Edge Position Detection Using Multi-Wavelength LED Illumination
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Solution Overview
Problem
Conventional edge position detection sensors face challenges in accurately detecting paper edges due to varying paper colors and reflectance, leading to difficulties in maintaining image position accuracy and excessive power consumption when using multiple light sources.
Innovation Solution
An edge position detecting apparatus with a light emitting device featuring multiple LEDs of different wavelengths, which irradiates the paper in the width direction and a detecting device that calculates the edge position based on reflected light intensity, allowing for optimal light source selection and intensity adjustment to reduce power consumption and improve detection accuracy across various paper types.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple light sources with different wavelengths are sequentially turned on to identify paper edge position, then detection accuracy may be improved for certain paper colors, but it becomes difficult to obtain expected output power for papers with varying colors and reflectance
Solution Approach 1:
The patent changes the parameter of light source wavelength selection dynamically. Instead of sequentially testing multiple wavelengths, the system directly selects the optimal wavelength based on paper color classification (white, yellow, blue, green, red, black). This parameter change approach resolves the contradiction by ensuring reliable detection for each paper type without the complexity of sequential wavelength testing.
2Power
If a plurality of light sources are simultaneously turned on to increase light intensity, then output power is obtained independent of paper color or reflectance, but light intensity becomes excessive for paper with high reflectance and power consumption increases
Solution Approach 1:
The patent applies local quality by providing different light intensities for different paper types. The control unit adjusts the drive current for each LED based on the detected paper color, ensuring optimal light intensity for each paper type. This resolves the contradiction by avoiding excessive light intensity for high-reflectance papers while maintaining sufficient power for low-reflectance papers, thereby reducing overall power consumption.
Solution Approach 2:
The system dynamically adjusts light source selection and intensity based on real-time paper color detection. The control unit changes which LEDs are activated and at what intensity levels according to the paper type identified. This dynamic adaptation resolves the contradiction between maintaining high output power and reducing power consumption by optimizing light emission for each specific paper type.
3Adaptability or versatility
If multiple light sources are used to handle various paper colors, then detection capability across different paper types is improved, but device complexity increases
Solution Approach 1:
The patent implements preliminary action by pre-classifying paper colors into specific categories (white, yellow, blue, green, red, black) and pre-configuring optimal LED combinations for each category. The control unit has predetermined control signals for each paper type, eliminating the need for complex real-time wavelength optimization. This resolves the contradiction by maintaining high adaptability through simple classification-based control.
Solution Approach 2:
The system achieves universality by using a single sensor device with multiple LEDs that can handle all paper types through wavelength selection. The same sensor structure with red, green, blue, and infrared LEDs serves multiple functions by detecting different paper colors and adjusting light intensity accordingly. This resolves the contradiction by providing versatile paper type handling without proportionally increasing device complexity.
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
The solution effectively reduces power consumption while maintaining high detection accuracy for different paper types, enabling precise edge position detection and improved image formation without deteriorating performance.
Implementation Method 1
The light emitting device is configured to irradiate a conveyed object with linear light along a width direction of the conveyed object... The detecting device is configured to detect, at a plurality of positions in the width direction of the conveyed object, intensity of reflected light of light emitted by the light emitting device
Data Source
AI summary
An edge position detecting apparatus includes a light emitting device, a detecting device, and a calculating circuit. The light emitting device includes a plurality of light sources with different emission wavelengths. The light emitting device irradiates a conveyed object with linear light along a width direction of the conveyed object, the width direction being perpendicular to a conveying direction of the conveyed object. The detecting device detects, at a plurality of positions in the width direction of the conveyed object, intensity of reflected light of light emitted by the light emitting device. The calculating circuit calculates, based on a detection result of the detecting device, a position of an edge of the conveyed object in the width direction.