JP2007223330A - Thermal inkjet print head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermal inkjet print head with a heating resistor which is superior in cavitation resistance and has good heating efficiency. <P>SOLUTION: A heating resistor 30 comprises a lower layer 31 which contacts the substrate surface of a chip substrate 21, an intermediate layer 32 yielded by the annealing treatment of the lower layer 31, and a heat generating resistor layer 33 sticking to this. The lower layer 31 is formed by any of Ta-Si-O, Ta-Si-O-N, Ta-Si-Al-O, or Ta-Si-Al-O-N, and the heat generating resistor layer 33 is also formed by the same composition. A resistance R2 of the lower layer 31 has a relation of R2≥R1×10 with a resistance R1 of the heat generating resistor layer 33 and current hardly flows, and since only the thin heat generating resistor layer 33 generates heat, heating efficiency is excellent. In addition, since both compositions of them are the same, adhesion force is strong, and since a thickness adding both thicknesses d2 and d1 is made to become d1+d2≥4000Å, the heating resistor excels in cavitation resistance. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a thermal ink jet print head provided with a heating resistor that is excellent in cavitation resistance and does not decrease the heating efficiency.

  Conventionally, ink jet printers have been widely used. For the print head used in this ink jet printer, a thermal method in which ink is heated to generate bubbles and ink droplets are ejected by the pressure, a piezo method in which ink droplets are ejected by deformation of a piezoresistive element (piezoelectric element), etc. There is a print head.

  Since these inks, which are color materials, are ejected directly onto recording paper as ink droplets for printing, printing energy is low when compared with electrophotographic systems that use toner, which is a powdery printing material. The color mixture can be easily made by mixing, and since the print dots can be made small, the image quality is high and the noise is extremely low, so that it is widely used especially as a print head for a personal printer.

  The above-described thermal type print head is called a thermal ink jet print head, and there are two configurations depending on the ejection direction of ink droplets. One is called a side shooter type that discharges ink droplets in a direction parallel to the heat generating surface of the heat generating element, and the other is ink droplets in a direction perpendicular to the heat generating surface of the heat generating element. This is called a roof shooter type having a structure for discharging. It is known that this roof shooter type thermal ink jet print head consumes very little power and is economical compared to the side shooter type.

  FIG. 5A is a plan view schematically showing an ink discharge surface of a thermal ink jet print head disposed in such a roof shooter type ink jet printer, and FIG. The cross-sectional arrow view and FIG. 10 (c) are enlarged plan views transparently showing the internal structure.

  A thermal ink jet print head (hereinafter simply referred to as a print head) 1 shown in FIGS. 1A, 1B and 1C is formed on a chip substrate 2 which is partitioned in large numbers on a silicon wafer (not shown). It is formed by a processing technique and a thin film formation processing technique, and is cut out and collected from a silicon wafer after completion.

  As shown in FIG. 2A, four nozzle rows 3 for ejecting four types of inks of yellow, magenta, cyan and black are formed on the ink ejection surface of the print head 1. In one nozzle row 3, for example, if the print head 1 has a resolution of 600 dots / 25.4 mm, a large number of nozzles 4 are arranged in a vertical row at an arrangement pitch of 42.3 μm. Each nozzle row 3 is supplied with ink of a color corresponding to each nozzle row 3 from an unillustrated ink cartridge or the like.

  As shown in FIGS. 2B and 2C, the print head 1 has an internal structure in which a driving circuit 5 made of LSI and a heating resistor 6 made of a thin film are formed on a chip substrate 2, and this heating resistor is formed. An individual wiring electrode 7 that connects one end of the body 6 and the drive circuit 5 is formed, and further, a common electrode that connects the other end of the heating resistor 6 and a power supply terminal 8 (see FIG. 5A). 9 is formed. And the partition 11 (11a, 11b, 11c) is laminated | stacked on these. The heating resistors 6 and the individual drive electrodes 7 are arranged in the same number as the nozzles 4 of the nozzle row 3 formed later.

  An ink supply groove 12 extending parallel to the arrangement direction of the heating resistor 6 and an ink supply hole 13 communicating with the ink supply groove 12 and penetrating through the lower surface of the chip substrate 2 are formed. An orifice plate 14 is bonded and laminated on the partition wall 11 from above. By laminating the orifice plate 14, an ink flow path 15 having a height of approximately 10 μm corresponding to the thickness of the partition wall 11 is formed between the heating resistor 6 and the ink supply groove 12. Thereafter, the above-described nozzle 4 for ejecting ink is formed on the orifice plate 14.

  In the print head 1, ink is supplied from an external ink cartridge or the like to the heating resistor 6 through the ink supply hole 13, the ink supply groove 12, and the ink flow path 15 during printing. The drive circuit 5 selectively energizes the plurality of heating resistors 6 in accordance with the image information to generate a film bubble phenomenon that rapidly expands and disappears at the interface with the ink. Drops are ejected from the nozzle 4 toward the paper surface.

  6A, 6B, and 6C are diagrams showing the basic ink ejection operation of the print head 1. FIG. In this figure, the same components as those shown in FIGS. 5 (a), (b) and (c) are assigned the same numbers as in FIGS. 5 (a), (b) and (c). The whole is shown simply. First, in the standby state shown in FIG. 6 (a), the ink 16 supplied from the outside to the ink flow path 15 enters the nozzle 4 and enters the meniscus 16a at the upper opening of the nozzle 4 along the upper surface of the orifice plate. Is forming.

  Next, in order to eject the ink 16 from the nozzle 4, the heating resistor 6 is heated by energization according to the image information as described above, and as shown in FIG. The film bubbles 17 are generated. This film bubble 17 is formed by combining a large number of first generated nuclear bubbles.

  This film bubble 17 grows adiabatically and grows and pushes the surrounding ink 16, whereby the ink 16 b is pushed out from the nozzle 4, and the pushed ink 16 b is further transformed into an ink as shown in FIG. Droplets 16c are ejected from the nozzle 4 toward a recording medium (not shown). Thereafter, the grown film bubbles are contracted by the surrounding ink, and finally disappear. The ink 16 immediately after the ejection of the ink droplet 16 c forms a meniscus 16 a at the bottom of the nozzle 4. The meniscus 16 a is refilled in the nozzle 4 by the ink 16 being replenished to the ink flow path 15 from the outside. It rises and is restored to the standard standby state shown in (a).

  FIGS. 7A and 7B are diagrams schematically showing the process of bubble growth and disappearance related to the ejection of the ink droplets. The figure (a) shows the heating resistor 6 experimentally set in the open pool 18 with a water depth of 1 mm (millimeter) and the process of bubble growth and extinction by this until 0 to 6 μs (microseconds) every 1 μs. ing. FIG. 5B shows the energization timing to the heating resistor 6.

As shown in FIG. 6A, the heating resistor 6 is heated in 0 to 1 μs, the nuclear bubbles grow in 1 to 2 μs, and the ink droplets 16c shown in FIG. 6 are ejected from 2 to 3 μs. Bubbles 17 are generated, and the shrinkage of the bubbles has already started in 3 μs. Then, the pressure inside the bubble rapidly decreases until the bubble disappears in 6 μs, and cavitation with a negative pressure occurs as shown by arrows a-1, a-2, and a-3 in FIG. This cavitation works as a force to peel off the heating resistor 6 from the installation surface, and the impact force is said to reach 1000 ton / cm ² in the case of the above open pool with a water depth of 1 mm. Under such an operating environment, the heating resistor 6 is eventually destroyed by the impact of cavitation.

On the other hand, ensuring the life of the heating resistor 6 is an important issue. Therefore, a configuration has been considered that prevents the occurrence of the problem that the heating resistor 6 is destroyed by the impact of the cavitation as much as possible. Fig. 8 (a) is a diagram schematically showing the thickness of the heating resistor from before, that is, before the destructive action of the cavitation impact is clarified, and Fig. 8 (b) is the diagram showing the destruction of the cavitation impact. It is a figure which shows the example which formed the heat-generating resistor itself thickly in order to give resistance to an effect | action. The thickness of the heating resistor 6 'shown in FIG. 4 (a) is about 1000 to 5000 mm although it depends on the material. The heating resistor 6 ″ shown in FIG. 6B is formed by forming the heating resistor 6 ′ shown in FIG. In addition, it has been considered to provide a thick protective layer of about 3000 mm on the heating resistor 6 'shown in FIG.
JP-A-11-240156 (Summary, [0029], FIG. 3)

  However, if the heating resistor itself is formed thick, the resistance value of the heating resistor decreases as the thickness increases, and the heat generation performance decreases. If the heat generation performance decreases, a great amount of electric power is consumed to compensate for the low heat generation performance and obtain a desired heat generation. Therefore, it has a problem that it is not economical.

  Further, providing a thick protective layer on the heating resistor reduces the energy efficiency for heating the ink because the ink must be heated through the thick protective layer. Again, a great deal of power is consumed to compensate for the reduced energy efficiency and to obtain the desired heating performance. Therefore, it still has the problem that it is not economical.

  An object of the present invention is to provide a thermal ink jet print head provided with a heating resistor that has excellent cavitation resistance and good heat generation efficiency in view of the above-described conventional situation.

The configuration of the thermal ink jet print head according to the present invention will be described below.
The thermal ink jet print head of the present invention is a thermal ink jet print head that performs recording by discharging the ink in a predetermined direction by the pressure of bubbles generated by heating the ink with a heating resistor provided on the surface of the substrate. In addition, TaAB (provided that A is Si or Si—Al, B is O or O—N) is provided as a base high resistance layer in contact with the substrate surface, and TaAB (provided that A is Si or Si—) as a heating resistance layer thereon. Al, B are O or O—N), and when the resistance value of the base high resistance layer is R2 and the resistance value of the heat generation resistance layer is R1, “R1 × 10 ≦ R2”. When the thickness of the layer is d2 and the thickness of the heating resistor layer is d1, the R1 is maintained at the same level as the resistance when the d1 is 1000 mm, and the relationship of “d1 + d2 ≧ 4000 mm” is satisfied. An insulating layer made of Ta—Si—O is provided between the base high resistance layer and the heat generation resistance layer by annealing the base high resistance layer at 400 to 500 ° C. in the atmosphere. Composed.

  The base high resistance layer is configured such that the molar percentage of O or ON is larger than that of the heat generation resistance layer. The insulating layer preferably has a thickness of 2000 mm or less.

  According to the present invention, a heat generating portion having a thickness of at least 4000 mm that absorbs the distance at which hole destruction due to cavitation impact on the substrate proceeds is formed with a three-layer structure having strong adhesion strength, and the uppermost layer is a relatively thin heat generating resistor. And the intermediate insulating layer is formed by annealing the underlying high-resistance layer in the atmosphere, so that it is possible to provide a thermal inkjet printhead having a resistor with excellent cavitation resistance and heat generation efficiency Become.

Embodiments of the present invention will be described below with reference to the drawings.
(Embodiment 1)
FIG. 1 is a diagram showing a configuration of a heating resistor of a thermal ink jet print head in one embodiment. The thermal ink jet print head of this example is produced by the same method as the thermal ink jet print head 1 shown in FIG. 5 except that the production process of the heating resistor is different.

  As shown in FIG. 1, the heat generating portion 20 of the thermal ink jet print head of this example has a base high resistance layer 22 formed on a chip substrate 21 in contact with the substrate surface, and a heat generating resistance layer 23 in close contact therewith. It is formed as a heating resistor. The material composition of the base high resistance layer 22 is formed of Ta—Si—O, Ta—Si—O—N, Ta—Si—Al—O, or Ta—Si—Al—O—N.

  In addition, the material composition of the heating resistor layer 23 is also formed of Ta—Si—O, Ta—Si—O—N, Ta—Si—Al—O, or Ta—Si—Al—O—N, as described above. However, the heating resistance layer 23 and the above-described base high resistance layer 22 have greatly different electrical resistance values while having a very close composition.

  That is, when the resistance value of the base high resistance layer 22 is R2 and the resistance value of the heat generation resistance layer 23 is R1, each is configured to satisfy “R1 × 10 ≦ R2.” As will be described in detail later, this difference in resistance value can be realized only by changing the mol% of “O” or “O—N” in each composition.

  The total thickness of the base high resistance layer 22 and the heat generation resistance layer 23 is “d1 + d2 ≧ 4000 mm”, where d2 is the thickness of the base high resistance layer 22 and d1 is the thickness of the heat generation resistance layer 23. It is comprised so that it may become. The structure of the heating resistor portion having such a composition and thickness is the feature of the thermal ink jet print head of the present invention that is highly resistant to the destructive force of cavitation impact. In order to develop a thermal ink jet print head that is highly resistant to the destructive force of cavitation impact as described above, it was first started by investigating the mechanism of cavitation destruction. This will be described below.

In this investigation, first, a sample for cavitation destruction for investigating the mechanism of cavitation destruction was prepared as follows. First, a Ta—Si—O—N heating resistor film is formed by sputtering on a Si substrate on which a SiO ₂ insulating layer having a thickness of about 1 μm is previously formed. The film thickness was 1000 mm. On this, a wiring film having a three-layer structure including a W—Ti base wiring film, a Au main wiring film, and a W—Ti parent partition wiring film is formed.

  Thereafter, the wiring film and the heating resistor film are patterned to expose a portion to be a heating portion of the lower heating resistor film, that is, a portion to be a heating resistor, and electrode films are formed on both sides of the exposed heating resistor. Then, a patterned three-layer wiring is formed. The size of the heating resistor is 25 μm square. Further, a partition wall was formed so as to surround the heating resistor.

FIG. 2 is a graph showing a result of an experiment in which a thermal ink jet print head of a sample prepared as described above is placed in an open pool of water and a heat generation driving pulse is applied. The figure shows the number of heating drive pulses applied on the horizontal axis in 10 ⁸ units (the rightmost “1” indicates 100 million times), and the vertical axis shows the electrical resistance value of the sample heating resistor (hereinafter referred to as “the heating resistance”). The initial value is 1).

  In this experiment, the thermal ink jet print head described above is placed in an open pool of water and fixed on an appropriate table so that the water pressure is 1 mm, and 9 heats are randomly generated from a number of heating resistors as samples. The resistor chxx (ch01, ch09, ch17, ch25, ch33, ch41, ch49, ch57, ch65 in the example of the figure) was selected.

  Next, the foaming state is observed while changing the applied energy, and the applied energy that is 10% of the energy that maximizes the size of the bubbles is set. Under these setting conditions, the heat generation of 1 μsec at 10 KHz is applied to the nine heating resistors. A drive pulse was applied continuously for 10 million pulses, and the rate of change in resistance value was measured before and after that. Then, the continuous pulse application of 10 million times was repeated 10 times to apply a total of 100 million heat generation driving pulses. As a result, approximately 80 million times, one heating resistor, for example, the heating resistor ch09, was disconnected (see f in FIG. 2).

  Each of the heating resistors chxx is normalized to a constant value with an initial average resistance value. The heating resistor ch09 that was disconnected by the above 80 million applied pulses showed almost no change in resistance value until just before the disconnection, and was 3% or less. Moreover, the change of the resistance value of the remaining other heating resistors chxx that did not lead to disconnection was 5% or less. When the sample after the application of 100 million pulses was observed with an optical microscope, abnormalities were observed in the other heating resistors chxx other than the disconnected heating resistor ch09.

  FIGS. 3A, 3B, and 3C are diagrams schematically showing findings obtained by observation with the scanning electron microscope (SEM) with respect to the above-described disconnection location and other abnormal locations. According to this observation, as shown in FIG. 6A, in the heating resistor chxx at the abnormal location, a hole 24 is formed in a part of the heating resistor chxx, and the hole 24 reaches the substrate 26 side. It was. The depth of the hole 24 is about 3000 mm.

  Further, in the heating resistor ch09 at the disconnection portion, as shown in FIG. 5C, the entire destruction 27 was observed in the direction perpendicular to the current. When this part was subjected to surface analysis by EPMA, it was found that the heat generation resistive film in the broken part was peeled off and disappeared, and the substrate surface was exposed. Further, when this exposed portion was observed, it was observed that a hole 24 having a depth of about 3000 mm was also formed in this exposed portion.

  Summarizing the above observation results, (1) the resistance value of the heating resistor hardly changes until immediately before disconnection. (2) A hole reaching the substrate is formed before the disconnection (see FIG. 3A). (3) The number of holes increases sequentially (see FIG. 3 (b)). (4) Destruction progresses in a horizontal direction around these holes (see FIG. 3 (c)). The model can be considered.

  The “lateral direction” is defined as a direction perpendicular to the direction of the current flowing through the heating resistor and parallel to the substrate. The hole breakage reaches the substrate and proceeds to a depth of about 3000 mm. However, the lateral breakage occurs only at the heating resistor and proceeds until the substrate surface is exposed, but reaches the inside of the substrate. It turns out not to.

  In the above model, in order to confirm that the resistance hardly changes until just before the disconnection, the size of the hole reaching the substrate is set to 1/10 of the size of the heating resistor, and this size causes the disconnection in the lateral direction. When the rate of change of the resistance value when progressing was calculated, the rate of change of the resistance value when breaking progressed to about 30% in the lateral direction was about 5%. This means that the resistance change is about 5% when three holes of 1/10 the size of the heating resistor are arranged in a straight line in the horizontal direction.

  Therefore, the calculation result described above is that a plurality of holes are formed by cavitation breakage, the breakage progresses at once in the lateral direction around these holes, and the change in resistance value is small until just before the breakage. Matches well with the model. In addition to the damage of the actual heating resistor, it has been observed that the wiring electrode is broken and retracted from the initial connection position, but this effect is not the main point of the present invention. I won't touch it here.

  In any case, from the results of the above observation and calculation, in order to extend the life of the heating resistor, the film thickness may be increased. For example, in order to prevent the holes from reaching the substrate surface, it was considered that the film thickness should be at least 4000 mm. In order to confirm this, a heating resistor having the same film quality as that described above and a thickness of about 4000 mm was formed, and an experiment similar to the above was conducted. It was zero.

  However, as described above, it is not desirable to increase the thickness of the heating resistor because it consumes a large amount of power. For example, when a heating resistor having a film thickness of 1000 mm and a sheet resistance of 100 Ω / sqr is formed into a square, the resistance value becomes 100 Ω. When ink is ejected with energy of 1 μJ using this heating resistor, the current is 100 mA. On the other hand, when a heating resistor having the same film quality and a film thickness of 4 times is produced, the resistance value is 25Ω, and the drive current in this case is 200 mA. Thus, as the resistance value of the heating resistor decreases, a driver with a large current is required to drive the heating resistor, which is not practical in practice.

  Therefore, it was decided to aim at a method of forming a total thickness of 4000 mm or more while maintaining the resistance value of the heating resistor at the same level as the resistance value when the thickness was 1000 mm. The structure obtained as a result is the structure of the heat generating portion 20 shown in FIG.

  That is, the base high resistance layer 22 having a higher resistance is disposed under the heat generation resistance layer 23 serving as a heat generation resistor to form a heat generating portion having a substantially thick film thickness. For example, the resistance value of a Ta—Si—O-based or Ta—Si—O—N-based resistor can be increased by increasing the amount of O or ON (mol%). Specifically, for example, in the case of Ta—Si—O, the resistivity is increased by about one digit by increasing the amount of oxygen from 30% in the case of a normal heating resistor to 50%.

  That is, when the oxygen amount of the heat generating resistance layer 23 is 30 mol% and the resistance value is R1, when the base high resistance layer 22 is formed so that the oxygen amount is 50 mol%, the resistance value R2 is “R2 ≧ R1 × 10”. In this way, the resistance value can be changed (high resistance) by simply changing (increasing) the amount of oxygen using the same composition of the Ta—Si—O system.

  When the oxygen amount is further increased to 60%, the resistance value increases by several orders of magnitude. However, if the resistance value of the base high resistance layer 22 can be increased by an order of magnitude over the resistance value of the heat generation resistance layer 23, the original development purpose can be achieved.

  Further, it has been experimentally found that this resistance value changing method increases the resistance due to the increase of “oxygen + nitrogen” even when the composition of the thin film is Ta—Si—O—N. However, although the resistance characteristic shows a complicated behavior depending on the ratio of oxygen and nitrogen, there is no change in increasing the resistance value due to the increase of “oxygen + nitrogen”.

  The one heating resistor layer 23 is compositionally set so that the resistance value R1 thereof becomes the resistance value of a normal heating resistor. On the other hand, the resistance value R2 of the lower base high resistance layer 22 is very high resistance such that “R2 ≧ R1 × 10”, so that almost no current flows, and energy loss in this portion can be ignored. belongs to.

  Therefore, even in such a continuous two-layer structure, the resistance value of the heat generating resistance layer 23 is slightly lower than that in the case of a single one-layer structure, but remains at a reduction rate of 9% or less. There is no serious loss. That is, heat is efficiently generated by applying the drive voltage, and ink is efficiently discharged.

  As described above, the base high resistance layer 22 and the heat generation resistance layer 23 are almost independent from each other when viewed electrically. Since they have the same composition but only different, the adhesion at the interface is very strong. This is presumably because the amorphous states of both are similar (the X-ray diffraction broad patterns are similar).

  As described above, the adhesiveness at the interface between the underlying high resistance layer 22 and the heating resistance layer 23 is extremely strong, and therefore, the upper heating resistance layer 23 can be easily peeled off against the negative pressure of cavitation impact. There is no. In addition, since the total thickness of both of the thicknesses d2 and d1 is formed to be 4000 mm or more, even if the hole due to cavitation breaks up to 3000 mm with 100 million drive pulses. , The holes do not reach the substrate surface, and thereby the adhesion between the heat generating portion and the substrate surface is not impaired, and therefore the lateral destruction is not induced.

(Embodiment 2)
FIG. 4 is a diagram illustrating a configuration of a heat generating portion of a thermal ink jet print head according to another embodiment. In the heating resistor 30 shown in the figure, a lower layer 31, an intermediate layer 32, and a heating resistor layer 33 are formed on the uppermost layer on a chip substrate 21. The uppermost heating resistance layer 33 is a thin film having a Ta—Si—O-based or Ta—Si—O—N-based composition, and the lower layer 31 is a thin film having substantially the same composition as the heating resistance layer 33. The intermediate layer 32 is an Ta—Si—O-based composition having an oxygen content of about 70 mol% and a thickness of about 50 to 100 mm.

  The intermediate layer 32 is obtained by annealing the Ta—Si—O or Ta—Si—O—N of the lower layer 31 at 400 to 500 ° C. in the atmosphere. In this case as well, the Ta—Si—O film intermediate insulating layer (intermediate layer 32) and the upper and lower Ta—Si—O film or Ta—Si—O—N heat generating resistor layer 33 and lower layer 31 are in close contact with each other. Sex is powerful. However, in this case, it is unconfirmed whether the amorphous state of both is similar.

  In general, it is known that an insulating layer has a low cavitation resistance because it has a small elastic deformation region. Therefore, the insulating layer serving as the intermediate layer 32 should have a small thickness, and is preferably 2000 mm or less. Of course, also in this case, it is preferable that the film thickness of the entire three-layer structure is 4000 mm or more.

  Note that the lower layer of the two-layer structure of the heating resistance layer and the lower layer is a Ta—Si—O film having an oxygen amount of about 70 mol%, that is, focusing on only making the entire film thickness 4000 mm or more. An insulating layer may be used as a heat storage layer. In this case, although it is slightly inferior in terms of cavitation resistance as compared with the above-described embodiment, there is an advantage that the structure is simple, that is, the creation is easy from the viewpoint of the process.

  In each of the above-described embodiments, the description has been made taking the Ta—Si—O system or the Ta—Si—O—N system as an example. Even so, since the resistivity changes in accordance with the change in oxygen concentration, the above-described configuration can be applied.

It is a figure which shows the structure of the heating resistor of the thermal inkjet print head in one embodiment. It is a graph which shows the result of having experimented by putting the thermal inkjet print head of the created sample in the open pool of water, and applying the exothermic drive pulse. (a), (b), (c) is a figure which shows typically the observation which performed the observation by the scanning electron microscope (SEM) with respect to a disconnection location and another abnormal location. It is a figure which shows the structure of the heating resistor of the thermal inkjet print head in other embodiment. (a) is a plan view schematically showing an ink discharge surface of a conventional thermal ink jet print head, (b) is a cross-sectional view taken along the line AA ′, and (c) is an enlarged plan view showing its internal structure in perspective. FIG. (a), (b), (c) is a diagram showing a basic ink discharge operation of the print head. (a), (b) is a figure which shows typically the process of the growth and extinction of the bubble which concern on discharge of the ink droplet of a print head. (a) is a figure which shows typically the thickness of the conventional heating resistor, (b) is a figure which shows the example which formed the heating resistor itself thickly to cope with a cavitation impact.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Thermal inkjet print head 2 Chip board 3 Nozzle row | line | column 4 Nozzle 5 Drive circuit 6, 6 ', 6 "Heating resistor 7 Individual wiring electrode 9 Common electrode 11 (11a, 11b, 11c) Partition 12 Ink supply groove 13 Ink supply hole DESCRIPTION OF SYMBOLS 14 Orifice plate 15 Ink flow path 16 Ink 16a Meniscus 16b Ink 16c Ink droplet 17 Membrane bubble 20 Heat generating part 21 Chip substrate 22 Underlying high resistance layer 23 Heat generating resistance layer 24 Hole 26 Substrate 27 Destruction 30 Heat generating resistor 31 Lower layer 32 Intermediate layer 33 Heat resistance layer

Claims (3)

A thermal ink jet print head that performs recording by discharging the ink in a predetermined direction by the pressure of bubbles generated by heating the ink with a heating resistor provided on the surface of the substrate,
TaAB (provided that A is Si or Si—Al, B is O or O—N) is provided as a base high-resistance layer in contact with the substrate surface, and TaAB (provided that A is Si or Si—Al) as a heating resistance layer thereon. , B is O or O-N),
When the resistance value of the base high resistance layer is R2 and the resistance value of the heating resistance layer is R1,
R1 × 10 ≦ R2
And
When the thickness of the base high resistance layer is d2 and the thickness of the heating resistance layer is d1, the R1 is maintained at the same level as the resistance value when the d1 is 1000 mm,
d1 + d2 ≧ 4000cm
Have the relationship
An insulating layer made of Ta—Si—O is provided between the base high resistance layer and the heat generation resistance layer by annealing the base high resistance layer at 400 to 500 ° C. in the atmosphere. Inkjet printhead.   The thermal ink jet print head according to claim 1, wherein the base high resistance layer has a larger mol% of O or O—N than the heat generation resistance layer.   2. The thermal ink jet print head according to claim 1, wherein the insulating layer has a thickness of 2000 mm or less.

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