Fixing Belt Heating Unit Separation for Nip Zone Reliability
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Solution Overview
Problem
Conventional fixing devices face challenges in rapidly increasing temperature and improving fixing properties due to high thermal capacity of heating units and limited nip zone width, which affects high-speed image forming processes.
Innovation Solution
A fixing device with a separated nip zone and heating unit, where the heating unit is positioned adjacent to the fixing belt and not within the nip zone, allowing for increased nip zone width and reduced temperature rise time, using a nip spring with adjustable elasticity and a supporting roller to apply heat and pressure effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the heating unit is placed within the nip zone to apply heat and pressure simultaneously, then fixing properties are improved, but the heating unit is damaged due to pressurization and thermal deformation
Solution Approach 1:
The fixing device is divided into two separate functional zones: a heating unit that applies heat to the fixing belt outside the nip zone, and a nip zone that applies pressure to fix the toner image. This segmentation allows each component to perform its function without suffering from the combined stress of both heat and pressure, thereby improving both fixing properties and heating unit durability.
2Stability of the object's composition
If the heating unit has large thermal capacity to maintain stable temperature, then temperature stability is improved, but the period of time required to raise temperature increases
Solution Approach 1:
The heating unit is designed with localized heating capability, concentrating heat application to specific areas of the fixing belt rather than heating the entire belt uniformly. This allows for faster temperature rise in the critical heating zones while maintaining adequate temperature stability through controlled heat distribution to the nip zone.
3Reliability
If the nip zone width is increased to improve fixing properties, then heat transfer to toner images is improved, but the conventional roller-type structure limits the ability to increase nip zone width
Solution Approach 1:
The invention transitions from a conventional roller-to-roller contact structure to a belt-based structure where the fixing belt wraps around the nip zone. This dimensional change allows for a significantly wider nip zone width while maintaining the necessary pressure application, thereby improving heat transfer to toner images and fixing properties without the structural limitations of the roller-type design.
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 prevents heating unit damage, enables high-pressure application within the nip zone for improved fixing properties, and facilitates rapid temperature increase, enhancing high-speed printing capabilities.
Implementation Method 1
a heating unit, which is separated from the nip zone, to apply heat to the fixing belt
Implementation Method 2
a nip spring, which is elastically deformed, to form a nip zone at a contact area between the pressing roller and the fixing belt
Data Source
AI summary
A fixing device includes a fixing roller, a fixing belt which is made to rotate by a rotation force received from the fixing roller, a nip forming unit to form a nip zone at a contact area between the fixing roller and the fixing belt, and a first heating unit, which is separated from the nip zone, to apply heat to the fixing belt. The nip zone and the heating unit are separated, so that the heating unit can be prevented from being broken as a result of the pressurization and thermal deformation.