CPT Printing & Decoration Technologies 2 — Questions and Answers
Question 1: Which printing process uses a raised image surface to transfer ink directly onto the substrate?
- Gravure
- Flexography (Correct answer)
- Offset lithography
- Screen printing
Correct answer: Flexography
Flexography uses raised relief plates where ink is applied to the raised image areas and transferred to the substrate.
Question 2: In gravure printing, what determines the volume of ink deposited on the substrate?
- Plate pressure
- Cell depth and size (Correct answer)
- Anilox roller line screen
- Impression cylinder speed
Correct answer: Cell depth and size
In gravure, ink is held in engraved cells; cell depth and size control how much ink transfers to the substrate.
Question 3: What is the primary function of a doctor blade in gravure and flexographic printing?
- Control ink viscosity
- Remove excess ink from non-image areas (Correct answer)
- Maintain substrate tension
- Regulate dryer temperature
Correct answer: Remove excess ink from non-image areas
The doctor blade wipes excess ink off the gravure cylinder or anilox roller surface, leaving ink only in the recessed cells.
Question 4: Which ink drying mechanism is most common in UV-curable flexographic inks?
- Evaporation of solvent
- Absorption into substrate
- Photopolymerization triggered by UV light (Correct answer)
- Oxidative polymerization
Correct answer: Photopolymerization triggered by UV light
UV-curable inks contain photoinitiators that trigger polymerization when exposed to ultraviolet light, instantly hardening the ink.
Question 5: Hot stamping foil decoration transfers metallic or holographic layers using:
- Solvent adhesion
- Heat and pressure (Correct answer)
- Electrostatic attraction
- UV bonding
Correct answer: Heat and pressure
Hot stamping applies a heated die under pressure to release the foil layer from its carrier film onto the substrate.
Question 6: Which color model is standard for specifying process colors in packaging printing?
- RGB
- HSB
- CMYK (Correct answer)
- LAB only
Correct answer: CMYK
CMYK (Cyan, Magenta, Yellow, Key/Black) is the standard four-color process model used in commercial packaging printing.
Question 7: Ink trapping in multicolor printing refers to:
- Ink bleeding into the substrate fibers
- The ability of a wet ink layer to accept a subsequent ink layer (Correct answer)
- Color gamut expansion using extra inks
- Preventing ink migration through barrier coatings
Correct answer: The ability of a wet ink layer to accept a subsequent ink layer
Trapping is the capacity of a freshly printed ink film to accept and hold the next ink printed over it without repulsion.
CPT Printing & Decoration Technologies 2
Which printing process uses a raised image surface to transfer ink directly onto the substrate?