Polyurethane Cleaning Blade Composition for Chipping Resistance

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Solution Overview

Problem

Existing electrophotographic cleaning blades suffer from chipping resistance issues, particularly in low-temperature and low-humidity environments, leading to defective cleaning performance.

Innovation Solution

A cleaning blade with a polyurethane elastomer composition that includes specific ranges for elastic modulus, coefficient of variation, Martens hardness, and hard segment dispersion, along with a support member, to enhance chipping resistance and cleaning performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a cleaning blade is used in a low-temperature and low-humidity environment, then cleaning performance may be maintained, but chipping occurs reducing reliability

Engineering Contradiction:

Improvechipping resistanceVSAvoidenvironmental condition sensitivity

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent modifies the physical and chemical parameters of the polyurethane elastomer by controlling the hard segment content (10-30 mass%) and aggregate size (0.1-1.0 μm), which changes the material's mechanical properties to resist chipping in low-temperature and low-humidity environments while maintaining cleaning performance

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The cleaning blade uses a composite polyurethane elastomer structure combining hard segments (providing strength and chipping resistance) and soft segments (providing flexibility and cleaning contact), creating a material that performs reliably across varying environmental conditions

Inventive Principle:

Principle #40Composite materials

2Reliability

If the cleaning blade structure is optimized for chipping resistance, then reliability improves, but manufacturing complexity increases

Engineering Contradiction:

Improvechipping resistanceVSAvoidblade structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies local quality by creating hard segment aggregates of specific size (0.1-1.0 μm) distributed within the polyurethane elastomer, concentrating strength properties where needed to prevent chipping at the blade edge while maintaining overall blade flexibility and simplicity

Inventive Principle:

Principle #3Local quality

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 cleaning blade achieves excellent chipping resistance and stable cleaning performance, contributing to the formation of high-quality electrophotographic images even in challenging environmental conditions.

Implementation Method 1

the proportion of the area occupied by hard segment aggregates with a diameter of at least 0.1 μm and not more than 1.0 μm in a cross section is at least 5% and not more than 20%

Methodology Applied

Scientific EffectHard segment aggregation:

Data Source

PatentEP4071555B1Electrophotographic cleaning blade, process cartridge, and electrophotographic image forming device

Publication Date: 2026.02.18 CANON KK

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AI summary

The present invention is aimed at providing an electrophotographic cleaning blade that has excellent chipping resistance and can exhibit excellent cleaning performance. This cleaning blade is provided with an elastic member that comprises a polyurethane and a support member that supports the elastic member, and cleans the surface of a member to be cleaned, by bringing a part of the elastic member into contact with the surface of the member to be cleaned that is moving. The average value of the elastic modulus of the elastic member obtained when measured using SPM is at least 15 MPa and not more than 470 MPa, and the coefficient of variation thereof is not more than 6.0%.