Fixing Device Malfunction Preventing Circuit for Power Stability
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Solution Overview
Problem
In digital multifunction peripherals, the safety circuit of the fixing device malfunctions due to unstable power supply voltage, affecting temperature detection and voltage reference stability, leading to potential overheating and system failures.
Innovation Solution
A malfunction preventing circuit is introduced to stop the operation of the safety circuit when the power supply voltage is unstable, ensuring stable operation by invalidating the safety circuit's actions until all power supply systems stabilize, and a dual-power system configuration is used to maintain accurate temperature detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the safety circuit operates with unstable power supply voltage, then the temperature detection and reference voltage become unstable, but the device complexity increases to prevent malfunctions
Solution Approach 1:
The malfunction preventing circuit detects power supply voltage stability in advance before the safety circuit performs temperature detection. When voltage instability is detected, the malfunction preventing circuit invalidates the safety circuit output beforehand, preventing false temperature alarm malfunctions before they occur
Solution Approach 2:
The malfunction preventing circuit acts as an intermediary between the power supply system and the safety circuit. It monitors power supply voltage stability and controls the validity of the safety circuit output, thereby protecting the temperature detection function from power supply fluctuations without requiring direct modification of the safety circuit
2Measurement precision
If the thermopile output is compared with reference voltage during power supply transitions, then temperature detection may occur, but false alarms are caused due to voltage instability
Solution Approach 1:
The malfunction preventing circuit applies preliminary anti-action by detecting power supply voltage instability and invalidating the safety circuit output before false temperature alarms can be generated. This counteracts the harmful effect of voltage-induced false readings before they affect system operation
Solution Approach 2:
The malfunction preventing circuit continuously monitors power supply voltage and provides feedback control to the safety circuit validity signal. When voltage instability is detected, the feedback mechanism automatically invalidates the safety circuit output, creating a closed-loop protection system that adapts to power supply conditions
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
Prevents safety circuit malfunctions and ensures the fixing device's safe operation by stabilizing power supply systems, preventing false temperature readings and ensuring the system's safety during power fluctuations.
Implementation Method 1
The safety circuit monitors the temperature in the fixing device using a thermistor or a thermopile
Implementation Method 2
a heat source that converts electric power into heat
Data Source
AI summary
A fixing device fixes a toner image on a recording medium. The fixing device includes a heat source that converts electric power into heat and a fixing member that gives the heat generated by the heat source to the recording medium on which the toner image is formed. The fixing device includes a safety circuit that forcibly interrupts voltage supplied from a power supply to the heat source if the temperature in the device detected by a temperature detection sensor exceeds reference temperature. The fixing device has a malfunction preventing circuit that stops the operation of the safety circuit in order to prevent the voltage supplied to the heat source from being forcibly interrupted when the voltage of the power supply supplied to the heat source is unstable.