Tablet Inkjet Ink Composition for Transfer-Durable Printing
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Solution Overview
Problem
Existing inkjet inks for tablets suffer from poor ink fixedness (transfer durability) while maintaining excellent printing stability, leading to external defects and reduced productivity due to ink transfer between tablets.
Innovation Solution
An inkjet ink formulation comprising edible dyes, a liquid adhesive (polyethylene glycol), and solvents (water and ethanol) is developed, with specific compounding ratios to enhance ink fixedness and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the amount of drying solvent in the ink is increased to improve ink drying properties and fixedness, then ink transfer between tablets is suppressed, but drying of the nozzle liquid surface is promoted and printing stability deteriorates
Solution Approach 1:
The invention changes the chemical composition parameters of the ink by introducing a specific liquid adhesive (polyethylene glycol with average molecular weight 280-420) and controlling its content within 1-7 mass%, while also controlling drying solvent content at 6-15 mass%. This parameter optimization resolves the contradiction by achieving both improved fixedness and maintained printing stability through balanced formulation.
Solution Approach 2:
The invention creates a composite ink formulation combining edible dye, liquid adhesive (polyethylene glycol), drying solvent, and wetting agent in specific proportions. This composite approach allows the liquid adhesive to provide fixedness enhancement while the wetting agent and solvent system maintain printing stability, preventing both ink transfer and nozzle drying issues.
2Reliability
If a solid or gel-type adhesive is added to improve ink fixedness, then ink transfer is suppressed, but printing quality such as intermittent resumability deteriorates
Solution Approach 1:
The invention changes the physical state parameter of the adhesive from solid or gel to liquid form, specifically using polyethylene glycol with average molecular weight 280-420 which is liquid at room temperature. This parameter change allows the adhesive to remain soluble in the ink system, maintaining printing quality and intermittent resumability while still providing the necessary fixedness improvement.
3Reliability
If an inkjet ink with high ink drying properties is used to suppress unintended transfer, then ink fixedness is improved, but the ink may cause external defects and reduce productivity
Solution Approach 1:
The invention optimizes the drying solvent content parameter to 6-15 mass% and introduces liquid adhesive at 1-7 mass%, creating a balanced formulation that achieves sufficient fixedness without excessive drying speed. This prevents external defects while maintaining high production efficiency by avoiding rework and defects.
Solution Approach 2:
The liquid adhesive acts as an intermediary substance that enhances ink fixedness without requiring high drying solvent content. It mediates between the need for transfer prevention and the need to maintain printing stability and productivity, allowing moderate solvent levels that prevent both ink transfer and printing defects.
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 inkjet ink improves ink fixedness and maintains excellent printing stability, preventing unintended transfer and enhancing productivity by ensuring proper adhesion to tablet surfaces.
Implementation Method 1
an inkjet ink for a tablet... includes an edible dye, an adhesive, and water and ethanol as a solvent, and includes only a liquid adhesive as the adhesive
Data Source
AI summary
An object of the present invention is to provide an inkjet ink in which fixedness (transfer durability) of the ink is improved while maintaining excellent printing stability, and a tablet printed matter including a printing portion printed with the inkjet ink. The inkjet ink according to the present embodiment includes an edible dye, an adhesive, and water and ethanol as a solvent, and only a liquid adhesive as the adhesive.