JP2014040021A - Recording head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a recording head which reduces a size of the recording head to the utmost while keeping stable filling property of a sealing material around a recording element substrate in a recording head having a structure in which the recording element substrates are arranged in parallel.SOLUTION: The recording head includes a plurality of recording element substrates discharging an ink droplet, and grooves for coating a sealing material provided at both outer sides of the recording element substrate group in which the plurality of recording element substrates are arranged in parallel. A periphery of the recording element substrate is sealed by a sealing material containing filler whose linear expansion coefficient after hardening is 40(×10/°C) or lower. In addition, a clearance dimension between recording element substrates satisfies a following relationship: "maximum outside dimension of filler×15<clearance dimension between recording element substrates<sealing groove width×2".

Description

  The present invention relates to a recording head used in an ink jet recording apparatus that performs recording on a recording medium by discharging ink. Specifically, the present invention relates to a recording head having a configuration in which a plurality of recording element substrates that eject ink are arranged in parallel.

  Conventionally, a recording head includes a recording element substrate that ejects ink droplets. For example, when ejecting ink droplets of different colors, the recording head includes a plurality of recording element substrates.

  Patent Document 1 discloses a recording head including a plurality of recording element substrates. As shown in FIG. 7, a plurality of recording element substrates 1 a that eject ink droplets constitute a recording element unit 6 a together with the wiring substrate 4 a, and the plurality of recording element units are fixed to the support member 7. In addition, the recording element substrate is individually sealed with a sealing resin 11 with respect to each support member 7.

  Patent Document 2 discloses a recording head having a configuration in which a plurality of recording element substrates are arranged adjacent to each other. As shown in FIG. 8, a plurality of ejection parts 52 are fixed adjacent to each other.

Japanese Patent Laid-Open No. 10-44412 JP 2002-248746 A

  However, in Patent Document 1, the recording head size is increased because the interval between the plurality of recording element substrates is large.

  In the case of a serial scan type recording apparatus in which the recording head scans and records, if the spacing between the recording element substrates is large, the recording head size in the recording head scanning direction increases and the recording time per scan increases. As a result, the recording time becomes longer.

  Further, in the case of a system in which the recording head performs recording without scanning, if the interval between the recording element substrates is long, the recording head size in the recording medium feeding direction becomes large. In that case, the area for holding the recording medium on a flat surface or a curved surface for accurately landing the ejected ink on the recording medium is increased. This deteriorates the accuracy of the surface to be held, the distance between the recording head and the recording medium becomes unstable, and the quality of the recorded image is lowered.

  Therefore, in a recording head having a configuration in which a plurality of recording element substrates are arranged adjacent to each other as in Patent Document 2, the size of the recording head can be reduced.

  By the way, if there is a gap around the recording element substrate, the ink that has entered the gap thickens, and it becomes easy to adsorb dust and the like, which may lead to a reduction in image quality. Therefore, it is necessary to fill the gap with a sealing material or the like. However, if the linear expansion coefficient after curing of the sealing material is large, the recording element substrate is damaged due to stress when the recording head receives a thermal shock. There is a fear.

  Here, the linear expansion coefficient value of the sealing material needs to be as close as possible to the linear expansion coefficient value of the recording element substrate. In order to keep the linear expansion coefficient of the sealing material low, a method of adding a filler or the like is effective. However, when the filler is added, the fluidity of the sealing material before curing is lowered, and it becomes difficult to fill the sealing material in the gaps between the recording element substrates.

  Accordingly, an object of the present invention is to provide a recording head in which the size of the recording head is kept as small as possible while maintaining the stable filling of the sealing material around the recording element substrate of the recording head configured to arrange the recording element substrates in parallel. The object is to provide a head.

  The present invention that achieves the above object includes a plurality of recording element substrates that eject ink droplets, and sealing material application grooves provided on both outer sides of a recording element substrate group in which the plurality of recording element substrates are arranged in parallel. Prepare.

The periphery of the recording element substrate is sealed with a filler containing a filler having a linear expansion coefficient of 40 (× 10 ⁻⁵ / ° C.) or less.

  Furthermore, the gap between the recording element substrates satisfies the following relationship.

    “Maximum outer shape of filler × 15 <Gap size between recording element substrates <Sealing groove width × 2”

  According to the above configuration, the periphery of the recording element substrate can be stably sealed, and the gap between the recording element substrates can be reduced as much as possible.

  By narrowing the gap between the recording element substrates, the scan time can be shortened in the case of a serial scan type recording apparatus, so that the recording time can be shortened.

  Further, in the case of a recording apparatus that performs recording without scanning by the recording head, the accuracy of the surface on which the recording medium should be held can be improved. That is, since the distance from the recording head to the recording medium can be managed with higher accuracy, the distance between the recording head and the recording medium is shortened, and the image quality is improved.

1 is a perspective view of an ink jet recording apparatus on which a recording head of the present invention is mounted. FIG. 2 is a side sectional view of the recording head shown in FIG. 1. FIG. 2 is a perspective view seen from the ejection hole side of the recording head shown in FIG. 1. FIG. 3 is a schematic diagram viewed from the recording medium side of the recording head illustrated in FIG. 2. FIG. 5 is a schematic diagram of a cross section QQ of the recording head illustrated in FIG. 4. FIG. 5 is a schematic diagram for explaining a gap size around the recording element substrate shown in FIG. 4. 6 is an external view showing a configuration of a recording head disclosed in Patent Document 1. FIG. FIG. 6 is an external view showing a configuration of a recording head of Patent Document 2.

  Embodiments of the present invention will be described below in detail with reference to the drawings.

  FIG. 1 is a perspective view showing a schematic configuration of an ink jet recording apparatus according to an embodiment of the present invention.

  The ink jet recording apparatus shown in FIG. 1 repeats the reciprocation (main scanning) of the recording head 201 and the conveyance (sub scanning) of the non-recording medium S at a predetermined pitch, and synchronizes with these movements. From which ink is selectively ejected. This is a serial scan type recording apparatus that forms characters, images, and the like by adhering the ejected ink to the recording medium S.

  In FIG. 1, a recording head 201 is detachably mounted on a carriage 202 that is slidably supported by two guide rails and is reciprocated on a straight line along a guide rail by a driving means such as a motor (not shown). ing. The non-recording medium S that receives the ink ejected from the ink ejection section of the recording head 201 faces the ink ejection surface of the recording head 201 by the conveyance roller 203 as a conveyance means, and maintains a constant distance from the ink ejection surface. Is done. Then, the recording medium S is conveyed in a direction intersecting with the moving direction of the carriage 202 (for example, an arrow A direction which is an orthogonal direction).

  The recording head 201 has a plurality of nozzle rows for ejecting different colors of ink as ink ejection units. A plurality of independent main tanks 204 are detachably attached to the ink supply unit 205 corresponding to the color of ink ejected from the recording head 201. The ink supply unit 205 and the recording head 201 are connected by a plurality of ink supply tubes 206 corresponding to the ink colors. By attaching the main tank 204 to the ink supply unit 205, it is possible to independently supply each color ink stored in the main tank 204 to each nozzle row of the recording head 201.

  A recovery unit 207 is disposed so as to face the ink ejection surface of the recording head 201 in a non-recording area that is within the reciprocating range of the recording head 201 and outside the passing range of the non-recording medium S. Yes. The recovery unit 207 has a cap portion (not shown) for capping the ink ejection surface of the recording head 201. Further, the recovery unit 207 has a suction mechanism (not shown) for forcibly sucking ink from the recording head 201 in a state where the ink discharge port surface is capped, a cleaning blade for wiping off dirt on the ink discharge surface, and the like. . The suction operation described above is performed by the recovery unit 207 prior to the recording operation of the ink jet recording apparatus.

  FIG. 2 is a side sectional view of the recording head 201 shown in FIG.

  In FIG. 2, the shape of the recording head 201 of the present embodiment is composed of approximately six surfaces of an upper surface 40, a lower surface 41, a front surface 42, a rear surface 43, a right side surface and a left side surface, and is integrally formed except for the upper surface 40 side. Has been. The recording head 201 can eject four colors of ink. That is, the ink of each color is separated from the main tank 204 (FIG. 1) from the needle (not shown) for each color by the partition wall (not shown) via the needle receiving portion 23 for each color. It is configured to be supplied into each sub tank 36. The ink supplied to the sub tank 36 is temporarily stored in the ink reservoir 21 through the filter 5 for removing impurities (foreign matter) in the ink and filtering the ink. Then, the ink flows into the ink supply liquid chamber 20 through the communication portion 37 and the flow path 6. The ink that has flowed into the ink supply liquid chamber 20 is ejected by the foaming energy generated by the electrothermal converter (not shown) that converts the electrical energy supplied from the heater board 26 provided on the lower surface 41 into thermal energy. It is discharged from the figure. The heater board 26 is provided with a plurality of ink discharge portions each composed of a nozzle row corresponding to each color ink, that is, corresponding to each sub tank 36, and the tip of each nozzle serves as a discharge hole. 26 is open on the surface.

  FIG. 3 is a perspective view of the recording head 201 as viewed obliquely from the ejection hole direction. Four recording element substrates having 1280 ejection holes are mounted. Among them, three recording element substrates that discharge Y, M, and C inks are arranged in parallel, and the recording element substrates are arranged with a slight gap therebetween. Further, a single recording element substrate for discharging Bk ink is disposed alone.

  FIG. 4 is a schematic view of the recording head 201 viewed from the recording medium on which the ejected ink is landed.

  In FIG. 4, a recording element substrate 28a is a recording element substrate that discharges color ink, and a recording element substrate 28b is a recording element substrate that discharges Bk ink. Both the recording element substrates 28a and 28b are provided with electrothermal transducers (not shown), and ink is foamed and discharged by electric energy. Electrical energy is supplied to the recording element substrate from an electrode (not shown) extending from the TAB 30. In order to protect the electrode portion from corrosion of ink or the like, it is sealed with an electrode seal 34.

  If there is a groove around the recording element substrates 28a and 28b, the ink enters there and thickens with time. When the thickened ink adsorbs dust or the like and the dust moves to the vicinity of the ejection hole, it affects the ejection direction of the ejected ink droplets, which may lead to degradation of image quality. Therefore, by sealing the grooves around the recording element substrates 28a and 28b, the concave shape can be eliminated as much as possible, and the amount of ink entering can be minimized. The recording element substrate is sealed all around by a peripheral sealing 35.

  FIG. 5 is a schematic diagram showing a cross section QQ in FIG.

  In FIG. 5, the recording element substrate 28 a is accurately positioned and bonded and fixed to the base plate 40. The supply port 41 provided in the base plate 40 and the ink introduction port 29 provided in the recording element substrate 28a communicate with each other, and the ink supplied from the ink supply liquid chamber 20 (FIG. 2) is supplied to the recording element substrate. .

  Further, in order to facilitate the electrode connection of the TAB 30 described above, the upper surface of the recording element substrate and the upper surface of the TAB 30 need to have the same height. Therefore, the cover plate 45 has substantially the same height as the recording element substrate 28a, and is positioned and bonded and fixed to the base plate 40. The TAB 30 is accurately positioned on the upper surface of the cover plate 45 and bonded and fixed.

By the way, in this embodiment, in order to avoid the influence of distortion or the like accompanying the temperature change on the recording element substrate 28a as much as possible, the linear expansion coefficient of the members constituting the periphery of the recording element substrate 28a is set to a value close to that of the recording element substrate 28a. Yes. The recording element substrate 28a is made of Si, and the linear expansion integer is approximately 3 (× 10 ⁻⁶ / ° C.). The base plate 40 and the cover plate 45 are made of alumina and are about 7 (× 10 ⁻⁶ / ° C.). The peripheral seal 35 is poured into a highly viscous liquid material and heated to cure. Since fluidity is required, it is necessary to use a resin, and therefore the linear expansion coefficient cannot be kept very low. By adding a filler or the like to the surrounding sealing material 36 (not shown), the linear expansion coefficient can be suppressed to some extent. In this example, a sealing material having a physical property after curing of about 30 (× 10 ⁻⁶ / ° C.) is used.

  FIG. 6 is a schematic diagram showing the recording element substrate 28a in FIG.

  In FIG. 6, the TAB 30 and the electrode seal 34 are not shown for explanation. Here, the peripheral seal 35 drops the liquid sealant 36 onto the seal groove 32 from the tip of the needle, and with time, the sealant 36 (not shown) is placed on the entire circumference of the recording element substrate 28a. Go around. Accordingly, the sealing groove width B needs to be a little larger than the needle diameter.

  By the way, when the sealing groove width B is increased, the peripheral sealing 35 may shrink on the low temperature side during thermal shock, and the recording element substrate 28a may be pulled and damaged. Therefore, the sealing groove width B needs to be as narrow as possible without hindering the dropping of the sealing material 36 with the needle. In this embodiment, the sealing groove has a width of 2.2 mm.

  Here, in order to reduce the recording head size, the gap width C between the recording element substrate 28a and the recording element substrate 28a is reduced. For the reason described above, in the case of the sealing material 36 to which the filler is added, the sealing material 36 is difficult to go around the gap 48.

  As a result of experiments, the present inventor has noticed that there is a certain correlation between the gap width C through which the sealing material to which the filler is added and the filler enter. In many cases, a spherical filler is added as a filler, but it has been found that the following relationship must be satisfied in order for the sealing material to wrap around stably.

Diameter of spherical filler x 15 <gap width C
In the present embodiment, since a spherical filler having a diameter of about 7 μm is added to the sealing material 36, the gap width C is set to 110 μm. With the configuration of this size, the sealing material can be stably wrapped around.

By the way, as described above, when the gap width C is increased, the recording head size is increased. In addition, the recording head may be damaged if the following relationship is not satisfied.
Gap width C <Sealing groove width B × 2
This is because, as described above, the sealing groove width B is designed so that the recording element substrate 28a is not damaged even by thermal shock. Therefore, if this dimension is exceeded, the recording element substrate 28a is similarly damaged by thermal shock. There is a fear. Since the peripheral seal 35 filled in the gap 48 pulls the recording element substrates 28a on both sides adjacent to each other at a low temperature due to thermal shock, the half of the gap width C should not exceed the seal groove width B. Become.

Therefore, when the relationship that the width of the gap 48 should satisfy is summarized, the following relationship is obtained.
Diameter of spherical filler × 15 <gap width C <sealing groove width B × 2
In this example, a sealing material containing a spherical filler having a diameter of 7 μm was used. The gap width between the recording element substrates is 110 μm, and the sealing groove width is 1.8 mm.

  Further, in this embodiment, the filler added to the sealing material is described as a spherical filler, but the relationship is the same even if it is a rod-shaped filler, and the maximum outer dimension of the rod-shaped filler is the diameter of the spherical filler. Has the same meaning. Therefore, in the case of a rod-shaped filler, the relationship to be satisfied is as follows.

Maximum external dimensions of rod-shaped filler × 15 <gap spacing <width W of sealing groove 32 × 2
For example, the maximum external dimension of the rod-shaped filler is 20.6 μm if the filler has a diameter of 10 μm and a length of 18 μm. Furthermore, if the filler has a diameter of 20 μm and a length of 12 μm, the maximum outer dimension is 23.3 μm.

  As described above, the interval between the recording element substrates arranged in parallel has been described. However, if the gap satisfies the above relationship, the periphery of the chip can be stably sealed, and the gap between the recording element substrates is narrowed. be able to.

  By narrowing the gap between the recording element substrates, the scan time can be shortened in the case of a serial scan type recording apparatus, so that the recording time can be shortened.

  Further, in the case of a recording apparatus that performs recording without scanning by the recording head, the accuracy of the surface on which the recording medium should be held can be improved. That is, since the distance from the recording head to the recording medium can be managed with higher accuracy, the distance between the recording head and the recording medium is shortened, and the image quality is improved.

  Further, in this embodiment, a description has been given of a bubble jet (registered trademark) type recording head that heats and foams ink, but the same effect can be obtained with an ink jet type recording head. Therefore, a piezo-type recording head that converts electrical energy into pressure may be used.

28a, 28b Recording element substrate 30 TAB
32 Sealing groove 35 Surrounding sealing 36 Surrounding sealing material 40 Base plate 48 Gap 201 Recording head B Sealing groove width C Gap width

Claims (3)

A recording element substrate for ejecting ink droplets;
A sealing material application groove provided outside the recording element substrate group in which a plurality of recording element substrates are arranged in parallel;
A sealing material containing a filler that seals the periphery of the recording element substrate and has a linear expansion coefficient after curing of 40 (× 10 ⁻⁶ / ° C.) or less;
In the recording head composed of
A recording head in which the clearance between the recording element substrates satisfies the following relationship.
“Maximum filler outer dimensions × 15 <Gap between recording element substrates <Sealing groove width × 2” The recording head according to claim 1, wherein the filler has a spherical shape. The recording head according to claim 1, wherein the filler has a rod shape.