeds to join the blanket on arriving at the roller K. M a roller, 

 from which the fabric to be printed is unrolled by the movement of the machine, first 

 passing over the scrimping bars 14, and joining at K the blanket and backcloth, which 



330 



it accompanies in their course till it arrives at the roller G, when it separates and 

 passes off in the direction of the line N, to the hanging rollers, where it is dried. 



The machine is put in movement, either by a man with a winch-handle, or by 

 power communicated by a strap which passes over the pulley 18. This pulley has 

 several diameters, so as to give several speeds ; it is loose on the driving shaft, and 

 carries catches which lock into those of a sliding catch-box on the shaft, when the 

 machine is to be put in movement. The movement of the machine is intermittent 

 because the printing is intermittent ; moreover, it must be so regulated that the fabric 

 advances a distance exactly equal to the breadth of the blocks, and that it moves 

 forward whilst the sieves are charged with colour from the rollers 8 8. This result 

 is obtained by means of a regulator, or dividing wheel 20. The wheels 21, fixed at 

 the extremities of the axis of the cylinders 1, and having each the same number of 

 teeth, receive their movement from a central wheel toothed in the same manner, and 

 placed behind the wheel 20. The last receives an alternating motion from a rack, 

 24, fixed in a copper piece, 25, and which rises and falls alternately, being keyed at 

 its lower end to one of the spokes of the wheel 28. By varying the position of the 

 point at which the end of the rack is connected with the spoke 26, the length or 

 range of its movement is proportionally changed, and more or less of the teeth of 



