Patent Publication Number: US-9840092-B2

Title: Image forming apparatus using a pre-processing liquid and a post-processing liquid, and an image forming method using a pre-processing liquid and a post-processing liquid

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation application of, and claims the benefit of priority under 35 U.S.C. §120 from, U.S. application Ser. No. 13/875,070, filed May 1, 2013, which claims priority to Japanese Patent Application 2013-092704, filed on Apr. 25, 2013, which claims priority to Japanese Patent Application 2012-104793, filed on May 1, 2012. The entire contents of each of the above applications are incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     Embodiments of the present invention relate to an image forming apparatus and an image forming method. 
     2. Description of the Related Art 
     The inkjet image forming method has rapidly been adopted in recent years due to the method&#39;s advantageous property of being an easy enhancement for a method of forming color images, as well as the fact that the method is noiseless and has a low running cost. 
     JP-A No. H10-226055 discloses a preliminary process of ejecting ink after ejecting a processing liquid onto a printing medium and a post-process of ejecting the processing liquid after ejecting the ink on the printing medium. 
     With the technology disclosed in the above-described document, however, the processing liquid makes a coloring agent in the ink insoluble or coagulated. As a result, when the printing medium on which an image is formed by the ink is scraped against an object (e.g., the other printing medium), a part of the image is occasionally peeled off. 
     SUMMARY OF THE INVENTION 
     The embodiments of the present invention have been developed in view of the above-described problems of the conventional techniques. 
     An objective of the embodiments of the present invention is to provide an image forming apparatus and an image formation method that can improve the abrasion resistance of the printing medium on which the image is formed. 
     In one aspect, there is provided an image forming apparatus including an image forming unit configured to eject droplets from an image forming apparatus, and to form an image on a surface of the printing medium, a pre-processing unit configured to apply a pre-processing liquid to the surface of the printing medium before the image is formed by the image forming unit, and a post-processing unit configured to apply a post-processing liquid different from the pre-processing liquid to the surface of the printing medium after the image is formed by the image forming unit. The pre-processing unit applies an amount of the pre-processing liquid which is determined based on the type of the printing medium and the post-processing unit applies an amount of the post-processing liquid which is determined based on the type of the printing medium. 
     In another aspect, there is provided an image forming method including the steps of applying the pre-processing liquid to a surface of the printing medium, forming an image on the surface of the printing medium on which pre-processing liquid was applied, and applying the post-processing liquid different from the pre-processing liquid to the surface of the printing medium on which the image is formed, wherein the pre-processing liquid is applied in an amount which is determined based on the type of the printing medium and the post-processing liquid is applied in an amount which is determined based on the type of the printing medium. 
     According to the embodiments of the present invention, there is provided the image forming apparatus and the image formation method that can improve the abrasion resistance of the printing medium on which the image is formed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic side view showing an example of the image forming apparatus according to one embodiment of the present invention; 
         FIG. 2  is a schematic configuration view showing an example of a pre-processing unit of the image forming apparatus according to one embodiment of the present invention; 
         FIG. 3  is a schematic configuration view showing an example of a drying unit of the image forming apparatus according to one embodiment of the present invention; 
         FIG. 4  is a schematic plan view showing an example of an image forming unit and a post-processing unit of the image forming apparatus according to one embodiment of the present invention; 
         FIG. 5  is a schematic plan view showing an example of a head unit of an ejecting head for ejecting the black color ink of the image forming unit according to one embodiment of the present invention; 
         FIG. 6  is a cross sectional view showing an example of a cross section shown along a longitudinal direction of a liquid chamber; 
         FIG. 7  is a cross sectional view showing an example of a cross section shown along a lateral direction of the liquid chamber; 
         FIG. 8  is an illustration showing an example of the printing medium on which the image is formed by the image forming apparatus according to one embodiment of the present invention; 
         FIG. 9  is a schematic configuration view showing an example of a controlling unit of an image forming apparatus and a superordinate device of the controlling unit according to one embodiment of the present invention; 
         FIG. 10  is a schematic configuration view showing of an example of the superordinate device of the controlling unit according to one embodiment of the present invention; 
         FIG. 11  is a functional block diagram showing of an example of functions of the controlling unit according to one embodiment of the present invention; 
         FIG. 12  is a functional block diagram showing of an example of functions of a data management unit in the controlling unit according to one embodiment of the present invention; 
         FIG. 13  is a functional block diagram showing of an example of functions of an image output unit in the controlling unit according to one embodiment of the present invention; 
         FIG. 14  is a flowchart showing of an exemplary operation by the image forming apparatus according to a first exemplary embodiment of the present invention; 
         FIG. 15  is an illustration showing of the relationship between a granularity of an image and a coating amount of pre-processing liquid according to the first exemplary embodiment of the present invention; 
         FIG. 16  is a flowchart showing an exemplary operation by the image forming apparatus according to a second exemplary embodiment of the present invention; 
         FIG. 17  is a flowchart showing an exemplary operation by the image forming apparatus according to a third exemplary embodiment of the present invention; 
         FIG. 18  is a flowchart showing an exemplary operation by the image forming apparatus according to a fourth exemplary embodiment of the present invention; 
         FIG. 19  is a flowchart showing an exemplary operation by the image forming apparatus according to a fifth exemplary embodiment of the present invention; and 
         FIG. 20  is a flowchart showing an exemplary operation by the image forming apparatus according to a sixth exemplary embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Hereinafter, embodiments of the present invention will be explained with reference to an inkjet image forming apparatus. This invention can be also applied to any image forming apparatus having an ejecting unit (ejecting head, ink head, recording head, or the like) that forms (prints or the like) an image on a printing medium by ejecting recording liquid droplets (ink or the like) such as a facsimile device, a copier device, a multi-function peripheral, the like, or any device not specifically described herein. Embodiments of the present invention will be explained in the following order. 
     1. Configuration of an image forming apparatus 
     2. Configuration of a sheet feeding unit 
     3. Configuration of a pre-processing unit 
     4. Configuration of a drying unit 
     5. Configuration of an image forming unit 
     6. Configuration of a post-processing unit 
     7. Configuration of a sheet discharging unit 
     8. Configuration of a controlling unit 
     9. A first exemplary embodiment (an example in which the amount of post-processing liquid is determined based on type of the printing medium) 
     10. A second exemplary embodiment (an example in which the amount of post-processing liquid is determined based on amount of pre-processing amount) 
     11. A third exemplary embodiment (an example in which an amount of post-processing liquid is adjusted based on type of the printing medium) 
     12. A fourth exemplary embodiment (an example of adding a determination of drying strength to the first example) 
     13. A fifth exemplary embodiment (an example of adding a determination of drying strength to the second example) 
     14. A sixth exemplary embodiment (an example of adding a determination of drying strength to the third example) 
     The configuration of an image forming apparatus 
     The structure of an image forming apparatus  100  according to an embodiment of the present invention is explained with reference to  FIGS. 1 to 5 . 
     Although the present invention has been described using an image forming apparatus having ejecting heads (recording head, print heads, ink heads) corresponding to the four colors black (K), cyan (C), magenta (M), and yellow (Y), the scope of the present invention is not limited to an image forming apparatus having such ejecting heads. The scope of the present invention also includes an image forming apparatus having ejecting heads corresponding to green (G) red (R), light cyan (LC), and/or other color(s), or an image forming apparatus having only an ejecting head corresponding to black (K). In the following explanation, Y, C, M, and K represent the colors of yellow, cyan, magenta, and black. 
     Although the present invention has been described with reference to a continuous sheet in the form of a roll (hereinafter referred to as “sheet roll Md”) as the printing medium, the printing medium used by the printing apparatus of the present invention is not limited to the sheet roll. The printing medium used by the printing apparatus of the present invention may also be a cut sheet. The scope of the printing medium used by the printing apparatus of the present invention includes any medium on which an image can be formed by liquid droplets on the surface of the medium such as standard paper, high quality paper, thick paper, thin paper, cut sheet, sheet roll, an OHP sheet, synthetic resin film, and metal thin film. The continuous sheet form includes perforated box paper or unperforated roll paper. A page of the box paper 
     , for example, corresponds to an area between one perforation and next perforation. 
     As shown in  FIG. 1 , the image forming apparatus  100  according to an embodiment includes a sheet feeding unit  10  that feeds the sheet roll Md (printing medium), a pre-processing unit  20  that applies a pre-processing to the sheet roll Md, which is fed by the sheet feeding unit  10 , and a drying unit  30  that dries the sheet roll Md, which is treated by the pre-process unit  20 . Furthermore, the image forming apparatus  100  includes an image forming unit  40  that forms an image on a surface of the sheet roll Md, a post-processing unit  50  that applies a post-processing to the sheet roll Md, on which an image is formed by the image forming unit  40 , and a sheet discharging unit  60  that discharges the sheet roll Md, which is treated by the post-processing unit  50 . 
     The sheet feeding unit  10  of the image forming apparatus  100  according to an embodiment feeds the sheet roll Md, the pre-processing unit  20  applies pre-processing to the surface of the sheet roll Md, and the drying unit  30  dries the surface of the sheet roll Md. The image forming unit  40  of the image forming apparatus  100  forms an image on the surface of the sheet roll Md, which has been treated by the pre-processing and has been dried. Furthermore, the post-processing unit  50  of the image forming apparatus  100  applies the post-processing to the sheet roll Md on which is formed an image. Then, the sheet discharging unit  60  of the image forming apparatus  100  rolls up (discharges) the sheet roll Md. 
     Hereinafter, each component of the image forming apparatus  100  according to the present invention will be concretely described. The image forming apparatus  100  controls the pre-processing unit  20 , the drying unit  30  (a pre-processing liquid drying unit  31 , or a post-processing liquid drying unit  32 ) or post-processing unit  50  based on type of printing medium. The image forming apparatus  100  is able to exclude the drying unit  30  or the like. 
     The Configuration of the Sheet Feeding Unit 
     The sheet feeding unit  10  feeds a printing medium to the pre-processing unit  20 . In this embodiment, the sheet feeding unit  10  includes a sheet holder  11 , and a plurality of conveyance rollers  12 . The conveyance rollers  12  of the sheet feeding unit  10  convey a sheet roll Md which is held by the sheet holder  11  to the pre-processing unit. 
     The Configuration of the Pre-Processing Unit 
     The pre-processing unit  20  treats a printing medium before an image is formed by the image processing unit  40  on the printing medium. In this embodiment, the pre-processing unit  20  treats a surface of the sheet roll Md which is conveyed by the feeding unit  10 . The pre-processing unit  20  treats the surface with a pre-processing liquid. 
     A pre-processing is a process of uniformly applying the pre-processing liquid to a surface of the sheet roll Md (printing medium). The pre-processing liquid has a function of aggregating ink droplets. 
     The pre-processing process enables the image forming apparatus  100  to apply a pre-processing liquid, which has the function of aggregating ink droplets on a surface of the printing medium before the image processing unit  40  forms an image on the printing medium, when an image is formed by the image forming apparatus  100  on a different printing medium from a sheet intended for inkjet formation. The pre-processing process enables the image forming apparatus  100  to reduce and address problems such as bleeding of the image, problems related to image density, problems related to image tone, ink strike-through, problems related to water resistance, and problems related to environment resistance. That is, the image forming apparatus  100  is able to improve the quality of an image which is formed on the printing medium as a result of the application of the pre-processing liquid, which has a function of aggregating ink droplets on the printing medium, by the pre-processing unit  20  before the image forming unit  40  forms the image on the printing medium. 
     Additionally, the image forming apparatus  100  may apply the pre-processing liquid, which has the function of aggregating ink droplets on the sheet designated for inkjet, by the pre-processing unit  20 , before the image forming unit  40  forms the image on the sheet designated for inkjet. 
     The pre-processing method performed by the pre-processing unit  20  according to an embodiment is not restricted and can be implemented appropriately according to the object. Examples of the method for applying include a blade coating method, a gravure coating method, a gravure offset coating method, a bar coating method, a roll coating method, a knife coating method, an air knife coating method, a comma coating method, a U-comma coating method, an AKKU coating method, a smoothing coating method, a micro gravure coating method, a reverse roll coating method, a 4-roll or 5-roll coating method, a dip coating method, a curtain coating method, a slide coating method and a die coating method. 
     The pre-processing unit  20  according to an embodiment is able to use a treating liquid, which includes water soluble aliphatic amino acids as the pre-processing liquid. The treating liquid, which includes water soluble aliphatic amino acids, has the behavior of aggregating water-dispersible colorant. The aggregating converges each of the water-dispersible colorant particles. 
     Furthermore, the pre-processing unit  20  is able to adsorb ions onto the surface of the water-dispersible colorant by adding an ionic object such as water soluble aliphatic amino acids into the pre-processing liquid. This enables the pre-processing unit  20  to neutralize the surface charge of the water-dispersible colorant. This also enables the pre-processing unit  20  to aggregate more of the water-dispersible colorant by increasing the aggregation resulting from the force between the molecules. 
     An embodiment of a pre-processing unit  20  using a roll coating method will be described with reference to  FIG. 2 . 
     As shown in  FIG. 2 , the pre-processing unit  20  applies a pre-processing liquid  20 L, which is stored in the pre-processing unit  20 , to a surface of the sheet roll Md, which is conveyed (fed) to the pre-processing unit  20  by the feeding unit  10  ( FIG. 1 ). 
     Specifically, a stirring roller  21  and a transferring roller  22  first form the pre-processing liquid  20 L as a thin film on a surface of an applying roller  23 . Next, the pre-processing unit  20  presses the applying roller  23  onto a platen roller  24  and rotates the applying roller  23 . In this state, the pre-processing unit  20  conveys the sheet roll Md to a place between the applying roller  23  and the platen roller  24 . This enables the pre-processing liquid  20 L to be applied to a surface of the sheet roll Md. 
     A pressure controller  25  of the pre-processing unit  20  controls the nip pressure between the applying roller  23  and the platen roller  24  when the pre-processing unit applies the pre-processing liquid  20 L. The nip pressure is a force acting on a contact position between the applying roller  23  and the platen roller  24 . The pre-processing unit  20  is able to control (change) the application amount of the pre-processing liquid to the sheet roll Md by controlling (changing) the nip pressure by the pressure controller  25 . The application amount of the pre-processing liquid relates to the amount of liquid, the amount of applying, the amount of liquid after drying, and the thickness of the liquid film. 
     Furthermore, the pre-processing unit  20  controls the rotation speed of the applying roller  23  and the platen roller  24 . The pre-processing unit is able to control (change) the application amount of the pre-processing liquid by controlling (changing) the rotation speed of the applying roller  23  and the platen roller  24 . Additionally, the pre-processing unit  20  may control the applying unit  23  and/or the platen roller  24  by controlling the power source (motor or the like) to drive the applying unit  23  and/or the platen roller  24 . 
     Accordingly, the pre-processing unit  20  of the image forming apparatus according to an embodiment of present invention, implementing the roll coating method, is able to more uniformly apply a liquid to a surface of the sheet roll Md (printing medium) as compared with using the spray coating method. The pre-processing unit  20  of this embodiment is able to uniformly and thinly apply the pre-processing liquid  20 L to a surface of the sheet roll Md even when the pre-processing liquid  20 L has a high viscosity. The pre-processing unit  20  enables the image, which is formed after the implementation of the pre-processing method, to reduce the image bleeding by uniformly and thinly applying the pre-processing liquid  20 L to the sheet roll Md. The pre-processing unit  20  also enables improvement in the image quality. 
     The pre-processing unit  20  of the image forming apparatus according to this embodiment is able to apply the amount of the pre-processing liquid  20 L, suitable for the image forming method and post-processing method, to the sheet roll Md (printing medium) by controlling the amount of the pre-processing liquid using the applying roller  23  and/or the platen roller  24 . 
     Furthermore, the pre-processing unit  20  of the image forming apparatus according to this embodiment is able to control the application amount of the pre-processing liquid  20 L based on the type of the printing medium by controlling the amount of the pre-processing liquid using the applying roller  23  and/or the platen roller  24 . The pre-processing unit  20  of the image forming apparatus  100  according to this embodiment is able to improve the image quality because the pre-processing unit  20  is able to control the application amount of the pre-processing liquid  20 L. 
     Configuration of the Drying Unit 
     The drying unit  30  implements drying of the printing medium by heating or the like. As shown in  FIG. 1 , the drying unit  30  in this embodiment includes the pre-processing liquid drying unit  31 , which dries the sheet roll Md which was treated by the pre-processing unit  20 , and the post-processing liquid drying unit  32 , which dries the sheet roll Md which was treated by the post-processing unit  50 . The drying unit  30  of the image forming apparatus  100  according to this embodiment includes rollers  31   h / 32   h  and controls the drying strength of the pre-processing liquid drying unit  31  and/or the drying strength of the post-processing liquid drying unit  32  based on the type of printing medium. A configuration of the pre-processing liquid drying unit  31  will be described with reference to  FIG. 3 . 
     As shown in  FIG. 3 , the pre-processing liquid drying unit  31  of this embodiment uses a plurality of heating rollers  311  to  316  to increase the drying effect. The pre-processing liquid drying unit  31  controls (changes) the drying strength based on the type of printing medium. Furthermore, the pre-processing liquid drying unit  31  also can control the drying strength based on the application amount of the pre-processing liquid  20 L per unit area. 
     Specifically, the heating roller  311  (or  312  or the like) is heated from 40 degrees C. to 80 degrees C., and a surface of the sheet roll Md, on which was applied the pre-processing liquid  20 L, contacts to the heating roller  311  (or  312 , or the like). This enables the pre-processing liquid drying unit  31  to dry the sheet roll Md (by drying the pre-processing liquid on the sheet roll Md) thereby evaporating the water in the pre-processing liquid due to the heating of the surface of the sheet roll Md by the heating roller  311  (or  312 , or the like) 
     The pre-processing liquid drying unit  31  lowers the temperature of the heating roller  311  ( 312 , etc) when the pre-processing liquid drying unit  31  lowers the drying strength. For example, the pre-processing liquid drying unit  31  lowers the temperature when ink is used which has low penetrability, and raises the temperature when ink is used which has high penetrability. The pre-processing liquid drying unit heats the heating unit  311  (or  312  or the like) from 40 degrees C. to 80 degrees C., for example. 
     Furthermore, the pre-processing liquid drying unit  31  may control the drying strength by controlling the number of heating rollers which are used. In such a manner heating roller  311  and heating roller  312  may be heated and the other heating rollers are not heated. Additionally, the pre-processing liquid drying unit  31  is able to control the drying strength by controlling both the temperature of the heating roller and the number of rollers which are used. In addition, the pre-processing liquid drying unit  31  is able to implement control by only controlling the temperature of the heating roller or the number of heating rollers which are used. 
     A description of the configuration of the post-processing liquid drying unit  32  will be omitted due to the similarities to the pre-processing liquid drying unit  31 . Additionally, the post-processing liquid drying unit  32  is able to control the drying strength based on the type of printing medium. Furthermore, the post-processing liquid drying unit  32  also is able to control the drying strength based on the amount of the post-processing liquid  50 L applied by the post processing unit  50  per unit area. Accordingly, the drying unit  30  (the pre-processing liquid drying unit  31  and the post-processing liquid drying unit  32 ) are able to control the drying strength by controlling the temperature of the heating roller and/or the number of the heating rollers which are used. The drying unit  30  of the image forming apparatus  100  according to this embodiment is able to optimize the drying strength for the printing medium based on the type of printing medium, because the drying unit  30  is able to control the drying strength. Furthermore, the drying unit  30  of the image processing unit  100  according to this embodiment is able to prevent the contraction of the printing medium by preventing excessive drying of the pre-processing liquid. The drying unit  30  is also able to prevent degradation of image quality by preventing the under drying of the pre-processing liquid. This is accomplished by controlling the drying strength of the pre-processing liquid drying unit  31  based on the type of printing medium. That is, the image forming apparatus  100  according to this embodiment is able to improve the image quality (printing quality). 
     The drying unit  30  of the image forming apparatus  100  according to this embodiment is able to improve the image quality because the degradation of the fastness property of the image is prevented by the prevention of under drying of the post-processing liquid. This is accomplished by controlling the drying strength of the post-processing liquid drying unit  32  based on the type of printing medium. Furthermore, the drying unit  30  of the image forming apparatus according to this embodiment is able to prevent the contraction of the printing medium by preventing over drying. This is accomplished by controlling the drying strength of the post-processing liquid drying unit  32  based on the type of printing medium. 
     The ink may include an additive such as glycerin for maintaining the physical property values, such as viscosity and surface tension, of the ink in order that the inkjet image forming apparatus is able to eject ink droplets having the same condition. When prepared ink is used, the penetrability of the ink and glossiness of the printed image will be different according to the type of printing medium. The drying unit  30  of the image forming apparatus  100  according to this embodiment is able to optimize the drying of the pre-processing liquid or post processing liquid to the ink when the image forming unit  40  uses low penetrability ink. This enables the drying unit  30  according to this embodiment to prevent the occurrence of problems such as the degradation of image quality due to under drying of the pre-processing liquid, and the peeling off of part of the image on the printing medium due to scrapping against an object (e.g., the other printing medium) before the post-processing liquid is dry. The drying unit  30  according to this embodiment is able to improve the image quality (printing quality) by preventing the contraction of the printing medium due to over drying, when the image forming unit  40  uses high penetrability ink. 
     The drying unit  30  according to present invention is not limited to using the heating roller as the drying method. That is, the drying unit  30  is able to use any drying method such as an infrared ray drying method, a microwave drying method, or a hot-air drying method. The drying unit  30  is able to use a plurality of methods in combination. Furthermore, the drying unit  30  is able to heat (pre-heat) the sheet roll Md (printing medium) before the pre-processing unit  20  applies the pre-processing liquid. 
     The Configuration of the Image Forming Unit 
     The image forming unit  40  forms an image on a printing medium. The image forming unit  40  of this embodiment forms an image on a surface of the sheet roll Md by ejecting recording liquid droplets (ink or the like) on the sheet roll Md which was dried by the drying unit  30 . 
     An example of an external structure of the image forming unit  40  will be described with reference to  FIGS. 4 and 5 .  FIG. 4  is a schematic plan view showing an example of the image forming unit  40  and a post-processing unit  50  of the image forming apparatus  100  according to this embodiment.  FIG. 5  is a schematic plan view showing an example of a head unit of an ejecting head for ejecting the black color ink of the image forming unit  40 . 
     As shown in  FIG. 4 , the image forming unit  40  is able to use full-line heads. That is, the image forming unit  40  includes four ejecting heads  40 K,  40 C,  40 M, and  40 Y for different colors, black (K), cyan (C), magenta (M), and yellow (Y), in this order from the upstream to the down stream in a printing medium conveyance direction Xm. 
     The ejecting head  40 K for ejecting the black (K) color ink includes four head units  40 K- 1 ,  40 K- 2 ,  40 K- 3 ,  40 K- 4 , which are arranged in a staggered manner in the direction perpendicular to the printing medium conveyance direction Xm. This enables the image forming apparatus  40  to form an image in the entire width image forming range (printing range) of the sheet roll Md (printing medium). A description of the configuration of the other ejecting heads  40 C,  40 M, and  40 Y is omitted due to the similarities to the ejecting head  40 K. 
       FIG. 5  is an enlarged plan view showing a head unit  40 K- 1  of the ejecting head  40 K for ejecting the black color ink of the image forming unit  40 . 
     As shown in  FIG. 5 , the head unit  40 K- 1  has a plurality of ejection openings  40 N (nozzles, printing nozzles) on the nozzle face. The plurality of ejection openings  40 N are arranged along a longitudinal direction of the head unit  40 K- 1 , and form the nozzle array. Additionally, the head unit  40 K- 1  may have a plurality of nozzle arrays. 
     A cross sectional view showing the ejecting head of the image forming unit  40  will be described with reference to  FIGS. 6 and 7 .  FIG. 6  is a cross sectional view showing an example of the ejecting head in the longitudinal direction of a liquid chamber  40 F of the image forming unit  40 .  FIG. 7  is a cross sectional view showing the ejecting head in the lateral direction (nozzle sequence direction) of the liquid chamber  40 F of the image forming unit  40 .  FIG. 7  is a cross section view when viewed along a line SC 1  in  FIG. 6 . 
     As shown in  FIG. 6 , the ejecting head is configured with a nozzle communication channel  40 R that is a flow channel communicating with a nozzle  40 N for ejecting a recording liquid droplet (ink droplet). The ejecting head is provided by jointing and stacking a flow channel plate  41 , which is formed, for example, by anisotropically etching a single crystal silicon substrate. The ejecting head also is provided by a vibrating plate  42 , which is jointed to the lower surface of the channel plate  41  and formed by means of, for example, nickel electroforming, and a nozzle plate  43  jointed to the top surface of the flow channel plate  41 . A liquid chamber  40 F is also provided that is a pressure generating chamber and an ink supplying port  40 S is provided for supplying ink to the liquid chamber  40 F through a fluid resistance part (supplying channel). The ink supplying port  40 S also communicates with a common liquid chamber  40 C, and the like. 
     Also, there is provided two lines of laminated-type piezoelectric elements  45 P (that are not shown in the figures) acting as electromechanical elements which are pressure generating devices  45  (actuator devices) that pressurize ink in the liquid chamber  40 F by deforming the vibrating plate  42 . Also is provided a base substrate  45 B for jointing and fixing the piezoelectric elements  45 P. 
     Additionally, supporting pillar parts are provided between the piezoelectric elements  45 P. 
     The supporting pillar parts are parts that are formed together with the piezoelectric elements  45 P by dividing and processing each piezoelectric member. These pillars are simple supporting pillars since no driving voltage is applied thereon. 
     Also, FPC cables  45 C on which driving circuits (driving IC) are mounted (not shown in the figures) are connected to the piezoelectric elements  45 P. 
     The peripheral portion of the vibrating plate  42  is connected to a frame member  44 . Recesses are provided for a perforation part for accommodating an actuator unit. The actuator unit is composed of the piezoelectric elements  45 P, the base substrate  45 B and the like. The common liquid chamber  40 C and an ink supply port  40 IN for supplying ink from the outside the common liquid chamber  40 C and the actuator unit are each formed on the frame member  44 . 
     The frame member  44  is formed by means of injection molding of, for example, a thermosetting resin such as epoxy-type resins or a poly(phenylene sulphite). 
     Herein, the flow channel plate  41  is provided by forming recesses and holes which are provided for the nozzle communication channel  40 R and the liquid chamber  40 F. The recesses and holes are formed by, for example, anisotropically etching a single crystal silicon substrate with a crystallographic orientation (110) using an alkaline etching liquid such as an aqueous solution of potassium hydroxide (KOH). However, the present embodiment is not limited to a single crystal silicon substrate and other substrates such as a stainless substrate and photosensitive resins may also be used. 
     The vibrating plate  42  is formed from a metal plate of nickel and fabricated by, for example, an electroforming method (electrocasting method). However, other metal plates, jointing members of a metal and resin plates, and the like may also be used. 
     The piezoelectric elements  45 P and the supporting pillar parts are jointed to the vibrating plate  42  with a bonding material and the frame member  44  is further jointed with a bonding material. 
     The nozzle plate  43  includes a nozzle with a diameter of 10-30 μm which is formed so as to correspond to each liquid chamber  40 F. The nozzle plate  43  is jointed to the flow channel plate  41  with a bonding material. The nozzle plate  43  is formed such that a water-repellent layer is formed on the top surface of a desired layer on the surface of a nozzle forming member made of a metal member. 
     As shown in  FIG. 7 , the piezoelectric element  45 P is a laminated-type piezoelectric element (herein, a PZT) provided by alternately laminating piezoelectric materials  45 Pp and internal electrodes  45 Pe. 
     A separate electrode  45 Pei and a common electrode  45 Pec are connected to each of internal electrodes  45 Pe, which are alternately connected to the different end faces of the piezoelectric element  45 P. 
     Additionally, in this embodiment, there is provided a configuration such that ink in the liquid chamber  40 F is pressurized by deforming the piezoelectric element  45 P in directions of d 33  (i.e. a piezoelectric coefficient) as the directions of piezoelectricity. There may also be provided a configuration such that ink in the pressurized liquid chamber  40 F is pressurized by deforming the piezoelectric element  45 P in directions of d 31  (i.e. another piezoelectric coefficient) as directions of piezoelectricity. 
     Also, there may also be provided a configuration in which one line of piezoelectric elements  45 P is provided on one substrate  45 B. 
     In the above configured liquid ejecting head, for example, when a voltage, applied to the piezoelectric element  45 P, is lowered relative to a reference electric potential, the piezoelectric element  45 P is contracted. This results in the vibrating plate  42  being lowered thereby increasing the volume of the liquid chamber  40 F, such that ink flows into the liquid chamber  40 F. Subsequently, the voltage applied to the piezoelectric element  45 P is increased so that the piezoelectric element  45 P extends in the directions of lamination, and the vibrating plate  42  is deformed toward the direction of the nozzle  40 N. This results in a decrease in the volume of the liquid chamber  40 F. Thereby, the recording liquid (ink) in the liquid chamber  40 F is pressurized resulting in the ejection (jet) of a drop of recording liquid (ink) from the nozzle  40 N. 
     When the voltage applied to the piezoelectric element  45 P is set back to the reference electric potential, the vibrating plate  42  is restored to the initial state and the liquid chamber  40 F expands generating a negative pressure. The inside of the liquid chamber  40 F is then once again filled with recording liquid (ink) from the common liquid chamber  40 C. 
     After the vibration of a meniscus surface at the nozzle  40 N is damped and is stabilized, transition to an operation for the next liquid drop ejection is made. 
     Additionally, the manner of driving the head is not limited to the above example (pull-push-ejection) but pull-ejection or push-ejection may also be used depending on a manner of providing a driving wave pattern. 
     Accordingly, the image forming apparatus  100  according to this embodiment is able to form a full-color image or a monochrome image in the entire width image forming range using the image forming unit  40  (the ejecting units  40 K,  40 C,  40 M, and  40 Y) during a single conveyance of the printing medium (sheet roll Md). 
     Additionally, the pressure generating devices  45  of the present invention are not limited to the above described example (the piezoelectric element  45 P). That is, the pressure generating device  45  may include, for example, a thermal actuator including an electrothermal converter element such as a heating resistor or the like applying a phase change in a liquid by film boiling. The pressure generating device  45  may also include a shape memory alloy actuator that applies metallic phase change by a temperature variation, or an electrostatic actuator that applies electrostatic force generating a pressure for jetting a liquid droplet. 
     The Configuration of the Post-Processing Apparatus 
     The post-processing unit  50  treats the printing medium on which an image has been formed. In this embodiment, the post-processing unit  50  treats a surface of the sheet roll Md on which an image was formed by the image forming unit  40 . The post-processing unit  50  treats the surface using a post-processing liquid. 
     As shown in  FIG. 4 , the post-processing unit  50  in this embodiment is arranged downstream from the image forming unit  40  in a printing medium conveyance direction Xm. The post-processing unit  50  includes post-processing head units  50 H which are arranged in a staggered manner in the direction perpendicular to the printing medium conveyance direction Xm. Furthermore, the post-processing unit  50  controls the ejection (application) amount of the post-processing liquid by controlling a driving wave pattern input to the post-processing head units  50 H. This configuration enables the post-processing unit  50  to eject (apply) the post-processing liquid to the entire width image forming range (printing range) of the sheet roll Md (printing medium). A description of the configuration of post-processing head unit  50 H will be omitted due to the similarities to the configuration of the image forming unit  40  ( FIGS. 4 to 7 ). 
     The post-processing is a process of ejecting (depositing) the post-processing liquid onto the sheet roll Md (printing medium). The post-processing liquid is deposited in the shape of dots or stripes. This enables an improvement in the abrasion resistance, glossiness, and preservation stability (the environmental resistance, the water resistance, and the gas resistance, or the like) of the printing medium on which image was formed. As shown in  FIG. 8 , when the post-processing unit starts the post-processing, a surface of the sheet roll Md has the pre-processing liquid  20 L and the ink  40 Ink for forming an image applied thereon. The post-processing unit  50  of the image forming apparatus  100  according to this embodiment performs the process of ejecting (depositing) the post-processing liquid  50 L onto the sheet roll Md on which the image was formed. 
     Furthermore, the post-processing unit  50  of the image forming apparatus  100  according to this embodiment is able to eject the post-processing liquid  50 L onto a smaller area than the surface area on which the pre-processing liquid  20 L was applied. The post-processing unit  50  of the image forming apparatus  100  according to this embodiment is also able to eject the post-processing liquid  50 L onto a smaller area than the surface area on which the image was formed. 
     That is, the post-processing liquid  50 L is ejected (deposited) to a smaller area than the surface area on which the pre-processing liquid  20 L was applied. In  FIG. 8 , the ink  40 Ink is ejected onto the entire area, and the post-processing liquid  50 L is ejected (deposited) to a smaller area than the entire area. 
     Additionally,  FIG. 8  illustrates that the post-processing liquid  50 L is formed in the shape of dots. However, the post-processing liquid may also be formed in the shape of stripes in the direction perpendicular to the cross section. 
     As shown in  FIG. 8 , this embodiment describes that the post-processing liquid  50 L is ejected (deposited) onto a smaller area than the surface area on which the image is formed within the area in which the image is formed. However, the post-processing liquid  50 L may be ejected (deposited) onto an area in which an image is not formed. In addition, the post-processing liquid  50 L may not be ejected (deposited) onto the area in which an image is not formed. 
     When the printing medium, which is formed according to the shape shown in  FIG. 8 , is scraped against an object, a surface part of a layer of the post-processing liquid  50 L is scraped against the object. Thus, the post-processing liquid  50 L prevents not only the ink  40 Ink of the area on which the post-processing liquid  50 L is applied from peeling off, but also the ink  40 Ink of the area on which the post-processing liquid  50 L is not applied from peeling off, because the layer of the post-processing liquid  50 L has a greater thickness. 
     Accordingly, the image forming apparatus  100  according to an embodiment of present invention can eject (deposit) the post-processing liquid  50 L using the post-processing unit  50  onto the printing medium (sheet roll Md) on which an image was formed. This enables the image forming apparatus  100  according to this embodiment to prevent the image (ink) which is printed on the printing medium (sheet roll Md) from peeling off by being scraped against an object (e.g., the other printing medium). Thus, the ink is better maintained as compared with when the post-processing liquid is not ejected (not deposited). That is, the image forming apparatus  100  is able to improve the abrasion resistance of the image formed on the printing medium by using the features of the post-processing unit  50 . 
     The image forming apparatus  100  is able to improve the quality of image formed on the printing medium, because the post-processing unit  50  is able to deposit (eject) the post-processing liquid  50 L onto the printing medium (sheet roll Md) on which an image was formed. That is, the image forming apparatus  100  is able to reduce problems such as bleeding of the image, problems related to image density, problems related to image tone, an ink strike-through, problems related to water resistance, or problems related to environmental resistance. This reduction is due to the post-processing unit  50  depositing (eject) the post-processing liquid  50 L onto the printing medium on which an image was formed. 
     The post-processing unit  50  of the image forming apparatus  100  according to this embodiment preferably ejects (deposits) the post-processing liquid  50 L onto the area of the sheet roll Md on which an image was formed, as the post-processing method. Furthermore, the post-processing unit  50  preferably changes the ejection amount of the post-processing liquid  50 L and/or the method of ejecting, based on the type and/or the penetrability and/or the glossiness of the printing medium, and/or type of the printing medium, and/or the application amount of the pre-processing liquid by the pre-processing unit  20 . 
     The post-processing unit  50  according to this embodiment is able to eject the post-processing liquid at the amount which is needed, in the shape of dots if needed, in the shape of stripes if needed, and/or to the area where needed. 
     Specifically, the post-processing unit  50  is able to eject the post-processing liquid SOL onto any area described as follows. The post processing unit  50  is able to eject onto the area available for further image forming. The post processing unit  50  is able to eject onto the area on which an image was formed. The post processing unit  50  is able to eject onto the area on which ink droplets were ejected. The post-processing unit is also able to eject onto a slightly (1 dot or 2 dots) larger area than the area on the sheet roll Md (printing medium) on which an image was formed. Furthermore, the post-processing unit is able to eject onto some percentage of the selected area (as the shape of dots or stripes). 
     The percentage may be from 5 to 50 percent. The percentage may be determined by the experiment or by numerical calculations. 
     The post-processing unit  50  is able to determine the ejection area using any determination method described as follows. The post-processing unit  50  is able to determine based on the print coverage rate. The post-processing unit  50  is able to determine based on the amount of ejecting of the post-processing liquid  50 L. The post-processing unit  50  may also determine that the post-processing unit calculates the amount of ejecting of the post-processing liquid or the print coverage rate based on input information (printing image data or the like). The post-processing unit  50  then determines the ejection area based on the ejection amount of the post-processing liquid or the print coverage rate. 
     Accordingly, the post-processing unit  50  of the image forming apparatus according to an embodiment of present invention is able to eject (deposit) onto an area related to the area on which an image was formed. This enables the image forming apparatus  100  according to this embodiment to shorten the post-processing and drying time of the post-processing liquid. As a result, the image forming apparatus  100  according to this embodiment is able to reduce the amount of post-processing liquid as compared with the case in which the post-processing liquid is applied (ejected) to the entire surface of the printing medium. Furthermore, the image forming apparatus  100  according to this embodiment is able to reduce the cost of post-processing by reducing the amount of post-processing liquid as compared with the case in which the post-processing liquid is applied (ejected) to the entire surface of the printing medium. 
     Additionally, the post-processing method of the post-processing unit  50  is not particularly limited and is able to be appropriately selected according to the type of post-processing liquid. The post-processing method of the post-processing unit  50  is able to correspond to the pre-processing method of the pre-processing unit  20  or the ink ejecting method of the image processing unit  40 . Furthermore, from the perspective of downsizing of the image forming apparatus and the perspective of the storage stability of the post-processing liquid, the post-processing method of the post-processing unit  50  is preferably the same method as the ink ejecting method of the image forming unit. In case of ejecting the post-processing liquid, the post-processing liquid preferably includes a water-soluble organic solvent. The water-soluble organic solvent may include a wetting agent. The wetting agent is added for the purpose of preventing clogging in the nozzle of the ejecting head. Such clogging is caused by the drying of the recording liquid (ink) in the ink ejecting method of the image forming unit  40 . 
     The amount of the post-processing liquid on the sheet roll Md after drying is preferably from 0.5 g/m2 to 10 g/m2. The amount of the post-processing liquid on the sheet roll Md after drying is more preferably from 2 g/m2 to 10 g/m2. Additionally, when the amount of the post-processing liquid on the sheet roll Md after drying is less than 0.5 g/m2, the quality of the image (e.g., the abrasion resistance, glossiness, and preservation stability (e.g., the environmental resistance, the water resistance, and the gas resistance, or the like)) may be reduced. When the amount of the post-processing liquid on the sheet roll Md after drying is more than 10 g/m2, the drying characteristics of the layer of the post-processing liquid (a protective layer) may be reduced (e.g., it may take a long time to dry). Furthermore, when the amount of the post-processing liquid on the sheet roll Md after drying is more than 10 g/m2, the quality of the image may not be improved any further, which may be economically unfavorable. 
     The post-processing unit  50  according to this embodiment is able to use a treating liquid which includes a material forming a clear protective layer on the sheet roll Md (printing medium) as the post-processing liquid. The treating liquid, which includes a material forming a clear protective layer, includes a water-based resin (a water-soluble resin or a water-dispersible resin), the water-soluble organic solvent (a wetting agent), a penetrating agent, a surfactant, water, and/or the other components. The post-processing liquid may be an ultraviolet curing resin composition and/or a thermoplastic resin composition. Furthermore, for improving the glossiness and fixability, the post-processing liquid is preferably a thermoplastic resin emulsion. This enables post-processing unit  50  to improve the glossiness of a surface of the sheet roll Md on which an image was formed, or to protect the surface of the sheet roll Md by the resin layer, based on the ejecting (applying) method. 
     Any type of water-based resin may be used depending on the purpose. For example, the following water-based resins may be used: acrylic resin, styrene-acrylic resin, urethane resin, acylic silicone resin, a fluorine resin. The amount of water contained in the water based resin in the protective layer is preferably from 1% by mass to 50% by mass. Furthermore, when ejecting the post-processing liquid from the ejecting head, the amount of water contained in the water based resin in the protective layer is preferably from 1% by mass to 30% by mass. Additionally, when the amount of water contained in the water based resin is greater than the 50% by mass, viscosity of the post-processing liquid may be too high. When the amount of water contained in the water based resin is less than the 1% by mass, the amount of energy required by the post-processing unit for drying the water in the post-processing liquid may increase. 
     The average particle diameter of the water based resin in the post-processing liquid relates to the viscosity of the post-processing liquid. When the average particle is smaller the viscosity is greater. Accordingly, in order to prevent too great a viscosity of the post-processing liquid, the average particle diameter of the water based resin is preferably larger than 50 nm. 
     When the average particle diameter of the water based resin in post-processing liquid is tens of nano meters, the average particle diameter may be larger than the nozzle diameter. However, the average particle diameter is preferably smaller than the nozzle diameter (a diameter of the ejection opening  40 N in  FIG. 4 ). In addition, even though the average particle diameter of the water based resin in the post-processing liquid may be smaller than the diameter of the nozzle, when the water based resin merely includes any large diameter particle, the ability to eject may be deteriorated. 
     Accordingly, the average particle diameter of the water based resin in post-processing liquid is preferably smaller than 200 nm, more preferably smaller than 150 nm. 
     When using the water-soluble organic solvent (a wetting agent), the amount of water contained in the water-soluble organic solvent in post-processing liquid is not particularly limited. The amount of water contained in the water-soluble organic solvent may be from 10% by mass to 80% by mass. The amount of water contained in the water soluble organic solvent is preferably from 15% by mass to 60% by mass. The water-soluble organic solvent (a wetting agent) is for example, 1,3-butadiene, glycerin, or the like. 
     Additionally, when the amount of water contained in the water-soluble organic solvent is greater than 80% by mass, the drying characteristics of the post-processing liquid on the printing medium may be deteriorated. When the amount of water contained in the water-soluble organic solvent is less than 10% by mass, the components of the post-processing liquid may be changed as a result of mixing with the pre-processing liquid. 
     The penetrating agent and surfactant are not limited to particular chemicals. The penetrating agent is for example, 2-ethyl-1,3-hexanediol or the like. The surfactant is for example, polyethylene oxide end-capped with perfluoroalkyl or the like. As the penetrating agent and the surfactant used by the post-processing unit  50  the penetrating agent and surfactant included in the pre-processing liquid used by the pre-processing unit  20 , and the ink used by the image forming unit  40  may each be arbitrarily selected. 
     Additionally, the post-processing liquid may include other components. The post-processing liquid may include, for example, wax, pH adjuster, antimicrobial agent, surface modifier, or antiforming agent. 
     The wax is, for example, polyethylene wax or the like. The pH adjuster is, for example, 2-amino-2-ethyl-13-propanediol or the like. The antimicrobial agent is, for example, 1,2-benzothiazolyl-3-one or the like. The surface modifier is, for example, polyether modified poly-dimethyl-siloxane (BYK-Chemie) or the like. The antiforming agent is, for example, 2,4,7,9-Tetramethyl-4,7-decanediol or the like. 
     The Configuration of the Sheet Discharging Unit 
     The sheet discharging unit  60  discharges the printing medium on which an image has been formed. As shown in  FIG. 1 , the sheet discharging unit  60  of this embodiment includes a sheet holder  61  and a plurality of conveyance rollers  62 . The sheet discharging unit  60 , using the conveyance rollers, rolls up the sheet roll Md on the roller of the sheet holder. 
     Additionally, when the pressure on the sheet roll Md is high during the process of the sheet roll Md being rolled up on the roller of the sheet holder  62 , a drying unit for drying the sheet roll Md may be disposed adjacent to the entrance of the sheet holder  62  in order to prevent a transfer of the image to the reverse side of the sheet. 
     The Configuration of the Controlling Unit 
     The controlling unit  70  controls the action of the image forming apparatus  100 . The controlling unit of this embodiment instructs each component in the image forming apparatus  100 , and controls the action of the each component. The controlling unit  70  according to this embodiment will be described with reference to  FIGS. 9 to 13 . 
     Additionally, the image processing unit  100  may be a production printing system. The production printing system is a printing system which is able to print (form an image) to large volume printing matter (document) in a short period of time by efficiently controlling the job or the printing of the image data. Specifically, the image forming apparatus  100  (the controlling unit) according to this embodiment includes a plurality of apparatuses. One apparatus controls the order of printing job data, or transforms the printing job data to raster image data (RIP process). The other apparatus performs the printing based on the raster image data. 
     The image forming apparatus  100  (controlling unit  70 ) constructs a workflow system for managing production of print job data in order to distribute the printing matter. That is, the image forming apparatus  100  (controlling unit  70 ) is able to expedite the workflow process by distributing the process among the plurality of apparatuses. 
     As shown in  FIG. 9 , the controlling unit  70  of the image forming apparatus  100  according to this embodiment includes a superordinate apparatus  71  (DFE, digital front end, RIP, raster image processor or the like) and a printer control apparatus  72 . The superordinate apparatus  71  produces the raster image data (RIP process), for example. The printer control apparatus  72  is included in a printing apparatus for printing. The superordinate apparatus  71  and the printer control apparatus  72  are connected via a plurality of data lines  70 LD and a plurality of control lines  70 LC. 
     The superordinate apparatus  71  and the printer control apparatus  72  of the controlling unit  70  according to this embodiment will be explained in the following order. 
     The Superordinate Apparatus 
     The superordinate apparatus  71  is the apparatus that produces the raster image data (RIP process) based on the print job data (printing data, job data or the like) which is received from the host apparatus. That is, the superordinate apparatus  71  produces the raster image data (hereinafter referred to as printing image data) corresponding to the ink colors, based on the printing data. The printing image data includes the data relating to the ejection of the post-processing liquid by the post-processing unit  50  (hereinafter referred to as post-processing liquid image data). 
     The superordinate apparatus  71  produces data for controlling the printing action (hereinafter referred to as control information data), based on the print job data or the information of the host apparatus. The control information data includes the printing type, the printing form, the feeding and discharging of the sheet information and, the surface order of the printing, the size of the sheet for printing, the size of the printing image data, the resolution, the type of the sheet, the tonal range, the color information, the number of pages or the like. The control information data includes the ejection data of the post-processing liquid which is ejected by the post-processing unit  50  (hereinafter referred to as post-processing control data). 
     As shown in  FIG. 10 , the superordinate apparatus  71  of this embodiment includes a CPU (Central Processing Unit)  71   a , ROM (Read Only Memory)  71   b , RAM (Random Access Memory)  71   c , and HDD (Hard Disk Drive)  71   d . The superordinate apparatus  71  includes an external interface  71   e , a control information interface  71   f , and an image data interface  71   g . Moreover, the superordinate apparatus  71  includes a bus  71   h  which connects to the CPU  71   a  etc. That is, the CPU  71   a  etc. in the superordinate apparatus  71  can communicate via the bus  71   h.    
     The CPU  71   a  controls the entire superordinate apparatus  51 . The CPU  71   a  controls the action of the superordinate apparatus  71  by using a control program stored in the ROM  71   b  and/or HDD  71   d.    
     The ROM  71   b , the RAM  71   c , and the HDD  71   d  store the data or the like. The ROM  71   b  and/or the HDD  71   d  originally store the control program for controlling the CPU  71   a . The RAM  71   c  is used as the work memory of the CPU  71   a.    
     The external interface  71   e  controls communication with the external image forming apparatus  100 . The external interface  71   e  is able to control the communication corresponding to TCP/IP (Transmission Control Protocol/Internet Protocol). 
     The control information interface  71   f  controls the communication of control information data. The control information interface  71   f  is able to control the communication corresponding to PCI Express (Peripheral Component Interconnect Bus Express). 
     The image data interface  71   g  controls the communication of printing image data. The image data interface  71   g  is able to control communication corresponding to PCI Express. The image data interface  71   g  includes a plurality of channels corresponding to each color of the printing image data. 
     The superordinate apparatus  71  of the controlling unit  70  according to this embodiment receives the print job data from the host apparatus by the external interface  71   e . The superordinate apparatus  71  then stores the print job data in the HDD  71   d  using the CPU  71   a . The superordinate apparatus  71  reads the print job data from the HDD  71   d  using the CPU  71   a . Furthermore, the superordinate apparatus  71  produces a plurality of raster image data of the each color (Yellow (Y), Cyan (C), Magenta (M), and Black (B)). The superorinate apparatus  71  then stores each color of the raster image data to the RAM  71   c . At this time, the superordinate apparatus  71  (controlling unit  70 ) is able to produce each color raster image data by rendering the PDL (Page Description Language) as the RIP processing, which the superordinate apparatus  71  then stores to the RAM  71   c.    
     Next, the superordinate apparatus compresses and encodes each color raster image data which is then stored in HDD  71   d  of the superordinate apparatus  71 . 
     When the print controlling apparatus starts the print action, the superordinate apparatus  71  (CPU  71   a ) reads each raster image data from the HDD  71   d . The superordinate apparatus  71  then decodes each raster image data and stores the result to the RAM  71   c . The superordinate apparatus  71  next reads each color raster image data from the RAM  71   c  and outputs each color raster image data to the printer control apparatus  72  via each channel of the image data interface  71   g . The superordinate apparatus  71  is able to output the printing image data to the printer control apparatus  72  via a plurality of data lines  70 LD ( 70 LD-Y,  70 LD-C,  70 LD-M and  70 LD-K) shown in  FIG. 11  as corresponding to the respective colors. 
     The superordinate apparatus  71  sends and receives the control information data to/from the printer control apparatus  72  via the control information interface  71   f  (control lines  70 LC) based on the progression of the printing action. 
     Furthermore, when the printer control apparatus starts the post processing, the superordinate apparatus  71 , according to this embodiment, reads the encoded post-processing liquid image data from the HDD using the CPU  71   a . The superordinate apparatus  71  outputs this information to the printer control apparatus  72  via data lines  70 LD-P ( FIG. 11 ). 
     The Printer Control Apparatus 
     The printer control apparatus  72  of the controlling unit  70  according to an embodiment of present invention controls the action of image forming on the printing medium based on the printing image data and the control information data. The printer control apparatus  72  of this embodiment includes the printer controller  72 C and the printer engine  72 E. 
     The printer controller  72 C controls the action of the printer engine  72 E. The printer controller  72 C sends and receives the control information data etc. to/from the superordinate apparatus  71  via the control line  70 LC. The printer controller  72 C sends and receives the control information data etc. to/from the printer engine  72 E via the control line  72 LC. This enables the printer controller  72 C to write the various printing conditions which are included the control information data to the register of print control unit  72 Cc, and store these printing conditions. The printer controller  72 C is able to control the printer engine  72 E based on the control information data and execute printing based on the print job data (control information data). 
     As shown in  FIG. 11 , the printer controller  72 C of this embodiment includes a CPU  72 Cp and the print control unit  72 Cc. The CPU  72 Cp and the print control unit  72 Cc are connected via a bus  72 Cp in the printer controller  72 C. The bus  72 Cb is connected to the control lines  70 LC via a communication interface. 
     The CPU  72 Cp controls the action of the entire printer control apparatus  72  using the control program in ROM. The print control unit  72 Cc sends and receives a command or the status information to/from the printer engine  72 E based on the control information data which is received from the superordinate apparatus  71 . This enables print control unit  72 Cc to control the action of the printer engine  72 E. 
     The printer engine  72 E controls the action of forming an image on the printing medium based on the printing image data, which is received from the superordinate apparatus  71  and the control information data, which is received from the printer controller  72 C. The printer engine  72 E controls the action of the post-processing based on the printing image data (post-processing liquid image data), which is received from the superordinate apparatus  71  and the control information data (post-processing control data), which is received from the printer controller  72 C. 
     As shown in  FIG. 11 , the printer engine  72 E is connected to a plurality of data lines  70 LD ( 70 LD-Y,  70 LD-C,  70 LD-M,  70 LD-K, and  70 LP-P). The printer engine  72 E receives the printing image data from the superordinate apparatus  71  via the plurality of data lines ( 70 LD-C) or the like. This enables the printer engine  72 E to control the action of image data formation and the performance of the post-processing based on the received printing image data. 
     The printer engine  72 E of this embodiment includes a plurality of data storing units  72 EC,  72 EM,  72 EY,  72 EK, and  72 EP. The printer engine  72 E includes an image output unit  72 Ei which receives data from the data storing unit  72 C etc., and a conveyance control unit  72 Ec which controls the conveyance of the printing medium. Furthermore the printer engine  72 E of this embodiment includes a post-processing liquid output unit  72 Ep which receives the post-processing liquid image data from the data storing unit  72 EP, and a post-processing drying control unit  72 Epb which controls the drying unit  30  ( FIG. 1 ). 
     Additionally, the printer engine  72 E may include a pre-processing control unit  72 Epc, a pre-processing drying control unit  72 Epd, and pre-roll-up drying control unit  72 Epe. 
     The configuration of the data storing unit  72 EC will be explained with reference to  FIG. 12 . Additionally, the configuration of the other data storing units  72 EM,  72 EY,  72 EK, and  72 EP has been omitted due to the similarity between the configuration of the data storing unit  72 EC. 
     As shown in  FIG. 12 , the data storing unit  72 EC includes a logic circuit  72 ECl and a memory unit  72 ECm. The data storing unit  72 EC (the logic circuit  72 ECI) is connected to the superordinate apparatus  71  via data line  70 LD-C. The data storing unit  72 EC (the logic circuit  72 ECI) is connected to the printer controller  72 C (print control unit  72 Cc) via control line  72 LC. 
     The logic circuit  72 ECl stores the printing image data to the memory unit  72 ECm, which is output from the superordinate apparatus  71 , based on the control signal which is output from the printer controller  72 C (print control unit  72 Cc). Based on the control signal, which is output from the printer controller (print control unit  72 Cc), the logic circuit  72 ECl reads the printing image data Ic ( FIG. 11 ) from the memory unit  72 ECm corresponding to cyan (C), and outputs to the image output unit  72 Ei. Additionally, the logic circuit  72 ECl (data storing unit  72 EP) outputs the post-processing liquid image data Ip ( FIG. 11 ) to the post-processing liquid output unit  72 Ep. 
     The memory unit  72 ECm is able to have a capacity which is able to store three pages or more of image data. The three pages of printing image data includes printing image data corresponding to the page which is received from the superordinate apparatus  71 , and printing image data corresponding to the page which is sent to the image output unit  72 Ei, and printing image data corresponding to the next page to be sent. 
     Additionally, the data storing unit  72 EC may use hardware based logical circuit which is configured by the combination of the plurality of logical circuits. This enables the data storing unit  72 EC to perform the process at a higher speed. The data storing unit  72 EC may select the process to be performed by logical determination against the control signal of the bit sequence, for example. 
     The configuration of the image output unit  72 Ei will be described with reference to  FIG. 13 . Additionally, the configuration of the post-processing liquid output unit  72 Ep has been omitted due to the similarity to the configuration of the image output unit  72 Ei. 
     As shown in  FIG. 13 , the image output unit  72 Ei includes the output control unit  72 Eic. The output control unit  72 Eic outputs each printing image data to each ejecting head  40 C,  40 M,  40 Y, and  40 K ( FIG. 4 ) corresponding to the color of the printing image data. This enables the output control unit  72 Eic to control the action of the ejecting head  40 C etc., based on the printing image data. 
     Specifically, the output control unit  72 Eic individually controls the plurality of ejecting heads  40 C,  40 M,  40 Y, and  40 K. The output control unit  72 Eic may simultaneously control the plurality of ejecting heads  40 C,  40 M,  40 Y, and  40 K, based on the printing image data (for example, Ic in  FIG. 13 ). Furthermore, the output control unit  72 Eic may control the ejecting head  40 C etc. based on the control signal, which is input from a control apparatus. The output control unit  72 Eic may control the ejecting head  40 C etc. based on an input operation of the user. 
     Accordingly, the printer control apparatus  72  inputs to the plurality of ejecting heads  40 C etc. the printing image data which is output from the superordinate apparatus using the data storing unit  72 EC and the output control unit  72 Eic. At this time, the printer control apparatus  72  is able to individually control each color printing image data. The printer control apparatus  72  is able to change the configuration of the printer engine  72 E corresponding to the number of colors in the printing image data (C, M, Y, and K or K only) or the number of ejecting heads. That is, the printer control apparatus  72  in the image forming apparatus  100  according to this embodiment is able to reduce the cost and downsize the apparatus by mounting only the needed data storing unit  72 EC and the needed ejecting head  40 C. 
     For example, when the full-color image is formed by the C, M, Y, and K, the printer control apparatus  72  in the image forming apparatus  100  according to this embodiment has all of the data storing units  72 EC etc. This enables the printer control apparatus  72  in the image forming apparatus  100  to connect to ejecting heads  40 C, etc. for each output from the data storing units  72 EC etc. by the output control unit  72 Eic. 
     For example, when the image is formed by K only, the printer control apparatus  72  in the image forming apparatus  100  may have one data storing unit  72 EK and one ejecting head  40 K in order to give priority to the cost. This enables the printer control apparatus  72  in the image forming apparatus  100  to connect to the ejecting head  40 K for the output from the data storing unit  72 EK by the output control unit  72 Eic. 
     Furthermore, for example, when the image is formed by the K only, the printer control apparatus  72  in the image forming apparatus  100  may have one data storing unit  72 EK and four ejecting heads in order to give priority to printing speed. 
     This enables the printer control apparatus  72  in the image forming apparatus  100  to connect the output from the data storing unit  72 EK to each of the four ejecting heads by the output control unit  72 Eic. 
     In this case, the printer control apparatus  72  in the image forming apparatus  100  is able to form an image at four times the speed of using only one ejecting head because one color (K) is being formed by four ejecting heads. 
     Having generally described this invention, further understanding can be obtained by reference to certain specific examples which are provided herein for the purpose of illustration only and are not intended to be limiting. 
     The First Example 
     The embodiments of the present invention will be described with reference to image forming apparatus  100 E in the first example. 
     Configurations of the image forming apparatus  100 E are shown in  FIGS. 1 to 7 . The configurations of the image forming apparatus  100 E in the foregoing embodiment will be omitted in this example due to the similarities to the configuration of the image forming apparatus  100  shown in  FIGS. 1 to 7 . 
     Configurations of a controlling unit  70  of the image forming apparatus  100 E are shown in  FIGS. 9 to 13 . The configurations of the controlling unit of the image forming apparatus  100 E in the foregoing embodiment will be omitted in this example due to the similarities to the configuration the controlling unit  70  of image forming apparatus  100  shown in  FIGS. 9 to 13 . Therefore, the same description is not repeated. 
     The controlling unit  70  of this example determines the type of the printing medium based on the user input operation to the image forming apparatus  100 E. 
     The operation of forming an image by the image forming apparatus  100 E according to this example will be described with reference to  FIG. 14 . 
     As shown in  FIG. 14 , the image forming apparatus  100 E according to this example, in step S 1401 , initiates image formation, based on print job data which is input from an external image forming apparatus. The image forming apparatus  100 E stores the printing job data, which is input to the HDD  71   d  of the superordinate apparatus  71 . 
     Then, in step S 1402 , the image forming apparatus  100 E determines the type of printing medium using controlling unit  70 , and stores (sets) the determined type of printing medium to the HDD  71   d  of the superordinate apparatus  71 . 
     At this time, the controlling unit  70  may further store information of the printing medium (a physical property value of the printing medium such as a material, a thickness, a basis weight of the paper, or the like). The controlling unit  70  may set the type of printing medium based on the type of printing medium pre-stored in the HDD  71   d  of the superordinate apparatus  71 . This enables the controlling unit  70  to read the type of printing medium at a later time by using the pre-stored type. Additionally, the image forming apparatus  100 E is able to pre-store the type of printing medium to the HDD  71   d  of the superordinate apparatus based on the user input operation. 
     Then, in step S 1403 , the image forming apparatus  100 E produces the printing image data and the control information data or the like using the superordinate apparatus  71  of the controlling unit  70 . Specifically, the superordinate apparatus  71  of the controlling unit  70  produces the print job data and the control information data based on the type of printing medium and the print job data which are stored in the HDD  71   d  or the like. 
     Next, the image forming apparatus  100 E performs step S 1404 . Additionally, the order of the step of determining the amount of pre-processing liquid (step S 1404 ) and the step of determining the amount of the post-processing liquid (step S 1405 ) may be reversed. 
     In step S 1404 , the image forming apparatus  100 E calculates the amount of pre-processing liquid (the application amount of the liquid in this example) using the controlling unit  70 . 
     Specifically, the controlling unit  70  calculates the application amount of pre-processing liquid  20 L using the pre-processing unit  20 , based on type of the printing medium. When a penetrability of the printing medium is high, the controlling unit  70  is able to raise the application amount of the pre-processing liquid  20 L. Furthermore, in case that a penetrability of the printing medium is low, the controlling unit  70  is able to reduce the application amount of the pre-processing liquid  20 L. Additionally, the image forming apparatus  100 E may select the amount of pre-processing liquid  20 L based on a user input operation using a UI (User Interface) or the like. 
     Then, in step S 1405 , the image forming apparatus  100 E calculates the amount of post-processing liquid (the ejected amount of the liquid in this example) using the controlling unit  70 . Specifically, as was similarly described above with respect to step S 1404 , the controlling unit  70  calculates the ejection amount of post-processing liquid  20 L (the amount of liquid) using the post-processing unit  50 , based on type of the printing medium. 
     That is, the controlling unit  70  is able to calculate the application amount of the pre-processing liquid  20 L based on at least the type of the printing medium, and is also able to calculate the ejection amount of the post-processing liquid  50 L based on the type of printing medium. This enables the image forming apparatus  100 E to improve the abrasion resistance by raising the ejection amount of the post-processing liquid  50 L, when the application amount of the pre-processing liquid has been raised and the abrasion resistance of the formed image is reduced. 
     Additionally, the controlling unit  70  is able to set the application amount of the pre-processing liquid  20 L to 1.5 g/m2 or more, when raising the application amount of the pre-processing liquid  20 L. The controlling unit  70  is able to set the application amount of the post-processing liquid  50 L to 1.2 g/m2 or more, when raising the application amount of the post-processing liquid  50 L. Alternatively, the controlling unit  70  is able to set the application amount of the pre-processing liquid  20 L to less than 1.5 g/m2, when reducing the application amount of the pre-processing liquid  20 L. The controlling unit  70  is able to set the application amount of the post-processing liquid  50 L to less than 1.2 g/m2, when reducing the application amount of the post-processing liquid  50 L. The controlling unit  70  does not need to perform any application or ejection, when the application amount of the pre-processing  20 L and the ejection amount of the post-processing liquid  50 L is reduced. Furthermore, the controlling unit  70  may change the application amount of the pre-processing liquid  20 L and the ejection amount of the post-processing liquid  50 L, based on the physical property value of the printing medium or the like. 
     In step S 1406 , the image forming apparatus  100 E feeds the printing medium to the pre-processing unit using the sheet feeding unit  10  ( FIG. 1 ). Additionally, the image forming apparatus  100 E may initiate step S 1406  soon after the initiation of step S 1401 . The image forming apparatus  100 E performs step S 1408  after initiating the sheet feeding. 
     In step S 1407 , the image forming apparatus  100 E performs the pre-processing using the pre-processing unit  20  ( FIG. 1 ). Specifically, the pre-processing unit  20  controls the nip pressure based on the determined application amount of the pre-processing liquid  20 L which is calculated in step S 1404  using the pressure controller  25 . In addition the application amount of the pre-processing liquid  20 L (the thickness of the liquid film etc.) is also controlled (changed) based on the calculation in step S 1404 . Additionally, the pre-processing unit  20  may control the application amount of the pre-processing liquid  20 L by changing the rotation speed of the applying roller  23  ( FIG. 2 ). 
     This enables the image forming apparatus  100 E to reduce bleeding of the formed image by controlling the application amount of the pre-processing liquid  20 L. As shown in  FIG. 15 , the image forming apparatus  100 E is able to make the granularity of the ink dots to be small by raising the application amount of the pre-processing liquid  20 L. That is, in the image forming apparatus  100 E, the granularity of the ink dots may be set to be less than a predetermined granularity Rs, by raising the application amount of the pre-processing liquid  20 L. 
     The predetermined granularity Rs may be the granularity at which it is difficult for the ink to bleed on the printing medium. The predetermined granularity Rs may be determined by experiment or by numerical calculations. The image forming apparatus  100 E then feeds the printing medium to the drying unit  30  (the pre-processing liquid drying unit  31  in  FIG. 1 ). 
     In step S 1408 , the image forming apparatus  100 E dries the printing medium using the pre-processing liquid drying unit  31  ( FIG. 1 ). The pre-processing liquid drying unit  31  controls drying strength (pre-processing liquid dry strength) based on the type of printing medium. Furthermore, the pre-processing liquid drying unit  31  is able to further control the drying strength (pre-processing liquid dry strength) using the application amount the pre-processing liquid  20 L. 
     Then, the image forming apparatus  100 E feeds the printing medium to the image forming unit  40  ( FIGS. 1, 4, 5 ). 
     In step S 1409 , as the image formation step, the image forming apparatus  100 E forms an image on a surface of the printing medium using the image forming unit  40 . The image is formed based on the printing image data which was produced (in step S 1403 ). The image forming unit  40  may further form the image taking into account the type of the printing medium. The image forming unit  40  is able to control the action of the image forming by controlling the voltage applied to the piezoelectric element  45 P (the pressure generating device in  FIGS. 6, 7 ) 
     The image forming apparatus  100 E then feeds the printing medium to the post-processing unit  50  ( FIG. 1 ). 
     In step S 1410 , as the post-processing step, the image forming apparatus  100 E treats the printing medium using the post-processing unit  50 . 
     Specifically, the post-processing unit  50  ejects (deposits) the post-processing liquid  50 L onto a specified area in the image formation area of the printing medium, based on the post-processing liquid image data (in step S 1403 ) and the ejection amount of the post-processing liquid, which was calculated (in step S 1404 ). The post-processing unit  50  is able to control the ejection amount of the post-processing liquid  50 L on the printing medium using the post-processing liquid output unit  72 Ep of the controlling unit  70 , based on the post-processing liquid image data. 
     The image forming apparatus  100 E then feeds the printing medium to the drying unit  30  (the post-processing liquid drying unit  32  in  FIG. 1 ). 
     In step S 1411 , the image forming apparatus  100 E dries the printing medium using the post-processing liquid drying unit  32  (heat roller). The post-processing liquid drying unit  32  is able to control the drying strength (post-processing liquid dry strength) based on the type of the printing medium. Furthermore, the post-processing liquid drying unit  32  is able to control the drying strength (post-processing liquid dry strength) further using the application amount of the pre-processing liquid and/or the ejection amount of the post-processing liquid. 
     In step S 1412 , the image forming apparatus  100 E discharges the printing medium using the sheet discharging unit  60  ( FIG. 1 ). 
     Finally, in the END step, the image forming apparatus  100 E completes the image forming operation. 
     The image forming apparatus  100 E according to this example is able to obtain the same effect as the image forming apparatus  100  in the embodiments described above. 
     The Second Example 
     The embodiments of the present invention will be described with reference to image forming apparatus  200 E in the second example. 
     Configurations of the image forming apparatus  200 E are shown in  FIGS. 1 to 7 . The configurations of the image forming apparatus  200 E in the foregoing embodiment will be omitted in this example due to the similarities to the configuration of the image forming apparatus  100  shown in  FIGS. 1 to 7  and the image forming apparatus  100 E of the first example. 
     Configurations of a controlling unit  70  of the image forming apparatus  200 E are shown in  FIGS. 9 to 13 . The configurations of the controlling unit of the image forming apparatus  200 E in the foregoing embodiment will be omitted in this example due to the similarities to the configuration the controlling unit  70  of image forming apparatus  100  shown in  FIGS. 9 to 13  and the image forming apparatus  100 E of the first example. Therefore, the same description is not repeated. 
     In the first example, the controlling unit  70  calculates the ejection amount of post-processing liquid based on the type of printing medium. 
     The controlling unit  70  according to this example calculates the ejection amount of the post-processing liquid based on the amount of the pre-processing liquid. 
     That is, in this example, the controlling unit  70  calculates the ejection amount of the post-processing liquid using the amount of pre-processing liquid, which is calculated based on user input information input to the image forming apparatus  200 E by a user. 
     The input information may include the type of printing medium. Furthermore, the input information may include penetrability and glossiness of the printing medium. 
     The operation of forming an image by the image forming apparatus  200 E according to this example will be described with reference to  FIG. 16 . 
     As shown in  FIG. 16 , the image forming apparatus  200 E performs steps S 1601  to S 1604  similarly to steps S 1401  to S 1404  performed by the image forming apparatus  100 E of the first example. 
     In step S 1605 , the image forming apparatus  200 E calculates the amount of post-processing liquid (ejection amount of the post processing liquid) using the controlling unit  70 . The controlling unit  70  of this example calculates the amount of post-processing liquid based on the amount of pre-processing liquid which is calculated in step S 1604 . That is, the controlling unit  70  (the image forming apparatus  200 E) calculates the application amount of pre-processing liquid based on the type of printing medium, and calculates the ejection amount of post-processing liquid based on the application amount of the pre-processing liquid. Accordingly, the image forming apparatus  200 E according to this example calculates the amount of post-processing liquid based on the type of printing medium. This is the case because the amount of the pre-processing liquid is calculated based on the type of printing medium. 
     After calculating the amount of post-processing liquid, the image forming apparatus  200 E performs steps S 1606  to S 1612  similarly to steps S 1406  to S 1412  performed by the image forming apparatus  100 E of the first example. Then, in END step, the image forming apparatus  200 E completes the image forming operation. 
     Accordingly, the image forming apparatus  200 E according to the second example is able to obtain the same effect as the image forming apparatus  100  of the above noted embodiments and the image forming apparatus  100 E of the first example. 
     The Third Example 
     The embodiments of the present invention will be described with reference to image forming apparatus  300 E in the third example. 
     Configurations of the image forming apparatus  300 E are shown in  FIGS. 1 to 7 . The configurations of the image forming apparatus  300 E in the foregoing embodiment will be omitted in this example due to the similarities to the configurations of the image forming apparatus  100  shown in  FIGS. 1 to 7 , the image forming apparatus  100 E of the first example, and the image forming apparatus  200 E of the second example. 
     Configurations of a controlling unit  70  of the image forming apparatus  300 E are shown in  FIGS. 9 to 13 . The configurations of the controlling unit of the image forming apparatus  300 E in the foregoing embodiment will be omitted in this example due to the similarities to the configurations the controlling unit  70  of the image forming apparatus  100  shown in  FIGS. 9 to 13 , the image forming apparatus  100 E of the first example, and the image forming apparatus  200 E of the second example. Therefore, the same description is not repeated. 
     In the second example, the controlling unit  70  calculates the amount of pre-processing liquid (application amount) based on the type of printing medium, and calculates the amount of post-processing liquid based on the calculated amount of pre-processing liquid. 
     The controlling unit  70  according to this example calculates the application amount of pre-processing liquid based on the type of printing medium, and calculates the amount of post-processing liquid based on the calculated amount of the pre-processing liquid. The controlling unit  70  further adjusts (re-calculates) the amount of post-processing liquid based on the type of printing medium. For example, the controlling unit  70  determines the glossiness of the printing medium based on the type of printing medium, and adjusts (re-calculates) the ejection amount of the post-processing liquid based on the glossiness. 
     The operation of image formation by the image forming apparatus  300 E according to this example will be described with reference to  FIG. 17 . 
     As shown in  FIG. 17 , the image forming apparatus  300 E performs steps S 1701  to S 1705  similarly to steps S 1601  to step S 1605  performed by the image forming apparatus  200 E of the second example. 
     Then, in step S 1706 , the image forming apparatus  300 E adjusts (re-calculates) the amount of post-processing liquid (the ejection amount) using the controlling unit  70 . The controlling unit  70  of this example re-calculates the ejection amount of post-processing liquid based on user input information input to the image forming apparatus  300 E by a user. 
     Specifically, the superordinate apparatus  71  of the controlling unit  70  first reads a type of printing medium from the HDD  71   d  or the like. Next, the controlling unit  70  re-calculates the ejection amount of post-processing liquid  50 L based on the type of printing medium and the ejection amount of post-processing liquid, which was calculated in step S 1705 . 
     Accordingly, the amount of the pre-processing liquid may be small based on the type of printing medium. For example, when the printing medium has high glossiness, and when there is great difference in glossiness between the area on which image is formed and the area on which image is not formed, the image forming apparatus  300 E is able to raise the application amount of the post-processing liquid based on the type of printing medium. That is, the image forming apparatus  300 E is able to reduce the cost of pre-processing liquid  20 L and reduce the difference in glossiness between the area on which image is formed and the area on which image is not formed by raising the ejection amount of post-processing liquid  50 L. Accordingly, the image forming apparatus  300 E is able to reduce the cost of the pre-processing liquid and improve the quality of the image. 
     After adjusting the amount of the post-processing liquid, the image forming apparatus  300 E performs steps S 1707  to S 1713  similarly steps S 1606  to S 1612  performed by the image forming apparatus  200 E of the second example. Then, in END step, the image forming apparatus  200 E completes the image forming operation. 
     Accordingly, the image forming apparatus  300 E according to the third example is able to obtain the same effect as the image forming apparatus  100  of the above described embodiment, the image forming apparatus  100 E of the first example, and the image forming apparatus  200 E of the second example. 
     The Fourth Example 
     The embodiments of the present invention will be described with reference to image forming apparatus  400 E in the fourth example. 
     Configurations of the image forming apparatus  400 E are shown in  FIGS. 1 to 7 . The configurations of the image forming apparatus  400 E in the foregoing embodiment will be omitted in this example due to the similarities to the configurations of the image forming apparatus  100 E of the first example. 
     Configurations of a controlling unit  70  of the image forming apparatus  400 E are shown in  FIGS. 9 to 13 . The configurations of the controlling unit of the image forming apparatus  400 E in the foregoing embodiment will be omitted in this example due to the similarities to the configurations the controlling unit  70  of the image forming apparatus  100 E of the first example. Therefore, the same description is not repeated. 
     The flowchart of the first example ( FIG. 14 ) does not include a step of determining drying strength (pre-processing liquid drying strength and post-processing liquid drying strength). The controlling unit  70  according to this example includes the step of determining the drying strength (pre-processing liquid drying strength and post-processing liquid drying strength) based on type of the printing medium. The step of determining the pre-processing liquid drying strength and post-processing liquid drying strength will be described as follows. 
     The operation of image formation by the image forming apparatus  400 E according to this example will be described with reference to  FIG. 18 . 
     As shown in  FIG. 18 , the image forming apparatus  400 E performs steps S 1801  to S 1805  similarly to steps S 1401  to S 1405  performed by the image forming apparatus  100 E of the first example. 
     In step S 1806 , the image forming apparatus  400 E determines the pre-processing liquid drying strength for the pre-processing liquid drying unit  31  ( FIG. 1 ) using the controlling unit  70 . In this example, the controlling unit  70  determines the pre-processing liquid drying strength based on user input information (type of the printing medium) input to the image forming apparatus  400 E by a user. 
     In step S 1807 , the image forming apparatus  400 E determines the post-processing liquid drying strength of the post-processing liquid drying unit  32  ( FIG. 1 ) using the controlling unit  70 . In this example, the controlling unit  70  determines the post-processing liquid drying strength based on user input information (type of the printing medium) input to the image forming apparatus  400 E by a user. 
     The image forming apparatus  400 E performs steps S 1808  to S 1814  similarly to steps S 1406  to S 1412  performed by the image forming apparatus  100 E of the first example. Then, in the END step, the image forming apparatus  200 E completes the image forming operation. Additionally, the method of controlling the drying strength in steps S 1810  and S 1813  has been omitted due to similarities to the image forming apparatus  100  ( FIG. 3 ) according to the above embodiment. 
     Accordingly, the image forming apparatus  400 E according to the fourth example is able to obtain the same effect as the image forming apparatus  100 E of the first example. 
     The Fifth Example 
     The embodiments of the present invention will be described with reference to image forming apparatus  500 E of the fifth example. 
     Configurations of the image forming apparatus  500 E are shown in  FIGS. 1 to 7 . The configurations of the image forming apparatus  500 E in the foregoing embodiment will be omitted in this example due to the similarities to the configuration of the image forming apparatus  200 E of the second example. 
     Configurations of a controlling unit  70  of the image forming apparatus  500 E are shown in  FIGS. 9 to 13 . The configurations of the controlling unit of the image forming apparatus  500 E in the foregoing embodiment will be omitted in this example due to the similarities to the configurations the controlling unit  70  of the image forming apparatus  200 E of the second example. Therefore, the same description is not repeated. 
     The flowchart of the second example ( FIG. 16 ) does not include a step of determining a drying strength (pre-processing liquid drying strength and post-processing liquid drying strength). The controlling unit  70  according to this example includes the step of determining the drying strength (pre-processing liquid drying strength and post-processing liquid drying strength) based on the amount of pre-processing liquid and the amount of post-processing liquid. The step of determining the pre-processing liquid drying strength and post-processing liquid drying strength will be described as follows. 
     The operation of image formation by the image forming apparatus  500 E according to this example will be described with reference to  FIG. 19 . 
     As shown in  FIG. 19 , the image forming apparatus  500 E performs steps S 1901  to S 1905  similarly to steps S 1601  to S 1605  performed by the image forming apparatus  200 E of the second example. 
     In step S 1906 , the image forming apparatus  500 E determines the pre-processing liquid drying strength of the pre-processing liquid drying unit  31  ( FIG. 1 ) using the controlling unit  70 . In this example, the controlling unit  70  determines the pre-processing liquid drying strength based on the amount of pre-processing liquid (the application amount) which was calculated in step S 1904 . 
     In step S 1907 , the image forming apparatus  500 E determines the post-processing liquid drying strength for the post-processing liquid drying unit  32  ( FIG. 1 ) using the controlling unit  70 . In this example, the controlling unit  70  determines the post-processing liquid drying strength based on the amount of post-processing liquid (the application amount) which was calculated in step S 1905 . 
     The image forming apparatus  500 E performs steps S 1908  to S 1914  similarly to steps S 1606  to S 1612  performed by the image forming apparatus  200 E of the second example. Then, in the END step, the image forming apparatus  500 E completes the image forming operation. Additionally, the method of controlling the drying strength in steps S 1911  and S 1914  has been omitted due to the similarity to the image forming apparatus  100  ( FIG. 3 ) according to the above embodiment. 
     Accordingly, the image forming apparatus  500 E according to the fifth example is able to obtain the same effect as the image forming apparatus  200 E of the second example. 
     The Sixth Example 
     The embodiments of the present invention will be described with reference to image forming apparatus  600 E of the sixth example. 
     Configurations of the image forming apparatus  600 E are shown in  FIGS. 1 to 7 . The configurations of the image forming apparatus  600 E in the foregoing embodiment will be omitted in this example due to the similarities to the configuration of the image forming apparatus  300 E of the third example. 
     Configurations of a controlling unit  70  of the image forming apparatus  600 E are shown in  FIGS. 9 to 13 . The configurations of the controlling unit of the image forming apparatus  600 E in the foregoing embodiment will be omitted in this example due to the similarities to the configurations the controlling unit  70  of the image forming apparatus  300 E of the third example. Therefore, the same description is not repeated. 
     The flowchart of the third example ( FIG. 17 ) does not include a step of determining the drying strength (pre-processing liquid drying strength and post-processing liquid drying strength). The controlling unit  70  according to this example includes the step of determining the drying strength (pre-processing liquid drying strength and post-processing liquid drying strength) based on the amount of pre-processing liquid and the amount of post-processing liquid. The step of determining the pre-processing liquid drying strength and post-processing liquid drying strength will be described as the follows. 
     The operation of image formation by the image forming apparatus  600 E according to this example will be described with reference to  FIG. 20 . 
     As shown in  FIG. 20 , the image forming apparatus  600 E performs steps S 2001  to S 2006  similarly to steps S 1701  to S 1706  performed by the image forming apparatus  300 E of the third example. 
     In step S 2007 , the image forming apparatus  600 E determines the pre-processing liquid drying strength for the pre-processing liquid drying unit  31  ( FIG. 1 ) using the controlling unit  70 . In this example, the controlling unit  70  determines the pre-processing liquid drying strength based on the amount of pre-processing liquid (the application amount) which was calculated in step S 2004 . 
     In step S 2008 , the image forming apparatus  600 E determines the post-processing liquid drying strength for the post-processing liquid drying unit  32  ( FIG. 1 ) by the controlling unit  70 . In this example, the controlling unit  70  determines the post-processing liquid drying strength based on the amount of post-processing liquid (the application amount) which was calculated in step S 2006 . 
     The image forming apparatus  600 E performs steps S 2009  to S 2015  similarly to steps S 1707  to S 1713  performed by the image forming apparatus  300 E of the third example. Then, in the END step, the image forming apparatus  600 E completes the image forming operation. Additionally, the method of controlling the drying strength in steps S 2011  and S 2014  has been omitted due to the similarities to the image forming apparatus  100  ( FIG. 3 ) according to the above embodiment. 
     Accordingly, the image forming apparatus  600 E according to the sixth example is able to obtain the same effect as the image forming apparatus  300 E in the third example. 
     The foregoing description of the embodiments of the invention has been presented for the purpose of illustration and is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Persons skilled in the relevant art can appreciate that many modifications and variations are possible in light of the above teachings. It is therefore intended that the scope of the invention be limited not by this detailed description, but rather by the claims appended hereto.