Moisture Profile Printing for Uniform Web Drying and Stability
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Solution Overview
Problem
Aqueous based inkjet printing introduces non-uniform moisture distribution across the print medium, leading to issues such as cockle formation, wrinkles, and creases due to differential expansion, and requires excessive drying power, which complicates color alignment and web handling.
Innovation Solution
Implementing a moisture profile in printing processes by using a processor to determine and apply a moisture profile based on the image and its negative, combined with controlled application of a moisturizing agent and ink composition, and employing a duplex printing system with arched print bars and simultaneous drying of both sides of the web.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If aqueous based inkjet printing is used to print images on print medium, then printing efficiency and productivity are improved, but non-uniform moisture distribution occurs leading to cockle formation, wrinkles, and creases
Solution Approach 1:
The patent applies local quality by using moisture map data to determine specific moisture application amounts for different regions of the print medium. The controller directs the moisturizing agent application device to apply moisture non-uniformly according to the printed image characteristics, ensuring that areas prone to over-drying receive additional moisture while areas that already have sufficient moisture receive less, thereby achieving uniform overall moisture distribution.
Solution Approach 2:
The patent implements preliminary action by applying a moisturizing agent to the print medium before the inkjet printing process. The moisturizing agent application device operates in advance to pre-condition the print medium with moisture based on the moisture map, which prevents cockle formation, wrinkles, and creases during subsequent printing and drying operations.
2Productivity
If excessive drying power is applied to remove moisture from printed areas, then drying efficiency is improved, but web handling complexity and color alignment difficulty increase
Solution Approach 1:
The patent applies local quality in the drying process by using the moisture map to control drying power distribution. The controller directs the drying device to apply different drying intensities to different regions of the web based on the moisture map data, ensuring that areas with higher moisture content receive stronger drying action while areas with lower moisture content receive gentler drying, thereby simplifying web handling and improving color alignment.
3Ease of operation
If moisture is applied uniformly across the print medium, then handling simplicity is improved, but printed areas become over-dried leading to shape changes
Solution Approach 1:
The patent applies local quality by implementing non-uniform moisture distribution based on the printed image characteristics. The controller uses moisture map data to direct the moisturizing agent application device to apply different amounts of moisture to different regions, ensuring that printed areas receive appropriate moisture levels while preventing over-drying, thereby maintaining both web handling simplicity and print quality.
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
Achieves uniform moisture content across the print medium, reducing shape changes and drying power requirements, enhancing print quality and stability, and facilitating predictable shrinkage for better packaging applications.
Implementation Method 1
Aqueous based inkjet printing may add a relatively large amount of moisture to the print medium substrate, but only in the printed area. In many instances, to fully (or at least sufficiently) dry the printed area, the unprinted area ends up being over-dried, thereby resulting in a moisture differential.
Implementation Method 2
Achieves uniform moisture content across the print medium, reducing shape changes and drying power requirements
Data Source
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AI summary
In an example, a method includes generating, using a processor, printing instructions of a print job, which instructions involve a moisture profile of an image to be printed on a print medium and a negative of the image. In some examples the method further includes disposing, using the printing instructions, a moisturizing agent over a first portion of the print medium to form the negative. The method may include disposing, using the printing instructions, an ink composition over a second portion of the print medium to form the image.