Polyurethane Lubricant Levelling Blade for Uniform Image Bearer Coating

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Solution Overview

Problem

Existing lubricant levelling blades in image forming apparatuses face challenges in maintaining consistent lubricant application and durability, especially in high-speed and low-temperature environments, leading to uneven lubricant distribution and increased friction, which can cause blade rolling and abnormal image formation.

Innovation Solution

A lubricant levelling blade with a polyurethane elastomer contact surface and a leading end ridge portion angle of 90 to 140 degrees, stabilized by a Martens hardness of 1.5 to 30.0 N/mm², prevents abrasion and ensures uniform lubricant distribution, enhancing durability and performance in high-speed, high-quality image formation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the lubricant is fed upstream the cleaning blade contact site, then the cleaning blade can level the lubricant, but the lubricant distribution becomes uneven due to residual toner interference

Engineering Contradiction:
Improvelubricant levelling functionVSAvoidlubricant distribution uniformity
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The patent feeds the lubricant downstream of the cleaning blade contact site, after the cleaning blade has already removed residual toner. This preliminary cleaning action ensures the lubricant applies to a clean surface, preventing toner-lubricant mixing and achieving uniform distribution without requiring the lubricant to level through toner interference

Inventive Principle:
Principle #10Preliminary action

2Manufacturing precision

If a lubricant levelling member is added to level the lubricant, then lubricant distribution improves, but the device complexity increases

Engineering Contradiction:
Improvelubricant distribution uniformityVSAvoidstructure complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent makes the cleaning blade perform dual functions: both cleaning the image bearer surface and levelling the lubricant. By positioning the lubricant feeding device downstream of the cleaning blade contact site, the cleaning blade's surface contact action naturally levels the lubricant without requiring an additional dedicated levelling member, thus avoiding increased device complexity

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Reliability

If the cleaning blade friction coefficient is reduced with lubricant, then blade rolling is prevented, but lubricant adhesion to surrounding members increases

Engineering Contradiction:
Improveblade rolling preventionVSAvoidlubricant adhesion
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent extracts the lubricant application location from the upstream area (where residual toner exists) and positions it downstream after the cleaning blade contact site. This separation ensures lubricant is applied only to clean areas, preventing lubricant adhesion to surrounding members while still achieving sufficient lubrication to prevent blade rolling

Inventive Principle:
Principle #2Taking out (Extraction)

4Reliability

If the lubricant amount is increased to ensure sufficient coverage, then friction reduction improves, but lubricant adhesion to charging member and developer bearer increases causing abnormal images

Engineering Contradiction:
Improvefriction coefficient reductionVSAvoidabnormal image formation
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent uses the cleaning blade as an intermediary mechanism that controls lubricant distribution. The cleaning blade's contact with the image bearer surface acts as a mediator that spreads and levels the lubricant uniformly, ensuring sufficient coverage for friction reduction while preventing excessive lubricant accumulation that would cause adhesion to charging members and abnormal images

Inventive Principle:
Principle #24Intermediary (Mediator)

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 lubricant levelling blade effectively stabilizes lubricant application, preventing uneven distribution and blade abrasion, ensuring high-quality image formation and extended durability in low-temperature conditions.

Implementation Method 1

A Martens hardness HM of a polyurethane elastomer forming a contact surface of an elastic member with an image bearer is high; i.e., 1.5 to 30.0 N/mm²

Methodology Applied
Scientific EffectMartens hardness:

Implementation Method 2

prevents abrasion and ensures uniform lubricant distribution, enhancing durability

Methodology Applied
Scientific EffectAbrasion resistance: Abrasion

Implementation Method 3

configured to feed a lubricant such as a fatty acid metal salt to an image bearer surface for reducing the friction coefficient between the cleaning blade and the image bearer surface

Methodology Applied
Scientific EffectFriction reduction: Friction

Data Source

PatentEP4314954B1Lubricant levelling blade, process cartridge, image forming apparatus, and image forming method
Publication Date: 2026.04.08 RICOH CO LTD
  • EP4314954B1 patent drawingFigure 1~3
  • EP4314954B1 patent drawingFigure 4~5

AI summary

Provided is a lubricant levelling blade (104) including an elastic member (1042) configured to contact a surface of an image bearer (3) to apply a lubricant to the surface of the image bearer. A contact surface (104c) of the elastic member with the image bearer is a polyurethane elastomer. A Martens hardness HM of the contact surface of the elastic member with the image bearer is 1.5 N/mm2 or higher but 30.0 N/mm2 or lower.