Optical Sensor for Image Density Detection
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Solution Overview
Problem
Existing optical sensors in electrophotographic image forming apparatuses face challenges in accurately detecting color misregistration and image density due to restricted arrangements of light receiving elements, leading to potential inaccuracies in measurement, and are difficult to miniaturize while accommodating different measurement objects.
Innovation Solution
The optical sensor includes a substrate with a first light emitting element for specularly reflected light and a second light emitting element for scattered reflected light, with light receiving elements of varying surface areas and orientations to optimize detection accuracy and size reduction, allowing for precise detection of color misregistration and image density using both specularly and scattered reflected light methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If bullet light emitting elements and bullet light receiving elements are soldered on a substrate, then the optical sensor can detect both specularly reflected light and scattered reflected light, but the size of the optical sensor cannot be reduced
Solution Approach 1:
The patent combines multiple light receiving elements (first light receiving element for specularly reflected light and second light receiving element for scattered reflected light) and light emitting elements on a single substrate, integrating multiple detection functions into one compact sensor unit, thereby reducing overall sensor size while maintaining versatile detection capability
Solution Approach 2:
The optical sensor is designed with multiple light receiving elements that can detect both specularly reflected light and scattered reflected light using the same sensor structure, enabling the sensor to perform multiple detection functions (color misregistration detection and image density detection) without requiring separate sensors
2Adaptability or versatility
If light receiving elements are arranged to detect both color misregistration and image density, then measurement capabilities are improved, but the arrangement is restricted and detection accuracy cannot be optimized
Solution Approach 1:
The patent assigns different light receiving elements with specific characteristics to different detection tasks: the first light receiving element is optimized for detecting specularly reflected light (color misregistration), while the second light receiving element is optimized for detecting scattered reflected light (image density), allowing each element to operate at its optimal performance point
Solution Approach 2:
The optical sensor is segmented into multiple specialized light receiving elements, each responsible for detecting specific types of reflected light for different measurement purposes, rather than using a single general-purpose receiver, thereby improving overall measurement precision
3Device complexity
If the optical sensor uses a single light receiving element for both color misregistration and image density detection, then device complexity is reduced, but detection accuracy for both parameters deteriorates
Solution Approach 1:
The patent merges multiple light receiving elements and light emitting elements into a single integrated optical sensor module on one substrate, maintaining compact structure and manageable complexity while achieving high detection accuracy through the collaborative work of multiple specialized elements
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 enables high-accuracy detection of color misregistration and image density, reduces the size of the optical sensor, and allows for flexible arrangement of light emitting and receiving elements, improving measurement capabilities without increasing the sensor's size.
Implementation Method 1
a first light receiving element, which is provided on the substrate, and is configured to receive specularly reflected light from the detection image
Implementation Method 2
a second light receiving element, which is provided on the substrate, and is configured to receive scattered reflected light from the detection image
Data Source
AI summary
An image forming apparatus includes an optical sensor configured to detect an image formed on an intermediate transfer belt. The optical sensor includes a first light emitting diode (LED), a second LED, a first photodiode (PD), and a second PD on a substrate. The first PD is arranged at a position at which specularly reflected light of light emitted from the first LED can be received, and scattered reflected light of light emitted from the second LED can be received. The second PD is arranged at a position at which scattered reflected light of light emitted from the second LED can be received. A light receiving surface of the first PD and a light receiving surface of the second PD are formed at different angles. The light receiving surface of the first PD has an area that is smaller than an area of the light receiving surface of the second PD.