JP7404695B2 - Ink discharge device, ink discharge system, and ink discharge method - Google Patents

Description

The present invention relates to an ink ejection device, an ink ejection system, and an ink ejection method.

Commercial inkjet image forming apparatuses require high-speed printing and high image quality, and techniques for transporting media such as paper or film at high speeds and techniques for scanning heads that eject ink are known.

When the medium is transported at high speed, the difference in landing time between adjacent dots during image formation becomes shorter. At this time, the ink droplets ejected from the head wet and spread on the media in a highly fluid state, and in the process of wetting and spreading, adjacent dots come into contact with each other. When dots attract each other and coalesce, the flow of ink in the direction in which the ink droplets should spread is obstructed, resulting in a problem in that the desired area of each pixel cannot be filled with ink droplets.

In such problems, for example, the ink droplets may not spread in the direction in which the dots are adjacent to each other, or the ink droplets may have difficulty spreading in the direction perpendicular to the direction in which the dots are attracted to each other. In either case, since the area that should be filled with ink cannot be filled, such areas are visually recognized as streaks. Furthermore, since the ink is unevenly distributed, it may be visually recognized as density unevenness. When such streaks and unevenness occur, image quality deteriorates.

On the other hand, for example, Patent Document 1 discloses an apparatus in which an image reproducibility improving liquid is applied to a recording medium in a straight line pattern and ink droplets are ejected.
However, in Patent Document 1, the image reproducibility improving liquid is used to suppress the wetting and spreading of ink, and does not improve the wetting and spreading of ink droplets in areas where the wetting and spreading is insufficient. Therefore, it may not be possible to sufficiently spread ink to pixels, and it is still insufficient to suppress the occurrence of streaks.

Patent Document 2 discloses an apparatus that irradiates landed droplets with an energy beam to wet and spread the droplets.
However, in Patent Document 2, since the droplet is irradiated with an energy beam, it is difficult to selectively improve the wetting and spreading of the droplet in areas where the wetting and spreading is insufficient. Therefore, it is still insufficient to suppress the occurrence of streaks.

Patent Document 3 discloses a device that reduces defects in dot shape by rotating a head to eject ink.
However, in Patent Document 3, there are parts where the ink droplets do not wet and spread sufficiently, and it is still insufficient to suppress the generation of streaks. Further, when the landing shape of the ink droplets is an ellipse, if the dots are arranged adjacent to each other in the long axis direction of the ellipse while the fluidity is high, coalescence tends to occur in the long axis direction of the ellipse. Therefore, it becomes difficult to wet and spread in the direction of the short axis of the ellipse, resulting in streaks.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an ink ejection device that can suppress streaks caused by coalescence of ink droplets.

In order to solve the above problems, an ink ejection apparatus of the present invention includes: a head that ejects ink droplets onto a medium; a moving conveyor that moves the head and the medium relatively; lyophilic pattern forming means for forming a lyophilic pattern that wets and spreads the ink droplets around a position on the medium where the ink droplets land before being ejected onto the medium; , the dynamic surface tension γ(i) [mN/m] of the ink droplet formed by a treatment liquid having affinity with the ink droplet and when the surface life of the ink droplet is 15 ms, and the surface of the treatment liquid. The dynamic surface tension γ(s) [mN/m] of the treatment liquid when the lifetime is 15 ms satisfies γ(i)<γ(s) .

According to the present invention, streaks caused by coalescence of ink droplets can be suppressed.

FIG. 1 is a schematic diagram showing an ink ejection device in an embodiment of the present invention. FIG. 7 is a diagram for explaining wetting and spreading of dots in a conventional example. FIG. 3 is a diagram for explaining wetting and spreading of dots in an embodiment of the present invention. FIG. 3 is a schematic diagram showing an ink ejection device according to another embodiment of the present invention. FIG. 7 is a diagram for explaining wetting and spreading of dots in another embodiment of the present invention. FIG. 7 is a diagram for explaining wetting and spreading of dots in another embodiment of the present invention. FIG. 3 is a schematic diagram showing an ink ejection device according to another embodiment of the present invention. FIG. 3 is a schematic diagram showing an ink ejection device according to another embodiment of the present invention. FIG. 3 is a schematic diagram showing an ink ejection device according to another embodiment of the present invention. FIG. 7 is a diagram for explaining wetting and spreading of dots in another embodiment of the present invention. 1 is a schematic diagram showing an ink ejection system in an embodiment of the present invention. FIG. 3 is a schematic diagram showing an ink ejection system in another embodiment of the present invention. FIG. 3 is a schematic diagram showing an ink ejection system in another embodiment of the present invention. FIG. 3 is a schematic diagram showing an ink ejection system in another embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An ink ejection apparatus, an ink ejection system, and an ink ejection method according to the present invention will be described below with reference to the drawings. Note that the present invention is not limited to the embodiments shown below, and may be modified within the scope of those skilled in the art, such as other embodiments, additions, modifications, deletions, etc. These are also included within the scope of the present invention as long as they exhibit the functions and effects of the present invention.

(First embodiment)
The ink ejecting apparatus of the present invention includes a head that ejects ink droplets onto a medium, a moving conveyor that moves the head and the medium relatively, and, before the head ejects the ink droplets onto the medium, a The present invention is characterized by comprising a lyophilic pattern forming means for forming a lyophilic pattern around a position on the media where the ink droplets land by wetting and spreading the ink droplets.

FIG. 1 shows an ink ejection device of this embodiment. In FIG. 1, a media 11, a moving conveyance means 12, a head 13, and a lyophilic pattern forming means 14 are illustrated.

The arrow X in the figure indicates the conveyance direction of the media (hereinafter sometimes simply referred to as the conveyance direction), and the lyophilic pattern forming means 14 is arranged upstream of the head 13 in the conveyance direction. There is.

Examples of the media 11 include paper, film, and cloth.
In the example shown in FIG. 1, a roll of continuous paper is used.

The head 13 discharges ink droplets onto the medium 11, and may be an inkjet head, for example. In this case, the ink ejection device can be used as an inkjet recording device or the like. Details of the ink will be explained in the embodiment described later.

The moving conveyance means 12 (also referred to as a moving conveyance mechanism, a moving conveyance device, a media conveyance mechanism, etc.) moves the head 13 and the media 11 relatively. Although it is possible to change it as appropriate, for example, a roller for conveying the media 11 can be used. Note that although the following description uses movement and conveyance, unless otherwise specified, the description will be made without strictly distinguishing between the two.

The moving conveyance means may move and convey the head and the medium at the same time, or may move and convey either the head or the medium.
The moving conveyance means 12 in this embodiment conveys the media 11 without causing the head 13 to scan. Such a method is also called a single-pass method. The present invention is not limited to the single-pass method, but also includes a method of scanning the head (also referred to as a multi-pass method).

The lyophilic pattern forming means 14 (also referred to as a lyophilic pattern forming device, a lyophilic pattern applying means, a lyophilic pattern applying device, etc.) can be modified as appropriate, and for example, a processing liquid may be used. Examples include a method of forming recesses in the media using a mold, a method of heating the media by laser irradiation, and a method of surface modification of the media by plasma, laser irradiation, etc.

Although not limited to this, this embodiment uses an online method. In the online method, for example, the head 13 and the lyophilic pattern forming means 14 are incorporated into an ink ejection device, and the distance between the head 13 and the lyophilic pattern forming means 14 and the conveyance speed of the medium are detected. Thereby, the ink droplet can be landed at a targeted position on the media on which the lyophilic pattern is formed.

In the present invention, as will be described later, a method may be adopted in which the lyophilic pattern forming means 14 is not incorporated into the ink ejection apparatus (also referred to as an offline method). In the offline method, a lyophilic pattern is formed by a lyophilic pattern forming device, and the ink ejection device and the lyophilic pattern forming device are configured separately.

Here, a conventional example will be explained using FIG. 2. FIG. 2 is a diagram for explaining the wetting and spreading of dots when two consecutive dots are printed in the conveyance direction (X direction) of the medium. The example shown here is an example using a single-pass method in which the head position is fixed and the media is transported at high speed.This is an example in which dots are adjacent to each other in the media transport direction by continuous ejection using the same nozzle. be. Note that here, a dot corresponds to an ink droplet, and one dot corresponds to one ink droplet.

FIG. 2A shows an example in which the ink droplets land in a circular shape, and FIG. 2B shows an example in which the ink droplets land in an elliptical shape. The landing shape of ink droplets may vary depending on the media conveyance speed and the like.

First, FIG. 2(a) will be explained. FIG. 2A shows an example in which ink droplets are landed on pixels 21a adjacent to each other in the media transport direction. As shown in the figure, the ink droplet is landed at the center of the pixel 21a. Reference numeral 22a represents the shape of the ink droplet landing, and reference numeral 23a represents the contour shape of two dots when the ink droplet wets and spreads after landing.

Note that a pixel is, for example, the smallest unit of a square that constitutes an image, and is also referred to as a pixel. Further, in the figure, an arrow Y indicates the row direction of the nozzles, and in this embodiment, as an example, the X direction and the Y direction are perpendicular to each other, but the present invention is not limited to this. The X direction and the Y direction may be at angles other than 90 degrees.

In the conventional example shown here, in the media conveyance direction, an ink droplet (preceding droplet) first lands on the area of the pixel 21a on the lower side of the paper surface, and as it spreads, the next ink droplet lands on the area of the pixel 21a on the upper side of the paper surface. Droplets (trailing drops) land and spread wet. Generally, the shorter the difference in landing time, the higher the fluidity of the ink and the more adjacent two droplets come into contact during the process of wetting and spreading. Therefore, the media tend to coalesce and come together in the media transport direction.

The example shown in FIG. 2(a) shows the non-uniformity of wetting and spreading when a trailing droplet wets and spreads and comes into contact with a leading droplet, and then is drawn into the leading droplet and coalesces. Leading droplets wet and spread uniformly in the media transport direction, but trailing droplets become difficult to wet and spread in the opposite direction to the media transport direction when they are drawn into the leading droplet. Further, both the leading droplet and the trailing droplet are less likely to wet and spread in the nozzle row direction (Y direction).

In FIG. 2A, the arrows shown around the ink droplet landing shape 22a indicate the direction in which the ink droplet spreads, and the length of the arrow indicates the speed at which the ink droplet spreads. The above-mentioned non-uniformity is also represented using the length of the arrow. For example, the arrow from the trailing drop to the leading drop is illustrated as being long, representing that the trailing drop is drawn into the leading drop. Furthermore, the fact that this reduces the spread of wetting in the nozzle row direction is also expressed by the length of the arrow.

When two ink droplets that are adjacent to each other in the media transport direction are attracted to each other, the amount of ink flowing in the nozzle row direction at the pixel decreases accordingly, resulting in insufficient wetting and spreading in the nozzle row direction, and the area filled with ink. is in short supply. Therefore, the contour shape of the two dots in a state where the wetting and spreading becomes uneven becomes a shape as shown by reference numeral 23a, and the pixels cannot be sufficiently covered. If a solid image is formed in this state, lines of discontinuous dots will be lined up in the nozzle row direction in the media transport direction. This is visually recognized as a stripe, and when the stripe occurs, the image quality deteriorates.

Next, another conventional example shown in FIG. 2(b) will be explained. FIG. 2(b) is similar to FIG. 2(a), but is an example in which the ink droplet landing shapes 22b are elliptical and unified. Note that, similarly to FIG. 2A, the arrows shown around the ink droplet landing shape 22b indicate the direction in which the ink droplet spreads, and the length of the arrow represents the speed at which the ink droplet spreads. There is.

Normally, ink droplets are ejected vertically below the media plane and fly, but when the media is transported at a sufficiently high speed than the flying speed of the ink droplets, the landing shape of the ink droplets becomes an ellipse with its long axis in the media transport direction. It may take shape.

If there is only one droplet with no surrounding ink droplets, it will spread over time and become circular. However, as shown in FIG. 2(b), when two or more ink droplets land in an elliptical shape and are adjacent to each other in the media transport direction, the distance between dots in the media transport direction is smaller than when the impact shape is circular. It is short and contacts quickly in the media transport direction.

For this reason, the ink droplets stick together and are attracted to each other in the media transport direction in a highly fluid state before drying. On the other hand, in the direction of the nozzle rows, it becomes more difficult to wet and spread, so the area covering the pixels becomes insufficient in the direction of the nozzle rows of the pixels. As illustrated, the contour shape 23b cannot sufficiently cover the pixels. If a solid image is printed in this state, image quality deterioration such as visible streaks in the media transport direction becomes a problem.

Next, details of this embodiment will be explained.
FIGS. 3(a) and 3(b) show diagrams for explaining this embodiment. Similar to FIG. 2, FIGS. 3A and 3B are diagrams for explaining the wetting and spreading of dots when two consecutive dots are printed in the conveyance direction of the medium. FIG. 3A shows an example in which the ink droplets land in a circular shape, and FIG. 3B shows an example in which the ink droplets land in an elliptical shape.

Note that, like the example shown in FIG. 2, the example shown in FIG. 3 is an example in which an online method is used, and a single-pass method is used.

In FIG. 3, pixels 31a, 31b, ink droplet landing shapes 32a, 32b, outline shapes 33a, 33b, and lyophilic patterns 34a, 34b, 35a are shown. Here, since the pixels are adjacent to each other in the media transport direction, the ink droplets coalesce in the media transport direction, forming two dot outlines 33a and 33b that wet and spread.

First, an example shown in FIG. 3(a) in this embodiment will be described. In this embodiment, the lyophilic pattern is not formed at the position where the ink droplet lands, but the lyophilic patterns 34a and 35a are formed around the position where the ink droplet lands to wet and spread the ink droplet. Wetting and spreading of the ink is promoted in areas where the wetting and spreading of the ink is insufficient. As a result, as shown by the outline shape 33a, the coalescing dots spread out in a desired shape, and it is possible to suppress streaks caused by the coalescence of ink droplets.

In FIG. 3(a), lyophilic patterns 34a and 35a are formed as lyophilic patterns, and the lyophilic pattern 34a promotes wetting and spreading in the nozzle row direction (Y direction), and is lyophilic. The pattern 35a promotes wetting and spreading in the media transport direction (X direction).

The size (area) of the lyophilic pattern can be changed as appropriate, and in this example, the lyophilic pattern 35a is made larger than the lyophilic pattern 34a. For example, if an ink droplet (trailing droplet) that lands on the pixel 31a area on the upper side of the page is pulled by an ink droplet (leading droplet) that lands on the pixel 31a area on the lower side of the page, the trailing droplet will be moved in the media transport direction. The lyophilic pattern 35a is made wide for the purpose of quickly wetting and spreading in the opposite direction.

The lyophilic pattern is formed around the position on the media where the ink droplets land. Here, the area around the position where an ink droplet lands means an area at a distance where the landed ink droplet can come into contact with the area when it wets and spreads. The area around the position where the ink droplets land is changed as appropriate depending on the droplet volume of the ink droplets, the flight speed of the ink droplets, the type of media, the conveyance speed of the media, and the like.

Also, although it is written as "surroundings", the lyophilic pattern does not need to be formed on both sides of the media transport direction and both sides of the nozzle row direction with respect to the position where the ink droplets land, and may be formed as appropriate. It is possible to change. For example, in the case of an ink droplet (preceding droplet) that lands on a pixel on the lower side of the paper in FIG. This is included when the area is formed around the location where the area is located.

In this embodiment, the moving conveyance means conveys the media, and the lyophilic pattern forming means forms a lyophilic pattern in an area adjacent to a position where an ink droplet lands in a direction perpendicular to the conveyance direction of the media. It is something that forms.

The area where the lyophilic pattern is formed can be changed as appropriate, but considering that the pixel will be covered with ink droplets, it is possible to form the lyophilic pattern not only inside the pixel but also outside the pixel. It is preferable that

The shape of the lyophilic pattern is not limited to the rectangle shown, but may be polygonal, circular, or other shapes. It is preferable to change the shape of the lyophilic pattern as appropriate depending on the area and shape where wetting and spreading are insufficient. Further, the number of lyophilic patterns corresponding to one ink droplet can also be changed as appropriate.

The lyophilic pattern 34a is not limited to the case where the long sides of the rectangle are parallel to the nozzle row direction, but may be inclined with respect to the media conveyance direction or the nozzle row direction, for example, at an angle of 45 degrees. Furthermore, the line segments connecting the lyophilic patterns 34a across the landing positions of the ink droplets are not limited to being parallel to the nozzle row direction, but may be inclined with respect to the media conveyance direction or the nozzle row direction. .

The lyophilic pattern forming means may form the lyophilic pattern around the position where the ink droplets land only when the ejection conditions are such that the ink droplets land on adjacent pixels. If there is only one ink droplet and there are no adjacent dots, streaks are unlikely to occur due to the coalescence of ink droplets, so if two or more dots are adjacent to each other in the media transport direction or nozzle row direction, it is determined from the image data, etc. The lyophilic pattern may be formed only on each dot.

In this case, by not forming a lyophilic pattern compared to the case of one dot, the process for forming a lyophilic pattern can be reduced, and costs can be suppressed. For example, when a lyophilic pattern is formed using a processing liquid such as a lyophilic material, the amount of processing liquid used can be reduced by reducing the number of locations where the processing liquid is used, and costs can be suppressed. Furthermore, when forming a lyophilic pattern by laser irradiation, energy consumption can be suppressed by reducing the number of laser irradiated locations.

Methods for forming lyophilic patterns include, for example, a method using a treatment liquid, a method of forming recesses in the media using a mold, a method of heating the media with laser irradiation, and a method of surface modification of the media with plasma, laser, etc. Examples include a method to do so. Details will be explained in later embodiments.

As described above, according to the present embodiment, a lyophilic pattern can be applied to a region where the wetting and spreading of ink droplets is insufficient due to coalescence, and the ink droplets can be preferentially wetted and spread. Furthermore, according to the present embodiment, it is possible to fill the pixel area in the media conveyance direction and nozzle row direction that could not be filled with ink due to insufficient wetting and spreading in the conventional example shown in FIG. 2(a), for example. , it is possible to reduce streaks and improve image quality.

Furthermore, when forming a lyophilic pattern around the position where an ink droplet lands as in the present embodiment, compared to the conventional technique, for example, Patent Document 1 in which a treatment liquid is applied using a line-based method, for example, the treatment When forming a lyophilic pattern with a liquid, the area required for the treatment liquid can be reduced, so the amount of treatment liquid used can be suppressed.

Furthermore, according to the present embodiment, even if the landing position varies due to variations in ejection conditions or wettability of the media, if it comes into contact with the lyophilic pattern during the wetting and spreading process, it will wet and spread on the lyophilic pattern. , it is possible to fill in areas that would otherwise have been streaked. In addition, by applying a lyophilic pattern not to the entire surface of the media, but to areas where dots do not wet and spread insufficiently, it is possible to reduce the amount of lyophilic material used and the thermal energy required for drying in the post-process. .

Note that when the lyophilic pattern is formed by printing a lyophilic material on a medium by inkjet or gravure printing, it is preferable to form the lyophilic pattern so as not to overlap the ink landing area. Thereby, the amount of lyophilic material can be reduced.

Next, an example shown in FIG. 3(b) in this embodiment will be explained.
FIG. 3(b) is an example similar to FIG. 3(a), except that the ink droplet landing shapes 32b are elliptical and unified.

In the example shown in FIG. 3(b), the nozzle row direction (Y direction), which is the short axis direction of the ellipse when an ink droplet lands, has priority over the media transport direction (X direction), which is the long axis direction of the ellipse. The lyophilic pattern 34b is formed for the purpose of making the liquid wet and spread. Therefore, even if the ink droplet has an elliptical shape at the time of landing, the ink droplet wets and spreads on the lyophilic pattern 34b during the wetting and spreading process after landing. That is, by forming a lyophilic pattern in a region where wetting and spreading is insufficient, wetting and spreading of the ink is promoted.

As a result, it is possible to fill the pixel area in the nozzle row direction that could not be filled with ink due to insufficient wetting and spreading in the conventional example shown in FIG. 2(b), for example, and improve streaks. Image quality can be improved.

Also in this example, the formation location, shape, etc. of the lyophilic pattern can be changed as appropriate in the same manner as in FIG. 3(a) described above. In addition, two or more lyophilic patterns may be formed around the landing position of an ink droplet in the media transport direction for each pixel.

Also in this example, the lyophilic pattern may be formed around the ink droplets only when the ejection conditions are such that the ink droplets land on adjacent pixels. If there is only one ink droplet and there are no adjacent dots, even if the ink droplet is elliptical when it lands, it often becomes circular over time. Therefore, by determining from the image data whether two or more dots are adjacent in the media transport direction or the nozzle row direction, a lyophilic pattern may be formed only for each corresponding dot. In this case, processing can be reduced by not forming a lyophilic pattern compared to the case of one dot.

As described above, the present embodiment provides an ink ejection method that can suppress streaks caused by coalescence of ink droplets.
The ink ejection method of the present embodiment includes an ink drop ejection step in which a head ejects ink droplets onto a medium, a movement conveyance step in which the head and the medium are relatively moved, and a step in which the head ejects the ink droplets onto the medium. The method includes a lyophilic pattern forming step of forming a lyophilic pattern that wets and spreads the ink droplets around a position on the medium where the ink droplets land before ejecting.

The ink droplet ejection process can be performed using the above-mentioned head, and the lyophilic pattern can be formed using the above-mentioned lyophilic pattern forming means.

(Second embodiment)
Other embodiments of the ink ejection device according to the present invention will be described.
Description of matters similar to those in the above embodiment will be omitted.

The ink ejection device of this embodiment will be explained using FIG. 4.
FIG. 4A is a diagram schematically showing a surface of the head 41 that faces the media (also referred to as an ejection surface). In the head in this embodiment, nozzle rows A to D are formed, and n nozzles are formed in each nozzle row direction (Y direction). The A and B rows, the C and D rows are arranged in a staggered manner, and the A and B rows and the C and D rows are staggered in the direction of the nozzle rows. Further, the distance between the B row and the C row is longer than that between the A row and the B row and between the C row and the D row in order to increase the difference in impact time in the direction of the nozzle rows.

FIG. 4B is a diagram for explaining the wetting and spreading of dots when nozzle A1 prints two consecutive dots in the media transport direction and nozzle C1 prints one dot. In the figure, a pixel 42, an ink droplet landing shape 43, lyophilic patterns 44a, 44b, 44c, and an outline shape 45 of a wetting and spreading coalescing dot are shown, and three droplets are adjacent in the media transport direction and the nozzle row direction. This is an example of a lyophilic pattern when

Ejection is performed using the nozzle A1 and the nozzle C1 in the head 41, and when three droplets are adjacent to each other as shown in FIG. 4(B), the ink droplets land in the numerical order shown in the ink droplet landing shape 43 indicated by the broken line. Here, the circled numbers 1 to 3 are expressed as (1) to (3). The first drop (1) and the second drop (2) are ejected from nozzle A1, and after a delay corresponding to the distance of the nozzle arrangement, the third drop (3) is ejected to the adjacent pixel in the nozzle row direction of the first drop (1). be done.

Here, the lyophilic pattern 44a is formed in a region adjacent to the landing position of the ink droplet in the nozzle row direction. The lyophilic pattern 44b is formed in the area between the first drop (1) and the third drop (3), and the lyophilic pattern 44c is formed at the landing position of the third drop (3). It is formed in an adjacent region in the nozzle row direction at a position opposite to that of the first drop (1).

Considering the pattern shape of the lyophilic pattern 44a as a reference, the lyophilic pattern 44b spanning pixels adjacent in the nozzle row direction has the same shape as the lyophilic pattern 44a, but Since it is necessary to control the spreading speed, the lyophilic pattern 44a and the lyophilic pattern 44b do not necessarily have to have the same shape. Furthermore, the lyophilic pattern 44c has a pattern shape whose area is expanded in the media transport direction.

As shown in the illustrated lyophilic pattern 44b, it is preferable to form the lyophilic pattern in a region spanning the boundaries between adjacent pixels. As a result, two pixels adjacent in the nozzle row direction can be seamlessly filled with ink, making it possible to further suppress the occurrence of streaks and reduce the amount of ink droplets used.

In the example shown in Fig. 4(B), the wetting and spreading of one ink droplet has not reached enough to fill a pixel, or the landing position of the third drop (3) is slightly to the right (one drop It is assumed that the image is deviated in the direction away from the eye (1). In such a case, with the prior art, it was necessary to use large ink droplets to fill the pixels. On the other hand, according to this embodiment in which the lyophilic pattern 44b is formed, the third drop (3) is pulled to the left side of the pixel (towards the first drop (1)), so it is not necessary to make the droplet large as in the conventional technology. Therefore, the amount of ink used can be reduced.

When ink droplets (1) to (3) are ejected as shown in FIG. 4(B), the third droplet (3) is a droplet that has already wetted and spread in the process of spreading on the lyophilic pattern 44b. When it comes into contact with the eye (1), it becomes more likely to be drawn toward the first drop (1). For this reason, the amount of ink that wets and spreads on the right side of the paper (opposite side from the first drop (1)) in the direction of the nozzle row of the third drop (3) decreases, making it impossible to fill the pixels with ink.

Therefore, in this embodiment, the area is expanded in the media transport direction like the lyophilic pattern 44c in order to quickly wet and spread in the direction opposite to the drawing direction. In the process of the third drop (3) spreading, the lyophilic pattern 44C can draw the third drop (3) into a wide boundary, so the third drop (3) moves in the opposite direction to the first drop (1). It can wet and spread quickly, preventing the amount of ink from decreasing and filling pixels with ink.

The shape of the lyophilic pattern 44c is determined by the balance between the speed at which the third drop (3) spreads on the surface of the first drop (1) and the speed at which it is drawn in, and the speed at which the third drop (3) wets and spreads on the media where no preceding drop exists. It is preferable to change it as appropriate. The balance of the speed of wetting and spreading varies depending on the physical state of the first drop (1), which is affected by the physical properties of the ink, the rate of penetration and evaporation of the ink, the difference in landing time, etc., and the type of media. It is preferable to take this into account and adjust accordingly.

Also in this embodiment, the shape and the like of the lyophilic pattern can be changed as appropriate, similar to the above embodiments.

(Third embodiment)
Next, a method for forming a lyophilic pattern in the present invention will be described by taking one embodiment as an example. Here, detailed examples of the ink and treatment liquid used in the present invention will be described.

As described above, in the present invention, the method for forming a lyophilic pattern and the configuration of the lyophilic pattern forming means can be changed as appropriate. For example, methods of applying a treatment liquid such as a lyophilic material, methods of forming recesses in the media using a mold, methods of creating a temperature difference in the media by irradiating laser, and surface treatments such as plasma treatment and corona treatment. Examples include a method of modification.
Among these, in this embodiment, a method using a treatment liquid will be described. Note that the configuration of the ink ejection device is the same as that in the first embodiment.

The lyophilic pattern in this embodiment is formed by a treatment liquid that has an affinity for ink droplets. Furthermore, the lyophilic pattern forming means in this embodiment applies a treatment liquid to the media.
According to the present embodiment, by applying a treatment liquid with high affinity for ink in advance in a direction where wetting and spreading are insufficient, streaks caused by coalescence of ink droplets can be reduced, and the amount of ink used can be suppressed. Deterioration in image quality due to the occurrence of streaks can be suppressed.

Examples of the method for applying the treatment liquid to the media by the lyophilic pattern forming means include an inkjet method, gravure printing, and the like.

Note that when the processing liquid is ejected using an inkjet method in an online method, test printing may be performed. At this time, it is preferable to create in advance lyophilic pattern ejection data for ejecting a lyophilic pattern to a location where ink droplets are desired to be wetted and spread by identifying abnormal nozzles from streaks caused by ejection curvature.

<Ink>
The organic solvent, water, coloring material, resin, additives, etc. used in the ink will be explained below.

<Resin>
The type of resin contained in the ink is not particularly limited and can be selected as appropriate depending on the purpose.For example, urethane resin, polyester resin, acrylic resin, vinyl acetate resin, styrene resin, butadiene resin. Examples include resins, styrene-butadiene resins, vinyl chloride resins, acrylic styrene resins, acrylic silicone resins, and the like.
Resin particles made of these resins may also be used. It is possible to obtain ink by mixing resin particles with materials such as colorants and organic solvents in the state of a resin emulsion in which resin particles are dispersed using water as a dispersion medium. As the resin particles, those synthesized as appropriate may be used, or commercially available products may be used. Further, these may be used alone or in combination of two or more types of resin particles.

The volume average particle diameter of the resin particles is not particularly limited and can be appropriately selected depending on the purpose, but from the viewpoint of obtaining good fixing properties and high image hardness, it is preferably 10 nm or more and 1,000 nm or less, and 10 nm or more. It is more preferably 10 nm or more and 100 nm or less, and particularly preferably 10 nm or more and 100 nm or less.
The volume average particle diameter can be measured, for example, using a particle size analyzer (Nanotrac Wave-UT151, manufactured by Microtrac Bell Co., Ltd.).

The content of the resin is not particularly limited and can be selected as appropriate depending on the purpose, but from the viewpoint of fixing properties and storage stability of the ink, it is 1% by mass or more and 30% by mass or less based on the total amount of ink. is preferable, and more preferably 5% by mass or more and 20% by mass or less.

<Color material>
The coloring material is not particularly limited, and pigments and dyes can be used.
As pigments, inorganic pigments or organic pigments can be used. These may be used alone or in combination of two or more. Further, a mixed crystal may be used as the pigment.
Examples of pigments that can be used include black pigments, yellow pigments, magenta pigments, cyan pigments, white pigments, green pigments, orange pigments, glossy pigments such as gold and silver, and metallic pigments.
Inorganic pigments include titanium oxide, iron oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, cadmium red, and chrome yellow, as well as carbon black produced by known methods such as contact method, furnace method, and thermal method. can be used.
Examples of organic pigments include azo pigments, polycyclic pigments (e.g., phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, indigo pigments, thioindigo pigments, isoindolinone pigments, quinophthalone pigments, etc.) , dye chelates (eg, basic dye type chelates, acidic dye type chelates, etc.), nitro pigments, nitroso pigments, aniline black, etc. can be used. Among these pigments, those having good affinity with the solvent are preferably used. In addition, resin hollow particles and inorganic hollow particles can also be used.
Specific examples of pigments for black include carbon blacks (C.I. Pigment Black 7) such as furnace black, lamp black, acetylene black, and channel black, or copper and iron (C.I. Pigment Black 11). , metals such as titanium oxide, and organic pigments such as aniline black (C.I. Pigment Black 1).
Furthermore, for color use, C. I. Pigment Yellow 1, 3, 12, 13, 14, 17, 24, 34, 35, 37, 42 (yellow iron oxide), 53, 55, 74, 81, 83, 95, 97, 98, 100, 101, 104 , 108, 109, 110, 117, 120, 138, 150, 153, 155, 180, 185, 213, C. I. Pigment Orange 5, 13, 16, 17, 36, 43, 51, C. I. Pigment Red 1, 2, 3, 5, 17, 22, 23, 31, 38, 48:2, 48:2 (Permanent Red 2B (Ca)), 48:3, 48:4, 49:1, 52: 2, 53:1, 57:1 (Brilliant Carmine 6B), 60:1, 63:1, 63:2, 64:1, 81, 83, 88, 101 (Red), 104, 105, 106, 108 ( cadmium red), 112, 114, 122 (quinacridone magenta), 123, 146, 149, 166, 168, 170, 172, 177, 178, 179, 184, 185, 190, 193, 202, 207, 208, 209, 213, 219, 224, 254, 264, C. I. Pigment Violet 1 (Rhodamine Lake), 3, 5:1, 16, 19, 23, 38, C.I. I. Pigment Blue 1, 2, 15 (phthalocyanine blue), 15:1, 15:2, 15:3, 15:4 (phthalocyanine blue), 16, 17:1, 56, 60, 63, C.I. I. There are pigment greens 1, 4, 7, 8, 10, 17, 18, 36, etc.
The dye is not particularly limited, and acid dyes, direct dyes, reactive dyes, and basic dyes can be used, and one type may be used alone or two or more types may be used in combination.
As a dye, for example, C.I. I. Acid Yellow 17, 23, 42, 44, 79, 142, C. I. Acid Red 52, 80, 82, 249, 254, 289, C. I. Acid Blue 9,45,249, C. I. Acid Black 1, 2, 24, 94, C. I. Food black 1, 2, C. I. Direct Yellow 1, 12, 24, 33, 50, 55, 58, 86, 132, 142, 144, 173, C. I. Direct Red 1, 4, 9, 80, 81, 225, 227, C. I. Direct Blue 1, 2, 15, 71, 86, 87, 98, 165, 199, 202, C. I. Directed Black 19, 38, 51, 71, 154, 168, 171, 195, C. I. Reactive Red 14, 32, 55, 79, 249, C. I. Examples include Reactive Black 3, 4, and 35.

The content of the coloring material in the ink is preferably 0.1% by mass or more and 15% by mass or less, more preferably 1% by mass or more and 10% by mass, from the viewpoint of improving image density, good fixing properties, and ejection stability. It is as follows.

Methods for obtaining ink by dispersing pigments include introducing hydrophilic functional groups into the pigment to make it a self-dispersing pigment, coating the surface of the pigment with a resin and dispersing it, and dispersing it using a dispersant. methods, etc.
An example of a method of introducing a hydrophilic functional group into a pigment to make it a self-dispersing pigment is to add a functional group such as a sulfone group or a carboxyl group to a pigment (for example, carbon) to make it dispersible in water. can be mentioned.
Examples of methods for coating the surface of pigments with resin and dispersing them include a method in which the pigments are encapsulated in microcapsules and made dispersible in water. This can be referred to as a resin-coated pigment. In this case, all the pigments blended into the ink do not need to be coated with the resin, and uncoated pigments or partially coated pigments may be dispersed in the ink as long as the effects of the present invention are not impaired. You can leave it there.
Examples of the method for dispersing using a dispersant include methods for dispersing using known low-molecular-type dispersants and polymer-type dispersants, typified by surfactants.
As the dispersant, it is possible to use, for example, an anionic surfactant, a cationic surfactant, an amphoteric surfactant, a nonionic surfactant, etc. depending on the pigment.
As a dispersant, RT-100 (nonionic surfactant) manufactured by Takemoto Yushi Co., Ltd. and a formalin condensate of naphthalene sulfonate can also be suitably used as a dispersant.
One type of dispersant may be used alone, or two or more types may be used in combination.

<Pigment dispersion>
Ink can be obtained by mixing pigments with materials such as water and organic solvents. It is also possible to manufacture ink by mixing a pigment with other materials such as water and a dispersant to form a pigment dispersion, and then mixing materials such as water and an organic solvent.
The pigment dispersion is obtained by mixing and dispersing water, a pigment, a pigment dispersant, and other components as necessary, and adjusting the particle size. For dispersion, it is best to use a disperser.
There is no particular restriction on the particle size of the pigment in the pigment dispersion, but the maximum frequency in terms of the maximum number of particles should be 20 nm or more, since the dispersion stability of the pigment is good and the image quality such as ejection stability and image density is also high. The thickness is preferably 500 nm or less, more preferably 20 nm or more and 150 nm or less. The particle size of the pigment can be measured using a particle size analyzer (Nanotrac Wave-UT151, manufactured by Microtrac Bell Co., Ltd.).
The content of pigment in the pigment dispersion is not particularly limited and can be appropriately selected depending on the purpose, but from the viewpoint of obtaining good ejection stability and increasing image density, 0.1% by mass It is preferably 50% by mass or less, more preferably 0.1% by mass or more and 30% by mass or less.
It is preferable to filter coarse particles from the pigment dispersion using a filter, a centrifugal separator, etc. and degas the pigment dispersion, if necessary.

<Organic solvent>
The organic solvent used in the present invention is not particularly limited, and water-soluble organic solvents can be used. Examples include polyhydric alcohols, ethers such as polyhydric alcohol alkyl ethers and polyhydric alcohol aryl ethers, nitrogen-containing heterocyclic compounds, amides, amines, and sulfur-containing compounds.
Specific examples of polyhydric alcohols include ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butane Diol, 2,3-butanediol, 3-methyl-1,3-butanediol, triethylene glycol, polyethylene glycol, polypropylene glycol, 1,2-pentanediol, 1,3-pentanediol, 1,4-pentanediol , 2,4-pentanediol, 1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 1,3-hexanediol, 2,5-hexanediol, 1,5-hexanediol, Glycerin, 1,2,6-hexanetriol, 2-ethyl-1,3-hexanediol, ethyl-1,2,4-butanetriol, 1,2,3-butanetriol, 2,2,4-trimethyl- Examples include 1,3-pentanediol and petriol.
Examples of polyhydric alcohol alkyl ethers include ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, propylene glycol monoethyl ether, and the like.
Examples of polyhydric alcohol aryl ethers include ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether.
Examples of nitrogen-containing heterocyclic compounds include 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, ε-caprolactam, and γ-butyrolactone. Can be mentioned.
Examples of amides include formamide, N-methylformamide, N,N-dimethylformamide, 3-methoxy-N,N-dimethylpropionamide, 3-butoxy-N,N-dimethylpropionamide, and the like.
Examples of amines include monoethanolamine, diethanolamine, triethylamine, and the like.
Examples of the sulfur-containing compounds include dimethyl sulfoxide, sulfolane, thiodiethanol, and the like.
Other organic solvents include propylene carbonate, ethylene carbonate, and the like.
It is preferable to use an organic solvent with a boiling point of 250° C. or lower because it not only functions as a wetting agent but also provides good drying properties.

As the organic solvent, polyol compounds having 8 or more carbon atoms and glycol ether compounds are also preferably used. Specific examples of polyol compounds having 8 or more carbon atoms include 2-ethyl-1,3-hexanediol and 2,2,4-trimethyl-1,3-pentanediol.
Specific examples of glycol ether compounds include polyhydric alcohol alkyls such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, and propylene glycol monoethyl ether. Ethers: Examples include polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether.

A polyol compound having 8 or more carbon atoms and a glycol ether compound can improve the permeability of ink when paper is used as a recording medium.

The content of the organic solvent in the ink is not particularly limited and can be appropriately selected depending on the purpose, but from the viewpoint of ink drying properties and ejection reliability, it is preferably 10% by mass or more and 60% by mass or less, More preferably 20% by mass or more and 60% by mass or less.

<Water>
The water content in the ink is not particularly limited and can be appropriately selected depending on the purpose, but from the viewpoint of ink drying properties and ejection reliability, it is preferably 10% by mass or more and 90% by mass or less, and 20% by mass or less. % or more and 60% by mass or less is more preferable.

<Additives>
A surfactant, an antifoaming agent, a preservative and fungicide, a rust preventive, a pH adjuster, and the like may be added to the ink as necessary.

<Surfactant>
As the surfactant, any of silicone surfactants, fluorine surfactants, amphoteric surfactants, nonionic surfactants, and anionic surfactants can be used.
The silicone surfactant is not particularly limited and can be appropriately selected depending on the purpose. Among these, those that do not decompose even at high pH are preferred. Examples of the silicone surfactant include side chain-modified polydimethylsiloxane, both end-modified polydimethylsiloxane, one-end modified polydimethylsiloxane, and side-chain both end-modified polydimethylsiloxane. Particularly preferred are those having a polyoxyethylene group or a polyoxyethylene polyoxypropylene group as a modified group, since they exhibit good properties as a water-based surfactant. Further, as the silicone surfactant, a polyether-modified silicone surfactant can also be used, such as a compound in which a polyalkylene oxide structure is introduced into the side chain of the Si part of dimethylsiloxane.
Examples of fluorine-based surfactants include perfluoroalkyl sulfonic acid compounds, perfluoroalkyl carboxylic acid compounds, perfluoroalkyl phosphate ester compounds, perfluoroalkyl ethylene oxide adducts, and perfluoroalkyl ether groups in their side chains. Polyoxyalkylene ether polymer compounds are particularly preferred because they have low foaming properties. Examples of the perfluoroalkylsulfonic acid compound include perfluoroalkylsulfonic acid, perfluoroalkylsulfonic acid salts, and the like. Examples of the perfluoroalkylcarboxylic acid compound include perfluoroalkylcarboxylic acids, perfluoroalkylcarboxylic acid salts, and the like. Examples of polyoxyalkylene ether polymer compounds having perfluoroalkyl ether groups in their side chains include sulfate ester salts of polyoxyalkylene ether polymers having perfluoroalkyl ether groups in their side chains, and polyoxyalkylene ether polymers having perfluoroalkyl ether groups in their side chains. Examples include salts of oxyalkylene ether polymers. Counter ions of the salts in these fluorosurfactants include Li, Na, K, NH ₄ , NH ₃ CH ₂ CH ₂ OH, NH ₂ (CH ₂ CH ₂ OH) ₂ , NH (CH ₂ CH ₂ OH) _3rd prize is mentioned.
Examples of the amphoteric surfactant include lauryl aminopropionate, lauryl dimethyl betaine, stearyl dimethyl betaine, lauryl dihydroxyethyl betaine, and the like.
Examples of nonionic surfactants include polyoxyethylene alkylphenyl ether, polyoxyethylene alkyl ester, polyoxyethylene alkylamine, polyoxyethylene alkylamide, polyoxyethylene propylene block polymer, sorbitan fatty acid ester, polyoxyethylene sorbitan Examples include fatty acid esters and ethylene oxide adducts of acetylene alcohol.
Examples of the anionic surfactant include polyoxyethylene alkyl ether acetate, dodecylbenzene sulfonate, laurate, polyoxyethylene alkyl ether sulfate salt, and the like.
These may be used alone or in combination of two or more.

The silicone surfactant is not particularly limited and can be selected as appropriate depending on the purpose, but examples include side chain-modified polydimethylsiloxane, double-end modified polydimethylsiloxane, single-end modified polydimethylsiloxane, and side-chain modified polydimethylsiloxane. Examples include polydimethylsiloxane modified at both ends, and polyether-modified silicone surfactants having a polyoxyethylene group or polyoxyethylene polyoxypropylene group as a modifying group are particularly preferred since they exhibit good properties as a water-based surfactant. .
Such surfactants may be appropriately synthesized or commercially available. Commercially available products are available from, for example, BIC Chemie Co., Ltd., Shin-Etsu Chemical Co., Ltd., Dow Corning Toray Silicone Co., Ltd., Nippon Emulsion Co., Ltd., Kyoeisha Chemical Co., Ltd., etc.
The above-mentioned polyether-modified silicone surfactant is not particularly limited and can be appropriately selected depending on the purpose. Examples include those introduced into the side chain of the Si part of siloxane.

(However, in the general formula (S-1), m, n, a, and b each independently represent an integer, R represents an alkylene group, and R' represents an alkyl group.)
Commercial products can be used as the polyether-modified silicone surfactant, such as KF-618, KF-642, KF-643 (Shin-Etsu Chemical Co., Ltd.), EMALEX-SS-5602, SS- 1906EX (Japan Emulsion Co., Ltd.), FZ-2105, FZ-2118, FZ-2154, FZ-2161, FZ-2162, FZ-2163, FZ-2164 (Toray Dow Corning Silicone Co., Ltd.), BYK-33, Examples include BYK-387 (BYK-Chemie Corporation), TSF4440, TSF4452, and TSF4453 (Toshiba Silicon Corporation).

As the fluorine-based surfactant, a fluorine-substituted compound having 2 to 16 carbon atoms is preferable, and a fluorine-substituted compound having 4 to 16 carbon atoms is more preferable.
Examples of the fluorosurfactant include perfluoroalkyl phosphate compounds, perfluoroalkyl ethylene oxide adducts, and polyoxyalkylene ether polymer compounds having perfluoroalkyl ether groups in their side chains. Among these, polyoxyalkylene ether polymer compounds having a perfluoroalkyl ether group in the side chain are preferred because of their low foaming properties, and in particular, fluorine-based polymer compounds represented by general formulas (F-1) and (F-2) are preferred. Surfactants are preferred.

In the compound represented by the above general formula (F-1), m is preferably an integer of 0 to 10, and n is preferably an integer of 0 to 40, in order to impart water solubility.

In the compound represented by the above general formula (F-2), Y is H, or CmF _2m+1 and m is an integer of 1 to 6, or CH ₂ CH(OH)CH ₂ -CmF _2m+1 and m is 4 to 6. An integer, or CpH _2p+1 , where p is an integer from 1 to 19. n is an integer from 1 to 6. a is an integer from 4 to 14.
Commercially available products may be used as the above-mentioned fluorosurfactant. Examples of commercially available products include Surflon S-111, S-112, S-113, S-121, S-131, S-132, S-141, and S-145 (all manufactured by Asahi Glass Co., Ltd.); Fullard FC-93, FC-95, FC-98, FC-129, FC-135, FC-170C, FC-430, FC-431 (all manufactured by Sumitomo 3M Ltd.); Megafac F-470, F -1405, F-474 (all manufactured by Dainippon Ink and Chemicals Co., Ltd.); Zonyl TBS, FSP, FSA, FSN-100, FSN, FSO-100, FSO, FS-300, UR, Capstone FS-30, FS-31, FS-3100, FS-34, FS-35 (all manufactured by Chemours); FT-110, FT-250, FT-251, FT-400S, FT-150, FT- 400SW (all manufactured by Neos Corporation), Polyfox PF-136A, PF-156A, PF-151N, PF-154, PF-159 (manufactured by Omnova Corporation), Unidyne DSN-403N (manufactured by Daikin Industries, Ltd.) Among these, Chemours' FS-3100, FS-34, FS- 300, FT-110, FT-250, FT-251, FT-400S, FT-150, FT-400SW manufactured by Neos Corporation, Polyfox PF-151N manufactured by Omnova, and Unidyne DSN- manufactured by Daikin Industries, Ltd. 403N is particularly preferred.

The content of the surfactant in the ink is not particularly limited and can be selected as appropriate depending on the purpose, but from the viewpoint of excellent wettability, ejection stability, and improved image quality, 0.001 mass % or more and 5% by mass or less, more preferably 0.05% or more and 5% by mass or less.

<Defoaming agent>
The antifoaming agent is not particularly limited and includes, for example, silicone antifoaming agents, polyether antifoaming agents, fatty acid ester antifoaming agents, and the like. These may be used alone or in combination of two or more. Among these, silicone antifoaming agents are preferred because they have excellent foam-breaking effects.

<Preservative and fungicide>
The preservative and fungicide is not particularly limited and includes, for example, 1,2-benzisothiazolin-3-one.

<Rust inhibitor>
There are no particular limitations on the rust preventive, and examples thereof include acidic sulfites, sodium thiosulfate, and the like.

<pH adjuster>
The pH adjuster is not particularly limited as long as it can adjust the pH to 7 or more, and examples thereof include amines such as diethanolamine and triethanolamine.

<Recording medium (media)>
The recording medium (media) used for recording includes, but is not particularly limited to, plain paper, glossy paper, special paper, cloth, film, OHP sheet, general-purpose printing paper, and the like.

<Processing liquid>
The treatment liquid contains a flocculant, an organic solvent, and water, and may also contain a surfactant, an antifoaming agent, a pH adjuster, a preservative, a fungicide, a rust preventive, and the like, if necessary.
For the organic solvent, surfactant, antifoaming agent, pH adjuster, preservative and antifungal agent, and rust preventive agent, the same materials as those used for ink can be used, and other materials used for known processing liquids can be used. .
The type of flocculant is not particularly limited, and examples thereof include water-soluble cationic polymers, acids, polyvalent metal salts, and the like.

<Physical properties of ink and processing liquid>
The physical properties of the ink and treatment liquid are not particularly limited and can be appropriately selected depending on the purpose. For example, the viscosity, pH, etc. are preferably within the following ranges.
The viscosity of the ink at 25°C is preferably 5 mPa·s or more and 30 mPa·s or less, and 5 mPa·s or more and 25 mPa·s or less, from the viewpoint of improving print density and character quality and obtaining good ejection properties. More preferred. Here, the viscosity can be measured using, for example, a rotational viscometer (RE-80L manufactured by Toki Sangyo Co., Ltd.). The measurement conditions are 25° C., a standard cone rotor (1°34′×R24), sample liquid volume of 1.2 mL, rotation speed of 50 rpm, and 3 minutes.
The pH of the ink and treatment liquid is preferably 7 to 12, more preferably 8 to 11, from the viewpoint of preventing corrosion of metal members in contact with the liquid.

In this embodiment, the dynamic surface tension γ(i) [mN/m] of the ink droplet when the surface life of the ink droplet is 15 ms, and the dynamic surface tension of the treatment liquid when the surface life of the treatment liquid is 15 ms. It is preferable that γ(s) [mN/m] satisfies γ(i)<γ(s).

When only ink droplets are ejected onto the media, the ink droplets tend to coalesce, especially in the media transport direction, resulting in insufficient wetting and spreading in the direction perpendicular to the media transport direction, and streaks are likely to occur. On the other hand, by using an ink droplet and a treatment liquid that satisfy γ(i)<γ(s), the ink droplet easily wets and spreads on the lyophilic pattern side formed by the treatment liquid, and the ink droplets combine. 1 can be further prevented, and the occurrence of streaks can be further suppressed.

The dynamic surface tension of the ink and treatment liquid is measured using a portable surface tension meter (manufactured by Hideko Seiki Co., Ltd., SITA DynoTester) at a temperature of 25° C. and a bubble life time of 15 msec.

It is preferable that γ(i) and γ(s) satisfy 1 [mN/m]≦γ(s)−γ(i)≦10 [mN/m]. By setting it to 1 [mN/m] or more, ink droplets are easily drawn into the processing liquid, and streaks can be further suppressed. By setting the pressure to 10 [mN/m] or less, it is possible to prevent ink droplets from being excessively drawn into the processing liquid and to further suppress streaks.

From the viewpoint of ejection properties, γ(i) preferably satisfies 25 [mN/m]≦γ(i)≦40 [mN/m]. By setting the pressure to 25 [mN/m] or more, it is possible to maintain a meniscus on the nozzle surface of the head, and it is possible to suppress the occurrence of ejection failure due to liquid overflow. By setting the pressure to 40 [mN/m] or less, ink droplets can be stably ejected without the ejection force being affected by the meniscus maintenance force.

γ(s) preferably satisfies 30 [mN/m]≦γ(s)≦45 [mN/m] from the viewpoint of desired droplet formation and ejection performance. By setting the value to 30 [mN/m] or more, when discharging the processing liquid, the tailing (ligament length) of the droplet at the time of ejection will be shortened, making it possible to make the processing liquid that lands on the target droplet. Become. For this reason, dot collapse upon landing is suppressed, making it easier to form a desired lyophilic pattern, and making it easier to draw ink droplets in a targeted direction. By setting the pressure to 45 [mN/m] or less, the generation of satellites can be suppressed and mist stains can be suppressed, so that non-discharge of the processing liquid can be suppressed.

Further, it is preferable to simultaneously satisfy 25 [mN/m]≦γ(i)≦40 [mN/m] and 30 [mN/m]≦γ(s)≦45 [mN/m]. In this case, the above effects can be further improved.

(Fourth embodiment)
Next, another embodiment of the ink ejection device according to the present invention will be described.
Description of matters similar to those in the above embodiment will be omitted.

In this embodiment, a laser irradiation method will be described as a method for forming a lyophilic pattern and a configuration of a lyophilic pattern forming means.
Examples of laser irradiation methods include a method in which the media is heated by laser irradiation, a method in which the surface of the media is modified by laser irradiation, and a method in which recesses are formed in the media by laser irradiation.

First, a method of heating the media by irradiating a laser will be explained. In this embodiment, the lyophilic pattern forming means irradiates and heats a position on the media where an ink droplet lands, and forms a non-heated area as a lyophilic pattern.

FIG. 5 shows an ink ejection device of this embodiment. In the figure, a media 51, a moving conveyance means 52, a head 53, and a laser irradiation means 54 are illustrated. Note that the laser irradiation means 54 is also referred to as a laser irradiation device.

Further, FIG. 6 is a diagram for explaining the wetting and spreading of dots when two consecutive dots are printed in the conveyance direction of the medium in this embodiment. A pixel 501, an ink droplet landing shape 502, a contour shape 503, and a heating region 504 are illustrated.

In this embodiment, laser irradiation means 54 is used as the lyophilic pattern forming means. The laser irradiation means 54 forms a locally heated area by irradiating the media with a laser. In this embodiment, the low temperature region (non-heated region) in the media can be regarded as a lyophilic pattern.

Utilizing the fact that a driving force acts on ink from a high-temperature area to a low-temperature area, the area where the ink droplets land on the media is locally heated using a laser, and the area where the ink drops are insufficiently wetted and spread is made cooler than the area where the ink lands. , which promotes wetting and spreading to the low temperature side.

Thereby, as in the above embodiment, it is possible to fill the pixel area in the media conveyance direction and the nozzle row direction, suppress streaks caused by coalescence of ink droplets, and improve image quality.

An example of this embodiment will be described below. In this embodiment, the device configuration is as shown in FIG. 5, and the laser irradiation means 54 is installed upstream of the head 53 that discharges ink in the conveyance direction of the media 51.

As the laser irradiation means 54, for example, a device commonly used in electrophotography or the like can be used. Specifically, a laser scanning optical system can be used in which a semiconductor laser is used as a laser light source and the laser beam is scanned by a polygon mirror and a scanning lens.

The laser irradiation means 54 irradiates and heats the position where the ink droplet lands with a laser before the ink droplet is ejected by the head 53 to form a heated region 504 . In this embodiment, the ink droplet landing shape 502 is an ellipse.

As a result, the temperature around the ink droplet landing position and the periphery of the pixel 501 becomes relatively lower than the heating area 504, so ink easily wets and spreads around the ink droplet landing position and the periphery of the pixel 501. A region or lyophilic pattern can be formed.

Further, a drying device placed downstream of the head typically applies a large amount of energy to heat the ink droplets after they are ejected. On the other hand, according to the present embodiment, by performing laser irradiation, the ink droplets and the media are also preheated, making it possible to reduce the energy consumption of the drying device and shorten the drying time. There is also the advantage of being able to do so.

The heating area 504 can be changed as appropriate. A heating area may be formed by irradiating all of the positions where ink droplets land with a laser, or a heating area may be formed by irradiating a part of positions where ink droplets land with a laser.

Note that the heating region 504 may selectively heat only a pixel region from which ink droplets are ejected in accordance with image data. That is, laser irradiation may be omitted for pixels from which ink droplets are not ejected. In this case, the energy used can be saved.

Next, a method of modifying the surface of the media by irradiating it with a laser will be explained.
A technique of surface-modifying media by laser irradiation is generally known, and dirt, hydrophobic groups, etc. on the surface of the laser-irradiated area are removed. In the present invention, such a surface modification technique can be used. In this embodiment, the lyophilic pattern forming means irradiates a laser around a position on the media where an ink droplet lands to modify the surface, and forms the laser irradiated area as a lyophilic pattern. Thereby, the surface-modified laser irradiation area can be regarded as a lyophilic pattern.

The method of surface-modifying the media by laser irradiation can be changed as appropriate. A method of heating by laser irradiation will also be explained while giving an example.

When heating by laser irradiation, for example, a laser in the infrared region can be used, and by heating the area irradiated with the laser, the area not irradiated with the laser becomes a relatively low temperature area, making it lyophilic. It becomes a pattern. Note that when heating is performed by laser irradiation, the heat in the laser irradiation area during media transportation may diffuse within the media before ink droplets land, making it difficult to form a lyophilic pattern as a low temperature area.

For this reason, in the case of heating by laser irradiation, it is preferable to arrange the laser irradiation means in the vicinity of the head. An example of such a configuration is shown in FIG. In FIG. 7, laser irradiation means 54a, 54b, 54c, 54d and heads 53K, 53C, 53M, 53Y are shown, and the laser irradiation means 54a, 54b, 54c, 54d are located in the vicinity of the heads 53K, 53C, 53M, 53Y. is located. In this case, since the time from laser heating to ink landing becomes shorter, it becomes easier to suppress thermal diffusion in the laser irradiated area during media conveyance.

In addition, although the conveyance speed detection device 530 and the control device 540 are illustrated in FIG. 7, the present invention is not limited to this. The control device 540 monitors the media transportation speed using the transportation speed detection device 530, and controls the ink ejection timing based on the media transportation speed.

When surface modification is performed by laser irradiation, for example, a laser in the ultraviolet region can be used. For example, a lyophilic pattern is formed by creating a functional state in which bonding hands extend at the media interface in the laser irradiation area. . When surface modification is performed by laser irradiation, there is an advantage that the surface modification effect is retained for a long time compared to a heating method.

Therefore, when a plurality of heads are arranged in an array at intervals in the media transport direction, it is sufficient to install the laser irradiation device only on the most upstream head side. In this case, even if time passes after forming the lyophilic pattern, the effect of wetting and spreading the lyophilic pattern (lyophilic effect) can be maintained. Therefore, a lyophilic effect can be easily obtained even for ink droplets ejected from the most downstream head.

FIG. 8 shows an example of a structure in which surface modification is performed by laser irradiation. In FIG. 8, the laser irradiation means 54, heads 53K, 53C, 53M, and 53Y are illustrated, and the laser irradiation means 54 is installed on the most upstream side of the head 53K in the media transport direction. Even with this arrangement, it is easy to obtain a lyophilic effect on ink droplets ejected from the most downstream head 53Y.

Note that although the conveyance speed detection device 530 and the control device 540 are illustrated in FIG. 8 as well, the present invention is not limited to this. The control device 540 monitors the media transportation speed using the transportation speed detection device 530, and controls the ink ejection timing based on the media transportation speed. Furthermore, in the case of the configuration example shown in FIG. 8, the laser irradiation means 54 and the head 53 can be arranged with a distance between them, making it easier to configure the laser irradiation means and the head as separate devices.

(Fifth embodiment)
Next, another embodiment of the ink ejection device according to the present invention will be described.
Description of matters similar to those in the above embodiment will be omitted.
In this embodiment, a method of forming recesses in a medium will be described as a method of forming a lyophilic pattern and a configuration of a lyophilic pattern forming means.

FIG. 9 shows an ink ejection device of this embodiment. In the figure, a media 601, a moving conveyance means 602, a head 603, and a lyophilic pattern forming means 607 are illustrated. Here, as in the above embodiment, an online method is used.

The lyophilic pattern forming means 607 in this embodiment includes a lifting means 604, a support member 605, and a mold 606. In this embodiment, the support member 605 is equipped with a mold 606 having fine irregularities, and the support member 605 is raised and lowered in the Z direction by the lifting means 604 to press the mold 606 against the media 601. to form a recess. The recesses formed in the media 601 can be considered as a lyophilic pattern.

The ink droplets ejected onto the media spread over the fine recesses formed in the media, so as in the above embodiment, the area of the pixels in the media conveyance direction and the nozzle row direction can be filled, and the ink droplets It is possible to suppress streaks due to coalescence and improve image quality. Further, in this embodiment, there is no need to use a processing liquid, and the cost when using a processing liquid can be reduced.

The elevating means 604 is not particularly limited, and any known configuration can be used. It is sufficient if the finely machined mold 606 can be pressed against the media and released.

The lyophilic pattern is preferably a collection of fine grooves, and the grooves preferably have a linear shape. When the lyophilic pattern is a collection of fine grooves, the ink droplet after landing can more effectively wet and spread along the fine grooves due to capillary action.

FIG. 10 shows an example where the lyophilic pattern is a collection of fine grooves.
FIG. 10 is a diagram for explaining the wetting and spreading of dots when two consecutive dots are printed in the conveyance direction of the medium in this embodiment. A pixel 61, an ink droplet landing shape 62, a contour shape 63, and a lyophilic pattern 64 are illustrated.

As shown in the figure, the lyophilic pattern is a collection of fine grooves, and the direction of the grooves (direction of the line) is parallel to the nozzle row direction. In other words, the direction of the groove is set in the direction in which the wetting is desired to spread. As a result, the landed ink droplets can quickly wet and spread in the nozzle row direction, so that the area of the pixel can be filled, and streaks caused by coalescence of the ink droplets can be suppressed.

In this embodiment, the direction of the grooves is not limited to the example shown in FIG. Any arrangement is acceptable. Further, when a lyophilic pattern is provided in a region adjacent to the landing position of an ink droplet in the media transport direction, the direction of the groove may be parallel to the media transport direction.

The lyophilic pattern can be formed by pressing a mold (also called a stamp, a plate, etc.) with unevenness onto the media as described above, or by forming notches in the media. A mold having sharp convex portions may be pressed against the media, or the grooves may be formed by forming convex portions on the media using nanoimprint technology.

When a mold having a sharp convex part capable of forming notches in the media is used as a method for forming a lyophilic pattern, the convex part of the mold 606 is made sharp by using an apparatus configuration as shown in FIG. 9, for example. By pressing the mold 606 against the media 601 using the lifting means 604 and peeling it off, a cut is formed in the media.
Note that the shape of the lyophilic pattern to be formed can be changed as appropriate, as described above, and may be, for example, line-shaped.

As a method for forming a lyophilic pattern, when forming convex portions on a medium using nanoimprint technology, it can be performed using, for example, a UV curable resin. For example, a UV curable resin is applied to the media by a resin applying means before the head ejects ink droplets, a mold having unevenness is pressed against the applied UV curable resin, and then UV is irradiated. The UV curing resin is cured. Thereby, a lyophilic pattern similar to that described above can be formed. Note that the UV curing resin is cured before the head ejects ink droplets.
Such a case is also included in the case where a recess is formed in the medium.

Note that an apparatus using such nanoimprint technology has an off-line configuration, but can be configured as shown in FIG. 12, which will be described later, for example. As a method for applying the UV curable resin to the media, for example, it can be applied by applying it with a coating roller.

In addition to the method described above, examples of the method for forming the recess include a method of forming the recess by laser irradiation.

(Sixth embodiment)
Next, an embodiment of an ink ejection system according to the present invention will be described.
Description of matters similar to those in the above embodiment will be omitted.
This embodiment is a modification of the fifth embodiment. In the fifth embodiment described above, the device configuration is an online system, but the present invention is not limited to this, and can be configured as an offline system as shown in this embodiment.

The ink ejection system of this embodiment includes an ink ejection device having a head that ejects ink droplets onto a medium, a moving conveyance device that moves the head and the medium relatively, and a moving conveyance device that causes the head to eject the ink droplets onto the medium. a lyophilic pattern forming device that forms a lyophilic pattern that wets and spreads the ink droplets around a position on the medium where the ink droplets land before ejecting; and a control device that controls ejecting the ink droplets from the head.

The ink ejection device in this embodiment does not include a lyophilic pattern forming means, and the lyophilic pattern is formed by a lyophilic pattern forming device provided separately from the ink ejection device. Further, alignment between the lyophilic pattern and the landing position of the ink droplet is performed by the control device.

The ink ejection system of this embodiment is shown in FIGS. 11 and 12. FIG. 11 is an example of an offline method compared to the example shown in FIG. 9, and the ink ejection device and the lyophilic pattern forming device (fine groove forming device) can be realized with separate devices. be. In the example shown here, alignment is performed when lyophilic pattern processing is performed offline.

In FIG. 11A, a concave portion is formed by a lyophilic pattern forming device 610 on a medium 601 conveyed by a moving conveyance means 602. In FIG. The lyophilic pattern forming device 610 is composed of an elevating means 604, a support member 605, and a mold 606, and forms a lyophilic pattern by pressing and releasing a microfabricated mold 606 onto and from media. Note that the arrow Z in the figure represents the direction in which the elevating means 604 moves up and down.

FIG. 11 shows a control device 640 and a conveyance speed detection device 630, and the control device 640 uses the conveyance speed detection device 630 to monitor the conveyance speed of the medium and determine the amount of movement of the medium. The amount of movement of the medium can be determined by a movement amount signal transmitted from the conveyance speed detection device 630, and the conveyance speed detection device 630 monitors the operation of the mobile conveyance means 602, for example. When a motor is used for the moving conveyance means 602, the number of revolutions of the motor, etc. is detected.

The control device 640 monitors the conveyance speed of the media and controls the ejection of ink droplets from the head in correspondence with the areas of the lyophilic pattern. The ink ejection timing is determined based on the conveyance speed of the medium, and the head 73 is controlled so as to eject ink droplets to match the position of the lyophilic pattern. As a result, ink droplets are ejected by the head 603 to a position corresponding to the region of the lyophilic pattern (FIG. 11(b)). According to this embodiment, even in an offline method, a lyophilic pattern can be placed in a location where ink droplets do not sufficiently spread, and streaks in merged dots can be suppressed.

The control of ink droplet ejection by the control device can be changed as appropriate. The landing timing and dot arrangement relationship may be known in advance with respect to the image data to be output, especially solid portions where streaks and unevenness are noticeable, and lyophilic pattern data may be created from the output image data. In this case, by controlling the ejection of ink droplets using the data for the lyophilic pattern, the conveyance speed of the medium, etc., the ink droplets can be ejected with higher accuracy.

Note that the control device 640 is shown schematically, and its shape, position, etc. are not limited to this example.
Further, similarly to the above embodiment, the lyophilic pattern may be formed by forming notches in the media.

Next, FIG. 12 will be explained. FIG. 12 is an example of using nanoimprint technology in an offline method. In FIG. 12A, a media 601, a movable conveyance means 602, a head 603, a coating roller 608, a UV irradiation lamp 609, a lyophilic pattern forming device 610, a conveyance speed detection device 630, and a control device 640 are illustrated. Note that descriptions of items common to those in FIG. 11 will be omitted.

In this example, a UV curable resin is applied to the media 601 by an application roller 608, which is an example of a UV curable resin application device. Next, a mold 606 having irregularities is pressed against the applied UV curable resin, and then UV irradiation is performed using a UV irradiation lamp 609, which is an example of a UV irradiation device, to cure the UV curable resin. Thereby, a lyophilic pattern similar to that of the above embodiment can be formed.

Next, after the UV curing resin is cured, the medium 601 having the lyophilic pattern is transported, and ink droplets are ejected by the head 603 (FIG. 12(b)). In this way, the UV-curable resin is cured before the head ejects ink droplets. Note that such a case is also included in forming a recess in the medium.

This embodiment is not limited to the above configuration, and can be modified as appropriate. For example, calibration may be performed. An example of calibration will be explained. First, a lyophilic pattern is formed on the media, the media is transported, and a control device recognizes the lyophilic pattern near the ejection position by the head to generate ejection timing. Next, the head ejects ink droplets based on the generated ejection timing. As the media for ejecting ink droplets, the media used to generate the ejection timing may be re-transported and the ink droplets may be ejected onto the medium, or the media used to generate the ejection timing may be A lyophilic pattern may be formed on a medium different from the medium used, and ink droplets may be ejected onto the medium.

The recognition of the lyophilic pattern by the control device can be changed as appropriate. For example, if there is a difference in color between the media and the lyophilic pattern, recognition can be performed using a camera or the like. Furthermore, if there is a difference in light absorption or reflectance between the lyophilic pattern and other areas, this can be recognized using a camera, an absorption rate detection device, a reflectance detection device, or the like.

In this way, after calibration is performed and the ejection timing is generated by the control device, ink droplets may be ejected from the head to the corresponding position. Note that the location of the lyophilic pattern formed to generate the ejection timing may or may not correspond to the image data.

(Seventh embodiment)
Next, another embodiment of the ink ejection system according to the present invention will be described.
Description of matters similar to those in the above embodiment will be omitted.
This embodiment, like the sixth embodiment, has an offline device configuration.

The present embodiment includes a marker applying device that applies a marker to the medium before the ink ejection device ejects the ink droplets, which makes it possible to detect a region of the lyophilic pattern formed on the medium; A marker detection device that detects the marker before the ejection device ejects the ink droplet is provided. Then, when the marker is detected, the control device performs control to eject the ink droplets from the head in correspondence with the area of the lyophilic pattern.

FIG. 13 shows a diagram for explaining this embodiment. 13(a) and 13(b), the media 71, moving conveyance means 72, head 73, control device 74, marker detection device 75, conveyance speed detection device 76, marker applying device 77, lyophilic pattern forming device 78 is shown. In this embodiment, as a method for forming a lyophilic pattern, an example will be described in which a lyophilic pattern is formed using a treatment liquid using a lyophilic material or the like.

It is desirable that the processing liquid be transparent or the same color as the media in order not to impair the color gamut or saturation of the image to be formed. Therefore, it may be difficult to confirm the position of the lyophilic pattern formed on the media offline.

Therefore, in this embodiment, when applying a lyophilic pattern, a marker of an arbitrary shape is applied to an arbitrary part of the media by the marker applying device 77 so that the position of the lyophilic pattern can be known, and the marker detection The position of the lyophilic pattern is determined by detecting the marker using the device.

An example of the control mechanism of the control device in this embodiment will be explained.
In FIG. 13A, a lyophilic pattern forming device 78 forms a lyophilic pattern on a medium 71 transported by a moving transport means 72, and a marker applying device 77 applies a marker to the medium. Note that the order of forming the lyophilic pattern and applying the marker is not limited to this, and can be changed as appropriate. The lyophilic pattern may be formed after the marker is applied, or at the same time.

Examples of markers include lines and crosses made with colored ink. Alternatively, the marker may be marked with transparent ink that is visible when irradiated with a black light, and the marker may be detected using the black light.

The position where the marker is applied can be changed as appropriate, and includes, for example, the edge portion of the medium. In this case, for example, the lyophilic pattern may be formed at an end portion of the media in a direction perpendicular to the media transport direction with respect to the location where the lyophilic pattern is formed. Thereby, in addition to detecting the position of the marker, by determining the conveyance speed of the media, it is possible to grasp the area where the lyophilic pattern is formed.

Next, as shown in FIG. 13(b), the media 71 is transported by the moving transport means 72, and the marker detection device 75 detects the position of the marker and the position of the lyophilic pattern. Examples of the marker detection device 75 include a camera, a reflective photosensor, and the like.

FIG. 13(b) shows a schematic diagram of the medium 71 when viewed from the marker detection device 75 side. The position where the marker is applied can be changed as appropriate as described above, for example, the end portion of the media 71 in the direction orthogonal to the media conveyance direction with respect to the location where the lyophilic pattern 701 is formed. A marker 702 can be formed in the area.

The control device 74 in this embodiment includes a storage device, and measures the distance between the marker detection device 75 and the head 73 in the media transport direction in advance and stores it in the storage device inside the control device. .

Further, the system in this embodiment includes a conveyance speed detection device 76, and the control device 74 uses the conveyance speed detection device 76 to monitor the conveyance speed of the medium and determine the amount of movement of the medium. The amount of movement of the medium is determined by the amount of movement signal transmitted from the conveyance speed detection device 76.
The conveyance speed detection device 76 monitors the operation of the mobile conveyance means 72, for example. For example, if a motor is used for the moving conveyance means 72, the number of revolutions of the motor, etc. is detected.

As an example of the control mechanism, when the media is transported and a predetermined marking is detected by the marker detection device 75, the control device 74 detects the position of the lyophilic pattern by image processing or the like. At this time, the control device 74 determines the ink ejection timing based on the distance between the marker detection device 75 and the head 73 in the media transport direction and the media movement amount signal (media transport speed), and The head 73 is controlled to eject ink droplets to match the position of the liquid pattern.

As a result, even in the offline method, ink droplets can be ejected with the lyophilic pattern placed in locations where ink droplets do not wet and spread sufficiently, and streaks in merged dots can be suppressed. Further, by using a marker, it is possible to control the landing position of the ink droplet even when the lyophilic pattern is difficult to identify, and it is possible to further improve the accuracy of the landing position of the lyophilic pattern and the ink droplet.

(Eighth embodiment)
Next, another embodiment of the ink ejection device according to the present invention will be described.
Description of matters similar to those in the above embodiment will be omitted.

In the above embodiment, the description was mainly given of a single-pass method (a method in which only the media is transported using a line head without scanning the head), but the present invention is not limited to this method. Instead, it is also applicable to a multi-pass method (a method in which printing is performed by scanning the head). That is, in the present invention, it is sufficient if the head and the medium can be relatively moved and conveyed.

Hereinafter, an example of an apparatus according to the present embodiment that uses a multi-pass method and does not perform media scanning will be described.

A diagram for explaining this embodiment is shown in FIG. FIG. 14(a) is a schematic diagram of the main parts of the ink ejection device of this embodiment, and shows the media 81, head 83, drive roller 84, belt 85, and motor 86. In the figure, arrow A indicates the scanning direction of the head 83. Here, the drive roller 84 is rotated by the motor 86, and the belt 85 is moved and conveyed, so that the head 83 is scanned.

FIG. 14(b) is a diagram schematically illustrating the shape of an ink droplet 80 when the head 83 discharges the ink droplet 80. In the figure, arrow A indicates the scanning direction of the head, and arrows shown near the ink droplet 80 are for explaining the direction of the force applied to the ink droplet 80 when vector-decomposed schematically. Ink droplets 80 ejected from the scanning head 83 may not be spherical but may have a shape as shown in the figure.

FIG. 14(c) is a diagram showing an example of the lyophilic pattern 804 in this embodiment. The ink droplet 80 ejected as shown in FIG. 14(b) lands in an elliptical shape, as shown by the ink droplet landing shape 802, and spreads.

In this embodiment, as shown in FIG. 14C, a lyophilic pattern 804 is provided in a direction perpendicular to the head scanning direction (direction A) with respect to the position where the ink droplets land. As a result, ink droplets having an elliptical shape (ink droplet landing shape 802) having an axis perpendicular to the scanning direction of the head can be wetted and spread in a direction perpendicular to the scanning direction of the head. Therefore, the occurrence of streaks between adjacent pixels 801 can be suppressed, and the outline shape 803 of the merged dot is formed so as to fill the pixels 801.

As described above, in this embodiment, the movable conveying means causes the head to reciprocate, and the lyophilic pattern forming means forms an area adjacent to a position where an ink droplet lands in a direction perpendicular to the scanning direction of the head. The lyophilic pattern is formed.

EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples.

(Preparation example of copolymer A)
Methyl ethyl ketone was placed in a reaction vessel of an automatic polymerization reactor (polymerization tester DSL-2AS type manufactured by Todoroki Sangyo Co., Ltd.) equipped with a reaction vessel equipped with a stirring device, a dropping device, a temperature sensor, and a reflux device with a nitrogen introduction device on the top. 550 g was charged and the inside of the reaction vessel was purged with nitrogen while stirring. After heating the reaction vessel to 80°C while maintaining a nitrogen atmosphere, 75.0 g of 2-hydroxyethyl methacrylate, 77.0 g of methacrylic acid, 80.0 g of styrene, and 150 g of butyl methacrylate were added using a dropping device. A mixed solution of 98.0 g of butyl acrylate, 20.0 g of methyl methacrylate, and 40.0 g of "Perbutyl (registered trademark) O" (manufactured by NOF Corporation) was added dropwise over 4 hours. After completion of the dropwise addition, the reaction was further continued at the same temperature for 15 hours to obtain an anionic group-containing styrene-acrylic copolymer A having an acid value of 100, a weight average molecular weight of 21,000, and a glass transition temperature Tg (calculated value) of 31°C. A methyl ethyl ketone solution was obtained. After the reaction was completed, part of the methyl ethyl ketone was distilled off under reduced pressure to adjust the nonvolatile content to 50%. Thereby, a [copolymer A] solution was obtained.

(Preparation example 1 of pigment dispersion)
In a mixing tank equipped with a cooling jacket, 1,000 g of carbon black (trade name: Raven 1080, manufactured by Columbian Carbon Japan Co., Ltd.), 800 g of [Copolymer A] solution, 143 g of 10% aqueous sodium hydroxide solution, 100 g of methyl ethyl ketone and 1,957 g of water were charged and mixed with stirring. The mixed liquid was passed through a dispersion device (SC Mill SC100, manufactured by Mitsui Mining Co., Ltd.) filled with zirconia beads with a diameter of 0.3 mm, and was heated for 6 hours using a circulation method (a method in which the dispersion liquid discharged from the dispersion device was returned to the mixing tank). Dispersed. The rotational speed of the dispersion device was 2,700 rpm, and cold water was passed through the cooling jacket to maintain the dispersion temperature at 40° C. or lower.
After the dispersion was completed, the stock dispersion solution was extracted from the mixing tank, and then the mixing tank and the flow path of the dispersion device were washed with 10,000 g of water, and the mixture was combined with the stock dispersion solution to obtain a diluted dispersion liquid. The diluted dispersion was placed in a glass distillation apparatus, and the entire amount of methyl ethyl ketone and a portion of the water were distilled off. After cooling to room temperature, 10% hydrochloric acid was added dropwise with stirring to adjust the pH to 4.5, and the solid content was filtered with a Nutsche filter (manufactured by Nippon Kagaku Kikai Seizo Co., Ltd., pressure filter) and washed with water. . Take the cake in a container, add 200g of 20% potassium hydroxide aqueous solution, disperse with a disper (TK Homo Disper, manufactured by Tokushu Kika Kogyo Co., Ltd.), and then add water to adjust the nonvolatile content. [Pigment dispersion 1] was obtained in which 20% by mass of carbon black was dispersed in an aqueous medium as composite particles coated with a carboxyl group-containing styrene-acrylic copolymer neutralized in potassium hydroxide.

(Ink preparation example 1)
3-ethyl-3-hydroxymethyloxetane 5% by weight, 1,2-propanediol 20% by weight, glycerin 10% by weight, 2-ethyl-1,3-hexanediol 2.0% by weight, polyether-modified siloxane 1. 5% by mass and ion-exchanged water were stirred for 1 hour and mixed uniformly, and 7% by mass of rosin-modified maleic acid resin (Harima Kasei Co., Ltd., Harimac R-100) was added and stirred for another 1 hour until uniformly mixed. After mixing, [Pigment Dispersion 1] was added so that the solid content was 5% by mass, and the mixture was further stirred for 1 hour to mix uniformly. The resulting mixed solution was filtered under pressure using a polyvinylidene fluoride membrane filter having an average pore size of 0.8 μm to remove coarse particles and dust, thereby obtaining [Ink 1].

(Ink Preparation Examples 2 to 5, Treatment Liquids 1 to 6 Preparation Examples 2 to 10)
Inks 2 to 5 and treatment liquids 1 to 6 were obtained in the same manner as in Ink Preparation Example 1, except that the compositions and contents were changed to those shown in Tables 1 and 2.
In addition, the unit of each number of composition in Table 1 and Table 2 is "mass %."

(Measurement of dynamic surface tension)
The dynamic surface tension of each ink and each treatment liquid was measured using a portable surface tension meter (manufactured by Hideko Seiki Co., Ltd., SITA DynoTester) at a temperature of 25° C. and a bubble life time of 15 msec.
Note that in Tables 1 and 2, "15 ms dynamic surface tension" represents the dynamic surface tension when the surface life is 15 ms.

The detailed contents of each component in Tables 1 and 2 are as follows.
・Rosin-modified maleic acid resin (product name: Harimak R-100, manufactured by Harima Kasei Co., Ltd.)
・Polyether modified siloxane (product name: TEGO Wet-270, Evonik)
・Surfynol (Product name: Surfynol 440, Nissin Chemical Industry Co., Ltd.)
・Unidyne DSN-403N (Daikin Industries)

(Examples 1 to 10)
Next, the above inks 1 to 5 and the above treatment liquids 1 to 6 were combined as shown in Table 3 below, and the streaks and ink ejection stability were evaluated according to the following methods and evaluation criteria.

<Streak>
Printed samples were obtained using the ink ejection apparatus shown in FIG. 1, in which the lyophilic pattern forming means was configured as an inkjet treatment liquid applying apparatus. Inkjet glossy paper was used as the media, and a 3 cm square gradation image formed by a dot pattern with varying gradations was used as the print chart.
Next, a 3 cm square gradation image formed by a dot pattern with varying gradations was visually observed, and streaks were evaluated based on the following evaluation criteria. An evaluation of "○" or "△" was evaluated as being practically possible.

[Evaluation criteria]
〇: No streaks are observed. △: Some streaks are seen, but there is no problem. (The streaks cannot be identified unless they are checked from a distance of 10 cm or less from the paper surface.)
×: Streaks are clearly visible with the naked eye (streaks can be discerned even when visually checked from a distance of 30 cm or more from the paper surface)

<Ink ejection stability>
In the ink ejection apparatus shown in FIG. 1, an apparatus was used in which the lyophilic pattern forming means was configured as an inkjet type treatment liquid applying apparatus. Fill the head of the processing liquid application device with the processing liquid, leave it in a decap state for 3 days in an environment of 23°C and 50% humidity, and print one solid image on inkjet glossy paper based on the evaluation criteria below. The presence or absence of streaks, white spots, and jetting disturbances in the solid image area was visually evaluated. Since the treatment liquid is colorless, it is confirmed by adding 0.1% FB 0.005% aqueous solution to stain it. “〇” and “△” were considered as passing ranks. For "x", when observing the nozzles after discharge, many nozzles were found to be clogged with precipitates.

[Evaluation criteria]
○: No streaks, white spots, or jetting irregularities are observed in the solid area.
△: Some streaks, white spots, and jetting irregularities are observed in solid areas.
×: Streaks, white spots, and jetting irregularities are seen on half of the solid prints or on the front.

11 Media 12 Moving conveyance means 13 Head 14 Lyophilic pattern forming means 21a, 21b Pixels 22a, 22b Ink droplet landing shape 23a, 23b Contour shape 31a, 31b Pixel 32a, 32b Ink droplet landing shape 33a, 33b Outline shape 34a, 34b , 35a Lyophilic pattern 41 Head 42 Pixel 43 Ink droplet landing shape 44a, 44b, 44c Lyophilic pattern 45 Outline shape 51 Media 52 Moving conveyance means 53, 53K, 53C, 53M, 53Y Head 54, 54a to 54d Laser irradiation Means 501 Pixel 502 Ink droplet landing shape 503 Contour shape 504 Heating area 530 Conveying speed detection device 540 Control device 61 Pixel 62 Ink droplet landing shape 63 Outline shape 64 Lyophilic pattern 601 Media 602 Moving conveyance means 603 Head 604 Lifting means 605 Support Member 606 Mold 607 Lyophilic pattern forming means 608 Application roller 609 UV irradiation lamp 610 Lyophilic pattern forming device 630 Conveyance speed detection device 640 Control device 71 Media 72 Moving conveyance means 73 Head 74 Control device 75 Marker detection device 76 Conveyance speed Detection device 77 Marker applying device 78 Lyophilic pattern forming device 81 Media 82 Motor 83 Head 84 Drive roller 85 Belt 801 Pixel 802 Ink droplet landing shape 803 Outline shape 804 Lyophilic pattern

Japanese Patent Application Publication No. 2006-326984 Japanese Patent Application Publication No. 2006-276509 Japanese Patent Application Publication No. 2017-065098

Claims (16)

a head that ejects ink droplets onto the media;
a moving conveyance means for relatively moving the head and the medium;
lyophilic pattern forming means for forming a lyophilic pattern that wets and spreads the ink droplets around a position on the medium where the ink droplets land before the head ejects the ink droplets onto the medium; Prepare,
The lyophilic pattern is formed by a treatment liquid that has an affinity with the ink droplets ,
The dynamic surface tension γ(i) [mN/m] of the ink droplet when the surface life of the ink droplet is 15 ms, and the dynamic surface tension γ of the treatment liquid when the surface life of the treatment liquid is 15 ms. (s) [mN/m] satisfies γ(i)<γ(s) . The ink according to claim 1 , wherein the γ(i) and the γ(s) satisfy 1 [mN/m]≦γ(s)−γ(i)≦10 [mN/m]. Discharge device. The ink ejection device according to claim 1 or 2 , wherein the γ(i) satisfies 25 [mN/m]≦γ(i)≦40 [mN/m]. The ink ejection device according to claim 1 , wherein the γ(s) satisfies 30 [mN/m] ≦ γ(s)≦45 [mN/m]. a head that ejects ink droplets onto the media;
a moving conveyance means for relatively moving the head and the medium;
lyophilic pattern forming means for forming a lyophilic pattern that wets and spreads the ink droplets around a position on the medium where the ink droplets land before the head ejects the ink droplets onto the medium; Prepare,
The ink ejection apparatus is characterized in that the lyophilic pattern forming means forms the lyophilic pattern by forming recesses in the medium. The recess is a line-shaped groove,
The ink ejection device according to claim 5 , wherein the lyophilic pattern is formed of a plurality of the grooves. The lyophilic pattern forming means does not form the lyophilic pattern at a position where the ink droplet lands, but forms the lyophilic pattern at a position where the landed ink droplet can come into contact with the ink droplet when it wets and spreads. The ink ejection device according to any one of claims 1 to 6 , characterized in that : The moving conveyance means conveys the medium,
Claims 1 to 7 , wherein the lyophilic pattern forming means forms the lyophilic pattern in a region adjacent to a position where the ink droplet lands in a direction perpendicular to the conveying direction of the medium. The ink ejection device according to any one of the above. The moving conveyance means causes the head to reciprocate,
9. The lyophilic pattern forming means forms the lyophilic pattern in a region adjacent to a position where the ink droplet lands in a direction perpendicular to the scanning direction of the head. The ink ejection device according to any one of the above. The lyophilic pattern forming means forms the lyophilic pattern around the position where the ink droplets land only when the ejection conditions are such that the ink droplets land on adjacent pixels, respectively. The ink ejection device according to any one of claims 1 to 9 . The ink ejecting apparatus according to any one of claims 1 to 10 , wherein the lyophilic pattern forming means forms the lyophilic pattern in a region spanning boundaries between adjacent pixels. an ink ejection device having a head that ejects ink droplets onto media;
a moving conveyance device that relatively moves the head and the medium;
a lyophilic pattern forming device that forms a lyophilic pattern that wets and spreads the ink droplets around a position on the medium where the ink droplets land before the head ejects the ink droplets onto the medium;
a control device that controls ejecting the ink droplets from the head in accordance with the area of the lyophilic pattern;
The lyophilic pattern is formed by a treatment liquid that has an affinity with the ink droplets ,
The dynamic surface tension γ(i) [mN/m] of the ink droplet when the surface life of the ink droplet is 15 ms, and the dynamic surface tension γ of the treatment liquid when the surface life of the treatment liquid is 15 ms. (s) [mN/m] satisfies γ(i)<γ(s) . an ink ejection device having a head that ejects ink droplets onto media;
a moving conveyance device that relatively moves the head and the medium;
a lyophilic pattern forming device that forms a lyophilic pattern that wets and spreads the ink droplets around a position on the medium where the ink droplets land before the head ejects the ink droplets onto the medium;
a control device that controls ejecting the ink droplets from the head in accordance with the area of the lyophilic pattern;
The lyophilic pattern forming device is an ink ejection system characterized in that the lyophilic pattern forming device forms the lyophilic pattern by forming recesses in the medium. a marker applying device that applies a marker that makes it possible to detect a region of the lyophilic pattern formed on the medium to the medium before the ink ejecting device ejects the ink droplet;
a marker detection device that detects the marker before the ink ejection device ejects the ink droplet,
14. The control device controls ejecting the ink droplets from the head in correspondence with the area of the lyophilic pattern when the marker is detected. Ink ejection system. an ink droplet ejection step in which the head ejects ink droplets onto the media;
a moving conveyance step of relatively moving the head and the medium;
a lyophilic pattern forming step of forming a lyophilic pattern that wets and spreads the ink droplets around a position on the medium where the ink droplets land before the head discharges the ink droplets onto the medium; including,
The lyophilic pattern forming step includes forming the lyophilic pattern using a treatment liquid that has an affinity with the ink droplets .
The dynamic surface tension γ(i) [mN/m] of the ink droplet when the surface life of the ink droplet is 15 ms, and the dynamic surface tension γ of the treatment liquid when the surface life of the treatment liquid is 15 ms. (s) [mN/m] satisfies γ(i)<γ(s) . an ink droplet ejection step in which the head ejects ink droplets onto the media;
a moving conveyance step of relatively moving the head and the medium;
a lyophilic pattern forming step of forming a lyophilic pattern that wets and spreads the ink droplets around a position on the medium where the ink droplets land before the head discharges the ink droplets onto the medium; including,
The ink ejection method is characterized in that the lyophilic pattern forming step forms the lyophilic pattern by forming recesses in the medium.

Images