Aqueous Ink Set Dynamic Surface Tension for Continuous Printing
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Solution Overview
Problem
Continuous inkjet printing systems face challenges in maintaining print quality due to sensitivity to image details and printing speed, particularly with high-speed printing of images containing abrupt changes between regions of continuous white and black, leading to defects like 'pick out' (PO) and 'dark defect' (DD), which affect the operating print margin.
Innovation Solution
An aqueous inkjet black ink composition with dispersed black pigment particles and a surfactant to achieve a 10-ms dynamic surface tension of less than 54 mN/m, along with a full color ink set comprising cyan, magenta, and yellow inks, each with similar surfactant properties, to improve fluid properties on the catcher face and reduce defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If air flow is increased to prevent dark defect, then print quality improves, but pick out defect increases
Solution Approach 1:
The patent modifies the physical-chemical parameters of the ink composition, specifically dynamic surface tension and viscosity, to enable more stable drop formation and trajectory control. This allows the printing system to operate with reduced air flow while maintaining print quality, thereby preventing both dark defect and pick out defect simultaneously.
Solution Approach 2:
The patent introduces dynamic adjustment capabilities for ink formulation parameters during high-speed printing operations. By dynamically optimizing ink properties such as surface tension and viscosity based on printing conditions, the system can maintain stable drop formation and trajectory control across varying speeds and image complexities, reducing sensitivity to air flow variations.
2Productivity
If printing speed is increased for productivity, then output improves, but print margin sensitivity increases
Solution Approach 1:
The patent formulates ink with optimized dynamic surface tension and viscosity parameters that remain stable under high-speed printing conditions. This formulation approach maintains consistent drop formation and trajectory control even at increased printing speeds, reducing the sensitivity of print margin to speed variations and enabling high-productivity operation without sacrificing print quality.
3Ease of manufacture
If ink composition is simplified for ease of manufacture, then production cost decreases, but foam formation increases
Solution Approach 1:
The patent carefully selects and balances the types and concentrations of surfactants and other ink components to achieve optimal dynamic surface tension and viscosity while minimizing foam formation. This parameter optimization allows for relatively simple ink formulations that are easy to manufacture yet produce minimal foam during high-speed printing operations.
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 solution enhances print margin and reduces defects like PO and DD, allowing for high-speed printing of demanding images with improved ink film stability and reduced foam formation, maintaining print quality and operational robustness.
Implementation Method 1
the at least one surfactant is selected to provide the ink composition with a 10-ms dynamic surface tension of less than 54 mN/m
Implementation Method 2
black pigment particles dispersed with a polymeric dispersant or self dispersing pigment particles
Data Source
AI summary
An aqueous inkjet ink set for use in continuous inkjet printing comprising at least one cyan ink, at least one yellow ink, at least one magenta ink, and at least one black ink, wherein each ink of the ink set comprises dispersed pigment particles and at least one surfactant selected to provide a 10-ms dynamic surface tension of less than 54 mN/m for each ink. The invention relates to continuous ink jet printing of aqueous pigmented ink compositions recycled from main ink supply reservoirs, employing a printer with drop ejectors and a drop deflector and non-printing drop catchers capable of returning unprinted ink to the fluid delivery systems following the capture of non-printing drops. The pigmented ink jet ink compositions provide for particularly suitable fluid properties on the drop catcher face that minimize printing defects that can occur during drop deflection during the printing of high dynamic range images at high speed.