JP2003326702A - Ink jet head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ink head capable of dealing readily with high density by saving the space of the channel structure. <P>SOLUTION: The ink jet head comprises a plurality of nozzles 35 ejecting ink, pressure chambers 36 being connected with the nozzles 35, limit channels 43 having one end being connected with one end of the pressure chambers 36, and a common ink chamber 7 being connected with the other end of the pressure chambers 36 and distributing ink to the pressure chambers 36. The head has a laminated plate structure including at least following plates. (1) A first plate P<SB>1</SB>forming the pressure chambers 36, (2) a second plate P<SB>2</SB>forming the common ink chamber 7, and (3) a third plate P<SB>3</SB>interposed between the first plate P<SB>1</SB>and the second plate P<SB>2</SB>to form the limit channels 43. The limit channels 43 are formed in the third plate P<SB>3</SB>to elongate along the plane direction thereof and extend from one end being connected with the pressure chambers 36 in a direction parallel with the plane defined by the plurality of pressure chambers 36. <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 a structure of an inkjet head for forming an image on a print surface by ejecting minute droplets of ink in an inkjet recording apparatus.

[0002]

2. Description of the Related Art An ink jet head provided in an ink jet recording apparatus such as an ink jet printer has a plurality of nozzles for ejecting ink onto a printing surface, and each nozzle is provided and connected to the nozzle. A configuration is known in which a pressure chamber and a common ink chamber for distributing and supplying ink to the pressure chamber are provided inside the inkjet head. The common ink chamber is connected to an unillustrated ink supply source (for example, an ink tank) via an ink supply port provided on the outer surface of the inkjet head. With this configuration, the ink introduced from the ink supply source into the common ink chamber is distributed and supplied to each pressure chamber. The pressure chamber is provided with an actuator composed of, for example, a piezoelectric element, and the ink to which the ejection energy is applied by driving the actuator is ejected from the nozzle to form a desired image on the printing surface.

In order to form these pressure chambers and common ink chambers inside, there is a method of stacking and fixing thin flat plate groups in which the shapes of the pressure chambers, common ink chambers, etc. are formed by etching in advance. Widely adopted.

Further, in order to efficiently direct the pressure generated in the ink in the pressure chamber by driving the actuator to the nozzle side, the construction of an ink jet head having a limiting flow passage for limiting the passage to the common ink chamber is also widely known. Has been.

An example of this structure is shown in FIG. 11, and the ink jet head 6 in FIG. 11 is a cavity formed by laminating six thin metal flat plates (11.12.13X.13Y.14.15). A plate 10 is provided. Inside the cavity plate 10, the common ink chamber 7
Alternatively, the pressure chamber 36 is formed. Reference numeral 35 is a nozzle. In this configuration, the ink introduced into the common ink chamber 7 from the ink supply port (not shown) is supplied to the ink supply hole 38.
To the end portion 36b of the pressure chamber 36, passes through the throttle portion (restricted flow path) 36d, and is guided into the pressure chamber 36.
Then, the ink inside the pressure chamber 36, to which the ink ejection pressure is applied by the driving of the actuator 20, passes through the through hole 37.
To the nozzle 35 and is ejected toward the lower printing surface (not shown).

The restriction flow path 36d is formed in a groove shape by half etching from the lower surface side of the flat plate 15, and the flow path cross-sectional area of the restriction flow path 36d formed is suppressed to be smaller than that of the pressure chamber 36. The flow path resistance for restricting the ink flow that flows back from the chamber 36 to the common ink chamber 7 side is ensured.

[0007]

However, in the conventional ink jet head 6 as shown in FIG. 11, the limiting flow passage 36d is provided on the same flat plate (flat plate 15) as the pressure chamber 36 in the extension direction of the pressure chamber 36. Therefore, the width of (the length of the pressure chamber) + (the length of the restriction flow path) is required in the plane direction of the flat plate. Therefore, there is a problem that it is difficult to meet the demands for downsizing of the inkjet head and high integration in accordance with the needs for higher resolution of images.

Further, the pressure chamber 36 and the restricted flow path 36a are required to have high accuracy in the ink jet head, and to make both of them on the same flat plate 15, both of them must be processed with high accuracy at the same time. The yield is bad,
There was a problem that the cost increased. In addition, other challenges
In order to form the limiting flow path 36a in the same flat plate 15 as the pressure chamber 36, in order to obtain a necessary flow path cross-sectional area, it is formed into a groove shape by half etching, and the depth of this half etching is processed with high accuracy. However, the manufacturing yield is low and the cost is high.

[0009]

The problem to be solved by the present invention is as described above, and the means for solving this problem will be described below.

That is, according to the first aspect, a plurality of nozzles for ejecting ink to the printing surface, pressure chambers provided corresponding to the respective nozzles and connected to the nozzles, and one end of the pressure chambers. An ink jet head having a flat plate laminated structure having a limiting flow path connected to one end thereof and a common ink chamber connected to the other end of the restriction flow path for distributing and supplying ink to the pressure chamber. The flat plate forming the head unit includes: a first flat plate that forms the pressure chamber; a second flat plate that forms the common ink chamber; and a first flat plate that forms the restricted flow path. A third flat plate located between the second flat plate and the third flat plate, and the limiting flow passages are formed in the third flat plate so as to be long along the surface direction thereof, and a plurality of them are provided from one end connected to the pressure chamber. Of the pressure chamber Those extending in the direction parallel to the plane of. As a result, it is possible to arrange the restriction channel in any direction on a plane parallel to the pressure chamber, including a position overlapping the pressure chamber in the stacking direction, and it is possible to make the inkjet head compact and highly integrated. Further, by forming the pressure chamber and the restriction flow path on separate flat plates, it is possible to reduce the cost by eliminating the problem that both must be processed simultaneously with high precision as in the conventional case. These can be easily realized by the following configurations.

According to a second aspect of the present invention, the limiting channel is the third channel.
A connecting flow that is formed through the flat plate and has a fourth flat plate interposed between the third flat plate and the first flat plate to connect the limiting flow path and the pressure chamber to the fourth flat plate. It has a road.

According to a third aspect of the present invention, the first flat plate and the third flat plate are laminated without a flat plate interposed therebetween, and the limiting flow passage is formed in a groove shape on a surface of the third flat plate opposite to the first flat plate. The third flat plate is provided with a connecting flow passage that connects the limiting flow passage and the pressure chamber in a penetrating manner.

According to another aspect of the present invention, the limiting flow path is located between the common ink chamber and the pressure chamber in the stacking direction of the flat plates, and the second flat plate and the third flat plate are stacked without a flat plate therebetween. Together with the second of the third flat plate
The restriction flow path is provided in a groove shape on the surface opposite to the flat plate, and the communication flow path connecting the restriction flow path and the common ink chamber is provided in the third flat plate in a penetrating manner. It is a thing.

According to a fifth aspect of the present invention, a plurality of nozzles for ejecting ink onto the printing surface, pressure chambers provided corresponding to the respective nozzles and connected to the nozzles, and one end of the pressure chamber are provided. A restriction channel connecting one end,
An ink jet head having a flat plate laminated structure having a common ink chamber for distributing and supplying ink to the pressure chamber, which is connected to the other end of the restriction flow path, and the flat plate constituting the head unit is .First forming the pressure chamber
A flat plate, and a second flat plate that forms the common ink chamber,
At least a third flat plate that is located between the first flat plate and the second flat plate that forms the restricted flow path, and the restricted flow path is long in the plane direction of the third flat plate. Is formed while penetrating in the plate thickness direction,
The cross section of the restricted flow path, which is orthogonal to the length direction, has the smallest cross-sectional area in the ink flow path from the common ink chamber to the pressure chamber. As a result, the depth of the restricted flow path can be secured with low cost and high accuracy without using half etching, and a predetermined flow path resistance can be obtained at low cost. Further, it is possible to arrange the restriction flow path in any direction on a plane parallel to the pressure chamber including a position overlapping the pressure chamber in the stacking direction, and it is possible to make the inkjet head compact and highly integrated. Further, by forming the pressure chamber and the restriction flow path on separate flat plates, it is possible to reduce the cost by eliminating the problem that both must be processed simultaneously with high precision as in the conventional case. These can be easily realized by the following configurations.

According to a sixth aspect of the present invention, the limiting flow passage is located at a position closer to both ends connecting to the common ink chamber and the pressure chamber.
The middle section has a smaller cross-sectional area.

In the seventh aspect, the third flat plate is the thinnest of the laminated flat plates constituting the ink jet head.

According to another aspect of the present invention, the limiting flow path is located between the common ink chamber and the pressure chamber in the stacking direction of the flat plates, and is located between the third flat plate and the first flat plate. 4 flat plates are interposed, a communication flow path that connects the restriction flow path and the pressure chamber is provided in the fourth flat plate, and a fifth flat plate is interposed between the third flat plate and the second flat plate. The fifth flat plate is provided with a communication flow path that connects the restriction flow path and the common ink chamber.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a perspective view of a color ink jet printer including an ink jet head according to an embodiment of the present invention.

In FIG. 1, the printer head 63 of the color ink jet printer 100 is provided for each color in order to eject ink of four colors (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. In addition, each ink supply passage 4
A joint member 47 made of rubber or the like, which can be brought into close contact with an ink supply port (described later) of the inkjet head 6, 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 adhered and laminated to the cavity plate 10 via 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, the nozzle plate 11 is provided with a large number of nozzles 35 for ejecting ink having a minute diameter (about 25 μm in this embodiment) by a press. The nozzles 35 are arranged in two staggered rows at a minute interval along the longitudinal direction of the nozzle plate 11.

As shown in FIG. 5, the base plate 15 (first flat plate P ₁ ) has a plurality of pressure chambers 36.
The base plate 15 is formed in two rows in a staggered arrangement along the longitudinal direction. The concrete 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 so that the longitudinal direction thereof is orthogonal to the longitudinal direction of the base plate 15.

Then, as shown in FIG. 6, one end portion 36a of each pressure chamber 36 has three spacer plates 14X.14.
Y ・ 14Z, two manifold plates 13X ・ 13
The nozzles 35 in the nozzle plate 11 are communicated with each other through Y and the through holes 37 of minute diameter which are also formed in the damper plate 12 in a staggered arrangement.

Each pressure chamber 36 is provided in the upper spacer plate 14X (fourth flat plate P ₄ ) adjacent to the base plate 15.
An ink supply hole (communication flow path) 38 is formed at a position corresponding to, and the ink supply hole 38 is connected to the other end 36b of each pressure chamber 36. Immediately intermediate spacer plate 14Y positioned on the lower side (third flat plate P ₃₎ in the diaphragm portion (restricted flow passage) 43, the elongated along the surface direction of the intermediate spacer plate 14Y (specifically, the pressure chamber 36 is elongated in parallel with the longitudinal direction of 36) and is formed so as to penetrate in the plate thickness direction.
The ink supply hole 38 communicates with one end of the throttle portion 43. The other end of the narrowed portion 43 has the lower spacer plate 1
4Z (fifth flat plate P ₅ ) is communicated with a common ink chamber 7, which will be described later, through an introduction hole (communication flow path) 44 provided so as to penetrate.

From the common ink chamber 7 to the throttle 43 and the pressure chamber 3
FIG. 7 is a perspective view showing the outline of the ink flow path from 6 to the nozzle 35, and in this drawing, the throttle portion 43.
Is highlighted with a solid line. As shown in this FIG.
The narrowed portion 43 has a shape that is narrowed down in the central portion in the longitudinal direction. That is, the flow path cross-sectional area (throttle portion 43) at the intermediate portion in the longitudinal direction is larger than the end portion connected to the pressure chamber 36 via the ink supply hole 38 and the end portion connected to the common ink chamber 7 via the introduction hole 44. Area of the cross section orthogonal to the length direction of
It is configured such that S is small. The flow passage cross-sectional area S of the middle portion of the narrowed portion 43 is set to the minimum in the ink flow passage from the common ink chamber 7 to the pressure chamber 36. Due to this diaphragm action, the actuator 2 described later
When 0 is driven, the pressure generated in the ink in the pressure chamber 36 is restricted from moving toward the common ink chamber 7 side, and the nozzle 35
It is possible to efficiently direct the ink to the side and eject the ink efficiently. In addition, since both ends of the narrowed portion 43 are configured to have a larger flow passage cross-sectional area than the middle portion, even if a slight misalignment occurs when the three spacer plates 14X, 14Y, and 14Z are bonded, The communication between the hole 44 and the narrowed portion 43 and between the narrowed portion 43 and the ink supply hole 38 is surely ensured (the margin for sticking misalignment is increased).

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 13
It is recessed so as to open only toward X. In addition,
In this embodiment, the ink chamber half portions 13a and 13b are both formed by etching, and the lower half portion 13b is formed by half etching. 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. Therefore, in this embodiment, the two manifold plates 13X.1 are
3Y corresponds to the second flat plate P ₂ of the present invention.

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 port 39 corresponding to each of 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 ports 39, 39 are formed at a position close to the end of the row formed by the plurality of pressure chambers 36, 36. 39 and 39 are arranged close to each other.

With the structure of the cavity plate 10 as described above, the common ink chamber 7 is connected to the ink supply ports 39, 39 described above.
The ink that has flowed into the inside 7 is drawn from the introduction hole 44 to the throttle portion 43.
→ It is supplied from the other end 36b side of each pressure chamber 36 via the ink supply hole 38. And each pressure chamber 3
6, the ink to which the ejection energy is given by the actuator 20 described later passes from the one end portion 36a to the through holes 37, 37 ...
5 is injected.

FIG. 8 is an exploded enlarged perspective view of the actuator 20. The actuator 20 is shown in FIG.
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 the 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 can be laminated not only one by one as shown in the drawing but also by alternately laminating a plurality of sheets. Each drive electrode 24 and common electrode 2
The respective regions of the piezoelectric sheets 21 and 22 sandwiched between the pressure chambers 5 and 5 become 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 recessed groove 30 is formed at one end 24a of each drive electrode 24, and a second recessed 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 in 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 present embodiment, the limiting flow path is the flat plate (the first flat plate P _{1 which is the} base plate 15) forming the pressure chamber 36 and the different flat plate (the third flat plate P _{3 which is the} intermediate spacer plate 14Y). The narrowed portion 43 is formed. The narrowed portion 43 is formed long along the surface direction of the intermediate spacer plate 14Y, and extends from one end connecting to the pressure chamber 36 via the ink supply hole 38 to a plane formed by the plurality of pressure chambers 36. It is formed by extending in a parallel direction. Therefore, when arranging the flow paths corresponding to the nozzles 35 inside the inkjet head, it is possible to avoid interference between the pressure chamber 36 and the throttle portion 43. As a result, the inkjet head 6 can be made compact, and it is possible to easily meet the demand for higher integration based on the need for higher resolution. Further, since the throttle portion 43 extends in the direction parallel to the plane formed by the plurality of pressure chambers 36, the increase of the flow path space in the flat plate stacking direction can be made small.

In particular, in the present embodiment, the path from the throttle portion 43 to the pressure chamber 36 via the ink supply hole 38 has a U-shape in side view, and the ink flowing into the throttle portion 43 is shown in FIG. As shown in FIG. 5, when the ink reaches the pressure chamber 36 from the ink supply hole 38, the direction is reversed and the ink flows in a folded shape. In this way, since the pressure chamber 36 and the narrowed portion 43 are arranged so as to overlap in the flat plate stacking direction, the narrowed portion 43, the pressure chamber 36, and the ink supply hole 38 are introduced from the introduction hole 44.
The ink flow path reaching the nozzle 35 via the can be reasonably accommodated within a small width (width W shown in FIGS. 6 and 7).

In the present embodiment, as shown in FIG. 6, the throttle portion 43 is formed so as to penetrate the intermediate spacer plate 14Y, which is the third flat plate P ₃ , so that the flow path resistance of the throttle portion 43 is reduced. The variation is suppressed to reduce the variation in the ink ejection amount from the nozzle 35. That is,
Since the flow path resistance of the narrowed portion (restricted flow path) 43 has a great influence on the flow of ink from the pressure chamber 36 toward the common ink chamber 7 side during ejection as described above, the flow path resistance of this restricted flow path is Accurate determination is extremely important for suppressing variations in the amount of ink ejected from the nozzles 35. However, as shown in the conventional configuration of FIG. 11, since the limiting flow path 36d is formed in a groove shape from one side of the flat plate 15 by half etching, the etching rate varies depending on factors such as the temperature of the etching solution and the degree of deterioration. It fluctuates easily, which leads to variations in groove depth. Here, the flow path resistance of the restricted flow path 36d is the flow path cross-sectional area (= groove depth ×
Since it is inversely proportional to the width of the groove, the variation in the depth of the groove is directly connected to the variation in the flow path resistance, resulting in the deterioration of the printing quality due to the excessive or insufficient ink ejection amount. On the other hand, in the present embodiment, as shown in FIGS. 5 and 6, the narrowed portion 43, which is the restricted flow path, is formed in the intermediate spacer plate 14Y so as to penetrate in the plate thickness direction. The accuracy depends only on the accuracy of the thickness of the intermediate spacer plate 14Y. This means that the depth of the narrowed portion 43, and consequently the flow passage cross-sectional area (area S shown in FIG. 7) can be accurately determined, and as a result, the variation in flow passage resistance can be reduced and the quality of ink jet printing can be improved. Be improved.

The thickness of the intermediate spacer plate 14Y, which is the third flat plate P ₃ , is smaller than that of the other flat plates. Specifically, of the eight flat plates 11 to 15 that form the cavity plate 10, the intermediate spacer plate 14
The thickness of Y is minimized. Here, as described above, since the narrowed portion 43 is formed in a penetrating manner, the depth of the narrowed portion 43 matches the thickness of the intermediate spacer plate 14Y. Therefore, the depth of the narrowed portion 43 is also reduced. Here, if the depth of the narrowed portion 43 is large, the flow passage cross-sectional area S required to impart an appropriate resistance to the ink flow is obtained.
In order to obtain (= width × depth), the width of the flow path must be extremely narrowed, which makes processing extremely difficult. However, in the present embodiment, since the thickness of the intermediate spacer plate 14Y is small, the depth of the throttle portion 43 can be reduced, and it is not necessary to narrow the flow passage width of the throttle portion 43, so that the throttle portion 43 can be easily processed. Further, with the above configuration, not only etching of the narrowed portion 43 but also punching by a press becomes possible. In this case, press working is further facilitated by appropriately rounding the portion where the narrowed portion in the middle of the narrowed portion 43 and the enlarged portions at both ends are connected. In the etching process, the width of the narrowed portion 43 is ± 15 μm
Can be manufactured with an accuracy of 20 μm, but ± 5 μ in press processing
Can be manufactured with an accuracy of m.

However, the narrowed portion 43 is not formed in a penetrating manner,
Even with a structure formed by so-called half etching, the effect of the present invention that the ink flow path is contained in a compact space can be achieved. Below, two modified examples in which the narrowed portion 43 is formed by half etching are shown in FIGS.
Will be described with reference to.

In the configuration shown in FIG. 9 (Modification 1),
Manifold plate 13X forming the common ink chamber 7
· 13Y (second plate P ₂₎ and the intermediate spacer plate 14
Y (third flat plate P ₃ ) are laminated adjacent to each other without a flat plate therebetween (that is, the lower spacer plate 14Z is omitted). Then, the intermediate spacer plate 14Y, which is the third flat plate P ₃ , is half-etched on the surface facing the pressure chamber 36 to form the elongated narrowed portion 43 in a groove shape. One end of the throttle portion 43 is connected to the other end portion 36b of the pressure chamber 36 via an ink supply hole 38 formed in the upper spacer plate 14X so as to penetrate therethrough. The other end of the narrowed portion 43 is connected to the common ink chamber 7 via an introduction hole 44 formed in the intermediate spacer plate 14Y so as to penetrate therethrough. In the configuration of the first modification, the ink flow path can be accommodated within the compact width W as described above, and the lower spacer plate 14Z can be omitted, so that the number of parts can be reduced.

In the configuration shown in FIG. 10 (Modification 2), the base plate 15 (first flat plate P ₁ ) forming the pressure chamber 36 and the intermediate spacer plate 14Y (third flat plate P ₃ ) are placed between the base plate 15 and the intermediate spacer plate 14Y. It is laminated without a flat plate (that is,
The upper spacer plate 14X is omitted). Then, with respect to the third flat plate P ₃ serving intermediate spacer plate 14Y, it is subjected to half-etching on the surface facing the common ink chamber 7 side, and an elongated aperture 43 and recessed in a groove shape. One end of the narrowed portion 43 is provided with a pressure chamber 36 through an ink supply hole 38 formed in the intermediate spacer plate 14Y in a penetrating manner.
Is connected to the other end 36b. The other end of the narrowed portion 43 is connected to the common ink chamber 7 via an introduction hole 44 formed in the lower spacer plate 14Z so as to penetrate therethrough. Like the above-described Modification 1, the structure of Modification 2 can accommodate the ink flow path within the compact width W and can omit the upper spacer plate 14X, so that the number of components can be reduced.

[0050]

Since the present invention is constructed as described above,
The following effects are achieved.

That is, as described in claim 1, a plurality of nozzles for ejecting ink to the printing surface, pressure chambers provided corresponding to each of the nozzles and connected to the nozzles, and the pressure chambers of the pressure chambers. An ink jet head having a flat plate laminated structure, which has a limiting flow channel connecting one end to one end and a common ink chamber connected to the other end of the limiting flow channel for distributing and supplying ink to the pressure chambers. The flat plate that constitutes the head unit includes: a first flat plate that forms the pressure chamber; a second flat plate that forms the common ink chamber; and a first flat plate that forms the restricted flow path. And a third flat plate located between the second flat plate and the third flat plate, and the restriction flow path is formed in the third flat plate so as to be long along the surface direction of the third flat plate, and from the one end connected to the pressure chamber. Equipped with multiple pressure chambers Since extending in the direction parallel to the plane of,
The ink channels can be reasonably arranged in a compact space. That is, the restriction channel is on the third flat plate, and the pressure chamber is on the first.
Since the restriction channel and the pressure chamber are formed on separate plates such as a flat plate, it is possible to avoid interference between the pressure chamber and the restriction channel when arranging the ink channel. Also,
Since the restriction flow path is formed in the direction parallel to the plane formed by the plurality of pressure chambers, the increase in the space for disposing the flow path in the flat plate stacking direction is slight. As a result, it is easy to improve the degree of integration of the ink flow path, making the inkjet head compact and
It is possible to easily deal with the high-density arrangement of the nozzles, which is required due to the demand for higher image resolution. Further, by forming the pressure chamber and the restriction flow path on separate flat plates, it is possible to solve the conventional problem that both must be processed at the same time with high precision, and the manufacturing cost can be reduced.

According to a second aspect of the present invention, the limiting flow path is the third
A connecting flow that is formed through the flat plate and has a fourth flat plate interposed between the third flat plate and the first flat plate to connect the limiting flow path and the pressure chamber to the fourth flat plate. Since the passage is provided, since the limiting flow passage is formed in the flat plate in a penetrating manner, the accuracy of the cross-sectional area of the limiting flow passage can be easily improved as compared with the case where the limiting flow passage is recessed. That is, in the case of forming a groove shape, the variation in the plate thickness direction of the processed shape of the groove leads to the variation of the cross-sectional area of the restricted flow path, resulting in an excess or an excessive amount of ink jet from the nozzle, This will cause deterioration of print quality. In this respect, in the present invention, since the restricted flow passage is formed in the flat plate in a penetrating manner, the dimensional accuracy in the plate thickness direction depends only on the accuracy of the thickness of the flat plate. Therefore, the restricted flow path can be processed so that its cross-sectional area (flow path resistance) can be accurately set to a desired value, and as a result, variations in the ink ejection amount can be suppressed and printing quality can be improved.
Moreover, since the connecting flow path connecting the pressure chamber and the restriction flow path is formed on the fourth flat plate between the third flat plate and the first flat plate, the partition wall separating the pressure chamber and the restriction flow path is formed. The rational structure is such that the connecting flow path is formed in a penetrating manner on the fourth flat plate that plays a role of. As a result, the structure of the flow path from the common ink chamber to the pressure chamber can be simplified.

According to a third aspect of the present invention, the first flat plate and the third flat plate are laminated without a flat plate interposed therebetween, and the limiting flow path is grooved on the surface of the third flat plate opposite to the first flat plate. Since the connecting flow path that connects the limiting flow path and the pressure chamber is provided in a penetrating manner in the third flat plate, the flat plate between the third flat plate and the first flat plate Can be omitted, the number of parts can be reduced, and the manufacturing cost
It can contribute to the reduction of manufacturing man-hours.

According to a fourth aspect of the present invention, the restricted flow path is between the common ink chamber and the pressure chamber in the stacking direction of the flat plates, and the second flat plate and the third flat plate are stacked without a flat plate therebetween. And the second of the third flat plate
The restriction flow path is provided in a groove shape on the surface opposite to the flat plate, and the communication flow path connecting the restriction flow path and the common ink chamber is provided in the third flat plate in a penetrating manner. So
Since the restricting flow path is between the common ink chamber and the pressure chamber, it is possible to rationally arrange the common ink chamber → the restricting flow path → the pressure chamber and the flowing ink flow path. Furthermore, since the flat plate between the third flat plate and the second flat plate can be omitted, the number of parts can be reduced, which can contribute to the reduction of manufacturing cost and man-hours.

According to a fifth aspect of the present invention, a plurality of nozzles for ejecting ink onto the printing surface, pressure chambers provided corresponding to the respective nozzles and connected to the nozzles, and one end of the pressure chambers are provided. A restriction flow path connecting one end thereof,
An ink jet head having a flat plate laminated structure having a common ink chamber for distributing and supplying ink to the pressure chamber, which is connected to the other end of the restriction flow path, and the flat plate constituting the head unit is .First forming the pressure chamber
A flat plate, and a second flat plate that forms the common ink chamber,
At least a third flat plate that is located between the first flat plate and the second flat plate that forms the restricted flow path, and the restricted flow path is long in the plane direction of the third flat plate. Is formed while penetrating in the plate thickness direction,
Since the cross section of the limiting flow path which is orthogonal to the length direction has the smallest cross-sectional area in the ink flow path from the common ink chamber to the pressure chamber, the ink flow path can be rationalized in a compact space. Can be placed in That is, the limiting channel and the pressure chamber are formed on separate flat plates such that the limiting channel is on the third flat plate, the pressure chamber is on the first flat plate, and so on. It is possible to avoid interference with the restricted flow path. Further, since the restricted flow path is formed long on the third flat plate along its surface direction, the increase of the space for disposing the flow path in the flat plate stacking direction is slight. As a result, it is easy to improve the degree of integration of the ink flow path, and it is possible to easily deal with the downsizing of the inkjet head and the high-density arrangement of nozzles in response to the demand for higher image resolution.
Further, by forming the pressure chamber and the restriction flow path on separate flat plates, it is possible to solve the conventional problem that both must be processed at the same time with high accuracy, and the manufacturing cost can be reduced. Further, since the limiting flow passage is formed so as to penetrate the third flat plate, the accuracy of the cross-sectional area of the limiting flow passage can be improved as compared with the case where the limiting flow passage is recessed like the effect of the second aspect. It can be easily improved. Since the cross-sectional area of this cross-section is the minimum cross-sectional area in the ink flow path from the common ink chamber to the pressure chamber, the flow path resistance of this restriction flow path causes the pressure chamber to the common ink chamber during ejection. Since the ink flow toward the nozzle can be appropriately controlled, variations in the amount of ink ejected from the nozzles are reduced, and deterioration of print quality is avoided.

According to a sixth aspect of the present invention, the limiting flow passage is located closer to both ends than the common ink chamber and the pressure chamber.
Since the cross-sectional area is smaller in the middle, the flow path resistance is accurately determined in the middle part of the restricted flow path, and at the same time, the cross-sectional area is increased at both ends, so connection to the common ink chamber or pressure chamber is reliable. Done That is, the third flat plate and the second
Even if there is a slight displacement between the flat plate and the third flat plate and the first flat plate, even if there is a slight displacement between the third flat plate and the first flat plate, between the common ink chamber and the restricted flow path, and between the restricted flow path and the pressure. The connection between the rooms is maintained securely.

Since the third flat plate is the thinnest of the laminated flat plates constituting the ink-jet head, the depth of the narrowed portion (which is equal to the thickness of the third flat plate) can be made small. Even if the width of the portion is increased to some extent, it is possible to generate the flow path resistance necessary for reducing the ink flow rate. Therefore, it is easy to form the narrowed portion.

According to an eighth aspect of the present invention, the limiting flow path is located between the common ink chamber and the pressure chamber in the stacking direction of the flat plates, and between the third flat plate and the first flat plate. A fourth flat plate is interposed, a communication flow path connecting the restriction flow path and the pressure chamber is provided in the fourth flat plate, and a fifth flat plate is interposed between the third flat plate and the second flat plate. The fifth flat plate is provided with the connecting flow passage that connects the limiting flow passage and the common ink chamber, so that the limiting flow passage is located between the common ink chamber and the pressure chamber. It is possible to rationally arrange the common ink chamber, the restricted flow channel, the pressure chamber, and the flowing ink flow channel. Further, a communication flow path connecting the pressure chamber and the restriction flow path, a communication flow path connecting the restriction flow path and the common ink chamber to the fourth flat plate between the third flat plate and the first flat plate, Since it is formed on the fifth flat plate between the flat plate and the second flat plate, respectively, it functions as a partition wall that separates the pressure chamber, the restriction channel, and the common ink chamber from each other. 5 It is a rational structure in which the connecting flow path is formed in a flat plate in a penetrating manner. As a result, the structure of the flow path from the common ink chamber to the pressure chamber can be simplified.

[Brief description of drawings]

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

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 a perspective view showing an ink flow path from a common ink chamber to a nozzle via a throttle / pressure chamber.

FIG. 8 is an exploded perspective view showing a laminated structure of an actuator.

FIG. 9 is a cross-sectional view showing a modified example 1 of the configuration of the throttle unit.

FIG. 10 is a cross-sectional view showing a modified example 2 of the configuration of the diaphragm unit.

FIG. 11 is a cross-sectional view showing the structure of a restricted flow path of a conventional inkjet head.

[Explanation of symbols]

6 inkjet head 7 common ink chambers 11 to 15 flat plate P ₁ first flat plate (base plate 15) P ₂ second flat plate (upper spacer plate 14X) P ₃ third flat plate (intermediate spacer plate 14Y) P ₄ fourth flat plate (lower side Spacer plate 14Z) P _5th flat plate (manifold plate 13X ・ 13
Y) 35 nozzle 36 pressure chamber 38 ink supply hole (communication flow path) 43 throttle portion (restriction flow path) 44 introduction hole (communication flow path)

Claims (8)

[Claims] 1. A plurality of nozzles for ejecting ink to a printing surface, pressure chambers provided corresponding to the respective nozzles and connected to the nozzles, and one end of the pressure chamber is connected to one end of the pressure chamber. What is claimed is: 1. An inkjet head having a flat plate laminated structure, comprising: a restriction channel; and a common ink chamber connected to the other end of the restriction channel for distributing and supplying ink to the pressure chamber. The constituting flat plates are: a first flat plate that forms the pressure chamber; a second flat plate that forms the common ink chamber; a space between the first flat plate and a second flat plate that forms the restriction flow path. At least a third flat plate located at, and the restriction channel is formed in the third flat plate to be long along the surface direction thereof, and a plane formed by a plurality of pressure chambers from one end connected to the pressure chambers. One parallel to And wherein the extending the ink jet head. 2. The ink jet head according to claim 1, wherein the restriction channel is formed in a penetrating shape on a third flat plate, and a fourth gap is formed between the third flat plate and the first flat plate.
A flat plate interposed, and a connecting flow path connecting the limiting flow path and the pressure chamber to the fourth flat plate,
Inkjet head. 3. The inkjet head according to claim 1, wherein the first flat plate and the third flat plate are laminated without a flat plate interposed therebetween, and a surface of the third flat plate opposite to the first flat plate. The limiting flow path is provided in a groove shape, and the third flat plate is provided with a connecting flow path that connects the limiting flow path and the pressure chamber in a penetrating manner.
Inkjet head. 4. The ink jet head according to claim 1, wherein the restricted flow path is between the common ink chamber and the pressure chamber in a stacking direction of the flat plates, and the second flat plate and the third flat plate. And the limiting flow path is provided in a groove shape on the surface of the third flat plate opposite to the second flat plate, and the third flat plate has the limiting flow path and the limiting flow path. An ink jet head, characterized in that a communication channel connecting to a common ink chamber is provided in a penetrating manner. 5. A plurality of nozzles for ejecting ink to a printing surface, pressure chambers provided corresponding to the respective nozzles and connected to the nozzles, and one end of the pressure chamber is connected to one end of the pressure chamber. What is claimed is: 1. An inkjet head having a flat plate laminated structure, comprising: a limiting flow channel; and a common ink chamber connected to the other end of the limiting flow channel for distributing and supplying ink to the pressure chamber. The constituting flat plates are: a first flat plate that forms the pressure chamber; a second flat plate that forms the common ink chamber; a space between the first flat plate and a second flat plate that forms the restriction flow path. At least a third flat plate located at, and the limiting flow channel is formed in the third flat plate so as to be long along the surface direction thereof and penetrate through in the plate thickness direction. The path is along its length An ink jet head, wherein a cross section orthogonal to each other has a minimum cross sectional area in an ink flow path from the common ink chamber to the pressure chamber. 6. The ink jet head according to claim 5, wherein the limiting channel has a smaller cross-sectional area in the middle thereof than at both ends connecting to the common ink chamber and the pressure chamber. Characteristic inkjet head. 7. The ink jet head according to claim 5 or 6, wherein the third flat plate is the thinnest of the laminated flat plates constituting the ink jet head. 8. The inkjet head according to any one of claims 5 to 7, wherein the restriction channel is provided between the common ink chamber and the pressure chamber in a stacking direction of the flat plates. While being positioned, a fourth flat plate is interposed between the third flat plate and the first flat plate, and a communication flow path that connects the restriction flow path and the pressure chamber is provided on the fourth flat plate, and A fifth flat plate is interposed between the third flat plate and the second flat plate, and the fifth flat plate is provided with a communication flow channel that connects the restriction flow channel and the common ink chamber. Inkjet head.