Ink-jet printer

Abstract

To prevent a head gap between an ink-jet head and a medium partially having a different thickness from being varied, in an ink-jet printer.SOLUTION: An ink-jet printer 1 comprises: a plurality of pressing rollers 21 for energizing a medium M1 (kraft bag) onto an ink-jet head 11 side; and a plurality of butting rollers 31 for abutting the medium M1 energized by the plurality of pressing rollers 21 to form a head gap G between the medium M1 and an ink-jet head 11, that are arranged at positions opposed to the plurality of pressing rollers 21. The pressing rollers 21 located on one side (front side) of the ink-jet head 11 in a width direction D2 of the medium M1, that is orthogonal to a conveyance direction D1 of the medium M1, and the pressing rollers 21 located on the other side of the ink-jet head 11 in the width direction D2 independently energize the medium M1 onto the ink-jet head 11 side.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to inkjet printing devices. [Background technology]

[0002] Conventionally, in order to properly maintain the head gap between the inkjet head and the paper, a conveying device has been proposed that is equipped with a pair of intermediate rollers that are positioned upstream or downstream of the inkjet head in the paper conveying direction and rotate following a conveying belt (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2015-006952 A Summary of the Invention [Problem to be solved by the invention]

[0004] For example, a kraft bag has a partially different thickness due to the folded-back portion of the end of the bag and the paper string attached to the bag. Also, a cardboard box before being made into a box may have a partially different thickness due to pasting of the ends together. When a medium having a partially different thickness like this is printed by ejecting ink from an inkjet head, the head gap differs depending on the part. In particular, when the thickness of the medium differs partially in the width direction perpendicular to the conveying direction of the medium, the variation in the head gap cannot be suppressed by the intermediate roller pair arranged on the upstream side or downstream side of the inkjet head as described above.

[0005] Furthermore, if the head gap is set to match the thin portion of the medium, the head gap will be narrow in the partially thick portion of the medium, increasing the risk of collision between the medium and the inkjet head, whereas if the head gap is set to match the thick portion of the medium, the head gap will be wide in the partially thin portion of the medium, causing a large amount of mist to scatter and image degradation.

[0006] An object of the present invention is to provide an inkjet printing apparatus capable of suppressing fluctuations in the head gap between an inkjet head and a medium having a thickness that varies partially. [Means for solving the problem]

[0007] In one aspect, an inkjet printing device includes an inkjet head that ejects ink onto a medium, a plurality of pressure rollers that urge the medium toward the inkjet head, and a plurality of abutment rollers that are positioned opposite the plurality of pressure rollers and against which the medium urged by the plurality of pressure rollers urges the medium, thereby forming a head gap between the medium and the inkjet head, the plurality of pressure rollers and the plurality of abutment rollers including the pressure roller and the abutment roller located on one side of the inkjet head in a width direction of the medium perpendicular to a transport direction of the medium, and the pressure roller and the abutment roller located on the other side of the inkjet head in the width direction, and the pressure roller located on one side of the inkjet head in the width direction and the pressure roller located on the other side of the inkjet head in the width direction each independently urge the medium toward the inkjet head. Effect of the Invention

[0008] According to this aspect, it is possible to suppress fluctuations in the head gap between the inkjet head and a medium having a thickness that varies partially. [Brief description of the drawings]

[0009] [Figure 1] 1 is a front view showing an inkjet printing apparatus according to an embodiment; [Diagram 2] FIG. 4 is a perspective view showing a bottom surface of a head holder in the embodiment. [Diagram 3] 1 is a left side view showing a medium having a thickness that varies partially across the width direction, a pressing roller, an abutment roller, and the like in an embodiment; [Figure 4] 1 is a front view showing a medium having a thickness that varies partially in the transport direction, a pressing roller, an abutment roller, and the like in an embodiment; [Diagram 5] FIG. 13 is a left side view showing a medium having a thickness that varies partially across the width direction, a pressing roller, an abutment roller, and the like, in a modified example of an embodiment. [Figure 6] 13 is an enlarged left side view showing the internal structure of a medium (cardboard), a pressing roller, an abutment roller, and the like in a modified example of the embodiment. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] An inkjet printing apparatus according to an embodiment of the present invention will now be described with reference to the drawings.

[0011] FIG. 1 is a front view showing an inkjet printing apparatus 1. As shown in FIG.

[0012] FIG. 2 is a perspective view showing the bottom surface 12a of the head holder 12. As shown in FIG.

[0013] FIG. 3 is a left side view showing a medium M1, a pressing roller 21, an abutment roller 31, etc., the thickness of which varies partially in the width direction D2.

[0014] With regard to the up-down, front-back, and left-right directions shown in Figures 1 to 3 and Figures 4 to 6 described below, the orientation of the transport direction D1 and width direction D2 of the media M1, M2 will change appropriately depending on the configuration of the inkjet printing device 1, but the up-down direction is the vertical direction, and the front-back and left-right directions are the horizontal directions.

[0015] The inkjet printing apparatus 1 shown in FIG. 1 includes a printing unit 10, a plurality of pressing rollers 21, a plurality of abutment rollers 31, and a belt conveying unit 40.

[0016] The printing unit 10 has a plurality of inkjet heads 11 (for example, 12 as shown in FIG. 2) and a head holder 12.

[0017] 2, the printing unit 10 has two sets of six inkjet heads 11 arranged in a staggered pattern along a width direction D2 (main scanning direction) of the medium M1 perpendicular to a transport direction D1 (sub-scanning direction) of the medium M1, for a total of 12 inkjet heads. That is, the six inkjet heads 11 in one set arranged along the width direction D2 are arranged in two rows with their positions in the transport direction D1 shifted alternately. As an example, the six inkjet heads 11 in one set eject ink of two colors (e.g., black (K) and cyan (C)), and the six inkjet heads 11 in the other set eject ink of two colors (e.g., magenta (M) and yellow (Y)) different from those in the one set.

[0018] In this embodiment, a plurality of inkjet heads 11 are arranged and eject ink vertically downward, but the number of inkjet heads 11 may be one or more, and the inkjet head 11 may eject ink in a direction other than vertically downward (for example, horizontally). Furthermore, the medium M1 is, for example, a craft bag, but it may be cardboard like the medium M2 in a modified example described later, or may be other medium.

[0019] The head holder 12 has, for example, a rectangular parallelepiped shape and holds a plurality of inkjet heads 11. A bottom surface 12a of the head holder 12 shown in FIG. 2 is provided with a plurality of rectangular head holes 12b into which parts of the inkjet heads 11 are inserted. The bottom surface 12a of the head holder 12 is also provided with a plurality of rectangular roller holes 12c into which parts of abutment rollers 31 described below are inserted. In FIG. 2, the outline of the bottom surface 12a of the head holder 12 is represented by a two-dot chain line (imaginary line). In FIG. 2 and FIG. 3, as well as FIG. 4 to FIG. 6 described below, the head holder 12 is omitted from illustration.

[0020] 1 and 3 urge the medium M1 toward the inkjet head 11 (upward in this embodiment). The pressing rollers 21 are, for example, rubber rollers. Each of the pressing rollers 21 rotates around a rotating shaft 22 rotatably supported by a support section 23 in contact with the medium M1 transported by the belt 41. The support section 23 has, for example, a bottom surface portion (lower end portion) and a pair of side surfaces rising from the bottom surface portion and rotatably supporting the rotating shaft 22, forming a U-shape that opens upward.

[0021] As shown in Fig. 3, the support portion 23 is biased toward the inkjet head 11 by the elastic force of the elastic body 24. As a result, the pressing roller 21 supported by the support portion 23 via the rotating shaft 22 biases the medium M1 toward the inkjet head 11 (in Fig. 1, the pressing roller 21 is indicated by an arrow and the elastic body 24 and the like are omitted from the illustration). In this way, each of the multiple pressing rollers 21 individually receives the elastic force of the elastic body 24, and therefore independently biases the medium M1 toward the inkjet head 11. The elastic body 24 is, for example, a compression spring, and is fixed at its lower end to an immovable member (not shown) within the belt 41 described later.

[0022] 3, the multiple abutting rollers 31 are disposed at positions facing the multiple pressing rollers 21, and are abutted against the medium M1 urged by the multiple pressing rollers 21. Since each of the multiple abutting rollers 31 is fixed in position at a common height for the multiple abutting rollers 31, a head gap G is formed between the medium M1 and the inkjet head 11. The abutting rollers 31 are, for example, rubber rollers.

[0023] Each of the multiple abutting rollers 31 rotates around a rotating shaft 32 rotatably supported by a support portion 33 in contact with the medium M1 conveyed by the belt 41. The support portion 33 has, for example, a bottom surface portion (upper end portion) and a pair of side portions rising from the bottom surface portion and rotatably supporting the rotating shaft 32, forming a U-shape that opens downward. The support portion 33 is fixed, for example, to an immovable member (not shown) in the head holder 12. The abutting rollers 31 are preferably arranged so that the fixed position can be adjusted in the height direction. In this case, the head gap G can be arbitrarily adjusted according to the type, size, print contents, etc. of the medium M1. The abutting rollers 31 are preferably arranged on the bottom surface 12a (roller hole 12c) of the head holder 12, but may be arranged at a position separated from the head holder 12 in the width direction D2.

[0024] 4, the pressing roller 21 and the abutting roller 31 are located at the same positions as the inkjet heads 11 in the transport direction D1 of the medium M1. Eight pressing rollers 21 and abutting rollers 31 are arranged in accordance with the four rows of inkjet heads 11, four on one side (front side) of the inkjet heads 11 in the width direction D2 and four on the other side (rear side). As described above, the inkjet heads 11 are arranged in a staggered manner, and the positions of the inkjet heads 11 in the width direction D2 differ for each row, and the pressing roller 21 and the abutting roller 31 are located close to the inkjet heads 11 on the front side and rear side of the inkjet heads 11 in the width direction D2. Therefore, the positions of the pressing roller 21 and the abutting roller 31 in the width direction D2 also differ for each row of inkjet heads 11.

[0025] In particular, in the case of a medium M2 having high rigidity (easy to maintain height) such as a cardboard in a modified example described later, the pressing roller 21 and the abutting roller 31 may be disposed at a position slightly shifted upstream or downstream in the conveying direction D1 from the inkjet head 11 (separate positions in the conveying direction D1 without overlapping). When the pressing roller 21 and the abutting roller 31 are disposed at a position shifted upstream or downstream from the inkjet head 11 in the conveying direction D1, for example, they may be disposed at a position shifted downstream from the inkjet head 11 at the downstream end in the conveying direction D1, and shifted upstream from the inkjet head 11 at the upstream end in the conveying direction D1. The pressing roller 21 and the abutting roller 31 may also be disposed between two inkjet heads 11 adjacent to each other in the width direction D2.

[0026] The belt conveying section 40 shown in FIG. 1 includes a belt 41 and a plurality of pulleys 42. The belt 41 is an endless belt and is stretched over the plurality of pulleys 42. One of the pulleys 42 is a driving pulley, and the other pulleys 42 are driven pulleys. The driving pulley rotates by being driven by a conveying driving section (e.g., an actuator such as a motor) not shown, and rotates the pulley 42. As a result, the belt 41 conveys the medium M1 in the conveying direction D1 while rotating. Note that the belt 41 is supported from below by the pulley 42 and the abutting roller 31, but since it is desirable that the belt 41 bends downward by the folded portion M1a (e.g., a portion folded back multiple times) of the medium M1 and the elastic body 24 is compressed, it is desirable that no supporting member is disposed below the conveying portion of the medium M1.

[0027] The above-mentioned inkjet printing device 1 may further include a supply unit (loading table, supply rollers, supply belt, etc.) that supplies medium M1 to the printing unit 10, a discharge unit (loading table, discharge rollers, discharge belt, etc.) that discharges medium M1 printed by the printing unit 10, a display that displays various information, an input unit that accepts user operations, etc.

[0028] First, consider a case in which the thickness of the medium M1 varies partially in the width direction D2 due to the folded portion M1a of the medium M1 being located on one side (front side) in the width direction D2, as shown in Fig. 3. In this case, the pressing roller 21 on the front side urges the folded portion M1a upward toward the inkjet head 11 (the abutment roller 31 side) in a state in which the elastic body 24 is largely compressed (long downward arrow) by the folded portion M1a, which is relatively thick, of the medium M1. On the other hand, the pressing roller 21 on the rear side urges the medium M1 upward toward the inkjet head 11 (the abutment roller 31 side) in a state in which the elastic body 24 is only slightly compressed (short downward arrow) by the relatively thin portion of the medium M1 (portion other than the folded portion M1a).

[0029] As a result, a head gap G between the medium M1 having the folded portion M1a and the inkjet head 11 can be formed to the length between the lower end of the abutment roller 31 and the inkjet head 11 across the width direction D2.

[0030] Next, unlike the example of FIG. 3, a case will be considered in which the thickness of the medium M1 varies partially along the conveying direction D1 as a result of the folded portion M1b of the medium M1 being located downstream (right side) in the conveying direction D1, as shown in FIG. 4. In this case, the pressing roller 21 on the downstream side of the conveying direction D1 (the pressing roller 21 second from the right in FIG. 4) urges the folded portion M1b upward toward the inkjet head 11 side (the abutting roller 31 side) in a state in which the elastic body 24 is largely compressed (long downward arrow) by the folded portion M1b of the medium M1, which is relatively thick. On the other hand, the pressing roller 21 on the upstream side of the conveying direction D1 (the pressing roller 21 first and second from the left in FIG. 4) urges the medium M1 upward toward the inkjet head 11 side (the abutting roller 31 side) in a state in which the elastic body 24 is slightly compressed (short downward arrow) by the portion of the medium M1 that is relatively thin (portion other than the folded portion M1b).

[0031] As a result, a head gap G between the medium M1 having the folded portion M1b and the inkjet head 11 can be formed in the transport direction D1, the length being between the lower end of the abutment roller 31 and the inkjet head 11. Note that the pressing rollers 21 (the pressing rollers 21 on one or the other side in the width direction D2 described above) positioned side by side in the transport direction D1 may have, for example, a plurality of support parts 23 fixed integrally, and may integrally (not independently) urge the medium M1 toward the inkjet head 11. However, in order to transport the medium M1 whose thickness varies partially in the transport direction D1, it is preferable that the pressing rollers 21 aligned in the transport direction D1 on the front side or rear side of the inkjet head 11 in the width direction D2 independently urge the medium M1 toward the inkjet head 11.

[0032] FIG. 5 is a left side view showing the medium M2, the pressing roller 21, the abutment roller 31, etc. in a modified example of the present embodiment.

[0033] FIG. 6 is an enlarged left side view showing the internal structure of the medium M2, the pressing roller 21, the abutment roller 31, and the like.

[0034] In this modification, the medium M2 is made of cardboard and has high rigidity, and the position (height) of the medium M2 can be maintained by the nip between the pressing roller 21 and the abutment roller 31 without the need for the belt 41. Therefore, the belt 41 (belt conveying section 40) is omitted. Note that the medium M2 can be guided by a guide plate or the like instead of the belt 41, and therefore the belt 41 can be omitted regardless of the type of the medium M2.

[0035] Since the belt conveying unit 40 is omitted, one of the pressing roller 21 and the abutting roller 31 is a driving roller and the other is a driven roller in order to convey the medium M2. The driving roller is rotated by the drive of a conveying driving unit (for example, an actuator such as a motor) not shown in the figure, and conveys the medium M2.

[0036] 6, the medium M2 has a corrugated core M2b between a pair of upper and lower flat liners M2c. The widths W, W of the pressing roller 21 and the abutting roller 31 in the width direction D2 are preferably equal to or greater than the pitch P of the corrugation of the core M2b of the medium M2 (the distance between the joints with the liners M2c). This makes it possible to prevent the pressing roller 21 and the abutting roller 31 from denting the liner M2c.

[0037] When there are multiple types of media M2 to be printed on in the inkjet printing device 1, the width W of the pressing roller 21 and the abutting roller 31 in the width direction D2 should be longer than the pitch P of the type of medium M2 for which the pitch P is maximum. For example, when the medium M2 is cardboard, the pitch P of the corrugations of the core M2b is, for example, approximately 9.3 mm at maximum including a tolerance. In the example of Fig. 6, the width W of the pressing roller 21 and the width W of the abutting roller 31 are the same, but they may be different. Even in this case, the width W of each of the pressing roller 21 and the abutting roller 31 should be greater than or equal to the pitch P of the corrugations of the core M2b.

[0038] As shown in Fig. 5, a case will be considered in which the thickness of the medium M2 varies partially in the width direction D2 due to the fact that the bonded portion M2a of the medium M2 is located on one side (the front side) in the width direction D2. In this case, similar to the example shown in Fig. 3, the pressing roller 21 on the front side urges the bonded portion M2a upward toward the inkjet head 11 side (the abutment roller 31 side) in a state in which the elastic body 24 is largely compressed (long downward arrow) by the bonded portion M2a, which is relatively thick, of the medium M2. On the other hand, the pressing roller 21 on the rear side urges the medium M2 upward toward the inkjet head 11 side (the abutment roller 31 side) in a state in which the elastic body 24 is only slightly compressed (short downward arrow) by the relatively thin portion of the medium M2 (portion other than the bonded portion M2a).

[0039] As a result, a head gap G between the medium M2 having the bonded portion M2a and the inkjet head 11 can be formed to the length between the lower end of the abutment roller 31 and the inkjet head 11 in the width direction D2.

[0040] In addition, in this modified example, a case where the thickness of the medium M2 varies partially in the transport direction D1 due to the fact that the bonded portion M2a of the medium M2 is located on the downstream side or the upstream side of the transport direction D1 is not shown. However, as in the example shown in Fig. 4, the compression amount of the pressing roller 21 varies between the downstream side and the upstream side of the transport direction D1, and the head gap G between the medium M2 having the bonded portion M2a and the inkjet head 11 can be formed to the length between the lower end of the abutment roller 31 and the inkjet head 11 in the transport direction D1.

[0041] In the above-described embodiment and its modified example, the inkjet printing device 1 includes an inkjet head 11, a plurality of pressing rollers 21, and a plurality of abutting rollers 31. The inkjet head 11 ejects ink onto the media M1, M2. The plurality of pressing rollers 21 urge the media M1, M2 toward the inkjet head 11. The plurality of abutting rollers 31 are disposed at positions facing the plurality of pressing rollers 21, and the media M1, M2 urged by the plurality of pressing rollers 21 are abutted against the plurality of abutting rollers 31, forming a head gap G between the media M1, M2 and the inkjet head 11. The plurality of pressing rollers 21 and the plurality of abutting rollers 31 include a pressing roller 21 and abutting roller 31 located on one side (front side) of the inkjet head 11 in a width direction D2 of the media M1, M2 perpendicular to the conveying direction D1 of the media M1, M2, and a pressing roller 21 and abutting roller 31 located on the other side (rear side) of the inkjet head 11 in the width direction D2. The pressing roller 21 located on one side of the inkjet head 11 in the width direction D2 and the pressing roller 21 located on the other side of the inkjet head 11 in the width direction D2 each independently press the media M1, M2 toward the inkjet head 11.

[0042] In this way, the pressing roller 21 located on one side of the inkjet head 11 in the width direction D2 and the pressing roller 21 located on the other side of the inkjet head 11 in the width direction D2 each independently press the media M1, M2 toward the inkjet head 11, so that even if the thicknesses of the media M1, M2 partially differ across the width direction D2 of the media M1, M2, the head gap G between the medium M2 and the inkjet head 11 can be formed to the length between the lower end of the abutment roller 31 and the inkjet head 11 across the width direction D2. Thus, according to this embodiment, it is possible to suppress fluctuations in the head gap G between the inkjet head 11 and the media M1, M2, which have partially different thicknesses. However, unlike the present embodiment, in an aspect in which the fluctuation of the head gap G cannot be suppressed, if the head gap G is set to match the thin portions of the media M1, M2, the head gap G narrows in the partially thick portions, which increases the risk of collision between the media M1, M2 and the inkjet head 11, and if the head gap G is set to match the thick portions of the media M1, M2, the head gap G widens in the partially thin portions of the media M1, M2, which causes a large amount of mist to scatter and image degradation. In contrast, in the present embodiment, the fluctuation of the head gap G between the media M1, M2, which have partially different thicknesses, and the inkjet head 11 can be suppressed, so that the above problems can be prevented from occurring.

[0043] In this embodiment and its modified example, the pressing roller 21 and the abutment roller 31 are located at the same position as the inkjet head 11 in the transport direction D1 of the media M1 and M2.

[0044] This makes it possible to further suppress fluctuations in the head gap G compared to when the positions of the pressing roller 21 and the abutment roller 31 in the transport direction D1 of the media M1, M2 are upstream or downstream of the inkjet head 11.

[0045] Moreover, in this embodiment, the inkjet printing apparatus 1 further includes a belt 41 that transports the medium M1, and the multiple pressing rollers 21 urge the medium M1 toward the inkjet head 11 via the belt 41.

[0046] This allows the belt 41 to maintain the position (height) of the medium M1, thereby further suppressing fluctuations in the head gap G.

[0047] In addition, in a modified example of this embodiment, the medium M2 is cardboard having a corrugated core M2b, and the widths W, W of the pressing roller 21 and the abutment roller 31 in the width direction D2 of the medium M2 are greater than or equal to the pitch P of the corrugation of the core M2b.

[0048] This makes it possible to prevent the pressing roller 21 and the abutting roller 31 from denting the liner M2c when the medium M2 is transported in a direction such that the center core M2b of the medium M2 is wavy in the width direction D2 of the medium M2. This also makes it possible to prevent transport defects from occurring in the medium M2.

[0049] In this embodiment, the abutment rollers 31 are disposed on the bottom surface 12a (roller holes 12c) of the head holder 12 that holds the inkjet head 11.

[0050] This allows the press roller 21 to urge the media M1, M2 toward the inkjet head 11 in the vicinity of the inkjet head 11. Therefore, fluctuations in the head gap G can be further suppressed.

[0051] The present invention is not limited to the above-described embodiment as it is, and the components can be modified and embodied in the implementation stage without departing from the gist of the invention. In addition, various inventions can be formed by appropriate combinations of the multiple components disclosed in the above-described embodiment. For example, all the components shown in the embodiment may be appropriately combined. Of course, various modifications and applications are possible without departing from the spirit of the invention. Some of the inventions described in the specification of this application are listed below.

[0052] [Appendix 1] An inkjet head that ejects ink onto a medium; a plurality of pressing rollers that press the medium toward the inkjet head; a plurality of abutment rollers that are disposed in positions opposite to the plurality of pressure rollers, against which the medium biased by the plurality of pressure rollers abuts, forming a head gap between the medium and the inkjet head; the plurality of pressing rollers and the plurality of abutting rollers include the pressing roller and the abutting roller located on one side of the inkjet head in a width direction of the medium perpendicular to a transport direction of the medium, and the pressing roller and the abutting roller located on the other side of the inkjet head in the width direction, The pressing roller positioned on one side of the inkjet head in the width direction and the pressing roller positioned on the other side of the inkjet head in the width direction each independently press the medium toward the inkjet head. 1. An inkjet printing apparatus comprising:

[0053] [Appendix 2] The pressing roller and the abutting roller are positioned at the same position as the inkjet head in the transport direction of the medium. 2. The inkjet printing apparatus according to claim 1.

[0054] [Appendix 3] Further comprising a belt for transporting the medium; The plurality of pressing rollers press the medium toward the inkjet head via the belt. 3. The inkjet printing apparatus according to claim 1 or 2.

[0055] [Appendix 4] the medium is corrugated cardboard having a corrugated core; The width of the pressing roller and the abutting roller in the width direction of the medium is equal to or greater than the pitch of the corrugations of the core. 4. The inkjet printing apparatus according to claim 1, [Explanation of symbols]

[0056] 1 Inkjet printing device 10 Printing Department 11 Inkjet head 12 Head holder 12a Bottom 12b Head hole 12c Roller hole 21 Pressing roller 22 Rotation axis 23 Support part 24 Elastic Body 31 Stop roller 32 Rotation axis 33 Support part 40 Belt conveyor 41 Belt 42 Pulley D1 Transport direction D2 width direction G Head Gap M1,M2 medium M1a, M1b Folded parts M2a Glued part M2b center core M2c Liner Pitch W width

Claims

1. An inkjet head that ejects ink onto a medium; a plurality of pressing rollers that press the medium toward the inkjet head; a plurality of abutment rollers that are disposed in positions opposite to the plurality of pressure rollers, against which the medium biased by the plurality of pressure rollers abuts, forming a head gap between the medium and the inkjet head; the plurality of pressing rollers and the plurality of abutting rollers include the pressing roller and the abutting roller located on one side of the inkjet head in a width direction of the medium perpendicular to a transport direction of the medium, and the pressing roller and the abutting roller located on the other side of the inkjet head in the width direction, The pressure roller located on one side of the inkjet head in the width direction and the pressure roller located on the other side of the inkjet head in the width direction each independently urge the medium toward the inkjet head.

1. An inkjet printing apparatus comprising:

2. The pressing roller and the abutting roller are positioned at the same position as the inkjet head in the transport direction of the medium.

2. The inkjet printing apparatus according to claim 1.

3. Further comprising a belt for transporting the medium; The plurality of pressing rollers press the medium toward the inkjet head via the belt.

3. The inkjet printing apparatus according to claim 1, wherein the inkjet printing apparatus is a liquid ejection apparatus.

4. the medium is corrugated cardboard having a corrugated core; The width of the pressing roller and the abutting roller in the width direction of the medium is equal to or greater than the pitch of the corrugations of the core.

3. The inkjet printing apparatus according to claim 1, wherein the inkjet printing apparatus is a liquid ejection apparatus.

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