JP2007055007A - Inkjet recording head and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet recording head or the like capable of decreasing deviation of the delivering direction and generation of non-delivering phenomenon caused by piling up of ink generated on an ink delivering face. <P>SOLUTION: The inkjet recording head has a plurality of ink delivering holes 1, ink flow paths 6 respectively communicated with the ink delivering holes 1, and ink delivering energy generating elements 7 arranged in respective ink flow paths 6. A plurality of rows of delivering holes made by arranging a plurality of the ink delivering holes 1 in lines on the ink delivering face on which the ink delivering holes 1 are opened. Channels 2 extending in the lengthwise direction of the rows of the delivering holes are formed between a plurality of the rows of the delivering holes on the ink delivering face, and an acute angle is formed by the wall face of the channel 2 and the ink delivering face. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an ink jet recording head that performs recording by ejecting ink to form flying droplets and a method for manufacturing the same. The present invention relates to a printer that performs recording on a recording medium such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, ceramics, a facsimile having a communication system, and various processing devices. The present invention can be applied to a combined industrial recording apparatus.

  In this specification, “recording” means not only giving an image having a meaning such as a character or a figure to a recording medium but also giving an image having no meaning such as a pattern. .

  An ink jet recording head applied to an ink jet recording method (liquid jet recording method) generally includes a plurality of fine recording liquid discharge ports, a flow path, and a plurality of recording liquid discharge energy generating elements provided in a part of the flow path. As methods for forming recording liquid discharge ports and flow paths with high density and high accuracy, methods disclosed in Patent Document 1 and Patent Document 2 are known.

  Even when the high quality of the recorded image is realized by using the ink jet recording head thus manufactured, there are some problems that the ejection of the ink droplets becomes unstable. One example is wetness near the ink discharge port.

  One cause of wetting is the presence of ultra-fine ink droplets called mist. The mist is generated along with the main ink droplets at the time of ink droplet ejection, and is considered to adhere to the ink ejection surface where the ink ejection ports are formed and form an ink reservoir. Conventionally, in an ink jet recording apparatus, ink droplets adhering to an ink ejection surface are wiped off by a wiper formed of an elastic material such as rubber. Usually, the ink discharge surface is subjected to water repellent treatment, and ink droplets around the ink discharge port can be removed by such a wiper operation.

  However, by repeating the wiper operation as described above, the water repellency of the water repellent member applied to the ink ejection surface is deteriorated, and the water repellent member is scraped or peeled off. When the wiper operation is repeated in this state, the mists adhering to the ink ejection surface are combined with each other and gradually become larger and grow into an ink reservoir. If this ink reservoir grows further and connects to the ink in the ink discharge port and closes the ink discharge port, the ink droplets discharged from the ink discharge port may be twisted or the ink droplets may be discharged from the ink discharge port. An undischarge phenomenon that is not discharged occurs.

As means for avoiding such a phenomenon, Patent Document 3 proposes forming a groove in the adjacent ink flow path outer wall portion of the same ink discharge port array. According to this configuration, the mist adhering to the periphery of the ejection port escapes into the groove formed so as to be dug in the surface of the outer wall of the ink flow path by the wiper operation, and does not remain attached to the periphery of the ejection port. Therefore, it is difficult for ink to accumulate on the ink ejection surface, and it is possible to prevent the occurrence of misalignment in the ejection direction and undischarge phenomenon.
JP-A-5-330066 JP-A-6-286149 JP 2002-211985 A

  However, in order to further suppress the occurrence of ink pools on the ink discharge surface, in order to efficiently release the mist adhering to the ink discharge surface to the groove, a wider groove is located as close as possible to the ink discharge port array. It is preferable to provide in. In addition, it is preferable to have a structure that can prevent ink that has once escaped into the groove from reattaching to the ink ejection surface during the wiper operation.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an ink jet recording head capable of reducing the occurrence of a deviation in the ejection direction and an undischarge phenomenon caused by an ink pool generated on an ink ejection surface, and a method for manufacturing the same.

  In order to achieve the above object, an ink jet recording head according to the present invention includes a plurality of ink discharge ports for discharging ink, an ink flow path communicating with each of the ink discharge ports, and disposed in each of the ink flow paths. An ink discharge energy generating element for applying energy for discharging ink from the ink discharge port to the ink in the ink flow path, and the plurality of ink discharge ports on an ink discharge surface where the ink discharge port is open. In the inkjet recording head in which a plurality of ejection port arrays in which outlets are arranged are arranged side by side, a groove extending in the length direction of the ejection port array between the plurality of ejection port arrays on the ink ejection surface And the wall surface of the groove and the ink discharge surface form an acute angle.

  According to the present invention, since the groove provided between the ink ejection port arrays has a reversing shape in which the wall surface of the groove and the ink ejection surface form an acute angle, the ink once escaped into the groove Is prevented from reattaching to the ink ejection surface during the wiper operation. As a result, it is possible to reduce the occurrence of misalignment in the ejection direction and undischarge phenomenon due to the ink pool generated on the ink ejection surface.

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

(First embodiment)
In the present embodiment, an ink jet recording head having a structure in which a groove is provided between the ink discharge port arrays arranged via the ink supply port was manufactured. In the present embodiment, the angle formed by the ink discharge surface and the side surface of the groove is different from the angle formed by the ink discharge surface and the ink discharge port.

  FIG. 1 is a diagram for explaining a method of manufacturing an ink jet recording head according to the first embodiment of the present invention.

  First, as shown in FIG. 1A, the material of the mold material 9 (ODUR, manufactured by Tokyo Ohka Kogyo Co., Ltd.) was applied to a thickness of 14 μm on the Si substrate 4 provided with the ink discharge energy generating element 7. Furthermore, the mold material 9 was patterned by performing the exposure and development. This mold material 9 forms a space which becomes a foaming chamber and a flow path in a state where the nozzle portion is completed.

  Next, as shown in FIG. 1B, the nozzle forming member 3a was applied on the substrate 4 to a thickness of 14 μm by spin coating. As the material of the nozzle forming member 3a, a material prepared by dissolving an epoxy resin and a cationic photopolymerization initiator in a solvent was used. Then, it heated at 100 degreeC and the nozzle formation member 3a was hardened.

  Subsequently, as shown in FIG. 1C, the nozzle forming member 3b was applied by spin coating to a thickness of 11 μm on the substrate 4 on which the mold material 9 and the nozzle forming member 3a were patterned to a thickness of 14 μm. As the material for the nozzle forming member 3b, a material prepared by dissolving an epoxy resin and a cationic photopolymerization initiator in a solvent was used in the same manner as described above.

  Subsequently, as shown in FIG. 1 (d), a water repellent member 8 having a thickness of 0.5 μm was formed on the nozzle forming member 3b by laminating a dry film. As the material of the water repellent member 8, a material prepared by dissolving an epoxy resin and a photocationic polymerization initiator in a solvent was used.

  Subsequently, as shown in FIG. 1E, exposure of the nozzle forming members 3a and 3b and the water repellent member 8 is performed using a mirror projection mask aligner (MPA-600 Super, manufactured by Canon Inc.). Went. In this step, a portion to be a groove provided between the ink discharge port arrays arranged via the ink supply port is patterned.

The nozzle forming members 3a and 3b and the water repellent member 8 were exposed by irradiating 0.2 J / cm ² of UV light 12 through a mask 10a. At this time, the regions of the nozzle forming members 3a and 3b and the water repellent member 8 that have been irradiated with the UV light 12 are in a state where the crosslinking reaction has started and hardened, and the region that has not been irradiated with the UV light 12 blocked by the Cr pattern 13a It remains in a state where it can be removed with an organic solvent without causing a crosslinking reaction. Note that the mirror projection mask aligner is focused so that the image of the Cr pattern 13a formed on the mask 10a is in focus at the position of 14 μm in height from the surface of the substrate 4, that is, the surface of the mold material 9. Like so).

Further, as shown in FIG. 1 (f), using another mask 10b, the nozzle forming members 3a and 3b and the water repellent member 8 are again irradiated with 0.2 J / cm ² of UV light 12 and their nozzles 3a and 3b are re-irradiated. Exposure was performed. In this step, a portion that becomes an ink discharge port is patterned. In this process, the same mirror projection mask aligner as described above is used. The mirror projection mask aligner is set so that the image of the Cr pattern 13b formed on the mask 10b is focused at a position 25 μm high from the surface of the substrate 4, that is, the surface of the nozzle forming member 3b. . The focal position was changed from the previous step by moving the trapezoidal mirror that constitutes the mirror, projection, and mask aligner.

  Further, as shown in FIG. 1 (g), the regions of the nozzle forming members 3a and 3b and the water repellent member 8 that have not been irradiated with the UV light 12 are removed with a developer and then heated at 100 ° C. 1 and groove 2 were formed. In the present embodiment, the angle formed between the wall surface of the ink discharge port 1 and the ink discharge surface is approximately 90 °, whereas the angle formed between the wall surface of the groove 2 and the ink discharge surface is approximately 80 °. This angle difference is provided by exposing the nozzle forming members 3a and 3b and the water repellent member 8 by changing the position where the mask image in the thickness direction of the nozzle forming members 3a and 3b is focused.

  Subsequently, Si was etched by immersing the Si substrate 4 on which the mold material 9, the nozzle forming members 3a and 3b and the water repellent member 8 were patterned in a TMAH 22 wt% aqueous solution heated to about 80 ° C. for ten hours. The ink supply port 5 was formed in the Si substrate 4 (see FIG. 2).

  Finally, the mold material 9 was eluted from the ink discharge port 1 and the ink supply port 5 using a solvent to form the ink flow path and the foaming chamber 6 (see FIG. 2), and the nozzle portion of the ink jet recording head was formed. . Further, the substrate 4 on which the nozzle portion is formed is separated, cut and chipped by a dicing saw, and electrical connection of wiring (not shown) for driving the ink discharge energy generating element 7 is performed, and then ink is supplied. The chip tank member (not shown) was connected to complete the ink jet recording head.

  Using this ink jet recording head, the print quality and the state of the ink ejection surface when a print durability test was conducted with pigment ink were confirmed. At this time, the wiper operation was performed periodically. At the initial printing stage (1000 printed sheets), the printing quality was good, and no twisting or undischarge occurred. The state of the ink ejection surface at this time is shown in FIG. On the ink ejection surface, mist generated along with ink droplet ejection and ink droplets 11 formed by combining the mists adhered to each other. However, the number of occurrences was small and the size was relatively small.

  Furthermore, a printing durability test was conducted, and even when the number of printed sheets was 30,000, the printing quality was good, and no twisting or undischarge occurred. The state of the ink ejection surface at this time is shown in FIG. Mist and ink droplets 11 adhered to the ink ejection surface, but the number of occurrences was still relatively small. The presence of ink was also confirmed in the groove 2. This is considered that the mist and the ink droplet 11 adhering to the ink discharge surface flowed in the wiper operation.

  Furthermore, a printing endurance test was conducted, and even when the number of printed sheets was 100,000, no twisting or undischarge occurred. The state of the ink ejection surface at this time is shown in FIG. Although the number and size of the mist and ink droplets 11 adhering to the ink ejection surface are gradually increasing, they were not at a level to block the ink ejection port 1. It was also confirmed that the amount of ink flowing into the groove 2 was increased compared to the time when the number of printed sheets was 30,000.

  Furthermore, a printing endurance test was conducted, and when the number of printed sheets was 200,000, twisting and undischarge occurred. At this time, an ink pool that is in contact with or blocking the ink discharge port 1 is generated on the ink discharge surface. Inferring from the state of occurrence of ink pool, it is considered that the ink once flowing into the groove 2 gradually increases as the number of printed sheets increases and reattaches to the ink ejection surface during the wiper operation.

  As described above, the structure in which the groove 2 is provided on the ink discharge surface is effective as a evacuation place for mist and ink droplets adhering to the ink discharge surface, and does not cause twisting or non-discharge even when the number of printed sheets increases. It is effective as a countermeasure. In order to prevent twisting and non-discharge even when more printing is performed, it is necessary to prevent reattachment of ink once flowing into the groove 2 to the ink ejection surface. For this purpose, it is considered effective to further reduce the angle formed by the side surface of the groove 2 and the ink discharge surface to make a structure like a flip.

(Second Embodiment)
In the present embodiment, an ink jet recording head having a structure in which the angle formed by the side surface of the groove and the ink discharge surface is smaller than that in the first embodiment is manufactured.

  FIG. 4 is a diagram for explaining a method of manufacturing an ink jet recording head according to the second embodiment of the present invention. The manufacturing method of the ink jet recording head of this embodiment has the same steps as those of the first embodiment and is substantially the same. However, in the step shown in FIG. 4E, the nozzle forming member 3b is patterned so that the angle formed by the side surface of the groove and the ink discharge surface is smaller than that in the first embodiment. In the present embodiment, the angle formed between the wall surface of the ink discharge port 1 and the ink discharge surface is approximately 90 °, whereas the angle formed between the wall surface of the groove 2 and the ink discharge surface is approximately 70 °.

  Using this ink jet recording head, the print quality and the state of the ink ejection surface when a print durability test was conducted with pigment ink were confirmed. At this time, the wiper operation was performed periodically. At the initial printing stage (1000 printed sheets), the printing quality was good, and no twisting or undischarge occurred. The state of the ink ejection surface at this time is shown in FIG. On the ink ejection surface, mist generated along with ink droplet ejection and ink droplets 11 formed by combining the mists adhered to each other. However, the number of occurrences was small and the size was relatively small.

  Further, a printing endurance test was performed. Even when the number of printed sheets was 30,000, no twisting or non-discharge occurred, and as shown in FIG. 5B, mist and ink droplets 11 adhered to the ink ejection surface. The number of occurrences was still relatively small, and the presence of ink in the groove 2 was confirmed.

  Further, a printing endurance test was conducted, and no twist or undischarge occurred even when the number of printed sheets was 200,000. The state of the ink ejection surface at this time is shown in FIG. Although the number and size of the mist and ink droplets 11 adhering to the ink ejection surface are gradually increasing, they are not at a level that blocks the ink ejection port 1 and the occurrence of ink accumulation was not confirmed.

  As described above, when the angle formed between the wall surface of the groove 2 and the ink discharge surface is made smaller and turned upside down, the ink once flowing into the groove 2 is reattached to the ink discharge surface to form an ink reservoir. It was confirmed that it is effective in preventing the generation.

(Third embodiment)
In the present embodiment, an ink jet recording head having a structure in which the entire surface of the ink ejection surface including the side surface and bottom portion of the groove is subjected to water repellency treatment was produced. FIG. 6 is a diagram for explaining a method of manufacturing an ink jet recording head according to the third embodiment of the present invention.

  First, as shown in FIG. 6A, the material of the mold material 9 (ODUR, manufactured by Tokyo Ohka Kogyo Co., Ltd.) was applied to a thickness of 14 μm on the Si substrate 4 provided with the ink discharge energy generating element 7. Furthermore, the mold material 9 was patterned by performing the exposure and development. This mold material 9 forms a space which becomes a foaming chamber and a flow path in a state where the nozzle portion is completed.

  Next, as shown in FIG. 6B, the nozzle forming member 3a was applied on the substrate 4 to a thickness of 14 μm by spin coating. As the material of the nozzle forming member 3a, a material prepared by dissolving an epoxy resin and a cationic photopolymerization initiator in a solvent was used. Then, it heated at 100 degreeC and the nozzle formation member 3a was hardened.

  Subsequently, as shown in FIG. 6C, the nozzle forming member 3b was applied by spin coating to a thickness of 11 μm on the substrate 4 on which the mold material 9 and the nozzle forming member 3a were patterned to a thickness of 14 μm. As the material for the nozzle forming member 3b, a material prepared by dissolving an epoxy resin and a cationic photopolymerization initiator in a solvent was used in the same manner as described above.

  Subsequently, as shown in FIG. 6D, the nozzle forming members 3a and 3b were exposed using a mirror projection mask aligner (MPA-600 Super, manufactured by Canon Inc.). In this step, a portion to be a groove provided between the ink discharge port arrays arranged via the ink supply port is patterned.

The nozzle forming members 3a and 3b were exposed by irradiating 0.2 J / cm ² of UV light 12 through the mask 10a. At this time, the region where the UV light 12 of the nozzle forming members 3a and 3b is irradiated is in a state where the crosslinking reaction is started and hardened, and the region where the UV light 12 is blocked by the Cr pattern 13a and is not irradiated does not undergo the crosslinking reaction and is organic. The solvent remains removable. The mirror projection mask aligner is set so that the image of the Cr pattern 13a formed on the mask 10a is focused (focused) on the surface of the substrate 4, that is, the bottom surface of the mold material 9. is there.

Furthermore, as shown in FIG. 6 (e), the nozzle forming members 3a and 3b were again irradiated with 0.2 J / cm ² of UV light 12 using another mask 10b to expose them. In this step, a portion that becomes an ink discharge port is patterned. In this process, the same mirror projection mask aligner as described above is used. The mirror projection mask aligner is set so that the image of the Cr pattern 13b formed on the mask 10b is focused at a position 25 μm high from the surface of the substrate 4, that is, the surface of the nozzle forming member 3b. . The focal position was changed from the previous step by moving the trapezoidal mirror that constitutes the mirror, projection, and mask aligner.

  Further, as shown in FIG. 6 (f), the regions of the nozzle forming members 3a and 3b that were not irradiated with the UV light 12 were removed with a developer.

Further, as shown in FIG. 6G, a water repellent member 8 having a thickness of 0.5 μm was formed on the ink discharge surface by spin coating. As the material of the water repellent member 8, a material prepared by dissolving an epoxy resin and a photocationic polymerization initiator in a solvent was used. Subsequently, exposure was performed by irradiating the water-repellent member 8 with 0.2 J / cm ² of UV light using the mask 10 c provided with the Cr pattern 13 only at the position corresponding to the ink discharge port 1. In this process, the same mirror projection mask aligner as described above is used. In the mirror projection mask aligner, the image of the Cr pattern 13c formed on the mask 10c is focused at a position 25 μm in height from the surface of the substrate 4, that is, the surface of the nozzle forming member 3b (the bottom surface of the water repellent member 8). Is set to tie. The focal position was changed from the previous step by moving the trapezoidal mirror that constitutes the mirror, projection, and mask aligner.

  Thereafter, as shown in FIG. 6 (h), the ink discharge port 1 and the groove 2 are formed by removing the region of the water repellent member 8 that has not been irradiated with the UV light with a developer and heating at 100 ° C. did. In the present embodiment, the angle formed between the wall surface of the ink discharge port 1 and the ink discharge surface is approximately 90 °, whereas the angle formed between the wall surface of the groove 2 and the ink discharge surface is approximately 70 °.

  Subsequently, Si was etched by immersing the Si substrate 4 on which the mold material 9, the nozzle forming members 3a and 3b and the water repellent member 8 were patterned in a TMAH 22 wt% aqueous solution heated to about 80 ° C. for ten hours. The ink supply port 5 was formed in the Si substrate 4 (see FIG. 2).

  Finally, the mold material 9 was eluted from the ink discharge port 1 and the ink supply port 5 using a solvent, thereby forming the ink flow path and the foaming chamber, and forming the nozzle portion of the ink jet recording head. Further, the substrate 4 on which the nozzle portion was formed was separated, cut, and chipped by a dicing saw, and wiring (not shown) for driving the ink discharge energy generating element 7 was electrically joined. Thereafter, a chip tank member (not shown) for supplying ink was connected to complete the ink jet recording head.

  Using this ink jet recording head, the print quality and the state of the ink ejection surface when a print durability test was conducted with pigment ink were confirmed. At this time, the wiper operation was performed periodically. At the initial printing stage (1000 printed sheets), the printing quality was good, and no twisting or undischarge occurred. Also, the number of mists and ink droplets adhering to the ink ejection surface was small and the size was relatively small.

  Further, a printing endurance test was conducted, and no twist or undischarge occurred even when the number of printed sheets was 200,000. Although the number and size of mist and ink droplets adhering to the ink ejection surface are gradually increasing, it is not at a level that blocks the ink ejection port, and no occurrence of ink accumulation has been confirmed. In addition, although it was confirmed that ink was present in the groove 2, the ink that once flowed into the groove 2 continues to be held in the groove 2, and the ink in the groove 2 reattaches to the ink ejection surface. Such a phenomenon was not confirmed.

  As described above, when the groove 2 has a reverse structure and the entire surface of the ink discharge surface including the side and bottom of the groove 2 is subjected to water repellency, the ink once flowing into the groove 2 It has been confirmed that it is effective to keep it.

It is a figure explaining the manufacturing method of the inkjet recording head which concerns on the 1st Embodiment of this invention. 1A is a top perspective view of the ink jet recording head manufactured by the manufacturing method shown in FIG. 1, and FIG. 2B is a cross-sectional view taken along the line A-A ′. It is a figure which shows the state of the ink discharge surface when a printing durability test is performed with the pigment ink using the inkjet recording head produced by the manufacturing method shown in FIG. It is a figure explaining the manufacturing method of the inkjet recording head which concerns on the 2nd Embodiment of this invention. It is a figure which shows the state of the ink discharge surface when a printing durability test is performed with the pigment ink using the inkjet recording head produced by the manufacturing method shown in FIG. It is a figure explaining the manufacturing method of the inkjet recording head which concerns on the 3rd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ink discharge port 2 Groove 4 Si substrate 6 Ink flow path and foaming chamber 7 Ink discharge energy generating element

Claims (8)

A plurality of ink discharge ports for discharging ink, ink flow paths communicating with the respective ink discharge ports, and energy disposed in each of the ink flow paths for discharging ink from the ink discharge ports; An ink discharge energy generating element applied to the ink of
In an ink jet recording head in which a plurality of ejection port arrays in which the plurality of ink ejection ports are arranged are arranged side by side on an ink ejection surface where the ink ejection ports are open,
A groove extending in the length direction of the ejection port array is formed between the plurality of ejection port arrays on the ink ejection surface, and a wall surface of the groove and the ink ejection surface form an acute angle. An ink jet recording head.   The ink jet recording head according to claim 1, wherein a water repellent treatment is performed on the ink ejection surface excluding a wall surface and a bottom surface of the groove.   The ink jet recording head according to claim 1, wherein a water repellent treatment is performed on the ink ejection surface including a wall surface and a bottom surface of the groove. Forming a mold material that occupies at least a portion serving as an ink flow path on a substrate provided with a plurality of ink discharge energy generating elements that generate energy for discharging ink; and
Forming a nozzle forming member on the substrate and the mold material;
Forming a plurality of ink discharge ports such that a plurality of discharge port arrays in which a plurality of ink discharge ports are arranged are arranged side by side on the nozzle forming member;
Removing the mold material;
In the manufacturing method of the inkjet recording head having
The grooves extending in the length direction of the ejection port array, the plurality of ejection port arrays on the ink ejection surface such that the wall surface of the groove and the ink ejection surface where the ink ejection port is opened form an acute angle. A method of manufacturing an ink jet recording head, further comprising a step of forming between them.   The method of manufacturing an ink jet recording head according to claim 4, further comprising a step of performing water repellency treatment on the ink ejection surface excluding the wall surface and bottom surface of the groove.   The method of manufacturing an ink jet recording head according to claim 4, further comprising a step of performing water repellency treatment on the ink discharge surface including the wall surface and the bottom surface of the groove. The nozzle forming member is made of a photosensitive resin material,
Forming the plurality of ink discharge ports on the nozzle forming member includes projecting a mask image forming the plurality of ink discharge ports to expose the nozzle forming member;
The step of forming the groove between the plurality of ejection port arrays on the ink ejection surface includes the step of forming the nozzle forming member in which the mask image forming the groove focuses the mask image forming the plurality of ink ejection ports. 7. The method according to claim 4, further comprising exposing the nozzle forming member by projecting a mask image forming the groove so as to focus at a position different from the position in the thickness direction. A method for manufacturing an inkjet recording head.   8. The method of manufacturing an ink jet recording head according to claim 4, wherein the mold material is made of a soluble resin material, and the step of removing the mold material includes eluting the mold material with a solvent. .

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