Tilted Matrix Optical Sensor for Sheet Skew Detection
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Solution Overview
Problem
Conventional optical displacement sensors struggle to sensitively detect skew in sheet-like members, such as printing paper and belt members, due to their limited detection area and sensitivity to two-dimensional displacement, making it difficult to predict the life expectancy of rollers and maintain accurate image and document conveying in image forming and scanning processes.
Innovation Solution
A sheet conveying apparatus and belt drive apparatus equipped with an optical displacement sensor featuring a matrix array of light receiving elements tilted with respect to the conveying direction, allowing for the calculation of movement index values in both the conveying and perpendicular directions, enhancing the detection of skew and belt displacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional optical displacement sensor with a matrix array of light receiving elements is used, then the sensor can detect two-dimensional displacement, but the detection area is limited and sensitivity to skew detection is insufficient
Solution Approach 1:
The patent tilts the matrix array of light receiving elements relative to the conveying direction, transforming the detection geometry from a standard orthogonal arrangement to an angled configuration. This dimensional change allows the sensor to capture displacement components in both the conveying direction and the perpendicular direction with enhanced sensitivity, effectively converting a two-dimensional detection problem into a more sensitive measurement configuration that improves skew detection capability without requiring a larger detection area
2Device complexity
If the optical displacement sensor detects displacement in a narrow area, then the sensor structure remains compact, but it becomes difficult to sensitively detect the amount of skew
Solution Approach 1:
By tilting the matrix array at a specific angle relative to the conveying direction, the patent enables the compact sensor structure to detect skew with high sensitivity. The angular orientation allows the same compact detector to capture both longitudinal and lateral displacement components, effectively using geometric configuration rather than increased size or complexity to achieve sensitive skew detection
3Ease of manufacture
If the light receiving elements are arranged in a standard matrix configuration aligned with the conveying direction, then the sensor is easy to implement, but it cannot effectively detect skew in the direction perpendicular to conveying
Solution Approach 1:
The patent introduces an angular dimension to the matrix array arrangement, tilting it relative to the conveying direction. This configuration allows the sensor to simultaneously capture displacement information in both the conveying direction and the perpendicular direction with equal sensitivity, enabling effective skew detection while maintaining a relatively simple implementation based on standard matrix detector technology
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 configuration improves the sensitivity of skew detection, enabling more accurate prediction of roller life expectancy and maintaining precise conveying and image formation by effectively capturing displacement in both directions, thus preventing image skew and paper jams.
Implementation Method 1
an optical displacement sensor that detects displacement of the sheet-like member based on a result obtained by detecting light emitted from a light emitting element and reflected on a surface of the sheet-like member
Data Source
AI summary
A sheet conveying apparatus includes a conveying path for conveying a sheet, an optical displacement sensor that detects displacement of the sheet, and a calculating unit that calculates a movement index value indicating moving distances of the sheet in a conveying direction and a direction perpendicular thereto based on an output from the optical displacement sensor. The optical displacement sensor includes a plurality of light receiving elements arranged in a matrix array. A row alignment direction and a column alignment direction of the light receiving elements are tilted with respect to the conveying direction.