Rotary printing

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In offset printing and rotogravure printing , rotation printing is only used when printing is carried out on rolls. In letterpress printing, a distinction is made between web-fed rotary printing and sheet-fed rotary printing .

A sheet-fed rotary press consists of the feeder, the printing unit and the delivery. Turning devices, coating units and dryers can be installed between and after the printing units. The machine achieves an output of around 7,000 prints per hour. Individual sheets are processed in it. Individual sheets are separated from the stack and fed to the printing units with a front and side system. During printing and transport within the machine, gripper bars hold the front edge of the sheet and thus transport it from gripper system to gripper system. With up to four inking units, multi-color prints are possible in one operation. The printing forms are either curved plastic clichés or winding plates.

Because the cylinder and the paper web are constantly rotating in one direction, a faster work rate can be achieved in web- fed rotary printing than in sheet-fed printing machines. This is mainly used when printing long runs.

A web-fed rotary machine consists of a web unwind, a web infeed unit, the printing units, a dryer, a cooling device and a connected folder.

Web-fed rotary presses have an output of around 35,000 cylinder revolutions per hour and, due to their speed, are mainly used for printing newspapers. The paper web is drawn in by a feed unit and printed directly from the roll. For this reason there is no gripper system as in the sheet rotation process. This has the advantage that almost the entire cylinder circumference can be printed. Only the lateral system and the web tension are checked. Often these machines are built in the tiered construction. The finished paper webs are transferred directly to further processing, i.e. cut, folded and collated immediately after printing. Only the finished product leaves the rotary machine.

Web-fed rotary machines are mainly used in offset printing. They are used for printing daily newspapers , consumer magazines and magazines with high print runs . These machines can produce around 60,000 prints per hour.

literature

  • Hubert Blana: The production . 4th edition, Saur, Munich 1998, ISBN 978-3-598-20067-0 (= basic knowledge of the book trade - publishers , volume 5).
  • Bernhard Laufer: Basic knowledge of typesetting, printing, paper . 2nd edition, Verlag Buchhandler heute, Düsseldorf 1988, ISBN 3-920514-19-X (= the specialist knowledge of the bookseller ).
  • Hans Jürgen Scheper: Examination knowledge printing technology. Pre-press, post-press, aids for schools and training for deepening, repetition and targeted exam preparation . Verlag Beruf und Schule, Itzehoe 2005, ISBN 978-3-88013-623-6 .