Fuser Nip Release Mechanism Without Sensor Feedback
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Solution Overview
Problem
Traditional fuser assemblies in electrophotographic imaging processes require sensor feedback loops for nip release mechanisms, which increase costs and can lead to print defects due to permanent deformation of compliant layers under prolonged pressure.
Innovation Solution
A fuser assembly with a nip engagement and release apparatus that applies and decreases force without a sensor feedback loop, utilizing a combination of springs, a swing arm assembly, and a cam assembly to control the nip load, ensuring efficient pressure management between fuser structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a sensor feedback loop is used to control the nip release mechanism, then the precision of nip pressure control is improved, but the device complexity and cost increase
Solution Approach 1:
The mechanism uses the rotational direction of the heated member itself to trigger the nip release action, eliminating the need for external sensors and feedback systems. The system serves itself by using its own operational state (rotation direction) to control the pressure release mechanism.
Solution Approach 2:
The patent replaces the electronic sensor feedback system with a purely mechanical solution using a cam mechanism that responds to the rotational direction of the heated member. This mechanical substitution eliminates complex electronics while achieving the same functional result.
2Duration of action of stationary object
If the compliant layer is left under pressure for prolonged periods, then the fuser assembly maintains ready-to-use status, but permanent deformation occurs leading to print defects
Solution Approach 1:
The system implements periodic pressure application and release based on operational cycles. During non-use periods, the cam mechanism automatically releases the nip pressure, preventing permanent deformation while maintaining the ability to quickly reapply pressure when needed again.
Solution Approach 2:
The mechanism preliminarily releases pressure during non-use periods before permanent deformation can occur, yet maintains the capability for immediate pressure reapplication when operation resumes, ensuring both component protection and operational readiness.
3Reliability
If the nip release mechanism is activated during non-use, then permanent deformation is prevented, but the mechanism complexity increases
Solution Approach 1:
The patent combines the nip release function with the existing drive mechanism for the heated member. The same motor and drive train that control heating also control pressure application through the cam mechanism, merging multiple functions into a single integrated system.
Solution Approach 2:
The drive apparatus serves multiple functions: it rotates the heated member for heating, controls the timing of pressure application, and triggers the cam mechanism for pressure release. This multi-functionality eliminates the need for separate control systems.
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 solution reduces the likelihood of permanent deformation in fuser components, thereby preventing print defects and lowering costs by eliminating the need for sensor feedback systems, while maintaining effective nip pressure control.
Implementation Method 1
a spring in communication with the heated rotatable member and adapted to apply a force to the heated rotatable member
Implementation Method 2
a cam assembly including at least one cam element for positioning a nip-loading structure
Data Source
AI summary
A fuser assembly is provided comprising first and second fuser structures, drive apparatus and nip engagement and release apparatus. The first fuser structure comprises a heated rotatable member and first structure for supporting the heated rotatable member. The second fuser structure comprises a rotatable backup member positioned adjacent the heated rotatable member and second structure for supporting the backup member. The rotatable backup member is adapted to define a nip with the heated member. The drive apparatus is associated with one of the heated rotatable member and the backup member for effecting rotation of the one member in a selected first direction or a second direction. The nip engagement and release apparatus comprises nip-loading structure adapted to apply a sufficient force to one of the first and second support structures to achieve a desired nip load in response to the one member rotating in the first direction and decreasing the force to the one support structure to decrease the load at the nip in response to the one member rotating in the second direction. The nip engagement and release apparatus applies and decreases the force without the use of a sensor feedback loop.