Flow-Coatable PFA Fuser Topcoat for Low Surface Energy
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Solution Overview
Problem
Conventional fuser members in electrophotographic printing devices face challenges in achieving a balance of low surface energy, flexibility, mechanical robustness, and thermal conductivity, with existing materials often compromising on one or more of these properties, and current flow-coatable fluororesin formulations are not stable for efficient topcoat application.
Innovation Solution
A method involving a dispersion of fluororesin, sacrificial polymeric binder, and solvent applied by flow coating, followed by specific heat treatment to form a uniform topcoat with desired properties, including low surface energy and mechanical robustness, using fluoroplastics like PFA and PTFE, with a sacrificial binder that stabilizes the dispersion and is removable without affecting the final topcoat.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If materials with low surface energy are used for topcoat, then good release properties are maintained, but mechanical strength is reduced
Solution Approach 1:
The patent uses composite materials by combining PFA fluororesin particles (providing low surface energy for release properties) with a sacrificial polymeric binder (providing mechanical strength during coating). The binder temporarily holds the fluororesin particles together during flow coating, and is later removed through thermal decomposition, leaving a mechanically robust PFA topcoat with the desired low surface energy characteristics.
Solution Approach 2:
The sacrificial polymeric binder acts as an intermediary material that enables the flow coating process. It provides the necessary viscosity and cohesion to the fluororesin particle dispersion during application, then is selectively removed through thermal decomposition at temperatures above 280°C, leaving behind the PFA topcoat with both mechanical integrity and low surface energy properties.
2Duration of action of stationary object
If materials with mechanical robustness are used for topcoat, then fuser member life is extended, but thermal conductivity is poor
Solution Approach 1:
The patent changes the physical and chemical parameters of the topcoat formulation by using a dispersion of fluororesin particles in a sacrificial binder system. This allows the coating to be applied at lower temperatures in a flow-coatable state, then thermally processed to remove the binder and sinter the fluororesin particles into a dense, thermally conductive structure that maintains mechanical robustness while improving thermal conductivity.
3Productivity
If PFA resin is flow coated from aqueous dispersion, then high transfer efficiency is achieved, but stable dispersion formulation is not available
Solution Approach 1:
The patent changes the rheological parameters of the dispersion by incorporating a sacrificial polymeric binder that provides appropriate viscosity and stability to the PFA fluororesin particle suspension. This binder prevents particle aggregation and settling during storage and application, enabling stable aqueous dispersions that can be successfully flow coated with high transfer efficiency.
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 method produces a fuser member with a smooth, uniform topcoat that maintains low surface energy, mechanical strength, and thermal conductivity, enhancing the fusing process efficiency and extending the fuser member's lifespan while reducing manufacturing costs.
Implementation Method 1
heating the topcoat to a second temperature ranging from about 285° C. to about 380° C. to form a uniform topcoat
Implementation Method 2
heating the topcoat to a first temperature ranging from a bout 100° C. to about 280° C.
Data Source
AI summary
Exemplary embodiments herein provide materials and methods for a fusing apparatus including a fuser member comprising a substrate and a topcoat layer, wherein the topcoat layer comprises a flow-coated fluororesin and has a surface energy of about 25 mN/m or less.