Abstract:
An electronic device in the present disclosure includes the following: an imaging device configured to scan a paper sheet, wherein the paper sheet comprises a first side and a second side, wherein scanning the paper sheet produces an image; a display device; a printing image acquisition unit configured to acquire a printing image; an image forming apparatus configured to print the printing image; and a display control unit configured to control the display device to display, if the produced image includes an image of a paper sheet, a composite image that combines the acquired printing image and the image of the paper sheet within the produced image.

Description:
REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a divisional application of, claims priority to, and incorporates herein by reference the contents of U.S. patent application Ser. No. 14/264,583, filed in the United States Patent and Trademark Office on Apr. 29, 2014, which is based upon and claims priority to the corresponding Japanese Patent Application No. 2013-095360, filed in the Japan Patent Office on Apr. 30, 2013, and Japanese Patent Application No. 2013-136142, filed in the Japan Patent Office on Jun. 28, 2013, the entire contents of which are incorporated herein by reference. 
     
    
     FIELD 
       [0002]    The present disclosure relates to an electronic device that displays a composite image, which combines an image scanned by an imaging device with additional information, on a display device as a print preview. 
       BACKGROUND 
       [0003]    Ina typical print preview, before an image to be printed by an image forming apparatus is actually printed on a paper sheet, a preview of the image to be printed on the paper sheet is artificially displayed. 
         [0004]    In the typical print preview, an appearance of an artificially displayed paper sheet may differ from an appearance of an actual paper sheet when, for example, a color of the artificially displayed paper sheet is a fixed color, such as white, that is different from a color of the actual paper sheet. Accordingly, there is a fear in that an artificial display of the preview of the image to be printed on a paper sheet may differ from the resulting printed image obtained by actually printing the image on a paper sheet. 
       SUMMARY 
       [0005]    An electronic device according to an embodiment of the present disclosure includes: an imaging device; a display device; a printing image acquisition unit; an image forming apparatus; and a display control unit. The imaging device is configured to scan a paper sheet, wherein the paper sheet comprises a first side and a second side, wherein scanning the paper sheet produces an image. The printing image acquisition unit is configured to acquire a printing image. The image forming apparatus is configured to print the printing image. The display control unit is configured to control the display device to display, if the produced image includes an image of a paper sheet, a composite image that combines the acquired printing image and the image of the paper sheet within the produced image. 
         [0006]    A print preview method according to one embodiment of the present disclosure includes: (i) scanning, via an imaging device, a paper sheet, wherein the paper sheet comprises a first side and a second side, wherein scanning the paper sheet produces an image; (ii) acquiring, via a printing image acquisition unit, a printing image; (iii) printing, via an image forming apparatus, the printing image; and (iv) controlling, via a display control unit, a display device to display, if the produced image includes an image of a paper sheet, a composite image in which the acquired printing image and the image of the paper sheet included in the produced image are combined. 
         [0007]    A non-transitory computer-readable recording medium according to one embodiment of the present disclosure has stored a print preview program executable by a computer of an electronic device. The print preview program includes: a first program code for causing the computer to scan a paper sheet, wherein the paper sheet comprises a first side and a second side, wherein scanning the paper sheet produces an image; a second program code for causing the computer to acquire a printing image; a third program code for causing the computer to print the printing image; and a fourth program code for causing the computer to control a display device to display, if the produced image includes an image of a paper sheet, a composite image in which the acquired printing image and an image of the paper sheet included in the produced image are combined. 
         [0008]    Additional features and advantages are described herein, and will be apparent from the following detailed description and the figures. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    All drawings are intended to illustrate some aspects and examples of the present disclosure. The drawings described are only schematic and are non-limiting, and are not necessarily drawn to scale. 
           [0010]      FIG. 1  illustrates a configuration of an image forming system according to an embodiment of the present disclosure. 
           [0011]      FIG. 2  illustrates a configuration of an MFP illustrated in  FIG. 1 . 
           [0012]      FIG. 3  illustrates a configuration of a mobile device illustrated in  FIG. 1 . 
           [0013]      FIG. 4  illustrates an operation of the mobile device illustrated in  FIG. 3  performed when a preview image is displayed. 
           [0014]      FIG. 5  illustrates an example of a head position of a paper sheet within a scanned image displayed on a display unit illustrated in  FIG. 3 . 
           [0015]      FIG. 6  illustrates an example of a preview image displayed on the display unit illustrated in  FIG. 3 . 
           [0016]      FIG. 7  illustrates another example of the preview image displayed on the display unit illustrated in  FIG. 3 . 
           [0017]      FIG. 8  illustrates another example of the preview image displayed on the display unit illustrated in  FIG. 3 . 
           [0018]      FIG. 9  illustrates another example of the preview image displayed on the display unit illustrated in  FIG. 3 . 
           [0019]      FIG. 10  illustrates another example of the preview image displayed on the display unit illustrated in  FIG. 3 . 
           [0020]      FIG. 11  illustrates a configuration of an image forming system according to another embodiment of the present disclosure. 
           [0021]      FIG. 12  illustrates a configuration of a mobile device illustrated in  FIG. 11 . 
           [0022]      FIG. 13  illustrates an operation of the mobile device illustrated in  FIG. 12  performed when a binding orientation is set for double-sided printing performed on the MFP. 
           [0023]      FIG. 14  illustrates an operation continued from  FIG. 13 . 
           [0024]      FIG. 15  illustrates another operation continued from  FIG. 13 . 
           [0025]      FIG. 16  illustrates composite image displaying processing in the operations illustrated in  FIG. 13  to  FIG. 15 . 
           [0026]      FIG. 17  illustrates an example of a preview image displayed on a display unit illustrated in  FIG. 12 . 
           [0027]      FIG. 18  illustrates another example of the preview image displayed on the display unit illustrated in  FIG. 12 . 
           [0028]      FIG. 19  illustrates another example of the preview image displayed on the display unit illustrated in  FIG. 12 . 
           [0029]      FIG. 20A  illustrates an example of the preview image displayed on the display unit when the binding orientation is set to “left bind”. 
           [0030]      FIG. 20B  illustrates an example of the preview image displayed on the display unit when the binding orientation is set to “top bind”. 
       
    
    
     DETAILED DESCRIPTION 
       [0031]    Various embodiments are described below with reference to the figures. It should be understood, however, that numerous variations from the depicted arrangements and functions are possible while remaining within the scope and spirit of the claims. For instance, one or more elements may be added, removed, combined, distributed, substituted, re-positioned, re-ordered, and/or otherwise changed. Further, where this description refers to one or more functions being implemented on and/or by one or more devices, one or more machines, and/or one or more networks, it should be understood that one or more of such entities could carry out one or more of such functions by themselves or in cooperation, and may do so by application of any suitable combination of hardware, firmware, and/or software. For instance, one or more processors may execute one or more sets of programming instructions as at least part of carrying out one or more of the functions described herein. 
         [0032]    An embodiment of the present disclosure is described with reference to the accompanying drawings. 
         [0033]      FIG. 1  illustrates a configuration of an image forming system  10  according to the embodiment. 
         [0034]    As illustrated in  FIG. 1 , the image forming system  10  includes a plurality of multifunction peripherals (MFPs) including an MFP  20 , a management server  30  such as a personal computer (PC) that manages the plurality of MFPs, and a mobile device  40  such as a smartphone. The plurality of MFPs, the management server  30 , and the mobile device  40  of the image forming system  10  are communicably connected to one another through a network  11  such as a local area network (LAN) or the Internet. The mobile device  40  constitutes an electronic device according to the present disclosure. 
         [0035]    The configuration of each of the MFPs of the image forming system  10  is the same as the configuration of the MFP  20 . Therefore, the MFP  20  is described below as a representative of the plurality of MFPs of the image forming system  10 . 
         [0036]      FIG. 2  illustrates the configuration of the MFP  20 . 
         [0037]    As illustrated in  FIG. 2 , the MFP  20  includes an operation unit  21  serving as an input device such as buttons through which various operations are input by a user, a display unit  22  serving as a display device such as a liquid crystal display (LCD) that displays various kinds of information, a scanner  23  that reads an image from an original document, a printer  24  that executes printing on a paper sheet such as printing paper, a FAX communication unit  25  that performs FAX communications to and/or from an external facsimile machine (not shown) through a communication line such as a public telephone line, a network communication unit  26  that communicates to and/or from an external apparatus through the network  11  illustrated in  FIG. 1 , a storage unit  27  including a nonvolatile storage device such as an electrically erasable programmable read only memory (EEPROM) or a hard disk drive (HDD) that stores various kinds of data, and a control unit  28  that controls the entire MFP  20 . 
         [0038]    The operation unit  21  may include an input device including a touch panel together with the display unit  22 . 
         [0039]    The control unit  28  includes, for example, a central processing unit (CPU), a read only memory (ROM) that stores programs and various kinds of data, and a random access memory (RAM) used as a work area for the CPU. The CPU executes a program stored in the ROM or the storage unit  27 . 
         [0040]      FIG. 3  illustrates a configuration of the mobile device  40 . 
         [0041]    As illustrated in  FIG. 3 , the mobile device  40  includes an operation unit  41  serving as an input device with, for example, buttons through which various operations are input, a display unit  42  serving as a display device such as an LCD that displays various kinds of information, an imaging unit  43  serving as an imaging device that photographs a still image or a moving image, a network communication unit  44  that communicates to and/or from an external apparatus through the network  11  illustrated in  FIG. 1 , a storage unit  45  including a nonvolatile storage device such as an HDD that stores programs and various kinds of data, and a control unit  46  that controls the entire mobile device  40 . 
         [0042]    The operation unit  41  may include an input device including a touch panel together with the display unit  42 . 
         [0043]    The storage unit  45  stores a print preview program  45   a  executed by the control unit  46 . 
         [0044]    The control unit  46  includes, for example, a CPU, a ROM that stores programs and various kinds of data, and a RAM used as a work area for the CPU. The CPU executes a program stored in the ROM or the storage unit  45 . 
         [0045]    The control unit  46  executes the print preview program  45   a  stored in the storage unit  45 , to thereby function as a printing image acquisition unit  46   a , a display control unit  46   b , and an apparatus designation reception unit  46   c . The printing image acquisition unit  46   a  acquires a printing image to be printed on the paper sheet by the MFP. The display control unit  46   b  controls the display unit  42  to display, when a paper sheet is included in an image scanned by the imaging unit  43 , a composite image that combines the printing image acquired by the printing image acquisition unit  46   a  on the paper sheet within the scanned image. The apparatus designation reception unit  46   c  receives a designation of the MFP to be used for printing the printing image. 
         [0046]    Next, a description is made of an operation of the image forming system  10 . 
         [0047]    First, a description is made of the operation of the image forming system  10  performed when the printing image is generated by reading an image from an original document. 
         [0048]    In response to an instruction issued through the operation unit  21 , the control unit  28  of the MFP  20  reads an image from an original document by the scanner  23  to generate a printing image, and transmits the generated printing image to the management server  30  through the network communication unit  26 . 
         [0049]    Therefore, the management server  30  receives and stores the printing image transmitted from the MFP  20 . 
         [0050]    Next, a description is made of an operation of the mobile device  40  performed when a preview image is displayed. 
         [0051]    The user of the mobile device  40  may activate the print preview program  45   a  when it is desired to display the preview image on the mobile device  40 , to thereby cause the control unit  46  of the mobile device  40  to execute an operation illustrated in  FIG. 4 . 
         [0052]      FIG. 4  illustrates the operation of the mobile device  40  performed when the preview image is displayed. 
         [0053]    As illustrated in  FIG. 4 , the printing image acquisition unit  46   a  of the mobile device  40  acquires the printing image to be printed on the paper sheet by the MFP through the network communication unit  44  (Step S 101 ). The printing image acquisition unit  46   a  may acquire from the management server  30  the printing image generated from the original document by the MFP and stored by the management server  30 , or may acquire a printing image other than the printing image generated from the original document by the MFP and stored by the management server  30 . For example, the printing image acquisition unit  46   a  may acquire a printing image generated from the original document by the MFP  20  and transmitted directly from the MFP  20  to the mobile device  40 , or may acquire a printing image generated by a PC (not shown) and transmitted to the mobile device  40 . 
         [0054]    Subsequently, the apparatus designation reception unit  46   c  of the mobile device  40  displays on the display unit  42  an MFP designation screen used for receiving a designation of the MFP to be used for print the printing image, to thereby receive the designation of the MFP through the operation unit  41  (Step S 102 ). 
         [0055]    Subsequently, the display control unit  46   b  of the mobile device  40  displays the image scanned by the imaging unit  43  on the display unit  42  (Step S 103 ). Note that an image that is “scanned” may be photographed, scanned, imaged, picked up, or otherwise read in by any suitable scanner, imaging device, imaging unit, or the like. 
         [0056]    Subsequently, the display control unit  46   b  determines whether or not the paper sheet is included in the scanned image until the display control unit  46   b  determines that the paper sheet is included in the scanned image (Step S 104 ). Here, the display control unit  46   b  recognizes the paper sheet itself within the scanned image by an image recognition technology, to thereby recognize that the paper sheet is included in the scanned image. Note that, the user of the mobile device  40  can include the paper sheet in the scanned image by adjusting a position and an orientation of the mobile device  40  so that the paper sheet is included in the scanned image displayed on the display unit  42 . 
         [0057]    When the display control unit  46   b  determines in Step S 104  that the paper sheet is included in the scanned image, the display control unit  46   b  determines whether or not a head position of the paper sheet within the scanned image has been designated (Step S 105 ). The user of the mobile device  40  can designate the head position by setting the head position of the paper sheet within the scanned image displayed on the display unit  42  through the operation unit  41 . 
         [0058]      FIG. 5  illustrates an example of the head position of the paper sheet within the scanned image displayed on the display unit  42 . 
         [0059]    In  FIG. 5 , a scanned image  50  displayed on the display unit  42  includes a paper sheet  51 . In the paper sheet  51  within the scanned image  50 , a head position  60  designated by the user is indicated by being highlighted by a thick line. 
         [0060]    As illustrated in  FIG. 4 , when determining in Step S 105  that the head position has not been designated, the display control unit  46   b  returns to the processing of Step S 104  again. 
         [0061]    When the display control unit  46   b  determines in Step S 105  that the head position has been designated, the display control unit  46   b  acquires a size of the paper sheet within the scanned image with reference to the head position designated in Step S 105  (Step S 106 ). Specifically, the display control unit  46   b  acquires a vertical length of the paper sheet within the scanned image and a horizontal length of the paper sheet within the scanned image. 
         [0062]    Subsequently, the display control unit  46   b  calculates the size of the printing image within the scanned image based on the size acquired in Step S 106  and a magnification of the printing image used when the printing image is printed on the paper sheet (hereinafter referred to as “printing magnification”) (Step S 107 ). For example, in a case where the vertical length and the horizontal length of the paper sheet within the scanned image are 52 and 37, respectively, the display control unit  46   b  calculates a vertical length and a horizontal length of the printing image within the scanned image as 52 and 37, respectively, when the printing magnification is 1, and calculates the vertical length and the horizontal length of the printing image within the scanned image as 104 and 74, respectively, when the printing magnification is 2. Note that, an initial value of the printing magnification is, for example, “1”. 
         [0063]    Subsequently, the display control unit  46   b  generates the printing image for a preview image (hereinafter referred to as “preview of the printing image”) with the size calculated in Step S 107  based on the printing image acquired in Step S 101  and the size calculated in Step S 107  (Step S 108 ). Here, the display control unit  46   b  changes an appearance of the preview of the printing image based on an output characteristic of the MFP received in Step S 102 . For example, when the MFP received in Step S 102  is a dedicated monochrome machine, the display control unit  46   b  changes the preview of the printing image to a monochrome image. Further, even when the MFP received in Step S 102  is a color machine, the display control unit  46   b  may change the preview of the printing image based on color reproducibility of the MFP. 
         [0064]    Subsequently, the display control unit  46   b  generates a composite image that combines the preview of the printing image generated in Step S 108  with the scanned image, in a position corresponding in the paper sheet within the scanned image to the position of an origin of the printing image with respect to the paper sheet used when the printing image is printed on the paper sheet (hereinafter referred to as “printing position”) (Step S 109 ). Note that, an initial value of the printing position is, for example, the position of a left end of a top edge of the paper sheet when viewed with the head position placed at the top. 
         [0065]    Subsequently, the display control unit  46   b  displays the composite image generated in Step S 109 , in other words, the preview image on the display unit  42  (Step S 110 ). In other words, for example, the display control unit  46   b  displays such a preview image as illustrated in  FIG. 6  on the display unit  42  by an augmented reality (AR) technology. 
         [0066]    A preview image  70  as illustrated in  FIG. 6  is a composite image that combines a preview of the printing image  71  with the scanned image  50 . 
         [0067]    As illustrated in  FIG. 4 , the display control unit  46   b  determines whether or not the magnification of the preview of the printing image has been changed through the operation unit  41  after the processing of Step S 110  (Step S 111 ). For example, the user of the mobile device  40  can change the magnification of the preview of the printing image by directly operating the preview of the printing image displayed on the display unit  42  through the operation unit  41 , and can also change the magnification of the preview of the printing image by specifically designating a numerical value indicating the magnification through the operation unit  41 . 
         [0068]    When the display control unit  46   b  determines in Step S 111  that the magnification of the preview of the printing image has not been changed, the display control unit  46   b  determines whether or not the position of the preview of the printing image with respect to the paper sheet within the scanned image has been changed through the operation unit  41  (Step S 112 ). For example, the user of the mobile device  40  can change the position of the preview of the printing image by directly operating the preview of the printing image displayed on the display unit  42  through the operation unit  41 , and can also change the position of the preview of the printing image by specifically designating a numerical value indicating the position through the operation unit  41 . 
         [0069]    When the display control unit  46   b  determines in Step S 112  that the position of the preview of the printing image with respect to the paper sheet within the scanned image has not been changed, the display control unit  46   b  returns to the processing of Step S 104  again. 
         [0070]    When the display control unit  46   b  determines in Step S 111  that the magnification of the preview of the printing image has been changed, the display control unit  46   b  changes the printing magnification based on the change in the magnification of the preview of the printing image (Step S 113 ), and returns to the processing of Step S 104  again. In other words, the display control unit  46   b  displays, for example, such a preview image as illustrated in  FIG. 7  on the display unit  42  by the AR technology. 
         [0071]    In the preview image  70  illustrated in  FIG. 7 , the preview of the printing image  71  has a size of ½ of that of the preview image  70  illustrated in  FIG. 6 . In other words, in a state illustrated in  FIG. 7 , the printing magnification is set to ½. 
         [0072]    As illustrated in  FIG. 4 , when determining in Step S 112  that the position of the preview of the printing image with respect to the paper sheet within the scanned image has been changed, the display control unit  46   b  changes the printing position based on the change in the position of the preview of the printing image (Step S 114 ), and returns to the processing of Step S 104  again. In other words, the display control unit  46   b  displays, for example, such a preview image as illustrated in  FIG. 8  on the display unit  42  by the AR technology. 
         [0073]    In the preview image  70  illustrated in  FIG. 8 , the position of the preview of the printing image  71  with respect to the paper sheet  51  within the scanned image  50  differs from that of the preview image  70  illustrated in  FIG. 7 . 
         [0074]    Note that, in the above description, the vertical and horizontal orientations of the paper sheet within the scanned image are the same as the vertical and horizontal orientations of the scanned image, but, as illustrated in  FIG. 9 , the vertical and horizontal orientations of the paper sheet within the scanned image may differ from the vertical and horizontal orientations of the scanned image. 
         [0075]    Further, even when a shape of the paper sheet within the scanned image has changed from a rectangle, the display control unit  46   b  may change the shape of the printing image within the composite image based on the change. For example, even when the shape of the paper sheet within the scanned image has changed to the shape illustrated in  FIG. 10 , the display control unit  46   b  can change the shape of the printing image within the composite image based on the shape of the paper sheet within the scanned image as illustrated in  FIG. 10 . According to this configuration, the mobile device  40  can allow the user to confirm not only the preview image viewed from the front of the paper sheet but also the preview image viewed from various angles with respect to the paper sheet by being changed in a photographing angle of the imaging unit  43  with respect to the paper sheet. 
         [0076]    Note that, the above description is directed to the processing performed when the size of the printing image is the same as the size of the paper sheet on which the printing image is to be printed. The display control unit  46   b  can acquire the size of the printing image from the printing image itself, and can therefore generate, even when the size of the printing image differs from the size of the paper sheet, the preview of the printing image to have a suitable size based on the size of the printing image and the size of the paper sheet in a manner that the size of the paper sheet is specifically designated through the operation unit  41 . 
         [0077]    Next, a description is made of an operation of the image forming system  10  performed when the MFP is used for printing the printing image. 
         [0078]    When being instructed to perform printing on the paper sheet based on the preview image displayed on the display unit  42  through the operation unit  41 , the control unit  46  of the mobile device  40  transmits the printing image acquired in Step S 101  to the MFP received in Step S 102  along with the printing magnification and the printing position through the network communication unit  44 . 
         [0079]    Therefore, the control unit of the MFP prints the printing image transmitted from the mobile device  40  on the paper sheet by a printer by using the printing magnification and the printing position transmitted from the mobile device  40  along with the printing image. 
         [0080]    As described above, the mobile device  40  displays the composite image that combines the printing image on the paper sheet within the image scanned by the imaging unit  43 , on the display unit  42  as the preview image (Step S 110 ), and hence an appearance of actual paper sheet can be reflected on the preview image, with the result that the preview image similar to an actual resulting printed image can be generated. 
         [0081]    The mobile device  40  recognizes the paper sheet itself within the scanned image by the image recognition technology, to thereby recognize that the paper sheet is included in the scanned image (Step S 104 ), and hence the composite image that combines the printing image on the paper sheet within the scanned image, can be displayed on the display unit  42  as the preview image even when a special marker used for recognizing that the paper sheet is included in the scanned image is not formed on the paper sheet. 
         [0082]    Note that, the mobile device  40  may be configured to recognize that the paper sheet is included in the scanned image by reading the special marker used for recognizing that the paper sheet is included in the scanned image from above the paper sheet. 
         [0083]    The mobile device  40  changes the appearance of the printing image within the composite image based on the output characteristic of the MFP by receiving the designation of the MFP that is to print the printing image on the paper sheet, and hence the preview image suitable for the MFP used for printing the printing image can be easily displayed on the display device. 
         [0084]    Note that, the image forming system  10  includes a mobile device as the electronic device according to the embodiment of the present disclosure, but may include another electronic device such as a PC or the like instead of the mobile device. 
         [0085]    Further, the image forming system  10  includes an MFP as the image forming apparatus according to the embodiment of the present disclosure, but the image forming system  10  may include another image forming apparatus such as a dedicated printer, a dedicated copier, a dedicated facsimile device, or the like instead of the MFP. 
         [0086]    Now, another embodiment of the present disclosure is described with reference to the accompanying drawings. 
         [0087]      FIG. 11  illustrates a configuration of an image forming system  110  according to the embodiment. 
         [0088]    As illustrated in  FIG. 11 , the image forming system  110  includes a plurality of multifunction peripherals (MFPs) including a MFP  20 , a management server  30  such as a personal computer (PC) that manages the plurality of MFPs, and a mobile device  140  such as a smartphone. The plurality of MFPs, the management server  30 , and the mobile device  140  of the image forming system  110  are communicably connected to one another through a network  11  such as a local area network (LAN) or the Internet. The mobile device  140  constitutes an electronic device according to the present disclosure. 
         [0089]    As described above, the MFP  20  has the configuration illustrated in  FIG. 2 . The configuration of each of the plurality of MFPs of the image forming system  110  is the same as the configuration of the MFP  20 . Therefore, the MFP  20  is described below as a representative of the plurality of MFPs of the image forming system  110 . 
         [0090]      FIG. 12  illustrates a configuration of the mobile device  140 . 
         [0091]    As illustrated in  FIG. 12 , the mobile device  140  includes an operation unit  141  serving as an input device with, for example, buttons through which various operations are input, a display unit  142  serving as a display device such as an LCD that displays various kinds of information, an imaging unit  143  serving as an imaging device that photographs a still image or a moving image, a network communication unit  144  that communicates to and/or from an external apparatus through the network  11  illustrated in  FIG. 11 , a storage unit  145  including a nonvolatile storage device such as an HDD that stores programs and various kinds of data, and a control unit  146  that controls the entire mobile device  140 . 
         [0092]    The operation unit  141  may include an input device including a touch panel together with the display unit  142 . 
         [0093]    The storage unit  145  stores a print preview program  145   a  executed by the control unit  146 . The print preview program  145   a  may be installed on the mobile device  140  at a manufacturing stage of the mobile device  140 , may be installed on the mobile device  140  additionally from a storage medium such as a universal serial bus (USB) memory, or may be installed on the mobile device  140  additionally through the network  11 . 
         [0094]    The control unit  146  includes, for example, a CPU, a ROM that stores programs and various kinds of data, and a RAM used as a work area for the CPU. The CPU executes a program stored in the ROM or the storage unit  145 . 
         [0095]    The control unit  146  executes the print preview program  145   a  stored in the storage unit  145 , to thereby function as a rotational direction detection unit  146   a , a binding orientation setting unit  146   b , a display control unit  146   c , and a printing image acquisition unit  146   d . The rotational direction detection unit  146   a  detects, when the paper sheet is turned over, a rotational direction of the turning-over with respect to the paper sheet. The binding orientation setting unit  146   b  sets a binding orientation for double-sided printing performed on the MFP. The display control unit  146   c  displays the image scanned by the imaging unit  143  on the display unit  142 . The printing image acquisition unit  146   d  acquires the printing image to be printed by the MFP. 
         [0096]    Next, a description is made of an operation of the image forming system  110 . 
         [0097]    First, a description is made of the operation of the image forming system  110  performed when the binding orientation is set for the double-sided printing by reading images from a plurality of pages of original documents. 
         [0098]    In response to an instruction issued through the operation unit  21 , the control unit  28  of the MFP  20  reads images from a plurality of pages of original documents by the scanner  23  to generate a plurality of pages of printing images, and transmits the generated plurality of pages of printing images to the management server  30  through the network communication unit  26 . 
         [0099]    Therefore, the management server  30  receives and stores the plurality of pages of printing images transmitted from the MFP  20 . 
         [0100]    Next, a description is made of an operation of the mobile device  140  performed when the binding orientation is set for the double-sided printing performed on the MFP. 
         [0101]    The user of the mobile device  140  may activate the print preview program  145   a  when it is desired to set the binding orientation for the double-sided printing performed on the MFP, to thereby cause the control unit  146  of the mobile device  140  to execute operations illustrated in  FIG. 13  to  FIG. 15 . 
         [0102]      FIG. 13  illustrates an operation of the mobile device  140  performed when the binding orientation is set for the double-sided printing performed on the MFP.  FIG. 14  illustrates an operation of the mobile device  140  continued from  FIG. 13 .  FIG. 15  illustrates an operation of the mobile device  140  continued from  FIG. 13  that is different from the operation illustrated in  FIG. 14 . 
         [0103]    As illustrated in  FIG. 13  to  FIG. 15 , the printing image acquisition unit  146   d  of the mobile device  140  acquires a plurality of pages of printing images to be printed on the paper sheet by the MFP through the network communication unit  144  (Step S 1101 ). Here, the printing image acquisition unit  146   d  may acquire from the management server  30  a plurality of pages of printing images generated from a plurality of pages of original documents by the MFP and stored by the management server  30 , or may acquire a plurality of pages of printing images of another kind. For example, the printing image acquisition unit  146   d  may acquire a plurality of pages of printing images generated from a plurality of pages of original documents by the MFP  20  and transmitted directly from the MFP  20  to the mobile device  140 , or may acquire a plurality of pages of printing images generated by the PC (not shown) and transmitted to the mobile device  140 . 
         [0104]    Subsequently, the control unit  146  of the mobile device  140  displays on the display unit  142  the MFP designation screen used for receiving the designation of the MFP to be used for printing the printing images, to thereby receive the designation of the MFP through the operation unit  141  (Step S 1102 ). 
         [0105]    Subsequently, the display control unit  146   c  of the mobile device  140  displays the image scanned by the imaging unit  143  on the display unit  142  (Step S 1103 ). 
         [0106]    Subsequently, the display control unit  146   c  determines whether or not the paper sheet is included in the scanned image until the display control unit  146   b  determines that the paper sheet is included in the scanned image (Step S 1104 ). Here, the display control unit  146   c  recognizes the paper sheet itself within the scanned image by the image recognition technology, to thereby recognize that the paper sheet is included in the scanned image. Note that, the user of the mobile device  140  can include the paper sheet in the scanned image by adjusting the position and the orientation of the mobile device  140  so that the paper sheet is included in the scanned image displayed on the display unit  142 . 
         [0107]    When the display control unit  146   b  determines in Step S 1104  that the paper sheet is included in the scanned image, the display control unit  146   c  determines whether or not the head position of the paper sheet within the scanned image has been designated (Step S 1105 ). The user of the mobile device  140  can designate the head position by setting the head position of the paper sheet within such a scanned image as illustrated in  FIG. 5  displayed on the display unit  142  through the operation unit  141 . 
         [0108]    As illustrated in  FIG. 13  to  FIG. 15 , the display control unit  146   c  executes the processing of Step S 1104  when determining in Step S 1105  that the head position has not been designated. 
         [0109]    When the display control unit  146   b  determines in Step S 1105  that the head position has been designated, the display control unit  146   c  sets, as a target, the printing image on the first page among the plurality of pages of printing images acquired in Step S 1101  (Step S 1106 ). 
         [0110]    Subsequently, the display control unit  146   c  executes composite image displaying processing illustrated in  FIG. 16  (Step S 1107 ). 
         [0111]      FIG. 16  illustrates the composite image displaying processing included in the operations illustrated in  FIG. 13  to  FIG. 15 . 
         [0112]    As illustrated in  FIG. 16 , the display control unit  146   c  acquires the size of the paper sheet within the scanned image with reference to the designated head position (Step S 1201 ). Specifically, the display control unit  146   c  acquires the vertical length (length of the left side or the right side of the paper sheet when viewed with the head position placed at the top) of the paper sheet within the scanned image and the horizontal length (length of the top side or the bottom side when viewed with the head position placed at the top) of the paper sheet within the scanned image. 
         [0113]    Subsequently, the display control unit  146   c  generates a printing image for a preview image (hereinafter referred to as “preview of the printing image”) with the size acquired in Step S 1201  for the printing image of a target page based on the printing image of the target page and the size acquired in Step S 1201  (Step S 1202 ). Here, the display control unit  146   c  changes the appearance of the preview of the printing image based on the output characteristic of the MFP received in Step S 1102 . For example, when the MFP received in Step S 1102  is a dedicated monochrome machine, the display control unit  146   c  changes the preview of the printing image to a monochrome image. Further, even when the MFP received in Step S 1102  is a color machine, the display control unit  146   c  may change the preview of the printing image based on the color reproducibility of the MFP. 
         [0114]    Subsequently, the display control unit  146   c  generates a composite image that combines the preview of the printing image generated in Step S 1202  with the scanned image (Step S 1203 ). At this time, the display control unit  146   c  generates the composite image by combining the preview of the printing image in a specific position in the paper sheet within the scanned image. Here, the specific position in the paper sheet within the scanned image corresponds to a position of a reference point for placement of the printing image with respect to the paper sheet used when the printing image is printed on the paper sheet. The position of the reference point for the placement of the printing image with respect to the paper sheet is, for example, the position of the left end of the top edge of the paper sheet when viewed with the head position placed at the top. At this time, the specific position in the paper sheet within the scanned image is the position of the left end of the top edge of the paper sheet within the scanned image when viewed with the head position placed at the top. 
         [0115]    Subsequently, the display control unit  146   c  displays the composite image generated in Step S 1203 . In other words, the display control unit  146   c  displays the preview image on the display unit  142  (Step S 1204 ) and brings the composite image displaying processing illustrated in  FIG. 16  to an end. In other words, for example, the display control unit  146   c  displays such a preview image as illustrated in  FIG. 17  on the display unit  142  by the AR technology. 
         [0116]    The preview image  70  illustrated in  FIG. 17  is the composite image that combines the preview of the printing image  71  with the scanned image  50 . The preview image  70  is an example of the composite image generated by combining the preview of the printing image  71  with the scanned image  50  with the left end of the top edge of the preview of the printing image  71  coinciding with the left end of the top edge of the paper sheet  51  within the scanned image  50  when viewed with the head position  60  placed at the top in a case where the position of the reference point for the placement of the printing image with respect to the paper sheet is the left end of the top edge of the paper sheet. 
         [0117]    In the above description, the vertical and horizontal orientations of the paper sheet  51  within the scanned image  50  are the same as the vertical and horizontal orientations of the scanned image  50 , but, as illustrated in  FIG. 18 , the vertical and horizontal orientations of the paper sheet  51  within the scanned image  50  may differ from the vertical and horizontal orientations of the scanned image  50 . Even at this time, the display control unit  146   c  acquires the vertical and horizontal sizes of the paper sheet  51  within the scanned image  50  with reference to the designated head position  60 , and generates the composite image by combining the preview of the printing image  71  in the specific position in the paper sheet  51  within the scanned image  50 . 
         [0118]    Further, even when the shape of the paper sheet  51  within the scanned image  50  has changed from a rectangle due to an influence of the photographing position, the display control unit  146   c  may change the shape of the preview of the printing image within the composite image based on the change. For example, even when the shape of the paper sheet  51  within the scanned image  50  has changed to the shape illustrated in  FIG. 19 , the display control unit  146   c  can change the shape of the preview of the printing image within the composite image based on the shape of the paper sheet  51  within the scanned image  50  as illustrated in  FIG. 19 . At this time, the display control unit  146   c  acquires the lengths of the top side, the bottom side, the left side, and the right side of the paper sheet  51  within the scanned image  50  when viewed with the head position  60  placed at the top in Step S 1201  illustrated in  FIG. 16 , and changes the shape of the preview of the printing image  71  based on a ratio of the lengths of the respective sides. 
         [0119]    According to this configuration, the mobile device  140  can allow the user to confirm not only the preview image  70  viewed from the front of the paper sheet but also the preview image  70  viewed from various angles with respect to the paper sheet by being changed in the photographing angle of the imaging unit  143  with respect to the paper sheet. 
         [0120]    Note that, the above description is directed to the processing performed when the size of the printing image is the same as the size of the paper sheet on which the printing image is to be printed. The display control unit  146   c  can acquire the size of the printing image from the printing image itself. Accordingly, even when the size of the printing image differs from the size of the paper sheet, the display control unit  146   c  can generate the preview of the printing image to have a suitable size based on the size of the printing image and the size of the paper sheet in a manner that the size of the paper sheet is specifically designated through the operation unit  141 . 
         [0121]    As illustrated in  FIG. 13  to  FIG. 15 , the control unit  146  determines whether or not the double-sided printing has been designated after the processing of Step S 1107  (Step S 1108 ). The user of the mobile device  140  can designate the double-sided printing through the operation unit  141 . 
         [0122]    When the control unit  146  determines in Step S 1108  that the double-sided printing has not been designated, the control unit  146  executes the processing of Step S 1104 . 
         [0123]    When the control unit  146  determines in Step S 1108  that the double-sided printing has been designated, the control unit  146  sets the double-sided printing (Step S 1109 ). 
         [0124]    Subsequently, the display control unit  146   c  determines whether or not the paper sheet is included in the image scanned by the imaging unit  143  (Step S 1110 ). 
         [0125]    When the control unit  146  determines in Step S 1110  that the paper sheet is not included in the scanned image, the control unit  146  cancels the setting of the double-sided printing (Step S 1111 ). 
         [0126]    Subsequently, the display control unit  146   c  executes the processing of Step S 1104 . 
         [0127]    When the rotational direction detection unit  146   a  of the control unit  146  determines in Step S 1110  that the paper sheet is included in the scanned image, the rotational direction detection unit  146   a  determines whether or not the paper sheet included in the scanned image has been turned over based on image processing for the scanned image (Step S 1112 ). The user of the mobile device  140  can, for example, turn over the paper sheet by manually reversing the paper sheet with his/her hand. 
         [0128]    When the rotational direction detection unit  146   a  determines in Step S 1112  that the paper sheet has not been turned over, the display control unit  146   c  executes the processing of Step S 1110 . 
         [0129]    When the rotational direction detection unit  146   a  determines in Step S 1112  that the paper sheet has been turned over, the rotational direction detection unit  146   a  detects the rotational direction of the turning-over with respect to the paper sheet included in the scanned image based on the image processing for the scanned image (Step S 1113 ). 
         [0130]    Subsequently, the binding orientation setting unit  146   b  of the control unit  146  sets the binding orientation for the double-sided printing performed on the MFP based on the rotational direction detected in Step S 1113  (Step S 1114 ). For example, the binding orientation setting unit  146   b  (i) sets the binding orientation to “top bind” when the rotational direction detected in Step S 1113  is a rotational direction for turning over the paper sheet about a top edge of the paper sheet, (ii) sets the binding orientation to “bottom bind” when the rotational direction detected in Step S 1113  is a rotational direction for turning over the paper sheet about a bottom edge of the paper sheet, (iii) sets the binding orientation to “left bind” when the rotational direction detected in Step S 1113  is a rotational direction for turning over the paper sheet about a left edge of the paper sheet, and (iv) sets the binding orientation to “right bind” when the rotational direction detected in Step S 1113  is a rotational direction for turning over the paper sheet about a right edge of the paper sheet. 
         [0131]    Subsequently, the display control unit  146   c  sets as the target the printing image on the page next to the current target page among the plurality of pages of printing images acquired in Step S 1101  (Step S 1115 ). 
         [0132]    Subsequently, the display control unit  146   c  executes the composite image displaying processing illustrated in  FIG. 16  (Step S 1116 ). 
         [0133]    The preview image  70  displayed on the display unit  142  in Step S 1116  is, for example, an image illustrated in  FIG. 20A  and  FIG. 20B .  FIG. 20A  illustrates an example of the preview image  70  of the next page obtained when the binding orientation is set to “left bind”. As illustrated in  FIG. 20A , the preview of the printing image  71  is displayed by being combined with the paper sheet  51  within the scanned image  50  when viewed with the head position  60  placed at the top. At this time, an apparent binding position is the right edge of the paper sheet  51 .  FIG. 20B  illustrates an example of the preview image  70  of the next page obtained when the binding orientation is set to “top bind”. As illustrated in  FIG. 20B , the preview of the printing image  71  is displayed by being combined with the paper sheet  51  within the scanned image  50  when viewed with the head position  60  of the previous page placed at the bottom. The head position  60  of the previous page is displayed at the top of the paper sheet  51  in the preview image of the previous page, but after the actual paper sheet is turned over about the top edge, displayed at the bottom of the paper sheet  51  in the preview image  70  of the next page. In  FIG. 20B , the apparent binding position is the bottom edge of the paper sheet  51 . The head position  60  illustrated in each of  FIG. 20A  and  FIG. 20B  is the designated head position, and is the head position of the previous page. 
         [0134]    As illustrated in  FIG. 13  to  FIG. 15 , the control unit  146  determines after Step S 1116  whether or not all the plurality of pages of printing images acquired in Step S 1101  have been set as the target (Step S 1117 ). 
         [0135]    When the control unit  146  determines in Step S 1117  that not all the pages have been set as the target, in other words, when there exists a page that has not yet been set as the target, the display control unit  146   c  determines whether or not the paper sheet is included in the image scanned by the imaging unit  143  (Step S 1131 ). 
         [0136]    When the display control unit  146   c  determines in Step S 1131  that the paper sheet is not included in the scanned image, the binding orientation setting unit  146   b  cancels the setting of the double-sided printing and the setting of the binding orientation (Step S 1132 ). 
         [0137]    Subsequently, the display control unit  146   c  executes the processing of Step S 1104 . 
         [0138]    When the display control unit  146   c  determines in Step S 1131  that the paper sheet is included in the scanned image, the rotational direction detection unit  146   a  determines whether or not the paper sheet included in the scanned image has been turned over in the same manner as in the processing of Step S 1112  (Step S 1133 ). 
         [0139]    When the rotational direction detection unit  146   a  determines in Step S 1133  that the paper sheet has not been turned over, the display control unit  146   c  executes the processing of Step S 1131 . 
         [0140]    When the rotational direction detection unit  146   a  determines in Step S 1133  that the paper sheet has been turned over, the rotational direction detection unit  146   a  detects the rotational direction of the turning-over with respect to the paper sheet included in the scanned image in the same manner as in the processing of Step S 1113  (Step S 1134 ). 
         [0141]    Subsequently, the binding orientation setting unit  146   b  determines whether or not the rotational direction detected in Step S 1134  for the target page is a reverse direction to the rotational direction detected in Step S 1113  for the previous page (Step S 1135 ). 
         [0142]    When the binding orientation setting unit  146   b  determines in Step S 1135  that the rotational direction detected for the target page is the reverse direction to the rotational direction detected for the previous page, the binding orientation setting unit  146   b  cancels the setting of the binding orientation set in the immediately previous Step S 1114  (Step S 1136 ). 
         [0143]    Subsequently, the display control unit  146   c  sets as the target the printing image on the page previous to the current target page among the plurality of pages of printing images acquired in Step S 1101  (Step S 1137 ), and executes the composite image displaying processing illustrated in  FIG. 8  (Step S 1138 ). 
         [0144]    Subsequently, the display control unit  146   c  executes the processing of Step S 1110 . 
         [0145]    When the binding orientation setting unit  146   b  determines in Step S 1135  that the rotational direction detected for the target page is not the reverse direction to the rotational direction detected for the previous page, the binding orientation setting unit  146   b  determines whether or not the rotational direction detected in Step S 1134  for the target page is the same direction as the rotational direction detected in Step S 1113  for the previous page (Step S 1139 ). 
         [0146]    When the binding orientation setting unit  146   b  determines in Step S 1139  that the rotational direction detected for the target page is not the same direction as the rotational direction detected for the previous page, the display control unit  146   c , then executes the composite image displaying processing illustrated in  FIG. 16  (Step S 1141 ), and executes the processing of Step S 1131 . 
         [0147]    When the binding orientation setting unit  146   b  determines in Step S 1139  that the rotational direction detected for the target page is the same direction as the rotational direction detected for the previous page, the display control unit  146   c  determines whether or not the paper sheet is included in the image scanned by the imaging unit  143  (Step S 1142 ). 
         [0148]    When the display control unit  146   c  determines in Step S 1142  that the paper sheet is not included in the scanned image, the binding orientation setting unit  146   b  cancels the setting of the double-sided printing and the setting of the binding orientation (Step S 1143 ). 
         [0149]    Subsequently, the display control unit  146   c  executes the processing of Step S 1104 . 
         [0150]    When the display control unit  146   c  determines in Step S 1142  that the paper sheet is included in the scanned image, the display control unit  146   c  determines whether or not the head position has been designated (Step S 1144 ). The user of the mobile device  140  can designate the head position by setting the head position of the paper sheet within the scanned image displayed on the display unit  142  through the operation unit  141 . 
         [0151]    When the display control unit  146   c  determines in Step S 1144  that the head position has not been designated, the display control unit  146   c  executes the processing of Step S 1142 . 
         [0152]    When the display control unit  146   c  determines in Step S 1144  that the head position has been designated, the display control unit  146   c  sets as the target the printing image on the page next to the current target page among the plurality of pages of printing images acquired in Step S 1101  (Step S 1145 ), and executes the composite image displaying processing illustrated in  FIG. 16  (Step S 1146 ). 
         [0153]    Subsequently, the control unit  146  determines whether or not all the plurality of pages of printing images acquired in Step S 1101  have been set as the target (Step S 1147 ). 
         [0154]    When the control unit  146  determines in Step S 1147  that all the pages have been set as the target, the display control unit  146   c  executes the processing of Step S 1146 . 
         [0155]    When the control unit  146  determines in Step S 1147  that not all the pages have been set as the target, in other words, when there exists a page that has not yet been set as the target, the display control unit  146   c  executes the processing of Step S 1110 . 
         [0156]    When the control unit  146  determines in Step S 1117  that all the pages have been set as the target, the display control unit  146   c  determines whether or not the paper sheet is included in the image scanned by the imaging unit  143  (Step S 1161 ). 
         [0157]    When the display control unit  146   c  determines in Step S 1161  that the paper sheet is not included in the scanned image, the binding orientation setting unit  146   b  cancels the setting of the double-sided printing and the setting of the binding orientation (Step S 1162 ). 
         [0158]    Subsequently, the display control unit  146   c  executes the processing of Step S 1104 . 
         [0159]    When the display control unit  146   c  determines in Step S 1161  that the paper sheet is included in the scanned image, the rotational direction detection unit  146   a  determines whether or not the paper sheet included in the scanned image has been turned over in the same manner as in the processing of Step S 1112  (Step S 1163 ). 
         [0160]    When the rotational direction detection unit  146   a  determines in Step S 1163  that the paper sheet has not been turned over, the display control unit  146   c  executes the processing of Step S 1161 . 
         [0161]    When the rotational direction detection unit  146   a  determines in Step S 1163  that the paper sheet has been turned over, the rotational direction detection unit  146   a  detects the rotational direction of the turning-over with respect to the paper sheet included in the scanned image in the same manner as in the processing of Step S 1113  (Step S 1164 ). 
         [0162]    Subsequently, the binding orientation setting unit  146   b  determines whether or not the rotational direction detected in Step S 1164  for the target page is a reverse direction to the rotational direction detected in Step S 1113  for the previous page (Step S 1165 ). 
         [0163]    When the binding orientation setting unit  146   b  determines in Step S 1165  that the rotational direction detected for the target page is the reverse direction to the rotational direction detected for the previous page, the binding orientation setting unit  146   b  cancels the setting of the binding orientation set in the immediately previous Step S 1114  (Step S 1166 ). 
         [0164]    Subsequently, the display control unit  146   c  sets as the target the printing image on the page previous to the current target page among the plurality of pages of printing images acquired in Step S 1101  (Step S 1167 ), and executes the composite image displaying processing illustrated in  FIG. 16  (Step S 1168 ). 
         [0165]    Subsequently, the display control unit  146   c  executes the processing of Step S 1110 . 
         [0166]    When the binding orientation setting unit  146   b  determines in Step S 1165  that the rotational direction detected for the target page is not the reverse direction to the rotational direction detected for the previous page, the display control unit  146   c  displays the error indicating that the direction of the turning-over is inappropriate on the display unit  142  (Step S 1169 ), then executes the composite image displaying processing illustrated in  FIG. 16  (Step S 1170 ), and executes the processing of Step S 1161 . 
         [0167]    Next, a description is made of an operation of the image forming system  110  performed when the MFP is used for print the printing image. 
         [0168]    When instructed to perform printing on the paper sheet through the operation unit  141 , the control unit  146  of the mobile device  140  transmits the plurality of pages of printing images acquired in Step S 1101  along with double-sided printing setting information indicating a setting relating to the double-sided printing to the MFP received in Step S 1102  through the network communication unit  144 . Here, the double-sided printing setting information includes information indicating whether or not the double-sided printing has been set in Step S 1109 . Further, the double-sided printing setting information includes information on the binding orientation of each paper sheet set in Step S 1114  when the double-sided printing is set. 
         [0169]    Therefore, the control unit of the MFP uses the double-sided printing setting information transmitted from the mobile device  140  along with the printing image to print the printing image transmitted from the mobile device  140  on the paper sheet by the printer. In other words, when the double-sided printing setting information includes the information indicating that the double-sided printing has not been set, the control unit of the MFP subjects the printing image transmitted from the mobile device  140  to single-sided printing on the paper sheet. On the other hand, when the double-sided printing setting information includes the information indicating that the double-sided printing has been set, the control unit of the MFP subjects the printing image transmitted from the mobile device  140  to the double-sided printing on the paper sheet based on the information on the setting of the binding orientation of each paper sheet included in the double-sided printing setting information. 
         [0170]    As described above, the mobile device  140  causes the user to turn over the actual paper sheet, to thereby set the binding orientation corresponding to the rotational direction of the turning-over with respect to the paper sheet (Steps S 1112  to S 1114 ), and hence it is possible to allow the user to intuitively designate the binding orientation for the double-sided printing performed on the MFP. 
         [0171]    The mobile device  140  causes the user to turn over the actual paper sheet to set the binding orientation (Step S 1114 ), and then causes the user to actually turn over the paper sheet in a rotational direction for cancellation serving as a rotational direction used for canceling the setting, to thereby cancel the setting of the binding orientation (Steps S 1133  to S 1136  or Steps S 1163  to S 1166 ) that allows the user to easily instruct the cancellation of the setting of the binding orientation. 
         [0172]    Here, the mobile device  140  causes the user to turn over the actual paper sheet to set the binding orientation, and then causes the user to actually turn over the paper sheet in the rotational direction for cancellation that is the reverse direction to the rotational direction of the turning-over, in other words, causes the user to actually execute an operation that is reverse to the operation for setting the binding orientation (YES in Step S 1135  or YES in Step S 1165 ), to thereby cancel the setting of the binding orientation (Steps S 1133  to S 1136  or Steps S 1163  to S 1166 ) that allows the user to intuitively instruct the cancellation of the setting of the binding orientation. 
         [0173]    Note that, the mobile device  140  may be provided with the rotational direction for cancellation that is a rotational direction other than the reverse direction to the rotational direction for setting the binding orientation. Further, the mobile device  140  may not be provided with the rotational direction for cancellation itself. 
         [0174]    The mobile device  140  sets the binding orientation for the double-sided printing on the first paper sheet of two successive paper sheets to be subjected to the double-sided printing (Step S 1114 ), and when a rotational direction for shift that is a rotational direction used for shifting to a state of being ready to receive the setting of the binding orientation for the double-sided printing on the second paper sheet is detected (YES in Step S 1139 ), shifts to the state of being ready to receive the setting of the binding orientation for the double-sided printing on the second paper sheet (YES in Step S 1110  and Step S 1112 ). According to this configuration, the mobile device  140  causes the user to turn over the actual paper sheet to set the binding orientation, and then causes the user to actually turn over the paper sheet in the rotational direction for shift, to thereby shift to the state of being ready to receive the setting of the binding orientation for the double-sided printing on the second paper sheet of the two successive paper sheets to be subjected to the double-sided printing that allows the user to easily instruct the shift to the state of being ready to receive the setting of the binding orientation for the double-sided printing on the second paper sheet. Note that “a state of being ready” may be herein referred to as “a ready state.” 
         [0175]    Here, the mobile device  140  causes the user to turn over the actual paper sheet to set the binding orientation, and then causes the user to actually turn over the paper sheet in the rotational direction for shift that is the same direction as the rotational direction of the turning-over (YES in Step S 1139 ), to thereby be able to shift to the state of being ready to receive the setting of the binding orientation for the double-sided printing on the second paper sheet (YES in Step S 1110  and Step S 1112 ). However, the mobile device  140  may be provided with the rotational direction for shift that is a rotational direction other than the same direction as the rotational direction for setting the binding orientation. For example, the mobile device  140  may be configured to employ all rotational directions other than the rotational direction for cancellation as the rotational direction for shift. Further, the mobile device  140  may not be provided with the rotational direction for shift itself when, for example, being configured to shift to the state of being ready to receive the setting of the binding orientation for the double-sided printing on the second paper sheet based on a specific operation performed through the operation unit  141  or being configured in the first place so that all the settings of the binding orientations for the double-sided printing on a plurality of successive paper sheets are the same. 
         [0176]    The mobile device  140  displays the composite image that combines the printing image on the paper sheet within the image scanned by the imaging unit  143 , on the display unit  142  as the preview image (Step S 1204 ), and can therefore reflect the appearance of the actual paper sheet on the preview image, with the result that the preview image close to the actual printed matter can be generated. 
         [0177]    The mobile device  140  recognizes the paper sheet itself within the scanned image by the image recognition technology, to thereby recognize that the paper sheet is included in the scanned image, and can therefore display the composite image that combines the printing image on the paper sheet within the scanned image, on the display unit  142  as the preview image even when the special marker used for recognizing that the paper sheet is included in the scanned image is not formed on the paper sheet. 
         [0178]    Note that, the mobile device  140  may be configured to recognize that the paper sheet is included in the scanned image by reading the special marker used for recognizing that the paper sheet is included in the scanned image from above the paper sheet. 
         [0179]    The mobile device  140  changes the appearance of the preview of the printing image within the composite image based on the output characteristic of the MFP by receiving the designation of the MFP that is to print the printing image on the paper sheet, and hence the preview image suitable for the MFP used for printing the printing image can be easily displayed on the display unit  142 . 
         [0180]    The mobile device  140  displays the composite image that combines the printing image on the paper sheet within the image scanned by the imaging unit  143 , on the display unit  142  as the preview image (Step S 1204 ), and can therefore allow the user to specifically imagine a result of the double-sided printing, with the result that it is possible to allow the user to more intuitively designate the binding orientation for the double-sided printing performed on the MFP. However, the mobile device  140  may be configured to inhibit the preview image from being displayed on the display unit  142  when the binding orientation for the double-sided printing is set in the processing illustrated in  FIG. 13  to  FIG. 15 . 
         [0181]    The mobile device  140  can allow the user to confirm the scanned image displayed on the display unit  142  when causing the user to turn over the actual paper sheet, and can therefore allow the user to confirm that an act of turning over the paper sheet is recognized by the mobile device  140  that can improve operability. However, the mobile device  140  may be configured to inhibit the image scanned by the imaging unit  143  from being displayed on the display unit  142  when the binding orientation for the double-sided printing is set in the processing illustrated in  FIG. 13  to  FIG. 15 . 
         [0182]    Note that, the image forming system  110  includes a mobile device as the electronic device according to the embodiment of the present disclosure, but may include another electronic device such as a PC or the like instead of the mobile device. 
         [0183]    Further, the image forming system  110  includes an MFP as the image forming apparatus according to the embodiment of the present disclosure, but may include another image forming apparatus such as a dedicated printer, a dedicated copier, a dedicated facsimile device, or the like instead of the MFP. 
         [0184]    It should be understood that various changes and modifications to the presently embodiments described herein will be apparent to those skilled in the art. Such changes and modifications can be made without departing from the spirit and scope of the present subject matter and without diminishing its intended advantages. It is therefore intended that such changes and modifications be covered by the appended claims.