JP6225866B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus that supplies power to a device connected to a connector and communicates with the device.

  In some cases, peripheral devices can be connected to a device on the main body side such as an image forming apparatus. Then, the device on the main body side may supply power to the connected peripheral device. As a result, there is no need to connect the peripheral device and the outlet with a power cord, and it is not necessary to provide a battery in the peripheral device, and it is not necessary to prepare a power source on the peripheral device side. One of the standards by which the main body side supplies power to peripheral devices is the USB standard. However, there is a limit to the power (current) that can be supplied to the device, and when a peripheral device is connected, there may be a problem in balance with the limitation of the power supply capability.

  Specifically, Patent Document 1 describes an example of processing when a memory card is connected to a USB interface. Specifically, in Patent Document 1, a memory card reader that operates by supplying power from a Vbus of a USB interface and reads data stored in a memory card is connected to the USB interface, and the memory card reader is connected via the USB interface. Receives the read data, records the received data on paper, monitors the current of Vbus, stops the power supply to Vbus connected to the memory card reader according to the current monitoring signal, and supplies power to Vbus A recording device is described that ignores the current monitoring signal and does not stop the power supply to Vbus for a certain time set in the timer after supplying. With this configuration, when the inrush current of the memory card is large, it is not determined that an abnormal memory card has been inserted, and the power supply to the memory card is not stopped (Patent Document 1: Claim 1, paragraph [ [0008] etc.).

JP 11-149777 A

  There are various peripheral devices (devices). For example, the USB standard includes a keyboard, a mouse, a USB memory, a hard disk drive, a wireless LAN transceiver (adapter), a camera, a scanner, a card reader, and the like.

  In order to supply power to the device, the power (voltage) generated by the power supply circuit is applied to the device connection connector. Usually, one or more members and elements are passed until the output of the power supply circuit is input to the device. The device is provided with a connector for connecting to the connector of the device on the main body side. In some cases, the connector of the device on the main body side and the connector of the device are connected by a cable. Furthermore, the power supply circuit and the connector board may be connected by a harness. Furthermore, in power saving mode, a switch for turning on / off the power supply is provided between the power supply circuit and the connector of the device on the main unit to cut off the power supply to the connector of the main unit and related circuits. Sometimes.

  As the number of members and elements until the output of the power supply circuit is input to the device increases, the impedance of the entire power supply line (power supply path) from the power supply circuit to the device increases. As the impedance of the entire power supply line increases, a voltage lower than the voltage range (specified voltage range) defined by the standard is more likely to be input to the device due to the voltage drop. In particular, when the current flowing through the device is large, the voltage dropped in the power supply line is large, and the voltage input to the device is small. In the USB standard, the specified voltage range is 4.75 to 5.25V.

  When the voltage input to the device falls below the specified voltage range, the device may malfunction. For example, the operation of the device may become unstable. In addition, malfunction of the device may occur or the device may not operate. Therefore, when power is supplied to a device connected to the connector, there is a problem that a voltage input to the device should not fall below a specified voltage range due to a voltage drop.

  The technique described in Patent Document 1 relates to power supply to a device connected to the device main body. The technique described in Patent Document 1 does not determine that there is a problem even if a large current that exceeds the current value determined by the standard temporarily flows when the memory card is connected due to a large capacitance. It is what you want to do. However, it has nothing to do with the voltage drop due to the use of connectors, cables, harnesses, etc., and the above problem cannot be solved.

  In view of the above-described problems of the prior art, the present invention inputs a voltage having a magnitude within a specified range to a connected device, regardless of which device is connected, while minimizing power consumption.

In order to solve the above problem, an image forming apparatus according to a first aspect includes a connector, a power supply circuit, a processing unit , and a storage unit . The connector is for connecting a device directly or via a cable. The power supply circuit supplies power to a device connected to the connector. The processing unit communicates with a device connected to the connector, recognizes a device connected to the connector, and outputs a first voltage to the power supply circuit when no device is connected to the connector, While the device is connected to the connector, the voltage that is greater than the first voltage and that is input to the device connected to the connector is a voltage within a specified voltage range that is a predetermined voltage range. The second voltage is output to the power supply circuit. The storage unit stores registered device data indicating a registered device registered in advance. The processing unit obtains a device code indicating a device type from the device connected to the connector, recognizes the device connected to the connector based on the device code, and the connected device is the registered device. At some time, the power supply circuit outputs the second voltage, and when the connected device is not the registered device, the power supply circuit outputs the first voltage.

  According to the present invention, no matter what device is connected, a voltage having a magnitude within a specified range can be input to the device. In addition, since the output voltage value of the power supply circuit is dropped to the first voltage when it is not necessary, it is possible to suppress power consumption as compared with the case where the output voltage value of the power supply circuit is always set high.

1 is a diagram illustrating an example of a multifunction machine according to an embodiment. 1 is a block diagram illustrating an example of a configuration of a multifunction machine according to an embodiment. FIG. 5 is a diagram for explaining data communication and power supply with a device of the multifunction peripheral according to the embodiment. It is a flowchart which shows an example of the flow of a change process of the output of the power supply circuit (DCDC converter) which concerns on embodiment. It is a figure which shows an example of the device registration screen which concerns on embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. In the following description, the multifunction peripheral 100 (corresponding to an image forming apparatus) will be described as an example. However, each element such as configuration and arrangement described in this embodiment does not limit the scope of the invention and is merely an illustrative example.

(Outline of image forming apparatus)
Next, an outline of the multifunction peripheral 100 according to the embodiment will be described with reference to FIG. FIG. 1 is a diagram illustrating an example of a multifunction peripheral 100 according to the embodiment.

  As shown in FIG. 1, an operation panel 1 (illustrated with a broken line) is provided on the front surface of the multifunction peripheral 100. In addition, a document transport unit 2a and an image reading unit 2b are provided at the top. In addition, a printing unit 3 (a paper feeding unit 3a, a conveyance unit 3b, an image forming unit 3c, and a fixing unit 3d) that performs printing is provided in the multifunction peripheral 100.

  The operation panel 1 includes a display unit 11 that displays the state of the multifunction peripheral 100, various messages, and various setting screens. A touch panel unit 12 is provided on the upper surface of the display unit 11. The touch panel unit 12 is for recognizing a button or key (soft key) pressed on the display unit 11. The operation panel 1 is also provided with a plurality of hard keys 13 such as a start key and a numeric keypad. The operation panel 1 accepts an input by the user to the touch panel unit 12 and the hard keys 13 as a setting operation.

  The document conveying section 2a feeds the set documents one by one and continuously and automatically conveys them toward the reading contact glass (reading position, not shown). The image reading unit 2b reads a document passing through the feed reading contact glass and a document set on a placement reading contact glass (not shown) to generate image data.

  The paper feed unit 3a accommodates a plurality of sheets. In the MFP 100 according to the present embodiment, two paper feed cassettes 31 are provided as the paper feed unit 3a. When executing a print job, one of the paper feed cassettes 31 feeds the paper one by one to the transport unit 3b. The transport unit 3b transports the paper supplied from the paper feed unit 3a. The image forming unit 3c forms a toner image based on the image data, and transfers the toner image onto the conveyed paper. The fixing unit 3d fixes the toner image transferred to the paper. The paper after toner fixing is discharged to the discharge tray 3e.

(Hardware configuration of image forming apparatus)
Next, an example of a hardware configuration of the image forming apparatus (multifunction peripheral 100) according to the embodiment will be described with reference to FIG. FIG. 2 is a block diagram illustrating an example of the configuration of the multifunction peripheral 100.

  A control unit 4 is provided in the multifunction device 100. The control unit 4 is a control board. The control unit 4 controls the operation of the image forming apparatus. The control unit 4 includes SoC 5 (System-on-a-chip, corresponding to a processing unit). The SoC 5 is an integrated circuit in which a plurality of circuits and chips conventionally arranged in a substrate are combined into one chip. The SoC 5 includes an image processing circuit 51 in addition to a controller 50 (control circuit) and an arithmetic circuit, and controls the operation of the multifunction peripheral 100. In addition, the control part 4 is divided | segmented for every function, and the part which performs control may be provided with multiple types. For example, it can be divided into a main control unit that performs overall control and image processing and an engine control unit that actually controls the printing unit.

  The image processing circuit 51 performs image processing on image data to be printed, such as density conversion, enlargement, reduction, etc., or format conversion of image data read by the image reading unit 2b, according to settings made on the operation panel 1. Perform image processing. The image processing circuit 51 generates image data to be transmitted to the computer 400 or the network 200. The SoC 5 performs control of each unit of the image forming apparatus and various arithmetic processes based on the program and data stored in the storage unit 6.

  The storage unit 6 includes a ROM 61, a RAM 62, and an HDD 63. The storage unit 6 is a combination of nonvolatile and volatile storage devices. The storage unit 6 stores various data such as various programs and data for controlling the multifunction peripheral 100, setting data, and image data. A plurality of types of devices 500 (peripheral devices) can be connected to the multifunction peripheral 100 (details will be described later). The HDD 63 of the storage unit 6 stores a driver software group 63a that is a bundle of driver software of various devices 500 so that the device 500 connected to the multifunction peripheral 100 can be used.

  The control unit 4 is connected to each unit such as the operation panel 1, the document conveying unit 2a, the image reading unit 2b, and the printing unit 3 through a bus, a signal line, or the like. The control unit 4 recognizes the existence of each unit and each device. Then, the control unit 4 controls the operation (scanning operation or printing operation) of the multifunction peripheral 100.

  Further, the control unit 4 is provided with a communication unit 41 including various sockets and a communication control chip. The communication unit 41 is mounted on the substrate of the control unit 4 (may be a separate substrate). The communication unit 41 is communicably connected to the network 200 (for example, LAN) and the facsimile apparatus 300. Further, the communication unit 41 can transmit and receive data to and from the computer 400 (for example, a PC or a server) via the network 200. In addition, by directly connecting the computer and the communication unit 41 with a cable, data communication between the communication unit 41 and the computer can be performed without using a network.

(Device 500 connection and data communication)
Next, connection of the device 500 in the multifunction peripheral 100 according to the embodiment will be described with reference to FIG. FIG. 3 is a diagram for explaining data communication and power supply with the device 500 of the multifunction peripheral 100 according to the embodiment.

  In the following description, an example in which a device 500 (peripheral device) compliant with the USB standard is connected to the multifunction peripheral 100 will be described. In other words, the multifunction device 100 can recognize the connected device 500 and perform data communication based on the USB standard. Note that a device 500 that complies with another standard may be connected to the multifunction peripheral 100 and used.

  The controller 4 (control board) is provided with a host controller 7, a hub 70, and a rear connector 91 (a type of connector 9) as parts for performing data communication with the device 500. Further, a substrate 4a is arranged outside the control unit 4 (control substrate), and a front connector 92 (a kind of connector 9) is provided on the substrate. The back connector 91 and the front connector 92 are female connectors.

  The host controller 7 performs communication control between the device 500 and the control unit 4 (SoC 5) based on the USB standard. The host controller 7 is communicably connected to the SoC 5. The host controller 7 may be built in the SoC 5. Then, the host controller 7 takes the initiative of communication with the device 500. The host controller 7 gives the right to use the data signal line (data bus) to the device 500 to communicate with, and communicates with the device 500 to which the right to use is given.

  In addition, the host controller 7 transfers the received data to the SoC 5. Thereby, the SoC 5 recognizes the data received from the device 500. The SoC 5 generates data indicating a communication partner (any device 500), an operation command, and contents to be stored, and sends the data to the host controller 7. The host controller 7 transfers the data from the SoC 5 to the designated device 500. The host controller 7 can execute other functions defined in the USB standard, but details are omitted.

  The hub 70 mediates communication between the host controller 7 and the device 500 based on the USB standard. The hub 70 is communicably connected to the host controller 7. The hub 70 is also connected to the connector 9. The hub 70 connects the host controller 7 and the device 500 that the host controller 7 intends to communicate with. In other words, the hub 70 has a function of distributing data (signal).

  The hub 70 detects the connection of the device 500 to the connector 9 and detects the communication speed of the device 500. When the hub 70 detects connection of the device 500 to the connector 9, the hub 70 notifies the host controller 7. The host controller 7 informs the SoC 5 of the notification content from the hub 70. When the hub 70 detects the communication speed of the device 500, the hub 70 notifies the host controller 7 of the communication speed of the device 500. The hub 70 can execute other functions defined in the USB standard, but details are omitted.

  The control unit 4 (control board) is provided on the back side of the multifunction device 100. Therefore, the back connector 91 provided on the control board is exposed on the back side of the multi-function device 100. Accordingly, when the rear connector 91 is used, the cable C1 and the device 500 are inserted into the rear surface of the multi-function device 100. In this description, an example in which one connector 9 is provided on the rear surface of the multifunction device 100 and one connector 9 is provided on the front surface of the multifunction device 100 will be described. However, a plurality of connectors 9 may be provided.

  The front connector 92 is provided on the front side of the operation panel 1. In the multifunction machine 10 of the present embodiment, the front connector 92 is provided on a substrate in the operation panel 1. The user can easily insert the device 500 and the cable C1 into the front connector 92 (operation panel 1).

  The control unit 4 (control board) is provided on the back side of the multifunction device 100, and the front connector 92 is provided on the front surface of the multifunction device 100. In other words, the front connector 92 is positioned away from the control unit 4. Therefore, the board 4a of the front connector 92 and the control unit 4 are connected by the harness H1. One end of the harness H <b> 1 is connected to the hub 70 of the control unit 4, and the other end of the harness H <b> 1 is connected to the front connector 92.

  To each connector 9 (rear connector 91, front connector 92), the device 500 is connected directly or a cable C1 attached to the device 500 is connected. For example, a device in which a male connector (device connector 501) such as a USB memory or a wireless LAN adapter is provided integrally with the substrate of the device 500 is directly inserted into each connector 9. In addition, a device in which the cable C1 is fixedly attached to the device 500 and the male device connector 501 is attached to the end of the cable C1, such as a keyboard, a mouse, a memory card reader, and an external hub, The male device connector 501 at the end of C1 is inserted into each connector 9. A device 500 having a female device connector 501 such as a digital camera or an external HDD is connected to the connector 9 via a cable C1 having male connectors at both ends.

  FIG. 3 shows an example in which the device 500 is connected to the connector 9 via both the rear connector 91 and the front connector 92 via a cable C1 having male connectors at both ends.

  Each connector 9 (rear connector 91, front connector 92) has a shape based on the USB standard and has a terminal based on the USB standard. Specifically, the USB standard is a serial communication method, and data communication is performed using a differential signal. For data communication, each connector 9 has at least two terminals D + and D−. When the device connector 501 attached to the device 500 or the cable C1 extending from the device 500 is directly inserted into each connector 9, the D + and D− terminals of each connector 9 and the D + and D− of the device connector 501 are in contact. When the device 500 is connected using the cable C1, the D + and D− signal lines in the cable C1 connect the D + and D− terminals of each connector 9 to the D + and D− terminals of the device connector 501. . Further, in FIG. 3, the data signal line is shown by a single solid line for simplification.

  When the device 500 is connected to the rear connector 91, the host controller 7 and the device 500 are connected by a data signal line via the hub 70, the rear connector 91, and possibly the cable C1. Thereby, data communication between the host controller 7 and the device 500 connected to the rear connector 91 becomes possible.

  When the device 500 is connected to the front connector 92, the host controller 7 and the device 500 are connected by a data signal line via the hub 70, the harness H1, the front connector 92, and possibly the cable C1. Thereby, data communication between the host controller 7 and the device 500 connected to the front connector 92 becomes possible.

  The SoC 5 and the host controller 7 recognize the connected device 500. Each USB standard device 500 stores in its internal device memory 502 a descriptor in which various information related to the device 500 is written. In other words, the device 500 stores the device code 503 including information such as the type of the device 500 and the manufacturer.

  Specifically, the device code 503 (descriptor) includes the class, subclass, protocol, vendor ID, product ID, maximum power consumption, device 500 attribute, maximum packet length that can be used for transfer, transfer interval, and the like. Is described. The host controller 7 acquires a descriptor from the device 500. Then, the SoC 5 obtains a descriptor from the host controller 7. The SoC 5 recognizes what device 500 the connected device 500 is based on information described in a descriptor (device code 503) such as the class and subclass of the device 500. Note that the host controller 7 may recognize what the connected device 500 is and transmit the recognition result to the SoC 5.

(Power supply to device 500)
Next, power supply to the device 500 in the multifunction peripheral 100 according to the embodiment will be described with reference to FIG.

  First, in FIG. 3, the power supply path to the device 500 is indicated by a broken line. And as a part which produces | generates the voltage with respect to the device 500 connected to any connector 9, and supplies electric power, primary power supply A1, DCDC converter 8 (equivalent to a power circuit), switch part 80, each connector 9 (back connector 91, front connector 92) are provided.

  The primary power supply A1 is connected to a commercial power source (outlet) by a power cord (not shown). Then, the AC voltage supplied from the commercial power source is rectified and stepped down to generate a DC voltage (for example, DC 24 V) for driving a motor provided in the multifunction peripheral 100. The motor is a motor that rotates a rotating body for paper feeding, paper conveyance, toner image formation, fixing, and paper discharge.

  The DCDC converter 8 is provided in the control unit 4 (control board). Note that the DCDC converter 8 may be provided outside the substrate. The DCDC converter 8 is a power conversion circuit that steps down the voltage supplied from the primary power supply device A1. The DCDC converter 8 of this embodiment includes a backflow prevention diode, a coil, a capacitor for charging electric charge, and a transistor. This transistor performs ON / OFF switching of application of the output voltage of the primary power supply device A1 to the capacitor, and adjusts the output voltage of the capacitor (the output voltage of the DCDC converter 8). Thus, the DCDC converter 8 is a switching power supply (for example, a chopper type). The DCDC converter 8 may be another type.

  An output controller 8 a is provided inside the DCDC converter 8. The output controller 8 a receives an instruction from the SoC 5 and controls the output voltage value of the DCDC converter 8. The output controller 8a controls transistor switching. When receiving an instruction to increase the output voltage value from the SoC 5, the output controller 8a increases the ON duty ratio (pulse width) of switching to increase the output voltage value of the DCDC converter 8. When receiving an instruction to decrease the output voltage value from the SoC 5, the output controller 8a decreases the output voltage value of the DCDC converter 8 by reducing the ON duty ratio (pulse width).

  The switch unit 80 is a circuit for collectively turning ON / OFF the power supply to the hub 70, the back connector 91, the front connector 92, and the device 500. For example, the switch unit 80 is a chip that performs switching. Further, the switch unit 80 may include a current limiting circuit so that a current having a magnitude larger than that specified in the standard does not flow to the connector 9 or the device 500.

  When shifting to the power saving mode because the predetermined transition condition is satisfied, the SoC 5 turns off the switch unit 80. As a result, power supply to the hub 70, the back connector 91, the front connector 92, and the device 500 can be stopped. On the other hand, when the predetermined return condition is satisfied, the SoC 5 turns on the switch unit 80 when canceling the power saving mode and shifting to the normal mode (a state in which the MFP 100 can execute a print or transmission job). To do. Thereby, the power supply to the power supply to the hub 70, the back connector 91, the front connector 92, and the device 500 can be restarted collectively.

  The voltage (electric power) generated by the DCDC converter 8 is supplied (input) to the hub 70 and each connector 9 (rear connector 91, front connector 92) via the switch unit 80. Note that the voltage generated by the DCDC converter 8 is input to the front connector 92 via the harness H1. The hub 70 may branch the output voltage (power) of the DCDC converter 8. In this case, the voltage generated by the DCDC converter 8 is input to the rear connector 91 via the hub 70. The voltage generated by the DCDC converter 8 is input to the front connector 92 via the hub 70 and the harness H1.

  In the USB standard, there are Vbus and GND (ground) as lines related to the power supply. Therefore, each connector 9 (rear connector 91, front connector 92) has two terminals, Vbus and GND, as power supply terminals. The Vbus and GND terminals of each connector 9 are connected to the Vbus and GND of the device connector 501.

  Specifically, the device 500 is connected directly to each connector 9 (the rear connector 91 and the front connector 92) or the cable C1 attached to the device 500 is connected. For example, the male device connector 501 is attached when a device in which the male device connector 501 is provided integrally with the board of the device 500 is directly inserted into each connector 9 and at the end of the cable C1. When the device is inserted into each connector 9, the Vbus and GND terminals of the connector 9 and the Vbus and GND of the device connector 501 are in contact with each other. Further, when the device 500 having the female device connector 501 and each connector 9 are connected via the cable C1 having male connectors at both ends, two power lines Vbus and GND in the cable C1 are provided. The Vbus and GND terminals of each connector 9 and the Vbus and GND terminals of the device connector 501 are connected. In FIG. 3, a single power supply line is illustrated in a simplified manner.

(Change of output of power supply circuit due to connection of device 500)
Next, the change of the output of the power supply circuit (DCDC converter 8) accompanying the connection of the device 500 will be described with reference to FIGS. FIG. 4 is a flowchart illustrating an example of the flow of processing for changing the output of the power supply circuit (DCDC converter 8) accompanying the connection of the device 500. FIG. 5 is a diagram illustrating an example of the device registration screen S1.

  In the MFP 100 according to the present embodiment, the DCDC converter 8 supplies power to the hub 70, the connectors 9 (the rear connector 91 and the front connector 92), and the device 500. The DCDC converter 8 applies a voltage to the hub 70, each connector 9, and the device 500 through the switch unit 80.

  The DCDC converter 8 outputs the first voltage when the device 500 is not connected. The first voltage is 5 V in the multifunction peripheral 100 of the present embodiment. In the USB standard, regarding the power supply, the specified range of the voltage input to the device 500 is about DC 4.75 to 5.25V. Therefore, the SoC 5 causes the DCDC converter 8 to output the first voltage that is a voltage within the specified voltage range. Specifically, the SoC 5 gives the DCDC converter 8 an instruction to output DC 5.0 V, which is the median value of the specified voltage range. When the device 500 is not connected, no current flows to the device 500, so the voltage applied to the switch unit 80, the hub 70, and each connector 9 is approximately 5V.

  The output of the DCDC converter 8 can also be input to a circuit in the SoC 5, the host controller 7, and the storage unit 6 (see FIG. 3). In other words, the DCDC converter 8 inputs a voltage to a portion of the SoC 5, the host controller 7, and the storage unit 6 that requires a DC 5 V voltage.

  Here, when the device 500 is connected to any one of the connectors 9, a current flows toward the device 500. The switch unit 80, the hub 70, the connector 9, the cable C1, and the harness H1 each have an impedance (resistance). Therefore, the voltage input to the device 500 is smaller than the first voltage. In addition, when the device 500 is connected to the front connector 92, power is supplied to the device 500 via the harness H1. Therefore, when the same device 500 is connected to the rear connector 91 and the front connector 92, the voltage input to the device 500 is theoretically lower when the device is connected to the front connector 92 because of a voltage drop in the harness H1. Becomes smaller.

  And the magnitude | size of the voltage which falls by the switch part 80, the hub 70, the connector 9, the cable C1, and the harness H1 theoretically becomes a resistance component x electric current. Therefore, the larger the current flowing through the device 500, the smaller the voltage input to the device 500. Note that, according to the USB standard, the maximum current supplied to the device 500 is 500 mA (USB 2.0) or 900 mA (USB 3.0).

  Even when a current of 500 mA or 900 mA is passed through the device 500, the magnitude of the voltage input to the device 500 needs to be a value within a specified voltage range. When the voltage input to the device 500 falls below the specified voltage range, there are cases where the device 500 malfunctions, the device 500 becomes unstable, or the device 500 does not operate.

  Therefore, when a pre-registered device 500 (registered device) is connected to one or both of the rear connector 91 and the front connector 92, the SoC 5 applies a second voltage higher than the first voltage to the DCDC converter. 8 to output.

  And the memory | storage part 6 memorize | stores the registration device data D1 which is the data which defined the registration device. In the default (initial setting) registered device data D1, a hard disk drive (USB external hard disk) and a wireless LAN adapter (USB wireless LAN device) are registered as registered devices. This is because the hard disk drive and the wireless LAN adapter generally have a large load current. Thus, the device 500 can be registered based on the type (class, usage) of the device 500. When the type of device 500 is registered, all devices 500 belonging to the registered type are treated as registered devices. For example, when a hard disk drive is registered, a device 500 recognized as a hard disk drive is treated as a registered device regardless of the model or vendor.

  On the other hand, in the default (initial setting) registered device data D1, a device 500 such as a semiconductor memory (flash ROM type USB memory) or a keyboard is not included as a registered device. As described above, in the MFP 100 according to the present embodiment, the default registered device data D1 is data that defines the type (class, application) of the device 500 that is considered to have a large current required for operation. Note that it is possible to appropriately determine which type of device 500 is registered and which type of device 500 is not registered.

  In addition, the type and model of the registered device can be added or changed. Here, the additional registration of the model and type of the device 500 will be described with reference to FIG.

  The device registration screen S1 illustrated in FIG. 5 can be displayed by performing a predetermined operation on the touch panel unit 12 and the hard keys 13 of the operation panel 1.

  The device 500 currently connected to the front connector 92 or the rear connector 91 can be registered. The SoC 5 causes the display unit 11 to display information indicating the device 500 connected to each connector 9 in the device registration screen S1. The information indicating the device 500 is based on the device code 503 (descriptor) acquired from the device 500 by the SoC 5 (host controller 7). In FIG. 5, xxx indicates that the vendor's USB memory is connected to the front connector 92. Thus, the display unit 11 displays the vendor name and the type of the device 500 as information on the connected device 500.

  In order to register the connected device 500, a specific device registration key K1 is provided (see FIG. 5). When the operation panel 1 accepts an operation on the specific device registration key K1, the SoC 5 causes the storage device 6 to update the registered device data D1. At this time, the SoC 5 adds data (for example, model name, vendor, class) indicating the connected device 500 to the registered device data D1.

  In addition, a check box CB for adding or changing the type (class, usage) of the device 500 handled as a registered device is arranged on the device registration screen S1. The user can set the type of the device 500 to be handled as a registered device by turning on / off the check box CB. FIG. 5 shows a state in which settings for handling the external HDD and the wireless LAN adapter as registered devices are made (the same as the default setting).

  A registration key K2 is provided at the lower right of the device registration screen S1. After checking a desired check box CB, the user touches the display position of the registration key K2 (operates the registration key K2). Operation panel 1 accepts a touch on the display position of registration key K2. When the registration key K2 is operated, the SoC 5 causes the storage unit 6 to update the registered device data D1. At this time, the SoC 5 stores data indicating the type of the checked device 500 in the storage unit 6 as registered device data D1. As a result, it is possible to add a type of device 500 that is treated as a registered device, or to change a certain type of device 500 so that it is not treated as a registered device.

  As described above, the operation panel 1 receives a setting for adding a certain device 500 as a registered device. Then, the storage unit 6 updates the registered device data D1 in accordance with the setting made on the operation panel 1.

  Next, an example of a processing flow when the device 500 is connected to the connector 9 will be described with reference to FIG. The start in FIG. 4 is the time when the multifunction device 100 is activated (when the normal mode is entered) by turning on the main power or returning from the power saving mode. Note that the flowchart of FIG. 4 is continued after the MFP 100 is activated until it enters the power saving mode or until the main power is turned off. In other words, the flow ends when the MFP 100 enters the power saving mode or when the main power is turned off.

  First, the SoC 5 causes the DCDC converter 8 to generate and output the first voltage (DC5V) (step # 1). In addition, the SoC 5 turns on the switch unit 80 (step # 2). As a result, a voltage is applied to the hub 70, the rear connector 91, and the front connector 92.

  The SoC 5 communicates with the host controller 7 and the hub 70 to check whether or not the connection of the new device 500 to the rear connector 91 or the front connector 92 has been detected (step # 3). In other words, the SoC 5 detects that the device 500 is newly connected to the connector 9 via the host controller 7 and the hub 70.

  The SoC 5 continues the confirmation until it can detect the connection of the new device 500 (No in step # 3 → step # 3). The SoC 5 continues to output the first voltage to the power supply circuit when the device 500 is not connected to each connector 9.

  When the connection of the new device 500 can be detected (Yes in Step # 3), the SoC 5 starts communication with the device 500 connected to the connector 9 via the host controller 7 and the hub 70 (Step # 4). . Then, the SoC 5 acquires a device code 503 (descriptor) indicating the type of the device 500 from the device 500 newly connected to the connector 9 (step # 5).

  Then, the SoC 5 recognizes what device 500 is newly connected based on information such as the type, class, usage, vendor, and model name of the device 500 included in the acquired device code 503 (descriptor). (Step # 6). As described above, the SoC 5 acquires the device code 503 indicating the type of the device 500 from the device 500 connected to the connector 9, and selects the device 500 (type of the device 500) connected to the connector 9 based on the device code 503. recognize.

  Subsequently, the SoC 5 refers to the registered device data D1 in the storage unit 6 and confirms whether or not the newly connected device 500 is a registered device (step # 7). When the newly connected device 500 is a registered device (Yes in step # 7), the SoC 5 causes the DCDC converter 8 (power supply circuit) to output the second voltage (step # 8).

  Here, the second voltage is a voltage considering a voltage drop. The second voltage is greater than the first voltage. Further, the magnitude of the second voltage is such that the voltage input (applied) to the device 500 connected to the connector 9 (the rear connector 91 and the front connector 92) is a voltage within a predetermined specified voltage range. Is set. Thus, the SoC 5 sets the output voltage value of the DCDC converter 8 to a higher value (sets to the second voltage) so that the voltage input to the device 500 is within the specified voltage range even if there is a voltage drop. ).

  To what extent the second voltage is made larger than the first voltage can be determined as appropriate. For example, an experiment is performed, various devices 500 are connected, and a voltage and a voltage drop input to the device 500 are measured. Then, the magnitude of the second voltage may be determined based on the experimental result.

  Further, the magnitude of the second voltage may be determined by calculation so that a value obtained by multiplying the first voltage by a predetermined ratio becomes the voltage value of the second voltage. For example, when the voltage value of the first voltage is increased by 3%, the predetermined ratio is 103%.

  Even if the DCDC converter 8 outputs the second voltage, there may be a case where almost no voltage drop occurs. In such a case, it is necessary to prevent a voltage exceeding the specified voltage range from being input to the device 500. Therefore, the second voltage may have a maximum value within the specified voltage range. In the present embodiment, since the maximum value of the specified voltage range is 5.25V, the second voltage is set to a value smaller than 5.25V.

  Specifically, in the present embodiment, the second voltage is about 5.15V. In this way, the second voltage is also larger than the first voltage, but is a value within the specified voltage range. The magnitude of the voltage that drops from the DCDC converter 8 to the power supply input terminal of the device 500 when a maximum current according to the standard flows is various. For example, the voltage drop in the path from the DCDC converter 8 to the device 500 In the case of 0.3V, 5.15−0.3 = 4.85V. 4.85V is a voltage within a specified voltage range.

  After the DCDC converter 8 generates and outputs the second voltage, the SoC 5 checks whether or not all the registered devices have been removed (step # 9). The SoC 5 continues to output the second voltage to the DCDC converter 8 until all the registered devices are removed (No in Step # 9 → Step # 8). On the other hand, when all the registered devices have been removed (Yes in step # 9), the flow returns to step # 1.

  On the other hand, when the connected device 500 is not a registered device (No in step # 7), the SoC 5 checks the voltage values at the voltage measurement positions P1 and P2 detected by the detection circuit 81 (step # 10). In the multi-function device 100 of this embodiment, voltage measurement positions P1 and P2 are provided on the power supply line from the DCDC converter 8 (power supply circuit) to the device 500 (see FIG. 3). In FIG. 3, a signal flow concerning detection of the voltages at the voltage measurement positions P <b> 1 and P <b> 2 and notification of the voltage value of the SoC 5 is indicated by a two-dot chain line.

  Specifically, the voltage measurement position P1 is provided in the middle of the power supply line from the DCDC converter 8 (power supply circuit) to the device 500 via the back connector 91. The voltage measurement position P2 is provided in the middle of the power supply line from the DCDC converter 8 (power supply circuit) to the device 500 via the front connector 92.

  And the detection circuit 81 for detecting the voltage value of voltage measurement position P1, P2 is provided (refer FIG. 3). The detection circuit 81 may be a chip that performs A / D conversion, recognizes the voltage values at the voltage measurement positions P1 and P2, and notifies the SoC 5 of the voltage values. Alternatively, the detection circuit 81 may be built in the SoC 5, and the SoC 5 may directly detect the voltage values at the voltage measurement positions P1 and P2.

  Even if the device 500 connected to each connector 9 is not a registered device, there is a case where a large current flows and a voltage input to the device 500 falls below a specified voltage range. Therefore, the SoC 5 confirms whether or not the output of the DCDC converter 8 should be the second voltage based on the voltage values at the voltage measurement positions P1 and P2 (step # 11).

  The SoC 5 is in a state where the device 500 is connected to the connector 9 (front connector 92, rear connector 91), and the voltage at any one of the voltage measurement positions P1 and P2 is equal to or lower than an allowable value (Yes in step # 11). The DCDC converter 8 is caused to generate and output the second voltage (step # 12). Here, the allowable value can be determined as appropriate. For example, for the voltage measurement position P1, the allowable value may be the voltage at the voltage measurement position P1 when the voltage input to the device via the rear connector 91 is the minimum value in the specified voltage range. For the voltage measurement position P2, the allowable value may be the voltage at the voltage measurement position P2 when the voltage input to the device via the harness H1 and the front connector 92 is the minimum value in the specified voltage range. In this way, the allowable value may be varied for each voltage measurement position. The allowable value may be the same value at all voltage measurement positions.

  Further, when the value obtained by adding the absolute value of the difference between the first voltage and the second voltage to the voltage at the voltage measurement position P1 or P2 is smaller than the maximum value in the specified voltage range, the SoC 5 outputs the output of the DCDC converter 8 to the second value. It may be determined that the voltage should be used.

  Then, the SoC 5 checks whether or not all the devices 500 that are not registered devices and whose voltage at any of the voltage measurement positions P1 and P2 is equal to or lower than the allowable value have been removed (step # 13). The SoC 5 continues to output the second voltage to the DCDC converter 8 until all of the device 500 is removed (No in Step # 13 → Step # 12). On the other hand, when all of the devices 500 are removed (Yes in step # 13), the flow returns to step # 1.

  On the other hand, even when the device 500 is connected to the connector 9 (the front connector 92 and the rear connector 91), the SoC 5 is in a state where the voltages at all the voltage measurement positions P1 and P2 exceed the allowable values (in step # 11). No), the SoC 5 generates the first voltage in the DCDC converter 8 and continues the output (step # 14). Thus, when the connected device 500 is not a registered device (even if the device 500 is connected to the connector 9), the SoC 5 causes the DCDC converter 8 to output the first voltage. Then, the flow returns to step # 3.

As described above, the image forming apparatus (multifunction peripheral 100) according to the embodiment includes the connector 9 (the rear connector 91 and the front connector 92) for connecting the device 500 directly or via the cable C1.
The power supply circuit (DCDC converter 8) that supplies power to the device 500 connected to the connector 9 communicates with the device 500 connected to the connector 9, recognizes the device 500 connected to the connector 9, and When the device 500 is not connected, the first voltage is output to the power supply circuit, and while the device 500 is connected to the connector 9, the first voltage is higher than the first voltage and input to the device 500 connected to the connector 9. And a processing unit (SoC5) that causes the power supply circuit to output a second voltage that is a voltage within a specified voltage range that is a predetermined voltage range.

  Thereby, only when the device 500 is connected to the connector 9 (the rear connector 91 and the front connector 92), the output voltage of the power supply circuit (DCDC converter 8) is made larger than the normal voltage (first voltage). Therefore, even when the device 500 having a large flowing current (load current) is connected, a voltage within the specified voltage range is input to the device 500. Therefore, a voltage within a specified range can be applied to the device 500 regardless of the type of the device 500 connected to the connector 9 (the rear connector 91 and the front connector 92). Therefore, the connected device 500 does not become unstable. Further, malfunction of the connected device 500 does not occur. Further, the connected device 500 can be reliably operated.

  Furthermore, since a voltage within a specified range is reliably input to the device 500, it is possible to comply with the specifications of the standard. Therefore, it is possible to easily pass the standard test. Further, when there is no need, the output of the power supply circuit (DCDC converter 8) is in a state where it is dropped to the first voltage, so that wasteful power consumption can be suppressed.

  The image forming apparatus (multifunction device 100) includes a storage unit 6 that stores registered device data D1 indicating a device 500 registered in advance. The processing unit (SoC5) acquires the device code 503 indicating the type of the device 500 from the device 500 connected to the connector 9 (the rear connector 91 and the front connector 92), and is connected to the connector 9 based on the device code 503. When the device 500 is recognized and the connected device 500 is a registered device, the power supply circuit (DCDC converter 8) outputs a second voltage, and when the connected device 500 is not a registered device (the device 500 is connected to the connector 9). If it is connected), the first voltage is output to the power supply circuit.

  The connected device 500 is a device 500 that consumes a large amount of current, and when a large current flows, the voltage drop in the power supply line from the power supply circuit (DCDC converter 8) to the connected device 500 increases (connector 9). , The voltage drop in each part such as the cable C1 and the harness H1 becomes large). Therefore, a device 500 in which the value of the voltage input to the device 500 is below the specified voltage range is registered in advance. Then, only when the registered device is connected, the processing unit (SoC 5) increases the output voltage value of the power supply circuit to the second voltage value. In other words, when the registration device is connected, the output voltage value of the power supply circuit is changed from the first voltage to the second voltage. As a result, when there is a high possibility that the magnitude of the voltage input to the device 500 falls below the specified voltage range, the output voltage value of the power supply circuit is automatically set higher. Even if the connected device 500 is not a registered device and does not have the second voltage, when the voltage in the specified voltage range can be input to the device 500, the output voltage value of the power supply circuit is maintained at the first voltage. Thus, the magnitude of the output voltage of the power supply circuit can be adjusted according to the situation. Therefore, it is possible to reduce the power consumption of the image forming apparatus as compared with the case where a margin is provided and the output voltage value of the power supply circuit is set higher from the beginning.

  The image forming apparatus (multifunction device 100) includes an operation panel 1 that receives settings and operations by the user. The operation panel 1 receives a setting for adding a certain device 500 as a registered device. The storage unit 6 updates the registered device data D1 in accordance with the settings made on the operation panel 1.

  Thereby, the user himself / herself can determine what kind of device 500 is treated as a registered device. Therefore, the user can freely set. In addition, a device 500 that has a problem such as unstable operation when connected and may have a large flowing current can be registered as a registered device. Thereby, the device 500 can be stably operated.

  The image forming apparatus (multifunction device 100) includes a detection circuit 81 that detects voltage values at voltage measurement positions P1 and P2 provided on a power supply line from the power supply circuit (DCDC converter 8) to the device 500. The processing unit (SoC5) detects the voltage values at the voltage measurement positions P1 and P2 based on the output of the detection circuit 81, and the device 500 is connected to the connector 9 (the rear connector 91 and the front connector 92). When the voltage at the voltage measurement positions P1 and P2 is less than the allowable value, the second voltage is output to the power supply circuit, and the voltage at the voltage measurement positions P1 and P2 is the allowable value with the device 500 connected to the connector 9. Is exceeded, the first voltage is output to the power supply circuit.

  As a result, when the voltage value at the voltage measurement positions P1 and P2 becomes small and the voltage input to the device 500 may fall below the specified voltage range, the output voltage value of the power supply circuit (DCDC converter 8) is automatically set. Can be bigger. Therefore, the device 500 connected to the connector 9 (the rear connector 91 and the front connector 92) can be stably operated.

  The processing unit (SoC 5) and the power supply circuit (DCDC converter 8) are provided on the same substrate. The power supply line from the power supply circuit and the data signal line from the processing unit are connected to the connector 9 (front connector 92) by the harness H1. Thereby, the harness H1 is used, and even when the voltage input to the device 500 is likely to fall below the specified voltage range due to the voltage drop in the harness H1, the voltage within the specified voltage range is surely input to the device 500. Can do.

  Next, another embodiment will be described. In the description of the above embodiment, an example in which the output of the DCDC converter 8 (power supply circuit) is determined based on whether or not the device is a registered device and the voltage detected by the detection circuit 81 has been described. However, without confirming whether the device is a registered device or the magnitude of the detection voltage by the detection circuit 81, the SoC 5 determines the output voltage value of the DCDC converter 8 when the device 500 is connected. Two voltages may be used, and when no device 500 is connected, the output voltage value of the DCDC converter 8 may be the first voltage.

  Although the embodiment of the present invention has been described, the scope of the present invention is not limited to this, and various modifications can be made without departing from the spirit of the invention.

  The present invention can be used for an image forming apparatus and an image forming system including the image forming apparatus and an information processing apparatus.

DESCRIPTION OF SYMBOLS 100 Multifunctional device (image forming apparatus) 1 Operation panel 5 SoC (processing part) 6 Storage part 8 DCDC converter (power supply circuit) 81 Detection circuit 9 Connector 91 Rear connector (connector)
92 Front connector (connector) 500 Device 503 Device code C1 Cable D1 Registered device data H1 Harness P1 Voltage measurement position P2 Voltage measurement position

Claims (4)

A connector for connecting the device directly or via a cable;
A power supply circuit for supplying power to a device connected to the connector;
Communicating with a device connected to the connector, recognizing the device connected to the connector, and when no device is connected to the connector, causing the first voltage to be output to the power supply circuit; While connected, a second voltage that is greater than the first voltage and that is a voltage within a specified voltage range in which a voltage input to a device connected to the connector is a predetermined voltage range is A processing unit for outputting to the power supply circuit;
A storage unit for storing registered device data indicating a registered device registered in advance,
The processing unit obtains a device code indicating a device type from the device connected to the connector, recognizes the device connected to the connector based on the device code, and the connected device is the registered device. The image forming apparatus , wherein the power supply circuit outputs the second voltage, and the power supply circuit outputs the first voltage when the connected device is not the registered device . Includes an operation panel that accepts user settings and operations,
The operation panel accepts a setting for registering a certain device as the registered device,
The image forming apparatus according to claim 1 , wherein the storage unit updates the registered device data in accordance with a setting made on the operation panel. A detection circuit for detecting a voltage value at a voltage measurement position provided on a power supply line from the power supply circuit to the device;
The processing unit detects the voltage value at the voltage measurement position based on the output of the detection circuit, and when the voltage at the voltage measurement position is equal to or less than an allowable value in a state where a device is connected to the connector, The second voltage is output to the power supply circuit, and the first voltage is output to the power supply circuit when the voltage at the voltage measurement position exceeds the allowable value in a state where a device is connected to the connector. the image forming apparatus according to claim 1 or 2, characterized in that to. The processing unit and the power supply circuit are provided on the same substrate,
Data signal lines from the power supply line and the processing unit from the power supply circuit, an image forming apparatus according to any one of claims 1 to 3, characterized in that it is connected to the connector by a harness.

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