JP5376929B2 - Power supply apparatus and image forming apparatus - Google Patents

Description

  The present invention relates to a power supply device and an image forming apparatus equipped with the power supply device, and more particularly to a power supply device operable in a normal power mode and a power saving mode with less power consumption, and an image forming device equipped with the power supply device. About.

  2. Description of the Related Art Conventionally, in an image forming apparatus such as a copying machine, attention is focused on how to reduce power consumption when an image forming operation is not performed in order to save power. For example, there is a case in which a power supply device that saves power by shifting to a power saving mode in which power is not supplied from the main power supply in some cases where an image forming operation is not performed has been employed.

  However, depending on the intended use and functions of the image forming device, the power supply from the main power supply circuit is always resumed in response to a signal from the outside or the main body operation unit while saving power, and image formation is performed. It will be necessary to return to a possible state.

For example, in a facsimile, it is necessary to be prepared to always receive information input from the outside via a telephone line. In the case of a printer, it is necessary to immediately return to a state where image formation can be performed by receiving an image print command input from a personal computer or the like, and to perform image formation processing based on the received image data. There is. Further, even when the user operates the operation unit of the apparatus to generate a copy image, it is necessary to immediately return to a state in which image formation can be performed and to read an original and perform image formation processing.
That is, the power supply device used for such an image forming apparatus needs to restart the supply of power from the main power supply in order to return to a state in which image formation can be performed while achieving power consumption in the power saving mode. .

Therefore, the conventional power supply apparatus has a configuration as shown in FIG. A main power source 802 and a night power source 801 are provided, and in a power saving state, the power supply from the main power supply device 802 to the first load 806 serving as the image formation control unit is stopped while the SW 2 is turned off. The night power source 801 maintained the power supply to the second load 807. The night-time power supply 801 supplies power to a communication detection unit 808 that monitors a signal from the external device 812 and a communication control unit 809 that controls communication with the external device 812. The night power supply 801 also supplies power to a UI detection unit 810 that detects that the operation unit of the apparatus has been operated and a UI control unit 811 that controls the operation unit. According to this, it is said that it is possible to save power while preparing a system that can always detect a communication signal from the external device 812 and operation of the operation unit and shift to a state where image formation can be performed. It was. (For example, refer to Patent Document 1).
Japanese Patent Laid-Open No. 2004-230643

  However, in the conventional power supply device, the power consumed by the second load 807 is, in the power saving mode, the communication detection unit 808 that monitors the communication signal from the external device 812 and the operation status of the operation unit of the device, and the device. Only the signal input detection unit 808 that detects the operation status of the operation unit is provided. However, after returning from the power saving mode, power is supplied to other than the signal input detection unit. For this reason, the power consumption has greatly increased after the return compared to the power saving mode.

  In addition, the power is supplied to the second load 807 only by the night-time power source 801 in any state in which image formation can be performed, in the image forming operation, and in the power saving mode. Therefore, the night-time power supply 801 is in a state where image formation can be performed and a power supply capable of supplying necessary power with the second load 807 during the image forming operation.

  If the power supply apparatus has a large power supply capability, the basic loss of the apparatus becomes large. Therefore, it has been difficult to sufficiently reduce the power consumption of the power supply apparatus in the power saving mode of the image forming apparatus.

  In order to solve the above problems, a power supply apparatus according to the present invention operates in the normal power mode in a power supply apparatus for a device having a normal power mode and a power saving mode that consumes less power than the normal power mode. The first power source, the second power source that operates in both the normal power mode and the power saving mode, and has a lower power supply capability than the first power source, and the normal power mode. Power is supplied from the first power source to the first load and the second load that consumes less power than the first load, and power is supplied from the second power source to the second load. The power saving mode Sometimes, the first power source is connected to the first load and the second load without being supplied with power, and the second power source is connected to supply power to the second load. And

  According to the present invention, in the normal power mode, power is supplied not only from the second power source that supplies power to the second load that operates in the power saving mode but also from the first power source to the second load. Therefore, it is possible to use the second power source that has a lower power supply capability than the conventional method. Furthermore, it is possible to reduce power consumption in the power saving mode and to reduce the size of the second power supply.

  Hereinafter, an image forming apparatus including a power supply device according to the present invention will be described in detail with reference to the drawings.

(First embodiment)
FIG. 1 is a schematic configuration diagram of an electrophotographic process image forming apparatus equipped with a power supply apparatus according to the present invention.

  In the figure, reference numerals 1a to 1d are photosensitive members, 2a to 2d are primary charging units, 3a to 3d are exposure units, 4a to 4d are development units, 53a to 53d are primary transfer units, 6a to 6d are cleaners, 51 Is an intermediate transfer belt, 55 is an intermediate transfer belt cleaner, and 56 and 57 are secondary transfer unit rollers. After the photosensitive member is uniformly charged by the primary charging unit 53, exposure according to the image signal is performed by the exposure unit 3, whereby an electrostatic latent image is formed on the photosensitive member 1. Thereafter, the toner image is developed by the developing unit 4, and the toner images on the four photoconductors are multiplex-transferred to the intermediate transfer belt by the primary transfer unit 53, and further transferred to the recording paper P by the secondary transfer rollers 56 and 57. Is done. The transfer residual toner remaining on the photoreceptor is recovered by a cleaner, and the transfer residual toner remaining on the intermediate transfer belt 51 is recovered by an intermediate transfer belt cleaner 55. The toner image transferred to the recording paper P is fixed by the fixing unit 7 to obtain a color image.

  FIG. 2 is a configuration diagram of the power supply device.

  The power supply apparatus according to this embodiment includes a main power supply device 202, a main body power switch SW1, a changeover switch SW2, a first control unit 206, a second control unit 207, an overnight power supply device 201, and a current detection circuit 203. Yes. The first control unit mainly controls image forming processing. The second control unit performs communication control with the external device 212 and control of the operation unit (UI) 213. The second control unit 207 further includes a signal input detection unit that detects whether a print job is input from the external device 212, an input of a power saving mode cancellation signal input from the operation unit 213, an image formation start instruction, or the like. 208. Moreover, the 1st control part 206 is a 1st load with respect to a power supply, and a 2nd control part is a 2nd load.

  The power supply capability of the main power supply 202 as the first power supply is about 200 W, and the power supply capability of the night power supply 201 as the second power supply having a lower power supply capability than the first power supply is about 1 W. The night-time power supply device 201 is configured as a unit independent of the main power supply device 202, and the input side is connected to the AC power supply AC via the main body power switch SW1, and generates a predetermined DC voltage with the power from the AC power supply AC. To do. The output side of the night power supply 201 is connected to the second control unit 207. The main power supply device 202 is connected to the first control unit 206 and is also connected to the second control unit 207 via a backflow prevention diode D201.

  FIG. 3 is a block diagram showing the configuration of the night-time power supply device 201.

  The night-time power supply device 201 includes a rectifying / smoothing circuit 301, a switching unit 302, a transformer 303, a rectifying / smoothing circuit 305, a voltage detection circuit 306, an insulated signal transmission element 307, and a control circuit 308. The night-time power supply apparatus 201 constitutes a so-called switching regulator type power supply circuit.

  An AC voltage is input to the rectifying / smoothing circuit 301 from the AC power supply 204. The rectifying / smoothing circuit 301 rectifies and smoothes the input AC voltage and supplies it to the switching unit 302. The switching unit 302 switches the voltage rectified and smoothed by the rectifying and smoothing circuit 301 according to the switching pulse from the control circuit 308 and supplies the voltage to the primary side winding of the transformer 303.

  The voltage generated in the secondary winding of the transformer 303 is supplied to the rectifying / smoothing circuit 305, and the rectifying / smoothing circuit 305 rectifies and smoothes the voltage generated in the secondary winding of the transformer 303 and outputs a DC voltage. . This DC output is supplied to the second control unit 207.

  The voltage detection circuit 306 detects the output voltage value of the rectifying / smoothing circuit 305 and outputs a signal corresponding to the detected output voltage level to the insulation type signal transmission element 307. The insulated signal transmission element 307 transmits the signal from the voltage detection circuit 306 to the power supply control circuit 308 on the primary side of the transformer 303. The pulse width of the switching pulse supplied to the switching unit 302 is controlled according to the signal level transmitted to the power supply control circuit 308.

  When the output voltage of the rectifying / smoothing circuit 305 increases, the power supply control circuit 308 performs control so that the switching pulse width is decreased and the output voltage of the transformer 303 is decreased. Further, when the output voltage of the rectifying / smoothing circuit 305 decreases, the power supply control circuit 308 performs control to increase the switching pulse width and increase the output voltage of the transformer 303.

  Next, power supply control in this embodiment will be described with reference to the flowchart of FIG. The process of this flowchart is executed by the second control unit.

  When the main body power switch SW1 is turned on, the image forming apparatus is activated in the normal power mode, and the second control unit 207 outputs an on signal for turning on the changeover switch SW2 (S401). As a result, the changeover switch SW2 is turned on. When the changeover switch SW2 is turned on, power is supplied from the AC power supply AC to the main power supply device 202, so that power supply from the main power supply device 202 to the first control unit 206 is performed. In parallel with this, power is also supplied from the main power supply device 202 to the second control unit 207 via the diode D201.

  The second control unit 207 requires a total power of about 10 W in order to communicate with the external device 212 and control the operation unit 213. The power supply capability of the night power supply 201 is about 1 W as described above, and the power required by the second control unit 207 in the normal power mode cannot be supplied by the night power supply 201 alone. Power is also supplied from 202.

  The main power supply device 202 receives the output current detection signal I_SENCE of the night power supply device 201 detected by the current detection circuit 203. The main power supply device 202 receives the output current detection signal I_SENCE of the night power supply device 201 and controls its output voltage so that the power supplied from the night power supply to the second control unit is about 1 W. In this way, the main power supply device 202 can supply power that exceeds the supply capacity of the nighttime power supply device 201.

  In the normal power mode, the second control unit 207 receives an input of a print instruction or FAX reception from the external device 212 or an image formation instruction from the operation unit 213 via the signal input detection unit 208 (these are called JOB signals). It is detected whether or not there is (S402). If the above-mentioned JOB signal is not received from the external device 212 for the time T, the second control unit 207 outputs a power saving mode transition signal to the first control unit 206 (S403), and further turns off SW2. The power is pushed (S404). As a result, the image forming apparatus shifts from the normal power mode to the power saving mode.

  When the change-over switch SW2 is in the OFF state, the power supply from the AC power supply AC to the main power supply device 202 is interrupted, so that the power supply from the main power supply device 202 to the first control unit 206 is not performed. At this time, power supply from the AC power supply AC to the night power supply device 201 is continuously performed, and a DC voltage is supplied from the night power supply device 201 to the second control unit 207. At this time, the second control unit 207 operates only the signal input detection unit 208 that detects whether or not a signal from the external device 212 or the operation unit 213 is input, and the power consumption is reduced to a low value of 1 W or less. It is suppressed. Therefore, the night-time power supply device 201 can be configured with a small capacity capable of supplying about 1 W of power.

  In the power saving mode, when the second control unit 207 detects a JOB signal from the external device 212 or the operation unit 213, the second control unit 207 outputs a signal for turning on the switch SW2 (S406). As a result, the main power supply device 202 starts up and the first control unit 206 starts operating. The second control unit 207 notifies the first control unit 206 that the first control unit 206 has shifted to the normal power mode and has received a job signal after the time required for the first control unit 206 to start up normally (S407).

  By the way, in the normal power mode, the supply of the AC power supply AC to the nighttime power supply device 201 is cut off, the output of the nighttime power supply device 201 is stopped, and power is supplied to the second control unit 207 only from the main power supply device 202. It is also possible to adopt a configuration for supplying. However, at the time of transition from the power saving mode to the normal power mode and from the normal power mode to the power saving mode, it is conceivable that the output voltage decreases due to a delay in the rise time of the output in each power supply device, causing the device to malfunction. For this reason, in this embodiment, even in the normal power mode, the power supply from the AC power supply AC to the night power supply device 201 is not cut off, and the output of the night power supply device 201 is not stopped.

(Second Embodiment)
FIG. 5 is a configuration diagram of the power supply apparatus according to the embodiment of the present invention.

  The second embodiment differs from the first embodiment in the following points. That is, in the first embodiment, power is directly supplied from the main power supply device 202 to the second control unit 207 via the diode D201 in the normal operation mode. However, in the second embodiment, a voltage obtained by converting the output voltage of the main power supply device 202 from the main power supply device 202 via the DCDC converter 514 is supplied to the second control unit 207 via the diode D201. .

  For example, when the voltage value to be supplied to the second control unit 207 is different from the voltage value supplied to the first control unit 206, the output voltage of the main power supply device 202 should be supplied to the second control unit 207 by the DCDC converter 514. Convert to voltage value.

  The output current detection signal I_SENCE of the nighttime power supply device 201 detected by the current detection circuit 203 is input to the DCDC converter 514. The DCDC converter 514 controls the output voltage based on the output current detection signal I_SENCE of the nighttime power supply apparatus 201 so that the power supplied from the nighttime power supply to the second control unit 207 is about 1 W. For example, this embodiment is effective when the first control unit operates at 12V and the second control unit operates at 3.3V. As a result, the main power supply device 202 can supplement the power that cannot be provided by the nighttime power supply device 201 alone in the normal power mode.

  Since other configurations are the same as those of the first embodiment, detailed description thereof is omitted. The operation of the second control unit is also as shown in FIG. 4 of the first embodiment.

(Third embodiment)
FIG. 6 is a configuration diagram of a power supply apparatus according to the third embodiment.

  The third embodiment differs from the first embodiment in the following points. That is, in the first embodiment, the main power supply device 202 controls the output voltage while detecting the output current detection signal I_SENCE of the nighttime power supply device 201. However, in the third embodiment, the main power supply device 202 detects the output voltage V_SENCE of the nighttime power supply device 201 to control the output voltage, and performs the second control through the diode D201 and the resistor R601 connected in series. Power is supplied to the unit 207. That is, the main power supply 202 receives the output voltage detection signal V_SENCE of the nighttime power supply 201. The main power supply device controls the output voltage V1 of the main power supply device to be slightly higher than the output voltage of the power supply device 201 in consideration of the forward voltage of the diode D201 and the voltage drop due to the resistor R601. .

  By the way, in the configuration shown in FIG. 6, if there is no resistor R601, the output voltage value of the main power supply device 202 is set to a voltage value slightly higher than the output voltage value of the overnight power supply device 201 than the forward voltage drop voltage of the diode D201. Is set to a value obtained by adding. In that case, all of the power supply to the second control unit 207 in the normal power mode is performed from the main power supply device 202. That is, the night-time power supply device 201 is almost in a no-load state in the normal power mode.

  FIG. 7 is a diagram showing voltage waveforms input to the second control unit 207 before and after switching from the normal power mode to the power saving mode.

  For example, when there is no resistor R601 in the configuration shown in FIG. 6, in the normal power mode, the output voltage value V1 of the main power supply device 202 is slightly smaller than the output voltage value of the nighttime power supply device 201 (input unit of the second control unit 207) V2. It is controlled to be higher. For this reason, the output current value I2 from the nighttime power supply device 201 is zero. On the other hand, the current I1 supplied from the main power supply device 202 to the second control unit 207 in the normal power mode is all the current values Ib required by the second control unit 207.

  When the normal power mode is shifted to the power saving mode in this state and the switch SW2 is turned off from the ON state at the timing T1, the power supply device 201 supplies the current Ia necessary for the second control unit 207 from the almost no load state. Will be responsible. In this case, the control of stabilizing the output voltage of the nighttime power supply device 201 cannot catch up with the sudden change (increase) in the load, and the voltage of V2 (dotted line portion) fluctuates temporarily as shown in FIG. However, the device may malfunction.

  On the other hand, by providing a resistor R601 in series with the diode D201 as shown in FIG. 6, a temporary decrease in the voltage V2 shown in FIG. 7A is prevented as much as possible.

  The configuration for this will be described below. For example, the output voltage value from the main power supply device 202 is V1, the voltage value of the input unit of the second control unit 207 is V2, the output current value of the main power supply device 202 is I1, the forward voltage drop of the diode D201 is VF, The resistance value of the resistor R601 is R1. In this case, if a current greater than or equal to the current value I1 satisfying V2 = V1−I1 * R1−VF is supplied from the main power supply device 202 to the second control unit 207, the second power supply device 201 can obtain the second power even in the normal power mode. Electric power is supplied to the control unit 207.

  FIG. 7B shows waveforms of voltage and current supplied to the second control unit when appropriate resistance values are provided. Assuming that the value of the current I1 flowing through the diode D201 and the resistor R601 is Ic, in the normal power mode, V2 = V1−I1 * R1−VF is satisfied, and the current value Ia from the power supply apparatus 201 to the second control unit 207 is What is necessary is just to set the value of resistance R601 so that it may flow. By setting the value of the resistor R601 in this way, as shown in FIG. 7B, even if the mode is switched to the power saving mode at the timing T1, the voltage V2 can be prevented from temporarily decreasing. Further, it is not necessary to provide a current detection circuit in order to adjust the output current value of the nighttime power supply apparatus 201 as in the first embodiment.

  Since other configurations are the same as those of the first embodiment, the description thereof is omitted.

  In the present embodiment, the output of the main power supply device 202 is directly supplied to the second control unit 207 via the diode D201 and the resistor R601. However, it can also be realized by a configuration using a DCDC converter between the main power supply device 202 and the second control unit 207 as in the second embodiment.

  In the present embodiment, the resistor R601 is connected to the cathode side of the diode D201, but may be connected to the anode side of the diode D201.

1 is a schematic configuration diagram of an image forming apparatus. It is a block diagram of the electric power supply apparatus in the 1st Embodiment of this invention. It is a block block diagram of a nighttime power supply. It is a control flowchart of an electric power supply apparatus. It is a block diagram of the electric power supply apparatus in the 2nd Embodiment of this invention. It is a block diagram of the electric power supply apparatus in the 3rd Embodiment of this invention. It is the voltage and electric current waveform input into the 2nd control part before and behind switching from a normal power mode to a power saving mode. It is a block diagram of a power supply device of a conventional image forming apparatus.

Explanation of symbols

201 Power Supply Device for Nighttime 202 Main Power Supply Device 203 Current Detection Circuit 206 First Control Unit 207 Second Control Unit 208 Signal Input Detection Unit 514 DCDC Converter AC AC Power Supply D201 Diode SW2 Switch R601 Resistance

Claims (8)

In a power supply apparatus for a device having a normal power mode and a power saving mode with less power consumption than the normal power mode,
A first power source that operates in the normal power mode;
A second power source that operates in both the normal power mode and the power saving mode, and has a power supply capability lower than that of the first power source;
In the normal power mode, power is supplied from the first power source to the first load and the second load that consumes less power than the first load, and power is supplied from the second power source to the second load. In the power saving mode, power is not supplied from the first power source to the first load and the second load, and power is supplied from the second power source to the second load. A power supply device characterized by being connected as described above.   The power supply apparatus according to claim 1, wherein power is supplied from the first power source to the second load via a diode for preventing backflow. Current detection means for detecting a current flowing from the second power supply to the second load, wherein the first power supply controls an output voltage of the first power supply based on an output of the current detection means; The power supply device according to claim 1 , wherein the power supply device is a power supply device. Wherein said first power supply is provided between the second to the load, the power according to any one of claims 1 to 3, characterized in that it comprises a converter for converting an output of said first power supply Feeding device.   3. The power supply apparatus according to claim 2, wherein power is supplied from the first power source to the second load via a diode for preventing backflow and a resistor connected in series to the diode.   6. The electric power according to claim 5, wherein the first power supply detects an output voltage of the second power supply, and controls the output voltage of the first power supply to be higher than the detected voltage. Feeding device. An image forming apparatus comprising the power supply device according to any one of claims 1 to 6. The image forming apparatus according to claim 7, wherein the second load includes a unit that detects an input of an image forming job signal.

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