Document Floating Distance Detection for Image Density Uniformity
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Solution Overview
Problem
The sheet-through type image reading apparatuses face challenges in maintaining uniform image density due to varying floating amounts of documents above the platen glass, leading to density unevenness and image quality issues.
Innovation Solution
An image reading apparatus with an automatic document feeding unit, a reading unit, a converting unit, and a detecting unit that adjusts image parameters based on the detected floating amount, using a table or input adjustments to correct for differences in document type and thickness, ensuring high image quality and precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a document floats above the platen glass to prevent image streaks and stains, then the platen glass is protected from foreign substances, but the floating amount varies depending on paper type and thickness, causing density unevenness in read images
Solution Approach 1:
The floating amount detecting unit measures the document's floating amount before the reading process, and the setting unit pre-adjusts image parameters based on the detected floating amount. This preliminary detection and adjustment prevents density unevenness from occurring during the actual reading process.
Solution Approach 2:
The system changes image parameters (such as illumination intensity, reading speed, or focal position) based on the detected floating amount. By dynamically adjusting these parameters according to the actual floating condition, the system compensates for the varying distances between the document and platen glass, maintaining uniform image density.
2Manufacturing precision
If image parameters are adjusted based on detected floating amount to correct density unevenness, then image quality is improved, but additional detecting and setting units are required, increasing device complexity
Solution Approach 1:
The floating amount detecting unit can be integrated with existing sensing mechanisms in the image reading apparatus, and the setting unit can utilize the same control system that adjusts other reading parameters. This multi-functionality approach reduces the need for completely separate detection and control systems.
Solution Approach 2:
The system establishes a feedback loop where the floating amount detecting unit continuously monitors document position, and the setting unit automatically adjusts image parameters based on this feedback. This closed-loop control eliminates the need for manual intervention and complex mechanical adjustment 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
The solution effectively reduces density unevenness and maintains high image quality by adjusting parameters based on detected floating amounts, allowing for precise image correction and customization, while preventing stains on the platen glass.
Implementation Method 1
by irradiating a portion on the document at the reading location using a light source disposed below the platen glass member, and by receiving reflected light from the portion on the document
Data Source
AI summary
An image reading apparatus is disclosed. The image reading apparatus includes an automatic document feeding unit that transports a document in a predetermined direction while the document floats above a platen glass member and a light source disposed below the platen glass member that irradiates a portion on the document at a predetermined reading location such that reflected light from the portion on the document is converted into image data and a floating distance between the document and the platen glass member is detected to set a value of an image parameter for correcting the image data for the document, based on the detected floating distance between the document and the platen glass member.