Patent Publication Number: US-2015063184-A1

Title: Information processing system, managing apparatus, control method for managing apparatus, and storage medium

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an information processing system, a managing apparatus, a control method for the managing apparatus, and a storage medium configured to execute the control method. In particular, the present invention relates to the information processing system that includes a plurality of multifunction printer apparatuses provided with, for example, a facsimile function that includes a communication apparatus, and relates to a communication control method for that apparatus. 
     2. Description of the Related Art 
     Typically, network communication using a wireless LAN is widely used. Network communication is enabled between a backbone network and a wireless LAN terminal by wireless communication connection of the wireless LAN terminal and a wireless LAN access point connected to the backbone network by the wireless LAN. In recent years, in addition to network communication on the wireless LAN, a configuration has been proposed which uses the wireless LAN to detect a position of the wireless LAN terminal. A representative example of such a configuration is the time difference of arrival (TDOA) method. The TDOA method measures the position of the wireless LAN terminal from the difference in the arrival time of a wireless signal by simultaneous reception of the wireless signal sent from the wireless LAN terminal by a plurality of wireless LAN access points. Therefore, the principle of the TDOA method requires capture of the wireless signal from the wireless LAN terminal by the constantly required plurality of wireless LAN access points. 
     On the other hand, an MFP apparatus (information processing apparatus) provided with a plurality of functions such as copying, printing, scanning, FAX, and the like has found general application in office duties. In that context, in recent years, there has been a tendency to provide a new function(s) by execution of wireless LAN communication between a tablet PC or smartphone provided with a wireless LAN function that are undergoing the rapid expansion of application. More specifically, it has been proposed to provide a function such as printing or scanning by using a tablet PC or smartphone in a configuration in which wireless LAN communication is performed with a tablet PC or smartphone that is the wireless LAN terminal by mounting an access point for the wireless LAN in the MFP apparatus. When the access point for the wireless LAN is provided in the MFP apparatus, use in conjunction with a position detection system for the wireless LAN terminal as described above enables consideration of a new MFP function in which the position of the tablet PC or smartphone, that is the wireless LAN terminal, is detected and that position information is used. 
     However, when many users perform wireless communication on a system configured from the wireless LAN access point and the wireless LAN terminal, the plurality of wireless LAN access points must be provided in order to ensure connection of the wireless communication circuit. However, when the number of connected wireless LAN terminals is low, unnecessary power consumption can be avoided by operating only the required number of wireless LAN access points. In this context, Japanese Patent Laid-Open No. 2003-174456 discloses a system configured from the plurality of wireless LAN access points that is configured to shift the wireless LAN access points that are not required to a power-saving state. 
     Japanese Patent Laid-Open No. 2003-174456 discloses a method for shifting the wireless LAN access points that are not connected with the wireless LAN terminal to the power-saving state by controlling the wireless LAN access points to switch between a normal state and the power-saving state. 
     In the MFP apparatus, there is a strong demand to reduce unnecessary power consumption. As a result, a sleep mode is generally provided so that, when a function is not provided, the energized to unnecessary units in the apparatus is switched to an OFF state and thereby configures the power-saving state. When the wireless LAN access point is mounted in the MFP apparatus, as disclosed in the method in Japanese Patent Laid-Open No. 2003-174456, the wireless LAN access points that are not required are placed in an OFF state and the apparatus shifts to a sleep mode to thereby save power consumption. 
     However, on the other hand, when performing position detection of the wireless LAN terminal, operation of the plurality of wireless LAN access points is constantly required in a typical TDOA method. As a result, if respective MFP apparatuses shift randomly to a sleep mode in accordance with the method disclosed in Japanese Patent Laid-Open No. 2003-174456, the number of wireless LAN access points cannot cover the number that is required for position detection and therefore position detection of the wireless LAN terminal is not possible. 
     SUMMARY OF THE INVENTION 
     The present invention provides an information processing system is configured to enable power saving and includes a plurality of MFP apparatuses that are constantly provided with wireless LAN access points that enable position detection of a wireless LAN terminal by use of the wireless LAN access points. 
     According to an aspect of the present invention, an information processing system that includes a wireless communication terminal; a plurality of information processing apparatuses having an access point configured to perform wireless communication with the wireless communication terminal; and a managing apparatus configured to manage the information processing apparatuses, wherein the information processing apparatuses comprises: a detecting unit configured to detect an energized state of the access point and send the energized state as a detection signal to the managing apparatus, and a control unit configured to switch the access point to a standby mode or a power-saving mode, wherein the managing apparatus comprises: a sending unit configured to send a mode switch signal to the control unit in response to the detection signal from the detecting unit, and wherein when a position of the wireless communication terminal is detected, the sending unit sends the mode switch signal in response to the detection signal to the control unit in order to switch a predetermined number or more of access points to the standby mode, and the control unit which has received the mode switch signal switches the access points to the standby mode. 
     According to the present invention, the information processing system can be configured for power saving, and includes the plurality of MFP apparatuses that are constantly provided with wireless LAN access points that enable position detection of the wireless LAN terminal by use of the wireless LAN access points may be provided. 
     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 diagram illustrating a schematic configuration of the MFP apparatus including a wireless LAN function. 
         FIG. 2  is a block diagram illustrating the MFP apparatus according to a first embodiment of the present invention. 
         FIG. 3  is a diagram illustrating position detection of a wireless LAN terminal according to a first embodiment of the present invention. 
         FIG. 4  is a flowchart illustrating the setting operation of a position detection and MFP control server. 
         FIG. 5  is a table illustrating a power consumption profile of the MFP apparatus. 
         FIG. 6  is a flowchart illustrating the operation of standby mode in the MFP apparatus. 
         FIG. 7  is a flowchart illustrating the operation of sleep mode in the MFP apparatus. 
         FIG. 8  is a flowchart illustrating the operation when performing position detection. 
         FIG. 9  is a table illustrating the respective MFP states resulting from operation of the position-detection MFP-control server. 
         FIG. 10  is a flowchart illustrating the operation when not performing position detection. 
     
    
    
     BRIEF DESCRIPTION OF THE EMBODIMENTS 
     Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. 
       FIG. 1  is a diagram illustrating a schematic configuration of a system (information processing system) configured from an MFP apparatus provided with a wireless LAN function (wireless communication function) according to a first embodiment of the present invention. The MFP (information processing apparatus)  101  is the MFP apparatus, configured as a multifunction printer apparatus that includes functions such as copying, printing, scanning. An internal portion of the MFP  101  includes a wireless LAN access point  101   a . An MFP  102 , an MFP  103 , and an MFP  104  denote the same MFP apparatus as the MFP  101 , and respectively include a wireless LAN access point  102   a , a wireless LAN access point  103   a , and a wireless LAN access point  104   a.    
     A position-detection MFP-control server (managing apparatus)  105  is a server (computer) configured to perform control of position detection of a wireless LAN terminal and control of power saving in the MFP  101  to  104 . A position detection master point  106  performs synchronous control of the wireless LAN access point  101   a  to wireless LAN access point  104   a  when performing position detection of the wireless LAN terminal. 
     A client PC  107  is a PC used when a user performs network printing or network scanning operations. A LAN  108  is a local area network circuit, and performs communication control by various types of network protocols such as TCP/IP or the like. Furthermore, the LAN  108  is connected to the MFP  101  to the MFP  104 , the position-detection MFP-control server  105 , the position-detection master point  106  and the client PC  107 . 
     A mobile terminal (wireless communication terminal)  109  is the wireless LAN terminal, and performs wireless LAN communication with the wireless LAN access point  101   a  to the wireless LAN access point  104   a  to thereby enable printing on the MFP  101  to MFP  104  by operating the mobile terminal  109 . More specifically, the mobile terminal  109  corresponds to a tablet PC terminal, smartphone terminal or the like that is provided with, for example, the wireless LAN terminal function. 
       FIG. 2  is a block diagram illustrating the MFP  101  illustrated in  FIG. 1 . A central control unit  201  performs integral control of the MFP  101 . More specifically, the central control unit  201  may be configured by a CPU. A reading unit  202  performs reading of an image in a document during copying and scanning operation. The reading unit  202  more specifically is configured as an image scanner, or the like. 
     An image processing unit  203  performs various types of image processing in relation to recording an image or reading of the image during copying, scanning or printing operations. More specifically, the image processing unit  203  performs print image processing for printing of image data or RIP processing of print data during printing operations by use of a printing unit  205  described below. The image processing unit  203  performs adjustment processing of an image, or reading correction in relation to image data that has been read by the reading unit  202 . 
     A wireless LAN access point unit  204  includes a function as the access point for the wireless LAN, and performs wireless LAN communication with the mobile terminal  109 . The wireless LAN access point unit  204  corresponds to the wireless LAN access point unit  101   a . The printing unit  205  prints an image on a recording sheet. In the apparatus according to the present embodiment, printing is executed by use of an electrophotographic method. 
     A memory unit  206  combines a dynamic memory for use during various types of control operations by the central control unit  201  and a programmable memory that stores programs for execution of control operations. More specifically, the memory unit  206  is configured by a ROM, a RAM, or the like. The image memory unit  207  is a memory configured to store an image and stores and retains an image for printing on the printing unit  205 . 
     A job managing unit  208  is configured to manage various jobs such as copying, printing and scanning that are performed by the MFP  101 . A sleep shift control unit  209  controls a shift to sleep mode (power saving mode) by the MFP  101 , and notifies the central control unit  201  when an operation input is not received by the MFP  101  or when a print job is not received from the LAN  108 , within a predetermined time. The sleep shift control unit  209  according to the present embodiment notifies the central control unit  201  three minutes prior to a sleep shift setting time. 
     An operating unit  210  is configured from a display unit and an operation button for performance of various operations by a user on the MFP  101 . An operation input detecting unit  211  detects the user operation of the operating unit  210 , and more specifically, detects that the operation button of the operating unit  210  has been depressed. 
     A LAN control unit  212  controls LAN communication, and more specifically, controls communication by a network protocol such as TCP/IP. A LAN signal reception detecting unit  213  detects a packet signal from the LAN, and is configured to identify the packet signal from the LAN and to detect an activation packet addressed to its own device in the present embodiment. The LAN control unit  212  and the LAN signal reception detecting unit  213  are connected to the LAN  108 . 
     An activation detection control unit  214  is configured to activate the central control unit  201  in response to detection by the operation input detecting unit  211  that the operation button has been depressed, or detection by the LAN signal reception detecting unit  213  of an activation packet. The MFP  102 , the MFP  103 , and the MFP  104  are configured from the respective blocks illustrated in  FIG. 2  in the same manner as the MFP  101 . 
     Next, a description will be given of switching of energized to each block during sleep mode and standby mode with reference to the block configuration illustrated in the block diagram in  FIG. 2 . Firstly, during standby mode, a function is enabled in which the blocks (all the blocks in the block diagram in  FIG. 2 ) included in an energized unit  215  during standby mode are supplied with power (energized). 
     On the other hand, during sleep mode, the function is enabled in which only the blocks included in an energized unit  216  during sleep mode are supplied with power (energized), and the other blocks are not supplied with power. More specifically, in the present embodiment, during sleep mode, the function is enabled in which only the operation input detecting unit  211 , the LAN signal reception detecting unit  213 , and the activation detection control unit  214  are supplied with power. Therefore, during sleep mode, a power saving configuration is enabled by limiting the blocks that are supplied with power in contrast to standby mode. 
     Hereinafter, a description will be given of the above configuration in further detail. During standby mode, the function is enabled in which all blocks contained in the energized unit  215  during standby mode are supplied with power, and controlled by the central control unit  201 . When the central control unit  201  does not receive the operation input or receive a print job from the LAN  208  for at least a predetermined time period, the central control unit  201  shifts to sleep mode by detecting this situation by the sleep shift control unit  209 . During sleep mode, only blocks included in the energized unit  216  during sleep mode are caused to function. 
     During sleep mode, when the operation input detecting unit  211  detects the user operation, or when the LAN signal reception detecting unit  213  detects a specific packet originating from the LAN, the mode returns from sleep mode to standby mode. That is, in response to the above detection operations, the activation detection control unit  214  causes an activation signal for the central control unit  201  to operate, and the central control unit  201  supplies power again to all blocks included in the energized unit  215  during standby mode, and returns to standby mode. 
     The wireless LAN access point unit  204  is not energized during sleep mode, and is only energized during standby mode. That is, in the present embodiment, the wireless LAN access point unit  204  can function only during standby mode. 
     Next, a description will be given of the copying, scanning, and printing operations by the MFP  101  with reference to the system configuration diagram in  FIG. 1  and the block diagram of the MFP  101  in  FIG. 2 . Firstly, when the user performs a copying job, the user places a document to be copied on the reading unit  202 , and performs the copy operation by the operating unit  210 . The central control unit  201  detects the above operation, and causes the reading unit  202  to read the document, and transfer the read image data to the image processing unit  203  for image processing. Furthermore, the central control unit  201  causes the image data, that has been image processed in the image processing unit  203 , to be transferred to the printing unit  205  to thereby print the copy. 
     In addition, when the user performs a scan job, the user places a document to be scanned on the reading unit  202 , and transfers the scan data to the client PC  107  by operation of the operating unit  210 . The central control unit  201  detects the above operation, and causes the reading unit  202  to read the document, and transfer the read image data to the image processing unit  203  for image processing. Furthermore, the central control unit  201  transfers the image data that has been image processed to the LAN control unit  212 , and then transfers the data to the client PC  107  through the LAN  108 . 
     Furthermore, when the user performs a printing job from the client PC  107  on the MFP  101 , the user performs the following operations. Firstly, a direct print is printed immediately by the MFP  101  as a print job instructed from the client PC  107 . That is, the user creates a print job with the client PC  107 , and transfers the job through the LAN  108  to the MFP  101 . The central control unit  201  transfers the print job received through the LAN control unit  212  to the image processing unit  203 , and creates print data with RIP processing. The central control unit  201  transfers the print data to the printing unit  205  to perform printing of the print job. 
     In the present embodiment, the print job may be temporarily stored in the MFP  101 , and printed in a secure printing configuration to execute printing by input of password information for the job by the user. That is, the user creates a print job by provision through the client PC  107  of a job ID and password information, and transfers the job through the LAN control unit  108  to the MFP  101 . The central control unit  201  transfers the print job received through the LAN control unit  212  to the image processing unit  203  and creates print data by RIP processing. Then the central control unit  201  stores the print data in the image memory  207 . 
     At this time, the central control unit  201  stores the job ID and password information related to the stored print job in association with the job in the job managing unit  208 . Then, the user instructs printing by input of the job ID and password information through the operating unit  201  of the MFP  101 . When this operation is detected by the operating unit  210 , the central control unit  201  confirms a match with the password corresponding to the job Id in accordance with the information related to the job stored in the job managing unit  208 . The central control unit  201  transfers the print data stored in the image memory  207  to the printing unit  205  for performance of the print job. 
     Furthermore, in the present embodiment, a direct printing operation or secure printing operation can be performed from the mobile terminal  109 . A description will be given of the operation for performing a print job on the MFP  101  from the mobile terminal  109  with reference to the configuration illustrated in  FIG. 1  and the block diagram in  FIG. 2 . The direct print is printed immediately by the MFP  101  as a print job instructed from the mobile terminal  109 . That is, the user creates the print job with the mobile terminal  109 , selects the wireless LAN access point  101   a , and transfers the job to the MFP  101  through wireless LAN communication. The central control unit  201  transfers the print job received through the wireless LAN access point  101   a  to the image processing unit  203 , and creates print data through RIP processing. The central control unit  201  transfers the print data to the printing unit  205  to perform printing of the print job. 
     In this case, the print job from the mobile terminal  109  is temporarily stored in the MFP  101 , and may be printed in a secure printing configuration to execute printing by input of password information for the job by the user in the same manner as described the above. That is, the user creates a print job by provision through the mobile terminal  109  of a job ID and password information, selects the wireless LAN access point  101   a , and transfers the job through wireless LAN communication to the MFP  101 . The central control unit  201  transfers the print job received through the wireless LAN access point unit  204  to the image processing unit  203  and creates print data by RIP processing. Then the central control unit  201  stores the print data in the image memory  207 . 
     At this time, the central control unit  201  stores the job ID and password information related to the stored print job in association with the job in the job managing unit  208 . Then, the user instructs printing by input of the job ID and password information through the operating unit  201  of the MFP  101 . When the operating unit  210  detects this operation, the central control unit  201  checks the match with the password information corresponding to the job ID in accordance with the information related to the job that is stored in the job managing unit  208 . Then, the central control unit  201  transfers the print data stored in the image memory  207  to the printing unit  205  for performance of the print job. 
     Although, in the present embodiment, the performance of a copying job, scanning job, and printing job by the MFP  101  is described the above, execution of a copying job, scanning job, and printing job also can be applied to the MFP  102  to the MFP  104  as well. As described the above, in the present embodiment, depending on the type of job, a job may be executed immediately after receiving a job such as the direct printing job, or may be executed after temporary storage of a job received in the secure print configuration. 
     Next, a description will be given of a method for detecting a position of the mobile terminal  109  that is the wireless LAN terminal in the system consisting of the MFP apparatus that includes the wireless LAN function as illustrated in  FIG. 1 , with reference to  FIG. 3 . In the present embodiment, the method detecting the position of the mobile terminal  109  is based on a time difference of arrival (TDOA) method. In  FIG. 3 , three MFP apparatuses MFP  301 , MFP  302 , and MFP  303  are illustrated. The MFP  301 , MFP  302 , and MFP  303  illustrate three units of the MFP  101 , MFP  102 , MFP  103  and MFP  104  that are the plurality of MFP units illustrated in  FIG. 1 . 
     The wireless LAN access point  301   a , the wireless LAN access point  302   a , and the wireless LAN access point  303   a  respectively illustrate wireless LAN access points mounted on the MFP  301 , MFP  302 , and MFP  303 . In addition, a position-detection MFP-control server  303  corresponds to the position-detection MFP-control server  105  in  FIG. 1 , and a position detection master point  304  corresponds to the position detection master point  106  in  FIG. 1 . In the same manner, the LAN  305  corresponds to the LAN  108  in  FIG. 1 . The mobile terminal  306  corresponds to the mobile terminal  109  in  FIG. 1 . 
     Firstly, in advance of position detection, the geographic coordinate information of the MFP  301 , MFP  302 , and MFP  303  is recorded in the position-detection MFP-control server  303 . That is, the position of the MFP  301  is displayed as a coordinate 1:a, and in the same manner, the position of the MFP  302  is displayed as a coordinate 2:b, and the position of the MFP  303  is displayed as a coordinate 3:c, and this coordinate information is recorded in the position-detection MFP-control server  303 . Then position detection is performed by the position-detection MFP-control server  303  in accordance with the following method. 
     Firstly, the position-detection MFP-control server  303  instructs wireless sending of synchronous time information through the LAN  305  to the position detection master point  304 . In this manner, the wireless LAN access point  301   a , the wireless LAN access point  302   a , and the wireless LAN access point  303   a  receive the information in a wireless configuration, and cause the respective clocks provided therein to be synchronized to the received synchronous time. Then, the wireless LAN access point  301   a , the wireless LAN access point  302   a , and the wireless LAN access point  303   a  receive at the same time a wireless LAN signal that is sent in the wireless configuration from the mobile terminal  306 . 
     Here, the time at which the wireless LAN signal, that is sent in the wireless configuration from the mobile terminal  306 , is received by the wireless LAN access point  301   a  of the MFP  301  is denoted as 1:d. In the same manner, the reception time by the wireless LAN access point  302   a  of the MFP  302  is denoted as reception time 2:e, and the reception time by the wireless LAN access point  303   a  of the MFP  301  is denoted as reception time 3:f. The reception time information, the reception time 1:d, the reception time 2:e, and the reception time 3:f are respectively notified from the MFP  301 , the MFP  302 , and the MFP  303  through the LAN  305  to the position-detection MFP-control server  303 . 
     The difference in relation to the reception times at each wireless LAN access point is the result of the distance  307  of the mobile terminal  306  and the MFP  301 , the distance  308  of the mobile terminal  306  and the MFP  302 , and the distance  309  of the mobile terminal  306  and the MFP  303 . Therefore, the position-detection MFP-control server  303  can calculate the coordinate:X of the position of the mobile terminal  306  using a principle of trilateration with reference to the coordinate 1:a, the coordinate 2:b, the coordinate 3:c, the reception time 1:d, the reception time 2:e, and the reception time 3:f. The coordinate 1:a, the coordinate 2:b, and the coordinate 3:c represent coordinate information, and the reception time 1:d, the reception time 2:e, and the reception time 3:f represent reception time information. 
     As described the above, three wireless LAN access point positions must be used in the time difference of arrival (TDOA) method during position detection according to the present embodiment. That is, in order to detect the position of the mobile terminal, three MFPs must be configured in standby mode and the wireless LAN access points must be functioning. 
     Next, a description will be given of the operation of the system consisting of the MFP apparatus provided with the wireless LAN function according to the present embodiment in further detail below with reference to a flowchart based on the position-detection of the MFP apparatus as described the above. Firstly, a description will be given of the operation of advance settings for the position-detection MFP-control server  303  by a user with reference to the flowchart in  FIG. 4 . 
     Firstly a user prerecords the power consumption value of each MFP of the MFP  101 , MFP  102 , MFP  103  and MFP  104  as a power consumption profile in the position-detection MFP-control server  105 . Then, the power consumption profile recorded for each MFP is stored (set) in the position-detection MFP-control server  105  (S 4001 ). 
       FIG. 5  respectively illustrates power consumption during sleep mode and standby mode of each MFP of the MFP  101 , MFP  102 , MFP  103  and MFP  104  in the present embodiment. The power consumption values that are illustrated in  FIG. 5  are stored in the position-detection MFP-control server  105 . 
     Next, the user selects and sets whether or not to perform position detection of the mobile terminal  109  that is the wireless LAN terminal. The setting is stored in the position-detection MFP-control server  105  (S 4002 ). The user sets the coordinate information for each MFP of the MFP  101 , MFP  102 , MFP  103  and MFP  104  in the position-detection MFP-control server  105 . This coordinate information denotes the geographical coordinates of the MFP that are required for position detection of the mobile terminal  109  that is the wireless LAN terminal as described with reference to  FIG. 3 . The recorded coordinates for each MFP are stored (set) in the position-detection MFP-control server  105  (S 4003 ). With this manner, the setting of the position-detection MFP-control server  105  is completed. 
     Next, a description will be given of the operations during standby mode and sleep mode in the MFP  101 , the MFP  102 , the MFP  103  and the MFP  104  in detailed. Firstly, a description will be given of the operation for standby mode for the MFP  101 , the MFP  102 , the MFP  103  and the MFP  104  with reference to the block diagram illustrated in  FIG. 2  and the flowchart illustrated in  FIG. 6 . 
     Firstly, in S 6001 , the central control unit  201  determines whether or not a copy, scan, or print job has been received. More specifically, the central control unit  201  determines whether or not a user has operated the operating unit  210  to perform input of the copy job, or the scan job, or whether the LAN control unit  212  has received transfer of a print job from the LAN  108 . 
     In S 6001 , when the central control unit  201  determines that the job has not been received (“NO”), the determination is repeated until job is received. On the other hand, in S 6001 , when the central control unit  201  determines that the job has been received (“YES”), the processing proceeds to S 6002 . In S 6002 , the central control unit  201  determines whether or not the received job should be accumulated. More specifically, the central control unit  201  determines whether or not the received job is the secure print job. 
     In S 6002 , when the central control unit  201  determines that the job should be accumulated (“YES”), the processing proceeds to S 6003 . In S 6003 , the central control unit  201  accumulates the secure print job in the image memory  207 , and stores information for the job ID and the password information related to the accumulated print job in the job managing unit  208 . In addition, the central control unit  201  transfers the job ID for the accumulated secure print job in a configuration of job information to the LAN control unit  212 , and sends the job information through the LAN  108  to the position-detection MFP-control server  105 . 
     On the other hand, in S 6002 , when the central control unit  201  determines that the job should not be accumulated (“NO”), the processing proceeds to S 6004 . In S 6004 , the central control unit  201  determines that the received job is the job for immediate execution, and executes the copy job, scan job, or direct print job. 
     Next, in S 6005 , the central control unit  201  determines whether or not a notification indicating before the sleep shift has been received from the sleep shift control unit  209 . In the present embodiment, the central control unit  201  receives the notification from the sleep shift control unit  209  three minutes prior to the sleep shift setting time. In S 6005 , when the central control unit  201  determines that the notification indicating before the sleep shift has not been received (“NO”), the processing returns to S 6001 , and the central control unit  201  determines whether or not the job has been received. 
     On the other hand, in S 6005 , when the central control unit  201  determines that the notification indicating before the sleep shift has been received (“YES”), the processing proceeds to S 6006 . In S 6006 , the central control unit  201  transfers the notification indicating before the sleep shift to sleep to the LAN control unit  212  as a sleep shift prior notification, and sends the sleep shift prior notification through the LAN  108  to the position-detection MFP-control server  105 . 
     Next, in S 6007 , the central control unit  201  determines whether or not the sleep shift is authorized based on authorization or rejection information for the sleep shift received by the LAN control unit  212  through the LAN  108  from the position-detection MFP-control server  105 . In S 6007 , when the central control unit  201  determines that the sleep shift is not authorized based on the rejection information rather than the authorization information received from the position-detection MFP-control server  105  (“NO”), the processing proceeds to S 6008 . In S 6008 , the central control unit  201  does not shift to sleep, and resets the sleep timer of the sleep shift control unit  209 . Then, the processing returns to S 6001 , and the central control unit  201  determines whether or not the job has been received. 
     On the other hand, in S 6007 , when the central control unit  201  determines that the sleep shift is authorized based on the authorization information received from the position-detection MFP-control server  105  (“YES”), the processing proceeds to S 6009 . In S 6009 , the central control unit  201  resets the sleep timer of the sleep shift control unit  209 . Then in S 6010 , the central control unit  201  performs processing of sleep shift. More specifically, the central control unit  201  places the energized units other than the energized unit  216  during sleep mode among units of the energized unit  215  during standby mode illustrated in  FIG. 2  to the OFF position. In this manner, each MFP shifts to the sleep state. Thus, the operation during standby mode is completed. 
     Next, a description will be given of the operation for sleep mode for the MFP  101 , the MFP  102 , the MFP  103  and the MFP  104  with reference to the block diagram illustrated in  FIG. 2  and the flowchart illustrated in  FIG. 7 . As described above, during sleep mode, the respective units illustrated as the energized unit  216  during sleep mode in  FIG. 2  function by being energized. 
     Firstly, in S 7001 , the activation detection control unit  214  determines whether or not the activation instruction has been received from the position-detection MFP-control server  105 . That is, the LAN signal reception detecting unit  213  determines whether or not the activation packet addressed to its own device has been received through the LAN  108  from the position-detection MFP-control server  105 . In S 7001 , when the activation detection control unit  214  determines that the activation packet has been received (“YES”), the processing proceeds to S 7003 . 
     On the other hand, in S 7001 , when the activation detection control unit  214  determines that the activation packet has not been received (“NO”), the processing proceeds to S 7002 . In S 7002 , the activation detection control unit  214  determines whether or not the operation input detecting unit  211  detects an operation input by the user. In S 7002 , when the activation detection control unit  214  determines that the operation input detecting unit  211  detects the operation (“YES”), the processing proceeds to S 7003 . On the other hand, when the activation detection control unit  214  determines that the operation input detecting unit  211  does not detect the operation (“NO”), the processing returns to S 7001 . 
     Next, in S 7003 , when the activation detection control unit  214  detects the activation packet from the LAN signal reception detecting unit  213 , or detects the input operation from the operation input detecting unit  211 , the activation detection control unit  214  activates the central control unit  201 . In this manner, the central control unit  201  causes the units, which have been placed to the OFF position during sleep mode, among units of the energized units  215  during standby mode other than the energized unit  216  during sleep mode to be energized by placing to the ON position, to function again, and in this manner, the MFP shifts to standby mode. 
     Then, in S 7004 , the central control unit  201  transfers information (detection signal) for returning to standby from the LAN control unit  212  to the position-detection MFP-control server  105  through the LAN  108 . Next, in S 7005 , the central control unit  201  starts the sleep timer by controlling the sleep timer of the sleep shift control unit  209 . In this manner, the operations during sleep mode are completed. 
     Next, a description will be given of the operations of the position-detection MFP-control server  105  with reference to the flowchart in  FIG. 8 . Firstly, a description will be given of the operation of the position-detection MFP-control server  105  when a user sets position detection of the mobile terminal  109  that is the wireless LAN terminal, in S 4002 . 
     Firstly, in S 8001 , the position-detection MFP-control server  105  transfers (sends) the respective activation packets (mode switch signal) to the MFP  101 , the MFP  102 , the MFP  103 , and the MFP  104  through the LAN  108 . The MFP that is already in standby mode ignores the activation packet, and that MFP maintains standby mode. On the other hand, the MFP that is in sleep mode determines that the activation packet from the position-detection MFP-control server  105  has been detected in S 7001 , and proceeds to S 7003  to thereby return to the standby state. That is, at this point, all of the MFP  101 , the MFP  102 , the MFP  103 , and the MFP  104  are in the standby mode. Here, the position-detection MFP-control server  105  performs management by storing the state that the MFP  101 , the MFP  102 , the MFP  103 , and the MFP  104  are in the standby mode in the MFP management table. Although the MFP management table is not illustrated, the table is stored in an inner portion of the position-detection MFP-control server  105 . 
     Next, in S 8002 , the position-detection MFP-control server  105  performs position detection of the mobile terminal  109  that is the wireless LAN terminal. More specifically, the position detection is performed by the TDOA method by making use of the wireless LAN access points that are provided on the three MFPs of the MFP  101 , the MFP  102 , the MFP  103 , and the MFP  104  in accordance with the method described above in  FIG. 3 . 
     Next, in S 8003 , the position-detection MFP-control server  105  determines whether or not job information has been received from the MFP. That is, the position-detection MFP-control server  105  determines whether or not the job ID for the secure print job sent when the job is accumulated in S 6003  has been received through the LAN  108 . In S 8003 , when the position-detection MFP-control server  105  determines that the job ID has been received (“YES”), the processing proceeds to S 8005 . On the other hand, when the position-detection MFP-control server  105  determines that the job ID has not been received (“NO”), the processing proceeds to S 8004 . 
     In S 8004 , the position-detection MFP-control server  105  determines whether or not a standby return notification has been received from each MFP. That is, the position-detection MFP-control server  105  determines whether or not the standby return notification sent during standby return by each MFP in S 7004  has been received through the LAN  108 . In S 8004 , when the position-detection MFP-control server  105  determines that the standby return notification has been not received (“NO”), the processing proceeds to S 8006 . On the other hand, when the position-detection MFP-control server  105  determines that the standby return notification has been received (“YES”), the processing proceeds to S 8005 . 
     Next, in S 8005 , the job ID of the job accumulated in each MFP is stored and managed in the MFP management table based on the job information received in S 8003 . In addition, each MFP stores and manages the ascertained standby or sleep state of each MFP in the MFP management table based on the standby return notification received in S 8004 . 
     In S 8006 , the position-detection MFP-control server  105  determines whether or not the sleep shift notification has been received from any of the MFP  101 , the MFP  102 , the MFP  103  or the MFP  104 . That is, the position-detection MFP-control server  105  determines whether or not the sleep shift prior notification (power saving mode shift signal) sent by any MFP in S 6006  has been received through the LAN  108 . 
     In S 8006 , when the position-detection MFP-control server  105  determines that the sleep shift prior notification has not been received (“NO”), the processing returns to S 8002 , and position detection of the mobile terminal  109  is performed. On the other hand, when the position-detection MFP-control server  105  determines that the sleep shift prior notification has been received (“YES”), the processing proceeds to S 8007 . 
     In S 8007 , the position-detection MFP-control server  105  looks up the MFP management table that is retained in the inner portion of the server  105  to detect the standby or sleep mode state of each MFP being the MFP  101 , the MFP  102 , the MFP  103  or the MFP  104 . 
     Then, in S 8008 , the position-detection MFP-control server  105  looks up the management table to determine whether or not the number of MFPs in standby mode of the MFP  101 , the MFP  102 , the MFP  103  or the MFP  104  exceeds three units (the unit number N of MFPs is N&gt;3). That is, the position-detection MFP-control server  105  determines whether or not there are more than 3 available wireless LAN access points that are required for position detection of the mobile terminal  109  that is the wireless LAN terminal. 
     In S 8008 , when the position-detection MFP-control server  105  determines that there are more than 3 MFPs, of the MFP  101 , the MFP  102 , the MFP  103  or the MFP  104 , in standby mode (“YES”), the processing proceeds to S 8009 . More specifically, when the four MFPs being the MFP  101 , the MFP  102 , the MFP  103  or the MFP  104  are in the standby state, the determination in S 8008  is “YES”, and the processing proceeds to S 8009 . 
     Next, in S 8009 , the position-detection MFP-control server  105  sends the notification of authorization sleep shift through the LAN  108  to the MFP that has received the sleep shift prior notification in S 8006 . The notification of authorization sleep shift is received through the LAN  108  by the MFP that has received the sleep shift prior notification, and when the determination in S 6007  is “YES”, the MFP executes S 6009  and S 6010  to thereby shift to sleep mode. In S 8010 , the position-detection MFP-control server  105  updates, stores and manages the standby and sleep state of each MFP in the MFP table based on the authorization for sleep shift in S 8009 . 
     On the other hand, in S 8008 , when the position-detection MFP-control server  105  determines that there are not more than 3 MFPs in standby mode of the MFP  101 , the MFP  102 , the MFP  103  or the MFP  104  (“NO”), the processing proceeds to S 8011 . More specifically, when three of the MFPs being the MFP  101 , the MFP  102 , the MFP  103  or the MFP  104  are in a standby state, the determination in S 8008  is “NO”, and the processing proceeds to S 8011 . 
     Next, in S 8011 , the position-detection MFP-control server  105  looks up and detects the power consumption profile of each MFP that has been stored in S 4001 . In addition, the position-detection MFP-control server  105  looks up and detects the job information stored in each MFP and the standby and sleep state of each MFP with reference to the MFP management table stored in the inner portion of the server  105 . 
     Next, in S 8012 , the position-detection MFP-control server  105  compares the standby power consumption of the MFPs that are currently in the sleep mode state with the standby power consumption of the MFPs that received the sleep shift prior notification in S 8006  by looking up the MFP management table and the power consumption profile for each MFP. As a result, the MFP that has the smaller standby power consumption is specified and selected as one unit. 
     Next, in S 8013 , the position-detection MFP-control server  105  determines whether or not the MFP that has a smaller standby power consumption in S 8012  has been specified and selected. In S 8013 , when the position-detection MFP-control server  105  determines that any of the MFPs are selected (“YES”) in S 8012 , the processing proceeds to S 8016 . 
     On the other hand, in S 8013 , when the position-detection MFP-control server  105  determines that none of the MFPs are selected (“NO”) in S 8012 , the processing proceeds to S 8014 . More specifically, when the determination in S 8013  is “NO”, there is a configuration in S 8012  in which there is no difference in the standby power consumption between the MFPs that are currently in the sleep mode and the MFPs that have received the sleep shift prior notification in S 8006 . 
     Next, in S 8014 , the position-detection MFP-control server  105  looks up the MFP management table stored therein and specifies and selects an MFP that has both received the sleep shift prior notification and that stores more jobs that the MFPs that are currently in sleep mode as a single MFP. 
     In S 8015 , the position-detection MFP-control server  105  determines whether or not the MFP accumulating a higher number of jobs has been specified and selected. In S 8015 , when the position-detection MFP-control server  105  determines that any of the MFPs has been selected (“YES”), the processing proceeds to S 8016 . 
     On the other hand, in S 8015 , when the position-detection MFP-control server  105  determines that none of the MFPs has been selected (“NO”), the processing proceeds to S 8017 . More specifically, when the determination in S 8015  is “NO”, there is a configuration in S 8014  in which there is no difference in the job number that is accumulated by the MFPs that are currently in the sleep mode and the MFPs that have received the sleep shift prior notification in S 8006 . 
     Next, in S 8016 , the position-detection MFP-control server  105  determines whether or not the MFP selected in S 8013 , or S 8015  is the MFP that has received the sleep shift prior notification in S 8006 . In S 8016 , when the position-detection MFP-control server  105  determines that the MFP is an MFP that has received the sleep shift prior notification in S 8006  (“YES”), the processing proceeds to S 8017 . On the other hand, when the position-detection MFP-control server  105  determines that the MFP is not the MFP that has received the sleep shift prior notification in S 8006  (“NO”), the processing proceeds to S 8018 . 
     In S 8017 , the position-detection MFP-control server  105  sends the sleep shift rejection notification through the LAN  108  to the MFP that has received the sleep shift prior notification in S 8006 . In this manner, the MFP executes S 6008  as a result of the rejection to authorize sleep shift in S 6007 , and maintains the standby mode state. 
     In S 8018 , the position-detection MFP-control server  105  activates an MFP that is specified from the MFPs that are currently in the sleep mode state and that is not the MFP that has received the sleep shift prior notification. That is, the position-detection MFP-control server  105  sends the activation packet through the LAN  108  to such a MFP. The activation packet is received and detected by the MFP in S 7001 , and therefore, the result of S 7001  is “YES”, the processing steps in S 7003 , S 7004  and S 7006  are executed, and the MFP returns to the standby mode state. 
     Note that, in S 7004 , a standby return notification sent from the MFP through the LAN  108  is received, and thereafter, in S 8004 , the position-detection MFP-control server  105  determines the result of “YES”, and updates the MFP management table in S 8005 . Furthermore, the position-detection MFP-control server  105  sends the notification authorizing the sleep shift through the LAN  108  to the MFP that has received the sleep shift prior notification. 
     Next, in S 8019 , the MFP is determined by a result “YES” as being authorized to shift to sleep in the determination in S 6007 , and consequently, the processing steps in S 6009  and S 6010  are executed, and the MFP that has received a sleep shift prior notification shifts to the sleep mode state. 
     Then, in S 8020 , the position-detection MFP-control server  105  updates and stores the standby or sleep mode state of each MFP in the MFP management table that is stored therein. After execution of the processing steps in S 8017  and S 8020 , the position-detection MFP-control server  105  returns to S 8002  and performs position detection of the mobile terminal  109 . 
     According to the above, the processing steps in S 8011  to S 8020  enable the position-detection MFP-control server  105  to either maintain the standby mode for an MFP that has received the sleep shift prior notification, or to control another MFP that is in sleep mode to activate. Therefore, control is enabled to ensure that there are always three MFPs in the standby mode state of the MFP  101 , the MFP  102 , the MFP  103  and the MFP  104 . 
     Next, a description will be given of examples of control of the MFP  101 , the MFP  102 , the MFP  103  and the MFP  104  by the position-detection MFP-control server  105  in further detail making reference to  FIG. 9 .  FIG. 9  is a table illustrating the respective MFP states that are sent from each MFP (for example, mode state, detection signal for presence/absence of stored job), or the power consumption during standby. 
     Firstly, after activation of the MFP  101 , the MFP  102 , the MFP  103  and the MFP  104  in S 8001 , the power consumption profile and the MFP management table that is retained in the position-detection MFP-control server  105  is configured with a state of 1. That is, the power consumption during standby of the MFP  101 , the MFP  102 , the MFP  103  and the MFP  104  is respectively 60 W, 70 W, 100 W, and 100 W. Furthermore, the current mode (energized state) of all of the MFP  101 , the MFP  102 , the MFP  103  and the MFP  104  is the standby state. In addition, the MFP  101  has a job, job ID:1001. The MFP  103  has two jobs, job ID:3001 and job ID:3002. The MFP  102  and MFP  104  have no job. 
     In this context, when it is assumed that there is the sleep shift prior notification from the MFP  102  in S 8006  in the state 1, the configuration of the four MFPs in the standby state causes a result of “YES” in S 8008 , and the processing steps in S 8009  and S 8010  are executed. In this manner, the sleep mode shift of the MFP  102  is authorized and it transitions to a state 2. 
     In this context, when it is assumed that there is the sleep shift prior notification from the MFP  101  in S 8006  in the state 2, the configuration of the three MFPs in the standby state causes a result of “NO” in S 8008 . In this context, in S 8012 , when the standby power consumption of the MFP  101  and the MFP  102  is compared, the MFP  101  is specified since it is the MFP with the smaller standby power consumption. Consequently, the result of S 8013  becomes “YES”, and S 8016  becomes “YES”. In S 8017 , the sleep shift for the MFP  101  is rejected, and the MFP  101  maintains the standby mode state. Therefore, the state 2 is maintained without change. 
     On the other hand, when it is assumed that there is the sleep shift prior notification from the MFP  104  in S 8006  in the state 2, the configuration of the three MFPs in the standby state results in “NO” in S 8008 . In this context, in S 8012 , when the standby power consumption of the MFP  102  and the MFP  104  is compared, the MFP  102  is (preferentially) specified since it is the MFP with the relatively smaller standby power consumption. Consequently, the result of S 8013  becomes “YES”, and S 8016  becomes “NO”. In S 8018 , the MFP  102  is activated. Therefore, the sleep shift prior notification for the MFP  104  in S 8019  is authorized, and the MFP  104  shifts to sleep, and transitions to a state 3. 
     Next, when it is assumed that there is the sleep shift prior notification from the MFP  103  in S 8006  in the state 3, the configuration of the three MFPs in the standby state causes a result of “NO” in S 8008 . In this context, in S 8012 , when the standby power consumption of the MFP  103  and the MFP  104  is compared, there is no difference in the standby power consumption of the MFP  103  and the MFP  104 , and therefore, no MFP is specified, and S 8013  becomes “NO”. 
     Then, when the number of jobs stored in the MFP  103  and the MFP  104  is compared, the MFP  103  is (preferentially) specified since it is the MFP that stores a relatively larger number of jobs. Consequently, the result of S 8015  becomes “YES”, and S 8016  becomes “YES”. In S 8017 , the shift to sleep of the MFP  103  is rejected, and the MFP  103  maintains the standby mode state. Therefore the state 3 is maintained without change. 
     As described the above, in the control steps in S 8001  to S 8020  by the position-detection MFP-control server  105 , at least three MFPs are constantly configured in a standby mode state, and therefore the wireless LAN access points mounted on those MFPs are caused to function. As a result, the number of wireless LAN access points, that are required in S 8002  during position detection of the mobile terminal  109  that is the wireless LAN terminal, is always satisfied. 
     In S 8012 , the MFP that has the lower standby power consumption is selected and can be activated to the standby state, and therefore the system can operate on a lower power consumption. Furthermore, in S 8014 , the MFP that stores the higher number of jobs is activated to the standby state. Therefore, efficient operation of the system is enabled by preventing unnecessary sleep shift as a result of activating the MFP having the higher possibility of subsequent execution of printing in relation to the print job by the user. 
     In S 6005 , each MFP is configured to send the sleep shift prior notification three minutes prior to the sleep shift time, and therefore, the position-detection MFP-control server  105  performs sleep and standby control in relation to each MFP by detecting the sleep shift prior notification in S 8006 . Therefore, the position-detection MFP-control server  105  activates a MFP that is in a sleep state in S 8018 , and then can cause the MFP that has received the sleep shift prior notification to shift to sleep in S 8019 . 
     As a result, due to the fact that a sufficient time elapses after use is enabled in relation to the wireless LAN by energized to the wireless LAN access points of the MFP that is activated from the sleep state, the MFP that has received the sleep shift prior notification shifts to sleep, and the wireless LAN access point is placed in the OFF position. In this manner, when the handoff time during switching of the wireless LAN access points is considered, the required number (greater than or equal to a predetermined number) of the wireless LAN access points can be constantly operated. 
     Next, a description will be given of the operation of the position-detection MFP-control server  105  with reference to the flowchart in  FIG. 10  when a setting has been performed by the user in S 4002  to not execute position detection of the mobile terminal  109  that is the wireless LAN terminal. AS described the above, when the position-detection of the mobile terminal  109  is not performed, there is no requirement to always ensure the standby state in relation to three of the MFP  101 , the MFP  102 , the MFP  103  or the MFP  104 . 
     One of the wireless LAN access points  101   a  to  104   a  of the MFP  101 , the MFP  102 , the MFP  103  or the MFP  104  must function in order for the mobile terminal  109  to perform wireless LAN communication with the wireless LAN access points. As a result, in the present embodiment, control is performed so that the MFP  101  constantly maintains the standby state, and therefore at least one wireless LAN access point (the wireless LAN access point  101   a ) is configured in a functioning state. 
     Firstly, in S 10001 , the position-detection MFP-control server  105  forwards the activation packet to the MFP  101  through the LAN  108 . In this context, when the MFP  101  is already in standby mode, the activation packet is ignored, and the MFP maintains standby mode. On the other hand, when the MFP  101  is in sleep mode and it is determined that the activation packet from the position-detection MFP-control server  105  is detected, the processing proceeds to S 7003 , and the MFP returns to the standby state. 
     Next, in S 10002 , the position-detection MFP-control server  105  determines whether or not the sleep shift notification has been received from each MFP. That is, the position-detection MFP-control server  105  determines whether or not the sleep shift prior notification sent by each MFP in S 6006  has been received through the LAN  108 . In S 10002 , when the position-detection MFP-control server  105  determines that the sleep shift prior notification has not been received (“NO”), the determination is repeated until the sleep shift prior notification is received. On the other hand, in S 10002 , when the position-detection MFP-control server  105  determines that the sleep shift prior notification has been received (“YES”), the processing proceeds to S 10003 . 
     Next, in S 10003 , the position-detection MFP-control server  105  determines whether or not the sleep shift prior notification received in S 10002  is from the MFP  101 . In S 10003 , when the position-detection MFP-control server  105  determines that the sleep shift prior notification has been received from the MFP  101  (“YES”), the processing proceeds to S 10004 . On the other hand, in S 10003 , when the position-detection MFP-control server  105  determines that the sleep shift prior notification has not been received from the MFP  101  (“NO”), the processing proceeds to S 10005 . 
     In S 10004 , the position-detection MFP-control server  105  sends a notification rejecting sleep shift through the LAN  108  to the MFP  101  that received the sleep shift prior notification. In this manner, the MFP  101  rejects the non-authorized sleep shift in S 6007 , and executes the processing step in S 6008  to thereby maintain the standby mode state. 
     In S 10005 , the position-detection MFP-control server  105  sends the notification of authorization sleep shift to the MFP  101  through the LAN  108  that received the sleep shift prior notification. In this manner, that MFP is authorized to shift to sleep mode in S 6007 , and executes the processing steps in S 6009  and S 6010  to thereby shift to sleep mode. 
     After the processing steps in S 10004  and S 10005 , the position-detection MFP-control server  105  returns to S 10002  and repeats the determination of whether or not the sleep shift notification has been received. In the control of processing steps S 10001  to S 10005 , the position-detection MFP-control server  105  ignores job information sent from an MFP in S 6003  and standby return information sent from an MFP in S 7004 . 
     In this manner, in S 4002 , when a user performs a setting to not perform position detection of the mobile terminal  109  that is the wireless LAN terminal, the MFP  101  constantly maintains the standby state. On the other hand, the MFP  102 , the MFP  103  and the MFP  104  perform an independent determination in relation to sleep shift or returning to standby irrespective of an instruction from the position-detection MFP-control server  105 . 
     Therefore, the wireless LAN access point  101   a  mounted in the MFP  101  is constantly in operation, and although position detection of the mobile terminal  109  that is the wireless LAN terminal is not performed, wireless LAN communication by the wireless LAN access point  101   a  is constantly enabled. 
     Other Embodiments 
     Embodiments of the present invention can also be realized by a computer of a system or apparatus that reads out and executes computer executable instructions recorded on a storage medium (e.g., non-transitory computer-readable storage medium) to perform the functions of one or more of the above-described embodiment(s) of the present invention, 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). The computer may comprise one or more of a central processing unit (CPU), micro processing unit (MPU), or other circuitry, and may include a network of separate computers or separate computer processors. 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. 2013-182483, filed Sep. 3, 2013, which is hereby incorporated by reference herein in its entirety.