Sheet Alignment Control via Transit Time Detection
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Solution Overview
Problem
In image forming apparatuses, sheet alignment accuracy deteriorates due to changes in roller surface properties caused by wear, leading to slippage and misalignment, as existing systems rely on preset values that do not account for changing conveyor mechanics.
Innovation Solution
The apparatus employs a control unit that calculates the transit time of sheets between sensors and adjusts the conveying distance and speed based on detected sheet type or thickness, ensuring accurate alignment by dynamically adjusting settings according to current conveyor conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If preset values corresponding to sheet type are used for sheet alignment, then alignment can be performed based on known characteristics, but slippage occurs on roller surface due to wear causing deterioration of alignment accuracy
Solution Approach 1:
The system dynamically changes the conveyance control parameters (conveyance distance, timing) based on detected roller wear state. The control unit adjusts these parameters according to the type of sheet and the detected roller characteristics, allowing the system to adapt to wear without manual reconfiguration while maintaining alignment accuracy.
Solution Approach 2:
The system implements feedback by detecting roller wear state through sensors (such as detecting slippage or conveyance time variations) and using this information to adjust the conveyance control parameters. This closed-loop approach allows the system to compensate for wear automatically, maintaining alignment precision without requiring manual intervention.
2Duration of action of stationary object
If roller surface properties change due to wear, then the conveying mechanism degrades over time, but using fixed preset values does not account for these changes leading to slippage
Solution Approach 1:
The system transitions from static preset values to dynamic parameter adjustment based on real-time detection of roller wear state. The control unit continuously adapts conveyance parameters according to the current roller condition and sheet type, ensuring reliable conveyance throughout the roller's service life without degradation in performance.
Solution Approach 2:
The system performs self-diagnosis and self-adjustment by detecting roller wear state and automatically modifying conveyance control parameters. This self-service capability allows the system to compensate for roller degradation without external intervention, maintaining reliable operation throughout the roller's lifespan.
3Manufacturing precision
If dynamic adjustment of conveying distance is implemented based on transit time, then alignment accuracy is maintained despite roller wear, but system complexity increases due to additional sensors and control calculations
Solution Approach 1:
The system replaces complex mechanical adjustment mechanisms with electronic detection and control calculations. Instead of physically adjusting roller properties or mechanical conveyance parameters, the system uses sensors to detect wear state and performs calculations to determine optimal conveyance parameters, simplifying the physical system while maintaining precision.
Data Source
AI summary
According to one embodiment, an image forming apparatus includes a conveying roller to convey sheets of different types along a conveyance path, a first sensor to detect a sheet being conveyed at a first position, a second sensor to detect the sheet being conveyed at a second position that is at a fixed distance downstream of the first position, a registration roller pair that is downstream of the second sensor, and a control unit. The control unit calculates a transit time for the sheet between the first position and the second position according detection results from the first and second sensors, and then sets a conveying distance for the sheet after the second position to be used for aligning the sheet against the registration roller pair based on the calculated transit time of the sheet.