Buying Used Printing Machinery from Roberts Graphics.
Here at Roberts Graphics we make the process of buying used printing machinery as simple as possible. Visit our main website to view our current stock or if you know what you want but can’t find it or simply don’t have the time to search then give us a call and we will be happy to source the printing machinery that matches your needs.
What are the different types of printing machinery?
Offset Printing Machinery:
Offset printing replaced expensive and labour intensive raised metal type in the printing process with a photographic based system that uses a flat rubber mat to transfer an image onto paper. It was the predominant system for commercial printing from about 1960 into the beginning of the 21st century.
Offset printing works because of hydrophobia, oil and water don't mix. A photographic image in created on a flat metal printing plate that has a grainy surface that holds liquids well. The 'image area' on that plate has a coating that is receptive to oil-based printing inks while the uncoated areas tend to accept water and repel ink. Roller systems on an offset press supply measured amounts of ink and water to that plate allowing an image to form on it's flat surface. Other rollers transfer the image from the metal plate to a cylinder covered with a flat rubber mat called a 'blanket.' Finally, paper is delivered past the blanket cylinder and squeezed slightly against it by a third 'impression' cylinder. The ink transfers from the blanket to the paper and you have printed!
Web Offset Printing Machinery:
"Web-fed" refers to the use of rolls (or "webs") of paper supplied to the printing press. Offset web printing is generally used for runs in excess of 10 or 20 thousand impressions. Typical examples of web printing include newspapers, newspaper inserts/ads, magazines, catalogs, and books. Web-fed presses are divided into two general classes: "Cold" or "Non-Heatset," and "Heatset" offset web presses, the difference being how the inks that are used dry. Cold web offset printing is air dried, while heatset utilizes drying lamps or heaters to cure or "set" the inks. Heatset presses can print on both coated (slick) and uncoated papers, while coldset presses are restricted to uncoated paper stock, such as newsprint. Some coldset web presses can be fitted with heat dryers, or ultraviolet lamps (for use with uv-curing inks).
Sheet Fed Offset Printing Machinery:
"Sheet-fed" refers to individual sheets of paper or paperboard being fed into a press. A lithographic ("litho" for short) press uses principles of lithography to apply ink to a printing plate, as explained previously. Sheet-fed litho is commonly used for printing of short-run magazines, brochures, letter headings, and general commercial (jobbing) printing.
Some Usefull Links:
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