Image Reading Apparatus Thick Paper Multifeeding Detection
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Solution Overview
Problem
Existing image reading apparatuses face issues with erroneous detection of multifeeding due to thick paper, leading to unnecessary interruptions and complex operations, as they struggle to differentiate between thick paper and multiple documents using ultrasonic wave sensors and existing thickness detection methods.
Innovation Solution
An image reading apparatus with a control unit that reads the shadow generated at a background plate and compares its pixel value with a predetermined threshold to determine document thickness, thereby avoiding false multifeeding detection when thick paper is present, and disabling multifeeding detection when the paper is determined to be thick.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If ultrasonic wave sensor is used to detect multifeeding, then multifeeding detection capability is improved, but thick paper causes erroneous detection as multifeeding
Solution Approach 1:
The patent introduces a shadow detection mechanism as an intermediary to distinguish between thick paper and actual multifeeding. The shadow detection unit captures the shadow of the document on the background plate, and the control unit analyzes shadow intensity to differentiate thick paper (which casts a visible shadow) from multiple thin papers (which do not cast significant shadows). This intermediary measurement resolves the ambiguity caused by ultrasonic wave attenuation alone.
Solution Approach 2:
The patent changes the detection parameter from solely ultrasonic wave transmission attenuation to a combination of ultrasonic wave attenuation and shadow intensity. By adding the shadow intensity parameter, the system can differentiate between thick paper (high shadow intensity) and multifeeding (low shadow intensity but high ultrasonic attenuation), thereby resolving the erroneous detection problem.
2Measurement precision
If shape recognition method is used to detect thick paper, then thick paper detection capability is improved, but reading timing is delayed as entire document must be read
Solution Approach 1:
The patent performs shadow detection during the initial document reading phase, before complete document processing is required. The shadow of the document on the background plate is captured and analyzed in real-time as the document passes through the reading unit, allowing thick paper detection to occur in advance of complete document reading and processing.
Solution Approach 2:
The patent extracts the shadow information from the background plate separately from the main document reading process. By detecting the shadow intensity on the background plate independently, the system can determine document thickness without needing to complete the entire document reading and shape recognition process, thus avoiding time delays.
3Measurement precision
If shadow detection is performed after complete reading, then thick paper detection accuracy is improved, but multifeeding detection timing is too late to prevent erroneous interruption
Solution Approach 1:
The patent performs shadow detection during the initial document reading phase, before complete document processing is required. The shadow of the document on the background plate is captured and analyzed in real-time as the document passes through the reading unit, allowing thick paper detection to occur in advance of complete document reading and processing.
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 approach prevents erroneous multifeeding detection, allowing for correct document reading and reducing user intervention by accurately distinguishing thick paper from multiple documents, thus enhancing the reliability and efficiency of the image reading process.
Implementation Method 1
When the ultrasonic wave sensor is installed on a transportation path of the document, a transmission attenuation amount of ultrasonic waves at the time when the plurality of the documents pass becomes greater than a transmission attenuation amount of the ultrasonic waves when a single document passes
Implementation Method 2
the control unit causes the reading unit to read a shadow, generated at the background plate, of the document
Data Source
AI summary
A reading unit is configured to capture an image of a shadow generated at a leading end of a document, and a control unit is configured to estimate a thickness of the document based on a pixel value of the shadow. A multifeeding error is displayed on a display unit when it is determined as thin paper in a thick paper determination. The control unit turns multifeeding detection to OFF and stands by until a feeding is completed, and upon completion, returns the multifeeding detection to ON.