Non-conveyance Span Temperature Detector for Heating Device
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Solution Overview
Problem
In image forming apparatuses, thermistors used to detect temperature in fixing devices are prone to overheating due to direct contact with laminated heaters, requiring enhanced heat resistance and leading to increased manufacturing costs.
Innovation Solution
The implementation of a non-conveyance span temperature detector positioned opposite the pressure rotator, which detects the temperature of the pressure rotator in a non-conveyance span, reducing direct heat exposure and allowing for a less heat-resistant, cost-effective solution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the thermistor contacts the substrate of the laminated heater to detect the temperature, then the temperature detection accuracy is improved, but the thermistor is heated to high temperature easily requiring increased heat resistance
Solution Approach 1:
The temperature detection function is moved from the conveyance span (where the heating target passes) to the non-conveyance span (a different spatial dimension along the pressure rotator), allowing accurate temperature monitoring without direct exposure to the heated zone
Solution Approach 2:
The pressure rotator itself serves as an intermediary thermal conductor, allowing the thermistor to detect temperature indirectly through the pressure rotator's surface in the non-conveyance span, rather than directly contacting the laminated heater substrate
2Reliability
If the thermistor is positioned in the conveyance span to monitor heating process, then the temperature control during heating is improved, but the thermistor requires enhanced heat resistance and increases manufacturing cost
Solution Approach 1:
The detection position is shifted to the non-conveyance span, a different spatial location that still monitors the pressure rotator's temperature which reflects the heating process, avoiding the need for expensive heat-resistant thermistors
Solution Approach 2:
The pressure rotator's temperature in the non-conveyance span serves as a thermal copy or indicator of the overall system temperature state, allowing indirect monitoring without direct placement in the highest temperature zone
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 effectively suppresses temperature increase in the non-conveyance span, preventing overheating and reducing manufacturing costs while maintaining accurate temperature detection.
Implementation Method 1
A heater includes a heat generator that defines a conveyance span in an axial direction of the pressure rotator, where the heating target is conveyed
Implementation Method 2
The non-conveyance span temperature detector detects a temperature of the pressure rotator
Data Source
AI summary
A heating device includes an endless belt that rotates and a pressure rotator that rotates in a rotation direction. The pressure rotator contacts an outer circumferential surface of the endless belt to form a nip therebetween, through which a heating target having a particular width in an axial direction of the pressure rotator is conveyed. A heater includes a heat generator that defines a conveyance span in the axial direction of the pressure rotator, where the heating target is conveyed, and a non-conveyance span in the axial direction of the pressure rotator, where the heating target is not conveyed. A non-conveyance span temperature detector is disposed opposite the pressure rotator in the non-conveyance span of the heat generator. The non-conveyance span temperature detector detects a temperature of the pressure rotator.