Click the button below and listen to answer the questions. Then check your answers with the correct answers given in the comment box!
NeoTips for diagram and labbeling
When you do a diagram, remember that the stages and the answers are in the same order. Read more and more diagrams and this type of question becomes easy.
Complete the diagram below.
Write NO MORE THAN TWO WORDS for each answer.
Complete the sentences below.
Write NO MORE THAN THREE WORDS for each answer.
6 The main advantage of rotogravure is the large ____________which is transferred.
7. ___________ and photographs reproduce well in the rotogravure process.
8 Sunday newspapers often contain___________ produced by rotogravure.
9 Apart from paper, floor coverings and___________can be printed by rotogravure.
10 The main problem with rotogravure is that the___________ to the naked eye.
Lecturer: As I’ve made clear in earlier lectures, many different solutions have been proposed to the basic technological problem of getting meaningful marks onto paper. In other words, several different forms of printing have developed over the years, many of which are still in use today for different purposes. This week, I’d like to discuss the rotogravure process. This is one of the most widely-used printing processes, and after describing how the process works, I’ll be describing some of its industrial uses and the advantages and disadvantages of this form of printing.
As the name implies, rotogravure is a form of printing in which large cylindrical pieces of metal rotate, while the paper to be printed passes between them. The paper is held in place against the printing surface by_ the impression roller. The weight of this roller is one of the factors that affect how much ink is actually transferred to the paper. Remember that this roller does not directly transfer ink onto the paper. The side in contact with the impression roller remains blank, and it’s the other side of the paper which is actually-the printed side.
The impression roller presses the paper against the ink-bearing roller, generally known as the gravure cylinder. This roller is etched or engraved using either a laser or a diamond-tipped etching machine. This creates a large number of tiny holes in the surface of the roller which hold the ink. The depth and size of these holes determines how much ink is picked up from the ink fountain which the whole printing assembly rests in. How much ink is picked up in turn determines the density of the image produced. As it rotates, the lower roller picks up more ink on its surface than is required, and this needs to be removed before contact with the paper. A flat edge, called the doctor blade, scrapes against the surface and removes all ink which is not in one of the holes on the surface of the lower roller. This should lead to a clean image.
Now that we understand a little of the mechanics of rotogravure printing, I’d like to look at it in the wider context of the printing industry and discuss the main uses. One of the main advantages of the rotogravure process is that the amount of ink which can be transferred to the paper is high compared to other printing methods. This means that a broad density range can be produced. In other words, with rotogravure it’s possible to produce many different light and dark shades, making it particularly suitable for reproducing photographs and fine art. For shorter print runs, some other processes may give a finer image, but rotogravure is ideal for jobs that involve printing, for example, a million magazines.
One common place where you’ll see printed matter that has been produced by rotogravure is in the advertising material that is often inserted into Sunday newspapers.
Of course, it’s not just paper that can be printed by rotogravure. It’s a very flexible process, since the rollers used can be made to any size required. Whether it’s consumer packaging or large rolls of floor covering that need to be printed, rotogravure is a relatively cheap, quick method that is used in a variety of industries. This isn’t to say that rotogravure is without its disadvantages. Probably the main drawback is the fact that with large areas of colour the dots are visible, even without using any kind of magnifying aid. Now, does anyone have any questions about the rotogravure process?