Developer Supply Roller Elastic Layer Stress Reduction
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Solution Overview
Problem
Conventional electrographic image forming apparatuses with two supply rollers experience high external force on toner, leading to difficulties in maintaining desired image quality due to large stress on the toner during rotation.
Innovation Solution
The development apparatus incorporates a configuration with a first and second developer supply member, each with an elastic layer on its outer peripheral surface, arranged to come into press-contact with a developer carrier, where the hardness and layer thickness of these supply members are optimized to satisfy specific formulas ensuring balanced press-contact forces, reducing stress on the toner and maintaining image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If two supply rollers are rotated in press-contact with a development roller, then developer supply is achieved, but large external force (stress) is applied to the toner, deteriorating image quality
Solution Approach 1:
The patent changes the physical parameters of the supply rollers by forming elastic layers on their outer peripheral surfaces with specific hardness values (Hs1, Hs2) and thicknesses (t1, t2). These parameter changes allow the rollers to deform elastically during press-contact, reducing the stress transmitted to the toner while maintaining effective developer supply to the development roller.
Solution Approach 2:
The supply rollers are constructed as composite structures with an inner core and an outer elastic layer. This composite material approach allows the rigid core to maintain structural integrity and rotational stability, while the elastic layer provides compliant contact with the development roller, reducing harmful stress on the toner particles during developer supply.
2Object-affected harmful factors
If elastic layers are formed on supply rollers with optimized hardness and thickness, then stress on toner is reduced, but device complexity increases
Solution Approach 1:
The patent specifies quantitative parameters for the elastic layers (hardness Hs1, Hs2 and thickness t1, t2) that satisfy a particular mathematical relationship. By defining specific parameter ranges and relationships, the patent simplifies the design process and makes the complex elastic layer structure manageable through clear specification criteria.
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 reduces stress on the toner, allowing for the maintenance of predetermined image quality by optimizing the press-contact forces between the supply rollers and the developer carrier, thereby enhancing the image forming process.
Implementation Method 1
an elastic layer is formed on an outer peripheral surface of each of the first developer supply member and the second developer supply member
Data Source
AI summary
A development apparatus includes a developer carrier to develop an electrostatic latent image using a developer, a first and second developer supply members each to supply the developer to the developer carrier. Hs1, Δ1, t1, Hs2, Δ2, and t2 satisfy a following formula below,10≦Hs1×(Δ1/t1)+Hs2×(Δ2/t2)≦50Herein, Hs1 is a hardness of the outer peripheral surface of the first developer supply member, t1 is a layer thickness of an elastic layer of the first developer supply member, Δ1 is an NIP amount that is determined when the first developer supply member is in press-contact with the developer carrier, Hs2 is a hardness of the outer peripheral surface of the second developer supply member, t2 is a layer thickness of an elastic layer of the second developer supply member, and Δ2 is an NIP amount that is determined when the second developer supply member is in press-contact with the developer carrier.