An Overview of Textile Printing

Nadia Sultana
B.Sc. in Textile Engineering
Major in Apparel Engineering
Textile Engineering College, Zorargonj, CTG

Introduction:
Printing is the process which is applying color to fabric in definite patterns or design. In properly printed fabrics the color is bonded with the fiber, so that to resist washing and friction. Textile printing is related to dyeing but in dyeing properly the whole fabric is uniformly covered with one color whereas in printing one or more colors are applied to it in certain parts only and in sharply defined patterns. Colorants used in printing contain dyes thickened to prevent the color from spreading by capillary attraction beyond the limits of a pattern or design. It is part of wet processing which is carried out after pre-treatment of fabric or after dyeing. It is done for producing attractive design on the fabric. Usually printing is performed on one side of the textile. Different printing methods can be applied to transfer the dyestuff and chemicals to the surface of the fabric.

Methods of Fabric Printing:
Following methods can be used for printing of a fabric –

Block printing
Roller printing
Screen printing
Flat screen printing
Ink jet printing
Warp printing
Photo printing
Transfer printing

Above printing methods are described briefly:

1. Block printing: Block printing is the process of printing pattern by means of engraved wood blocks. It is the earliest, simplest and slowest of all methods of textile printing. Wooden blocks for textile printing maybe made of box, lime, holly sycamore, plane or pear wood, the letter three being planned quite smooth and perfectly flat ,next has the design drawn upon or transferred to it. It is used only at small scale or in cottage and is not used at industrial scale because of less flexibility and productivity.

2. Roller printing: Roller printing engraved roller printing is a type of machine printing that involves the use cylindrical rollers to transfer ink onto fabric or other materials. The rollers are coated with the desired ink color and then pressed against the material, transferring the ink to create a design or pattern. Roller printing is a continuous printing process, making suitable for producing large quantities of printed fabric in a short amount of time.

3. Screen printing: Screen printing is a type of textile printing that involves pushing ink through a stencil or screen onto fabric. The screen printing is the most commonly used printing method in textile industry. Screen printing is versatile printing method that can be used to produce a wide range of designs on a variety of materials, including fabric, paper, plastic and more. Screen printing involves passing the print paste onto a fabric through a mesh or screen which has some open and some blocked areas according to the desired print pattern. The print design obtained on the fabric depends on the pattern of the open areas of the screen.

4. Flat screen printing: The fabric is fixed to a blanket or black grey on a printing table where the screen are put on. The print paste is spread across the screen by hand with a squeegee blade forcing the paste through the screen. The screen properties are very important. Stable screen are necessary. The frames used for flat screen printing are made of wood or preferably of metal.

5. Ink jet printing: Ink jet printing is a type of computer printing that recreates a digital image by propelling droplets of ink onto paper and plastic substrates. Ink jet printing is a non contact printing system because the print head does not touch the substrate surface. The dyes to be printed are in the form of inks rather than pastes and the viscosity of the inks is low compared to other printing system. The quality of an inkjet printing is very much influenced by the physico chemical properties of printing ink.

6. Warp printing: warp printing is roller printing applied to the warp yarns before they are woven into fabric. Printing the warp yarns prior to fabric formation creates warp prints. Fabric is woven with a solid color filling usually white or neutral colored filling yarns. The design effect is often described as soft and shadowed. The motif or print pattern can be simple but is often complex. Warp printing skilled person and person with lot of experience can only do because of the complex details.

7. Photo printing: Photo printing on fabric is very similar to producing. Either black and white or multi colored pattern can be reproduced. In photo printing the fabric is first coated with light sensitive chemical. Any photographs can be printed on to the fabric. The results are same as when printing photographs on paper. The results is similar to that obtained by printing photo sensitive paper for photo copies. Each and every details can be reproduced if the technicians skilful. Any photo graph can be printed on the fabric.

8. Transfer printing: Transfer printing is a printing process in which an image or design is printed onto a transfer paper, which is then applied to a fabric or other material using heat and pressure. Transfer printing is often used to produce high quality images or designs on textile ceramics and other materials.

Process Flow Chart of Textile Printing:

Fabric preparation

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Preparation of printing device

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Printing paste preparation

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Impress on fabric

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Drying the printed fabric

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Fixation by curing

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Washing and soaping

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Finally dry

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Delivery

Preparation of Fabric for Printing:
By washing and bleaching fabric is prepared. For colored it is then dyed. The fabric has always to be brushed, to free it from loose nap, flock that picks up whilst stored. Some fabrics require very careful stretching on a stenter before they are wound around hollow wooden centers into rolls of convenient size for mounting on the printing machine.

Preparation of Colors:
The art of making textile printing both chemical knowledge and experience. For their elements need proper proportion and particular style of work in hand. A color must comply with conditions such as shade, quality and fastness. All printing paste whether containing coloring matter or not are known technically as Colors. Colors are very considerably in composition. A mordant is a metallic salt or other substance that combines with the dye to form an insoluble color.

Conclusion:
The desire to use textile fabrics as a carrier of design for decoration or identification has existed for many centuries. The development of modern equipment and colorant technology has enabled. Textile manufacturers to be able to reproduce highly colored textile designs with excellent colorfastness. This can be performed on a wide variety of fibers and fabric constructions, employing cost effective processes. However, as good as textile-printing technology is today. The processes are continuing to improve. New technologies and new developments in existing methods promise to continue the expansion of the capabilities of textile printing well into the future.

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