HK1172292B - Ink-jet filming method - Google Patents

Description

Ink-jet film forming method

The present application is a divisional application of the chinese patent application having an application number of 200880005764.2, an application date of 2008, 2/21, entitled "cleaning method for inkjet coating apparatus".

Technical Field

The present invention relates to a cleaning method, a nozzle inspection method, a coating control method, and a film forming method for an inkjet coating apparatus including an inkjet recording head (hereinafter referred to as an "inkjet head"), and more particularly, to a cleaning method, a nozzle inspection method, a coating control method, and a film forming method for removing dirt, debris, impurities, and the like adhering to a nozzle surface of an inkjet head and its periphery.

The inkjet head in the present specification is not particularly limited, and is an inkjet head including a single or multiple nozzles.

Background

In an ink jet recording apparatus, in order to maintain high quality recording quality, it is necessary to remove ink, foreign matter, and the like remaining on an ink discharge surface of an ink jet recording head.

Patent document 1 discloses a method of cleaning an ink discharge surface of a head by wiping the ink discharge surface with a wiper blade, and the material, angle, contact type, and the like of the wiper blade are examined to improve cleaning performance.

Patent document 2 discloses a method in which an ink absorbing slit is provided on the downstream side of the ejection port in the return operation direction of the blade cleaning, and the ink scraped by the blade is sucked by an ink absorbing slit having a slit-shaped suction port provided parallel to the plurality of ejection ports, thereby improving the performance.

Patent document 3 discloses that after cleaning of the nozzle surface is performed by blowing the cleaning liquid from the nozzle of the atomizer toward the nozzle of the inkjet head and the periphery thereof, the cleaning liquid adhering to the nozzle of the inkjet head and the periphery thereof is scraped off by a scraper.

Patent document 4 discloses a method for discharging droplets of an alignment film, in which an ink jet head having a plurality of nozzles arranged at a predetermined pitch is moved relative to a substrate, and the droplets of the alignment film are discharged from the nozzles onto the substrate, wherein the direction in which the ink jet head is moved relative to the substrate is inclined at a predetermined angle with respect to the direction in which pixels constituting a lattice shape in the substrate are arranged.

Patent document 5 discloses a thin film forming apparatus including: a head support structure having a plurality of nozzles arranged at a predetermined interval and having one or more inkjet heads; and a substrate carrying mechanism having a substrate carrying platform capable of relatively moving between the plurality of nozzles in a direction orthogonal to the direction in which the plurality of nozzles are arranged; a non-contact thin film forming apparatus for spraying a thin film forming solution from the plurality of nozzles onto a surface of the substrate mounted on the substrate transfer table to apply the solution and form a thin film; it is characterized by comprising the following components: at least the inner part is provided with the substrate conveying platform, an ink jet nozzle and a vacuum groove which is used as a spray coating film forming chamber and contains the nozzle supporting structure; and a pressure reducing means for reducing the pressure inside the vacuum chamber so that the film can be formed by spray coating in a reduced pressure environment.

Patent document 6 discloses an alignment layer forming method including: an inspection step of dropping the alignment film material in droplets by using an inkjet nozzle, and inspecting the inkjet nozzle for abnormalities by means of a pattern of the dropped droplets; and a film forming step of forming an alignment film by making the ink jet face the substrate and dropping the alignment film material as droplets onto the substrate using the ink jet nozzle when it is determined in the inspection step that the droplet pattern is within the predetermined range.

Patent document 7 discloses a method for manufacturing a device including a step of ejecting a liquid material from a liquid droplet ejection head to a pattern formation region of a substrate; it is characterized by comprising the following steps: and a rinsing step of discharging the liquid material to a predetermined region other than the pattern forming region.

Patent document 1: japanese patent laid-open publication No. 2004-291364

Patent document 2: japanese patent laid-open publication No. 2004-42571

Patent document 3: japanese laid-open patent publication No. 2002-19132

Patent document 4: japanese patent laid-open publication No. 2006-320839

Patent document 5: japanese patent laid-open publication No. 2006 and 289355

Patent document 6: japanese patent laid-open publication No. 2006 and 058772

Patent document 7: japanese patent laid-open publication No. 2003-282245

Disclosure of Invention

(problems to be solved by the invention)

The present invention aims to provide a cleaning method, a nozzle inspection method, a coating control method, and a film forming method for an inkjet coating apparatus, which can solve the technical problems described below.

(means for solving the problems)

The invention of claim 1 is a method of cleaning an ink jet head, characterized in that a cleaning area of the ink jet head is covered with a unit member having a cleaning liquid supply port and a suction port, and cleaning liquid is ejected from the cleaning liquid supply port facing the suction port toward the cleaning area by suction force applied from the suction port.

The invention according to claim 2 is the invention according to claim 1, wherein after the cleaning, the cleaning region of the inkjet head is dried by applying a suction force to the unit member while slightly separating the inkjet head from the unit member.

The invention according to claim 3 is the cleaning liquid according to claim 1 or 2, wherein the cleaning liquid is a liquid composed of a solvent having a factor for dissolving the liquid material.

The invention 4 is a method for inspecting an ink jet head, in which a liquid material ejected from a nozzle of the ink jet head is dropped onto an inspection member, and abnormality of the nozzle is inspected based on a pattern of the dropped liquid droplet; the method for inspecting an inkjet head is characterized in that the member for inspection is made of a material having a reflectance different between a place where the liquid material is dropped and a place where the liquid material is not dropped.

The 5 th aspect of the present invention is the 4 th aspect of the present invention, wherein the inspection member is a thin film that is dissolved by dropping of the liquid material.

The invention according to claim 6 is an ink jet application control method in which, after a discharge operation from an ink jet head, a discharge liquid material filled in a flow path in the ink jet head is replaced with a low volatility replacement material, and immediately before the start of the discharge operation, the replacement material is replaced with the discharge liquid material again.

The 7 th invention is the invention according to the 6 th invention, wherein the alternative material is a liquid composed of a solvent having a factor for dissolving the liquid material.

The invention 8 is an ink-jet film forming method for forming a film by a plurality of ejection steps; the method is characterized in that after the droplets on the workpiece ejected in the previous step are dried to a degree that they do not flow, the liquid material is ejected to a position where it contacts or partially overlaps the droplets of the liquid material ejected in the previous step.

The 9 th invention is the 8 th invention, wherein the number of injection steps is increased and the injection amount per one injection is decreased.

The 10 th invention is the 8 th or 9 th invention, wherein the wiring pattern is formed of a film.

(effect of the invention)

(1) In cleaning the inkjet head, since a solid object such as a blade does not contact the nozzle of the inkjet head and the periphery thereof, the inkjet head can be cleaned without generating abrasion dust.

Further, since the cleaning liquid is used, the cleaning can be performed with a strong cleaning power even when the liquid material such as ink is dried.

In addition, the method has the characteristics of shortening the operation time and being capable of being manufactured at low cost.

(2) The defective nozzle of the ink jet head can be detected with high visibility, and the visibility can be improved remarkably particularly for a transparent liquid material.

(3) The problem of coating control of an ink jet head is solved, and stable discharge operation can be performed. Especially has higher effect on high-volatility liquid materials.

(4) In the film formation by ink jet, the thickness difference of the whole surface can be reduced compared with the conventional method.

Drawings

Fig. 1a is a schematic plan view of the entire apparatus including the cleaning mechanism of example 1.

Fig. 1b is a schematic side view of the entire apparatus including the cleaning mechanism of example 1.

Fig. 2 is a schematic explanatory view showing one mode of the cleaning mechanism of embodiment 1.

Fig. 3 is a schematic configuration diagram showing another mode of the cleaning mechanism of embodiment 1.

Fig. 4a is a plan view showing the structure of the washing unit of example 1.

Fig. 4b is a side sectional view showing a schematic structure of the washing unit of example 1.

FIG. 5 is a diagram illustrating a cleaning step and a drying step performed by the cleaning unit of example 1.

Fig. 6 is a flowchart of the cleaning and drying steps of the inkjet head according to example 1.

Fig. 7 is an explanatory diagram of a nozzle inspection mechanism according to embodiment 1.

Fig. 8 is a flowchart showing a procedure of applying control by the inkjet head.

Fig. 9 is a conceptual schematic structural view for explaining the operation of the ink jet head.

Fig. 10 is a diagram illustrating a pretreatment operation of the ink jet head in the structure of fig. 9.

Fig. 11 is an explanatory diagram of the post-processing operation of the ink jet head in the structure of fig. 9.

Fig. 12 is a diagram illustrating a comparison between a conventional method for forming a thick film and a method for forming a thick film according to the present invention.

Fig. 13 shows a wiring pattern that can be formed by the film formation method of the present invention.

Fig. 14 is a structural diagram of a maintenance mechanism according to embodiment 2.

Fig. 15 is a side view showing a suction/irrigation unit of the perspective embodiment 2.

Fig. 16 is a signal waveform outputted from the machine of embodiment 2.

Description of the symbols

2 liquid material

3 cleaning liquid

4 used cleaning solution (waste liquid)

5 negative pressure

6 nozzle

7 opening and closing mechanism

8 Signal generating device

9 communicating member

10 ink jet head

11 liquid material discharge surface

12a, 12b liquid material bottle

13 liquid detergent bottle

14 workpiece platform

15 Personal Computer (PC)

16 operating table

19 pressure supply pump

20 washing unit

21 liquid receiving part

22 discharge valve

23 cleaning lip

24 bottom suction port

25 cleaning solution supply port

26 cleaning liquid recovery port

28 opening

31a, 31b cleaning solution nozzle electromagnetic valve

32a, 32b side nozzle atmosphere opening valve

33 supply valve

34a, 34b negative pressure solenoid valve

35 cleaning liquid supply valve

36 material switching valve

37 ejector

38 adjuster

40 waste liquid tank

41 hand joint

51 open/close electromagnetic valve

52 full sensor

61 abutting member

62 frame

63 support member

64 mounting member

66 joints

71 formal liquid

72 film for inspection

73 plate

74 image pickup device

75 reflective lighting

76 penetration illumination

77 field of view of the image pick-up device

78 dropping of the final liquid

81 feed roller

82 take up roller

101 ink jet head control box

102 suction/flushing unit

103 head cover unit

104 image camera

105 liquid material switching unit

106 ink jet control substrate

107 liquid material tank

108 emergency stop switch

109 base plate

110 crossbeam

112 various air compressor machines

113 Instrument box

114 control box

121X-axis moving mechanism

122Y-axis moving mechanism

123Z-axis moving mechanism

124 theta axis rotating mechanism

125H theta shaft rotating mechanism

151 first valve

152 second valve

Detailed Description

The present invention is based on the following four technical ideas relating to an inkjet coating apparatus.

(1) Cleaning method and mechanism

[i] Subject matter

The first technical idea is to improve the problem that the removal capability of droplets adhering to the ejection surface of an ink jet head is low.

In addition, because the size of the existing washing mechanism is large, the object of further miniaturization also belongs to the problem to be solved.

Also, the problem to be solved is that cleaning is not performed with a hard blade. The reason is that if the blade is brought into contact with the nozzle of the ink jet head or its peripheral portion, abrasion dust is generated. If abrasion dust is generated, it becomes a cause of clogging of the nozzle, and there is a problem that the surrounding environment is polluted. Further, if there is a possibility of generation of abrasion dust, it is necessary to use the dust-free indoor unit, which is limited.

[ ii ] substance

In order to remove the liquid material adhering to the ejection surface of the inkjet head, the adhering liquid material is brought into contact with a cleaning liquid (cleaning agent) for dissolving the liquid material, and the liquid material is effectively dissolved by the cleaning liquid.

Further, it is important to form an ejection port for ejecting the liquid material on the ejection surface so that the periphery of the ejection port is in contact with the cleaning liquid without any omission. An ink jet head having a plurality of ejection ports on an ejection surface is particularly important.

The first technical idea is that the cleaning liquid supplied from one end of the ejection surface of the ink jet head flows over the surface of the ejection surface and is collected from the end farthest from the end from which the cleaning liquid is supplied. The cleaning liquid is used to dissolve the liquid material attached to the injection surface from the end of the injection surface and to flow to the opposite end of the injection surface, thereby efficiently cleaning the injection surface without leakage.

Preferably, the cleaning liquid is supplied to the emission surface from a plurality of positions at one end of the emission surface, and the cleaning liquid is collected from a plurality of positions opposite to the one end. Here, the number of positions to which the cleaning liquid is supplied does not need to be the same as the number of positions to which the cleaning liquid is collected.

More preferably, the cleaning liquid is supplied from one end of the ejection surface of the inkjet head in the longitudinal direction, and the cleaning liquid is collected from the opposite end of the ejection surface in the longitudinal direction. The reason is that the flowing distance of the cleaning liquid on the ink jet ejection surface can be shortened, and the cleaning efficiency can be improved.

The ink jet head having a plurality of ejection openings is also effective for a unit having a large size.

Further, the cleaned exit surface is wetted with the cleaning liquid, but it is preferable to dry the exit surface in order to shorten the waiting time. The drying means of the cleaned emission surface is preferably natural drying or air-blow drying because the emission surface can be prevented from being contaminated.

As described above, if no liquid droplet adheres to the ejection surface of the ink jet head, the accuracy of the amount of liquid droplets ejected from the ink jet head and the accuracy of the position where the liquid droplets land on the workpiece are improved.

The cleaning liquid of a preferred embodiment is composed of a colorless solvent (e.g., a solvent of a main component that dissolves the ink) having a factor of dissolving the ink.

However, inks generally used in inkjet printers can be classified into dye-based or pigment-based. By "dye" is meant a colorant that is dispersed or solvated using a carrier medium as the molecule. The carrier medium is liquid or solid at room temperature. The carrier medium usually used is water or a mixture of water and an organic cosolvent. Generally, water is used as a main component, and a colorant and a wetting agent such as glycerin are contained therein for preventing clogging and the like. In the case of water as the carrier medium, the inks generally have the disadvantage of a low water fastness.

The term "pigment" refers to a colorant which is insoluble in a carrier medium, but is dispersed or suspended in the form of small particles and is stabilized by a dispersant so as not to cause aggregation or precipitation in ordinary use. Many of such compounds are known, and there are pigment inks and the like in which a pigment such as an organic pigment or carbon black is made into fine particles using a surfactant or a dispersant and is dispersed in a medium such as water to be used as a colorant.

The technical idea is applicable regardless of the dye system or the pigment system. The viscosity of the ink is mainly low on the order of several tens of cps, but the ink can be suitably used even at a medium viscosity on the order of several hundreds of cps or more, provided that the ink can be ejected in a scattering manner.

The present technical idea can also be applied to functional inks used for printing wiring patterns on a printed substrate, applying a lubricant to a micro component, printing outdoor light-resistant display materials, printing UV-curing inks, and the like.

[ iii ] order of implementation

The cleaning of the inkjet head is performed in the order of steps A to D (see FIG. 6). The "b cleaning operation" will be described by way of an example of the sequence of the structure shown in fig. 3.

(A. arrangement of ink jet head to cleaning mechanism)

The inkjet head 10 is brought into contact with a cleaning unit 20 of a cleaning mechanism. That is, the lower surface of the inkjet head 10 is brought into contact with the upper surface of the cleaning unit 20 so as to cover the liquid receiving portion 21 provided in a concave shape at the central portion of the cleaning unit 20. The cleaning lip 23(cleaner lip) serves as a contact surface between the lower surface of the inkjet head 10 and the upper surface of the cleaning unit 20.

(B. cleaning operation)

1) The cleaning liquid nozzle electromagnetic valves 31a and 31b are opened, and the cleaning liquid nozzle electromagnetic valves communicate with the flow paths connected through the electromagnetic valves 31a and 31 b.

2) The side nozzle atmosphere release valves 32a and 32b block communication with the atmosphere, and are located at positions in communication with the flow path connected thereto via the release valves 32a and 32 b. (the washing unit 20 is communicated with the electromagnetic valve 31a by the opening valve 32a, and the electromagnetic valve 31b is communicated with the drain valve 22 by the opening valve 32 b.)

3) The ejector 37 communicates with the liquid receiving portion 21 of the washing unit 20 via the drain valve 22, and the negative pressure solenoid valves 34a and 34b are opened.

4) By the steps up to 3), negative pressure is generated by the ejector 37 in the flow path of the washing unit 20, and the washing liquid stored in the washing liquid bottle 13 is supplied to the washing unit 20.

5) The cleaning liquid supplied to the cleaning unit 20 is supplied to the inkjet head 10 from a cleaning liquid supply port 25. The cleaning liquid supply port 25 is formed near the outer periphery of the lower surface of the inkjet head 10, and the cleaning liquid discharged from the cleaning liquid supply port 25 is efficiently supplied near the outer peripheral end of the lower surface of the inkjet head 10.

6) The cleaning liquid supplied to the lower surface of the ink jet head 10 flows under the ink jet head 10, and is collected again in the cleaning unit 20 from a cleaning liquid recovery port 26 formed in the vicinity of the opposite end to the cleaning liquid supply side of the lower surface of the ink jet head 10, or is separated from the lower surface of the ink jet head 10 before reaching the cleaning liquid recovery port 26 and is collected in a liquid receiving portion 21 of the cleaning unit 20. The liquid receiving portion 21 communicates with the drain valve 22, and the drain valve 22 is located at a position where communication with the liquid receiving portion 21 is blocked by another flow path through the drain valve 22, so that the cleaning liquid remains in the liquid receiving portion 21.

The cleaning liquid flowing into the cleaning unit 20 from the cleaning liquid recovery port 26 is recovered in the waste liquid tank 40 through the drain valve 22 and the ejector 37.

7) After the cleaning is sufficiently performed, the cleaning liquid nozzles 31a and 31b are closed, the solenoid valves 34a and 34b for negative pressure are closed, and the side nozzle atmosphere opening valves 32a and 32b are placed in a position where they communicate with the atmosphere. Thereby, the supply of the cleaning liquid to the cleaning unit 20 is stopped, and the pressure of the liquid receiving portion 21 is changed from the negative pressure to the atmospheric pressure.

(C. separation of ink jet head from cleaning mechanism)

The lower surface of the ink jet head 10 is separated from the upper surface of the cleaning unit 20, and a gap is formed between the lower surface of the ink jet head 10 and the upper surface of the cleaning unit 20. The gap is set to a distance that generates an appropriate air flow based on the subsequent drying operation to be performed.

(D. drying operation)

1) To communicate the waste liquid tank 40 with the washing unit 20, the drain valve 22 is switched to open the negative pressure solenoid valves 34a and 34 b.

2) Accordingly, the liquid receiving portion 21 of the cleaning unit 20 communicates with the waste liquid tank 40, and negative pressure acts on the liquid receiving portion 21, so that the cleaning liquid stored in the liquid receiving portion 21 flows toward the waste liquid tank 40, and the cleaning liquid as a waste liquid is collected by the waste liquid tank 40.

3) Further, a gap is provided between the lower surface of the inkjet head 10 and the upper surface of the cleaning unit 20, and the atmosphere that cancels the negative pressure of the liquid receiving portion 21 flows into the liquid receiving portion 21 from the gap. The atmospheric air flowing through the gap acts to drip the cleaning liquid adhering to the lower surface of the inkjet head 10, and the dripping cleaning liquid drips into the liquid receiving portion 21 and is collected by the waste liquid tank 40. In addition, the air flow (negative pressure) may also be adjusted by adjusting the distance between the lower surface of the inkjet head 10 and the cleaning unit 20.

4) After the cleaning liquid stored in the liquid receiving portion 21 is collected in the waste liquid tank 40, if this state is maintained, the air flowing through the gap acts to dry the lower surface of the inkjet head 10. Since the ejection port for ejecting the liquid material is formed in the lower surface of the inkjet head 10, the lower surface can be dried without being in contact with other substances, and therefore, the ejection port can be kept in an extremely clean state.

5) After the lower surface of the ink jet head 10 is sufficiently dried, the negative pressure solenoid valves 34a and 34b are operated to be positioned at the closed position, and the supply of the negative pressure to the liquid receiving portion 21 by the cleaning unit 20 is stopped.

6) Then, the supply valve 33 is actuated to connect the ink jet head 10 and the liquid material supply bottle 12, and the liquid material flow path is integrated into a state in which the liquid material can be supplied to the ink jet head 10.

[ iv ] Effect

According to the first technical idea described above, since the cleaning is performed by the cleaning liquid, abrasion dust is not generated.

Further, since the cleaning liquid is ejected by the action of the negative pressure, the cleaning liquid is not supplied if the ink jet head is not in close contact with the cleaning unit. Therefore, even if the ink jet head and the cleaning unit are separated from each other, the supply of the cleaning liquid can be stopped by the vacuum break, and the cleaning liquid can be prevented from being ejected to the outside of the cleaning unit.

In addition, since the drying operation is also performed by the negative pressure action, the outside of the cleaning unit can be prevented from being contaminated by the cleaning liquid.

(2) Nozzle inspection method and mechanism

[i] Subject matter

Since the conventional ink jet coating apparatus is of an ink jet type, there has been a problem that a necessary amount of droplets cannot be properly applied to a necessary portion due to a nozzle failure, a nozzle orientation, a nozzle clogging with a liquid material, and the like.

Further, as disclosed in patent document 6, in the inspection method performed by dropping a liquid material on an inspection film, since the shape of the droplet collapses before reaching the image recognition camera after dropping, even if the shape of the droplet is recognized by an image, the inspection cannot be performed accurately.

[ ii ] substance

A second technical idea is to perform nozzle inspection by dropping a liquid material onto an inspection member (droplet receiving material), as disclosed in patent document 6. This is different from patent document 6 in that: the liquid material (droplets) to be applied is not focused on, but the portion of the droplet-receiving material where the liquid material is applied is compared with other portions.

In the present invention, the drip-receiving material is preferably composed of a film for inspection having a soluble material. Thus, even in the case of a transparent liquid material having poor visibility, the drop of the liquid material is dissolved, and the inspection film is turbid (changes in transparency or becomes opaque). Therefore, the dripping position is highly visually recognized, and the dripping position can be easily detected. Particularly, the effect is more remarkable when a high-transparency liquid material is used.

The drop receiving object for the liquid material drop is appropriately selected in accordance with the liquid material to be ejected, and the important point is that the reflectance of the liquid material drop portion changes. If the drop of the object is dissolved, the reflectance is changed by diffuse reflection, so that the drop can be captured with high accuracy by image processing. The liquid material may be a combination of a liquid material and a droplet whose reflectance is changed by dropping, or the liquid material may be infiltrated into the droplet. The manner in which the liquid material penetrates into the droplet receiving material is particularly effective for a liquid material that does not contain a solvent as a main component, for example, a liquid material that contains water as a solvent.

Preferably, the drop-receiving material is dissolved (or permeated) rapidly at the moment the liquid material drops. The reason is that if the liquid material dropped on the object to be dropped is held for a long time, the diameter of the drop trace is enlarged. Preferably, a material that diffuses during dissolution is not used, but a drop that penetrates (or permeates) the material so as to penetrate below the drop is used. For example, a liquid material using toluene as a solvent, preferably a polystyrene-based film is used. Preferably, the thickness of the drip-receiving material is set so as not to be dissolved by the dripping of the liquid material to reach the back surface of the drip-receiving material.

The droplets are preferably transparent, but need not be, and may be colored. The emphasis is on the good discrimination between the dripping part and the non-dripping part. The drip-receiving material is of course composed of a single material, but the case where the surface is coated and a plurality of films are layered is also included.

For the liquid material recognition of the dripping of the drip-receiving object, an image pickup device such as a CCD camera, a laser sensor, or the like can be used.

The image processing is, for example, to capture the dripping position by performing edge extraction or binarization on the captured field image including the dripping position.

[ iii ] order of implementation

The nozzle inspection process will be described with reference to an example of the structure shown in fig. 7 (a).

1) The take-up roller 82 is rotated to position the new inspection film 72 below the inkjet head 10. Here, the inspection thin film 72 located below the inkjet head 10 is positioned by the plate 73, and the distance from the inkjet head 10 is accurately maintained.

2) The main liquid 71 is discharged from the ink jet head 10 and dropped onto the upper surface of the inspection film 72. The inspection film 72 is dissolved by the dripping, and a mark of the dripping is left.

3) The take-up roller 82 is rotated to position the dropping position of the inspection film 72 above the imaging device 74.

4) The inspection film 72 is imaged by an imaging device 74. The imaging by the imaging device 74 may be performed after the inspection film 72 is stopped, or may be performed in a state where the inspection film 72 is moved.

5) The state of the inkjet head 10 is checked based on the image data acquired by the imaging device 74. The clogging can be checked from the "drop-out" and "diameter" of the drop mark, and the scattering failure can be checked from the deviation of the drop position.

(3) Coating control method

[i] Subject matter

The course questions are: the ink jet head can prevent the nozzle from being blocked, thereby realizing stable ink discharge operation and having required precision.

When the liquid material discharge operation is stopped, the flow path near the discharge port of the ink jet head is dried, and there is a problem that the liquid material is clogged due to the thickening of the liquid material and the deposition of solid components from the liquid material, and the flying of the discharged liquid material is bent, so that the stable discharge operation cannot be performed.

Further, if the discharge stability of the liquid material is deteriorated, there is a problem that a product requiring a required precision cannot be manufactured, and in mass production, it is necessary to perform processing such as carrying out of a workpiece, carrying in/positioning of a next workpiece, and alignment processing from the discharge operation performed on one workpiece to the discharge operation performed on the next workpiece. In this period, the ink jet head must wait without performing the discharge operation, but the liquid material filled in the ink jet head is likely to be dried due to the waiting.

[ ii ] substance

The third technical idea is characterized in that: after the discharge operation, the discharge liquid material filled in the flow path in the inkjet head is replaced with a low volatility liquid material (replacement material), and the replacement material is replaced with the discharge liquid material again just before the discharge operation is started. Here, the substitute material is preferably a liquid having a dissolving action on the liquid material or a liquid having a washing action.

Preferably, a cleaning step of cleaning a lower surface of the inkjet head, which forms the ejection port for ejecting the liquid material, is added after the flow path in the inkjet head is filled with the refill.

The ink jet head having passed through the above-mentioned refill filling and cleaning step is free from the liquid material remaining, and is free from the fear of thickening the liquid material and the precipitation of solid components from the liquid material even during the waiting period of the discharge operation. Therefore, the occurrence of the problem can be completely excluded.

According to the present technical idea, even if the discharge operation is waited for a long time due to unexpected trouble or the like, deposition/solidification of solid components and clogging of the nozzle do not occur. Further, since the liquid material is filled in the inkjet head immediately before the discharge operation is performed, a fresh liquid material can be used for the workpiece.

[ iii ] order of implementation

The coating operation was performed in the following order. First, the head cap unit attached under the inkjet head is detached. The head cover unit is attached at the time of coating work waiting, in order to keep clean ejection openings formed under the ink jet head and prevent unnecessary evaporation of a fluid (replacement material) filled in a flow path in the ink jet head communicating with the ejection openings.

After the head cap unit is detached, the inkjet head is filled with the injected liquid material. The flow path in the ink jet head before the liquid material is filled with a fluid different from the liquid material called a replacement material. The replacement material, as previously described, preferably has the effect of dissolving the liquid material. In this way, the liquid material filling operation covers the ejection opening of the inkjet head with the suction/flushing unit, and after the replacement material in the inkjet head is sucked and discharged by applying negative pressure, the ink filling operation is performed by the same suction operation. That is, the maintenance method of the inkjet head is performed by covering the nozzles of the inkjet head with the unit member and generating negative pressure to suck the liquid; wherein is provided with: a waste liquid tank for communicating the unit member with the negative pressure generating mechanism; a low viscosity liquid storage portion communicating with the ink jet head; an ink storage portion communicating with the inkjet head; and a liquid switching mechanism for selectively communicating the ink jet head with the low viscosity liquid reservoir or the ink reservoir; the low viscosity liquid storage part is communicated with the ink jet head, the unit component generates negative pressure, the low viscosity liquid is filled in the ink jet head, the ink storage part is communicated with the ink jet head, and the ink jet head is filled with ink.

After filling the inkjet head with the ejection liquid material, the liquid material is ejected at a predetermined position other than the workpiece, and whether or not the ejection is performed is checked (pseudo-ejection operation). In particular, when the inkjet head is provided with a plurality of ejection ports, it is necessary to check whether or not the liquid material is ejected from all the ejection ports. In this confirmation operation, when the liquid material is not ejected from all the ejection openings, all the liquid material filled in the ink jet head is ejected and refilled. The method is performed by replacing the replacement material with the liquid material.

After the refilling, the dummy ejection operation is performed again, and whether or not the liquid material is ejected from all the ejection ports is checked. If it is confirmed that the liquid material is ejected from all the ejection ports, the ink jet head and the stage on which the workpiece is placed are moved relative to each other, and the ink jet head is disposed at a coating position on the workpiece to perform a coating operation.

If the predetermined coating operation is completed, the workpiece is discharged into a workpiece storage device known as an unloader. While the workpiece discharge is being performed, the liquid material filled in the flow path in the ink jet is discharged to the ink jet head in accordance with the above-described procedure, and the operation of filling the replacement material is performed. By this operation, the liquid material in the flow path of the inkjet head is replaced with the replacement material. If the liquid material is dissolved in the substitute material, the liquid material is dissolved in the filled substitute material even if the liquid material remains slightly in the flow path, and therefore the liquid material is not solidified in the flow path of the inkjet head.

The flow path in the ink jet head is statically dissolved and cleaned in place of the filling of the material. After the filling operation of the replacement material is completed, the lower surface of the inkjet head is cleaned. Preferably, the cleaning is performed by the method using the cleaning liquid described in the first technical idea. When the cleaning of the nozzles is completed, the inside and the outside of the inkjet head are cleaned, and the inkjet head is kept clean without the liquid material adhering thereto.

After the cleaning has been completed, the head cover unit is attached under the nozzle unit, thereby preventing volatilization of the replacement material. The above steps are repeatedly performed for each workpiece.

(4) Film forming method

[i] Subject matter

The conventional film formation method using ink jet has the following two problems. One is a problem in the height direction (film thickness) and the other is a problem in the horizontal direction. The former is a problem that a uniform film thickness cannot be formed due to a coffee stain phenomenon (coffee stain) that forms ridges around the edges of the film forming surface. The latter is a problem that a scattering occurs at the end (edge) of the film formation surface, and a clear edge line cannot be formed.

Patent document 4 discloses: in order to solve the problem that the thickness of the alignment film is not uniform due to the connection of the droplets, the substrate is inclined at a predetermined angle, but the problem of non-uniform film thickness has not been completely solved.

In addition, the coffee stain phenomenon occurs in a low viscosity solution, and is a fatal problem of an alignment film of a liquid crystal display device. In the case of the alignment film, since polyimide, which is a main component, is less soluble, a large amount of gamma-butyrolactone, N-methylpyrrolidone, butylcellosolve, or the like, which is a dissolving material, is used, and spray coating is performed at a low viscosity, so that a coffee stain phenomenon is likely to occur.

[ ii ] substance

The inventors have found that if the coating is performed so that the liquid does not flow, the film can be formed with a uniform film thickness as a whole; and found that if a plurality of droplets discharged from the ink jet head and landed on the surface of the workpiece are combined with each other, the edge line will leak, thereby creating a fourth technical idea.

The fourth technical idea is characterized in that: after the liquid droplets are ejected onto the workpiece by the first ejection operation of the inkjet head, when the liquid droplets are ejected at a contact position or an overlapping position, the ejection is performed after waiting until the liquid droplets on the workpiece are in a dry state (including a semi-dry state in which the movement of the substance is stopped) in which the liquid droplets do not flow.

As described above, if the first droplet ejected onto the workpiece is dried by the first ejection operation and then ejected onto the contact position or the overlapping position of the first droplet after the second ejection operation, the droplets after the second ejection operation are not yet fluidically combined with each other on the workpiece. That is, since the droplets (first droplets) ejected by the first ejection operation are in a dry state, fluid coalescence in which the droplets (second droplets) ejected after the second ejection operation are in contact with each other and are formed into one droplet by coalescence does not occur.

On the other hand, when the first droplet and the second droplet are fluidically combined as in the conventional case, since the coffee stain phenomenon occurs more remarkably, the film thickness of the edge portion of the film is thickened compared to the film thickness of the center portion. That is, the difference in thickness between the droplet center film thickness and the droplet edge film thickness formed by the droplet-to-droplet combination becomes larger than the difference in thickness between the droplet center film thickness and the droplet edge film thickness before the combination. However, in the case where the droplets are combined and form a single droplet, since a high degree of homogenization is formed due to the flow of the liquid material, it is impossible to visually recognize the contact area or the overlapping area after the combination.

In this respect, in the present technical idea, since the film is dried and formed at each injection operation, the difference in the overall thickness of the surface can be reduced as compared with the conventional method of generating fluid coupling.

FIG. 12 is a diagram comparing a conventional injection method with the method of the present invention in film formation. In fig. 12, the upper diagram (a) shows a conventional method in which liquid materials discharged onto a workpiece are combined to be the same, and the lower diagram (b) shows a specific film forming method example in which each droplet of a first droplet group discharged by a first discharge is arranged on the workpiece so as to be separated from another adjacent droplet and then discharged so as to bury a gap between the droplets. In the lower diagram (b), the second ejection is performed to the right with respect to the ejection position of the first droplet group, the third ejection is performed to the lower side with respect to the ejection position of the first droplet group, and the fourth ejection is performed to the right obliquely lower side with respect to the ejection position of the first droplet group. Here, it is needless to say that in the second ejection, the third ejection, and the ejection after the fourth ejection, the ejection in the next step is performed after drying to a degree that the flow of the droplets formed by the ejection in the previous step is suppressed.

It is to be understood that the present technical idea is not limited to the order of the injection positions illustrated in fig. 12. The injection position may be a regular injection position where the entire surface of the workpiece is uniformly coated by a plurality of injection steps (injection steps). Thus, the number of injection steps may be three or less, or five or more. If the number of injection steps is increased and the amount of coating per single injection step is reduced, the unevenness of the workpiece surface can be reduced. The reason is that the unevenness of the workpiece surface has a correlation with the coating amount. Further, if the amount of coating is reduced, the drying time can be shortened.

In the case where the ink jet unit has a plurality of ejection ports, the droplets (first droplet group) ejected by the first ejection operation are dropped onto the workpiece at positions separated from each other, and the droplets do not come into contact with each other. In this case, the plurality of droplets (second droplet group) ejected in the second ejection operation are performed after the first droplet group is dried to such an extent that the droplets do not flow, and the same effect can be obtained.

The droplet drying on the workpiece may be natural drying, but drying can be performed more quickly by raising the temperature of the stage on which the workpiece is placed.

The temperature for drying the droplets is appropriately adjusted according to the conditions such as the type of the liquid material, the pitch, and the amount of the injected liquid material, and is set to a temperature ranging from the experimental environment temperature (for example, 15 to 25 ℃) to 150 ℃, preferably ranging from the experimental environment temperature to 100 ℃, and more preferably ranging from the experimental environment temperature to 50 ℃.

The drying time for drying the droplets to such an extent that the droplets do not flow is also appropriately adjusted depending on the conditions such as the stage temperature, the type of liquid material, the pitch, and the amount of ejection, and is preferably set to about 20 to 100 seconds from the dropping.

The film forming method of the present invention as described above can reduce the amount of bleeding out of the edge portion as compared with the conventional film forming method, and therefore can be suitably used for various applications such as formation of an alignment film of a liquid crystal display device. The film forming method of the present invention is also applicable to the formation of fine wiring patterns on a substrate as shown in FIG. 13. That is, although the conventional film forming method cannot form a fine pattern at a high density because a large amount of bleeding may cause interconnection between wirings, the film forming method of the present invention can form fine wirings at a high density. The reason is that the film forming method of the present invention can greatly reduce the amount of diffusion in the lateral direction (horizontal direction) (in example 3 described later, the amount of diffusion is about 1/10 of the conventional film forming method). The film forming method of the present invention is particularly suitable for forming a thin film having a film thickness of several nm to several tens μm.

In addition, the film forming method of the present invention can easily control the film thickness. In the conventional film forming method, the liquid material after the dropping is combined with the liquid material ejected next time to form uniform droplets, and the uniform droplets are spread in the lateral direction (horizontal direction), so that it is difficult to control the film thickness. In this regard, the film forming method of the present invention is to eject the next liquid material to the liquid material which is in a non-flowing state after dropping and stack the liquid material, thereby increasing the film thickness, so that the film thickness can be easily controlled by controlling the number of times of stacking.

The present invention will be described in detail below with reference to examples, but the present invention is not limited to the examples.

[ example 1]

The cleaning mechanism of the present embodiment includes a cleaning unit 2, and the cleaning unit 2 has a function of ejecting a cleaning liquid 12 to the inkjet head 1 and a function of ejecting air.

Fig. 1a is a schematic plan view showing the whole of the apparatus including the washing mechanism of the present embodiment, and fig. 1b is a schematic side view showing the whole of the apparatus.

The apparatus of this embodiment is an ink jet coating apparatus that performs coating while relatively moving an ink jet head 10 and a work table 14 located therebelow.

The inkjet head 10 is attached to the beam 110 via the Z-axis moving mechanism 123 and the H θ -axis rotating mechanism 125.

The workpiece stage 14 is a vacuum chucking type workpiece stage. A thermal manipulator may also be attached to the work piece platform 14.

The operation control such as the relative movement of the inkjet head 10 and the work table 14 and the cleaning of the inkjet head 10 can be executed by a Personal Computer (PC)15 on an operation table 16 provided near the coating apparatus.

FIG. 2 is a schematic explanatory view showing one mode of the cleaning mechanism of the present embodiment.

In fig. 2, reference numeral 42 denotes compressed air from CDA (clean dry air), reference numeral 43 denotes a CDA suction port opening/closing ball valve, reference numeral 44 denotes an exhaust air opening/closing ball valve, and reference numeral 45 denotes an exhaust filter (manipulator).

FIG. 3 is a schematic configuration diagram showing another embodiment of the cleaning mechanism of the present embodiment.

The cleaning unit 20 is used to prevent the cleaning liquid from scattering on peripheral parts when the inkjet head 10 is cleaned. The cleaning unit 20 has an open box shape or the like that covers the nozzle surface of the inkjet head 10 and the periphery thereof from below. The cleaning unit 20 is made of, for example, stainless steel or teflon (registered trademark) because it is necessary to use a material that takes into consideration chemical resistance of the cleaning liquid or the like.

The cleaning liquid is used for completely washing off the ink adhering to the nozzle surface and the periphery of the inkjet head 10, and therefore a colorless solvent (a solvent that is a main component for dissolving the ink) having a factor for dissolving the ink is used.

Fig. 4a is a plan view showing the structure of the washing unit 20, and fig. 4b is a side sectional view showing the schematic structure of the washing unit 20.

The cleaning unit 20 has an opening 28 provided at the center of a cleaning lip 23 abutting on the inkjet head 10, and has a plurality of cleaning liquid supply ports 25 and a plurality of cleaning liquid recovery ports 26 provided at the edge of the long side so as to face each other.

Fig. 5 (a) is an explanatory view at the time of cleaning. As shown in the figure, the cleaning unit 20 is brought into contact with the inkjet head 10, and cleaning liquid is ejected from the cleaning liquid supply port 25 toward the vicinity of the outer peripheral end of the lower surface of the inkjet head 10 and is collected from the cleaning liquid collection port 26 and the liquid receiving portion 21, thereby cleaning.

Fig. 5 (b) is an explanatory view during drying. As shown in the figure, after the cleaning is completed, the inkjet head 10 and the cleaning unit 20 are separated slightly (for example, by 3mm), and the cleaning liquid adhering to the inkjet head 10 is blown off by the air flowing through the gap, thereby drying the inkjet head 10 and the cleaning unit 20. The washing unit 20 is provided with a bottom suction port 24, and the suctioned waste liquid is stored in a waste liquid tank 40.

Fig. 6 shows a flowchart of the cleaning step and the drying step of the inkjet head 10 according to the present embodiment.

However, when a negative pressure is generated in the cleaning unit 20, the adhesion between the lower surface (head surface) of the inkjet head 10 and the cleaning unit 20 is important. Here, if the inclination of the cleaning unit 20 with respect to the head surface is large, there is a problem that a gap is generated. Therefore, in the present embodiment, the structure that can track the inclination of the head surface ensures the close contact and sealing of the washing unit 20. That is, by forming the support member for supporting the cleaning unit 20 with a soft elastic body, the degree of freedom for tracking the inclination of the head surface is provided, and the sealing property can be maintained.

The cleaning unit 20 is provided with an opening/closing mechanism that is brought into contact with or not brought into contact with the inkjet head 10. The opening/closing mechanism can be configured by using a manual type, a ball screw type, a linear type, or other moving platform for lifting, and for example, a known moving platform manufacturer is available from jun river machines corporation and THK corporation.

(nozzle checking mechanism)

The nozzle inspection mechanism of the present embodiment is configured as shown in fig. 7.

First, the inkjet head 10 is moved toward an inspection area where an inspection thin film is disposed. In the inspection area, the state of each ink jet nozzle of the ink jet head 10 is inspected.

In the inspection area, a transparent inspection film 72 that moves so as to traverse the lower side of the inkjet head 10 is provided. The inspection film 72 is a film having solubility in the positive type liquid 71. The inspection film 72 is wound up in a roll form by a feed roller, and a new inspection film 72 can be used for inspection at all times by winding up the inspection film by a take-up roller.

The image pickup device 74 picks up an image of the droplet dropped from the inkjet head 10. The imaging device 74 may be constituted by a generally-available CCD camera or the like. Fig. 7 (a) shows a mode in which the imaging device is configured by two image recognition cameras (area sensors), and fig. 7 (b) shows a mode in which the imaging device 74 is configured by a line sensor. In fig. 7 (b), the visibility is improved by using the reflected illumination 75 and the transmitted illumination 76 in combination. The method is a matter of design, and is determined based on factors such as the width of the inspection film 72 and the detection accuracy.

In the inspection film 72, when there is no drop of the main liquid 71 or when the drop position is deviated from a predetermined position, the nozzle inspection means recognizes that a failure such as nozzle clogging has occurred and displays an error message.

Fig. 9 is a simplified conceptual configuration diagram showing an explanation of the operation of the inkjet head 10. As shown in fig. 9, the inkjet head 10 can selectively communicate the main liquid (the ejected liquid material) and the cleaning liquid via the liquid material switching unit 105.

Three units are arranged on the inner side of the side surface of the workpiece platform. In fig. 9, three units are arranged, that is, a suction/flushing unit 102 for generating a negative pressure for replacing the liquid material with the replacement material, a cleaning unit 20 for cleaning the lower surface of the nozzle, and a head cap unit 103 for capping the lower surface of the nozzle, in this order from the left side to the right side.

Fig. 10 is an explanatory diagram of a preprocessing operation of the ink jet head 10 having the structure of fig. 9. The description is made with respect to the six partial diagrams shown in fig. 10. In the switching unit 105, the solid line indicates the on state, and the broken line indicates the off state.

[10-1] shows a state in which a head cover unit 103 is attached to the lower surface of the inkjet head 10 and is communicated with a cleaning solution by a switching unit. Belongs to the state of waiting for coating operation.

[10-2] shows a state where the head cover unit 103 is detached from the inkjet head 10 during the coating operation. The switching unit 105 is located at a position where the inkjet head 10 communicates with the cleaning liquid.

[10-3] shows a diagram of a state in which the inkjet head 10 is set in the suction/flushing unit 102.

[10-4] after the ink jet head 10 is set in the suction/flushing unit 102, the switching unit 105 is used to switch the position where the liquid material communicates with the ink jet head 10. Then, a negative pressure is applied to the suction/flushing unit 102, whereby a liquid replacement operation (filling operation) in the inkjet head 10 is performed.

[10-5] shows a diagram in which after filling the liquid material in the flow path of the inkjet head 10, a dummy ejection operation is performed on the suction/flushing unit 102. The dummy ejection is a preliminary flowing operation performed before a main ejection operation is performed on the liquid material in the flow path of the inkjet head 10, instead of checking whether or not the liquid material is actually ejected from the inkjet head 10 by using an imaging device or a sensing device, for example. When the check operation for checking the nozzle is performed, it is preferable to perform the preliminary flow operation in advance. Of course, the check of the injection in the work may also be accompanied by a preliminary flow work.

[10-6] shows a state where the coating operation is performed while the inkjet head 10 is moved.

Fig. 11 is an explanatory diagram of the post-processing operation of the ink jet head 10 having the structure of fig. 9. The description will be made with respect to six partial diagrams shown in fig. 11.

[11-1] shows a diagram of a state where the inkjet head 10 is moved onto the suction/flushing unit 102 after the end of the job to be coated.

[11-2] shows a state where the ink jet head 10 is set in the suction/flushing unit 102 and the liquid material switching unit 105 is switched to a position where the ink jet head 10 communicates with the cleaning liquid.

[11-3] shows a state where the ink jet head 10 is detached from the suction/flushing unit 102 after the liquid replacement operation in the ink jet head 10 is finished.

[11-4] shows a cleaning operation performed by installing the inkjet head 10 in the cleaning unit 20. The liquid material switching unit 105 is held at a position where the inkjet head 10 communicates with the cleaning liquid.

[11-5] shows a diagram in which the inkjet head 10 is moved onto the head cover unit 103 after the cleaning step.

[11-6] shows a view in which a head cover unit 103 is attached under the inkjet head 10. By the attachment of the head cap unit 103, the ejection port is kept clean, and unnecessary evaporation of the replacement material filled in the flow path in the inkjet head 10 can be prevented.

[ example 2]

Fig. 14 is a structural diagram of a maintenance mechanism of the inkjet application apparatus according to the present embodiment.

The ink jet head 10 has a plurality of nozzles 6, and discharges the ink 2 stored in the first tank 12 communicated with each other by the communicating member 9 to perform printing or the like. The maintenance of the inkjet head 10 is to cover the nozzles 6 with the suction/flushing unit 102, and to generate negative pressure in the suction/flushing unit 102, and to discharge the sucked ink or the like into the waste liquid tank 40 communicated with the suction/flushing unit 102 by the communicating member 9. The contact between the suction/flushing unit 102 and the inkjet head 10 is automatically performed by the opening/closing mechanism 7. The opening/closing mechanism 7 may relatively move the inkjet head 10 or may relatively move the suction/flushing unit 102. In addition, the suction/flushing unit 102 may be opened and closed manually according to the industrial field.

The maintenance mechanism of the present embodiment is added to the conventional structure described above, and includes a second tank 13 communicating with the ink jet head 10 by the communication member 9, and a liquid switching unit 105 for alternatively switching communication between the ink jet head 10 and the first tank 12 or the second tank 13. The second tank 13 stores therein the cleaning liquid 3 of a low-viscosity liquid which flows in first at the time of starting maintenance. In this example, a solvent for dissolving the ink 2 was used as the cleaning liquid 3. Thereby, even if the ink 2 is solidified in the flow path, it can be dissolved.

In addition, as shown in fig. 15, the suction/flushing unit 102 of the present embodiment is configured to have a degree of freedom that can track the inclination of the head face.

The contact member 21, which contacts the head surface, is made of a rubber having a Shore A hardness of 40 to 80 degrees (preferably 50 to 70 degrees) (JIS K6253 standard) of a hardened elastomer, and is attached to the upper surface of the frame 62 by bonding, screwing, or the like.

The frame 62 is supported by a support member 63 which is fixed by bonding, screwing, or the like and is constituted by a soft elastic member (for example, rubber or a spring). The supporting member 63 can also penetrate as deep as 40 to 80 degrees (preferably 50 to 70 degrees) in order to track the mounting error (three-dimensional inclination) of the nozzle surface of the inkjet head 1. The support member 63 is fixed to the plate-like mounting member 64. A bottom suction port 24, which is at least one or more suction through-holes, and a joint 66 connected to the communication member 9 are disposed on the bottom surface of the frame 62.

According to the suction/flushing unit 102 of the present embodiment configured as described above, complete adhesion and sealing can be ensured without being affected by inclination of the nozzle surface.

The negative pressure generating mechanism of the present embodiment is constituted by the signal generating device 8, the pressure supply pump 19, the regulator 38, and the ejector 37, and is communicated with the suction/flushing unit 102 via the waste liquid tank 40. In addition, a silencer capable of absorbing air noise can be added to the negative pressure generating mechanism.

The signal generating device 8 can set and register a plurality of pattern times and voltage signal waveforms, and select and output only one pattern from the plurality of registered patterns. The regulator 38 may perform pressure supply in response to the signal waveform voltage of the signal generating device 8. The signal generating means 8 may also be constituted by, for example, a pulse generator, a PC, or the like.

The ejector 37 may generate a negative pressure corresponding to the pressure supplied from the regulator 38. The regulator 38 and the ejector 37 may be constituted by a commercially available air compressor machine.

Even if the negative pressure generated by the regulator 38 and the ejector 37 is not controlled, the negative pressure may be controlled by adjusting the throttle amount of a throttle valve provided on the waste side of the ejector 37 while maintaining a constant pressure from the regulator 38.

The negative pressure generating mechanism of the present embodiment is characterized by gently returning the negative pressure generated in the suction/flushing unit 102 to the atmospheric pressure. That is, the present embodiment gently varies the negative pressure in the suction/flushing unit 102 by the signal generating device 8 that issues a preset signal waveform, whereby re-mixing of air bubbles can be prevented.

The set signal waveform may be a signal waveform that changes linearly, curvilinearly, or finely in stages, on the premise that the negative pressure in the suction/flushing unit 102 changes gently. The curved waveform is a Sin waveform shown in fig. 16. As shown in fig. 16 (a), if the signal waveform outputted from the signal generating device 8 is a Sin waveform, the pressure supplied from the regulator 38 changes as shown in fig. 16 (b), and the negative pressure of the ejector 37 prevents vibration from being applied to the meniscus at the tip of the nozzle 6 of the inkjet head 10 as shown in fig. 16 (c).

The coating control method of the present embodiment is implemented according to the sequence shown in the left flowchart of fig. 8. First, the liquid material application device is turned on (started), and the liquid material application device performs an initialization operation (initial operation). Then, relevant device parameters (data setting) of the produced product (variety) are set. The device parameters are such as: workpiece size, coating area, injection conditions, etc. If these settings are completed, preparations for performing production are completed.

Next, the work is supplied from a work supply device, which is generally called a loader, to a surface plate of the liquid material application device. After the workpiece placed on the table is positioned on the table, the application position on the workpiece is confirmed, and the relative positional deviation between the liquid material application device and the application position on the workpiece is corrected (aligned). This correction is performed by using an imaging device such as a CCD camera for the position of the workpiece and performing image processing on the captured image. At this time, in addition to the physical correction for rotating and moving the platform, program correction for correcting the coordinate position of the robot movement-related program is also performed. By performing the processing thus far, preparation for correctly applying coating to a predetermined coating position on the workpiece positioned on the apparatus stage is completed. If the above correction processing is finished, the coating work is started.

[ example 3]

The film formation method of this embodiment is an inkjet coating method in which the droplets are dried to such an extent that the dropped droplets do not flow, and then the next droplets are ejected and formed into a film by dropping. The liquid material used was a polyimide solution, and the substrate used was a glass substrate.

The polyimide solution is used for forming a semiconductor insulating layer and a liquid crystal panel insulating film. The glass substrate is placed on a stage capable of temperature adjustment in order to dry the dripping material to such an extent that the dripping material does not flow.

[ comparative example ]

The following situation was observed when a coating region having an angle of 25mm was coated at a pitch of 70 μm at 30 pl/droplet by the conventional inkjet coating method.

(A) Lateral (horizontal): the peripheral diffusion is about 0.5 to 1.0mm relative to the specified coating area.

(B) Longitudinal direction (height direction): the central part of the coating area is 80-85 nm, and the edge part is about 1000nm in height.

[ example 3]

Similarly, the following situation occurred after applying the ink jet coating method of this example to a 25mm square coating area at a pitch of 70 μm with four shots of 8 pl/droplet.

(A) Lateral (horizontal): the peripheral diffusion is about 0.05 to 0.1mm with respect to the predetermined coating region.

(B) Longitudinal direction (height direction): the central part of the coating area is 80nm to 100nm, and the edge part is about 80nm to 100nm in height.

As described above, it was confirmed that the film formation method of the present example achieves advantageous effects as compared with the conventional film formation methods shown in comparative examples. More specifically, it was confirmed that the method of the present example can achieve the effects of reducing irregularities formed on the film, reducing the level difference over the entire surface of the film, and also reducing the amount of edge bleeding.

(availability in industry)

The present invention is not limited to the inkjet printer, and can be applied to various inkjet recording apparatuses such as a precision spray/injection apparatus (including a coating apparatus) and a precision coating apparatus. The present invention is also applicable to inkjet patterning, for example, coating apparatus, drawing apparatus, and printing apparatus for applications such as printing of organic EL display panels, large color panels, and industrial marking images.

The ink jet recording method is also applicable to any of mechanical conversion methods such as piezoelectric type and bubble generation methods such as resistance thermal jet type.

Further, the present invention can be used for a lens coloring step in the lens manufacturing industry, or for posters and building material decorations in the large-scale printing industry.

Claims (6)

1. An ink-jet film forming method for forming a film by a plurality of ejection steps; the method is characterized in that after the first ejection action of the ink jet head is used for ejecting the liquid drops on the workpiece, when the liquid drops are ejected on the contact position or the overlapping position of the liquid drops dripped by the ejection, the liquid drops are ejected after the liquid drops on the workpiece reach a non-flowing dry state.

2. The inkjet film forming method according to claim 1, wherein in the first ejection operation, the droplets of the ejected droplet group are arranged to be separated from each other.

3. The inkjet film forming method according to claim 1 or 2, wherein the drying time of the droplets on the workpiece is shortened by raising the temperature of the stage on which the workpiece is placed.

4. The inkjet film forming method according to claim 1 or 2, wherein film formation is performed by an inkjet head having a plurality of ejection ports.

5. The inkjet film forming method according to claim 1 or 2, wherein the number of times of the ejection step is increased and the ejection amount per time is decreased.

6. The inkjet film forming method according to claim 1 or 2, wherein the wiring pattern is formed from a film.