Ink Set Alkyl Diol Wettability VOC Reduction
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Solution Overview
Problem
Ink jet recording systems face challenges with high definition recording due to low boiling point solvents leading to VOC issues, instability in ink droplet discharge, and bleeding, which affect image quality and require increased driving speed or ink droplet amount, causing landing deviations and longer recording times.
Innovation Solution
An ink set comprising a first and second ink composition with specific alkyl diol content and pigment ratios, where the first composition has a higher pigment content and lower alkyl diol content, and the second composition has a lower pigment content and higher alkyl diol content, enhancing wettability and controlling pigment distribution, while minimizing VOCs and granular properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a penetrating agent having a low boiling point is used to improve wettability and permeability, then the ink can be discharged and spread on the recording medium, but the volatilization amount of organic solvent (VOC) becomes large
Solution Approach 1:
The patent changes the key parameter of the penetrating agent from low boiling point to high boiling point (240°C or higher), which fundamentally alters the volatilization characteristics. This parameter change allows the ink to maintain adequate wettability and permeability while dramatically reducing VOC emissions, as the high boiling point prevents excessive volatilization during and after the recording process
Solution Approach 2:
The patent creates a composite ink formulation by combining high boiling point penetrating agents with specific pigment concentrations (2.5% or higher) and other ink components. This composite approach balances the competing requirements of wettability, permeability, and low VOC, achieving a synergistic effect where the high boiling point agent provides sustained wetting without the harmful volatilization of low boiling point alternatives
2Quantity of substance
If the amount of ink droplet is increased to secure dot area and permeability, then the recording can be completed, but the landing deviation of the ink droplet causes deterioration in image quality
Solution Approach 1:
The patent changes the parameter of ink droplet size from small (which causes insufficient dot area) to larger sizes (10 picoliters or more). This parameter change, combined with the high boiling point penetrating agent, allows the larger droplets to maintain their integrity and spread controllably, reducing landing deviation while securing adequate dot area and permeability
3Productivity
If the driving speed of the recording head is increased to perform recording on larger size medium at high speed, then productivity improves, but the landing deviation of ink droplet increases causing deterioration in image quality
Solution Approach 1:
The patent changes the parameter of ink droplet size to larger amounts (10 picoliters or more), which provides greater mass and momentum to the droplet. This allows the ink to maintain stable flight characteristics at higher recording speeds, reducing the impact of landing deviation on image quality while enabling high-speed recording on large media
Solution Approach 2:
The patent formulates a composite ink system with high pigment concentration (2.5% or more) combined with high boiling point penetrating agents. This composite formulation ensures that even at high recording speeds, the ink maintains adequate permeability and wettability, allowing faster recording without sacrificing image quality
4Measurement precision
If a small amount of ink droplet is discharged to achieve high definition recording, then the resolution improves, but the dot area is insufficient and recording time becomes long
Solution Approach 1:
The patent changes the parameter of ink droplet size to larger amounts (10 picoliters or more), which directly increases the dot area and reduces the number of droplets needed to cover the same area. This parameter change, combined with high boiling point penetrating agents that enhance permeability, allows larger droplets to be used without compromising resolution, thereby reducing recording time and improving productivity
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 ink set improves image quality by reducing VOCs, stabilizing ink droplet discharge, and allowing for faster recording times without increasing driving speed, even with larger ink droplets or larger recording mediums, while maintaining small unevenness and granular properties.
Implementation Method 1
by increasing the content of the alkyl diol, it is possible to increase the wettability to the recording medium, and extend a dispersion region (region that spreads out wetly) of the pigment
Data Source
AI summary
An ink set includes a first ink composition, and a second ink composition, in which the first ink composition contains a first pigment, and an alkyl diol having carbon atoms of 6 or less and a normal boiling point of 240° C. or more, the second ink composition contains a second pigment, and the alkyl diol, in the first ink composition, a content of the first pigment is 2.5% by weightmass or more, and a content of the alkyl diol is 3% by weightmass to 15% by weightmass, in the second ink composition, a content of the second pigment is less than 2.5% by weightmass, and the content of the alkyl diol is 8% by weightmass to 30% by weightmass, and the content of the alkyl diol in the second ink composition is greater than the content of the alkyl diol in the first ink composition.