JP2023095000A - Droplet discharge head unit, droplet discharge device and assembly method of droplet discharge head unit - Google Patents

Abstract

To provide a droplet discharge head unit which suppresses the reduction in the print quality.SOLUTION: A droplet discharge head unit 50 which includes a plurality of droplet discharge heads 60 having a plurality of nozzles N discharging liquid comprises: an attachment member 52 which can attach the plurality of droplet discharge heads 60; and a cover member 51 which prevents contact by a user to the plurality of droplet discharge heads 60 by covering the periphery of the plurality of droplet discharge heads 60. The droplet discharge head unit suppresses the positional deviation due to the contact by the user to the droplet discharge head 60 that is highly accurately aligned and the reduction in the print quality following the positional deviation.SELECTED DRAWING: Figure 2

Description

The present invention relates to a droplet ejection head unit, a droplet ejection device, and a method of assembling the droplet ejection head unit.

2. Description of the Related Art Conventionally, there has been known a droplet ejection head that ejects liquid onto a predetermined recording surface of a recording medium at appropriate timing based on image data to record an image on the recording surface.

For the purpose of further increasing the dot pitch during image recording, there is known a droplet discharge head unit formed by mounting a plurality of droplet discharge heads on a single mounting member ( For example, see Patent Document 1).

JP 2016-107401 A

However, in the invention of Patent Document 1, the upper part of the droplet ejection head unit is opened, and the user can directly touch the droplet ejection head that is aligned with high accuracy. Therefore, there is a problem that when the user directly touches it, the position of the droplet discharge head is shifted, resulting in deterioration of print quality.

SUMMARY OF THE INVENTION An object of the present invention is to provide a liquid droplet ejection head unit in which deterioration of print quality is less likely to occur.

In order to solve the above problems, the invention according to claim 1,
A droplet ejection head unit comprising a plurality of droplet ejection heads having a plurality of nozzles for ejecting liquid,
a mounting member for mounting the plurality of droplet discharge heads;
and a cover member that covers the periphery of the plurality of droplet ejection heads to prevent a user from coming into contact with the plurality of droplet ejection heads.

The invention according to claim 2 is the droplet discharge head unit according to claim 1,
The cover member is characterized in that a second surface opposite to the first surface on the nozzle side has an opening area smaller than that of the first surface.

The invention according to claim 3 is the droplet discharge head unit according to claim 1 or 2,
each of the plurality of droplet discharge heads includes a nozzle plate provided with the nozzle;
The plurality of droplet discharge heads are attached to the attachment member with a gap between them.

The invention according to claim 4 is the droplet ejection head unit according to claim 3,
A mist entry prevention member is provided that is inserted into the gap between the plurality of droplet discharge heads.

The invention according to claim 5 is the droplet discharge head unit according to any one of claims 1 to 4,
a first connector connected to a control board for controlling ejection driving of the droplet ejection heads;
a second connector connected to a liquid tank outside the droplet ejection head,
The first connector and the second connector are joined to the cover member by a joining material.

The invention according to claim 6 is the droplet ejection head unit according to any one of claims 1 to 5,
The plurality of droplet ejection heads are characterized by ejecting different liquids.

The invention according to claim 7 is the droplet discharge head unit according to any one of claims 1 to 6,
The attachment member is characterized by being made of metal.

The invention according to claim 8 is the droplet discharge head unit according to any one of claims 1 to 7,
The cover member is provided so as not to come into contact with the plurality of droplet discharge heads positioned inside the cover member.

The invention according to claim 9 is the droplet discharge head unit according to any one of claims 1 to 8,
the cover member includes a suppressing portion that suppresses bending of the cover member,
The suppressing portion is characterized by coming into contact with the mounting member.

The invention according to claim 10 is the liquid droplet ejection head unit according to any one of claims 1 to 9,
The cover member has a connection port that can be connected to a pressure adjusting device that pressurizes or decompresses the inside of the cover member.

The invention according to claim 11 is the droplet ejection head unit according to any one of claims 1 to 10,
The mounting member and the member of the droplet discharge head that contacts the mounting member are made of the same material.

According to a twelfth aspect of the invention, there is provided a droplet discharge device comprising:
A liquid droplet ejection head unit according to any one of claims 1 to 11 is provided.

The invention according to claim 13,
A method for assembling a droplet ejection head unit including a plurality of droplet ejection heads having a plurality of nozzles for ejecting liquid, comprising:
a first mounting step of mounting the plurality of droplet discharge head units on a mounting member;
a second mounting step of mounting a cover member on the mounting member so as to cover the plurality of droplet discharge head units and prevent a user from contacting the plurality of droplet discharge heads;
characterized by having

According to the present invention, it is possible to provide a droplet ejection head unit that is less susceptible to deterioration in print quality.

1 is a perspective view showing a schematic configuration of an inkjet recording apparatus according to one embodiment of the present invention; FIG. 1 is a perspective view of an inkjet head unit according to an embodiment of the invention; FIG. 3 is a perspective view of the inkjet head unit with the cover member removed; FIG. 4 is a top view of the inkjet head unit of FIG. 3; FIG. 4 is a bottom view of the inkjet head unit of FIG. 3; FIG. 5 is a cross-sectional view of the inkjet head unit of FIG. 4 taken along line VI-VI. FIG. FIG. 5 is a cross-sectional view of the inkjet head unit of FIG. 4 taken along line VII-VII; It is a top perspective view of a cover member. It is a bottom view of a cover member. FIG. 3 is a top view schematically showing a simplified mounting structure of the inkjet head to the mounting member; FIG. 11 is a perspective view of an inkjet head unit according to a modified example; FIG. 11 is a perspective view of an inkjet head unit according to a modified example;

[Outline of embodiment]
Preferred embodiments of the present invention will be described below with reference to the drawings. However, the scope of the invention is not limited to the illustrated examples. Moreover, in the following description, the same reference numerals are given to the components having the same function and configuration, and the description thereof will be omitted.

In the following description, the lateral direction of the droplet ejection head is defined as the front-rear direction, and the longitudinal direction is defined as the left-right direction. is described as the vertical direction.

[Configuration of Inkjet Recording Apparatus]
First, a configuration example of an inkjet recording apparatus 10 including an inkjet head unit 50, which is a droplet ejection head unit, will be disclosed as a droplet ejection apparatus according to the present embodiment.
FIG. 1 is a diagram showing a schematic configuration of an inkjet recording apparatus 10, which is an embodiment of the present invention.
The inkjet recording apparatus 10 includes a transport section 20, a print unit 30, and the like.

(Conveyor)
The conveying unit 20 includes a ring-shaped conveying belt 20c whose inner side is supported by two conveying rollers 20a and 20b that rotate around a rotation axis extending in the left-right direction in FIG. In the conveying unit 20, the conveying roller 20a rotates according to the operation of a conveying motor (not shown) in a state where the recording medium M is placed on the conveying surface of the conveying belt 20c, and the conveying belt 20c circulates. The recording medium M is conveyed in the front-rear direction.

(recoding media)
The recording medium M can be, for example, a sheet of paper cut to a certain size. The recording medium M is supplied onto the conveying belt 20c by a paper feeding device (not shown), and after ink is ejected from the print unit 30 to record an image, the recording medium M is discharged from the conveying belt 20c to a predetermined paper discharging section.

As the recording medium M, a long recording medium such as roll paper or continuous form paper may be used. Moreover, as the recording medium M, in addition to paper such as plain paper and coated paper, it is possible to use various media such as fabric or sheet-like resin, on which ink that has landed on the surface can be fixed.

(Print unit)
The print unit 30 includes a plurality of inkjet head units 50 (see FIG. 2).
The print unit 30 prints an image on the recording medium M transported by the transport unit 20 by ejecting ink from each inkjet head unit 50 at appropriate timing based on the image data.

Note that in FIG. 1, four print units 30 corresponding to four colors of ink, yellow (Y), magenta (M), cyan (C), and black (K), are arranged from the upstream side in the conveying direction of the recording medium M. Although the case where the colors are arranged in the order of Y, M, C, and K at predetermined intervals is illustrated, the present invention is not limited to this. That is, the number of print units 30 included in the inkjet recording apparatus 10 may be three or less or five or more.

[Configuration of inkjet head unit]
FIG. 2 is a perspective view showing one inkjet head unit 50 according to this embodiment. FIG. 3 is a perspective view showing the inkjet head unit 50 with the cover member 51 removed.
The inkjet head unit 50 mainly includes a plurality of inkjet heads 60, a cover member 51 that covers the plurality of inkjet heads 60, a mounting member 52 to which the plurality of inkjet heads 60 are attached, and a mist entry prevention member 53 (see FIG. 5). prepared for.

In addition, although the case where the inkjet head unit 50 is provided with the two inkjet heads 60 below is illustrated, it is not restricted to this. That is, the inkjet head unit 50 may be configured to include three or more inkjet heads 60 .
In the following description, a case in which a plurality of inkjet heads 60 are arranged in parallel with each other in the direction perpendicular to the nozzle row is illustrated, but the present invention is not limited to this.

[Configuration of inkjet head]
4 is a top view of FIG. 3, and FIG. 5 is a bottom view of FIG. 6 is a cross-sectional view along line VI-VI of FIG. 4, and FIG. 7 is a cross-sectional view along line VII-VII of FIG.
As shown in FIG. 5, each inkjet head 60 is provided on the bottom surface of the nozzle end portion 61, and includes a nozzle plate 62 having nozzles N formed thereon and a driving mechanism for ejecting ink from each nozzle N. head chips (not shown). Further, as shown in FIGS. 2 to 4, as connecting portions exposed from the cover member 51, a first connector 63 is provided on the upper surface of each inkjet head 60, and second connectors 64 are provided on the left and right portions of the inkjet head 60. .

(nozzle plate)
As shown in FIG. 5, the nozzle plate 62 is a flat plate that is elongated in the left-right direction and arranged horizontally.

Each nozzle N is composed of, for example, four nozzle rows parallel to each other in the horizontal direction at a uniform nozzle pitch (referred to as P). The four nozzle rows are arranged at regular intervals in the front-rear direction, and the second nozzle row in the front-rear direction is P/2 to the left (or right) of the first nozzle row. ) are offset. Also, the third nozzle row is offset leftward (or rightward) by P/4 with respect to the first nozzle row. Also, the fourth nozzle row is offset leftward (or rightward) by P/2 with respect to the third nozzle row.
In addition, the two inkjet heads 60 included in the inkjet head unit 50 are attached to the mounting member 52 such that one of them is offset leftward (or rightward) from the other by P/8.

That is, a total of eight nozzle rows of the two inkjet heads 60 that constitute the inkjet head unit 50 are arranged with a shift of P/8 in the horizontal direction in order. Therefore, these two inkjet heads 60 can realize high-resolution dot formation with a dot pitch of P/8.

The inks ejected from the two inkjet heads 60 may be the same ink, but it is preferable to use different inks, because they can correspond to various image forming modes.
The “different inks” include inks containing different pigments (that is, inks of different colors) when the droplet ejection head is the inkjet head 60 as in the present embodiment. shall be taken.

(first connector)
The first connector 63 is a connection portion with a control board (not shown) of the print unit 30 that controls the ink ejection operation of the inkjet head 60 .
The head chip is formed with ink flow paths leading to individual nozzles N of the nozzle plate 62 . Piezoelectric elements for ejecting ink from the nozzles N are individually provided in these ink flow paths. A wiring for applying a drive voltage to each piezoelectric element is connected to a first connector 63 provided on the top of the inkjet head 60 .
In this configuration, the first connector 63 is cable-connected to the drive circuit of the control board, and ink is ejected from the nozzles N by receiving drive signals from the drive circuit.

(Second connector)
The second connector 64 is a connection portion for connection with an ink tank (not shown) or a waste liquid tank (not shown) as a liquid tank outside the inkjet head 60 .
Specifically, the second connector 64 includes an inlet 641 that supplies ink to each inkjet head 60 through a supply pipe connected to an ink tank, and each inkjet head through a discharge pipe connected to a waste liquid tank. An outlet 642 for discharging ink from the head 60 is provided. Both the inlet 641 and the outlet 642 are connected to a manifold (not shown) of the inkjet head 60 .
The second connector 64 may be provided on the upper surface of the inkjet head 60, like the first connector 63.

(Cover member)
8 is a top perspective view showing only the cover member 51, and FIG. 9 is a bottom view.
The cover member 51 is fitted on the mounting member 52 and/or the inkjet head 60 so as to cover the periphery of each inkjet head 60 excluding the nozzle plate 62, the first connector 63 and the second connector 64, for example. It is attached. In addition, the displacement of the ink jet head 60 caused by the user's contact and the resulting deterioration in print quality are suppressed.
The cover member 51 has a lower surface side opening 511 and an upper surface side opening 512 which are openings on the lower surface and the upper surface, respectively, and a suppressing portion 513 on the lower end of the front surface.

{Lower side opening}
As shown in FIGS. 8 and 9 , the lower surface side opening 511 is an opening provided in the first surface of the cover member 51 on the nozzle N side (lower surface side) of the inkjet head 60 . The lower surface side opening 511 is one opening for accommodating two inkjet heads 60 therein, as shown in FIG.

{Top side opening}
The upper surface side opening 512 is an opening provided on the second surface (upper surface side) of the cover member 51 opposite to the first surface. As shown in FIG. 2, the upper surface side opening 512 is an opening for exposing the first connector 63 to the outside of the cover member 51 so that the first connector 63 can be connected to the control board.

In particular, as shown in FIG. 9, in the cover member 51, the opening area of the upper surface side opening 512 on the second surface side is smaller than the opening area of the lower surface side opening 511 on the first surface side. is provided as follows.
By doing so, it becomes difficult for an airflow to flow from the lower surface side opening 511 toward the upper surface side opening 512 (that is, toward the inside of the cover member 51). In addition, it is possible to prevent the ink mist from entering the cover member 51 along with the air current and accumulating on the inkjet head 60, thereby preventing the print quality from deteriorating.

{Suppressor}
As shown in FIGS. 2, 8 and 9, the suppressing portion 513 is a convex portion provided at the lower end portion of the front portion of the cover member 51 and abutting on the mounting member 52 . By providing the suppressing portion 513 , even if the user touches the cover member 51 , the stress is released to the mounting member 52 contacting the suppressing portion 513 , thereby suppressing the bending of the cover member 51 itself. Therefore, it is possible to prevent the cover member 51 from coming into contact with the ink jet head 60 located inside and causing a positional deviation.

Note that the formation location of the suppressing portion 513 is not limited to the lower end portion of the front surface portion of the cover member 51 . For example, the suppressing portion 513 may be provided at the lower end of the rear surface portion of the cover member 51 or the lower end portions of the left and right surfaces. However, the front and rear surfaces of the cover member 51, which are relatively wide, are more flexible than the left and right surfaces, which are relatively narrow. A portion 513 is preferably provided.

Moreover, it is preferable to use a resin having a relatively low coefficient of thermal expansion as a raw material for the cover member 51 .
By doing so, when the inkjet head 60 located inside generates heat, it is possible to prevent the cover member 51 from bending due to the heat.

Specifically, it is preferable to use PI (polyimide), PPS (polyphenylene sulfide), LCP (Liquid Crystal Polymer), PEEK (polyether ether ketone), or the like as a raw material for the cover member 51 . It is more preferable that glass filler, carbon filler, inorganic filler, particles, fibers, and the like are appropriately added, but the present invention is not limited to this.

Also, the cover member 51 is provided so as not to come into contact with the two inkjet heads 60 positioned therein.
In this way, even if the user touches the cover member 51 and the cover member 51 bends, the ink jet head 60 located inside does not come into contact with the ink jet head 60 , thereby suppressing the displacement of the ink jet head 60 . can.

In addition, the cover member 51 is adhered to the first connector 63 and the second connector 64 with a predetermined bonding material while attached to the mounting member 52 . As the bonding material, for example, an adhesive, an O-ring, or any other suitable known material can be arbitrarily used.
By doing so, even if the user touches the first connector 63 and the second connector 64 exposed from the cover member 51, the stress is transmitted to the cover member 51 and escapes to the mounting member 52. , the positional deviation of the inkjet head 60 can be suppressed.
In addition, when the openings of the cover member 51 for exposing the first connector 63 and the second connector 64 are blocked by the bonding material, the air flow from the lower surface side opening 511 toward the opening is less likely to occur. Therefore, as described above, it is possible to prevent the print quality from deteriorating due to the ink mist.

(Mounting member)
The mounting member 52 is, for example, a substantially rectangular flat plate in top view, to which two inkjet heads 60 are mounted. The mounting member 52 is mounted on a carriage (not shown) that mounts the inkjet head unit 50 and adjusts the distance between the nozzles N of the inkjet head 60 and the recording medium M.
Two insertion portions 521 are formed through the approximate center of the mounting member 52, into which the nozzle end portions 61 of the two inkjet heads 60 are inserted from above. Further, the mounting member 52 is provided with reference pins 522 protruding downward from the lower surface thereof at the left and right ends thereof.

{Insert}
As shown in FIG. 5, the insertion portion 521 has a substantially rectangular shape, and its longitudinal direction is parallel to the left-right direction. By inserting the nozzle end portion 61 into the insertion portion 521 , the inkjet head 60 is attached to the attachment member 52 . At this time, the nozzle rows formed on the nozzle plate 62 are aligned in the horizontal direction.

Each inkjet head 60 needs to be precisely positioned and adjusted with respect to the mounting member 52 as the nozzles N become denser and more precise. Therefore, when the nozzle end portion 61 of the inkjet head 60 is inserted, the insertion portion 521 has a margin for position adjustment between the side surface portion around the nozzle end portion 61 and the inner edge portion of the insertion portion 521 . It is formed to a dimension such that a gap is formed.

It should be noted that the mounting member 52 is preferably made of metal.
By doing so, when the inkjet head 60 generates heat, the heat can be released from the inside of the cover member 51 more efficiently. Specifically, it is preferable to use an aluminum alloy for the mounting member 52, but the material is not limited to this.

Moreover, the mounting member 52 and the nozzle end portion 61 are preferably made of the same material.
By doing so, the thermal expansion coefficients of the nozzle end portion 61 and the mounting member 52, which is the contact portion of the nozzle end portion 61, are the same. The applied thermal stress is minimized, and positional displacement of the inkjet head 60 can be suppressed.

(Mounting structure of inkjet head to mounting member)
A mounting structure of the inkjet head 60 with respect to the mounting member 52 will be described.
FIG. 10 is a top view schematically showing a simplified mounting structure of the inkjet head 60 to the mounting member 52. As shown in FIG. In FIG. 10, nozzles N that can be seen only from the bottom side are shown for the sake of convenience. Also, these nozzles N are shown with larger nozzle diameters and nozzle pitches than in reality for clarity of explanation.

The inkjet head 60 has flange-like extensions 65 extending leftward and rightward at both left and right end portions of the nozzle end portion 61 . Through-holes penetrating vertically are formed in these extending portions 65 , and the inkjet head 60 can be fixed to the mounting member 52 through screws 66 . The diameters of the through holes of these extending portions 65 are all larger than the diameter of the screws 66 and have play. Loosening the screws 66 allows the position of the ink jet head 60 to be adjusted, and tightening the screws 66 allows the position of the ink jet head 60 to be adjusted. can be fixed to

In addition, an inclined portion 67 inclined at 45 degrees with respect to the front-rear direction is formed at one corner of one of the extending portions 65 (a left front oblique corner in FIG. 10). is formed with a V-shaped notch 68 .
When adjusting the position of the inkjet head 60, the screws 66 at both ends are loosened, and the spring member is pressed against the inclined portion 67 in a direction perpendicular to the inclined portion 67 (diagonally to the right in FIG. 10). direction). As a result, it is possible to achieve the same state as being pressed in both the rightward direction and the rearward direction.
Then, the position of the notch 68 is adjusted while being pushed back in the direction of the arrow shown (leftward) against the spring member, and the intermediate portion of the inkjet head 60 in the left-right direction is pushed against the spring member. Adjust the position while pushing back in the direction of the arrow (forward).

These position adjustment operations may be performed by performing a rotation operation while pressing the distal end portion of the adjusting screw member, which is moved back and forth by the rotation operation, against the adjustment position with respect to each adjustment position. Alternatively, the position may be adjusted by moving the screw member up and down by a rotating operation while bringing the conical surface of the screw member having the threaded portion and the conical surface into contact with the position indicated by the arrow from above. In any case, any adjustment material may be used as long as it contacts the notch 68 or the outer edge of the inkjet head 60 and causes a minute positional change in response to the amount of human manipulation.

By adjusting the positions of the two locations, the orientation and position of the inkjet head 60 in a plan view are changed. Nozzle N positioned on the first end side of any one nozzle row formed on the nozzle surface side of the inkjet head 60 (referred to as a reference nozzle n1) by position adjustment based on this attitude change and position change. is within the permissible range in the front-rear direction and the left-right direction with respect to the target position determined by the two reference pins 522 .

Furthermore, on the premise that the reference nozzle n1 satisfies the above conditions, the positional deviation of the nozzle N located on the second end side of the same nozzle row (the farthest nozzle nd) with respect to the reference nozzle n1 in the front-rear direction is allowed. Position while measuring so that it is within the range.
After the two conditions are satisfied by adjusting the position of the inkjet head 60 , the two screws 66 are tightened to fix the inkjet head 60 to the mounting member 52 . This completes the position adjustment of the inkjet head 60 .

As described above, each inkjet head 60 is positionally adjusted in the front-rear direction with respect to the mounting member 52 . There is a gap between them for adjustment.

In the inkjet head unit 50, if a gap is provided between the two inkjet heads 60, it is not limited to the point that the position of the inkjet head 60 can be adjusted, but has the following advantages.
- When the two inkjet heads 60 eject different inks, it is possible to prevent the different inks from being mixed.
- When one inkjet head 60 generates heat, it is possible to suppress transfer of heat to the other inkjet head 60 .
- When one inkjet head 60 breaks down, it can be easily replaced.

On the other hand, however, if a gap is provided between the two inkjet heads 60 or between the insertion portion 521 and the inkjet head 60, ink mist may enter through the gap. If the ink mist that has entered accumulates on the inkjet head 60, the inkjet head 60 may be contaminated or may solidify and adhere to the recording medium M, thereby degrading print quality.

(Mist intrusion prevention member)
Therefore, the ink jet head unit 50 is provided with a mist entry prevention member 53 that suppresses entry of the ink mist through the gap.
Specifically, a first mist entry prevention member 531 is interposed between the opposing surfaces of the nozzle end portion 61 of one inkjet head 60 and the nozzle end portion 61 of the other inkjet head 60 . In addition, between the front surface of the nozzle end portion 61 of one inkjet head 60 (front side) and the inner facing surface of the insertion portion 521, and the rear surface of the nozzle end portion 61 of the other inkjet head 60 (rear side) and the insertion portion A second mist entry prevention member 532 is interposed between each of the inner facing surfaces of 521 .

{First mist entry prevention member}
As shown in FIGS. 4 to 6, the first mist intrusion prevention member 531 is a substantially rectangular flat plate having a width in the left-right direction approximately equal to or slightly narrower than the width of the insertion portion 521, and the nozzle end of the inkjet head 60. It has the same shape as the front part or rear part of the part 61 excluding the extending part 65 . The first mist intrusion prevention member 531 is made of a synthetic resin sheet such as PET (polyethylene terephthalate), rubber, sponge, or other shrinkable material. A flexible material is used so that the ink jet head 60 is pressed so that the adjusted position does not change.
One side of the first mist entry prevention member 531 is attached in advance to one of the inkjet heads 60 with an adhesive tape, a double-sided tape, an adhesive, or the like. is done.

{Second mist entry prevention member}
As shown in FIGS. 5 and 6, the second mist intrusion prevention member 532 is a substantially rectangular sheet whose width in the left-right direction is about the same as or slightly narrower than that of the insertion portion 521, and is made of synthetic resin such as polyethylene terephthalate. It is made of flexible and soft material such as sheet, rubber, sponge, and the like. The second mist entry prevention member 532 is thinner than the gap between the insertion portion 521 and the inkjet head 60 in the front-rear direction.
The second mist entry prevention member 532 has its upper end adhered in advance to the upper surface of the mounting member 52 near the insertion portion 521 or to the inner surface of the insertion portion 521 with an adhesive tape, a double-sided tape, an adhesive, or the like. there is The lower end portion of the second mist entry prevention member 532 is in contact with the surface facing the insertion portion 521 of the nozzle end portion of the inkjet head 60 over the entire width in the left-right direction. Further, the portion between the upper end portion and the lower end portion of the second mist entry prevention member 532 is curved or bent so that the lower end portion is elastically kept in contact with the inkjet head 60 side.

In addition, the first end of the second mist entry prevention member 532 may be attached to the mounting member 52 and the second end may be directed upward and brought into contact with the inkjet head 60 . The first end of the second mist entry prevention member 532 may be attached to the inner surface of the insertion portion 521 of the mounting member 52 so that the second end of the second mist entry prevention member 532 contacts the inner surface of the insertion portion 521 of the attachment member 52 .

[Effect of the invention]
As described above, the droplet ejection head unit 50 according to the present embodiment includes a plurality of droplet ejection heads 60 having a plurality of nozzles N for ejecting liquid. 52 , and a cover member 51 that covers the periphery of the plurality of droplet ejection heads 60 to prevent a user from contacting the plurality of droplet ejection heads 60 .
According to this configuration, since the cover member 51 that covers the plurality of droplet ejection heads 60 prevents the user from touching the droplet ejection heads 60, the user can contact the droplet ejection heads 60 that are aligned with high accuracy. It is possible to suppress the misalignment caused by the misalignment and the deterioration of the print quality caused by the misalignment.

Further, in the cover member 51, the upper surface side opening 512 on the side opposite to the nozzle N has a smaller opening area than the lower surface side opening 511 on the nozzle N side.
According to this configuration, since it is difficult for the air current to flow into the cover member 51, it is possible to prevent the mist from entering the cover member 51 and accumulating on the droplet ejection head 60, thereby reducing print quality. be able to.

Further, the plurality of droplet ejection heads 60 each include a nozzle plate 62 provided with nozzles N, and the plurality of droplet ejection heads 60 are attached to the mounting member 52 with gaps between them.
According to this configuration, compared to the case where a plurality of inkjet heads 60 are provided on one nozzle plate 62, when the plurality of inkjet heads 60 eject different inks, the different inks are less likely to mix. can be suppressed.

In addition, when one inkjet head 60 generates heat, it is possible to suppress transfer of the heat to the other inkjet head 60 .
Moreover, when only one inkjet head 60 fails, it can be easily replaced.

The droplet ejection head unit 50 also includes a first mist entry prevention member 531 as a mist entry prevention member inserted in the gaps between the plurality of droplet ejection heads 60 .
According to this configuration, it is possible to prevent deterioration of print quality due to mist entering the droplet ejection head 60 and being deposited thereon.

In addition, the plurality of droplet ejection heads 60 includes a first connector 63 connected to a control board for controlling ejection driving of the droplet ejection heads 60, and a second connector connected to a liquid tank outside the droplet ejection heads 60. 64, and the first connector 63 and the second connector 64 are joined to the cover member 51 by a joining material.
According to this configuration, even if the user touches the first connector 63 or the second connector 64, the stress is transferred to the mounting member 52 through the cover member 51, thereby suppressing the displacement of the inkjet head 60. can do.
Further, since the openings of the cover member 51 for exposing the first connector 63 and the second connector 64 are closed with the joining material, mist is less likely to enter the cover member 51 .

Also, the plurality of droplet ejection heads 60 eject different inks.
With this configuration, the droplet ejection head unit 50 can be adapted to various printing modes.

Moreover, the mounting member 52 is made of metal.
According to this configuration, when the inkjet head 60 generates heat, the heat can be released from the inside of the cover member 51 more efficiently.

Also, the cover member 51 is provided so as not to come into contact with the plurality of droplet discharge heads 60 positioned inside the cover member 51 .
According to this configuration, even if the cover member 51 is bent due to the stress applied to the cover member 51 when the user touches the cover member 51, the cover member 51 does not come into contact with the inkjet head 60 located inside. Positional deviation of the head 60 can be suppressed.

In addition, the cover member 51 includes a suppressing portion 513 that suppresses bending of the cover member 51 , and the suppressing portion 513 contacts the mounting member 52 .
According to this configuration, even if the user touches the cover member 51 , the stress escapes from the suppressing portion 513 to the mounting member 52 . Therefore, it is possible to suppress the displacement of the inkjet head 60 due to the bending of the cover member 51 .

Further, the nozzle end portion 61 of the droplet discharge head 60 that contacts the mounting member 52 is made of the same material.
According to this configuration, when the inkjet head 60 generates heat, the thermal stress applied to the mounting member 52 is minimized, and displacement of the inkjet head 60 can be suppressed.

[Modification]
It should be noted that the present invention is not limited to the above embodiments, and various modifications are possible.
For example, the cover member 51 is not limited to those illustrated in FIGS.
For example, as shown in FIG. 11, a connection port 514 that is an opening is provided in the cover member 51, and a pressure adjustment device (non shown in the figure).
The pressure adjustment device is, for example, a pump device, and pressurizes the inside of the cover member 51 to suppress the entry of ink mist into the cover member 51 . In addition, by decompressing the inside of the cover member 51, the ink mist that has entered the inside of the cover member 51 can be sucked.

Note that the connection port 514 is not limited to the top surface of the cover member 51 as shown in FIG. 11, and may be formed at any desired location.

Moreover, as shown in FIG. 12, at least a portion of the cover member 51 may be formed in a mesh shape.
By doing so, when the ink-jet head 60 inside the cover member 51 generates heat, the heat is radiated out of the cover member 51 through the mesh openings.

Note that the mesh diameter of the mesh may be set arbitrarily as long as it is large enough to prevent a user's finger from coming into contact with the internal inkjet head 60 .

Also, in FIG. 12, only the front surface of the cover member 51 is meshed, but the present invention is not limited to this, and other surfaces may be meshed. Also, only a part of one surface may be meshed, or the entire surface may be meshed.

Also, in each drawing, the case where the cover member 51 is a single member is exemplified, but the cover member 51 is not limited to this, and may be a member made up of a plurality of parts.

In addition, the ink ejected from the inkjet head 60 is not particularly limited. For example, it may be a colorless coating ink or a liquid for forming a predetermined structure other than for image recording. Also, the present invention is not limited to the inkjet recording apparatus 10, and may be various droplet ejection apparatuses 10 that eject liquid droplets other than ink from the nozzles N to obtain films, structures, and the like.

In addition, the present invention is, of course, not limited to the above-described embodiments. That is, various modifications are possible, including the scope of the invention described in the claims and the scope of equivalents thereof.

10 Inkjet recording device (droplet ejection device)
50 inkjet head unit (droplet ejection head unit)
51 cover member 511 lower surface side opening 512 upper surface side opening 513 suppressing portion 514 connection port 52 mounting member 531 first mist entry prevention member (mist entry prevention member)
60 inkjet head (droplet ejection head)
62 nozzle plate 63 first connector 64 second connector N nozzle

Claims (13)

A droplet ejection head unit comprising a plurality of droplet ejection heads having a plurality of nozzles for ejecting liquid,
a mounting member for mounting the plurality of droplet discharge heads;
and a cover member that covers the periphery of the plurality of droplet ejection heads to prevent a user from coming into contact with the plurality of droplet ejection heads. 2. The droplet ejection head unit according to claim 1, wherein the cover member has a second surface opposite to the first surface on the nozzle side and has a smaller opening area than the first surface. each of the plurality of droplet discharge heads includes a nozzle plate provided with the nozzle;
3. The droplet ejection head unit according to claim 1, wherein the plurality of droplet ejection heads are attached to the attachment member with gaps therebetween. 4. The droplet ejection head unit according to claim 3, further comprising a mist entry prevention member inserted in the gap between the plurality of droplet ejection heads. a first connector connected to a control board for controlling ejection driving of the droplet ejection heads;
a second connector connected to a liquid tank outside the droplet ejection head,
5. The droplet ejection head unit according to claim 1, wherein the first connector and the second connector are joined to the cover member by a joining material. 6. The droplet ejection head unit according to claim 1, wherein the plurality of droplet ejection heads eject different liquids. 7. The droplet discharge head unit according to claim 1, wherein the mounting member is made of metal. 8. The droplet ejection according to any one of claims 1 to 7, wherein the cover member is provided so as not to contact the plurality of droplet ejection heads positioned inside the cover member. head unit. the cover member includes a suppressing portion that suppresses bending of the cover member,
9. The liquid droplet ejection head unit according to claim 1, wherein the suppressing portion abuts on the mounting member. 10. The liquid droplet ejection head unit according to any one of claims 1 to 9, wherein the cover member has a connection port that can be connected to a pressure adjusting device that pressurizes or decompresses the inside of the cover member. . 11. The droplet discharge head unit according to claim 1, wherein the mounting member and a member of the droplet discharge head that contacts the mounting member are made of the same material. A droplet ejection apparatus comprising the droplet ejection head unit according to claim 1 . A method for assembling a droplet ejection head unit including a plurality of droplet ejection heads having a plurality of nozzles for ejecting liquid, comprising:
a first mounting step of mounting the plurality of droplet discharge head units on a mounting member;
a second mounting step of mounting a cover member on the mounting member so as to cover the plurality of droplet discharge head units and prevent a user from contacting the plurality of droplet discharge heads;
A method for assembling a droplet discharge head unit, comprising:

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