Heating Belt Temperature Detection for Fixing Device Abnormality
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing image forming apparatuses using resistance heating layers in fixing devices face challenges in accurately detecting scratches or abnormalities, leading to potential overheating and damage, due to temperature variations and erroneous judgments caused by paper passing and non-paper passing regions.
Innovation Solution
The apparatus employs a temperature detection system with multiple measurement regions, calculating temperature differences to accurately identify abnormalities in the resistance heating layer, ensuring accurate judgment without being affected by temperature changes in paper-passing or non-paper-passing regions, and setting pairs of measurement regions to be non-adjacent for precise analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single temperature measurement region is used to detect abnormalities in the resistance heating layer, then the detection system is simple, but temperature variations caused by paper passing and non-paper passing regions lead to erroneous judgments
Solution Approach 1:
The heating belt surface is divided into multiple measurement regions (first through fourth regions) arranged in the width direction. Multiple temperature measurement devices are positioned to detect temperatures at different locations simultaneously, allowing the system to distinguish between normal temperature variations due to paper passage and actual abnormalities such as scratches in the resistance heating layer.
2Measurement precision
If temperature measurement is performed at multiple locations, then abnormality detection accuracy improves, but the device complexity and cost increase
Solution Approach 1:
The heating belt surface is divided into multiple measurement regions (first through fourth regions) arranged in the width direction. Multiple temperature measurement devices are positioned to detect temperatures at different locations simultaneously, allowing the system to distinguish between normal temperature variations due to paper passage and actual abnormalities such as scratches in the resistance heating layer.
Solution Approach 2:
Different measurement regions are positioned to monitor specific zones of the heating belt. The first and second measurement devices monitor regions that experience temperature changes during paper passage, while the third and fourth measurement devices monitor regions less affected by paper passage. This localized monitoring strategy enables accurate abnormality detection while managing system complexity.
3Area of stationary object
If measurement regions are positioned to cover the entire heating belt width, then comprehensive monitoring is achieved, but temperature variations from paper passing cause false abnormality detections
Solution Approach 1:
Different measurement regions are positioned to monitor specific zones of the heating belt. The first and second measurement devices monitor regions that experience temperature changes during paper passage, while the third and fourth measurement devices monitor regions less affected by paper passage. This localized monitoring strategy enables accurate abnormality detection while managing system complexity.
Solution Approach 2:
The measurement regions are asymmetrically positioned relative to the paper passage path. The third and fourth measurement regions are located where temperature variations due to paper passage are minimal, creating an asymmetric detection strategy that uses reference regions to compensate for variations in monitored regions, thereby improving detection accuracy.
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 or abnormalities in the resistance heating layer, preventing overheating and damage, and ensuring reliable operation by canceling out temperature variations caused by paper passage, thus enhancing the reliability of the fixing device.
Implementation Method 1
An alternating current is supplied to both ends of the resistance heating body provided in the heating belt... The resistance heating layer emits Joule heat when an electric current is supplied thereto.
Implementation Method 2
a temperature detection device (50) that detects a temperature of the heating belt (31)
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A fixing device, which thermally fixes an unfixed image on a recording sheet by causing the recording sheet to pass through a nip formed by a pressing member pressing against the outer circumferential surface of a heating belt that has a resistance heating layer, is provided with a temperature sensor 50 which measures temperatures of measurement regions that are set by sectioning the outer circumferential surface of the heating belt along the rotational axis. A control unit, during a printing operation, obtains a temperature difference between the maximum and minimum values of the measured temperatures for each measurement region based on the temperature distribution over the whole circumference of the outer circumferential surface of the heating belt, and judges whether an abnormality extending along the circumferential direction has occurred in the resistance heating layer by comparing the temperature difference between measurement regions of each pair (PxA8 and PxB8; PxA7 and PxB7; and the like), for each of the paper-passing region and the non-paper-passing region. This makes it possible to accurately and unerringly judge whether or not an abnormality such as a scratch has occurred in the resistance heating layer.