Patent Publication Number: US-2023137201-A1

Title: Inkjet printer, printing system, and method for producing printed matter

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This patent application is based on and claims priority pursuant to 35 U.S.C. § 119(a) to Japanese Patent Application No. 2021-177881, filed on Oct. 29, 2021, in the Japan Patent Office, the entire disclosure of which is hereby incorporated by reference herein. 
     BACKGROUND 
     Technical Field 
     The present disclosure relates to an inkjet printer, a printing system, and a method for producing a printed matter. 
     Related Art 
     A technique has been known in which ink applied onto a recording medium using an inkjet printer is used as an adhesive member to adhere foil to the recording medium to thus transfer the foil. 
     Furthermore, a configuration including: a color ink layer including an image portion; an adhesive layer provided on the image portion in a stacked manner; and a foil body provided on the adhesive layer and stuck to the adhesive layer in a stacked manner has been disclosed. 
     SUMMARY 
     In an embodiment of the present disclosure, there is provided an inkjet printer for forming, on a base, an image layer and an adhesive layer on which foil is to be formed. The inkjet printer includes a first head, a second head, and processing circuitry. The first head discharges an ink for the image layer. The second head discharges inks for the adhesive layer including a first ink and a second ink. The second ink has a lower wet spreadability than a wet spreadability of the first ink. The processing circuitry controls the second head to form an image area included in the adhesive layer with the second ink in a case where a width of the image area is less than a threshold, and form the image area with the first ink in a case where the width of the image area is not less than the threshold. 
     In another embodiment of the present disclosure, there is provided a method for producing a printed matter with an inkjet printer to form, on a base, an image layer and an adhesive layer on which foil is to be formed. The method includes: discharging an ink for the image layer from a first head of the inkjet printer; discharging, from a second head, inks for the adhesive layer including a first ink and a second ink having a wet spreadability lower than a wet spreadability of the first ink; and controlling the second head to form an image area included in the adhesive layer with the second ink in a case where a width of the image area is less than a threshold, and form the image area with the first ink in a case where the width of the image area is not less than the threshold. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a cross-sectional view of a first configuration example of a printed matter according to an embodiment; 
         FIG.  2    is a cross-sectional view illustrating a second configuration example of a printed matter according to an embodiment; 
         FIG.  3    is a cross-sectional view of a configuration example of foil on a printed matter according to an embodiment; 
         FIG.  4    is a block diagram illustrating a general configuration of a printing system according to an embodiment; 
         FIG.  5    is a diagram illustrating a configuration of an inkjet printer according to an embodiment; 
         FIG.  6    is a diagram illustrating a configuration of a foil transfer apparatus according to an embodiment; 
         FIG.  7    is a diagram illustrating a configuration of a carriage according to an embodiment; 
         FIG.  8    is a block diagram illustrating a functional configuration of a controller according to an embodiment; 
         FIG.  9    is a flowchart of an example of operation of the inkjet printer, according to an embodiment; 
         FIG.  10    is a diagram illustrating a contact angle between a base and ink; 
         FIG.  11    is a diagram illustrating wet spreadability of inks; 
         FIG.  12    is a cross-sectional view of a printed matter according to an embodiment; and 
         FIG.  13    is a cross-sectional view of a printed matter according to a comparative example. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     Hereinafter, embodiments of the present disclosure are described in detail with reference to the accompanying drawings. In the drawings, like reference signs denote like elements, and redundant description may be omitted where appropriate. 
     Further, the embodiments described below exemplify an inkjet printer, a printing system, and a method for producing a printed matter for embodying the technical idea of the present disclosure, and the present disclosure is not limited to the embodiments described below. For example, the dimensions, materials, and shapes of components and the relative positions of the arranged components are given by way of example in the following description, and the scope of the present disclosure is not limited thereto unless particularly specified. The sizes, positional relations, and the like of components illustrated in the drawings may be exaggerated for clarity of description. 
     It is assumed that printing, image formation, word printing, and recording in the terms of the embodiments are synonyms. 
     Hereinafter, a description is given of an embodiment of the present disclosure. 
     Configuration Example of Printed Matter 
     A configuration of a printed matter  1  according to an embodiment will be described with reference to  FIGS.  1  to  3   .  FIGS.  1  and  2    are cross-sectional views illustrating configurations of printed matters.  FIG.  1    illustrates a printed matter  1  according to a first example.  FIG.  2    illustrates a printed matter  1   a  according to a second example.  FIG.  3    is a cross-sectional view illustrating a configuration of foil  13  on the printed matter  1  or  1   a.    
     As illustrated in  FIG.  1   , the printed matter  1  includes a base  10 , an image layer  11 , and an adhesive layer  12 . The printed matter  1  also includes the foil  13  on the adhesive layer  12 . 
     The base  10  is a plate-like or sheet-like member that has transmittance with respect to visible light, and includes a resin material, such as acrylic, polyvinyl chloride, or polycarbonate, glass, or the like. The visible light is, for example, light having a wavelength of about 380 nm to about 780 nm. 
     The image included in the image layer  11  is any image including an image of a character, a landscape, an animal, or the like. The image layer  11  is formed by printing on one of surfaces of the base  10 . In the present embodiment, the image layer  11  is formed with ink discharged from an inkjet printer. The inkjet printer will be separately described in detail with reference to  FIG.  5   . 
     The adhesive layer  12  is a layer that serves as an adhesive member for transferring the foil  13 . Foil can be transferred onto the adhesive layer  12 . In the printed matter  1 , the adhesive layer  12  is formed on the same surface of the base  10  as the surface on which the image layer  11  is formed. In the present embodiment, the adhesive layer  12  is formed with ultraviolet curable ink discharged from the inkjet printer. 
     The foil  13  is formed on the adhesive layer  12  by a foil transfer apparatus to enhance the glossy impression of the printed matter  1 . The foil transfer apparatus will be separately described in detail with reference to  FIG.  8   . 
     The distance H illustrated in  FIG.  1    represents a distance corresponding to the thickness of the base  10 . The non-glossy base  10  is used to increase the contrast with the glossy impression of the foil  13  to emphasize the gloss of the foil  13 . 
     On the other hand, as illustrated in  FIG.  2   , in the printed matter  1   a , the adhesive layer  12  is formed on a surface of the base  10  opposite to the surface on which the image layer  11  is formed. The distance Ha illustrated in  FIG.  2    represents the distance between the image layer  11  and the foil  13  on the adhesive layer  12 . In the printed matter  1   a , a three-dimensional effect can be obtained by appropriately selecting the distance Ha. 
     The configuration of the printed matter  1   a  is similar to the configuration of the printed matter  1  except for the surface of the base  10  on which the adhesive layer  12  is formed, and thus redundant description will be omitted. Hereinafter, the printed matter  1  will be described as a representative printed matter, but the printed matter  1   a  is similar. 
     As illustrated in  FIG.  3   , the foil  13  mainly includes three layers of a coloring layer  133 , a deposited layer  134 , and a foil adhesive layer  135 . Before being transferred to the base  10 , the foil  13  is laminated and held on a base film  131  with a release layer  132  between the foil  13  and the base film  131 . 
     The base film  131  functions as a base for holding the release layer  132 , the coloring layer  133 , the deposited layer  134 , and the foil adhesive layer  135 . 
     The release layer  132  is a layer for making it easy to peel the coloring layer  133 , the deposited layer  134 , and the foil adhesive layer  135  off the base film  131  at a time of the transfer to the printed matter  1 . 
     The coloring layer  133  is a layer that colors the foil  13 . For example, the coloring layer  133  is a yellow layer for the foil  13  that is golden. 
     The deposited layer  134  is a metal layer for expressing glossy impression. 
     The foil adhesive layer  135  is a layer for the transfer to the printed matter  1  as a transfer target object. 
     In the present embodiment, the configuration of the foil  13  before transfer to the base  10  is a roll-like configuration in which the base film  131  holding the foil  13  is wound around a paper tube. However, this configuration is not limitative, and a sheet-like configuration, for example, may be possible. 
     Configuration Example of Printing System 
       FIG.  4    is a block diagram illustrating a general configuration of a printing system  300  according to the present embodiment. The printing system  300  includes an inkjet printer  100  and a foil transfer apparatus  200 . 
     The inkjet printer  100  forms the image layer  11  and the adhesive layer  12  on the base  10  on the basis of image data. The inkjet printer  100  discharges ultraviolet curable coloring ink to print any image on the base  10  to thus form the image layer  11  on the base  10 . Furthermore, the inkjet printer  100  discharges ultraviolet curable clear ink or primer ink to print any image on the base  10  to thus form the adhesive layer  12  on the base  10 . 
     The foil transfer apparatus  200  transfers the foil  13  onto the adhesive layer  12 . 
     The coloring ink corresponds to ink for the image layer. The clear ink or the primer ink corresponds to ink for the adhesive layer. 
     In the present embodiment, the inkjet printer  100  discharges ultraviolet curable clear ink to form the adhesive layer  12 . 
     In the present embodiment, the printing system  300  discharges both the ink for forming the image layer  11  and the ink for forming the adhesive layer  12 , but the configuration is not limitative. The printing system  300  may include two or more inkjet printers, such as an inkjet printer that discharges ink for forming the image layer  11  and an inkjet printer that discharges ink for forming the adhesive layer  12 . Furthermore, the ink for forming the adhesive layer  12  may not be ultraviolet curable liquid. 
     Configuration Example of Inkjet Printer 
       FIG.  5    is a diagram illustrating an example of a configuration of the inkjet printer  100 , in which the inkjet printer  100  is viewed in a direction opposite to the direction in which the inkjet printer  100  discharges ink. 
     As illustrated in  FIG.  5   , the inkjet printer  100  includes a carriage  105 , heads  106 , a platen  122 , an encoder sensor  141 , and an ultraviolet (UV) emission light source  142 . The inkjet printer  100  also includes a main-scanning motor  108 , a gear  109 , a pressing roller  110 , a timing belt  111 , a guide rod  112 , an encoder sheet  140  (linear scale), a controller  150 , and an operation unit  160 . The inkjet printer  100  forms the image layer  11  and the adhesive layer  12  on the base  10  conveyed along a sub-scanning direction B by a registration roller or the like. 
     The carriage  105  includes heads  106   y  that discharge a yellow (Y) coloring ink, heads  106   m  that discharge a magenta (M) coloring ink, heads  106   c  that discharge a cyan (C) coloring ink, and heads  106   k  that discharge a black (K) coloring ink. The carriage  105  also includes heads  106   s  that discharge a clear ink for forming the adhesive layer  12 . The heads  106   y ,  106   m ,  106   c ,  106   k , and  106   s  are arranged along a main-scanning direction A. The heads  106   y ,  106   m ,  106   c ,  106   k , and  106   s  have the same configuration except that the inks to be discharged are different, and thus are collectively referred to as the heads  106  unless particularly distinguished. 
     Each of the heads  106   y , the heads  106   m , the heads  106   c , and the heads  106   k  is an example of a first head that discharges an ink for the image layer. The heads  106   s  are an example of a second head that discharges inks for the adhesive layer. 
     The inkjet printer  100  transmits the driving force of the main-scanning motor  108  to the carriage  105  through the gear  109 , the pressing roller  110 , and the timing belt  111  to reciprocate the carriage  105  in the main-scanning direction A along the guide rod  112 . In the inkjet printer  100 , the encoder sensor  141  provided in the carriage  105  reads the encoder sheet  140  provided along the moving direction of the carriage to detect the position of the moved carriage  105 . 
     In the inkjet printer  100 , the movement of the carriage  105  in the main-scanning direction A and the conveyance of the base  10  in the sub-scanning direction B are alternately performed to form the image layer  11  and the adhesive layer  12  on the base  10 . 
     The UV emission light source  142  irradiates the adhesive layer  12  on the base  10  with ultraviolet light. The UV emission light source  142  emits ultraviolet light to cure the inks discharged from the heads  106 . In the present embodiment, the UV emission light source  142  can irradiate, in addition to the adhesive layer  12 , the image layer  11  on the base  10  with ultraviolet light to cure the coloring inks constituting the image layer  11 . 
     The controller  150  can control the discharge of the ink by each of the plurality of heads  106 , the emission of ultraviolet light by the UV emission light source  142 , the movement of the carriage  105 , the conveyance of the base  10  by the registration roller, and the like. The controller  150  also acquires image data via a network or the like connected to the inkjet printer  100 . In the present embodiment, in particular, the controller  150  is an example of a control unit or circuitry that controls the heads  106   s  so that in a case where the width of an image area included in the adhesive layer  12  is less than a predetermined threshold, the image area is formed with a second ink, and in a case where the width of the image area is not less than the predetermined threshold, the image area is formed with a first ink. 
     The operation unit  160  is used, for example, by a user of the printing system  300  to give a printing instruction to the inkjet printer  100 , and by a user to specify whether the glossy impression of the foil  13  to be formed on the printed matter  1  is matte or glossy. The operation unit  160  includes a touch panel or the like that receives touch operation. 
     Configuration Example of Foil Transfer Apparatus 
       FIG.  6    is a diagram illustrating an example of a configuration of the foil transfer apparatus  200 . The foil transfer apparatus  200  includes a sheet feeding unit  201 , a pair of transfer rollers  202 , a winding unit  203 , a transfer roller  204 , a heater  205 , and a placement table  206 . 
     In the foil transfer apparatus  200 , the sheet feeding unit  201 , the pair of transfer rollers  202 , and the winding unit  203  are each rotated by a driving force of a motor or the like to convey the base  10 , as a transfer target body, on the placement table  206 , while the foil  13  is transferred to the base  10 . 
     The sheet feeding unit  201  is a supply mechanism that rotates a roller while winding, around the roller, the base film  131  holding the foil  13 , to supply the base film  131  toward the base  10 . 
     The pair of transfer rollers  202  includes two transfer rollers for transferring the foil  13  to the base  10 . One of the two transfer rollers included by the pair of transfer rollers  202  contains the heater  205 . The transfer rollers include an elastic material, such as rubber or sponge, at least on the surfaces. The pair of transfer rollers  202  holds the base  10  and the base film  131  between the two transfer rollers to apply a pressure to the base  10  and the base film  131 , to thus transfer the foil  13  held by the base film  131  to the base  10 . 
     The winding unit  203  is a winding mechanism that winds the base film  131  after the transfer of the foil  13  to the base  10 . 
     Configuration Example of Carriage 
       FIG.  7    is a diagram illustrating an example of a configuration of the carriage  105  of the inkjet printer  100 , in which the carriage  105  is viewed from the side of a direction in which the inkjet printer  100  discharges the inks. 
     As illustrated in  FIG.  7   , the carriage  105  includes the two heads  106   y , the two heads  106   m , the two heads  106   c , the three heads  106   k , two heads  106   s   1 , and one head  106   s   2 . The heads  106   s  include the two heads  106   s   1  and the one head  106   s   2 . 
     The two heads  106   y  are staggered along the sub-scanning direction B. Similarly, the two heads  106   m , the two heads  106   c , the three heads  106   k , and the two heads  106   s   1  are each staggered along the sub-scanning direction B. 
     The coloring inks discharged from the heads  106   y ,  106   m ,  106   c , and  106   k  are one type of inks having the same composition although the colors are different. That is, the yellow (Y) coloring ink used in the inkjet printer  100  is only one type of ink having predetermined wet spreadability. The same applies to the magenta (M) coloring ink, the cyan (C) coloring ink, and the black (K) coloring ink. 
     The two heads  106   s   1  each correspond to a third head that discharges a first ink. The one head  106   s   2  corresponds to a fourth head that discharges a second ink. The first ink discharged by each of the two heads  106   s   1  and the second ink discharged by the head  106   s   2  have different compositions, and are different types of inks. The second ink discharged by the head  106   s   2  has lower wet spreadability than the wet spreadability of the first ink discharged by each of the two heads  106   s   1 . 
     Functional Configuration Example of Controller 
       FIG.  8    is a block diagram illustrating an example of a functional configuration of the controller  150  of the inkjet printer  100 . The controller  150  controls the operation of the entire inkjet printer  100 . In the present embodiment, the controller  150  particularly includes a determination unit  151  and a discharge control unit  152 . 
     Each function of the determination unit  151  and the discharge control unit  152  can be implemented with an electric circuit, or part or all of these functions can be implemented with software (a central processing unit (CPU)). Alternatively, these functions of the controller  150  may be implemented with a plurality of circuits or a plurality of pieces of software. In addition to the functions of the determination unit  151  and the discharge control unit  152 , the controller  150  may include functions, such as a function of controlling both a mechanism for moving the carriage  105  in the main-scanning direction A and a mechanism for moving the base  10  in the sub-scanning direction B. 
     The determination unit  151  determines whether or not the width of an image area included in the adhesive layer  12  is less than a predetermined threshold. For example, image data Im as a source of an image to be formed on the base  10  is input into the determination unit  151  from an external apparatus, such as a client personal computer (PC), and the determination unit  151  performs the above determination on the image data Im. 
     The image area is a partial image (part of the image) included in the adhesive layer  12 , and includes a partial image, such as a thin-line portion including thin lines or a solid portion including a painted-out solid area. In the thin-line portion, the width of the image area corresponds to the gap between the thin lines included in the thin-line portion. In the solid portion, the width of the image area corresponds to the width of the solid portion. 
     For example, in a case where the gap between thin lines included in a thin-line portion is narrow, and is narrower than the width determined with the threshold, the determination unit  151  determines that the width of the image area is less than the threshold. For example, in a case where the gap between thin lines included in a thin-line portion is wider than the threshold, or in a case where the width of a solid portion is wider than the threshold, the determination unit  151  determines that the width of the image area is not less than the threshold. 
     In a case where the determination unit  151  determines that the width of the image area is less than the threshold, the discharge control unit  152  makes the head  106   s   2  discharge the second ink to form the image area with the second ink. In a case where the determination unit  151  determines that the width of the image area is not less than the threshold, the discharge control unit  152  makes the heads  106   s   1  discharge the first ink to form the image area with the first ink. The discharge control unit  152  can also make the heads  106   y ,  106   m ,  106   c , and  106   k  discharge the inks for the image layer to form the image layer  11 . 
     For example, in a case where the gap between thin lines included in a thin-line portion is narrow, the formation of the thin-line portion with an ink having large wet spreadability causes the ink to wetly spread, and the thin lines combine. As a result, in a case where the foil  13  is transferred to the adhesive layer  12  in the thin-line portion, the transfer unevenness of the foil  13  may occur, for example, the image in the thin-line portion cannot be visually recognized as the thin-line portion. In a case where the width of an image area, such as a thin-line portion, included in the adhesive layer  12  is less than the threshold, the controller  150  forms the image area with the second ink having wet spreadability smaller than the wet spreadability of the first ink to suppress the wet spreading of the ink and stably form a foil transfer image in a thin-line portion and the like. 
     Operation Example of Inkjet Printer 
       FIG.  9    is a flowchart illustrating an example of operation of the inkjet printer  100 . The inkjet printer  100  starts the operation in  FIG.  9   , for example, in a case where receiving an image formation start instruction due to the receipt of image data Im from a client PC, or in a case where receiving an image formation start instruction via the operation unit  160 . 
     First, in step S 91 , in the inkjet printer  100 , on the basis of the image data Im, the controller  150  determines whether or not an image layer  11  is to be formed. 
     In a case where in step S 91 , it is determined that an image layer  11  is to be formed (Yes in step S 91 ), in step S 92 , in the inkjet printer  100 , the discharge control unit  152  makes the heads  106   y ,  106   m ,  106   c , and  106   k  discharge the inks for the image layer to form the image layer  11  on a base  10 . 
     On the other hand, in a case where in step S 91 , it is determined that an image layer  11  is not to be formed (No in step S 91 ), in step S 93 , on the basis of the image data Im, the inkjet printer  100  determines whether or not the width of an image area included in an adhesive layer  12  is less than the threshold. 
     In a case where in step S 93 , it is determined that the width of an image area is less than the threshold (Yes in step S 93 ), in step S 94 , in the inkjet printer  100 , the controller  150  makes the head  106   s   2  discharge the second ink to form the adhesive layer  12  on the base  10  with the second ink. 
     On the other hand, in a case where in step S 93 , it is determined that the width of an image area is not less than the threshold (No in step S 93 ), in step S 95 , in the inkjet printer  100 , the controller  150  makes the heads  106   s   1  discharge the first ink to form the adhesive layer  12  on the base  10  with the first ink. 
     Next, in step S 96 , in the inkjet printer  100 , the controller  150  determines whether or not to end the image formation. For example, on the basis of the image data Im or according to an image formation end instruction via the operation unit  160 , the controller  150  determines whether or not to end the image formation. 
     In a case where in step S 96 , it is determined to end the image formation (Yes in step S 96 ), the inkjet printer  100  ends the operation. In a case where in step S 96 , it is determined not to end the image formation (No in step S 96 ), the inkjet printer  100  performs the operation after step S 91  again. 
     In this way, the inkjet printer  100  can form the image layer  11  and the adhesive layer  12  on the base  10 . 
     Action of Inkjet Printer 
     The action of the inkjet printer  100  will be described with reference to  FIGS.  10  to  13   .  FIG.  10    is a diagram for explaining a contact angle between a base  10  and ink.  FIG.  11    is a diagram for explaining wet spreadability of inks.  FIG.  12    is a cross-sectional view illustrating an example of a printed matter  1  according to an embodiment.  FIG.  13    is a cross-sectional view illustrating a printed matter  1 X according to a comparative example. In  FIGS.  12  and  13   , components having the same functions are denoted by the same reference numerals to simplify the description. 
     The wet spreadability of an ink can be generally expressed by a surface tension, and the following expression is established on the basis of Young&#39;s equation. 
       [Expression 1] 
       γ S =γ L ×cos θ+γ LS   (1)
 
     where γ S  represents the surface tension of the foundation of the adhesive layer  12 , γ L  represents the surface tension of an ink, γ LS  represents the interfacial tension between the foundation of the adhesive layer  12  and the ink, and θ represents the contact angle. The surface tensions γ S  and γ L , the interfacial tension γ LS , and the contact angle θ have the relationship illustrated in  FIG.  10   . 
     The wet spreadability of the ink is determined by the degree of the contact angle θ between the ink and the foundation of the adhesive layer  12 . Above Expression 1 can be transformed into following Expression 2. 
     
       
         
           
             [ 
             
               Expression 
               ⁢ 
                   
               2 
             
             ] 
           
         
       
       
         
           
             
               
                 
                   
                     cos 
                     ⁢ 
                     θ 
                   
                   = 
                   
                     
                       
                         γ 
                         LS 
                       
                       - 
                       
                         γ 
                         S 
                       
                     
                     
                       γ 
                       L 
                     
                   
                 
               
               
                 
                   ( 
                   2 
                   ) 
                 
               
             
           
         
       
     
     As can be seen from above Expression 2, when cos θ increases and approaches one, the contact angle approaches zero degrees, and as a result, the wet spreadability increases, and the adhesive layer  12  is formed widely. Conversely, when cos θ decreases and approaches zero, the contact angle increases and approaches 90 degrees and the wet spreadability decreases. When the wet spreadability decreases, the width of the ink having landed on the foundation of the adhesive layer  12  becomes substantially equal to the width of an ink droplet formed by a discharged ink. In  FIG.  11   , the inks K 1 , K 2 , and K 3  have higher wet spreadability in this order. 
     When the surface tension γ L  of the ink forming the adhesive layer  12  is increased, cos θ approaches zero, the contact angle θ increases, and wet spreading of the ink on the foundation (the base  10  in  FIG.  11   ) is suppressed. Therefore, when the width of an image area included in the adhesive layer  12  is small, an ink whose cos θ is close to zero may be used. 
     In the present embodiment, the inkjet printer  100  determines in advance the relationship between the threshold of the width of an image area included in the adhesive layer  12  and cos θ in the ink. In a case where the width of an image area is less than the threshold, the inkjet printer  100  forms the image area using the second ink whose cos θ is closer to zero than the first ink. Thus, the inkjet printer  100  forms a visually recognizable image area having a narrow width, and suppresses transfer unevenness of the foil  13 . 
     In the printed matter  1 X according to a comparative example illustrated in  FIG.  13   , an adhesive layer  12 X includes solid portions  121 X and  123 X and a thin-line portion  124 X. The adhesive layer  12 X is formed on an image layer  11  on a base  10 . Foil  13  is formed on the adhesive layer  12 X. In this case, the foundation of the adhesive layer  12 X corresponds to the image layer  11 . 
     For example, when one type of ink is used as an ink for the adhesive layer, the ink forming the thin-line portion  124 X in the adhesive layer  12 X wetly spreads on the image layer  11 , as illustrated in  FIG.  13   , and thus adjacent thin-line portions  124 X combine, and transfer unevenness of the foil  13  occurs in a foil transfer image on the thin-line portions  124 X. 
     On the other hand, in  FIG.  12   , an adhesive layer  12  includes solid portions  121  and  123  and a thin-line portion  124 . The adhesive layer  12  is formed on an image layer  11  on a base  10 . Foil  13  is formed on the adhesive layer  12 . In this case, the foundation of the adhesive layer  12  corresponds to the image layer  11 . 
     In the present embodiment, two types of inks are used as inks for the adhesive layer, the solid portions  121  and  123  are formed with the first ink, and the thin-line portion  124  is formed with the second ink having lower wet spreadability than the wet spreadability of the first ink. As a result, as illustrated in  FIG.  12   , wet spreading, on the image layer  11 , of the second ink forming the thin-line portion  124  in the adhesive layer  12  can be suppressed, and transfer unevenness of the foil  13  in a foil transfer image on the thin-line portion  124  can be suppressed. 
     Effects of Inkjet Printer 
     As described above, the inkjet printer  100  forms, on the base  10 , the image layer  11 , and the adhesive layer  12  on which the foil  13  can be formed. The inkjet printer  100  includes the heads  106   y ,  106   m ,  106   c , and  106   k  (first head) that discharge the inks for the image layer. As a second head, the inkjet printer  100  also includes the heads  106   s   1  (third head) that discharge the first ink as an ink for the adhesive layer, and the head  106   s   2  (fourth head) that discharges the second ink, as an ink for the adhesive layer, having lower wet spreadability than the wet spreadability of the first ink. The inkjet printer  100  also includes the controller  150  (control unit) that controls the heads  106   s  so that in a case where the width of an image area included in an adhesive layer  12  is less than the predetermined threshold, the image area is formed with the second ink, and in a case where the width of the image area is not less than the predetermined threshold, the image area is formed with the first ink. 
     In a case where the width of an image area, such as a thin-line portion  124 , in the adhesive layer  12  is less than the threshold, in the inkjet printer  100 , the controller  150  makes the second ink having lower wet spreadability than the wet spreadability of the first ink be discharged to form the image area. Thus, the inkjet printer  100  can suppress, for example, the combination of adjacent thin-line portions  124 . As described above, according to the present embodiment, it is possible to provide the inkjet printer  100  capable of suppressing the transfer unevenness of the foil  13 . 
     In the present embodiment, the configuration in which the inkjet printer  100  includes, as a second head, the three heads of the heads  106   s   1  and the head  106   s   2  has been exemplified, but the configuration is not limitative. In the inkjet printer  100 , one head may constitute the second head, and the first ink and the second ink may be discharged from the one head. In the inkjet printer  100 , three or more heads may constitute the second head, and the first ink and the second ink may be discharged from the three or more heads. 
     In the present embodiment, the inks for the adhesive layer are discharged onto the image layer  11  on the base  10 , and the type of the inks for the image layer is one type. Thus, the foil  13  transferred onto the adhesive layer  12  can be made conspicuous as compared with a case where the inks for the adhesive layer are discharged onto an image layer  11  formed with a plurality of types of inks for the image layer. 
     In the present embodiment, the first ink is an ink whose contact angle between the first ink and the image layer  11  (foundation of the adhesive layer) is less than 90 degrees, and the second ink is an ink whose contact angle between the second ink and the image layer  11  is 90 degrees or more. Thus, according to the present embodiment, it is possible to provide the inkjet printer  100  capable of suppressing, for example, the combination of adjacent thin-line portions  124 , and suppressing the transfer unevenness of the foil  13 . 
     In the present embodiment, the image layer  11  is exemplified as the foundation of the adhesive layer, but the foundation of the adhesive layer may be the base  10 . For example, in a case where the adhesive layer  12  and the image layer  11  are formed on the opposite sides, respectively, of the base  10 , the adhesive layer  12  is formed on a surface of the base  10  on the side opposite to the surface on which the image layer  11  is formed. In this case, the contact angle θ corresponds to the contact angle between the second ink and the base  10 . 
     Other Embodiments 
     Although several embodiments of the present disclosure have been described in detail above, the present disclosure is not limited to the specific embodiments, and various modifications and changes can be made within the scope of the gist of embodiments of the present disclosure described in the claims. 
     For example, a plurality of inkjet printers may be used, and the inkjet printer that forms the image layer  11  and the inkjet printer that forms the adhesive layer  12  may be different from each other. According to this configuration, in a case where the image layer  11  and the adhesive layer  12  are formed on mutually opposite surfaces of the base  10 , the step of reversing the base  10  can be omitted, and the printing time can be shortened. 
     The inkjet printer  100  and the foil transfer apparatus  200  can be configured as an integrated apparatus instead of a separate apparatus. 
     Embodiments also include a method for producing a printed matter. For example, the method for producing a printed matter is a method for producing a printed matter with an inkjet printer that forms, on a base, an image layer and an adhesive layer on which foil can be formed, in which in the inkjet printer, a first head discharges an ink for the image layer, a second head discharges inks for the adhesive layer including a first ink and a second ink having wet spreadability lower than wet spreadability of the first ink, and a control unit controls the second head so that in a case where a width of an image area included in the adhesive layer is less than a predetermined threshold, the image area is formed with the second ink, and in a case where the width of the image area is not less than the predetermined threshold, the image area is formed with the first ink. Such a method for producing a printed matter provides similar effects as the effects of the inkjet printer  100  described above. The method for producing a printed matter may be implemented with a circuit, such as a CPU or large-scale integration (LSI), an integrated circuit (IC) card, a single module, or the like. 
     All numbers, such as ordinal numbers and quantities, used in the description of the embodiments are exemplified to specifically describe the technology of the present disclosure, and the present disclosure is not limited to the exemplified numbers. In addition, the above-described connections among the components are examples for specifically describing the technology of the present disclosure, and connections for implementing functions of the present disclosure are not limited to the above-described examples. 
     Furthermore, the division into the blocks in the functional block diagrams is an example, and a plurality of blocks may be implemented as one block, one block may be divided into a plurality of blocks, or part of the function may be transferred to another block. In addition, functions of a plurality of blocks having similar functions may be processed in parallel or in a time division manner by single hardware or software. 
     In addition, each function of the above-described embodiments can be implemented by one or a plurality of processing circuits. Here, the “processing circuit” in the present specification includes a processor programmed to execute each function with software like a processor implemented by an electronic circuit, and a device, such as an application-specific integrated circuit (ASIC), a digital signal processor (DSP), a field-programmable gate array (FPGA), or a conventional circuit module, designed to execute each function described above.