Fixing Device Temperature Measurement for Scratch Detection
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Solution Overview
Problem
Existing fixing devices with resistance heating layers face challenges in accurately detecting scratches along the circumferential direction, leading to potential overheating and damage, as current temperature measurement methods may not capture localized high temperatures effectively, resulting in incomplete detection and potential damage to the pressing roller.
Innovation Solution
A fixing device with a temperature measuring unit that samples temperatures across multiple regions of the heating rotating body's surface, calculating the difference between maximum and minimum temperatures to determine abnormalities, such as scratches, allowing for precise detection and preventing damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If a resistance heating layer is used in a heating belt, then the warm-up time is short and energy consumption is reduced, but the heating belt may be damaged by scratches or foreign objects causing locally high temperatures
Solution Approach 1:
The heating belt surface is divided into multiple measurement regions, with each region monitored by a temperature sensor. This segmentation allows localized detection of temperature abnormalities, enabling early detection of scratches or foreign objects before they cause damage to the heating belt or pressing roller.
2Device complexity
If temperature measurement is performed using conventional methods, then the structure is simple, but localized high temperatures at scratch locations cannot be detected accurately
Solution Approach 1:
The temperature measurement system is segmented into multiple regions, with each region monitored by a dedicated temperature sensor. This allows precise detection of localized temperature abnormalities at scratch locations while maintaining a relatively simple overall structure.
Solution Approach 2:
Different regions of the heating belt are monitored with appropriate sensitivity to detect local temperature variations. The system focuses measurement precision on specific regions where abnormalities may occur, rather than requiring uniform high-precision measurement across the entire surface.
3Ease of operation
If conventional temperature detection is used, then the device is simple to operate, but scratches causing overheating and potential damage are not detected in time
Solution Approach 1:
The system automatically monitors temperature at multiple regions and compares measurements to detect abnormalities. The control unit autonomously identifies scratches or foreign objects based on temperature patterns, eliminating the need for manual inspection while maintaining simple operation.
Solution Approach 2:
The system continuously monitors temperature at multiple regions and provides feedback to the control unit. When temperature differences indicate a scratch or foreign object, the system can alert the operator or adjust heating parameters, ensuring reliable abnormality detection while maintaining ease of operation.
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 accurate detection of scratches and abnormalities, preventing overheating and damage to the pressing roller by identifying temperature differences indicative of scratch lengths, thus ensuring reliable operation and extending the lifespan of the heating device.
Implementation Method 1
The resistance heating layer produces Joule heat due to the current flowing along the direction of width
Implementation Method 2
Patent Literature 1 (Japanese Patent Application Publication No. 2000-227732) discloses a fixing device that controls the surface temperature of a heat roller heated by a heating means, such as a halogen heater, to be a predetermined temperature by detecting the surface temperature using an infrared sensor
Data Source
AI summary
A fixing device includes a temperature measuring unit, configured to measure the temperature in regions that extend partially along the outer surface of a heating rotating body, which includes a resistance heating layer, in the circumferential direction and are aligned in the direction of the axis of rotation of the heat rotating body, and a control unit configured to sample temperatures, measured by the temperature measuring unit in each of the regions, over the entire outer surface of the heating rotating body in the circumferential direction by causing the heating rotating body to rotate while supplying a predetermined amount of power to the resistance heating layer, and to determine whether an abnormality has occurred in the resistance heating layer based on the difference between the maximum temperature and the minimum temperature among the sampled temperatures in each region.