Abstract:
An image forming apparatus includes an operation accepter that accepts an operation of a user, and a hardware processor, wherein the hardware processor includes a user authenticator configured to authenticate the user who operates the operation accepter, a job executor configured to execute a job having an activation condition in response to satisfaction of the activation condition, a job receiver configured to receive a job, a state detector configured to, in the case where the job receiver receives the job having the activation condition from an information processing apparatus, detect a state of the authenticated user, and an activation condition changer configured to, in response to detection of a predetermined state by the state detector, change the activation condition.

Description:
[0001]    The present U.S. patent application claims a priority under the Paris Convention of Japanese patent application No. 2016-020563 filed on Feb. 5, 2016, the entirety of which is incorporated herein by reference. 
       BACKGROUND OF THE INVENTION 
     Field of the Invention 
       [0002]    The present invention relates to an image forming apparatus, a print control method, a non-transitory computer-readable recording medium encoded with a print control program. In particular, the present invention relates to an image forming apparatus, which a plurality of users can log in, a print control method performed in the image forming apparatus, and a non-transitory computer-readable recording medium encoded with the print control program. 
       Description of the Related Art 
       [0003]    A user who is located at a distant position from a Multi Function Peripheral (hereinafter referred to as an MFP) can instruct the MFP to print by using a portable information apparatus such as a personal computer (h e reinafter referred to as a “PC”), a smartphone or a tablet terminal. 
         [0004]    On the other hand, a technology for allowing the MFP, which is used by a plurality of persons, to display data is known. For example, in JP 2013-125551 A, an image forming apparatus that includes a touch panel display including an operation surface and a display surface, and a controller, wherein the controller controls the display of the touch panel display to show a desktop screen of each user with each outer edge of the panel of the touch panel display being a bottom of a display, and a direction from the outer edge of the panel towards a center of the panel being an upward direction. 
         [0005]    However, in the technology described in JP 2013-125551 A, because the plurality of persons can use the MFP, in the case where another user externally gives an instruction to execute a print job having a security setting, there is a problem that the print job cannot be executed since the MFP is in use. 
       SUMMARY OF THE INVENTION 
       [0006]    According to one aspect of the present invention, an image forming apparatus includes an operation accepter that accepts an operation of a user, and a hardware processor, wherein the hardware processor includes a user authenticator configured to authenticate the user who operates the operation accepter, a job executor configured to execute a job having an activation condition in response to satisfaction of the activation condition, a job receiver configured to receive a job, a state detector configured to, in the case where the job receiver receives the job having the activation condition from an information processing apparatus, detect a state of the authenticated user, and an activation condition changer configured to, in response to detection of a predetermined state by the state detector, change the activation condition. 
         [0007]    According to another aspect of the present invention, a print control method performed in an image forming apparatus including an operation acceptor that accepts an operation of a user includes a user authentication step of authenticating the user who operates the operation acceptor, a job execution step of executing a job having an activation condition in response to satisfaction of the activation condition, a job reception step of receiving the job, a state detection step of, in the case where the job having the activation condition is received from an information processing apparatus in the job reception step, detecting a state of the authenticated user, and an activation condition changing step of, in response to detection of a predetermined state in the state detection step, changing the activation condition. 
         [0008]    According to yet another aspect of the present invention, a non-transitory computer-readable recording medium encoded with a print control program executed by a computer, which controls an image forming apparatus including an operation acceptor that accepts an operation of a user, wherein the print control program causes the computer to perform a user authentication step of authenticating the user who operates the operation acceptor, a job execution step of executing a job having an activation condition in response to satisfaction of the activation condition, a job reception step of receiving a job, a state detection step of, in the case where the job having the activation condition is received from an information processing apparatus in the job reception step, detecting a state of the authenticated user, and an activation condition changing step of, in response to detection of a predetermined state in the state detection step, changing the activation condition. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    The above and other objects, advantages and features of the present invention will become more fully understood from the detailed description given herein below and the appended drawings which are given by way of illustration only, and thus are not intended as a definition of the limits of the present invention, and wherein: 
           [0010]      FIG. 1  is a diagram showing one example of an overview of a print system in one embodiment of the present invention; 
           [0011]      FIG. 2  is a perspective view showing an appearance of an MFP in the one embodiment of the present invention; 
           [0012]      FIG. 3  is a block diagram showing an outline of a hardware configuration of an MFP; 
           [0013]      FIG. 4  is a block diagram showing one example of a hardware configuration of a PC; 
           [0014]      FIG. 5  is a diagram showing one example of functions of a CPU of the MFP; 
           [0015]      FIG. 6  is a plan view showing a display surface of a display unit; 
           [0016]      FIG. 7  is a diagram showing one example of a designated user selection screen; 
           [0017]      FIG. 8  is a diagram showing one example of a request screen; 
           [0018]      FIG. 9  is a first flow chart showing one example of a flow of a print control process; 
           [0019]      FIG. 10  is a second flow chart showing the one example of the flow of the print control process; and 
           [0020]      FIG. 11  is a flow chart showing one example of a flow of a job production process. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0021]    Hereinafter, an embodiment of the present invention will be described with reference to the drawings. However, the scope of the invention is not limited to the illustrated examples. 
         [0022]    In the following description, the same parts are denoted with the same reference characters. Their names and functions are also the same. Thus, a detailed description thereof will not be repeated. 
         [0023]      FIG. 1  is a diagram showing one example of an overview of a print system in one embodiment of the present invention. Referring to  FIG. 1 , the print system  1  includes an MFP (a Multi Function Peripheral)  100  and personal computers (hereinafter referred to as “PCs”)  200 ,  200 A. The MFP  100  and the PCs  200 ,  200 A are respectively connected to a network  3  and can communicate with one another via the network  3 . Further, the network  3  is connected to the internet, and the MFP  100  and the PCs  200 ,  200 A can respectively communicate with another computer connected to the internet. 
         [0024]    A driver program for controlling the MFP  100  is installed in each of the PCs  200 ,  200 A, and each of the PCs  200 ,  200 A can transmit a print job including print data to the MFP  100  and allow the MFP  100  to form an image of the print data. The PCs  200 ,  200 A respectively have the same basic hardware configuration and functions. Thus, the PC  200  will be taken as an example in the description here, unless otherwise specified. While the PC  200  is described here as the example, it may be a computer carried and used by a user such as a smartphone, a tablet terminal and a PDA (Personal Digital Assistants) as long as a print driver for controlling the MFP  100  is installed therein. 
         [0025]      FIG. 2  is a perspective view showing the appearance of the MFP in the one embodiment of the present invention.  FIG. 3  is a block diagram showing an outline of the hardware configuration of the MFP. Referring to  FIGS. 2 and 3 , the MFP (Multi Function Peripheral)  100  is one example of an image forming apparatus and includes a main circuit  110 , a display unit  120 , a touch panel  130 , cameras  140 A to  140 D, a document scanning unit  150  for scanning a document, an image forming unit  160  for forming an image on a sheet of paper or other medium based on image data output by the document scanning unit  150  scanning a document, and a paper feed unit  170  for supplying a sheet of paper to the image forming unit  160 . 
         [0026]    The main circuit  110  includes a CPU (Central Processing Unit)  111 , a communication I/F (interface) unit  112 , a ROM (Read Only Memory)  113 , a RAM (Random Access Memory)  114 , an EEPROM (Electrically Erasable and Programmable ROM)  115 , an HDD (Hard Disk Drive)  116  as a mass storage device, a facsimile unit  117 , and an external storage device  118  on which a CD-ROM (Compact Disk-ROM)  118 A is mounted. The CPU  111  is connected to the display unit  120 , the touch panel  130 , the cameras  140 A to  140 D, the document scanning unit  150 , the image forming unit  160  and the paper feed unit  170  to control the entire MFP  100 . 
         [0027]    The display unit  120  is a display device such as an LCD (Liquid Crystal Display) or an organic ELD (Electro-Luminescence Display). The display unit  120  is arranged in an upper portion of a main body of the MFP  100  with a display surface on which an image is displayed facing upward. The display unit  120  is connected to the main body of the MFP  100  to be turnable with respect to one edge of the display surface and can be opened and closed. The document scanning unit  150  is arranged below the display unit  120 , and a scan surface with which the document scanning unit  150  scans a document is exposed with the display unit  120  turned and opened. The display unit  120  is controlled by the CPU  111  and displays an image. 
         [0028]    The touch panel  130  is provided on an upper surface or a lower surface of the display unit  120 . The touch panel  130  detects a position on the display surface of the display unit  120  designated by the user. The touch panel  130  outputs coordinates of the detected position to the CPU  111 . 
         [0029]    The CPU  111  specifies a position in an image displayed in the display unit  120  from the position on the display surface of the display unit  120  detected by the touch panel  130  and detects an operation by the user. For example, in the case where a keyboard is displayed in the display unit  120 , if a position detected by the touch panel  130  is within an image of any key of the keyboard, the CPU  111  detects an operation of giving an instruction for the input of the key. 
         [0030]    The cameras  140 A to  140 D are respectively installed at side surfaces, facing in four directions, of the main body of the MFP  100 . Specifically, the camera  140 A is provided at a left side surface of the MFP  100 , the camera  140 B is provided at a back surface of the MFP  100 , the camera  140 C is provided at a right side surface of the MFP  100 , and the camera  140 D is provided at a front surface of the MFP  100 . Each of the cameras  140 A to  140 D picks up an image of a photographic subject, acquires image data and outputs the image data to the CPU  111 . The case where the camera  140 A picks up an image of a user A, the camera  140 B picks up an image of a user B, and the camera  140 C picks up an image of a user C will be described here as an example. 
         [0031]    The ROM  113  stores a program that is executed by the CPU  111  or data necessary for execution of the program. The RAM  114  is used as a work area when the CPU  111  executes the program. 
         [0032]    The communication I/F unit  112  is an interface for connecting the MFP  100  to the network  3 . The CPU  111  communicates with a computer connected to the network  3  via the communication I/F unit  112  and receives data from and transmits data to the computer. Further, the communication I/F unit  112  can communicate with a computer connected to the internet via the network  3 . 
         [0033]    The facsimile unit  117  is connected to a PSTN (Public Switched Telephone Network) and transmits and receives facsimile data. The facsimile unit  117  converts the image data scanned by the document scanning unit  150  or the data stored in the HDD  116  into facsimile data and transmits the facsimile data to a facsimile device connected to the PSTN. Further, the facsimile unit  117  stores the received facsimile data in the HDD  116  or allows the image forming unit  160  to form an image of the facsimile data on a sheet of paper. 
         [0034]    The external storage device  118  is mounted with the CD-ROM  118 A. The CPU  111  can access the CD-ROM  118 A via the external storage device  118 . The CPU  111  loads a program recorded in the CD-ROM  118 A, which is mounted on the external storage device  118 , into the RAM  114  for execution. The program that is executed by the CPU  111  is not limited to the program recorded in the CD-ROM  118 A, and a program stored in the HDD  116  may be loaded into the RAM  114  for execution. In this case, another computer connected to the network  3  may rewrite the program stored in the HDD  116  of the MFP  100 , or may additionally write a new program therein. Further, the MFP  100  may download a program from another computer connected to the network  3  and store the program in the HDD  116 . The program referred to here includes not only a program directly executable by the CPU  111  but also a source program, a compressed program, an encrypted program or the like. 
         [0035]    In  FIG. 2 , the case where the three users A, B, C who attend a conference are using the MFP  100  in the conference is shown as an example. The user A is positioned in the vicinity of the left side surface of the MFP  100 , the user B is positioned in the vicinity of the back surface of the MFP  100 , and the user C is positioned in the vicinity of the right side surface of the MFP  100 . In this case, the camera  140 A outputs a picked-up image of the user A to the CPU  111 , the camera  140 B outputs a picked-up image of the user B to the CPU  111 , and the camera  140 C outputs a picked-up image of the user C to the CPU  111 . 
         [0036]    During the conference in which the users A, B, C are using the MFP  100 , in the case where a user E who operates the PC  200  transmits a job having a security setting to the MFP  100 , the user E cannot use the MFP  100 , thereby not being able to execute the job. The job having the security setting is the job having authentication of the user E by the MFP  100  set as an activation condition. In the case where the MFP  100  receives the job having the activation condition, the MFP  100  does not execute the received job immediately but executes the received job on the condition that the user E is authenticated by the MFP  100 . In the case where the user E who operates the PC  200  transmits the job having the security setting to MFP  100  during the conference in which the users A, B, C are using the MFP  100 , the MFP  100  in the present embodiment can execute the job. 
         [0037]      FIG. 4  is a block diagram showing one example of a hardware configuration of the PC. Referring to  FIG. 4 , the PC  200  includes a CPU  201  for controlling the entire PC  200 , a ROM  202  for storing a program to be executed by the CPU  201 , a RAM  203  that is used as a work area of the CPU  201 , an HDD  204  for storing data in a non-volatile manner, a communication unit  205  for connecting the CPU  201  to the network  3 , a display unit  206  for displaying information, an operation unit  207  for accepting input of operations by the user, and an external storage device  209 . 
         [0038]    The external storage device  209  is mounted with a CD-ROM  209 A. While an example where the CPU  201  executes a program stored in the ROM  202  is described in the present embodiment, the CPU  201  may control the external storage device  209 , read out the program to be executed by the CPU  201  from the CD-ROM  209 A, and store the read program in the RAM  203  for execution. 
         [0039]    A recording medium for storing the program to be executed by the CPU  201  is not limited to the CD-ROM  209 A but may be a flexible disk, a cassette tape, an optical disk (MO/MD/DVD), an IC card, an optical card, or a semiconductor memory such as a mask ROM, an EPROM, or an EEPROM. Further, the CPU  201  may download a program from a computer connected to the network  3  and store the program in the HDD  204 , or the computer connected to the network may write the program in the HDD  204 . Then, the program stored in the HDD  204  may be loaded into the RAM  203  to be executed by the CPU  201 . The program referred to here includes not only a program directly executable by the CPU  201  but also a source program, a compressed program, an encrypted program and the like. 
         [0040]      FIG. 5  is a diagram showing one example of the functions of the CPU included in the MFP. The functions shown in  FIG. 5  are the functions formed in the case where the CPU  111  included in the MFP  100  executes a print control program stored in the ROM  113 , the EEPROM  115 , the HDD  116  or the CD-ROM  118 A. Referring to  FIG. 5 , the CPU  111  includes an operation acceptance portion  51  that accepts an operation by the user, a process execution portion  53  that executes a process in accordance with the accepted operation, a display control portion  55  that controls the display unit  120 , a user authentication portion  59  that authenticates the user, a state detection portion  57  that detects a state of the authenticated user, a job reception portion  61  that receives a job, a job execution portion  65  that executes the received job, and an activation condition changing portion  63 . 
         [0041]    The user authentication portion  59  authenticates the user and determines a position of the authenticated user. The user authentication portion  59  authenticates the user by facial authentication based on an image received from each of the cameras  140 A to  140 D. The MFP  100  stores the authentication information of a user who is permitted to use the MFP  100  in advance. The authentication information is a set of user identification information for identifying the user and feature information that is extracted from the picked-up facial image of the user. The feature information includes the collection of feature points that constitute a shape of each part in the facial image and information such as color of each part and the like. The user authentication portion  59  performs the facial authentication by using the feature information extracted from an image received from any of the cameras  140 A to  140 D and the feature information included in the authentication information stored in the HDD  116 . Specifically, in the case where extracting a region in which a face is shown from an image received from the camera  140 A, for example, the user authentication portion  59  extracts the feature information from the extracted region. Then, in the case where the authentication information including the feature information that matches the extracted feature information is stored in the HDD  116 , the user authentication portion  59  authenticates the user A. 
         [0042]    Further, in the case where authenticating the user, the user authentication portion  59  determines a position of the user based on a position where a camera that has picked up an image of the authenticated user among the cameras  140 A to  140 D is arranged. In the case where authenticating the user based on the image output by the camera  140 A, the user authentication portion  59  determines that the position of the authenticated user is in the vicinity of the left side surface of the MFP  100 . In the case where authenticating the user based on an image output by the camera  140 B, the user authentication portion  59  determines that a position of the authenticated user is in the vicinity of the back surface of the MFP  100 . In the case where authenticating the user based on an image output by the camera  140 C, the user authentication portion  59  determines that a position of the authenticated user is in the vicinity of the right side surface of the MFP  100 . In the case where authenticating the user based on an image output by the camera  140 D, the user authentication portion  59  determines that a position of the authenticated user is in the vicinity of the front surface of the MFP  100 . Thus, the maximum number of users to be simultaneously permitted to log in by the user authentication portion  59  is four. 
         [0043]    In the present embodiment, because the camera  140 A picks up the image of the user A, in the case where the user authentication portion  59  authenticates the user A, it is determined that the position of the user A is in the vicinity of the left side surface of the MFP  100 . Because the camera  140 B picks up the image of the user B, in the case where the user authentication portion  59  authenticates the user B, it is determined that the position of the user B is in the vicinity of the back surface of the MFP  100 . Because the camera  140 C picks up the image of the user C, in the case where the user authentication portion  59  authenticates the user C, it is determined that the position of the user C is in the vicinity of the right side surface. 
         [0044]    When the user is authenticated, the user authentication portion  59  outputs a set of the user identification information of the authenticated user and position information indicating the position of the detected user to the operation acceptance portion  51 , the process execution portion  53 , the job execution portion  65  and the state detection portion  57 . 
         [0045]    The display control portion  55  controls the display unit  120  and allows the display unit  120  to display an image. A display surface of the display unit  120  includes a first personal display region, a second personal display region, a third personal display region, a fourth personal display region, and a common region commonly used among the four users. 
         [0046]      FIG. 6  is a plan view showing the display surface of the display unit. Referring to  FIG. 6 , the display surface of the display unit  120  includes the first personal display region  121 , the second personal display region  122 , the third personal display region  123 , the fourth personal display region  124  and the common region  125 . The first personal display region  121  is positioned in the vicinity of an edge close to the left side surface of the MFP  100  among four edges of the display surface. The second personal display region  122  is positioned in the vicinity of an edge close to the back surface of the MFP  100  among the four edges of the display surface. The third personal display region  123  is positioned in the vicinity of an edge close to the right side surface of the MFP  100  among the four edges of the display surface. The fourth personal display region  124  is positioned in the vicinity of an edge close to the front surface among the four edges of the display surface. The common region  125  is positioned at the center of the display surface. 
         [0047]    Returning to  FIG. 5 , based on the set of the user identification information and the position information received from the user authentication portion  59 , the operation acceptance portion  51  associates the user specified by the user identification information with any one of the first personal display region  121 , the second personal display region  122 , the third personal display region  123  and the fourth personal display region  124 . The operation acceptance portion  51  associates the user, whose user identification information is associated with the position information indicating the position in the vicinity of the left side surface, with the first personal display region  121 , associates the user, whose user identification information is associated with the position information indicating the position in the vicinity of the back surface, with the second personal display region  122 , associates the user, whose user identification information is associated with the position information indicating the position in the vicinity of the right side surface, with the third personal display region  123 , and associates the user, whose user identification information is associated with the position information indicating the position in the vicinity of the front surface, with the fourth personal display region  124 . 
         [0048]    The operation acceptance portion  51  accepts an operation by the user based on the position in the display surface of the display unit  120  detected by the touch panel  130 . Specifically, in the case where a position in the first personal display region  121  is detected by the touch panel  130 , the operation acceptance portion  51  accepts the operation as the operation by the user A associated with the first personal display region  121  based on the detected position. In the case where a position in the second personal display region  122  is detected by the touch panel  130 , the operation acceptance portion  51  accepts the operation as the operation by the user B associated with the second personal display region  122  based on the detected position. In the case where a position in the third personal display region  123  is detected by the touch panel  130 , the operation acceptance portion  51  accepts the operation as the operation by the user C associated with the third personal display region  123  based on the detected position. In the case where a position in the common region  125  is detected by the touch panel  130 , the operation acceptance portion  51  accepts the operation based on the detected position. However, the operation acceptance portion  51  does not determine a subject (a person) who has performed the operation. In the case where accepting the operation, if determining the subject (person) who has performed the operation, the operation acceptance portion  51  outputs the user identification information of the determined user to the process execution portion  53 . 
         [0049]    The operations that are accepted by the operation acceptance portion  51  include an operation of designating data that is to be a target of a process, an operation of editing data that is to be a target of a process, and an operation of deleting data that is to be a target of a process, for example. For example, with the display control portion  55  displaying a data designation acceptance screen that lists pieces of data identification information for identifying data in the display unit  120 , in response to detection by the touch panel  130  of a position in the image in which the data identification information is displayed, the operation acceptance portion  51  accepts the operation of designating the data specified by the data identification information displayed at the detected position. In the case where accepting the operation of designating data, the operation acceptance portion  51  outputs a read instruction including the data identification information displayed at the position detected by the touch panel  130  to the process execution portion  53 . 
         [0050]    The process execution portion  53  executes a process in accordance with an operation accepted by the operation acceptance portion  51 . In response to reception of the read instruction from the operation acceptance portion  51 , the process execution portion  53  acquires the data specified by the data identification information included in the read instruction. In the case where receiving the user identification information from the operation acceptance portion  51 , when acquiring the data in accordance with the read instruction, the process execution portion  53  acquires the data within a range of access permission of the user specified by the user identification information received from the operation acceptance portion  51 . The access permission is the right to access the data. For example, three levels including the highest level  1 , the intermediate level  2  and the lowest level  3  are defined. In the case where the level  2  is provided to the user A, the user A cannot access and read the data provided with the level  1  with his/her access permission. However, the user A can access and read the data provided with the level  2  or the level  3 . 
         [0051]    In the case where the data specified by the data identification information is stored in the HDD  116 , the process execution portion  53  reads out the data specified by the data identification information from the HDD  116 . In the case where the data specified by the data identification information is stored in an external information processing apparatus, the process execution portion  53  controls the communication I/F unit  112  and acquires the data specified by the data identification information from the external computer. In the case where the data specified by the data identification information is stored in the CD-ROM  118 A, the process execution portion  53  controls the external storage device  118  and reads out the data specified by the data identification information from the CD-ROM  118 A. The process execution portion  53  outputs the acquired data to the display control portion  55 . The display control portion  55  displays an image of the data received from the process execution portion  53  in the display unit  120 . 
         [0052]    Further, when a position in the image of the data displayed in the display unit  120  by the display control portion  55  is detected by the touch panel  130 , the operation acceptance portion  51  specifies the data that is a target of a process. For example, the operation acceptance portion  51  outputs a display instruction to the display control portion  55  and allows the display control portion  55  to display an operation acceptance screen in the display unit  120 . The operation acceptance screen includes a button to which an operation is assigned. When a position within the button included in the operation acceptance screen is detected by the touch panel  130 , the operation acceptance portion  51  accepts the operation assigned to the button. When specifying the data that is the target of the process, the operation acceptance portion  51  outputs a set of the data identification information for identifying data and the operation accepted by the touch panel  130  to the process execution portion  53 . 
         [0053]    In response to reception of the set of the data identification information and the operation from the operation acceptance portion  51 , the process execution portion  53  processes the data specified by the data identification information in accordance with the operation received from the operation acceptance portion  51 . For example, in the case where the operation received from the operation acceptance portion  51  is an operation of editing, the process execution portion  53  edits the data and outputs a data display instruction including the edited data to the display control portion  55 . In response to reception of the data display instruction from the process execution portion  53 , the display control portion  55  displays an image of the updated data included in the data display instruction in the display unit  120 . In the case where the operation received from the operation acceptance portion  51  is an operation of deleting the data, the process execution portion  53  erases the data specified by the data identification information and outputs an erasure instruction including the data identification information to the display control portion  55 . In response to the reception of the erasure instruction, the display control portion  55  ends the display of the image of the data specified by the data identification information included in the erasure instruction among the images displayed in the display unit  120 . 
         [0054]    The job reception portion  61  controls the communication I/F unit  112 , receives a job, outputs the received job to the activation condition changing portion  63  and the job execution portion  65 , and outputs a detection instruction to the state detection portion  57 . The detection instruction includes device identification information of a device that has transmitted the job. The case where the job reception portion  61  receives a job having the activation condition from the PC  200  will be described here as an example. The activation condition is a condition for executing a job. The activation condition set here is that a user who has given an instruction to execute a job is authenticated. In this case, the activation condition includes the user identification information for identifying the user who has given an instruction to execute the job. 
         [0055]    The job execution portion  65  executes the job received from the job reception portion  61 . In the case where the activation condition is set for the job received from the job reception portion  61 , the job execution portion  65  does not execute the job immediately but executes the job on the condition that the activation condition is satisfied. Because the activation condition is that the user who has given an instruction to execute the job is authenticated, in response to reception of the user identification information that is the same as the user identification information included in the activation condition from the user authentication portion  59 , the job execution portion  65  executes the job. Specifically, the job execution portion  65  controls the image forming unit  160  and allows the image forming unit  160  to form an image of the print data included in the job. 
         [0056]    The state detection portion  57  receives a set of the user identification information and the position information of the user authenticated from the user authentication portion  59 . In the case where a plurality of users are authenticated by the user authentication portion  59 , the state detection portion  57  receives sets of the user identification information and the position information of all of the plurality of authenticated users. In response to reception of the detection instruction from the job reception portion  61 , the state detection portion  57  detects a state of the user who is authenticated at that time point. The state detection portion  57  includes a notification portion  71 , a designated user acceptance portion  73 , a request portion  75 , and a response acceptance portion  77 . In response to the reception of the detection instruction, the notification portion  71  notifies a device specified by the device identification information included in the detection instruction of the user who has been authenticated by the user authentication portion  59 . Because the PC  200  transmits a job, the detection instruction includes the device identification information of the PC  200 . In this case, the notification portion 71  controls the communication I/F unit  112 , transmits the user identification information received from the user authentication portion  59  to the PC  200 , and outputs an acceptance instruction to the designated user acceptance portion  73 . In the case where a plurality of pieces of user identification information are received from the user authentication portion  59 , the notification portion  71  transmits all of the plurality of pieces of identification information to the PC  200 . 
         [0057]    The PC  200 , which receives the user identification information from the MFP  100 , displays a designated user selection screen based on the user identification information received from the MFP  100 , and accepts an operation of inputting in accordance with the designated user selection screen and selecting the designated user by the user. In response to acceptance of the operation of selecting the designated user, the PC  200  sets the selected user identification information as the user identification information of the designated user, and transmits the user identification information of the designated user to the MFP  100 . 
         [0058]      FIG. 7  is a diagram showing one example of the designated user selection screen. Referring to  FIG. 7 , the designated user selection screen is a screen that displays the user identification information for identifying the user who is logged in the MFP  100  in a selectable manner. Specifically, the designated user selection screen is a screen where the pieces of user identification information “User A”, “User B” and “User C” are arranged, and includes check boxes arranged at the left of each of the pieces of user identification information “User A”, “User B” and “User C”. An operation of selecting the designated user by the user is an operation of selecting the check box. 
         [0059]    Returning to  FIG. 5 , in response to reception of the acceptance instruction, the designated user acceptance portion  73  accepts the designated user. The designated user is a user selected by the user who operates the PC  200  among one or more users authenticated by the user authentication portion  59 . Specifically, when the communication I/F unit  112  receives the user identification information from the PC  200 , the designated user acceptance portion  73  accepts the user specified by the received user identification information as the designated user. The designated user acceptance portion  73  outputs the user identification information, which the communication I/F unit  112  receives from the PC  200 , to the request portion  75  as the user identification information of the accepted designated user. 
         [0060]    In response to reception of the user identification information of the designated user from the designated user acceptance portion  73 , the request portion  75  requests the designated user to execute the job and outputs the acceptance instruction to the response acceptance portion  77 . Specifically, the request portion  75  displays a request screen for requesting the execution of the job in the display unit  120 . 
         [0061]      FIG. 8  is a diagram showing one example of the request screen. Referring to  FIG. 8 , the request screen  300  includes a message  301  ““User E” has requested the execution of the job. Do you want to accede to the request?” and an acceding button  302  for giving an instruction to accede to the request, and a declining button for giving an instruction to decline the request. 
         [0062]    Returning to  FIG. 5 , a region in which the request portion  75  displays the request screen  300  is a region corresponding to the position specified by the position information that makes a set with the user identification information of the designated user in the display surface of the display unit  120 . Specifically, in the case where the designated user is the user A, the request portion  75  displays the request screen in the first personal display region  121  corresponding to the user A. In the case where the designated user is the user B, the request portion  75  displays the request screen in the second personal display region  122  corresponding to the user B. In the case where the designated user is the user C, the request portion  75  displays the request screen in the third personal display region  123  corresponding to the user C. 
         [0063]    When a position within the acceding button  302  in the request screen displayed in the display unit  120  is detected by the touch panel  130 , the operation acceptance portion  51  accepts an operation of acceding to the request, and outputs an acceding signal to the response acceptance portion  77 . When a position within the declining button  303  is detected by the touch panel  130 , the operation acceptance portion  51  accepts an operation of declining the request and outputs a declining signal to the response acceptance portion  77 . 
         [0064]    In response to the reception of the acceding signal from the operation acceptance portion  51  after the reception of the acceptance instruction from the request portion  75 , the response acceptance portion  77  outputs a change instruction to the activation condition changing portion  63  and transmits an acceding notification to the PC  200 . The acceding notification includes a message indicating that the designated user has acceded to the request. The PC  200 , which receives the acceding notification, displays the message included in the acceding notification. Thus, the user who operates the PC  200  can be informed of the acceding of the request by the designated user. The change instruction includes the user identification information of the designated user. In response to the acceptance of the operation of declining the request by the operation acceptance portion  51  after the reception of the acceptance instruction from the request portion  75 , the response acceptance portion  77  does not output the change instruction to the activation condition changing portion  63  and returns a declining notification to the PC  200 . The declining notification includes a message indicating that the request has been declined. The PC  200 , which receives the declining notification, displays the message included in the declining notification. Thus, the user who operates the PC  200  can be informed of the declining of the request by the designated user. 
         [0065]    In response to reception of the change instruction from the response acceptance portion  77 , the activation condition changing portion  63  changes the activation condition set for the job received from the job reception portion  61 . Specifically, the authentication of the user who has given an instruction to execute the job, which is set as the activation condition included in the job, is changed to authentication of the designated user. The activation condition changing portion  63  outputs the job having the changed activation condition to the job execution portion  65 . 
         [0066]    In the case where receiving a job from the activation condition changing portion  63 , the job execution portion  65  executes the job received from the activation condition changing portion  63  and erases the same job received from the job reception portion  61 . Because the designated user specified by the user identification information included in the activation condition has already been authenticated by the user authentication portion  59 , in response to the reception of the job from the activation condition changing portion  63 , the job execution portion  65  executes the job. Further, because the activation condition is changed, on the condition that the designated user, specified by the user identification information included in the activation condition included in the job received from the activation condition changing portion  63 , is authenticated again by the user authentication portion  59 , the job execution portion  65  may execute the job. 
         [0067]      FIGS. 9 and 10  are flow charts showing one example of a flow of a conference assistance process. The conference assistance process is a process that is executed by the CPU  111  in the case where the CPU  111  included in the MFP  100  executes a conference assistance program stored in the ROM  113 , the EEPROM  115 , the HDD  116  or the CD-ROM  118 A. Referring to  FIGS. 9 and 10 , the CPU  111  determines whether the user has been authenticated (step S 01 ). If the user is authenticated, the process proceeds to the step S 02 . If not, the process proceeds to the step S 12 . The user is authenticated by the facial authentication based on the image received from each of the cameras  140 A to  140 D. For example, in the case where a region in which a face is shown is extracted from the image received from the camera  140 D, the feature information is extracted from the extracted region. Then, in the case where the authentication information including the feature information that matches the extracted feature information is stored in the HDD  116 , the user, who is specified by the user identification information included in the authentication information including the feature information that matches the extracted feature information, is authenticated. 
         [0068]    In the step S 02 , the authenticated user is permitted to log in, and the process proceeds to the step S 03 . In the step S 03 , a position of the user is detected. The position of the user is determined based on the position at which the camera which has picked up an image of the authenticated user among the camera  140 A to  140 D is arranged. Specifically, in the case where the user is authenticated based on an image output by the camera  140 A, the CPU  111  determines that the position of the authenticated user is in the vicinity of the left side surface of the MFP  100 . In the case where the user is authenticated based on an image output by the camera  140 B, the CPU  111  determines that the position of the authenticated user is in the vicinity of the back surface of the MFP  100 . In the case where the user is authenticated based on an image output by the camera  140 C, the CPU  111  determines that the position of the authenticated user is in the vicinity of the right side surface of the MFP  100 . In the case where the user is authenticated based on an image output by the camera  140 D, the CPU  111  determines that the position of the authenticated user is in the vicinity of the front surface of the MFP  100 . 
         [0069]    The case where the user A is authenticated in the vicinity of the left side surface of the MFP  100 , the user B is authenticated in the vicinity of the back surface of the MFP  100 , and the user C is authenticated in the vicinity of the right side surface of the MFP  100  will be described here as an example. 
         [0070]    Then, the CPU  111  associates the user authenticated in the step S 01  with the position detected in the step S 03  and store them in the HDD  116  (step S 04 ). Specifically, a set of the user identification information for identifying the user and the position identification information for identifying the position is stored in a predetermined region of the HDD  116 . In the next step S 05 , whether a plurality of users are permitted to log in is determined. If the plurality of users are permitted to log in, the process proceeds to the step S 08 . If not, the process proceeds to the step S 06 . 
         [0071]    In the step S 08 , whether an operation has been accepted is determined. The CPU  111  accepts an operation by the user based on the position detected by the touch panel  130 . The operation by the user includes an operation of designating data to be a target of a process, an operation of editing data to be a target of a process, and an operation of deleting data to be a target of a process, for example. If the operation has been accepted, the process proceeds to the step S 09 . If not, the process proceeds to the step S 10 . In the step S 09 , a process is executed in accordance with the operation accepted in the step S 08 , and the process returns to the step S 01 . 
         [0072]    In the step S 10 , whether the user has logged out is determined. The CPU  111  sequentially reads out the sets of the user identification information and the position identification information stored in the step S 04 . Then, if an image of a person as a photographic subject is not included in the image output by the camera corresponding to the position specified by the read position identification information among the cameras  140 A to  140 D, it is determined that the user specified by the read user identification information has logged out. If an image of a person as a photographic subject is included in the image, it is determined that the user is logged in. If any of the users has logged out, the process proceeds to the step S 11 . If not, the process returns to the step S 01 . In the step S 11 , a log-out process for the user who has logged out is executed, and the process returns to the step S 01 . Specifically, the set including the user identification information of the user who has logged out among the sets of the user identification information and the position identification information stored in the step S 04  is erased from the HDD  116 . 
         [0073]    In the step S 12 , whether a job has been received is determined. The CPU  111  determines whether the communication I/F unit  112  has received a job. If the communication I/F unit  112  receives a job, the process proceeds to the step S 13 . If not, the process returns to the step S 01 . The case where a job is received from the PC  200  will be described here as an example. In the step S 13 , whether the activation condition is set for the job received in the step S 12  is determined. If the activation condition is set, the process proceeds to the step S 14 . If not, the process proceeds to the step S 26 . In the step S 26 , the job received in the step S 12  is executed, and the process returns to the step S 01 . 
         [0074]    In the step S 14 , the CPU  111  determines whether a logged-in user is present. Whether a set of the user identification information and the position identification information stored in the HDD  116  in the step S 04  is stored without being erased in the step S 11  is determined. If the set of the user identification information and the position identification information is stored in a predetermined region of the HDD  116 , it is determined that a logged-in user is present. In the case where a logged-in user is present, the process proceeds to the step S 15 . If not, the process proceeds to the step S 27 . In the step S 27 , the job received in the step S 12  is stored in the HDD  116 , and the process returns to the step S 01 . 
         [0075]    In the step S 15 , the CPU  111  notifies the user, of the device that has transmitted the job, of the logged-in user. Specifically, the CPU  111  transmits all of the user identification information stored in the predetermined region of the HDD  116  in the step S 04  to the device, which has transmitted the job received in the step S 12  via the communication I/F unit  112 , that is, the PC  200  in this case. The PC  200 , which receives the user identification information, displays the designated user selection screen that displays the user identification information in a selectable manner. If the user of the PC  200  designates any of the user identification information included in the designated user selection screen, the PC  200  returns the designated user identification information as the information for identifying the designated user. 
         [0076]    In the step S 16 , whether the designated user has been accepted is determined. Whether the communication I/F unit  112  has received the user identification information of the designated user from the PC  200  is determined. The process waits until the communication I/F unit  112  receives the user identification information of the designated user. If the communication I/F unit  112  receives the user identification information of the designated user, the process proceeds to the step S 17 . 
         [0077]    In the next step S 17 , the position of the designated user is specified. The CPU  111  extracts the set including the user identification information that is the same as the user identification information of the designated user among the sets of the user identification information and the position identification information stored in the HDD  116 , and specifies the position identified by the position identification information included in the extracted set. In the case where the user A is designated as the designated user, a position in the vicinity of the left side surface of the MFP  100  is specified. In the case where the user B is designated as the designated user, a position in the vicinity of the back surface of the MFP  100  is specified. In the case where the user C is designated as the designated user, a position in the vicinity of the right side surface of the MFP  100  is specified. 
         [0078]    In the step S 18 , the request screen is displayed in a region corresponding to the position specified in the step  17 . Specifically, the request screen is displayed in the region, corresponding to the position specified in the step S 17 , in the display surface of the display unit  120 . In the case where the user A is designated as the designated user, the request screen is displayed in the first personal display region  121  corresponding to the left side surface of the MFP  100 . In the case where the user B is designated as the designated user, the request screen is displayed in the second personal display region  122  corresponding to the back surface of the MFP  100 . In the case where the user C is designated as the designated user, the request screen is displayed in the third personal display region  123  corresponding to the right side surface of the MFP  100 . In the case where the user is authenticated in the vicinity of the front surface of the MFP  100 , and when the user who is authenticated in the vicinity of the front surface of the MFP  100  is designated as the designated user, the request screen is displayed in the fourth personal display region  124  corresponding to the front surface of the MFP  100 . The request screen is a screen for requesting the designated user to execute the job and acquire a sheet of paper on which an image is formed when the job is executed, and includes the acceding button to which the operation of giving an instruction to accede to the request and the declining button to which the operation of giving an instruction to decline the request is assigned. For example, in the case where the designated user is designated by the user E who operates the PC  200 , the request screen shown in  FIG. 8  is displayed. 
         [0079]    In the step S 19 , whether the acceding operation of acceding to the request has been accepted is determined. If a position within the acceding button has been detected by the touch panel  130 , the CPU  111  accepts the acceding operation. If the acceding operation has been accepted, the process proceeds to the step S 20 . If not, the process proceeds to the step S 24 . In the step S 20 , the notification is made that the designated user has acceded to the request, and the process proceeds to the step S 21 . Specifically, the CPU  111  controls the communication I/F unit  112  and transmits the acceding notification including the message indicating that the designated user has acceded to the request to the PC  200 . Because the PC  200 , which receives the acceding notification, displays the message included in the acceding notification, the user who operates the PC  200  can be informed of the acceding of the request by the designated user. 
         [0080]    In the step S 21 , the activation condition is changed. Specifically, the activation condition included in the job received in the step S 12  is changed to the authentication of the designated user. Because the designated user is authenticated in the step S 01 , the activation condition is satisfied. 
         [0081]    In the next step S 22 , the process waits until the execution instruction by the designated user is accepted. If the execution instruction by the designated user is accepted, the process proceeds to the step S 23 . For example, in the case where an execution instruction button for accepting an execution instruction is displayed in the region, corresponding to the position determined in the step S 17 , in the display surface of the display unit  120 , and the touch panel  130  detects a position within the execution instruction button, the execution instruction is accepted. Because the execution instruction button is displayed in the region, corresponding to the position determined in the step S 17 , in the display surface of the display unit  120 , it is determined that the execution instruction is accepted by the operation of the designated user. In the step S 23 , the job received in the step S 12  is executed, and the process returns to the step S 01 . Specifically, the CPU  111  controls the image forming unit  160  and allows the image forming unit  160  to form an image of the print data included in the job on a sheet of paper in accordance with a print condition included in the job. 
         [0082]    On the other hand, in the step S 24 , the notification is made that the request has been declined, and the process proceeds to the step S 25 . Specifically, the CPU  111  controls the communication I/F unit  112  and returns the declining notification including the message, which indicates that the request has been declined. Because the PC  200 , which receives the declining notification, displays the message included in the declining notification, the user who operates the PC  200  can be informed of declining of the request by the designated user. In the next step S 25 , the job received in the step S 12  is stored in the HDD  116 , and the process returns to the step S 01 . 
         [0083]    The step S 27  or the step S 25  is sometimes performed before the process proceeds to the step S 06 , and the job received in the step S 12  is sometimes stored in the HDD  116 . In the step S 06 , whether a job, having the authentication of the user who has been authenticated in the step S 01  as the activation condition, among the jobs stored in the HDD  116  is stored is determined. If such a job is stored, the CPU  111  reads out the job, and the process proceeds to the step S 07 . If not, the process proceeds to the step S 08 . In the step S 07 , the read job is executed, and the process proceeds to the step S 08 . 
         [0084]      FIG. 11  is a flow chart showing one example of a flow of a job production process. The job production process is a process executed by the CPU  201  in the case where the CPU  201  included in the PC  200  executes the job production program. Referring to  FIG. 11 , the CPU  201  included in the PC  200  produces a job (step S 51 ). The CPU  201  accepts the designation of the data by the user of the PC  200 , a print condition and an activation condition, produces the print data for forming an image in accordance with the print condition, and produces a job including the print data, the print condition and the activation condition. 
         [0085]    In the next step S 52 , the job produced in the step S 51  is transmitted to a device designated by the user via the communication portion  205 , and the process proceeds to the step S 53 . The case where the MFP  100  is designated by the user as a device that executes the job is described here as an example. In this case, the job is transmitted to the MFP  100  via the communication portion  205 . In the step S 53 , whether the communication portion  205  has received the user identification information from the MFP  100  to which the job has been transmitted is determined. If the communication portion  205  has received the user identification information, the process proceeds to the step S 54 . If not, the process ends. 
         [0086]    In the step S 54 , the designated user selection screen is displayed in the display unit  206 , and the process proceeds to the step S 55 . For example, the designated user selection screen shown in  FIG. 7  is displayed. In the step S 55 , whether the selection of the designated user has been accepted is determined. When a user selects any user identification information included in the designated user selection screen, the CPU  201  accepts the selection of the designated user. The process waits until the user selects any user identification information. If the selection of the user identification information is accepted, the process proceeds to the step S 56 . 
         [0087]    In the step S 56 , the selected user identification information is determined as the user identification information of the designated user, and the process proceeds to the step S 57 . In the step S 57 , the MFP  100  is informed of the determined designated user. Specifically, the CPU  201  transmits the user identification information of the designated user who is selected in the step S 55  to the MFP  100  via the communication portion  205 . In the next step S 58 , whether the notification has been received is determined. The process waits until the communication portion  205  receives the acceding notification or the declining notification from the MFP  100 . If the communication portion  205  receives the acceding notification or the declining notification, the process proceeds to the step S 59 . In the step S 59 , the received notification is displayed in the display unit  206 , and the process ends. 
       FIRST MODIFIED EXAMPLE 
       [0088]    While the MFP  100  includes the four cameras  140 A to  140 D provided at the four side surfaces in the above-mentioned embodiment, one camera may be provided at an upper surface of the MFP  100 . The camera in the first modified example is capable of simultaneously picking up images of users who respectively stand in the vicinity of the four side surfaces of the MFP  100  by using a wide-angle lens. The user authentication portion  59  cuts out four images of the positions in the vicinity of the four side surfaces the MFP  100  among the images picked up by the camera, and analyses each of the four cut-out images, thereby authenticating the user. In the case where the user is authenticated, the position of the authenticated user is determined. 
         [0089]    The MFP  100  in the first modified example detects the log-out of the user by analyzing the four images cut out from the image picked up by the camera. It is determined that the user, located at a position corresponding to the image from which an image of a person is no longer detected among the four cut-out images, is logged out. 
       SECOND MODIFIED EXAMPLE 
       [0090]    The MFP  100  in the second modified example authenticates a user by using an ID (Identification) card carried by the user. The MFP  100  in the second modified example is provided with card readers, which read out the authentication information recorded in the ID cards that are carried by the users, at the respective four side surfaces of the MFP  100  instead of the cameras  140 A to  140 D. The authentication information in the second modified example is the user identification information for identifying the user, for example. Further, the authentication information may be card identification information for identifying the cards. In this case, the MFP  100  stores a table that associates the user identification information with the card identification information in the HDD  116 . 
         [0091]    In the case where any of the four card readers respectively provided at the four side surfaces detects an ID card and reads out authentication information, if the authentication information that is the same as the read authentication information is stored in the HDD  116 , the user authentication portion  59  authenticates the user specified by the authentication information. Further, in the case where authenticating the user, the user authentication portion  59  detects a position at which the card reader, which has read out the authentication information of the authenticated user, among the four card readers respectively provided at the four side surfaces is arranged as the position of the user. 
         [0092]    In the case where reading out the authentication information of the user authenticated by the card reader, the MFP  100  in the second modified example detects the log-out of the user. Further, the MFP  100  in the second modified example may display a log-out button in each of the first personal display region  121 , the second personal display region  122 , the third personal display region  123  and the four personal display region  124  in the display surface of the display unit  120 . Then, when the log-out button arranged in any of the first personal display region  121 , the second personal display region  122 , the third personal display region  123 , and the fourth personal display region  124  is designated by the user, the logged-out user may be determined from the position at which the log-out button designated by the user is arranged. In the case where the log-out button arranged in the first personal display region  121  is designated, the log-out of the user who is authenticated in the vicinity of the left side surface of the MFP  100  is detected. In the case where the log-out button arranged in the second personal display region  122  is designated, the log-out of the user who is authenticated in the vicinity of the back surface of the MFP  100  is detected. In the case where the log-out button arranged in the third personal display region  123  is designated, the log-out of the user who is authenticated in the vicinity of the right side surface of the MFP  100  is detected. In the case where the log-out button arranged in the fourth personal display region  124  is designated, the log-out of the user who is authenticated in the vicinity of the front surface of the MFP  100  is detected. 
       THIRD MODIFIED EXAMPLE 
       [0093]    The MFP  100  in the third modified example authenticates the user by using a log-in screen. A user authentication portion  59  in the third modified example displays the log-in screen in each of the first personal display region  121 , the second personal display region  122 , the third personal display region  123 , and the fourth personal display region  124  in the display surface of the display unit  120 . The log-in screen is a screen for accepting authentication information. The authentication information in this case is a set of user identification information for identifying a user and a password. The user authentication portion  59  in the third modified example authenticates the user based on the authentication information that is input in any of the four log-in screens, and determines the position of the authenticated user from a position at which the log-in screen where the authentication information is input is displayed. 
         [0094]    The user authentication portion  59  in the third modified example displays an image of a keyboard including a plurality of keys respectively corresponding to a plurality of characters and numbers in the display unit  120  together with the log-in screen. Then, when the touch panel  130  detects positions in the display surface, the user authentication portion  59  determines an operation of inputting characters or numbers corresponding to the images of the keys displayed at the detected positions, and accepts the user identification information and the password. If the authentication information of the same set as the set of the user identification information and the password accepted in any of the four log-in screens is stored in the HDD  116 , the user authentication portion  59  authenticates the user specified by the user identification information. 
         [0095]    Further, in the case where authenticating the user, the user authentication portion  59  determines a position of the user from the position at which the log-in screen where the authentication information is input is arranged. Specifically, in the case where accepting the authentication information in the log-in screen arranged in the first personal display region  121 , the user authentication portion  59  determines the position of the authenticated user as a position in the vicinity of the left side surface of the MFP  100 . In the case where accepting the authentication information in the log-in screen arranged in the second personal display region  122 , the user authentication portion  59  determines the position of the authenticated user as a position in the vicinity of the back surface of the MFP  100 . In the case where accepting the authentication information in the log-in screen arranged in the third personal display region  123 , the user authentication portion  59  determines a position of the authenticated user as a position in the vicinity of the right side surface of the MFP  100 . In the case where accepting the authentication information in the log-in screen arranged in the four personal display region  124 , the user authentication portion  59  determines the position of the authenticated user as a position in the vicinity of the front surface of the MFP  100 . 
         [0096]    The MFP  100  in the third modified example displays the log-out button in each of the first personal display region  121 , the second personal display region  122 , the third personal display region  123 , and the fourth personal display region  124  in the display surface of the display unit  120 . When the log-out button arranged in any of the first personal display region  121 , the second personal display region  122 , the third personal display region  123 , and the fourth personal display region  124  is designated by the user, a logged-out user is determined from a position at which the log-out button designated by the user is arranged. In the case where the log-out button arranged in the first personal display region  121  is designated, the log-out of the user who is authenticated in the vicinity of the left side surface of the MFP  100  is detected. In the case where the log-out button arranged in the second personal display region  122  is designated, the log-out of the user who is authenticated in the vicinity of the back surface of the MFP  100  is detected. In the case where the log-out button arranged in the third personal display region  123  is designated, the log-out of the user who is authenticated in the vicinity of the right side surface of the MFP  100  is detected. In the case where the log-out button arranged in the fourth personal display region  124  is designated, the log-out of the user who is authenticated in the vicinity of the front surface of the MFP  100  is detected. 
       FOURTH MODIFIED EXAMPLE 
       [0097]    The MFP  100  in the fourth modified example authenticates a user by the short-range communication with a portable information device carried by the user. For example, the short-range communication may be the communication based on NFC (Near Field Communication) standards, or the communication based on the Bluetooth (trademark) standards. 
         [0098]    In this case, in the case where short-range communication devices are respectively arranged at the four side surfaces of the MFP  100 , when any of the four short-range communication devices becomes communicable, the CPU  111  specifies the user by authenticating the user based on the authentication information, which the communicable short-range communication device receives from the portable information device, and specifies a position of the specified user based on the position at which the communicable short-range communication device is arranged. Intra-body communication may be used instead of the short-range communication. 
       FIFTH MODIFIED EXAMPLE 
       [0099]    Further, one short-range communication device may be arranged at the MFP  100 , and proximity sensors may be respectively provided at the four side surfaces of the MFP  100 . In this case, the MFP  100  specifies the user by authenticating the user based on the authentication information, which the short-range communication device receives from a communicable portable information device, and specifies the position of the user from the position at which the proximity sensor that has detected a person among the four proximity sensors is arranged. 
         [0100]    As described above, the MFP  100  in the present embodiment functions as an image forming apparatus and authenticates the user who operates the touch panel  130 . In the case where receiving a job having an activation condition from the PC  200  , the MFP  100  can detect a state of the authenticated user and change the activation condition in response to the detection of a predetermined state of the authenticated user. Therefore, the MFP  100  can change the time when the job is executed. Further, even in the case where a user who operates the MFP  100  is present, the job having the activation condition can be executed early. 
         [0101]    Further, in response to the reception of a job having an activation condition with a plurality of users authenticated, the MFP  100  transmits a plurality of pieces of user identification information for respectively identifying a plurality of users. After transmitting the plurality of pieces of user identification information, in response to reception of a response including the user identification information of the designated user selected by the user who operates the PC  200  among the plurality of users from the PC  200 , the MFP  100  displays the request screen for requesting the execution of the received job. Then, in the case where accepting the response of the designated user after the request screen is displayed, the MFP  100  detects the predetermined state of the designated user. Thus, when accepting the response of the designated user selected by the user who operates the PC  200  among the plurality of users authenticated by the MFP  100 , the MFP  100  detects the predetermined state. Therefore, the user who operates the PC  200  can designate the designated user who acquires a sheet of paper on which an image is formed when the job is executed. Further, the designated user can determine whether to accede to the request by the user who operates the PC  200 . 
         [0102]    Further, in the case where the activation condition is the authentication of the user who operates the PC  200 , the activation condition is changed to the authentication of the designated user, who operates the MFP  100  and is designated by the user who operates the PC  200 . Because the job is executed on the condition that the designated user is authenticated, even when the user who operates the PC  200  is not authenticated by the MFP  100 , the job can be executed. For example, in the case where the job includes highly confidential information, the user who operates the PC  200  may designate a trustworthy user from among the plurality of users who operate the MFP  100  as the designated user. Because the designated user has been already authenticated in the MFP  100 , the job can be executed early. 
         [0103]    Further, the MFP  100  authenticates the user based on the image data output by any of the cameras  140 A to  140 D that picks up an image of a photographic subject. Therefore, the user is authenticated as long as being close to the four side surfaces of the MFP  100 , so that it is not necessary to input an operation for authentication, and the operation can be simplified. 
         [0104]    Further, the MFP  100  displays the log-in screen in the display unit  120  and authenticates the user who operates the MFP  100  based on the authentication information accepted by the touch panel  130 . Therefore, the user is authenticated in the case where inputting the authentication information by using the touch panel  130 . Thus, the user who actually operates the MFP  100  can be authenticated. 
         [0105]    Further, in the case where the designated user, who is authenticated as the user who operates the MFP  100  and designated by the user who operates the PC  200 , accedes to the request, in response to the re-authentication of the designated user, the MFP  100  executes the job having the activation condition. Therefore, after the designated user accedes to the request, the job is executed on the condition that the designated user is authenticated again, so that the designated user can determine the time when the job is executed. 
         [0106]    Further, in the case where receiving a job having the authentication of the user who operates the PC  200  as the activation condition, before the predetermined state is detected for any of the plurality of users who operate the MFP  100 , the MFP  100  executes the job in response to the authentication of the user who operates the PC  200 . However, after the designated user, who is designated by the user who operates the PC  200  among the plurality of users who operate the MFP  100 , accedes to the request, and the predetermined state is detected, the MFP  100  executes the job having the activation condition based on the operation accepted by the touch panel  130 . Thus, the job can be executed by an instruction given by the designated user who actually operates the MFP  100 . Further, because the designated user can give an instruction to execute the job, the designated user can acquire a sheet of paper on which an image is formed when the job is executed, and a user other than the designated user can be prevented from acquiring the sheet of paper on which the image is formed. 
         [0107]    Further, after the designated user, who is designated by the user who operates the PC  200  among the plurality of users who operate the MFP  100 , accedes to the request, and the predetermined state is detected, the MFP  100  executes the job having the activation condition based on the operation accepted in a region in which the log-in screen where the designated user has input the authentication information for authentication is displayed among the first personal display region  121 , the second personal display region  122 , the third personal display region  123 , and the fourth personal display region  124 . Thus, the operation by the designated user can be specified, and the job can be executed by an instruction given by the designated user. Further, because the designated user can give an instruction to execute the job, the designated user can acquire a sheet of paper on which an image is formed when the job is executed, and a user other than the designated user can be prevented from acquiring the sheet of paper on which the image is formed. 
         [0108]    Further, after the designated user, who is designated by the user who operates the PC  200  among the plurality of users who operate the MFP  100 , accedes to the request, and the predetermined state is detected, the MFP  100  executes the job having the activation condition based on an operation accepted in a region corresponding to the position of the designated user among the first personal display region  121 , the second personal display region  122 , the third personal display region  123 , and the fourth personal display region  124 . Thus, an operation by the designated user can be specified, and the job can be executed by an instruction given by the designated user. Further, because the designated user can give an instruction to execute the job, the designated user can acquire a sheet of paper on which an image is formed when the job is executed, and a user other than the designated user can be prevented from acquiring the sheet of paper on which the image is formed. 
         [0109]    Further, after the designated user, who is designated by the user who operates the PC  200  among the plurality of users who operate the MFP  100 , accedes to the request, and the predetermined state is detected, the MFP  100  in the third modified example executes the job having the activation condition based on the operation accepted in a region in which the log-in screen where the designated user has input the authentication information for authentication among the first personal display region  121 , the second personal display region  122 , the third personal display region  123 , and the fourth personal display region  124 . Thus, MFP  100  can specify the operation by the designated user and execute the job by an instruction given by the designated user. Further, because the designated user can give an instruction to execute the job, the designated user can acquire a sheet of paper on which an image is formed when the job is executed, and a user other than the designated user can be prevented from acquiring the sheet of paper on which the image is formed. 
         [0110]    While the MFP  100  is described as one example of the image forming apparatus in the present embodiment, it is needless to say that the invention can be regarded as a print control method for allowing the MFP  100  to execute a print control process shown in  FIGS. 9 and 10  or a print control program that allows the CPU  111  included in the MFP  100  to perform the print control method. 
         [0111]    Although the present invention has been described and illustrated in detail, it is clearly understood that the same is by way of illustrated and example only and is not to be taken by way of limitation, the scope of the present invention being interpreted by terms of the appended claims