Image Reader Crosstalk Reduction via Differential Signal Segmentation
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Solution Overview
Problem
Image readers with two separate units for reading both sides of a document sheet often experience signal interference, known as crosstalk, when a single processor processes signals from both units.
Innovation Solution
Implementing a differential transmission method for the digital signal from the second image reading unit and processing both analog and digital signals from the first and second units separately on a control board to reduce signal interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single processor processes signals from both image reading units, then device complexity is reduced, but signal interference (crosstalk) occurs between the signals
Solution Approach 1:
The patent divides the signal processing function into two separate processors: one dedicated to processing signals from the first image reading unit and another for the second image reading unit. This segmentation isolates the signal processing paths, preventing crosstalk between the analog signal from the first unit and the digital signal from the second unit, while maintaining relatively simple device architecture through functional specialization.
2Productivity
If two image reading units are used to read both sides of a document sheet in parallel, then reading speed is enhanced, but crosstalk between signals increases
Solution Approach 1:
The patent implements separate processing paths for the two image reading units by assigning different processor types: an analog processor for the first unit and a digital processor for the second unit. This segmentation of processing functions eliminates signal interference while preserving the parallel reading capability that enhances productivity.
Solution Approach 2:
The patent introduces separate processing circuits as intermediary elements between each image reading unit and the control system. The first processing circuit handles analog signals from the first reading unit, while the second processing circuit handles digital signals from the second reading unit. These intermediary processing circuits act as buffers that prevent direct signal interference while enabling parallel operation.
3Device complexity
If analog signal transmission is used for both image reading units, then signal processing is simplified, but signal interference and noise increase
Solution Approach 1:
The patent applies different signal transmission qualities to different parts of the system based on their specific requirements. The first image reading unit uses analog signal transmission with dedicated analog processing, while the second image reading unit uses digital signal transmission with dedicated digital processing. This local differentiation of signal types optimizes each path for its specific function, reducing overall noise and interference.
Data Source
AI summary
An image reader is provided, which includes a first image reading unit configured to read an image on a first side of a first document sheet being conveyed on a feeding path, and output an analog signal corresponding to the read image of the first side, a second image reading unit configured to read an image on a second side opposite to the first side of the first document sheet being conveyed on the feeding path, and output a digital signal corresponding to the read image of the second side in a differential transmission method, and a control board configured to process the analog signal output from the first reading unit and the digital signal output from the second image reading unit.