Variable Tread Width Pick Roll for Media Alignment
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Solution Overview
Problem
Existing media feed systems struggle to correctly align both wide and narrow media sheets in image forming devices, as the force applied by the pick mechanism can lead to incomplete skew correction and varying bubble stiffness, affecting the alignment process.
Innovation Solution
A media feed system utilizing a D-shaped pick roll with multiple tread width portions, where the pick tire has a wide tread portion and a narrow tread portion, providing different feeding forces to manage various media sizes effectively, and an aligner positioned transverse to the media feed path to ensure proper alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single tread width pick tire is used to feed all media sizes, then the device complexity is reduced, but the alignment precision deteriorates for narrow media
Solution Approach 1:
The pick tire is segmented into multiple tread width portions (first tread width portion and second tread width portion) that can be selectively positioned. This segmentation allows the pick tire to provide different feeding forces for different media widths, improving alignment precision for narrow media while maintaining simplicity through a single tire component rather than multiple tires.
Solution Approach 2:
The pick tire employs rotatable elements or movable tread portions that can dynamically adjust the effective tread width in contact with the media. This dynamic adjustment allows optimization of feeding force for each media size, enabling precise alignment across varying media widths while using a single adaptable tire structure.
2Force
If a wider tread width is used to feed narrow media, then the feeding force is sufficient, but the media skew correction deteriorates
Solution Approach 1:
Different portions of the pick tire have different tread widths optimized for specific media sizes. The first tread width portion provides sufficient feeding force for narrow media, while the second tread width portion is optimized for wider media. This local differentiation of properties allows each portion to perform optimally for its intended media size range.
Solution Approach 2:
The pick tire design changes the physical parameter of tread width to optimize feeding force and skew correction. By having multiple tread width portions, the system can change the effective contact parameter between the pick tire and media based on media size, thereby achieving both sufficient feeding force and proper skew correction for each media type.
3Manufacturing precision
If a narrower tread width is used to improve skew correction, then the alignment precision improves, but the feeding force becomes insufficient
Solution Approach 1:
The pick tire is divided into segments with different tread widths, where each segment can be selectively engaged with the media. This segmentation ensures that sufficient feeding force is always available through the appropriate tread width portion, while the alignment precision is maintained through proper selection of the engaging portion based on media size.
4Device complexity
If the pick tire applies constant feeding force, then the device complexity is reduced, but the bubble formation quality deteriorates for different media widths
Solution Approach 1:
The pick tire incorporates local variations in tread width to naturally provide different feeding forces for different media widths. This local quality differentiation allows proper bubble formation for each media type without requiring complex active control mechanisms, as the physical structure itself adapts to the media size.
Solution Approach 2:
The pick tire structure itself provides the adaptive feeding force through its multiple tread width portions, eliminating the need for external control systems. The system self-adjusts based on media size through the selective engagement of different tread portions, thereby maintaining bubble formation quality without adding device complexity.
Data Source
AI summary
A center-fed media feed system including a media sheet pick mechanism having a hub-mounted D-shaped pick tire having variable tread width along the outer circumference thereof and a media aligner downstream of the pick mechanism. The nip of the pick tire contacting a media sheet is disposed at a first predetermined distance from the media aligner. A wide tread portion initially contacts a leading edge portion of the media sheet providing a first media feeding force to move the media sheet toward the media aligner and, at a second predetermined distance between the leading edge of the media and the media aligner, a narrow tread portion of the pick tire contacts the media so as to provide a reduced media feeding force, allowing the media sheet to align to the media aligner and then be fed into a feed nip in the media aligner or a downstream feed roll pair.