Heating Device Priority Control for Voltage Variation
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Solution Overview
Problem
High-speed image forming apparatuses experience significant voltage variation and harmonic current issues due to simultaneous activation of multiple heaters, leading to discomfort, excessive power company condenser heating, and breaker errors, which existing control methods fail to adequately address.
Innovation Solution
A heating device with a controller that determines a fixed first priority order and a second priority order for multiple heat sources, ensuring that only the highest-ranked heat source is activated when multiple are needed, and adjusting the priority order based on recent activation to prevent simultaneous activation and maintain rank relationships.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If multiple heaters are activated simultaneously to rapidly raise temperature, then heating speed is improved, but voltage variation and harmonic current increase causing flickering and power infrastructure issues
Solution Approach 1:
The patent segments the heating operation by dividing multiple heaters into different priority groups and activating them sequentially rather than simultaneously. The controller activates heaters in a determined priority order, where higher-priority heaters are activated first and lower-priority heaters are activated only after higher-priority heaters are already operating, thereby preventing simultaneous activation and reducing voltage variation and harmonic current.
Solution Approach 2:
The patent implements periodic activation control where the controller determines priority orders at specific intervals (when heaters are activated or deactivated). This periodic reevaluation of priority orders ensures that heaters are activated in a controlled sequence rather than all at once, reducing the harmful electrical effects while maintaining heating effectiveness.
2Object-affected harmful factors
If phase controlling is used to gradually apply power to heaters, then voltage variation is reduced, but harmonic current is generated causing condenser heating and breaker errors
Solution Approach 1:
The patent extracts and eliminates the problematic phase controlling method entirely. Instead of using phase controlling that generates harmonic current, the invention uses a different approach: determining priority orders for heaters and activating them sequentially based on these priorities. This removes the source of harmonic current while still achieving the goal of reducing voltage variation through controlled activation sequencing.
3Object-affected harmful factors
If ON/OFF controlling with differentiated control cycles is used to prevent simultaneous OFF state, then some voltage variation is reduced, but heaters can still achieve activated state simultaneously causing strong harmonic current
Solution Approach 1:
The patent implements dynamic priority order determination where the controller continuously evaluates and updates the priority orders of heaters based on current operating conditions. This dynamic approach ensures that even when heaters have different control cycles, the system adaptively manages activation sequences to prevent simultaneous activation, thereby eliminating strong harmonic current while maintaining reduced voltage variation.
Solution Approach 2:
The system uses feedback mechanisms where the controller monitors the activated state of heaters and adjusts priority orders accordingly. When heaters are activated or deactivated, the controller reevaluates and updates priority orders to prevent future simultaneous activation events, creating a closed-loop control system that continuously prevents harmonic current generation.
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 reduces voltage variation and harmonic current, preventing discomfort and power infrastructure issues while ensuring even heater usage and extending their lifespan.
Implementation Method 1
plural heat sources configured to heat one or more members
Data Source
AI summary
The heating device includes plural heaters to heat fixing members; a power supplying device to supply power to the plural heaters; and a controller. The controller determines heater activation priority order for the heaters every control cycle, and allows the power supplying device to supply power to one of the heaters according to the heater activation priority order. When the controller judges that it is necessary to activate two or more of the heaters in a control cycle, the controller allows the power supplying device to supply power to one of the heaters having the highest rank in the heater activation priority order among the two or more of the heaters. The controller changes the heater activation priority order by according the lowest rank to the heater activated in the last control cycle while maintaining the rank relationship among the others of the heaters.