JP2010049183A - Electronic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic apparatus that reliably applies a DC voltage required for the component, while configuring a DC power supply circuit for supplying power to a component required for severe supply of power at a low cost. <P>SOLUTION: The electronic apparatus 1 includes: a first DC power supply circuit 29 that generates a first DC voltage from an AC power supply 27; a first power supply path 26 that supplies power to a first load group, which can be added to the first DC power supply circuit 29; a second DC power supply circuit 28 that generates a second DC voltage higher than the first DC voltage, from the AC power supply 27; and a second power supply path 25 that supplies power to a second load group from the second DC power supply circuit 28. The electronic apparatus 1 is configured so that a third DC power supply circuit 45 can be added which is used to generate the first DC voltage by the supply of power from the second DC power supply circuit 28. The electronic apparatus 1 is provided with a third power supply path 46 that supplies power to part of the first load group from the third DC power supply circuit 45. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention includes a first DC power supply circuit that generates a first DC voltage from an AC power supply, a first power supply path that supplies power to a first load group that can be expanded from the first DC power supply circuit, and the AC power supply. To an electronic device including a second DC power supply circuit that generates a second DC voltage higher than the first DC voltage, and a second power supply path that supplies power to the second load group from the second DC power supply circuit.

  2. Description of the Related Art An image forming apparatus such as a so-called multifunction machine having a plurality of functions in one unit is configured by adding an optional unit for executing a function desired to be added to a main body that performs image formation. For example, the optional unit includes a paper feed unit that feeds a large amount of paper and different types of paper, a paper discharge unit that performs post-processing such as stapling, punching, and sorting, and a document reading unit that reads a document image and generates image data There are a document transport unit that automatically transports a document placed on a document placement unit to a document reading unit, a data storage unit that stores image data so that it can be reused, and the like.

  An image forming apparatus that is an electronic device includes components such as a CPU, an ASIC, and a sensor, and components such as a drive motor, a hard disk, and a backlight of a liquid crystal panel. Since the voltage required for driving differs between the former part and the latter part, the image forming apparatus includes a first DC power supply circuit that generates a first DC voltage to be supplied from the AC power source to the former part and a first DC power supply that supplies power to the latter part. A power supply device including a second DC power supply circuit that generates a second DC voltage higher than one DC voltage from an AC power supply is connected.

For example, Patent Document 1 discloses that a power source that generates 24 V required for a main unit drive circuit that drives a main unit and a double-side unit drive circuit that drives a double-sided unit and 5 V required for a circuit such as logic is provided inside the main unit. Discloses a laser beam printer.
JP-A-8-101607

  A voltage range that guarantees normal operation is set for a component to which a DC voltage is supplied from the power supply device, and the power supply device is designed to supply a DC voltage within the voltage range. In particular, a severe voltage range is set for precision components such as CPU and ASIC, which are the former components, and the first DC power supply circuit is designed so that a DC voltage can be supplied within the severe voltage range. The

  However, the direct-current voltage supplied to each component by the power supply device fluctuates due to a voltage drop caused by an increase in the load due to the addition of the unit or an increase in the resistance of the power supply path. Therefore, the first DC power supply circuit needs to be designed in consideration of a voltage drop when an additional unit can be added to the main body.

  However, if the first DC power supply circuit is designed assuming a voltage drop when all the units that can be added to the main unit are added, it is rare to add all the units, so there is a possibility that it will be overspec. High and unnecessary costs increase. In addition, since the voltage drop can also be caused by voltage fluctuations of the AC power supply, in addition to the voltage drop when all the expandable units are added, the first DC Designing the power supply circuit will further increase the cost.

  In view of the above problems, an object of the present invention is to provide an electronic device that can reliably supply a DC voltage necessary for a component while configuring a DC power supply circuit that supplies the component that requires severe power supply at a low cost. The point is to provide.

  In order to achieve the above-mentioned object, a first characteristic configuration of an electronic apparatus according to the present invention is a first direct current generating a first DC voltage from an AC power source as described in claim 1 of the claims. A first power supply path that supplies power to the first load group that can be added from the first DC power supply circuit, and a second DC voltage that is higher than the first DC voltage from the AC power supply. An electronic apparatus comprising a DC power supply circuit and a second power supply path for supplying power to the second load group from the second DC power supply circuit, wherein the first DC voltage is generated by power supply from the second DC power supply circuit The third DC power supply circuit is configured such that it can be added, and a third power supply path for supplying power from the third DC power supply circuit to a part of the first load group is provided.

  By adding the third DC power supply circuit, the voltage drop generated in the first DC voltage supplied from the first DC power supply circuit is improved by adding the first load group, and the necessary DC voltage is supplied to the first load group. The possibility that power can be supplied is increased.

  As described in claim 2, the second characteristic configuration includes a current suppression circuit that suppresses the outflow of current from the third power supply path to the first power supply path in addition to the first characteristic structure described above. It is in the point to have.

  According to the above-described configuration, a part of the first load group may be damaged due to a current from the third power supply path that wraps around a part of the first load group that supplies power from the first power supply path. Occurrence can be prevented.

  In the third feature configuration, as described in claim 3, in addition to the first or second feature configuration described above, a part of the first load group is output from the first DC power supply circuit. A voltage monitoring unit is provided for monitoring the first DC voltage to be notified and prompting the expansion of the third DC power supply circuit when the first DC voltage falls below an allowable voltage. is there.

  Since the normal operation of the first load group may become unstable if the first DC voltage falls below the allowable voltage that is the lower limit voltage that guarantees the normal operation of the first load group, the third DC power supply circuit Additional expansion is required. According to the above-described configuration, it is possible to easily determine whether or not the third DC power supply circuit needs to be added based on the notification from the voltage monitoring unit, and it is possible to prevent the overspec and suppress the cost.

  In the fourth feature configuration, as described in claim 4, in addition to the third feature configuration described above, the voltage monitoring unit monitors the connection state of the first load group and adds the first feature configuration. The point is to notify that the characteristic of the third DC power supply circuit to be added can be determined based on the current capacity of the load group.

  By adding an appropriate third DC power supply circuit based on the notification from the voltage monitoring unit, it is possible to reliably supply the first load group with a DC voltage that is higher than the allowable voltage required for normal operation of the first load group. .

  In the fifth characteristic configuration, as described in claim 5, in addition to the fourth characteristic configuration described above, the voltage monitoring unit is configured to be able to input the characteristics of an additional third DC power supply circuit, The point is that the compatibility of the added third DC power supply circuit is judged and the result is notified.

  When a third DC power supply circuit that is not originally a third DC power supply circuit to be added is mistakenly added, the error can be easily recognized.

  In the sixth feature configuration, in addition to any one of the first to fifth feature configurations described above, the first feature in which a housing portion for housing the third DC power supply circuit can be added is provided. It is in the point provided in the load group.

  By providing the accommodating portion, it is easy to add a third DC power supply circuit.

  The characteristic configuration of the image forming apparatus according to the present invention is an image forming apparatus in which an electronic device having any one of the first to sixth characteristic configurations prints an image on paper as described in claim 7 and can be expanded. The first load group includes any of a paper feed unit, a paper discharge unit, a document reading unit, a document transport unit, and a data storage unit.

  An image forming apparatus to which any of a paper feed unit, a paper discharge unit, a document reading unit, a document transport unit, or a data storage unit is added is suitable as an electronic apparatus that employs the present invention.

  As described above, according to the present invention, it is possible to provide an electronic apparatus that can reliably supply a DC voltage necessary for a component while configuring a DC power supply circuit that supplies the component that requires severe power supply at a low cost. It became possible to do.

  Hereinafter, an electronic apparatus adopting the present invention will be described. The electronic device 1 includes a device main body 3, an option unit that can be added to the main body 3, expands the functions of the electronic device 1, and a power supply device 2 that supplies a DC voltage to the main body 3 and the option unit. As shown in FIG. 1, two optional units (first unit 4 and second unit 5) are added to the main body 3 of the electronic device 1.

  The main body 3, the first unit 4, and the second unit 5 include a first load 30, 40, 50 (hereinafter also referred to as a “first load group”) to which a first DC voltage is fed, and a first straight line. Second loads 31, 41, 51 (hereinafter also referred to as “second load group”) to which a second DC voltage higher than the current voltage is fed, and the first loads 30, 40, 50 and the second loads, respectively. Control units 33, 43, 53 for controlling 31, 41, 51 are provided.

  The system control unit 33, the first unit control unit 43, and the second unit control unit 53 include a CPU, a ROM that stores an operation program executed by the CPU, a RAM that is a work area of the CPU, and peripheral circuits. The system control unit 33, the first unit control unit 43, and the second unit control unit 53 are connected to each other by a signal line.

  The system control unit 33, the first unit control unit 43, and the second unit control unit 53 reduce the first DC voltage supplied from the first power supply path 26 to a predetermined voltage by the step-down circuits 32, 42, and 52. Drive with. That is, the system control unit 33, the first unit control unit 43, and the second unit control unit 53 cooperate with the step-down circuits 32, 42, 52 to supply the first power as a part of the first loads 30, 40, 50. Power is supplied from the path 26.

  The power supply device 2 includes a first DC power supply circuit 29 that generates a first DC voltage from the AC power supply 27 and a second DC power supply circuit 28 that generates a second DC voltage from the AC power supply 27.

  The main body 3, the first unit 4, the second unit 5, and the power supply device 2 are connected to a power feeding path via a connector (not shown). With this connection, the electronic device 1 has a first power supply path 26 that supplies power from the first DC power supply circuit 29 to the first load group, and a second power supply path 25 that supplies power from the second DC power supply circuit 28 to the second load group. Is formed.

  As described above, the electronic device 1 supplies power to the first DC power supply circuit 29 that generates the first DC voltage from the AC power supply 27 and the first load group that can be expanded from the first DC power supply circuit 29. A power supply path 26, a second DC power supply circuit 28 that generates a second DC voltage higher than the first DC voltage from the AC power supply 27, and a second power supply path 25 that supplies power from the second DC power supply circuit 28 to the second load group. It has.

  The system control unit 33 directly controls the first load 30 and the second load 31, and also controls the first loads 40 and 50 and the second loads 41 and 51 via the first and second unit control units 43 and 53. To control the electronic device 1 as a whole.

  By the way, a voltage drop occurs in the first DC voltage fed from the first feeding path 26 to the first load group due to the current capacity of the first loads 40 and 50 and the resistance of the first feeding path 26 and the connector. If the first DC voltage drops below the allowable voltage (the lower limit voltage of the voltage that guarantees the normal operation of the first load group) due to the voltage drop, the operation of the first load group may become unstable.

  Therefore, the electronic device 1 has an additional third DC power supply circuit that generates the first DC voltage by power supply from the second DC power supply circuit 28 so that the first DC voltage does not drop below the allowable voltage. A third power supply path that supplies power to a part of the first load group from the third DC power supply circuit is provided. This will be described in detail below.

  The electronic device 1 is provided with a first load group in which a housing unit that houses the third DC power supply circuit can be added. In the present embodiment, the first unit 4 is provided with the accommodating portion. The third DC power supply circuit includes a regulator, and is configured to generate and output a first DC voltage from the second DC voltage with the regulator.

  Accordingly, by accommodating the third DC power supply circuit 45 in the accommodating portion, the first DC voltage generated by the third DC power supply circuit 45 is part of the first load group via the third power supply path 46. A certain first load 40 can be supplied with power.

  Since the first power supply path 26 and the third power supply path 46 are both connected to the first load 40, the first power supply path 26 and the third power supply path 46 are electrically connected. Therefore, a diode 44 is provided in the connection line between the first power supply path 26 and the third power supply path 46 as a current suppression circuit that suppresses the outflow of current from the third power supply path 46 to the first power supply path 26. The anode of the diode 44 is connected to the first power supply path 26 side, and the cathode is connected to the third power supply path 46 side.

  As described above, the first load group includes the system control unit 33, the first unit control unit 43, and the second unit control unit 53. In particular, the power supply characteristics of the first load group at the start are severe. However, the provision of the diode 44 effectively prevents damage due to current sneaking into the first load group.

  The system control unit 33 monitors the first DC voltage output from the first DC power supply circuit 29, and adds the third DC power supply circuit 45 when the first DC voltage falls below the allowable voltage. A power supply monitoring unit 37 is provided for informing so as to prompt. The power supply monitoring unit 37 is a functional block embodied in the system control unit 33 by executing an operation program stored in the ROM by the CPU of the system control unit 33.

  The main body 3 includes a monitor voltage generation circuit 39 that generates a monitoring voltage obtained by stepping down the first DC voltage to a predetermined voltage, and a reference voltage that generates a reference voltage for monitoring the first DC voltage from the second DC voltage. A generation circuit 38 is provided. The reference voltage is set based on the allowable voltage of the first DC voltage.

  The monitor voltage generation circuit 39 divides the first DC voltage by the two resistance elements and inputs it to the AD port of the system control unit 33. The reference voltage generation circuit 38 is configured by, for example, a dropper type regulator, generates a stable reference voltage from the second DC voltage, and inputs it to the AD port of the system control unit 33.

  The power supply monitoring unit 37 AD-converts the reference voltage input from the reference voltage generation circuit 38 and the monitor voltage generation circuit 39 and the monitor voltage, and compares the values. When the monitoring voltage is lower than the reference voltage, it is determined that the first DC voltage is lower than the allowable voltage. For example, via a liquid crystal display unit of an operation unit (not shown) provided in the main body 3 or the like. Then, a notification is made so as to encourage the addition of the third DC power supply circuit 45.

  Here, the power supply monitoring unit 37 monitors the connection state of the first load group so that the characteristics of the third DC power supply circuit 45 to be added can be determined based on the current capacity of the added first load group. It is comprised so that it may alert | report. This will be described in detail below.

  The ROM provided in the system control unit 33 includes a first load provided in a unit connectable to the main body 3 (including units connectable to the main body 3 other than the first unit 4 and the second unit 5). Current capacity table data in which the current capacity is stored and characteristics of each third DC power supply circuit 45 that can be accommodated in the accommodating portion of the first unit 4 (for example, each current capacity, each switching regulator, series regulator, etc. The third DC power supply circuit table data storing the model etc. is stored.

  The power supply monitoring unit 37 communicates with the first and second unit control units 43 and 53 to classify the first loads 40 and 50 (the type indicates what kind of component the first load is). For example, CPU, ASIC, sensor, etc. are shown) and connection load information such as current capacity is acquired, and the connection state of the added first load group is monitored.

  The power monitoring unit 37 refers to the current capacity table data and calculates the current capacity of the first load group (first loads 40 and 50 in the present embodiment) added based on the connection load information. Referring to the third DC power supply circuit table data, a third that can secure at least the current capacity of the first load (first load 40 in the present embodiment) fed from the third DC power supply circuit 45 accommodated in the first unit 4. The DC power supply circuit 45 is selected based on the current capacity. Notification is made so that the characteristics of the selected third DC power supply circuit 45 can be discriminated.

  Further, the voltage monitoring unit 37 is configured so that the characteristics of the added third DC power supply circuit 45 can be input in order to prevent the third DC power supply circuit 45 from being erroneously accommodated. It is configured to determine suitability and notify the result. This will be described in detail below.

  As shown in FIG. 2, the third DC power supply circuit 45 includes a characteristic data output unit 451. The characteristic data output unit 451 inputs a bit signal indicating the characteristic of the regulator 450 of the third DC power supply circuit 45 provided therein to the input ports P0 to P2 of the system control unit 33 via the bit signal line.

  The first DC voltage generated by the regulator 450 is input to the bit signal line, and the bit signal is generated by turning on or off the bit signal line. In FIG. 2, a bit signal “011” is input to the system control unit 33. In this embodiment, the characteristic data output unit 451 is configured to output a 3-bit bit signal. However, the number of bits of the bit signal depends on the characteristics of the third DC power supply circuit 45 that can be added. Needless to say, it may be changed as appropriate.

  The third DC power supply circuit table data stores a bit signal corresponding to each third DC power supply circuit 45 that can be added to an optional unit connectable to the main body 3.

  Based on the bit signal input from the characteristic data output unit 451, the power supply monitoring unit 37 grasps the characteristics of the third DC power supply circuit 45 accommodated in the accommodating unit of the first unit 4 and increases the third DC It is determined whether or not the power supply circuit 45 is compatible with the third DC power supply circuit 45 that should be added, and the result of the determination is notified. When the result of determination is met, the fact that it is compatible is notified, and when the result of determination is not met, the third DC power supply circuit 45 is erroneously added, and the correct third DC power supply circuit 45 is connected. Notify that it should be replaced.

  The operation of the voltage monitoring unit 37 will be described using the flowchart shown in FIG.

  The voltage monitoring unit 37 communicates with the first and second unit control units 43 and 53, monitors the connection state of the added first load group, and calculates the current capacity of the first load group (S1). Further, the first DC voltage is monitored, and when the first DC voltage falls below the allowable voltage (S2), the third DC to be added based on the current capacity of the first load group calculated in the monitoring in step 1 The power supply circuit 45 is selected, a notification is given so that the characteristics of the selected third DC power supply circuit 45 can be determined, and an extension of the third DC power supply circuit 45 is requested (S3).

  Based on the bit signal indicating its own characteristics input from the third DC power supply circuit 45 that is accommodated and expanded in the accommodation unit, the voltage monitoring unit 37 determines the suitability of the additional third DC power supply circuit 45. (S4).

  When the voltage monitoring unit 37 determines that it is compatible (S5), it notifies that it is compatible (S6), and when it determines that it is not compatible (S5), the expanded third DC power supply circuit 45 should be originally added. The fact that it is recommended to replace the third DC power supply circuit 45 is notified (S7).

  Hereinafter, an embodiment in which an image forming apparatus that prints an image on a sheet is the electronic apparatus of the present invention will be described.

  As shown in FIG. 4, the image forming apparatus 10 includes a main body 8 that forms an image on paper by an electrophotographic method, an optional unit that can be added to the main body 8, and a power supply device that supplies a DC voltage to the main body 8 and the optional unit. 9 is provided. Optional units that can be added to the main body 8 include a paper feed unit, a paper discharge unit, a document reading unit, a document transport unit, a data storage unit, and the like.

  As shown in FIG. 4, the image forming apparatus 10 according to the present embodiment has a document reading unit 6 and a sheet feeding unit 7 added to a main body 8, but an optional unit including any of the above-described optional units is installed in the main body. The present invention can also be applied to the image forming apparatus 10 added to 8.

  The main body 8 includes an operation unit 86, a print engine (not shown) that forms an image on a sheet, and a system control unit 83 that controls them. The main body 8 includes, as the first load 80, a CPU 84, a step-down circuit 82 that supplies power to the CPU 84, an image processing ASIC 85, and a monitor voltage generation circuit 89 that generates a monitoring voltage obtained by stepping down the first DC voltage to a predetermined voltage. And a sensor for detecting the presence / absence of a sheet, a fixing temperature, and the like. The step-down circuit 82 and step-down circuits 62 and 72 described later are so-called three-terminal regulators.

  As the second load 81, a reference voltage generation circuit 88 that generates a reference voltage for monitoring the first DC voltage from the second DC voltage, a backlight 861 of the liquid crystal panel 860 provided in the operation unit 86, and a print A motor 810 and a clutch 811 for driving a photoconductor and a paper transport roller provided in the engine are provided.

  The CPU 84, the step-down circuit 82, the image processing ASIC 85, the monitor voltage generation circuit 89, and the reference voltage generation circuit 88 are arranged on the substrate and constitute a system control unit 83. The system control unit 83 includes a voltage monitoring unit 87.

  The paper feed unit 7 includes a plurality of paper feed cassettes (not shown), a paper feed roller (not shown) for feeding paper from each paper feed cassette, and a paper feed controller 73 for controlling the paper feed rollers. Yes. Further, the paper feed unit 7 includes a housing portion that houses the third DC power supply circuit 75. A third power supply path 76 for supplying the first DC voltage to the first load 70 from the third DC power supply circuit 75 accommodated in the accommodating portion is provided.

  The paper feed control unit 73 includes a CPU and a step-down circuit 72 that supplies power to the CPU. The paper feed unit 7 includes a sensor 700 that detects the presence or absence of paper as a first load 70 and a paper feed controller 73, and a motor 710 that drives a paper feed roller as a second load 71.

  The document reading unit 6 includes a light source that irradiates the document, a scanner CCD 610 that receives reflected light from the light source and generates image data of the document image, and conveys the document from the document placement unit. A conveyance roller and a conveyance belt for discharging a document whose reading has been completed to a discharge tray, and a reading control unit 63 for controlling them are provided.

  The reading control unit 63 includes a CPU and a step-down circuit 62 that supplies power to the CPU. The document reading unit 6 includes a sensor 600 that detects the presence or absence of paper and a reading control unit 63 as a first load 60, and a motor 611 that drives a conveyance roller and a conveyance belt, and a scanner CCD 610 as a second load 61. .

  The power supply device 9 includes a first DC power supply circuit 99 that generates a first DC voltage from the AC power supply 97, and a second DC power supply circuit 98 that generates a second DC voltage higher than the first DC voltage from the AC power supply 97. It has. As shown in FIG. 5, the first DC power supply circuit 99 and the second DC power supply circuit 98 include a transformer that receives AC100V from the AC power supply 97 on the primary side and outputs AC12V and AC26V on the secondary side, A rectifier circuit that rectifies the output and a regulator that outputs AC5V and AC12V are provided.

  Further, a paper feeding unit 7 and a document reading unit 6 are added to the main body 8, and a first DC voltage and a second DC voltage are supplied from the power supply device 9 to the main body 8, the paper feeding unit 7 and the document reading unit 6. One power supply path 96 and a second power supply path 95 are formed. The power supply path from the first power supply path 96 to the first load 70 is provided with a diode 74 as a current suppression circuit that suppresses the outflow of current from the third power supply path 76 to the first power supply path 96.

  The power supply monitoring unit 87 recognizes that the option units added to the main body 8 are the document reading unit 6 and the sheet feeding unit 7 through communication with the reading control unit 63 and the sheet feeding control unit 73, and is provided respectively. The current capacity of the first load group which is the first loads 60 and 70 is calculated.

  When the monitor voltage input from the monitor voltage generation circuit 89 is lower than the reference voltage input from the reference voltage generation circuit 88, it is determined that the first DC voltage has decreased below the allowable voltage.

  When the power monitoring unit 87 determines that the first DC voltage has decreased below the allowable voltage, the power monitoring unit 87 can determine the characteristics of the third DC power circuit 75 to be added based on the calculated current capacity of the first load group. Is notified to the operation unit 86 to prompt the extension of the third DC power supply circuit 75.

  In addition, the power supply monitoring unit 87 determines the suitability of the third DC power supply circuit 75 based on the characteristics of the third DC power supply circuit 75 after the third DC power supply circuit 75 is accommodated and expanded in the storage unit. Then, the result is notified.

  Hereinafter, another embodiment will be described.

  In the above-described embodiment, it has been described that one of the two optional units to be added to the main unit is configured to be able to add the third DC power supply circuit. The accommodation unit may be provided in the option unit.

  With reference to FIGS. 6A to 6D, an explanation will be given regarding the addition of the third DC power supply circuit when the optional unit configured to be able to add the third DC power supply circuit is added to the main body. In FIGS. 6A to 6D, the first DC voltage is represented as “V1” and the second DC voltage is represented as “V2”.

  FIG. 6A shows an electronic device in which only a unit A having a small current capacity is added to a main body to which a power supply device is connected. In the electronic device, the addition of the unit A does not cause the first DC voltage to fall below the allowable voltage, and no notification is made by the power supply monitoring unit. There is no need to add a third DC power supply circuit to the unit A, and the first DC voltage is supplied from the first power supply path to the first load provided in the unit A.

  FIG. 6B shows an electronic device in which a unit B having a small current capacity is added to the power supply device shown in FIG. Since the current capacity of the first load provided in the unit B is small, the first DC voltage does not drop below the allowable voltage even in the electronic device, and no notification is given by the power supply monitoring unit. There is no need to add a third DC power supply circuit to the unit A or the unit B, and the first DC voltage is supplied from the first power supply path to the first loads provided respectively.

  FIG. 6C shows an electronic device in which a unit C having a large current capacity is added to the power supply device shown in FIG. When the current capacity of the first load provided in the unit C is large and the first DC voltage supplied from the first power supply path to the first load group falls below the allowable voltage, the power supply monitoring unit is to be added. Informs the characteristics of the DC power supply circuit and encourages the addition of a third DC power supply circuit.

  When the third DC power supply circuit is added to the unit C based on the notification, the first DC voltage is supplied to the first load of the unit C from the third power supply path. As a result, it is possible to prevent the first DC voltage supplied to the first load group from decreasing to the allowable voltage.

  FIG. 6D shows an electronic device in which a unit C and a unit D having a large current capacity are added to the main body to which the power supply device is connected. When the current capacity of the first load provided in the unit C and the unit D is large and the first DC voltage fed from the first feeding path to the first load group falls below the allowable voltage, the power supply monitoring unit is added. Informs the characteristics of the third DC power supply circuit to encourage the addition of the third DC power supply circuit.

  When the third DC power supply circuit is added to the units C and D based on the notification, the first DC voltage is supplied to the first loads of the units C and D from the respective third power supply paths. As a result, it is possible to prevent the first DC voltage supplied to the first load group from decreasing to the allowable voltage.

  In the above-described embodiment, the current suppression circuit has been described as a diode. However, when the third DC power supply circuit is added without a diode, the current suppression circuit is supplied to the first load fed from the third DC power supply circuit. The power supply path for supplying the first DC voltage from the first power supply path may be cut. In this case, for example, a switch for cutting the power feeding path may be provided, and the power feeding path may be cut by the switch serving as a current suppression circuit. Of the connectors connecting the main body and the option unit, the connector related to the power feeding path may not be connected. At this time, the connector functions as a current suppression circuit. Further, the current suppression circuit may be a so-called current limiter in which the resistance increases as the flowing current increases.

  In the above-described embodiment, the first power supply path has been described as being configured by a single power supply path from the power supply device to the main body and all the optional units. It may be configured by a plurality of power supply paths.

  In the above-described embodiment, the third DC power supply circuit is added to the option unit, but may be configured to be extendable to the main body.

  Each of the above-described embodiments is merely an example of the present invention, and the scope of the present invention is not limited by the description. The specific configuration of each part is appropriately changed within the scope of the effects of the present invention. It goes without saying that it can be done.

Illustration of electronic device Explanatory drawing of characteristic data output unit Flow chart explaining operation of power supply monitoring unit Illustration of the image forming apparatus Illustration of power supply (A) to (d) is an explanatory view of an electronic device in another embodiment

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 10: Electronic device, Image forming apparatus 2, 9: Power supply device 3, 8: Main body 4, 7: First option unit, Paper feed unit 5, 6: Second option unit, Document reading unit 25, 95: First Two power supply paths 26, 96: First power supply path 27, 97: AC power supply 28, 98: Second DC power supply circuit 29, 99: First DC power supply circuit 37, 87: Power supply monitoring unit 44, 74: Current suppression circuit 45, 75: Third DC power supply circuit 46, 76: Third power supply path

Claims (7)

A first DC power supply circuit that generates a first DC voltage from an AC power supply; a first power supply path that supplies power to a first load group that can be expanded from the first DC power supply circuit; An electronic device comprising a second DC power supply circuit that generates a second DC voltage higher than the DC voltage, and a second power supply path that supplies power to the second load group from the second DC power supply circuit,
A third DC power supply circuit that generates the first DC voltage by power supply from the second DC power supply circuit is configured to be expandable, and the third DC power supply circuit supplies power to a part of the first load group. Electronic equipment provided with three feeding paths.   The electronic device according to claim 1, further comprising a current suppression circuit that suppresses an outflow of current from the third power supply path to the first power supply path.   The first DC voltage output from the first DC power supply circuit is monitored on a part of the first load group, and when the first DC voltage falls below an allowable voltage, the third DC The electronic device according to claim 1, further comprising a voltage monitoring unit for informing so as to promote the addition of a power circuit.   The voltage monitoring unit monitors the connection state of the first load group, and notifies that the characteristics of the third DC power supply circuit to be added can be determined based on the current capacity of the added first load group. Item 4. The electronic device according to Item 3.   The electronic device according to claim 4, wherein the voltage monitoring unit is configured to be able to input characteristics of an additional third DC power supply circuit, determines compatibility of the added third DC power supply circuit, and notifies the result. .   The electronic device according to claim 1, wherein a housing portion that houses the third DC power supply circuit is provided in a first load group that can be expanded.   The electronic apparatus according to claim 1 is an image forming apparatus that prints an image on a sheet, and a first load group that can be added includes a paper feed unit, a paper discharge unit, a document reading unit, a document transport unit, An image forming apparatus including any of the data storage units.

Images