OUGD504 - SB01 - Printing Methods

OUGD504

SB01

Printing Methods

Offset

In offset lithography a printing plate, which is most often made from aluminum, contains an image of the content that needs to be printed. When the plate is inked, only this image part holds ink. That inked image is subsequently transferred (or offset) from the plate to a rubber blanket and then to the printing surface. The process can be used to print on paper, cardboard, plastic or other materials, but these have to have a flat surface. For higher volume work offset presses use rolls of paper. It is so fast that the printed paper needs to be force dried. Offset is the most widely used printing technique for an extensive range of products such as books, newspapers, stationery, corrugated board, posters, etc. 

Flexo

In flexography the content that needs to be printed is on a relief of a printing plate, which is made from rubber. This plate is inked and that inked image is subsequently transferred to the printing surface.  The process can be used to print on paper as well as plastics, metals, cellophane and other materials. Flexo is mainly used for packaging and labels and to a lesser extent also for newspapers.

Inkjet 

In an inkjet printer the image that needs to be printed is created by small droplets of ink that are propelled from the nozzles of one or more print heads. Inkjet devices can print on a wide range of substrates such as paper, plastic, canvas or even doors and floor tiles. Inkjet printing is used a lot for posters and signage. It is also economical for short run publications such as photo books or small runs of books. In-line inkjet printers are sometimes combined with other types of presses to print variable data, such as the mailing addresses on direct mail pieces. 

Xerography

In xerographic printers, such as laser printers, the image that needs to be printed is formed by selectively applying a charge to a metal cylinder called a drum. The electrical charge is used to attract toner particles. These particles are transferred to the media that is being printed on. To make sure the toner is fixed properly, the substrate passes through a fuser that melts the toner into the medium. Laser printers are not only used in offices but also for small run printing of books, brochures and other types of document. These printers are also used for transactional printing (bills, bank documents, etc) and direct mail.

In short run small format (A3 size) printing, digital is taking over from offset for both color and B&W printing. Quick printers and copy shops print digitally on presses from vendors like Xerox, HP, Canon, and Konica Minolta. 

Labels are also increasingly being printed digitally. 

Billboard and point-of-sale or point-of-purchase jobs are being done by wide-format inkjet devices.

There is a wide range of small format printers used to print on phone cases, mugs and other products.

In book printing publishing companies start to rely more on print-on-demand. 

Dye-sublimation

Dye-sublimation is a printing process in which heat is used to transfer a dye onto the substrate. Dye-sub printers are mainly used for printing on textiles, for proofing and for producing photographic prints. Some printers can print on a variety of materials such as paper, plastic, and fabric.

Gravure

Also known as rotogravure, this is a technique in which an image is engraved into a printing cylinder. That cylinder is inked and this ink subsequently transfers to the paper.  Gravure is used for high volume work such as newspapers,  magazines, and packaging. Gravure is gradually losing market share to offset for publication printing and to flexo for packaging applications.

Screen printing

As its name implies, this printing technique relies on a screen, which is a woven piece of fabric. Certain areas of this mesh are coated with a non-permeable material. In the remaining open spaces ink can be pushed through the mesh onto a substrate. The advantage of screen printing is that the surface of the recipient does not have to be flat and that the ink can adhere to a wide range of materials, such as paper, textiles, glass, ceramics, wood, and metal.

For my publication I will use the laser printers within the college. However, if the book was to be printed on a large scale I would chose to use offset lithography (commercial considerations vs. access to resources) as it is fast and cost effective. The front cover is make of mount board which is too think to put through the digital print facilities in the university, therefore I have chose to screen print the title. If the product was to be mass produced I would consider using lithography or flexo to print on this material.