Electroconductive Rubber Layer for Uniform Electrophotographic Charging
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electroconductive members for electrophotography suffer from fogging issues when a high charging bias is applied, due to electric field concentration between irregularly shaped polymer particle phases, leading to inhomogeneous discharge and surface potential.
Innovation Solution
An electroconductive member with a matrix of crosslinked first rubber and domains of crosslinked second rubber and electroconductive particles, where 80% of domains satisfy specific impedance and shape criteria, preventing excessive current discharge and electric field concentration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a high charging bias is applied to enhance image contrast, then image quality improves, but fogging occurs due to electric field concentration between irregular polymer particle phases
Solution Approach 1:
The electroconductive layer is segmented into a matrix phase and dispersed particle phases, where the matrix provides uniform charge distribution and the particles provide conductivity. This segmentation prevents electric field concentration by distributing the electroconductive function across multiple phases rather than relying on irregular particle-particle contacts.
Solution Approach 2:
Different phases within the electroconductive layer have different local properties: the matrix phase has insulating characteristics to prevent charge leakage, while the dispersed particle phase has conductive characteristics to enable charge transfer. This local differentiation allows the layer to simultaneously achieve uniform discharge and sufficient conductivity.
2Power
If voltage is increased to enhance charging bias, then contrast improves, but toner transfers to white solid portions causing fogging
Solution Approach 1:
The electroconductive layer is designed to create an equipotential surface during charging operation, ensuring uniform potential distribution across the entire surface. This prevents localized high electric fields that would cause excessive charge transfer to non-image areas, thereby preventing fogging even at high voltages.
Solution Approach 2:
The electroconductive layer acts as an intermediary between the electroconductive support and the photosensitive member, mediating the charge transfer process. It controls the discharge characteristics to ensure uniform charging while preventing excessive charge transfer that would cause toner to transfer to white solid portions.
3Reliability
If polymer particle phases are used for electroconductivity, then conductivity is achieved, but irregular shapes cause electric field concentration and inhomogeneous discharge
Solution Approach 1:
The invention changes the morphological parameters of the electroconductive structure from irregular particles to a controlled matrix-dispersed particle system. This parameter change ensures that the electroconductive function is distributed uniformly throughout the layer, preventing electric field concentration while maintaining reliable conductivity.
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 prevents fogging on electrophotographic images by ensuring uniform discharge and potential distribution, even at high charging biases, enhancing image quality.
Implementation Method 1
an electroconductive member is constituted of an electroconductive layer covered with an outer peripheral surface of an electroconductive support. When the electroconductive member is used as a charging member or a transfer member, for example, the electroconductive member serves to charge a surface of a member to be charged by transferring charges from the electroconductive support to the electroconductive member surface
Implementation Method 2
an impedance is 1.0×103 to 1.0×108Ω when a platinum electrode is provided directly on an outer surface of the electroconductive member, and an alternating voltage is applied between an outer surface of the electroconductive support and the platinum electrode
Data Source
AI summary
A process for producing an electrophotographic electroconductive member having an electroconductive support and an electroconductive layer in the order mentioned. The electroconductive layer has a matrix including a crosslinked product of a first rubber, and a domain including a crosslinked product of a second rubber and an electroconductive particle, the process including the steps of: providing a rubber mixture for forming the domain, including carbon black and the second rubber by kneading the carbon black and the second rubber; providing a rubber mixture for forming the matrix, including the first rubber; kneading the rubber mixture for forming the domain and the rubber mixture for forming the matrix to prepare a rubber composition having a matrix-domain structure; forming a layer of the rubber composition on a surface of the electroconductive support; and curing the layer of the rubber composition on the surface of the electroconductive support to form the electroconductive layer.