Conductive Member with Stepped Resistance Layer for Gap Stability
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Solution Overview
Problem
Contact-type charging devices for image forming apparatuses face issues such as shape distortion of gap retaining members, leading to unstable conductivity gaps between the charge roller and photoconductive drum, causing charging noise and reduced charging ability due to residual toner and permanent distortion from alternating voltage applications.
Innovation Solution
An electrical conductive member with a long conductive supporter, an electric resistance adjusting layer, and gap retaining members with steps to maintain a constant gap, preventing distortion and ensuring accurate long-term conductivity by fixing the gap retaining members on the steps of the electric resistance adjusting layer, allowing for adjustments in thickness and material to maintain gap stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If gap retaining members are fitted onto end surfaces of the electrical resistance adjusting layer, then the gap between the charge roller and photoconductive drum is maintained, but the gap retaining members undergo shape distortion causing unstable gap and defective conductivity
Solution Approach 1:
The electrical resistance adjusting layer is divided into multiple sections along the axial direction, with each section having a different external diameter to form stepped portions. This segmentation prevents the gap retaining members from being pressed onto a continuous surface, thereby preventing shape distortion while maintaining gap stability.
Solution Approach 2:
The stepped portions of the electrical resistance adjusting layer act as intermediaries between the gap retaining members and the charge roller body. These stepped portions provide stable abutting surfaces that prevent direct pressing of the gap retaining members onto the end surfaces of the adjusting layer, thus preventing shape distortion and maintaining reliable conductivity.
2Productivity
If contact-type charging device is used, then charging ability is improved, but substance from charge roller exudes and adheres onto photoconductive drum causing traces of charge roller
Solution Approach 1:
The patent replaces the mechanical contact-based charging system with a non-contact electrostatic induction charging system. The charge roller is positioned close to the photoconductive drum surface without physical contact, using electrostatic fields to achieve charging while eliminating mechanical wear and substance exudation.
3Productivity
If alternating voltage is applied to charge roller, then charging efficiency is improved, but charge roller vibrates causing charging noise
Solution Approach 1:
The non-contact gap structure acts as an intermediary that decouples the charge roller from the photoconductive drum, allowing alternating voltage application for efficient charging while preventing direct vibration transmission that causes charging noise.
4Productivity
If charge roller contacts photoconductive drum, then charging is achieved, but permanent distortion occurs in abutting portion after long-term rest
Solution Approach 1:
The patent eliminates the mechanical contact system entirely by using non-contact electrostatic induction charging. The charge roller maintains a small gap from the photoconductive drum surface, achieving charging function through electrostatic fields while completely avoiding permanent distortion of the abutting portion.
Data Source
AI summary
An electrical conductive member is configured to prevent a shape distortion in gap retaining members caused by that the gap retaining members are fitted to an end surface of an electric resistance adjusting layer, and to be able to maintain a gap between the electric residence adjusting layer and an image carrier for a long-term in a constant state with a high accuracy.