Power Source Circuit Zero Cross Detection and Standby Power Reduction
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Solution Overview
Problem
Existing power source circuits for image forming apparatuses face challenges in detecting power failures quickly and reducing standby power consumption, particularly due to the delay in discharging X capacitors and the increased circuit complexity.
Innovation Solution
The power source circuit employs a configuration where the Y capacitor discharging resistor also functions as the zero cross detection resistor, allowing for a simple circuit design that quickly detects power failures and reduces standby power consumption by selectively using the X capacitor discharging resistor based on the charging state, thereby minimizing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If an X capacitor discharging resistance is provided to quickly discharge the X capacitor upon power failure detection, then the power failure detection speed is improved, but the power consumption in the operation standby state increases
Solution Approach 1:
The patent applies dynamics by making the discharging resistance value changeable based on the operating state. Specifically, the resistance value is set to a first value (lower resistance) during operation to enable quick power failure detection, and changed to a second value (higher resistance) during standby state to reduce power consumption. This dynamic adjustment resolves the contradiction between fast detection and low standby power consumption.
Solution Approach 2:
The patent changes the resistance parameter of the X capacitor discharging resistance based on the charging state of the X capacitor. When the X capacitor is charged (during operation), the resistance is set to allow quick discharge for fast power failure detection. When the X capacitor is not charged (during standby), the resistance is increased to minimize power consumption. This parameter change strategy directly addresses the technical contradiction.
2Measurement precision
If the resistance of the X capacitor discharging resistor is reduced to improve power failure detection speed, then the detection accuracy is improved, but the power consumption increases
Solution Approach 1:
The patent makes the resistance value dynamic rather than fixed. During operation when power failure detection is critical, the resistance is set to a lower value for accurate and quick detection. During standby when detection is less critical, the resistance is set to a higher value to reduce energy loss. This dynamic approach resolves the contradiction between detection accuracy and energy loss.
Solution Approach 2:
The patent changes the resistance parameter based on the charging state of the X capacitor. When charged, the resistance is optimized for detection accuracy; when uncharged, the resistance is increased to reduce power consumption. This parameter adaptation resolves the contradiction between measurement precision and energy loss.
3Reliability
If a separate X capacitor discharging resistor and Y capacitor discharging resistor are provided, then the reliability of power failure detection is improved, but the device complexity increases
Solution Approach 1:
The patent makes the Y capacitor discharging resistor serve multiple functions: it discharges both the Y capacitor and the X capacitor. This multi-functionality maintains the reliability of power failure detection (by ensuring both capacitors are properly discharged) while reducing device complexity (by eliminating the need for a separate X capacitor discharging resistor). This directly resolves the contradiction between reliability and complexity.
Solution Approach 2:
The patent merges the function of discharging the X capacitor and the Y capacitor into a single resistor component. The Y capacitor discharging resistor is configured to handle both discharge functions, combining what would traditionally require separate components. This merging reduces circuit complexity while maintaining the reliability benefits of discharging both capacitors.
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 configuration enables rapid detection of power failures and reduces standby power consumption while maintaining accurate zero cross timing detection, achieving a balance between detection speed and power efficiency.
Implementation Method 1
a decrease in voltage of the power source circuit is delayed by the influence of electric charges charged in an X capacitor provided for inhibiting noises of the power source
Implementation Method 2
The resistance of a resistor discharging the X capacitor is reduced to allow the delay to be improved
Implementation Method 3
a ceramic heater coming into contact with the inner surface of the endless belt
Data Source
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AI summary
A power source includes rectifying means configured to rectify an alternating current (AC) voltage to be input, a first and second converter configured to convert the voltage rectified by the rectifying means, zero cross detection means configured to detect a zero cross of the AC voltage, voltage detection means configured to detect the AC voltage, a first capacitance element connected across a potential after being subjected to rectification by the rectifying means and a ground, a first discharging resistor configured to discharge electric charges charged in the first capacitance element and first switch means configured to cut off a current flowing to the first discharging resistor and stopping means configured, in a case where the AC voltage is detected by the voltage detection means and the detected voltage is smaller than a threshold value, to stop the operation of the second converter.