Fixing Device Nip Stability via Guide Positioning
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Solution Overview
Problem
Existing fixing devices in image forming apparatuses face challenges in maintaining stable nip formation and preventing deformation of components, leading to fluctuations in nip width and durability issues due to uneven pressure distribution and heat transmission.
Innovation Solution
The proposed fixing device incorporates a rotator, a belt, a nip forming member, an urging member, an upstream guide, and a downstream guide, where the nip forming member pinches the belt to form a nip, with the urging member ensuring stable pressure distribution and the guides positioned to prevent deformation and heat transmission, allowing for a convex shape to maintain nip pressure and reduce heat transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the upstream guide surface is positioned close to the rotation center to guide the belt effectively, then the belt guiding function is improved, but the nip width becomes unstable and components may deform due to excessive pressure
Solution Approach 1:
The patent positions the upstream guide surface in a direction perpendicular to the rotation axis, utilizing a spatial dimension separate from the radial direction. This allows the guide surface to effectively guide the belt without interfering with the nip formation zone, resolving the contradiction between guiding precision and nip stability.
Solution Approach 2:
The patent divides the guiding function into separate components: the upstream guide surface handles belt guidance, while the nip forming member handles pressure application. By segmenting these functions spatially, the system achieves both effective guiding and stable nip width without mutual interference.
2Reliability
If the downstream guide is positioned to prevent belt deviation, then the belt control function is improved, but heat transmission to the guide increases causing durability issues
Solution Approach 1:
The patent introduces a gap as an intermediary space between the downstream guide and the nip forming member. This gap prevents direct contact and heat transmission to the guide while still allowing the guide to control belt position, thus improving both reliability and durability.
Solution Approach 2:
The patent extracts the heat generation zone (nip forming member) from the guide structure (downstream guide), separating the functions of belt control and heat application. This extraction prevents heat from reaching the guide, eliminating the durability issue while maintaining belt control capability.
3Stability of the object's composition
If the nip forming member applies sufficient pressure to maintain stable nip, then the fixing function is improved, but unintended deformation of components occurs
Solution Approach 1:
The patent applies local quality by positioning the upstream guide surface at a specific location where it guides the belt without applying pressure. The pressure is localized only to the nip forming member in a different spatial region, allowing stable nip formation without deforming other components.
Solution Approach 2:
The patent creates a dynamic system where the upstream guide surface and downstream guide surface are positioned to work together with the nip forming member. The guides provide constraints that dynamically adjust to maintain nip stability while preventing component deformation through coordinated movement and positioning.
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 ensures stable and durable nip formation, prevents unintended deformation of components, and reduces heat transmission, enhancing the durability and efficiency of the fixing device by maintaining consistent nip pressure and preventing the belt from being caught by guides.
Implementation Method 1
an urging member configured to urge one of the rotator and the nip forming member towards the other in a particular direction perpendicular to the rotation axis
Implementation Method 2
the nip forming member is surrounded by the belt and configured to, with the rotator, pinch the belt to form a nip
Implementation Method 3
The upstream guide includes an upstream guide surface configured to guide an inner peripheral surface of the belt
Implementation Method 4
The downstream guide includes a downstream guide surface configured to guide the inner peripheral surface of the belt
Data Source
AI summary
A device includes a rotator having a rotation axis, a belt, a nip forming member surrounded by the belt and configured to, with the rotator, pinch the belt to form a nip, an urging member configured to urge one of the rotator and the nip forming member towards the other in a particular direction perpendicular to the rotation axis, an upstream guide and a downstream guide. The upstream guide includes an upstream guide surface configured to guide an inner peripheral surface of the belt. The nip forming member includes a facing surface which faces the rotator. An upstream edge of the facing surface in the moving direction is located at a position farther from the rotation axis, in the particular direction, than a downstream edge of the upstream guide surface.