Gel Ink Droplet Circularity in Indirect Printing
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Solution Overview
Problem
Indirect printing methods face challenges with gel inks that remain wet and contain high water content until transferred to a final substrate, and there is a need for improved ink droplet circularity to enhance print quality.
Innovation Solution
A gel ink composition is used in an indirect printing process where droplets are ejected onto an intermediate transfer member, undergo phase change to become substantially dry, and are then transferred to a final substrate, with specific properties such as high viscosity and controlled circularity to ensure proper placement and image integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If gel ink is applied as liquid to intermediate transfer member and quickly gelled, then the ink forms a gel structure on the transfer member, but the gel remains wet containing relatively large amounts of water and/or other liquid vehicles until transferred to final substrate
Solution Approach 1:
The patent changes the physical-chemical parameters of the ink composition by using sol-gel transition materials that undergo a phase change from sol (liquid) to gel (semi-solid) state. This parameter change allows the ink to form a stable gel structure on the intermediate transfer member while significantly reducing the liquid vehicle content, achieving both gel formation and reduced water content simultaneously.
Solution Approach 2:
The patent exploits the sol-gel phase transition phenomenon where the ink composition transforms from a liquid sol state during jetting to a gel state on the intermediate transfer member. This phase transition enables the ink to maintain structural integrity as a gel while reducing liquid content, and subsequently allows for dry transfer to the final substrate without excessive water content.
2Ease of manufacture
If gel ink is transferred wet to final substrate and then dried, then the transfer process is simpler, but the print quality is reduced due to poor ink droplet circularity on the intermediate transfer member
Solution Approach 1:
The patent applies preliminary action by ensuring the ink composition is pre-formulated with specific rheological properties that enable it to maintain circular droplet shapes on the intermediate transfer member during the gelation process. This preliminary preparation of the ink's flow and gelation characteristics ensures high circularity before transfer, improving print quality while maintaining process simplicity.
Solution Approach 2:
The patent utilizes parameter changes in the ink's viscosity and gelation kinetics to control droplet shape stability. By adjusting the sol-gel transition parameters, the ink maintains a circular profile on the intermediate transfer member during the brief window between jetting and gelation, achieving high manufacturing precision in droplet circularity.
3Manufacturing precision
If ink droplets are ejected onto intermediate transfer member with high viscosity, then circularity and placement accuracy improve, but the jetting process becomes more difficult
Solution Approach 1:
The patent applies dynamics by using an ink composition that exhibits time-dependent viscosity changes. The ink starts with lower viscosity during jetting for ease of manufacture, then rapidly increases in viscosity through sol-gel transition after deposition, achieving high droplet placement accuracy and circularity. This dynamic viscosity change resolves the contradiction between jetting ease and placement precision.
Solution Approach 2:
The patent employs parameter changes by controlling the ink's rheological properties to transition from a jettable state with suitable low viscosity to a gel state with high viscosity. This parameter transition occurs after deposition on the intermediate transfer member, allowing easy jetting process while achieving precise droplet placement and circularity through the subsequent gelation.
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 process results in a substantially dry ink pattern on the intermediate transfer member with improved circularity, reducing water content and enhancing print quality by maintaining ink integrity during transfer.
Implementation Method 1
Droplets of gel ink are ejected in an imagewise pattern onto an intermediate transfer member wherein each ink droplet forms a substantially circular image on the transfer member. The ink droplets are gelled and dried or solidified to form a substantially dry ink pattern on the intermediate transfer member.
Data Source
AI summary
An indirect printing process for printing a gel ink. The process comprises providing a gel ink composition in an inkjet printing apparatus. Droplets of gel ink are ejected in an imagewise pattern onto an intermediate transfer member wherein each ink droplet forms a substantially circular image on the transfer member. The ink droplets are gelled and dried or solidified to form a substantially dry ink pattern on the intermediate transfer member. The substantially dry ink pattern is transferred from the intermediate transfer member to a final substrate.