Fuser Heater Relay Control for Pre-Power Line Fault Detection
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Solution Overview
Problem
Existing image forming apparatuses fail to detect malfunctions in the control line between the semiconductor switch and the control unit of the fuser device before powering on the fuser heater, leading to undetected issues such as disconnection or unconnection.
Innovation Solution
Incorporating semiconductor relay devices and heater relays between the fuser heater and the commercial power supply, with a controller that performs on/off control and line connection tests before powering on the fuser heater, detecting malfunctions by monitoring current thresholds and error signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the control line between the semiconductor switch and the control unit is disconnected or unconnected, then the malfunction is not detected before powering on the fuser heater, but the system continues to operate with potential safety risks
Solution Approach 1:
The patent implements preliminary detection of control line connection status before the fuser heater is powered on. The controller detects whether the control line between the semiconductor switch and control unit is properly connected prior to activation, allowing malfunction detection in advance and preventing unsafe operation without requiring complex additional hardware.
2Reliability
If voltage measurement is performed between the heater unit and the relay-semiconductor switch combination in power-on status, then malfunction detection is enabled, but detection of control line disconnection before power-on remains impossible
Solution Approach 1:
The patent shifts the detection timing to occur before the fuser heater is powered on. The controller performs control line connection status detection in the idle state prior to activation, enabling early malfunction detection and preventing the loss of time associated with post-power-on discovery of control line issues.
Solution Approach 2:
The patent introduces an intermediary detection mechanism that uses the existing control line itself as the test path. By applying a test signal through the control line before power-on and detecting the response, the system can verify connection status without requiring separate test hardware or waiting until power-on status.
3Device complexity
If the fuser heater is powered on with faulty control connections, then the system remains simple, but undetected malfunctions may cause safety issues or damage
Solution Approach 1:
The patent performs preliminary safety verification by detecting control line connection status before the fuser heater is powered on. This pre-activation detection prevents unsafe operation with faulty connections while maintaining system simplicity by using the existing control architecture without adding complex safety hardware.
Solution Approach 2:
The patent applies preliminary anti-action by preventing the fuser heater from operating when control line connection faults are detected. The controller inhibits power-on activation when malfunctions are identified, counteracting potential harmful effects before they can occur during heater operation.
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
Enables early detection of line connection issues in the control system, preventing the fuser heater from malfunctioning and ensuring reliable operation by avoiding power-on activation with faulty connections.
Implementation Method 1
the semiconductor relay device outputs an error signal if conducting current to the fuser heater is less than a predetermined threshold value in a period that the semiconductor relay device is controlled to be in a power conductive status
Implementation Method 2
a fuser device that fixes a toner image on a print sheet, and the fuser device includes a heater unit as a resistive heating element
Data Source
AI summary
An image forming apparatus includes a fuser heater, a semiconductor relay device between the fuser heater and a commercial power supply, a heater relay between the fuser heater and the commercial power supply, and a controller. The controller performs on/off control of the semiconductor relay device and the heater relay. The semiconductor relay device outputs an error signal if conducting current to the fuser heater is less than a threshold value in a period that the semiconductor relay device is controlled to be in a power conductive status. Further, the controller determines a line connection status between the controller and the semiconductor relay device correspondingly to whether the error signal is outputted from the semiconductor relay device or not in a period that the heater relay is controlled to be in a power cut-off status but the semiconductor: relay device is controlled to be in a power conductive status.