Moving Holder Sensor Unit for Sheet Edge Detection
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Solution Overview
Problem
Existing position detection apparatuses for image forming devices face challenges in accurately detecting sheet edge positions with a high degree of precision while maintaining a cost-effective and compact configuration, as they require multiple sensors for various sheet sizes, leading to increased costs and potential detection errors.
Innovation Solution
A position detection apparatus with a moving holder and sensor unit that includes multiple pairs of light emitting and receiving portions, where only the relevant pair of sensors corresponding to the sheet size is activated, reducing the need for extensive moving mechanisms and minimizing detection errors by ensuring accurate edge position detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a line sensor is arranged in a line to detect edge positions of sheets of all sizes, then the detection capability for various sheet sizes is improved, but the cost of the sensor and apparatus increases
Solution Approach 1:
The detection system is segmented into multiple discrete sensor pairs (first sensor pair, second sensor pair, third sensor pair) positioned at different locations. Each sensor pair is dedicated to detecting edge positions for specific sheet size ranges, replacing the need for a single complex line sensor that must handle all sheet sizes. This segmentation allows each sensor to be simpler and less expensive while collectively providing comprehensive detection capability.
Solution Approach 2:
The moving holder dynamically positions different sensor pairs at different locations along the sheet conveying path. By moving the holder to bring specific sensor pairs into the detection zone, the system adapts to different sheet sizes without requiring all sensors to be simultaneously active or positioned. This dynamic reconfiguration allows versatile detection while keeping individual sensor components simple and cost-effective.
2Length of moving object
If multiple pairs of sensors are arranged on the moving holder to detect edge positions of sheets of various sizes, then the moving distance is shortened, but the risk of detection error increases due to light from one sensor being received by adjacent sensors
Solution Approach 1:
The harmful optical interference is extracted and eliminated by ensuring that only one sensor pair is active at a time during detection. The controller selectively activates specific sensor pairs based on the detected sheet size, preventing light from active sensors from being received by inactive adjacent sensors. This extraction of the interference problem maintains detection accuracy while allowing multiple sensors to be arranged on the moving holder.
Solution Approach 2:
The system performs preliminary identification of the sheet size before activating the appropriate sensor pairs. By detecting the sheet size in advance and selectively activating only the relevant sensor pairs, the system prevents potential detection errors from occurring in the first place. This preliminary action ensures that no cross-talk or interference between adjacent sensors can affect the detection accuracy.
3Reliability
If a plurality of pairs of sensors is moved individually to prevent detection errors, then the detection accuracy is improved, but the cost and space for wiring increase
Solution Approach 1:
Multiple sensor pairs are merged into a single moving holder that moves together as one unit. This consolidation eliminates the need for separate moving mechanisms and individual wiring for each sensor pair, reducing overall wiring complexity and space requirements. The controller still selectively activates specific sensor pairs to maintain detection accuracy, but the physical structure is simplified by combining all sensors into one movable assembly.
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 enables precise detection of sheet edge positions with a simple and cost-effective configuration, reducing the risk of detection errors and maintaining a compact apparatus size by using a moving holder with multiple pairs of sensors that are selectively activated based on the sheet size.
Implementation Method 1
a light emitting portion and a light receiving portion which face each other so that an edge of a sheet passing through the sheet conveying path in the sheet width direction is enclosed
Data Source
AI summary
A position detection apparatus comprises a sensor unit 80 and a moving holder 81 and a holder drive portion 82. The sensor unit has a plurality of pairs of sensors, each of which includes a light emitting portion held on the first holding surface 81a and a light receiving portion held on a second holding surface 81b as a pair and which are arranged along sheet width direction, and the sensor unit detects the edge position of the sheet S while the holder drive portion moves the moving holder in the sheet width direction and every other light emitting portions in the plurality of pairs of sensors is turned on.