Printer and adjustment method

Abstract

To perform appropriate printing of a three-dimensional medium.SOLUTION: A printer 10 printing a three-dimensional medium 50 includes an ink jet head 102, a main scanning driving part 16, and a control unit 30. During adjustment of the printer 10, the control unit 30 has the ink jet head 102 draw a first pattern and a second pattern. The first and second patterns are drawn at the same position in a main scanning direction of the medium 50 when a position of the ink jet head 102 relative to the medium 50 is a prescribed reference position. The ink jet head 102 draws the first pattern with a position of a nozzle array relative to the medium 50 at the first position, and draws the second pattern with a position of the nozzle array relative to the medium 50 at a second position.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a printing apparatus and an adjustment method. [Background technology]

[0002] Conventionally, there is known a printing device that performs printing on the outer surface of a cylindrical body by an inkjet method (see, for example, Patent Document 1). The printing device disclosed in Patent Document 1 mounts a cylindrical body that does not absorb ink on a mandrel that is rotatable about a central axis and is movable in the axial direction and in a direction perpendicular to the axial direction, and then sprays ultraviolet-curable ink of each color from each inkjet head of an inkjet head group composed of a plurality of nozzles that spray ink of each color onto the outer surface of the cylindrical body to perform a desired decorative print, irradiates the decorative print with ultraviolet light, and then irradiates the decorative print with ultraviolet light to cure it. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2010-143200 A Summary of the Invention [Problem to be solved by the invention]

[0004] When printing on a medium to be printed on using the inkjet method, ink is typically ejected from the inkjet head while the inkjet head is moved relative to a position on the medium that faces the inkjet head. In addition, ink droplets ejected from the inkjet head fly between the inkjet head and the medium to reach the medium. In this case, in order to print with high quality, it is desirable to eject ink from the inkjet head at a timing that matches the distance (head gap) between the inkjet head and the medium.

[0005] In addition, in this regard, when printing on a medium having a three-dimensional shape (three-dimensional medium) using the inkjet method, if there is a deviation in the position of the inkjet head relative to the medium, it may be difficult to perform high-quality printing. More specifically, when printing on a flat medium such as paper or film, even if there is a deviation in the position of the inkjet head relative to the medium, there is no change in the head gap. However, in the case of a three-dimensional medium, the head gap changes depending on the position of the medium. Therefore, if there is a deviation in the position of the inkjet head relative to the medium, there will also be a deviation in the head gap. As a result, for example, when performing color printing using a plurality of different colors of ink, there may be differences in the deviation of the landing position depending on the ink color, and the print quality may deteriorate. Therefore, in the past, there has been a demand for more appropriate printing on three-dimensional media. Therefore, an object of the present invention is to provide a printing device and an adjustment method that can solve the above problems. [Means for solving the problem]

[0006] The inventors of the present application have conceived of detecting the position of the inkjet head relative to the medium and adjusting it as necessary when printing on a three-dimensional medium using an inkjet method. As a method for doing so, they have conceived of making the inkjet head draw patterns that overlap on the medium when the relative position of the inkjet head is correct, and do not overlap when the relative position of the inkjet head is deviated from the correct position. Furthermore, through extensive research, the inventors of the present application have conceived of using, as such patterns, a first pattern drawn by a nozzle row (a nozzle row in an inkjet head) whose relative position with respect to the medium is at a first position, and a second pattern drawn by a nozzle whose relative position with respect to the medium is at a second position. With this configuration, for example, it is possible to detect the position of the inkjet head relative to the medium, and appropriately adjust the position of the inkjet head as necessary.

[0007] Furthermore, the inventor of the present application has further studied and found the features necessary to obtain such an effect, and has arrived at the present invention. In order to solve the above problems, the present invention is a printing device for printing on a three-dimensional medium, comprising an inkjet head having a nozzle row in which a plurality of nozzles are arranged at different positions in a predetermined nozzle row direction, a main scanning drive unit that causes the inkjet head to perform a main scanning operation of ejecting ink while moving in a main scanning direction that is preset relative to a position facing the nozzle row on the medium, and a control unit that controls the operation of the inkjet head and the main scanning drive unit, and when adjusting the printing device, the control unit causes the inkjet head to print a first pattern and a second pattern. The inkjet head is characterized in that the first pattern and the second pattern are patterns that are drawn at the same position in the main scanning direction of the medium when the position of the inkjet head relative to the medium is a predetermined reference position, and the inkjet head draws the first pattern by ink ejected from the nozzles in the nozzle row when the position of the nozzle row relative to the medium is at a first position, and draws the second pattern by ink ejected from the nozzles in the nozzle row when the position of the nozzle row relative to the medium is at a second position different from the first position.

[0008] In this configuration, for example, when the relative position of the inkjet head having the nozzle row is aligned with a reference position, the first pattern and the second pattern are drawn at the same position in the main scanning direction on the medium. Also, when the relative position of the inkjet head is deviated from the reference position, a deviation occurs in the positions (positions in the main scanning direction) where the first pattern and the second pattern are drawn on the medium. Therefore, with this configuration, for example, it is possible to properly detect whether the relative position of the inkjet head is aligned with the reference position. Also, this makes it possible to properly adjust the relative position of the inkjet head, for example, as necessary. Therefore, with this configuration, for example, it is possible to more appropriately print on a three-dimensional medium.

[0009] In this configuration, the position of the nozzle row relative to the medium (relative position of the nozzle row) can be considered to correspond to the position of the inkjet head relative to the medium. Regarding the relative position of the inkjet head, the reference position can be considered to correspond to a predetermined correct position. Furthermore, the first pattern and the second pattern being drawn at the same position in the main scanning direction can be considered to be drawn at substantially the same position with an accuracy according to the quality required for printing, for example. The first pattern and the second pattern being drawn at the same position in the main scanning direction can be considered to be overlapping with the second pattern in the main scanning direction, for example.

[0010] In this configuration, the medium is held by a holding member disposed at a position facing the inkjet head. In this case, the holding member includes a rotation mechanism that rotates the medium while holding the medium at a position facing the nozzle row. The main scanning drive unit rotates the medium using the rotation mechanism, for example, to move the inkjet head in the main scanning direction relative to the position on the medium facing the nozzle row. With this configuration, for example, when a three-dimensional medium is used, the inkjet head can be caused to perform a main scanning operation appropriately. This also makes it possible to appropriately print on a three-dimensional medium. For example, a cylindrical (cylindrical) medium can be suitably used as the medium held by the holding member. In this case, the cylindrical medium can be considered as an example of a medium having a rotating body shape. In addition, it is also possible for the holding member to hold a medium having a rotating body shape other than a cylindrical shape. In this case, it is also possible to use a medium having a conical or truncated conical shape, for example. Furthermore, when the medium is rotated by the holding member, the first pattern and the second pattern being drawn at the same position in the main scanning direction can also be thought of as, for example, the first pattern and the second pattern being drawn at the same position in the rotation direction.

[0011] In this configuration, the first pattern and the second pattern may be drawn using, for example, a plurality of nozzle rows of one inkjet head. In this case, the inkjet head has, for example, a plurality of nozzle rows whose positions in the main scanning direction are different from each other. These nozzle rows may be considered, for example, as a plurality of nozzle rows whose relative positions with respect to one another are known. The fact that the positions of the plurality of nozzle rows are different from each other in the main scanning direction may be considered, for example, as the positions of the plurality of nozzle rows in the inkjet head in the main scanning direction are different from each other when the inkjet head is in a position where it ejects ink onto a medium. More specifically, in this case, for example, the first pattern is drawn by ejecting ink from nozzles in a first nozzle row among the plurality of nozzle rows in one inkjet head. Then, the second pattern is drawn by ejecting ink from nozzles in a second nozzle row different from the first nozzle row. With this configuration, for example, the first pattern and the second pattern can be appropriately drawn using a plurality of nozzle rows. This also makes it possible to appropriately detect, for example, whether the position of the inkjet head having these nozzle rows is aligned with a reference position.

[0012] In addition, when an inkjet head having a plurality of nozzle rows is used and the above-mentioned holding member is used, it is possible to make the inkjet head draw the first pattern and the second pattern in a state where the relative position of the inkjet head with respect to the medium is fixed in a position where the first nozzle row and the second nozzle row are on opposite sides of the rotation axis on which the rotation mechanism rotates the medium, for example, with respect to the position in the main scanning direction. In this case, it is possible to align the center position of the first nozzle row and the second nozzle row in the inkjet head with the position of the rotation axis of the medium, for example, with respect to the position in the main scanning direction. In addition, the control unit of the printing device, for example, in this state, causes the nozzles in the first nozzle row and the nozzles in the second nozzle row to eject ink, thereby making the inkjet head draw the first pattern and the second pattern. With this configuration, for example, when the medium is rotated by the holding member, it is possible to make the plurality of nozzle rows of one inkjet head draw the first pattern and the second pattern appropriately.

[0013] In this configuration, for example, the first pattern and the second pattern may be patterns whose overlapping state changes according to the degree of positional deviation when the position of the inkjet head relative to the medium deviates from a reference position. With this configuration, for example, the relative position of the inkjet head can be adjusted more easily and appropriately. In this configuration, the printing device may include, for example, a plurality of inkjet heads. In this case, for example, in addition to the above-mentioned first pattern and second pattern, it is also possible to cause the inkjet head to draw a pattern for detecting the deviation of the distance between the inkjet heads. As such a pattern, for example, a pattern whose state changes according to the distance between the plurality of inkjet heads may be used. In this case, the control unit of the printing device further causes the plurality of inkjet heads to draw a pattern whose state changes according to the distance between the plurality of inkjet heads. In this case, the above-mentioned first pattern and second pattern may be considered as patterns for adjusting the deviation of the landing position that occurs between a plurality of nozzle rows whose relative positions are known, such as a plurality of nozzle rows in one inkjet head. In contrast, the above-described patterns for detecting deviations in the distance between inkjet heads can be considered as patterns for adjusting deviations in landing positions that occur between inkjet heads, for example.

[0014] Also, when a medium is held by a holding member and printing is performed while rotating the medium, it is possible to draw the first pattern and the second pattern with different rotation directions of the medium. In this case, the features of the present invention can be considered, for example, by focusing on the configuration of a printing device that prints on a three-dimensional medium held by a holding member. In this case, the present invention relates to, for example, a printing device that prints on a three-dimensional medium held by a holding member that holds a medium to be printed, the printing device including an inkjet head having a nozzle row in which a plurality of nozzles are arranged at different positions in a predetermined nozzle row direction, a main scanning drive unit that causes the inkjet head to perform a main scanning operation of ejecting ink while moving in a main scanning direction that is preset relative to a position on the medium facing the nozzle row, and a control unit that controls the operation of the inkjet head and the main scanning drive unit, the holding member includes a rotation mechanism that rotates the medium while holding the medium at a position facing the nozzle row, and the main scanning drive unit rotates the medium using the rotation mechanism to rotate the inkjet head in the main scanning direction relative to a position on the medium facing the nozzle row. During the adjustment of the printing device, the control unit causes the inkjet head to draw a first pattern and a second pattern, and the first pattern and the second pattern are patterns that are drawn at the same position in the main scanning direction of the medium when the position of the inkjet head relative to the medium is a predetermined reference position, and when the medium is rotated by the rotation mechanism in a first rotation direction, the inkjet head draws the first pattern with ink ejected from the nozzles in the nozzle row, and when the medium is rotated by the rotation mechanism in a second rotation direction opposite to the first rotation direction, the inkjet head draws the second pattern with ink ejected from the nozzles in the nozzle row. Even in this configuration, it is possible to appropriately detect, for example, whether the relative position of the inkjet head is aligned with the reference position. This also makes it possible to more appropriately print on a three-dimensional medium, for example.In addition, as a configuration of the present invention, it is also possible to use an adjustment method or the like having the same characteristics as described above. In this case, for example, the same effects as described above can be obtained. Effect of the Invention

[0015] According to the present invention, for example, printing can be performed more appropriately on a three-dimensional medium. [Brief description of the drawings]

[0016] [Figure 1] 1A is a diagram illustrating a printing device 10 according to an embodiment of the present invention. Fig. 1A shows an example of the configuration of the main part of the printing device 10. Fig. 1B shows an example of the configuration of a head unit 12. [Diagram 2] 2A and 2B are a cross-sectional view and a top view showing an example of the configuration of the holding jig 40 in a simplified manner. [Diagram 3] 3A is a diagram showing an example of the configuration of the holding jig 40. Fig. 3(a) is a cross-sectional view showing an example of a more specific configuration of the holding jig 40. Fig. 3(b) is a perspective view showing an example of the configuration of the ultraviolet irradiator 208 in the holding jig 40. [Figure 4] 4 is a diagram illustrating the target of adjustment to be made to the printing device 10. Fig. 4(a) shows an example of a correct state where no adjustment is required, and Fig. 4(b) shows an example of a state where adjustment is required. [Diagram 5] 5A is a diagram illustrating the patterns that are drawn by the printing device 10 during adjustment. Fig. 5A is a diagram illustrating the patterns 302a and b that are drawn by the inkjet head 102. Fig. 5B shows an example of the state of the patterns 302a and b that are drawn when there is no misalignment in the relative position of the inkjet head 102 with respect to the medium 50. [Figure 6] 6A and 6B are diagrams illustrating patterns that are drawn by the printing device 10 during adjustment. 6A and 6B show examples of the states of patterns 302a and 302b that are drawn when there is a deviation in the relative position of the inkjet head 102 with respect to the medium 50. [Figure 7]7(a) and 7(b) are diagrams illustrating adjustment of the distance between the inkjet heads 102. Figures 7(a) and 7(b) are diagrams illustrating problems that occur when the distance between the inkjet heads 102 is misaligned. Figure 7(c) shows an example of patterns 304a and 304b used when adjusting the distance between the inkjet heads 102. [Figure 8] 8A and 8B are diagrams illustrating modified examples of adjustment operations for the printing device 10. FIG. 8A and FIG. 8B show examples of adjustment operations. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a diagram illustrating a printing device 10 according to an embodiment of the present invention. Fig. 1(a) shows an example of the configuration of the main parts of the printing device 10. Except for the points described below, the printing device 10 and each part of the printing device 10 may have the same or similar features as a known printing device and each part thereof.

[0018] In this example, the printing device 10 is an inkjet printer that performs printing on a three-dimensional medium 50 held by a holding jig 40 using ultraviolet curable ink (UV ink). The ultraviolet curable ink can be considered to be, for example, ink that is fixed to the medium 50 by being cured by irradiation with ultraviolet rays. The medium 50 can be considered to be, for example, a workpiece that is a target of printing processing in the printing device 10. In this example, the holding jig 40 is an example of a holding member that holds the medium 50, and holds the medium 50 rotatably around a predetermined rotation axis at a position facing the inkjet head 102, and rotates the medium 50 according to the control of the printing device 10. In this case, the position facing the inkjet head 102 can be considered to be, for example, a position facing the nozzle row of the inkjet head 102. Holding the medium 50 at a position facing the inkjet head 102 can be considered to be, for example, holding the medium 50 at a position facing the inkjet head 102 when ink is discharged from the inkjet head 102 to the medium 50. In this embodiment, the holding jig 40 is equipped with an ultraviolet irradiator and irradiates ultraviolet light onto the outer surface of the medium 50. The configuration of the holding jig 40 will be described in more detail later.

[0019] In this example, the printing device 10 includes a head unit 12, a base unit 14, a main scanning drive unit 16, a sub-scanning drive unit 18, a sensor 20, a sensor moving means 22, and a control unit 30. The head unit 12 has an inkjet head that ejects ink onto a medium 50. The configuration of the head unit 12 will be described in more detail later. The base unit 14 is a table-like member that holds a holding jig 40 at a position facing the head unit 12. In this example, the base unit 14 holds the holding jig 40 so that the medium 50 held by the holding jig 40 and the inkjet head in the head unit 12 face each other by placing the holding jig 40 on the upper surface. The main scanning drive unit 16 is a drive unit that causes the inkjet head in the head unit 12 to perform a main scanning operation. The main scanning operation can be considered to be, for example, an operation of ejecting ink while moving relatively to the medium 50 in a preset main scanning direction (Y direction in the figure). In this example, the main scanning driver 16 rotates the medium 50 on the holding jig 40 in response to control from the controller 30, thereby moving the inkjet head relative to a position on the medium 50 that faces the nozzle row. In this case, the inkjet head can be considered to move in the main scanning direction relative to a position on the medium 50 where ink is ejected, for example, as the medium 50 rotates. In this case, the main scanning operation in this example can also be considered to be, for example, an operation of ejecting ink onto the rotating medium. The main scanning operation can also be considered to be, for example, an operation of ejecting ink onto the medium 50 while fixing the position of the inkjet head relative to the medium 50 in the sub-scanning direction.

[0020] The sub-scanning driver 18 is a driver that causes the inkjet head in the head unit 12 to perform a sub-scanning operation. The sub-scanning operation can be considered, for example, as an operation of moving relatively to the medium 50 in a sub-scanning direction (X direction in the figure) perpendicular to the main scanning direction. The sub-scanning operation can also be considered, for example, as a feed operation that changes the range of the medium facing the inkjet head by relative movement in the sub-scanning direction. In this example, the main scanning direction is an example of a predetermined first direction. The sub-scanning direction is an example of a second direction perpendicular to the first direction. The main scanning operation is an example of a first scan that ejects ink while moving in the first direction relative to each position on the medium 50. The sub-scanning operation is an example of a second scan that moves relatively to the medium 50 in the second direction.

[0021] The sensor 20 is a detection means used to detect the state of the holding jig 40. In this example, the sensor 20 is a photosensor that detects light such as ultraviolet light, and detects, for example, ultraviolet light leaking from an opening of the holding jig 40. With this configuration, for example, it is possible to properly detect whether the medium 50 or the like is properly installed on the holding jig 40. More specifically, in this case, for example, it is possible to detect the misalignment of the cover or the medium 50 by detecting the leakage of ultraviolet light caused by the misalignment of the cover or the medium 50 in the holding jig 40 using the sensor 20. In addition, it is also possible to detect, for example, the state of the gap generated between the cover of the holding jig 40 and the medium 50 based on the detection result of the sensor 20. The sensor moving means 22 is a means for moving the sensor 20 relative to the holding jig 40, and moves the sensor 20 to match the location where the sensor 20 performs detection. The control unit 30 is a part including, for example, a CPU of the printing device 10, and controls the operation of each part of the printing device 10 in accordance with a program such as firmware (FW) of the printing device 10.

[0022] Next, the configuration of the head unit 12 will be described in more detail. FIG. 1(b) shows an example of the configuration of the head unit 12. In this example, the head unit 12 has a plurality of inkjet heads 102 that eject ultraviolet curable ink. More specifically, in this example, the head unit 12 has four inkjet heads 102, as shown in the figure with reference numerals 102a to d for distinction. Among them, the inkjet heads 102a to c are aligned in the main scanning direction with their positions in the sub-scanning direction being the same. In addition, the inkjet head 102d is arranged with its position in the sub-scanning direction shifted from the inkjet heads 102a to c. In this case, regarding the configuration of the head unit 12, for example, it can be considered that at least some of the inkjet heads 102 in the head unit 12 are aligned in the main scanning direction with their positions in the sub-scanning direction being the same. In addition, regarding the configuration of the head unit 12, for example, it can be considered that some of the inkjet heads 102 are arranged with their positions in the sub-scanning direction shifted from the other inkjet heads 102.

[0023] Also, in the present embodiment, the inkjet head 102 has a plurality of nozzle rows 112 (two nozzle rows 112), as shown by assigning the reference numerals 112a and 112b to the inkjet head 102 with the reference numeral 102a in the drawing to distinguish them from one another. In this case, the nozzle rows 112 can be considered as, for example, a row in which a plurality of nozzles are arranged at different positions in a predetermined nozzle row direction. In this embodiment, the nozzle row direction is parallel to the sub-scanning direction. The positions of the plurality of nozzle rows 112 in the main scanning direction are different from one another. The fact that the positions of the plurality of nozzle rows 112 in the main scanning direction are different from one another can be considered as, for example, that the positions of the plurality of nozzle rows 112 in the inkjet head 102 in the main scanning direction are different from one another when the inkjet head 102 is in a position at which ink is ejected onto the medium 50. Also, in this embodiment, the plurality of nozzle rows 112 in the same inkjet head 102 can be considered as, for example, a plurality of nozzle rows 112 in which the relative positions of one with respect to the other are known. The inkjet head 102 ejects, for example, ink of a plurality of colors from a plurality of nozzle rows 112. More specifically, in this case, the inkjet head 102 ejects, for example, ink of a first color from a first nozzle row 112, and ejects ink of a second color different from the first color from a second nozzle row 112 different from the first nozzle row 112. Furthermore, the inkjet head 102 may eject ink of the same color from a plurality of nozzle rows 112 depending on the desired printing content, etc.

[0024] Here, in this example, the printing device 10 performs printing by a multi-pass method. In this case, the multi-pass method can be considered as, for example, a method in which the number of main scanning operations performed in a state where one position of the medium 50 faces the nozzle row is multiple. Furthermore, when printing is performed in the printing device 10 of this example, the control unit 30 moves the head unit 12 relatively to the medium 50, so that the inkjet heads 102 in the head unit 12 are moved in sequence to directly above the rotating medium 50 and face the medium 50. In addition, as a result, the control unit 30 causes the multiple inkjet heads 102 to eject ink onto the medium 50 in sequence. More specifically, in this case, the control unit 30 causes, for example, a first inkjet head 102 to eject ink onto the entire printing range on the side of the medium 50 in a state where the first inkjet head 102 and the medium 50 face each other. Furthermore, after causing the first inkjet head 102 to eject ink onto the medium 50, the control unit 30 causes a second inkjet head 102 different from the first inkjet head 102 to face the medium 50, and in this state, causes the inkjet head 102 to eject ink onto the side surface of the medium 50 in the same manner as described above. By repeating similar operations thereafter, the control unit 30 causes the multiple inkjet heads 102 in the head unit 12 to eject ink onto the medium 50. According to this example, for example, printing onto the medium 50 can be performed appropriately.

[0025] Next, the configuration of the holding jig 40 used in the printing device 10 of this example will be described in more detail. FIG. 2 and FIG. 3 show an example of the configuration of the holding jig 40. FIG. 2(a) and FIG. 2(b) are a cross-sectional view and a top view showing a simplified example of the configuration of the holding jig 40. FIG. 3(a) is a cross-sectional view showing a more specific example of the configuration of the holding jig 40. FIG. 3(b) is a perspective view showing an example of the configuration of the ultraviolet irradiator 208 in the holding jig 40. As described above, in this example, the holding jig 40 holds the medium 50 rotatably. In addition, the holding jig 40 irradiates the outer surface of the medium 50 with ultraviolet rays. In order to perform these operations, in this example, the holding jig 40 has a housing unit 202, a cover 204, a rotation mechanism 206, an ultraviolet irradiator 208, a light source holding unit 210, and a cover moving means 212.

[0026] The housing part 202 is a housing part of the holding jig 40 that constitutes the bottom and side surfaces of the holding jig 40, and houses the rotating mechanism 206, the ultraviolet irradiator 208, the light source holding part 210, and the like between the housing part 202 and the cover 204. The cover 204 is a member that covers the upper surface of the holding jig 40. The upper surface of the holding jig 40 can be considered to be, for example, the surface of the holding jig 40 that faces the inkjet head 102 (see FIG. 1). The cover 204 can be considered to be, for example, a member that covers at least the ultraviolet irradiator 208 from the upper surface side of the holding jig 40. In this example, the cover 204 has an opening 220 at a position facing the nozzle row of the inkjet head 102, and covers the upper surface of the holding jig 40 while facing the nozzle row and the medium 50 at the position of the opening 220. In this case, the opening 220 at a position facing the nozzle row can be considered to be, for example, that the opening 220 is provided at a position facing the nozzle row of one of the inkjet heads 102 when the inkjet head 102 is opposed to the medium 50 during printing. The opening 220 can also be considered to be, for example, an opening on the upper surface of the holding jig 40 so that ink ejected from the nozzle row of the inkjet head 102 reaches the medium 50.

[0027] In this example, the cover 204 has a base portion 222 and a magnet sheet 224. The base portion 222 is a plate-like portion constituting the base portion of the cover 204, and holds the magnet sheet 224 at a position between the inkjet head 102 and the medium 50. The magnet sheet 224 is a removable portion of the cover 204, and is processed into a shape that matches the shape of the medium 50, for example. More specifically, as described above, in this example, the cover 204 has an opening 220. In this case, it is preferable that the opening 220 is shaped to match the shape of the medium 50 so that, for example, no unnecessary gap is generated between the opening 220 and the medium 50. Therefore, in this example, the opening 220 is formed in the magnet sheet 224, and the magnet sheet 224 is held by the base portion 222, so that the opening 220 of the cover 204 is shaped to match the shape of the medium 50. Also, in this case, as shown in the figure, for example, base portion 222 has an opening larger than opening 220 of cover 204, and holds magnet sheet 224 so as to cover a part of this larger opening. With this configuration, for example, opening 220 that matches the shape of medium 50 can be appropriately formed in cover 204. Also, in this case, magnet sheet 224 in cover 204 can be considered, for example, as a member or the like that matches the shape of medium 50. And base portion 222 can be considered, for example, as a part or the like that has a fixed shape that is independent of the shape of medium 50.

[0028] The rotation mechanism 206 is a mechanism that rotates the medium 50 while holding the medium 50 at a position facing the nozzle row of the inkjet head 102. In this example, the rotation mechanism 206 has a shaft portion 226 and a rotation drive portion 228. The shaft portion 226 is a portion that rotatably holds the medium 50, and for example, holds the medium 50 rotatably at one end side and the other end side of the axial direction of the rotation shaft of the medium 50. For example, a chuck or the like that is suited to the medium 50 can be suitably used as the shaft portion 226. The rotation drive portion 228 is a drive portion that rotates the shaft portion 226, and rotates the medium 50 together with the shaft portion 226 by rotating the shaft portion 226. With this configuration, the rotation mechanism 206 can appropriately hold and rotate the medium 50. As described above, in the printing device 10 (see FIG. 1) of this example, the inkjet head 102 is moved relative to the position of the medium 50 facing the nozzle row by rotating the medium 50 during the main scanning operation. In this case, the control unit 30 (see FIG. 1) in the printing device 10 controls the operation of the rotation drive unit 228, for example, to control the rotation operation of the rotation mechanism 206 to rotate the medium 50. The control unit 30 also controls the operation of the inkjet head 102 and the rotation mechanism 206 via the main scanning drive unit 16 (see FIG. 1), for example, to cause the rotation mechanism 206 to eject ink from the inkjet head 102 while rotating the medium 50. In addition, the control unit 30 causes the inkjet head 102 to perform the main scanning operation. In this example, the rotation mechanism 206 rotates the medium 50 so that the direction of movement of the outer surface of the medium 50 at the position facing the nozzle row of the inkjet head 102 is the main scanning direction. With this configuration, for example, it is possible to cause the inkjet head 102 to perform the main scanning operation appropriately.

[0029] The ultraviolet irradiator 208 is an ultraviolet light source (UV light source) that irradiates ultraviolet light onto the outer surface (side surface) of the medium 50, and is disposed in a position adjacent to the medium 50 in the housing part 202 of the holding jig 40, thereby irradiating ultraviolet light onto the outer surface of the rotating medium 50. In addition, the ultraviolet irradiator 208 thereby cures the ink (ultraviolet curable ink) attached to the medium 50. In this example, the ultraviolet irradiator 208 has a lighting part 242 and a canopy 244, as shown in FIG. 3B, for example. The lighting part 242 is a part that generates ultraviolet light in the ultraviolet irradiator 208, and has, for example, a plurality of UVLEDs. The UVLEDs can be considered to be, for example, light emitting diodes that emit ultraviolet light. The lighting part 242 is turned on, for example, according to the control of the control part 30. The canopy 244 is a light shielding member (light shielding part) for blocking a part of the ultraviolet light generated by the lighting part 242. In this example, the canopy 244 is disposed between the inkjet head 102 and the lighting unit 242, thereby blocking ultraviolet light traveling in a direction toward the inkjet head 102. By using such a canopy 244, for example, stray light traveling toward the inkjet head 102 can be appropriately reduced.

[0030] In this example, the ultraviolet irradiator 208 irradiates the medium 50 with ultraviolet rays from a position farther from the inkjet head 102 than the top of the medium 50. In this case, the top of the medium 50 can be considered to be, for example, the position on the medium 50 closest to the inkjet head 102. With this configuration, for example, the ultraviolet irradiator 208 can be easily and appropriately covered by the cover 204. This also makes it possible to more appropriately reduce stray light traveling from the ultraviolet irradiator 208 toward the inkjet head 102. More specifically, in this example, the ultraviolet irradiator 208 irradiates ultraviolet rays toward a position downstream in the rotation direction of the medium 50 from the landing position where the ink lands on the medium 50 and at a rotation angle of 90 degrees to 180 degrees from the landing position in the rotation direction. With this configuration, for example, the ink that has landed on the medium 50 can be appropriately irradiated with ultraviolet rays. Such an ultraviolet ray irradiation position can be considered to be, for example, a position rotated 1 / 4 to 1 / 2 revolution in the rotation direction from the ink landing position on the medium 50. Also, the ultraviolet ray irradiator 208 is preferably installed at a position where the reflected light from the medium 50 is directed away from the inkjet head 102 (for example, downward).

[0031] The light source holding unit 210 is a platform-like member that holds the ultraviolet irradiator 208. In this example, the light source holding unit 210 holds the ultraviolet irradiator 208 on its upper surface, thereby holding the ultraviolet irradiator 208 at a position where the ultraviolet irradiator 208 can be irradiated toward the outer surface of the medium 50. The cover moving means 212 is a means for moving the cover 204 in the vertical direction. In this case, the vertical direction can be considered to be, for example, a direction in which the distance between the inkjet head 102 and the cover 204 changes. In this example, the cover moving means 212 is a means for moving the cover 204 by manual operation by the user, and for example, moves the base part 222 in the cover 204 in the vertical direction in response to the rotation of a handle for manual operation, thereby moving the magnet sheet 224 together with the base part 222. In addition, the cover moving means 212 moves the cover 204 in the vertical direction in response to the user's operation. In this case, it is considered that the cover moving means 212 moves the cover 204 in the vertical direction in accordance with, for example, the size of the medium 50. More specifically, in order to appropriately reduce stray light traveling from the ultraviolet irradiator 208 toward the inkjet head 102, it is important, for example, not to create a large gap between the cover 204 and the medium 50. In order to prevent such a gap, it is preferable to bring the edge of the opening 220 of the cover 204 sufficiently close to the medium 50. In order to do so, it is preferable to move the cover 204 appropriately in the vertical direction according to the size of the medium 50, for example. Therefore, in this example, the cover 204 is moved by the cover moving means 212, so that, for example, the gap between the cover 204 and the medium 50 is made sufficiently small. In this case, making the gap between the cover 204 and the medium 50 sufficiently small can be considered, for example, to substantially eliminate the gap in the lateral direction of the medium 50. The gap in the lateral direction of the medium 50 can be considered, for example, to be a gap in a direction perpendicular to the rotation axis of the medium 50. Substantially eliminating the gap in the lateral direction can be considered, for example, to be a matter of reducing the gap to a degree that does not affect the rotation of the medium 50 and does not cause problematic stray light. According to this example, for example, the medium 50 can be appropriately held by the holding jig 40.Furthermore, the ink that has landed on the medium 50 can be properly cured by the ultraviolet irradiator 208 in the holding jig 40 .

[0032] Next, the adjustment performed on the printing device 10 in this example will be described. FIG. 4 is a diagram for explaining the target of adjustment in one example of the adjustment performed on the printing device 10. FIG. 4(a) shows an example of a correct state in which adjustment is not required. The state shown in FIG. 4(a) can be considered, for example, as a state in which an appropriate adjustment is performed. FIG. 4(b) shows an example of a state in which adjustment is required. As described above, in this example, the inkjet head 102 has two nozzle rows 112. In this case, for example, as shown in FIG. 4(a), ink is ejected from the nozzle rows 112 to the medium 50 while one inkjet head 102 faces the medium 50. In this case, the main scanning drive unit 16 (see FIG. 1) ejects ink from each nozzle row 112 at a timing adjusted according to the difference in the position of each nozzle row 112, thereby causing the inkjet head 102 to eject ink to an ejection position set according to the printing resolution. In this case, the inkjet head 102 ejects ink of different colors from the multiple nozzle rows 112. More specifically, in the case shown in FIG. 4, the inkjet head 102 has a nozzle row 112 indicated as row A and a nozzle row 112 indicated as row B in the figure. The inkjet head 102 ejects magenta (M) ink from the nozzle row 112 of row A, and ejects black (K) ink from the nozzle row 112 of row B. In this case, if the position of the inkjet head 102 relative to the medium 50 is correctly adjusted, the magenta and black inks ejected into the same printing range will overlap in the same range, as shown in the right part of FIG. 4(a), for example.

[0033] However, for example, mechanical dimensional errors (mechanical dimensional errors) may occur in the positions of the holding jig 40, the inkjet head 102, etc. As a result, for example, the position of the inkjet head 102 relative to the medium 50 (the relative position of the inkjet head 102) may deviate from a reference position. In this case, the reference position may be considered to be, for example, a position corresponding to a predetermined correct position. Such a positional deviation may be, for example, a deviation between the center of the inkjet head 102 and the center of the medium 50 in the left-right direction (main scanning direction) in the figure. This left-right direction may be, for example, a direction perpendicular to the rotation axis of the medium 50.

[0034] In this regard, when printing is performed on a flat medium such as paper or film, rather than on a three-dimensional medium 50 as in this example, even if a deviation occurs in the relative position of the inkjet head 102 with respect to the medium 50, only the range printed on the medium 50 is shifted, and the content to be printed itself does not usually change. In contrast, when printing is performed on a three-dimensional medium 50 as in this example, if a deviation occurs in the relative position of the inkjet head 102 with respect to the medium 50, an unintended deviation occurs in the head gap, which is the distance between the inkjet head 102 and the medium 50 when ejecting ink. As a result, the content to be printed itself also changes. More specifically, as described above, in this example, with regard to the position in the left-right direction, the inkjet head 102 is made to eject ink by aligning the center position of the nozzle rows 112 of rows A and B in the inkjet head 102 with the rotation axis of the medium 50. In this case, if there is no deviation in the relative position of the inkjet head 102 with respect to the medium 50, the head gaps at the positions of the nozzle rows 112 of row A and row B will be the same distance, as shown in the left part of FIG. 4(a), for example. In contrast, if there is a deviation in the relative position of the inkjet head 102 with respect to the medium 50, the head gap at the position of one of the nozzle rows 112 of row A and row B will be larger than that shown in FIG. 4(a), and the head gap at the position of the other nozzle row 112 will be smaller than that shown in FIG. 4(a). For example, as shown in the left part of FIG. 4(b), the head gap at the position of the nozzle row 112 of row A that ejects magenta ink will be larger, and the head gap at the position of the nozzle row 112 of row B that ejects black ink will be smaller. In this case, the distance to land on the medium 50 of the ink ejected from one nozzle row 112 will be longer, and the distance to land on the medium 50 of the ink ejected from the other nozzle row 112 will be shorter, resulting in a deviation in the landing position. For example, in the case of Figure 4(b), the magenta ink will land to the right of the position assumed in the design, and the black ink will land to the left of the position assumed in the design.Furthermore, as a result, when magenta and black inks are ejected onto the same print range as designed, a deviation occurs in the range onto which the inks are ejected, as shown, for example, on the right side of FIG. 4(b).

[0035] Therefore, in order to print more appropriately on the three-dimensional medium 50, it is desirable to perform an adjustment on the printing device 10 to prevent the occurrence of the above-mentioned deviation in the range where the ink is discharged. In this example, as such an adjustment, an adjustment is performed on the relative position of the inkjet head 102 with respect to the medium 50, as described below. More specifically, as such an adjustment, for example, an adjustment is performed to align the center position of the inkjet head 102 with the center position of the medium 50 in the left-right direction. Such an adjustment can also be considered, for example, as an adjustment to reduce deviation in landing position for each nozzle row 112 for multiple nozzle rows 112 in one inkjet head 102 (adjustment of landing deviation for each nozzle row in one head). More specifically, in this example, such an adjustment is performed by causing the printing device 10 to print the patterns shown in FIG. 5 and FIG. 6, and appropriately changing the position of the inkjet head 102 according to the state of the printed pattern.

[0036] 5 and 6 are diagrams illustrating a pattern that the printing device 10 is made to draw when adjustments are made to the printing device 10. This pattern can be considered to be, for example, a pattern that the control unit 30 (see FIG. 1) in the printing device 10 makes the inkjet head 102 draw when adjustments are made. FIG. 5(a) is a diagram illustrating patterns 302a and b that the inkjet head 102 is made to draw. FIG. 5(b) shows an example of the state of patterns 302a and b that are drawn when there is no deviation in the relative position of the inkjet head 102 with respect to the medium 50. FIGS. 6(a) and 6(b) show an example of the state of patterns 302a and b that are drawn when there is a deviation in the relative position of the inkjet head 102 with respect to the medium 50.

[0037] During the adjustment described above, the control unit 30 of this example causes a plurality of nozzle rows 112 in one inkjet head 102 to draw predetermined patterns 302a and 302b. In this case, the inkjet head 102 draws the pattern 302a by ejecting ink from one of the two nozzle rows 112. Then, the inkjet head 102 draws the pattern 302b by ejecting ink from the other nozzle row 112. In this example, the pattern 302a is an example of a first pattern. The pattern 302b is an example of a second pattern. The one nozzle row 112 that draws the pattern 302a is an example of a first nozzle row. The other nozzle row 112 that draws the pattern 302b is an example of a second nozzle row different from the first nozzle row. In this case, the position of the one nozzle row 112 that draws the pattern 302a is an example of a first position. The position of the other nozzle row 112 that draws the pattern 302b is an example of a second position different from the first position. In addition, with respect to the operation of the inkjet head 102, the operation of drawing the pattern 302a by one nozzle row 112 is an example of an operation of drawing a first pattern by ink ejected from the nozzles in the nozzle row 112 in a state where the position of the nozzle row 112 relative to the medium 50 is at a first position. The operation of drawing the pattern 302b by the other nozzle row 112 is an example of an operation of drawing a second pattern by ink ejected from the nozzles in the nozzle row 112 in a state where the position of the nozzle row 112 relative to the medium 50 is at a second position. More specifically, in the case shown in FIG. 5(a), the inkjet head 102 draws the pattern 302a by the nozzle row A 112 that ejects magenta ink. Then, the inkjet head 102 draws the pattern 302b by the nozzle row B 112 that ejects black ink.

[0038] For convenience of illustration and explanation, the right side of FIG. 5(a) shows the difference in ink color by showing the pattern drawn in magenta with a dashed line and the pattern drawn in black with a solid line to distinguish between the different colors. Also, the patterns 302a and 302b are drawn with a shifted position. During actual adjustment, the control unit 30 causes the inkjet head 102 to draw the patterns 302a and 302b so that the patterns 302a and 302b overlap on the medium 50 in the main scanning direction corresponding to the left-right direction in the figure, as shown in FIG. 5(b), for example. In this case, the overlap of the patterns 302a and 302b in the design can be considered to mean that the patterns 302a and 302b overlap when the relative position of the inkjet head 102 with respect to the medium 50 is aligned with a reference position (not deviated from the reference position), for example. In this case, the patterns 302a and b, which are a plurality of patterns, can be considered to be patterns drawn at the same position in the main scanning direction on the medium 50 when the relative position of the inkjet head 102 with respect to the medium 50 is a reference position. The patterns 302a and b being drawn at the same position in the main scanning direction can be considered to be drawn at substantially the same position with an accuracy according to the quality required for printing, for example. In addition, when the medium 50 is rotated by the holding jig 40 (see FIG. 1) as in this example, the patterns 302a and b being drawn at the same position in the main scanning direction can be considered to be drawn at the same position in the rotation direction of the medium 50, for example.

[0039] More specifically, in this example, as shown in the left part of FIG. 5(a), for example, in regard to the positional relationship in the main scanning direction, the control unit 30 causes the inkjet head 102 to draw patterns 302a and b by ejecting ink from the nozzles in the nozzle rows 112 of rows A and B in the state where the relative position of the inkjet head 102 with respect to the medium 50 is fixed at a position where the nozzle row 112 of row A and the nozzle row 112 of row B are on opposite sides of the rotation axis for rotating the medium 50 by the rotation mechanism 206 (see FIG. 2) of the holding jig 40. With this configuration, for example, the patterns 302a and b can be appropriately drawn using the multiple nozzle rows 112 of one inkjet head 102. In this case, for example, in regard to the position in the main scanning direction, the center position between the nozzle row 112 of row A and the nozzle row 112 of row B in the inkjet head 102 is aligned with the position of the rotation axis of the medium 50, as in the case shown in FIG. 4(a). With this configuration, for example, when the relative position of the inkjet head 102 with respect to the medium 50 is aligned with a reference position, it is possible to appropriately align the head gaps at the positions of the multiple nozzle rows 112. This also makes it possible for the inkjet head 102 to easily and appropriately draw overlapping patterns 302a, b on the medium 50 when the relative position of the inkjet head 102 is aligned with a reference position.

[0040] In this example, if the relative position of the inkjet head 102 with respect to the medium 50 is shifted from the reference position, the landing position is shifted, and as shown in Figs. 6(a) and 6(b), the positions (positions in the main scanning direction) where the patterns 302a and 302b are drawn on the medium 50 are shifted. More specifically, in this example, if the medium 50 is rotated in the rotation direction shown by the arrow in the figure, if the head gap becomes smaller due to the shift in the relative position of the inkjet head 102, the amount of rotation of the medium 50 until the ink lands becomes smaller, and the landing position is shifted to the left in the figure, which is the downstream side of the rotation direction of the medium 50. In addition, if the head gap becomes larger, the amount of rotation of the medium 50 until the ink lands becomes larger, and the landing position is shifted to the right in the figure, which is the upstream side of the rotation direction of the medium 50. In addition, Fig. 6(a) shows an example in which the relative position of the inkjet head 102 with respect to the medium 50 is shifted to the right in the figure, as shown in the left part of the figure. In this case, as shown in the right part of the figure, the state of the patterns 302a and b is such that the pattern 302a corresponding to the nozzle row 112 of row A is shifted to the left with respect to the pattern 302b corresponding to the nozzle row 112 of row B. Therefore, in this case, it is considered to adjust the position of the inkjet head 102 to move it to the left based on the state of the patterns 302a and b. Also, FIG. 6(b) shows an example in which the relative position of the inkjet head 102 with respect to the medium 50 is shifted to the left in the figure, as shown in the left part of the figure. In this case, as shown in the right part of the figure, the state of the patterns 302a and b is such that the pattern 302a is shifted to the right with respect to the pattern 302b. Therefore, in this case, it is considered to adjust the position of the inkjet head 102 to move it to the right based on the state of the patterns 302a and b. Therefore, according to this example, it is possible to appropriately detect, for example, whether the relative position of the inkjet head 102 with respect to the medium 50 is aligned with the reference position. This also makes it possible to appropriately adjust the relative positions of the inkjet heads 102, for example, as necessary.

[0041] Here, in this example, the state where the patterns 302a and 302b overlap can be considered as, for example, a state where there is no problem with the relative position of the inkjet head 102. Therefore, in this case, for example, by adjusting the relative position of the inkjet head 102 so that the patterns 302a and 302b overlap, the relative position of the inkjet head 102 can be appropriately adjusted. Also, in this case, by appropriately adjusting the relative position of the inkjet head 102, for example, printing can be performed more appropriately on a three-dimensional medium 50. Also, in the inkjet head 102 of this example, the relative positions of the multiple nozzle rows 112 are in a known relationship and are formed at predetermined positions in the inkjet head 102. And, in this case, adjusting the relative position of the inkjet head 102 with respect to the medium 50 can be considered to correspond to, for example, adjusting the relative position of the nozzle row 112 with respect to the medium 50. Also, in this case, the patterns 302a and 302b can be considered as, for example, patterns for adjusting the deviation of the landing position occurring between the multiple nozzle rows 112 with known relative positions. In addition, adjusting the relative position of the inkjet head 102 can also be thought of as, for example, adjusting the relative positions of the nozzle rows 112 with respect to the medium 50 without changing the relative positional relationship between the nozzle rows 112.

[0042] As can be understood from the above description, in this example, when the relative position of the inkjet head 102 with respect to the medium 50 is misaligned, the patterns 302a and 302b are misaligned in a direction corresponding to the direction in which the relative position of the inkjet head 102 is misaligned. Therefore, the patterns 302a and 302b can be considered as, for example, patterns for detecting the direction of misalignment of the relative position of the inkjet head 102. In this case, for example, the greater the misalignment of the relative position of the inkjet head 102, the greater the misalignment of the patterns 302a and 302b. Therefore, the patterns 302a and 302b can be considered as, for example, patterns whose overlapping state changes depending on the degree of misalignment of the relative position of the inkjet head 102 when the relative position of the inkjet head 102 is misaligned from the reference position. In addition, in a modified example of the adjustment operation for the printing device 10, when the adjustment of the relative position of the inkjet head 102 is performed with higher accuracy, for example, a pattern for detecting the magnitude of misalignment of the relative position of the inkjet head 102 can be further used. In this case, in addition to the patterns 302a and 302b described above, it is possible to use, for example, patterns that overlap when the magnitude of the deviation in the relative position of the inkjet head 102 is a predetermined magnitude. As such patterns, it is also possible to use, for example, a plurality of sets of patterns that have different magnitudes of deviation when the patterns overlap. With this configuration, it is possible to appropriately detect, for example, the magnitude of the deviation in the relative position of the inkjet head 102.

[0043] As described above, in this example, the printing device 10 includes a plurality of inkjet heads 102. In this case, for example, it is possible to adjust the relative position of any of the inkjet heads 102 with respect to the medium 50. In this case, it is possible to adjust the position of the other inkjet heads 102 with respect to the inkjet head 102 whose relative position with respect to the medium 50 has been adjusted. With this configuration, for example, the positions of the plurality of inkjet heads 102 can be appropriately adjusted. In this case, the control unit 30 of the printing device 10 causes, for example, the plurality of inkjet heads 102 to draw a pattern for detecting a deviation in the distance between the inkjet heads 102. Such a pattern can be considered, for example, as a head-to-head distance adjustment pattern used when adjusting the distance between the inkjet heads 102. In this case, regarding the operation of the control unit 30, for example, it can be considered that, in addition to the patterns 302a and 302b described above, a head-to-head distance adjustment pattern is drawn on the plurality of inkjet heads 102. More specifically, it is possible to adjust the distance between the inkjet heads 102 as shown in FIG. 7.

[0044] FIG. 7 is a diagram for explaining adjustment of the distance between the inkjet heads 102. FIGS. 7(a) and 7(b) are diagrams for explaining problems that occur when the distance between the inkjet heads 102 is misaligned. FIG. 7(a) shows an example of a printing operation performed when there is no misalignment in the distance between the inkjet heads 102. FIG. 7(b) shows an example of a printing operation performed when there is a misalignment in the distance between the inkjet heads 102. As described above, in this example, the inkjet heads 102 are moved in sequence to directly above the rotating medium 50 to face the medium 50. In addition, the control unit 30 thereby causes the inkjet heads 102 to eject ink onto the medium 50 in sequence. In this case, the control unit 30 moves the head unit 12 (see FIG. 1) having the inkjet heads 102 according to the designed distance between the inkjet heads 102.

[0045] In this case, if the inkjet heads 102 are attached to the head unit 12 at the correct positions and there is no deviation in the distance between the inkjet heads 102, the inkjet heads 102 always face the medium 50 correctly even when the inkjet heads 102 facing the medium 50 are changed, as shown in FIG. 7(a), for example. More specifically, in this case, if the relative position of the inkjet head 102 on the leftmost side in the figure is adjusted correctly with respect to the medium 50, the inkjet heads 102 from the second left onwards (the second, third and fourth) can be moved appropriately to immediately above the medium 50 in sequence. In addition, this allows, for example, all the inkjet heads 102 to appropriately eject ink by aligning the center position of the inkjet head 102 with the center position of the medium 50, for example, with respect to the position in the main scanning direction. However, if there is a deviation in the distance between the inkjet heads 102 at any position in the head unit 12, as shown in FIG. 7(b), the inkjet head 102 that is to be newly faced to the medium 50 will not face the medium 50 correctly. More specifically, in the case shown in FIG. 7(b), the distance Lh between the leftmost inkjet head 102 in the figure and the adjacent inkjet head 102 (the second inkjet head 102) is greater than the correct distance (the original distance). In this case, since the actual distance Lh cannot be known, the control unit 30 moves the head unit 12 based on the designed distance between the inkjet heads 102. As a result, the positions of the second and subsequent inkjet heads 102 are shifted from directly above the medium 50. In this case, if printing is performed in this state, the ink landing position will be shifted, making it impossible to print properly.

[0046] In contrast, in this example, the distance between the inkjet heads 102 is further adjusted by causing the inkjet heads 102 to draw patterns 304a and b shown in Fig. 7(c), for example. Fig. 7(c) shows an example of patterns 304a and b used when adjusting the distance between the inkjet heads 102. The patterns 304a and b can be considered, for example, as patterns used for adjustments to accommodate variations in the distance between the inkjet heads 102. Furthermore, the patterns 304a and b can also be considered, for example, as patterns for detecting deviations in landing positions that occur between the inkjet heads 102.

[0047] As described above, in this example, the inkjet head 102 has two nozzle rows 112. In this case, the control unit 30 causes one of the inkjet heads 102 to draw the pattern 304a with ink ejected from the nozzles in one of the nozzle rows 112. In addition, the control unit 30 causes one of the other inkjet heads 102 to draw the pattern 304b with ink ejected from the nozzles in one of the nozzle rows 112. In this case, the control unit 30 sets, for example, one of the inkjet heads 102 in the head unit 12 as a reference inkjet head 102 and causes the inkjet head 102 to draw the pattern 304a. Then, one inkjet head 102 to be aligned with the reference inkjet head 102 is selected and causes the inkjet head 102 to draw the pattern 304b. In this case, it is preferable to use different patterns as the patterns 304a and b, for example, as shown in the figure. With this configuration, for example, the patterns 304a and 304b can be easily and appropriately distinguished from each other. As the patterns 304a and 304b, for example, a pattern that at least partially overlaps on the medium 50 when the distance between the inkjet heads 102 is correct can be suitably used. More specifically, in this example, the pattern 304a includes vertical lines extending in the up-down direction and horizontal lines extending in the left-right direction in the figure. In contrast, the pattern 304b includes only vertical lines, not horizontal lines. When the distance between the inkjet heads 102 is correct, for example, the vertical line portion of the pattern 304a overlaps with the vertical line portion of the pattern 304b on the medium 50. With this configuration, for example, it is possible to appropriately detect whether the distance between the inkjet heads 102 is correct. In addition, for example, based on the detection result, it is possible to appropriately adjust the distance between the inkjet heads 102.

[0048] FIG. 7(c) shows an example of the state of patterns 304a and 304b when the distance between the inkjet heads 102 is misaligned and adjustment is required. More specifically, FIG. 7(c) shows an example of a case where a pattern 304b drawn by the inkjet head 102 to be adjusted is drawn on the left side of the drawing, compared to a pattern 304a drawn by a reference inkjet head 102. In this case, for example, it can be considered that the distance between the inkjet heads 102 is greater than the correct distance, and therefore the ejection position of the inkjet head 102 to be adjusted is shifted to the left side of the correct position. Conversely to the illustrated case, when the pattern 304b is drawn on the right side of the drawing, compared to the pattern 304a, it can be considered that the distance between the inkjet heads 102 is narrower than the correct distance, and therefore the ejection position of the inkjet head 102 to be adjusted is shifted to the right side of the correct position. In this example, the adjustment of the distance between the inkjet heads 102 can be, for example, by adjusting the movement distance of the head unit 12 when changing the inkjet head 102 that faces the medium 50. More specifically, for example, if the distance between the inkjet heads 102 is greater than the correct distance, an adjustment may be made to lengthen the movement distance. Also, if the distance between the inkjet heads 102 is narrower than the correct distance, an adjustment may be made to shorten the movement distance. With this configuration, for example, even if the distance between the inkjet heads 102 is off from the correct distance, printing operation using the multiple inkjet heads 102 can be performed appropriately.

[0049] In this example, the patterns 304a and 304b can be considered to be patterns whose state changes depending on the distance between the inkjet heads 102. In a modified example of the adjustment operation for the printing device 10, when the adjustment of the distance between the inkjet heads 102 is performed with higher accuracy, for example, a pattern for detecting the magnitude of the deviation in the distance between the inkjet heads 102 can be further used. In this case, in addition to the patterns 304a and 304b described above, for example, a pattern that overlaps when the magnitude of the deviation in the distance between the inkjet heads 102 is a predetermined magnitude can be used. As such a pattern, for example, a plurality of sets of patterns whose overlapping deviations are different from each other can be used. With this configuration, for example, the magnitude of the deviation in the distance between the inkjet heads 102 can be appropriately detected.

[0050] Next, supplementary explanations and explanations of modified examples of each of the configurations described above will be given. As described above, in this example, the inkjet head 102 is caused to eject ink based on the control of the control unit 30 of the printing device 10, thereby performing adjustments on the printing device 10. In addition, as this adjustment, for example, adjustments are performed on the relative position of the inkjet head 102 with respect to the medium 50 and adjustments on the distance between the inkjet heads 102. In this case, the printing device 10 can be considered to have an adjustment function for performing such adjustments. In addition, such adjustments can also be considered to be, for example, adjustments on the landing positions of ink of each color ejected from the multiple inkjet heads 102. In addition, the pattern drawn by the inkjet head 102 during adjustment can be considered to be, for example, an adjustment pattern used to adjust the landing positions. And according to this example, for example, when a deviation occurs in the landing position of ink ejected from any of the inkjet heads 102, it is possible to clearly present to the user (adjuster) performing the adjustment that the landing position is deviated. In addition, this allows, for example, adjustments on the printing device 10 to be easily and appropriately performed. In addition, in the printing device 10 of this example, at least some of the inkjet heads 102 can be considered to be aligned in a direction perpendicular to the direction of the rotation axis of the medium 50. In this case, in order to properly align the landing positions of the ink ejected from all the nozzle rows 112 of all the inkjet heads 102, it is necessary to align the centers of the inkjet heads 102 with the center of the medium 50 in the left-right direction (main scanning direction). Furthermore, in addition to that, a function for adjusting the deviation of the distance between the inkjet heads 102 is further required for the multiple inkjet heads 102. In response to this, as described above, according to this example, for example, it is possible to properly realize these adjustment functions. This also makes it possible to more appropriately perform printing on, for example, a three-dimensional medium 50.

[0051] In the above, the adjustment of the relative position of the inkjet head 102 with respect to the medium 50 has been described mainly with respect to the operation using the multiple nozzle rows 112 in one inkjet head 102. In contrast, in a modified adjustment operation, for example, it is possible to perform the adjustment using only one nozzle row 112 in the inkjet head 102. In this case, for example, it is possible to use any one nozzle row 112 in the inkjet head 102 having multiple nozzle rows 112. In addition, in a modified configuration of the printing device 10, for example, it is possible to use an inkjet head 102 having only one nozzle row 112 instead of an inkjet head 102 having multiple nozzle rows 112. More specifically, in this case, it is possible to perform the adjustment of the relative position of the inkjet head 102 with respect to the medium 50 by the operation shown in FIG. 8.

[0052] FIG. 8 is a diagram showing a modified example of the adjustment operation for the printing device 10, and shows an example of the operation of adjusting the relative position of the inkjet head 102 with respect to the medium 50 using one nozzle row 112 in the inkjet head 102. FIGS. 8(a) and 8(b) show an example of the adjustment operation. As described above, when adjusting the relative position of the inkjet head 102 with respect to the medium 50, if an inkjet head 102 having a plurality of nozzle rows 112 is used, the patterns 302a and 302b (see FIG. 5) are drawn by ejecting ink from the nozzles of the plurality of nozzle rows 112 at different positions, for example, by the operation shown in FIG. 5(a). On the other hand, in the case of the modified example shown in FIG. 8(a), the control unit 30 of the printing device 10 causes the inkjet head 102 to draw a pattern corresponding to the pattern 302a with the inkjet head 102 in a first position relative to the medium 50, as shown in the left part of the figure, for example. Then, as shown in the right part of the figure, for example, the control unit 30 moves the inkjet head 102 relative to the medium 50 to set the relative position of the inkjet head 102 with respect to the medium 50 to a second position different from the first position. Then, at that position, the control unit 30 causes the inkjet head 102 to write a pattern corresponding to the pattern 302b. Even with this configuration, for example, it is possible to appropriately detect a deviation in the relative position of the inkjet head 102 with respect to the medium 50. This also makes it possible to more appropriately print on a three-dimensional medium 50, for example.

[0053] Also, a change in the landing position caused by a shift in the relative position of the inkjet head 102 with respect to the medium 50 may be detected by changing the rotation direction of the medium 50, for example, as shown in FIG. 8(b). In this case, the operation of the control unit 30 may be considered to be, for example, causing the inkjet head 102 to draw patterns corresponding to the patterns 302a and 302b by changing the rotation direction of the medium 50. More specifically, in this case, as shown in the left part of the figure, for example, in a state where the medium 50 is rotated in a first rotation direction by the rotation mechanism 206 (see FIG. 2) in the holding jig 40, the control unit 30 causes the inkjet head 102 to draw a pattern corresponding to the pattern 302a with ink ejected from the nozzles in the nozzle row 112. Then, after that, as shown in the right part of the figure, for example, while the medium 50 is rotated by the rotation mechanism 206 in a second rotation direction opposite to the first rotation direction, the control unit 30 causes the inkjet head 102 to draw a pattern corresponding to the pattern 302b with ink ejected from the nozzles in the nozzle row 112. Even with this configuration, for example, it is possible to appropriately detect a deviation in the relative position of the inkjet head 102 with respect to the medium 50. This also makes it possible to more appropriately print on a three-dimensional medium 50, for example.

[0054] In addition, in a further modified example of the adjustment operation for the printing device 10, for example, it is possible to adjust the relative position of the inkjet head 102 with respect to the medium 50 using a plurality of inkjet heads 102 whose relative positions have been appropriately and sufficiently adjusted. In this case, for example, it is possible to use a head group in which the positions of the plurality of inkjet heads 102 are already fixed. In addition, in this case, it is possible to consider that the operation described with reference to, for example, Figs. 5 and 6 is performed using a plurality of nozzle rows 112 in the plurality of inkjet heads 102. More specifically, in this case, the control unit 30 causes, for example, a first inkjet head 102 of the plurality of inkjet heads 102 to draw a pattern corresponding to the pattern 302a, and causes a second inkjet head 102 different from the first inkjet head 102 to draw a pattern corresponding to the pattern 302b. Even in this configuration, for example, it is possible to appropriately detect the deviation of the relative position of the inkjet head 102 with respect to the medium 50.

[0055] As described above, in this example, the printing device 10 prints on the medium 50 while rotating the medium 50. In this case, for example, a cylindrical (cylindrical) medium 50 can be preferably used as the medium 50. In this case, the cylindrical medium can be considered as an example of a medium having a shape of a rotating body whose cross section in a plane perpendicular to the rotation axis is a circle. In addition, it is also possible to use a medium 50 having a shape other than a cylindrical shape. For example, a medium 50 having a shape of a rotating body can be preferably used as the medium 50 having a shape other than a cylindrical shape. For example, a medium 50 having a shape of a cone or a truncated cone (a truncated cone shape) can be used as such a medium 50. In addition, when a medium 50 having a shape such as a cone or a truncated cone is used, the holding jig 40 holds the medium 50 so that the height of the medium 50 at the position facing the inkjet head 102 (the position where the ink lands) is constant. In this case, for example, it is possible to hold the medium 50 so that the generating line of the medium 50, which is cone-shaped or the like, at the position facing the inkjet head 102 is horizontal by appropriately tilting the rotation axis that rotates the medium 50 relative to the horizontal direction.

[0056] In addition, with regard to the operation of printing on the medium 50 of various shapes as described above, in the printing device 10, for example, when at least some shapes of the medium 50 are used, it is considered to use multiple nozzle rows 112 in the inkjet head 102. More specifically, when a medium 50 having a shape in which the cross-sectional shape in a plane perpendicular to the rotation axis is constant or substantially constant, such as a cylindrical or substantially cylindrical medium 50, is used, it is considered to perform printing using multiple nozzle rows 112 in the inkjet head 102. In this case, the adjustment of the relative position of the inkjet head 102 with respect to the medium 50 can be easily and appropriately performed by the operation described with reference to, for example, FIGS. 5 and 6. On the other hand, when a medium 50 having a shape more complicated than that of the cylindrical medium 50, such as a conical or truncated conical medium 50, is used, if higher quality printing is desired, it may be preferable to use only one nozzle row 112 in the inkjet head 102. Therefore, in such a case, it is also possible to perform printing using only one of the multiple nozzle rows 112 in the inkjet head 102, for example. In this case, for example, it is possible to align the position of the nozzle row 112 to be used with the position of the rotation axis in the main scanning direction. Depending on the method of controlling the printing operation, the position of the nozzle row 112 to be used may be shifted from the position of the rotation axis as necessary. In this case, too, it is possible to adjust the relative position of the inkjet head 102 with respect to the medium 50 by, for example, using a plurality of nozzle rows 112 in the inkjet head 102, through the operations described with reference to FIGS. 5 and 6. It is also possible to adjust the relative position of the inkjet head 102 with respect to the medium 50 by, for example, the operations described with reference to FIGS. 8(a) and (b), depending on the required accuracy of adjustment, etc.

[0057] In addition, in the case of printing on a three-dimensional medium 50, the problem of the head gap changing due to the displacement of the relative position of the inkjet head 102 with respect to the medium 50 can be considered to occur, for example, in cases other than when the medium 50 is rotated. Therefore, even when the medium 50 is not rotated, the same or similar adjustment as described above may be performed with respect to the relative position of the inkjet head 102 with respect to the medium 50. In this case, too, for example, the inkjet head 102 can be caused to draw patterns corresponding to the patterns 302a and b with ink ejected from the nozzles of the nozzle row at different positions, thereby making it possible to appropriately perform adjustment regarding the relative position of the inkjet head 102 with respect to the medium 50. In addition, regarding the adjustment regarding the relative position of the inkjet head 102 with respect to the medium 50, for example, in the case of a configuration in which the medium 50 is rotated, the positional relationship between the rotation axis of the medium 50 and the inkjet head 102 can be considered to be important. Therefore, in this case, for example, it is preferable to perform adjustment by moving the inkjet head 102 relative to the medium 50 so that the position of the inkjet head 102 with respect to the rotation axis becomes a predetermined position. In contrast, when printing on a three-dimensional medium 50 without rotating the medium 50, it is possible to adjust the relative position of the inkjet head 102 with respect to the medium 50, for example, by making an adjustment without moving the inkjet head 102 relative to the medium 50. In this case, it is also possible to make an adjustment, for example, by changing the timing at which the inkjet head 102 ejects ink. [Industrial Applicability]

[0058] The present invention can be suitably used in, for example, a printing device. [Explanation of symbols]

[0059] 10 printing device, 102 inkjet head, 112 nozzle row, 12 head section, 14 base section, 16 main scanning drive section, 18 sub-scanning drive section, 20 sensor, 202 housing section, 204 cover, 206 rotation mechanism, 208 ultraviolet irradiator, 210 light source holder, 212 cover moving means, 22 sensor moving means, 220 opening, 222 base section, 224 magnet sheet, 226 shaft section, 228 rotation drive section, 242 lighting section, 244 visor, 30 control section, 302 pattern, 304 pattern, 40 holding jig, 50 medium

Claims

1. A printing device that prints on a three-dimensional medium, an inkjet head having a nozzle row in which a plurality of nozzles are arranged at different positions in a predetermined nozzle row direction; a main scanning drive unit that causes the inkjet head to perform a main scanning operation of ejecting ink while moving in a main scanning direction that is set in advance relative to a position on the medium facing the nozzle row; a control unit for controlling operations of the inkjet head and the main scanning drive unit; Equipped with During adjustment of the printing device, the control unit causes the inkjet head to write a first pattern and a second pattern; the first pattern and the second pattern are patterns that are drawn at the same position in the main scanning direction of the medium when a position of the inkjet head relative to the medium is a predetermined reference position, The printing device is characterized in that the inkjet head draws the first pattern by ink ejected from the nozzles in the nozzle row when the position of the nozzle row relative to the medium is at a first position, and draws the second pattern by ink ejected from the nozzles in the nozzle row when the position of the nozzle row relative to the medium is at a second position different from the first position.

2. the medium is held by a holding member disposed at a position facing the inkjet head; the holding member includes a rotation mechanism that rotates the medium while holding the medium at a position facing the nozzle row, The printing device according to claim 1 , wherein the main scanning drive unit moves the inkjet head in the main scanning direction relative to a position on the medium facing the nozzle row by rotating the medium using the rotation mechanism.

3. 3. The printing device according to claim 2, wherein the inkjet head has a plurality of nozzle rows that are positioned differently in the main scanning direction, and the first pattern is drawn by ejecting ink from the nozzles in a first nozzle row, and the second pattern is drawn by ejecting ink from the nozzles in a second nozzle row that is different from the first nozzle row.

4. 4. The printing device according to claim 3, wherein, with respect to a positional relationship in the main scanning direction, a relative position of the inkjet head with respect to the medium is fixed such that the first nozzle row and the second nozzle row are on opposite sides of a rotation axis about which the rotation mechanism rotates the medium, and the control unit causes the inkjet head to write the first pattern and the second pattern by ejecting ink from the nozzles in the first nozzle row and the nozzles in the second nozzle row.

5. 2. The printing device according to claim 1, wherein the first pattern and the second pattern are patterns whose overlapping state changes depending on the degree of positional deviation when the position of the inkjet head relative to the medium is deviated from the reference position.

6. A plurality of the inkjet heads are provided, The printing device according to claim 5 , wherein the control unit further controls the inkjet heads to write a pattern whose state changes depending on the distance between the inkjet heads.

7. A printing device that prints on a three-dimensional medium held by a holding member that holds a medium to be printed, comprising: an inkjet head having a nozzle row in which a plurality of nozzles are arranged at different positions in a predetermined nozzle row direction; a main scanning drive unit that causes the inkjet head to perform a main scanning operation of ejecting ink while moving in a main scanning direction that is set in advance relative to a position on the medium facing the nozzle row; a control unit for controlling operations of the inkjet head and the main scanning drive unit; Equipped with the holding member includes a rotation mechanism that rotates the medium while holding the medium at a position facing the nozzle row, the main scanning drive unit causes the rotation mechanism to rotate the medium, thereby moving the inkjet head in the main scanning direction relative to a position on the medium facing the nozzle row; During adjustment of the printing device, the control unit causes the inkjet head to write a first pattern and a second pattern; the first pattern and the second pattern are patterns that are drawn at the same position in the main scanning direction of the medium when a position of the inkjet head relative to the medium is a predetermined reference position, while the medium is rotated in a first rotation direction by the rotation mechanism, the inkjet head writes the first pattern by ink ejected from the nozzles in the nozzle row; A printing device characterized in that, while the medium is rotated by the rotation mechanism in a second rotation direction opposite to the first rotation direction, the inkjet head draws the second pattern by ink ejected from the nozzles in the nozzle row.

8. An adjustment method for adjusting a printing device that prints on a three-dimensional medium, comprising the steps of: causing an inkjet head of the printing device to write a first pattern and a second pattern; the inkjet head has a nozzle row in which a plurality of nozzles are arranged at different positions in a predetermined nozzle row direction, causing the inkjet head to perform a main scanning operation in which the ink is ejected while moving in a main scanning direction set in advance relative to a position on the medium facing the nozzle row; the first pattern and the second pattern are patterns that are drawn at the same position in the main scanning direction of the medium when a position of the inkjet head relative to the medium is a predetermined reference position, an adjustment method comprising: causing the inkjet head to draw the first pattern by ink ejected from the nozzles in the nozzle row when the position of the nozzle row relative to the medium is at a first position; and causing the inkjet head to draw the second pattern by ink ejected from the nozzles in the nozzle row when the position of the nozzle row relative to the medium is at a second position different from the first position.

9. 1. An adjustment method for adjusting a printing device that prints on a three-dimensional medium held by a holding member that holds a medium to be printed, comprising: causing an inkjet head of the printing device to write a first pattern and a second pattern; the inkjet head has a nozzle row in which a plurality of nozzles are arranged at different positions in a predetermined nozzle row direction, causing the inkjet head to perform a main scanning operation in which the ink is ejected while moving in a main scanning direction set in advance relative to a position on the medium facing the nozzle row; the holding member includes a rotation mechanism that rotates the medium while holding the medium at a position facing the nozzle row, In the main scanning operation, the medium is rotated by the rotation mechanism, thereby moving the inkjet head in the main scanning direction relative to a position on the medium facing the nozzle row; the first pattern and the second pattern are patterns that are drawn at the same position in the main scanning direction of the medium when a position of the inkjet head relative to the medium is a predetermined reference position, causing the inkjet head to write the first pattern by ejecting ink from the nozzles in the nozzle row while rotating the medium in a first rotation direction by the rotation mechanism; an adjustment method characterized by causing the inkjet head to draw the second pattern by ink ejected from the nozzles in the nozzle row while rotating the medium by the rotation mechanism in a second rotation direction opposite to the first rotation direction.

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