Piezo Ink Jet Head Discharge Control for Diketopyrrolopyrrole Pigment Stability
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Solution Overview
Problem
The ink jet printing method using diketopyrrolopyrrole pigments faces issues with discharge stability due to their high hydrophobicity, leading to foreign matter occurrence and cavitation, which affects the quality of images on fabrics.
Innovation Solution
The use of a piezo ink jet head with a specific discharge amount to volume ratio and a solvent with a solubility parameter (SP) value of 13 or lower in the ink jet ink composition helps suppress foreign matter occurrence and improves discharge stability, ensuring excellent color developing properties and abrasion resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a highly hydrophobic pigment such as diketopyrrolopyrrole is used, then color developing properties and abrasion resistance are improved, but foreign matter occurrence and cavitation increase leading to poor discharge stability
Solution Approach 1:
The patent changes the chemical parameters of the solvent by selecting solvents with specific solubility parameters (SP values between 9.0-13.0) and controlling the pigment concentration (3-10% by mass). This parameter optimization allows the highly hydrophobic diketopyrrolopyrrole pigment to maintain its color developing properties while preventing foreign matter occurrence and cavitation, thus resolving the contradiction between abrasion resistance and discharge stability.
2Strength
If a highly hydrophobic pigment such as diketopyrrolopyrrole is used, then color developing properties are improved, but dispersion stability in ink is reduced
Solution Approach 1:
The patent optimizes the solvent's solubility parameter (SP value) to fall within the specific range of 9.0-13.0, which creates optimal chemical compatibility with the hydrophobic pigment. This parameter change enables the pigment to maintain stable dispersion in the ink formulation while preserving its excellent color developing properties, resolving the contradiction between color performance and dispersion stability.
3Productivity
If the discharge amount per droplet ejection is increased, then printing speed is improved, but discharge errors and foreign matter occurrence increase
Solution Approach 1:
The patent establishes an optimal discharge amount per droplet ejection of 0.13% to 0.18% of the ink pressure chamber volume. This precise parameter control enables efficient printing speed while preventing discharge errors and foreign matter occurrence, resolving the contradiction between productivity and manufacturing precision.
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
This approach results in stable ink jet printing with reduced discharge errors, enabling the production of high-quality images with improved color density and thin line expression on fabrics while maintaining wash fastness.
Implementation Method 1
an apparatus including a piezo ink jet head satisfying the following Expression (1)
Implementation Method 2
a solvent having a SP value of equal to or lower than 13
Implementation Method 3
the cavitation is expected to cause the diketopyrrolopyrrole pigment to contain microbubble nucleus
Data Source
AI summary
An image forming method includes discharging an ink jet ink composition which contains a diketopyrrolopyrrole pigment and a solvent having a SP value of equal to or lower than 13 by using an apparatus including a piezo ink jet head satisfying the following Expression (1).0.13≦{(discharge amount per droplet ejection)/(volume of ink pressure chamber)}×100 (1)