Image Reading Device Correction Unit Timing
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Solution Overview
Problem
Conventional image reading devices require frequent reciprocation between the read and home positions to update light intensity correction data, leading to inefficiencies, especially with fluorescent lamps where light intensity variations are significant within the image scanning range, resulting in inadequate correction data updates.
Innovation Solution
An image reading device with a light source, reading unit, correction unit, and illumination target switch, allowing for the determination and update of correction data by switching between a read position and a reference position based on image data conditions, reducing the need for frequent position switching and improving timing accuracy of data updates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the reading unit reciprocates frequently between read position and home position to update correction data, then the image data correction accuracy is improved, but the reading time increases
Solution Approach 1:
The patent stores correction data in advance in a correction data storage unit. Instead of updating correction data by reciprocating to the home position during each reading operation, the system performs correction data updates preliminarily and stores them for later use. This allows the reading unit to directly use pre-stored correction data during document reading, eliminating the need for frequent reciprocation and reducing reading time while maintaining correction accuracy.
2Loss of time
If correction data is updated using a white reference plate located outside the image scanning range, then the reading operation time is reduced, but the correction data accuracy deteriorates
Solution Approach 1:
The patent places the white reference plate at a position within or overlapping with the image scanning range (read position) rather than outside it. This allows the reading unit to read the white reference plate using the same optical path and sensor area that will be used for document reading. Consequently, the correction data accurately reflects the light intensity distribution and sensor characteristics in the actual reading area, improving correction accuracy while still enabling efficient updates without full reciprocation.
3Measurement precision
If the reading unit returns to home position after each document reading to update light amount distribution data, then the correction accuracy is improved, but the productivity decreases
Solution Approach 1:
The system performs correction data updates preliminarily and stores the data in advance. The reading unit uses pre-stored correction data during document reading operations without returning to the home position. This preliminary update approach maintains correction accuracy while significantly improving reading efficiency by eliminating post-reading reciprocation.
Solution Approach 2:
The correction data storage unit automatically stores correction data for future use. The system serves itself by having the correction data readily available in storage, eliminating the need for the reading unit to repeatedly return to the home position to obtain fresh correction data. This self-service mechanism maintains accuracy while improving productivity.
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 configuration enables timely and accurate updating of correction data, reducing the time required for document reading operations and maintaining image quality by addressing light intensity variations within the image scanning range.
Implementation Method 1
a light source (22a)
Implementation Method 2
read light reflected from the document through an image pick-up device (e.g., a CCD; Charge Coupled Device) converting the received light into a voltage value
Implementation Method 3
a reflector which reflects, toward the reading unit, the light emitted to the read position by the light source
Data Source
AI summary
An image reading device includes a light source, a reading unit to convert received light to image data, a correction unit to correct the image data based on correction data, a storing unit storing the correction data, an illumination target switch unit to switch an illumination target between a read position and a reference position, a reflector reflecting light, a judgment unit to judge whether the image data outputted by the reading unit at the read position satisfies a predetermined condition, a correction data determination unit to determine the correction data in response to a fact that the illumination target of the light source is switched to the reference position, and a correction data update unit to store the correction data in the correction data storing unit. The illumination target switch unit switches the illumination target to the reference position if the image data satisfies the predetermined condition.