Ink Composition for Plain Paper Image Quality and Ejection Stability
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Solution Overview
Problem
Ink-jet printers face challenges in achieving high image quality on plain paper while maintaining high-speed printing, storage stability, and ejection stability, with existing inks often compromising on viscosity and pigment dispersion, leading to issues like pinholes, poor reliability, and maintenance device damage.
Innovation Solution
A water-based ink composition comprising a colorant, wetting agents with high equilibrium moisture content, a surfactant, a penetrant, and a water-dispersible resin, which undergoes controlled evaporation and humidity absorption to achieve a high viscosity state for improved image quality and stability, preventing maintenance device adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the viscosity of the ink is increased to improve image quality and drying properties on plain paper, then the image quality and drying speed are improved, but the ejection stability deteriorates and maintenance devices suffer from adhesion and breakage
Solution Approach 1:
The patent changes the chemical composition parameters of the ink by introducing a specific polyhydric alcohol (1,2,4-butanetriol) with controlled content (5-30 wt%), along with specific surfactants and penetrants. This parameter change allows the ink to achieve both high viscosity for quality printing and appropriate ejection characteristics, resolving the contradiction between image quality and ejection stability
Solution Approach 2:
The patent creates a composite ink formulation combining multiple components: pigments, polyhydric alcohols, surfactants, penetrants, and water. This composite approach allows each component to contribute specific properties - the polyhydric alcohol provides viscosity and drying properties while the surfactant and penetrant ensure ejection stability and maintenance device compatibility, simultaneously achieving both contradictory requirements
2Productivity
If the hole diameter of nozzles is reduced to enable high-speed printing and miniaturized droplets, then printing speed and droplet size are improved, but ejection stability deteriorates due to pigment use
Solution Approach 1:
The patent modifies the ink's rheological parameters by adding specific surfactants (reducing surface tension to 20-35 mN/m) and penetrants, along with controlling polyhydric alcohol content. These parameter changes enable stable ejection from miniaturized nozzles (5-20 μm diameter) at high speeds while maintaining pigment suspension stability, resolving the contradiction between printing speed and ejection stability
3Speed
If the ink dries quickly to achieve high-speed printing, then drying speed and productivity are improved, but ejection stability deteriorates and maintenance devices are damaged by adhesion
Solution Approach 1:
The patent carefully balances the drying speed by controlling the solvent composition - using polyhydric alcohols with specific equilibrium moisture contents and combining them with volatile components. This parameter control achieves rapid drying (reducing productivity losses) while the surfactant and penetrant components prevent excessive adhesion to maintenance devices, resolving the contradiction between drying speed and maintenance device harm
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 ensures high-quality images on plain paper with enhanced drying properties and ejection stability, while being harmless to ink ejection device maintenance, thereby improving long-term reliability and reducing maintenance issues.
Implementation Method 1
when 2.5g of the ink is weighed, placed in a glass Petri dish having a diameter of 33mm and stored for 24hr at a temperature of 50°C±0.5°C and a humidity of 12%±5%, the evaporation rate of a solvent with respect to the total weight of the ink is 50% by weight or more
Implementation Method 2
by storing the ink residue for 6hr at a temperature of 23°C±0.5°C and a high humidity of 95%±3% to allow it to absorb moisture, the amount of moisture contained in the ink residue becomes 30% by weight to 40% by weight
Data Source
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AI summary
An ink-jet recording ink including a colorant dispersible in water, a water-soluble organic solvent used as a wetting agent, a surfactant, a penetrant, a water-dispersible resin, and water, wherein when 2.5g of the ink is weighed, placed in a glass Petri dish having a diameter of 33mm and stored for 24hr at a temperature of 5O°C+O.5°C and a humidity of 12%±5%, the evaporation rate of a solvent (water + water-soluble organic solvent) in the ink is 50% by weight or more, and an ink residue has a viscosity of 20,00OmPa-S or greater, and wherein by storing the ink residue for 6hr at a temperature of 23°C±0.5°C and a high humidity of 95%±3% to allow it to absorb moisture, the amount of moisture contained in the ink residue becomes 30% by weight to 40% by weight, in which case the ink residue has a viscosity of less than 500mPa · s.