Patent Publication Number: US-2013250355-A1

Title: Image forming apparatus, address setting method, and storage medium storing program

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an image forming apparatus for setting a MAC address, an address setting method, and a storage medium storing a program. 
     2. Description of the Related Art 
     When an image forming apparatus such as a printer equipped with a network interface is used across a network, a DHCP or the like allocates an IP address to the MAC address of the apparatus. An information processing apparatus such as a PC that controls the image forming apparatus can track the dynamically changeable IP address of the image forming apparatus based on the MAC address. Therefore, even when the IP address changes because the image forming apparatus is restarted or the effective period of the IP address has expired, the information processing apparatus can automatically track the IP address of the image forming apparatus. 
     As wireless network apparatuses increase in number in recent years, many image forming apparatuses include a plurality of network interfaces such as a wired network interface and wireless network interface. In an image forming apparatus like this, the network interfaces are switched in some cases. An example is a case in which the image information apparatus is initialized by using the wired network interface but operated by using the wireless network interface after that. Another example is a case in which an error occurs in a wireless access point while the image forming apparatus is operated by using the wireless network interface and the apparatus is kept operated by switching to the wired network interface. A still another example is a case in which the form of connection to a network is physically changed by changing the installation location of the image forming apparatus. 
     The plurality of network interfaces of the image forming apparatus have unique MAC addresses, respectively. If the network interfaces are switched as described above, therefore, the MAC addresses also change. Accordingly, an external apparatus cannot track the IP address of the image forming apparatus based on its MAC address, and cannot communicate with the image forming apparatus any longer. 
     Japanese Patent Laid-Open No. 2002-51068 describes that two network apparatuses are duplicated as one set and one of their MAC addresses is determined as a system MAC address. Japanese Patent Laid-Open No. 2002-51068 describes that an external apparatus can seamlessly access the two network apparatuses because the system MAC address is used when the external apparatus communicates with the network apparatuses. 
     In Japanese Patent Laid-Open No. 2002-51068, however, one of the MAC addresses of the two apparatuses is determined as the system MAC address. Therefore, if the MAC address of at least one of the apparatuses changes, the system MAC address also changes, so communication with an external apparatus cannot be continued. 
     SUMMARY OF THE INVENTION 
     An aspect of the present invention is to eliminate the above-mentioned problems with the conventional technology. The present invention provides an image forming apparatus that uniquely sets a MAC address for tracking an IP address, an address setting method, and a storage medium storing a program. 
     The present invention in its first aspect provides an image forming apparatus capable of handling a plurality of MAC addresses, comprising: a setting unit configured to set a MAC address of the plurality of MAC addresses to which an IP address is to be allocated, and key data for tracking an IP address corresponding to the image forming apparatus; and a notification unit configured to notify an external apparatus of the MAC address and the key data set by the setting unit. 
     The present invention in its second aspect provides an address setting method to be executed in an image forming apparatus having a plurality of MAC addresses, comprising: a setting step of setting a MAC address of the plurality of MAC addresses to which an IP address is to be allocated, and key data for tracking an IP address corresponding to the image forming apparatus; and a notification step of notifying an external apparatus of the MAC address and the key data set in the setting step. 
     The present invention in its third aspect provides a computer-readable storage medium storing a program for causing a computer to execute an address setting method to be executed in an image forming apparatus having a plurality of MAC addresses, the method comprising: a setting step of setting a MAC address of the plurality of MAC addresses to which an IP address is to be allocated, and key data for tracking an IP address corresponding to the image forming apparatus; and a notification step of notifying an external apparatus of the MAC address and the key data set in the setting step. 
     In the present invention, a MAC address for tracking an IP address can uniquely be set. 
     Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a block diagram showing the hardware configuration of an image forming apparatus; 
         FIGS. 2A and 2B  are views for explaining the notification of the key MAC address of the image forming apparatus; 
         FIG. 3  is a flowchart showing the procedure of an IP address automatic tracking process; and 
         FIG. 4  is a flowchart showing the procedure of a key MAC address selecting process. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     Preferred embodiments of the present invention will now be described hereinafter in detail, with reference to the accompanying drawings. It is to be understood that the following embodiments are not intended to limit the claims of the present invention, and that not all of the combinations of the aspects that are described according to the following embodiments are necessarily required with respect to the means to solve the problems according to the present invention. Note that the same reference numerals denote the same constituent elements, and a repetitive explanation thereof will be omitted. 
     First Embodiment  
       FIG. 1  is a block diagram showing the hardware configuration of an image forming apparatus  100  of an embodiment according to the present invention. Referring to  FIG. 1 , arrows between blocks indicate the flows of data or instructions. In this embodiment, a process by which the image forming apparatus sets a unique MAC address for a dynamically changeable IP address will be described by taking, as an example, a case in which a PC tracks the IP address of a printer (the image forming apparatus) connected to the PC. However, this process may also be executed on, for example, a PC managed by a server, instead of the image forming apparatus. In the following description, both the image forming apparatus and PC will also generically be referred to as communicating apparatuses. 
     The image forming apparatus  100  includes a printer  107 , a scanner  109 , an operation panel  110 , a line interface (I/F)  112 , and a controller  101  for controlling them. The controller  101  includes a CPU  102 , RAM  103 , ROM  104 , printer I/F  106 , scanner I/F  108 , MODEM  111 , and network I/Fs  115  and  118 . Also, these blocks are connected via a system bus  105  so that they can communicate with each other. 
     The CPU  102  comprehensively controls the above-mentioned blocks in accordance with various control programs. The CPU  102  reads out and executes a control program stored in a program area of the ROM  104 . Alternatively, the CPU  102  executes compressed data stored in the program area of the ROM  104  by decompressing and expanding the data into the RAM  103 . The various control programs may also be stored in a compressed/uncompressed state in a hard disk drive (HDD) (not shown). The network I/Fs  115  and  118  connect the image forming apparatus  100  to a network (LAN)  120 . With this arrangement, the CPU  102  can communicate with a host computer (PC)  121  across the network  120 . The image forming apparatus  100  can connect to a wired network  116  and wireless network by using the network I/Fs  115  and  118  and network  120 . It is possible to use, for example, a LAN cable as the wired network  116 , and use, for example, a wireless LAN as a wireless network  119 . The MODEM  111  is connected to a public network  114  via the line I/F  112 . With this arrangement, the CPU  102  can communicate with, for example, another image forming apparatus, a facsimile apparatus, or a telephone set (none of them is shown). The line I/F  112  and public network  114  are connected by a telephone line  113  or the like. 
     The printer I/F  106  functions as an interface for outputting an image signal to the printer  107  (a printer engine). The scanner I/F  108  functions as an interface for receiving a scanned image signal from the scanner  109  (a scanner engine). With this arrangement, the CPU  102  can process an input image signal from the scanner I/F  108 , and output the processed image signal as a printing image signal to the printer I/F  106 . The CPU  102  displays characters and symbols on a display unit of the operation panel  110  by using font information stored in a font area (font ROM) of the ROM  104 , and accepts instructions from the user via the operation panel  110 . Also, the CPU  102  stores, for example, apparatus information of the image forming apparatus  100 , user&#39;s telephone directory information, and department management information in a data area (data ROM) of the ROM  104 , and reads out and updates these pieces of information as needed. Although the scanner  109  and printer  107  are formed inside the image forming apparatus  100  in  FIG. 1 , one or both of these units may also be formed outside. 
       FIGS. 2A and 2B  are views for explaining the notification of a key MAC address in this embodiment. The image forming apparatus  100  physically includes the network interfaces  115  and  118 . For example, the network interface  115  is a wired network interface, and the network interface  118  is a wireless network interface. Also, the network interface  115  has a MAC address “xx-xx-xx-xx-xx-01”, and the network interface  118  has a MAC address “xx-xx-xx-xx-xx-02”. Assume that a DHCP (Dynamic Host Configuration Protocol) allocates an IP address “192.168.0.1” when using the network interface  115 . Assume also that the DHCP allocates an IP address “192.168.0.2” when using the network interface  118 . 
     For example, the PC  121  installs a printer driver corresponding to the image forming apparatus  100  as a printer. In this case, the PC  121  inquires of the image forming apparatus  100  about information necessary to communicate with the image forming apparatus  100 . The necessary information herein mentioned includes the MAC address of a presently effective network interface of the image forming apparatus  100 , an IP address allocated to the MAC address, and a key MAC address. The key MAC address is a MAC address required for the PC  121  to track the IP address of the image forming apparatus  100  in  FIGS. 1 ,  2 A, and  2 B. That is, the key MAC address is a MAC address that functions as a key. When the image forming apparatus  100  includes a plurality of network interfaces, the MAC address of one of these network interfaces can be set as the key MAC address. 
     The notification of the key MAC address of the image forming apparatus  100  will be explained below with reference to  FIGS. 2A and 2B . First, assume that the presently effective network interface of the image forming apparatus  100  is the network interface  115 . Second, assume that the image forming apparatus  100  has set the MAC address of the network interface  115  as the key MAC address. 
     The PC  121  shown in  FIG. 2A  inquires of the image forming apparatus  100  about information necessary to communicate with the image forming apparatus  100 . The image forming apparatus  100  notifies the PC  121  of the MAC address “xx-xx-xx-xx-xx-01” of the network interface  115 , the IP address “192.168.0.1”, and the key MAC address “xx-xx-xx-xx-xx-01”. After that, the PC  121  can communicate with the image forming apparatus  100  by forming a port by using the key MAC address and IP address notified from the image forming apparatus  100 . 
     Assume that the image forming apparatus  100  switches from the network interface  115  to the network interface  118  in this state. This is equivalent to a case in which the image forming apparatus  100  switches from the connection to the wired network to the connection to the wireless network. Assume that the PC  121  installs the printer driver of the image forming apparatus  100  and inquires of the image forming apparatus  100  about information necessary to communicate with it. As shown in  FIG. 2B , the image forming apparatus  100  notifies the PC  121  of the MAC address “xx-xx-xx-xx-xx-02” of the network interface  118 , the IP address “192.168.0.2”, and the key MAC address “xx-xx-xx-xx-xx-01”. After that, the PC  121  can communicate with the image forming apparatus  100  by forming a port by using the key MAC address and IP address notified from the image forming apparatus  100 . 
     In this embodiment as described above, even when the image forming apparatus  100  has a plurality of MAC addresses, an external apparatus is notified of a MAC address always unique to the IP address in order to track it. With this arrangement, the external apparatus (PC  121 ) can reliably track the dynamically changeable IP address by using a DHCP or the like, based on the key MAC address notified from the image forming apparatus  100 . 
       FIG. 3  is a view showing the procedure of an IP address automatic tracking process in this embodiment. Processing on the side of the PC  121  shown in  FIG. 3  is executed by, for example, the CPU of the PC  121 . Also, processing on the side of the image forming apparatus  100  shown in  FIG. 3  is executed by, for example, the CPU  102  of the image forming apparatus  100 . 
     First, in step S 301 , the CPU of the PC  121  installs the driver of the image forming apparatus  100  in the PC  121 . This driver is, for example, a printer driver. This processing in step S 301  allows the PC  121  to use a function (for example, a printer function) of the image forming apparatus  100 . In step S 302 , the CPU of the PC  121  inquires of the image forming apparatus  100  about apparatus basic information for communicating with the image forming apparatus  100  across the network  120 . This is equivalent to the processing explained above with reference to  FIGS. 2A and 2B . The apparatus basic information includes the MAC address (also called the device MAC address) of a presently effective network interface of the image forming apparatus  100 , the above-mentioned key MAC address, and a presently allocated IP address. 
     In step S 303 , the CPU of the PC  121  transmits, to the image forming apparatus  100 , a request packet for requesting the aforementioned apparatus basic information. In step S 304 , the CPU  102  of the image forming apparatus  100  notifies the PC  121  of the MAC address of the presently effective network interface, the key MAC address (key data), and the IP address presently allocated to the image forming apparatus  100 . In step S 305 , the CPU of the PC  121  forms a port for communicating with the image forming apparatus  100  across the network  120 , by using the apparatus basic information obtained from the image forming apparatus  100 . In this embodiment, the MAC address of the presently effective network interface is “xx-xx-xx-xx-xx-01”, the key MAC address of the image forming apparatus  100  is “xx-xx-xx-xx-xx-01”, and the IP address presently allocated to the image forming apparatus  100  is “192.168.0.1”. 
     After forming the port in step S 305 , the CPU of the PC  121  transmits request packets (broadcast packets) to the image forming apparatus  100  at a predetermined arbitrary time interval in steps S 306  and S 309 , in order to detect (track) the change in IP address. More specifically, the CPU of the PC  121  transmits request packets in steps S 307  and S 310  based on the key MAC address obtained in step S 302 , thereby requesting the notification of the IP address. In steps S 308  and S 311 , the CPU  102  of the image forming apparatus  100  having the requested key MAC address notifies the PC  121  of the key MAC address and presently allocated IP address in response to the requests in steps S 307  and S 310 . 
     Assume that the image forming apparatus  100  having the key MAC address “xx-xx-xx-xx-xx-01” is restarted by a user&#39;s operation or the like in step S 312 . In this embodiment, an IP address automatically obtained by the DHCP or the like upon restart is changed to “192.168.0.2”. 
     In step S 313 , the CPU of the PC  121  transmits request packets to the image forming apparatus  100  at a predetermined arbitrary time interval in order to detect the change in IP address, as in steps S 306  and S 309 . More specifically, in step S 314 , the CPU of the PC  121  transmits a request packet based on the key MAC address obtained in step S 302 , thereby requesting the notification of the IP address. In step S 315 , the CPU  102  of the image forming apparatus  100  having the requested key MAC address notifies the PC  121  of the key MAC address and the presently allocated IP address “192.168.0.2”, in response to the request in step S 314 . 
     Assume that the network interfaces of the image forming apparatus  100  having the key MAC address “xx-xx-xx-xx-xx-01” are switched in step S 316 . This is a case in which the user changes the connections of the image forming apparatus  100  from the wired network to the wireless network. In this embodiment, the IP address is further changed to “192.168.0.3” when the network interfaces are switched. 
     In step S 317 , the CPU of the PC  121  transmits request packets to the image forming apparatus  100  at a predetermined arbitrary time interval in order to detect the change in IP address, as in steps S 306  and S 309 . More specifically, in step S 318 , the CPU of the PC  121  transmits a request packet based on the key MAC address obtained in step S 302 , thereby requesting the notification of the IP address. In step S 319 , the CPU  102  of the image forming apparatus  100  having the requested key MAC address notifies the PC  121  of the key MAC address and the presently allocated IP address “192.168.0.3”, in response to the request in step S 318 . 
     In this embodiment as described above, the PC  121  can track the IP address without detecting the change in MAC address of the image forming apparatus  100 . Consequently, even when the MAC address of the image forming apparatus  100  is changed, it is unnecessary to obtain the apparatus basic information by installing the driver of the image forming apparatus  100 . 
     Second Embodiment  
     In the first embodiment, the key MAC address is fixedly set as the MAC address of a given network interface of the image forming apparatus  100 . In this embodiment, when the image forming apparatus  100  includes a plurality of network interfaces, the MAC address of a network interface designated by the user is set as the key MAC address. 
       FIG. 4  is a flowchart showing the procedure of key MAC address setting in this embodiment. This process shown in  FIG. 4  is executed by, for example, the CPU  102  of the image forming apparatus  100 . In step S 401 , the CPU  102  determines whether a plurality of network interfaces are installed in the image forming apparatus  100 . If it is determined that only one network interface is installed, the CPU  102  sets the MAC address (device MAC address) of the network interface as the key MAC address in step S 402 , and terminates the process shown in  FIG. 4 . 
     On the other hand, if it is determined that a plurality of network interfaces are installed, the process advances to step S 403 , and the CPU  102  allows the user to select a network interface whose MAC address is to be used as the key MAC address. In this step, the CPU  102  causes the operation panel  110  to display a list of the MAC addresses of the network interfaces as a selection screen, and accepts a user&#39;s selection on the selection screen as the key MAC address. Then, the CPU  102  determines whether a user&#39;s selection is accepted. 
     If it is determined that a user&#39;s selection is accepted, the CPU  102  sets the MAC address of the network interface selected by the user as the key MAC address in step S 404 . On the other hand, if it is determined that no user&#39;s selection is accepted, the process advances to step S 405 , and the CPU  102  selects a preset default MAC address as the key MAC address. For example, if the user has not selected the MAC address of any network interface, the MAC address of one of the network interfaces is selected as the key MAC address. 
     Other Embodiments  
     Aspects of the present invention can also be realized by a computer of a system or apparatus (or devices such as a CPU or MPU) that reads out and executes a program recorded on a memory device to perform the functions of the above-described embodiment(s), and by a method, the steps of which are performed by a computer of a system or apparatus by, for example, reading out and executing a program recorded on a memory device to perform the functions of the above-described embodiment(s). For this purpose, the program is provided to the computer for example via a network or from a recording medium of various types serving as the memory device (for example, computer-readable medium). 
     While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions. 
     This application claims the benefit of Japanese Patent Application No. 2012-067979, filed Mar. 23, 2012, which is hereby incorporated by reference herein in its entirety.