JP7148189B1 - printer - Google Patents

Abstract

An object of the present invention is to improve the productivity of printing processing while suppressing deterioration in printing accuracy on a printing object having a three-dimensional shape and suppressing equipment investment. A head for forming an image by ejecting ink droplets facing a printing target surface of a printing substrate fixed on a stage, and a first axis and a second axis perpendicular to the printing target surface. a carriage that is held facing from a third axis direction intersecting the axis and is movable with respect to the stage; and at least two of the first, second and third axes by rotating the carriage about the third axis. and control means for simultaneously moving in each direction above the axis to control ejection of ink droplets. [Selection drawing] Fig. 7

Description

The present invention relates to printing devices.

A print target surface having a three-dimensional shape is arranged to face the XY plane, a print head is opposed to the print target surface from the Z-axis direction, the print head is arranged on a carriage, and the carriage is arranged on the X axis and the Y axis. In a three-dimensional surface printing apparatus having means for freely scanning in each of the axial and Z-axis directions to realize printing on a surface to be printed, the shape of the surface to be printed corresponds to each XY coordinate as height information in the Z-axis direction. and a total amount of movement of the carriage in the Z-axis direction in a scanning format in which main scanning is performed in the X-axis direction and sub-scanning is performed in the Y-axis direction based on the information stored in the storage means. a first calculating means for calculating, a second calculating means for calculating in advance the total amount of movement of the carriage in the Z-axis direction in a scanning format in which main scanning is performed in the Y-axis direction and sub-scanning is performed in the X-axis direction; A three-dimensional surface printing apparatus is known which includes a calculation means and a print control means for printing by adopting the scan format with the smaller total movement amount calculated in advance by the second calculation means (Patent Document 1).

A multi-axis robot, a push-type inkjet head, an ink tank, and a pressure control unit are provided, the push-type inkjet head is connected to the multi-axis robot, and the multi-axis robot is connected to the push-type inkjet head. It has a function to independently control the height, position in the horizontal plane, and tilt. The ink tank supplies ink to the push-type inkjet head, and the pressure control unit controls the ink tank according to the operating state of the multi-axis robot. There is also known an inkjet device having a function of controlling the pressure applied to the (Patent Document 2).

Japanese Patent Application Laid-Open No. 2001-10032 JP 2016-131914 A

INDUSTRIAL APPLICABILITY The present invention improves the productivity of printing processing while suppressing deterioration in printing accuracy on a printing object having a three-dimensional shape and suppressing equipment investment.

In order to solve the above problems, the printing apparatus according to claim 1 comprises:
a head that forms an image by ejecting ink droplets facing a printing target surface of a printing material having a three-dimensional shape fixed on a mounting surface of a stage;
The head is held facing the surface to be printed from a first axis perpendicular to the mounting surface of the stage and perpendicular to each other, and a third axis perpendicular to the second axis. a carriage movable in each direction of the first axis and the second axis;
While adjusting the head gap, which is the distance to the surface to be printed directly under the nozzle rows of the head, the maximum value of the head gap over the entire print area of the surface to be printed is within a predetermined distance. a control means for rotating the carriage around the third axis to simultaneously move the carriage in each direction of the first axis and the second axis to control ejection of the ink droplets;
It is characterized by

The invention according to claim 1 to 3 is the printing apparatus according to any one of claims 1 to 12,
The head has nozzles for ejecting the ink droplets extending in a direction intersecting the moving direction of the carriage to form a nozzle row. A plurality of types of heads including a color head are arranged side by side in the movement direction of the carriage,
It is characterized by

The invention according to claims 1 to 4 is the printing apparatus according to claims 1 to 3 ,
The plurality of types of heads include a primer head that ejects adhesive ink droplets, a white head that ejects white ink droplets that form a base layer, a special color head that ejects special color ink, and ink droplets that protect the surface of the image. including at least one of the ejecting topcoat heads;
It is characterized by

The invention according to Claims 1 to 5 is the printing apparatus according to Claims 1 to 4 ,
At least one of the spot color heads is arranged side by side in a direction intersecting with the moving direction of the carriage,
It is characterized by

The invention according to claims 1 to 6 is the printing apparatus according to any one or 3 of claims 1 to 3 to 15,
The carriage is provided with a UV lamp row that irradiates ultraviolet rays to cure the ink droplets, or an IR lamp row that irradiates infrared rays to dry the ink droplets.
It is characterized by

The invention according to claims 1 to 7 is the printing apparatus according to claims 1 to 6 ,
The process color head, the spot color head, the primer head, the white head, the top coat head and the UV lamp row, or the IR lamp row are individually arranged in the third axial direction with respect to the printing target surface. movably arranged
It is characterized by

In order to solve the above problems, the printing apparatus according to claim 2 includes :
a head that forms an image by ejecting ink droplets facing a printing target surface of a printing material having a three-dimensional shape fixed on a mounting surface of a stage;
The head is held facing the surface to be printed from a first axis perpendicular to the mounting surface of the stage and perpendicular to each other, and a third axis perpendicular to the second axis. a carriage movable in each direction of the first axis and the second axis;
While adjusting the head gap, which is the distance to the surface to be printed directly under the nozzle rows of the head, the carriage is moved to the third position so that the average value of the head gaps over the entire print area of the surface to be printed is minimized. a control means for rotating about an axis and simultaneously moving in each direction of the first axis and the second axis to control ejection of the ink droplets ;
It is characterized by

In order to solve the above problems, the printing apparatus according to claim 3 is provided with:
a head that forms an image by ejecting ink droplets facing a printing target surface of a printing material having a three-dimensional shape fixed on a mounting surface of a stage;
The head is held facing the surface to be printed from a first axis perpendicular to the mounting surface of the stage and perpendicular to each other, and a third axis perpendicular to the second axis. a carriage movable in each direction of the first axis and the second axis;
While adjusting the head gap, which is the distance to the surface to be printed directly under the nozzle rows of the head, the carriage is moved to the third position so that the average value of the head gap on a specific surface of the surface to be printed is minimized. a control means for rotating about an axis and simultaneously moving in each direction of the first axis and the second axis to control ejection of the ink droplets ;
It is characterized by

The invention according to claim 4 is the printing apparatus according to any one of claims 1 to 3 ,
A first print mode in which the head gap is smaller than usual and a second print mode in which the carriage movement time is the shortest can be selected, and the control means controls the print mode based on the selected print mode. set the rotation angle of the carriage,
It is characterized by

The invention according to claim 5 is the printing apparatus according to any one of claims 1 to 4 ,
further comprising swing means for tilting the head so as to face the surface to be printed,
It is characterized by

The invention according to claim 6 is the printing apparatus according to claim 5 ,
the surface to be printed is inclined with respect to a reference plane formed by the first axis and the second axis;
It is characterized by

The invention according to claim 7 is the printing apparatus according to claim 5 or 6 ,
The oscillating means tilts the head in the moving direction of the carriage to adjust the average value of the head gap over the entire print area of the print target surface to be the smallest.
It is characterized by

The invention according to claim 8 is the printing apparatus according to claim 5 or 6 ,
The oscillating means tilts the head in the moving direction of the carriage and adjusts the average value of the head gap on a specific surface of the surface to be printed to be the smallest.
It is characterized by

The invention according to claim 9 is the printing apparatus according to claim 5 or 6 ,
The oscillating means tilts the head in the moving direction of the carriage and adjusts the maximum value of the head gap over the entire print area of the print target surface to be within a predetermined distance.
It is characterized by

The invention according to claim 10 is the printing apparatus according to claim 5 or 6 ,
The oscillating means tilts the head in a direction intersecting the movement direction of the carriage to adjust the average value of the head gap over the entire print area of the print target surface to be the smallest.
It is characterized by

The invention according to claim 11 is the printing apparatus according to claim 5 or 6 ,
The oscillating means tilts the head in a direction intersecting the movement direction of the carriage to adjust the average value of the head gap on a specific surface of the printing target surface to be the smallest.
It is characterized by

The invention according to claim 1 or 2 is the printing apparatus according to claim 5 or 6 ,
The oscillating means tilts the head in a direction intersecting the moving direction of the carriage, and adjusts the maximum value of the head gap over the entire print area of the print target surface to be within a predetermined distance.
It is characterized by

The invention according to claim 18 is the printing apparatus according to any one of claims 1 to 17 ,
The carriage has mist suction means for sucking gas containing mist of the ink droplets.
It is characterized by

The invention according to claim 19 is the printing apparatus according to any one of claims 1 to 18 ,
The carriage has degassing means for removing oxygen in the ink that forms the ink droplets.
It is characterized by

The invention according to claim 20 is the printing apparatus according to any one of claims 1 to 19 ,
The carriage has a nitrogen replacement mechanism that removes oxygen by introducing nitrogen gas into an atmosphere from when the ink droplets are ejected until they land on the surface to be printed and are cured.
It is characterized by

According to the first aspect of the invention, by rotating the carriage, it is possible to improve the productivity of the printing process on the printing target surface of the printing material having a three-dimensional shape, and to adjust the image quality according to the three-dimensional shape of the printing material. can be suppressed .

According to the 13th aspect of the invention , the productivity of full-color printing can be improved.

According to the 14th aspect of the present invention, a full - color image including special colors can be formed and post-processing can be completed by one movement scanning.

According to the 15th aspect of the invention, a plurality of types of print heads can be arranged in the carriage.

According to the 16th and 17th aspects of the invention, it is possible to complete printing by one movement scanning and improve productivity.

According to the second aspect of the invention, by rotating the carriage, it is possible to improve the productivity of the printing process on the printing target surface of the printing object having a three-dimensional shape, while suppressing the deterioration of the image quality.

According to the third aspect of the present invention, by rotating the carriage, the productivity of the printing process on the printing target surface of the printing object having a three-dimensional shape is improved, and the image quality of the specific printing target surface is improved. Decrease can be suppressed.

According to the fourth aspect of the invention, it is possible to select a print mode of either image quality priority or productivity priority.

According to the fifth aspect of the invention, it is possible to suppress deterioration in printing accuracy for a surface to be printed that is inclined with respect to the reference plane.

According to the sixth aspect of the invention, printing can be performed on a surface to be printed that is inclined with respect to the reference plane.

According to the inventions of Claims 7 , 8 , 9 , 10, 11, and 12, the productivity of the printing process is improved while suppressing the deterioration of the printing precision for the surface to be printed which is inclined with respect to the reference plane. be able to.

According to the eighteenth aspect of the invention, it is possible to absorb the mist generated when the head gap is increased.

According to the 19th and 20th aspects of the invention, it is possible to remove oxygen that inhibits curing of ink droplets.

2 is a block diagram showing an example of the hardware configuration of the printing apparatus according to the first embodiment; FIG. 2 is a block diagram showing the configuration of a printing mechanism; FIG. FIG. 5 is a schematic cross-sectional view for explaining movement of the print head in the carriage in the third axis direction; FIG. 3A is a diagram schematically showing the nozzle arrangement of the print head, and FIG. 3B is a schematic plan view showing the layout of the print head in the carriage; FIG. 11 is a schematic plan view showing the arrangement of print heads according to a modification in a carriage; FIG. 4 is a schematic diagram illustrating movement and scanning of a carriage with respect to a printing target surface of a printing material; 4 is a flow chart showing the control flow of carriage movement scanning in the first embodiment. FIG. 10 is a schematic diagram illustrating a head gap in a region where height data in the direction of the third axis of the printing material changes significantly; 7 is a flow chart showing a control flow of movement scanning for shortening the movement time of the carriage in the first embodiment; 7 is a flow chart showing the flow of control of carriage movement scanning for selecting a print mode in the first embodiment; FIG. 11 is a block diagram showing an example of the hardware configuration of a printing apparatus according to the second embodiment; FIG. FIG. 4 is a schematic diagram showing printing on a printing target surface that is tilted with respect to a reference plane; 10 is a flow chart showing the control flow of carriage movement scanning in the second embodiment.

Next, specific examples of embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the following embodiments.
It should be noted that in the following description using the drawings, the drawings are schematic, and the ratio of each dimension is different from the actual one. Illustrations other than members are omitted as appropriate.

"First Embodiment"
(1) Overall Configuration of Printing Apparatus FIG. 1 is a block diagram showing an example of the hardware configuration of the printing apparatus 1 according to this embodiment, FIG. 2 is a block diagram showing the apparatus configuration of the printing mechanism 40, and FIG. FIG. 5 is a schematic cross-sectional view for explaining movement of the print head PH in the third axis direction;
The configuration of the image forming system according to the present embodiment will be described below with reference to the drawings.

(1-1) Printing Apparatus The printing apparatus 1 includes a control unit 10 that controls the entire apparatus, a communication unit 20 that is used for communication with external devices, and displays an operation screen, etc., and accepts user operations. It has an operation display unit 30, a printing mechanism 40 for forming an image on the printing material S by an inkjet method, and a storage unit 50 for storing image information received from an external device as image data. The control unit 10 and each unit described above are connected through a bus 60 .
In this embodiment, as the printing target S, a three-dimensional object having a three-dimensional shape, for example, a curved surface of a vehicle can be used as a print target surface regardless of the material.

The control unit 10 includes a CPU (Central Processing Unit) that provides various management functions through program execution, a ROM (Read Only Memory) as a storage area for storing BIOS (Basic Input Output System) and the like, and a program execution It has a processor consisting of a RAM (Random Access Memory) used as an area. The program includes firmware and an operating system (OS). One or a plurality of CPUs, ROMs, and RAMs may be provided.

The communication unit 20 is configured by, for example, a LAN (Local Area Network) interface or an IOT (Internet of Things) interface, and communicates with other devices existing on the network. For communication here, for example, an Ethernet (registered trademark) interface, Wifi (registered trademark), Bluetooth (registered trademark), ZigBee (registered trademark), or the like is used.
The operation display unit 30 corresponds to a so-called user interface, and is specifically configured by combining a liquid crystal display panel, an organic EL (Electro Luminescence) display panel, various operation buttons, a touch panel, etc., and is used for various settings and instructions. Used for input and information display.

As shown in FIG. 2, the printing mechanism 40 has a stage 41 (see FIG. 6) on which the material to be printed S is placed and fixed while maintaining a horizontal attitude. A carriage moving mechanism 43 is provided to move the carriage in the first axis (width) and second axis (depth) directions. The carriage movement mechanism 43 is composed of a servomotor SM, a ball screw BS (not shown) and a linear guide LG (not shown).
On the carriage 42, a plurality of types of printing including a process color print head 410 that ejects four types of ink of process colors CMYK (C: cyan, M: magenta, Y: yellow, K: black) as droplets, which will be described later. A head PH (simply referred to as a print head PH when the inks of each color are not distinguished) is arranged. An ink tank 420 (not shown) for supplying ink of each color is connected to each print head PH.

As shown in FIG. 3, each print head PH is held by a print head moving mechanism 44 so as to be individually movable in a third axis direction intersecting (perpendicular to) the first axis and the second axis. The distance between the tip of each ejection nozzle of PH and the printing target surface of the printing material S having a three-dimensional curved surface is always kept at an appropriate distance (printing gap) that matches the characteristics of each print head PH. The print head moving mechanism 44 is also composed of a servomotor SM, a ball screw BS (not shown) and a linear guide LG (not shown).
Furthermore, the carriage 42 is rotatably supported around the third axis by a carriage rotation mechanism 45 that combines a servomotor SM and a harmonic reduction gear HG (not shown).

The control unit 10 is operably connected to the printing mechanism 40, and controls the relative movement between the printing target surface of the printing material S and each print head PH by linear movement three axes and carriage rotation by the carriage movement mechanism 43 and the print head movement mechanism 44. The mechanism 45 rotates on one axis with four degrees of freedom, and controls the amount of ink ejected from each ejection nozzle NZ of each print head PH, ejection timing, and the like.

The storage unit 50 is configured by a storage device such as a hard disk device or a semiconductor memory. In addition to the image data received from the external device, the three-dimensional shape data of the printing material S is also recorded in the storage unit 50 in this embodiment.

(1-2) Carriage FIG. 4A is a diagram schematically showing the nozzle arrangement of the print head PH, and FIG.
The print head PH has, as schematically shown in FIG. 4A, a nozzle row 411 and a nozzle row 412 in which a plurality of nozzles NZ for ejecting ink droplets are aligned at a predetermined pitch p. In this embodiment, a case in which there are two nozzle rows will be described as an example, but the print head PH may have three or more nozzle rows.
The nozzle rows 411 and 412 are arranged in the front-to-rear direction in the traveling direction of the print head PH (indicated by arrows in FIG. 4).

As shown in FIG. 4B, the print head PH having such nozzle rows 411 and 412 is arranged such that the process color print head 410 moves in the moving direction of the carriage 42 (indicated by the arrow in FIG. 4B). C (cyan) print head 410C at the top, M (magenta) print head 410M, Y (yellow) print head 410Y, and K (black) print head 410K are arranged in this order. . In addition, in a direction intersecting the movement direction of the carriage 42 with respect to the process color print head 410, there are a primer print head 410P for ejecting adhesive ink droplets, and a white print head 410W for ejecting white ink droplets for forming a base layer. , top coat print heads 410T for ejecting ink droplets for protecting the surface of an image are arranged to constitute a head row.

A UV lamp row 430 that irradiates ultraviolet rays to cure ink droplets is arranged on the rear end side of the print head PH of each color in the moving direction of the carriage 42 . In this embodiment, each color ink is a pigment-based ink. Each color ink is a solvent UV ink obtained by diluting a UV curable resin (ultraviolet curable resin) that is cured by being irradiated with ultraviolet rays with an organic solvent.
When water-based ink is used as each color ink, instead of the UV lamp row 430, an IR lamp row 440 (not shown) that irradiates infrared rays to dry ink droplets is arranged.

By arranging the primer print head 410P, the top coat print head 410T, the UV lamp row 430 or the IR lamp row 440 in addition to the process color print head 410 in the carriage 42 in this manner, the printing process is completed in one scan. and improve productivity.

"Variation"
FIG. 5 is a schematic plan view showing the arrangement of print heads PH according to a modification in the carriage 42. As shown in FIG.
As shown in FIG. 5, the process color print head 410 includes a C (cyan) print head 410C, an M (magenta) print head 410M, a Y (yellow) print head 410Y, and a K (black) print head. In addition to the print head 410K, a special color print head 410S is arranged side by side in the movement direction of the carriage 42 (indicated by the arrow in FIG. 5).

In addition, in a direction intersecting the movement direction of the carriage 42 with respect to the process color print head 410, there are a primer print head 410P for ejecting adhesive ink droplets, and a white print head 410W for ejecting white ink droplets for forming a base layer. In addition to the top coat print head 410T that ejects ink droplets to protect the surface of the image, other special color print heads 410S1 and 410S2 are arranged to form a head row. Other special color print heads 410S1 include, for example, a gold print head PH, and 410S2 include a silver print head PH.

Thus, in carriage 42, process color printheads 410C, 410M, 410Y, 410K, spot color printheads 410S, 410S1410S2, primer printhead 410P, white printhead 410W, topcoat printhead 410T and UV lamp bank 430, or By arranging the IR lamp row 440, it is possible to complete the printing process in one scan and improve productivity.

The carriage 42 is preferably provided with an oxygen degassing device 450 (not shown) for degassing oxygen contained in the ink in the ink tank 420 . The oxygen degassing device 450 depressurizes the space of the ink tank 420 through a gas-permeable film to degas the space, thereby preventing cavitation and suppressing ejection failures of ink droplets.
Further, it is preferable to provide a nitrogen replacement device 460 (not shown) for replacing oxygen, which inhibits the polymerization reaction of the UV curable resin, with an inert gas such as nitrogen.
Furthermore, it is preferable to provide a mist suction device 470 (not shown) for sucking a small amount of ink mist generated when printing on a three-dimensional object.

(2) Movement and Scanning of Carriage FIG. 6 is a schematic diagram illustrating movement and scanning of the carriage 42 with respect to the surface of the printing material S to be printed.
The carriage 42 is supported by a frame F straddling the printing material S fixed on the mounting surface of the stage 41 in the first axial direction, and is movable on the frame F in the first axial direction by a carriage movement mechanism 43 . there is The frame F is movable in the second axial direction with respect to the stage 41 while straddling the printing material S in the first axial direction. Therefore, the carriage 42 moves on the frame F in the first axis direction while the frame F moves in the second axis direction, as indicated by the arrow in FIG. Printing is performed by ejecting ink droplets from each print head PH arranged in the carriage 42 on the whole.

Furthermore, in this embodiment, the carriage 42 is supported on the frame F so as to be rotatable around the third axis. As a result, as shown in FIG. 6B, the carriage 42 can move and scan the printing target surface of the printing material S in an oblique direction R that intersects the first axis and the second axis in plan view. . As a result, depending on the planar shape and three-dimensional shape of the material to be printed S, the moving scanning direction in which the amount of movement of the carriage 42 in the directions of the first and second axes and the amount of movement of the print head PH in the direction of the third axis are reduced is selected. By calculating and moving and scanning, it is possible to shorten the time required to print an image on the printing material S having a three-dimensional shape and improve the productivity of the printing process.

(2.1) Head Gap Control FIG. 7 is a flow chart showing the control flow of movement scanning of the carriage 42 in this embodiment, and FIG. 4 is a schematic diagram for explaining a head gap G; FIG.
In this embodiment, the carriage 42 is rotated around the third axis that intersects the first and second axes, and the head gap, which is the distance to the surface to be printed directly below the nozzle rows 411 and 412 of the print head PH, is calculated. Adjust G. Specifically, the carriage 42 is rotated so that the average value of the head gap G over the entire print area of the print target surface is minimized. This makes it possible to suppress deterioration in image quality while suppressing deterioration in productivity.

When the printing process is started, in step 101, print range data in the directions of the first and second axes and height data in the direction of the third axis of the surface to be printed of the material to be printed S are obtained (S101). The printing range data in the directions of the first and second axes and the height data in the direction of the third axis of the printing target surface of the printing material S are recorded in the storage unit 50 as image data received from the external device.

In step 102, based on the height data in the third axis direction of the printing material S acquired in step 101, the main scanning in the first axis direction and the sub-scanning in the second axis direction are performed. A total amount of the head gap G in the third axis direction on the entire surface is calculated (S102). Then, in step 103, the average value of the head gap G over the entire print area is calculated with respect to the total amount of the head gap G calculated in step 102 (S103).

In step 104, the moving scanning path that minimizes the average value of the head gap G calculated in step 103 is estimated (S104). Here, the moving scanning path that minimizes the average value of the head gap G is optimized by comparing the average values of the head gap G in a plurality of paths when moving and scanning while rotating the carriage 42 around the third axis. . Then, in step 105, while rotating the carriage 42 around the third axis, the printing process is performed on the entire print area along the moving scanning path estimated in step 104 by simultaneously moving and scanning in the directions of the first and second axes ( S105).

Note that the total amount of the head gap G in the third axis direction is calculated for a specific surface to be printed, and the moving scanning path that minimizes the calculated average value of the head gap G is estimated. The printing process may be performed along the estimated moving scanning path while rotating around the axis. Here, the specific surface to be printed includes an area where the height data of the printing material S in the third axis direction varies greatly compared to other print areas.
In this way, in the area where the height data of the printing material S in the third axis direction varies greatly compared to the other printing areas, the average value of the head gap G is estimated to be the smallest, and the movement scanning path is estimated. By performing print processing along the estimated moving scanning path while rotating 42 about the third axis, it is possible to suppress deterioration in image quality of a specific surface to be printed while suppressing a decrease in productivity.

In addition, the total amount of the head gap G in the third axis direction over the entire print area of the print target surface is calculated, and the movement scanning path in which the maximum value of the head gap G is within a predetermined distance is estimated, and the carriage 42 is moved. The printing process may be performed along the estimated moving scanning path while rotating around the third axis.
As schematically shown in FIG. 8, the head gap G, which is the distance to the surface to be printed directly below the nozzle rows 411 and 412 of the print head PH, varies greatly depending on the height data of the printing material S in the third axis direction. It becomes larger in the area X1 where the current is (see G2 in FIG. 8). When the print head moving mechanism 44 is driven so that the head gap G2 at this time is always kept at an appropriate distance that does not deteriorate the print quality (indicated by the arrow in FIG. 8), the printing process can be speeded up and quiet. And there is a possibility that energy saving may be hindered. In the present embodiment, a movement scanning path is estimated within the maximum permissible value that does not deteriorate the print quality as a predetermined distance of the head gap G, and the movement scanning is estimated while rotating the carriage 42 around the third axis. By performing print processing on the path, the time required for printing can be shortened.

(2.2) Movement Time Control FIG. 9 is a flow chart showing the flow of movement scanning control for shortening the movement time of the carriage 42 in this embodiment. In this embodiment, the carriage 42 is rotated around the third axis that intersects the first and second axes, and is controlled to minimize the movement scanning time of the carriage 42 . When printing is performed while maintaining a constant head gap G on the printing target surface of the printing material S having a three-dimensional shape, the undulation amount of the height data of the printing material S in the third axis direction is gentler, the print head The amount of movement in the direction of the third axis is small, and the amount of movement of the print head moving mechanism 44 can be reduced to speed up the printing process. The amount of movement of the carriage 42, including movement in the area outside the surface to be printed, differs depending on the planar shape of the surface to be printed of the printing material S. By moving and scanning in the direction, it is possible to speed up the printing process.

When the printing process is started, in step 201, print range data in the directions of the first and second axes and height data in the direction of the third axis of the surface to be printed of the printing material S are obtained (S201). The printing range data in the directions of the first and second axes and the height data in the direction of the third axis of the printing target surface of the printing material S are recorded in the storage unit 50 as image data received from the external device.

In step 202, based on the printing range data in the directions of the first and second axes and the height data in the direction of the third axis of the surface to be printed of the printing material S acquired in step 201, main scanning in the direction of the first axis, The total amount of movement of the carriage 42 and the total amount of movement of the print head PH in the direction of the third axis over the entire printing area of the surface to be printed when sub-scanning is performed in two axial directions are calculated (S202).

In step 203, the movement scanning path that minimizes the total amount of movement of the carriage 42 and the total amount of movement of the print head PH calculated in step 202 is estimated (S203). Then, in step 204, while rotating the carriage 42 around the third axis, the printing process is performed on the entire print area along the movement scanning path estimated in step 203 by simultaneously moving and scanning in the directions of the first axis and the second axis (S204). ). As a result, the time required for the printing process can be shortened according to the planar shape and the three-dimensional shape of the object S to be printed.

(2.3) Selection of Print Mode FIG. 10 is a flow chart showing the flow of control for movement and scanning of the carriage 42 for selecting the print mode in this embodiment. In this embodiment, the head gap G is smaller than usual, and the first print mode is capable of printing with high image quality. A print mode can be selected, and based on the print mode received via the operation display unit 30, the control unit 10 rotates the carriage 42 about the third axis while simultaneously rotating the carriage 42 in the first and second axis directions. A print process is performed on the print area by moving and scanning.

When print processing is started, selection of a print mode is accepted in step 301 (S301). The print modes to be selected are the first print mode in which the head gap G is smaller than usual and capable of printing with high image quality, and the second print mode in which the movement scanning time of the carriage 42 with respect to the print area is the shortest and the productivity is high. 2 print modes.

When the first print mode is selected in step 301, first, in step 302, print range data in the directions of the first and second axes and height data in the direction of the third axis of the surface to be printed of the printing material S are acquired. (S302). Then, in step 303, based on the height data of the printing material S in the third axis direction calculated in step 302, the main scanning in the first axis direction and the sub-scanning in the second axis direction are performed on the surface to be printed. A head gap G in the third axial direction is calculated (S303). In step 304, a movement scanning path is estimated in which the head gap G is smaller than usual (S304). As for the moving scanning path in which the head gap G is smaller than usual, the moving scanning path that has the smallest head gap G when the carriage 42 is rotated around the third axis and scanned in a plurality of paths is selected. You may choose. Then, in step 305, while rotating the carriage 42 around the third axis, the printing process is performed on the entire print area along the moving scanning path estimated in step 304 by simultaneously moving and scanning in the directions of the first and second axes ( S305).

When the second print mode is selected in step 301, first, in step 306, print range data in the directions of the first and second axes and height data in the direction of the third axis of the surface to be printed of the printing material S are obtained. (S306). Then, in step 307, based on the printing range data in the directions of the first and second axes and the height data in the direction of the third axis of the surface to be printed of the printing material S acquired in step 306, main scanning is performed in the direction of the first axis. , the total amount of movement of the carriage 42 and the total amount of movement of the print head in the direction of the third axis over the entire printing area of the surface to be printed when sub-scanning is performed in the direction of the second axis (S307).
In step 308, the movement scanning path that minimizes the total amount of movement of the carriage 42 and the total amount of movement of the print head PH calculated in step 307 is estimated (S308). Here, the movement scanning path that minimizes the total movement amount of the print head PH is optimized by comparing the total movement amount of the print head PH in a plurality of paths when moving and scanning while rotating the carriage 42 around the third axis. be done. Then, in step 309, while rotating the carriage 42 around the third axis, the printing process is performed on the entire print area along the movement scanning path estimated in step 308 by simultaneously moving and scanning in the directions of the first and second axes ( S309).

"Second Embodiment"
FIG. 11 is a block diagram showing an example of the hardware configuration of the printing apparatus 1A according to this embodiment, and FIG. 12 is a schematic diagram showing printing on a printing target surface inclined with respect to the reference plane.
The printing apparatus 1A according to the present embodiment includes a swing mechanism 46 as swing means for tilting the print head PH so that the nozzles NZ of each print head PH face the surface to be printed. The printing apparatus 1 differs from the printing apparatus 1 according to the first embodiment in that the head PH is tilted with respect to the print target surface and the head gap G, which is the distance between the print target surface and the print head PH, is adjusted. Therefore, the same reference numerals are given to the parts that perform the functions common to those of the first embodiment, and detailed description thereof will be omitted.

(1) Configuration of Printing Apparatus In a printing apparatus 1A according to the present embodiment, a printing mechanism 40A includes a carriage moving mechanism 43 for moving a carriage 42 in the first axis (width) and second axis (depth) directions, and a carriage 42. In addition to a printhead moving mechanism 44 for moving each arranged printhead in the direction of the third axis and a carriage rotation mechanism 45 for rotating the carriage 42 around the third axis, each printhead PH within the carriage 42 A print head swinging mechanism 46 tilts the print head PH in the direction of movement of the carriage 42 or in a direction crossing the direction of movement of the carriage 42 so that the nozzles NZ of the print head face the surface to be printed.
The print head swinging mechanism 46 is composed of a servo motor SM and a harmonic reducer HG (not shown), and tilts each print head PH in the direction of movement of the carriage 42 and in a direction intersecting the direction of movement of the carriage 42. The nozzles NZ of the print head PH are directed to the surface to be printed.

In FIG. 12, the ink droplets ejected from the nozzles NZ due to the inclination of the entire print head with respect to the surface to be printed, which is inclined with respect to the reference plane L formed by the first axis and the second axis, are shown on the surface to be printed. It shows a state in which the bullet hits from the normal direction.
For example, in FIG. 12A, when the surface to be printed is tilted 45 degrees with respect to the reference plane L in the moving direction of the carriage 42 (see the arrow in the figure), the print head is positioned on the surface to be printed with a thickness D of the print head. , and the head gap G cannot be reduced to less than 1/2 of the thickness D of the print head. In this way, the entire print head is tilted in the moving direction of the carriage 42 with respect to the surface to be printed which is inclined with respect to the reference plane L, and the print head PH and the surface to be printed are moved and scanned (indicated by the dashed line in the figure). It is possible to reduce the head gap G (G<D/2 in the figure) as compared with the case where the print head is not tilted while preventing the interference of the print head.

Also, as shown in FIG. 12B, when the surface to be printed is tilted in the direction intersecting the moving direction of the carriage 42, the entire print head is tilted in the direction intersecting the moving direction of the carriage 42 (see FIG. 12B). It is possible to reduce the head gap G compared to the case where the print head PH is not tilted (indicated by the solid line in the figure) while preventing interference between the print head PH and the surface to be printed. becomes.
When the entire print head is tilted with respect to the surface to be printed and is moved and scanned, the UV lamp row 430 or the IR lamp row 440 arranged in parallel with the print head PH on the carriage 42 is also tilted with respect to the surface to be printed. Fixing is preferred.

(2) Head Gap Control FIG. 13 is a flow chart showing the flow of control for moving and scanning the carriage 42 in this embodiment.
In this embodiment, when the surface to be printed is tilted with respect to the reference plane L formed by the first axis and the second axis, each print head PH is tilted in the movement direction of the carriage 42 so that the surface to be printed is tilted. The tilt angle of the print head is adjusted so that the average value of the head gap G over the entire print area of 1 is minimized. As a result, it is possible to shorten the time required for the printing process while suppressing deterioration in printing accuracy.

When the printing process is started, in step 401, print range data in the directions of the first and second axes and height data in the direction of the third axis of the surface to be printed of the material to be printed S are acquired (S401).

In step 402, the total amount of the head gap G in the direction of the third axis is calculated based on the height data of the printing material S in the direction of the third axis obtained in step 401 (S402). Then, in step 403, the average value of the head gap G in the print area is calculated with respect to the total amount of the head gap G calculated in step 402 (S403).

In step 404, the moving scanning path that minimizes the average value of the head gap G calculated in step 403 is estimated (S404). The movement scanning path that minimizes the average value of the head gap G is the movement that is optimized by comparing the average values of the head gap G in a plurality of paths when the carriage 42 is rotated around the third axis and scanned. estimated as a scanning path. Then, in step 405, the print head PH is tilted in the movement direction of the carriage 42, and printing is performed along the movement scanning path estimated in step 404 (S405).
Here, if the surface to be printed is tilted in the direction intersecting the moving direction of the carriage 42, the print head PH is tilted in the direction intersecting the moving direction of the carriage 42 so that the average value of the head gap G is minimized. print processing.

On a specific surface to be printed, the total amount of the head gap G in the direction of the third axis is calculated, the moving scanning path that minimizes the calculated average value of the head gap G is estimated, and the print head PH is moved to the carriage. 42, or tilted in a direction intersecting the movement direction of the carriage 42, and printing on the estimated movement scanning path. Here, the specific surface of the surface to be printed includes an area where the height data of the printing material S in the third axis direction varies greatly compared to other print areas.
In this way, in the area where the height data of the printing material S in the third axis direction varies greatly compared to other printing areas, the movement scanning path that minimizes the average value of the head gap is estimated, and the print head By performing print processing on a movement scanning path estimated by tilting the PH in the movement direction of the carriage 42 or in a direction intersecting the movement direction of the carriage 42, the time required for print processing is shortened while suppressing deterioration in printing accuracy. be able to.

In addition, the total amount of the head gap G in the third axis direction over the entire print area of the print target surface is calculated, and the movement scanning path in which the maximum value of the head gap G is within a predetermined distance is estimated, and the print head PH may be tilted in the direction of movement of the carriage 42 or in a direction intersecting the direction of movement of the carriage 42, and print processing may be performed on the estimated movement scanning path.
A head gap G, which is the distance between the printing target surface and the print head PH, becomes large in a region where the height data of the printing material S in the third axis direction changes greatly. If the print head swing mechanism 46 is driven so that the head gap G at this time is always kept at an appropriate distance that does not degrade the print quality, there is a risk that speeding up the printing process will be hindered.
In this embodiment, the print head PH is moved in the movement direction of the carriage 42 or in the movement of the carriage 42 by estimating a movement scanning path within the maximum allowable value that does not degrade the print quality as a predetermined distance of the head gap G. It is possible to shorten the time required for printing by performing the printing process on the moving scanning path estimated by tilting in the direction intersecting the direction.

As described above, in the present embodiment, the carriage 42 is supported by the frame F straddling the material to be printed S fixed on the mounting surface of the stage 41 in the first axis direction. Although the printing apparatus has been described as a gate-type configuration that can move in the second axial direction with respect to the stage 41 while straddling the two directions, the printing material S moves on the stage 41 in the second axial direction. good too.
Further, the carriage 42 may be moved and scanned by being held by a robot arm that is movable in the directions of the first, second and third axes and rotatable around the third axis.

REFERENCE SIGNS LIST 1, 1A printing device 10 control unit 20 communication unit 30 operation display unit 40 printing mechanism 41 stage, 42 carriage, 43 carriage Movement Mechanism 44 Print Head Movement Mechanism 45 Rotation Mechanism 46 Swing Mechanism 410 Print Head 420 Ink Tank
430: UV lamp row, 440: IR lamp row,
450... Oxygen degassing device, 460... Nitrogen replacement device,
470 Mist suction device 50 Storage unit

Claims (20)

a head that forms an image by ejecting ink droplets facing a printing target surface of a printing material having a three-dimensional shape fixed on a mounting surface of a stage;
The head is held facing the surface to be printed from a first axis perpendicular to the mounting surface of the stage and perpendicular to each other, and a third axis perpendicular to the second axis. a carriage movable in each direction of the first axis and the second axis;
While adjusting the head gap, which is the distance to the surface to be printed directly under the nozzle row of the head, the maximum value of the head gap over the entire print area of the surface to be printed is within a predetermined distance. a control means for rotating the carriage around the third axis to simultaneously move the carriage in each direction of the first axis and the second axis to control ejection of the ink droplets;
A printing device characterized by: a head that forms an image by ejecting ink droplets facing a printing target surface of a printing material having a three-dimensional shape fixed on a mounting surface of a stage;
The head is held facing the surface to be printed from a first axis perpendicular to the mounting surface of the stage and perpendicular to each other, and a third axis perpendicular to the second axis. a carriage movable in each direction of the first axis and the second axis;
While adjusting the head gap, which is the distance to the surface to be printed directly under the nozzle rows of the head, the carriage is moved to the third position so that the average value of the head gaps over the entire print area of the surface to be printed is minimized. a control means for rotating about an axis and simultaneously moving in each direction of the first axis and the second axis to control ejection of the ink droplets ;
A printing device characterized by: a head that forms an image by ejecting ink droplets facing a printing target surface of a printing material having a three-dimensional shape fixed on a mounting surface of a stage;
The head is held facing the surface to be printed from a first axis perpendicular to the mounting surface of the stage and perpendicular to each other, and a third axis perpendicular to the second axis. a carriage movable in each direction of the first axis and the second axis;
While adjusting the head gap, which is the distance to the surface to be printed directly under the nozzle rows of the head, the carriage is moved to the third position so that the average value of the head gap on a specific surface of the surface to be printed is minimized. a control means for rotating about an axis and simultaneously moving in each direction of the first axis and the second axis to control ejection of the ink droplets ;
A printing device characterized by: A first print mode in which the head gap is smaller than usual and a second print mode in which the carriage movement time is the shortest can be selected, and the control means controls the print mode based on the selected print mode. set the rotation angle of the carriage,
4. The printing apparatus according to any one of claims 1 to 3 , characterized in that: further comprising swing means for tilting the head so as to face the surface to be printed,
5. The printing apparatus according to any one of claims 1 to 4 , characterized in that: the surface to be printed is inclined with respect to a reference plane formed by the first axis and the second axis;
6. The printing apparatus according to claim 5 , wherein: The oscillating means tilts the head in the moving direction of the carriage to adjust the average value of the head gap over the entire print area of the print target surface to be the smallest.
7. The printing apparatus according to claim 5 or 6 , characterized in that: The oscillating means tilts the head in the moving direction of the carriage and adjusts the average value of the head gap on a specific surface of the surface to be printed to be the smallest.
7. The printing apparatus according to claim 5 or 6 , characterized in that: The oscillating means tilts the head in the moving direction of the carriage and adjusts the maximum value of the head gap over the entire print area of the print target surface to be within a predetermined distance.
7. The printing apparatus according to claim 5 or 6 , characterized in that: The oscillating means tilts the head in a direction intersecting the movement direction of the carriage to adjust the average value of the head gap over the entire print area of the print target surface to be the smallest.
7. The printing apparatus according to claim 5 or 6 , characterized in that: The oscillating means tilts the head in a direction intersecting the movement direction of the carriage to adjust the average value of the head gap on a specific surface of the printing target surface to be the smallest.
7. The printing apparatus according to claim 5 or 6 , characterized in that: The oscillating means tilts the head in a direction intersecting the moving direction of the carriage, and adjusts the maximum value of the head gap over the entire print area of the print target surface to be within a predetermined distance.
7. The printing apparatus according to claim 5 or 6 , characterized in that: The head has nozzles for ejecting the ink droplets extending in a direction intersecting the moving direction of the carriage to form a nozzle row. A plurality of types of heads including a color head are arranged side by side in the movement direction of the carriage,
The printing apparatus according to any one of claims 1 to 12, characterized in that: The plurality of types of heads include a primer head that ejects adhesive ink droplets, a white head that ejects white ink droplets that form a base layer, a special color head that ejects special color ink, and ink droplets that protect the surface of the image. including at least one of the ejecting topcoat heads;
The printing apparatus according to claim 13 , characterized in that: At least one of the spot color heads is arranged side by side in a direction intersecting with the moving direction of the carriage,
The printing apparatus according to claim 14 , characterized in that: The carriage is provided with a UV lamp row that irradiates ultraviolet rays to cure the ink droplets, or an IR lamp row that irradiates infrared rays to dry the ink droplets.
The printing apparatus according to any one of claims 13 to 15 , characterized in that: The process color head, the spot color head, the primer head, the white head, the top coat head and the UV lamp row, or the IR lamp row are individually arranged in the third axial direction with respect to the printing target surface. movably arranged
17. The printing apparatus according to claim 16 , characterized in that: The carriage has mist suction means for sucking gas containing mist of the ink droplets.
18. The printing apparatus according to any one of claims 1 to 17 , characterized in that: The carriage has degassing means for removing oxygen in the ink that forms the ink droplets.
19. The printing apparatus according to any one of claims 1 to 18 , characterized in that: The carriage has a nitrogen replacement mechanism that removes oxygen by introducing nitrogen gas into an atmosphere from when the ink droplets are ejected until they land on the surface to be printed and are cured.
20. A printing apparatus according to any one of claims 1 to 19 , characterized in that:

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