Abstract:
A push-type pull printing system comprising a server and an image forming apparatus, the server sending, to the image forming apparatus, a print job including print data and a print condition instruction command for the print data, and the image forming apparatus executing a print process based on the print job. Here, the image forming apparatus comprises an input receiver operable to receive an input of a print condition, a converter operable to convert the inputted print condition, before being transmitted to the server, to an instruction command in a description language interpretable by the image forming apparatus, and a transmitter operable to transmit the converted instruction command to the server; and the server comprises a job transmitter operable to receive the converted instruction command from and send the print job to the image forming apparatus, the print job including the instruction command as the print condition instruction command.

Description:
[0001]    This application is based on application No. 2007-049856 filed in Japan, the content of which is hereby incorporated by reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    (1) Field of the Invention 
         [0003]    This invention relates to a push-type pull printing system, in particular to a technology for controlling a content of a print process by issuing a print job. 
         [0004]    (2) Description of the Related Art 
         [0005]    In recent years, a pull printing system has come into use. The pull printing system includes an image forming apparatus called MFP (Multi-Function Peripheral) performing versatile functions such as copying, printing, and faxing, and a server providing print data for the image forming apparatus via a network such as a LAN. 
         [0006]    There are two types of pull printing systems: a pull-type and push-type. In the pull-type, a print process is executed by sequentially performing the following sub processes: (a) the image forming apparatus issues a print job acquisition request to the server, (b) the server issues a print job to the image forming apparatus, and (c) the image forming apparatus acquires print data from a storage location specified by the print job issued by the server. On the other hand, in the push-type, a print process is executed by sequentially performing the following sub processes: (a) the image forming apparatus gives an instruction on print data and a print condition for the print data to the server, (b) the server issues a print job, based on the instruction, including the print data and an instruction command of the print condition for the print data, (c) the image forming apparatus receives the print job issued by the server. 
         [0007]      FIG. 14  is an image diagram showing a flow of the print process of the push-type pull printing system. 
         [0008]    A reference numeral  50  in  FIG. 14  indicates an image forming apparatus,  60  indicates a server, and  500  indicates a first print instruction information. 
         [0009]    The first print instruction information  500  includes print data specification information  501  and print setting information  502 , and is transmitted to the server  60  from the image forming apparatus  50  to give an instruction on a print target file and a print condition. 
         [0010]    The print data specification information  501  includes a file name of the print target file requested to be printed and identification information of the image forming apparatus  50 . 
         [0011]    The print setting information  502  is information which indicates instructions relating to the print condition input by a user using the image forming apparatus  50 . The instructions are such as a number of copies, specification of a sheet feeder, post-print process (stapling, punching, etc.), and print format (double-sided printing, single-sided printing, etc.). 
         [0012]    A numeral reference  600  in  FIG. 14  indicates a print job. 
         [0013]    The print job  600  is issued by the server  60  in order to make the image forming apparatus  50  execute the print process, and includes first PJL (Printer Job Language) description print setting information  602 , PJL description print management information  601 , and PDL (Page Description Language) description print data  603 . 
         [0014]    Here, note that the PDL is a language for describing information regarding a page description, a drawing and the like for printing, and includes Post Script by Adobe Systems Incorporated, PCL (Page Control Language) by Hewlett Packard Company (US), RPCS (Refined Printing Command Stream) by Ricoh Co., Ltd. 
         [0015]    Also, the PJL is a language developed by Hewlett Packard Company (US) for controlling a print device. 
         [0016]    The server  60  creates the first PJL description print setting information  602  by converting the description language of the print setting information  502  into PJL commands which are interpretable for the print device of the image forming apparatus  50 . 
         [0017]    The PJL description print management information  601  is information which is created by the server  60  to manage print jobs and described in the PJL. Specifically, an identifier of the print job and identification information of the image forming apparatus to which the print job is outputted are included in this information. 
         [0018]    The PDL description print data  603  indicates data content of the print target file. The server  60  creates the PDL description print data  603  by converting the data format of the print target file into a PDL data format which is interpretable for the print device of the image forming apparatus  50 . 
         [0019]    In the above-mentioned push-type pull printing system, the printing is performed by taking following steps: (1) the first print instruction information  500  is transmitted from the image forming apparatus  50  to the server  60 , (2) the server  60  issues the print job  600  upon converting description languages of the data of the print target file and an instruction of the print condition thereof into description languages (PJL, PDL), which are interpretable for the print device of the image forming apparatus  50 , and (3) the image forming apparatus  50  executes a print process  700  in accordance with the issued print job  600 . 
         [0020]    As mentioned above, in the push-type pull printing system, the print job is issued by the server upon converting the description languages of the print job into languages which are interpretable for the print device of the image forming apparatus. Consequently, even in a case where an image forming apparatus of a different type or manufacturer is used, it is not necessary to install multiple interpreters to each image forming apparatus according to the type of the data format of the print target file which has been converted into the PDL. Thus, the print process can be executed easily based on the print job transmitted from the server. 
         [0021]    Moreover, when a trouble occurs in the print process, the server can reissue the print job, allowing easy reprinting. 
         [0022]    Also, the print process can be executed using an ordinary printing protocol (e.g. LPR (Line Printer Daemon Protocol)), thus reducing a workload of controlling communication at the image forming apparatus side. 
         [0023]    However, because PJL data is of a relatively simple ASCII (American Standard Code for Information Interchange) format, a considerable number of manufacturers have created unique commands, using these additional commands as execution commands for various printing functions. As a result, every time an image forming apparatus using uniquely-created PJL commands is newly added to a push-type pull printing system, the uniquely created additional PJL commands corresponding to an instruction of a new print condition need to be newly registered to the server. Otherwise, it is likely to have trouble in a conversion process of the description language of the instruction of the print condition when issuing the print job. Accordingly, the print job issuing function of the server requires additional maintenance effort. 
         [0024]    Further, when the additional registration of the PJL commands is omitted, part of the print function instructed by the print condition set at the image forming apparatus may not be executed. 
       SUMMARY OF THE INVENTION 
       [0025]    The present invention was conceived in view of the above problems, and aims to provide a push-type pull printing system, a pull printing method, and an image forming apparatus which enable an easy maintenance of the print job issuing function and proper execution of the instruction of the print condition set at the image forming apparatus even if an image forming apparatus is newly added to the push-type pull printing system. 
         [0026]    In order to achieve the above object, the present invention provides a push-type pull printing system comprising a server and an image forming apparatus, the server sending, to the image forming apparatus, a print job including print data and a print condition instruction command for the print data, and the image forming apparatus executing a print process based on the print job, the image forming apparatus comprising: an input receiver operable to receive an input of a print condition; a converter operable to convert the inputted print condition, before being transmitted to the server, to an instruction command whose description language is interpretable by the image forming apparatus; and a transmitter operable to transmit the converted instruction command to the server, and the server comprising: a job transmitter operable to receive, from the image forming apparatus, the converted instruction command, and to send, to the image forming apparatus, the print job including therein the received converted instruction command as the print condition instruction command. 
         [0027]    The present invention also provides an image forming apparatus in a push-type pull printing system, executing a print process based on a print job that is sent by a server and includes print data and a print condition instruction command for the print data, the image forming apparatus comprising: an input receiver operable to receive an input of the print condition; a converter operable to convert the inputted print condition, before being transmitted to the server, to an instruction command whose description language is interpretable by the image forming apparatus; and a transmitter operable to transmit the converted instruction command to the server. 
         [0028]    In each of the above configuration, a description language of the print condition instruction command may be a printer job language (PJL) and a description language of the print data may be a page description language (PDL). 
         [0029]    The present invention also provides a pull printing method used in a push-type pull printing system comprising a server and an image forming apparatus, the server sending, to the image forming apparatus, a print job including print data and a print condition instruction command for the print data, and the image forming apparatus executing a print process based on the print job, the pull printing method comprising the steps of: causing the image forming apparatus to i) receive an input of the print condition, ii) convert the inputted print condition, before being transmitted to the server, to an instruction command whose description language is interpretable by the image forming apparatus, and iii) transmit the converted instruction command to the server; and causing the server to receive, from the image forming apparatus, the converted instruction command, and to send, to the image forming apparatus, the print job including therein the received converted instruction command as the print condition instruction command. 
         [0030]    In the present invention with the above configuration, the server side does not need to perform a conversion process to convert the instruction of the print condition to the instruction command interpretable by the image forming apparatus. Thus, in a case where an image forming apparatus including an instruction uniquely set by a manufacturer in order for the image forming apparatus to execute a particular print condition is newly added to a push-type pull printing system, an instruction command for the image forming apparatus to execute the particular print condition, which corresponds to the instruction of the particular print condition, does not need to be additionally registered to the server side. This allows an easy maintenance of the print job issuing function on the server side, and, at the same time, ensures smooth execution of the print condition by the image forming apparatus even when the print condition includes use of the uniquely-set command. 
         [0031]    Here, in the above configuration, the following may be implemented. The inputted print condition includes user authentication information, the user authentication information is encrypted before being converted to the instruction command and transmitted to the server, and the image forming apparatus further comprises: a decrypter operable to acquire the encrypted user authentication information by interpreting the print job and decrypt the acquired encrypted user authentication information; a verifier operable to perform a verification of the decrypted user authentication information; and a printer operable to execute the print process if the verification is successful. 
         [0032]    Consequently, even when the push-type pull printing system includes an image forming apparatus having an authentication print function that requires authentication of a user before executing a print process, the user authentication information encrypted by the image forming apparatus is converted to a description language interpretable by the image forming apparatus, and the converted user authentication information can be directly included in the print job issued by the server without change. Thus, the server side can execute the authentication print function without performing additional processes for encrypting and decrypting the user authentication information. Also, since the user authentication information has been encrypted when being transmitted to/from the server, a leakage of the user authentication information can be prevented. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0033]    These and other objects, advantages and features of the invention will become apparent from the following description thereof taken in conjunction with the accompanying drawings which illustrate specific embodiments of the invention. In the drawings: 
           [0034]      FIG. 1  shows a structure of a push-type pull printing system  100 ; 
           [0035]      FIG. 2  is a functional block diagram showing a function structure of an image forming apparatus  101 ; 
           [0036]      FIG. 3  is a functional block diagram showing a function structure of a print device  120 ; 
           [0037]      FIG. 4  is a functional block diagram showing a function structure of a server  104 ; 
           [0038]      FIG. 5  shows a specific example of a print data specification screen; 
           [0039]      FIG. 6  shows a specific example of a print condition setting screen; 
           [0040]      FIG. 7  shows a specific example of second PJL description print setting information; 
           [0041]      FIG. 8  shows a specific example of second print instruction information; 
           [0042]      FIG. 9  shows a specific example of a print job generated by a print job generator  141 ; 
           [0043]      FIG. 10  is an image diagram showing an overall process of a print process performed in the push-type pull printing system  100 ; 
           [0044]      FIG. 11  is a flowchart showing a transmission process of the second print instruction information performed by the image forming apparatus  101 ; 
           [0045]      FIG. 12  is a flowchart showing a print controlling process performed by the image forming apparatus  101 ; 
           [0046]      FIG. 13  is a flowchart showing a print job issuing process performed by the server  104 ; and 
           [0047]      FIG. 14  is an image diagram showing a print process in a push-type pull printing system. 
       
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0048]    Although the present invention has been fully described by way of examples with reference to the accompanying drawings, it is to be noted that various changes and modifications will be apparent to those skilled in the art. Therefore, unless otherwise such changes and modifications depart from the scope of the present invention, they should be construed as being included therein. 
         [0049]    The best modes for implementing the present invention are described next with reference to drawings. 
       &lt;Structure&gt; 
       [0050]    (Push-Type Pull Printing System  100 ) 
         [0051]      FIG. 1  shows a structure of a push-type pull printing system  100 . 
         [0052]    The push-type pull printing system  100  includes image forming apparatuses  101  to  103  and a server  104 . 
         [0053]    Each image forming apparatus and the server  104  are connected to each other by a LAN (Local Area Network)  105 . 
         [0054]    Also, each image forming apparatus is connected to a communication network  106  constituted of a telephone line and the like to construct a network such that the image forming apparatus can fax via the communication network  106 . 
         [0055]    (Image Forming Apparatuses  101 ,  102 ,  103 ) 
         [0056]    (Hardware Structure) 
         [0057]    The image forming apparatuses  101 ,  102  and  103  of the present embodiment include a microprocessor, a ROM, a RAM, a hard disk unit, an operation panel (a touch panel or a panel including multiple keys for input, a liquid crystal display and the like), a scanner, a printer including an image printer such as a laser printer, a facsimile and the like. A computer program is stored in the above-mentioned RAM or hard disk unit. The image forming apparatuses  101  to  103  achieve respective functions, which will be described in the following function structure, as a result of the microprocessor operating in accordance with the computer program. Here, the computer program is made of a combination of multiple command codes giving instructions to the computer in order to achieve a predetermined function. 
         [0058]    (Function Structure) 
         [0059]    The image forming apparatuses  101 ,  102 , and  103  have resembling function structures. Therefore, the function structure of the image forming apparatus  101  will be described as an example in the following. 
         [0060]      FIG. 2  is a functional block diagram showing a function structure of an image forming apparatus  101 . As shown in  FIG. 2 , the image forming apparatus  101  includes a communication controller  110 , a capability information storage  111 , a registration authentication information storage  112 , an image reader  113 , a modem  114 , a FAX communication controller  115 , a network controller  116 , an operation panel part  117 , a print command generator  118 , a central controller  119 , and a print device  120 . 
         [0061]    (Communication Controller  110 ) 
         [0062]    The communication controller  110  is an interface used for connecting to the LAN  105 , and controls the communication with the image forming apparatuses  102  and  103  and the server  104  connected to the LAN  105 . The above-mentioned communication control is performed using a predetermined protocol such as TCP (Transmission Control Protocol)/IP (Internet Protocol), LPR, RAW, IPP (Internet Printing Protocol). 
         [0063]    (Capability Information Storage  111 ) 
         [0064]    The capability information storage  111  stores identification information of the image forming apparatus  101 , a PDL data format interpretable at the image forming apparatus  101 , and information regarding a printing protocol applicable to the image forming apparatus  101 . 
         [0065]    (Registration Authentication Information Storage  112 ) 
         [0066]    The registration authentication information storage  112  stores registration authentication information of each user pre-registered as an authorized user of the image forming apparatus  101  and an encryption key of a common key system for encrypting and decrypting user authentication information, which will be described later. 
         [0067]    It should be noted here that the “registration authentication information” is composed of a user ID of the above-mentioned each authorized user and a password. 
         [0068]    (Image Reader  113 ) 
         [0069]    The image reader  113  includes an image input device such as a scanner, and, with a built-in light source, irradiates light on an image of letters, a drawing, table or photo recorded on a paper document. The image reader  113  forms a reflected image on a solid-state sensing device using a lens and converts the formed image into an image signal via the solid-state sensing device, generating image data as a result. 
         [0070]    (Modem  114 ) 
         [0071]    The Modem  114  is used to modulate transmitting signals transmitted to and demodulate receiving signals received from an outside image forming apparatus, a communication counterpart, via the communication network  106 . 
         [0072]    (FAX Communication Controller  115 ) 
         [0073]    The FAX communication controller  115 , via the modem  114 , modulates transmitting signals transmitted to and demodulates receiving signals received from an image forming apparatus, a communication counterpart. 
         [0074]    Also, the Fax communication controller  115  is connected to the communication network  106  via the network controller  116  and communicates with an image forming apparatus, a communication counterpart. 
         [0075]    (Network Controller  116 ) 
         [0076]    The network controller  116  is used to connect to the communication network  106 . 
         [0077]    (Operation Panel Part  117 ) 
         [0078]    The operation panel part  117  includes multiple input keys and a display part (e.g. liquid crystal display)  1171  in  FIG. 1 , and a touch panel is mounted on a surface of the display part  1171 . After the user inputs an instruction by touch input from the touch panel or by key input from the input keys, the operation panel part  117  notifies the central controller  119  of the inputted instruction. 
         [0079]    The operation panel part  117  displays a GUI (Graphic User Interface) display screen (hereinafter, referred to as “print data specification screen”) on the display part  1171  to receive a specification of the print data. The display of the GUI display screen is based on file list information which has been acquired from the server  104  and shows a correspondence of file names and directory names of the print target files. 
         [0080]      FIG. 5  shows a specific example of a print data specification screen. In  FIG. 5 , files  1  to  50  are displayed as print target files along with the directory names, and the print data specification screen indicates that the file  2  enclosed in a rectangular box has been specified. 
         [0081]    Also, the operation panel part  117 , during a second instruction information transmitting process which will be described later, displays a GUI display screen (hereinafter, referred to as “print condition setting screen”) on a display part  1171  to receive a print-condition setting input. 
         [0082]      FIG. 6  shows a specific example of a print condition setting screen. The print condition in  FIG. 6  indicates settings such as a user name, a number of copies, a paper feed tray, a print format, and user authentication information composed of a user ID and a password. 
         [0083]    (Print Command Generator  118 ) 
         [0084]    The print command generator  118  converts a description language of the input or default print setting information inputted from the central controller  119  into PJL commands, thereby generating the second PJL description print setting information, and outputs it to the central controller  119 . 
         [0085]      FIG. 7  shows a specific example of second PJL description print setting information. The second PJL description print setting information shown in  FIG. 7  has been generated by converting, into the PJL commands, the description language of the input print setting information set on the print condition setting screen in  FIG. 6 . For example, “@PJL SET USERNAME=“User 1”” is a PJL command converted from a setting “USER NAME: User 1” in  FIG. 6 . Likewise, “@PJL SET QTY=5” is a PJL command converted from a setting “NUMBER OF COPY: 5” in  FIG. 6 . 
         [0086]    (Central Controller  119 ) 
         [0087]    The central controller  119  performs an overall control on the image forming apparatus  101 , a generation process of the second print instruction information, an acquisition process of a print job, and an acquisition process of registration authentication information. 
         [0088]    (Generation Process of Second Print Instruction Information) 
         [0089]    After a user specifies a print target file name via the print data specification screen, the central controller  119  acquires identification information of the image forming apparatus  101  from the capability information storage  111  and generates print data specification information including the acquired identification information and the name of the specified print target file. 
         [0090]    Next, after the user completes an input for setting the print condition from the print condition setting screen, the central controller  119  outputs to the print command generator  118  the information indicating the print condition specified by the user input (hereinafter, referred to as “input print setting information”). The print command generator  118  converts the description language of the input print setting information into the PJL commands, thus generating the second PJL description print setting information. 
         [0091]    Note that in a case where there is no setting input made on the above-mentioned print condition setting screen, the central controller  119  outputs to the print command generator  118  information indicating the preset default print condition (hereinafter, referred to as “default print setting information”), and the print command generator  118  converts the description language of the default print setting information to the PJL commands to generate the second PJL description print setting information. 
         [0092]    Also, when the input of user authentication information is included in the print condition, the central controller  119  encrypts the user authentication information using an encryption key stored in the registration authentication information storage  112  and outputs the encrypted user authentication information to the print command generator  118 . 
         [0093]    Next, after the second PJL description print setting information is inputted from the print command generator  118 , the central controller  119  generates the second print instruction information including the generated print data specification information and the input second PJL description print setting information, and transmits the generated second print instruction information to the server  104  via the communication controller  110 . 
         [0094]      FIG. 8  shows a specific example of second print instruction information. 
         [0095]    (Print Job Acquisition Process) 
         [0096]    After the print job issued by the server  104  is received by the communication controller  110 , the central controller  119  acquires the received print job from the communication controller  110  and outputs the acquired print job to the print device  120 . 
         [0097]    Here, the “print job” includes the same information as the print job  600  described in the Background Art section, except that the second PJL description print setting information is included therein instead of the first PJL description print setting information. 
         [0098]    (Registration Authentication Information Acquisition Process) 
         [0099]    The central controller  119  acquires, from the registration authentication information storage  112 , registration authentication information of the corresponding user ID and an encryption key in response to a request from the print device  120  and outputs them to the print device  120 . 
         [0100]    (Print Device  120 ) 
         [0101]      FIG. 3  is a functional block diagram showing a function structure of a print device  120 . 
         [0102]    The print device  120  includes a print command interpreter  121 , an authentication part  122 , and a print controller  123 . 
         [0103]    (Print Command Interpreter  121 ) 
         [0104]    The print command interpreter  121  includes a PDL interpreter  1211  and a PJL interpreter  1212 . 
         [0105]    ((PDL Interpreter  1211 )) 
         [0106]    The PDL interpreter  1211  acquires PDL description print data from the print job inputted from the central controller  119 , interprets the acquired data using an interpreter for the PDL, and outputs the interpretation result to the authentication part  122 . 
         [0107]    It should be noted here that the PDL description print data includes the same information as the PDL description print data  603  described in the Background Art section, and is created by the server  104  converting the data format of the print target file into a PDL data format which is interpretable for the print device of the image forming apparatus  101 . 
         [0108]    ((PJL Interpreter  1212 )) 
         [0109]    The PJL interpreter  1212  acquires the PJL description print management information and the second PJL description print setting information from the print job inputted from the central controller  119 , interprets the acquired information using an interpreter for the PJL, and outputs the interpretation result to the authentication part  122 . 
         [0110]    (Authentication Part  122 ) 
         [0111]    The authentication part  122  acquires the encrypted user authentication information based on the interpretation result of the second PJL description print setting information inputted from the PJL interpreter  1212 , and decrypts the acquired user authentication information with use of the encryption key stored in the registration authentication information storage  112 . 
         [0112]    Furthermore, the authentication part  122  acquires each registration authentication information corresponding to the user ID, which is stored in the registration authentication information storage  112  via the central controller  119  and performs an authentication process of the user authentication information by verifying the decrypted user authentication information against the acquired registration authentication information. 
         [0113]    During the above authentication process, i) if the verification succeeds, the authentication part  122  outputs to the print controller  123  the interpreted result inputted from the print command interpreter  121 , and ii) if the verification fails, the execution of the print process is terminated without outputting the interpreted result to the print controller  123 . 
         [0114]    (Print Controller  123 ) 
         [0115]    After the interpreted result is inputted from the authentication part  122 , the print controller  123  rasterizes the print data interpreted by the PDL interpreter  1211  and performs a print process to print an image on recording paper based on the rasterized image data in accordance with the print condition interpreted by the PJL interpreter  1212 . 
         [0116]    (Server  104 ) 
         [0117]    (Hardware Configuration) 
         [0118]    The server  104  of the present embodiment includes a microprocessor, a ROM, a RAM, a hard disk unit, a keyboard for inputting instructions, a mouse, a display unit composed of a liquid crystal display, a CRT, etc. and the like. A computer program is stored in the RAM or hard disk unit. The server  104  achieves each function mentioned in the following descriptions of function structures as a result of the microprocessor operating in accordance with the computer program. 
         [0119]      5 (Function Structure) 
         [0120]      FIG. 4  is a functional block diagram showing a function structure of a server  104 . 
         [0121]    The server  104  includes a communication controller  140 , a print job generator  141 , an apparatus information storage  142 , a print file storage  143 , and a controller  144 . 
         [0122]    (Communication Controller  140 ) 
         [0123]    The communication controller  140  is an interface used to connect to the LAN  105 , and controls communication between the server  104  and the image forming apparatuses  101 ,  102 , and  103  connected to the LAN  105 . The above-mentioned communication control is performed using a predetermined protocol such as TCP/IP, LPR, RAW, or IPP. 
         [0124]    (Apparatus Information Storage  142 ) 
         [0125]    The apparatus information storage  142  stores information relating to network addresses of the respective image forming apparatuses (image forming apparatuses  101  to  103 ) in the push-type pull printing system  100 , PDL data formats which are interpretable by the respective image forming apparatuses, and the printing protocols which are applicable to the respective image forming apparatuses. 
         [0126]    (Print File Storage  143 ) 
         [0127]    The print file storage  143  stores multiple print target files and file list information indicating correspondence between file names and directory names of the print target files. 
         [0128]    (Controller  144 ) 
         [0129]    The controller  144  includes an operation panel display controller  1441 , an apparatus information controller  1442 , a print job issuing controller  1443 , and a print file controller  1444 . 
         [0130]    (Operation Panel Display Controller  1441 ) 
         [0131]    The operation panel display controller  1441  reads out the file list information stored in the print file storage  143  in response to an acquisition request therefor from the image forming apparatus  101 . The operation panel display controller  1441  then transmits the read-out file list information to the image forming apparatus  101  via the communication controller  140 . 
         [0132]    (Apparatus Information Controller  1442 ) 
         [0133]    The apparatus information controller  1442  communicates with respective image forming apparatuses connected to LAN  105  via the communication controller  140 , acquires information stored in the capability information storage  111  from the respective image forming apparatuses, and stores the acquired information in the apparatus information storage  142 . The above process is performed periodically, updating the information. 
         [0134]    (Print Job Issuing Controller  1443 ) 
         [0135]    After receiving the second print instruction information transmitted from an image forming apparatus (e.g. image forming apparatus  101 ) connected to the LAN  105  via the communication controller  140 , the print job issuing controller  1443  acquires the second PJL description print setting information and the print data specification information from the received second print instruction information. The print job issuing controller  1443  then notifies the print file controller  1444  of the name of the print target file indicated by the print data specification information and acquires the print target file corresponding to the name of the print target file from the print file controller  1444 . After that, the print job issuing controller  1443  notifies the apparatus information controller  1442  of the identification information of the image forming apparatus indicated by the print data specification information and acquires, from the apparatus information controller  1442 , information regarding a PDL data format (hereinafter, referred to as “PDL data format information”) interpretable by the image forming apparatus. 
         [0136]    Next, the print job issuing controller  1443  creates an identification number for the print job and generates print management information including the identification number of the print job and the identification number of the image forming apparatus indicated by the print data specification information. 
         [0137]    The print job issuing controller  1443  then requests a generation of a print job at the print job generator  141  by outputting thereto the acquired second PJL description print setting information, print target file, and PDL data format information and the generated print management information. Following that, the print job issuing controller  1443  acquires the generated print job from the print job generator  141  and transmits the print job, via the communication controller  140 , to the image forming apparatus (here, the image forming apparatus  101 ) which is the transmission source of the second print instruction information. 
         [0138]    Also, the print job issuing controller  1443  temporarily retains the acquired print job and deletes the aforementioned print job upon receiving a notification of completion of the print job, transmitted, via the communication controller  140 , from the image forming apparatus (here, image forming apparatus  101 ) to which the print job has been transmitted. 
         [0139]    (Print File Controller  1444 ) 
         [0140]    The print file controller  1444  manages recording/reading-out of the print target file into/from the print file storage  143 . The recording of the-print target file is performed, for example, by the print file controller  1444  receiving the print target file transmitted from a PC (Personal Computer, not shown) connected to the LAN  105  via the communication controller  140  and storing the print target file into the print file storage  143 . 
         [0141]    Also, the reading out of the print target file is performed in response to a request from the print job issuing controller  1443 . 
         [0142]    (Print Job Generator  141 ) 
         [0143]    The print job generator  141  has a plurality of printer drivers corresponding to the data formats indicated by the PDL data format information of the respective image forming apparatuses connected to the LAN  105 , and performs a print data format conversion process, a print management information data format conversion process, and a print job generating process. 
         [0144]    (Print Data Format Conversion Process) 
         [0145]    Upon receiving an input of the print target file and the PDL data format information of the image forming apparatus (here, image forming apparatus  101 ), for which a print job is to be issued, from the print job issuing controller  1443 , the print job generator  141  uses a printer driver corresponding to the data format indicated by the PDL data format information to convert the data format of the inputted print target file and generates PDL description print data. 
         [0146]    (Print Management Information Data Format Conversion Process) 
         [0147]    The print job generator  141  converts the description language of the print management information inputted from the print job issuing controller  1443  into PJL, generating the PJL description print management information. 
         [0148]    (Print Job Generation Process) 
         [0149]    The print job generator  141  generates a print job from the PDL description print data generated by the print data format conversion process, the PJL description print management information generated by the print management information data format conversion process, and the second PJL description print setting information transmitted from the image forming apparatus (here, image forming apparatus  101 ) and then inputted from the print job issuing controller  1443 . 
         [0150]      FIG. 9  shows a specific example of a print job generated by a print job generator  141 . 
       &lt;Operation&gt; 
       [0151]    (Second Print Instruction Information Transmission Process) 
         [0152]      FIG. 11  is a flowchart showing a transmission process of the second print instruction information performed by the image forming apparatus  101 . 
         [0153]    Described next is the above-mentioned operation with reference to  FIG. 11 . Note that the image forming apparatuses  102  and  103  operate in a similar way to the image forming apparatus  101 . 
         [0154]    An execution instruction of the second print instruction information transmission process inputted by a user via the operation panel part  117  triggers the central controller  119  to start up a computer program related to the process (step S 1511 ), acquire file list information from the server  104  via the communication controller  110 , and display the print data specification screen on the display part  1171  of the operation panel part  117  based on the file list information (step S 1512 ). 
         [0155]    Next, after the print target file name is specified by the user via the displayed print data specification screen (step S 1513 ), the central controller  119  i) acquires identification information of the image forming apparatus  101  from the capability information storage  111 , ii) generates the print data specification information including the acquired identification information and the specified print target file name, iii) saves the print data specification information (step S 1514 ), iv) makes the operation panel part  117  display the print condition setting screen (step S 1515 ), and v) monitors whether or not the user has inputted a setting in the print condition setting screen (step S 1516 ). 
         [0156]    In the step S 1516 , i) if a setting has been inputted (step S 1516 : Y), the central controller  119  saves the input print setting information (step S 1517 ), and ii) if the setting has not been inputted, the central controller  119  saves the default print setting information (step S 1518 ). 
         [0157]    Next, after the user has inputted a print execution instruction via the operation panel part  117  (step S 1519 ), the central controller  119  outputs to the print command generator  118  the saved input or default print setting information. 
         [0158]    Having received the above input, the print command generator  118  converts the description language of the input or default print setting information into PJL commands (step S 1520 ), generating the second PJL description print setting information, and outputs it to the central controller  119 . 
         [0159]    Then the central controller  119  generates the second print instruction information including the second PJL description print setting information inputted from the print command generator  118  and the saved print data specification information, and transmits the generated second print instruction information to the server  104  via the communication controller  110  (step S 1521 ). 
         [0160]    (Print Control Process) 
         [0161]    In the following, a description will be made on the operation of the print control process by the image forming apparatus  101 .  FIG. 12  is a flowchart showing a print controlling process performed by the image forming apparatus  101 . 
         [0162]    Below is a description on the above-mentioned operation with reference to  FIG. 12 . Note that the image forming apparatuses  102  and  103  operate in a similar way to the image forming apparatus  101 . 
         [0163]    The central controller  119  receives the print job transmitted from the server  104  via the communication controller  110  (step S 1601 ) and outputs the received print job to the print device  120 . 
         [0164]    The print device  120  interprets the PDL description print data in the print job inputted from the central controller  119  at the PDL interpreter  1211  and interprets the PJL description print management information and the second PJL description print setting information in the print job at the PJL interpreter  1212  (step S 1602 ). Then the print device  120  acquires the user authentication information by decrypting the encrypted user authentication information with use of the encryption key stored in the registration authentication information storage  112  (step S 1603 ) and performs an authentication process at the authentication part  122  (step S 1604 ). In the authentication process, if the verification of the user authentication information against the corresponding registration authentication information succeeds (step S 1605 : Y), the print device  120  performs a print process at the print controller  123  performs (step S 1606 ) and notifies the central controller  119  of the completion of the print job and the identification number of the completed print job. 
         [0165]    Upon receiving the above-mentioned respective notifications from the print device  120 , the central controller  119  notifies the server  104  of the identification number of the completed print job via the communication controller  110  (step S 1607 ). 
         [0166]    If the verification fails in the step S 1605 , the print device  120  notifies the central controller  119  of the completion of the print job and the identification number of the completed print job and proceeds to the step S 1607 . 
         [0167]    Upon receiving the above-mentioned completion notification, the server  104  deletes the record of the issued print job. 
         [0168]    (Print Job Issuing Process) 
         [0169]    Described next is an operation of the print job issuing process by the server  104 .  FIG. 13  is a flowchart showing a print job issuing process performed by the server  104 . In the following, the above-mentioned operation is described with reference to  FIG. 13 . 
         [0170]    Having received the second print instruction information transmitted from the image forming apparatus (here, image forming apparatus  101 ) connected to the LAN  105 , the controller  144  i) acquires the second PJL description print setting information and the print data specification information from the second print instruction information (step S 1701 ), ii) acquires, from the print file storage  143 , the print target file corresponding to the print target file name indicated by the print data specification information (step S 1702 ), and iii) acquires, from the apparatus information storage  142 , the PDL data format information of the image forming apparatus (here, image forming apparatus  101 ) specified by the identification information of the image forming apparatus indicated by the print data specification information (step S 1703 ). 
         [0171]    After that, the controller  144  i) generates the identification number of the print job and the print management information including the generated identification number of the print job and the identification information of the image forming apparatus indicated by the print data specification information (step S 1704 ) and ii) outputs to the print job generator  141  the second PJL description print setting information acquired from the second print specification information, the print target file acquired from the print file storage  143 , the PDL data format information acquired from the apparatus information storage  142 , and the generated print management information. 
         [0172]    Following the above process, the print job generator  141  i) generates the PDL description print data by converting the data format of the inputted print target file with use of the printer driver corresponding to the data format indicated by the PDL data format information (step S 1705 ), ii) generates the PJL description print management information by converting the description language of the inputted print management information (step S 1706 ), iii) generates the print job from the generated PDL description print data and PJL description print management information, and the inputted second PJL description print setting information (step S 1707 ), and iv) outputs to the controller  144 . 
         [0173]    The controller  144  first specifies the network address of the image forming apparatus, the transmission source of the second print instruction information, based on the identification information of the image forming apparatus indicated by the second print instruction information and the information regarding the network address of the image forming apparatus stored in the apparatus information storage  142 . Next, the controller  144  transmits the inputted print job to the specified network address of the image forming apparatus (here, image forming apparatus  101 ), the transmitting source of the second print instruction information, via the communication controller  140  (step S 1708 ). 
         [0174]    (Summary of Overall Print Process of Push-Type Pull Printing System  100 ) 
         [0175]      FIG. 10  is an image diagram showing an overall process of a print process performed in the push-type pull printing system  100 . 
         [0176]    In  FIG. 10 , each reference numeral indicates the following.  101 : the image forming device  101 ,  104 : the server  104 ,  1000 : the second print instruction information,  1001 : the print data specification information,  1002 : the print setting information before being converted to the PJL commands,  1102 : the second PJL description print setting information after being converted into the PJL commands,  2000 : the print job,  2001 : the PJL description print management information,  2002 : the PDL description print data, and  3000 : the print process. 
         [0177]    As shown in  FIG. 10 , in the push-type pull printing system  100 , the print setting information  1002  (input or default print setting information) is set in the print condition setting screen displayed on the display part  1171  during the generation process of the second print instruction information in  FIG. 11 . And, before being transmitted to the server  104 , the description language of the above-mentioned print setting information  1002  is converted, by the image forming apparatus side, to PJL commands interpretable by the print device  120 , and following that, the print setting information  1002  is transmitted to the server  104  as the second PJL description print setting information  1102 . 
         [0178]    Then, unlike in the conventional push-type pull printing system in  FIG. 14  where the server  60  converts the description language of the print setting information  502  transmitted from the image forming apparatus  50  to PJL commands, the server  104  generates the print job  2000  including the transmitted second PJL description print setting information  1102  as it is. The print job  2000  is then transmitted to the image forming apparatus  101  which subsequently executes the print process  3000 . 
         [0179]    As a result of the above processes, the server side does not need to perform processes to convert the description language of the print setting information into the PJL commands which are interpretable by the print device. Accordingly, even in a case where an image forming apparatus using PJL commands uniquely created by a manufacturer is newly added to the push-type pull printing system  100 , it is not necessary to newly register those uniquely-created PJL commands every time to make the PJL commands correspond with the print setting information. Consequently, this allows an easy maintenance of the print job issuing function at the server side, and enhances smooth execution of print processes even when a setting is made on a print condition corresponding to the uniquely-set PJL commands. 
       &lt;Supplementary&gt; 
       [0180]    Up to now, the push-type pull printing system  100  in accordance with the present invention has been described based on the embodiment. However, it is obvious that the present invention is not limited to the present embodiment. 
         [0181]    (1) While a number of servers included in the push-type pull printing system  100  is one in the present embodiment, the number of servers is not limited to one, and can be multiple. Also, the push-type pull printing system  100  is applicable as long as there is at least one image forming apparatus included therein. 
         [0182]    (2) While the data format of the print target file stored in the print file storage  143  is converted into a PDL data format in the present embodiment, the data format of the print target file stored in the print file storage can be a PDL data format. In this case, if the PDL data format corresponds with the PDL data format interpretable by the image forming apparatus to which the print job is transmitted, the stored print target file can be issued as the print job without performing a conversion process of the print data format. 
         [0183]    Also, each image forming apparatus included in the push-type pull printing system  100  can have a PDL interpreter therein which can interpret a common PDL data format. This way, by uniformly using the common PDL data format which is interpretable by the above-mentioned PDL interpreter for the print target files stored in the print file storage  143 , the conversion process of the print data files can be omitted. 
         [0184]    Additionally, the data format of the print target file can be rasterized bitmap data. In this case also, the conversion process of the print data file can be omitted, resulting in the PDL interpreter becoming unnecessary at the image forming apparatus side. 
         [0185]    (3) While print target files are stored in the server  104  in the present embodiment, a file server can be provided to manage the print target files. By having the file server connected to the LAN  105 , the server  104  can acquire the print target files therefrom when issuing a print job. Specifically, among components of the server  104 , functions of the print file controller  1444  and the print file storage  143  can be performed by the additionally provided file server. 
         [0186]    (4) While a number of the print target files specified by the second print instruction information is one in the present embodiment, more than one print target files can be specified. 
         [0187]    In this case, setting of the print condition can be either performed separately for each print target file or performed collectively for all the specified print target files by setting a common print condition. 
         [0188]    In the above case, a print job corresponding to the print process of each print target file can be issued by the server  104  by having the central controller  119  prepare a set of data including print data specification information, input or default print setting information, and second print instruction information for each specified print target file and transmit these information to the server  104 .