Switching mode power supply, apparatus and method of supplying power by using the same, and image forming apparatus therefor
First Claim
Patent Images
1. A switching mode power supply (SMPS) usable with an image forming apparatus to receive an alternating current (AC) power from an external electric power supply source and to output a direct current (DC) power, the SMPS comprising:
- a transformer to transform an electric power input to a primary coil and to output the transformed electric power to a secondary coil;
a switching device comprising a main switch connected to the primary coil to adjust the output electric power of the transformer and a switch controller connected to the main switch to control a switching operation of the main switch; and
a blocking device to block an electric power input to the switching controller when a supply state of an electric power to the image forming apparatus is a turned-off state,wherein, when the supply state of the electric power to the image forming apparatus is the turned-off state, the blocking device discharges a potential remaining on a passage from the secondary coil to the switching controller so that an output voltage of the SMPS is lowered below a reset voltage of the image forming apparatus to allow a rebooting of the image forming apparatus.
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Abstract
A switching mode power supply (SMPS) usable with an image forming apparatus receives an alternating current (AC) power from an external electric power supply source and outputs a direct current (DC) power. When a supply state of an electric power to the image forming apparatus is turned off, electric charges charged in a capacitor of the SMPS are discharged.
19 Citations
17 Claims
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1. A switching mode power supply (SMPS) usable with an image forming apparatus to receive an alternating current (AC) power from an external electric power supply source and to output a direct current (DC) power, the SMPS comprising:
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a transformer to transform an electric power input to a primary coil and to output the transformed electric power to a secondary coil; a switching device comprising a main switch connected to the primary coil to adjust the output electric power of the transformer and a switch controller connected to the main switch to control a switching operation of the main switch; and a blocking device to block an electric power input to the switching controller when a supply state of an electric power to the image forming apparatus is a turned-off state, wherein, when the supply state of the electric power to the image forming apparatus is the turned-off state, the blocking device discharges a potential remaining on a passage from the secondary coil to the switching controller so that an output voltage of the SMPS is lowered below a reset voltage of the image forming apparatus to allow a rebooting of the image forming apparatus. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method of supplying an electric power of a switching mode power supply (SMPS) in an image forming apparatus, the method comprising:
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transforming an electric power using a transformer of an SMPS; determining a supply state of the electric power to an image forming apparatus; and blocking an electric power input to a switching controller connected to a main switch to control the switching operation of the main switch that adjusts an output electric power of the transformer when the determined supply state of the electric power to the image forming apparatus is a turned-off state, wherein, when the determined supply state of the electric power to the image forming apparatus is the turned-off state, the blocking of the electric power input to the switching controller comprises discharging a potential remaining on a passage from an output of the transformer to the switching controller so that an output voltage of the SMPS is lowered below a reset voltage of the image forming apparatus to allow a rebooting of the image forming apparatus. - View Dependent Claims (8, 9, 10, 11)
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12. An image forming apparatus comprising:
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an image forming unit to perform an image on a printing medium; and a switching mode power supply (SMPS) to receive an alternating current (AC) power from an external electric power supply source and to output a direct current (DC) power to the image forming unit, wherein the SMPS comprises; a transformer to transform an electric power input to a primary coil and to output the transformed electric power to a secondary coil; a switching device comprising a main switch connected to the primary coil to adjust the output electric power of the transformer and a switch controller connected to the main switch to control a switching operation of the main switch; and a blocking device to block an electric power input to the switching controller when a supply state of an electric power to the image forming apparatus is a turned-off state, wherein, when the supply state of the electric power to the image forming apparatus is the turned-off state, the blocking device discharges a potential remaining on a passage from the secondary coil to the switching controller so that an output voltage of the SMPS is lowered below a reset voltage of the image forming apparatus to allow a rebooting of the image forming apparatus. - View Dependent Claims (13)
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14. A switching mode power supply (SMPS) usable with an image forming apparatus to receive an alternating current (AC) power from an external electric power supply source and to output a direct current (DC) power, the SMPS comprising:
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a transformer having a primary coil and a secondary coil to generate a driving voltage; a switching device configured to receive the driving voltage and to perform a switching operation on the primary coil according to the received driving voltage, the switching device comprising a switching controller; and a blocking device configured to block the driving voltage input to the switching controller of the switching device when a supply state of an electric power to the image forming apparatus is a turned-off state, wherein the blocking device discharges a potential remaining on a passage from the secondary coil to the switching controller until the driving voltage is lower than a reset voltage of the image forming apparatus to allow a rebooting of the image forming apparatus. - View Dependent Claims (15, 16, 17)
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Specification