Single Pass Inkjet Printing Device with Intermediate UV Curing

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Solution Overview

Problem

High-speed single pass inkjet printing on non-absorbing surfaces with low surface energy faces challenges such as ink spreading issues, coalescence, bleeding, and gloss homogeneity, particularly due to the complex behavior of UV-curable inks, which existing methods struggle to address effectively without complex and costly surface treatments or multiple pass processes.

Innovation Solution

A single pass inkjet printing device with staggered nozzles and a radiation curing station that divides ink into portions, allowing for pin curing and final curing, enabling high-quality image printing without surface treatments, by jetting the first portion of ink and then partially curing it before jetting subsequent portions, thereby improving ink spreading and adhesion on non-absorbing surfaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If UV-curable ink is jetted onto a non-absorbing ink-receiver with low surface energy, then high-speed single pass printing is achieved, but poor ink spreading and adhesion control occur

Engineering Contradiction:
Improveprinting speedVSAvoidink spreading control
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The ink application process is divided into multiple jetting passes with intermediate curing steps. The first portion of ink is jetted and partially cured, then subsequent portions are jetted and cured, allowing controlled building up of ink layers without uncontrolled spreading on the low surface energy substrate

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The first portion of ink is jetted and partially cured before jetting the second portion. This preliminary curing action creates a stabilized base layer that prevents uncontrolled spreading and allows subsequent ink layers to adhere properly without compromising the high-speed single pass printing capability

Inventive Principle:
Principle #10Preliminary action

2Productivity

If multiple ink portions are jetted without intermediate curing, then high printing speed is maintained, but ink coalescence and bleeding occur

Engineering Contradiction:
Improveprinting speedVSAvoidimage quality
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The printing process uses periodic alternating actions of ink jetting and radiation curing. After jetting the first portion of ink, radiation is applied to partially cure it, then the second portion is jetted and cured. This periodic cycle prevents continuous wet ink contact that causes coalescence and bleeding while maintaining high printing speed through the single pass approach

Inventive Principle:
Principle #19Periodic action

3Manufacturing precision

If surface treatment equipment is incorporated to increase surface free energy, then ink spreading improves, but device complexity and cost increase

Engineering Contradiction:
Improveink spreadingVSAvoidprinter complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

Instead of modifying the substrate surface energy through additional equipment, the invention changes the process parameters by controlling the curing state of the ink. By adjusting the degree of curing (partial vs. full) and the timing of radiation application, optimal ink spreading and adhesion are achieved on the original low surface energy substrate without adding complex surface treatment equipment

Inventive Principle:
Principle #35Parameter changes

4Manufacturing precision

If first ink portion is partially cured before jetting second portion, then ink adhesion and spreading improve, but additional curing station requirements increase

Engineering Contradiction:
Improveink adhesionVSAvoidcuring station requirements
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The radiation curing station performs multiple functions: it partially cures the first ink portion, allows subsequent ink layers to be jetted and cured on top, and provides final complete curing of all ink layers. This multi-functionality achieves improved ink adhesion and controlled spreading without requiring separate dedicated curing stations for each function

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The curing operations are merged into a single curing station that handles both the intermediate partial curing of the first ink portion and the final complete curing of all ink layers. This consolidation reduces equipment complexity while maintaining the beneficial effects of staged curing for improved ink adhesion and spreading control

Inventive Principle:
Principle #5Merging (Combining)

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

The solution achieves high image quality with reduced visibility of lines or artefacts, improved ink spreading, and enhanced gloss homogeneity, extending the lifespan of print heads by masking nozzle failures and reducing cross-talk effects, while also reducing ink load and curing station requirements, leading to cost savings and increased system lifetime.

Implementation Method 1

a radiation curing station for curing the first ink when jetted on the surface by the first set of nozzles

Methodology Applied
Scientific EffectRadiation curing: Photopolymerisation

Data Source

PatentEP2633998B1Use of a single pass inkjet printing device
Publication Date: 2020.10.21 AGFA NV
  • EP2633998B1 patent drawingFigure 1~3
  • EP2633998B1 patent drawingFigure 4~5

AI summary

A method and an inkjet printing device (10) are disclosed for single pass printing on an ink-receiver (50) having a surface (51), the device including a plurality of sets of nozzles (15-18, 25-28) for jetting N inks on the surface (51), wherein N is larger than or equal to one, the N inks including a first ink, and wherein the plurality of sets of nozzles includes a first (15) and a second (25) set of nozzles for jetting the first ink; the device further including means for radiation curing (19, 41-43) the first ink when jetted on the surface by the first set of nozzles, wherein the means for radiation curing (19, 41-43) is positioned between the first set of nozzles (15) and the second set of nozzles (25).