Abstract:
An image forming apparatus of an example of the invention includes first connecting means for receiving image data, second connecting means for receiving control information for subjecting the image data to output control, the control information corresponding to the image data, third connecting means for communicating first print job information of the image data, and a display unit that displays the first print job information received by the third connecting means.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to an image forming apparatus and an image forming method for performing various kinds of processing on the basis of setting for various kinds of processing such as copying, facsimile transmission, scanning, or image filing. 
   2. Description of the Related Art 
   As it is well known, in recent years, there is an image forming apparatus that has plural functions such as a copy function, a facsimile function, a scanner function, a printer function, or an image filing function. Such an image forming apparatus is connected to, for example, an arbitrary number of personal computers (hereinafter referred to as PCs) and the outside via a network. Therefore, it is possible to capture data, which is captured by the image forming apparatus, into the PCs and transmit the data to the outside. 
   Conventionally, in the image forming apparatus that has plural functions such as a copy function, a facsimile function, a scanner function, a printer function, or an image filing function, a control panel is provided. A user performs various kinds of setting on the control panel. The user is also capable of applying the same setting as the setting on the control panel of the image forming apparatus such as conversion of a file format and instruction of copying to data stored in the image forming apparatus from a PC of a user. 
   Since such an image forming apparatus is connected to the arbitrary number of PCs via the network, the image forming apparatus receives print jobs for requesting printing from the respective PCs and sequentially processes plural print jobs received. 
   JP-A-2003-196056 discloses a constitution in which a printer receives, for one job, information such as image data from an application server, receives page control information such as output resolution and the number of prints from a client computer connected to the printer via a network, and combines the information and the page control information in the printer. 
   However, in the invention disclosed in JP-A-2003-196056, two interfaces, that is, an interface for transferring image data and an interface for transferring page control information are provided between the printer and a print controller. However, only information of one print job can be shared between the printer and the print controller. Thus, deletion of a job put in queuing by the controller cannot be performed from the printer side. 
   BRIEF SUMMARY OF THE INVENTION 
   It is an object of the invention to provide an image forming apparatus that can efficiently perform various kinds of processing and has high operability. 
   In order to attain the object of the invention, an image forming apparatus of the invention includes: first connecting means for receiving image data; second connecting means for receiving control information for subjecting the image data to output control, the control information corresponding to the image data; third connecting means for communicating first print job information of the image data; and a display unit that displays the first print job information received by the third connecting means. 
   Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter. 

   
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
     The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention, and together with the general description given above and the detailed description of the embodiments given below, serve to explain the principles of the invention. 
       FIG. 1  is a diagram showing an external appearance of an image forming apparatus according to an embodiment of the invention; 
       FIG. 2  is a block diagram showing a structure of the image forming apparatus according to the embodiment of the invention; 
       FIG. 3  is a block diagram showing structures of the image forming apparatus and an external controller according to the embodiment of the invention; 
       FIG. 4  is a diagram showing an external appearance of a control panel of the image forming apparatus according to the embodiment of the invention; 
       FIG. 5  is a diagram showing information displayed on the control panel of the image forming apparatus according to the embodiment of the invention; 
       FIG. 6  is a diagram showing information displayed on the control panel of the image forming apparatus according to the embodiment of the invention; 
       FIG. 7  is a diagram showing information displayed on the control panel of the image forming apparatus according to the embodiment of the invention; and 
       FIG. 8  is a flowchart showing operation in the control panel of the image forming apparatus according to the embodiment of the invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   An embodiment of the invention will be hereinafter explained with reference to the drawings.  FIG. 1  shows a main part of an image forming apparatus to which the invention is applicable. 
   An image forming apparatus  1  shown in  FIG. 1  includes an image forming unit body  2  for outputting image information as an output image referred to as, for example, hard copy or printout, a sheet feeding unit  3  capable of feeding a sheet (an output medium) of an arbitrary size used for image output to the image forming unit body  2 , and a scanner unit (an image reading unit)  4  that captures image information, which is an object subjected to image formation in the image forming unit body  2 , as image data from an object that holds the image information (hereinafter referred to as original). An automatic document feeder  5  that discharges, when an original is a sheet-like original, after formation of an image output or capture of image information (hereinafter referred to as reading) ends, the original, for which the reading ends, from a reading position to a discharge position and guides the next original to the reading position is integrally provided in the scanner unit  4 . An instruction input unit, that is, a control panel (an operation unit)  6  for instructing start of image formation in the image forming unit body  2  and start of reading of image information of an original by the scanner unit  4  is provided in a predetermined position of the image forming apparatus  1 , for example, at an end of a front surface of the image reading unit  4 . 
     FIG. 2  is a block diagram showing a structure of a control system of the image forming apparatus to which the invention is applicable. As shown in  FIG. 2 , in this image forming apparatus  1 , the control panel  6 , the scanner unit  4 , and a printer unit  12  are connected to a system control unit  11 . 
   The system control unit  11  controls the control panel  6 , the scanner unit  4 , the printer unit  12 , and the like. The system control unit  11  has various functions for performing various kinds of processing on the basis of signals supplied from the control panel  6 , the scanner unit  4 , and the printer unit  12 . 
   The control panel  6  has input keys  61 , a display unit  62  having a touch panel  62   a  built therein, and the like. An operation guide, keys (icons) selectable with the touch panel  62   a , and the like are displayed on the display unit  62  on the basis of display control by the system control unit  11 . On the control panel  6 , a user can input icons selectable with the input keys  61  or the touch panel  62   a . Information inputted by the user on the control panel  6  (information indicating icons selectable with the input keys  61  pressed by the user or the touch panel  62   a  touched by the user) is supplied to the system control unit  11 . 
   The scanner unit  4  converts an image of an original into image data on the basis of the control by the system control unit  11 . The scanner unit  4  converts the image of the original into color or monochrome digital image data. The scanner unit  4  supplies the digital image data serving as the image of the original read to the system control unit  11 . 
   The printer unit  12  prints an image on a sheet serving as an image formation medium on the basis of the control by the system control unit  11 . A result or the like of print processing by the printer unit  12  is notified to the system control unit  11 . The printer unit  12  performs color printing for forming a color image on the image formation medium on the basis of color image data or monochrome printing for forming a monochrome image on the image formation medium on the basis of monochrome image data. 
   The system control unit  11  includes, as shown in  FIG. 2 , a CPU (Central Processing Unit)  111 , a RAM (Random Access Memory)  112 , a ROM (Read Only Memory)  113 , an NVM (Non-volatile memory)  114 , a hard disk drive (HDD)  115 , an external interface  116 , a facsimile interface  117 , a page memory  118 , an image processing unit  119 , a display control unit  120 , or the like. 
   The CPU  111  executes a program stored in the ROM  113 , the nonvolatile memory  114 , or the HDD  115 . For example, the automatic document feeder  5  is realized by the CPU  111  executing a control program on the basis of a program and control data stored in the ROM  113 , the NVM  114 , or the HDD  115 . The CPU  111  executes display control of the display unit  62  in the control panel  6  on the basis of a program and control data stored in the NVM  114  or the ROM  113 . 
   The RAM  112  is a memory for temporarily storing data for work and storing data for reference. The RAM  112  is used as a main memory for executing various kinds of processing based on various control programs. For example, a control program and control data are read out to the RAM  112  at the time of an operation of the digital multifunction peripheral. At the same time, the RAM  112  stores information and the like that should be temporarily stored such as information indicating present setting content. 
   As the setting content, for example, in a copy mode, there are a copy magnification, the number of copies, and the like in addition to original setting and sheet setting. 
   The ROM  113  is a nonvolatile memory. For example, a control program, control data, and the like for controlling the image forming apparatus  1  are stored in the ROM  113 . Display data and the like displayed on the display unit  62  of the control panel  6  may be stored in the ROM  113 . 
   The NVM  114  is a rewritable nonvolatile memory. Data such as system setting information is stored in the NVM  114 . Display data and the like displayed on the display unit  62  of the control panel  6  may be stored in the NVM  114 . 
   The HDD  115  is a large capacity storage device. Various data such as various setting data, management data, control program, and control data are stored in the HDD  115 . Display data and the like displayed on the display unit  62  of the control panel  6  are also stored in the HDD  115 . Image data and the like read by the scanner unit  4  are also stored in the HDD  115 . Moreover, the HDD  115  may be used as a backup memory for various memories. 
   The external interface  116  has plural interfaces. The external interface  116  is connected to plural interfaces of an external controller  200  (see  FIG. 3 ) externally connected, respectively, and communicates data to the interfaces. In the image forming apparatus  1 , a network print function for printing print data from an external controller, which is connected to the image forming apparatus  1  by the external interface  116 , on a sheet is realized. 
   The facsimile interface  117  is an interface for transmitting and receiving facsimile data. In the image forming apparatus  1 , a facsimile function is realized using the facsimile interface  117 . For example, facsimile reception processing is realized by monochrome-printing facsimile data received by the facsimile interface  117  using the printer unit  12 . Facsimile transmission processing is realized by converting image data of an original read by the scanner unit  4  into facsimile data and transferring the facsimile data to a transmission destination using the facsimile interface  117 . 
   The page memory  118  is a memory in which image data and the like to be printed by the printer unit  12  are stored. For example, when the printer unit  12  performs print processing, color image data or monochrome image data of respective pages, which should be printed by the printer unit  12 , is expanded (stored) in the page memory  118 . 
   For example, the image processing unit  119  subjects data scanned by the scanner unit  4  to smoothing processing and performs high-image quality processing for printout. 
   The display control unit  120  controls a screen to be displayed on the display unit  62 . The display control unit  120  reads out a program and control data stored in the NVM  114  or the ROM  113  and displays a screen on the basis of input information of icons selectable with the input keys  61  or the touch panel  62   a  by a user. 
   Connection of a client PC, an external controller, and an image forming apparatus will be explained using  FIG. 3 . 
   Plural client PCs  300  are connected to the external controller  200  via a LAN. The external controller  200  is connected to the image forming apparatus  1  and controls the image forming apparatus  1  in response to a request from the client PC  300 . 
   Processing in the image forming apparatus  1  at the time when the user requests printing of image data using the client PC  300  will be explained. 
   The user can request, using a printer driver, printing of a document or the like created by an application of the client PC  300 . The external controller  200  receives print data from the client PC  300  via the LAN and generates image data and control information corresponding to the image data set by the user. The control information corresponding to the image data is, for example, information not depending on the image data such as resolution and the number of outputs and is information changeable by the user. 
   The external controller  200  has plural interfaces, namely, a Video ASIC  201  (Video Application Specific Integrated Circuit), a NIC  202  (Network Interface Card), and a UART  203  (Universal Asynchronous Receiver Transmitter). The Video ASIC  201  is a video interface for transferring image data generated by the external controller to the image forming apparatus  1 . The UART  203  is a UART interface for transferring control information corresponding to the image data to the image forming apparatus  1 . The NIC  202  is a network interface for transmitting and receiving print information and internal information of the image forming apparatus  1 . The print information is print job information displayed on the control panel  6  of the image forming apparatus  1  such as a file name and the number of prints of image data requested to be printed from the client PC  300 . The internal information of the image forming apparatus  1  is operation information of the image forming apparatus  1 , information on a residual amount of toner, and the like. 
   The Video ASIC  201  of the external controller  200  is connected to a CMYK circuit  130 , which is a video interface of the image forming apparatus  1 , by a VIDEO cable. The UART  203  of the external controller  200  is connected to a UART  132 , which is a UART interface of the image forming apparatus  1 , by a UART cable. The NIC  202  of the external controller  200  is connected to a NIC  131 , which is a network interface of the image forming apparatus  1 , by a NETWORK cable (a LAN cable in this embodiment). 
   The image forming apparatus  1  outputs image data received by the CMYK circuit  130  from the printer unit  12  on the basis of control information corresponding to image data received by the UART  132 . Print job information received by the NIC  131  is displayed on the touch panel  62   a  of the control panel  6 . 
   When plural print requests are sent from the client PC  300 , the external controller  200  stores image data requested by the plural print requests and control information corresponding to the image data in a not-shown storing unit provided in the external controller  200 . The external controller  200  controls the image data and the image data such that the image data can be transmitted to the image forming apparatus  1  via the VIDEO cable and the UART cable in an order of the print requests. 
   The external controller  200  creates a print job, which is information indicating a file name, the number of prints, and the like, on the basis of the image data requested to be printed from the client PC  300  and the control information corresponding to the image data. The external controller  200  transmits plural print jobs to the image forming apparatus  1  via the NETWORK cable that connects the NIC  202  of the external controller  200  and the NIC  131  of the image forming apparatus  1 . The image forming apparatus  1  displays the plural print jobs received on the control panel  6 . 
   The external controller  200  puts the image data and the control information corresponding to the image data stored in the not-shown storing unit on standby in the storing unit of the external controller  200  until a print order of the image data comes. 
   A structure of the control panel  6  will be explained.  FIG. 4  is an external view for explaining an example of the structure of the control panel  6 . As shown in  FIG. 4 , an input keys  61 , the display unit  62  having the touch panel  62   a  built therein, function selection keys  63 , and the like are provided on the control panel  6 . 
   The function selection keys  63  are keys for selecting various functions. As the function selection keys  63 , for example, a copy function selection key  64  for selecting a copy function, a filing box function selection key  65  for selecting a filing function for data, a scan function selection key  66  for selecting a scan function, a FAX function selection key  67  for selecting a facsimile function, a function extension key for selecting other extension functions, and the like are provided. 
   The input keys  61  are keys for inputting numbers and the like. The input keys  61  are used for inputting information such as the number of copies, a copy magnification, and a password for management. 
   The display unit  62  is constituted by a liquid crystal display device or the like having the touch panel  62   a  built therein. Various operation screens are displayed on the display unit  62 . Keys (icons) selectable with the touch panel  62   a  are displayed on the respective operation screens displayed on the display unit  62  in addition to an operation guide and the like. 
   The display control unit  120  of the system control unit  11  judges content of operation by the user or display content corresponding to operation states of the respective units. On the basis of this judgment, the display control unit  120  reads out display data, which should be displayed on the display unit  62 , from the NVM  114 , the ROM  113 , or a not-shown display memory and displays the display data on the control panel  6 . In other words, the display control unit  120  subjects the display unit  62  to display control according to content of operation by the user, operation states of the respective units, or the like. 
   It is assumed that, as shown in  FIG. 5 , plural print requests are sent from the client PC  300  to the external controller  200 . The plural print requests may be sent from an identical client PC  300  or may be sent from different client PCs  300  separately. 
   When the plural print requests are sent from the client PC  300  to the external controller  200 , print jobs are displayed on the control panel  6  in an order of the print requests. For example, it is assumed that plural print requests are sent from the client PC  300  in an order of Martini.doc, Alexander.xls, Black Velvet.ppt, Bellini.pdf, Alaska.txt, and Stinger.mpp. Then, the six files are displayed as print jobs on the control panel  6  of the image forming apparatus  1  according to a print order. 
   In an example described in this embodiment, only file names are displayed on the control panel  6  as print jobs. The print jobs displayed on the control panel  6  are sequentially updated in such a manner that, for example, when printing of a print job currently being printed ends, display of the print job is deleted. Moreover, when a new print request is sent from the client PC  300 , a new print job is additionally displayed under Alaska.txt and Stinger.mpp. 
   For example, deletion of printing of the file Black Velvet.ppt by the user is explained. The user selects a print job of a file, which the user desires to delete, using the input keys  61  or the touch panel  62   a  of the image forming apparatus  1 . For example, as shown in  FIG. 5 , it is also possible to display characters of the print job selected in a light color to indicate that deletion of the print job is requested. 
   When the user selects a print job to be deleted, Black Velvet.ppt, the CPU  111  of the image forming apparatus  1  transmits information on deletion of the print job Black Velvet.ppt to the NIC  202  of the external controller  200 , which is connected to the image forming apparatus  1  by the NETWORK cable, via the NIC  131  of the image forming apparatus. When the external controller  200  receives the information on deletion of the print job Black Velvet.ppt from the image forming apparatus  1 , the external controller  200  deletes image data of Black Velvet.ppt received from the client PC  300  and control information corresponding to the image data from the not-shown storing unit of the external controller  200 . When the deletion of the image data of Black Velvet.ppt and the control information corresponding to the image data from the not-shown storing unit of the external controller  200  is completed, the external controller  200  transmits information indicating the remaining print jobs excluding the print job Black Velvet.ppt from the NIC  202  of the external controller  200  to the image forming apparatus  1  via the NETWORK cable. The CPU  111  of the image forming apparatus  1  temporarily stores the information indicating the print jobs received from the external controller  200  in the NVM  114  or the ROM  113 . The display control unit  120  of the image forming apparatus  1  subjects the print jobs displayed on the display unit  62  to display control to change a state shown before the deletion in  FIG. 5  to a state shown after the deletion. 
   In other words, the display control unit  120  subjects the print jobs to display control to change to a state in which the print job Black Velvet.ppt is deleted. After the deletion of the print job Black Velvet.ppt, as shown in  FIG. 5 , Bellini.pdf, Alaska.txt, and Stinger.mpp are moved up in the display of the print jobs. 
   This makes it possible to delete a file, which is not required to be printed, using the input keys  61  or the touch panel  62   a  of the image forming apparatus  1  without applying loads to the image forming apparatus  1 . 
   For example, a change of a print order of the file Alexander.xls by the user is explained. The user selects a print job, a print order of which is changed, using the input keys  61  or the touch panel  62   a  of the image forming apparatus  1 . For example, as shown in  FIG. 6 , it is also possible to display characters of the print job selected in a light color to indicate that the change of a print order is requested. 
   The user selects a print job, a print order of which is changed, Alexander.xls, and sets a print order change to place Alexander.xls after Alaska.txt using the input keys  61  or the touch panel  62   a.    
   The CPU  111  of the image forming apparatus  1  transmits information on the print order change of Alexander.xls to the NIC  202  of the external controller  200 , which is connected to the image forming apparatus  1  by the NETWORK cable, via the NIC  131  of the image forming apparatus. 
   When the external controller  200  receives the information on the print order change of the Alexander.xls from the image forming apparatus  1 , the external controller  200  sets image data of Alexander.xls and control information corresponding to the image data to be placed after printing of the file Alaska.txt. In other words, the external controller  200  changes a setting to transmit image data of Alaska.txt and control information corresponding to the image data stored in the not-shown storing unit to the image forming apparatus  1  and, then, transmit image data of Alexander.xls and control information corresponding to the image data to the image forming apparatus  1 . When the order change for transmitting the image data of Alexander.xls and the control information corresponding to the image data to the image forming apparatus  1  is completed, the external controller  200  transmits information indicating the print jobs after the order change from the NIC  202  of the external controller  200  to the image forming apparatus  1  via the NETWORK cable. The CPU  111  of the image forming apparatus  1  temporarily stores the information indicating the print jobs received from the external controller  200  in the NVM  114  or the ROM  113 . The display control unit  120  of the image forming apparatus  1  subjects the print jobs displayed on the control panel  6  to display control to change a state shown before the change in  FIG. 6  to a state shown after the change. 
   In other words, the display control unit  120  subjects the print job Alexander.xls to display control to change the state before the change to a state in which Alexander.xls is placed after Alaska.txt. 
   This makes it possible to set a print order of a file, which is not required to be printed quickly, later than that in an initial setting using the input keys  61  or the touch panel  62   a  of the image forming apparatus  1  without applying loads to the image forming apparatus  1 . It is also possible to set a print order of a file, which is required to be printed quickly, earlier than that in the initial setting using the input keys  61  or the touch panel  62   a  of the image forming apparatus  1  without applying loads to the image forming apparatus  1 . 
   For example, suspension of printing of a file Black Velvet.ppt by the user is explained. The user selects a print job, printing of which is suspended, using the input keys  61  or the touch panel  62   a  of the image forming apparatus  1 . For example, as shown in  FIG. 6 , it is also possible to display characters of the print job selected in a light color to indicate that suspension of printing is requested. 
   The user selects a print job, printing of which is suspended, Black Velvet.ppt. The CPU  111  of the image forming apparatus  1  transmits information on suspension of printing of Black Velvet.ppt to the NIC  202  of the external controller  200 , which is connected to the image forming apparatus  1  by the NETWORK cable, via the NIC  131  of the image forming apparatus. 
   When the external controller  200  receives the information on suspension of printing of Black Velvet.ppt from the image forming apparatus  1 , the external controller  200  sets printing of the file Black Velvet.ppt to be suspended. In other words, the external controller  200  sets image data of Black Velvet.ppt and control information corresponding to the image data stored in the not-shown storing unit of the external controller  200  not to be transmitted to the image forming apparatus  1  even if an order of the print job Black Velvet.ppt comes. The external controller  200  transmits the image data of Bellini.pdf, which is a print job following Black Velvet.ppt, and control information corresponding to the image data to the image forming apparatus. 
   When the setting for suspending transmission of the image data of Black Velvett.ppt and the control information corresponding to the image data to the image forming apparatus is completed, the external controller  200  transmits information indicating the print jobs after the suspension setting from the NIC  202  of the external controller  200  to the image forming apparatus  1  via the NETWORK cable. The CPU  111  of the image forming apparatus  1  temporarily stores the information indicating the print jobs received from the external controller  200  in the NVM  114  or the ROM  113 . The display unit  120  of the image forming apparatus  1  subjects the print jobs displayed on the control panel  6  to display control to change a state shown before the suspension in  FIG. 7  to a state shown after the suspension. 
   In other words, the display control unit  120  displays an indication that printing of the print job Black Velvet.ppt is not resumed until the user instructs resumption of the printing. Since the file Bellini.pdf, which is a print job following the Black Velvet.ppt, is printed earlier than the file Black Velvet.ppt, the display control unit  120  displays an indication that the print job is printed ahead of the preceding job as shown after the suspension in  FIG. 6 . 
   This makes it possible to suspend printing of a file with a large size, which is not required to be printed quickly, using the input keys  61  or the touch panel  62   a  of the image forming apparatus  1  without applying loads to the image forming apparatus  1 . This is convenient for the user. 
   For example, immediate printing of a file Alexander.xls by the user is explained. The user is also capable of selecting a print job, printing of which is started immediately, using the input keys  61  or the touch panel  62   a  of the image forming apparatus  1 . 
   The user selects a print job to be immediately printed, Alexander.xls, using the input keys  61  or the touch panel  62   a.    
   The CPU  111  of the image forming apparatus  1  transmits information on immediate printing of Alexander.xls to the NIC  202  of the external controller  200 , which is connected to the image forming apparatus  1  by the NETWORK cable, via the NIC  131  of the image forming apparatus. 
   When the external controller  200  receives the information on immediate printing of Alexander.xls from the image forming apparatus  1 , the external controller  200  changes a setting to immediately transmit image data of Alexander.xls and control information corresponding to the image data to the image forming apparatus  1 . When the change for immediate transmission of the image data of Alexander.xls and the control information corresponding to the image data to the image forming apparatus  1  is completed, the external controller  200  transmits information indicating the print jobs after the setting for immediate printing of Alexander.xls from the NIC  202  of the external controller  200  to the image forming apparatus  1  via the NETWORK cable. The CPU  111  of the image forming apparatus  1  temporarily stores the information indicating the print jobs received from the external controller  200  in the NVM  114  or the ROM  113 . The display control unit  120  of the image forming apparatus  1  performs display control to display the print jobs on the control panel  6 . In this case, for example, it is also possible to display characters of the print job Alexander.xls in a light color to indicate that immediate printing is performed. 
   This makes it possible to immediately print a file, which is required to be printed quickly, using the input keys  61  or the touch panel  62   a  of the image forming apparatus  1  without applying loads to the image forming apparatus  1 . 
   The selection of a print job in the image forming apparatus  1  explained above will be explained using a flowchart of  FIG. 8 . 
   Print data described in the PDL (Page Description Language) is transmitted from the client PC  300  to the external controller  200  (step S 100 ). The external controller  200  interprets the PDL (Page Description Language) of the print data received using an RIP (Raster Image Processor), expand the print data into a raster image, and generates image data. The image data generated is transmitted from the Video ASIC  201  of the external controller  200  to the CMYK circuit  130  of the image forming apparatus  1  via the VIDEO cable. The external controller  200  transmits control information corresponding to the image data from the UART  203  of the image forming apparatus  1  to the UART  116  of the image forming apparatus  1  via the UART cable. 
   A not-shown CPU of the external controller  200  transmits information indicating print jobs from the NIC  202  of the external controller  200  to the NIC  202  of the image forming apparatus  1  via the NETWORK cable on the basis of an order of plural print requests transmitted from the client PC  300  (step S 101 ). 
   The CPU  111  of the image forming apparatus  1  temporarily stores the information indicating the print jobs transmitted from the external controller  200  in the NVM  114  or the ROM  113  to make it possible to display the print jobs on the control panel  6  (step S 102 ). 
   The display control unit  120  displays the print jobs on the control panel  6  in accordance with a display setting of the print jobs by the user. The user can check the display of the print jobs on the control panel  6  (step S 103 ). 
   The user is capable of selecting a print job displayed on the control panel  6  and making a predetermined request concerning the print job selected (step S 104 ). 
   It is assumed that the user selects one print job out of plural print jobs displayed on the control panel  6  and selects shift of a print order of the print job selected (step S 105 ). The CPU  111  of the image forming apparatus  1  transmits information on the change of the print order of the print job selected from the NIC  131  of the image forming apparatus  1  to the NIC  202  of the external controller  200  via the NETWORK cable. 
   The external controller  200  performs control to transmit image data and control information corresponding to the image data stored in the not-shown storing unit of the external controller  200  to the image forming apparatus  1  in an order based on the information on the change of the print order. The external controller  200  transmits information indicating the print job after the change of the order from the NIC  202  of the external controller  200  to the NIC  131  of the image forming apparatus  1  via the NETWORK cable. 
   The CPU  111  of the image forming apparatus  1  temporarily stores the information indicating the print jobs after the change of the order in the NVM  114  or the ROM  113  to make it possible to display the print jobs on the control panel  6 . An order of the print job selected is changed and displayed on the control panel  6  (step S 106 ). 
   The printer unit  2  of the image forming apparatus  1  outputs image data in the order of the print jobs displayed on the control panel  6  (step S 107 ). Printing of all the print jobs ends (step S 108 ). 
   It is assumed that the user selects one print job out of the plural print jobs displayed on the control panel  6  and selects deletion of printing of the print job selected (step S 109 ). The CPU  111  of the image forming apparatus  1  transmits information on the deletion of the print job selected from the NIC  131  of the image forming apparatus  1  to the NIC  202  of the external controller  200  via the NETWORK cable. 
   The external controller  200  performs control to delete the image data and the control information corresponding to the image data stored in the not-shown storing unit of the external controller  200  on the basis of the information on the deletion of the print job. The external controller  200  transmits information indicating the remaining print jobs after deleting the print job selected from the NIC  202  of the external controller  200  to the NIC  131  of the image forming apparatus  1  via the NETWORK cable. 
   The CPU  111  of the image forming apparatus  1  temporarily stores the information indicating the print jobs after deleting the print job selected in the NVM  114  or the ROM  113  to make it possible to display the print jobs on the control panel  6 . The print job selected is deleted and the remaining print jobs are displayed on the control panel  6  (step S 110 ). 
   Image data of the print job, for which deletion of printing is selected, is not printed and the printer unit  2  of the image forming apparatus  1  outputs image data in an order of the print jobs displayed on the control panel  6  (step S 111 ). Printing of all the print jobs ends (step S 108 ). 
   It is assumed that the user selects one print job out of the plural print jobs displayed on the control panel  6  and selects suspension of printing of the print job selected (step S 112 ). The CPU  111  of the image forming apparatus  1  transmits information on the suspension of the print job selected from the NIC  131  of the image forming apparatus  1  to the NIC  202  of the external controller  200  via the NETWORK cable. 
   The external controller  200  performs control to transmit the image data and the control information corresponding to the image data stored in the not-shown storing unit of the external controller  200  to the image forming apparatus  1  on the basis of the information on the suspension. 
   The external controller  200  transmits information indicating the print jobs after setting the suspension of the print job selected from the NIC  202  of the external controller  200  to the NIC  131  of the image forming apparatus  1  via the NETWORK cable. 
   The CPU  111  of the image forming apparatus  1  stores the information indicating the print jobs after setting the suspension of the print job selected in the NVM  114  or the ROM  113  to make it possible to display the print jobs on the control panel  6 . The print job selected is displayed in a suspended state on the control panel  6  (step S 113 ). 
   The printer unit  2  of the image forming apparatus  1  keeps the print job, for which suspension is selected, in a print wait state until the user instructs resumption of printing (step S 114 ). The printer unit  2  outputs the image data in an order of the print jobs displayed on the control panel  6  excluding the print job, for which suspension is selected, and print jobs of all the print jobs ends (step S 108 ). 
   It is assumed that the user selects one print job out of the plural print jobs displayed on the control panel  6  and selects printing of the print job selected (step S 115 ). The CPU  111  of the image forming apparatus  1  transmits print start information for immediately printing the print job selected from the NIC  131  of the image forming apparatus  1  to the NIC  202  of the external controller  200  via the NETWORK cable. 
   The external controller  200  performs control to start printing from the image data and the control information corresponding to the image data stored in the not-shown storing unit of the external controller  200  on the basis of the print start information. The external controller  200  transmits information indicating that the print job selected is printed from the NIC  202  of the external controller  200  to the NIC  131  of the image forming apparatus  1  via the NETWORK cable. 
   The CPU  111  of the image forming apparatus  1  temporarily stores the information indicating that the print job selected is in a printing state in the NVM  114  or the ROM  113  to make it possible to display the print jobs on the control panel  6 . The print job selected is deleted and the remaining print jobs are displayed on the control panel  6 . 
   The printer unit  2  of the image forming apparatus  1  prints image data of the print job, for which immediate printing is selected (step S 116 ). The printer unit  2  outputs image data of the remaining print jobs displayed on the control panel  6  in an order of the print jobs displayed and printing of all the print jobs ends (step S 108 ). 
   Since the UART cable is a cable for serial communication, if information with a large amount of data such as names of jobs is communicated, it is likely that deficiencies such as communication abnormality occur. It is possible to reduce loads of communication due to the UART cable and eliminate occurrence of deficiencies by performing operation of print jobs through the NETWORK cable. 
   Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.