JP2025051088A - Three-dimensional object printing system and three-dimensional object printing method - Google Patents

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

The present invention relates to a three-dimensional object printing system and a three-dimensional object printing method.

Conventionally, there are known inkjet printers and printing methods using the same that can print images on the curved print surface of three-dimensional media (three-dimensional objects) in a manner that makes the images appear to have a substantially uniform density (see, for example, Patent Document 1).

In addition, a three-dimensional object printing system and a three-dimensional object printing method have been proposed that do not require rotational control of the three-dimensional object and can perform high-resolution printing without using a fixed jig (see, for example, Patent Documents 2 and 3).

JP 2006-335019 A JP 2015-134410 A JP 2018-187915 A

Patent Document 1 requires rotation control 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.

On the other hand, in Patent Document 3, multiple detection standards are printed on the printing table to improve the error between the printing position and the detection standard mark. With the technology in Patent Document 3, it is possible to obtain stable, accurate printing with good productivity compared to other technologies.

However, with this technology, a constant relationship between the detection standard and the printing position where the three-dimensional object is printed is necessary to maintain printing position accuracy, but there is a problem with printing position errors that depend on the repeatability of the printing position. In particular, errors that occur after continuing printing for a long period of time or pausing printing for a certain period of time are problematic.

One way to solve 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, which are printing means with excellent productivity, there is a drawback in that the distance from the inkjet head (scanning print head) when printing a three-dimensional object placed on the print table to the print table on which the detection standard is printed is large, making it difficult to print the detection standard mark clearly.

However, in conventional three-dimensional object printing systems and methods, the position of a three-dimensional object is identified based on multiple 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 can affect the identification of the object's position.

In other words, when a 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 a detection point set on the surface of the three-dimensional object for detecting the orientation of the three-dimensional object will differ 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, the difference in distance can easily lead to problems such as errors in detecting the positional relationship between the detection reference mark and the detection point.

To avoid such errors, it is possible to print a detection reference mark at a position approximately equal to the distance (height) from the placement surface of the printing table to the detection point on the three-dimensional object.

However, the height of the detection reference mark must be adjusted for each three-dimensional object to be printed, which creates problems such as a hindrance to increasing productivity.

Even if 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 the deterioration over time of the print being dirty or rubbed off, which can cause errors in the detection standard.

In view of the above circumstances, the present invention aims to provide a three-dimensional object printing system and a three-dimensional object printing method that can easily improve the printing accuracy on three-dimensional objects and easily increase productivity.

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 multiple 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 print means for executing 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 print means, and 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.

The three-dimensional object printing method according to 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 positions 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 reflecting the correction value, 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 reflecting the correction value, and a printing step of executing printing on the three-dimensional object using the generated print data.

The present invention provides a three-dimensional object printing system and a three-dimensional object printing method that can easily improve the printing accuracy on three-dimensional objects and increase productivity.

FIG. 1 is a configuration diagram showing a three-dimensional object printing system according to an embodiment of the present invention. FIG. 2 is a schematic diagram of the three-dimensional object printing system shown in FIG. 1 . FIG. 11 is an explanatory diagram (part 1) showing a procedure for generating print rendering data. FIG. 2 is an explanatory diagram (part 2) showing the procedure for generating print rendering data. FIG. 3 is an explanatory diagram (part 3) showing the procedure for generating print rendering data. FIG. 2 is a perspective view showing a configuration example of a detection unit of the three-dimensional object printing system shown in FIG. 1 . FIG. 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 . This is intended to explain the procedure for generating print data, with Figure 8(a) being an example in which a three-dimensional object is placed in a random orientation, and Figure 8(b) being a diagram showing how the position (x, y) and rotation angle (θ) of the three-dimensional object are determined. 11 is a plan view of a printing table showing a printing example of a printing reference point. FIG. FIG. 10 is a diagram showing an example of a printing reference point different from that shown in FIG. 9 . This is to explain the procedure for determining the printing position by pattern matching, using a doll's face as an example, and FIG. 11(a) is a front view of a three-dimensional object illustrating detection points, and FIG. 11(b) is a front view of a three-dimensional object illustrating a shadow pattern. 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. 11A and 11B are diagrams illustrating a method for detecting feature points on the contour of a three-dimensional object. 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. 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. 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. FIG. 1 is a schematic diagram showing a case where a two-dimensional digital camera equipped with a reduction optical system is used as a detection means in this embodiment. 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.

Below, 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. Note that in the attached drawings, identical parts are given the same or similar reference numerals, and detailed explanations will be omitted. Also, the description here is the best mode for carrying out the present invention, and the present invention is not limited to this mode.

1 and 2, the configuration of a three-dimensional object printing system S1 according to this embodiment will be described.

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

1 and 2, the 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 the printing table T, there are provided detection means 101 for detecting 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 a printing means 103 for executing printing on each of the three-dimensional objects 10, 10, ... according to print data.

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 results by the detection means 101. It 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.

Regarding the detection means 101, 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.

The detection means 101 includes a designation means 105 that sets a number of detection points in advance on the surface of the three-dimensional object 10. In other words, the detection means 101 detects the positions of the detection points set by the designation means 105 for each of the three-dimensional objects 10, 10, ... in order to obtain three-dimensional orientation information for each of the three-dimensional objects 10, 10, ....

The detection means 101 is also configured to detect the position of a detection reference mark (reading reference point) 15 that is pre-fixed on the printing table T (details will be described later).

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.

The control means 104 can also 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 previously acquired.

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

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.

The print data generation means 102 can be configured with a workstation 104B as hardware and specific data processing software, etc.

Regarding the Printing Unit 103 The printing unit 103 can be configured, for example, by a flatbed type UV inkjet printer.

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.

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

Regarding inspection of the printing results, 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 the quality of the printing based on the detection results of the printing condition.

Processing by First Generation Means 102A The processing by first generation means 102A will be described in detail below.

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 regarding coloring and drawing (printing) to be applied to the surface of the three-dimensional object 10. The 3D CAD data includes orientation information on the printing table T.

In addition, 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 generation means 102A of the print data generation means 102.

Next, the 3D CAD data corresponding to the orientation information of the three-dimensional object 10 on the printing table T is combined with the design data, and two-dimensional rendering data is extracted under parallel light perspective image conditions.

After this, the first print data is generated as drawing data from the extracted two-dimensional rendering data and the depth information corresponding to the rendering data.

More specifically, since the printing means 103 generally prints two-dimensional data on a plane, the printing characteristics for depths away from the plane are different from the printing characteristics on the plane. These depth printing characteristics that differ from the plane are stored in advance, and the stored characteristics are referenced to generate optimal drawing data from the depth information that corresponds to the rendering data.

For example, in the case of an inkjet printer, the printing characteristics with respect to depth depend on the flight characteristics of the ink droplets. Therefore, to compensate for the disturbance in printing characteristics caused by 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.

3 to 5, a procedure for generating print rendering data in the three-dimensional object printing system S1 according to the present embodiment will be described. Note that, in this example, a mascot doll D1 is used as an example of the three-dimensional object 10 to be printed.

First, as shown in FIG. 3, the orientation of mascot doll D1 (D1a to D1d) is determined by operating a pointing device such as a mouse on the operation screen 400 of the workstation 104B constituting the first generating means 102A (part 1).

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

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).

Concrete Example of Detection Means 101 The configuration of the detection means 101 will be specifically described below with reference to FIG.

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

In this case, the CIS 200 is arranged in a line above the printing table T along one direction of the printing table T (e.g., the Y direction).

The CIS 200 is arranged so that it can move in other directions (e.g., the X direction) above the printing table T along the scanning rail 201, and optically scans the support surface of the printing table T as it moves.

A scanning print head 130 is provided above the print table T, and prints the entire surface of the print 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.

On the other hand, as shown in FIG. 7, for example, detection reference marks 15 that can be detected by the CIS 200 are attached and fixed to two diagonal corners (or four corners) of the mounting surface of the printing table T, protruding 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.

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

The detection reference mark 15 may be located at a specific position on the placement surface, and may be singular. 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 in a position that does not affect the printing or placement of the three-dimensional object 10.

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

The target drawing (printing) position accuracy is set at 200μ based on the results of a preliminary investigation, and the position of the 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.

The CIS 200 is also composed of a line sensor with 17,000 pixels, and is moved along the scanning rail 201 to read the surface of the printing table T.

Then, the CIS 200 specifies the reference point (described later) of the three-dimensional object 10, and calculates the position and rotation angle of the three-dimensional object 10 on the printing table T from the results of the reading, through processing of the reading signal processing calculation software stored in the workstation 104B.

It is also effective to control the acceleration and deceleration of the scanning rail 201 to prevent errors in the results due to the effects of vibrations during reading, thereby shortening the detection (reading) time and stabilizing the reading accuracy. In this embodiment, the scanning time of the CIS 200 is set to about 1 to 4 seconds.

As described above, when the CIS 200 is a line sensor with 17,000 pixels, the size of the printing table T is 700 mm (Y direction) x 500 mm (X direction).

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, it is positioned 4 cm from the printing table T.

On the other hand, when using a two-dimensional digital camera equipped with a reduction optical system, as in the example shown in Figure 17, the detection means 200 is positioned approximately 80 cm from the printing table T.

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.

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

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).

For example, two detection reference marks 15 are attached and fixed diagonally on the mounting 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.

Then, a printing reference point c is printed at a predetermined position on the printing table T shown in FIG. 9 (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, multiple printing reference points c are printed.

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.

In other words, 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.

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

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 with four circles with center points at equal intervals (four locations) from the printing reference point c.

Then, as described above, a circle centered on these printed printing reference points c is detected by the optical sensor 200, and the center point of the circle is determined using image processing such as pattern matching, and the deviation between the printing target position on the virtual printing reference coordinates, which are virtual coordinates, and the actual printing position is determined as the printing position correction value.

This allows the printing reference of the printing means 103 to match the detection reference of the detection means 101 with high accuracy. In addition, the detection results of the printing reference point c can also reflect errors in reduction ratio and straightness in the entire printing area, making it possible to print with high accuracy over the entire area of the printing table T.

The above describes an example in which the printing reference point c is printed by the printing means 103, but any reference point that corresponds to the printing position by the printing means 103 can be used, for example, the reference point of a linear encoder that scans the print head 130.

Regarding shadow detection, 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.

Specifically, for example, as shown in FIG. 11(a), in the case where a mouth and the like are printed on the face of a doll, which is the surface of a three-dimensional object 10, as described above, in order to obtain information on the shading of the doll's face (shading pattern Q) without relying on the outline information of the mascot doll D1, two characteristic points of the shading are set as detection points P1 and P2, as shown in FIG. 11(b).

Then, as shown in FIG. 11(c), for example, a shadow pattern Q is identified from the read information of the CIS 200 using a brightness threshold.

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)).

In addition to the feature points such as P1 and the feature points on the uneven contour line shown by shading, the detection points may be features of a continuous uneven contour line shape rather than points. For example, according to the surface shape of the three-dimensional object 10 shown in FIG. 11(a), as shown in FIG. 12(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, and the contour lines (solid lines) that specify the detection among them 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 its center of gravity coordinates as shown in FIG. 12(c).

Alternatively, the feature points of the shadows can be combined as detection points, and the feature points of the contours can be combined as detection points.

In the present invention, detecting the position of a detection point set on the surface of a three-dimensional object 10 does not only mean detecting the position of a detection point set as a feature point on the contour line of the unevenness indicated by shading according to the surface shape of the three-dimensional object 10 described above, but also means detecting a feature point on the contour of the three-dimensional object 10, for example, as shown in FIG. 13, or a combination of these methods can be used.

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

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

Here, taking area A4 as an example, as shown in FIG. 8(b), for each of the three-dimensional objects 10a to 10e, 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).

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

As a result, in the second generation means 102B, the first print data is rotated according to the position (x, y) and rotation angle (θ) of each three-dimensional object 10, 10, ... to generate optimized second print data.

In the example shown in FIG. 8(a), each three-dimensional object 10, 10, ... is placed in each area A1 to A4 of the printing table T, but even if a three-dimensional object 10 is placed in a position that spans several areas A1 to A4, the same is possible by combining the areas of each process.

Furthermore, even if 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 similar high precision.

(Shadow 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.

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 quantity (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.

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 performing printing on each of the three-dimensional objects 10, 10, .... As a result, it is possible to obtain a plurality of printed objects 10A on which the specified printing has been performed satisfactorily, as shown in FIG. 14(b).

As described above, the three-dimensional object printing system S1 according to this embodiment can easily improve the accuracy of printing on the three-dimensional object 10, such as by eliminating the need for trial and error to obtain a printed object, and can easily increase productivity.

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.

This makes it possible to easily ensure the accuracy of printing on 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 print data or the print surface (print surface) of the detection reference point c for each three-dimensional object 10 to be printed.

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

In other words, by using shading, the problem of printing position errors in the shaded area caused by the relative positional relationship between the contour and the shaded position differing depending on the three-dimensional posture is also eliminated, compared to when the contour of the three-dimensional object 10 is used.

In addition, when printing multiple three-dimensional objects 10, 10, ... simultaneously, the calculation time required to obtain the three-dimensional information of each placed three-dimensional object 10, 10, ... and generate print data according to the surface shape can be long, resulting in reduced productivity. However, with this method, detection points based on shading information are detected to determine the positions of the unevenness on the surface of the three-dimensional object 10, so calculation times are short and a highly productive printing system for three-dimensional objects 10 can be obtained.

In addition, it is possible to perform high-precision, high-definition printing on multiple 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.

Other embodiment (1)
Regarding the belt conveyor: 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 equipped with a caterpillar-like belt that can place a plurality of three-dimensional objects 10, 10, ... and move from the upstream side to the downstream side.

Other embodiment (2)
Regarding the scanning form of the printing table: Also, as shown in FIG. 16, for example, the detection means 101 may be configured such that the 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, the detection means 101 may include 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.

Even when the detection means 101 is configured in this way, the three-dimensional object printing system S1 of this embodiment can obtain multiple printed objects 10A on which the specified printing is performed satisfactorily.

Other embodiment (3)
Regarding the third generation means: 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 of the three-dimensional objects 10, 10, ....

This allows the ink droplets ejected from the scanning print head 130 to land at the desired position, improving printing accuracy.

In addition, the pattern of changes 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 three-dimensional object 10, 10, ... to be detected with higher accuracy.

Other embodiment (4)
Regarding Modifications Although the present invention has been specifically described 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.

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

Furthermore, the control means 104 is not limited to a workstation, but may be a personal computer or the like.

The print reference point c does not have to be a circle, but may be an intersection of multiple lines or the center of a polygon. The arrangement of the print reference points does not necessarily have to be regular.

S1 Three-dimensional object printing system 10 Three-dimensional object 15 Detection reference mark (detection reference)
101 Detection means 102 Print data generation 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 Print table c Print reference point

Claims (5)

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. The three-dimensional object printing system according to claim 1, characterized in that the printing reference point is printed in order to detect the printing position. 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 the unevenness of the surface of the three-dimensional object. The three-dimensional object printing system according to claim 1, characterized in that the detection reference is fixed and protrudes from the printing table in a direction closer to the detection means. 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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