Sensor Unit Edge Detection Diffuser Illumination
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Solution Overview
Problem
Conventional image forming apparatuses face challenges in accurately detecting the edge position of a recording medium due to luminance unevenness in the illumination device, leading to misdetected sheet width direction end positions, especially when the paper sheet and non-passing area have similar colors or when the illumination device emits uneven light.
Innovation Solution
A sensor unit comprising an edge detection sensor and an illumination device with a diffuser to suppress luminance unevenness, where the illumination device includes a light source and a diffuser that diffuses light to ensure consistent illumination, allowing accurate detection of the recording medium's edge position regardless of paper color or light emission uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the illumination device is disposed to face the edge detection sensor in the sheet conveying path, then the edge detection sensor can receive light directly for detection, but luminance unevenness in the emitted light causes large light intensity differences leading to misdetected sheet width direction end positions
Solution Approach 1:
The patent introduces a light guide as an intermediary component between the illumination device and the edge detection sensor. The light guide receives light from the illumination device and guides it to the sensor, ensuring uniform light distribution and eliminating luminance unevenness that causes detection errors. This mediator component resolves the contradiction by maintaining both direct light reception and uniform illumination.
2Productivity
If the illumination device emits light directly to the edge detection sensor, then detection can be performed, but uneven light emission results in large light intensity differences causing misdetected positions
Solution Approach 1:
The light guide serves as a mediator that maintains the rapid detection capability while improving measurement precision. It transmits light quickly from the illumination device to the sensor without significant delay, preserving detection speed, while simultaneously uniformizing the light distribution to eliminate intensity differences that cause detection errors.
3Device complexity
If conventional illumination devices are used without diffusers, then the device complexity is reduced, but luminance unevenness causes misdetected sheet width direction end positions
Solution Approach 1:
The light guide is a relatively simple intermediary component that can be integrated into the existing illumination device structure without significantly increasing complexity. It effectively uniformizes light distribution to eliminate detection errors, providing a balance between structural simplicity and measurement precision.
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 enables precise detection of the recording medium's edge position, reducing the likelihood of misdetected positions and improving the accuracy of image positioning, thereby enhancing the quality of printed images by minimizing positional deviations.
Implementation Method 1
a diffuser that diffuses light from the light source and suppresses luminance unevenness
Data Source
AI summary
A sensor unit includes an edge detection sensor and an illumination device. The edge detection sensor is disposed in a conveying path of a recording medium and detects a recording medium edge position in a width direction perpendicular to a conveying direction. The illumination device is disposed to face the edge detection sensor in the conveying path and emits light toward the edge detection sensor. The illumination device includes a light source and a diffuser. The light source emits light. The diffuser diffuses the light from the light source and suppresses luminance unevenness.