JP2007006588A - Power unit and fault determining method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power unit which is high in power saving efficiency and is easy of determining fault. <P>SOLUTION: This power unit shifts to a power saving mode and stops the power supply partially, when a power saving signal inputted from a controller 20 is at low level, and resumes the power supply to a load, when the power saving signal gets at high level. It has switches 11 and 12 which enforcedly switch the power saving signals to high level. In the case of a power unit which starts up to supply power when the power saving signal inputted from the controller 20 is to high level, the power unit will not start up, unless high level signal is inputted, so it cannot decide the fault. Thus, by providing it with switches 11 and 12 and putting power saving signal enforcedly at high level it can decide whether it is the fault on the side of the controller 20 or the fault of the power source 10. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a power supply device having a power saving function. In particular, the present invention relates to a failure determination technique for the power supply device.

  Recent image forming apparatuses are equipped with a power saving function as a standard, and have become a power supply system that cuts off power supply to unnecessary parts during standby. For this reason, the power supply apparatus is configured to stop unnecessary power supplies during standby according to a control signal from the control apparatus.

  However, when the power control mode is set to turn off when the control signal is at a high level, the control signal is set to a high level when the power consumption in the power saving mode is less than 1 W. Power consumption is also a problem.

  In view of this, a technique has been proposed in which the level of a control signal to be shifted to the power saving mode is changed to a low level to suppress power consumption.

  Patent Document 1 discloses a technique for accurately distinguishing between the normal state and the short-circuit state even when the currents flowing through the power supply line are close to each other.

  Patent Document 2 discloses a technique in which, in the drive sequence of the drive unit, an overcurrent detection threshold is set according to the drive phase, and the output voltage cutoff value can be variably set.

JP-A-5-328596 Japanese Patent Laid-Open No. 9-12177

  However, since the power supply does not start up unless a high-level signal, for example, 5 V, is input to the power supply, there is a failure on the power supply side, or the control unit side that controls this other than the power supply side including a failure such as a harness short circuit. There is a problem that it is difficult to understand whether this is a malfunction. Along with this, problems such as misdiagnosis, erroneous replacement and longer repair time occur. In addition, Patent Documents 1 and 2 do not pay attention to such problems, and there is no disclosure of techniques to solve them.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a power supply apparatus that has high power saving efficiency and can easily determine a failure.

  In order to achieve this object, the power supply device of the present invention shifts to the power saving mode when the control signal input from the external device is at a low level, partially stops the power supply, and the control signal is at a high level. Then, the power supply device resumes the power supply to the load, and has a switching means for forcibly switching the control signal to a high level. In the case of a power supply device that rises when a control signal input from an external device is at a high level and supplies power, the power supply device does not start up unless a high-level signal is input, and a failure cannot be determined. Therefore, by providing a switching means and forcing the control signal to the high level, it is possible to determine whether the failure is on the external device side or the power supply device. In addition, since the control signal shifts to the power saving mode by setting the control signal to a low level, the power consumption in the entire power saving mode including the external device can be reduced.

  In the power supply device configured as described above, the power supply device includes a first power supply unit that supplies power to the load even in the power saving mode, and a second power supply unit that switches on and off by the control signal, The switching means may forcibly switch the control signal to a high level by the power from the first power supply unit, and restart the power supply by the second power supply unit. Therefore, the second power supply unit can be restarted inside without receiving external power supply.

  In the power supply device having the above-described configuration, the switching unit may be a switch that switches on and off a signal line that connects the power line of the first power supply unit and the signal line of the control signal. Therefore, the second power supply unit can be restarted with a simple configuration.

  In the power supply device configured as described above, the switching means is means for connecting the power supply line of the first power supply unit and the signal line of the control signal when a connector connecting the power supply apparatus and the load is disconnected. There should be. Therefore, when the power supply device is disconnected from the load, the power supply is automatically turned on to the second power supply unit, so that it can be determined whether or not the power supply unit has failed.

  In the power supply device having the above-described configuration, when the connector that connects the power supply device and the load is disconnected, the switching unit forcibly turns on the relay of the interlock circuit and the output of the power supply device is a terminal for confirming the output. It is good to output to. Therefore, even if a device that automatically turns off the power supply when a connector such as an interlock circuit is disconnected is installed, the relay can be forcibly turned on to check the output of the power supply device.

  In the power supply device having the above-described configuration, it is preferable that the second power supply unit includes a display unit that displays whether the power supply is possible. Therefore, it can be visually determined whether the second power supply unit is in a state in which power can be supplied.

  In the failure determination method of the present invention, when the control signal input from the external device is at a low level, a step of shifting to a power saving mode and partially stopping the supply of power, and when the control signal is at a high level, Resuming the power supply to the power supply, and forcibly switching the control signal to a high level to determine a failure of the power supply device. In the case of a power supply device that rises when a control signal input from an external device is at a high level and supplies power, the power supply device does not start up unless a high-level signal is input, and a failure cannot be determined. Therefore, by providing a switching means and forcing the control signal to the high level, it is possible to determine whether the failure is on the external device side or the power supply device. In addition, since the control signal shifts to the power saving mode by setting the control signal to a low level, the power consumption in the entire power saving mode including the external device can be reduced.

  The present invention can provide a power supply device having high power saving efficiency and high safety and maintainability.

  Preferred embodiments of the present invention will be described with reference to the accompanying drawings.

  First, the configuration of the present embodiment will be described with reference to FIG. FIG. 1 shows the configuration of an image forming apparatus 1 equipped with a power supply device. The image forming apparatus 1 according to the present exemplary embodiment includes a power supply unit 10 that supplies power to a load, a control unit 20 that controls the power supply unit 10 and the image forming unit 21, and image formation according to the control of the control unit 20. And an image forming unit 21 that performs the operation.

  As shown in FIG. 2, the control unit 20 includes a CPU 23 as a central processing unit that executes various arithmetic processes, a ROM 24 that stores control programs, a RAM 25 that stores various data, an input / output circuit (I / O) 26, and the like. It is configured as a logical operation circuit composed of bus lines to be connected.

  The power supply unit 10 is provided with three low voltage power supplies (hereinafter referred to as “LVPS”) 13 for supplying power to the control unit 20 and the image forming unit 21. LVPS_1 (13) is a power source that supplies power to the control unit 20, and is turned on even when the power source is set to off. LVPS_2 (13) is also a power source that supplies power to the control unit 20, and is a power source that is turned off in the power saving mode. LVPS_3 (13) is a power source that supplies power to the image forming unit 21, and is turned off in the power saving mode. Note that the power saving mode includes a sleep mode and the like.

  Further, LVPS_2 (13) and LVPS_3 (13) and the control unit 20 are connected by control lines 14 and 15. When the power saving signals output from the control unit 20 to the LVPS_2 (13) and LVPS_3 (13) by the control lines 14 and 15 become high level, the LVPS_2 (13) and LVPS_3 (13) are activated. In the power saving mode, the LVPS_2 (13) and LVPS_3 (13) are turned off by setting the power saving signal to a low level.

  In addition, when a high-level power saving signal is not input to the LVPS_2 (13) and LVPS_3 (13) due to a failure of the control unit 20 or the like, the switches 11 and 12 are turned on by a serviceman or user operation. . The switch 11 is a switch that connects the power line of the LVPS_1 (13) and the control line 14. When the switch 11 is set to ON, the power from the always-on LVPS_1 (13) is input to the startup terminal of the LVPS_2, and the LVPS_2 (13) is started. Similarly, the switch 12 is a switch that connects the power line of the LVPS_1 (13) and the control line 15. When the switch 12 is set to ON, the power from the LVPS_1 (13) is input to the activation terminal of the LVPS_3 (13), and the LVPS_3 (13) is activated. The power supply lines of LVPS_2 (13) and LVPS_3 (13) are connected to these power supply lines, and a display unit 27 is provided to display whether the LVPS_2 (13) and LVPS_3 (13) are in a power output state. ing. The display unit 27 is configured by an LED or the like.

  Thus, in this embodiment, the LVPS_2 (13) and the LVPS_3 (13) can be turned on and off by the switches 11 and 12. Therefore, when the power supply unit 10 does not start up in the power saving mode, a signal for starting the power supply unit 10 is input to easily determine whether the control unit 20 is in failure or the power supply unit 10 is in failure. be able to. Moreover, since the power saving mode is shifted to the power saving mode by setting the power saving signal to a low level, the power consumption in the power saving mode can be reduced.

  In the present embodiment, when the connector 32 connecting the power supply unit 10, the control unit 20, and the image forming unit 21 is disconnected, this is detected and the on / off control signal of the LVPS_2 (13) is forcibly detected. A forced on circuit 30 for turning on is provided. The configuration of the forced on circuit 30 will be described with reference to FIG.

  The forced-on circuit 30 has an emitter connected to the power line 33 of LVPS_1 (13), a base connected to the power line 33 via a dummy wiring 35, a collector 31 grounded, and an input side connected to the emitter. , And a diode 36 connected to the signal line 37 of the on / off control signal on the output side. As shown in FIG. 4, the connector 32 is provided with a dummy wiring 35 for the forced on circuit 30. The dummy wiring 35 is a wiring connecting the output terminal and the input terminal of the connector 32, the output terminal is connected to the power supply line 33 in the power supply unit 10, and the input terminal is connected to the base of the transistor 31 through a resistor. ing. The on / off control signal signal line 37 is a control signal line for setting the LVPS_2 (13) to the power saving mode or starting the power saving mode.

  When the connector 32 is disconnected (step S1), the power from the power supply LVPS_1 (13) is not supplied to the load, and a voltage is applied to the base of the transistor. As a result, the forced on circuit 30 is turned on, the signal line 37 is set to the high level, and the on / off control signal is forcibly set to the high level (step S2). When a high level on / off control signal is input to LVPS_2 (13), LVPS_2 (13) is turned on. By measuring the voltage of the output terminal 34 connected to the LVPS_2 (13) with a tester or the like (step S4), it is possible to confirm the failure of the power supply. If the power supply unit 10 is equipped with more power supplies, a forced on circuit may be provided corresponding to each power supply. Further, if a display unit 27 such as an LED is added to the output terminal 34, it is possible to easily determine the failure of the power source by visual observation.

  In this embodiment, the forced on circuit 30 described in the second embodiment is provided in the interlock circuit. An interlock circuit is used in the image forming apparatus. For example, a dangerous operating state does not occur for the operator by turning on and off the power using a switch linked to opening and closing of the front door of the device. I am doing so. As a result, even if the device is powered on, if the front door is opened, the application of the drive voltage to the load is stopped, that is, the load does not move, causing an accident. Can be prevented.

  As shown in FIG. 6, the interlock circuit includes an interlock switch 41 that switches off and on according to opening and closing of the front door, and a power supply 44 to the output terminal B according to the on and off of the interlock switch 41. And an interlock relay 43 that cuts off the output of. A voltage is constantly applied to the output terminal A. The forced on circuit 50 includes a transistor 51 having an emitter as a power supply line 42, a base as an input side of the interlock switch 41, and a collector as a ground, and a resistor.

  When the front door is opened, the interlock switch 41 is turned off and the output terminal B is cut so that no current flows. At this time, the forcible on circuit 50 is provided to forcibly turn on the interlock relay 43 so that the voltage is applied to the output terminal B. By measuring the voltage at the output terminal B with a tester or the like, it is possible to easily determine the failure of the power supply unit 44. Further, if a display device such as an LED is added to the output terminal B, it is possible to easily determine the failure of the power source only by visual observation.

  In this way, the present embodiment provides a power supply device with high power saving efficiency that can easily diagnose a failure with a simple configuration, shorten the time for repairing the failure, and avoid damage to the customer as well as maintenance costs. I can do it.

  The embodiment described above is a preferred embodiment of the present invention. However, the present invention is not limited to this, and various modifications can be made without departing from the scope of the present invention.

1 is a diagram illustrating a configuration of a power supply device of the present invention and an image forming apparatus equipped with the power supply device. It is a figure which shows the structure of a control part. It is a figure which shows the relationship between the signal voltage of a power saving signal, and the operation mode of a power supply part. It is a figure which shows the structure of 2nd Example of a power supply device. It is a flowchart which shows the operation | movement procedure of the power supply device of 2nd Example. It is a figure which shows the structure which attached the forced ON circuit to the power supply device carrying an interlock circuit.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 10 Power supply part 11, 12 Switch 13 LVPS
14, 15 Control line 20 Control unit 21 Image forming unit 22 Switch 23 CPU
24 ROM
25 RAM
26 I / O
30, 50 Forced ON circuit 31 Transistor 32 Connector 33 Power supply line 34 Output terminal 35 Dummy wiring 36 Diode 37 Signal line 41 Interlock switch 42 Interlock relay

Claims (7)

When a control signal input from an external device is at a low level, the power supply device enters a power saving mode and partially stops power supply. When the control signal becomes high level, the power supply device resumes power supply to the load. There,
A power supply apparatus comprising switching means for forcibly switching the control signal to a high level. The power supply device includes a first power supply unit that supplies power to the load even in the power saving mode, and a second power supply unit that switches on and off by the control signal,
2. The power supply device according to claim 1, wherein the switching unit forcibly switches the control signal to a high level by a power supply from the first power supply unit and restarts the power supply by the second power supply unit.   3. The power supply apparatus according to claim 2, wherein the switching means is a switch for switching on and off a signal line connecting the power line of the first power supply unit and the signal line of the control signal.   The switching means is means for connecting a power supply line of the first power supply unit and a signal line of the control signal when a connector connecting the power supply device and the load is cut. Item 3. The power supply device according to Item 2.   The switching means forcibly turns on a relay of an interlock circuit and outputs the output of the power supply device to an output confirmation terminal when a connector connecting the power supply device and the load is disconnected. The power supply device according to claim 1.   5. The power supply device according to claim 2, further comprising a display unit configured to display whether or not the second power supply unit is in a state in which power can be supplied. When a control signal input from an external device is at a low level, a step of shifting to a power saving mode and partially stopping power supply; and
Resuming power supply to the load when the control signal goes high;
And a step of forcibly switching the control signal to a high level to determine a failure of the power supply device.

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