Cracked Resin Layer on Solid Rubber Pressure Roller
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Solution Overview
Problem
In image forming apparatuses, belt-type fixing devices with solid rubber pressure rollers face issues of uneven pressure distribution, tackiness leading to adhesion, and durability problems due to low hardness, which result in image quality defects and assembly challenges, especially when using a resin layer without adequate support for the elastic layer's transformation.
Innovation Solution
A pressure roller with an elastic layer made of solid rubber and a resin layer, where a plurality of cracks are formed on the resin layer to allow for deep penetration and support the elastic layer, reducing stress concentration and preventing crack generation during pressure application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a resin layer is formed on the pressure roller surface to improve sliding properties, then sliding between the fixing belt and pressure roller is improved, but the resin layer cracks under pressure in the nip portion
Solution Approach 1:
The resin layer is segmented by forming cracks beforehand in a controlled pattern. These pre-formed cracks divide the resin layer into multiple segments that can flex independently under pressure, preventing the formation of large damaging cracks while maintaining surface sliding properties.
Solution Approach 2:
Cracks are formed in advance in the resin layer before the pressure roller is put into service. These pre-formed cracks act as stress relief features that absorb and distribute the mechanical stress encountered during operation, preventing sudden catastrophic failure of the resin layer.
2Ease of operation
If the elastic layer hardness is reduced to lower transformation, then sliding property is improved, but tackiness increases causing adhesion between the fixing belt and pressure roller
Solution Approach 1:
The pressure roller surface has non-uniform properties: the elastic layer provides localized compliance and pressure distribution, while the resin layer provides localized low-friction sliding surface. This local quality differentiation allows the roller to exhibit both good sliding properties and controlled transformation without excessive tackiness.
Solution Approach 2:
The pressure roller uses a composite structure combining an elastic layer (solid rubber or silicone rubber) with a resin layer (PTFE or PFA). The elastic layer provides cushioning and pressure distribution, while the resin layer provides low-friction sliding surface, creating a material composite that balances sliding properties and tackiness control.
3Productivity
If the elastic layer hardness is reduced to secure wide nip portion, then fixing speed is improved, but pressure distribution becomes uneven causing image quality decline
Solution Approach 1:
The pressure roller creates localized quality variation in pressure distribution through its composite structure. The elastic layer deforms locally to conform to the fixing belt and recording material surface, ensuring uniform pressure distribution in the nip region while maintaining overall low hardness for wide nip portion and high fixing speed.
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 ensures that the resin layer does not crack under pressure, maintaining the integrity of the elastic layer, improving sliding properties, reducing noise and damage, and enhancing the assembly efficiency of the fixing device while maintaining image quality.
Implementation Method 1
a plurality of cracks are formed on the resin layer so as to be substantially deep enough to arrive at the elastic layer
Implementation Method 2
a solid rubber layer is squeezed by high load, and a surface of the solid rubber shrinks once before entering the nip portion, and then is extended gradually as the pressure in the nip portion increases
Implementation Method 3
it is necessary for the inner surface of the fixing belt to slide on the surface of the pressure roller in the nip portion. However, if a tack property is high, both of them cannot slide easily on each other
Data Source
AI summary
A belt-type fixing device having therein a pressure roller that has an elastic layer which is made of solid rubber, wherein, the elastic layer is covered by a resin layer on which a plurality of cracks are formed to be substantially deep enough to arrive at the elastic layer, and cracks harmful for the elastic layer are not caused by pressurization at a nip portion.