Fixing Apparatus Belt Heater Segmentation for Thermal Efficiency
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Solution Overview
Problem
Existing fixing apparatuses with thin belts face issues in achieving uniform fixability, especially when dealing with large toner amounts or uneven surfaces, due to reduced heat transfer efficiency and thermal conductivity between the belt's surfaces, leading to poor fixability and uneven toner fusion.
Innovation Solution
A fixing apparatus with a cylindrical belt featuring multiple heaters, including a first and second heater positioned differently relative to the nip portion, and a control unit that adjusts the heat ratio between them based on process modes to ensure optimal heat distribution and temperature control, enhancing thermal efficiency and fixability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If a thin belt is used as a heating member, then warm-up time and power consumption are reduced, but heat transfer efficiency from the inner surface to the outer surface deteriorates
Solution Approach 1:
The belt is segmented into multiple independent heating zones with separate heaters along its length. This allows selective heating of specific zones, reducing overall warm-up time while maintaining heat transfer efficiency in active zones by avoiding unnecessary heating of inactive belt sections.
Solution Approach 2:
Different sections of the belt are equipped with different heating characteristics - some zones have higher thermal conductivity materials or closer heater spacing to compensate for the thin belt's overall reduced heat transfer efficiency, while other zones maintain the thin structure for rapid warm-up. This local differentiation resolves the contradiction between fast warm-up and sufficient heat transfer.
2Productivity
If the belt rotation speed is increased, then productivity is improved, but thermal flow supply to the belt surface deteriorates
Solution Approach 1:
The belt and recording material are pre-heated before entering the high-speed fixing zone. This preliminary heating ensures that even at high rotation speeds where thermal flow supply time is reduced, the material already has sufficient temperature for effective toner fixation.
Solution Approach 2:
The heating system dynamically adjusts heater power output based on detected belt speed. When the belt rotates faster, the control system increases heater power to compensate for reduced thermal flow supply time, maintaining adequate temperature for fixation despite higher productivity demands.
3Device complexity
If a single heater is used, then device complexity is reduced, but temperature distribution uniformity deteriorates
Solution Approach 1:
The heating system is divided into multiple independent heater segments distributed along the belt. Each heater can be independently controlled to provide precise temperature management in different zones, ensuring uniform overall temperature distribution while maintaining relatively simple individual heater components.
Solution Approach 2:
Temperature sensors are placed at multiple positions around the belt to detect local temperature variations. The control system uses this feedback information to adjust individual heater outputs, compensating for thermal gradients and ensuring uniform temperature distribution across the entire belt surface.
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 apparatus achieves improved fixability and thermal efficiency by optimizing heat distribution across the belt surface, ensuring effective toner image fixation on recording materials with varying grammage and surface types.
Implementation Method 1
a plurality of heaters disposed interior to the belt
Implementation Method 2
The elastic layer provided in the belt, however, decreases the heat transfer coefficient from the back surface to the front surface of the belt
Data Source
AI summary
The present disclosure is directed to enhance thermal efficiency of a fixing apparatus while a belt of the apparatus is heated, the fixing apparatus including: a belt including a plurality of heaters therein; a nip forming member that contacts with an inner surface of the belt; and a pressure member that forms a nip portion in conjunction with the nip forming member through the belt, wherein a ratio of an amount of heat generation by a heater farther from the nip portion to another heater closer to the nip portion is changed according to a speed at which a recording material is conveyed.