Printing Technology & Digital printing

Digital printing accounts for approximately 9% of the 45 trillion pages printed (2005 figure) around the world.

Printing at home or in an office or engineering environment is subdivided into:

* small format (up to ledger size paper sheets), as used in business offices and libraries

* wide format (up to 3' or 914mm wide rolls of paper), as used in drafting and design establishments.

Some of the more common printing technologies are:

* blueprint—and related chemical technologies.

* daisy wheel—where pre-formed characters are applied individually.

* dot-matrix—which produces arbitrary patterns of dots with an array of printing studs.

* inkjet—including bubble-jet—where ink is sprayed onto the paper to create the desired image.

* laser—where toner consisting primarily of polymer with pigment of the desired colours is melted and applied directly to the paper to create the desired image.

* line printing—where pre-formed characters are applied to the paper by lines.

* heat transfer—like early fax machines or modern receipt printers that apply heat to special paper, which turns black to form the printed image.

Vendors typically stress the total cost to operate the equipment, involving complex calculations that include all cost factors involved in the operation as well as the capital equipment costs, amortization, etc. For the most part, toner systems beat inkjet in the long run, whereas inkjets are less expensive in the initial purchase price.

Professional digital printing (using toner) primarily uses an electrical charge to transfer toner or liquid ink to the substrate it is printed on. Digital print quality has steadily improved from early color and black & white copiers to sophisticated colour digital presses like the Xerox iGen3, the Kodak Nexpress and the HP Indigo Digital Press series. The iGen3 and Nexpress use toner particles and the Indigo uses liquid ink. All three are made for small runs and variable data, and rival offset in quality. Digital offset presses are called direct imaging presses; although these receive computer files and automatically turn them into print-ready plates, they cannot insert variable data.

Small press and fanzines generally use digital printing or more rarely xerography. Prior to the introduction of cheap photocopying the use of machines such as the spirit duplicator, hectograph, and mimeograph was common.

For every newspaper, book, or other printed product, there is a production crew laboring behind the scenes, from printing press operators to bindery workers. As a printing technology major, you’ll learn the skills necessary to plan, prepare, and complete print jobs, from assembling film to operating printing equipment to cutting and collating the finished product.

Most programs offer both old-school and new-school techniques, so by the time you graduate, you’ll be prepared for hands-on production work as well as cutting-edge desktop publishing.

source:internet only