Duplex Sheet Registration Using Angled Sensors
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Solution Overview
Problem
Existing duplex printers face challenges in achieving precise registration between images on the front and back sides of a sheet due to media sheet size changes during fusing, leading to registration errors that affect the alignment of images on both sides.
Innovation Solution
A method and system utilizing a pair of sheet edge position sensors with linear sensing areas aligned at a non-zero angle to measure the sheet length and skew angle, allowing for precise adjustment and registration correction to align images on both sides of the media sheet.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If media sheet is fused after printing on the first side, then the image is fixed to the sheet, but the sheet size changes causing registration errors
Solution Approach 1:
The system performs preliminary measurement of the sheet length using sensors before the fusing process. This allows the system to capture the sheet's dimensions in its original state and use this information to calculate compensation factors that will correct for the dimensional changes that occur during fusing, thereby maintaining registration accuracy while still allowing the image to be fixed.
Solution Approach 2:
The system detects and compensates for parameter changes in the sheet dimensions that occur during the fusing process. By measuring the sheet length before fusing and comparing it with the length after fusing, the system calculates compensation factors that adjust the positioning parameters for the second side printing, thereby maintaining registration accuracy despite the physical changes in the sheet.
2Manufacturing precision
If sheet length is not measured accurately, then the registration adjustment cannot be made, but measurement systems add complexity
Solution Approach 1:
The system introduces sensors as intermediary devices to measure the sheet length. These sensors act as mediators between the sheet and the control system, providing the necessary dimensional information without requiring complex measurement mechanisms. The sensors are integrated into the existing sheet path and work with the control system to calculate compensation factors for registration adjustment.
3Measurement precision
If multiple sensors are used to measure sheet edges, then measurement precision improves, but the system complexity increases
Solution Approach 1:
The measurement system is segmented into multiple sensors positioned at different locations along the sheet path. Each sensor measures the position of sheet edges at its specific location, and the control system integrates these measurements to calculate the overall sheet length and skew angle. This segmentation allows for distributed measurement functionality while maintaining manageable system complexity through modular sensor placement and independent operation.
Data Source
AI summary
Sheet registration method and system includes transporting a sheet including a leading edge and a trailing edge between a first and second sensor. The first and second sensors each have a linear sensing area with a longitudinal axis aligned at a non-zero angle to each other. The first and second sensors are adapted to identify positions of the leading edge and the trailing edge. An alignment of the sheet is adjusted responsive to a sheet length determined using the output from the first and second sensors.