Developing Member Insulating Domains for Stable Toner Carrying
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Solution Overview
Problem
Existing electrophotographic developing members exhibit varying toner carrying ability due to environmental conditions such as temperature and humidity, leading to inconsistent image quality.
Innovation Solution
An electrophotographic developing member with a substrate having an electroconductive outer surface and electrically insulating domains, where the insulating domains have a specific shape and distribution to maintain consistent toner carrying ability across different environmental conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a developing member with dielectric portions is used to carry toner, then toner carrying ability is improved, but toner carrying ability becomes sensitive to environmental conditions (temperature and humidity)
Solution Approach 1:
The developing member surface is divided into multiple regions with different electrical properties: dielectric portions for toner carrying and electroconductive portions for charge dissipation. This local differentiation allows the dielectric portions to maintain stable toner carrying ability while the electroconductive portions compensate for environmental variations, resolving the contradiction between toner carrying ability and environmental sensitivity.
Solution Approach 2:
The developing member combines dielectric material portions with electroconductive material portions to form a composite structure. The dielectric portions provide toner carrying capability while the electroconductive portions provide environmental compensation, creating a composite material system that simultaneously achieves high toner carrying ability and low environmental dependency.
2Reliability
If the developing member surface is made entirely electroconductive, then environmental stability is improved, but toner carrying ability is reduced
Solution Approach 1:
Instead of making the entire surface electroconductive, the invention creates local dielectric portions on the surface. These localized dielectric regions provide the necessary toner carrying ability while the surrounding electroconductive portions maintain environmental stability, resolving the contradiction between toner carrying ability and environmental stability.
Solution Approach 2:
The developing member surface is segmented into distinct dielectric portions and electroconductive portions. This segmentation allows each region to perform its specific function: dielectric portions for toner carrying and electroconductive portions for environmental compensation, achieving both high toner carrying ability and environmental stability simultaneously.
3Quantity of substance
If the developing member surface is made entirely dielectric, then toner carrying ability is improved, but environmental sensitivity increases
Solution Approach 1:
The electroconductive portions act as intermediaries between the dielectric portions and the environment. They mediate the interaction by providing a charge dissipation path that compensates for environmental variations, allowing the dielectric portions to maintain toner carrying ability while reducing overall environmental sensitivity.
Solution Approach 2:
The developing member uses a composite structure combining dielectric and electroconductive materials. The dielectric material provides toner carrying ability while the electroconductive material acts as an environmental buffer, creating a composite system that achieves high toner carrying ability with reduced environmental sensitivity.
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 developing member ensures stable and high-quality electrophotographic image formation by maintaining consistent toner carrying ability under varying environmental conditions, reducing the impact of temperature and humidity on image quality.
Implementation Method 1
a toner is electrically adsorbed by the charged dielectric portions to carry the toner
Implementation Method 2
when the surfaces of the domains constituting the outer surface of the developing member are electrically charged so as to have potential of V0 volt (V), a potential decay time constant defined as a period of time necessary for a potential of each of the surface of the domains to decay from V0 volt to V0× (1/e) (V) is 60.0 seconds or longer
Data Source
Figure 1A~1B
Figure 2
Figure 3A~3C
AI summary
The developing member includes a substrate having an electroconductive outer surface; an insulating layer on the outer surface of the substrate; and electrically insulating domains on an outer surface of insulating layer, and has an outer surface including a surface of the insulating resin layer and surfaces of the domains, wherein a potential decay time constant of each of the surfaces of the domains is ≥ 60.0 seconds, and a potential decay time constant of the surface of the electrically insulating layer is < 6.0 seconds, and assuming that the electrically insulating domains are orthographically projected onto the outer surface of the substrate, to obtain projection images of the respective domains, each of areas of the projection images is defined as S, and each of areas of convex envelopes of the projection images is defined as H, at least one of the domains satisfies 0.05 ≤ S/H ≤ 0.80.