Image Reading Apparatus Sheet Conveyance Magnification Control
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Solution Overview
Problem
Conventional image reading apparatuses face challenges in maintaining consistent magnification ratios between the recto and verso sides of a sheet due to varying sheet conveying speeds, requiring complex control systems to adjust roller speeds.
Innovation Solution
An image reading apparatus with a sheet tray, separator, and resisting force applicator that conveys sheets in a predetermined direction, using a switchback roller with controlled peripheral velocities to apply convey-resisting force and ensure consistent scanning of both sides, thereby reducing the complexity of the control system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the image reading apparatus uses different sheet conveyer paths for recto and verso reading, then both sides of the sheet can be scanned, but the sheet conveying speeds differ causing different magnification ratios
Solution Approach 1:
The patent applies preliminary anti-action by introducing a resisting force mechanism that actively counteracts the speed difference between recto and verso conveyance paths. The resisting force is applied to the sheet in one of the paths to equalize the conveying speeds, preventing the magnification ratio discrepancy before it affects the final image quality.
Solution Approach 2:
The patent employs parameter changes by dynamically adjusting the conveying speed parameter through controlled resisting force application. By modifying the speed parameter in one conveyer path to match the other, the system maintains consistent magnification ratios while preserving dual-sided reading capability.
2Manufacturing precision
If the image reading apparatus equips a mechanism to detect sheet conveying speeds and adjust roller speeds, then magnification ratio consistency is improved, but the control system becomes complicated
Solution Approach 1:
The patent extracts the complex speed detection and adjustment mechanism from the system by using a simpler resisting force application approach. Instead of equipping sensors and control systems to detect and adjust speeds, the invention applies a mechanical resisting force that passively equalizes speeds through force balance, eliminating the need for complex electronic control.
Solution Approach 2:
The system achieves self-service by using the resisting force mechanism to automatically equalize conveying speeds without external detection or control. The mechanical system self-regulates the speed difference through force application, eliminating the need for external sensors, processors, and control algorithms.
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 effectively restricts the difference in magnification ratios between the two sides of the sheet, ensuring closer alignment of reproduced images without the need for intricate speed control mechanisms.
Implementation Method 1
a separator, which is configured to frictionally pick up the sheet from the sheet tray and convey the picked-up sheet toward an entry side of the image reader unit
Implementation Method 2
a resisting force applier, which is configured to apply convey-resisting force to the sheet, of which first side has been scanned, being returned to the entry side of the image reader unit
Data Source
AI summary
An image reading apparatus to convey a sheet to be scanned to an image reader unit is provided. the image reading apparatus includes a sheet tray, in which the sheet to be scanned is stored, a separator, which frictionally picks up the sheet from the sheet tray and conveys the picked-up sheet toward an entry side of the image reader unit, through which the sheet enters a position above the image reader unit, to have a first side of the sheet scanned by the image reader unit, and a resisting force applier, which applies convey-resisting force to the sheet, of which first side has been scanned, being returned to the entry side of the image reader unit to have a second side of the sheet with the convey resistance scanned by the image reader unit.