Thermal Image Receiver Elements with Release Agents
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Solution Overview
Problem
Aqueous-coated thermal image receiver elements face challenges in high humidity environments, where they tend to stick together with thermal donor elements and exhibit inadequate dye density and instability when exposed to water, leading to inconsistent print quality.
Innovation Solution
A thermal image receiver element with a dry image receiving layer comprising a water-dispersible acrylic polymer and a polyester binder matrix, including a water-dispersible release agent, which provides improved resistance to humidity changes and reduced sticking, ensuring consistent dye density and print quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If aqueous coating formulations are used to prepare the dye image receiving layer, then environmental hazards and manufacturing costs are reduced, but the layer exhibits sticking problems in high humidity environments and high speed printing
Solution Approach 1:
A release agent layer is introduced as an intermediary between the aqueous coating formulation and the thermal donor element. This release agent prevents direct adhesion between the aqueous-based receiving layer and the donor element, eliminating sticking problems while maintaining the environmental benefits of aqueous coating. The release agent acts as a mediating substance that enables smooth separation during high speed printing.
Solution Approach 2:
The invention modifies the surface properties of the aqueous coating by controlling the glass transition temperature (Tg) of the polymer binder and adjusting the formulation parameters. By optimizing the Tg range and using specific polymer compositions, the coating maintains appropriate adhesion during printing while preventing excessive sticking in high humidity conditions, thus resolving the reliability issue.
2Device complexity
If aqueous coating formulations are used to prepare the dye image receiving layer, then manufacturing complexity is reduced, but dye density and print quality consistency are insufficient
Solution Approach 1:
The invention uses composite polymer formulations combining water-dispersible polymers with specific Tg ranges and complementary polymer blends. This composite approach allows the aqueous coating to achieve consistent dye density and print quality while maintaining simple manufacturing processes. The synergistic interaction between different polymer components ensures uniform dye reception and transfer.
3Object-affected harmful factors
If aqueous coating formulations are used to prepare the dye image receiving layer, then environmental hazards are reduced, but the layer falls apart when contacted with water
Solution Approach 1:
The invention carefully selects and optimizes the glass transition temperature (Tg) range of the polymer binder and adjusts the crosslinking density to achieve the right balance between water dispersibility and water resistance. By controlling these parameters, the coating maintains structural integrity when contacted with water while preserving the environmental benefits of aqueous-based formulation.
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 combination of polymers and release agents in the image receiving layer enhances the thermal image receiver elements' resistance to humidity changes, reducing sticking issues and maintaining consistent dye density, thereby improving the reliability and quality of thermal dye transfer images.
Implementation Method 1
the combination of polymers and release agents in the image receiving layer enhances the thermal image receiver elements' resistance to humidity changes
Implementation Method 2
a water-dispersible release agent, which provides improved resistance to humidity changes and reduced sticking
Implementation Method 3
A line-type thermal printing head is used to apply heat from the back of the dye-donor sheet
Implementation Method 4
The thermal printing head has many heating elements and is heated sequentially in response to one of the cyan, magenta or yellow signals
Data Source
AI summary
A thermal image receiver element dry image receiving layer has a Tg of at least 25° C. and is the outermost layer. The dry image receiving layer has a dry thickness of at least 0.5 μm and up to and including 5 μm. It comprises a water-dispersible release agent and a polymer binder matrix that consists essentially of: (1) a water-dispersible acrylic polymer comprising chemically reacted or chemically non-reacted hydroxyl, phospho, phosphonate, sulfo, sulfonate, carboxy, or carboxylate groups, and (2) a water-dispersible polyester that has a Tg of 30° C. or less. The water-dispersible acrylic polymer is present in an amount of at least 55 weight % and at a dry ratio to the water-dispersible polyester of at least 1:1. The thermal image receiver element can be used to prepare thermal dye images after thermal transfer from a thermal donor element.