Sacrificial Coating for Inkjet Transfer Member

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Solution Overview

Problem

Indirect inkjet printers face challenges in achieving both good wet image quality and image transfer, as high surface energy materials promote ink spreading but hinder transfer, while low surface energy materials facilitate transfer but impede spreading, leading to issues like grainy images and streaks.

Innovation Solution

A sacrificial coating composition is applied to the intermediate transfer member, comprising a polymer, chain extender, hygroscopic plasticizer, and surfactant, which is partially dried to form a hydrophilic layer that enhances ink wetting and spreading while maintaining image transfer capabilities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a high surface energy material is used for the intermediate transfer member, then ink spreading and wetting is improved, but image transfer capability deteriorates

Engineering Contradiction:

Improvewet image qualityVSAvoidimage transfer capability

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The invention divides the intermediate transfer member surface into two distinct layers: a base layer made of low surface energy material (silicone, fluorosilicone, fluoropolymer, or hybrid material) that provides image transfer capability, and a sacrificial coating layer made of starch or starch derivative that provides high surface energy for ink spreading. This segmentation allows each layer to perform its specific function without compromising the other.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The sacrificial coating acts as an intermediary layer between the ink and the base intermediate transfer member. It temporarily modifies the surface properties during the printing process to enable proper ink spreading, then is removed after transfer to restore the original low surface energy properties for subsequent printing cycles.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If a low surface energy material is used for the intermediate transfer member, then image transfer capability is improved, but ink spreading and wetting deteriorates

Engineering Contradiction:

Improveimage transfer capabilityVSAvoidwet image quality

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention changes the surface energy parameter of the intermediate transfer member dynamically by applying a sacrificial coating. The base material maintains low surface energy for transfer, while the coating temporarily increases surface energy for ink spreading. After use, the coating is removed, restoring the original surface energy parameters.

Inventive Principle:

Principle #35Parameter changes

3Manufacturing precision

If a starch sacrificial coating is applied to improve ink spreading, then wet image quality is improved, but the coating must be removed after use adding process complexity

Engineering Contradiction:

Improvewet image qualityVSAvoidcoating application and removal process

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The sacrificial coating is designed to be discarded after a single use cycle. It is applied to the intermediate transfer member, performs its function of enabling ink spreading, and then is completely removed. The base intermediate transfer member is recovered and reused for the next printing cycle, eliminating the need for complex reusable coating systems.

Inventive Principle:

Principle #34Discarding and recovering

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 improves wet image quality and image transfer by creating a hydrophilic surface that allows ink to spread effectively and transfer efficiently, resulting in better print quality and robustness.

Implementation Method 1

the at least one chain extender comprises a species capable of linking linear chains or chain segments of the reactive elastomeric latex

Methodology Applied

Scientific EffectChemical Bonding: Chemical Bonding

Implementation Method 2

at least one surfactant

Methodology Applied

Scientific EffectSurfactant: Surfactant

Implementation Method 3

at least one hygroscopic plasticizer

Methodology Applied

Scientific EffectHygroscopic: Absorption (physical)

Data Source

PatentUS10675862B2Compositions and use of compositions in printing processes

Publication Date: 2020.06.09 GENESEE VALLEY INNOVATIONS LLC

AI summary

An aqueous sacrificial coating composition for an image transfer member in an aqueous ink imaging system is provided. The sacrificial coating composition may include at least one polymer, at least one selected from (i) at least one chain extender, or (ii) a reactive elastomeric latex, wherein the at least one chain extender comprises a species capable of linking linear chains or chain segments of the reactive elastomeric latex, at least one hygroscopic plasticizer, and at least one surfactant.