Transmissive Web UV Curing for Radiation-Curable Ink Leveling

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Solution Overview

Problem

Radiation-curable inks with a 'mayonnaise' consistency at room temperature pose challenges in ink-jet printing as they lack cohesive strength, leading to uneven gloss and incomplete image transfer due to phase change upon hitting the substrate, making conventional flattening methods ineffective.

Innovation Solution

A printing system that applies UV-curable ink directly to a substrate using a transmissive web with applied pressure and radiant energy, ensuring uniform curing and efficient ink adhesion, utilizing a web with low surface energy and hydrophobic properties to prevent ink offset during curing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If radiation-curable ink is applied directly to substrate without image receptor, then device complexity is reduced, but ink leveling and uniformity become difficult due to mayonnaise consistency

Engineering Contradiction:

Improveprinting system complexityVSAvoidink layer uniformity

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

A transmissive web is introduced as an intermediary carrier between the inkjet printhead and substrate. The web receives the ink deposit, applies pressure through pressure-sensitive rollers to level the ink, and then transfers the leveled ink to the substrate while allowing UV radiation to pass through for curing.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Manufacturing precision

If conventional flattening methods are used on mayonnaise-consistency ink, then ink leveling is attempted, but ink cohesive strength is insufficient causing image splitting and loss

Engineering Contradiction:

Improveink layer flatnessVSAvoidink cohesive strength

Core Design Contradiction:

Manufacturing precisionVSStrength

Solution Approach 1:

Pressure is applied to level the ink layer before the ink has been deposited onto the final substrate, while the ink is still on the transmissive web. This preliminary leveling action occurs when the ink is more manageable, preventing subsequent splitting during transfer and curing.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The transmissive web acts as a mediator that supports the ink layer during the leveling process, providing a stable platform that prevents ink splitting. The web's surface properties allow the ink to maintain integrity while being pressed flat, then transfer the leveled ink to the substrate without loss.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Manufacturing precision

If pressure is applied to flatten ink layer, then uniform thickness is achieved, but ink may offset to flattening device due to low surface energy requirements

Engineering Contradiction:

Improveink layer thickness consistencyVSAvoidink offset to flattening device

Core Design Contradiction:

Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The transmissive web serves as an intermediary that receives the ink deposit and allows pressure application for leveling. After leveling, the web transfers the ink to the substrate through controlled contact, minimizing offset to external flattening devices while maintaining surface energy compatibility.

Inventive Principle:

Principle #24Intermediary (Mediator)

4Ease of operation

If ink is heated for jetting then directly fired onto substrate, then ink becomes liquid for jetting, but phase change back to viscous reduces penetration into porous media

Engineering Contradiction:

Improveink jetting capabilityVSAvoidink penetration into substrate

Core Design Contradiction:

Ease of operationVSManufacturing precision

Solution Approach 1:

The transmissive web acts as an intermediary that receives the heated liquid ink from the printhead. The web allows the ink to cool and regain viscous consistency while maintaining proper adhesion, then transfers the ink to the substrate. This controlled environment on the web prevents premature phase change that would reduce penetration, while still enabling effective jetting.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 system achieves uniform ink curing and efficient ink transfer, maintaining image integrity and ensuring consistent layer thickness, addressing the issues of cohesive strength and phase change in radiation-curable inks.

Implementation Method 1

a web, the web being substantially transmissive of radiant energy

Methodology Applied

Scientific EffectTransmissivity: Absorption (EM radiation)

Implementation Method 2

applying pressure of a predetermined magnitude to the web and the substrate

Methodology Applied

Scientific EffectPressure: Pressure Increase

Implementation Method 3

photoinitiators in the ink are bombarded with UV radiation and the incident flux converts the monomers present in the ink into a cross linked polymer matrix

Methodology Applied

Scientific EffectPhotopolymerization: Photopolymerisation

Implementation Method 4

utilizing a web with low surface energy and hydrophobic properties to prevent ink offset during curing

Methodology Applied

Scientific EffectHydrophobicity: Hydrophobe

Data Source

PatentUS8323438B2Method for fixing a radiation-curable gel-ink image on a substrate

Publication Date: 2012.12.04 XEROX CORP

AI summary

An apparatus fixes ink on a substrate, such as in ink-jet printing. A leveling member is positioned to contact an ink-bearing side of the substrate at a nip. A radiation source is positioned to direct radiation to the ink-bearing side of the substrate at the nip, the radiation suitable for curing the ink on the substrate.