Rectangular Hole Calibration for Flatbed Scanner Start Position
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Solution Overview
Problem
In flatbed scanning devices, calibrating the scanning start position using a rectangular hole is challenging due to variations in the position of photoelectric conversion elements, leading to potential loss of pixels and inaccurate scanning results, especially when the hole's side extends in the sub-scanning direction.
Innovation Solution
A scanning device with a rectangular hole on the holder's facing area, where the edges extending along the sub-scanning direction are positioned at the central area of the photoelectric conversion element row, excluding the ends, allowing accurate detection and calibration of the scanning start position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the rectangular hole is used for scanning start position calibration, then the scanning start position can be determined, but pixels may be lost when the hole's side extends in the sub-scanning direction
Solution Approach 1:
The patent applies local quality by positioning the rectangular hole's sides specifically in the central area of the photoelectric conversion element row, excluding the ends. This localized placement ensures that the hole is scanned by photoelectric conversion elements with high detection accuracy, while avoiding areas where pixel loss may occur due to seam effects at the edges of the sensor array.
2Productivity
If multiple photoelectric conversion element chips are arrayed in the main scanning direction, then the required size of photoelectric converter is reduced, but seams between chips create incongruity in scanning results
Solution Approach 1:
The patent uses the rectangular hole as an intermediary reference object that spans across multiple photoelectric conversion element chips. By positioning the hole's sides in the central area of the element row, it creates a consistent reference point that can be detected across chip boundaries, allowing the system to calibrate the scanning start position accurately despite the presence of seams between chips.
3Measurement precision
If the rectangular hole edges are positioned at the central area of photoelectric conversion elements, then scanning start position calibration accuracy is improved, but the configuration becomes more constrained
Solution Approach 1:
The patent applies preliminary action by pre-positioning the rectangular hole in a specific location on the holder, with its sides aligned to the central area of the photoelectric conversion element row. This preliminary configuration is established during holder manufacturing, so that when scanning occurs, the hole automatically serves as an accurate calibration reference without requiring additional adjustment or complex positioning mechanisms.
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 precise determination of the scanning start position, minimizing the impact of seams between photoelectric conversion elements and ensuring focused scanning with high accuracy, even when the hole's edges are scanned under conditions similar to those of the original document.
Implementation Method 1
it is hard to form a shadow of the side by light from the light source of the scanning device
Implementation Method 2
the photoelectric converter including a photoelectric conversion element row, the photoelectric conversion element row including a plurality of photoelectric conversion elements arranged in a main scanning direction
Data Source
AI summary
A scanning device includes a casing holding a original document table. A facing area is provided to the casing, and a rectangular hole is formed on the facing area. The rectangular hole has edges extending along a main scanning direction and edges extending along a sub-scanning direction. The edges extending along the sub-scanning direction are located in a central area of a photoelectric conversion element row of a sensor assembly in the main scanning direction. The sensor assembly scans the rectangular hole and detects a edge extending along the main scanning direction and a edge extending along the sub-scanning direction, thereby determines a scanning start position.