Optical Sensor End Position Detection with Multi-Threshold Verification
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Solution Overview
Problem
Existing image forming apparatuses face challenges in accurately detecting the end position of a printing medium due to frame lines, dust, or noise superimposed on the detected signal, leading to erroneous detection.
Innovation Solution
A detection device that includes a detection unit to identify changes in light intensity detected by an optical sensor, a candidate setting unit to set potential end positions based on threshold levels and delay times, and a confirmation unit to verify the end position by checking the detection level at a distance from the candidate position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single threshold level is used to detect end position changes, then the detection process is simple and fast, but erroneous detection occurs due to frame lines, dust, or noise
Solution Approach 1:
The patent applies parameter changes by using multiple threshold levels (first threshold level and second threshold level) instead of a single threshold. The detection unit compares the detection level with the first threshold to identify potential end positions, then the confirmation unit verifies these positions by comparing with the second threshold. This multi-parameter approach resolves the contradiction by improving detection accuracy through additional threshold comparisons while maintaining a relatively simple detection process structure.
2Reliability
If preliminary scanning is performed to detect end positions, then the existing region can be detected, but erroneous detection occurs when frame lines or dust are present
Solution Approach 1:
The patent applies preliminary action by performing a preliminary scan to identify potential end position candidates, then conducting a confirmation step to verify these candidates. The detection unit first performs preliminary detection to find positions where the detection level changes, sets these as candidate positions, and then the confirmation unit performs additional verification. This two-stage approach improves reliability by filtering out false positives from frame lines or dust while keeping the time loss acceptable through efficient candidate filtering.
3Measurement precision
If multiple threshold levels and confirmation steps are added to reduce erroneous detection, then detection accuracy improves, but the detection process becomes more complex
Solution Approach 1:
The patent applies segmentation by dividing the detection process into distinct functional units: the detection unit that identifies candidate positions using the first threshold, and the confirmation unit that verifies these candidates using the second threshold. This segmentation allows each unit to have a specific, simplified function while the overall system achieves high precision through their coordinated operation, resolving the contradiction between precision and 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 erroneous detection of end positions by using multiple threshold levels and delay times to confirm the accuracy of the detected end position, even in the presence of frame lines or noise.
Implementation Method 1
an optical sensor that scans the printing medium or the holding member in a scanning direction... by comparing the detection level with a first threshold level
Data Source
AI summary
A detection device includes: a detection unit that detects a change in detection level corresponding to an intensity of light detected by an optical sensor by comparing the detection level with a first threshold level; a candidate setting unit that sets a position of the optical sensor at a time relative to the time of detection of the change as a candidate for the end position if the detection level is between a second threshold level and a level corresponding to the holding member, as a delay time has elapsed in scanning in the scanning direction since the detection of the change; and a confirmation unit that confirms the candidate as the end position if the detection level is between a third threshold level and the level corresponding to the holding member at a position away from the candidate position by more than a threshold distance in the scanning direction.