Fixing Belt Temperature Control via Thermal Expansion Tracking
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Solution Overview
Problem
Existing fixing devices in image forming apparatuses face challenges in controlling the temperature of the fixing belt to prevent overheating, which can lead to abrupt temperature rises and potential damage, especially in high-speed operations where the thermal capacity of the belt is low.
Innovation Solution
A fixing device with an endless fixing belt having multiple layers, an opposing rotator, a heater, and a contactless temperature sensor that detects the belt's temperature and stops heating when it reaches a predetermined level, ensuring the belt's outer face is within the sensor's viewing angle as it thermally expands, thereby preventing overheating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a contactless temperature sensor is used to detect fixing belt temperature, then overheating prevention is improved, but the sensor may fail to accurately detect temperature due to belt thermal expansion
Solution Approach 1:
The patent positions the contactless temperature sensor to track the dynamic thermal expansion of the fixing belt. As the belt expands radially when heated, the sensor's viewing angle is oriented such that the proportion of the belt's outer face within the detection range increases, ensuring continuous accurate temperature monitoring throughout the heating process
Solution Approach 2:
The patent explicitly accounts for the thermal expansion of the fixing belt by designing the sensor placement and viewing angle to accommodate radial expansion. The sensor is positioned and angled so that as the belt expands outward in the radial direction, more of its outer face remains within the detectable viewing angle, maintaining measurement precision despite dimensional changes
2Productivity
If the fixing belt has low thermal capacity for high-speed operation, then productivity is improved, but the risk of abrupt temperature rise increases
Solution Approach 1:
The patent implements a feedback control system where the contactless temperature sensor continuously monitors the fixing belt temperature and provides real-time data to the control unit. When the temperature reaches a predetermined threshold, the control unit automatically adjusts or stops heating, preventing abrupt temperature rises while maintaining high-speed operation capability through low thermal capacity belt design
Solution Approach 2:
The patent positions the contactless temperature sensor and establishes its viewing angle in advance to account for expected thermal expansion during operation. This preliminary configuration ensures that the sensor maintains accurate temperature detection capability throughout the heating process without requiring adjustment during operation, enabling safe high-speed processing
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 effectively prevents overheating of the fixing belt by ensuring the contactless temperature sensor can accurately detect temperature increases and halt heating when necessary, enhancing the safety and reliability of the image forming process.
Implementation Method 1
a heater (23) disposed inside the fixing belt (21) to heat the fixing belt (21)
Implementation Method 2
a contactless temperature sensor (27) disposed outside the fixing belt (21) and apart from an outer face (21d) of the fixing belt (21)... the contactless temperature sensor (27) is to detect a temperature of the fixing belt (21)
Implementation Method 3
The fixing belt (21) is to rotate and thermally expand... as the outer face (21d) of the fixing belt (21) shifts outward in the radial direction due to thermal expansion of the fixing belt (21)
Data Source
AI summary
A fixing device includes an endless fixing belt that is multilayered, an opposing rotator disposed opposite the fixing belt and pressed to the fixing belt to form a nip, a heater disposed inside the fixing belt, and a safety device including a contactless temperature sensor disposed outside the fixing belt and apart from an outer face of the fixing. The fixing belt is to rotate and thermally expand. The contactless temperature sensor detects a temperature of the fixing belt. The safety device stops heating by the heater when the temperature detected by the contactless temperature sensor is at or higher than a predetermined temperature. As the outer face of the fixing belt shifts outward in the radial direction due to thermal, a proportion of the outer face of the fixing belt in a viewing angle of the contactless temperature sensor increases.