Printing apparatus

A printing unit includes a plurality of ink jet parts and an X-axis linear motion mechanism that moves each of the plurality of ink jet parts in the same main scanning direction. The X-axis linear motion mechanism moves the ink jet part involved in printing the workpiece among the plurality of ink jet parts so as to face the surface of the workpiece and moves the remaining ink jet part on the one X-axis linear motion mechanism so as to retreat from the surface of the workpiece. As a result, a printing apparatus that is capable of printing accurately onto the workpiece having a three-dimensional curved surface is provided.

BACKGROUND

1. Technical Field

The present disclosure relates to a printing apparatus.

2. Description of the Related Art

In the related art, a printing apparatus for printing on a workpiece having a curved surface by using an ink jet is known, for example, in Japanese Patent No. 6426038 (hereinafter referred to as “Patent Literature 1”).

Patent Literature 1 discloses a printing apparatus having a configuration in which an ink droplet is discharged by tilting a nozzle row in a sub scanning direction with respect to a side surface of a workpiece having a cylindrical shape body whose axial direction is a main scanning direction of an ink jet head.

However, the printing apparatus of Patent Literature 1 is limited to those in which the cross-sectional shape of the workpiece that can be printed is a cylindrical shape body. Therefore, there is a demand for a printing apparatus capable of printing with high accuracy even on a workpiece having any three-dimensional curved surface, not limited to a workpiece having a cylindrical shape body.

SUMMARY

The present disclosure provides a printing apparatus capable of printing a predetermined image with high accuracy by discharging droplets onto a workpiece having a three-dimensional curved surface according to the configuration indicated below.

That is, the printing apparatus of the present disclosure includes a printing unit that discharges ink onto a surface of the workpiece and a workpiece drive unit that adjusts a position of the workpiece. The printing unit includes a plurality of ink jet parts that discharge the ink and a main scanning linear motion mechanism that moves each of the plurality of ink jet parts in a same main scanning direction.

According to this configuration, the main scanning linear motion mechanism moves each of the plurality of ink jet parts in the same main scanning direction. That is, the main scanning linear motion mechanism moves each of the plurality of ink jet parts independently along the main scanning direction. As a result, for example, a printing apparatus capable of printing with a high degree of freedom can be obtained even on a workpiece having a recessed surface or a projection surface.

Further, the main scanning linear motion mechanism of the printing apparatus of the present disclosure moves the ink jet part involved in printing the workpiece among the plurality of ink jet parts so as to face the surface of the workpiece and moves one or more remaining ink jet parts among the plurality of ink jet parts to retreat from the surface of the workpiece.

According to this configuration, printing is performed with only the ink jet part involved in the printing facing the surface of the workpiece. On the other hand, the ink jet part that is not involved in the printing is configured to retreat from the workpiece so as not to interfere with the workpiece. As a result, the degree of freedom in a position adjustment motion of the workpiece can be increased.

Further, the printing unit of the printing apparatus of the present disclosure includes a sub scanning linear motion mechanism that moves at least one of the plurality of ink jet parts in a sub scanning direction intersecting with the main scanning direction.

According to this configuration, at least one of the plurality of ink jet parts is configured to be movable in the sub scanning direction. That is, only the ink jet part of the color that is a printing target is printed close to the workpiece. Therefore, interference between the workpiece and the ink jet part of other colors that are not the printing target can be prevented. As a result, the degree of freedom in a position adjustment motion of the workpiece can be increased.

Further, the printing unit of the printing apparatus of the present disclosure includes a forward and backward linear motion mechanism that moves at least one of the plurality of ink jet parts forward and backward with respect to the workpiece.

According to this configuration, the forward and backward linear motion mechanism moves at least one of the plurality of ink jet parts forward and backward with respect to the workpiece. That is, the forward and backward linear motion mechanism prints only the ink jet part of the color that is a printing target close to the workpiece. Therefore, interference between the workpiece and the ink jet part of other colors that are not the printing target can be prevented. As a result, the degree of freedom in a position adjustment motion of the workpiece can be increased.

Further, the printing unit of the printing apparatus of the present disclosure includes a rotation mechanism that rotates at least one of the plurality of ink jet parts.

According to this configuration, the ink jet part is configured to be rotatably by a rotation mechanism. As a result, a nozzle position of the ink jet part with respect to the workpiece can be finely adjusted by the rotation mechanism while moving the ink jet part in the main scanning direction.

Specifically, the rotation mechanism, for example, forms the plurality of nozzle rows arranged in a row along the sub scanning direction of the ink jet part in a position inclined obliquely with respect to the main scanning direction. Thereby, the pitch between the plurality of nozzles arranged in a row can be reduced. As a result, the print resolution of the printing apparatus can be increased.

Further, the rotation mechanism rotates, for example, the nozzle row of the ink jet part by 90° with respect to the main scanning direction. Thereby, the printing direction with respect to the workpiece can be changed. As a result, the accuracy of ink landing onto the workpiece can be improved.

Further, the workpiece drive unit of the printing apparatus of the present disclosure includes drive mechanisms of at least four axes, and at least two axes of the drive mechanisms of four axes are configured by a rotation mechanism.

According to this configuration, the workpiece drive unit includes the drive mechanisms of at least four axes, and at least two axes thereof are configured by a rotation mechanism. As a result, the adjustment range of the position of the workpiece can be widened. Therefore, the position adjustment according to the curved surface of the workpiece can be speeded up, and the workpiece can be printed with high accuracy.

Further, the main scanning linear motion mechanism of the printing apparatus of the present disclosure includes a first main scanning linear motion mechanism and a second main scanning linear motion mechanism arranged in parallel to each other. The plurality of ink jet parts are arranged in a row along the main scanning direction, and are alternately attached to the first main scanning linear motion mechanism and the second main scanning linear motion mechanism.

According to this configuration, the first main scanning linear motion mechanism and the second main scanning linear motion mechanism are arranged in parallel to each other. The plurality of ink jet parts are arranged in a row along the main scanning direction, and are alternately attached to the first main scanning linear motion mechanism and the second main scanning linear motion mechanism. Thereby, a gap between the ink jet part attached to the first main scanning linear motion mechanism and the ink jet part attached to the second main scanning linear motion mechanism can be set small. As a result, the entire length of the printing apparatus in the main scanning direction can be reduced.

According to the present disclosure, it is possible to provide a printing apparatus capable of printing accurately on a workpiece having a three-dimensional curved surface.

DETAILED DESCRIPTION

Hereinafter, exemplary embodiments of the present disclosure will be described based on the drawings. The following description of the desired exemplary embodiments is essentially merely an example and is not intended to limit the present disclosure, application of the disclosure, or use of the disclosure.

Hereinafter, a schematic configuration of printing apparatus1of Exemplary Embodiment 1 of the present disclosure will be described based onFIGS. 1 to 3.

FIG. 1is a front view illustrating a schematic configuration of printing apparatus1according to Exemplary Embodiment 1.FIG. 2is a side view illustrating a schematic configuration of printing apparatus1.FIG. 3is a side view illustrating a schematic configuration when a position of workpiece W of printing apparatus1is changed.

As illustrated inFIGS. 1 to 3, printing apparatus1of Exemplary Embodiment 1 is an apparatus that prints a predetermined image by discharging droplet25such as ink or a coating material onto workpiece W having a three-dimensional curved surface. Workpiece W is formed of, for example, a resin molded product or the like.

Printing apparatus1of Exemplary Embodiment 1 is configured as described above.

Hereinafter, printing apparatus1of Exemplary Embodiment 1 will be described by dividing printing apparatus1into terms for each component.

Printing Unit

First, a configuration of printing unit10of printing apparatus1will be described.

As illustrated inFIG. 1, printing unit10is disposed more upward than a printing surface of workpiece W. Printing unit10includes X-axis linear motion mechanism11(sometimes referred to as a “main scanning linear motion mechanism”) which is a drive mechanism of one axis, a plurality of ink jet parts20, and the like.

The X-axis linear motion mechanism11is attached to gantry3. Each of the plurality of ink jet parts20is attached to X-axis linear motion mechanism11. X-axis linear motion mechanism11moves each of the plurality of ink jet parts20in the same main scanning direction (inFIG. 1, the horizontal direction (X direction)).

Specifically, X-axis linear motion mechanism11is configured by a linear motor type drive mechanism. X-axis linear motion mechanism11drives each of the plurality of ink jet parts20individually in the X direction. As a result, X-axis linear motion mechanism11drives only ink jet part20that is involved in printing among the plurality of ink jet parts20so as to face a surface of workpiece W. At the same time, X-axis linear motion mechanism11drives ink jet part20that is not involved in the printing so as to retreat from workpiece W.

Specifically, at least four ink jet parts20are provided, for example, corresponding to four colors of cyan (C), magenta (M), yellow (Y), and black (K).

Ink jet part20discharges droplet25toward workpiece W while moving in the main scanning direction. Ink jet part20prints an image on the surface of workpiece W with discharged droplet25. At this time, workpiece drive unit30further relatively moves workpiece W with respect to ink jet part20as illustrated inFIG. 3. As a result, the image can be printed in a sub scanning direction (inFIG. 2, the horizontal direction (Y direction)) which is orthogonal to the main scanning direction.

Next, ink jet part20of printing unit10will be described with reference toFIG. 4.FIG. 4is a plan view illustrating a configuration of ink jet part20of printing apparatus1.

As illustrated inFIG. 4, ink jet part20includes head part21and curing part23. Head part21is provided with four nozzle rows arranged at predetermined intervals in the X direction. The nozzle row includes a plurality of nozzles22arranged in one row along the sub scanning direction (Y direction). A pitch between nozzles22adjacent to each other in the X direction is set to, for example, 150 dpi to 1200 dpi. A nozzle row having a plurality of nozzles22may be arranged side by side in two or more rows along the sub scanning direction.

In the example illustrated inFIG. 4, in order to explain the pitch between nozzles22in an easy-to-understand manner, an example is illustrated in which the plurality of nozzles22in the four nozzle rows are arranged side by side at the same position (overlapping position) when viewed from the printing direction, but the present disclosure is not limited to this. For example, the plurality of nozzles22in the four nozzle rows may be arranged with being shifted at positions where the plurality of nozzles22do not overlap each other when viewed from the printing direction. As a result, the resolution of printing can be increased.

Ink jet part20is configured by, for example, a piezo type device. Ink jet part20discharges a predetermined amount of droplets25vertically downward from nozzle22, for example, toward the surface of workpiece W, in response to a drive signal supplied from controller15.

In curing part23, the ink or the coating material which is applied to the surface of workpiece W is cured. As curing part23, it is appropriately selected from the following devices and the like depending on the type of ink and coating material to be applied. For example, as curing part23, an ultraviolet light source such as a metal halide lamp or UV-LED, an infrared light source such as a halogen lamp, an infrared laser diode, or an infrared laser, a heat source by a heater, or the like can be used.

In Exemplary Embodiment 1, as illustrated inFIG. 4, the configuration in which ink jet part20includes head part21and one curing part23has been described as an example, but the present disclosure is not limited to this.

For example, as illustrated inFIG. 5, ink jet part20may include head part21, and two curing parts23which are disposed on both sides of head part21in the main scanning direction (inFIG. 5, the horizontal direction (X direction)). With this configuration, the ink on workpiece W can be efficiently cured by using two curing parts23during a reciprocating motion of ink jet part20with respect to workpiece W.

Further, as illustrated inFIG. 6, ink jet part20may include head part21, curing part23, and distance measurement part24. Distance measurement part24measures a distance between ink jet part20and workpiece W. Distance measurement part24is appropriately selected depending on the type of material constituting workpiece W. For example, as distance measurement part24, a contact type probe, a non-contact type laser displacement meter, an ultrasonic displacement meter, an LED, or the like can be used. Distance measurement part24with the above described non-contact type measures a distance based on the time from when workpiece W is irradiated with light until the light returns to a light receiving element (not illustrated).

At this time, printing unit10of Exemplary Embodiment 1 is configured so as to measure a distance between workpiece W and printing unit10by distance measurement part24before printing by discharging droplet25onto workpiece W for the following reasons.

That is, when workpiece W is made of, for example, a resin molded product, a dimensional difference of ±1 mm or more may occur between workpiece W and printing unit10with respect to designed CAD data of a product.

Therefore, in printing unit10of Exemplary Embodiment 1, the distance between ink jet part20and workpiece W is measured in advance by distance measurement part24. As a result, it is possible to prevent a collision between ink jet part20and workpiece W during printing in advance. Further, a printing gap, which is a distance that droplet25can reach reliably, can be appropriately set in advance.

In addition to measuring the distance between above described ink jet part20and workpiece W, a shape of workpiece W may be measured and the shape of workpiece W may be converted into surface data of workpiece W based on the measurement data of the shape by distance measurement part24. As a result, the surface data of workpiece W can be used for the printing. Further, distance measurement part24may measure only a representative point of an area to be printed and appropriately change the printing gap based on information of the representative point. As a result, the time required for printing can be shortened.

The measurement of the distance between workpiece W and printing unit10may be obtained with the total number of components to be printed or may be performed by extracting the components to be printed. When workpiece W is made of a material having excellent dimensional stability, it is not necessary to particularly perform the measurement of the distance described above.

Further, as illustrated inFIG. 7, ink jet part20may include only head part21and distance measurement part24.

Ink jet part20may be configured such that curing part23and distance measurement part24are not provided, and only head part21is provided alone. As a result, the curved surface that ink jet part20can handle increases, the weight of ink jet part20can be reduced, and the device configuration can be simplified.

Ink jet part20may have a configuration having a plurality of head parts21. In the case of a configuration having a plurality of head parts21, not all head parts21need to have different colors, and a plurality of head parts21having the same color may be provided. As a result, for example, the amount of white ink that hides the base that is used in a large amount can be increased as compared with the inks of other colors, and the usage time can be extended. Further, when the curved surface is printed by two head parts21of the same color, the tact becomes shorter.

For example, it may be configured to further include ink jet part20of another color, so-called special color, such as light cyan (Lc) or light magenta (Lm) for improving the graininess of an image, green (G), orange (Or), red (R), or violet (V) for expanding the color reproduction region. As a result, the expressiveness of a product package to be printed or the appeal of the product can be improved. Further, it may be configured to add a plurality of color nozzle rows to head part21of one ink jet part20. As a result, one head can handle a plurality of colors or materials, so that the size can be reduced.

When an image is formed on workpiece W of a medium whose base is not white, an ink jet part with white (W) is usually required. In this case, for example, the ink jet part with white (W) may be disposed separately from ink jet part20having four colors.

An ink jet part for a primer may be provided in order to impart adhesion to the base. An ink jet part for a clear may be provided in order to form an uneven texture or to form a protective layer on the coated color. Further, an ink jet part for a metallic material containing aluminum, gold, silver, copper, and the like may be provided. These ink jet parts do not necessarily have to be provided and may be appropriately disposed as needed. Examples of the desired combination of the ink jet parts described above include (1) cyan, magenta, yellow, and black, (2) white, cyan, magenta, yellow, and black, (3) white, cyan, magenta, yellow, black, and clear, (4) primer, cyan, magenta, yellow, black, and clear, (5) metallic, white, cyan, magenta, yellow, and black, and the like. Further, examples of the combinations include (6) white, cyan, magenta, yellow, black, light cyan, and light magenta, (7) primer, white, cyan, magenta, yellow, black, and clear, and the like. Furthermore, examples of the combinations include (8) metallic, white, cyan, magenta, yellow, black, and clear, (9) metallic, white, cyan, magenta, yellow, black, light cyan, and light magenta, (10) metallic, white, cyan, magenta, yellow, black, light cyan, light magenta, and clear, and the like.

The ink or the coating material of each of the above colors is made of, for example, a material that is cured by ultraviolet rays (UV). The ink or the coating material for a primer or a clear may be an ultraviolet type or a solvent type. Further, the ink or the coating material of the metallic material may be an ultraviolet type or a solvent type.

As described above, the ink or the coating material of each color is desirably a material that is cured by the ultraviolet rays (UV), but may be a solvent type. That is, the ink that hardens with ultraviolet rays enables drying in a short time. When it is a solvent type, the material can be easily designed, so that there is a possibility that more materials can be used to expand the applicable range.

Printing unit10of printing apparatus1is configured as described above.

Workpiece Drive Unit

Next, workpiece drive unit30of printing apparatus1will be described with reference toFIGS. 1 to 3.

As illustrated inFIGS. 1 to 3, workpiece drive unit30includes fixing jig40attached to a front end having a high degree of freedom of movement. Workpiece W is fixed to fixing jig40. Workpiece drive unit30transports workpiece W fixed to fixing jig40below printing unit10.

Workpiece drive unit30includes drive mechanisms of four axes. Two axes among the drive mechanisms of four axes are Y-axis linear motion mechanism31and Z-axis linear motion mechanism32. The other two axes among the drive mechanisms of four axes are A-axis rotation mechanism35and B-axis rotation mechanism36.

Y-axis linear motion mechanism31is mounted on frame2. Y-axis linear motion mechanism31moves workpiece W in the sub scanning direction (Y direction).

Z-axis linear motion mechanism32is attached to Y-axis linear motion mechanism31. Z-axis linear motion mechanism32moves workpiece W in the vertical direction (Z direction).

One end of A-axis rotation mechanism35is attached to Z-axis linear motion mechanism32, and supporting arm41is attached to the other end of A-axis rotation mechanism35. A-axis rotation mechanism35rotates workpiece W with the A-axis extending in the X direction from Z-axis linear motion mechanism32as the center of rotation via supporting arm41.

B-axis rotation mechanism36is attached to A-axis rotation mechanism35via supporting arm41. Fixing jig40is attached to B-axis rotation mechanism36. B-axis rotation mechanism36rotates workpiece W with the B-axis extending in the Z direction from supporting arm41as the center of rotation.

Workpiece drive unit30operates Y-axis linear motion mechanism31, Z-axis linear motion mechanism32, A-axis rotation mechanism35, and B-axis rotation mechanism36based on a signal from controller15. As a result, workpiece drive unit30moves workpiece W fixed to fixing jig40below ink jet part20. At this time, workpiece drive unit30moves workpiece W while adjusting a position and a position of workpiece W by using the drive mechanisms of four axes (seeFIG. 3).

Workpiece drive unit30of printing apparatus1is configured as described above and moves workpiece W.

Controller

Controller15is constituted by, for example, a personal computer, a programmable logic controller (PLC), or the like. Controller15controls the operations of printing unit10and workpiece drive unit30.

Specifically, controller15controls an operation of the plurality of ink jet parts20with respect to printing unit10via X-axis linear motion mechanism11. Further, controller15controls such that an appropriate amount of droplets25such as ink or coating material are discharged from head part21of ink jet part20of printing unit10.

Position and Orientation of Workpiece when Printing

Next, a position and an orientation of workpiece W when printing will be described with reference toFIG. 8.

As illustrated inFIG. 8, among the plurality of nozzles22of ink jet part20, a point where a perpendicular line drawn from nozzle22ain the vicinity of the center toward the surface of workpiece W intersects with the surface of workpiece W, is defined as intersection75. A point where a perpendicular line drawn from a point, in which a center line of head part21in the X direction and a center line of head part21in the Y direction intersect as illustrated by alternate long and short dash lines inFIG. 4, toward the surface of workpiece W intersects with the surface of workpiece W may be defined as intersection75. As a result, a center position of head part21can be set as a center position of the locus, and the calculation can be performed in consideration of symmetry. Therefore, a printing track can be easily calculated by using each of all the nozzle rows.

At intersection75, tangential line76with respect to the surface of workpiece W is parallel to a lower surface of ink jet part20(the surface on which nozzle22is disposed). A distance between nozzle22and the surface of workpiece W is defined as D.

As described above, controller15controls a drive of the drive mechanism which is constituted by Z-axis linear motion mechanism32, Y-axis linear motion mechanism31, A-axis rotation mechanism35, and B-axis rotation mechanism36. At this time, controller15controls the drive mechanism so that distance D1 between nozzle22ain the vicinity of the center and intersection75on the surface of workpiece W, which is illustrated inFIG. 8, is substantially constant (including constant), and adjusts the position and the orientation of workpiece W.

Distance D1 is set to any value in the range of, for example, 0.3 mm to 7 mm. As described above, this range is a range in which droplet25can be stably applied. Distance D1 is not limited to the above range and can be changed as needed, such as a curved surface of workpiece W or the printing accuracy.

However, usually, there are portions having different curvatures on the surface of workpiece W. Therefore, even when controller15adjusts distance D1 between nozzle22ain the vicinity of the center and intersection75on the surface of workpiece W to be substantially constant (including constant), the distance between nozzle22and the surface of workpiece W changes.

At this time, in a part where distance D between nozzle22and workpiece W is longer than a predetermined value, the time for droplet25to reach workpiece W becomes longer. Therefore, droplet25discharged from nozzle22is easily affected by the surrounding air flow and the like. As a result, a landing position of droplet25on workpiece W may shift, causing phenomena such as oozing, blurring, and color shift. That is, when droplet25cannot be accurately disposed at a predetermined position on a three-dimensional curved surface on the surface of workpiece W, the image quality of the printed image may deteriorate.

For example, a distance between left end nozzle22and workpiece W illustrated inFIG. 9is longer than a distance between left end nozzle22and workpiece W illustrated inFIG. 8. Therefore, it is necessary to adjust the coating width of the nozzle row according to the curvature of the surface of workpiece W and dispose droplet25with high accuracy.

Controller15sets a coating region according to the following procedure based on the CAD data and the like. After that, controller15applies droplet25to the surface of workpiece W by changing the coating width of the nozzle row for each set coating region via ink jet part20.

Hereinafter, the setting of the coating region will be specifically described with reference toFIGS. 10 to 14.

First, as illustrated inFIG. 10, controller15sets coating line50on the surface of workpiece W. At this time, it is desirable that coating line50is set at a part on the surface of workpiece W that is close to the plane having the smallest curvature. That is, the difference in distance D can be reduced. Therefore, by applying the droplets from a part having a small curvature, it is possible to print using a wide printing width.

Next, as illustrated inFIG. 11, controller15sets a plurality of print coordinates52divided into equal pitches51on set coating line50. Print coordinates52are calculated by using the CAD data according to the required necessary print resolution. At this time, for example, print coordinates52are desirably set at a pitch of the print resolution. Print coordinates52may be set at a pitch that is an integral multiple of the print resolution. As a result, it is possible to suppress an increase in the amount of data and shorten the printing time. Further, when it is set to an integral multiple, data complementation can be easily supplemented.

Next, controller15relatively moves ink jet part20with respect to workpiece W along set coating line50. Specifically, ink jet part20is relatively moved with respect to workpiece W so that the perpendicular line, which is drawn from nozzle22ain the vicinity of the center of head part21of ink jet part20toward the surface of workpiece W, coincides with print coordinates52. At this time, controller15moves workpiece W while adjusting the position and the orientation so that distance D between nozzle22and the surface of workpiece W is substantially constant (including constant).

Next, as illustrated inFIG. 12, controller15controls the drive mechanism such that the inclination of line segment53connecting print coordinates52that faces nozzle22and next print coordinates52is set to near 0 (zero) (parallel and horizontal to the nozzle surface), and moves and rotates workpiece W. As a result, workpiece W changes from a state illustrated inFIG. 11to a state illustrated inFIG. 12. InFIGS. 11 and 12, the tangential line of the curved surface at each of print coordinates52and the nozzle surface are parallel. The tangential line of the curved surface at print coordinates52is perpendicular to coating line50.

Next, controller15relatively moves ink jet part20with respect to all print coordinates52on set coating line50. After that, controller15selects only nozzle22whose distance D between nozzle22and the surface of workpiece W is within a certain range D2 at print coordinates52among the plurality of nozzles22(seeFIGS. 8 and 9). Specifically, controller15selects only nozzle22whose distance D from the surface of workpiece W is within 5 mm, for example.

At this time, as illustrated inFIG. 13, controller15sets a region that can be coated by selected nozzle22to first region55. Specifically, first region55is set in a region interposed between two lines parallel to coating line50.

Next, after first region55is set, controller15sets next coating line54at a position adjacent to first region55, as illustrated inFIG. 14. The above-mentioned process is repeated, and a region interposed between the two lines parallel to coating line54is set as second region56.

Further, controller15repeatedly sets the above process for a necessary coating region of workpiece W. After that, controller15applies droplet25for each set coating region via ink jet part20.

At this time, when the curvature of the surface of each of the coating regions is different, the widths of the coating regions are different. Therefore, the number of nozzles22to be selected will also be different. At that time, controller15controls distance D between nozzle22and the surface of workpiece W so as to be within a certain range (D2). As a result, droplet25can be accurately applied to the coating region within distance D2 within a certain range via ink jet part20.

When the coating region of workpiece W is divided into a plurality of regions, it is desirable to divide workpiece W so that no gap is formed between each of the coating regions. Therefore, controller15sets, for example, coating line54at an end portion of first region55. As a result, no gap is formed between first region55and second region56. However, even when a gap is formed between the coating regions, separately, another coating region may be provided so as to cover a part where the gap is formed, and then droplet25may be applied.

In the above description, when distance D between nozzle22and the surface of workpiece W is set, although the example described with reference to nozzle22ain the vicinity of the center among the plurality of nozzles22, another nozzle22may be used as a reference. For example, nozzles22disposed at both end portions of the nozzle row may be used as a reference. As a result, it is possible to set a region without a gap or a wide region in particular. Further, it may be configured such that droplet25is applied by using different nozzles22when setting the region and when coating. That is, for example, when a problem occurs in nozzle22that is used when setting a region, nozzle22that is used when setting a region is offset when coating instead of using nozzle22that is used when setting a region in the region. As a result, even when a problem occurs in nozzle22, it can be easily dealt with.

When the curvature of the surface of workpiece W is large, nozzle22which is used less frequently may be generated. In that case, it is desirable that nozzle22that is not used for a certain period of time is configured to perform dummy coating. As a result, unused nozzle22can be appropriately cleaned to properly maintain a state of nozzle22.

As described above, printing apparatus1of Exemplary Embodiment 1 can draw a pattern on workpiece W having a curved surface with high accuracy. That is, printing apparatus1of Exemplary Embodiment 1 can be used for forming a design for the external appearance of a product, drawing a wiring pattern on a three-dimensional surface, or the like.

Hereinafter, a schematic configuration of printing apparatus1of Exemplary Embodiment 2 of the present disclosure will be described based onFIG. 15.

FIG. 15is a side view illustrating a schematic configuration of printing apparatus1according to Exemplary Embodiment 2. Hereinafter, the same parts as those in Exemplary Embodiment 1 are designated by the same reference numerals, and only the differences will be described.

As illustrated inFIG. 15, printing unit10of printing apparatus1of Exemplary Embodiment 2 includes X-axis linear motion mechanism11which is a drive mechanism of one axis and a plurality of ink jet parts20.

Workpiece drive unit30includes drive mechanisms of four axes. Two axes among the drive mechanisms of four axes are Y-axis linear motion mechanism31and Z-axis linear motion mechanism32. The other two axes among the drive mechanisms of four axes are A-axis rotation mechanism35and B-axis rotation mechanism36.

One end of B-axis rotation mechanism36is attached to Z-axis linear motion mechanism32via first arm61. B-axis rotation mechanism36rotates workpiece W with the B-axis extending in the Y direction from Z-axis linear motion mechanism32as the center of rotation.

A-axis rotation mechanism35is attached to B-axis rotation mechanism36via second arm62. Fixing jig40is attached to A-axis rotation mechanism35via third arm63. A-axis rotation mechanism35rotates workpiece W with A-axis extending in the X direction from second arm62as the center of rotation.

With the configuration of workpiece drive unit30, among the plurality of ink jet parts20, only ink jet part20including a material that is a printing target can be printed close to workpiece W. As a result, it is possible to prevent the other ink jet part20from interfering with workpiece W. As a result, the degree of freedom in a position adjustment motion of workpiece W can be further increased.

Hereinafter, a schematic configuration of printing apparatus1of Exemplary Embodiment 3 of the present disclosure will be described based onFIG. 16.

FIG. 16is a side view illustrating a schematic configuration of printing apparatus1according to Exemplary Embodiment 3. Hereinafter, the same parts as those in Exemplary Embodiment 1 are designated by the same reference numerals, and only the differences will be described.

As illustrated inFIG. 16, printing unit10of printing apparatus1of Exemplary Embodiment 3 includes drive mechanisms of two axes and a plurality of ink jet parts20. The drive mechanisms of two axes includes X-axis linear motion mechanism11and a plurality of Y′-axis linear motion mechanisms13(sub scanning linear motion mechanism).

The plurality of Y′-axis linear motion mechanisms13are provided corresponding to each of the plurality of ink jet parts20. The plurality of Y′-axis linear motion mechanisms13are attached to X-axis linear motion mechanism11. Each of the plurality of ink jet parts20is attached to X-axis linear motion mechanism11via corresponding each of Y′-axis linear motion mechanisms13.

The plurality of Y′-axis linear motion mechanisms13move at least one of the plurality of ink jet parts20in the sub scanning direction (Y direction). That is, for example, among the plurality of ink jet parts20, only ink jet part20including the material (color, raw material, or the like) that is a printing target is moved in the sub scanning direction by the corresponding Y′-axis linear motion mechanism13.

Workpiece drive unit30includes drive mechanisms of four axes. Two axes among the drive mechanisms of four axes are Y-axis linear motion mechanism31and Z-axis linear motion mechanism32. The other two axes among the drive mechanisms of four axes are A-axis rotation mechanism35and B-axis rotation mechanism36.

With the configuration of Exemplary Embodiment 3, among the plurality of ink jet parts20, only ink jet part20including a material that is a printing target can be printed close to workpiece W. As a result, it is possible to prevent the other ink jet part20from interfering with workpiece W. As a result, the degree of freedom in a position adjustment motion of workpiece W can be further increased.

Hereinafter, a schematic configuration of printing apparatus1of Exemplary Embodiment 4 of the present disclosure will be described based onFIG. 17.

FIG. 17is a side view illustrating a schematic configuration of printing apparatus1according to Exemplary Embodiment 4. Hereinafter, the same parts as those in Exemplary Embodiment 1 are designated by the same reference numerals, and only the differences will be described.

As illustrated inFIG. 17, printing unit10of printing apparatus1of Exemplary Embodiment 4 includes drive mechanisms of two axes and a plurality of ink jet parts20. The drive mechanisms of two axes includes X-axis linear motion mechanism11and a plurality of Z′-axis linear motion mechanisms14(forward and backward linear motion mechanism).

The plurality of Z′-axis linear motion mechanisms14are provided corresponding to each of the plurality of ink jet parts20. The plurality of Z′-axis linear motion mechanisms14are attached to X-axis linear motion mechanism11. Each of the plurality of ink jet parts20is attached to X-axis linear motion mechanism11via corresponding each of Z′-axis linear motion mechanisms14.

The plurality of Z′-axis linear motion mechanisms14move at least one of the plurality of ink jet parts20forward and backward in the Z direction with respect to workpiece W. That is, for example, among the plurality of ink jet parts20, only ink jet part20including the material (color, raw material, or the like) that is a printing target is moved downward by the corresponding Z′-axis linear motion mechanism14.

Workpiece drive unit30includes drive mechanisms of four axes. Two axes among the drive mechanisms of four axes are Y-axis linear motion mechanism31and Z-axis linear motion mechanism32. The other two axes among the drive mechanisms of four axes are A-axis rotation mechanism35and B-axis rotation mechanism36.

With the configuration of Exemplary Embodiment 4, among the plurality of ink jet parts20, only ink jet part20including a material that is a printing target can be printed close to workpiece W. As a result, it is possible to prevent the other ink jet part20from interfering with workpiece W. As a result, the degree of freedom in a position adjustment motion of workpiece W can be further increased.

Further, even when the surface of workpiece W has a recessed portion, only the corresponding ink jet part20can be brought close to the recessed portion to discharge droplet25. As a result, it is possible to draw a pattern on workpiece W with high accuracy.

Hereinafter, a schematic configuration of printing apparatus1of Exemplary Embodiment 5 of the present disclosure will be described based onFIG. 18.

FIG. 18is a side view illustrating a schematic configuration of printing apparatus1according to Exemplary Embodiment 5. Hereinafter, the same parts as those in Exemplary Embodiment 1 are designated by the same reference numerals, and only the differences will be described.

As illustrated inFIG. 18, printing unit10of printing apparatus1of Exemplary Embodiment 4 includes drive mechanisms of two axes and a plurality of ink jet parts20. The drive mechanisms of two axes includes X-axis linear motion mechanism11and a plurality of C′-axis rotation mechanisms38.

The plurality of C′-axis rotation mechanisms38are provided corresponding to each of the plurality of ink jet parts20. The plurality of C′-axis rotation mechanisms38are attached to X-axis linear motion mechanism11. Each of the plurality of ink jet parts20is attached to X-axis linear motion mechanism11via corresponding each of C′-axis rotation mechanisms38. The C′-axis rotation mechanism38rotates head part21in the horizontal direction with C′-axis extending in the Z direction as the center of rotation.

Workpiece drive unit30includes drive mechanisms of four axes. Two axes among the drive mechanisms of four axes are Y-axis linear motion mechanism31and Z-axis linear motion mechanism32. The other two axes among the drive mechanisms of four axes are A-axis rotation mechanism35and B-axis rotation mechanism36.

According to the configuration of Exemplary Embodiment 5, ink jet part20can be moved in the main scanning direction by X-axis linear motion mechanism11and a position of nozzle22of head part21with respect to workpiece W can be finely adjusted in the horizontal direction by C′-axis rotation mechanism38.

Specifically, for example, rows of a plurality of nozzles22arranged in one row along the sub scanning direction of ink jet part20are formed in a position inclined obliquely with respect to the main scanning direction. As a result, the pitch between nozzles22can be reduced and the print resolution can be increased.

The printing direction can be changed by rotating the row of nozzles22of ink jet part20by 90° with respect to the main scanning direction. As a result, the landing accuracy of droplet25can be improved.

Hereinafter, a schematic configuration of printing apparatus1of Exemplary Embodiment 6 of the present disclosure will be described based onFIG. 19.

FIG. 19is a front view illustrating a schematic configuration of printing apparatus1according to Exemplary Embodiment 6. Hereinafter, the same parts as those in Exemplary Embodiment 1 are designated by the same reference numerals, and only the differences will be described.

As illustrated inFIG. 19, workpiece drive unit30of printing apparatus1of Exemplary Embodiment 6 includes drive mechanisms of four axes. Two axes among the drive mechanisms of four axes are Y-axis linear motion mechanism31and Z-axis linear motion mechanism32. The other two axes among the drive mechanisms of four axes are A-axis rotation mechanism35and B-axis rotation mechanism36.

Printing unit10includes X-axis linear motion mechanism11and a plurality of ink jet parts20.

X-axis linear motion mechanism11includes first X-axis linear motion mechanism11a(first main scanning linear motion mechanism) and second X-axis linear motion mechanism11b(second main scanning linear motion mechanism). First X-axis linear motion mechanism11aand second X-axis linear motion mechanism11bare disposed in parallel with each other in the X direction. First X-axis linear motion mechanism11ais disposed more upward than second X-axis linear motion mechanism11b.

For example, two ink jet parts20are attached to first X-axis linear motion mechanism11a. Specifically, ink jet part20is attached to first X-axis linear motion mechanism11avia first supporting member45.

First supporting member45includes horizontal part45aextending along first X-axis linear motion mechanism11ain the horizontal direction and vertical part45bextending downward from a left end portion of horizontal part45a. Ink jet part20is attached to a lower end portion of vertical part45b.

On the other hand, for example, two ink jet parts20are attached to second X-axis linear motion mechanism11b. Ink jet part20is attached to second X-axis linear motion mechanism11bvia second supporting member46. Second supporting member46extends along second X-axis linear motion mechanism11bin the horizontal direction.

Four ink jet parts20are arranged so as to line up in the X direction. Four ink jet parts20are alternately attached to first X-axis linear motion mechanism11aand second X-axis linear motion mechanism11b.

Specifically, ink jet part20which is first from the left inFIG. 19is attached to first X-axis linear motion mechanism11avia first supporting member45. Ink jet part20which is second from the left is attached to second X-axis linear motion mechanism11bvia second supporting member46.

Ink jet part20which is third from the left inFIG. 19is attached to first X-axis linear motion mechanism11avia first supporting member45. Ink jet part20which is fourth from the left is attached to second X-axis linear motion mechanism11bvia second supporting member46.

Each of the nozzle surfaces of four ink jet parts20is disposed at positions on substantially the same plane (including on the same plane).

With the above configuration, the entire length of printing apparatus1in the X direction can be reduced as described below with reference toFIG. 20.

That is, as illustrated in the upper part inFIG. 20, when X-axis linear motion mechanism11is in one row, each of four ink jet parts20is held by X-axis linear motion mechanism11by second supporting member46. Therefore, when four ink jet parts20are moved to the left side in a state where second supporting members46maintain gaps that do not interfere with each other, a distance between the center of ink jet part20positioned at the left end and the center of ink jet part20positioned at the right end is A1.

On the other hand, as illustrated in the lower part inFIG. 20, X-axis linear motion mechanism11of Exemplary Embodiment 6 is configured by two rows in which first X-axis linear motion mechanism11aand second X-axis linear motion mechanism11bare disposed in parallel with each other in the Z direction. Ink jet parts20which are first and third from the left are attached to first X-axis linear motion mechanism11avia first supporting member45. On the other hand, ink jet parts20which are second and fourth from the left are attached to second X-axis linear motion mechanism11bvia second supporting member46.

Vertical part45bof first supporting member45is configured to have a shape smaller than the horizontal width of ink jet part20in the X direction. Therefore, when moving while maintaining a gap that does not interfere with two ink jet parts20held by first supporting member45and two ink jet parts20held by second supporting member46of four ink jet parts20, a distance between the center of ink jet part20positioned at the left end and the center of ink jet part20positioned at the right end is A2.

As a result, it becomes A2<A1.

That is, the gap between ink jet part20attached to first X-axis linear motion mechanism11aand ink jet part20attached to second X-axis linear motion mechanism11bcan be set small. As a result, the entire length of printing apparatus1in the X direction can be reduced.

Hereinafter, a schematic configuration of printing apparatus1of Exemplary Embodiment 7 of the present disclosure will be described based onFIG. 21.

FIG. 21is a side view illustrating a schematic configuration of printing apparatus1according to Exemplary Embodiment 7. Hereinafter, the same parts as those in Exemplary Embodiment 1 are designated by the same reference numerals, and only the differences will be described.

As illustrated inFIG. 21, printing unit10of printing apparatus1of Exemplary Embodiment 7 includes X-axis linear motion mechanism11and a plurality of ink jet parts20.

Workpiece drive unit30includes drive mechanisms of five axes. Two axes among the drive mechanisms of five axes are Y-axis linear motion mechanism31and Z-axis linear motion mechanism32. The other three axes among the drive mechanisms of five axes are A-axis rotation mechanism35, B-axis rotation mechanism36, and C-axis rotation mechanism37.

C-axis rotation mechanism37is attached to Z-axis linear motion mechanism32via first arm61. C-axis rotation mechanism37rotates workpiece W with C-axis extending in the Z direction from first arm61as the center of rotation.

A-axis rotation mechanism35is attached to C-axis rotation mechanism37via second arm62. A-axis rotation mechanism35rotates workpiece W with A-axis extending in the X direction from second arm62as the center of rotation.

B-axis rotation mechanism36is attached to A-axis rotation mechanism35via an arm (not illustrated). Fixing jig40is attached to B-axis rotation mechanism36. B-axis rotation mechanism36rotates workpiece W with the B-axis extending in the Y direction as the center of rotation.

According to the configuration of Exemplary Embodiment 7, the number of drive mechanisms of workpiece drive unit30can be increased. As a result, the adjustment range of the position of workpiece W can be further widened.

Hereinafter, a schematic configuration of printing apparatus1of Exemplary Embodiment 8 of the present disclosure will be described based onFIG. 22.

FIG. 22is a side view illustrating a schematic configuration of printing apparatus1according to Exemplary Embodiment 8. Hereinafter, the same parts as those in Exemplary Embodiment 1 are designated by the same reference numerals, and only the differences will be described.

As illustrated inFIG. 22, printing unit10of printing apparatus1of Exemplary Embodiment 8 includes X-axis linear motion mechanism11and a plurality of ink jet parts20.

Workpiece drive unit30includes drive mechanisms of five axes. Two axes among the drive mechanisms of five axes are Y-axis linear motion mechanism31and Z-axis linear motion mechanism32. The other three axes among the drive mechanisms of five axes are A-axis rotation mechanism35, B-axis rotation mechanism36, and C-axis rotation mechanism37.

A-axis rotation mechanism35is attached to Z-axis linear motion mechanism32. A-axis rotation mechanism35rotates workpiece W with the A-axis extending in the X direction from Z-axis linear motion mechanism32as the center of rotation.

B-axis rotation mechanism36is attached to A-axis rotation mechanism35via box-shaped holding body42in which an upper side is opened. B-axis rotation mechanism36rotates workpiece W with the B-axis extending in the Y direction from A-axis rotation mechanism35as the center of rotation. Holding body42is formed in a box shape with an open upper portion, and houses supporting arm41, B-axis rotation mechanism36, and the like inside. Therefore, workpiece drive unit30can be made smaller.

C-axis rotation mechanism37is attached to B-axis rotation mechanism36via supporting arm41. Fixing jig40is attached to the front end side of C-axis rotation mechanism37. C-axis rotation mechanism37rotates workpiece W with C-axis extending in the Z direction from supporting arm41as the center of rotation.

According to the configuration of Exemplary Embodiment 8, the number of drive mechanisms of workpiece drive unit30can be increased. As a result, the adjustment range of the position of workpiece W can be further widened.

Hereinafter, a schematic configuration of printing apparatus1of Exemplary Embodiment 9 of the present disclosure will be described based onFIG. 23.

FIG. 23is a side view illustrating a schematic configuration of printing apparatus1according to Exemplary Embodiment 9. Hereinafter, the same parts as those in Exemplary Embodiment 1 are designated by the same reference numerals, and only the differences will be described.

As illustrated inFIG. 23, printing unit10of printing apparatus1of Exemplary Embodiment 9 includes X-axis linear motion mechanism11and a plurality of ink jet parts20.

Workpiece drive unit30includes drive mechanisms of five axes. Two axes among the drive mechanisms of five axes are Y-axis linear motion mechanism31and Z-axis linear motion mechanism32. The other three axes among the drive mechanisms of five axes are A-axis rotation mechanism35, B-axis rotation mechanism36, and C-axis rotation mechanism37.

A-axis rotation mechanism35is attached to Z-axis linear motion mechanism32. A-axis rotation mechanism35rotates workpiece W with the A-axis extending in the X direction from Z-axis linear motion mechanism32as the center of rotation.

B-axis rotation mechanism36is attached to A-axis rotation mechanism35via first arm61. B-axis rotation mechanism36rotates workpiece W with the B-axis extending in the Y direction from first arm61as the center of rotation.

C-axis rotation mechanism37is attached to B-axis rotation mechanism36via second arm62. Fixing jig40is attached to C-axis rotation mechanism37. C-axis rotation mechanism37rotates workpiece W with C-axis extending in the Z direction from second arm62as the center of rotation.

According to the configuration of Exemplary Embodiment 9, the number of drive mechanisms of workpiece drive unit30can be increased. As a result, the adjustment range of the position of workpiece W can be further widened.

Hereinafter, a schematic configuration of printing apparatus1of Exemplary Embodiment 10 of the present disclosure will be described based onFIG. 24.

FIG. 24is a side view illustrating a schematic configuration of printing apparatus1according to Exemplary Embodiment 10. Hereinafter, the same parts as those in Exemplary Embodiment 1 are designated by the same reference numerals, and only the differences will be described.

As illustrated inFIG. 24, printing unit10of printing apparatus1of Exemplary Embodiment 10 includes X-axis linear motion mechanism11and a plurality of ink jet parts20.

Workpiece drive unit30includes drive mechanisms of five axes. Two axes among the drive mechanisms of five axes are Y-axis linear motion mechanism31and Z-axis linear motion mechanism32. The other three axes among the drive mechanisms of five axes are A-axis rotation mechanism35, B-axis rotation mechanism36, and C-axis rotation mechanism37.

Y-axis linear motion mechanism31is mounted on frame2. Y-axis linear motion mechanism31moves workpiece W in the sub scanning direction.

C-axis rotation mechanism37is attached to Y-axis linear motion mechanism31. C-axis rotation mechanism37rotates workpiece W with C-axis extending in the Z direction from Y-axis linear motion mechanism31as the center of rotation.

Z-axis linear motion mechanism32is attached to C-axis rotation mechanism37. Z-axis linear motion mechanism32moves workpiece W in the vertical direction.

A-axis rotation mechanism35is attached to Z-axis linear motion mechanism32. A-axis rotation mechanism35rotates workpiece W with the A-axis extending in the X direction from Z-axis linear motion mechanism32as the center of rotation.

B-axis rotation mechanism36is attached to A-axis rotation mechanism35via first arm61. Fixing jig40is attached to B-axis rotation mechanism36via second arm62. B-axis rotation mechanism36rotates workpiece W with the B-axis extending in the Y direction from first arm61as the center of rotation.

According to the configuration of Exemplary Embodiment 10, the number of drive mechanisms of workpiece drive unit30can be increased. As a result, the adjustment range of the position of workpiece W can be further widened.