Fixing Device Dynamic Current Adjustment for Electrostatic Offset
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Solution Overview
Problem
Conventional fixing devices in image forming apparatuses face issues with electrostatic offset phenomena due to inconsistent toner charge levels, leading to toner adhesion on the fixing member and reduced device lifespan, as well as increased discharge over time causing insufficient charging for fixing processes.
Innovation Solution
A fixing device with an electric charge supplying device that adjusts the output current based on the toner charge amount, setting it to a higher value when the charge is low and a normal value when it's sufficient, to maintain optimal charging of the fixing member and prevent toner adhesion and electrostatic offset.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the fixing member is set with a large amount of electric charge to prevent electrostatic offset, then electrostatic offset phenomenon is restrained, but toner resin component adheres to the electric charge supplying device and device lifespan is reduced
Solution Approach 1:
The patent applies dynamics by transitioning from a static constant current charging method to a dynamic current adjustment method. The electric charge supplying device continuously monitors the charged amount of toner images and adjusts the output current accordingly - increasing current when toner charge is low and decreasing it when toner charge is sufficient. This dynamic adaptation prevents both electrostatic offset and toner resin adhesion to the charging device, resolving the contradiction between reliability and device lifespan.
Solution Approach 2:
The patent implements feedback control by measuring the charged amount of toner images and using this information to adjust the output current of the electric charge supplying device. The control unit receives detection results about toner charge levels and modifies the charging current in real-time. This feedback mechanism ensures the fixing member maintains appropriate charge levels without excessive charging that would cause toner resin adhesion, thereby extending device lifespan while preventing electrostatic offset.
2Reliability
If the output current of the electric charge supplying device is increased to ensure sufficient charging of the fixing member, then electrostatic offset is prevented, but toner resin component adheres to the electric charge supplying device
Solution Approach 1:
The patent applies dynamics by transitioning from a static constant current charging method to a dynamic current adjustment method. The electric charge supplying device continuously monitors the charged amount of toner images and adjusts the output current accordingly - increasing current when toner charge is low and decreasing it when toner charge is sufficient. This dynamic adaptation prevents both electrostatic offset and toner resin adhesion to the charging device, resolving the contradiction between reliability and device lifespan.
Solution Approach 2:
The patent applies parameter changes by dynamically adjusting the output current parameter of the electric charge supplying device based on detected toner charge levels. Instead of maintaining a fixed high current that causes toner resin adhesion, the system varies the current parameter within an appropriate range. When toner charge is sufficient, the current is reduced to prevent resin adhesion; when charge is low, the current is increased to prevent electrostatic offset, thus eliminating the harmful effects of excessive charging.
3Device complexity
If a constant current is supplied to the fixing member to maintain charge, then the structure is simple, but electrostatic offset occurs when toner charge amount varies
Solution Approach 1:
The patent implements feedback control by measuring the charged amount of toner images and using this information to adjust the output current of the electric charge supplying device. The control unit receives detection results about toner charge levels and modifies the charging current in real-time. This feedback mechanism ensures the fixing member maintains appropriate charge levels without excessive charging that would cause toner resin adhesion, thereby extending device lifespan while preventing electrostatic offset.
Solution Approach 2:
The patent applies self-service by enabling the electric charge supplying device to automatically adjust its output current based on detected toner charge levels without requiring external manual intervention. The system autonomously monitors the charging state of toner images and self-regulates the current output to maintain optimal fixing member charge levels. This self-adjusting capability prevents electrostatic offset while avoiding the complexity of manual control systems.
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
This solution ensures appropriate toner charging, reducing adhesion to the fixing member and the electric charge supplying device, while minimizing device deterioration and maintaining effective fixing performance.
Implementation Method 1
an electric charge supplying device electrically discharging electric charges with same polarity as polarity of toner composing the toner image and supply the electric charges to a surface of the fixing member
Implementation Method 2
The fixing member is rotatably provided, comes into contact with a recording medium on which a toner image is formed, and heats the recording medium
Implementation Method 3
The pressuring member is rotatably provided, and pressures the recording medium passing between the fixing member and the pressuring member
Data Source
AI summary
A fixing device includes a rotatable fixing member, a rotatable pressuring member and an electric charge supplying device. The fixing member contacts a recording medium having a toner image and heats the recording medium. The pressuring member pressures the recording medium between the fixing member and the pressuring member. The electric charge supplying device electrically discharges electric charges with same polarity as toner and supplies the electric charges to the fixing member. An output current value electrically discharged by the electric charge supplying device is adjusted on the basis of a toner charged amount of the toner image. When the toner charged amount is equal to or more than a threshold value, the output current value is set to a normal current value. When the toner charged amount is less than the threshold value, the output current value is set to a current value higher than the normal current value.