Inkjet Ink Viscosity Control for Ejection Stability
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Solution Overview
Problem
Existing inkjet recording inks used in circulation recording heads fail to achieve sufficient ejection stability, leading to issues with continuous printing accuracy.
Innovation Solution
An inkjet recording ink composition comprising a pigment, binder resin particles, and an aqueous medium that includes glycolether, a specific organic solvent (glycol compound with 3-6 carbon atoms), and water, with a specific content ratio and viscosity range to optimize ejection stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If an inkjet recording ink with high viscosity is used in a circulation recording head, then ejection accuracy during continuous printing is improved, but ejection stability becomes insufficient
Solution Approach 1:
The patent changes the chemical composition parameters of the aqueous medium by specifying exact ranges for glycolether (5-20 mass%), organic solvent (27.5-35.5 mass%), and water (75-69 mass%). This compositional parameter optimization achieves a shear viscosity of 5.5-7.0 mPa·s at 32°C, which simultaneously improves ejection accuracy and maintains ejection stability during continuous printing operations.
Solution Approach 2:
The patent creates a composite aqueous medium system combining three different solvent types (glycolether, organic solvent with 3-6 carbon atoms, and water). This composite solvent system works synergistically to achieve the target viscosity range and drying rate (20-40%), resolving the contradiction between ejection accuracy and ejection stability that cannot be achieved with single-solvent systems.
2Manufacturing precision
If the viscosity of the inkjet recording ink is increased to maintain ejection accuracy, then printing precision is improved, but the drying rate becomes unbalanced
Solution Approach 1:
The patent optimizes the viscosity parameter to a specific range (5.5-7.0 mPa·s at 32°C) and correlates it with the drying rate parameter (20-40%). This dual-parameter optimization is achieved by adjusting the solvent composition, ensuring that the ink dries at an appropriate rate while maintaining the viscosity necessary for precise ejection and printing accuracy.
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 recording ink achieves excellent ejection stability, preventing nozzle clogging and maintaining accurate printing performance due to its balanced viscosity and drying rate.
Implementation Method 1
The aqueous medium includes glycolether, a specific organic solvent, and water. The specific organic solvent is a glycol compound having 3 or more and 6 or less carbon atoms. A content ratio of the specific organic solvent is 27.5 mass % or more and 35.5 mass % or less. Shear viscosity of the inkjet recording ink measured at a temperature of 32° C. and a shear rate of 105 s−1 is 5.5 mPa·s or more and 7.0 mPa·s or less.
Implementation Method 2
A drying rate of the inkjet recording ink is 20% or more and 40% or less. The drying rate is obtained by the following formula (1) on the basis of a volume V0 of an ink droplet of the inkjet recording ink immediately after impact and a volume V1 of the ink droplet 500 ms after the impact
Data Source
AI summary
An inkjet recording ink includes: a pigment; a binder resin particle; and an aqueous medium. The aqueous medium includes glycolether, a specific organic solvent, and water. The specific organic solvent is a glycol compound having 3 or more and 6 or less carbon atoms. A content ratio of the specific organic solvent is 27.5 mass % or more and 35.5 mass % or less. Shear viscosity of the inkjet recording ink measured at a temperature of 32° C. and a shear rate of 105 s−1 is 5.5 mPa·s or more and 7.0 mPa·s or less. A drying rate of the inkjet recording ink is 20% or more and 40% or less.