Fixing Device Slide Sheet Reduces Belt Fatigue
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Solution Overview
Problem
Existing fixing devices in image forming apparatuses face issues with fatigue rupture of the endless belt due to excessive bending stress, particularly when the number of fixed sheets exceeds a certain limit, leading to premature wear and potential failure.
Innovation Solution
The proposed fixing device incorporates a slide sheet with a longer length from one end portion to the other than the path between the first and second fixing portions on the attachment member, which creates a slack that is restricted by a restriction member, minimizing the bending stress on the endless belt and preventing fatigue rupture by ensuring the slack is only at the downstream side of the contact region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the endless belt is used in a conventional fixing device, then the fixing function is achieved, but the endless belt suffers from fatigue rupture due to excessive bending stress when processing a large number of sheets
Solution Approach 1:
The patent introduces a slide sheet as an intermediary component between the attachment member and the endless belt. This slide sheet absorbs the bending stress through its longer length creating controlled slack, protecting the endless belt from excessive stress while maintaining the fixing function. The slide sheet acts as a mediator that takes on the mechanical stress that would otherwise be transmitted to the endless belt.
2Reliability
If the slide sheet length is increased to create slack, then the bending stress on the endless belt is reduced, but the device complexity increases
Solution Approach 1:
The patent employs a flexible slide sheet with a specific length greater than the attachment member path to create controlled slack. This flexible component absorbs bending stress through its ability to deform and create slack, protecting the endless belt without requiring complex rigid structures or additional mechanical components.
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 design significantly increases the resistance to fatigue rupture, allowing the fixing device to handle a higher number of fixed sheets without failure, as demonstrated by the ability to reach 1000 kPV without fatigue issues, compared to conventional designs which fail around 300 kPV.
Implementation Method 1
a heat source that heats the endless belt
Implementation Method 2
a pressure roller that presses the outer surface of the endless belt to the attachment surface
Data Source
AI summary
A fixing device includes a heat assembly including an endless belt, a heat source, an attachment member having an attachment surface and first and second side surfaces, and a slide sheet having first and second end portions that are respectively fixed to a first fixing portion at the first side surface and a second fixing portion at the second side surface, the slide sheet having a larger length from the first end portion to the second end portion than a length of a path of the attachment member extending from the first fixing portion to the second fixing portion through the first side surface, the attachment surface, and the second side surface; and a pressure roller that presses the outer surface of the endless belt to the attachment surface.