Image Sensor Black Correction for High Density Media Edge Detection
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Solution Overview
Problem
Existing position detecting devices in image forming apparatuses face challenges in accurately detecting the edge position of recording media with high density, leading to erroneous detections due to low reflectance, which affects the precision of positional adjustments in the main-scanning direction.
Innovation Solution
A position detecting device that utilizes an image sensor and circuitry for black correction processing, generating black correction data by subtracting dark output values from the output signal, thereby enhancing the detection accuracy of the edge position by isolating the reflected light component and correcting for fixed pattern noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If an optical sensor is used to detect the end portion of a recording medium, then the detection process is simple and fast, but the detection accuracy deteriorates for high density recording media due to low reflectance
Solution Approach 1:
The patent applies preliminary action by performing black correction processing before edge position detection. The circuitry pre-processes the output signal by subtracting black correction data (obtained when no light is incident on the image sensor) to remove fixed pattern noise and dark current effects. This preliminary correction ensures that subsequent edge position detection is not affected by sensor-specific artifacts, thereby improving measurement precision without compromising detection speed
Solution Approach 2:
The patent replaces the conventional optical sensor-based detection system with an image sensor-based system that incorporates digital signal processing. Instead of relying solely on optical reflection thresholds, the system uses an image sensor to capture reflected light patterns and applies black correction processing to the output signals. This substitution enables more accurate detection of edge positions on high density media by removing fixed pattern noise through digital processing
2Measurement precision
If black correction processing is performed using black correction data, then the detection accuracy for high density media is improved, but the processing time and complexity increase
Solution Approach 1:
The patent performs black correction processing as a preliminary step before edge position detection. The circuitry obtains black correction data when no light is incident on the image sensor and stores it for subsequent correction operations. By pre-processing the sensor output to remove fixed pattern noise and dark current effects, the system simplifies the overall detection process and improves measurement precision without significantly increasing device complexity
Solution Approach 2:
The system performs self-correction by using its own output signals to generate black correction data. The image sensor captures dark current and fixed pattern noise characteristics during initialization or calibration phases, and the circuitry automatically subtracts these artifacts from subsequent measurements. This self-service approach eliminates the need for external calibration equipment or complex additional processing components
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 improves the detection accuracy of the edge position for recording media with high density, ensuring precise positional adjustments and reducing erroneous detections, thereby enhancing the overall printing quality and reliability.
Implementation Method 1
an image sensor that reads reflected light of light emitted from a light source onto a medium to be read
Data Source
AI summary
A position detecting device includes an image sensor and circuitry. The image sensor is configured to read reflected light of light emitted from a light source onto a medium to be read. The circuitry is configured to perform black correction processing on an output signal of the image sensor using black correction data of the image sensor and detect a position of the medium from the output signal after the black correction processing.