TWI852123B - Transport apparatus, liquid-drop ejecting apparatus and transport method - Google Patents

Abstract

The present invention provides a technology that can detect deformations such as wrinkles generated by a continuous substrate during conveyance with high sensitivity. A printing device (1) comprises: a plurality of conveyance rollers (12), a pattern light irradiation unit (30), a photographing device (40) and a height information acquisition unit (53). The pattern light irradiation unit (30) irradiates the surface of a continuous substrate (9) conveyed by a plurality of conveyance rollers (12) with pattern light (31). The photographing device (40) photographs a grid pattern (33) formed on the continuous substrate (9) by irradiation with the pattern light (31). The height information acquisition unit (53) acquires height information corresponding to the height of the continuous substrate (9) based on the positions of a plurality of intersections (35) of the grid pattern (33) in the image photographed by the photographing device (40).

Description

Transport device, droplet discharge device, and transport method

The present invention relates to a transport device, a liquid droplet ejection device and a transport method.

It is known that there is a device that uses rollers to transport a continuous substrate (roll) while printing or performing a predetermined process on the continuous substrate. For example, Patent Document 1 discloses a technology that can prevent wrinkles from forming on a roll when the roll is transported. Specifically, in an image obtained by photographing a roll (10) using a photographing device (3), a wavy straight line (L) that is a precursor of wrinkles is detected. Furthermore, according to the relationship between the composite surface roughness σ of the free roller (2c) or the driving roller (2d) and the web and the floating amount h of the web (10) relative to the rollers (2), the direction of the axis (20c) of the free roller (2c) or the axis (20d) of the driving roller (2d) is adjusted for the waveform line (L) that is a precursor to the generation of wrinkles. [Prior technical literature] [Patent literature]

Patent document 1: Japanese Patent Publication No. 2010-195558

However, in the conventional technology, the waveform on the surface of the roll material that is a precursor of wrinkles is directly detected on the image photographed by a camera. Therefore, it is difficult to detect very small waveforms. In addition, when light cannot properly illuminate the waveform, it is not easy to detect the waveform on the image. Therefore, a technology that can detect deformations such as wrinkles of a continuous substrate with high sensitivity is needed.

The purpose of the present invention is to provide a technology that can detect deformations such as wrinkles of a continuous substrate during transportation with high sensitivity.

In order to solve the above problems, the first aspect of the present invention is a conveying device, which is a conveying device for conveying a long strip-shaped continuous substrate, and is equipped with: a plurality of rollers, which convey the continuous substrate; a pattern light irradiation unit, which irradiates the surface of the continuous substrate conveyed by the plurality of rollers with pattern light; a photographing device, which photographs the prescribed pattern formed on the continuous substrate by irradiating the pattern light; and a height information acquisition unit, which acquires height information corresponding to the height of the continuous substrate according to the positions of the plurality of points of the prescribed pattern in the image photographed by the photographing device.

The second aspect of the present invention is that in the conveying device of the first aspect, the calculation unit calculates the center of gravity of the above-mentioned multiple points as the above-mentioned height information.

The third aspect of the present invention is that in the conveying device of the first aspect or the second aspect, the above-mentioned prescribed pattern includes a plurality of first straight lines parallel to each other, and a plurality of second straight lines intersecting the plurality of first straight lines.

The fourth aspect of the present invention is that in the conveying device of the third aspect, the second straight line is orthogonal to the first straight line.

The fifth aspect of the present invention is that in any one of the conveying devices of the first to fourth aspects, there is further provided with a skew correction unit for correcting the skew of the image photographed by the above-mentioned photographing device; the above-mentioned height information acquisition unit obtains the above-mentioned height information based on the image processed by the above-mentioned skew correction unit.

The sixth aspect of the present invention is a conveying device in any one of the first to fifth aspects, further comprising: a roller moving unit that moves at least one roller among the plurality of rollers; and a roller moving control unit that controls the roller moving unit based on the height information.

A seventh aspect of the present invention is a liquid droplet discharge device comprising: the transport device of any one of the first to sixth aspects; and a discharge unit that discharges liquid droplets toward the continuous substrate transported by the transport device.

The eighth aspect of the present invention is a method for conveying a continuous substrate in the form of a long strip, which comprises the following steps: a) conveying the continuous substrate by a plurality of rollers; b) irradiating the surface of the continuous substrate conveyed by the step a) with pattern light; c) photographing the prescribed pattern formed on the continuous substrate by the step b) by a photographing device; and d) obtaining height information corresponding to the height of the continuous substrate based on the positions of a plurality of points of the prescribed pattern in the image obtained by the step c).

According to the conveying device of the first to sixth aspects of the present invention, the grid pattern formed on the continuous substrate is deformed according to the surface height of the continuous substrate. Therefore, by the position of multiple points of the specific grid pattern, it is possible to obtain height information corresponding to the surface height of the continuous substrate. In addition, since the grid pattern is formed on the surface of the continuous substrate by irradiation with pattern light, it is possible to obtain a clearer image of the grid pattern. Thereby, even if the image photographed by the self-photographic device is deformed and difficult to directly identify, it can be detected with high sensitivity by the position of multiple points of the specific grid pattern.

According to the second aspect of the conveying device of the present invention, by detecting the change of the center of gravity of a plurality of points in the above-mentioned pattern light irradiated on the continuous substrate, it can detect the change of the height of the continuous substrate.

According to the conveying device of the third aspect of the present invention, by making the first straight line intersect with the second straight line, a plurality of intersections that are easy to identify can be formed.

According to the conveying device of the fifth aspect of the present invention, by correcting the skewness of the image, it is possible to appropriately obtain height information.

According to the conveying device of the sixth aspect of the present invention, by moving the roller according to the height position, it is possible to correct the variation of the surface height of the continuous substrate, thereby correcting deformation such as wrinkles.

According to the seventh aspect of the present invention, the droplet ejection device can detect changes in the surface height of wrinkles, etc., so it can suppress the reduction in process quality caused by the generation of wrinkles, etc.

According to the conveying method of the eighth aspect of the present invention, the grid pattern formed on the continuous substrate can be deformed in response to the surface height of the continuous substrate. Therefore, by the position of multiple points of the specific grid pattern, it is possible to obtain height information corresponding to the surface height of the continuous substrate. In addition, since the grid pattern is formed on the surface of the continuous substrate by irradiation with pattern light, it is possible to obtain a clearer image of the grid pattern. In this way, even if it is difficult to directly recognize the deformation from the image photographed by the camera, it can be detected with high sensitivity by the position of multiple points of the specific grid pattern.

Hereinafter, the embodiments of the present invention will be described with reference to the attached drawings. Furthermore, the components described in the embodiments are merely exemplary and do not mean that the scope of the present invention is limited thereto. In the attached drawings, the size and quantity of each part may be exaggerated or simplified as necessary for ease of understanding.

＜1. Implementation form＞

FIG. 1 is a diagram showing the overall structure of a printing device 1 of the present embodiment. The printing device 1 is an inkjet printing device, which is configured to transport a long strip of continuous substrate 9 while ejecting ink droplets (hereinafter referred to as "ink droplets") from a plurality of nozzles (a first nozzle 21, a second nozzle 22, a third nozzle 23, and a fourth nozzle 24) toward the continuous substrate 9, thereby printing an image on the surface of the continuous substrate 9. The printing device 1 is an example of a droplet ejection device. The continuous substrate 9 is, for example, printing paper, a resin film, a metal foil, or a glass substrate. As shown in FIG. 1, the printing device 1 has a transport mechanism 10, a printing unit 20, a pattern light irradiation unit 30, a photographing device 40, and a control unit 50.

The conveying mechanism 10 is an example of a conveying device. The conveying mechanism 10 is configured to convey the continuous substrate 9 in a conveying direction along the length direction. The conveying mechanism 10 has a roll-out portion 11, a plurality of conveying rollers 12, and a take-up portion 13. The roll-out portion 11 is configured to rotatably hold the continuous substrate 9 in a roll shape while continuously feeding out the continuous substrate 9. Each conveying roller 12 is configured to rotate around an axis extending in a direction perpendicular to the conveying direction. Each conveying roller 12 guides the continuous substrate 9 continuously fed out from the roll-out portion 11 toward the take-up portion 13 on the downstream side of the conveying path. The winding section 13 is configured to wind up the continuous substrate 9 continuously fed from the unwinding section 11 in a roll shape. The continuous substrate 9 is hung on a plurality of conveying rollers 12 under a tension applied thereto. Thus, the slack and wrinkles of the continuous substrate 9 during the conveying process are suppressed to a certain extent.

In this specification, the width direction orthogonal to the length direction (conveying direction) of the continuous substrate 9 conveyed by the conveying mechanism 10 is referred to as the "width direction". In addition, the direction perpendicular to the surface of the continuous substrate 9 is referred to as the "up-down direction". The conveying mechanism 10 conveys the continuous substrate 9 with the surface of the continuous substrate 9, i.e., the printing surface, facing upward.

The printing unit 20 discharges ink droplets to the continuous substrate 9 conveyed by the conveying mechanism 10. The printing unit 20 has four nozzles (a first nozzle 21, a second nozzle 22, a third nozzle 23, and a fourth nozzle 24). The four first nozzles 21 to the fourth nozzles 24 are arranged at equal intervals along the conveying direction of the continuous substrate 9. The continuous substrate 9 is arranged at a position separated from the first nozzle unit 21 to the fourth nozzle unit 24 below. The printing surface of the continuous substrate 9 is opposite to the bottom surface of the first nozzle 21 to the fourth nozzle 24.

FIG2 is a partial top view showing the printing unit 20 and its periphery in the printing device 1. In FIG2, as indicated by the dotted lines, a plurality of nozzles 201 are arranged below the first to fourth nozzles 21 to 24 in parallel with the width direction of the continuous substrate 9. The first to fourth nozzles 21 to 24 are configured to eject inks of K (black), C (cyan), M (magenta), and Y (yellow) from the plurality of nozzles 201 toward the printing surface of the continuous substrate 9.

The first nozzle 21 ejects K color ink droplets toward the continuous substrate 9 at the first printing position P1 on the conveying path. The second nozzle 22 ejects C color ink droplets toward the printing surface of the continuous substrate 9 at the second printing position P2 downstream of the first printing position P1 in the conveying direction. The third nozzle 23 ejects M color ink droplets toward the printing surface of the continuous substrate 9 at the third printing position P3 downstream of the second printing position P2 in the conveying direction. The fourth nozzle 24 ejects Y color ink droplets toward the printing surface of the continuous substrate 9 at the fourth printing position P4 downstream of the third printing position P3 in the conveying direction.

The printing device 1 may also be provided with a drying unit on the downstream side of the conveying direction of the first to fourth nozzles 21 to 24, and the drying unit is used to dry the ink droplets supplied to the printing surface of the continuous substrate 9 (more specifically, to vaporize the solvent in the ink droplets). The drying unit is configured, for example, to blow gas heated by a heater or the like toward the continuous substrate 9. In addition, the drying unit may also be configured to dry or harden the ink droplets by infrared irradiation or light irradiation.

At least one of the plurality of conveying rollers 12 is provided with an encoder 14. The encoder 14 detects the rotation amount of the conveying roller 12. Specifically, whenever the conveying roller 12 rotates by a predetermined angle, the encoder 14 outputs a pulse signal to the control unit 50. The control unit 50 obtains the conveying amount of the continuous substrate 9 according to the pulse signal of the encoder 14. Furthermore, the control unit 50 determines the timing of the first to fourth nozzles 21 to 24 to eject ink according to the conveying amount. In addition, the encoder 14 can also detect the rotation amount of a roller different from the conveying roller 12.

<Pattern light irradiation section> As shown in FIG1 , the pattern light irradiation section 30 is arranged on the upstream side of the printing section 20 in the conveying direction. As shown in FIG1 , the pattern light irradiation section 30 is arranged at a position separated from the continuous substrate 9 on the upper side.

Fig. 3 is a perspective view showing the pattern light irradiation unit 30. As shown in Fig. 3, the pattern light irradiation unit 30 irradiates the surface of the continuous substrate 9 with pattern light 31 of a predetermined shape. As shown in Fig. 1 and Fig. 3, the pattern light irradiation unit 30 irradiates the surface of the continuous substrate 9 between two conveying rollers 12, 12 adjacent to each other in the conveying direction with the pattern light 31.

The pattern light 31 irradiated onto the surface of the continuous substrate 9 forms a grid pattern 33 of a predetermined shape on the continuous substrate 9. The grid pattern 33 has a plurality of first straight lines 331 parallel to each other and a plurality of second straight lines 332 parallel to each other. The plurality of first straight lines 331 and the plurality of second straight lines 332 are formed by reflection of the linear light of the pattern light 31 on the surface of the continuous substrate 9. The first straight lines 331 and the second straight lines 332 intersect each other, and are preferably orthogonal to each other. The first straight lines 331 are preferably parallel to the conveying direction, and the second straight lines 332 are preferably parallel to the width direction.

Furthermore, the pattern formed on the continuous substrate 9 by the pattern light irradiation unit 30 is not limited to the grid pattern 33, and may be any pattern as long as the positions of a plurality of points can be specified.

In addition, in this example, although the pattern light 31 is made incident on the surface of the continuous substrate 9 vertically, the pattern light 31 may also be made incident on the continuous substrate 9 obliquely.

<Photographic device> The photographic device 40 photographs the surface of the continuous substrate 9 irradiated with the pattern light 31. The photographic device 40 is arranged downstream of the pattern light irradiation unit 30 in the conveying direction. The photographic device 40 has an image sensor such as a CCD (charge-coupled device) or a CMOS (complementary metal oxide semiconductor). The photographic device 40 is connected to the control unit 50 in a communicable manner. The photographic device 40 transmits a signal showing the image photographed by the image sensor to the control unit 50.

The photographing device 40 has a lens (not shown). As shown in FIG3 , the optical axis 41 of the lens is inclined obliquely relative to the surface of the continuous substrate 9. The optical axis 41 is oriented toward the center of the pattern light 31.

Furthermore, the orientation and posture of the pattern light irradiation unit 30 and the camera device 40 can also be appropriately changed according to the structure of the conveying mechanism 10 or the printing device 1. For example, in the example shown in FIG. 3, the camera device 40 is arranged on the downstream side of the conveying direction relative to the pattern light irradiation unit 30. However, the camera device 40 can also be arranged on the upstream side of the conveying direction relative to the pattern light irradiation unit 30. In addition, the camera device 40 can also be arranged on the side in the width direction relative to the pattern light irradiation unit 30. Moreover, the pattern light irradiation unit 30 and the camera device 40 can also be arranged not on the printing surface side of the continuous substrate 9, but on the opposite side (back side).

As shown in FIG3 , the conveying mechanism 10 includes a roller moving portion 15. The roller moving portion 15 moves one of the conveying rollers 12. In the following description, the conveying roller 12 moved by the roller moving portion 15 is also referred to as a "movable conveying roller". In addition, the so-called "moving the movable conveying roller" includes the case where the movable conveying roller is moved parallel to the movable conveying roller and the case where the movable conveying roller is moved in a tilted manner relative to the rotation axis.

As shown in FIG3 , the roller moving section 15 is connected to the roller shaft 121 of the movable conveying roller. The roller moving section 15 moves the movable conveying roller according to the change instruction output by the control section 50 (specifically, the roller movement control section 55). In addition, the roller moving section 15 may be configured to move not only a single conveying roller 12 but also a plurality of conveying rollers 12.

FIG. 4 schematically shows the movement of the movable conveying roller by the roller moving unit 15. As shown in FIG. 4(a), the roller moving unit 15 can move the movable conveying roller parallel to the conveying direction and the height direction. In addition, as shown in FIG. 4(b), the roller moving unit 15 can move the movable conveying roller parallel to the width direction. In addition, as shown in FIG. 4(c) and (d), the roller moving unit 15 can move the movable conveying roller obliquely in the height direction or the conveying direction.

Furthermore, the roller moving part 15 can also be configured to perform only any one of the parallel movement or the tilting movement in each movement shown in Figure 4. In addition, the roller moving part 15 can also be configured to move the conveying roller 12 toward only a part of the direction in the conveying direction, the height direction, and the width direction.

As shown in FIG3 , the continuous substrate 9 is wound around the movable conveying roller at a predetermined winding angle. That is, the movable conveying roller applies tension to the continuous substrate 9. Therefore, the roller moving unit 15 adjusts the magnitude or direction of the tension on the continuous substrate 9 by moving the movable conveying roller.

3, the movable conveyor roller is a conveyor roller 12 disposed downstream of the position (irradiation position) where the continuous substrate 9 is irradiated with the pattern light 31. However, the movable conveyor roller may be a conveyor roller 12 disposed upstream of the irradiation position.

FIG5 is a block diagram schematically showing the connection between the control unit 50 and each part of the printing device 1. The control unit 50 is an information processing device, and is configured to control the operation of each part of the printing device 1. As shown in FIG3, the control unit 50 is configured by a computer, and the computer has a processor 501 such as a CPU, a memory 502 such as a RAM, and a storage unit 503 such as a hard disk drive. The storage unit 503 stores a computer program 80 for controlling the operation of each part of the printing device 1.

As shown in FIG5 , the control unit 50 is connected to the conveying mechanism 10, the first nozzle 21 to the fourth nozzle 24, the pattern light irradiation unit 30, the imaging device 40, and the roller moving unit 15 in a communicable manner. The control unit 50 controls the conveying mechanism 10 and the first nozzle 21 to the fourth nozzle 24 according to the computer program 80. The control unit 50 controls the roller moving unit 15 of the conveying mechanism 10 according to the computer program 80.

FIG6 is a block diagram conceptually showing the functional structure of the control unit 50. As shown in FIG6, the control unit 50 includes a skew correction unit 51, a height information acquisition unit 53, a roller movement control unit 55, and a discharge control unit 57. The skew correction unit 51, the height information acquisition unit 53, the roller movement control unit 55, and the discharge control unit 57 are functions implemented by the processor 501 executing the computer program 80. In addition, part or all of the functions of the control unit 50 may also be implemented by a dedicated circuit.

The skew correction unit 51 performs a process for correcting the skew of the image acquired by the photographing device 40 (hereinafter, also referred to as "skew correction process"). The height information acquisition unit 53 acquires height information corresponding to the height of the surface of the continuous substrate 9 (the position of the surface of the continuous substrate 9 in the vertical direction) based on the corrected image whose skew is corrected. Hereinafter, the surface height of the continuous substrate 9 is also referred to as "surface height". The roller movement control unit 55 controls the roller movement unit 15 based on the height information acquired by the height information acquisition unit 53.

The ejection control unit 57 controls the first to fourth ejection heads 21 to 24. Specifically, the ejection control unit 57 outputs a printing instruction to the first to fourth ejection heads 21 to 24 based on the conveyance amount of the continuous substrate 9 based on the output from the encoder 14 and the image data to be printed. The first to fourth ejection heads 21 to 24 eject ink droplets from the nozzles 201 specified in the printing instruction at the timing specified in the printing instruction.

<Operation of the printing device> FIG. 7 is a flowchart showing the operation of the printing device 1. Unless otherwise specified, each process shown in FIG. 7 is performed under the control of the control unit 50. In addition, in steps S11 to S18 shown in FIG. 7, steps S11 to S15 are processes for detecting the change in the surface height of the continuous substrate 9, and step S16 is a process for correcting the change in the surface height.

If a part of the continuous substrate 9 is deformed such as wrinkles, the surface height of the deformed part changes from the surface height serving as a reference (hereinafter, also referred to as "reference height"). Therefore, in steps S11 to S15, the deformation such as wrinkles of the continuous substrate 9 is detected by detecting the change in the surface height. In addition, in step S16, the movable conveying roller is moved to eliminate the deformation such as wrinkles generated in the continuous substrate 9.

Furthermore, before starting step S11 shown in FIG. 7 , the conveying mechanism 10 starts conveying the continuous substrate 9 , and as shown in FIG. 3 , the pattern light 31 is irradiated onto the continuous substrate 9 .

First, the control unit 50 obtains an image of the grid pattern 33 on the surface of the continuous substrate 9 photographed by the photographing device 40 (step S11). Then, the skew correction unit 51 of the control unit 50 performs skew correction processing on the image obtained in step S11 (step S12).

FIG8 is a conceptual diagram showing the skew correction process. The original image 81 shown in FIG8 is an initial image obtained by the photographing device 40. As shown in FIG8, according to the photographing conditions of the grid pattern 33 by the photographing device 40 (for example, the positional relationship between the photographing device 40 and the grid pattern 33, the type of lens of the photographing device 40, etc.), the grid pattern 33 may be skewed. In the example shown in FIG8, the plurality of first straight lines 331 constituting the grid pattern 33 are not parallel to each other. In addition, the intervals between adjacent second straight lines 332 are not constant.

The skew correction unit 51 extracts, for example, a portion of the plurality of first straight lines 331 and a portion of the plurality of second straight lines 332 in order to correct the skew of the grid pattern 33. In the example shown in FIG8 , the skew correction unit 51 extracts every other first straight line 331 and every other second straight line 332. Hereinafter, the extracted lines are referred to as "extracted lines".

The skew correction unit 51 corrects the original image 81 in such a manner that the extracted lines of the first straight line 331 are parallel to each other and the extracted lines of the second straight line 332 are parallel to each other. In addition, the skew correction unit 51 corrects the original image 81 in such a manner that the first straight line 331 and the second straight line 332 are orthogonal to each other. The skew correction unit 51 generates a corrected image 83 from the original image 81 through such skew correction processing. As shown in FIG8 , in the corrected image 83, a plurality of first straight lines 331 are corrected to be parallel to each other, and a plurality of second straight lines 332 are also corrected to be parallel to each other. Furthermore, a plurality of first straight lines 331 are corrected to be orthogonal to a plurality of second straight lines 332. In this way, the skew of the original image 81 can be removed through the skew correction processing of the skew correction unit 51.

As shown in FIG. 7 , after step S12, the height information acquisition unit 53 of the control unit 50 acquires the positions of a plurality of intersections included in the grid pattern 33 in the corrected image 83 generated in step S12 (step S13). Then, the height information acquisition unit 53 calculates the position of the center of gravity based on the acquired positions of the intersections (step S14).

As shown in FIG8 , the height information acquisition unit 53 acquires the positions of each intersection 35 (grid point) where a plurality of first straight lines 331 and a plurality of second straight lines 332 intersect on the corrected image 83 in step S13. Then, the height information acquisition unit 53 calculates the position of the centroid 37 of the four intersections 35 of each unit grid. The unit grid is the smallest unit of the grid pattern 33 and is defined by two mutually adjacent first straight lines 331 and two mutually adjacent second straight lines 332.

FIG9 is a graph showing the temporal change of the position of a specific center of gravity 37 (curve G11) and the temporal change of the surface height of the portion corresponding to the specific center of gravity 37 (curve G21). In FIG9, the horizontal axis shows time. The vertical axis of curve G11 shows the position (pixel) on the image, and the vertical axis of curve G21 shows the surface height (μm) of the continuous substrate 9. The height of the continuous substrate 9 is a value measured by a displacement sensor (ultrasonic displacement sensor or optical interference displacement sensor, etc.).

As shown in FIG. 9 , if the height of the continuous substrate 9 changes, the position of the center of gravity 37 on the image also changes. In particular, when the height of the continuous substrate 9 changes from the reference value (0), the position of the center of gravity 37 also changes accordingly. In addition, the magnitude of the position change of the center of gravity 37 is roughly proportional to the magnitude of the change of the height measured value (G11). In this way, the position of the center of gravity 37 is the height information corresponding to the surface height of the continuous substrate 9. Therefore, the height information acquisition unit 53 acquires the position of each center of gravity 37 as the height information in step S14.

As shown in FIG. 7 , if the height information is obtained in step S14, the control unit 50 determines whether deformation occurs based on the height information, i.e., the position of each center of gravity 37 (step S15). Specifically, the deformation of the continuous substrate 9 is determined based on the size of the change of each center of gravity 37 relative to the reference height, and the width or shape of the range in which the center of gravity 37 changes. For example, when a wrinkle (trough) extending in a linear shape occurs, the displacement of the center of gravity 37 occurs along the line. Therefore, for example, by determining whether the range in which the center of gravity 37 changes is linear, the generation of linear wrinkles can be detected.

In step S15, when it is determined that deformation has occurred, the roller movement control unit 55 of the control unit 50 moves the movable conveying roller in such a manner that the position of each center of gravity 37 becomes a reference height (step S16). In step S15, when it is determined that deformation has not occurred, the control unit 50 skips the processing of step S16 and proceeds to step S17.

After step S16, the control unit 50 determines whether the conveyance of the continuous substrate 9 by the conveying mechanism 10 is stopped (step S17). For example, the control unit 50 may determine that the conveyance is stopped when the printing process is completed. In step S17, when the control unit 50 determines that the conveyance of the continuous substrate 9 is stopped, the control unit 50 stops the conveyance of the continuous substrate 9 by controlling the conveying mechanism 10 (step S18). On the other hand, in step S17, when it is determined that the conveyance of the continuous substrate 9 is not stopped, the control unit 50 returns to step S11 and continues the process.

<Effect> The grid pattern 33 formed by the continuous substrate 9 is deformed in response to the surface height of the continuous substrate 9. Therefore, by specifying the positions of multiple points of the grid pattern 33, it is possible to obtain height information corresponding to the surface height of the continuous substrate 9.

In addition, since the grid pattern 33 is formed on the surface of the continuous substrate 9 by irradiation with the pattern light 31, the image of the grid pattern 33 can be obtained more clearly. Therefore, even if the image photographed by the self-photographing device 40 is deformed and difficult to directly recognize, it can be detected with high sensitivity by specifying the positions of multiple points of the grid pattern 33.

Furthermore, by moving the movable conveying roller, the variation of the surface height of the continuous substrate 9 is corrected, so that the deformation of the continuous substrate 9 is corrected. Thereby, it is possible to suppress the occurrence of traces such as folds on the continuous substrate 9 due to the deformation.

Furthermore, by arranging the movable conveying roller upstream of the printing section 20, it is possible to correct the deformation of the continuous substrate 9 before the printing section 20 starts printing. Therefore, it is possible to suppress the position of the image printed on the continuous substrate 9 by the printing section 20 from being shifted due to the deformation of the continuous substrate 9. Therefore, it is possible to suppress the deterioration of the quality of the printing process.

<2. Variations> Although the present embodiment has been described above, the present invention is not limited to the above embodiment, and various variations are possible.

In the above-mentioned embodiment, the height information acquisition unit 53 acquires the position of the center of gravity 37 as the height information. However, the height information is not limited to the position of the center of gravity 37. For example, the height information acquisition unit 53 can also calculate the surface height of the continuous substrate 9 from the position of each intersection 35 of the grid pattern 33 by triangulation based on the relationship between the irradiation direction of the pattern light 31 and the direction when observed by the camera 40.

In the above-mentioned embodiment, the roller movement control unit 55 suppresses the deviation of the printing position by correcting the surface height of the continuous substrate 9 according to the height information. It can also be replaced by the ejection control unit 57 correcting the printing instruction supplied to the printing unit 20 according to the height information, thereby suppressing the deviation of the printing position. For example, when the surface height of a specific part of the continuous substrate 9 is higher than the reference height, the flight time of the ink droplets (the time from the time the ink droplets are ejected from the nozzle 201 to the time they land on the continuous substrate 9) is shortened compared to the usual one. In this case, the printing instruction can be corrected in a manner that the ejection timing is delayed in response to the surface height. In addition, when the surface height of the continuous substrate 9 is lower than the reference height, the flight time can be extended. In this case, the printing instruction can be corrected in a manner that the ejection timing is advanced. In this way, the ejection control unit 57 can correct the printing instruction according to the height information, thereby suppressing the reduction of the printing process quality. Furthermore, the movement of the movable conveying roller by the roller movement control unit 55 and the correction of the printing instruction by the ejection control unit 57 can also be implemented in combination.

Although the present invention has been described in detail above, the above description is only illustrative for all aspects, and the present invention is not limited thereto. It should be understood that as long as it does not exceed the scope of the essential content of the present invention, it is possible to imagine countless variations that are not exemplified. The various structures described in the above embodiments and variations can be appropriately combined or omitted as long as they do not contradict each other.

1: Printing device 9: Continuous substrate 10: Transport mechanism 11: Unwinding section 12: Transport roller 13: Unwinding section 14: Encoder 15: Roller moving section 20: Printing section 21: First nozzle (discharging section) 22: Second nozzle 23: Third nozzle 24: Fourth nozzle 30: Pattern light irradiation section 31: Pattern light 33: Grid pattern 35: Intersection point 37: Center of gravity 40: Photographic device 41: Optical axis 50: Control section 51: Skew correction section 53: Height information acquisition section 55: Roller moving control section 57: Discharging control section 80: Computer program 81: Original image 83: Corrected image 121: Roller 201: Nozzle 331: First straight line 332: Second straight line 501: Processor 502: Memory 503: Memory unit P1: First printing position P2: Second printing position P3: Third printing position P4: Fourth printing position

FIG. 1 is a diagram showing the overall structure of the printing device of the present embodiment. FIG. 2 is a partial top view showing the printing section and its periphery in the printing device. FIG. 3 is a three-dimensional diagram showing the pattern light irradiation section. FIG. 4 (a) to (d) are diagrams schematically showing the movement of the movable conveying roller by the roller moving section. FIG. 5 is a block diagram schematically showing the connection between the control section and each part of the printing device. FIG. 6 is a block diagram conceptually showing the functional structure of the control section. FIG. 7 is a flow chart showing the operation of the printing device. FIG. 8 is a diagram conceptually showing the skew correction process. FIG. 9 is a diagram showing the change of the position of a specific center of gravity over time and the change of the surface height of the portion corresponding to the specific center of gravity over time.

9: Continuous substrate

12: Transport roller

15: Roller moving part

30: Pattern light irradiation part

31: Pattern light

33: Grid pattern

40:Photographic equipment

41: Light axis

50: Control Department

121: Roller

331: The first straight line

332: Second straight line

Claims (7)

A conveying device is a conveying device for conveying a long strip-shaped continuous substrate; it has: a plurality of rollers for conveying the continuous substrate; a pattern light irradiation unit for irradiating the surface of the continuous substrate conveyed by the plurality of rollers with pattern light; a photographing device for photographing a predetermined pattern formed on the continuous substrate by irradiation with the pattern light; and a height information acquisition unit for acquiring height information corresponding to the height of the continuous substrate based on the positions of the plurality of points of the predetermined pattern in the image photographed by the photographing device; the height information acquisition unit calculates the center of gravity of the plurality of points as the height information. As in claim 1, the conveying device, wherein the prescribed pattern includes a plurality of first straight lines parallel to each other, and a plurality of second straight lines intersecting the plurality of first straight lines. As in claim 2, the conveying device, wherein the second straight line is orthogonal to the first straight line. The conveying device as claimed in claim 1 or 2, further comprising: a skew correction unit for correcting the skew of the image photographed by the photographing device; and the height information acquisition unit for acquiring the height information based on the image processed by the skew correction unit. The conveying device as claimed in claim 1 or 2, further comprising: a roller moving unit that moves at least one of the plurality of rollers; and a roller moving control unit that controls the roller moving unit based on the height information. A liquid droplet discharge device, comprising: a conveying device according to any one of claims 1 to 5; and a discharge unit that discharges liquid droplets toward the continuous substrate conveyed by the conveying device. A method for conveying a long strip-shaped continuous substrate, comprising the following steps: a) conveying the continuous substrate using a plurality of rollers; b) irradiating the surface of the continuous substrate conveyed in the step a) with pattern light; c) photographing the prescribed pattern formed on the continuous substrate in the step b) using a photographing device; and d) obtaining height information corresponding to the height of the continuous substrate according to the positions of the plurality of points of the prescribed pattern in the image obtained in the step c); the step d) includes calculating the center of gravity of the plurality of points as the height information.