Image Reading Device Background Member Reflectance Correction
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Solution Overview
Problem
Existing image reading devices struggle to maintain consistent reading levels across the width of a recording medium due to variations in light intensity, particularly affecting the center portion, which is not adequately addressed by current correction methods that focus on the end portions.
Innovation Solution
The image reading device incorporates a background member with a center reference portion of higher reflectance than the end portions, allowing for continuous correction of reading levels across the width by using the white reference plate and conveyance rollers with varying light reflectance to adjust gain and maintain consistent illumination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a white reference plate is used to correct reading levels, then the reading level consistency is improved, but the correction is insufficient for the center portion of the recording medium
Solution Approach 1:
The background member is divided into multiple regions with different reflectances: a center portion with higher reflectance and end portions with lower reflectance. This segmentation allows each region to correct reading levels for corresponding areas of the recording medium, solving the problem of insufficient center portion correction while maintaining overall reading consistency.
Solution Approach 2:
Different portions of the background member are assigned different reflectance properties tailored to their specific functions. The center portion has higher reflectance to compensate for light intensity decrease and illuminate the center area adequately, while end portions have lower reflectance to match the natural light distribution at edges, achieving localized optimization of reading level correction.
2Productivity
If the illumination unit operates continuously, then reading speed is maintained, but light intensity decreases over time causing reading level variation
Solution Approach 1:
The image reading device reads the background member periodically to detect variations in light intensity caused by illumination unit degradation. Based on this feedback, the device calculates correction values and adjusts reading levels dynamically, compensating for light intensity decrease over time while maintaining consistent reading speed and accuracy.
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 solution effectively corrects reading levels on both the center and end portions of the recording medium, ensuring consistent image reading without increasing power consumption or reducing reading speed, even as light intensity decreases over time.
Implementation Method 1
The illumination unit emits light to a recording medium having an image thereon
Implementation Method 2
The reference portion has a higher reflectance than an end portion of the facing surface in the width direction
Implementation Method 3
The reader receives a reflection from the recording medium to read the image
Data Source
AI summary
An image reading device includes a background member, an illumination unit opposed to the background member, and a reader. The illumination unit emits light to a recording medium having an image thereon. The reader receives a reflection from the recording medium to read the image. The background member has a facing surface that faces the recording medium. The facing surface includes a reference portion on a center portion in a width direction of the background member. The reference portion has a higher reflectance than an end portion of the facing surface in the width direction.