Content:

Unit 1 Printing techniques

Text 1 Basic printing techniques

Text 2 Letterpress

Text 3 Offset lithography

Text 4 Gravure

Text 5 Other traditional printing techniques

Text 6 Modern printing techniques

Unit 2 Origination

Text 1 Originals for reproduction

Text 2 Reproduction techniques for offset lithography

Text 3 Proofing

Text 4 Electronic page planning

Text 5 Film assembly, imposition and platemaking

Text 6 Origination for letterpress

Unit 3 Typesetting and desk-top publishing

Text 1 Typesetting in metal

Text 2 Photocomposition

Text 3 Desk-top publishing

Text 4 Page layout software

Text 5 Type measurement

Text 6 Typefaces

Unit 4 Paper and ink

Text 1 Ink

Text 2 Paper

Text 3 The paper machine

Text 4 Types of paper

Text 5 Specifying papers

Text 6 Potential problems with paper

Unit 5 Printing processes

Text 1 Digital Pre-Press Stage

Text 2 Direct Imaging

Text3 Fully Automatic Print Preparation

Text 4 Central Remote Control of Ink and Regist

Text 5 Coating and Drying

Text 6 Delivery

Unit 6 Finishing and Binding

Text 1 Finishing

Text 2 Paperback binding

Text 3 Hardback bookbinding

Text 4 Other methods of finishing

Text 5 Packing

Unit 7 Printing units

Text 1 Printing presses

Text 2 Processing machinery

Text 3 Letterpress printing machines

Text 4 Offset Presses

Text 5 Printing Presses for Packaging

Unit 6 Equipment and Machinery for Flat-bed Screen Printing

Unit 8 Printing units design

Text 1 Sheet-fed Printing Presses

Text 2 Web-fed Printing Presses

Text 3 Printing Unit Design on Web Presses

Unit 4 Printing Unit Configurations on Web Presses

Text 5 Gravure Printing in the Packaging

Text 6 Gravure Cylinder Manufacture

Unit 1 Printing processes

Text 1 Basic printing techniques

There are certain principles in printing that apply regardless of the particular process that is being used. It is important, for instance, to use the right size of press for the job. Conversely, the size of the job should in general be tailored to the machine being used for printing.

The main printing processes can be defined according to the physical characteristics of the printing surfaces used. Letterpress is a 'relief process, where the image to be printed is raised above the background; this raised surface is inked by rollers and then pressed against the paper to make the impression. Lithography is 'planographic', with a flat printing surface: the image area is chemically treated so that it accepts ink and rejects water, while the non-image area is treated to accept water and reject ink. Gravure is an 'intaglio' process, with the printing image recessed into the plate and filled with liquid ink; the non-image area is wiped free of ink, so that ink is deposited on the paper only from the recessed wells.

An operation that applies to all printing processes is make-ready' — that is, all the operations that take place prior to the first good copies being produced on a press. Most modern printing techniques therefore aim to reduce the time and expense involved in make-ready.

Most printing processes require the paper to be either sheet-fed or web-fed.

In sheet-fed printing the paper, which is made in the form of reels (large rolls), is cut into sheets of a suitable size for the press being used. The 'feeder' section of the press picks up the sheets, usually with a combination of metal fingers and vacuum suckers, and feeds them through to be printed. The sheets then pass on to the delivery end of the press, still as flat sheets — folding or other finishing processes are a separate operation requiring other machinery.

With web-fed (also known as reel-fed) printing, the paper is supplied to the machine in the form of reels. The front end of the press has a reelstand, which holds the paper as it is unwound and fed through the press. The actual method of printing is the same as with a sheet-fed press, but printing can take place at much higher speeds because the machine is not slowed down by having to pick up and put down each sheet before printing the next. Most web presses also incorporate some form of finishing facility after printing. Usually this is folding, but it can also include various types of gluing, stitching and perforating to give special products for direct-mail and other purposes; here the folding section of the machine may have added equipment for gluing and perforating.

The advantages of web-fed printing are speed. Web-fed presses therefore lend themselves to long runs. The disadvantages is that the web-fed presses involve a very high initial outlay, need more time before they are ready to start printing and mostly produce only items of a fixed length.

Exercises:

I. Read the following sentences and discuss whether they are true or false. If they are false, correct them.

1. Small offset press is suitable to print 100.000 copies of a magazine.

2. The size of the page should correspond to the plate size.

3. In the letterpress process the image to be printed is raised above the background.

4. Lithography stands for an “intaglio” process.

5. Gravure is a process with a flat printing surface.

6. There are four basic methods of printing.

7. With web-fed printing, the paper is supplied to the machine in the form of sheets.

8. Most presses incorporate folding, gluing, stitching and perforating after printing.

9. The printing presses have auxiliary devices for finishing processes.

10. Web-fed printing is slower than sheet-fed.