JP2002355960A - Ink jet recording head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet recording head exhibiting stabilized ink drop ejection performance even after continuous printing by preventing a bubble being taken into an ink ejection hole, aggregation of ink or a foreign matter from staying in the channel and stabilizing the temperature of ink in the channel. SOLUTION: In an ink jet recording head 20 where an ink reservoir 7 located between two rows of channel groups A and B is provided with an ink recovery hole 9, an ink reservoir 6A located between the channel group A and a frame 5 is provided with an ink supply hole 8A, and an ink reservoir 6B located between the channel group B and the frame 5 is provided with an ink supply hole 8B, following relations are satisfied; 0.5<=Sa/Qa<=2.5, 0.5<=Sj/Qa<=2.5, 0.5<=Sb/Qb<=2.5, 0.5<=Sj/Qb<=2.5, where Sa is the total area of the opening of the ink supply hole 8A, Sb is the total area of the opening of the ink supply hole 8B, Sj is the total area of the opening of the ink recovery hole 9, Qa is the sum of the cross-sectional area of channels 2A in the channel group A, and Qb is the sum of the cross-sectional area of channels 2B in the channel group B.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used in various printers and recorders for printing characters and images by discharging ink droplets from fine ink discharge holes, in facsimile machines, and in pattern formation in the printing and ceramic fields. The present invention relates to an ink jet recording head mounted on a recording device such as a printing machine, and more particularly to an ink jet recording head having two rows of ink ejection holes and capable of high-speed, high-quality printing.

[0002]

2. Description of the Related Art In recent years, with the spread of multimedia, a non-impact type recording device using an ink jet system or a thermal transfer system has been developed in place of the impact type recording device. It is expanding in the home sector.

[0003] Among such non-impact type printing apparatuses, a printing apparatus using an ink jet system has attracted attention for its future potential because it is easy to increase the number of gradations and colors and the running cost is low.

FIGS. 3A and 3B show an example of an ink jet recording head used in a recording apparatus utilizing an ink jet system. As shown in FIG. A plurality of grooves, both ends of which are opened, are arranged in parallel on the processed piezoelectric ceramic plate, each groove is used as an ink flow path 33, and a flow path member 31 having a partition 32 as a wall separating each groove, A driving electrode 34 formed on the lower half of the side surface of each partition 32 and an ink discharge hole 36 that is joined to the top surface of each partition 32 so as to cover each flow path 33 and communicates with each flow path 33
A sealing member 38 joined to an end of the flow path member 31 and the nozzle plate 35 to form an ink chamber 37 communicating with each of the flow paths 33; The ink supply holes 39 provided at both ends of the head 40 supply ink to the ink chambers 37 and the flow paths 33, and are provided on both side surfaces of the partition wall 32. When the drive electrode 34 is energized, the partition wall 32 is bent and displaced, and the ink in the flow path 33 is pressurized to be ejected from the ink ejection hole 36 as an ink droplet.

That is, when a voltage is applied to the driving electrodes 34 provided on both side surfaces of the partition 32, the piezoelectric ceramics forming the partition 32 undergoes shear mode deformation, whereas the partition 32 is restricted vertically. The ink in the flow path 33 is pressurized by the bending displacement of the partition wall 32 so that the ink is ejected from the ink ejection holes 36 as ink droplets. Reference numeral 30 denotes a lead wire of the driving electrode 34 (Japanese Patent Laid-Open No. 9-94952).
Reference).

[0006]

However, FIG. 3 (a)
In the conventional head 40 as shown in FIG. 2B, when the pressure in the flow path 33 is reduced, air is mixed in from the ink discharge holes 36,
Bubbles may be taken into the ink in the flow path 33 or the ink chamber 37. When the amount of the bubbles increases, the partition wall 32 is bent and displaced to perform the next ink discharge, and the flow path 3
Even if an attempt is made to pressurize the ink in the ink cartridge 3, the force is absorbed by the air bubbles and the pressure cannot be increased, so that a predetermined amount of ink droplets cannot be ejected from the ink ejection holes 36 or the ink ejection holes 36 There has been a problem that the ink cannot be discharged more.

When a lot of air bubbles are taken into the ink in the flow path 33 and the ink chamber 37, the solvent in the ink evaporates to generate an aggregate of the ink, and the aggregate of the ink is discharged. When it accumulates in the hole 36, it causes clogging,
Further, when the aggregates of the ink accumulate in the flow path 33, the flow of the ink is disturbed, and in any case, there is a possibility that the ejection failure of the ink droplet may occur.

For this reason, in a recording apparatus equipped with a conventional head 40 as shown in FIGS. 3A and 3B, printing is periodically interrupted, and ink is sucked from an ink discharge hole 36 by a pump or the like. As a result, bubbles, aggregates or foreign matter in the ink in the flow path 33 and the ink chamber 37 are removed from the flow path 33.
Cleaning operation such as removal from the ink chamber 37 is performed.
In addition to the problem that a cleaning operation is required during printing and the printing time is prolonged, in the cleaning operation, bubbles, aggregates, or foreign matters in the ink in the flow path 33 and the ink chamber 37 are removed in the flow path 33. In addition, the ink cannot be completely removed from the ink chamber 37, and there is a problem in reliability.

Further, when the conventional head 40 as shown in FIGS. 3A and 3B is continuously driven, the piezoelectric ceramic partition wall 32 that bends and displaces in a short cycle generates heat, and the ink inside the flow path 33 is heated. However, since the degree of heat generation of the partition walls 32 varies depending on the frequency of ink droplet ejection, the ejection speed of ink droplets differs for each ink ejection hole 36. However, there is a problem that the landing positions of the prints vary and the print quality is reduced.

The conventional head 40 shown in FIGS. 3 (a) and 3 (b) has only one row of flow path groups. Therefore, a similar head 40 is used to increase the printing speed and improve the image quality. Must be used in two or more rows, but in this case, the ratio of the head 40 increases, and there is a problem that the recording apparatus cannot be downsized.

As a head capable of high-speed printing and high-quality printing and capable of being miniaturized, a head having two or more rows of flow paths has been proposed.
As in the case of the conventional head 40 shown in FIG. 2B, a head capable of solving the above-mentioned problem has not been obtained.

Therefore, in order to solve these problems, there are provided two rows of flow path groups and a frame surrounding the two rows of flow path groups. An ink reservoir is provided between the ink reservoirs, and ink is supplied to the flow channels of each flow channel group from ink supply holes opened in one ink reservoir, and each of the flow channel groups is opened from an ink collection hole opened in another ink reservoir. By providing a circulation mechanism that collects the ink of the type, air bubbles and agglomerates of the ink or foreign substances mixed into the ink from the ink discharge holes are removed from the inside of the flow path, and the clogging of the ink discharge holes is eliminated. The applicant of the present application has previously proposed that the temperature of the ink flowing in the flow path be stabilized and the variation in the ejection amount and the ejection speed of the ink droplets ejected from the ink ejection holes be suppressed (Japanese Patent Application Flat 11-371687
issue).

However, although the technique proposed by the applicant of the present application has been sufficiently confirmed to obtain excellent effects as compared with the head 40 shown in FIGS. Optimal structure that can prevent clogging of the ejection holes, stabilize the temperature of ink flowing in the flow path, and suppress variations in the ejection amount and ejection speed of ink droplets ejected from the ink ejection holes Was not fully considered.

[0014]

Means for Solving the Problems Accordingly, the present inventor has proposed:
In an ink jet recording head having two rows of ink discharge holes, it is possible to prevent clogging of the ink discharge holes, and to stabilize the temperature of ink flowing in the flow path to discharge ink droplets discharged from the ink discharge holes. After repeating various studies on the optimal structure that can further reduce variations in the amount and ejection speed, the total area of the openings of the ink supply holes, the total area of the openings of the ink collection holes, The inventors have found that it is sufficient to set the sum of the areas of the cut surfaces when the flow path is cut along a plane perpendicular to the longitudinal direction to a specific range, and have reached the present invention.

That is, in the ink jet recording head of the present invention, a plurality of partition walls made of piezoelectric ceramics are juxtaposed on an insulating substrate, and two rows of flow path groups each having an ink flow path between the partition walls. A frame surrounding the path group, and one recess formed between the two rows of flow path groups and two recesses formed between the frame body and each flow path group as ink reservoirs, respectively. And a flow path member provided with a drive electrode on the side surface of each of the partition walls, and an ink ejection hole which is joined to the flow path member so as to cover the flow path and the ink reservoir and communicates with each flow path. The two ink reservoirs, which are formed between the frame body and the respective flow path groups, are provided with ink supply holes for supplying ink to the respective flow path groups. One ink reservoir formed in each of the ink tanks has an ink collection hole for collecting the ink of each channel group. The sum of the areas of the openings of the ink supply holes formed in one ink reservoir is Sa, the sum of the areas of the openings of the ink supply holes formed in the other ink reservoir is Sb, and the opening of the ink collection hole is The sum of the area of the sections is Sj, the sum of the areas of the cut surfaces when the flow path forming one flow path group is cut along a plane perpendicular to the longitudinal direction is Qa, and the flow forming the other flow path group is Qa. When the total area of the cut surfaces when the road is cut along a plane perpendicular to the longitudinal direction is Qb, 0.5 ≦ Sa / Qa ≦ 2.5 0.5 ≦ Sj / Qa ≦ 2.50 0.5 ≦ Sb / Qb ≦ 2.5 0.5 ≦ Sj / Qb ≦ 2.5.

Preferably, the sum of the area of the opening of the ink supply hole formed in the one ink reservoir (Sa) and the sum of the area of the opening of the ink recovery hole (Sj) satisfy Sa ≦ Sj, and The sum of the area of the opening of the ink supply hole (Sb) formed in the other ink reservoir and the sum of the area of the opening of the ink collection hole (Sj) satisfy the relationship of Sb ≦ Sj. Preferably, more preferably, the sum of the area of the opening of the ink supply hole formed in the one ink reservoir (Sa) and the flow path forming the one flow path group are cut by a plane perpendicular to the longitudinal direction thereof. The sum (Qa) of the areas of the cut surfaces satisfying the relationship of 0.5 ≦ Sa / Qa ≦ 1.0 and the area of the opening of the ink supply hole formed in the one ink reservoir is obtained. Sum (Sa) and the surface of the opening of the ink recovery hole Satisfy the relationship of 2.0 ≦ Sj / Sa ≦ 4.6, and the sum (Sb) of the area of the opening of the ink supply hole formed in the other ink reservoir and the other (Sb) The total sum (Qb) of the cut surfaces when the flow channels forming the flow channel group are cut along a plane perpendicular to the longitudinal direction thereof satisfies the relationship of 0.5 ≦ Sb / Qb ≦ 1.0. At the same time, the total area (Sb) of the openings of the ink supply holes formed in the other ink reservoir and the total area (Sj) of the openings of the ink collection holes are 2.0 ≦ Sj / Sb ≦ 4. .6 should be satisfied.

[0017]

Embodiments of the present invention will be described below.

FIG. 1 is a view showing an ink jet recording head according to the present invention. FIG.
(B) is a front view of (a).

The ink jet recording head 20 comprises a flow path member 15, a nozzle plate 14 and a container 17, and the flow path member 15 is formed by forming a plurality of partition walls made of piezoelectric ceramic on an insulating substrate 4 having a rectangular planar shape. 1A and 1B are juxtaposed by bonding, and an ink flow path 2 is provided between the partition walls 1A and 1B.
A, 2B, two rows of flow path groups A, B, and each flow path group A, B
And a frame 5 surrounding the ink reservoir 7 and a recess formed between the frame 5 and the channel group A. And a recess formed between the frame 5 and the flow path group B with the ink reservoir 6B.
The two ink reservoirs 6A and 6B formed between the frame 5 and the respective flow path groups A and B have respective flow path groups A and B.
Ink supply holes 8A for supplying ink to the ink supply holes 8A,
8B, a plurality of ink collecting holes 9 for collecting the ink of each of the flow path groups A and B are formed in one ink reservoir 7 formed between the two rows of the flow path groups A and B, respectively. As shown in FIG. 2, a driving electrode 3 is formed on the upper half of the side surface of each of the partition walls 1A and 1B.

The flow path member 15 includes the respective flow paths 2A and 2A.
A nozzle plate 14 is bonded to the top surfaces of the partition walls 1A and 1B and the top surface of the frame 5 by adhesive so as to cover B and the ink reservoirs 6A, 6B and 7. It has an ink ejection hole 13A communicating with each channel 2A of the group A and an ink ejection hole 13B communicating with each channel 2B of the channel group B.

The partition walls 1A and 1B are formed of a piezoelectric ceramic mainly containing lead zirconate titanate, lead zirconate lanthanum titanate, lead magnesium niobate or a mixture thereof, and have a trapezoidal shape. As shown in FIG. 2, it is polarized in the direction of the arrow. The cross-sectional area of each flow path 2 is 0.008 to 0.05.
There as about mm ^2, also in the flow path 2 is deposited a protective layer S such as silicon nitride, the drive electrodes 3 are prevented from undergoing erosion by ink.

The flow paths 2A, 2B of each flow path group A, B
Are arranged at an angle of 0.8 ° to 1.0 ° with respect to the short side of the insulating substrate 4, and the intervals between the flow paths 2A and 2B in the respective flow path groups A and B are the same. Flow path 2A of group A
And the flow path 2B of the flow path group B are provided on the same line. Thus, as shown in FIG. 1 (b), the two ink discharge holes 13A communicating with the flow paths 2A in one flow path group A are connected to two adjacent flow paths 2B in the other flow path group B. It is possible to dispose the ink droplets between the ink discharge holes 13B. If ink droplets are discharged from the ink discharge holes 13A, 13B corresponding to the respective flow path groups A, B, the dot interval can be reduced, and the head 20 can be moved. It is possible to provide the head 20 capable of high-speed printing and high-quality printing without increasing the size.

The nozzle plate 14 is made of molybdenum or Ni-Fe.
A lid 10 made of a metal such as a base alloy and a nozzle 12 made of a resin such as a polyimide resin. The lid 10 has an ink guide hole 11 communicating with each flow path 2. An ink ejection hole 13 communicating with the ink guide hole 11 is opened.

Reference numeral 21 denotes a driver IC mounted on the insulating substrate 4 outside the frame 5, and is configured to supply current to each of the driving electrodes 3 via a lead 16 wired on the insulating substrate 4. .

Further, a container 17 is joined to a lower portion of the insulating substrate 4. In the container 17, ink is collected from an ink supply passage 18 for guiding ink to the ink supply hole 8 and an ink collection hole 9. An ink collection passage 19 is formed, and ink supplied from an ink tank (not shown) to the ink supply passage 18 of the container 17 is supplied to each of the ink supply holes 8A and 8A.
B to each of the ink reservoirs 6A and 6B,
The ink sent to A is sent to the ink reservoir 7 through the channel 2A of the channel group A, and the ink sent to the ink reservoir 6B is passed to the ink reservoir 7 through the channel 2B of the channel group B. The ink is sent to the ink recovery passage 19 from the ink recovery hole 9.

In the ink jet recording head 20 of the present invention shown in FIGS. 1A and 1B, one ink reservoir 6A is provided.
The sum of the areas of the openings of the ink supply holes 8A formed in the ink supply holes 8A is defined as Sa.
The sum of the areas of the openings of B is Sb, the sum of the areas of the openings of the ink collection holes 9 is Sj, and the flow path 2 in one flow path group A is
Qa is the sum of the areas of the cut surfaces when A is cut along a plane perpendicular to the longitudinal direction, and the flow path 2B in the other flow path group B
Is defined as satisfying the following relationship, where Qb is the total area of the cut surface when Q is cut along a plane perpendicular to the longitudinal direction.

0.5 ≦ S / Qa ≦ 2.5 0.5 ≦ Sj / Qa ≦ 2.5 0.5 ≦ Sb / Qb ≦ 2.5 0.5 ≦ Sj / Qb ≦ 2.5 The principle of ejecting ink droplets of the ink jet recording head 20 shown in FIGS. 1A and 1B will be described. In addition,
Since the flow path group A and the flow path group B have the same structure, description will be made with reference to the cross-sectional views shown in FIGS.

First, the ink jet recording head 20
To discharge more ink droplets, first, an ink such as a pigment type oil-based ink, a water-based dye ink, or an ultraviolet curable ink is used as the ink in the container 1 by a circulation mechanism (not shown).
The ink supplied to the ink supply passage 18 and sent to the ink supply hole 8A is supplied to the ink reservoir 6A and the passages 2 of the passage group A.
A, the ink sent to the ink reservoir 7 and the ink supplied to the ink supply hole 8B are sent to the ink reservoir 7 through the ink reservoir 6B and each of the flow paths 2B of the flow path group B. It is circulated so as to be collected in the collection passage 19. In this state, for example, as shown in FIG.
When a positive voltage is applied to the driving electrodes 3c and the driving electrodes 3h and 3i, and a negative voltage is applied to the driving electrodes 3a, 3d, 3g and 3j, the partition walls 1a and 1b are bent and displaced toward the flow path 2a. Since 1d and 1e are bent and displaced toward the flow path 2d, the ink filled in the flow paths 2a and 2d can be pressurized to discharge ink droplets from the ink discharge holes 9. Next, the driving electrodes 3a to 3d, 3g to 3
When the current to j is cut off, the partition walls 1a,
1b, 1d, 1e return to the original shape by the elastic action,
As a result of the pressure reduction in the flow paths 2a and 2d, the ink reservoirs 6A and 6A
When the introduction of the ink is started from B, and the voltage is applied by reversing the positive and negative of the driving electrodes 3a to 3d and 3g to 3j, as shown in FIG. 1b bends outwardly with respect to the flow path 2a and the partition walls 1d and 1e bend outwardly with respect to the flow path 2d, so that the pressure inside the flow paths 2a and 2d is further reduced and the ink is filled. Become. And the driving electrodes 3a to 3
When the energization of d, 3g to 3j is cut off, the partition walls 1a, 1b, 1d, 1e which have been bent and displaced return to their original shapes by the elastic action, and enter the stage of discharging the next ink droplet. By repeating these operations sequentially,
Ink droplets can be ejected continuously, and ink droplets can be ejected from the ink ejection holes 13 of each of the flow path groups A and B by repeating the above-described operation in each of the flow path groups A and B.

According to the ink jet recording head 20 of the present invention, the inside of each flow path 2A of the flow path group A and the flow path group B
As described above, a slow flow of ink is generated and circulated in each of the flow paths 2B, so that the bubbles from the ink discharge holes 13A and 13B due to the malfunction of the head 20 in the narrow flow paths 2A and 2B as described above. Enter, aggregates of ink are formed, or foreign matter in the ink is
Even if it is interposed in the inside of the flow path 2B, these bubbles, aggregates of ink, foreign matter, etc. are prevented from staying in the flow paths 2A, 2B, and the ink discharge holes 13A, 13B are clogged or ink droplets are discharged. The performance can be prevented from deteriorating.

Therefore, according to the head 20 of the present invention, it is not necessary to suction ink from the ink ejection holes 36 as in the conventional head 40 shown in FIGS. It can be performed continuously, and can also be made highly reliable such that foreign substances larger than the diameter of the ink ejection holes 13A and 13B can be removed.

In addition, according to the head 20 of the present invention, since the slow ink flow is generated and circulated, the partition walls 1A and 1B made of piezoelectric ceramics generate heat with the continuous ejection of ink droplets. Even if it does, the temperature of the ink in the flow paths 2A, 2B can be prevented from becoming too high, and the temperature of the ink flowing in the flow paths 2A, 2B can be kept constant. It is possible to eject ink droplets at a constant speed without changing the viscosity of the ink inside, and it is possible to prevent a decrease in printing quality as seen with the conventional head 40 due to long-term use.

By the way, air bubbles, agglomerates of ink, foreign matters and the like interposed in the ink in the flow paths 2A and 2B are stably recovered from the ink recovery holes 9 and the flow paths 2A and 2B.
To keep the temperature of the ink inside, as described above,
The sum of the areas of the openings of the ink supply holes 8A formed in the one ink reservoir 6A is Sa, the sum of the areas of the openings of the ink supply holes 8B formed in the other ink reservoir 6B is Sb, and the ink collection holes 9 are formed. Is the sum of the areas of the openings, Sj is the sum of the areas (cross-sectional areas) of the cut surfaces when the flow path 2A in one flow path group A is cut along a plane perpendicular to the longitudinal direction, and Qa is the flow of the other flow path. When the sum total of the area (cross-sectional area) of the cut surface when the flow path 2B in the road group B is cut along a plane perpendicular to the longitudinal direction is defined as Qb, the following relationship is satisfied. is important.

0.5 ≦ S / Qa ≦ 2.5 0.5 ≦ Sj / Qa ≦ 2.5 0.5 ≦ Sb / Qb ≦ 2.5 0.5 ≦ Sj / Qb ≦ 2.5 The sum of the areas (Sa, Sb) of the ink supply holes 8A, 8B and the sum of the areas (Sj) of the ink recovery holes 9 are determined by the cutoff of the flow paths 2A, 2B in one of the flow path groups A, B. When the sum of the areas (Qa, Qb) becomes extremely narrow, the flow rate of ink in each of the flow paths 2A, 2B of one of the flow path groups A, B is small, and each of the flow paths 2
A, 2B, ink bubbles, ink aggregates, foreign matter, and the like intervening in the ink cannot be efficiently washed away, causing clogging of the ink ejection holes 13A, 13B,
This is because it is difficult to keep the temperature of the ink flowing in the ink supply holes A and 2B constant, and the ejection speed of the ink droplets fluctuates to deteriorate the printing quality. Ratio of the total area (Sa, Sb) of the sections and the total area (Qa, Qb) of the cross-sectional areas of the flow paths 2A, 2B in one of the flow path groups A, B, or the opening of the ink recovery hole 9. (Sj) and the sum of the cross-sectional areas of the flow paths 2A and 2B in one of the flow path groups A and B (Q
a, Qb) are Sa / Qa <0.5, respectively.
Sj / Qa <0.5, Sb / Qb <0.5, Sj / Qb
This is because when <0.5, this tendency becomes remarkable.

Further, one of the ink supply holes 8A,
The sum of the areas of the openings 8B (Sa, Sb) and the sum of the areas of the openings of the ink recovery holes 9 (Sj) are the cross-sectional areas of the flow paths 2A, 2B in one of the flow path groups A, B. When the total sum (Qa, Qb) becomes extremely wide, the flow path 2A,
2B, the flow rate of the ink becomes excessive, and the ink overflows from the ink ejection holes 13A, 13B to the surface of the nozzle plate 14, which may hinder the ejection of the ink droplets. Ratio of the sum of the areas of the openings (Sa, Sb) and the sum of the cross-sectional areas (Qa, Qb) of the flow paths 2A, 2B in one of the flow path groups A, B, or the opening of the ink recovery hole 9 Sum of area of part (S
j) and flow path 2 in one of flow path groups A and B
The ratios of the cross-sectional areas A, 2B to the sum (Qa, Qb) are 2.5 <Sa / Qa, 2.5 <Sj / Qa, 2.
This is because when 5 <Sb / Qb and 2.5 <Sj / Qb, this tendency becomes remarkable.

Preferably, the sum of the areas of the openings of the ink supply holes 8A formed in the one ink reservoir 6A (S
a) and the sum of the areas of the openings of the ink collection holes (Sj) are:
The relationship of Sa ≦ Sj and the sum of the area of the opening of the ink supply hole 8B (Sb) formed in the other ink reservoir 6B and the sum of the area of the opening of the ink collection hole (Sj) satisfy the relationship of Sb ≦ Sj. It is good to meet.

That is, one of the ink supply holes 8A,
8B, the sum of the areas of the openings (Sa, Sb) and the sum of the areas of the openings of the ink recovery holes 9 (Sj) are S, respectively.
By satisfying the relationship of a ≦ Sj and Sb ≦ Sj,
The flow rate of the ink in the ink recovery hole 9 is determined by the ink supply holes 8A,
8B, the flow rate of the ink from the ink supply holes 8A, 8B to the ink recovery hole 9 can be constantly stabilized in each of the flow paths 2A, 2B. This is because they can be generated.

However, the total area (Sj) of the openings of the ink recovery holes 9 and one of the ink supply holes 8A, 8
B and the ratio (Sj) to the sum of the areas of the openings (Sa, Sb)
/ Sa, Sj / Sb) becomes extremely large, and if the total area (Sa, Sb) of the openings of either one of the ink supply holes 8A, 8B becomes too large, the ink from the ink supply holes 8A, 8B becomes large. The outflow of ink from the ink recovery hole 9 becomes too large with respect to the inflow of ink, and the flow paths 2A, 2A
The pressure in B decreases and air is drawn in from the ink ejection holes 13A and 13B communicating with the flow paths 2A and 2B. In particular, in the flow path group A, 1.0 <Sa / Qa, 4.6 <Sj / Sa. , This tendency becomes remarkable, and in the channel group B,
When 0 <Sb / Qb and 4.6 <Sj / Sb, this tendency becomes remarkable.

Therefore, the sum of the areas of the openings of the ink supply holes 8A (Sa) and the sum of the areas of the openings of the ink recovery holes 9 (Sj) satisfy the relationship of Sa ≦ Sj. In such a configuration, the ratio of the total area (Sa) of the opening of one ink supply hole 8A to the total cross-sectional area (Qa) of the flow path 2A in one flow path group A is 0. .5
≦ Sa / Qa ≦ 1.0 and the ink collection hole 9
The ratio of the sum of the areas of the openings (Sj) to the sum of the openings (Sa) of the one ink supply hole 8A is 2.0 ≦ Sj.
/Sa≦4.6, and the sum of the area of the opening of the other ink supply hole 8B (Sb) and the sum of the area of the opening of the ink recovery hole 9 (Sj) satisfy the relationship of Sb ≦ Sj. Is satisfied, the other ink supply hole 8
The ratio of the total area (Sb) of the area of the opening of B to the total area (Qb) of the cross-sectional area of the flow path 2B in the other flow path group B is:
0.5 ≦ Sb / Qb ≦ 1.0, and the ratio of the total area (Sj) of the openings of the ink recovery holes 9 to the total area (Sb) of the openings of the other ink supply holes 8B is: 2.0
.Ltoreq.Sj / Sb.ltoreq.4.6. Furthermore, in order to stabilize the flow of ink in the flow paths 2A and 2B in each of the flow path groups A and B, it is preferable to set the Sa flow path A side.
/ Qa and Sj / Sa and Sb on the channel group B side
It is desirable to make the values of / Qb and Sj / Sb the same.

Next, a method of manufacturing the ink jet recording head 20 shown in FIGS. 1A and 1B will be described.

First, a ceramic plate or a glass plate is prepared as the insulating substrate 4. Although the type of the ceramic plate is not particularly limited, for example, alumina, zirconia,
Insulating ceramics containing forsterite, zircon or the like as a main component are preferred.

The ink supply holes 8 are formed at predetermined positions on the insulating substrate 4 by laser processing such as a carbon dioxide gas laser.
A, 8B and an ink recovery hole 9 are respectively formed, and a piezoelectric ceramic plate polarized in the thickness direction is placed on a predetermined position between the ink supply hole 8A and the ink supply hole 8B on the insulating substrate 4 by an epoxy or the like. Paste with the adhesive. However, when piercing the ink supply holes 8A, 8B and the ink recovery hole 9, 0.5 ≦ Sa according to the cross-sectional area of the flow paths 2A, 2B.
/Qa≦2.5, 0.5 ≦ Sj / Qa ≦ 2.5, 0.5
Sb / Qb ≦ 2.5 and 0.5 ≦ Sj / Qb ≦ 2.5.

Next, using a surface grinder, the center of the short side of the piezoelectric ceramic plate is cut out along the long side direction to expose the ink recovery holes 9, and then both sides of the two rows of piezoelectric ceramic plates are further removed. A tapered surface is formed by notching with a surface grinder, and the shape is made trapezoidal. Then, a plurality of grooves serving as flow paths 2A and 2B are juxtaposed on two rows of piezoelectric ceramic plates using a diamond blade. At this time, the partitioning wall is the partition 1
A, 1B.

Next, a metal film made of aluminum, palladium, nickel, gold, copper, or the like is formed while the insulating substrate 4 is inclined in the longitudinal direction by film forming means such as a vapor deposition method, a sputtering method, an ion plating method, and a CVD method. Is applied to the surface of the insulating substrate 4, the top surfaces, the slopes of the partition walls 1A and 1B, a part of the side surface along the top surface from both ends, and the bottom of both ends of the flow paths 2A and 2B. By selectively removing the metal film deposited on the slope and the insulating substrate 4 from the top surface with a laser or the like, the metal film remaining from the upper half of the side surface of each of the partition walls 1A and 1B to the bottom of both ends is used for driving. The electrodes 3 are used as insulating substrates 4 from the bottoms of both ends of the flow paths 2A and 2B.
A pattern of the lead 16 is formed upward, and a protective film S such as silicon nitride is applied to the driving electrode 3 and the lead 16 by the film forming means.

Thereafter, the frame 5 is air-tightly bonded to the insulating substrate 4 with an adhesive such as epoxy so as to surround the partition walls 1A and 1B, the ink supply holes 8A and 8B, and the ink recovery hole 9. .

Then, the lid 10 made of a metal such as a Ni—Fe alloy or molybdenum is attached to the ink guide holes 11A, 13A.
B is bonded to the top surfaces of the partition 1 and the frame 5 with an adhesive such as epoxy so that the center of B coincides with the center in the width direction of each of the flow paths 2A and 2B. The nozzle portion 12 made of a resin such as a resin is joined with an epoxy-based adhesive or the like.

Thereafter, outside the frame 5, the driver IC 15 is mounted on the insulating substrate 4 on which the lead wire 16 is formed, and the wire is connected through a reflow furnace. Then, the nozzle is formed by laser processing such as excimer laser. Ink ejection holes 13A, 13B communicating with the ink guide holes 11A, 11B in the portion 12;
And a container 17 provided with an ink supply passage 18 and an ink recovery passage 19 below the insulating substrate 4 is hermetically bonded with an epoxy-based adhesive or the like.

As described above, in the above-described embodiment, an example was described in which ink droplets were ejected while circulating ink at all times. However, ink droplets are normally ejected with ink circulation stopped, and ink droplets are ejected. If the discharge performance is reduced,
When high-speed printing or continuous printing is performed, ink may be circulated as necessary.

The present invention is not limited to those shown in FIGS. 1 (a) and 1 (b), and it is needless to say that modifications and improvements may be made without departing from the gist of the present invention.

[0049]

(Embodiment 1) The ink jet recording head 20 shown in FIGS. 1A and 1B will be specifically described.

First, as the insulating substrate 4, 65 mm × 28
A 1 mm × 1 mm alumina ceramic plate was used, and a 1.3 mm × 1.5 mm round and long ink recovery hole 9 was formed in the center of the short side of the insulating substrate 4 along the long side direction using a carbon dioxide laser. Six holes were formed at intervals, and three ink supply holes 8A and 8B each having a 1.3 mm × 1.5 mm round hole were formed at equal intervals with a carbon dioxide laser with the ink recovery hole 9 interposed therebetween. . The offset between the ink supply holes 8A and 8B and the ink recovery hole 9 in the short side direction is 6.5 m.
m.

Next, four piezoelectric ceramic plates each having a plate shape of 10 mm × 8 mm × 0.5 mm and composed mainly of lead zirconate titanate polarized in the thickness direction are placed in the ink supply holes 8A and the ink supply holes 8A. It is arranged in a straight line with the hole 8B and attached with an epoxy adhesive, and then the center of the short side of the piezoelectric ceramic plate is cut out along the long side direction using a surface grinder to expose the ink collecting hole 9. After that, both sides of the two rows of piezoelectric ceramic plates are further cut out by a surface grinder to form a taper surface having an angle of 60 ° with the insulating substrate 4,
The shape was made trapezoidal, and then the upper surface of the piezoelectric ceramic plate was ground so that the height became 0.45 mm.

Thereafter, a diamond blade having a thickness of 70 μm was used, and 0.808 ° with respect to the short side of the insulating substrate 4.
With a depth of 0.4
By forming 284 channels 2A and 2B at 5 mm and a pitch of 0.14 mm, respectively, two rows of channel groups A and B are formed.
Was formed.

Next, aluminum is deposited by vacuum evaporation while the insulating substrate 4 is inclined in the longitudinal direction, and evaporation is performed again with the inclined direction reversed, whereby the flow paths 2A, 2B
Inside, the aluminum atoms going straight from the evaporation source are shielded by the partition walls 1A and 1B adjacent to each other,
The surface of the insulating substrate 4 and the partition walls 1A, 1B, except for the lower half of the center of the partition walls 1A, 1B and the bottom of the center of the flow paths 2A, 2B.
An aluminum film is formed on the top surface, the slope, and a part of the side surface along both ends from the top surface of 1B and the bottoms of both ends of the flow paths 2A and 2B.

Thereafter, the top surfaces of the partition walls 1A and 1B are polished,
Further, the aluminum film on the slopes of the partition walls 1A and 1B is YA
The drive electrode 3 is formed by removing with the G laser, and the aluminum film continuously formed on the insulating substrate 4 from the drive electrode 3 at the bottom of both ends of the flow paths 2A and 2B is similarly formed with the YAG laser. By dividing, the pattern of the lead wire 16 is formed, and the flow paths 2A, 2B
Was coated with a protective film S of silicon nitride on the inner wall surface by sputtering.

Then, a molybdenum frame 5 having an outer shape of 50 × 22 mm, an inner shape of 42 × 16 mm, and a thickness of 0.45 mm is inserted into each of the partition walls 1A and 1B and the ink supply holes 8.
A, 8B and the ink collecting hole 9 are hermetically bonded on the insulating substrate 4 with an epoxy-based adhesive to form a recess formed by the frame 5 and the flow path group A into the ink reservoir 6A and the frame. The concave portion formed by 5 and the flow channel group B was an ink reservoir 6B, and the concave portion formed between the two rows of the flow channel groups A and B was an ink reservoir 7.

On the top surfaces of the frame 5 and the partition walls 1A and 1B, an ink guide having an outer shape of 50 mm × 22 mm × 0.07 mm and having a diameter of about 60 μm communicating with the flow paths 2A and 2B is provided. A molybdenum lid 10 having holes 11A and 11B is joined with an epoxy-based adhesive, and an outer shape of 50 mm × 14.5 mm × 0.05 is further placed on the lid 10.
The nozzle part 12 made of a polyimide resin having a plate shape of mm was joined with an epoxy adhesive.

Next, the lead wire 1 formed on the insulating substrate 4
6, a driver IC 15 is mounted thereon, connected through a reflow furnace, and a container 17 having an ink supply passage 18 and an ink recovery passage 19 below the insulating substrate 4 is bonded with an epoxy-based adhesive. The ink jet recording head 20 of the present invention shown in FIGS. 1A and 1B is manufactured by piercing the nozzle portion 12 with ink ejection holes 13A and 13B having a diameter of about 28 μm communicating with the ink guide holes 11A and 11B. did.

The ink jet recording head 20
, The sum of the areas of the openings of the ink supply holes 8A formed in one ink reservoir 6A is Sa, and the other ink reservoir 6B
Is the sum of the areas of the openings of the ink supply holes 8B, Sj is the sum of the areas of the openings of the ink recovery holes 9, and the flow path 2A in one flow path group A is a plane perpendicular to the longitudinal direction. The sum of the area (cross-sectional area) of the cut surface when cut at Qa is Qa, and the area (cross-sectional area) of the cut surface when the flow path 2B of the other flow path group B is cut at a plane perpendicular to the longitudinal direction. )
Is the sum of Qb, Sa / Qa = 0.53, Sj /
Qa = 1.06, Sb / Qb = 0.53, Sj / Qb =
1.06.

Then, using the obtained head 20, one of the plurality of ink ejection holes 13A has one of the ink ejection holes 1A.
Focusing on 3A, an experiment was performed to measure the ejection speed of ink droplets continuously ejected from the ink ejection holes 13A and to check the number of ink droplet ejection failure locations during continuous printing.

The ejection speed of the ink droplet is 100 at 5 kHz.
The ink droplets ejected from the same ink ejection hole 13A are photographed at regular intervals by a high-speed camera while continuously ejecting the ink droplets 000 times, and the ejection of the ink droplet is performed based on the distance between the ink ejection hole 13A and the ink droplet. The speed was derived.

In addition, the number of defective ink droplet ejections during continuous printing is determined by the number of ink ejection holes 13A,
The printing paper fixed on a flat table is reciprocated in the main scanning direction by numerical control while being fixed to the recording apparatus so that the 13B column is perpendicular to the main scanning direction. By moving a certain amount in the direction,
A monochrome test pattern composed of 360 dpi lines, a lattice pattern, a solid portion, characters, and the like is printed, and the printed test pattern is observed with a microscope every 100 cm ² .
The number of places where printing was determined to be defective due to ejection of ink droplets, such as non-adhesion of ink droplets, significant displacement, and attachment of unnecessary ink droplets, were counted.

In these experiments, the ink supply holes 8 were used.
The ink supplied from A is supplied to the ink reservoir 6A and the channel 2A of the channel group A, and the ink supplied from the ink supply hole 8B is supplied to the ink reservoir 6B and the channel 2B of the channel group B, respectively. The ink droplets were ejected while circulating the ink so that the ink collected in 7 was collected from the ink collection hole 9.

For comparison, the ink supply holes 8A, 8A
A head similar to the ink jet recording head shown in FIG. 1 was prepared except that B and the ink recovery hole 9 were not provided, and the same experiment was performed.

Table 1 shows the ejection speeds of ink droplets continuously ejected from the same ink ejection hole 13A, and Table 2 shows the number of ink droplet ejection failure locations in continuous printing.

[0065]

[Table 1]

[0066]

[Table 2]

As a result, as can be seen from Table 1, the head 20 of the present invention has a more stable ink droplet ejection speed than the head of the comparative example. However, it can be seen that there are few ink droplet ejection defects.

When the reason for this was confirmed, in the head 20 of the present invention, since the ink in each of the flow paths 2A and 2B was circulated, the temperature of the ink in the flow paths 2A and 2B was almost constant, and Since the viscosity of the droplet is stable, the ejection speed of the ink droplet can be kept constant. In continuous printing, the temperature of the ink in the flow paths 2A and 2B is almost constant, and the viscosity of the ink droplet is stable. It is considered that the ejection failure of ink droplets did not increase due to the fact that air bubbles, ink aggregates, foreign matters, and the like hardly stayed in the ink in the flow paths 2A and 2B.

As a result, it can be seen that the head 20 of the present invention is a high-performance head capable of stably ejecting ink droplets with a small displacement of the ink droplet landing position. (Embodiment 2) Next, the size and number of the ink supply holes 8A and 8B and the ink recovery holes 9 of the ink jet recording head 20 shown in FIGS. 1A and 1B are changed, and the ink supply holes 8A in the ink reservoir 6A are changed. Sum of the area of the opening of the (Sa)
Ratio (Sa / Qa) to the total area (Qa) of the cut surface when the flow path 2A of the flow path group A is cut along a plane perpendicular to the longitudinal direction, and the ink supply hole 8 in the ink reservoir 6B.
B, the sum of the areas of the openings (Sb), and the flow path 2 of the flow path group B
B is a ratio (Sb / Qb) to the total area of the cut surface (Qb) when the B is cut along a plane perpendicular to the longitudinal direction, and the total area (Sb) of the opening of the ink recovery hole 9 in the ink reservoir 7.
j) and the ratio (Sj / Qa) of the total area (Qa) of the cut surfaces when the flow path 2A of the flow path group A is cut along a plane perpendicular to the longitudinal direction, and the ink collection hole in the ink reservoir 7 9 (Sj) and the ratio (Sj / Qb) of the total area (Qb) of the cut surfaces when the flow path 2B of the flow path group B is cut along a plane perpendicular to the longitudinal direction. ), The total area of the opening of the ink supply hole 8A in the ink reservoir 6A (Sa), and the total area of the opening of the ink collection hole 9 (S
j), and the ratio (Sj) of the sum of the areas of the openings of the ink supply holes 8B in the ink reservoir 6B (Sb) and the sum of the areas of the openings of the ink collection holes 9 (Sj).
j / Sb), the number of ink droplet ejection failure locations during continuous printing was measured.

The results are as shown in Table 3.

[0071]

[Table 3]

As a result, the total area (Sa) of the openings of the ink supply holes 8A in the ink reservoir 6A and the cut surface obtained when the flow path 2A of the flow path group A is cut along a plane perpendicular to the longitudinal direction. (Sa / Qa) with the total area (Qa)
Is 0.5 ≦ Sa / Qa ≦ 2.5, the sum of the areas of the openings of the ink supply holes 8B in the ink reservoir 6B (Sb),
The ratio (Sb) to the total area (Qb) of the cut surface area when the flow path 2B of the flow path group B is cut along a plane perpendicular to the longitudinal direction thereof
/ Qb) is 0.5 ≦ Sb / Qb ≦ 2.5, the sum of the areas of the openings of the ink recovery holes 9 (Sj), and the flow path 2A of the flow path group A is a plane perpendicular to the longitudinal direction. The ratio (Sj / Qa) with respect to the total area (Qa) of the cut surface when cut by (5) is 0.5 ≦ Sj / Qa ≦ 2.5, and the total area (Sj) of the openings of the ink collecting holes 9. And the ratio (Sj / Qb) of the total area (Qb) of the cut surfaces when the flow path 2B of the flow path group B is cut along a plane perpendicular to the longitudinal direction is 0.5 ≦ Sj / Q.
In the case of b ≦ 2.5, the number of defective ink droplet discharge spots is 500 or less even after continuous printing for 30 minutes. It can be seen that a print is obtained.

In particular, the total area (Sj) of the openings of the ink recovery holes 9 is the total area (Sa) of the openings of the ink supply holes 8A and the total area (Sb) of the openings of the ink supply holes 8B. When it becomes larger, each ink supply hole 8A,
8B to the ink collecting hole 9, the flow of the ink is smooth, and the ink supply hole 8 in the ink reservoir 6 </ b> A is formed.
A total (Sa) of the area of the opening of A and the flow path 2 of the flow path group A
The sum (Qa) of the cross-sectional areas of A is 0.5 ≦ Sa / Qa ≦
1.0, the sum of the areas of the openings of the ink supply holes 8B in the ink reservoir 6B (Sb),
The sum total (Qb) of the cross-sectional areas of the flow paths 2B of the flow path group B is 0.
The relationship of 5 ≦ Sb / Qb ≦ 1.0 is satisfied, and the sum of the areas of the openings of the ink collecting holes 9 in the ink reservoir 7 (S
j) and the total area (Sa) of the openings of the ink supply holes 8A in the ink reservoir 6A is 2.0 ≦ Sj / Sa ≦
4.6, the sum of the areas of the openings of the ink recovery holes 9 in the ink reservoir 7 (Sj) and the sum of the areas of the openings of the ink supply holes 8B in the ink reservoir 6B (Sb).
Satisfying the relationship of 2.0 ≦ Sj / Sb ≦ 4.6, it is possible to reduce the number of defective ink droplet ejections to 300 or less even after continuous printing for 30 minutes, and to further reduce the number of defective printings. It can be seen that prints of even better quality can be obtained.

[0074]

As described above in detail, in the ink jet recording head of the present invention, a plurality of partitions made of piezoelectric ceramics are juxtaposed on an insulating substrate, and two rows of ink are provided between the partitions. A road group, and a frame surrounding each flow path group, and one recess formed between the two rows of flow path groups and two recesses formed between the frame body and each flow path group. Each of the recesses serves as an ink reservoir, and a side surface of each partition wall is provided with a flow channel member having a driving electrode, and is joined to the flow channel member so as to cover the flow channel and the ink reservoir, and communicates with each flow channel. A nozzle plate having ink discharge holes, and two ink reservoirs formed between the frame and the respective flow path groups are provided with ink supply holes for supplying ink to the respective flow path groups. In one ink reservoir formed between the flow path groups in the row, an ink for collecting ink of each flow path group is provided. A recovery hole is provided, and the sum of the areas of the openings of the ink supply holes formed in one ink reservoir is Sa, and the sum of the areas of the openings of the ink supply holes formed in the other ink reservoir is Sb. The sum of the areas of the openings of the holes is Sj, the sum of the areas of the cut surfaces obtained by cutting one of the flow channels forming the flow channel group along a plane perpendicular to the longitudinal direction is Qa, and the other is the flow channel group. Qb is the sum of the areas of the cut surfaces when the flow path to be formed is cut along a plane perpendicular to the longitudinal direction.
Where 0.5 ≦ Sj / Qa ≦ 2.5 0.5 ≦ Sj / Qa ≦ 2.5 0.5 ≦ Sb / Qb ≦ 2.5 0.5 ≦ Sj / Qb ≦ 2.5 Is satisfied, it is possible to remove air bubbles, agglomerates of ink or foreign matters taken into the ink in the flow path, prevent clogging of the ink discharge holes, and reduce the amount of ink flowing in the flow path. Since the temperature can always be kept constant, the viscosity of the ink can be stabilized, and printing of excellent quality can be performed even if continuous printing is performed over a long period of time to prevent variations in the ejection amount and ejection speed of ink droplets. Obtainable.

In particular, in the head of the present invention, the total area (Sa) of the openings of the ink supply holes formed in the one ink reservoir and the total area (Sj) of the openings of the ink collection holes.
Is Sa ≦ Sj, and the sum of the area of the opening of the ink supply hole (Sb) formed in the other ink reservoir and the sum of the area of the opening of the ink recovery hole (Sj) are in a relationship of Sb ≦ Sj. And the sum of the areas of the openings of the ink supply holes formed in the one ink reservoir (S
a) and the sum of the areas of the cut surfaces when the flow paths forming one of the flow path groups are cut along a plane perpendicular to the longitudinal direction thereof (Q
a) satisfies the relationship of 0.5 ≦ Sa / Qa ≦ 1.0, and the sum (Sa) of the area of the opening of the ink supply hole formed in the one ink reservoir and the ink collection hole. The sum of the areas of the openings (Sj) is 2.0 ≦ Sj / Sa ≦
4.6, and the sum (Sb) of the area of the opening of the ink supply hole formed in the other ink reservoir and the flow path forming the other flow path group are perpendicular to the longitudinal direction. The sum total (Qb) of the areas of the cut surfaces when cut on a flat surface is
In addition to satisfying the relationship of 0.5 ≦ Sb / Qb ≦ 1.0, the total area (Sb) of the openings of the ink supply holes formed in the other ink reservoir and the area of the openings of the ink recovery holes Sum (Sj) of 2.0 ≦ Sj / Sb ≦ 4.6
By satisfying the relationship, the ink flow becomes particularly smooth and difficult to stagnate, so that the temperature of the ink in the flow path is further stabilized, and the aggregates and foreign substances of the ink from the flow path are further reduced. Can be reliably removed, resulting in excellent prints with less ink droplet ejection failures.
In addition, the stability of printing quality in continuous printing can be particularly excellent.

[Brief description of the drawings]

FIGS. 1A and 1B are views showing an inkjet recording head according to the present invention, in which FIG.
Is a plan view thereof.

FIGS. 2A and 2B are diagrams for explaining a driving principle of an ink jet recording head according to the present invention.

FIG. 3 is a view showing a conventional ink jet recording head.
(A) is a perspective view in which a part is partially broken, and (b) is a cross-sectional view taken along line XX of (a).

[Explanation of symbols]

1A, 1B: Partition wall 2A, 2B: Channel 3: Drive electrode 4: Insulating substrate 5: Frame 6A, 6B, 7: Ink reservoir 8A, 8B: Ink supply hole 9: Ink recovery hole 10: Lid 11A, 11B: ink guide hole 12: nozzle part 13A, 13B: ink discharge hole 1
4: Nozzle plate 15: Flow path member 16: Lead wire 17: Container 18: Ink supply path 19: Ink recovery path 20: Ink jet recording head 21: Driver IC 21: Flow path member 22: Partition wall 23: Flow path 24: Drive Electrode for use 25: Nozzle plate 26: Ink ejection hole 27: Ink chamber 28: Sealing member 29: Ink supply hole 30: Lead line 40: Ink jet recording head

Claims (3)

[Claims] 1. A frame body in which a plurality of partition walls made of piezoelectric ceramics are arranged on an insulating substrate, and two rows of flow path groups each having an ink flow path between the partition walls are arranged in parallel. And one recess formed between the two rows of the flow channel groups and two recesses formed between the frame and each flow channel group serve as ink reservoirs, respectively. A flow path member provided with a driving electrode, and a nozzle plate having an ink ejection hole connected to the flow path member so as to cover the flow path and the ink reservoir and communicating with each flow path. Two ink reservoirs formed between the frame and each flow path group are provided with ink supply holes for supplying ink to each flow path group, and one ink formed between the two rows of flow path groups. Each reservoir has an ink collection hole for collecting ink in each channel group, and is formed in one ink reservoir The sum of the areas of the openings of the ink supply holes to be formed is Sa, the sum of the areas of the openings of the ink supply holes formed in the other ink reservoir is Sb, and the sum of the areas of the openings of the ink collection holes is Sj. The sum of the areas of the cut surfaces when the flow paths forming the flow path group are cut along a plane perpendicular to the longitudinal direction is Qa, and the flow path forming the other flow path group is a plane perpendicular to the longitudinal direction. 0.5 ≦ S / Qa ≦ 2.5 0.5 ≦ Sj / Qa ≦ 2.5 0.5 ≦ Sb / Qb ≦ 2.5, where Qb is the sum of the areas of the cut surfaces at the time of cutting. An ink jet recording head characterized by satisfying a relationship of 0.5 ≦ Sj / Qb ≦ 2.5. 2. The sum of the area of the opening of the ink supply hole formed in the one ink reservoir (Sa) and the sum of the area of the opening of the ink collection hole (Sj) are Sa ≦ Sj and the other is The sum (Sb) of the area of the opening of the ink supply hole formed in the ink reservoir and the sum (Sj) of the area of the opening of the ink collection hole satisfy the relationship of Sb ≦ Sj. Claim 1
3. The ink jet recording head according to item 1. 3. The flow path forming the one flow path group is cut by a plane perpendicular to the longitudinal direction of the flow path forming the one flow path group, and the total area (Sa) of the openings of the ink supply holes formed in the one ink reservoir. The sum (Qa) of the areas of the cut surfaces satisfying the relationship of 0.5 ≦ Sa / Qa ≦ 1.0 and the area of the opening of the ink supply hole formed in the one ink reservoir is obtained. The sum (Sa) and the sum (Sj) of the areas of the openings of the ink recovery holes satisfy the relationship of 2.0 ≦ Sj / Sa ≦ 4.6, and the ink supply formed in the other ink reservoir is provided. The sum (Sb) of the area of the opening of the hole and the sum (Qb) of the area of the cut surface when the flow path forming the other flow path group is cut along a plane perpendicular to the longitudinal direction thereof are as follows. While satisfying the relationship of 5 ≦ Sb / Qb ≦ 1.0, the ink formed in the other ink reservoir is The sum of the areas of the openings of the ink supply holes (Sb) and the sum of the areas of the openings of the ink recovery holes (Sj) satisfy the relationship of 2.0 ≦ Sj / Sb ≦ 4.6. 3. The method according to claim 2, wherein
3. The ink jet recording head according to item 1.