Aqueous Inkjet Ink Nozzle Drying and Mottling
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Solution Overview
Problem
Aqueous inkjet inks face issues with drying and solidification at the nozzle of inkjet heads when printing on non-absorbable or poorly-absorbable recording media, leading to ejection failures and uneven drying (mottling), which deteriorate print quality.
Innovation Solution
An aqueous ink formulation containing an acetylene-based surfactant and a nonionic surfactant that meets specific criteria, such as HLB values and clouding points, is used to prevent drying and solidification at the nozzle and ensure even wet-spreading on the recording medium.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If an aqueous pigment ink is used for printing on non-absorbable or poorly-absorbable recording medium, then the ink can be ejected from the nozzle, but the ink dries and solidifies at the nozzle portion over time causing ejection failure
Solution Approach 1:
The patent changes the chemical parameters of the aqueous ink by adding specific surfactants (anionic, cationic, or amphoteric) and controlling pH values (adjusted to 9.0 or higher using alkaline agents). This modifies the surface properties and drying characteristics of the ink, allowing it to remain fluid at the nozzle while still being capable of adhering to non-absorbable recording media.
Solution Approach 2:
The patent creates a composite ink formulation by combining multiple components: aqueous pigment ink base, surfactants (anionic/cationic/amphoteric), alkaline agents for pH adjustment, and optionally organic solvents. This composite formulation achieves both nozzle fluidity and recording medium adhesion that cannot be obtained with simple aqueous pigments alone.
2Reliability
If the ink is formulated to prevent drying at the nozzle portion, then ejection stability is improved, but uneven drying (mottling) occurs on the non-absorbable recording medium
Solution Approach 1:
The patent carefully controls multiple parameters including pH (adjusted to 9.0 or higher), surfactant concentrations, and optional organic solvent ratios. These parameter adjustments create a balanced formulation that dries uniformly on non-absorbable media while preventing premature solidification at the nozzle.
Solution Approach 2:
The surfactants act as intermediaries between the aqueous ink and the non-absorbable recording medium. They modify the surface tension and wetting properties, enabling controlled spreading and uniform drying on the recording medium surface while maintaining ink fluidity in the nozzle.
3Ease of operation
If conventional surfactants are used in the aqueous ink, then the ink can be ejected, but drying and solidification still occurs at the nozzle causing direction bending of ejection
Solution Approach 1:
The patent uses composite surfactant systems combining anionic, cationic, or amphoteric surfactants with specific alkaline agents. This composite approach creates a more stable colloidal system that maintains consistent surface tension and ejection trajectory, preventing the direction bending that occurs with conventional single-component surfactants.
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 formulation significantly reduces the likelihood of ejection failures and mottling, maintaining print quality and enabling clear, consistent images even on non-absorbable or poorly-absorbable media.
Implementation Method 1
an acetylene-based surfactant (A); a nonionic surfactant (B) other than the acetylene-based surfactant (A)
Implementation Method 2
ensure even wet-spreading on the recording medium
Data Source
AI summary
A problem to be solved by the invention is to provide an aqueous ink capable of forming a clear print image without causing deterioration in print quality due to uneven drying (mottling) of the ink even when continuous printing is performed for a long period of time or when printing is resumed after printing is suspended for several minutes to several hours. The invention relates to an aqueous ink containing: an acetylene-based surfactant (A); a nonionic surfactant (B) other than the acetylene-based surfactant (A); and an aqueous medium (C), in which the nonionic surfactant (B) contains a nonionic surfactant that satisfies at least one of the following three requirements: (i) having an HLB of less than 13.5, (ii) having a clouding point of 75° C. or lower, and (iii) having no clouding point.