Downstream Encoder Scale for Image Reading Disturbance
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Solution Overview
Problem
Existing image reading devices experience image quality degradation due to disturbances in medium movement caused by instantaneous state changes when the medium transitions from being transported by one roller to another, as the encoder scale is typically mounted on the upstream roller, leading to inaccurate measurement of movement distance.
Innovation Solution
The image reading device incorporates an encoder scale mounted on the rotation shaft of the downstream transporting roller, allowing for precise measurement of movement distance and detection of disturbances, while also optimizing space efficiency through a miniaturized design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the encoder scale is installed on the medium transporting roller positioned upstream of the reading section, then the movement amount of the medium can be measured, but the image quality deteriorates due to disturbance when the medium transitions from one roller to another
Solution Approach 1:
A second encoder scale is installed on the medium discharge roller positioned downstream of the reading section, serving as an intermediary measurement point. This allows the system to measure the actual movement distance of the medium after it passes through the reading section, enabling detection and correction of any movement disturbances that occur during roller transitions.
Solution Approach 2:
The system calculates the difference between the movement distance measured by the first encoder scale (on the transporting roller) and the second encoder scale (on the discharge roller). This feedback mechanism enables the system to detect movement disturbances and apply image correction to compensate for the discrepancies, thereby maintaining image quality.
2Device complexity
If the encoder scale is installed on the upstream roller, then the device structure is simpler, but the measurement accuracy deteriorates due to instantaneous state changes during medium transition
Solution Approach 1:
The measurement function is segmented into two independent encoder scales: the first encoder scale on the medium transporting roller for initial movement measurement, and the second encoder scale on the medium discharge roller for final movement verification. This segmentation allows each encoder to perform its specific measurement function independently, improving overall measurement accuracy during roller transitions.
Solution Approach 2:
The second encoder scale acts as an intermediary verification mechanism that measures the actual movement distance after the medium passes through the reading section. By comparing the measurements from both encoder scales, the system can identify and correct measurement errors caused by instantaneous state changes during medium transition.
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 effectively reduces image quality deterioration by accurately measuring movement distance and detecting disturbances, enhancing measurement accuracy and space utilization, thereby improving image correction and device compactness.
Implementation Method 1
a measuring section configured to measure the rotational position of an encoder scale by an encoder sensor
Data Source
AI summary
An image reading device includes a motor 3, a reading section 7 that reads an image on a medium 5, a first transporting roller 9 that transports the medium in a transport direction F by driving force of the motor and that is provided upstream of the reading section in the transport direction, a second transporting roller 11 that transports the medium in the transport direction by driving force of the motor and that is provided downstream of the reading section in the transport direction, and a measuring section 17, using an encoder sensor 15, configured to measure the rotational position of an encoder scale 13, wherein the encoder scale 13 is provided on a rotation shaft 19 of the second transporting roller 11.