Fixing Film Unit Structure to Prevent Bulging and Misalignment
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Solution Overview
Problem
The existing fixing apparatuses using a film heating method suffer from deformation of the fixing film due to separation of the pressure stay and heater holder, leading to bulging and potential misalignment, which affects the fixing process.
Innovation Solution
A fixing apparatus is designed with a tubular film, a guide member, a stay member, and a restriction structure to reinforce the guide member, and a roller forms a fixing nip portion, with the restriction structure preventing movement of the guide member and stay member from separation, thereby stabilizing the film's rotation and reducing deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the pressure stay and heater holder are not fixed to each other near the center of the film unit, then the film unit can be easily assembled and replaced, but the pressure stay and heater holder may separate and bulge out, causing film deformation
Solution Approach 1:
The heater holder is divided into a first heater holder portion and a second heater holder portion that can be assembled together. The pressure stay is divided into a first pressure stay portion and a second pressure stay portion. This segmentation allows for easy assembly and replacement while providing multiple fixed points to prevent bulging and maintain component position stability.
Solution Approach 2:
The first heater holder portion and second heater holder portion are merged to form a complete heater holder structure. Similarly, the first and second pressure stay portions are merged to form a complete pressure stay. This merging provides structural continuity and prevents separation bulging while maintaining ease of assembly through modular design.
2Ease of manufacture
If the film is loosely fitted around the heater holder, then the film can be easily installed and replaced, but the film may deform and bulge out when the heater holder bulges
Solution Approach 1:
The film is pre-formed into a tubular shape with a circular cross section before installation. This preliminary shaping ensures that the film maintains its form and does not deform or bulge out, even when the heater holder experiences minor displacements, while still allowing for easy installation.
3Productivity
If the pressure roller rotates the fixing film, then the film conveys the recording medium effectively, but the film may wrap around the pressure roller and cause misalignment
Solution Approach 1:
The restriction structure provides continuous feedback to control the film's position and wrapping around the pressure roller. This ensures that the film maintains proper alignment during rotation and conveyance, preventing misalignment while maintaining effective conveyance of the recording medium.
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 effectively suppresses film deformation, ensuring consistent and reliable fixing of toner images onto recording media by maintaining the film's shape and alignment, even under varying sheet sizes and conditions.
Implementation Method 1
a heater 54, a tubular film (fixing film) 53... The heater 54 fitted in the heater holder 55 is positioned between the heater holder 55 and the fixing film 53
Implementation Method 2
The pressure roller 52 includes a metal core 52a, an elastic material layer 52b made of, for example, silicone rubber
Implementation Method 3
the pressure roller 52 moves the fixing film 53 due to the friction between the pressure roller 52 and the outside surface of the fixing film 53
Data Source
AI summary
A fixing apparatus includes a film, a guide member, a stay member, a roller, and a restriction structure. The guide member is disposed in an inside space of the film, elongated in a generatrix direction of the film, and guides rotation of the film. The stay member reinforces the guide member, the film and a roller form a fixing nip portion between the film and the roller, and a recording medium having a toner image is heated to fix the toner image at the fixing nip portion while a sheet passes through the fixing nip portion. The roller is disposed in contact with an outside surface of the film. The restriction structure restricts movement of the guide member in a direction orthogonal to the generatrix direction of the film and also in a direction in which the stay member and the guide member are separated from each other.