Contact Roller with Spiral Grooves and Variable Nip Pressure
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Solution Overview
Problem
Existing contact rollers fail to prevent wrinkles and air layers in rolled films, and can cause scratches or cracks when films are thinned and rolled at high speeds due to tension fluctuations between the rubber roll main body and spiral rubber layers.
Innovation Solution
A contact roller design featuring a cylindrical rubber roll with two spiral groove groups and surface rubber layers, where the spiral rubber layers have lower hardness than the main body, and a surface rubber layer with a higher nip pressure than both, to evenly distribute tension and prevent film damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a rubber roll with spiral rubber layers is pressed against a take-up roll with a film sandwiched therebetween, then the grip force to the film is improved and wrinkles are prevented, but tension fluctuation is generated on the boundary between the rubber roll main body and the spiral rubber layers
Solution Approach 1:
The invention applies local quality by creating a surface layer with different friction characteristics than the underlying spiral rubber layers. The surface layer has a friction coefficient closer to that of the film than the spiral rubber layers, which have higher friction. This gradient structure prevents sudden tension fluctuations at the boundary while maintaining high grip force through the spiral rubber layers, thereby preventing both wrinkles and surface defects.
2Productivity
If the film is thinned and the take-up roll is rotated at high speed, then productivity is improved, but the influence of tension fluctuation becomes large causing scratches or cracks in the film surface
Solution Approach 1:
The invention changes the friction parameter gradient from the surface to the core of the rubber roll. By making the surface layer have a friction coefficient closer to the film than the underlying spiral rubber layers, the invention creates a gradual transition that prevents sudden tension changes. This allows high-speed rotation of thinned films without generating harmful tension fluctuations that would cause scratches or cracks.
3Device complexity
If merely pressing a film on a take-up roll by a contact roller is used, then the structure is simple, but it is not possible to fully prevent the creation of wrinkles and the formation of air layers
Solution Approach 1:
The invention uses composite material structure by combining a rubber roll main body with spiral rubber layers having different properties. The spiral rubber layers have lower hardness and higher friction coefficient than the main body, creating a composite structure that generates both nip pressure and tension. This composite approach fully prevents wrinkles and air layer formation while maintaining reasonable structural complexity.
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
Prevents wrinkles and air layers, maintains film quality by reducing scratches and improving package density and dimensional accuracy, even at high speeds, and extends the life of the contact roller by reducing wear and degradation.
Implementation Method 1
The nip pressure of a surface of the surface rubber layer, which corresponds to the rubber roll main body, is higher than the nip pressure of the surface of the surface rubber layer, which corresponds to the spiral rubber layers
Implementation Method 2
The spiral rubber layers filled in the grooves have hardness lower than that of the rubber roll main body, and have a higher coefficient of friction. Therefore, the grip force of the spiral rubber layers to the film pinched between the take-up roll and the rubber roll is higher as compared to that of the rubber roll main body
Implementation Method 3
With this structure, due to the difference in nip pressure between the spiral rubber layers and the rubber roll main body, a tension is generated towards right and left ends of the rubber roll
Data Source
AI summary
A contact roller according to one embodiment includes a cylindrical rubber roll main body, two spiral groove groups provided in a surface of the rubber roll main body, spiral rubber layers which is provided in the groove groups and hardness of which is lower than the rubber roll main body, and a surface rubber layer which covers a surface of the rubber roll main body and hardness of which is lower than that of the rubber roll main body. Nip pressure of the surface rubber layer corresponding to the rubber roll main body is higher than that of the surface rubber layer corresponding to the spiral rubber layers.