Image Reading Device Conveyance Path Adjustment for Shading Correction
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Solution Overview
Problem
Image forming apparatuses face challenges in capturing high-accurate images across various recording medium thicknesses due to complex adjustment mechanisms and productivity losses during shading correction, especially when handling continuous recording media.
Innovation Solution
An image reading device with a conveyance path moving mechanism that adjusts the distance between the imaging device and the recording medium, allowing for precise positioning of the medium's surface and enabling simple, efficient shading correction without medium removal or complex adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a large clearance is provided between the recording medium and the scanner glass to avoid contact, then the recording medium is protected from damage, but the focal range extension becomes more difficult and the adjustment mechanism becomes complex
Solution Approach 1:
The patent employs a movable guide roller mechanism that can dynamically adjust its position between the imaging device and the discharge tray. The guide roller moves along a guide groove to change the conveyance path length, thereby adjusting the distance between the recording medium and the scanner glass. This dynamic adjustment allows the system to maintain appropriate clearance for medium protection while achieving the required focal range for different medium thicknesses without complex mechanical adjustments.
2Measurement precision
If the continuous recording medium is removed from the imaging area to place the reference color member, then shading correction can be performed, but the productivity decreases due to medium removal and remounting
Solution Approach 1:
The patent uses a movable guide roller mechanism that can temporarily retract the continuous recording medium from the imaging area during shading correction. The guide roller moves along a guide groove to shorten the conveyance path, allowing the recording medium to be pulled back and creating space for the reference color member. After shading correction is complete, the guide roller returns to its original position and the recording medium continues conveying normally. This dynamic adjustment enables shading correction without permanent medium removal, thereby maintaining productivity.
Solution Approach 2:
The system performs shading correction at predetermined intervals during the printing process rather than requiring complete medium removal. The movable guide roller enables quick temporary retraction of the medium for reference color member placement, allowing shading correction to be performed preliminarily and periodically without interrupting the overall printing workflow, thus maintaining high productivity.
3Measurement precision
If the lens is moved to adjust focus for different recording medium thicknesses, then the imaging accuracy is improved, but the adjustment mechanism becomes complex and requires exact adjustment
Solution Approach 1:
Instead of moving the lens for focus adjustment, the patent employs a movable guide roller that dynamically adjusts the conveyance path length. By changing the path length, the system adjusts the distance between the recording medium and the scanner glass, thereby achieving focus adjustment for different medium thicknesses. This approach replaces complex lens movement mechanisms with a simpler guide roller translation system, reducing overall mechanism complexity while maintaining imaging accuracy.
Solution Approach 2:
The patent introduces a movable guide roller as an intermediary element between the recording medium and the scanner. This guide roller mediates the distance adjustment by translating along a guide groove, thereby changing the conveyance path length and adjusting the focal distance. This intermediary mechanism simplifies the focus adjustment process compared to direct lens movement, as the guide roller provides a mechanical advantage and easier control for distance adjustment.
Data Source
AI summary
An image reading device includes: a conveyer, and an imaging device that reads optical information on a surface of a sheet-like member being conveyed by the conveyer, in an imaging area of a predetermined range in a conveyance direction. The conveyer includes a conveyance path moving mechanism that moves a conveyance path in the imaging area so that a distance from the imaging device changes and adjusts a position of the surface of the sheet-like member to a position at a predetermined distance from the imaging device. An image forming apparatus includes: the image reading device; and an image forming section that uses the sheet-like member being conveyed by the conveyer as a recording medium and forms an image on a surface of the recording medium.