Electrophotographic Blade with Dual-Material Polyurethane Edge and Base

Solution Overview

Problem

Electro-photographic device blades face challenges with ester polyurethane's hydrolysis and wear resistance, while ether polyurethane lacks sufficient wear resistance, necessitating a material solution that balances mechanical strength, minimal deformation, and temperature stability.

Innovation Solution

A blade design using ester polyurethane for the edge and nip, combined with ether polyurethane for the base, where the ether polyurethane is specifically polytetramethylene glycol or polyoxy propylene urethane, with controlled hardness and visco-elastic properties, and a manufacturing method involving a rotary drum with a forming groove for continuous forming.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If ester polyurethane is used for the blade, then wear resistance is improved, but pressure contact performance deteriorates over time due to hydrolysis

Engineering Contradiction:

Improvewear resistanceVSAvoidpressure contact performance stability

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The blade is divided into two distinct layers: an edge layer made of ester polyurethane for wear resistance, and a base layer made of ether polyurethane for hydrolysis resistance. This segmentation allows each layer to perform its specialized function, resolving the contradiction between wear resistance and long-term stability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention uses a composite structure combining ester polyurethane and ether polyurethane in a layered configuration. The ester polyurethane edge layer provides superior wear resistance, while the ether polyurethane base layer provides resistance to hydrolysis, creating a material system that exhibits both wear resistance and long-term stability.

Inventive Principle:

Principle #40Composite materials

2Reliability

If ether polyurethane is used for the blade, then resistance to hydrolysis is improved, but wear resistance deteriorates

Engineering Contradiction:

Improveresistance to hydrolysisVSAvoidwear resistance

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The blade is divided into two distinct layers: an edge layer made of ester polyurethane for wear resistance, and a base layer made of ether polyurethane for hydrolysis resistance. This segmentation allows each layer to perform its specialized function, resolving the contradiction between wear resistance and long-term stability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention uses a composite structure combining ester polyurethane and ether polyurethane in a layered configuration. The ester polyurethane edge layer provides superior wear resistance, while the ether polyurethane base layer provides resistance to hydrolysis, creating a material system that exhibits both wear resistance and long-term stability.

Inventive Principle:

Principle #40Composite materials

3Reliability

If strong pressure contact is applied to clean toner without fail, then cleaning performance is improved, but permanent deformation of the blade increases

Engineering Contradiction:

Improvecleaning performanceVSAvoidpermanent deformation

Core Design Contradiction:

ReliabilityVSShape

Solution Approach 1:

The edge layer is designed with specific local properties (ester polyurethane composition, controlled hardness, specific thickness) to optimize cleaning performance while minimizing deformation. This local quality enhancement at the contact surface allows effective toner cleaning without excessive permanent deformation.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS8275302B2Blade for electrophotographic device with elastic rubber member constituted by edge/nip and base portions of different materials

Publication Date: 2012.09.25 BANDO CHEM IND LTD

AI summary

A blade for an electro-photographic device includes an elastic rubber member constituted by an edge portion and a base portion which are in contact with each other and are constituted by different materials, wherein the edge portion includes an edge subject to frictional wear in use and is made of ester polyurethane, and the base portion is adapted to be bonded to a support and is made of ether polyurethane. The blade undergoes minimal permanent deformation and offers excellent mechanical strength, wear resistance and compliance to the use environment.