Fixing Apparatus Heater Power Control via Phase Angle Adjustment
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Solution Overview
Problem
The existing wave number control method in fixing apparatuses can cause flickering due to inrush current when the duty ratio of the drive power is low, leading to fluctuations in heater temperature.
Innovation Solution
A fixing apparatus with a power control unit that calculates and applies an AC voltage pattern based on temperature detection, selecting a half wave of the AC waveform and supplying power equivalent to a waveform with a predetermined phase angle on non-selected half waves to maintain consistent heating and prevent flickering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If wave number control is used to supply drive power to the heater, then the heater temperature can be controlled by adjusting the duty ratio, but when the duty ratio is low, the interval between half waves increases causing inrush current and flickering
Solution Approach 1:
The patent applies periodic action by using phase control to supply power at specific phase angles within each half wave of the AC waveform. This ensures continuous periodic heating action even when the duty ratio is low, preventing the temperature drops and inrush currents that cause flickering. The switching element is turned on at predetermined phase angles to maintain regular heating cycles.
Solution Approach 2:
The patent changes the parameter of phase angle to control power supply timing. By adjusting the phase angle at which the switching element is turned on within each half wave, the system can maintain stable heater temperature even at low duty ratios, preventing the interval-related issues that cause flickering while still achieving effective temperature control.
2Use of energy by stationary object
If the duty ratio of the application pattern is reduced to control heater temperature, then power consumption is reduced, but the interval between half waves increases causing inrush current generation
Solution Approach 1:
The patent changes the phase angle parameter to control when power is supplied within each half wave. This allows the system to reduce overall power consumption through low duty ratio while preventing inrush current by ensuring power is supplied at appropriate phase angles that maintain heater temperature, thus resolving the contradiction between energy efficiency and power stability.
Solution Approach 2:
The patent uses temperature detection feedback to determine the appropriate phase angle for power supply. The detection unit monitors heater temperature, and the control unit adjusts the phase angle accordingly to prevent inrush current while maintaining energy efficiency. This feedback mechanism ensures that power is supplied at optimal moments to avoid temperature fluctuations and inrush current.
3Reliability
If phase control is used to supply drive power by turning on switching element at certain phase angle, then fluctuation and flickering are suppressed, but the complexity of the control system increases
Solution Approach 1:
The patent uses phase angle as a controllable parameter to achieve flickering suppression. By adjusting the phase angle at which the switching element is turned on, the system can suppress flickering and temperature fluctuation without requiring complex additional hardware. The phase angle control provides a simple yet effective mechanism for maintaining stable heater operation.
Solution Approach 2:
The switching element serves multiple functions: it controls the duty ratio for overall power management and simultaneously controls the phase angle for flickering suppression. This multi-functionality reduces the need for separate control mechanisms, thereby limiting the increase in system complexity while achieving reliable flickering suppression.
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 effectively prevents flickering and maintains consistent heater temperature even at low duty ratios by controlling the phase angle of non-selected half waves, reducing inrush current and ensuring stable operation.
Implementation Method 1
a heater (611) configured to heat the fixing member (61a)
Implementation Method 2
a temperature detection unit (615) configured to detect a temperature of the heater (611)
Data Source
AI summary
A fixing apparatus configured to fix a coloring material attached to a recording medium by heating the recording medium by using a fixing member includes: a heater configured to heat the fixing member; an AC power source configured to apply AC voltage to the heater; a temperature detection unit configure to detect a temperature of the heater; and a power control unit configured to control drive power supplied to the heater from the AC power source by calculating an application pattern of AC voltage to be applied to the heater based on an output of the temperature detection unit, and by appropriately selecting a half wave of AC waveform from the AC power source based on the application pattern, wherein the power control unit supplies power equivalent to a waveform with a predetermined phase angle on a non-selected half wave from the AC power source to the heater.