Sheet Transport Error Detection Using Threshold Comparison
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Solution Overview
Problem
Existing sheet transporting mechanisms in image reading and printing apparatuses require complex mechanisms to determine and handle transporting errors, leading to potential damage to the apparatus and the sheet due to time lags in detecting paper jams and motor failures.
Innovation Solution
A sheet transporting apparatus that compares different threshold values with the distance traveled by the sheet transporting mechanism per unit time to accurately determine the level of transporting errors, thereby eliminating errors and preventing electrical and mechanical damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the driving motor is driven until the encoder count value reaches a predetermined value to detect paper jam, then the paper jam detection is performed, but there is a time lag that may damage the jammed document sheet
Solution Approach 1:
The patent applies preliminary action by continuously monitoring the relationship between encoder count values and document sheet position before a paper jam fully develops. The system proactively identifies abnormal conditions by comparing expected vs. actual sheet positions at multiple threshold levels, enabling early intervention before the motor continues driving and causes damage.
Solution Approach 2:
The patent implements feedback by continuously comparing the encoder count value with the actual document sheet position detected by sensors. The controller receives real-time feedback about sheet transport status and adjusts motor operation accordingly. Multiple threshold values provide graduated feedback levels that trigger different responses based on the severity of the deviation.
2Adaptability or versatility
If a mechanism switches driving between feeding roller and transporting roller based on motor rotational direction, then the second driving process can be performed, but the apparatus may be electrically and mechanically damaged
Solution Approach 1:
The patent extracts the error determination logic from the mechanical switching mechanism. Instead of relying on motor rotational direction to switch between feeding and transporting rollers, the system independently determines error types based on encoder and sensor data, then selectively activates only the necessary roller. This separates the diagnostic function from the actuation mechanism, preventing unnecessary motor operations that could cause damage.
Solution Approach 2:
The system performs self-diagnosis by continuously monitoring transport parameters and automatically determining error conditions without requiring external intervention or complex switching mechanisms. The controller uses feedback from encoders and sensors to self-identify the type of error and initiate appropriate corrective action, reducing mechanical complexity and potential failure points.
Data Source
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AI summary
A sheet transporting apparatus, whereby the level of a transporting error for a sheet, such as a document or a printing medium, can be appropriately determined and coped with, and an image reading apparatus and an image printing apparatus equipped with this sheet transporting apparatus, are provided. In the image reading apparatus, in order to transport a sheet of a document, the driving amount per unit time (Dx) of a transporting roller is compared with a plurality of different threshold values (Ta, Tb), and the results obtained by comparison are employed to determine whether a transporting error is a service error or an operator error.