Patent Publication Number: US-2004057063-A1

Title: Printing system, controller and display method

Description:
BACKGROUND OF THE INVENTION  
       [0001] 1. Field of the Invention  
       [0002] The present invention relates to a printing system including a controller for providing print data to a printing machine, and the printing machine for printing on a sheet an image represented by the print data provided from the controller. More particularly, the invention relates to a printing system which provides a preview of an image prior to printing of the image on a sheet.  
       [0003] 2. Description of the Background Art  
       [0004] Software applications such as word processing and spreadsheet software applications have the capability of displaying a preview of an image represented by electronically generated print data so that an operator views the preview of the image to determine, in advance, whether or not the print data is to be printed properly.  
       [0005] Such a preview capability is also used in a printing system including a digital printing machine and a controller. The digital printing machine rasterizes page data described in a page description language to directly print an image represented by the resultant print data on a sheet. Preview display in a printing system is generally utilized in such a manner that an operator views, on a display section of the controller, a preview of the image represented by the print data generated by the rasterization process to determine whether or not the image is proper. The operator for the digital printing machine performs printing after recognizing the preview of the image, thereby to prevent printing error due to erroneous settings in the rasterization process.  
       [0006] Sheets to be used in the process of producing prints (or printed matter) are not the same in size and material, but are of a variety of types. Some type of digital printing machine has a plurality of paper feed sections for storing respectively different types of sheets. Such a digital printing machine can print on sheets of a desired type by previously specifying a paper feed section which stores the desired sheets without the need to replace the paper feed sections each time sheets to be used are changed.  
       [0007] To produce a book, for example, having front and back covers made of coated paper and a main body made of plain paper, the digital printing machine controls the feed of paper from the paper feed sections so as to print images for the front and back covers on the coated paper and images for the main body on the plain paper. This achieves printing for production of the desired book. Therefore, the controller for the digital printing machine effects control to bring the print data and the sheets to be fed into proper correspondence with each other.  
       [0008] Conventionally, the digital printing machine displays a so-called preview image in advance so that the operator checks whether or not an image represented by print data is proper and whether or not the image is to be printed in a desired position on a sheet.  
       [0009] However, the conventional preview has been disadvantageous in that the digital printing machine having the plurality of paper feed sections is incapable of allowing the operator to identify a sheet on which an image represented by print data is to be printed. In other words, the printing machine which uses different types of sheets for appropriate purposes is incapable of allowing the operator to check in advance whether or not the print data and the sheet to be used are brought into proper correspondence with each other.  
       [0010] There has been another problem regarding a slip sheet (or an interleaf) to be inserted between printed sheets for distinction between the printed sheets. Specifically, it is impossible for the operator to easily check which sheet is to be used as the slip sheet. Since the preview based on the print data generally contains no information about slip sheets, it is impossible for the operator to check in advance whether a desired slip sheet is to be inserted in a proper position between the printed sheets.  
       SUMMARY OF THE INVENTION  
       [0011] The present invention is intended for a printing system including a controller for providing print data to a printing machine, and the printing machine for printing on a sheet an image represented by the print data provided from the controller. More particularly, the invention is intended for a technique for providing a preview of an image prior to printing of the image on a sheet.  
       [0012] According to the present invention, the printing system comprises: (a) a printing machine having a plurality of paper feed sections, the printing machine using a sheet stored in any one of the plurality of paper feed sections; and (b) a controller for providing print data to the printing machine, the controller including (b-1) an information defining element for defining identification information for identifying the plurality of paper feed sections, (b-2) a paper feed section specifying element for specifying one of the plurality of paper feed sections for feeding the sheet for printing of an image represented by the print data on the sheet, (b-3) an image creating element for creating a preview image, based on the image represented by the print data, and the identification information defined by the information defining element for the paper feed section specified by the paper feed section specifying element, and (b-4) a display element for displaying the preview image created by the image creating element.  
       [0013] This allows an operator to previously recognize the sheet on which the print data is to be printed.  
       [0014] Preferably, the controller further includes (b-5) a position specifying element for specifying a position in which a slip sheet is to be inserted between printed sheets, and (b-6) a slip sheet feed section specifying element for specifying one of the plurality of paper feed sections for feeding a sheet to be used as the slip sheet; and the image creating element creates the preview image, based on the position in which the slip sheet is to be inserted which is specified by the position specifying element, and the identification information defined by the information defining element for the paper feed section specified by the slip sheet feed section specifying element.  
       [0015] This allows the operator to previously recognize the slip sheet insertion position and the sheet for use as the slip sheet, when the slip sheet is to be used.  
       [0016] The present invention is also intended for a method of displaying an image represented by print data. The method comprises the steps of: (a) defining identification information for identifying a plurality of paper feed sections provided in a printing machine; (b) specifying one of the plurality of paper feed sections for feeding a sheet for printing of the image represented by the print data on the sheet; (c) creating a preview image, based on the image represented by the print data, and the identification information defined in the step (a) for the paper feed section specified in the step (b); and (d) displaying the preview image created in the step (c).  
       [0017] This allows the operator to previously recognize the sheet on which the print data is to be printed.  
       [0018] It is therefore an object of the present invention to allow an operator to recognize, prior to printing, whether or not a desired image is to be reliably printed on a desired sheet.  
       [0019] These and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0020]FIG. 1 is a diagram of a printing system according to a preferred embodiment of the present invention;  
     [0021]FIG. 2 is a flowchart for illustrating the operation of the printing system;  
     [0022]FIG. 3A shows a definition menu;  
     [0023]FIG. 3B shows an example of identification information;  
     [0024]FIG. 4A shows a specification menu;  
     [0025]FIG. 4B shows an example of specification information;  
     [0026]FIG. 5A shows another specification menu;  
     [0027]FIG. 5B shows an example of position information;  
     [0028]FIG. 6A shows still another specification menu;  
     [0029]FIG. 6B shows an example of specification information;  
     [0030]FIG. 7 is a flowchart showing the details of a preview display process of a controller;  
     [0031]FIG. 8A shows another definition menu;  
     [0032]FIG. 8B shows an example of definition information;  
     [0033]FIG. 9 shows an example of a correspondence table;  
     [0034]FIG. 10 shows an example of a preview image displayed in the form of a single page;  
     [0035]FIG. 11 shows an example of another preview image displayed in the form of a single page;  
     [0036]FIG. 12 shows an example of still another preview image displayed in the form of a single page;  
     [0037]FIG. 13 shows an example of preview images displayed in list form;  
     [0038]FIG. 14A shows an example of the correspondence table when information about the type of sheets is used as the identification information; and  
     [0039]FIG. 14B shows an example of preview images displayed in list form, based on the correspondence table shown in FIG. 14A. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
     [0040]FIG. 1 is a diagram of a printing system  100  according to the present invention. The printing system  100  comprises a controller  1 , a printing machine  2 , and a communication line CL.  
     [0041] The controller  1  is a device corresponding to a personal computer in common use, and includes a CPU  11 , a display section  12 , an input section  13 , a network I/F (interface)  14 , a media drive  15 , a storage section  16 , and a memory  17 .  
     [0042] The CPU  11  controls the entire controller  1 . In particular, the CPU  11  executes in the memory  17  a program recorded on a media disk  18  to implement functions of the controller  1 .  
     [0043] The display section  12  displays various pieces of information required to display a preview image in the controller  1 . The input section  13  includes a mouse and a keyboard, and is used for operator&#39;s entry of commands into the controller  1 .  
     [0044] The network I/F  14  is intended to establish a connection between the controller  1  and a network not shown. Through the network I/F  14 , the controller  1  can receive page data PD or print data RPD for printing in the printing machine  2  from a terminal (not shown) connected to the network. Additionally, a program for implementing the functions of the controller  1  may be downloaded from a server not shown through the network I/F  14  to the controller  1 . When the printing machine  2  is connected via a network to the controller  1 , the controller  1  sends the print data RPD or a control signal ACD for slip sheet insertion through the network I/F  14  to the printing machine  2 .  
     [0045] The media drive  15  is used to read a program  161  recorded on the media disk  18 . The program  161  read by the media drive  15  is executed by the CPU  11  to implement the functions of the controller  1  as described above. The storage section  16  stores therein the program  161  read by the media drive  15 . The storage section  16  also stores therein various data including the page data PD and the print data RPD.  
     [0046] The communication line CL establishes a connection between the controller  1  and the printing machine  2  for communication therebetween. The controller  1  sends the input data RPD to the printing machine  2 . The controller  1  also sends the control signal ACD for slip sheet insertion through the communication line CL to the printing machine  2 .  
     [0047] The printing machine  2  has the function of printing the print data RPD sent from the controller  1  directly on a sheet  24 . Therefore, the printing machine  2  comprises a control section  20 , paper feed cassettes  21 , a printing section  22 , and a paper stack section  23 .  
     [0048] The control section  20  controls the entire printing machine  2 . The control section  20  receives the print data RPD sent from the controller  1  to selectively feed a sheet  24  for printing thereon an image (also referred to hereinafter as an original image) represented by the print data RPD from a paper feed cassette  21  to the printing section  22 . The control section  20  also converts the received print data RPD into a format printable by the printing section  22  to supply the converted data to the printing section  22 . When the control section  20  receives the control signal ACD, the control section  20  selectively feeds a sheet  24  specified as a slip sheet from a paper feed cassette  21  to the printing section  22 , but does not provide the data of the printable format to the printing section  22 . This allows the sheet  24  specified as the slip sheet to be discharged to the paper stack section  23  without printing on the sheet  24 .  
     [0049] The printing machine  2  has the plurality of paper feed cassettes  21 . In the printing machine  2  according to this preferred embodiment, the plurality of paper feed cassettes  21  are three paper feed cassettes  21   a ,  21   b  and  21   c . However, the number of paper feed cassettes  21  is not limited to three. Although sheets  24  are shown in FIG. 1 as stored only in the paper feed cassette  21   c , the paper feed cassettes  21   a  and  21   b  also store different types of sheets  24 , and the printing machine  2  according to this preferred embodiment can use three types of sheets  24 . In response to a control signal from the control section  20 , each of the paper feed cassettes  21  feeds a sheet  24  stored therein through a conveyor section not shown to the printing section  22 .  
     [0050] The printing section  22  prints on the sheet  24  the original image represented by the print data RPD provided from the control section  20 . Techniques used herein for printing in the printing section  22  include plateless printing such as electrophotographic printing, ink jet printing and thermal sublimation printing, or conventional printing employing plates. The printing section  22  does not print on a sheet  24  fed as the slip sheet.  
     [0051] The paper stack section  23  collects sheets  24  printed by the printing section  22  therein, and also collects sheets  24  discharged as slip sheets which are not printed. As a result, the sheets  24  collected in the paper stack section  23  are treated as printed sheets  25 .  
     [0052] The memory  17  is a work area in which the CPU  11  executes the program  161  stored in the storage section  16 . As a result of the execution of the program  161  by the CPU  11 , the functions of an information defining section  171 , a paper feed cassette specifying section  172 , a position specifying section  173 , a slip sheet feed cassette specifying section  174 , an image creating section  175  and an image display section  176  are implemented in the memory  17 .  
     [0053] For each of the paper feed cassettes  21  provided in the printing machine  2 , the information defining section  171  defines identification information CC for individual identification of the paper feed cassettes  21 . The defined identification information CC is used for discrimination between the paper feed cassettes  21   a ,  21   b  and  21   c  in a process to be described later. In this preferred embodiment, information regarding “color” is defined for each of the paper feed cassettes  21   a ,  21   b  and  21   c  and used as the identification information CC. However, the name of each paper feed cassette  21 , a cassette number assigned to each paper feed cassette  21 , the type of sheets  24  stored in each paper feed cassette  21 , and the like may be used as the identification information CC. In other words, the identification information CC may be any information which allows an operator to easily identify the paper feed cassettes  21   a ,  21   b  and  21   c.    
     [0054] The paper feed cassette specifying section  172  specifies a paper feed cassette  21  for feeding a sheet  24  on which the original image represented by the print data RPD is to be printed among the plurality of paper feed cassettes  21   a ,  21   b  and  21   c . Information indicating the paper feed cassette  21  specified by the paper feed cassette specifying section  172  is stored as specification information CJ in a correspondence table  1751  to be described later. In the printing machine  2  according to this preferred embodiment, only sheets  24  of a single type are stored in any one of the paper feed cassettes  21 . Since there is a one-to-one correspondence between the paper feed cassettes  21  and the types of sheets  24 , specifying one of the paper feed cassettes  21  is equivalent to specifying one of the types of sheets  24 . Thus, when the paper feed cassette specifying section  172  specifies a paper feed cassette  21  corresponding to the print data RPD, a sheet  24  stored in the specified paper feed cassette  21  is fed to the printing section  22  and printed in the process of printing the original image represented by the print data RPD.  
     [0055] The position specifying section  173  specifies a position in which a slip sheet is to be inserted between the printed sheets  25  in the process of producing the printed sheets  25 . The slip sheet insertion position specified by the position specifying section  173  is stored as position information AI in the correspondence table  1751 . The slip sheet is used for distinction between the sheets  24  printed and collected in the paper stack section  23 , but may be used to prevent undried ink from transferring to the back surfaces of other sheets  24 . The slip sheet may be used for any purpose. The sheet  24  for use as the slip sheet is preferably different, for example, in color, size or material from the sheet  24  to be printed. In general, printing is not performed on the slip sheet.  
     [0056] The slip sheet feed cassette specifying section  174  specifies a paper feed cassette  21  for feeding the sheet  24  for use as the slip sheet among the plurality of paper feed cassettes  21   a ,  21   b  and  21   c . Information about the paper feed cassette  21  specified by the slip sheet feed cassette specifying section  174  is stored as specification information AJ in the correspondence table  1751 .  
     [0057] The image creating section  175  creates a preview image PV based on the original image represented by the print data RPD. The image creating section  175  includes the correspondence table  1751  and an information combining section  1752 .  
     [0058] The correspondence table  1751  stores the specification information CJ, and is a table for storing a correspondence between the print data RPD and the paper feed cassette  21  specified by the paper feed cassette specifying section  172 . The correspondence table  1751  also stores a correspondence between the print data RPD and the paper feed cassette  21  specified by the slip sheet feed cassette specifying section  174  although the print data RPD is absent when printing is not performed on the slip sheet. Additionally, the correspondence table  1751  stores the position information AI specified by the position specifying section  173  and the specification information AJ in association with each other.  
     [0059] The information combining section  1752  combines the preview image PV created by the image creating section  175  and the identification information CC defined by the information defining section  171  together, based on the correspondence between the print data RPD and the paper feed cassette  21  which is stored in the correspondence table  1751 , to create a preview image CPV. Specifically, the information combining section  1752  references the correspondence table  1751  to specify the identification information CC corresponding to the preview image PV, and then creates an image combination of the specified identification information CC and the preview image PV to provide the preview image CPV. The identification information CC corresponding to the preview image PV refers to the identification information CC indicating the paper feed cassette  21  specified by the paper feed cassette specifying section  172  for the print data RPD from which the preview image PV originates.  
     [0060] The information combining section  1752  combines the corresponding identification information CC with any one of the “background,” “periphery” or “pattern” of the preview image PV. In this preferred embodiment, “color” is defined as the identification information CC by the information defining section  171 , as discussed above. When the identification information CC is combined with the “background,” the background of the preview image PV has the “color” defined as the corresponding identification information CC. Displaying the preview image CPV thus created on the display section  12  allows the operator to easily identify which paper feed cassette  21  is to be used during the printing of the original image represented in the preview image CPV, based on the “color” of the background being used. Since the type of sheets  24  stored in the paper feed cassette  21  is specified, the operator can identify the type of sheets  24  to be used by identifying the paper feed cassette  21  to be used. When the identification information CC is combined with the “periphery,” the peripheral portion of the preview image PV has the “color” defined as the corresponding identification information CC. When the identification information CC is combined with the “pattern,” the pattern of the preview image PV has the “color” defined as the corresponding identification information CC. When the cassette number or the name of the paper feed cassette  21  is defined as the identification information CC, the information combining section  1752  creates the preview image CPV which uses the cassette number or the name of the paper feed cassette as the background, periphery or pattern of the preview image PV.  
     [0061] The information combining section  1752  creates the preview image CPV also based on the correspondence between the position information AI and the paper feed cassette  21  in the correspondence table  1751 . For the paper feed cassette  21  specified by the slip sheet feed cassette specifying section  174 , the information combining section  1752  creates the preview image CPV with only the identification information CC displayed, because of the absence of the print data RPD. The position information AI is associated with the created preview image CPV.  
     [0062] The image display section  176  displays a preview window PW on the display section  12 , and displays the preview image CPV created by the image creating section  175  within the preview window PW. The image display section  176  includes a list display section  1761 . If a plurality of preview images CPV are created by the image creating section  175  (the information combining section  1752 ), the list display section  1761  displays the plurality of preview images CPV on a reduced scale in list form within the preview window PW. In this process, the preview images CPV for the print data RPD are listed in the order of printing for production of the printed sheets  25 , with the preview image CPV for the slip sheet inserted in a predetermined position in accordance with the position information AI.  
     [0063]FIG. 2 is a flowchart for illustrating the operation of the printing system  100 . The controller  1  stores the print data RPD in the storage section  16  in Step S 1 . A rasterization processor (not shown) included in the printing system  100  rasterizes the page data PD to generate the print data RPD. The page data PD is generated in a page description language at a terminal (not shown), and is transmitted through the network I/F  14  to the printing system  100 . Alternatively, the print data RPD may be generated directly at the terminal and transmitted through the network I/F  14  to the printing system  100 . Otherwise, the print data RPD generated at a terminal unconnected to the network may be stored in the media disk  18  which in turn is read by the media drive  15  to acquire the print data RPD.  
     [0064] In Step S 2 , the information defining section  171  defines the identification information CC. The operator manipulates the input section  13  of the controller  1  to do input relating to the definition of the identification information CC in the information defining section  171 .  
     [0065]FIG. 3A shows a definition menu MCC. The definition menu MCC is displayed on the display section  12  by the information defining section  171  for definition of the identification information CC for each of the paper feed cassettes  21 . The definition menu MCC includes paper feed cassette name display boxes  31 , paper feed cassette color selection boxes  32  ( 32   a ,  32   b  and  32   c ), color change buttons  33  ( 33   a ,  33   b  and  33   c ), an OK button  34 , and a cancel button  35 . The operator enters necessary information into the definition menu MCC in Step S 2 .  
     [0066] The paper feed cassette name display boxes  31  display the names of the paper feed cassettes  21  provided in the printing machine  2  and the types (sizes, materials and the like) of sheets  24  stored therein. In this preferred embodiment, the paper feed cassettes  21   a ,  21   b  and  21   c  are named #1, #2 and #3, respectively. The “name of paper feed cassette  21 ” in each of the paper feed cassette name display boxes  31  is displayed on the definition menu MCC by the information defining section  171  in accordance with the number of paper feed cassettes  21  provided in the printing machine  2 . The information defining section  171  receives through the communication line CL information about the paper feed cassettes  21  managed by the control section  20  of the printing machine  2  (or the information about the number of paper feed cassettes  21  and the types of sheets  24  stored therein) to present the display of the paper feed cassette name display boxes  31  on the definition menu MCC in accordance with the received information. For definition of the identification information CC, it is sufficient to display only the “name of paper feed cassette  21 ” in each of the paper feed cassette name display boxes  31 . In the printing system  100 , however, the paper feed cassettes  21  are specified for the purpose of specifying the types of sheets  24  to be used. It is, therefore, preferable to configure the definition menu MCC so that displaying the “type of sheets  24 ” in each of the paper feed cassette name display boxes  31  allows the operator to define the identification information CC while knowing the type of sheets  24  corresponding to (or stored in) each of the paper feed cassettes  21 , as illustrated in this preferred embodiment. Alternatively, the operator may individually input to the information defining section  171  the names and number of paper feed cassettes  21  provided in the printing machine  2  and the types of sheets  24  stored therein.  
     [0067] The paper feed cassette color selection boxes  32  and the color change buttons  33  are used to define color information as the identification information CC for each of the paper feed cassettes  21 . The paper feed cassette color selection boxes  32   a ,  32   b  and  32   c  are paired with the color change buttons  33   a ,  33   b  and  33   c , respectively.  
     [0068] The information defining section  171  displays on the definition menu MCC one paper feed cassette color selection box  32  and one color change button  33  for each of the paper feed cassettes  21  displayed in the paper feed cassette name display boxes  31 . For example, the paper feed cassette color selection box  32   a  and the color change button  33   a  which constitute a pair correspond to the paper feed cassette  21   a . When the operator manipulates the input section  13  to press any one of the color change buttons  33 , the information defining section  171  displays information about a plurality of colors in the paper feed cassette color selection box  32  corresponding to the pressed color change button  33 . Then, the operator further manipulates the input section  13  to select a desired color as the information for identification of the corresponding paper feed cassette  21  from the information about the plurality of colors displayed in the corresponding paper feed cassette color selection box  32 . The operator repeats this operation for each of the paper feed cassettes  21 , whereby the information defining section  171  defines the identification information CC for each paper feed cassette  21  so that the color information selected by the operator corresponds to each paper feed cassette  21 .  
     [0069] The operator presses the OK button  34  when the input to the definition menu MCC is completed. If the operator completes the selection of the color information in each of the paper feed cassette color selection boxes  32  with satisfactory results, the operator manipulates the input section  13  to press the OK button  34 . This causes the information defining section  171  to define the identification information CC using the inputs to the definition menu MCC to finish displaying the definition menu MCC.  
     [0070] The operator presses the cancel button  35  when the operator wants to interrupt displaying the definition menu MCC. This causes the information defining section  171  to finish displaying the definition menu MCC without waiting for the completion of the definition of the identification information CC.  
     [0071]FIG. 3B shows an example of the identification information CC. As described above, the identification information CC is defined for each of the paper feed cassettes  21  by the information defining section  171  as a result of input to the definition menu MCC. The identification information CC is shown in FIG. 3B as defined to contain the information shown in FIG. 3A by the operator pressing the color change buttons  33  corresponding to the paper feed cassette color selection boxes  32  shown on the definition menu MCC. In this preferred embodiment, the definitions of the identification information CC are as follows: “R (red)” for the paper feed cassette  21   a  (named “#1”) having “A4 (A4-size) coated paper” stored therein; “G (green)” for the paper feed cassette  21   b  (named “#2”) having “A4 plain paper” stored therein; and “B (blue)” for the paper feed cassette  21   c  (named “#3”) having “A4 colored paper” stored therein. The identification information CC is temporarily stored in the memory  17 .  
     [0072] Referring again to FIG. 2, the paper feed cassette specifying section  172  specifies a paper feed cassette  21  for the print data RPD to create the specification information CJ in Step S 3 . In Step S 3 , the operator manipulates the input section  13  of the controller  1  to do input to the paper feed cassette specifying section  172 , whereby the specification information CJ is created. The specification information CJ indicates a correspondence between the print data RPD and the paper feed cassette  21  for feeding a sheet  24  on which the print data RPD is to be printed.  
     [0073]FIG. 4A shows a specification menu MCJ. The specification menu MCJ is displayed on the display section  12  by the paper feed cassette specifying section  172  for creation of the specification information CJ. To enable operator&#39;s input to specify the paper feed cassettes  21 , the specification menu MCJ includes paper feed cassette name display boxes  41 , print data selection boxes  42  ( 42   a ,  42   b  and  42   c ), print data change buttons  43  ( 43   a ,  43   b  and  43   c ), an OK button  44 , and a cancel button  45 . The paper feed cassette name display boxes  41  are similar to the paper feed cassette name display boxes  31  shown in FIG. 3A, and will not be described.  
     [0074] The print data selection boxes  42  and the print data change buttons  43  are used to specify the print data RPD as the specification information CJ for each of the paper feed cassettes  21 . The print data selection boxes  42   a ,  42   b  and  42   c  are paired with the print data change buttons  43   a ,  43   b  and  43   c , respectively. The paper feed cassette specifying section  172  displays on the specification menu MCJ one print data selection box  42  and one print data change button  43  for each of the paper feed cassettes  21  displayed in the paper feed cassette name display boxes  41 . When the operator manipulates the input section  13  to press one of the displayed print data change buttons  43 , the paper feed cassette specifying section  172  searches the storage section  16  to display a list of print data RPD stored in the storage section  16  in corresponding one of the print data selection boxes  42 . The operator further manipulates the input section  13  to select desired print data RPD among the plurality of print data RPD displayed in the corresponding print data selection box  42 . By repeating this operation, the paper feed cassette specifying section  172  creates the specification information CJ so that a sheet  24  stored for each paper feed cassette  21  is fed for printing of the selected print data RPD. For a single paper feed cassette  21 , a plurality of print data RPD may be specified from the list of print data RPD displayed in the corresponding print data selection box  42 . In this case, the plurality of print data RPD specified are printed on the same type of sheets  24 . For a paper feed cassette  21  which is not to be used for printing such as the paper feed cassette  21   c  (named “#3”), the print data selection box  42   c  may be blank as shown in FIG. 4A without specifying the print data RPD.  
     [0075] The operator presses the OK button  44  when the input to the specification menu MCJ is completed. If the operator completes the selection of the print data RPD in each of the print data selection boxes  42  with satisfactory results, the operator manipulates the input section  13  to press the OK button  44 . This causes the paper feed cassette specifying section  172  to define the specification information CJ using the inputs to the specification menu MCJ to finish displaying the specification menu MCJ.  
     [0076] The operator presses the cancel button  45  when the operator wants to interrupt displaying the specification menu MCJ. This causes the paper feed cassette specifying section  172  to finish displaying the specification menu MCJ without waiting for the completion of the creation of the specification information CJ. Although the specification menu MCJ in this preferred embodiment is configured so as to specify the print data RPD for each paper feed cassette  21 , a paper feed cassette  21  may be specified for each print data RPD. In other words, the specification menu MCJ is required only to be configured so that the operator can specify the correspondences between the print data RPD and the paper feed cassettes  21 .  
     [0077]FIG. 4B shows an example of the specification information CJ. As described above, the specification information CJ is created by the paper feed cassette specifying section  172  as a result of input to the specification menu MCJ. The specification information CJ is shown in FIG. 4B as created to contain the information shown in FIG. 4A by the operator pressing the print data change buttons  43  corresponding to the print data selection boxes  42  shown on the specification menu MCJ. In this preferred embodiment, the specified print data RPD are as follows: “RPD 1 ” for the paper feed cassette  21   a  (named “#1”); and “RPD 2 ” for the paper feed cassette  21   b  (named “#2”). This allows the printing machine  2  to do printing in a process to be described later by feeding a sheet  24  from the paper feed cassette  21   a  named “#1” when printing the print data RPD 1  and by feeding a sheet  24  from the paper feed cassette  21   b  named “#2” when printing the print data RPD 2 . For the paper feed cassette  21   c , no specification information CJ is created since no print data RPD is specified. The specification information CJ is temporarily stored in the memory  17 .  
     [0078] Referring again to FIG. 2, the operator selects whether to use a slip sheet or not, in Step S 4 . The processing proceeds to Step S 5  when the slip sheet is to be used for distinction between the plurality of printed sheets  25 . The processing proceeds to Step S 6  when no slip sheets are to be used.  
     [0079] In Step S 5 , the position specifying section  173  specifies the position in which a slip sheet is to be inserted, and the slip sheet feed cassette specifying section  174  specifies a paper feed cassette  21  for feeding the slip sheet.  
     [0080]FIG. 5A shows a specification menu MAI. The specification menu MAI is displayed on the display section  12  by the position specifying section  173  for creation of the position information AI. The position information AI refers to information indicating the position in which a slip sheet is to be inserted between the printed sheets  25 . The specification menu MAI includes a job-by-job specification area  51 , a page specification area  52 , a repetition specification area  53 , an OK button  54 , and a cancel button  55 .  
     [0081] The job-by-job specification area  51  is used when a slip sheet is to be inserted each time the single print data RPD is printed while the process of printing the single print data RPD is regarded as one job. The operator manipulates the input section  13  to press a specification button  51   a  provided in the job-by-job specification area  51 , whereby the position specifying section  173  creates the position information AI. The slip sheet insertion position is specified as the next position after a sheet  24  constituting the last page for each print data RPD.  
     [0082] The page specification area  52  is used when a slip sheet is to be inserted in a specific position between the printed sheets  25 . The operator manipulates the input section  13  to press a specification button  52   a  provided in the page specification area  52 , and to input into a specification box  52   b  a page number where the slip sheet is to be inserted. This causes the position specifying section  173  to create the position information AI so that the slip sheet is to be inserted at the page number inputted to the specification box  52   b . The slip sheet insertion position is specified as the next position after a sheet  24  constituting a page immediately preceding a page having the page number inputted to the specification box  52   b.    
     [0083] The repetition specification area  53  is used when a slip sheet is to be inserted after every specific number of pages of the printed sheets  25 . The operator manipulates the input section  13  to press a specification button  53   a  provided in the repetition specification area  53 , and to input the number of pages into a specification box  53   b . This causes the position specifying section  173  to create the position information AI so that the slip sheet is to be inserted after every number of pages inputted to the specification box  53   b . The slip sheet insertion position is specified as the next position after a sheet  24  constituting the last page each time sheets  24  corresponding to the number of pages inputted to the specification box  53   b  are printed.  
     [0084] The operator presses the OK button  54  when the input to the specification menu MAI is completed. When the operator manipulates the input section  13  to press the OK button  54 , the position specifying section  173  creates the position information AI using the inputs to the specification menu MAI to finish displaying the specification menu MAI.  
     [0085] The operator presses the cancel button  55  when the operator interrupts displaying the specification menu MAI. When the operator presses the cancel button  55 , the position specifying section  173  finishes displaying the specification menu MAI without creating the position information AI.  
     [0086]FIG. 5B shows an example of the position information AI. The position information AI is shown in FIG. 5B as obtained when the operator presses the specification button  51   a  on the specification menu MAI. As shown in FIG. 5B, the created position information AI indicates that a slip sheet is to be inserted each time the print data RPD is printed on the single sheet  24 . The created position information AI is temporarily stored in the memory  17 .  
     [0087] In Step S 5 , the slip sheet feed cassette specifying section  174  displays a specification menu MAJ on the display section  12  for specification of a paper feed cassette  21  for feeding the slip sheet.  
     [0088]FIG. 6A shows the specification menu MAJ. The specification menu MAJ is displayed for creation of the specification information AJ. The specification menu MAJ includes a selection box  61 , a change button  62 , an OK button  63 , and a cancel button  64 . The specification information AJ refers to information indicating the paper feed cassette  21  for feeding the slip sheet.  
     [0089] The selection box  61  and the change button  62  are used to specify the paper feed cassette  21  for feeding the slip sheet. The selection box  61  is paired with the change button  62 . When the operator manipulates the input section  13  to press the change button  62 , the slip sheet feed cassette specifying section  174  displays a list of the paper feed cassettes  21  provided in the printing machine  2  in the selection box  61 . The operator further manipulates the input section  13  to select a desired paper feed cassette  21  among the plurality of paper feed cassettes  21   a ,  21   b  and  21   c  displayed in the selection box  61 . The slip sheet feed cassette specifying section  174  creates the specification information AJ indicating the paper feed cassette  21  thus selected.  
     [0090] The operator presses the OK button  63  after the input to the specification menu MCJ is completed. When the operator manipulates the input section  13  to press the OK button  63 , the slip sheet feed cassette specifying section  174  creates the specification information AJ using the inputs to the specification menu MAJ to finish displaying the specification menu MAJ.  
     [0091] The operator presses the cancel button  64  when the operator interrupts displaying the specification menu MAJ. When the operator presses the cancel button  64 , the slip sheet feed cassette specifying section  174  finishes displaying the specification menu MAJ without creating the specification information AJ.  
     [0092]FIG. 6B shows an example of the specification information AJ. The specification information AJ is shown in FIG. 6B as obtained when the operator do input to the selection box  61  and the change button  62  on the specification menu MAJ so as to specify the paper feed cassette  21   c  (named “#3”) as the paper feed cassette  21  for feeding the slip sheet. The created specification information AJ is temporarily stored in the memory  17 .  
     [0093] Although the printing system  100  operates in the sequence of Steps S 1  to S 5  in the above description, the sequence of operations of the printing system  100  is not limited to this sequence. For example, the operations in Steps S 4  and S 5  may be carried out prior to the operations in Steps S 1  to S 3 . The sequence of operations in Steps S 2  and S 3  may be altered.  
     [0094] The definition menu MCC and the specification menus MCJ, MAI, MAJ are separately displayed in the above description. However, these menus may be displayed at the same time on the display section  12 . Alternatively, a definition menu into which the above-mentioned menus are integrated may be displayed on the display section  12 .  
     [0095] Referring again to FIG. 2, the controller  1  of the printing system  100  presents a preview display of the print data RPD on the display section  12  in Step S 6 .  
     [0096]FIG. 7 is a flowchart for illustrating the operation of the controller  1  of the printing system  100  in Step S 6  in detail. First, the image creating section  175  creates definition information PJ regarding a preview display of the print data RPD in Step S 61 .  
     [0097]FIG. 8A shows a definition menu MPJ. The operator manipulates the input section  13  to do input to the definition menu MPJ, whereby the image creating section  175  creates the definition information PJ. To this end, the definition menu MPJ includes a display format definition area  81 , an identification display definition area  82 , an image specification area  83 , an OK button  84 , and a cancel button  85 .  
     [0098] The display format definition area  81  is intended for defining the display format of the preview image PV to be displayed in the preview window PW. Specifically, the display format definition area  81  is used to define whether to display a preview image PV in the form of a single page or a plurality of preview images PV in list form in the preview window PW. Therefore, the display format definition area  81  includes a single page specification button  81   a  and a list specification button  81   b . For display of the preview image PV in the form of a single page in the preview window PW, the operator manipulates the input section  13  to press the single page specification button  81   a . For display of the plurality of preview images PV in list form, on the other hand, the operator presses the list specification button  81   b . It should be noted that the single page specification button  81   a  and the list specification button  81   b  are pressed in mutually exclusive manner, and are not permitted to be pressed at the same time. Additionally, the printing system  100  in this preferred embodiment does not directly display the preview image PV but displays the preview image CPV obtained by the image combination of the identification information CC and the preview image PV.  
     [0099] The identification display definition area  82  is intended for defining the display format of the identification information CC to be displayed in combination with the preview image PV. The identification display definition area  82  includes a background display button  82   a , a periphery display button  82   b , and a pattern display button  82   c.    
     [0100] The operator presses the background display button  82   a  when displaying the preview image PV in combination with the identification information CC as the background of the preview image PV in the preview window PW.  
     [0101] The operator presses the periphery display button  82   b  when displaying the preview image PV in combination with the identification information CC as the peripheral portion of the preview image PV in the preview window PW.  
     [0102] The operator presses the pattern display button  82   c  when displaying the preview image PV in combination with the identification information CC as the pattern of the preview image PV in the preview window PW.  
     [0103] It should be noted that the background display button  82   a , the periphery display button  82   b  and the pattern display button  82   c  are pressed in mutually exclusive manner, and are not permitted to be pressed at the same time.  
     [0104] The image specification area  83  is used when the operator specifies the print data RPD to be displayed as the preview image PV in the preview window PW. The operator specifies the print data RPD to be displayed in the preview window PW by inputting the name or page number of desired print data RPD to the image specification area  83 . A plurality of print data RPD may be specified in the image specification area  83 .  
     [0105] The operator presses the OK button  84  after the input to the definition menu MPJ is completed. When the operator manipulates the input section  13  to press the OK button  84 , the image creating section  175  creates the definition information PJ using the inputs to the definition menu MPJ to finish displaying the definition menu MPJ.  
     [0106] The operator presses the cancel button  85  when the operator interrupts displaying the definition menu MPJ. When the operator presses the cancel button  85 , the image creating section  175  finishes displaying the definition menu MPJ without creating the definition information PJ.  
     [0107]FIG. 8B shows an example of the definition information PJ. As described above, the definition information PJ is created by the image creating section  175  as a result of input to the definition menu MPJ. The definition information PJ is shown in FIG. 8B as created by the image creating section  175  when the operator presses the single page specification button  81   a  and the background display button  82   a  and inputs “RPD  1 ” and “RPD 2 ” to the image specification area  83  on the definition menu MPJ.  
     [0108] Referring again to FIG. 7, the image creating section  175  acquires and stores in the correspondence table  1751  the identification information CC, the specification information CJ, the position information AI and the specification information AJ temporarily stored in the memory  17  in Step S 62 .  
     [0109]FIG. 9 shows an example of the correspondence table  1751 . The correspondence table  1751  is shown in FIG. 9 as created by the image creating section  175 , based on the identification information CC, the specification information CJ, the position information AI and the specification information AJ shown in FIGS. 3B, 4B,  5 B and  6 B.  
     [0110] As shown in FIG. 9, the paper feed cassette  21   a  (named “#1” in FIG. 9) having stored therein the sheets  24  whose type is “A4 coated paper” is related to the identification information CC indicating “R (red).” Based on the specification information CJ, the correspondence table  1751  indicates that the sheet  24  is to be fed from the paper feed cassette  21   a  when printing the print data RPD 1 . From the specification information AJ, it is found that the paper feed cassette  21   a  is selected to print the print data RPD but is not selected as the paper feed cassette  21  for feeding the slip sheet. The position information AI is not related to the paper feed cassette  21   a.    
     [0111] Similarly, the paper feed cassette  21   b  (named “#2” in FIG. 9) is related to the identification information CC indicating “G (green)” and is selected to feed the sheet  24  for printing the print data “RPD 2 .” Information relating to the slip sheet is not related to the paper feed cassette  21   b.    
     [0112] On the other hand, the paper feed cassette  21   c  (named “#3” in FIG. 9) having stored therein the sheets  24  whose type is “A4 colored paper” is related to the identification information CC indicating “B (blue),” but is not related to the print data RPD indicated by the specification information CJ. However, the correspondence between the slip sheet insertion position “every job” indicated by the position information AI and “#3” indicated by the specification information AJ shows that the paper feed cassette  21   c  is selected to feed the slip sheet.  
     [0113] Referring again to FIG. 7, the image creating section  175  creates a preview image CPV in Step S 63 , based on the definition information PJ created in Step S 61  and the correspondence table  1751  created in Step S 62 .  
     [0114] The image creating section  175  first references the definition information PJ to identify the print data RPD to be displayed as the preview image PV, thereby acquiring the identified print data RPD from the storage section  16 . Then, the image creating section  175  identifies the paper feed cassette  21  corresponding to the acquired print data RPD from the correspondence table  1751  to acquire the size of a display area PE from the information relating to the identified paper feed cassette  21 . The image creating section  175  creates the preview image PV having the size of the display area PE from the acquired print data RPD.  
     [0115] The operation of the image creating section  175  in Step S 63  will be described using a specific example shown in FIGS. 8B and 9. The image creating section  175  references the definition information PJ to identify the print data RPD 1  specified as the print data RPD to be preview-displayed, thereby acquiring the print data RPD 1  from the storage section  16 . Then, the image creating section  175  references the correspondence table  1751  to acquire information relating to the paper feed cassette  21  corresponding to the acquired print data RPD 1  (or the paper feed cassette  21  having stored therein the sheets  24  for printing the print data RPD 1  thereon). As shown in FIG. 9, the paper feed cassette  21   a  (named “#1”) is related to the print data RPD 1 , and “A4 coated paper” is stored as the information relating to the paper feed cassette  21   a . Thus, the image creating section  175  acquires “A4” as the size of the display area PE in which the preview image PV (referred to hereinafter as a “preview image PV  1 ”) of the print data RPD  1  is to be displayed. Then, the image creating section  175  calculates the scale factor of the original image represented by the print data RPD  1  for the size “A4” of the display area PE, to create the preview image PV by skipping or reducing pixel data constituting the print data RPD 1  so as to satisfy the calculated scale factor. Since the definition information PJ shown in FIG. 9 also specifies the print data RPD 2  as the print data RPD to be preview-displayed, the image creating section  175  repeatedly performs a similar operation on the print data RPD 2  to create another preview image PV.  
     [0116] In the printing system  100  according to this preferred embodiment, the controller  1  previously brings the information about each paper feed cassette  21  received from the printing machine  2  into correspondence with the identification information CC to store the correspondence therebetween in the correspondence table  1751 , when defining the identification information CC. However, the controller  1  may receive the information about each paper feed cassette  21  from the printing machine  2  when acquiring the size of the display area PE.  
     [0117] After the creation of the preview images PV, the information combining section  1752  of the image creating section  175  references the correspondence table  1751  and the definition information PJ to create a preview image CPV for each preview image PV in Step S 64 . The information combining section  1752  creates the preview image CPV by combining the identification information CC with the preview image PV created in Step S 63 . In this step, the information combining section  1752  references the identification display (or the display format of the identification information CC) defined in the definition information PJ to determine how to combine the identification information CC with the preview image PV.  
     [0118] When the identification display is defined as “background” in the definition information PJ as shown in FIG. 8B, the information combining section  1752  references the correspondence table  1751  to create a background image BV based on the identification information CC defined for the paper feed cassette  21  for use in printing of the print data RPD. The display size of the background image BV is required only to be greater than the size of the display area PE determined from the size of the sheets  24  stored in the paper feed cassette  21 . The information combining section  1752  overlays the preview image PV upon the background image BV to create the preview image CPV. The preview image CPV containing the identification information CC in the form of the “background” is referred to hereinafter as a “preview image BCPV.” 
     [0119] When the identification display is defined as “periphery” in the definition information PJ, the information combining section  1752  references the correspondence table  1751  to create a periphery image SV based on the identification information CC defined for the paper feed cassette  21  for use in printing of the print data RPD. The display size of the periphery image SV is made equal to the size of the display area PE determined from the size of the sheets  24  stored in the paper feed cassette  21 . It is desirable that the width of a frame constituting the periphery image SV is defined as an initial condition in the information combining section  1752 . Alternatively, the operator may additionally define the width of the frame of the periphery image SV. The information combining section  1752  overlays the periphery image SV upon the preview image PV to create the preview image CPV. The preview image CPV containing the identification information CC in the form of the “periphery” is referred to hereinafter as a “preview image SCPV.” 
     [0120] When the identification display is defined as “pattern” in the definition information PJ, the information combining section  1752  references the correspondence table  1751  to create a pattern image DV based on the identification information CC defined for the paper feed cassette  21  for use in printing of the print data RPD. The display size of the pattern image DV is made equal to the size of the display area PE determined from the size of the sheets  24  stored in the paper feed cassette  21 . The information combining section  1752  combines the pattern image DV with the preview image PV by “ORing” the images DV and PV, to create the preview image CPV. The preview image CPV containing the identification information CC in the form of the “pattern” is referred to hereinafter as a “preview image DCPV.” 
     [0121] On the other hand, when a slip sheet is to be used, no preview image PV corresponding to the slip sheet is created in Step S 63 . Thus, only the size of the display area PE is acquired from the information about the paper feed cassette  21  for feeding the slip sheet in Step S 63 . Then, in Step S 64 , the information combining section  1752  creates one of the background image BV, the periphery image SV and the pattern image DV from the identification information CC indicating the paper feed cassette  21  for feeding the slip sheet to create the preview image CPV in accordance with the size of the acquired display area PE. The preview image CPV thus created for a slip sheet is referred to hereinafter as a “preview image ACPV.” 
     [0122] Next, in Step S 65 , the image display section  176  displays the preview window PW on the display section  12 , and displays the preview image CPV created in Step S 64  within the preview window PW. In this step, the image display section  176  references the definition information PJ to display the preview image CPV in a format specified as the display format of the preview image PV. In this preferred embodiment, either “single page” or “list” is selectable as the display format of the preview image PV.  
     [0123]FIGS. 10 through 12 show preview images CPV displayed in the “single page” format within the preview window PW. When any one of the preview images CPV shown in FIGS. 10 through 12 is displayed on the display section  12 , the operator can check whether or not the print data RPD to be printed is proper and whether or not the position and size of the print data RPD to be printed are proper relative to the sheet  24 , based on the original image represented in the preview image PV and the position and size of the preview image PV relative to the display area PE, as in the case of the conventional preview display.  
     [0124]FIG. 10 shows an example of the preview image BCPV being displayed. The display area PE indicating the size of the sheet  24  is represented by the inner frame. The preview image BCPV is greater in size than the display area PE, and only the original image represented by the print data RPD is presented within the display area PE. For the preview image BCPV, the background image BV indicating the identification information CC is used as the background of the preview image PV (or the display area PE). The preview image BCPV is similar to an image such that the sheet  24  indicated by the display area PE is attached to a panel on which the background image BV is painted. Thus, the operator views the background image BV to thereby recognize which paper feed cassette  21  is to be used for printing of the original image (represented by the print data RPD) presented within the display area PE. In this preferred embodiment, since the identification information CC is information relating to “color,” the operator recognizes the color of the background image BV to recognize the paper feed cassette  21  to be used. As an example, when the identification information CC is defined as shown in FIG. 3B, the background image BV displayed in “R (red)” allows the operator to recognize that the paper feed cassette  21   a  (named “#1”) is to be used for printing of the print data RPD and that the original image represented by the print data RPD is to be printed on the sheet  24  stored in the paper feed cassette  21   a . The display area PE indicated in the preview image BCPV is similar to the conventional preview image, and is effective if the operator is accustomed to the conventional preview image.  
     [0125]FIG. 11 shows an example of the preview image SCPV being displayed. The preview image SCPV is equal in size to the display area PE, and contains the periphery image SV in its peripheral portion. In the preview image SCPV, a portion of the image presented within the display area PE which corresponds to the periphery image SV is not to be actually printed on the sheet  24 . The operator views the periphery image SV to thereby recognize which paper feed cassette  21  is to be used for printing of the original image (represented by the print data RPD) shown in FIG. 11. As an example, when the identification information CC is defined as shown in FIG. 3B, the periphery image SV displayed in “R (red)” allows the operator to recognize that the paper feed cassette  21   a  (named “#1”) is to be used for printing of the print data RPD and that the original image represented by the print data RPD is to be printed on the sheet  24  stored in the paper feed cassette  21   a . The preview image SCPV, which is equal in size to the display area PE and smaller in size than the preview image BCPV, is efficiently displayed in the display area of the preview window PW. The width of the periphery image SV may be previously set arbitrarily as mentioned above, but is preferably set in consideration for the margin established in the printing section  22 .  
     [0126]FIG. 12 shows an example of the preview image DCPV being displayed. The preview image DCPV is equal in size to the display area PE, and contains the pattern image DV indicated by the identification information CC and used as the pattern of the preview image PV. In the preview image DCPV, a portion of an image (which is an combination of the preview image PV and the pattern image DV) presented within the display area PE which corresponds to the pattern image DV is not to be actually printed on the sheet  24 . The operator views the pattern image DV to thereby recognize which paper feed cassette  21  is to be used for printing of the original image (represented by the print data RPD) shown in FIG. 12. As an example, when the identification information CC is defined as shown in FIG. 3B, the pattern image DV displayed in “R (red)” allows the operator to recognize that the paper feed cassette  21   a  (named “#1 I”) is to be used for printing of the print data RPD and that the original image represented by the print data RPD is to be printed on the sheet  24  stored in the paper feed cassette  21   a . The preview image DCPV, which is equal in size to the display area PE and smaller in size than the preview image BCPV, is efficiently displayed in the display area of the preview window PW.  
     [0127] As described above, the controller  1  of the printing system  100  presents the preview display of the preview image CPV by using the identification information CC defined for the paper feed cassette  21  which feeds the sheet  24  for printing of the print data RPD thereon, thereby to allow the operator to easily grasp the correspondence between the print data RPD and the paper feed cassette  21 .  
     [0128] When the display format of the preview image PV is defined as “list” in the definition information PJ, the image creating section  175  repeatedly performs the operation in Steps S 63  and S 64  upon the plurality of print data RPD defined as the print data RPD to be preview-displayed in the definition information PJ, to create a plurality of preview images CPV. Then, the list display section  1761  of the image display section  176  scales down the plurality of preview images CPV so that the plurality of preview images CPV are placed within the preview window PW. The image display section  176  displays the plurality of scaled-down preview images CPV on the display section  12 .  
     [0129]FIG. 13 is an example of the preview images CPV being displayed in list form. The example shown in FIG. 13 is obtained when the definition information PJ specifies the print data RPD 1  and RPD 2  and defines the preview image display format as “list” and the identification display as “pattern,” and the correspondence table  1751  stores the information shown in FIG. 9.  
     [0130] A preview image DCPV 1  created from the print data RPD 1  and the identification information CC corresponding to the print data RPD 1  is displayed within the preview window PW. In this case, the correspondence table  1751  specifies that the sheet  24  is to be fed from the paper feed cassette  21   a  for printing of the print data RPD 1 . The identification information CC about the paper feed cassette  21   a  is defined as “R (red).” Thus, the pattern image DV for the preview image DCPV 1  is displayed in “R (red).” 
     [0131] Since the slip sheet insertion position is defined as “every job,” a slip sheet is to be inserted after the printing of the print data RPD 1 . Thus, the preview image ACPV is displayed in the next position after the preview image DCPV 1 . In this case, the correspondence table  1751  specifies that the sheet  24  is to be fed from the paper feed cassette  21   c  for insertion of the slip sheet. The identification information CC about the paper feed cassette  21   c  is defined as “B (blue).” Thus, the pattern image DV for the preview image ACPV is displayed in “B (blue).” 
     [0132] A preview image DCPV 2  created from the print data RPD 2  and the identification information CC corresponding to the print data RPD 2  is displayed in the next position after the preview image ACPV. In this case, the correspondence table  1751  specifies that the sheet  24  is to be fed from the paper feed cassette  21   b  for printing of the print data RPD 2 . The identification information CC about the paper feed cassette  21   b  is defined as “G (green).” Thus, the pattern image DV for the preview image DCPV 2  is displayed in “G (green).” 
     [0133] Displaying the plurality of preview images CPV in list form within the preview window PW in this manner allows the operator to easily recognize which paper feed cassette  21  is to feed the sheet  24  for printing of which print data RPD, when printing is to be performed based on the plurality of print data RPD.  
     [0134] Displaying the preview image ACPV allows the operator to recognize that the slip sheet is to be used and which paper feed cassette  21  is to feed the slip sheet. In other words, the operator can easily recognize which type of sheet  24  is to be used as the slip sheet.  
     [0135] Displaying the preview image ACPV between the preview images DCPV 1  and DCPV 2  allows the operator to recognize that the slip sheet is to be inserted between the printing of the print data RPD 1  and the printing of the print data RPD 2 . In other words, the operator can easily recognize the slip sheet insertion position.  
     [0136] After the preview display is presented, the processing proceeds to Step S 7  of FIG. 2. In Step S 7 , the operator judges whether or not the correspondences between the print data RPD and the paper feed cassettes  21  attain a satisfactory result. If the operator is not satisfied with the correspondences between the print data RPD and the paper feed cassettes  21  as a result of the preview display, the processing returns to Step S 3  to repeat the above-mentioned processes. If the operator is satisfied with the correspondences between the print data RPD and the paper feed cassettes  21 , the processing proceeds to Step S 8 .  
     [0137] In Step S 8 , when the operator inputs a command to start printing the print data RPD, the printing machine  2  carries out the printing of the print data RPD based on the specification information CJ. The printing machine  2  receives the control signal ACD sent from the controller  1 , whereby the control section  20  feeds the slip sheet.  
     [0138] As described above, the printing system  100  shown in FIG. 1 performs the operation shown in the flowcharts of FIGS. 2 and 6 to allow the operator who views the preview window PW to recognize on which type of sheet  24  the original image represented by the print data RPD is to be printed. This allows the operator to recognize whether or not a desired original image is to be reliably printed on a desired type of sheet prior to the printing process, to thereby produce the effect of solving the background art problems.  
     [0139] Although the identification information CC is defined for each of the paper feed cassettes  21  in the above description, the identification information CC may be defined only for a specific paper feed cassette  21 .  
     [0140] If the identification information CC is defined, for example, only for the paper feed cassette  21   c  for feeding the slip sheet, the preview display of only the preview image ACPV for the slip sheet is provided based on the identification information CC. This allows the operator to recognize, in particular, only the paper feed cassette  21  for feeding the slip sheet. This produces the effect of facilitating the judgment about the feed of the slip sheet.  
     [0141] Although information about color is defined as the identification information CC in the above description, information about the number or name of each paper feed cassette  21  or about the type of sheets  24  stored in each paper feed cassette  21  may be used as the identification information CC. In other words, any information which allows the operator to identify the paper feed cassettes  21  may be used as the identification information CC.  
     [0142]FIG. 14A shows an example of the correspondence table  1751  when information about the type of sheets  24  stored in each of the paper feed cassettes  21  is used as the identification information CC. FIG. 14B shows an example of the preview images DCPV displayed in list form, based on the correspondence table  1751  shown in FIG. 14A. Displaying the preview images CPV as shown in FIG. 14B allows the operator to identify the type of sheet  24  on which each of the print data RPD is to be printed at a glance. This produces the effect of allowing the operator to more easily recognize whether or not a desired original image is to be reliably printed on a desired type of sheet. In such a modification, the display format of the identification information CC for the preview images CPV may, of course, be the “background” or the “periphery.” 
     [0143] In the above description, the preview image CPV is created by combining the background image BV, periphery image SV or pattern image DV created from the identification information CC with the preview image PV. However, other techniques may be used to create a preview image CPV.  
     [0144] As an example, the image creating section  175  may further write the background image BV, the periphery image SV or the pattern image DV into the display area PE obtained from the size of the sheet  24 , and thereafter performs a pixel skipping or scale-down process on the original image represented by the print data RPD, thereby to create the preview image PV. Such a technique for combination also creates a preview image CPV similar to that described above.  
     [0145] In the description hereinabove, it is assumed that the print data RPD is to be printed on the single sheet  24 . The present invention, however, is applicable to the printing of the single print data RPD on a plurality of sheets  24  or the printing of a plurality of print data RPD on a plurality of sheets  24 , respectively, in the printing system  100 .  
     [0146] Additionally, the printing machine  2  includes the three paper feed cassettes  21  in the above description. However, the present invention is applicable to the printing machine  2  including two paper feed cassettes  21  or at least four paper feed cassettes  21 .  
     [0147] Further, the printing of the print data RPD on the sheet  24  is described hereinabove as single-sided printing. However, the present invention is applicable to double-sided printing for printing two print data RPD on opposite sides of the single sheet  24 .  
     [0148] While the invention has been described in detail, the foregoing description is in all aspects illustrative and not restrictive. It is understood that numerous other modifications and variations can be devised without departing from the scope of the invention.