Duplex Image Reader Counter Reset for Scan Alignment
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Solution Overview
Problem
Conventional image-readers experience offset in the subscanning direction between the reading positions of the first and second image-reading units due to accumulated differences in clock cycle counts, leading to inconsistent image capture from both surfaces of a document.
Innovation Solution
The implementation of a first and second counter system that resets both count values simultaneously when a prescribed value is reached, ensuring synchronized clock signals for both image-reading units to maintain alignment and prevent offset during the scanning process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If independent clock signals are used for the first and second image-reading units, then each unit can operate autonomously, but accumulated clock cycle differences cause offset in the subscanning direction between reading positions
Solution Approach 1:
The patent introduces a feedback mechanism where the control unit monitors the count values from both counters and dynamically adjusts the trigger signals to compensate for accumulated differences. This ensures that despite independent clock operations, the reading positions remain aligned by continuously correcting for drift through feedback control.
Solution Approach 2:
The patent changes the parameter of trigger signal timing by adjusting the second trigger signal's timing relative to the first trigger signal. The control unit modifies the count value thresholds or timing offsets to compensate for clock cycle differences, thereby maintaining synchronized reading positions across both image-reading units.
2Loss of time
If clock cycle counts are compared with reference values to reduce reading time differences, then reading time synchronization improves, but accumulated differences still generate offset over time
Solution Approach 1:
The patent applies preliminary action by pre-adjusting the trigger signal timing and count value thresholds before the reading process begins. The control unit sets up compensatory offsets in advance to counteract expected accumulated differences, ensuring that reading positions remain aligned throughout the document scanning process without requiring continuous real-time correction.
Data Source
AI summary
In an image-reader, the first counter is configured to count a first count value based on a first clock. The second counter is configured to count a second count value based on a second clock. The first reading unit is configured to read a first surface of a document sheet based on the first count value. The second reading unit is configured to read a second surface of the document sheet based on the second count value. The second surface is opposite surface of the first surface. When the first count value reaches a prescribed first value, both the first counter value and the second count value are reset.