JP2021098343A - Liquid jet head and liquid jet recording device - Google Patents

Abstract

To provide a liquid jet head which can achieve improvement of position accuracy of an ink discharge groove and an air bubble discharge port, and to provide a liquid jet recording device.SOLUTION: A liquid jet head includes: a discharge part 50 formed with channels 57, 58 which are filled with a liquid to be jetted; and a nozzle plate 32 adhering to the discharge part. The nozzle plate includes a nozzle array 34 formed by arranging nozzle holes 240 in a line. The nozzle holes 240 communicate with a channel of the discharge part. The nozzle array includes air bubble discharge nozzle holes 241. The air bubble discharge nozzle holes are disposed perpendicular to an extension direction of the nozzle array.SELECTED DRAWING: Figure 9

Description

The present invention relates to a liquid injection head and a liquid injection recording device.

Conventionally, there is an inkjet printer provided with an inkjet head as a device for ejecting droplet-shaped ink onto a recording medium such as recording paper and recording an image or characters on the recording medium.

In the inkjet head of the prior art, for example, like the inkjet head described in Patent Document 1 and the like, ink supplied from an ink supply source is applied to each nozzle hole on a substantially extension line in the arrangement direction of the nozzle holes in the nozzle row. At least two exhaust ports for discharging air bubbles are provided at a portion corresponding to the most downstream side in the ink flow direction in a common ink chamber formed long along the nozzle row for distribution, and at least two exhaust ports are provided. The ports are connected to the most downstream portion of the common ink chamber via the same exhaust flow path, and the opening area of each exhaust port is substantially equal to or less than the opening area of each nozzle. Inkjet heads that are formed and have a flow path resistance of an exhaust flow path including two or more exhaust ports lower than the flow path resistance of an ink flow path including a nozzle hole are known.

JP-A-2007-125807

As in the invention described in Patent Document 1, in a structure having an exhaust port on the surface where the nozzle hole opens, it is desired to improve the efficiency of discharging air bubbles from the exhaust port. However, in recent years, the surface area of the entire inkjet head has become smaller due to the overall miniaturization and higher recording density, while the number of nozzle holes and the number of nozzle rows have increased, so that it is used for image recording. The space between rows of nozzle holes tends to be narrow. In the above-mentioned Patent Document 1, a plurality of exhaust ports for discharging air bubbles are provided, and the opening area of each of the exhaust ports is formed to be substantially equal to or smaller than the opening area of each nozzle hole. When the shape of the ink discharge groove and the shape of the exhaust port for discharging air bubbles are the same as in the invention described in Patent Document 1, if a plurality of exhaust ports for discharging air bubbles are provided on the extension line of the nozzle row, the ink discharge groove and exhaust are provided. It is difficult to obtain the position accuracy of the mouth.
Therefore, in the conventional configuration, there is still room for improvement in terms of the positional accuracy of the ink ejection groove and the air bubble exhaust port.
The present invention has been made in consideration of such circumstances, and an object of the present invention is to provide a liquid injection head and a liquid injection recording device capable of improving the positional accuracy of the ink ejection groove and the exhaust port of bubbles. To do.

In order to solve the above problems, the liquid injection head according to one aspect of the present invention includes a discharge portion in which a channel filled with a liquid for injection is formed, and a nozzle plate adhered to the discharge portion. , The nozzle plate includes a nozzle row formed by arranging a plurality of nozzle holes in a row, the nozzle holes communicate with a channel of the discharge portion, and the nozzle row is a plurality of bubble discharge nozzle holes. The bubble discharge nozzle holes are arranged perpendicular to the extending direction of the nozzle row.

According to this configuration, the bubble discharge nozzle hole corresponding to the exhaust port described above is arranged perpendicular to the extending direction of the nozzle row formed in the nozzle plate. As a result, when the nozzle plate is adhered, the air bubble discharge property can be improved and the assembly yield can be improved without affecting the positional accuracy of the channel of the discharge portion and the nozzle hole.

According to one aspect of the present invention, when the nozzle plate is adhered, it is possible to improve the discharge property of air bubbles and improve the yield of assembly without affecting the positional accuracy of the channel of the discharge portion and the nozzle hole. it can.

It is a perspective view which shows the structure of the liquid injection recording apparatus in embodiment of this invention. It is a perspective view of the liquid injection head in embodiment of this invention. It is another perspective view which partially see through the liquid injection head in embodiment of this invention. FIG. 5 is an exploded perspective view of a base member and a first jet module in the liquid injection head according to the embodiment of the present invention. It is an exploded perspective view of the 1st jet module in the Example of this invention. It is an exploded perspective view of the discharge part which concerns on embodiment of this invention. FIG. 6 is a cross-sectional view taken along the line VII-VII of FIG. It is a front view of the discharge part in the conventional structure. It is a front view of the discharge part in embodiment of this invention.

Hereinafter, embodiments according to the present invention will be described with reference to the drawings. In the drawings used in the following description, the scale of each member is appropriately changed in order to make each member recognizable.

(Liquid injection recording device)
FIG. 1 is a perspective view showing the configuration of the liquid injection recording device 1. As shown in the figure, the liquid injection recording device 1 includes a pair of conveying means 2 and 3 for conveying a recording medium S such as recording paper, and a liquid injection for injecting an ink (liquid) (not shown) onto the recording medium S. The head 4 includes an ink supply means 5 for supplying ink to the liquid injection head 4, and a scanning means 6 for scanning the liquid injection head 4 in a scanning direction X orthogonal to the transport direction Y of the recording medium S. In the present embodiment, the direction orthogonal to the two directions of the transport direction Y and the scanning direction X is the vertical direction Z.

The pair of transport means 2 and 3 are arranged at intervals in the transport direction Y, one transport means 2 is located on the upstream side of the transport direction Y, and the other transport means 3 is located on the downstream side of the transport direction Y. Is located in. These transport means 2 and 3 are arranged parallel to the grid rollers 2a and 3a extending in the scanning direction X and the grid rollers 2a and 3a, and are recorded between the grid rollers 2a and 3a. Each of the pinch rollers 2b and 3b that sandwiches the medium S and a drive mechanism (not shown) such as a motor that rotates the grid rollers 2a and 3a around their axes are provided. Then, by rotating the grid rollers 2a and 3a of the pair of conveying means 2 and 3, the recording medium S can be conveyed in the direction of the arrow A along the conveying direction Y.

The ink supply means 5 includes an ink tank 10 containing ink and an ink pipe 11 for connecting the ink tank 10 and the liquid injection head 4. In the illustrated example, the ink tank 10 is conveyed by ink tanks 10Y, 10M, 10C, and 10B containing four colors of ink, yellow (Y), magenta (M), cyan (C), and black (B), respectively. They are arranged side by side in the direction Y. The ink pipe 11 is, for example, a flexible hose having flexibility, and is capable of following the operation (movement) of the carriage 16 that supports the liquid injection head 4.

The scanning means 6 includes a pair of guide rails 15 extending in the scanning direction X and arranged in parallel with each other at intervals in the transport direction Y, and a carriage 16 movably arranged along the pair of guide rails 15. A drive mechanism 17 for moving the carriage 16 in the scanning direction X is provided.

The drive mechanism 17 is arranged between the pair of guide rails 15 and is wound between the pair of pulleys 18 arranged at intervals in the scanning direction X and moved in the scanning direction X. An endless belt 19 and a drive motor 20 for rotationally driving one of the pulleys 18 are provided.

The carriage 16 is connected to the endless belt 19, and is movable in the scanning direction X as the endless belt 19 is moved by the rotational drive of one of the pulleys 18. Further, the carriage 16 is mounted with a plurality of liquid injection heads 4 arranged side by side in the scanning direction X. In the illustrated example, four liquid injection heads 4, that are, liquid injection heads 4Y, 4M, 4C, and 4B, which inject yellow (Y), magenta (M), cyan (C), and black (B) inks, respectively. It is installed.

(Liquid injection head)
FIG. 2 is a perspective view of the liquid injection head 4. FIG. 3 is another perspective view of the liquid injection head 4 with a partial perspective. The liquid injection heads 4Y, 4M, 4C, and 4B all have the same configuration except for the color of the supplied ink. Therefore, in the following description, the liquid injection head 4 will be described.
As shown in FIGS. 2 and 3, the liquid injection head 4 of the present embodiment includes jet modules 30A and 30B (see FIG. 3), a damper 31, a nozzle plate 32 (see FIG. 2), a nozzle guard 33, and the like as base members. It is mounted on the 38 and configured.

(Base member)
FIG. 4 is an exploded perspective view of the base member 38 and the first jet module 30A in the liquid injection head 4.
As shown in FIG. 4, the base member 38 is formed in a plate shape with the Z direction as the thickness direction and the X direction as the longitudinal direction. The base member 38 has a base main body 41 that holds the jet modules 30A and 30B, and a carriage fixing portion 42 for fixing the base member 38 to the carriage 16 (see FIG. 1). In this embodiment, the base member 38 is integrally formed of a metal material.

A module accommodating portion (first module accommodating portion 44A and second module accommodating portion 44B) is formed in the base main body portion 41. Two module accommodating portions 44A and 44B are formed side by side in the Y direction corresponding to the jet modules 30A and 30B. The module accommodating portions 44A and 44B penetrate the base main body portion 41 in the Z direction. Corresponding jet modules 30A and 30B can be inserted into the module accommodating portions 44A and 44B, respectively. That is, the jet modules 30A and 30B are held by the base main body 41 in a state of standing upright from the base member 38 in the + Z direction by inserting the end portions in the −Z direction into the module accommodating portions 44A and 44B.

In the base main body portion 41, a partition portion 46 for partitioning between the module accommodating portions 44A and 44B is formed in a portion located between the module accommodating portions 44A and 44B.
A pair of short side portions 45a and 45b of the base main body 41 facing each other in the X direction are formed with protruding walls 47 projecting inward in the X direction. The protruding walls 47 are formed for each of the module accommodating portions 44A and 44B, with the protruding walls 47 facing each other in the X direction as a set.

A first urging member 48 is provided on the first short side portion 45a. The first urging member 48 is provided corresponding to the module accommodating portions 44A and 44B. Each of the first urging members 48 is formed in a leaf spring shape that is interposed between the first short side portion 45a and the jet modules 30A and 30B, respectively. Each of the first urging members 48 urges the jet modules 30A and 30B toward the second short side portion 45b (in the −X direction).

The carriage fixing portion 42 projects from the + Z direction end portion of the base main body portion 41 in the XY plane. The carriage fixing portion 42 is formed with mounting holes and the like for mounting the base member 38 to the carriage 16 (see FIG. 1).

(Jet module)
As shown in FIG. 3, the jet module 30A is formed in a plate shape with the Y direction as the thickness direction. The jet module 30A is configured so that the ink supplied from the ink tank 10 (see FIG. 1) can be ejected toward the recording medium S. The jet module 30A is mounted on the base member 38.

In the liquid injection head 4 of the present embodiment, ink is ejected in one color from each of the jet modules 30A and 30B. The number of jet modules 30A and 30B mounted on the base member 38, the color and type of ink discharged from the jet modules 30A and 30B, and the like can be appropriately changed. In each of the jet modules 30A and 30B, jet modules having the same configuration are mounted on the base member 38 in the Y direction and opposite to each other. Therefore, in the following configuration, the first jet module 30A will be described as an example.

FIG. 5 is an exploded perspective view of the first jet module 30A.
As shown in FIG. 5, the first jet module 30A mainly includes a discharge unit 50 and a first flow path member 51A and a second flow path member 51B that face each other in the Y direction with the discharge unit 50 in between. I have.

(Discharge part)
FIG. 6 is an exploded perspective view of the discharge unit 50.
As shown in FIG. 6, the discharge unit 50 has a first head tip 52A and a second head tip 52B laminated in the + Y direction with respect to the first head tip 52A. Each of the head tips 52A and 52B is a so-called edge shoot type that ejects ink from an end portion in the extending direction (Z direction) of the ejection channel 57, which will be described later.

The first head tip 52A is configured by superimposing the first actuator plate 55 and the first cover plate 56 in the Y direction.

The first actuator plate 55 is a piezoelectric substrate formed of PZT (lead zirconate titanate) or the like. The polarization direction of the first actuator plate 55 is set in one direction along the thickness direction (Y direction). The first actuator plate 55 may be formed by laminating two piezoelectric substrates having different polarization directions in the Y direction (so-called chevron type).

On the first actuator plate 55, a plurality of channels 57, 58 opened on a surface facing the −Y direction (hereinafter, referred to as “surface”) are arranged side by side at intervals in the X direction. Each of the channels 57 and 58 is formed linearly along the Z direction. Each channel 57, 58 is open on the −Z direction end face of the first actuator plate 55. It should be noted that the channels 57 and 58 may extend so as to be inclined with respect to the Z direction.

FIG. 7 is a cross-sectional view taken along the line VII-VII of FIG.
As shown in FIGS. 6 and 7, the plurality of channels 57 and 58 described above are the ejection channel 57 filled with ink and the non-ejection channel 58 not filled with ink. The discharge channels 57 and the non-discharge channels 58 are arranged alternately in the X direction. Each of the channels 57 and 58 is partitioned in the X direction by a drive wall 61 formed of a first actuator plate 55. A drive electrode 59 is formed on the inner surfaces of the channels 57 and 58. The drive electrode 59 is connected to a drive terminal (not shown) formed on the surface of the first actuator plate 55 at the + Z direction end of the first actuator plate 55.
Further, as shown in FIG. 7, the drive electrode 59 is not formed on the inner surface of the channels 57 and 58 in which the bubble discharge nozzle hole 241 described later is arranged.

The first cover plate 56 has a common ink chamber 62 opened on a surface facing the −Y direction (hereinafter referred to as “front surface”) and a plurality of openings on a surface facing the + Y direction (hereinafter referred to as “back surface”). It has a slit 63 and.
The common ink chamber 62 is formed at a position corresponding to the + Z direction end portion of the ejection channel 57 in the Z direction. The common ink chamber 62 is recessed from the surface of the first cover plate 56 in the + Y direction and extends in the X direction. Ink flows into the common ink chamber 62 through the first flow path member 51A (see FIG. 5).
The slit 63 is formed in the common ink chamber 62 at a position facing the ejection channel 57 in the Y direction. The slit 63 communicates the inside of the common ink chamber 62 and the inside of each ejection channel 57 separately. Therefore, the non-ejection channel 58 does not communicate with the common ink chamber 62.

The second head tip 52B is configured by superimposing the second actuator plate 71 and the second cover plate 72 in the Y direction. In the following description, the same configuration as that of the first head chip 52A in the second head chip 52B will be described with the same reference numerals as those of the first head chip 52A.

The second actuator plate 71 is joined to a surface of the first actuator plate 55 facing in the + Y direction (hereinafter, referred to as “back surface”). The discharge channel 57 and the non-discharge channel 58 of the second head tip 52B are arranged with a half pitch deviation from the arrangement pitch of the discharge channel 57 and the non-discharge channel 58 of the first head chip 52A. That is, the discharge channels 57 and the non-discharge channels 58 of the head tips 52A and 52B are arranged in a staggered pattern.

In the discharge unit 50, the region in which the channels 57 and 58 are arranged is set as the discharge region Q1, and a pair of regions located on both sides in the X direction with respect to the discharge region Q1 (regions outside the outermost channels 57 and 58) are paired. The non-discharge region Q2 of. A communication hole 73 (in FIGS. 6 and 7 shows only one communication hole 73) is formed in the non-discharge region Q2 so as to penetrate the discharge portion 50 (each head tip 52A, 52B) in the Y direction. The communication hole 73 penetrates the head tips 52A and 52B (actuator plates 55 and 71 and cover plates 56 and 72) in the Y direction, and communicates the common ink chambers 62 of the head tips 52A and 52B with each other. The number, position, shape, etc. of the communication holes 73 can be changed as appropriate.

(Nozzle plate)
The nozzle plate 32 described above is made of a resin material such as polyimide. The nozzle plate 32 is fixed to the −Z direction end surface of the base main body 41 and the −Z direction end surface of the discharge portion 50 (portions exposed from the module housing portions 44A and 44B) via an adhesive or the like. The nozzle plate 32 collectively covers the discharge portions 50 of the jet modules 30A and 30B from the −Z direction.

As shown in FIGS. 6 and 7, a plurality of nozzle holes 240 penetrating the nozzle plate 32 in the Z direction are formed in a row on the nozzle plate 32. The nozzle holes 240 are separately formed at positions facing the discharge channels 57 of the head tips 52A and 52B in the Z direction.

The ink in the nozzle hole 240 and the bubble discharge nozzle holes 241A and 241B forms an appropriate (concave) meniscus due to the surface tension acting on the inner surfaces of the nozzle hole 240 and the bubble discharge nozzle holes 241A and 241B, respectively. .. That is, in the liquid injection recording device 1 of the present embodiment, the pressure in the discharge channel 57 is maintained at a desired negative pressure due to the head difference between the liquid level of the ink tank 10 and the liquid level of the meniscus. As a result, the above-mentioned meniscus is retained so that the ink does not leak unexpectedly.

The nozzle plate 32 is not limited to the resin material, and may be formed of a metal material (stainless steel or the like), or may have a laminated structure of the resin material and the metal material. In the present embodiment, the configuration in which one nozzle plate 32 covers the jet modules 30A and 30B together has been described, but the present invention is not limited to this configuration, and the jet modules 30A and 30B are individually covered by a plurality of nozzle plates 32. It may be configured to cover with.

As described above, the nozzle plate 32 is fixed to the −Z direction end surface of the base main body 41 and the −Z direction end surface of the discharge portion 50 (portions exposed from the module housing portions 44A and 44B) via an adhesive or the like. ..
In the conventional configuration as shown in FIG. 8, the nozzle plate 32 is formed at the end of the extension line (X direction) of the nozzle row 34 so as to be substantially equal to or smaller than the inner diameter of the nozzle hole 240. The two bubble discharge nozzle holes 241'are arranged.
However, in this configuration, the width dimension of the channels 57 and 58 (in the X direction) is limited in order to increase the density between the channels as the number of nozzles and the number of nozzle rows increase, so that the channel of the discharge portion is used. It becomes difficult to obtain the positional accuracy of 57 and 58 and the nozzle hole 240 in the X direction. Therefore, as shown in FIG. 8, it is necessary to widen the widths of the channels 57 and 58 communicating with the bubble discharge nozzle holes 241'arranged on the extension line of the nozzle row 34. As a result, since it is necessary to form the channels 57 and 58 having different width dimensions on the actuator plates 55 and 71, there is a problem that the manufacture of the actuator plates 55 and 71 becomes complicated.

In the present embodiment, as shown in FIG. 9, in the nozzle plate 32, the bubble discharge nozzle hole 241 is located at the end of the nozzle row 34 (see FIG. 6) and is perpendicular to the extending direction of the nozzle row 34 (Y direction). ), The bubble discharge efficiency can be improved without affecting the position accuracy of the discharge unit channels 57 and 58 and the nozzle hole 240 in the X direction, and the number of nozzles and the nozzle row can be further improved. It is possible to increase the density of numbers. As a result, the yield of assembling the liquid injection head 4 can be improved. Further, unlike the conventional configuration (see FIG. 8), it is not necessary to form the channels 57 and 58 having different width dimensions on the actuator plates 55 and 71, so that the actuator plates 55 and 71 can be easily manufactured.

Further, in the present embodiment, as described above, the drive electrode 59 is not formed on the inner surface of the channels 57 and 58 in which the bubble discharge nozzle hole 241 is arranged. This is because the bubble discharge nozzle hole 241 is a nozzle hole for discharging bubbles contained in the ink, and is not for discharging the ink. The drive electrode 59 may be formed on the inner surface of the channels 57 and 58, but in that case, it is necessary to control the liquid injection head 4 so as not to eject ink from the bubble discharge nozzle hole 241. Therefore, the present embodiment is excellent in that the control of the liquid injection head 4 can be facilitated by not forming the drive electrode 59 on the inner surface of the channels 57 and 58.

The inner diameter (opening area) of the bubble discharge nozzle hole 241 of the present embodiment is equivalent to the inner diameter of the nozzle hole 240. However, the inner diameter and the number of each bubble discharge nozzle hole 241 can be changed as appropriate. Further, each bubble discharge nozzle hole 241 is not limited to a round hole.

The technical scope of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, in the above-described embodiment, the inkjet printer 1 has been described as an example of the liquid injection device, but the present invention is not limited to the printer. For example, it may be a fax machine, an on-demand printing machine, or the like.

In the above-described embodiment, the configuration in which two jet modules 30A and 30B are mounted on the base member 38 has been described, but the configuration is not limited to this configuration. The number of jet modules mounted on the base member 38 may be one or a plurality of three or more.

In the above-described embodiment, the head tip of the edge chute has been described, but the present invention is not limited to this. For example, the present invention may be applied to a so-called side shoot type head tip that ejects ink from the central portion of the ejection channel in the extending direction.
Further, the present invention may be applied to a so-called roof chute type head chip in which the direction of pressure applied to ink and the direction of ink ejection are the same.

In the above-described embodiment, the configuration in which the two head chips 52A and 52B are mounted on one jet module has been described, but the configuration is not limited to this configuration. That is, one head chip may be mounted on one jet module.

In addition, it is possible to replace the constituent elements in the above-described embodiments with well-known constituent elements as appropriate without departing from the spirit of the present invention, and the above-mentioned modifications may be appropriately combined.

1 ... Liquid injection recording device 4 ... Liquid injection head 30A ... 1st jet module 30B ... 2nd jet module 32 ... Nozzle plate 34 ... Nozzle row 57, 58 ... Channel 240 ... Nozzle hole 241 ... Bubble discharge nozzle hole

Claims (3)

A discharge part with a channel filled with liquid for injection, and a discharge part
The nozzle plate adhered to the discharge part and
With
The nozzle plate includes a nozzle row formed by arranging a plurality of nozzle holes in a row.
The nozzle hole communicates with the channel of the discharge portion,
The nozzle row includes a plurality of bubble discharge nozzle holes.
A liquid discharge injection head characterized in that the bubble discharge nozzle holes are arranged perpendicular to the extending direction of the nozzle row. The liquid injection head according to claim 1, wherein an electrode for injecting a liquid is formed in the channel of the discharge portion, and the electrode is not formed in the channel in which the bubble discharge nozzle hole is arranged. A liquid injection recording device including the liquid injection head according to claim 1 or 2.

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