Fixing Apparatus Heater Control for Harmonic Suppression
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Solution Overview
Problem
High-speed image forming apparatuses face challenges in suppressing harmonic current and flicker while increasing power to heaters, as existing power control methods are insufficient for further speed enhancements.
Innovation Solution
A fixing apparatus with two heating elements and switching elements, controlled by a controller that alternates between phase control and wave-number control waveforms to manage power distribution, ensuring electrical symmetry and reducing harmonic current and flicker.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If power supplied to heater is increased to achieve high speed printing, then processing speed is improved, but harmonic current and flicker occurrence increases
Solution Approach 1:
The patent divides the single heating element into two heating elements (first heating element and second heating element) with separate power supply paths. Each heating element is controlled by its own switching element, allowing independent power control. This segmentation enables the system to distribute power delivery across multiple elements, reducing harmonic current and flicker while maintaining high processing speed capability.
2Productivity
If power supplied to heater is increased to achieve high speed printing, then processing speed is improved, but device complexity increases
Solution Approach 1:
The patent combines phase control and wave-number control methods into a unified power control system that manages two heating elements. The controller integrates both control strategies and applies them alternately to the first and second heating elements within a control cycle, achieving high-speed printing with reduced harmonic current and flicker while managing system complexity through combined control approaches.
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
The solution effectively suppresses harmonic current and flicker, allowing for increased speed in image forming apparatuses while maintaining efficient power usage and thermal fixing of images on recording media.
Implementation Method 1
a first heating element, a second heating element... heat generated by the first heating element and the second heating element
Data Source
AI summary
A controller controls first and second switching elements so that, in both of the waveforms of alternating currents flowing through the first and second heating elements, a first period including both of a phase control waveform in which a current flows in a part of a half cycle of alternately current and a wave-number control waveform in which a current flows or does not flow over a half cycle of alternately current and a second period including only the wave-number control waveform alternately appear in a control cycle; when the first heating element operates in the first/second period, the second heating element operates in the second/first period; and both the waveforms of the alternating currents flowing through the first and second heating elements are electrically symmetric in the positive and negative directions during the control cycle.