Charge Roller Surface Friction and Cleaning for Image Quality
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Solution Overview
Problem
Existing charge assemblies in image formation apparatuses face issues with defective images due to toner, toner additives, and lubricant decompositions accumulating on the charge member, leading to decreased electrification performance and image quality.
Innovation Solution
A charge assembly with a conductive support body having a resistance adjusting layer and a surface layer with a static friction coefficient of 1.0 or more, made from resin materials containing fluorine or silicon, and a cleaning member made of porous melamine resin, which rotates in contact with the charge member to remove foreign particles, is used to prevent attachment and improve cleaning performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a charge member is used to electrically charge the photoreceptor surface, then electrification performance is improved, but foreign particles (toner, lubricant decomposition) accumulate on the charge member surface, leading to image defects
Solution Approach 1:
The patent applies parameter changes by controlling the surface hardness of the charge member within a specific range (40-80 degrees on the JIS A scale) and adjusting the crosslinking density of the elastic layer. These parameter modifications optimize the balance between maintaining electrification performance and preventing foreign particle accumulation, resolving the technical contradiction.
Solution Approach 2:
The charge member is constructed as a composite structure with a conductive substrate and an elastic layer containing specific resin components (polyurethane, polyacrylic acid, and their copolymers) with controlled crosslinking. This composite material design enables the surface to maintain appropriate friction characteristics that prevent particle accumulation while preserving charging functionality.
2Reliability
If the charge member surface friction is increased to prevent particle attachment, then cleaning performance is improved, but the surface may become too rough, affecting electrification uniformity
Solution Approach 1:
The patent precisely controls the surface hardness parameter within the range of 40-80 degrees (JIS A scale) and regulates the crosslinking density of the elastic layer. This parameter optimization ensures the surface has sufficient friction for particle removal while maintaining smoothness for uniform electrification, resolving the contradiction between cleaning performance and electrification precision.
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 reduces the generation of defective images by preventing toner and lubricant attachments on the charge member, maintaining high image quality over a long period and ensuring stable electrification.
Implementation Method 1
there are two known electrification techniques, that is, contact electrification in which the charge roller 12a is made in contact with the surface 11a of the photoreceptor 11
Implementation Method 2
a cleaning member 12b to remove foreign particles on the surface layer by contacting the surface layer of the charge roller 12a
Implementation Method 3
The surface layer 12n has a static friction coefficient of 1.0 or more
Data Source
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AI summary
The charge assembly according to the present invention includes a charge member (12a) having a conductive support body (12k) on which a resistance adjusting layer (12m) and a surface layer(12n) covering the resistance adjusting layer (12m) are formed, to rotate a surface of the image support body to electrically charge the image support body, the surface layer having a static friction coefficient of 1.0 or more; and a cleaning member (12b) rotating the surface layer (12n) of the charge member (12a) in contact therewith to remove foreign particles on the surface layer (12n).