Elastic Opposing Roller for Card Thickness Variation in Image Reading
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Solution Overview
Problem
Conventional image reading devices face challenges in accurately reading both sides of card-like media with varying thicknesses due to changes in the distance between image sensors and the media, leading to decreased image accuracy and quality.
Innovation Solution
The implementation of a conveyance mechanism with pairs of drive and opposing rollers made of elastic materials, where both rollers deform equally, maintaining a consistent distance between the card-like medium and image sensors, thereby preventing the center of the medium from moving in the thickness direction, and ensuring equal distances for both image sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional conveyance rollers with rigid opposing rollers are used, then the structure is simple and manufacturing is easy, but the distance between image sensors and card-like medium varies with medium thickness, reducing image reading accuracy
Solution Approach 1:
The opposing roller is changed from a rigid structure to an elastic structure, allowing it to deform in response to the card-like medium thickness. This parameter change enables the roller surface to maintain consistent contact pressure and position relative to the medium, ensuring stable image reading distance regardless of medium thickness variations.
Solution Approach 2:
The conveyance mechanism uses composite material construction where the opposing roller is made of elastic material rather than rigid material. This material selection allows the roller to adapt to different medium thicknesses while maintaining structural integrity and consistent performance.
2Measurement precision
If elastic opposing rollers are used to maintain consistent distance, then image reading accuracy improves, but the device structure becomes more complex
Solution Approach 1:
The opposing roller material is changed to elastic material with appropriate hardness and elasticity parameters. This allows the roller to automatically adapt to different card thicknesses through elastic deformation, maintaining consistent contact pressure and position without requiring complex adjustment mechanisms.
Solution Approach 2:
The elastic opposing roller performs self-adjustment through its inherent elasticity, automatically adapting to different card-like medium thicknesses without requiring external control systems or complex mechanical adjustments. The roller's elastic properties enable it to self-regulate the contact pressure and position.
3Adaptability or versatility
If the conveyance mechanism accommodates varying card thicknesses, then versatility improves, but maintaining equal image sensor distances for both sides becomes difficult
Solution Approach 1:
The opposing roller is designed with elastic properties that allow it to deform symmetrically when accommodating cards of different thicknesses. This elastic deformation ensures that both the front and back surfaces of the card maintain equal distances from their respective image sensors, preserving manufacturing precision while accommodating versatility.
Solution Approach 2:
While the overall structure appears symmetric, the elastic opposing roller introduces controlled asymmetry in its deformation behavior based on card thickness, allowing the system to adapt to varying conditions while maintaining symmetric image quality on both sides of the card.
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 ensures accurate reading of both sides of card-like media with different thicknesses by maintaining consistent image sensor distances, preventing image quality differences and reducing the risk of image sensor depth of field exceedance.
Implementation Method 1
both the drive-roller main body and the opposing-roller main body are made of an elastic material... when the card-like medium is nipped, a drive-roller deformation amount of the drive-roller main body being elastically deformed in a direction away from the opposing-roller main body is equal to an opposing-roller deformation amount of the opposing-roller main body being deformed in a direction away from the drive-roller main body
Data Source
AI summary
An image reading device may include a conveyance path; a conveyance mechanism; and a first image sensor and a second image sensor that are disposed on both sides of the conveyance path. The conveyance mechanism may include a driving source; a pair of first conveyance rollers located upstream of a first and second image read position; and a pair of second conveyance rollers located downstream of the first and second image read position. The pair of first conveyance rollers may include a first drive roller; and a first opposing roller. The pair of second conveyance rollers may include a second drive roller and a second opposing roller.