Inkjet Printing Device

Abstract

To provide a head unit configured so that a position of an inkjet head can be adjusted easily and accurately, and provide an inkjet printing device.SOLUTION: The head unit comprises first-sixth heads 11-16 in which a plurality of nozzles that discharge liquid to a printing sheet P are arranged in a predetermined direction, where the first-sixth heads 11-16 are arranged side by side in a direction orthogonal to an arranging direction of the nozzles along a relative conveying direction of the printing sheet P and are arranged to be shifted in the arranging direction of the nozzles so that the nozzle of either of the first and the sixth heads 11 and 16 and the nozzles of some of the second-fourth heads 12-14 are positioned at the same position with respect to the arranging direction of the nozzles.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a head unit having a plurality of ejection portions that eject liquid, and to an inkjet printing device including the head unit. [Background technology]

[0002] 2. Description of the Related Art Inkjet printing devices have been proposed that perform printing by ejecting ink from an inkjet head onto a print medium such as paper or film.

[0003] As an inkjet printing device, for example, an inkjet printing device has been proposed in which a head unit having multiple inkjet heads is moved in the main scanning direction to print in a predetermined main scanning range, and the head unit is moved relatively to the printing medium in a sub-scanning direction perpendicular to the main scanning direction to sequentially print the main scanning range.

[0004] As a head unit used in such an inkjet printing device, a head unit has been proposed in which a plurality of inkjet heads are arranged so as to be shifted in the sub-scanning direction and different liquids are ejected from each inkjet head (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2020-185737 A Summary of the Invention [Problem to be solved by the invention]

[0006] Here, when printing is performed using a head unit as described above, there are cases where the pretreatment liquid is ejected from one of the inkjet heads arranged to be shifted in the sub-scanning direction, and the color ink is ejected from the other inkjet head.

[0007] In such a case, first, the pretreatment liquid is applied to a predetermined main scanning range by one of the inkjet heads, and then the head unit is moved in the sub-scanning direction relative to the print medium, whereby the inkjet heads that eject color inks are positioned on the main scanning range on which the pretreatment liquid has been applied, and the color inks are ejected onto the pretreatment liquid.

[0008] Therefore, since the main scanning range of the pretreatment liquid and the main scanning range of the color inks need to be matched simply by moving the head unit relatively in the sub-scanning direction, the inkjet head that ejects the pretreatment liquid and the inkjet head that ejects the color inks need to be adjusted to a preset positional relationship.

[0009] When adjusting the position of such an inkjet head, for example, it is conceivable to use the print results from the inkjet head. However, some of the pretreatment liquids described above are transparent and cannot be seen with the naked eye, and for inkjet heads that eject pretreatment liquids, it is not possible to adjust the position of the inkjet head by checking the print results as in the case of color inkjet heads.

[0010] An object of the present invention is to provide a head unit and an inkjet printing apparatus that enable easy and accurate adjustment of the position of an inkjet head. [Means for solving the problem]

[0011] The head unit of the present invention has a plurality of ejection sections in which a plurality of nozzles that eject liquid are arranged in a predetermined direction, and among the plurality of ejection sections, a first ejection section and a second ejection section that eject different liquids are arranged side by side in a direction perpendicular to the nozzle arrangement direction along the relative transport direction of the printing medium with respect to the plurality of ejection sections, and are arranged offset in the nozzle arrangement direction so that some of the nozzles of the first ejection section and some of the nozzles of the second ejection section are in the same position in the nozzle arrangement direction. Effect of the Invention

[0012] According to the head unit of the present invention, the first and second ejection sections are arranged offset in the nozzle arrangement direction so that some of the nozzles of the first ejection section and some of the nozzles of the second ejection section are at the same position in the nozzle arrangement direction, so that the position of the inkjet head can be adjusted easily and accurately. Note that a method for adjusting the position of the inkjet head using such a configuration will be described in detail later. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a diagram showing a schematic configuration of an inkjet printing device using an embodiment of a head unit of the present invention; [Diagram 2] A view of the inkjet printing device shown in Figure 1 from the direction of arrow A. [Diagram 3] FIG. 2 is a top view showing a schematic configuration of an example of a head unit; [Figure 4] FIG. 2 is a block diagram showing the configuration of a control system of the inkjet printing apparatus shown in FIG. [Diagram 5] FIG. 13 is a diagram showing an example of a print result when the sixth head is accurately positioned relative to the third head; [Figure 6] FIG. 13 is a diagram showing an example of a print result when the sixth head is arranged one line closer to the third head in the front-to-rear direction; [Figure 7] FIG. 13 is a diagram showing an example of a print result when the sixth head is disposed one line or more away from the third head in the front-to-back direction; [Figure 8] FIG. 13 is a diagram showing an example of a position adjustment pin as a sixth head position adjustment mechanism. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] An inkjet printing device using an embodiment of a head unit of the present invention will be described in detail below with reference to the drawings. The inkjet printing device of this embodiment is characterized by the configuration of the head unit, but first, the configuration of the entire inkjet printing device will be described. Fig. 1 is a schematic diagram of an inkjet printing device 1 of this embodiment. Fig. 2 is a view of the inkjet printing device 1 shown in Fig. 1 as seen from the direction of arrow A. In the following description of the embodiment, the up, down, left, right, front, back, and rear indicated by arrows in Fig. 1 are defined as the up, down, left, right, front, and rear directions of the inkjet printing device 1.

[0015] As shown in FIG. 1, the inkjet printing apparatus 1 of this embodiment includes a base 2, a foot stand 3, a platen 4, a rail portion 5, and a head unit 10.

[0016] The bases 2 are columnar members extending in the front-rear direction and arranged in parallel with a gap in the left-right direction. Two wheels 2a are provided on the bottom surface of each of the two bases 2.

[0017] A foot stand 3 is provided upright on each base 2. A platen 4 is supported on the upper surfaces of the two foot stands 3 facing each other.

[0018] An arc-shaped front paper guide 4a and a rear paper guide 4b extend from the front and rear of the platen 4. Also, as shown in Fig. 2, a vacuum chamber 4c in which a fan 4d is installed is provided below the platen 4. Note that the vacuum chamber 4c is not shown in Fig. 1.

[0019] When the fan 4d in the vacuum chamber 4c rotates, a negative pressure is created inside the vacuum chamber 4c, and a suction force is generated in the suction holes (not shown) formed in the platen 4. The printing paper P is attracted to the platen 4 by the suction force generated in the suction holes of the platen 4.

[0020] 2, a drive roller 6 and a pressure roller 7 are provided behind the platen 4 so as to face each other. Note that the drive roller 6 and the pressure roller 7 are omitted from FIG.

[0021] The drive roller 6 is an elongated roller extending in the extension direction of the platen 4, and is rotated by a transport drive motor 61 (see FIG. 4) which will be described later.

[0022] The pressure roller 7, like the drive roller 6, is an elongated roller extending in the extension direction of the platen 4, and is supported by a lifting mechanism (not shown) so as to be movable up and down.

[0023] Then, the printing paper P on the rear paper guide 4b is clamped between the drive roller 6 and the pressure roller 7, and as the drive roller 6 rotates with the printing paper P pressed by the pressure roller 7, the printing paper P is sent forward.

[0024] Provided on the front side of the base 2 of the inkjet printing device 1 is a take-up side core holding section 8 that detachably holds a core 8a that takes up the printing paper P. The take-up side core holding section 8 is linked to a take-up drive motor 81 (see FIG. 4) via a torque limiter (not shown), and is configured so that the take-up side core holding section 8 is rotated by the take-up drive motor 81.

[0025] Further, a supply-side core holding section 9 is provided on the rear side of the base 2 of the inkjet printing device 1, which detachably holds a core 9a of roll paper on which printing paper P is wound in a roll shape. The supply-side core holding section 9 is linked to a supply drive motor 91 (see FIG. 4) via a torque limiter (not shown), and is configured so that the supply-side core holding section 9 is rotated by the supply drive motor 91.

[0026] As shown in Figure 2, the roll paper (printing paper P) held by the supply side core holding section 9 is pulled out and passed through the rear paper guide 4b, between the drive roller 6 and the pressure roller 7, over the platen 4, and the front paper guide 4a, before being wound onto the core 8a held by the winding side core holding section 8.

[0027] A rail section 5 is installed via a support member (not shown) on the upper part of the two legs 3. The rail section 5 includes a rail (not shown) extending in the left-right direction and a main scanning drive motor 51 (see FIG. 4) that moves the head unit 10 back and forth in the left-right direction on the rail.

[0028] Next, the head unit 10 of this embodiment will be described.

[0029] As shown in Fig. 3, the head unit 10 of this embodiment includes six heads, a first head 11 to a sixth head 16. The second head 12, the third head 13, the fourth head 14, and the fifth head 15 are inkjet heads that eject ink of different colors. In this embodiment, as shown in Fig. 3, the second head 12 ejects Y (yellow) ink, the third head 13 ejects K (black) ink, the fourth head 14 ejects M (magenta) ink, and the fifth head 15 ejects C (cyan) ink.

[0030] The sixth head 16 has a similar configuration to the second to fifth heads 12 to 15, but ejects a pretreatment liquid instead of ink. The pretreatment liquid is a liquid that is applied for pretreatment before ink is ejected onto the printing paper P to perform printing processing. As the pretreatment liquid, for example, a liquid for improving the color development and uniform application of the ink is used, but a pretreatment liquid that is already known can be used.

[0031] The first head 11 is an inkjet head that ejects ink in the same manner as the second to fifth heads 12 to 15. For example, when printing a pattern on a black base, the first head 11 ejects white ink onto the black base so that the black color of the base does not show through.

[0032] As shown in FIG. 3, the first to sixth heads 11 to 16 are arranged in a line in the moving direction (left-right direction) of the head unit 10. However, the first head 11 and the second to fifth heads 12 to 15 are arranged in a staggered manner, and the sixth head 1 6 The second to fifth heads 12 to 15 are also arranged in a staggered manner.

[0033] That is, the second to fifth heads 12 to 15 and the first and sixth heads 11, 16 are disposed at different positions in a direction (front-to-back direction) perpendicular to the movement direction of the head unit 10. The first head 11 and the sixth head 16 are disposed at the same position in a direction (front-to-back direction) perpendicular to the movement direction of the head unit 10. The second to fifth heads 12 to 15 are also disposed at the same position in a direction (front-to-back direction) perpendicular to the movement direction of the head unit 10.

[0034] The first to sixth heads 11 to 16 are held by a head holder 10a, and the first to sixth heads 11 to 16 are installed so that their ejection surfaces are exposed from the head holder 10a.

[0035] The first to sixth heads 11 to 16 have a plurality of nozzles (indicated by circles in FIG. 3) that eject liquid such as ink or pretreatment liquid onto the printing paper P. The plurality of nozzles of the first to sixth heads 11 to 16 are arranged in the front-rear direction. In this embodiment, the front-rear direction is the direction in which the nozzles are arranged, and is also the transport direction of the printing paper P.

[0036] The first and sixth heads 11, 16 and the second to fifth heads 12 to 15 are arranged to be offset in the front-to-rear direction (the direction in which the nozzles are arranged) as described above, but some of the nozzles of the first head 11 and some of the nozzles of the second to fifth heads 12 to 15 are arranged to be in the same position in the front-to-rear direction. 6 A part of the nozzles in the first head 10 and a part of the nozzles in the second to fifth heads 12 to 15 are arranged so as to be in the same position in the front-rear direction.

[0037] In this embodiment, as shown in FIG. 3, the first head 11 and the second to fifth heads head The sixth head 12 to 15 are arranged so that each head is located at the same position in the front-rear direction by one nozzle. 6 and the second to fifth head 12 to 15 are arranged so that they are at the same position in the front-rear direction by the amount of one nozzle.

[0038] Here, when the first to sixth heads 11 to 16 are arranged in a staggered manner as in this embodiment, for example, the first and sixth heads 11, 16 and the second to fifth heads 12 to 15 need to scan the same scanning range, so it is necessary to accurately adjust their positional relationship. In this embodiment, the first and sixth heads 11, 16 and the second to fifth heads 12 to 15 are arranged to be in the same position in the front-to-back direction by one nozzle as described above, so that the above-mentioned positional relationship can be easily and accurately adjusted. Note that a method for adjusting the positional relationship between the first and sixth heads 11, 16 and the second to fifth heads 12 to 15 will be described in detail later.

[0039] 4 is a block diagram showing the configuration of a control system of the inkjet printing apparatus 1 of this embodiment. The inkjet printing apparatus 1 operates each of the controlled parts shown in FIG.

[0040] The print control device 17 and the inkjet printing device 1 are connected by a communication line such as a LAN (Local Area Network) or an Internet line, and are configured to be able to communicate with each other. The communication line may be wired or wireless.

[0041] The print control device 17 is composed of a computer equipped with a CPU (Central Processing Unit), a semiconductor memory, a hard disk, etc. The print control device 17 executes a print control program stored in advance in a storage medium such as a semiconductor memory or a hard disk based on an input print job, etc., and controls each part shown in FIG. 4 by operating an electric circuit.

[0042] Next, a printing operation of the inkjet printing apparatus 1 of this embodiment will be described. Note that, here, a case will be described in which the first head 11 is not used, and the pretreatment liquid is ejected from the sixth head 16 to apply it to the printing paper P, and then ink is ejected from the second to fifth heads 12 to 15 to print on the printing paper P to which the pretreatment liquid has been applied.

[0043] First, as shown in Figure 2, a roll of paper is placed on the supply side core holding section 9, and the roll of paper (printing paper P) is pulled out and passed through the rear paper guide 4b, between the drive roller 6 and the pressure roller 7, over the platen 4, and the front paper guide 4a, before being wound around the core 8a held by the take-up side core holding section 8.

[0044] Then, the printing control device 17 feeds out the printing paper P by rotating the supply side core holding unit 9, the winding side core holding unit 8, and the drive roller 6, and temporarily stops the feeding of the printing paper P when it reaches the initial printing position.

[0045] Next, the print control device 17 operates the main scanning drive motor 51 to move the head unit 10 in a first direction (either left or right direction) on the rail portion 5. Then, the print control device 17 controls the first position of the head unit 10 along with the movement of the head unit 10. 6 Head 16 is operated to apply the pretreatment liquid to the first scan line. Note that, when the first scan line is initially scanned, ink is not ejected from the second to fifth heads 12 to 15.

[0046] Next, the print control device 17 advances the print paper P by one scan line so that the first scan line, to which the pretreatment liquid is applied, is positioned directly below the second to fifth heads 12-15.

[0047] Then, the print control device 17 moves the head unit 10 on the rail portion 5 in a second direction opposite to the first direction, and, with the movement, ejects ink from the second to fifth heads 12 to 15 to print the first scan line. Furthermore, while printing the first scan line, the print control device 17 also operates the sixth head 16 to apply the pretreatment liquid to a second scan line that is next to the first scan line.

[0048] Next, the print control device 17 feeds out the printing paper P by one scan line, and places a second scan line directly below the second to fifth heads 12 to 15, and places a third scan line immediately below the sixth head 16.

[0049] Then, the print control device 17 moves the head unit 10 in the first direction on the rail portion 5, and in conjunction with the movement, operates the second to fifth heads 12 to 15 and the sixth head 16 to apply pretreatment liquid to the third scan line and print on the second scan line.

[0050] Thereafter, the print control device 17 alternately repeats the process of feeding out one scan line of printing paper P and moving the head unit 10 on the rail portion 5 in the first direction or the second direction, in the same manner as described above, to sequentially apply pretreatment liquid to the (n+1)th scan line and print on the nth scan line.

[0051] In the above description, the operation is described when the pretreatment liquid is applied by the sixth head 16 without using the first head 11, but the base may be printed using the first head 11 without using the sixth head 16. In this case, the ink ejection timing from the first head 11 is the same as the ejection timing from the sixth head 16 described above.

[0052] Next, the position adjustment of the first to sixth heads 11 to 16 performed before the above-mentioned printing operation will be described. Note that in this embodiment, the second to fifth heads 12 to 15 are arranged at the same position in the front-to-rear direction, and a method of adjusting the position of the sixth head 16 relative to the positions of the second to fifth heads 12 to 15 will be described. Also, in this embodiment, the third head 13 and the sixth head 16 correspond to the first ejection section and the second ejection section in the present invention.

[0053] As described above, the sixth head 16 ejects the pretreatment liquid, but depending on the type of pretreatment liquid, it may not be visible even after printing. Therefore, it is very difficult to adjust the position of the sixth head 16 using only the application result of the pretreatment liquid.

[0054] Therefore, in this embodiment, in one scan of the head unit 10 in the first direction or the second direction, the pretreatment liquid is ejected from the sixth head 16, and the K ink is ejected from the third head 13.

[0055] In this embodiment, as described above, the third head 13 (the second to fifth heads 12 to 15) and the sixth head 16 are disposed so as to be in the same position in the front-to-rear direction by one nozzle. Therefore, when the third head 13 (the second to fifth heads 12 to 15) and the sixth head 16 are disposed accurately, both the pretreatment liquid and the K ink are ejected to the same dot on one line in the same position in the front-to-rear direction by one scan of the head unit 10.

[0056] In this way, when both the pretreatment liquid and the K ink are ejected onto the same dot in one scan of the head unit 10, the K ink is ejected onto the dot of the pretreatment liquid before the pretreatment liquid dries, so the K ink spreads due to the pretreatment liquid, and the shape of the dot changes compared to when the K ink is ejected onto a location where the pretreatment liquid is not ejected. For example, the size and non-uniformity (degree of circularity) of the dot change.

[0057] Specifically, when the sixth head 16 is accurately positioned with respect to the third head 13 (the second to fifth heads 12 to 15) as shown in Fig. 3, that is, when both the pretreatment liquid and the K ink are ejected only onto dots on one line, the K dots on the line onto which the pretreatment liquid is ejected are deformed due to bleeding, as shown in Fig. 5. In contrast, the K dots formed by the nozzles of the third head 13 that are not positioned at the same positions in the front-to-back direction as the nozzles of the sixth head 16 do not suffer from bleeding due to the pretreatment liquid, and therefore remain nearly perfectly circular.

[0058] Therefore, when the print result is as shown in FIG. 5, it can be determined that the sixth head 16 is positioned accurately relative to the third head 13 (the second to fifth heads 12 to 15), and there is no need to adjust the position of the sixth head 16.

[0059] On the other hand, for example, as shown in Figure 6, if the K dots deformed by bleeding cover two lines, it can be determined that the sixth head 16 is positioned one line closer to the third head 13 (the second to fifth heads 12 to 15) in the front-to-back direction.

[0060] Therefore, in the case of a print result such as that shown in FIG. 6, the sixth head 16 is moved by one line in the direction away from the third head 13 to adjust its position.

[0061] Also, for example, as shown in Figure 7, if there are no K dots deformed by bleeding, it can be determined that the sixth head 16 is positioned one line or more away from the third head 13 (the second to fifth heads 12 to 15) in the front-to-back direction.

[0062] Therefore, when the print result is as shown in FIG. 7, the sixth head 16 is moved a predetermined distance in the direction in which the sixth head 16 approaches the third head 13, the head unit 10 is scanned once again, and both the pretreatment liquid and the K ink are ejected. The print result is confirmed, and the position of the sixth head 16 is adjusted as appropriate.

[0063] During actual printing, the pretreatment liquid ejection range (scanning range) by the sixth head 16 and the ink ejection range (scanning range) by the second to fifth heads 12 to 15 overlap by one nozzle in one scan, but the ink ejection by the second to fifth heads 12 to 15 is not necessarily continuous for one line, but is thinned out, so the bleeding described above does not become a problem. Furthermore, during actual printing, it is also possible not to eject pretreatment liquid or ink in the overlapping range of one nozzle between the sixth head 16 and the second to fifth heads 12 to 15 in one scan.

[0064] For adjusting the position of the sixth head 16, a position adjustment pin 16a may be provided at the end of the sixth head 16, as shown in FIG. 8. The position adjustment pin 16a is formed in a cylindrical shape and extends in the vertical direction. The rotation axis of the position adjustment pin 16a is eccentric in the length direction (front-rear direction) of the sixth head 16. This allows the position of the sixth head 16 in the front-rear direction to be adjusted by rotating the position adjustment pin 16a in the direction of the arrow shown in FIG. 8. Note that the position adjustment mechanism for the sixth head 16 is not limited to the above-mentioned position adjustment pin 16a, and other known mechanisms may be used.

[0065] Furthermore, in the above embodiment, a method for adjusting the position of the sixth head 16 that ejects invisible pretreatment liquid has been described, but when an invisible liquid is also ejected from the first head 11, similarly to the sixth head 16, the position can be adjusted by ejecting both the liquid from the first head 11 and the K ink from the third head 13 in one scan and checking the print result of the K ink (degree of bleeding). For example, in the above embodiment, an example has been described in which white ink is ejected from the first head 11 onto a black background, but when white ink is ejected from the first head 11 onto a white background, the white ink is invisible, so the above-mentioned position adjustment method can be used.

[0066] Furthermore, in the above embodiment, an example has been described in which the pretreatment liquid is ejected from the sixth head 16, but the invisible transparent liquid is not limited to the pretreatment liquid, and may be an overcoat ink or the like.

[0067] According to the inkjet printing device 1 of the above embodiment, some of the nozzles of the first and sixth heads 11, 16 and some of the nozzles of the second to fifth heads 12-15 are arranged to be in the same position in the front-to-rear direction. Therefore, for example, as described above, by ejecting both ink and pretreatment liquid onto the same dot by the third head 13 and the sixth head 16 in a single scan and checking the printing result, it is possible to easily and accurately adjust the position of the sixth head 16 relative to the second to fifth heads 12-15.

[0068] Furthermore, in the above embodiment, the third head 13 ejects visible K ink, and the sixth head 16 ejects invisible pretreatment liquid. Therefore, even with the sixth head 16 ejecting invisible pretreatment liquid, position adjustment can be performed easily and accurately.

[0069] Furthermore, in the above embodiment, the third head 13 (the second to fifth heads 12 to 15) and the sixth head 16 are arranged to be in the same position by one nozzle in the front-to-back direction, so that the overlapping area between the nozzles of the third head 13 and the nozzles of the sixth head 16 in the front-to-back direction can be minimized.

[0070] Here, the greater the overlapping portion between the nozzles of the third head 13 and the nozzles of the sixth head 16 in the front-to-rear direction, the greater the effect of the pretreatment liquid ejected from the sixth head 16 on the ink ejected from the third head 13. That is, the pretreatment liquid ejected from the sixth head 16 may mix with the ink ejected from the third head 13 and solidify on the ink ejection surface of the third head 13, which may result in poor ink ejection.

[0071] As described above, by minimizing the overlapping portion between the nozzles of the third head 13 and the nozzles of the sixth head 16 in the front-rear direction (by one nozzle), it is possible to prevent the occurrence of the above-mentioned ink ejection defects. However, in the present invention, the overlapping portion in the front-rear direction is not limited to one nozzle, and may be, for example, two nozzles. The extent to which the overlapping portion should be increased may be appropriately determined depending on the left-right distance between the second to fifth heads 12 to 15 that eject ink and the sixth head 16 that ejects the pretreatment liquid.

[0072] Furthermore, in the above embodiment, the position of the sixth head 16 in the front-rear direction is adjustable by the position adjustment pin 16a, so that the position of the sixth head 16 can be easily adjusted.

[0073] Furthermore, in the above embodiment, the head unit 10 is configured to be movable in the left-right direction, so that by checking the print result of the line printed in one scan, it is possible to more accurately recognize the degree of bleeding of the K dots as described above, and to perform more accurate position adjustment.

[0074] The present invention further discloses the following supplementary notes. (Additional Note)

[0075] In the head unit of the present invention, one of the first ejection section and the second ejection section can eject visible ink, and the other ejection section can eject invisible liquid.

[0076] In the head unit of the present invention, the first ejection section and the second ejection section can be disposed so as to be at the same position in the nozzle arrangement direction by one nozzle.

[0077] In the head unit of the present invention, at least one of the first ejection section and the second ejection section is preferably configured so that the position in the nozzle arrangement direction is adjustable.

[0078] The head unit of the present invention can be configured to be movable in a direction perpendicular to the nozzle arrangement direction.

[0079] An inkjet printing device of the present invention includes the above-described head unit, and performs printing by ejecting ink from the ejection portion of the head unit onto a printing medium. [Explanation of symbols]

[0080] 1 Inkjet printing device 2 Base 2a wheels 3 pedestal 4 Platen 4a Front paper guide 4b Rear paper guide 4c Vacuum chamber 4d fan 5 Rail section 6 Drive roller 7 Pressure roller 8. Winding side core holder 8a Core body 9 Supply side core holding part 9a Core body 10 Head Unit 10a Head holder 11~16 Heads 1~6 17 Printing control device 16a Position adjustment pin 51 Main scanning drive motor 61 Transport drive motor 81 Winding drive motor 91 Supply drive motor P printing paper

Claims

1. a head unit including a plurality of ejection sections in which a plurality of nozzles for ejecting liquid are arranged in a predetermined direction, and among the plurality of ejection sections, a first ejection section for ejecting ink and a second ejection section for ejecting a pretreatment liquid are arranged side by side in a direction perpendicular to the nozzle arrangement direction along a relative transport direction of a print medium with respect to the plurality of ejection sections, and the head unit is arranged with a shift in the nozzle arrangement direction so that some nozzles of the first ejection section and some nozzles of the second ejection section overlap in the nozzle arrangement direction; a control unit that controls the head unit to eject ink from the first ejection unit and eject a pretreatment liquid from the second ejection unit while moving the head unit in a direction perpendicular to the transport direction, and to eject the ink onto the same dot before the pretreatment liquid ejected onto the print medium dries, thereby causing bleeding in the dot; An inkjet printing device, wherein the first ejection section and the second ejection section are arranged so as to overlap with each other by only one nozzle in a nozzle arrangement direction.

2. a head unit including a plurality of ejection sections in which a plurality of nozzles for ejecting liquid are arranged in a predetermined direction, and among the plurality of ejection sections, a first ejection section for ejecting ink and a second ejection section for ejecting a pretreatment liquid are arranged side by side in a direction perpendicular to the nozzle arrangement direction along a relative transport direction of a print medium with respect to the plurality of ejection sections, and the head unit is arranged with a shift in the nozzle arrangement direction so that some nozzles of the first ejection section and some nozzles of the second ejection section overlap in the nozzle arrangement direction; a control unit that controls the head unit to eject ink from the first ejection unit and eject a pretreatment liquid from the second ejection unit while moving the head unit in a direction perpendicular to the transport direction, and to eject the ink onto the same dot before the pretreatment liquid ejected onto the print medium dries, thereby causing bleeding in the dot; An inkjet printing apparatus, wherein at least one of the first ejection section and the second ejection section is configured to be able to adjust a position in a nozzle arrangement direction.

3. 3. The inkjet printing apparatus according to claim 1, wherein the first ejection section ejects visible ink, and the second ejection section ejects invisible pretreatment liquid.

Images