Heating Belt Temperature Difference Detection for Image Forming Apparatus
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Solution Overview
Problem
Existing methods for detecting abnormalities such as breakage or positional deviation in heating belts of image forming apparatuses are inadequate, as they often require prolonged monitoring and may not accurately detect temperature changes, particularly when the heating belt meanders or develops wrinkles.
Innovation Solution
The implementation of a temperature difference detection circuit using thermistors at the R-side and F-side end portions of the heating belt, which compares the temperature differences to predetermined values using differential amplifier circuits and comparators to quickly identify abnormalities, allowing for immediate control of the heating process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If temperature monitoring is performed using a single temperature sensor at the end portion of the heating belt, then the device complexity is reduced, but the measurement precision and reliability of abnormality detection deteriorates
Solution Approach 1:
The heating belt temperature monitoring is segmented into multiple measurement points: temperature sensors are arranged at both end portions (R-side and F-side) of the heating belt, allowing independent temperature detection at each location. This segmentation enables comparison between different positions to detect abnormalities such as breakage or positional deviation that would be missed by a single sensor
Solution Approach 2:
Different locations on the heating belt are monitored with dedicated temperature sensors to capture local temperature variations. The R-side end portion temperature sensor detects temperature at one end, while the F-side end portion temperature sensor detects temperature at the other end, enabling localized abnormality detection and providing spatial information about temperature distribution
2Reliability
If temperature difference detection between multiple points is implemented, then the measurement precision and reliability of abnormality detection improves, but the device complexity increases
Solution Approach 1:
A temperature difference detection circuit serves as an intermediary component that automatically calculates the temperature difference between the R-side and F-side end portions. This intermediary device receives temperature signals from both sensors, performs the difference calculation, and outputs an abnormality detection signal, thereby simplifying the overall system architecture while maintaining high detection reliability
Solution Approach 2:
The manual or complex monitoring system is replaced with an automated electronic temperature difference detection circuit that uses electrical signals to detect temperature variations. The circuit automatically compares temperatures and generates abnormality signals, replacing what would otherwise require complex mechanical monitoring or manual inspection systems
3Reliability
If prolonged temperature monitoring is performed to ensure accurate detection, then the reliability of abnormality detection improves, but the loss of time and productivity deteriorates
Solution Approach 1:
The temperature difference detection circuit is pre-configured with reference temperature differences that represent normal operating conditions. By establishing these reference values in advance, the system can immediately detect abnormalities when actual temperature differences exceed the references, eliminating the need for prolonged monitoring periods to establish baseline behavior
Solution Approach 2:
The system skips the time-consuming process of prolonged temperature monitoring by directly comparing real-time temperature differences against pre-established reference values. This allows for immediate abnormality detection without requiring extended observation periods, thereby maintaining high reliability while minimizing time loss
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 rapid detection of breakage or positional deviation in the heating belt without prolonged monitoring, ensuring the safety and efficiency of the image forming apparatus by stopping the heating process when abnormalities are detected, and maintaining consistent temperature readings during normal operation.
Implementation Method 1
an R-side end portion thermistor for detecting the temperature of an R-side end portion of the heating belt and an F-side end portion thermistor for detecting the temperature of an F-side end portion of the heating belt
Implementation Method 2
a first differential amplifier circuit for detecting a first temperature difference that is obtained by subtracting the temperature of the other widthwise end portion from the temperature of the one widthwise end portion and a second differential amplifier circuit for detecting a second temperature difference that is obtained by subtracting the temperature of the one widthwise end portion from the temperature of the other widthwise end portion
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
An abnormality detection device for an image forming apparatus (1) detects an abnormality in the image forming apparatus (1) which includes a heating belt (83) looped around a heating roller (81) and a fixing roller (82). The abnormality detection device for an image forming apparatus includes (1): thermistors (86a, 86b) for detecting temperatures of one widthwise end portion (83a) and the other widthwise end portion (83b) of the heating belt (83); a temperature difference detection section (87a) for determining whether or not a temperature difference between the temperature of the one end portion (83a) and the temperature of the other end portion (83b) which are detected by the thermistors (86a, 86b) is greater than a predetermined value; and a judgment section (90) for judging that an abnormality has occurred in the image forming apparatus (1) when it is determined in the temperature difference detection section (87a) that the temperature difference is greater than the predetermined value.