JP2011188625A - Power unit, image forming apparatus using the same, method and program for controlling the power unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power unit which is high in power saving performance in an energy saving mode. <P>SOLUTION: The power unit 600 has a rectifier 601, an active filter part 603 which boosts the output of the rectifier 601 and outputs a primary DC voltage, and a DC/DC converter 605 which generates a secondary DC voltage from the primary DC voltage. When an operation mode shifts to an energy saving mode, the primary DC voltage Vdc is boosted to approximately double as compared with that at usual operation, and then the active filter part 603 is stopped at operation in the energy saving mode. The energy accumulated in a smoothing capacitor C1 becomes approximately four times as compared with the energy at usual operation. By supplying the energy accumulated in the smoothing capacitor C1 for operation in the energy saving mode, it is possible to operate the DC/DC converter part 605 in a state that there is no power supply from an AC power source 101 for a long time since the active filter part 603 stops, whereby the power consumption in the sleep mode is reduced largely. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a power supply apparatus, an image forming apparatus using the same, a control method for the power supply apparatus, and a control program for the power supply apparatus, and in particular, a power supply apparatus having an active filter, an image forming apparatus using the same, and a control for the power supply apparatus The present invention relates to a method and a control program for a power supply device.

  For example, a power supply used for an image forming apparatus (scanner function, facsimile function, copying function, printer function, data communication function, MFP (Multi Function Peripheral) having a server function, facsimile apparatus, copying machine, printer, etc.) Some devices have an active filter for power factor improvement and harmonic countermeasures.

  Patent Document 1 listed below discloses a power supply device using such an active filter. When the operation mode of the device is the power saving mode (energy saving mode), this power supply device reduces the power consumption by putting the active filter in the operation stop state.

JP 2007-90830 A

  In the power supply device described in Patent Literature 1, since the active filter is simply stopped in the energy saving mode (sleep mode), the energy accumulated in the active filter is small. Therefore, in the energy saving mode, almost no energy is supplied from the active filter to the DC / DC converter unit, and energy is supplied from the commercial power source.

  By the way, in the power supply device as described above, it is desired to further improve the power saving performance in the energy saving mode.

  The present invention has been made in view of such a demand, and provides a power supply device having high power saving performance in the energy saving mode, an image forming apparatus using the power supply device, a control method for the power supply device, and a control program for the power supply device. The purpose is to do.

  In order to achieve the above object, according to one aspect of the present invention, a power supply device that can operate with an energy saving mode that saves power more than when operating under a normal operation mode as an operation mode includes: a rectifying unit that rectifies alternating current; An active filter unit that boosts the output of the rectifier unit and outputs a primary DC voltage; a DC / DC converter unit that generates a secondary DC voltage from the primary DC voltage output from the active filter unit; and an operation mode is a normal operation mode And a filter control unit that boosts the primary DC voltage when compared with the normal operation under the normal operation mode and then stops the active filter unit during the operation under the energy saving mode.

  Preferably, when the operation mode shifts from the normal operation mode to the energy saving mode, the filter control unit boosts the primary DC voltage to approximately twice that in the normal operation under the normal operation mode.

  Preferably, the DC / DC converter unit has a switching element using SiC or GaN.

  According to another aspect of the present invention, an image forming apparatus includes any of the power supply apparatuses described above, and operates using a secondary DC voltage generated by a DC / DC converter unit.

  According to still another aspect of the present invention, the energy saving mode, which saves power compared to the operation under the normal operation mode, can be operated as the operation mode, and the output of the rectifier and the rectifier that rectifies AC The control method of the power supply apparatus including the active filter unit that boosts and outputs the primary DC voltage, and the DC / DC converter unit that generates the secondary DC voltage from the primary DC voltage output from the active filter unit has an operation mode of normal When shifting from the operation mode to the energy saving mode, the primary DC voltage is boosted compared to the normal operation under the normal operation mode, and after the primary DC voltage is boosted by the boost step, And a stop control step for stopping the active filter unit during the operation.

  According to still another aspect of the present invention, the energy saving mode, which saves power compared to the operation under the normal operation mode, can be operated as the operation mode, and the output of the rectifier and the rectifier that rectifies AC The control program of the power supply device including the active filter unit that boosts and outputs the primary DC voltage, and the DC / DC converter unit that generates the secondary DC voltage from the primary DC voltage output from the active filter unit has an operation mode of normal When shifting from the operation mode to the energy saving mode, the primary DC voltage is boosted compared to the normal operation under the normal operation mode, and after the primary DC voltage is boosted by the boost step, And causing the computer to execute a stop control step for stopping the active filter unit during the operation.

  According to these inventions, when the operation mode shifts from the normal operation mode to the energy saving mode, the primary DC voltage output by the active filter unit is boosted compared to the normal operation under the normal operation mode, and then the active filter unit Stopped. Accordingly, it is possible to provide a power supply device having high power saving performance in the energy saving mode, an image forming apparatus using the power supply device, a control method for the power supply device, and a control program for the power supply device.

1 is a side view illustrating a hardware configuration of an image forming apparatus according to one embodiment of the present invention. 1 is a block diagram illustrating a configuration of an image forming apparatus. It is a circuit diagram which shows the structure of a power supply device. It is a flowchart which shows operation | movement of a power supply device.

  Hereinafter, an image forming apparatus according to one embodiment of the present invention will be described.

  The image forming apparatus has a print function for transporting paper or the like by a roller and printing (printing) on the paper or the like by an electrophotographic method, a server function for saving document data or the like in an HDD (Hard Disk Drive), or the like. ing. The image forming apparatus includes a power supply device, and performs various functions using a DC voltage generated from an AC power supply by the power supply device.

  [Embodiment]

  First, the overall configuration of the image forming apparatus according to the present embodiment will be described.

  [Entire configuration of image forming apparatus]

  FIG. 1 is a side view showing a hardware configuration of an image forming apparatus according to one embodiment of the present invention.

  Referring to the figure, the image forming apparatus 1 includes a paper feed cassette 3, a paper discharge tray 5, and a printing unit 30.

  The paper feed cassette 3 is disposed in the lower part of the image forming apparatus 1 so as to be detachable from the housing of the image forming apparatus 1. The paper loaded in each paper feed cassette 3 is fed one by one from the paper feed cassette 3 and sent to the printing unit 30 at the time of printing. The number of paper feed cassettes 3 is not limited to one and may be larger.

  The paper discharge tray 5 is disposed above the housing of the image forming apparatus 1. A sheet on which an image is formed by the printing unit 30 is discharged from the inside of the housing to the discharge tray 5.

  The print unit 30 is disposed inside the housing of the image forming apparatus 1. The printing unit 30 roughly includes a paper transport unit 200, a toner image forming unit 300, a fixing device 400, and a driving unit (shown in FIG. 2) 500. The print unit 30 is configured to be able to form a color image on a sheet by synthesizing four color images of CMYK by a so-called tandem method.

  The paper transport unit 200 includes a paper feed roller 210, a transport roller 220, a paper discharge roller 230, and the like. The paper feed roller 210, the transport roller 220, and the paper discharge roller 230 each transport the paper by rotating the rollers while sandwiching the paper between two opposing rollers, for example. The paper feed roller 210 feeds paper one by one from the paper feed cassette 3. A sheet is fed into the housing of the image forming apparatus 1 by the sheet feeding roller 210. The transport roller 220 transports the paper fed by the paper feed roller 210 to the toner image forming unit 300. Further, the conveyance roller 220 conveys the sheet that has passed through the fixing device 400 to the paper discharge roller 230. The paper discharge roller 230 discharges the paper transported by the transport roller 220 to the outside of the casing of the image forming apparatus 1. In addition to these, the paper transport unit 200 may include rollers that are used to transport paper.

  The toner image forming unit 300 includes four color toner bottles 301Y, 301M, 301C, and 301K (hereinafter, collectively referred to as a toner bottle 301), an intermediate transfer belt 305, a transfer roller 307, and four sets. Development units 310Y, 310M, 310C, and 310K (hereinafter, these may be collectively referred to as development unit 310), a laser scan unit 320, and the like.

  The yellow toner bottle 301Y, the magenta toner bottle 301M, the cyan toner bottle 301C, and the black toner bottle 301K store CMYK toners of yellow (Y), magenta (M), cyan (C), and black (K), respectively. To do.

  The intermediate transfer belt 305 has an annular shape and is stretched between two rollers. The intermediate transfer belt 305 rotates in conjunction with the paper transport unit 200. The transfer roller 307 is disposed so as to face a portion of the intermediate transfer belt 305 that is in contact with one roller. The sheet is conveyed while being sandwiched between the intermediate transfer belt 305 and the transfer roller 307.

  The developing unit 310 includes a photosensitive member 311 (photosensitive members 311Y, 311M, 311C, and 311K are provided for each developing unit), a developing device, a cleaner, a charger, and the like. The yellow developing unit 310Y, the magenta developing unit 310M, the cyan developing unit 310C, and the black developing unit 310K are arranged to form Y, M, C, and K images, respectively. The developing unit 310 is juxtaposed directly below the intermediate transfer belt 305. The laser scan unit 320 is disposed on each photoconductor 311 so as to be able to scan with laser light.

  In the toner image forming unit 300, the laser scanning unit 320 forms a latent image on the photoreceptor 311 that is uniformly charged by the charger based on the image data for each color of YMCK. The developing device forms a toner image for each color on each photoconductor 311. Each photoconductor 311 transfers the toner image to the intermediate transfer belt 305, and forms a mirror image of the toner image formed on the paper on the intermediate transfer belt 305 (primary transfer). Thereafter, the transfer roller 307 to which a high voltage is applied transfers the toner image formed on the intermediate transfer belt 305 to the sheet, and a toner image is formed on the sheet (secondary transfer).

  When the toner in the developing unit 310 decreases due to image formation, the toner stored in the toner bottle 301 of each color is supplied to the developing unit.

  The fixing device 400 includes a heating roller 401 and a pressure roller 403. The fixing device 400 conveys the sheet on which the toner image is formed between the heating roller 401 and the pressure roller 403 while sandwiching the sheet, and heats and presses the sheet. As a result, the fixing device 400 melts the toner adhering to the paper and fixes it on the paper to form an image on the paper. The sheet that has passed through the fixing device 400 is discharged from the casing of the image forming apparatus 1 to the discharge tray 5 by the discharge roller 230.

  The drive unit 500 includes, for example, a main motor 501, a fixing motor 502, a black developing motor 503, a color developing motor 504, and a color photoreceptor motor 505 (hereinafter, these motors are simply referred to as motors 501 to 505, etc.). Sometimes called). The drive unit 500 is driven under the control of a CPU (an example of a filter control unit) 21 (shown in FIG. 2) described later. The main motor 501 carries the paper from the paper feeding process to the transfer process and drives the intermediate transfer belt 305 and the black photoconductor 311K. The fixing motor 502 drives the fixing device 400. The black developing motor 503 drives the black developing unit 310K. A color developing motor 504 drives yellow, magenta, and cyan developing units 310Y, 310M, and 310C. The color photoconductor motor 505 drives the yellow, magenta, and cyan photoconductors 311Y, 311M, and 311C.

  When printing is instructed to the image forming apparatus 1, the sheets stored in the sheet feeding cassette 3 are taken out one by one by the sheet feeding roller 210. The paper is transported by the paper feed roller 210 and the transport roller 220. In parallel with the paper feeding, the charged photoreceptors 311Y, 311M, 311C, 311K are exposed by the laser scan unit 320 based on the image data. A toner image is formed on the photoreceptor 311 by developing with toner in the developing units 310Y, 310M, 310C, and 310K of the respective colors. The toner images formed on the photoreceptors 311 of the respective colors are transferred onto the intermediate transfer belt 305, and toner images for four colors are formed on the intermediate transfer belt 305. Next, a voltage is applied to the transfer roller 307 so that the toner image formed on the intermediate transfer belt 305 is transferred to the conveyed paper. The toner image formed on the paper is fixed on the paper when the paper passes through the fixing device 400 and heat and pressure are applied. The paper on which the toner image is fixed is discharged to the paper discharge tray 3 by the paper discharge roller 230.

  FIG. 2 is a block diagram illustrating a configuration of the image forming apparatus 1.

  Referring to the figure, image forming apparatus 1 further includes an operation unit 11, a control unit (CPU unit) 20, a nonvolatile memory 27, an interface unit 29, and a power supply device 600.

  The operation unit 11 is disposed in the casing of the image forming apparatus 1 so that it can be operated by a user. A display panel 13 is disposed on the operation unit 11. The display panel 13 is, for example, an LCD (Liquid Crystal Display) provided with a touch panel. The display panel 13 displays a guidance screen for the user or displays an operation button to accept a touch operation from the user. The display panel 13 performs display under the control of the CPU 21 of the control unit 20. When the user operates the display panel 13, operation buttons (not shown), or the like, the operation unit 11 transmits an operation signal or a predetermined command corresponding to the operation to the CPU 21. That is, the user can cause the image forming apparatus 1 to execute various operations by operating the operation unit 11.

  The control unit 20 includes a CPU 21, a ROM (Read Only Memory) 23, a RAM (Random Access Memory) 25, and the like. The control unit 20 is connected to the system bus together with the operation unit 11, the nonvolatile memory 27, the interface unit 29, the power supply device 600, and the like. Thereby, the control part 20 and each part of the image forming apparatus 1 are connected so that signals can be transmitted and received.

  The CPU 21 controls various operations of the image forming apparatus 1 by executing a control program 23 a or the like stored in the ROM 23, RAM 25, or nonvolatile memory 27. When an operation signal is sent from the operation unit 11 or an operation command is sent from a client PC or the like, the CPU 21 executes a control program 23a according to them. Thereby, the operation of the image forming apparatus 1 is performed according to the operation of the operation unit 11 by the user.

  The ROM 23 is, for example, a flash ROM (Flash Memory). The ROM 23 stores data used for operating the image forming apparatus 1. Further, the ROM 23 stores a control program (program) 23 a for performing various operations of the image forming apparatus 1. In addition, the ROM 23 may store function setting data of the image forming apparatus 1. The CPU 21 reads data from the ROM 23 and writes data to the ROM 23 by performing predetermined processing. The ROM 23 may be non-rewritable.

  The RAM 25 is a main memory of the CPU 21. The RAM 25 is used for storing data necessary when the CPU 21 executes the control program 23a.

  The nonvolatile memory 27 stores information that needs to be maintained even after the image forming apparatus 1 is turned off, such as information related to the life state such as the number of prints. The nonvolatile memory 27 stores, for example, job data sent from the outside via the interface unit 29. The nonvolatile memory 27 may be configured to store setting information of the image forming apparatus 1 and a control program for performing various operations of the image forming apparatus 1. The nonvolatile memory 27 can store a plurality of jobs transmitted from one client PC or a plurality of client PCs. The nonvolatile memory 27 is composed of, for example, an HDD (Hard Disk Drive), a flash ROM, or the like.

  The interface unit 29 is configured, for example, by combining a hardware unit such as a NIC (Network Interface Card) and a software unit that performs communication using a predetermined communication protocol. The interface unit 29 connects the image forming apparatus 1 to an external network such as a LAN. As a result, the image forming apparatus 1 can communicate with an external apparatus such as a client PC connected to the external network. The image forming apparatus 1 can receive a job from a client PC. Further, the image forming apparatus 1 can transmit the image data to the client PC or by E-mail via a mail server or the like.

  The interface unit 29 may be configured to be connectable to an external network by wireless communication. The interface unit 29 may be, for example, a USB (Universal Serial Bus) interface. In this case, the interface unit 29 enables communication between the external device connected via the communication cable and the image forming apparatus 1.

  The power supply device 600 is provided inside the housing of the image forming apparatus 1. The power supply device 600 is connected to a commercial power supply and supplies power to each unit of the image forming apparatus 1 based on the commercial power supply.

  The developing units 310Y, 310M, 310C, and 310K are provided with nonvolatile memories 319Y, 319M, 319C, and 319K, respectively. The toner bottles 301Y, 301M, 301C, and 301K are provided with nonvolatile memories 309Y, 309M, 309C, and 309K, respectively.

  Since the photoconductor 311 and the like included in the developing unit 310 deteriorate as printing is repeated, the developing unit 310 has a lifetime. Further, since the toner stored in the toner bottle 301 decreases as printing is repeated, the toner bottle 301 has a lifetime. That is, the developing unit 310 and the toner bottle 301 are consumables. The CPU 21 stores information such as the life state of each consumable in these nonvolatile memories 319Y to 319K and 309Y to 309K (hereinafter, these may be collectively referred to as the nonvolatile memory 719). Thereby, even when each consumable is removed and mounted on another image forming apparatus, the life state of the consumable can be reflected in the image forming apparatus of the transfer destination. Therefore, it is possible to reliably manage the life of each consumable and appropriately print an image.

  Here, the image forming apparatus 1 has, as operation modes, for example, a normal operation mode for executing a normal print function and the like, and an energy saving mode (sleep mode) in which power is saved compared with the operation under the normal operation mode. have. When the image forming apparatus 1 operates in the normal operation mode, for example, when the print function or the like is not performed for a predetermined period, the image forming apparatus 1 shifts to the energy saving mode. When the image forming apparatus 1 operates in the energy saving mode, for example, when executing a print function, the image forming apparatus 1 shifts to the normal operation mode. As described above, when the image forming apparatus 1 is temporarily not used, the image forming apparatus 1 is driven in the energy saving mode, so that the power consumption of the image forming apparatus 1 can be reduced.

  [Configuration of Power Supply Device 600]

  Next, the configuration of the power supply apparatus 600 will be described.

  FIG. 3 is a circuit diagram showing a configuration of power supply device 600.

  Referring to the figure, power supply device 600 includes a rectifying unit 601, an active filter unit 603, and a DC / DC converter unit 605. An AC power supply (Vac) 101 is input to the rectifying unit 601. The AC power supply 101 is, for example, a commercial power supply, and is AC100V in Japan.

  The rectifying unit 601 has four diodes D1 to D4. The AC power of the AC power supply 101 is full-wave rectified by the diodes D1 to D4. Thereby, DC power is obtained. The DC power obtained by the rectifying unit 601 is input to the active filter unit 603.

  The active filter unit 603 boosts the output of the rectifying unit 601 and outputs a primary DC voltage (primary DC power supply). The active filter unit 603 brings the input power factor closer to 1 by boosting the primary DC voltage.

  The DC / DC converter unit 605 generates a secondary DC voltage from the primary DC voltage output from the active filter unit 603. By supplying the secondary DC voltage to each part of the image forming apparatus 1 such as the driving unit 500, the image forming apparatus 1 can execute a print function or the like. That is, the image forming apparatus 1 operates using the secondary DC voltage generated by the DC / DC converter unit 605.

  Here, the active filter unit 603 operates as follows. That is, the active filter unit 603 first stores the DC power energy from the rectifying unit 601 in the reactor L1. This is performed by turning on a MOS field effect transistor (MOSFET, an example of a switching element) Q1 connected via the reactor L1 for a predetermined time. Reactor L1 is connected to capacitor C1 through diode D5 and the like. Thereafter, the field effect transistor Q1 is turned off for a predetermined time, and the energy stored in the reactor L1 is stored in the capacitor C1. By repeating this, the power factor is improved.

  The on / off control of the field effect transistor Q1 is performed as follows.

  Referring to the figure, the DC voltage rectified by rectification unit 601 and input to active filter unit 603 is divided by resistors R1 and R2. The alternating current phase signal Vacph obtained by the voltage division is input to the multiplier MUL.

  The voltage Vdc boosted and stored in the capacitor C1 is divided by resistors R4 and R5. A DC feedback voltage signal Vdcfb obtained by voltage division and a predetermined boosted voltage command (DC voltage signal) Vdch * are proportionally integrated and controlled by an amplifier A1. The output Vdcao of the amplifier A1 is input to the multiplier MUL and is multiplied by the alternating current phase signal Vacph.

  The current signal (DC current command) Idc * multiplied and output from the multiplier MUL is detected by the DC current detection resistor R3 connected between the field effect transistor Q1 and the anodes of the diodes D3 and D4. The direct current (DC current feedback signal) Idcfb is proportionally integrated and controlled by the amplifier A2. The comparator CMP1 compares the DC voltage amplifier output Idcao output from the amplifier A2 with a triangular wave oscillator OSC1 serving as a PWM (Pulse Width Modulation) carrier. The comparator CMP1 outputs a Q1 on signal Q1on * which is a PWM duty signal of the field effect transistor Q1.

  The Q1 on signal Q1on * is input to the AND circuit 655 together with the active filter on / off signal PFCC from the CPU 21. The AND circuit 655 takes a logical product of the Q1 on signal Q1on * and the active filter on / off signal PFCC, and outputs an active filter control signal (active filter on signal) PFCON. The active filter control signal PFCON is input to the gate of the field effect transistor Q1. That is, the field effect transistor Q1 is turned on / off using the active filter control signal PFCON as a gate signal.

  Thus, by turning on / off the field effect transistor Q1, the DC voltage Vdc across the capacitor C1 becomes a constant voltage of about 400 V, and an AC input current with a power factor of 1 can be realized.

  The DC / DC converter unit 605 includes a transformer T1, a MOS field effect transistor (an example of a switching element) Q2 connected via the transformer T1, a diode D6 and a capacitor C2 provided on the secondary side of the transformer T1. And have. The DC / DC converter unit 605 performs constant voltage control on the DC voltage Vdc output from the active filter unit 603, that is, the primary DC voltage. The DC / DC converter unit 605 controls the on / off of the field effect transistor Q2, thereby insulating and stepping down and transmitting the primary DC voltage Vdc to the secondary side of the transformer T1. The DC / DC converter unit 605 outputs a constant secondary DC voltage of 24V by controlling the on / off duty of the field effect transistor Q2.

  The AC power supply 101 is also connected to the heater lamp H1 of the fixing device 400. The heater lamp H1 is disposed inside the heating roller 401 and generates heat for fixing the toner on the paper. The AC power supply 101 is connected to the heater lamp H1 via a triac TRIAC. The triac TRIAC is controlled to be turned on / off at zero cross by receiving a triac on signal Tron * from the CPU 21. Thereby, the temperature control of the heater lamp H1 is performed.

  [Operation of power supply device 600 when shifting to energy saving mode]

  Here, in the present embodiment, when the operation mode of the image forming apparatus 1 shifts from the normal operation mode to the energy saving mode, the primary DC voltage Vdc in the power supply device 600 is in the normal operation under the normal operation mode (hereinafter, referred to as the normal operation mode). This may be simply referred to as normal operation). In addition, after the primary DC voltage Vdc is boosted, the active filter unit 603 is stopped when operating in the energy saving mode (hereinafter sometimes referred to as sleep). These controls are performed by the CPU 21 executing the control program 23a.

  Referring to the figure, in active filter unit 603 of power supply device 600, DC voltage addition command Vdcl * can be added to DC voltage signal (DC voltage command) Vdch *. The DC voltage addition signal Vdcl * can be added to the DC voltage signal Vdch * via the switch SW1. The switch SW1 is turned on when the DC voltage addition signal Vdcadd is output from the CPU 21. When the operation mode shifts from the normal operation mode to the energy saving mode, the CPU 21 receives the sleep signal Sleep before shifting to the energy saving mode. When the CPU 21 receives the sleep signal Sleep, it outputs a DC voltage addition signal Vdcadd to the switch SW1. Therefore, when the operation mode shifts from the normal operation mode to the energy saving mode, the DC voltage addition command Vdcl * is added to the DC voltage signal Vdch * before shifting to the energy saving mode.

  When the DC voltage addition command Vdcl * is added to the DC voltage signal Vdch *, the primary DC voltage Vdc rises and becomes a constant voltage of about 800V. That is, the primary DC voltage Vdc is boosted to about twice that of normal operation (about 400 V). The energy stored in the smoothing capacitor C1 is proportional to the square of the voltage. Therefore, when the primary DC voltage Vdc is boosted in this way, the energy stored in the smoothing capacitor C1 is approximately four times the energy during normal operation.

  When the DC voltage addition command Vdcl * is added to the DC voltage signal Vdch * and the operation mode shifts from the normal operation mode to the energy saving mode, the CPU 21 stops the operation of the active filter unit 603. That is, the active filter unit 603 is stopped during sleep.

  In the present embodiment, the DC / DC converter unit 605 following the active filter unit 603 corresponds to a relatively wide input voltage range, and can operate even when a DC voltage of about 800 V is input. The field effect transistor Q1 of the active filter portion 603 may be one using, for example, a SiC or GaN semiconductor. Further, the field effect transistor Q2 of the DC / DC converter unit 605 may be one using, for example, a semiconductor such as SiC or GaN.

  FIG. 4 is a flowchart showing the operation of the power supply apparatus 600.

  In step S101, the AC power supply (Vac) 101 is turned on.

  In step S103, the CPU 21 turns on the active filter on / off signal PFCC (H (high)). As a result, the logical product of the active filter on / off signal PFCC and the Q1 on signal Q1on * by constant voltage control is output to the gate of the field effect transistor Q1, and the active filter unit 603 is turned on.

  In step S105, the active filter unit 603 is turned on, so that the power factor is improved and the primary DC voltage Vdc is controlled to be constant at about 400V.

  In step S107, the CPU 21 detects whether or not the sleep signal Sleep is on.

  If the sleep signal Sleep is not on in step S107, in step S109, the CPU 21 maintains the state if the active filter unit 603 is on, and turns it on if the active filter unit 603 is off. In addition, the CPU 21 performs the process of step S107 again. Thus, if the sleep signal Sleep is not on, the active filter unit 603 is kept on until the sleep signal Sleep is turned on, and the control of the primary DC voltage Vdc is continued.

  If the sleep signal Sleep is on in step S107, in step S111, the CPU 21 detects whether or not the active filter unit 603 is on.

  If the active filter unit 603 is not on in step S111, the process of step S107 is performed again. In this way, when the active filter unit 603 is off, that is, during sleep, the active filter unit 603 is kept off as long as the sleep signal Sleep is on, that is, as long as the sleep state continues.

  If the active filter unit 603 is on in step S111, in step S113, the CPU 21 turns on the DC voltage addition signal Vdcadd (H (high)).

  In step S115, the switch SW1 is turned on when the DC voltage addition signal Vdcadd is turned on. As a result, the DC voltage addition command Vdcl * is added to the amplifier A1.

  In step S117, the DC voltage addition command Vdcl * is added to the amplifier A1, thereby boosting the primary DC voltage Vdc to about 800V while maintaining the power factor.

  In step S119, the CPU 21 turns off the active filter on / off signal PFCC (L (low)). As a result, the active filter unit 603 stops.

  When the process of step S119 ends, the process of step S107 is performed again. That is, the active filter unit 603 is held stopped until the sleep signal Sleep is turned off.

  [Effects of the embodiment]

  In the image forming apparatus configured as described above, when the transition from the normal operation mode to the energy saving mode is performed, the primary DC voltage of the active filter unit is boosted approximately twice, so that the energy stored in the smoothing capacitor, that is, the input energy is approximately 4 times. The active filter unit is stopped in the doubled state. Then, the energy accumulated in the smoothing capacitor is supplied during operation in the energy saving mode, so that the DC / DC converter unit can be operated without power supply from the AC power source for a long time after the active filter unit is stopped. It becomes possible to operate. Therefore, the power consumption at the time of sleep can be significantly reduced, and the power saving performance in the energy saving mode can be further enhanced.

  For example, if the primary DC voltage is constantly boosted to store a large amount of energy in the smoothing capacitor, the active filter unit may generate heat during normal operation or the efficiency of the active filter unit may deteriorate. , It becomes a problem. However, in the image forming apparatus according to the above-described embodiment, the primary DC voltage of the active filter unit is boosted for a relatively short time immediately before shifting to the energy saving mode, and then the active filter unit is stopped. There is no problem with heat generation in the active filter section. The primary DC voltage is boosted during normal operation and does not become a sleep load. Therefore, even when the active filter unit is operated, the efficiency of the power supply is not worse than that during sleep when the active filter unit is stopped.

  [Others]

  The ratio of the primary DC voltage before and after boosting when shifting from the normal operation mode to the energy saving mode is not limited to twice. That is, immediately before shifting to the energy saving mode, the primary DC voltage is boosted to a higher level than before, and the effect of improving the power saving performance in the energy saving mode compared to the case where such control is not performed. can get.

  The image forming apparatus may be any of a monochrome / color copying machine, a printer, a facsimile machine, and the like. The image forming apparatus may be an MFP (Multi Function Peripheral) having a scanner function, a copying function, a printer function, a facsimile function, a data communication function, and a server function. In the scanner function, an image of a set original is read and stored in an HDD or the like. In the copying function, it is further printed (printed) on paper or the like. In the function as a printer, when a print instruction is received from an external terminal such as a PC, printing is performed on a sheet based on the instruction. In the facsimile function, facsimile data is received from an external facsimile machine or the like and stored in an HDD or the like. In the data communication function, data is transmitted / received to / from a connected external device. In the server function, a plurality of users can share data stored in the HDD or the like.

  The image forming apparatus is not limited to an apparatus that forms an image by an electrophotographic method, and may be an apparatus that forms an image by a so-called inkjet method, for example.

  The processing in the above embodiment may be performed by software or by using a hardware circuit.

  A program for executing the processing in the above-described embodiment can be provided, or the program can be recorded on a recording medium such as a CD-ROM, a flexible disk, a hard disk, a ROM, a RAM, or a memory card and provided to the user. It may be. The program may be downloaded to the apparatus via a communication line such as the Internet. The processing described in the text in the above flowchart is executed by the CPU according to the program.

  The present invention is not limited to an image forming apparatus, and can be widely applied to a power supply apparatus having an active filter unit as shown in the above-described embodiments and various apparatuses using the power supply apparatus.

  The above embodiment should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 20 Control part 21 CPU (an example of a filter control part)
23a Control program 101 AC power supply 400 Fixing device 600 Power supply device 601 Rectification unit 603 Active filter unit 605 DC / DC converter unit Vdc Primary DC voltage

Claims (6)

It is a power supply device that can operate with an energy saving mode that saves power more than when operating under a normal operation mode as an operation mode,
A rectifying unit that rectifies alternating current;
An active filter that boosts the output of the rectifier and outputs a primary DC voltage;
A DC / DC converter unit that generates a secondary DC voltage from the primary DC voltage output from the active filter unit;
When the operation mode shifts from the normal operation mode to the energy saving mode, the primary DC voltage is boosted compared to the normal operation under the normal operation mode, and then the active DC is activated during the operation under the energy saving mode. And a filter control unit that stops the filter unit.   2. The filter controller according to claim 1, wherein when the operation mode shifts from the normal operation mode to the energy saving mode, the filter control unit boosts the primary DC voltage to approximately twice that in normal operation under the normal operation mode. The power supply described.   The power supply apparatus according to claim 1, wherein the DC / DC converter unit includes a switching element using SiC or GaN. A power supply device according to any one of claims 1 to 3,
An image forming apparatus that operates using a secondary DC voltage generated by the DC / DC converter unit. It is possible to operate with the energy-saving mode, which saves more power than when operating under normal operating mode,
A rectifying unit that rectifies alternating current;
An active filter that boosts the output of the rectifier and outputs a primary DC voltage;
A control method of a power supply device comprising: a DC / DC converter unit that generates a secondary DC voltage from a primary DC voltage output from the active filter unit,
When the operation mode shifts from the normal operation mode to the energy saving mode, the step-up control step of boosting the primary DC voltage than during normal operation under the normal operation mode;
A control method for a power supply device comprising: a stop control step of stopping the active filter unit during operation under the energy saving mode after the primary DC voltage is boosted by the boosting step. It is possible to operate with the energy-saving mode, which saves more power than when operating under normal operating mode,
A rectifying unit that rectifies alternating current;
An active filter that boosts the output of the rectifier and outputs a primary DC voltage;
A control program for a power supply device comprising a DC / DC converter unit that generates a secondary DC voltage from a primary DC voltage output from the active filter unit,
When the operation mode shifts from the normal operation mode to the energy saving mode, the step-up control step of boosting the primary DC voltage than during normal operation under the normal operation mode;
A control program for a power supply apparatus, which causes a computer to execute a stop control step of stopping the active filter unit when operating under the energy saving mode after the primary DC voltage is boosted by the boosting step.

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