Regenerative Intermediary Drive Roller for Printer Skew Control
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Solution Overview
Problem
Media skew and complex coordination challenges in high-speed sheet-fed printers lead to suboptimal printing quality, especially in duplex printing, due to variations in media alignment and drag forces, requiring a simplified mechanism to minimize skew and enhance handling efficiency.
Innovation Solution
A media feed mechanism featuring an intermediary drive roller assembly with a pivotally connected swing arm, providing a regenerative clamping force and tilt angle adjustment, which self-coordinates hand-offs between rollers without complex sensors, and a datum plate for side justification, minimizing skew and wear on rollers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a stationary pagewidth printhead is employed, then high-speed printing and noise reduction are achieved, but media skew becomes more problematic
Solution Approach 1:
The intermediary drive shaft is made arcuately moveable relative to the intermediary idler shaft through a swing arm mechanism, allowing dynamic adjustment of the drive roller position. This dynamic capability enables the system to compensate for media skew variations in real-time during high-speed printing operations
Solution Approach 2:
The swing arm mechanism provides self-coordinating hand-offs between the intermediary drive and main drive without requiring complex sensors or feedback systems. The regenerative clamping force automatically adjusts based on media drag forces, enabling the system to self-correct alignment issues during operation
2Ease of operation
If intermediary drive roller assemblies are used to guide media, then media handling is improved, but coordination complexity between rollers increases
Solution Approach 1:
The swing arm mechanism enables the intermediary drive shaft to self-adjust its position relative to the idler shaft based on media drag forces. This self-coordinating action eliminates the need for complex sensor systems and feedback control, reducing overall system complexity while maintaining effective media handling
Solution Approach 2:
The system uses passive feedback from media drag forces to automatically adjust the intermediary drive shaft position through the swing arm mechanism. The drag forces from the media itself provide the feedback signal that triggers the swing arm to move, creating a self-regulating system without external sensors
3Adaptability or versatility
If media passes through the print zone multiple times for duplex printing, then printing functionality is enhanced, but skew variations are exacerbated
Solution Approach 1:
The arcuately moveable intermediary drive shaft provides dynamic compensation for skew variations that occur during duplex printing. Each time media passes through the print zone, the swing arm mechanism can adjust the drive roller position to counteract accumulated skew, maintaining alignment for multiple passes
4Reliability
If fixed clamping force is applied by intermediary rollers, then media gripping is consistent, but roller wear increases
Solution Approach 1:
The system changes the clamping force parameter dynamically based on actual media drag forces. The regenerative clamping force increases with greater drag forces from the media, providing optimal gripping force for each media type and thickness while minimizing unnecessary wear from excessive constant force
Solution Approach 2:
The swing arm mechanism applies only the necessary clamping force required for effective media gripping, avoiding excessive force that would cause premature roller wear. The partial action of the swing arm movement provides just enough clamping force to grip media without over-compression
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 solution effectively minimizes media skew and reduces roller wear, enabling self-coordinated operation between intermediary and main drive rollers, improving printing quality and handling efficiency across various media types, including different thicknesses and stiffnesses, without the need for complex feedback systems.
Implementation Method 1
drag forces from the media sheets cause a reaction in the swing arm, which arcuately moves the intermediary drive shaft towards the intermediary drive shaft
Implementation Method 2
provides a regenerative clamping force between the intermediary drive and idler rollers. The clamping force is regenerative, because it increases with greater drag forces from the media
Data Source
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AI summary
A printer includes: a media tray; a picker; a media guide for guiding the media sheets around a media feed path towards a print zone; a main drive roller assembly positioned upstream of the print zone; and an intermediary drive roller assembly positioned between the picker and the main drive roller assembly. Theintermediary drive roller assembly includes: an intermediary idler roller mounted on an intermediary idler shaft; and an intermediary drive roller having a gripping surface engaged with the intermediary idler roller. An intermediary drive shaft is pivotally connected to a support shaft via a swing arm, such that the intermediary drive shaft is arcuately moveable relative to the intermediary idler shaft to provide a variable distance therebetween.