JP2011223355A - Network apparatus and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus that can detect a disconnection of a network during non-operation of a CPU that controls operation of the apparatus.SOLUTION: A multiple functional machine 10 comprises: a main CPU 11 for controlling the operation of the multiple functional machine 10; a network I/F 21 for communicating with external devices via a network 2; and a sub CPU 12 for detecting a disconnection of the network 2 on the network I/F 21 during non-operation of the main CPU 11. Even when the main CPU 11 does not operate because of a power off state or a power saving mode of the multiple functional machine 10, the sub CPU 12 monitors the disconnection of the network 2 on the network I/F 21, thereby allowing securing of security for an unauthorized disconnection and connection on the network during non-operation of the main CPU 11.

Description

  The present invention relates to a network apparatus and an image forming apparatus having a security function against unauthorized disconnection and connection of a network.

  In a network device having a network communication function, there is a possibility that a network cable may be illegally cut and connected and misused, so a technique for taking this security measure has been devised.

  For example, in order to prevent the transmission line between the security device and the host device from being illegally disconnected and connected to a repeater, and to prevent data from being illegally leaked from the repeater, the security device has detected a network disconnection. In such a case, a technique has been devised in which the connection with the disconnected network is automatically disconnected (see Patent Document 1).

JP 2006-217551 A

  However, in the above technique, when the CPU (Central Processing Unit) is not operating in the power-off state or the power saving mode of the apparatus and the disconnection of the network is not monitored, the disconnection of the network cannot be detected. There is a problem that it is impossible to ensure security against unauthorized disconnection and connection of the network when the CPU is not operating.

  For example, if the CPU is illegally connected to another network with low safety when the CPU is not operating, immediately after the CPU starts up, initializes the network and establishes communication (before security protection), etc. There is a risk of being attacked through the reconnected network.

  SUMMARY An advantage of some aspects of the invention is to provide a network device and an image forming apparatus that can detect a disconnection of a network when a CPU that controls the operation of the device is not operating. .

  The gist of the present invention for achieving the object lies in the inventions of the following items.

[1] a first CPU that controls the operation of the network device;
A network interface unit that communicates with an external device through a network;
A second CPU that detects disconnection of the network in the network interface unit when the first CPU is not operating;
A network device comprising:

  In the above invention, when the first CPU that controls the operation of the network device is not operating, the second CPU detects a disconnection of the network in the network interface unit. Thereby, the disconnection of the network can be detected when the CPU (first CPU) that controls the operation of the apparatus is not operating.

  For example, even when the first CPU is not operating in the power-off state or the power saving mode of the apparatus, the second CPU monitors the disconnection of the network in the network interface unit. It is possible to secure security against unauthorized disconnection and connection of the network.

[2] The network device according to [1], wherein the second CPU detects disconnection of the network in the network interface unit even when the first CPU operates.

  In the above invention, the load on the first CPU can be reduced as compared with the case where the disconnection of the network is also detected when the first CPU is operating (controlling the operation of the network device). .

[3] The network device according to [1] or [2], wherein when the disconnection of the network is detected, the second CPU stops the communication operation of the network interface unit.

  In the above invention, when the second CPU detects a disconnection of the network in the network interface unit of the network device, the second CPU stops the communication operation of the network interface unit. Thus, for example, even when the network connected to the network interface unit is illegally switched to another network when the first CPU is not operating, communication between the network and the network device (network interface unit) is not performed. It is blocked, and it is possible to prevent the network device from being attacked through the network. Similarly, when the network connected to the network interface unit is illegally switched to another network during the operation of the first CPU, the second CPU detects the disconnection of the network in the same manner. Since the communication operation is stopped, communication between the reconnected network and the network device (network interface unit) is blocked, and the network device can be prevented from being attacked through the network.

[4] When the disconnection of the network is detected, the second CPU notifies the first CPU that the disconnection of the network is detected when the first CPU operates. The network device according to any one of [1] to [3].

  In the above invention, when the second CPU detects a disconnection of the network in the network interface unit of the network device when the first CPU is not operating, the first CPU notifies the start when the first CPU starts operating. Receive. When the second CPU detects a disconnection of the network during the operation of the first CPU, the first CPU receives a notification from the second CPU during the operation.

[5] The network device according to [4], wherein when receiving the notification, the first CPU notifies the user that a disconnection of the network has been detected.

  In the above invention, the disconnection of the network in the network interface unit detected when the first CPU is not operating or operating (when the network device is operating) is notified to the user. The user who has received this notification can take measures such as checking the network cable connected to the network interface unit of the network device.

[6] When the second CPU stops the communication operation of the network interface unit, the second CPU notifies the first CPU that the disconnection of the network has been detected during the operation of the first CPU,
Upon receiving the notification, the first CPU displays a network connection screen, and when receiving a predetermined operation through the network connection screen, the first CPU cancels the stop of the communication operation of the network interface unit. ] The network apparatus as described in.

  In the above invention, when the second CPU detects the disconnection of the network in the network interface unit and stops the communication operation of the network interface unit, the second CPU notifies that the disconnection of the network is detected during the operation of the first CPU. When the first CPU receives the notification from the second CPU, it displays a network connection screen. When a predetermined operation is received through the network connection screen, the stop of the communication operation of the network interface unit is released.

  Thus, when the network disconnection is detected and the communication operation of the network interface unit is stopped, the user can cancel the stop of the communication operation of the network interface unit by performing a predetermined operation through the network connection screen. it can.

[7] The network device according to any one of [1] to [6];
An image forming unit that is controlled by the first CPU to form an image based on image data on a recording sheet;
An image forming apparatus comprising:

  In the above invention, in an image forming apparatus provided with a network device (network communication function), it is possible to detect disconnection of the network when the CPU that controls the operation of the device is not operating.

  According to the network apparatus and the image forming apparatus of the present invention, it is possible to detect disconnection of the network when the CPU that controls the operation of the apparatus is not operating. As a result, it is possible to ensure security against unauthorized disconnection and connection of the network when the CPU that controls the operation of the apparatus is not operating.

1 is a block diagram illustrating a configuration of a multifunction peripheral as an image forming apparatus according to a first exemplary embodiment of the present invention. 3 is a flowchart showing the operation of the sub CPU according to the first embodiment of the present invention. It is a flowchart which shows operation | movement of the main CPU which concerns on the 1st Embodiment of this invention. It is a figure which shows an example of the warning screen which concerns on the 1st Embodiment of this invention. It is a flowchart which shows the modification of operation | movement of a sub CPU. It is a flowchart which shows operation | movement of the sub CPU which concerns on the 2nd Embodiment of this invention. It is a flowchart which shows operation | movement of the main CPU which concerns on the 2nd Embodiment of this invention. It is a figure which shows an example of the password input screen which concerns on the 2nd Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[First Embodiment]
FIG. 1 is a block diagram showing a configuration of a multifunction machine 10 as an image forming apparatus according to the first embodiment of the present invention.

  The multifunction machine 10 optically reads an image of a document, prints a duplicate image on a recording sheet, and outputs it, stores the image data of the read document as a file, and stores it in a terminal device or server via a network. A scanning function for transferring data, a printer function for printing an image relating to print data received from a terminal device via a network and an image relating to image data stored in the multifunction device 10 on a recording paper, and output and transmission / reception of image data Facsimile function is provided.

  The multi-function device 10 is a multi-processor system device having two CPUs. The main CPU (first CPU) for controlling the operation of the multi-function device 10 is disconnected from the network at least when the main CPU is not operating. And a sub CPU (second CPU) for detection. Of these two CPUs, the one with higher processing capability is the main CPU and the one with lower processing capability is the sub CPU.

  The multifunction machine 10 includes a main CPU 11, a sub CPU 12, a ROM (Read Only Memory) 13, a RAM (Random Access Memory) 14, a nonvolatile memory 15, a hard disk device 16, a display unit 17, and an operation unit 18. A facsimile communication unit 19, a network control unit 20, a network I / F (Interface) 21, an image processing unit 22, a scanner unit 23, and a printer unit 24 are connected to a bus 25. The power supply unit 26 is configured to supply power. A network 2 based on a LAN (Local Area Network) is connected to the network I / F 21.

  The main CPU 11 controls the operation of the multifunction machine 10 based on a program stored in the ROM 13.

  The sub CPU 12 detects disconnection of the network 2 in the multifunction machine 10 based on a program stored in the ROM 13. When the network is a LAN, if the network 2 is disconnected because the network cable connected to the multifunction machine 10 is disconnected or the like, a link down notification that cannot establish communication in the data link layer (second layer) is sent to the network. It is sent to the network control unit 20 via the I / F 21. The sub CPU 12 detects the disconnection of the network 2 in the multifunction device 10 by checking whether or not the link down notification is sent to the network control unit 20.

  The ROM 13 stores programs executed by the main CPU 11 and the sub CPU 12. The RAM 14 is used as a work memory for temporarily storing various data when the main CPU 11 and the sub CPU 12 execute programs, and is also used for an image memory for temporarily storing image data.

  The nonvolatile memory 15 is a memory that retains memory even when the power is turned off, and stores device-specific information and various setting information. The hard disk device 16 stores various types of saved data and also saves input image data and the like.

  The display unit 17 is configured by a liquid crystal display or the like, and displays various screens such as an operation screen, a setting screen, and a guidance screen. The operation unit 18 includes various buttons such as a start button, a stop button, and a numeric keypad, and a touch panel that is provided on the surface of the liquid crystal display and detects a pressed coordinate position. Accepts various operations to be performed.

  The facsimile communication unit 19 transmits / receives image data to / from an external apparatus having a facsimile function through a public line. The network control unit 20 controls the network I / F 21 to enable / disable the communication function.

  When the communication function is enabled, the network I / F 21 connects to the network 2 (establishment of communication), and communicates with a terminal device, a server, and the like through the network 2. When the communication function is invalidated, the connection with the network 2 is disconnected (blocked). When the network 2 is disconnected due to disconnection of the network cable or the like, a link down notification indicating that communication cannot be established is transmitted to the network control unit 20.

  The image processing unit 22 performs various kinds of image processing such as image correction, rotation, enlargement / reduction, compression / expansion on the image data.

  The scanner unit 23 optically reads a document and acquires image data. The scanner unit 23 sequentially moves, for example, a light source that irradiates light on a document, a line image sensor that receives the reflected light for one line in the width direction, and a line-by-line reading position in the length direction of the document. An optical path composed of a lens, a mirror and the like for guiding the reflected light from the document to the line image sensor to form an image, a conversion unit for converting the analog image signal output from the line image sensor into digital image data, etc. It is configured with.

  The printer unit 24 forms and outputs an image based on the image data on a recording sheet by an electrophotographic process. The printer unit 24 includes, for example, a recording paper conveyance device, a photosensitive drum, a charging device, an LD (Laser Diode) that is controlled to be turned on according to input image data, and laser light emitted from the LD. It is configured as a so-called laser printer having a scanning unit that scans on a photosensitive drum, a developing device, a transfer separating device, a cleaning device, and a fixing device. Instead of an LED printer that irradiates a photosensitive drum with an LED (Light Emitting Diode) instead of a laser beam, other types of printers may be used.

  The power source unit 26 includes a main power source and a sub power source, and supplies power to each of the above units. The location where power is supplied from the power supply unit 26 is switched according to the on / off state of the power supply (sub power supply) of the multifunction device 10 and the operation mode of the multifunction device 10.

  The multi-function device 10 includes a main power switch that accepts an on / off operation of the main power source and a sub power switch that accepts an on / off operation of the sub power source. The main power switch is normally turned on at all times, and is turned off when the inside of the multifunction device 10 is inspected or the outlet of the multifunction device 10 is unplugged. The sub power switch is a switch for switching between normal power-on (power-on state) for turning on the multifunction device 10 and normal power-off (power-off state) for turning off the multifunction device 10.

  In addition, the multifunction device 10 supplies power to each unit from the power supply unit 26 when the sub power switch is turned on, and performs normal operation in a state where all functions can be used. The power supply unit 26 includes a power saving mode (power saving operation mode) that suppresses or stops the supply of power from the power supply unit 26 to stop a predetermined function and suppresses power consumption.

  For example, when the MFP 10 is in a normal operation mode and no operation is continued for a predetermined time, or when a print job or facsimile is not received for a predetermined time, the MFP 10 switches from the normal operation mode to the power saving mode. Migrate automatically. Further, when an operation is received in the power saving mode or a reception request for a print job or facsimile is received, the power saving mode is automatically shifted (returned) to the normal operation mode. The power saving mode includes, for example, a plurality of modes (standby mode, sleep mode, etc.) in which the contents of power supply control (power supply suppression / stop control) differ depending on the function to be stopped.

  The main CPU 11 performs power supply control for itself and power supply control for the display unit 17, the operation unit 18, the hard disk device 16, the facsimile communication unit 19, the image processing unit 22, the scanner unit 23, and the printer unit 24.

  In the normal operation mode in the power-on state, the main CPU 11 causes the power supply unit 26 to supply power to itself and each of the above-described units, and operates itself and the above-described units normally. In this normal operation mode, the main CPU 11 is in an operating state.

  In the power saving mode in the power-on state, the main CPU 11 suppresses / stops the supply of power from the power supply unit 26 to itself and the above-described units, and suppresses / stops the operations of itself and the above-described units. For example, the power supply to the display unit 17, the hard disk device 16, the image processing unit 22, and the printer unit 24 is stopped to stop the operation. Supply of electric power to the operation unit 18 is suppressed, and when the operation unit 18 receives an operation, the operation unit 18 is stopped in addition to the function of detecting that and notifying the main CPU 11 of the operation. In addition to the function of suppressing power supply to the facsimile communication unit 19 and detecting the fact when the facsimile communication unit 19 receives a facsimile reception request and notifying the main CPU 11, the operation of the facsimile communication unit 19 Stop. Supply of power to the scanner unit 23 is suppressed, and the operation of the scanner unit 23 is stopped in addition to the function of the scanner unit 23 detecting and notifying the main CPU 11 when a document is set. The power supply to the self is suppressed, and when the above notification is received from the operation unit 18, the facsimile communication unit 19, and the scanner unit 23, the network I / F 21 receives a print job reception request and In addition to the function of returning the multifunction machine 10 from the power saving mode to the normal operation mode in response to the notification, the operation is stopped. In this power saving mode, the main CPU 11 is substantially inactive.

  In the power-off state, the supply of power from the power supply unit 26 to the above-described units and the above-described units is stopped, and the operation of the self-units and the above-described units is stopped. In this power-off state, the main CPU 11 is in a non-operating state.

  The sub CPU 12, ROM 13, RAM 14, nonvolatile memory 15, network control unit 20, and network I / F 21 are not subjected to power supply control by the main CPU 11, and are in a power-on state (normal operation mode / power saving mode). Regardless of the power-off state, the power supply unit 26 receives power and operates.

  In the MFP 10 of this embodiment, even when the main CPU 11 is in the power-off state or the power saving mode and the main CPU 11 is not operating, the sub CPU 12 and each of the above units are continuously supplied with power and the sub CPU 12 is connected to the network 2. It is the structure which detects disconnection of.

  Next, the operation of the multifunction machine 10 will be described.

  FIG. 2 is a flowchart showing an operation of detecting a network disconnection by the sub CPU 12. FIG. 2 shows an operation when the sub CPU 12 detects a network disconnection regardless of whether the main CPU 11 is in an operating state or a non-operating state.

  The sub CPU 12 checks whether or not the network control unit 20 receives a link down notification from the network I / F 21 (step S101), and monitors the occurrence of a link down state (step S102; No). When the network 2 is disconnected because the network cable connected to the multifunction device 10 is disconnected or the like, a link down notification is sent from the network I / F 21 to the network control unit 20. When the sub CPU 12 confirms that the network control unit 20 has received the link down notification, the sub CPU 12 determines that a link down state has occurred (step S102; Yes), and detects the disconnection of the network 2 in the multifunction machine 10 (step S103). .

  The sub CPU 12 checks whether or not the main CPU 11 is operating, and if the main CPU 11 is operating (step S104; Yes), notifies the main CPU 11 of a network disconnection (step S106 / End). When the main CPU 11 is not operating (step S104; No), the sub CPU 12 stores information indicating the network disconnection in the nonvolatile memory 15 (or RAM 14), and monitors whether the main CPU 11 receives an operation start notification. (Step S105; No). When the operation start notification is received from the main CPU 11 (step S105; Yes), the information stored in the nonvolatile memory 15 is read and erased, and the network disconnection is notified to the main CPU 11 (step S106 / End).

  FIG. 3 is a diagram showing a flow of normal operation (operation in the normal operation mode) by the main CPU 11.

  When the main CPU 11 starts an operation to activate the multifunction device 10 in response to an ON operation of the sub power switch, or starts an operation to return the multifunction device 10 from the power saving mode to the normal operation mode, the sub CPU 12 Is notified of the start of operation (step S301). When the main CPU 11 does not receive a network disconnection notification (response) from the sub CPU 12 (step S302; No), the main CPU 11 operates the multi-function device 10 in the normal operation mode (step S304). When a notification of network disconnection is received from the sub CPU 12 (step S302; Yes), a warning screen is displayed on the display unit 17 (step S303).

  FIG. 4 is a diagram illustrating an example of a warning screen 50 displayed on the display unit 17 during activation of the multifunction machine 10. On the warning screen 50, information 51 to be transmitted to the user and an OK button 52 for receiving a confirmation (acceptance) operation on the information 51 from the user are displayed. The information 51 is information describing in text that it is recommended to check the network (network cable or the like) to which this machine (multifunction machine 10) is connected because a disconnection of the network is detected. Note that similar information and an OK button are also displayed on the warning screen displayed when returning from the power saving mode to the normal operation mode.

  When the OK button in the warning screen is pressed, the main CPU 11 deletes the display of the warning screen and operates the multifunction machine 10 in the normal operation mode (step S304).

  When the main CPU 11 operates the MFP 10 in the normal operation mode and receives a network disconnection notification from the sub CPU 12 (step S305; Yes), the main CPU 11 displays a warning screen on the display unit 17 (step S303). ). Information similar to the warning screen 50 of FIG. 4 and an OK button are also displayed on the warning screen displayed when operating in the normal operation mode.

  When the OK button in the warning screen is pressed, the main CPU 11 deletes the display of the warning screen and operates the multifunction machine 10 in the normal operation mode (step S304). When the network disconnection notification is not received from the sub CPU 12 (step S305; No), when the sub power switch is turned off, or when the MFP 10 is shifted from the normal operation mode to the power saving mode, the main CPU 11 The above-described power supply control (power supply suppression / stop control) is performed to stop its own operation (End).

  FIG. 5 is a flowchart showing a modification of the operation for detecting network disconnection by the sub CPU 12. FIG. 5 shows an operation when the main CPU 11 detects a network disconnection when the main CPU 11 is in an operating state and the sub CPU 12 detects a network disconnection when the main CPU 11 is in a non-operating state.

  The sub CPU 12 checks the operation status of the main CPU 11 (step S201). If the sub CPU 12 confirms that the main CPU 11 is operating (step S202; Yes), the operation status of the main CPU 11 is not detected without detecting network disconnection. Continue checking. When it is confirmed that the main CPU 11 is not operating (step S202; No), network disconnection detection is started (step S203 / to FIG. 2). Further, when the sub CPU 12 does not detect the network disconnection while the main CPU 11 is not operating and receives a notification of the operation start from the main CPU 11, the sub CPU 12 stops the network disconnection detection.

  The operation of the main CPU 11 corresponding to FIG. 5 (and FIG. 2) is an operation in which the main CPU 11 detects a network disconnection in step S305 of FIG. In this case, the main CPU 11 checks whether or not the network control unit 20 receives a link down notification from the network I / F 21 when the MFP 10 is operating in the normal operation mode, and generates a link down state. Monitor. When the main CPU 11 confirms that the network control unit 20 has received the link-down notification, the main CPU 11 determines that a link-down state has occurred, detects a disconnection of the network 2 in the multifunction device 10, and displays a warning screen on the display unit 17. .

  As described above, in the MFP 10 according to the present embodiment, the sub CPU 12 detects the disconnection of the network 2 in the network I / F 21 when the main CPU 11 that controls the operation of the MFP 10 is not operating. Specifically, the sub CPU 12 monitors the disconnection of the network 2 in the network I / F 21 even when the main CPU 11 is not operating in the power-off state or the power saving mode of the multifunction machine 10. As a result, it is possible to ensure security against unauthorized disconnection and connection of the network 2 when the main CPU 11 is not operating.

  Particularly in this embodiment, when the sub CPU 12 detects a disconnection of the network 2 when the main CPU 11 is not operating, the sub CPU 12 notifies the main CPU 11 that the disconnection of the network 2 has been detected when the main CPU 11 starts operating. . Upon receiving this notification, the main CPU 11 displays a warning screen to notify the user that a network disconnection has been detected. The user can take a response such as checking the network cable connected to the network I / F 21 of the multifunction machine 10 by checking the warning screen to know that the network is disconnected.

[Second Embodiment]
In the second embodiment, a case where the communication operation of the network I / F 21 is stopped when the sub CPU 12 detects disconnection of the network 2 will be described.

  FIG. 6 is a flowchart showing an operation of detecting a network disconnection by the sub CPU 12 according to the second embodiment. FIG. 6 shows an operation when the sub CPU 12 detects a network disconnection regardless of whether the main CPU 11 is in an operating state or a non-operating state.

  The sub CPU 12 checks whether or not the network control unit 20 receives a link down notification from the network I / F 21 (step S401), and monitors the occurrence of a link down state (step S402; No). When the network 2 is disconnected because the network cable connected to the multifunction device 10 is disconnected or the like, a link down notification is sent from the network I / F 21 to the network control unit 20. When the sub CPU 12 confirms that the network control unit 20 has received the link down notification, the sub CPU 12 determines that a link down state has occurred (step S402; Yes (network disconnection detection)), and notifies the network control unit 20 of the network I / F 21. Request to disable the communication function. Upon receiving this request from the sub CPU 12, the network control unit 20 invalidates the communication function of the network I / F 21 (network disconnection (blocking) state).

  The sub CPU 12 checks whether or not the main CPU 11 is operating, and if the main CPU 11 is operating (step S404; Yes), notifies the main CPU 11 of a network disconnection (step S406 / End). When the main CPU 11 is not operating (step S404; No), the sub CPU 12 stores information indicating the network disconnection in the nonvolatile memory 15 (or the RAM 14), and monitors whether or not the main CPU 11 receives an operation start notification. (Step S405; No). When the operation start notification is received from the main CPU 11 (step S405; Yes), the information stored in the nonvolatile memory 15 is read and erased, and the network disconnection is notified to the main CPU 11 (step S406 / End).

  FIG. 7 is a diagram illustrating a flow of normal operation (operation in the normal operation mode) by the main CPU 11 according to the second embodiment.

  When the main CPU 11 starts an operation to activate the multifunction device 10 in response to an ON operation of the sub power switch, or starts an operation to return the multifunction device 10 from the power saving mode to the normal operation mode, the sub CPU 12 Is notified of the start of operation (step S501). When the main CPU 11 does not receive a network disconnection notification (reply) from the sub CPU 12 (step S502; No), the main CPU 11 operates the multifunction peripheral 10 in the normal operation mode (step S507). When a notification of network disconnection is received from the sub CPU 12 (step S502; Yes), a password input screen is displayed on the display unit 17 (step S503).

  FIG. 8 is a diagram illustrating an example of the password input screen 60 displayed on the display unit 17 while the multifunction device 10 is activated. The password input screen 60 includes information 61 to be transmitted to the user, a password display field 62 in which the password input through the operation unit 18 is displayed, and an OK button for accepting a confirmation (OK) operation from the user for the input password. 63 and a cancel button 64 for accepting a cancel operation from the user for the input password. The information 61 is information describing in text that a communication function is restricted because a disconnection of the network is detected, and that a password must be input to remove this restriction. Similar information, a password display field, an OK button, and a cancel button are also displayed on the password input screen that is displayed when returning from the power saving mode to the normal operation mode.

  When the password input through the password input screen is not correct (step S504; No), the main CPU 11 continues the invalid state of the network communication function (step S505) and continues displaying the password input screen (step S503). . If the password entered through the password entry screen is correct (step S504; Yes), the password entry screen display is cleared, the network communication function is enabled (step S506), and the MFP 10 is operated in the normal operation mode. (Step S507). Specifically, the main CPU 11 requests the network control unit 20 to validate the communication function of the network I / F 21. Upon receiving this request from the main CPU 11, the network control unit 20 enables the communication function of the network I / F 21 (network connection state).

  When the main CPU 11 receives the network disconnection notification from the sub CPU 12 while operating the MFP 10 in the normal operation mode (step S508; Yes), the main CPU 11 displays a password input screen on the display unit 17 (step S508). S503). Information similar to the password input screen 60 shown in FIG. 8, a password display field, an OK button, and a cancel button are also displayed on the password input screen displayed when operating in the normal operation mode.

  When the password input through the password input screen is not correct (step S504; No), the main CPU 11 continues the network communication function invalid state (step S505) and continues displaying the password input screen 60 (step S503). ). If the password entered through the password entry screen is correct (step S504; Yes), the password entry screen display is cleared, the network communication function is enabled (step S506), and the MFP 10 is operated in the normal operation mode. (Step S507). When the sub-CPU 12 does not receive a network disconnection notification (step S508; No) and receives a sub-power switch OFF operation, or when the MFP 10 is shifted from the normal operation mode to the power saving mode, the main CPU 11 The above-described power supply control (power supply suppression / stop control) is performed to stop its own operation (End).

  As described above, in the second embodiment, when the sub CPU 12 detects disconnection of the network 2 in the network I / F 21, the sub CPU 12 stops the communication operation of the network I / F 21. Thereby, for example, even when the network connected to the network I / F 21 is illegally switched to another network when the main CPU 11 is not operating, the communication between the network and the multifunction peripheral 10 (network I / F 21) is performed. Is blocked, and the MFP 10 can be prevented from being attacked through the network. Similarly, when the network connected to the network I / F 21 is illegally switched to another network during the operation of the main CPU 11, the communication operation of the network I / F 21 is detected when the sub CPU 12 detects disconnection of the network. Therefore, communication between the reconnected network and the multifunction device 10 (network I / F 21) is blocked, and the multifunction device 10 can be prevented from being attacked through the network.

  Particularly in this embodiment, when the sub CPU 12 detects a disconnection of the network 2 when the main CPU 11 is not operating, the sub CPU 12 notifies the main CPU 11 that the disconnection of the network 2 has been detected when the main CPU 11 starts operating. . Upon receiving this notification, the main CPU 11 displays a password input screen (network connection screen), notifies the user that a disconnection of the network has been detected, and accepts a password input for releasing the restriction on the network communication function. Thereby, the user can cancel the restriction of the network communication function (stop of the communication operation of the network I / F 21) by inputting the correct password through the password input screen 60.

  The embodiment of the present invention has been described with reference to the drawings. However, the specific configuration is not limited to that shown in the embodiment, and the present invention can be changed or added without departing from the scope of the present invention. Included in the invention.

  For example, the modification example of the network disconnection detection operation by the sub CPU 12 described in FIG. 5 in the first embodiment can be combined with the network disconnection detection operation (FIG. 6) by the sub CPU 12 in the second embodiment. The operation of the main CPU 11 corresponding to this is an operation in which the main CPU 11 detects a network disconnection in step S508 of FIG.

  In this case, the main CPU 11 checks whether or not the network control unit 20 receives a link down notification from the network I / F 21 when the MFP 10 is operating in the normal operation mode, and generates a link down state. Monitor. When the main CPU 11 confirms that the network control unit 20 has received the link-down notification, the main CPU 11 determines that a link-down state has occurred, detects a disconnection of the network 2 in the multifunction machine 10, and displays a password input screen on the display unit 17. To do.

  In addition, the image forming apparatus according to the present invention is not limited to the multi-function apparatus described in the embodiment, and other image forming apparatuses such as a copying machine, a printer, and a facsimile machine can be targeted. The network device according to the present invention is not limited to the network device provided in the image forming apparatus, but can be applied to various information equipment devices having a network communication function.

2 ... Network 10 ... Multifunction machine 11 ... Main CPU
12 ... Sub CPU
13 ... ROM
14 ... RAM
DESCRIPTION OF SYMBOLS 15 ... Nonvolatile memory 16 ... Hard disk device 17 ... Display part 18 ... Operation part 19 ... Facsimile communication part 20 ... Network control part 21 ... Network I / F
DESCRIPTION OF SYMBOLS 22 ... Image processing part 23 ... Scanner part 24 ... Printer part 25 ... Bus 26 ... Power supply part 50 ... Warning screen 51 ... Information 52 ... OK button 60 ... Password input screen 61 ... Information 62 ... Password display column 63 ... OK button 64 ... Cancel button

Claims (7)

A first CPU for controlling the operation of the network device;
A network interface unit that communicates with an external device through a network;
A second CPU that detects disconnection of the network in the network interface unit when the first CPU is not operating;
A network device comprising: The network device according to claim 1, wherein the second CPU detects a disconnection of the network in the network interface unit even when the first CPU operates. The network device according to claim 1, wherein the second CPU stops communication operation of the network interface unit when detecting disconnection of the network. 2. When the disconnection of the network is detected, the second CPU notifies the first CPU that the disconnection of the network is detected when the first CPU operates. 2. The network apparatus of any one of -3. The network device according to claim 4, wherein the first CPU notifies the user that a disconnection of the network has been detected when the notification is received. When the second CPU stops the communication operation of the network interface unit, the second CPU notifies the first CPU that the disconnection of the network has been detected during the operation of the first CPU.
The first CPU displays a network connection screen when receiving the notification, and cancels the stop of the communication operation of the network interface unit when receiving a predetermined operation through the network connection screen. 4. The network device according to 3. The network device according to any one of claims 1 to 6,
An image forming unit that is controlled by the first CPU to form an image based on image data on a recording sheet;
An image forming apparatus comprising:

Images