Power Supply Inrush Current Control for Image Forming Apparatus
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Solution Overview
Problem
Image forming apparatuses experience significant inrush currents due to sudden voltage fluctuations when transitioning from a power saving mode to an activation mode or from a turned-off state to a turned-on state, which destabilizes the system and stresses circuit components.
Innovation Solution
The apparatus includes a power supply that converts AC voltage to DC voltage, with a controller managing the output by initially providing a first DC voltage to turn on the image forming unit and subsequently switching to a higher second DC voltage after the unit is activated, stabilizing the system by reducing inrush current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the image forming apparatus transitions from power saving mode to activation mode, then the apparatus becomes operational and ready for use, but a large inrush current occurs due to sudden voltage fluctuation
Solution Approach 1:
The controller activates the image forming unit at a reduced voltage level before full operation is required. This preliminary action allows the unit to be ready for operation while avoiding the sudden voltage fluctuation that causes inrush current, thus resolving the contradiction between operational readiness and harmful current spikes.
2Reliability
If the apparatus is turned on from a turned-off state, then the image forming unit becomes active, but system stability decreases due to stress on circuit components from inrush current
Solution Approach 1:
The controller applies a reduced voltage to the image forming unit before full power activation. This preliminary action reduces the inrush current and associated stress on circuit components, thereby maintaining system stability while still enabling the unit to become active and operational.
3Speed
If full voltage is supplied immediately to the image forming unit, then the unit activates quickly, but the output voltage of the SMPS drops due to inrush current
Solution Approach 1:
The controller supplies reduced voltage to the image forming unit as a preliminary step before full voltage activation. This approach enables the unit to begin activating without causing significant inrush current, thereby maintaining SMPS output voltage stability while still achieving relatively quick activation.
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 approach effectively minimizes inrush current and stabilizes the power supply system, reducing stress on circuit components and ensuring stable output voltage.
Implementation Method 1
a power supply 110 configured to receive and convert an alternating current (AC) voltage into at least one direct current (DC) voltage
Data Source
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AI summary
An image forming apparatus (100) includes an image forming unit (130), a power supply (110) configured to receive and convert an alternating current (AC) voltage into at least one direct current (DC) voltage, and output the same, a DC-DC converter (120) configured to convert the at least one DC voltage into a driving voltage at a predetermined level, and a controller (140) configured to be activated by the driving voltage, and control the power supply to turn on the image forming unit by supplying a first DC voltage to the image forming unit, and after the image forming unit has been turned on, supplying a second DC voltage at a higher level than a level of the first DC voltage to the image forming unit.