Fixing Unit Nip Load Release Mechanism
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Solution Overview
Problem
Existing image forming apparatus fixing units require excessive operating force to release a paper jam, which can be harmful to users and hinder miniaturization due to the complexity and cost of the mechanisms used to reduce this force.
Innovation Solution
A fixing unit design where the pressure conveyance member is supported at an intermediate position, with one end of the support members contacting pressure springs and the other end contacting nip load releasing units, allowing for reduced operating force through the use of stoppers and rotary support shafts that facilitate easier release of the nip load without increasing the number of parts or cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If an eccentric cam driving unit is used to automatically move the frame engaging with the pressure belt or pressure roller, then the nip load can be released automatically, but the number of parts increases and the apparatus size and cost increase
Solution Approach 1:
The patent extracts the automatic release function from a complex eccentric cam driving unit and implements it through a simpler mechanism involving a release lever that directly acts on the pressure arm. This removes unnecessary components while maintaining the automatic release capability when the release lever is actuated.
Solution Approach 2:
Instead of using a complex automatic actuation mechanism, the patent inverts the approach by providing a simple manual release lever that the user operates directly. This inversion simplifies the mechanism while still achieving the release function, trading automaticity for simplicity.
2Device complexity
If a lever is provided to come in contact with a member engaging with the pressure belt or pressure roller to release the nip load, then the structure is simple, but excessive operating force is required
Solution Approach 1:
The patent segments the force transmission path by introducing a support member with a fulcrum point. The release lever does not directly pull the pressure arm but instead pivots around the fulcrum, using mechanical advantage to amplify the user's operating force and reduce the force required to release the nip load.
Solution Approach 2:
The patent introduces dynamic mechanical advantage through the fulcrum-based lever system. The support member rotates around the fulcrum point, transforming the user's small operating force into a larger release force that overcomes the pressure spring load, making the operation easier while maintaining structural simplicity.
3Ease of operation
If the operating lever length is increased to reduce operating force, then the operating force decreases, but the apparatus size increases
Solution Approach 1:
The patent uses a dynamic fulcrum-based lever system where the support member rotates around a fixed fulcrum point. This dynamic mechanism provides mechanical advantage without requiring a long lever arm, as the rotation around the fulcrum amplifies force effectively within a compact space, avoiding apparatus size increase.
Solution Approach 2:
The support member acts as an intermediary between the release lever and the pressure arm. Instead of directly extending the lever arm length, the support member mediates the force transmission through rotation around the fulcrum, providing mechanical advantage while maintaining a compact overall structure.
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 design reduces the operating force required to release a paper jam, making the process user-friendly and cost-effective while maintaining a compact apparatus size, with the operating force being significantly lower than in previous systems.
Implementation Method 1
pressure springs which can apply a predetermined load to the pressure conveyance member through the support members respectively so as to press the pressure conveyance member toward the heating member
Implementation Method 2
a heating member including a heating element such as a heater
Implementation Method 3
Toner is fused by heat from the heater 5
Implementation Method 4
The pressure belt 2 rotates with the heating roller 1 due to the rolling friction of the heating roller 1
Data Source
AI summary
A fixing unit where an operating force for releasing a nip can be reduced with a small-sized configuration. The fixing unit has a heating roller including a heating element, a pressure belt, pressure arms, pressure springs, and nip load releasing units. The pressure belt is supported in an intermediate position between the pressure arms 3. One end portions of the pressure arms are brought into contact with the pressure springs respectively. The other end portions of the pressure arms are brought into contact with the nip load releasing units respectively. When a load applied to the pressure belt is released by the nip load releasing units, the other end portions of the pressure arms move away from the heating roller.