Patent Publication Number: US-9417590-B2

Title: Printing control device, printing control method, and computer-readable storage medium for gloss control during post-processing

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application claims priority to and incorporates by reference the entire contents of Japanese Patent Application No. 2012-090581 filed in Japan on Apr. 11, 2012 and Japanese Patent Application No. 2013-060902 filed in Japan on Mar. 22, 2013. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a printing control device, a printing control method, and a computer-readable storage medium. 
     2. Description of the Related Art 
     Conventionally, there have been developed image forming apparatuses provided with a clear toner, which is a colorless toner including no color material in addition to four color toners of CMYK. A toner image formed with such a clear toner is fixed on a recording medium, such as a transfer sheet, on which an image is formed with CMYK toners. As a result, a visual effect and a tactile effect (referred to as a surface effect) are produced on the surface of the recording medium. The surface effect to be produced differs depending on the type of the toner image formed with the clear toner and the way to fix the toner image. Some surface effects simply provide gloss, whereas some surface effects suppress gloss. Other examples of the surface effects may include: a surface effect applied not to the entire surface but to a part thereof; a surface effect that forms a texture and a watermark with a clear toner; a surface effect that provides surface protection; and a surface effect produced by a dedicated post-processing device, such as a glosser and a low-temperature fixing device, performing post-processing besides by fixing control. Japanese Patent Application Laid-open No. 2009-058941, for example, discloses an image forming apparatus that can change forming conditions for forming a latent image of a transparent toner image. 
     Japanese Patent Application Laid-open No. 2010-152129, for example, discloses an image forming apparatus that performs control such that the frequency of fixing processing related to an electrophotography process differs for a divided image divided into a plurality of parts in units in which the level of gloss is to be changed. 
     If a print request is received in which a plurality of surface effects to be produced by a plurality of types of post-processing are present in a single page and if the post-processing device cannot perform the types of post-processing simultaneously in the single page, the conventional image forming apparatus cannot control the post-processing device so as to produce the surface effects properly. 
     Therefore, there is a need to provide a printing control device, a printing control method, and a computer-readable storage medium that can accept a print request including a plurality of surface effects to be produced by a plurality of types of post-processing incapable of being performed simultaneously by a post-processing device in a single page and control the post-processing device so as to produce the surface effects properly. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to at least partially solve the problems in the conventional technology. 
     According to an embodiment, there is provided a printing control device that includes a data acquiring unit configured to acquire gloss-control plane data that indicates a plurality of types of surface effects to be applied to one page of a recording medium and areas to which the respective types of surface effects are to be applied in the one page of the recording medium. The types of surface effects correspond respectively to a plurality of types of post-processing that are incapable of being simultaneously performed on the one page of the recording medium by a post-processing device that performs post-processing for a clear toner transferred onto the recording medium. The printing control device also includes a determining unit configured to determine one of the types of post-processing to be preferentially performed on the one page of the recording medium, based on priority information that indicates which type of post-processing is to be preferentially performed. 
     According to another embodiment, there is provided a printing control method that includes acquiring gloss-control plane data that indicates a plurality of types of surface effects to be applied to one page of a recording medium and areas to which the respective types of surface effects are to be applied in the one page of the recording medium, the types of surface effects corresponding respectively to a plurality of types of post-processing that are incapable of being simultaneously performed on the one page of the recording medium by a post-processing device that performs post-processing for a clear toner transferred onto the recording medium; and determining one of the types of post-processing to be preferentially performed on the one page of the recording medium, based on priority information that indicates which type of post-processing is to be preferentially performed. 
     According to still another embodiment, there is provided a non-transitory computer-readable storage medium with an executable program stored thereon. The program instructs a computer to perform acquiring gloss-control plane data that indicates a plurality of types of surface effects to be applied to one page of a recording medium and areas to which the respective types of surface effects are to be applied in the one page of the recording medium, the types of surface effects corresponding respectively to a plurality of types of post-processing that are incapable of being simultaneously performed on the one page of the recording medium by a post-processing device that performs post-processing for a clear toner transferred onto the recording medium; and determining one of the types of post-processing to be preferentially performed on the one page of the recording medium, based on priority information that indicates which type of post-processing is to be preferentially performed. 
     The above and other objects, features, advantages and technical and industrial significance of this invention will be better understood by reading the following detailed description of presently preferred embodiments of the invention, when considered in connection with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an exemplary block diagram of a configuration of a printing control system according to a first embodiment of the present invention; 
         FIG. 2  is a schematic of an example of color plane image data; 
         FIG. 3  is an exemplary schematic of the types of surface effects related to the presence of gloss; 
         FIG. 4  is a schematic illustrating gloss-control plane image data as an image; 
         FIG. 5  is a schematic of an example of clear plane image data; 
         FIG. 6  is a block diagram of an exemplary schematic configuration of a host device; 
         FIG. 7  is a schematic of an exemplary screen displayed by an image processing application; 
         FIG. 8  is a schematic of another exemplary screen displayed by the image processing application; 
         FIG. 9  is a schematic of an example of a density value selection table; 
         FIG. 10  is a conceptual schematic of an exemplary structure of print data; 
         FIG. 11  is an exemplary block diagram of a functional configuration of a DFE; 
         FIG. 12  is an exemplary schematic of a data structure of a surface effect selection table; 
         FIG. 13  is an exemplary block diagram of a functional configuration of a clear processing unit; 
         FIG. 14  is a flowchart of an exemplary operation of a clear-toner plane processing unit; 
         FIG. 15  is a schematic of an example of a list (results of acquisition of surface effect information) to which the clear-toner plane processing unit adds a surface effect of the gloss-control plane; 
         FIG. 16  is a flowchart of an exemplary operation of a determining unit; 
         FIG. 17  is an exemplary conceptual schematic of a configuration of an MIC; 
         FIG. 18  is a schematic of results of printing performed by the printing control system when gloss-control plane data indicates a plurality of types of post-processing incapable of being performed simultaneously by a glosser in one page; 
         FIG. 19  is a schematic of a menu screen used for changing the surface effect selection table displayed by a UI; 
         FIG. 20  is an exemplary block diagram of a configuration of a printing control system according to a second embodiment of the present invention; 
         FIG. 21  is a sequence diagram of the whole process of generation processing of a clear toner plane according to the second embodiment; and 
         FIG. 22  is a block diagram of a hardware configuration of the host device, the DFE, and a server device. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Exemplary embodiments of a device, a system, a method, and a computer program for controlling printing according to the present invention are described below in greater detail with reference to the accompanying drawings. 
     First Embodiment 
     A configuration of a printing control system (an image forming system) according to a first embodiment of the present invention will be described with reference to  FIG. 1 . The printing control system according to the present embodiment includes a printing control device (digital front end: DFE)  50  (hereinafter, referred to as a “DFE  50 ”), an interface controller (mechanism I/F controller: MIC)  60  (hereinafter, referred to as an “MIC  60 ”), a printer  70 , and a glosser  80  serving as a post-processing device connected in series. The DFE  50  communicates with the printer  70  via the MIC  60  and controls formation of an image in the printer  70 . Furthermore, the DFE  50  is connected to a host device  10 , such as a personal computer (PC), and receives image data from the host device  10 . The DFE  50  uses the image data to generate image data used for forming toner images corresponding to CMYK toners and a clear toner by the printer  70 . The DFE  50  then transmits the image data thus generated to the printer  70  via the MIC  60 . The printer  70  is provided with at least CMYK toners and a clear toner. The printer  70  is further provided with an image forming unit including a photosensitive element, a charger, a developing unit, and a photosensitive-element cleaning unit, an exposing unit, and a fixing unit for each toner. 
     The clear toner is a transparent (colorless) toner including no color material. Being transparent (colorless) means that the transmittance is equal to or larger than 70%, for example. 
     The printer  70  outputs a light beam from the exposing unit correspondingly to image data transmitted from the DFE  50  via the MIC  60  to form a toner image corresponding to each toner on the photosensitive element. The printer  70  then transfers the toner image onto a sheet serving as a recording medium and fixes the toner image thereon at temperature within a predetermined range (normal temperature) and pressure by the fixing unit. Thus, an image is formed on the sheet. The sheet is given just as an example of the recording medium, and the recording medium is not limited thereto. The recording medium may be a piece of synthetic paper or a piece of plastic paper, for example. 
     The glosser  80  is controlled to be turned ON or OFF in accordance with ON-OFF information specified by the DFE  50 . If the glosser  80  is turned ON, the glosser  80  presses an image formed on a sheet by the printer  70  at high temperature and high pressure. Subsequently, the glosser  80  cools the sheet on which the image is formed and removes the sheet from its main body. This operation evenly compresses the total amount of adhered toners on pixels to which a toner of equal to or larger than a predetermined amount is adhered in the whole image formed on the sheet. In other words, the glosser  80  performs post-processing for applying a surface effect in page units. 
     The image data (document data) received from the host device  10  will now be described. In the host device  10 , image data is generated by an image processing application (an image processing unit  120 , a plane data generating unit  122 , a print data generating unit  123 , and other units, which will be described later) installed in advance and is transmitted to the DFE  50 . Such an image processing application can deal with image data of a specific color plane in contrast to image data that specifies a value of density (referred to as a density value) of each color in each color plane, such as an RGB plane and a CMYK plane, for each pixel. The specific color plane is image data used for adhering a toner and an ink of a specific color, such as white, gold, and silver, in addition to basic colors, such as CMYK and RGB. The specific color plane is data used by a printer provided with a toner and an ink of such a specific color. To improve the color reproducibility, R may be added to the basic colors of CMYK or Y may be added to the basic colors of RGB in the specific color plane. Typically, a clear toner has been considered as one of the specific colors. 
     In the present embodiment, the clear toner serving as a specific color is used to form a surface effect, which is a visual or tactile effect to be applied to a sheet, and to form a transparent image, such as a watermark and a texture, other than the surface effect described above. 
     Therefore, in addition to image data of a color plane, the image processing application of the host device  10  generates at least one of image data of a gloss-control plane and image data of a clear plane as image data of a specific color plane in accordance with a user&#39;s specification from the image data thus received. 
     The image data of the color plane is image data that specifies the density value of a color of RGB and CMYK for each pixel, for example. In the image data of the color plane, one pixel is represented by 8-bits in accordance with the user&#39;s specification of a color.  FIG. 2  is a view for explaining an example of the image data of the color plane. In  FIG. 2 , a density value corresponding to a color specified by the user via the image processing application is defined for each drawn object, such as “A”, “B”, and “C”. 
     The image data of the gloss-control plane is image data used to perform control for adhering the clear toner correspondingly to a surface effect, which is a visual or tactile effect applied to a sheet, and specifies an area to which the surface effect is to be applied and the type of the surface effect. 
     Similarly to the color plane of RGB and CMYK, for example, each pixel in the gloss-control plane is represented by 8-bits with a density value ranging from “0” to “255”. The density values are associated with the types of surface effects (the density values may be represented by 16-bits or 32-bits or by 0 to 100%). The same value is set for areas to which the same surface effect is desired to be applied regardless of the density of the clear toner to be actually adhered. Therefore, even if there is no data indicating the areas, the areas can be readily specified from the image data as needed. In other words, the gloss-control plane indicates the type of a surface effect and the area to which the surface effect is to be applied (data indicating the area may be provided separately). 
     The host device  10  sets the type of a surface effect for a drawn object specified by the user via the image processing application as a density value serving as a gloss-control value for each drawn object, thereby generating image data of the gloss-control plane (gloss-control plane image data) in a vector format. 
     Each pixel constituting the image data of the gloss-control plane corresponds to each pixel in the image data of the color plane. The density value of each pixel corresponds to the pixel value in each image data. Both the image data of the color plane and the image data of the gloss-control plane are formed in page units. 
     The types of surface effects are roughly classified into a surface effect related to the presence of gloss, surface protection, a watermark indicating information, and a texture, for example. The surface effects related to the presence of gloss are roughly classified into four as illustrated in  FIG. 3 . The four types of surface effects are mirror-surface glossy (PG: Premium Gloss), solid glossy (G: Gloss), halftone matte (M: Matte), and delustered (PM: Premium Matte) in descending order of degrees of gloss (glossiness), for example. Hereinafter, the mirror-surface glossy, the solid glossy, the halftone matte, and the delustered may be referred to as premium gloss (PG), gloss (G), matte (M), and premium matte (PM), respectively. 
     Premium gloss and gloss provide a higher gloss, whereas matte and premium matte suppress gloss. In particular, premium matte provides glossiness lower than that of plain paper. In  FIG. 3 , premium gloss indicates glossiness Gs of equal to or higher than 80, gloss indicates solid glossiness in a primary color or a secondary color, matte indicates glossiness in a primary color and halftone dots of 30%, and premium matte indicates glossiness of equal to or lower than 10. The deviation in the glossiness is represented by AGs and is equal to or smaller than 10. For these types of surface effects, a higher density value is associated with a surface effect that provides a higher gloss, whereas a lower density value is associated with a surface effect that suppresses gloss. A density value in the middle thereof is associated with a surface effect, such as a watermark and a texture. Examples of the watermark may include a character and a background pattern. The texture is formed of characters and patterns and can produce a tactile effect besides a visual effect. A pattern of a stained glass can be formed with the clear toner, for example. Premium gloss and gloss also serve as surface protection. The user specifies the area to which the surface effect is to be applied in an image represented by image data to be processed and the type of the surface effect to be applied to the area via the image processing application. The host device  10  that exerts the image processing application sets a density value corresponding to the surface effect specified by the user for the drawn object corresponding to the area specified by the user, thereby generating image data of the gloss-control plane. The correspondence relation between the density values and the types of surface effects will be described later in detail. 
       FIG. 4  is a view for explaining an example of the image data of the gloss-control plane. In the example of the gloss-control plane in  FIG. 4 , the user applies the surface effect “premium gloss (PG)” to a drawn object of “ABC”, applies the surface effect “gloss (G)” to a drawn object of “a rectangular figure”, and applies the surface effect “matte (M)” to a drawn object of “a circular figure”. The density value set for each surface effect is a density value defined correspondingly to the type of each surface effect in a density value selection table (refer to  FIG. 9 ), which will be described later. 
     The image data of the clear plane is image data specifying a transparent image, such as a watermark and a texture, other than the surface effects described above.  FIG. 5  is a view for explaining an example of the image data of the clear plane. In the example of  FIG. 5 , the user specifies a watermark “Sale”. 
     As described above, the image data of the gloss-control plane and the clear plane, which is image data of the specific color plane, is generated as planes different from that of the image data of the color plane by the image processing application of the host device  10 . The image data of the color plane, the image data of the gloss-control plane, and the image data of the clear plane are generated in a portable document format (PDF). These pieces of image data of the planes in the PDF are integrated and generated as document data. The data format of the image data of each plane is not limited to the PDF and may be an arbitrary format. 
     The host device  10  that generates the image data of each plane will now be described in detail.  FIG. 6  is a block diagram of an exemplary schematic configuration of the host device  10 . As illustrated in  FIG. 6 , the host device  10  includes an I/F  11 , a storage unit  12 , an input unit  13 , a display unit  14 , and a control unit  15 . The I/F  11  is an interface device that communicates with the DFE  50 . The storage unit  12  is a storage medium, such as a hard disk drive (HDD) and a memory, that stores therein various types of data. The input unit  13  is an input device through which the user performs various input operations and is formed of a keyboard and a mouse, for example. The display unit  14  is a display device that displays various screens and is formed of a liquid crystal panel, for example. 
     The control unit  15  is a computer collectively controlling the host device  10  and including a central processing unit (CPU), a read-only memory (ROM), and a random access memory (RAM), for example. As illustrated in  FIG. 6 , the control unit  15  mainly includes an input control unit  124 , the image processing unit  120 , a display control unit  121 , the plane data generating unit  122 , and the print data generating unit  123 . The input control unit  124  and the display control unit  121  among these units are executed by the CPU of the control unit  15  reading a computer program of an operating system stored in the ROM or the like and loading and executing the computer program on the RAM. The image processing unit  120 , the plane data generating unit  122 , and the print data generating unit  123  are executed by the CPU of the control unit  15  reading a computer program of the image processing application stored in the ROM or the like and loading and executing the computer program on the RAM. The plane data generating unit  122  is provided as a plug-in function installed in the image processing application, for example. At least a part of these units may be executed by an individual circuit (hardware). 
     The input control unit  124  receives various types of input from the input unit  13  and controls the input. By operating the input unit  13 , for example, the user can input image specification information for specifying an image to which a surface effect is to be applied, that is, image data of the color plane (hereinafter, it may be referred to as a “target image”) among various images (e.g., photos, characters, figures, and images obtained by synthesizing these elements) stored in the storage unit  12 . The method for inputting the image specification information is not limited thereto, and an arbitrary method may be employed. 
     The display control unit  121  controls display of various types of information on the display unit  14 . In the present embodiment, if the input control unit  124  receives image specification information, the display control unit  121  reads an image specified by the image specification information from the storage unit  12  and controls the display unit  14  to display the image thus read on the screen. 
     By operating the input unit  13  while checking the target image displayed on the display unit  14 , the user can input specification information for specifying an area to which a surface effect is to be applied and the type of the surface effect. The method for inputting the specification information is not limited thereto, and an arbitrary method may be employed. 
     More specifically, the display control unit  121  causes the display unit  14  to display a screen illustrated in  FIG. 7 , for example.  FIG. 7  is an example of a screen displayed when a plug-in is incorporated into Illustrator (registered trademark) marketed by Adobe Systems (R). The screen illustrated in  FIG. 7  displays an image indicated by target image data (image data of the color plane) to be processed. If the user presses a marker add button through the input unit  13  to perform an input operation for specifying an area to which a surface effect is desired to be applied, the area to which the surface effect is to be applied is specified. The user performs such an input operation on all the areas to which a surface effect is to be applied. The display control unit  121  of the host device  10  then causes the display unit  14  to display a screen illustrated in  FIG. 8  for each area thus specified, for example. The screen illustrated in  FIG. 8  displays an image of each area specified as an area to which a surface effect is to be applied. If the user performs an input operation for specifying the type of the surface effect desired to be applied to the image through the input unit  13 , the type of the surface effect to be applied to the area is specified. The types of surface effects of premium gloss and gloss illustrated in  FIG. 3  are denoted as “inverse mask” in  FIG. 8 . The effects other than premium gloss and gloss illustrated in  FIG. 3  are denoted as stained glass, parallel line pattern, mesh pattern, mosaic style, matte, and halftone in  FIG. 8 . Thus, the screen indicates that each surface effect can be specified. 
     Referring back to  FIG. 6 , the image processing unit  120  performs various types of image processing on the target image based on an instruction received from the user through the input unit  13 . 
     The plane data generating unit  122  generates image data of the color plane, image data of the gloss-control plane, and image data of the clear plane. In other words, if the input control unit  124  receives specification of a color made by the user for a drawn object of a target image, the plane data generating unit  122  generates image data of the color plane in accordance with the specification of a color. 
     If the input control unit  124  receives specification of a transparent image other than the surface effect, such as a watermark and a texture, and of an area in which the transparent image is to be formed, the plane data generating unit  122  generates image data of the clear plane for specifying the transparent image and the area in which the transparent image is to be formed on a sheet in accordance with the specification made by the user. 
     If the input control unit  124  receives specification information (an area to which a surface effect is to be applied and the type of the surface effect), the plane data generating unit  122  generates image data of the gloss-control plane capable of specifying the area to which the surface effect is to be applied on a sheet and the type of the surface effect based on the specification information. The plane data generating unit  122  generates image data of the gloss-control plane for specifying the area to which the surface effect represented by a gloss-control value is to be applied in units of drawn objects in the image data of the target image. 
     The storage unit  12  stores therein the density value selection table storing therein the type of a surface effect specified by the user and the density value of the gloss-control plane corresponding to the type of the surface effect.  FIG. 9  is a schematic of an example of the density value selection table. In the example of  FIG. 9 , the density value of the gloss-control plane corresponding to an area for which the surface effect “PG” (premium gloss) is specified by the user is “98%”, the density value of the gloss-control plane corresponding to an area for which “G” (gloss) is specified is “90%”, the density value of the gloss-control plane corresponding to an area for which “M” (matte) is specified is “16%”, and the density value of the gloss-control plane corresponding to an area for which “PM” (premium matte) is specified is “6%”. 
     The density value selection table is a part of data of a surface effect selection table (described later) stored in the DFE  50 . The control unit  15  acquires the surface effect selection table at a predetermined timing to generate the density value selection table from the surface effect selection table thus acquired and stores the density value selection table in the storage unit  12 . The surface effect selection table may be stored in a storage server (cloud) on a network, such as the Internet. In this case, the control unit  15  acquires the surface effect selection table from the server and generates the density value selection table from the surface effect selection table thus acquired. The surface effect selection table stored in the DFE  50  needs to be the same as the surface effect selection table stored in the storage unit  12 . 
     Referring back to  FIG. 6 , the plane data generating unit  122  sets the density value (gloss-control value) of a drawn object for which a certain surface effect is specified by the user to a value corresponding to the type of the surface effect while referring to the density value selection table illustrated in  FIG. 9 , thereby generating image data of the gloss-control plane. An assumption is made that the user specifies to apply “PG” to the area displayed as “ABC”, apply “G” to the area of the rectangular figure, and apply “M” to the area of the circular figure among the target images serving as the image data of the color plane illustrated in  FIG. 2 , for example. In this case, the plane data generating unit  122  sets the density value of the drawn object for which “PG” is specified by the user (“ABC”) to “98%”, sets the density value of the drawn object for which “G” is specified (“the rectangular figure”) to “90%”, and sets the density value of the drawn object for which “M” is specified (“the circular figure”) to “16%”, thereby generating image data of the gloss-control plane. The image data of the gloss-control plane generated by the plane data generating unit  122  is data in a vector format represented as a set of drawn objects indicating coordinates of points, parameters of equations of lines and planes connecting the points, fill, and special effects, for example.  FIG. 4  is a schematic illustrating the image data of the gloss-control plane as an image. The plane data generating unit  122  generates document data by integrating the image data of the gloss-control plane, the image data of the target image (image data of the color plane), and the image data of the clear plane and transmits the document data to the print data generating unit  123 . 
     The print data generating unit  123  generates print data based on the document data. The print data includes the image data of the target image (image data of the color plane), the image data of the gloss-control plane, the image data of the clear plane, and a job command, such as setting of a printer, setting for intensive printing, and setting for duplex printing, issued to the printer.  FIG. 10  is a conceptual schematic of an exemplary structure of the print data. While job definition format (JDF) is used as a job command in the example of  FIG. 10 , the job command is not limited thereto. The JDF illustrated in  FIG. 10  is a command for specifying “single-sided printing and stapling” as the setting for intensive printing. The print data may be converted into a page description language (PDL), such as PostScript, or may remain in the PDF as long as the DFE  50  is compatible with the PDF. 
     The functional configuration of the DFE  50  will now be described. As illustrated in  FIG. 11 , the DFE  50  includes a data acquiring unit  58 , a rendering engine  51 , an si1 unit  52 , a tone reproduction curve (TRC) unit  53 , an si2 unit  54 , a halftone engine  55 , a clear processing unit  56 , an si3 unit  57 , and the surface effect selection table (not illustrated). 
     The data acquiring unit  58  acquires image data (e.g. the print data illustrated in  FIG. 10 ) transmitted from the host device  10 . In other words, the image data acquired by the data acquiring unit  58  includes gloss-control plane data. 
     The rendering engine  51 , the si1 unit  52 , the TRC unit  53 , the si2 unit  54 , the halftone engine  55 , the clear processing unit  56 , and the si3 unit  57  are executed by a control unit of the DFE  50  executing various computer programs stored in a main memory or an auxiliary memory. The si1 unit  52 , the si2 unit  54 , and the si3 unit  57  have a function to separate image data and a function to integrate image data. The surface effect selection table is stored in the auxiliary memory, for example. 
     The rendering engine  51  receives image data transmitted from the host device  10  via the data acquiring unit  58 . The rendering engine  51  interprets the language of the image data thus received to convert the image data expressed in a vector format into image data expressed in a raster format and converts a color space expressed in an RGB format or the like into a color space in a CMYK format. As a result, the rendering engine  51  outputs pieces of 8-bit image data of CMYK color planes, an 8-bit gloss-control plane, and an 8-bit clear plane. The rendering engine  51  may output no clear plane. 
     The si1 unit  52  outputs the pieces of 8-bit image data of CMYK to the TRC unit  53  and outputs the 8-bit gloss-control plane (and the 8-bit clear plane) to the clear processing unit  56 . The DFE  50  converts image data of the gloss-control plane in a vector format received from the host device  10  into image data in a raster format. As a result, the DFE  50  sets the type of the surface effect for the drawn object specified by the user via the image processing application as a density value in pixel units, thereby outputting image data of the gloss-control plane. 
     The TRC unit  53  receives the pieces of 8-bit image data of CMYK via the si1 unit  52 . The TRC unit  53  performs gamma correction on the image data thus received using a gamma curve of 1D_LUT (one-dimensional look-up table) generated by calibration. Examples of the image processing include control on the total amount of toner besides the gamma correction. The total amount control is processing for limiting the pieces of 8-bit image data of CMYK on which the gamma correction is performed for the reason of limits on the amount of toner capable of being supplied by the printer  70  to one pixel on a recording medium. If an image is printed in disregard of the total amount control, the image quality deteriorates because of poor transfer and poor fixing. In the present embodiment, the explanation is made of the related gamma correction alone. 
     The si2 unit  54  outputs the pieces of 8-bit image data of CMYK on which the gamma correction is performed by the TRC unit  53  to the clear processing unit  56  as data used for generating an inverse mask (which will be described later). The halftone engine  55  receives the pieces of 8-bit image data of CMYK on which the gamma correction is performed via the si2 unit  54 . To output the pieces of image data thus received to the printer  70 , the halftone engine  55  performs halftone processing for converting the pieces of image data into pieces of 2-bit image data of CMYK, for example. The halftone engine  55  then outputs the pieces of 2-bit image data of CMYK obtained by performing the halftone processing. The 2-bit data format is given just as an example, and the data format is not limited thereto. 
     The clear processing unit  56  receives the 8-bit gloss-control plane (and the 8-bit clear plane) converted by the rendering engine  51  via the sit unit  52  and receives the pieces of 8-bit image data of CMYK on which the gamma correction is performed by the TRC unit  53  via the si2 unit  54 . The clear processing unit  56  uses the gloss-control plane (and the 8-bit clear plane) thus received and refers to the surface effect selection table, which will be described later, thereby determining the surface effect corresponding to the density value (pixel value) of each pixel constituting the gloss-control plane. In accordance with the determination, the clear processing unit  56  determines whether to turn ON or OFF the glosser  80 . In addition, the clear processing unit  56  uses the pieces of 8-bit image data of CMYK thus received to generate an inverse mask or a solid mask as appropriate. Thus, the clear processing unit  56  generates 2-bit image data of the clear-toner plane to which the clear toner is to be adhered as appropriate. Based on the result of determination of the surface effect, the clear processing unit  56  generates and outputs image data of the clear-toner plane to be used in the printer  70  as appropriate. In addition, the clear processing unit  56  outputs ON-OFF information corresponding to “ON” or “OFF” of the glosser  80 . 
     The inverse mask makes the total amount of adhered CMYK toners and an adhered clear toner uniform on pixels constituting a target area to which the surface effect is to be applied. Specifically, the inverse mask is generated by adding all the density values of the pixels constituting the target area in the image data of the CMYK plane and subtracting the value thus added from a predetermined value. The inverse mask, for example, is expressed by Equation (1):
 
 Clr= 100−( C+M+Y+K )  (1)
 
     in the case of Clr&lt;0, Clr=0 is satisfied. 
     In Equation (1), Clr, C, M, Y, and K represent the density rate converted from the density value of each pixel for the clear toner and each toner of C, M, Y, and K, respectively. In other words, by using Equation (1), the total amount of adhered toners obtained by adding the amount of the adhered clear toner to the total amount of the adhered toners of C, M, Y, and K is made 100% for all the pixels constituting the target area to which the surface effect is to be applied. If the total amount of the adhered toners of C, M, Y, and K is equal to or larger than 100%, no clear toner is to be adhered, and the density rate of the clear toner is made 0%. This is because the part where the total amount of the adhered toners of C, M, Y, and K exceeds 100% is made smooth by fixing processing. By making the total amount of the adhered toner on all the pixels constituting the target area to which the surface effect is to be applied equal to or larger than 100% in this manner, it is possible to eliminate unevenness on the surface caused by difference in the total amount of the adhered toner in the target area. As a result, gloss is generated by specular reflection of light. Because some inverse masks are derived from equations other than Equation (1), there can be a plurality of types of inverse masks. 
     The inverse mask, for example, may cause the clear toner to uniformly adhere to the pixels. In this case, the inverse mask is also referred to as a solid mask and is expressed by Equation (2):
 
 Clr= 100  (2)
 
     Because some of the pixels to which the surface effect is to be applied may be associated with a density rate other than 100%, there can be a plurality of types of solid masks. 
     Alternatively, the inverse mask may be derived by multiplication of the background exposure rate of each color, for example. In this case, for example, the inverse mask is expressed by Equation (3):
 
 Clr= 100×{(100 −C )/100}×{(100 −M )/100}×{(100 −Y )/100}×{(100 −K )/100}  (3)
 
     In Equation (3), (100−C)/100 represents the background exposure rate of C, (100−M)/100 represents the background exposure rate of M, (100−Y)/100 represents the background exposure rate of Y, and (100−K)/100 represents the background exposure rate of K. 
     Still alternatively, the inverse mask may be derived by a method assuming that halftone dots having the largest area ratio achieve the smoothness. In this case, for example, the inverse mask is expressed by Equation (4):
 
 Clr= 100−max( C,M,Y,K )  (4)
 
     In Equation (4), max(C,M,Y,K) indicates that the density value of a color having the largest density value among CMYK is a representative value. 
     In other words, the inverse mask may be expressed by any one of Equation (1) to Equation (4). 
     The surface effect selection table indicates correspondence relation between the density values serving as gloss-control values indicating surface effects and the types of the surface effects. In addition, the surface effect selection table indicates correspondence relation among control information related to the post-processing device in accordance with the configuration of the printing control system, the image data of the clear-toner plane used in the printer  70 , and the image data of the clear-toner plane used in the post-processing device. While the image forming system can have various configurations, the image forming system according to the present embodiment has a configuration in which the glosser  80  serving as the post-processing device is connected to the printer  70 . Therefore, the control information related to the post-processing device in accordance with the configuration of the image forming system corresponds to the ON-OFF information indicating “ON” or “OFF” of the glosser  80 . 
       FIG. 12  is an exemplary schematic of a data structure of the surface effect selection table. The surface effect selection table can indicate the correspondence relation among the control information related to the post-processing device, the image data of the clear-toner plane, the density values, and the types of surface effects for each of different configurations of the printing control system (image forming system).  FIG. 12  illustrates a data structure corresponding to the configuration of the printing control system according to the present embodiment. In the correspondence relation between the types of surface effects and the density values illustrated in  FIG. 12 , the types of surface effects are associated with respective ranges of the density values. Furthermore, the types of surface effects are associated with respective rates of density (density rates) each converted from a value (a representative value) serving as a representative of a range of density values in units of 2%. Specifically, surface effects for providing gloss (premium gloss and gloss) are associated with ranges of density values (from “212” to “255”) having a density rate of equal to or larger than 84%. By contrast, a surface effect for suppressing gloss (matte) is associated with ranges of density values (from “23” to “43”) having a density rate of equal to or smaller than 16%. Furthermore, surface effects, such as a texture, a background pattern, and a watermark, are associated with ranges of density values having density rates of 20% to 80%. 
     More specifically, premium gloss (PG) is associated with pixel values of “238” to “255” as the surface effect. In these pixel values, three different types of premium gloss are associated with respective ranges of pixel values of “238” to “242”, pixel values of “243” to “247”, and pixel values of “248” to “255”. Gloss (G) is associated with pixel values of “212” to “232”. In these pixel values, four different types of gloss are associated with respective ranges of pixel values of “212” to “216”, pixel values of “217” to “221”, pixel values of “222” to “227”, and pixel values of “228” to “232”. Matte (M) is associated with pixel values of “23” to “43”. In these pixel values, four different types of matte are associated with respective ranges of pixel values of “23” to “28”, pixel values of “29” to “33”, pixel values of “34” to “38”, and pixel values of “39” to “43”. These different types of the same surface effect are different from one another in equations for deriving image data of the clear-toner plane to be used in the printer  70 . The printer main body and the post-processing device each perform the same operation. No surface effect is associated with a density value of “0”. 
     In the surface effect selection table ( FIG. 12 ), the pixel values, the surface effects, and the ON-OFF information indicating “ON” or “OFF” of the glosser  80  are associated with one another. The ON-OFF information indicates the optimum post-processing for each surface effect. Specifically, the surface effect selection table indicates that the glosser  80  is turned ON if the surface effect is premium gloss, that the glosser  80  is turned OFF if the surface effect is gloss, tactile pattern, or matte, and that “ON” or “OFF” of the glosser  80  is not specified if the surface effect is user definition, watermark character, or background pattern, or if no surface effect is to be applied. 
     The clear processing unit  56  refers to the surface effect selection table to determine the surface effect associated with each pixel value indicated by the gloss-control plane. In addition, the clear processing unit  56  determines whether to turn ON or OFF the glosser  80  and determines the type of image data of the clear-toner plane to be used in the printer  70 . The clear processing unit  56  determines whether to turn ON or OFF the glosser  80  for each page. Subsequently, as described above, the clear processing unit  56  generates and outputs the image data of the clear-toner plane based on the result of the determination as appropriate. In addition, the clear processing unit  56  outputs the ON-OFF information of the glosser  80 . 
       FIG. 13  illustrates an example of a functional configuration of the clear processing unit  56 . A clear-toner plane processing unit  563  performs clear-toner plane processing for generating a clear-toner plane based on gloss-control plane data acquired from a gloss-control plane storage unit  560 , clear plane data acquired from a clear plane storage unit  561 , and a surface effect table acquired from a table storage unit  562 . The clear-toner plane processing unit  563  then stores the result in a clear-toner plane storage unit  569 . While performing the clear-toner plane processing, the clear-toner plane processing unit  563  stores information of the surface effect applied to the clear-toner plane in a surface effect information storage unit  564 . When the clear-toner plane processing is completed on the whole page, the surface effect information storage unit  564  stores therein all the information of the surface effects applied to the page. Based on the information, a determining unit  567  determines post-processing control. 
     Because the glosser  80  performs processing in page units, the glosser  80  cannot achieve turning ON and OFF of the processing simultaneously on a single page. Therefore, if there are a plurality of surface effects to be produced by post-processing incapable of being performed simultaneously by the glosser  80  (turning ON and OFF of the processing) in a single page, the determining unit  567  determines post-processing to be preferentially performed by the glosser  80  in page units based on priority information so as to produce the surface effects properly in page units. The priority information indicates which post-processing is to be preferentially performed by the glosser  80  in page units between types of post-processing for which the glosser  80  is turned ON or OFF. Specifically, the priority information is determined in advance so as to produce surface effects properly based on the surface effect selection table ( FIG. 12 ), for example. The priority information includes selection methods of post-processing control, such as “fixed to OFF” for constantly turning OFF the glosser  80 , “prioritize ON” for prioritizing a surface effect for which the glosser  80  is turned ON, and “prioritize OFF” for prioritizing a surface effect for which the glosser  80  is turned OFF, for example. 
     The clear processing unit  56  may include a user interface (UI)  565  and a setting storage unit  566 , for example, and receive input for setting the priority information via an input unit included in the UI  565 . The setting storage unit  566  stores therein setting of the priority information received via the UI  565 . Alternatively, the priority information may be set in the clear processing unit  56  not via the UI  565  but from a server device  3061 , for example. Information indicating the results of determination made by the determining unit  567  is stored in a post-processing control storage unit  568 . 
     An exemplary operation of the clear processing unit  56  will now be described with an emphasis on operations of the clear-toner plane processing unit  563  and the determining unit  567 .  FIG. 14  is a flowchart of an exemplary operation of the clear-toner plane processing unit  563 . As illustrated in  FIG. 14 , the clear-toner plane processing unit  563  acquires image data to be transferred onto a recording medium via the data acquiring unit  58  at Step S 100 . 
     The clear-toner plane processing unit  563  then determines whether the image data acquired at Step S 100  includes a gloss-control plane (gloss-control plane image data) at Step S 102 . If the clear-toner plane processing unit  563  determines that the image data includes a gloss-control plane (Yes at Step S 102 ), the system control goes to Step S 104 . By contrast, if the clear-toner plane processing unit  563  determines that the image data includes no gloss-control plane (No at Step S 102 ), the system control goes to Step S 112 . 
     The clear-toner plane processing unit  563  determines whether the image data acquired at Step S 100  includes a clear plane at Step S 104 . If the clear-toner plane processing unit  563  determines that the image data includes a clear plane (Yes at Step S 104 ), the system control goes to Step S 106 . By contrast, if the clear-toner plane processing unit  563  determines that the image data includes no clear plane (No at Step S 104 ), the system control goes to Step S 110 . 
     The clear-toner plane processing unit  563  determines whether the gloss-control plane or the clear plane is to be prioritized based on the priority information at Step S 106 . If the clear-toner plane processing unit  563  determines to prioritize the clear plane, the system control goes to Step S 108 . By contrast, if the clear-toner plane processing unit  563  determines to prioritize the gloss-control plane, the system control goes to Step S 110 . 
     The clear-toner plane processing unit  563  determines whether the density of the clear plane is 0% at Step S 108 . If the clear-toner plane processing unit  563  determines that the density of the clear plane is 0% (Yes at Step S 108 ), the system control goes to Step S 110 . By contrast, if the clear-toner plane processing unit  563  determines that the density of the clear plane is not 0% (No at Step S 108 ), the system control goes to Step S 118 . 
     The clear-toner plane processing unit  563  adds a surface effect of the gloss-control plane to a list at Step S 110 .  FIG. 15  illustrates an example of a list (results of acquisition of surface effect information) to which the clear-toner plane processing unit  563  adds a surface effect of the gloss-control plane. The list illustrated in  FIG. 15  indicates whether the surface effects are present in a single page. The surface effect information acquired by the clear-toner plane processing unit  563  may be formed in another format as long as the surface effect information can determine whether each of the surface effects is present. The list to which the clear-toner plane processing unit  563  adds a surface effect may list the surface effects that are present or may be a list in which the number of dots counted for each surface effect is associated with each surface effect. 
     The clear-toner plane processing unit  563  determines whether the image data acquired at Step S 100  includes a clear plane at Step S 112 . If the clear-toner plane processing unit  563  determines that the image data includes a clear plane (Yes at Step S 112 ), the system control goes to Step S 114 . By contrast, if the clear-toner plane processing unit  563  determines that the image data includes no clear plane (No at Step S 112 ), the processing is terminated. 
     The clear-toner plane processing unit  563  determines whether it is necessary to perform gloss-control using the clear plane based on settings made by the user at Step S 114 . If the clear-toner plane processing unit  563  determines that it is necessary to perform gloss-control (Yes at Step S 114 ), the system control goes to Step S 116 . By contrast, if the clear-toner plane processing unit  563  determines that it is not necessary to perform gloss-control (No at Step S 114 ), the system control goes to Step S 118 . 
     The clear-toner plane processing unit  563  adds a surface effect to be applied using the clear plane to the list illustrated in  FIG. 15  at Step S 116 . 
     The clear-toner plane processing unit  563  then refers to the list illustrated in  FIG. 15  and performs clear-toner plane processing for generating a clear-toner plane of each pixel that produces surface effects properly at Step S 118 . 
       FIG. 16  is a flowchart of an exemplary operation of the determining unit  567 . As illustrated in  FIG. 16 , the determining unit  567  determines a selection method of post-processing control included in the priority information at Step S 200 . If the determining unit  567  determines that the selection method is “prioritize ON”, the system control goes to Step S 202 . If the determining unit  567  determines that the selection method is “prioritize OFF”, the system control goes to Step S 208 . If the determining unit  567  determines that the selection method is “fixed to OFF”, the system control goes to Step S 204 . 
     The determining unit  567  determines whether there is a surface effect for which the glosser  80  is to be turned ON in a single page (refer to  FIG. 12 ) at Step S 202 . If the determining unit  567  determines that there is a surface effect for which the glosser  80  is to be turned ON (Yes at Step S 202 ), the system control goes to Step S 206 . By contrast, if the determining unit  567  determines that there is no surface effect for which the glosser  80  is to be turned ON (No at Step S 202 ), the system control goes to Step S 204 . 
     The determining unit  567  determines to turn OFF the glosser  80  at Step S 204 . In other words, the determining unit  567  determines to preferentially perform post-processing for which the glosser  80  is turned OFF in page units (glosser control is OFF). 
     The determining unit  567  determines to turn ON the glosser  80  at Step S 206 . In other words, the determining unit  567  determines to preferentially perform post-processing for which the glosser  80  is turned ON in page units (the glosser control is ON). 
     The determining unit  567  determines whether there is a surface effect for which the glosser  80  is to be turned OFF in the single page (refer to  FIG. 12 ) at Step S 208 . If the determining unit  567  determines that there is a surface effect for which the glosser  80  is to be turned OFF (Yes at Step S 208 ), the system control goes to Step S 210 . By contrast, if the determining unit  567  determines that there is no surface effect for which the glosser  80  is to be turned OFF (No at Step S 208 ), the system control goes to Step S 212 . 
     The determining unit  567  determines to turn OFF the glosser  80  at Step S 210 . In other words, the determining unit  567  determines to preferentially perform post-processing for which the glosser  80  is turned OFF in page units (the glosser control is OFF). 
     The determining unit  567  determines whether there is a surface effect for which the glosser  80  is to be turned ON in the single page at Step S 212 . If the determining unit  567  determines that there is a surface effect for which the glosser  80  is to be turned ON (Yes at Step S 212 ), the system control goes to Step S 214 . By contrast, if the determining unit  567  determines that there is no surface effect for which the glosser  80  is to be turned ON (No at Step S 212 ), the system control goes to Step S 210 . 
     The determining unit  567  determines to turn ON the glosser  80  at Step S 214 . In other words, the determining unit  567  determines to preferentially perform post-processing for which the glosser  80  is turned ON in page units (the glosser control is ON). 
     The si3 unit  57  ( FIG. 11 ) integrates the pieces of 2-bit image data of CMYK on which the halftone processing is performed and the 2-bit image data of the clear-toner plane generated by the clear processing unit  56  and outputs the image data thus integrated to the MIC  60 . If the clear processing unit  56  generates no image data of the clear-toner plane to be used in the printer  70 , the si3 unit  57  outputs image data obtained by integrating the pieces of 2-bit image data of CMYK. As a result, the DFE  50  outputs four or five pieces of 2-bit image data to the MIC  60 . The si3 unit  57  also outputs the ON-OFF information of the glosser  80  received from the clear processing unit  56  to the MIC  60 . 
     The MIC  60  ( FIG. 1 ) is connected to the DFE  50  and the printer  70 . The MIC  60  outputs device configuration information indicating the configuration of the device provided as the post-processing device to the DFF  50 . The MIC  60  receives pieces of image data of the color planes and pieces of image data of the clear-toner planes from the DFE  50 . The MIC  60  then sorts the pieces of image data into devices corresponding thereto and controls the post-processing device. More specifically, as illustrated in  FIG. 17 , the MIC  60  outputs the pieces of image data of the CMYK color planes among the pieces of image data output from the DFE  50  to the printer  70 . If there is image data of the clear-toner plane to be used in the printer  70 , the MIC  60  also outputs the image data of the clear-toner plane to the printer  70 . In addition, the MIC  60  uses the ON-OFF information received from the DFE  50  to turn ON or OFF the glosser  80 . The glosser  80  may be switched between a path for performing fixing and a path for performing no fixing based on the ON-OFF information. 
     As illustrated in  FIG. 17 , a printing system formed of the printer  70  and the glosser  80  includes a conveying path for conveying a recording medium. Specifically, the printer  70  includes a plurality of electrophotography photosensitive drums, a transfer belt onto which a toner image formed on the photosensitive drums is transferred, a transfer device that transfers a toner image on the transfer belt onto a recording medium, and a fixing unit that fixes a toner image on a recording medium to the recording medium. The recording medium is conveyed by a conveying member, which is not illustrated, to the printer  70  and the glosser  80  in this order through the conveying path. After these devices sequentially perform processing on the recording medium to form an image and apply a surface effect thereto, the recording medium is conveyed by a conveying mechanism, which is not illustrated, through the conveying path and is ejected outside of the printing system. 
       FIG. 18  is a schematic of results of printing performed by the printing control system according to the present embodiment when gloss-control plane data indicates a plurality of types of post-processing incapable of being performed simultaneously by the glosser  80  in page units. As illustrated in  FIG. 18 , if the DFE  50  receives image data including gloss-control plane data P 1  indicating post-processing of premium gloss, tactile pattern, and matte, the printing control system outputs a print result P 1   a  and a print result P 1   b , for example. In other words, if the selection method of the post-processing control is “prioritize ON”, the printing control system performs post-processing for which the glosser  80  is turned ON in accordance with the surface effect selection table illustrated in  FIG. 12  to output the print result P 1   a . In the print result P 1   a , the post-processing corresponding to tactile pattern and matte in the gloss-control plane data P 1  is replaced by post-processing corresponding to premium gloss. By contrast, if the selection method of the post-processing control is “prioritize OFF” or “fixed to OFF”, the printing control system performs post-processing for which the glosser  80  is turned OFF to output the print result P 1   b . In the print result P 1   b , the post-processing corresponding to tactile pattern and matte in the gloss-control plane data P 1  is performed without any change, whereas the post-processing corresponding to premium gloss in the gloss-control plane data P 1  is replaced by post-processing corresponding to gloss. 
     A change in the surface effect selection table will now be described. The surface effect selection table illustrated in  FIG. 12  is determined in advance and stores therein an operation (ON or OFF) of the glosser  80  in a manner associated with each of the surface effects. The surface effect selection table may be changed via the UI  565 , for example.  FIG. 19  is a schematic of a menu screen used for changing the surface effect selection table displayed by the UI  565 , for example. As illustrated in  FIG. 19 , turning ON or OFF of the glosser (the rightmost column in  FIG. 12 ) in the surface effect selection table may be changed via the menu screen. The surface effect selection table may be changed for each surface effect or each group, such as premium gloss and gloss. As described above, the printing system uses the surface effect selection table capable of being changed and specifies the selection method of the post-processing control, thereby making it possible to change the surface effects. 
     Second Embodiment 
     In the first embodiment, the host device  10  includes the plane data generating unit  122  and the print data generating unit  123 , and the DFE  50  includes the clear processing unit  56 . The host device  10  performs plane data generation processing for generating color plane data, clear plane data, and gloss-control plane data and generation processing of print data. The DFE  50  performs generation processing of clear-toner plane data. The configuration of the printing system, however, is not limited thereto. 
     In other words, any one of a plurality of types of processing performed by a single device may be performed by one or more other devices connected to the single device via a network. 
     In a printing control system (an image forming system) according to a second embodiment of the present invention, for example, a part of functions of a host device and a DFE is provided to a server device on a network. 
       FIG. 20  is an exemplary block diagram of a configuration of the printing control system according to the second embodiment. As illustrated in  FIG. 20 , the printing control system includes a host device  3010 , a DFE  3050 , an MIC  60 , a printer  70 , a glosser  80 , and a server device  3060  on a cloud. The post-processing device, such as the glosser  80 , is not limited thereto. 
     In the present embodiment, the host device  3010  and the DFE  3050  are connected to the server device  3060  via a network, such as the Internet. Furthermore, in the present embodiment, the plane data generating unit and the print data generating unit of the host device  10  in the first embodiment and the clear processing unit of the DFE  50  in the first embodiment are provided to the server device  3060 . 
     The connection configuration of the host device  3010 , the DFE  3050 , the MIC  60 , the printer  70 , and the glosser  80  is the same as that in the first embodiment. 
     Specifically, in the second embodiment, the host device  3010  and the DFE  3050  are connected to the single server device  3060  via a network (cloud), such as the Internet, for example. The server device  3060  performs the plane data generation processing for generating color plane data, clear plane data, and gloss-control plane data, the generation processing of print data, and the generation processing of clear-toner plane data. 
     An explanation will be made of the generation processing of a clear-toner plane required for printing performed by the printing control system according to the second embodiment. The whole process of the generation processing of a clear toner plane will now be described.  FIG. 21  is a sequence diagram of the whole process of the generation processing of a clear toner plane according to the second embodiment. 
     The host device  3010  receives image specification information and specification information from the user (Step S 3201 ). The host device  3010  then transmits a print data generating request together with the image specification information and the specification information to the server device  3060  (Step S 3202 ). 
     The server device  3060  receives the print data generating request together with the image specification information and the specification information and generates image data of the color plane, image data of the gloss-control plane, and image data of the clear plane (Step S 3203 ). The server device  3060  then generates print data from the pieces of image data (Step S 3204 ) and transmits the print data thus generated to the host device  3010  (Step S 3205 ). 
     If the host device  3010  receives the print data, the host device  3010  transmits the print data to the DFE  3050  (Step S 3206 ). 
     If the DFE  3050  receives the print data from the host device  3010 , the DFE  3050  analyzes the print data to obtain image data of the color plane, image data of the gloss-control plane, and image data of the clear plane. The DFE  3050  then performs conversion, correction, and other processing on the pieces of image data (Step S 3207 ). The DFE  3050  then transmits the image data of the color plane, the image data of the gloss-control plane, the image data of the clear plane, and a clear-toner plane generating request to the server device  3060  (Step S 3208 ). 
     If the server device  3060  receives the image data of the color plane, the image data of the gloss-control plane, the image data of the clear plane, and the clear-toner plane generating request, the server device  3060  determines ON-OFF information (Step S 3209 ) and generates image data of a clear toner plane (Step S 3210 ). The server device  3060  then transmits the ON-OFF information and the image data of the clear toner plane thus generated to the DFE  3050  (Step S 3211 ). 
     As described above, the server device  3060  on the cloud generates image data of the color plane, image data of the gloss-control plane, image data of the clear plane, print data, and image data of the clear toner plane in the second embodiment. As a result, even if there are a plurality of host devices  3010  and DFEs  3050 , it is possible to collectively change the density value selection table and the surface effect selection table, for example, besides to enjoy the advantageous effects of the first embodiment. This is convenient for an administrator. 
     While the single server device  3060  on the cloud performs plane data generation processing for generating color plane data, clear plane data, and gloss-control plane data, generation processing of print data, and generation processing of clear toner plane data in the second embodiment, the configuration is not limited thereto. 
     Two or more server devices may be provided on the cloud, and the processing described above may be distributed to and performed by the two or more server devices, for example. 
     The hardware configuration of the host devices  10  and  3010 , the DFEs  50  and  3050 , and the server devices  3060  and  3061  will now be described.  FIG. 22  is a block diagram of the hardware configuration of the host devices  10  and  3010 , the DFEs  50  and  3050 , and the server devices  3060  and  3061 . The host devices  10  and  3010 , the DFEs  50  and  3050 , and the server devices  3060  and  3061  have a hardware configuration using a typical computer. The hardware configuration mainly includes a control device  2901  such as a CPU, a main memory  2902  such as a ROM and a RAM, an auxiliary memory  2903  such as an HDD, an input device  2905  such as a keyboard and a mouse, and a display device  2904  such as a display. The control device  2901  collectively controls each device. The main memory  2902  stores therein various types of data and computer programs. The auxiliary memory  2903  stores therein various types of data and computer programs. 
     An image processing program (including an image processing application; the same shall apply hereinafter) executed in the host devices  10  and  3010  is provided as a computer program product in a manner recorded in a computer-readable storage medium, such as a compact disk read-only memory (CD-ROM), a flexible disk (FD), a compact disk recordable (CD-R), and a digital versatile disk (DVD), as a file in an installable or executable format. 
     The image processing program executed in the host devices  10  and  3010  may be provided in a manner stored in a computer connected to a network such as the Internet to be made available for downloads via the network. Furthermore, the image processing program executed in the host devices  10  and  3010  according to the embodiments may be provided or distributed over a network such as the Internet. 
     The image processing program executed in the host devices  10  and  3010  may be provided in a manner incorporated in advance in a ROM or the like. 
     The image processing program executed in the host devices  10  and  3010  has a module configuration including each unit described above (the image processing unit, the plane data generating unit, the print data generating unit, the input control unit, and the display control unit). In actual hardware, the CPU (processor) reads and executes the image processing program from the storage medium described above to load each unit on the main memory. Thus, the image processing unit, the plane data generating unit, the print data generating unit, the input control unit, and the display control unit are generated on the main memory. 
     The printing control processing performed by the DFEs  50  and  3050  may be executed by a printing control program serving as software besides by hardware. In this case, the printing control program executed in the DFEs  50  and  3050  according to the embodiments is provided in a manner incorporated in advance in a ROM or the like. 
     The printing control program executed in the DFEs  50  and  3050  may be provided as a computer program product in a manner recorded in a computer-readable storage medium, such as a CD-ROM, an FD, a CD-R, and a DVD, as a file in an installable or executable format. 
     The printing control program executed in the DFEs  50  and  3050  may be provided in a manner stored in a computer connected to a network such as the Internet to be made available for downloads via the network. Furthermore, the printing control program executed in the DFE  50  according to the embodiments may be provided or distributed over a network such as the Internet. 
     The printing control program executed in the DFEs  50  and  3050  has a module configuration including each unit described above (the rendering engine, the halftone engine, the TRC, the si1 unit, the si2 unit, the si3 unit, and the clear processing unit). In actual hardware, the CPU (processor) reads and executes the printing control program from the ROM to load each unit on the main memory. Thus, the rendering engine, the halftone engine, the TRC, the si1 unit, the si2 unit, the si3 unit, and the clear processing unit are generated on the main memory. 
     The generation processing of each data performed by the server devices  3060  and  3061  may be executed by a generation program serving as software besides by hardware. In this case, the generation program executed in the server devices  3060  and  3061  according to the embodiments is provided in a manner incorporated in advance in a ROM or the like. 
     The generation processing program of each data executed in the server devices  3060  and  3061  may be provided as a computer program product in a manner recorded in a computer-readable storage medium, such as a CD-ROM, an FD, a CD-R, and a DVD, as a file in an installable or executable format. 
     The generation processing program of each data executed in the server devices  3060  and  3061  may be provided in a manner stored in a computer connected to a network such as the Internet to be made available for downloads via the network. Furthermore, the generation processing program of each data executed in the server devices  3060  and  3061  according to the embodiments may be provided or distributed over a network such as the Internet. 
     The generation processing program of each data executed in the server devices  3060  and  3061  has a module configuration including each unit described above (the plane data generating unit, the print data generating unit, and the clear processing unit). In actual hardware, the CPU (processor) reads and executes the generation program from the ROM to load each unit on the main memory. Thus, the plane data generating unit, the print data generating unit, and the clear processing unit are generated on the main memory. 
     While the image forming systems according to the embodiments include the host devices  10  and  3010 , the DFEs  50  and  3050 , the MIC  60 , the printer  70 , and the glosser  80 , the configuration is not limited thereto. The DFEs  50  and  3050 , the MIC  60 , and the printer  70  may be integrated as one image forming apparatus, for example. Furthermore, these devices may be formed as an image forming apparatus further including the glosser  80 . 
     While the image forming systems according to the embodiments form an image with a plurality of color toners of CMYK, the image forming systems may form an image with one color toner. 
     While the printer systems according to the embodiments include the MIC  60 , the configuration is not limited thereto. The configuration may not include the MIC  60  by shifting the processing performed by the MIC  60  and the function of the MIC  60  to other devices, such as the DFE  50 . 
     According to the embodiments, it is possible to accept a print request including a plurality of surface effects to be produced by a plurality of types of post-processing incapable of being performed simultaneously by a post-processing device in a single page and control the post-processing device so as to produce the surface effects properly. 
     Although the invention has been described with respect to specific embodiments for a complete and clear disclosure, the appended claims are not to be thus limited but are to be construed as embodying all modifications and alternative constructions that may occur to one skilled in the art that fairly fall within the basic teaching herein set forth.