PFA-PFPE Fixing Roller Porous Reservoir for Toner Releasability

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Solution Overview

Problem

Conventional fixing rotating members in electrophotographic image forming apparatuses face challenges in maintaining high toner releasability over long periods, especially when handling thin paper, due to limited capacity for perfluoropolyether (PFPE) and potential adhesion of molten toner.

Innovation Solution

The development of a fixing rotating member with a surface layer containing a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA) and pores with openings on the outer surface, where at least part of the pores contains PFPE, allowing for a higher amount of PFPE to be held and supplied stably to the surface.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If fluorine oil is incorporated into the surface layer of the fixing rotating member, then toner releasability is improved, but the amount of fluorine oil that can be incorporated is limited

Engineering Contradiction:
Improvetoner releasabilityVSAvoidamount of fluorine oil
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent introduces a porous layer between the base layer and surface layer, where the porous structure with controlled pore size (0.1-10 μm) and porosity (10-80%) provides extensive internal surface area and volume for fluorine oil incorporation. The porous material acts as a reservoir that can hold significantly more fluorine oil than a non-porous structure of the same external dimensions, thereby resolving the contradiction between limited incorporation capacity and the need for high toner releasability.

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The patent implements a nested multi-layer structure where the porous layer is embedded within the fixing rotating member, surrounded by the base layer and surface layer. This nested configuration allows the fluorine oil-storing porous layer to be integrated within the overall structure without increasing external dimensions, enabling high fluorine oil content while maintaining the compact form factor required for fixing rotating members.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Quantity of substance

If a porous structure is introduced to increase fluorine oil capacity, then fluorine oil storage is improved, but structural complexity increases

Engineering Contradiction:
Improvefluorine oil storage capacityVSAvoidsurface layer structure
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The patent applies local quality by creating a porous structure specifically in the intermediate layer rather than throughout the entire fixing rotating member. The porous layer is strategically positioned between the base layer and surface layer, concentrating the complex porous structure only where fluorine oil storage is needed, while the base layer and surface layer maintain simpler structures optimized for their respective functions.

Inventive Principle:
Principle #3Local quality

3Reliability

If perfluoropolyether is supplied to the outer surface for toner releasability, then toner release is improved, but stability over long periods deteriorates

Engineering Contradiction:
Improvetoner releasabilityVSAvoidstability over time
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent implements preliminary action by pre-loading the porous layer with fluorine oil during the manufacturing process. The porous structure is formed and then saturated with fluorine oil before the surface layer is applied. This preliminary incorporation ensures that fluorine oil is already present in the porous reservoir, creating a sustained supply mechanism that maintains toner releasability over extended periods without requiring frequent replenishment.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent enables self-service through the autonomous diffusion mechanism where fluorine oil automatically migrates from the porous layer to the surface layer as needed. The concentration gradient between the fluorine oil-rich porous layer and the surface layer drives continuous self-replenishment, eliminating the need for external intervention or complex control systems to maintain optimal fluorine oil levels at the surface for toner releasability.

Inventive Principle:
Principle #25Self-service

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 solution enables the fixing rotating member to maintain excellent toner releasability for longer periods compared to conventional methods, effectively addressing the limitations of PFPE capacity and toner adhesion.

Implementation Method 1

a surface layer that contains a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA) and has pores with openings on an outer surface, wherein at least part of the pores contains a perfluoropolyether (PFPE)

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Data Source

PatentEP4020092B1Fixing rotating member, fixing apparatus, electrophotographic image forming apparatus, and method for producing fixing rotating member
Publication Date: 2025.02.19 CANON KK
  • EP4020092B1 patent drawingFigure 1A~2B
  • EP4020092B1 patent drawingFigure 3~4
  • EP4020092B1 patent drawingFigure 5

AI summary

A fixing rotating member comprising a base layer, an elastic layer and a surface layer, in this order, the surface layer containing PFA and PFPE, and having pores with openings at a first surface; at least part of the pores containing the PFPE, wherein when after removing the PFPE in the pores, placing a first observation region on the first surface, defining a ratio of a sum of areas of the openings in the first observation region relative to an area of the first observation region as P1; and placing a second observation region in a cross section of the surface layer, and defining a ratio of a sum of areas of the pores in the second observation region relative to an area of the second observation region as P2, P2/P1 is 1.3 or higher.