Power Factor Correction Control for Image Forming Apparatus
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Solution Overview
Problem
Existing image forming apparatuses face challenges in efficiently utilizing power factor improvement sections due to heat generation, efficiency reduction, and noise issues, particularly during printing operations, as these sections are often required only during startup and initial printing phases, and their switching is difficult to manage effectively due to varying load conditions.
Innovation Solution
An image forming apparatus with a power supply device that includes a rectification section, a power factor improvement section, a DC/DC converter, a current detection section, and a control section that controls the power factor improvement section based on detected current values to optimize its operation, using a bypassing switch to minimize switching losses and efficiently manage power factor correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the power factor improvement section is operated continuously during printing operations, then the power factor is maintained, but heat generation increases and efficiency decreases due to switching loss
Solution Approach 1:
The patent applies dynamics by making the power factor improvement section operable only during specific periods (startup and initial printing phases) rather than continuously. The control section dynamically adjusts the operation state based on the printing status, transitioning from operational state during startup to stopped state during steady-state printing, thereby reducing unnecessary switching losses while maintaining power factor where needed.
Solution Approach 2:
The patent implements periodic action by limiting the power factor improvement section operation to specific time periods: during startup and initial printing phases, but not during continuous printing operations. This periodic operation pattern reduces cumulative switching losses while maintaining power factor correction during the periods when it is most needed.
2Loss of energy
If the power factor improvement section is stopped during printing operations, then switching loss is reduced, but the power factor deteriorates which may cause current to exceed the 15A limit
Solution Approach 1:
The control section dynamically determines the operation state of the power factor improvement section based on real-time detection of printing status. During startup and initial printing phases when power factor correction is needed, the section is operated. During steady-state printing when the power factor is sufficient, the section is stopped, avoiding unnecessary switching losses while maintaining compliance with current limits.
3Reliability
If the power factor improvement section is always operated, then the current supplied from commercial power supply remains within 15A limit, but heat generation and noise increase
Solution Approach 1:
The system dynamically adjusts the operation state of the power factor improvement section based on printing status. During startup and initial printing phases, the section is operated to ensure current compliance with the 15A limit. During steady-state printing operations, the section is stopped, reducing heat generation and noise while maintaining current compliance through alternative control methods.
4Loss of energy
If the power factor improvement section is stopped during standby state, then efficiency improves, but the power factor cannot be maintained during critical startup and initial printing phases
Solution Approach 1:
The control section implements dynamic operation control based on printing status detection. During standby state, the power factor improvement section is stopped to minimize heat generation and improve efficiency. During startup and initial printing phases when power factor maintenance is critical, the section is activated to ensure proper current management, and then stopped during steady-state printing operations.
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 reduces switching losses and improves efficiency by selectively turning on/off the power factor improvement section based on current values, ensuring compliance with commercial power supply current standards while minimizing unnecessary operation during printing, thus enhancing overall performance and reducing heat generation.
Implementation Method 1
a rectification section (421) rectifying alternating current
Implementation Method 2
a power factor improvement section (422) improving a power factor of an input current
Implementation Method 3
a DC/DC converter (423) DC/DC converting current output from the power factor improvement section
Implementation Method 4
a heater (136) heating and fixing an unfixed image, formed on a recording material, to the recording material
Data Source
AI summary
The image forming apparatus includes a fixing section which has a heater and heats and fixes an unfixed image, formed on a recording material, to the recording material, a power supply section which has a rectification section rectifying alternating current, a power factor improvement section receiving input of current output from the rectification section, and a DC/DC converter DC/DC converting current output from the power factor improvement section, a current detection section which detects current flowing to the heater, and a control section which controls operation of the power factor improvement section according to current detected by the current detection section.