Fixing Equipment Temperature Control Using Multiple Detection Elements
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Solution Overview
Problem
Conventional image forming apparatuses face issues with inaccurate temperature detection and abnormal heating due to broken temperature detection elements or disconnected connectors in the fixing equipment, leading to safety concerns and inefficient temperature control.
Innovation Solution
The implementation of a control system that uses multiple temperature detection elements, including thermistors and thermopiles, to accurately monitor the temperature of the heat roller and detect any connection issues or element failures, with a wired-OR circuit to automatically adjust heating conditions and prevent overheating by controlling the halogen lamps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single temperature detection element is used in the fixing equipment, then the device complexity is reduced, but the reliability of temperature control deteriorates because the element may break or disconnect causing abnormal heating
Solution Approach 1:
The patent divides the temperature detection function into multiple independent detection elements (first and second temperature detection elements) positioned at different locations on the heat roller. This segmentation ensures that if one element fails, the other can still provide temperature detection, thereby improving reliability without requiring a completely complex redundant system
Solution Approach 2:
The control circuit continuously monitors temperature through multiple detection elements and provides feedback to adjust the heating operation. When temperature exceeds predetermined thresholds, the system automatically adjusts heating power or shuts down, creating a closed-loop feedback mechanism that improves reliability through active monitoring and response
2Measurement precision
If multiple temperature detection elements are arranged on the heat roller, then the measurement precision of temperature is improved, but the device complexity increases due to additional connectors and control circuits
Solution Approach 1:
Different temperature detection elements are positioned at specific locations on the heat roller surface to detect temperatures at different zones. This local quality approach allows precise temperature monitoring at critical points without requiring comprehensive coverage, balancing measurement precision with system simplicity
Solution Approach 2:
The control circuit is designed to handle multiple temperature detection elements using a universal control logic that can process signals from different sensors and implement temperature control based on any or all detected values. This multi-functionality allows the same control circuit to manage various detection configurations without requiring separate dedicated circuits for each sensor
3Reliability
If temperature detection elements are frequently monitored for connection status, then the reliability of temperature control is improved, but the productivity of the image forming apparatus deteriorates due to additional safety checks
Solution Approach 1:
The control circuit performs connection status verification of temperature detection elements as a preliminary check before starting the image forming operation. By checking connections in advance and only performing additional safety monitoring when abnormalities are detected, the system ensures reliability without requiring continuous intensive monitoring that would reduce productivity
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 ensures accurate temperature control and improved safety by preventing abnormal heating, maintaining the temperature within a predetermined range, and providing a simple configuration for detecting connection issues or broken temperature detection elements.
Implementation Method 1
the temperature of the heat roller is detected by arranging a temperature detection element such as a thermistor
Implementation Method 2
a plurality of halogen lamp heaters being provided in the heat roller
Data Source
AI summary
An image forming apparatus with an image forming section which forms an toner image on a transported sheet; a fixing section which includes a heat source and fixes the toner image on the sheet; a coupling unit which electrically couples the image forming apparatus main unit and the fixing equipment to each other; and a circuit which detects the temperatures of various portions of the fixing equipment, controls the energization condition to the heat source depending on the temperature detection results and stops the energization of the heat source if a temperature beyond a predetermined temperature range is detected by either the first or second temperature detection element, if the coupling unit is disconnected, or if the second temperature detection element is broken.