Abstract:
There is provided an image forming device which comprises: a print unit; a connection unit to which an external device is detachably attachable; a print control unit configured to control the print unit in accordance with print target data read from the external device attached to the connection unit to form an image corresponding to the print target data on a recording medium; a storage unit used to store the print target data which has been printed via the print unit; an authentication information input unit configured to accept input of authentication information; and a judgment unit configured to judge whether to permit execution of reprinting of the print target data stored in the storage unit in accordance with the authentication information.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]    This application claims priority under 35 U.S.C. §119 from Japanese Patent Application No. 2007-021963, filed on Jan. 31, 2007. The entire subject matter of the application is incorporated herein by reference. 
       BACKGROUND  
       [0002]    1. Technical Field 
         [0003]    Aspects of the present invention relate to an image forming device having a direct print function of directly acquiring image data from an external storage device and executing a printing operation for the acquired image data. 
         [0004]    2. Related Art 
         [0005]    Image forming devices having the direct print function have been widely used. An example of such an image forming device is disclosed in Japanese Patent Provisional Publication No. 2005-280285 (hereafter, referred to as JP2005-280285A). In this publication, it is disclosed that a digital camera which is a USB device corresponding to a storage class can be connected to a printer. When image data is read from the digital camera connected to the printer, a printing unit of the printer is activated to print an image corresponding to the image data. The image data which has been targeted for the printing operation is automatically stored in internal storage of the printer. 
         [0006]    By thus automatically storing, in the internal storage of the printer, the image data for which the printing operation has been executed, it is possible to reprint the image for which the printing operation has been executed, through use of the printer alone. That is, for the purpose of reprinting images, connection of the digital camera to the printer is not required. 
       SUMMARY  
       [0007]    However, according to the above mentioned configuration of the printer, there is a possibility that an image corresponding to certain image data which has been stored in the printer by a certain user is reprinted through the printer regardless of the certain user&#39;s intention. That is, images that the certain user does not want to print might be printed through the printer. 
         [0008]    Aspects of the present invention are advantageous in that an image forming device capable of reprinting an image for which a printing operation has been executed, while maintaining excellent security of stored image data is provided. 
         [0009]    According to an aspect of the invention, there is provided an image forming device which comprises: a print unit; a connection unit to which an external device is detachably attachable; a print control unit configured to control the print unit in accordance with print target data read from the external device attached to the connection unit to form an image corresponding to the print target data on a recording medium; a storage unit used to store the print target data which has been printed via the print unit; an authentication information input unit configured to accept input of authentication information; and a judgment unit configured to judge whether to permit execution of reprinting of the print target data stored in the storage unit in accordance with the authentication information. 
         [0010]    In this configuration, whether to permit the reprinting is judged based on the authentication information. By imposing a condition on execution of the reprinting, the reprinting is prevented from being executed if the condition is not satisfied. Therefore, security regarding the reprinting can be enhanced. 
         [0011]    According to another aspect of the invention, there is provided an image forming device which comprises: a print unit; a connection unit to which an external device is detachably attachable; a storage unit used to store print target data which has been printed via the print unit; and a print control unit configured to store, at a stage where the print target data read from the external device attached to the connection unit is stored in the storage unit, authentication information used to judge whether to permit reprinting of the print target data in the storage unit. 
         [0012]    With this configuration, it is possible to prevent print data remaining in the image forming device from being printed freely by another user. That is, security of print data can be achieved. 
         [0013]    According to another aspect of the invention, there is provided a method of controlling reprinting executed on an image forming device, comprising the steps of: controlling a print unit in accordance with print target data read from an external device attached to the image forming device to form an image corresponding to the print target data on a recording medium; storing the print target data which has been printed via the print unit in a storage unit; accepting input of authentication information; and judging whether to permit execution of reprinting of the print target data stored in the storage unit in accordance with the authentication information. 
         [0014]    With this configuration, it is possible to prevent print data remaining in the image forming device from being printed freely by another user. That is, security of print data can be achieved. 
         [0015]    It is noted that various connections are set forth between elements in the following description. It is noted that these connections in general and unless specified otherwise, may be direct or indirect and that this specification is not intended to be limiting in this respect. Aspects of the invention may be implemented in computer software as programs storable on computer-readable media including but not limited to RAMs, ROMs, flash memory, EEPROMs, CD-media, DVD-media, temporary storage, hard disk drives, floppy drives, permanent storage, and the like. 
     
    
     
       BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS  
         [0016]      FIG. 1  is a perspective view of a printer according to an embodiment. 
           [0017]      FIG. 2  illustrates an outer appearance of a computer. 
           [0018]      FIG. 3  illustrates an example of a print control screen through which file output is designated. 
           [0019]      FIG. 4  illustrates a configuration of a touch panel. 
           [0020]      FIG. 5  is a block diagram of a control system of the printer. 
           [0021]      FIG. 6  is a flowchart illustrating a print/reprint process to be executed by a CPU of the printer. 
           [0022]      FIG. 7  illustrates examples of contents displayed in a display box. 
           [0023]      FIG. 8  illustrates an example of a job selection menu displayed in the display box. 
           [0024]      FIG. 9  illustrates examples of contents displayed in the display box. 
           [0025]      FIG. 10  illustrates transitions of onscreen representation for inputting a job name. 
           [0026]      FIG. 11  illustrates transitions of onscreen representation for inputting a user name. 
           [0027]      FIG. 12  illustrates examples of contents displayed in the display box. 
           [0028]      FIG. 13  illustrates examples of contents displayed in the display box. 
           [0029]      FIG. 14  illustrates transitions of onscreen representation for inputting a password. 
           [0030]      FIG. 15  illustrates examples of contents displayed in the display box. 
           [0031]      FIG. 16  illustrates a relationship between specifications of the printer and items of the job selection menu. 
           [0032]      FIG. 17  illustrates an outer appearance of a multifunction device. 
       
    
    
     DETAILED DESCRIPTION  
       [0033]    Hereafter, an embodiment according to the invention will be described with reference to the accompanying drawings. 
         [0034]      FIG. 1  is a perspective view of a printer  10  according to an embodiment. As shown in  FIG. 1 , the printer  10  includes a body case  11  having a box shape. On the lower side of the body case  11 , a sheet supply cassette  15  is provided. The upper wall of the body case  11  has a recessed part where the upper wall gradually sinks toward the rear side to form a sheet ejection tray  17 . 
         [0035]    In the body case  11 , various units such as a printing engine  61  are accommodated. In the printer  10 , a sheet is supplied from the sheet supply cassette  15  to the printing engine  61  to form a desired image on the sheet. After an image is formed on the sheet, the sheet is ejected to the sheet ejection tray  17  through a sheet ejection slot  18 A. On the front of the one edge part (on the front left side in  FIG. 1 ) of the top wall of the body case  11 , a power switch  21  and LEDs  22  are provided. The other edge part of the top wall is formed to have a larger width, and a touch panel  31  is formed on the other edge part. 
         [0036]    In the front wall of the body case  11 , a manual feeding slot  41  which is used to manually feed sheets is formed. On the lower right side with respect to the manual feeding slot  41 , a slot  45  used to attach an external memory (e.g., a USB memory  70 ) is provided. 
         [0037]    In the following, it is assumed that three files IMG-A.JPG, DOC-B.PDF and PIC-C.TIF are stored in the USB memory  70 . To store the three files in the USB memory  70 , a user creates each file and saves the created three files in the USB memory  70  through a computer Z (see  FIG. 2 ). As shown in  FIG. 2 , the computer Z includes a display  120 , a main body  110 , and a user interface (e.g., a keyboard  130  and a mouse  140 ). 
         [0038]    The user is able to print a file through use of the computer z. That is, the user is able to control the printer  10  through a print control screen (see  FIG. 3 ) displayed on the display  120  of the computer z to print a file which was created on the computer z. The user is also able to directly print a file on the printer  10  without using the computer z. By attaching an external memory (e.g., the USB memory  70 ) to the slot  45  of the printer  10 , the user is able to directly print a file stored in the external memory on the printer  10 . Such a direct print operation will be described in detail later. 
         [0039]    Hereafter, the touch panel  31  is explained in detail. As shown in  FIG. 4 , the touch panel  31  has a rectangular shape. A display box  33  is formed on the upper half part of the touch panel  31 . A display area DA is located on a central part of the display box  33 . On the display area DA, information is displayed in response to user operations to support input operations conduced by a user through various keys. 
         [0040]    On the lower side with respect to the display box  33 , a ten key  35 , up and down keys  36 , and left and right keys  37  are provided. Further, a mode selection key  38  is provided in the lower left corner. Three keys  33 A,  33 B and  33 C are also formed in the display box  31  as displayed items. The statuses of the three keys  33 A,  33 B and  33 C are controlled in accordance with the proceedings of the user input operation. For example, in accordance with the user operation, the three keys  33 A,  33 B, and  33 C appear on the display box  33 , the three keys are removed from the display box, or displayed contents in each of the three keys  33 A,  33 B, and  33 C are changed. For example, a menu “Print” is displayed on the key  33 C at a certain stage, while a menu “Confirmation” is displayed on the key  33 C in a different stage. 
         [0041]    As described in detail below, the user is able to input various instructions to the printer  10  while referring to contents displayed on the display area DA. The printer  10  has two modes including a print mode and a reprint mode. By operating the mode selection key  38 , the user is able to select one of the two modes. The print mode is a mode where the USB memory  70  is attached to the slot  45  so that a file in the USB memory  70  is targeted for the direct print. On the other hand, the reprint mode is a mode where a printed document made by the direct print on the printer  10  is outputted again by the printer  10  (i.e., a mode where the document is reprinted). 
         [0042]      FIG. 5  is a block diagram of a control system of the printer  10 . As shown in  FIG. 5 , the printer  10  includes a CPU  51 , a ROM  53 , a RAM  55 , and a non-volatile memory  57 . Further, the print engine  61 , the touch panel  31 , a USB interface  65  are connected to the CPU  51 . 
         [0043]    In the ROM  53 , various programs, settings and initial values for controlling internal units of the printer  10  are stored. When a process is executed, a program and data are loaded on the RAM  55  from the ROM  53 . By loading and executing a program, a process shown in  FIG. 6  is executed by the CPU  51  so that printing operations including the above mentioned print mode and the reprint mode are executed. 
         [0044]    The process shown in  FIG. 6  starts running, for example, when the printer  10  is tuned ON. First, the CPU  51  judges whether the USB memory  70  is connected o the printer  10  (step S 10 ). Typically, at a stage immediately following the power on of the printer  10 , the USB memory  70  is not connected to the printer  10 . In this case, the judgment result of step S 10  is “NO”. Then, control proceeds to step S 100  where the CPU  51  judges whether the reprint mode is selected. Typically, at the stage immediately following the power on of the printer  10 , the CPU  51  judges that the reprint mode is not selected. Therefore, in this case, steps S 10  and S 100  are repeated, and the printer  10  moves to a so-called standby mode. 
         [0045]    The standby mode is released when a user accesses the printer  10 , for example, by inserting the USB memory  70  into the slot  45  or operating the mode selection key  38  to select a desired mode. When the user inserts the USB memory  70  into the slot  45  and then selects the print mode through the mode select ion key  38 , the CPU  50  judges step S 10  and S 20  to be “YES”. Then, control proceeds to step S 30 . 
         [0046]    In step S 30 , the CPU  51  reads files from the USB memory  70 . Then, file names of the files read from the USB memory  70  are displayed on the display box  33  of the touch panel  31  (see  FIG. 7 ). In  FIG. 7 , “jpg”, “pdf” and “tif” represent extensions of the files. 
         [0047]    As shown in  FIG. 7 , a selection bar  34 A is also displayed on the display box  33  to be used as a cursor. As shown in  FIG. 7 , the user is able to move the selection bar  34 A between positions where the file names are displayed by operating the up and down keys  36  of the touch panel  31 . 
         [0048]    When the user operates the “Next” key  33 C in a state where the selection bar  34 A is at the desired position, the user is able to select the file at which the selection bar  34 A is situated as a print target. In the following, it is assumed that the file IMG-A.JPG is selected as a print target (see the fourth stage screen  374  in  FIG. 7 ). 
         [0049]    After the print target is selected as described above, onscreen representation changes to one shown in the first stage screen  381  in  FIG. 8 . In the first stage screen of  FIG. 8 , a job selection menu including “Print Once”, “Reprintable” and “Secure-Reprintable” is displayed. The user is allowed to select one of items of the job selection menu by operating the touch panel  31 . More specifically, the selection bar  34 A is moved between the items “Print Once”, “Reprintable” and “Secure-Reprintable” in this order by operating the up and down keys  36  of the touch panel  31  (see  FIG. 8 ). By moving the selection bar  34 A to a position of a desired item and then pressing the key  33 C, the user is able to select the desired item. After the desired item is thus selected, step S 30  is finished. Then, control proceeds to step S 40 . 
         [0050]    As described in detail below, the process “Print Once” is defined as a process where print target data is printed once. The process “Reprintable” is defined as a process where, after print target data is printed once, a job for reprinting (including the print target data to be reprinted) is stored and no password is required in the reprinting. The process “Secure-Reprintable” is defined as a process where, after print target data is printed once, a job for reprinting (including the print target data to be reprinted) is stored and in the reprinting a password is required. 
         [0051]    First, the case where the “Print Once” is selected is explained. In this case, the CPU  51  judges that “Secure-Reprintable” is not selected (S 40 : NO). Then, control proceeds to step S 60  where the CPU  51  judges whether “Reprintable” is selected. Since the “Print Once” is selected, the CPU  51  judges that “Reprintable” is not selected (S 60 : NO). Then, control proceeds to step S 81 . 
         [0052]    In step S 81 , the CPU  51  executes a raster image process (RIP) where the image data (i.e., the file IMG-A.JPG) selected as the print target is converted to a bitmap image to make raster data. Next, in step S 83 , the CPU  51  executes the print operation where the print engine  61  is driven in accordance with the raster data. Thus, an image corresponding to the file IMG-A.JPG is formed on a sheet. That is, the direct print of the file IMG-A.JPG is finished. After, the steps for the “Print Once” are finished, if the USB memory  70  is pulled out from the slot  45  of the printer  10 , control enters the loop process of steps S 10  and S 100  again. 
         [0053]    As described above, in the case where the “Print Once” is selected, the raster data of the print target (i.e., the file IMG-A.JPG) does not remain in the printer  10 . Therefore, if the “Print Once” is selected, it is impossible to reprint the file IMG-A.JPG on the printer  10 . To reprint the file IMG-A.JPG, the user is required to insert the USB memory  70  into the slot  45  again and then to conduct the user operation through the touch panel  31  (see  FIG. 16 ). 
         [0054]    It is understood that step S 60  serves to selectively execute, in accordance with a user operation, a process for storing the raster data in the non-volatile memory  57  and a process for not storing the raster data in the non-volatile memory  57 . 
         [0055]    Hereafter, the case where the “Reprintable” is selected is described. When the item “Reprintable” is selected on the screen shown in  FIG. 8 , the onscreen representation changes to one shown in the first state screen in  FIG. 9  to show a job name. Although in the example shown in  FIG. 9  a filename of the file (i.e., the file IMG-A.JPG) which has been selected in step S 30  is displayed as a job name, the job name can be modified by pressing the edit key  33 B displayed on the lower center part of the display box  33  and then inputting a favorable job name by using various keys including the up and down keys  36  and left and right keys  37  as shown in transitions of the onscreen representation shown in  FIG. 10 . 
         [0056]    By pressing the “Next” key  33 C on the first stage screen of  FIG. 9 , selection of the job name (the job name “IMG-A_JPG” in this example) is confirmed. Then, onscreen representation changed to the second stage screen in  FIG. 9 . 
         [0057]    In the second stage screen of  FIG. 9 , “TOM” is displayed as a user name. Actually, no user name is displayed on the second stage screen of  FIG. 9  immediately after the selection of the job name, as shown in the upper left screen  411  in  FIG. 11 . Therefore, the user enters a user name through this screen using the keys including the up and down keys  36  and the left and right keys  37 . 
         [0058]    After the user enters the user name and then presses the “Confirmation” key  33 C on the rightmost screen  414  in  FIG. 11 , the onscreen representation moves to a state of the second stage careen of  FIG. 9 . In this stage, the “Print” key  33 C is displayed at the lower right part of the display box  33 . 
         [0059]    By completing the above user operation, the process of step S 30  is finished. Then, control proceeds to step S 40 . In step S 40 , the CPU  51  judges whether the “Secure-Reprintable” is selected. Since the currently selected item is “Reprintable”, the judgment result of S 40  is NO. In step S 60 , the CPU  51  judges that the “Reprintable” is selected (S 60 : YES). Then, control proceeds to step S 61 . 
         [0060]    Similarly to step S 81  which is executed when the item “Print Once” is selected, the CPU  51  converts the file of the print target (i.e., the file IMG-A.JPG) to a bitmap image to create raster data. Then, control proceeds to step S 63 . If the “Print” key  33 C of the second stage screen in  FIG. 9  is selected in this stage, the CPU  51  drives the print engine  61  in accordance with the raster data to print an image corresponding to the file IMG-A.JPG on a sheet (step S 63 ). Thus, direct print of the file IMG-A.JPG is executed. 
         [0061]    After the file IMG-A.JPG is printed as described above, control proceeds to step S 71  to register a reprint job. More specifically, the CPU  51  allocates an area exclusive to the registering in the non-volatile memory  57 , and then writes the job name (i.e., “IMG-A_JPG” which has been designated by the user in step S 30 ) and the user name (i.e., “TOM”) in the allocated area. Then, control proceeds to step S 75 . 
         [0062]    In step S 75 , the raster data of the file (i.e., the file IMG-A.JPG) which has been targeted for the printing in step S 63  is additionally stored in the area allocated at step S 71 . Thus, the raster data of the file of the print target, the job name inputted by the user and the user name are stored as information representing a job. The registration of a reprint job is thus finished (step S 77 ). If the USB memory  70  is pulled out from the slot  45  afterward, control enters the loop process of steps S 10  and S 100  again. 
         [0063]    As described above, if the “Reprintable” is selected from the job selection menu, the raster data of the print target (i.e., the file IMG-A.JPG) of the direct print is stored in the printer  10  as a reprint job. Therefore, if the “Reprintable” is selected, it is possible to reprint the file IMG-A.JPG through use of the printer  10  alone (see  FIG. 16 ). 
         [0064]    To execute the reprinting, the user is required to select the reprint mode thorough the mode selection key  38  of the touch panel  31 . If the reprint mode is selected, the judgment result of step S 100  is “YES”. In this case, control proceeds to step S 110 . 
         [0065]    In step S 110 , user names currently registered are displayed in the display box  33  (see the first stage screen of  FIG. 12 ), and the selection bar  34 A is also displayed in the display box  33 . By operating the up and down keys  36 , the selection bar  34 A moves between the displayed user names so that the user can select one of the user names. For example, by locating the selection bar  34 A at a position of the user “TOM”, “TOM” is selected. Then, by pressing the “Next” key  33 C at this stage, the selection of “TOM” is confirmed. 
         [0066]    To reprint the file IMG-A.JPG which has been printed in step S 63 , the user selects a user name which has been inputted to the printer  10  in step S 30 . In this case, the user selects the user name “TOM”. After the user name is selected, onscreen representation changes to the second stage screen in  FIG. 12 . In this screen, a list of job names registered in association with the user name “TOM” is displayed. In the example of the onscreen representation of the second stage screen of  FIG. 12 , it is assumed that the job “DOC-B PDF” is also registered in association with the user name “TOM”. 
         [0067]    After the list of the registered job names are displayed, the user is able to select one of the jobs through the touch panel  31 . To reprint the file IMG-A.JPG which has been printed, the user selects the job name which has been inputted to the printer  10  in step S 30 . Therefore, in this case, the user selects the job “IMG-A_JPG”. 
         [0068]    Each time selection of a job is conducted through the selection bar  34 A, the CPU  51  judges whether the selected job belongs to a job of the “Secure-Reprintable” or a job of the “Reprintable” (step S 120 ). If the selected job corresponds to a job of “Secure-Reprintable” (S 120 : YES), control proceeds to step S 130 . If the selected job corresponds to a job of “Reprintable” (S 120 : NO), control proceeds to step S 140 . 
         [0069]    In the example of  FIG. 12 , the job “IMG-A_JPG” has been registered as a job of “Reprintable” in step S 75 . Therefore, the judgment result of step S 120  is “NO”, and control proceeds to step S 140 . In step S 140 , printing of the print target is permitted. Thus, “Print” is displayed on the key  33 C located under right part of the display box  33  as shown in the second stage screen in  FIG. 12 . After the “Print” key  33 C is displayed, the user is able to instruct the printer  10  to print the print target by operating the “Print” key  33 C. 
         [0070]    If the selected job “IMG-A_JPG” belongs to “Secure-Reprintable”, “Next” is displayed on the key  33 C in place of displaying “Print” on the key  33 C. If the instruction to print the print target is inputted to the printer  10  through the “Print” key  33  C, the reprint job registered under the job name “IMG-A_JPG” is read by the CPU  51  from the non-volatile memory  57 . That is, the raster data stored in association with the job name “IMG-A_JPG” is read, and the internal units such as the printer engine  61  is controlled in accordance with the read raster data. 
         [0071]    Thus, the file IMG-A.JPG is printed in step S 140 . After step S 140  is finished, control returns to step S 10 . In this case, control enters the loop process (i.e., the standby state) of steps S 10  and S 100  to wait for user&#39;s access. 
         [0072]    It is understood that step S 40  serves to selectively execute, in accordance with a user operation, a process where consistency between passwords is required as an execution condition and a process where consistency between passwords is not required. 
         [0073]    Hereafter, the case where the “Secure-Reprintable” is selected on the screen shown in  FIG. 8  is described. Similarly to the case where the “Reprintable” is selected, onscreen representation as shown in  FIG. 13  is made on the display box  33  when the “Secure-Reprintable” is selected. In this case, the user inputs a job name and a user name through the touch panel  31 . 
         [0074]    More specifically, when the user selects the item “Secure-Reprintable” on the first stage screen of  FIG. 8 , onscreen representation changes to the first stage screen  431  of  FIG. 13 . Since the job name is displayed on the screen, the user selects a job which will be stored as a secured job in a later stage by pressing the “Next” key  33 C. After the “Next” key  33 C is pressed as described above, the onscreen representation changes to the second stage screen in  FIG. 13 . In this second stage screen, the user is able to input a user name. By pressing the “Next” key  33 C after the user name is inputted, designation of the user name is confirmed. It is understood that the aforementioned steps are substantially equal to those in the case where the “Reprintable” is selected (see  FIG. 9 ). 
         [0075]    After the designation of the user name is confirmed through the “Next” key  33 C, onscreen representation changes from the second stage screen to the third stage screen in  FIG. 13 . In the third stage screen in  FIG. 13 , a password input field  34 B is displayed on the lower side with respect to words “PASSWORD”. In this stage, the user is able to input a password through the ten key  35  on the touch panel  31 .  FIG. 14  shows an example of onscreen representation during the input operation of the password. After the user inputs a password, the user is able to confirm the designation of the password by pressing the “Confirmation” key  33 C located on the lower right part of the last stage screen  444  of  FIG. 14 . 
         [0076]    After the designation of the password is confirmed as described above, onscreen representation changes to the fourth stage screen  434  shown in  FIG. 14 . At this stage, the “Print” key  33 C is displayed in the lower right part of the display box  33 . As described above, if the “Secure-Reprintable” is selected, the “Print” key  33 C is displayed on the display box  33 C only when the input of the job name, the use name and the password is completed. By operating the “Print” key  33 C, the user is able to instruct the printer  10  to execute the printing operation. By completing the above mentioned user operation, the process of step S 30  is finished. 
         [0077]    After the user operation is thus conducted by the user, such user operations are detected by detection means (not shown) in the printer  10  and detected signals are transmitted to the CPU  51 . Thus, the process of the flowchart shown in  FIG. 6  is executed by the CPU  51  while processing various judgment steps according to the user operations. After step S 30  is processed, control proceeds to step S 40  where the CPU  51  judges whether “Secure-Reprintable” is selected. In this case, the judgment result of step S 40  is “YES”. Then, control proceeds to step S 41 . 
         [0078]    Similarly to the case where the “Print Once” or “Reprintable” is selected, the CPU  51  converts the file (i.e., the file IMG-A.JPG) selected as the print target in step S 30  to a bitmap to form raster data (step S 41 ). Then, the CPU  51  drives the print engine  61  in accordance with the raster data to print an image corresponding to the file IMG-A.JPG on a sheet (step S 43 ). That is, the direct printing is conducted. 
         [0079]    After the file IMG-A.JPG is thus printed, control proceeds to step S 51  to start a process for registering a secured job. More specifically, the CPU  51  allocates an area exclusive to the registering in the non-volatile memory  57 , and then writes the job name (i.e., “IMG-A_JPG” which has been inputted by the user in step S 30 ) and the user name (i.e., “TOM”) in the allocated area. Further, in this case, the CPU  51  writes the password in the allocated area (step S 51 ). Then, control proceeds to step S 55 . 
         [0080]    In step S 55 , the raster data of the file (i.e., the file IMG-A.JPG) which has been targeted for the printing in step S 43  is additionally stored in the area allocated at step S 51 . Thus, the raster data of the file of the print target, the job name inputted by the user, the user name and the password are stored as information representing a secured job. If the USB memory  70  is pulled out from the slot  45  afterward, control enters the loop process of steps S 10  and S 100  again. 
         [0081]    As described above, if the “Secure-Reprintable” is selected from the job selection menu, the raster data of the print target (i.e., the file IMG-A.JPG) of the direct print is stored in the printer  10  as a secured job. Therefore, if the “Secure-Reprintable” is selected, it is possible to reprint the file IMG-A.JPG through use of the printer  10  alone (see  FIG. 16 ). 
         [0082]    To execute the reprinting, the user is required to select the reprint mode thorough the mode selection key  38  of the touch panel  31 . If the reprint mode is selected, the judgment result of step S 100  is “YES”. In this case, control proceeds to step S 110 . 
         [0083]    In step S 10 , user names currently registered are displayed in the display box  33  (see the first stage screen  451  of  FIG. 15 ), and the selection bar  34 A is also displayed in the display box  33 . By operating the up and down keys  36 , the selection bar  34 A moves between the displayed user names so that the user can select one of the user names. After the selection is finished, the selection can be confirmed by pressing the “Next” key  33 C. 
         [0084]    To reprint the file IMG-A.JPG which has been printed in step S 43 , the user selects a use&#39;s user name which has been inputted to the printer  10  in step S 30 . In this case, the user selects the user name “TOM”. After the user name is selected, onscreen representation changes to the second stage screen in  FIG. 15 . In this screen, a list of job names registered in association with the user name “TOM” is displayed. 
         [0085]    After the list of the registered job names are displayed, the user is able to select one of the jobs through the touch panel  31 . To reprint the file IMG-A.JPG which has been printed, the user selects the job name which has been inputted to the printer  10  in step S 30 . Therefore, in this case, the user selects the job “IMG-A_JPG”. The job “IMG-A_JPG” belongs to the item “Secure-Reprintable” registered as a secured job in step S 51 . If a job corresponding to a secured job is selected, onscreen representation changes from the second stage screen to the third stage screen in  FIG. 15 . 
         [0086]    In the third stage screen, an input field  34 B is displayed under the words “PASSWORD”. The user is allowed to enter a password to the input field  34 B by operating the ten key  35  of the touch panel  31 . When the user inputs a password, the onscreen representation is switched to ones shown in  FIG. 14 . As described above,  FIG. 14  shows transitions of the onscreen representation during the input operation of the password. By operating the “Confirmation” key  33 C located the lower right portion in the display box  33  on the last stage screen  444  of  FIG. 14 , the inputted password is confirmed. 
         [0087]    Concurrently with the input operation of the password, the CPU  51  executes step S 120 . In step S 120 , the CPU  51  makes a judgment about an attribute of the job selected by the user. Since the job “IMG-A_JPG” for which an attribute is checked is a job registered as a secured job in step S 51 , the judgment result of step S 120  becomes “YES”. Then, control proceeds to step S 130 . 
         [0088]    In step S 130 , the CPU  51  accesses a memory area in which the secured job is registered, and the password of the secured job “IMG-A_JPG” is read from the memory area. Then, the CPU  51  judges whether the password read from the memory area and the password designated in step S 110  match each other. If these passwords match each other, the onscreen representation changes from the state shown in  FIG. 14  to a state shown in the forth stage screen  454  in  FIG. 15 . In this case, the “Print” key  33 C is displayed in a lower right portion of the display box  33  (S 130 : YES). 
         [0089]    After the “Print” key  33 C is thus displayed, the user is able to input a print instruction to the printer  10  to execute the print operation by pressing the “Print” key  33 C. After the print instruction is inputted to the printer  10 , the raster data of the secured job registered under the name “IMG-A_JPG” is read from the non-volatile memory  57 , and the internal units such as the print engine  61  are driven by the CPU  51  in accordance with the raster data. The file IMG-A.JPG is thus reprinted (step S 140 ). 
         [0090]    If the two passwords do not match each other, the judgment result of step S 130  becomes “NO”, and control returns to step S 110 . In this case, the user conducts the menu process (i.e., input of a job name, a user name and a password) again. The CPU  51  judges that the two passwords do not match each other, for example, if the user inputs an incorrect password by mistake. However, in this case, the user is able to re-input a correct password since control returns to step S 110  when such inconsistency between the two passwords is detected in step S 130 . By re-inputting a correct password, the use r is able to reprint the file IMG-A.JPG. 
         [0091]    If the CPU  51  judges that the two passwords do not match each other a plurality of times (e.g., three times), an error process (e.g., a process for informing the user of defective conditions) is executed by the CPU  5   1 . In this case, it is impossible to reprint the file IMG-A.JPG registered as the secured job. 
         [0092]    Hereafter, advantages of the embodiment are described. As described above, by keeping, in the printer  10 , the image (i.e., the raster data) which has been read from the USB memory  70  and has been subjected to the direct printing, the same image can be reprinted using the saved raster data through use of the printer  10  alone. In particular, by keeping the raster data which a resultant of the RIP process, it is possible to reduce time required to complete the reprinting from an instruction of reprint. 
         [0093]    There is a possibility that if raster data is stored in a printer, another user prints the raster data remaining in the printer. In this regard, the printer  10  according to the embodiment is configured to require consistency of passwords. Therefore, according to the embodiment, it is possible to prevent the data remaining in the printer  10  from being printed freely by another user. That is, security of image data can be achieved. 
         [0094]    On the other hand, if consistency of passwords is required, a password input operation becomes a necessary operation. Such a password input operation is troublesome for the user. Further, there is a case where the user thinks that image data to be printed (i.e., to be saved) does not need security. For this reason, in this embodiment, two process items of “Secure-Reprintable” and “Reprintable” are provided. 
         [0095]    If the “Reprintable” is selected, the printer  1   0  does not require consistency of passwords. In this case, the user is not required to input a password. Therefore, the user is allowed to select “Reprintable” for a print target for which security is not needed. Such a configuration makes it possible to print or reprint a print target without conducting troublesome operations. 
         [0096]    In addition, according to the embodiment, the user is allowed to select the process item “Print Once”. By selecting the “Print Once”, the user is able to prevent raster data (e.g., data having a high level of confidentiality) from remaining in the printer  10  although in this case the user is not able to execute the reprinting for the print target of the process item of “Print Once”. 
         [0097]    Since consistency between the two passwords (first authentication information and second authentication information) is required to execute the reprinting, it is possible to limit users capable of executing the reprinting to a first person who has inputted the first authentication information or a second person who is provided the first authentication information from the first person. 
         [0098]    Although the present invention has been described in considerable detail with reference to certain preferred embodiments thereof, other embodiments are possible. 
         [0099]    In the above mentioned embodiment, the printer  10  employs a USB memory as an external storage device. However, it should be noted that the USB memory is one example of an external storage device. Various types of portable storage devices (i.e., removable media) can be employed as an external storage device. 
         [0100]    In the above mentioned embodiment, a printer having only a printing function is used as an image forming device to which the embodiment is applied. However, the embodiment can also be applied to various types of image forming devices such as a multifunction device  200  (a device having a multiple functions of a facsimile function, a scanner function and a printing function) shown in  FIG. 17 . The multifunction device  200  is configured such that a portable storage device (removable media) such as a USB memory can be attached thereto. As shown in  FIG. 17 , the multifunction device  200  includes a main body  210  and an image reading unit  220 . On the front top of the main body  210 , an operation unit  225  is provided. Further, in the front side of the main body  210 , a slot  245  is formed so that the USB memory  70  can be connected to an internal control unit of the multifunction device  200  via the slot  245 . By operating the operation unit  225 , the user is able to display the job selection menu (including “Print Once”, “Reprintable” and “Secure-Reprintable”) and to select a desired job item. 
         [0101]    In the above mentioned embodiment, the raster data is stored in the non-volatile memory  57 . However, a memory to which the raster data is stored is not limited to the non-volatile memory  57 . For example, the raster data may be stored in an internal storage device such as the RAM  55 .