Types of rotary presses
Release time:
2023-03-14 16:52
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Today, there are three main types of rotary printing presses: offset (including web offset), rotogravure and flexographic (short for flexographic). Although these three types use cylinders for printing, they differ in their methods.
In offset lithography, the image is usually applied chemically to the plate by exposing the photosensitive layer to the plate. Lithography is based on the fact that water and oil do not mix, which allows the lithographic process to work properly. In the case of printing plates, the wettable surface (non-image area) can also be called hydrophilic while the non-wettable surface (image area) is called hydrophobic.
Gravure printing is the process of etching small cells or holes into a copper cylinder capable of being filled with ink. All colors are etched at different angles so that each color is placed in the proper position to provide the proper image when printed.
Flexographic printing is a letterpress system in which a raised image is usually formed on a polymer-based plate.
In philately, rotogravure-printed stamps are sometimes a different size than stamps printed with lithography. This occurs because the stamp images are further apart on the rotary press, which makes the individual stamps larger (typically 0.5 to 1 mm (0.020 to 0.039 in.).
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William Nicholson patented the rotary press in 1790. The rotary press itself was a development of the cylinder press, which was also patented by William Nicholson, invented by Beaucher in France in the 1780s and Friedrich Koenig in the early 19th century.
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