Patent Publication Number: US-2023140919-A1

Title: Image forming system using network, image control apparatus, control methods therefor, and storage media storing control programs therefor

Description:
BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to an image forming system using a network, an image control apparatus, control methods therefor, and storage media storing control programs therefor. 
     Description of the Related Art 
     A system that consists of an image control apparatus and an image forming apparatus that are connected to a network is known as a conventional image forming system. 
     The image control apparatus is used to add a network printer function to the image forming apparatus and to extend the network printer function that the image forming apparatus has beforehand. The network printer function enables to print an image corresponding to an image signal input from an external apparatus through the network. 
     For example, Japanese Laid-Open Patent Publication (Kokai) No. 2009-20810 (JP 2009-20810A) discloses an apparatus that changes a way to display available functions of an image forming apparatus on an external apparatus connected to an image control apparatus through a network depending on a connection configuration between the image control apparatus and the image forming apparatus. 
     In the conventional image forming system, the image forming apparatus communicates an external network through the image control apparatus. Accordingly, the conventional technique does not necessarily cope with all cases. For example, in the image forming system using the conventional network transfer technology (NAT/NAPT), the image forming apparatus cannot perform communication using IPv6 or IPsec. This is because the network transfer technology implemented in the image control apparatus determines that such a communication is camouflage of a network packet. 
     That is, when the image forming apparatus communicates with an external apparatus using IPv6 or IPsec, it becomes impossible to use the conventional network transfer technology (NAT/NAPT), which needs to achieve a new scheme. Particularly, since IPsec is a technique that exchanges keys between an external apparatus and an image forming apparatus and finishes communication rapidly in finding camouflage of a network packet, it is an extremely useful technique when recent network security is taken into consideration. 
     If an image forming apparatus is also connected to a network in addition to an image control apparatus, a new scheme that enables transfer of a network packet between the image forming apparatus and an external apparatus using IPv6 or IPsec can be achieved. 
     However, such a system in which the image forming system is connected to the network in addition to the image control apparatus will be inconvenient for a user. For example, when an application of the external apparatus searches the network for an available apparatus, information about an image forming apparatus that is directly connected to the network and information about an image forming apparatus that is indirectly connected to the network through the image control apparatus will be detected. However, since these two pieces of information show the same image forming apparatus actually, the user may be confused. 
     SUMMARY OF THE INVENTION 
     The present invention provides an image forming system, an image control apparatus, control methods therefor, and storage media storing control programs therefor, which are convenient for a user even when an image forming apparatus is directly connected to a network in addition to an image control apparatus. 
     Accordingly, a first aspect of the present invention provides an image forming system including an image control apparatus and an image forming apparatus. The image control apparatus includes a first communication member configured to be connected to an external apparatus through a network, a second communication member configured to be connected to an image forming apparatus through a predetermined transfer path, and a port controller configured to control switching of a predetermined network port of the first communication member. The image forming apparatus includes a third communication member configured to be connected to the external apparatus through the network, and a fourth communication member configured to be connected to the image control apparatus through the predetermined transfer path. The port controller closes the predetermined network port in a case where both of the third and fourth communication members are valid. 
     According to the present invention, the image forming system, image control apparatus, control methods therefor, and storage media storing control programs therefor, which are convenient for a user even when an image forming apparatus is directly connected to a network in addition to an image control apparatus. 
     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 schematic view showing a connection configuration of an image forming system of a first embodiment. 
         FIG.  2    is a block diagram showing a hardware configuration of a DFE shown in  FIG.  1   . 
         FIG.  3    is a block diagram showing a hardware configuration of an MFP shown in  FIG.  1   . 
         FIG.  4    is a flowchart showing a process for determining a connection configuration of the MFP of the first embodiment executed by the MFP. 
         FIG.  5    is a flowchart showing a network-port switching control process of the first embodiment executed by the DFE. 
         FIG.  6    is a flowchart showing a process for determining a connection configuration of the MFP of a second embodiment executed by the MFP. 
         FIG.  7    is a schematic view showing a connection configuration of an image forming system of a third embodiment. 
         FIG.  8    is a flowchart showing a process for determining a connection configuration of the MFP of the third embodiment executed by the MFP. 
         FIG.  9    is a flowchart showing a network-port switching control process of a fourth embodiment executed by the DFE. 
         FIG.  10    is a flowchart showing a network-port switching control process of a fifth embodiment executed by the DFE. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     Hereafter, embodiments according to the present invention will be described in detail by referring to the drawings. 
     It should be noted that the following embodiments do not restrict the invention defined by the claims and not all combinations of characteristic features described in the embodiments are indispensable to the solution of the invention. 
     First, a first embodiment will be described.  FIG.  1    is a schematic view showing a connection configuration of an image forming system  1   a  of this embodiment. 
     In the image forming system  1   a , a terminal apparatus (an external apparatus)  211 , a DFE (a Digital Front End, an image control apparatus)  201 , and an MFP (a Multi-Function Peripheral, an image forming apparatus)  207  are connected to a network  212 . Furthermore, the DFE  201  and MFP  207  are connected through a dedicated transfer path  206 . In this embodiment, a predetermined transfer path is explained as the dedicated transfer path  206 . 
     The DFE  201  is provided with connectors  202 ,  203 , and  204 . The first connector  202  (a first communication member) is an NIC connector that manages connection to the network  212  at a low layer level. The second connector  203  (a second communication member) is an interface for the dedicated transfer path  206 . The connector  204  is a connector for the dedicated transfer path through which image data is transmitted to the MFP  207  when the DFE  201  generates the image data. The connector  204  is not used in this embodiment. 
     The MFP  207  is provided with connectors  208  and  209 . The third connector  208  (a third communication member) is a connector for an NIC like Ethernet (registered trademark) that manages connection to the network  212  at the low layer level. The fourth connector  209  (a fourth communication member) is an interface for the dedicated transfer path  206 . 
     The image forming system  1   a  is characterized in that the DFE  201  and MFP  207  are connected through the dedicated transfer path  206  and that the MFP  207  is connected to the network  212 . Print data sent out to the dedicated transfer path  206  through the second connector  203  of the DFE  201  is taken into the MFP  207  through the fourth connector  209 . Moreover, the data on the network  212  is taken into the MFP  207  through the third connector  208 . 
     In addition, the fourth connector  209  may be a network interface like Ethernet (registered trademark) and may be connected to the DFE  201  through the network. Alternatively, the fourth connector  209  may be a parallel interface, a USB interface, or the like and may be directly connected to the DFE  201  through an interface cable. Moreover, a plurality of interface cables may be used. 
       FIG.  2    is a block diagram showing a hardware configuration of the DFE  201 . 
     The DFE  201  is provided with NICs  101  and  104 , an RIP processor  102 , an encoder  103 , an HDD  105 , a ROM  106 , a CPU  107 , a RAM  108 , an operation unit  109 , a display unit  110 , and an image interface board  111  in addition to the connectors  202 ,  203 , and  204 . 
     The first connector  202  is connected to the NIC  101 . The NIC  101  has a function as a first network interface to manage connection to the network  212  at the low layer level. The RIP processor  102  and HDD  105  are connected to the output side of the NIC  101 . The RIP processor  102  has an RIP processing function that rasterizes a print language like PDL or a specific format (compressed by JPEG or JBIG) and compresses it. The HDD  105  is a memory unit that temporarily stores (spools) image data received by the NIC  101  or that temporarily stores image data compressed (rasterized) by the RIP process. The ROM  106  is a memory that the RIP processor  102  uses for an image expansion process. 
     The image data that is rasterized by the RIP processor  102  is input into the encoder  103 . The encoder  103  converts the image into print data in a format or a data format supported by the MFP  207 . 
     Moreover, the DFE  201  is provided with the NIC  104  and image interface board  111 . The NIC  104  functions as a second network interface that manages connection at the low layer level. The second connector  203  is used for this interface. Moreover, the data output from the encoder  103  is output to the connector  204  through the image interface board  111  and is transferred to the MFP  207  through the dedicated transfer path  206 . 
     The CPU  107  manages control of the entire DFE  201 . 
     The RAM  108  is a memory unit that the CPU  107  uses as a data temporary storage area. 
     The operation unit  109  has buttons, keys, etc. and is used to operate the DFE  201 . 
     The display unit  110  consists of a touch panel that notifies a user of information by using an image or a character, and is constituted integrally with the operation unit  109  as an operation panel. 
     A data packet is transferred from the terminal apparatus  211  to the DFE  201  through the network  212  and is taken into the DFE  201  through the first connector  202 . The NIC  101  in the DFE  201  performs a reception process for the data packet. When the data packet received by the NIC  101  is in accordance with TCP/IP protocol, a header information part of the data packet includes the destination port number. 
     Since the destination port number is information that designates a program or a process of an apparatus that receives the data packet to which data should be transmitted, different port numbers are assigned to respective communication protocols or programs. 
     For example, destination port numbers to the communication protocols of SNMP (Simple Network Management Protocol), SLP (Service Location Protocol), and WSD (Web Service on Devices) are Port 161, Port 427 and Port 5357, respectively. 
     Accordingly, when receiving a data packet, the NIC  101  extracts a port number from the header of the received data packet and determines whether the port number corresponds to a print process. Thereby, the NIC  101  is able to determine whether the data packet is print data or other data (control data, for example). 
     When the NIC  101  determines that the received data packet is print data in this step, the CPU  107  controls to write the received print data received into the HDD  105  if necessary. This is queuing (spooling) that is generally performed in order to improve transfer speed of data packet as print data. The print data stored in the HDD  105  is read by the RIP processor  102  in response to an instruction from the CPU  107 . In the meantime, the print data that is not subjected to the queuing is directly transferred to the RIP processor  102  in response to an instruction from the CPU  107 . 
     The RIP processor  102  applies a RIP process to the print data sent to the RIP processor  102 . Subsequently, the encoder  103  encodes the print data to a data format that the MFP  207  can interpret on the basis of preset data formats that the MFP  207  can interpret and the format of the received data. Although the data format of the print data sent to the RIP processor  102  may be a preset data format, it is not limited to this. For example, it may be a data format obtained from the MFP  207  by communication or a data format designated through the operation unit  109 . 
     The encoding process is performed if necessary. Accordingly, when the encoding process is unnecessary because a format of received print data can be interpreted by the MFP  207 , the encoding process can be skipped. The encoded data needs to be in a format that the MFP can interpret. For example, there are various formats, such as a specific print language format, a data format that compresses by a specific method of JPEG or JBIG. Available formats depend on ability of an interpretation means that is built in the MFP  207 . The data encoded as necessary is transferred to the image interface board  111  from the encoder  103 . This data passes the connector  204 , flows through the dedicated transfer path  206 , and is transmitted to the MFP  207  through the fourth connector  209 . 
     Moreover, when the image data scanned by a reader unit  303  ( FIG.  3   ) of the MFP  207  is transmitted to the terminal apparatus  211 , the image data as a data packet is sent out to the network  212  through the third connector  208 . Thereby, the data packet reaches the terminal  211 . 
       FIG.  3    is a block diagram showing a hardware configuration of the MFP  207 . 
     As shown in  FIG.  3   , the MFP  207  consists of a main unit  301  and an image input/output controller  305 . 
     The main unit  301  consists of an operation unit  302 , the reader unit  303 , and a printer unit  304 . 
     The operation unit  302  is used to operate the main unit  301  and the image input/output controller  305 . A display panel for an operation is integrally attached to the operation unit  302 . 
     The reader unit  303  reads an image of a document and outputs image data corresponding to a document image to the printer unit  304  and image input/output controller  305 . 
     The printer unit  304  records an image corresponding to image data transferred from the reader unit  303  or the image input/output controller  305  onto a recording sheet. 
     The image input/output controller  305  is connected to the reader unit  303  and consists of an interface (IF) unit  306 , an image memory  307 , a controller  308 , and an HDD  309 . 
     The third connector  208  and fourth connector  209  are connected to the IF unit  306 . It should be noted that the HDD  309  stores setting information about the MFP  207 , such as an address book, an operation history, a user setting, an ID setting, and a network setting. 
     The IF unit  306  connects to the third and fourth connectors  208  and  209 , and functions as an interface between the DFE  201  and the terminal apparatus  211  on the network  212 . For example, the IF unit  306  receives code data representing an image transferred from the DFE  201  through the fourth connector  209 , develops the received data to image data that the printer unit  304  can record, and passes it to the controller  308 . Moreover, the IF unit  306  receives code data representing image data transferred from the terminal apparatus  211  through the third connector  208 . After that, the IF unit  306  develops the data to data that the printer unit  304  can record if necessary and passes it to the controller  308 . 
     The controller  308  is constituted by a CPU  310 , a ROM  311 , a RAM  312 , etc. 
     The CPU  310  loads a program stored in the ROM  311  or another storage medium onto the RAM  312  and runs it to control flows of data between the reader unit  303 , IF unit  306 , and image memory  307 . The HDD  309  may be replaced with another nonvolatile memory that does not erase data even when power turns off. In such a case, the program is stored in the nonvolatile memory. 
     The MFP  207  has a function to read a document on the reader unit  303  as image data by the reader unit  303  when an instruction to read the document is received from the terminal apparatus  211 . The CPU  310  sends the read image data to the terminal apparatus  211 . 
     In the meantime, unlike the MFP  207 , the DFE  201  does not have a reader unit that reads a document. Accordingly, when the DFE  201  is not connected to the MFP  207 , the DFE  201  cannot read a document. Accordingly, when the DFE  201  receives an instruction to read a document from the terminal apparatus  211  in the state where the DFE  201  is not connected to the MFP  207 , the CPU  107  rejects the instruction. 
     In the meantime, when the DFE  201  is connected to the MFP  207 , the DFE  201  can request the MFP  207  to read a document using the reader unit  303 . Accordingly, when the DFE  201  receives an instruction to read a document from the terminal apparatus  211  in the state where the DFE  201  is connected to the MFP  207 , the CPU  107  transfers the instruction to the MFP  207 . When receiving the transferred instruction, the CPU  310  controls the reader unit  303  to read a document on the reader unit  303  as image data and transmits the read image data to the DFE  201  and the CPU  310  transmits the image data to the terminal apparatus  211 . 
     Subsequently, switching control of network ports of the DFE  201  on the basis of a connection configuration of the MFP  207  of this embodiment will be described using  FIG.  4    and  FIG.  5   . 
       FIG.  4    is a flowchart showing a process for determining a connection configuration of the MFP  207  of this embodiment executed by the MFP  207 . 
     The process in  FIG.  4    is achieved because the CPU  310  of the MFP  207  reads the program stored in the ROM  311  to the RAM  312  and runs it. 
     In a step S 401 , the CPU  310  (an obtainment unit) obtains connection information (information representing a connection configuration) about the MFP  207  and proceeds with the process to a step S 402 . 
     The connection information about the MFP  207  is network setting information about the MFP  207  that is input by a user through the operation unit  302  of the MFP  207  and is stored in the RAM  312  of the MFP  207 . Hereinafter, a case where the user inputs a value of DFE_SW as the connection information about the MFP  207  will be described. In addition, the connection information about the MFP  207  may be set and held in the HDD  309  of the MFP  207 . 
     In addition, when the MFP  207  is connected to the network  212  through the third connector  208  (the third connector  208  is valid) and the MFP  207  is connected to the DFE  201  through the fourth connector  209  (the fourth connector  209  is valid), the value of DFE_SW is “0”. Moreover, when the MFP  207  is not connected to the network  212  through the third connector  208  (the third connector  208  is invalid) but the MFP  207  is connected to the DFE  201  through the fourth connector  209  (the fourth connector  209  is valid), the value of DFE_SW is “1”. When the MFP  207  is not connected to the DFE  201  through the fourth connector  209  (the fourth connector  209  is invalid), the value of DFE_SW is 2. 
     In a step S 402 , the CPU  310  checks the value of DFE_SW obtained in the step S 401 . Specifically, when the value of the obtained DFE_SW is “0” (DFE_SW=0 in the step S 402 ), the CPU  310  proceeds with the process to a step S 403 . Moreover, when the value of the obtained DFE_SW is “1” (DFE_SW=1 in the step S 402 ), the CPU  310  proceeds with the process to a step S 404 . Moreover, when the value of the obtained DFE_SW is “2” (DFE_SW=2 in the step S 402 ), the CPU  310  proceeds with the process to a step S 405 . 
     In the step S 403 , the CPU  310  stores a connection determination result (connection targets: DFE and network) obtained in the step S 402  into the RAM  312  as the connection information about the MFP  207 . And then, the CPU  310  proceeds with the process to a step S 406 . 
     In the step S 404 , the CPU  310  stores a connection determination result (connection targets: DFE only) obtained in the step S 402  into the RAM  312  as the connection information about the MFP  207 . And then, the CPU  310  proceeds with the process to the step S 406 . 
     In the step S 405 , the CPU  310  stores a connection determination result (connection targets: others) obtained in the step S 402  into the RAM  312  as the connection information about the MFP  207 . And then, the CPU  310  finishes the process as-is. 
     In the step S 406 , the CPU  310  determines whether the MFP  207  is communicable with the DFE  201  using the IF unit  306 . As a result of the determination, when the MFP  207  is communicable with the DFE  201  (YES in the step S 406 ), the CPU  310  proceeds with the process to a step S 407 . In the meantime, when the MFP  207  is not communicable with the DFE  201  (NO in the step S 406 ), the CPU  310  returns the process to the step S 406 . 
     In the step S 407 , the CPU  310  sends the connection information about the MFP  207  stored in the RAM  312  to the DFE  201 . And then, the CPU  310  finishes this process. 
       FIG.  5    is a flowchart showing a network-port switching control process of this embodiment executed by the DFE  201   
     The process in  FIG.  5    is achieved because the CPU  107  of the DFE  201  reads the program stored in the ROM  106  to the RAM  108  and runs it. 
     In a step S 501 , the CPU  107  determines whether the DFE  201  is communicable with the MFP  207  using the NIC  104 . As a result of the determination, when the DFE  201  is communicable with the MFP  207  (YES in the step S 501 ), the CPU  107  proceeds with the process to a step S 502 . In the meantime, when the DFE  201  is not communicable with the MFP  207  (NO in the step S 501 ), the CPU  310  repeats the process in the step S 501 . 
     In the next step S 502 , the CPU  107  receives the connection information about the MFP  207  from the MFP  207 . And then, the CPU  107  proceeds with the process to a step S 503 . 
     In the next step S 503 , the CPU  107  determines whether the connection information about the MFP  207  received in the step S 502  shows that the MFP  207  is connected to the DFE  201  and network  212 . As a result of the determination, when the received connection information about the MFP  207  shows that the MFP  207  is connected to the DFE  201  and network  212  (YES in the step S 503 ), the CPU  107  proceeds with the process to a step S 504 . In the meantime, if this is not the case, specifically, when the received connection information about the MFP  207  shows that the MFP  207  is connected to the DFE  201  only (NO in the step S 503 ), the CPU  107  finishes this process as-is. In the step S 503 , it is enough to determine whether the received connection information about the MFP  207  shows that the MFP  207  is connected to the network  212 . That is, it is unnecessary to determine whether the information shows that the MFP  207  is connected to the DFE  201 . 
     In the step S 504 , the CPU  107  (a port controller) closes a network port (a predetermined network port) of a port number  47545  of the connector  202  of the DFE  201 . And then, the CPU  107  finishes this process. In addition, the network port of the port number  47545  of the connector  202  is used when an application of the terminal apparatus  211  communicates with the MFP  207  through the DFE  201 . 
     This prevents a situation where the MFP  207  that is directly connected to the network  212  and the MFP  207  that is indirectly connected to the network  212  through the DFE  201  are found when the application of the terminal apparatus  211  searches the network for an available apparatus. That is, when the network port of the port number  47545  of the first connector  202  is closed, the application of the terminal apparatus  211  cannot find the DFE  201  and can find only the MFP  207  that is directly connected to the network  212 . Since this prevents duplicated display of the MFP  207  as a search result by the application of the terminal apparatus  211 , the user is not confused. 
     The MFP  207  may obtain the function for which the application of the terminal apparatus  211  searches. In such a case, the MFP  207  may switch whether to execute the processes in  FIG.  4    and  FIG.  5    in accordance with the obtained function. 
     Specifically, only when the function for which the application of the terminal apparatus  211  searches is a function (communication using IPv6 or IPsec, for example) of the MFP  207  that cannot be used through the DFE  201 , the processes in  FIG.  4    and  FIG.  5    may be executed. As a result, when the user wants to use a function of the MFP  207  that cannot be used through the DFE  201 , only the MFP  207  directly connected to the network  212  is displayed as a search result by the application of the terminal apparatus  211 . Accordingly, the user can certainly select the apparatus that can use the function desired by the user from the search result by the application of the terminal apparatus  211 . 
     In the meantime, when the function for which the application of the terminal apparatus  211  searches is a function (print or scan, for example) of the MFP  207  that can be used through the DFE  201 , the processes in  FIG.  4    and  FIG.  5    may not be executed. Although this cannot prevent the duplicated display of the MFP  207  as the search result by the application of the terminal apparatus  211 , the user can select the MFP  207  connected to the DFE  201  when the user wants to use the MFP  207  through the DFE  201 . 
     Moreover, network ports (for example, the port numbers  137 ,  138 ,  443 ,  9100 , etc.) of the print function of the DFE  201  that does not use the MFP  207  through DFE  201  are not controlled to close in this embodiment. 
     Although the CPU  107  controls to close the network port of the port number  47545  of the first connector  202  in the step S 504  in this embodiment, the control is not limited to this. For example, the CPU  107  may also close a network port of a port number  8000  that provides Web service of the MFP  207  used by the communication that uses the MFP  207  through the DFE  201  in the step S 504 . 
     Moreover, the CPU  107  may control to close a plurality of network ports of the first connector  202  in the step S 504 . For example, in a conventional system, both of the MFP  207  and the DFE  201  that browses the MFP  207  are displayed on the display unit of the terminal apparatus  211  as a search result of available printers on the network  212  by the printer driver installed in the terminal apparatus  211 . In order not to display the DFE  201  as a printer that the printer driver of the terminal apparatus  211  can use, the CPU  107  may control to close the network ports of the port numbers  161  and  427  of the first connector  202  in the step S 504 . 
     Although the case where the second connector  203  of the DFE  201  is connected to the fourth connector  209  of the MFP  207  is described in this embodiment, the connection between the MFP  207  and DFE  201  is not limited to this. For example, one of the connectors  202 ,  203 , and  204  of the DFE  201  may be connected to the third connector  208  of the MFP  207 . 
     Moreover, although the MFP  207  is connected to the network  212  through the third connector  208 , the connection to the network  212  is not limited to this. For example, when the MFP  207  has a wireless communication unit, the MFP  207  may be connected to the network  212  using the wireless communication unit. 
     Moreover, the switching control of the network port of the first connector  202  is performed in accordance with the connection configuration between the DFE  201  and MFP  207  in this embodiment. Furthermore, the DFE  201  may control to open and close of the network port by determining communication state of the MFP  207  on the network  212 . For example, the case where the communication state of the third connector  208  of the MFP  207  is invalid and the fourth connector  209  of the MFP  207  is communicable with the second connector  203  of the DFE  201  is determined to be equivalent to the connection configuration where only the DFE  201  is connected to the MFP  207 . In such a case, the switching control of the network ports of the DFE  201  may be performed as with the case where DFE_SW is “1”. 
     Moreover, although the user inputs the connection information about the MFP  207  through the operation unit  302  of the MFP  207 , it may be input through the operation unit  109  of the DFE  201 . 
     Next, a second embodiment will be described. In the first embodiment, the switching control of the network port of the DFE  201  is performed using the connection information about the MFP  207  that the user inputs through the operation unit  302  of the MFP  207  in the step S 401 . As compared with this, in this embodiment, the switching control of the network port of the DFE  201  is performed using network information that the MFP  207  has. 
     Hereinafter, a configuration and step in this embodiment that are identical to that in the first embodiment are indicated by the same reference numerals, and a duplicated description is omitted. 
       FIG.  6    is a flowchart showing a process for determining a connection configuration of the MFP  207  of this embodiment executed by the MFP  207 . 
     The process in  FIG.  6    is achieved because the CPU  310  of the MFP  207  reads the program stored in the ROM  311  to the RAM  312  and runs it. 
     In a step S 601 , the CPU  310  obtains the network information about the MFP  207  and saves it to the RAM  312 . And then, the process proceeds to a step S 602 . 
     The network information about the MFP  207  includes network settings of the connectors  280  and  209  of the MFP  207 , and specifically, values of a network address and a subnet mask, which are held in the HDD  309  of the MFP  207 . It should be noted that the user may input the above-mentioned network information about the MFP  207  using the operation unit  302 . 
     The connection of the MFP  207  and DFE  201  uses a fixed network address. When the network information obtained in the step S 601  includes the fixed network address, it is determined that the MFP  207  is connected to the DFE  201 . In the meantime, when the network information obtained in the step S 601  includes an address other than the fixed network address, it is determined that the MFP  207  is connected to the network  212 . 
     In the step S 602 , the CPU  310  determines the connection configuration of the MFP  207  using the network information about the MFP  207  held in the RAM  312 . When it is determined that the MFP  207  connects to the DFE  201  and network  212  as a result of the determination (DFE and Network in the step S 602 ), the CPU  310  proceeds with the process to a step S 603 . Moreover, when it is determined that the MFP  207  is connected to only the DFE  201  (Only DFE in the step S 62 ), the CPU  310  proceeds with the process to a step S 604 . Moreover, when the determination result is “Other” (Other in the step S 602 ), the CPU  310  proceeds with the process to a step S 605 . 
     In the step S 603 , the CPU  310  substitutes “0” for the value of DFE_SW showing a network connection configuration of the MFP  207  and stores it in the RAM  312 . And then, the CPU  310  proceeds with the process to the step S 402 . 
     In the step S 604 , the CPU  310  substitutes “1” for the value of DFE_SW showing the network connection configuration of the MFP  207  and stores it in the RAM  312 . And then, the CPU  310  proceeds with the process to the step S 402 . 
     In the step S 605 , the CPU  310  substitutes “2” for the value of DFE_SW showing the network connection configuration of the MFP  207  and stores it in the RAM  312 . And then, the CPU  310  proceeds with the process to the step S 402 . 
     After that, the CPU  310  executes the steps S 402  through S 407  that have been described by referring to  FIG.  4    and finishes this process. 
     Next, a third embodiment will be described. The first embodiment presupposes that the first connector  202  of the DFE  201  and the third connector  208  of the MFP  207  are connected to the same network  212 . As compared with this, this embodiment supposes a case where the first connector  202  of the DFE  201  and the third connector  208  of the MFP  207  are respectively connected to different networks. 
     Hereinafter, a configuration and step in this embodiment that are identical to that in the first and second embodiments are indicated by the same reference numerals, and a duplicated description is omitted. 
       FIG.  7    is a schematic view showing a connection configuration of an image forming system  1   b  of this embodiment. 
     As shown in  FIG.  7   , the image forming system  1   b  includes a network  702  that is different from the network  212  in addition to the network  212 . 
     The terminal apparatus  211  and MFP  207  are connected to the network  212 , but the DFE  201  is not connected to the network  212 . In the meantime, a terminal apparatus  701  and the DFE  201  are connected to the network  702 , but the MFP  207  is not connected to the network  702 . Moreover, the DFE  201  is connected to the MFP  207  through the dedicated transfer path  206  as with the first embodiment. 
     The DFE  201  is provided with the connectors  202 ,  203 , and  204 . The first connector  202  is an NIC connector that manages the connection to the network  702  at the low layer level. The second connector  203  is an interface for the dedicated transfer path  206 . The connector  204  is a connector for the dedicated transfer path through which image data is transmitted to the MFP  207  when the DFE  201  generates the image data. The connector  204  is not used in this embodiment. 
     The MFP  207  is provided with the connectors  208  and  209 . The third connector  208  is a connector for an NIC like Ethernet (registered trademark) that manages connection to the network  212  at the low layer level. The fourth connector  209  is an interface for the dedicated transfer path  206 . 
     The image forming system  1   b  of this embodiment is characterized in that the DFE  201  and MFP  207  are connected through the dedicated transfer path  206  and that the MFP  207  is connected to the network  212 . Data on the network  702  is taken into the DFE  201  through the first connector  202 . Print data sent out to the dedicated transfer path  206  through the second connector  203  of the DFE  201  is taken into the MFP  207  through the fourth connector  209 . 
     Although the case where the second connector  203  of the DFE  201  is connected to the fourth connector  209  of the MFP  207  is described in this embodiment, the connection between the MFP  207  and DFE  201  is not limited to this. For example, the second connector  203  of the DFE  201  may be connected to the third connector  208  of the MFP  207 . In this case, the fourth connector  209  of the MFP  207  is connected to the network  212 . 
     Subsequently, switching control of network ports of the DFE  201  on the basis of the connection configuration of the MFP  207  of this embodiment will be described using  FIG.  8   . Since the network-port switching control process executed by the DFE  201  is the same as that of the first embodiment in  FIG.  5   , its description is omitted. 
       FIG.  8    is a flowchart showing a process for determining a connection configuration of the MFP  207  of this embodiment executed by the MFP  207 . 
     The process in  FIG.  8    is achieved because the CPU  310  of the MFP  207  reads the program stored in the ROM  311  to the RAM  312  and runs it. 
     In a step S 601 , the CPU  310  obtains the network information about the MFP  207  and saves it to the RAM  312 . And then, the process proceeds to a step S 801 . 
     The network information about the MFP  207  includes values of a network address and a subnet mask set to the third connector  208  of the MFP  207 , which are held in the HDD  309  of the MFP  207 . 
     In the step S 801 , the CPU  310  obtains the network information about the DFE  201  and saves it to the RAM  312 . And then, the process proceeds to a step S 802 . 
     The network information about the DFE  201  includes values of a network address and subnet mask set to the first connector  202  of the DFE  201  that are included in MIB held in the HDD  309  of the DFE  201 . 
     In the step S 802 , the CPU  310  determines whether the MFP  207  and DFE  201  are connected to the same network by comparing the network information about the MFP  207  with the network information about the DFE  201  that are held in the RAM  312 . Specifically, the CPU  310  reads the values of the network address and subnet mask set to the third connector  208  of the MFP  207  that are stored in the RAM  312  in the step S 601 , and obtain the network information about the MFP  207  from a logical product of them. Similarly, the CPU  310  reads the values of the network address and subnet mask set to the first connector  202  of the DFE  201  that are stored in the RAM  312  in the step S 801 , and obtains the network information about the DFE  201  from a logical product of them. After that, the CPU  3107  compares the obtained network information about the MFP  207  with the obtained network information about the DFE  201 . 
     When the compared values of the network information about the MFP  207  and DFE  201  are identical, the CPU  310  determines that the MFP  207  and DFE  201  are connected to the same network (YES in the step S 802 ) as shown in  FIG.  1    and proceeds with the process to a step S 803 . In the meantime, when the compared values of the network information about the MFP  207  and DFE  201  are different, the CPU  310  determines that the MFP  207  and DFE  201  are respectively connected to the different networks (NO in the step S 802 ) as shown in  FIG.  7    and proceeds with the process to a step S 804 . 
     A case where the MFP  207  and DFE  201  are connected to the same network is equivalent to the case where the value of DFE_SW of the network connection configuration as shown in  FIG.  1    is “0”. Accordingly, in the step S 803 , the CPU  310  substitutes “0” for the value of DFE_SW showing the network connection configuration of the MFP  207  and stores it as the connection information about the MFP  207  in the RAM  312 . And then, the CPU  310  proceeds with the process to a step S 805 . 
     Moreover, the case where the MFP  207  and DFE  201  are connected to the different networks as shown in  FIG.  7    is equivalent to the connection configuration where the MFP  207  is connected to only the DFE  201  when viewed from the terminal apparatus  701  because the third connector  208  of the MFP  207  is not communicable with the first connector  202  of the DFE  201 . Accordingly, in the step S 804 , the CPU  310  substitutes “1” for the value of DFE_SW showing the network connection configuration of the MFP  207  and stores it as the connection information about the MFP  207  in the RAM  312 . And then, the CPU  310  proceeds with the process to the step S 805 . 
     In the step S 805 , the CPU  310  determines the connection configuration of the MFP  207  using the value of DFE_SW held in the RAM  312  in the last step (the step S 803  or S 804 ). Specifically, when the value of DFE_SW held in the RAM  312  is “0” (DFE_SW=0 in the step S 805 ), the CPU  310  proceeds with the process to the step S 403 . In the meantime, when the value of DFE_SW held in the RAM  312  is “1” (DFE_SW=1 in the step S 805 ), the CPU  310  proceeds with the process to the step S 404 . 
     After that, the CPU  310  executes the steps S 403 , S 404 , S 406 , and S 407  that have been described by referring to  FIG.  4    and finishes this process. 
     As mentioned above, in this embodiment, when the DFE  201  and MFP  207  are connected to the same network (for example, the network  212 ), the network port of the port number  47545  of the first connector  202  of the DFE  201  is controlled to close. 
     In the meantime, when the MFP  207  and DFE  201  are respectively connected to the different networks  212  and  702 , the network port of the port number  47545  of the first connector  202  of the DFE  201  is controlled to keep opening without closing. Thereby, the user is able to use the function of the MFP  207  on both of the different networks. 
     Although the switching control of a port of the first connector  202  of the DFE  201  is described in this embodiment, a port to be controlled is not limited to this. Switching of a plurality of ports of the first connector  202  of the DFE  201  may be controlled. 
     Next, a fourth embodiment will be described. In the first embodiment, the MFP  207  determines the connection configuration of the MFP  207  and sends the connection information to the DFE  201 . Then, the DFE  201  controls the switching of the network port of the first connector  202  of the DFE  201  using the connection information received from the MFP  207 . As compared with this, in this embodiment, the DFE  201  determines whether the MFP  207  and DFE  201  are connected to the same network and controls the switching of the network port of the first connector  202  of the DFE  201  using the determination result. 
     Hereinafter, a configuration in this embodiment that is identical to that in the first embodiment is indicated by the same reference numeral, and a duplicated description is omitted. 
       FIG.  9    is a flowchart showing a network-port switching control process of this embodiment executed by the DFE  201 . 
     The process in  FIG.  9    is achieved because the CPU  107  of the DFE  201  reads the program stored in the ROM  106  to the RAM  108  and runs it. 
     In a step S 901 , the CPU  107  receives the connection information about the DFE  201 . And then, the CPU  107  proceeds with the process to a step S 902 . 
     The connection information about the DFE  201  includes values showing network settings of the connectors  202  and  208  that are input through the operation unit  109  of the DFE  201  and are stored in the RAM  108 . Hereinafter, a case where the user inputs a value (DFENET) showing whether both of the DFE  201  (the first connector  202 ) and the MFP  207  (the third connector  208 ) are connected to the network  212  as the connection information about the DFE  201  will be described. When the connection configuration shows that both of the DFE  201  and MFP  207  are connected to the network  212 , the value of DFENET is set to “0”. When the DFE  201  and MFP  207  are in another connection configuration, the value of DFENET is set to “1”. 
     In the step S 902 , the CPU  310  checks the value of DFENET obtained in the step S 901 . Specifically, when the value of DFENET is “0” (DFENET=0 in the step S 902 ), the CPU  310  proceeds with the process to a step S 903 . In the meantime, when the value of the DFENET is “1” (DFENET=1 in the step S 902 ), the CPU  310  proceeds with the process to a step S 904 . 
     In the step S 903 , the CPU  107  stores “connected to same network” in the RAM  108  as the connection configuration of the DFE  201  and MFP  207 . And then, the CPU  107  proceeds with the process to a step S 905 . 
     In the step S 904 , the CPU  107  stores “other connection” in the RAM  108  as the connection configuration of the DFE  201  and MFP  207 . And then, the CPU  107  finishes this process. In this case, the network port of the port number  47545  of the first connector  202  of the DFE  201  is controlled to keep opening. 
     In the step S 905 , the CPU  107  closes the network port of the port number  47545  of the first connector  202  of the DFE  201 . And then, the CPU  107  finishes this process. 
     Next, a fifth embodiment will be described. In the fourth embodiment, the switching of the network port of the first connector  202  of the DFE  201  is controlled using the connection information about the DFE  201  input by the user through the operation unit  302  of the DFE  201 . As compared with this, in this embodiment, it is determined whether the DFE  201  and MFP  207  are connected to the same network using the network information held by the DFE  201  holds and the network information obtained from the MFP  207 , and the switching of the network port of the first connector  202  of the DFE  201  is controlled. 
     Hereinafter, a configuration in this embodiment that is identical to that in the fourth embodiment is indicated by the same reference numeral, and a duplicated description is omitted. 
       FIG.  10    is a flowchart showing a network-port switching control process of this embodiment executed by the DFE  201   
     The process in  FIG.  10    is achieved because the CPU  107  of the DFE  201  reads the program stored in the ROM  106  to the RAM  108  and runs it. 
     In a step S 1001 , the CPU  107  obtains the connection information about the DFE  201  and MFP  207 . Specifically, the CPU  107  obtains values of a network address and subnet mask of the first connector  202  of the DFE  201  that are stored in the HDD  105  of the DFE  201  as the connection information about the DFE  201 . Moreover, the CPU  107  obtains values of a network address and subnet mask of the third connector  208  of the MFP  207  included in the MIB held in the HDD  309  of the MFP  207  as the connection information about the MFP  207 . After that, the CPU  107  proceeds with the process to a step S 1002 . 
     In the step S 1002 , the CPU  107  determines whether the MFP  207  and DFE  201  are connected to the same network on the basis of the connection information about the DFE  201  and MFP  207  obtained in the step S 1001 . Specifically, the CPU  107  obtains the network information about the DFE  201  from the logical product of the network address and subnet mask of the first connector  202  of the DFE  201  obtained in the step S 1001 , Similarly, the CPU  107  obtains the network information about the MFP  207  from the logical product of the network address and subnet mask of the third connector  208  of the MFP  207  obtained in the step S 1001 . After that, the CPU  3107  compares the obtained network information about the MFP  207  with the obtained network information about the DFE  201 . 
     When the compared values of the network information about the MFP  207  and DFE  201  are identical, the CPU  310  determines that the MFP  207  and DFE  201  are connected to the same network (YES in the step S 1002 ) and proceeds with the process to a step S 1003 . In the meantime, when the compared values of the network information about the MFP  207  and DFE  201  are different, the CPU  310  determines that the connection configuration of the MFP  207  and DFE  201  is another connection configuration (NO in the step S 1002 ) and proceeds with the process to a step S 1004 . For example, when the DFE  201  is not connected to the MFP  207  or when the DFE  201  and MFP  207  are respectively connected to different networks, the CPU  310  determines that it is another connection configuration. 
     In the step S 1003 , the CPU  107  substitutes the value “0” showing that the DFE  201  and MFP  207  are connected to the network  212  for DFENET and stores it in the RAM  108 . Then, the CPU  1007  proceeds with the process to the step S 902 . 
     In the step S 1004 , the CPU  107  substitutes the value “1” showing the connection configuration other than the configuration where the DFE  201  and MFP  207  are connected to the network  212  for DFENET and stores it in the RAM  108 . Then, the CPU  1007  proceeds with the process to the step S 902 . 
     In the next step S 902 , the CPU  107  checks the value of DFENET obtained in the last step (step S 1003  or step S 1004 ). Specifically, when the value of DFENET is “0” (DFENET=0 in the step S 902 ), the CPU  310  proceeds with the process to a step S 903 . In the meantime, when the value of the DFENET is “1” (DFENET=1 in the step S 902 ), the CPU  310  proceeds with the process to a step S 904 . 
     After that, the CPU  310  executes the steps S 903  through S 905  that have been described by referring to  FIG.  9    and finishes this process. 
     OTHER EMBODIMENTS 
     Embodiment(s) of the present invention can also be realized by a computer of a system or apparatus that reads out and executes computer executable instructions (e.g., one or more programs) recorded on a storage medium (which may also be referred to more fully as anon-transitory computer-readable storage medium’) to perform the functions of one or more of the above-described embodiment(s) and/or that includes one or more circuits (e.g., application specific integrated circuit (ASIC)) for performing the functions of one or more of the above-described embodiment(s), and by a method performed by the computer of the system or apparatus by, for example, reading out and executing the computer executable instructions from the storage medium to perform the functions of one or more of the above-described embodiment(s) and/or controlling the one or more circuits to perform the functions of one or more of the above-described embodiment(s). The computer may comprise one or more processors (e.g., central processing unit (CPU), micro processing unit (MPU)) and may include a network of separate computers or separate processors to read out and execute the computer executable instructions. The computer executable instructions may be provided to the computer, for example, from a network or the storage medium. The storage medium may include, for example, one or more of a hard disk, a random-access memory (RAM), a read only memory (ROM), a storage of distributed computing systems, an optical disk (such as a compact disc (CD), digital versatile disc (DVD), or Blu-ray Disc (BD)™), a flash memory device, a memory card, and the like. 
     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. 2021-183415, filed Nov. 10, 2021, which is hereby incorporated by reference herein in its entirety.