Cover Interlock Switch Power Control for Image Forming Apparatus
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Solution Overview
Problem
Current image forming apparatuses face challenges in safely controlling power supply according to the opening or closing of covers, which is crucial for user safety and compliance with international standards like UL, as they require precise management of high voltages to prevent current leakage.
Innovation Solution
The apparatus incorporates a dual power source system with interlock switches and a control unit that utilize transistors and MOSFETs to manage power supply based on the opening or closing of covers, ensuring safe operation by applying or interrupting power accordingly, thereby preventing accidental exposure to high voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a mechanical switch is used to interrupt power when cover is opened, then user safety is improved by preventing current leakage, but device complexity increases due to additional switching components
Solution Approach 1:
The patent extracts the power interruption function from a separate mechanical switch and integrates it into the existing interlock switch mechanism. The interlock switch simultaneously performs both the mechanical interlocking function and the power interruption function, eliminating the need for additional switching components while maintaining safety.
Solution Approach 2:
The patent merges the power supply control function with the interlock switch mechanism. The same interlock switch that detects cover opening/closing also controls the relay to interrupt or supply power, combining multiple functions into a single component system to reduce overall device complexity.
2Power
If high voltage is applied to photoconductor for toner attachment, then image forming capability is improved, but harmful factors increase due to current leakage risk to user
Solution Approach 1:
The patent applies preliminary anti-action by using the interlock switch to prevent power supply before the cover is closed. The system ensures that high voltage is only supplied to the photoconductor when the cover is properly closed, preemptively preventing any possibility of current leakage to the user while maintaining full power capability when safe.
3Productivity
If power is continuously supplied to maintain operational readiness, then productivity is improved, but safety risk increases due to potential exposure to high voltage
Solution Approach 1:
The patent implements dynamic power control where the power supply state changes based on cover position. Power is supplied only when the cover is closed (safe state) and interrupted when the cover is opened, creating a dynamic system that adapts to operational conditions to maintain readiness while ensuring safety.
Data Source
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AI summary
An image forming apparatus to safely supply or interrupt power according to opening or closing of a cover includes a power source unit to output low power and high power, an interlock switch unit to be turned on or off according to opening or closing of a cover, and an engine power circuit unit. The engine power circuit unit includes cover opening/closing sensing switches connected to the interlock switch unit to be turned on or off according to whether the interlock switch unit is on or off, and power supply switches connected to the power source unit to apply or interrupt the power from the power source unit according to a determination of whether the cover opening/closing sensing switches are on or off.