Parallel Resistance Heating Elements with Power Interrupter for Uniform Temperature Control
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Solution Overview
Problem
Existing fixing devices in electrophotographic image forming apparatuses face challenges in efficiently controlling the temperature of resistance heating elements, leading to potential overheating and uneven heating, which can affect the quality of the image forming process.
Innovation Solution
A heating device with multiple resistance heating elements connected in parallel, featuring a power control circuit, temperature detectors, and a power interrupter to maintain a predetermined temperature, ensuring safe operation and consistent heating by interrupting power supply when excessive temperature is detected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single resistance heating element is used for heating, then the device structure is simple, but the temperature distribution becomes uneven and overheating cannot be prevented
Solution Approach 1:
The single heating element is divided into multiple resistance heating elements (first, second, third, and fourth elements) arranged in parallel. Each element is equipped with its own temperature detector and can be independently controlled. This segmentation allows different regions to be heated according to their specific requirements, achieving uniform temperature distribution across the entire heating area while preventing localized overheating.
2Temperature
If multiple resistance heating elements are used for heating, then the temperature distribution becomes uniform, but the device structure becomes complex
Solution Approach 1:
Multiple resistance heating elements are arranged in parallel and connected to a common power supply system. The power interrupter is shared across all elements, and the control unit coordinates the operation of all temperature detectors and heating elements. This merging approach allows independent control of each element while maintaining a relatively compact and integrated device structure, reducing overall complexity compared to completely independent control systems.
Solution Approach 2:
The power interrupter serves multiple functions: it monitors temperature from different temperature detectors and can interrupt power to any or all heating elements based on temperature conditions. The control unit universally manages all heating elements and temperature detectors, providing a multi-functional control architecture that reduces the need for separate dedicated components for each heating element.
3Reliability
If temperature control is implemented for each heating element, then overheating is prevented, but the control system complexity increases
Solution Approach 1:
Each resistance heating element is equipped with a temperature detector that continuously monitors its own temperature and feeds this information back to the control unit. The control unit processes this feedback and activates the power interrupter when predetermined temperature conditions are met, creating a closed-loop feedback control system. This ensures reliable overheating prevention while using a standardized feedback mechanism that can be applied to multiple elements without proportionally increasing system complexity.
Solution Approach 2:
The power interrupter acts as an intermediary device between the temperature detectors and the power supply. It receives temperature information from multiple detectors and makes the decision to interrupt power based on predetermined conditions. This intermediary approach simplifies the control system architecture by centralizing the power interruption function rather than requiring complex control logic within each heating element circuit.
4Productivity
If power supply is continuously provided to heating elements, then heating efficiency is high, but overheating risk increases
Solution Approach 1:
The system provides power to the heating elements in a controlled, periodic manner rather than continuously. The power supply is activated when temperature conditions are acceptable and interrupted when predetermined temperature thresholds are reached. This periodic power supply pattern maintains high heating efficiency during active periods while preventing overheating through timely power interruption, achieving a balance between productivity and safety.
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
The solution effectively controls the temperature of the heating elements, preventing overheating and ensuring consistent heating performance, thereby improving the reliability and quality of the image forming process.
Implementation Method 1
a plurality of resistance heating elements arranged in a longitudinal direction of the base and electrically connected in parallel to each other
Implementation Method 2
a first temperature detector configured to detect a temperature of a first resistance heating element of the plurality of resistance heating elements; a second temperature detector configured to detect a temperature of a second resistance heating element
Data Source
AI summary
A heating device includes a base, resistance heating elements, a power control circuit, a first temperature detector, a second temperature detector, a power interrupter, and control circuitry. The resistance heating elements are arranged in a longitudinal direction of the base and electrically connected in parallel. The first detector detects a temperature of a first resistance heating element. The second detector detects a temperature of a second resistance heating element. The power interrupter interrupts power supplied to the resistance heating elements when the temperature of the second resistance heating element becomes a predetermined temperature or more. The control circuitry controls the circuit such that a temperature of each resistance heating element becomes a predetermined temperature, based on a result of detection of the first detector, and interrupts the power supplied to the resistance heating elements when the second detector detects predetermined temperature information regarding the second resistance heating element.