Fixing Device Surge Protection via High-Resistance Conductor
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Solution Overview
Problem
Existing fixing devices in image forming apparatuses are vulnerable to damage from surge currents, which can damage the insulation layer of the heater, leading to performance issues with static charge elimination.
Innovation Solution
A fixing device is designed with a conductor and a resistor, where the conductor has a resistance value greater than 100 kΩ and is in contact with the conductive layer of the rotator, and the resistor is grounded via the image forming apparatus, effectively diverting excessive currents to prevent insulation layer damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a static charge eliminator made of metal hair is used with a resistor having a resistance of about several MΩ, then static charge elimination performance is improved, but the resistor may be damaged by surge current, reducing reliability
Solution Approach 1:
The patent introduces a conductor as an intermediary component between the static charge eliminator and ground. This conductor has a controlled resistance value greater than 100 kΩ, which serves as a mediator to safely divert surge currents away from the insulation layer while maintaining the static charge elimination function. The conductor acts as a protective intermediary that prevents direct exposure of the insulation layer to harmful surge currents.
2Reliability
If the conductor resistance is increased to improve surge current protection, then insulation layer protection is improved, but static charge elimination performance may deteriorate
Solution Approach 1:
The patent optimizes the resistance parameter of the conductor to be greater than 100 kΩ. This specific parameter range is carefully selected to balance two opposing requirements: high enough resistance to effectively divert surge currents and protect the insulation layer, but low enough to maintain adequate static charge elimination performance. By precisely controlling this parameter, the system achieves both protection and functionality.
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 proposed configuration significantly enhances the reliability of the fixing device by preventing damage to the insulation layer from surge currents, ensuring consistent performance and extending the device's lifespan.
Implementation Method 1
The conductor has a resistance value larger than 100 kΩ. The resistor has one end electrically coupled in series to the conductor and another end grounded via an image forming apparatus.
Implementation Method 2
A current flowing through the heater causes the resistive heat generator to generate heat.
Implementation Method 3
The heater includes a resistive heat generator. A current flowing through the heater causes the resistive heat generator to generate heat. The heat heats the fixing belt.
Data Source
AI summary
A fixing device includes a rotator, a pressure rotator, a heater, a conductor, and a resistor. The rotator includes a conductive layer. The pressure rotator presses the rotator to form a fixing nip between the rotator and the pressure rotator. The heater is in contact with an inner surface of the rotator to heat the rotator. The conductor is in contact with the conductive layer of the rotator and has a resistance value larger than 100 kΩ. The resistor has one end electrically coupled in series to the conductor and another end grounded via an image forming apparatus.