JP2002331665A - Thermal ink jet head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermal ink jet head in which films can be formed at a high speed and a short circuit between discrete electrodes is prevented even when defects such as pinholes occurs in an insulating layer. SOLUTION: A radiation layer 26 is formed on a narrow face of about a half of a glass substrate 25, then the insulating layer 28 is spread on the whole face of the substrate. A heating resistor 29a is disposed above a right end of the radiation layer 26. A common electrode 31b formed to the whole face above the radiation layer 26 is connected to a left end of the heating resistor 29a. The discrete electrode 31a formed onto the insulating layer 28 of a part where the radiation layer 26 is not formed is connected to a right end of the heating resistor 29a. An ink supply groove 33, an ink supply hole 34 and a diaphragm 32 are formed, an orifice plate 35 is layered, and an orifice 36 is bored. The glass substrate 25 cut as a chip is die bonded by a die bonding agent 39 to a radiation plate 37. Then, the radiation layer 26 exposed to the left end and the radiation plate 37 are thermally coupled by a heat transfer paste 41. Since the radiation layer 26 is absent immediately below the discrete electrode 31a, no short circuit takes place even if the insulating layer has the pinhole.

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 structure excellent in heat dissipation and insulation.

[0002]

2. Description of the Related Art Conventionally, there is a printer which performs printing by discharging ink from an ink jet head onto a paper surface. In a printing method using this printer, ink droplets (print dots) are ejected from fine holes (ejection nozzles) arranged in large numbers on the ink ejection surface of an ink jet head, and the ink droplets (print dots) are printed on a print medium such as paper or cloth. Let it land and absorb it,
Thus, printing of characters, images, and the like is performed, the generation of noise is small, no special fixing process is required, and full-color recording is a relatively easy recording method.

As a method of discharging ink droplets, a heating element is arranged in a fine ink pressurizing chamber, and an electric pulse is applied to the heating element to generate heat, thereby generating film bubbles at an interface between the ink and the heating element at high speed. There is a thermal ink jet head that discharges ink droplets from discharge nozzles by using the instantaneous expansion force of the film bubbles.

[0004] The above-mentioned thermal type ink jet head has two configurations depending on the direction of ink droplet ejection. One is a configuration in which ink droplets are ejected in a direction parallel to the surface of the heating element. The other is configured to discharge ink droplets in a direction perpendicular to the surface of the heating element. Above all, those that eject ink droplets in the direction perpendicular to the surface of the heating element are called roof shooter type or top shooter type inkjet heads, and eject ink droplets in a direction parallel to the surface of the heating element. Compared to the configuration,
It is known that power consumption is extremely small.

[0005] As a method of manufacturing this roof shooter type ink jet head, for example, a large number of pieces of about 10 mm x 15 mm divided into, for example, 90 pieces or more on one silicon wafer having a diameter of 6 x 25.4 mm or more. A large number of heating elements, a driving circuit for individually driving these elements, an ink flow path for supplying ink thereto, and ejection of ink droplets on the chip substrate by utilizing LSI forming technology and thin film forming technology. And the discharge nozzles to be formed are collectively formed monolithically.

An ink jet head individually formed on a chip substrate having a size of about 10 mm × 15 mm as described above is mainly used for a serial printer in which the ink jet head reciprocates in the width direction of a sheet to perform printing. Although used as an inkjet head, in recent years, large and long inkjet heads have been created for line printers, which have a discharge nozzle array that is as wide as the paper and are fixed to the printer body, and only the paper moves to perform printing. There has been proposed a method of using a glass substrate instead of a silicon wafer having a limited size as a substrate for performing the above.

FIGS. 8 (a), (b), (c), FIGS. 9 (a), (b), (c) and FIG. 10 show a basic manufacturing method of such a conventional thermal ink jet head. FIG.
9 (a), 9 (b) and 9 (c) and FIGS. 9 (a), 9 (b) and 9 (c) each show an upper plan view schematically showing a state of being formed on a substrate in a series of steps. 3 is a sectional view taken along the line AA ′ of FIG.

FIGS. 8 (a), (b), (c) and FIGS. 9 (a), (b),
In (c), for the sake of simplicity of illustration, a large number of heating resistors or orifices (ink discharge nozzles) are formed at the end of the head, such as thousands of thermal ink jet heads for line printers. Only six are shown as representatives. These figures show a monochrome thermal inkjet head having only one row of orifices for convenience of explanation.

First, as shown in FIG. 8A, a heat radiation layer 2 made of a metal film such as Cu or Al and having a thickness of about 5 μm is formed on the upper surface of a glass substrate 1 as shown in FIG.
An insulating layer 3 made of an oxide film having a thickness of, for example, 1 to 2 μm, such as a Si—O ₂ or Ta—Si—O, is formed thereon.

Next, in step 2, a heat-generating resistive film made of Ta-Si-ON or the like and having a thickness of, for example, about 5000 ° is formed on the entire surface of the insulating layer 3 by using a thin film forming technique.
After forming a metal film having a thickness of, for example, 8000 ° to form a two-layered structure of Au and W—Ti or a single-layered structure of Al or the like, a photolithography technique is used.
The pattern of the wiring and the thermal resistor is formed.

As a result, as shown in FIG. 8B, one end of the heating resistor 4a of the heating resistor film 4 patterned into a stripe shape (the right end in FIG. 8B). ), An individual electrode 5 formed on each of the strips is connected, and at the other end of the heating resistor 4a, a common electrode 6 formed continuously on all the strips is formed. It is connected.
In this step, the arrangement of the heating resistors 4a and the arrangement pitch thereof are determined. In the center of the common electrode 6, an opening 7 extends in parallel to the arrangement direction of the heating resistors 4 a.
Is formed, and the surface of the insulating layer 3 is exposed in the opening 7.

Subsequently, in step 3, a film having a thickness of about 20 μm is formed from an organic material such as photosensitive polyimide, and is patterned by photolithography.
By firing at 300 to 400 ° C. for 1 to 2 hours, the heating resistor 4a is heated at a predetermined position, that is, as shown in FIG.
And the entire heating resistor 4 excluding the common electrode 6
A partition 8 having a thickness (height) of 10 μm is formed so as to extend between “a” and surround each heating resistor 4a from three sides.

Further, as a step 4, the insulating layer 3 which is first exposed in the opening 7 of the common electrode 6 by wet etching or sand blast processing, that is, the upper surface of the glass substrate 1, as shown in FIG. About 1/3 of the ink supply groove 9 is formed, and an ink supply hole 11 communicating with the bottom of the ink supply groove 9 and penetrating the back surface of the glass substrate 1 is formed.

Next, as a step 5, as shown in FIG. 9B, an orifice formed by coating an adhesive such as a thermoplastic polyimide of 2 to 5 μm on both sides or one side of a polyimide film having a thickness of 10 to 30 μm. The orifice plate 12 is mounted on the partition wall 8 and heated and heated to 200 to 300 ° C. in vacuum to apply the pressure. An ink flow path 13 communicating with the body 4a is formed.

Further, in step 6, on the orifice plate 12, Al or Ti made of, for example, 0.5 to 0.5 mm thick is formed.
A 1 μm metal film 14 is formed by, for example, vacuum evaporation, and an orifice pattern 15 having a diameter of 20 to 40 μm is formed in the metal film 14 by photolithography to form a metal mask.

Subsequently, as a step 7, a helicon wave or an ECR is formed according to the orifice pattern 15 of the metal mask.
The orifice plate 12 is etched by a dry etching device such as the one shown in FIG.
6 are collectively formed. Thus, a plurality of thermal inkjet heads 17 are completed on the glass substrate 1.

Thereafter, as a step 8, cutting is performed by using a dicing saw or the like to divide and cut into individual head chips, and as shown in FIG. 10, a TCP 19 on which a driver IC 18 is mounted is connected to the individual electrodes 5 by terminals. The opening of the ink supply hole 11 is aligned with the ink supply port 22 of the heat sink 21, and the glass substrate 1 is
Is die-bonded to the heat sink 21 to complete a thermal ink jet head module 24 in practical units.

The thermal ink jet head module 24 is mounted on a printer and supplied with ink from an external ink tank via an ink supply port 22 of a heat radiating plate 21, and the ink is supplied to the ink supply hole 11, the ink supply groove 9, and the like. The ink flows through the ink flow path 13 and is supplied to the resistance heating element 4a. The resistance heating element 4a is selectively applied with a drive voltage in accordance with the print data by the individual electrode 5 and instantaneously generates heat. A film bubble is generated, and ink droplets are ejected from the orifice 16 by the expansion force of the film bubble to print (print) characters and images on a paper surface (not shown).

Conventionally, when glass is used for the substrate as described above, if the portion of the ink jet head 17 excluding the drive circuit is formed directly on the glass substrate 1, the glass has poor heat radiation characteristics as compared with silicon. As described in 10, while the ink is continuously ejected from the orifice 16, the heat generated by the heating resistor 4 a is accumulated in the glass substrate 1, and a phenomenon that the proper ink cannot be ejected may occur. It is known. The structure shown in FIG. 8A in which the heat radiation layer 2 is formed on the glass substrate 1 and the insulating layer 3 is formed thereon has been proposed in order to solve the above problem.

[0020]

Incidentally, since the heat radiation layer 2 is a metal film, it certainly has high thermal conductivity but is also a conductive material. Therefore, if the insulating layer 3 deposited on the heat radiation layer 2 has a defect such as a pinhole, the individual electrode 5 and the heating resistor 4a are formed of a metal film through the pinhole. And the individual electrodes 5 or the heating resistors 4a are short-circuited via the heat radiation layer 2. When such a short circuit occurs, the heat generating function of the resistance heating element 4a is impaired, and the entire ink jet head becomes defective. Therefore, the insulating layer 3 must be a highly reliable insulating layer free from defects such as pinholes.

However, in order to form a high-quality insulating layer free from defects such as pinholes, it is necessary to form a dense film at a low film forming rate by a dry process. However, this would result in a low-productivity film formation process, which is not suitable for mass production in factories. Further, if such a low-productivity film forming process is performed using an expensive film forming apparatus, an increase in manufacturing cost cannot be avoided. Further, when the number of orifices increases as in a head for a line printer, the number of wirings of the individual electrodes increases, so that the occurrence rate of short circuits increases and the production yield decreases. This is the same regardless of the film formation method, and it is extremely difficult to form the insulating layer as a high-quality film without pinholes at a high speed.

FIGS. 11A and 11B show Japanese Patent Application No. 2000-374 filed by the present applicant to solve the above problem.
FIG. 9 is a diagram showing a configuration of a main part proposed in the '854 application. Note that FIG. 11A corresponds to an enlarged view obtained by rotating the upper plan view of FIG. 8B by 90 degrees in a counterclockwise direction, and FIG. 13 is a sectional view taken along the line BB ′ of FIG. 8 (a) and 8 (b) are the same as those in FIGS. 8 (a) and 8 (b).
The same numbers as in (b) are given.

As shown in FIGS. 11A and 11B, the heat radiation layer 2 '
Are formed in a strip shape along the shape of the individual electrode 5. Thus, even if the insulating layer 3 formed thereon has a defect such as a pinhole, the heat radiation layer 2 ′ itself is divided into strips along the shape of the individual electrode 5, and thus the heat radiation layer 2 ′ is formed. This prevents the occurrence of a short circuit between the individual electrodes 5 via.

An object of the present invention is to provide a further improvement,
A thermal ink jet that can form a film at a high speed and realizes a configuration in which a short circuit does not occur between individual electrodes even when a defect such as a pinhole is present in an insulating layer by a method different from that of Japanese Patent Application No. 2000-374854. Is to provide a head.

[0025]

The construction of the thermal ink jet head according to the present invention will be described below. The thermal ink jet head of the present invention is formed by sequentially laminating an orifice plate provided with a heat radiation layer, an insulating layer, a heating resistor, a signal electrode and a common electrode layer, a partition, and an orifice on one surface of the substrate. A heat radiator is arranged on the one side and the opposite side, and a voltage is applied between the signal electrode and the common electrode to cause the heat generating resistor to generate heat, thereby causing film boiling at an interface between the heat generating resistor and the ink. In the thermal ink jet head which discharges the ink from the orifice to the outside, the heat dissipation layer is provided at a position except for a lower layer portion of the signal electrode, and a heat transfer member thermally couples the heat dissipation layer and the heat dissipation body. It is comprised so that it may have.

The heat radiation layer thermally coupled to the heat radiator via the heat conductor is provided in a groove formed on the one surface of the substrate. You. Further, the heat conductor is provided, for example, at an end of the substrate as described in claim 3, and is provided so as to penetrate the substrate, as described in claim 4, for example. In this case, the heat transfer body is configured to be adhered to a wall surface of a through hole formed in the substrate, for example, as described in claim 5, and the heat transfer body is formed on the substrate, as described in claim 6, for example. It is configured to fill the formed through hole.

[0027]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1A is a plan view showing a state of forming a heat radiation layer during a manufacturing process of the thermal ink jet head according to the first embodiment, and FIG. 1B is a sectional view taken along a line CC ′ in FIG. FIG. 4C is an enlarged view of the portion shown in FIG. 5B after the thermal ink jet head is completed.

In this embodiment, the steps of manufacturing the thermal ink jet head include forming a heat radiating layer composed of a metal film on a glass substrate and an insulating layer thereon, and forming a heating resistor and an individual electrode on the insulating layer in the step. And formation and patterning of common electrodes, formation of partition walls in the process, formation of ink supply grooves and ink supply holes in the process, lamination of orifice plates in the process, formation of orifice pattern metal masks on the orifice plate in the process, processes There are eight steps to the formation of an orifice by dry etching, the completion of a practical unit of a thermal ink jet head module by cutting and die bonding, and these steps are the same as the conventional steps 1 to 1 described with reference to FIGS. This is almost the same as the eight steps up to the step 8, except that the method of forming the heat radiation layer is different.

In this example, the heat radiation layer is formed in the process by, for example, Cu (copper), Al (aluminum),
First, a metal such as Ti (titanium) is used.
Is formed by sputtering, vacuum deposition,
Alternatively, it is formed by plating or the like.

Next, by photolithography technology,
As shown in FIGS. 1A and 1B, the heat radiation layer 26 is patterned not on the entire upper surface of the glass substrate 25 but on a substantially half surface (the left half surface in the example shown in FIGS. 1A and 1B). . In the heat radiation layer 26 patterned on this half surface, a cutout hole 27 is formed near the center of the substrate and extends elongated in parallel with the longitudinal direction of the substrate. An insulating layer 28 is deposited on the entire surface on this, and FIG.
As shown in FIG. 7, a cutout pattern is formed in a portion corresponding to the cutout hole 27 and a portion corresponding to the left end of the glass substrate 25. The surface of the glass substrate 25 is exposed in the notch pattern corresponding to the notch hole 27, and the heat radiation layer 26 is exposed in the notch pattern corresponding to the left end of the glass substrate 25.

After that, the insulating layer 2 is formed by a process.
8, a heating resistor film 29 and an electrode film 31 are formed, and the heating resistor 29a, the individual electrodes 31a and the common electrode 31b are patterned. In the process, a resin layer is formed, patterning is performed by photolithography and etching, and firing is performed. The partition wall 32 is formed by the process, and an ink supply groove 33 and an ink supply hole 34 communicating with the groove are formed in the process.

At this time, the heating resistor 29a extends along the outer end of the elongated portion formed closer to the center of the substrate than the cutout hole 27 of the heat radiation layer 26, as shown in FIG. The ink supply groove 33 is formed in the cutout hole 27 of the heat radiation layer 26 so as to open inside the edge thereof.

The positional relationship between the heat radiating layer 26 and the heating resistor 29a is different from a different viewpoint.
At the right end of 9a, a step is formed on the substrate surface in a shape cut off to the right. Thereby, the insulating layer 28,
The individual electrode 31a and the heating resistor film 29 below the individual electrode 31a sequentially form steps on the right side of the heating resistor 29a. In other words, the heat radiation layer 26 does not exist in the lower layer of the individual electrode 31a.

After that, an orifice plate 35 is laminated by a process, and an orifice 36 is formed by a process and a process.
The ink supply hole 34 is aligned with the ink supply port 38 of the heat radiating plate 37 serving as a heat radiator by die bonding with a die bonding agent 39 to complete the ink jet head module 40. At this time, although not specifically shown, the terminal on which the TCP on which the driver IC is mounted and the individual electrode 31a are connected as in the case of FIG.

At this time, as shown in FIG.
A dispenser (for connecting electronic components mounted and mounted on a circuit board in a board unit manufacturing line or the like) to circuit terminals from the heat dissipation layer 26 exposed at the left end of the glass substrate 25 to the left end of the heat sink 37. (A device for applying a solder base on a circuit board) to apply a heat transfer paste 41 as a heat transfer body made of, for example, an Ag paste or the like, and by curing the paste, the heat transfer layer 41 and the heat radiating plate 37 are transferred. Thermal bonding is performed via the thermal paste 41.

Thus, as shown in FIG. 1C, only the common electrode 31b and the lower part of the heating resistor 29a are disposed.
That is, as shown in FIGS. 1 (a) and 1 (b), the heat stored by the heat generated by the heat generating resistor 29a on the heat radiation layer 26 attached to the half surface of the glass substrate 25, which is smaller than usual, 26 and the heat radiating plate 37 are thermally coupled by the heat transfer paste 41 and have a structure in which heat is actively released to the outside, so that heat is appropriately dissipated without unnecessary heat storage in the heat radiating layer 26, Appropriate printing performance can be maintained.

Here, the reason why the heat radiation layer 26 is disposed only below the common electrode 31b and the heating resistor 29a as shown in FIG. 1C, that is, from the lower layer of the individual electrode 31a to the heat radiation layer 26 The reason why the configuration is made by removing the above will be described. Fig. 2 (a),
FIG. 3B is a view for explaining the reason why the heat radiation layer 26 is removed from the lower layer of the individual electrode 31 a, and FIG.
FIG. 3 is a diagram showing a wiping member that is also mounted together with the inkjet head module 40 when the inkjet head module 40 is mounted on the printer main body, and FIG. FIG. In FIG. 1B, the same components as those in FIGS. 1A, 1B, and 1C are assigned the same numbers as those in FIGS. 1A, 1B, and 1C. Is shown. The heat radiation layer is not shown.

In the thermal ink jet head shown in FIG. 3A, the arrangement pitch of the orifices 36 is 42.3.
μm and the size of the heating resistor 29a is 25 × 25 μm
^When it is ² , it is assumed that the structure has good foaming characteristics of the ink. 1.5 mm from one end of the heating resistor 29a to the end of the orifice plate 35 (the right end in FIG. 2 (b)), and 1 mm that is further exposed to the outside.
, And an individual electrode 31a having a total length of 2.5 mm is extended.

1 m exposed to the outside of the individual electrode 31a
The portion m is a joining portion for joining with FPC or TCP, and a length of at least 1 mm is necessary in order to make this joining surely. The 1.5 mm length of the individual electrode 31a of the portion extending from one end of the heating resistor 29a, which is the lower layer of the orifice plate 35, to the end of the orifice plate 35 is such that the orifice plate 35 has at least this much. The length is determined automatically because the width is required.

That is, the blade 4 of the wiping member 42 for cleaning the nozzle after the ink is discharged from the orifice 36.
3 requires a width of at least 2 mm as a dimension for reliably cleaning the nozzle. That is, the orifice 36
1 mm is required as the length from the center to the end which faces the.

As the orifice plate 35 for this,
The length from the end of the heating resistor 29a to the end of the orifice plate 35 needs to be 1.5 mm, which is the above 1 mm plus the clearance 0.5. After all this length 1.
5 mm plus the length of the exposed part 1 mm, for a total of 2.5 m
It is necessary to arrange the individual electrodes 31a having a length of m.

Here, the width of the individual electrode 31a is 35 μm,
If the length is 2.5 mm as described above, the individual electrodes 31
The area of a is 87500 μm ² . On the other hand, since the heating resistor 29a has a width and a length of 25 μm, its area is 625 μm ² . Therefore, the heating resistor 2
9a and the individual electrode 31a have an area ratio of “625: 8750”.
0 ", that is," 1 to 140 ". In other words, the electrical holes generated between the individual electrode 31a (although the heating resistance film 29 is actually interposed) and the heat radiation layer (not shown) are generated due to the pinholes generated in the insulating film 28 which cannot be avoided due to technology. The occurrence rate of a short circuit in the portion of the individual electrode 31a is 140 times that in the portion of the heating resistor 29a.

In the present invention, the heat radiation layer 26 is disposed only below the common electrode 31b and the heating resistor 29a as shown in FIG. 1C, and the heat radiation layer 26 is removed from the lower layer of the individual electrode 31a. It is based on the above-mentioned short circuit occurrence rate. In other words, by adopting a structure in which the heat radiation layer is not formed in the lower layer of the individual electrode 31a, the occurrence rate of short-circuit is reduced to 1/1 of the conventional structure.
It is set to be 40 or less.

FIG. 3A is a plan view showing the state of formation of a heat radiation layer during the manufacturing process of the thermal ink jet head according to the second embodiment, and FIG. 3B is a plan view of FIG. −
FIG. 3C is an enlarged view of the portion shown in FIG. 3B after completion of the thermal ink jet head. still,
The configurations shown in FIGS. 1 (a), 1 (b) and 1 (c) are the same as those shown in FIG.
Since the configuration is the same as that shown in (a), (b), and (c), the same components as those in FIGS. 1 (a), (b), and (c) are assigned (Actually, the insulating layer, the heating resistance film, and the electrode film are also deformed due to the difference in the configuration of the heat radiation layer, but these are the same as the case of FIG. 1 in the process.
Here, the same numbers are given assuming that they are the same also in the configuration).

As shown in FIGS. 3 (a), 3 (b) and 3 (c), in this thermal ink jet head, the heat radiation layer 44 is formed by exposing the surface thereof to the same plane as the upper surface of the glass substrate 25. That is, in the process of this example, first, the glass substrate 25
Heat radiation layer 4 to be formed later as shown in FIGS. 3 (a) and 3 (b)
A groove 45 having the same shape as that of the groove 4 is formed, and a heat radiation layer 44 is formed in the groove 45. Since the groove 45 is relatively wide, it can be easily formed by sandblasting.

In this embodiment, since the heat radiation layer 44 is formed on the same surface as the glass substrate 25, the insulating layer 28, the heating resistor film 29, and the individual electrodes 31a are formed as shown in FIG.
Are formed in a planar shape, and no step is formed anywhere. Therefore, problems such as non-uniformity of film formation often occurring at a step portion and disconnection of the individual electrode 31a due to the non-uniformity are caused. Can be eliminated.

FIGS. 4A to 4E are views showing a modification of the second embodiment. FIG. 4A shows a state in which a heat radiation layer is formed during a manufacturing process of the thermal ink jet head. FIG. 2B is a cross-sectional view taken along the line EE ′ of FIG.
FIG. 1C is a sectional view taken along the line FF ′ of FIG. 1B, and FIG. 1D is an enlarged view of the portion shown in FIG. 1B after the thermal ink jet head is completed. FIG. 4 is an enlarged view of a portion shown in FIG. The thermal ink jet heads shown in FIGS.
Except for the heat radiation layer and the ink supply groove, the structure is the same as that of the thermal ink jet head shown in FIGS. 3A, 3B, and 3C. 3
The same numbers as in (a), (b), and (c) are given (however, only the parts necessary for the description are omitted, and others are omitted).

As shown in FIGS. 4A to 4E, the ink supply groove 46 is formed not as a single groove but as a plurality of grooves. Accordingly, in the case of FIGS. 1 and 3, the heat radiation layer 47 is divided into left and right portions with the ink supply groove 33 interposed therebetween, but in this example, as shown in FIGS. 4 (a), (c), and (e). As shown, right and left connecting portions 47a are formed between the ink supply grooves 46. Thereby, the heating resistor 29a of the heat radiation layer 47 is formed.
From the heat transfer paste 41 (see FIG. 1 (c))
Since the heat transfer path to “b” is increased by the amount of the connecting portion 47a, it becomes easier to further dissipate the heat to the outside.

In the first and second embodiments, the heat radiation layer 26 (4) formed on the upper surface of the glass
4 or 47) and the heat-dissipating plate 37 to be die-bonded are described by using an example in which the heat transfer paste 41 is used to thermally couple the heat-dissipating plate 26. The heat radiation layer is not limited to the plate 37, and another heat radiation layer may be formed on the lower surface of the glass substrate 25 and thermally coupled to the lower heat radiation layer. This example will be described below as third and fourth embodiments.

FIG. 5A is a plan view showing the state of formation of the upper heat radiation layer during the manufacturing process of the thermal ink jet head according to the third embodiment, and FIG. 5B is a plan view of FIG. FIG. 5 is a sectional view taken along the line GG ′, and also shows a lower heat dissipation layer. FIG. 1C is an enlarged view of the portion shown in FIG. 1B after the thermal ink jet head is completed.

The structure shown in FIGS. 5A, 5B and 5C is the same as that shown in FIG. 3 except for the lower heat radiation layer, the through hole and the metal film.
(a), (b), and (c) are the same as those shown in FIG.
The same numbers as in (a), (b), and (c) are given (however, only the parts necessary for the description are omitted, and others are omitted).

As shown in FIGS. 5 (a) and 5 (b), first, on the glass substrate 25, a heat dissipation layer 44 (hereinafter, referred to as an upper surface heat dissipation layer) which is formed in a narrow area almost half of the upper surface in this case as well. 44) in addition to the lower surface, but in the case of the lower surface, the entire lower surface,
A heat radiation layer 48 (hereinafter, referred to as a lower heat radiation layer 48) is formed.

In the upper heat radiation layer 44, a notch 27 is formed in a portion where the ink supply groove 33 shown in FIG. 4C is to be formed in a later step, and after completion as a thermal ink jet head. In the exposed portion 44a exposed at the left end of the glass substrate 25, a through hole 51 is formed that penetrates the glass substrate 25 from the upper heat radiation layer 44 and opens to the surface of the lower heat radiation layer 48. A metal film 52 is formed on the edge of the opening and the inner wall.

The through holes 51 are formed by sandblasting on the upper and lower surfaces of the glass substrate 25, similarly to the ink supply grooves 33 and the ink supply holes 34 to be formed later. Further, the metal film 52 is formed in the through hole 51.
A resist is applied to portions excluding the upper and lower opening edges and the inner wall, and then a film is formed by electroless plating. The upper surface heat dissipation layer 44 and the lower surface heat dissipation layer 48 are physically (ie, thermally) connected (thermally coupled) by the metal film 52.

Thereafter, as shown in FIG. 3C, the glass substrate 25 is attached to the die bonding agent 39 via the lower heat radiation layer 48.
The ink jet print head 53 in a practical unit is completed by die bonding to the heat sink 37. In this configuration, the heat transmitted to the upper heat radiation layer 44 by the heat generated by the heat generating resistor 29 a is well transmitted to the lower heat radiation layer 48 by the metal film 52 on the wall surface of the through hole 51, and from the lower heat radiation layer 48 via the heat radiation plate 37. And is efficiently radiated to the outside.

FIGS. 6A and 6B are views for explaining a modification of the thermal ink jet head according to the third embodiment. As shown in FIG. 6 (a), FIG.
(c) After creating a thing having the same shape as the configuration of the thermal ink-jet head 53 shown in FIG. 1 and die-bonding the large-sized heat radiation plate 37, when cutting each ink-jet print head as an individual head chip with a dicing saw or the like, As shown by H-H 'in FIG. 3A, the main portion 53-1 and the end portion 5 extend along the longitudinal center line of the through hole 51.
3-2, the end portion 53-2 is discarded, and the main portion 53-2 is discarded.
-1 is the ink jet head 55 shown in FIG. FIG. 6B is an enlarged cross-sectional view taken along the line JJ ′ after the end 53-2 of FIG.

The shape of the ink jet head 55 is as follows.
A metal film 52 (a half surface of the metal film 52 formed on both surfaces of the inner wall of the through hole 51 in FIG. 6A) is formed on the end surface of the glass substrate 25. Even if the inkjet head 55 is formed in this manner, the heating resistor 29a
The heat radiated from the substrate can be efficiently transmitted to the back surface of the substrate and dissipated to the outside, and the entirety can be formed in a small size by separating the end portion 53-2. Can contribute.

The above-described modified examples of the second embodiment, the third embodiment, and the modified examples of the third embodiment each have a shape in which a heat dissipation layer is filled in a groove on the upper surface of a glass substrate. Although the case is illustrated, the present invention is not limited to this, and it is needless to say that the present invention can be applied to a case where the heat radiation layer is laminated on the upper surface of the glass substrate as in the first embodiment.

FIG. 7A is a plan view showing the state of formation of the upper heat radiation layer during the manufacturing process of the thermal ink jet head according to the fourth embodiment, and FIG. 7B is a plan view of FIG. FIG. 3C is a view showing the lower heat dissipation layer in a sectional view taken along the line KK ′, and FIG. 3C is an enlarged view of the portion shown in FIG. The configuration shown in FIGS. 7A, 7B, and 7C is the same as the configuration shown in FIGS. 5A, 5B, and 5C except for the heat conducting member. 5 (a), 5 (b), and 5 (c) are assigned the same reference numerals as those in FIG. 5 (however, only the parts necessary for the description are omitted and others are omitted).

As shown in FIGS. 7 (a) and 7 (b), in this embodiment, the upper heat radiation layer 44, the cutout hole 27, and the lower heat radiation layer 48 are provided in the same manner as in FIGS. 5 (a) and 5 (b). , Through holes 51 and the like are formed, but the inner wall of the through holes 51 is formed as shown in FIGS.
The metal film 52 as shown in (c) is not formed. Then, instead of the metal film 52, as shown in FIG.
The heat conduction member 56 is filled in the through hole 51.

After the ink jet head 57 completed on the glass substrate 25 is die-bonded to the heat radiating plate 37 as shown in FIG. Alternatively, it is formed by pouring a resin containing metal particles into the through hole 51 and curing the resin.

The heat conduction member 56 is provided in the through hole 51.
Is formed by filling the through holes 51
Since the method is easier than attaching the metal film 52 to the inner wall, there is an advantage that the productivity is excellent. In this way, by filling the through hole 51 with the heat conductive member 56, not only the upper surface heat dissipation layer 44 and the lower surface heat dissipation layer 48 on both surfaces of the glass substrate 25 but also the heat dissipation plate 37 directly and widely without the interposition of the die bonding agent 39. It becomes possible to perform thermal bonding. Also in this case, the heat radiated from the heating resistor 29a on the upper surface of the substrate can be efficiently transmitted to the rear surface of the substrate and radiated to the outside.

This structure can be applied not only to the case where the heat radiation layer is filled in the groove on the upper surface of the glass substrate as described above, but also to the case where the heat radiation layer is laminated on the upper surface of the glass substrate. Of course.

[0064]

As described above in detail, according to the present invention, since the heat radiation layer on the upper surface of the glass substrate is formed only below the common electrode and the heating resistor and not on the lower layer of the individual electrodes, high speed operation is achieved. Even if a defect such as a pinhole occurs in the insulating layer, it is possible to prevent the individual electrodes from being short-circuited via the heat dissipation layer by performing a proper film formation. With the heat radiation layer having a special shape, it is possible to provide a thermal ink jet head having extremely low short circuit occurrence.

Since the heat radiation layer on the surface of the substrate is thermally coupled to the heat radiation portion on the lower surface of the substrate by the heat transfer member, even if the heat radiation layer has a narrow shape which does not spread to the lower layer of the individual electrode, the heat radiation is not affected. The heat of the layer can be efficiently transmitted to the back surface of the substrate, and thereby, the high heat radiation characteristics of the narrow heat radiation layer can be maintained.

[Brief description of the drawings]

FIG. 1A is a plan view showing a state of forming a heat radiation layer during a manufacturing process of a thermal inkjet head according to a first embodiment, FIG. 1B is a cross-sectional view taken along the line CC ′ of FIG. (c) is
FIG. 3B is an enlarged view after completion of the thermal inkjet head.

FIGS. 2A and 2B are diagrams illustrating a reason why a heat radiation layer is removed from a lower layer of an individual electrode. FIG. 2A is a diagram illustrating a wiping member mounted on a printer body together with an inkjet head module, and FIG. FIG. 4 is a diagram showing the completed inkjet head in dimensional correspondence with a wiping member.

3A is a plan view showing a state of forming a heat radiation layer during a manufacturing process of a thermal inkjet head according to a second embodiment, FIG. 3B is a cross-sectional view taken along the line DD ′ of FIG. (c) is
FIG. 3B is an enlarged view after completion of the thermal inkjet head.

FIG. 4 is a diagram showing a modification of the second embodiment, and FIG.
Is a plan view showing the shape of the heat dissipation layer, (b) is a sectional view taken along the line EE 'of (a), (c) is a sectional view taken along the line FF' of (b), and FIG.
FIG. 4 is an enlarged view of a portion shown in FIG. 5B after completion of the thermal inkjet head, and FIG. 5E is an enlarged view of a portion shown in FIG.

FIG. 5A is a plan view showing a state of formation of an upper heat dissipation layer during a manufacturing process of a thermal inkjet head according to a third embodiment, and FIG. 5B is a sectional view taken along the line GG ′ of FIG. FIG. 4C also shows the lower heat dissipation layer, and FIG. 4C is an enlarged view of the portion shown in FIG.

FIGS. 6A and 6B are diagrams illustrating a modification of the thermal inkjet head according to the third embodiment.

FIG. 7A is a plan view showing a state of formation of a top heat dissipation layer during a manufacturing process of a thermal ink jet head according to a fourth embodiment, and FIG. 7B is a sectional view taken along the line KK 'of FIG. FIG. 4C also shows the lower heat dissipation layer, and FIG. 4C is an enlarged view of the portion shown in FIG.

FIGS. 8A, 8B, and 8C are diagrams showing a basic method of manufacturing a conventional thermal ink jet head in the order of steps (part 1).
It is.

FIGS. 9A, 9B, and 9C are diagrams showing a basic method of manufacturing a conventional thermal inkjet head in the order of steps (part 2).
It is.

FIG. 10 is a side sectional view of a conventional completed thermal inkjet head module.

FIGS. 11A and 11B are diagrams showing a configuration of a main part of a conventional thermal inkjet head improved by the present applicant.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Glass substrate 2, 2 'heat radiation layer 3 Insulating layer 4 Heating resistance film 4a Heating resistor 5 Individual electrode 6 Common electrode 7 Opening 8 Partition wall 9 Ink supply groove 11 Ink supply hole 12 Orifice plate 13 Ink channel 14 Metal film 15 Orifice Pattern 16 Orifice 17 Thermal inkjet head 18 Driver IC 19 TCP 21 Heat sink 22 Ink supply port 23 Die bonding agent 24 Thermal inkjet head module 25 Glass substrate 26 Heat dissipation layer 27 Notch hole 28 Insulating layer 29 Heating resistance film 29a Heating resistor 31 Electrode film 31a Individual electrode 31b Common electrode 32 Partition wall 33 Ink supply groove 34 Ink supply hole 35 Orifice plate 36 Orifice 37 Heat dissipation plate 38 Ink supply port 39 Die bonding agent 40 Inkjet head module 41 Heat Transfer Paste 42 Wiping Member 43 Blade 44 Heat Dissipation Layer (Upper Heat Dissipation Layer) 44a Exposed Portion 45 Groove 46 Ink Supply Groove 47 Heat Dissipation Layer 47a Connection 47b Connection 48 Heat Dissipation Layer (Lower Heat Dissipation Layer) 51 Through Hole 52 Metal Film 53 Thermal inkjet head 53-1 Main part 53-2 End part 55 Thermal inkjet head 56 Thermal conductive member 57 Thermal inkjet head

Claims (6)

[Claims] An orifice plate provided with a heat dissipation layer, an insulating layer, a heating resistor, a signal electrode and a common electrode layer, a partition, and an orifice is sequentially laminated on one surface of a substrate, and is formed on the one surface of the substrate. And a heat radiator is arranged on the opposite side, and the voltage is applied between the signal electrode and the common electrode to cause the heat generating resistor to generate heat, thereby causing film boiling at the interface between the heat generating resistor and the ink. In a thermal ink jet head for discharging ink from the orifice to the outside, the heat radiation layer is provided at a position except for a lower layer portion of the signal electrode, and includes a heat conductor that thermally couples the heat radiation layer and the heat radiation body. A thermal inkjet head characterized by the following. 2. The thermal device according to claim 1, wherein the heat radiation layer thermally coupled to the heat radiator via the heat conductor is provided in a groove formed on the one surface of the substrate. Ink jet head. 3. The thermal ink jet head according to claim 1, wherein the heat transfer member is provided at an end of the substrate. 4. The thermal inkjet head according to claim 1, wherein the heat transfer member is provided so as to penetrate the substrate. 5. The thermal ink jet head according to claim 4, wherein the heat conductor is attached to a wall surface of a through hole formed in the substrate. 6. The thermal ink jet head according to claim 4, wherein the heat conductor is filled in a through hole formed in the substrate.