All About Offset Printing Process And Its Uses

Offset printing is among the most dominant industrial printing techniques and is popular for printing a variety of flat surface products like cards, books, stationery, magazines, leaflets, brochures, etc. Offset printing is also a favorite among printers for packaging prints like boxes or cartons and has been a conventional choice since the 1950s. What happens in offset printing?
In this technique of printing, the inked image is transferred (hence the name offset) to the rubber blanket using a plate and then finally, to the printing surface.

When combined with the lithographic process, it can produce superior results. The modern web process has become more famous and supplies a large reel of paper to the press in different parts and the press prints through this paper as the paper goes on through the press.

How does offset printing work?
Offset printing is actually called Offset Lithography and each of the terms used in the phrase detail the two processes that comprise the technique.

Lithography
In this printing process, the image area, as well as the non-image area, are on the same plane. This means the surface source of the print is completely flat. This particularly helps, thanks to the useful chemical principle. The offset print ink has an oily composition which repels water. The plane with the image area is lipophilic (accepting ink) and the non-printing areas are hydrophilic (oil-repellent but accept water).

In some offset litho presses, dry offset or waterless offset technique is also used to avoid the water-based dampening system.

Offset
Offset literally means that the image which is not printed or transferred (offset) from the lithographic printing plate to the paper. Instead, the inked image is printed from the surface to a rubber blanket and then finally to the printing surface to produce the intended output.

Components of an offset printing press

An offset press with sheet supply comprises:
1. The sheet control system to supply the paper to the press consistently and smoothly.
2. Printing units (1-10) to print colors on a sheet. 4 printing units (Black ink, Cyan, magenta, and yellow) alone can print a full-color text and images. Another unit may be added for varnish or metallic ink.

The printing unit usually has an inking system, dampening system, plate along with the blanket and the much-needed impression cylinders.

Sheet-fed offset and web-fed offset
Sheet-fed offset means the printing press that has sheets of paper supplied to it through a feeding system. This feeding system has a suction bar that lips and drops the sheets smoothly and consistently into the press.

The main uses of the sheet-fed system are for short run and printing magazines, letters, commercial printing, brochures, etc. Mechanical registration is used by the sheet-fed press to ensure that the same imagery is produced in the same position on all sheets supplied to the press.

Web-fed offset means supplying rolls or webs of paper to the press for printing. This method is famous for printing long-run printing jobs like for requirements of five or ten thousand impressions. Newspapers, books, ads, magazines (long run) are often printed using offset web printing.

The two categories of offset web printing are coldset and heatset offset web presses. In Cold web offset printing, the ink dries via paper absorption but in heatset, drying lamps or heaters are used to dry and set the inks.


By: Kim Smith

Inkprint is an Online Print Shop: the Best destination for Online Digital Printing Services in India. Excellent quality Online Digital Printing for Business Cards, Flyers, Postcards, Catalogs, Letterheads, Banners, Posters, Brochures etc. As a pioneer in Online Printing, Offset Printing press and Digital Printing in India and in Delhi.

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Article Tags: Digital Printing , Offset Printing , Online Printing , Online Printing India , Printing Services.

Submitted On Jul 09, 2018. Viewed 25 times.

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