Liquid discharge device

Abstract

To provide a liquid discharge device capable of preventing the occurrence of an image defect on an ink layer serving as a substrate and improving fastness of an image against washing and friction.SOLUTION: This liquid discharge device comprises: an image forming unit that includes a head for discharging ink to a matter to be printed and scans the matter; a conveyance unit; and a control unit. A conveying directing of the matter to be printed is a first direction, and a direction orthogonal to the first direction is a second direction. A substrate is formed on the matter to be printed, and then an image is formed on the substrate. The substrate includes first and second ink layers. During the first conveyance of the matter to be printed, the first ink layer is formed by discharging ink at the landing position of a dot pitch continuous in the first and second directions to form a dot. During the second conveyance of the matter to be printed, the second ink layer is formed by discharging ink at a landing position shifted by a half-pitch from the ink landing position for forming the first ink layer in the first and second directions to form a dot.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a liquid ejection device.

Background Art

[0002] Conventionally, an image forming apparatus such as an inkjet printer that includes a head for ejecting a recording liquid such as ink and performs inkjet recording is known.

[0003] In such an image forming apparatus, for example, an apparatus that ejects ink onto a dark-colored (e.g., black) T-shirt by serial operation using an inkjet recording head to form an image is known. In this case, white ink is ejected onto the T-shirt in the first conveyance to form a base, and color ink is ejected in the second conveyance to form an image. Thereafter, heating or pressurization is performed as necessary to fix the ink, and the process of image formation is completed.

[0004] Patent Document 1 discloses a configuration in which, for the purpose of obtaining a sufficient matte image, dots of the upper layer are overprinted on and between the dots of the lower layer with a higher resolution than the lower layer image.

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the conventional technology, when forming an ink layer with the first white ink, there are often many places where the base of the T-shirt can be seen, such as small dots called black spots. In this case, the ink may peel off starting from the black spots, and the fastness of the image against washing and friction may decrease. Further, in the conventional technology, when there are places where the base of the image can be seen, it is difficult to cover the base and prevent the occurrence of image defects.

[0006] Therefore, an object of the present invention is to provide a liquid ejection device that prevents image defects from occurring in the base and improves the fastness of the image against washing and friction.

Means for Solving the Problems

[0007] In order to solve the above problems, the liquid ejection device of the present invention includes a liquid ejection head that ejects ink onto a printing target, an image forming unit that scans, and a conveyance unit that conveys the printing target, a control unit, and is a liquid ejection device comprising: assuming the conveyance direction of the printing target as a first direction and the direction orthogonal to the first direction as a second direction, the control unit performs control to eject ink while scanning the image forming unit while conveying the printing target in a minute amount, and performs control to form an image on the printing target after forming an underlayer on the printing target, the underlayer is composed of a first ink layer and a second ink layer, in the first conveyance of the printing target, the first ink layer is formed by ejecting ink at landing positions with a continuous dot pitch with respect to the first direction and the second direction to form dots, in the second conveyance of the printing target, the second ink layer is formed by ejecting ink at landing positions shifted by a half pitch with respect to the landing positions of the ink in the first direction and the second direction when forming the first ink layer to form dots which is characterized in that.

Advantages of the Invention

[0008] According to the present invention, it is possible to provide a liquid ejection device that prevents image defects from occurring in the underlayer and improves the fastness of the image against washing and friction.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Mode for Carrying Out the Invention

[0010] Hereinafter, the liquid ejection device according to the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments shown below, and can be changed within the scope that those skilled in the art can conceive, such as other embodiments, additions, modifications, deletions, etc., and as long as the functions and effects of the present invention are achieved in any aspect, it is included in the scope of the present invention.

[0011] (First Embodiment) The liquid ejection device of the present embodiment includes a liquid ejection head that ejects ink onto a printing target, an image forming unit that scans, and a conveyance unit that conveys the printing target, and a control unit, and is a liquid ejection device comprising: The conveyance direction of the printing target is defined as a first direction, and a direction orthogonal to the first direction is defined as a second direction. The control unit performs control to eject ink while scanning the image forming unit while conveying the printing target in a minute amount, and performs control to form an image on the base after forming a base on the printing target. The base is composed of a first ink layer and a second ink layer. In the first conveyance of the printing target, a first ink layer is formed by ejecting ink at landing positions with a continuous dot pitch in the first direction and the second direction to form dots. In the second conveyance of the printing target, a second ink layer is formed by ejecting ink at landing positions shifted by a half pitch with respect to the landing positions of the ink in the first direction and the second direction when forming the first ink layer to form dots. It is characterized by the above.

[0012] In a printer that prints on T-shirts, when printing on a colored T-shirt, it is common practice to form a white base with white ink and then overlay and print a color image. When forming the white base, ink droplet landing misalignment may occur, or the size of the ink droplets may decrease due to environmental changes, resulting in a smaller dot diameter. In this case, there may be a portion where the base of the T-shirt is visible. Such a portion where the object to be printed is exposed is sometimes also referred to as a black spot. Black spots are caused by a gap occurring between ink droplets due to ink droplet landing misalignment or the like. Since black spots are image defects, a high-quality image cannot be obtained when black spots occur.

[0013] In this embodiment, the base is formed by forming a first ink layer in the first conveyance and a second ink layer in the second conveyance. Further, the second ink layer is obtained by discharging ink at a position shifted by half a pitch with respect to the landing position of the first ink layer to form dots. As a result, dots are formed at locations where image defects (black spots) may occur, and the black spots can be covered to prevent image defects. According to this embodiment, in addition to the first ink layer, by overlapping and printing dots with a half-pitch shift to form the second ink layer, even when the dots of the first ink layer are misaligned or the dots become smaller and the base of the object to be printed becomes visible, that base can be covered.

[0014] The liquid ejection device may also be referred to as an image forming device, a printing device, a printing apparatus, an inkjet recording device, an inkjet device, or the like.

[0015] FIG. 1 is a schematic side view of the liquid ejection device of this embodiment. FIG. 1 may also be a schematic cross-sectional view. The liquid ejection device 1 includes a head 11 that ejects ink onto an object to be printed, a carriage 10 that scans, a table 17 that conveys the object to be printed, and a control unit 22. The head 11 is an example of a liquid ejection head. The carriage 10 is an example of an image forming unit. The table 17 is an example of a conveyance unit.

[0016] The liquid ejection device 1 has a guide rod 12 supported by a frame 15. The carriage 10 is attached so as to pass through the guide rod 12. The carriage 10 has a head 11 that ejects ink. The head 11 may also be referred to as a liquid ejection head, a recording head, etc., and can be used as an inkjet head, an inkjet recording head, etc.

[0017] The carriage 10 reciprocates, for example, between the front side and the back side of the paper surface. The object to be printed 20 is placed on the upper surface of the table 17 and conveyed. The arrow in the figure indicates the moving direction of the table 17 and schematically shows the conveying direction of the object to be printed. The control unit 22 controls, for example, the table 17 and the carriage 10. The control unit 22 performs control to eject ink while scanning the carriage 10 while conveying the object to be printed 20 in a minute amount, and also performs control to form an underlayer on the object to be printed 20 and then form an image on the underlayer. For example, the object to be printed is conveyed as the table 17 is conveyed by a certain amount, and ink is ejected from the head 11 onto the object to be printed 20 while the carriage 10 scans. In this way, the carriage scanning and the minute conveyance are repeated to form an image on the object to be printed.

[0018] As shown by the arrow in the figure, the table 17 can move not only in one direction but also in two directions or multiple directions. For example, after conveying one object to be printed 20 once, it is possible to return to the printing start position and perform a second conveyance on that object to be printed 20. For example, the conveyance of the object to be printed 20 from the printing start position to the printing end position is regarded as one conveyance. The printing start position and the printing end position are not particularly limited and can be selected as appropriate.

[0019] Figure 2 is a schematic plan view showing a general dot arrangement when white ink is ejected by the liquid ejection device. It is a figure showing a part of a normal underlayer.

[0020] In the figure, the first direction is the conveyance direction of the object to be printed, and the second direction is a direction orthogonal to the first direction (conveyance direction). The second direction is also the reciprocating scanning direction of the carriage 10. The first direction may be referred to as the vertical direction, and the second direction may be referred to as the horizontal direction. The vertical direction may simply be referred to as "vertical", and the horizontal direction may simply be referred to as "horizontal".

[0021] The dashed lines in the figure represent the resolution in the vertical direction and the resolution in the horizontal direction. The resolution in the vertical direction may be referred to as the vertical resolution, and is also denoted as the vertical resolution Rv. The resolution in the horizontal direction may be referred to as the horizontal resolution, and is also denoted as the horizontal resolution Rh. Generally, ink is ejected at the pitch of the vertical resolution Rv and the vertical resolution Rh, and dots are formed when the ink lands on the object to be printed. In the figure, ink is ejected at the intersection of the dashed line in the vertical direction and the dashed line in the horizontal direction.

[0022] As shown in the figure, a normal base is one in which dots are formed at the resolution in the first direction and the resolution in the second direction, and is an ink layer formed at the dot pitch of the vertical resolution Rv and the vertical resolution Rh. In the normal base, ink is ejected at the landing positions with a continuous dot pitch in the first direction and the second direction, and dots are formed. The normal base does not need to be formed over the entire surface of the object to be printed, and the area to be formed can be selected according to the ink layer that becomes an image.

[0023] The size of the dots can be appropriately selected. For example, by making it larger than dot pitch × 2 1 / 2 a part of adjacent dots can overlap. By having a part of adjacent dots overlap, the object to be printed serving as the base can be completely covered.

[0024] Figure 3 is a plan schematic view showing the dot arrangement when a black spot, which is an image defect, occurs. The first direction, the second direction, the resolution, etc. are the same as in Figure 2. The example shown in Figure 3 represents the case where a part of the arranged dots becomes smaller due to some factor. Note that as the factor for the dots becoming smaller, for example, a change in the environment can be cited as described above.

[0025] In the figure, it is represented by reference numeral 30a to distinguish the dots that have become smaller. In the illustrated example, both the dots of reference numeral 30 and the dots of reference numeral 30a are formed of white ink.

[0026] If the dot diameter becomes as small as about the dot pitch, as shown in the figure, gaps are generated around the smaller dots 30a, and portions where the base layer becomes visible occur. In this case, a high-quality image cannot be obtained. The portions where the base layer becomes visible are also referred to as black spots, image defects, and the like.

[0027] On the other hand, in the present embodiment, the base layer is formed by transporting the printing target 20 twice, and the base layer is composed of a first ink layer and a second ink layer. In the first transport of the printing target, the first ink layer is formed by discharging ink at landing positions with a continuous dot pitch in the first direction and the second direction to form dots. In the second transport of the printing target, the second ink layer is formed by discharging ink at landing positions shifted by half a pitch with respect to the landing positions of the ink in the first direction and the second direction when forming the first ink layer to form dots. By forming the base layer in this way, the occurrence of black spots (image defects) in the base layer can be prevented, and the fastness against washing and friction can be improved. According to the present embodiment, it is possible to suppress the ink from peeling off starting from black spots.

[0028] In the present embodiment, an image is formed on the base layer formed as described above. To distinguish it from the base layer, the image may be referred to as a third ink layer or the like. In the present embodiment, in the second transport of the printing target or the transport of the printing target after the third time, ink is discharged onto the base layer to form an image (third ink layer). According to the present embodiment, an image excellent in fastness against washing and friction can be obtained.

[0029] When forming an image (the third ink layer) during the second conveyance of the object to be printed, the second ink layer and the third ink layer are formed during the second conveyance of the object to be printed. To do this, although not particularly limited, for example, a head that discharges the ink for forming the second ink layer and a head that discharges the ink for forming the third ink layer are arranged side by side. In this case, immediately after the dots for forming the second ink layer are printed and the base is completed, the dots for forming the third ink layer can be printed to form an image. In this case, since the base and the image can be formed in two conveyances, productivity is improved.

[0030] The ink for forming the base can be appropriately selected. It is preferable to form the first ink layer and the second ink layer with the same ink. In this case, the components of the base can be unified.

[0031] For example, the first ink layer and the second ink layer are formed with white ink. When forming an image on a colored object to be printed, the image quality can also be improved by using white ink to form the base.

[0032] The third ink layer that becomes the image is formed with, for example, color ink. The color ink is not particularly limited, and for example, one or more selected from black, cyan, magenta, and yellow inks can be used. Also, an ink such as white ink may be used.

[0033] The object to be printed is not particularly limited and can be appropriately selected. Examples include paper, recording paper, printing paper, film, cloth, etc. The object to be printed is preferably cloth such as a T-shirt. For example, when using this embodiment for cloth such as a T-shirt, a base with suppressed black spots can be obtained, and a printed matter with improved image fastness against washing, friction, etc. can be obtained. The object to be printed may also be referred to as a recording medium, medium, media, etc.

[0034] Figure 4 is a schematic plan view showing the dot arrangement of the base layer in Example 1 of the present embodiment. Fig. 4(A) shows the dot arrangement of the first ink layer formed by the first conveyance, and Fig. 4(B) is a diagram for explaining the dots of the second ink layer formed by the second conveyance.

[0035] For the sake of explanation, in the figure, the dots formed by the first conveyance are represented by reference numeral 31, and the dots formed by the second conveyance are represented by reference numeral 32. Example 1 is an example of forming a base layer with white ink. Therefore, dots 31 and 32 are formed with white ink.

[0036] The base layer in Example 1 is formed by conveying the object to be printed twice. As shown in Fig. 4(A), in the first conveyance, ink is ejected at the landing positions with a continuous dot pitch with respect to the first direction and the second direction to form dots 31. Thereby, the first ink layer is formed. As shown in Fig. 4(B), in the second conveyance, ink is ejected at the landing positions shifted by half a pitch with respect to the landing positions of the ink in the first direction and the second direction when forming the first ink layer to form dots 32. Thereby, the second ink layer is formed.

[0037] The first ink layer in Example 1 may be referred to as a normal base layer or the like. In a normal base layer, ink is ejected at the pitches of the resolution in the first direction and the resolution in the second direction and lands on the object to be printed to form dots. It can also be said that a normal base layer is formed by ejecting ink at the landing positions with a continuous dot pitch with respect to the first direction and the second direction to form dots. In Example 1, it can also be said that a normal base layer is formed in the first conveyance, and in the second conveyance, ink is ejected at positions shifted by half of the resolution in the first direction and shifted by half of the resolution in the second direction to form dots, thereby additionally forming a normal base layer. According to Example 1, it is possible to prevent black spots (image defects) in the base layer.

[0038] In the first embodiment, similar to the matters described with reference to FIG. 2, the size of the dots can be appropriately selected. For example, by making the size of dot 31 larger than dot pitch × 2 1 / 2 a part of adjacent dots can overlap. By overlapping a part of adjacent dots, it becomes easier to cover the substrate to be printed.

[0039] To shift the dot pitch in the second conveyance by half with respect to the dot pitch in the first conveyance, for example, the following is done. When conveying the substrate to be printed for the first time, the control unit adjusts the conveyance of the table 17, reduces the conveyance distance when conveying intermittently, and shifts by half a pitch in the vertical direction (the first direction) so that ink is ejected. Further, the control unit adjusts the ejection timing of the head 11 and shifts by half a pitch in the horizontal direction (the second direction) so that ink is ejected.

[0040] In the figure, the types of the broken lines are changed to display the landing positions of the dots 31 formed in the first conveyance and the landing positions of the dots 32 formed in the second conveyance. The dots 32 formed in the second conveyance are formed at positions shifted by Rv / 2 and Rh / 2 with respect to the dots 31 formed in the first conveyance.

[0041] The droplet volume of the ink droplets ejected in the second conveyance, that is, the droplet volume of the ink droplets for forming the second ink layer, can be appropriately selected. The size of the dots 32 formed in the second conveyance is preferably equal to or smaller than the size of the dots 31 formed in the first cycle. In this case, the ink amount of the added second ink layer can be suppressed, and it is possible to prevent the ink amount on the substrate from becoming excessive. By preventing the ink amount from becoming excessive, it is possible to suppress an increase in the ink amount remaining on the surface of the substrate to be printed and prevent deterioration of the fastness. Also, by preventing the ink amount from becoming excessive, the ink cost can be suppressed.

[0042] The sizes of dot 31 and dot 32 can be compared, for example, by observing the size of dot 31 after the first conveyance of the object to be printed is completed and observing the size of dot 32 after the second conveyance of the object to be printed is completed. The sizes of dot 31 and dot 32 may also be observed and compared after the second conveyance of the object to be printed is completed. As a method for adjusting the sizes of dot 31 and dot 32, a method of adjusting the droplet volume of the ejected ink droplets can be mentioned.

[0043] A third ink layer serving as an image is formed on the substrate thus obtained. As described above, the third ink layer serving as an image may be formed in the second conveyance or may be formed in the third and subsequent conveyances. When forming in the second conveyance, the second ink layer and the third ink layer are formed in one conveyance. When forming an image in the third and subsequent conveyances, it is preferable to form the image in the third conveyance, but it is not limited thereto, and the image may be formed in a conveyance other than the third conveyance, or the image may be formed in a plurality of conveyances after the third conveyance.

[0044] In the present embodiment, the formation of the substrate and the formation of the image are separately described according to the number of conveyances of the object to be printed, but instead of the conveyance of the object to be printed, it may be described using the term "cycle". A cycle means that the formation of the ink layer is completed by repeating carriage scanning and minute conveyance of the object to be printed so as to fill dots at a predetermined resolution. In one cycle, while intermittently conveying the object to be printed by a minute amount from, for example, the printing start position, carriage scanning is performed to eject ink, and it is conveyed to the printing end position to form an ink layer. In the present embodiment, the first ink layer is formed in the first cycle, and dots are formed at positions shifted by half of the dot pitch in the vertical and horizontal directions in the second cycle to form the second ink layer. Also, the third ink layer serving as an image is formed in the second cycle or the third and subsequent cycles.

[0045] (Second Embodiment) Next, another embodiment of the present invention will be described. Descriptions of matters similar to those in the above embodiment will be omitted.

[0046] The liquid ejection device of the present embodiment includes a liquid ejection head that ejects ink onto a printing object, an image forming unit that scans, and a conveyance unit that conveys the printing object, and a control unit, and is a liquid ejection device comprising: Taking the conveyance direction of the printing object as the first direction and the direction orthogonal to the first direction as the second direction, the control unit performs control to eject ink while scanning the image forming unit while conveying the printing object in a minute amount, and performs control to form an image on the base layer after forming the base layer on the printing object. The base layer is composed of a first ink layer and a second ink layer. In the first conveyance of the printing object, the first ink layer is formed by ejecting ink at landing positions every other pitch of a continuous dot pitch in the first direction and the second direction to form dots. In the second conveyance of the printing object, the second ink layer is formed by ejecting ink at landing positions shifted by one pitch with respect to the landing positions of the ink in the first direction or the second direction when forming the first ink layer to form dots. It is characterized by this.

[0047] In the present embodiment, when forming the base layer, the dots usually formed in one time are halved and formed in two conveyances. In the first conveyance, the ink is landed at every other pitch vertically and horizontally to form dots, and in the second conveyance, dots are formed at the thinned positions. Thereby, black spots (image defects) in the base layer can be prevented. Further, in the present embodiment, the amount of ink used can be suppressed. Further, in the present embodiment, the amount of ink penetrating into the printing object is suppressed and the ink remaining on the surface increases, so that the image density becomes higher and a higher-quality image can be obtained.

[0048] FIG. 5 is a schematic plan view showing the dot arrangement of the base layer in Example 2 of the present embodiment. FIG. 5(A) is the dot arrangement of the first ink layer formed in the first conveyance, and FIG. 5(B) is the dot arrangement of the ink formed in the second conveyance.

[0049] For the sake of explanation, in the figure, the dots formed in the first conveyance are represented by reference numeral 31, and the dots formed in the second conveyance are represented by reference numeral 32. In the second embodiment, an example of forming the first ink layer with white ink is shown. Therefore, the dots 31 and 32 are formed with white ink.

[0050] In the first conveyance shown in FIG. 5(A), the regularly arranged dots 31 are thinned out every other pitch. That is, ink is ejected and dots are formed at the landing positions every other pitch of the continuous dot pitch with respect to the first direction and the second direction. FIG. 5(A) can also be said to be ejecting ink and forming dots with thinning out every other pitch with respect to the first direction and the second direction on a normal base. Thereby, the first ink layer is formed.

[0051] In the second conveyance shown in FIG. 5(B), dots are formed at the locations thinned out in the first conveyance. In the first ink layer, since dots are formed with thinning out every pitch, in the second conveyance, ink is ejected and dots are formed at the landing positions shifted by one pitch with respect to the landing positions of the ink in the first direction or the second direction when forming the first ink layer. By forming the second ink layer in this way, dots can be formed at the locations thinned out in the first ink layer, and a base without image defects can be formed.

[0052] In FIG. 5(B), the landing positions of the dots 32 forming the second ink layer are positions shifted by one pitch with respect to the landing positions of the ink in the first direction or the second direction with respect to the landing positions of the dots 31 forming the first ink layer. It may be in the first direction or the second direction. By doing so, dots can be formed as the second ink layer at the locations thinned out in the first ink layer, and a base without image defects can be formed.

[0053] In Example 2, it is preferable that the size of dot 32 of the second ink layer formed by the second conveyance is equal to or larger than the size of dot 31 of the first ink layer formed by the first conveyance. By doing so, image defects can be further suppressed.

[0054] As described above, the matters described in the above embodiment are also applicable to this embodiment. For example, in this embodiment as well, it is preferable to form the first ink layer and the second ink layer with the same ink. For example, it is preferable to form the first ink layer and the second ink layer with white ink. Further, this embodiment can also be suitably applied to cloth such as a T-shirt.

[0055] Aspects of the present invention are as follows, for example. <1> A liquid ejection apparatus including a liquid ejection head that ejects ink onto a printing target, an image forming unit that scans, a conveyance unit that conveys the printing target, and a control unit, the liquid ejection apparatus comprising: wherein the conveyance direction of the printing target is a first direction, a direction orthogonal to the first direction is a second direction, the control unit performs control to eject ink while scanning the image forming unit while conveying the printing target in a minute amount, and performs control to form an image on the base after forming a base on the printing target, the base includes a first ink layer and a second ink layer, in the first conveyance of the printing target, the first ink layer is formed by ejecting ink at landing positions with a continuous dot pitch in the first direction and the second direction to form dots, in the second conveyance of the printing target, the second ink layer is formed by ejecting ink at landing positions shifted by a half pitch with respect to the landing positions of the ink in the first direction and the second direction when forming the first ink layer to form dots characterized liquid ejection apparatus. <2> The size of the dots in the second ink layer is equal to or smaller than the size of the dots in the first ink layer. The liquid ejection device according to <1>, characterized in that. <3> A liquid ejection device including a liquid ejection head that ejects ink onto a printing target, a scanning image forming unit, a conveyance unit that conveys the printing target, and a control unit, wherein the conveyance direction of the printing target is defined as a first direction, and a direction orthogonal to the first direction is defined as a second direction, the control unit performs control to eject ink while scanning the image forming unit while conveying the printing target in a minute amount, and performs control to form an image on the printing target after forming an underlayer on the printing target, the underlayer is composed of a first ink layer and a second ink layer, in the first conveyance of the printing target, the first ink layer is formed by ejecting ink at landing positions every other pitch of a continuous dot pitch in the first direction and the second direction to form dots, in the second conveyance of the printing target, the second ink layer is formed by ejecting ink at landing positions shifted by one pitch with respect to the landing positions of the ink in the first direction or the second direction when forming the first ink layer to form dots The liquid ejection device characterized by the above. <4> The size of the dots in the second ink layer is equal to or larger than the size of the dots in the first ink layer. The liquid ejection device according to <3>, characterized in that. <5> In the second conveyance of the printing target or the conveyance of the printing target three or more times later, the control unit ejects ink onto the underlayer to form the image. The liquid ejection device according to any one of <1> to <4>, characterized in that. <6> The first ink layer and the second ink layer are formed of the same ink. The liquid ejection device according to any one of <1> to <5>, characterized in that. <7> The first ink layer and the second ink layer are formed of white ink. The liquid discharge device according to <6>, characterized in that. <8> The object to be printed is cloth. The liquid discharge device according to any one of <1> to <7>, characterized in that.

Explanation of Signs

[0056] 1 Liquid discharge device 10 Carriage 11 Head 12 Guide rod 13 Exterior 15 Main body frame 16 Lifting mechanism 17 Table 18 Ink 20 Object to be printed 22 Control unit 23 Tank 24 Support member 25 Sensor 30, 31, 32 Dots

Prior Art Documents

Patent Documents

[0057]

Patent Document 1

Claims

1. A liquid ejection device including a liquid ejection head that ejects ink onto a printing medium, a scanning image forming unit, a conveyance unit that conveys the printing medium, and a control unit, wherein the conveyance direction of the printing medium is defined as a first direction, and a direction orthogonal to the first direction is defined as a second direction, the control unit performs control to eject ink while scanning the image forming unit while conveying the printing medium in a minute amount, and performs control to form an image on the printing medium after forming a base on the printing medium, the base is composed of a first ink layer and a second ink layer, in the first conveyance of the printing medium, a first ink layer is formed by ejecting ink at landing positions with a continuous dot pitch with respect to the first direction and the second direction to form dots, in the second conveyance of the printing medium, a second ink layer is formed by ejecting ink at landing positions shifted by a half pitch with respect to the landing positions of the ink in the first direction and the second direction when forming the first ink layer to form dots A liquid ejection device characterized by the above.

2. The size of the dots in the second ink layer is equal to or smaller than the size of the dots in the first ink layer The liquid ejection device according to claim 1, characterized by the above.

3. A liquid ejection device including a liquid ejection head that ejects ink onto a printing medium, a scanning image forming unit, a conveyance unit that conveys the printing medium, and a control unit, wherein the conveyance direction of the printing medium is defined as a first direction, and a direction orthogonal to the first direction is defined as a second direction, the control unit performs control to eject ink while scanning the image forming unit while conveying the printing medium in a minute amount, and performs control to form an image on the printing medium after forming a base on the printing medium, the base is composed of a first ink layer and a second ink layer, in the first conveyance of the printing medium, a first ink layer is formed by ejecting ink at landing positions every other pitch with a continuous dot pitch with respect to the first direction and the second direction to form dots, in the second conveyance of the printing medium, a second ink layer is formed by ejecting ink at landing positions shifted by one pitch with respect to the landing positions of the ink in the first direction or the second direction when forming the first ink layer to form dots A liquid ejection device characterized by the above.

4. The size of the dots in the second ink layer is equal to or larger than the size of the dots in the first ink layer The liquid ejection device according to claim 3, characterized in that...

5. In the conveyance of the second printed material or the conveyance of the printed material after the third time, the control unit ejects ink onto the base to form the image. The liquid ejection device according to claim 1 or 3, characterized in that...

6. The first ink layer and the second ink layer are formed of the same ink. The liquid ejection device according to claim 1 or 3, characterized in that...

7. The first ink layer and the second ink layer are formed of white ink. The liquid ejection device according to claim 6, characterized in that...

8. The printed material is cloth. The liquid ejection device according to claim 1 or 3, characterized in that...

Images