Variable Path Substrate Cooler for Ink Printer Flatness
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Solution Overview
Problem
Aqueous ink printing systems face issues with substrate flatness due to water and solvent absorption, particularly in fibrous materials like paper, leading to wrinkling and distortion during the drying process, which affects the evenness of the printed substrates and their stackability.
Innovation Solution
A substrate cooler system with a variable path length and rollers actuated by a controller to maintain substrate flatness, utilizing a combination of rollers and belts to adjust the cooling path and duration, ensuring effective heat exchange and retention of flatness post-drying.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the dryer uniformly heats the entire substrate and ink to high temperatures to enable high speed operation, then drying efficiency is improved, but substrate flatness deteriorates due to water and solvent absorption causing wrinkling and distortion
Solution Approach 1:
The substrate cooler is positioned immediately after the dryer to begin cooling substrates as soon as they exit the drying zone. This preliminary cooling action prevents prolonged exposure to high temperatures that would cause excessive absorption and distortion, thereby preserving substrate flatness while maintaining high drying speeds.
Solution Approach 2:
The system rapidly changes the temperature parameter from high drying temperatures (100-140°C) to lower cooling temperatures immediately after drying. This rapid parameter change prevents the substrate from remaining in a vulnerable state where absorption causes distortion, thus maintaining flatness while achieving high productivity.
2Shape
If the substrate cooler uses a fixed cooling path, then device complexity is reduced, but substrate flatness preservation is insufficient because the cooling duration and effectiveness cannot be optimized
Solution Approach 1:
The substrate cooler employs adjustable cooling paths with variable lengths that can be dynamically configured. The cooler includes multiple rollers that can be positioned at different locations, allowing the cooling path length to be adjusted based on substrate type, ink coverage, and drying conditions. This dynamic adjustment optimizes cooling effectiveness and flatness preservation without requiring an overly complex fixed structure.
Solution Approach 2:
The cooling system is divided into multiple roller segments that can be independently positioned and adjusted. This segmentation allows flexible configuration of the cooling path length and cooling intensity at different zones, enabling effective flatness preservation while avoiding the need for a single complex monolithic structure.
3Productivity
If substrates are cooled quickly after drying, then handling efficiency is improved, but substrate flatness may deteriorate due to thermal shock or uneven cooling
Solution Approach 1:
The substrate cooler applies different cooling intensities to different regions of the substrate through multiple roller zones. Some rollers provide more intense cooling while others provide gentler cooling, creating a gradient that prevents thermal shock while maintaining overall cooling effectiveness. This local variation in cooling quality preserves flatness while enabling efficient handling.
Solution Approach 2:
The cooling process uses periodic contact between the substrate and cooling rollers, with the substrate being lifted and re-contacted in a rhythmic sequence. This periodic action distributes the cooling effect evenly across the substrate surface, preventing localized thermal shock and distortion while maintaining efficient cooling rates for rapid handling.
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 substrate cooler effectively preserves the flatness of printed substrates by varying the cooling path length and duration, ensuring substrates are cooled and handled without distortion, enhancing their usability and stackability.
Implementation Method 1
a substrate cooler configured to receive the substrates after the substrates have been dried by the dryer
Data Source
AI summary
An imaging system includes a substrate cooler that reduces the temperature of substrates bearing dried ink images. The substrate cooler has a plurality of rollers, at least one actuator operatively connected to the plurality of rollers, and a controller operatively connected to the least one actuator. The controller is configured to operate the at least one actuator to move the rollers relative to one another to vary the length of the path along which the substrates move through the substrate cooler.