JP5656312B2 - Three-dimensional printer and control method thereof - Google Patents

Description

  The present invention relates to a three-dimensional printer that performs printing on the surface of a three-dimensional object while moving the print object and the printer head while maintaining the relative positional relationship between the print object and the printer head.

  Conventionally, there are various types of printer devices that print characters, graphics, and the like on a printing object such as paper. For example, it is well known to perform printing while moving a print target in a direction perpendicular to the scanning direction while scanning a printer head (see, for example, Patent Documents 1 and 2). Such a conventional printer device performs predetermined printing on a planar sheet material such as planar paper or a resin plate or a flat surface of a solid object, and all performs two-dimensional surface printing. Met. However, in recent years, there is a demand for a three-dimensional printer that performs printing on a three-dimensional surface (for example, a cylindrical surface, a spherical surface, etc.).

  Such a three-dimensional printer that prints on the surface of a three-dimensional shape includes a printer orthogonal to the Y-axis and Y-axis for moving the printer head in a horizontal plane in order to land ink on the print target area from the printer head. X axis for moving the print object in the nozzle array direction of the head, Z axis for moving the print object up and down to keep the distance between the surface of the print object and the printer head constant, and the print object A five-axis structure having an A-axis for rotation and a B-axis for rotating the A-axis in the XZ plane is known (see, for example, Patent Document 3).

JP 2003-191455 A JP 2004-148666 A JP 2008-114493 A

  Using a three-dimensional printer with a five-axis structure as described above, printing that maintains symmetry with respect to the rotation axis, such as a cylinder, cone, or sphere, or that does not change its cross-sectional shape on the central axis, such as an elliptic cylinder It is possible to print on the object. However, the actual shape of the print object is rarely expressed by a simple mathematical expression like any one of the above, and the printer head and print object are moved relative to such a print object. The calculation for obtaining the path to be performed becomes complicated, and there is a problem that printing cannot be performed efficiently.

  The present invention has been made in view of the above-described problems, and provides a three-dimensional printer that can perform printing efficiently without requiring complicated calculations regardless of the shape of a printing object. Objective.

  In order to achieve the above object, a three-dimensional printer according to the present invention has a printer head having a nozzle surface on which a large number of nozzles for ejecting ink are formed, and print target points on the surface of a three-dimensional print target. A three-dimensional printer that discharges ink from the nozzles of the printer head to perform predetermined printing on the surface of the printing object, and holds an object holding apparatus (for example, holding shaft 75, holding in the embodiment) A chuck 76), a three-dimensional movement support device (for example, the first support member 60, the second support member 65, and the third support member 70 in the embodiment) that supports the object holding device so as to be movable in the three-dimensional space. , A head moving support device (for example, supporting the printer head movably so that the nozzle surface passes through a position facing the surface of the printing object held by the object holding device) For example, the carriage 5) in the embodiment and the nozzle surface of the printer head maintain a predetermined interval with respect to the print target point, and the nozzle surface is parallel to the tangent plane of the print target point. Relative movement control devices (for example, the first control device 7 and the second control device in the embodiment) that perform control to move the printer head relative to the print object held by the object holding device by the movement support device and the head movement support device. And a print control device for controlling the ejection of ink from the printer head in accordance with the relative movement control by the relative movement control device.

  In addition, the relative movement control device obtains a normal vector orthogonal to the tangent plane of the print target point from the surface shape of the print target held by the target holding device, and the nozzle surface is relative to the normal vector. It is preferable to perform control to move the printer head relative to the printing object so as to be orthogonal.

  A nozzle array in which nozzles are arranged in a predetermined direction is formed on the nozzle surface, and the object holding device holds the print object rotatably about a rotation axis provided in the three-dimensional space. The relative movement control device has the same length as the nozzle array provided in parallel to the tangent plane of the printing target point and extending in the direction of the rotation axis from the surface shape of the printing target held by the target holding device. It is preferable to perform a control to move the printer head relative to the printing object so that the nozzle line is opposed to the line segment.

  The surface shape of the print object is preferably obtained from CAD data, polygon data, or contour shape data photographed by a three-dimensional photographing machine.

  As described above, in the three-dimensional printer according to the present invention, the relative movement control device maintains the predetermined distance between the nozzle surface of the printer head and the print target point, and the nozzle surface is set against the tangent plane of the print target point. By controlling the printer head to move relative to the print object held by the object holding device by the three-dimensional movement support device and the head movement support device so as to be parallel, the three-dimensional shape print object It is possible to easily calculate the coordinate data (print path) necessary for printing on the printer, and to perform printing efficiently.

  In addition, the relative movement control device obtains a normal vector orthogonal to the tangent plane of the print target point from the surface shape of the print target held by the target holding device, so that the nozzle surface is always the print target. It is possible to easily calculate coordinate data for moving the printer head relative to each other so as to be parallel to the surface.

  Then, the relative movement control device has the same length as the nozzle row provided from the surface shape of the print object held by the object holding device in parallel to the tangent plane of the print target point and extending in the direction of the rotation axis. By obtaining the line segment, coordinate data for moving the printer head relative to each other while optimizing the direction of the nozzle array can be easily calculated.

  In addition, if the surface shape of the printing object is obtained from CAD data, polygon data, or contour shape data photographed by a three-dimensional photographing machine, the above-described data is compared with a case where these data are not used. Such coordinate data can be calculated more easily, and printing can be efficiently performed even for a complicated three-dimensional shape.

  By the same means as described above, for a printer equipped with ultraviolet curable ink and an ultraviolet irradiation device, by replacing the printer head with an ultraviolet irradiation device, not only a printing pass but also a three-dimensional printed object. It is possible to easily calculate the path (curing path) of the UV irradiation device that irradiates the surface of the UV light, and further calculate the feed path that is the path to move from one printing pass to the next. In addition, it is possible to generate a print area on the surface of the print object.

It is a front view of the three-dimensional printer which concerns on one Embodiment of this invention. It is a side view of the three-dimensional printer. It is the schematic explaining the working principle of the three-dimensional printer which concerns on this invention. It is the schematic which shows the relationship between the printer head in the said three-dimensional printer, and a printing target object. (A) is a diagram showing a state in which the lower surface of the printer head is opposed to a print target point, and (b) is a diagram illustrating a state in which the printer head is moved and the print object is rotated so that the lower surface of the printer head is opposed to another print target point. (C) is a diagram showing a state in which the lower surface of the printer head and the ridge line passing through the print target point are not parallel to each other, and (d) is a diagram in which the print object is rotated so that the lower surface of the printer head and the ridge line are parallel to each other. It is a figure which shows the state made to become. It is a figure which shows the method of producing | generating coordinate data, such as a printing pass, with respect to a three-dimensional object. (A) is the figure which calculates | requires the intersection of a reference plane and a three-dimensional object for every predetermined angle, (b) is the figure which connects the intersection calculated | required on the left and calculates | requires the outer periphery curve of the three-dimensional object in a reference plane, (c) is a reference plane FIG. 4D is a diagram for obtaining intersection points between a plane orthogonal to the plane and a three-dimensional object for each predetermined angle, and FIG. 4D is a diagram for obtaining an outer peripheral curve of the three-dimensional object on a plane orthogonal to the reference plane by connecting the intersections obtained on the left. It is a figure which shows the method of producing | generating coordinate data, such as a printing pass, with respect to a three-dimensional object. (A) is a diagram for obtaining an outer peripheral curve of a three-dimensional object in a plane perpendicular to the reference plane at every predetermined angle, and (b) is a diagram connecting the points separated by a predetermined distance from the outer peripheral curve obtained in FIG. 5 (b). The figure which calculates | requires a curve parallel to an outer periphery curve, (c) is a figure which calculates | requires a curve parallel to the said outer periphery curve for every predetermined distance in the vertex direction like the above, (d) is a normal vector and print path from the figure of (c). FIG. It is a figure which shows the state which produces | generates a feed path with respect to a three-dimensional object. It is a figure which shows the expanded view and printing area | region of a three-dimensional object. It is a figure explaining the outline | summary of the three-dimensional printer of 6 axis | shaft structure provided with the C axis | shaft. (A) is a perspective view showing a positional relationship between a printer head and a truncated pyramid-shaped printing object, and (b) is a diagram showing the positions of the six axes.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. First, a configuration of a three-dimensional printer 1 shown as an example of an application target of the present invention will be briefly described with reference to FIGS. 1 and 2. In the following, as shown by the arrows in FIGS. 1 and 2, when the three-dimensional printer 1 is viewed from the front (the paper surface in FIG. 1), the left and right directions and the vertical direction are simply the left and right directions and the vertical direction, respectively. The depth direction (right direction as viewed from the plane of FIG. 2) as viewed from the rear side will be described as the rear direction and the opposite side as the front direction.

  The three-dimensional printer 1 is a printer device that can perform printing on three-dimensional objects having various shapes such as a cylinder, a cone, and a sphere. The three-dimensional printer 1 includes a left support leg 3a, a right support leg 3b, and a support girder 3c that connects the upper ends of the left support leg 3a and the right support leg 3b on the base 2 and extends left and right. The frame 3 is fixed. A first control device 7 having an operation panel 7a is provided adjacent to the right support leg 3b, and a second control device 8 having a maintenance station 9 is provided adjacent to the left support leg 3a. The first control device 7 and the second control device 8 are a movement control device that controls the parallel movement and rotational movement of each member, a print control device that performs ink discharge control of ink discharged from a printer head 11 described later, and A power supply control device for controlling the power supply and the like is provided.

  A pair of left and right guide rails 4a and 4b are provided on the upper surface of the support beam 3c so as to extend in the left-right direction, and a carriage 5 is provided on the left and right (in the direction of the arrow D (y)). As shown in FIG. 2, the carriage 5 is a crank-shaped member that extends forward from the portion supported by the left and right guide rails 4 a and 4 b, bends downward, and further extends forward. A printer head 11 is attached to the front end portion 5 a of the carriage 5. A large number of nozzles (not shown) are formed on the lower surface of the printer head 11 in rows extending in a direction orthogonal to the moving direction of the printer head 11, and ink of the same or different color is ejected from each nozzle. . The front end portion 5a is opened vertically at a portion facing the lower surface of the printer head 11, and desired printing is performed by ejecting ink from the nozzle toward the surface of the printing object 12 positioned below the front end portion 5a. . A head driving device 14 that moves the printer head 11 in the vertical direction is provided above the printer head 11. The carriage 5 on which the printer head 11 is mounted is movable left and right on the left and right guide rails 4a and 4b. The maintenance station 9 is moved upward in a state in which the carriage 5 is located at the left end portion. 9, the nozzles on the lower surface of the printer head 11 are cleaned, dry prevention measures, and the like are performed.

  A pair of front and rear guide rails 2a and 2b extending in the front-rear direction is provided at a position between the left support leg 3a and the right support leg 3b in the upper part of the base 2, and as shown in FIG. 2, the front and rear guide rails 2a and 2b are provided. A first support member 60 is provided on the upper portion of the first support member movably in the front-rear direction (arrow D (x) direction). On the upper part of the first support member 60, a vertical support member 61 is provided in a vertically standing state, and a pair of upper and lower guide rails 62 a and 62 b are provided in front of the vertical support member 61 so as to extend in the vertical direction. . Further, a second support member 65 is provided in a state of being supported by the upper and lower guide rails 62a and 62b so as to be movable in the vertical direction (arrow D (z) direction). The front surface 65a of the second support member 65 passes through a predetermined point p1 determined with respect to the second support member 65 (a point set at a position where a print object 12 to be described later can be positioned) and extends in the left-right direction. A third support member 70 having a cylindrical surface rear surface 70a joined to the cylindrical surface front surface 65a is slidable along the front surface 65a. Is provided. That is, the rear surface 70 a of the third support member 70 is slidable with the front surface 65 a of the second support member 65, whereby the third support member 70 has the first rotation axis Y 0 with respect to the second support member 65. It is supported by being freely rotatable (rotated in the direction indicated by arrow B) as a center.

  In order to rotate the third support member 70 thus supported with respect to the second support member 65 about the first rotation axis Y0, a drive motor 66 is provided on the front surface of the left side portion of the third support member 70 in FIG. The drive pinion 67 attached to the drive shaft (not shown) of the drive motor 66 is meshed with the internal gear 71. Therefore, the drive pinion 67 is driven to rotate by the drive motor 66, and the internal gear 71 rotates accordingly, and the third support member 70 is rotated in the direction indicated by the arrow B around the first rotation axis Y0 (hereinafter referred to as the B-axis direction). Can be rotated.

  On the front surface side of the third support member 70, a holding shaft 75 extends in the front-rear direction, is rotatably provided around the second rotation axis X0 passing through the predetermined point p1, protrudes forward, and has a print target at the front end. A holding chuck 76 for holding 12 is attached. The holding shaft 75 is rotationally driven by a drive motor (not shown) disposed inside the third support member 70, and the holding chuck 76 is configured to hold the printing object 12. ing. Therefore, if the holding shaft 75 is rotationally driven in a state where the printing object 12 is held by the holding chuck 76, the printing object 12 is moved in the direction of the arrow A about the second rotation axis X0 (hereinafter referred to as the A axis). Can be rotated. Further, since the third support member 70 is rotatable in the B-axis direction around the first rotation axis Y0, the second rotation axis when the third support member 70 is located at a predetermined rotation position (position shown in FIG. 2). X0 extends in the front-rear direction, but the second rotation axis X0 is swung up and down in accordance with the rotation of the third support member 70 in the B-axis direction.

  In the three-dimensional printer 1 configured as described above, an operation principle for performing printing on the print object 12 and an outline of the relative movement control between the print object 12 and the printer head 11 will be described with reference to FIG. To do. In FIG. 3, the second rotation axis X0 that is the rotation center of the holding shaft 75 corresponds to the X axis, and the first rotation axis Y0 that is the rotation center of the third support member 70 corresponds to the Y axis. Note that the print object 12 shown in FIG. 3 is a frustoconical member, and will be described below using the print object 12. Actually, the shape of the print object is not limited to the truncated cone shape, and printing is possible for three-dimensional objects having various shapes such as a cylindrical shape, an elliptical cylindrical shape, and a conical shape.

  First, as described above, the three-dimensional printer 1 includes first to third support members 60, 65, 70 and a holding chuck 76 that support the print object 12, and these first to third support members 60, The print object 12 is supported by the rollers 65 and 70 and the holding chuck 76 so as to be rotatable in the A-axis direction around the X-axis. In this state, the print object 12 passes through a predetermined point p1 on the X-axis and extends right and left perpendicular to the X-axis. The print object 12 is supported so as to be rotatable in the B axis direction around the Y axis, and the print object 12 is moved back and forth along the X axis direction (in the direction indicated by the arrow D (x)). It is configured to be movable and supported so as to be movable up and down (in the direction indicated by the arrow D (z)) along the Z axis extending perpendicularly to the X axis and the Y axis.

  Above the print target 12 supported in this manner, the printer head 11 is disposed in a state in which it can move in the direction indicated by the arrow D (y) (hereinafter referred to as the Y-axis direction). The drive device 14 can move the printer head 11 in the direction indicated by the arrow D (z) (hereinafter referred to as the Z-axis direction). The printer head 11 discharges ink supplied from an ink supply device (not shown) for each nozzle based on the control of a print control device (not shown), and holds the surface of the printed object 12. Predetermined printing is applied to the printer.

  By the way, when printing is performed, the nozzle is moved to a position close to the print target position on the surface of the print object 12 having a predetermined print interval (the ink discharged from the nozzle is attached to the surface of the print object 12 for printing. It is necessary to be located at a position having an optimum interval to perform. Furthermore, the direction of ink ejection from the nozzles must be orthogonal to the print target position on the surface. Specifically, as shown in FIG. 3, the printer head 11 is placed on a tangential plane with the midpoint of the printing line 13 a formed from the point whose lower surface (nozzle surface on which the nozzles are formed) is the printing target. The nozzle surface needs to be moved so as to be parallel to each other and to be positioned at a predetermined printing interval from the midpoint.

  Therefore, in order to perform the above movement, first, the printing object 12 is moved in the direction indicated by the arrow D (x) (hereinafter referred to as the X-axis direction). Then, the print object 12 is rotated in the A-axis direction so that the print line 13a to be printed is positioned directly above, and the print object 12 is further rotated in the B-axis direction to align the nozzle array of the printer head 11 The ridgeline L0 passing through the print line 13a is positioned so as to be parallel to each other. Then, the nozzle surface of the printer head 11 is moved in the direction indicated by the arrow D (z) so as to be located at a position away from the midpoint of the printing line 13a by a predetermined printing interval. Note that the above movement, rotation, and the like may be performed in any order as long as the printing object 12 and the printer head 11 do not interfere with each other.

  As described above, the nozzle surface of the printer head 11 is parallel to the tangent plane of the midpoint of the print line 13a, and the nozzle surface of the printer head 11 is separated from the midpoint of the print line 13a by a predetermined printing interval. From the ink to the printing line 13a. For example, when printing is performed on the print line 13b and the print line 13c that are formed at positions along the circumferential direction on the surface of the print object 12 from the print line 13a and extend in the direction toward the X-axis (rotation axis) direction, Similar to the printing line 13a, the nozzle surface of the printer head 11 is separated from the middle point by a predetermined printing interval, and the nozzle surface of the printer head 11 is parallel to the tangent plane of the middle point of each of the printing line 13b and the printing line 13c. As described above, printing is performed while the printer head 11 and the printing object 12 are translated and rotated. In this way, while the nozzle surface of the printer head 11 is separated from the print line 13b and the print line 13c by a predetermined printing distance, the nozzle surface of the printer head 11 is parallel to the tangent plane of the middle point of each of the print line 13b and the print line 13c. In such a state, the ink is ejected onto the printing lines 13b and 13c. In this way, desired printing can be performed by sequentially ejecting ink at regular intervals on the surface of the print object 12 at the print lines 13a, 13b, 13c,.

  As described above, the three-dimensional printer 1 in the present embodiment is provided in the direction perpendicular to the X axis and the X axis for moving the printing object 12 in the nozzle row direction of the printer head 11 and for moving the printer head 11. The Y axis, the Z axis for moving the printer head 11 and the printing object 12 in the vertical direction, the A axis for rotating the printing object 12 around the X axis, and the printing object 12 around the Y axis It has a 5-axis moving mechanism with a B-axis to rotate.

  For example, when printing on the elliptical prism-shaped print target 22, a print target point B1 which is a part of the surface of the print target 22 shown in FIGS. 4A and 4B and is separated from the print reference point B0. In order to land the ink with high accuracy when printing on the printing line located at the position, the vertical Y0 axis of the printer head 11 and the normal direction of the printing line always coincide with the surface of the printing object 22. As shown in FIG. 4B, printing is performed by moving the print target 12 in the A-axis direction by the rotation angle b1 and moving the printer head 11 to the position y1.

  Further, when printing on a truncated cone-shaped printing object 12 as shown in FIG. 4C, the surface of the printing object 12 and the nozzle surface of the printer head 11 are parallel, or the printing object When the object 12 is an object having a curvature, the A-axis is inclined in the B-axis direction by an inclination angle a1 as shown in FIG. 4D so that the tangent plane of the printing target point is parallel to the nozzle surface. Let Further, in order to keep the distance g between the nozzle surface of the printer head 11 and the print area of the print object 12 constant, the Z coordinate is set to z1 and the X coordinate is set to x1, and the reference point of the print area and the reference point of the nozzle Match.

  In order to perform printing by continuously ejecting ink onto the printing lines 13a, the printing lines 13b, the printing lines 13c,... On the surface of the printing object 12 using the above principle, each printing line 13a, printing is performed. It is necessary to obtain values of coordinate data indicating positions on the X-axis, Y-axis, Z-axis, A-axis, and B-axis corresponding to the line 13b, the print line 13c,. Hereinafter, a procedure for generating these coordinate data and a method such as printing based on the generated coordinate data will be described. In the three-dimensional printer 1, the movement control device and the print control device (the first control device 7 and the second control device 8) described above perform relative movement of the printer head 11 and the printing object 12, and ink discharge. Is called. The three-dimensional printer 1 is preliminarily provided with CAD data, polygon data, or surface shape data of a printing object obtained by a three-dimensional photographing machine, and the surface shape data is digitized in advance and the X axis, Y It is formed in an XYZ space composed of an axis and a Z axis. In the following, description will be given using an example in which coordinate data such as a print pass described later is obtained and printed on a dome-shaped three-dimensional object 100 as shown in FIG.

  First, as shown in FIG. 5A, a reference surface for starting printing (hereinafter referred to as a reference surface), a rotation axis orthogonal to the reference surface and passing through the center of the three-dimensional object 100, and a reference surface And the three-dimensional object 100 is defined as an intersection 31 (1) and rotated from the intersection 31 (1) by an angle θ1 about the rotation axis to obtain the outer peripheral shape of the three-dimensional object 100 on the reference plane. Specifically, for example, when the reference plane is the YZ plane and the rotation axis is the X axis, as shown in FIG. 5A, first, the intersection 31 (1) that is the intersection of the YZ plane and the three-dimensional object 100 is used. Are rotated by an angle θ1 about the X axis, and the intersections of the YZ plane and the three-dimensional object 100 are sequentially obtained as 31 (2)... 31 (n). Then, the intersection points 31 (1) to (n) are interpolated with an interpolation curve to generate an outer peripheral curve 32 (1) as shown in FIG. 5B. Note that n can theoretically be a natural number of 2 or more, but is preferably a large number to increase accuracy. As the type of interpolation curve used at this time, a spline curve can be used. However, if a curve can be generated from n points, other interpolation methods such as Lagrange interpolation can be used.

  After generating the outer periphery curve 32 as described above, a printing start point is determined. As the print start point, a point on the outer peripheral curve 32 can be used. Here, as shown in FIG. 5C, the intersection of the outer peripheral curve 32 (1) and the Z axis is set as the print start point 33 (1 ). Then, the same point as the printing start point 33 (1) is set as the intersection point 34 (1), and is rotated by an angle θ2 around the axis parallel to the reference plane from the intersection point 34 (1) to be orthogonal to the reference plane. The outer peripheral shape of the three-dimensional object 100 on the surface to be obtained is obtained. Specifically, for example, when a plane orthogonal to the reference plane (YZ plane) is set as an XZ plane and rotated from the intersection point 34 (1) by the angle θ2 around the Y axis, the XZ plane is sequentially formed from the intersection point 34 (1). And the three-dimensional object 100 can be obtained as 34 (2), 34 (3)... 34 (n). Note that θ2 is determined so that the last intersection 34 (n) coincides with the X-axis, and can be π / {2 (n−1)} (rad). The intersections 34 (1) to (n) are interpolated by an interpolation curve as in the intersections 31 (1) to (n), and a curve 35 (1) is generated as shown in FIG. As the type of interpolation curve used at this time, a spline curve or the like can be used as in the intersections 31 (1) to (n), and various other interpolation methods can be used.

  Further, in the outer peripheral curve 32 (1) shown in FIG. 5B, an interval ΔL is defined based on a predetermined printing resolution (see FIG. 6A), and similarly to the curve 35 (1) described above, Curves 35 (2)... 35 (n) are generated for each interval ΔL. These curves 35 (1) to (n) correspond to meridians on the globe as shown in FIG. 6 (a). Here, the intersection of the curve 35 (1) and the outer curve 32 (1) is a reference point 36 (1), the reference point of the curve 35 (2) and the outer curve 32 (1) is 36 (2),. A reference point between the curve 35 (n) and the outer curve 32 (1) is defined as 36 (n). Then, as shown in FIG. 6B, points on the three-dimensional object 100 that are separated from the reference points 36 (1) to (n) on the curves 35 (1) to (n) by the distance d are points 37, respectively. (1) to (n). In addition, the points 37 (1) to (n) are interpolated by a spline function or the like to obtain the curve 32 (2). In the same way, as shown in FIG. 6C, curves 32 (3)... (N) are generated for each distance d. The curves 32 (1) to (n) correspond to latitude lines on the globe. The distance d is determined to be the same as the length of the nozzle row, and the value n of the curve 32 (n) can be printed on the target print area using the nozzle of the length. It has become a value.

  Then, as shown in FIG. 6D, the line segment between the outer peripheral curve 32 (1) and the curve 32 (2) on the curve 35 (1) is defined as a line segment 38 (1) and a curve 35 (2). The line segment between the upper peripheral curve 32 (1) and the curve 32 (2) is the line segment 38 (2)..., And the outer peripheral curve 32 (1) and the curve 32 (2) on the curve 35 (n). Line segment 38 (n), these line segments 38 (1) to (n) first make one round while discharging ink from the printer head 11 to the surface of the three-dimensional object 100. This is the coordinates for the print pass to be performed. That is, the lengths of the line segments 38 (1) to (n) are the same as the lengths of the nozzle rows. After these line segments 38 (1) to (n) are obtained, the printer head 11 is along these lines 38 (1) to (n). Printing is performed by ejecting ink while moving the position of the nozzle row.

  As coordinate data (print path) for printing on the three-dimensional object 100, as shown in FIG. 6D, from the midpoint of each of the line segments 38 (1) to (n) to the midpoint. Vertical normal vectors 39 (1) to (n) are obtained. These normal vectors 39 (1) to (n) are normal vectors on the surface for making the nozzle surface of the printer head 11 and the surface of the three-dimensional object 100 parallel to each other. The plane moves while maintaining a state orthogonal to the normal vectors 39 (1) to (n). Further, the angle formed by the normal vectors 39 (1) to (n) and the XZ plane corresponds to the A coordinate (inclination in the A-axis direction) of the three-dimensional object 100 described above. Furthermore, the position of the starting point of the normal vectors 39 (1) to (n) corresponds to the above-described X coordinate (the position in the X-axis direction), and the distance between the starting point and the reference point of the coordinate system is that of the three-dimensional object 100. It is the radial distance from the center of rotation to the surface.

  As described above, based on the line segments 38 (1) to (n) and the normal vectors 39 (1) to (n), the coordinate data x, y, z, a, and b can be obtained, and printing can be sequentially performed on the surface of the three-dimensional object 100 by moving the printer head 11 and the three-dimensional object 100 in parallel and rotating using these coordinate data. In the above method, as printing progresses to the top (as the curve 32 (1) progresses to the curve 32 (n)), the resolution increases and the image quality improves. Since it can be dealt with by another method such as image processing, the description is omitted in this embodiment.

  As described above, the printer head 11 is kept on the line segments 38 (1) to (n) of the three-dimensional object 100 while maintaining the state in which the nozzle surface is orthogonal to the normal vectors 39 (1) to (n). Can be moved relative to each other to discharge ink and print on the line segments 38 (1) to (n) (first printing pass). In the same manner, the printing on the three-dimensional object 100 is completed through the remaining n-1 printing passes while the printer head 11 is further moved n-1 round relative. At this time, for example, after the printing of the line segments 38 (1) to (n) (first printing pass) using the outer peripheral curve 32 (1) as a reference line is completed, the curve 32 (2) is continuously set as a reference. Printing as a line (second printing pass) cannot be performed, and it is necessary to interpose a feed pass when shifting from the previous printing pass to the next printing pass. That is, after the first printing pass is completed, the printer head 11 makes one round on the three-dimensional object 100 without discharging ink in order to shift the reference line from the outer peripheral curve 32 (1) to the curved line 32 (2). The relative rotation is necessary. Specifically, it is necessary to shift the reference line from the outer peripheral curve 32 (1) to the curve 32 (2) while the printer head 11 is relatively rotated from the curve 35 (1) to (n). Hereinafter, a method for obtaining a route (feeding path) for this transition will be described.

  As the feed path, as shown in FIG. 7, a line segment 40 moved from the line segment 38 (1) on the curve 35 (1) to the curve 32 (2) side (vertex side) by d × 1 / n. (1), line segment 40 (2)..., Curve 35 (n) moved from the line segment 38 (2) on the curve 35 (2) to the curve 32 (2) side by d × 2 / n The line segment 40 (n) moved from the line segment 38 (n) to the curve 32 (2) side by d × n / n (= d) can be used. Further, normal vectors 41 (1) to (n) perpendicular to the respective midpoints are obtained from the midpoints of these line segments 40 (1) to (n). Then, on these line segments 40 (1) to (n), the normal vectors 41 (1) to (n) and the nozzle surface of the printer head 11 are kept orthogonal, and ink is not ejected. The route moved to is a feed path.

  After the first printing pass is finished with the outer periphery curve 32 (1) as the reference line, the reference line is moved from the outer periphery curve 32 (1) to the curve 32 (1) while moving the printer head 11 without ejecting ink as described above. It is possible to shift to the next print pass (print pass with the curve 32 (2) as a reference line) via the feed pass to shift to 2). In the above, a path for shifting the reference line while the printer head 11 is rotated once in a non-printing state is shown as a feed path. However, if the mechanical operation speed is improved, the printer head 11 is moved. For example, a path for shifting the reference line during a half-turn or a quarter-turn can be used as a feed path. In addition, when the actual print area is smaller than the printable area (when the non-print area is large), a path for shifting the reference line on the non-print area can be used as a feed path.

  Further, the method for generating the print pass and the feed pass can be applied to ultraviolet irradiation when ultraviolet curable ink (hereinafter referred to as UV ink) is used. That is, it can be applied to a curing pass in which a UV light source that irradiates UV light to UV ink after UV ink discharge is scanned. A method for generating this curing pass will be described below. Hereinafter, an example in which the UV light source is supported so as to be movable in the Y-axis direction in the same manner as the printer head 11 will be described.

  In the curing pass, it is basically necessary to move the UV light source directly above the surface of the three-dimensional object 100 as in the printing pass. That is, it is necessary to generate a curing pass on the assumption that the UV light source is arranged in parallel to the surface of the three-dimensional object 100. The curing pass is a first pass in which the UV light source is moved immediately above the surface of the three-dimensional object 100 after the discharge of UV ink to the surface of the three-dimensional object 100 is completed and the printer head 11 is retracted, and ultraviolet light is transmitted. It comprises a second pass for performing the UV curing process while irradiating, and a third pass for retracting the UV light source to the original position after the UV curing process.

  An example of rotating the three-dimensional object 100 once in each of the first to third passes will be described. First, as the first pass, after the printing pass is completed once, the same coordinate data as the printing pass is used. Based on the path for rotating the three-dimensional object 100 and moving the UV light source directly above the three-dimensional object 100 during the rotation, that is, the path for changing the Y coordinate of the UV light source. Further, the second pass can be generated by obtaining a path for relatively rotating the UV light source on the three-dimensional object 100 in the same manner as the printing pass. The third pass can be generated while the three-dimensional object 100 is rotated once. Can be generated by a path for returning the printer head 11 to the position immediately above the three-dimensional object 100, that is, a path for changing the Y coordinate of the UV light source as in the first path.

  The relationship between the curing pass and the printing pass is described above, for example, during the third pass after the curing process (withdrawing the UV light source and moving the printer head 11 onto the three-dimensional object 100). The feed pass may be executed. Similarly to the feed pass, when the mechanical operation speed is improved, the curing pass (first to third passes) is quickly executed while the three-dimensional object 100 is half-rotated, for example, without rotating the three-dimensional object 100 once. You can also.

  Next, a method for obtaining a print area that is a target for ejecting ink of the printer head 11 from the three-dimensional object 100 will be described with reference to FIG. First, the outline of the print area is shown in a developed view with the curves 32 (1) to (n) shown in FIG. 6B or the like as reference lines (ink landing points). FIG. 8 shows the developed view. This developed view is based on the print start point 33 (1), that is, has a shape developed with the print start point 33 (1) directly below the center. .

  Then, the printing resolution is set to a constant value, and the value obtained by dividing the length of the outer peripheral curve 32 (1) serving as the printing reference by the printing resolution in the above development view is the number of dots 50 (1) and the curve 32 (2). The value obtained by dividing the length by the printing resolution is obtained as the number of dots 50 (2)..., And the value obtained by dividing the length of the curve 32 (n) by the printing resolution is obtained as the number of dots 50 (n). The number of dots 50 (1) to (n) includes the print line length between the curves 32 (1) and 32 (2), and between the curves 32 (n-1) and 32 (n). This corresponds to the number of dots of ink droplets ejected from the nozzle corresponding to. In this way, the print area is obtained by obtaining the number of dots 50 (1) to (n) in the curves 32 (1) to (n).

  As described above, a desired image is input into the development view, a print area is obtained based on the above-described print path, and ink is ejected onto the print area, thereby generating an image on the surface of the three-dimensional object 100. Can be made. The print area is created on the assumption that the print resolution is constant. However, since the print resolution may change with the change of the print distance, the print resolution is actually The shape of the print area is corrected in consideration of the change in the print area.

  As described above, the three-dimensional printer 1 according to the present embodiment includes the surface shape data of the print target obtained from CAD data, polygon data, and the like, and based on the surface shape data, the line segments 38 (1) to (n) and Coordinate data such as normal vectors 39 (1) to (n) is generated to enable generation of a print pass, a curing pass, and a print area. Therefore, it is possible to perform printing or the like without requiring complicated calculations as in the prior art.

  The surface shape data is not limited to the CAD data and polygon data as long as the surface shape data includes information capable of calculating the coordinates of the surface shape. The surface shape data that is the basis for determining the printing pass, the generation of the curing pass, and the printing area may be stored in advance as described above, or from the outside before the calculation of the coordinate data. You may make it input.

  In the above description, the three-dimensional printer 1 having a five-axis structure has been described as an example. However, the application target of the present invention is not limited to the three-dimensional printer 1 having the above-described configuration. Further, the present invention can also be applied to a three-dimensional printer having a six-axis structure. For example, in addition to the X-axis, Y-axis, Z-axis, A-axis, and B-axis, as shown in FIG. The present invention can also be applied to a three-dimensional printer having a C axis. As shown in FIG. 9A, this type of three-dimensional printer includes a printer head 111 similar to that of the above embodiment, and the upper bottom surface and the lower bottom surface are rectangular, and the area of the upper bottom surface is larger than the area of the lower bottom surface. It is possible to print on a three-dimensional object 112 having a small truncated pyramid shape. Also, it has a C-axis for turning the three-dimensional object 112 around the Z-axis, and printing is performed while turning along the C-axis, so that a three-dimensional printer with a 5-axis structure can generate a continuous path. Therefore, it is possible to efficiently print the region 112a at the end of the three-dimensional object 112 that cannot be printed efficiently.

  The above-described method for generating coordinate data such as a printing pass from the surface shape data of the present invention can be applied not only to a three-dimensional printer but also to a two-dimensional printer, a cutting plotter, and the like.

1 Three-dimensional printer 5 Carriage (head movement support device)
5a Front end (head movement support device)
7 First control device (relative movement control device, print control device)
8 Second control device (relative movement control device, print control device)
11 Printer head 12, 22 Print target 60 First support member (three-dimensional movement support device)
65 Second support member (three-dimensional movement support device)
70 Third support member (three-dimensional movement support device)
75 Holding shaft (object holding device)
76 Holding chuck (object holding device)
100, 112 3D object (printing object)

Claims (6)

A printer head having a nozzle surface on which a nozzle row in which a large number of nozzles for ejecting ink are arranged in a predetermined direction is formed, and the nozzles of the printer head at a printing target point on the surface of a three-dimensional printing target A three-dimensional printer that discharges ink from the surface to perform predetermined printing on the surface of the print object,
An object holding device for holding the print object;
A three-dimensional movement support device for movably supporting the object holding device in a three-dimensional space;
A head movement support device that movably supports the printer head so that the nozzle surface passes through a position facing the surface of the print object held by the object holding device;
The three-dimensional movement support device, wherein the nozzle surface of the printer head maintains a predetermined distance from the print target point, and the nozzle surface is parallel to a tangential plane of the print target point. A relative movement control device that performs control to move the printer head relative to the print object held by the object holding device by the head movement support device;
A print control device that controls the ejection of ink from the printer head in accordance with the relative movement control by the relative movement control device;
The object holding device holds the print object rotatably about a rotation axis provided in the three-dimensional space,
The relative movement control device includes:
From the surface shape of the printing object held by the object holding device, the reference surface for starting printing on the printing object becomes a reference, and the orthogonal surface passing through the rotation axis is orthogonal to the reference surface orthogonal to the rotation axis. Obtaining a line segment having the same length as the nozzle array provided on the outer peripheral curve of the print object and a normal vector orthogonal to the tangent plane of the print object point;
Performing a control to move the printer head relative to the print object so that the nozzle row faces the line segment and the nozzle surface is orthogonal to the normal vector,
The step of obtaining the line segment and the normal vector includes
A first step of obtaining an outer peripheral curve of the print object on the reference surface ;
The operation for obtaining the outer periphery curve of the printing object on the orthogonal surface is executed for each orthogonal surface separated at intervals defined based on a predetermined print resolution on the outer periphery curve obtained in the first step. A second step;
On the plurality of outer periphery curves obtained by the second step, points that are separated from the reference points on these outer periphery curves by a distance of the same length as the nozzle row are defined, and between each of the determined points. A third step of performing an operation for obtaining a curve by interpolation for each of the reference points separated from the outer peripheral curve obtained by the first step for each of the distances;
A fourth step of obtaining the line segment by dividing the outer peripheral curve obtained by the second step by the outer peripheral curve obtained by the first step and the plurality of curves obtained by the third step; When,
And a fifth step of obtaining the normal vector perpendicular to the midpoint from the midpoint of each of the line segments obtained in the fourth step.   The three-dimensional printer according to claim 1, wherein the surface shape of the printing object is obtained from CAD data, polygon data, or contour shape data photographed by a three-dimensional photographing machine. A printer head having a nozzle surface on which a nozzle row in which a large number of nozzles for ejecting ink are arranged in a predetermined direction is formed, and the nozzles of the printer head at a printing target point on the surface of a three-dimensional printing target A three-dimensional printer that discharges ink from the surface to perform predetermined printing on the surface of the print object,
An object holding device for holding the print object;
A three-dimensional movement support device for movably supporting the object holding device in a three-dimensional space;
A head movement support device that movably supports the printer head so that the nozzle surface passes through a position facing the surface of the print object held by the object holding device;
The three-dimensional movement support device, wherein the nozzle surface of the printer head maintains a predetermined distance from the print target point, and the nozzle surface is parallel to a tangential plane of the print target point. A relative movement control device that performs control to move the printer head relative to the print object held by the object holding device by the head movement support device;
A print control device that controls the ejection of ink from the printer head in accordance with the relative movement control by the relative movement control device;
The object holding device is a control method of the three-dimensional printer that rotatably holds the print object around a rotation axis provided in the three-dimensional space,
In the relative movement control device,
From the surface shape of the printing object held by the object holding device, the reference surface for starting printing on the printing object becomes a reference, and the orthogonal surface passing through the rotation axis is orthogonal to the reference surface orthogonal to the rotation axis. Obtaining a line segment having the same length as the nozzle array provided on the outer peripheral curve of the print object and a normal vector orthogonal to the tangent plane of the print object point;
Performing a control of moving the printer head relative to the print object so that the nozzle row faces the line segment and the nozzle surface is orthogonal to the normal vector. Control to
The step of obtaining the line segment and the normal vector includes
A first step of obtaining an outer peripheral curve of the print object on the reference surface ;
The operation for obtaining the outer periphery curve of the printing object on the orthogonal surface is executed for each orthogonal surface separated at intervals defined based on a predetermined print resolution on the outer periphery curve obtained in the first step. A second step;
On the plurality of outer periphery curves obtained by the second step, points that are separated from the reference points on these outer periphery curves by a distance of the same length as the nozzle row are defined, and between each of the determined points. A third step of performing an operation for obtaining a curve by interpolation for each of the reference points separated from the outer peripheral curve obtained by the first step for each of the distances;
A fourth step of obtaining the line segment by dividing the outer peripheral curve obtained by the second step by the outer peripheral curve obtained by the first step and the plurality of curves obtained by the third step; When,
And a fifth step of determining the normal vector perpendicular to the midpoint from the midpoint of each of the line segments obtained in the fourth step. . The first step, with the reference plane, the orthogonal plane with one of, determine the intersection of the surface of the printing object, is rotated from the predetermined intersection point by a predetermined angle around the rotation axis, the reference The intersection of the surface , the other orthogonal surface, and the surface of the printing object is sequentially obtained, and the outer periphery curve of the printing object on the reference surface is obtained by interpolating between the determined intersection and the obtained intersection. The method for controlling a three-dimensional printer according to claim 3, wherein the method is a determining step. In the second step, one of the straight lines existing on the orthogonal plane passing through the reference plane and the axis passing through the rotation axis and orthogonal to the orthogonal plane on the outer circumference curve obtained in the first step. When, defines the intersection of the surface of the printing object, the set intersection, and around the rotated by a predetermined angle the shaft, sequentially determined and another of the straight line, the intersection of the surface of said printing object, An operation for interpolating between the determined intersection point and the obtained intersection point to obtain the outer periphery curve of the print object on the orthogonal plane is based on a predetermined print resolution on the outer periphery curve obtained by the first step. 5. The method of controlling a three-dimensional printer according to claim 3, wherein the control is executed for each of the orthogonal planes separated at intervals defined by   6. The surface shape of the print object is obtained from CAD data, polygon data, or contour shape data photographed by a three-dimensional photographing machine. Control method for three-dimensional printer.