Conductive Roller Surface Roughness for Even Charging
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Solution Overview
Problem
The excessive increase in insulating particles in conductive rollers leads to elevated electrical resistance, reducing discharge and making it difficult to achieve even charging of photoreceptors, thereby increasing image unevenness in electrophotographic processes.
Innovation Solution
A conductive roller with a surface layer having a ten-point height of irregularities Rz between 5.5 and 8.5 micrometers, which balances surface roughness and resistance, ensuring even discharge and reduced image unevenness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the amount of insulating particles is increased to roughen the surface layer, then the roughness of the surface layer is greater than that of the elastic layer, but the electrical resistance of the charging roller increases excessively
Solution Approach 1:
The patent changes the physical parameters of the base surface (Rz between 6.0-8.0 μm) to create a rougher foundation that compensates for the smoothing effect of insulating particles. This allows the surface layer to achieve adequate roughness for discharge while maintaining lower electrical resistance, as the base roughness provides the necessary discharge preference without requiring excessive insulating particle content
Solution Approach 2:
The patent creates a composite structure combining a rough base (with specific Rz parameters) and a surface layer containing insulating particles and conductive agents. This composite approach allows the base to provide structural roughness while the surface layer provides controlled electrical properties, resolving the contradiction between surface roughness and electrical resistance
2Reliability
If the electrical resistance of the charging roller is increased, then discharge is reduced, but it becomes difficult to obtain the electric potential required for the surface of the photoreceptor
Solution Approach 1:
By optimizing the base roughness parameter (Rz between 6.0-8.0 μm), the patent enhances discharge efficiency at lower electrical resistance values. The increased surface irregularities create more discharge points and improve charge transfer efficiency, allowing the system to achieve required electric potential with moderate resistance levels rather than requiring high resistance that would reduce discharge
3Manufacturing precision
If the surface roughness is increased to reduce image unevenness, then discharge preference is improved, but electrical resistance increases and discharge is reduced
Solution Approach 1:
The patent segments the charging roller into two functional parts: a base providing structural roughness (Rz 6.0-8.0 μm) for discharge preference, and a surface layer containing insulating particles and conductive agents for electrical property control. This segmentation allows each layer to optimize its function without compromising the other, achieving image uniformity while maintaining discharge efficiency
Solution Approach 2:
The patent changes the approach to roughness generation by specifying base surface parameters (Rz 6.0-8.0 μm) rather than relying solely on insulating particle content. This parameter change enables roughness optimization independent of electrical resistance, as the base roughness provides the physical irregularities needed for uniform discharge without requiring high concentrations of insulating particles
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 image unevenness by maintaining optimal electrical resistance and discharge, allowing for even charging of photoreceptors and improved image quality.
Implementation Method 1
by making a portion that discharges preferentially, image unevenness is reduced
Data Source
AI summary
A conductive roller includes a base including an outer surface along and about an axial line thereof, and a surface layer arranged on the outer surface of the base. The surface layer includes particles. The ten-point height of irregularities Rz of the outer surface of the base is greater than or equal to 6.0 micrometers and less than or equal to 8.0 micrometers. A ten-point height of irregularities Rz of an outer surface of the surface layer is greater than or equal to 5.5 micrometers and less than or equal to 8.5 micrometers. The base included in the conductive roller preferably includes a core member and a conductive elastic layer arranged between the core member and the surface layer. The surface layer preferably includes a conductive portion including a resin material and a conductive agent.