Method for measuring the circumference of printers and three-dimensional objects
The printer measures the circumference of cylindrical objects by recording rotational positions, addressing user-dependent diameter measurement inaccuracies and ensuring precise printing.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- ROLAND DG CORP
- Filing Date
- 2024-12-26
- Publication Date
- 2026-07-08
Smart Images
Figure 2026113808000001_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a printer capable of printing on a cylindrical three-dimensional object and a method for measuring the circumference of a cylindrical three-dimensional object.
Background Art
[0002] Printers for printing on the outer peripheral surface of a cylindrical three-dimensional object have been conventionally known. For example, Patent Document 1 discloses an inkjet printer including a three-dimensional object support device that supports and rotates a cylindrical three-dimensional object, and a recording head provided on a carriage that moves above the three-dimensional object support device. The inkjet printer described in Patent Document 1 includes a three-dimensional object diameter spin box for designating the diameter of a three-dimensional object. The inkjet printer described in Patent Document 1 is configured to set a use nozzle range based on the input diameter of a three-dimensional object so that the distance between the recording head and the three-dimensional object is within a range appropriate for ink flight.
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] As described in Patent Document 1, in a printer for printing on the outer peripheral surface of a cylindrical three-dimensional object, it is necessary to know the circumference of the outer peripheral surface of the three-dimensional object. In the inkjet printer described in Patent Document 1, the diameter of a three-dimensional object is measured by a user and input into the inkjet printer. However, the measurement accuracy of the diameter of a three-dimensional object depends on the measurement skill of the user, and there may also be a mistake of inputting an incorrect diameter.
[0005] The present invention has been made in view of the above, and its object is to provide a printer capable of measuring the circumference of a cylindrical three-dimensional object to be printed on. It also aims to provide a method for measuring the circumference of a cylindrical three-dimensional object to be printed on using a printer. [Means for solving the problem]
[0006] The printer disclosed herein comprises a rotating device for supporting a cylindrical three-dimensional object and rotating it about an axis; an ink head provided opposite the rotating device for ejecting ink onto the outer surface of the three-dimensional object supported by the rotating device; a detection device capable of detecting the rotational position of the rotating device; and a control device. The control device includes a print control unit that controls the rotating device to rotate the three-dimensional object, ejects the ink from the ink head, and prints an image based on image data onto the outer surface of the three-dimensional object. The control device further includes a rotation control unit that controls the rotating device to rotate the three-dimensional object; a first recording unit that records the rotational position of the rotating device when the three-dimensional object is at the starting point of rotation; a second recording unit that records the rotational position of the rotating device when the three-dimensional object has been rotated and returned to the starting point of rotation; and a first calculation unit that determines the circumference of the outer surface of the three-dimensional object based on the rotational position recorded in the first recording unit and the rotational position recorded in the second recording unit.
[0007] A method for measuring the circumference of a three-dimensional object disclosed herein is a method for determining the circumference of the outer surface of a three-dimensional object using a printer for printing three-dimensional objects, the printer comprising: a rotating device for supporting a cylindrical three-dimensional object and rotating it around an axis; an ink head for ejecting ink onto the outer surface of the three-dimensional object supported by the rotating device; and a detection device capable of detecting the rotational position of the rotating device, the method comprising: a step of supporting the three-dimensional object with the rotating device; a step of determining the starting point of the rotation of the three-dimensional object by the rotating device; a step of recording the rotational position of the rotating device when the three-dimensional object is at the starting point based on the detection of the detection device; a step of driving the rotating device to rotate the three-dimensional object from the starting point; a step of recording the rotational position of the rotating device when the three-dimensional object has rotated back to the starting point; and a step of determining the circumference of the outer surface of the three-dimensional object based on the rotational position at the starting point and the rotational position when it has returned to the starting point.
[0008] According to the above printer, the circumference of the outer surface of a three-dimensional object can be determined based on the rotational position of the rotating device at the starting point of the three-dimensional object and the rotational position of the rotating device when the three-dimensional object returns to its starting point. Similarly, the circumference of the outer surface of a three-dimensional object can also be determined using the above method for measuring the circumference of a three-dimensional object, by using the printer. [Brief explanation of the drawing]
[0009] [Figure 1] This is a perspective view of a printer according to one embodiment. [Figure 2] This is a perspective view showing the internal structure of the printer. [Figure 3] This is a plan view showing the internal structure of the printer. [Figure 4] This is a perspective view of a rotating device. [Figure 5] This is a block diagram of a printer. [Figure 6] This is a schematic plan view of the printed material with the mark printed on it. [Figure 7] This is a flowchart related to printing the mark. [Figure 8] This is a flowchart relating to the measurement of the circumference of the material to be printed and the correction of the rotation amount of the rotating device. [Figure 9] This is a block diagram of a printer according to a modified example of the first embodiment. [Figure 10] This is a schematic perspective view showing the upper structure of the rotating device. [Figure 11] This is a block diagram of the printer according to the second embodiment. [Figure 12] This flowchart shows an example of measuring the circumference of a printed object according to the second embodiment. [Figure 13] This is a block diagram of the printer according to the third embodiment. [Figure 14] This is a schematic plan view of the printed material with the correction pattern printed on it. [Figure 15] This flowchart shows an example of perimeter correction for printed materials. [Figure 16] This is a plan view schematically illustrating other correction patterns. [Modes for carrying out the invention]
[0010] Hereinafter, embodiments of the printer according to the present invention will be described with reference to the drawings. It should be noted that the embodiments described herein are not intended to particularly limit the present invention. Furthermore, the same reference numerals are used for components and parts that perform the same function, and redundant explanations are omitted or simplified as appropriate.
[0011] [First Embodiment] [Printer configuration] FIG. 1 is a perspective view showing a printer 10 according to an embodiment. FIG. 2 is a perspective view showing the internal structure of the printer 10. FIG. 3 is a plan view showing the internal structure of the printer 10. In the drawings, the reference signs F, Rr, L, R, U, and D indicate the front, rear, left, right, top, and bottom of the printer 10, respectively. Also, the reference signs X, Y, and Z indicate the sub-scanning direction, main-scanning direction, and vertical direction, respectively. The main-scanning direction Y is, here, the left-right direction. The sub-scanning direction X is, here, the front-rear direction. The main-scanning direction Y, sub-scanning direction X, and vertical direction Z are orthogonal to each other. However, these directions are merely defined for convenience of explanation and do not limit the installation mode of the printer 10 in any way.
[0012] The printer 10 according to this embodiment is an inkjet UV printer. However, the printing method of the printer 10 is not particularly limited. The printer 10 may be, for example, a dot impact printer, or may be a laser printer or a thermal printer.
[0013] The printer 10 according to this embodiment includes a rotating device 80 (see FIG. 4) that supports a cylindrical three-dimensional object and rotates it around an axis. The printer 10 can perform printing on the outer peripheral surface of the cylindrical printing object 5 (see FIG. 4) using the rotating device 80. Here, the rotating device 80 is configured to be detachable from the printer 10. The printer 10 according to this embodiment is also configured to be able to perform printing on the surface of other shaped printing objects that do not require rotation. However, the printer 10 may be a printer dedicated to cylindrical three-dimensional objects.
[0014] The cylindrical printing object 5 includes, for example, a slightly flattened substantially cylindrical three-dimensional object that can be rotated by a rotating roller without slipping or separating. The cylindrical printing object 5 also includes a multi-stage cylindrical three-dimensional object having a portion with a different diameter from others. The cylindrical printing object 5 also includes a three-dimensional object with a part of its outer peripheral surface missing (for example, a D cut is formed).
[0015] As shown in Figure 2, the printer 10 comprises a base member 20, a main body case 30 (see Figure 1) attached to the base member 20, a main body frame 35 attached to the base member 20, a plurality of ink heads 40, a light irradiation device 50, a carriage 60 holding the plurality of ink heads 40 and the light irradiation device 50, a carriage moving device 65, a table unit 70, a table moving device 75, a rotating device 80 (see Figure 4), a motor encoder 130 (see Figure 4) for detecting the rotational position of the rotating device 80, a sensor 140 for detecting a mark 6 (described later, see Figure 6) printed on the material to be printed 5, and a control device 200 (see Figure 5).
[0016] As shown in Figure 2, the base member 20 includes a bottom wall 21 that constitutes the bottom surface, a left upper wall 22 positioned above the left portion of the bottom wall 21, a right upper wall 23 positioned above the right portion of the bottom wall 21, a left side wall 24 connecting the bottom wall 21 and the left upper wall 22 and extending in the vertical direction Z, and a right side wall 25 connecting the bottom wall 21 and the right upper wall 23 and extending in the vertical direction Z. The portion between the left upper wall 22 and the right upper wall 23 is a recess 20a extending in the sub-scanning direction X.
[0017] The base member 20 supports the main body case 30. As shown in Figure 1, a front cover 31 is provided in the center of the front of the main body case 30. The front cover 31 is configured to open and close relative to the main body case 30. The front cover 31 is provided with a window 31a. The window 31a is formed, for example, from a transparent acrylic plate. The operator can see inside the main body case 30 through the window 31a.
[0018] As shown in Figure 2, the main frame 35 is provided on the rear portion of the base member 20. The main frame 35 is supported by the upper left wall 22 and the upper right wall 23 of the base member 20. The main frame 35 extends in the main scanning direction Y and the vertical direction Z. In the central part of the main scanning direction Y of the main frame 35, an opening 35a is formed that is configured to allow the table unit 70 to pass through and penetrates in the sub-scanning direction X. The portion of the main frame 35 above the opening 35a extends in the main scanning direction Y so as to connect the left and right portions of the opening 35a.
[0019] The table unit 70 supports the cylindrical workpiece 5 via a rotating device 80. When printing on the cylindrical workpiece 5, the rotating device 80 (see Figure 4) on which the workpiece 5 is placed is mounted on the table 71. However, when printing on a workpiece that does not require rotation, the workpiece is mounted on the table 71. The table unit 70 comprises a table 71 on which the workpiece or the rotating device 80 is mounted, and a table lifting device 72 that supports the table 71 so that it can move vertically in the Z direction.
[0020] As shown in Figure 2, the table 71 is positioned below the upper end of the opening 35a of the main frame 35. The table 71 is positioned below the ink head 40 and the light irradiation device 50. The table 71 is located at the upper end of the table lifting device 72.
[0021] The table moving device 75 moves the table unit 70 in the sub-scanning direction X. As shown in Figure 3, the table moving device 75 comprises a pair of left and right slide rails 76L and 76R, a pair of front and rear pulleys 77F and 77Rr, an endless belt 78, and a drive motor 79. The left slide rail 76L and the right slide rail 76R are provided on the left wall 24 and the right wall 25 of the base member 20, respectively. The left slide rail 76L and the right slide rail 76R extend in the sub-scanning direction X. The table unit 70 is configured to be movable in the sub-scanning direction X along the left slide rail 76L and the right slide rail 76R.
[0022] As shown in Figure 3, the front pulley 77F is located on the front portion of the bottom wall 21 of the base member 20. The rear pulley 77Rr is located on the rear portion of the bottom wall 21. The belt 78 is wrapped around the front pulley 77F and the rear pulley 77Rr. A drive motor 79 is connected to the rear pulley 77Rr. However, the drive motor 79 may also be connected to the front pulley 77F. When the drive motor 79 is driven, the rear pulley 77Rr rotates, and the belt 78 travels between the front pulley 77F and the rear pulley 77Rr. The table lifting device 72 (see also Figure 2) is attached to the belt 78. Therefore, when the belt 78 travels due to the drive of the drive motor 79, the table unit 70 moves in the sub-scanning direction X along the left and right slide rails 76L and 76R.
[0023] The carriage 60 is positioned opposite the table 71. The carriage 60 is located above the table unit 70. The carriage 60 is equipped with multiple ink heads 40 and light irradiation devices 50.
[0024] Multiple ink heads 40 are positioned opposite the table 71 of the table unit 70. When the rotating device 80 is mounted on the table 71, the multiple ink heads 40 face the rotating device 80 and eject ink onto the outer surface of the workpiece 5 supported by the rotating device 80. In this case, each of the multiple ink heads 40 ejects ink downwards. Multiple ink heads 40 are positioned on the lower surface of the carriage 60. Multiple ink heads 40 are positioned above the table unit 70. As shown in Figure 3, the multiple ink heads 40 are arranged in the main scanning direction Y. However, the number of ink heads 40 may be one. Each ink head 40 is shaped such that the length in the sub-scanning direction X is longer than the length in the main scanning direction Y. Each ink head 40 is arranged in the sub-scanning direction X and has multiple nozzles (not shown) that eject ink. In this embodiment, the ink ejected from the nozzles of the ink heads 40 is a photocurable ink. The photocurable ink is, for example, an ultraviolet curing ink. UV-curing inks have the property of hardening when exposed to ultraviolet light.
[0025] The light irradiation device 50 irradiates light to cure the ink. The light irradiation device 50 cures the photocurable ink (e.g., ultraviolet-curable ink) ejected onto the substrate 5 by irradiating it with light (e.g., ultraviolet light), thereby fixing the photocurable ink to the substrate 5. As shown in Figure 3, the light irradiation device 50 is located to the left of the multiple ink heads 40. The light irradiation device 50 is fixed to the left side of the carriage 60 (see Figure 2). However, the light irradiation device 50 may be located to the right of the multiple ink heads 40, or it may be located both to the left and right of the ink heads 40. The light irradiation device 50 comprises a case 51, one or more light sources 52 housed in the case 51 that generate light to cure the ink, and an irradiation port 53 formed on the lower surface of the case 51. The light irradiation device 50 irradiates light downward from the irradiation port 53.
[0026] The carriage moving device 65 moves the carriage 60 in the main scanning direction Y. As shown in Figure 2, the carriage moving device 65 includes a guide rail 66, left and right pulleys 67L and 67R, an endless belt 68, and a carriage motor 69. The guide rail 66 is provided above the main frame 35, more specifically above the opening 35a. The guide rail 66 is positioned above the table unit 70. The guide rail 66 extends in the main scanning direction Y. The carriage 60 is slidably engaged with the guide rail 66 in the main scanning direction Y.
[0027] As shown in Figure 2, the left pulley 67L is located to the left of the left end of the guide rail 66. The right pulley 67R is located to the right of the right end of the guide rail 66. The left pulley 67L and the right pulley 67R are fixed to the main frame 35. The belt 68 is wrapped around the left pulley 67L and the right pulley 67R. The belt 68 is fixed to the back of the carriage 60. The carriage motor 69 is connected to the right pulley 67R. However, the carriage motor 69 may also be connected to the left pulley 67L. When the carriage motor 69 is driven, the right pulley 67R rotates, and the belt 68 travels between the left pulley 67L and the right pulley 67R. As a result, the carriage 60 moves along the guide rail 66 in the main scanning direction Y. As the carriage 60 moves in the main scanning direction Y, the ink head 40 and the light irradiation device 50 mounted on the carriage 60 also move in the main scanning direction Y.
[0028] [Rotating device] The rotating device 80 is mounted below the carriage 60, in this case on the table 71, and supports and rotates the cylindrical workpiece 5. However, the rotating device 80 may be configured to hold and rotate one or both ends of the workpiece 5. The configuration of the rotating device 80 is not particularly limited as long as it rotates the cylindrical workpiece 5 around its axis. The rotating device 80 is configured to be detachable from the table 71. The rotating device 80 is fixed to the table 71 when printing on the cylindrical workpiece 5, and removed from the table 71 when printing on workpieces 5 that do not require rotation. The rotating device 80 moves with the table 71 in the sub-scanning direction X and the vertical direction Z. However, the rotating device 80 may be attached to or detached at any location other than the table 71 and below the range of motion of the carriage 60. The rotating device 80 may be permanently fixed at any location below the range of motion of the carriage 60.
[0029] Figure 4 is a perspective view of the rotating device 80. As shown in Figure 4, the rotating device 80 comprises a frame member 90, a first rotating member 100, a second rotating member 110, and a drive unit 120.
[0030] As shown in Figure 4, the frame member 90 supports the first rotating member 100 and the second rotating member 110 so that they can rotate in the front-rear direction. The frame member 90 is placed on the table 71 and is fixed to the table 71. The frame member 90 is configured as a roughly rectangular box shape with a part of its top surface open. The frame member 90 has a left wall 91L and a right wall 91R.
[0031] The first rotating member 100, together with the second rotating member 110, supports the workpiece 5 to be printed. The first rotating member 100 comprises a first shaft 101 extending in the main scanning direction Y, and a plurality of first rollers 102 inserted through the first shaft 101. The first shaft 101 is configured to be rotatable about an axis extending in the main scanning direction Y. The left end of the first shaft 101 is rotatably supported by the left wall 91L of the frame member 90. The right end of the first shaft 101 is rotatably supported by the right wall 91R of the frame member 90.
[0032] The first roller 102 is an anti-slip member that prevents the workpiece 5 from sliding relative to the rotating first shaft 101. The first roller 102 is configured to slide and fix relative to the first shaft 101 in the main scanning direction Y. The position of the first roller 102 in the main scanning direction Y is changeable. The first rotating member 100 supports the workpiece 5 with at least some of the first rollers 102 among the plurality of first rollers 102.
[0033] The second rotating member 110 supports the workpiece 5 together with the first rotating member 100. The second rotating member 110 is positioned alongside the first rotating member 100 in the sub-scanning direction X. Here, the second rotating member 110 is positioned in front of the first rotating member 100. The second rotating member 110 comprises a second shaft 111 extending in the main scanning direction Y, and a plurality of second rollers 112 inserted through the second shaft 111. The second shaft 111 is configured to be rotatable about an axis extending in the main scanning direction Y. The left end of the second shaft 111 is rotatably supported by the left wall 91L of the frame member 90. The right end of the second shaft 111 is rotatably supported by the right wall 91R of the frame member 90.
[0034] The second roller 112 is an anti-slip member that prevents the workpiece 5 from sliding relative to the rotating second shaft 111. The second roller 112 is configured to slide and fix relative to the second shaft 111 in the main scanning direction Y. The position of the second roller 112 in the main scanning direction Y is changeable. The second rotating member 110 supports the workpiece 5 with at least some of the second rollers 112 among the plurality of second rollers 112.
[0035] The drive unit 120 is provided on the frame member 90. The drive unit 120 is configured to rotate the first shaft 101 and the second shaft 111. By rotating the first shaft 101 and the second shaft 111, the drive unit 120 rotates the workpiece 5 to be printed. As shown in Figure 4, the drive unit 120 includes a drive motor 121, a gear group 122 consisting of multiple gears and pulleys, and a belt 123 wrapped around the drive motor 121, the gear group 122, the first shaft 101, and the second shaft 111.
[0036] When the drive motor 121 is driven, the belt 123 moves. This causes the first shaft 101 and the second shaft 111, around which the belt 123 is wound, to rotate. In this embodiment, the workpiece 5 supported by the first shaft 101 and the second shaft 111 rotates in the direction of arrow R in Figure 4.
[0037] [Motor Encoder] The printer 10 is equipped with a motor encoder 130 that detects the rotational position of the rotating device 80. The motor encoder 130 is an example of a detection device capable of detecting the rotational position of the rotating device 80. The motor encoder 130 is configured to emit a pulse signal each time the drive motor 121 rotates by a predetermined angle. In this case, the motor encoder 130 is built into the drive motor 121. However, the detection device may be located outside the drive motor 121 and may be configured, for example, to measure the amount of rotation of the rotating shaft of the drive motor 121 or the gears of the gear group 122. When a stepping motor that is driven by receiving pulses is used as the drive motor 121, the device that transmits pulses to control the drive motor 121 may also be the detection device. In this case, the control device 200 detects the rotational position of the rotating device 80 by counting the pulse signals emitted by the motor encoder 130. The rotational position of the rotating device 80 may be a relative rotational position without a specific reference position, or it may be an absolute rotational position with respect to a reference position. The control device 200 controls the drive motor 121, including whether to drive it or stop it and its rotational speed, based on the pulse signals emitted by the motor encoder 130.
[0038] [Sensor] The sensor 140 is configured to detect the mark 6 (see Figure 6) applied to the material to be printed 5. As shown in Figure 2, in this embodiment, the sensor 140 is mounted on the carriage 60. The position of the sensor 140 in the sub-scanning direction X is fixed. As shown in Figure 5, in this embodiment, the sensor 140 is an optical sensor comprising a light-emitting unit 141 that emits light and a light-receiving unit 142 that receives light. Here, the sensor 140 is a reflective optical sensor. The light-receiving unit 142 receives light emitted from the light-emitting unit 141 and reflected by the material to be printed 5. The sensor 140 transmits a signal corresponding to the amount of light that reaches the light-receiving unit 142. The amount of reflected light reaching the light-receiving unit 142 differs depending on whether the mark 6 is located where the light-emitting unit 141 emits light or where the mark 6 is located where the light-emitting unit 141 emits light, and the level of the signal transmitted by the sensor 140 also differs. The control device 200 receives a signal from the sensor 140 and determines whether the sensor 140 has detected mark 6. However, the configuration of the sensor 140 is not limited to that described above. The sensor 140 may be, for example, a camera, and the control device 200 may detect mark 6 by performing image analysis on the image captured by the camera.
[0039] [Control device] Figure 5 is a block diagram of the printer 10. As shown in Figure 5, the control device 200 is connected to a plurality of ink heads 40, a light irradiation device 50, a carriage motor 69 of a carriage moving device 65, a table lifting device 72 of a table unit 70, a drive motor 79 of a table moving device 75, and a drive motor 121 of a rotating device 80, and controls their operation. The control device 200 is also connected to a motor encoder 130 and a sensor 140, and receives signals from them. The configuration of the control device 200 is not particularly limited. The control device 200 is, for example, a microcomputer. The hardware configuration of the microcomputer is not particularly limited, but for example, it includes an interface (I / F) for receiving print data from external devices such as a host computer, a central processing unit (CPU) for executing instructions of the control program, a read-only memory (ROM) for storing programs executed by the CPU, a random access memory (RAM) used as a working area for expanding the program, and a storage device such as memory for storing programs and various data. Some of the functions of the control device 200 may be performed by an external computer or the like, which is located outside the printer 10 and connected to the printer 10.
[0040] As shown in Figure 5, the control device 200 includes a print control unit 210, a circumference measuring unit 220, and an image correction unit 230. The print control unit 210 controls the printing operation of the printer 10. The circumference measuring unit 220 measures and records the circumference of the cylindrical object to be printed 5. The image correction unit 230 corrects the print data to match the recorded circumference of the object to be printed 5. Here, the image correction unit 230 corrects the amount of rotation of the rotating device 80 in one pass (feed amount in one pass) in the print data to match the recorded circumference of the object to be printed 5.
[0041] The printing control unit 210 controls the rotating device 80 to rotate the workpiece 5 and ejects ink from the ink head 40 to print an image based on the image data onto the outer surface of the workpiece 5. More specifically, the printing control unit 210 intermittently rotates the rotating device 80 by the amount of rotation determined by the image correction unit 230 (more specifically, the rotation amount calculation unit 231 described later) and ejects ink from the ink head 40 to form an image. The printing control unit 210 drives the carriage motor 69 to move the carriage 60 in the main scanning direction Y and ejects ink from the ink head 40.
[0042] As shown in Figure 5, the circumference measuring unit 220 includes a mark printing unit 221, a mark detection unit 222, a rotation control unit 223, a start point recording unit 224, an end point recording unit 225, a circumference calculation unit 226, and a circumference recording unit 227.
[0043] The mark printing unit 221 controls at least the ink head 40 to print the mark 6 on the outer surface of the material to be printed 5. When printing the mark 6, the rotating device 80 does not need to be driven if it is not necessary. The mark detection unit 222 controls the sensor 140 to detect the mark 6. Here, the mark detection unit 222 detects that the mark 6 is located at a predetermined position within the field of view of the sensor 140. The mark detection unit 222 detects the boundary position between the position where the sensor 140 detects the mark 6 and the position where it does not, with respect to the rotation direction of the material to be printed 5.
[0044] The rotation control unit 223 controls the rotating device 80 to rotate the print material 5. The rotation of the print material 5 by the rotation control unit 223 is performed prior to printing in order to measure the circumference of the print material 5. The starting point recording unit 224 records the rotation position of the rotating device 80 when the print material 5 is at the starting point of rotation. The rotation position of the rotating device 80 is obtained from the motor encoder 130. In this embodiment, the starting point recording unit 224 records the rotation position of the rotating device 80 when the sensor 140 detects the mark 6 as the starting point of rotation of the print material 5. At this time, the rotation control unit 223 controls the rotating device 80 so that the mark 6 is located at a predetermined position within the field of view of the sensor 140. The position of the starting point of rotation is recorded at least temporarily.
[0045] The endpoint recording unit 225 records the rotational position of the rotating device 80 when the printed material 5 has been rotated and returned to the starting point of rotation. Here, the endpoint recording unit 225 records the rotational position of the rotating device 80 when the sensor 140 detects the mark 6 again.
[0046] The circumference calculation unit 226 determines the circumference of the outer surface of the printed material 5 based on the rotation position of the rotating device 80 recorded in the starting point recording unit 224 (hereinafter also referred to as the starting position) and the rotation position of the rotating device 80 recorded in the ending point recording unit 225 (hereinafter also referred to as the ending position). The circumference of the outer surface of the printed material 5 is the distance corresponding to the difference between the ending position and the starting position. For example, if the difference between the ending position and the starting position is the rotation angle of the drive motor 121, the circumference of the outer surface of the printed material 5 is determined by multiplying the gear ratio of the gear group 122, the circumference of the second roller 112, and the angle difference between the ending position and the starting position (ratio to 1 rotation = 360 degrees).
[0047] The circumference recording unit 227 records the circumference calculated by the circumference calculation unit 226. In this embodiment, since the circumference of each individual printable object 5 is measured, the recording of the circumference of the printable object 5 may be temporary. However, the circumference of the printable object 5 may be registered non-temporarily in the circumference recording unit 227 so that it can be reused when printing on the same printable object 5 (preferably a printable object 5 with little individual variation).
[0048] As shown in Figure 5, the image correction unit 230 includes a rotation amount calculation unit 231. The rotation amount calculation unit 231 calculates the amount of one rotation of the rotating device 80 during printing from the circumference of the material to be printed 5 recorded in the circumference recording unit 227. During printing, ink ejection and rotation of the rotating device 80 are performed alternately while the carriage 60 moves in the main scanning direction Y, and the "amount of one rotation of the rotating device 80" is the amount of one rotation in this intermittent rotational operation of the rotating device 80. The calculation of the amount of one rotation of the rotating device 80 is performed so that no gap or overlap occurs between the start and end points of printing. In this embodiment, the rotation amount calculation unit 231 corrects the amount of one rotation of the rotating device 80, which has been determined in advance from the resolution of the material to be printed 5 in the rotation direction, to an amount of rotation that divides the circumference of the material to be printed 5 evenly. This makes it possible to prevent gaps or overlaps in the image from occurring between the start and end points of printing.
[0049] [Print the mark] The following describes the process of printing Mark 6. Figure 6 is a schematic plan view of the substrate 5 on which Mark 6 has been printed. Figure 7 is a flowchart related to the printing of Mark 6. As shown in Figure 7, in step S01 of the Mark 6 printing process, a printing sheet 7 is attached to the outer surface of the substrate 5. As shown in Figure 6, Mark 6 is printed on the sheet 7. However, Mark 6 may also be printed directly on the substrate 5. In this specification, descriptions such as "applying a mark to the outer surface of the substrate 5 (three-dimensional object)" include both directly printing Mark 6 on the outer surface of the substrate 5 and indirectly printing Mark 6 on the outer surface of the substrate 5 via a sheet 7 or the like. The sheet 7 is preferably a color that makes the boundary with Mark 6 easily detectable by the sensor 140. By using the sheet 7, the position of Mark 6 can be reliably detected regardless of the color of the substrate 5. Also, as will be described later, the sheet 7 is peeled off the substrate 5 after the circumference of the substrate 5 is measured and before the image is printed. Therefore, the Mark 6 does not remain in the printed image.
[0050] As shown in Figure 7, in step S02, the material to be printed 5 with the sheet 7 attached is supported by the rotating device 80. In step S03, the mark 6 is printed on the sheet 7. The position of the mark 6 relative to the circumferential direction of the material to be printed 5 can be any position. As shown in Figure 6, the mark 6 is, for example, a solid rectangular image. However, the shape of the mark 6 is not particularly limited. The mark 6 may be, for example, a thin line extending in the axial direction of the material to be printed 5.
[0051] In this embodiment, the mark 6 is printed using the printer 10 that measures the circumference of the object to be printed 5, but the mark 6 may also be printed using another printer or the like. The mark 6 is not limited to a printed mark. The mark 6 may be, for example, a three-dimensional shape provided on the object to be printed 5 (e.g., a notch or a scribed line). The mark 6 may also be, for example, a sticker or the like affixed to the object to be printed 5.
[0052] [Circumference measurement and rotation amount correction] Next, the process of measuring the circumference of the material to be printed 5 and correcting the rotation amount of the rotating device 80 will be described. Figure 8 is a flowchart relating to the measurement of the circumference of the material to be printed 5 and the correction of the rotation amount of the rotating device 80. As shown in Figure 8, in step S10 of measuring the circumference of the material to be printed 5, the rotating device 80 is made to support the material to be printed 5. If the circumference measurement is performed immediately after printing the mark 6, the work in step S10 has already been performed in step S02.
[0053] In step S20, the starting point for the rotation of the workpiece 5 by the rotating device 80 is determined. Here, the printer 10 drives the rotating device 80 at a low speed while referring to the detection result of the sensor 140, and moves the rotating device 80 to a rotation position where the boundary between the mark 6 and the area outside the mark 6 is detected by the sensor 140. The rotation position of the rotating device 80 after step S20 becomes the starting position for circumference measurement. Here, the starting position for circumference measurement is assumed to be the position where the end 6F (see Figure 6) on the front side of the rotation direction of the mark 6 (direction R in Figure 6) is detected by the sensor 140. However, the reference point for the starting position is not limited to any part of the mark 6. In step S30, the rotation position of the rotating device 80 when the workpiece 5 is at the starting point is recorded based on the detection of the motor encoder 130. Note that this "recording" also includes resetting the rotation position of the rotating device 80 (i.e., recording position "0").
[0054] In step S40, the rotating device 80 is driven to rotate the workpiece 5 from its starting point. In step S50, the rotating device 80 is stopped at the position where the workpiece 5 has rotated back to its starting point. Preferably, the printer 10 may be configured to stop the rotating device 80 when the sensor 140 detects the front end 6F of the mark 6 in the direction of travel, and then rotate the workpiece 5 at a low speed in the opposite direction of R to find the exact position of the front end 6F of the mark 6 in the direction of travel. The rotation position of the rotating device 80 after step S50 becomes the endpoint position for circumference measurement. In step S60, the rotation position of the rotating device 80 at this time (when the workpiece 5 has rotated back to its starting point) is recorded.
[0055] In step S70, the circumference of the outer surface of the printed material 5 is determined based on the rotation position of the rotating device 80 at the starting point (starting position) and the rotation position of the rotating device 80 when it returns to the starting point (ending position).
[0056] In step S80, the perimeter obtained in step S70 is recorded. In step S90, the amount of rotation of the rotating device 80 during printing (the circumferential feed distance of the print material 5 for each printing pass) is calculated from the recorded perimeter of the print material 5.
[0057] [printing] Before printing on the substrate 5, the sheet 7 is peeled off the substrate 5. Then, the substrate 5 is supported by the rotating device 80. The starting position for printing on the substrate 5 in the circumferential direction may be any position desired by the user, and may be any position as long as the substrate 5 is a cylindrical shape with uniform circumference. However, if a mark 6 is directly applied to the substrate 5, the starting position for printing on the substrate 5 in the circumferential direction may be related to the position of the mark 6. For example, the print image may be set to fill in the mark 6. To ensure that the mark 6 does not affect the quality of the print image, the print image may be formed at a position away from the mark 6. In that case, the mark 6 remains on the substrate 5.
[0058] [Effects of the First Embodiment] The following describes the effects and benefits that can be achieved by the printer 10 according to this embodiment.
[0059] The printer 10 according to this embodiment includes a rotating device 80 that supports a cylindrical workpiece 5 and rotates it around its axis, an ink head 40 that is positioned opposite the rotating device 80 and ejects ink onto the outer surface of the workpiece 5 supported by the rotating device 80, a motor encoder 130 that can detect the rotational position of the rotating device 80, and a control device 200. The control device 200 includes a print control unit 210 that controls the rotating device 80 to rotate the workpiece 5, ejects ink from the ink head 40, and prints an image based on image data onto the outer surface of the workpiece 5. The control device 200 further includes a rotation control unit 223 that controls the rotating device 80 to rotate the workpiece 5, a starting point recording unit 224 that records the rotation position of the rotating device 80 when the workpiece 5 is at the starting point of rotation, an ending point recording unit 225 that records the rotation position of the rotating device 80 when the workpiece 5 has been rotated and returned to the starting point of rotation, and a circumference calculation unit 226 that calculates the circumference of the outer surface of the workpiece 5 based on the rotation position recorded in the starting point recording unit 224 and the rotation position recorded in the ending point recording unit 225.
[0060] According to the printer 10 of this embodiment, the circumference of the outer surface of the printable object 5 can be determined based on the rotational position of the rotating device 80 at the starting point of the printable object 5 and the rotational position of the rotating device 80 when the printable object 5 is back at the starting point.
[0061] Traditionally, the diameter of the object to be printed 5 was either known by its nominal value or measured by the user using a caliper, for example. The nominal or measured diameter of the object to be printed 5 was entered into the printer by the user, and the printer calculated the circumference of the object to be printed 5 from the entered diameter. However, the accuracy of measuring the diameter of the object to be printed 5 depends on the user's measurement skills. Also, the actual diameter of the object to be printed 5 may vary from the nominal value. There is also the possibility of the user making a mistake and entering an incorrect diameter. Furthermore, if the cross-section of the object to be printed 5 is not a perfect circle, the circumference cannot be accurately determined by calculation based on the diameter. If the circumference of the object to be printed 5 is inaccurate, the difference between the calculated circumference and the actual circumference will be large, which may result in gaps or overlaps in the image between the start and end points of printing.
[0062] According to the printer 10 of this embodiment, the circumference of the object to be printed 5 can be accurately measured. Therefore, gaps or overlaps in the image between the start and end points of printing can be suppressed. In addition, printing failures due to errors in measuring or inputting the diameter of the object to be printed 5 can be prevented.
[0063] In this embodiment, a mark 6 is applied to the outer surface of the material to be printed 5. The printer 10 is equipped with a sensor 140 capable of detecting the mark 6. The start point recording unit 224 records the rotation position of the rotating device 80 when the sensor 140 detects the mark 6 as the starting point of the rotation of the material to be printed 5. The end point recording unit 225 records the rotation position of the rotating device 80 when the sensor 140 detects the mark 6 again. With this configuration, the start and end points of circumference measurement can be accurately detected using the mark 6.
[0064] In this embodiment, the sensor 140 is an optical sensor comprising a light-emitting unit 141 that emits light and a light-receiving unit 142 that receives light. With this configuration, the mark 6 can be reliably detected by the optical sensor 140. Furthermore, the sensor can be provided at a lower cost compared to using, for example, a camera.
[0065] In this embodiment, the control device 200 includes a mark printing unit 221 that controls at least the ink head 40 to print the mark 6 on the outer surface of the material to be printed 5. With this configuration, the printer 10 can apply the mark 6 to the material to be printed 5. Therefore, there is no need to prepare any other printers or devices for applying the mark 6 to the material to be printed 5.
[0066] In this embodiment, the control device 200 includes a circumference recording unit 227 in which the circumference calculated by the circumference calculation unit 226 is recorded, and a rotation amount calculation unit 231 in which the amount of one rotation of the rotating device 80 during printing is calculated from the circumference recorded in the circumference recording unit 227. The print control unit 210 intermittently rotates the rotating device 80 by the amount of one rotation calculated by the rotation amount calculation unit 231 and ejects ink from the ink head 40 to form an image. With this configuration, the amount of one rotation of the rotating device 80 can be determined in accordance with the measured circumference of the material to be printed 5. As a result, it is possible to prevent gaps or overlaps in the image between the start and end points of printing.
[0067] [For multi-layer printing] According to the printer 10 of this embodiment, it is also possible to perform multilayer printing, in which multiple ink layers are superimposed on the outer surface of the object to be printed 5. As shown in Figure 5, the print control unit 210 includes a return control unit 211 that moves the object to be printed 5 to the print start position after printing is completed. After printing one ink layer is completed, the printer 10 returns the object to be printed 5 to the print start position and starts printing the next ink layer. In the printer 10 of this embodiment, since the circumference of the object to be printed 5 has been determined, the rotation direction of the return operation of the object to be printed 5 for printing the next ink layer can be set to a direction in which the return distance is shorter.
[0068] The return control unit 211 controls the rotation device 80 to rotate the print target 5 in the opposite direction to the printing direction and move it to the printing start position if the length of the image relative to the rotation direction of the print target 5 is less than half of the circumference recorded in the circumference recording unit 227. Furthermore, if the length of the image is longer than half of the circumference recorded in the circumference recording unit 227, the return control unit 211 controls the rotation device 80 to rotate the print target 5 in the same direction as the printing direction and move it to the printing start position. If the length of the image is equal to half of the circumference recorded in the circumference recording unit 227, the print target 5 may be rotated in the rotation direction during printing, or in the opposite direction to the rotation direction during printing. This control reduces the time required to return the print target 5 to the printing start position in multilayer printing.
[0069] [Modified version of the first embodiment] The correction to match the length of the printed image with the circumference of the object to be printed 5 can be performed by means other than correcting the amount of rotation of the rotating device 80 in one cycle. Figure 9 is a block diagram of a modified printer 10. As shown in Figure 9, the image correction unit 230 of the printer 10 in this modified version includes an image length correction unit 232 that corrects the length of the image in the image data with respect to the rotation direction of the object to be printed 5 based on the circumference recorded in the circumference recording unit 227. In this modified version, the length of the printed image and the circumference of the object to be printed 5 are matched by correcting the length of the image in the data. By this method as well, the start and end points of printing can be aligned, and no gaps or overlaps in the image can occur between them.
[0070] [Second Embodiment] In the second embodiment, the printer 10 measures the circumference of the printout 5, with some user intervention. In the following description of the second embodiment, components that perform functions common to the first embodiment will be given the same reference numerals as in the first embodiment. Also, redundant explanations will be omitted or simplified as appropriate. The same applies to other embodiments.
[0071] Figure 10 is a schematic perspective view showing the upper configuration of the rotating device 80. As shown in Figure 10, the printer 10 is equipped with a pointer 150 that irradiates a point-shaped light L1 onto the outer surface of the material to be printed 5. The pointer 150 is provided, for example, on the carriage 60. However, the pointer 150 may be provided on a component of the printer 10 other than the carriage 60. Also, the shape of the light emitted from the pointer 150 is not limited. The pointer 150 may, for example, emit a cross-shaped light L1. In this embodiment, the user confirms that the material to be printed 5 is at the starting point and ending point of rotation from the position pointed to by the light L1 of the pointer 150. Figure 11 is a block diagram of the printer 10 according to the second embodiment.
[0072] As shown in Figure 10, in this embodiment as well, the printed material 5 is marked with a mark 6. In this embodiment, the mark 6 is configured as an annular shape such that the point-shaped light L1 of the pointer 150 fits perfectly inside. However, the shape of the mark 6 is not limited to this, and for example, it may be cross-shaped.
[0073] As shown in Figure 11, the circumference measuring unit 220 according to this embodiment includes a start point input unit 228A and an end point input unit 228B. The rotation control unit 223 is configured to allow the user to rotate the rotating device 80 in the R direction and the opposite direction. When the user operates the start point input unit 228A, the rotation position of the rotating device 80 at that time is recorded as the start point position for circumference measurement. When the user operates the end point input unit 228B, the rotation position of the rotating device 80 at that time is recorded as the end point position for circumference measurement.
[0074] Figure 12 is a flowchart showing an example of measuring the circumference of the printed object 5 according to this embodiment. As shown in Figure 12, in measuring the circumference of the printed object 5 according to this embodiment, in step S11, the printed object 5 is supported by the rotating device 80 (similar to step S10 of the first embodiment). In step S21, the starting point of rotation of the printed object 5 by the rotating device 80 is determined. In this embodiment, in step S21, which determines the starting point of rotation of the printed object 5, a point-shaped light L1 from the pointer 150 is shone on the outer surface of the printed object 5 supported by the rotating device 80, and the rotation position of the printed object 5 when the point-shaped light L1 is shone on the mark 6 is taken as the starting point. Specifically, the user moves the printed object 5 or drives the rotating device 80 to bring the mark 6 into a state where the point-shaped light L1 is shone on it.
[0075] From the state described above, in step S31, when the user operates the start point input unit 228A, the rotation position of the rotating device 80 when the object to be printed 5 is at the start point (when the start point input unit 228A is operated) is recorded in the start point recording unit 224 based on the detection by the motor encoder 130.
[0076] In step S41, the user operates the rotating device 80 to rotate the print target 5. In step S51, the user stops the rotating device 80 at the position where the point-shaped light L1 of the pointer 150 shines on the mark 6 (start point = end point after one rotation). In step S61, the rotation position of the rotating device 80 when the print target 5 has rotated back to the start point is recorded. In step S61, when recording the rotation position of the rotating device 80 when the print target 5 has returned to the start point, the state in which the point-shaped light L1 of the pointer 150 shines on the mark 6 again is defined as the state in which the print target 5 has returned to the start point. Specifically, in step S61, the user operates the end point input unit 228B while the point-shaped light L1 is shining on the mark 6. This records the end point position.
[0077] In step S71, the circumference of the outer surface of the material to be printed 5 is determined based on the rotational position of the rotating device 80 at the starting point and the rotational position of the rotating device 80 when it returns to the starting point. Step S71 is the same as step S70 in the first embodiment. After step S71, steps S80 and S90 may be performed as in the first embodiment.
[0078] Thus, in this embodiment as well, the starting point recording unit 224 records the rotational position of the rotating device 80 when the object to be printed 5 is at the starting point of rotation. However, in this embodiment, the user confirms that the object to be printed 5 is at the starting point of rotation using the light L1 of the pointer 150. The recording of the rotational position of the rotating device 80 is also performed by user operation. Similarly, the ending point recording unit 225 records the rotational position of the rotating device 80 when the object to be printed 5 returns to the starting point of rotation. However, the user confirms that the object to be printed 5 is at the end point of rotation using the light L1 of the pointer 150. Regarding the end point of circumference measurement, the recording of the rotational position of the rotating device 80 is also performed by user operation.
[0079] With this configuration, the sensor 140 can be omitted by making the recording of the start and end points of the circumference measurement a user task. In addition, the processing of the control device 200 that detects the mark 6 with the sensor 140 becomes unnecessary. Therefore, the printer 10 can be simplified and its cost reduced. However, the printer 10 may also be configured to automatically measure the circumference of the printed material 5 by detecting with a sensor whether the light L1 of the pointer 150 is shining on the mark 6.
[0080] [Third Embodiment] In the third embodiment, the printer 10 is configured to determine a more accurate circumference of the printable object 5 based on the circumference of the printable object 5 measured in the same manner as in the first embodiment.
[0081] Figure 13 is a block diagram of the printer 10 according to this embodiment. As shown in Figure 13, the circumference measuring unit 220 according to this embodiment includes a correction pattern printing unit 229A, a correction pattern reading unit 229B, a correction value determination unit 229C, and a correction value recording unit 229D.
[0082] The correction pattern printing unit 229A controls the rotating device 80 and the ink head 40 to print a correction pattern 8 (see Figure 14) on the outer surface of the workpiece 5 to further correct the circumference recorded in the circumference recording unit 227. The correction pattern 8 is printed after the measured circumference is recorded in the circumference recording unit 227. Details of the correction pattern 8 will be described later. The correction pattern reading unit 229B causes the sensor 140A to read the correction pattern 8. In this embodiment, the sensor 140A is a camera (for example, a camera provided on the carriage 60), and the correction value determination unit 229C determines the correction value of the circumference from the image of the correction pattern 8 captured by the sensor 140A. Note that the sensor 140 in the first embodiment may be used to read the correction pattern 8. That is, the mark 6 and the correction pattern 8 may be read with a single sensor. The correction value recording unit 229D records the correction value determined from the correction pattern 8. In this embodiment, the image correction unit 230 uses the corrected perimeter obtained by adding this correction value to the perimeter calculated by the perimeter calculation unit 226.
[0083] Figure 14 is a schematic plan view of the printed material 5 on which the correction pattern 8 is printed. As shown in Figure 14, the correction pattern 8 includes a plurality of judgment patterns 8A to 8E. The plurality of judgment patterns 8A to 8E are arranged in a line along the axial direction of the printed material 5. Each of the plurality of judgment patterns 8A to 8E includes a first pattern 8A1 to 8E1 printed at one position in the rotational direction of the printed material 5, and a second pattern 8A2 to 8E2 corresponding to the first pattern 8A1 to 8E1. Each of the second patterns 8A2 to 8E2 is located in the rotational direction of the printed material 5 by a length obtained by adding a predetermined length (hereinafter, this predetermined length will also be called the correction value) to the circumference recorded in the circumference recording unit 227, from the corresponding first pattern 8A1 to 8E1. The correction value is different for each judgment pattern 8A to 8E.
[0084] The correction values for judgment patterns 8A to 8E differ in units of correction for the perimeter of the printed material 5, for example, in increments of 0.05 mm. The correction values include "0", positive values, and negative values. When the perimeter recorded in the perimeter recording unit 227 is approximately equal to the perimeter of the printed material 5, the first and second patterns in the correction pattern with a correction value of "0" will approximately match. For example, when the perimeter recorded in the perimeter recording unit 227 is approximately 0.05 mm longer than the perimeter of the printed material 5, the first and second patterns in the correction pattern with a correction value of "-0.05 mm" will approximately match. For example, when the perimeter recorded in the perimeter recording unit 227 is approximately 0.05 mm shorter than the perimeter of the printed material 5, the first and second patterns in the correction pattern with a correction value of "+0.05 mm" will approximately match.
[0085] As shown in Figure 14, in this embodiment, the first patterns 8A1 to 8E1 each have the shape of a parallelogram including a hypotenuse extending in the rotational direction of the printed material 5. The shapes of the first patterns 8A1 to 8E1 are the same. The second patterns 8A2 to 8E2 have the same shape as the first patterns 8A1 to 8E1. As shown in Figure 14, in the judgment pattern to which a correction value corresponding to the actual perimeter of the printed material 5 is applied (judgment pattern 8B in the example shown in Figure 14), the first pattern 8B1 and the second pattern 8B2 overlap almost completely. In other judgment patterns to which a correction value not corresponding to the actual perimeter of the printed material 5 is applied, the first pattern and the second pattern will not overlap.
[0086] In this embodiment, for each judgment pattern 8A to 8E, the amount of deviation between the first pattern and the second pattern is detected by the sensor 140A. The correction value determination unit 229C selects the judgment pattern with the smallest amount of deviation between the first pattern and the second pattern (in the example of Figure 14, judgment pattern 8B) from the image of the correction pattern 8 captured by the sensor 140A. The correction value determination unit 229C determines the correction value of the judgment pattern 8B with the smallest amount of deviation between the first pattern 8B1 and the second pattern 8B2 (here, +0.05 mm) as the correction value for the circumference of the printed material 5.
[0087] Figure 15 is a flowchart showing an example of perimeter correction of the material to be printed 5. As shown in Figure 15, step S100 of perimeter correction of the material to be printed 5 is performed after step S80 in Figure 8. In step S100, the first patterns 8A1 to 8E1 are printed on the material to be printed 5 (sheet 7). In step S110, the rotating device 80 is driven to rotate the material to be printed 5 by the perimeter determined in step S70. In step S120, the second patterns 8A2 to 8E2 are printed on the material to be printed 5 (sheet 7). At this time, the correction pattern printing unit 229A prints the second patterns 8A2 to 8E2 by shifting the position in the R direction by correction units (0.05 mm in this example). In step S130, the correction pattern 8 is imaged by the sensor 140A. In step S140, the judgment pattern with the smallest difference between the first and second patterns (judgment pattern 8B in the example in Figure 14) is selected from the image acquired by sensor 140A. In step S150, the selected correction value (+0.05 mm in the example in Figure 14) is recorded.
[0088] With this configuration, the circumference of the printed material 5 can be determined more accurately by further correcting the measured circumference of the printed material 5 using the correction pattern 8.
[0089] The shape of the correction pattern 8 is not limited to the shape described above. The correction pattern 8 may have a shape such as that shown in Figure 16. As shown in Figure 16, the correction pattern 8 in other embodiments may include a rectangular first pattern 8A1 to 8E1 and a rectangular second pattern 8A2 to 8E2 of a different size from the first pattern 8A1 to 8E1. For example, in a determination pattern where the length obtained by adding the correction value to the perimeter recorded in the perimeter recording unit 227 (the length decreases if the correction value is negative) is shorter than the perimeter of the printed material 5 (the correction value is insufficient), a gap will be created between the first pattern and the second pattern. In a determination pattern where the length obtained by adding the correction value to the perimeter recorded in the perimeter recording unit 227 is longer than the perimeter of the printed material 5 (the correction value is excessive), an overlap will occur between the first pattern and the second pattern. In this case, the correction value determination unit 229C determines the correction value of the determination pattern with the smallest overlap or gap between the first pattern and the second pattern as the correction value for the perimeter of the printed material 5.
[0090] The correction pattern 8 may consist of only one set of first and second patterns (for example, first pattern 8A1 and second pattern 8A2). Even in this case, the correction value for the perimeter of the printed material 5 can be determined by measuring the amount of displacement between the first pattern 8A1 and the second pattern 8A2 (the width of the gap between them, or the overlap width).
[0091] As a variation of this embodiment, the user may visually inspect the correction pattern 8 and select the most appropriate correction value. In this case, the selected correction value may be input to the printer 10 by the user. Furthermore, the perimeter correction using the correction pattern 8 may be combined with embodiments other than the first embodiment, for example, the second embodiment.
[0092] [Other embodiments] Several preferred embodiments of the present invention have been described above. However, the embodiments described above are merely illustrative, and the technology disclosed herein can be implemented in various other forms. For example, in the embodiments described above, the starting point of rotation of the printed material 5 was determined using the mark 6. However, the starting point of rotation of the printed material 5 may be determined based on something other than the marked mark 6. For example, the starting point of rotation of the printed material 5 may be determined based on partial features of the printed material 5 itself (e.g., the edges of any missing parts).
[0093] The configuration of printer 10 described above is merely illustrative, and the printer configuration is not limited thereto. For example, the printer may be one in which the rotating mechanism is not detachable. For example, the printer may not be a UV printer that forms images with ultraviolet-curing ink, but rather a printer that forms images with thermosetting ink, for example.
[0094] The rotating device 80 described above was configured to rotate the workpiece 5 around an axis extending in the main scanning direction Y on which the carriage 60 moves, but the direction of rotation of the workpiece 5 is not limited to this. The rotating device 80 may also rotate the workpiece 5 around an axis extending in the sub-scanning direction X (the direction in which the nozzles are aligned in each ink head 40). In this case, with the carriage 60 stopped above the workpiece 5, ink may be ejected from the ink head 40 toward the workpiece 5 which is being rotated by the rotating device 80.
[0095] Unless otherwise specified, the embodiments do not limit the present invention. [Explanation of Symbols]
[0096] 5 Printing material (three-dimensional object) 6 marks 7 sheets 8 Correction Patterns 8A~8E Judgment Patterns 8A1~8E1 Pattern 1 8A2~8E2 Second Pattern 10 Printers 40 Inkheads 80 Rotation device 130 Motor Encoder (Detection Device) 140 sensors 141 Lighting Unit 142 Light receiving part 150 pointers 200 Control device 210 Printing Control Unit 211 Return Control Unit 220 Perimeter measurement section 221 Mark Printing Department 222 Mark detection unit 223 Rotation Control Unit 224 Starting Point Recording Section (First Recording Section) 225 Final Point Recording Section (Second Recording Section) 226 Perimeter calculation section (1st calculation section) 227 Circumference Record Department (3rd Record Department) 228A Starting point input section 228B End point input section 229A Correction pattern printing section 229B Correction pattern reading unit 229C Correction Value Determination Unit 229D Correction Value Recording Unit (4th Recording Unit) 230 Image Correction Unit 231 Rotation Amount Calculation Unit (Second Calculation Unit) 232 Image length correction unit (correction unit)
Claims
1. A rotating device that supports a cylindrical three-dimensional object and rotates it around its axis, An ink head is provided opposite the rotating device and ejects ink onto the outer surface of the three-dimensional object supported by the rotating device, A detection device capable of detecting the rotational position of the aforementioned rotating device, A control device is provided, The control device includes a printing control unit that controls the rotating device to rotate the three-dimensional object, ejects the ink from the ink head, and prints an image based on image data onto the outer surface of the three-dimensional object. The control device further, A rotation control unit that controls the rotation device to rotate the three-dimensional object, A first recording unit records the rotational position of the rotating device when the three-dimensional object is at the starting point of rotation, A second recording unit records the rotational position of the rotating device when the three-dimensional object is rotated and returns to the starting point of the rotation, The system includes a first calculation unit that determines the circumference of the outer surface of the three-dimensional object based on the rotational position recorded in the first recording unit and the rotational position recorded in the second recording unit. Printer.
2. The outer surface of the three-dimensional object is marked, The system further includes a sensor capable of detecting the aforementioned mark, The first recording unit records the rotational position of the rotating device when the sensor detects the mark as the starting point of the rotation of the three-dimensional object. The second recording unit records the rotational position of the rotating device when the sensor detects the mark again. The printer according to claim 1.
3. The aforementioned sensor is an optical sensor comprising a light-emitting unit that emits light and a light-receiving unit that receives light. The printer according to claim 2.
4. The control device includes at least a mark printing unit that controls the ink head to print the mark on the outer surface of the three-dimensional object. The printer according to claim 2.
5. The control device is A third recording unit records the circumference obtained by the first calculation unit, The system comprises a second calculation unit that calculates the amount of rotation of the rotating device during printing from the circumference recorded in the third recording unit, The print control unit intermittently rotates the rotating device by the amount of rotation determined by the second calculation unit and ejects the ink from the ink head to form an image. The printer according to claim 1.
6. The control device is A third recording unit records the circumference obtained by the first calculation unit, The system includes a correction unit that corrects the length of the image of the three-dimensional object in the image data with respect to the rotation direction, based on the circumference recorded in the third recording unit. The printer according to claim 1.
7. The control device includes a third recording unit in which the circumference determined by the first calculation unit is recorded. The printing control unit includes a return control unit that moves the three-dimensional object to the printing start position after printing is completed. The return control unit controls the rotation device to rotate the object in the opposite direction to the printing direction and move it to the printing start position if the length of the image relating to the rotation direction of the object is less than half of the circumference recorded in the third recording unit, and controls the rotation device to rotate the object in the same direction as the printing direction and move it to the printing start position if the length of the image is longer than half of the circumference recorded in the third recording unit. The printer according to claim 1.
8. The control device is A third recording unit records the circumference obtained by the first calculation unit, A correction pattern printing unit controls the rotating device and the ink head to print a correction pattern on the outer surface of the three-dimensional object to further correct the circumference recorded in the third recording unit, The system includes a fourth recording unit that records the correction value determined from the correction pattern, The printer according to claim 1.
9. A method for determining the circumference of the outer surface of a three-dimensional object using a printer for printing three-dimensional objects, the printer comprising: a rotating device that supports a cylindrical three-dimensional object and rotates it around an axis; an ink head that ejects ink onto the outer surface of the three-dimensional object supported by the rotating device; and a detection device capable of detecting the rotational position of the rotating device, The step of supporting the three-dimensional object with the rotating device, A step of determining the starting point of the rotation of the three-dimensional object by the rotating device, A step of recording the rotational position of the rotating device when the three-dimensional object is at the starting point, based on the detection of the detection device, A step of driving the rotating device to rotate the three-dimensional object from the starting point, A step of recording the rotational position of the rotating device when the three-dimensional object has rotated and returned to the starting point, The process includes determining the circumference of the outer surface of the three-dimensional object based on the rotational position at the starting point and the rotational position when returning to the starting point. Method for measuring the circumference of a three-dimensional object.
10. The process further includes the step of applying a mark to the outer surface of the three-dimensional object, In the step of determining the starting point of rotation of the three-dimensional object, light is shone onto the outer surface of the three-dimensional object supported by the rotating device, and the rotational position of the three-dimensional object when the mark is shone with light is defined as the starting point. In the step of recording the rotational position of the rotating device when the three-dimensional object returns to the starting point, the state in which the light is shone on the mark again is defined as the state in which the three-dimensional object has returned to the starting point. A method for measuring the circumference of a three-dimensional object according to claim 9.