In this type of printing, the screen is wrapped on a metal cylinder. The solution of the color is inserted from one end of the cylinder. This roller rotates by mechanical method. When the cloth is to be printed then this cylinder will sit on the cloth Goes and starts to rotate, so that the entire screen on the fabric (which is wrapped on the cylinder) is printed. In this printing, the color of the screen is the same as the screen is needed. The cylinders are wrapped on this process by about 100 meters /
Part Of The Rotary Printing Machine
Some of the most important devices fixed on the rotary screen printing machine is as follow
(A) Feed Device: This consists of guide rollers with or without scary and a pair of clothing guider it is meant to feed fabric
(b) Vacuum Cleaner: Vacuum cleaner removes any loose lint or fluff from the surface of the fabric
(c) Gluing Device: This device consists of an expander roller and a pressing
(d) Printing Bed: Printing is carried out by circular nickel perforated standard size of the screen (Mostly 640 mm circumference) which are mounted on the sized screen ( flatbed of the blanket which is an endless washable darex type.
(e) Feeding Pumps: Colored feeding is carried out into the screen, by non- reversible type pumps made of stainless steel.
(F) Drier: Printed fabric is fed by means of a systematic conveyer belt to the hot air drier which consists of a high-grade beat insulated hot air chamber equipped with a powerful radial fan and exhaust fan. Drier has a plaiter at the delivery end.
(G) Squeeze System: The important part of the machine is a squeeze system that feeds the color of the fabric. There are mainly two systems:
(i) pneumatic squeeze system working with a doctor blade
(ii) Magnetic rod system working in the influence of the magnetic field’. Modified squeeze consists of plastic tip rubber blades. Different sizes of squeezes are used for various types of prints such as cutlines, blotches, etc.
Advantages of Rotary Screen Printing:
Production of printed material by this method is the highest ás compared to roller printing or automatic flatbed printing method;
As many as 24 colors can be printed by this method but 8 to 10 colors can te printed easily, Joint marks which am perceptible in flat-bed and hand screen printing methods are totally absent In rotary printing.
Hall tone effects and vertical! lines can be produced very successfully by this method; The prints produced are froe from the smudging effect which is quite severe in roller printing.
Disadvantages of Rotary Screen Printing :
The method is not economical for short runs of the fabric due to the high cost of engraving of the screens; The size of repeat o! the design is limited to about 55 cm. which is less than that of a hand screen.