Resistive Heat Generator Power Control for Image Fixing
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Solution Overview
Problem
Existing image forming apparatuses with resistive heat generators face challenges in controlling power due to variations in resistance values caused by inconsistencies in the heat generating pattern, leading to inconsistent temperature control and potential failures in fixing images on recording media.
Innovation Solution
Incorporating a power controller that detects the temperature-resistance property of the resistive heat generator before use and adjusts the power duty cycle based on this property, ensuring consistent power supply and temperature control, even with variations in resistance values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If screen printing is used to produce the resistive heat generator, then manufacturing ease is improved, but manufacturing precision deteriorates due to variation in line width and thickness
Solution Approach 1:
The patent applies preliminary action by measuring the resistance value of the heat generating pattern before it is mounted on the fixing belt, and storing this measurement data. This allows the system to compensate for manufacturing variations later during operation, rather than requiring perfect manufacturing precision upfront.
Solution Approach 2:
The patent changes the operational parameters by adjusting the power supply duty cycle based on the measured resistance value. The control unit calculates an appropriate duty cycle that compensates for resistance variations, thereby maintaining consistent heating performance despite manufacturing precision issues.
2Ease of repair
If the resistive heat generator is removably installed, then ease of repair is improved, but reliability deteriorates due to substantial variation in total resistance value
Solution Approach 1:
The system performs preliminary measurement of the resistance value when the heat generating pattern is first installed or replaced. This measurement data is stored and used for subsequent control adjustments, ensuring reliable operation even with removable components that may have varying resistance values.
Solution Approach 2:
The patent implements feedback control by continuously monitoring the resistance value and adjusting the power supply duty cycle accordingly. The control unit uses the measured resistance data to calculate the appropriate duty cycle, creating a closed-loop system that maintains reliability despite component removal and reinstallation.
3Productivity
If power is supplied continuously to the resistive heat generator, then productivity is improved, but temperature control stability deteriorates due to resistance variations
Solution Approach 1:
The patent applies periodic action by using pulse width modulation (duty cycle control) instead of continuous power supply. The power is supplied in periodic pulses with adjusted width based on the measured resistance value, which maintains productivity while improving temperature control stability through the calculated duty cycle.
Solution Approach 2:
The system changes the power supply parameter from continuous to variable duty cycle based on measured resistance. The control unit calculates the appropriate duty cycle percentage that compensates for resistance variations, allowing continuous operation with stable temperature control.
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 enables stable and consistent image fixing by accurately controlling the power supplied to the resistive heat generator, reducing the risk of image failure and improving overall printing quality.
Implementation Method 1
the heater heats the fixing belt. The base of the heater extends in an axial direction of the fixing belt. the resistive heat generator is disposed on the base
Data Source
AI summary
An image forming apparatus includes a resistive heat generator, a temperature detector, and a power controller that detects a temperature-resistance property of the resistive heat generator before the resistive heat generator is used when the resistive heat generator is removably installed. The power controller obtains power supplied to the resistive heat generator and a change in a temperature of the resistive heat generator, that is detected by the temperature detector, while the power controller supplies the power at a predetermined power duty cycle for adjustment to the resistive heat generator. The power controller calculates the temperature-resistance property of the resistive heat generator based on the power and the change in the temperature that are obtained. The power controller adjusts a power duty cycle at which the power is supplied to the resistive heat generator in use of the resistive heat generator, based on the temperature-resistance property.