Curved Sheet Conveyance Guides for Duplex Printing Without Buckling
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Solution Overview
Problem
Existing image forming apparatuses face issues with sheet buckling due to high resistance forces in conveyance paths with large curvatures, particularly at the junction of one-sided and two-sided conveyance paths, leading to buckling and design constraints.
Innovation Solution
A conveyance apparatus with a first and second conveyance roller pair, a moving member, and guides with curved portions to manage sheet curvature, reducing frictional resistance and reaction forces, ensuring smooth conveyance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the conveyance path curves in an S shape to enable two-sided conveyance, then the sheet can be conveyed back to the transfer unit for double-sided printing, but the curvature becomes large at the joint portion increasing resistance force and causing sheet buckling
Solution Approach 1:
The conveyance path is divided into separate one-sided and two-sided conveyance paths, with the two-sided path positioned below the one-sided path. This segmentation allows independent optimization of each path's geometry, enabling the two-sided path to have appropriate curvature without interfering with the one-sided path, thereby reducing resistance force and preventing sheet buckling while maintaining two-sided printing capability.
2Volume of moving object
If the curvature of the conveyance path is increased to enable compact design, then the apparatus size is reduced, but the resistance force acting on the sheet increases causing buckling
Solution Approach 1:
The two-sided conveyance path is positioned in a different spatial dimension (below the one-sided conveyance path) rather than increasing curvature in the same plane. This dimensional arrangement allows the path to return to the transfer unit with appropriate curvature radius, reducing the resistance force acting on the sheet while maintaining a compact overall apparatus layout.
3Speed
If the sheet conveyance force is increased to overcome large resistance force, then the sheet can be conveyed through large curvature, but the sheet buckles due to excessive force
Solution Approach 1:
The curvature radius of the conveyance path is optimized to balance conveyance speed and resistance force. By adjusting the curvature parameter to be neither too sharp nor too gentle, the system achieves smooth sheet flow with appropriate conveyance speed while minimizing resistance force that would cause buckling.
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
Prevents sheet buckling by managing frictional and reaction forces through guided curvature, enhancing conveyance efficiency and design flexibility.
Implementation Method 1
there may be a case where a force (resistance force) acts on the sheet in a direction in which the sheet conveyance is hindered by the sheet contacting other components
Implementation Method 2
the moving member being moved from the restricting position to the retracting position by being pushed by the sheet
Data Source
AI summary
A conveyance apparatus for conveying a sheet includes (i) a first conveyance roller pair, (ii) a second conveyance roller pair configured to convey the sheet to reach a position where the sheet contacts the first conveyance roller pair, (iii) a moving member movable between a restricting position where the sheet is regulated not to reach the first conveyance roller pair and a retracting position, to be moved to the retracting position from the restricting position by being pushed by the sheet, (iv) a first guide disposed between the moving member and the second conveyance roller pair, and (v) a first opposing guide opposing the first guide. One of the first guide and the first opposing guide includes a first curved portion which the sheet contacts, and the other one thereof includes a second curved portion which the sheet contacts.