Fixing Device Heat Distribution and First Print Time
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Solution Overview
Problem
Existing fixing devices in image forming apparatuses face challenges in quickly heating the fixing belt to shorten print time and overcoming heat shortages, especially with the use of a fixing film heated by a ceramic heater, which results in insufficient heating at the entry to the fixing nip, leading to faulty fixing.
Innovation Solution
The implementation of a fixing device with a tubular metal thermal conductor heated by a heater, where the heater is positioned inside the metal thermal conductor to heat an endless belt, and an alternative configuration where the endless belt is heated directly by the heater, along with a reflector to enhance heating efficiency and mechanical strength, and a heater pair with center and lateral end heaters that are turned on/off based on medium size and temperature detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If a fixing belt with small thermal capacity is used to shorten first print time, then heating speed is improved, but heat shortage occurs during high-speed conveyance
Solution Approach 1:
The fixing belt is preheated by the heater before the print job starts, so that when the first print occurs, the belt is already at the required temperature, thereby shortening the first print time without causing heat shortage during high-speed conveyance
Solution Approach 2:
The thermal capacity of the fixing belt is reduced to enable faster heating response, while the heater control parameters are adjusted to provide sufficient heat during high-speed operation, resolving the contradiction between fast heating and sustained heat availability
2Device complexity
If a fixing film heated by ceramic heater is used, then structure is simplified, but heating at entry to fixing nip becomes insufficient
Solution Approach 1:
The heater is positioned in a different spatial dimension (inside the fixing belt structure) to enable direct and uniform heating across the entire fixing belt surface, including the entry region, while maintaining structural simplicity
Solution Approach 2:
The fixing belt itself acts as an intermediary heat transfer medium, conducting heat from the heater uniformly across its surface to ensure adequate heating at the entry to the fixing nip while keeping the overall structure simple
3Temperature
If heater spans entire axial direction to heat fixing belt uniformly, then heating coverage is improved, but peripheral components overheat
Solution Approach 1:
The heater is designed with different heating zones or variable heating parameters across its span, providing focused heating where needed while reducing heat output in regions near peripheral components, thus achieving uniform heat distribution without causing peripheral overheating
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
These solutions effectively shorten the first print time, ensure consistent heat distribution, and save energy by efficiently heating the fixing belt, preventing overheating of peripheral components and maintaining the quality of the toner image.
Implementation Method 1
The heater 300 heats the metal thermal conductor 200 which in turn heats the endless belt 101, thus heating the endless belt 101 entirely
Implementation Method 2
A reflector is mounted on the support and interposed between the support and each of the first heat generator and the second heat generator to reflect light radiated from the first heat generator and the second heat generator toward the fixing rotator
Data Source
AI summary
A fixing device includes a first heat generator and a second heat generator that heat a fixing rotator. A support is disposed inside the fixing rotator. A reflector is mounted on the support and interposed between the support and each of the first heat generator and the second heat generator to reflect light radiated from the first heat generator and the second heat generator toward the fixing rotator. The reflector includes a body mounted on the support and a shield portion projecting from the body toward the first heat generator and the second heat generator to shield the fixing rotator from the first heat generator and the second heat generator. The shield portion includes a wing disposed opposite a non-conveyance span of the fixing rotator in the axial direction thereof where a recording medium is not conveyed over the fixing rotator.