Thermal Transfer Printing with Resist Coating for Clean Image Edges

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Solution Overview

Problem

Current thermal transfer paper technology results in excess binder material being transferred to substrates, leading to aesthetic issues and a temporary bond that degrades over time, especially when laundered, due to uneven coverage and yellowing of non-imaged areas.

Innovation Solution

A resist layer is digitally printed over non-imaged areas of the transfer medium using inorganic materials like silica or alumina, preventing the transfer of binder materials and ensuring a durable bond by applying heat and pressure, while maintaining high image resolution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If binder materials are applied to cover the entire transfer medium substrate, then sufficient coverage is achieved, but excess binder material is transferred to the final substrate beyond the image area, reducing aesthetic quality and causing yellowing

Engineering Contradiction:
Improvebinder material coverageVSAvoidaesthetic quality degradation and yellowing
Core Design Contradiction:
Quantity of substanceVSObject-generated harmful factors

Solution Approach 1:

The patent applies a resist coating selectively only to those areas of the transfer medium that will not be imaged. This creates local differentiation where imaged areas receive full binder coverage for image transfer, while non-imaged areas receive resist coating to prevent excess binder transfer. The resist coating is applied at a concentration of 0.1 to 10% by weight of the binder material, creating a localized protective barrier that eliminates the harmful effect of excess binder transfer without affecting the overall coverage needed for image transfer.

Inventive Principle:
Principle #3Local quality

2Quantity of substance

If binder materials are applied to cover the entire transfer medium substrate, then sufficient coverage is achieved, but the bond between image and substrate becomes temporary and degrades over time, especially when laundered

Engineering Contradiction:
Improvebinder material coverageVSAvoidbond durability
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The resist coating is applied locally to non-imaged areas, creating a differentiated structure where imaged areas maintain full binder coverage for strong image bonding, while non-imaged areas are protected by resist. This local differentiation ensures that the bond durability is maintained in critical image areas while preventing degradation from excess binder in non-image areas during laundering and over time.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The transfer medium becomes a composite structure combining the original substrate with binder materials in imaged areas and resist coating in non-imaged areas. This composite approach creates distinct functional zones: the binder-rich imaged areas provide strong, durable bonding for image transfer and retention, while the resist-coated non-imaged areas prevent contamination and yellowing. The resist material itself forms a protective composite layer that enhances overall reliability without compromising bond strength.

Inventive Principle:
Principle #40Composite materials

3Quantity of substance

If the area of the transfer medium covered with binder materials is larger than the image area, then sufficient binder coverage is achieved, but the excess binder material is visible to the naked eye as a rectangle beyond the edges of the image

Engineering Contradiction:
Improvebinder material coverageVSAvoidimage boundary precision
Core Design Contradiction:
Quantity of substanceVSManufacturing precision

Solution Approach 1:

The resist coating is applied with precise spatial control to match the non-imaged areas exactly. This local application ensures that the resist barrier is present only where needed to prevent excess binder visibility, while leaving imaged areas untouched. The resist coating concentration of 0.1 to 10% by weight of binder material creates an optically appropriate barrier that prevents the visible rectangle effect without interfering with image quality or boundaries.

Inventive Principle:
Principle #3Local quality

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 resist layer effectively prevents the transfer of excess binder materials, enhancing the durability and aesthetic quality of the image on the substrate, with improved resistance to yellowing and laundering, while maintaining high image resolution.

Implementation Method 1

A resist layer is digitally printed over non-imaged areas of the transfer medium... preventing the transfer of binder materials

Methodology Applied
Scientific EffectPhysical barrier:

Implementation Method 2

applying heat and pressure, while maintaining high image resolution

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Data Source

PatentEP1816002B1Printing process and apparatus
Publication Date: 2009.02.18 SAWGRASS TECH INC
  • EP1816002B1 patent drawingFigure 1
  • EP1816002B1 patent drawingFigure 2a~2d

AI summary

A process of printing an image is disclosed in which a resist layer (14) is formed over an area of a printed transfer medium that has binders (4) or other materials thereon but is not covered by a printed image (12). The layer (14) resists transfer to the final substrate (16) of binder materials and other materials of the transfer medium that are not covered with the printed image.