JP2005161711A - Inkjet recording head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet recording head that performs highly precise printing at a high speed and has a structure preventing the head from being increased in the cost and the size. <P>SOLUTION: This inkjet recording head is equipped with a chip tank 11 and a chip 12 is provided on the chip tank 11. The chip 12 consists of a single chip. Two rows of ink ejection nozzle groups are disposed on the chip 12 by each of colors of black, cyan, magenta and yellow. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an ink jet recording head for generating recording droplets used in an ink jet recording system.

  In particular, the present invention relates to a so-called “side shooter type” ink jet recording head that ejects ink droplets in a direction substantially perpendicular to a main surface of a substrate on which an ink ejection energy generating element for generating ink ejection energy is formed. .

  The ink jet recording system is extremely small in noise generation at the time of recording, can be recorded at high speed, can be fixed on so-called plain paper, and can be recorded without special processing. In that respect, it has been spreading rapidly in recent years.

  Ink jet recording heads, which are components that eject recording droplets by such an ink jet recording method, include so-called “edge shooter type” and “side shooter type” depending on the head configuration. The “edge shooter type” means that ink droplets are ejected in a direction substantially parallel to the main surface of the substrate on which the ink ejection energy generating element for generating ink ejection energy is formed.

  As one of the parameters for controlling the amount of ink discharged droplets, the center of the ink discharge energy generation element corresponding to the ink discharge energy generation element from the center of the ink discharge energy generation element on the main surface of the substrate via the flow path Distance (hereinafter referred to as OH distance). That is, the size of the ejected droplet is generally determined by the OH distance. Also, compared to the “edge shooter type”, the “side shooter type” can easily manage the OH distance by the film thickness formed on the main surface of the substrate, so a small liquid of 10 picoliters or less for high-definition printing. It is suitable for a liquid discharge head that discharges droplets.

  Furthermore, in the ink jet recording heads described in Patent Document 1, Patent Document 2, and Patent Document 3, bubbles generated by heating a heating resistor disposed in a flow path communicating with the discharge port are discharged from the discharge port to the outside air. And an ink droplet is ejected. Since the techniques described in these documents can always maintain a constant discharge amount of ink droplets, even if high-definition recording is performed with small droplets, the printing unevenness and the like are very small. Printing results can be obtained.

  On the other hand, in recent years, it has been known that a means for recording while modulating the ejection amount of ink droplets is effective in order to obtain a higher-speed printing and photographic image quality recording result.

  As a specific example, for the purpose of achieving high-speed recording, a nozzle that discharges a larger amount of liquid droplets than when high-definition printing is performed is required. Furthermore, when trying to obtain more photographic image quality output, it is possible to obtain smooth recording results with less graininess by modulating the ejection amount even for ink droplets of the same color. Become.

  In order to satisfy this requirement, it is necessary to prepare a plurality of chips for ejecting ink droplets of the same color but with different ejection amounts.

FIG. 7 shows two such chips that eject ink droplets of the same color and different ejection amounts for each ink color of Bk (black), C (cyan), M (magenta), and Y (yellow). An example of the configuration is shown. In this configuration example, in the case of yellow ink, a chip 25 and a chip 26 having nozzles (ink discharge ports) that discharge ink droplets of different discharge amounts are laid out. When preparing chips for ejecting ink droplets having different ejection amounts from the nozzles of the four colors, a total of eight chips 19 to 26 are placed on the chip tank 11, that is, in the same recording head. I have prepared it. Here, the chip tank 11 is an ink introduction component for introducing the color ink discharged from each chip into each chip from the ink storage unit of each color.
Japanese Patent Laid-Open No. 4-10940 JP-A-4-10941 JP-A-4-10942

  However, the configuration shown in FIG. 7 requires alignment between the chips in order to lay out the chips 19 to 26 at the correct positions in the same recording head. For this reason, the higher the quality of printing, the higher the alignment accuracy. On the other hand, there is a problem that the cost and size of the recording head must be avoided.

  The present invention has been made in view of the above-described problems of the prior art, and is an inkjet recording head for performing high-speed and high-definition printing, and an inkjet having a configuration that does not increase the cost and size of the inkjet recording head. An object is to provide a recording head.

  In order to achieve the above object, the present invention provides a liquid ejection head that ejects liquid droplets substantially perpendicularly to a substrate surface on which energy generating means for generating liquid droplet ejection energy is formed. There are two rows of discharge port groups in which a plurality of discharge ports are arranged. From the center of the discharge port of the droplets in the first row, the energy generating means corresponding to the discharge ports via the flow path is provided. A chip in which a distance to the center and a distance from the center of the ejection port of the droplet in the second row to the center of the energy generating means corresponding to the ejection port via a flow path are different It is characterized by that. With this configuration, it is possible to vary the amount of liquid droplets discharged from each of the first row droplet discharge ports and the second row droplet discharge ports in the same chip. In addition, since two types of droplet discharge port arrays are provided on one chip in order to discharge droplets of different sizes, alignment between the liquid discharge port arrays becomes unnecessary, and one column is arranged on one chip. Compared with the conventional example in which the liquid droplet ejection openings are provided, the management of alignment accuracy corresponding to higher definition of printing is eased.

  In the above liquid discharge head, a substrate surface on which a plurality of the energy generating means are formed and a discharge port surface on which a plurality of droplet discharge ports are formed corresponding to each of the energy generating means are parallel to each other. It is preferable.

  Further, the energy generating means corresponding to the droplet discharge ports of the first row is located on a line orthogonal to the substrate surface through the center of the droplet discharge ports of the second row. The energy generating means corresponding to the droplet ejection ports in the second row is separated from a line orthogonal to the substrate surface through the center of the droplet ejection ports in the second row. Preferably it is in position.

  Furthermore, the droplet discharge ports in the second row are formed at positions farther from the liquid supply port to the flow path than the droplet discharge ports in the first row. preferable.

  The liquid droplet discharge ports in the first row and the liquid droplet discharge ports in the second row share a single liquid supply port to the flow path. It is preferred that a single color liquid is supplied.

  Further, the chip supplies only one color liquid from the liquid supply port to the flow path, and one color is supplied from the droplet discharge port of the first row and the droplet discharge port of the second row. It may be a liquid discharge head configured to discharge only droplets and provided with two or more corresponding to two or more colors.

  Further, the chip is provided with two or more liquid supply ports to the flow path so as to supply liquids of two or more colors, and the droplet discharge ports in the first row and the second row The liquid droplet ejection heads may be configured such that two or more groups of the liquid droplet ejection ports are configured to eject liquid droplets of different colors, and the chip is single or plural.

  In the liquid discharge head as described above, the droplet discharge ports in the first row and the droplet discharge ports in the second row are different in size.

  According to the present invention, the amount of liquid compared to the conventional example in which one discharge port array is provided for each chip by providing two discharge port arrays with different droplet amounts for each color or for a plurality of colors in one chip. Alignment between two discharge port arrays having different values becomes unnecessary. As a result, an increase in the cost of the liquid discharge head can be avoided. Furthermore, since two discharge port arrays having different liquid amounts are provided in one chip, the liquid discharge head is not increased in size.

  In addition, by having two discharge ports that discharge different amounts of droplets of the same color, recording can be performed while modulating the droplet discharge amount, so that high-quality photographic image quality can be achieved simultaneously with high-speed printing. A print record can also be obtained.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic view of an opening surface of an ejection port in an ink jet recording head according to an embodiment of the present invention as viewed from above, and FIG. 2 shows a part of the A-A ′ cross section of FIG. FIG. 3 is a schematic perspective view of the A-A ′ cross section of FIG. 1. FIG. 2 shows a B-B ′ cross section of FIG. 3.

  As shown in FIG. 1, the ink jet recording head of this embodiment includes a chip tank 11, and a chip 12 is disposed on the chip tank 11. The chip 12 is composed of one chip, and two rows of ink discharge port groups are arranged on the chip for each color of black, cyan, magenta, and yellow. Each row of ink ejection groups has a configuration in which a plurality of ink ejection ports 5 and 6 are arranged on a straight line.

  Of the ink discharge ports 5 and 6 formed on the chip 12, the ink discharge port 5 is an opening (nozzle portion) that discharges a small droplet and the ink discharge port 6 is a large droplet.

  The chip tank 11 is an ink introduction component for introducing the ink discharged from each ink discharge port into each color ink discharge port 5, 6 from each color ink tank (not shown).

  In the liquid discharge head of the form shown in FIG. 1, four ink supply ports 7 are provided in one chip 12 so as to supply four colors of liquid, and the first row of ink discharge ports 5 and 2 are provided. Four sets of ink discharge ports 6 in this row are provided so as to discharge droplets of four colors.

  2 and 3, the chip 12 has a structure in which the resin layer 4 that forms the flow path 8 is provided on the substrate 2, and the ink discharge ports 5 and 6 that are connected to the flow path 8 are formed in the resin layer 4. is there. A communication path connecting the ink discharge ports 5 and 6 and the flow path 8 is a nozzle.

  The heating resistors 1 and 2 are disposed on the surface of the substrate 3 in contact with the flow path 8. The flow path 8 can supply ink through an ink supply port 7 formed in the substrate 3.

  The opening surface of the resin layer 4 where the ink discharge ports 5 and 6 are opened and the surface of the substrate 3 on which the heating resistors 1 and 2 are disposed are parallel, and the entire opening surface where the ink discharge ports 5 and 6 are opened. The distance between the opening surface of the ink discharge port and the arrangement surface of the heating resistor is the same.

  As shown in FIG. 2, the heating resistor 1 is arranged on a line that passes through the center of the ink discharge port 5 and is orthogonal to the main surface of the substrate 3. For this reason, the distance (OH distance) connected through the center of the flow path from the center of the heating resistor on the main surface of the substrate 3 to the center of the ink discharge port on the opening surface of the ink discharge port is the distance X. X is equal to the distance from the main surface of the substrate 3 to the opening surface of the ink discharge port 5. On the other hand, the heating resistor 2 is arranged on a line that is separated from the center of the ink discharge port 6 and orthogonal to the main surface of the substrate 3. For this reason, the OH distance is a distance Y longer than the distance X.

  With such a configuration, the nozzle corresponding to the ink discharge port 5 discharges an ink droplet of a relatively small discharge amount (for example, 1 to 3 picoliters), and the nozzle corresponding to the ink discharge port 6 is relatively A large discharge amount (for example, 5 to 10 picoliters) of ink droplets can be discharged.

  FIG. 4 is a schematic view of the opening surface of the discharge port in an ink jet recording head according to another embodiment of the present invention as seen from above.

  In the ink jet recording head shown in FIG. 4, two chips 13 and 14 are arranged on the chip tank 11. The chip 13 is for black. On the chip 13, ink discharge port groups for discharging black ink are arranged in two rows. Further, the chip 14 is for color, and on the chip 14, ink ejection port groups are arranged in two rows for each color of cyan, magenta, and yellow.

  In the black chip 13, two types of ink ejection port groups with different ejection amounts are arranged in the same chip. On the other hand, in the color chip 14, by arranging two types of ink ejection port groups having different ejection amounts for each color of C, M, and Y in the same chip, intercolor alignment between the color nozzles is unnecessary. . Further, the ink discharge port of the black chip 13 is formed larger than the ink discharge port of the color chip 14.

  As described above, in the liquid discharge head of the form shown in FIG. 4, one black chip 12 is provided with one ink supply port 7 for supplying black ink, and the first row of ink discharge ports 5 and One set of ink discharge ports 6 in the second row is provided so as to discharge black ink droplets. Further, one color chip 14 has ink supply ports 7 of three colors (C, M, Y). Three sets are provided to supply ink, and a set of ink discharge ports 5 in the first row and ink discharge ports 6 in the second row discharges ink droplets of three colors (C, M, Y). A set is provided.

  In the form of FIG. 4, for the purpose of high-speed recording, only the black nozzle is a separate chip from the color nozzle.

  FIG. 5 is a schematic view of the opening surface of the ejection port in an ink jet recording head according to still another embodiment of the present invention as viewed from above.

  In the ink jet recording head shown in FIG. 5, on the chip tank 11, a black (Bk) nozzle chip 15, a cyan (C) nozzle chip 16, a magenta (M) nozzle chip 17, and a yellow (Y) nozzle. A total of 4 chips 18 for use are arranged. In this case, since a chip is prepared for each color, it is not necessary to align the ink ejection port groups of each color when forming a plurality of rows of ink ejection port groups in each color chip.

  At the beginning of production of a new ink jet recording head, the yield may be relatively low, and the production yield may be disadvantageous because of the larger number of ink discharge ports per chip. In such a case, as shown in FIG. 5, a reduction in production yield may be suppressed by disposing chips for each color separately.

  As shown in FIG. 5, the present invention is different from the example shown in FIGS. 1 and 4 in that each of the four chips 15 to 18 corresponds to four colors (Bk, C, M, Y). A liquid discharge head configured to supply liquid of only one color from one ink supply port 7 and discharge ink droplets of only one color from the ink discharge port 5 in the first row and the ink discharge port 6 in the second row. It may be.

  Next, a method for manufacturing the ink jet recording head of this embodiment will be described. 6A to 6D are process diagrams for explaining an example of the method of manufacturing the ink jet recording head of the present invention, and FIG. 6E is the same cross-sectional view as FIG. Here, for the convenience of explanation, a method for manufacturing a part for discharging a certain color will be described.

  First, as shown in FIG. 6A, the resin layer 9 that can be dissolved in the substrate 3 provided with the heating resistors 1 and 2 that generate thermal energy for ink ejection is used by photolithography, etching, or the like. The ink channel pattern having a rectangular cross section is formed by a known method. At this time, as shown in FIG. 6A, the ink flow path pattern is asymmetrically arranged with respect to the center line of the heating resistors 1 and 2.

  Next, as shown in FIG. 6B, the resin layer 4 is formed on the ink flow path pattern made of the soluble resin layer 9 so as to cover the ink flow path pattern. Here, the resin used for the resin layer 4 has photosensitivity and has the property of not being compatible with the soluble resin layer 9.

  Next, a pattern to be the ink discharge port 5 is formed in a corresponding portion of the resin layer 9 vertically above the heating resistor 1 by ultraviolet rays or Deep-UV, and the heating resistor 2 of the resin layer 9 is further formed. A pattern to be the ink discharge port 6 is formed in a portion away from the heating resistor 1 with respect to the reference.

  Subsequently, as shown in FIG. 6D, an ink supply port 7 that is an opening for supplying ink to the flow path is formed between the heating resistors 1 and 2 of the substrate 3. The ink supply port 7 may be formed by any method as long as it is a method of making a hole in the substrate 3, and drilling, sandblasting, or the like is used. Preferably, the anisotropy of the Si substrate by an alkaline solution is used. By etching, it can be formed with high accuracy.

  Further, as shown in FIG. 6 (e), the soluble resin layer 9 is eluted and removed, whereby the flow path 8 connecting the ink discharge ports 5 and 6 from the ink supply port 7 is completed.

  Finally, electrical joining for driving the heating resistors 1 and 2 is performed on the chip (reference numeral 12 in FIG. 1) completed by the above-described steps (not shown). Furthermore, the chip is joined to a chip tank (reference numeral 11 in FIG. 1) in a predetermined arrangement, and ink of a predetermined color is introduced into an ink supply port of each color of the chip from an ink tank (not shown), thereby performing ink jet recording. The head is completed.

  In the ink jet recording head manufactured as described above, the ink discharge ports formed in the same chip are formed with the alignment accuracy of photolithography, so that the relative position accuracy is excellent.

  As shown in FIG. 2, the completed inkjet recording head chip has a distance X from the heating resistor 1 to the ink discharge port 5 and a distance from the heating resistor 2 to the ink discharge port 6 as the OH distance. Y is different. Therefore, it is possible to obtain a recording head having nozzles (ejection ports) that can eject ink droplets of different sizes in the same chip, and this recording head enables high-speed and ultrahigh-definition recording.

  Such a configuration is particularly optimal for the ink jet recording heads described in Patent Documents 1, 2, and 3 (see, for example, Patent Documents 1, 2, and 3). In each patent document, a driving signal corresponding to recording information is applied to a heating resistor (electrothermal conversion element) to generate thermal energy that gives the electrothermal conversion element a rapid temperature rise exceeding the nucleate boiling of ink. A method is described in which bubbles are formed in the ink and the ink droplets are ejected by communicating the bubbles with the outside air. If the above-described configuration is further applied to a recording head using this method, several types of ejection amounts can be obtained. Ink droplets can be ejected. In addition, the volume and speed of the ink droplets can be stabilized, and a high-quality image can be obtained.

  In addition, the configuration and the manufacturing method of the recording head described above are also effective for a full-line type recording head capable of recording simultaneously over the entire width of the recording medium such as paper or film in the direction intersecting the conveying direction. .

  Further, the present invention will be described in more detail with reference to examples.

  In this example, an ink jet recording head was prepared according to the procedure shown in FIGS.

  First, Si is used for the material of the substrate 3, tantalum nitride is used for the heating resistors 1 and 2, polymethylisopropenyl ketone (ODUR-1010A, manufactured by Tokyo Ohka Kogyo Co., Ltd.) is used for the resin layer 4, and Deep. -An ink flow path pattern composed of the resin layer 9 was formed using UV exposure. At this time, the height of the ink flow path pattern is 13 μm.

  Next, the resin layer 4 having the composition shown in Table 1 was coated on the ink flow path pattern made of the resin layer 9 by spin coating.

  Next, a circular pattern serving as the ink discharge port 5 is formed in the corresponding portion of the resin layer 4 in the vertical upper direction of the heating resistor 1 by an exposure method using ultraviolet rays, and the heating resistor of the resin layer 4 is further formed. A circular pattern serving as the ink discharge ports 6 is formed in a portion away from the heating resistor 1 with reference to 2.

  For exposure, an exposure apparatus MPA-600 Super manufactured by Canon Inc. was used. Further, PEB (Post Exposure Bake), CDS-630 manufactured by Canon Inc. was used for development, and a mixed solution of methyl isobutyl ketone and xylene was used for the developer. The OH distance at this time is such that the distance X on the ink ejection port 5 side in FIG. 2 is 25 μm and the distance Y on the ink ejection port 6 side is 70 μm.

  Next, an ink supply port 7, which is an opening for supplying ink to the flow path 8, is formed in the Si substrate 3 by anisotropic etching using TMAH.

  Next, after the Deep-UV light is irradiated on the entire surface of the substrate, the substrate is immersed in methyl lactate, treated in an ultrasonic cleaning tank for about 2 hours to remove the resin layer 9, and then washed with pure water for about 10 minutes and dried. As a result, the flow path 8 is formed.

  In the chip thus obtained, nozzles having two different types of OH distances are formed, and ink droplets having two different types of discharge amounts are selectively discharged and printed onto a recording medium. Thus, it is possible to perform high-speed printing and super-quality printing without graininess.

FIG. 4 is a schematic view of an ink ejection port surface as viewed from above in the ink jet recording head according to the embodiment of the present invention. FIG. 2 is a cross-sectional view taken along line A-A ′ shown in FIG. 1. FIG. 2 is a schematic perspective view illustrating a part of a recording head cut along a cross section taken along line A-A ′ of FIG. 1. It is the schematic diagram which looked at the ink discharge port surface from the top about the inkjet recording head by another embodiment of this invention. It is the schematic diagram which looked at the ink discharge port surface from the top about the inkjet recording head by another embodiment of this invention. It is process drawing for demonstrating the basic manufacturing method of the inkjet recording head of this invention. It is the schematic diagram which looked at the ink discharge port surface from the top about the conventional inkjet recording head.

Explanation of symbols

1, 2 Heating resistor 3 Substrate 4 Resin layer 5, 6 Ink discharge port 7 Ink supply port 8 Channel 9 Resin layer 11 Chip tank 12, 13, 14, 15, 16, 17, 18 Chip

Claims (8)

In a liquid ejection head that ejects liquid droplets substantially perpendicularly to a substrate surface on which energy generating means for generating liquid droplet ejection energy is formed,
There are two rows of discharge port groups in which a plurality of the discharge ports of the droplets are arranged, and from the center of the discharge ports of the droplets in the first row, the discharge ports correspond to the discharge ports through a flow path. The distance to the center of the energy generating means is different from the distance from the center of the discharge outlet of the droplets in the second row to the center of the energy generating means corresponding to the discharge outlet via the flow path. A liquid discharge head comprising the chip.   2. The substrate surface according to claim 1, wherein the substrate surface on which a plurality of the energy generation means are formed and the discharge port surface on which the plurality of droplet discharge ports are formed corresponding to each of the energy generation units are parallel to each other. Liquid discharge head. The energy generating means corresponding to the droplet ejection ports in the first row is located on a line orthogonal to the substrate surface through the center of the droplet ejection ports in the second row;
A position where the energy generating means corresponding to the droplet ejection port in the second row is separated from a line orthogonal to the substrate surface through the center of the droplet ejection port in the second row The liquid discharge head according to claim 1 or 2, wherein   4. The droplet discharge port of the second row is formed at a position farther from the liquid supply port to the channel than the droplet discharge port of the first row. The liquid discharge head described in 1.   The liquid droplet discharge ports in the first row and the liquid droplet discharge ports in the second row share a single liquid supply port to the flow path. The liquid discharge head according to claim 1, wherein a single color liquid is supplied.   The chip supplies only one color liquid from the liquid supply port to the flow path, and only one color is supplied from the droplet discharge port of the first row and the droplet discharge port of the second row. The liquid discharge head according to claim 1, wherein the liquid discharge head is configured to discharge droplets and is provided with two or more corresponding to two or more colors.   In the chip, two or more liquid supply ports to the flow path are provided so as to supply liquids of two or more colors, and the droplet discharge ports in the first row and the liquid in the second row The liquid discharge head according to claim 1, wherein two or more sets of droplet discharge ports are provided so as to discharge droplets of different colors, and the chip is provided in a single or plural number. .   8. The liquid discharge head according to claim 1, wherein the droplet discharge ports of the first row and the droplet discharge ports of the second row have different sizes.

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