Power supply apparatus and image processing apparatus

Abstract

To provide a power supply apparatus and an image processing apparatus with which stabilization of operation is easily achieved.SOLUTION: A power supply apparatus 3 comprises: a power factor improvement circuit 33; a first voltage conversion unit 31; a second voltage conversion unit 32; a stop control unit 35; and a discharge circuit 36. The power factor improvement circuit 33 outputs a DC voltage obtained by rectifying an AC voltage Vs1 as a predetermined primary voltage Vp1. The first voltage conversion unit 31 converts the primary voltage Vp1 into a first DC voltage Vo1 and outputs the first DC voltage Vo1. The second voltage conversion unit 32 converts the primary voltage Vp1 into a second DC voltage Vo2 and outputs the second DC voltage Vo2. The stop control unit 35 stops output of the first voltage conversion unit 31 and output of the second voltage conversion unit 32 based on a magnitude of the AC voltage Vs1. The discharge circuit 36 causes discharge from a power storage unit C1 charged by the primary voltage Vp1, thereby lowering the primary voltage Vp1.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a power supply device and an image processing device. [Background technology]

[0002] As a related art, a power supply device including a power factor correction circuit is known (see, for example, Patent Document 1). The power supply device of the related art includes a power factor correction circuit that receives a voltage obtained by rectifying an AC voltage from a commercial AC power supply using a rectifier circuit, and supplies the voltage to a load as a predetermined DC voltage through switching control, and a PFC control unit that controls the power factor correction circuit.

[0003] The power factor correction circuit includes a choke coil, a transistor, a diode, a capacitor, and a current detection unit. The PFC control unit receives an input voltage monitoring signal, an output voltage monitoring signal, and an input current monitoring signal and controls the on / off of the transistor. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-115088 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in some situations, the power supply device according to the related art described above may not be able to correctly detect the AC voltage (input voltage) to the power factor correction circuit, which may cause the operation of the power supply device to become unstable.

[0006] An object of the present invention is to provide a power supply device and an image processing device that can easily stabilize their operation. [Means for solving the problem]

[0007] A power supply device according to one aspect of the present invention includes a power factor correction circuit, a first voltage conversion unit, a second voltage conversion unit, a stop control unit, and a discharge circuit. The power factor correction circuit outputs a DC voltage obtained by rectifying an AC voltage as a predetermined primary voltage. The first voltage conversion unit converts the primary voltage into a first DC voltage and outputs the first DC voltage. The second voltage conversion unit converts the primary voltage into a second DC voltage and outputs the second DC voltage. The stop control unit stops the output of the first voltage conversion unit and the second voltage conversion unit based on the magnitude of the AC voltage. The discharge circuit discharges a power storage unit charged by the primary voltage, thereby reducing the primary voltage.

[0008] An image processing device according to another aspect of the present invention includes the power supply device described above and a main body having an image processing function. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a power supply device and an image processing device that can easily stabilize their operation. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic block diagram of an image processing device according to the first embodiment. [Figure 2] FIG. 2 is a schematic diagram showing the appearance of the image processing device according to the first embodiment. [Figure 3] FIG. 3 is a schematic block diagram illustrating an example of a power supply device of the image processing apparatus according to the first embodiment. [Figure 4] FIG. 4 is a schematic circuit diagram showing a specific example of the power supply device of the image processing apparatus according to the first embodiment. [Figure 5] FIG. 5 is a schematic circuit diagram showing a specific example of an output control unit of the power supply device of the image processing apparatus according to the first embodiment. [Figure 6] FIG. 6 is a table showing an example of the operation of the power supply device of the image processing apparatus according to the first embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following description will discuss preferred embodiments of the present invention with reference to the accompanying drawings. The preferred embodiments are merely examples of the present invention and are not intended to limit the technical scope of the present invention.

[0012] (Embodiment 1) [1] Overall configuration of image processing device First, the overall configuration of an image processing device 10 according to this embodiment will be described with reference to FIGS.

[0013] The image processing device 10 according to this embodiment is, for example, a multifunction peripheral having multiple functions, such as a scanning function for acquiring image data from an original, a printing function for forming an image based on the image data, a facsimile function, and a copying function. The image processing device 10 may be a printer, scanner, facsimile machine, copier, etc., as long as it has an image processing function including at least one of the function for forming an image and the function for acquiring image data.

[0014] As shown in Fig. 1, the image processing device 10 includes an automatic document feeder 11, an image reading unit 12, an image forming unit 13, a paper feeder 14, an operation and display unit 15, a main body control unit 16, and a power supply unit 3. The automatic document feeder 11 is an ADF (Auto Document Feeder), and is therefore represented as "ADF" in Fig. 1, and will also be referred to as "ADF 11" in the following description. In this embodiment, as shown in Fig. 2, the image processing device 10 includes a housing 101. The ADF 11, the image reading unit 12, the image forming unit 13, the paper feeder 14, the operation and display unit 15, the main body control unit 16, and the power supply unit 3 are provided in the housing 101.

[0015] The image processing device 10 includes a main body 1 having an image processing function. The main body 1 is provided with an ADF 11, an image reading unit 12, an image forming unit 13, a paper feed unit 14, an operation display unit 15, and a main body control unit 16. In other words, the image processing device 10 includes the main body 1 having an image processing function and a power supply device 3.

[0016] The ADF 11 transports a document whose image is to be read by the image reading unit 12. The ADF 11 includes a document setting unit, a plurality of transport rollers, a document holder, a paper discharge unit, and the like.

[0017] The image reading unit 12 reads an image from a document and outputs image data corresponding to the read image. The image reading unit 12 includes a document table, a light source, a plurality of mirrors, an optical lens, a CCD (Charge Coupled Device), and the like.

[0018] The image forming unit 13 forms an image on a sheet by electrophotography based on image data output from the image reading unit 12. The image forming unit 13 also forms an image on a sheet based on image data input from an information processing device external to the image processing device 10, such as a personal computer.

[0019] Image forming section 13 has four image forming units corresponding to the four colors of C (cyan), M (magenta), Y (yellow), and K (black), an optical scanning device, an intermediate transfer belt, a secondary transfer roller, a fixing device, a developing device, etc. Each image forming unit has a photosensitive drum, a charging roller, a primary transfer roller, a drum cleaning unit, etc. Image forming section 13 may be configured to form an image on a sheet by an image forming method other than the electrophotographic method, such as an inkjet method.

[0020] The image forming unit 13 forms an image on a sheet using toner as a developer. Specifically, the surface of the photosensitive drum, which has been charged by a charging roller, is irradiated with laser light based on image data from an optical scanning device. This forms an electrostatic latent image on the surface of the photosensitive drum. The developing device has a developing roller, a magnet roller, etc., and performs a developing process to develop the electrostatic latent image formed on the surface of the photosensitive drum. When the image forming unit 13 forms an image using an inkjet method, ink (another example of a developer) is supplied instead of toner. After the image formation in the image forming unit 13, the sheet is discharged (supplied) to an auxiliary device or the like for post-processing.

[0021] The paper feed unit 14 supplies sheets to the image forming unit 13. The paper feed unit 14 has a paper feed cassette, a manual feed tray, a sheet transport path, a plurality of transport rollers, etc. The image forming unit 13 forms an image on the sheets supplied from the paper feed unit 14. The sheets supplied to the image forming unit 13 are, for example, paper, but are not limited to paper and may be, for example, a resin film, etc.

[0022] The operation display unit 15 is a user interface in the image processing device 10. The operation display unit 15 has a display unit such as a liquid crystal display that displays various information in response to control instructions from the control unit of the main body, and an operation unit such as a switch or touch panel that inputs various information to the control unit of the main body in response to user operations. Furthermore, the image processing device 10 may also have, in addition to or instead of the operation display unit 15, an audio output unit, an audio input unit, etc. as a user interface.

[0023] The main body control unit 16 mainly comprises a computer system having one or more processors and one or more memories, and performs overall control of the image processing device 10. In the image processing device 10, the one or more processors execute programs to realize the functions of the main body control unit 16. In this embodiment, as an example, the main body control unit 16 includes a CPU (Central Processing Unit).

[0024] The power supply device 3 is a device that generates (outputs) power for the operation of the image processing device 10. The power supply device 3 is electrically connected to one or more electrical loads and supplies power to the one or more electrical loads. In this embodiment, the main body 1 of the image processing device 10 is the "electrical load," and the power supply device 3 supplies power to each part of the main body 1 as the electrical load. In other words, the one or more electrical loads that receive power from the power supply device 3 include the ADF 11, image reading unit 12, image forming unit 13, paper feed unit 14, operation display unit 15, and main body control unit 16. In this way, the image processing device 10 includes the power supply device 3 and the main body 1 that has an image processing function.

[0025] In this embodiment, the power supply device 3 is electrically connected to an AC plug and converts an AC voltage of 100V (or 200V) applied to the AC plug into, for example, a DC voltage of 24V and a DC voltage of 3.3V (or 5V). In other words, when the AC plug is connected to an outlet (power socket), AC power is applied to the power supply device 3 from an AC power source such as a system power supply, and the power supply device 3 generates DC power from this AC power.

[0026] The power supply device 3 supplies a DC 24V voltage to a "second load" such as the ADF 11, the image reading unit 12, and the image forming unit 13. On the other hand, the power supply device 3 supplies a DC 3.3V (or 5V) voltage to a "first load" such as the main body control unit 16.

[0027] The power supply device 3, for example, receives a control signal from the main body control unit 16 and determines the state of power supply to one or more electrical loads (ADF 11, image reading unit 12, image forming unit 13, paper feed unit 14, operation display unit 15, main body control unit 16, etc.). Specifically, the main body 1 has multiple operating modes including a normal mode and an energy-saving mode. The energy-saving mode is a mode in which power consumption in the main body 1 is reduced compared to the normal mode. When the main body 1 operates in the normal mode, the power supply device 3 supplies power to both the first load (main body control unit 16, etc.) and the second load (ADF 11, etc.). On the other hand, when the main body 1 operates in the energy-saving mode, the power supply device 3 supplies power only to the first load of the first and second loads. Therefore, in the energy-saving mode, the main body control unit 16 outputs a control signal (sleep signal) to the power supply device 3 to switch the state of power supply from the power supply device 3.

[0028] The image processing device 10 further includes a storage unit, a communication unit, etc. The storage unit includes one or more non-volatile memories, and pre-stores information such as control programs for causing the main body control unit 16 to execute various processes. The communication unit is an interface that executes data communication between the image processing device 10 and an external device connected via a communication network such as the Internet or a LAN (Local Area Network).

[0029] Incidentally, a power supply device including a power factor correction circuit is known as a related technology for a power supply device used in this type of image processing device 10. The power supply device of the related technology includes a power factor correction circuit that receives a voltage obtained by rectifying AC voltage from a commercial AC power supply using a rectifier circuit, and supplies the voltage to a load as a predetermined DC voltage through switching control, and a PFC control unit that controls the power factor correction circuit.

[0030] The power factor correction circuit includes a choke coil, a transistor, a diode, a capacitor, and a current detection unit. The PFC control unit receives an input voltage monitoring signal, an output voltage monitoring signal, and an input current monitoring signal and controls the on / off of the transistor.

[0031] However, in some situations, the power supply device according to the related art described above may not be able to correctly detect the AC voltage (input voltage) to the power factor correction circuit, which may cause the operation of the power supply device to become unstable.

[0032] In contrast to this, this embodiment provides a power supply device 3 and an image processing device 10 that can easily stabilize their operations using the configuration described below.

[0033] [2] Power supply configuration Next, the configuration of the power supply device 3 according to this embodiment will be described with reference to Fig. 3. Fig. 3 is a block diagram that schematically shows the configuration of the power supply device 3. In this embodiment, the image processing device 10 is an example of an electrical device that receives power from the power supply device 3.

[0034] As shown in FIG. 3, the power supply device 3 includes a first voltage conversion unit 31, a second voltage conversion unit 32, a power factor correction (PFC) circuit 33, an output control unit 34, a stop control unit 35, and a power storage unit C1.

[0035] The power factor correction circuit 33 rectifies the AC voltage and outputs the DC voltage as a predetermined primary voltage Vp1. The power factor correction circuit 33 includes an AC / DC converter and converts the AC voltage of 100V (or 200V) applied from the AC power source AC1 into a primary voltage Vp1 of a desired magnitude, such as DC 450V, and outputs it. The power factor correction circuit 33 has the function of bringing the power factor closer to "1.0" or reducing harmonic components.

[0036] The power storage unit C1 is made up of a capacitor. The power storage unit C1 is connected to the output of the power factor correction circuit 33 and stores the output of the power factor correction circuit 33. In other words, the power storage unit C1 is charged by the primary voltage Vp1 output from the power factor correction circuit 33.

[0037] Both first voltage conversion unit 31 and second voltage conversion unit 32 are switching-type power supply circuits that convert primary voltage Vp1 output from power factor correction circuit 33 into, for example, a DC voltage of a desired magnitude and output it. That is, both first voltage conversion unit 31 and second voltage conversion unit 32 operate using the voltage across power storage unit C1 as input.

[0038] The first voltage conversion unit 31 converts the primary voltage Vp1 into a first DC voltage Vo1 and outputs it. In this embodiment, the first voltage conversion unit 31 generates a voltage of DC 3.3 V (or 5 V) as the first DC voltage Vo1 and outputs the first DC voltage Vo1 to a "first load" such as the main body control unit 16.

[0039] The second voltage conversion unit 32 converts the primary voltage Vp1 into a second DC voltage Vo2 and outputs it. In this embodiment, the second voltage conversion unit 32 generates a voltage of 24 V DC as the second DC voltage Vo2 and outputs the second DC voltage Vo2 to a "second load" such as the ADF 11, the image reading unit 12, and the image forming unit 13.

[0040] The output control unit 34 controls the operation of the first voltage conversion unit 31 and the second voltage conversion unit 32. In the present embodiment, the output control unit 34 receives, for example, a control signal Si1 from the main body control unit 16 as input, and controls the operation of the first voltage conversion unit 31 and the second voltage conversion unit 32 in accordance with the control signal Si1. Here, in the energy saving mode, sleep is input to the output control unit 34 from the main body control unit 16 as the control signal Si1, and the output control unit 34 operates only the first voltage conversion unit 31 of the first voltage conversion unit 31 and the second voltage conversion unit 32.

[0041] As a result, in the normal mode, the output control unit 34 operates both the first voltage conversion unit 31 and the second voltage conversion unit 32, and the power supply device 3 outputs a first DC voltage Vo1 to a "first load" such as the main body control unit 16, and outputs a second DC voltage Vo2 to a "second load" such as the ADF 11. On the other hand, in the energy saving mode, the output control unit 34 stops the second voltage conversion unit 32 while continuing to operate the first voltage conversion unit 31, and the power supply device 3 outputs the first DC voltage Vo1 to the "first load" and stops outputting the second DC voltage Vo2 to the "second load." In other words, the first voltage conversion unit 31 always outputs the first DC voltage Vo1 while the power supply device 3 is operating, whereas the second voltage conversion unit 32 can switch whether or not to output the second DC voltage Vo2 even while the power supply device 3 is operating.

[0042] In this embodiment, the power factor correction circuit 33 enables the power factor correction function only while the second voltage conversion unit 32 is operating, that is, while the second DC voltage Vo2 is being output. In other words, the power factor correction function of the power factor correction circuit 33 is enabled in the normal mode, and disabled in the energy saving mode.

[0043] The stop control unit 35 stops the output of the first voltage conversion unit 31 and the second voltage conversion unit 32 based on the magnitude of the AC voltage Vs1. Specifically, the stop control unit 35 monitors the magnitude (amplitude) of the AC voltage Vs1 input from the AC power supply AC1 to the power factor correction circuit 33, and when the magnitude of the AC voltage Vs1 falls below a threshold and is determined to be an "input low voltage," the stop control unit 35 stops the operation of the first voltage conversion unit 31 and the second voltage conversion unit 32. As a result, when the magnitude of the AC voltage Vs1 falls below the threshold and is an input low voltage, the output of both the first DC voltage Vo1 and the second DC voltage Vo2 is stopped.

[0044] Particularly in this embodiment, the stop control unit 35 detects the magnitude of the AC voltage Vs1 input to the power factor correction circuit 33 using only one of the L (live) and N (neutral) poles of the AC power supply AC1. More specifically, the stop control unit 35 determines the magnitude of the AC voltage Vs1 using only the voltage of the L pole, which is the ungrounded side of the L pole and N pole of the AC power supply AC1. That is, the stop control unit 35 stops the output of the first voltage conversion unit 31 and the second voltage conversion unit 32 based on the magnitude of the AC voltage Vs1 at one of the N pole and the L pole of the AC power supply. This allows the configuration of the stop control unit 35 to be simplified.

[0045] In the power supply device 3 configured as described above, under certain circumstances, the AC voltage Vs1 (input voltage) to the power factor correction circuit 33 may not be detected correctly, which may cause the operation of the power supply device 3 to become unstable. The "certain circumstances" referred to here include, for example, a situation in which the L pole and N pole of an AC plug are connected to the AC power supply AC1 in reverse and the AC power supply AC1 is turned off and on in a short period of time that does not allow the power storage unit C1 to fully discharge. In this case, the magnitude (amplitude) of the detected AC voltage Vs1 decreases and falls below the threshold, so the stop control unit 35 erroneously determines that the input voltage is low and stops output of both the first DC voltage Vo1 and the second DC voltage Vo2, resulting in a startup failure of the power supply device 3.

[0046] Therefore, the power supply device 3 further includes a discharge circuit 36 ​​in addition to the first voltage conversion unit 31, the second voltage conversion unit 32, the power factor correction circuit 33, the output control unit 34, the stop control unit 35 and the power storage unit C1.

[0047] The discharge circuit 36 ​​discharges the power storage unit C1, which is charged by the primary voltage Vp1, thereby reducing the primary voltage Vp1. In other words, the discharge circuit 36 ​​forms a discharge path for discharging the charge stored in the power storage unit C1, thereby promoting a reduction in the voltage across the power storage unit C1. By providing such a discharge circuit 36, the "specific situation" described above becomes less likely to occur, and as a result, startup failures of the power supply device 3 are suppressed, making it possible to realize a power supply device 3 and an image processing device 10 that are more likely to operate stably.

[0048] Here, discharge circuit 36 ​​discharges power storage unit C1 only during a discharge period that satisfies a predetermined condition. That is, discharge circuit 36 ​​does not discharge power storage unit C1 all the time, but discharges power storage unit C1 only during the discharge period. This makes it possible to prevent changes in the characteristics (behavior) of power supply device 3 due to the provision of discharge circuit 36 ​​outside the discharge period.

[0049] The predetermined condition includes a period during which the first DC voltage Vo1 is being output and a specific period based on the timing of switching second voltage conversion unit 32 from an operating state to a stopped state. In other words, if a specific period occurs during which second voltage conversion unit 32 is stopped while first voltage conversion unit 31 continues to operate, such as when switching from the normal mode to the energy-saving mode, the predetermined condition is satisfied, and discharge circuit 36 ​​discharges power storage unit C1. In this way, by actively discharging power storage unit C1 when second voltage conversion unit 32 is stopped, primary voltage Vp1 can be quickly reduced even if almost no power is consumed by the first load after second voltage conversion unit 32 is stopped.

[0050] [3] Examples of power supply devices Next, a specific example of the power supply device 3 will be described with reference to Figures 4 and 5. Figure 5 is a schematic circuit diagram showing an example of the configuration of the output control section .

[0051] The power supply device 3 has a pair of input terminals TN and TL that are connected to an AC plug. The input terminal TN is an input terminal that is connected to the N pole of the AC power supply AC1, and the input terminal TL is an input terminal that is connected to the L pole of the AC power supply AC1.

[0052] The power factor correction circuit 33 has diodes D1 to D4 that form a diode bridge. The first voltage conversion unit 31 has a first switch circuit SW1, and generates a first DC voltage Vo1 by controlling the first switch circuit SW1. The second voltage conversion unit 32 has a second switch circuit SW2, and generates a second DC voltage Vo2 by controlling the second switch circuit SW2.

[0053] Here, the first switch circuit SW1 operates by receiving power from the constant voltage source Vcc0. On the other hand, the second switch circuit SW2 operates by receiving power from the constant voltage source Vcc1. Therefore, when the constant voltage source Vcc1 is stopped, the second switch circuit SW2 is forcibly stopped, and the second voltage conversion unit 32 stops outputting the second DC voltage Vo2.

[0054] The second voltage conversion unit 32 has a capacitor C2 inserted between the reference potential point on the primary side and the ground point on the secondary side. That is, as shown in Fig. 4, the second voltage conversion unit 32 has the capacitor C2 as a bridging capacitor between the low potential point (reference potential point) on the primary side and the low potential point (ground point) on the secondary side.

[0055] Discharge circuit 36 ​​has a discharge resistor R1 and a switch element Q1, and discharges power storage unit C1 by turning on switch element Q1 to connect discharge resistor R1 to a capacitor serving as power storage unit C1.

[0056] 5, the output control unit 34 has a configuration for switching between the normal mode and the energy-saving mode, which is configured to turn the constant voltage source Vcc1 on / off in response to a control signal Si1. That is, when the control signal Si1 is at H (High) level, the constant voltage source Vcc1 is turned on, and when the control signal Si1 is at L (Low) level, the constant voltage source Vcc1 is turned off. Therefore, when the control signal Si1 is at L level (energy-saving mode), the second switch circuit SW2 is forcibly stopped, and the second voltage conversion unit 32 stops outputting the second DC voltage Vo2.

[0057] In the power supply device 3 configured as described above, if the discharge circuit 36 ​​does not operate, a startup failure may occur due to the following mechanism.

[0058] First, when AC power supply AC1 is turned off and on in a short period of time, a state occurs in which primary voltage Vp1 is higher (larger) than AC voltage Vs1. In this state, diodes D1, D2, D3, and D5 do not turn on, and only diode D4 turns on, so there is no discharge path for capacitor C2 and charge accumulates in capacitor C2.

[0059] Then, due to the influence of the voltage across the capacitor C2, the amplitude of the AC voltage Vs1 applied to the L-pole input terminal TN decreases, causing the stop control unit 35 to erroneously determine that the input voltage is low. As a result, the stop control unit 35 forcibly stops the first switch circuit SW1 and the second switch circuit SW2, stopping the output of the first DC voltage Vo1 and the second DC voltage Vo2, resulting in a startup failure.

[0060] In contrast, the power supply device 3 according to this embodiment can prevent the occurrence of startup failures as described above by operating the discharge circuit .

[0061] That is, as shown in Fig. 6, when switching from the normal mode to the energy saving mode, the state (STATE) of the power supply device 3 changes in the order of "1," "2," and "3" shown in Fig. 6. Here, the duration of the state "2" is determined by the time constant of a CR circuit consisting of a resistor R2 (see Fig. 5) and a capacitor C3 (see Fig. 5) provided at the input stage of the control signal Si1 in the output control unit 34.

[0062] When the control signal Si1 switches from H level to L level and the state of the power supply device 3 transitions from "1" to "2," the control signal Si1 is at L level and the constant voltage source Vcc1 is at H level (i.e., operating). In this state "2," the discharge circuit 36 ​​turns on the switch element Q1 to turn on the discharge resistor R1 and discharge the power storage unit C1. When the state of the power supply device 3 transitions from "2" to "3," the constant voltage source Vcc1 transitions to L level (i.e., stopped), and the discharge circuit 36 ​​turns off the switch element Q1 to turn off the discharge resistor R1 and stop the discharge of the power storage unit C1.

[0063] In other words, only during the period of state "2" when switching from the normal mode to the energy saving mode, discharge circuit 36 ​​turns on discharge resistor R1 to discharge power storage unit C1 and quickly lowers primary voltage Vp1. As a result, primary voltage Vp1 quickly drops to AC voltage Vs1, preventing the above-mentioned initial failure mechanism from occurring, where "primary voltage Vp1 is higher (greater) than AC voltage Vs1." Therefore, the occurrence of initial failure is prevented.

[0064] [4] Variation The multiple components included in the power supply device 3 may be provided in multiple housings in a distributed manner. For example, the discharge circuit 36 ​​may be provided separately.

[0065] 4 and 5, the specific configuration of power supply device 3 is not limited to the configuration shown in Fig. 4 and 5, and can be modified as appropriate as long as the same functions can be realized. For example, discharge circuit 36 ​​is not limited to discharge resistor R1, and may be configured to discharge power storage unit C1 using a capacitor, a light-emitting element, or any other electrical load.

[0066] [Appendix to the invention] The following is a summary of the invention extracted from the above-described embodiment. Note that the configurations and processing functions described in the following supplementary notes can be selected and combined as desired.

[0067] <Appendix 1> a power factor correction circuit that rectifies an AC voltage and outputs a DC voltage as a predetermined primary voltage; a first voltage conversion unit that converts the primary voltage into a first DC voltage and outputs the first DC voltage; a second voltage conversion unit that converts the primary voltage into a second DC voltage and outputs the second DC voltage; a stop control unit that stops the outputs of the first voltage conversion unit and the second voltage conversion unit based on the magnitude of the AC voltage; a discharge circuit that discharges a power storage unit that is charged by the primary voltage and reduces the primary voltage. power supply.

[0068] <Appendix 2> the stop control unit stops the outputs of the first voltage conversion unit and the second voltage conversion unit based on the magnitude of the AC voltage at one of the N pole and the L pole of the AC power supply. 1. The power supply device of claim 1.

[0069] <Appendix 3> The second voltage conversion unit has a capacitor inserted between a reference potential point on the primary side and a ground point on the secondary side. 3. The power supply device of claim 1 or 2.

[0070] <Appendix 4> the discharge circuit discharges the power storage unit only during a discharge period that satisfies a predetermined condition. 4. The power supply device according to any one of Supplementary Notes 1 to 3.

[0071] <Appendix 5> the predetermined condition includes a specific period during which the first DC voltage is being output and based on a timing of switching the second voltage conversion unit from an operating state to a stopped state. 10. The power supply device of claim 4.

[0072] <Appendix 6> A power supply device according to any one of Supplementary Notes 1 to 5; a main body having an image processing function; Image processing device. [Explanation of symbols]

[0073] 1 Main unit 3 Power supply 10 Image processing device 31 First voltage conversion unit 32 Second voltage conversion unit 33 Power factor correction circuit 35 Stop control section 36 Discharge circuit C1 power storage unit C2 capacitor Vo1 First DC voltage Vo2 Second DC voltage Vp1 Primary voltage Vs1 AC voltage

Claims

1. a power factor correction circuit that rectifies an AC voltage and outputs a DC voltage as a predetermined primary voltage; a first voltage conversion unit that converts the primary voltage into a first DC voltage and outputs the first DC voltage; a second voltage conversion unit that converts the primary voltage into a second DC voltage and outputs the second DC voltage; a stop control unit that stops the outputs of the first voltage conversion unit and the second voltage conversion unit based on the magnitude of the AC voltage; a discharge circuit that discharges a power storage unit that is charged by the primary voltage and reduces the primary voltage. power supply.

2. the stop control unit stops the outputs of the first voltage conversion unit and the second voltage conversion unit based on the magnitude of the AC voltage at one of the N pole and the L pole of the AC power supply. The power supply device of claim 1 .

3. the second voltage conversion unit has a capacitor inserted between a reference potential point on the primary side and a ground point on the secondary side; 3. The power supply device according to claim 1 or 2.

4. the discharge circuit discharges the power storage unit only during a discharge period that satisfies a predetermined condition.

3. The power supply device according to claim 1 or 2.

5. the predetermined condition includes a specific period during which the first DC voltage is being output and based on a timing of switching the second voltage conversion unit from an operating state to a stopped state.

5. The power supply device according to claim 4.

6. The power supply device according to claim 1 or 2; a main body having an image processing function; Image processing device.

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