TWI848485B - Pattern forming method and inkjet printing device - Google Patents

Abstract

The subject of the present invention is to provide a pattern forming method that does not produce streaks and has good reproducibility, and an inkjet printing device for forming the pattern. The pattern forming method of the present invention is characterized in that: in a method 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 ink droplets are ejected from the nozzles of the ink ejection device to the substrate as the printing medium to form the aforementioned pattern, the hits of the aforementioned ink droplets used in forming the coating of the dots (dots) constituting the aforementioned pattern formed on the aforementioned substrate cover a plurality of times. The position of the aforementioned point where the aforementioned droplet hits is controlled in a pattern portion other than the boundary portion in a manner that is not in accordance with the order of rows and columns in which the pixels constituting the image data are arranged and does not have a certain periodicity, and is controlled in a continuous or periodic manner in accordance with the order of the long side direction in which the pixels constituting the image data are arranged at the aforementioned boundary portion.

Description

Pattern forming method and inkjet printing device

The present invention relates to a pattern forming method and an inkjet printing device. More specifically, the present invention relates to a pattern forming method for forming a pattern without streaks and with good reproducibility, and an inkjet printing device for forming the pattern.

In recent years, research and development of technology for "forming patterns of electronic devices by an inkjet printing method using ink containing functional materials (hereinafter also simply referred to as "inkjet method")" has been carried out.

Patent document 1 discloses a method for manufacturing a multilayer wiring substrate having an interlayer insulating film produced by a droplet ejection method (inkjet method). However, in this method, there arises a problem that "bulge may occur depending on the combination of the substrate and the ink" or "when forming a pattern across different substrates, the ink may flow to the side of the substrate with higher wettability due to the difference in wettability of each substrate with respect to the ink."

Therefore, Patent Document 2 discloses a method of "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, if the wetting characteristics of each substrate are greatly different, there is a problem of ink flow. Moreover, even when the pattern is formed across a substrate with uneven surfaces, there is a problem of ink flow.

For this reason, in Patent Document 3 disclosed in the invention of the present inventor, the viscosity of the ink during the injection and after the injection in the pattern formation of the insulating layer by the inkjet method is stipulated, and the above-mentioned problem is sought to be solved thereby. However, the insulating layer forming ink with a phase change mechanism used has a high dot fixity after injection, and therefore it can be inferred that the occurrence of streak-like unevenness in the scanning direction can still be further improved.

In addition, Patent Document 4 states the following: That is, in a one-pass printer of an inkjet method, a plurality of adjacent pixels are grouped as one group, and the amount of droplets ejected at a certain pixel in the group is adjusted to reduce the number of pixels ejected in the one group, thereby suppressing gloss streaks in the conveying direction. However, according to the inventor's review, it was found that if this method is applied in a multi-pass method, streaks in a direction orthogonal to the conveying direction will be found.

When high resolution is required for high-precision pattern printing, a multi-pass method is mainly used. However, the time between each pass of the multi-pass printing is long, and streak-like unevenness is prone to occur. In addition, streak-like unevenness not only affects the appearance, but also causes insulation unevenness or conductivity unevenness when forming an insulating film or a conductive film, which is a big problem. [Prior technical literature] [Patent literature]

[Patent Document 1] Japanese Patent Publication No. 2003-309369 [Patent Document 2] Japanese Patent Publication No. 2010-231287 [Patent Document 3] International Publication No. 2015/002316 [Patent Document 4] Japanese Patent Publication No. 2012-162057

[The problem the invention is trying to solve]

The present invention is made in view of the above-mentioned problems and conditions, and its solution is to provide a method for forming a pattern that does not produce streaks and has good reproducibility, and an inkjet printing device for forming the pattern. [Means for solving the problem]

The inventor of the present invention has examined the causes of the above problems in order to solve the above problems. As a result, it has been found that by setting the position of the point (dot) where the droplet hits to be random (a state that is considered random or unpredictable without overall uniformity or regularity such as periodicity) in the pattern part other than the boundary part, and controlling the boundary part in a continuous or periodic manner, it is possible to form a pattern that does not produce streaks and has good reproducibility, and the present invention has been completed. That is, the above problems of the present invention are solved by the following means.

1. A pattern forming method is a pattern forming method by inkjet printing based on image data of a pattern, characterized in that: In a method 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 ink droplets are ejected from the nozzles of the ink ejection device to the substrate as a printing medium to form the aforementioned pattern, The hits of the aforementioned ink droplets used in forming the coating of dots constituting the aforementioned pattern formed on the aforementioned substrate cover a plurality of hits, and, The positions of the aforementioned dots where the aforementioned droplets hit are controlled in a pattern portion other than a boundary portion in a manner that is not in accordance with the order of rows and columns in which the pixels constituting the aforementioned image data are arranged and that does not have a certain periodicity, At the aforementioned boundary, the control is performed in a continuous or periodic manner according to the order of the long side direction in which the pixels constituting the aforementioned image data are arranged.

2. A pattern forming method is a pattern forming method by inkjet printing based on image data of the pattern, characterized in that: In a method 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 ink droplets are ejected from the nozzles of the ink ejection device to the substrate as a printing medium to form the aforementioned pattern, The hits of the aforementioned ink droplets used in forming the coating of the dots (dots) constituting the aforementioned pattern formed on the aforementioned substrate cover a plurality of hits, and, The positions of the aforementioned dots where the aforementioned droplets hit are controlled in a pattern portion other than the boundary portion in a manner that is not continuous or periodic in the main scanning direction of the aforementioned ink ejection device, At the aforementioned boundary, the control is performed in a continuous or periodic manner according to the order of the long side direction in which the pixels constituting the aforementioned image data are arranged.

3. A pattern forming method as described in item 2, wherein the position of the aforementioned point where the aforementioned droplet hits is controlled at the aforementioned pattern portion other than the aforementioned boundary portion in a manner that is not continuous or periodic in the secondary scanning direction of the aforementioned ink ejection device.

4. A pattern forming method as described in any one of items 1 to 3, wherein the formation of the coating at the aforementioned points at the aforementioned boundary portion is completed earlier than the formation of the coating at the aforementioned points at the aforementioned pattern portion other than the aforementioned boundary portion.

5. A method for forming a pattern as described in any one of items 2 to 4, wherein the image data of the aforementioned pattern is divided into a plurality of pieces in such a manner that the pixels do not overlap each other when the aforementioned droplets are printed in an overlapping manner and the positions of the aforementioned points where the aforementioned droplets hit are not continuous or periodic in the aforementioned main scanning direction of the aforementioned ink ejection device, and the aforementioned image data that have been divided are printed in an overlapping manner in sequence.

6. A pattern forming method as described in any one of items 2 to 5, wherein the ink ejection device is relatively moved back and forth in the main scanning direction, and ink droplets are ejected in both the forward path and the return path.

7. A pattern forming method as described in any one of items 1 to 6, wherein the ink used is an ink having a ratio η2/η1 of 100 or more between a viscosity η1 at a temperature when ejected and a viscosity η2 at a temperature when hit.

8. The pattern forming method as recited in any one of Items 1 to 7, wherein the ink used is a hot melt type, a gel type, or a thixotropy type ink.

9. The pattern forming method as described in any one of Items 1 to 8, wherein solder resist ink is used as the ink.

10. An inkjet printing device is an inkjet printing device that forms a pattern based on image data of the pattern, and its characteristics are: The pattern is formed by a pattern forming method described in any one of items 1 to 9. [Effect of the invention]

By means of the above-mentioned means of the present invention, it is possible to provide a pattern forming method for forming a pattern without streaks and with good reproducibility, and an inkjet printing device for forming the pattern.

Although the mechanism of the effect or action of the present invention is not yet fully understood, it can be inferred that it is as follows.

After repeated examinations, the inventors of the present invention have learned that: in a multi-pass method 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 ink droplets are ejected from the nozzles of the ink ejection device to the substrate as the printing medium to form a pattern, by controlling the position of the point where the droplets hit, (I) in a manner that is not in accordance with the order of rows and columns in which the pixels constituting the image data are arranged and does not have a certain periodicity, (II) in a manner that is not continuous or periodic in the main scanning direction of the ink ejection device, That is, by setting it as a random multi-pass method, it is possible to print a high-precision pattern with high resolution.

The pattern forming method by the inkjet printing method of the present invention is described in comparison with the pattern forming method of the prior art. For example, a method is described in which an inkjet head with a resolution of 600 dpi is used to print image data by moving the inkjet head in the direction of the nozzle row and performing multiple passes so that the output resolution becomes 1200 dpi.

The inkjet printing method shown in Figure 1 is called a block method, and in the first scan in the transport direction, the same nozzle is used for printing, and the nozzle is moved in the nozzle row direction by a distance (21.2μm) of an output resolution of 1200dpi, and the 1200dpi printing is completed in the second scan. In this case, as shown in Figure 1, the droplet hits continuously in the "first scan" and "second scan" as shown in the figure, and streaks are likely to occur in the transport direction.

The inkjet printing method shown in the second figure is called an interleaving method, and in the first scan in the transport direction, the same nozzle skips one pixel at a time to print, and in the second scan in the transport direction, the pixels between the parts printed in the first scan are printed, and then the nozzle is moved in the nozzle row direction by the distance (21.2μm) of the output resolution of 1200dpi, and the third and fourth prints are performed in the same way, so that the printing with an output resolution of 1200dpi is completed. In this case, as shown in the figure, the hitting order is cyclical, such as "1st scan" to "4th scan", and streaks are likely to occur.

The inkjet printing method shown in FIG. 3 is the "random multiple-pass method" of the present invention, which is a so-called "random" hit method. In a way that the hit order becomes random, 1200dpi printing is completed by a total of 8 passes. In addition, the number of passes can also be set to more. In addition, the number of jumps in the conveying direction can be further increased to increase the number of passes. By using the random multiple-pass method, since the droplets are hit randomly, the streaks become inconspicuous.

In the present invention, the term "random" refers to a state in which the positional relationship between points in a pattern forming method "presupposes that the conditions described below are controlled" is considered to be random or unpredictable because the relationship between the positions of the points does not have overall identity or regularity such as periodicity. Specifically, for example, it refers to the state shown in FIG. 3.

As can be inferred from the comparative example above, it can be imagined that by setting the impact location and order of the ink droplets to be random, there is no periodicity between adjacent pixels or dots in the printed image, and overall it becomes difficult to produce streaks or unevenness.

After further repeated examinations, the inventors of the present invention found that, although the use of the random multiple times method can make it difficult for streaks or unevenness to occur in the pattern portion, it is difficult to reproduce a pattern like the image data at the boundary between the pattern portion and the non-pattern portion. That is, for example, even if the boundary of the pattern in the image data is a straight line, it is actually difficult to form a high-precision straight line at the boundary of the pattern, and there is still room for further improvement.

In view of this, after repeated examinations, the inventors of the present invention have found that by using the above-mentioned random multiple times method mainly for the pattern portion, and controlling the relative positional relationship of dots near the boundary between the pattern portion and the non-pattern portion so that it has continuity or periodicity, the reproducibility of the pattern can be improved.

The pattern forming method of the present invention is a pattern forming method by inkjet printing based on image data of the pattern, and is characterized in that: In a method 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 ink droplets are ejected from the nozzles of the ink ejection device to the substrate as a printing medium to form the aforementioned pattern, The hit of the aforementioned ink droplets used in forming the coating of the dots (dots) constituting the aforementioned pattern formed on the aforementioned substrate covers a plurality of hits, and, The position of the aforementioned dot where the aforementioned droplet hits is controlled in the pattern portion other than the boundary portion in a manner that is not in accordance with the order of rows and columns in which the pixels constituting the aforementioned image data are arranged and does not have a certain periodicity, At the aforementioned boundary, the control is performed in a continuous or periodic manner according to the order of the long side direction in which the pixels constituting the aforementioned image data are arranged.

Furthermore, it is a method for forming a pattern by inkjet printing based on image data of a pattern, characterized in that: In a method 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 ink droplets are ejected from the nozzles of the ink ejection device to the substrate as a printing medium to form the aforementioned pattern, The hits of the aforementioned ink droplets used in forming the coating of the dots (dots) constituting the aforementioned pattern formed on the aforementioned substrate cover a plurality of hits, and, The position of the aforementioned dot where the aforementioned droplet hits is controlled in a pattern portion other than the boundary portion in a manner that is not continuous or periodic in the main scanning direction of the aforementioned ink ejection device, At the aforementioned boundary, the control is performed in a continuous or periodic manner according to the order of the long side direction in which the pixels constituting the aforementioned image data are arranged. This feature is a common or corresponding technical feature in the following implementation forms.

As an implementation form of the present invention, from the perspective of suppressing the occurrence of streaks in the pattern, it is more ideal to control the position of the aforementioned point where the aforementioned droplet hits the aforementioned pattern portion other than the aforementioned boundary portion, and further in a manner that is not continuous or periodic in the secondary scanning direction of the aforementioned ink ejection device.

From the perspective of obtaining good pattern reproducibility, it is ideal to complete the formation of the coating at the aforementioned points at the aforementioned boundary portion earlier than the formation of the coating at the aforementioned points at the aforementioned pattern portion other than the aforementioned boundary portion.

From the perspective of suppressing the occurrence of streaks in the pattern, it is more ideal to divide the aforementioned image data of the aforementioned pattern into multiple numbers in such a way that the pixels will not overlap with each other when overlapping printing is performed and the positions of the aforementioned points where the aforementioned droplets hit are not continuous or periodic in the main scanning direction of the aforementioned ink ejection device, and to overlap and print the aforementioned image data in sequence after the division.

From the perspective of shortening the time required for pattern formation, it is more ideal to make the ink ejection device relatively move back and forth in the main scanning direction and eject ink droplets in both the forward and return paths.

From the viewpoint of improving pattern formation properties, it is ideal to use as the aforementioned ink an ink in which the ratio η2/η1 between the viscosity η1 at the temperature when ejected and the viscosity η2 at the temperature when hit is 100 or more.

From the viewpoint of improving pattern formation, it is ideal to use a hot melt type, a gel type, or a thixotropy type ink as the aforementioned ink.

From the perspective of application that matches the purpose of the invention, for example, from the perspective of being able to solve the problem of protecting a circuit pattern with an insulating film, it is more ideal to use a solder resist ink as the ink.

The inkjet printing device of the present invention can form a pattern by using the pattern forming method of the present invention.

The present invention and its constituent elements, as well as forms and aspects for implementing the present invention are described in detail below. In addition, in this application, the term "to" is used to include the numerical values described before and after it as lower limits and upper limits.

≪Overview of the pattern forming method of the present invention≫ The pattern forming method of the present invention is a pattern forming method by inkjet printing based on image data of a pattern, and is characterized in that: In a method of forming a pattern by moving an ink ejection device having a plurality of nozzle holes or a substrate as a printing medium a plurality of times and ejecting droplets of ink from the nozzles of the ink ejection device to the substrate as a printing medium, The hit of the droplets of the ink used in forming the coating of the dots (dots) constituting the aforementioned pattern formed on the aforementioned substrate covers a plurality of hits, and, The position where the droplets are made to hit the aforementioned dots, In the pattern portion other than the boundary portion, (I) Control is performed in a manner that is not in accordance with the order of rows and columns in which the pixels constituting the image data are arranged and does not have a certain periodicity, (II) Control is performed in a manner that is not continuous or periodic in the main scanning direction of the ink ejection device, and at the boundary, control is performed in a manner that is continuous or periodic in accordance with the order of the long side direction in which the pixels constituting the image data are arranged.

That is, by setting the position of the point where the droplet hits to be random (not having overall uniformity or regularity such as periodicity and being considered random or unpredictable) in the pattern portion other than the boundary portion, and controlling the boundary portion to be continuous or periodic, it is possible to form a high-precision pattern without streaks or spot-like unevenness and with good reproducibility. In addition, when using ink containing functional materials such as insulators or conductors, it is possible to form a pattern with uniform insulation properties or conductive properties and good coating adhesion.

In the present invention, "having continuity or periodicity" means that when a droplet hits and forms a dot coating, the coating has continuity to the extent that it can be visually seen. When the position of the dot is continuous without any gaps and covers a wide range, the coating of the dot formed by the droplet hitting the position is continuous to the extent that it can be visually seen. Moreover, even if there are gaps, if the gaps are extremely narrow (for example, 1 to 2 points) and cover a wide range and are periodic, the coating of the dot formed by the droplet hitting the position will be continuous to the extent that it can be visually seen. On the contrary, when the interval is wide, even if it is periodic, the continuity will not be able to be visually observed.

Therefore, in the pattern part other than the boundary part, even if the positions of the points where the droplets hit are not continuous without intervals within a range of, for example, 2 to 5 points, the continuity of the coating formed by the droplets hitting at the positions is difficult to be visually observed. Therefore, if the range is so narrow that it cannot be visually observed, even if the positions of the points where the droplets hit are partially continuous, sufficient randomness can be obtained. However, the number of points here is only an example and is not absolutely limited to this.

In the present invention, the so-called "pattern part" refers to a place where a pattern (the narrow meaning described below) is formed, and the so-called "non-pattern part" refers to a place where no pattern is formed. In addition, in the present invention, the so-called "pattern" refers to a coating formed on a substrate using ink in a narrow sense, and refers to the entirety of multiple coatings formed on a substrate in a broad sense.

Furthermore, the so-called "boundary portion" refers to the collection of "coatings of points located near the boundary between the pattern portion and the non-pattern portion" among the coatings of points constituting the pattern portion, and at least includes coatings of points that contribute to the formation of the boundary between the pattern portion and the non-pattern portion (hereinafter also referred to as "boundary forming portion").

A detailed explanation is provided using drawings. Figure 5 is a diagram showing an example of a pattern of the present invention in which four blank corners are arranged in the four corners, and one grid corresponds to one dot coating.

The area marked with symbol 11 represents a "non-pattern portion" where no pattern is formed, the areas marked with symbols 12, 13 and 14 represent a "pattern portion" where a pattern is formed, and the line marked with symbol 15 represents a "boundary between the pattern portion and the non-pattern portion." However, in reality, the boundary 15 between the pattern portion and the non-pattern portion does not have an area.

The area marked with symbols 12 and 13 (the area marked with symbol 16) located near the boundary 15 between the pattern part and the non-pattern part represents the "boundary part" defined above, and the area marked with symbol 14 represents the "pattern part other than the boundary part".

The area marked with symbol 12 represents the "boundary forming portion" which is "a collection of coating dots that contribute to the formation of the boundary between the pattern portion and the non-pattern portion", and must be included in the boundary portion 16. On the other hand, the area marked with symbol 13 represents the "boundary portion other than the boundary forming portion", which does not necessarily need to be included in the boundary portion 16, but may or may not exist. The boundary portion 13 other than the boundary forming portion is located adjacent to the boundary forming portion 12.

In the present invention, the so-called "dot" refers to the smallest unit of pixel constituting the ink image formed on the printing medium by the inkjet printing method, and refers to the coating portion formed by one droplet of ink. Therefore, the pixel in the ink image corresponding to "one pixel in the image data of the printing object" may also be formed by a plurality of dots (droplets).

[1 Pattern forming method at pattern portion other than boundary portion] The pattern forming method of the present invention is characterized in that the position of the aforementioned point where the aforementioned droplet hits is controlled at the pattern portion other than the boundary portion in the present invention, (I) in a manner that is not in accordance with the order of rows and columns in which the pixels constituting the aforementioned image data are arranged and does not have a certain periodicity, and (II) in a manner that is not continuous or periodic in the main scanning direction of the aforementioned ink ejection device.

As mentioned above, in the pattern part other than the boundary part, by setting the position of the point where the droplet hits to random (not having overall uniformity or regularity such as periodicity and being considered as random or unpredictable), that is, by using a random multiple-time method, a highly precise pattern without streaks or spots can be formed.

In the present invention, the method that satisfies the above control condition (I) is called "random multiple method (A)", and the method that satisfies the above control condition (II) is called "random multiple method (B)".

The control condition (I) is a condition that "the position of the point where the droplet hits is set to be random based on the viewpoint of the arrangement of each pixel constituting the image data". In addition, the control condition (II) is a condition that "the position of the point where the droplet hits is set to be random based on the viewpoint of the scanning direction of the ink ejection device". That is, the control conditions (I) and (II) are set from different viewpoints for the condition of "the position of the point where the droplet hits is set to be random". The following is a detailed description of the random multiple methods (A) and (B).

[1.1 Random multiple-shot method (A)] In the random multiple-shot method (A), the position of the point where the droplet hits is controlled in a manner that is not in the order of rows and columns in which the pixels constituting the image data are arranged and does not have a fixed periodicity.

Although the following is an explanation of one example of the implementation form of the pattern forming method caused by the random multiple method (A) of the present invention, it is not limited to the implementation form and aspect of the following example. As long as the above-mentioned control condition (I) is met, it is included in the technical scope of the present invention.

Figure 4 is a diagram showing the image data used in the random multiple-pass method (A), where each dot is formed by a uniform amount of liquid. In addition, multi-level random image data such as Figure 6 can be used to form each dot with a different amount of liquid. In this case, the amount of liquid at the dot is changed corresponding to the level or concentration of each pixel. In addition, the same image data can also be used in the random multiple-pass method (B) described later.

The ink hitting in this embodiment is explained based on the viewpoint of the random multiple-shot method (A). In one scan, dots are formed in a manner that "the dots are hit non-continuously and with intervals in the direction of the rows and columns where the pixels constituting the image data are arranged, and the intervals are not fixed." For the second and subsequent scans, dots are formed in the same manner at positions where dots are not formed, and the dots are not repeated. The number of dots formed in each scan may not be constant. In addition, the number of scans may be further increased.

The printing method in this embodiment is described below from the perspective of the random multiple-pass method (A).

FIG. 11 shows a method for printing 1200 dpi by random hits using one inkjet head with a resolution of 600 dpi. The pattern formation by the random multiple-pass method (A) in the present embodiment shown in FIG. 3 is formed by scanning the inkjet head four times in the Y direction (transportation direction) as shown in FIG. 11, and then moving the inkjet head 21.2 μm (equivalent to one pixel of 1200 dpi) in the X direction and scanning the inkjet head four times in the Y direction, thereby completing the printing with a total of eight passes (for the device, refer to FIG. 8A and FIG. 8B).

[1.2 Random multiple method (B)] In the random multiple method (B), the position of the point where the droplet hits is controlled in a manner that is neither continuous nor periodic in the main scanning direction of the ink ejection device.

Although the following is an explanation of one example of the implementation form of the pattern forming method caused by the random multiple method (B) of the present invention, it is not limited to the implementation form and aspect of the following example. As long as the above-mentioned control condition (II) is met, it is included in the technical scope of the present invention.

Regarding the image data, the image data used in the random multiple-shot method (A) can be used as described above.

The ink hitting in this embodiment is explained from the perspective of the random multiple-shot method (B). In one scan, dots are formed in a manner that "does not have continuity or periodicity in the main scan direction, but are hit with intervals, and the intervals are not constant." For the second and subsequent scans, dots are formed in the same manner at positions where dots are not formed, and the dots are not repeated. The number of dots formed in each scan may not be constant. In addition, the number of scans may be further increased.

The printing method in this embodiment is described below from the perspective of the random multiple-pass method (B).

FIG. 11 shows a method for printing 1200 dpi by random hits using one inkjet head with a resolution of 600 dpi. Here, the Y direction is set as the main scanning direction, and the X direction is set as the sub-scanning direction.

The pattern formation caused by the random multiple-pass method (B) in this embodiment shown in FIG. 3 is formed by making the inkjet head print by scanning 4 times in the Y direction as shown in FIG. 11, and then moving it 21.2 μm (equivalent to 1 pixel of 1200 dpi) in the X direction and scanning 4 times in the Y direction again, thereby completing the printing with a total of 8 moves (passes) (for the device, please refer to FIG. 8A and FIG. 8B).

In the above method, although the "direction of the rows and columns of pixels in the image data" and the "main scanning direction and sub-scanning direction at the ink ejection device" are parallel, they do not absolutely need to be parallel and may be non-parallel.

FIG. 7 shows an example of a situation where the direction of the rows and columns of pixels in the image data is not parallel to the main scanning direction and the sub-scanning direction of the ink ejection device. For example, the portion marked with an ellipse in FIG. 7 is not continuous in the direction of the rows and columns of pixels in the image data, but it can be said to be continuous in the main scanning direction of the ink ejection device. Therefore, the printing method of the portion marked with an ellipse in FIG. 7 conforms to the random multiple method (A) and does not conform to the random multiple method (B).

In addition, from the viewpoint of forming a high-precision pattern without streaks or spots, it is more ideal to be a printing method that meets both the random multiple methods (A) and (B).

Furthermore, in the random multiple-pass method (B), it is ideal to control in a manner that does not have continuity or periodicity in the sub-scanning direction.

As described in the above printing method, in the multiple-pass method, after the ink ejection device is moved in the main scanning direction and covers the main scanning direction multiple times to make the droplets hit, it is moved in the sub-scanning direction, and then moved in the main scanning direction to cover the droplets hit multiple times. Therefore, if the droplets are continuously hit at "the positions of two adjacent points in the main scanning direction", the time difference between the coating of the two points will become extremely short.

On the other hand, if the structure is such that droplets are continuously hit at "the positions of two adjacent points in the sub-scanning direction", the ink ejection device will become "after the droplet hits the position of the first point, moves in the main scanning direction and completes the hitting of the droplet in the main scanning direction, then moves in the sub-scanning direction, and then moves in the main scanning direction to hit the position of the second point". Therefore, the time difference in the formation of the coating of the two points will become longer than that in the main scanning direction. Therefore, when the positions of the points where the droplets hit are continuous in the main scanning direction, streaks or spot-like unevenness are more likely to occur than when they are continuous in the sub-scanning direction.

Therefore, in the random multiple-shot method (B), the position of the point where the droplet hits is controlled in a manner that is neither continuous nor periodic in the main scanning direction of the ink ejection device. Although a high-precision pattern without streaks or spots can be formed, this effect can be further enhanced by further controlling the position of the point where the droplet hits in a manner that is neither continuous nor periodic in the main scanning direction of the ink ejection device.

[1.3 Split printing] As an implementation form of the present invention, it is also ideal if the aforementioned image data of the aforementioned pattern is configured to be "split into a plurality of pieces in such a manner that the pixels do not overlap each other when overlapping printing is performed and the positions of the aforementioned points where the aforementioned droplets hit are not continuous or periodic in the main scanning direction of the aforementioned ink ejection device, and the aforementioned image data before the splitting is sequentially overlapped and printed".

In the present invention, the printing method that meets the above control conditions is called "division printing".

Although the following is an example of the implementation form of the pattern forming method by the split printing of the present invention, it is not limited to the implementation form and mode of the following example, and as long as the above control conditions are met, it is included in the technical scope of the present invention. In addition, in the following illustration, although the example of "split printing is applied to the pattern part other than the boundary part of the present invention" is shown, as long as the above control conditions at the boundary part are met, it can be applied even at the boundary part of the present invention.

FIG. 29 shows a method of using a single inkjet head with a nozzle resolution of 600 dpi to print at a resolution of 2400 dpi by random hits and segmented printing. In FIG. 29, although source image data in which each dot is formed by a uniform amount of liquid is used, it is also possible to use multi-level random source image data as in FIG. 6 to form each dot with a different amount of liquid.

In the split printing, the source image data is split into two and the split image data are produced. After that, each of the split image data is printed in sequence in an overlapping manner. Therefore, the split image data is produced in such a way that the pixels do not overlap each other when the overlapping printing is performed. In addition, the split image data is produced in such a way that the position of the point where the droplet hits does not have continuity or periodicity in the main scanning direction of the ink ejection device.

Segmented image data can be created using image processing software such as Adobe's Photoshop 2020. For example, a grayscale image is converted into black and white using Photoshop using the error diffusion method, and a random image of white and black is created. Then, the image is toned and an image with reversed black and white is created. The two images obtained are segmented images of black data that are random and do not overlap each other.

Below, split printing is explained by comparing Figure 29, Figure 30A, Figure 30B, and Figure 31. Figure 31 shows a method of using a single inkjet head with a nozzle resolution of 600dpi to print at a resolution of 2400dpi by random hits. In this method, printing is completed in each of the main scanning directions.

In FIG. 31, printing in the main scanning direction is completed by two consecutive scans, for example, the first scan and the second scan. On the other hand, in split printing, as shown in FIG. 29, it is completed by two non-consecutive scans, the first scan and the fifth scan.

In this way, in split printing, since the time required until the printing in the main scanning direction is completed becomes longer, the ink is easily fixed, and the flow of ink can be suppressed, and streaks and unevenness become less likely to occur.

FIG. 30A and FIG. 30B show a method of dividing the source image data into four parts and performing the same divided printing as FIG. 29. In this case, the printing in the main scanning direction is completed by four non-continuous scans, namely the 1st scan, the 5th scan, the 9th scan and the 13th scan.

In this way, by increasing the number of divisions of the source image data, the number of scans until printing is completed in the main scanning direction increases, so the time until printing is completed becomes longer, making it more difficult for streaks and unevenness to occur, and the surface roughness can be reduced.

In addition, during the period until printing in the main scanning direction, printing is also performed in the sub-scanning direction. Therefore, even when using ink with a high viscosity at the time of hitting or an ink with a fast phase change time, the ink is difficult to be fixed in the linear shape of the main scanning direction, and streaks and unevenness are difficult to occur. Furthermore, by increasing the number of scans, the occurrence of "hit deviation caused by the interaction between adjacent hits and previously hit ink droplets (dots)" can be reduced, and pattern formation is improved.

In this embodiment, the so-called "random hitting" means that the position of the point where the droplet hits is controlled in a manner that is neither continuous nor periodic in the main scanning direction of the ink ejection device.

FIG. 32 shows a method of performing split printing similar to that of FIG. 29, but in the first scan and the fifth scan, the positions of the points where the droplets ejected from the nozzle at the left end and the nozzle at the center hit are the same.

The "streaks and unevenness" that the present invention aims to solve are easy to occur if the position of the point where the droplets hit is continuous or periodic in the main scanning direction, but are difficult to occur even if it is continuous or periodic in the sub-scanning direction. Therefore, even if the positions of the points where the droplets ejected from different nozzles hit are made the same in a part of the scanning as shown in FIG. 32, the occurrence of streaks and unevenness can be sufficiently suppressed.

[1.4 Bidirectional printing] As an implementation form of the present invention, it is also ideal if the ink ejection device is configured to relatively move back and forth in the aforementioned main scanning direction and eject ink droplets in both the forward path and the return path.

In the present invention, the printing method that meets the above control conditions is called "bidirectional printing".

Although the following is an example of the implementation form of the pattern forming method by bidirectional printing of the present invention, it is not limited to the implementation form and mode of the following example, and as long as the above control conditions are met, it is included in the technical scope of the present invention. In addition, in the following illustration, although the example of "bidirectional printing is applied to the pattern part other than the boundary part of the present invention" is shown, as long as the above control conditions at the boundary part are met, it can be applied even at the boundary part of the present invention.

FIG. 38 shows a method of bidirectional printing in which the ink ejection device relatively moves back and forth in the main scanning direction and ejects ink droplets in both the forward path and the return path. In FIG. 38, although split printing is performed, split printing is not absolutely necessary.

In the first scan, the ink ejection device moves relatively in the direction of the arrow while ejecting ink droplets (forward movement). Then, in the second scan, the ink ejection device moves relatively in the direction of the arrow so as to form a row of dots on the right side adjacent to the row of dots formed by the first scan, and moves relatively in the direction of the arrow while ejecting ink droplets (return movement). This action is repeated, and printing is completed by a total of 8 scans.

In addition, the so-called "relative movement" in this embodiment may mean that only one of the ink ejection device and the substrate as the printing medium is moved, or both are moved, and refers to "relatively moving the ink ejection device in the positional relationship between the ink ejection device and the substrate as the printing medium."

Therefore, in the first scan of Figure 38, the substrate can be fixed and the ink ejection device can be moved in the direction of the arrow, or the ink ejection device can be fixed and the substrate can be moved in the direction opposite to the arrow.

In the unidirectional printing as shown in FIG. 29, the ink ejection device relatively moves back and forth in the main scanning direction, but it ejects ink droplets only on the forward path and only moves on the return path. Therefore, by performing bidirectional printing, the printing time can be shortened and productivity is improved.

[1.5 Front and back mixed printing] As an implementation form of the present invention, it is also ideal if the ink ejection device is moved relatively in the secondary scanning direction in a combination of the forward direction and the reverse direction.

In the present invention, the printing method that meets the above control conditions is called "front and back mixed printing".

Although the following is an example of the implementation form of the pattern forming method by the front and back mixed printing of the present invention, it is not limited by the implementation form and mode of the following example, as long as the above control conditions are met, it is included in the technical scope of the present invention. In addition, in the following illustration, although the example of "applying the front and back mixed printing to the pattern part other than the boundary part of the present invention" is shown, as long as the above control conditions at the boundary part are met, it can be applied even at the boundary part of the present invention.

FIG. 39 shows a method of performing mixed printing of both front and back sides by moving the ink ejection device in a combination of the forward direction and the reverse direction relative to the secondary scanning direction. In addition, although split printing is performed in FIG. 39, split printing is not absolutely necessary.

In the first scan, the ink ejection device moves relatively in the main scanning direction and ejects ink droplets. Next, in the second scan, the ink ejection device moves relatively in the arrow direction so as to form a dot row with a spacing of one dot to the right of the dot row formed by the first scan, and further moves in the main scanning direction, and ejects ink droplets. Thereafter, in the third scan, the ink ejection device moves relatively in the arrow direction so as to form a dot row between the dot row formed by the first scan and the dot row formed by the second scan, and further moves in the main scanning direction, and ejects ink droplets. This process is repeated 8 times in total to complete the printing.

In the normal printing of the general "relative movement direction of the ink ejection device is only one direction" shown in FIG. 29, since dots are further formed adjacent to the formed dots, depending on the situation, adjacent dots may be formed before the ink of the dots is fixed, which may cause streaks or unevenness. On the other hand, in the positive and negative mixed printing, since dots are formed with a space between the formed dots, adjacent dots are formed after the ink of the dots is fixed, and streaks or unevenness are less likely to occur. Furthermore, in front and back mixed printing, since dots are formed with spaces between them, the occurrence of "hit deviation due to the interaction between adjacent hits and previously hit ink (dots)" can be reduced, and pattern formation is improved.

[2 Pattern forming method at the boundary] The pattern forming method of the present invention is characterized in that the position of the aforementioned point where the aforementioned droplet hits is controlled at the boundary in the present invention, in a continuous or periodic manner according to the order of the long side direction in which each pixel constituting the aforementioned image data is arranged.

As mentioned above, by controlling the boundary in a continuous or periodic manner, a pattern with good reproducibility can be formed.

Although the following is an explanation of one example of the implementation form of the method for forming a pattern at the boundary portion of the present invention, it is not limited to the implementation form and aspect of the following example. As long as the above-mentioned control conditions are met, it is included in the technical scope of the present invention.

As mentioned above, in the present invention, the so-called "boundary portion" refers to the collection of "coatings of points located near the boundary between the pattern portion and the non-pattern portion" among the coatings of points constituting the pattern portion, and at least includes coatings of points that contribute to the formation of the boundary between the pattern portion and the non-pattern portion (hereinafter also referred to as "boundary forming portion").

FIG. 9 shows an example of the pattern of the present invention, and FIG. 10 shows an example of its boundary. When the non-pattern portion 11 has an area corresponding to a plurality of dots, the boundary 16 is formed linearly along the boundary between the non-pattern portion and the pattern portion. FIG. 12 shows the image data used in forming the boundary shown in FIG. 10. Here, one dot corresponds to one pixel constituting the image data.

In the image data corresponding to the boundary portion 16, the pixels are similarly arranged in a line. In the present invention, the so-called "long side direction of the arrangement of the pixels constituting the image data" refers to the direction along the "line formed by connecting the arranged pixels", and is indicated by the direction of the arrow in Figure 12.

Furthermore, as shown in FIG. 12, when the area of the non-pattern portion 11 is extremely small, the boundary portion 16 may not be formed in a linear shape. In this case, in the corresponding image data, the direction in which each pixel is adjacent is regarded as "the long side direction in which each pixel constituting the image data is arranged", and control is performed in a manner of "having continuity or periodicity in the order in which each pixel is adjacent".

FIG. 9 shows an example of forming a pattern by surrounding a non-pattern portion. The image data corresponding to the boundary portion 16 shown in FIG. 10 and the boundary portion 16 shown in FIG. 12 are linear and have a shape in which the ends of the line are closed. However, the boundary portion and the image data corresponding thereto are not absolutely limited to this shape, and may also have a shape in which the ends of the line are not closed.

In one example of the boundary portion described above, although the boundary portion is constituted only by the boundary forming portion, the boundary portion may further include a coating at a point located near the boundary between the pattern portion and the non-pattern portion. One example is shown in FIG. 13.

FIG. 13 shows an example of a case where the boundary portion 16 is a coating (boundary portion other than the boundary forming portion) 13 including dots located near the boundary between the pattern portion and the non-pattern portion in addition to the boundary forming portion 12, and FIG. 14 shows image data used in forming the boundary portion shown in FIG. 13. Here, one dot corresponds to one pixel constituting the image data.

The border portion is preferably a uniform width and is a region along the border between the pattern portion and the non-pattern portion. The "width" here refers to the length (number of points) in the vertical direction relative to the border between the pattern portion and the non-pattern portion.

For example, regarding the boundary portion 16 shown in FIG. 10 , the width can be regarded as the amount of “one dot”, and regarding the boundary portion 16 shown in FIG. 13 , the width can be regarded as the amount of “two dots”.

FIG. 15 shows an example of patterns and their borders. In FIG. 15, the left end shows each pattern, the center shows a border of "one dot" in width in the pattern, and the right end shows a border of "two dots" in width in the pattern.

Although there is no particular restriction on the width of the border, from the perspective of pattern reproduction, it is ideal for the border to have no streaks. The number of points for the width is ideally in the range of 1 to 3.

Hereinafter, the pattern forming method at the boundary portion will be described using the pattern example (rectangle) shown in Fig. 16. Fig. 17 shows image data corresponding to the pattern example (rectangle) shown in Fig. 16.

The pixels constituting the image data are arranged in parallel with respect to the row and column directions, and the row and column directions of the pixels in the image data are parallel to the main scanning direction and the sub-scanning direction at the ink ejection device. Therefore, for the pattern forming method shown below, the position of the point where the droplet hits can be controlled in a continuous or periodic manner according to the order of the long side direction in which the pixels constituting the image data are arranged by continuously or periodically making the ink droplets hit in the main scanning direction and the sub-scanning direction of the ink ejection device.

In addition, the pixels constituting the image data do not need to be arranged in parallel with respect to the row and column directions, and the row and column directions of the pixels in the image data do not need to be parallel to the main scanning direction and the sub-scanning direction at the ink ejection device.

FIG. 18 shows one example of a printing method (block method) for a pattern case (rectangle) at a boundary portion. In addition, by continuously (block method) making ink droplets hit in the main scanning direction and the sub-scanning direction of the ink ejection device, the position of the point where the droplets hit is controlled in a continuous manner according to the order of the long side direction in which the pixels constituting the image data are arranged.

After the ink droplets are continuously hit in the main scanning direction by the first scan, the machine moves in the sub-scanning direction and continuously hits the ink droplets in the sub-scanning direction by the second and third scans. Thereafter, the ink droplets are continuously hit in the main scanning direction by the fourth scan, and printing is completed.

In this printing method, since it has continuity in the main scanning direction and continuity and periodicity in the sub-scanning direction, it is possible to form a straight line with high precision.

In this printing method, although the landing of droplets at the positions of adjacent dots in the sub-scanning direction is performed by the same nozzle, it can also be performed by different nozzles.

FIG. 19 shows one example of a printing method (block method) for a pattern example (rectangle) at a boundary portion (using different nozzles). Similarly, by continuously (block method) making ink droplets hit in the main scanning direction and the sub-scanning direction of the ink ejection device, the position of the point where the droplets hit is controlled in a continuous manner according to the order of the long side direction in which the pixels constituting the image data are arranged. However, in the method shown in FIG. 19, the hitting of droplets at the positions of adjacent points in the sub-scanning direction is performed by different nozzles.

In the method shown in FIG. 19, in the first scan, ink droplets are ejected from the nozzles 26, 27 and 28 (see FIG. 20) and move in the sub-scanning direction, and then, in the second scan, ink droplets are ejected from the nozzles 25, 26 and 27. In this way, in the sub-scanning direction, the ink droplets ejected from each nozzle are sequentially hit.

By using this printing method, although the number of times may increase and the printing time may be prolonged, even if a problem such as a deflection of the hit line occurs at the nozzle, the impact can be reduced.

Figures 21 and 22 show one example of a printing method (interweaving method) for a pattern case (rectangle) at a boundary portion. In addition, by periodically (interweaving method) making ink droplets hit in the main scanning direction and the sub-scanning direction of the ink ejection device, the position of the point where the droplets hit is controlled in a periodic manner according to the order of the long side direction in which the pixels constituting the image data are arranged.

Regardless of the printing method, the image data is divided into two and the aforementioned divided printing is performed. In the method shown in FIG. 21, after the printing is completed based on the first divided image data, the printing is completed based on the second divided image data. In the method shown in FIG. 22, the printing based on the first divided image data and the printing based on the second divided image data are performed in parallel. Specifically, after a scan is performed based on the first divided image data, a scan is performed based on the second divided image data. This is repeated to complete the printing.

Regardless of the printing method, since it is periodic in the main scanning direction and the sub-scanning direction, it is possible to form a straight line with high precision. However, the method shown in Figure 22 can further shorten the time required until the coating of adjacent points is formed, so it is possible to form a straight line with higher precision.

Specifically, for example, in the straight line pattern portion formed at the left end, in the method shown in FIG. 21, printing is completed by the first scan and the fifth scan, but in the method shown in FIG. 22, printing is completed by the first scan and the second scan. Therefore, the method shown in FIG. 22 can further shorten the time required until the coating film of the adjacent points is formed.

In the present invention, the printing method at the border can be a block method or an interweaving method. By using the block method, a straight line with extremely high precision can be formed in the main scanning direction, and by using the interweaving method, a straight line with high precision can be formed in either the main scanning direction or the sub-scanning direction.

For comparison, FIG. 23 shows one example of the printing method (the aforementioned random multiple printing method) for the pattern case (rectangle) at the border. In other words, FIG. 23 shows a situation where "the pattern forming method is not changed at the border and at the pattern parts other than the border, and all are formed by the random multiple printing method."

In the method shown in FIG. 23, although it is also possible to form straight lines without any practical problems, when the above-mentioned block method or interweaving method is used, straight lines with higher precision can be formed.

Next, the case where "the pixels constituting the image data are not arranged in parallel with respect to the row and column directions" is explained. However, "the row and column directions of the pixels in the image data" and "the main scanning direction and the sub-scanning direction at the ink ejection device" are assumed to be parallel.

FIG. 24 is a diagram showing one example of a printing method (block method) for a pattern case (diamond) at a boundary. In addition, even when the pixels constituting the image data are not arranged in parallel with respect to the row and column directions, the position of the point where the droplet hits is similarly controlled in a continuous or periodic manner according to the sequence of the long side direction in which the pixels constituting the image data are arranged.

After the ink droplets are hit in the main scanning direction by the first scan, the ink droplets are moved in the sub-scanning direction and are hit in the main scanning direction by the second scan. At this time, the droplets are hit at positions adjacent to the positions of the points where the droplets were hit in the first scan. Similarly, the droplets are hit at positions adjacent to the positions of the points where the droplets were hit in the first scan in the third and fourth scans.

FIG. 51 shows one example of a printing method (block method) for a pattern case (cucumber shape) at a boundary. In this way, even when the pixels constituting the image data at the boundary are not arranged in parallel with respect to the row and column directions and are visually recognized as a curve, the droplets are made to hit the positions adjacent to the positions of the points where the droplets hit in the previous scan, and the control is performed in a continuous or periodic manner in accordance with the order of the long side direction in which the pixels constituting the image data are arranged.

In addition, FIG. 52 shows an example of a printing method (block method, segmented printing) for a pattern case (gourd shape) at the border. In this way, even when the pixels constituting the image data at the border are not arranged in parallel with the row and column directions and are visually recognized as curved lines, segmented printing can be used.

In this way, even when the pixels constituting the image data are not arranged in parallel with respect to the row and column directions, by making the droplet hit a position adjacent to the point where the droplet hits, it is possible to control in a continuous manner according to the order of the long side direction in which the pixels constituting the image data are arranged.

For comparison, FIG. 25 shows one example of a printing method (random multiple printing method) for a pattern case (diamond) at a boundary. In addition, the position of the point where the droplet hits is set to be random in the long direction of the arrangement of each pixel constituting the image data. In the method shown in FIG. 25, although a straight line can be formed without any practical problems, by using the method shown in FIG. 24, a straight line with high precision can be formed.

[3 Pattern forming method] The following describes a pattern forming method that combines a pattern forming method at a pattern portion other than a boundary portion and a pattern forming method at a boundary portion.

The pattern forming method of the present invention is preferably such that the formation of the coating at the aforementioned points at the aforementioned boundary portion is completed earlier than the formation of the coating at the aforementioned points at the aforementioned pattern portion other than the aforementioned boundary portion.

As such pattern forming methods, there are two methods: a method of first completing pattern formation at the boundary and then performing pattern formation at pattern portions other than the boundary (pattern forming method A), and a method of simultaneously starting pattern formation at the boundary and pattern formation at pattern portions other than the boundary and completing pattern formation at the boundary first (pattern forming method B).

In the present invention, from the perspective of being able to form high-precision straight lines at the boundary and having good pattern reproducibility, the method of first completing pattern formation at the boundary and then performing pattern formation at pattern portions other than the boundary (pattern forming method A) is ideal.

Hereinafter, the pattern forming method by segmentation printing will be described using the image data shown in Fig. 26. In addition, as mentioned above, it is generally desirable to increase the number of segments for the pattern portion other than the boundary portion, but it is desirable to reduce the number of segments for the boundary portion.

In FIG. 26, the segmented image data α is image data corresponding to "the pattern formed at the boundary portion", and the segmented image data β and γ are image data obtained by dividing the image data corresponding to "the pattern formed at the pattern portion other than the boundary portion" into two.

FIG. 27A and FIG. 27B are for showing a method of first completing pattern formation at the boundary and then performing pattern formation at pattern portions other than the boundary (pattern formation method A). The segmented image data No. 1 to No. 3 are equivalent to the segmented image data α to γ described above, and the printing is completed in the order of the segmented image data No. 1 to No. 3.

FIG. 28 shows a method (pattern forming method B) for simultaneously starting pattern formation at the boundary and pattern formation at pattern portions other than the boundary, and completing pattern formation at the boundary first. The segmentation data α and β are set as one segmentation image data No. 1, and the segmentation image data γ is set as segmentation image data No. 2, and printing is completed in the order of segmentation image data No. 1 to No. 2.

For comparison, FIG. 43 shows a method (pattern forming method C) in which pattern formation at the pattern portion other than the boundary portion is started first and pattern formation at the boundary portion and pattern formation at the pattern portion other than the boundary portion are completed simultaneously. The segmented data β is set as segmented image data No. 1, and the segmented image data α and γ are set as one segmented image data No. 2, and printing is completed in the order of segmented image data No. 1 to No. 2.

In addition, Figures 44 and 45 show a method (pattern forming method D) for simultaneously starting pattern formation at the boundary portion and pattern formation at the pattern portion other than the boundary portion and completing them simultaneously.

Regardless of which of the pattern forming methods A to D is used, it is the same that a straight line with high precision can be formed at the boundary and the pattern reproducibility is good. However, from the perspective of being able to obtain a higher effect, it is ideal to use the pattern forming method A or B, and it is more ideal to use the pattern forming method A.

In addition, a method of "first completing the pattern formation at the pattern portion other than the boundary portion, and then performing the pattern formation at the boundary portion" can also be considered. In this method, a high-precision straight line can be formed, and the pattern reproducibility is good. However, from the perspective of being able to obtain a higher effect, it is ideal to use the pattern forming method A or B, and it is more ideal to use the pattern forming method A.

In addition, as a comparison, FIG. 46 shows a method of forming all the pattern portions at the boundary and other than the boundary by random multiple times without changing the pattern forming method. In this method, a straight line can be formed at the boundary, which is not a practical problem, but a higher effect can be obtained by using the pattern forming method of the present invention.

In the pattern forming method described above, the image data (divided image data α) used in the pattern forming at the boundary portion is arranged so that each pixel constituting the image data is arranged in parallel with respect to the row and column directions, but it is not limited to this. In FIG. 47, the pattern forming method is shown for the case where "each pixel constituting the image data corresponding to the pattern forming at the boundary portion is not arranged in parallel with respect to the row and column directions".

FIG. 47 shows a method (pattern forming method B) for simultaneously starting pattern formation at the boundary (diamond) and pattern formation at pattern portions other than the boundary, and completing pattern formation at the boundary first. As shown in FIG. 47, even when "the pixels constituting the image data corresponding to the pattern formation at the boundary are not arranged in parallel with respect to the row and column directions", the pattern forming method described above can be used to form a pattern.

In addition, in the pattern forming method of the present invention, the liquid volume of the hit droplets can be the same or different, and the liquid volume of the hit droplets can be changed at the boundary portion and the pattern portion other than the boundary portion.

For example, when a pattern is formed on a substrate having projections and depressions, by increasing the amount of liquid droplets hitting the depressions or the periphery of the depressions, the pattern formed on the substrate can be smoothed, and variations in functionality such as conductivity and insulation can be suppressed.

[4 Ink] The ink of the present invention is preferably such that the ratio η2/η1 between the viscosity η1 of the ink at the temperature when it is ejected and the viscosity η2 at the temperature when it is hit is 100 or more. By setting η2/η1 to 100 or more, it is possible to suppress the occurrence of bulge and form a high-precision pattern. Furthermore, by setting η2/η1 to 200 or more, or further to 500 or more, it is possible to form a high-precision pattern even on a substrate with different types of components or with uneven surfaces.

Furthermore, in the present invention, it is more desirable to use one type of ink, such as a hot melt type, a gel type, or a thixotropy type, as described below.

<Viscosity> The viscosity of the ink when ejecting and when hitting is not particularly limited as long as it is within the range that satisfies the above ratio, but for example, the viscosity (η1) when the temperature when ejecting is set to 75°C is preferably within the range of 3 to 15 mPa·s from the perspective of the ejection performance of the inkjet head. On the other hand, the viscosity (η2) when the temperature when hitting is set to room temperature (25°C) is preferably within the range of 1×10 ² to 1×10 ⁴ mPa·s from the perspective of fixing the ink on the substrate when hitting and suppressing the occurrence of bulging, etc.

The so-called "viscosity η2 at the temperature at the time of impact" may refer to the viscosity of the ink reached before "the flow of the ink caused by the wetting and expansion of the ink on the substrate (not caused by the impact at the time of impact)" is substantially triggered. Specifically, it is the viscosity reached within 1 second from the time when the ink hits the substrate. However, in the present invention, it is set to the temperature of the substrate when the ink hits. On the other hand, regarding the "viscosity η1 at the temperature at the time of ejection", it is set to the temperature of the nozzle at the time when the ink is ejected from the nozzle.

The viscosity measurement is performed by placing the aforementioned ink in a stress-controlled rheometer capable of temperature control (e.g., Physica MCR300, manufactured by Anton Paar), heating it to 100°C, and then cooling it to 25°C at a cooling rate of 0.1°C/s, and then measuring the viscosity. The measurement can be performed using a cone with a diameter of 75.033 mm and a cone angle of 1.017° (e.g., CP75-1, manufactured by Anton Paar). In addition, temperature control is performed using a temperature control device, for example, a Peltier element type temperature control device (TEK150P/MC1) attached to Physica MCR300.

<Control method of viscosity ratio η2/η1> The viscosity ratio η2/η1 of the ink of the present invention can be appropriately satisfied by, for example, setting the physical conditions such as the composition of the ink, the temperature and humidity when the ink hits, etc. As the ink of the present invention, it is ideal to have a performance that changes the viscosity by a phase change mechanism such as hot melting, thixotropy, or gelation. By having the above-mentioned performance, the phase change function of the ink is exerted during the period from the time of ink ejection to the time of hitting, so that the viscosity ratio η2/η1 of the present invention can be satisfied.

In the present invention, "hot melt" means that the ink melts by applying heat, and "phase change mechanism caused by hot melt" means a mechanism that changes from a "low viscosity state (when ejecting)" by being heated (melted) to a "high viscosity state (when hitting)" by being cooled. From the perspective of making the phase change mechanism caused by hot melt work properly, it is more ideal to change the temperature of the ink when ejecting and when hitting. For example, a method of heating the ink when ejecting and cooling the ink when hitting can be listed, and it is ideal to perform one or both of these.

In the present invention, when the temperature of the ink changes during ejection and impact, it is ideal to use general temperature adjustment means such as a heater (heating means) for heating the ink filled into the inkjet head or a cooling means for cooling the substrate.

In the present invention, the so-called "tactile change" refers to a property between "plastic solid like gel" and "non-Newtonian liquid like sol", and refers to a property whose viscosity changes over time. In addition, the so-called "phase change mechanism caused by tactile change" refers to a phase change mechanism that changes from "a state of low viscosity under the action of shear stress caused by stirring or vibration (when discharging)" to "a state of high viscosity (after hitting)" by reducing the action of shear stress or by being stationary. For example, a shear stress imparting means of applying agitation or vibration (micro-vibration) to the ink filled in the inkjet head can be appropriately used to exert the phase change mechanism caused by thixotropy.

In the present invention, the so-called "phase transition mechanism due to gelation" refers to a phase transition mechanism in which the solute loses its independent mobility and forms a structure that aggregates, and changes from "a state of low viscosity (when ejected) due to the independent mobility of the solute" to "a state of high viscosity (when hit)" through the interaction of "polymer grids and aggregate structures of microparticles formed by chemical or physical aggregation". In this case, it is ideal that the ink contains a general gelling agent such as an oil gelling agent (details will be described later).

From the viewpoint of making the phase change mechanism due to gelation work properly, it is more ideal to change the temperature of the ink when ejecting and when hitting. For example, it is ideal to heat the ink to a temperature above the gel-sol phase change temperature (gelation temperature) when ejecting to make it sol-cured in advance, and to cool the ink to a temperature below the gel-sol phase change temperature (gelation temperature) when hitting to make it gel-cured.

[4.1 Thermosetting inkjet ink] The ink used in the present invention is preferably a thermosetting inkjet ink that "contains a compound having a thermosetting functional group and a gelling agent, and undergoes a sol-gel phase transition caused by temperature." Furthermore, the thermosetting inkjet ink is more preferably a compound having a photopolymerizable functional group and a photopolymerization initiator.

<Thermosetting functional group> Examples of thermosetting functional groups include hydroxyl group, carboxyl group, isocyanate group, epoxy group, (meth)acrylic group, maleimide group, butyl group, alkoxy group, etc. These may be used alone or in combination of two or more.

<Gelling agent> Ideally, the gelling agent is maintained in a uniformly dispersed state in the cured film cured by light and heat, thereby preventing water from penetrating into the cured film.

As the gelling agent, it is preferable to include at least one compound represented by the following general formula (G1) or (G2). In this way, the gelling agent can be uniformly dispersed in the cured film without hindering the curability of the ink. In addition, in inkjet printing, the pinning property is good, and it is possible to draw a thin line and a film thickness at the same time, and the reproducibility of the thin line is excellent. General formula (G1): R ₁ -CO-R ₂ General formula (G2): R ₃ -COO-R ₄ [In the formula, R ₁ to R ₄ each independently represent a straight chain part having more than 12 carbon atoms and may also have a branched alkyl chain].

Ketone wax represented by general formula (G1) or ester wax represented by general formula (G2) has a linear or branched alkyl group (alkyl chain) with a carbon number of 12 or more, so the crystallinity of the gelling agent is further improved, the water resistance is improved, and sufficient space is generated in the card house structure described below. Therefore, the ink medium such as the solvent and the photopolymerizable compound is easily contained in the above space, and the pinning property of the ink becomes higher.

Furthermore, the carbon number of the linear or branched alkyl group (alkyl chain) is ideally 26 or less. If it is 26 or less, the melting point of the gelling agent will not be too high, and therefore, there is no need to overheat the ink when ejecting it.

Based on the above viewpoints, _R1 and _R2 , or _R3 and _R4 , are particularly preferably linear hydrocarbon groups having 12 to 23 carbon atoms. Furthermore, from the viewpoint of increasing the gelling temperature of the ink and gelling the ink more rapidly after the impact, it is preferred that either _R1 or _R2 , or either _R3 or _R4 , is a saturated hydrocarbon group having 12 to 23 carbon atoms.

Based on the above viewpoints, it is more preferable that both _R1 and _R2 or both _R3 and _R4 are saturated alkyl groups having 11 to 23 carbon atoms.

The content of the gelling agent is preferably in the range of 0.5 to 5.0 mass % relative to the total mass of the ink. By setting the content of the gelling agent in the above range, the solubility of the gelling agent in the solvent component and the nailing effect are improved, and further, the water resistance when it is used as a cured film is improved. In addition, 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 mass %.

Furthermore, based on the following viewpoints, the gelling agent is preferably crystallized in the ink at a temperature below the gelling temperature of the ink. The so-called gelling temperature refers to the temperature at which "when the ink that has been solvated or liquefied due to heating is cooled, the gelling agent changes phase from sol to gel and causes the viscosity of the ink to change rapidly." Specifically, the temperature at which the viscosity of the solvated or liquefied ink can be measured while being cooled by a viscoelasticity measuring device (e.g., MCR300, manufactured by Physica) and the viscosity rises rapidly is set as the gelling temperature of the ink.

<Compounds with photopolymerizable functional groups> Compounds with photopolymerizable functional groups (also called photopolymerizable compounds) are compounds that react and polymerize or crosslink due to irradiation with active light and have the function of hardening the ink. Examples of photopolymerizable compounds include free radical polymerizable compounds and cationic polymerizable compounds. Photopolymerizable compounds can be any of monomers, polymerizable oligomers, prepolymers, or mixtures thereof. Photopolymerizable compounds can contain only one type or two or more types in the inkjet ink.

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

The cationically polymerizable compound may be an epoxy compound, a vinyl ether compound, an oxetane compound, etc. The inkjet ink may contain only one cationically polymerizable compound or two or more cationically polymerizable compounds.

<Photopolymerization initiator> The photopolymerization initiator is preferably a photo-free radical initiator when the photopolymerizable compound is a free radical polymerizable compound, and a photoacid generator when the photopolymerizable compound is a cationic polymerizable compound.

The ink of the present invention may contain only one photopolymerization initiator or two or more photopolymerization initiators. The photopolymerization initiator may be a combination of a photoradical initiator and a photoacid generator. The photoradical initiator includes a cleavage-type free radical initiator and a hydrogen-abstracting free radical initiator.

<Colorant> The ink used in the present invention may further include a colorant as needed. The colorant may be a dye or a pigment, but from the perspective of having good dispersibility relative to the components of the ink and excellent weather resistance, a pigment is ideal.

The ideal dispersion of pigments is to make the volume average particle size of pigment particles ideally within the range of 0.08-0.5μm, the maximum particle size ideally within the range of 0.3-10μm, and more ideally within the range of 0.3-3μm. The dispersion of pigments is adjusted by the selection of pigments, dispersants and dispersion media, dispersion conditions, and filtering conditions.

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

The ink used in the present invention may further contain a dispersion medium for dispersing the pigment as required. Although a solvent may be contained in the ink as a dispersion medium, in order to suppress the residual solvent in the formed printed matter, it is more ideal to use the above-mentioned general photopolymerizable compound (especially a monomer with low viscosity) as a dispersion medium.

When dyes are used, oil-soluble dyes and the like can be cited.

The colorant may be contained in the ink in one or more forms and the color may be adjusted to a desired color. The content of the colorant is preferably in the range of 0.1 to 20% by mass, more preferably in the range of 0.4 to 10% by mass, relative to the total amount of the ink.

<Other components> The ink used in the present invention may further contain other components such as polymerization inhibitors, surfactants, curing accelerators, coupling agents, ion scavengers, etc. within the scope of being able to obtain the effects of the present invention. These components may be contained in the ink in one or more types. In addition, from the perspective of curability, although it is originally ideal to have no solvent, a solvent may be added to adjust the viscosity of the ink.

<Physical properties> The ink used in the present invention preferably has a phase transition point in the range of 40°C or more and less than 100°C. If the phase transition point is above 40°C, the ink will gel quickly after hitting the printing medium, so the nailing property will become higher. In addition, if the phase transition point is less than 100°C, the ink will be easy to handle and the ejection stability will be higher. From the perspective of being able to eject the ink at a lower temperature and reduce the burden on the image forming device, the phase transition point of the ink is more ideally in the range of 40 to 60°C.

From the perspective of further improving the ejection performance of ink from the inkjet head, the average dispersed particle size of the pigment particles of the present invention is preferably in the range of 50 to 150 nm, and more preferably in the range of 80 to 130 nm. Moreover, the maximum particle size is preferably in the range of 300 to 1000 nm. In addition, in the present invention, the "average dispersed particle size" of the pigment particles refers to the value obtained by the dynamic light scattering method using ZETASIZER NANO ZSP (manufactured by Malvern). For ink containing colorants, since its concentration is high, light does not pass through the measuring machine, so the ink is diluted 200 times and measured. The measuring temperature is set to room temperature (25°C).

[5 Method for forming solder resist pattern] The ink used in the present invention is preferably a solder resist ink for forming a solder resist pattern used in a printed circuit board. By using the ink to form a solder resist pattern, it is possible to prevent moisture from penetrating into the solder resist pattern, and as a result, the adhesion between the copper foil and the solder resist pattern interface at the printed circuit board is improved. In addition, it is possible to prevent copper migration and suppress the reduction of insulation.

The method for forming a solder resist pattern using the ink used in the present invention preferably includes the following steps (1) of ejecting the ink from the nozzle of the inkjet head and causing it to hit the printed circuit board on which the circuit is formed, and the following step (3) of heating the ink and performing formal hardening. When the ink used in the present invention contains a compound having a photopolymerizable functional group and a photopolymerization initiator, it is preferably included between the above steps (1) and (3) to irradiate the hit ink with active light and temporarily harden the ink (step (2)).

Process (1): In process (1), the ink droplets of the present invention are ejected from the inkjet head and are made to hit the positions corresponding to the solder resist pattern to be formed on the printed circuit board as the printing medium to perform patterning. The ejection method from the inkjet head can be either on-demand or continuous.

By ejecting the ink droplets from the inkjet head in a heated state, the ejection stability can be improved. The temperature of the ink during ejection is preferably in the range of 40 to 100°C, and in order to further improve the ejection stability, it is more preferably in the range of 40 to 90°C. In particular, it is ideal to eject the ink at a general ink temperature that "makes the viscosity of the ink in the range of 7 to 15 mPa·s, and more preferably in the range of 8 to 13 mPa·s".

In order to improve the ejection performance of the sol-gel phase change ink from the inkjet head, the temperature of the ink when it is filled into the inkjet head is ideally set to (gelation temperature + 10) ℃ ~ (gelation temperature + 30) ℃ of the ink. If the temperature of the ink in the inkjet head is less than (gelation temperature + 10) ℃, the ink will gel inside the inkjet head or on the nozzle surface, and the ejection performance of the ink will be easily reduced. On the other hand, if the temperature of the ink in the inkjet head exceeds (gelation temperature + 30) ℃, the ink will become too hot, so there is a situation where the ink components deteriorate.

The method of heating the ink is not particularly limited. For example, at least one of the ink supply system, such as the ink tank constituting the head carriage, the supply pipe, the ink tank in the front chamber close to the front of the nozzle, the pipe with a filter, and the piezoelectric nozzle, can be heated by a flat heater, a belt heater, or warm water. The amount of ink droplets when ejected is preferably within the range of 2 to 20 pL based on the viewpoint of printing speed and image quality.

The printed circuit substrate is not particularly limited, but ideally, for example, it can be a copper-clad laminate of all grades (FR-4, etc.) among materials such as paper phenol, paper epoxy, glass cloth epoxy, glass polyimide, glass cloth/non-woven epoxy, glass cloth/paper epoxy, synthetic fiber epoxy, fluorine-polyethylene-PPO-cyanate, etc., or other polyimide films, PET films, glass substrates, ceramic substrates, wafer boards, stainless steel plates, etc.

Process (2): In process (2), the ink hit in process (1) is irradiated with active light to temporarily harden the ink. Active light can be selected from electron beams, ultraviolet rays, α rays, γ rays, and X-rays, but ultraviolet rays are more ideal. Ultraviolet irradiation can be performed at a wavelength of 395nm using, for example, a water-cooled LED manufactured by Phoseon Technology. By using LED as a light source, poor hardening of the ink caused by melting of the ink due to the radiation heat of the light source can be suppressed.

The ultraviolet ray irradiation is performed in such a manner that the peak illuminance of the ultraviolet ray having a wavelength in the range of 370 to 410 nm on the surface of the solder resist pattern is preferably in the range of 0.5 to 10 W/cm ² , more preferably in the range of 1 to 5 W/cm ^2. From the viewpoint of suppressing the radiation heat from being irradiated to the ink, the amount of light irradiated to the solder resist pattern is preferably less than 500 mJ/cm ^2. The active light irradiation is preferably performed between 0.001 and 300 seconds after the ink hits, and in order to form a high-precision solder resist pattern, it is more preferably performed between 0.001 and 60 seconds.

Process (3): In process (3), after the temporary hardening in (2), the ink is further heated to make it harden. The ideal heating method is, for example, to place the ink in an oven set at 110 to 180°C for 10 to 60 minutes.

In addition, the ink used in the present invention can be used as an adhesive or sealant for electronic parts, a circuit protective agent, etc., in addition to being used as the ink for forming the aforementioned solder resist pattern.

In the present invention, the location where the solder resist pattern is provided is not particularly limited, but, as described above, when it is formed across different component lands or across a component land having projections and depressions, the effect of the present invention becomes particularly significant.

≪Inkjet printing device≫ The following describes the functions of the basic components of the inkjet printing device (also referred to as "inkjet printer device" or "inkjet recording device") that can be used in the multiple-mode of the present invention.

The figure shown in FIG8 is a schematic diagram showing an inkjet printing device 1 by a multiple-step method, A is a front view, and B is a top view. This inkjet printing device 1 is basically a printing device that ejects ink by making the nozzle 3 reciprocate to perform overlapping printing multiple times, and has: a bracket 2 on which the nozzle is mounted, an X-direction linear platform 4 for moving the bracket 2, a table 5 on which a substrate is installed, and a Y-direction linear platform 6 for moving the table 5, etc.

The inkjet printing device 1 performs printing by moving the nozzle 3 in the X direction and the table 5 on which the substrate is placed in the Y direction. Also, although not shown in the figure, the inkjet printing device 1 has a device for controlling the ejection of ink from the nozzle 3 and a computer for controlling the XY platform. The computer for controlling the XY platform controls the movement of the XY platform based on the image data. In addition, the above-mentioned computer has a CPU (Central Processing Unit), ROM (Read Only Memory), and RAM (Random Access Memory), etc.

As a printing method in the X direction, a bracket 2 with a nozzle 3 mounted thereon is mounted on a linear platform 4 in the X direction, and is moved to a desired position by a computer that controls the XY platform, thereby printing is performed. In addition, as a printing method in the Y direction, a table 5 with a substrate is moved in the Y direction, and printing is performed by ejecting ink from the nozzle when the substrate passes under the nozzle. The encoder disposed at the linear platform 6 in the Y direction and the device that controls the ejection of ink from the nozzle 3 are linked to each other, and the ink is ejected at the resolution of the image data in response to the encoder signal.

When printing with a higher resolution than the resolution of the print head in the X direction, the print head is moved multiple times in the X direction to print. For example, when printing at 2400dpi with a single inkjet head with a resolution of 600dpi, after the print head performs the first scan in the Y direction, it is moved 10.6μm (equivalent to 1 pixel of 2400dpi) in the X direction and the second scan is printed in the Y direction. Furthermore, the print head is moved 10.6μm in the X direction and the third scan is printed in the Y direction. After that, it is moved 10.6μm in the X direction and the fourth scan is printed in the Y direction to complete the printing.

In the above description, although the printing is performed with the conveying direction set to only one direction, there is also a case where printing is performed in a reciprocating manner (also called "bidirectional printing"). In addition, when the printing area is larger than the width of the printhead, printing is performed by moving the printhead in the X direction by the width of the printhead.

Furthermore, the main scanning direction and the auxiliary scanning direction of the ink ejection device may not be perpendicular or parallel to the nozzle array. The ink ejection device and the substrate serving as the printing medium are unlikely to produce streaks or unevenness regardless of whether only one of them is moved to form a pattern or both are moved to form a pattern.

The following is a description of a multiple-mode inkjet printing device other than the above that can be used in the present invention. The ink ejection device (synonymous with the above-mentioned "nozzle") has a plurality of nozzle holes for ejecting ink. The nozzle holes are preferably arranged in a row, but the nozzle row and the main scanning direction (synonymous with the above-mentioned "Y direction") and the secondary scanning direction (synonymous with the above-mentioned "X direction") of the nozzle may not be perpendicular or parallel, and are not particularly limited.

FIG. 41 shows a printing method when the direction of the nozzle array is not perpendicular or parallel to either the X direction or the Y direction but is tilted. Even an inkjet printing device with a tilted nozzle array can be used in the pattern forming method of the present invention.

FIG. 42 shows a printing method when the direction of the ink ejection device itself is not perpendicular or parallel to either the X direction or the Y direction but is tilted. By appropriately changing the angle between the ink ejection device and the main scanning direction, the interval between the dots formed can be changed, so the nozzle resolution can be improved without adding an ink ejection device. Even such an inkjet printing device can be used in the pattern forming method of the present invention.

Furthermore, in the above-mentioned inkjet printing device 1, although printing is performed by moving the nozzle in the X direction and the substrate in the Y direction, an inkjet printing device that moves the nozzle in the Y direction and the substrate in the X direction, an inkjet printing device that moves the substrate in either the X direction or the Y direction, or an inkjet printing device that moves the nozzle in either the X direction or the Y direction can also be used in the pattern forming method of the present invention.

FIG. 34 shows a method of printing by the inkjet printing device 1. In the first scan, the nozzle is fixed, and when the substrate moves in the direction of the arrow and passes under the nozzle, the nozzle ejects droplets of ink. Thus, in the positional relationship between the substrate and the nozzle, the nozzle moves relatively in the main scanning direction. When printing is performed at a higher resolution than the resolution of the nozzle, in the second scan, the nozzle moves in the direction of the arrow, and the substrate is moved in the direction of the arrow again to eject droplets of ink. This action is repeated to complete printing.

In the inkjet printing device 100 shown in FIG. 33, the bracket 2 on which the nozzle 3 is mounted is mounted on the linear platform 6 in the Y direction, and is moved to the desired position by a computer that controls the XY platform, thereby performing printing. 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 mounted is moved in the X direction, and the next printing in the main scanning direction in the Y direction is performed. Similar to the inkjet printing device 1, the encoder disposed at the linear platform 4 in the X direction and the device for controlling the ejection of ink from the nozzle 3 are linked to each other, and the ink is ejected at the resolution of the image data in response to the encoder signal.

FIG. 35 shows a method of printing by using an inkjet printing device 100. In the first scan, the nozzle is moved in the main scanning direction on a fixed substrate and ink droplets are ejected. Then, in the second scan, the nozzle moves relatively in the sub-scanning direction in the positional relationship between the substrate and the nozzle by moving the substrate in the direction of the arrow. After that, the ink ejection device is moved in the main scanning direction on the fixed substrate again and ink droplets are ejected. This action is repeated to complete printing.

FIG. 36 shows a method of printing by using an inkjet printing device that moves a substrate in both the X and Y directions. In the first scan, the nozzle is fixed, and when the substrate is moved in the direction of the arrow and passes under the nozzle, droplets of ink are ejected from the nozzle, whereby the nozzle moves relatively in the main scanning direction in the positional relationship between the substrate and the nozzle. Next, in the second scan, by moving the substrate in the direction of the arrow, the nozzle moves relatively in the sub-scanning direction in the positional relationship between the substrate and the nozzle. Thereafter, the ink ejection device is moved in the main scanning direction again on the fixed substrate to eject droplets of ink. This action is repeated to complete printing.

FIG. 37 shows a method of printing by moving the inkjet printing device in both the X and Y directions. In the first scan, the inkjet printing device moves in the main scanning direction on a fixed substrate and ejects ink droplets. Then, in the second scan, the inkjet printing device moves in the direction of the arrow and again moves the substrate in the direction of the arrow to eject ink droplets. This operation is repeated to complete printing.

Furthermore, by arranging a plurality of print heads side by side and mounting them on a bracket, the number of scans can be reduced and the printing time can be shortened.

FIG. 40 shows a method of performing split printing of a 2400 dpi resolution using four inkjet heads with a nozzle resolution of 600 dpi. The four inkjet heads are mounted on a carriage with an offset in a pitch that results in a 2400 dpi resolution.

As shown in FIG. 30A and FIG. 30B, when printing with a resolution of 2400 dpi using four divided image data using one inkjet head with a nozzle resolution of 600 dpi, 16 scans are required. However, as shown in FIG. 40, when four inkjet heads are installed with a certain offset, the first to fourth scans in FIG. 30A can be performed by one scan, so printing can be completed by a total of four scans, and the printing time can be shortened.

In the present invention, as described above, a multi-level grayscale image can also be used to control the amount of liquid in correspondence with the level or concentration of each pixel. For example, when a pattern is formed on a substrate with concave and convex parts, by increasing the amount of liquid droplets that hit the concave part or the periphery of the concave part, the pattern formed on the substrate can be smoothed, and the functional variation of conductivity or insulation can be suppressed.

For example, by applying noise filtering to a 256-level 30% grayscale image using Adobe's Photoshop, it is possible to create random multi-level grayscale image data as shown in Figure 16. Based on this image data, the amount of ink is distributed in a manner such as "the black portion of the 0-86 level is 7pL, the gray portion of the 87-172 level is 3.5pL, and the white portion of the 173-255 level is 0pL."

The formation of dots with different liquid amounts corresponding to each pixel can be achieved by changing the ejection waveform when the ink is ejected from the nozzle or by forming a plurality of dots for the same pixel.

For example, in the case of the above-mentioned liquid volume distribution, by using an inkjet head with a liquid volume of 3.5 pL and stipulating "2 drops are ejected in the black part of the 0-86 level, 1 drop is ejected in the gray part of the 87-172 level, and no ejection is performed in the white part of the 173-255 level", it is possible to form dots caused by different liquid volumes.

As a method of printing in a random multiple manner in the present invention, there are "a method of dividing a source image into a random multiple number of non-overlapping images and printing them" or "a method of setting a hit to be random using a function similar to a random number through an inkjet ejection control system" and the like.

The segmented image data can be produced by the following method. It can be produced by image processing software such as Adobe's image processing software Photoshop 2020. For example, a grayscale image is converted into black and white in two levels using Photoshop by error diffusion method, and a random image of white and black is produced. Then, the image is inverted in color to produce an image in which white and black are inverted. [Example]

The following examples are given to specifically illustrate the present invention, but the present invention is not limited to these examples. In addition, although "parts" or "%" are used in the examples, they represent "parts by mass" or "% by mass" unless otherwise specified. In addition, in the following examples, the operation is performed at room temperature (25°C) unless otherwise specified.

≪Example 1≫ [Preparation of ink 1] ＜Preparation of pigment dispersion liquid＞ The dispersant and dispersion medium shown below are placed in a stainless steel beaker, and heated on a hot plate at 65°C for 1 hour while stirring to dissolve, and then cooled to room temperature. Then, the pigment is added, and 200g of zirconium beads with a diameter of 0.5mm are placed in a glass bottle and sealed. This is dispersed by a paint shaker until it becomes the desired particle size, and then the zirconium beads are removed.

(Yellow pigment dispersion) Dispersant 1: EFKA7701 (manufactured by BASF) 5.6 parts by mass Dispersant 2: Solsperse22000 (manufactured by Lubrizol Japan) 4 parts by mass Dispersant: Dipropylene glycol diacrylate (containing 0.2% UV-10) 80.6 parts by mass Pigment: PY185 (manufactured by BASF, Paliotol Yellow D1155) 13.4 parts by mass

(Cyan pigment dispersion) Dispersant: EFKA7701 (manufactured by BASF) 7.0 parts by mass Dispersant: Dipropylene glycol diacrylate (containing 0.2% UV-10) 70.0 parts by mass Pigment: PB15:4 (manufactured by Dainichi Seika, Chromofine Blue 6332JC) 23.0 parts by mass

The prepared dispersions were mixed in the following ratios and filtered with a TEFLON (registered trademark) 3μm filter membrane manufactured by ADVATEC to prepare ink 1. The viscosity (η1) at 75°C when the ink was ejected was 8.5 mPa·s, and the viscosity (η2) at room temperature (25°C) which was the temperature when the ink hit was 9.2 mPa·s.

Yellow pigment dispersion                                         3.0 parts by mass Cyan pigment dispersion                                           1.0 parts by mass Epoxy ester (M-600A: manufactured by Kyoyoung Chemical Co., Ltd.)                  30.0 parts by mass Trixene BI7961 (manufactured by LANXESS)                 10.0 parts by mass Urethane acrylate (AH-600: manufactured by Kyoyoung Chemical Co., Ltd.) 10.0 parts by mass M222 (manufactured by Miwon Co., Ltd.)                                 27.7 parts by mass EM2382 (manufactured by Changxing Chemical Co., Ltd.)                             10.0 parts by mass Photoinitiator: diphenyl (2,4,6-trimethylbenzyl) phosphine oxide (TPO) 3.0 parts by mass Photoinitiator: 2-isopropylthioxanthine (ITX)              3.0 parts by mass

[Printing of patterns] A linear XY stage and control system (IJCS-1: manufactured by Konica Minolta) equipped with an inkjet head (KM1800iSHC-C: manufactured by Konica Minolta, resolution 600 dpi) was used to print a pattern on an optical PET film serving as a substrate under the following conditions, and the pattern was exposed and cured using a UV-LED light source with a wavelength of 395 nm at an irradiation energy of 500 mJ/ ^cm2 to produce a printed material 1.

[Division printing (number of image divisions 2)] As shown in FIG. 28, the image data is divided into division image data No. 1 and No. 2 in such a way that "in the image data of the pattern portion other than the boundary portion, each pixel does not overlap when printed in an overlapping manner, and is not divided in accordance with the order of rows and columns in which each pixel is arranged and does not have a certain periodicity, and in the image data of the boundary portion, it corresponds to the block method". After that, each of the division image data is sequentially overlapped and printed under the following conditions.

Printing pattern: In a 70mm×70mm square, place a 3mm×2mm blank square parallel to the main scanning direction and the sub-scanning direction Number of image divisions: 2 Division image data: Figure 28, refer to the division image data Resolution: 2400dpi×2400dpi (transport direction) Number of passes: 8 times (600dpi×8) Printing direction (main scanning direction): single-direction printing Printing direction (sub-scanning direction): positive direction printing Movement distance of the nozzle row direction between each pass: 10.6μm Printing method of the pattern part except the border part: random multiple times method, refer to Figure 28 Border part printing method: block method, refer to Figure 18 Number of dots in the border width: 1 Printing sequence: Pattern formation method B Liquid distribution: 3.5pL across the board Nozzle temperature (temperature when ink is ejected): room temperature (25°C) Substrate temperature (temperature when ink hits): room temperature (25°C)

≪Example 2≫ Example 2 printed material 2 was produced in the same manner as Example 1 except that ink 1 was changed to ink 2 and the nozzle temperature (when the ink was ejected) was changed to 75°C.

[Preparation of Ink 2] The dispersion prepared in Ink 1 was mixed in the following ratio and filtered with a TEFLON (registered trademark) 3μm filter membrane manufactured by ADVATEC to prepare ink. The viscosity (η1) at 75°C when the ink was ejected was 10mPa･s, and the viscosity (η2) at room temperature (25°C) when the ink was hit was 1×10 ⁴ mPa･s. That is, the viscosity ratio η2/η1 was 1000.

Yellow pigment dispersion                                         3.0 parts by mass Cyan pigment dispersion                                       1.0 parts by mass Distearyl ketone                        1.1 parts by mass Behenyl behenate   1.2 parts by mass Epoxy ester (M-600A: manufactured by Kyoyoung Chemical)                 30.0 parts by mass Trixene BI7961 (manufactured by LANXESS)                 10.0 parts by mass Urethane acrylate (AH-600: manufactured by Kyoyoung Chemical) 10.0 parts by mass M222 (manufactured by Miwon)                                 27.7 parts by mass EM2382 (produced by Changxing Chemical Co., Ltd.)                             10.0 parts by mass Photoinitiator: diphenyl (2,4,6-trimethylbenzyl) phosphine oxide (TPO) 3.0 parts by mass Photoinitiator aid: 2-isopropylthioxanone (ITX)              3.0 parts by mass

≪Example 3≫ Printed material 3 was produced in the same manner as Example 2 except that the printing conditions were changed to the following conditions.

[Division printing (number of image divisions 2)] As shown in FIG. 44, the image data is divided into division image data No. 1 and No. 2 in such a way that "in the image data of the pattern portion other than the border portion, each pixel does not overlap when printed in an overlapping manner, and is not divided in accordance with the order of rows and columns in which each pixel is arranged and does not have a certain periodicity, and in the image data of the border portion, it corresponds to the interweaving method". After that, each of the division image data is sequentially overlapped and printed under the following conditions.

Printing pattern: In a 70mm×70mm square, a 3mm×2mm blank square parallel to the main scanning direction and the sub-scanning direction is arranged Number of image divisions: 2 Image division data: Figure 44, refer to the image division data Resolution: 2400dpi×2400dpi (transport direction) Number of passes: 8 times (600dpi×8) Printing direction (main scanning direction): single-direction printing Printing direction (sub-scanning direction): positive direction printing Movement distance of the nozzle row direction between each pass: 10.6μm Printing method of the pattern part except the border part: random multiple times, refer to Figure 44 Border part printing method: interweaving method, refer to Figure 21 Number of dots in the border width: 1 Printing sequence: Pattern formation method D Liquid distribution: 3.5pL across the board Nozzle temperature (temperature when ink is ejected): 75℃ Substrate temperature (temperature when ink hits): Room temperature (25℃)

≪Example 4≫ Printed material 4 was produced in the same manner as Example 2 except that the printing conditions were changed to the following conditions.

[Division printing (number of image divisions 2)] For the image data, as shown in FIG. 45, "in the image data of the pattern portion other than the border portion, the pixels are not overlapped when printed in an overlapping manner, and the image data is divided by the image processing software in a manner that is not in accordance with the order of rows and columns in which the pixels are arranged and does not have a certain periodicity, and the image data of the border portion corresponds to the interweaving method." The division image data No. 1 and No. 2 are produced. After that, each of the division image data is sequentially overlapped and printed under the following conditions.

Printing pattern: In a 70mm×70mm square, place a 2mm×2mm blank square parallel to the main scanning direction and the sub-scanning direction Number of image divisions: 2 Division image data: Figure 45, refer to the division image data Resolution: 2400dpi×2400dpi (transport direction) Number of passes: 8 times (600dpi×8) Printing direction (main scanning direction): single-direction printing Printing direction (sub-scanning direction): positive direction printing Movement distance of the nozzle row direction between each pass: 10.6μm Printing method of the pattern part except the border part: random multiple times method, refer to Figure 45 Border part printing method: interweaving method, refer to Figure 22 Number of dots in the border width: 1 Printing sequence: Pattern formation method D Liquid distribution: 3.5pL across the board Nozzle temperature (temperature when ink is ejected): 75℃ Substrate temperature (temperature when ink hits): Room temperature (25℃)

≪Example 5≫ Printed material 5 was produced in the same manner as Example 2 except that the printing conditions were changed to the following conditions.

[Division printing (number of image divisions 2)] As shown in FIG. 43, the image data is divided into division image data No. 1 and No. 2 in such a way that "in the image data of the pattern part other than the border part, each pixel does not overlap when printed in an overlapping manner, and is not divided in accordance with the order of rows and columns in which each pixel is arranged and does not have a certain periodicity, and in the image data of the border part, it corresponds to the block method". After that, each of the division image data is sequentially overlapped and printed under the following conditions.

Printing pattern: In a 70mm×70mm square, a 3mm×2mm blank square parallel to the main scanning direction and the sub-scanning direction is arranged Number of image divisions: 2 Image division data: Figure 43, refer to the image division data Resolution: 2400dpi×2400dpi (transport direction) Number of passes: 8 times (600dpi×8) Printing direction (main scanning direction): single-direction printing Printing direction (sub-scanning direction): positive direction printing Movement distance of the nozzle row direction between each pass: 10.6μm Printing method of the pattern part except the border part: random multiple times method, refer to Figure 43 Border part printing method: block method, refer to Figure 18 Number of dots in the border width: 1 Printing sequence: Pattern formation method C Liquid distribution: 3.5pL across the board Nozzle temperature (temperature when ink is ejected): 75℃ Substrate temperature (temperature when ink hits): Room temperature (25℃)

≪Example 6≫ Printed material 6 was produced in the same manner as Example 2 except that the printing conditions were changed to the following conditions.

[Division printing (number of image divisions 3)] Image data is divided into boundary parts and pattern parts other than the boundary parts as shown in FIG. 27A and FIG. 27B. In addition, "in the image data of the pattern part other than the boundary part, each pixel does not overlap when printed in an overlapping manner, and is not divided by the image processing software in a manner that is not in accordance with the order of rows and columns in which each pixel is arranged and does not have a certain periodicity, and in the image data of the boundary part, it corresponds to the block method" to produce the division image data No. 1 to No. 3. After that, each of the division image data is printed in sequence in an overlapping manner under the following conditions.

Printing pattern: In a 70mm×70mm square, a 3mm×2mm blank square parallel to the main scanning direction and the sub-scanning direction is arranged Number of image divisions: 3 Image division data: Figure 27A and Figure 27B, refer to the image division data Resolution: 2400dpi×2400dpi (transport direction) Number of passes: 12 times (600dpi×8) Printing direction (main scanning direction): single direction printing Printing direction (sub-scanning direction): positive direction printing Movement distance of the nozzle row direction between each pass: 10.6μm Printing method of the pattern part except the border part: random multiple times method, refer to Figure 27 Border part printing method: block method, refer to Figure 18 Number of dots in the border width: 1 Printing order: Pattern formation method A Liquid distribution: 3.5pL on the entire surface Nozzle temperature (temperature when ink is ejected): 75℃ Substrate temperature (temperature when ink hits): Room temperature (25℃)

≪Example 7≫ Printed material 7 was produced in the same manner as Example 2 except that the printing conditions were changed to the following conditions.

[Division printing (number of image divisions 2)] As shown in FIG. 47, the image data is divided into division image data No. 1 and No. 2 in such a way that "in the image data of the pattern portion other than the boundary portion, each pixel does not overlap when printed in an overlapping manner, and is not divided in accordance with the order of rows and columns in which each pixel is arranged and does not have a certain periodicity, and in the image data of the boundary portion, it corresponds to the block method". After that, each of the division image data is sequentially overlapped and printed under the following conditions.

Printing pattern: In a 70mm×70mm square, a 2mm×2mm blank square (diamond) is arranged that is not parallel to the main scanning direction and the sub-scanning direction Number of image divisions: 2 Division image data: Figure 47, refer to the division image data Resolution: 2400dpi×2400dpi (transport direction) Number of passes: 8 times (600dpi×8) Printing direction (main scanning direction): single-direction printing Printing direction (sub-scanning direction): positive direction printing Movement distance of the nozzle row direction between each pass: 10.6μm Printing method of the pattern part except the border part: random multiple times method, refer to Figure 47 Border part printing method: block method, refer to Figure 24 Number of dots in the border width: 1 Printing order: Pattern formation method B Liquid distribution: 3.5pL on the entire surface Nozzle temperature (temperature when ink is ejected): 75℃ Substrate temperature (temperature when ink hits): Room temperature (25℃)

≪Example 8≫ Printed material 8 was produced in the same manner as Example 2 except that the printing conditions were changed to the following conditions.

[Division printing (number of image divisions 2)] For the image data, as shown in FIG. 48, "in the image data of the pattern portion other than the border portion, the pixels are not overlapped when printed in an overlapping manner, and the image data is divided by the image processing software in a manner that is not in accordance with the order of rows and columns in which the pixels are arranged and does not have a certain periodicity, and the image data of the border portion corresponds to the block method." The division image data No. 1 and No. 2 are produced. After that, each of the division image data is sequentially overlapped and printed under the following conditions. However, the width dots at the border portion are set to 2 dots.

Printing pattern: In a 70mm×70mm square, place a 3mm×2mm blank square parallel to the main scanning direction and the sub-scanning direction Number of image divisions: 2 Division image data: Figure 48, refer to the division image data Resolution: 2400dpi×2400dpi (transport direction) Number of passes: 8 times (600dpi×8) Printing direction (main scanning direction): single-direction printing Printing direction (sub-scanning direction): positive direction printing Movement distance of the nozzle row direction between each pass: 10.6μm Printing method of the pattern part except the border part: random multiple times method, refer to Figure 48 Border part printing method: block method Number of dots in the border width: 2 Printing sequence: Pattern formation method B Liquid distribution: 3.5pL across the board Nozzle temperature (temperature when ink is ejected): 75℃ Substrate temperature (temperature when ink hits): Room temperature (25℃)

≪Example 9≫ Printed material 9 was produced in the same manner as Example 2 except that the printing conditions were changed to the following conditions.

[Division printing (number of image divisions 2)] For the image data, as shown in FIG. 49, "in the image data of the pattern portion other than the boundary portion, the pixels are not overlapped when printed in an overlapping manner, and the image data is divided by the image processing software in a manner that is not in accordance with the order of rows and columns in which the pixels are arranged and does not have a certain periodicity, and the image data of the boundary portion corresponds to the block method", and the division image data No. 1 and No. 2 are produced. After that, each of the division image data is sequentially overlapped and printed under the following conditions. However, the printing direction is set to bidirectional.

Printing pattern: In a 70mm×70mm square, a 3mm×2mm blank square parallel to the main scanning direction and the sub-scanning direction is arranged Number of image divisions: 2 Image division data: Figure 49, refer to the image division data Resolution: 2400dpi×2400dpi (transport direction) Number of passes: 8 times (600dpi×8) Printing direction (main scanning direction): bidirectional printing Printing direction (sub-scanning direction): positive direction printing Movement distance of the nozzle row direction between each pass: 10.6μm Printing method of the pattern part except the border part: random multiple times method, refer to Figure 49 Border part printing method: block method Number of dots in the border width: 1 Printing sequence: Pattern formation method B Liquid distribution: 3.5pL across the board Nozzle temperature (temperature when ink is ejected): 75℃ Substrate temperature (temperature when ink hits): Room temperature (25℃)

≪Comparative Example 1≫ A printed material 10 was produced in the same manner as in Example 1 except that the printing conditions were changed to the following conditions.

Regarding the image data, as shown in FIG. 50, the pattern portion is not divided into a boundary portion and a pattern portion other than the boundary portion, but the image data used is set as one image data (not divided and printed), and all are printed in a block manner.

Printing pattern: In a 70mm×70mm square, a 3mm×2mm blank square parallel to the main scanning direction and the sub-scanning direction is arranged Resolution: 2400dpi×2400dpi (transport direction) Number of passes: 4 times (600dpi×4) Printing direction (main scanning direction): single-direction printing Printing direction (sub-scanning direction): positive direction printing Movement distance of the nozzle row direction between each pass: 10.6μm Pattern printing method: block method, refer to Figure 50 Liquid distribution: full 3.5pL Nozzle temperature (temperature when ink is ejected): room temperature (25℃) Substrate temperature (temperature when ink hits): room temperature (25℃)

≪Comparative Example 2≫ Printed material 11 was produced in the same manner as in Comparative Example 1 except that ink 1 was changed to ink 2 and the nozzle temperature (when ink is ejected) was changed to 75°C.

≪Reference Example 1≫ A printed material 12 was produced in the same manner as in Example 2 except that the printing conditions were changed to the following conditions.

[Division printing (number of image divisions 2)] As shown in FIG. 46, the image data is divided into division image data No. 1 and No. 2 by "not dividing the pattern portion into the boundary portion and the pattern portion other than the boundary portion, but dividing the entire pattern portion by image processing software in a manner that each pixel does not overlap when printed in an overlapping manner, and not in the order of rows and columns in which each pixel is arranged and not having a certain periodicity". After that, each of the division image data is sequentially overlapped and printed under the following conditions.

Printing pattern: In a 70mm×70mm square, place a 3mm×2mm blank square parallel to the main scanning direction and the sub-scanning direction Number of image divisions: 2 Division image data: Figure 46, refer to the division image data Resolution: 2400dpi×2400dpi (transport direction) Number of passes: 8 times (600dpi×8) Printing direction (main scanning direction): single-direction printing Printing direction (sub-scanning direction): positive direction printing Movement distance of the nozzle row direction between each pass: 10.6μm Pattern printing method: random multiple times, refer to Figure 46 Liquid volume distribution: full 3.5pL Nozzle temperature (temperature when ink is ejected): 75℃ Substrate temperature (temperature when ink hits): room temperature (25℃)

[Evaluation] ＜Evaluation of streaks＞ The patterns in the obtained printed materials were visually checked and the occurrence of streaks was evaluated. ◎: No streaks were found. ○: Although streaks were slightly felt, they were not particularly noticeable. ×: Since streaks were felt, it was not ideal for practical use. ××: Streaks were noticeable and difficult to use. In addition, the evaluations above ○ were considered to be no problem in practical use.

<Border Straightness (Pattern Reproducibility)> The distances between the opposite sides of the blank square (non-pattern part) of the pattern in the obtained print were measured at 20 points, and the straightness was evaluated based on the deviation between these and the arithmetic mean. ◎◎: The maximum deviation is less than 2μm. ◎: The maximum deviation is more than 2μm and less than 3μm. ○: The maximum deviation is more than 3μm and less than 5μm. △: The maximum deviation is more than 5μm and less than 10μm. ×: The maximum deviation is more than 10μm. In addition, the evaluation above △ is considered to be no problem in practical use.

The evaluation results are shown in Table I. In the table, "-" means that there is no matching data. In addition, in Figure 53, optical microscope observation photos at 100 times are shown for prints A and B, which are made under the same printing conditions as prints 2 and 12, respectively, and have four blank corners arranged parallel to the main scanning direction and the sub-scanning direction. In addition, in the optical microscope observation photos at 100 times, no matter in print A (printing conditions same as print 2) or B (printing conditions same as print 12), although some streaks are felt in the pattern part except the border part, no streaks are found visually.

According to the comparison between Example 1 and Comparative Example 1 or the comparison between Example 2 and Comparative Example 2, it can be known that in the pattern portion other than the boundary portion, by using a random multiple-time method ((I) controlling in a manner that is not in accordance with the order of rows and columns in which the pixels constituting the aforementioned image data are arranged and does not have a certain periodicity, (II) controlling in a manner that is not continuous or periodic in the main scanning direction of the aforementioned ink ejection device), the occurrence of streaks can be suppressed.

Furthermore, according to the comparison between Example 2 and Reference Example 1 and FIG. 53 , it can be known that at the boundary, by "controlling in a continuous or periodic manner according to the order of the long side direction in which each pixel constituting the aforementioned image data is arranged", the linearity at the boundary is improved.

According to the comparison of Examples 2 to 6, it can be seen that by using pattern forming method A or B (forming the coating at the points at the boundary portion is completed earlier than forming the coating at the aforementioned points at the pattern portion other than the boundary portion), the linearity at the boundary portion is further improved.

According to the comparison between Examples 2 and 9, it can be seen that due to the use of bidirectional printing (the ink ejection device moves back and forth relatively in the main scanning direction and ejects ink droplets in both the forward and return paths), although the linearity at the boundary is slightly reduced, it does not cause any practical problems, and the movement in the main scanning direction can be reduced to shorten the printing time, which has the advantage of improving productivity.

Ink 1 has a viscosity at 25°C (room temperature) that is within the appropriate viscosity range for ink ejection. Therefore, in Example 1 and Comparative Example 1, the ink is ejected at room temperature without being heated. As mentioned above, the viscosity of Ink 1 at 25°C (room temperature) is not much different from that at 75°C. Therefore, even when the print head temperature is changed to 75°C and the printed matter is produced in the same manner as in Example 1, the same result as in Example 1 (printed matter 1) can be obtained. Based on the comparison with Example 2, it can be seen that by using an ink whose ratio η2/η1 between the viscosity η1 at the temperature of discharge and the viscosity η2 at the temperature of impact is 100 or more, the linearity at the boundary is further improved. [Possibility of industrial application]

By using the pattern forming method of the present invention, a pattern without streaks and with good reproducibility can be formed. Therefore, when using ink containing a functional material such as an insulator or a conductor, a pattern with uniform insulating properties or conductive properties can be formed, and the pattern forming method of the present invention can be suitably used in pattern formation of printed circuit boards of electronic devices.

1: Inkjet printing device 2: Bracket 3: Printhead 4: X-direction linear platform 5: Table 6: Y-direction linear platform 9: Ink ejection device 11: Non-pattern part 12: Boundary forming part 13: Boundary part other than the boundary forming part 14: Pattern part other than the boundary part 15: Boundary between pattern part and non-pattern part 16: Boundary part 17: Pattern part 21~28: Nozzle 100: Inkjet printing device

[Figure 1] is a schematic diagram showing a pattern forming method by a block method. [Figure 2] is a schematic diagram showing a pattern forming method by an interlaced method. [Figure 3] is a schematic diagram showing a pattern forming method by a random multiple method of the present invention. [Figure 4] is a diagram showing image data used in the random multiple method (A). [Figure 5] is a diagram showing an example of a pattern of the present invention with blank corners arranged in the four corners. [Figure 6] is a diagram showing a grayscale image of 256 gradations that does not have a certain periodicity between adjacent pixels. [Figure 7] is a diagram showing an example of a case where the direction of the columns and rows of pixels in the image data is not parallel to the main scanning direction and the sub-scanning direction at the ink ejection device. [Figure 8A] is a schematic diagram showing an inkjet printing device caused by a multiple method (front view). [Figure 8B] is a schematic diagram showing an inkjet printing device caused by a multiple method (upper view). [Figure 9] is a diagram showing an example of a pattern of the present invention. [Figure 10] is a diagram showing an example of a boundary portion of the present invention. [Figure 11] is a diagram showing a method of using a single inkjet head with a resolution of 600 dpi to print 1200 dpi by random hits. [Figure 12] is a diagram showing one example of image data used in forming the boundary of the present invention. [Figure 13] is a diagram showing one example of a case where the boundary is a coating including points located near the boundary between the pattern portion and the non-pattern portion in addition to the boundary forming portion. [Figure 14] is a diagram showing one example of image data used in forming the boundary when the boundary is a coating including points located near the boundary between the pattern portion and the non-pattern portion in addition to the boundary forming portion. [Figure 15] is a diagram showing one example of a pattern and its boundary. [Figure 16] is a diagram showing a pattern example (rectangle) at the boundary. [Figure 17] is a diagram showing image data corresponding to the pattern case (rectangle) at the border. [Figure 18] is a diagram showing one example of the printing method (block method) for the pattern case (rectangle) at the border. [Figure 19] is a diagram showing one example (using different nozzles) of the printing method (block method) for the pattern case (rectangle) at the border. [Figure 20] is a schematic diagram of the nozzle of the ink ejection device used in one example (using different nozzles) of the printing method (block method) for the pattern case (rectangle) at the border. [Figure 21] is a diagram showing one example of the printing method (interweaving method) for the pattern case (rectangle) at the border. [Figure 22] is a diagram showing one example of a printing method (interweaving method) for a pattern case (rectangle) at the border. [Figure 23] is a diagram showing one example of a printing method (random multiple method) for a pattern case (rectangle) at the border. [Figure 24] is a diagram showing one example of a printing method (block method) for a pattern case (diamond) at the border. [Figure 25] is a diagram showing one example of a printing method (random multiple method) for a pattern case (diamond) at the border. [Figure 26] is a diagram showing image data used in a pattern forming method by segmented printing. [Figure 27A] is a diagram showing a method (1st to 8th scans) of first completing pattern formation at the boundary and then performing pattern formation at pattern portions other than the boundary (pattern formation method A). [Figure 27B] is a diagram showing a method (9th to 12th scans) of first completing pattern formation at the boundary and then performing pattern formation at pattern portions other than the boundary (pattern formation method A). [Figure 28] is a diagram showing a method (pattern formation method B) of starting pattern formation at the boundary and pattern formation at pattern portions other than the boundary at the same time and completing pattern formation at the boundary first. [Figure 29] is a diagram showing a method of printing with a resolution of 2400 dpi by random hits and split printing (number of image splits 2) using a single inkjet head with a nozzle resolution of 600 dpi. [Figure 30A] is a diagram showing a method of printing with a resolution of 2400 dpi by random hits and split printing (number of image splits 4) using a single inkjet head with a nozzle resolution of 600 dpi (1st to 8th scans). [Figure 30B] is a diagram showing a method of printing at a resolution of 2400 dpi by random hits and split printing (number of image splits 4) using a single inkjet head with a nozzle resolution of 600 dpi (9th to 16th scans). [Figure 31] is a diagram showing a method of printing at a resolution of 2400 dpi by random hits using a single inkjet head with a nozzle resolution of 600 dpi. [Figure 32] is a diagram showing the situation of "setting the same position of the point of impact of the droplets ejected from the left end nozzle and the center nozzle in the first scan and the fifth scan" in a method of printing with a resolution of 2400dpi by random hit and split printing (number of image splits 2) using a single inkjet head with a nozzle resolution of 600dpi. [Figure 33] is a top view showing the inkjet printing device 100 by the multiple-pass method. [Figure 34] is a diagram showing a method of printing by the inkjet printing device 1 (moving the nozzle in the X direction and moving the substrate in the Y direction). [Figure 35] is a diagram showing a method of printing by an inkjet printing device 100 (moving the nozzle in the Y direction and moving the substrate in the X direction). [Figure 36] is a diagram showing a method of printing by an inkjet printing device that moves the substrate in both the X direction and the Y direction. [Figure 37] is a diagram showing a method of printing by an inkjet printing device that moves the nozzle in both the X direction and the Y direction. [Figure 38] is a diagram showing a method of bidirectional printing in which "the ink ejection device relatively moves back and forth in the main scanning direction and ejects ink droplets in both the forward and return paths". [Figure 39] is a diagram showing a method of performing mixed front and back printing by "moving the ink ejection device relatively to the sub-scanning direction in a combination of the forward direction and the reverse direction". [Figure 40] is a diagram showing a method of performing split printing of a 2400 dpi resolution using a 4-nozzle inkjet head with a 600 dpi resolution. [Figure 41] is a diagram showing a printing method when the direction of the nozzle array is not perpendicular or parallel to either the X direction or the Y direction but is tilted. [Figure 42] is a diagram showing a printing method when the direction of the ink ejection device itself is not perpendicular or parallel to either the X direction or the Y direction but is tilted. [Figure 43] is a diagram showing a method (pattern forming method C) of starting pattern formation at a pattern portion other than the boundary portion first and completing pattern formation at the boundary portion and pattern formation at a pattern portion other than the boundary portion simultaneously. [Figure 44] is a diagram showing a method (pattern forming method D) of starting pattern formation at the boundary portion and pattern formation at a pattern portion other than the boundary portion simultaneously and completing them simultaneously. [Figure 45] is a diagram showing a method (pattern forming method D) of starting pattern formation at the boundary portion and pattern formation at a pattern portion other than the boundary portion simultaneously and completing them simultaneously. [Figure 46] is a diagram showing a method of forming all the patterns at the border and the pattern parts other than the border by random multiple times without changing the pattern forming method. [Figure 47] is a diagram showing a method of starting pattern formation at the border (diamond) and pattern formation at the pattern parts other than the border at the same time, and completing pattern formation at the border first (pattern forming method B). [Figure 48] is a diagram showing a method of starting pattern formation at the border (width dot number 2) and pattern formation at the pattern parts other than the border at the same time, and completing pattern formation at the border first (pattern forming method B). [Figure 49] is a diagram showing a method (pattern forming method B) in which pattern formation is performed by bidirectional printing, pattern formation at the border and pattern formation at the pattern portion other than the border are started simultaneously, and pattern formation at the border is completed first. [Figure 50] is a diagram showing a method in which the pattern portion is not divided into the border portion and the pattern portion other than the border portion, the image data used is set to one image data, and all are printed by the block method. [Figure 51] is one example of a printing method (block method) for a pattern case (gourd shape) at the border. [Figure 52] is one example of a printing method (block method, divided printing) for a pattern case (gourd shape) at the border. [Figure 53] is a photograph of prints A and B produced under the same printing conditions as prints 2 and 12, respectively, with four blank corners arranged parallel to the main scanning direction and the sub-scanning direction, observed under an optical microscope at 100 times.

Claims (10)

A method for forming a pattern is a method for forming a pattern by inkjet printing based on image data of the pattern, wherein an ink ejection device having a plurality of nozzle holes or a substrate as a printing medium is moved a plurality of times and ink droplets are ejected from the nozzles of the ink ejection device to the substrate as the printing medium to form the pattern, and the ink used in forming a coating forming dots of the pattern formed on the substrate is The droplet hits multiple times, and the position of the point where the droplet hits is controlled in a pattern portion other than the boundary portion, not in accordance with the order of rows and columns in which the pixels constituting the image data are arranged, and not in a certain periodicity, and is controlled in a continuous or periodic manner in accordance with the order of the long side direction in which the pixels constituting the image data are arranged at the boundary portion. A method for forming a pattern is a method for forming a pattern by inkjet printing based on image data of the pattern, wherein an ink ejection device having a plurality of nozzle holes or a substrate as a printing medium is moved a plurality of times and ink droplets are ejected from the nozzles of the ink ejection device to the substrate as a printing medium to form the aforementioned pattern, in the formation of a coating film constituting dots (dots) of the aforementioned pattern formed on the aforementioned substrate The landing of the droplets of the ink used covers multiple landings, and the position of the point where the droplets land is controlled in a non-continuous or periodic manner in the main scanning direction of the ink ejection device at the pattern portion other than the boundary portion, and is controlled in a continuous or periodic manner at the boundary portion in accordance with the order of the long side direction of the arrangement of the pixels constituting the image data. The pattern forming method described in claim 2, wherein the position of the aforementioned point where the aforementioned droplet hits is controlled in the aforementioned pattern portion other than the aforementioned boundary portion, and further in a manner that is not continuous or periodic in the secondary scanning direction of the aforementioned ink ejection device. A pattern forming method as recited in any one of claims 1 to 3, wherein the formation of the coating at the aforementioned points at the aforementioned boundary portion is completed earlier than the formation of the coating at the aforementioned points at the aforementioned pattern portion other than the aforementioned boundary portion. A method for forming a pattern as described in claim 2 or 3, wherein the image data of the aforementioned pattern is divided into a plurality of pieces in such a manner that the pixels do not overlap each other when overlay printing is performed and the position of the aforementioned point where the aforementioned droplet hits does not have continuity or periodicity in the aforementioned main scanning direction of the aforementioned ink ejection device, and the aforementioned divided image data is printed in sequence in an overlay manner. The pattern forming method described in claim 2 or 3, wherein the ink ejection device is relatively moved back and forth in the main scanning direction, ejecting ink droplets in both the forward path and the return path. A pattern forming method as described in any one of claim 1 to claim 3, wherein the ink used is an ink having a ratio η2/η1 of 100 or more between the viscosity η1 at the temperature when ejected and the viscosity η2 at the temperature when hit. A pattern forming method as described in any one of claims 1 to 3, wherein the aforementioned ink is a hot melt type, a gel type, or a thixotropy type ink. A pattern forming method as described in any one of claim items 1 to 3, wherein solder resist ink is used as the aforementioned ink. An inkjet printing device is an inkjet printing device that forms a pattern based on image data of the pattern, and is characterized in that the pattern is formed by a pattern forming method as described in any one of claim items 1 to 9.