Inkjet Printing Device with Partial Curing for Flexible Substrates

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Solution Overview

Problem

Existing printing devices are not adapted for printing with curable ink on flexible substrates with smooth surfaces, leading to issues with ink curing and substrate handling, particularly in digital printing processes where multiple colors are applied sequentially, and the length of the transport belt complicates control and increases costs.

Innovation Solution

The device incorporates two ink units and two curing units that partially cure the ink, allowing for the production of semi-finished laminated floor products, with a conveyor system that supports the substrate by gravity, maintaining alignment and reducing mechanical tension, and a control unit that manages the curing process to achieve optimal adhesion and cohesion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a long transport belt is used to convey substrates through multiple printing and curing units, then complete curing of all color layers is achieved, but the device complexity and control difficulty increase significantly

Engineering Contradiction:
Improvecuring completenessVSAvoidconveyor control complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The curing process is segmented into multiple independent curing units, each associated with a specific printing unit. Each curing unit only cures the ink from its associated printing unit partially, rather than using one long conveyor to cure all layers completely. This segmentation reduces the required conveyor length and simplifies control while ensuring proper curing at each stage.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Each curing unit applies partial curing action to the ink layer, curing only to the extent needed for that specific color layer before the next printing stage. This partial curing approach allows the process to proceed through multiple stages without requiring complete curing at each step, reducing the overall conveyor length needed while maintaining print quality.

Inventive Principle:
Principle #16Partial or excessive action

2Manufacturing precision

If multiple color inks are applied one after the other with complete curing between layers, then adhesion between layers is improved, but production time and conveyor length increase

Engineering Contradiction:
Improvelayer adhesionVSAvoidproduction cycle time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

Instead of applying excessive curing action to fully cure each layer before the next printing step, the system applies partial curing action that is sufficient for maintaining layer adhesion but not complete curing. This allows the next color layer to be printed on partially cured ink, reducing the time and conveyor length required while still achieving adequate adhesion between layers.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The printing and curing process continues without interruption through multiple stages. While one layer is being cured partially, the system immediately proceeds to print the next color layer without waiting for complete curing or idle periods. This continuous operation reduces production cycle time while maintaining layer adhesion through the partial curing approach.

Inventive Principle:
Principle #20Continuity of useful action

3Device complexity

If the conveyor belt length is reduced to lower costs, then device complexity decreases, but controlling substrate alignment and tension becomes more difficult

Engineering Contradiction:
Improveconveyor system simplicityVSAvoidsubstrate alignment
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The conveyor system is segmented into multiple shorter conveyor sections, each associated with a specific printing and curing unit. Each section is independently controlled and optimized for its specific function, making alignment and tension control more manageable compared to a single long conveyor. This segmentation maintains manufacturing precision while reducing overall system complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The conveyor system is designed to maintain consistent tension and alignment conditions across all printing and curing stations. By ensuring equipotential conditions (uniform tension, speed, and positioning) at each stage, the system achieves proper substrate alignment without requiring an excessively long conveyor belt, thus simplifying the overall system while maintaining precision.

Inventive Principle:
Principle #12Equipotentiality

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 solution enhances print quality by ensuring partial curing of inks between color layers, allowing for efficient production of laminated floor coverings while minimizing the length and complexity of the conveyor system, thus reducing costs and improving substrate handling.

Implementation Method 1

Each of the curing units (30, 32, 34, 36) being adapted to cure the ink printed by the inkjet printing unit (20, 22, 24, 26) associated with the curing unit

Methodology Applied
Scientific EffectUV curing: Photopolymerisation

Data Source

PatentEP3406453B1Device for printing and corresponding method
Publication Date: 2022.09.07 TARKETT GDL
  • EP3406453B1 patent drawingFigure 1
  • EP3406453B1 patent drawingFigure 2~4

AI summary

This device (2) for printing on a surface (16) of a substrate (14) comprises first and second inkjet printing units, a supporting conveyor means (40). The inkjet printing units are arranged so as to be adapted to print, onto the surface of the substrate while the substrate is on the supporting conveyor means. The device (2) comprises a first curing unit (30) arranged downstream the first inkjet printing unit (20) and upstream the second inkjet printing unit (22). The first curing unit (30) is adapted to partially cure the ink printed by the first inkjet printing unit. The device comprises a second curing unit (32, 34, 36) arranged downstream the second inkjet printing unit (22, 24, 26) and adapted to partially cure the ink printed by the second inkjet printing unit. Application to devices for printing substrates for floor elements.