Sheet Conveyance Roller Coordination for Registration Stability
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Solution Overview
Problem
Existing sheet conveying devices often fail to stably register sheets due to resilient forces, leading to skewing and potential damage, especially when sheets with specific characteristics are conveyed.
Innovation Solution
A sheet conveying device with independently driven first and second convey rollers, where the second roller rotates in reverse to release the sheet from its nip, and the first roller adjusts its rotation to ensure proper alignment, using a controller to manage these movements based on sheet characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the second convey roller rotates in reverse direction to convey the sheet while the first convey roller is stopped, then the sheet is bent and an edge of the sheet is aligned with respect to the second convey roller, but the sheet may not be released from the nip of the second convey roller and may cause damage to the sheet
Solution Approach 1:
The system dynamically adjusts the rotation states of the first and second convey rollers based on sheet characteristics. The controller determines whether to rotate both rollers in reverse or only the second roller in reverse, adapting the conveyance mechanism to prevent sheet damage while maintaining alignment precision.
Solution Approach 2:
The invention changes the operational parameters (rotation direction and rotation amount) of the convey rollers based on sheet resilient force characteristics. By adjusting these parameters, the system resolves the contradiction between achieving precise alignment and ensuring reliable sheet release without damage.
2Manufacturing precision
If the sheet is bent between the first convey roller and the second convey roller for alignment, then edge alignment is achieved, but the sheet generates resilient force greater than nip force causing the second convey roller to slip
Solution Approach 1:
The system applies a counteracting force by rotating the first convey roller in reverse direction simultaneously with the second convey roller. This counter-rotation prevents excessive sheet bending and reduces the resilient force that causes slipping, while still achieving the necessary alignment through controlled nip pressure.
Solution Approach 2:
The dynamic control of both rollers' rotation states allows the system to adapt to different sheet resilient forces. By adjusting the rotation amounts and directions of both rollers, the system maintains optimal nip force balance to prevent slipping while achieving alignment.
3Reliability
If the second convey roller rotates in reverse direction alone, then sheet release is attempted, but alignment and deskewing of the sheet are impaired
Solution Approach 1:
The invention merges the functions of sheet release and alignment by coordinating the reverse rotation of both the first and second convey rollers. This combined action ensures that the sheet is properly released from the nip while simultaneously maintaining or improving alignment and deskewing accuracy.
Solution Approach 2:
The dynamic coordination of both rollers' reverse rotation allows the system to simultaneously achieve sheet release and maintain alignment. The controller adjusts the rotation amounts of both rollers to balance the competing requirements of release reliability and alignment precision.
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 approach stabilizes sheet registration and reduces skewing by aligning the sheet's leading edge with the second convey roller, effectively handling sheets with varying resilient forces.
Implementation Method 1
The sheet is bent between the first convey roller and the second convey roller, and an edge of the sheet is aligned with respect to the second convey roller
Data Source
AI summary
A first convey roller conveys a sheet in a sheet conveying direction such that a leading edge of the sheet passes through a nip of a second convey roller disposed downstream from the first convey roller. The second convey roller rotates in a reverse direction by a first rotation amount corresponding to a first linear distance to convey the sheet in a direction opposite to the sheet conveying direction, such that the leading edge of the sheet is released from the nip of the second convey roller. In response to the rotation of the second convey roller in the reverse direction, the first convey roller rotates by a second rotation amount corresponding to a second linear distance in the reverse direction to convey the sheet in the direction opposite to the sheet conveying direction, such that the leading edge of the sheet contacts the nip of the second convey roller when the first convey roller has rotated by the second rotation amount and the second convey roller has rotated by the first rotation amount.