Paper Printing and Finishing Techniques

Question 1

What is the substrate?

Answer 1

the material on to which the prink ink is applied, such as paper or boards

Question 2

What items use screen printing?

Answer 2

posters, display boards and textile t-shirts

Question 3

Why does screen printing have minimal set-up costs?

Answer 3

due to the basic screens and printing inks

Question 4

How does screen printing work?

Answer 4

The substrate to be printed sits on the screen print machine base and the upper section secures the screen. The image to be printed is created on a screen (or a stencil), which is a mesh held by a frame. The screen has open areas for the ink to pass through. A different screen is required for each colour. This can increase the time taken to produce the print as well as the overall production cost per item. The screen is placed over the substrate on the machine bed. The pigmented printing ink is placed on the screen. A squeegee (a flexible polymer blade, held in a rigid handle) is then used to force the ink to flow through the mesh onto the substrate. Once ach colour is complete, the ink dries or cures to complete the print.

Question 5

Does screen printing print one or multiple colours at a time?

Answer 5

One colour

Question 6

Which printing processes uses a four-colour process?

Answer 6

flexography
offset lithography
digital printing

Question 7

What are the four colours that are used in the four-colour process of printing?

Answer 7

cyan
magenta
yellow
black

Question 8

How do you ensure an accurate and non-blurry print in flexographic printing?

Answer 8

The colours must line up precisely with each other. If one colour is slightly out of position, the printed image will appear blurred. In colour printing, a registration system is used to ensure the final image is consistent and of high quality.

Question 9

How does the registration system work with flexographic printing?

Answer 9

The registration mark is a set of precision marks on the final substrate, outside the print area, which is used as a quality control (QC) check to ensure all four colours have printed in the correct place. These registration marks are often seen at the side of printed newspapers as a bar of CMYK colours.

Question 10

Where can you find the registration marks from flexographic printing?

Answer 10

the sides of newspapers

Question 11

What is the least expensive printing process and why?

Answer 11

Flexographic printing is the least expensive of the printing processes due to the simple operation and use of fast-drying water-based inks.

Question 12

When is flexographic printing used?

Answer 12

newspapers
comics
catalogues
folding packaging cartons
labels
carrier bags
wallpaper

Question 13

What type of print runs does flexographic printing use and why?

Answer 13

As flexographic printing uses rolls of substrate rather than sheets, this allows large continuous print runs to be completed with ease.

Question 14

What is the process of flexographic printing?

Answer 14

1. it uses flexible printing plates wrapped around rotating cylinders on a web press.
2. Water-based or UV curable ink is fed from the first ink roller to the anilox roller.
3. The anilox roller makes the ink a uniform thickness and transfers the ink to the plate cylinder.
4. The substrate moves between the plate cylinder and the impression cylinder.
5. The impression cylinder applies pressure to the plate cylinder to transfer the image on to the substrate.
6. The web, which by now has been printed, is fed into the overhead dryer so that the ink is dry before it goes to the next print unit.

Question 15

What are the advantages of flexographic printing?

Answer 15

High print speed
Ideally suitable for long runs
Prints on a wide variety of substrate materials, both porous and non-porous.
Low cost of equipment and consumables
Low maintenance

Question 16

What are the disadvantages of flexographic printing?

Answer 16

The cost of the printing plates is relatively high, but they last for millions of print runs.
Takes a large amount of substrate to set up the job, excess material may be wasted.
Time consuming to change for any alterations to the print content.

Question 17

What kinds of printing processes is offset lithographic printing suitable for?

Answer 17

one colour (single roller)
five colours (CMYK plus can additional metallic colour on a five-roller machine)
ten-feature machine (CMYK, metallic, varnishing, spot varnishing and duplex on a ten-roller machine)

Question 18

What length of print runs does offset lithographic printing use?

Answer 18

medium and long print runs

Question 19

What products are printed using offset lithographic printing?

Answer 19

books
business forms and documentation
magazines
posters
packaging

Question 20

What principle is offset lithographic printing based on and how does this work?

Answer 20

Lithographic printing is based on the principle that oil and water do not mix. Lithographic plates are chemically treated to make the image area oleophilic (absorbs oils easily) and therefore receptive to oil-based printing inks. The non-image area is treated to be hydrophilic (absorbs water easily).

Question 21

What is the process of offset lithographic printing?

Answer 21

1. During printing, fountain (dampening) solution, which consists primarily of water, applied in a thin layer to the printing plate cylinder and is attracted to the hydrophilic non-image areas of the printing plate.
2. Ink is then applied to the plate and is attracted to the oleophilic image areas.
3. Since ink and water essentially do not mix, the fountain solution prevents ink from entering the non-image areas of the plate.
4. Printing substrate is either sheet-fed or web roll-fed into the printing machinery.
5. Printing plates are produced by a computer to plate (CTP) process via a laser which etches the image onto the plate. The plates are then attached to the machine and dampened by a damping roller.
6. The ink is applied to the printing plate. The plate cylinder rotates onto a blanket roller which becomes coated with ink. As the substrate is fed through, the image on the blanket is transferred to the substrate to produce the printed product.

Question 22

What are the advantages of lithographic printing?

Answer 22

Consistently high image quality
Suited to higher volume print runs of 1000 or more
Quick and easy production of printing plates
Long life of printing plates because they only come into contact with the printing blanket, which is softer and less abrasive than the substrate.

Question 23

What are the disadvantages of lithographic printing?

Answer 23

Expensive setup and running cost for small quantities
Only suitable for porous substrate materials

Question 24

Why is digital printing so popular?

Answer 24

its speed and efficiency

Question 25

What types of images do digital printers produce?

Answer 25

full colour, highly detailed print runs with the option of different designs on each page, both front and reverse sides.

Question 26

How do digital printers apply ink?

Answer 26

Similar to laser printers, where the ink sits on top of the paper and is allowed to dry or be laminated.

Question 27

What are some products that are printed using digital printers?

Answer 27

promotional materials such as business flyers and business cards

Question 28

Why is the use of digital printing ideal for mass customisation?

Answer 28

Due to the fast drying inks similar to those used in flexography