POWER SOURCE UNIT AND IMAGE FORMING APPARATUS

• US 20110064445A1
• Filed: 08/10/2010
• Published: 03/17/2011
• Est. Priority Date: 02/23/2009
• Status: Active Grant

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited
• Inventors: YASHIRO, Akira
• Granted Patent: US 8,422,905 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: H02J 1/082 Plural DC voltage, e.g. DC supply voltage with at least two different DC voltage levels
• CPC Class Codes: H02J 9/005 using a power saving mode for copiers G03G15/5004

Abstract

A power source unit includes an AC/DC converter to convert alternating current to direct current output, an auxiliary power source storing electric power, a load detector to detect a high/low level of direct current output to a DC-using load device from the AC/DC converter, and a power supply controller. When load to be required exceeds alternating current power source limits, the power supply controller shuts down output of direct current from the AC/DC converter, and instead uses the auxiliary power source to supply power to the DC-using load device. When the load to be required is within alternating current power source limits, the power supply controller uses the AC/DC converter to supply power to the DC-using load device while the load detector detects high voltage for the DC-using load device, and the power supply controller uses the auxiliary power source to supply power to the DC-using load device and shuts down the AC/DC converter while the load detector detects low voltage for the DC-using load device.

Claims

1. A power source unit comprising:

an AC/DC (alternating current/direct current) converter to convert alternating current to direct current output;

an auxiliary power source capable of storing electric power;

a load detector to detect a high/low level of direct current output to a DC-using load device from the AC/DC converter; and

a power supply controller to control power supply according to a required load,

wherein, when load to be required exceeds alternating current power source limits, the power supply controller shuts down output of direct current from the AC/DC converter, and instead uses the auxiliary power source to supply power to the DC-using load device, and

wherein, when the load to be required is within alternating current power source limits, the power supply controller uses the AC/DC converter to supply power to the DC-using load device while the load detector detects high voltage for the DC-using load device, and

the power supply controller uses the auxiliary power source to supply power to the DC-using load device and shuts down the AC/DC converter while the load detector detects low voltage for the DC-using load device.

2. The power source unit of claim 1, wherein, when the load detector detects a high level for the direct current output and a power supply amount from the alternating current power source to an alternating current load device is low, the power supply controller causes the auxiliary power source to be charged when a remaining power amount of the auxiliary power source is low.

5. The power source unit of claim 2, wherein the auxiliary power source is charged by using the AC/DC converter.

6. The power source unit of claim 2, wherein, when the auxiliary power source supplies power to the DC-using load device within alternating current power source limits and the AC/DC converter is shut down, and a remaining power amount of the auxiliary power source is low, the power supply controller uses the AC/DC converter to supply power to the DC-using load device and to charge the auxiliary power source.

7. The power source unit of claim 2 wherein the auxiliary power source is charged by using alternating current from the alternating current power source.

8. The power source unit of claim 6, wherein, when the auxiliary power source supplies power to the DC-using load device within alternating current power limits and the AC/DC converter is shut down and a remaining power amount of the auxiliary power source is low, the power supply controller drives the AC/DC converter at a lower frequency to supply power to the DC-using load device and to charge the auxiliary power source using alternating current from the alternating current power source.

9. The power source unit of claim 2, wherein the auxiliary power source is charged using a private power source.

10. The power source unit of claim 2, wherein, when the auxiliary power source supplies power to the DC-using load device within alternating current power limits, and a remaining power amount of the auxiliary power source is low, the power supply controller continues to supply power to the DC-using load device from the auxiliary power source and charges the auxiliary power source using the AC/DC converter.

11. The power source unit of claim 10, wherein, when the auxiliary power source supplies power to the DC-using load device within alternating current power limits, the power supply controller computes a remaining time that the auxiliary power source can still supply power based on a remaining power amount of the auxiliary power source, and starts charging the auxiliary power source using the AC/DC converter before the remaining time becomes zero.

12. The power source unit of claim 11, further comprising a memory storing the remaining time of the auxiliary power source corresponding to the remaining power amount of the auxiliary power source,

wherein the remaining time is obtained by reading out a remaining time corresponding to the remaining power amount of the auxiliary power source being used for supplying power.

13. The power source unit of claim 5, wherein charging of the auxiliary power source by the AC/DC converter is stopped when a charge amount of the auxiliary power source reaches a predetermined value.

14. The power source unit of claim 5, wherein charging of the auxiliary power source using the AC/DC converter is conducted by operating the AC/DC converter at highest conversion efficiency.

15. The power source unit of claim 9, wherein the auxiliary power source is charged by a private power source when power of the private power source is available, and the auxiliary power source is charged by the AC/DC converter when power of the private power source is not available.

16. An image forming apparatus comprising:

an image forming unit to form an electrostatic latent image on a photoconductor, to develop the electrostatic latent image as a toner image, and to directly transfer the toner image to a sheet or indirectly transfer the toner image to a sheet using an intermediate transfer member;

a fusing unit having a fusing heater to fuse the toner image on the sheet;

a heater driver to control inputted alternating current and to supply the alternating current to the fusing heater; and

the power source unit of claim 1.

3. A power source unit comprising:

an AC/DC (alternating current/direct current) converter to convert alternating current to direct current output;

an auxiliary power source capable of storing electric power;

a power supply mode designation unit to designate one of an operation mode and an energy save mode, the operation mode designating supply of high direct current output to a DC-using load device from the AC/DC converter and the energy save mode designating supply of power to a specific smaller load DC-using load device; and

a power supply controller to control power supply according to a required load and a designated mode,

wherein, when the power supply mode designation unit designates the operation mode, and a load to be required exceeds alternating current power source limits, the power supply controller shuts downs output of direct current from the AC/DC converter, and instead uses the auxiliary power source to supply power to the DC-using load device,

wherein, when a load to be required is within alternating current power source limits,

the power supply controller uses the AC/DC converter to supply power to the DC-using load device while the operation mode is set, and uses the auxiliary power source to supply power to the DC-using load device and shuts down the AC/DC converter while the energy save mode is designated by the power supply mode designation unit.

4. The power source unit of claim 3, wherein, in the operation mode, when a power supply amount from the alternating current power source to an alternating current load device is low, the power supply controller causes the auxiliary power source to be charged when a remaining power amount of the auxiliary power source is low.