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V. Choose two or three different types of fonts and compare them by their design.

UNIT 4 Pre-Print and Printing Processes

Text 1 Digital Pre-Press Stage

Without a doubt, systems for the digital mounting of whole print sheets and for the exposure of whole sheet films are on the advance Future developments in the computer-to-plate direction are already foreseeable at present and are partially already reality Against this background the digitization of the measuring elements required for printing, such as quality control strips, proof strips or register marks, is an absolute necessity Heidelberg measuring elements (quality control strip system Heidelberg GS, CPC proof strip, register marks for CPC 41 and for CPC 42) are now available in digital form They are pro­grammed in PostScript® and suit all layout programs, RIPs and imagesetters based thereon The digital measuring elements are considerably easier to position than film parts, which means that the print formes can be produced at lower cost.

In addition fully digitally pro­duced print sheets are by their very nature free from mounting imprecisions, in particular differ­ences between images and the register control marks, which increases still further the utiliza­tion of the digital measuring elements when setting the print­ing press.

These digital measuring elements are available on large imageset­ters from Linotype-Hell and other renowned suppliers Distribution and service is effected via the manufacturers of imagesetters.

Fast Makeready

Finally, automated cleaning devices get the plates ready to start printing. The entire process is fully automated and takes only about 15 minutes! While the plates are being imaged, the Quickmaster DI operator is free to make other preparations for the pressrun. The inherent versatility of the press permits preloading of the paper, among other things. Changing formats could hardly be easier, requiring only a few quick adjustments to be made with the central format setting at the feeder. All four printing units can also be centrally adjusted to the thickness of the stock being printed on, using a handwheel at the delivery.

Text 2 Direct Imaging

Direct Imaging is based on ad­vanced laser technology. First the Raster Image Processor (RIP) integrated in the Quickmaster DI converts PostScript Level 2 data into bitmap files corresponding to the four-color separations. These are in turn used to control infrared laser diodes in the press. An Ethernet link is all it takes to directly transfer digitized docu­ments to the Quickmaster DI, bypassing the stages of stripping, film exposure and platemaking. The light emitted by the laser diodes is led via fiber-optic cables to lenses that focus them into a single, precise beam of light. This high-intensity beam burns very small, sharp-edged depres­sions in a special multilayer plate. Analogously to other waterless offset processes, this reveals the underlying backing material, which accepts ink Everywhere else (in the nonimage areas) the ink-repelling silicone layer remains intact. The special plate material used in the Quickmaster DI allows the press to operate without the dampen­ing solution required in conventional offset printing. Waterless printing provides full, intense colors and is overall more opera­tor-friendly.

Two different resolutions are available for imaging the plates in the press. 1270 dpi and 2540 dpi- The 1270 dpi resolu­tion (corresponding to 50 dots per millimeter) is sufficient to print a 150 Ipi screen in good offset quality. The higher resolution can be used to good advantage on jobs that pose special requirements, such as delicate gradients.

І. Answer the following questions:

1. What is the base for Direct Imaging?

2. How do the laser diodes work?

3. Why can the press operate without the dampening solution?

4. What resolutios are there in the press?

ІІ. Find in the text equivalents of the terms:

Лазерний діод, a)

керуючі сигнали, b)

додрукарська садія c)

оптоволоконний кабель

до друкарська садія,

репродукування,

монтаж,

копіювання на форму, ,

багатошарова друкарська плівка,

сухий офсет,

зволожуючий розчин,

роздільна здатність.

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