JPH08244229A - Board for ink jet recording head and oxidizing method for metal protective layer surface - Google Patents

Abstract

PURPOSE: To eliminate the treatment of waste ink in the manufacturing step, and to uniformly print with small density irregularity and stably in economy by forming a metal protective layer formed on the surface of a heater of a metal protective layer oxidized on its surface. CONSTITUTION: An ink jet recording head is formed by sequentially laminating an insulating layer, an electric insulation interlayer film, a heating layer made of tantalum nitride, an aluminum wiring layer, an electric insulation protective film, and a metal protective layer disposed at the uppermost part on a silicon substrate. A common liquid chamber 504 on a recording head board 100 of the laminated structure is formed of a top plate 502 and a channel wall member 501. A potential of about 20 to 50V is applied between a driving bonding pad 25 provided on the metal protective layer and recording liquid 24 in contact with the metal protective layer for about 0.1 to several seconds to oxidize the metal protective layer. Thus, the contaminant on the metal surface is removed, and the entire metal protective layer is cleaned.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording head substrate having a metal protective layer formed by oxidation on the surface of a heating element and a method for oxidizing the metal protective layer.

[0002]

2. Description of the Related Art In a recording apparatus such as a copying machine, a facsimile machine, a word processor, an output printer of a host computer, and a video output printer, heat is used to record on a recording medium such as paper. For example, in the case of an inkjet recording type recording apparatus, recording is performed by bubbling ink by heat according to a recording signal and ejecting / flying the ink from an ejection port by the energy of the bubbling. Heat is also used in recording on a thermal paper or recording by a thermal transfer method. In the case of recording using such heat, it is necessary to reduce the size of the heat source in order to increase the recording density, and the electrothermal conversion element that is the heat source is placed on the substrate such as silicon using photolithography technology. The aggregate is used. At this time, a recording functional element used for driving the electrothermal conversion element heater or the like may be integrally provided on the substrate.

Here, a substrate on which at least an electrothermal converting element is integrally formed is referred to as an ink jet recording head substrate (HB). The inkjet recording head substrate (HB) is a substrate such as silicon
This is a structure in which an electrically insulating interlayer film, an electrically resistive heating layer, an electrically insulating protective film, and a refractory metal film are formed in this order. For the interlayer film and the protective film, SiO ₂ , SiO, SiN, or a refractory metal such as Ta. W. Ti or the like is used, and HfB ₂ , TaxNy, or the like is used for the heat generating layer. In addition, a wiring layer made of aluminum or the like is provided to energize a predetermined portion of the heat generating layer to generate heat. The inkjet recording head is provided with a nozzle that forms an ink flow path for each heater and a common liquid chamber that supplies ink to each nozzle on the head substrate (HB).
An electrical connection for driving each heater and an ink tank for supplying ink to a common liquid chamber are attached to complete the process.

By supplying an electric signal required for ejection to each heater, ink is ejected from each nozzle by the energy of bubbles foamed on the heater and is printed on the recording paper. However,
In the completed ink jet recording head, the foaming surface (metal film surface) of the heater is contaminated due to various processes, and the foaming start voltage Vth tends to vary from heater to heater, resulting in unstable ejection. After the conventional ink jet recording head is completed, 5 with energy of about 1.3 to 1.35 Vth
Aging of ˜20 × 10 ⁴ pulses is performed to stabilize the ejection.

FIG. 5 is a flow chart showing an example of a conventional manufacturing / inspecting method of an ink jet recording head. The conventional manufacturing / inspection method will be described in more detail with reference to FIG. After forming a recording functional element on a substrate such as silicon, an interlayer SiO ₂ layer is formed by sputtering, then a heater material and a protective film layer are formed, and photolithography is provided to pattern into a predetermined pattern shape. Then, the head substrate (HB) is completed. Substrate for the head (HB)
Of the nozzle that is cut to separate the ink into a predetermined size, forms an ink flow path, an electrical connection for driving each heater and an ink tank etc, and forms the ink flow path for each heater. Is filled up with ink. After the ink is injected, each head is subjected to ejection aging for about 5 to 20 × 10 ⁴ pulses at an energy 1.3 to 1.35 times the foaming start voltage (Vht) of the head,
By stabilizing the foaming of each nozzle, the print quality is checked at the regular operation voltage = 1.2 Vth, and the non-defective product is packaged and shipped.

[0006]

However, the above-mentioned conventional example has the following problems. (1) Contamination of the refractory metal surface layer on the uppermost layer of the heater varies between the inkjet recording heads and between nozzles in the head, and the effect on foaming stability due to discharge aging varies and the print quality is stable. It may cause uneven density. (2) Contamination of the refractory metal surface layer of the uppermost layer can be removed only in the vicinity of the foamed portion of the heater upper layer, so that the stain begins to dissolve in the ink with time and deteriorates the printing quality. (3) Since it is performed using the recording ink etc liquid, a great deal of cost is required to process the discharged waste ink etc waste liquid.

Therefore, the present invention provides an ink jet recording head which does not require treatment of waste ink in the manufacturing process and is capable of uniform printing with little density unevenness and economically stable printing. Has an aim.

[0008]

In order to achieve the above object, the present invention is characterized in that, in an ink jet recording head substrate having a metal protective layer on the surface of a heating element, the surface of the metal protective layer is oxidized. To do. In the present invention, a refractory metal is used for the metal protective layer, a bonding pad capable of inputting an electric signal is provided on the surface thereof, and the electric signal is taken out through a metal wiring for driving the heating element. be able to. In addition, the method for oxidizing the surface of the metal protective layer laminated on the surface of the heating element of the substrate for an inkjet recording head of the present invention comprises oxidizing the surface of the metal protective layer by applying a potential between the surface of the metal protective layer and a liquid in contact therewith. The feature is that it is done. Then, it is more effective to oxidize the surface of the metal protective layer by an anodic oxidation method. Further, the electric potential is preferably about 20 to 50 V for about 0.1 second to several seconds.

[0009]

Since the present invention is constituted as described above, the metal protective layer on the surface of the heating element is oxidized by applying a predetermined potential to the surface to oxidize the surface of the protective layer on the surface of the heating element. Entirely cleaned, Vt between each heater
It is possible to obtain an ink jet recording head capable of high-quality recording with uniform h, stable foaming, and less density unevenness, and the conventional waste ink treatment associated with ejection aging in the manufacturing process is unnecessary. .

[0010]

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing the structure of a printhead substrate according to an embodiment of the present invention. This recording head substrate comprises a silicon substrate 10, an insulating layer 12 made of SiO ₂ or the like, an electrically insulating interlayer film 14, and tantalum nitride (T).
axNy) heat generating layer 15 and aluminum wiring layer 1
6, an electrically insulating protective film 17, and a protective layer 18 made of tantalum, which is located at the top, are sequentially laminated. A part of the aluminum wiring layer 16 is missing, and the heat generating layer 15 and the protective film 17 form an interface at this missing part, and this part becomes a heat generating part 20. Silicon substrate 1
At 0, the n-type semiconductor portion and the p-type semiconductor portion provided by a known silicon semiconductor process are mixed and the diode 11 is formed. The diode 11 is a recording functional element in the recording head substrate. In addition, a transistor as a driver and data retention. Of course, a shift register for transfer is also one of the recording functional elements. Through holes are provided in the insulating layer 12 at the anode electrode portion and the cathode electrode portion of the diode 11. An aluminum electrode layer 13 patterned in a predetermined shape is provided at the interface between the insulating layer 12 and the interlayer film 14. The aluminum electrode layer 13 is the insulating layer 1.
It is also formed inside the through hole provided in No. 2, so that an electrical connection between a predetermined portion of the silicon substrate 10 and the aluminum electrode layer 13 is secured. Through holes are formed in the interlayer film 14 so as to correspond to the aluminum electrode layers 13. As a result, the heat generating layer 15 formed on the interlayer film 14 is bonded to the aluminum electrode layer 12 at this through hole portion. An aluminum wiring layer 16 for energizing the heat generating layer 15 is formed on the heat generating layer 15. The heat generating layer 15 and the aluminum wiring layer 16 are each patterned into a predetermined shape, and the upper surface of the heat generating layer 15 is bonded only to the aluminum power distribution layer 16 except for the heat generating portion 20. Therefore, if a voltage is applied to the aluminum wiring layers 16 on both sides sandwiching the heat generating portion 20, the heat generating portion 2
The current concentrates on 0 and heat is generated.

The protective film 17 is provided on the entire surface (the upper surface in the figure) of the recording head substrate except for the portion where the aluminum wiring layer 16 and the outside are electrically connected.
The protective layer 18 is formed on the protective film 17. The protective layer 18 is connected to the heater driving aluminum wiring 16 through the through-hole portion 21 of the protective film 17,
It is configured such that a potential can be arbitrarily applied to 8. Furthermore, the ink jet recording head of the present invention is shown in FIG.
As shown in FIG. 5, the common liquid chamber 504 is composed of the top plate 502, the flow path wall member 501, and the like on the recording head substrate 100 having the above-described laminated structure. A potential of about 20 to 50 V is applied between the Ta film layer 18 and the liquid 24 in contact with the Ta film layer 18 for about 0.1 to several seconds to oxidize the surface of the Ta film layer to remove stains on the Ta surface. The entire surface layer was cleaned and Vth was evenly distributed between the heaters.
Further, it is possible to obtain an inkjet recording head capable of high-quality recording with stable foaming and less uneven density.

The manufacturing and inspection method of the present invention will be described in more detail with reference to FIG. After forming a recording functional element on a substrate such as silicon, an interlayer SiO ₂ layer is formed by sputtering, and then a heater material and a protective film layer are formed and patterned into a predetermined pattern shape using photolithography technology. Then, the head substrate (HB) is completed. The head substrate (HB) is cut in order to separate it into a predetermined size, a member to be an ink flow path, an electrical connection for driving each heater and an ink tank etc are assembled, and ink is attached to each heater. Ink is filled up to the tip of the nozzle that forms the ink flow path. After that, the surface of the Ta layer is oxidized as follows. Electrical connection is made by connecting the drive bonding pad 25 provided on the surface of the Ta layer shown in FIG. 3 (A) to the Ta layer as a positive electrode and the ink in the ink flow path as a negative electrode, and applying a potential of 20 to 50 V. Apply for 0.1 to several seconds, and
The surface of the a layer is oxidized to clean the Ta surface. afterwards,
The print quality is checked with a regular operation voltage (1.2 Vth), and non-defective products are packed and shipped.

As another embodiment of the present invention, as a method of oxidizing the surface of the Ta layer, the Ta layer is used as the negative electrode and the ink is used as the positive electrode, and the Ta layer is anodized after electrolytic degreasing by the method shown in the first embodiment. This makes the present invention more effective. Further, as a method of oxidizing the surface of the Ta layer, 300-4
It is possible to obtain substantially the same effect by leaving it for 30 to 60 minutes in the atmosphere of 00 ° C. Further, even if the ink jet head is completed after the surface oxidation of the Ta layer is carried out with the ink jet recording substrate alone, almost the same effect as that of the embodiment can be obtained.

Next, an ink jet recording apparatus using the recording head of the present invention will be described with reference to FIG. FIG. 4 shows an inkjet recording apparatus 700 to which the present invention is applied.
It is a general | schematic perspective view which shows an example. The recording head 510 is
A lead screw 70 that rotates via driving force transmission gears 702 and 703 in association with the forward and reverse rotations of the driving motor 701.
It is mounted on a carriage 720 that engages with the four spiral grooves 721, and is reciprocally moved in the directions of arrows a and b along a guide 719 together with the carriage 720 by the power of the drive motor 701. The recording paper P is conveyed onto the platen 706 by a recording medium feeding device (not shown). The paper pressing plate 705 provided so as to face the platen 706 presses the recording paper P against the platen 706 in the moving direction of the carriage 720. Photocouplers 707 and 708 are provided near one end of the lead screw 704. The photocapsules 707 and 708 are home position detecting means for confirming the presence of the lever 709 attached to the carriage 720 in this area and switching the rotation direction of the drive motor 701. A cap member 711 that caps the entire ejection surface of the recording head 510 when recording is stopped.
And the cap member 711 is a support member 710.
Supported by. Further, suction means 712 for sucking the inside of the cap member 711 is provided. Suction means 712
Is for performing suction recovery of the recording head 510 via the opening 713 in the cap. The main body support plate 716 supports a cleaning blade 714 and a moving member 715 that allows the cleaning blade 714 to move in the front-rear direction. Needless to say, the cleaning blade 714 is not limited to this type and a known cleaning blade can be applied to this embodiment. The lever 717 for starting suction for suction recovery moves in accordance with the movement of the cam 718 that engages with the carriage 720. The lever 717 controls the movement of the driving force from the driving motor 701 by a known transmission means such as clutch switching. A print control unit (not shown) that gives a signal to the heat generating unit 110 (FIG. 4) of the recording head 510 and controls the drive control of each mechanism described above is provided on the apparatus main body side.
The inkjet recording device 700 having the above-described configuration is
The recording head 510 performs recording on the recording paper P conveyed on the platen 706 while reciprocating over the entire width of the recording paper P. The recording head 510 is manufactured by the method described above. Therefore, high-accuracy and high-speed recording is possible. In the above description, an example in which the recording head substrate is used in an ink jet type recording head has been described. However, the recording head substrate according to the present invention can be applied to, for example, a thermal head substrate.

The present invention is particularly effective in an ink jet recording type recording head or recording apparatus for recording by forming flying droplets by utilizing thermal energy among the ink jet recording methods. For its typical structure and principle, see, for example, US Pat.
No. 129, the same is disclosed in the 4740796 specification,
The present invention is preferably carried out using these basic principles. This recording method can be applied to both the so-called on-demant type and the continuous type. To briefly explain this recording method, a nucleate boiling phenomenon occurs in the liquid (ink) corresponding to the recorded information in the electrothermal converter arranged corresponding to the sheet or liquid path holding the liquid (ink). By applying at least one drive signal for providing a rapid temperature rise that causes a film boiling phenomenon, thermal energy is generated and film boiling occurs on the heat acting surface of the recording head. As described above, bubbles can be formed in one-to-one correspondence with the drive signal applied from the liquid (ink) to the electrothermal converter, which is particularly effective for the on-demant recording method. The liquid (ink) is ejected through the ejection holes by the growth and contraction of the bubbles to form at least one droplet. It is more preferable to make this drive signal into a pulse shape because bubbles can be immediately and appropriately grown and contracted, so that liquid (ink) ejection with excellent responsiveness can be achieved. As the pulse-shaped drive signal, those described in US Pat. Nos. 4,463,359 and 4,345,262 are suitable. If the conditions described in US Pat. No. 4,313,124, which is an invention relating to the rate of temperature rise on the heat acting surface, are adopted, more excellent recording can be performed. As the configuration of the recording head, in addition to the configuration in which the ejection holes, the liquid flow paths, and the electrothermal converters as disclosed in the above-mentioned specifications are combined (straight liquid flow path or right-angled liquid flow path), U.S. Pat.No. 4558333, U.S. Pat.No. 4459600
As disclosed in the specification, the present invention also includes a structure in which the heat acting portion is arranged in the bending region.
In addition, Japanese Patent Laid-Open No. 123670/1984 discloses a configuration in which a common slit is used as a discharge hole of the electrothermal converter for a plurality of electrothermal converters, and an opening for absorbing a pressure wave of thermal energy. Japanese Unexamined Patent Application Publication No. Sho 5 (1998)
The present invention is also effective in a configuration based on Japanese Patent No. 138461.

Further, as a recording head to which the present invention is effectively used, there is a full line type recording head having a length corresponding to the maximum width of a recording medium which can be recorded by a recording device. The full line head may be a full line configuration formed by combining a plurality of print heads as disclosed in the above specification, or may be a single full line print head integrally formed. in addition,
When mounted on the main body of the device, a replaceable chip-type recording head that enables electrical connection to the main body of the device and supply of ink from the main body of the device, or a cover provided integrally with the recording head itself. The present invention is also effective when a recording head of the ridge type is used. Further, it is preferable to add recovery means for the recording head, preliminary auxiliary means, etc. to the recording apparatus of the present invention because the recording apparatus of the present invention can be made more stable. Specific examples thereof include capping means, cleaning means, pressurizing or suctioning means, electrothermal conversion or a heating element other than this for the recording head, or preheating means by means of a combination thereof, recording and It is also effective to perform stable recording by adding a means for performing a preliminary ejection mode for performing another ejection. Further, the recording mode of the recording apparatus is not limited to the mode in which only the mainstream color such as black is recorded, but may be one in which the recording head is integrally configured or a combination of a plurality of recording heads, which are different. The present invention is also extremely effective for an apparatus provided with at least one of a multicolored color or a full color by color mixing.

[0017]

As described above, according to the present invention, by oxidizing the surface of the metal protective layer on the surface of the heating element, the entire heater surface layer contaminated during the manufacturing process is cleaned and all the heaters are cleaned. It is possible to perform good printing with uniform foaming, less density unevenness, and economically stable. Further, in the assembling process in manufacturing, it is not necessary to treat the waste ink accompanying the discharge aging as in the conventional case, and it is possible to greatly reduce the cost.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing the configuration of a printhead substrate according to an embodiment of the present invention.

FIG. 2 is a flow chart showing an example of a method of manufacturing the recording head substrate of FIG.

FIG. 3 is a schematic perspective view showing the outer appearance of an inkjet recording head according to an embodiment of the present invention.

FIG. 4 is a perspective view showing an example of an inkjet recording apparatus.

FIG. 5 is a flowchart showing an example of a conventional method for manufacturing a recording head substrate.

[Explanation of symbols]

 10 Silicon Substrate 11 Diode 12 Insulating Layer 13 Aluminum Electrode Layer 14 Interlayer Film 15 Exothermic Layer 16 Aluminum Wiring Layer 17 Protective Film 18 Protective Layer 20 Exothermic Part 24 Recording Liquid (Ink) 25 Driving Bonding Pad 26 Support 27 PCB 100 Substrate for print head 500 Discharge port 501 Liquid path wall member 502 Top plate 503 Ink supply port 504 Common liquid chamber 505 Liquid path 700 Inkjet recording device 701 Drive motor 704 Lead screw 705 Paper holding plate 706 Platen 720 Carriage

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Hiroshi Sugitani 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Makiko Kimura 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Within the corporation

Claims (7)

[Claims] 1. A substrate for an inkjet recording head having a metal protective layer on the surface of a heating element, wherein the metal protective layer is composed of a metal protective layer whose surface is oxidized. . 2. The substrate for an ink jet recording head according to claim 1, wherein the metal protective layer is made of a refractory metal. 3. The ink jet recording head substrate according to claim 1, wherein the metal protective layer is provided with a bonding pad capable of inputting an electric signal. 4. The substrate for an ink jet recording head according to claim 3, wherein the bonding pad is configured to be taken out via a metal wiring that drives a heating element. 5. A method for oxidizing a surface of a metal protective layer laminated on a surface of a heating element of a substrate for an ink jet recording head, wherein the surface of the metal protective layer is oxidized by applying a potential between the surface of the metal protective layer and a liquid in contact therewith. A method for oxidizing the surface of a metal protective layer of a substrate for an ink jet recording head, which is characterized by being performed. 6. The method for oxidizing the surface of a metal protective layer of an ink jet recording head substrate according to claim 5, wherein the surface of the metal protective layer is oxidized by an anodic oxidation method. 7. The method for oxidizing the surface of a metal protective layer of a substrate for an ink jet recording head according to claim 5, wherein the electric potential is set to about 20 to 50 V for about 0.1 second to several seconds. .