Omnidirectional Roller Sheet Registration System
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Solution Overview
Problem
Existing sheet registration systems face challenges in accurately registering large and heavy sheets at high speeds due to reduced time for correction, leading to misalignment, sheet damage, and jams, as well as limitations in handling sheet-to-sheet variations.
Innovation Solution
A registration system utilizing omnidirectional rollers with adjustable axes of rotation, allowing sheets to slide and be driven in multiple directions, combined with a feedback system and sensors for real-time error correction, enabling simultaneous lateral and skew corrections without the need for manual module alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high sheet transport speeds are used, then printer productivity is improved, but registration correction time is reduced leading to increased misalignment and sheet damage
Solution Approach 1:
The registration system uses dynamically adjustable rollers that can change their position and orientation during sheet transport. The rollers are positioned to engage sheets at different locations along the transport path, allowing continuous registration correction rather than fixed-position correction. This dynamic adjustment enables effective registration even at high speeds where correction time is limited.
Solution Approach 2:
The registration system divides the correction function across multiple independently controllable rollers positioned at different locations. Rather than using a single correction mechanism, the system segments the registration task across several rollers that can operate simultaneously or sequentially, providing distributed correction capability that works effectively at high transport speeds.
2Ease of operation
If a translating carriage is used for lateral correction, then lateral and skew correction are decoupled, but the maximum printer speed is limited due to carriage return time
Solution Approach 1:
The invention extracts the lateral correction function from a moving translating carriage and implements it using stationary or minimally moving rollers. By removing the carriage component entirely, the system eliminates the carriage return time constraint while maintaining independent lateral correction capability through the positioned rollers.
Solution Approach 2:
The registration rollers serve as intermediaries that provide both lateral and skew correction functions without requiring a translating carriage. These rollers mediate the correction process by being positioned and oriented to handle both correction dimensions simultaneously or independently, eliminating the need for mechanical carriage movement.
3Measurement precision
If manual module alignment is used, then mean input error is reduced, but sheet-to-sheet variations still cause misregistration
Solution Approach 1:
The system incorporates sensors that detect the actual position and orientation of each sheet as it enters the registration system. This feedback information is used to dynamically adjust the roller positions and orientations to correct for both mean errors and sheet-to-sheet variations, ensuring consistent registration across all sheets regardless of initial misalignment.
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 allows for precise registration of large sheets at higher speeds, reducing misalignment and sheet damage, while minimizing the 'tail-wag' effect, thereby improving printer efficiency and handling capabilities.
Implementation Method 1
The omnidirectional rollers each allow the sheet to slide, relative to the omnidirectional roller, in a direction parallel to the axis of rotation of the omnidirectional roller
Data Source
AI summary
A registration system includes nip rollers for conveying a sheet in a process direction when the nip rollers are in an engaged position, and first and second sets of omnidirectional rollers arranged perpendicularly to each other, for conveying the sheet in the process and cross-process directions, respectively. The omnidirectional rollers each allow the sheet to slide, relative to the omnidirectional roller, in a direction parallel to an axis of rotation of the omnidirectional roller. The nip-rollers are movable from the engaged position to a disengaged position, in which the first pair of omnidirectional rollers convey the sheet in the process direction. A feedback system includes sensors for determining registration errors of the sheet and a control system controls the omnidirectional rollers to reduce the registration errors in the sheet while the nip-rollers are in the disengaged position.