Thermoplastic Elastomer Sheet Feeding Member for Charge Control
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Solution Overview
Problem
Conventional sheet feeding mechanisms in image forming apparatuses, such as laser printers, result in disturbed images due to insufficient removal of electric charges from sheets, as the surface potential of separation pads and sheet feed rollers is not adequately maintained at a lower level when repeatedly rubbed against sheets.
Innovation Solution
A thermoplastic elastomer composition comprising a polyurethane thermoplastic elastomer and a polyester thermoplastic elastomer, combined with an ion conductive agent like a quaternary ammonium salt or lithium salt/polyol, is used to create a sheet feeding member that effectively minimizes surface potential and prevents electric charge accumulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional separation pad made of crosslinked rubber is used, then the sheet feeding mechanism has good separation performance, but the material cannot be easily recycled and has high environmental impact
Solution Approach 1:
The patent changes the chemical composition parameters of the separation pad by using thermoplastic elastomer instead of crosslinked rubber, enabling recyclability while maintaining separation performance through optimized material properties
Solution Approach 2:
The patent uses a composite material system consisting of thermoplastic elastomer combined with specific additives (silica, titanium oxide, zinc oxide) to achieve both recyclability and effective sheet separation performance
2Device complexity
If the sheet feeding mechanism is simplified to reduce parts, then the device complexity and cost are reduced, but electric charges are not sufficiently removed from sheets causing disturbed images
Solution Approach 1:
The patent introduces ion conductive agents (quaternary ammonium salt or lithium salt/polyol) as intermediary substances in the separation pad to facilitate charge removal, enabling simplified mechanism design without compromising image quality
Solution Approach 2:
The patent changes the electrical properties of the separation pad by incorporating ion conductive agents, enabling sufficient charge removal even in simplified mechanisms with fewer components
3Duration of action of moving object
If the separation pad material is repeatedly rubbed against sheets, then the sheet feeding function is maintained, but the surface potential increases causing disturbed images
Solution Approach 1:
The separation pad materials have self-regenerating properties where the ion conductive agents continuously neutralize accumulated charges during operation, maintaining low surface potential throughout the service life
Solution Approach 2:
The patent modifies the electrical conductivity parameters of the separation pad through ion conductive agents, enabling the material to maintain stable surface potential characteristics during repeated use
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 sheet feeding member maintains a lower surface potential, preventing the formation of disturbed images by ensuring efficient discharge of electric charges, while also enhancing abrasion resistance and reducing the occurrence of multiple-sheet feeding and squeal issues.
Implementation Method 1
it has been found that the surface potential of the separation pad can be maintained at a lower level by blending a specific amount of ion conductive agent in a thermoplastic elastomer
Implementation Method 2
the separation pad is repeatedly rubbed against sheets to be electrically charged, and the accumulated electric charges are often released to the sheet
Data Source
AI summary
A sheet feeding member is provided, which is made of a thermoplastic elastomer composition comprising: a base polymer including a polyurethane thermoplastic elastomer and a polyester thermoplastic elastomer; and at least one ion conductive agent selected from the group consisting of a quaternary ammonium salt and a lithium salt/polyol, wherein the ion conductive agent is present in a proportion of 0.2 to 4 parts by mass based on 100 parts by mass of the base polymer in the thermoplastic elastomer composition.