PRINTING

Printing

Printing is the art of design by mechanical and chemical application. Printing entails the localized of dye or pigment, the design being created by different color or motives.

Textile Printing:

By the term “Textile Printing” we mean the localized application of dyes or pigments and chemicals by any method which can produce particular effect on the fabric according to the design.

General steps of printing:

1. Printing raw material and grey textile material collection

2. Preparation of textile material for printing by pre-treatment

3. Preparation of printing paste

4. Printing with a certain style and method

5. Drying of the printed fabric

6. Steaming of the printed fabric

7. Printing finishing by after treatment

Printing is the great part of textile coloration. Printing is the older part of textile history. Textile printing is probably best described as an industrial art, having a long printing history and an assured future. Printing has become more dependent on the sciences than it was, but will always be a multidisciplinary activity, requiring more than knowledge of science and technology in case of printing. If you want get total view about printing we must acquire knowledge about 8 terms of printing.

1. Traditional printing methods:

The traditional style of printing originated in India, Egypt, China or elsewhere. The oldest history of printing is not clear. Brunello states that an early variety of cotton dyed with madder around 3000 BC was found in jars in the Indus valley. The block printing is the initial stage of printing. It is the oldest and the easiest method of printing. The perfection of design is very poor. The use of engraved copper printing gave the variation in printing. The performance is better than screen printing. At last Rotary screens printing gave the modern touch in traditional printing methods.

It includes 3 terms,

1 A historical perspective of printing

2 Surface printing methods

3 Engraved-roller printing

2. Screen printing:

Screen printing is an extension of stencilling. Innumerable children experiment with simple stencils by cutting out shapes from card, and brushing or spraying paint or ink through the holes on to paper beneath. Commercial stencil sets for lettering are made of waxed card or metal, and incorporate ties to hold the solid areas together and to prevent the centres of letters such as O or P from falling out. The ties produce unsightly lines across the stencilled letters.

The screen printing include 9 terms;

1 Introduction of screen printing

2 Hand screen printing and semi-automatic screen printing

3 Fully automatic flat-screen printing

4 Rotary-screen printing

5 Design aspects of printing

6 Computer-aided design for printing

7 Screen production of printing

8 The fundamental mechanism of screen printing

9 Non textile applications of screen printing

3. Transfer printing

Transfer printing is the term used to describe textile and related printing processes in which the design is first printed on to a flexible non-textile substrate and later transferred by a separate process to a textile. It may be asked why this devious route should be chosen instead of directly printing the fabric.

Transfer printing includes;

1 Introduction to transfer printing

2 Sublimation transfer of transfer printing

3 Melt and film release transfer of printing

4 Wet transfer printing

4. Carpet and yarn printing

The initial development of the printing of carpet piece goods took place in the UK shortly after the introduction of tufted carpet production, which followed the lead given by the USA from the early 1950s onwards. The manufacture of broadloom tufting machinery expanded rapidly in the period 1956–64, with continuous improvements in sophistication and productivity following the establishment of such firms as British Tufting Machinery, Cobble Bros (subsequently Singer Cobble), Ellison Tufting Machinery and Edgar Pickering of Blackburn.

Carpet and yarn printing includes;

1 Historical development of carpet printing

2 Yarn printing (space dyeing)

3 Carpet printing

4 Printing of carpet tiles

5 Treatments before and after printing

6 Physical factors affecting the quality of printed carpets

7 Selection of dyes and chemicals for printing nylon carpets

8 Printing of carpets tufted from fibres other than nylon

5. Direct print coloration:

Printing can be considered as a controlled form of localised dyeing and, in principle, any dyes used to produce plain-coloured fabric could be used to print that fabric. The same mechanisms of dye fixation apply in both dyeing and printing. Careful selection of appropriate dyes for a particular dyeing process is desirable, however, and selection for printing is essential. The primary reason is that in printing dye solubility is more critical, even more so than for continuous dyeing processes, which admittedly compare closely with printing. Not only is the amount of water in the print paste severely limited but, at the fixation stage, the dye must be redissolved in a small volume of condensed steam.

Direct print coloration includes;

1 Introduction to direct printing

2 Pigment printing

3 Cellulosic fibres printing

4 Polyester fibres printing

5 Cellulose acetate fibres printing

6 Acrylic fibres printing

7 Polyamide fibres printing

8 Protein fibres printing

9 Polyester/cellulose fibre blends printing

6. Discharge, resist and special styles of printing

Discharge and resist styles of printing have been important since the earliest days of textile printing. Knecht and Fothergill gave an excellent account of the many processes of those printing, often developed with considerable ingenuity, that provided a wide range of effects without the advantages of modern dyes. In recent years, modern techniques have made the use of direct printing practicable for many more designs and reduced the necessity of using these styles, but they will always be of significance because the effects obtained are often different and aesthetically superior.

Discharge, resist and special styles of printing include;

1 Introduction and definitions of special printing

2 Discharge printing

3 Application procedures in discharge printing

4 Resist printing

5 Special styles of printing

7. The production and properties of printing pastes:

All the different methods of printing normally require a liquid vehicle, in which the colorant is carried, and only in exceptional cases has it been possible to print dry colorant. In textile printing, the liquid is usually aqueous but in paper printing, as high-speed drying is necessary, more rapidly evaporated non aqueous solvents have been used. The components of the liquid printing paste must include all necessary wetting, dispersing and fixing agents, in addition to the colorants, and may be soluble or insoluble. No separation of insoluble components must occur, and the incorporation of viscosity-increasing protective colloids helps in this respect.

The terms include:

1 The requirements of printing pastes

2 Thickeners of printing paste

3 Raw materials: polysaccharides of printing

4 Viscous emulsions of printing

5 Viscous foams of printing

6 Synthetic-polymer thickeners of printing

7 Print paste theologies

8 Print paste productions

9 Colour shop organization for printing

8. Fixation and after treatment processes of printing

If a typical textile print is washed soon after printing and drying, a substantial part of  the colour is removed. An appropriate fixation step is therefore necessary. Complete fixation can rarely be achieved, however, and the removal of unfixed dye, thickening and auxiliary chemicals in a subsequent washing process is usually required.

The terms include;

1 Introduction to fixation and after treatment processes of printing

2 Pigment prints

3 Steamers for drying

4 Miscellaneous techniques

5 Washing-off processes

6 Washing-off equipment