JP2003326706A - Ink jet head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ink jet head of an ink jet recorder arranged such that a bubble is prevented from standing in an internal ink channel and a standing bubble, if any, can be discharged readily. <P>SOLUTION: The ink jet head 6 has the ink channel extending from a common ink chamber 7 to a nozzle 35 through a pressure chamber 36. The pressure chamber 36 elongated in the flowing direction of ink and an ink supply hole 38 located on the upstream side of the pressure chamber 36 and being connected to one end side thereof in the longitudinal direction are formed as a part of the ink channel. The part of the ink supply hole 38 being connected with the pressure chamber 36 guides ink, with an inclination angle, from the side in the pressure chamber 36 substantially opposite to the flowing direction of ink toward the end part wall 36c on one end side of the pressure chamber 36 in the longitudinal direction. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet head of an ink jet type recording apparatus for ejecting an ink liquid from a nozzle to perform required recording on recording paper or the like.

[0002]

2. Description of the Related Art Conventionally, the structure is relatively simple and high-speed printing
An inkjet type recording apparatus is well known as a recording apparatus that can easily perform high-quality printing. As an ink jet head of a conventional ink jet type recording apparatus, for example, a plurality of nozzles for ejecting ink to a printing surface, pressure chambers provided corresponding to each of the nozzles, and ink are distributed to the pressure chambers. Some have a common ink chamber for supply. In this configuration, first, the ink is supplied to the common ink chamber, and the ink is distributed to the pressure chambers via the ink supply holes. Then, the distributed ink is pressurized in each pressure chamber, passes through the through hole, and is ejected from the nozzle. In this way, an ink flow path from the common ink chamber to the nozzle via the pressure chamber is formed.

[0003]

However, in the above-mentioned conventional configuration, there may be a portion where the ink does not flow smoothly in the ink flow path from the common ink chamber to the nozzle. For example, as shown in FIG. 11, the first flow path 136
And a portion where the second flow path 138 and the second flow path 138 are connected while being substantially orthogonal to each other. In this configuration, the ink flows through the second flow path 138.
Flow toward the first flow path 136 from the (ink flow A2
→ A1), when the end of the second flow path 138 does not overlap the end wall 136c of the first flow path 136 and is connected to the first flow path 136 on the inner side, the end wall 136c Second flow path 138
A portion where the ink stagnates is formed at the step portion 136d between the end opening of the ink.

Then, even if the ink is sucked from the nozzle side as shown by the arrow A2 → A1 by an appropriate purging mechanism attached to the apparatus side, the air bubbles in the stepped portion 136d are sucked out and removed. Becomes considerably difficult. That is, even if the purging mechanism cannot completely remove the air in the step portion 136d at the time of initial introduction of the ink, or the bubbles generated in the ink during the printing operation gather and grow in the step portion 136d, the purging mechanism is generated. It may not be possible to remove these bubbles. As a result, during the printing operation, the bubbles in the step portion 136d grow large and obstruct the flow of ink, and it becomes impossible to eject the ink from the nozzles, resulting in a blank (dot omission) on the printing surface. There's a problem.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an ink jet head in which bubbles are unlikely to be accumulated in an ink flow path, and even if they are accumulated, a purge mechanism can easily suck the bubbles. It is a thing.

[0006]

The problems to be solved by the present invention are as described above, and the means for solving the problems will be described below.

According to the first aspect of the present invention, a plurality of nozzles for ejecting ink to the printing surface, pressure chambers provided corresponding to the respective nozzles, and a common chamber for distributing and supplying ink to the pressure chambers are provided. An inkjet head having an ink chamber and an ink flow path extending from a common ink chamber to the nozzle via the pressure chamber, the first head being part of the ink flow path and long in the ink flow direction. A flow path and a second flow path, which is located upstream of the first flow path and forms a part of the ink flow path, and which is connected to one longitudinal end of the first flow path, A portion where the second flow path is connected to the first flow path has an end portion on one end side in the longitudinal direction of the first flow path with an inclination angle from a side substantially opposite to a flow direction of ink in the first flow path. Characterized by guiding ink in the direction toward the wall There.

According to the above construction, the ink in the second flow passage is usually formed at the connecting portion between the end wall of the first flow passage and the second flow passage, in which stagnation occurs in the ink flow and bubbles tend to accumulate. Flow toward the end wall of the first flow path. Therefore, the bubbles in the space can be easily washed away and discharged, and the bubble purging characteristics are improved.

In claim 2, in claim 1,
The flat plate that constitutes the inkjet head includes at least a first flat plate and a second flat plate that are stacked adjacent to each other, and the first flat plate has the first flow path having a longitudinal direction parallel to the flat plate. The second flow path is formed in the second flat plate, and the opening formed by the second flow path on the surface of the second flat plate on the first flat plate side is the first flow path. The plate is laminated so as not to overlap the end wall on the one end side in the longitudinal direction so as to overlap with the end wall, and the direction of the second flow path approaches the end wall of the first flow path as it goes downstream. The feature is that the direction is inclined from the direction.

According to the above construction, even if there is a step in the longitudinal direction of the first flow path between the end wall of the first flat plate and the opening of the second flat plate, the bubbles in this step portion are washed away. Can be discharged.

A third aspect of the present invention is characterized in that, in the first or second aspect, the second flow passage is shaped so that a cross-sectional area of the flow passage decreases as it approaches the first flow passage.

According to the above structure, since the momentum of the ink flow ejected from the end of the second flow path to the first flow path can be increased, the bubbles can be more efficiently swept and discharged, and the purging of the bubbles can be performed. The characteristics are further improved.

According to a fourth aspect of the present invention, in any one of the first to third aspects, the first flow path is the pressure chamber, and the second flow path connects the common ink chamber to the pressure chamber. It is characterized in that it is a flow path for

According to the above construction, in the portion where the ink is supplied to the pressure chamber, the bubbles in the space can be flushed out and discharged, and the bubble purging characteristics are good.

[0015]

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a perspective view showing an embodiment of a color inkjet printer as an inkjet recording apparatus of the present invention.

In FIG. 1, the printer head 63 of the color ink jet printer 100 is arranged for each color in order to eject four color inks (for example, cyan, magenta, yellow and black) on the body frame 68 thereof. A total of four piezoelectric inkjet heads 6 are fixed, and a total of four ink cartridges 61 filled with color inks are detachably attached to the main body frame 68. This body frame 6
8 is fixed to a carriage 64 which is reciprocally driven in a linear direction by a drive mechanism 65. The platen roller 66 for feeding the paper is arranged such that its axis extends along the reciprocating direction of the carriage 64, and faces the inkjet head 6.

The carriage 64 has a guide shaft 71 and a guide plate 7 which are arranged in parallel with the support shaft of the platen roller 66.
It is slidably supported by 2. Pulleys 73 and 74 are supported near both ends of the guide shaft 71, and an endless belt 75 is stretched between these pulleys 73 and 74. The carriage 64 is fixed to the endless belt 75. In such a structure of the drive mechanism 65, when one pulley 73 is rotated in the forward and reverse directions by the drive of the motor 76, the carriage 64 is reciprocally driven linearly along the guide shaft 71 and the guide plate 72 accordingly. The printer head 63 is reciprocated.

The paper 62 is the ink jet printer 10.
Paper is fed from a paper feed cassette (not shown) provided on the side of 0, and the inkjet head 6 and the platen roller 66 are fed.
The ink is ejected from the ink jet head 6 after being printed in a predetermined space by being guided to a space between the paper and the paper. In FIG. 1, the paper feed mechanism and the paper discharge mechanism for the paper 62 are not shown.

The purging mechanism 67 is for forcibly sucking and removing defective ink containing air bubbles, dust, etc. accumulated inside the ink jet head 6. The purge mechanism 67 is provided on the side of the platen roller 66, and the purge mechanism 67 is disposed so as to face the inkjet head 6 when the printer head 63 reaches the reset position by the drive mechanism 65 described above. It is set. The purging mechanism 67 includes a purge cap 81.
And is in contact with the lower surface of the inkjet head 6 so as to cover a large number of nozzles (details will be described later) provided on the lower surface of the inkjet head 6. With this configuration, when the printer head 63 is at the reset position,
The nozzle of the inkjet head 6 provided on the carriage 64 is covered with a purge cap 81, and defective ink containing bubbles and the like accumulated inside the inkjet head 6 is sucked by a pump 82 by driving a cam 83 to waste ink. The inkjet head 6 is restored by discarding it in the reservoir 84. Thereby, the bubbles can be removed at the time of the initial introduction of the ink to the inkjet head 6, or the inkjet head 6 can be returned to the normal state from the ejection failure state that has been caused by the growth of the internal bubbles accompanying the printing. The cap 85 shown in FIG. 1 is for covering a large number of nozzles of the inkjet head 6 on the carriage 64, which is returned to the reset position after printing is completed, to prevent the ink from drying.

FIG. 2 is a perspective view of the printer head 63 which is turned upside down. As shown in the figure, the main body frame 68 of the printer head 63 is formed in a substantially box-like shape with its upper surface side (shown as being located on the lower surface side in FIG. 2) opened, and its opening The four ink cartridges 61 are detachably mountable from the side where they are mounted to form a mounting portion. As shown in FIG. 2, at one side portion of the mounting portion of the main body frame 68, the ink supply passages 4, 4, 4, 4 that can be connected to the ink discharge portion of each ink cartridge 61 are provided on the bottom plate 5 of the main body frame 68.
Bottom surface (surface on which the inkjet head 6 is fixed)
It communicates with. The ink supply holes 39 of the ink jet head 6 are associated with the respective ink supply passages 4.
A joint member 47 made of rubber or the like that can be brought into close contact with (described later) is attached to the lower surface of the bottom plate 5.

As shown in FIG. 2, on the lower surface side of the bottom plate 5,
Four supporting portions 8 for arranging four inkjet heads 6 in parallel are formed in a stepped shape. The inkjet head 6 is fixed to each of the supporting portions 8 with an ultraviolet curable adhesive.

A perspective view of the ink jet head 6 is shown in FIG. The inkjet head 6 has a laminated cavity plate 10, and a plate type piezoelectric actuator (hereinafter referred to as “actuator”) 20 is bonded and laminated to the cavity plate 10 through an adhesive or an adhesive sheet. It And further actuator 2
On the upper surface of 0, a flexible flat cable 40 for electrical connection with an external device is superposed and bonded with an adhesive. A large number of nozzles 35 are opened on the lower surface side of the lowermost cavity plate 10, and ink is ejected downward from each nozzle 35.

FIG. 4 is an exploded perspective view of the cavity plate 10, and FIG. 5 is an exploded enlarged perspective view of the cavity plate 10 (cross section taken along line VV in FIG. 4). As shown in FIGS. 4 and 5, the cavity plate 10 includes a nozzle plate 11, a damper plate 12, two manifold plates 13X and 13Y, and three spacer plates 14X.
A total of eight thin metal plates of 14Y and 14Z and the base plate 15 are laminated and bonded with an adhesive to form a structure.

As shown in FIGS. 4 and 5, a large number of ink jet nozzles 35 having a minute diameter (about 25 μm in the present embodiment) are formed at minute intervals on the nozzle plate 11. This nozzle 35 corresponds to the nozzle plate 11
Are arranged in two staggered rows along the longitudinal direction.

As shown in FIG. 5, a plurality of pressure chambers 36, 36 ... Are formed in the base plate 15 in two rows in a staggered arrangement along the longitudinal direction of the base plate 15. The specific shape of the pressure chamber 36 is shown in FIG.
As shown in this figure, each pressure chamber 36 is formed in a narrow width such that its longitudinal direction is orthogonal to the longitudinal direction of the base plate 15.

The other end 36a of each pressure chamber 36 is also formed in the three spacer plates 14X, 14Y, 14Z, the two manifold plates 13X, 13Y, and the damper plate 12 in a staggered arrangement. It communicates with the above-mentioned nozzle 35 in the nozzle plate 11 through a small-diameter through hole 37.

The upper spacer plate 14X adjacent to the base plate 15 is provided with an ink supply hole 38 at a position corresponding to each pressure chamber 36.
Is connected to one end 36 b of each pressure chamber 36. On the intermediate spacer plate 14Y located immediately below, an elongated narrowed portion 43 is formed in a penetrating manner in parallel with the longitudinal direction of the pressure chamber 36. The ink supply hole 38 is provided in the throttle portion 4.
3 is connected to one end. The other end of the narrowed portion 43 communicates with a common ink chamber 7, which will be described later, through an introduction hole 44 that is provided to penetrate the lower spacer plate 14Z. The throttle unit 43 plays a role of effectively ejecting the ink from the nozzle 35 by limiting the fluctuation of the ink pressure generated by the operation of the actuator 20 described later toward the ink supply hole 38 side.

As shown in FIG. 5, of the two manifold plates (13X and 13Y), the spacer plate 14
Upper side manifold plate 13X closer to X-14Z
The two ink chamber half portions 13a, 13a are formed in a penetrating manner. On the other hand, on the lower manifold plate 13Y located on the nozzle plate 11 side, two ink chamber half portions 13b and 13b are provided on the upper manifold plate 13X.
It is recessed so that it opens only toward. With this configuration, by stacking a total of three manifold plates 13X and 13Y and the lower spacer plate 14Z, the corresponding upper and lower ink chamber halves 13a and 13b are joined to each other to form the through hole 37. Two common ink chambers 7 are formed, one on each side of the row, as shown in FIG.

The two common ink chambers 7 are provided on both sides of the row of the through holes 37 in order to correspond to the pressure chambers 36 arranged in two rows. That is, the pressure chamber group on the one row side of the two rows arranged is communicated with one common ink chamber 7, and the pressure chamber group on the other one row side is communicated with the other common ink chamber 7. By configuring the inkjet head 6 in this way, two common ink chambers 7
It is also possible to supply inks of different colors to each other and to use it in a printing form in which one ink jet head 6 performs two-color printing, thereby increasing versatility of the ink jet head 6 and reducing the number of parts. There is. However, in the present embodiment, the same color ink is supplied to both common ink chambers 7 and 7, and the printing form in which the two rows of nozzles 35 perform high-resolution printing of a single color is adopted.

As shown in FIG. 5, the damper plate 12 located immediately below the manifold plates 13X and 13Y.
Damper grooves 12c and 12c are provided in the recess. The damper grooves 12c, 12c are formed so as to open only toward the manifold plate 13Y side, and their positions and shapes are made to coincide with those of the common ink chambers 7, 7. Therefore, when the manifold plates 13X and 13Y and the damper plate 12 are joined together, the damper groove 12c is located in the recessed portion (damper portion 42) of the ink chamber half portion 13b of the manifold plate 13Y. Here, since the manifold plate 13Y is made of a metal material (for example, stainless steel) that can be appropriately elastically deformed,
The damper portion 42 can freely vibrate on both the common ink chamber 7 side and the damper groove 12c side. With the above configuration, even if the pressure fluctuation generated in the pressure chamber 36 at the time of ink ejection propagates to the common ink chamber 7, the damper section 42 is elastically deformed and vibrates to absorb and attenuate the pressure fluctuation. (Damper action) It is possible to prevent crosstalk in which pressure fluctuation propagates to another pressure chamber 36.

As shown in FIG. 4, two ink supply holes 39a and 39a are formed in the base plate 15, and two ink supply holes 39b to 39d are similarly formed in the spacer plates 14X, 14Y and 14Z. Has been done. Base plate 15 and spacer plate 14X / 1
By joining 4Y and 14Z, the corresponding ink supply holes 39a to 39d are connected to each other, and the ink supply holes 39 respectively corresponding to the two common ink chambers 7 and 7 described above.
・ 39 is formed. Due to the demand for miniaturization of the ink jet head 6, the ink supply holes 39, 39 are formed near the end of the row formed by the plurality of pressure chambers 36, ... 39 and 39 are arranged close to each other.

With the configuration of the cavity plate 10 as described above, the common ink chamber 7 is connected to the above-mentioned ink supply holes 39.
Ink that has flowed into the inside 7 is introduced from the introduction hole 44 to the throttle 4
3, the ink is supplied from the one end 36b side of each pressure chamber 36 via the ink supply hole 38. Then, the ink, to which the ejection energy is applied by the actuator 20 described later in each pressure chamber 36, is ejected to the corresponding nozzle 35 after passing through the through holes 37, ... From the other end portion 36a. . As described above, the ink is supplied to the inkjet head 6 through the common ink chamber 7 and the introduction hole 4.
4, an ink passage that passes through the throttle portion 43, the ink supply hole 38, the pressure chamber 36, and the nozzle 35 in this order is formed.

FIG. 7 is an exploded enlarged perspective view of the actuator 20. The actuator 20 is shown in FIGS.
As shown in (2), it has a structure in which two types of piezoelectric sheets 21 and 22 and one insulating sheet 23 are laminated. On the upper surface of one piezoelectric sheet 21, a plurality of drive electrodes 24 having a narrow width corresponding to each pressure chamber 36 in the cavity plate 10.
Are arranged in a staggered arrangement. One end 24a of each drive electrode 24 is connected to the front and back surfaces 20a of the actuator 20.
It is formed so as to be exposed on the left and right side surfaces orthogonal to 0b.

On the upper surface of the other piezoelectric sheet 22, a common electrode 25 common to a plurality of pressure chambers 36 is provided. The one end portion 25a of the common electrode 25 is also formed so as to be exposed on the left and right side surfaces, similarly to the one end portion 24a of each drive electrode 24. The piezoelectric sheets 21 and 22 are laminated one by one as shown in the figure, or a plurality of layers are alternately laminated and sandwiched between the drive electrodes 24 and the common electrode 25.
The respective regions in 1.22 are pressure generating portions corresponding to the respective pressure chambers 36.

On the upper surface of the uppermost insulating sheet 23, a surface electrode 26 for each drive electrode 24 and a surface electrode 27 for the common electrode 25 are provided side by side along the left and right side surfaces.

Further, on the left and right side surfaces, a first groove 30 is formed at one end 24a of each drive electrode 24, and a second groove 31 is formed at one end 25a of the common electrode 25 so as to extend in the stacking direction. It is provided. Side electrodes (not shown) that electrically connect the drive electrodes 24 and the surface electrodes 26 are provided in the first recessed grooves 30, and the common electrodes 25 are provided in the second recessed grooves 31. Side electrodes (not shown) that electrically connect to the surface electrodes 27 are formed respectively.
Note that the electrodes 28 and 29 are electrodes in a discarded pattern.

Cavity plate 1 having the above structure
0 and the actuator 20 correspond to the cavity plate 10
The pressure chambers 36 and the drive electrodes 24 of the actuator 20 are laminated so as to correspond to each other. Also, on the upper surface 20a of the actuator 20,
Various wiring patterns (not shown) in the flexible flat cable 40 are electrically joined to the surface electrodes 26 and 27.

Then, when a voltage is applied between any of the drive electrodes 24 of the actuator 20 of the ink jet head 6 and the common electrode 25,
In the piezoelectric sheet 22, a portion of the drive electrode 24 to which a voltage is applied (that is, a pressure generating portion) is distorted in the stacking direction due to the piezoelectric, and the volume of the pressure chamber 36 is reduced. In this way, the ejection energy is applied to the ink in the pressure chamber 36, and the ink is ejected in the form of droplets from the nozzle 35, so that the predetermined printing is performed on the paper 62.

As described above, in the head unit (inkjet head) 6 of this embodiment, due to the structure of the cavity plate 10, the ink flows into the common ink chamber 7 from the above-mentioned ink supply holes 39. The ink is supplied from the introduction hole 44, the throttle portion 43, and the ink supply hole 38 from the one end portion 36b side of each pressure chamber 36. Then, the ink given the ejection energy by the actuator 20 in each pressure chamber 36 is
After passing through the through holes 37, 37 ... From the other end portion 36a, the corresponding nozzle 35 is jetted. In this way, in the ink jet head 6, the ink is supplied with the common ink chamber 7, the introduction hole 44, the narrowed portion 43, and the ink supply hole 3.
8, an ink flow path is formed which passes through the pressure chamber 36 and the nozzle 35 in this order.

Here, in the ink flow path described above, as described above, the ink flow smoothly without causing stagnation, bubbles are less likely to be accumulated in the ink, and even if they are accumulated, the purge mechanism 67 facilitates the accumulation. It is required that it can be sucked out and removed. This is because the bubbles cannot be completely removed at the time of initial introduction of the ink, or if bubbles are generated and grow in the ink during the printing operation, ejection failure occurs in the ejection of the ink from the nozzle 35. This is because it causes a blank (dot missing) on the printed surface.

Regarding this point in the present embodiment, FIG.
As shown in FIG. 3, at the location where the ink supply hole (second flow path) 38 is connected to the pressure chamber (first flow path), an opening 38 a formed by the ink supply hole 38 facing the pressure chamber 36, Since it is located inward so as not to overlap the end wall 36c of the pressure chamber 36, a stepped portion 36d is consequently formed. However, since the ink supply hole 38 is tilted from the flat plate stacking direction so as to approach the end wall 36c toward the downstream side, the ink immediately after being introduced into the pressure chamber 36 is the end wall 36c. Flowing toward. In this way, since the ink flow is formed toward the end wall 36c via the step portion 36d, stagnation does not occur at the step portion 36d. In other words, in the present embodiment, as shown in FIG. 9, the second ink flow A2 supplied to the pressure chamber 36 from the opening 38a is the pressure chamber 36.
The ink is guided in a direction toward the end wall 36c of the one end 36b in the longitudinal direction of the first ink flow A1 from a side substantially opposite to the flow direction of the ink inside. Therefore, the ink does not settle in the step portion 36d, and even if air bubbles accumulate in the step portion 36d, the purge mechanism 67 can easily flush and discharge the air bubbles in this portion.

In this embodiment, the pressure chamber (first flow path) 36 is formed in the base plate (first flat plate) 15 so as to have a longitudinal direction parallel to the plate 15,
The case where the ink supply holes (second flow paths) 38 are formed in the upper spacer plate (second flat plate) 14X has been described, but the present invention is not limited to this. That is, even if the second flow path is provided in the same member as the first flow path, as long as the ink flows A1 and A2 are formed as shown in FIG. The effect is not impaired.

However, as in this embodiment, two flat plates 1 are used.
In the configuration in which the flow paths 36 and 38 are formed on the 5X and 14X, respectively, and then the flow paths 36 and 38 are stacked, the ink supply holes 38 are formed in order to allow a slight misalignment between the stacked flat plates.
The opening 38a whose end is formed on the pressure chamber 36 side is often located inward with some margin from the end wall 36c of the pressure chamber 36, as shown in FIG. The step portion 36d eventually means this margin portion, but with the configuration of the present invention, stagnation of the ink flow at the step portion 36d does not occur. Therefore, it can be said that the present invention is particularly suitable for a configuration in which two flow paths are connected by stacking two flat plates.

Further, in the present embodiment, the ink supply hole (second flow path) 38 has a uniform flow path cross-sectional area in the flow direction, but as shown in FIG.
The ink supply hole 38 ′ may have a shape (a tapered shape) in which the flow path cross-sectional area decreases as it approaches the base plate (first flat plate) 15. As a result, the second ink flow A
2 can increase the force of the flow ejected from the opening 38a 'to the pressure chamber (first flow path) 36. Therefore, the step portion 3
The bubbles of 6d can be flushed and discharged more efficiently, and the purging characteristics of the bubbles are further improved.

[0045]

According to the present invention, as described above, claim 1
According to the invention described above, the ink in the second flow passage is normally flowed at the connecting portion between the end wall of the first flow passage and the second flow passage, in which stagnation occurs in the ink flow and bubbles are easily accumulated. It flows toward the end wall of the road. Therefore, no stagnation occurs in the portion near the end wall, bubbles in the portion can be easily washed away and discharged, and the bubble purging characteristics are good.

According to the second aspect of the invention, even if there is a step in the longitudinal direction of the first flow path between the end wall of the first flat plate and the opening of the second flat plate, the bubbles in this step portion It can be easily washed away and discharged.

According to the third aspect of the present invention, since the momentum of the ink flow ejected from the end of the second flow path to the first flow path can be increased, the bubbles can be more efficiently swept and discharged. The purging characteristics of are further improved.

According to the fourth aspect of the invention, in the portion where the ink is supplied to the pressure chamber, the bubbles in the space can be flushed and discharged, and the bubble purging characteristics are good.

[Brief description of drawings]

FIG. 1 is a perspective view showing a color inkjet printer according to an embodiment of the present invention.

FIG. 2 is a sectional view of a printer head.

FIG. 3 is an exploded perspective view of a head unit.

FIG. 4 is an exploded perspective view showing a laminated structure of a cavity plate.

5 is an enlarged perspective view taken along line VV in FIG.

6 is an enlarged cross-sectional view taken along line VI-VI in FIG.

FIG. 7 is an exploded perspective view showing a laminated structure of the actuator.

FIG. 8 is an enlarged cross-sectional view of the vicinity of a pressure chamber and an ink supply hole.

FIG. 9 is an enlarged plan view of the vicinity of a pressure chamber and an ink supply hole.

FIG. 10 is an enlarged cross-sectional view of the vicinity of a pressure chamber and an ink supply hole of another embodiment.

FIG. 11 is an enlarged cross-sectional view of a connection portion between a first flow path and a second flow path of a conventional inkjet head.

[Explanation of symbols]

6 inkjet head 7 common ink chamber 35 nozzles 36 Pressure chamber (first flow path) 36c end wall 38 ink supply hole (second flow path)

Claims (4)

[Claims] 1. A plurality of nozzles for ejecting ink onto a printing surface, pressure chambers provided corresponding to the respective nozzles, and a common ink chamber for distributing and supplying ink to the pressure chambers. An ink jet head having an ink flow path from a common ink chamber to the nozzle via the pressure chamber, the first flow path forming a part of the ink flow path and long in a flow direction of ink, A second flow path is formed upstream of the first flow path, forming a part of the ink flow path and connected to one end side in the longitudinal direction of the first flow path. The portion where the passage is connected to the first flow passage is a direction toward the end wall on the one longitudinal end side of the first flow passage with an inclination angle from the side substantially opposite to the ink flow direction in the first flow passage. Inkjet that is characterized by guiding the ink to head. 2. The flat plate forming the inkjet head includes at least a first flat plate and a second flat plate that are stacked adjacent to each other, and the first flow path is parallel to the flat plate in the first flat plate. The second flow path is formed in the second flat plate, and the opening formed by the second flow path is formed on the surface of the second flat plate on the first flat plate side. The first flow path is positioned inward so as not to overlap the end wall on the one end side in the longitudinal direction, and the direction of the second flow path approaches the end wall of the first flow path as it goes downstream. The inkjet head according to claim 1, wherein the inkjet head is tilted from the flat plate stacking direction. 3. The ink jet head according to claim 1, wherein the second flow path has a shape in which a cross-sectional area of the flow path decreases as it approaches the first flow path. 4. The first flow path is the pressure chamber, and the second flow path is a flow path for connecting the common ink chamber to the pressure chamber. The inkjet head according to any one of 3 above.