Developing Roller Segmented Inner and Outer Layers
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Solution Overview
Problem
Conventional developing rollers with a porous inner layer and a seamless nonporous outer tube face issues with material selection, leading to inadequate flexibility, wear resistance, and image quality due to toner leakage and contamination.
Innovation Solution
A developing roller with a tubular inner layer formed from a semiconductive rubber composition containing ethylene propylene rubber, paraffin oil, and carbon black, combined with an outer layer of a seamless nonporous tube made from a polyurethane thermoplastic elastomer, carbon black, and crosslinked polymethyl methacrylate particles, optimizing flexibility and wear resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a porous inner layer is used to improve flexibility, then the roller body becomes more flexible, but wear resistance deteriorates due to increased material removal during sliding contact
Solution Approach 1:
The roller body is divided into two distinct layers: a porous inner layer providing flexibility and an outer layer providing wear resistance. This segmentation allows each layer to independently fulfill its specific function without compromising the other.
Solution Approach 2:
The roller body uses a composite structure combining a porous rubber-based inner layer with a nonporous polymer-based outer layer. This composite material approach integrates the advantages of both materials: the flexibility and porosity of rubber with the durability and wear resistance of polymer.
2Reliability
If seal members are used to prevent toner leakage, then toner containment is improved, but the roller body wears faster due to sliding contact with seal members
Solution Approach 1:
The outer layer is designed with sufficient thickness to serve as a cushioning layer that absorbs wear from sliding contact with seal members. This beforehand cushioning protects the porous inner layer from direct contact and excessive wear, maintaining both toner containment and structural integrity.
Solution Approach 2:
The outer layer acts as a flexible protective shell that covers and protects the porous inner layer from mechanical wear during operation. This thin film approach provides protection while maintaining the overall flexibility of the roller body.
3Reliability
If a nonporous outer tube is used to prevent toner leakage, then toner containment is improved, but flexibility deteriorates due to the rigid structure
Solution Approach 1:
The roller body is segmented into a porous inner layer for flexibility and a nonporous outer layer for containment. This segmentation allows the outer layer to provide toner containment while the inner layer maintains flexibility, resolving the contradiction between these two requirements.
Solution Approach 2:
The nonporous outer layer is nested over the porous inner layer, creating a layered structure where the outer layer provides containment and the inner layer provides flexibility. This nesting arrangement allows both functions to coexist without interfering with each other.
4Adaptability or versatility
If oil is added to soften rubber composition, then flexibility is improved, but contamination occurs due to oil bleeding on the surface
Solution Approach 1:
The harmful oil component is extracted from the outer layer composition and replaced with alternative softening approaches. The outer layer uses a polymer-based formulation without oil, eliminating the source of contamination while maintaining flexibility through the layered structure with the oily inner layer underneath.
Solution Approach 2:
The outer layer acts as an intermediary barrier between the oily inner layer and the external environment. This intermediate layer prevents oil from migrating to the surface and contaminating the photoreceptor, while still allowing the inner layer to provide flexibility.
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 improves the roller's flexibility, wear resistance, and image quality by balancing the proportions of carbon black and paraffin oil, reducing toner leakage and contamination, while maintaining suitable toner density and charge.
Implementation Method 1
crosslinking the rubber of the rubber composition of the tubular body
Implementation Method 2
carbon black having a DBP oil absorption amount of not less than 400 cm3/100 g
Implementation Method 3
blending the solid rubber, the crosslinking component and a foaming component for foaming the rubber
Data Source
AI summary
An inventive developing roller (1) includes a roller body (5) which includes an inner layer (2) having a porous structure and an outer layer (4) of a seamless nonporous tube. The porous structure of the inner layer (2) is formed from a semiconductive rubber composition containing ethylene propylene rubber, paraffin oil and carbon black having a DBP oil absorption amount of not less than 400 cm3/100 g. The nonporous tube for the outer layer (4) contains a polyurethane thermoplastic elastomer having a type-A durometer hardness of not higher than 93, carbon black and crosslinked PMMA particles having a median particle diameter of 5 μm to 20 μm.