Multi-Point Sheet Skew Detection for Jam Prevention
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Solution Overview
Problem
Conventional sheet feeding devices fail to detect skew in sheets due to rotation or deformation, especially when sheets are stapled or caught, leading to potential damage or jamming during the feeding process.
Innovation Solution
A sheet feeding device equipped with moving-amount detecting units, such as encoders, at multiple points in the sheet's width direction, which detect the moving amount of the sheet and a skew detecting unit that calculates the skew based on these moving amounts, allowing for real-time detection of sheet skew even after the leading edge has passed through the detection points.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sheet detecting units are arranged to detect the leading edge of the sheet, then the skew angle can be obtained based on time difference, but skew occurring after the leading edge passes through the detecting units cannot be detected
Solution Approach 1:
The invention transitions from detecting only the leading edge (one-point detection) to detecting multiple points across the sheet width simultaneously. By arranging sheet detecting units in parallel across the width direction, the system measures skew at multiple cross-sections along the feeding direction, adding a spatial dimension to the detection coverage and enabling comprehensive skew detection throughout the sheet.
Solution Approach 2:
The invention divides the sheet into multiple detection zones by placing multiple sheet detecting units across the width. Each detecting unit independently monitors its local section, and the control unit integrates information from all segments to determine overall skew. This segmentation allows continuous monitoring of the entire sheet rather than relying on a single leading edge measurement.
2Measurement precision
If multiple sheet detecting units are arranged in parallel across the width direction, then the structure complexity increases, but the detection accuracy and reliability improve
Solution Approach 1:
The sheet detecting units serve multiple functions: they detect the leading edge position, measure skew angle, and monitor skew development throughout the sheet. The same physical detecting units are used for both initial skew detection and continuous monitoring during feeding, eliminating the need for separate detection systems and reducing overall device complexity despite the multi-point arrangement.
Data Source
AI summary
A plurality of moving-amount detecting units respectively detects a moving amount of the sheet fed by a feeding unit at a plurality of points in a width direction of the sheet. A skew detecting unit detects a skew of the sheet based on the moving amount of the sheet detected by the moving-amount detecting units.