Sheet Conveying Apparatus Curved Guide Angle Reduction
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Solution Overview
Problem
In image forming apparatuses, the need for a retreat conveying path to handle sheets of increasing size leads to a larger apparatus, and existing solutions that bend sheets at right angles increase guide resistance, causing buckling, especially in sheets with low stiffness, and can result in motor stepping-out, slipping, and skewing.
Innovation Solution
A sheet conveying apparatus with multiple curved portions that change the conveying direction of sheets, where the angle of change at the first curved portion is greater than at subsequent portions, reducing guide resistance and preventing buckling by maintaining sufficient shape holding force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a retreat conveying path is provided in an image forming apparatus to handle sheets of increasing size, then the apparatus can accommodate larger sheets, but the apparatus becomes larger
Solution Approach 1:
The patent implements a retreat conveying path that allows the sheet to be temporarily retreated and stored within the apparatus body. The sheet is conveyed to a retreat position, stored in a nested manner within the apparatus structure, and then retrieved when needed. This nesting approach enables the apparatus to handle larger sheets without proportionally increasing the overall apparatus size, as the retreat path is integrated into the existing apparatus volume.
2Area of stationary object
If the sheet is bent a plurality of times at a substantially right angle on the retreat conveying path to secure a retreat space, then the retreat space is secured in limited space, but the guide resistance applied to the leading end of the sheet increases
Solution Approach 1:
The patent replaces sharp right-angle bends with curved guiding surfaces that gradually change the sheet's conveying direction. The curved guides reduce the guide resistance by distributing the directional change over a longer path, preventing sudden force spikes that would occur at sharp corners. This curvature approach maintains effective retreat space utilization while minimizing resistance forces on the sheet leading end.
3Device complexity
If the sheet is bent at right angles on the retreat conveying path, then the retreat path is compact, but buckling of the sheet tends to occur, especially in sheets with low stiffness
Solution Approach 1:
The patent employs curved guiding surfaces and flexible support structures that adapt to the sheet's stiffness characteristics. These flexible guides conform to the sheet's natural bending behavior rather than forcing sharp angular changes, providing continuous support along the retreat path. This approach prevents buckling in low-stiffness sheets while maintaining a compact retreat path configuration suitable for various sheet types.
4Strength
If a sheet with high rigidity is conveyed to the reversing portion, then the sheet can be conveyed structurally, but the guide resistance transiently increases causing stepping-out of the conveying motor, slipping, and skewing
Solution Approach 1:
The patent implements dynamic adjusting mechanisms in the curved guides that adapt to the sheet's rigidity characteristics. The guiding surfaces can adjust their position or curvature radius in response to detected sheet properties, optimizing the guide resistance for each sheet type. This dynamic adaptation prevents transient resistance spikes that cause motor stepping-out and slipping, while maintaining reliable conveying of high-rigidity sheets through the reversing portion.
Data Source
AI summary
Disclosed is a sheet conveying apparatus, including: a conveying member conveying a sheet; and a first and second changing portions s configured to change a conveying direction of the sheet conveyed by the conveying member by curving the sheet, wherein the conveying direction of the sheet being conveyed by the conveying member is changed by the first changing portion so that the sheet is conveyed toward the second changing portion. The relationship θa>θb is satisfied where θa indicates an angle in which a conveying direction of the sheet is changed by the first changing portion and θb indicates an angle in which a conveying direction of the sheet is changed by the second changing portion.