JP2000015816A - Ink jet head and method of manufacturing the same - Google Patents

Abstract

(57) [Problem] To provide an economical and practical ink jet head configured to eject ink droplets in a direction perpendicular to a heat generating surface of a heat generating element. A driving circuit and its terminals are formed on a silicon substrate as an initial step of manufacturing an ink jet head, an oxide film and a wiring electrode are formed, a fine resistor (heating element 15) such as Ta-Si-SiO, Ni, etc. (Common electrode 12 and individual wiring electrode 14) are formed to determine the position and shape of the heating element 15. At this time, the heating element 15 is formed in a square shape, and its size is set to a circle 23 ′ having the same diameter as the diameter of the orifice 23.
Set the size to be inscribed in. Further, an allowable error of 2.5 μm, which is a limit of accuracy, that is, a total of 5 μm is set between the partition wall formed on three sides of the heating element 15 and the heating element 15.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet head having a plurality of heating elements which are arranged on a substrate in an array and which are individually separated by partition walls, and a method of manufacturing the same.

[0002]

2. Description of the Related Art In recent years, thermal ink jet printers have been widely used. In the thermal ink jet system, a heating element is heated to generate nuclear bubbles on the heating element in a process of forming ink droplets ejected for printing. These nuclei bubbles coalesce to produce film bubbles. These film bubbles grow by adiabatic expansion. The grown film bubbles shrink due to the heat taken by the surrounding ink.
Eventually, a series of steps in which the film bubbles disappear and wait for the next heating element to be heated are instantaneously performed. The film boiling phenomenon is used in the above steps (1) to (4).

The film boiling phenomenon occurs when an object heated to a high temperature such as quenching of iron is immersed in a liquid and when the surface temperature of the object in contact with the liquid is rapidly increased. The film boiling phenomenon used in a thermal ink jet printer is based on the latter method of "rapidly increasing the surface temperature of an object in contact with a liquid". Further, in such a thermal inkjet head, there is also a configuration in which not only monochrome printing but also full-color printing is performed by discharging inks of three primary colors.

The ink droplets are ejected in a direction perpendicular to the heating surface of the heating element or in a direction parallel to the heating surface of the heating element. In a configuration in which ink droplets are ejected in a direction parallel to the heating surface of the heating element, the ejection energy of the ink droplets is relatively large, and is approximately 8 to 10 μJ per dot.

On the other hand, as a method for manufacturing a full-color thermal ink jet head having a structure in which ink droplets are ejected in a direction perpendicular to the heat generating surface of the heat generating element, a plurality of heat generating elements and individual driving elements are formed using silicon LSI and thin film technology. There is a method of forming a circuit and an ink discharge nozzle (orifice) collectively and monolithically.

According to this method, for example, a resolution of 360
128 for a print head of dpi (dot / inch)
A heating element, a driving circuit, and an orifice (generally a term used for an energy transfer hole or window formed on the end or wall surface of a waveguide or the like). Is 256 if the resolution is 720 dpi
An orifice can be formed with a plurality of heating elements, a driving circuit, and the like.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide an economical and practical ink jet head having a structure for ejecting ink droplets in a direction perpendicular to a heat generating surface of a heat generating element in view of the above-mentioned conventional circumstances. It is to be.

[0008]

The ink jet head according to the first aspect of the present invention comprises a plurality of heating elements arranged in an array on a substrate and arranged separately from each other by partition walls. An ink jet head that supplies ink onto the element and heats the heat generating element to generate bubbles at an interface between the heat generating element and the ink, thereby discharging ink droplets from an orifice provided opposite the heat generating element; Wherein the diameter of the orifice is formed to be approximately 1/2 to 1 / 2.5 of the dot diameter to be finally formed on the paper, and the shape of the heat generating portion of the heat generating element is a circle of the orifice diameter. It is formed and formed in a substantially square shape inscribed in.

[0009] For example, as set forth in claim 2, the distance between the heating element and the partition is set to be 2.0 to 3.0 µm. Further, the partition is configured to be formed so as to overlap with a peripheral portion of the heating element, for example.

Next, a method of manufacturing an ink jet head according to the present invention includes a plurality of heating elements which are arranged in an array on a substrate and which are individually separated by partition walls. Manufacturing an ink jet head that supplies ink to a heating element and heats the heating element to generate bubbles at an interface between the heating element and the ink, thereby discharging ink droplets from an orifice provided opposite the heating element. Forming a diameter of the orifice to be approximately 1/2 to 1 / 2.5 of a dot diameter to be finally formed on a sheet of paper, and changing a shape of a heating portion of the heating element to the orifice. Forming a substantially square inscribed in a circle of diameter.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. 1 (a), (b), (c), FIG. 2 (a),
(b), (c), FIGS. 3 (a), (b), (c) and FIGS. 4 (a), (b), (c)
FIG. 4 is a diagram illustrating a method of manufacturing an inkjet head according to an embodiment in the order of steps. FIGS. 1 (a), (b), and (c) show schematic plan views and cross-sectional views, respectively.
4 (a) and FIG. 4 (a) respectively show a partially enlarged plan view of FIGS. 1 (a), (b) and (c), and FIG. 2 (b) shows the plan view of FIG. 2 (a). A
FIG. 2 (c) is a sectional view taken along arrow A 'of FIG.
3 (b) and 3 (c) are cross-sectional views of the same parts as FIGS. 2 (b) and 2 (c) of FIG. 3 (a), and FIGS. )
FIG. 3A is a cross-sectional view of the same portion as FIGS. 2B and 2C. Also,
The sectional views shown below each of FIGS. 1 (a), (b) and (c) are as follows.
The sectional views are the same as those shown in FIGS. 2 (b), 3 (b) and 4 (b).

In these figures, for the sake of convenience of explanation, one heating head of the full-color ink jet head (the same as the structure of the monochrome ink jet head) is used.
Although only a single heating substrate is shown, a large number of such heating heads (three or four) are formed on a single silicon substrate.

First, as a step 1, a drive circuit and its terminals are formed on a silicon substrate of 4 inches or more by an LSI forming process, and at the same time, an oxide film having a thickness of 1 to 2 μm and a wiring electrode are formed. Next, as a step 2, an electrode made of a fine resistor such as Ta-Si-SiO and Ni is formed by using a thin film technique. In this step, the position and shape of the heating resistor are determined.

FIGS. 1 (a) and 2 (a), (b), (c) show a state immediately after the above-mentioned steps 1 and 2 have been completed.
That is, on the silicon substrate 10, the common electrode 12, the common electrode power supply terminal 13 (see FIG. 1A), the individual wiring electrode 1
4, a resistor (heating resistor) 15, a drive circuit 16, and a drive circuit terminal 17 (see FIG. 1A).

Subsequently, in step 3, a partition member made of an organic material such as photosensitive polyimide is laminated to a height of about 20 μm by coating to form ink grooves corresponding to the individual ink discharge ports, and this is patterned. After doing
Curing (dry curing, baking) by applying heat at 300 ° C. to 400 ° C. for 30 minutes to 60 minutes is performed to form and fix a 10 μm-high partition wall made of the photosensitive polyimide on a silicon substrate. Further, as a step 4, a groove-shaped ink supply path and an ink supply hole are formed in the silicon substrate by wet etching or sand blasting or the like to form an ink passage communicating from the front surface to the back surface of the silicon substrate.

FIGS. 1 (b) and 3 (a), (b), (c) show a state immediately after the above-mentioned steps 3 and 4 are completed.
That is, the groove-shaped ink supply path 18 and the ink supply hole 2
0, the common electrode 12 located on the left side of the ink supply path 18, the portion on which the individual wiring electrode 14 on the right is provided, and a partition wall 19 between each resistor 15.
(19, 19-1, 19-2) are stacked. If the portion 19-1 on the individual wiring electrode 14 is a comb body, the portion of the partition wall 19 laminated between the resistors 15
The portion 19-2 extending between the five has a shape corresponding to the teeth of the comb. As a result, with the teeth of the comb as partition walls, fine ink grooves in which the resistors 15 are located at the roots between the teeth are formed by the number of the resistors 15.

Then, in step 5, on both sides or one side of a polyimide film having a thickness of 10 to 30 μm,
An orifice plate coated with a very thin layer of thermoplastic polyimide, for example, with a thickness of 2 to 5 μm, is attached to the uppermost layer of the laminated structure, and the ink groove formed by the partition wall 19-2 is covered. Fine passage (ink channel)
To form Then, pressure is applied while heating at 200 to 300 ° C. to fix the orifice plate. Then, Ni, C
A metal film such as u or Al having a thickness of about 0.5 to 1 μm is formed.

Further, as a step 6, the metal film on the orifice plate is patterned to form a mask for selectively etching the polyimide.
A plurality of nozzle holes (also called orifices) are formed at once by making holes of 40 μmφ to 20 μmφ in accordance with the above metal film mask by dry etching such as R.
The holes may be formed using an excimer laser or the like.

FIG. 1 (c) and FIGS. 4 (a), (b) and (c) show a state immediately after the above-mentioned steps 5 and 6 are completed.
That is, the orifice plate 21 covers the entire area except for the drive circuit 16 and the power supply terminals 13 and 17, and the ink groove is also covered so that the thickness of the partition / separation member 19 is 10 mm.
A pit-shaped ink groove 22 having a height corresponding to μm is formed. In the orifice plate 21, a nozzle hole (orifice) 23 is formed in a portion corresponding to the resistor 15 by dry etching or excimer laser, thereby completing a heating head 24 having a row of nozzle holes 23. I do.

The processing up to this point is performed in a wafer state.
Finally, as a step 7, cutting is performed by using a dicing saw or the like, the unit is divided into individual units, die-bonded to a mounting board, and terminals are connected to complete.

In the above example, the drive circuit 16 is shown in an exposed state, but a protective film is actually formed. Instead of forming the protective film later, the orifice plate 21 should be extended rightward in FIG. 1 (c) (the same applies to FIGS. 4 (a), (b) and (c)) and laminated. Then, the orifice plate 21 may also be used as a protective film of the drive circuit.

The heating head 24 having the one row of nozzle holes 23 has the structure of a monochrome ink jet head. However, in full-color printing, as described above, the subtractive primary colors of yellow (Y), In addition, black (Bk) dedicated to black portions of characters and images is added to three colors of magenta (M) and cyan (C), and a total of four colors of ink are required. Therefore, at least four nozzle rows are required. According to the above-described manufacturing method, it is possible to form the four rows of heating heads in a monolithic manner, and the positional relationship of each row can be accurately arranged by today's semiconductor manufacturing technology.

FIG. 5 (b) shows the above-mentioned FIGS. 1 (c) and 4 (a),
FIG. 4 is a diagram showing a state in which the heating heads 24 shown in (b) and (c) are arranged in four rows to form a full-color inkjet head. FIG. 5 (a) shows a state in which steps 1 and 2 have been completed in the same manner as shown in FIG. 1 (a) in order to clearly show the configuration in which the heating heads 24 are arranged in four rows. In the example shown in FIG. 5 (b), the orifice plate is used as a protective film for the drive circuit.

As shown in FIGS. 5A and 5B, the ink jet head 25 is formed by arranging four heating heads 24 (24a, 24b, 24c, 24d) on the large substrate 11. Is done. This inkjet head 25
For example, the M ink is supplied from the ink supply path 18a to the ink groove 22 (see FIGS. 1C and 4B) of the heating head 24a, and the heating head 24b is supplied from the ink supply path 18b.
C ink is supplied to the ink groove 22 of the ink supply path 1
8c supplies Y ink to the ink groove 22 of the heating head 24c, and supplies Bk ink to the ink groove 22 of the heating head 24d from the ink supply path 18d.

In the ink jet head 25, at the time of printing, the resistor 15 (see FIGS. 2A and 2B) is selectively energized in accordance with the printing information, instantaneously generates heat and causes a film boiling phenomenon. An ink droplet is ejected from the nozzle hole 23 corresponding to the resistor 15. In such an ink jet method, ink droplets are ejected in a substantially spherical shape having a size corresponding to the diameter of the nozzle hole 23, and are printed on the paper surface with a diameter approximately twice as large.

The thus obtained full-color ink jet head can have 128 nozzles × 4 rows = 640 nozzles when the resolution is 360 dpi, and has a size of approximately 8.5 mm × 19.0 mm. Can be created. If the resolution is 720 dpi, 256 nozzles × 4 rows = 1280 nozzles can be formed in a size of approximately 8.5 mm × 19.0 mm.

In the above-described method of manufacturing the ink jet head 24 or 25, a feature of the present embodiment is that a resistor 15 (hereinafter referred to as a heating element 15) is used.
Is set to a specific size. by this,
In order to use the heat generated by the heat generating element 15 as effectively as possible, that is, to discharge a desired ink droplet with a minimum power consumption. Hereinafter, this will be described.

FIG. 6A is an enlarged view showing the shape of the heating element 15 formed in the step 2 of manufacturing the ink jet head according to the present embodiment, and FIG.
It is a figure which shows the specific size. The figures (a) and (b)
, The same parts as those shown in FIGS. 1 to 4 are given the same reference numerals as in FIGS. 1 to 4 so that FIGS. 1 to 4 can be referred to.

In the manufacturing of the ink-jet head according to the present embodiment, in the above-described step 2, as shown in FIG.
-Form electrodes (common electrode 12, individual wiring electrode 14) made of fine resistance (heating element 15) such as SiO and Ni or the like.

Then, the shape of the heating element 15 is formed in a square as shown in FIG. In this example, the size of the square is set to a size inscribed in a circle 23 'having the same diameter as the diameter of the orifice 23 formed corresponding to the heating element 15, as shown in FIG. 6B. You. In the design of the ink jet head according to the present embodiment, the diameter of the orifice 23 as a reference of the heating element 15 is determined almost automatically when the size of a dot (pixel) to be formed on a sheet is set. .

That is, the size (area) of the dot formed on the paper by the ink droplet ejected from the orifice 23 is twice to 2.5 times the diameter of the orifice 23 from which the ink droplet is ejected. Is known empirically. This is a size formed when ink ejected as substantially spherical liquid droplets having a diameter similar to the diameter of the orifice 23 collides with the paper surface and spreads flat.

Therefore, if the size of a dot to be formed on the paper surface is set in advance, the size of the orifice 23 is calculated backward from this, and the size of the orifice 23 is set to one of the size of the dot.
/ 2 to 1 / 2.5. Next, based on the determined size of the orifice 23, the size of the heating element 15 is set to a size inscribed in the circle 23 'of the diameter of the orifice 23 as described above.

As described above, when the size of the heating element 15 is set to a size inscribed in the circle formed by the orifice 23, all of the ink droplets due to the nuclear bubbles generated on the heating element 15 are completely exhausted. And is discharged toward the outside (to the paper surface), the power consumption is effectively consumed, and the power is not wasted.

As described above, even if the relationship between the size of the heating element 15 and the size of the orifice 23 is properly determined, the partition wall 19-2 (see FIG. 3) that separates the adjacent heating elements 15 from each other.
(See (a), (b) and (c)) and the bottom of the comb-shaped partition (partition 19).
If the gap between the heating element 15 and the orifice 23 is not appropriate, the relationship between the size of the heating element 15 and the size of the orifice 23 will not function effectively. In this embodiment, the positional relationship between the heating element 15 and the partition walls 19-1 and 19-2 is strictly set so that this functions effectively. Hereinafter, this will be described.

FIG. 7A is an enlarged view schematically showing the positional relationship between the heating element 15 and the partition walls 19 (19-1, 19-2) in the present embodiment, and FIG. CC ′ of (a)
FIG. 3C is a sectional view taken along the line DD ′ in FIG. 1A, 1B, and 1C, the same parts as those shown in FIGS. 1 to 4 and 6 are shown in FIGS.
The same reference numerals are used to denote them.

The shape of the heating element 15 shown in FIGS. 7A, 7B and 7C is rectangular as shown in FIGS. 6A and 6B. For the length H of the partition wall 19-2
Is 5 μm longer than the length H of one side of the heating element 15.
Only set to larger dimensions. This is 2.5 μm between the heating element 15 and the partition walls 19-1 and 19-2.
Is set.

The margin of the gap G is close to the limit of the accuracy of mask alignment and the accuracy of pattern processing when the heating element 15 having a length H of one side is to be arranged in the partition wall 19-2 at the interval P. Value. As long as the current thin film processing technology is used, if there is a margin (tolerance) of 2.5 μm on each side, that is, a total of 5 μm, the heating element 15 can be surely arranged in the partition wall 19-2.

In the present thin film processing technology, the heating element 15 can be arranged as designed by setting a margin (permissible error) of 2.5 μm on each side as described above. Each of the tolerances may be stricter, such as 2.0 μm, or slightly less, such as 3.0 μm. In any case, it is preferable to set the range of 2.0 μm to 3.0 μm.

FIG. 8 shows the size (diameter, μm) of a dot printed on a sheet set based on the above-described design concept.
φ), the minimum diameter and the maximum diameter (μmφ) of the orifice 23 determined correspondingly, the dimension (μm) of one side of the resistor (heating element) 15 set correspondingly, and It is a table | surface which shows the example of the relationship of the space | interval (micrometer) of the partition 19-2 set correspondingly.

FIG. 4 illustrates four examples of the above relationships from row 31 to row 34. For example, taking the example shown in row 32 as an example, this is a design example in which a dot diameter of 60 μmφ is required as a print dot, and an attempt is made to form an orifice having a larger half diameter. In this case, the diameter of the orifice is set to 30 μmφ, and when an orifice having a smaller diameter of 1 / 2.5 is to be formed, the diameter of the orifice is set to 24 μmφ.

Also, based on the size of these orifices, in each case, the size of the heating element inscribed in a circle having the same diameter as the diameter of the orifice is about 21 μm on a side for the larger one and for the smaller one. Indicates that one side is set to approximately 17 μm. And the interval between the partition walls,
This indicates that the size is set to 26 μm when the heating element is large, and to 22 μm when the heating element is small.

As described above, in the present embodiment, the size of the heating element is set to a size inscribed in the circle having the size of the orifice, and the interval between the partition walls is set to be 5 times smaller than the size of the heating element.
μm is set larger. Thus, a desired print output can be obtained with the minimum power consumption. For example, in the design configuration of the periphery of the heating element corresponding to the size of the print dot of 60 μm φ shown in the example of the above-mentioned row 32, it was obtained as an experimental result that the energy of foaming per dot may be 0.5 μJ or less. ing.

As described above, the interval between the partition walls is an important factor for efficiently ejecting ink droplets at the bubbling pressure formed on the heating element. , That is, without giving a margin of 5 μm, the relationship between the heating element and the partition wall can be set. Hereinafter, this will be described.

FIG. 9A is an enlarged view schematically showing the positional relationship between the heating element 15 and the partition walls 19 (19-1, 19-2) according to another embodiment, and FIG. E- of FIG.
FIG. 7C is a sectional view taken along the line E ′, and FIG. 7C is a sectional view taken along the line FF ′ in FIG. 6A, 6B and 6C, the same parts as those shown in FIGS. 1 to 4 and 6 have the same reference numerals as those in FIGS. It is shown with the addition.

The shape of the heating element 15 shown in FIGS. 9A, 9B and 9C is also rectangular as shown in FIGS. 6A and 6B. However, in this case, the lengths H1 and H2 of one side of the heating element 15 are set.
In contrast to (H1 = H2), the intervals P1 and P2 (P1 = P2) between the partition walls 19-2 are equal to the length H1 of one side of the heating element 15.
The dimension is set to be smaller than that by 5 μm, and the depth is set to be smaller by 2.5 μm. That is, the partition 19
-1 and 19-2 are formed so as to overlap the periphery of the heating element 15.

Also in this case, since there is a margin (tolerance) of 5 μm in total, the above-mentioned overlapping can be sufficiently contained within the tolerance. That is, for example, in the case of the heating element 15 and the partition wall 19-2 shown in the lower part of FIG. 9 (a), the center lines K coincide with each other, and there is no error in the positional relationship, and therefore, the overlap margins G2-1 and G2- 2
Have the same width and are most appropriately in a positional relationship. And
In the case of the heating element 15 shown in the upper part of FIG. 9A, both centers are shifted, and the overlapping margin G1-1 on the upper side of the drawing is wide, and the overlapping margin G1-2 on the lower side is narrowed accordingly. I have. However, there is no problem with the allowance of 5 μm in total for the partition wall 19-1.
, 19-2 and the periphery of the heating element 15 are formed.

Then, in the above-described peripheral configuration of the heating element,
The lengths of the intervals P1 and P2 between the partition walls 19-2 are as shown in FIG.
The size of the heating element 15 is set so as to be inscribed in a circle having the same diameter as the diameter of the orifice.
In this case, ink droplets can be formed to fill the inside of the partition wall more fully than in the cases of FIGS.

[0048]

As described in detail above, according to the present invention, the shape of the heating element (resistor) is formed to a size inscribed in a circle having the same diameter as the diameter of the nozzle (orifice).
The ink droplets due to the bubbling energy can be ejected as ink droplets of the full diameter of the orifice without leaving any excess, so that efficient printing can be performed with minimum power consumption and economical.

Further, since the space between the partition walls is formed close to or overlapped with the periphery of the heating element, ink droplets due to foaming energy can be concentrated to the maximum toward the orifice. It is economical because efficient printing can be performed with electric power.

[Brief description of the drawings]

FIGS. 1A, 1B, and 1C are a schematic plan view and a cross-sectional view illustrating a method of manufacturing an inkjet head according to an embodiment in the order of steps.

2 (a) is a partially enlarged view of the plan view of FIG. 1 (a), FIG. 2 (b) is a sectional view taken along the line AA 'of FIG. 1 (a), and FIG. )
13 is a sectional view taken along the line BB ′ of FIG.

FIG. 3 (a) is a partially enlarged plan view of FIG. 1 (b), and FIGS. 3 (b) and 3 (c) are the same as FIGS. 2 (b) and 2 (c) of FIG. It is sectional drawing of a part.

FIG. 4 (a) is a partially enlarged plan view of FIG. 1 (c), and FIGS. 4 (b) and 4 (c) are the same as FIGS. 2 (b) and 2 (c) of FIG. It is sectional drawing of a part.

5A and 5B are diagrams showing a state in which the heating heads of FIG. 1C are arranged in four rows to form a full-color thermal ink jet head, and FIG. 5A is a diagram showing a state in which Step 1 and Step 2 have been completed; ) Is the completed drawing.

FIG. 6A is an enlarged view showing the shape of a heating element (resistor) formed in step 2 of the inkjet head of the present embodiment, and FIG. 6B is a view showing a specific size thereof.

7A is an enlarged view schematically showing the positional relationship between the heating element of this example and the partition, FIG. 7B is a cross-sectional view taken along the line CC ′ of FIG.
(c) is a sectional view taken along the line DD ′ of (a).

FIG. 8 shows the relationship between the dimension of a resistor (heating element) and the distance between partition walls determined based on the design concept of the present invention in accordance with the minimum diameter and the maximum diameter of an orifice corresponding to the size of a print dot. It is a chart showing an example.

FIG. 9A is an enlarged view schematically showing a positional relationship between a heating element and a partition wall in another embodiment, and FIG. 9B is an enlarged view of E-line in FIG.
FIG. 7C is a sectional view taken along the line E ′, and FIG. 7C is a sectional view taken along the line FF ′ of FIG.

[Explanation of symbols]

 10, 11 Silicon substrate 12 Common electrode 13 Common electrode power supply terminal 14 Individual wiring electrode 15 Resistance (heating element) 16 Drive circuit 17 Drive circuit terminal 18 Ink feed path 18-1 Groove 18-2 Groove wall 18 'Hole 19 Partition wall 19 -1 Comb Equivalent Portion 19-2 Comb Equivalent Portion 20 Ink Supply Hole 21 Orifice Plate 22 Ink Groove 23 Nozzle Hole (Orifice) 23 'Circle of Orifice Diameter 24 (24a, 24b, 24c, 24d) Heating Head 25 Full-color inkjet head

Continued on the front page F-term (reference) 2C057 AF54 AF91 AF93 AG01 AG07 AG12 AG46 AG92 AG93 AP02 AP13 AP23 AP32 AP33 AQ02 BA04 BA13

Claims (4)

[Claims] A plurality of heating elements arranged in an array on a substrate and individually spaced apart from each other by partition walls; ink is supplied onto the heating elements to heat the heating elements; An ink jet head that discharges ink droplets from an orifice provided opposite to the heating element by generating bubbles at an interface between the element and the ink, the diameter of the orifice being finally formed on paper. An ink jet head having a diameter of about 1/2 to 1 / 2.5 of a dot diameter, and wherein a shape of a heat generating portion of the heat generating element is formed in a substantially square shape inscribed in a circle having the orifice diameter. . 2. An interval between the heating element and the partition wall is 2.
2. The ink jet head according to claim 1, wherein the ink jet head is set to have a thickness of 0 to 3.0 [mu] m. 3. The ink jet head according to claim 1, wherein the partition wall is formed so as to overlap a peripheral portion of the heating element. 4. A plurality of heating elements arranged in an array on a substrate and individually separated by partition walls, and ink is supplied onto the heating elements to heat the heating elements. A method of manufacturing an ink jet head for ejecting ink droplets from an orifice provided opposite to a heating element by generating bubbles at an interface between an element and the ink, wherein the diameter of the orifice is finally adjusted on paper. Forming a diameter of about 1/2 to 1 / 2.5 of the diameter of the dot to be formed, and forming the shape of the heat generating portion of the heat generating element into a substantially square shape inscribed in the circle of the orifice diameter. A method of manufacturing an ink jet head.