Erasable Ink Composition Balancing Ejection and Erasing
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Solution Overview
Problem
Existing erasable ink compositions face issues with high viscosity due to polymer coagulants, leading to poor ejection performance and writing density, while reducing pigment particle size for better ejection results in poor erasing performance.
Innovation Solution
An ink composition with a specific relationship between colored resin particles and other components, including a 5 to 15 μm particle size and a specific gravity difference of 0.06 to 0.7, forms a film on the paper surface with a binder resin enfolding the particles, ensuring good ejection and erasability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a relatively large amount of polymer coagulant is added to suppress settling and separation of colored resin particles, then the stability of the ink composition is improved, but the viscosity increases resulting in poor ejection performance
Solution Approach 1:
The patent changes the particle size parameter of colored resin particles from conventional large sizes (2-30 μm) to a specific range (5-15 μm), and controls the specific gravity difference parameter between particles and other components to be within 0.06-0.7. This parameter optimization allows achieving stability without excessive polymer coagulant, thus maintaining good ejection performance.
2Productivity
If the particle size of pigment particles is reduced as small as possible to obtain good ejection performance and sufficient writing density, then the ejection performance is improved, but the pigment particles may penetrate the paper surface resulting in poor erasing performance
Solution Approach 1:
The patent optimizes the particle size parameter to a specific range of 5-15 μm, which is larger than conventional fine particles but smaller than coarse particles. This specific parameter range ensures that particles are small enough for good ejection performance and sufficient writing density, while large enough to remain on the paper surface for excellent erasability.
Solution Approach 2:
The patent creates a composite structure where colored resin particles are embedded in a binder resin matrix that forms a film on the paper surface. This composite approach allows the particles to be held in place by the binder resin, preventing penetration into the paper while maintaining erasability through the film structure.
3Quantity of substance
If the amount of colored resin particles is increased to obtain sufficient writing density, then the writing density is improved, but the viscosity increases resulting in poor ejection performance
Solution Approach 1:
The patent optimizes the particle size parameter (5-15 μm) and specific gravity difference parameter (0.06-0.7) to achieve sufficient writing density with appropriate particle concentrations. These parameter controls prevent excessive viscosity while maintaining adequate writing density, ensuring good ejection performance.
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 ink composition achieves sufficient writing density, appropriate ejection performance, and excellent erasability, with the film forming a stable layer on the paper that can be easily erased without smudging.
Implementation Method 1
forms a film in which the binder resin enfolds the colored resin particles on a paper surface
Implementation Method 2
The ink composition forms a film in which the binder resin enfolds the colored resin particles on a paper surface where the ink composition is ejected
Data Source
AI summary
An ink composition having erasability contains at least colored resin particles having an average particle size of 5 to 15 μm, a binder resin, and a solvent. A difference between a specific gravity of the colored resin particles and a specific gravity of components other than the colored resin particles is not less than 0.06 and not more than 0.7. The ink composition forms a film in which the binder resin enfolds the colored resin particles on a paper surface where the ink composition is ejected, without the colored resin particles settling on the paper surface.