Transfer Unit Drive Roller Surface Roughness for Slippage Prevention
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Solution Overview
Problem
The existing image forming devices face a printing defect due to slippage between the transfer belt and the drive roller, caused by adhered developing agent, leading to potential image shrinkage and conveyability issues.
Innovation Solution
A transfer unit with a drive roller featuring a surface layer with a surface roughness greater than the volume mean particle diameter of the developing agent, enhancing frictional force and preventing slippage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the surface roughness of the drive roller is reduced to less than or equal to 2 μm, then damage on the back surface of the transfer belt is reduced, but slippage occurs between the drive roller and transfer belt when developing agent adheres, causing printing defects
Solution Approach 1:
The drive roller is designed with different surface roughness values for different regions or conditions. Specifically, the surface roughness is controlled to be greater than the volume mean particle diameter of the developing agent (e.g., 3-10 μm) to prevent slippage, while maintaining overall smooth operation. This local differentiation of surface properties resolves the contradiction between preventing belt damage and preventing slippage.
Solution Approach 2:
The invention changes the surface roughness parameter of the drive roller from the conventional ≤2 μm to a value greater than the volume mean particle diameter of the developing agent (e.g., 3-10 μm). This parameter change ensures that the developing agent particles cannot fill the surface irregularities, maintaining frictional force and preventing slippage, thereby resolving the reliability issue without compromising belt protection.
2Reliability
If the surface roughness of the drive roller is increased to prevent slippage, then printing defects due to slippage are prevented, but damage on the back surface of the transfer belt increases
Solution Approach 1:
The invention optimizes the surface roughness parameter to a specific range (greater than the volume mean particle diameter of the developing agent, e.g., 3-10 μm) that provides sufficient frictional force to prevent slippage while avoiding excessive roughness that would cause belt damage. This precise parameter control resolves the contradiction between preventing slippage and protecting the belt.
Solution Approach 2:
The drive roller may use composite material structures or surface treatments that provide controlled surface roughness characteristics. The surface layer is designed to have specific roughness properties that balance friction generation for slippage prevention with smoothness for belt protection, resolving the contradictory requirements through material composition design.
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
The solution effectively prevents printing defects such as image shrinkage by maintaining high frictional force between the transfer belt and the drive roller, ensuring stable conveyance and image quality.
Implementation Method 1
Surface roughness of an outer peripheral surface of the surface layer is greater than a volume mean particle diameter of the developing agent... enhancing frictional force and preventing slippage
Data Source
AI summary
A transfer unit that transfers a developing agent image formed with a developing agent, includes a belt; and a rotational body that stretches the belt. The rotational body includes a shaft body, and a surface layer provided on an outer side of the shaft body in radial directions. Surface roughness of an outer peripheral surface of the surface layer is greater than a volume mean particle diameter of the developing agent.