Electrophotographic Member Protrusion Elastic Modulus

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Solution Overview

Problem

Electrophotographic members used in high-temperature and high-humidity environments experience a reduction in image density due to the expansion and contraction of insulating regions, leading to minute cracks and decreased electrical resistivity, which affects toner conveyance.

Innovation Solution

An electrophotographic member with an electro-conductive substrate, an elastic layer, and a coating layer, featuring a first protrusion on the elastic layer and a second protrusion on the outer surface, which suppresses expansion and contraction, maintaining the intensity of the micro closed electric field and preventing toner conveyance issues.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If an electrophotographic member is used in a high-temperature and high-humidity environment, then it can operate in severe conditions, but the insulating regions expand and contract causing minute cracks and reduced electrical resistivity

Engineering Contradiction:
Improveenvironmental adaptabilityVSAvoidelectrical resistivity stability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies this principle by introducing an elastic layer between the insulating region and the substrate. This elastic layer acts as a flexible buffer that can deform elastically in response to thermal expansion and contraction, preventing the formation of minute cracks in the insulating region while maintaining electrical resistivity stability during temperature and humidity changes

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The patent applies this principle by controlling the elastic modulus of the elastic layer within a specific range (0.1 MPa to 10 MPa). By optimizing this physical parameter, the elastic layer provides sufficient flexibility to accommodate thermal stress while maintaining structural integrity, thus preventing crack formation and electrical resistivity degradation in high-temperature and high-humidity environments

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If the elastic layer has high elasticity to accommodate expansion, then it can prevent cracks, but the coating layer becomes difficult to apply uniformly

Engineering Contradiction:
Improvecrack resistanceVSAvoidcoating uniformity
Core Design Contradiction:
Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The patent applies this principle by precisely controlling the elastic modulus of the elastic layer within the range of 0.1 MPa to 10 MPa. This optimized elasticity range provides sufficient flexibility to prevent cracks while maintaining a relatively flat surface that facilitates uniform coating application, thus resolving the contradiction between crack resistance and coating uniformity

Inventive Principle:
Principle #35Parameter changes

3Reliability

If water enters into the insulating region through cracks, then electrical resistivity decreases, but toner conveyance is affected

Engineering Contradiction:
Improveelectrical resistivityVSAvoidtoner conveyance
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent applies this principle by using the elastic layer as a protective flexible barrier that prevents water from penetrating into the insulating region through cracks. By maintaining the integrity of the insulating region and preventing water ingress, the elastic layer preserves both electrical resistivity and toner conveyance performance in high-humidity environments

Inventive Principle:
Principle #30Flexible shells and thin films

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 stabilizes toner conveyance and maintains image density by reducing the formation of cracks and water ingress into the insulating region, ensuring consistent performance even in severe environments.

Implementation Method 1

the elastic layer has, on a surface thereof on a side opposite to a side facing the substrate, a first protrusion... the elastic layer has an elastic modulus, as measured in an environment of a temperature of 30°C and a relative humidity of 80%, of 0.5 MPa or more to 3.0 MPa or less

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

the outer surface of the electrophotographic member has one or more of electrical insulating first region(s) and an electro-conductive second region... the coating layer has an elastic modulus, as measured in the environment, of 5.0 MPa or more to 100.0 MPa or less

Methodology Applied
Scientific EffectElectrical insulation: Electrical Resistance

Implementation Method 3

an electrophotographic member equipped with a dielectric part having a high electrical resistance on the surface of its conductive part and therefore capable of conveying a toner electrically adsorbed to the charged dielectric part

Methodology Applied
Scientific EffectElectrostatic adsorption: Electrostatics

Data Source

PatentEP3605241B1Electrophotographic member, electrophotographic process cartridge and electrophotographic image forming apparatus
Publication Date: 2021.03.10 CANON KK
  • EP3605241B1 patent drawingFigure 1A~1B
  • EP3605241B1 patent drawingFigure 2
  • EP3605241B1 patent drawingFigure 3

AI summary

To provide an electrophotographic member causing less change in toner conveyance even used in a high-temperature and high-humidity environment. The electrophotographic member has an electro-conductive substrate, an elastic layer on the substrate and a coating layer on the elastic layer. The elastic layer has a first protrusion on a surface thereof on a side opposite to a side facing the substrate. The electrophotographic member has, on an outer surface thereof, a second protrusion derived from the first protrusion. The outer surface of the electrophotographic member has one or more of electrical insulating first region(s) and an electro-conductive second region. The elastic layer has an elastic modulus of 0.5 MPa or more to 3.0 MPa or less and the coating layer has an elastic modulus of 5.0 MPa or more to 100.0 MPa or less as measured in an environment of a temperature of 30°C and a relative humidity of 80%.