Rocking Optical Unit for Accurate White Reference Data
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Solution Overview
Problem
Existing sheet conveying devices face challenges in acquiring accurate white reference data due to dirt on the reading surface of the white reference member, as they rely on stationary image reading units that cannot effectively avoid dirty areas during shading compensation.
Innovation Solution
A sheet conveying device with a transmission device that rocks the optical unit in the longitudinal direction, allowing the image reading unit to move between an initial position and a position to read a reflectance standard, enabling reading of the reflectance standard away from dirty regions and acquiring proper white reference data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the image reading unit is stationary, then the device structure is simple, but the reading accuracy deteriorates due to dirt on the white reference member
Solution Approach 1:
The optical unit is designed to be movable rather than stationary, allowing it to rock in the widthwise direction to read different locations on the white reference member. This dynamic capability enables the system to avoid dirty areas and acquire accurate white reference data, resolving the contradiction between reading accuracy and structural simplicity.
2Reliability
If the optical unit reads only one location, then the structure is simple, but the reliability deteriorates when that location has dirt
Solution Approach 1:
The transmission device enables the optical unit to dynamically change its reading position by rocking in the widthwise direction. This allows the system to read multiple locations on the white reference member and select clean areas for accurate data acquisition, improving reliability without requiring complex multi-sensor systems.
3Measurement precision
If the image reading unit remains fixed, then the manufacturing cost is low, but the shading compensation accuracy deteriorates
Solution Approach 1:
The optical unit incorporates a rocking mechanism that allows it to move in the widthwise direction during shading compensation. This dynamic movement enables the system to read the white reference member at multiple positions and average the data, significantly improving shading compensation accuracy while maintaining relatively simple device architecture.
Data Source
AI summary
A sheet conveying device includes a drive device, a conveyance device, an optical unit, a white reference member, and a transmission device. The drive device generates a driving force. The conveyance device conveys a sheet by a rotary driving force of the drive device. The optical unit includes an image reading unit that extends in a longitudinal direction thereof along a widthwise direction orthogonal to a direction of conveyance of the sheet, applies light to the sheet, and reads light reflected from the sheet with an image sensor. The white reference member extends in the longitudinal direction of the image reading unit and is read by the image reading unit. The transmission device transmits the driving force generated by the drive device to rock the optical unit in the widthwise direction. The transmission device includes a rocking member that rocks the optical unit in a longitudinal direction thereof.