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Rotary screen Printing is said to be one of the revolutionary developments in textile printing. It was introduced in 1963.
- A printing machine that utilizes seamless cylindrical screens made of metal foil was developed in Holland.
- The rotary Screen Printing machine resembles very much the automatic flat-bed screen printing machine is all aspects except the rotary screen section.
- In rotary screen printing, perforated circular metal screens are used for printing instead of the flat screens.
- It is suitable for printing any type of fabric of any construction including knitted fabrics.
Method:
Rotary screen printing is different from the other methods of screen printing in several important respects.
The main features of the machine are: Each screen is independently driven; Printing paste is fed by special pumps individually to the different screens and the print paste level in the rotary screen is automatically and constantly controlled.
- The machine employs a rotary screen for each colour.
As the fabric to be printed is fed under uniform tension into the printer section of the machine.
Back of the cloth is usually coated with an adhesive, which causes it to adhere to a conveyor blanket.
The fabric passes under the rotating screens through which the printing paste is automatically pumped from pressure tanks. The transfer of the printing paste through the perforations of the screen onto the cloth is governed by specially designed squeegee blades. A squeegee in each rotary screen forces the paste through the screen onto the fabric as it moves along at rates of upto 100 yards/min. it is also possible to lift the screens automatically whenever the machine stops so that no stop marks are produced. The cloth then passes into a oven, curved to set the colour and washed.
Types of fabrics that are rotary screen printed are:
Typical products include apparel, Sleepwear, Sheeting and Shirting, Curtains and upholstery. Carpets can also be printed in rotary screen printing machine.
Characteristics:
- Rotary screen prints are difficult to distinguish from roller prints; one difference is the maximum size of the design repeat.
- Rotary screen prints have a maximum design repeat of 36 inches long compared to 16 inches for roller prints
- The maximum number is 16 for a rotary screen prints.
- The colourants on a rotary screen prints lines closer to the fabric surface.
- They have the brighter colours than roller – Printed fabrics with same amount of Colourant applied.
Merits and Demerits:
Merits:
- As many as 24 colours can be printed by this method.
- Joint marks which are perceptible in flat bed and hand screen printing methods are totally absent in rotary printing.
- The prints produced are free from smudging effect
- Production of printed material by this material is highest when compared to flat bed (or) roller printing.
- Half tone effects and vertical lines can be produced very successfully by this method.
Demerits:
- This method is not economical for short runs of the fabric due to high cost of engraving the screen.
- The size of the repeat of the design is limited to about 65cm. Which is less than that of a hand screen.
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