Medium Conveyance Slip Detection and Threshold Adjustment
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Solution Overview
Problem
Medium conveying apparatuses face challenges in accurately determining conveyance abnormalities, such as paper jams, which can lead to medium damage due to the inability to detect slips and jams in a timely and precise manner.
Innovation Solution
The apparatus includes sensors and a processor to detect medium presence and calculate slip degrees between rollers, adjusting predetermined amounts based on past slip data to determine and prevent conveyance abnormalities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a fixed conveyance time threshold is used to detect paper jams, then the detection method is simple, but the accuracy is low and false detection occurs due to slip variations
Solution Approach 1:
The patent applies dynamics by making the conveyance time threshold variable rather than fixed. The threshold is dynamically adjusted based on the calculated slip degree from previous conveyance cycles. This allows the detection system to adapt to varying slip conditions while maintaining simple sensor hardware, thus improving detection accuracy without significantly increasing system complexity.
Solution Approach 2:
The patent implements feedback by using the calculated slip degree from one conveyance cycle to adjust the detection threshold for the next cycle. The processor continuously monitors conveyance time, calculates slip degree, and uses this information to update the threshold, creating a closed-loop system that improves detection accuracy over time while maintaining relatively simple system architecture.
2Reliability
If the conveyance time threshold is extended to account for slip, then false detection is reduced, but the response time to actual jams is delayed
Solution Approach 1:
The patent uses dynamics to create a variable threshold that adapts to actual slip conditions rather than using a fixed extended threshold. The threshold is calculated based on measured slip degree from previous cycles, allowing the system to extend the threshold only when necessary to account for actual slip, thereby maintaining high reliability while minimizing unnecessary time loss in detecting actual jams.
3Measurement precision
If slip degree calculation is implemented to adjust detection parameters, then detection accuracy improves, but the control system becomes more complex
Solution Approach 1:
The patent applies universality by making the processor perform multiple functions: it detects medium presence using sensors, calculates conveyance time, computes slip degree from the difference between commanded and actual conveyance, and adjusts detection thresholds. This multi-functionality allows the system to achieve high detection precision without adding dedicated hardware for each function, thereby limiting the increase in overall system complexity.
4Reliability
If predetermined conveyance amounts are adjusted based on past slip data, then medium damage is prevented, but the system requires more data processing
Solution Approach 1:
The patent applies partial action by adjusting the detection threshold based on the calculated slip degree rather than completely redesigning the conveyance control system. The processor uses the slip degree information to modify only the threshold parameter needed for abnormality detection, performing minimal necessary data processing to achieve improved reliability while avoiding excessive computational overhead.
Data Source
AI summary
A medium conveying apparatus includes a processor to determine that a conveyance abnormality of a medium has occurred when a first medium sensor does not detect the medium when a motor is driven by a first predetermined amount after starting feeding of the medium, or when a second medium sensor does not detect the medium when the motor is driven by a second predetermined amount after the first medium sensor detects the medium, and calculate a degree of a slip occurred between the medium and a feed roller from when a front end of the medium passes through a position of the first medium sensor until the front end of the medium passes through a position of the second medium sensor. The processor changes the first predetermined amount or the second predetermined amount based on the degree of the slip of a medium fed in the past.