Electroconductive Member Porous Surface Layer Suppresses Abnormal Discharge
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Solution Overview
Problem
Existing electroconductive members for electrophotography face challenges in stably charging electrically chargeable bodies, particularly due to increased charging voltage leading to abnormal discharge and electrostatic adhesion of dirt, which worsens in low-temperature and low-humidity environments.
Innovation Solution
An electroconductive member with a surface layer that is three-dimensionally continuous and porous, featuring a skeleton formed by particles connected through necks, with a limited number of through holes and non-electroconductive properties, which limits the diffusion of electron avalanches and reduces electrostatic adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If charging voltage is increased to improve charging ability, then charging efficiency is improved, but abnormal discharge occurs more frequently
Solution Approach 1:
The surface layer is designed as a porous structure with controlled pore distribution, where the number of through holes in a 150μm × 150μm region is 100 or less. This porous configuration allows controlled charge diffusion while preventing uncontrolled electron avalanche, enabling high charging voltage operation without abnormal discharge
Solution Approach 2:
The charging member comprises a composite structure with an electroconductive support and a non-electroconductive surface layer containing particles with specific properties. This composite design combines the electroconductive properties needed for charging with the insulating properties that prevent abnormal discharge, achieving both high charging ability and reliability
2Power
If charging voltage is increased to improve charging ability, then charging efficiency is improved, but electrostatic adhesion of dirt increases
Solution Approach 1:
The porous surface layer with limited through holes provides controlled charge diffusion that reduces electrostatic charge accumulation on the surface, thereby decreasing electrostatic adhesion of dirt while maintaining effective charging capability
Solution Approach 2:
The surface layer exhibits non-uniform pore distribution and particle arrangement, creating regions with different electrical properties. This local variation in structure allows optimal charge diffusion pathways that prevent both abnormal discharge and excessive electrostatic adhesion of contaminants
3Reliability
If surface layer is made porous to suppress abnormal discharge, then charging stability is improved, but manufacturing precision becomes more difficult to control
Solution Approach 1:
The invention specifies quantitative parameters for pore control (number of through holes ≤ 100 in 150μm × 150μm region) and particle properties (average diameter 0.1-20μm, neck diameter 0.01-2μm). These defined parameters provide clear manufacturing targets that balance charging stability with manufacturability
Solution Approach 2:
The surface layer uses particles that can be applied as a coating on the electroconductive support, allowing for relatively simple manufacturing processes. The particles form the porous structure through their arrangement and connection, providing a cost-effective approach to achieving controlled pore distribution
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 suppresses abnormal discharge and adhesion of dirt, ensuring stable charging and high-quality electrophotographic image formation over a long period.
Implementation Method 1
the surface layer includes a skeleton that is three-dimensionally continuous and a pore that communicates in a thickness direction... which limits the diffusion of electron avalanches
Implementation Method 2
the skeleton is non-electroconductive... which reduces electrostatic adhesion
Data Source
Figure 1~2B
Figure 3
Figure 4A~4D
AI summary
Provided is an electroconductive member for electrophotography capable of charging an electrically chargeable body stably over a long period of time. The electroconductive member includes an electroconductive support and a surface layer on the electroconductive support. The surface layer has a skeleton that is three-dimensionally continuous and a pore that communicates in a thickness direction, and when any region measuring 150 μm per side of a surface of the surface layer is photographed and equally divided into 60 parts in a vertical direction and 60 parts in a horizontal direction to form 3,600 squares, the number of squares including through holes is 100 or less. The skeleton is non-electroconductive and includes a plurality of particles connected to each other through a neck, and an average value D1 of circle-equivalent diameters of the particles is 0.1 μm or more and 20 μm or less.