Constant Current High-Voltage Power Supply Leakage Detection

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Solution Overview

Problem

Constant current-type high-voltage power supply apparatuses experience abnormal noise and component damage due to unstable contact with loads, leading to potential device malfunction in applications like laser printers, where the output terminal physically contacts rotating rollers.

Innovation Solution

Incorporating a leakage current detection unit and a DC voltage output unit that detect and respond to leakage currents by adjusting power supply, using a PWM signal generation unit, power supply unit, and a power control unit to manage voltage and prevent damage by stopping power supply when leakage is detected.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the output terminal physically contacts rotating rollers to provide high-voltage, then power supply function is achieved, but unstable contact occurs causing abnormal noise and component damage

Engineering Contradiction:
Improvecontact stabilityVSAvoidabnormal noise and component damage
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent implements a feedback mechanism where the control unit continuously monitors the operational status of the power supply apparatus and receives signals indicating contact stability. When unstable contact or leakage current is detected, the control unit automatically stops power supply to the high-voltage circuit, preventing abnormal noise and component damage while maintaining reliable power delivery during normal operation.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent introduces a control unit as an intermediary between the power supply circuit and the load. This control unit acts as a mediator that monitors contact conditions and regulates power flow, stopping power supply when instability is detected thereby preventing harmful effects without compromising the primary power delivery function.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If continuous power supply is maintained to ensure operational continuity, then productivity is improved, but component damage risk increases when leakage occurs

Engineering Contradiction:
Improveoperational continuityVSAvoidcomponent safety
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The control unit continuously monitors operational parameters and leakage conditions, providing real-time feedback that enables automatic power supply interruption when leakage is detected, thus protecting components while maintaining operational continuity during normal conditions.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The control unit is configured to stop power supply in advance before leakage current can cause component damage. By detecting early signs of leakage and preemptively interrupting power flow, the system prevents damage while maintaining continuous operation during normal conditions.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3190778B1Image forming apparatus comprising constant current-type power supply apparatus
Publication Date: 2020.01.15 HEWLETT PACKARD DEVELOPMENT COMPANY LP
  • EP3190778B1 patent drawingFigure 1
  • EP3190778B1 patent drawingFigure 2
  • EP3190778B1 patent drawingFigure 3~4

AI summary

A constant current-type high-voltage power supply apparatus (100) which is used in an image forming apparatus includes a leakage current detection unit (140) that detects a leakage current leaked from at least one output terminal (170) of the constant current-type high-voltage power supply apparatus and outputs the detected leakage current, a direct current voltage output unit (150) that outputs different direct current (DC) voltages according to whether the leakage current detected by the leakage current detection unit is input, and a power control unit (160) that controls power output from and/or supplied to the constant current-type high-voltage power supply apparatus according to the output DC voltage.