Patent Application
20190375209
The present disclosure relates to a liquid ejecting head that ejects liquid such as ink.
A liquid ejecting head provided with a plurality of liquid ejecting modules is known in the art. Each liquid ejecting module is configured of a plurality of head units, and a first plate to which the respective head units are fixed. Each head unit is fixed to a first surface of the corresponding first plate.
Each first plate has a second surface opposite to the first surface. A second plate is provided on the second surfaces of the first plates. The second plate is provided along a plurality of first plates. The second plate closes gaps provided between the first plates, thereby preventing ink from collecting in these gaps (see Japanese Patent Application Publication No. 2016-55449, for example).
Each of the first plates and the second plate is formed with openings in communication with nozzles formed in the head units. However, in the conventional liquid ejecting head described above, damage to the nozzles may occur if a recording medium such as a paper enters these openings.
In view of the foregoing, it is an object of the present disclosure to provide a liquid ejecting head capable of suppressing damage to the nozzles.
In order to attain the above and other object, according to one aspect, the disclosure provides a liquid ejecting head including: a plurality of liquid ejecting modules each including a plurality of head units and a first plate, a second plate, and a protrusion. The plurality of liquid ejecting modules is arrayed in a first direction. The first plate has a first surface to which the plurality of head units is fixed and a second surface opposite to the first surface. The first plate has a thickness in a second direction. The second plate is disposed at the second surface of the first plate so as to extend along the plurality of liquid ejecting modules. The protrusion protrudes from the second plate in a direction away from the first plate.
The particular features and advantages of the embodiment(s) as well as other objects will become apparent from the following description taken in connection with the accompanying drawings, in which:
Next, a printer 1 provided with an inkjet head 4 according to a first embodiment will be described with reference to
As illustrated in
When conveyed through the printer 1, the recording sheet 100 is supported to an upper surface of the platen 3. The inkjet head 4 is disposed upward of the platen 3. The inkjet head 4 is a line-type head, and has a plurality of nozzles 15 (see
As illustrated in
The controller 7 is provided with a CPU (central processing unit), an ROM (read-only memory), an RAM (random access memory), and an ASIC (application-specific integrated circuit) that includes various control circuits. The controller 7 is connected to an external device 9, such as a personal computer, and can perform data communications with the external device 9. The controller 7 controls components in the printer 1 on the basis of print data received from the external device 9.
More specifically, the controller 7 controls the motor that drives the conveying rollers 5 and 6 to convey the recording sheet 100 in a conveying direction. At the same time, the controller 7 controls the inkjet head 4 to eject ink toward the recording sheet 100, whereby an image is formed on the recording sheet 100.
As illustrated in
As illustrated in
The six head units 12 of each liquid ejecting module 11 are fixed to an upper surface 13b (an example of a first surface) of the corresponding first plate 13. The first plate 13 is formed with six first openings 13a that penetrate the first plate 13 in the up-down direction. The first openings 13a extend obliquely relative to the front-rear direction and are arrayed in the left-right direction. The six first openings 13a are arrayed in correspondence with the six head units 12. The nozzles 15 and the corresponding first openings 13a are overlapped with each other in the up-down direction (i.e., a thickness direction of the first plate 13). The holder 14 has a plate shape and has a lower surface that retains the six head units 12.
A second plate 16 is provided below the four liquid ejecting modules 11. The second plate 16 has a rectangular shape that extends in the left-right direction along the four liquid ejecting modules 11. The second plate 16 has a front edge 16b and a rear edge 16c that are both bent upward. The four liquid ejecting modules 11 are interposed between the front edge 16b and rear edge 16c in the front-rear direction.
The second plate 16 has a lower surface 16e, and a plurality of second openings 16a that penetrate the second plate 16 in the up-down direction. The second openings 16a are arrayed in the left-right direction. As with the first openings 13a, the second openings 16a extend obliquely relative to the front-rear direction. The second openings 16a are arranged at positions in the left-right direction that are approximately the same as the positions of the first openings 13a in the four first plates 13. Thus, the second openings 16a and the first openings 13a are overlapped with each other in the up-down direction (i.e., the thickness direction of the first plates 13). Each second opening 16a has dimensions in the left-right direction and the front-rear direction greater than those of each first opening 13a. In other words, an area of each second opening 16a is greater than an area of each first opening 13a in a plan view. A lower surface 13c (an example of a second surface) of each first plate 13 is opposite to the upper surface 13b and fixed to an upper surface of the second plate 16. Protrusions 16d (described later) are provided on the lower surface 16e of the second plate 16. Each protrusion 16d is disposed between the neighboring second openings 16a.
As illustrated in
The plurality of protrusions 16d is provided on the lower surface 16e of the second plate 16 to protrude downward therefrom. Each protrusion 16d is disposed at a position between the neighboring second opening 16a. The protrusions 16d are integrally formed with the second plate 16. The protrusions 16d are formed in the second plate 16 through a raising (metalworking) technique, for example.
A first gap 21 is formed between the neighboring head units 12. If lines extending in the up-down direction along edges opposed to each other in two neighboring head units 12 are called extension lines L1 and L2, the first gap 21 is formed between the extension lines L1 and L2.
Some of the protrusions 16d are provided directly below the first gaps 21. If a line extending in the up-down direction through the left-right center of the protrusion 16d is called an extension line L3, the extension line L3 is positioned in the approximate left-right center between the extension lines L1 and L2. In other words, the protrusions 16d overlap the first gaps 21 in the up-down direction (the thickness direction of the first plates 13).
A second gap 22 is formed between the neighboring liquid ejecting modules 11. If lines extending in the up-down direction along edges opposed to each other in the two neighboring liquid ejecting modules 11 are called extension lines L4 and L5, the second gap 22 is formed between the extension lines L4 and L5.
Some of the protrusions 16d are provided directly below the second gaps 22. If a line extending in the up-down direction through the left-right center of this protrusion 16d is called an extension line L6, the extension line L6 is positioned in the approximate left-right center between the extension lines L4 and L5. In other words, the protrusions 16d overlap the second gaps 22 in the up-down direction (the thickness direction of the first plates 13).
In the printer 1 according to the first embodiment, since the protrusions 16d are formed on the second plate 16 to protrude downward therefrom, a predetermined distance is provided between the recording sheet 100 and the second openings 16a of the second plate 16. Thus, the protrusions 16d can prevent the recording sheet 100 from entering the second openings 16a, thereby avoiding damage to the nozzles 15.
Further, the nozzles 15, the first openings 13a, and the second openings 16a are overlapped with each other in the up-down direction. With this configuration, ink can be smoothly ejected through the nozzles 15.
Further, the outlines defining the first openings 13a and the outlines defining the second openings 16a overlap the head units 12 in the up-down direction. Accordingly, it is easy to apply load to the first plates 13 and second plate 16 in the manufacturing process for pressing the first plates 13 and second plate 16 up and down, thereby facilitating an operation for adhesively bonding the first plates 13 to the second plate 16.
Further, positional offset between the second plate 16 and first plates 13 may occur when the second plate 16 and first plates 13 are assembled together. However, since the area of each second opening 16a is larger than the area of each first opening 13a, the first openings 13a can easily be positioned inside the second openings 16a in a bottom view. This configuration can prevent the first openings 13a from being obstructed.
During the manufacturing process, a force directed downward is applied to the retaining plate 10 and a force directed upward is applied to the second plate 16 to press the first plates 13 and second plate 16 against each other in the up-down direction. At this time, a jig is disposed below the second plate 16. A plurality of through-holes in which the protrusions 16d are inserted is formed in the jig. After inserting the protrusions 16d into the corresponding through-holes, a force directed upward is applied to the second plate 16 through the jig. Since the protrusions 16d are provided directly below the first gaps 21, the jig overlaps the head units 12 in the up-down direction but does not overlap the first gaps 21. Accordingly, since the first plates 13 and the second plate 16 are interposed between the jig and the head units 12, the first plates 13 and second plate 16 can easily be bonded with the head units 12.
Further, since the protrusions 16d are provided directly below the second gaps 22, the jig overlaps the retaining plate 10 in the up-down direction without overlapping the second gaps 22 in the up-down direction. Accordingly, since the liquid ejecting modules 11 and the second plate 16 are interposed between the jig and the retaining plate 10, the liquid ejecting modules 11 can easily be bonded to the second plate 16. Further, since the head units 12 overlap the first plates 13 and second plate 16 in the up-down direction and do not overlap the second gaps 22, the head units 12 can be closely fixed to the first plates 13 and the second plate 16.
Next, a second plate 16A in an inkjet head 4 according to a second embodiment will be described with reference to
In other words, the central axis C2 is offset from the central axis C1 in an arraying direction of the liquid ejecting modules 11. Thus, if the second opening 116a has two open area with respect to the central axis C1, the open area of the second opening 116a containing the central axis C2 (i.e., the open area positioned leftward relative to the central axis C1) is greater than the open area of the second opening 116a on the opposite side (i.e., the open area positioned rightward relative to the central axis C1).
As illustrated in
Since the open area of the second opening 116a on the downstream side in the moving direction of the wiper blade 50A is greater than the open area of the second opening 116a on the upstream side with respect to the central axis C1 in the second plate 16A according to the second embodiment, a sufficient space in the second opening 116a is allocated downstream side of the nozzles 15 for transferring ink or foreign matter away from the nozzles 15, thereby enabling the ink or foreign matter to be easily scraped away from the nozzles 15.
Note that parts and components in the second embodiment having the same structure as those in the first embodiment are designated with the same reference numerals to avoid duplicating description.
Next, a second plate 16B in an inkjet head 4 according to a third embodiment will be described with reference to
The second plate 16B is formed with third openings 16f that penetrate the second plate 16B in the up-down direction. One third opening 16f is in communication with a left end of each second opening 16a at the front end thereof, and another third opening 16f is in communication with the left end of each second opening 16a at the rear end thereof. That is, the third opening 16f is open at each end portion of the second opening 16a in a direction in which the plurality of nozzles 15 are arrayed. Each third opening 16f has a triangular shape in a bottom view. One side of each triangular-shaped third opening 16f communicates with the second opening 16a, and a vertex opposite to this side is positioned leftward of this side. The third openings 16f have dimensions in the front-rear direction that narrows toward the vertex, i.e., toward the downstream side in the moving direction of the wiper blade 50A.
In the second plate 16B according to the third embodiment, ink or foreign matter separated from the nozzles 15 can be transferred to the third openings 16f and, hence, can be quickly taken out of the second opening 16a. Further, since the dimension in the front-rear direction of each third opening 16f narrow toward the downstream end in the moving direction of the wiper blade 50A, ink is naturally scraped out through the third openings 16f while moving downstream. Note that each third opening 16f need not have a triangular shape, but may have a circular or square shape, for example.
Alternatively, if the wiper blade 50A moves from the left side toward the right side in the printer 1, the open area of the second opening 16a on the right side should be greater than the open area on the left side, and the third openings 16f should be formed so as to communicate with a right end of the second opening 16a, with one on the front end and one on the rear end thereof.
Note that parts and components in the third embodiment having the same structure as those in the first or second embodiment are designated with the same reference numerals to avoid duplicating description.
Next, a second plate 16C in an inkjet head 4 according to a fourth embodiment will be described with reference to
A plurality of first protrusions 31 (an example of a protrusion and a first protruding portion) is provided on the lower surface 16e of the second plate 16C. The first protrusions 31 are disposed between the neighboring second openings 16a, at the right side of the rightmost second opening 16a, and at the left side of the leftmost second opening 16a.
The first protrusions 31 extend in the longitudinal direction of the second openings 16a along the nozzle rows. A pair of first protrusions 31 is arranged with a gap 31a formed therebetween at a position between the neighboring second openings 16a, at the right side of the rightmost second opening 16a, and at the left side of the leftmost second opening 16a.
A plurality of second protrusions 32 (another example of the protrusion) is also provided on the lower surface 16e of the second plate 16C. The two second protrusions 32 are respectively disposed outward of a front end and a rear end of each second opening 16a in the longitudinal direction of the second opening 16a. In other words, each second protrusion 32 is positioned outward of each end portion of the nozzle row in the longitudinal direction of the second opening 16a.
Since the first protrusions 31 extend along the nozzle rows, a single first protrusion 31 can protect multiple nozzles 15, thereby efficiently preventing damage to the nozzles 15.
Airflow along the front-rear direction is produced when the recording sheet 100 is conveyed. Ink ejected from the nozzles 15 may be affected by this airflow, resulting in ink droplets impacting the recording sheet 100 at positions deviating from the target positions. In the printer 1 according to the fourth embodiment, some of this airflow is circulated through the gaps 31a and flows in a direction perpendicular to the front-rear direction. Accordingly, this arrangement can reduce the strength of the air flowing in the front-rear direction.
Further, since the second protrusions 32 are provided at positions outward of the front end and rear end of each second opening 16a, each second protrusion 32 is positioned on the upstream side of the second opening 16a in the conveying direction of the recording sheet 100, regardless of whether the recording sheet 100 is conveyed in the normal direction (frontward direction) or the reverse direction (rearward direction). Hence, even if the recording sheet 100 rises off the platen 3 while being conveyed so that an edge of the recording sheet 100 turns toward the nozzles 15, the edge of the recording sheet 100 will more likely contact the second protrusions 32 than the nozzles 15.
Note that parts and components in the fourth embodiment having the same structure as those in the first to third embodiments are designated with the same reference numerals to avoid duplicating description.
Next, a second plate 16D in an inkjet head 4 according to a fifth embodiment will be described with reference to
In the second plate 16D according to the fifth embodiment, the ends of the first protrusions 531 in the longitudinal direction of the second opening 16a are disposed on the upstream side of the second openings 16a in the conveying direction of the recording sheet 100, regardless of whether the recording sheet 100 is conveyed in the normal direction (frontward direction) or reverse direction (rearward direction). Hence, even if the recording sheet 100 rises off the platen 3 while being conveyed so that the edge of the recording sheet 100 turns toward the nozzles 15, the edge of the recording sheet 100 will more likely contact the ends of the first protrusions 531 than the nozzles 15.
Note that parts and components in the fifth embodiment having the same structure as those in the first to fourth embodiments are designated with the same reference numerals to avoid duplicating description.
Next, a second plate 16E in an inkjet head 4 according to a sixth embodiment will be described with reference to
In
Similarly, a line P2 in
First protrusions 631 (an example of a protrusion) extend in the longitudinal direction of the second opening 16a. The first protrusions 631 are not disposed at positions that overlap the unused regions R1 and R2 in the up-down direction. In other words, portions of the first protrusions 631 that would occupy positions overlapping the unused regions R1 and R2 in the up-down direction have been removed. In
Here, since the nozzles 15 positioned in the unused regions R1 and R2 are unused, the first protrusions 631 are not required for protecting these unused nozzles 15. Therefore, the unnecessary portions of the first protrusions 631 are removed in the sixth embodiment to thereby reduce manufacturing costs.
Note that parts and components in the sixth embodiment having the same structure as those in the first to fifth embodiments are designated with the same reference numerals to avoid duplicating description.
Next, a second plate 16F in an inkjet head 4 according to a seventh embodiment will be described with reference to
A pair of first protrusions 731 (an example of a protrusion, a first protruding portion and a protruding portion) each extending in the longitudinal direction of the second opening 16a is arrayed in the longitudinal direction of the second opening 16a on both the right side and the left side of each second opening 16a. A margin 15e is provided between the nozzle rows 15a and 15b, and the nozzle rows 15c and 15d in each head unit 12. The margins 15e are aligned in the left-right direction (the arraying direction of the liquid ejecting modules 11) with gaps 731a provided between the pairs of first protrusions 731. The margins 15e and the gaps 731a are in communication with each other in the left-right direction.
Since the margins 15e and the gaps 731a communicate with each other in the left-right direction in the seventh embodiment, some of airflow produced by the conveyed recording sheet 100 easily flows in the left-right direction therethrough. As indicated by an arrow DR in
Note that each pair of first protrusions 731 may extend in the front-rear direction (a direction perpendicular to the arraying direction of the liquid ejecting modules 11). Even with this arrangement, the strength of airflow in the conveying direction of the recording sheet 100 can be weakened provided that the margins 15e and the gaps 731a are in communication with each other in the left-right direction.
Note that parts and components in the seventh embodiment having the same structure as those in the first to sixth embodiments are designated with the same reference numerals to avoid duplicating description.
<Variations>
While the description has been made in detail with reference to the embodiments thereof, it would be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the scope of the above-described embodiment. Variations of the embodiments will next be described. The direction in which the nozzle rows are arrayed is not limited to an oblique direction that intersects both the conveying direction of the recording sheet and the arraying direction of the liquid ejecting modules, but may be parallel to the arraying direction of the liquid ejecting modules.
Further, the printer according to the present disclosure is not limited to a line printer, but may be a serial printer that scans a print head in a direction intersecting the conveying direction of the recording sheet. Further, the medium conveyed in the printer is not limited to the recording sheet 100, but may be any recordable media (fabric, for example).
The area of each second opening may be the same as or even smaller than the area of each first opening. Further, the second plate need not be adhesively fixed to the first plates. For example, the second plate may be configured to be movable relative to the first plates and may be configured to contact and be engaged with the first plates during an ejection operation. Further, the protrusions need not be positioned between neighboring head units and neighboring liquid ejecting modules, but may be disposed in positions overlapped with the head units and the liquid ejecting modules.
All embodiments described above are merely examples in all aspects and should not be considered to be limiting. The technical features described in each embodiment may be combined with each other, and the scope of the present disclosure is intended to encompass all modifications within the scope of the claims and a scope equivalent to the scope of the claims.
The present disclosure exemplified in the embodiments, modification and examples described above may be summarized as follows.
(1) According to one aspect, the disclosure provides a liquid ejecting head including: a plurality of liquid ejecting modules each including a plurality of head units and a first plate, a second plate, and a protrusion. The plurality of liquid ejecting modules is arrayed in a first direction. The first plate has a first surface to which the plurality of head units is fixed and a second surface opposite to the first surface. The first plate has a thickness in a second direction. The second plate is disposed at the second surface of the first plate so as to extend along the plurality of liquid ejecting modules. The protrusion protrudes from the second plate in a direction away from the first plate.
(2) In the liquid ejecting head according to the aspect (1), it is preferable that: each of the plurality of head units includes a plurality of nozzles; the first plate is formed with a plurality of first openings each overlapped with the plurality of nozzles in the second direction; and the second plate is formed with a plurality of second openings each overlapped with each of the plurality of first openings in the second direction.
(3) In the liquid ejecting head according to the aspect (2), preferably, an outline of each of the plurality of first openings and an outline of each of the plurality of second openings are overlapped with each of the plurality of head units in the second direction.
(4) In the liquid ejecting head according to the aspect (2), preferably, when viewed in the second direction, each of the plurality of second openings has an area greater than an area of each of the plurality of first openings.
(5) In the liquid ejecting head according to any one of the aspects (2) to (4), it is preferable that: each of the plurality of second openings has a central axis extending in the second direction; each of the plurality of first openings has a central axis extending in the second direction; and the central axis of each of the plurality of second openings is offset from the central axis of each of the plurality of first openings in the first direction.
(6) In the liquid ejecting head according to any one of the aspects (2) to (5), it is preferable that: each of the plurality of second openings has one end in the first direction; and the second plate is formed with a third opening in communication with the one end in the first direction of each of the plurality of second openings.
(7) In the liquid ejecting head according to the aspect (6), it is preferable that: the one end in the first direction of each of the plurality of second openings has end portions in an arraying direction of the plurality of nozzles; and the third opening is formed at each end portion of the one end of each of the plurality of second openings in the arraying direction of the plurality of nozzles.
(8) In the liquid ejecting head according to any one of the aspects (1) to (7), it is preferable that: neighboring head units of the plurality of head units provide a first gap therebetween in the first direction; and the protrusion is overlapped with the first gap in the second direction.
(9) In the liquid ejecting head according to any one of the aspects (1) to (7), it is preferable that: neighboring liquid ejecting modules of the plurality of liquid ejecting modules provide a second gap therebetween in the first direction; and the protrusion is overlapped with the second gap in the second direction.
(10) In the liquid ejecting head according to the aspect (1), it is preferable that: each of the plurality of head units includes a plurality of nozzles arrayed in a predetermined direction to form a nozzle row; and the protrusion includes a first protrusion extending in the predetermined direction along the nozzle row.
(11) In the liquid ejecting head according to the aspect (10), preferably, the first protrusion has an end portion in the predetermined direction positioned outward of an end portion in the predetermined direction of each of the plurality of head units.
(12) In the liquid ejecting head according to the aspect (10) or (11), preferably, the protrusion further includes a second protrusion positioned outward of an end portion in the predetermined direction of the nozzle row.
(13) In the liquid ejecting head according to any one of the aspects (10) to (12), it is preferable that: the first protrusion includes a plurality of first protruding portions spaced away from each other in the predetermined direction.
(14) In the liquid ejecting head according to any one of the aspects (10) to (12), it is preferable that: the first protrusion includes a plurality of protruding portions arrayed in the predetermined direction, neighboring protruding portions of the plurality of protruding portions providing a gap therebetween; and the nozzle row of each of the plurality of head units includes a plurality of nozzle rows arrayed in the predetermined direction, neighboring nozzle rows of the plurality of nozzle rows providing a margin therebetween, the margin and the gap being aligned in the first direction.
(15) In the liquid ejecting head according to the aspect (14), preferably, each of the plurality of protruding portions extends in a direction perpendicular to the first direction.
(16) In the liquid ejecting head according to any one of the aspects (10) to (14), preferably, the predetermined direction is not coincident with the first direction and a direction perpendicular to the first direction.
(17) In the liquid ejecting head according to the aspect (1), it is preferable that: each of the plurality of head units includes a plurality of nozzles; each of the plurality of liquid ejecting modules has a used region in which the plurality of nozzles is used and an unused region in which the plurality of nozzles is unused; and the protrusion is exclusively disposed at a position overlapped with the used region in the second direction.
(18) In the liquid ejecting head according to the aspect (17), it is preferable that: each of the plurality of liquid ejecting modules includes one nozzle row including the plurality of nozzles and another nozzle row including the plurality of nozzles and positioned adjacent to the one nozzle row; and a nozzle of the one nozzle row is out of alignment with a nozzle of the another nozzle row in a direction perpendicular to the first direction with respect to the unused region.
(19) In the liquid ejecting head according to the aspect (17) or (18), it is preferable that: each of the plurality of liquid ejecting modules has end portions in the first direction; and the unused region constitutes each end portion in the first direction of each of the plurality of liquid ejecting modules.
According to the present disclosure, since the protrusion protruding toward the direction away from the first plate is provided at the second plate, a predetermined distance is provided between a recording medium and openings formed in the second plate. Accordingly, the protrusion can prevent the recording medium from entering the openings, thereby suppressing damage to the nozzles. Further, since the second plate closes gaps defined between the neighboring first plates, ink can be prevented from collecting in these gaps.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2017-065672 | Mar 2017 | JP | national |
This is a by-pass continuation application of International Application No. PCT/JP2018/010530 filed Mar. 16, 2018 claiming priority from Japanese Patent Application No. 2017-065672 filed Mar. 29, 2017. The entire contents of the International Application and the priority application are incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/JP2018/010530 | Mar 2018 | US |
| Child | 16551068 | US |
