Charging Member Surface Convexity Control for Image Streak Suppression
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Solution Overview
Problem
Existing contact-charging-type charging members in image forming apparatuses face challenges in suppressing the generation of streaks in images due to uneven surface convexities, which affect the charging uniformity and image quality.
Innovation Solution
A contact-charging-type charging member with a conductive core body, conductive elastic layer, and surface layer, where the height of convexities in a 0.7-mm-square area is measured and controlled to ensure an average proportion of 0.1% to 2% of the area is occupied by the charging member 1.7 μm lower than the reference height, using particles for forming concavities and convexities in each layer to achieve a desired shape and control the average proportion of areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If contact-charging-type charging members are used in image forming apparatuses, then charging function is provided, but streaks are generated in images due to uneven surface convexities
Solution Approach 1:
The patent applies local quality by creating specific surface structures with controlled convexities and concavities in different regions of the charging member surface. The surface is designed with convexities having specific height ranges (0.5-2.0 μm) and distribution patterns (average proportion of 0.1% to 2% of area) to achieve uniform charging while preventing streak formation. This local structural modification allows different areas of the surface to contribute differently to the overall charging performance.
Solution Approach 2:
The patent employs parameter changes by precisely controlling the physical dimensions and distribution characteristics of surface convexities. Key parameters include convexity height (0.5-2.0 μm), convexity area proportion (0.1% to 2% of total surface area), and three-dimensional surface profile. By adjusting these parameters, the charging uniformity is improved while streak generation is suppressed, transforming the surface geometry to optimize charging performance.
2Manufacturing precision
If particles for forming concavities and convexities are used in layers, then desired shape is achieved, but manufacturing complexity increases
Solution Approach 1:
The patent applies composite materials by incorporating particles for forming concavities and convexities into specific layers of the charging member structure. These particles are embedded within the layer matrix to create the desired surface topography. The composite structure combines the base layer material with particulate matter that self-organizes into convexities and concavities, achieving precise surface control through material composition rather than complex mechanical processing.
Solution Approach 2:
The patent employs self-service by utilizing particles that automatically form convexities and concavities during the layer formation or curing process. The particles self-organize into the desired surface structure without requiring additional post-processing steps. This self-organizing behavior of the particles simplifies manufacturing by eliminating the need for separate surface texturing operations, reducing overall manufacturing complexity while maintaining high precision.
Data Source
AI summary
A height of convexities in a 0.7-mm-square area of a surface of the charging member is measured at five or more different positions in an axial direction and calculated. A height of a position where the charging member occupies 0.01 area % from a highest portion is defined as a reference height. An average proportion of areas occupied by the charging member at a position 1.7 μm lower than the reference height is 2 area % or less relative to 100 area % of the 0.7-mm-square area.