JP2008246855A - Printing method for three-dimensional surface - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printing method for three-dimensional surface which enables printing on the surface to be printed with high precision irrespective of the size of the matter to be printed. <P>SOLUTION: With the three-dimensional surface printing method, the matter to be printed (base material 11 of console lid) which the non-plane three-dimensional surface as the surface to be printed is targeted for printing, and the printed matter concerned is arranged under an ink head 27 in an ink-jet printer, and the ink injected downward from the nozzle group of the ink head 27 is adhered to the surface to be printed. When the ink is injected from the nozzle group, both of the ink head 27 and the matter to be printed are displaced, including the displacement due to the movement of the ink head 27 in the horizontal direction (X direction, Y direction), while keeping the distance from the nozzle group up to the surface to be printed (top face and side, etc. of base material 11) at nearly regularity. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for printing a three-dimensional surface such as a curved surface or a bent surface of an object to be printed using an inkjet printer.

  Some console lids, switch bases, center clusters, and the like, which are interior parts for vehicles, are decorated with a wood grain or the like on a synthetic resin base material. One of the methods for performing this decoration is a printing method using an ink jet printer. In this method, a plane is a printing surface, a printing material is disposed below an ink head in an ink jet printer, and ink is ejected downward from a nozzle group of the ink head to adhere the ink to the printing surface.

  According to this printing method, when the surface to be printed is a horizontal surface, the ink particles adhere to the surface to be printed without coming into contact with each other during scattering, and an intended pattern (pattern) is obtained. However, on the printing surface inclined with respect to the horizontal plane or the curved printing surface, the ink particles come into contact with each other during the scattering to form a color and adhere to the printing surface in this state. Therefore, the printed pattern (pattern) is blurred or blurred, and it is difficult to print a pattern (pattern) having the same quality as the horizontal printing surface. Note that blurring is a phenomenon in which attached ink particles are scattered and spread out, and blurring is a phenomenon in which color shades and borders become unclear.

  In many cases, the latter surface to be printed corresponds to the side surface of the material to be printed, but also the peripheral edge of the opening in the switch base or the like. That is, the switch base or the like is provided with an opening for incorporating the switch at a location different from the side surface (such as a central portion of the upper surface). A boundary portion between the wall surface of the opening and the upper surface, that is, a peripheral portion of the opening can also be a printing target. Since this part is also not a horizontal plane, printing is difficult for the same reason as described above.

On the other hand, for example, Patent Document 1 describes a method of printing on a curved surface. In this printing method, a robot configured to grip a substrate and be universally driven is used. Then, printing is performed by ejecting ink from the nozzle group of the ink head onto the printing surface of the printing material while moving the printing material gripped by the robot three-dimensionally.
JP-A-5-293955

  However, the printing method described in the above-mentioned patent document 1 is intended for printing exclusively on small objects such as shoes. Therefore, it is not suitable for printing on the printing surface of a large-sized printing material. That is, the printing method described in Patent Document 1 performs printing while changing the relative positional relationship between the nozzle group of the ink head and the printing surface only by driving the arm that grips the printing material in the robot. Therefore, when the printing material is small, the printing material can be accurately displaced at high speed. However, when the printing material is large, there is a limit in displacing the printing material at high speed with high accuracy. As a result, it becomes difficult to ensure the same printing accuracy as that of a small substrate.

  The present invention has been made in view of such circumstances, and the object thereof is to provide a three-dimensional surface printing method capable of printing on a printing surface with high accuracy regardless of the size of the printing material. Is to provide.

  In order to achieve the above object, according to the first aspect of the present invention, there is provided a printing object having a non-planar three-dimensional surface as a printing surface, and the printing object is below an ink head in an inkjet printer. The three-dimensional surface printing method is arranged to attach the ink ejected downward from the nozzle group of the ink head to the printing surface, and the ink is ejected from the nozzle group when the ink is ejected. The gist of the invention is that both the ink head and the substrate to be printed are displaced, including the horizontal movement of the ink head, while keeping the distance to the printing surface substantially constant.

  Here, the three-dimensional surface refers to a non-planar surface, for example, a curved surface, a bent surface, or the like. In addition, it is desirable that the distance from the nozzle group to the printing surface is maintained at a value in the range of 2 to 5 mm. This is because if the distance is 5 mm or more, the printed pattern may be blurred or blurred.

  According to the above printing method, when the printing surface of the printing material is wider than the area where ink can be ejected and adhered from the nozzle group, the nozzle group and the printing surface ( It is necessary to change the relative position to the substrate. In order to change the relative position, according to the first aspect of the present invention, when the ink is ejected, both the ink head and the printing material are displaced while the distance from the nozzle group to the printing surface is kept substantially constant. Therefore, as compared with the case where the ink head is fixed and only the printed material is displaced as in the invention described in Patent Document 1, the relative position can be changed by slowly displacing the printed material. Ink can be attached to the printing surface with high accuracy not only for small printing materials but also for large printing materials.

  According to a second aspect of the present invention, in the first aspect of the invention, the ink is an ultraviolet curable ink and irradiates the printed surface with ultraviolet rays when the ink is ejected onto the printed surface. This is the gist.

According to the above printing method, ultraviolet rays are irradiated almost simultaneously with the ejection of the ink, so that the ultraviolet curable ink attached to the printing surface is cured in a short time.
According to a third aspect of the present invention, in the first or second aspect of the present invention, the printed material is provided with an opening that opens in the printed surface, and the peripheral edge of the opening has a curvature. The gist is that it is formed in a curved surface having a radius of 2 mm or less.

  When the above printing method is applied to a printing material having an opening on the printing surface, there is a range in which a printed pattern (pattern) does not blur or blur with respect to the distance from the nozzle group to the printing surface. When the peripheral edge portion of the opening is formed by a curved surface, the distance from the nozzle group to the curved surface increases as the radius of curvature of the curved surface increases, and easily exceeds the above range.

  In response to this, it is conceivable that the substrate is inclined so that the distance is within the above range. However, when the curved surface is the peripheral edge of the opening that opens in the printing surface as described above, the printing surface exists at least around the opening. Therefore, if the substrate is tilted excessively, the substrate will interfere with the ink head that moves in the horizontal direction.

  In addition, when the printed surface is viewed from a direction orthogonal to the printed surface, as the curvature radius of the curved surface increases, the area to be visually observed becomes larger at the periphery, and the printing situation on the curved surface is conspicuous. It becomes easy.

  In this regard, it is effective to set the curvature radius of the curved surface to 2 mm or less as in the third aspect of the invention. In carrying out the printing method according to the first or second aspect of the invention described above, if the printed material having the curved surface is used as the peripheral portion of the opening, the appearance can be improved without inclining the printed surface with respect to the horizontal plane. Ink can be attached to the printing surface without damage.

  According to the three-dimensional surface printing method of the present invention, both the ink head and the printed material are displaced while keeping the distance from the nozzle group to the printed surface substantially constant. Thus, it becomes possible to perform printing on the printing surface with high accuracy.

Hereinafter, an embodiment in which the present invention is embodied in a method for printing a vehicle interior product will be described with reference to FIGS.
First, vehicle interior parts to which the printing method is applied will be described. This vehicle interior product is, among the interior products provided on the vehicle, (i) being relatively large, (ii) having an outer surface having a three-dimensional shape, and (iii) having a grain or the like on the outer surface. It satisfies the condition that it is decorated. Examples of vehicle interior products that satisfy these conditions (i) to (iii) include console lids (covers such as armrests and accessory compartments), armrest panels attached to doors, center console panels, and the like. Here, a console lid will be described as an example.

  About the said vehicle interior goods, the thing of the state before decorating (here printing) is given to an outer surface turns into a to-be-printed material. As shown in FIG. 3, in the case of a console lid, for example, a base material 11 molded by a synthetic resin is a substrate.

  In order to specify the direction in each figure including FIG. 3, the direction from the lower right to the upper left in FIG. 3 is referred to as the “X direction”, and the direction from the upper right to the lower left is referred to as the “Y direction”. The upper direction is referred to as the Z direction.

  The base material 11 has a small thickness in the Z direction (low height), and has a longer length in the X direction than in the Y direction. The upper surface 12 of the base material 11 is a convex curved surface that bulges slightly upward so that the height is the highest at the intermediate portion in the Y direction and the height decreases as the distance from the intermediate portion increases in the Y direction. On the other hand, the height of the upper surface 12 of the base material 11 is substantially uniform in the X direction. Moreover, the boundary part of the upper surface 12 of the base material 11 and the side surfaces 13 and 13 about the X direction is comprised by the convex curved surface 14 also about any side surface 13 and 13. FIG. Further, the boundary portion between the upper surface 12 and the side surfaces 15 and 15 in the Y direction is constituted by a convex curved surface 16 for each of the side surfaces 15 and 15. These upper surface 12, both side surfaces 13, 13 and both side surfaces 15, 15 correspond to the printing surface.

  Printing on the printing surface of the substrate 11 is performed in a state where the substrate 11 is mounted on the printing stand 17. The printing stand 17 is provided with a holding mechanism (not shown) that holds the base material 11 in a predetermined posture.

  Here, the printed surface of the base material 11 is wider than the area where ink can be ejected at once from the nozzle group of the ink head described later. Therefore, it is necessary to change the relative position between the nozzle group and the printing surface (printed material) while ejecting ink from the nozzle group. In order to change the relative position, the printing device 21 shown in FIGS. 1 and 2 is used.

  Next, the schematic configuration of the printing apparatus 21 will be described. A portal frame 23 is erected on a table 22 of the printing apparatus 21. The frame 23 has a pair of columns 24 and 24 on the table 22 at locations spaced apart from each other in the Y direction. A first cross rail 25 is supported between the columns 24 and 24 on the frame 23. Between the frame 23 and the first cross rail 25, a first moving mechanism (not shown) for moving the first cross rail 25 in the Y direction with respect to the frame 23 is provided.

  A second cross rail 26 is supported near the side of the first cross rail 25. Between the 1st and 2nd cross rails 25 and 26, the 2nd moving mechanism (illustration omitted) which moves the 2nd cross rail 26 to a X direction with respect to the 1st cross rail 25 is provided.

  Further, an ink head 27 in an ink jet printer is supported on the second cross rail 26. A third moving mechanism (not shown) for moving the ink head 27 in the Z direction with respect to the second cross rail 26 is provided between the second cross rail 26 and the ink head 27.

  As shown schematically in FIG. 4, the ink head 27 has a substantially rectangular parallelepiped shape that is slightly longer in the Y direction than in the X direction. The ink head 27 includes an ink chamber (not shown) for storing ultraviolet curable ink, and a nozzle group that includes an opening of the ink chamber and includes a plurality of nozzles exposed on the bottom surface of the ink head 27. 28 are provided. The nozzle group 28 is disposed in the ink head 27 at a position biased to one end (left side in FIG. 4) in the Y direction. In the ink head 27, the piezoelectric element constituting the wall of the ink chamber is vibrated, and ink droplets are ejected downward from each nozzle of the nozzle group 28. The ink head 27 has various methods such as a pressure pulse method and a charge control method. The operation of the ink head 27 (piezoelectric element) described above is controlled by a printer controller (not shown). As described above, the area where ink can be ejected from the nozzle group 28 at a time is smaller than the printing surface of the substrate 11 that is the printing object.

  Further, in the ink head 27, an ultraviolet irradiation lamp 29 for irradiating ultraviolet rays UV downward is incorporated in an end portion (right end portion in FIG. 4) opposite to the nozzle group 28 in the Y direction.

  In addition, each 1st-3rd moving mechanism mentioned above can be comprised by a motor, a ball screw, etc., for example. By operating each of these moving mechanisms, the ink head 27 can be linearly moved in the X direction, the Y direction, and the Z direction.

  As shown in at least one of FIGS. 1 and 2, a flat base 31 is fixed on the table 22. On the base 31, a pair of first bearings 32 and 32 are provided at locations separated from each other in the Y direction. A flat plate-shaped first movable plate 33 is disposed between the first bearings 32 and 32. First shafts 34 and 34 are respectively fixed to both side surfaces of the first movable plate 33 in the Y direction. In these first shafts 34 and 34, the first movable plate 33 is connected to the first bearings 32 and 32. 32 is rotatably supported. One of the first shafts 34 and 34 is drivingly connected to an output shaft 36 of a first motor 35 fixed on the base 31. The first motor 35 can rotate the first movable plate 33 around the first shafts 34 and 34 to adjust the inclination thereof.

  On the first movable plate 33, a pair of second bearings 37, 37 are provided at locations separated from each other in the X direction. A second movable plate 38 is disposed between the second bearings 37 and 37. A second shaft 39 (only one is shown in FIG. 2) is fixed to both side surfaces in the X direction of the second movable plate 38, and the second movable plate 38 is connected to both the second shafts 39. Two bearings 37 and 37 are rotatably supported. One of the second shafts 39 is drivingly connected to an output shaft 42 of a second motor 41 fixed on the first movable plate 33. By the second motor 41, the second movable plate 38 can be rotated around both the second shafts 39, and the inclination thereof can be adjusted.

The second movable plate 38 is provided with a gripping device (not shown) for gripping the printing stand 17 on which the substrate 11 is mounted.
The printing device 21 further includes a control device (not shown) configured mainly with a microcomputer. A control program for controlling each operation (position, speed, etc.) of the first to third moving mechanisms, the first motor 35, and the second motor 41 is stored in the memory of the control device. And a control apparatus controls the action | operation of each moving mechanism and the motors 35 and 41 according to this control program.

  Each moving mechanism and the motors 35 and 41 are operated in accordance with this control, whereby the ink head 27 is moved in at least one of the X, Y, and Z directions when ink is ejected. Further, the base material 11 is rotated around at least one of the first shaft 34 and the second shaft 39. By these movement and rotation, the distance D from the nozzle group 28 to the printing surface is maintained at a predetermined value. The predetermined value here is a value with which the printed pattern (pattern) is not blurred or blurred with respect to the distance D, and is a value within a range of 2 to 5 mm.

  For example, when printing is performed on both side surfaces 13 and 13 in the X direction of the base material 11, the first movable plate 33 is rotated around the first shaft 34 by the first motor 35, and the base material 11 is illustrated. 6 (A), the both sides 13 and 13 are positioned up and down. The second cross rail 26 is moved in the X direction by the second moving mechanism, and the nozzle group 28 is positioned above the upper side surface 13. The position of the ink head 27 in the Z direction is adjusted by the third mechanism so that the distance D from the nozzle group 28 to the upper side surface 13 becomes the predetermined value. In this state, the ink 30 is ejected downward from the nozzle group 28 while moving the first cross rail 25 in the Y direction by the first mechanism.

  When printing on the upper surface 12 of the base material 11, since the upper surface 12 is gently curved upward, the second motor 41 slowly moves the second movable plate 38 around the second shaft 39. Rotate. Further, as shown in FIG. 5, the position of the ink head 27 in the Z direction is adjusted by the third mechanism so that the distance D from the nozzle group 28 to the upper surface 12 of the substrate 11 becomes the predetermined value. In this state, the ink 30 is ejected downward from the nozzle group 28 while moving the first cross rail 25 in the Y direction by the first mechanism.

  Further, when printing is performed on both side surfaces 15 and 15 in the Y direction of the base material 11, the second movable plate 38 is rotated around the second shaft 39 by the second motor 41, and the base material 11 is moved. As shown in FIG. 6 (B), the upright state is set, and both side surfaces 15 and 15 are positioned vertically. The position of the ink head 27 in the Z direction is adjusted by the third mechanism so that the distance D from the nozzle group 28 to the upper side surface 15 becomes the predetermined value. In this state, the ink 30 is ejected downward from the nozzle group 28 while the first cross rail 25 is slightly moved in the Y direction by the first moving mechanism.

  As described above, the ink 30 ejected from the nozzle group 28 is attached to the printing surface (side surfaces 13, 13, 15, 15, and the upper surface 12) of the substrate 11. At this time, the ink 30 from the nozzle group 28 located at a predetermined distance D on the upper surface 12 of the substrate 11, on both side surfaces 13 and 13 in the X direction, and on both side surfaces 15 and 15 in the Y direction. Is injected. For this reason, the ink 30 is attached to any portion of the printing surface without causing the printed pattern to blur or blur. Then, the ink 30 attached in this way is immediately cured by the ultraviolet ray UV irradiated from the ultraviolet irradiation lamp 29.

According to the embodiment described in detail above, the following effects can be obtained.
(1) When the ink 30 is ejected, both the ink head 27 and the printing material (base material 11) are displaced while the distance D from the nozzle group 28 to the printing surface is kept constant (predetermined value). Therefore, as compared with the case where the ink head is fixed and only the printed material is displaced as in Patent Document 1, the printed material (base material 11) is slowly displaced, so that the nozzle group 28 and the printed material (base material 11) The ink 30 can be adhered to the printing surface with high accuracy.

  (2) The ink head 27 is linearly moved in the horizontal direction (X direction, Y direction) and the vertical direction (Z direction). For this reason, the distance D from the nozzle group 28 to the printing surface can be reliably maintained at a predetermined value while performing simple movement. Further, the movement of the ink head 27 as described above (linear movement in the X direction, the Y direction, and the Z direction) can be realized with a relatively simple structure.

  (3) About the to-be-printed material (base material 11), this is rotated around at least one of the first shaft 34 and the second shaft 39. Therefore, the distance D from the nozzle group 28 to the printing surface can be reliably maintained at a predetermined value while the movement is relatively simple. Further, the movement of the substrate (base material 11) as described above (rotational movement around the first shaft 34 or the second shaft 39) can be realized with a relatively simple structure.

  (4) The ultraviolet ray curable ink 30 is used, and when the ink 30 is jetted onto the printing surface (substantially simultaneously), the ultraviolet ray UV is irradiated toward the printing surface. Therefore, the ink 30 ejected from the nozzle group 28 and attached to the printing surface can be cured in a short time.

Note that the present invention can be embodied in another embodiment described below.
(A) The present invention can also be applied to the case where decoration is performed by printing on a printing material provided with an opening on the printing surface. That is, the printed surface includes the side surface of the printed material as described in the above embodiment, but also includes the peripheral portion of the opening in the switch base or the like as the printed material.

  As shown in at least one of FIGS. 7 and 8, generally, the switch base substrate 51 is provided with an opening 54 for incorporating the switch 53 at a location different from the side surface 52, for example, the central portion of the upper surface 56. Is provided. The boundary portion between the inner wall surface 55 and the upper surface 56 of the opening 54, that is, the peripheral portion 57 can also be a printing target (printed surface).

  When the above printing method is applied to the printed material (base material 51) having the opening 54 on the upper surface 56 in this way, the print pattern (pattern) is related to the distance D from the nozzle group 28 to the upper surface 56. There is a range that does not blur or blur. When the peripheral edge 57 of the opening 54 is formed by the curved surface 58, the distance from the nozzle group 28 to the farthest end 59 of the curved surface 58 increases as the radius of curvature R of the curved surface 58 increases, and the above range is satisfied. It becomes easy to cross.

  In response to this, it is conceivable that the printed material (base material 51) is inclined so that the distance is within the above range. However, when the curved surface 58 is that of the peripheral edge portion 57 of the opening 54 that opens on the upper surface 56 as described above, the upper surface 56 exists at least around the opening 54. Therefore, if the substrate (base material 51) is excessively tilted as indicated by a two-dot chain line in FIG. 7, the substrate (base material 51) is positioned on the path of the ink head 27 moving in the horizontal direction, causing interference. There is a risk.

  Further, when the upper surface 56 and the peripheral portion 57 are viewed from a direction orthogonal to the upper surface 56 that is a part of the printing surface (upward in FIGS. 7 and 8), as the curvature radius R of the curved surface 58 increases ( As shown in FIG. 8, the area to be visually checked is increased for the peripheral portion 57, and the printing state on the curved surface 58 is easily noticeable.

  Therefore, it is desirable to set the curvature radius R of the curved surface 58 to 2 mm or less. In this way, there is an advantage that the ink 30 can be attached to the curved surface 58 without deteriorating the appearance without the upper surface 56 being inclined with respect to the horizontal plane.

  (B) The ink head 27 may be moved only in the horizontal direction (X direction, Y direction), and the displacement in the vertical direction (Z direction) may be performed on the substrate (substrate 11) side. Further, the ink head 27 may be moved only in the Y direction, and the displacement in the X direction and the vertical direction (Z direction) may be performed on the substrate (substrate 11) side.

(C) The distance D from the nozzle group 28 to the printing surface does not necessarily have to be kept strictly constant (predetermined value), and may be kept substantially constant.
(D) You may make it perform irradiation of the ultraviolet-ray with respect to the to-be-printed surface at the timing different from the ejection timing of the ink 30 to the to-be-printed surface.

  (E) Second movable of the base 11 and the printing stand 17 in a posture different from the above embodiment, for example, in a posture in which the side surfaces 15 and 15 are parallel to the Y direction and the side surfaces 13 and 13 are parallel to the X direction. You may attach to the board 38. FIG.

(F) The printed material is not limited to a synthetic resin and may be formed of other materials such as metal.
(G) The present invention may be applied to printing of vehicle parts other than vehicle interior parts and products used for applications other than vehicles.

In addition, the technical ideas that can be grasped from the respective embodiments will be described together with their effects.
(A) In the method of printing a three-dimensional surface according to claim 1, when the ink head is moved in the horizontal direction, the ink head is linearly reciprocated in the width direction of the printing surface, Move linearly in the length direction. Here, the Y direction in the embodiment corresponds to the width direction, and the X direction in the embodiment corresponds to the length direction.

  (B) In the three-dimensional surface printing method described in (A) above, the ink head is further linearly moved in the vertical direction when the nozzle group is displaced. Here, the Z direction in the embodiment corresponds to the vertical direction.

  (C) In the method for printing a three-dimensional surface according to claim 1, (A) or (B), an axis extending in a width direction of the printing surface when the printing object is displaced, and an axis of the printing surface The printed material is rotated around the axis with at least one of the axes extending in the length direction as a center of rotation. Here, the line extending along both the first shafts 34 in the above embodiment corresponds to the axis extending in the width direction, and the line extending along both the second shafts 39 in the same embodiment is the above. Corresponds to the axis extending in the length direction.

  By moving the ink head as in the invention described in the above (A) or (B), or by displacing (rotating) the printed material as in the invention described in (C), the nozzles can be relatively easily obtained. Printing can be performed by displacing both the ink head and the printing material while keeping the distance from the group to the printing surface substantially constant.

The fragmentary perspective view which shows the printing apparatus used for implementation of the printing method of a three-dimensional surface in one Embodiment which actualized this invention. The fragmentary perspective view which expands and shows the A section in FIG. The perspective view which shows the state before mounting | wearing the base material of the console lid for vehicles as a to-be-printed object with respect to a printing stand. FIG. 3 is a schematic perspective view illustrating a state in which the ink head is viewed obliquely from below. The side view which shows the state which makes ink adhere to the upper surface of to-be-printed material. (A) is a partial side view showing a state in which ink is attached to the side surface in the X direction of the printing material, and (B) is a partial side view showing a state in which ink is attached to the side surface in the Y direction of the printing material. Sectional drawing which shows the state which makes an ink adhere to the curved surface above an opening part in another embodiment using the base material of a switch base as to-be-printed material. FIG. 8 is an enlarged partial cross-sectional view of the upper curved surface of the opening and the vicinity thereof in FIG. 7.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Base material (printed material), 12, 56 ... Upper surface (printed surface), 13, 15 ... Side surface (printed surface), 27 ... Ink head, 28 ... Nozzle group, 30 ... Ink, 54 ... Opening, 57 ... peripheral edge, 58 ... curved surface, D ... distance, R ... radius of curvature, UV ... ultraviolet light.

Claims (3)

A printing object having a non-planar three-dimensional surface as a printing surface is a printing target, the printing material is disposed below an ink head in an ink jet printer, and ink ejected downward from a nozzle group of the ink head A method for printing a three-dimensional surface to be attached to the printing surface,
When ejecting the ink, both the ink head and the substrate to be printed are displaced, including those caused by the horizontal movement of the ink head, while keeping the distance from the nozzle group to the printing surface substantially constant. A method of printing a three-dimensional surface, characterized in that The three-dimensional surface printing method according to claim 1, wherein the ink is an ultraviolet curable ink, and when the ink is jetted onto the printing surface, the ink is irradiated with ultraviolet rays toward the printing surface. The opening of the said to-be-printed object is provided in the said to-be-printed surface, The peripheral part of the opening is formed in the curved surface whose curvature radius is 2 mm or less. Three-dimensional surface printing method.

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