JPH06191024A - Ink jet print head and ink jet printer - Google Patents

Abstract

PURPOSE:To reduce the resistance of an ink flow path from a pressure chamber to the ink jet port of a nozzle, to improve the ink jetting speed from the ink jet port and the response and to realize accurate, high-speed printing. CONSTITUTION:A plurality of pressure chambers 2a-2n are juxtaposed so that the width is expanded toward the outer surface in the radial pattern from the central edge part in two lines, which are arranged in the straight-line pattern. A common ink path surrounds the pressure chambers 2a-2n and communicates with the pressure chambers 2a-2n. An ink introducing port supplies the ink into the common ink path. These pats are formed in a substrate 1. A nozzle 5 is formed so as to penetrate the substrate 1 at the central edge part. Piezoelectric elements are attached to a moving plate, which is attached to the pressure-chamber forming surface of the substrate 1, and to the outer surface of a vibrating plate facing the pressure chamber, respectively, in a piezoelectric type head unit, which is assembled to a base stage. In this ink jet print head, the depth of the flow path 6 of the high-density, narrow-width pressure chamber in the vicinity of the central edge part is increased. The nozzle 5 is formed so as to penetrate the substrate 1 from the bottom surface of the deep flow path 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet print head used for, for example, a printer, a fax machine, a plotter, a bar code printer, a digital copy machine, and an ink jet printer. The present invention relates to an ink jet print head and an ink jet printer that are attached to a recording medium such as paper to obtain a recording.

[0002]

2. Description of the Related Art Conventional inkjet printers are roughly classified into a continuous type and an on-demand type.
The ink is water-based or oil-based.

In the continuous type, ink is continuously ejected from a nozzle, and ink unnecessary for recording is recovered and reused. The head has high responsiveness, but an ink recovery mechanism is required and the apparatus is complicated. It is expensive.

On the other hand, the on-demand type ejects ink only when necessary, and the response of the head is low, but the device is simple and inexpensive.

The on-demand type includes an electrostatic attraction type that draws ink from a nozzle by electrostatic force, and a pressure pulse type called an impulse jet that pressurizes ink in a pressure chamber and pushes ink from the nozzle.

The pressure pulse type includes a piezoelectric type and a bubble type. The piezoelectric type pressurizes ink by a piezoelectric (electrostrictive) element. The one-chamber type in which ink is supplied through a pressure chamber and the pressure type There is a two-chamber type having two chambers, a chamber and an ink supply chamber.

The one-chamber type includes a Kaiser type having a flat pressure chamber and a soltan type having a cylindrical pressure chamber. In addition, the two-chamber type includes a stem type that directly supplies ink to the vicinity of the nozzle.

FIG. 12 shows the basic principle of the above Kaiser type piezoelectric head unit. The ink supply passage 102, the pressure chamber 103 and the nozzle 104 are formed on the surface of the substrate 101.
Are continuously formed. Then, the diaphragm 105 is arranged on the surface of the substrate 101, and the outer surface of the diaphragm 105 is
A piezoelectric element 106 is provided so as to face the pressure chamber 103, and a signal generation source 107 is connected so as to apply a voltage between the front and back surfaces of the piezoelectric element 106. An ink container 109 is connected to the ink supply path 102 via a pipe 108.

In the above structure, when a voltage is applied from the signal source 107 to the piezoelectric element 106, the piezoelectric element 106
Causes the vibrating plate 105 to bend, and the ink 1 in the pressure chamber 103
10 is ejected from the nozzle 104 as an ink droplet 110a onto the recording paper 111 for recording.

Then, when the voltage application to the piezoelectric element 106 is released after the ink is ejected, the vibrating plate 105 returns to its original state, and the ejected ink passes through the ink supply path 102 and the pipe 108 by the nozzle capillary force. The pressure chamber 103 is replenished from the ink container 109.

FIG. 13 is a plan view of a substrate of a conventional piezoelectric head unit from which a vibration plate is removed, and FIG. 14 is a transverse cross-sectional view with the vibration plate attached.

In FIGS. 13 and 14, a substrate 121 made of photosensitive glass is provided with a large number of pressure chambers 122a to 122a arranged radially from the center end of two linear rows.
22n, a common ink passage 123 that surrounds the pressure chambers 122a to 122n and communicates with the pressure chambers, and the common ink passage 12
An ink inlet port 124 for supplying the ink to 3 is formed by etching. And each pressure chamber 122a
Nozzles 125 are formed at the central ends of the straight lines up to 122n in the plate thickness direction. In this way, each pressure chamber 1
By forming 22a to 122n radially,
The number of nozzles per single area can be increased.

The vibrating plate 126 is made of, for example, glass, and is attached to the pressure chambers 122a to 122n of the substrate 121, the common ink 123, and the surface on which the ink introducing port 124 is formed by screws, adhesion or the like.

The piezoelectric elements 127a to 127n are the pressure chamber 12
It is attached to the position of the diaphragm 126 corresponding to each of 2a to 122n. And each piezoelectric element 127a-
A flexible cable 128 for applying a signal voltage from a signal generation source (not shown) is connected to 127n.

FIG. 15 is a diagram showing a process of processing the above-mentioned photosensitive glass substrate 1. First, a pattern mask 132 for forming a pressure chamber is attached to the surface of the photosensitive glass substrate 121, and exposure is performed from this pattern mask 132 side. (Step 15-
1). After the exposure, the pattern mask 132 is removed and an etching process is performed to form the pressure chamber 122a (to 122n) (step 15-2). After that, the nozzle 1 is formed by laser processing or the like.
25 is formed (step 15-3).

Then, the vibrating plate 126 is joined to the pressure chamber forming surface of the photosensitive substrate 121 (cutting step 15-4), and the piezoelectric elements 127a to 127n are opposed to the pressure chambers 122a to 122n on the outer surface of the vibrating plate 126. Install (Step 15-
5).

FIG. 16 is a cross-sectional view showing an ink jet print head to which the above-mentioned piezoelectric head unit is applied. In a base 129 made of metal and resin having high rigidity, parts corresponding to the piezoelectric elements 127a to 127n are provided. The concave portion 130 is formed, and the peripheral portion and the central portion of the diaphragm 126 are bonded and fixed to the base 129 by the adhesive 131 in the other portions.

Next, the operation will be described. Due to the strain of the piezoelectric element to which the signal voltage is applied, the vibrating plate 126 in the portion corresponding to the piezoelectric element is deformed, and the volume of the pressure chamber is changed by this deformation to eject ink from the nozzle 125. In this case, the diaphragm 1 corresponding to the nozzle 125
26 is a protrusion 129a of the base 129 as a supporting portion.
Since it is supported by, the vibrating plate portion of the piezoelectric element adjacent to the deformed piezoelectric element is not unnecessarily bent.

When the vibrating plate 126 returns to the original state after the ink is ejected, the ejected ink is replenished to the pressure chamber through the ink introduction port 124 and the common ink passage 123.

[0020]

Since the conventional ink jet print head is constructed as described above,
Since the plurality of nozzles are formed with high density and the flow path from each pressure chamber to the ink ejection port of the nozzle is extremely narrow and long, the ink flow path resistance is large. For this reason, ink droplet ejection becomes unstable, and the printing quality is degraded.

Therefore, it is conceivable to make the substrate 121 thinner, but if the substrate 121 is made thinner, it is more susceptible to vibration of the piezoelectric element. It is also conceivable to increase the drive voltage applied to the piezoelectric elements 127a to 127n, but in this case, it takes time to damp the vibration of the piezoelectric element, and in either case, the response is poor and accurate high-speed printing is difficult. There was a problem that was.

The present invention has been made to solve the above problems, and reduces the flow path resistance of ink to make the substrate thin and increase the drive voltage applied to the piezoelectric element. It is an object of the present invention to obtain an inkjet print head and an inkjet printer that can realize high-speed printing with high accuracy without any problem.

[0023]

SUMMARY OF THE INVENTION An ink jet print head according to the present invention includes a plurality of pressure chambers, which are arranged in a straight line so as to radially widen from the center end portion toward the outer periphery. A common ink passage that surrounds each pressure chamber and communicates with the pressure chamber, a substrate having an ink inlet for supplying ink to the common ink passage, and two central rows of the pressure chambers communicate with each other. A piezoelectric head unit having a plurality of nozzles formed as described above, a diaphragm attached to the pressure chamber forming surface of the substrate, and a piezoelectric element attached to the outer surface of the diaphragm facing the pressure chamber, respectively. In the ink jet print head assembled in step 1, the flow path depth of the high-density narrow pressure chamber flow path near the central end portion is increased as in claim 1, and the substrate is penetrated from the bottom surface of the deep flow path. To form the nozzle Alternatively, as in claim 2, the nozzle forming plate is attached to the back surface of the substrate so that the high-density narrow-width pressure chamber flow passage near the central end portion is penetrated to the back of the substrate and the nozzle is aligned with the through-flow passage. It is a thing.

An ink jet printer according to a third or a fourth aspect of the present invention has an ink jet print head according to the first or second aspect incorporated in a carriage, and is configured to reciprocate in the row direction of recording paper. Is.

[0025]

In the ink jet print head according to the present invention, the flow path depth of the high density narrow pressure chamber flow path near the central end portion is increased, and the nozzle penetrates the substrate from the bottom surface of the deep flow path. Or a high-density narrow pressure chamber channel near the central end is penetrated to the back of the substrate, and a nozzle forming plate is attached to the back surface of the substrate so that the nozzle matches the through channel. The flow resistance of the ink from the pressure chamber to the ink ejection port of the nozzle can be reduced, the ink ejection speed and responsiveness from the ink ejection port can be improved, and accurate high-speed printing can be realized.

[0026]

【Example】

Example 1. Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view of a substrate of a piezoelectric head unit from which a diaphragm is removed, and FIG. 2 is a diagram showing a state where the diaphragm is attached.
It is a cross-sectional view taken along the line AA of FIG.

In FIGS. 1 and 2, a substrate 1 made of a photosensitive glass is provided with a large number of pressure chambers 2a to 2n which are arranged side by side so as to radially expand from a straight central end portion toward the outer periphery. A common ink passage 3 that surrounds the pressure chambers 2a to 2n and communicates with the pressure chamber, and an ink inlet 4 that supplies ink to the common ink passage 3 are formed by etching. Then, the depth of the high-density narrow pressure chamber channel 6 near the central end of each pressure chamber 2a to 2n is increased so that the nozzle 5 penetrates the substrate 1 from the bottom of the deep channel 6 and Has been formed.

FIG. 3 is a diagram showing the processing steps of the substrate 1. First, a pattern mask 7 for nozzle formation is attached to the back surface of the photosensitive glass substrate 1, and exposure is performed from this pattern mask 7 side (step 3-1). After the exposure, the pattern mask 7 is removed and etching is performed to form the nozzle 5 (step 3-2), and the wax 8 is filled so that the etching liquid does not enter the nozzle 5 (step 3-3).

Then, a pattern mask 9 for forming a deep hole is attached to the surface of the photosensitive glass substrate 1, exposure is performed from the side of the pattern mask 9 (step 3-4), and thereafter,
The pattern mask 9 is removed and an etching process is performed to form a concave portion which becomes the deep hole 6 on the surface of the photosensitive glass substrate 1 corresponding to the nozzle 5 (step 3-5).

After the formation of the recess, the pattern mask 10 for forming the pressure chamber is attached to the photosensitive glass substrate 1, and the pattern mask 10 is exposed to light (step 3-6).
After the exposure, when the pattern mask 10 is removed and etched, the surface of the photosensitive glass substrate 1 is further etched,
The bottom surface of the deep hole 6 formed in the above step 3-5 is the above step 3
It connects with the nozzle 5 formed in -2 (process 3-7).

Thereafter, the wax 8 filled in the nozzle is removed (step 3-8), the vibration plate 18 is joined to the pressure chamber forming surface of the substrate 1 (step 3-9), and the outer surface of the vibration plate 18 is pressed. The piezoelectric elements 19a to 19n are attached so as to face the chamber (step 3-10).

The ink flow path resistance R (N · S / m ⁵ ) is R = 2 × p × LU ² / S ³ (1) where p is clay (N · S / m ⁵ ). , L is the flow channel length (m) U is the flow channel cross-section peripheral length (m) S is the flow channel cross section (m ² ).

Therefore, a part of the substrate 1 is enlarged and shown in FIG.
As shown in the plan view of FIG. 17A and the vertical sectional view of FIG. 17B, the nozzle 125 has an outlet size of 40 μm and a flow path length of 0.4.
A conventional example of 3 mm and a plan view of FIG.
As shown in the vertical cross-sectional view of (b), a deep channel 6 having a channel length of 0.38 mm is formed in a pressure chamber having a length of 1.0 mm from the nozzle forming position, and a hole having a thickness of 0.05 mm is formed. Nozzle 5 on the bottom
In this embodiment having the (outlet size φ40 μ), the width of the pressure chamber is 0.8 mm, the distance from the pressure chamber to the nozzle is 6.5 mm, and this distance range is 0.8 mm to 0.8 mm.
When the flow path resistance R (N · S / m ⁵ ) is calculated by the above equation (1) for the pressure chambers 2a to 2n having the taper and inclination of 1 mm, as shown in Table 1, in Example 1 as compared with the conventional example, , The flow path resistance R of the nozzle part is reduced by about 40%,
The overall flow path resistance R has decreased by almost 50%.

Table 1 Conventional Example Example 1 Pressure chamber → Nozzle 3.2 × 10 ¹¹ 1.73 × 10 ¹¹ Nozzle 3.7 × 10 ¹² 1.19 × 10 ¹² Whole 4.0 × 10 ¹² 1.37 × 10 ¹² Example 2. 4 is a plan view of a substrate of a piezoelectric head unit showing a second embodiment of the present invention with a diaphragm removed, and FIG. 5 is a cross-sectional view taken along the line BB of FIG. 4 with the diaphragm attached. . In the second embodiment, as in the first embodiment, the substrate 1 made of photosensitive glass has a large number of pressure chambers 2a arranged side by side in a radial direction from the center end of the linear shape toward the outer circumference.
˜2n, a common ink passage 3 surrounding the pressure chambers 2a to 2n and communicating with the pressure chambers, and an ink introduction port 4 for supplying ink to the common ink passage 3 are formed by etching. Then, the high-density narrow-width pressure chamber flow passage 11 near the central ends of the pressure chambers 2a to 2n is penetrated to the back of the substrate 1, and the nozzle 5 is aligned with the through passage 11 to form the nozzle forming plate 12.
Is attached to the back surface of the substrate 1.

FIG. 6 is a diagram showing the processing steps of the substrate 1 in the second embodiment. First, the pattern mask 13 is attached to the surface of the photosensitive glass substrate 1 and the pattern mask 13 is formed.
Exposure is performed from the side (step 6-1). Then, when the pattern mask 13 is removed and an etching process is performed, the exposed portion is etched to form a recess (step 6).
-2).

Next, a pattern mask 14 for forming a pressure chamber is attached to the recessed surface of the photosensitive glass substrate 1 and exposed from the side of the pattern mask 14 (step 6-3). After the exposure, when the pattern mask 14 is removed and etched, the surface of the photosensitive glass substrate 1 is further etched,
The concave portion formed in the above step 6-2 is the photosensitive glass substrate 1
The through channel 11 is formed so as to penetrate the back surface of the (step 6-
4).

Then, on the back surface of the photosensitive glass substrate 1,
The nozzle forming body 12 is attached so that the nozzle 5 is aligned with the through flow passage 11 (step 6-5), and the vibration plate 18 is joined to the pressure chamber forming surface of the substrate 1 (step 6-6). Piezoelectric elements 19a to 19n facing the pressure chamber on the outer surface of 18
Install (step 6-7).

FIG. 7 is an explanatory view of forming the nozzle forming plate 12.

After placing the mask 16 on the processing table 15,
Nickel plating is repeatedly applied to the surface of the processing table to form a nickel layer, and then the nickel layer is removed from the processing table 15 to obtain a plated plate as an electroplated product.

The nozzle 5 can be formed on the plating plate by removing the mask 16 from the plating plate. This plating plate is used as the nozzle forming plate 12. The nozzle 5 is formed one step lower than the outer surface of the plated plate depending on the thickness of the mask 16, as shown in FIG. Therefore, when the burr 17 on the surface of the plated plate is removed and the surface is finished and polished, the nozzle 5 is not adversely affected such as cracks in the periphery.

Therefore, as compared with the conventional example shown in FIGS. 17A and 17B, as shown in the plan view of FIG. 19A and the longitudinal sectional view of FIG. 1.0
A through channel 11 having a channel length of 0.43 mm is formed in the pressure chamber in the area of mm, and the outlet dimension φ facing the through channel 11 is φ.
For Example 2 in which a nozzle forming body 12 having a thickness of 1.0 mm and having a 40 μ nozzle formed therein was attached, the width of the pressure chamber was 0.8.
mm, the distance from the pressure chamber to the nozzle is about 6.5 mm, and the distance range is defined as pressure chambers 2a to 2n with a taper slope of 0.8 to 0.1 mm in width. When R (N · S / m ⁵ ) is calculated, as shown in Table 2, in Example 2, the flow path resistance R of the nozzle portion is reduced by about 40% as compared with the conventional example, and the entire flow path is Resistance R
Has decreased by almost 50%.

Table 2 Conventional Example Example 2 Pressure chamber → Nozzle 3.2 × 10 ¹¹ 1.69 × 10 ¹¹ Nozzle 3.7 × 10 ¹² 2.39 × 10 ¹² Whole 4.0 × 10 ¹² 2.56 × 10 ¹² Example 3. 9, 10 and 11 show the overall structure of an inkjet printer according to the present invention, which incorporates the inkjet print head described above.

In each drawing, the ink jet printer includes a flat platen 20 to make it small and thin as a facsimile, plotter or bar code printer, and the recording paper not shown in the drawing includes the flat platen 20 as shown by an arrow A in FIG. Sent to.
In order to feed the recording paper correctly, the flat platen 20
Feed rollers 21 and 22 are provided in front of and behind, respectively, and a predetermined amount of feeding operation can be performed by sandwiching the recording paper between the idle rollers 23 and 24 facing each other.

A pair of carriage guides 25 and 26 are provided above the flat platen 20, and a carriage 27 is supported by the carriage guides 25 and 26 so as to be reciprocally movable in the row direction of the recording paper. Although not shown in detail in the carriage 27, a drive system is connected so that the carriage 27 can be moved to an arbitrary position in the row direction with respect to the recording paper by a driving force such as a stepping motor. Therefore, the carriage 27 can reciprocate in the direction indicated by the arrow BC in the figure.

The carriage 27 incorporates the above-mentioned ink jet print head shown in FIGS. 1 to 8, and the above-described one row of nozzles 6 is used for the flat platen 2.
It is arranged so as to face the recording paper led on the 0.

An ink cartridge 28 is provided below the flat platen 20 in order to supply ink to the ink jet print head built in the carriage 27. From the ink cartridge 28, the inlet port 5 of the print head 10 is provided. The required ink supply towards the side is provided, for example, through a flexible tube.

Further, the apparatus is provided with a cleaning unit 29 so that the nozzles of the inkjet print head do not solidify when not in use, and the carriage 27 directs the inkjet print head toward the cleaning unit 29 during non-printing. Evacuated.

In order to apply a desired driving force to the paper feeding and cleaning unit 29 described above, the feed motor 3 is used in the ink jet printer as shown in FIG.
0, and a carriage drive motor 31 for driving the above-mentioned carriage 27, each of which is provided with a feed roller 21, through a transmission mechanism (not shown).
22 and the carriage 27 are being driven.

[0049]

As described above, according to the present invention, the depth of the high-density narrow-width pressure chamber flow path near the central end portion is increased, and the substrate is removed from the bottom surface of the deep flow path. The nozzle is formed by penetrating therethrough, or the high-density narrow-width pressure chamber flow path near the central end is penetrated to the back of the substrate, and the nozzle forming plate is attached to the back surface of the substrate so that the nozzle matches the penetration flow path. The ink flow path resistance from the pressure chamber to the ink ejection port of the nozzle can be reduced by mounting the device to the ink ejection port, the speed and response of the ink ejection port from the ink ejection port can be improved, and accurate high-speed printing can be realized. The effect that it can be obtained.

[Brief description of drawings]

FIG. 1 is a plan view of a piezoelectric head unit from which a diaphragm according to a first embodiment is removed.

2 is a cross-sectional view taken along the line AA of FIG. 1 with a diaphragm attached.

FIG. 3 is a diagram showing a process of processing the substrate of FIG.

FIG. 4 is a plan view of a piezoelectric head unit with a diaphragm according to a second embodiment removed.

5 is a cross-sectional view taken along line BB of FIG. 4 with a diaphragm attached.

6 is a diagram showing a processing step of the substrate of FIG. 4;

FIG. 7 is an explanatory view of forming a nozzle forming plate.

FIG. 8 is a vertical cross-sectional view of the nozzle forming plate.

FIG. 9 is a side view of the main parts of the inkjet printer according to the present invention shown in FIGS.

FIG. 10 is a plan view of a main part of an inkjet printer having a print head according to the present invention built therein.

11 is a front view of a main part of the inkjet printer shown in FIG.

FIG. 12 is a diagram illustrating the principle of a piezoelectric head unit.

13 is a plan view of a substrate of the piezoelectric head unit of FIG. 12 from which a diaphragm is removed.

FIG. 14 is a view of FIG. 13 with a diaphragm attached.
It is a cross-sectional view taken along the line X-.

FIG. 15 is a diagram showing a step of processing a substrate.

16 is a cross-sectional view of a conventional inkjet printhead in which the piezoelectric head unit of FIG. 14 is assembled on a base.

17A and 17B are a plan view and a vertical sectional view showing an example of dimensions of each part of a conventional piezoelectric head unit.

18A and 18B are a plan view and a vertical sectional view showing an example of dimensions of each part of the piezoelectric head unit according to the first embodiment.

19A and 19B are a plan view and a vertical sectional view showing an example of dimensions of each part of the piezoelectric head unit according to the second embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2a-2n Pressure chamber 3 Common ink path 4 Ink inlet 5 Nozzle 6 Deep flow path 12 Nozzle forming plate 17 Vibration plate 18a-18n Piezoelectric element

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location B41J 2/175 8306-2C B41J 3/04 102 Z

Claims (4)

[Claims] 1. A plurality of pressure chambers, which are arranged in parallel with each other so as to radially widen toward the outer periphery from the central ends of two rows which are linearly arranged,
A common ink passage that surrounds each of the pressure chambers and communicates with the pressure chambers, a substrate having an ink inlet for supplying ink to the common ink passages, and two central rows of the pressure chambers that communicate with each other. A piezoelectric head unit having a plurality of nozzles formed so as to form a diaphragm, a diaphragm attached to the pressure chamber forming surface of the substrate, and a piezoelectric element attached to an outer surface of the diaphragm facing the pressure chamber. In the inkjet print head assembled on a table, the depth of the high-density narrow-width pressure chamber flow path near the central end portion is increased, and the nozzle is penetrated from the bottom surface of the deep flow path to the substrate. An inkjet print head characterized by being formed. 2. A plurality of pressure chambers, which are arranged in a straight line so as to widen in a radial direction from a central end portion of the two rows toward the outer periphery, and a common ink passage which surrounds each pressure chamber and communicates with the pressure chambers. A substrate having an ink inlet for supplying ink to the common ink passage, a plurality of nozzles formed so as to communicate with the central ends of the pressure chambers in the two rows, and the pressure chamber of the substrate In an inkjet printhead in which a piezoelectric head unit having a vibration plate attached to a forming surface and a piezoelectric element respectively attached to the outer surface of the vibration plate facing the pressure chamber is mounted on a base, An ink jet print head, characterized in that a high density narrow pressure chamber channel is penetrated to the back side of a substrate, and a nozzle forming plate is attached to the back side of the substrate so that the nozzles match the through channel. 3. A carriage that is capable of reciprocating in a row direction with respect to a platen holding a recording sheet, the carriage being provided with an ink jet print head, and the ink jet print head having two linear rows. A plurality of pressure chambers arranged radially in parallel with each other from the central end portion of the pressure chamber toward the outer periphery, common ink passages surrounding each pressure chamber and communicating with the pressure chambers, and ink for supplying ink to the common ink passages. A substrate on which an inlet is formed, a plurality of nozzles formed so as to communicate with the central ends of the two rows of each pressure chamber, a vibration plate attached to the pressure chamber forming surface of the substrate, and the pressure A piezoelectric head unit having piezoelectric elements attached to the outer surface of the diaphragm facing the chamber is mounted on a base to increase the flow channel depth of the high-density narrow pressure chamber flow channel near the central end. hand, An inkjet printer characterized in that the nozzle is formed by penetrating the substrate from the bottom surface of the deep channel. 4. An inkjet print head is provided on the carriage, the carriage including a carriage capable of reciprocating in a row direction with respect to a platen holding a recording sheet. The inkjet print head has two linear rows. A plurality of pressure chambers that are radially arranged from the center end portion of the ink cartridge toward the outer periphery and are arranged in parallel, a common ink passage that surrounds each pressure chamber and communicates with the pressure chambers, and an ink that supplies ink to the common ink passage A substrate having an inlet formed therein, a plurality of nozzles formed so as to communicate with the central ends of the two rows of the pressure chambers, a vibration plate attached to the pressure chamber forming surface of the substrate, and the pressure Assembling the piezoelectric head unit having a piezoelectric element attached to the outer surface of the diaphragm facing the chamber, respectively, to the base, and passing the high-density narrow pressure chamber channel near the central end portion to the back of the substrate, To match the nozzle with this through-flow hole,
An inkjet printer having a nozzle forming plate attached to the back surface of the substrate.