Fixing Device Pressure Mechanism for Stable Nip Contact
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Solution Overview
Problem
Existing fixing devices in electrophotographic image forming apparatuses face challenges in maintaining consistent and stable contact pressure between the heating and pressure members, which affects the fixation of toner images on recording media.
Innovation Solution
A pressure mechanism comprising a pressure plate, biasing member, cam member, and support member is used to adjust the contact pressure of the fixing nip portion, allowing for stable pressure application between the heating and pressure members, with the support member enhancing dimensional accuracy and adjustability independently of the fixing frame.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a pressure mechanism is integrated into the fixing frame, then the overall structure becomes more compact, but the dimensional accuracy and adjustability of the pressure mechanism are affected by the fixing frame's dimensional variations
Solution Approach 1:
The pressure mechanism is separated from the fixing frame into an independent modular unit. This segmentation allows the pressure mechanism to be manufactured and adjusted independently, ensuring high dimensional accuracy without being affected by the fixing frame's dimensional variations, while still achieving a compact overall structure through modular integration.
2Adaptability or versatility
If the pressure mechanism is made adjustable for different paper types, then adaptability improves, but the mechanism becomes more complex
Solution Approach 1:
The pressure mechanism incorporates adjustable components that allow dynamic modification of pressure parameters according to different paper types and thicknesses. This dynamic adjustability is achieved through simple mechanical means such as adjustable springs or cam mechanisms, providing versatility without significantly increasing overall mechanism complexity.
3Ease of operation
If the pressure plate is designed to swing for pressure adjustment, then ease of operation improves, but the reliability of consistent pressure application may be affected
Solution Approach 1:
The pressure plate utilizes a cam-shaped member with a curved profile that converts rotational motion into controlled swinging motion. This curved geometry ensures that the pressure plate swings to precise, repeatable positions, maintaining consistent pressure application while allowing easy adjustment through simple rotational movement of the cam member.
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 configuration stabilizes contact pressure between the heating and pressure members, ensuring consistent fixation of toner images while allowing for a compact, low-cost, and simple design.
Implementation Method 1
The biasing member biases the pressure plate in an approaching direction with respect to one of the heating member (32) and the pressure member (33)
Implementation Method 2
The cam member (43) contacts the pressure plate (41) on a side opposite to the biasing member (42), and rotates to cause the pressure plate (41) to swing
Implementation Method 3
applies heat and pressure to the recording medium to have the unfixed toner image fixed onto the recording medium
Implementation Method 4
The pressure member contacts the heating member and has pressure applied thereto to form the fixing nip portion
Data Source
AI summary
A fixing device includes a heating member, a pressure member, a pressure mechanism, and a fixing frame. The pressure mechanism includes a pressure plate, a biasing member, a cam member, and a support member. The pressure plate swings in an approaching direction and a separating direction with respect to one of the heating member and the pressure member. The biasing member biases the pressure plate in the approaching direction with respect to one of the heating member and the pressure member. The cam member contacts the pressure plate on a side opposite to the biasing member and rotates to cause the pressure plate to swing. The support member is secured to the fixing frame and supports one end of the biasing member and a swing fulcrum of the pressure plate. The support member has a through hole in which a rotation axis of the cam member is inserted.