Heat Transfer Sheet With Charge Control Layer For Light Toner
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Solution Overview
Problem
Existing heat transfer papers face challenges in transferring images with light toner coverage, especially on dark fabrics, and require weeding processes that are difficult around intricate designs, leading to incomplete transfers and undesirable background coating.
Innovation Solution
A method using a colorless fusible polymer material printed on a transfer sheet, which is then fused with a meltable coating layer and transferred to a substrate, allowing for precise image transfer without coating unimaged areas, utilizing two heat transfer steps to ensure complete and accurate image placement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional toner printers are used for heat transfer, then colored images can be transferred, but light-colored images with insufficient toner coverage result in faded or void spots
Solution Approach 1:
A charge control layer is introduced as an intermediary between the toner image layer and the substrate. This layer contains charge control particles that generate electrostatic charges to attract and hold toner particles, ensuring complete toner transfer even in light-colored image areas where insufficient toner is applied. The charge control layer acts as a mediator that compensates for inadequate toner coverage.
2Reliability
If a transfer coating is applied to the entire heat transfer paper, then complete coverage is achieved, but unimaged areas are also coated causing substrate stiffening and reduced moisture absorption
Solution Approach 1:
The invention applies transfer coating only to specific imaged areas rather than the entire paper surface. The charge control layer and toner image layer are selectively formed only where images are required, leaving unimaged areas of the substrate uncovered. This localized application maintains substrate porosity and moisture absorption properties in non-imaged regions while ensuring complete image transfer in imaged regions.
3Reliability
If weeding processes are used to remove coating from non-printed areas, then background coating is eliminated, but the process becomes difficult around intricate graphic designs
Solution Approach 1:
The mechanical weeding process is replaced with an electrostatic imaging system. Instead of manually cutting and removing coating from non-printed areas, the invention uses electrostatic charges to selectively attract and hold toner particles only in imaged areas. The charge control layer generates electrostatic fields that precisely control where toner adheres, automatically eliminating the need for manual weeding operations even for intricate designs.
4Adaptability or versatility
If dark fabric transfer paper with opaque layer is used, then white and colored images can be transferred on dark fabrics, but light toner coverage areas still do not transfer completely
Solution Approach 1:
The charge control layer serves as a mediator between the toner and the dark fabric substrate. It contains charge control particles that generate electrostatic charges to attract and hold light-toner particles, ensuring complete transfer of light-colored and white images on dark fabrics. The opaque layer provides background coverage while the charge control layer ensures reliable toner adhesion even with minimal toner application.
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
Enables efficient transfer of light-colored and mixed-color images, including white opaque images, on dark fabrics without the need for weeding, ensuring complete image transfer and minimizing background coating, thus improving image durability and appearance.
Implementation Method 1
a colorless fusible polymer material can be printed onto a printable surface of a printable transfer sheet to form an imaged area. The printable transfer sheet can be positioned adjacent to a coating transfer sheet such that the imaged area on the printable surface of the printable transfer sheet is adjacent to a meltable coating layer of the coating transfer sheet. Heat and pressure can be applied at a first transfer temperature to fuse the imaged area to the meltable coating layer.
Implementation Method 2
The intermediate coated imaged sheet can be positioned adjacent to the substrate such that the imaged area coated with the meltable coating layer is adjacent to the substrate, and heat and pressure can be applied at a second transfer temperature to the intermediate coated imaged sheet.
Data Source
Figure 1~3a
Figure 3b~3c
Figure 3d~3e
AI summary
Methods are generally provided of transferring an image to a substrate using a colorless fusible polymer material printed onto a printable surface of a printable transfer sheet to form an imaged area. The printable transfer sheet can be positioned adjacent to a coating transfer sheet such that the imaged area is adjacent to a meltable coating layer of the coating transfer sheet. The meltable coating layer and the imaged area can then be fused together, and the sheets separated to form an intermediate coated imaged sheet, such that the imaged area is coated with the meltable coating layer. The intermediate coated imaged sheet can be positioned adjacent to the substrate such that the imaged area coated with the meltable coating layer is adjacent to substrate, and heat and pressure can be applied. The intermediate coated imaged sheet can be separated from the substrate to leave the imaged area on the substrate.