3.1c Printing Proceses

• Direct - when the image is transferred directly from the cylinder to the paper
• Indirect - From the plate cylinder to the blanket cylinder then to the paper
• Offset Lithography

  1. A flexible printing plate is attached to a plate cylinder
  2. Rollers apply water to the blank section but is repelled by the emulsion on the image are
  3. Ink applied by other rollers is repelled by water but stays on the emulsion layer
  4. The plate cylinder rolls on a blanket cylinders which squeezes water away and picks up the ink
  5. The paper rolls between the impression and blanket cylinder
• Offset Lithography

  
• Advantages to Offset Lithography

  • Good resolution
  • Inexpensive
  • Fast
  • Print on range of papers
• Disadvantages of Offset Lithography

  • Can have colour variation
  • Paper can stretch
  • Can only be used on flat materials
• Flexography

  1. A printing plate is made from a flexible material and is attached to the plate cylinder
  2. Ink is picked up using a fountain roller which presses onto the anilox roller
  3. The anilox roller presses onto the painting cylender which transfers onto the paper
  4. This uses CMYK
• Flexography

  
• Advantages of Flexography

  • High speed
  • Fast drying
  • Different materials can be used
• Disadvantages of Flexography

  • Difficult for high detail
  • Inconsistent colour
  • High set up cost
• Offset vs Flex

  • Flex - straight to the material
  • Offset - Higher quality
  • Flex - Faster
• Gravure Printing

  1. An image is engraved into a copper plate
  2. The cylinder has small indents which controls the amount of ink
  3. The plate cylinder is turned through ink
  4. Doctor blade acts as a squigie
• Advantages of Gravure printing

  • Consistent colour
  • High speed
  • Widest printing press
  • Good results
• Disadvantages of Gravure printing

  • High costs
  • Only good for high printing runs
  • Dots are visable
• Gravure printing

  
• Screen printing

  1. Photo emulsion is applied to the mesh screen with a squeegee and then left to dry in a dark place
  2. A template is placed over the screen which is then exposed to light
  3. The photo emulsion that is exposed to light hardens leavening a negative
  4. The screen is then washed then placed over the material
  5. Ink is then placed on the screen and then spread with a squeegee