The five main types of printing are:

Transcription

1 The five main types of printing are: Relief- Letterpress, Block printing, Flexography (foil blocking) Planographic (flat plate printing)- Lithography & offset lithography Intaglio (etching) Gravure, Screen Printing Xenography (dry printing)- Photocopying, Laser printing, commercial digital printing Please note that while it is good to know what these are, not all are required for the AQA syllabus.

2 Advantages of offset lithography: Prints 4 colours onto flat materials It is a high quality process Very economical on medium to large production runs ,000 It is a fast process speeds of up to 50,000 presses per hour can be acheived on a web fed press! Disadvantages of offset lithography Less economic than rotogravure and flexography on high volume printing 1,000,000+ Less economic than digital printing on small to medium runs ,000(although quality is slightly higher) Limited to the type of materials it can print onto the surface must be flat. Litho would not be accurate enough for newspaper print.

3 The main application of gravure covers a wide range of commercial products. Gravure is especially suited to work in the four colour process on relatively cheap papers in quantities over 250,000. The reason being the expense of the original printing plates which can each run into thousands of pounds. Example applications include magazines mail-order catalogues Board packaging products such as folding box cartons for food and cigarette industries, also printed video cases. Flexible packaging such as printed cellophane and polythene used in food wrapping, display and production.

4 Advantages of Gravure: It can be used for the highest quality reproductions It uses lower grade, lighter paper than lithography High speed usually ,000 prints per hour Automatic registration. Disadvantages of gravure Initial cost of rotogravure plates extremely high therefore it is only economic for very high print runs Colour correction is difficult

5 Silk Screen Printing Screen Printing is unlike any other process as it uses a stencil through which ink is pushed. The process involves forcing ink through a fine mesh (screen) which helps to spread the ink evenly. Its easy to use, versatile and requires low capital investment. Relatively cheap on short and medium print runs automated presses which can print, varnish or gum up to 6000 per hour. Most importantly it can print onto curved and uneven surfaces

6 For printing, and image is separated into its colours Cyan, Magenta, Yellow and Black (CMYK). Each colour is printed over the other as the paper (or substrate) moves through the presses. Each colour has its own press. Full Colour Printing Cyan magenta yellow black For the original go to micro.magnet.fsu.edu/.../primarycolors/ colorseparation/

7 Quality Control The two main quality checks are: Registration Colour Density Registration can be checked by either eye or automatically and are used to check that the 4 processes are aligned properly on the substrate. Images out of alignment can appear blurred. Registration marks at about 10X magnification Colour density is checked using a Densitometer, which is a hand held device that measures the density of colour. The densitometer is held over the colour bar (one colour for each of the process colours and greyscale. A colour density bar

8 Binding Once printed the next stage is the binding of the product. The bindery is where the printed product is completed. The huge rolls of now-printed paper are cut and put together so that pages fall in the correct order. Pages are also bound together by, staples or glue, in this step of the process. A machine called a stitcher takes the folded printed paper (called press signatures) and collates them together. The final components in the stitcher machine are the knives which trim the paper to its final delivered size. A sticher machine Paper being cropped manually

9 Cutting and Folding (creasing) Most cartons (packages, boxes) require cut outs and creases in order for them to be assembled. The machine tool used on modern presses is the die cutter.