Pattern forming method and inkjet printing apparatus

Abstract

The present application provides a pattern forming method and an inkjet printing device, which are high in precision, free from streaks or mottling, uniform in insulating and conductive properties, and good in adhesion of a coating film. The pattern forming method is characterized in that, in a manner in which a plurality of times of movement in a direction perpendicular to and parallel with a nozzle row direction of an ink ejection device in which a plurality of nozzle holes are arranged in the nozzle row direction are performed to eject droplets of ink from nozzles against a substrate as a printing medium to form a pattern, an ink having a ratio η2 / η1 of a viscosity η1 at a temperature at the time of ejection and a viscosity η2 at a temperature at the time of landing of 100 or more is used as the ink, and control is performed in such a manner that, in correspondence with a gray scale or a density of each pixel of the image data constituting the pattern, a liquid amount of the ink used in formation of a coating film of a dot constituting the pattern formed on the substrate and an adjacent dot do not have a constant periodicity, and the coating film as a whole of the pattern is non-uniform.

Description

[0001] This application is a divisional application of the invention patent application with application number 202180053394.5 (PCT / JP2021 / 029174), application date August 5, 2021 (file date February 28, 2023), and invention title "Method for Forming Patterns". Technical Field

[0002] This invention relates to a pattern forming method. More specifically, it relates to a method for forming highly precise patterns using inkjet printing, free from streaks or unevenness. Background Technology

[0003] In recent years, research and development have progressed in the technology of forming patterns for electronic devices using inkjet printing (hereinafter referred to as "inkjet printing") with ink containing functional materials.

[0004] Patent document 1 discloses a method for manufacturing a multilayer wiring substrate with an interlayer insulating film based on a droplet ejection method (inkjet method). However, depending on the combination of the substrate and the ink, a problem arises where protrusions occur. When patterns are formed across different substrates, the ink flows to the side of the substrate with higher wettability due to the difference in the wettability of each substrate to the ink.

[0005] Therefore, Patent Document 2 discloses a method for applying droplets of insulating film forming material at different distances from the periphery based on the wetting characteristics of the substrate on the substrate. However, when the wetting characteristics of each substrate are significantly different, ink flow problems arise. Furthermore, ink flow problems also arise when a pattern is formed across a substrate with uneven surfaces.

[0006] Accordingly, in Patent Document 3, which discloses the invention of the inventor of this application, the above-mentioned problem is solved by specifying the viscosity of the ink during the injection and after the ink has landed in the pattern formation of the insulating layer using inkjet method. However, the insulating layer forming ink with phase change mechanism has high dot fixation after landing, so streak-like unevenness occurs in the scanning direction, and it is believed that there is still room for improvement.

[0007] Furthermore, Patent Document 4 describes a method in a one-pass inkjet printer where, by grouping multiple adjacent pixels into a group and adjusting the amount of droplet ejected from a single pixel within that group, the number of pixels ejected from that group can be reduced, thus suppressing gloss streaks in the transport direction. However, our research shows that when this method is applied in a multipass printer, streaks can be observed in a direction orthogonal to the transport direction.

[0008] When printing high-resolution patterns, multiple passes are mainly used. However, in multiple passes, the long time between passes can easily cause uneven streaks.

[0009] Furthermore, streaks are not only an aesthetic issue, but they also contribute to uneven insulation and conductivity during the formation of insulating and conductive films, thus becoming a significant problem.

[0010] Furthermore, when a pattern is formed on the protrusion of the substrate, insufficient coverage of the pattern in the stepped areas can lead to problems such as poor insulation and conductivity.

[0011] Existing technical documents

[0012] Patent documents

[0013] Patent Document 1: Japanese Patent Application Publication No. 2003-309369

[0014] Patent Document 2: Japanese Patent Application Publication No. 2010-231287

[0015] Patent Document 3: International Publication No. 2015 / 002316

[0016] Patent Document 4: Japanese Patent Application Publication No. 2012-162057 Summary of the Invention

[0017] The problem that the invention aims to solve

[0018] The present invention was made in view of the above-mentioned problems / situations, and its solution is to provide a pattern forming method using inkjet printing that provides high precision without streaks or unevenness, uniform insulation and conductivity when using ink containing functional materials such as insulators and conductors, and good coating adhesion.

[0019] Methods for solving problems

[0020] In order to solve the above-mentioned problems, the inventors discovered, during the process of studying the causes of the above problems, that the causes of streaks and unevenness are related to the periodicity or randomness of the position where ink droplets fall, and made this invention.

[0021] That is, the above-mentioned problems involved in this invention are solved by the following means.

[0022] 1. A method for forming a pattern based on pattern image data using inkjet printing, characterized in that,

[0023] In an ink ejection device, where multiple nozzles are arranged in a row in an ink-dispensing pattern, the nozzles move multiple times perpendicularly and parallel to the direction of the nozzle row to eject ink droplets from the nozzles onto a substrate serving as a printing medium, thereby forming a pattern.

[0024] As the ink used, an ink in which the ratio η2 / η1 of the viscosity at the dispensing temperature and the viscosity η2 at the landing temperature is 100 or more is used, and the ratio is controlled in the following manner:

[0025] Corresponding to the grayscale or density of each pixel of the image data constituting the pattern, the amount of ink used in forming the coating film constituting the dots formed on the substrate does not have a constant periodicity with adjacent dots, and the overall coating film of the pattern is non-uniform.

[0026] 2. A method for forming a pattern based on pattern image data using inkjet printing, characterized in that,

[0027] In an ink ejection device, where multiple nozzles are arranged in a row in an ink-dispensing pattern, the nozzles move multiple times perpendicularly and parallel to the direction of the nozzle row to eject ink droplets from the nozzles onto a substrate serving as a printing medium, thereby forming a pattern.

[0028] As the ink used, an ink in which the ratio η2 / η1 of the viscosity at the dispensing temperature and the viscosity η2 at the landing temperature is 100 or more is used, and the ratio is controlled in the following manner:

[0029] The ink droplets used in the formation of the coating film constituting the dots of the pattern formed on the substrate are dropped multiple times, and

[0030] The position of the point where the droplet lands does not follow the order of the rows and columns of the pixels that constitute the image data, and does not have a constant periodicity.

[0031] 3. A method for forming a pattern based on pattern image data using inkjet printing, characterized in that,

[0032] In an ink ejection device having multiple nozzle holes, or in a manner where a substrate serving as a printing medium is moved multiple times, ink droplets are ejected from the nozzles of the ink ejection device onto the substrate serving as the printing medium to form a pattern.

[0033] As the ink used, an ink in which the ratio η2 / η1 of the viscosity at the dispensing temperature and the viscosity η2 at the landing temperature is 100 or more is used, and the ratio is controlled in the following manner:

[0034] The ink droplets used in the formation of the coating film constituting the dots of the pattern formed on the substrate are dropped multiple times, and

[0035] The position of the point where the droplet lands does not have a constant periodicity in the main scanning direction and the sub-scanning direction of the ink ejection device, and is discontinuous in the main scanning direction.

[0036] 4. The pattern forming method according to item 3, characterized in that,

[0037] The image data of the pattern is divided into multiple segments in a manner that prevents pixels from overlapping during overprinting, and in a manner that ensures the position of the droplet landing point does not have a constant periodicity in the main scanning direction and the sub-scanning direction of the ink ejection device, and is discontinuous in the main scanning direction.

[0038] The segmented image data are printed in sequence, overlapping each other.

[0039] 5. The pattern forming method according to item 3 or 4, characterized in that,

[0040] The ink ejection device moves back and forth relative to each other in the main scanning direction.

[0041] It spews out droplets of ink on both its way out and its return.

[0042] 6. The pattern forming method according to any one of items 3 to 5, characterized in that,

[0043] The ink ejection device moves relative to the sub-scanning direction in a combination of positive and negative directions.

[0044] 7. The pattern forming method according to any one of items 3 to 6, characterized in that control is performed in the following manner:

[0045] The amount of ink used in forming the coating film that constitutes the dots forming the pattern on the substrate corresponds to the gray level or density of each pixel of the image data constituting the pattern, and does not have a constant periodicity with adjacent dots, so the overall coating film as a pattern is non-uniform.

[0046] 8. The pattern forming method according to any one of items 1 to 7, characterized in that control is performed in the following manner:

[0047] The amount of ink at each point on the inner edge of the patterned portion, which forms the boundary between the patterned portion and the non-patterned portion on the substrate, is approximately the same.

[0048] 9. The pattern forming method according to any one of items 1 to 8, characterized in that control is performed in the following manner:

[0049] For a substrate with a convex shape, the amount of ink at each point on the edge forming the convex shape is approximately the same.

[0050] 10. The pattern forming method according to any one of items 1 to 9, characterized in that control is performed in the following manner:

[0051] For a substrate with a convex shape, the amount of ink at each point on the outer edge of the boundary between the inner and outer sides of the bottom surface forming the convex shape is greater than the amount of ink at each point on the edge forming the convex shape.

[0052] 11. The pattern forming method according to any one of items 1 to 10, characterized in that control is performed in the following manner:

[0053] For a substrate with a convex shape, the amount of liquid at the point on the outer edge of the boundary between the inner and outer sides of the bottom surface forming the convex shape changes continuously from the surface in contact with the convex shape to the surface in the outward direction.

[0054] 12. The pattern forming method according to any one of items 1 to 11, characterized in that control is performed in the following manner:

[0055] The average thickness of the coating film constituting the pattern is 15 μm or more.

[0056] 13. The pattern forming method according to any one of items 1 to 12, characterized in that,

[0057] The amount of ink that falls to form the coating at each point constituting the pattern is varied in multiple ways.

[0058] 14. The pattern forming method according to any one of items 1 to 13, characterized in that,

[0059] The ink used may be any type of ink among hot-melt type, gel-type, or thixotropic type.

[0060] 15. The pattern forming method according to any one of items 1 to 14, characterized in that,

[0061] Solder resist ink is used as the ink.

[0062] 16. An inkjet printing apparatus for forming a pattern based on image data of a pattern, characterized in that,

[0063] The pattern is formed by any one of the pattern forming methods described in items 1 to 15.

[0064] The effects of the invention

[0065] Through the above-described means of the present invention, a pattern forming method using inkjet printing can be provided that is highly precise and free of streaks or unevenness, has uniform insulation and conductivity properties when using inks containing functional materials such as insulators and conductors, and has good coating adhesion.

[0066] Although the mechanism of action or manifestation of the effects of the present invention is not clear, it is speculated as described below.

[0067] By using ink with a viscosity ratio η2 / η1 of 100 or higher between the viscosity η1 at the dispensing temperature and the viscosity η2 at the landing temperature, it is easy to obtain ink dispensing stability, thus enabling high-precision ink supply to the substrate. Furthermore, it is speculated that the ink supplied to the substrate can be quickly and easily fixed (pinning) to the contact lines on the substrate, preventing ink flow, and suppressing the formation of protrusions to create lines of uniform width, or to form high-precision patterns across different components.

[0068] Furthermore, by controlling the amount of ink used in forming the coating film that constitutes the pattern formed on the substrate so that the amount of ink used in forming the pattern does not have a constant periodicity with the adjacent dots and the overall coating film of the pattern is not uniform, it is possible to suppress the occurrence of streaks and unevenness in the scanning direction and eliminate the unevenness of insulation and conductivity caused by streaks and unevenness.

[0069] Furthermore, by using a multiple-pass method in which the nozzles of an ink ejection device arranged in a row are moved perpendicularly and parallel to the direction of the nozzle row multiple times to eject ink droplets from the nozzles onto the substrate, which serves as the printing medium, to form a pattern, it is easy to print high-resolution and high-fine patterns.

[0070] The pattern forming method using inkjet printing according to the present invention will be described in comparison with conventional pattern forming methods.

[0071] For example, a method is described in which the inkjet head is moved in the nozzle column direction to make the output resolution 1200 dpi using an inkjet head with a resolution of 600 dpi, and the image data is printed by moving the inkjet head multiple times.

[0072] Figure 1 The inkjet printing method shown is called the block method. In the first scan in the transport direction, printing is performed using the same nozzle, and the head moves a distance of 1200 dpi (21.2 μm) in the nozzle column direction. The 1200 dpi printing is completed in the second scan.

[0073] In this case, such as Figure 1As shown in the figure, the droplet landing is carried out continuously as "scan 1" and "scan 2", and streaks are easily generated in the transport direction.

[0074] Figure 2 The inkjet printing method shown is called the interleave method. In the first scan in the transport direction, printing is performed by skipping one pixel using the same nozzle. In the second scan in the transport direction, the pixels between the parts printed in the first scan are printed. Then, the head is moved 1200 dpi (21.2 μm) in the nozzle column direction. The same process is repeated for the third and fourth scans. The printing is completed with an output resolution of 1200 dpi.

[0075] In this case, as shown in the figure, the landing sequence also becomes periodic, like "scan 1" to "scan 4", which easily leads to streaks.

[0076] Figure 3 The inkjet printing method shown is a randomized, multiple-pass method for the so-called "random" landing involved in this invention. Printing at 1200 dpi is completed in a total of 8 passes to randomize the landing order. Furthermore, the number of passes can be increased. Additionally, the number of passes can be further increased by dividing the transport direction.

[0077] Because of this random, multiple-pass method, the droplets fall randomly, so the streaks do not become significant.

[0078] Furthermore, the term "random" as used in this invention refers to a non-human-made or unpredictable state in a pattern formation method under conditions predicated on control within the range described later, where the amount of liquid at points or the relative positional relationships of points are recognized as lacking overall uniformity or periodicity, or other regularity. Specifically, it refers to, for example... Figure 3 The state shown.

[0079] As can be inferred from the above comparative examples, the reason for the effectiveness of the present invention is that, in the pattern forming method of the present invention, due to the randomness of the landing location and order of ink droplets, it is believed that there is no periodicity between adjacent pixels or points in the printed image, and streaks and unevenness are difficult to occur overall. Attached Figure Description

[0080] Figure 1 This is a schematic diagram illustrating a pattern formation method using a block-based approach.

[0081] Figure 2 This is a schematic diagram illustrating a pattern-forming method using an interlacing technique.

[0082] Figure 3This is a schematic diagram illustrating the pattern forming method using a random multiple-pass method according to the present invention.

[0083] Figure 4 It is a graph that shows image data with uniform grayscale or density of each pixel.

[0084] Figure 5 It is a graph that shows image data where the grayscale or density of each pixel has a constant periodicity.

[0085] Figure 6 This is a diagram showing a grayscale image of 256 gray levels that does not have a constant periodicity with adjacent pixels.

[0086] Figure 7 It is based on Figure 6 The image data is printed to form a graphic representation of the liquid distribution at the dots.

[0087] Figure 8A This is a schematic diagram (front view) showing an inkjet printing apparatus that utilizes a multi-pass method.

[0088] Figure 8B This is a schematic diagram (top view) of an inkjet printing apparatus that utilizes a multi-pass printing method.

[0089] Figure 9 This diagram illustrates a method for printing at 1200 dpi using a single inkjet head with a resolution of 600 dpi through block printing.

[0090] Figure 10 It is a graph showing the image data used in a random multiple pass-through manner where the liquid volume is uniform at the point of formation.

[0091] Figure 11 This diagram illustrates a method of printing at 1200 dpi using a single inkjet head with a resolution of 600 dpi through random drop.

[0092] Figure 12 This is a diagram showing image data of the filling portion of Embodiment 1.

[0093] Figure 13 This is a photograph taken under an optical microscope at 100x magnification of printed material 1.

[0094] Figure 14 This is a diagram illustrating the printing method of Example 2.

[0095] Figure 15 This is a diagram showing image data of the filling section in Embodiment 2.

[0096] Figure 16 This is a diagram showing image data of the filling section in Example 3.

[0097] Figure 17 This is a photograph taken under an optical microscope at 100x magnification of printed material 3.

[0098] Figure 18 This is a diagram showing image data of the hollow circular portion of Embodiment 3.

[0099] Figure 19 It is printed material 3 A photograph of a hollow circle under an optical microscope at 100x magnification.

[0100] Figure 20 This is a diagram showing image data of the hollow circular portion of Embodiment 4.

[0101] Figure 21 It is printed material 4. A photograph of a hollow circle under an optical microscope at 100x magnification.

[0102] Figure 22 This is an enlarged schematic diagram of a printed substrate with Cu wiring patterns added.

[0103] Figure 23 This is a diagram showing image data printed onto the printing substrate of Example 5.

[0104] Figure 24 This is an explanatory diagram of the wiring section image data in Example 6.

[0105] Figure 25 This is an explanatory diagram of the wiring section image data in Example 7.

[0106] Figure 26 This is a diagram showing image data of the filling portion in Example 8.

[0107] Figure 27 This is a photograph taken under an optical microscope at 100x magnification of printed material 8.

[0108] Figure 28 This is a photograph of the printed material 9 (Comparative Example 1) under an optical microscope at 100x magnification.

[0109] Figure 29 The diagram illustrates a method for printing at a resolution of 2400 dpi using an inkjet head with a single nozzle and a resolution of 600 dpi, through random drop-off and segmented printing (image segmentation number 2).

[0110] Figure 30A The figure (1 scan to 8 scans) shows a method of printing at a resolution of 2400 dpi using an inkjet head with a single nozzle resolution of 600 dpi through random drop and segmented printing (image segmentation number 4).

[0111] Figure 30BThe figure (9 scans to 16 scans) shows a method of printing at a resolution of 2400 dpi using an inkjet head with a single nozzle resolution of 600 dpi through random drop and segmented printing (image segmentation number 4).

[0112] Figure 31 This diagram illustrates a method of printing at a resolution of 2400 dpi using a single inkjet head with a nozzle resolution of 600 dpi through random drop-off.

[0113] Figure 32 This diagram illustrates a method for printing at a resolution of 2400 dpi using a single inkjet head with a 600 dpi nozzle, through random droplet placement and segmented printing (image segmentation number 2), where the positions of the droplets ejected from the left-hand nozzle and the center nozzle are set to be the same in both the first and fifth scans.

[0114] Figure 33 This is a top view showing an inkjet printing apparatus 100 using a multi-pass method.

[0115] Figure 34 This is a diagram illustrating a method of printing using an inkjet printing apparatus 1 (the head moves in the X direction and the substrate moves in the Y direction).

[0116] Figure 35 This is a diagram illustrating a method of printing using an inkjet printing apparatus 100 (the head moves in the Y direction and the substrate moves in the X direction).

[0117] Figure 36 This diagram illustrates a printing method using an inkjet printing apparatus that moves a substrate in both the X and Y directions.

[0118] Figure 37 This diagram illustrates a method of printing using an inkjet printing apparatus in which the head moves in both the X and Y directions.

[0119] Figure 38 This diagram illustrates a bidirectional printing method in which an ink ejector moves relatively back and forth in the main scanning direction and ejects ink droplets in both the outgoing and returning paths.

[0120] Figure 39 This diagram illustrates a method of mixed printing in which the ink ejection device moves relative to the sub-scanning direction in a combination of forward and reverse directions.

[0121] Figure 40 This diagram illustrates a method for printing at a resolution of 2400 dpi using a 600 dpi inkjet head with four nozzles through segmented printing.

[0122] Figure 41This diagram illustrates a printing method where the direction of the nozzle array is not perpendicular or parallel to the X and Y directions, but rather inclined.

[0123] Figure 42 This diagram illustrates a printing method in which the direction of the ink ejection device itself is not perpendicular or parallel to the X and Y directions, but rather tilted.

[0124] Figure 43 This diagram illustrates a method of printing at a resolution of 2400 dpi using multi-grayscale image data and a single inkjet head with a nozzle resolution of 600 dpi through random drop-off.

[0125] Figure 44 This diagram illustrates a method of printing at 2400 dpi using a single inkjet head with a resolution of 600 dpi, employing an interleaved and segmented printing process. Detailed Implementation

[0126] The pattern forming method of the present invention is a pattern forming method based on image data of a pattern using inkjet printing. It is characterized in that, in a method where an ink ejection device, with multiple nozzles arranged in a column direction perpendicular and parallel to the direction of the nozzle column, ejects ink droplets from the nozzles onto a substrate serving as a printing medium to form a pattern, the ink used has a viscosity η1 at the ejection temperature and a viscosity η2 at the landing temperature with a ratio η2 / η1 of 100 or more, and is controlled at least (1) in such a way that the image constituting the pattern... The grayscale or density of each pixel in the data corresponds such that the amount of ink used in forming the coating film constituting the pattern formed on the substrate does not have a constant periodicity with adjacent points, and the overall coating film constituting the pattern is non-uniform, or (2) it is controlled in such a way that the droplets of ink used in forming the coating film constituting the pattern formed on the substrate fall multiple times, and the position of the droplet falling point does not follow the order of the rows and columns of the pixels constituting the image data, and does not have a constant periodicity.

[0127] This feature is a characteristic of the common or corresponding technologies in the following embodiments.

[0128] Furthermore, the pattern forming method of the present invention is (3) a pattern forming method based on pattern image data using inkjet printing, characterized in that, in a method in which an ink ejection device having multiple nozzle holes or a substrate serving as a printing medium is moved multiple times to eject ink droplets from the nozzle of the ink ejection device to the substrate serving as the printing medium to form a pattern, the ink used is an ink in which the ratio η2 / η1 of the viscosity η1 at the ejection temperature and the viscosity η2 at the landing temperature is 100 or more, and is controlled in such a way that the landing of the ink droplets used in forming a coating film constituting the points of the pattern formed on the substrate is repeated multiple times, and the position of the landing point of the droplets does not have a constant periodicity in the main scanning direction and the sub-scanning direction of the ink ejection device, and is discontinuous in the main scanning direction.

[0129] As an embodiment of the present invention, regarding the pattern forming method of (3) above, from the viewpoint of preventing streaks, unevenness, etc., it is preferable to divide the image data of the pattern into multiple segments in such a way that each pixel does not overlap in the case of overlapping printing, and in such a way that the position of the droplet landing point does not have a constant periodicity in the main scanning direction and the sub-scanning direction of the ink ejection device, and is discontinuous in the main scanning direction, and then sequentially overlap printing the segmented image data.

[0130] As an embodiment of the present invention, regarding the pattern forming method of (3) above, from the viewpoint of preventing streaks, unevenness, etc., it is preferable that the ink ejection device moves back and forth relatively in the main scanning direction and ejects ink droplets in both the outgoing and returning paths.

[0131] As an embodiment of the present invention, regarding the pattern forming method of (3) above, from the viewpoint of preventing streaks, unevenness, etc., it is preferable that the ink ejection device moves relative to the sub-scanning direction in a combination of positive and negative directions.

[0132] As an embodiment of the present invention, regarding the pattern forming method of (3) above, from the viewpoint of preventing streaks, uneven patches, etc., it is preferable to control it in the following manner: the amount of ink used in forming the coating film constituting the dots formed on the substrate corresponds to the gray level or concentration of each pixel of the image data constituting the pattern, and does not have a constant periodicity with adjacent dots, so that the coating film as a whole is uneven.

[0133] As an embodiment of the present invention, from the viewpoint of preventing streaks, uneven patches, etc., it is preferable to control the ink volume at each point on the inner edge of the patterned portion at the boundary between the patterned portion and the non-patterned portion formed on the substrate, so that the amount of ink is approximately the same.

[0134] As an embodiment of the present invention, from the viewpoint of preventing poor insulation and conductivity, it is preferable to control it in the following manner: for a substrate with a convex shape, the amount of ink at each point on the edge forming the convex shape is approximately the same.

[0135] As an embodiment of the present invention, from the viewpoint of preventing poor insulation and conductivity, it is preferable to control it in the following manner: for a substrate with a convex shape, the amount of ink at each point on the outer edge of the boundary between the inner and outer sides of the bottom surface forming the convex shape is greater than the amount of ink at each point on the edge forming the convex shape.

[0136] As an embodiment of the present invention, from the viewpoint of preventing poor insulation and conductivity, it is preferable to control the liquid level in the following manner: for a substrate with a convex shape, the liquid level at the point on the outer edge of the boundary between the inner and outer sides of the bottom surface forming the convex shape is continuously varied from the surface in contact with the convex shape to the surface in the outward direction.

[0137] As an embodiment of the present invention, from the viewpoint of preventing poor insulation and conductivity, it is preferable to control the process in such a way that the average thickness of the coating film constituting the pattern is 15 μm or more.

[0138] As an embodiment of the present invention, from the viewpoint of preventing streaks, uneven patches, etc., it is preferable to vary the amount of ink that falls in order to form the coating at each point constituting the pattern.

[0139] As an embodiment of the present invention, from the viewpoint of the formation of high-precision patterns, it is preferable to use any type of ink among hot-melt type, gel-type, or thixotropic type as the ink.

[0140] As an embodiment of the present invention, from the viewpoint of application consistent with the purpose of the invention, and from the viewpoint of solving the problem of protecting circuit patterns with insulating film as the present invention, solder resist ink is preferably used as the ink.

[0141] The pattern forming method of the present invention is applicable to inkjet printing apparatus.

[0142] The present invention, its constituent elements, and specific embodiments / solutions are described in detail below. Furthermore, in this application, "~" is used to encompass both lower and upper limits of the numerical values ​​described before and after it.

[0143] 1. Summary of the pattern forming method of the present invention

[0144] The pattern forming method of the present invention is a pattern forming method based on pattern image data using inkjet printing. Its characteristic is that, in a method where an ink ejection device, with multiple nozzles arranged in a column direction perpendicular and parallel to the direction of the nozzle column, ejects ink droplets from the nozzles onto a substrate serving as a printing medium to form a pattern, the ink used has a viscosity η1 at the ejection temperature and a viscosity η2 at the landing temperature with a ratio η2 / η1 of 100 or more, and at least...

[0145] (1) Controlled in such a way that, corresponding to the grayscale or density of each pixel of the image data constituting the pattern, the amount of ink used in forming the coating film constituting the points of the pattern formed on the substrate does not have a constant periodicity with adjacent points, and the overall coating film of the pattern is non-uniform, or

[0146] (2) Controlled in such a way that the ink droplets used in forming the coating film constituting the pattern formed on the substrate fall multiple times, and the positions of the droplets falling are not in the order of the rows and columns of the pixels constituting the image data, and do not have a constant periodicity.

[0147] In addition, (3) a pattern forming method using inkjet printing based on pattern image data is characterized in that, in a method in which an ink ejection device having multiple nozzle holes or a substrate serving as a printing medium moves multiple times to eject ink droplets from the nozzle of the ink ejection device to the substrate serving as the printing medium to form a pattern, the ink used is an ink in which the ratio η2 / η1 of the viscosity η1 at the ejection temperature and the viscosity η2 at the landing temperature is 100 or more, and is controlled in such a way that the ink droplets used in forming a coating film constituting the points of the pattern formed on the substrate fall multiple times, and the position of the point where the droplets fall does not have a constant periodicity in the main scanning direction and the sub-scanning direction of the ink ejection device, and is discontinuous in the main scanning direction.

[0148] Furthermore, the pattern forming method used in this invention is characterized by, as previously described, a so-called "multiple-pass method" in which droplets forming ink are ejected from the nozzle onto the substrate, which serves as the printing medium, by moving the nozzle column of an ink ejection device, which is perpendicular and parallel to the direction of the nozzle column, multiple times. Details of the device used in this invention will be described later.

[0149] Regarding (3), the feature is that an ink ejection device having multiple nozzle holes or a substrate as a printing medium is moved multiple times to eject ink droplets from the nozzle of the ink ejection device onto the substrate as the printing medium in order to form a pattern.

[0150] Furthermore, the ink used in this invention is characterized in that the ratio η2 / η1 of the viscosity at the dispensing temperature and the viscosity η2 at the landing temperature is 100 or more. A detailed description of the ink will follow later.

[0151] The embodiments and constituent elements of the present invention will be described below in sequence.

[0152] 1.1 Pattern Formation Method Using Random Droplet Multiple Passages

[0153] The pattern forming method of the present invention is characterized by controlling the ink volume used in forming the coating film of the dots forming the pattern on the substrate in a manner corresponding to the gray level or density of each pixel of the image data constituting the pattern, such that the ink volume of the coating film of the dots forming the pattern on the substrate does not have a constant periodicity with the adjacent dots, and the overall coating film of the pattern is non-uniform.

[0154] Furthermore, here, "non-uniformity" means that there are places where the liquid volume is substantially the same within a range of ±5%, but the points with the same liquid volume are not arranged periodically.

[0155] As an example of the constant periodicity between the amount of ink used in the formation of dots and adjacent dots, there is... Figure 4 as well as Figure 5 The example shown illustrates the use of image data with a constant periodicity in grayscale or density of each pixel for pattern formation.

[0156] In this specification, the method that satisfies the above control conditions is referred to as the "random dripping multiple passes method".

[0157] Furthermore, the term "random" in this invention refers to a non-human-induced or unpredictable state in a pattern formation method under controlled conditions (described later), where the amount of liquid at points or the relative positional relationships of points are recognized as lacking overall uniformity or periodicity, or other regularity. Specifically, it refers to, for example... Figure 7 The state shown.

[0158] Furthermore, in this invention, a "dot" refers to a pixel, the smallest unit constituting an ink image formed onto a printing medium by inkjet printing, and refers to a coating portion formed by a single droplet of ink. Therefore, a pixel in an ink image corresponding to a single pixel in the image data of the printed object may also be formed by multiple dots (droplets).

[0159] The following describes one example of an embodiment of the pattern forming method using a random droplet multiple pass method according to the present invention. It is not limited to the embodiments / schemes described below, and is included in the scope of the present invention as long as the above control conditions are met.

[0160] This embodiment describes the image data and the ink volume distribution.

[0161] In the random droplet multiple-pass method involved in this invention, the liquid volume at each point is changed in accordance with the grayscale or density of each pixel. Therefore, the image data of the random droplet multiple-pass method is preferably, for example, as shown in the example... Figure 6 The image shown is a 256-grayscale grayscale image where adjacent pixels do not have a constant periodicity.

[0162] As a method for creating multi-grayscale random image data, it involves image processing of grayscale images. For example, by using Adobe Photoshop to perform noise filtering on a 30% grayscale image with 256 gray levels, it is possible to create images like... Figure 16 Random multi-grayscale image data.

[0163] Based on this multi-grayscale image data, for example, the liquid volume can be dispensed in such a way that the black portion of grayscale 0 to 86 is 7 pL, the gray portion of grayscale 87 to 172 is 3.5 pL, and the white portion of grayscale 173 to 255 is 0 pL.

[0164] Figure 7 It is based on Figure 6 The image data is printed to form a dotted liquid distribution pattern. By randomly configuring the liquid volume, streaks and uneven patches can be suppressed.

[0165] Next, the inkjet printing apparatus and printing method in this embodiment will be described.

[0166] Figure 8 is a schematic diagram showing the inkjet printing apparatus 1 in this embodiment. In the apparatus shown in Figure 8, a cartridge 2 with an inkjet head 3 having a resolution of 600 dpi and capable of ejecting ink is mounted on a linear stage 4 in the X direction. The head 3 moves in the X direction. The details of the apparatus will be described later. In addition, a table 5 for placing a substrate is mounted on a linear stage 6 in the Y direction and moves in the Y direction (conveying direction).

[0167] The pattern formation using a random, multiple-drop method in this embodiment can be achieved through block printing. Figure 9 This demonstrates a method for printing at 1200 dpi using a single inkjet head with a resolution of 600 dpi via block printing.

[0168] As shown in Figure 8, the inkjet head 3 moves in the Y direction (conveyor direction) and performs the first scan of printing using the ink volume allocated according to the image data. Then, the head moves 21.2 μm in the X direction (equivalent to one pixel at 1200 dpi) and performs the second scan of printing using the ink volume allocated according to the image data, completing the 1200 dpi printing.

[0169] 1.2 Pattern Formation Method Using Random Multiple-Pass Mode (A)

[0170] As an embodiment of the present invention, it is preferable to control the process in such a way that the ink droplets used in forming the coating film constituting the pattern formed on the substrate fall multiple times, and the positions of the droplet landing points do not follow the order of the rows and columns of the pixels constituting the image data, and do not have a constant periodicity.

[0171] In this specification, the method that satisfies the above control conditions is referred to as "random multiple pass mode (A)".

[0172] The following describes one example of an embodiment of the pattern forming method using the random multiple-pass mode (A) according to the present invention, but is not limited to the embodiments / schemes described below. As long as the above control conditions are met, they are included in the scope of the technology of the present invention.

[0173] Figure 10 This refers to image data used in a random multiple-pass mode, where each point is formed by a uniform liquid volume. Alternatively, data used in a random multiple-pass mode, such as... Figure 6 Random image data with multiple gray levels is used to form points using different liquid volumes.

[0174] This describes the placement of ink in this embodiment.

[0175] In a single scan, points are formed by placing them discontinuously and at intervals along the rows and columns, creating a non-constant interval. In subsequent scans, points are similarly formed at locations where no points were previously formed, ensuring no repetition. The number of points formed in each scan may also be non-constant.

[0176] Furthermore, the number of scans can be increased further.

[0177] Next, the printing method in this embodiment will be described.

[0178] Figure 11 This demonstrates a method for printing at 1200 dpi using a single inkjet head with a resolution of 600 dpi through random drop.

[0179] exist Figure 3 In the pattern formation using a random multiple-pass method shown in this embodiment, such as Figure 11As shown, after the inkjet head performs printing based on 4 scans in the Y direction (conveyor direction), it moves 21.2 μm in the X direction (equivalent to 1 pixel of 1200 dpi) and performs printing based on 4 scans in the Y direction again, thus completing the printing with a total of 8 moves (throughs) (refer to Figure 8 for the device).

[0180] 1.3 Pattern Formation Method Using Random Multiple-Passage Method (B)

[0181] As an embodiment of the present invention, a pattern forming method using inkjet printing based on pattern image data is characterized in that, in a method in which an ink ejection device having multiple nozzle holes or a substrate serving as a printing medium is moved multiple times to eject ink droplets from the nozzles of the ink ejection device onto the substrate serving as the printing medium to form a pattern, the ink used is an ink in which the ratio η2 / η1 of the viscosity η1 at the ejection temperature and the viscosity η2 at the landing temperature is 100 or more, and is controlled in such a way that the ink droplets used in forming a coating film constituting the points of the pattern formed on the substrate fall multiple times, and the positions of the points where the droplets fall do not have a constant periodicity in the main scanning direction and the sub-scanning direction of the ink ejection device, and are discontinuous in the main scanning direction.

[0182] In this specification, the method that satisfies the above control conditions is referred to as "random multiple pass method (B)".

[0183] The following describes one example of an embodiment of the pattern forming method using the random multiple-pass method (B) according to the present invention, but is not limited to the embodiments / schemes described below. As long as the above control conditions are met, they are included in the scope of the technology of the present invention.

[0184] In the pattern forming method using the random multiple-pass mode (A) described in 1.2, a pattern is formed by repeatedly moving the nozzles of an ink dispensing device, which has multiple nozzle holes arranged in a column direction, perpendicular and parallel to the direction of the nozzle column, and dispensing ink droplets from the nozzles onto the substrate, which is a printing medium. However, in this embodiment, a pattern is formed by repeatedly moving the ink dispensing device or the substrate, which is a printing medium, with the nozzles of the ink dispensing device dispensing ink droplets from the nozzles onto the substrate, which is a printing medium.

[0185] Through further research, the inventors discovered that the main scanning direction and the secondary scanning direction of the ink ejection device can also be neither perpendicular to nor parallel to the nozzle array. Whether the ink ejection device and the substrate as the printing medium move to form a pattern or both move to form a pattern, streaks and unevenness are less likely to occur, as will be described later.

[0186] Furthermore, in the pattern formation method using the random multiple-pass method (A) described in 1.2, the control is characterized by the following: the position of the droplet landing point does not follow the order of the rows and columns of pixels constituting image data, and does not have a constant periodicity. However, in this embodiment, the control is characterized by the following: the control does not have a constant periodicity in the main scanning direction and the sub-scanning direction of the ink ejection device, and is discontinuous in the main scanning direction. That is, it is known that if the control is performed in a way that the main scanning direction and the sub-scanning direction of the ink ejection device do not have a constant periodicity, and further in a way that is discontinuous in the main scanning direction, then even if there is a partial continuity in the sub-scanning direction, streaks and unevenness are less likely to occur.

[0187] 1.3.1 Segmented Printing

[0188] As an embodiment of the present invention, it is also preferred to divide the image data of the pattern into multiple segments in such a way that the pixels do not overlap in the case of overlapping printing, and in such a way that the position of the point where the droplet falls does not have a constant periodicity in the main scanning direction and the sub-scanning direction of the ink ejection device, and is discontinuous in the main scanning direction, and then sequentially overlap the segmented image data.

[0189] In this specification, the printing method that meets the above control conditions is referred to as "segmentation printing".

[0190] The following describes one example of an embodiment of the pattern forming method using segmented printing according to the present invention, but is not limited to the embodiments / schemes described below. As long as the above control conditions are met, they are included in the scope of the technology of the present invention.

[0191] Figure 29 This demonstrates a method for printing at a resolution of 2400 dpi using a single inkjet head with a nozzle resolution of 600 dpi, through random drop-out and segmented printing. Figure 29 In this process, source image data formed by uniform liquid volume at each point is used, but alternatively, data such as... Figure 6 Multiple grayscale random source image data are used to form points using different liquid volumes.

[0192] In segmented printing, the source image data is divided into two parts to create segmented image data, and then each segmented image data is printed sequentially by overlapping. Therefore, the segmented image data is created in a way that prevents pixels from overlapping during overlapping printing. Furthermore, the segmented image data is created such that the positions of the droplet landing points do not have a constant periodicity in the main scanning direction and the sub-scanning direction of the ink ejection device, and are discontinuous in the main scanning direction.

[0193] Image segmentation can be achieved using image processing software such as Adobe Photoshop 2020. For example, Photoshop can be used to convert a grayscale image to monochrome 2-grayscale using methods such as error diffusion, creating random black and white images. Next, the image's tones are inverted to create inverted black and white images. The resulting two images become segmented images with randomly falling, non-overlapping black-filled data.

[0194] The following is a comparison Figure 29 30 and 31 are used to illustrate segmented printing.

[0195] Figure 31 This paper demonstrates a method for printing at a resolution of 2400 dpi using a single inkjet head with a nozzle resolution of 600 dpi and random dropouts. In this method, printing is performed for each column in the main scanning direction.

[0196] exist Figure 31 In printing, for example, the main scanning direction of a column is printed using two consecutive scans, namely scan 1 and scan 2. On the other hand, in segmented printing, such as... Figure 29 As shown, the printing of columns in the main scanning direction is completed through two non-continuous scans, scan 1 and scan 5.

[0197] In this way, in segmented printing, the time until the printing of the columns in the main scanning direction is completed is relatively long, so the ink is easy to fix, the ink flow can be suppressed, and streaks and unevenness are less likely to occur.

[0198] Figure 30A as well as Figure 30B This demonstrates dividing the source image data into four parts for comparison. Figure 29 The same segmented printing method is used. In this case, the columns in the main scanning direction are printed through four non-continuous scans: scan 1, scan 5, scan 9, and scan 13.

[0199] In this way, by increasing the number of segments of the source image data, the number of scans until the printing of the columns in the main scanning direction is completed increases, so the time until the printing is completed is further extended, making it more difficult for streaks and unevenness to occur, and reducing surface roughness.

[0200] Furthermore, printing is performed in the row direction before the columns in the main scanning direction are completed. Therefore, even when using inks with high viscosity at landing and fast phase transfer time, the ink is less likely to be fixed in a linear pattern in the main scanning direction, and streaks and unevenness are less likely to occur. In addition, by increasing the number of scans, landing offset caused by interaction with the ink density (dot) of the previous landing in adjacent landings can be reduced, thus improving pattern formation.

[0201] In this embodiment, random landing refers to control in such a way that the position of the droplet landing point does not have a constant periodicity in the main scanning direction and the sub-scanning direction of the ink ejection device, and is discontinuous in the main scanning direction.

[0202] Figure 32 Showing the process and Figure 29 The same segmented printing method is used, but in both the 1st and 5th scans, the droplets ejected from the nozzle at the left end and the nozzle in the center land at the same positions.

[0203] The streaks and unevenness that this invention addresses are prone to occur when the position of the droplet landing point is periodic or regular in the column direction of the main scanning direction, but are less likely to occur even if they are periodic or regular in the row direction. Therefore, as Figure 32 As shown, in a portion of the scan, even if the landing points of droplets ejected from different nozzles are set to be the same, streaks and unevenness can be effectively suppressed.

[0204] 1.3.2 Two-way printing

[0205] As an embodiment of the present invention, it is also preferred that the ink ejection device moves back and forth relatively in the main scanning direction, ejecting ink droplets in both the outgoing and returning paths.

[0206] In this specification, the printing method that meets the above control conditions is referred to as "two-way printing".

[0207] The following describes one example of an embodiment of the pattern forming method using bidirectional printing according to the present invention, but is not limited to the embodiments / schemes described below. As long as the above control conditions are met, they are included in the scope of the present invention.

[0208] Figure 38 This illustrates a method for bidirectional printing in which the ink ejection device moves relatively back and forth in the main scanning direction, ejecting ink droplets in both the outgoing and returning paths. Furthermore, in Figure 38 In the process, printing can be done in segments, but it is not always necessary to do so.

[0209] In the first scan, the ink ejection device moves relative to each other in the direction of the arrow while ejecting ink droplets (outbound movement). Next, in the second scan, the ink ejection device moves relative to each other in the direction of the arrow while ejecting ink droplets, with the column of dots formed to the right of the column of dots formed in the first scan (return movement). This process is repeated, completing the printing process with a total of eight scans.

[0210] Furthermore, "relatively moving" means that in this embodiment, the ink ejection device and the substrate as the printing medium can move either one or both. In the positional relationship between the ink ejection device and the substrate as the printing medium, the ink ejection device moves relatively.

[0211] Therefore, in Figure 38 In the first scan, the substrate can be fixed so that the ink ejection device moves in the direction of the arrow, or the ink ejection device can be fixed so that the substrate moves in the opposite direction of the arrow.

[0212] In such Figure 29 In the unidirectional printing shown, the ink ejection device moves back and forth relative to each other in the main scanning direction, but only ejects ink droplets in the outgoing path and only moves in the returning path. Therefore, by performing bidirectional printing, printing time can be shortened and productivity increased.

[0213] 1.3.3 Mixed forward and reverse printing

[0214] As an embodiment of the present invention, it is also preferred that the ink ejection device moves relative to the sub-scanning direction in a combination of positive and negative directions.

[0215] In this specification, the printing method that meets the above control conditions is referred to as "forward and reverse hybrid printing".

[0216] The following describes one example of an embodiment of the pattern forming method using forward and reverse hybrid printing according to the present invention, but is not limited to the embodiments / schemes described below. As long as the above control conditions are met, they are included in the scope of the technology of the present invention.

[0217] Figure 39 This illustrates a method for mixed forward and reverse printing in which the ink ejection device moves relative to the sub-scanning direction in a combination of forward and reverse directions. Furthermore, in Figure 39 In the process, printing can be done in segments, but it is not always necessary to do so.

[0218] In the first scan, the ink ejection device moves relative to the main scanning direction, ejecting ink droplets. Next, in the second scan, the ink ejection device moves relative to the direction of the arrow, forming a column of dots spaced one dot apart to the right of the column of dots formed in the first scan, and then moves in the main scanning direction, ejecting ink droplets. Then, in the third scan, the ink ejection device moves relative to the direction of the arrow, forming a column of dots between the columns of dots formed in the first scan and the columns of dots formed in the second scan, and then moves in the main scanning direction, ejecting ink droplets. This process is repeated, completing the printing process with a total of eight scans.

[0219] In such Figure 29In forward printing, where the ink ejection device moves only in one direction, dots are formed adjacent to the formed dots, leading to streaks and unevenness because adjacent dots are formed before the ink in the dots solidifies. Conversely, in mixed forward and reverse printing, dots are formed at intervals from the formed dots, resulting in adjacent dots forming after the ink in the dots solidifies, reducing the likelihood of streaks and unevenness. Furthermore, in mixed forward and reverse printing, the intervals between the formed dots reduce landing offsets caused by interaction with the previously landed ink (dots) during adjacent landings, improving pattern formation.

[0220] 1.3.4 Application of the random dripping multiple-pass method

[0221] As an embodiment of the present invention, it is further preferred to control the ink in such a way that the amount of ink used in forming the coating film constituting the dots of the pattern formed on the substrate corresponds to the gray level or concentration of each pixel constituting the image data, and does not have a constant periodicity with adjacent dots, so that the overall coating film constituting the pattern is non-uniform.

[0222] Figure 43 This demonstrates a method for printing at a resolution of 2400 dpi using multi-grayscale image data and a single inkjet head with a nozzle resolution of 600 dpi through random drop-off.

[0223] As the image data used in the random multiple-pass method involved in this invention, other data such as... can also be used. Figure 31 The image data is used to form points using a uniform liquid volume, but it can also be used as... Figure 43 The image data consists of multiple grayscale values, and each pixel is represented by a different amount of liquid to form points. By combining random droplet passing through multiple times with random passing through multiple times, the randomness of adjacent points is further improved, making it more difficult for streaks and unevenness to occur.

[0224] Furthermore, as an embodiment of the present invention, depending on the shape of the formed pattern, it is preferable to control the ink volume of each droplet (dot) on the inner edge of the patterned portion at the boundary between the patterned portion and the non-patterned portion formed on the substrate to be approximately the same. Here, "approximately the same ink volume" means that the difference in ink volume is within ±5%.

[0225] In addition, when the printing medium is a substrate with a convex shape, such as a wiring board for an electronic device, it is preferable to control it in such a way that the amount of ink in each droplet of the point (droplet) forming the edge of the convex shape is approximately the same.

[0226] Furthermore, it is preferable to control the ink volume per droplet at the outer edge of the boundary between the inner and outer sides of the bottom surface of the convex portion, compared to the droplets at the edge of the convex portion.

[0227] In addition, in the embodiment, it is preferable to control the liquid volume of the droplets at the outer edge of the boundary between the inner and outer sides of the bottom surface of the convex portion continuously from the surface in contact with the convex portion to the surface in the outward direction.

[0228] As an embodiment of the present invention, although it also depends on the properties of the ink used and the purpose of the pattern formed, it is preferred from the viewpoint of the effect performance of the present invention to control the average thickness of the coating film of the dots (droplets) constituting the pattern to be 15 μm or more.

[0229] In addition, in an embodiment, based on the same viewpoint as above, it is also preferable to vary the amount of ink that falls in order to form the coating film constituting each point (droplet) of the pattern.

[0230] The various implementation methods / conditions described above are specifically described in the examples described later.

[0231] 1.4 ink

[0232] The ink used in the forming method of the present invention is characterized in that the ratio η2 / η1 of the viscosity η1 at the temperature when the ink is dispensed and the viscosity η2 at the temperature when the ink lands is 100 or more.

[0233] By making η2 / η1 100 or more, the occurrence of protrusions can be suppressed, and high-precision patterns can be formed. In addition, by making η2 / η1 200 or more, and further 500 or more, the formation of high-precision patterns on dissimilar parts and substrates with uneven surfaces is improved, so it is preferred.

[0234] Furthermore, there are no particular limitations regarding the viscosity at the time of ink ejection and at the time of ink landing, as long as it is within the range of the above ratio. The viscosity (η1) at the temperature of ejection, for example, 75°C, is preferably in the range of 3 mPa·s to 15 mPa·s from the point of inkjet head ejection performance.

[0235] On the other hand, the viscosity (η2) at room temperature (25°C) when the ink falls is preferably 1×10⁻⁶. 2 mPa·s~1×10 4 mPa·s.

[0236] The viscosity (η2) is 1×10 2 mPa·s~1×104 At mPa·s, the ink is immobilized on the substrate upon landing, which can suppress the occurrence of protrusions, etc.

[0237] In the pattern forming method according to the present invention, in particular, by using this ink, it is possible to prevent the occurrence of poor insulation, poor conductivity, etc. In particular, the effect is significant when forming patterns across different components or components with convex shapes.

[0238] In this invention, the ink is preferably any type of ink among the hot-melt type, gel-type type, or thixotropic type, as described later.

[0239] Viscosity

[0240] "Viscosity η2 at the landing temperature" refers to the viscosity of the ink reached before the flow of ink (not caused by the impact of the landing) substantially occurs due to the wetting and spreading of ink on the substrate. Specifically, it is the viscosity reached within 1 second from the time the ink lands on the substrate. In this invention, it is set as the temperature of the substrate at the time the ink lands.

[0241] On the other hand, regarding "viscosity η1 at the temperature at which ink is ejected", let it be the temperature of the head at the time when the ink is ejected from the head.

[0242] For viscosity measurement, the ink is placed in a temperature-controlled pressure-controlled rheometer (e.g., Physica MCR300, manufactured by Anton Paar) and heated to 100°C. The ink is then cooled to 25°C at a cooling rate of 0.1°C / s, and the viscosity is measured. A conical plate with a diameter of 75.033 mm and a cone angle of 1.017° (e.g., CP75-1, manufactured by Anton Paar) can be used for the measurement.

[0243] In addition, temperature control can be performed using a temperature control device, such as the Peltier element-type temperature control device (TEK150P / MC1) attached to the Physica MCR300.

[0244] <Methods for controlling viscosity ratio η2 / η1>

[0245] The viscosity ratio η2 / η1 of the ink involved in this invention can be appropriately satisfied, for example, by setting physical conditions such as the composition of the ink, the temperature when the ink falls, and humidity.

[0246] The ink preferably exhibits properties such as viscosity variation due to any phase change mechanism, including thermal melting, thixotropy, or gelation. The ink demonstrates a phase change function from the time of dispensing to the time of landing, thereby satisfying the viscosity ratio η2 / η1 condition involved in this invention.

[0247] "Thermal melting" refers to heating and melting. "Thermal melting-based phase change mechanism" refers to the mechanism by which a phase changes from a heated (melted) and low-viscosity state (when ejected) to a high-viscosity state (when landing) through cooling.

[0248] From the perspective of appropriately representing the phase change mechanism based on thermal melting, it is preferable to change the ink temperature during ejection and landing. For example, it is preferable to perform either or both of ink heating during ejection and ink cooling during landing.

[0249] In this invention, when the temperature of the ink changes during ejection and landing, a temperature adjustment unit, such as a heater (heating unit) for heating the ink filled in the inkjet head or a cooling unit for cooling the substrate, can be appropriately used.

[0250] "Thixotropy" refers to the property of exhibiting intermediate properties between a plastic solid like a gel and a non-Newtonian liquid like a sol, with viscosity changing over time.

[0251] "Thixotropic phase transition mechanism" refers to the phase transition mechanism that changes from a low viscosity state (during injection) caused by shear stress generated by stirring, vibration, etc., to a high viscosity state (after landing) caused by reduced shear stress or quiescence.

[0252] For example, it is possible to appropriately use a shear stress-providing unit that applies agitation and vibration (micro-vibration) to the ink filled in the inkjet head to represent a thixotropic phase transition mechanism.

[0253] "Gel-based phase transition mechanism" refers to a phase transition mechanism in which the solute, initially in a low-viscosity state due to its independent mobility (during ejection), transitions to a high-viscosity state (during landing) through the interaction of polymer meshes, microparticle aggregation structures, etc., formed based on chemical or physical aggregation. In this case, it is preferable to include a gelling agent such as an oil gelling agent (described in detail later) in the ink.

[0254] From the viewpoint of appropriately representing the phase transition mechanism based on gelation, it is preferable to change the ink temperature during ejection and landing. For example, it is preferable to heat the ink to above the sol-gel phase transition temperature (gelation temperature) during ejection to perform solification and cool the ink to below the sol-gel phase transition temperature (gelation temperature) during landing to perform gelation.

[0255] <Thermosetting Inkjet Ink>

[0256] The ink used in this invention is preferably a thermosetting inkjet ink containing a compound with thermosetting functional groups and a gelling agent, and is a temperature-based sol / gel phase transfer thermosetting inkjet ink. Furthermore, the thermosetting inkjet ink more preferably contains a compound with photopolymerizing functional groups and a photopolymerization initiator.

[0257] Thermosetting functional groups

[0258] According to the point of thermosetting properties, the thermosetting functional group is preferably selected from at least one of the group consisting of hydroxyl, carboxyl, isocyanate, epoxy, (meth)acrylic acid, maleimide, mercapto and alkoxy groups.

[0259] Gelation Agents

[0260] The gelling agent is preferably maintained in a state of uniform dispersion in the cured film that has been cured by light and heat, thereby preventing moisture from penetrating into the cured film.

[0261] The gelling agent, which is dispersed in the cured film without hindering the curing of the ink, is preferably at least one of the compounds represented by the following general formula (G1) or (G2). Furthermore, in inkjet printing, it is preferred to have points with good pinning properties, capable of simultaneously ensuring the depiction of fine lines and film thickness, and excellent fine line reproducibility.

[0262] General formula (G1): R1-CO-R2

[0263] General formula (G2): R3-COO-R4

[0264] [In the formula, R1 to R4 each independently represent a straight-chain moiety having 12 or more carbon atoms, and may also be a branched alkyl chain.]

[0265] Ketone waxes represented by the general formula (G1) or ester waxes represented by the general formula (G2) have 12 or more carbon atoms in their linear or branched hydrocarbon groups (alkyl chains), thus further enhancing the crystallinity and water resistance of the gelling agent and creating more ample space in the carbon chamber structure described below. Therefore, ink media such as solvents and photopolymerizable compounds are easily and fully encapsulated within these spaces, further increasing the pinning properties of the ink.

[0266] In addition, the number of carbon atoms in the straight-chain or branched-chain hydrocarbon group (alkyl chain) is preferably 26 or less. When the number of carbon atoms is 26 or less, the melting point of the gelling agent will not be excessively increased, so there is no need to overheat the ink when extruding it.

[0267] Based on the above viewpoint, R1 and R2, or R3 and R4, are particularly preferably linear hydrocarbon groups with 12 or more but less than 23 carbon atoms. Furthermore, based on the viewpoint of increasing the ink's gelation temperature and causing rapid gelation of the ink upon application, any one of R1 or R2, or any one of R3 or R4, is preferably a saturated hydrocarbon group with 12 or more but less than 23 carbon atoms.

[0268] According to the above viewpoint, R1 and R2, or R3 and R4, are more preferably saturated hydrocarbon groups with 11 or more but less than 23 carbon atoms.

[0269] The content of the gelling agent is preferably in the range of 0.5% to 5.0% by mass relative to the total mass of the ink. By keeping the content of the gelling agent within the above range, the gelling agent exhibits good solubility and pinning effect on the solvent components, and also good water resistance when formed into a cured film. Furthermore, based on the above viewpoint, the content of the gelling agent in the inkjet ink is more preferably in the range of 0.5% to 2.5% by mass.

[0270] Furthermore, according to the following viewpoint, the gelling agent preferably crystallizes in the ink at a temperature below the gelation temperature of the ink. The gelation temperature refers to the temperature at which the viscosity of the ink changes drastically when the gelling agent transfers from the sol phase to the gel phase upon cooling of ink that has been solutized or liquefied due to heating. Specifically, the gelation temperature of the ink is defined as the temperature at which the viscosity rises sharply when the solutized or liquefied ink is cooled while the viscosity is measured using a viscoelasticity measuring device (e.g., MCR300, manufactured by Physica).

[0271] Compounds with photopolymerizable functional groups

[0272] Compounds with photopolymerizable functional groups (also called photopolymerizable compounds) are compounds that can polymerize or bridge upon irradiation with active light, thereby curing the ink. Examples of photopolymerizable compounds include free radical polymers and cationic polymers. Photopolymerizable compounds can also be monomers, polymerizable oligomers, prepolymers, or mixtures thereof. Inkjet inks may contain only one or more photopolymerizable compounds.

[0273] The free radical polymerizable compound is preferably an unsaturated carboxylic acid ester compound, more preferably a (meth)acrylate ester. Examples of such compounds include compounds having the aforementioned (meth)acrylate group.

[0274] Cationic polymerizable compounds can be epoxides, vinyl ethers, and oxobutanes, among others. Inkjet inks may contain only one or more cationic polymerizable compounds.

[0275] Photopolymerization Initiators

[0276] When the photopolymerization compound is a free radical polymerizable compound, a photoradical initiator is preferred; when the aforementioned photopolymerization compound is a cationic polymerizable compound, a photoacid generator is preferred.

[0277] The photopolymerization initiator in the ink of this invention may contain only one type or two or more types. The photopolymerization initiator may also be a combination of a photoradical initiator and a photoacid generator. The photoradical initiator includes pyrolysis-type radical initiators and hydrogen extraction-type radical initiators.

[0278] Colorants

[0279] The ink used in this invention may also include a colorant if necessary. The colorant may be a dye or a pigment, but a pigment is preferred because it has good dispersibility with the components of the ink and excellent weather resistance.

[0280] Preferably, the pigment is dispersed such that the volume average particle size of the pigment particles is preferably in the range of 0.08 μm to 0.5 μm, the maximum particle size is preferably in the range of 0.3 μm to 10 μm, and more preferably in the range of 0.3 μm to 3 μm. The dispersion of the pigment is adjusted by selecting the pigment, dispersant, and dispersion medium, as well as by adjusting the dispersion conditions and filtration conditions.

[0281] In addition, to improve the dispersibility of the pigment, a dispersant and a dispersing aid may also be included. The total amount of the dispersant and the dispersing aid is preferably in the range of 1 to 50% by mass relative to the pigment.

[0282] The ink used in this invention may also include, as needed, a dispersion medium for dispersing the pigments. A solvent may also be contained within the ink as a dispersion medium, but to suppress solvent residue in the resulting print, it is preferable to use a photopolymerizable compound (a monomer with particularly low viscosity) as the dispersion medium.

[0283] When using dyes, examples include oil-soluble dyes.

[0284] The ink may contain one or more colorants to achieve the desired color. The amount of colorant is preferably in the range of 0.1% to 20% by mass relative to the total amount of ink, and more preferably in the range of 0.4% to 10% by mass.

[0285] Other Ingredients

[0286] The ink used in this invention may also contain other components such as agglomerating agents, surfactants, curing accelerators, coupling agents, and ion scavengers, within the scope of achieving the effects of this invention. These components may be present in the ink in one or more forms. Furthermore, from the viewpoint of curability, solvent-free is preferred, but solvents may be added to adjust the ink viscosity.

[0287] "Properties"

[0288] At the point where the ink fully gels and achieves good pinning properties upon settling and cooling to room temperature, the viscosity of the ink used in this invention at 25°C is preferably 1 Pa·s to 1 × 10⁻⁶ Pa·s. 4 The viscosity of the ink at 80°C is preferably in the range of 3 mPa·s to 20 mPa·s, and more preferably in the range of 7 mPa·s to 9 mPa·s, according to the viewpoint of further improving the ejection performance from the inkjet head.

[0289] The ink used in this invention preferably has a phase transition point in the range of 40°C or higher and less than 100°C. When the phase transition point is 40°C or higher, the ink rapidly gels after adhering to the printing medium, thus further increasing its pinning properties. Furthermore, when the phase transition point is less than 100°C, the ink's processability becomes good and its dispensing stability becomes higher. From the viewpoint of being able to dispense ink at lower temperatures and reduce the load on the image forming apparatus, the phase transition point of this ink is more preferably in the range of 40°C to 60°C.

[0290] From the viewpoint of further improving the ejection performance from the inkjet head, the average dispersed particle size of the pigment particles involved in this invention is preferably in the range of 50 nm to 150 nm, and the maximum particle size is preferably in the range of 300 nm to 1000 nm. The average dispersed particle size is further preferably in the range of 80 nm to 130 nm. The average dispersed particle size of the pigment particles in this invention refers to the value obtained using a Zetasizer ZSP (manufactured by Malvern) via dynamic light scattering. Furthermore, since the ink containing the colorant has a high concentration and light is not transmitted in this measuring instrument, the ink is diluted 200 times before measurement. The measurement temperature is set to room temperature (25°C).

[0291] Formation of Solder Resist Patterns

[0292] The ink used in this invention is preferably a solder resist ink for forming solder resist patterns used in printed circuit boards. When forming solder resist patterns using this ink, moisture can be prevented from penetrating into the solder resist pattern. As a result, the adhesion between the copper foil and the solder resist pattern interface in the printed circuit board becomes good, and copper migration is prevented and insulation degradation is suppressed.

[0293] The method for forming a solder resist pattern using the ink used in this invention preferably includes: (1) the step of ejecting ink from the nozzle of an inkjet head and allowing the ink to fall onto a printed circuit board on which circuitry is formed; and (3) the step of heating the ink to formally cure it.

[0294] When the ink used in this invention contains a compound with photopolymerizable functional groups and a photopolymerization initiator, it is preferable to include a step ((2)) between steps (1) and (3) above, in which the ink is temporarily cured by irradiating it with active light.

[0295] (1) Process:

[0296] In step (1), droplets of the ink of the present invention are ejected from the inkjet head and placed on the printed circuit board, which serves as the printing medium, at positions corresponding to the solder resist pattern to be formed, thus creating a pattern. The ejection method from the inkjet head can be either on-demand or continuous.

[0297] By ejecting ink droplets from the inkjet head while the ink is heated, ejection stability can be improved. The ink temperature during ejection is preferably in the range of 40°C to 100°C, and more preferably in the range of 40°C to 90°C to further improve ejection stability. In particular, ejection is preferably performed at an ink temperature in the range of 7 mPa·s to 15 mPa·s, and more preferably in the range of 8 mPa·s to 13 mPa·s.

[0298] Regarding sol / gel phase transfer inks, to improve ink ejection performance from the inkjet head, it is preferable to set the ink temperature when filling the inkjet head to (gelation temperature + 10) °C to (gelation temperature + 30) °C. When the ink temperature inside the inkjet head is lower than (gelation temperature + 10) °C, ink gels inside the inkjet head or on the nozzle surface, easily reducing ink ejection performance. On the other hand, when the ink temperature inside the inkjet head exceeds (gelation temperature + 30) °C, the ink temperature becomes too high, and the ink composition may sometimes deteriorate.

[0299] There are no particular limitations on the method of heating the ink. For example, at least one of the following can be heated by means of a panel heater, a strip heater, or a heat-insulating liquid: the ink tank constituting the printhead, the supply pipes, the ink supply system including the front chamber ink tank immediately preceding the printhead, the filter-equipped piping, and the piezoelectric head. In terms of printing speed and image quality, the amount of ink droplets ejected is preferably in the range of 2 pL to 20 pL.

[0300] There are no particular limitations on the printed circuit board. For example, copper-clad laminates of all grades (FR-4, etc.) made of materials such as paper phenolic resin, paper epoxy resin, glass cloth epoxy resin, glass polyimide, glass cloth / non-woven epoxy resin, glass cloth / paper epoxy resin, synthetic fiber epoxy resin, fluorinated polyethylene PPO cyanate, etc., are preferred. Other polyimide films, PET films, glass substrates, ceramic substrates, wafer boards, stainless steel plates, etc.

[0301] (2) Process:

[0302] In step (2), the ink that landed in step (1) is irradiated with active light to temporarily cure the ink. The active light can be selected from, for example, electron beams, ultraviolet rays, alpha rays, gamma rays, and X-rays, preferably ultraviolet rays. The ultraviolet irradiation can be performed using, for example, a water-cooled LED manufactured by Phoseon Technology at a wavelength of 395 nm. By using an LED as the light source, poor curing of the ink caused by melting due to the radiant heat of the light source can be suppressed.

[0303] The peak irradiation of the solder resist pattern surface with ultraviolet light having a wavelength in the range of 370 nm to 410 nm is preferably 0.5 W / cm². 2 ~10W / cm 2 Within the range, more preferably 1W / cm 2 ~5W / cm 2 The process is carried out within a certain range. From the viewpoint of suppressing radiant heat from irradiating the ink, the amount of light irradiating the solder resist pattern is preferably less than 500 mJ / cm². 2 The irradiation of the active light is preferably performed for a period of 0.001 seconds to 300 seconds after the ink has fallen, and for the purpose of forming a high-precision solder resist pattern, a period of 0.001 seconds to 60 seconds is more preferred.

[0304] (3) Process:

[0305] In step (3), after the temporary curing in (2), the ink is further heated to achieve formal curing. Regarding the heating method, for example, it is preferable to immerse the ink in an oven set in the range of 110°C to 180°C for 10 to 60 minutes.

[0306] In addition, the ink used in this invention can be used not only as ink for forming solder resist patterns as described above, but also as an adhesive, sealant, circuit protectant, etc. for electronic components.

[0307] In this invention, the location where the solder resist pattern is set is not particularly limited, but as mentioned above, the effect of this invention is particularly significant when it is formed across different components or across components with uneven surfaces.

[0308] 2 Inkjet Printing Unit

[0309] The following describes the functions of the basic structural components of a multi-pass inkjet printing apparatus (also referred to as an "inkjet printing apparatus" or "inkjet recording apparatus") that can be used in this invention.

[0310] Figure 8A and 8B The figures shown are schematic diagrams illustrating an inkjet printing apparatus 1 using a multi-pass method; 8A is a front view, and 8B is a top view.

[0311] The inkjet printing apparatus 1 is a printing apparatus that dispenses ink in a multi-pass manner by overlapping printing with the head 3 going back and forth. It includes a box 2 with the head installed, an X-direction linear stage 4 for moving the box 2, a table 5 for setting the substrate, and a Y-direction linear stage 6 for moving the table 5.

[0312] In the inkjet printing apparatus 1, the head 3 moves in the X direction and the table 5 on which the substrate is set moves in the Y direction, thereby performing printing.

[0313] Additionally, although not shown, the inkjet printing apparatus 1 includes a device for controlling ink ejection from the printhead 3 and a computer for controlling the XY stage. The computer controlling the XY stage controls the operation of the XY stage based on image data.

[0314] In addition, the aforementioned computer has a CPU (Central Processing Unit), ROM (Read-Only Memory), and RAM (Random Access Memory).

[0315] As a printing method in the X direction, the box 2 with the head 3 mounted is mounted on the linear stage 4 in the X direction and the computer controlling the XY stage is used to move it to the desired position.

[0316] In addition, as a printing method in the Y direction, ink is ejected from the head as the substrate moves along the table 5 with the substrate mounted on it in the Y direction. The encoder of the linear stage 6 in the Y direction is linked to the device that controls the ink ejection from the head 3, and ink is ejected at the resolution of image data according to the encoder signal.

[0317] When printing is performed in the X direction at a resolution higher than that of the head, the head moves multiple times in the X direction to perform the printing.

[0318] For example, when printing at 2400 dpi using a single inkjet head with a resolution of 600 dpi, after the head performs a first scan in the Y direction, it moves 10.6 μm (equivalent to one pixel of 2400 dpi) in the X direction and performs a second scan in the Y direction. Then, after the head moves 10.6 μm in the X direction and performs a third scan in the Y direction, it moves 10.6 μm in the X direction and performs a fourth scan in the Y direction to complete the printing process.

[0319] In the above, printing is performed with the conveying direction being only one direction, but there are also cases where printing is performed in both directions (called bidirectional printing).

[0320] Additionally, if the printing area is larger than the head width, the head width is moved in the X direction for printing.

[0321] The inventors further studied the inkjet printing device and discovered that the main scanning direction and the sub-scanning direction of the ink ejection device can also be neither perpendicular to nor parallel to the nozzle array. Whether the ink ejection device and the substrate as the printing medium move to form a pattern or both move to form a pattern, it is difficult for streaks and unevenness to occur.

[0322] The following describes a multi-pass inkjet printing apparatus other than those described above that can be used in this invention.

[0323] The ink ejection device (meaning the same as "head" above) has multiple nozzle holes for ejecting ink. These nozzle holes are preferably arranged in a row, but the nozzle row and the head's main scanning direction (meaning the same as "Y direction" above) and sub-scanning direction (meaning the same as "X direction" above) may not be perpendicular or parallel, and there is no particular limitation.

[0324] Figure 41 This illustrates a printing method where the direction of the nozzle array is not perpendicular or parallel to either the X or Y directions, but rather inclined. An inkjet printing apparatus with an inclined nozzle array can also be used in the pattern forming method of this invention.

[0325] Figure 42 This illustrates a printing method where the direction of the ink ejection device itself is not perpendicular or parallel to the X and Y directions, but rather inclined. By appropriately changing the angle between the ink ejection device and the main scanning direction, the spacing of the formed dots can be altered, thus improving nozzle resolution without the need for an additional ink ejection device. Such an inkjet printing apparatus can also be used in the pattern forming method of this invention.

[0326] In addition, in the inkjet printing apparatus 1 described above, printing is performed by moving the head in the X direction and the substrate in the Y direction. However, inkjet printing apparatuses in which the head moves in the Y direction and the substrate moves in the X direction, inkjet printing apparatuses in which the substrate moves in both the X and Y directions, and inkjet printing apparatuses in which the head moves in both the X and Y directions can also be used in the pattern forming method of the present invention.

[0327] Figure 34 This illustrates a method of printing using the inkjet printing apparatus 1 described above. In the first scan, the printing head is fixed, and as the substrate moves in the direction of the arrow and passes under the printing head, ink droplets are ejected from the printing head. Thus, in the positional relationship between the substrate and the printing head, the printing head moves relative to the substrate in the main scanning direction. In the case of printing at a resolution higher than the resolution of the printing head, in the second scan, the printing head moves in the direction of the arrow, and the substrate moves again in the direction of the arrow to eject ink droplets. This process is repeated until printing is complete.

[0328] exist Figure 33 In the inkjet printing apparatus 100 shown, the printing is performed by mounting the box 2 with the head 3 on the linear stage 6 in the Y direction and using a computer that controls the XY stage to move it to the desired position.

[0329] In addition, as a printing method in the X direction, after printing in the main scanning direction in the Y direction, the table 5 on which the substrate is set moves in the X direction to perform the next printing in the main scanning direction in the Y direction.

[0330] Similar to the inkjet printing unit 1, the encoder of the linear stage 4 located in the X direction is linked to the device that controls the ink ejection from the head 3, and the ink is ejected at the resolution of the image data according to the encoder signal.

[0331] Figure 35 This illustrates a method of printing using an inkjet printing apparatus 100. In scan 1, the ink ejector moves along the main scanning direction on a fixed substrate, ejecting ink droplets. Next, in scan 2, the substrate moves in the direction of the arrow, so that the ink ejector moves relative to the substrate in the sub-scanning direction. Then, on the fixed substrate, the ink ejector moves again along the main scanning direction, ejecting ink droplets. This process is repeated until printing is complete.

[0332] Figure 36This invention illustrates a printing method using an inkjet printing apparatus in which the substrate moves in both the X and Y directions. In scan 1, the printing head is fixed, and the substrate moves in the direction of the arrow, ejecting ink droplets from the head as it passes under the head. Thus, in the positional relationship between the substrate and the head, the head moves relative to the substrate in the main scanning direction. Next, in scan 2, the substrate moves in the direction of the arrow, thus, in the positional relationship between the substrate and the head, the head moves relative to the substrate in the secondary scanning direction. Then, on the fixed substrate, the ink ejection device moves again in the main scanning direction to eject ink droplets. This process is repeated until printing is complete.

[0333] Figure 37 This illustrates a printing method using an inkjet printing apparatus where the head moves in both the X and Y directions. In scan 1, the head moves along the main scanning direction on a stationary substrate, ejecting ink droplets. Next, in scan 2, the head moves in the direction of the arrow, causing the substrate to move again in that direction, ejecting ink droplets once more. This process is repeated until printing is complete.

[0334] In addition, by arranging multiple heads and installing them into the box, the number of scans can be reduced, and the printing time can be shortened.

[0335] Figure 40 This illustrates a method for printing at a resolution of 2400 dpi using four inkjet heads with a nozzle resolution of 600 dpi via segmented printing. The four inkjet heads are staggered and mounted to the cartridge at a spacing that corresponds to a resolution of 2400 dpi.

[0336] like Figure 30A As shown in 30B, when using a single inkjet head with a nozzle resolution of 600 dpi and printing at a resolution of 2400 dpi using four segmented image data, 16 scans are required. However, as... Figure 40 As shown, with four inkjet heads installed in a staggered manner, it is possible to complete the task in one scan. Figure 30A The process involves scanning 1 through 4 times, so printing can be completed in a total of 4 scans, which can shorten the printing time.

[0337] As one of the printing methods using the random multiple-drop method of the present invention, as described above, a method can be described as using a random grayscale image with multiple grayscale values ​​and controlling the liquid volume in accordance with the grayscale or density of each pixel.

[0338] For example, by using Adobe Photoshop to filter noise from a 256-level, 30% grayscale image, it is possible to create something like... Figure 16Random multi-grayscale image data. Based on this image data, ink volume is allocated, for example, with 7 pL for the black portion of grayscale 0–86, 3.5 pL for the gray portion of grayscale 87–172, and 0 pL for the white portion of grayscale 173–255.

[0339] By changing the ejection waveform when ink is ejected from the nozzle or by forming multiple dots for the same pixel, dots can be formed with different liquid volumes corresponding to each pixel.

[0340] For example, with the above liquid volume distribution, using an inkjet head with a liquid volume of 3.5 pL, it is specified that 2 drops are dispensed for the black portion of grayscale 0 to 86, 1 drop is dispensed for the gray portion of grayscale 87 to 172, and no white portion of grayscale 173 to 255, thereby enabling the formation of dots with different liquid volumes.

[0341] As a method for printing using the random multiple-pass method of the present invention, there are methods such as dividing the source image into multiple random non-overlapping images for printing, and using a function such as a random number to make the landing random by utilizing the inkjet ejection control system.

[0342] Image segmentation can be achieved using the following methods. It can be done using image processing software such as Adobe Photoshop 2020. For example, Photoshop can be used to convert a grayscale image to monochrome 2-grayscale using methods like error diffusion, creating a random image of black and white. Next, the tones of this image are inverted to create an inverted black and white image.

[0343] Example

[0344] The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto. In addition, when the terms "parts" or "%" are used in the examples, they respectively represent "parts by mass" or "% by mass" unless otherwise specified.

[0345] Example 1

[0346] [Ink Modulation]

[0347] <Preparation of Pigment Dispersion>

[0348] Place the dispersant and dispersion medium shown below into a stainless steel beaker and heat and stir on a hot plate at 65°C for 1 hour to dissolve. After cooling to room temperature, add the pigment and 200g of 0.5mm diameter zirconia beads into a glass bottle and seal tightly. Disperse the mixture using a paint shaker until the desired particle size is achieved, then remove the zirconia beads.

[0349] (Yellow pigment dispersion)

[0350] Dispersant 1: EFKA7701 (manufactured by BASF) 5.6 parts by weight; Dispersant 2: Solsperse 22000 (manufactured by Lubrizol Corporation, Japan)

[0351] 0.4 parts by weight of dispersion medium: dipropylene glycol diacrylate (containing 0.2% UV-10)

[0352] 80.6 parts by weight of pigment: PY185 (manufactured by BASF, Paliotol Yellow D1155)

[0353] 13.4 parts by weight

[0354] (Blue pigment dispersion)

[0355] Dispersant: EFKA7701 (manufactured by BASF) 7 parts by weight; Dispersion medium: dipropylene glycol diacrylate (containing 0.2% UV-10).

[0356] 70 parts by weight of pigment: PB15:4 (manufactured by Dainippon Seika, Chromofine Blue-6332JC)

[0357] 23 parts by weight

[0358] After mixing the prepared dispersion according to the following proportions, the ink was prepared by filtering it using a 3μm Teflon (registered trademark) membrane filter manufactured by ADVATEC. Furthermore, the viscosity (η1) at the ink ejection temperature of 75°C was 10 mPa·s, and the viscosity (η2) at room temperature (25°C), the landing temperature, was 1 × 10⁻⁶ mPa·s. 4 mPa·s. That is, the viscosity ratio η2 / η1 is 1000. Furthermore, the same ink was used in the examples and comparative examples described below.

[0359]

[0360]

[0361] [Printing of patterns]

[0362] Using a linear XY stage and control system (IJCS-1: Konica Minolta) equipped with one inkjet head (KM1800iSHC-C: Konica Minolta, 600 dpi resolution), a printed pattern was printed onto an optical PET film serving as a substrate under the following conditions: a UV-LED light source with a wavelength of 395 nm and a flow rate of 500 mJ / cm². 2 The printed material is produced by exposing / curing it with irradiation energy. Figure 13 A photograph of an optical microscope taken at 100x magnification of print 1 is shown.

[0363] Printed pattern: The pattern is placed in the four corners of a 70mm x 70mm area. Hollow circles ranging from 100μm to 1000μm

[0364] Image data of the filling section: Refer to Figure 12 (Using Adobe Photoshop 2020's noise filtering to transform 256 grayscale 50% gray to random multi-grayscale gray)

[0365] Resolution: 2400dpi × 3000dpi (transfer direction)

[0366] Number of passes: 4 (600dpi x 4)

[0367] Distance moved along the direction of the nozzle array: 10.6 μm

[0368] Printing method: Block

[0369] Liquid volume distribution: 0-86 gray level 3.5 pL

[0370] 87-255 grayscale 0pL (droplet not provided)

[0371] Ink ejection temperature: 75℃

[0372] Substrate temperature (temperature at which ink falls): Room temperature (25℃)

[0373] Example 2

[0374] Using a linear XY stage and control system (IJCS-1: Konica Minolta) equipped with one inkjet head (KM1800iSHC-C: Konica Minolta, 600 dpi resolution), under the following conditions, via... Figure 14 The 600 dpi head moves 8 times in the conveying direction and 1 time in the head nozzle array direction to print a pattern onto an optical PET film serving as a substrate in a random multiple-pass manner according to a numerical sequence, as shown in an example of this embodiment. A UV-LED light source with a wavelength of 395 nm and a flow rate of 500 mJ / cm² is used. 2 The printed material is produced by exposing / curing it with irradiation energy.

[0375] Printed pattern: placed in the four corners of a 70mm x 70mm area. Hollow circles ranging from 100μm to 1000μm

[0376] Image data of the filling section: Refer to Figure 15

[0377] Resolution: 1200dpi × 1200dpi (transfer direction)

[0378] Number of passes: 8 (600dpi x 4 x 2)

[0379] Distance moved along the direction of the nozzle array: 21.2 μm

[0380] Printing method: Randomly selected

[0381] Liquid volume distribution: 10.5 pL for the entire surface

[0382] Ink ejection temperature: 75℃

[0383] Substrate temperature (temperature at which ink falls): Room temperature (25℃)

[0384] Example 3

[0385] Except for changing the printing conditions to the conditions described below, printed material 3 was produced in the same manner as in Example 1. A 100x optical microscope photograph of printed material 3 is shown below. Figure 17 .in addition, A photograph of a hollow circle under an optical microscope at 100x magnification is Figure 19 .

[0386] Printed pattern: placed in the four corners of a 70mm x 70mm area. Hollow circles ranging from 100μm to 1000μm

[0387] Image data of the hollow circle: Reference Figure 18 (Hollow circle without border)

[0388] Image data of the filling section: Refer to Figure 16 (Using Adobe Photoshop 2020's noise filtering to transform 256 grayscale 30% grayscale into random multi-grayscale grayscale)

[0389] Resolution: 2400dpi × 2400dpi (transfer direction)

[0390] Number of passes: 4 (600dpi x 4)

[0391] Distance moved along the direction of the nozzle array: 10.6 μm

[0392] Printing method: Block

[0393] Liquid volume distribution: 0-86 gray level 7pL

[0394] 87-172 grayscale 3.5pL

[0395] 173-255 grayscale, 0 pL (droplet not provided)

[0396] Example 4

[0397] Except for changing the printing conditions to the conditions described below, printed material 4 is produced in the same manner as in Example 3. Printed material 4... A photograph of a hollow circle under an optical microscope at 100x magnification is Figure 21 .

[0398] Image data of the hollow circle: Figure 20 (The edges of the hollow circle are unified with a grayscale of 155 to make each pixel appear as the same volume.)

[0399] Example 5

[0400] Except for changing the substrate to a glass epoxy board with a Cu wiring pattern of 15 μm thickness and L / S (line / space) = 100 μm / 100 μm, the printed material 5 was produced in the same manner as in Example 3.

[0401] An enlarged schematic diagram of a printed circuit board with added Cu wiring patterns is shown below. Figure 22 The image data printed on it is Figure 23 .

[0402] Example 6

[0403] In addition to image data such Figure 24 Except for changing the amount of one pixel in the part connected to the Cu wiring pattern to 10.5 pL, the printed material 6 was produced in the same manner as in Example 5.

[0404] Example 7

[0405] In addition to image data such Figure 25 Except for changing the amount of one pixel in the part connected to the Cu wiring pattern to 10.5 pL and changing the amount of one pixel around it to 7 pL continuous thickness, the printed material 7 is produced in the same manner as in Example 5.

[0406] Example 8

[0407] Except for changing the printing conditions to the conditions described below, the printed material 8 was produced in the same manner as in Example 5. A 100x optical microscope photograph of the printed material 8 is shown below. Figure 27 .

[0408] Image data of the filling section: Refer to Figure 26 (The 256 grayscale values ​​are transformed into random multi-grayscale values ​​using the same filtering process as described above)

[0409] Resolution: 1200dpi × 1200dpi (transfer direction)

[0410] Number of passes: 2 (600dpi x 2)

[0411] Distance moved along the direction of the nozzle array: 21.2 μm

[0412] Printing method: Block

[0413] Liquid volume distribution: 0-86 gray level 14pL

[0414] 87-172 grayscale 7pL

[0415] 173-255 grayscale, 0 pL (droplet not provided)

[0416] Example 9

[0417] Using a linear XY stage and control system (IJCS-1, Konica Minolta) equipped with one inkjet head (KM1800iSHC-C: Konica Minolta, nozzle resolution 600 dpi), a printed pattern was printed onto an optical PET film serving as a substrate under the following conditions: a UV-LED light source with a wavelength of 395 nm and a flow rate of 500 mJ / cm². 2 The irradiation energy is used to expose / cure the printed material to produce the printed material 11.

[0418] Printed pattern: placed in the four corners of a 70mm x 70mm area. Hollow circles ranging from 100μm to 1000μm

[0419] Image data of the filled area: Figure 31 Reference source image data

[0420] Resolution: 2400dpi × 2400dpi (transfer direction)

[0421] Printing direction (main scanning direction): Unidirectional printing

[0422] Printing direction (sub-scanning direction): forward printing

[0423] Number of passes: 8 (600dpi x 8)

[0424] Distance moved along the direction of the nozzle array: 10.6 μm

[0425] Printing method: Random multiple passes, see reference. Figure 31

[0426] Liquid volume distribution: 3.5 pL for the entire surface

[0427] Ink ejection temperature: 75℃

[0428] Substrate temperature (temperature at which ink falls): Room temperature (25℃)

[0429] Example 10

[0430] [Segmented Printing (Image Segmentation Number 2)]

[0431] Regarding image data, such as Figure 29 As shown, image data of the filling section is segmented using image processing software in a manner that prevents pixels from overlapping during overlapping printing, and in a manner that does not follow the order of the rows and columns in which the pixels are arranged, and does not have a constant periodicity, thus creating segmented image data No.1 and No.2. Then, under the following conditions, each segmented image data is sequentially overlapped and printed.

[0432] Except for changing the image data and printing conditions to the conditions described below, the printed matter 12 is produced in the same manner as in Example 9.

[0433] Printed pattern: placed in the four corners of a 70mm x 70mm area. Hollow circles ranging from 100μm to 1000μm

[0434] Image data of the filled area: Figure 29 Reference source image data

[0435] Number of image segments: 2

[0436] Segmenting image data: Figure 29 Referencing segmented image data

[0437] Resolution: 2400dpi × 2400dpi (transfer direction)

[0438] Number of passes: 8 (600dpi x 8)

[0439] Printing direction (main scanning direction): Unidirectional printing

[0440] Printing direction (sub-scanning direction): forward printing

[0441] Distance moved along the direction of the nozzle array: 10.6 μm

[0442] Printing method: Random multiple passes, see reference. Figure 29

[0443] Liquid volume distribution: 3.5 pL for the entire surface

[0444] Ink ejection temperature: 75℃

[0445] Substrate temperature (temperature at which ink falls): Room temperature (25℃)

[0446] Example 11

[0447] [Segmented Printing (Image Segmentation Number 4)]

[0448] Except for changing the number of image data segments and the printing conditions to the following conditions, the printed matter 13 is produced in the same manner as in Example 10.

[0449] Printed pattern: placed in the four corners of a 70mm x 70mm area. Hollow circles ranging from 100μm to 1000μm

[0450] Image data of the filled area: Figure 30A And 30B, referring to the source image data

[0451] Number of image segments: 4

[0452] Segmenting image data: Figure 30A And 30B, referring to segmented image data

[0453] Resolution: 2400dpi × 2400dpi (transfer direction)

[0454] Number of passes: 16 (600dpi x 16)

[0455] Printing direction (main scanning direction): Unidirectional printing

[0456] Printing direction (sub-scanning direction): forward printing

[0457] Distance moved along the direction of the nozzle array: 10.6 μm

[0458] Printing method: Random multiple passes, see reference. Figure 30A and 30B

[0459] Liquid volume distribution: 3.5 pL for the entire surface

[0460] Ink ejection temperature: 75℃

[0461] Substrate temperature (temperature at which ink falls): Room temperature (25℃)

[0462] Example 12

[0463] [Two-way printing]

[0464] Except for changing the printing conditions to the conditions described below, the printed matter 14 is produced in the same manner as in Example 10.

[0465] Printed pattern: placed in the four corners of a 70mm x 70mm area. Hollow circles ranging from 100μm to 1000μm

[0466] Image data of the filled area: Figure 38 Reference source image data

[0467] Number of image segments: 2

[0468] Segmenting image data: Figure 38 Referencing segmented image data

[0469] Resolution: 2400dpi × 2400dpi (transfer direction)

[0470] Number of passes: 8 (600dpi x 8)

[0471] Printing direction (main scanning direction): bidirectional printing

[0472] Printing direction (sub-scanning direction): forward printing

[0473] Distance moved along the direction of the nozzle array: 10.6 μm

[0474] Printing method: Random multiple passes, see reference. Figure 38

[0475] Liquid volume distribution: 3.5 pL for the entire surface

[0476] Ink ejection temperature: 75℃

[0477] Substrate temperature (temperature at which ink falls): Room temperature (25℃)

[0478] Example 13

[0479] [Reverse printing]

[0480] Except for changing the printing conditions to the conditions described below, the printed matter 15 is produced in the same manner as in Example 10.

[0481] Printed pattern: placed in the four corners of a 70mm x 70mm area. Hollow circles ranging from 100μm to 1000μm

[0482] Image data of the filled area: Figure 39 Reference source image data

[0483] Number of image segments: 2

[0484] Segmenting image data: Figure 39 Referencing segmented image data

[0485] Resolution: 2400dpi × 2400dpi (transfer direction)

[0486] Number of passes: 8 (600dpi x 8)

[0487] Printing direction (main scanning direction): Unidirectional printing

[0488] Printing direction (sub-scanning direction): Mixed forward and reverse printing

[0489] Distance moved along the direction of the nozzle array: 10.6 μm

[0490] 21.2 μm (between 3 and 4 scans, between 7 and 8 scans)

[0491] Printing method: Random multiple passes, see reference. Figure 39

[0492] Liquid volume distribution: 3.5 pL for the entire surface

[0493] Ink ejection temperature: 75℃

[0494] Substrate temperature (temperature at which ink falls): Room temperature (25℃)

[0495] Example 14

[0496] [Random dripping multiple times passing method combined with random multiple passing method]

[0497] Using a linear XY stage and control system (IJCS-1, Konica Minolta) equipped with one inkjet head (KM1800iSHC-C: Konica Minolta, nozzle resolution 600 dpi), a printed pattern was printed onto an optical PET film serving as a substrate under the following conditions: a UV-LED light source with a wavelength of 395 nm and a flow rate of 500 mJ / cm². 2 The irradiation energy is used to expose / cure the printed material to produce the printed material.16

[0498] In addition, liquid volume is allocated in accordance with the grayscale of each pixel in the image data to produce the printed material 16.

[0499] Printed pattern: placed in the four corners of a 70mm x 70mm area. Hollow circles ranging from 100μm to 1000μm

[0500] Image data of the filled area: Figure 43 Referring to the image data (using the noise filtering function of Adobe Photoshop 2020 to transform 256 grayscale 30% grayscale into random multi-grayscale grayscale),

[0501] Resolution: 2400dpi × 2400dpi (transfer direction)

[0502] Number of passes: 8 (600dpi x 8)

[0503] Printing direction (main scanning direction): Unidirectional printing

[0504] Printing direction (sub-scanning direction): forward printing

[0505] Distance moved along the direction of the nozzle array: 10.6 μm

[0506] Printing method: Random multiple passes, see reference. Figure 43

[0507] Liquid volume distribution: 0-86 gray level 7pL

[0508] 87-172 grayscale 3.5pL

[0509] 173-255 grayscale, 0 pL (droplet not provided)

[0510] Ink ejection temperature: 75℃

[0511] Substrate temperature (temperature at which ink falls): Room temperature (25℃)

[0512] Example 15

[0513] [Segmentation printing on the printing substrate (image segmentation number 2)]

[0514] Except for changing the substrate to a glass epoxy board with a Cu wiring pattern of 15 μm thickness and L / S (line / space) = 100 μm / 100 μm, the printed material 17 was produced in the same manner as in Example 10.

[0515] Comparative Example 1

[0516] Except for changing the printing conditions to the conditions described below, the printed material 9 was produced in the same manner as in Example 1. A 100x optical microscope photograph of the printed material 9 is shown below. Figure 28 .

[0517] Printed pattern: placed in the four corners of a 70mm x 70mm area. Hollow circles ranging from 100μm to 1000μm

[0518] Image data of the filling section: Refer to Figure 15

[0519] Resolution: 2400dpi × 2400dpi (transfer direction)

[0520] Number of passes: 4 (600dpi x 4)

[0521] Distance moved along the direction of the nozzle array: 10.6 μm

[0522] Printing method: Block

[0523] Liquid volume distribution: 3.5 pL for the entire surface

[0524] Comparative Example 2

[0525] Except for changing the substrate to a glass epoxy board with a Cu wiring pattern of 15 μm thickness and L / S (line / space) = 100 μm / 100 μm, the printed material 10 was produced in the same manner as in Comparative Example 1.

[0526] An enlarged schematic diagram of a printed circuit board with added Cu wiring patterns is shown below. Figure 22 The image data printed on it is Figure 23 .

[0527] Comparative Example 3

[0528] Except for changing the printing conditions to the conditions described below, the printed matter 18 is produced in the same manner as in Example 10.

[0529] Printed pattern: placed in the four corners of a 70mm x 70mm area. Hollow circles ranging from 100μm to 1000μm

[0530] Image data of the filled area: Figure 44 Reference source image data

[0531] Number of image segments: 2

[0532] Segmenting image data: Figure 44 Referencing segmented image data

[0533] Resolution: 2400dpi × 2400dpi (transfer direction)

[0534] Number of passes: 8 (600dpi x 8)

[0535] Printing direction (main scanning direction): Unidirectional printing

[0536] Printing direction (sub-scanning direction): forward printing

[0537] Distance moved along the direction of the nozzle array: 10.6 μm

[0538] Printing method: interlaced, see reference Figure 44

[0539] Liquid volume distribution: 3.5 pL for the entire surface

[0540] Ink ejection temperature: 75℃

[0541] Substrate temperature (temperature at which ink falls): Room temperature (25℃)

[0542] [evaluate]

[0543] <Evaluation of streaks>

[0544] The occurrence of streaks is evaluated by visually confirming the pattern in the printed material.

[0545] ◎: No streak observed

[0546] 〇: Although I could feel a slight streaking sensation, it was at a level I didn't mind.

[0547] △: I can feel the streaks.

[0548] ×: Streaks were clearly noticeable

[0549] <Glossiness>

[0550] Using a handheld gloss meter (PG-II: manufactured by Nippon Denshoku Kogyo Co., Ltd.), gloss was measured up to 60 degrees in both directions parallel and perpendicular to the transport direction. In the presence of streaks, the gloss values ​​varied significantly in the parallel and perpendicular directions; in the absence of streaks, the values ​​in the parallel and perpendicular directions were approximately the same. When the gloss difference between the parallel and perpendicular directions exceeded 3, the streaks became noticeable.

[0551] <Average film thickness>

[0552] The average film thickness was calculated by measuring five points: the four corners and the center of the 70mm x 70mm printed pattern area using a film thickness gauge (Digimicro MH-15M+TC-101A: Nikon).

[0553] <Pinhole>

[0554] The printed pattern is observed using an optical microscope to evaluate the presence of pinholes. The presence of localized pinholes can sometimes compromise the adhesion of the substrate.

[0555] <Pattern Formation>

[0556] Observation using an optical microscope Hollow circles are used to evaluate pattern formation.

[0557] ◎: The outline of the hollow circle roughly reproduces the printed image.

[0558] 〇: There are slight bumps and depressions in the outline of the hollow circle, but this does not pose a problem as a pattern-forming property.

[0559] △: The hollow circle outline has many bumps and depressions, resulting in a deterioration in pattern formation.

[0560] ×: The outline of the hollow circle is destroyed, and a pattern cannot be formed.

[0561] The following evaluation is made regarding Examples 5 to 8, which used a printed substrate, and Comparative Example 2.

[0562] <Tightness>

[0563] In the printed pattern area, a checkerboard pattern is made according to the cross-cut method of JIS K5600. Adhesive tape is then applied and removed to observe the adhesion and residual state of the printed pattern and evaluate the adhesion.

[0564] ◎: Adhesion residue rate 100%

[0565] 〇: Adhesion residue rate is above 80% and less than 100%.

[0566] △: Adhesion residue rate is 60% or higher but less than 80%.

[0567] ×: Adhesion residue rate is less than 60%.

[0568] Solder tolerance

[0569] After immersing the printed pattern in a 260°C solder bath for 10 seconds three times, markings were made in a checkerboard pattern on the printed pattern area according to the cross-cutting method of JISK5600. Adhesive tape was then applied and removed to observe the adhesion and residue of the printed pattern and evaluate the solder resistance.

[0570] ◎: Adhesion residue rate 100%

[0571] 〇: Adhesion residue rate is above 80% and less than 100%.

[0572] △: Adhesion residue rate is 60% or higher but less than 80%.

[0573] ×: Adhesion residue rate is less than 60%.

[0574] <Staircase following>

[0575] After immersing three times in a 260°C solder bath for 10 seconds each, checkerboard patterns were made using the JIS K5600 cross-cutting method, spanning both areas with and without Cu wiring patterns. Adhesive tape was then applied and removed to observe the peeling of the printed pattern and evaluate adhesion. Adhesion deteriorated in the stepped areas of the Cu wiring pattern when the film thickness thinned.

[0576] ◎: No peeling occurs in the stepped areas of the Cu pattern.

[0577] 〇: Fine linear peeling was observed in the stepped portion of the Cu pattern.

[0578] 〇△: Continuous linear peeling was observed in the stepped portion of the Cu pattern.

[0579] △: Peeling becomes significant in the stepped areas where the Cu pattern is located, exposing the Cu surface.

[0580] ×: Peeling across the entire surface in the stepped portion of the Cu pattern.

[0581] The experimental conditions and evaluation results are presented in Tables I and II.

[0582] [Table 1]

[0583]

[0584] [Table 2]

[0585]

[0586] As can be seen from the evaluation results shown in Tables I and II above, the patterns formed by the pattern forming method of the present invention are superior to the comparative examples in the above evaluation items.

[0587] Regarding the random multiple-pass printing method, it is known that by performing segmented printing, bidirectional printing, or mixed forward and reverse printing, streaks and unevenness are further reduced, and pattern formation is further improved. Furthermore, it is known that by applying a random dripping multiple-pass method within the random multiple-pass printing process, streaks and unevenness are reduced.

[0588] Industrial availability

[0589] Through the above-described means of the present invention, a pattern forming method using inkjet printing can be provided that is highly precise and free of streaks or unevenness, has uniform insulation and conductivity properties when using inks containing functional materials such as insulators and conductors, and has good coating adhesion.

[0590] Symbol Explanation

[0591] 1 Inkjet printing device

[0592] 2 boxes

[0593] 3 heads

[0594] 4 X-axis linear stage

[0595] 5 tables

[0596] 6 Y-direction linear stage

[0597] 7 Printing substrate

[0598] 8. Copper wiring section (height 15μm, width 100μm)

[0599] 9. Ink ejection device

[0600] 10. Substrate (printing medium)

[0601] 100 Inkjet Printing Unit

Claims

1. A pattern forming method using an inkjet printing method based on patterned image data, characterized by, in a manner in which a substrate as a printing medium is moved a plurality of times and droplets of ink are ejected from nozzles of an ink ejection device having a plurality of nozzle holes to the substrate as the printing medium to form the pattern, controlling in such a manner that: the amount of liquid of the ink used in the formation of a coating film of a dot constituting the pattern formed on the substrate is not constant periodically from a dot adjacent to the dot, and the coating film as a whole of the pattern is not uniform, in the pattern forming method, controlling in such a manner that, for a substrate having a convex portion, the amount of liquid of a dot of a face of an edge of an outer side of a boundary of an inner side and the outer side of a bottom face of the convex portion is continuously varied from the face of the bottom face to the face of the outer side in the outer side direction.

2. The pattern forming process according to claim 1, wherein controlling in such a manner that: the amount of liquid of the ink used in the formation of a coating film of a dot constituting the pattern formed on the substrate is not constant periodically from a dot adjacent to the dot, and the coating film as a whole of the pattern is not uniform.

3. The pattern forming method according to claim 1 or 2, characterized by, in a part of the pixels of the image data constituting the pattern, no droplets of the ink are ejected. controlling in such a manner that:

4. The pattern forming process according to claim 1 or 2, wherein the difference in the amount of liquid of the ink per 1 dot of a dot of an edge of an inner side of a pattern portion forming a boundary of the pattern portion and a non-pattern portion formed on the substrate is within ± 5%. controlling in such a manner that:

5. The pattern forming process according to claim 1 or 2, wherein for a substrate having a convex portion, the difference in the amount of liquid of the ink per 1 dot of a dot of an edge of the convex portion is within ± 5%. controlling in such a manner that:

6. The pattern forming process according to claim 1 or 2, wherein the average thickness of a coating film of a dot constituting the pattern is 15 μm or more.

7. The pattern forming method according to claim 1 or 2, characterized by, the amount of liquid of the ink landed in order to form a coating film of each dot constituting the pattern is changed a plurality of times.

8. The pattern forming method according to claim 1 or 2, characterized by, as the ink, an ink of any of a hot-melt type, a gelation type, or a thixotropic type is used.

9. The pattern forming method according to claim 1 or 2, characterized by, as the ink, a solder resist ink is used.

10. A pattern forming method using an inkjet printing method based on patterned image data, characterized by, in a manner in which a substrate as a printing medium is moved a plurality of times and droplets of ink are ejected from nozzles of an ink ejection device having a plurality of nozzle holes to the substrate as the printing medium to form the pattern, controlling in such a manner that: the amount of liquid of the ink used in the formation of a coating film of a dot constituting the pattern formed on the substrate is not constant periodically from a dot adjacent to the dot, and the coating film as a whole of the pattern is not uniform, the position of the dot on which the droplet lands is not in the order in which rows and columns of pixels constituting the image data are arranged, and is not constant periodically, ​ In the pattern forming method, for a substrate having a convex shape portion, the liquid amount of a point of a surface of an edge of an outer side of a boundary between an inner side and an outer side of a bottom surface of the convex shape portion is continuously changed from a surface in contact with the convex shape portion to a surface in the outer side direction.

11. The pattern forming process according to claim 10, wherein The control is performed in such a manner that: The difference in the liquid amount of ink per 1 point of a point of a surface of an edge of an inner side of a pattern portion forming a boundary between the pattern portion and a non-pattern portion formed on the substrate is within ±5%.

12. The pattern forming process according to one of claims 10, wherein The control is performed in such a manner that: For a substrate having a convex shape portion, the difference in the liquid amount of ink per 1 point of a point of an edge of the convex shape portion is within ±5%.

13. The pattern forming process according to one of claims 10, wherein The control is performed in such a manner that: The average thickness of a coating film of a point constituting the pattern is 15 μm or more.

14. The pattern forming method according to claim 10, wherein The liquid amount of the ink landing for forming a coating film of each point constituting the pattern is changed a plurality of times.

15. The pattern forming method according to claim 10, wherein As the ink, an ink of any of a hot-melt type, a gelation type, or a thixotropic type is used.

16. The pattern forming method according to claim 10, wherein As the ink, a solder resist ink is used.

17. A pattern forming method using an inkjet printing method based on pattern-based image data, wherein In a manner in which an ink ejection device having a plurality of nozzle holes or a substrate as a printing medium is moved a plurality of times and droplets of ink are ejected from the nozzle of the ink ejection device to the substrate as the printing medium to form the pattern, the control is performed in such a manner that: The landing of the droplets of the ink used in the formation of a coating film of a point constituting the pattern formed on the substrate is performed a plurality of times, and The positions of the points at which the droplets land do not have constant periodicity in the main scanning direction and the sub-scanning direction of the ink ejection device, and are discontinuous in the main scanning direction, In the pattern forming method, for a substrate having a convex shape portion, the liquid amount of a point of a surface of an edge of an outer side of a boundary between an inner side and an outer side of a bottom surface of the convex shape portion is continuously changed from a surface in contact with the convex shape portion to a surface in the outer side direction.

18. The pattern forming method according to claim 17, wherein The image data of the pattern is divided into a plurality of pieces in such a manner that the pixels do not overlap in the case of overlapping printing, and in such a manner that the positions of the points at which the droplets land do not have constant periodicity in the main scanning direction and the sub-scanning direction of the ink ejection device, and are discontinuous in the main scanning direction, The divided image data is sequentially printed in overlapping fashion.

19. The pattern forming method according to claim 17 or 18, wherein The ink ejection device relatively moves back and forth in the main scanning direction, Droplets of ink are ejected in both the outward and return strokes.

20. The pattern forming method according to claim 17 or 18, wherein The ink ejection device relatively moves in combination of the forward direction and the reverse direction with respect to the sub-scanning direction.

21. The pattern forming process according to one of claims 17 or 18, wherein The control is performed in such a manner that: The amount of the ink used in forming the coating film of the dots constituting the pattern formed on the substrate is not constant periodically with respect to the dots adjacent to each other, and is not uniform as a whole of the coating film of the pattern, in correspondence with the gray scale or density of each pixel of the image data constituting the pattern.

22. The pattern forming process according to one of claims 17 or 18, wherein The control is performed in such a manner that: The difference in the amount of the ink per 1 dot of the dots forming the edge inside the pattern portion of the boundary between the pattern portion and the non-pattern portion formed on the substrate is within ±5%.

23. The pattern forming process according to one of claims 17 and 18, wherein The control is performed in such a manner that: For a substrate having a convex shape portion, the difference in the amount of the ink per 1 dot of the dots forming the edge of the convex shape portion is within ±5%.

24. The pattern forming process according to one of claims 17 or 18, wherein The control is performed in such a manner that: The average thickness of the coating film of the dots constituting the pattern is 15 μm or more.

25. The pattern forming method according to claim 17 or 18, wherein The amount of the ink landing for forming the coating film of each dot constituting the pattern is changed a plurality of times.

26. The pattern forming method according to claim 17 or 18, wherein As the ink, an ink of any one of a hot-melt type, a gelation type, or a thixotropic type is used.

27. The pattern forming method according to claim 17 or 18, wherein As the ink, a solder resist ink is used.

28. A pattern forming method using an inkjet printing method based on pattern-based image data, wherein In a manner in which a substrate as a printing medium is moved a plurality of times and droplets of ink are ejected from nozzles of an ink ejection device having a plurality of nozzle holes to the substrate as the printing medium to form the pattern, the control is performed in such a manner that: The amount of the ink used in forming the coating film of the dots constituting the pattern formed on the substrate is not constant periodically with respect to the dots adjacent to each other, and is not uniform as a whole of the coating film of the pattern, in correspondence with the gray scale or density of each pixel of the image data constituting the pattern. In the pattern forming method, for a substrate having a convex shape portion, the amount of the ink per 1 dot of the dots forming the edge of the outer side of the boundary between the inner side and the outer side of the bottom surface of the convex shape portion is more than that of the dots forming the edge of the convex shape portion.

29. A pattern forming method using an inkjet printing method based on pattern-based image data, wherein In a manner in which a substrate as a printing medium is moved a plurality of times and droplets of ink are ejected from nozzles of an ink ejection device having a plurality of nozzle holes to the substrate as the printing medium to form the pattern, the control is performed in such a manner that: The landing of the droplets of the ink used in forming the coating film of the dots constituting the pattern formed on the substrate is performed a plurality of times, and The positions of the dots where the droplets land are not in the order in which the rows and columns of each pixel constituting the image data are arranged, and are not constant periodically, In the pattern forming method, the control is performed in such a way that, for a substrate with a convex shape, the amount of ink at each point on the outer edge of the boundary between the inner and outer sides of the bottom surface forming the convex shape is increased compared to the point on the edge of the convex shape.

30. A method for forming a pattern based on pattern image data using inkjet printing, characterized in that, In a method where an ink ejection device having multiple nozzle orifices or a substrate serving as a printing medium is moved multiple times to eject ink droplets from the nozzles of the ink ejection device onto the substrate serving as the printing medium to form the pattern, control is performed in the following manner: The ink droplets used in the formation of the coating film constituting the dots of the pattern formed on the substrate are dropped multiple times, and The position of the point where the droplet lands does not have a constant periodicity in the main scanning direction and the sub-scanning direction of the ink ejection device, and is discontinuous in the main scanning direction. In the pattern forming method, the control is performed in such a way that, for a substrate with a convex shape, the amount of ink at each point on the outer edge of the boundary between the inner and outer sides of the bottom surface forming the convex shape is increased compared to the point on the edge of the convex shape.

31. An inkjet printing apparatus for forming a pattern based on image data of a design, characterized in that, A pattern is formed by the pattern forming method according to any one of claims 1, 2, 10, 17, and 18.

Images