Dual-Side Scanner Roller Speed Control for Magnification Consistency
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Solution Overview
Problem
Existing image scanning devices face challenges in achieving high-speed scanning with high picture quality and appropriate magnification during dual-side scanning due to variations in document transportation speed and machinery differences, leading to degradation in image resolution and magnification consistency.
Innovation Solution
The solution involves configuring the scanning device with a controller that adjusts the transportation speed of rollers to match the scanning magnification in both directions, using a CCD and CIS scanner combination, and applying electronic decimation to ensure consistent magnification across different document lengths and thicknesses, while correcting for machinery differences using pre-calculated correction coefficients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the transportation speed of rollers is increased to enable high-speed scanning, then scanning speed is improved, but image resolution and magnification consistency deteriorate due to variations in document transportation speed
Solution Approach 1:
The patent applies dynamics by making the roller rotation speeds variable rather than fixed. The control unit dynamically adjusts the rotation speeds of the first and second rollers based on real-time detection of document transportation speed, allowing the system to maintain optimal imaging conditions at high scanning speeds while compensating for speed variations to preserve image resolution.
Solution Approach 2:
The patent implements feedback by using a sensor to detect the actual transportation speed of the document and feeding this information back to the control unit. The control unit then uses this feedback to calculate appropriate rotation speeds for the rollers, creating a closed-loop control system that maintains consistent image quality despite variations in document speed.
2Productivity
If the transportation speed of rollers is increased to improve productivity, then scanning throughput is improved, but magnification consistency deteriorates due to machinery differences and document variations
Solution Approach 1:
The system dynamically adjusts roller speeds based on actual document conditions. By making the rotation speeds variable and adapting them to each document's characteristics and transportation speed, the system maintains magnification consistency even at high throughput levels, resolving the contradiction between productivity and precision.
Solution Approach 2:
The patent changes the operational parameters (roller rotation speeds) based on detected document conditions. The control unit calculates and adjusts speed parameters in real-time to compensate for document length, thickness, and transportation speed variations, ensuring consistent magnification while maintaining high scanning throughput.
3Productivity
If dual-side scanning is implemented to improve productivity, then scanning throughput is improved, but image quality and magnification consistency deteriorate due to different scanning positions and speeds
Solution Approach 1:
The patent applies dynamics to dual-side scanning by independently controlling the rotation speeds of the first and second rollers for each scanning position. The control unit adjusts speeds dynamically based on the specific document section being scanned (front or back side) and its transportation speed, ensuring consistent image quality across both sides while maintaining high throughput.
Solution Approach 2:
The system applies local quality by tailoring the scanning parameters to the specific characteristics of each document side. The control unit detects the transportation speed at each scanning position and adjusts roller speeds accordingly, giving each scanning location its optimized parameters to maintain uniform image quality throughout the dual-side scanning process.
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 approach enables high-speed dual-side scanning with consistent image quality and magnification, minimizing the impact of document length and thickness variations and machinery differences, thereby improving overall scanning performance and reducing costs by optimizing image processing units.
Implementation Method 1
reading out the light reflected from the document at the scanning position
Implementation Method 2
a CIS line sensor reads the reverse side of the same
Data Source
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AI summary
An image scanning device includes a first scanner (141) scanning a top side of a transported document at a first scanning position (L1) to obtain a first scanned image, a second scanner (129) scanning the back side of the transported document at a second scanning position (L2) to obtain a second scanned image, a document feeder (63-70, 161) transporting a document at the second scanning position at a speed differing from the transportation speed at the first scanning position, and a controller (20) controlling the image scanning device. The controller sets, as a scanning form of a document, either one-side scanning of scanning one side of a document through one transportation, or dual-side scanning of scanning both sides of a document through one transportation. The controller also obtains a set magnification. The controller determines the transportation speed by the document feeder such that, when one-side scanning is set, the scanning magnification in a first direction corresponding to the document transportation direction at the first scanned image attains the set magnification, and when dual-side scanning is set, the scanning magnification in the first direction at the second scanned image attains the set magnification.