Patent Publication Number: US-9854122-B2

Title: Image forming apparatus, data management method, and storage medium

Description:
CROSS REFERENCE TO RELATION APPLICATION 
     This application is a Continuation of U.S. application Ser. No. 14/644,014, filed Mar. 10, 2015, which claims priority from Japanese Patent Application No. 2014-052082, filed Mar. 14, 2014, which are hereby incorporated by reference herein in their entireties. 
    
    
     BACKGROUND 
     Field 
     Aspects of the present invention generally relate to an image forming apparatus, a data management method, and a program. 
     Description of the Related Art 
     Recent image forming apparatuses have various functions, and contents of operations performed by a user have been complicated. Generally, the image forming apparatus is often shared by a plurality of users, and an auto-clear function is utilized therein which automatically clears a setting value after elapse of a certain period of time from the setting value has been changed so that a next user does not use the image forming apparatus without noticing the changed setting. In such a utilization form, a user needs to select every time a desired setting screen from an initial menu of the image forming apparatus. Thus, even if users have their individual setting values usually use, they each have to perform the same setting every time and it is bothersome. For example, assume that initial values in job settings of a copy function are “1 in 1” in a layout setting and “no finishing” in a finishing setting. A certain user changes the layout setting to “2 in 1” and the finishing setting to “staple on upper right” to use the copy function. 
     For another example, in a case of the image forming apparatus of which display language is set to Japanese, a user A who wants to use the apparatus in English as the display language sets a display language setting to English in a user setting. Accordingly, when the user A logs in to the image forming apparatus, the image forming apparatus displays each function in English. As described above, the image forming apparatus can save the settings of each user and provide an environment convenient for each user to use. 
     When many users use such an image forming apparatus, many personal settings are registered in a single image forming apparatus. However, a storage capacity resource of the image forming apparatus is limited, and it is necessary to delete a user setting value which is no longer used. In order to save a time and effort of an administrator, unnecessary setting values are required to be automatically deleted. As a technique for deleting unnecessary data, Japanese Patent Application Laid-Open No. 10-143910 discusses a technique for deleting removable data when a sufficient storage capacity cannot be secured when data is stored. 
     However, if data deletion processing is executed to add new setting information during execution of a copy job or the like in the image forming apparatus, performance of job execution is affected by the processing. Further, it is troublesome for an administrator to manually execute the data deletion processing to secure a necessary capacity size. 
     SUMMARY 
     Aspects of the present invention are generally directed to a technique for executing data deletion processing to secure a storage capacity for registering setting information without deteriorating performance of other job execution. 
     According to an aspect of the present invention, an image forming apparatus includes a state management unit configured to shift an authentication state from a non-login state to a login state, a storage unit configured to store setting information, and a data management unit configured to, in a case where a free space of the storage unit is less than a threshold value, delete the setting information stored in the storage unit at a timing of shifting from the non-login state to the login state and secure a free space greater than or equal to the threshold value in the storage unit. 
     According to aspects of the present invention, data deletion processing can be executed to secure a storage capacity for registering setting information without deteriorating performance of other job execution. 
     Further features of the present disclosure will become apparent from the following description of exemplary embodiments with reference to the attached drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates an example of a hardware configuration of a multifunction peripheral (MFP). 
         FIG. 2  illustrates an example of a software configuration of an MFP. 
         FIG. 3  illustrates an example of a data configuration of a setting database (DB). 
         FIG. 4  illustrates how display language is set. 
         FIGS. 5A to 5D  are tables of a data configuration of a management table DB. 
         FIG. 6A  is a flowchart illustrating login processing. 
         FIG. 6B  is a flowchart illustrating login processing. 
         FIG. 7  illustrates an example of a login screen. 
         FIG. 8  is a flowchart illustrating logout processing. 
         FIG. 9  illustrates an image forming system. 
         FIG. 10  illustrates an example of a software configuration of an MFP according to a second exemplary embodiment. 
         FIG. 11  is a sequence diagram illustrating master setting DB update processing. 
         FIG. 12  is a flowchart illustrating setting DB update processing. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     Various exemplary embodiments will be described in detail below with reference to the drawings. 
       FIG. 1  illustrates an example of a hardware configuration of a multifunction peripheral (MFP). An MFP  101  is an example of an image forming apparatus. A central processing unit (CPU)  111 , a random access memory (RAM)  112 , a read-only memory (ROM)  113 , an input control interface (I/F)  114 , a display control I/F  115 , a storage device I/F  116 , and a communication I/F controller  117  are connected to a system bus  110 . Further, a scanner  121  and a printer  122  are also connected to the system bus  110 . Each unit connected to the system bus  110  can exchange data with each other via the system bus  110 . 
     The CPU  111  is a device which controls each device and performs calculation and processing of data. The RAM  112  is a volatile memory and used as a temporary storage area, such as a main memory and a work area, of the CPU  111 . The ROM  113  is a non-volatile memory and stores image data, other data pieces, various programs for the CPU  111  to operate, and so on in predetermined areas thereof. For example, the CPU  111  controls each unit in the MFP  101  using the RAM  112  as a work memory according to a program stored in the ROM  113 . In this regard, the program for the CPU  111  to operate is not limited to the one stored in the ROM and may be stored in a storage device  120 . When the CPU  111  executes processing based on the program, a software configuration of the MFP  101  and processing in flowcharts, which are described below, are realized. 
     The input control I/F  114  receives a user operation, generates a control signal in response to the operation, and supplies the control signal to the CPU  111 . For example, the input control I/F  114  is served as an input device for receiving a user operation and connected to a character information input device, such as a keyboard not illustrated, a hard key for a user to directly input numerical values or the like, a pointing device, such as a touch panel  118 , and so on. The touch panel  118  is, for example, an input device which includes an input portion having a planar form and outputs coordinate information corresponding to a touched position on the input portion. According to a first exemplary embodiment, an operation on the touch panel is described below as a user operation. However, a user operation is not limited to an operation on the touch panel. The CPU  111  controls each unit in the MFP  101  according to a program based on a control signal which is generated and supplied from the input control I/F  114  in response to a user operation performed on the input device. Accordingly, the CPU  111  can cause the MFP  101  to operate in response to the user operation. 
     The display control I/F  115  outputs a display signal to a display  119  to display an image. For example, the CPU  111  supplies the display control I/F  115  with a generated display control signal according to a program. The display control I/F  115  generates a display signal based on the display control signal and outputs the display signal to the display  119 . For example, the display control I/F  115  causes the display  119  to display a graphical user interface (GUI) screen forming a GUI based on the display control signal generated by the CPU  111 . The touch panel  118  may be integrated into the display  119 . For example, the touch panel  118  is formed to have a light transmittance which does not hinder display of the display  119  and mounted on an upper layer of a display surface of the display  119 . Input coordinates on the touch panel  118  are associated with display coordinates on the display  119 . Accordingly, a GUI can be formed which allows a user to feel like directly operating a screen displayed on the display  119 . 
     The storage device I/F  116  can mount the storage device  120 , for example, a hard disk drive (HDD), a flash memory, and a memory card, therein. The storage device I/F  116  read and write data from and to the mounted storage device  120  based on the control by the CPU  111 . Depending on the configuration, the CPU  111  can use the storage device  120  in place of the ROM  113 . The communication I/F controller  117  performs communication with various wired and wireless networks, such as a local area network (LAN) and the Internet, based on the control by the CPU  111 . To a network  102 , various apparatuses including a personal computer (PC), other MFPs, a printer, a server, and the like are connected so as to communicate with the MFP  101 . 
     The scanner  121  reads a document and generates image data based on the control by the CPU  111 . For example, the CPU  111  causes the scanner  121  to perform scan processing in response to an instruction input by a user via the input control I/F  114 . The scanner  121  reads a document placed on a platen or an automatic document feeder (ADF) and converts the read document into digital data to generate image data. The scanner  121  further stores the generated image data into the storage device  120  via the storage device I/F  116 . The printer  122  performs print processing of image data stored in the storage device  120  based on the control by the CPU  111 . For example, the CPU  111  causes the printer  122  to perform print processing in response to a user&#39;s instruction input via the input control I/F  114  and a command instruction input from an external apparatus via the communication I/F controller  117 . The printer  122  reads image data from the storage device  120 , converts the image data into a printable data format, and print the data to a paper document. 
     The software configuration of the MFP  101  is described with reference to  FIG. 2 . The software configuration of the MFP  101  illustrated in  FIG. 2  is an example for the description of the present exemplary embodiment. Thus, the software configuration of the MFP  101  may include other components in addition to the configuration illustrated in  FIG. 2  or have a different configuration which can provide effects similar to those of the present exemplary embodiment. A program corresponding to each control unit in  FIG. 2  is stored in the ROM  113 , developed in the RAM  112  as necessary at startup or when a function is used, and executed by the CPU  111 . Accordingly, each control unit illustrated in  FIG. 2  can be realized. 
     The MFP  101  includes the control units, for example, a display operation control unit  201 , an authentication control unit  202 , and a setting value control unit  203 . The MFP  101  includes one or more functions. The control unit is provided for each of the functions. In  FIG. 2 , a copy control unit  210 , a scan control unit  211 , and a transmission control unit  212  are illustrated as an example. Needless to say, the MFP  101  may include functions and control units corresponding to the functions related to processing in the MFP  101  other than the functions shown in  FIG. 2 . 
     The display operation control unit  201  controls the input control I/F  114  and the display control I/F  115 . For example, the display operation control unit  201  causes the display  119  to display via the display control I/F  115  based on an instruction from the other control unit and obtains information input by a user to the touch panel  118  via the input control I/F  114 . The display operation control unit  201  notifies each of the control units of the obtained information. 
     An authentication information DB  320  is recorded in the storage device  120 . The authentication information DB  320  regards an individual person as a registrant, namely a legitimate user of the MFP  101 , and stores authentication information of the registrant. The authentication information includes a user name indicating the registrant, a password, and a personal identifier. More specifically, the authentication information DB  320  stores the user name, the password, and the personal identifier by associating them with each other. In addition, each individual person can belong to a group. A group includes a plurality of persons as members. A single person can belong to a plurality of groups. The authentication information DB  320  further stores information indicating a personal user belonging to each group. 
     The authentication control unit  202  executes authentication processing to determine whether an operator of the MFP  101  is a legitimate user of the MFP  101 . More specifically, the operator inputs a personal name and a password. If the input user name and password match a combination of a user name and a password stored in the authentication information DB  320 , the authentication control unit  202  determines that the operator is the legitimate user. The authentication control unit  202  starts a session if the operator is the legitimate user. Further, the authentication control unit  202  terminates the session when the operator end the use of the MFP  101 . In the following description, an operation that the authentication control unit  202  determines the operator as the legitimate user and starts a session is referred to as login, and an operation that the authentication control unit  202  terminates the session is referred to as logout. Login processing and logout processing are described below. The authentication control unit  202  also controls the authentication information DB  320 . 
     The authentication control unit  202  provides functions of registering and deleting an individual person and updating personal authentication information. The authentication control unit  202  further provides functions of making a certain person to belong a group and withdrawing a certain person from a group. 
     As another example, the authentication control unit  202  may connect to an external authentication server (not illustrated) via the communication I/F controller  117  and use an authentication result of the authentication server. A conventional technique can be used for exchanging the authentication information with the external authentication server. 
     A setting DB  400  is recorded in the storage device  120 . The setting DB  400  stores shared setting information, personal setting information, and group setting information. The shared setting information is information that an operator can refer to and use in a non-login state. The personal setting information is information that only a personal user as the registrant can refer to and use. The group setting information is information that only a group member belonging to the group can refer to and use. Each of the setting information pieces (the shared setting information, the personal setting information, and the group setting information) includes a setting item and a setting value set to the setting item. In the following description, the shared setting information, the personal setting information, and the group setting information are collectively referred to as setting information accordingly. The setting value control unit  203  registers, changes, and deletes the shared setting information, the personal setting information, and the group setting information in the setting DB  400  in response to a user operation performed on the touch panel  118  based on instruction information obtained from the display operation control unit  201 . 
     A management table DB  500  is recorded in the storage device  120 . The management table DB  500  stores information, such as the number of the setting information pieces and a data size which are set to the setting DB  400 . The setting value control unit  203  updates the management table DB  500  according to update of the setting DB  400 . The setting value control unit  203  further refers to the management table DB  500  and appropriately executes automatic deletion of data (the setting information) registered in the setting DB  400 . The automatic deletion is described below. 
       FIG. 3  illustrates an example of a data configuration of the setting DB  400 . The setting DB  400  stores setting information therein. The setting information includes a key for specifying a setting item and a setting value as a combination. The setting DB  400  is expressed in a hierarchical structure. A first hierarchy includes information of a target  401 . The target  401  is a usage target of the setting information and identification information for specifying shared use, an individual person, and a group, and identifying each individual person and each group. For the target  401  as an individual person, a personal identifier is used which indicates that the target is an individual person and identifies each individual person. For the target  401  as a group, a group identifier is used which indicates that the target is a group and identifies each group. In the example illustrated in  FIG. 3 , it is set that “shared use” as information specifying a shared use, “user A” and “user B” as personal identifiers of respective personal users A and B, and “Group 1” as a group identifier of a group user 1. A corresponding setting value  403  is determined by a combination of the target  401  and a key (setting item)  402 . 
     In the example illustrated in  FIG. 3 , when the target is the “user A”, a setting value corresponding to a key “display language” is “Japanese”. When the target is the “user B”, a setting value corresponding to a key “display language” is “Chinese”. In addition, when the target is the “user B”, a setting value corresponding to a key “personal address book—a personal address 1” is “ccc@abc.com”. The personal setting information is stored as many as the number of the personal users, whereas the shared setting information is an only setting value in the MFP  101 . In the example in  FIG. 3 , a setting value corresponding to a key “shared use—display language” is “English”. When the target is the “Group 1”, a setting value corresponding to a key “group address book—group address 1” is “g1@abc.com”. 
     In addition, assume that the personal user A and the personal user B belong to the group user 1, for example. In this case, the personal user A and the personal user B can refer to the group address 1, however a personal user C who does not belong the group user 1 cannot refer to the group address 1. 
     The setting DB  400  includes some setting information pieces which have the same keys in the personal setting information and the shared setting information and other setting information pieces which do not. When the setting information pieces have the same ley, a setting value (shared setting value) of the shared setting information may sometimes be used as an initial value of a setting value (personal setting value) of the personal setting information if it is not registered. In the example in  FIG. 3 , personal setting information of a user C is not registered. In this case, “English” which is the shared setting value is applied to the display language of the user C. In the case that the personal setting information and the shared setting information do not have the same key, it is regarded that the personal setting information is not registered or the number of registration is null. For example, a key “personal address book” is a key existing only in the setting information of the target “individual person” (an address book is described below). To the contrary, a “shared address book” is a key existing only for the target “shared use”. In the example in  FIG. 3 , a personal address book of the personal user C is null, but there is the shared setting information. Thus the personal user C can refer to a shared address 1, a shared address 2, and a shared address 3 in the shared address book. 
     The setting value control unit  203  reads a personal setting value in the setting DB  400  at the time of login and reflects the read value to each setting information of the MFP  101 . Thus, an operator can uses the MFP  101  of which settings are customized according to the personal setting information that the operator registered by himself or herself. Further, the setting value control unit  203  reads the setting value (shared setting value) of the shared setting information in the setting DB  400  at the time of logout and reflects the read value to each setting information of the MFP  101 . Thus, a function which can be used in the non-login state can be used in the shared setting value. 
     As an example of the personal setting, the display language setting is described with reference to  FIG. 4 . The setting information pieces shown in  FIG. 3  are stored in the setting DB  400 .  FIG. 4  illustrates a state when a user A logs in to the MFP  101 , and a screen shifts from a login screen  411  to a main menu screen  412  after the login. As illustrated in  FIG. 3 , regarding the display language setting of the shared setting, the key “display language” of the target “shared use” has the setting value “English”. Whereas, regarding the display language setting of the user A, the key “display language” of the target “user A” has the setting value “Japanese”. 
     The login screen  411  is a screen displayed in the non-login state. Thus, on the login screen  411 , the shared setting information is used, and characters on the login screen  411  are displayed in “English” according to the setting value of the display language. 
     The main menu screen  412  is a screen displayed after the login processing is successful and a state is shifted from the non-login state to the login state. Thus, on the main menu screen  412 , the personal setting information of the user A is used, and characters on the main menu screen  412  are displayed in “Japanese” according to the setting value of the display language. 
     The setting items in  FIG. 3  are examples. The setting items may include a keyboard setting, an accessibility setting, and functions to be displayed after the login in addition to the above-described setting items, and these setting items can be customized as the personal setting. The personal setting information may further include personal data of each function, such as an address book of each individual person. Needless to say, the personal setting information may include settings of each personal user of the MFP  101  other than those described above. 
       FIGS. 5A to 5D  are tables in a data configuration of the management table DB  500 . The management table DB  500  includes an upper limit table  501 , a personal management table  502 , a group management table  503 , and a deletion management table  504 . As shown in  FIG. 5A , the upper limit table  501  stores a maximum number of personal users, a maximum number of group users, a maximum data size of a single personal user, a maximum data size of a single group user, and an entire storage capacity therein. The maximum number of personal users and the maximum number of group users are respectively the number of the personal setting information pieces and the number of the group setting information pieces which can be registered in the setting DB  400 . Further, the maximum data size of a single personal user and the maximum data size of a single group user are respectively maximum sizes of data which can be recorded as the setting information of a single personal user and a single group user. The entire storage capacity is a size of an entire storage capacity for storing the setting information. Each value in the upper limit table  501  is determined in advance. 
     In the upper limit table  501  shown in  FIG. 5A , the maximum number of personal users is set to 5, the maximum number of group users is set to 3, the maximum data size of a single personal user is set to 1 MB, the maximum data size of a single group user is set to 2 MB, and the entire storage capacity is set to 10 MB. 
     As shown in  FIG. 5B , the personal management table  502  stores the number of registered personal users. The number of registered personal users is the number of the personal users whose setting information pieces are registered in the setting DB  400 . The personal management table  502  further stores a personal identifier of the registered personal user, the storage capacity size actually being used, and a time and date of last use of the setting value in the personal setting information corresponding to the personal user in association with each other. Each information in the personal management table  502  is managed by the setting value control unit  203 . In other words, the setting value control unit  203  performs registration, update, and deletion of each information in the personal management table  502 . 
     In the personal management table  502  shown in  FIG. 5B , the number of registered personal users is set to 5, a used capacity of the user A is set to 50 KB, and the time and date of last use is set to Nov. 7, 2013. In the personal management table  502 , the used capacity and the time and date of last use are similarly set to each of the users B, C, D, and E. 
     As shown in  FIG. 5C , the group management table  503  stores the number of registered group users. The number of registered group users is the number of group users, namely the number of groups of which setting information pieces are registered in the setting DB  400 . The group management table  503  further stores a group identifier of the registered group user, the storage capacity size actually being used, and a time and date of last use of the setting value in the group setting information corresponding to the group user in association with each other. Each information in the group management table  503  is managed by the setting value control unit  203 . In other words, the setting value control unit  203  performs registration, update, and deletion of each information in the group management table  503 . 
     In the group management table  503  shown in  FIG. 5C , the number of registered group users is set to 2, a used capacity of the group 1 is set to 470 KB, and the time and date of last use is set to Nov. 7, 2013. 
     As shown in  FIG. 5D , the deletion management table  504  stores a used storage capacity, automatic deletion of person, and automatic deletion of group therein. The used storage capacity is a total size of the storage capacities which are being used by each personal user and each group user to store the setting information pieces. The automatic deletion of person is information indicating ON and OFF of an automatic deletion function of the personal setting information. The automatic deletion of group is information indicating ON and OFF of an automatic deletion function of the group setting information. In the deletion management table  504  shown in  FIG. 5D , the used storage capacity is set to 8 MB, and both of the automatic deletion of person and the automatic deletion of group are set to ON. 
     The automatic deletion is described below. There are upper limits of the number of personal users and the number of group users of which setting information pieces can be managed in the MFP  101 . More specifically, in the upper limit table  501  in  FIG. 5A , the maximum number of personal users and the maximum number of group users are set as the upper limits of the number of personal users and the number of group users. Thus, when personal users and group users exceeding the upper limits try to register setting information, processing causes an error, and a new user cannot register setting information. 
     In this regard, the MFP  101  according to the present exemplary embodiment has the automatic deletion function of automatically deleting the setting information stored in the setting DB  400 . The automatic deletion function is a function that the setting value control unit  203  automatically deletes the setting information stored in the setting DB  400 . The setting value control unit  203  deletes the setting information not in units of setting values but in unit of users, namely units of setting information. This is because, a plurality of setting values corresponding to individual functions may be operated in conjunction with each other, and in such a case, if the setting information is deleted in units of setting values, it may cause an incomplete state, such as a setting value of an associated destination does not exist. 
     Further, the setting value control unit  203  automatically deletes the setting information of which time and date of last use is old at a timing when the non-login state is shifted to the login state. Accordingly, when a new user logs in, the MFP  101  can secure a free space having a size sufficient to register setting information of the new user therein without troubling an administrator in a situation in which the number of the registered setting information pieces has reached the upper limit. 
     The setting value control unit  203  not only deletes the oldest personal setting information or the oldest group setting information, but also repeats the processing for deleting the oldest personal setting information or the like until a free space for a new registration size is secured in the setting DB  400 . The new registration size is a free space in the setting DB  400  as a storage unit which is necessary for registration of setting information of a new user (operator) whose setting information is not registered in the setting DB  400 . According to the present exemplary embodiment, the maximum data size of a single personal user or a single group user is regarded as the new registration size. In addition, the setting value control unit  203  executes the automatic deletion function only when the automatic deletion is set to ON in the deletion management table  504  shown in  FIG. 5D . 
     A case when each information shown in  FIGS. 5A to 5D  is stored in the management table DB  500  is described in detail below as an example. In the upper limit table  501  shown in  FIG. 5A , the maximum number of personal users is set to 5, and in the personal management table  502  shown in  FIG. 5B , the number of registered personal users is set to 5. Thus, the number of personal users who can register the personal setting information has already reached the upper limit. Further, in the deletion management table  504  shown in  FIG. 5D , the automatic deletion of person is set to ON. 
     Therefore, if a new user logs in to the MFP  101  in this state, the setting value control unit  203  refers to the personal management table  502  in  FIG. 5B  to specify the personal user whose time and date of last use is the oldest. Then, the setting value control unit  203  deletes a record (the personal identifier, the used capacity, and the time and date of last use) of the specified personal user from the personal management table  502  and further deletes the personal setting information of the specified personal user from the setting DB  400 . 
     More specifically, the setting value control unit  203  first deletes a record and the personal setting information corresponding to the user C whose time and date of last use is the oldest. The used capacity of the user C in the setting DB  400  is 130 KB, which is less than 1 MB. Thus, the setting value control unit  203  further deletes a record and the personal setting information corresponding to the user B whose time and date of last use is the next oldest to the user C. Accordingly, a deleted data size becomes 130 KB+1 MB (1024 KB)=1154 KB, which is greater than the maximum data size of a single personal user 1 MB (1024 KB). 
     As described above, when a new user logs in to the MFP  101 , the setting value control unit  203  deletes the setting information pieces of a plurality of users until a free space corresponding to the maximum data size of a single personal user can be secured. Deletion of a plurality of personal users is described above, and the same applies to the group users. 
     During the login, high load processing (a job), like copy processing, is often executed. However, the MFP  101  according to the present exemplary embodiment has already completed the deletion processing of the setting information when shifting to the login state, so that the deletion of the setting information is not executed during the login. Therefore, performance of operations during the login can be prevented from deteriorating. 
     The MFP  101  also executes the automatic deletion when running out of a capacity for storing the setting information in the setting DB  400 . More specifically, the MFP  101  regards a value obtained by subtracting the maximum data size of a single personal user or the maximum data size of a single group user from the entire storage capacity in  FIG. 5A  as a used capacity threshold value. Then, the MFP  101  executes the automatic deletion when the used storage capacity in the deletion management table  504  in  FIG. 5D  is equal to or greater than the used capacity threshold value. In other words, the MFP  101  executes the automatic deletion when the free space in the setting DB  400  is less than a free space threshold value. 
     In the example in  FIGS. 5A to 5D , the entire storage capacity is 10 MB, and the maximum data size of a single personal user and the maximum data size of a single group user are respectively 1 MB and 2 MB. Therefore, the used capacity threshold value is 7 MB (=10 MB−1 MB−2 MB). The used capacity threshold value is not limited to the one described in the present exemplary embodiment. The automatic deletion in response to a comparison result with the capacity threshold value is also executed only on a target of which automatic deletion of person and automatic deletion of group are ON in the deletion management table  504 . 
       FIGS. 6A and 6B  are flowcharts illustrating login processing. The authentication control unit  202  starts the login processing when an operator instructs login. As described above, processing by the authentication control unit  202  is executed when a program stored in the ROM  113  is controlled by the CPU  111 . The authentication control unit  202  transmits a request to each control unit to execute processing in the following flowcharts. A case when the MFP  101  executes authentication is described below, however the authentication may be executed by an external server. 
     In step S 4000 , the display operation control unit  201  displays a login screen  700  on the display  119 .  FIG. 7  illustrates an example of the login screen  700 . The login screen  700  includes a user name input form  701 , a password input form  702 , a login destination selection button  703 , and a login button  704 . An operator inputs a user name to the user name input form  701  and a password corresponding to the password input form  702 . The login destination selection button  703  is used to select an authentication destination. When the authentication is executed based on the authentication information DB  320  in the MFP  101 , “This device” is selected as illustrated in  FIG. 7 . When the external authentication server executes authentication, an operator selects a name of the external authentication server in the login destination selection button  703 , and the selected authentication server executes the authentication. 
     Returning to  FIG. 6A , in step S 4001 , when an operator executes input processing using the touch panel  118 , the display operation control unit  201  receives a user name from the user name input form  701  and a password from the password input form  702  via the display control I/F  115 . The authentication control unit  202  receives the user name and the password input in step S 4001  from the display operation control unit  201 , and in step S 4002 , collates whether the received user name and password match with the user name and the password in the authentication information DB  320 . 
     In the case that the external authentication server executes the authentication, in step S 4002 , the authentication control unit  202  performs encryption or obfuscation on the input user name and password via the communication I/F controller  117 . Then, the authentication control unit  202  requests the external authentication server to authenticate the encrypted or obfuscated information and receives an authentication result therefrom. 
     In step S 4002 , if collated information does not match with each other (NO in step S 4002 ), the authentication control unit  202  advances the processing to step S 4003 . In step S 4003 , the authentication control unit  202  determines that the login failed, notifies the operator of login failure via the display operation control unit  201 , and then advances the processing to login reception processing in step S 4000 . 
     In step S 4002 , if collated information matches with each other (YES in step S 4002 ), the authentication control unit  202  determines that the authentication is successful, in other words, the operator is a legitimate user, and advances the processing to step S 4004 . In step S 4004 , the authentication control unit  202  changes an authentication state from the non-login state to the login state and issues a personal identifier for uniquely specifying the operator. The processing in step S 4004  is an example of state management processing for shifting the authentication information from the non-login state to the login state when the operator is the legitimate user. Next, in step S 4005 , the authentication control unit  202  issues a group identifier of a group to which the personal identifier issued in step S 4004  belongs. 
     In step S 4006 , the setting value control unit  203  determines whether the operator is a new personal user. More specifically, if the personal identifier issued in step S 4004  is not stored in the personal management table  502  of the management table DB  500  (see  FIG. 5B ), the setting value control unit  203  determines that the operator is a new personal user. If it is determined that the operator is a new personal user (YES in step S 4006 ), the setting value control unit  203  advances the processing to step S 4007 . If it is determined that the operator is not a new personal user (NO in step S 4006 ), the setting value control unit  203  advances the processing to step S 4014 . The processing in step S 4006  is an example of registration confirmation processing for determining whether the personal setting information of the operator is registered in the setting DB  400  as the storage unit. 
     In step S 4007 , the setting value control unit  203  determines whether the number of registered personal users in the personal management table  502  of the management table DB  500  has reached the upper limit (a personal threshold value). The upper limit is the maximum number of personal users in the upper limit table  501  of the management table DB  500  (see  FIG. 5A ). In other words, when the number of registered personal users in the personal management table  502  matches with the maximum number of personal users in the upper limit table  501 , namely is the personal threshold value or greater, the setting value control unit  203  determines that the number of registered personal users has reached the upper limit. If it is determined that the number of registered personal users has reached the upper limit (YES in step S 4007 ), the setting value control unit  203  advances the processing to step S 4008 . If it is determined that the number of registered personal users has not reached the upper limit (NO in step S 4007 ), the setting value control unit  203  advances the processing to step S 4014 . 
     In step S 4008 , the setting value control unit  203  determines whether the automatic deletion of person is ON in the deletion management table  504  of the management table DB  500  (see  FIG. 5D ). If the automatic deletion of person is ON (YES in step S 4008 ), the setting value control unit  203  advances the processing to step S 4010 . If the automatic deletion of person is OFF (NO in step S 4008 ), the setting value control unit  203  advances the processing to step S 4009 . In step S 4009 , the setting value control unit  203  prohibits registration of the personal setting information regarding the personal identifier obtained in step S 4004 . More specifically, the setting value control unit  203  sets “non-storable” in a personal setting storage flag (not illustrated) indicating prohibition of storage of the personal setting information and advances the processing to step S 4014 . The personal setting storage flag is set to “storable” as a default value. In the case that an application or the like stores the personal setting information, and “non-storable” is set to the personal setting storage flag, the setting value control unit  203  returns an error. 
     In step S 4010 , the setting value control unit  203  obtains the maximum data size that a single personal user can store from the upper limit table  501  (see  FIG. 5A ). Next, in step S 4011 , the setting value control unit  203  specifies the personal identifier of which time and date of last use is the oldest in the personal management table  502  and selects the personal user corresponding to the personal identifier. Next, in step S 4012 , the setting value control unit  203  deletes a record corresponding to the personal identifier selected in step S 4011  from the personal management table  502  and deletes the personal setting information corresponding to the selected personal identifier from the setting DB  400 . Further, the setting value control unit  203  updates the used storage capacity in the deletion management table  504  of the management table DB  500  according to a data size of the deleted personal setting information. 
     Next, in step S 4013 , the setting value control unit  203  determines whether a new registration size of the personal user is secured. The new registration size is the maximum data size of a single personal user. More specifically, the setting value control unit  203  compares the maximum data size of a single personal user in the upper limit table  501  with a value (free space) obtained by subtracting the used storage capacity in the deletion management table  504  (see  FIG. 5D ) from the entire storage capacity in the upper limit table  501  (see  FIG. 5A ). If a free space is equal to or greater than the maximum data size of a single personal user, the setting value control unit  203  determines that the new registration size is secured. 
     If the new registration size is secured (YES in step S 4013 ), the setting value control unit  203  advances the processing to step S 4014 . If the new registration size is not secured (NO in step S 4013 ), the setting value control unit  203  advances the processing to step S 4010  to repeat the deletion processing. The processing in steps S 4010  to S 4013  is an example of data management processing for deleting one or more personal setting information pieces registered in the setting DB  400  as the storage unit and securing a new registration size necessary for registration of the personal setting information of the operator. 
     In step S 4014 , the setting value control unit  203  determines whether the operator is a new group user. More specifically, if the group identifier issued in step S 4005  is not stored in the group management table  503  of the management table DB  500  (see  FIG. 5C ), the setting value control unit  203  determines that the operator is a new group user. If it is determined that the operator is a new group user (YES in step S 4014 ), the setting value control unit  203  advances the processing to step S 4015 . 
     If it is determined that the operator is not a new group user (NO in step S 4014 ), the setting value control unit  203  advances the processing to step S 4022 . The processing in step S 4014  is an example of registration confirmation processing for determining whether the group setting information of the operator is registered in the setting DB  400  as the storage unit. 
     In step S 4015 , the setting value control unit  203  determines whether the number of registered group users in the group management table  503  of the management table DB  500  has reached the upper limit (a group threshold value). The upper limit is the maximum number of group users in the upper limit table  501  of the management table DB  500  (see  FIG. 5A ). In other words, when the number of registered group users in the group management table  503  matches with the maximum number of group users in the upper limit table  501 , namely is the group threshold value or greater, the setting value control unit  203  determines that the number of registered group users has reached the upper limit. 
     If it is determined that the number of registered group users has reached the upper limit (YES in step S 4015 ), the setting value control unit  203  advances the processing to step S 4016 . If it is determined that the number of registered group users has not reached the upper limit (NO in step S 4015 ), the setting value control unit  203  advances the processing to step S 4022 . 
     In step S 4016 , the setting value control unit  203  determines whether the automatic deletion of group is ON in the deletion management table  504  of the management table DB  500  (see  FIG. 5D ). If the automatic deletion of group is ON (YES in step S 4016 ), the setting value control unit  203  advances the processing to step S 4018 . If the automatic deletion of group is OFF (NO in step S 4016 ), the setting value control unit  203  advances the processing to step S 4017 . In step S 4017 , the setting value control unit  203  prohibits registration of the group setting information regarding the group identifier obtained in step S 4005 . More specifically, the setting value control unit  203  sets “non-storable” in a group setting storage flag (not illustrated) indicating prohibition of storage of the group setting information and advances the processing to step S 4022 . The group setting storage flag is set to “storable” as a default value. In the case that an application or the like stores the group setting information, and “non-storable” is set to the group setting storage flag, the setting value control unit  203  returns an error. 
     In step S 4018 , the setting value control unit  203  obtains the maximum data size that a single group can store from the upper limit table  501  (see  FIG. 5A ). Next, in step S 4019 , the setting value control unit  203  specifies the oldest time and date of last use in the group management table  503  and selects the group user corresponding to the specified data. Next, in step S 4020 , the setting value control unit  203  deletes a record corresponding to the group identifier selected in step S 4019  from the group management table  503  and deletes the group setting information corresponding to the selected group identifier from the setting DB  400 . Further, the setting value control unit  203  updates the used storage capacity in the deletion management table  504  of the management table DB  500  according to a data size of the deleted group setting information. 
     Next, in step S 4021 , the setting value control unit  203  determines whether a new registration size of the group user is secured. The new registration size is the maximum data size of a single group user. More specifically, the setting value control unit  203  compares the maximum data size of a single group user in the upper limit table  501  with a value (free space) obtained by subtracting the used storage capacity in the deletion management table  504  (see  FIG. 5D ) from the entire storage capacity in the upper limit table  501  (see  FIG. 5A ). If a free space is equal to or greater than the maximum data size of a single group user, the setting value control unit  203  determines that the new registration size is secured. 
     If the new registration size is secured (YES in step S 4021 ), the setting value control unit  203  advances the processing to step S 4022 . If the new registration size is not secured (NO in step S 4021 ), the setting value control unit  203  advances the processing to step S 4018  to repeat the deletion processing. The processing in steps S 4018  to S 4021  is an example of data management processing for deleting one or more group setting information pieces registered in the setting DB  400  as the storage unit and securing a new registration size necessary for registration of the group setting information of the operator. 
     In step S 4022 , the setting value control unit  203  compares the used storage capacity in the deletion management table  504  with the used capacity threshold value. If the used storage capacity is equal to or greater than the used capacity threshold value (YES in step S 4022 ), the setting value control unit  203  advances the processing to step S 4023 . If the used storage capacity is less than the used capacity threshold value (NO in step S 4022 ), the setting value control unit  203  advances the processing to step S 4028 . In step S 4023 , the setting value control unit  203  determines whether the automatic deletion of person or the automatic deletion of group is ON. If at least one of the automatic deletion of person and the automatic deletion of group is set to ON (YES in step S 4023 ), the setting value control unit  203  advances the processing to step S 4025 . If both of the automatic deletion of person and the automatic deletion of group are OFF (NO in step S 4023 ), the setting value control unit  203  advances the processing to step S 4024 . 
     In step S 4024 , the setting value control unit  203  sets the personal setting storage flag and the group setting storage flag, which are not illustrated, to “non-storable” regarding the personal identifier obtained in step S 4004  and the group identifier obtained in step S 4005 . Accordingly, the operator falls into a state in which the operator cannot register the personal setting information and the group setting information. Then, the setting value control unit  203  advances the processing to step S 4028 . 
     In step S 4025 , the setting value control unit  203  select the personal identifier or the group identifier of which time and date of last use is the oldest based on the automatic deletion of person or the automatic deletion of group determined in step S 4023 . More specifically, if both of the automatic deletion of person and the automatic deletion of group are set ON, the setting value control unit  203  refers to both of the personal management table  502  (see  FIG. 5B ) and the group management table  503  (see  FIG. 5C ). Then, the setting value control unit  203  selects the personal identifier or the group identifier associated with the oldest time and date of last use among these tables. 
     Further, if only the automatic deletion of person is set to ON, the setting value control unit  203  refers to the personal management table  502  and selects the personal identifier associated with the oldest time and date of last use therein. Similarly, if only the automatic deletion of group is set to ON, the setting value control unit  203  refers to the group management table  503  and selects the group identifier associated with the oldest time and date of last use therein. 
     In step S 4026 , the setting value control unit  203  deletes a record corresponding to the personal identifier or the group identifier selected in step S 4025  and further deletes the setting information corresponding to the selected personal identifier or group identifier. More specifically, when selecting the personal identifier in step S 4025 , the setting value control unit  203  deletes a record corresponding to the selected personal identifier from the personal management table  502 . The setting value control unit  203  further deletes the personal setting information corresponding to the selected personal identifier from the setting DB  400 . 
     Whereas, when selecting the group identifier in step S 4025 , the setting value control unit  203  deletes a record corresponding to the selected group identifier from the group management table  503 . The setting value control unit  203  further deletes the group setting information corresponding to the selected group identifier from the setting DB  400 . Furthermore, the setting value control unit  203  updates the used storage capacity in the deletion management table  504  of the management table DB  500  according to a data size of the deleted personal setting information or group setting information. 
     In step S 4027 , the setting value control unit  203  determines whether the used storage capacity is equal to or greater than the used capacity threshold value. If the used storage capacity is equal to or greater than the used capacity threshold value (YES in step S 4027 ), there is no sufficient free space to register new setting information in the setting DB  400 , so that the setting value control unit  203  advances the processing to step S 4025  to repeat the deletion processing. If the used storage capacity is less than the used capacity threshold value (NO in step S 4027 ), the setting value control unit  203  advances the processing to step S 4028 . The processing in steps S 4022  to S 4027  is an example of data management processing for deleting one or more setting information pieces if a free space in the setting DB  400  as the storage unit is less than a threshold value and securing a new registration size necessary for registration of the setting information of the operator. 
     In step S 4028 , the authentication control unit  202  executes reflection processing of the personal setting. Next, in step S 4029 , the authentication control unit  202  notifies the operator of success of login via the display operation control unit  201  and completes the login processing. The authentication method is not limited to the above-described one, and other authentication methods, such as a method using a non-contact type integrated circuit (IC) card, can be used. 
       FIG. 8  is a flowchart illustrating logout processing. In step S 4100 , if a logout request from a user is received via the touch panel  118 , the display operation control unit  201  changes the authentication state from the login state to the non-login state. In step S 4101 , the authentication control unit  202  executes reflection processing of settings. In step S 4102 , the authentication control unit  202  notifies the user of success of logout via the display operation control unit  201  and completes the logout processing. 
     As described above, if the number of registerable personal users or the number of registerable group users reaches the upper limit, the MFP  101  according to the present exemplary embodiment automatically deletes data in the setting DB  400  when an operator logs in to the MFP. Thus, the MFP  101  can secure the storage capacity for registering setting information of a new user. A data size to be deleted is a size sufficient to register setting information of a single user. Thus, if the data deletion processing is executed after the login, then data is not deleted. Therefore, performance of job execution during the login can be prevented from deteriorating. Further, since the MFP  101  separately performs data deletion on each of the personal setting information and the group setting information, if the number of the registered group setting information exceeds the upper limit, the personal setting information is not deleted. 
     As for a modified example of the MFP  101  according to the first exemplary embodiment, upper limits of the number of personal users and the number of group users which can be registered in the setting DB  400  are not limited to the above-described exemplary embodiment. The upper limit may be, for example, a predetermined fixed value or a value obtained by multiplying the maximum number of personal users or the maximum number of group users by a certain reduction rate. 
     As for a second modified example, in step S 4022  shown in  FIG. 6B , a memory size to be secured when it is determined that the used storage capacity is equal to or greater than the used capacity threshold value is not limited to the above-described exemplary embodiment. For example, if an operator is a registered personal user (NO in step S 4006  and NO in step S 4014 ), the MFP  101  calculates a difference between the maximum data size of a single personal user and a data size already used. Then, the MFP  101  may set the calculated difference as a memory size to be secured. As described above, if a free space in the setting DB  400  as the storage unit is less than a threshold value, the MFP  101  can secure a free space equal to or greater than the threshold value at a timing when the state is shifted from the non-login state to the login state. 
       FIG. 9  illustrates an image forming system according to a second exemplary embodiment. The image forming system includes a setting server apparatus  1000 , two MFPs  1001  and  1002 , and a master setting DB  1010 . In the image forming system according to the second exemplary embodiment, a plurality of MFPs  1001  and  1002  manages personal setting information and group setting information in synchronization with each other. 
     A configuration of the image forming system illustrated in  FIG. 9  is an example, so that the image forming system may include other components or have a different configuration which can provide effects similar to the configuration in  FIG. 9 . The MFP  1001  or the MFP  1002  may include a configuration of the setting server apparatus  1000 . The master setting DB  1010  stores shared setting information, personal setting information, and group setting information. The setting server apparatus  1000  manages the master setting DB  1010 . 
     As illustrated in  FIG. 9 , the MFP  1001  and the MFP  1002  are connected to the setting server apparatus  1000  via the network  102 . When a user changes the setting information at the MFP  1001 , the setting server apparatus  1000  is notified of the changed content. On the other hand, the MFP  1002  makes an inquiry to the setting server apparatus  1000  as to whether setting is changed, and if there is any setting change, the MFP  1002  receives the setting information from the setting server apparatus  1000 . Accordingly, the content of the setting change in the MFP  1001  is reflected to the MFP  1002 . 
     Hardware configurations of the MFP  1001  and the MFP  1002  are similar to that of the MFP  101  according to the first exemplary embodiment. Regarding software configurations and processing of the MFP  1001  and the MFP  1002 , points different from those of the MFP  101  according to the first exemplary embodiment are described below. 
       FIG. 10  illustrates the software configuration of the MFPs  1001  and  1002  according to the second exemplary embodiment. The MFPs  1001  and  1002  according to the second exemplary embodiment include a synchronization control unit  205  in addition to the software configuration of the MFP  101  according to the first exemplary embodiment. The synchronization control unit  205  communicates with the setting server apparatus  1000  via the communication I/F controller  117 . The synchronization control unit  205  performs control to synchronize a setting value stored in the setting DB  400  with a setting value stored in the master setting DB  1010  on the setting server apparatus  1000 . 
     The MFPs  1001  and  1002  execute login processing (see  FIGS. 6A and 6B ) similar to the MFP  101  according to the first exemplary embodiment. More specifically, if at least one of the automatic deletion of person and the automatic deletion of group is set to ON, the MFPs  1001  and  1002  execute the automatic deletion processing of the setting information at a timing when the state is shifted from the non-login state to the login state. 
       FIG. 11  is a sequence diagram illustrating master setting DB update processing by the image forming system. In the master setting DB update processing, if the setting information in the setting DB  400  is changed (registered, updated, or deleted), the MFP  1001  notifies the setting server apparatus  1000  of a changed content. The setting server apparatus  1000  then changes the setting information in the master setting DB  1010  according to the changed content. Accordingly, the setting DB  400  in the MFP  1001  can be synchronized with the master setting DB  1010 . The setting change is executed, in response to an instruction from an operator, by any of the function control units including the copy control unit  210 , the scan control unit  211 , the transmission control unit  212 , and function units not illustrated. 
     In step S 1001 , when the changed content of the setting information is received from each function control unit, the setting value control unit  203  updates the setting DB  400  according to the changed content. In step S 1002 , if the setting change fails (NO in step S 1002 ), the setting value control unit  203  advances the processing to step S 1003 . Then, in step S 1003 , each function control unit notifies the operator of a failure in the setting change. If the setting change is successful (YES in step S 1002 ), the setting value control unit  203  requests the synchronization control unit  205  to notify the setting server apparatus  1000  of the content of the setting change. Then, in step S 1004 , the synchronization control unit  205  transmits a change instruction including the content of the setting change to the setting server apparatus  1000  via the network  102 . The processing in step S 1004  is an example of transmission processing for transmitting a change instruction. 
     In step S 1005 , if communication with the setting server apparatus  1000  is successful (YES in step S 1005 ), the synchronization control unit  205  advances the processing to step S 1008 . If communication with the setting server apparatus  1000  fails (NO in step S 1005 ), the synchronization control unit  205  advances the processing to step S 1004  to retry the communication with the setting server apparatus  1000 . 
     In step S 1006 , when the change instruction is received, the setting server apparatus  1000  updates the master setting DB  1010  according to the content of the setting change. Then, in step S 1007 , the setting server apparatus  1000  transmits to the MFP  1001  a success notification indicating that the master setting DB  1010  is successfully updated. 
     In step S 1008 , the MFP  1001  waits to receive the success notification. When the success notification is received (YES in step S 1008 ), then in step S 1009 , each function control unit in the MFP  1001  notifies the operator of success of the setting change. Thus, setting change notification processing is completed. 
       FIG. 12  is a flowchart illustrating setting DB update processing by the MFP  1002 . The MFP  1002  executes the setting DB update processing when an operator logs in to and out from the MFP  1002 . An execution timing of the setting DB update processing is not limited to the one in the present exemplary embodiment. The MFP  1002  may execute the setting DB update processing, for example, regularly. As for another example, the MFP  1002  may execute the setting DB update processing at a specified time which is set in advance. 
     A case is described as an example in which the setting DB  400  in the MFP  1002  is updated according to the master setting DB  1010  which is updated according to the change of the setting information in the MFP  1001 . The setting value control unit  203  in the MFP  1002  transmits a request to start synchronization processing to the synchronization control unit  205 . In step S 1101 , the synchronization control unit  205  transmits a last synchronization time to the setting server apparatus  1000  in response to synchronization request. In step S 1102 , if communication with the setting server apparatus  1000  fails (NO in step S 1102 ), the synchronization control unit  205  advances the processing to step S 1107 . In step S 1107 , the synchronization control unit  205  determines whether the processing can be retried. If the processing can be retried (YES in step S 1107 ), the synchronization control unit  205  advances the processing to step S 1101 . If the processing cannot be retried (NO in step S 1107 ), the synchronization control unit  205  completes the setting DB update processing. 
     In step S 1102 , if it is determined that communication with the setting server apparatus  1000  in step S 1101  is successful (YES in step S 1102 ), the synchronization control unit  205  advances the processing to in step S 1103 . Then, in step S 1103 , the synchronization control unit  205  requests the setting server apparatus  1000  to transmit a difference of the setting information pieces between the one of the last synchronization time and the one changed after the last synchronization time. 
     In step S 1104 , if it is determined that communication with the setting server apparatus  1000  in step S 1103  is successful (YES in step S 1104 ), the synchronization control unit  205  receives the difference of the setting information from the setting server apparatus  1000 . Then, in step S 1105 , the setting value control unit  203  updates the setting DB  400  based on the difference of the setting information. If it is determined that communication with the setting server apparatus  1000  in step S 1103  fails (NO in step S 1104 ), the synchronization control unit  205  advances the processing to step S 1107 . 
     In step S 1106 , if it is determined that reflection of the difference of the setting data to the setting DB  400  in step S 1105  fails (NO in step S 1106 ), the setting value control unit  203  advances the processing to step S 1107 . If it is determined that reflection of the difference of the setting data to the setting DB  400  in step S 1105  is successful (YES in step S 1106 ), the setting value control unit  203  completes the setting DB update processing. 
     The MFP  1002  may execute the setting DB update processing separately (at different timings) on each of the shared setting information, the personal setting information, and the group setting information. In addition, synchronization of only specific setting information may be started at a timing different from others. 
     As described above, the image forming system according to the present exemplary embodiment can share the setting information among a plurality of MFPs by utilizing the setting server apparatus  1000  provided outside the MFPs. 
     In the image forming system, the setting information stored in the master setting DB  1010  of the setting server apparatus  1000  and the setting information stored in the setting DB  400  of each MFP can be respectively regarded as master data and a cache. In other words, if the personal setting information or the group setting information in each MFP is deleted, when master data exists in the setting server apparatus  1000 , each MFP can obtain the master data by the setting DB update processing (see  FIG. 12 ). 
     On the other hand, if the master setting DB  1010  is updated in the master setting DB update processing in response to the automatic deletion in the MFP, the master data is also deleted. Thus, the MFP which does not execute the automatic deletion also becomes unable to use the setting information subjected to the automatic deletion. 
     The processing is described in detail below. As assumption, an operator A uses both of the MFP  1001  and the MFP  1002  in the configuration of the image forming system illustrated in  FIG. 9 . In the setting DB  400  in the MFP  1001 , a time and date of use by the operator A is the oldest, and the number of personal users reaches the upper limit. The automatic deletion of person is set to ON in the MFP  1001 . Further, the setting server apparatus  1000  stores the personal setting information of the operator A. 
     If a new operator X logs in to the MFP  1001  in this state, the personal setting information of the oldest operator A is deleted. When a change instruction in response to the deletion is transmitted to the setting server apparatus  1000 , and the master setting DB  1010  is to be updated, the personal setting information of the operator A stored in the master setting DB  1010  is deleted. 
     In order to avoid such a situation, when an instruction associated with the setting server apparatus  1000  is issued to the synchronization control unit  205 , the MFP according to the present exemplary embodiment causes the setting value control unit  203  to forcibly set the automatic deletion of person and the automatic deletion of group to ON. Further, the MFP does not allow the synchronization control unit  205  to change the settings of the automatic deletion of person and group until an instruction to dissolve the association with the setting server apparatus  1000  is issued. 
     Furthermore, in the case that deletion of the personal setting information and the group setting information are executed in step S 4012 , step S 4020 , and step S 4026 , which are described with reference to  FIGS. 6A and 6B  according to the first exemplary embodiment, the MFP does not executes the master setting DB update processing ( FIG. 11 ). More specifically, if the automatic deletion processing of the setting information is executed to secure a new registration size, the setting value control unit  203  prohibits transmission of the change instruction of the setting information corresponding to the deletion to the setting server apparatus  1000  (update control processing). 
     As described above, when the MFP synchronizes the setting information with the setting server apparatus  1000  in the image forming system according to the present exemplary embodiment, the automatic deletion of the setting information is forcibly validated. Accordingly, if an administrator forgets to set the automatic deletion, the personal and the group setting information pieces can be efficiently managed. Further, the image forming system does not update the master setting DB  1010  in response to the deletion of the setting information by the automatic deletion processing in the MFP. Therefore, if setting information of a certain user is deleted in an MFP, the setting information of the certain user is not deleted in another MFP. 
     According to each of the above-described exemplary embodiments, data deletion processing can be executed to secure a storage capacity for registering setting information without deteriorating performance of other job execution. 
     Embodiment(s) of the present invention can also be realized by a computer of a system or apparatus that reads out and executes computer executable instructions (e.g., one or more programs) recorded on a storage medium (which may also be referred to more fully as a ‘non-transitory computer-readable storage medium’) to perform the functions of one or more of the above-described embodiment(s) and/or that includes one or more circuits (e.g., application specific integrated circuit (ASIC)) for performing the functions of one or more of the above-described embodiment (s), and by a method performed by the computer of the system or apparatus by, for example, reading out and executing the computer executable instructions from the storage medium to perform the functions of one or more of the above-described embodiment(s) and/or controlling the one or more circuits to perform the functions of one or more of the above-described embodiment(s). The computer may comprise one or more processors (e.g., central processing unit (CPU), micro processing unit (MPU)) and may include a network of separate computers or separate processors to read out and execute the computer executable instructions. The computer executable instructions may be provided to the computer, for example, from a network or the storage medium. The storage medium may include, for example, one or more of a hard disk, a random-access memory (RAM), a read only memory (ROM), a storage of distributed computing systems, an optical disk (such as a compact disc (CD), digital versatile disc (DVD), or Blu-ray Disc (BD)™), a flash memory device, a memory card, and the like. 
     While the present disclosure has been described with reference to exemplary embodiments, it is to be understood that these exemplary embodiments are not seen to be limiting. 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.