JP2021133289A - Ink jet printing method and ink jet printer - Google Patents

Abstract

To provide an ink jet printing method which determines rotation amount of an optimum head without performing test printing at each time even if pitch of a coating target portion of a coating object is changed and accurately combines impact pitch of droplet with the pitch of the coating target portion.SOLUTION: An ink jet printing method includes: a first process which reads data related to an impact position deviation characteristic from storage means 110 for storing the impact position deviation characteristic determined on the basis of an impact position deviation from a target position of droplet discharged from an ink jet head 8 when the ink jet head 8 is at first and second rotation angles which are different from each other, respectively; and a second process which determines a target rotation angle of the ink jet head 8 on the basis of the impact position deviation characteristic, array pitch of a droplet discharge nozzle of the ink jet head 8, and coating target pitch of a coating object 1 in a direction orthogonal to a scanning direction and generates a printing pattern corresponding to the target rotation angle.SELECTED DRAWING: Figure 1

Description

The present invention relates to an inkjet printing apparatus and a printing method using the same, and particularly to a method of adjusting a coating pitch of an inkjet head.

In recent years, a method of manufacturing a device using an inkjet printing device has attracted attention. The inkjet printing device has a plurality of nozzles for ejecting droplets, and ejects droplets from the nozzles while controlling the positional relationship between the nozzles and the coating target portion of the printing object to achieve the coating target of the printing object. A droplet is applied to the portion. As a print target, there is one in which coating target portions of the print target are arranged at a constant pitch as typified by a display device.

In that case, the pitch of the landed droplets is set by rotating the inkjet head in which a plurality of nozzles are arranged at a constant pitch around the rotation axis in the normal direction of the surface of the object to be printed. A method of applying according to the pitch is disclosed. (For example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2001-108820

This conventional method will be described with reference to FIGS. 14 and 15. FIG. 14 is a diagram showing the positional relationship between the pitch of the coating target portion and the droplet ejection nozzle of the inkjet head, and FIG. 15 is the pitch of the conventional coating target portion and the impact of the droplets ejected from the inkjet head and landed on the substrate. It is a figure which shows the operation flow which adjusts a pitch.

In FIG. 14, 108 is an inkjet head, 117 is a droplet ejection nozzle of the inkjet head 108, 119 is a substrate, 101 is a coating target portion on the substrate 119, and 118 is a droplet landed on the coating target portion 101. ..

_{FIG. 14A shows a case where the pitch W 1} of the coating target portion 101 is equal to the pitch L of the droplet ejection nozzle 117, and FIG. 14B shows a case where the pitch W _{2 of the coating target portion 101 is equal to the pitch L of the droplet ejection nozzle 117.} It represents a case where the pitch L of the droplet ejection nozzle 117 is smaller than that.

In FIG. 14, the inkjet head 108 and the substrate 119 are configured to eject droplets from the droplet ejection nozzle 117 while relatively moving in the X direction in the drawing to apply the droplets to the coating target portion 101. .. Then, as shown in FIG. 14B, when the pitch W ₂ of the coating target portion 101 is smaller than the pitch L of the droplet ejection nozzle 117, the inkjet head 108 is rotated by θ to rotate the droplet ejection nozzle 117 in the Y direction. Can be adjusted to _{the pitch W 2} of the coating target portion 101.

In this conventional method, an operation of matching the pitch of the droplet 118 ejected from the droplet ejection nozzle 117 and landing on the substrate 119 in the Y direction with the pitch of the coating target portion 101 of the substrate 119 will be described with reference to FIG.

In FIG. 15, “drawing a pattern for adjustment” in S1 is a step of applying a test pattern for measuring a droplet pitch, and “inputting a drawn pattern by a sensor” in S2 is a step of capturing a test pattern with a camera or the like, in S3. The "dot cutting process" is a process of cutting out a droplet portion from the data captured in S2, and the "dot center of gravity calculation process" of S4 is a step of calculating the center of gravity of a droplet from the droplet data extracted in S3. "R pitch calculation, G pitch calculation, B pitch calculation" is a step of calculating the landing pitch of each landing droplet of R, G, B from the position of the center of gravity of each landing droplet of R, G, B obtained in S4, S6. "Calculation of pitch between RGs and pitch calculation between GBs" calculates the landing pitch between RGs and the landing pitch between GBs from the positions of the centers of gravity of the R landing droplets, G landing droplets, and B landing droplets extracted in S4. In step S7, "Is each RGB pitch at a predetermined distance?" Is a step of determining whether the landing pitch of each of the R, G, and B landing droplets calculated in S5 is the target distance, in S8. "Is the pitch between RGs and the pitch between GBs at a predetermined distance?" Is the step of determining whether or not the landing pitch between RGs and the landing pitch between GBs calculated in S6 is the target distance, "" in S9. "Adjusting the Y-axis of the drawing head" is a step of moving the drawing head in the Y direction to adjust the position when the RG landing pitch and the GB landing pitch are not at the target distance in S8, and the "drawing head" in S10. "Adjusting the θ-axis of" is a step of adjusting the θ-rotation of the drawing head when each RGB landing pitch does not reach the target distance in S7.

In this conventional method, the test pattern is printed in S1, the landing position of the droplet of the test pattern is detected in S2 to S4, the landing pitches of R, G, and B are calculated in S5, and the landing pitch is in S7. Is matched with the target value, and if not matched, the θ rotation of the head is adjusted in S10, and then the test printing in S1 is restarted. Then, after all the landing pitches of R, G, and B match the target values, it is determined in S8 whether or not the RG landing pitch and the GB landing pitch calculated in S6 match the target values, and they match. If not, the Y-axis adjustment is performed in S9, and then the test printing in S1 is restarted.

As described above, in the conventional method, every time the pitch of the coating target portion changes, test printing is performed, the landing pitch of the droplets is measured, and the rotation angle is further finely adjusted based on the result. , It was necessary to repeat the driving of the rotation angle and the driving in the Y direction until the target threshold value was reached. Even in the case of this method, if the definition is low and the target threshold value is large, the adjustment can be made by pushing in once or twice, which does not cause much problem.

However, in recent years, as the demand for higher definition display devices has increased, the pitch of the coating target portion has become smaller, and it has become necessary to align the landing pitch of the droplets ejected from the nozzle with great precision. When applying such a high-definition display device, the impact position shifts due to the ejection angle habit of the droplets ejected from each nozzle, and the impact position due to the relative movement of the object to be coated and the inkjet head. The deviation has come to have a great influence on the coating position accuracy.

Therefore, when applying to a high-definition display device by the above-mentioned conventional method, it is necessary to stop the normal printing operation and perform the above-mentioned work of pursuing the landing pitch many times each time the pitch of the coating target portion changes. As a result, there is a problem that the operating rate of the inkjet printing apparatus does not increase. In addition, it was necessary to prepare a dedicated test board in order to drive the landing pitch, or to provide a wide test printing area on the production board.

The subject of the present invention is that even if the pitch of the coating target portion of the object to be coated changes, the optimum head rotation amount is determined without performing test printing each time, and the landing pitch of the droplets and the coating target portion are determined. It is an object of the present invention to provide an inkjet printing method for accurately adjusting pitches and an inkjet printing apparatus using the method.

The main invention for solving the above-mentioned problems is
An inkjet printing method in which droplets are ejected from the inkjet head while scanning the inkjet head relative to the object to be coated, and ink is applied onto the object to be coated.
A memory that stores the landing position deviation characteristic obtained based on the landing position deviation of the droplet ejected from the inkjet head from the target position when the inkjet heads have different first and second rotation angles. The first step of reading the data related to the landing position deviation characteristic from the means, and
The target rotation angle of the inkjet head is obtained based on the landing position shift characteristic, the arrangement pitch of the droplet ejection nozzles of the inkjet head, and the coating target pitch of the coating object in the direction orthogonal to the scanning direction. At the same time, a second step of generating a print pattern corresponding to the target rotation angle, and
A third step of controlling the inkjet head based on the target rotation angle and the printing pattern to eject droplets to the coating target portion on the coating object.
It is an inkjet printing method having.

Also, in other aspects,
An inkjet printing device that ejects droplets from the inkjet head while scanning the inkjet head relative to the object to be coated to apply ink onto the object to be coated.
A memory that stores the landing position deviation characteristic obtained based on the landing position deviation of the droplet ejected from the inkjet head from the target position when the inkjet heads have different first and second rotation angles. Means and
The target rotation angle of the inkjet head is obtained based on the landing position shift characteristic, the arrangement pitch of the droplet ejection nozzles of the inkjet head, and the coating target pitch of the coating object in the direction orthogonal to the scanning direction. At the same time, a calculation means for generating a print pattern corresponding to the target rotation angle, and
With
It is an inkjet printing apparatus that controls the inkjet head based on the target rotation angle and the printing pattern to eject droplets to a coating target portion on the coating object.

According to the above aspect of the present invention, even if the pitch of the coating target portion of the object to be coated changes, the landing pitch of the droplets ejected from the inkjet head can be set as the coating target without performing test printing each time. It can be adjusted to the pitch of the part.

Perspective view of the inkjet printing apparatus of one embodiment Top view showing the substrate of the object to be coated according to one embodiment. Top view explaining the landing position shift due to the ejection angle habit of the droplet ejected from the inkjet head. Side view for explaining the landing position shift due to the ejection angle habit of the droplet ejected from the inkjet head. Top view explaining the landing position shift due to the ejection angle habit of the droplet when the inkjet head has a rotation angle of 0 degree. Top view explaining the landing position shift due to the ejection angle habit of the droplet when the inkjet head has a rotation angle of φ degree. Top view explaining the landing position of the droplet ejected from the inkjet head when the object to be coated is stopped. Side view explaining the landing position of the droplet ejected from the inkjet head when the object to be coated is stopped. Top view explaining the landing position of the droplet ejected from the inkjet head when the object to be coated is traveling. Side view explaining the landing position of the droplet ejected from the inkjet head when the object to be coated is traveling. Top view explaining the landing position of the ejected droplet when the rotation angle of the inkjet head is 0 degree when the object to be coated is traveling. Top view explaining the amount of displacement in the Y direction between the landing position of the ejected droplet when the rotation angle of the inkjet head is 0 degrees and the coating target portion of the coating object when the object to be coated is traveling. Top view explaining the X-direction distance between the landing position of the ejected droplet and the Y-axis when the object to be coated is traveling and the rotation angle of the inkjet head is 0 degree. Top view explaining the landing position when the ejection timing is corrected so that the landing position when the rotation angle of the inkjet head is 0 degree when the object to be coated is traveling is on the Y axis. Top view explaining the landing position of a droplet when printed on an object to be coated with the ejection timing corrected so that the landing position is on the Y axis at a rotation angle of 0 degree of the inkjet head. Enlarged view of part A in FIG. 8d Top view for explaining the amount of displacement in the Y direction between the landing position of the ejected droplet and the coating target portion of the coating object when the rotation angle of the inkjet head is θ when the object to be coated is traveling. A plan view for explaining the X-direction distance between the landing position of the ejected droplet and the Y-axis when the rotation angle of the inkjet head is θ when the object to be coated is traveling. Top view explaining the landing position when the ejection timing is corrected so that the landing position when the rotation angle of the inkjet head is θ when the object to be coated is traveling is on the Y axis. Top view explaining the landing position of a droplet when printing on an object to be coated with the ejection timing corrected so that the rotation angle of the inkjet head is θ and the landing position is on the Y axis. Enlarged view of part A in FIG. 9d Top view for explaining the amount of displacement in the Y direction between the landing position of the ejected droplet and the coating target portion of the coating object when the rotation angle of the inkjet head is φ when the object to be coated is traveling. Top view explaining the X-direction distance between the landing position of the ejected droplet and the Y-axis when the rotation angle of the inkjet head is φc when the object to be coated is traveling. Top view explaining the landing position when the ejection timing is corrected so that the landing position when the rotation angle of the inkjet head is φc is on the Y axis when the object to be coated is traveling. Top view explaining the landing position of a droplet when it is applied to an object to be coated with the ejection timing corrected so that the rotation angle of the inkjet head is φc and the landing position is on the Y axis. Enlarged view of part A in FIG. 10d Top view explaining the landing position before and after θ rotation of the inkjet head when the object to be coated is scanning at a velocity V. Top view explaining the landing position when the inkjet head is rotated by φ when the object to be coated is scanning at a velocity V. Top view explaining the landing position before and after θ rotation of the inkjet head when the object to be coated is stopped. The figure explaining the case where the inkjet head is adjusted so that it matches the pitch of the coating target part of the coating object in a conventional example. Flow chart for adjusting the pitch of the coating target portion of the object to be coated and the pitch of the droplets ejected from the inkjet head in the conventional example.

Hereinafter, the inkjet printing apparatus 40 according to the present embodiment will be described with reference to the drawings.

[Configuration of inkjet printing equipment]
FIG. 1 is a perspective view of an inkjet printing apparatus according to an embodiment. The overall picture of the inkjet printing apparatus 40 will be described with reference to FIG.

As shown in FIG. 1, the inkjet printing apparatus 40 includes at least a pedestal 18 that supports the apparatus, a surface plate 17 installed on the pedestal 18, and a substrate transport stage that transports the substrate in the X direction installed on the surface plate 17. 30, the head unit 32, the head unit transfer stage 33 that conveys the head unit 32 in the Y direction orthogonal to the substrate transfer stage 30, and two that support both ends of the head unit transfer stage 33 on the surface plate 17. The support portion 16 of the above is provided.

The substrate transfer stage 30 includes a substrate guide rail 5, a substrate slider 4 guided by the substrate guide rail 5 and slidably supported in the X direction, and a substrate rotation mechanism 3 installed on the substrate slider 4. And a substrate suction table 2 installed on the substrate rotation mechanism 3. The substrate transfer slider 4 is feedback-controlled by a substrate transfer line motor 6, a substrate transfer position detecting means 7, and a substrate transfer stage control means (not shown).

Further, the substrate rotation mechanism 3 is provided with a substrate rotation angle detecting means (not shown) and a substrate rotation driving means (not shown), and is configured to be precisely positioned at a target rotation angle by a substrate rotation mechanism control means (not shown). doing.

On the other hand, the head unit transfer stage 33 is formed by a head unit transfer guide rail 13 and a head unit transfer slider 12 guided by the head unit transfer guide rail 13 and slidably supported in the Y direction. The head unit transfer slider 12 is feedback-controlled by a head unit transfer linear motor 14, a head unit transfer position detecting means 15, and a head unit transfer stage control means (not shown). ing.

The head unit 32 is configured by mounting an inkjet head unit 23 and an alignment camera 21 on a head unit base 22 attached to a slider 12 for transferring a head unit. Further, the inkjet head unit 23 mounts the head rotation mechanism 10 on the head unit base 22 via the bracket 11, and mounts the inkjet head 8 under the head rotation mechanism 10 via the head bracket 9. The head rotation mechanism 10 includes a head rotation angle detecting means (not shown) and a head rotation driving means (not shown) inside, and is configured to be precisely positioned at a target rotation angle by a head rotation mechanism control means (not shown). Has been done.

Further, the inkjet head 8 is provided with a plurality of droplet ejection nozzles, and the inkjet head control means 100 provides each droplet ejection nozzle of the inkjet head 8 based on the detection position by the substrate transport position detecting means 7. It is configured so that the discharge timing can be controlled. The plurality of droplet ejection nozzles of the inkjet head 8 are arranged side by side in a line at a predetermined pitch, for example.

The inkjet head control means 100 includes, for example, a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), an input port, an output port, and the like, and performs an ejection operation of the inkjet head 8. It is a controlling microcomputer.

The inkjet head control means 100 includes a storage means 110 that stores the landing position shift characteristic when droplets are ejected from the inkjet head 8, the landing position shift characteristic, and the arrangement pitch of the droplet ejection nozzles of the inkjet head 8. It has a calculation means 120 that obtains a target rotation angle of the inkjet head 8 based on a coating target pitch of an object to be coated in a direction orthogonal to the scanning direction and generates a print pattern corresponding to the target rotation angle. .. The landing position deviation characteristic is obtained based on the landing position deviation from the target position of the droplet ejected from the inkjet head 8 when the inkjet heads 8 have different first and second rotation angles. Details will be described later).

In the first embodiment, both the substrate transfer stage 30 and the head unit transfer stage 33 employ an air bearing mechanism in order to realize highly accurate positioning.

[Operation of inkjet printing device]
Next, the operation of the inkjet printing apparatus 40 having the above configuration will be described with reference to FIGS. 2 to 13. FIG. 2 is a plan view showing the substrate of the object to be coated according to the first embodiment. The substrate 1 is surrounded by the equipment 1a, the alignment marks 1b formed at the four corners on the equipment 1a, the bank 1c that acts as a bank to prevent the printed ink from overflowing, and the bank 1c, and is arranged at a constant pitch. It is composed of a coating target portion 1d and a test printing area 1e for measuring the landing position of a droplet, and the landing measurement area 1f in the test printing area 1e is an extension of 1d at the same pitch as the coating target portion 1d. It is formed on a line. The coating target portion 1d is an area constituting the pixels of the display panel, and the landed droplets get wet and spread, whereas the landing measurement area 1f has liquid repellency so that the landed droplets stay in a circle. The position of the landing measurement area 1f with respect to the center of the circle can be measured by capturing the position with the alignment camera 21 and processing it with an image processing means (not shown).

The coating area 1g is an area having liquid repellency similar to the landing measurement area 1f, and is for measuring the rough landing position of the droplet when the droplet does not enter the circle of the landing measurement area 1f. It is provided for use as an area.

<When the substrate 1 and the inkjet head 8 do not move relative to each other>
Next, regarding the relationship between the position of the droplet ejection nozzle of the inkjet head 8 and the landing position where the droplet ejected from the droplet ejection nozzle reaches the substrate 1 when the substrate 1 and the inkjet head 8 do not move relative to each other. This will be described with reference to FIGS. 3a, 3b, 4a, and 4b.

FIG. 3a is a plan view for explaining the landing position shift due to the ejection angle habit of the droplet ejected from the inkjet head 8, and FIG. 3b is a side view.

FIG. 4a is a plan view for explaining the landing position shift due to the ejection angle habit of the droplet when the rotation angle of the inkjet head 8 is 0 degree, and FIG. 4b is a plan view of the droplet when the rotation angle of the inkjet head is φ degree. It is a top view explaining the landing position deviation by a discharge angle habit.

The inkjet head 8 in FIG. 3a has four droplet ejection nozzles indicated by dotted circles, and the hole positions thereof are n ₁ , n ₂ , n ₃ , and n ₄ . Each droplet ejection nozzle has a habit in the ejection direction, and when landing on the surface of the substrate 1 separated from the nozzle surface of the inkjet head 8 by a distance G as shown in FIG. 3b, the position is a solid circle. It reaches a position different from the position directly under _{n 1} , n ₂ , n ₃ , and n ₄ , such as P ₁ , P ₂ , P ₃ , and P _{4 shown.} This amount of misalignment is referred to as landing misalignment due to discharge angle habit.

The landing position shift due to the ejection angle habit from each droplet ejection nozzle is determined by the shape accuracy of the hole of the droplet ejection nozzle, the surface condition around the droplet ejection nozzle, and the like, and is fixed in the inkjet head 8. Become a habit. Therefore, as in the inkjet head 8 shown in FIG. 4a, even when the rotation angle is rotated by φ degrees as shown in FIG. 4b, droplets are ejected from the head as compared with the case where the rotation angle of the inkjet head 8 is 0 degrees. nozzle position _{n 1, n 2, n 3} , landing positions relative to _{n 4 P 1, P 2,} P 3, P 4 will be displaced in the same direction in the ink jet head 8. That is, FIG. 4b, which is a plan view when the inkjet head 8 is rotated by φ degree, is a position where FIG. 4a is rotated by φ degree as it is. The point O in FIGS. 4a and 4b is a rotation axis.

<When the substrate 1 and the inkjet head 8 move relative to each other>
Next, with respect to the landing position when the substrate 1 is traveling at a constant velocity V with respect to the inkjet head 8 and the droplet is ejected from the droplet ejection nozzle of the inkjet head 8 toward the substrate 1, FIGS. 5a and 5b. 6a and 6b will be described.

FIG. 5a is a plan view illustrating the displacement of the landing position of the droplet ejected from the inkjet head 8 when the object to be coated is stopped, and FIG. 5b is a side view thereof. FIG. 6a is a plan view illustrating the displacement of the landing position of the droplets ejected from the inkjet head when the object to be coated is traveling at a speed V, and FIG. 6b is a side view thereof.

The position where the liquid droplets ejected from the nozzles of the n ₁ position of the inkjet head 8 in a state where the substrate 1 is stopped lands on the substrate 1 as shown in FIG. 5a and P _1. The amount of the misalignment of P _{1 with respect to n 1} is the landing misalignment due to the discharge angle habit described in FIG. Droplets discharged from the nozzles of the n ₁ position during travel of the substrate 1 at a constant speed V with respect to it, to fly with the speed, it is necessary time before the droplet reaches the substrate 1 .. When the time with Delta] t, so the substrate during traveling by Delta] t × V, with respect to the landing position P ₁ when landing positions to Q ₁ on the substrate 1 of the droplets that landed the substrate 1 is stopped It will shift.

Actually, while the droplets are flying toward the substrate 1, the droplets are swept by the influence of the deceleration due to the resistance of air and the influence of the wind generated by the running of the substrate 1, so that the position is more complicated. It will be out of alignment. _{The landing position deviation ΔX 1v} in the traveling direction caused by the traveling of the substrate 1 is referred to as the landing position deviation due to traveling. The landing position shift due to this running is the landing position shift due to the running of the substrate 1, and is basically a position shift that occurs in the running direction. Unlike the position shift due to the ejection angle habit of the inkjet head 8, the inkjet head 8 Even when the ink jet head 8 is rotated, it does not rotate together with the rotation of the inkjet head 8.

In the case that the substrate 1 is stopped As described above, the landing position on the substrate 1 of the droplets discharged from the nozzle position n ₁ becomes P ₁ only landing position shift due to the jetting angle propensity respect, when the substrate is traveling at a speed V, landed on the relative P ₁ was displaced landing positions by jetting angle habit, it was added further landing position shift ΔX1v by traveling in the traveling direction of the substrate 1 position do.

Next, a method of printing droplets on the coating target portion 1d of the substrate 1 will be described.

(1) First, an alignment method of the substrate 1 will be described. The substrate 1 is adsorbed and fixed on the substrate suction table 2, the board transfer stage 30 and the head unit transfer stage 33 are moved, and the alignment marks 1b at the four corners of the board 1 are placed under the alignment camera 21 mounted on the head unit 32. The alignment camera 21 takes an image of the alignment mark 1b, and the position of the alignment mark 1b is measured by an image recognition means (not shown). On the other hand, based on the detection position by the substrate transfer position detecting means 7 and the detection position by the head unit transfer position detecting means 15 at that time, the traveling direction of the substrate transfer stage 30 and the coating target of the substrate 1 by the control means (not shown). The substrate rotation mechanism 3 is driven and adjusted so that the directions of the portions 1d are parallel to each other.

(2) Next, a method of adjusting the position between the droplet ejection nozzle and the coating target portion 1d of the substrate 1 will be described. FIG. 7 is a plan view illustrating the landing position of the ejected droplets when the object to be coated travels at a speed V and the inkjet head is at the first rotation angle (here, the rotation angle is 0 degrees).

The dotted circles n ₁ , n ₂ , n ₃ , and n ₄ in FIG. 7 are the positions of the droplet ejection nozzles in the inkjet head 8, and the solid circles P ₁ , P ₂ , P ₃ , and P ₄ are liquids. represents misaligned landing position when the jetting angle habit of the droplets discharged from droplet discharge nozzles to reach the substrate 1, a circle to Q ₁ double solid _{lines, Q 2, Q 3, Q} 4 is P _1, P _2, P _3, further substrate 1 with respect to P ₄ represents a landing position plus running by landing position shift caused by traveling. In FIG. 7, the inkjet head 8 is positioned at a rotation angle of 0 degrees around the rotation axis O point so that the droplet pitch in the Y direction of the inkjet head 8 _{matches the pitch W 0 of the coating target portion 1d.}

<Calculation of landing position shift characteristics>
Next, a method of calculating the landing position deviation characteristic (hereinafter, abbreviated as “landing position deviation characteristic”) that occurs when the inkjet printing apparatus 40 ejects droplets from the inkjet head 8 will be described.

FIG. 8a shows the state of FIG. 7, that is, the landing position of the droplets ejected when the object to be coated travels at a speed V and the rotation angle of the inkjet head is 0 degrees, and the coating target portion 1d of the object to be coated. It is a top view explaining the amount of displacement in the Y direction of. In Figure 8a, the landing position of the droplet _{Q 1, Q 2, Q 3} , Q 4 in the Y direction position as the coating target portion 1d, respectively [Delta] Y ₁₀ central axis of the Y direction distance of, ΔY _20, ΔY _30, ΔY It is represented by _40. Regarding the alignment of the inkjet head 8 and the substrate 1 in the Y direction, the alignment is performed so that the total error of _{ΔY 10} , ΔY ₂₀ , ΔY ₃₀ , and ΔY _{40 is minimized.}

FIG. 8b shows the state of FIG. 7, that is, the distance between the landing position of the droplets ejected when the rotation angle of the inkjet head 8 is 0 degrees and the Y-axis in the X direction when the object to be coated travels at a speed V. It is a top view to explain. In Figure 8b, it represents the X direction distance between the Y-axis of the landing position of the droplet _{Q 1, Q 2, Q 3} , Q 4 in _{X 1S0, X 2S0, X 3S0} , X 4S0. Then, showing the landing position in the case of correcting the ejection timing corresponding to the X direction distance _{X 1S0, X 2S0, X 3S0} , X 4S0 Figure 8c. By adjusting the ejection timing as shown in FIG. 8c, the landing position of the droplets ejected from all the droplet ejection nozzles and reaching the substrate 1 can be aligned substantially on the Y-axis. This print pattern is referred to as a first print pattern. In this state, the landing position when printed on the landing measurement area 1f of the substrate 1 and the coating target portion 1d is shown in FIG. 8d. This printing is referred to as a first printing step. In FIG. 8d, the droplets in the coating target portion 1d are also indicated by double circles, but in reality, since the coating target portion 1d is hydrophilic, the landed droplets are wet and spread. On the other hand, since the landing measurement area 1f is liquid-repellent, the landed droplets land in a circle in the circle surrounding the landing measurement area 1f as shown in FIG. 8d. FIG. 8e is an enlarged view of part A in FIG. 8d. By imaging the landing measurement area 1f with the alignment camera 21 and performing image processing, the Y-direction positional deviation between the circle of the landing position measurement area 1f at _{pitch W 0 and the circle of the droplet is ΔY i0} and the position in the X direction. By detecting the deviation ΔX _i0 (i = 1, 2, 3, 4), the landing position deviation of the droplet can be accurately measured. This measurement is referred to as the first landing position deviation detection step.

As a result, from the landing position deviation measurement result in the landing measurement area 1f, ΔX _i0 and ΔY _{i0, and the correction amount X iS0} shifted by the discharge timing correction in FIG. 8c, the landing when the discharge timing correction is not performed. The position can be calculated accurately. This calculation step is referred to as the first landing position calculation step. Then, this landing position data is used as the first landing position data.

Then, when the pitch of the coating target portion 1d is W ₀ is smaller than W _1, when coating with the inkjet head 8 is rotated θ about the rotation axis O point to match the droplet pitch W ₁ for a description do.

FIG. 9a shows the landing position of the ejected droplets at the second rotation angle (here, the rotation angle θ degree) of the inkjet head 8 when the object to be coated travels at a speed V, and the coating target of the object to be coated. It is a top view explaining the amount of position deviation in the Y direction with respect to part 1d. Represents landing positions to _Q 1 _{drop, Q 2, Q 3, Q} 4 in the Y-direction position and the Y direction distance between the center axis of the coating target portion 1d respectively _{ΔY 1θ, ΔY 2θ, ΔY 3θ} , in [Delta] Y _4? There is. Regarding the alignment of the inkjet head 8 and the substrate 1 in the Y direction, the alignment is _{performed so that} the total error of _{ΔY 1θ} , ΔY _2θ , ΔY _3θ , and ΔY 4θ is minimized.

FIG. 9b describes the state of FIG. 9a, that is, the distance between the landing position of the ejected droplet and the Y-axis when the rotation angle of the inkjet head 8 is θ when the object to be coated travels at a speed V. It is a plan view.

Landing position of the droplet _{Q 1, Q 2, Q 3} , the X direction distance between the Y axis _{Q 4 X 1Sθ, X 2Sθ,} X 3Sθ, is represented by X _4Esushita. And shows the X-direction distance _{X 1Sθ, X 2Sθ, X 3Sθ} , the landing position in the case of correcting the ejection timing corresponding to X _4Esushita Figure 9c. By adjusting the ejection timing as shown in FIG. 9c, the landing positions of the droplets ejected from all the droplet ejection nozzles and reached the substrate 1 can be substantially aligned on the Y-axis. This print pattern is referred to as a second print pattern. In this state, the landing position when printed on the landing measurement area 1f of the substrate 1 and the coating target portion 1d is shown in FIG. 9d. This printing is referred to as a second printing step. In FIG. 9d, the droplets in the coating target portion 1d are also indicated by double circles, but in reality, since the coating target portion 1d is hydrophilic, the landed droplets are wet and spread. On the other hand, since the landing measurement area 1f is liquid-repellent, the landed droplets land in a circle in the circle surrounding the landing measurement area 1f as shown in FIG. 9d. FIG. 9e is an enlarged view of part A in FIG. 9d. By imaging the landing measurement area 1f with the alignment camera 21 and performing image processing, _{the Y-direction positional deviation ΔY iθ} and the X-direction position between the circle of the landing position measurement area 1f of _{pitch W 1 and the circle of the droplet.} By detecting the deviation ΔX _iθ (i = 1, 2, 3, 4), the landing position deviation of the droplet can be accurately measured. This measurement is referred to as a second landing position deviation detection step.

As a result, from the landing position measurement result in the landing measurement area 1f, ΔX _iθ , ΔY _{iθ, and the correction amount X iSθ} shifted by the discharge timing correction in FIG. 9c, the landing position when the discharge timing correction is not performed. Can be calculated accurately. This calculation step is referred to as a second landing position calculation step. Then, this landing position data is used as the second landing position data.

The relative moving speed of the inkjet head 8 and the substrate 1 in the first printing step and the relative moving speed of the inkjet head 8 and the substrate 1 in the second printing step are set to be the same.

As described above, for the substrate having the pitch of the coating target portion 1d of W _{0 and} the substrate of the coating target portion 1d having the pitch of W ₁ , the pitch of the droplets is adjusted by rotating the inkjet head 8 by θ degrees. Print according to the pitch and measure each landing position accurately.

Then, based on the measurement results of the landing positions on the above two types of substrates 1, the optimum rotation angle of the inkjet head 8 that minimizes the landing deviation with respect to the substrate of an arbitrary coating target portion pitch is calculated, and test printing is performed. Allows application without.

The method will be described with reference to FIGS. 11 and 12.

FIG. 11 is a diagram showing the relationship between the landing positions of one nozzle in the inkjet head 8 when the rotation angle around the head rotation center O point is 0 degree and when the nozzle is rotated by θ degree from the rotation angle. Here, the X coordinate of the head rotation center O point is δx, and the Y coordinate is δy. Further, when the rotation angle is 0 degrees, the landing position is Q ₀ , _{the X coordinate of Q 0} is Xa, the Y coordinate is Ya, and it _{is expressed as Q 0} (Xa, Ya). On the other hand, when the rotation angle is θ degree, the landing position is Q _θ , _{the X coordinate of Q θ} is X b, the Y coordinate is Y b, and it _{is expressed as Q θ} (Xb, Yb). Furthermore the positional deviation in the X direction of landing positions by the running of the substrate 1 and [Delta] X _V.

When the coating is applied while the substrate 1 is running, the landing position deviation of the droplets ejected from the inkjet head 8 and landing on the substrate 1 is due to the ejection angle habit when the droplets are ejected from the droplet ejection nozzle as described above. The landing position shift due to the running of the substrate 1 is added to the misalignment, the landing position shift due to the ejection angle habit rotates with the rotation of the inkjet head 8, and the landing position shift due to the running of the substrate 1 rotates with the inkjet head 8. It is determined by the traveling direction of the substrate 1 regardless of. Therefore the rotation angle 0 ° and theta of the landing position _P 0, P _theta by the discharge angle habit only for each of the inkjet head 8, respectively, X coordinate Xa-[Delta] X _V of _{P 0,} Y coordinate Ya, P _theta X coordinate Xb-ΔX _V, Y coordinate is the Yb of.

Since P _θ corresponds to the position where P ₀ is rotated by θ degrees around the head rotation axis O point, _{the relationship between the P θ} points and the P ₀ points is expressed by equations (1) and (2) according to the equation of coordinate rotation. It can be expressed as.

The formula (1), the equation (2), and Y-coordinate δy of the rotation axis of the ink jet head 8, the positional displacement [Delta] X _V by the driving of the substrate 1, the formula (3), be calculated by the equation (4) can. Here, the X-axis coordinate δx of the rotation axis of the inkjet head 8 needs to be measured separately. The measurement method will be described later.

If the X coordinate δx of the head rotation center O of the inkjet head 8 is obtained in advance as described above, the rotation angle of the head of the inkjet head 8 is 0 degrees (in the method of printing while traveling the substrate 1 at a speed V). _{Landing position Q 0} (Xa, Ya) (first landing position data), Q _θ (Xb, Yb) (first rotation angle) and θ degree (second rotation angle) by measuring the second landing position data), it is possible to determine the landing position shift [Delta] X _V by the running of the substrate, if Motomare is [Delta] X _V, it is possible to determine the landing position shift due to the jetting angle habit. This calculation step is referred to as a landing position deviation characteristic calculation step.

The data related to the landing position shift characteristic calculated in this way is stored in the storage means 110 as data showing the unique characteristics of the inkjet head 8 used here. In the droplet ejection operation for calculating the landing position deviation characteristic, for example, when printing the coating target portion 1d, the droplet is applied to the landing measurement area 1f together, and the droplet is applied within the landing measurement area 1f. It can be carried out by measuring the landing position deviation.

<Operation when printing is executed>
The inkjet printing device 40 (calculation means 120) obtains a target rotation angle of the inkjet head 8 at the time of printing by utilizing the landing position shift characteristic calculated above, and obtains a printing pattern corresponding to the target rotation angle. Generate. In the present embodiment, when droplets are ejected from each droplet ejection nozzle of the inkjet head 8, the rotation angle at which the positional deviation of the coating target portion 1d of the object to be coated is minimized is set by the inkjet head at the time of printing. The target rotation angle of 8 is set (hereinafter, also referred to as “optimal rotation angle”). However, the target rotation angle of the inkjet head 8 is set to a rotation angle at which the positional deviation of the coating target portion 1d of the coating target object becomes equal to or less than the threshold when the droplets are ejected from each droplet ejection nozzle of the inkjet head 8. You may.

First, landing position shift characteristics Motoma' above (i.e., running by landing position deviations [Delta] X V of the substrate _1, and the landing displacement caused by the ejection angle curls), and a head rotation center O (.delta.x, .delta.y) of the inkjet head 8 from In the method of printing while traveling the substrate 1 at a speed V, a method of calculating the landing position at an arbitrary third rotation angle φ of the inkjet head 8 will be described with reference to FIG.

FIG. 12 is a diagram for explaining the landing position deviation when the inkjet head 8 has a head rotation angle of 0 degrees and when the inkjet head 8 has a head rotation angle of φ degrees.

First, the calculation means 120 reads out the data related to the landing position deviation characteristic stored in the storage means 110, and landed by traveling from the X coordinate _{of the landing position Q 0 (Xa, Ya) at the rotation angle of 0 degrees of the inkjet head 8.} By subtracting the misalignment ΔX _{V , the landing position P 0} (Xa−ΔX _V , Ya) when there is only a discharge angle habit is obtained. Then, the calculation means 120 _{obtains the landing position P φ} (Xd, Yd) _{when there is only a discharge angle habit in which the P 0} point is rotated by φ degrees around the head rotation center O point, and the X coordinate of _{this P φ point.} a by adding the landing position deviation [Delta] X _V by the driving of the substrate 1, obtaining the landing position of the rotation angle _{φ Q φ (Xe, Ye)} . Expressing this by an equation, _{the coordinates of the P φ} point can be expressed by equations (5) and (6), and _{the coordinates of the Q φ} point can be expressed by equations (7) and (8). The step of calculating the landing position of the inkjet head 8 at the third rotation angle φ is referred to as the landing position prediction step.

The calculation means 120 changes the third rotation angle φ of the inkjet head 8 in various ways, and calculates the landing position at each of the plurality of third rotation angles φ.

Next, the calculation means 120 is based on the arrangement pitch of the droplet ejection nozzles of the inkjet head 8 and the coating target pitch of the coating target portion 1d of the coating target in the direction orthogonal to the scanning direction. The optimum rotation angle φc of the inkjet head 8 when ejecting droplets from the inkjet head 8 is obtained from the coating target portion 1d. The calculation means 120 calculates, for example, an evaluation value related to the landing position deviation of the droplet with respect to the coating target portion 1d at each of the plurality of third rotation angles φ of the inkjet head 8, and is optimal based on this evaluation value. Find the rotation angle φc.

Formulas (7) and (8) for calculating the landing position of one droplet ejection nozzle at the rotation angle φ of the inkjet head 8 are shown. Here, when a plurality of droplet ejection nozzles are provided on the inkjet head 8, the landing position coordinates at the rotation angle of the inkjet head 8 of the i-th droplet ejection nozzle at 0 degrees (first rotation angle) are set to ( _Xia). , Y _ia ), the landing position coordinates at the rotation angle θ degree (second rotation angle) are (X _ib , Y _ib ), and the amount of misalignment due to the running of the i-th nozzle is ΔX _iv , the rotation angle φ ( If the landing position coordinates at the third rotation angle) are ( _Xie , _Yie ), the values can be expressed as equations (9) and (10).

Here, ΔX _iv can be expressed by the equation (11). When the i-th droplet Y coordinates of the coating target portion of the discharge nozzle Y _ti, the _i-th droplet Y coordinate of the landing position of the discharge nozzle and Y _ie, the difference [Delta] Y _Iø is expressed by equation (12) be able to. The ΔY _iφ and ΔX _iv are shown in FIG. 10a. In each figure, i is four droplet ejection nozzles 1, 2, 3, and 4. Then, in order to obtain the optimum rotation angle φc of the inkjet head 8, the calculation means 120 uses the squared sum average Δt of _{the Y-direction positional deviation ΔY iφ of all the droplet ejection nozzles as an evaluation value, as shown in the equation (13).} calculate. Then, the calculation means 120 changes φ, calculates the average sum of squares Δt for each φ, and obtains the value of φ that minimizes Δt. The φ at which this Δt is the minimum is the optimum rotation angle φ _C of the inkjet head 8.

Further, the calculation means 120 calculates the offset amount Δy in the Y direction by the equation (14). This Δy is reflected in printing by offsetting when aligning the substrate 1 and the inkjet head 8.

Then, the calculation means 120 calculates the landing position coordinates _Xieφc of each nozzle in the X direction in the X direction by the equation (15), and corrects the discharge timing of the amount corresponding to _−Xieφc. The print pattern corrected for the ejection timing is referred to as an optimum print pattern, and the generation process thereof is referred to as an optimum print pattern generation process.

Incidentally, in the case of setting the rotation angle of the inkjet head 8 to the optimum rotation angle phi _C, the impact point coordinate Y _Iefaishi the Y direction of each nozzle is calculated by equation (16), positional deviation in the Y direction from the target coordinates ΔY _ieφc is calculated by the equation (17). Then, the Y coordinate of the landing position when the offset in the Y direction is taken into consideration is _Yieφc −Δy.

The inkjet printing apparatus 40 (inkjet head control means 100) positions the inkjet head 8 at the optimum rotation angle φ _c calculated above and the offset amount Δy in the Y direction, and prints according to the above optimum printing pattern. As a result, the droplet can be ejected so that the positional deviation with respect to the coating target portion 1d is minimized.

At the time of printing, the inkjet printing apparatus 40 has a substrate transfer stage so that the relative moving speed between the inkjet head 8 and the substrate 1 is the same as the speed in the first printing step and the second printing step described above. 30 is controlled.

The above situation is shown in FIGS. 10b to 10e. FIG. 10b shows the distance between the landing positions of the first, second, third, and fourth droplet ejection nozzles and the Y axis in the X direction when the head rotation angle of the inkjet head 8 _{is set to the optimum rotation angle φ c obtained above.} It is a figure which shows. FIG. 10c is a diagram showing the landing position when the landing position of each droplet discharge nozzle of FIG. 10b and the discharge timing of the Y-axis are corrected by the distance in the X direction. When the ejection timing is corrected by the opposite direction of the amount calculated by the equation (15) _−XieΦc , the landing position of each droplet ejection nozzle overlaps on the Y axis. A diagram in which droplets are applied to the substrate 1 in that state is shown in FIG. 10d. By setting the rotation angle of the inkjet head 8 to the optimum rotation angle φc, the positional deviation between the landing position of each nozzle and the coating target position is minimized. FIG. 10e shows an enlarged view of the landing position in the landing measurement area 1f when actually applied. In this figure, the landing positions of the droplets ejected from the third and fourth droplet ejection nozzles in the landing measurement area are shown. _{The amount of displacement ΔX 3φc} and ΔX _4φc of the actually landed droplet from the target position in the X direction are almost the target positions, but if you want to pursue this further, the discharge timing for this amount of displacement It is possible to make it even smaller by performing correction.

<How to find the coordinates of the center of rotation of the inkjet head>
Next, how to obtain the coordinates of the head rotation center O (δx, δy) of the inkjet head 8 will be described with reference to FIG. FIG. 13 is a plan view illustrating the landing position of the inkjet head 8 before and after the θ rotation when the object to be coated is stopped. Since the object to be printed is stopped, the displacement due to running does not occur, and only the displacement due to the ejection angle habit from the droplet ejection nozzle occurs. Therefore, the landing position before rotation is P _0V0 (Xa _V0 , Ya). _V0), when the landing position after θ rotation _{P θV0 (Xb V0, Yb V0} ), P θV0 because corresponds to position rotated θ a P _0V0 around point O, the relationship between the coordinates (18 ), Equation (19).

Then, when the coordinates (δx, δy) of the point O are obtained from the equations (18) and (19), the equations (20) and (21) are obtained.

The work of specifying the coordinates of the head rotation center O point may be performed only once at the beginning when the inkjet head 8 is attached to the head rotation mechanism 10. It is not necessary to use all the nozzles, and it is preferable to select and perform this work from two nozzles that are separated from each other near both ends of the inkjet head 8 and have high ejection reproducibility.

As described above, according to the inkjet printing apparatus 40 according to the present embodiment, the target positions of the droplets ejected from the inkjet head 8 when the inkjet heads 8 have different first and second rotation angles. Based on the landing position deviation characteristic calculated based on the landing position deviation from, the optimum head rotation amount of the inkjet head 8 is set for the coating target portion 1d of an arbitrary pitch without test printing. It becomes possible to print.

This method can be carried out by applying a droplet to the landing measurement area 1f together and measuring the landing position deviation within 1f when printing the actual coating target portion 1d. The landing position deviation is measured during the production of the substrate 1 of the target portion pitch W _{0 and} the substrate 1 of the coating target portion pitch W ₁ , and based on the measurement result, the landing position is relative to the substrate 1 of an arbitrary coating target portion pitch. The head rotation angle of the inkjet head 8 can be set so that the deviation is minimized. As a result, according to the inkjet printing apparatus 40 according to the present embodiment, even in high-definition printing in which it is necessary to consider even the landing position deviation due to the ejection angle habit of the droplet ejection nozzle, the test printing or the like is operated. High-precision printing is possible while minimizing the process of lowering the rate.

As described above, according to the inkjet printing apparatus 40 according to the present embodiment, the impact habit can be measured on the actual production substrate without using a special substrate for measuring the impact habit, and based on the result. Accurate coating can be performed on a substrate with an arbitrary coating target pitch without test printing. As a result, it is possible to print a high-definition display panel with a high operating rate.

The inkjet printing apparatus according to the above aspect of the present invention is effective for applying ink or the like to a high-definition, constant-pitch printing object, and prints an organic EL light emitter, a hole transport layer, or an electron transport layer. Alternatively, it can be applied to an inkjet printing apparatus for printing a color filter or the like.

1 Substrate (object to be coated)
1a Equipment 1b Alignment mark 1c Bank 1d Coating target 1e Test printing area 1f Landing measurement area 1g Coating area 2 Board suction table 3 Board rotation mechanism 4 Board slider 5 Board guide rail 6 Board transfer linear motor 7 Board transfer position detection Means 8 Inkjet head 9 Bracket 10 Head rotation mechanism 11 Bracket 12 Head unit transfer slider 13 Head unit transfer guide rail 14 Head unit transfer linear motor 15 Head unit transfer position detection means 16 Support 17 Plate 18 Stand 21 Alignment camera 22 Head unit base 23 Inkjet head part 30 Substrate transfer stage 32 Head unit 33 Head unit transfer stage 40 Inkjet printing device 100 Inkjet head control means 110 Storage means 120 Calculation means n ₁ First nozzle position n ₂ 2nd nozzle position n ₃ 3rd nozzle position n ₄ 4th nozzle position O Inkjet head rotation center P ₁ 1st nozzle discharge angle Landing position shifted due to habit P ₂ 2nd nozzle discharge angle a discharge angle habit of jetting angle landing position misaligned by habit P 4 ₄ th landing position misaligned by jetting angle habit of nozzle Q 1 ₁ th nozzle of landing position P 3 ₃ th nozzle misaligned by habit Landing position misaligned due to running Q ₂ Discharge angle habit of the second nozzle and landing position misaligned due to running Q ₃ Discharge angle habit of the third nozzle and landing position misaligned due to running Q ₄ 4th nozzle Discharge angle Landing position shifted due to habit and running W ₀ Coating area pitch W ₁ Coating area pitch W ₂ Coating area pitch

Claims (7)

An inkjet printing method in which droplets are ejected from the inkjet head while scanning the inkjet head relative to the object to be coated, and ink is applied onto the object to be coated.
A memory that stores the landing position deviation characteristic obtained based on the landing position deviation of the droplet ejected from the inkjet head from the target position when the inkjet heads have different first and second rotation angles. The first step of reading the data related to the landing position deviation characteristic from the means, and
The target rotation angle of the inkjet head is obtained based on the landing position shift characteristic, the arrangement pitch of the droplet ejection nozzles of the inkjet head, and the coating target pitch of the coating object in the direction orthogonal to the scanning direction. At the same time, a second step of generating a print pattern corresponding to the target rotation angle, and
A third step of controlling the inkjet head based on the target rotation angle and the printing pattern to eject droplets to the coating target portion on the coating object.
Inkjet printing method having. The landing position shift characteristic includes the landing position shift amount due to the ejection angle habit of the droplet discharge nozzle of the inkjet head and the landing position shift amount due to scanning of the inkjet head.
The inkjet printing method according to claim 1. Further, a fourth step of calculating an offset amount in a direction orthogonal to the scanning direction of the inkjet head for aligning the inkjet head with the coating target portion when the inkjet head is at the target rotation angle is further performed. In the third step, the inkjet head is controlled to eject droplets to the coating target portion based on the target rotation angle, the printing pattern, and the offset amount.
The inkjet printing method according to claim 1 or 2. The landing position shift characteristic is obtained by the following steps A to E and is stored in the storage means.
A) A step of positioning the inkjet head at the first rotation angle with the normal direction of the surface of the object to be coated as the rotation axis, and ejecting droplets in the first printing pattern.
B) The step of detecting the landing position deviation of the droplets ejected in the step A) from the target position indicated by the first printing pattern.
C) A step of positioning the inkjet head at the second rotation angle and ejecting droplets in the second printing pattern.
D) A step of detecting a deviation of the landing position of the droplet ejected in the step C) from the target position indicated by the second printing pattern.
E) The step of calculating the landing position deviation characteristic based on the landing position deviation detected in the step B), the landing position deviation detected in the step D), and the coordinates of the rotation axis of the inkjet head. ,
The inkjet printing method according to any one of claims 1 to 3. In the third step, the relative moving speed of the inkjet head and the coating object is the relative moving speed of the inkjet head and the coating object in the step A), and the inkjet in the step C). Droplets are ejected from the inkjet head to the coating target portion under conditions that are the same as the relative moving speed of the head and the coating object.
The inkjet printing method according to claim 4. An inkjet printing device that ejects droplets from the inkjet head while scanning the inkjet head relative to the object to be coated to apply ink onto the object to be coated.
A memory that stores the landing position deviation characteristic obtained based on the landing position deviation of the droplet ejected from the inkjet head from the target position when the inkjet heads have different first and second rotation angles. Means and
The target rotation angle of the inkjet head is obtained based on the landing position shift characteristic, the arrangement pitch of the droplet ejection nozzles of the inkjet head, and the coating target pitch of the coating object in the direction orthogonal to the scanning direction. At the same time, a calculation means for generating a print pattern corresponding to the target rotation angle, and
With
An inkjet printing apparatus that controls the inkjet head based on the target rotation angle and the printing pattern to eject droplets onto a coating target portion on the coating object. A substrate adsorption table on which a substrate corresponding to the object to be coated is placed, and
A substrate rotation mechanism that rotatably supports the lower part of the substrate suction table,
A substrate transfer stage on which the substrate rotation mechanism and the substrate suction table are transferred, and
A substrate transfer position detecting means for detecting a substrate transfer position of the substrate transfer stage,
With the inkjet head arranged on the upper part of the substrate so as to face the substrate,
A head rotation mechanism that is arranged above the inkjet head and rotatably supports the inkjet head about the normal direction with respect to the plane of the substrate.
A head transfer stage for transferring the inkjet head and the head rotation mechanism in a direction orthogonal to the transfer direction of the substrate transfer stage and the direction of the rotation axis.
The inkjet printing apparatus according to claim 6.

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