Inner Plenum Vacuum Roller System for Cut Sheet Printer Dryer Transport
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Solution Overview
Problem
Current printing systems using vacuum belt transport systems suffer from image defects due to differential drying of ink sets, particularly cyan, magenta, and yellow inks, as sheets of media remain in direct contact with the belt during transit through radiant dryers, leading to temperature differences and varying material properties affecting drying rates.
Innovation Solution
An inner plenum vacuum roller system is introduced, where vacuum rollers rotate around a fixed stationary plenum, directing vacuum to the top portion to drive sheets between rollers without continuous contact, using adjustable plenums and baffles to optimize vacuum application based on media weight, size, and coating, and incorporating a processor for automated adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If vacuum belt systems are used to transport media through the dryer, then the media can be driven through the drying process, but the media remains in direct continuous contact with the belt causing image defects due to differential drying
Solution Approach 1:
The continuous belt is segmented into discrete vacuum rollers that contact the media only at specific intervals during the drying process. Each roller provides localized vacuum contact to advance the media without requiring continuous belt-media contact, thereby reducing differential drying effects while maintaining transport functionality.
Solution Approach 2:
The vacuum application occurs periodically as media passes between rollers rather than continuously. The media is driven through the dryer by intermittent vacuum contact at roller interfaces, allowing periods where the media is not in contact with the transport surface, thus minimizing temperature-related image defects.
2Force
If multiple belts with different properties are used in the vacuum system, then the vacuum force can be distributed across the media, but differential drying occurs due to temperature differences between belts
Solution Approach 1:
Instead of having multiple belts with different properties contact the media simultaneously, the system inverts the approach by using a single plenum chamber that distributes vacuum force through multiple rollers. The plenum remains at a relatively uniform temperature while individual rollers can be independently controlled or replaced, separating the force distribution function from the temperature variation problem.
Solution Approach 2:
The plenum chamber acts as an intermediary between the vacuum source and the media. It distributes vacuum force uniformly to multiple rollers without the rollers themselves being in direct thermal contact with each other, thereby eliminating the temperature differential issues that arise from multiple belts with different thermal properties.
3Speed
If the vacuum holes in the belt are used to drive the media, then the necessary drive force is provided, but the media contacts the same belt region throughout drying causing image defects
Solution Approach 1:
The system transitions from a static belt with fixed vacuum holes to dynamic vacuum rollers that rotate and present different surface regions to the media during the drying process. This rotational movement ensures that no single belt region contacts the media throughout the entire drying process, preventing localized temperature effects while maintaining drive speed.
Solution Approach 2:
The vacuum application moves from a two-dimensional belt surface to a three-dimensional rotating roller system. The media contacts different circumferential positions of the rollers as they rotate, adding a temporal dimension to the contact pattern and preventing sustained contact with any single region, thereby improving image uniformity.
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 system reduces image defects by minimizing continuous contact between the media and belt, ensuring consistent drying rates and improved image quality through controlled vacuum application and adjustable settings for varying printing jobs.
Implementation Method 1
Each vacuum roller among the plurality of vacuum rollers can include a plenum operable to direct the vacuum to a top portion of the vacuum roller to drive the sheet of media from one roller to a next roller among the plurality of vacuum rollers
Data Source
AI summary
A vacuum roller system and a method of operating the vacuum roller system can include a group of vacuum rollers operable to move a sheet of media through a dryer. The vacuum rollers do not require a vacuum to be drawn between the vacuum rollers. Each vacuum roller can include a plenum operable to direct the vacuum to a top portion of the vacuum roller to drive the sheet of media from one roller to the next roller. The plenum can engage vacuum holes in a rotating vacuum roller when the vacuum holes in the vacuum roller are aligned with the plenum.