There are many techniques adopted to print on various substrates, but two most commonly used techniques are flexographic printing and gravure printing. Flexo and gravure printing processes are as follows:- In flexo printing an image carrier made of polymer is used, which may be in shape of sleeve, or cylinder or plate. This carrier is engraved with design of final print. Ink is transferred from inkwell onto image carrier, and then it is printed on the substrate. In gravure printing ink is applied to substrate, through metal plate which is mounted on a cylinder. Image to be printed is laser etched into metal plate, this method gives good quality and precise results.
Printing ink has three basic products in it, they are pigments, vehicles and binders and extenders and plasticizers. In recent years there is tremendous growth in packaged foods, and this brings growth in printing ink industry. As all the packaged foods need printing on it, and the ink used on packages should not contain any harmful chemicals which may contaminate food items. There are certain rules and regulations, which should be followed by the manufacturers of printing ink for food packaging. Apart from this printing ink is also used for newspaper printing, publishing, and commercial printing. Printing ink industry has strong growth in recent time and there is large number of printing ink manufacturers in India.
Gravure and flexo printing can be compared on the basis of cost and lead time, substrate, inks, environmental considerations and quality. Image carriers used in flexo printing are cheaper than the image carriers used in gravure printing. Flexo printing can be done on porous as well as non-porous substrates, so it ideal technology from paperboard to films. For packaging printing also flexo printing technology is used. Flexo printing can be done with variety of inks, whereas for gravure printing a limited number of inks can be used. Environment point of view, flexo printing is better than gravure printing. Although, gravure was considered for fine work, but flexo technology is now improved to give prints with good resolution, and is more suitable for printing works.
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