Questions about the text on page 38-39

1.Why can digital print be a good solution for a company?

2.How many percent of digitally produced products will be expected in 2010?

3.Will companies prefer extremal printing companies or will they print their products in-house in the future?

4.What improvements occur with the new digital printing machines?

5.What is the essential tool to use the full potential of digital printing machines?

6.Name some problems of printing companies in Europe which use digital printing machines.

7.Why don’t the USA have problems like these?

8.Is it profitable for companies to print the bulk of their products in offset when they also have a digital printing machine?

9.Why do individualizated digital prints have a higher response rate than standard offset products?

 

 

Digital printing: yes or no?

The employees ofMasterPrint

are arguing about digital printing. Can you help them to sort out the pros and cons

If MasterPrint wants to survive on the market, it is essential to buy a digital printing machine. Barbara Brown

It is faster than producing plates in the conventional way. Anita Jones

Products can be printed in a very short time. Bill Smith

The ink for digital printing is very expensive. Thomas Hiller

It is not necessary to be a qualified printer in order to handle a digital printing machine. Barbara Brown

We don’t know where the Return on investment is. Michael Sharpe

pros cons

It would be expensive for Mr Thomas to employ one more person. Arnold Jacobs

 

 

Someone has to be responsible for the customers database. Ethan Wilburg

There are nearly no register differences compared with offset printing. Thomas Hiller

Products with small print run can be printed more profitable than in offset. John Thomas

 

Liza has so far learned a lot about digital printing. Therefore she knows that it is possible to print different texts or photos in a single sheet pass. Now she wants to find out how it works. She is searching the Internet for more information and finds a useful diagram.

 

 

The principle of electrophotography

 

This is how most digital printing machines work. Look at the diagram below.

 

 

Based on: Kipphan, Handbook of Print Media, Springer 2001, ISBN 3-540-67326-1

 

copy charge toner light fuser unit paper

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Fill in the missing words

Copy the text into your notebook and fill

in the missing words from the yellow box.

 

The printed page is created by converting data into ____ which then erases charges on a charged, photosensitive rotating drum, thus reproducing information as an electrostatic pattern on the drum. The light source is a laser beam.

In the next step of the process, the drum comes in contact with a charged colour powder (____) and a pattern develops when the powder is attracted to the drum wherever a ______ remains. In the following step the developed pattern is transferred to ______ with the help of a strong electrostatic field. The drum must then be discharged, cleaned and recharged before it is ready for the next ____. At the same time the paper passes through a ____ where the toner is bonded to the paper fibers with the help of pressure and heat.

Liza looks at a printing plate through a magnifier. She notices that the screens of the products are different from each other. Kevin tells her about the AM and FM screening methods.

Screening methods

 

You can simulate continuous tones with screening in a number of ways.

Amplitude Modulation. In so-called amplitude-modulated screening (autotypical screening, periodic screening), the individual dots are spaced the same distance apart, but have different diameters (or different areas, depending on the dot shape). This halftone process, along with its distinct susceptibility to moire, is the more conventional one.

Frequency Modulation. In the case of frequency-modulated screening, the individual dots have the same diameter but are different distances apart (non-periodic screening). When using the frequency modulation screening process to convert continuous tones of the original into a quantity of dots in a so-called screen cell, the dot spacing must be specified for a known dot size. This can be done according to various algorithms. Usually the distances for a certain tone value differ from individual dot to individual dot (which would lead to susceptibility to moire patterns), but are distributed randomly. For this reason, frequency-modulated screening is also referred to as random or stochastic screening.

The graphic illustrates both screening processes, amplitude-modulated and frequency-modulated. The single-colour image shows that, when using identical dots of the smallest possible size, FM screening produces better reproduction of detail in printing than AM screening; it must also be possible to repeatedly reproduce each of the small dots in print. At multi-colour works one can clearly see that the FM screening produces a higher resolution and that its stochastic, random screening prevents rosettes.

Hybrid Screening. There are also hybrid techniques for screening continuous-tone originals: both AM and FM screening are used, depending on the image. A possible algorithm is based on the approach of using FM screening for very light and very dark tones and AM screening for the remaining tone value range.

 

Based on: Kipphan, Handbook of Print Media, Springer 2001, ISBN 3-540-67326-1

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