Digital Printing Process Using Rotating Members for Liquid Removal
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Solution Overview
Problem
Inkjet printing on low- or non-absorptive recording media faces challenges such as prolonged drying times and insufficient rub-fastness due to slow absorption of liquid components, and conventional water-based inks struggle to produce high-quality images on these substrates.
Innovation Solution
A digital printing process using a water-based ink where a colorant-rich portion is left on the recording medium and a colorant-poor portion is adsorbed onto rotating members, allowing for efficient removal without absorption or heating, utilizing drying and volatile liquids to enhance ink removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If water-based inks are used on low- or non-absorptive recording media, then safety and environmental friendliness are improved, but image quality and rub-fastness deteriorate due to insufficient liquid removal
Solution Approach 1:
The ink is segmented into colorant-rich portion and colorant-poor portion through adsorption onto rotating members. This segmentation allows selective removal of the colorant-poor portion (carrier liquid and additives) while retaining the colorant-rich portion on the recording medium, thereby improving image quality and rub-fastness while maintaining the safety benefits of water-based inks.
Solution Approach 2:
The colorant-poor portion of the ink is extracted from the jetted ink through adsorption onto rotating members. This extraction removes excess carrier liquid and additives without removing the colorant, solving the problem of insufficient liquid removal that leads to poor image quality and rub-fastness.
2Object-affected harmful factors
If conventional water-based inks are printed on low- or non-absorptive recording media, then safety is improved, but drying time increases and rub-fastness decreases
Solution Approach 1:
The colorant-poor portion containing excess carrier liquid is extracted through adsorption onto rotating members immediately after jetting. This active removal of liquid components dramatically reduces drying time compared to passive evaporation, while maintaining the safety advantages of water-based inks.
Solution Approach 2:
The rotating members perform preliminary removal of excess carrier liquid and additives before the drying step. This preliminary action reduces the amount of liquid that needs to evaporate, thereby significantly reducing the overall drying time while maintaining safety.
3Quantity of substance
If heater or absorbing members are used to remove carrier liquid, then liquid removal is improved, but heat-sensitive recording media are damaged and incomplete removal occurs
Solution Approach 1:
The thermal or absorptive removal mechanism is replaced with a mechanical adsorption system using rotating members. The rotating members mechanically adsorb the colorant-poor portion through surface interaction, providing effective liquid removal without applying heat that could damage heat-sensitive recording media.
4Manufacturing precision
If solvent-based inks or UV-curable inks are used, then rub-fastness is improved, but environmental harm increases due to solvent diffusion or chemical hazards
Solution Approach 1:
The ink is segmented into colorant-rich and colorant-poor portions, allowing the colorant to be retained on the recording medium while the colorant-poor portion (containing carrier liquid and additives) is removed. This segmentation achieves rub-fastness comparable to solvent-based or UV-curable inks while maintaining the environmental benefits of water-based inks by eliminating harmful solvents and chemicals.
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 process enables fast and continuous printing with improved ink removal efficiency, reducing drying times and ensuring high-quality images on low- or non-absorptive media by separating and removing ink components effectively.
Implementation Method 1
bringing one or more continuously rotating members in rotational contact with the jetted ink on said recording medium, such that a colorant-poor portion of the ink is adsorbed to the one or more rotating members
Data Source
AI summary
A digital printing process for inkjet printing on a recording medium using ink including a carrier liquid and a colorant, in particular on a recording medium which is configured not to absorb the carrier liquid or to absorb only a portion of the carrier liquid during the inkjet printing. The process includes the steps of: jetting ink on the recording medium; bringing one or more continuously rotating members in rotational contact with the jetted ink on the recording medium such that a colorant-poor portion of the ink is adsorbed to the one or more rotating members and a colorant-rich portion remains on the recording medium. The colorant-rich portion includes more colorant than said colorant-poor portion. The process further includes continuously removing said colorant-poor portion of the one or more continuously rotating members.