Patent Publication Number: US-11020983-B2

Title: Liquid ejecting device and liquid ejecting method

Description:
The present application is based on, and claims priority from JP Application Serial Number 2019-004983, filed Jan. 16, 2019, the disclosure of which is hereby incorporated by reference herein in its entirety. 
     BACKGROUND 
     1. Technical Field 
     The present disclosure relates to a liquid ejecting device and a liquid ejecting method. 
     2. Related Art 
     In related art, various liquid ejecting devices have been used. In such liquid ejecting devices, various types of media and inks of various compositions are used. Thus, depending on the type or the like of the medium or ink used, a phenomenon known as strike-through of the ink may occur in which a color material of the ink ejected onto the medium penetrates to the reverse side of the medium, and the color of the ink appears on the reverse side. Here, a liquid ejecting method and the like intended to suppress the strike-through of the ink is disclosed. For example, in JP-A-2000-343807, an ink recording method is disclosed that applies ink to a recording medium after a penetration enhancer was applied to the recording medium. 
     However, in recent years, medium and ink have become increasingly diverse, and even when the ink recording method disclosed in JP-A-2000-343807 is performed, there may be strike-through of the ink due to the type and the like of the medium and ink used. 
     SUMMARY 
     A liquid ejecting device according to the present disclosure for solving the above-described problem includes an ejecting unit configured to eject liquid, and a control unit configured to perform control to cause the ejecting unit to eject the liquid to apply the liquid to a medium. The ejecting unit is configured to eject, as the liquid, ink, that contains a color material, for forming an image on the medium, and inhibitor for inhibiting penetration of the color material into the medium. The control unit is configured to select a first printing mode for forming an image on the medium by applying the ink to the medium without applying the inhibitor to the medium, and a second printing mode for forming an image on the medium by applying the inhibitor to the medium and applying the ink to the medium applied with the inhibitor, and the control unit causes an amount of the ink applied per unit area in the second printing mode to be smaller than an amount of the ink applied per unit area in the first printing mode. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic side view of a liquid ejecting device according to Example 1 of the present disclosure. 
         FIG. 2  is a schematic bottom view of a head capable of being used in the liquid ejecting device according to Example 1 of the present disclosure. 
         FIG. 3  is a schematic bottom view of another type of the head capable of being used in the liquid ejecting device according to Example 1 of the present disclosure. 
         FIG. 4  is a block diagram illustrating an electrical configuration of the liquid ejecting device according to Example 1 of the present disclosure. 
         FIG. 5  is a flowchart of a liquid ejecting method that is executed using the liquid ejecting device according to Example 1 of the present disclosure. 
         FIG. 6  is a schematic side view of a liquid ejecting device according to Example 2 of the present disclosure. 
     
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     First, an overview of the present disclosure will be described. 
     A liquid ejecting device according to a first aspect of the present disclosure for solving the above-described problem includes an ejecting unit capable of ejecting liquid, and a control unit configured to perform control to cause the ejecting unit to eject the liquid to apply the liquid to a medium. The ejecting unit is configured to be capable of ejecting, as the liquid, ink that contains a color material and is for forming an image on the medium, and inhibitor for inhibiting penetration of the color material into the medium. The control unit is configured to select a first printing mode for forming an image on the medium by applying the ink to the medium without applying the inhibitor to the medium, and a second printing mode for forming an image on the medium by applying the inhibitor to the medium and applying the ink to the medium applied with the inhibitor, and the control unit causes an amount of the ink applied per unit area in the second printing mode to be smaller than an amount of the ink applied per unit area in the first printing mode. 
     According to the present aspect, the amount of the ink applied per unit area in the second printing mode, in which the image is formed on the medium by applying the ink to the medium applied with the inhibitor, is caused to be smaller than the amount of the ink applied per unit area in the first printing mode, in which the image is formed on the medium by applying the ink to the medium without applying the inhibitor. Specifically, the amount of ink applied per unit area in the second printing mode can be reduced, and by reducing the amount of ink applied, strike-through of the ink can be suppressed even when a medium or ink that is susceptible to the strike-through is used. 
     The liquid ejecting device according to a second aspect of the present disclosure is the liquid ejecting device of the first aspect, in which the control unit is configured to select, as the second printing mode, a single-sided printing mode for forming an image on the first surface by applying the inhibitor to a first surface of the medium and applying the ink to the first surface applied with the inhibitor, and ending the printing, and a double-sided printing mode for forming an image on the first surface by applying the inhibitor to the first surface and applying the ink to the first surface applied with the inhibitor, and subsequently forming an image on a second surface by applying the inhibitor to the second surface on an opposite side of the medium from the first surface and applying the ink to the second surface applied with the inhibitor. 
     According to the present aspect, since the single-sided printing mode and the double-sided printing mode can be selectively performed, through the single-sided printing mode, it is possible, while making the most of a basic condition of one surface of the medium, to form the image on the other surface, and through the double-sided printing mode, it is possible to suppress the strike-through of the ink and form images on both surfaces of the medium. 
     The liquid ejecting device according to a third aspect of the present disclosure is the liquid ejecting device of the second aspect, in which the ejecting unit includes a first ejecting unit capable of ejecting the liquid onto the first surface, and a second ejecting unit capable of ejecting the liquid onto the second surface. The control unit, in the double-sided printing mode, performs control to cause the first ejecting unit to eject the liquid to form an image on the first surface, and to subsequently cause the second ejecting unit to eject the liquid to form an image on the second surface. 
     According to the present aspect, the images can be formed on both surfaces of the medium using the first ejecting unit and the second ejecting unit, while favorably suppressing the strike-through of the ink. 
     The liquid ejecting device according to a fourth aspect of the present disclosure is the liquid ejecting device of the second aspect, further including an inversion mechanism for the medium. The control unit, in the double-sided printing mode, performs control to cause the ejecting unit to eject the liquid to form an image on the first surface, and to subsequently control the inversion mechanism to invert the medium, and cause the ejecting unit to eject the liquid to form an image on the second surface. 
     According to the present aspect, the images can be formed on both surfaces of the medium using the liquid ejecting device having a simple configuration provided with the single ejecting unit, while suppressing the strike-through of the ink. 
     The liquid ejecting device according to a fifth aspect of the present disclosure is the liquid ejecting device of any one of the first to fourth aspects, further including an imaging unit configured to capture an image of a back surface, that is a surface on an opposite side of the medium from a top surface, when the top surface is a surface of the medium facing the ejecting unit, and a warning unit configured to perform a warning operation by control of the control unit. The control unit determines, based on data of the image captured by the imaging unit, whether an image is formed on the back surface, and causes the warning unit to perform the warning operation in a case where it is determined that the image is formed on the back surface when the first printing mode is selected. 
     According to the present aspect, when forming the image on the top surface of the medium on which the image is formed on the back surface, it is possible to reduce a possibility of deterioration of the quality of the image formed on the back surface by the strike-through of the ink ejected onto the top surface as a result of mistakenly selecting the first printing mode. 
     The liquid ejecting device according to a sixth aspect of the present disclosure is the liquid ejecting device according to any one of the first to fifth aspects, further including a support surface configured to support the medium at a position facing the ejecting unit, and a gap changing unit configured to change a gap between the ejecting unit and the support surface. The control unit changes, based on the gap, an amount of the inhibitor applied per unit area in the second printing mode. 
     The thin medium is susceptible to the strike-through, and the thick medium is not so susceptible to the strike-through, but according to the present aspect, the amount of inhibitor applied per unit area in the second printing mode is changed based on the gap that corresponds to the thickness of the medium, and thus, the strike-through of the ink can be suppressed in accordance with the thickness of the medium. 
     The liquid ejecting device according to a seventh aspect of the present disclosure is the liquid ejecting device of any one of the first to sixth aspects, in which the inhibitor contains at least one of metal ions or saccharides. 
     Since the metal ions and the saccharides can favorably thicken the ink or coagulate the color material, according to the present aspect, the penetration of the color material into the medium can be favorably suppressed and the strike-through of the ink in the medium can be favorably suppressed. 
     A liquid ejecting method of an eighth aspect of the present disclosure is a liquid ejecting method for a liquid ejecting device including an ejecting unit configured to eject liquid and configured to eject, as the liquid, ink that contains a color material and is for forming an image on the medium, and inhibitor for inhibiting penetration of the color material into the medium. The liquid ejecting method includes causing an amount of the ink applied per unit area in a second printing mode to be smaller than an amount of the ink applied per unit area in a first printing mode, when the first printing mode for forming an image on the medium by applying the ink to the medium without applying the inhibitor to the medium, and the second printing mode for forming an image on the medium by applying the inhibitor to the medium and applying the ink to the medium applied with the inhibitor are selectable. 
     According to the present aspect, the amount of ink applied per unit area in the second printing mode, in which the image is formed on the medium by applying the ink to the medium applied with the inhibitor, is caused to be smaller than the amount of ink applied per unit area in the first printing mode, in which the image is formed on the medium by applying the ink to the medium without applying the inhibitor. Specifically, the amount of ink applied per unit area in the second printing mode can be reduced, and by reducing the amount of ink applied, the strike-through of the ink in the medium can be suppressed even when the medium or ink that is susceptible to strike-through is used, for example. 
     Embodiments of the present disclosure will be described below with reference to the accompanying drawings. 
     Example 1 (FIG.  1  to FIG.  5 ) 
     First, an outline of a liquid ejecting device  1  according to Example 1 of the present disclosure will be described with reference to  FIG. 1 . 
     As illustrated in  FIG. 1 , a liquid ejecting device  1 A of the present example is provided with a first printing unit  17  capable of forming an image on a first surface Ma of a medium M, and a second printing unit  18  capable of forming an image on a second surface Mb on an opposite side of the medium M from the first surface Ma. The first printing unit  17  and the second printing unit  18  are both provided with a carriage  7  that includes a head  8  as an ejecting unit capable of ejecting liquid, and a transport device  6  that includes a driven roller  3 , a driving roller  4 , and a transporting belt  5  and is capable of transporting the medium M in a transport direction A. After the image is formed on the first surface Ma by the first printing unit  17 , the first surface Ma and the second surface Mb of the medium M are inverted by an inversion roller  10 , the medium M is transported to the second printing unit  18 , and the image is formed on the second surface Mb by the second printing unit  18 . 
     The first printing unit  17  is provided with a setting unit  2  that sets the roll-type medium M. Further, the first printing unit  17  is provided with a transport device  6 A capable of transporting the medium M, which has been fed out from the setting unit  2 , in a transport direction A, by rotating the roll-type medium M in a rotation direction C 1 . The transport device  6 A is provided with a driven roller  3 A positioned upstream in the transport direction A, a driving roller  4 A positioned downstream in the transport direction A, and a transporting belt  5 A that is an endless belt stretched across the driven roller  3 A and the driving roller  4 A. The medium M is supported on a support surface F, which is an outer surface of the transporting belt  5 A, and is transported. Note that an imaging unit  16 , which captures an image of the second surface Mb of the medium M, is provided between the setting unit  2  and the transport device  6 A. 
     Here, the transporting belt  5 A is an adhesive belt coated with an adhesive on the support surface F. As illustrated in  FIG. 1 , the medium M is supported and transported by the transporting belt  5 A in a state in which the medium M is adhered to the support surface F coated with the adhesive. In other words, the transporting belt  5 A is a support portion for the medium M. A support region over which the transporting belt  5 A supports the medium M is an upper-side region of the transporting belt  5 A that is stretched across the driven roller  3 A and the driving roller  4 A. Further, the driving roller  4 A is a roller that rotates as a result of a driving force of a transport motor  28  to be described later with reference to  FIG. 4 , and the driven roller  3 A is a roller that rotates as a result of being driven by the rotation of the transporting belt  5 A in accordance with the driving roller  4 A being rotated. 
     In addition, the first printing unit  17  is provided with a carriage  7 A and a head  8 A attached to the carriage  7 A. The head  8 A, which is an ejecting unit capable of ejecting liquid, functions as a printing unit capable of forming the image on the medium M transported in the transport direction A. The head  8 A is provided at a position facing the support region of the medium M on the transporting belt  5 , and can eject ink that contains a color material and forms the image on the medium M, and inhibitor that inhibits penetration of the color material into the medium M. The inhibitor is liquid capable of suppressing strike-through of the ink in the medium M by inhibiting the penetration of the color material in the ink into the medium M. The liquid ejecting device  1 A according to the present example is capable of printing the image by ejecting the ink from the head  8 A onto the transported medium M while reciprocating the carriage  7 A in a width direction B of the transporting belt  5  that intersects the transport direction A. As a result of being provided with the carriage  7 A configured in this manner, the liquid ejecting device  1 A according to the present example can form a desired image on the medium M by repeating the transport of the medium M in the transport direction A by a predetermined transport amount, and the ejection of the ink while moving the carriage  7 A in the width direction B in a state in which the medium M is stopped. Further, the carriage  7 A is provided with a gap changing unit  13  capable of adjusting a gap between the head  8 A and the support surface F at a position at which the head  8 A and the support surface F face each other. 
     Note that the liquid ejecting device  1 A according to the present example is a so-called serial printer that performs the printing by alternately repeating the transport of the medium M by the predetermined transport amount and the reciprocating movement of the carriage  7 . However, the liquid ejecting device  1  may be a so-called line printer, which uses a line head in which nozzles are formed in a line shape in the width direction B of the medium M, and which continuously performs printing while continuously transporting the medium M. 
     After the image is formed on the medium M by the ink being ejected from the head  8 A, the ink is dried by a drying unit  9 , and the medium M is sent to the second printing unit  18  via the inversion roller  10 . Here, the drying unit  9  of the present example is an infrared heater, but the configuration of the drying unit  9  is not particularly limited. In addition to the configuration in which electromagnetic waves are irradiated, as in the drying unit  9  of the present example, configurations in which heating is performed by an electrically heated wire, or by an air blowing fan, and the like are favorably used. 
     The second printing unit  18  is provided with a transport device  6 B. The transport device  6 B is provided with a driven roller  3 B having the same configuration as that of the driven roller  3 A, a driving roller  4 B having the same configuration as that of the driving roller  4 A, and a transporting belt  5 B having the same configuration as that of the transporting belt  5 A. In other words, the transport device  6 B has the same configuration as that of the transport device  6 A. Therefore, a detailed description of the transport device  6 B is omitted. Further, the second printing unit  18  is provided with a carriage  7 B. The carriage  7 B is provided with a head  8 B having the same configuration as that of the head  8 A. Further, the carriage  7 B is provided with the gap changing unit  13 , and the carriage  7 B has the same configuration as that of the carriage  7 A. Therefore, a detailed description of the carriage  7 B is omitted. 
     Then, the second printing unit  18  is provided with a winding unit  12  that takes up the medium M, on which the images have been formed by ejecting the ink from the head  8 A and the head  8 B, into a roll shape, by rotating the medium M in a rotation direction C 2 . Note that it goes without saying that the liquid ejecting device  1  may be provided with other structural members not mentioned above, such as a cleaning mechanism of the transporting belt  5 , a maintenance mechanism of the head  8 , and the like. 
     Here, a material for textile printing can be preferably used as the medium M. The term “material for textile printing” refers to a fabric, a garment, other clothing products and the like that are subject to printing. Fabrics include woven cloths, knit fabrics, non-woven cloths, and the like made of natural fibers such as cotton, silk, wool, and the like, chemical fibers such as nylon and the like, or composite fibers of natural fibers and chemical fibers. Further, the garments and other clothing products include sewn products, such as T-shirts, handkerchiefs, scarfs, towels, handbags, and fabric bags, furniture-related products such as curtains, sheets, and bed covers, as well as fabrics and the like before and after cutting that serve as pieces of cloth before sewing. 
     Note also that the medium M that can be used is not limited to the above-described material for textile printing. In addition to the material for textile printing described above, dedicated inkjet recording paper, such as plain paper, high quality paper, glossy paper, and the like, can be used. Further, for example, a plastic film whose surface has not been processed for inkjet printing, that is, on which an inkjet absorption layer is not formed, as well as a material in which plastic is coated on a substrate of paper or the like, and a material to which a plastic film has been adhered can also be used as the medium M. Such plastic materials include, but are not limited to, for example, polyvinyl chloride, polyethylene terephthalate, polycarbonate, polystyrene, polyurethane, polyethylene, and polypropylene. 
     Next, an example of the head  8  capable of being used in the liquid ejecting device  1 A of the present example will be described.  FIG. 2  is an example of the head  8  capable of being used in the liquid ejecting device  1 A of the present example. The head  8  illustrated in  FIG. 2  has a plurality of nozzle rows N 1  to N 6  in which nozzles that eject the liquid are arranged along the transport direction A. Specifically, the head  8  has the nozzle rows N 2  to N 5  that eject the ink that forms the image on the medium M, and the nozzle rows N 1  and N 6  that eject the inhibitor that inhibits the color material in the ink from penetrating to a surface on the opposite side, of the medium M, from the surface onto which the ink is ejected. By adopting the configuration in which the nozzle rows N 2  to N 5  are sandwiched by the nozzle rows N 1  and N 6 , the inhibitor can be ejected onto the medium M in advance of the ink in both the movement in the forward direction and the movement in the return direction, in the reciprocating movement of the carriage  7  in the width direction B. 
     Further,  FIG. 3  is an example of the head  8  capable of being used in the liquid ejecting device  1 A of the present example, and is a separate example from that of the head  8  illustrated in  FIG. 2 . In the head  8  illustrated in  FIG. 3 , nozzle rows N 7  and N 8  that eject the inhibitor are formed upstream in the transport direction A, and nozzle rows N 9  to N 12  that eject the ink are formed downstream in the transport direction A. Such a configuration allows the inhibitor to be ejected onto the medium M in advance of the ink. Note that, in the head  8  illustrated in  FIG. 3 , a configuration is adopted in which an inhibitor ejecting unit  19 A formed by the nozzle rows N 7  and N 8  that eject the inhibitor, and an ink ejecting unit  19 B formed by the nozzle rows N 9  to N 12  that eject the ink are provided on the same carriage  7 , but a configuration may be adopted in which the inhibitor ejecting unit  19 A and the ink ejecting unit  19 B are provided on the separate carriages  7 . In other words, any configuration may be adopted as long as the inhibitor ejecting unit  19 A is provided upstream of the ink ejecting unit  19 B in the transport direction A. 
     Here, for the ink, as long as the color material used to form the image on the medium M and a solvent of the color material are included therein, the ink can be used without particular limitations on the composition, physical properties, and the like thereof. However, when a pigment is used as the color material, the effect of inhibiting the strike-through of the ink by the inhibitor is higher than in a case where a dye is used as the color material. 
     It is also preferable that the inhibitor contain at least one of metal ions or saccharides. This is because, since the metal ions and the saccharides can favorably thicken the ink or coagulate the color material, and therefore, the penetration of the color material into the medium M can be favorably suppressed and the strike-through of the ink in the medium M can be favorably suppressed. Note that a multivalent metal can more favorably suppress the strike-through of the ink than a monovalent metal. Furthermore, by using chloride ions as the counterions of the metal, it is possible to suppress the influence of discoloration or the like of the medium M to a greater extent than when using nitrate ions or the like, for example. 
     Next, the electrical configuration of the liquid ejecting device  1 A of the present example will be described with reference to  FIG. 4 . 
     As illustrated in  FIG. 4 , the liquid ejecting device  1 A of the present example is provided with a control unit  20 . The control unit  20  is provided with a CPU  21  that performs control of the entire liquid ejecting device  1 . The CPU  21  is connected, via a system bus  22 , to a ROM  23  that stores various types of control programs and the like to be executed by the CPU  21 , and a RAM  24  that can temporarily store data. Here, a first printing mode execution program, which is used to form the image on the medium M by applying ink to the medium M without applying the inhibitor to the medium M, and a second printing mode execution program, which is used to form the image on the medium M by applying the inhibitor to the medium M and applying the ink to the medium M applied with the inhibitor, are stored in the ROM  23 . 
     Further, the CPU  21  is connected, via the system bus  22 , to a head driving unit  25  that drives the recording head  8 , that is, that causes the ink to be ejected. 
     Further, the CPU  21  is connected, via the system bus  22 , to a motor driving unit  26  that is connected to a carriage motor  27 , a transport motor  28 , a feeding motor  29 , a winding motor  30 , and a gap adjustment motor  31 . 
     Here, the carriage motor  27  is a motor that causes the carriage  7 , on which the head  8  is mounted, to reciprocate in the width direction B. In addition, the transport motor  28  is a motor that drives the driving roller  4 . Further, the feeding motor  29  is a rotating mechanism of the setting unit  2 , and is a motor that drives the setting unit  2  in order to feed the medium M onto the transporting belt  5 . Further, the winding motor  30  is a rotating mechanism of the winding unit  12 , and is a motor that drives the winding unit  12  in order to take up the medium M into the roll shape. Then, the gap adjustment motor  31  is a drive motor of the gap changing unit  13  capable of adjusting the gap between the head  8  and the support surface F by moving the carriage  7  in the vertical direction. 
     Additionally, the CPU  21  is connected, via the system bus  22 , to a drying unit driving unit  32  that drives the drying unit  9 . 
     Furthermore, the CPU  21  is connected, via the system bus  22 , to an input-output unit  33  that is connected to the imaging unit  16 , an operating panel  14  of the liquid ejecting device  1 , and a PC  34  that is used to perform reception and transmission of data, such as image data and the like, and signals. 
     Next, an example of a liquid ejecting method performed using the liquid ejecting device  1 A of the present example will be described using a flowchart in  FIG. 5 . 
     In the liquid ejecting method of the present example, first, at step S 110 , a user sets the medium M on the liquid ejecting device  1 A by setting the medium M on the setting unit  2 , and arranging the medium M on the liquid ejecting device  1 A so that the image can be formed on the medium M. 
     Next, at step S 120 , the user sets the printing mode using the operating panel  14 , the PC  34 , or the like. Specifically, the user selects whether to execute the first printing mode or the second printing mode. Note that, when the second printing mode is selected to be executed, it is also selected whether to perform a single-sided printing mode in which printing is performed on the first surface Ma only of the medium M, or a double-sided printing mode in which printing is performed on both the first surface Ma and the second surface Mb. 
     Then, at step S 130 , the control unit  20  determines whether the first printing mode is selected or the second printing mode is selected. When it is determined that the first printing mode is selected, the processing advances to step S 140 , and when it is determined that the second printing mode is selected, the processing advances to step S 180 . 
     At step S 140 , the imaging unit  16  captures an image of the second surface Mb of the medium M, that is, a back surface that is on the opposite side from a top surface when the first surface Ma on which the image is formed by the head  8 A is the top surface. 
     Then, at step S 150 , the control unit  20  determines, from imaging data of the image capturing unit  16 , whether or not an image is formed on the second surface Mb. When it is determined that the image is formed on the second surface Mb, the processing advances to step S 160 , and when it is determined that no image is formed on the second surface Mb, the processing advances to step S 180 . 
     At step S 160 , a warning operation is performed to alert the user that strike-through of the ink may occur. Specifically, for example, it is displayed on the operating panel  14  that the first printing mode is selected. This is because, since, in the first printing mode, the image is formed on the medium M by applying the ink to the medium M without applying the inhibitor to the medium M, depending on the type of the medium M used or the like, there is a risk that there may be strike-through of the ink, and if there is the strike-through of the ink, there is a risk that the quality of the image formed on the second surface Mb may deteriorate. Note that in the present example, an example is described in which a desired display is made on the operating panel  14  as the warning operation, but other warning operations may be performed, such as issuing a warning sound or warning message using voice or the like. 
     After performing the warning operation at step S 160 , the processing advances to step S 170 , where the user is prompted to choose whether or not to reset the printing mode. When the user chooses to reset the printing mode, the processing returns to step S 120  and causes the printing mode to be reset, and when the user chooses not to reset the printing mode, the processing advances to step S 180 . 
     At step S 180 , the transport of the medium M is started as a result of control by the control unit  20 , and the processing advances to step S 190 . 
     At step S 190 , a liquid ejecting operation is performed. Specifically, as a result of control by the control unit  20 , by repeating the transport of the medium M using the transport device  6 A and the transport device  6 B, and the ejecting of the ink, or the ink and the inhibitor, from the head  8 A and the head  8 B while causing the carriage  7 A and the carriage  7 B to reciprocate, the image is formed on the medium M. Here, when the first printing mode is selected, only the ink is ejected from the head  8 A and the head  8 B, and when the second printing mode is selected, the ink and the inhibitor are ejected from the head  8 A and the head  8 B. Note that, by control of the control unit  20 , an amount of ink applied per unit area when the second printing mode is selected is adjusted to be less than an amount of ink applied per unit area when the first printing mode is selected. Here, “the amount of ink applied per unit area when the second printing mode is selected is less than the amount of ink applied per unit area when the first printing mode is selected” means that the amount of ink applied per unit area in the second printing mode is less than the amount of ink applied per unit area in the first printing mode when forming the same image. The smaller the amount of ink applied per unit area, the less likely the strike-through of the ink in the medium M. Thus, in the second printing mode, the strike-through of the ink in the medium M is suppressed by reducing the amount of ink applied per unit area. 
     Note that at step S 190 , when the double-sided printing mode is selected at step S 120 , the first surface Ma is printed by the first printing unit  17 , and the second surface Mb is printed by the second printing unit  18 . On the other hand, when the single-sided printing mode is selected at step S 120 , the first surface Ma is printed by the first printing unit  17 , and only the transport and taking up of the medium M is performed at the second printing unit  18  without the printing being performed thereby. 
     It is then determined at step S 200  whether all of the printing of the image is complete, and, when it is determined that the printing is complete, the liquid ejecting method of the present example is ended. When it is determined that the printing is not complete, the processing returns to step S 180  and repeats the processing from step S 180  to step S 200 . 
     As described above, the liquid ejecting method of the present example is a liquid ejecting method for a liquid ejecting device  1  that is provided with the head  8  configured to be capable of ejecting liquid, that is, being capable of ejecting, as the liquid, the ink that contains the color material and forms the image on the medium M, and the inhibitor that inhibits the penetration of the color material into the medium M. Further, it is possible to select between the first printing mode in which the image is formed on the medium M by applying the ink to the medium M without applying the inhibitor to the medium M, and the second printing mode in which the image is formed on the medium M by applying the inhibitor to the medium M and applying the ink to the medium M applied with the inhibitor. At this time, the amount of ink applied per unit area in the second printing mode is less than the amount of ink applied per unit area in the first printing mode. 
     With respect to the above description from the point of view of a liquid ejecting device, the liquid ejecting device  1 A of the present example is provided with the head  8  capable of ejecting the liquid, and the control unit  20  controls the application of the liquid onto the medium M by causing the liquid to be ejected from the head  8 . Here, as the liquid, the head  8  is configured to be capable of ejecting the ink that contains the color material and forms the image on the medium M, and the inhibitor that inhibits the penetration of the color material into the medium M. Further, the control unit  20  is configured to select the first printing mode in which the control unit  20  forms the image on the medium M by applying the ink to the medium M without applying the inhibitor to the medium M, and the second printing mode in which the control unit  20  forms the image on the medium M by applying the inhibitor to the medium M and applying the ink to the medium M applied with the inhibitor. Further, the control unit  20  can cause the amount of ink applied per unit area in the second printing mode to be less than the amount of ink applied per unit area in the first printing mode. 
     In this way, the liquid ejecting method of the present example, and the liquid ejecting device  1 A of the present example cause the amount of ink applied per unit area in the second printing mode, in which the image is formed on the medium M by applying the ink to the medium M applied with the inhibitor, to be smaller than the amount of ink applied per unit area in the first printing mode, in which the image is formed on the medium M by applying the ink to the medium M without applying the inhibitor. Thus, the amount of ink applied per unit area in the second printing mode can be reduced, and by reducing the amount of ink applied, the strike-through of the ink in the medium M can be suppressed even when the medium M or ink that is susceptible to strike-through is used, for example. 
     Further, as described above, the liquid ejecting device  1 A of the present example is provided with the imaging unit  16  that captures the image of the second surface Mb, that is, the back surface, which is the surface on the opposite side from the top surface, when the first surface Ma, that is, the surface of the medium M facing the head  8 , is the top surface, and with the operating panel  14  as the warning unit capable of performing the warning operation as a result of control by the control unit  20 . Then, by performing the processing at step S 160 , the control unit  20  determines whether the image is formed on the back surface, based on the imaging data captured by the image capturing unit  16 . When it is determined that the image is formed on the back surface when the first printing mode is selected, the control unit  20  can cause the warning unit to perform the warning operation. Thus, when forming the image on the top surface of the medium M on which the image is formed on the back surface, the liquid ejecting device  1 A of the present example can reduce a possibility of deterioration of the quality of the image formed on the back surface by the strike-through of the ink ejected onto the top surface as a result of mistakenly selecting the first printing mode. 
     Further, as described above, the liquid ejecting device  1 A of the present example is provided with the support surface F that supports the medium M at the position facing the head  8 , and with the gap changing unit  13  that changes the gap between the head  8  and the support surface F. Then, the control unit  20  is capable of changing the amount of inhibitor applied per unit area in the second printing mode, on the basis of the gap. In general, the thin medium M is susceptible to the strike-through, and the thick medium M is not so susceptible to the strike-through, but the liquid ejecting device  1 A of the present example changes the amount of inhibitor applied per unit area in the second printing mode, on the basis of the gap between the head  8  and the support surface F that corresponds to the thickness of the medium M, and thus, the strike-through of the ink can be suppressed in accordance with the thickness of the medium M. For example, preferably, the amount of inhibitor applied per unit area is reduced as the gap between the head  8  and the support surface F increases, and the amount of inhibitor applied per unit area is increased as the gap between the head  8  and the support surface F narrows. The reason for this is that, when the gap between the head  8  and the support face F is large, this means that the medium M being used is thick, and it can be assumed that the strike-through of the ink does not easily occur. Thus, the amount of inhibitor applied per unit area may be reduced. On the other hand, when the gap between the head  8  and the support surface F is narrow, this means that the medium M being used is thin, and it can be assumed that the strike-through of the ink occurs easily. Thus, the amount of inhibitor applied per unit area is preferably increased. 
     In the liquid ejecting device  1 A of the present example, as the second printing mode, the control unit  20  can perform the single-sided printing mode in which the control unit  20  controls the head  8 A, applies the inhibitor to the first surface Ma of the medium M, forms the image on the first surface Ma by applying the ink to the first surface Ma applied with the inhibitor, and ends the printing. Further, in the liquid ejecting device  1 A of the present example, as the second printing mode, the control unit  20  can perform the double-sided printing mode in which the control unit  20  controls the head  8 A, applies the inhibitor to the first surface Ma, forms the image on the first surface Ma by applying the ink to the first surface Ma applied with the inhibitor, and subsequently controls the head  8 B, applies the inhibitor to the second surface Mb that is on an opposite side of the medium M from the first surface Ma, and forms the image on the second surface by applying the ink to the second surface applied with the inhibitor. In other words, the liquid ejecting device  1 A of the present example is able to selectively execute the single-sided printing mode and the double-sided printing mode. Thus, through the single-sided printing mode, the liquid ejecting device  1 A is able, while making the most of a basic condition of one surface of the medium M, to form the image on the other surface, and through the double-sided printing mode, is able to suppress the strike-through of the ink and form the images on both surfaces of the medium M. Here, the “basic condition” of the medium M refers to a state of the surface at a time at which the medium M is set on the setting unit  2 . A specific pattern of the “basic condition” can be assumed to be a blank state, or a state in which a design has been applied by a method other than the liquid ejecting device  1 A. The design applied by a method other than the liquid ejecting device  1 A can be assumed to be, for example, a pattern formed by weaving, a pattern formed by writing by hand, a pattern formed by screen printing, a pattern formed by another printer, and the like. Note that when the single-sided printing mode is selected, in the printing unit  18 , the carriage  7 B and the head  8 B are not driven, and only the transport device  6 B and the winding unit  12  are driven. 
     In other words, as the head  8 , the liquid ejecting device  1 A of the present example includes the head  8 A as a first ejecting unit capable of ejecting the liquid onto the first surface Ma, and the head  8 B as a second ejecting unit capable of ejecting the liquid onto the second surface Mb. Then, in the double-sided printing mode, the control unit  20  can perform control to form the image on the first surface Ma by ejecting the liquid from the head  8 A, and subsequently form the image on the second surface Mb by ejecting the liquid from the head  8 B. Thus, the liquid ejecting device  1 A of the present example can form the images on both surfaces of the medium M while favorably suppressing the strike-through of the ink, using the two heads  8 , that is, the head  8 A and the head  8 B. 
     In this way, the liquid ejecting device  1 A of the present example includes the two heads, that is, the head  8 A and the head  8 B, as the head  8 . However, a configuration may be adopted in which a single head is used as the head  8 . Below, Example 2 is described of a configuration including the single head as the head  8 . 
     Example 2 (FIG.  6 ) 
       FIG. 6  is a schematic side view illustrating a liquid ejecting device  1 B of the present example, and is a diagram corresponding to  FIG. 1  illustrating the liquid ejecting device  1 A of Example 1. Note that the same structural members as those in Example 1 described above are denoted by the same reference numerals, and a detailed description thereof will be omitted. 
     As illustrated in  FIG. 6 , the liquid ejecting device  1 B of the present example is provided with rotating shafts  15 A and  15 B that are rotatable in the rotation direction C 1  and that sandwich the transport device  6 . The rotation shafts  15 A and  15 B also serve as the setting unit  2  and the winding unit  12 , respectively. The liquid ejecting device  1 B of the present example first rotates the rotating shaft  15 A in the rotation direction C 1 , and feeds the medium M from the rotating shaft  15 A to the transport device  6 . Then, by driving the transport device  6  so that the driving roller  4  rotates in the rotation direction C 1 , the liquid ejecting device  1 B transports the medium M in a direction A 1  of the transport direction A, and uses the rotating shaft  15 B to take up the medium M on which the image has been formed on the first surface Ma by ejecting the liquid from the head  8 . Then, the liquid ejecting device  1 B rotates the medium M taken up by the rotation shaft  15 B in the rotation direction C 1  so that the second surface Mb faces the head  8 , and feeds the medium M from the rotating shaft  15 B to the transport device  6 . By driving the transport device  6  so that the driving roller  4  rotates in the rotation direction C 2 , the liquid ejecting device  1 B transports the medium M in a direction A 2  of the transport direction A, and uses the rotating shaft  15 A to take up the medium M on which the image has been formed on the second surface Mb by ejecting the liquid from the head  8 . According to such a configuration, the rotating shaft  15 A and the rotating shaft  15 B form an inversion mechanism  11  that allows the first surface Ma and the second surface Mb to be inverted and transported. 
     As described above, the liquid ejecting device  1  of the present example is provided with the inversion mechanism  11  for the medium M. Then, in the double-sided printing mode, after forming the image on the first surface Ma by ejecting the liquid from the head  8 , the control unit  20  controls the inversion mechanism  11  and inverts the medium M, and can perform control to form the image on the second surface Mb by ejecting the liquid from the head  8 . In other words, the liquid ejecting device  1  of the present example has a simple configuration provided with the single ejecting unit, and can also form the images on both surfaces of the medium M while suppressing the strike-through of the ink. 
     Note that the present disclosure is not limited to the above-described examples, and many variations are possible within the scope of the disclosure as described in the appended claims. It goes without saying that such variations also fall within the scope of the present disclosure.