Ink Jet Ink Thixotropy Control Bleeding Beading
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Solution Overview
Problem
Ink jet recording technologies face issues with clogging recoverability and the occurrence of bleeding and beading, particularly with pale inks used on low-absorbing recording media, where existing ink compositions fail to maintain optimal viscosity and surface tension.
Innovation Solution
An ink composition incorporating a sparingly water-soluble alkanediol and a resin, with a coloring material concentration of 1 to 3% by mass, and a thixotropic index within a specific range, which controls the surface tension between 21 to 25 mN/m and the thixotropic index from 2 to 110, effectively managing viscosity and flowability to prevent bleeding and beading.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the ink has low initial viscosity to improve clogging recoverability, then clogging recoverability is improved, but bleeding and beading occur more easily
Solution Approach 1:
The patent applies parameter changes by precisely controlling the surface tension (21-25 mN/m) and thixotropic index (2-110) of the ink to achieve the desired balance between low initial viscosity for clogging recoverability and suppression of bleeding and beading
Solution Approach 2:
The patent utilizes the dynamic viscosity characteristics of the ink, where the viscosity changes over time due to evaporation of volatile components, transforming the ink into a pseudoplastic fluid that exhibits different flow properties at different stages of the printing process
2Object-generated harmful factors
If the ink viscosity is increased to suppress bleeding and beading, then bleeding and beading are suppressed, but clogging recoverability deteriorates
Solution Approach 1:
The patent employs dynamic viscosity control where the ink maintains low initial viscosity for good clogging recoverability but transforms into a pseudoplastic fluid with higher effective viscosity during printing to suppress bleeding and beading
Solution Approach 2:
The patent changes the physical parameters of the ink over time through controlled evaporation of volatile components, transforming the viscosity characteristics from low initial viscosity to higher pseudoplastic viscosity to resolve the contradiction
3Object-generated harmful factors
If the thixotropic index is increased to suppress bleeding and beading, then bleeding and beading are suppressed, but the ink becomes too viscous for proper discharging
Solution Approach 1:
The patent optimizes the thixotropic index within a specific range (2-110) to achieve the right balance between suppressing bleeding and beading and maintaining proper ink discharging characteristics
Solution Approach 2:
The patent relies on the dynamic nature of thixotropic fluids where the viscosity decreases under shear stress during discharging but increases when stationary, allowing high thixotropic index without compromising discharging 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 ensures excellent clogging recoverability and suppresses bleeding and beading, maintaining image quality and natural color gradation by regulating viscosity and surface tension, thereby enhancing the performance of ink jet recording.
Implementation Method 1
by progress of evaporation of the ink on the recording medium, that is, volatilization of the volatile components, a pseudoplastic fluid (which will be described later) is exhibited early, and thus, occurrence of blurring or bleeding (which will be described later) is suppressed effectively
Implementation Method 2
by progress of evaporation of the ink on the recording medium, that is, volatilization of the volatile components
Implementation Method 3
controlling the surface tension and the thixotropic index (TI) of the ink within the predetermined range, such an effect can be attained
Data Source
AI summary
The ink for ink jet recording includes a sparingly water-soluble alkanediol, a resin, and a coloring material, wherein the content of the coloring material is from 1 to 3% by mass based on the total mass of the ink, the surface tension is from 21 to 25 mN/m, and the thixotropic index (TI) represented by the following formula (1), as determined at a time point when its content becomes 40% by mass based on the total mass before the evaporation of the ink by the evaporation of the ink, is from 2 to 110:TI=η(1 s−1)/η(1000 s−1) (1).