Secondary Transfer Roller Position Adjustment for Image Quality
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Solution Overview
Problem
Existing image forming apparatuses face challenges in improving transferability for various types of recording materials with different stiffness, leading to issues like horizontal stripes and transfer defects due to conveyance path bending and velocity differences.
Innovation Solution
An image forming apparatus with a position changing mechanism for the secondary transfer inner roller, controlled by a controller to adjust the offset amount based on the recording material's thickness, optimizing the transfer portion's position to enhance transferability across different material types.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the secondary transfer outer roller is disposed upstream of the secondary transfer inner roller to improve separability, then separability is improved, but conveyance resistance increases and transfer defects occur for thick recording materials
Solution Approach 1:
The invention makes the position of the secondary transfer outer roller dynamic rather than fixed. A position changing mechanism adjusts the roller's position based on recording material thickness: for thick materials, the roller moves to a first position that reduces conveyance path bending; for thin materials, it moves to a second position that enhances separability. This dynamic adjustment resolves the contradiction between separability and conveyance resistance.
Solution Approach 2:
The invention changes the positional parameter of the secondary transfer outer roller according to recording material thickness. By varying the offset distance between the outer and inner rollers based on material properties, the system optimizes both separability and conveyance resistance for different material types, preventing transfer defects while maintaining reliable separation.
2Reliability
If the conveyance path is bent to improve separability, then separability is improved, but velocity difference occurs causing horizontal stripes and transfer defects
Solution Approach 1:
The position changing mechanism dynamically adjusts the secondary transfer outer roller's position to control the conveyance path's degree of bending. For thick recording materials, the roller is positioned to minimize path bending, maintaining uniform conveyance velocity and preventing horizontal stripes. For thin materials, the roller position creates appropriate bending for separability without causing velocity differences that lead to transfer defects.
3Device complexity
If the secondary transfer outer roller position is fixed, then device complexity is low, but transferability cannot be optimized for different recording material types
Solution Approach 1:
The invention introduces a position changing mechanism that enables the secondary transfer outer roller to switch between at least two positions based on recording material thickness. This dynamic capability allows the system to optimize transferability for different material types (thick vs. thin) while maintaining a relatively simple overall structure, resolving the contradiction between device complexity and adaptability.
Data Source
AI summary
A rotation center of a secondary transfer inner roller located at a first position is located downstream of a rotation center of a secondary transfer outer roller in a movement direction of an intermediate transfer belt tensioned by the secondary transfer inner roller and an idler roller. The rotation center of the secondary transfer inner roller located at a second position coincides in position with the rotation center of the secondary transfer outer roller, or is located upstream of the rotation center of the secondary transfer outer roller in the movement direction of the intermediate transfer belt tensioned by the secondary transfer inner roller and the idler roller.