Dual Scanner Image Reading Device with Mark-Based Misregistration Compensation
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Solution Overview
Problem
Conventional image forming systems face productivity losses and increased costs due to misregistration issues between scanners when reading front and back images on a sheet, requiring complex mechanical adjustments and frequent monitoring to account for environmental factors.
Innovation Solution
An image reading device with a first and second scanner, a position adjusting unit, and a monitoring unit that uses a mark on the sheet to adjust and monitor front and back positions, allowing for accurate detection of misregistration without mechanical adjustments, thus reducing costs and improving efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If one scanner is used to read both front and back images, then device complexity is reduced, but productivity decreases due to requiring double conveyance time
Solution Approach 1:
The patent divides the scanning function into two separate scanners - one dedicated to reading the front surface and another to reading the back surface. This segmentation allows both surfaces to be read simultaneously during a single conveyance, eliminating the need for double conveyance and improving productivity while maintaining simple device architecture.
2Productivity
If two scanners are used to read front and back images simultaneously, then productivity improves, but manufacturing precision deteriorates due to machine difference causing misregistration
Solution Approach 1:
The patent introduces a reference mark as an intermediary element that both scanners read. This reference mark serves as a common reference point, allowing the system to calculate and compensate for machine differences between the two scanners, thereby maintaining high position accuracy despite using two separate scanning devices.
Solution Approach 2:
The patent dynamically adjusts the reading positions of the two scanners based on the detected position of the reference mark. By changing the reading position parameters according to the actual mark location, the system compensates for machine differences and environmental variations, maintaining accurate front-back image registration.
3Manufacturing precision
If mechanical adjustment is performed to correct machine difference between scanners, then position accuracy improves, but device complexity and cost increase
Solution Approach 1:
The patent replaces mechanical adjustment mechanisms with a software-based compensation system. Instead of using mechanical components to physically adjust scanner positions, the system uses computational methods to calculate and correct for machine differences based on reference mark detection, thereby maintaining high accuracy without adding mechanical complexity.
Solution Approach 2:
The system performs self-adjustment by automatically detecting the reference mark position and calculating the necessary compensation for machine differences. This self-service approach eliminates the need for manual mechanical adjustment while maintaining accurate registration, reducing both device complexity and operational overhead.
4Reliability
If frequent monitoring is performed to detect misregistration, then reliability improves, but productivity decreases due to additional conveyance operations
Solution Approach 1:
The patent performs preliminary detection of the reference mark position during the main conveyance operation. By detecting the mark position as part of the primary scanning process rather than requiring separate monitoring conveyances, the system achieves reliable misregistration detection without sacrificing productivity.
Solution Approach 2:
The reference mark serves multiple functions: it acts as a positioning reference for the scanners and simultaneously serves as a monitoring target for detecting misregistration. This multi-functionality allows the system to perform both reading and monitoring during a single conveyance, improving reliability without reducing productivity.
Data Source
AI summary
An image reading device having a mark formed on front and back of a sheet by an image forming device, and including a first scanner which reads the mark and a second scanner provided at a downstream side of the first scanner and which reads the mark, includes: a position adjusting unit configured to adjust front and back positions of the mark on the basis of a print position of the mark read by at least one of the first scanner and the second scanner; and a monitoring unit configured to monitor front and back misregistration of the mark on the basis of the front and back positions of the mark adjusted by the position adjusting unit.