Silicone Rubber Coating for Developing Roll Surface Roughness
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Solution Overview
Problem
Existing rubber coating layers for developing rolls in image forming apparatuses face challenges in achieving a uniform rough surface, maintaining flexibility, avoiding rubber substrate effects, and ensuring non-tackiness and low friction, while also preventing toner damage and stress.
Innovation Solution
A rubber coating layer composition comprising a polyol, an isocyanate compound, reactive silicone oil, and silicone rubber particles with specific hardness and particle size, applied to form a coating layer that maintains a certain thickness and surface roughness, ensuring the silicone rubber particles are evenly distributed and aggregated to achieve the desired properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If hard resin particles are used to form a rough surface on the developing roll, then surface roughness is improved, but the coating layer becomes hard and projected parts become hard causing toner deterioration
Solution Approach 1:
The invention changes the material parameter from hard resin particles to silicone rubber particles with specific hardness (JIS A 30-90 degrees) and controls particle diameter (1-10 μm) to achieve the desired surface roughness while maintaining flexibility and preventing toner deterioration
Solution Approach 2:
The invention uses a composite coating layer comprising silicone rubber particles dispersed in a binder, combining the roughness-providing capability of particles with the flexibility and toner-protection properties of the binder matrix
2Strength
If the coating layer thickness is increased to maintain flexibility, then flexibility is improved, but the roughness effect of particles is reduced
Solution Approach 1:
The invention optimizes the particle diameter to be 1/10 to 1/3 of the coating layer thickness, ensuring that particles remain exposed on the surface to provide roughness while the coating layer maintains sufficient thickness for flexibility and toner protection
3Productivity
If the developing roll rotates at high speed, then productivity is improved, but frictional heat increases causing toner melting and filming
Solution Approach 1:
The invention converts the frictional heat that would normally cause toner melting into a beneficial effect by using silicone rubber particles with low friction coefficient to reduce overall friction, and by utilizing the heat-resistant properties of silicone rubber to withstand the frictional heat without deteriorating
Solution Approach 2:
The invention uses silicone rubber particles that can withstand frictional heat and wear, providing a durable coating that maintains its properties even under high-speed rotation conditions
4Strength
If silicone rubber particles with low hardness are used to maintain flexibility, then flexibility is improved, but the ability to provide sufficient surface roughness is reduced
Solution Approach 1:
The invention specifies silicone rubber particle hardness within the range of JIS A 30-90 degrees and particle diameter of 1-10 μm, optimizing both flexibility and surface roughness properties simultaneously
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 solution provides a rubber coating layer with a uniform rough surface, maintaining flexibility and preventing toner damage, while achieving non-tackiness and low friction, thus enhancing the durability and performance of the developing roll in image forming apparatuses.
Implementation Method 1
silicone rubber particles which have a hardness (JIS K6253: 1997) by Durometer A, measured instantaneously, of 20 to 80 degrees and an average particle diameter of 0.2 to 10 μm are evenly distributed and aggregated
Implementation Method 2
a liquid binder containing at least a polyol, an isocyanate compound and reactive silicone oil
Implementation Method 3
a liquid binder containing at least a polyol, an isocyanate compound and reactive silicone oil
Implementation Method 4
coating a coating layer composition around a developing roll having a rubber substrate layer and curing the coating layer composition
Data Source
Figure 1~2
Figure 3
AI summary
An object is to provide a rubber member for coating a developing roll which is formed a uniform rough surface at a surface of the developing roll, does exert neither damage nor toner stress to the mating member or the toner while maintaining flexibility, is possible to secure a thickness which can sufficiently avoid the effect of the rubber, and can realize non-tackiness and low friction, which can be solved by a rubber member for coating a developing roll which is the rubber member for coating a developing roll obtained by coating a coating layer 13 component at around a developing roll having a rubber substrate layer 12 and curing the same, wherein the coating layer 13 component comprises a liquid binder which contains at least a polyol, an isocyanate compound and reactive silicone oil, silicone rubber particles 101 having a hardness (JIS K6253: 1997) by Durometer A (instantaneous) of 20 to 80 degree and a rubber particle size of 0.2 to 10 µm, and a diluting solvent, and a ratio of a thickness of the coating layer 13 after curing and a diameter of the rubber particles 101 satisfies rubber particles 101 diameter/coating layer 13 thickness<0.3.