Power supply device and method for image forming apparatus

• US 20100166449A1
• Filed: 03/05/2010
• Published: 07/01/2010
• Est. Priority Date: 09/03/2009
• Status: Active Grant

• Current Assignee: HP Printing Korea Co., Ltd. (HP Inc.)
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Hong, Hyung-Won
• Granted Patent: US 8,593,837 B2
• Time in Patent Office: Days
• US Class Current: 399/88
• CPC Class Codes: G03G 15/5004 Power supply control, e.g. power-saving mode, automatic power turn-off
• CPC Class Codes: G03G 15/80 Details relating to power supplies, circuits boards, electrical connections
• CPC Class Codes: H02M 1/322 Means for rapidly discharging a capacitor of the converter for protecting electrical components or for preventing electrical shock
• CPC Class Codes: H02M 1/44 Circuits or arrangements for compensating for electromagnetic interference in converters or inverters
• CPC Class Codes: H02M 3/33507 with automatic control of the output voltage or current, e.g. flyback converters H02M3/33561, H02M3/33569 take precedence

Abstract

Provided is a power supply device for an image forming apparatus, the power supply device including: a filter unit filtering alternating current (AC) power from an AC power source; and a converter generating a direct current (DC) power from the filtered AC power, wherein the filter unit includes: a capacitor connected to the AC power source; a discharge device connected to the capacitor and discharging electric charges accumulated in the capacitor; and a switching device switching connection between the capacitor and the discharge device according to a power supply mode of the power supply device.

Claims

1. A power supply device for an image forming apparatus, the power supply device comprising:

an alternating current (AC) power source;

a filter unit filtering alternating current AC power from the AC power source; and

a converter generating direct current (DC) power from the filtered AC power, wherein the filter unit comprises;

a capacitor connected to the AC power source;

a discharge device connected to the capacitor and discharging electric charges accumulated in the capacitor; and

a switching device switching connection between the capacitor and the discharge device according to a power supply mode of the power supply device.

2. The power supply device of claim 1, wherein the power supply mode comprises an on-mode, which is a state where the AC power is supplied, or an off-mode, which is a state where the AC power is not supplied, and the switching device disconnects the capacitor from the discharge device when the power supply mode is the on-mode and connects the capacitor and the discharge device when the power supply mode is the off-mode.

3. The power supply device of claim 2, wherein the switching device is a normally closed contact relay which is turned-off when the AC power is supplied and turned-on when the AC power is not supplied.

4. The power supply device of claim 1, wherein the power supply mode comprises a standby mode or a normal operation mode, which are states where the AC power is supplied, or an off-mode, which is a state where the AC power is not supplied, and the switching device receives a control signal corresponding to the power supply mode from an external circuit connected to the power supply device and switches connection between the capacitor and the discharge device according to the received control signal.

5. The power supply device of claim 4, wherein the control signal comprises a first logic level signal or a second logic level signal, and the first logic level signal is a signal corresponding to the standby mode or the normal operation-mode, and the second logic level signal is a signal corresponding to the off-mode.

6. The power supply device of claim 5, wherein the switching device disconnects the capacitor from the discharge device when the received control signal is the first logic level signal, and connects the capacitor and the discharge device when the received control signal is the second logic level signal or when the control signal is not received.

7. The power supply device of claim 1, further comprising a voltage detecting unit detecting the DC power, which is output from the converter, and sending a control signal to the switching device, wherein the power supply mode comprises an on-mode which is a state where the DC power, which is output from the voltage detecting unit, is detected, or an off-mode which is a state where the DC power is not detected, and the switching device receives the control signal corresponding to the power supply mode and switches connection between the capacitor and the discharge device according to the received control signal.

8. The power supply device of claim 7, wherein the control signal comprises a first logic level signal corresponding to the on-mode or a second logic level signal corresponding to the off-mode, and the switching device disconnects the capacitor from the discharge device when the received control signal is the first logic level signal and connects the capacitor and the discharge device when the received control signal is the second logic level signal or when the control signal is not received.

9. The power supply device of claim 4, wherein the switching device performs a switching operation according to the control signal, and comprises a normally closed contact relay which is turned-off when the control signal is a first logic level signal and turned-on when the control signal is a second logic level signal or when the control signal is not received.

10. The power supply device of claim 7, wherein the switching device performs a switching operation according to the control signal, and comprises a normally closed contact relay which is turned off when the control signal is a first logic level signal and turned-on when the control signal is a second logic level signal or when the control signal is not received.

11. The power supply device of claim 1, wherein the filter unit is an electromagnetic interference (EMI) filter removing EMI of the AC power.

12. The power supply device of claim 1, wherein the power supply device is a switching mode power supply (SMPS) device.

23. The power supply device of claim 1, wherein the switching device is connected in series to one end of the discharge device.

24. The power supply device of claim 1, further comprising a plurality of the discharge devices, the switching device being connected in series between the discharge devices.

25. The power supply device of claim 1, wherein the discharge device is a resistor.

13. A power supply method for an image forming apparatus, the method comprising:

determining a power supply mode of a power supply device for an image forming apparatus; and

switching connection between a capacitor and a discharge device, the capacitor being connected to an alternating current (AC) power source according to the determined power supply mode and the discharge device discharging electric charges accumulated in the capacitor.

14. The method of claim 13, wherein the power supply mode comprises an on-mode, which is a state where the AC power is supplied, or an off-mode, which is a state where the AC power is not supplied, and the switching the connection between the capacitor and the discharge device comprises disconnecting the capacitor from the discharge device when the power supply mode is the on-mode, and connecting the capacitor and the discharge device when the power supply mode is the off-mode.

15. The method of claim 13, wherein the power supply mode comprises a standby mode or a normal operation mode, which are states where the AC power is supplied, or an off-mode, which is a state where the AC power is not supplied and the determining of the power supply mode comprises:

determining whether a control signal corresponding to the power supply mode is received from an external circuit connected to the power supply device, and

wherein the switching of the connection between the capacitor and the discharge device comprises disconnecting the capacitor from the discharge device when the determined control signal is a first logic level signal corresponding to the standby mode or the normal operation mode, and connecting the capacitor and the discharge device when the determined control signal is a second logic level signal corresponding to the off-mode, or determined that the control signal is not received.

16. The method of claim 13, further comprising detecting DC power which is output from the image forming apparatus, wherein the power supply mode comprises an on-mode, which is a state where the output DC power is detected, or an off-mode, which is a state where the output DC power is not detected;

and the determining of the power supply mode comprises determining whether a control signal corresponding to the power supply mode is received,

wherein the switching of the connection between the capacitor and the discharge device comprises disconnecting the capacitor from the discharge device when the determined control signal is a first logic level signal corresponding to the on-mode, and connecting the capacitor and the discharge device when the determined control signal is a second logic level signal corresponding to the off-mode or when determined that the control signal is not received.

17. A power supply device comprising:

a first power source;

a filter unit filtering a first power supplied from the first power source; and

a converter generating a second power from the filtered first power, wherein the filter unit comprises;

a capacitor connected to the first power source;

a discharge device connected to the capacitor and discharging electric charges accumulated in the capacitor; and

a switching device switching connection between the capacitor and the discharge device according to a power supply mode of the power supply device,

wherein the power supply device outputs the generated second power.

18. The power supply device of claim 17, wherein the power supply mode comprises an on-mode, which is a state where the first power source is supplied, or an off-mode, which is a state where the first power is not supplied, and the switching device disconnects the capacitor from the discharge device when the power supply mode is the on-mode and connects the capacitor and the discharge device when the power supply mode is the off-mode.

19. The power supply device of claim 17, wherein the power supply mode comprises a standby mode or a normal operation mode, which are states where the first power is supplied, or an off-mode, which is a state where the first power is not supplied.

20. The power supply device of claim 17, further comprising a voltage detecting unit detecting a second power, output from the converter, and sending a control signal to the switching device,

wherein the power supply mode comprises an on-mode, which is a state where the second power, output from the voltage detecting unit, is detected, or an off-mode, which is a state where the second power is not detected, and the switching device receives the control signal corresponding to the power supply mode and switches connection between the capacitor and the discharge device according to the received control signal.

21. The power supply device of claim 18, wherein the switching device receives a control signal, and disconnects the capacitor from the discharge device when the received control signal is a first logic level signal, and connects the capacitor and the discharge device when the received control signal is a second logic level signal or when the control signal is not received.

22. The power supply device of claim 19, wherein the switching device receives a control signal, and disconnects the capacitor from the discharge device when the received control signal is a first logic level signal, and connects the capacitor and the discharge device when the received control signal is a second logic level or when the control signal is not received.