Patent Publication Number: US-2020278817-A1

Title: Image forming system, image forming apparatus, output method, and storage medium

Description:
BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present disclosure relates to an image forming system, an image forming apparatus, an output method, and a storage medium. 
     Description of the Related Art 
     Conventional multifunction peripherals immediately perform printing upon receiving a print job from a terminal apparatus such as a personal computer (PC). In this case, there is a possibility that an information leak will occur as a result of the printed matter being left behind or a third party seeing the uncollected printed matter. Therefore, in recent years, in order to maintain confidentiality, hold printing has been proposed in which a print job is retained in a nonvolatile storage area, without being printed, upon having been received, and printing is performed thereafter when a print instruction is given from a user through an operation unit of a multifunction peripheral (Japanese Patent Laid-Open No. 2007-251279). 
     Also, in recent years, remote hold printing has been proposed in which printing can be performed not only by acquiring a print job from a multifunction peripheral that received the print job but also by acquiring a print job from another multifunction peripheral that retains the print job (Japanese Patent Laid-Open No. 2010-211627). 
     There are cases in which hold printing is used when printing is performed using a multifunction peripheral that is usually used by a user, and remote hold printing is used when printing is performed using a multifunction peripheral that is not usually used by a user, depending on the congestion state of the multifunction peripherals, for example. 
     However, in conventional technologies, if the above-described hold printing and remote hold printing are dynamically switched in response to an operation made by a user to a multifunction peripheral, in the case of remote hold printing, print jobs need to be acquired from multifunction peripherals that are targets of the remote hold printing, and it takes a long time to display a document list. A mechanism is required that enables the user to display and print printing targets stress-free regardless of which of hold printing and remote hold printing is selected under a circumstance in which both types of printing are supported. 
     SUMMARY OF THE INVENTION 
     The present disclosure was made in view of the above-described conventional examples, and it is one object of the present disclosure to provide a mechanism that makes it possible to display and print printing targets stress-free even if remote hold printing is selected. Also, one object of another aspect of the present disclosure is to enhance the convenience of a hold printing function. 
     In order to achieve the above-described objects, one aspect of the present invention is an image forming system comprising a document receiving apparatus, an output apparatus, and a bibliography server, the document receiving apparatus comprising: a first memory storing first instructions; and a first processor which is capable of executing the first instructions causing the document receiving apparatus to accept and store print jobs, the bibliography server comprising: a second memory storing second instructions; and a second processor which is capable of executing the second instructions causing the bibliography server to receive bibliographic information that includes a storage location of each print job from the document receiving apparatus and store the bibliographic information, and the output apparatus comprising: a third memory storing third instructions; and a third processor which is capable of executing the third instructions causing the output apparatus to: acquire the bibliographic information from the bibliography server; in response to an instruction for remote hold printing, display the bibliographic information as a list of print jobs that are output targets; and acquire a print job selected from the list, from the storage location and execute the print job. 
     Another aspect of the present invention is an image forming apparatus configured to function as an output apparatus that is connected to a document receiving apparatus that accepts and stores print jobs and a bibliography server that receives bibliographic information including a storage location of each print job from the document receiving apparatus and stores the bibliographic information, the image forming apparatus comprising: a memory storing instructions; and a processor which is capable of executing the instructions causing the image forming apparatus to: acquire the bibliographic information from the bibliography server; display, in response to an instruction for remote hold printing, the acquired bibliographic information as a list of print jobs that are output targets; and acquire, in response to an instruction, a print job selected from the list, from the storage location and execute the print job. 
     Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagram showing a network configuration of a remote hold printing system. 
         FIG. 2  is a block diagram showing a schematic configuration of a multifunction peripheral. 
         FIG. 3  is a block diagram showing a software configuration of a multifunction peripheral. 
         FIG. 4  shows one example of icon buttons for hold printing and remote hold printing, which are displayed by a multifunction peripheral. 
         FIGS. 5A and 5B  respectively show one example of a document list screen of hold printing and one example of a document list screen of remote hold printing, which are displayed by a multifunction peripheral. 
         FIGS. 6A to 6C  are block diagrams showing an actual form of bibliographic information stored in an output apparatus. 
         FIG. 7  is a block diagram showing a saving format of bibliographic information stored in an output apparatus according to Embodiment 1. 
         FIG. 8  is a flow chart showing one exemplary procedure of processing performed by a document receiving apparatus according to Embodiment 1. 
         FIG. 9  is a flow chart showing one exemplary procedure of document list display processing performed by the output apparatus according to Embodiment 1. 
         FIG. 10  is a flow chart showing one exemplary procedure of processing performed by a bibliography server apparatus according to Embodiment 1. 
         FIG. 11  is a flow chart showing one exemplary procedure of printing performed by the output apparatus according to Embodiment 1. 
         FIG. 12  is a flow chart showing one exemplary procedure of print data transmission performed by the document receiving apparatus according to Embodiment 1. 
         FIG. 13  is a block diagram showing a saving format of bibliographic information stored in an output apparatus according to Embodiment 2. 
         FIG. 14  is a flow chart showing one exemplary procedure of document list display processing performed by the output apparatus according to Embodiment 2. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     The following describes embodiments of the present disclosure with reference to the drawings. 
     Embodiment 1 
     Network Configuration of Remote Hold Printing System 
       FIG. 1  is a diagram showing a network configuration to which a multifunction peripheral that is an image forming apparatus according to Embodiment 1 of the present disclosure can be applied. In  FIG. 1 , a network  101  supports TCP/IP protocols, for example. A personal computer  102 , which is an information processing apparatus, and multifunction peripherals  103  to  105  are connected to the network  101 . 
     For example, the multifunction peripheral  103  is a document receiving apparatus that, upon receiving a print job from the personal computer  102 , performs printing or stores (in other words, saves or retains) print data that is included in the print job to perform printing later. The multifunction peripheral  103  extracts bibliographic information from the received print job and transmits the extracted bibliographic information to the multifunction peripheral  104 . The multifunction peripheral  104  is a bibliography server apparatus (also referred to as a “bibliography server”) that unitarily manages bibliographic information regarding print data stored in other multifunction peripherals. The multifunction peripheral  105  is a document receiving apparatus that receives print jobs, and also functions as an output apparatus that acquires bibliographic information from the bibliography server apparatus  104  based on authentication information, receives retained print data from the document receiving apparatus  103  based on the acquired bibliographic information, and performs printing. 
     The above-described configuration is a general configuration described to facilitate understanding, and it goes without saying that it is also possible to employ a configuration including a plurality of personal computers  102 , a plurality of document receiving apparatuses  103 , and/or a plurality of document receiving apparatuses/output apparatuses  105 . Also, the multifunction peripherals  103  to  105  each operate as both a document receiving apparatus and an output apparatus. That is, each multifunction peripheral in this system operates as both a document receiving apparatus and an output apparatus, and one of the multifunction peripherals operates as a bibliography server apparatus. 
     Schematic Configuration of Multifunction Peripherals  103  to  105   
       FIG. 2  is a block diagram showing a schematic configuration of each of the multifunction peripherals  103 ,  104 , and  105  according to Embodiment 1 of the present disclosure. The multifunction peripheral  103  will be described with reference to  FIG. 2  to simplify the description. 
     In  FIG. 2 , the multifunction peripheral  103  is constituted by a controller unit  200 , an operation unit  206 , a scanner unit  208 , and a printer unit  209 . 
     The controller unit  200  is an apparatus that controls the multifunction peripheral or printer. The controller unit  200  is constituted by a CPU  201 , a RAM  202 , a ROM  203 , a HDD  204 , an operation unit I/F  205 , a device I/F  207 , and a network I/F  210 , which are connected to each other via a system bus  211 . 
     The CPU  201  controls the entire image forming apparatus  103  by comprehensively controlling the apparatuses connected to the system bus  211 . Programs, such as an operating system, system software, and application software, and data are stored in the RAM (Random Access Memory)  202 . A boot program for a system, a system program, and application programs are stored in the ROM (Read Only Memory)  203 . In some cases, information that is necessary for the image forming apparatus, such as fonts, is also stored. The HDD  204  is a hard disk drive in which the operating system, system software, application software, image data, settings data, etc. are stored. Hold printing jobs may also be stored in the HDD  204 . Further, if the image forming apparatus  103  functions as a bibliography server, bibliographic information may also be stored in the HDD  204 . Note that bibliographic information can also be stored as an in-memory database on the RAM  202  to increase the processing speed. The programs stored in the RAM  202  are executed by the CPU (Central Processing Unit)  201  to process image data and data other than images, which are stored in the RAM  202 , the ROM  203 , or the HDD  204 . In the case of a small multifunction peripheral, a configuration is sometimes employed in which the HDD  204  is not provided and system software, application software, etc. are stored in the ROM  203 . Alternatively, a configuration is also possible in which a storage device other than a hard disk, for example, an SSD (Solid State Disk) using a flash memory, is used instead of the HDD  204 . 
     The operation unit I/F  205  is an interface unit interfaced to the operation unit  206  that includes a touch panel, and outputs image data to be displayed in the operation unit  206  to the operation unit  206 . Also, the operation unit I/F  205  transmits information input by the user through the operation unit  206  to the CPU  201 . The operation unit  206  displays, for example, a user interface screen on the touch panel. It is possible to display, on the user interface, a list of bibliographic information regarding hold printing jobs and a list of bibliographic information acquired from the bibliography server, for example. Print jobs can be identified using bibliographic information, and accordingly a list of bibliographic information displayed on the user interface can also be called a list of print jobs. 
     The device I/F  207  connects the scanner unit  208  and the printer unit  209 , which are image input/output devices, to the controller unit  200 , and inputs or outputs image data. Image data input from the scanner unit  208  through the device I/F  207  is stored in the RAM  202  or the HDD  204 . Image processing or the like is performed on the stored image data as necessary, using application programs stored in the RAM  202 . Also, image data is output through the device I/F  207  to the printer unit  209 . The network I/F  210  is connected to a network, and image data or information for controlling the multifunction peripheral is input from or output to external devices on the network via the network I/F  210 . 
     It goes without saying that there is no limitation to the configuration shown in  FIG. 2 , and a configuration other than that shown in  FIG. 2  can also be employed so long as the effects of the present disclosure can be achieved. For example, in the case of a multifunction peripheral that has a facsimile (FAX) function, a configuration is also possible in which the controller unit  200  includes an I/F for a modem apparatus, which is not shown in  FIG. 2 , and FAX transmission is enabled by establishing a connection to a public line using a modem. Alternatively, the controller unit  200  may also include a Universal Serial Bus (USB) I/F (not shown) to enable reading and printing of data that is stored in a flash memory card etc., for example. 
     Software Configuration of Multifunction Peripherals  103  to  105   
       FIG. 3  is a block diagram showing a software configuration of each of the multifunction peripherals  103  to  105  according to Embodiment 1 of the present disclosure, which is implemented in the controller unit  200 . Software that is incorporated in the multifunction peripheral or printer and is processed by the controller unit  200  is installed as so-called firmware, and is executed by the CPU  201 . 
     Real time OS  301  provides software that runs on the real time OS  301  with services and frameworks for various types of resource management, which are optimized to control embedded systems. The services and frameworks for various types of resource management provided by the real time OS include multi-task management for running a plurality of processes substantially in parallel by managing a plurality of execution contexts of processes performed by the CPU  201 , and inter-task communication that realizes synchronization and data exchange between tasks. Further, the real time OS  301  also provides memory management, interruption management, various device drivers, and a protocol stack in which processes of various protocols for a local interface, a network, communication, etc. are implemented, for example. 
     A controller platform  302  is constituted by a file system  303 , job/device control  304 , a counter  305 , etc. The file system  303  is a mechanism for storing data constructed on a storage device, such as the HDD  204  or the RAM  202 , and is used to spool jobs to be handled by the controller unit  200  or store various types of data. The job/device control  304  controls hardware of the multifunction peripheral or printer, and mainly controls jobs that use basic functions (printing, scanning, communication, image transformation, etc.) provided by the hardware. The counter  305  manages the expiration date of each application and counter values of printing and scanning. 
     A system service  306  is a module for monitoring the operation state of the multifunction peripheral or printer and downloading software and a license from a software distribution server via a network. An application platform  307  is middleware that enables use of the real time OS  301  and the mechanism of the controller platform  302  from a system application  308 , which is described below, or applications  312  that can be added. 
     The system application  308  is constituted by an authentication service  309 , access control  310 , and bibliographic information management  311 . The authentication service  309  performs user authentication by checking a user name and a password that are input through the operation unit  206  or a network against a user database that is stored in the HDD  204 . It is also possible to perform authentication using an external authentication server, such as ActiveDirectory, rather than holding a user database in the HDD  204 . The access control  310  is a security module for permitting or forbidding jobs or access to various resources, based on user authority or security settings that are set for data. The bibliographic information management  311  is a module that is implemented in the bibliography server apparatus, the document receiving apparatus, and the output apparatus, and manages, with respect to each user, bibliographic information regarding print data that is stored in multifunction peripherals that are connected to each other via a network. Bibliographic information includes information regarding print data (document) that is input to a multifunction peripheral, such as the received date/time of the print data, the IP address of the multifunction peripheral storing the print data or a directory path in a local device, print data name, print settings, etc. 
     Each application  312  is a module that is capable of displaying a menu in the operation unit  206  and accepting input from the user, and provides the user with various functions that are realized by the multifunction peripheral or printer. A hold printing application  313  is one of the applications  312 , and displays a document list that shows a list of hold printing data, deletes print data, performs retention determination upon receiving print jobs, and performs print output processing, etc. A remote hold printing application  314  is one of the applications  312 , and has the functions of the hold printing application  313  as well as a function that enables display and operation of not only a list of print data retained in the multifunction peripheral that is being operated, but also a list of print data retained in other multifunction peripherals. 
     Description of Application Selection Screen 
       FIG. 4  shows one example of an application selection screen that is displayed in the multifunction peripheral  105 , which is an output apparatus according to Embodiment 1. This screen is displayed in the operation unit  206  of the multifunction peripheral  105 . 
     After a user logs in to the multifunction peripheral  105  using an IC card or the like, a top menu  400  is displayed to allow the user to select an application to be used, from the top menu  400 . Since the user has logged in to the multifunction peripheral  105 , a logged in user name  404  is displayed on the screen. In the illustrated example of the screen, the user name “Sato” is displayed in the login state. 
     The top menu  400  displays icons for respective applications  312 . A print icon  401  is the icon for the hold printing application  313 , and the hold printing application  313  is activated as a result of the print icon  401  being touched. Note that, although operations made on a touch panel are mainly made by touching the touch panel, an operation made by touching the touch panel is also referred to as “pressing” in the present embodiment. A remote print icon  402  is the icon for the remote hold printing application  314 , and the remote hold printing application  314  is activated as a result of the remote print icon  402  being touched. A setting icon  403  is the icon for an application for performing setting regarding the multifunction peripheral  105 , the application being one of the applications  312 . 
     Description of Document List Screen 
       FIGS. 5A and 5B  each show one example of a document list screen that is displayed in the multifunction peripheral  105 , which is the output apparatus according to Embodiment 1. These screens are displayed in the operation unit  206  by the hold printing application  313  and the remote hold printing application  314 , which are executed by the CPU  201  of the multifunction peripheral  105 . The document list screen displays a list of print jobs or a list of print data that is held by an authenticated user. Print jobs or print data displayed on the document list screen indicates documents (or print jobs) that can be output targets (or printing targets). 
       FIG. 5A  shows a document list screen of the hold printing application  313 , which is displayed as a result of the print icon  401  being touched. A document list is created based on bibliographic information that is stored in the HDD  204  in step S 813  in  FIG. 8 . In the illustrated example of the screen, the user name “Sato” is displayed in the login state. With respect to each document list, a thumbnail  501 , a job name  502 , received date/time  503 , number of pages x number of copies  504 , and a user name  505  are displayed. Two pieces of print data ( 506  and  507 ) can be printed or deleted via this screen. The hold printing application  313  can display only print data that is stored in the multifunction peripheral being operated, and accordingly the two pieces of data are stored in the HDD  204  of the multifunction peripheral  105 .  509  denotes a delete button,  510  denotes a print start button, and, as a result of the user selecting desired print data from the list and pressing one of these buttons, the target print data is deleted or printed.  508  denotes a logged in user. 
       FIG. 5B  shows a document list screen of the remote hold printing application  314 , which is displayed as a result of the remote print icon  402  being touched. A document list is created based on bibliographic information that is stored in the HDD  204  in step S 910  in  FIG. 9 . In the illustrated example of the screen, the user name “Sato” is displayed in the login state. With respect to each document list, a thumbnail  521 , a job name  522 , received date/time  523 , number of pages x number of copies  524 , and a user name  525  are displayed. Four pieces of print data ( 526  to  529 ) can be printed or deleted via this screen. The remote hold printing application  314  can also display print data stored in the multifunction peripheral being operated, and accordingly the four pieces of data are stored in the HDD  204  of the multifunction peripheral  105  and the HDD  204  of the multifunction peripheral  103 .  531  denotes a delete button,  532  denotes a print start button, and, as a result of the user selecting desired print data from the list and pressing one of these buttons, the target print data is deleted or printed.  530  denotes a logged in user. 
     Actual Form of Bibliographic Information 
       FIGS. 6A to 6C  are diagrams showing one example of an actual form of bibliographic information that is managed with respect to each user by the bibliographic information management  311 . 
       FIG. 6A  shows four pieces of bibliographic information as an example of bibliographic information that is managed by the bibliographic information management  311  of the bibliography server apparatus  104 . These pieces of bibliographic information are created by the document receiving apparatuses  103  and  105 , transmitted to the bibliography server apparatus  104 , and managed by the bibliography server apparatus  104 . That is, the bibliography server apparatus  104  manages bibliographic information regarding all print data retained in multifunction peripherals that are included in the system and support remote hold printing. Bibliographic information  601  includes a user name  603 , a bibliography ID  612 , received date/time  604 , a storage IP address  605 , a directory path  605 , a job name  607  of print data, a paper size  608 , page aggregation  609 , number of pages  610 , and number of copies  611 . Here, bibliographic information regarding a user who has the user name  603  “Sato” is shown. The received date/time  604  is information that indicates the date and time at which a pint job was received. The storage IP address  605  indicates the IP address of a multifunction peripheral that stores print data, and the directory path  606  indicates the path to a directory in which the print data is stored. That is, the storage IP address  605  and the directory path  606  are information for specifying the storage location (or saving location) of the print data. Print settings  608  to  611  are set through a printer driver using an application that runs on the personal computer  102 . It goes without saying that other print settings may also be held. A configuration is also possible in which bibliographic information includes a print finished flag that indicates whether or not print data has already been printed, although this is not shown in  FIGS. 6A to 6C . 
       FIG. 6B  shows two pieces of bibliographic information as an example of bibliographic information that is managed by the bibliographic information management  311  of the document receiving apparatus  103 .  FIG. 6C  shows two pieces of bibliographic information as an example of bibliographic information that is managed by the bibliographic information management  311  of the document receiving apparatus/output apparatus  105 . 
     The bibliography server apparatus  104  collects bibliographic information from each multifunction peripheral and accordingly holds bibliographic information stored in the document receiving apparatus  103  and the document receiving apparatus/output apparatus  105 , but the document receiving apparatus  103  and the document receiving apparatus/output apparatus  105  are not bibliography server apparatuses and accordingly store only bibliographic information regarding print jobs that they themselves have received (i.e., that have been input to themselves). Therefore, IP addresses  625  and  645  of the multifunction peripherals storing print data are displayed as “localhost”, which indicates a loopback address, and the management target is bibliographic information regarding print jobs stored in the self apparatus. 
     Saving Format of Bibliographic Information 
       FIG. 7  is a diagram showing one example of a saving format of bibliographic information stored in each multifunction peripheral. A bibliographic information list  701  shows the saving format of bibliographic information stored in the bibliography server apparatus  104 , and includes the user name  603  “Sato” as the head node and four pieces of bibliographic information that are respectively created in the multifunction peripherals, transmitted to the bibliography server apparatus, and stored under the head node. A bibliographic information list  702  shows the saving format of bibliographic information stored in the document receiving apparatus  103 , and includes the user name  623  “Sato” as the head node and bibliographic information regarding two pieces of print data input to the document receiving apparatus  103 , which is stored under the head node. A bibliographic information list  703  shows the saving format of bibliographic information stored in the document receiving apparatus/output apparatus  105 , and includes the user name  643  “Sato” as the head node and bibliographic information regarding two pieces of print data input to the document receiving apparatus/output apparatus  105 , which is stored under the head node. 
     Print Job Transmission Procedure 
     The following describes one example of a procedure that is executed when a print job is transmitted by the user from the personal computer  102  to the multifunction peripheral  103 , which is the document receiving apparatus. In the following description, assume that authentication management is performed by the authentication service  309  in the multifunction peripheral  103 . 
     In the present embodiment, an example will be described in which Page Description Language (PDL) data is transmitted as print data to the multifunction peripheral  103 . Examples of PDLs include Printer Command Language (PCL) and PostScript (registered trademark) of Adobe Inc., and the multifunction peripheral  103  performs printing by analyzing the PDL and performing Raster Image Processing (RIP processing). Note that print data is only required to have a format that can be analyzed and printed by the multifunction peripheral  103 , and may have a format other than PDL data, for example, image data, such as TIFF, or a document format of an application. 
     The user activates the printer driver using an application that runs on the personal computer  102 . The user sets print settings using a printer driver screen (not shown), and then selects the multifunction peripheral  103  and gives a print instruction. Here, the user can also give an explicit instruction for hold printing. 
     Upon accepting the print instruction, the printer driver displays an authentication screen (not shown). The user inputs authentication information and then gives a print instruction. The printer driver transmits an authentication request together with a user name and a password to the multifunction peripheral  103 . The authentication service  309  of the multifunction peripheral  103  checks the received user name and password, and transmits an authentication result to the personal computer. The printer driver receives the authentication result, and if the authentication is not successful, ends print processing with an error. 
     If the authentication is successful, the printer driver creates print data by converting application data into the PDL. Further, the printer driver creates a print job by including user information and designated print settings in the print data. The printer driver transmits the created print job to the multifunction peripheral  103 . 
     Here, if the personal computer  102  and the multifunction peripheral  103  are in the same authentication domain and the result of authentication performed by the personal computer  102  is guaranteed, a configuration is also possible in which the authentication request is not issued to the multifunction peripheral  103  and user information held by the personal computer  102  is used. Alternatively, a configuration is also possible in which authentication processing performed by the printer driver is omitted and user information that is registered in the printer driver in advance is used. 
     Print Job Receiving Procedure 
       FIG. 8  is a flow chart showing one exemplary procedure of print job receiving processing that is executed by the CPU  201  of the multifunction peripheral  103  or  105 , which is a document receiving apparatus according to Embodiment 1. S 801  to S 815  denote steps. 
     First, in step S 801 , the job/device control  304  waits to receive a print job. In step S 802 , upon receiving a print job via the network I/F  207 , the job/device control  304  notifies the hold printing application  313 . 
     In step S 803 , the hold printing application  313  divides the received print job into print data that is constituted by the PDL and is the target of rendering and attribute data that includes user information and designated print settings. 
     In step S 804 , the hold printing application  313  analyzes the separated attribute data. In step S 805 , the hold printing application  313  refers to the attribute data and determines whether or not retention is designated. If it is determined in step S 805  that retention is designated, processes in step S 811  and the following steps are performed. 
     If it is determined in step S 805  that retention is not designated, the hold printing application  313  determines, in step S 806 , whether or not the multifunction peripheral  103  is in a forced hold mode. If the multifunction peripheral  103  is not in the forced hold mode, processes in step S 809  and the following steps are performed. The forced hold mode is, for example, a setting of the document receiving apparatus for storing (retaining) received print jobs in principle regardless of retention setting values of the print jobs. The forced hold mode may be set via a settings screen that is displayed as a result of the setting icon  403  being touched, for example. 
     If it is determined in step S 806  that the multifunction peripheral  103  is in the forced hold mode, the hold printing application  313  checks forced retention exception conditions of the multifunction peripheral  103  in step S 807 . 
     In step S 808 , the hold printing application  313  determines whether or not the forced retention exception conditions are satisfied, based on the type of PDL constituting the print data included in the received print job or information regarding the source of the print request. If the exception conditions are satisfied, printing is performed without retaining the print data, and accordingly the processing advances to print processing that is performed in step S 809  and the following steps. 
     In step S 809 , the job/device control  404  performs RIP processing on the PDL data, which is the print data, in accordance with print settings, and performs printing in step S 810  by giving a print instruction to the printer unit  209  via the device I/F  207 . 
     If it is determined in step S 808  that the forced retention exception conditions are not satisfied, in step S 811 , the hold printing application  313  stores the print data received in step S 802  in the HDD  204  of the multifunction peripheral  103 . 
     In step S 812 , the hold printing application  313  creates bibliographic information (described with reference to  FIGS. 6A to 6C ) based on attribute data. 
     In step S 813 , the hold printing application  313  stores the created bibliographic information in the HDD  204  of the multifunction peripheral  103 . 
     In step S 814 , the hold printing application  313  transmits a request for registering the created bibliographic information to the bibliography server apparatus  104 . Upon receiving the request, the bibliography server apparatus  104  stores the received bibliographic information (see  FIG. 6A ). 
     In step S 815 , the hold printing application  313  returns to the state of waiting to receive a print job. 
     Thus, a series of processes that are performed when receiving a document ends. 
     Document List Display Procedure 
       FIG. 9  is a flow chart showing one exemplary procedure of document list display processing that is executed by the CPU  201  of the multifunction peripheral  105 , which is the document receiving apparatus/output apparatus according to Embodiment 1. S 901  to S 911  denote steps. 
     First, in step S 901 , the authentication service  309  displays an authentication screen (not shown) and waits for authentication information to be input. Upon accepting input of authentication information from the user, the operation unit  206  transmits the authentication information to the authentication service  309  via the operation unit I/F  205  (step S 902 ). 
     In step S 902 , the authentication service  309  performs user authentication. In step S 903 , it is determined whether or not the authentication was successful, and if it is determined that the authentication was successful, the authentication service  309  notifies each application  312  of the authentication result, and processes in step S 904  and the following steps are performed. If it is determined in step S 903  that the authentication was not successful, the processing returns to the process performed in step S 901 . 
     In step S 904 , the hold printing application  313  or the remote hold printing application  314  is activated as a result of the print application icon  401  or  402  being touched by the user. 
     In step S 905 , the processing advances to step S 907  if the hold printing application  313  has been activated, or the processing advances to step S 908  if the remote hold printing application  314  has been activated. 
     In step S 908 , the remote hold printing application  314  connects to the bibliography server apparatus  104  via a network using authenticated user information. 
     In step S 909 , the remote hold printing application  314  requests bibliographic information regarding the authenticated user from the connected bibliography server apparatus  104 , and acquires the bibliographic information from the bibliography server apparatus  104 . For example, if the user name of the logged in user is “Sato”, a request for bibliographic information regarding the user “Sato” is given to the bibliography server apparatus  104 , and bibliographic information associated with the user name  603  “Sato” is acquired out of the bibliographic information shown in  FIGS. 6A to 6C . 
     In step S 910 , the remote hold printing application  314  stores, in the HDD  204 , the bibliographic information regarding the authenticated user, which has been acquired from the bibliography server apparatus  104 , under the user name  643  “Sato”, which is the head node. 
     In step S 907 , the hold printing application  313  or the remote hold printing application  314  acquires bibliographic information that includes the user name  643  “Sato” as the head node. At this time, the remote hold printing application  314  acquires the bibliographic information including the bibliographic information that has been acquired from the bibliography server apparatus  104  and stored in step S 910 . 
     In step S 911 , the hold printing application  313  or the remote hold printing application  314  displays, in the operation unit  206 , a list (document list)  500  or  520  of print data that can be printing targets and deletion targets, based on the acquired bibliographic information, and then ends a series of processes. 
     Bibliographic Information Processing Procedure Executed by Bibliography Server Apparatus 
       FIG. 10  is a flow chart showing one exemplary procedure of bibliographic information management that is executed by the CPU  201  of the multifunction peripheral  104 , which is the bibliography server apparatus according to Embodiment 1. S 1001  to S 1015  denote steps. 
     First, in step S 1001 , the remote hold printing application  314  running on the CPU  201  of the multifunction peripheral  104  waits for a request to be issued from the multifunction peripheral  103 ,  104 , or  105 , regarding bibliographic information. 
     In step S 1002 , the remote hold printing application  314  receives a request regarding bibliographic information issued from the multifunction peripheral  103 ,  104 , or  105 . 
     In step S 1003 , the remote hold printing application  314  determines whether the requested bibliographic information and user information can be extracted from the received request. If the information cannot be extracted, the processing advances to step S 1015 , an error is transmitted, and the processing ends. 
     In step S 1004 , the remote hold printing application  314  diverges the processing according to the type of the request regarding bibliographic information. If it is determined in step S 1004  that new registration (POST) of bibliographic information is requested, the processing advances to step S 1005  and the remote hold printing application  314  performs bibliographic information registration processing. 
     In step S 1005 , the remote hold printing application  314  determines whether bibliographic information that is to be newly registered is bibliographic information regarding an already registered user. If the bibliographic information to be newly registered is bibliographic information regarding an unregistered user, bibliographic information regarding the user is created in step S 1006 . 
     In step S 1007 , the remote hold printing application  314  newly registers the target bibliographic information. 
     If it is determined in step S 1004  that an update (PUT) of bibliographic information is requested, the processing advances to step S 1008  and the remote hold printing application  314  executes processing for updating the target bibliographic information. 
     In step S 1008 , the remote hold printing application  314  determines whether or not the bibliographic information to be updated exists. If the bibliographic information to be updated does not exist, an error is transmitted in step S 1015  and a series of processes ends. If the bibliographic information to be updated exists, the remote hold printing application  314  updates the target bibliographic information in step S 1009 . 
     If it is determined in step S 1004  that acquisition (GET) of bibliographic information is requested, the processing advances to step S 1010  and the remote hold printing application  314  executes processing for acquiring the target bibliographic information. 
     In step S 1010 , the remote hold printing application  314  determines whether or not a target user with respect to whom the bibliographic information is to be acquired exists. If the target user does not exist, an error is transmitted in step S 1015  and a series of processes ends. If the target user exists, the remote hold printing application  314  acquires a list of bibliographic information regarding the target user in step S 1011 . 
     If it is determined in step S 1004  that deletion (DELETE) of bibliographic information is requested, the processing advances to step S 1012  and the remote hold printing application  314  executes processing for deleting the target bibliographic information. 
     In step S 1012 , the remote hold printing application  314  determines whether or not the bibliographic information to be deleted exists. If the bibliographic information to be deleted does not exist, an error is transmitted in step S 1015  and a series of processes ends. If the bibliographic information to be deleted exists, the remote hold printing application  314  deletes the target bibliographic information in step S 1013 . 
     In step S 1014 , in response to each request, the remote hold printing application  314  transmits a processing result to the image forming apparatus that issued the request, and ends a series of processes. 
     Printing Procedure 
       FIG. 11  is a flow chart showing one exemplary procedure of print processing that is executed by the CPU  201  of the multifunction peripheral  105 , which is the output apparatus according to Embodiment 1, when the print start button  510  or  532  is pressed by the user with respect to a selected document. S 1101  to S 1113  denote steps. 
     First, in step S 1101 , the hold printing application  313  or the remote hold printing application  314  displays a document list ( FIG. 5A or 5B ) in the operation unit  206  of the multifunction peripheral  105 . 
     In step S 1102 , the hold printing application  313  or the remote hold printing application  314  receives, from the application platform  307 , selected document information that indicates print data selected by the user as a printing target from documents  506  and  507  or documents  526  to  529  in the displayed document list. 
     In step S 1103 , the hold printing application  313  or the remote hold printing application  314  reads bibliographic information regarding print data at the top of the received selected document information from the HDD  204 . 
     Steps S 1104  to S 1111  and S 1113  are repeatedly executed sequentially focusing on print jobs that are selected as printing targets. In step S 1104 , the hold printing application  313  or the remote hold printing application  314  extracts the storage location  645  and  646  of print data that is included in the bibliographic information. 
     In step S 1113 , the processing advances to step S 1107  if the hold printing application  313  is running as a result of the user having touched the print icon  401 . In contrast, in step S 1113 , the processing advances to step S 1105  if the remote hold printing application  314  is running as a result of the user having touched the remote print icon  402 . 
     In step S 1105 , the remote hold printing application  314  determines whether the print data is held by the self apparatus, which is the multifunction peripheral  105 , or another apparatus, based on the extracted storage location of the print data. The determination performed in step S 1105  is determination as to which of the self apparatus and another apparatus is holding the print data, and accordingly can be made depending on whether the IP address matches the IP address of the self apparatus, for example. If the print data is held by another apparatus, the processing advances to step S 1106 . 
     In step S 1106 , the remote hold printing application  314  requests, via the network I/F  210 , the document receiving apparatus  103  storing the print data to transmit the print data, and receives the print data from the document receiving apparatus  103 . 
     In step S 1107 , the hold printing application  313  or the remote hold printing application  314  acquires print data that is retained in the HDD  204  or the print data acquired from the document receiving apparatus  103  in step S 1106 . After the print data is acquired, print processing is performed through the application platform  307 . 
     In step S 1108 , the hold printing application  313  or the remote hold printing application  314  updates bibliographic information by setting a print finished flag to the bibliographic information regarding the printed print data, and stores the updated bibliographic information in the HDD  204 . 
     In step S 1109 , the hold printing application  313  or the remote hold printing application  314  transmits a bibliographic information update request to the bibliography server apparatus  104 . 
     In step S 1110 , the hold printing application  313  or the remote hold printing application  314  checks whether or not all print data for which a print instruction has been received was printed. 
     If there is unprinted print data, bibliographic information regarding the next print data is read in step S 1111  and the processes in step S 1104  and the following steps are repeated. 
     If it is confirmed in step S 1110  that all print data has been printed, the processing advances to step S 1112 , and the hold printing application  313  or the remote hold printing application  314  again displays a document list in which printed print data is not displayed, in the operation unit  206 . Thus, a series of print processes ends. 
       FIG. 12  is a flow chart showing processing that is executed by the CPU  201  of the multifunction peripheral  103 , which is the document receiving apparatus according to Embodiment 1, when a request regarding retained print data is received by the multifunction peripheral  103 . S 1201  to S 1206  denote steps. 
     First, in step S 1201 , the remote hold printing application  314  waits to receive a request regarding print data from the multifunction peripheral  104  or  105 . In step S 1202 , the remote hold printing application  314  receives a request regarding print data. Examples of requests received in this step include a print data transmission request that is transmitted from the multifunction peripheral  105 , which is the output apparatus, in step S 1106  in  FIG. 11 . In step S 1203 , the remote hold printing application  314  determines whether or not the request target print data can be extracted. If the print data cannot be extracted, that is, if the target print data is not stored in the HDD  204 , the processing advances to step S 1206 , and the remote hold printing application  314  transmits error information to the source of the request, and ends a series of processes. 
     If it is determined in step S 1203  that the print data can be extracted, the processing advances to step S 1204 , and the remote hold printing application  314  acquires the target print data by reading it from the HDD  204 . 
     In step S 1205 , the remote hold printing application  314  transmits a processing result regarding the acquired print data to the source of the request. If the request received in step S 1202  is a print data transmission request, the target print data is transmitted to the source of the request. Alternatively, if the received request is a print data deletion request, the target print data is deleted, and a notification of completion of the deletion is transmitted to the source of the request. Thus, a series of processes ends. 
     With the above-described configurations and procedures, the invention according to the present embodiment makes it possible to further provide a bibliography server in an image forming system that is constituted by image forming apparatuses, and unitarily manage bibliographic information regarding hold printing jobs that are stored in the image forming apparatuses, using the bibliography server. Accordingly, even when remote hold printing is performed using an output apparatus, a list of hold printing jobs that can be printing targets can be acquired by merely accessing the bibliography server, and the list of printing target jobs can be immediately presented to the user without causing the user to feel any stress. Accordingly, the effects become more noticeable as the number of image forming apparatuses that function as document receiving apparatuses connected to the image forming system increases. 
     Note that, in the present embodiment, the bibliography server is one of the image forming apparatuses connected to the image forming system, but a configuration is also possible in which a personal computer functions as the bibliography server, for example. 
     Embodiment 2 
     In Embodiment 1, an example is described in which hold printing and remote hold printing are dynamically switched, and bibliographic information stored in the self apparatus is used in the case of hold printing, and bibliographic information acquired from the bibliography server apparatus is used in the case of remote hold printing. 
     According to Embodiment 1, in the case of remote hold printing, a document list is displayed by acquiring bibliographic information from the bibliography server apparatus and storing the bibliographic information in the self apparatus, when displaying the list, and therefore display of the list may be delayed. Furthermore, there are cases in which bibliographic information that is acquired from the bibliography server apparatus and stored in the self apparatus overlaps with bibliographic information that is already stored in the self apparatus, and HDD resources are unnecessarily used. 
     Therefore, in Embodiment 2, an example will be described in which, in a method for managing bibliographic information in a multifunction peripheral that functions as an output apparatus, bibliographic information is acquired from a bibliography server when a user logs in to the output apparatus, and only bibliographic information regarding remote documents is stored in the output apparatus, as a node other than local documents. Note that remote documents mean print jobs or print data stored in other image forming apparatuses. 
     Major differences from Embodiment 1 are the saving configuration ( FIG. 13 ) of bibliographic information and the acquisition timing of bibliographic information (step S 1405  in  FIG. 14 ), and Embodiment 2 is the same as Embodiment 1 except these points. Therefore, a description of matter that is common between Embodiments 1 and 2 is omitted. 
     Saving Format of Bibliographic Information 
       FIG. 13  is a diagram showing one example of a saving format of bibliographic information stored in each multifunction peripheral. Bibliographic information  1301  shows the saving format of bibliographic information stored in the bibliography server apparatus  104 , and includes the user name  603  “Sato” as the head node and four pieces of bibliographic information that are respectively created in multifunction peripherals, transmitted to the bibliography server apparatus, and stored under the head node. 
     Bibliographic information  1302  and  1303  show the saving format of bibliographic information stored in the document receiving apparatus  103 . The bibliographic information  1302  includes the user name  623  “Sato” as the head node and bibliographic information regarding two pieces of print data input to the document receiving apparatus  103 , which is stored under the head node. The bibliographic information  1303  includes “Sato-remote” as the head node and bibliographic information regarding two pieces of print data, which is acquired from the bibliography server apparatus  104 . 
     Bibliographic information  1304  and  1305  show the saving format of bibliographic information stored in the document receiving apparatus/output apparatus  105 . The bibliographic information  1304  includes the user name  643  “Sato” as the head node and bibliographic information regarding two pieces of print data input to the document receiving apparatus/output apparatus  105 , which is stored under the head node. The bibliographic information  1305  includes “Sato-remote” as the head node and bibliographic information regarding two pieces of print data, which is acquired from the bibliography server apparatus  104 . 
     Document List Display Procedure 
       FIG. 14  is a flow chart showing one exemplary procedure of document list display processing that is executed by the CPU  201  of the multifunction peripheral  105 , which is the document receiving apparatus/output apparatus according to Embodiment 2. S 1401  to S 1414  denote steps. In the present embodiment, the procedure shown in  FIG. 14  is executed instead of the procedure shown in  FIG. 9  of Embodiment 1. 
     First, in step S 1401 , the authentication service  309  displays an authentication screen (not shown), and waits for authentication information to be input. Upon accepting input of authentication information from the user, the operation unit  206  transmits the authentication information to the authentication service  309  via the operation unit I/F  205  (step S 1402 ). 
     In step S 1402 , the authentication service  309  performs user authentication. In step S 1403 , it is determined whether or not the authentication was successful, and if it is determined that the authentication was successful, the authentication service  309  notifies each application  312  of the authentication result, and processes in step S 1404  and the following steps are performed. If it is determined in step S 1403  that the authentication was not successful, the processing returns to the process performed in step S 1401 . 
     In step S 1404 , after the authentication having been successfully performed, the remote hold printing application  314  connects to the bibliography server apparatus  104  via a network using authenticated user information, before display of a document list is requested. 
     Steps S 1405  to S 1408  are repeatedly executed focusing on each print job of the logged in user (authenticated user), which is acquired from the bibliography server apparatus  104 . In step S 1405 , the remote hold printing application  314  requests bibliographic information regarding print jobs of the authenticated user from the connected bibliography server apparatus  104 , and acquires the bibliographic information from the bibliography server apparatus  104 . For example, if the user name of the logged in user is “Sato”, bibliographic information associated with the user name  603  “Sato” is acquired out of the bibliographic information shown in  FIGS. 6A to 6C . 
     In step S 1406 , the remote hold printing application  314  acquires information regarding the IP address  605 , which is information regarding the storage location of print data, from a piece of bibliographic information out of the acquired bibliographic information. 
     In step S 1407 , the remote hold printing application  314  compares the IP address  605  indicating the storage location of the print data with the IP address of the multifunction peripheral  105  functioning as the output apparatus, which is the self apparatus, and determines whether or not the IP addresses match. If the IP addresses do not match, the processing advances to step S 1408 . If the IP addresses match, the processing advances to step S 1405  to perform the same processing on all other pieces of bibliographic information. 
     In step S 1408 , the remote hold printing application  314  stores the bibliographic information for which the IP address  605  indicating the storage location of the print data does not match with the IP address of the self apparatus, that is, bibliographic information regarding a remote document, using “Sato-remote”  601  as the head node. Through this processing, bibliographic information regarding local documents is stored and managed under the node “Sato”, and bibliographic information regarding remote documents is stored and managed under the node “Sato-remote”, without duplication of bibliographic information. After bibliographic information regarding print jobs of the logged in user has been acquired through the processes performed in steps S 1405  to S 1408 , step S 1409  is executed. 
     In step S 1409 , the hold printing application  313  or the remote hold printing application  314  is activated as a result of the print application icon  401  or  402  being touched by the user. 
     In step S 1410 , the hold printing application  313  or the remote hold printing application  314  displays the document list screen  500  or  520 . 
     In step S 1411 , the processing advances to step S 1412  if the hold printing application  313  has been activated, or the processing advances to step S 1413  if the remote hold printing application  314  has been activated. 
     In step S 1412 , the hold printing application  313  acquires bibliographic information stored under the user name “Sato”, which is the head node. 
     In step S 1413 , the remote hold printing application  314  acquires bibliographic information stored under the user name “Sato”, which is the head node, and bibliographic information stored under the user name “Sato-remote”, which is the head node. 
     In step S 1414 , the hold printing application  313  or the remote hold printing application  314  displays a list (document list) of print data that can be printing targets and deletion targets in the operation unit  206 , based on the acquired bibliographic information, and then ends a series of processes 
     According to the present embodiment described above, when the user logs in, bibliographic information regarding print jobs of the user is acquired from the bibliography server, and therefore, when the remote hold printing application is executed, a list of bibliographic information regarding print jobs that can be printing targets can be displayed without delay. 
     OTHER EMBODIMENTS 
     Embodiment(s) of the present invention can also be realized by a computer of a system or apparatus that reads out and executes computer executable instructions (e.g., one or more programs) recorded on a storage medium (which may also be referred to more fully as 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 invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions. 
     This application claims the benefit of Japanese Patent Application No. 2019-037775, filed Mar. 1, 2019, which is hereby incorporated by reference herein in its entirety.