Fixing Device Heater Segmentation for Temperature Uniformity
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Solution Overview
Problem
Conventional fixing devices in image forming apparatuses face challenges in efficiently heating the fixing rotator to maintain uniform temperature across different sizes of recording media, leading to issues such as overheating and decreased productivity, especially when handling small and large sheets consecutively.
Innovation Solution
The implementation of a fixing device with a main heater and a sub-heater, where the sub-heater has a heat generation distribution with higher heat generation at the end portions for larger sheets and a uniform heat generation across the main heater, along with circuitry that determines the power usage based on the size of the recording medium to maintain the fixing rotator at the required temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single heater is used to heat the fixing rotator, then the device complexity is reduced, but the temperature uniformity across different sizes of recording media deteriorates
Solution Approach 1:
The heater is divided into multiple independent heating zones (first heating zone, second heating zone, third heating zone) along the circumferential direction of the fixing rotator. Each zone can be independently controlled to provide different heat generation amounts, enabling temperature uniformity across different recording media sizes while maintaining a relatively simple overall device structure.
Solution Approach 2:
Different regions of the heater are designed with different heat generation characteristics. The first heating zone generates higher heat for small recording media, while the second and third heating zones provide appropriate heat distribution for larger media. This local differentiation of heating properties ensures optimal temperature uniformity for various media sizes without requiring complete redesign of the heating system.
2Productivity
If the heater operates at high power to heat small recording media quickly, then the productivity is improved, but the overheating of the fixing rotator occurs
Solution Approach 1:
The heating system is segmented into multiple independently controllable zones. When small recording media are detected, only the first heating zone is activated at high power to rapidly heat the required region without unnecessarily heating other areas, thus improving productivity while preventing overheating of the entire fixing rotator.
Solution Approach 2:
The heater applies partial action by activating only the necessary heating zones based on the size of the recording media. For small media, only the first heating zone is used; for larger media, additional zones are activated. This prevents excessive heating of areas that do not require it, avoiding overheating while maintaining high productivity.
3Adaptability or versatility
If the heater is designed for maximum width media, then the adaptability to different media sizes is improved, but the heating efficiency for small media deteriorates
Solution Approach 1:
The heater is divided into multiple zones that can be selectively activated. When small recording media are used, only the first heating zone is activated, providing efficient heating without wasting energy on other zones. When larger media are used, the second and third heating zones are activated to ensure adequate heat coverage, thus maintaining heating efficiency across different media sizes while improving adaptability.
Solution Approach 2:
The heating system dynamically adjusts which zones are activated based on the detected size of the recording media. This dynamic configuration allows the heater to optimize its energy usage for each specific media size, preventing energy waste on unnecessary heating zones while ensuring adequate heat distribution for the actual media being processed.
4Stability of the object's composition
If the second heater has higher heat generation at end portions, then the temperature uniformity for large media is improved, but the energy consumption increases
Solution Approach 1:
The second heating zone is designed with non-uniform heat generation characteristics, with higher heat generation at the end portions corresponding to the edges of large recording media. This local quality differentiation ensures that areas requiring more heat (edges of large media) receive appropriate heating, improving temperature uniformity across the media surface while avoiding excessive energy consumption in areas that require less heat.
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 ensures efficient heating and reduced overheating, maintaining the fixing temperature uniformly across the fixing rotator, thereby enhancing productivity and preventing fixing failures, even under varying conditions such as low temperature environments and thick sheets.
Implementation Method 1
a first heater 102a and a second heater 102b The first heater 102a heats at least a region on the fixing rotator 101
Implementation Method 2
The second heater 102b heats a region on the fixing rotator 101 to heat a maximum recording medium 10P having a maximum width The second heater 102b has a heat generation distribution in which a heat generation amount of each of both end portions is larger than a heat generation amount of a center portion
Data Source
AI summary
A fixing device includes a fixing rotator, a first heater, a second heater, and circuitry. The first heater heats a region on the fixing rotator to heat a recording medium having a width smaller than a predetermined width. The second heater heats a region on the fixing rotator to heat a maximum recording medium used in the fixing device. The second heater has a heat generation distribution in which a heat generation amount of each of both end portions corresponding to both end portions of the maximum recording medium in a width direction of the recording medium is larger than a heat generation amount of a center portion. The circuitry determines whether to turn on the first heater and turn off the second heater or to turn on both the first heater and the second heater based on a required power to bring the fixing rotator to a fixing temperature.