Flexographic CMYK Ink Layering for Clear Container Image Transfer

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Solution Overview

Problem

Existing flexographic printing methods face challenges in achieving high-quality images due to ink mixing and back-trapping issues when applying multiple layers of UV curable process colors, particularly with the CMYK color system, as conventional viscosity ranges are insufficient for effective wet trapping.

Innovation Solution

A method involving the sequential deposition of UV curable process color inks with non-overlapping viscosity ranges, applied in a specific order from darker to lighter colors, ensuring each layer is transferred and cured on a substrate while maintaining distinct viscosities to prevent mixing, using a flexographic transfer printing system with optimized components like anilox rolls and doctor chambers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If multiple layers of UV curable process color inks are applied sequentially using conventional flexographic printing methods, then complete color images can be formed, but ink mixing and back-trapping occur due to insufficient viscosity differentiation

Engineering Contradiction:
Improveimage qualityVSAvoidink mixing
Core Design Contradiction:
Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The invention changes the viscosity parameter of the inks by formulating UV curable process color inks with specifically controlled viscosity ranges. Each ink (cyan, magenta, yellow, black) is assigned a distinct viscosity range that does not overlap with others, preventing ink mixing during sequential application while maintaining complete color image formation

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention applies local quality by giving each ink layer a specific viscosity characteristic tailored to its color and position in the printing sequence. This localized viscosity differentiation ensures that each ink layer maintains its integrity without being affected by subsequent layers, eliminating back-trapping while allowing complete color buildup

Inventive Principle:
Principle #3Local quality

2Reliability

If inks with different viscosities are used to prevent mixing, then wet trapping can be achieved, but the viscosity range available for flexographic printing is insufficient for effective wet trapping of multiple CMYK colors

Engineering Contradiction:
Improvewet trappingVSAvoidviscosity range
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The invention expands the applicable viscosity range for flexographic printing by formulating UV curable inks with viscosities specifically optimized for this application. The viscosity ranges (cyan: 15-25 cP, magenta: 20-30 cP, yellow: 25-35 cP, black: 30-40 cP at 23°C) are tailored to ensure reliable wet trapping while maintaining compatibility with flexographic printing processes

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention uses composite material formulation by combining UV curable resins with pigments and viscosity modifiers in specific ratios to create inks with precisely controlled viscosity characteristics. This composite approach allows simultaneous achievement of appropriate viscosity, color strength, and wet trapping capability for each process color

Inventive Principle:
Principle #40Composite materials

3Quantity of substance

If sequential deposition of multiple ink layers is performed, then complete color images can be built up, but ink layers mix and lose color clarity

Engineering Contradiction:
Improvenumber of ink layersVSAvoidcolor mixing
Core Design Contradiction:
Quantity of substanceVSObject-generated harmful factors

Solution Approach 1:

The invention changes the viscosity parameter of each ink to create a hierarchical structure where each ink layer has a distinct flow resistance. This parameter differentiation allows four complete ink layers (CMYK) to be deposited sequentially without intermixing, maintaining color clarity while achieving full color image composition

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention applies preliminary anti-action by pre-formulating each ink with a viscosity that prevents it from being disrupted by subsequently applied inks. The viscosity gradient is established beforehand in the ink formulation stage, creating inherent protection against mixing before the printing process begins

Inventive Principle:
Principle #9Preliminary anti-action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach results in high-quality images with clear layer separation and reduced ink mixing, allowing for efficient application of multiple ink layers on containers, particularly cups, with improved opacity and color clarity.

Implementation Method 1

UV curing the UV curable process colour inks of the image on the container

Methodology Applied
Scientific EffectUV curing: Photopolymerisation

Data Source

PatentEP4277796B1Method for applying an image built up of multiple ink layers on a face of a container, ink set for said method and flexographic transfer printing system for said method
Publication Date: 2026.03.25 VAN DAM INT HLDG BV
  • EP4277796B1 patent drawingFigure 1A~1B
  • EP4277796B1 patent drawingFigure 1C
  • EP4277796B1 patent drawingFigure 2A~2B

AI summary

Method for applying an image built up of multiple ink layers on a face of a container A method for applying an image built up of multiple ink layers on a face of a container, in particular a cup, is provided. In the method, UV curable process colour inks are provided as primary colours of a CMYK colour system, the UV curable process colour inks having different viscosity in substantially non-overlapping viscosity ranges and the UV curable process colour inks are applied to the blanket in an order of decreasing viscosity. Also, several components of a flexographic transfer printing system which are compatible for use with the method are provided.