Sheet Conveyance Position Correction and Speed Control
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Solution Overview
Problem
Existing sheet conveying devices in image forming apparatuses face challenges in accurately conveying sheets due to positional deviations, leading to decreased productivity and accuracy, as they cannot detect and correct angular and lateral displacements in real-time without stopping the conveyance process.
Innovation Solution
A sheet conveying device equipped with position detectors and a position adjuster that continuously detects the position of the sheet's side end and adjusts its position in both width and rotation directions within the plane of conveyance, while also adjusting the conveying speed based on detected changes, ensuring accurate and timely delivery to the target position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the sheet is abutted against the nip region of stopped sheet conveying rollers to correct angular displacement, then the positional accuracy of the sheet is improved, but the productivity decreases due to temporary stopping of conveyance
Solution Approach 1:
The system detects the position of the leading end of the sheet in advance during conveyance and calculates the required correction amount before the sheet reaches the target position. The sheet conveying rollers then rotate in the direction opposite to the positional deviation to correct the position while the sheet is still moving, eliminating the need to stop conveyance for correction.
Solution Approach 2:
The sheet conveying rollers dynamically adjust their rotation during conveyance to correct positional deviations. The rotation direction and speed are continuously adjusted based on real-time position detection, allowing the system to maintain both high accuracy and continuous conveyance without static stopping.
2Productivity
If the positional deviation is corrected while the sheet is being conveyed, then the productivity is maintained, but the timing accuracy of the leading end reaching the target position shifts
Solution Approach 1:
The system continuously detects the position of the leading end of the sheet during conveyance and uses this feedback to calculate the corrected position after correction. Based on this calculation, the conveying speed is dynamically adjusted to ensure the leading end reaches the target position at the correct timing, compensating for any timing shifts caused by positional correction.
3Device complexity
If the sheet conveying speed is adjusted based on one-time angular displacement detection, then the correction is performed once, but the sheet cannot be conveyed with high accuracy when further shifts occur after correction
Solution Approach 1:
The system continuously detects the position of the leading end of the sheet throughout the conveyance process, not just once. This continuous detection allows for multiple corrections if needed, ensuring high accuracy even when the sheet experiences further positional shifts during conveyance, while maintaining relatively simple control logic.
Data Source
AI summary
A sheet conveying device includable in an image forming apparatus that uses a method of conveying a conveyance target medium and a method of forming an image, includes a position detector, a position adjuster, and circuitry. The position detector is configured to detect a position of a conveyance target medium. Based on a detection of the position of the conveyance target medium by the position detector, the position adjuster moves in at least one of a width direction of the conveyance target medium and a rotation direction of the conveyance target medium within a plane of conveyance of the conveyance target medium and repeatedly adjusts the position of the conveyance target medium while conveying the conveyance target medium. The circuitry changes a conveying speed of the conveyance target medium, according to a change of the position of the conveyance target medium after adjusted by the position adjuster.