Quinacridone Inkjet Ink Purification for Stable Nozzle Ejection
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Solution Overview
Problem
Inkjet recording liquids containing quinacridone pigment suffer from ejection displacement from the recording head and poor dispersion stability due to the presence of synthetic intermediates and sulfur-containing derivatives that adhere to the nozzle and ejection face, leading to aggregation and clogging.
Innovation Solution
The ink formulation includes quinacridone pigment with controlled sulfur concentration (1.0 to 6.0 ppm) and light absorbance (0.17 or less at a peak between 400 to 490 nm) to minimize the presence of synthetic intermediates and sulfur derivatives, ensuring proper dispersion and reducing adherence to the recording head components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If quinacridone pigment is used in inkjet recording liquid, then color quality is improved, but synthetic intermediates and sulfur-containing derivatives cause ejection displacement and poor dispersion stability
Solution Approach 1:
The patent extracts and removes harmful synthetic intermediates and sulfur-containing derivatives from the ink formulation through purification processes. This eliminates the substances that cause ejection displacement and nozzle clogging while preserving the beneficial quinacridone pigment for color quality.
Solution Approach 2:
The patent changes the concentration parameters of sulfur-containing compounds to extremely low levels (1.0-6.0 ppm total sulfur). By controlling these parameters within specific ranges, the ink achieves both good color quality from quinacridone pigment and stable ejection without harmful side effects.
2Stability of the object's composition
If sulfur-containing derivatives are present in ink, then pigment dispersion is enhanced, but adherence to nozzle and ejection face causes aggregation and clogging
Solution Approach 1:
The patent changes the concentration parameter of sulfur-containing compounds from higher levels that provide dispersion to extremely low levels (1.0-6.0 ppm). This parameter change eliminates nozzle clogging while maintaining pigment dispersion through alternative mechanisms.
Solution Approach 2:
The patent introduces alternative dispersing agents that act as intermediaries between the quinacridone pigment particles and the aqueous medium. These alternative dispersants provide the necessary dispersion stability without the harmful adherence properties of sulfur-containing derivatives.
3Ease of manufacture
If synthetic intermediates are present in ink, then pigment synthesis is simplified, but ejection displacement from recording head occurs
Solution Approach 1:
The patent extracts and removes synthetic intermediates from the final ink formulation through purification steps. This eliminates the ejection displacement problem while the pigment synthesis process itself remains simplified through efficient reaction pathways.
Solution Approach 2:
The patent performs preliminary purification actions during the ink manufacturing process to remove synthetic intermediates before the ink is used. This preliminary removal prevents ejection displacement issues while maintaining ease of manufacture through integrated purification steps.
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 suppresses ejection displacement and enhances dispersion stability, maintaining consistent ink ejection and improving the reliability of the inkjet recording process.
Implementation Method 1
supernatant liquid obtained by centrifuging the inkjet ink at 1,050,000 G for three hours
Implementation Method 2
In an ultraviolet and visible ray absorption spectrum of 25-fold diluent of the supernatant liquid, light absorbance at a predetermined peak is 0.17 or less
Data Source
AI summary
An inkjet ink contains quinacridone pigment and aqueous medium. A sulfur concentration in the 10-fold diluent of supernatant liquid obtained by centrifuging the inkjet ink at 1,050,000 G for three hours is 1.0 ppm or more and 6.0 ppm or less. In an ultraviolet and visible ray absorption spectrum of the 25-fold diluent of the supernatant liquid, light absorbance at a predetermined peak is 0.17 or less. The predetermined peak is a maximum peak in a wavelength range of 400 nm or more and 490 nm or less.