Dynamic Skew Threshold for Image Scanner Feeding
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Solution Overview
Problem
Existing image reading apparatuses incorrectly determine that documents with different widths are bound when they are not, due to skew issues caused by fixed side regulating plates, leading to erroneous suspension of feeding operations.
Innovation Solution
An image reading apparatus with a control unit that adjusts the skew threshold based on whether documents of different widths are detected, setting a higher threshold for mixed-width documents to prevent false positives, and using sensors to detect the leading edge skew and suspend feeding operations if the skew exceeds this threshold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a fixed skew threshold is used for all document types, then bound documents can be detected accurately, but documents of different widths cause erroneous detection as bound
Solution Approach 1:
The skew threshold is changed from a fixed value to a dynamic value that adapts based on document width. The control unit adjusts the threshold according to the detected document width, allowing the system to maintain accurate bound document detection while avoiding false positives for narrow documents of different widths.
Solution Approach 2:
The system changes the threshold parameter based on document characteristics. When a document of different width is detected, the control unit modifies the skew threshold value to prevent erroneous detection, thereby resolving the contradiction between measurement precision and reliability.
2Reliability
If the skew threshold is increased to accommodate documents of different widths, then false positives are reduced, but detection accuracy for bound documents decreases
Solution Approach 1:
Rather than using a uniformly high threshold, the system dynamically adjusts the threshold based on document width. This allows the threshold to be high enough to prevent false positives for narrow documents while remaining sensitive enough to detect actual bound documents.
Solution Approach 2:
Different threshold values are applied based on local document characteristics (width). The system tailors the detection criteria to the specific document being processed, allowing optimal detection parameters for each document type rather than using a one-size-fits-all approach.
3Stability of the object's composition
If side regulating plates are fixed for the largest document size, then large documents are regulated properly, but smaller documents experience skew
Solution Approach 1:
The system transitions from static fixed regulating plates to a dynamic detection and adjustment system. The control unit detects document width and adjusts the effective regulation position or threshold accordingly, compensating for the fixed physical position of the regulating plates.
Solution Approach 2:
The system uses feedback from document width detection to adjust detection parameters. The control unit receives information about document width from detection units and uses this feedback to modify the skew threshold, thereby compensating for the lack of physical regulation adjustment.
Data Source
AI summary
An image reading apparatus includes a control unit that is configured to suspend an operation of a separation-feeding unit in a feeding operation when the control unit determines, based on a signal from a leading edge detecting unit, that an inclined amount of the leading edge of a fed document is larger than a setting value. The control unit is also configured to set, when a mixture of different widths is set to the setting unit, the setting value larger in comparison to a case where a mixture of different widths is not set.