Paper Thickness Detection Using Following Rollers
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Solution Overview
Problem
Existing paper thickness detection methods in image forming apparatuses face challenges in achieving high accuracy without deteriorating productivity, as vibrations from roller shafts affect measurement accuracy and can hinder the passage of thin papers, and increasing pressure between detection rollers either reduces accuracy or causes conveyance issues.
Innovation Solution
A paper thickness detecting device with a pair of rollers that can switch between driving and following rotation, using a displacement sensor to measure the displacement of the rollers as the paper passes through, allowing for accurate thickness detection without stopping paper conveyance and minimizing conveyance resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conveyance of the paper is stopped to detect the paper thickness with high accuracy, then the measurement precision is improved, but the productivity is deteriorated
Solution Approach 1:
The paper conveyance continues without stopping during thickness detection. The detection rollers follow the moving paper and perform measurement while the paper is in motion, eliminating the need to halt the conveyance system and maintaining continuous productivity.
Solution Approach 2:
The patent replaces the mechanical stopping mechanism with a sensor-based detection system. Instead of physically stopping the paper to measure thickness, a displacement sensor detects roller displacement electronically while the paper continues to move through the system.
2Measurement precision
If the pressure between the pair of detection rollers is increased to suppress the vibration, then the measurement precision is improved, but the performance of passing a paper is deteriorated
Solution Approach 1:
The patent converts the harmful vibration effect into a beneficial measurement signal. Instead of trying to suppress vibration through increased pressure, the system uses the displacement caused by vibration and paper thickness combined as the measurement parameter, detected by the displacement sensor.
Solution Approach 2:
The patent changes the detection parameter from direct thickness measurement under pressure to displacement measurement of the rollers. This parameter change allows detection without requiring high pressure, thus maintaining paper conveyance performance while achieving measurement precision.
3Measurement precision
If the conveyance resistance at the time of entry of a paper into a nip part of the pair of detection rollers is increased to allow the pair of detection rollers to follow, then the measurement precision is improved, but it becomes difficult to pass a thin paper having low rigidity
Solution Approach 1:
The patent makes the detection rollers dynamic rather than static. The rollers are allowed to follow the paper's motion and displacement in real-time, adjusting their position dynamically as the paper passes through. This eliminates the need for high conveyance resistance and allows thin papers to pass easily while still enabling accurate displacement-based thickness measurement.
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 enables high-accuracy paper thickness detection without impacting productivity, allowing for stable and precise measurement even with thin papers, by attenuating vibration noise and maintaining efficient paper conveyance.
Implementation Method 1
a displacement sensor that detects a displacement amount of the pair of paper thickness detecting rollers
Data Source
AI summary
A paper thickness detecting device that detects a paper thickness in accordance with a detection signal of a displacement sensor, includes: a pair of paper thickness detecting rollers including a first roller and a second roller that pinch a paper conveyed via a pair of conveyance rollers; and the displacement sensor that detects a displacement amount of the pair of paper thickness detecting rollers at the time when the paper passes through the pair of paper thickness detecting rollers, wherein the paper thickness is detected on the basis of the displacement amount of the pair of paper thickness detecting rollers that follows to rotate with respect to the paper conveyed via the pair of conveyance rollers.