JP2744472B2 - Ink jet recording head and method of manufacturing the same - Google Patents

Description

The present invention relates to a substrate for an ink jet recording head, an ink jet recording head having the same, and a method for manufacturing the same.

[Related Art] The ink jet recording method is a recording method in which ink (recording liquid) is ejected from an ejection port provided in a recording head, and the ink is adhered to a recording material such as paper to perform recording. Extremely low generation, high-speed recording is possible, and there is no need to use specially configured recording paper.
It has many advantages and various types of recording heads have been developed.

Above all, a recording head of a type in which thermal energy is applied to ink to eject ink from ejection ports has advantages such as good response to a recording signal and easy arrangement of a large number of ejection ports at high density. .

A recording head used for such a recording method typically has a configuration as shown in a schematic perspective view of FIG. Specifically, an ejection port 101 provided for ejecting ink to form a flying droplet, a liquid path 102 for communicating with the ejection port and supplying ink, and a flying liquid for ejecting ink An electrothermal conversion element, which is a thermal energy generator 104A for forming a droplet and is provided in the liquid path 102 and has a heating resistor and an electrode for supplying a current to the heating resistor, A liquid chamber 103 for storing ink to be supplied in a flow path provided on the upstream side, and a protective film or the like having an action of increasing the ink resistance of the electrothermal conversion element is provided as necessary. I have.

Such a head is generally manufactured as shown in FIGS. 2 (a) to 2 (g). FIG. 2 is a schematic cross-sectional view showing a manufacturing process at a position where the recording head is cut at the portions A to A ′ shown in FIG. First,
Finally, a layer 251 partly serving as a heating resistor (hereinafter referred to as a heating resistor layer) and a layer 252 partly serving as an electrode (hereinafter referred to as an electrode layer) are formed on the support 253 (step ( a);
(B)). Next, the electrode layer 252 is patterned using a photolithography technique and an etching technique using the photoresist 254, and subsequently, the heating resistance layer 251 is similarly patterned to form a resistance heating element and an electrode (step (c)). )-(K)).

Specifically, after a photoresist 254 such as a photosensitive resin is laminated on the product (b) after the step (b) is completed (step (c)), the photo of the product (c) is photo-etched using a photomask. The pattern of the resist 254 is exposed (step (d)),
Next, the photoresist 254 of the product (d) is developed (step (e)). In the step (e), the photoresist 25
In No. 4, only unnecessary portions are removed in a desired pattern shape. Next, the exposed electrode layer 252 of the product (e) is removed by etching (step (f)), and the remaining resist portion 254 'of the product (f) thus manufactured is removed (step (g)). )). Thus, a desired pattern of the electrode layer 252 is formed.

The pattern of the heat generating resistance layer 251 is formed by the same steps as those for forming the pattern of the electrode layer 252. That is, the photoresist 254 'was laminated (step (h)), and the photoresist 254 ″ of the product (h) was subjected to pattern exposure (step (i)) using a photomask, and the pattern of the product (i) was exposed. The pattern of the heating resistor layer 251 is formed by developing the photoresist 254 ″, removing unnecessary portions (step (j)), and etching the heating resistor layer 251 where the product (j) is exposed (step (k)). Is done.

After that, the resist 254 is stripped (step (l)). Next, after forming a protective film 255 having a purpose such as ink resistance (step (m)), the photosensitive resin 256 is laminated (step (n)), and then exposed (step (o)). And developing (step (p)) to form a wall 256 'of a cured film of the patterned photosensitive resin ((m) to (m)).
(P)). This wall constitutes a fluid path wall which can be filled with liquid. Next, the top plate 257 is bonded on the wall 256 ', and then cut (not shown) to form an ejection port surface, thereby completing the ink jet recording head (step (q)).

[Problems to be Solved by the Invention] As described above, the manufacturing method conventionally used includes many steps, and in addition, some steps, particularly the etching step, take a long time, and a long manufacturing time is required. There was a point that needed to be improved. In addition, there is still room for improvement in that the positional accuracy of individual members is deteriorated because of the large number of patterning operations.

The present invention has been made in order to solve the above problems, and an object of the present invention is to provide a substrate for an ink jet recording head which can shorten the manufacturing time and has a good positional accuracy of each member, and an ink jet recording head having the same. To provide. It is another object to provide a method for producing them.

[Means for Solving the Problems] An ink jet recording head of the present invention has a discharge port for discharging a liquid, a heating resistor, and an electrode for supplying a current to the heating resistor, and discharges the liquid. An electro-thermal transducer that generates thermal energy used to perform the process, and a support that supports the electro-thermal transducer, wherein the support selectively uses a conductive material. To provide a layer in which the anodized region is anodized to completely insulate the anodized region, and a predetermined portion of the conductive portion remaining uninsulated in the layer is an electrode, and The heat resistance portion is characterized in that a portion of which resistance is higher than that of the electrode region by the anodic oxidation.

The method of manufacturing a recording head substrate of the present invention is a method of manufacturing a recording head substrate having an electrothermal transducer used for discharging liquid on a support, wherein a conductive material is formed on the support. Forming a layer and oxidizing at least a part of a surface region of the layer to form an electrode and a heating resistor of the electrothermal converter.

Another manufacturing method of the recording head substrate of the present invention is a method of manufacturing a recording head substrate having an electrothermal transducer used for discharging a liquid on a support, wherein a conductive material is provided on the support. Forming a layer of a material, oxidizing a part of the layer to make an insulator, and then oxidizing at least a part of the surface area of the remaining conductive part to form an electrode and a heating resistor of the electrothermal transducer Characterized by having a process of performing

The method for manufacturing an ink jet recording head according to the present invention is used for ejecting a liquid having an ejection port for ejecting a liquid, a heating resistor, and an electrode for supplying a current to the heating resistor. A method for manufacturing an ink jet recording head, comprising: an electrothermal converter that generates thermal energy; and a support that supports the electrothermal converter, comprising: providing a conductive material on the support; Selectively anodizing the conductive material to completely insulate the anodized region, and wherein a predetermined portion of the conductive portion remaining uninsulated is an electrode and And a portion of the conductive portion having a resistance higher than that of the electrode region due to the anodic oxidation is a heating resistor portion.

Another manufacturing method of the ink jet recording head of the present invention includes: (a) a step of forming a film exhibiting conductivity and heat resistance and capable of being anodized on a support; and (b) forming an electrode and a resistance heating element. (C) laminating a photosensitive composition, and (d) partially removing the photosensitive composition to form at least a discharge port and a wall member. (E) exposing a top plate; and (f) oxidizing the exposed surface of the film by anodic oxidation to form a heating resistor and to form an anode. Leaving a film that is not oxidized as an electrode.

 Hereinafter, a preferred example of the present invention will be described with reference to the drawings.

First, as an assembly drawing in FIG. 1, the present invention will be briefly described by using an ink jet recording head showing one embodiment. That is, the ink jet recording head to which the present invention is preferably applied is provided with an ejection port 101 provided for ejecting liquid represented by ink to form flying droplets, and an ejection port 1.
A liquid path 102 for supplying liquid to 01, a liquid chamber 103 provided upstream thereof for storing liquid supplied to liquid path 102,
A heat energy source for ejecting liquid to form flying droplets, a heating resistor provided corresponding to the liquid path 102, and at least a pair of electrodes electrically connected to the heating resistor, An ink jet recording head having an electrothermal transducer 104A formed on a substrate 105 and comprising a pair of electrodes and a heating resistor, wherein the substrate is formed of one material selected from a heating resistor portion and an electrode. The present invention also provides a method for manufacturing a substrate and a recording head of the same material oxidized from the same material. Further, such an ink jet recording head includes, for example, (a) a step of forming a film exhibiting conductivity and heat resistance and capable of being anodized on a support; and (b) forming an electrode and a resistance heating element. Anodizing the film other than the portion to form an insulator; (c) laminating the photosensitive composition entirely thereon; and (d) partially removing the photosensitive composition. A step of forming at least a discharge port and a side surface of a flow path and exposing the film at a portion to be a resistance heating element; (e) a step of bonding a top plate; and (f) a step of (e). A step of putting an electrolyte in a liquid chamber and a liquid path, oxidizing the exposed surface of the film by anodic oxidation, and forming a heating resistor. This will be described in detail with reference to FIGS. 3 (a) to 3 (k).

Incidentally, FIGS. 4 (a) to 4 (a) to 4 (a) to 4 (c) show schematic plan process diagrams of the products corresponding to FIGS. 3 (d), (e), (f) and (i), respectively.
(D). That is, FIG. 4 (a) is the same as FIG. 3 (d),
FIG. 4 (b) shows the case where the steps shown in FIG. 3 (e), FIG. 4 (c) are shown in FIG. 3 (f), and FIG. The state of the product is shown.

It should also be noted that the above-described schematic perspective view of the recording head shown in FIG. 1 does not always match the shape of the recording head shown in the manufacturing procedure described below.

First, a material that can be used for both the heating resistor and the electrode is formed on the support 5 such as glass ((a)). As this material, a material that exhibits heat resistance and conductivity after film formation and can be anodized can be used. For example, Ta, V, Nb, Zr, Mg, Zn, Ni, Gd, C
o. The thickness of the formed film (starting material film) 4 is preferably about 500 to 20000 °. The film formation method may be determined according to the material, and a generally known vacuum deposition method such as sputtering or vapor deposition can be suitably used.

Next, in the finished product, the resist 7 covers portions of the film 4 other than the portions that become the heating resistors and the electrodes. For this purpose, a conventionally known photolithography technique may be used ((b)-).
(D)).

Next, the portion of the film which is not covered with the resist 7 'is changed to an insulator by anodic oxidation (e), and then the resist 7' is peeled off (f). The processing solution used in this case includes:
Aqueous solutions of boric acid, tartaric acid, malonic acid, phosphoric acid and the like can be mentioned. These aqueous solutions are particularly suitable for the anodic oxidation of a Ta film.

Next, the photosensitive resin 8 such as a dry film is entirely laminated (g). After that, the photosensitive resin 8 is patterned by performing partial exposure and development to form a pattern 8 'of a cured layer of the photosensitive resin ((h) to (i)).
The cured layer defines a liquid path and a discharge port. In this step, any material that can be finely patterned after lamination, including a photosensitive resin, can be used. FIG. 4 (d) is a schematic plan view showing the completed steps, and FIG. 5 is a cross-sectional view of the completed product (a cross-sectional view corresponding to AA 'in FIG. 7) for reference. In FIG. 4, the hatched portion is a portion converted into an insulator by anodic oxidation, and the dot portion is a portion provided with the photosensitive composition.

As shown in FIG. 4 (d), the film of the portion to be the resistance heating element is not covered with the cured layer 8 'of the photosensitive resin at least after patterning, and the film of the portion to be the electrode is photosensitive. Care is taken so that the resin is covered with the cured layer 8 'of the conductive resin. However, this is a point to be considered in order to carry out the subsequent steps ((k) in the figure) within a range that does not hinder the operation. Naturally, there may be a portion where it is not necessary to consider such a point.

Next, a top plate 6 made of glass or the like is stuck on the hardened layer 8 'of the photosensitive resin defining the liquid path and the discharge port to form a liquid path and the like. Finally, an electrolytic solution (processing solution) containing an electrolyte is put into the liquid chamber and the liquid path, and anodic oxidation is performed again ((k)).
The anodized portion is not shown). In this way, the surface of the film which is not covered with the cured layer of the photosensitive resin is changed to an oxide to form a resistance heating element, and this oxide is used as a protective film. Complete the recording head.

In the case of the above description, it is preferable that the first anodic oxidation is performed by completely insulating the portion to be anodized, and the second anodization needs to leave a suitable conductivity in the anodized portion. Therefore, it is necessary to carry out each anodic oxidation correspondingly.

In the ink jet recording head completed as described above, the heating resistor and the electrode are formed using the same material as a starting material, but the heating resistor is essentially thinner than the other parts, that is, the electrodes. , The resistance value is large.

The anodic oxidation of the film 4 of the starting material in the above step will be described in more detail.

A case in which tantalum (Ta) is formed on a support as a starting material film will be specifically described.

Based on the steps (a) to (d) of FIG.
Using a support having a cured film of a photosensitive resin on the film as a treatment solution, a 1% by weight aqueous solution of phosphoric acid was used, and a current density of 10 mA / cm ² ,
Anodizing was performed for a processing time of 120 s. As a result, the Ta film in contact with the processing solution was almost completely oxidized in the thickness direction to become an insulator (FIG. 3E).

Next, after bonding the top plate of the recording head based on the steps (f) to (k) in FIG. 3, a 1% by weight aqueous phosphoric acid solution is supplied into the recording head, and a desired current density of 5 mA / cm ² is obtained. The surface portion of the Ta film was anodized so as to obtain the resistance value described above, thereby forming a portion serving as a resistance heating element (step (k) in FIG. 3).

When ink was supplied to the ink jet recording head thus manufactured and recording was actually performed, recording with extremely stable ejection characteristics could be performed.

In the above embodiment, if the width of the electrode can be made larger than the width of the heater, it is not necessary to anodize only the second heater region (the heater resistance can be made sufficiently larger than the electrode resistance).

Further, the shapes of the electrode region and the resistance heating portion region may be as shown in the schematic plan view of FIG. In FIG. 6, reference numeral 601 denotes an electrode area, and 602 denotes a resistance heating section area.

As shown in FIG. 4 (d), the pattern formed by the cured film of the photosensitive resin only needs to have a liquid path corresponding to the resistance heating portion. Therefore, a cured film of a photosensitive resin may be provided in the region 401 in FIG. 4 (d). FIG. 7 is a schematic plan view in which FIG. 4 (d) is partially enlarged.

In the above description, a recording head may be manufactured by preparing a substrate in which the electrode region and the resistance heating portion region are formed by anodic oxidation, and forming a liquid path and the like thereon.

Also, it is not always necessary to anodize between the heating resistor elements, and unnecessary portions are removed by etching, and the electrode region for forming the heating resistor element and the resistance heating section are anodized as required, thereby forming the heating resistor element. It may be formed.

[Effects of the Invention] As described above in detail, in the present invention, an ink jet recording head can be manufactured by two patterning steps and one film forming step, so that the number of steps can be significantly reduced. Further, according to the present invention, without using an etching step,
Patterning can be performed only by anodic oxidation, and in addition to the above-described reasons, the manufacturing time can be reduced. Further, according to the present invention, the installation position accuracy of each member is also improved.

In addition, according to the present invention, since there is little unevenness on the upper surface (the upper surface of the substrate) of the heating resistor element, it is possible to provide a recording head which is hardly peeled off from each member and has high durability.

It goes without saying that, within the scope of the present invention, the order of producing the recording heads and the configuration of the recording heads can be arbitrarily changed.

[Brief description of the drawings]

FIG. 1 is a view showing a preferred embodiment of an ink jet recording head, FIGS. 2 (a) to (q) are manufacturing process diagrams of a conventional ink jet recording head, and FIGS. 3 (a) to (k) are drawings of the present invention. FIG. 4 (a) is a plan view schematically showing a manufacturing process of the ink jet recording head, FIG. 4 (a) is a plan view showing a completed process of FIG. 3 (d), and FIG. 4 (b) is a process of FIG. 3 (e). 4 (c) is a plan view after the step of FIG. 3 (f) is completed, and FIG. 4 (d) is a plan view of a step after FIG. 3 (i) is completed. FIG. 5 is a sectional view of one embodiment of the ink jet recording head of the present invention (FIG. 7A-A ').
FIG. 6 is a plan view showing another example of the shapes of the electrode region and the resistance heating portion region, and FIG. 7 is a partially enlarged plan view of FIG. 4 (d). 1,101: discharge port, 2,102: liquid path 3,103: liquid chamber 4: film that can be a heating resistor or an electrode 4A, 104A: thermal energy generator 5,253: support, 6,257: top plate 7, 7 ': resist, 8, 256: Photosensitive resin 8 ': Cured layer of photosensitive resin 251,252: Layer (heating resistance layer) 301,401: Oxide 254,254', 254 ", 254: Photoresist 253: Protective film, 256 ': Wall 601: Electrode area, 602: Resistance heating area

Claims (19)

(57) [Claims] 1. An electric power source, comprising: a discharge port for discharging a liquid; a heating resistor; and an electrode for supplying a current to the heating resistor. An ink jet recording head comprising a heat converter and a support for supporting the electrothermal converter, wherein the support selectively anodizes a conductive material and completely insulates an anodized region. The conductive layer is provided so as to support the converted layer, and a predetermined portion of the conductive portion remaining uninsulated in the layer serves as an electrode, and the conductive portion partially covers the electrode region by the anodic oxidation. An ink jet recording head, wherein a portion having a higher resistance is a heating resistor. 2. An electric power source, comprising: a discharge port for discharging a liquid; a heating resistor; and an electrode for supplying a current to the heating resistor. An ink jet recording head comprising a heat converter and a support for supporting the electrothermal converter, wherein the support selectively anodizes a conductive material and completely insulates an anodized region. The electrode is provided so as to support the converted layer, a predetermined portion of the conductive portion remaining uninsulated in the layer is an electrode, and only the surface of the conductive portion is anodically oxidized to partially cover the electrode. An ink jet recording head, wherein a portion having a higher resistance than a region is a heating resistor portion. 3. The conductive material is Ta, V, Nb, Zr, M
3. The inkjet recording head according to claim 1, wherein the inkjet recording head is selected from the group consisting of g, Zn, Ni, Gd, and Co. 4. The ink jet recording head according to claim 1, further comprising a protective layer on at least a part of the electrothermal transducer. 5. An electric power source having a discharge port for discharging a liquid, a heating resistor portion, and an electrode for supplying a current to the heating resistor portion, for generating heat energy used for discharging the liquid. What is claimed is: 1. A method for manufacturing an ink jet recording head, comprising: a heat converter and a support for supporting the electrothermal converter, comprising: providing a conductive material on the support; and selecting the conductive material. A process of completely anodizing the region to be anodized to completely insulate the anodized region, wherein a predetermined portion of the conductive portion remaining uninsulated among the conductive materials serves as an electrode and A method of manufacturing an ink jet recording head, wherein a portion of the portion, the resistance of which is partially increased by the anodic oxidation as compared with the region of the electrode, is a heating resistor portion. 6. The conductive material is Ta, V, Nb, Zr, M
The method according to claim 5, wherein the method is selected from the group consisting of g, Zn, Ni, Gd, and Co. 7. The method according to claim 5, wherein the conductive material is formed by a vacuum deposition method. 8. The method according to claim 5, wherein the vacuum deposition method is a sputtering method or a vapor deposition method. 9. The method according to claim 5, wherein the anodic oxidation is selectively performed by using a resist provided on the conductive material layer. 10. The method according to claim 5, further comprising a protective layer on at least a part of the electrothermal transducer. 11. A method for manufacturing a substrate for a recording head having an electrothermal transducer for discharging liquid on a support, comprising: forming a layer of a conductive material on the support; And oxidizing at least a portion of the surface region of the remaining conductive portion to form an electrode and a heating resistor portion of the electrothermal converter. Manufacturing method of a recording head substrate. 12. The method according to claim 11, wherein the oxidation is anodic oxidation. 13. The material according to claim 1, wherein said material is Ta, V, Nb, Zr, Mg, Zn,
12. The method according to claim 11, wherein the substrate is selected from the group consisting of Ni, Gd, and Co. 14. The method according to claim 11, wherein the material is formed by a vacuum deposition method. 15. The method according to claim 14, wherein the vacuum deposition method is a sputtering method or a vapor deposition method. 16. The method according to claim 11, wherein the insulator is formed by using a photolithography process. 17. The method according to claim 11, wherein the formation of the at least a part of the surface region is performed using a photolithography process. 18. The method according to claim 11, further comprising providing a protective layer on at least a part of the electrothermal transducer. 19. A step of: (a) forming a film exhibiting conductivity and heat resistance and capable of being anodized on a support; and (b) anodizing the film other than a portion serving as an electrode and a heating resistor. (C) a step of laminating the photosensitive composition; and (d) a step of partially removing the photosensitive composition to form at least a discharge port and a wall member and to form a portion that becomes a low heat generation antibody. (E) bonding a top plate; and (f) oxidizing the exposed surface of the film by anodic oxidation to form a low-heat-antibody and leaving a film that is not anodized as an electrode. A method of manufacturing an ink jet recording head, comprising: