Fixing Nip Pressure Control in Image Forming Apparatus
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Solution Overview
Problem
Existing image forming apparatuses face challenges in maintaining optimal nip pressure for fixing toner images on various sheet types, leading to issues such as crinkling and compromised conveying performance, due to the complexity and load-bearing limitations of existing nip pressure changing mechanisms.
Innovation Solution
A fixing unit with a nip pressure changing mechanism integrated into the apparatus main body, utilizing a cam and shaft system to adjust the pressure between heating and pressing rollers, allowing for automatic or manual control of nip pressure to accommodate different sheet types, thereby simplifying the fixing unit configuration and reducing load on the unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a nip pressure changing mechanism including cam and shaft is provided in the fixing unit, then the nip pressure can be adjusted for different sheet types, but the size and complexity of the fixing unit increase
Solution Approach 1:
The nip pressure changing mechanism (cam and shaft) is extracted from the fixing unit and relocated to the apparatus main body. This allows the fixing unit to maintain adaptability for different sheet types while reducing its own structural complexity and size.
Solution Approach 2:
The system is divided into two functional segments: the apparatus main body contains the nip pressure changing mechanism, while the fixing unit contains only the pressing roller and heating roller. This segmentation allows independent optimization of each component.
2Adaptability or versatility
If a nip pressure changing mechanism is provided in the fixing unit, then the nip pressure can be adjusted, but excessive load is applied to the fixing unit
Solution Approach 1:
The load-bearing cam and shaft mechanism is extracted from the fixing unit and placed in the apparatus main body, which has greater structural strength and load-bearing capacity. This prevents excessive load from compromising the fixing unit's integrity.
3Adaptability or versatility
If driving force is transmitted via gears from the apparatus main body to the shaft, then the nip pressure can be changed, but tooth jumping and malfunction occur due to excessive shaft torque
Solution Approach 1:
The shaft and gear transmission system is extracted from the fixing unit and relocated to the apparatus main body. This eliminates the risk of tooth jumping and malfunction by placing the high-torque components in a structure designed to handle such loads reliably.
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 solution enables flexible adjustment of nip pressure to ensure proper image fixation on diverse sheet types, reduces the risk of crinkling, and enhances the stability and cost-effectiveness of the fixing unit by minimizing component complexity and load-bearing stress.
Implementation Method 1
The first rotating member is heated by a heating source
Implementation Method 2
a compression spring for making the pressing roller pressed to a heating roller
Data Source
AI summary
An image forming apparatus includes a fixing unit and an apparatus main body. The fixing unit includes a first rotating member, a second rotating member and a fixing nip forming mechanism. The first rotating member is heated by a heating source. The second rotating member faces to the first rotating member. The fixing nip forming mechanism makes the second rotating member pressed to the first rotating member and forms a fixing nip between the first rotating member and second rotating member. To the apparatus main body, the fixing unit is attachably/detachably installed. The apparatus main body includes a nip pressure changing mechanism. The nip pressure changing mechanism presses the fixing nip forming mechanism and changes a pressure of the fixing nip.