Ink-Jet Recording Ink pH Adjustment to Prevent Foam Adsorption
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Solution Overview
Problem
Ink-jet recording using solvent dyes with polyurethane foams in ink cartridges often results in reduced printing density and hue changes due to dye adsorption onto the foam, affecting image quality.
Innovation Solution
Formulating the ink with a solvent dye of specific structure and adjusting the pH to no more than 3.5, using a water-soluble organic solvent, and incorporating a pH adjuster to minimize dye adsorption onto the polyurethane foam, thereby maintaining stable printing density and hue.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If solvent dye is used in ink-jet recording with polyurethane foam, then color developing properties and water resistance are improved, but printing density decreases and hue changes due to dye adsorption onto the foam
Solution Approach 1:
The patent changes the pH parameter of the ink to be 3.5 or lower, which fundamentally alters the chemical environment to prevent dye-foam interactions. This parameter change resolves the contradiction by maintaining dye solubility and preventing adsorption onto the polyurethane foam, thereby preserving both water resistance and printing density
2Reliability
If solvent dye is used in ink-jet recording with polyurethane foam, then color developing properties are improved, but printing density decreases due to dye adsorption onto the foam
Solution Approach 1:
By adjusting the pH parameter to 3.5 or lower, the patent prevents the chemical interaction between solvent dye and polyurethane foam that causes adsorption. This maintains high concentration of free dye molecules in the ink, ensuring both excellent color developing properties and stable printing density
3Duration of action of stationary object
If ink containing solvent dye is stored in ink chamber with polyurethane foam for prolonged time, then ink stability is maintained, but image quality reduces due to dye adsorption
Solution Approach 1:
The patent applies preliminary anti-action by pre-adjusting the ink pH to 3.5 or lower before storage, which proactively prevents dye adsorption onto the polyurethane foam during prolonged storage. This anticipatory measure maintains both ink stability and image quality over extended storage periods
Solution Approach 2:
The pH parameter adjustment to 3.5 or lower creates a chemical environment that prevents dye-foam interactions throughout the storage period, ensuring that both storage stability and image quality are maintained without degradation
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 solution effectively prevents dye adsorption, ensuring high image quality with stable printing density and minimal hue changes, even after prolonged storage, by adjusting the pH and using specific solvent dyes and additives.
Implementation Method 1
the dye is adsorbed into the polyurethane foam due to interaction between the solvent dye and the polyurethane foam
Implementation Method 2
adjusting the pH to no more than 3.5
Data Source
AI summary
An ink for ink-jet recording includes a solvent dye in which a xanthene structure and a phthalide structure are spiro bound to each other. When the ink is stored in an ink cartridge containing a polyurethane foam and ink-jet recording is performed, a stable printing density may be achieved and changes in hue may be avoided.