Fuser Heater Power Control for Electrophotographic Imaging Devices
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Solution Overview
Problem
Electrophotographic printing devices face issues with fuser heater power variations due to AC line voltage fluctuations, leading to cracking, insufficient toner fusing, inaccurate prediction of fuser ready time, and temperature control difficulties, resulting in printing disruptions and media jams.
Innovation Solution
A method for heating the fuser heater using closed-loop feedback control, calculating and capping heater power based on current line voltage and temperature, and reducing power when excessive heating rates are detected to prevent cracking and ensure stable fusing temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the fuser heater is powered with high power to reach fusing temperature quickly, then the fuser ready time is reduced, but the heater member may crack due to excessive heating rate
Solution Approach 1:
The patent implements dynamic power adjustment by transitioning from open-loop high-power preheating to closed-loop feedback control. The system continuously monitors the heating rate and adjusts power delivery accordingly, allowing high power initially for rapid heating, then reducing power when the heating rate approaches a threshold to prevent cracking. This dynamic adaptation resolves the contradiction between speed and reliability.
Solution Approach 2:
The patent employs feedback control mechanisms where the controller monitors temperature and heating rate in real-time. When the heating rate exceeds a predetermined threshold during preheating, the system automatically reduces power to prevent heater cracking. This feedback loop enables the system to achieve fast heating while maintaining safety margins against thermal stress damage.
2Manufacturing precision
If the fuser heater power is increased to maintain fusing temperature, then toner fusing quality is improved, but heater cracking risk increases due to higher power variations
Solution Approach 1:
The patent uses closed-loop feedback control during the fusing operation phase. The controller continuously monitors the fuser heater temperature and adjusts power delivery to maintain the target temperature within a narrow tolerance band. This prevents both overheating (which causes cracking) and underheating (which causes poor fusing), thereby simultaneously achieving high fusing quality and heater reliability.
Solution Approach 2:
The patent implements parameter changes by adjusting power levels based on monitored temperature and heating rate. The system dynamically modifies electrical parameters (power, voltage) to maintain optimal thermal conditions, preventing thermal stress that leads to cracking while ensuring sufficient heat for quality fusing.
3Adaptability or versatility
If AC line voltage varies, then fuser heater power changes dramatically, but this makes temperature control difficult and leads to hot offset or media jams
Solution Approach 1:
The patent employs feedback control that continuously monitors fuser heater temperature and adjusts power delivery to compensate for line voltage variations. The controller compares actual temperature against target temperature and modifies heating power accordingly, maintaining stable fusing temperature despite fluctuations in AC line voltage, thereby preventing hot offset and media jams.
Solution Approach 2:
The system dynamically adapts to line voltage changes by continuously adjusting power delivery based on real-time temperature feedback. This dynamic response allows the fuser to maintain consistent operating temperature regardless of external voltage variations, ensuring reliable temperature control under varying electrical conditions.
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 prevents fuser heater cracking, maintains consistent fusing temperatures, and reduces disruptions by accurately predicting fuser ready time and ensuring efficient toner transfer, thereby improving printing reliability and quality.
Implementation Method 1
a fuser heater (208) of a fuser assembly (120) for an electrophotographic imaging device
Implementation Method 2
a thermistor which is secured to the fuser heater and the connection between the thermistor and the fuser heater
Data Source
AI summary
A system and methods for controlling the fuser heater of an electrophotographic imaging device, including initiating a preheating operation for preheating the fuser heater. Following a temperature of the fuser heater reaching a first predetermined temperature during the preheating operation, heater power is calculated based on a current temperature of the fuser heater and upon a second predetermined temperature. Current line voltage of a power supply line powering the electrophotographic device is also calculated, and a maximum heater power is determined based on the calculated current line voltage. The calculated heater power is then compared with the determined maximum heater power and the fuser heater is powered using the heater power equal to a lesser of the calculated heater power and the determined maximum heater power to heat the fuser heater from the first predetermined temperature to a second predetermined temperature.