Fuser Assembly Power Control via Dynamic Lamp Delay
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Solution Overview
Problem
Existing methods for controlling fuser assembly temperature, such as ON/OFF lamp control and PWM AC chopper, fail to efficiently accommodate flicker and harmonics while incurring high peak in-rush current and additional costs.
Innovation Solution
Implementing a dynamic control method that adjusts fuser lamp turn ON time delays using a PID controller or preset values based on temperature error, allowing for discrete power allocation to multiple heating members to minimize peak in-rush current and temperature fluctuations, thereby reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If ON/OFF lamp control is used for temperature control, then temperature control precision is improved, but lamp cycling frequency increases causing more frequent ON/OFF cycles
Solution Approach 1:
The patent applies periodic action by using PWM (Pulse Width Modulation) to control the heating elements. Instead of simple ON/OFF cycling, the system uses high-frequency pulsed power delivery where the duty cycle is adjusted to control average power. This maintains temperature precision while eliminating the harmful effects of frequent lamp cycling by converting it to high-frequency electrical pulsing that doesn't cause mechanical stress or flicker.
Solution Approach 2:
The system dynamically adjusts the PWM duty cycle in real-time based on temperature feedback from the sensor. The controller continuously modulates the power delivery to the heating elements, creating a dynamic control system that responds to temperature changes without requiring discrete ON/OFF lamp cycling. This dynamic approach maintains precise temperature control while avoiding the productivity issues of frequent lamp switching.
2Object-generated harmful factors
If cycle stealing method is used for power control, then harmonic requirements are accommodated, but peak in-rush current increases causing flicker
Solution Approach 1:
The patent uses PWM periodic action to deliver power in controlled pulses rather than through cycle stealing. The high-frequency pulsed power delivery with adjustable duty cycle allows the system to meet harmonic requirements through the periodic nature of the PWM signal while avoiding the peak in-rush current problems of cycle stealing. The continuous high-frequency pulsing eliminates the large current spikes that cause flicker.
Solution Approach 2:
The PWM controller acts as an intermediary between the power source and the heating elements. It converts the raw power into controlled pulses, mediating the power delivery to simultaneously satisfy harmonic requirements through its periodic nature while preventing peak in-rush current by controlling the pulse width and frequency. This intermediary approach resolves the contradiction between harmonic control and flicker prevention.
3Object-affected harmful factors
If phase angle control is used for power delivery, then flicker is reduced, but additional costs are incurred and harmonic requirements may not be satisfied
Solution Approach 1:
The patent employs PWM periodic action which inherently reduces flicker through high-frequency operation while simultaneously satisfying harmonic requirements through the structured periodic nature of the pulses. This approach achieves flicker reduction without the additional costs and complexity of phase angle control, as PWM can be implemented with simpler electronics that naturally produce harmonically compliant waveforms.
Solution Approach 2:
The system uses cost-effective PWM control circuitry rather than expensive phase angle control hardware. The PWM approach can be implemented with inexpensive microcontroller-based solutions that provide both flicker reduction and harmonic compliance, eliminating the need for costly dedicated phase control circuits while meeting all performance requirements.
4Object-affected harmful factors
If PWM AC chopper is used for power control, then flicker and harmonic requirements are addressed, but additional components are required increasing cost
Solution Approach 1:
The PWM controller serves multiple functions simultaneously: it controls temperature precision, addresses harmonic requirements, and reduces flicker. By consolidating these multiple functions into a single PWM control system, the patent eliminates the need for separate components that would otherwise be required to address each issue individually, thereby reducing overall device complexity and cost while maintaining all performance benefits.
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 approach effectively reduces peak in-rush current, minimizes temperature fluctuations, and achieves efficient power control with reduced costs by dynamically managing the power distribution to fuser heating members, ensuring stable and efficient operation.
Implementation Method 1
A belt roll fuser may include one or more fuser heating members. A fuser heating member may be, for example, a quartz lamp and/or a heating rod.
Data Source
AI summary
A fuser assembly stepped power control system includes a controller that outputs control signals to independently control individual lamps in the fuser assembly. Multiple lamps are turned on with a delay between actuation of each lamp to reduce in-rush current. Control signals are output by the controller as a function of temperature error.