Plasma Cured Inkjet Printing System

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Solution Overview

Problem

Inkjet printing technologies face challenges in achieving durable prints due to the high cost of UV curing systems and the instability of photoinitiators in aqueous inks, which can lead to premature polymerization when exposed to UV light.

Innovation Solution

The use of a plasma generator, specifically a surface barrier discharge plasma generator, to cure inkjet inks by generating free radicals that polymerize or crosslink curable binders, eliminating the need for photoinitiators and reducing costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a UV curing lamp is incorporated to cure inkjet inks, then the durability of printed images is improved, but the cost of the printing system increases significantly

Engineering Contradiction:
Improvedurability of printed imagesVSAvoidcost of printing system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates the UV curing lamp from the printing system by using an alternative plasma-based curing mechanism. The ink formulation includes a curable component that can be cured by plasma treatment instead of UV radiation, removing the need for expensive UV curing hardware while maintaining image durability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the curing parameter from UV radiation to plasma treatment. By modifying the curing mechanism from optical (UV) to plasma-based, the system achieves durable prints without requiring UV lamps, thereby reducing system cost and complexity.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If photoinitiators are included in aqueous inkjet inks, then UV curing capability is improved, but the stability of the ink decreases due to premature polymerization

Engineering Contradiction:
ImproveUV curing capabilityVSAvoidstability of ink
Core Design Contradiction:
Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The patent removes photoinitiators from the ink formulation entirely, replacing them with a plasma-curable curable component. This eliminates the risk of premature polymerization associated with photoinitiators while maintaining the ability to cure the ink through plasma treatment.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces plasma as an intermediary curing mechanism between the ink application and final curing. Instead of using photoinitiators that directly trigger polymerization upon UV exposure, the plasma acts as a mediator that activates the curable component only when exposed to plasma treatment, preventing premature reactions.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of manufacture

If photoinitiators and curable components are combined in the ink, then curing functionality is improved, but the risk of premature polymerization increases when exposed to UV light

Engineering Contradiction:
Improvecuring functionalityVSAvoidpremature polymerization
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent extracts the problematic combination of photoinitiators and curable components by using a plasma-curable alternative. The curable component is formulated to remain stable in the ink until exposed to plasma treatment, eliminating the harmful interaction between photoinitiators and UV light that causes premature polymerization.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent converts the potential harm of UV light exposure (which causes premature polymerization) into a benefit by using plasma treatment as the curing mechanism. Plasma treatment provides the necessary energy to cure the curable component without causing premature reactions, turning a potential problem into a controlled curing process.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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 method enhances the durability of printed images without the need for UV radiation, stabilizing the ink and increasing shelf-life, while providing a cost-effective solution for curing inkjet inks, as demonstrated by improved resistance to smudging and finger rubbing tests.

Implementation Method 1

a plasma generator to plasma treat the printed image

Methodology Applied
Scientific EffectPlasma: Plasma

Implementation Method 2

The plasma generator can generate free radicals, which interact with the curable binder to begin the polymerization or crosslinking process

Methodology Applied
Scientific EffectFree radical polymerization: Photopolymerisation

Data Source

PatentEP3414097B1Printing systems
Publication Date: 2022.09.07 HEWLETT PACKARD DEVELOPMENT COMPANY LP
  • EP3414097B1 patent drawingFigure 1A~1B
  • EP3414097B1 patent drawingFigure 2A~2B
  • EP3414097B1 patent drawingFigure 3~4

AI summary

The present disclosure is drawn to printing systems. In one example, a printing system can include an inkjet print head and a plasma generator. The inkjet print head can be used to form a printed image on a media substrate. The plasma generator can be positioned with respect to the inkjet print head to treat the printed image after application to the media substrate.