Driven Roller Elastic Portion for Sheet Conveyance
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Solution Overview
Problem
The existing sheet conveying apparatus in image forming devices experiences slippage between the driven roller and the sheet due to a glazed surface, leading to reduced conveying force and lopsided wear on the rollers when not in contact with a sheet.
Innovation Solution
The driven roller's peripheral surface is covered with an elastic material, such as rubber, to increase friction and maintain conveying force, while the roller design includes a shaft portion with extending portions and a helical torsion spring to prevent lopsided wear by ensuring even contact and pressure distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the driven roller's peripheral surface is covered with rubber to increase friction force, then conveying force is maintained, but lopsided wear occurs on the peripheral surface of the drive roller or driven roller
Solution Approach 1:
The patent changes the physical parameters of the roller system by introducing an elastic portion made of resin that is fitted over the shaft portion. This elastic portion deforms elastically to provide uniform contact pressure between the drive roller and driven roller, preventing lopsided wear while maintaining adequate conveying force through controlled friction.
Solution Approach 2:
The driven roller is constructed as a composite structure with a shaft portion made of resin and an elastic portion (also resin-based) fitted over it. This composite design combines the structural integrity of the shaft with the elastic deformation capabilities of the outer layer, enabling both force transmission and uniform wear distribution.
2Device complexity
If the driven roller and drive roller rotate with their rubber surfaces in contact without a sheet between them, then the structure is simple, but lopsided wear occurs due to non-parallel rotation axes
Solution Approach 1:
The elastic portion acts as a cushioning element that is pre-installed on the shaft portion. This cushioning layer compensates for the non-parallel alignment of rotation axes by deforming elastically during roller contact, preventing direct metal-to-metal or resin-to-resin contact that would cause lopsided wear, while allowing the simple structural arrangement to be maintained.
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 configuration ensures smooth sheet conveyance and reduces lopsided wear on the rollers by maintaining consistent frictional resistance and pressure distribution, preventing further wear on the peripheral surfaces.
Implementation Method 1
The elastic portion is made of resin and has a cylindrical shape. The elastic portion is fitted over the shaft portion and has an outer peripheral surface in contact with a peripheral surface of the driven roller.
Implementation Method 2
the peripheral surface of the driven roller contacts a surface of a sheet having a relatively large filled-in area, the surface of the sheet is glazed and thus the driven roller may slip on the glazed surface, which may reduce a conveying force required for moving a sheet toward one side in the width direction
Data Source
AI summary
A sheet conveying apparatus includes a bottom plate, a side restriction member extending in a sheet conveying direction, a drive roller rotatable about a first axis substantially orthogonal to the sheet conveying direction, and a driven roller facing the drive roller and rotatable about a second axis inclined relative to the first axis. The driven shaft includes a shaft portion and an elastic portion. The shaft portion integrally includes a first extending portion, a second extending portion, and an intermediate portion located therebetween. The elastic portion is fitted over the intermediate portion. The first extending portion includes a first protruding portion. The second extending portion includes a second protruding portion. A first distance from the second axis to an outer peripheral surface of the first protruding portion is greater than a second distance from the second axis to an outer peripheral surface of the second protruding portion.