Inkjet Ink Surface Tension Control for Sagging Prevention
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Solution Overview
Problem
Inkjet recording apparatuses with lineheads often experience white lines and sagging in unprinted portions due to ink with low static surface tension, which compromises image quality and printing speed.
Innovation Solution
An inkjet ink formulation containing a pigment, pigment dispersion resin with an acid value of 55-97 mgKOH/g, and a polymer nonionic surfactant with a molecular weight of 7,000-12,500, optimizing dynamic and static surface tensions to enhance permeability and prevent sagging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ink with low static surface tension is used to improve permeability to recording medium, then wet spreadability on recording medium is improved, but sagging occurs in unprinted portions and white lines appear in formed images
Solution Approach 1:
The patent applies parameter changes by precisely controlling the molecular weight of the polymer nonionic surfactant (7,000-12,500) and the acid value of the pigment dispersion resin (55-97 mgKOH/g). These parameter optimizations enable the ink to achieve appropriate dynamic surface tension (35-45 mN/m) and static surface tension (25-35 mN/m) balance, improving permeability while preventing sagging
Solution Approach 2:
The patent uses composite materials by combining specific components: polymer nonionic surfactant with controlled molecular weight, pigment dispersion resin with specific acid value, and water-soluble organic solvent. This composite formulation creates synergistic effects that resolve the contradiction between permeability and sagging prevention
2Reliability
If ink with low static surface tension is used to improve permeability to recording medium, then wet spreadability on recording medium is improved, but white lines occur in formed images
Solution Approach 1:
The patent applies parameter changes by precisely controlling the molecular weight of the polymer nonionic surfactant (7,000-12,500) and the acid value of the pigment dispersion resin (55-97 mgKOH/g). These parameter optimizations enable the ink to achieve appropriate dynamic surface tension (35-45 mN/m) and static surface tension (25-35 mN/m) balance, improving permeability while preventing white lines
Solution Approach 2:
The polymer nonionic surfactant acts as an intermediary that mediates between the ink components and the recording medium. It controls the surface tension characteristics to ensure proper ink penetration without causing white lines, bridging the gap between permeability requirements and image quality
3Productivity
If linehead inkjet recording apparatus is used to increase printing speed, then productivity is improved, but overprinting cannot be performed causing white lines
Solution Approach 1:
The patent applies parameter changes by optimizing the ink formulation parameters (surfactant molecular weight 7,000-12,500, resin acid value 55-97 mgKOH/g) to achieve surface tension values that enable single-pass printing without white lines, allowing linehead apparatus to maintain both high speed and image quality
Solution Approach 2:
The patent converts the potential harm of low static surface tension (which causes white lines) into a benefit by carefully controlling it within 25-35 mN/m range. This optimized range allows the ink to penetrate plain paper effectively without causing white lines, enabling high-speed linehead printing to produce quality images
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 ink achieves improved permeability and prevents sagging in unprinted areas, maintaining high image quality and printing speed while minimizing white lines, even in single-path type inkjet recording apparatuses.
Implementation Method 1
An inkjet ink with dynamic surface tension and static surface tension within a specific range is proposed as an example of an inkjet ink with excellent permeability to a recording medium
Implementation Method 2
The pigment dispersion resin has an acid value of at least 55 mgKOH/g and no greater than 97 mgKOH/g
Data Source
AI summary
An inkjet ink contains a pigment, a pigment dispersion resin, a water-soluble organic solvent, and a polymer nonionic surfactant. The pigment dispersion resin has an acid value of at least 55 mgKOH/g and no greater than 97 mgKOH/g. The polymer nonionic surfactant has a mass average molecular weight of at least 7,000 and no greater than 12,500. An inkjet recording apparatus includes a linehead and a conveyance section which conveys a recording medium. The linehead ejects the above inkjet ink onto the recording medium.