Scanner Dust Detection and Position Adjustment
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Solution Overview
Problem
Existing scanners face issues with dust accumulation on the platen, leading to abnormal images due to the reader unintentionally moving back to the dust position during document scanning, causing black streaks and image quality degradation.
Innovation Solution
The image reading apparatus employs a controller to detect dust using a reference plate, store the dust position, and adjust the reading position by a predetermined range to avoid the dust, ensuring accurate and dust-free scanning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the reader is moved to a next reading position to avoid dust after dust detection, then image quality is improved, but reading start is delayed
Solution Approach 1:
The system performs dust detection by reading a reference plate before actual document reading starts. The dust position is detected and stored in advance, allowing the reader to be positioned at a dust-free location before reading begins, thus avoiding delays during the reading process itself
2Reliability
If the image reader is moved from standby position to a reading position avoiding stored dust position, then dust avoidance is improved, but movement error increases causing unintentional dust reading
Solution Approach 1:
The system performs dust detection by reading a reference plate before actual document reading starts. The dust position is detected and stored in advance, allowing the reader to be positioned at a dust-free location before reading begins, thus avoiding delays during the reading process itself
Solution Approach 2:
The system adds a spatial buffer zone around the detected dust position, extending the avoidance range beyond the exact dust coordinates. This dimensional expansion in the positioning space ensures that even with movement errors, the reader remains outside the dust-affected area
3Manufacturing precision
If dust detection is performed at reading position, then reading position accuracy is maintained, but dust detection capability is reduced
Solution Approach 1:
The system separates dust detection from document reading by using a dedicated reference plate reading process. The reference plate is read at a predetermined position before actual reading, allowing dust detection to be performed independently without affecting the accuracy of the reading position for actual documents
Data Source
AI summary
An image reading apparatus includes a document feeder; a platen; an image reader configured to read the document, fed by the document feeder, through the platen; a memory; and a controller. The controller causes the image reader to read a reference plate at a predetermined reading position to generate read data, and detecting whether the read data has an abnormality; when the read data has the abnormality, stores a detection position; sets a reading position of the image reader in the sub-scanning direction to a set position spaced by a predetermined range or more from the detection position; when instruction to start reading is received, moves the image reader under standby at a standby position to arrange the image reader at the set position; and reads the document, fed by the document feeder, by the image reader.