Foamed Silicone Rubber Fixing Roller Production
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Solution Overview
Problem
The production of foamed silicone rubber for fixing pressure rollers faces issues with interfacial delamination and reduced rubber strength due to large bubbles forming near the metallic core, especially when there is a long time between extrusion and primary vulcanization, leading to unstable foaming conditions.
Innovation Solution
A method involving molding unvulcanized silicone rubber with a chemical foaming agent under reduced pressure, followed by a leaving step where the molded product is allowed to stand for a predetermined time before vulcanization, to prevent abnormal foaming and ensure a uniform foamed silicone rubber layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If primary vulcanization is performed after a long time between extrusion and primary vulcanization, then the production process allows flexibility in timing, but large bubbles generate in the vicinity of the metallic core causing interfacial delamination and reduction in rubber strength
Solution Approach 1:
The patent applies parameter changes by controlling the leaving time between extrusion and primary vulcanization to be 3 to 72 hours, and by setting the secondary vulcanization temperature to 200°C or higher. This specific parameter range prevents abnormal foaming while allowing production flexibility, resolving the contradiction between time loss and interface stability.
2Productivity
If primary vulcanization is performed immediately after extrusion by means of a vent-type extruder, then production efficiency is improved, but no foaming attributed to a chemical foaming agent occurs which is also problematic
Solution Approach 1:
The patent applies preliminary action by incorporating a chemical foaming agent into the unvulcanized silicone rubber before extrusion. The foaming agent remains dormant during extrusion and venting, then activates during the controlled leaving period and secondary vulcanization, ensuring uniform foaming while maintaining production efficiency.
3Ease of manufacture
If a chemical foaming agent is incorporated into unvulcanized silicone rubber and the material is molded under reduced pressure, then foaming can occur, but large bubbles form near the metallic core causing interfacial delamination when leaving time is extended
Solution Approach 1:
The patent resolves this contradiction by precisely controlling two parameters: the leaving time (3 to 72 hours) and the secondary vulcanization temperature (200°C or higher). This parameter control enables the chemical foaming agent to generate uniform fine bubbles rather than large bubbles, preventing interfacial delamination while maintaining ease of manufacture.
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 approach prevents interfacial delamination and maintains rubber strength, allowing for the production of a fixing pressure roller with a wide fixation width and enhanced toner fixability, while avoiding the formation of large bubbles near the metallic core.
Implementation Method 1
Such foamed silicone rubber is generally produced via a chemical foaming process, in which a foaming agent is incorporated in advance into a base rubber, and the foaming agent is gasified through heating.
Implementation Method 2
after the leaving step, a foam-curing step of vulcanizing the unvulcanized silicone rubber
Data Source
AI summary
To provide a fixing pressure roller production method which can readily provide a fixing pressure roller in which no abnormal foaming occurs at the interface between the elastic layer and the metallic core. The method of the present invention includes a molding step of molding, under reduced pressure, an unvulcanized silicone rubber containing a chemical foaming agent; after the molding step, a leaving step of allowing the molded product to stand for a predetermined period of time; and after the leaving step, a foam-curing step of vulcanizing the unvulcanized silicone rubber, to thereby yield an elastic layer formed of a foamed silicone rubber.