Electrophotographic Conductive Layer for White Spot and Blur Control
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Solution Overview
Problem
Existing electrophotographic members face challenges in simultaneously suppressing white spot images caused by dirt substances and white blur images due to injection charging, especially in high-speed and long-life processes, leading to image deterioration.
Innovation Solution
The electrophotographic member features a conductive layer with a matrix of specific volume resistivity (1.00×10^8 to 1.00×10^12 Ω·cm) containing domains with a second rubber and electronic conductive agent, and an insulating region with a volume resistivity greater than 1.00×10^12 Ω·cm, controlled by impedance relationships (X/Y ≥ 7.5) to manage charge transportability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the charge transportability of the conductive layer is improved to eliminate electric charge on dirt substances, then white spot images caused by dirt are suppressed, but injection charging from the charging member to the photosensitive drum increases causing white blur images
Solution Approach 1:
The conductive layer is designed with non-uniform conductivity distribution through the domain matrix structure, where domains with different conductivity characteristics are distributed throughout the matrix. This allows different regions of the conductive layer to exhibit different charge transport properties, enabling suppression of both white spot images (through adequate charge transport to neutralize dirt charges) and white blur images (through controlled charge injection at the photosensitive drum contact region).
Solution Approach 2:
The conductive layer is constructed as a composite material consisting of a rubber matrix combined with conductive particles or conductive polymer domains. This composite structure provides tailored electrical properties that balance charge transport capability (to prevent white spot images from dirt) and charge injection control (to prevent white blur images on the photosensitive drum), resolving the technical contradiction between these two harmful effects.
2Productivity
If the charging member rotates at high speed to increase productivity, then image formation speed increases, but minute slip occurs at the contact region causing injection charging and white blur images
Solution Approach 1:
The electrical parameters of the conductive layer are optimized to compensate for the mechanical slip that occurs at high rotation speeds. By adjusting the conductivity distribution and charge transport properties of the conductive layer, the system maintains stable charge transfer to the photosensitive drum even when mechanical contact stability deteriorates due to high-speed rotation, thereby preventing white blur images while preserving high productivity.
3Duration of action of stationary object
If the service life of the charging member is extended to handle more dirt substances, then longer operation time is achieved, but accumulated dirt causes abnormal discharging and white spot images
Solution Approach 1:
The conductive layer is designed with self-cleaning functionality through its charge transport properties. The ability to transport charges within the layer allows accumulated dirt substances to have their electric charges neutralized over time, preventing the buildup of excessive charges that would cause abnormal discharging and white spot images. This enables the charging member to maintain image quality over extended service periods without requiring frequent cleaning or replacement.
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
This configuration effectively suppresses both white spot and white blur images by controlling charge transport at low and high potential differences, ensuring high-quality electrophotographic image formation.
Implementation Method 1
The conductive members play a role of transporting the charges from a conductive support member to a surface of the conductive member
Implementation Method 2
A charging member is a member that generates an electric discharge between itself and the photosensitive drum to charge the surface of the photosensitive drum
Implementation Method 3
provides charges to a contacted object by discharging or triboelectric charging
Data Source
AI summary
An electrophotographic member including a support member having a conductive outer surface; and a conductive layer disposed on an outer surface of the support member; wherein the conductive layer includes a matrix including a first rubber, and at least one domain dispersed in the matrix, volume resistivity of the matrix is 1.00×108 to 1.00×1012 Ω·cm, the at least one domain includes a domain A including a second rubber and an electronic conductive agent; the conductive layer further includes an insulating region including a third rubber; in a case where impedance of the electrophotographic member is measured under specific conditions, impedance X at a specific frequency is 1.00×106 to 1.00×108Ω; and a relationship between impedance Y under specific frequency and the impedance X satisfies X/Y≥7.5.