Variable Width Plenum Apertures for Media Hold Down Leakage
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Solution Overview
Problem
Current image production devices face challenges in maintaining adequate hold down pressure and sheet flatness due to open port leakage when transporting media sheets smaller than the plenum width, which is exacerbated by the complexity and cost of separate air sources and impedance balancing systems.
Innovation Solution
The apparatus includes a media transport belt with belt apertures and a vacuum plenum assembly with apertures of varying widths, allowing for adjustable alignment to secure media sheets, and a media transport shift assembly that adjusts the relative position between the belt and plenum to optimize airflow and minimize leakage across different media sizes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional multi-belt vacuum belt transport systems are used to transport media sheets, then adequate control over the substrate and sheet flatness are provided, but open port leakage occurs when running sheets smaller than the plenum width, reducing hold down pressure
Solution Approach 1:
The plenum aperture widths are varied across the cross-process direction, with narrower apertures positioned over smaller media and wider apertures over larger media. This local differentiation of aperture dimensions optimizes the balance between maintaining adequate hold down pressure and minimizing open port leakage for different media sizes, directly resolving the contradiction between reliability and harmful leakage.
Solution Approach 2:
The system dynamically adjusts the relative position between the media transport belt and vacuum plenum assembly in the cross-process direction to align belt apertures with plenum apertures. This dynamic alignment ensures optimal airflow distribution and minimizes leakage for different media sizes, maintaining hold down pressure while reducing open port leakage.
2Reliability
If separate air sources are used to reduce pressure drop, then hold down pressure is maintained, but system complexity and cost increase
Solution Approach 1:
A single vacuum plenum assembly with varied aperture widths serves multiple functions: it provides vacuum support for different media sizes, reduces pressure drop, and minimizes leakage. This multi-functional design eliminates the need for separate air sources for each media size, maintaining hold down pressure while reducing system complexity.
Solution Approach 2:
The system changes the physical parameter of plenum aperture width across the cross-process direction to optimize airflow characteristics. By varying aperture dimensions rather than using separate air sources, the system maintains hold down pressure and reduces pressure drop without increasing system complexity or cost.
3Object-generated harmful factors
If impedance balancing is used to reduce leakage, then open port leakage is minimized, but acquisition flow for wider sheets is reduced
Solution Approach 1:
Different regions of the plenum have different aperture widths optimized for their specific media sizes. This local quality differentiation allows each region to minimize leakage for its designated media while maintaining adequate acquisition flow, resolving the contradiction between leakage reduction and flow maintenance.
Solution Approach 2:
The plenum is segmented into multiple aperture regions with different width characteristics, each optimized for specific media sizes. This segmentation allows independent optimization of leakage and flow characteristics for different media types, preventing the trade-off between leakage reduction and acquisition flow.
4Object-generated harmful factors
If internal cross process chamber gating or valving is implemented, then open port leakage is reduced, but system complexity increases significantly
Solution Approach 1:
Instead of using complex gating or valving systems, the invention achieves leakage reduction through local quality differentiation of plenum aperture widths. This simpler approach minimizes open port leakage without requiring complex internal cross process chamber gating or valving mechanisms.
Solution Approach 2:
The invention replaces complex, expensive gating or valving systems with a simpler, more cost-effective design using varied aperture widths in the plenum. This approach achieves the same leakage reduction function with significantly reduced system complexity and lower cost.
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 solution enhances media hold down efficiency and reduces leakage, maintaining high hold down pressure while accommodating various media sizes without the need for multiple air sources or complex impedance balancing, thereby improving the overall performance of image production devices.
Implementation Method 1
Substantial vacuum pressure is applied from a vacuum plenum through holes in each vacuum belt and in a concentrated manner onto an image carrying substrate being transported
Data Source
AI summary
An apparatus (100) and method (300) for media hold down transport air flow in an image production device is disclosed. The apparatus can include a media transport belt (110) configured to transport media sheets (105) in a process direction (116). The media transport belt can include a plurality of belt apertures (115) arranged along a cross-process direction (118), where the cross-process direction is perpendicular to the process direction. The plurality of belt apertures can be configured to conduct air to secure the media sheets on the media transport belt. The apparatus can include a vacuum plenum assembly (120). The vacuum plenum assembly can include a plurality of plenum apertures (125) arranged along the cross-process direction. The plurality of plenum apertures can be configured to conduct air through at least some of the plurality of belt apertures. The plurality of plenum apertures can include at least a first plenum aperture (121) of a first width (123) in the cross-process direction and at least a second plenum aperture (122) of a second width (124) in the cross-process direction, where the first width can be different from the second width. The apparatus can include a media transport shift assembly (130) configured to shift a relative position between the media transport belt and the vacuum plenum assembly in the cross-process direction to align at least some of the plurality of belt apertures with at least some of the plurality of plenum apertures.