JP2002154210A - Method of manufacturing ink jet recording head, ink jet recording head and ink jet recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eject a markedly small ink drop and to improve the arrival accuracy of the ink drop. SOLUTION: An inorganic material such as SiO2, TiO2 and ZrO2 is dissolved into a solvent including an alkoxide, methoxide, proxide, n-methylpropiden, or the like and a dissolution material of the solvent and an epoxy photosensitive resin is subjected to spin-coating on a metallic substrate 9 to be prebaked to form a first layer 10. An epoxy positive type photosensitive resin is applied on the first layer 10 to form a second layer 11. The exposing by ultraviolet rays is applied thereto by using a mask 22 that allows an exposing light to pass through only a region in a diameter of an ejection nozzle 3. The exposing by ultraviolet rays is further applied thereto by using a gradation mask 23 having a gradation section 25. Next, the exposed section is removed and a curing treatment is executed. Finally, the metallic substrate 9 is dissolved by diluted hydrochloric acid or the like to obtain an orifice plate 1 having the ejection nozzle 3 in which a straight line section 12 and a curve section 14 are formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing an ink jet recording head for recording an image by discharging ink onto a recording medium such as paper, an ink jet recording head, and an ink jet recording apparatus.

[0002]

2. Description of the Related Art One of the principles of the ink jet printing system is disclosed in U.S. Pat. No. 4,723,129, but it has been widely used as an on-demand system since 1985 as a printer product.

An ink jet recording head for discharging ink is disclosed in Japanese Patent Application Laid-Open Nos. 3-101944 and 6-84.
As disclosed in JP-A-47-47 or JP-A-9-183228, an orifice plate made of polyimide, polysulfone, nickel, stainless steel or the like is used. In an ink jet recording head using these materials, discharge ports are formed by a method such as laser processing, plating, or punching.

Polyimide has been used as a film or a plate because it can be formed only in a film state. However, the coefficient of thermal expansion of the polyimide is smaller than the coefficient of thermal expansion of a silicon plate by a degree that can be used by joining them. Because of this difference, it is processed by an excimer laser and used as an orifice plate in an ink jet recording head.

Polysulfone is tough, has heat resistance up to a considerably high temperature, can be used as a molding resin,
Further, since it is possible to perform excimer laser processing, it has been used as an orifice plate of an ink jet recording head or a structure of an orifice plate.

On the other hand, since nickel and stainless steel are metals, their abrasion resistance is good. However, because of its nature, microfabrication is difficult, so that it is only possible to form a discharge port having a relatively simple shape, and it has been mainly used as an orifice plate. Furthermore, since the thermal expansion coefficient is higher than that of silicon or ceramics, short inkjet printheads can be formed, but with long inkjet printheads, the effects of deformation due to thermal expansion cannot be ignored, making it difficult to use. Have. As an example of the prior art, Japanese Patent Application Laid-Open No. 8-58094 discloses an ink jet recording head using an orifice plate formed by plating a nickel orifice plate and using a gold plating so as not to be corroded by ink.

[0007] These orifice plates are 10 pl
There was no particular problem if the image was of a level at which ink jet droplets were ejected. The image quality of this level is slightly coarse, and the image quality is slightly coarse. If the eyes are away from the printed image by about 30 cm, the particles of the ink-jet droplet are almost completely printed (one dot printed).
Was of an unidentifiable level.

However, in order to print a high-quality photographic image, the size of ink-jet droplets has to be reduced to 3 pl or 2 pl or less. .

This is because the volume of a droplet is three times the radius of the droplet.
This is because, in order to be proportional to the power, in order to reduce the size of the print particles (print dots) in the ink jet by half, the volume must be reduced to the 1/3 power.

With the naked eye of a human, dots having a diameter of about 45 to 48 μm or less cannot be recognized. on the other hand,
In the case of about 8 to 10 pl of ink-jet droplets, the size of ink-jet print particles is about 50 to 60 μm in diameter. Therefore, when the distance is set to about 4 pl, the distance becomes smaller than the recognition range of human eyes.

However, since the color tone is generally formed by a combination of Y (yellow), M (magenta) and C (cyan), one dot is formed by a combination of these ink jet print particles. Therefore, it is necessary to make the size of the dot having a diameter of about 45 to 48 μm or less by combining the dots of this color.
Basically, since the dots are arranged so as to overlap by about 30% or more, the size of one dot is 30 μm in diameter.
If it is less than m, it will be substantially less than the human visual recognition range, and a smooth, high-quality photographic image without graininess will be obtained. Generally, particles in silver halide photography are said to be 3000 dpi,
The diameter is about 10 μm. Therefore, even if this level is not reached, the size of one dot can be reduced to 30 μm in diameter.
It should be less than the degree.

However, the size of one dot is 30 μm in diameter.
m, the volume of the inkjet droplet is 2 to 2.
3 pl. As described above, it is very difficult to eject ultra-fine droplets by inkjet. The reason is that since the volume of the droplet is very small, it is difficult to make the diameter of the discharge port of the ink jet orifice plate 10 μm or less, and to form a discharge port having a shape in which a curve and a straight line are smoothly continued. This is because it is difficult to improve the landing accuracy in the ink jet discharge.

In order to improve the landing accuracy, Japanese Patent Laid-Open No.
In Japanese Patent Application Laid-Open No. H.-997, as shown in FIG. 11, the straight portion 214 of the ejection port 203 of the ink jet is perpendicular to the recording medium, and the ratio of the length of the straight portion 214 is set to the ejection port 20.
An example is disclosed in which the ejection and flying direction of ink is changed as 20 to 80% of the diameter of No. 3. According to this publication, the formation of the straight portion 214 reduces the flow resistance in the ink ejection direction, improves the ejection speed of the ink flowing through the straight portion 214, and is faster than the ink flowing through the curved portion 213. It describes that the vector in the ejection direction of the ink is bent at the exit, and the ejection direction can be controlled.

[0014]

However, in Japanese Patent Application Laid-Open No. H11-997, it is possible to vary the size of the ink droplet by controlling the heating time of the ink-jet, thereby reducing the size of the ink droplet to about 30 pl or 8 pl. There is a description that the droplet can be controlled to be discharged, but there is no description about a method of forming the shape of the discharge port 203. Also,
In this case, the straight portion 212 and the curved portion 214 are connected by forming a bending point 213 having an angle. It has been confirmed that the presence of the inflection point 213 causes stagnation or turbulence of the flow during the ejection of the ink jet, and that good ejection is not formed. More specifically, the curved portion 214 and the straight portion 21
There is no description about the discharge port 203 corresponding to a discharge amount of about 3 pl or 2 pl in which 3 smoothly continues, and the description of the technique of the forming method.

That is, as a problem of the prior art, when the number of ink droplets of the ink jet becomes 2 to 3 pl, it is necessary to form the ejection port with a diameter of 10 μm or less with less variation in each ejection port. There is a point that it is quite difficult to perform such fine processing.

Further, when the size of the ink-jet droplet becomes 2-3 pl, the flying speed of the droplet becomes low, and the flying of the ink-jet droplet is affected by the resistance and flow of the air in the flying space. The direction may fluctuate, the landing accuracy on a medium such as paper may shift, and the image quality may deteriorate. In addition, when the size of the ejection port is reduced, the positional accuracy between the center of the inkjet ejection function unit and the center of the ejection port is likely to shift, which may cause a deviation in the direction of inkjet ejection.

In order to eliminate the deviation in the direction of the ink jet discharge, the shape of the discharge port formed in the orifice plate is as disclosed in Japanese Patent Application Laid-Open No. 8-58094.
Some are formed to have a gentle curved cross section. This is one method of stabilizing the flight direction of droplets in inkjet discharge, and is widely adopted as a nodal horn structure in a mechanism using longitudinal wave vibration propagation. The nodal horn structure is used especially for horns of ultrasonic welding machines and cones of speakers.

However, in an orifice plate having a thickness of about 10 to 30 μm, 10 μm
It is almost impossible to form an orifice having a cylindrical shape with a diameter of about m and a cross section widened so as to draw a quadratic curve. That is, in the conventional plating and punching, a cylindrical discharge port having a linear cross section can be formed only about 1/10 of the thickness of the orifice plate.
It is firstly impossible to form the following discharge ports. Further, in laser processing, the shape becomes too linear, and a nodal portion cannot be formed.

Accordingly, the present invention provides a method of manufacturing an ink jet recording head capable of discharging very small ink droplets and improving the landing accuracy of the ink droplets by stabilizing the discharge direction. It is an object to provide a head and an ink jet recording apparatus.

[0020]

The inventors have found the following means in order to solve such problems of the prior art.

The discharge port is formed by forming a cylindrical orifice by means of a photolithography process such as pre-baking and photosensitive exposure after coating a polyimide or epoxy resin film with a solvent resin. It was decided to. In addition, at the time of exposure to light, the transmittance of the exposure light is not uniform, and the transmittance is gradually changed. The exposure and exposure are performed using a so-called gradation formed mask, and the ink inlet side is processed into a gentle nodal shape. We decided to adopt the method. If processing is performed using a mask on which gradation is formed as described above, it is possible to form the ink-jet ink inlet side in a nodal shape even at a discharge port having a diameter of about 10 μm or less. Further, an ink jet ejection orifice can be formed up to a diameter of about 1 μm.

Thereafter, the orifice plate having a discharge port in the form of a nodal horn can be formed by etching the holding substrate such as a metal with a solution such as an acid.

The feature of the discharge port formed by this method is that its cross section can be almost formed into an arbitrary curve depending on the shape of the gradation pattern. It is also possible to form this curved portion continuously with a substantially straight cylindrical portion having a depth of about 1/10 to 1/3 of the depth of the ink jet ejection orifice.

Since the discharge port formed by such a method can continuously form a nodal-shaped curved portion and a linear portion, the traveling direction of the plastic wave of ink-jet discharge at the time of ink discharge is continuous. There is a feature that the traveling direction of the plastic wave is reliably fixed by having the straight portion.

In particular, when the center of the plastic injection wave causing the ink jet discharge is displaced from the center of the discharge port, the discharge direction can be stabilized by the following mechanism.

In other words, the foaming phenomenon of bubbles that induces ink-jet ejection is such that, when the center of foaming is displaced, the bubble expands around this displaced position, and the instantaneous expansion accelerates the ink, causing the ink to accelerate. Ink is ejected when the wall or obstacle is present in the ejection direction of the ink jet, and the resistance is inversely proportional to the distance of the obstacle. If the resistance is large, the expansion of the bubble in that direction is impeded, and the expansion of the bubble in another direction is caused.
Next, the ink that has begun to move due to the expansion of the bubbles is now subjected to viscous drag from the obstacle. The magnitude of this viscous drag is inversely proportional to the distance between the wall and an obstacle.

Accordingly, the ink near the interface between the bubble and the ink continues to receive a force from a wall or an obstacle that is inversely proportional to the square of the distance. If the wall surface is curved, rejection from the wall experiences a resistance at a particular point that is inversely proportional to a higher-order function of square or higher. Therefore, the movement of the ink is defined by the instantaneous explosive foaming force in foaming and the positional and temporal change of the drag from the wall.

Therefore, the expansion direction of the bubbles is converged as a quadratic curve as a function of time toward the center of the discharge port having the lowest resistance of the discharge liquid chamber. Is directed to the center of the discharge port.
The plastic wave of the ink jet heading toward the center of the discharge port converges the vector in the linear direction if the linear portion of the wall surface is long near the outlet of the discharge port, and coincides with the ink discharge direction. In this way, even if the center of the foaming foam is shifted from the center of the liquid chamber for some reason, the flow of the ink jet is completely converged in one direction near the outlet.

Therefore, for example, in the case of a 2 pl ink droplet, if the diameter of the discharge port is 8 μm, it becomes a liquid column having a length of about 40 μm, and the vectors can be aligned.
However, in the case of a discharge port having a diameter of 20 μm, the length is about 6.5 μm, which is almost a flat columnar state, and the vectors cannot be aligned. Thus, in order to stabilize the ejection direction of the ink jet, it is desired that the length of the ejected liquid column is twice or more the length of the bottom surface of the liquid column.

By the way, in performing the above-mentioned method for forming an orifice plate, a new problem was confirmed. These are the eight issues listed below. The point where it is difficult to form a straight line part by etching the orifice. When the substrate plate of the orifice plate is removed by etching, the orifice plate warps in a curl shape due to residual stress, making accurate bonding difficult. When a silicon substrate is used as a substrate, etching takes time and man-hours increase.In addition, the substrate is expensive and economically inefficient.Since the orifice plate is extremely thin, handling is very inconvenient and easy. Points that are difficult to handle because they are torn or cracked. Bonding strength at the time of bonding with the inkjet discharge means is weak and easy to peel off. External electrical contacts of the inkjet discharge means are difficult to remove. The straight line at the exit of the orifice hole is photolithography. In this case, a slight but oblique taper is formed. Strictly speaking, the photosensitive resin layer forming the orifice is not parallel to the direction of the ink jet ejection, or is partially parallel and partially tapered. Even when solidification is performed by baking, the resin is basically a resin, and the inorganic component contained in the paper powder is easily damaged, which is the above-mentioned eight problems.

Means and methods for solving these problems will be described sequentially.

In order to form a linear portion, exposure is performed using a mask on which no gradation is formed, and then exposure is performed using a mask on which a gradation is formed, and the exposure time and exposure illuminance are changed. Thus, a straight line portion and a curved portion can be formed.

The gradation mask can form a dot having a wavelength equal to or less than the wavelength of the exposure light beam, thereby obtaining a gentle exposure attenuation curve and obtaining a curved state of the cross section of the orifice.

The cause of the orifice plate warpage is as follows.
Because the thickness of the applied photosensitive resin is as large as 10 μm or more, the degree of scattering and removal of the solvent is different between the vicinity of the substrate surface and the surface layer, and the coefficient of thermal expansion between the substrate and the photosensitive resin is large. Has been confirmed to be the main cause. Thus, the application of the photosensitive resin is not performed at a time of 10 μm or more, but is performed by dividing the photosensitive resin into a thickness of about 5 μm a plurality of times.

The coating was performed about 5 μm, pre-baked, and then the coating and pre-baking were performed, so that the solvent was scattered in a plurality of times. Further, a photosensitive resin was coated on the silicon substrate, subjected to pre-bake exposure, development, curing and the like to form an orifice plate. After dissolving and removing the substrate, slight warping still occurred. This is because the curing temperature is as high as 180 ° C. or more, and molecular bonding of the photosensitive resin is finally formed at this stage. However, the surface layer can be thermally shrunk almost freely at the stage of returning to room temperature. On the other hand, the portion near the substrate cannot be freely contracted because it is almost temporarily bonded to the silicon substrate. Therefore, means for forming a coated substrate with metals having substantially the same thermal expansion coefficient as that of the photosensitive resin is employed. As a result, the warp of the orifice plate was considerably reduced in iron, nickel, copper, and the like, and the plate became almost flat.

The silicon substrate does not dissolve well because it forms a passivation film in acid. The silicon substrate is HF
It dissolves in (hydrofluoric acid) but damages the photosensitive resin film. Furthermore, although it dissolves in alkali, it requires a considerable dissolution time, and at 60 ° C., about 5 to 10 mass%
Approximately 40 hours are required even with a strong alkaline solution of OH. Therefore, a metal that is easily dissolved in an acid such as iron, copper nickel, or tin is used as a substrate, and the metal substrate is dissolved. As a result, it was possible to dissolve and remove the substrate in about 4 hours at around room temperature using diluted hydrochloric acid, diluted sulfuric acid, or a mixed acid with these organic acids. Also, while silicon substrates are expensive, these general metal plates are inexpensive and economically advantageous.

The thickness of the orifice plate is 10 μm
Approximately, since it is only about 30 μm thick even when thick, it is easy to bend, and because it is easy to tear, it is difficult to handle, and it is necessary to perform good alignment even at the time of joining with the inkjet discharge means, This alignment is also difficult.

Therefore, in dissolving and removing the substrate, a dissolution inhibiting film is partially formed, and the substrate is left in a lattice, so that the remaining substrate is used as a holding substrate for handling the orifice plate. As a result, the substrate having high rigidity is handled while being held by suction or suction, so that it is possible to perform good bonding with the inkjet discharging means.
In particular, since nickel and iron plates react to magnetism, they can be magnetically attracted and conveyed, and handling is extremely simple. The substrate may be any alloy of nickel or iron as long as it is a ferromagnetic material and can be magnetically attracted and transported.

Since the orifice plate is formed by spin coating, the portion excluding the orifice is flat, flat and extremely mirror-finished. Even if the device in this state is bonded to the ink-jet discharging means via an adhesive having a thickness of about 1 to 2 μm, a certain degree of bonding strength can be obtained, but it may be partially removed. In such a case, the peeled portion slightly rises at the moment of the ink jet discharge, which hinders the ink jet discharge. Therefore, a slight unevenness of 0.3 to 0.5 μm or less is formed on the surface of the spin coat. As a result, the adhesive penetrates into the uneven portion to increase the bonding surface, and it is possible to improve the bonding strength by the anchor effect of forming a hook.

In this method, after the prebaking, after the exposure, or after the development, the photosensitive resin is not yet completely bonded and cured, and the unevenness of about 0.3 to 0.5 μm or less is required. A metal roll was pressed lightly to form fine irregularities. However, it was easily formed after pre-baking and exposure. As another method, irregularities can be formed by forming an infinite number of circles or polygons of about 2 to 3 μm on a mask and restricting exposure. Alternatively, a powder having a particle diameter of about 0.3 μm or less of the same material as the photosensitive resin is dissolved in a solvent by about 1%, and this is spray-coated on the pre-baked film.
Alternatively, it is also possible to perform spin coat drying.
This process may be performed after exposure. However, it is not preferable to carry out after development.

In order to drive the ink-jet discharge means, it is necessary to electrically connect a means for supplying a drive signal or power to the ink-jet discharge means. However, the joining area is fixed to a certain defined surface of the inkjet discharge means. This is because the discharge means is formed by an electric circuit formed on a silicon substrate, a heating resistor and its protective film, so that it is necessary to cut four surfaces from one large silicon wafer to use it. It will be used by cutting out. In such a case, since the electrical contacts are not formed penetrating the inside of the silicon wafer in the vertical direction, the electrical bonding region has to be formed on the surface on which the inkjet discharging means is formed. Therefore, in order to form an electric signal contact, an opening is provided in the orifice plate to form an electric signal contact.

In a method of manufacturing an orifice plate by photoetching, scattering / absorption through internal passage is unavoidable for the arrival of ultraviolet light by exposure, so strictly speaking, the etched cross section cannot be vertical, It has a taper of about 0.5 to 3 degrees. In addition, slight dispersion due to dispersion and fluctuation of the resin resulted in a part of the dispersion.
Non-uniformity such as tapering of about 5 degrees and other parts having a taper of 1-3 degrees of kneading occurs. However, it has been found that when photoetching is performed in a state where an inorganic substance is uniformly dissolved in the form of an alkoxide or the like in a photosensitive resin, the etched cross section becomes vertical.
Accordingly, inorganic substances such as SiO ₂ , TiO ₂ , and ZrO ₂ are obtained in the form of methoxide, alkoxide, and proxide,
This was dissolved in n-methylpropidone to form a solution with the photosensitive resin, and spin-coated to form a photosensitive resin layer,
Exposure / development made it possible to produce an orifice plate whose cross section was straight and perpendicular to the ink jet ejection direction.

The portion forming the curved portion is formed of a photosensitive resin to which no inorganic substance is added, and the portion forming the linear portion is a two-layer orifice plate having a photosensitive resin layer to which the inorganic material is added. The problem was solved.

Of course, an ink-repellent layer may be formed on the exit surface of the orifice plate to form a three-layer structure. Further, a photosensitive resin layer or a photosensitive resin containing an inorganic substance may be used. May be configured as two or more layers, and may be configured as three or more layers.

In order to improve abrasion resistance, it is basically possible to add an inorganic substance having high hardness to the inside of the photosensitive resin layer. However, it is impossible to perform a uniform dispersion simply by adding an inorganic substance. Therefore, it was decided to perform dispersion addition at the molecular level used for the above problem.

In this method, an inorganic substance is dissolved in a solvent in the form of methoxide, alkoxide, or proxide, and the resulting solution is mixed with a photosensitive resin. The solution is applied by a method such as spin coating or spray coating, and dried / condensed. By doing so, it becomes possible to form an orifice plate in which inorganic substances are uniformly dispersed at the molecular level, and thereafter, if the temperature is increased or other processing is performed to remove the organic portion, and the inorganic substances are precipitated, resistance to paper dust and the like is obtained. It is also possible to improve the abrasion.

When the dimensions are slightly displaced due to drying / condensation, etc., stabilize the process and take a method of manufacturing an orifice plate in consideration of the shrinkage dimension in advance, or make all dimensions uniform. For example, there is a method of joining, pasting, or performing alignment within the above temperature conditions.

The manufacturing method of the ink jet recording head of the present invention, the ink jet recording head, and the ink jet recording apparatus in consideration of the above points will be described below.

That is, according to the method of manufacturing an ink jet recording head of the present invention, there is provided an ink jet recording element having a liquid flow path provided with an energy generating element for generating energy used for discharging ink, and the ink jet recording head. An orifice plate joined to an element and having a plurality of orifices formed at portions corresponding to the respective liquid flow paths and communicating with the respective liquid flow paths, the method forms the orifice plate. Forming at least one photosensitive resin layer made of the photosensitive resin on a metal substrate having a coefficient of thermal expansion substantially equal to the coefficient of thermal expansion of the photosensitive resin, and a portion corresponding to a minimum diameter of each orifice And the transmittance of the exposure light between the portion corresponding to the maximum diameter of each orifice is gradually changing. Exposing the photosensitive resin layer to light using a gradation mask having such a transmittance distribution, and forming each of the orifices such that a part of a side cross section of the orifice becomes a curve. I do.

The method for manufacturing an ink jet recording head according to the present invention as described above includes a step of forming an orifice using a gradation mask having a transmittance distribution such that a part of the side cross section of the orifice is curved. That is,
For example, in the case of a positive gradation mask, the transmittance of the exposure light gradually decreases from a portion corresponding to the minimum diameter of the orifice to a portion corresponding to the maximum diameter of the orifice, so that the photosensitive resin is Since the exposure amount in the thickness direction decreases from the minimum diameter portion of the orifice toward the maximum diameter portion of the orifice, a part of the side cross section of the orifice is formed in a curved shape. By processing using such an exposure process, even if the diameter of the orifice on the outlet side of the ink is about 10 μm or less, the inlet side is made continuous with the traveling direction of the plastic wave of the inkjet discharge at the time of ink discharge. It is possible to process into a nodal shape with a gentle curve that can be targeted.

Further, according to the method of manufacturing an ink jet recording head of the present invention, a first photosensitive resin layer made of a photosensitive resin is formed on a metal substrate having a thermal expansion coefficient substantially equal to that of the photosensitive resin layer. And a layer forming step of laminating at least one photosensitive resin layer on the first photosensitive resin layer. In this case, at the stage of returning to the room temperature from the curing temperature at the time of curing performed to finally form the molecular bond of the photosensitive resin, the release surface side of the photosensitive resin layer not in contact with the metal substrate, Since the degree of thermal shrinkage of the first photosensitive resin layer temporarily bonded to the metal substrate and that of the temporary bonding surface side can be made substantially equal, curl-like warpage of the formed orifice plate is reduced to substantially reduce A flat orifice plate can be formed.

Further, the method may include a step of exposing the photosensitive resin layer by using a mask having no transmittance distribution so that a part of the side cross section becomes linear to form each orifice. . In this case, since a linear portion for matching the vector of the plastic wave of the ink jet heading toward the center of the ejection port with the ejection direction of the ink can be formed, the landing accuracy of the ink can be further improved.

Further, a step of forming a first photosensitive resin layer into an ink-repellent layer by containing a material exhibiting ink-repellent property, and laminating at least two photosensitive resin layers on the ink-repellent layer. And a step of forming. In this case, by using the ink-repellent first photosensitive resin layer as the surface on the ink jet discharge side, in the case of performing continuous ink jet discharge, fluctuations and variations in the ink jet discharge direction due to adhesion of ink mist are avoided. It is possible to do.

Further, the method may include a step of forming a first photosensitive resin layer with a mixed solution of a photosensitive resin and a solvent in which an inorganic substance is dissolved and contained in the form of alkoxide, methoxide or proxide. In this case, at the time of exposure, since the inorganic substance is added in a form dissolved in an organic solvent, the dispersion at the molecular level occurs, and the scattering and absorption of exposure light in the first photosensitive resin layer are suppressed. Become. For this reason, the straightness of light is exhibited in the transmission of the exposure light beam, the sharpness of the development in photolithography is sharpened, and the cross section of the inkjet discharge orifice is parallel to the direction of travel of the exposure light beam. Can be processed into a straight shape.

In the method of manufacturing an ink jet recording head according to the present invention, a metal substrate having magnetic properties may be used as the metal substrate, or a metal substrate made of iron or nickel may be used. In this case, since a general metal such as copper or nickel is used for the metal substrate used as the holding substrate, it is very economically advantageous from the viewpoint of speeding up the removal of the holding substrate and the cost of the substrate itself, and improving productivity. Will also be higher.

Further, as the metal substrate, a metal that can be dissolved and removed in a shorter time than the time required for dissolving and removing silicon may be used, or the metal substrate made of zinc or tin may be used. You may.

Further, the method may include a step of forming the first photosensitive resin layer on a mirror-finished surface of a metal substrate.

Further, the method may include a step of forming the first photosensitive resin layer on a surface of the metal substrate having a maximum height Rmax of 0.5 μm or less.

Further, the method may include a step of forming the holding portion of the orifice plate by partially dissolving and removing the metal substrate. In this case, for example, by leaving the metal substrate in a lattice shape, a substrate having high rigidity is held and handled by suction or suction, and good bonding with the inkjet recording element can be performed. In particular, since nickel and iron plates react to magnetism, they can be transported by magnetic attraction.
Handling becomes very simple.

When the photosensitive resin layers are sequentially laminated in the layer forming step, the next photosensitive resin layer is formed after the step of prebaking the photosensitive resin layer and the step of drying the photosensitive resin layer are completed. It may include a step of laminating.

A plurality of irregularities having a maximum height Rmax of 1 μm or less are formed on the surface of the second photosensitive resin layer formed last, which is to be bonded to the ink jet recording element, of each photosensitive resin layer. May be included. In this case, the adhesive penetrates into the uneven portion, increasing the bonding surface, and the anchor effect of forming a hook portion,
It has become possible to improve the bonding strength.

Further, the method of manufacturing an ink jet recording head of the present invention includes a cutting step of cutting a plurality of orifice plates manufactured together as individual orifice plates before joining to an ink jet recording element. Alternatively, it may include a cutting step of cutting a plurality of orifice plates manufactured together as individual orifice plates after joining to the ink jet recording element. It may be used.

The ink jet recording head of the present invention has an ink jet recording element having a liquid flow path provided with an energy generating element for generating energy used for discharging ink, and is joined to the ink jet recording element. An ink jet recording head having an orifice plate formed with a plurality of orifices communicating with the respective liquid flow paths at portions corresponding to the respective liquid flow paths, manufactured by the method for manufacturing an ink jet recording head of the present invention. It is characterized by having been done.

As described above, since the ink jet recording head of the present invention is manufactured by the method of manufacturing an ink jet recording head of the present invention, the ink inlet side of the orifice has a nodal shape with a gentle curve, and the diameter of the outlet side is smaller. The orifice has a diameter of about 10 μm or less, and further has a diameter of about 1 μm. For this reason, the traveling direction of the plastic wave of the ink jet discharge at the time of ink discharge becomes continuous. In addition, when the orifice has a straight portion in addition to the curved portion, the traveling direction of the plastic wave is reliably stabilized, and the flying direction of the droplet can be stabilized.

The diameter of the orifice on the inlet side where the ink flows in is 1.times. The diameter on the outlet side where the ink is discharged.
It may be 5 times or more, the opening area of the orifice on the inlet side where the ink flows in may be 2.25 times or more of the opening area on the outlet side where the ink is ejected, The diameter on the outlet side may be 10 μm or less, the radius of curvature on the inlet side may be 10 μm or less, and the thickness of the orifice plate may be 20 μm or less.

The photosensitive resin may be an epoxy resin or a polyimide resin.

The orifice plate may have an opening for supplying an electric signal to the energy generating element.

The length of the straight portion having a straight side cross section may be 1/10 to 1/2 of the thickness of the orifice plate. , 5 to 80% by mass of an inorganic substance, and the area of a plane perpendicular to the ink ejection direction in the linear portion may be constant.

The ink-repellent surface of the ink-repellent layer may be the surface of the orifice plate on the outlet side where ink is ejected.

The energy generating element may be an electrothermal converter for generating thermal energy for discharging ink.
The ink may be ejected from an ejection port formed of an orifice using the film boiling generated in the ink by the heat energy applied by the electrothermal transducer.

The ink jet recording apparatus of the present invention holds a conveying means for conveying a recording medium, an ink jet recording head of the present invention for discharging ink and performing recording on the recording medium, and And holding means for reciprocating in a direction substantially perpendicular to the transport direction.

As described above, the ink jet recording apparatus of the present invention performs recording by the ink jet recording head manufactured by the method of manufacturing an ink jet recording head of the present invention. Therefore, very small ink droplets are stably ejected, and the image quality of a recorded image can be improved.

[0073]

FIG. 1A is a perspective view of an ink jet recording head according to an embodiment of the present invention, and FIG.
2 shows an exploded perspective view, and FIG. 2 shows a plan view of an ink jet recording element.

The ink jet recording head 300 includes a recording element substrate 70 on which the electrothermal transducer 100 is provided, and an ink flow path forming member 80 on which an ink flow path 81 is formed.
And the orifice plate 1 in which the discharge port 3 is formed.

The electrothermal transducer 100 of the recording element substrate 70
Are provided so as to correspond to the respective ink flow paths 81 and face the respective ejection ports 3. An electrothermal transducer 100 formed on the recording element substrate 70;
And an electric wiring (not shown), such as Al, for supplying electric power to the device are formed by a film forming technique.

In the ink flow path 81, after a bonding strength assisting process is performed on the recording element substrate 70 with a silane coupling agent or the like, an epoxy photosensitive agent is spin-coated, and then an epoxy photosensitive adhesive is applied. Spin coating was performed, followed by pre-baking, exposure to ultraviolet light using a mask having a predetermined ink flow path pattern, development processing with methyl isobutyl ketone, and further curing processing.

The cross-sectional shape of the flow path 25 formed in the orifice plate 1 and communicating with the discharge port 3 has a nodal shape with a curved line narrowing toward a straight line portion 12 described later, with the inlet side 18 into which the ink flows is opened. And a straight line portion 12 which is smoothly connected to the curved line portion 14 and has a straight tapered shape narrowed toward an outlet side 18 where ink is ejected.

The orifice plate 1 of the present embodiment
Has an opening 20 for electrical signal connection other than the discharge port 3. This is to address the following problem.

In order to drive the ink jet recording head 300, it is necessary to electrically connect a means for supplying a driving signal or electric power from the outside to the ink jet recording head 300. However, the bonding area is fixed to a certain surface of the printing element substrate 70 constituting the ink jet printing head 300. This is because the recording element substrate 70 is formed by an electric circuit formed on a silicon substrate, the electrothermal conversion element 100 and its protective film,
To use this, you need 4 large silicon wafers.
It will be used by cutting and cutting out the surface. In this case, since the electrical contacts are not formed penetrating the inside of the silicon wafer in the vertical direction, the electrical bonding region has to be formed on the surface of the recording element substrate 70. Therefore, in order to form the electrode 20, the opening 21 is provided in the orifice plate 1 and the electrode 21 is formed.

The method of forming the orifice plate 1 will be described later.

The orifice plate 1 was positioned with respect to the ink jet recording element 200 formed as described above, and the orifice plate 1 was hot-press bonded to the ink jet recording element 200. At this time, an epoxy polymer was used as the adhesive.

The bonding between the ink jet recording element 200 and the orifice plate 1 may be performed before or after the plurality of orifice plates 1 manufactured collectively as individual orifice plates 1 are separated. It may be performed later.

In the ink jet recording head 300 having the above-described structure, the ink supplied through the ink flow path 81 is heated by supplying electric power to the electrothermal conversion element 100 through electric wiring. This causes bubbles to be generated in the ink to cause the ink to be ejected from the ejection openings 3 to perform recording on a recording medium such as recording paper. When the ink is ejected, a configuration may be adopted in which bubbles formed on the electrothermal transducer 100 are communicated with the atmosphere via the ejection port 3.

Next, a method for forming an orifice plate will be described with reference to FIG. 3 showing a procedure for forming an orifice plate and FIG. 4 showing a flowchart.

In FIG. 3, the thicknesses of the first layer 10 and the second layer 11 are t ₁ and t ₂ , and the total thickness of the first layer 10 and the second layer 11 is t ₃ The thickness of the formed orifice plate 1 is t ₄ , and the outlet side 19 of the discharge port 3
Is φ ₁ , the diameter of the inlet side 18 is φ ₂ , and the length of the straight portion 12 is L.

First, as shown in FIG. 3A, iron, copper,
On a metal substrate 9 such as nickel or tin, an epoxy-based positive photosensitive resin from which a region irradiated with exposure light is removed is spin-coated (step 51) and prebaked to form a first layer. 10 are formed (step 52).

Next, as shown in FIG. 3B, an epoxy-based positive photosensitive resin is again spin-coated on the first layer 10 (step 53), and prebaked to form a second layer. The layer 11 is formed (Step 54). Note that the thermal expansion coefficients of the first layer 10 and the second layer 11 and the metal substrate 9
Is almost the same as the coefficient of thermal expansion.

Next, as shown in FIG.
UV exposure is performed using the mask 22 that transmits the exposure light only within the area having the diameter of (step 55).

Next, as shown in FIG.
Further, ultraviolet exposure is performed by the gradation mask 23 having a predetermined gradation portion 25 around the mask having a diameter of (step 56).

In the case of a positive photosensitive resin, as shown in FIG. 5A, the gradation portion 25 of the gradation mask 23 has a transmittance of exposure light at an orifice outlet diameter corresponding portion 26 corresponding to the minimum diameter of the orifice. And the transmittance gradually decreases toward the portion corresponding to the maximum diameter of the orifice.In other words, the exposure amount in the thickness direction of the photosensitive resin changes from the minimum diameter portion of the orifice to the maximum diameter portion of the orifice. In the case of a negative photosensitive resin, the gradation portion 25 has a minimum diameter of the orifice, as shown in FIG. 5B. In the orifice outlet diameter corresponding portion 26 corresponding to the orifice, the exposure light is not transmitted, and the transmittance gradually increases toward the portion corresponding to the maximum diameter of the orifice. Gradation mask 23 with the Gradient is used.

As shown in FIG. 6, which is a schematic plan view of the gradation mask 23, the gradation portion 25 around the orifice outlet diameter corresponding portion 26 has a small transmission of a diameter of 1 μmφ or less on the exposure surface (photolithography processed surface). A plurality of portions 27 are formed. Since the minute transmitting portion 27 is denser as it approaches the orifice outlet diameter corresponding portion 26, for example, in the case of a positive type, the gradation portion 25 is configured such that the transmittance of the exposure light increases as it approaches the orifice outlet diameter corresponding portion 26. A light transmittance distribution.

The gradation mask 26 forms a dot having a wavelength equal to or smaller than the wavelength of the exposure light beam, thereby obtaining a gentle exposure decay curve and processing the cross section of the orifice into a nodal shape having a gentle curve.

As described above, the linear portion 12 is formed by performing exposure with the mask 22 on which no gradation is formed, and the exposure is performed with the gradation mask 23 on which gradation is formed. Is changed to form the curved portion 14.

In the above-described process, the first layer 10 and the second layer 11
After that, exposure is performed by the mask 22 in Step 55, and then exposure is performed by the gradation mask 23 in Step 56. However, depending on the diameter of the discharge port 3 to be opened, in step 52, FIG.
7B, after the first layer 10 is pre-baked, as shown in FIG. 7B, exposure is performed by the mask 22 that transmits the exposure light only in the area of the diameter of the discharge port 3 in step 55. After forming the first exposed portion 15 and performing after-baking, as shown in FIG.
At 54, the second layer 11 is formed.
As shown in (d), the second exposure unit 16 may be formed by performing exposure with the gradation mask 23.

Next, the exposed portion is removed by a well-known method (step 57), so that the discharge port 3 is opened on the metal substrate 9 as shown in FIG. 3 (e) or FIG. 7 (e). The orifice plate 1 of this state is formed, and the orifice plate 1 in this state is put into a post-baking device to perform a hardening process (step 58).

Next, the metal substrate 9 is dissolved with dilute hydrochloric acid, dilute sulfuric acid, or a mixture of these organic acids (step 59), so that an orifice plate as shown in FIG. 3 (f) or FIG. Get 1. The metal substrate 9
In dissolving and removing the metal substrate 9, the metal substrate 9 may be used as a holding substrate for handling the orifice plate 1 by partially forming a dissolution inhibiting film and leaving the metal substrate 9 in a lattice shape.

The first layer 10 and the second layer 11
May be formed using a polyimide photosensitive resin. At this time, without tapering the straight portion 12,
If a straight shape is desired, before step 51 in the flowchart shown in FIG. 4, as shown in the flowchart of FIG. 9, as step 50, SiO ₂ , TiO ₂ ,
An inorganic substance such as ZrO ₂ is dissolved in a solvent such as n-methylpropidone such as alkoxide, methoxide and proxide to prepare a solution with the photosensitive resin.
For spin coating on the metal substrate 9.
The inorganic substance may be any inorganic substance soluble in an organic solvent in the form of ethoxide, methoxide, proxide or the like, or may be a mixed composite form thereof. However, it is desirable to avoid those that adversely affect the ink jet ink. As described above, the inorganic substance is applied to the first layer 1.
When the first layer 10 is exposed to light, scattering and absorption of ultraviolet rays in the first layer 10 are suppressed, and the linear portion 12 is perpendicular to the ink ejection direction. It can be processed into a straight shape with a constant surface area.

The content of the inorganic substance in the layer where the linear portions 12 are formed may be 5 to 80% by mass.

In order to make the surface 5 of the first layer 10 ink-repellent, an ink-repellent layer is formed on the metal substrate 9 and then the first layer 10 is formed. Is also good. This ink-repellent layer may be formed by suspending and mixing, for example, polytetrafluoroethylene powder in a photosensitive resin.

Further, in order to improve the abrasion resistance of the first layer 10 or the ink repellent layer, for example, tetraethoxytitanium is dissolved in n-methylpyrrolidone, and Teflon (registered trademark) particles are added to this solution with a fatty acid. Suspended with a surfactant, mixed with a solution of a photosensitive resin,
To form the layer 10 or the ink-repellent layer. In this case, if the above-mentioned mixed solution is applied by a method such as spin coating or spray coating and dried / condensed, the orifice plate 1 in which inorganic substances are uniformly dispersed at the molecular level can be formed. If the organic portion is removed by raising or other treatment to precipitate an inorganic substance, it is possible to improve the abrasion resistance against paper dust and the like.

Further, on the bonding surface 7 of the second layer 11, which is a surface bonded to the ink jet recording element 200 with an adhesive, slight irregularities are formed in order to increase the bonding area. Is also good.

Further, a mixed composite form thereof may be used. However, it is desirable to avoid those that adversely affect the ink jet ink.

In this embodiment, an epoxy resin or a polyimide resin is used as the photosensitive resin. However, the present invention is not limited to this, and any photosensitive resin suitable for the orifice plate 1 may be used. Good. In particular, anything that satisfies high strength, toughness, flexibility, abrasion resistance, chemical stability, heat resistance, workability, dimensional stability, and the like, and can form an orifice plate by the method of the present invention. Good thing.

In this embodiment, ultraviolet light is used for exposure. However, visible light, soft X-ray, electron beam, or laser beam may be used as long as photolithography can be performed. .

Further, the diameter φ ₂ of the inlet side 18 of the discharge port 3 may be 1.5 times or more larger than the diameter φ ₁ of the outlet side 19, and the sectional area of the inlet side 18 of the discharge port 3 may be smaller than the outlet side. It may be 2.25 times or more than the cross-sectional area of 19.

Further, the diameter of the outlet side 19 is 10 μm or less.
And the radius of curvature of the inlet side 18 is 10
μm or less, and the thickness of the orifice plate 1
T _FourMay be 20 μm or less.

The length L of the linear portion 12 is
Rate 1 depth, ie, thickness t _Four1/10 for
It may be in the range of １ ／ to １ ／.

As described above, the method for manufacturing an ink jet recording head according to the present embodiment is advantageous in the following points.

That is, the diameter φ ₁ of the outlet side 19 is 10 μm.
m or less, the curved portion 14 can be formed by performing exposure with the mask on which the gradation is formed,
The linear portion 12 can be formed by using exposure with a mask on which no gradation is formed.

A plurality of layers on which the discharge ports 3 were formed were formed on the metal substrate 9 having substantially the same thermal expansion coefficient as the first layer 10 and the second layer 11. As a result, at the stage when the temperature is returned from the curing temperature at the time of curing to finally form the molecular bond of the photosensitive resin to room temperature, the release surface 6a not in contact with the substrate is temporarily joined to the substrate. Since the degree of thermal shrinkage with the temporary bonding surface 6b side (see FIG. 3 (c)) can be substantially equalized, the curl-like warpage of the formed orifice plate 1 is reduced, and the substantially flat orifice plate is reduced. 1 can be formed.

Further, since the layer on which the discharge ports 3 are formed is formed on the metal substrate 9 instead of the silicon substrate, the time required for removing the substrate can be reduced. That is, the silicon substrate forms a passivation film in the acid and does not dissolve well. Further, the silicon substrate is soluble in HF (hydrofluoric acid) but is damaged up to the photosensitive resin film. Further, it is soluble in alkali but requires a considerable dissolution time.
Even in a strong alkaline solution of NaOH of about 5 to 10% by mass,
It takes about 0 hours. On the other hand, in the case of the present embodiment, the metal substrate 9 which is easily dissolved in an acid such as iron, copper nickel, tin, or the like can be reduced to about 4 at room temperature by using dilute hydrochloric acid, dilute sulfuric acid, or a mixed acid with these organic acids. The substrate can be dissolved and removed in about time. Also, while silicon substrates are expensive, these general metal plates are inexpensive and economically advantageous.

Further, in the case of the present embodiment, the metal substrate 9 is dissolved and removed so as to leave the metal substrate 9 in a lattice shape.
The lattice-shaped metal substrate 9 can be used as a holding substrate for handling the orifice plate 1, so that the rigidity of the orifice plate 1 during handling can be increased. In other words, the substrate whose rigidity is increased by the lattice-shaped metal substrate 9 can be held and handled by suction or suction, and good bonding with the inkjet recording element 200 can be performed. In particular, the metal substrate 9 made of nickel or an iron plate reacts with magnetism, so that it can be magnetically attracted and conveyed, and can be handled very easily.

Further, by forming slight irregularities on the bonding surface 7 of the second layer 11, the bonding characteristics to the ink jet recording element 200 can be improved. The unevenness may have a depth of 1 μm or less.

Further, the opening hole 20 is formed in the orifice plate 1.
And the means for supplying a drive signal and electric power for driving the ink jet recording head 300 by forming the electrode 21.
00 can be electrically bonded.

The first layer 10 is formed by dissolving an inorganic substance in n-methylpropidone or the like in the form of alkoxide, methoxide or proxide, and forming a first layer 10 with a mixed solution of this solution and a photosensitive resin. When exposing layer 10 of
Scattering and absorption of ultraviolet light in the first layer 10 can be suppressed, whereby the straight portion 12 can be processed into a straight shape.

Further, tetraethoxytitanium is dissolved in n-methylpyrrolidone, and Teflon particles are suspended in this solution together with a fatty acid-based surfactant, mixed with a solution of a photosensitive resin, and mixed with the first layer 10 or 10. By forming the ink-repellent layer, the abrasion resistance to paper dust and the like can be improved.

Next, the ink jet recording head 3 formed by joining the orifice plate 1 formed as described above and the ink jet recording element 200 is formed.
FIG. 9 shows a perspective view of an example of an ink jet recording apparatus which can be mounted with a color ink jet recording head manufactured by using a plurality of 00s.

A guide shaft 1009 is mounted on the main body chassis 1012, and a carriage 1008 is supported on the guide shaft 1009 so as to be slidable in the direction of arrow B ". The carriage 1008 is driven by a carriage motor 1011 via a belt. Combined drive pulley 10
A portion of the carriage 1008 is fixed to a timing belt 1010 stretched between the motor 13 and the idler pulley 1014, and can reciprocate in the direction of arrow B ″ along the guide shaft 1009 according to the rotation of the carriage motor 1011. It is.

A recording head cartridge 1017 detachably mounted on the carriage 1008 is a color ink jet recording head comprising four ink jet recording heads 300 for discharging BK (black), Y (yellow), M (magenta), and C (cyan). It has a recording head 301.
Further, the recording head cartridge 1017 includes BK, Y, M, C for supplying to each ink jet recording head.
The ink tank 1015 for storing each of the inks is held detachably. The ejection port 3 of each ink jet recording head 300 is formed to face downward in the figure.

The print head cartridge 1017 is mounted on the back of the main body chassis 1012 via a flexible cable 1002 for transmitting and receiving a current and a signal for driving the print head cartridge 1017, and for controlling the printing apparatus main body. Is electrically connected to a control board (not shown).

A transport roller (not shown) driven by a recording paper transport motor (not shown) transports the recording paper 1004 in the sub-scanning direction indicated by arrow A ″.

Recording paper 1004 conveyed to the recording area
In contrast, recording is performed by discharging the ink supplied from the ink tank 1015 from the discharge port 3 of each ink jet recording head.

As described above, the numerical values, materials, and the like used in the description of the present embodiment are merely examples, and the present invention is not limited to these.

[0124]

EXAMPLES Examples of the embodiments of the present invention will be described below, but the present invention is not limited to these examples.

The drawings and reference numerals used in the description are the same as those used in the above embodiment. (First Embodiment) In this embodiment, the outlet side 19 of the discharge port 3 is used.
Diameter phi ₁ is to prepare the orifice plate 1 of 8μm and 4 [mu] m.

First, a method of manufacturing the orifice plate 1 in the case where the diameter φ ₁ of the outlet side 19 of the discharge port 3 is 8 μm will be described.

On a metal substrate 9 made of an amorphous iron plate, an epoxy-based positive photosensitive resin was applied at 350 rpm.
Spin coat for 40 seconds at a thickness t ₁ ≒ 11 μm,
Pre-baking at 5 ° C. for 5 minutes, as shown in FIG.
After the layer 10 is formed, as shown in FIG. 3B, the epoxy-type positive photosensitive resin is again applied at 300 rpm and 3 rpm.
0 seconds, spin-coat at thickness t ₂ ≒ 12 μm, 80 ° C.
The second layer 11 was formed by pre-baking for 5 minutes.

Next, as shown in FIG.
m at the mask 22 that transmits the exposure light only in the area of m / m.
with ultraviolet exposure in cm ^2, then 3 (d), the gradation portion 25 having a diameter a plurality of micro transmitting portion 27 of the following diameters 1μmφ around the orifice exit diameter corresponding portion 26 of 8μm was formed UV exposure was performed at 3 J / cm ^{2 using a} gradation mask 23 having

Thereafter, the exposed portions were removed with methyl isobutyl ketone. In this way, as shown in FIG. 3E, a substrate with the discharge ports 3 opened was formed on the metal substrate 9.

Next, the substrate was placed in a post-baking apparatus and cured at 180 ° C. for 30 minutes.

As a result, the diameter φ of the inlet side 18 of the discharge port 3
₂ is about 20 μm, and it is possible to form a nodal-shaped curved portion 14 having a gentle cross section near the entrance,
And a diameter phi ₁ of the outlet side 19 is 8 [mu] m, the vicinity of the outlet is a straight line shape, it was possible to form a straight portion 12 continues smoothly to the curved portion 14.

Thereafter, this substrate was washed with a 15% hydrochloric acid solution for 5 minutes.
The metal substrate 9 was removed at 0 ° C.

By the way, an iron plate having a mirror surface degree of maximum height Rmax of 0.3 μm or less has a thickness of 0.15 m.
m is the thinnest among the commercially available products.

However, in this case, it takes time to remove the holding substrate by wet etching or the like. Therefore, in the present embodiment, an investigation was performed using an amorphous iron plate as a substrate used for etching. This amorphous iron plate has a thickness of about 40 μm and responds to a magnetic field. The above-mentioned UV-curable resin spin coating was performed by adsorbing and fixing this amorphous iron plate disk substrate to an electromagnetic adsorption plate.

The metal substrate 9 made of a thin and flexible amorphous iron plate is spin-coated and pre-baked, exposed, developed, post-baked, and electrically-adsorbed and desorbed by switching the electromagnetic adsorption holding table. Through the etching process, the orifice plate 1 having the discharge port 3 in which the ink inlet side 18 is curved and the outlet side 19 forms a straight line can be manufactured satisfactorily. In the post-baking, since it was in a region where the magnetic attraction force was lost, it was fixed in a fixed base having an opening partly in a sandwiching manner, and post-baked at a temperature of 180 ° C.

Since the thickness of the metal substrate 9 is as thin as about 40 μm, the removal rate by the etching is high, and the partial etching can be performed satisfactorily in about one hour.

As described above, by using the substrate that can be magnetically fixed, the office plate 1 can be carried and moved well even when an amorphous iron plate as thin as 40 μm is used.

As described above, the orifice plate 1 having a predetermined thickness of about 14 μm was manufactured as shown in FIG.

The orifice plate 1 of this example formed by spin coating twice on the metal substrate 9 was in a good condition with almost no warpage.

Next, a method of manufacturing the orifice plate 1 when the diameter φ ₁ of the outlet side 19 of the discharge port 3 is 4 μm will be described.

First, as shown in FIG.
After spin-coating an epoxy-based photosensitive resin to a thickness of 8 μm on the top and pre-baking at 80 ° C. for 3 minutes, FIG.
As shown in (b), ultraviolet exposure was performed at 5 J / cm ² to form the first exposed portion 15 using a mask 22 that transmits exposure light only in a region having a diameter of 4 μm. Then 80 ° C
For 2 minutes after baking.

Next, as shown in FIG. 7C, the epoxy photosensitive resin 10 was again spin-coated with a thickness of 8 μm, and similarly prebaked at 80 ° C. for 3 minutes. After that, the alignment is sufficiently performed, and as shown in FIG. 7D, 5 J / cm ² is applied to a gradation mask 23 having a gradation portion 25 formed around an orifice outlet diameter corresponding portion 26 having a diameter of 4.5 μm. Was exposed to ultraviolet light.

Next, the first reaction was carried out with methyl butyl isoketone.
The exposed portion 15 and the second exposed portion 16 were removed. In this way, as shown in FIG. 7E, a substrate with the discharge ports 3 opened was formed on the metal substrate 9.

Next, the substrate was placed in a heat treatment post-baking apparatus and cured at 180 ° C. for 30 minutes. Thereafter, this was subjected to etching removal treatment with a 20% hydrochloric acid solution at a temperature of 30 ° C.

As described above, as shown in FIG. 7 (f), the diameter φ ₂ of the inlet side 18 of the discharge port 3 is about 16 μm, the curved portion 14 having a gentle cross section near the inlet, and the diameter of the outlet side 19 phi ₁ is in the 4 [mu] m, the vicinity of the outlet is able to produce an orifice plate 1 having a discharge outlet 3 and the straight portion 12 in the shape of a straight line is formed.

The epoxy photosensitive resin used here is:
This is Adeka Optoma-KS-820 from Asahi Denka. Since this Adeka Optomer KS-820 is formed from a main component and a photocatalytic agent, an ultraviolet-sensitive resin having a constant curing speed and photospeed can be obtained by mixing them at a predetermined compounding ratio. .

By using such a photosensitive resin whose curing speed and photosensitive speed can be adjusted and using a material such as polyamide imide, polysulfone, or polyphenylene sulfide, the curved portion 14 and the linear portion as in this embodiment can be obtained. It is possible to form the discharge port 3 having a diameter φ ₁ of 8 μm or less on the outlet side 19 having the nozzle 12.

Next, a method of manufacturing the ink jet recording head 300 will be described.

The ink jet recording head 300 includes a recording element substrate 70 on which the electrothermal transducer 100 is provided, and an ink flow path forming member 80 on which an ink flow path 81 is formed.
And the orifice plate 1 in which the discharge port 3 is formed.

The electrothermal transducer 100 of the recording element substrate 70
Are provided so as to correspond to the respective ink flow paths 81 and face the respective ejection ports 3. An electrothermal transducer 100 formed on the recording element substrate 70;
And an electric wiring (not shown), such as Al, for supplying electric power to the device are formed by a film forming technique.

In the ink flow path 81, after a bonding strength assisting process is performed on the recording element substrate 70 with a silane coupling agent or the like, an epoxy photosensitive agent is spin-coated at 16 μm.
Next, a 1.5 μm thick epoxy-based photosensitive adhesive is spin-coated, then pre-baked, exposed to ultraviolet light with a mask having a predetermined ink flow path pattern, and further developed with methyl isobutyl ketone. The film was formed by performing a curing treatment at 180 ° C. for 30 minutes.

Next, after positioning the orifice plate 1 with respect to the ink jet recording element 200 on which this pattern was formed, the orifice plate 1 was hot-press bonded to the ink jet recording element 200. The conditions of the hot press bonding were 200 ° C., 196 kPa, and 30 seconds.
The adhesive used was an epoxy polymer manufactured by Soken Chemical.

The ink jet recording head 300 manufactured as described above was mounted on the ink jet recording apparatus shown in FIG. 9, and ink jet was performed.

As a result, at a discharge frequency of 15 KHz,
The inkjet recording head 300 having the ejection openings 3 of φ ₁ = 8 μm had an average inkjet ejection amount of about 3.5 pl after 1 million operations. Also, a discharge port 3 of φ ₁ = 4 μm
The average ink jet ejection amount of the ink jet recording head 300 having about 1 pl was about 1 pl under the same conditions. However, the shape of the electrothermal conversion element 100 provided in the ink jet recording element 200 is changed according to the size of the diameter φ ₂ of the inlet side 18 of the discharge port 3.

When the electrothermal conversion element 100 for φ ₁ = 8 μm is used for φ ₁ = 4 μm, although the amount of the discharged ink is considerably reduced due to the flow resistance due to the size of the discharge port 3, a stable ink jet is obtained. Discharge was possible.

On the other hand, the electrothermal conversion element 1 for φ ₁ = 4 μm
Sample _No. 00 had a small foaming volume for φ ₁ = 8 μm, and it was impossible to perform inkjet discharge.

As described above, it has been difficult to satisfactorily eject ink droplets such as 3 pl and 1 pl with a conventional ink jet recording head. However, with the ink jet recording apparatus equipped with the ink jet recording head 300 of this embodiment, it is difficult. It was confirmed that a perfect color image could be formed. (Second Embodiment) The surface 5 of the orifice plate 1 is usually called a face surface, but it is desirable that the surface be an ink-repellent surface. Although this thickness is not particularly important in dimensions, it is desired that the ink-repellent surface is not consumed, and is formed to a thickness of about 1 μm or less.

However, it is not preferable that the ink-repellent portion non-uniformly drips into the inside of the ejection port 3 because the ink ejection direction varies. Therefore, it is common to form a layer by depositing or coating.

Therefore, in the present embodiment, on the metal substrate 9 made of copper, a particle size of 0.1
8 μm polytetrafluoroethylene powder was suspended and mixed in an amount of 8% by weight, and this was formed into a thickness of about 0.8 μm by spin coating. Next, an epoxy photosensitive resin was spin-coated thereon to form a first layer 10 and a second layer 11 having a thickness of t ₃ = 23 μm, and an orifice plate 1 was formed.

When ink is dripped on the front surface 5 of the orifice plate 1, which is the face surface, the ink becomes droplets,
When the orifice plate 1 was tilted by 15 degrees or more, it fell completely and did not adhere to the surface 5 of the orifice plate 1. Thus, it was confirmed that the face surface 5 of the orifice plate 1 was ink-repellent.

The length L of the linear portion 12 of the orifice plate 1 having the ink-repellent layer is about 5 μm, the diameter φ ₂ of the curved portion 14 on the entrance side 18 is about 20 μm,
The thickness of the orifice plate 1 was about 14.3 μm.

The diameter φ ₁ on the outlet side 19 of the discharge port 3 was almost unchanged and was about 8 μm.

Therefore, the diameter φ ₁ of the outlet side 19 of the discharge port 3
The diameter φ ₂ of the inlet side 18 is about 250% of the size of
And the ratio L / t ₄ of the length L of the straight portion 12 to the thickness t ₄ of the orifice plate 1 is about 0.3 to 0.4.
Was within the range.

As a result of changing the pattern of the gradation mask 23 and the exposure conditions, 0.2 ≦ L / t ₄ ≦ 0.
In the case of No. 8, it became clear that good landing accuracy of ink-jet droplets could be obtained. (Third Embodiment) In the first embodiment, the first layer 10 and the second layer 11 are made of an epoxy-based photosensitive resin. In this embodiment, these layers are made of polyimide photosensitive resin. It was produced using.

The steps of forming each layer in this embodiment will be described below.

First, as shown in FIG.
9 on the positive photosensitive resin of polyimide 500rpm
m, 60 seconds, thickness t₁Spin coat at で 15μm,
Pre-bake at 85 ° C. for 15 minutes to form a first layer 10
After that, as shown in FIG.
Di-type photosensitive resin is applied at 500 rpm for 60 seconds with a thickness t. _Two
Spin coat at about 15 μm with ≒ and press at 80 ° C for 20 minutes.
The second layer 11 was formed by rebaking.

Next, as shown in FIG.
m at the mask 22 that transmits the exposure light only in the area of m / m.
with ultraviolet exposure in cm ^2, then 3 (d), the gradation portion 25 having a diameter a plurality of micro transmitting portion 27 of the following diameters 1μmφ around the orifice exit diameter corresponding portion 26 of 8μm was formed UV exposure was performed at 3 J / cm ^{2 using a} gradation mask 23 having

Thereafter, the exposed portion was immersed in a tetramethylammonium hydroxide solution at 25 ° C. for 1 minute and developed and removed.

Next, as a rinsing treatment, the substrate was immersed in a 1% aqueous acetic acid solution for 30 seconds, washed with a pure water aqueous solution, and then washed with a 6% aqueous solution.
By removing the moisture by drying at a temperature of 5 ° C. for 60 minutes, FIG.
As shown in (e), a substrate with the discharge port 3 opened was formed on the metal substrate 9.

Next, this substrate was placed in a post-baking apparatus, and a curing treatment was performed at 170 ° C., 260 ° C., and 330 ° C. for 30 minutes each.

As a result, the diameter φ of the inlet side 18 of the discharge port 3
₂ is about 20 μm, a cross-sectional shape can form a gentle curved portion 14 near the entrance, and the exit side 1
9 diameter phi ₁ is 8μm, the vicinity of the outlet is able to form a straight portion 12 in the shape of a straight line.

Thereafter, this substrate was washed with a 15% hydrochloric acid solution for 5 minutes.
The metal substrate 9 was removed at 0 ° C.

In this way, as shown in FIG. 3F, an orifice plate 1 having a predetermined thickness of about 15 μm was manufactured.

The orifice plate 1 of this example formed by spin coating twice on the metal substrate 9 was almost in a good condition without any warpage. (Fourth Embodiment) In this embodiment, a straight orifice plate in which the straight portion of the discharge port is not tapered was manufactured.

A method of manufacturing the orifice plate having the straight straight portion will be described below with reference to FIG. The reference numerals used in the description are the first layer 1
Except for 10, the second layer 111, and the straight portion 116, the same reference numerals as those in the above-described embodiment and each example are used.

First, tetramethoxysilane, which is a methoxide of SiO ₂ , was dissolved in n-methylpyrrolidone, and this was mixed with a solution of a photosensitive polyimide dissolved in a similar solvent (step 5 in the flowchart shown in FIG. 8). .
Polyimide is a polycondensation type of biphenyltetracarboxylic dianhydride and aromatic zoamine (BPDA type polyimide)
Ube Industries' Upifine was used.

For tetramethoxysilane, a silplex consisting of a silicone intermediate product precursor manufactured by Toray Silicone Co., Ltd. was used. Since the viscosity of the solution of the present photosensitive polyimide and tetramethoxysilane was about 8 Pa · s, the viscosity was 500 r.
The first layer 11 as shown in FIG. 10A is formed by spin-coating on a metal substrate 9 made of iron by spin coating at 60 pm for 60 minutes, and then performing pre-baking at 90 ° C. for 20 minutes.
0 was formed.

Next, a solution containing only the photosensitive polyimide was added to 50 times.
Spin coating was performed at 0 rpm for 60 seconds, and pre-baking was performed at 85 ° C. for 15 minutes to form a second layer 111 as shown in FIG. 10B.

As a result, a layer having a thickness t ₃ ≒ 28 μm was obtained as shown in FIG. The layer thus formed was exposed to ultraviolet light having a wavelength of 365 nm using a mask on which an orifice pattern was formed. The amount of ultraviolet light at the time of exposure was ² J / cm ² . The mask pattern is
The configuration was made up of a portion having a diameter of 20 μm where gradation was formed and a portion having a diameter of 8 μm where no gradation was formed. The average transmittance of the ultraviolet rays in the gradation from the portion having a diameter of 20 μm to the portion having a diameter of 8 μm is a pattern that increases as a quadratic function.
4 was formed. In this embodiment, since the positive photosensitive resin is used, the ultraviolet ray transmittance is 100% in a portion having a diameter of 8 μm, and the ultraviolet ray transmittance is 0% in a portion other than a gradation portion and a portion having a diameter of 8 μm. If a negative photosensitive resin is used, the pattern is reversed.

In this example, the positive type photosensitive resin was used because the BPDA type photosensitive polyimide solution exhibited a slightly brownish color, and the color tone became transparent as the ultraviolet light was transmitted, thereby improving the transmittance. The reason for this is that photolithography can be performed even with a thick photosensitive film by taking advantage of its characteristics. In addition, in the case of a negative photosensitive resin, the color becomes further brown as the ultraviolet light is transmitted. Therefore, it takes much time and labor for the exposure process to perform good photolithography with a prebaked film having a thickness of t ₃ = 28 μm. Becomes

Next, a tetramethylammonium solution (T
MAH aqueous solution) to form an orifice 6
Development processing was performed for 0 seconds. Then, 20% with 1% acetic acid solution
After post-processing development for 20 seconds, washing with pure water for 20 seconds
The state was as shown in FIG. Then, moisture is dried in a 60 ° C. constant temperature bath, and 170 ° C., 260 ° C., 350 ° C.
For 20 minutes each. As a result, a metal substrate 9 having an orifice formed thereon and a polyimide layer having a thickness of about 16 μm was formed.

Next, the metal substrate 9 was immersed in a 10% hydrochloric acid solution for 10 hours, and the thickness t ₄ = as shown in FIG.
A 16 μm orifice plate 1 was formed.

Disconnection of the discharge port 3 of the orifice plate 1
As a result of observing the surface with a microscope, the thickness t _Five= 7μm noodles
Curved portion 14 having a kana curve and thickness t₆= 9 μm strike
The straight part 17 is formed from the rate part 17.
Formed at right angles to the surface 5 of the orifice plate 1
I was

At this time, the content of SiO _{2 in} the orifice plate 1 was about 5%. Therefore, since this orifice plate has a two-layer structure and the thickness is almost half, it was determined that the SiO ₂ content in the layer containing SiO ₂ was about 10%.

Further, it was confirmed that a good image could be formed by an ink jet recording apparatus equipped with the ink jet recording head 300 of this embodiment using the orifice plate 1 having the straight portion 17. (Fifth Embodiment) In this embodiment, an orifice plate 1 in which the abrasion resistance of the ink-repellent layer is improved was manufactured.

Hereinafter, a method for forming the ink-repellent layer in this embodiment will be described.

First, 40% by mass of tetraethoxytitanium was added.
And dissolved in n-methylpyrrolidone. Next, about 2 μm of Teflon particles having a diameter of 0.1 μm were added to this solution.
0% by mass and further suspended with 0.2% by mass of a fatty acid-based surfactant. Then, a photosensitive polyimide solution and 50:
The mixture was mixed at a ratio of 50. Next, the solution was brought to 1500 rpm
m, spin-coated on the metal substrate 9 for 60 seconds, and pre-baked at 80 ° C. for 30 minutes. The thickness of the layer at this time is
Approximately 1 μm, which is
By performing post-baking at 0 ° C., an ink-repellent layer having a thickness of about 0.65 μm was obtained.

On this prebaked layer, as in the third embodiment, spin coating of a mixed solution of a polyimide photosensitive resin and tetramethoxysilane, prebaking, and then spin coating of only the polyimide photosensitive resin. After performing pre-bake, UV exposure with a mask and subsequent development etching,
A predetermined orifice plate 1 was obtained by rinsing, washing, drying, three-stage post-baking, and dissolving and removing the iron plate substrate.
At this time, the thickness t ₄ of the orifice plate 1 is about 1
6.5 μm, and the surface 5, which is the face surface, showed ink repellency.

Further, in this embodiment, while keeping the thickness of the orifice plate 1 constant, the ratio of the thickness of the spin coat layer of the mixed solution of polyimide and tetramethoxysilane to the thickness of the spin coat layer of only polyimide is maintained. The various orifice plates 1 were manufactured while changing the shape of the exposure pattern and the shape of the exposure pattern. The shape of the orifice plate 1 was formed such that the cross section of the discharge port 3 had a gentle curved portion 14 and the linear portion 12 parallel to the ink jet discharge direction. It is possible to
It was confirmed that good inkjet discharge was possible.

It was also confirmed that a good image could be formed by an ink jet recording apparatus equipped with the ink jet recording head 300 using the orifice plate 1 of this embodiment. (Sixth Embodiment) In this embodiment, the content of the inorganic substance, particularly SiO ₂ , in the polyimide was varied, and the allowable value was measured.

As a result of changing the concentration of the mixed solution of tetramethylsilane and changing the content, it was possible to form a film up to 80% by mass. When the content of SiO ₂ is around 80% by mass, it becomes quite crisp, but it can be made into a film about 15 mm square, and it can be handled because a photosensitive resin layer of only polyimide is formed on it. there were.

When the content of SiO _{2 in} the polyimide was 3% by mass, a vertical cross-section by photolithography was not clearly confirmed, and in a rubbing test on the end face of the paper, it was slightly damaged. Was formed. However, Si
When the content of O ₂ was 5% by mass, vertical photolithography was possible, and scars were scarcely formed even when rubbed on the end face of the paper.

The content of SiO ₂ is preferably from 5 to 80% by mass, but the content of SiO ₂ including flexibility / strength / hardness is more preferably in the range of about 10 to 40% by mass.

[0194]

As described above, according to the present invention, since the orifice plate is manufactured from the photosensitive resin using the gradation mask, even if the diameter on the outlet side is 10 μm or less, the orifice on the ink inlet side has a curved orifice. Can be formed. For this reason, even in the case of a small droplet that has a very small ejection of the ink jet, the ejection direction is stable, there is little variation, and the landing accuracy of the ink jet droplet can be improved. This allows
It is possible to form a high-quality color image even if the ink-jet droplets are minute.

[Brief description of the drawings]

FIG. 1 is a perspective view and an exploded perspective view of an inkjet recording head according to an embodiment of the present invention.

FIG. 2 is a plan view of the ink jet recording element shown in FIG.

FIG. 3 is a diagram illustrating a procedure for forming an orifice plate of the inkjet recording head of the present invention.

FIG. 4 is a flowchart illustrating a procedure for forming an orifice plate of the inkjet recording head of the present invention.

FIG. 5 is a diagram schematically illustrating the transmittance of exposure light in a gradation portion of a gradation mask.

FIG. 6 is a schematic plan view of a gradation mask.

FIG. 7 is a diagram illustrating another procedure for forming an orifice plate of the inkjet recording head of the present invention.

FIG. 8 is a flowchart when a step of uniformly dispersing an inorganic substance in a photosensitive resin is added.

FIG. 9 is a perspective view of an example of an ink jet recording apparatus on which a color ink jet recording head manufactured by using a plurality of the ink jet recording heads of the present invention can be mounted.

FIG. 10 is a diagram illustrating a method for manufacturing an orifice plate having a straight portion in a straight shape according to a fourth embodiment of the present invention.

FIG. 11 is a schematic partial cross-sectional view of an example of a conventional ink jet recording head having a straight portion and a curved portion on a wall surface of a discharge port.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Orifice plate 3 Discharge port 5 Surface 6a Release surface 6b Temporary bonding surface 9 Metal substrate 10, 110 First layer 11, 111 Second layer 12 Linear portion 14 Curve portion 15 First exposure portion 16 Second exposure portion 17 Straight part 18 Inlet side 19 Outlet side 20 Opening hole 21 Electrode 22 First mask 23 Second mask 24 Exposure light 25 Gradation part 26 Orifice outlet diameter corresponding part 27 Micro transmission part 70 Recording element substrate 80 Ink flow path forming member 81 Ink flow path 100 Electrothermal conversion element 200 Inkjet recording element 300 Inkjet recording head 301 Color inkjet recording head 1002 Flexible cable 1004 Recording paper 1008 Carriage 1009 Guide shaft 1010 Timing belt 1011 Carriage motor 101 Body chassis 1013 driving pulley 1014 idler pulley 1015 ink tanks 1017 recording head cartridge

Claims (34)

[Claims] 1. An ink jet recording element having a liquid flow path provided with an energy generating element for generating energy used for discharging ink, and an ink jet recording element joined to the ink jet recording element and provided in each of the liquid flow paths. In a method for manufacturing an ink jet recording head having an orifice plate in which a plurality of orifices communicating with the respective liquid flow paths are formed at corresponding portions, a thermal expansion coefficient of the photosensitive resin to be the orifice plate is substantially equal to the thermal expansion coefficient. Forming at least one photosensitive resin layer made of the photosensitive resin on a metal substrate having a coefficient of thermal expansion, a portion corresponding to a minimum diameter of each of the orifices and a portion corresponding to a maximum diameter of each of the orifices; Using a gradation mask with a transmittance distribution such that the transmittance of the exposure light between The photosensitive resin layer was exposed treated, method of manufacturing an ink jet recording head which comprises a step of part of the side section of the orifice to form the respective orifice so as to curve. 2. a step of forming a first photosensitive resin layer made of the photosensitive resin on a metal substrate having a coefficient of thermal expansion substantially equal to the coefficient of thermal expansion of the photosensitive resin layer; The method according to claim 1, further comprising: forming at least one photosensitive resin layer on the conductive resin layer by laminating the photosensitive resin layer. 3. A step of exposing the photosensitive resin layer to light using a mask having no transmittance distribution so that a part of the side cross section becomes a straight line to form each of the orifices. Item 3. The method for manufacturing an ink jet recording head according to Item 1 or 2. 4. A material exhibiting ink repellency is contained,
4. The method according to claim 2, further comprising: a step of forming the first photosensitive resin layer as an ink-repellent layer; and a step of laminating at least two photosensitive resin layers on the ink-repellent layer. 5. Of manufacturing an inkjet recording head. 5. The method according to claim 2, further comprising the step of forming the first photosensitive resin layer with a mixed solution of the photosensitive resin and a solvent in which an inorganic substance is dissolved and contained in the form of alkoxide, methoxide or proxide. The method for manufacturing an ink jet recording head according to any one of the above items. 6. The method according to claim 2, wherein a metal having magnetism is used as the metal substrate. 7. The method according to claim 6, wherein the metal substrate made of iron or nickel is used. 8. The method according to claim 2, wherein a metal that can be dissolved and removed in a shorter time than the time required for dissolving and removing silicon is used as the metal substrate. 9. The method according to claim 2, wherein the metal substrate made of zinc or tin is used. 10. The method according to claim 2, further comprising forming the first photosensitive resin layer on a mirror-finished surface of the metal substrate. . 11. The method according to claim 2, further comprising the step of forming the first photosensitive resin layer on a surface of the metal substrate having a maximum height Rmax of 0.5 μm or less. 2. The method for manufacturing an ink jet recording head according to claim 1. 12. The method of manufacturing an ink jet recording head according to claim 2, further comprising a step of forming a holding portion of said orifice plate by partially dissolving and removing said metal substrate. 13. When sequentially laminating the photosensitive resin layers in the layer forming step, after the step of prebaking the photosensitive resin layer and the step of drying the photosensitive resin layer are completed, 3. The method according to claim 2, further comprising the step of laminating a photosensitive resin layer.
12. The method for manufacturing an ink jet recording head according to any one of items 11 to 11. 14. A plurality of irregularities having a maximum height Rmax of 1 μm or less on a surface of the last photosensitive resin layer to be joined to the ink jet recording element, of the second photosensitive resin layer formed last. 2. The method according to claim 1, further comprising the step of:
3. The method for manufacturing an ink jet recording head according to any one of items 3. 15. The method according to claim 1, further comprising a cutting step of cutting the plurality of orifice plates manufactured together as individual orifice plates before joining to the ink jet recording element. Of manufacturing an inkjet recording head. 16. The method according to claim 1, further comprising a cutting step of cutting the plurality of orifice plates manufactured together as individual orifice plates after joining to the ink jet recording element. A method for manufacturing an ink jet recording head. 17. The method according to claim 15, wherein a laser is used for separation in the cutting step. 18. An ink jet recording element having a liquid flow path provided with an energy generating element for generating energy used for discharging ink, and an ink jet recording element joined to the ink jet recording element and provided in each of the liquid flow paths. 18. A method for manufacturing an ink jet recording head according to claim 1, further comprising an orifice plate formed with a plurality of orifices communicating with the respective liquid flow paths at corresponding portions. An ink jet recording head manufactured by the following method. 19. The ink jet recording head according to claim 18, wherein the diameter of the orifice on the inlet side where the ink flows in is at least 1.5 times the diameter on the outlet side where the ink is discharged. 20. The ink jet recording head according to claim 18, wherein the opening area of the orifice on the inlet side where the ink flows is at least 2.25 times the opening area on the outlet side where the ink is discharged. 21. The ink jet recording head according to claim 18, wherein the diameter of the outlet side is 10 μm or less. 22. The ink jet recording head according to claim 18, wherein a radius of curvature of the entrance side is 10 μm or less. 23. The orifice plate having a thickness of 20
The ink jet recording head according to any one of claims 18 to 22, wherein the diameter is not more than μm. 24. The ink jet recording head according to claim 18, wherein the photosensitive resin is an epoxy resin. 25. The ink jet recording head according to claim 18, wherein the photosensitive resin is a polyimide resin. 26. The ink jet recording head according to claim 18, wherein the orifice plate has an opening for supplying an electric signal to the energy generating element. 27. An ink jet recording element having a liquid flow path provided with an energy generating element for generating energy used to discharge ink, and an ink jet recording element joined to the ink jet recording element and provided in each of the liquid flow paths. An ink jet recording head having an orifice plate formed with a plurality of orifices communicating with the respective liquid flow paths at corresponding portions, respectively, wherein the ink jet recording head according to any one of claims 3 to 17, An ink jet recording head manufactured by the following method. 28. The length of a straight portion having a straight side cross section is 1/10 to 1/2 of the thickness of the orifice plate.
The ink jet recording head according to claim 27, wherein 29. The photosensitive resin layer in which the linear portion is formed contains 5 to 80% by mass of an inorganic substance, and
29. The ink jet recording head according to claim 27, wherein an area of a surface of the linear portion perpendicular to an ink ejection direction is constant. 30. An ink jet recording element having a liquid flow path provided with an energy generating element for generating energy used for discharging ink, and an ink jet recording element joined to the ink jet recording element and provided in each of the liquid flow paths. An ink jet recording head having an orifice plate formed with a plurality of orifices communicating with the respective liquid flow paths in corresponding portions, respectively, wherein the method for manufacturing an ink jet recording head according to any one of claims 4 to 17 is provided. An ink jet recording head manufactured by the following method. 31. The ink jet recording head according to claim 30, wherein the ink-repellent surface of the ink-repellent layer is a surface of the orifice plate on the outlet side from which ink is ejected. 32. The heat generating element according to claim 1, wherein the energy generating element is an electrothermal converter that generates thermal energy for ink ejection.
32. The inkjet recording head according to any one of items 8 to 31, wherein 33. The ink jet recording head according to claim 32, wherein the ink is ejected from an ejection port formed by the orifice by using film boiling generated in the ink by thermal energy applied by the electrothermal transducer. 34. A transport means for transporting a recording medium, and ejecting ink to perform recording on the recording medium.
34. An ink jet recording apparatus, comprising: a holding unit for holding the ink jet recording head according to any one of Items 33 to 33 and reciprocating in a direction substantially perpendicular to the transport direction of the recording medium.