Three-dimensional object printing system and three-dimensional object printing method

Abstract

To provide a three-dimensional object printing system and a three-dimensional object printing method capable of easily improving the accuracy of printing a three-dimensional object and easily increasing productivity.SOLUTION: The three-dimensional object printing system comprises: a printing table T on which a three-dimensional object 10 is placed; a detection reference mark 15 fixed on the printing table T; detection means 101 for detecting a position of the detection reference mark 15 and a detection point on a surface of the three-dimensional object 10; printing data generation means 102 for generating printing data; printing means 103 for executing printing on the three-dimensional object 10 on the basis of the generated printing data; and control means 104. The printing data generation means 102 calculates a correction value of a printing position on the basis of the position of the detection reference mark 15 detected by the detection means 101 and a position of a printing reference point c, reflects the correction value in calculation of a position and a rotation angle of the three-dimensional object 10, and generates the printing data in accordance with the position and the rotation angle of the three-dimensional object 10 reflecting the correction value.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a three-dimensional object printing system and a three-dimensional object printing method. [Background technology]

[0002] 2. Description of the Related Art Conventionally, an inkjet printer capable of printing an image on a curved print surface of a three-dimensional medium (a three-dimensional object) so that the image appears to have a substantially uniform density, and a printing method using the same are known (see, for example, Patent Document 1).

[0003] Also proposed are a three-dimensional object printing system and a three-dimensional object printing method that do not require rotational control of the three-dimensional object and are capable of performing high-definition printing without using a fixing jig (see, for example, Patent Documents 2 and 3). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2006-335019 A [Patent Document 2] JP 2015-134410 A [Patent Document 3] JP 2018-187915 A Summary of the Invention [Problem to be solved by the invention]

[0005] The problem with Patent Document 1 is that rotation control is required for each three-dimensional object, resulting in extremely low productivity.Patent Document 2 uses a detection reference mark as a reference to determine the position where the three-dimensional object is placed and then prints it, but there is a problem with poor print position accuracy due to an error in the positional relationship between the print position and the detection reference mark.

[0006] On the other hand, in Patent Document 3, multiple detection references are printed on the printing table to reduce the error between the printing position and the detection reference mark. The technology in Patent Document 3 can produce stable, accurate printing with good productivity compared to other technologies.

[0007] However, in this technology, although it is necessary to maintain the relationship between the detection standard and the printing position where the three-dimensional object is printed to be constant in order to maintain the printing position accuracy, there is a problem that printing position errors occur depending on the repeatability of the printing position to be printed. In particular, there is a problem with errors that occur after continuing printing for a long period of time or after the printing operation has been stopped for a certain period of time.

[0008] A method of solving this error problem without sacrificing productivity is to print the detection standard at the same time as printing the three-dimensional object. However, in the case of flatbed inkjet printers and other printing means with excellent productivity, there is a drawback in that the detection standard mark cannot be printed clearly because the distance from the inkjet head (scanning print head) when printing the three-dimensional object placed on the print table to the print table on which the detection standard is printed is large.

[0009] However, in conventional three-dimensional object printing systems and three-dimensional object printing methods, the position of a three-dimensional object is specified based on a plurality of detection reference marks printed on a printing table on which the three-dimensional object is placed. Printing the detection reference marks on the printing table restricts the placement of an object on the printing table, and in some cases, this may affect the determination of the position of the object.

[0010] That is, when the detection reference mark is provided by printing, particularly for a three-dimensional object near the detection reference mark, the distance from the detection means to the detection point set on the surface of the three-dimensional object for detecting the orientation of the three-dimensional object, differs from the distance from the detection means to the detection reference mark. For example, when the detection means is an optical system that is affected by the viewing angle or an optical system with a shallow focal depth, there is a problem that the difference in distance is likely to cause errors in detecting the positional relationship between the detection reference mark and the detection point.

[0011] In order to avoid such errors, it is conceivable to print a detection reference mark at a position substantially equal to the distance (height) from the placement surface of the printing table to the detection point on the three-dimensional object.

[0012] However, since it is necessary to adjust the printed height of the detection reference mark for each three-dimensional object to be printed, there is a problem that this is an impediment to increasing productivity.

[0013] Furthermore, even when the difference between the detection point of a three-dimensional object and the printed height of the detection reference mark does not pose a problem due to the focal depth or field of view of the detection means, the printed detection reference mark still has drawbacks, such as deterioration over time due to the print becoming dirty or rubbed, which can cause errors in the detection standard.

[0014] In view of the above circumstances, an object of the present invention is to provide a three-dimensional object printing system and a three-dimensional object printing method that can easily improve the printing accuracy on a three-dimensional object and easily increase productivity. [Means for solving the problem]

[0015] In order to solve the above problem, the three-dimensional object printing system of the present invention includes a printing table on which a three-dimensional object to be printed is placed, a detection reference fixed on the printing table, a detection means for detecting the position of the detection reference and the positions of a plurality of detection points set on the surface of the three-dimensional object, a print data generation means for generating print data corresponding to the three-dimensional object, a printing means for performing printing on the three-dimensional object using the print data generated by the print data generation means, and a control means for controlling the operation of the detection means, the print data generation means, and the printing means, wherein the print data generation means calculates a correction value for the print position based on the position of the detection reference and the print reference point detected by the detection means, reflects the calculated correction value in the calculation of the position and rotation angle of the three-dimensional object, and generates the print data according to the position and rotation angle of the three-dimensional object reflected by the correction value.

[0016] The three-dimensional object printing method of the present invention includes a detection step of detecting the position of a detection point set on the surface of a three-dimensional object placed on a printing table and the position of a detection reference fixed to the printing table; a calculation step of calculating the position and rotation angle of the three-dimensional object based on the detected positions of the detection reference and the detection point; a control step of calculating a correction value for the printing position based on the detected position of the detection reference and the printing reference point, reflecting the calculated correction value in the calculation of the position and rotation angle of the three-dimensional object, and controlling the generation of print data according to the position and rotation angle of the three-dimensional object in which the correction value is reflected; a generation step of generating print data corresponding to the three-dimensional object based on the position and rotation angle of the three-dimensional object in which the correction value is reflected; and a printing step of executing printing on the three-dimensional object using the generated print data. Effect of the Invention

[0017] According to the present invention, it is possible to provide a three-dimensional object printing system and a three-dimensional object printing method that can easily improve the printing accuracy on a three-dimensional object and easily increase productivity. [Brief description of the drawings]

[0018] [Figure 1] FIG. 1 is a configuration diagram showing a three-dimensional object printing system according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a schematic diagram of the three-dimensional object printing system shown in FIG. [Diagram 3] FIG. 1 is an explanatory diagram (part 1) showing a procedure for generating print rendering data. [Figure 4] FIG. 2 is an explanatory diagram (part 2) showing the procedure for generating print rendering data. [Diagram 5] FIG. 3 is an explanatory diagram (part 3) showing the procedure for generating print rendering data. [Figure 6] 2 is a perspective view showing a configuration example of a detection unit of the three-dimensional object printing system shown in FIG. 1. [Figure 7] 2 is a perspective view showing an example of the configuration of a printing table of the three-dimensional object printing system shown in FIG. 1. [Figure 8] This is intended to explain the procedure for generating print data. Figure 8(a) is an example in which a three-dimensional object is placed in a random orientation, and Figure 8(b) is a diagram showing how the position (x, y) and rotation angle (θ) of the three-dimensional object are determined. [Figure 9] 11 is a plan view of a printing table showing a printing example of a printing reference point. FIG. [Figure 10] 10 is a diagram showing an example of a printing reference point different from that in FIG. 9; FIG. [Figure 11] This figure uses a doll's face as an example to explain the procedure for determining the printing position by pattern matching. Figure 11(a) is a front view of a three-dimensional object illustrating detection points, and Figure 11(b) is a front view of a three-dimensional object illustrating a shadow pattern. [Figure 12] FIG. 13 is a diagram showing an example in which the contour shape of a shadow pattern obtained according to the unevenness of the surface of a doll's face is used as a detection point as a feature point. [Figure 13] 11A and 11B are diagrams illustrating a method for detecting feature points on the contour of a three-dimensional object. [Figure 14]14A is an enlarged view of a main part of the three-dimensional object before printing, and FIG. 14B is an enlarged view of a main part of the three-dimensional object after printing. [Figure 15] FIG. 1 is a schematic diagram illustrating a belt conveyor type printing table that is applied to a three-dimensional object printing system according to an embodiment of the present invention. [Figure 16] FIG. 13 is a perspective view showing another example of the configuration of the detection unit applied to the three-dimensional object printing system according to the present embodiment. [Figure 17] FIG. 1 is a schematic diagram showing a case where a two-dimensional digital camera equipped with a reduction optical system is used as detection means in this embodiment. [Figure 18] 10A and 10B are diagrams for explaining a method for determining a correction amount for a print position from a detection reference and a print reference point in the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Hereinafter, a three-dimensional object printing system and a three-dimensional object printing method according to an embodiment of the present invention will be described with reference to the drawings. In the attached drawings, the same or similar reference numerals are used for the same parts, and detailed description will be omitted. In addition, the description here is the best mode for carrying out the present invention, and the present invention is not limited to this mode.

[0020] Embodiment The configuration of a three-dimensional object printing system S1 according to this embodiment will be described with reference to FIGS.

[0021] FIG. 1 shows the overall configuration of a three-dimensional object printing system S1 according to this embodiment in functional blocks, and FIG. 2 shows a schematic configuration of the three-dimensional object printing system S1 according to this embodiment.

[0022] About the S1 3D printing system 1 and 2, this three-dimensional object printing system S1 is equipped with a printing table T on which a plurality of identical three-dimensional objects 10, 10, ... as printing targets can be placed simultaneously. Above this printing table T, there are provided detection means 101 which detects the position and orientation (rotation angle) of each of the three-dimensional objects 10, 10, ... placed on the printing table T, and a scanning print head 130 of printing means 103 which executes printing on each of the three-dimensional objects 10, 10, ... according to print data.

[0023] The three-dimensional object printing system S1 also includes a print data generation means 102 that generates print data corresponding to each of the three-dimensional objects 10, 10, ... based on the detection result by the detection means 101. Furthermore, the three-dimensional object printing system S1 also includes a control means 104 that controls the operations of the detection means 101, the print data generation means 102, and the printing means 103.

[0024] About detection method 101 Here, the detection means 101 can be composed of an optical sensor 200 such as a digital camera, a three-dimensional sensor, a contact image sensor (CIS), or a laser length measuring device, which acquires three-dimensional posture information of each three-dimensional object 10, 10, ... placed on the printing table T.

[0025] The detection means 101 includes an indication means 105 that sets a plurality of detection points in advance on the surface of the three-dimensional object 10. That is, the detection means 101 detects the positions of the detection points set by the indication means 105 for each of the three-dimensional objects 10, 10, ... in order to acquire three-dimensional posture information of each of the three-dimensional objects 10, 10, ....

[0026] The detection means 101 detects the position of a detection reference mark (reading reference point) 15 that is fixed in advance on the printing table T (details will be described later).

[0027] Regarding the control means 104 The control means 104 calculates the positions and rotation angles of each of the three-dimensional objects 10, 10, . . . on the printing table T based on the positions of the detection points detected by the detection means 101 and the positions of the detection reference marks 15.

[0028] In addition, the control means 104 can determine the posture of each of the three-dimensional objects 10, 10, ... by pattern matching based on data regarding the calculated position and rotation angle of each of the three-dimensional objects 10, 10, ... and data regarding the three-dimensional posture information of the three-dimensional object 10 that has been acquired in advance.

[0029] In this embodiment, the control means 104 can be configured by a workstation 104A or the like.

[0030] Regarding the print data generating means 102 The print data generating means 102 includes a first generating means 102A that generates first print data (drawing data) based on the posture of each of the three-dimensional objects 10, 10, ... determined by the control means 104 and drawing (printing) information to be printed on the surface of the three-dimensional object 10. The print data generating means 102 also includes a second generating means 102B that generates second print data that is optimized by performing a rotation process on the first print data according to the position and rotation angle of each of the three-dimensional objects 10, 10, ... detected by the detection means 101.

[0031] The print data generating means 102 can be configured with a workstation 104B as hardware, predetermined data processing software, and the like.

[0032] Regarding printing method 103 The printing means 103 can be configured, for example, by a flatbed type UV inkjet printer.

[0033] Here, a height information detection means may be further provided for detecting the height (thickness) of each of the three-dimensional objects 10, 10, ... placed on the printing table T. In this case, the printing data generation means 102 can correct the second printing data based on the height information of each of the three-dimensional objects 10, 10, ... detected by the height information detection means.

[0034] In addition, if the optical sensor is composed of a three-dimensional sensor such as a digital camera equipped with a laser length measuring device that obtains three-dimensional posture information of each of the three-dimensional objects 10, 10, ... placed on the printing table T, the first generation means 102A may generate first printing data based on the detection results by the three-dimensional sensor, and the second generation means 102B may generate optimized second printing data by performing a rotation process on the first printing data according to the position and rotation angle of each of the three-dimensional objects 10, 10, ...

[0035] Inspection of print results Also, the detection means 101 may detect the printing condition on the surface of each of the three-dimensional objects 10, 10, . . . , and the control means 104 may determine whether the printing is good or bad based on the detection result of the printing condition.

[0036] Regarding the processing of the first generating means 102A The process performed by the first generating means 102A will be described in detail below.

[0037] First, the first generating means 102A receives 3D CAD data having three-dimensional shape information about the three-dimensional object 10 and design data having drawing information about coloring and drawing (printing) to be applied to the surface of the three-dimensional object 10. The 3D CAD data includes posture information on the printing table T.

[0038] It should be noted that the most stable posture on the printing table T can be determined from the 3D CAD data on the operation screen of the workstation 104B constituting the first generating means 102A of the printing data generating means 102.

[0039] Next, the 3D CAD data corresponding to the orientation information of the three-dimensional object 10 on the printing table T and the design data are synthesized, and two-dimensional rendering data is extracted under the condition of a parallel light perspective image.

[0040] Thereafter, first print data is generated as drawing data from the extracted two-dimensional rendering data and the depth information corresponding to the rendering data.

[0041] More specifically, since the printing means 103 generally prints two-dimensional data on a plane, the printing characteristics for a depth away from the plane are different from the printing characteristics for printing on the plane. The depth printing characteristics different from the plane are stored in advance, and the optimal drawing data is generated from the depth information corresponding to the rendering data by referring to the stored characteristics.

[0042] For example, in the case of an inkjet printer, the printing characteristics for depth depend on the flight characteristics of the ink droplets. Therefore, in order to compensate for the disturbance in printing characteristics caused by the poor landing accuracy of ink droplets at relatively distant positions, the print rendering data is expanded to create optimal drawing data for contours with depth.

[0043] Procedure for generating print rendering data Here, a procedure for generating print rendering data in the three-dimensional object printing system S1 according to this embodiment will be described with reference to Fig. 3 to Fig. 5. Note that here, a mascot doll D1 will be exemplified as the three-dimensional object 10 to be printed.

[0044] First, as shown in FIG. 3, the orientation of mascot doll D1 (D1a to D1d) is manipulated using a pointing device such as a mouse on the operation screen 400 of the workstation 104B constituting the first generation means 102A, and the posture of mascot doll D1 is determined (part 1).

[0045] Next, as shown in FIG. 4, the 3D CAD data of the mascot doll D1 in the determined posture and design data (clothing design data in the example of FIG. 4) W1 are combined on the operation screen 400 (part 2).

[0046] In this way, as shown in FIG. 5, two-dimensional rendering data is extracted under the condition of a parallel light perspective image, and drawing data W1a is generated from this two-dimensional rendering data and the depth information corresponding to this rendering data (part 3).

[0047] Concrete examples of the detection means 101 The configuration of the detection means 101 will be specifically described below with reference to FIG.

[0048] FIG. 6 shows an example in which the detection means 101 of the three-dimensional object printing system S1 according to this embodiment is configured with a contact image sensor (CIS).

[0049] In this case, above the printing table T, the CIS 200 is arranged in a line along one direction of the printing table T (for example, the Y direction).

[0050] The CIS 200 is provided so as to be able to move in other directions (for example, the X direction) above the printing table T along a scanning rail 201, and optically scans the placement surface of the printing table T as it moves.

[0051] A scanning print head 130 is provided above the printing table T, and prints the entire surface of the printing table T while moving using a slider 301, which is a scanning means in the Y direction, and a scanning means in the X direction.

[0052] 7, for example, detection reference marks 15 detectable by the CIS 200 are attached and fixed to two diagonal corners (or four corners) of the mounting surface of the printing table T so as to protrude from the mounting surface of the printing table T in a direction closer to the detection means 101. In other words, the detection reference marks 15 are fixed so as to protrude above the table surface of the printing table T.

[0053] By fixing the detection reference mark 15 protruding in a direction closer to the detection means 101, the distance from the detection means 101 to the detection point of the detection reference mark 15 and the three-dimensional object 10 becomes closer, thereby obtaining the effect of reducing errors due to the focal depth of the optical sensor 200 of the detection means 101.

[0054] The detection reference mark 15 may be a single mark, provided that it is located at a predetermined position on the placement surface. The detection reference mark 15 may be printed by the printing means 103, but may also be located outside the printing area and may be located at a position that does not affect printing or placement of the three-dimensional object 10.

[0055] Here, when the printing means 103 is a UV inkjet printer, the print data needs to be generated so that the position of the three-dimensional object 10 on the printing table T matches the position of the three-dimensional object 10 .

[0056] The drawing (printing) position accuracy is set to a target value of 200μ based on the results of a preliminary investigation, and the position of a three-dimensional object 10 on the printing table T of the UV inkjet printer can be detected with an accuracy of 100μ, and the rotation angle with an accuracy of 1 degree.

[0057] The CIS 200 is configured with a line sensor having 17,000 pixels, and is moved along a scanning rail 201 so as to read the surface of the printing table T.

[0058] Then, through processing of the reading signal processing calculation software stored in the workstation 104B, the reference point (described later) of the three-dimensional object 10 is specified by the CIS 200, and the position and rotation angle of the three-dimensional object 10 on the printing table T are calculated from the reading results.

[0059] In addition, it is also effective to control the acceleration and deceleration of the scanning rail 201 so as to prevent errors in the results due to the influence of vibrations during reading, thereby shortening the detection (reading) time and stabilizing the reading accuracy at the same time. In this embodiment, the scanning time of the CIS 200 is set to about 1 to 4 seconds.

[0060] Furthermore, as described above, when the CIS 200 is a line sensor having 17,000 pixels, the size of the printing table T is 700 mm (Y direction)×500 mm (X direction).

[0061] The CIS 200, which moves on a plane parallel to the placement surface of the printing table T, is positioned 4 cm from the printing table T depending on the height of the three-dimensional object 10. For example, if the height of the three-dimensional object 10 is approximately 0.5 cm to 2 cm, the CIS 200 is positioned 4 cm from the printing table T.

[0062] On the other hand, when a two-dimensional digital camera equipped with a reduction optical system is used as in the example shown in FIG.

[0063] In this example, it is preferable to design the viewing angle to be 5.7 degrees or less so that the effect of a height error of 0.5 mm is within the range of a reading error of 0.05 mm. In this way, the viewing angle can be made small to reduce errors caused by the influence of the viewing angle.

[0064] Print position correction (method of calculating the print position correction value using print reference point c) A method for determining the printing position on the three-dimensional object 10 with high accuracy by providing a printing reference point c will be specifically described below.

[0065] The position information of the three-dimensional object 10 on the printing table T read by the CIS 200, an optical sensor used as the detection means 101, must be accurately matched with the virtual printing reference coordinates that determine the printing position of the printing means 103 (details will be described later).

[0066] For example, two detection reference marks 15 are attached and fixed diagonally on the placement surface of the printing table T in Fig. 6, and four detection reference marks 15 are attached and fixed in Fig. 9. In other words, the detection reference marks 15 are attached and fixed to correspond to the four corners of the printing table T, respectively.

[0067] 9, a printing reference point c is printed at a predetermined position on the printing table T (in this case, the printing sheet may be fixed on the printing table T and the printing reference point c may be printed). In order to detect the printing position, a plurality of printing reference points c are printed.

[0068] Then, as shown in FIG. 18, after printing the printing reference points c, the virtual printing coordinates of each printing reference point c on the printing table T are calculated, and the relationship with the virtual coordinates of the detection reference points c based on the detection reference marks 15 is determined.

[0069] That is, in this embodiment, based on the positional relationship between the detection reference mark 15 and the printing reference point c, the deviation between the printing target position on the virtual coordinates determined by the detection reference mark 15 and the actual printing position is calculated as the printing position correction value. Then, by reflecting the printing position correction value in the generation of the second printing data, it becomes possible to always perform printing on the three-dimensional object 10 stably.

[0070] More specifically, for example, a sheet for printing position correction is fixed to the printing table T, a printing reference point c is printed, and the positional relationship between the printed printing reference point c and the detection reference mark 15 is detected, and the deviation between the printing target position on the virtual coordinates and the actual printing position can be obtained as the printing position correction value, as described above.

[0071] The printing reference point c is printed, for example, as shown in Figures 9 and 10. That is, in Figure 9, multiple circles with the printing reference point c as their center point are printed. Also, in Figure 10, multiple prints are made of four circles with their center points at equal intervals (four locations) from the printing reference point c.

[0072] Then, as described above, the optical sensor 200 detects circles centered on these printed printing reference points c, and the center points of the circles are found using image processing such as pattern matching. The deviation between the printing target position on the virtual printing reference coordinates, which are virtual coordinates, and the actual printing position is found as the printing position correction value.

[0073] This makes it possible to match the printing reference of the printing means 103 with high accuracy with the detection reference of the detection means 101. In addition, it is possible to reflect errors in reduction ratio and orthogonality in the entire printing area from the detection result of the printing reference point c, making it possible to perform high-precision printing over the entire area of ​​the printing table T.

[0074] Although an example has been described in which the print reference point c is printed by the printing means 103, any reference point that corresponds to the print position by the printing means 103 may be used, for example, the reference point of a linear encoder that scans the print head 130 may be used.

[0075] About Shadow Detection In addition, in order to determine the position and rotation angle (rotation angle within the plane of the printing table T) of each three-dimensional object 10, 10, ... with high accuracy and in a short time from the information read by the CIS 200, for example, as shown in Figure 11, two or more characteristic points of the shadow caused by the unevenness of the surface of the three-dimensional object 10 are set as detection points P1, P2, and the detection points P1, P2 are identified by a brightness threshold value, and the position and rotation angle of the shadow pattern that matches the pre-registered contour pattern are detected.

[0076] Specifically, for example, as shown in Figure 11(a), taking the example of printing a mouth and the like on the face of a doll, which is the surface of a three-dimensional object 10, as described above, in order to obtain information regarding the shading of the doll's face (shade pattern Q) regardless of the contour information of the mascot doll D1, two shading feature points are set as detection points P1 and P2, as shown in Figure 11(b).

[0077] Then, as shown in FIG. 11C, for example, a shadow pattern Q is specified from the read information of the CIS 200 using a brightness threshold value.

[0078] Then, the identified feature points of the shadow pattern Q are superimposed on positions corresponding to the detection positions of the detection points P1 and P2 to determine the coordinate position (x, y) and rotation angle (θ) of the shadow pattern (see, for example, FIG. 8(a)).

[0079] In addition to the feature points such as P1 and the feature points on the contour line of the unevenness shown by shading, the detection points may be features of the shape of a continuous uneven contour line, instead of points. For example, according to the shape of the surface of the three-dimensional object 10 shown in Fig. 11(a), the dashed lines of the shaded contour curve due to the unevenness detected on the surface of the three-dimensional object 10 are detected as shown in Fig. 12(a), and the contour lines (solid lines) to be detected are specified as shown in Fig. 12(b), and the solid contour lines are connected to automatically calculate a closed area (thick solid line) and determine the coordinates of its center of gravity as shown in Fig. 12(c).

[0080] Alternatively, the feature points of the shadows may be combined as detection points, and the feature points of the contours may be combined as detection points.

[0081] In the present invention, detecting the position of a detection point set on the surface of a three-dimensional object 10 does not necessarily mean detecting the position of a detection point set as a characteristic point on the contour line of the unevenness indicated by shading according to the surface shape of the three-dimensional object 10 described above. For example, as shown in Figure 13, it is also possible to detect a characteristic point on the contour of the three-dimensional object 10, and a combination of these methods can also be used.

[0082] In this embodiment, in order to detect the position (x, y) and orientation (rotation angle θ within the plane of the printing table T) of the three-dimensional object 10 on the printing table T, two or more detection points P1, P2 are set.

[0083] For example, in the example shown in FIG. 8(a), five to six three-dimensional objects 10 are placed in each of the areas A1 to A4 of the printing table T in random orientations.

[0084] Here, taking area A4 as an example, for each of the three-dimensional objects 10a to 10e, as shown in FIG. 8(b), the position (x, y) and rotation angle (θ) are determined based on the detection reference mark 15 and, for example, the shadow pattern Q shown in FIG. 11(b).

[0085] In this way, the information on the position (x, y) and rotation angle (θ) of each of all three-dimensional objects 10, 10, ... placed on the printing table T is transferred to the first generation means 102A, which generates the first printing data (drawing data).

[0086] As a result, in the second generating means 102B, the first print data is subjected to a rotation process in accordance with the position (x, y) and rotation angle (θ) of each of the three-dimensional objects 10, 10, . . . to generate optimized second print data.

[0087] Also, in the example shown in Figure 8(a), each three-dimensional object 10, 10, ... is placed within each area A1 to A4 of the printing table T, but even in the case of a three-dimensional object 10 placed in a position spanning several areas A1 to A4, it is possible to similarly perform each process by combining the areas.

[0088] Furthermore, even when there are multiple types of three-dimensional objects 10 and different drawing data exists for each type of three-dimensional object 10, the application of the present invention makes it possible to perform printing with a similar high degree of accuracy.

[0089] (Shade detection) Print example For example, assume that a plurality of three-dimensional objects 10, 10, . . . are placed on a printing table T as shown in FIG.

[0090] In this case, as long as each of the three-dimensional objects 10, 10, ... can maintain a predetermined posture on the printing table T, the rotation angle and position within the plane of the printing table T are free. In addition, there is no limit to the number of the three-dimensional objects 10, 10, ... as long as they are within the range that can be placed on the printing table T.

[0091] Then, the position and rotation angle of each of the three-dimensional objects 10, 10, ... are detected by the above-mentioned method, and the printing means 103 is driven by the printing data generated based on the results, thereby executing printing on each of the three-dimensional objects 10, 10, .... As a result, as shown in Fig. 14(b), a plurality of printed objects 10A on which the predetermined printing has been performed well can be obtained.

[0092] As described above, according to the three-dimensional object printing system S1 of this embodiment, the trial and error required to obtain a printed object can be eliminated, and the printing accuracy of the three-dimensional object 10 can be easily improved, thereby easily increasing productivity.

[0093] That is, based on the positional relationship between the detection reference mark 15 and the printing reference point c, the deviation between the printing target position on the virtual coordinates determined by the detection reference mark 15 and the actual printing position is calculated as a printing position correction value, and is reflected in the generation of the second printing data.

[0094] This makes it possible to easily ensure the printing accuracy of the three-dimensional object 10 regardless of the position of the three-dimensional object 10 placed on the printing table T, without having to adjust the printing data or the printing surface (printing surface) of the detection reference point c for each three-dimensional object 10 to be printed.

[0095] Furthermore, by using the shadows that appear on the surface of the three-dimensional object 10 as the multiple detection points P1, P2 set on the surface of the three-dimensional object 10, it is possible to improve the deterioration of printing quality caused by the misalignment between the unevenness of the surface of the three-dimensional object 10 and the printing position when the contour of the three-dimensional object 10 is used.

[0096] In other words, by using shading, the problem of printing position errors in the shaded portion caused by the relative positional relationship between the contour and the shaded position varying depending on the three-dimensional posture is also eliminated, compared to the case where the contour of the three-dimensional object 10 is used.

[0097] Furthermore, when printing a large number of three-dimensional objects 10, 10, ... simultaneously, the calculation time required to obtain the three-dimensional information of each of the placed three-dimensional objects 10, 10, ... and generate print data according to the surface shape can become long, resulting in reduced productivity. However, with this method, detection points based on shading information are detected and the positions of the unevenness on the surface of the three-dimensional object 10 are determined, making it possible to obtain a printing system for three-dimensional objects 10 with short calculation times and high productivity.

[0098] Furthermore, it is possible to perform high-precision, high-definition printing on a plurality of three-dimensional objects 10, 10, ... without using a printing jig, thereby reducing printing costs. Note that even when a printing jig is used, the present invention is effective because it has the effect of eliminating printing defects caused by errors in the placement of the printing jig on the printing table T and deviations in the position and rotation angle of the three-dimensional object 10 on the printing jig.

[0099] Other embodiment (1) About the conveyor belt In addition, in the three-dimensional object printing system S1 according to this embodiment, as shown in FIG. 15, for example, the printing table T can be configured as a belt conveyor 700 having a caterpillar-like belt or the like capable of placing multiple three-dimensional objects 10, 10, ... and moving from the upstream side to the downstream side.

[0100] Other embodiment (2) Printing table scanning mode Also, as shown in FIG. 16, for example, the detection means 101 may be configured such that a printing table T is movable in the direction of the arrow X on a support stand S along a scanning rail 501, and above the printing table T, a CIS 200 whose position is fixed, and a scanning print head 130 which is movable in the direction of the arrow Y by a Y slider 302.

[0101] Even when the detection means 101 has such a configuration, the three-dimensional object printing system S1 of this embodiment can obtain a plurality of printed objects 10A on which the predetermined printing has been performed satisfactorily.

[0102] Other embodiment (3) Regarding the third generation method It is also possible to provide the print data generation means 102 with a third generation means for generating optimized print data based on the flight angle of the ink particles (ink droplets) ejected from the scanning print head 130 and the shape of the printing surface of each three-dimensional object 10, 10, ....

[0103] This allows ink droplets ejected from the scanning print head 130 to land in desired positions, improving printing accuracy.

[0104] Alternatively, the pattern of change in the shadow of the three-dimensional object 10 may be acquired and stored in a database in advance. This allows the solid angle (three-dimensional posture) of each of the three-dimensional objects 10, 10, . . . to be detected with higher accuracy.

[0105] Other embodiment (4) About the modified version Although the present invention has been specifically described above based on the embodiments, the embodiments disclosed in this specification are illustrative in all respects and should not be considered to be limited to the disclosed technology. In other words, the technical scope of the present invention should not be interpreted restrictively based on the description in the embodiments, but should be interpreted according to the claims, and includes technologies equivalent to the technologies described in the claims and all modifications within the scope of the claims.

[0106] For example, the printing means 103 is not limited to a UV inkjet printer, and printers using various printing methods can be applied.

[0107] Furthermore, the control means 104 is not limited to a workstation, and a personal computer or the like may be used.

[0108] Furthermore, the shape of the printing reference points c is not limited to a circle, but may be an intersection of multiple lines or the center of a polygon. The arrangement of the printing reference points c is not necessarily limited to a regular arrangement. [Explanation of symbols]

[0109] S1 3D Printing System 10 Three-dimensional object 15 Detection reference mark (detection reference) 101 Detection means 102 Print data generating means 102A First generation means 102B Second generation means 103 Printing means 104 Control Means 105 Instruction means 130 Scanning Print Head 200 Optical Sensor T Printing Table c Print reference point

Claims

1. A printing table on which a three-dimensional object to be printed is placed; a detection standard fixed on said printing table; a detection means for detecting the position of the detection reference and the positions of a plurality of detection points set on the surface of the three-dimensional object; a print data generating means for generating print data corresponding to the three-dimensional object; a printing means for executing printing on the three-dimensional object using the print data generated by the print data generating means; a control means for controlling the operations of the detection means, the print data generation means, and the printing means; Equipped with The printing data generation means calculates a correction value for the printing position based on the position of the detection reference and the printing reference point detected by the detection means, reflects the calculated correction value in the calculation of the position and rotation angle of the three-dimensional object, and generates the printing data according to the position and rotation angle of the three-dimensional object with the correction value reflected.

2. The three-dimensional object printing system according to claim 1 , wherein the printing reference point is printed in order to detect the printing position.

3. The three-dimensional object printing system according to claim 1, characterized in that the detection means includes an instruction means for presetting the detection point according to the shading of the three-dimensional object in order to obtain information regarding the shading caused by unevenness on the surface of the three-dimensional object.

4. 2. The three-dimensional object printing system according to claim 1, wherein the detection reference is fixed to protrude from the printing table in a direction closer to the detection means.

5. a detection step of detecting the positions of detection points set on a surface of a three-dimensional object placed on a printing table and the position of a detection reference fixed to the printing table; a calculation step of calculating a position and a rotation angle of the three-dimensional object based on the detected positions of the detection reference and the detection point; a control process of calculating a correction value for the print position based on the detected position of the detection reference and the print reference point, reflecting the calculated correction value in calculation of the position and rotation angle of the three-dimensional object, and controlling generation of print data according to the position and rotation angle of the three-dimensional object reflected with the correction value; a generating step of generating print data corresponding to the three-dimensional object based on the position and rotation angle of the three-dimensional object to which the correction value is reflected; a printing step of executing printing on the three-dimensional object using the generated print data; A three-dimensional object printing method comprising:

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