JPH04251750A - Ink-jet recording head - Google Patents

Abstract

PURPOSE:To thin and miniaturize a recording head while stabilizing printing quality, and to facilitate handling and maintenance. CONSTITUTION:A plurality of ink nozzles 22 constituting a Kayser type on- demand type recording head are juxtaposed onto the same substrate 17. An ink flow path is washed by alkali as required, and water-repellent films are formed to ink discharge openings, thus varying and adjusting the wettability of ink. A heater is installed for heating at the time of an atmosphere at a low temperature for keeping the viscosity of ink at a fixed value or less at all times. A recording head body and an ink tank are unified and changed into a cartridge while a cap covering the ink discharge openings is added.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inkjet recording head used in analog recorders and the like, and more particularly to a recording head comprising a plurality of ink nozzles constituting a Kaiser type on-demand inkjet recording head.

0002

[Prior Art] Conventional analog printing recorders have the advantage of being able to intuitively grasp changes in temperature, pressure, etc. input from the measurement target, and are therefore useful for industrial applications such as measurement and instrumentation control systems. It is widely used as a means of data recording, monitoring, and storage in the industrial field as well as in development and research departments. These recorders are equipped with various recording heads, and print signals input from the outside as lines or characters on recording paper or the like. Here, there are various types of recording heads depending on their printing methods. Representative examples will be explained below.

(2) A wire dot type recording head is composed of an ink ribbon, a wire portion, and an electromagnetic hammer. When a recording pulse is applied, the electromagnetic hammer shoots out a wire and transfers ink from the ink ribbon onto recording paper. When printing dots as analog data, one stamp is sufficient, but when printing characters, 8 to 25 stamps are required for each digit. When printing in color, multiple ink ribbons of different colors are prepared and the ink ribbons are changed according to the color to be printed. (2) Thermal head method A recording head is constructed by forming a plurality of recording electrodes made of heat generating resistors on an insulating plate. The recording paper used is paper coated with a chemical that develops color through a thermal reaction. When printing dots as analog data, a pulse is applied to one electrode corresponding to the measured value, causing it to heat and develop color. When printing a character, a pulse is applied to the electrode at the position corresponding to the character to heat and color it. ■Pen printing method A recording pen is used in the recording head and is controlled by electrical signals to print. When printing analog data, continuous recording can be performed by tracing by touching the recording pen to the paper surface. When printing a character, it is necessary to repeatedly strike a dot at a position corresponding to the character using the pen's up-and-down mechanism, 8 to 25 times per digit of the number.

[0004] FIG. 13 shows an example of an inkjet recording head using a so-called Gould type recording head. In the figure, 1 is a head nozzle section, 2 is a nozzle plate, 3 is an ink tank, and 4 is a recording paper as a recording medium. FIG. 14 is an enlarged view of the head nozzle part 1, and in the figure, 5 is a piezoelectric element cylinder;
6 is a glass tube whose inside becomes a liquid chamber, 7 is an orifice, and 8 is a filter. This head nozzle part 1 has a glass tube 6 fitted into a piezoelectric element cylinder 5.
Electrodes (not shown) are formed on the inner and outer surfaces and are connected to an external power source. When a pulsed voltage is applied to this piezoelectric element cylinder 5, the liquid chamber inside the inner glass tube 6 contracts and its volume decreases. As a result, the ink supplied from the external ink tank 3 via the filter 8 is ejected from the nozzle plate 2 to the outside through the orifice 7 and prints dots on the recording paper 4. Line drawings and characters are drawn by printing while changing the relative position between the recording paper 4 and the head nozzle section 1. In the recording head shown in Figure 13, nozzles for ejecting three colors of cyan, magenta, and yellow ink are arranged in a horizontal line for analog use, and eight black ink nozzles are arranged in two vertical rows for character use. be done. Ink of each color is supplied to these nozzles from an ink bag stored in an ink tank 3 via a supply tube.

When analog data is printed by this Gould type recording head, ink is ejected according to the above-mentioned driving principle at the timing when the respective mechanical positions and measured values coincide, and the dots of the three colors are printed on the recording paper 4. printed on top. In addition, by combining the three colors above, purple,
Green and orange colors are combined, making it possible to print in a total of six colors. Further, when printing characters, characters such as alphanumeric characters are printed by applying a pulsed voltage at a predetermined timing to the nozzle section 1 dedicated to characters that ejects black ink.

[0006]

By the way, each of the above-mentioned conventional printing methods has the characteristics shown in Table 1 below.

[0007]

[Table 1]

[0008] As can be seen from these comparisons, the inkjet method is superior to the conventional printing methods, and therefore the Gould type inkjet recording head is most commonly used in various recorders. However, this Gould type inkjet recording head has the following problems.

(2) A cylindrical piezoelectric element is used as a driving source for ejecting ink, and in order to downsize the recording head, the cylindrical piezoelectric element must be downsized. However, in order to manufacture a cylindrical body by reducing the outer and inner diameters of the piezoelectric material and further form an inner electrode on the inner circumferential surface, advanced microfabrication technology is required. It can only be produced up to Therefore, the limit for miniaturization of the recording head is the size using a piezoelectric element cylinder having an outer diameter of 1 mm. ■If you try to give a recording head a multicolor printing function, you will need as many piezoelectric element cylinders, or head nozzles, as many colors as you want to use.
It becomes large and runs counter to the demand for miniaturization. ■As a general structure, a nozzle plate is attached to the front of the orifice and assembled, so the orifice and the minute holes formed in the nozzle plate must be precisely aligned. Therefore, the yield in this process is poor, and the cost of the entire recording head increases accordingly.

The present invention has been made to solve the various problems of the above-mentioned Gould type recording head, and its purpose is to reduce the thickness, size, and cost of the recording head. Moreover, it is an object of the present invention to provide an inkjet recording head with improved printing quality.

[0011]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a Kaiser type on-demand type ink jet recording head in which a plurality of ink nozzles are arranged side by side on the same substrate.

[0012] Here, the substrate is formed of silicon, an ink flow path communicating with the ink nozzle is carved on the surface of the substrate by dry plasma etching, and a glass plate as a diaphragm is statically mounted on the top surface of the substrate. Electrical bonding is preferred. In addition, the surface of the ink flow path is cleaned with alkali,
It is desirable to form a water-repellent coating on the end surface of the substrate around the ink ejection ports. Furthermore, a notch having a cross-sectional area larger than the cross-sectional area of the ink nozzle may be formed on the end surface of the substrate between adjacent ink ejection ports, and a heater may be arranged on the surface of the substrate where the ink flow path is located. It's okay. In addition, the recording head and the ink tank for supplying ink may be housed in the same container to form a removable cartridge, and a cap that can be rotated to cover the ink ejection port may be provided at the front of the cartridge. good.

[0013]

[Operation] In the present invention, the ink nozzles constituting the Kaiser type on-demand type inkjet recording head are
By arranging a plurality of recording heads in parallel on the same substrate, it is possible to print in multiple colors, and the entire recording head can be made thin and compact. Furthermore, since the main parts of the head are formed centrally on the substrate, manufacturing is easy and costs can be reduced.

[0014] Here, if the substrate is formed of a silicon substrate, and an ink flow path is carved on the surface of the silicon substrate by dry plasma etching, and a glass plate is electrostatically bonded thereon, processing becomes easier. In addition, if the surface of the ink channel formed on the substrate is cleaned with alkali and a water-repellent film is formed on the end surface of the substrate around the ink ejection port, the wettability between the ink and the channel will increase within the ink channel. Air bubbles in the ink can be easily removed, and on the other hand, the wettability of the end surface of the substrate around the ink ejection ports is reduced, thereby preventing ink from adhering and accumulating. Further, by forming a notch having a cross-sectional area larger than the cross-sectional area of the ink nozzle between the ink ejection ports, it is possible to prevent ink from flowing along the end surfaces between the ink ejection ports and mixing with each other. Further, by installing a heater on the surface of the substrate where the ink flow path is located and indirectly heating the ink when the ambient temperature drops, it is possible to prevent the ink from solidifying due to an increase in viscosity. Furthermore, by accommodating the recording head main body and the ink tank in the same container to form a cartridge, it becomes possible to replace and handle only the cartridge. Further, by rotatably supporting the cap at the front of the cartridge, the cap can be rotated to cover the ink ejection opening when not in use, thereby preventing changes in the physical properties of the ink.

[0015]

Embodiments Hereinafter, embodiments of the present invention will be explained with reference to the drawings. First, FIG. 2 is an explanatory diagram showing the basic configuration of a Kaiser type on-demand type inkjet recording head used in this embodiment. In the figure, 9 is an ink tank;
10 is an ink supply path, 11 is an ink pressure chamber, 12 is an ink nozzle, 13 is an ink supply path communicating with the ink nozzle 12, 14 is a diaphragm provided outside the ink pressure chamber 11, and 15 is a diaphragm A piezoelectric element as an electromechanical transducer is attached to the diaphragm 14, and the diaphragm 14 and the piezoelectric element 15 constitute a bimorph. 16 is a head substrate, and ink supply channels 10, 1 are provided on this head substrate 16.
3, an ink pressurizing chamber 11, and an ink nozzle 12 are formed. In the above configuration, when a pulse voltage is applied to the piezoelectric element 15, the piezoelectric element 15 expands in its thickness direction and contracts in its length direction, and the diaphragm 14 is deflected inward of the ink pressurizing chamber 11. . As a result, the ink pressurizing chamber 11
The volume of the diaphragm 14 decreases slightly, and the ink in the ink pressurizing chamber 11 becomes ink droplets due to pressure waves generated by the deformation of the diaphragm 14, and is ejected from the ink ejection opening of the ink nozzle 12 in the direction a in the figure.

Since the ink jet recording head shown in FIG. 2 can be formed entirely into a flat plate, even a recording head having a plurality of ink nozzles can be manufactured relatively thin and compact. Therefore, by arranging a plurality of ink nozzles in parallel on the same substrate, it becomes possible to realize an inkjet recording head that is capable of multicolor printing and is compact overall.

FIG. 1 is an exploded perspective view for explaining the structure of a first embodiment of the present invention, and FIG. 3 is a sectional view of FIG. 1. In these figures, 17 is a head substrate made of Si (silicon), and its thickness is 0.5 to 1.0 mm. On the surface of this head substrate 17, four sets of ink reservoirs 18, ink supply channels 19, 21, and ink pressurizing chambers 20 constituting ink flow paths are formed by dry plasma etching, and furthermore, ink nozzles 22 are continuously formed. It is formed by Here, the ink reservoir 18, the ink pressurizing chamber 20,
The ink supply path 21 extends from the head substrate 17 to a depth of 150 to 2
It is processed and formed in the range of 00 μm. Further, the cross section of the ink nozzle 22 has a width of 60 to 80 μm and a depth of 35 to 40 μm.
It has a semicircular shape of m, and its length is in the range of 0.3 to 0.8 mm. The depth of the ink supply path 19 is equal to the depth of the ink nozzle 2.
Form the same depth as 2. Further, the pitch L1 between the ink nozzles 22 arranged adjacent to each other is 1 mm.

After these parts are carved on the head substrate 17, a diaphragm 23 made of a glass plate is bonded to the upper surface of the diaphragm 23 by electrostatic bonding, thereby integrating the diaphragm 23 with the head substrate 17. Thereafter, a piezoelectric element 24 is attached to the upper surface of the diaphragm 23 corresponding to the position of the ink pressurizing chamber 20, forming the main part of the recording head. Although not shown, ink bags of four colors are respectively connected to the ink reservoir 18 via ink tubes. The ink supplied from these ink bags fills the ink reservoir 18 and is further sent to the ink pressurizing chamber 20 through the ink supply path 19. When a voltage pulse is applied to the piezoelectric element 24 attached to the diaphragm 23 on the top surface of the ink pressurizing chamber 20, the diaphragm 23 deforms and generates a pressure wave.
Ink is ejected from the ink ejection opening of the ink nozzle 22 as described in . In this example, it was confirmed that stable inkjet could be obtained when the frequency of the applied voltage pulse was up to 6 kHz. In this example, the material of the head substrate 17 was Si and various parts were processed by dry plasma etching. This is because it is the most superior compared to other processing methods.

Here, as a comparative example, the advantages and disadvantages of using photosensitive glass and stainless steel for the head substrate 17 will be explained. The photosensitive glass is made crystalline by irradiating only the ink flow path with light, then the crystalline part is etched with a hydrofluoric acid solution, and a photosensitive glass of the same quality as a diaphragm is superimposed on the head substrate. This was heated to around 500°C and bonded by thermal diffusion. In the case of stainless steel, the parts other than the ink channels were coated with a photosensitive resist and etched to the required depth with a hydrofluoric acid solution. After that, the stainless steel thin plates for the diaphragm were superimposed, and the
They were integrated by diffusion bonding in a vacuum atmosphere around °C. When photosensitive glass is used, the material is anisotropic, so the ink nozzle shape becomes trapezoidal, and the part where the ink nozzle and the ink supply path differ in depth becomes a steep step. , swirls of ink flow occurred in that area, creating problems in improving the response frequency and ensuring print quality. Furthermore, it was difficult to bond the diaphragm, and the bonding yield was extremely low, resulting in an economic disadvantage. In the case of stainless steel, although etching is possible, there are large variations in dimensions from lot to lot, and characteristics differ from print head to print head, making it unsatisfactory as a head for a recorder.

[0020]Next, the behavior and countermeasures taken when air bubbles enter the ink pressurizing chamber 20 in the first embodiment will be explained. As is well known, in this type of recording head, when ejecting ink by generating pressure waves, if the ink contains air bubbles, the generated pressure waves will be absorbed by the air bubbles, making it ineffective. There is. Therefore, in the second embodiment, in order to easily eliminate air bubbles that have entered the ink, a process is performed to increase the wettability of the surface of the ink flow path formed on the head substrate 17 to the ink. The wettability of this ink can be quantitatively expressed as the contact angle, so
Hereinafter, it will be explained as a contact angle. The inventors treated the surfaces of the head substrate 17 and the diaphragm 23 using various methods and conditions, and measured the contact angle with each ink under magnification using a microscope. Table 2 below shows typical results of these experiments, and it was confirmed that the contact angle was the smallest when the sample was immersed in an alkaline solution for 6 hours and then washed.

[0021]

[Table 2]

This alkaline solution contains potassium hydroxide (KO
H) The pH was adjusted by mixing dilution water with the solution. Furthermore, experiments with potassium hydroxide solution under different conditions showed that if the pH value was in the range of 12 to 14 and the immersion time was in the range of 5 to 12 hours, it had almost the same effect of reducing the contact angle. has been confirmed.

[0023] Through these processes, the ink supply path 21,
The contact angle of the ink flow path such as the ink nozzle 22 is reduced, and wettability is increased. As a result, the adhesion between the ink and the surface of the ink flow path increases, and the movement of air bubbles floating within the ink becomes easier. Specifically, if air bubbles enter the ink in the ink flow path, simply by pressing the blotting paper against the ink ejection opening of the ink nozzle 22, the air bubbles can be drawn together with the ink absorbed by the blotting paper and removed. Can be done. By removing air bubbles in this manner, it is possible to easily eliminate ink non-ejection due to the intrusion of air bubbles.

[0024] If the pH value is set to 12 or less as a condition for the above-mentioned alkaline cleaning, substantially the same effect can be obtained, but the treatment time until a sufficient effect is obtained becomes longer. Furthermore, even if the pH value is in the range of 12 to 14, if the treatment time is made longer than necessary, the surface will be eroded too much and the contact angle will become larger. Therefore, it is necessary to select the optimal combination of pH value and treatment time each time.

Next, a description will be given of how to deal with the case where ink remains attached to the periphery of the ink ejection opening of the ink nozzle 22 in the above-mentioned embodiment and print quality deteriorates. As is well known, in this type of inkjet recording head, the diaphragm 2
Ink is ejected only when 3 is deformed and a pressure wave is generated. That is, since ink droplets are intermittently ejected from the ink ejection ports, the ink should normally be interrupted at the ink ejection ports during a period when ink is not ejected. However, if ink is ejected many times over a long period of time, some of the ink may begin to adhere to the area around the ink ejection opening and gradually become larger. When such an ink pool occurs, when ink is ejected, the ink droplet ejected from the ink nozzle and the ink pool formed around the ejection port interact with each other, and the size of the ink droplet that reaches the paper surface becomes smaller. This may cause fluctuations or the generation of satellites (sub-ink droplets), impairing print quality.

Accordingly, as a third embodiment, a treatment to increase water repellency was applied to the end surfaces of the head substrate 17 and the diaphragm 23 around the ink discharge ports so that ink droplets would not adhere to the vicinity of the ink discharge ports. This water repellency is a property that contradicts wettability; the greater the water repellency, the more ink droplets are repelled and adhesion is prevented. Specifically, silicone oil is applied to the end surfaces of the head substrate 17 and the diaphragm 23 around the ink ejection ports, and
A water-repellent film is formed by heating and baking at 0 to 200°C for several hours. The thickness of the water-repellent film formed is 1μ
The water repellency against ink is sufficient. As a result of experiments, it was confirmed that even if printing was performed for a long time, ink did not stick to the printer, and no ink pools were formed, and high quality printing was maintained.

Next, a fourth embodiment of the present invention will be explained with reference to FIG. Similar to the third embodiment described above, this embodiment also prevents ink pools from forming around the ink ejection ports. In this embodiment, as shown in FIG. 4, the recording head itself is constructed almost the same as that in FIG.
25e is formed. These slits 25a to 25e
The width L2 is set to 60 to 80 μm, and is formed using a dicing cutter. In this way, by providing notches with slits 25 on both sides and in the middle of the ink discharge port, and by making the cross-sectional area of the notch larger than the cross-sectional area of the ink nozzle 22, ink will adhere to the periphery of the ink discharge port. Even if an ink pool is formed in the ink nozzle 22
This prevents the ink pool from expanding due to being pulled back. As a result, stable and high quality printing is always maintained. Furthermore, it is possible to completely prevent an ink pool formed around an ink ejection port from expanding to an adjacent ejection port and mixing different colors. The behavior of the ink under the interface and the relationship between the notch formed by the slit 25 for controlling the movement of the ink and its cross-sectional area were confirmed through experiments by the inventor.

Next, a fifth embodiment of the present invention will be explained with reference to FIG. Similarly to the third and fourth embodiments described above, this embodiment also prevents ink pools from forming around the ink discharge ports. This example, as shown in FIG.
When processing the head substrate 17 by dry plasma etching, grooves 26a to 26e are formed on both sides and intermediate portions of the ink nozzles 22a to 22d, and the groove width L3 is set to 80 to 80 mm.
It is set to 150 μm. The cross-sectional area of the notch formed by the grooves 26a to 26e is larger than the cross-sectional area of the ink nozzle 22. In this embodiment as well, stable and high-quality printing can always be maintained due to the same effect as in the fourth embodiment.

Next, a sixth embodiment of the present invention will be explained with reference to FIG. In this embodiment, stable printing quality can be maintained even if the ambient temperature of the recording head changes. The physical properties of ink change depending on temperature, and in particular, the ejection characteristics of an inkjet recording head are greatly influenced by the viscosity of ink. That is, when the temperature decreases and the viscosity of the ink increases, the frictional resistance in the ink flow path increases and the ink velocity decreases. At the same time, the amount of ink ejected also decreases, and print quality deteriorates. Usually, the ink temperature is 15
In the range of ~40°C, phenomena such as deterioration of printing due to changes in viscosity are not observed, and effects appear at temperatures lower than 15°C. Therefore, in this embodiment, the ambient temperature is 1
When the temperature drops below 5°C, the ink is indirectly heated to maintain the viscosity of the ink below a certain value.

That is, as shown in FIG. 6, in a recording head configured similarly to the first embodiment, the ink pressurizing chamber 2
A planar heater 27 is attached to the lower surface of the head substrate 17 at the position where 0 is formed. As is clear from the figure, the heater 27 is attached at the front and back sides of the piezoelectric element 24. As the heater 27, a PTC thermistor, a chip resistor, or the like is used. When the heater 27 is energized when the ambient temperature has decreased to a predetermined temperature, the ink in the ink pressurizing chamber 20 is indirectly heated and raised to a predetermined temperature. As a result, the viscosity of the ink is also maintained below a certain value, and a certain amount of ink is always ejected from the ink ejection opening, resulting in stable printing quality. In the inventor's experiments, even when the ambient temperature was 0°C, the heater 2
It has been confirmed that good printing can be achieved by heating according to No. 7.

Next, a seventh embodiment of the present invention will be explained with reference to FIG. In this embodiment, the attachment position of the heater 27 shown in the sixth embodiment is changed. That is, as shown in FIG. 7, the heater 28 is attached to the upper end of the diaphragm 23 above the ink nozzle 22, and the operation and effect of the heater 28 is almost the same as in the sixth embodiment. be. Particularly in the case of this embodiment, since the ink is heated by the heater 28 near the ink nozzle 22 immediately before it is ejected,
When printing is resumed after a pause in a low-temperature atmosphere, the start-up responsiveness of print quality is improved. Further, the nozzle ejection ports of colors that are used less frequently can be maintained at a constant temperature while the recorder is in operation, and deterioration of print quality can be prevented.

Next, FIGS. 8 and 9 show an eighth embodiment in which the above-described sixth embodiment is integrated with an ink tank into a cartridge so as to be easily attached to a recorder or the like. Specifically, the recording head main body 30 and the ink bag 31 that supplies ink to the main body 30 are integrated into a container 32 that is integrally formed.
The cartridge 33 is formed by being housed inside the cartridge. Inside the container 32, the main body 3 is inserted into the through hole at the bottom of the tip of the container 32.
The tip of 0 is inserted and supported. The other end of the main body 30 is fitted into a connector 34 and has a tube 35 connected to the ink bag 31.
connected to. Furthermore, the piezoelectric element 24 of the main body 30 is supported and fixed to the container 32 by a support member 36. Further, cords 37 and 38 are connected to the piezoelectric element 24 and the heater 27 of the main body 30, respectively, and the other ends are connected to a socket portion 39 at the right end of the container 32.

In this manner, the recording head main body 30 and the ink bag 31 are housed in the same container 32, and the cartridge 33 is
By forming this, the main body 30 and ink bag 31 can be attached and removed from a recorder, etc. with one touch, and can be replaced for inspection of the recording head, ink replenishment, etc.
Maintenance becomes easier. In particular, if a printing problem occurs while the recorder is in operation, by replacing the entire cartridge 33 in a short time, the printing interruption time can be minimized and the printing can be restored and continuity of recording can be maintained.

Next, FIGS. 10 to 12 show a ninth embodiment of the present invention, in which the structure of the cartridge 33 is different. The ink used in inkjet recording heads, whether water-based or oil-based, contains water and other solvents, and if the ink nozzle 22 is left in the air for a long time, the water and other solvents will evaporate and the ink will deteriorate. The composition ratio changes, which may cause ink failure to be ejected and impair printing ability. Therefore, in this embodiment, a cap 40 is attached to the cartridge 33, and the ink ejection port is covered by the cap 40 as necessary. As shown in the figure, the cap 40 is pivotally supported by a pin 41 on the side surface of the tip of the container 32, and is rotatable up and down. Cartridge 33
While the cap 40 is attached to the recorder and is performing a printing operation, the cap 40 is opened upward as shown by the solid line in FIG. 11 and held in a position where it does not interfere with printing. Also, cartridge 3
When storing the recorder with the recorder removed from the recorder, or when printing is not being performed even with the recorder attached, the cap 40 is rotated downward as shown by the imaginary line in FIG.
It fits into the ink ejection opening of the recording head main body 30. At this time, the rubber pad 43 supported by the leaf spring 42 inside the cap 40 comes into close contact with the ink discharge port to prevent the solvent in the ink from evaporating. By attaching the cap 40 in this way and covering the ink ejection port when not in use,
The physical properties of the ink are maintained constant, allowing for high-quality printing.

[0035]

[Effects of the Invention] As described above, according to the present invention, multicolor printing is possible by arranging a plurality of ink nozzles constituting a Kaiser type on-demand inkjet recording head in parallel on the same substrate. Despite this, the entire recording head can be made thin and compact. Furthermore, since the main parts of the recording head are formed centrally on the substrate, manufacturing becomes easier and costs can be reduced. Furthermore, by focusing on the physical properties of the ink and performing various treatments on the ink flow path and the edge of the substrate as necessary, it is possible to remove air bubbles in the ink and eliminate satellites, improving printing quality and ink ejection. It is possible to stabilize the Moreover, when the ink tank is integrated and the entire ink tank is made into a cartridge, handling and maintenance become easier, and usability can be improved. Due to the above effects, when the present invention is applied to an analog recorder,
The recorder itself can be made thinner and smaller, its cost can be reduced, and its reliability can be improved.

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view for explaining the structure of a first embodiment of the present invention.

FIG. 2 is a basic configuration diagram of a Kaiser type on-demand inkjet recording head to which the present invention is applied.

FIG. 3 is a sectional view showing a first embodiment of the present invention.

FIG. 4 is a perspective view showing a fourth embodiment of the present invention.

FIG. 5 is a perspective view showing a fifth embodiment of the present invention.

FIG. 6 is a sectional view showing a sixth embodiment of the present invention.

FIG. 7 is a sectional view showing a seventh embodiment of the present invention.

FIG. 8 is a partial sectional view showing an eighth embodiment of the present invention.

FIG. 9 is a longitudinal sectional view showing an eighth embodiment of the present invention.

FIG. 10 is an external view showing a ninth embodiment of the present invention.

FIG. 11 is an explanatory diagram of the operation of the ninth embodiment.

FIG. 12 is a side view of the ninth embodiment.

FIG. 13 is a sectional view showing a conventional technique.

FIG. 14 is an enlarged cross-sectional view of a main part of a conventional technique.

[Explanation of symbols]

9 Ink tanks 10, 13, 19, 21 Ink supply paths 11, 20
Ink pressure chambers 12, 22, 22a, 22b, 22c, 22d Ink nozzles 14, 23 Vibration plates 15, 24 Piezoelectric elements 16, 17 Head substrate 18 Ink reservoirs 25a, 25b, 25c, 25d, 25e Slits 26a, 26b, 26c , 26d, 26e groove 27,
28 Heater 30 Recording head body 31 Ink bag 32 Container 33 Cartridge 40 Cap 41 Pin 43 Rubber pad

Claims (8)

[Claims] 1. An inkjet recording head characterized in that a plurality of ink nozzles constituting a Kaiser type on-demand inkjet recording head are arranged in parallel on the same substrate. 2. The ink jet recording according to claim 1, wherein an ink flow path communicating with an ink nozzle is carved on the surface of the silicon substrate by dry plasma etching, and a glass plate serving as a diaphragm is electrostatically bonded to the upper surface of the substrate. head. 3. The ink jet recording head according to claim 1, wherein the surface of the ink flow path communicating with the ink nozzle is washed with alkali. 4. The ink jet recording head according to claim 1, wherein a water-repellent coating is formed on the end surface of the substrate around the ink discharge openings of the ink nozzles. 5. The ink jet recording head according to claim 1, wherein a cutout portion having a cross-sectional area larger than the cross-sectional area of the ink nozzle is formed between the ink ejection ports of adjacent ink nozzles. 6. The ink jet recording head according to claim 1, wherein a heater is arranged on the surface of the substrate where the ink flow path is located. 7. A cartridge according to claim 1, wherein a recording head body including an ink nozzle and a substrate and an ink tank for supplying ink are housed in the same container.
7. The inkjet recording head according to 4, 5 or 6. 8. The ink jet recording head according to claim 7, further comprising a cap rotatably supported on the cartridge and capable of covering the ink discharge ports of the ink nozzles by rotation.