Optical Sensor for Image Density and Color Misregistration Detection
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Solution Overview
Problem
Existing image forming apparatuses face challenges in accurately detecting color misregistration and image density due to variations in temperature, humidity, and operating time, which affect the quality of mixed color images, and the size of optical sensors limits their ability to receive reflected light at ideal angles.
Innovation Solution
The apparatus incorporates an optical sensor with two light emitting elements and two light receiving elements bonded to a substrate, allowing for reduced size and improved accuracy in detecting specularly and diffusely reflected light, enabling precise color misregistration and image density corrections by forming specific pattern images and test images on an intermediate transfer belt.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If bullet light emitting elements and bullet light receiving elements are soldered on a substrate to form an optical sensor, then the optical sensor can detect specularly reflected light and diffused reflected light, but the size of the optical sensor cannot be reduced
Solution Approach 1:
The optical sensor is divided into multiple functional components: a light emitting element, a light receiving element, and a gloss detecting element. Each element is positioned at specific angles to detect different types of reflected light (specular and diffused) separately, allowing for precise detection while maintaining a compact integrated structure.
Solution Approach 2:
The patent utilizes angular positioning in three-dimensional space to differentiate detection functions. The light receiving element is positioned at a first angle to detect specularly reflected light, while the gloss detecting element is positioned at a second angle to detect diffused reflected light, enabling functional differentiation without increasing planar footprint.
2Adaptability or versatility
If light receiving elements are arranged to detect both color misregistration and image density, then one sensor can perform multiple functions, but the arrangement is restricted and ideal light receiving angles cannot be achieved
Solution Approach 1:
The detection functions are segmented into separate elements: a light receiving element for detecting specularly reflected light (used for color misregistration detection) and a gloss detecting element for detecting diffused reflected light (used for image density detection). This segmentation allows each element to be positioned at its optimal angle for its specific function.
Solution Approach 2:
Different parts of the optical sensor have specialized functions optimized for their specific detection tasks. The light receiving element is positioned to optimally receive specularly reflected light for color misregistration detection, while the gloss detecting element is positioned to optimally receive diffused reflected light for image density detection.
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, allowing for effective corrections and maintaining image quality despite environmental and operational variations, while also reducing the size and cost of the optical sensor.
Implementation Method 1
The first PD (711) is arranged at a position at which an optical axis of specularly reflected light of light emitted from the second LED (702)... is received
Implementation Method 2
The second PD (712) is arranged at a position at which an optical axis of diffused reflected light of light emitted from the second LED (702)... is received
Data Source
Figure 1~2
Figure 3A~3B
Figure 4~5
AI summary
An image forming apparatus (100) includes an optical sensor (7) configured to detect an image formed on an intermediate transfer belt (5). The optical sensor (7) includes a first LED (701), a second LED (702), a first PD (711), and a second PD (712). The first LED (701) and the second LED (702) irradiate an optical-axis center point(P) of an intermediate transfer belt (5). The first PD (711) is arranged at a position at which an optical axis of specularly reflected light of light emitted from the second LED (702) and an optical axis along which specularly reflected light of light emitted from the first LED (701) is received form an angle Ψ. The second PD (712) is arranged at a position at which the optical axis of the specularly reflected light of the light emitted from the second LED (702) and an optical axis along which diffused reflected light of the light emitted from the second LED (702) is received.