Inkjet recording device

Abstract

To provide an inkjet recording device that can execute recording of images on a plurality of surfaces of a medium to be recorded in a three-dimensional shape, with a simple structure thereof.SOLUTION: An inkjet recording device is provided with: a recording head; placing means on which a medium to be recorded having a first surface and a second surface is placed; turning means that turns the recording head; first moving means that moves the recording head in a first direction; second moving means that moves the medium to be recorded in a second direction; and recording control means that executes recording operation of making ink impact on the first surface by making the recording head discharge ink while moving the recording head in the first direction in a state where the nozzle surface is made to oppose to the first surface, and operation of moving the medium to be recorded in the second direction after the recording operation, and then executes recording operation of making ink impact on the second surface by making the recording head discharge ink while moving the recording head in the first direction in a state where the nozzle surface is made to oppose to the second surface by turning of the recording head by the turning means.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an inkjet recording apparatus. [Background technology]

[0002] Conventionally, as an image recording device that directly records an image on a recording medium, there has been known an inkjet recording device that records an image by ejecting ink onto the recording medium while scanning an inkjet head having a nozzle row in which a plurality of nozzles that eject ink are arranged in a predetermined direction. In recent years, various inkjet recording devices that record an image on the outer surface of a recording medium having a three-dimensional shape have been proposed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-126825 [Patent Document 2] JP 2016-172379 A [Patent Document 3] Patent No. 7148189 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, there has been a demand for inkjet recording devices that can perform image recording on multiple surfaces, such as printing on a first surface of a three-dimensional recording medium and then printing on a second surface different from the first surface, such as recording an image on the entire top, side, and back surface of a plate-shaped recording medium with a single inkjet recording device.

[0005] For example, Patent Document 1 proposes an inkjet recording device that includes a support table that supports a three-dimensional, plate-shaped recording medium, and a mechanism for rotating the supported recording medium about a vertical axis and a mechanism for rotating the supported recording medium about a horizontal axis, and that records an image on the top and sides of the plate-shaped recording medium by rotating the recording medium itself while keeping the recording head fixed in a direction that ejects ink from above to below in the vertical direction.

[0006] However, in the case of an inkjet recording device that rotates a recording medium to record an image on the top or side surface as proposed in Patent Document 1, it may be difficult to hold and rotate the recording medium if the recording medium is heavy. Also, in the case of a large-sized recording medium, the device may become huge in the height direction in order to secure a space to rotate the recording medium, which may require a wide installation space with a high ceiling and may lead to an increase in the cost of the device.

[0007] Moreover, Patent Document 2 proposes an inkjet recording device in which a recording head is mounted on the tip of an arm-type robot to record an image on a recording target having a three-dimensional shape.

[0008] However, arm-type robots such as the one proposed in Patent Document 2 have issues such as the expense of the arm-type robot itself, and issues regarding improving the image quality of the recorded images during the moving section are anticipated because it is relatively difficult to achieve precision in the speed and amount of movement compared to linear motors or ball screws.

[0009] Furthermore, Patent Document 3 proposes an inkjet recording device that rotates a carriage carrying a recording head about a vertical axis on a three-dimensional recording medium, and simultaneously moves a first horizontal axis and a second axis perpendicular to the first axis to adjust the distance between the outer surface of the recording medium and the recording head while recording an image.

[0010] However, in the case of an inkjet recording device such as that proposed in Patent Document 3, the device configuration may become complicated due to the need to perform synchronous control of the drive axes to simultaneously move the carriage along the first and second axes, which may lead to increased costs.

[0011] The present invention has been made in consideration of the above-mentioned problems, and aims to solve the above-mentioned problems and provide an inkjet recording device that can record images on multiple surfaces of a three-dimensional recording medium with a simple device configuration. [Means for solving the problem]

[0012] In order to achieve the above object, the inventors of the present invention have intensively invented and found the following configuration.

[0013] That is, in the present invention, in an inkjet recording apparatus for recording an image on a three-dimensional recording medium having at least a first surface and a second surface different from the first surface on the outer surface, a recording head having a nozzle surface on which a plurality of nozzles for ejecting ink onto an outer surface of a recording medium are arranged in a predetermined direction; A placement means for placing the recording medium; a rotating means for rotating the recording head about a rotation axis in a direction intersecting the predetermined direction to change the orientation of the nozzle surface; a first moving means for moving the recording head in a first direction intersecting the predetermined direction; a second moving means for moving the recording medium placed on the placement means in a second direction substantially perpendicular to the first direction; When an image is recorded on the first surface, a recording operation is performed in which the recording head is moved in the first direction by the first moving means with the nozzle surface facing the first surface, while the ink is ejected from the nozzles and the ink lands on the first surface, and an operation is performed in which the recording medium placed on the placement means is moved in the second direction by the second moving means after the recording operation, a recording control means for executing a recording operation in which, when an image is recorded on the second surface, the recording head is rotated by the rotating means so that the nozzle surface faces the second surface, while the recording head is moved in the first direction by the first moving means, so that the ink is ejected from the nozzles and the ink lands on the second surface; has. Effect of the Invention

[0014] According to the present invention, by adopting the above-mentioned configuration, the above-mentioned problem can be solved, and an inkjet recording device capable of recording images on multiple surfaces of a three-dimensional recording medium with a simple device configuration can be provided. [Brief description of the drawings]

[0015] [Figure 1] 1 is a schematic perspective view showing an example of the configuration of an inkjet recording apparatus according to an embodiment of the present invention; [Diagram 2] 1 is a schematic front view illustrating an example of the configuration of an inkjet recording apparatus according to an embodiment of the present invention. [Diagram 3] 4 is a schematic side view showing an example of the configuration of a carriage and its surroundings; FIG. [Figure 4] 2A to 2C are schematic diagrams showing examples of shapes of a recording medium. [Diagram 5] 1 is a block diagram showing an example of the hardware configuration of an inkjet recording apparatus according to an embodiment of the present invention; [Figure 6] 10A to 10C are schematic diagrams illustrating an example of the operation of the carriage when printing on each of the first, second, and third sides. [Figure 7] 5 is a flowchart showing an example of a sequence for printing on a first side of a recording medium by the inkjet recording apparatus according to the present embodiment. [Figure 8] 10 is a flowchart showing an example of a sequence for printing on a second surface of a recording medium by the inkjet recording apparatus according to the present embodiment when the second surface is flat. [Figure 9]5 is a flowchart showing an example of a sequence for printing on a third side, opposite to the first side, of a recording medium by the inkjet recording apparatus according to the present embodiment. [Figure 10] 10A to 10C are schematic diagrams showing an example of the operation of the carriage when the second surface has a curved surface. [Figure 11] 10 is a flowchart showing an example of a sequence for printing on a second surface of a recording medium by the inkjet recording apparatus according to the present embodiment when the second surface of the recording medium has a curved surface. [Figure 12] 10A to 10C are schematic diagrams illustrating an example of the operation of the carriage and the placement means when printing on each of the different second sides. [Figure 13] 2A to 2C are schematic diagrams showing examples of the configuration of an ink tank, an ink supply path, an ink discharge path, and a print head.

[0016] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

[0017] Fig. 1 is a schematic perspective view showing an example of the configuration of an inkjet recording apparatus according to this embodiment, Fig. 2 is a schematic front view showing an example of the configuration of an inkjet recording apparatus according to this embodiment, and Fig. 3 is a schematic side view showing an example of the configuration of a carriage and its surroundings. Below, an overview of the inkjet recording apparatus according to this embodiment will be described with reference to Figs. 1 to 3.

[0018] An outline of a configuration example of the inkjet recording apparatus 1 shown in FIGS. 1 to 3 is as follows.

[0019] First, a recording head 12 having a nozzle face in which nozzles for ejecting ink onto the outer surface of a recording medium 18 are arranged in a nozzle row direction in a predetermined direction, and an actinic ray irradiation device 13 for irradiating the ink that has landed on the outer surface of the recording medium 18 with actinic ray are mounted on a carriage 11. The carriage 11 is mounted below a carriage holding part 16. Also, above the carriage 11, an ink tank 14 for holding ink and an ink supply path 15 for connecting the ink tank 14 and the recording head 12 and supplying ink to the recording head 12 are arranged. Furthermore, below the carriage 11, a mounting means 17 for mounting and fixing the recording medium 18 on a mounting surface is arranged.

[0020] An X-axis moving means 21 is connected to the carriage holding unit 16 for moving the carriage 11 in the X direction, which is a direction substantially parallel to the placement surface and substantially perpendicular to the nozzle row direction. A Y-axis driving means 22 is connected to the placement means 17 for moving the placement means 17 in the Y direction, which is substantially parallel to the placement surface and substantially perpendicular to the X direction. A Z-axis driving means 23 is connected to the carriage holding unit 16 for moving the carriage in the Z direction, which is a direction substantially perpendicular to the X and Y directions.

[0021] The carriage holding unit 16 is further connected to an α-axis driving means 24 for rotating the carriage 11 about a rotation axis (α-axis) extending in a direction intersecting the nozzle row direction in an α-direction (arrow direction shown in Figs. 1 and 3) that describes an arcuate trajectory intersecting the Y direction so that the nozzle surface of the recording head 12 faces from the first surface to the second surface and the third surface, respectively, thereby changing the orientation of the nozzle surface of the recording head 12 mounted on the carriage 11. In addition, a θ-axis driving means 25 for rotating the mounting means 17 in a rotation direction (θ direction) about a rotation axis (θ-axis) extending in a direction perpendicular to the mounting surface is connected to the mounting means 17.

[0022] Further, near one end in the X direction (the right side in the example shown in Figs. 1 and 2), there is provided a retract position 20 for retracting the carriage 11 from near the mounting means 17. Usually, the carriage 11 is moved to the retract position 20 by driving the X-axis driving means 21, and at the retract position, various necessary operations can be performed, such as maintenance operations such as ink purging and wiping of the recording head 12, and driving each of the Y-axis driving means 22, the Z-axis driving means 23, the α-axis driving means 24, and the θ-axis driving means 25. The retract position 20 may be located on the left side or in another appropriate position depending on the device configuration.

[0023] The details of each part will be explained below.

[0024] The recording head 12 has an ink flow path that communicates with an ink supply port and a nozzle (not shown), and further has a nozzle surface in which a plurality of nozzles for ejecting ink are arranged in a predetermined nozzle row direction, and an image is recorded by ejecting ink from the nozzles onto a recording medium 18 according to image data. Inkjet recording devices for recording color images usually have a plurality of recording heads 12 for ejecting ink of four colors, black (K), cyan (C), magenta (M), and yellow (Y), mounted at predetermined intervals in a direction approximately perpendicular to the nozzle row direction. In addition, if necessary, it is possible to further mount a recording head 12 for ejecting special color inks such as white (W) and clear (CL) required for required image formation, or to omit the recording heads 12 corresponding to colors that are not required. Furthermore, as the recording head 12, a recording head 12 capable of ejecting ink of one color may be used, or a recording head 12 capable of ejecting ink of two or more different colors (a recording head compatible with multi-color ink) may be used. In addition, by arranging the recording heads 12 in the nozzle row direction, it is possible to increase the width of the image that can be recorded at one time in the nozzle row direction. In the inkjet recording device according to this embodiment, four recording heads 12 corresponding to four colors of ink, black (K), cyan (C), magenta (M), and yellow (Y), are mounted on the carriage 11.

[0025] When the ink used for image recording is actinic radiation curable ink, the carriage 11 is further equipped with an actinic radiation irradiation device 13. The actinic radiation irradiation device 13 may be an ultraviolet radiation irradiation device, an electron beam device, or the like, which may be appropriately selected depending on the properties of the actinic radiation curable ink used. In this embodiment, an ultraviolet radiation irradiation device is used correspondingly to the use of ultraviolet radiation curable ink. In addition, the lamp used in the ultraviolet radiation irradiation device may be of an appropriate type, such as mercury, metal halide, or LED. When the ink used for image recording is not an actinic radiation curable ink, such as a solvent-based ink or a water-based ink, the actinic radiation irradiation device 13 may be omitted, or various heat drying devices may be appropriately arranged instead. Hereinafter, a description of the actinic radiation irradiation process by the actinic radiation irradiation device 13 will be omitted, but when an actinic radiation curable ink is used, the actinic radiation irradiation process by the actinic radiation irradiation device 13 is performed as necessary after the image recording operation described below.

[0026] The ink tanks 14 are usually arranged in a number corresponding to each type of ink used in the inkjet recording device 1. The ink tank 14 contains ink and a space above the ink liquid surface, and a pressure adjustment port (not shown) communicates with this space. During printing, the pressure in the space in the ink tank 14 is maintained at a negative pressure, so that ink does not leak from the nozzles of the recording head 12 and a meniscus shape suitable for ejecting ink is maintained at the nozzle opening. When a cleaning operation of the recording head 12 is performed, the pressure in the space in the ink tank 14 is switched to a positive pressure or atmospheric pressure to forcibly discharge ink from the nozzles of the recording head 12. The configuration of the ink tank 14 is not limited to the above, and it is possible to select another configuration that can appropriately perform control such as maintaining the meniscus shape of the ink at the nozzle opening.

[0027] The ink tank 14 and the recording head 12 are connected via an ink supply path 15, and ink is supplied from the ink tank 14 to the recording head 12. The ink supply path 15 is made of a resin tube having appropriate flexibility and flexibility suitable for piping. The shape of the ink supply path 15 can be selected as appropriate, but in this embodiment, a spiral-shaped pipe is used. In the inkjet recording device 1 in this embodiment, as described later, the direction of the recording head 12 can be changed by rotating the carriage 11. At this time, the distance between the ink tank 14 and the recording head 12 changes, so the ink supply path 15 needs to be configured so that its length is sufficient even when this distance is increased. However, if the ink supply path 15 is simply made longer, the ink supply path 15 may be bent when the distance between the ink tank 14 and the recording head 12 becomes closer, which may cause pressure fluctuations in the ink supply path 15 due to a sudden change in the cross-sectional area of ​​the inner diameter of the ink supply path 15. Furthermore, if the ink supply path 15 is bent, when the carriage 11 is moved in the X direction by the driving of the X-axis driving means 21, the bent portion is strongly affected by the G force in the X direction, and pressure fluctuations may occur in the ink supply path 15. These pressure fluctuations affect the ink meniscus shape of the nozzle opening of the recording head 12, deteriorate the ink ejection stability, and cause deterioration of the print image quality. Therefore, in this embodiment, the ink supply path 15 is made into a spiral shape, which makes it easy to expand and contract, thereby reducing the risk of the above-mentioned pressure fluctuations. Of course, it is also possible to assume a configuration in which the installation position of the ink tank 14 is moved according to the change in the distance between the ink tank 14 and the recording head 12 to follow it, and it is also possible to assume a configuration in which the shape of the ink supply path 15 is easy to expand and contract.

[0028] FIG. 13 is a schematic diagram showing an example of the configuration of an ink tank, an ink supply path, an ink discharge path, and a recording head. In order to maintain the meniscus shape of the ink at the nozzle opening of the recording head 12, in order to stabilize the water pressure of the ink flow path (not shown) of the recording head 12, a configuration is also assumed in which the ink discharge port of the recording head 12 and the space filled with negative pressure above the ink contained in the ink tank 14 are connected by an ink discharge path 19 pipe. In this case, a spiral-shaped pipe can be used for the ink discharge path 19 as in the case of the ink supply path 15. Furthermore, in this case, as shown in FIG. 13, a configuration can be adopted in which the ink supply path 15 and the ink discharge path 19 are made into a spiral shape, and the spiral parts are further combined and connected in two parts above and below, and branched on the way. With this configuration, even if multiple pipes are arranged, tangling due to interference between the spiral parts can be eliminated, and maintenance can be improved, such as the ease of attaching and detaching the ink supply path 15 and the ink discharge port 19.

[0029] The X-axis driving means 21, the Y-axis driving means 22, and the Z-axis driving means 23 use linear motors, which are driving systems that move linearly. The recording medium 18 in this embodiment has a three-dimensional shape, and images are recorded on multiple surfaces of the recording medium 18. However, if a robot arm is used, there are concerns that the cost will be high and the accuracy of the moving speed between two points will be relatively non-uniform. In particular, in an inkjet recording device, since ink is discharged from the recording head 12 during movement between two points to record an image, the accuracy of the moving speed between two points is important. Therefore, in this embodiment, a linear motor is used, which is less expensive than a robot arm and has excellent uniformity in the accuracy of the moving speed between two points. As the type of linear motor, a linear motor, a ball screw, a timing belt, or other suitable type can be selected.

[0030] The carriage 11 is formed in a configuration suitable for appropriately arranging the recording head 12, the active light irradiation device 13, and the like. The carriage 11 is held by the carriage holding unit 16 via the α-axis driving means 24 as shown in FIG. 3. As described above, in order to perform image recording on the three-dimensional recording medium 18, the recording head 12 mounted on the carriage 11 is rotated in the above-mentioned α direction by the rotational drive of the α-axis driving means 24, and the nozzle surface is appropriately opposed to each of the recording surfaces of the recording medium 18. A rotary motor suitable for rotating the carriage 11 and holding it at an arbitrary position is applied to the α-axis driving means 24. As the type of rotary motor, an appropriate one can be selected, such as a stepping motor or a servo motor.

[0031] Here, the α-axis driving means 24 is preferably disposed so that the center of rotation of the recording head 12 is approximately the center of the nozzle row in the nozzle row direction, and at a position as close as possible to the nozzle face and does not protrude from the nozzle face to contact the recording medium 18, i.e., on the opposite side of the nozzle face in the ink ejection direction. By doing so, it is possible to minimize the head difference in the ink flow path in the recording head 12 when the recording head 12 is rotated, and it is possible to prevent the collapse of the meniscus shape of the ink at the nozzle opening and ensure stable ink ejection.

[0032] The mounting means 17 can be selected from a suitable fixing jig according to the shape of the recording medium 18, such as a vacuum suction table, a magnet, an electrostatic chuck, an arm, etc., suitable for mounting and fixing the recording medium 18. In this embodiment, a vacuum suction table is used. In the inkjet recording device 1 in this embodiment, the mounting means 17 is connected to a θ-axis driving means 25 that rotates the mounting means 17 in the θ direction around the θ-axis perpendicular to the mounting surface. This allows image recording to be performed on each of the multiple second surfaces by rotating the mounting means 17 itself without manually changing the orientation in which the recording medium 18 is placed. The θ-axis driving means 25 may be omitted if printing on the multiple second recording surfaces can be handled by manually changing the orientation in which the recording medium 18 is placed.

[0033] 4 is a schematic diagram showing an example of the shape of the recording medium. As the recording medium 18, media having various three-dimensional shapes can be selected.

[0034] For example, as shown in Fig. 4(a), the recording medium 18 may be a thick board having an end grain. In this case, the top surface is set as the first surface, the four sides of the end grain surface are set as the second surface, and the bottom surface opposite the top surface is designated as the third surface, and an image recording operation is performed on each surface by a printing sequence described later, thereby recording an image on each of the intended outer surfaces. Also, as shown in Fig. 4(b), even if the cross section of the second surface of the end grain surface has a shape with a convex portion composed of straight lines of many triangular or polygonal planes and the second surface is divided into multiple surfaces, image recording can be performed on each surface.

[0035] Also, as shown in Fig. 4(c), the recording medium 18 may be a plate-shaped recording medium in which the second surface of the butt end has a curved surface in the shape of an arc. As shown in the enlarged view of Fig. 4(c), the recording medium 18 may have a different radius R of the curved surface in the shape of an arc. Furthermore, as shown in Fig. 4(d), an image can be recorded even with a shape in which the second surface has a curved surface in the shape of an arc at the upper and lower ends, and the ends of the curved surface at the upper and lower ends are connected by straight lines.

[0036] Also, as shown in FIG. 4(e), the recording medium 18 may have four corners of the second surfaces curved, or as shown in FIG. 4(f), the recording medium 18 may have a complex shape with the entire outer surface being composed of multiple curved surfaces. In this case, a predetermined area of ​​the outer surface of the recording medium 18 may be divided and set as a first surface, a second surface, and a third surface. In the case of FIG. 4(e) and FIG. 4(f), the first surface, the second surface, and the third surface may be arbitrarily specified according to the shape of the recording medium 18 as relative surfaces that are set for convenience in order to specify the surface on which an image should be recorded in the inkjet recording device 1. In the following description, an example will be described in which the first surface is set as the top surface of the recording medium 18, the second surface is set as the end surface (side surface) of the recording medium 18, and the third surface is set as the back surface of the recording medium 18. In addition, when performing image recording on the third surface, the third surface needs to be placed on the mounting means 17 so that the portion on which image recording is to be performed extends beyond the mounting surface of the mounting means 17 and only a specified partial area is exposed.

[0037] 5 is a block diagram showing an example of the hardware configuration of the inkjet recording device according to this embodiment. The inkjet recording device 1 according to this embodiment is mainly controlled by a control computer 31. The recording head 12 ejects ink according to any image data under the control of a control board 32 and in response to a command from the control computer 31, and the actinic ray irradiation device 13 irradiates actinic rays in response to a command from the control computer 31 via a control driver 39. The X-axis driving means 21, the Y-axis driving means 22, the Z-axis driving means 23, the α-axis driving means 24, and the θ-axis driving means 25 are driven by the control of a controller 33 and via corresponding drivers 34, 35, 36, 37, and 38 in response to a command from the control computer 31.

[0038] Next, an overview of the image recording operation by the inkjet recording device 1 according to this embodiment will be described. The inkjet recording device 1 can record an image by either a single pass method or a multi-pass method. The single pass method is an image recording method in which the ejection of ink required to record an image on a predetermined unit area on the outer surface of the recording medium is completed in one image recording operation, thereby completing the recording of the image. The multi-pass method is an image recording method in which the ejection of ink required to record an image on a predetermined unit area on the outer surface of the recording medium is divided into multiple image recording operations (the number of times is called the number of passes), and the recording of the image on the predetermined unit area is completed by the multiple image recording operations. In either method, an operation of ejecting ink from the recording head onto the unit area to record an image and a feeding operation of moving the nozzle surface of the recording head 12 so as to face the next unit area are alternately performed until the recording of the predetermined image is completed on the entire surface to be recorded.

[0039] 6 is a schematic diagram for explaining an example of the operation of the carriage when printing on each of the first, second and third sides. In FIG. 6, an example will be explained using a plate-shaped recording medium 18.

[0040] FIG. 6(a) shows the orientation of the carriage 11 when printing is performed on the first side of the recording medium 18. When printing on the first side, as shown in FIG. 6(a), the carriage 11 is driven by the α-axis driving means 24 so that the nozzle surface of the recording head 12 faces the first side, and ink is ejected from the nozzles of the recording head 12 vertically downward to perform image recording on the first side facing vertically upward. In the case of an example of the inkjet recording device 1 according to the present embodiment, an image recording operation is performed in which the carriage 11 is moved in the X direction by the driving of the X-axis driving means 21 while ejecting ink from the nozzles of the recording head 12 to land on the first side to form an image according to the width of the nozzle row of the recording head 12 on the first side, and after this image recording operation, a feeding operation is performed in which the mounting means 17 is moved in the Y direction by the driving of the Y-axis driving means 22 to move the recording medium 18 in the Y direction, and each of these operations is performed a number of times according to the image data to be printed, thereby completing image recording on the first side.

[0041] FIG. 6B shows the orientation of the carriage 11 when printing is performed on the second side of the recording medium 18. When printing on the second side, as shown in FIG. 6B, the carriage 11 is oriented such that the nozzle surface of the recording head 12 faces the second side by driving the α-axis driving means 24, and image recording is performed on the second side facing the horizontal direction by ejecting ink from the nozzles of the recording head 12 in the horizontal direction. In the case of an example of the inkjet recording device 1 according to the present embodiment, an image recording operation is performed in which the carriage 11 is moved in the X direction by driving the X-axis driving means 21 while ejecting ink from the nozzles of the recording head 12 to land on the second side and form an image on the second side according to the width of the nozzle row of the recording head 12, and a feed operation is performed in which the recording head 12 is moved in the Z direction (which can be from above to below or from below to above) by driving the Z-axis driving means 23 after this image recording operation, by performing each of these operations a number of times according to the image data to be printed, thereby completing image recording on the second side.

[0042] FIG. 6(c) shows the orientation of the carriage 11 when printing is performed on the third surface of the recording medium 18. When printing on the third surface, as shown in FIG. 6(c), the carriage 11 is driven by the α-axis driving means 24 so that the nozzle surface of the recording head 12 faces the third surface, and ink is ejected from the nozzles of the recording head 12 from below in the vertical direction to above, thereby performing image recording on the third surface facing vertically downward. In the example of the inkjet recording device 1 according to the present embodiment, the carriage 11 is moved in the X direction by the drive of the X-axis driving means 21, while the nozzles of the recording head 12 are ejected and landed on the third surface to form an image according to the width of the nozzle row of the recording head 12 on the third surface, and after this image recording operation, the placement means 17 is moved in the Y direction by the drive of the Y-axis driving means 22 to move the recording medium 18 in the Y direction, and the image recording on the third surface is completed by performing each of the following operations a number of times according to the image data to be printed.

[0043] As described above, in the inkjet recording device 1 according to the present embodiment, the outer surface of the recording medium 18 facing the nozzle surface of the recording head 12 is switched to the first surface, the second surface, or the third surface depending on the surface on which an image is to be recorded by driving the α-axis driving means 24, and the driving means used for the feeding operation of the recording medium 18 is switched to the Y-axis driving means 22 or the Z-axis driving means 23 depending on the surface on which an image is to be recorded, so that an image can be recorded on any of the first surface to the third surface with a relatively simple device configuration by one inkjet recording device 1. Note that when the outer surfaces on which an image is to be recorded are only the first and second surfaces, or only the first and third surfaces, or only the second and third surfaces, or when there are surfaces on which an image does not need to be recorded, it is only necessary to execute, among the above operations, the operations necessary for recording an image on the necessary surfaces.

[0044] Hereinafter, examples of sequences for performing image recording on each of the first, second, and third sides will be described with reference to Figures 7 to 9. These sequences are executed by commands from the control PC 31 based on programs corresponding to the flowcharts in Figures 7 to 9. Note that the sequences are merely examples, and it is understood that additions, modifications, and omissions can be made as appropriate within the scope of the present invention.

[0045] First, a flow for recording an image on the first surface will be described. FIG. 7 is a flow chart showing an example of a sequence for printing the first surface of a recording medium by the inkjet recording device according to this embodiment. First, in step 71, the carriage 11 is moved to the retracted position 20 and retracted, and the α-axis driving means 24 is driven via the driver 37 under the control of the controller 33 receiving a command from the control PC 31 to rotate the carriage 11 so that the nozzle surface of the recording head 12 faces the first surface, and the state is set so that an image can be recorded (the state shown in FIG. 6(a) in this embodiment). If the nozzle surface of the recording head 12 is already in a state facing the first surface, step 71 can be omitted and the process can start from step 72.

[0046] Thereafter, in step 72, the X-axis driving means 21 is driven via the driver 34 under the control of the controller 33 which has received commands from the control computer 31 to move the carriage 11 in the X-direction, and the recording head 12 is operated via the control board 32 under commands from the control computer 31 according to the image data stored in the control computer 31, so that the nozzle surface of the recording head 12 ejects ink vertically from above downward from nozzles which are oriented so as to be able to eject ink vertically from above downward, as shown in FIG. 6(a), thereby performing an image recording operation for recording an image on a predetermined unit area of ​​the first surface.

[0047] Thereafter, in step 73, the Y-axis driving means 22 is driven via the driver 35 under the control of the controller 33 which receives a command from the control computer 31 to move the mounting means 17 in the Y direction, thereby moving the recording medium 18 a predetermined distance from upstream to downstream in the Y direction, and a feed operation is performed to move the nozzle surface of the recording head 12 to a position where image recording can be performed on the next unit area on the first side. When image recording is performed on the first side, the Y-axis driving means 22 is driven to perform the feed operation, so that the recording medium 18 can be efficiently transported and the next image recording operation can be started.

[0048] Thereafter, in step 74, it is determined whether or not the formation of the intended image on the first side has been completed, and if not, the process returns to step 72 again and repeats up to step 74. Then, when the formation of all the intended images has been completed, the flow shown in FIG. 7 ends, and the image formation on the first side is completed.

[0049] Next, a flow for recording an image on the second surface will be described. FIG. 8 is a flow chart showing an example of a sequence for printing the second surface of a recording medium by the inkjet recording device according to this embodiment. First, in step 81, the carriage 11 is moved to the retracted position 20 and retracted, and the α-axis driving means 24 is driven via the driver 37 under the control of the controller 33 receiving a command from the control PC 31 to rotate the carriage 11 so that the nozzle surface of the recording head 12 faces the second surface and is in a state where an image can be recorded (the state shown in FIG. 6(b) in this embodiment). If the nozzle surface of the recording head 12 is already in a state where it faces the second surface, step 81 can be omitted and the process can start from step 82.

[0050] Thereafter, in step 82, the X-axis driving means 21 is driven via the driver 34 under the control of the controller 33 which has received commands from the control computer 31 to move the carriage 11 in the X-direction, and the recording head 12 is operated via the control board 32 under commands from the control computer 31 according to the image data stored in the control computer 31, so that the nozzle surface of the recording head 12 ejects ink in a substantially horizontal direction from nozzles which are oriented so as to be able to eject ink in a substantially horizontal direction, as shown in FIG. 6(b), thereby performing an image recording operation for recording an image on a predetermined unit area of ​​the second surface.

[0051] Thereafter, in step 83, the Z-axis driving means 23 is driven via the driver 36 under the control of the controller 33 that receives a command from the control computer 31, and the carriage 11 facing the second surface (the nozzle surface of the recording head 12 is oriented so that ink can be ejected in a substantially horizontal direction as shown in FIG. 6(b)) is moved in the Z direction, thereby moving the recording head 12 a predetermined distance in the Z direction, and performing a feed operation to move the nozzle surface of the recording head 12 to a position where image recording can be performed for the next unit area on the second surface. The feed operation in the Z direction can be performed from above to below, or from below to above. In this way, when performing image recording on the second surface, unlike image recording on the first surface, the drive means used for the feed operation is switched from the Y-axis driving means 22 to the Z-axis driving means 23, and the recording head 12 and the recording medium 18 can be moved relatively efficiently to record an image on the second surface.

[0052] Thereafter, in step 84, it is determined whether or not the formation of the intended image on the second side has been completed, and if not, the process returns to step 82 again and repeats up to step 84. Then, when the formation of all the intended images has been completed, the flow shown in FIG. 8 ends, and the image formation on the second side is completed.

[0053] In addition, as shown in Figure 4 (b), in the case where the second surface is composed of multiple straight planes, such as when there is a convex portion with a triangular cross section, this flow is further carried out, and after image recording on one of the straight planes that constitute the second surface is completed, step 81 is further carried out to drive the α-axis driving means 24 and rotate the carriage 11 to face the nozzle surface of the recording head 12 to the further second surface, and then flow 82 and subsequent steps are carried out to perform image recording.

[0054] Next, a flow for recording an image on the third surface will be described. FIG. 9 is a flow chart showing an example of a sequence for printing the third surface of a recording medium by the inkjet recording device according to this embodiment. First, in step 91, the carriage 11 is moved to the retracted position 20 and retracted, and the α-axis driving means 24 is driven via the driver 37 under the control of the controller 33 which receives a command from the control PC 31, and the carriage 11 is rotated to make the nozzle surface of the recording head 12 face the third surface, and the state in which an image can be recorded (the state shown in FIG. 6(c) in this embodiment) is achieved. If the nozzle surface of the recording head 12 is already in a state in which it faces the third surface, step 91 can be omitted and the process can start from step 92.

[0055] Thereafter, in step 92, the X-axis driving means 21 is driven via the driver 34 under the control of the controller 33 which receives commands from the control computer 31 to move the carriage 11 in the X-direction, and the recording head 12 is operated via the control board 32 under commands from the control computer 31 according to the image data stored in the control computer 31, so that the nozzle surface of the recording head 12 ejects ink from the nozzles oriented so as to be able to eject ink from the lower to the upper direction in the vertical direction, as shown in FIG. 6(c), thereby performing an image recording operation for recording an image on a predetermined unit area of ​​the third surface.

[0056] Thereafter, in step 93, the Y-axis driving means 22 is driven via the driver 35 under the control of the controller 33 which receives a command from the control computer 31, and the carriage 11 facing the third surface (the nozzle surface of the recording head 12 facing so that ink can be ejected vertically from below to above as in FIG. 6(c)) is moved in the Y direction, thereby moving the recording medium 18 a predetermined distance in the Y direction, and performing a feed operation to move the nozzle surface of the recording head 12 to a position where image recording can be performed for the next unit area on the third surface. In this way, when performing image recording on the third surface, unlike image recording on the second surface, by switching again the axis used for the feed operation from the Z-axis driving means 23 to the Y-axis driving means 22, it is possible to efficiently move the recording head 12 and the recording medium 18 and record an image on the third surface.

[0057] Thereafter, in step 94, it is determined whether or not the formation of the intended image on the third side has been completed, and if not, the process returns to step 92 again and repeats up to step 94. Then, when the formation of all the intended images has been completed, the flow shown in Fig. 9 ends, and the image formation on the third side is completed.

[0058] By appropriately combining and implementing the three flows described above, it was possible to perform the intended image recording on all of the first to third sides of the recording medium 18 using the inkjet recording device 1 with a simple device configuration.

[0059] The above is a basic example of image recording by the inkjet recording apparatus 1 according to this embodiment. Next, image recording in the case where the second surface is curved as in FIGS. 4(c) and 4(d) will be described.

[0060] FIG. 10 is a schematic diagram showing an example of the operation of the carriage when the second surface has a curved surface. In this embodiment, as shown in FIG. 4(c), the second surface of the recording medium has a curved surface in a semi-cylindrical convex shape with a vertex in a predetermined direction. This three-dimensional recording medium is placed on the placement means 17 so that the predetermined direction is parallel to the Y axis, and recording is performed on the second surface. When the second surface has a curved surface as shown in FIG. 10, if the nozzle surface of the recording head 12 is simply directed horizontally, ink is ejected approximately horizontally, and the feed operation is performed by driving the Z axis as in the flow described in FIG. 8, the distance between the end of the curved surface and the nozzle surface becomes large, leading to deterioration of image quality at the ends of the second surface (the upper and lower ends in the example of FIG. 10). Therefore, as shown in Figure 10, the second surface is divided into any number of recording sections, and for each image recording in a recording section, the carriage 11 is rotated by driving the α-axis driving means 24 to face each recording section in sequence, and a feeding operation is performed by combining the driving of one or both of the Y-axis driving means 22 and the Z-axis driving means 23.This makes it possible to efficiently record images on a curved second surface with a simple device configuration while maintaining the distance between the second surface and the nozzle surface within a specified range.

[0061] In this embodiment, the Y-axis driving means 22 and the Z-axis driving means 23 are driven in the following combination. That is, when the recording section does not include the apex of the second surface and is located above the apex in the Z direction, as shown in Figures 10(a) and 10(b), the Y-axis driving means 22 is driven to move the carriage 11 in the Y direction and away from the second surface, and the Z-axis driving means 23 is driven to move the carriage 11 downward in the Z direction and toward the second surface. Also, when the recording section includes the apex of the second surface, as shown in Figure 10(c), only the Z-axis driving means 23 is driven to move the carriage 11 downward in the Z direction. Also, when the recording section does not include the apex of the second surface and is located below the apex in the Z direction, as shown in Fig. 10(d) and (e), the Z-axis driving means 23 is driven to move the carriage 11 downward in the Z direction and away from the second surface, and the Y-axis driving means 22 is driven to move the carriage 11 in the Y direction and toward the second surface. In this way, by combining the Y-axis driving means 22 and the Z-axis driving means 23 according to the facing state of the nozzle surface and the second surface, it is possible to maintain the distance between the nozzle surface and the second surface while avoiding contact between the nozzle surface and the second surface, and to realize the feed operation. Note that the Y-axis driving means 22 and the Z-axis driving means 23 may be driven in an appropriate order with the second surface and the nozzle surface facing each other, but it is necessary to avoid contact between the second surface and the nozzle surface to prevent damage to the nozzle surface. Therefore, by moving the carriage 11 to the retracted position 20 and then driving the Y-axis drive means 22 and the Z-axis drive means 23, the order in which the Y-axis drive means 22 and the Z-axis drive means 23 are driven is not important, and the carriage 11 can be moved reliably and quickly to a safe position.

[0062] The method of setting the recording section and the feeding operation of the recording medium 18 are arbitrarily set according to the shape of the second surface. For example, it is assumed that they will be set by the following method.

[0063] The number of divisions N (≧2) of the recording section is set by inputting an arbitrary integer according to the required image quality and required recording speed in the control computer 31. Normally, the more the number of divisions, the more uniform the distance between the second surface and the nozzle surface can be maintained, leading to improved image quality, but the number of times the α-axis driving means 24 is driven increases accordingly, resulting in a slower recording speed.

[0064] The necessity for driving the Y-axis driving means 22 and the Z-axis driving means 23 and the amount of drive (the amount of movement of the carriage 11) are specified by grasping the shape information of the curved surfaces and straight lines that constitute the second surface, and then inputting any numerical values ​​for specifying the shape into the control computer 31. The shape numerical values ​​of the second surface for this purpose can be grasped by any method, but the following method is assumed, for example.

[0065] First, in the case of the second surface having the shape shown in Fig. 4(c), the thickness t of the recording medium 18 and the radius R of the arc of the curved portion are grasped as shape information of the recording medium 18. By grasping R and t, t becomes the chord of the curved circle of radius R that constitutes the second surface, and the circumference that constitutes the second surface can be obtained, and the shape of the second surface can be grasped numerically. Then, in accordance with this shape, the Y-axis drive means and the Z-axis drive means are driven so that the distance between the nozzle surface of the recording head 12 and the second surface becomes a predetermined value.

[0066] 4(d), when the second surface is composed of a plurality of arc-shaped curved surfaces and straight surfaces, the thickness t of the recording medium 18, the radii R1 and R2 of the arcs of the curved surface, and the length t2 of the surfaces that compose the straight surface are grasped as shape information of the recording medium 18. This makes it possible to grasp the degree of curvature of the arc-shaped curved surfaces that compose the second surface numerically. Then, in accordance with this shape, the Y-axis driving means 22 and the Z-axis driving means 23 are driven so that the distance between the nozzle surface of the recording head 12 and the second surface becomes a predetermined numerical value.

[0067] In this way, the numerical values ​​specifying the shape of the second surface are input into the control computer 31, and then the program stored in the control computer 31 calculates the feed amount of the carriage 11 in the Y and Z directions due to the feed operation, the number of recording sections (N), and the combination of the Y-axis drive means 22 and the Z-axis drive means 23.

[0068] The sequence of operations for image recording in the case where the second surface is curved as described above will be described with reference to Fig. 11. Fig. 11 is a flow chart showing an example of a sequence for printing on the second surface by the inkjet recording device according to this embodiment when the second surface of the recording medium has a curved surface.

[0069] First, in step 1101, the recording sections are set. Necessary information such as the above-mentioned information on the number of divisions and information on the shape of the second surface of the recording medium 18 is input into a program stored in the control personal computer 31, and multiple (N) recording sections are set according to the input information, and settings such as the drive of the α-axis driving means 24 and the selection of the feed operation (selection of a combination of drives of the Y-axis driving means 22 and the Z-axis driving means 23) corresponding to each recording section are performed in advance.

[0070] Next, in step 1102, image recording is started in one of the recording sections, M (N≧M≧1).

[0071] After starting image recording in one of the recording sections in step 1102, the positions of the carriage 11 with respect to the α-axis, Z-axis, and Y-axis are calculated in step 1103, and in the subsequent steps, it is determined whether or not each driving means needs to be driven.

[0072] Next, in step 1104, it is determined whether or not it is necessary to drive the α-axis driving means 24. If it is determined that it is necessary, the process proceeds to step 1105, and if it is determined that it is not necessary, step 1105 is omitted and the process proceeds to step 1106.

[0073] If it is determined in step 1104 that it is necessary to drive the α-axis driving means 24, in 1105, the α-axis driving means 24 is driven via the driver 37 under the control of the controller 33 which receives commands from the control computer 31, and the carriage 11 is rotated to position the nozzle surface of the recording head 12 facing the recording section where image recording of the second surface is performed.

[0074] Next, in step 1106, it is determined whether or not it is necessary to drive the Y-axis driving means 22. If it is determined that it is necessary, the process proceeds to step 1107, and if it is determined that it is not necessary, step 1107 is omitted and the process proceeds to step 1108.

[0075] If it is determined in step 1106 that it is necessary to drive the Y-axis driving means 22, in step 1107, the controller 33 receives commands from the control computer and drives the Y-axis driving means 22 via the driver 35 to move the carriage 11 in the Y direction.

[0076] Next, in step 1108, it is determined whether or not it is necessary to drive the Z-axis driving means 23. If it is determined that it is necessary, the process proceeds to step 1109, and if it is determined that it is not necessary, step 1109 is omitted and the process proceeds to step 1110.

[0077] If it is determined in step 1108 that it is necessary to drive the Z-axis driving means 23, in step 1109, the controller 33 receives commands from the control computer and drives the Z-axis driving means 23 via the driver 36 to move the carriage 11 in the Z direction.

[0078] Then, in step 1110, the carriage 11 is moved in the X direction by driving the X-axis driving means 21 via the driver 34 under the control of the controller 33 which has received instructions from the control computer, and the recording head 12 is operated via the control board 32 under instructions from the control computer 31 according to the image data stored in the control computer 31, and ink is ejected from the nozzles of the recording head 12, thereby performing an image recording operation for recording an image on a specified unit area on the second surface.

[0079] Thereafter, in step 1111, it is determined whether the desired image recording has been completed on the entire second side, and if No, the process returns to step 1102 to perform image recording operation for the next recording section (M+1). If Yes, all steps in this flow are completed.

[0080] In addition, when image recording is performed on a plurality of second surfaces, an example as shown in FIG. 12 is assumed. FIG. 12 is a schematic diagram for explaining an example of the operation of the carriage and the mounting means when printing each of the different second surfaces, and is a schematic diagram of the inkjet recording device 1 according to the present embodiment as viewed from above. As shown in FIG. 12(a) to FIG. 12(c), after image recording on one of the second surfaces is completed, the mounting means 17 on which the recording medium 18 is mounted is rotated by the θ-axis driving means 25 around a rotation axis passing through the center of the mounting means 17 as viewed from above in the Z direction, thereby rotating the recording medium 18 and causing the nozzle surface of the recording head 12 to face another second surface, thereby sequentially recording images on each of the different second surfaces, and image recording can be performed over the entire circumference of all the second surfaces.

[0081] In the above description, in order to facilitate understanding of the present invention, descriptions of well-known technical matters have been omitted as appropriate.

[0082] Various embodiments and modifications are possible without departing from the broad spirit and scope of the present invention. The above-described embodiments are for the purpose of explaining the present invention and do not limit the scope of the present invention. That is, the scope of the present invention is indicated by the claims, not the embodiments. Various modifications made within the scope of the claims and within the scope of the meaning of the invention equivalent thereto are considered to be within the scope of the present invention. [Explanation of symbols]

[0083] 1 Inkjet recording device 11 Carriage 12 Recording head 13 Active ray irradiation device 14 Ink tank 15 Ink supply path 16 Carriage holder 17 Mounting means 18 Recording media 19 Ink discharge path 20 Evacuation position 21 X-axis drive means 22 Y-axis drive means 23 Z-axis drive means 24 α-axis drive means 25 θ-axis drive means

Claims

1. An inkjet recording apparatus for recording an image on a three-dimensional recording medium having at least a first surface and a second surface different from the first surface on its outer surface, a recording head having a nozzle surface on which a plurality of nozzles for ejecting ink onto the outer surface of the recording medium are arranged in a predetermined direction; a loading means for loading the recording medium; a rotating means for rotating the recording head about a rotation axis in a direction intersecting the predetermined direction to change the orientation of the nozzle surface; a first moving means for moving the recording head in a first direction intersecting the predetermined direction; a second moving means for moving the recording medium placed on the placement means in a second direction substantially perpendicular to the first direction; When an image is recorded on the first surface, a recording operation is performed in which ink is ejected from the nozzles and impacted on the first surface while the recording head is moved in the first direction by the first moving means with the nozzle surface and the first surface opposed to each other, and an operation is performed in which the recording medium placed on the placement means is moved in the second direction by the second moving means after the recording operation, a recording control means for executing a recording operation in which, when an image is recorded on the second surface, the recording head is rotated by the rotating means so that the nozzle surface faces the second surface, and the recording head is moved in the first direction by the first moving means, causing ink to be ejected from the nozzles and land on the second surface; and An inkjet recording apparatus comprising:

2. a third moving means for moving the recording head in a third direction substantially perpendicular to the first direction and the second direction, 2. The inkjet recording device according to claim 1, wherein, when the recording control means records an image on the second surface, the recording control means performs a recording operation in which the recording head is rotated by the rotating means so that the nozzle surface faces the second surface, and the recording head is moved in the first direction by the first moving means while ejecting ink from the nozzles to cause the ink to land on the second surface, and an operation in which the recording head is moved in the third direction by the third moving means.

3. a retreat area for preventing the nozzle surface of the recording head from facing an outer surface of the recording medium by driving the first moving means is disposed in the first direction, 3. The ink jet recording apparatus according to claim 1, wherein the rotation of the recording head by the rotation means is carried out when the recording head is positioned in the retraction area.

4. an ink tank for holding ink for supplying ink to the recording head is disposed at a predetermined distance from the recording head in a third direction substantially perpendicular to the first direction and the second direction, the recording head has an ink supply port for supplying ink to the nozzles; the ink tank and the ink supply port are in communication with each other through an ink supply path; the ink supply path has a first spiral portion; 3. The inkjet recording apparatus according to claim 1 or 2.

5. an ink tank for holding ink for supplying ink to the recording head is disposed at a predetermined distance from the recording head in a third direction substantially perpendicular to the first direction and the second direction, the recording head has an ink supply port for supplying ink to the nozzles; the ink tank and the ink supply port are in communication with each other through an ink supply path; the ink supply path has a first spiral portion; The inkjet recording apparatus according to claim 3 .

6. The recording head has an ink outlet for discharging ink, The ink tank further contains a negative pressure space, which is controlled to a negative pressure, above the ink stored therein in the vertical direction, the ink outlet and the negative pressure space contained in the ink tank are in communication with each other through an ink discharge path; the ink discharge path has a second spiral portion; The inkjet recording apparatus according to claim 4 , wherein the first spiral portion and the second spiral portion overlap each other to form a double shape.

7. The recording head has an ink outlet for discharging ink, The ink tank further contains a negative pressure space, which is controlled to a negative pressure, above the ink stored therein in the vertical direction, the ink outlet and the negative pressure space contained in the ink tank are in communication with each other through an ink discharge path; the ink discharge path has a second spiral portion; The inkjet recording apparatus according to claim 5 , wherein the first spiral portion and the second spiral portion overlap each other to form a double shape.

8. An inkjet recording device as described in claim 1 or claim 2, wherein the center of rotation of the recording head in the specified direction by the rotating means is positioned so that it is approximately in the center of the nozzle surface in the specified direction and faces the opposite side of the nozzle surface in the direction in which ink is ejected.

9. a mounting means rotating means for rotating the mounting means about an axis extending in a third direction substantially perpendicular to the first direction and the second direction, 3. An inkjet recording device according to claim 1, wherein, in an image recording operation on the second surfaces, after recording an image on one of the second surfaces, the placement means is rotated by the placement means rotation means to bring one of the further second surfaces into opposition to the nozzle surface, and an image recording operation on the further second surface is performed to record an image on the further second surface.

10. further, an actinic ray irradiation device having an irradiation surface for irradiating the recording medium with actinic rays is disposed at a predetermined distance from the recording head in the first direction, 3. The inkjet recording apparatus according to claim 1, wherein the irradiation surface faces either the first surface or the second surface in response to rotation of the rotation means.

11. The recording medium further has a third surface facing the first surface in an opposite direction, and is placed on the placement means in a state where a partial area of ​​the third surface of the recording medium is exposed, With the nozzle surface and the partial area of ​​the third surface facing each other, an image is recorded on the partial area by an operation of ejecting the ink from the nozzles and causing the ink to land on the partial area while moving the recording head in the first direction by the first moving means, and an operation of moving the recording medium fixed by the placement means in the second direction by the second moving means.

3. The inkjet recording apparatus according to claim 1 or 2.

Images