Liquid discharge head and suction recovery method thereof

Abstract

To provide a liquid discharge head capable of suppressing an increase in the size of the head and suppressing clogging of a discharge port due to a foreign matter.SOLUTION: A liquid discharge head includes: a substrate 1 provided with at least one liquid supply path 40 for supplying liquid; a flow path forming member 2 provided with a plurality of discharge ports 10 for discharging the liquid, joined to the substrate 1, and forming a flow path 60 communicating with the plurality of discharge ports 10 and the at least one liquid supply path 40; and at least one discharge hole 70 for discharging the liquid and provided so as to penetrate the flow path forming member 2 in a region 3 facing the at least one liquid supply path 40 of the flow path forming member 2.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a liquid ejection head and a suction recovery method thereof. [Background technology]

[0002] In a liquid ejection head that ejects liquid, if foreign matter enters a flow path that communicates with an ejection port, the foreign matter may clog the ejection port, resulting in defective ejection of the liquid. Patent Document 1 describes an inkjet recording device that can suppress ejection defects caused by clogging of the ejection ports. This inkjet recording device has a group of ejection ports with small opening areas and a group of ejection ports with large opening areas. The group of ejection ports with large opening areas is arranged at the end of the arrangement direction of the group of ejection ports with small opening areas. The ejection ports with large opening areas are dummy ejection ports that do not contribute to recording. Foreign matter that has entered the flow path can be expelled by suctioning liquid from the ejection ports with large opening areas. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-231742 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the inkjet recording device described in Patent Document 1, the groups of ejection ports with large opening areas are arranged at both ends of the groups of ejection ports with small opening areas, which causes a problem in that the head becomes larger by the amount of space required to arrange the groups of ejection ports with large opening areas.

[0005] An object of the present invention is to provide a liquid ejection head that can prevent the head from becoming large and can prevent clogging of the ejection ports by foreign matter. [Means for solving the problem]

[0006] In order to achieve the above object, a liquid ejection head according to one aspect of the present invention is characterized by having a substrate having at least one liquid supply path for supplying liquid, a flow path forming member having a plurality of ejection ports for ejecting liquid, bonded to the substrate, and forming a flow path communicating with the plurality of ejection ports and the at least one liquid supply path, and at least one discharge hole for discharging liquid, the flow path forming member being provided in an area of ​​the flow path forming member facing the at least one liquid supply path so as to penetrate the flow path forming member. A liquid ejection head according to another aspect of the present invention is characterized by having a substrate having at least one liquid supply path for supplying liquid, a flow path forming member having a plurality of ejection ports for ejecting liquid, bonded to the substrate, and forming a flow path communicating with the plurality of ejection ports and the at least one liquid supply path, and at least one discharge hole for discharging liquid, the flow path forming member being provided so as to penetrate the flow path forming member in an area adjacent to the ejection port side of an area of ​​the flow path forming member facing the at least one liquid supply path. A liquid ejection head according to yet another aspect of the present invention comprises an ejection port array in which a plurality of ejection ports for ejecting liquid are arranged, at least one discharge hole for discharging liquid arranged to the side of the ejection port array, a flow path communicating with each ejection port of the ejection port array and the at least one discharge hole, and a plurality of energy generating elements that generate ejection energy for ejecting liquid, wherein the plurality of energy generating elements are opposed only to the plurality of ejection ports in the ejection direction of the liquid. [Effects of the Invention]

[0007] According to the present invention, it is possible to prevent the head from becoming large and to prevent clogging of the ejection ports due to foreign matter. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 2 is a perspective view showing an example of the configuration of a recording head. [Figure 2]FIG. 2 is an exploded perspective view of the recording head shown in FIG. [Figure 3] 1 is a schematic diagram illustrating the configuration of a liquid ejection head according to a first embodiment of the present invention. [Figure 4] 4 is a diagram for explaining the configuration of a liquid ejection portion of the recording element substrate shown in FIG. 3. FIG. [Figure 5] 10A and 10B are schematic diagrams illustrating the configuration of a cap for performing suction recovery. [Figure 6] FIG. 4 is a cross-sectional view showing a cross-sectional structure of a part of a recording element substrate with a cap attached. [Figure 7] FIG. 10 is a schematic diagram showing a state in which foreign matter is discharged from a discharge hole. [Figure 8] FIG. 4 is a cross-sectional view showing a cross-sectional structure of a part of a recording element substrate with a cap attached. [Figure 9] FIG. 2 is a diagram illustrating the configuration of a liquid ejection head of a first comparative example. [Figure 10] 10A and 10B are schematic diagrams showing how foreign matter moves in the liquid ejection portion shown in FIG. [Figure 11] FIG. 4 is a schematic diagram illustrating the configuration of a liquid ejection head according to a second embodiment of the present invention. [Figure 12] 12 is a diagram for explaining the configuration of a liquid ejection portion of the recording element substrate shown in FIG. 11. FIG. [Figure 13] 10A and 10B are schematic diagrams for explaining the configuration of a cap for performing suction recovery. [Figure 14] FIG. 4 is a cross-sectional view showing a cross-sectional structure of a part of a recording element substrate with a cap attached. [Figure 15] FIG. 10 is a schematic diagram showing a state in which foreign matter is discharged from a discharge hole. [Figure 16] FIG. 4 is a cross-sectional view showing a cross-sectional structure of a part of a recording element substrate with a cap attached. [Figure 17] FIG. 10 is a diagram illustrating the configuration of a liquid ejection head of a second comparative example. [Figure 18] 18A and 18B are schematic diagrams showing the movement of foreign matter in the liquid ejection portion shown in FIG. 17. [Figure 19]FIG. 10 is a schematic diagram illustrating the configuration of a liquid ejection head according to a third embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the embodiments are merely examples and are not intended to limit the scope of the present invention to the embodiments.

[0010] First, a recording head to which the liquid ejection head of the present invention can be applied will be described. 1 is a perspective view showing an example of the configuration of a print head 1000. Referring to FIG. 1, the print head 1000 has a print element unit 1100 and a tank holder unit 1200 to which the print element unit 1100 is attached.

[0011] Fig. 2 is an exploded perspective view of the print head 1000 shown in Fig. 1. The print element unit 1100 has a print element substrate 1101, an electrical wiring member 1102, and support members 1103 and 1104. The print element substrate 1101 is fixed onto the support member 1103 with an adhesive. The electrical wiring member 1102 and the support member 1104 are further fixed onto the support member 1103 with an adhesive. The electrical wiring member 1102 is electrically connected to the print element substrate 1101 using wire bonding, inner lead bonding, or the like.

[0012] The tank holder unit 1200 has a filter 1201, a tank chip 1202, an electrical contact substrate 1203, individual seal rubbers 1204, a flow path plate 1205, and a seal rubber 1206. The flow path plate 1205 is joined to the support member 1103 via the seal rubber 1206. A liquid such as ink is supplied to the tank holder unit 1200 from a liquid tank (not shown) that contains the liquid via the filter 1201. The supplied liquid is sent to the flow path plate 1205 via the tank chip 1202 and the individual seal rubbers 1204, and then supplied to the recording element substrate 1101 via the support member 1103.

[0013] In the above-described print head 1000, the liquid supplied through the filter 1201 comes into contact with various components before reaching the print element substrate 1101. During the manufacturing and assembly processes of the print head 1000, foreign matter is introduced into the components as the liquid comes into contact with them. Here, foreign matter is, for example, dust adhering to the components or the material of the components themselves. Furthermore, when replacing the liquid tank, foreign matter may also be introduced into the liquid supplied through the filter 1201. Note that although the components are washed and assembled in a clean room, it is difficult to completely remove foreign matter.

[0014] The liquid ejection head of the present invention is configured to suppress clogging of the ejection ports due to foreign matter. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the liquid ejection head of the present invention will be described in detail.

[0015] (First embodiment) Figure 3 is a schematic diagram illustrating the configuration of a liquid ejection head according to a first embodiment of the present invention. Figure 3(a) is a top view of a recording element substrate 1101. Figure 3(b) is a schematic diagram of a part of the liquid ejection portion of the recording element substrate 1101 shown in Figure 3(a) as viewed from the ejection port side. Fig. 4 is a diagram for explaining the configuration of the liquid ejection portion of the recording element substrate 1101 shown in Fig. 3(b). Fig. 4(a) is an enlarged view showing a part of the liquid ejection portion. Fig. 4(b) is a cross-sectional view taken along line AA of the liquid ejection portion shown in Fig. 4(a).

[0016] The liquid ejection head of this embodiment has a recording element substrate 1101 shown in Figures 3 and 4. The recording element substrate 1101 has a substrate 1 and a flow path forming member 2. The substrate 1 has a liquid supply path 40 for supplying liquid. The flow path forming member 2 has a plurality of ejection ports 10 for ejecting liquid, and is joined to the substrate 1 to form a flow path 60 that communicates with the plurality of ejection ports 10 and the liquid supply path 40. A plurality of discharge holes 70 for discharging liquid are provided in a region 3 of the flow path forming member 2 that faces the liquid supply path 40. Each discharge hole 70 is provided so as to penetrate the flow path forming member 2. Here, the shape of both the ejection ports 10 and the discharge holes 70 is circular.

[0017] The multiple ejection ports 10 are respectively connected to multiple pressure chambers 80. Each pressure chamber 80 is provided with a heater 30 as an energy generating element that generates ejection energy for ejecting liquid from the ejection port 10. Each pressure chamber 80 constitutes part of the flow path 60, and liquid from the liquid supply path 40 is supplied to each pressure chamber 80. The heater 30 faces only the ejection ports 10 in the ejection direction (Z direction) of the liquid. Note that the energy generating element is not limited to the heater 30. A piezoelectric element or the like may also be used as the energy generating element.

[0018] A plurality of filter members 20 made of columnar structures are disposed between the liquid supply channel 40 and each pressure chamber 80. Each pressure chamber 80 is partitioned by a channel wall 50, and has an opening (inlet) for supplying liquid to the liquid supply channel 40 side. The filter members 20 are disposed near the inlets of the pressure chambers 80. Of foreign matter such as dust that has entered the channel 60, foreign matter that is larger than the gap between the filter members 20 and the channel wall 50 is captured by the filter members 20.

[0019] The multiple ejection ports 10 include a first ejection port array 10A and a second ejection port array 10B. In both the first ejection port array 10A and the second ejection port array 10B, the ejection ports 10 are arranged in a line at a predetermined interval in the longitudinal direction (Y direction) of the recording element substrate 1100. The Y direction can be referred to as the first direction. The liquid supply path 40 extends in the Y direction. The multiple discharge holes 70 face the liquid supply path 40 in the Z direction, are located to the side of the first ejection port array 10A (second ejection port array 10B), and are arranged side by side at a predetermined interval in the Y direction. The Z direction indicates the direction perpendicular to the substrate surface (the ejection surface on which the ejection ports 10 are formed) of the recording element substrate 1100. In this embodiment, the diameter of the ejection port 10 is, for example, 15 μm, and the diameter of the discharge hole 70 is, for example, 18 μm. For example, twelve discharge holes 70 are arranged at equal intervals from one end to the other in the Y direction for one liquid supply channel 40. The number and positions of the discharge holes 70 for one liquid supply channel 40 are preferably set appropriately so that foreign matter can be efficiently discharged. For example, at least one discharge hole 70 may be arranged between the liquid supply channel 40 and the multiple ejection ports 10 of the flow channel 60. Furthermore, although the ejection ports 10 and the discharge holes 70 are circular in shape, they may also be elliptical or other shapes. In this case, the diameters of the ejection ports 10 and the discharge holes 70 may be the diameters of circles with equivalent areas.

[0020] In the liquid ejection head of this embodiment, foreign matter that has entered the flow path 60 from the liquid supply path 40 is discharged by sucking the liquid through the discharge hole 70. The foreign matter enters the flow path 60 from the liquid supply path 40. Therefore, the shorter the distance from the liquid supply path 40 to the discharge hole 70, the shorter the time required to discharge the foreign matter that has entered the flow path 60 from the discharge hole 70, and the less liquid is discharged when the foreign matter is discharged. In this embodiment, by providing the discharge hole 70 in the region 3 facing the liquid supply path 40, the foreign matter can be discharged in a short time, and the amount of liquid discharged when the foreign matter is discharged can be reduced.

[0021] The center of the discharge hole 70 is preferably located at the center of the width direction (X direction) of the liquid supply channel 40, which is perpendicular to the Y direction. This can shorten the time required to discharge foreign matter and reduce the amount of liquid discharged when the foreign matter is discharged. The X direction can be called the second direction. Furthermore, in the X direction, the midpoint between the first ejection port array 10A and the second ejection port array 10B is located directly above the liquid supply path 40. Therefore, by locating the array of discharge holes 70 at the midpoint between the first ejection port array 10A and the second ejection port array 10B, foreign matter can be discharged in a short time, and the amount of liquid discharged due to the discharge of foreign matter can be reduced.

[0022] The size of the discharge hole 70 is preferably set appropriately taking into consideration the size of foreign matter that may enter the flow path 60 from the liquid supply path 40 and cause clogging of the ejection port 10 . If the discharge hole 70 is made larger, it becomes difficult to form a meniscus (a curved surface of the liquid formed by interaction with the surface inside the hole), which may result in liquid leakage from the discharge hole 70. Even if a meniscus can be formed, if sufficient liquid retention force is not obtained, liquid may leak from the discharge hole 70 due to impact, etc. In addition, the larger the discharge hole 70, the greater the amount of liquid discharged due to the discharge of foreign matter. Taking these factors into consideration, it is preferable that the maximum diameter of the discharge hole 70 be twice the diameter of the ejection port 10. In other words, it is preferable that the diameter of the discharge hole 70 be no more than twice the diameter of the ejection port 10.

[0023] On the other hand, if the drain hole 70 is made smaller, sufficient liquid retention can be achieved in the meniscus, the amount of liquid discharged during foreign matter discharge can be reduced, and liquid leakage from the drain hole 70 can be suppressed; however, the size of foreign matter that can be discharged from the drain hole 70 becomes smaller. Taking these factors into consideration, in order to reduce the amount of liquid discharged due to foreign matter while suppressing clogging of the ejection port 10, it is preferable that the minimum diameter of the drain hole 70 be 1 / 3 of the diameter of the ejection port 10. Furthermore, taking into consideration the amount of liquid discharged and the size of foreign matter that may cause clogging of the ejection port 10, the filter member 20 is often designed to capture foreign matter of a size at least 1 / 3 of the diameter of the ejection port 10. In this case, it is sufficient that the drain hole 70 be able to discharge foreign matter of a size that cannot be captured by the filter member 20. From this perspective, it is also preferable that the minimum diameter of the drain hole 70 be 1 / 3 of the diameter of the ejection port 10. In other words, it is preferable that the diameter of the drain hole 70 be 1 / 3 or more of the diameter of the ejection port 10.

[0024] Next, a suction recovery method for the liquid ejection head of this embodiment will be described. This suction recovery method includes a first suction recovery operation in which liquid is sucked from the discharge holes 70 to discharge foreign matter, and a second suction recovery operation (normal suction recovery operation) in which liquid is sucked from the discharge ports 10 to fill the entire flow path 60 with liquid. 5A and 5B are schematic diagrams illustrating the configuration of the caps used in the first suction recovery operation, and FIG. 5B shows the caps used in the second suction recovery operation.

[0025] First, the first suction recovery operation will be described. The cap 200 shown in FIG. 5(a) is attached to the recording element substrate 1101 shown in FIG. 3(a). The cap 200 is provided with a suction hole 201 for each row of discharge holes 70. In this example, the recording element substrate 1101 has four rows of discharge holes 70, and therefore the cap 200 has four suction holes 201. Note that the number of suction holes 201 is not limited to four. The number of suction holes 201 can be changed as appropriate depending on the number of rows of discharge holes 70 and the number of rows of ejection ports 10.

[0026] Figure 6 is a cross-sectional view showing the cross-sectional structure of a portion of the recording element substrate 1101 with the cap 200 attached. In Figure 6, the cross-sectional portion of the recording element substrate 1101 is the same as the cross-sectional portion shown in Figure 4(b). The black arrows in Figure 6 indicate the flow of liquid. 6, the discharge hole 70 communicates with the suction hole 201 of the cap 200, and the discharge ports 10 on both sides of the discharge hole 70 are both blocked by the cap 200. In this state, when the pump 4A is used to suck liquid through the suction hole 201, the liquid passes through the liquid supply path 40, the flow path 60, the discharge hole 70, and the suction hole 201 in this order before being discharged.

[0027] FIG. 7 is a schematic diagram showing how foreign matter 5 is discharged from discharge hole 70 in the cross-sectional view shown in FIG. 6. The solid arrows in FIG. 7 indicate the flow of liquid. As shown in FIG. 7, foreign matter 5 passes through liquid supply path 40 and flow path 60 by the suction operation using pump 4A, and is then discharged from discharge hole 70. Note that foreign matter 5 larger in size than the diameter of discharge hole 70 will either block discharge hole 70 or remain in flow path 60. Large foreign matter 5 remaining in flow path 60 can be captured by filter member 20.

[0028] Next, the second suction recovery operation will be described. The cap 210 shown in FIG. 5(b) is attached to the recording element substrate 1101 shown in FIG. 3(a). The cap 210 is provided with suction holes (211A, 211B) for each of the rows (10A, 10B) of the ejection ports 10. The suction holes (211A, 211B) may be, for example, elongated slit-shaped. In this example, the recording element substrate 1101 is provided with four ejection port rows 10A and four ejection port rows 10B, and therefore the cap 200 has four suction holes 211A and four suction holes 211B. Each ejection port row 10A corresponds to one suction hole 211A, and each ejection port row 10B corresponds to one suction hole 211B. Note that the number of suction holes 211A and 211B is not limited to four. The number of suction holes 211A and 211B can be changed as appropriate depending on the number of rows of the ejection ports 10.

[0029] Figure 8 is a cross-sectional view showing the cross-sectional structure of a portion of the recording element substrate 1101 with the cap 210 attached. In Figure 8, the cross section of the recording element substrate 1101 is the same as the cross section shown in Figure 4(b). The black arrows in Figure 8 indicate the flow of liquid. As shown in Figure 8, the discharge hole 70 is blocked by the cap 210, and the discharge ports 10 (10A) and 10 (10B) on either side of the discharge hole 70 are connected to the suction holes 211A and 211B of the cap 210, respectively. In this state, when the pump 4B is used to suck liquid through the suction holes 211A and 211B, the liquid is discharged after passing through the liquid supply path 40, the flow path 60, the discharge hole 10, and the suction holes 211A and 211B. This allows the entire flow path 60 to be filled with liquid. Note that a single pump may be used as both the pump 4A and the pump 4B.

[0030] Next, how ejection defects occur due to clogging of the ejection ports will be described using the liquid ejection head of the first comparative example, which does not have the ejection holes 70, as an example.

[0031] Figure 9 is a diagram illustrating the configuration of a liquid ejection head of a first comparative example. Figure 9(a) is an enlarged view showing a portion of the liquid ejection portion. Figure 9(b) is a cross-sectional view taken along line AA of the liquid ejection portion shown in Figure 9(a). The solid arrows in Figure 9(b) indicate the flow of liquid. The liquid ejection head of the first comparative example shown in Fig. 9 has the same configuration as the liquid ejection portion shown in Fig. 4, except that it does not have the discharge hole 70. The size of the gap between the filter member 20 and the flow path wall 50 is 3 µm.

[0032] In the liquid ejection head of the first comparative example, during the manufacturing process, assembly process, and when replacing the liquid tank, a suction recovery operation is performed to suck liquid from the ejection port 10, filling the entire flow path 60 with liquid. As shown in FIG. 9(b), the suction recovery operation causes the liquid to pass through the liquid supply path 40 and the flow path 60 and be discharged from the ejection port 10. This allows the entire flow path 60 to be filled with liquid.

[0033] FIG. 10 is a schematic diagram showing the movement of foreign matter 5 in FIG. 9. FIG. 10(a) corresponds to FIG. 9(a), and FIG. 10(b) corresponds to FIG. 9(b). As shown in FIG. 10, when the suction recovery operation is performed, foreign matter 5 enters flow path 60 from liquid supply path 40, and after passing through filter member 20, foreign matter 5 heads toward ejection port 10. In region 6A outside pressure chamber 80, when foreign matter 5 is captured by filter member 20, ejection defects do not occur. However, in region 6B inside pressure chamber 80, foreign matter 5 clogs ejection port 10, resulting in ejection defects.

[0034] In the liquid ejection head of this embodiment, during the manufacturing process, assembly process, and when replacing the liquid tank, a first suction recovery operation is performed to remove foreign matter, and then a second suction recovery operation is performed to fill the entire flow path 60 with liquid. This makes it possible to suppress ejection defects caused by clogging of the ejection ports 10, thereby improving yield and print quality.

[0035] Furthermore, the liquid ejection head of this embodiment has the following advantages over the inkjet recording apparatus described in Patent Document 1.

[0036] With the recent trend toward smaller liquid ejection heads, it has become necessary to also miniaturize the recording element substrate. In the inkjet recording device described in Patent Document 1, the ejection orifice groups with larger opening areas are arranged at both ends of the ejection orifice groups with smaller opening areas, so the recording element substrate becomes larger by the amount of space required to arrange the ejection orifice groups with larger opening areas. In contrast to this, in the liquid ejection head of this embodiment, the discharge holes 70 are provided in the region 3 facing the liquid supply path 40, so that the increase in size of the recording element substrate 1101 due to the formation of the discharge holes 70 can be suppressed.

[0037] (Second embodiment) Figure 11 is a schematic diagram illustrating the configuration of a liquid ejection head according to a second embodiment of the present invention. Figure 11(a) is a top view of a recording element substrate 1101. Figure 11(b) is a schematic diagram of a part of the liquid ejection portion of the recording element substrate 1101 shown in Figure 11(a) as seen from the ejection port side. Fig. 12 is a diagram for explaining the configuration of the liquid ejection portion of the recording element substrate 1101 shown in Fig. 11(b). Fig. 11(a) is an enlarged view showing a part of the liquid ejection portion. Fig. 11(b) is a cross-sectional view taken along line AA of the liquid ejection portion shown in Fig. 11(a).

[0038] The liquid ejection head of this embodiment is a circulation type head and has a recording element substrate 1101 shown in FIGS. 11 and 12. The liquid ejection head of this embodiment is basically composed of the same components as those of the first embodiment, except that it is configured to circulate liquid. The substrate 1 is provided with a plurality of liquid supply channels 40a and a plurality of liquid recovery channels 40b for circulating the liquid. A plurality of ejection ports 10 are arranged side by side in the Y direction at predetermined intervals. On one side of the row of ejection ports 10 in the X direction, a plurality of liquid supply channels 40a are arranged side by side at predetermined intervals in the Y direction, and on the other side in the X direction, a plurality of liquid recovery channels 40b are arranged side by side at predetermined intervals in the Y direction. Each ejection port 10, each liquid supply channel 40a, and each liquid recovery channel 40b are connected to a flow path 60.

[0039] A pressure chamber 80 is provided for each ejection port 10. Each pressure chamber 80 is partitioned by a flow path wall 50 and has an opening serving as an inlet on the liquid supply path 40a side and an opening serving as an outlet on the liquid recovery path 40b side. A filter member 20 is disposed near the inlet and near the outlet of each pressure chamber 80. During liquid ejection operation of the liquid ejection head, liquid is supplied from the liquid supply path 40a to the pressure chamber 80, and the liquid that is not ejected thereafter flows from the pressure chamber 80 to the liquid recovery path 40b. On the other hand, during a suction recovery operation in which liquid is sucked from the ejection port 10, liquid is supplied to the pressure chamber 80 from both the liquid supply path 40a and the liquid recovery path 40b and is then discharged from the ejection port 10. At this time, of the foreign matter that has entered the flow path 60, any foreign matter larger than the gap between the filter member 20 and the flow path wall 50 is captured by the filter member 20.

[0040] Drain holes 70 are provided in each of the region 3a facing the liquid supply channel 40a of the flow path forming member 2 and the region 3b facing the liquid recovery channel 40b of the flow path forming member 2. In the present embodiment, one drain hole 70 is provided for each liquid supply channel 40a, and another drain hole 71 is provided for each liquid recovery channel 40b, but this is not limited to this. Two or more drain holes 70 may be provided for each liquid supply channel 40a. Similarly, two or more drain holes 71 may be provided for each liquid recovery channel 40b. Note that the number and positions of the drain holes 70, 71 are preferably set appropriately so that foreign matter can be efficiently discharged.

[0041] In the liquid ejection head of this embodiment, foreign matter that has entered the flow path 60 is discharged from the liquid supply path 40a and the liquid recovery path 40b by suctioning liquid through the discharge holes 70 and 71. Foreign matter enters the flow path 60 from both the liquid supply path 40a and the liquid recovery path 40b. Therefore, the shorter the distance from the liquid supply path 40a to the discharge hole 70, the shorter the time required to discharge foreign matter from the discharge hole 70, and the less liquid is discharged when the foreign matter is discharged. Similarly, the shorter the distance from the liquid recovery path 40b to the discharge hole 71, the shorter the time required to discharge foreign matter from the discharge hole 71, and the less liquid is discharged when the foreign matter is discharged. In this embodiment, by providing the discharge hole 70 in the region 3a facing the liquid supply path 40a and the discharge hole 71 in the region 3b facing the liquid recovery path 40b, foreign matter can be discharged in a short time and the less liquid is discharged when the foreign matter is discharged.

[0042] The center of drain hole 70 facing liquid supply channel 40a is preferably located on the center of liquid supply channel 40a when viewed from the Z direction. Similarly, the center of drain hole 71 facing liquid recovery channel 40b is preferably located on the center of liquid recovery channel 40b when viewed from the Z direction. This makes it possible to shorten the time required to discharge foreign matter and reduce the amount of liquid discharged when the foreign matter is discharged.

[0043] In the liquid ejection head of this embodiment, for the reasons explained in the first embodiment, it is preferable that the maximum diameter of the discharge holes 70, 71 is twice the diameter of the ejection port 10, and the minimum diameter of the discharge hole 70 is one-third the diameter of the ejection port 10. As in the first embodiment, in this embodiment as well, the diameter of the ejection port 10 is set to, for example, 15 μm, and the diameter of the discharge holes 70, 71 is set to, for example, 18 μm.

[0044] Next, a suction recovery method for the liquid ejection head of this embodiment will be described. As in the first embodiment, this suction recovery method also includes a first suction recovery operation in which liquid is sucked from the discharge holes 70 and 71 to discharge foreign matter, and a second suction recovery operation (normal suction recovery operation) in which liquid is sucked from the ejection ports 10 to fill the entire flow path 60 with liquid. Fig. 13 is a schematic diagram illustrating the configuration of a cap for performing suction recovery. Fig. 13(a) shows the cap used in the first suction recovery operation, and Fig. 13(b) shows the cap used in the second suction recovery operation.

[0045] First, the first suction recovery operation will be described. The cap 220 shown in FIG. 13(a) is attached to the recording element substrate 1101 shown in FIG. 11(a). The cap 220 is provided with suction holes 221 (221A, 221B) for each row of discharge holes 70, 71. Here, two rows of discharge holes, one row of discharge holes 70 and one row of discharge holes 71, are provided for one row of ejection ports 10 on the recording element substrate 1101. A suction hole 221A is provided for one row of discharge holes 70, and a suction hole 221B is provided for the other row of discharge holes 71. These suction holes 221A, 221B may be, for example, elongated slit-shaped. Since the recording element substrate 1101 has four rows of ejection ports 10, the cap 200 has four suction holes 211A and four suction holes 211B.

[0046] Figure 14 is a cross-sectional view showing the cross-sectional structure of a portion of the recording element substrate 1101 with the cap 220 attached. In Figure 14, the cross-sectional portion of the recording element substrate 1101 is the same as the cross-section shown in Figure 12(b). The black arrows in Figure 14 indicate the flow of liquid. 14, discharge hole 70 facing liquid supply channel 40a communicates with suction hole 211A of cap 220, and discharge hole 71 facing liquid recovery channel 40b communicates with suction hole 211B of cap 220. Discharge port 10 located between suction hole 211A and suction hole 211B is blocked by cap 220. In this state, when pump 4A is used to suck liquid through suction holes 211A and 211B, the liquid flows from both liquid supply channel 40a and liquid recovery channel 40b into flow path 60, and then passes through discharge holes 70 and 71 to be discharged from suction holes 211A and 211B.

[0047] FIG. 15 is a schematic diagram showing how foreign matter 5 is discharged from discharge holes 70, 71 in the cross-sectional view shown in FIG. 14. The solid arrows in FIG. 15 indicate the flow of liquid. As shown in FIG. 15, foreign matter 5 enters flow path 60 from both liquid supply path 40a and liquid recovery path 40b due to the suction operation using pump 4A, and is then discharged from discharge holes 70, 71. Note that foreign matter 5 larger in size than the diameter of discharge holes 70, 71 will block discharge holes 70, 71 or remain in flow path 60. Large foreign matter 5 remaining in flow path 60 can be captured by filter member 20.

[0048] Next, the second suction recovery operation will be described. The cap 230 shown in FIG. 13(b) is attached to the recording element substrate 1101 shown in FIG. 11(a). The cap 230 has a suction hole 231 for each row of the ejection ports 10. The suction holes 231 may be, for example, in the shape of a long, thin slit. In this example, the recording element substrate 1101 has four rows of the ejection ports 10, and therefore the cap 230 has four suction holes 231. Note that the number of suction holes 231 is not limited to four. The number of suction holes 231 can be changed as appropriate depending on the number of rows of the ejection ports 10.

[0049] Figure 16 is a cross-sectional view showing the cross-sectional structure of a portion of the recording element substrate 1101 with the cap 230 attached. In Figure 16, the cross-sectional portion of the recording element substrate 1101 is the same as the cross-section shown in Figure 12(b). The black arrows in Figure 16 indicate the flow of liquid. 16, discharge holes 70 and 71 are blocked by cap 230, and discharge port 10 is in communication with suction hole 231 of cap 230. When pump 4B is used to suck liquid through suction hole 231 in this state, the liquid flows into flow path 60 from both liquid supply path 40a and liquid recovery path 40b, and then passes through discharge hole 10 and suction hole 231 before being discharged. This allows the entire flow path 60 to be filled with liquid. Note that pump 4A and pump 4B may share a single pump.

[0050] Next, a description will be given of how ejection defects occur due to clogging of the ejection ports in a liquid ejection head of a second comparative example that does not have the ejection holes 70 and 71.

[0051] Figure 17 is a diagram illustrating the configuration of a liquid ejection head of a second comparative example. Figure 17(a) is an enlarged view showing a portion of the liquid ejection portion. Figure 17(b) is a cross-sectional view of the liquid ejection portion shown in Figure 17(a) taken along line AA. The liquid ejection head of the second comparative example shown in Figure 17 has the same configuration as the liquid ejection portion shown in Figure 12, except that it does not have discharge holes 70, 71. The black arrows in Figure 17(b) indicate the flow of liquid.

[0052] In the liquid ejection head of the second comparative example, during the manufacturing process, assembly process, and when replacing the liquid tank, a suction recovery operation is performed to suck liquid from the ejection ports 10, filling the entire flow path 60 with liquid. As shown in FIG. 17(b), the suction recovery operation causes liquid to flow into the flow path 60 from both the liquid supply path 40a and the liquid recovery path 40b, and then the liquid is discharged from the ejection ports 10. This allows the entire flow path 60 to be filled with liquid.

[0053] FIG. 18 is a schematic diagram showing the movement of foreign matter 5 in FIG. 17. FIG. 18(a) corresponds to FIG. 17(a), and FIG. 18(b) corresponds to FIG. 17(b). As shown in FIG. 18, when the suction recovery operation is performed, foreign matter 5 enters flow path 60 from both liquid supply path 40a and liquid recovery path 40b, and foreign matter 5 that passes through filter member 20 heads toward ejection port 10. In region 6A outside pressure chamber 80, when foreign matter 5 is captured by filter member 20, ejection defects do not occur. However, in region 6B inside pressure chamber 80, foreign matter 5 clogs ejection port 10, resulting in ejection defects.

[0054] In the liquid ejection head of this embodiment, during the manufacturing process, assembly process, and when replacing the liquid tank, a first suction recovery operation is performed to remove foreign matter, and then a second suction recovery operation is performed to fill the entire flow path 60 with liquid. This makes it possible to suppress ejection defects caused by clogging of the ejection ports 10, thereby improving yield and print quality. Furthermore, for the same reason as in the first embodiment, in the liquid ejection head of this embodiment, it is possible to prevent the recording element substrate 1101 from becoming larger in size due to the formation of the discharge holes 70 and 71. In the liquid ejection head of this embodiment, only one of the drain holes 70 and the drain holes 71 may be provided for the liquid supply channel 40a and the liquid recovery channel 40b. The diameter of the drain holes 70 provided for the liquid supply channel 40a may be different from the diameter of the drain holes 71 provided for the liquid recovery channel 40b. For example, the diameter of the drain holes 70 provided for the liquid supply channel 40a may be larger than the diameter of the ejection port 10, and the diameter of the drain holes 71 provided for the liquid recovery channel 40b may be larger than the diameter of the ejection port 10. In this case, for example, a first suction recovery operation is performed during the manufacturing process to actively clog the drain holes 71 on the liquid recovery channel 40b side with foreign matter. When replacing the liquid tank, the first suction recovery operation is performed to discharge foreign matter from the drain holes 70 on the liquid supply channel 40a side. This reduces the amount of liquid discharged due to the discharge of foreign matter.

[0055] (Third embodiment) Figure 19 is a schematic diagram illustrating the configuration of a liquid ejection head according to a third embodiment of the present invention. Figure 19(a) is a cross-sectional view of a portion of a recording element substrate 1101. Figure 19(b) is a cross-sectional view of a portion of the recording element substrate 1101 with a cap 240 attached. In Figure 19(b), the cross-sectional portion of the recording element substrate 1101 is the same as the cross-sectional portion shown in Figure 19(a). The solid arrows in Figure 19 indicate the flow of liquid.

[0056] The liquid ejection head of this embodiment has the same configuration as that of the second embodiment, except that the discharge holes 70, 71 are arranged in positions close to the ejection ports 10. The same components are denoted by the same reference numerals, and detailed description thereof will be omitted here.

[0057] 19(a), a drain hole 70 is provided in region 3c adjacent to the ejection port side of region 3a facing liquid supply channel 40a. In flow path 60, drain hole 70 is disposed between liquid supply channel 40a and the plurality of ejection ports 10, more specifically, between liquid supply channel 40a and filter member 20. In addition, another drain hole 71 is provided in region 3d adjacent to the ejection port side of region 3b facing liquid recovery channel 40b. In flow path 60, another drain hole 71 is disposed between liquid recovery channel 40b and the plurality of ejection ports 10, more specifically, between liquid recovery channel 40b and filter member 20.

[0058] In the liquid ejection head of this embodiment, suction recovery is performed using a cap 240 shown in FIG. 19(b). The cap 240 has a suction hole 241. When the cap 240 is attached to the liquid ejection head, the suction hole 241 is connected to the ejection port 10 and the discharge holes 70 and 71 on either side of it. When the pump 4 is used to suck liquid through the suction hole 231 in this state, the liquid flows into the flow path 60 from both the liquid supply path 40a and the liquid recovery path 40b. The liquid that flows into the flow path 60 passes through the discharge holes 70 and 71 and is discharged from the suction hole 241, and also passes through the filter member 20 and the ejection port 10 and is discharged from the suction hole 241. Foreign matter 5 enters the flow path 60 from both the liquid supply path 40a and the liquid recovery path 40b and is then discharged from the discharge holes 70 and 71. Note that foreign matter 5 larger in diameter than the discharge holes 70 and 71 either blocks the discharge hole 70 or remains in the flow path 60. Large foreign matter 5 remaining in the flow path 60 can be captured by the filter member 20.

[0059] According to the liquid ejection head of this embodiment, in addition to the effects described in the first and second embodiments, it is possible to simultaneously fill the flow path 60 with liquid and discharge the foreign matter 5 in one suction recovery operation. Furthermore, in the flow path 60, the discharge hole 70 is disposed between the liquid supply path 40a and the plurality of ejection ports 10, and the discharge hole 71 is disposed between the liquid recovery path 40b and the plurality of ejection ports 10. With this configuration, there is no need to secure additional space for disposing the discharge holes 70, 71. Therefore, as with the first and second embodiments, in the liquid ejection head of this embodiment, it is possible to prevent the recording element substrate 1101 from becoming larger due to the formation of the discharge holes 70, 71.

[0060] In the liquid ejection heads of the first and second embodiments, it is also possible to simultaneously fill the flow path 60 with liquid and discharge foreign matter 5 in a single suction recovery operation. In the liquid ejection head of the first embodiment, for example, the suction hole 201 of the cap 200 shown in FIG. 6 is configured to communicate with the discharge hole 70 and the discharge ports 10 on both sides of it. This makes it possible to simultaneously fill the flow path 60 with liquid and discharge foreign matter 5. Also, in the liquid ejection head of the second embodiment, for example, the suction hole 231 of the cap 230 shown in FIG. 16 is configured to communicate with the discharge port 10 and the discharge holes 70 and 71 on both sides of it. This makes it possible to simultaneously fill the flow path 60 with liquid and discharge foreign matter 5.

[0061] The disclosure of this embodiment includes the following configurations and methods. (Configuration 1) a substrate having at least one liquid supply channel for supplying a liquid; a flow path forming member that is provided with a plurality of discharge ports for discharging a liquid, is bonded to the substrate, and forms a flow path that communicates with the plurality of discharge ports and the at least one liquid supply path; a liquid ejection head having at least one discharge hole for discharging liquid, the discharge hole being provided in a region of the flow path forming member facing the at least one liquid supply path so as to penetrate the flow path forming member. (Configuration 2) a substrate having at least one liquid supply channel for supplying a liquid; a flow path forming member that is provided with a plurality of discharge ports for discharging a liquid, is bonded to the substrate, and forms a flow path that communicates with the plurality of discharge ports and the at least one liquid supply path; and at least one discharge hole for discharging liquid, the discharge hole being provided so as to penetrate the flow path forming member in a region adjacent to the discharge port side of a region of the flow path forming member facing the at least one liquid supply path. (Configuration 3) 3. The liquid ejection head according to claim 1, wherein the diameter of the at least one discharge hole is equal to or less than twice the diameter of the ejection port. (Configuration 4) 3. The liquid ejection head according to claim 1, wherein the diameter of the at least one discharge hole is at least 1 / 3 the diameter of the ejection port. (Configuration 5) The liquid ejection head according to at least one of configurations 1, 3, and 4, wherein the at least one discharge hole faces the at least one liquid supply path. (Configuration 6) A liquid ejection head as described in configuration 5, characterized in that the multiple ejection ports are arranged in a first direction, the at least one liquid supply path extends in the first direction, and the center of the at least one discharge hole is located on the center of the width of the at least one liquid supply path. (Configuration 7) A liquid ejection head described in at least one of configurations 1, 3 to 5, characterized in that the plurality of ejection ports have a first ejection port row and a second ejection port row, each of which has the ejection ports arranged side by side in a first direction, and the at least one discharge hole has a discharge hole row, in which the plurality of ejection holes are arranged side by side in the first direction, and the discharge hole row is arranged at an intermediate position between the first ejection port row and the second ejection port row in a second direction perpendicular to the first direction. (Configuration 8) the substrate is provided with at least one liquid recovery path that communicates with the flow path and recovers liquid; A liquid ejection head according to at least one of configurations 1 to 7, characterized in that it has at least one other discharge hole for discharging liquid, which is provided so as to penetrate the flow path forming member in a region of the flow path forming member facing the at least one liquid recovery path or in a region adjacent to the discharge port side of that region. (Configuration 9) 9. The liquid ejection head according to configuration 8, wherein the diameter of the at least one other discharge hole is equal to or less than twice the diameter of the ejection port. (Configuration 10) 9. The liquid ejection head according to configuration 8, wherein the diameter of the at least one other discharge hole is at least 1 / 3 the diameter of the ejection port. (Configuration 11) 11. The liquid ejection head according to any one of configurations 8 to 10, wherein the at least one other discharge hole faces the at least one liquid recovery path. (Configuration 12) A liquid ejection head as described in configuration 11, characterized in that the multiple ejection ports are arranged in a first direction, the at least one liquid recovery path extends in the first direction, and the center of the at least one other discharge hole is located on the center of the width of the at least one liquid recovery path. (Configuration 13) 13. The liquid ejection head of any one of configurations 8 to 12, wherein the diameter of the at least one ejection hole is different from the diameter of the at least one other ejection hole. (Configuration 14) an ejection port array in which a plurality of ejection ports for ejecting liquid are arranged; at least one discharge hole for discharging liquid, the discharge hole being arranged to the side of the discharge port row; a flow path communicating with each outlet of the outlet array and the at least one discharge hole; a plurality of energy generating elements that generate ejection energy for ejecting liquid; A liquid ejection head, wherein the plurality of energy generating elements are opposed to only the plurality of ejection ports in the ejection direction of the liquid. (Method 1) A suction recovery method for a liquid ejection head according to any one of configurations 1 to 7 and 14, comprising: a step of aspirating liquid from the at least one discharge hole while the plurality of discharge ports are blocked, and discharging the liquid from the at least one discharge hole; and filling the flow path with liquid by sucking liquid from the plurality of discharge ports while the at least one discharge hole is blocked. (Method 2) A suction recovery method for a liquid ejection head according to any one of configurations 1 to 7 and 14, comprising: A suction recovery method comprising the steps of: sucking liquid from the plurality of discharge ports and the at least one discharge hole to fill the flow path with liquid; and discharging the liquid from the at least one discharge hole. (Method 3) A suction recovery method for a liquid ejection head according to any one of configurations 8 to 13, comprising: a step of aspirating liquid from the at least one discharge hole and the at least one other discharge hole while the plurality of discharge ports are blocked, and discharging the liquid from the at least one discharge hole and the at least one other discharge hole; a step of filling the flow path with liquid by sucking liquid from the plurality of discharge ports while blocking the at least one discharge hole and the at least one other discharge hole. (Method 4) A suction recovery method for a liquid ejection head according to any one of configurations 8 to 13, comprising: A suction recovery method comprising the steps of: sucking liquid from the plurality of discharge ports, the at least one discharge hole, and the at least one other discharge hole to fill the flow path with liquid; and discharging the liquid from the at least one discharge hole and the at least one other discharge hole. [Explanation of symbols]

[0062] 1 board 2 Flow path forming member 3 areas 10 outlet 40 Liquid supply path 60 flow paths 70 Discharge hole

Claims

1. a substrate having at least one liquid supply path for supplying a liquid; a flow path forming member that is provided with a plurality of discharge ports for discharging a liquid, that is bonded to the substrate, and that forms a flow path that communicates with the plurality of discharge ports and the at least one liquid supply path; a liquid ejection head having at least one discharge hole for discharging liquid, the discharge hole being provided in a region of the flow path forming member facing the at least one liquid supply path so as to penetrate the flow path forming member.

2. a substrate having at least one liquid supply path for supplying a liquid; a flow path forming member that is provided with a plurality of discharge ports for discharging a liquid, that is bonded to the substrate, and that forms a flow path that communicates with the plurality of discharge ports and the at least one liquid supply path; a liquid ejection head characterized by having at least one discharge hole for discharging liquid, the discharge hole being provided so as to penetrate the flow path forming member in an area adjacent to the ejection port side of an area of ​​the flow path forming member facing the at least one liquid supply path.

3. 3. The liquid ejection head according to claim 1, wherein the diameter of the at least one discharge hole is equal to or smaller than twice the diameter of the ejection port.

4. 3. The liquid ejection head according to claim 1, wherein the diameter of the at least one discharge hole is at least one-third the diameter of the ejection port.

5. 2. The liquid ejection head according to claim 1, wherein the at least one discharge hole faces the at least one liquid supply path.

6. 6. A liquid ejection head as described in claim 5, characterized in that the plurality of ejection ports are arranged in a first direction, the at least one liquid supply path extends in the first direction, and the center of the at least one discharge hole is located on the center of the width direction of the at least one liquid supply path.

7. 2. The liquid ejection head according to claim 1, wherein the plurality of ejection ports have a first ejection port row and a second ejection port row, each of which has the ejection ports arranged in a first direction, and the at least one discharge hole has a discharge hole row, in which a plurality of discharge holes are arranged in the first direction, and the discharge hole row is arranged at an intermediate position between the first ejection port row and the second ejection port row in a second direction perpendicular to the first direction.

8. the substrate is provided with at least one liquid recovery path that communicates with the flow path and recovers liquid; 3. A liquid ejection head as described in claim 1 or claim 2, characterized in that it has at least one other discharge hole for discharging liquid, which is provided so as to penetrate the flow path forming member in a region of the flow path forming member facing the at least one liquid recovery path or in a region adjacent to the discharge port side of that region.

9. 9. The liquid ejection head according to claim 8, wherein the diameter of the at least one other discharge hole is equal to or less than twice the diameter of the ejection port.

10. 9. The liquid ejection head according to claim 8, wherein the diameter of the at least one other discharge hole is at least 1 / 3 the diameter of the ejection port.

11. 9. The liquid ejection head according to claim 8, wherein the at least one other discharge hole faces the at least one liquid recovery path.

12. A liquid ejection head as described in claim 11, characterized in that the multiple ejection ports are arranged in a first direction, the at least one liquid recovery path extends in the first direction, and the center of the at least one other discharge hole is located on the center of the width of the at least one liquid recovery path.

13. 9. The liquid ejection head according to claim 8, wherein the diameter of the at least one ejection hole is different from the diameter of the at least one other ejection hole.

14. an ejection port array in which a plurality of ejection ports for ejecting liquid are arranged; at least one discharge hole for discharging liquid, the discharge hole being arranged to the side of the discharge port row; a flow path communicating with each outlet of the outlet array and the at least one discharge hole; a plurality of energy generating elements that generate ejection energy for ejecting liquid; A liquid ejection head, wherein the plurality of energy generating elements are opposed to only the plurality of ejection ports in the ejection direction of the liquid.

15. 15. A suction recovery method for a liquid ejection head according to claim 1, 2, or 14, comprising: a step of aspirating liquid from the at least one discharge hole while the plurality of discharge ports are blocked, and discharging the liquid from the at least one discharge hole; and filling the flow path with liquid by sucking liquid from the plurality of discharge ports while the at least one discharge hole is blocked.

16. 15. A suction recovery method for a liquid ejection head according to claim 1, 2, or 14, comprising: A suction recovery method comprising the steps of: sucking liquid from the plurality of discharge ports and the at least one discharge hole to fill the flow path with liquid; and discharging the liquid from the at least one discharge hole.

17. 9. The suction recovery method for a liquid ejection head according to claim 8, a step of aspirating liquid from the at least one discharge hole and the at least one other discharge hole while the plurality of discharge ports are blocked, and discharging the liquid from the at least one discharge hole and the at least one other discharge hole; and filling the flow path with liquid by sucking liquid from the plurality of discharge ports while blocking the at least one discharge hole and the at least one other discharge hole.

18. 9. The suction recovery method for a liquid ejection head according to claim 8, A suction recovery method comprising the steps of: sucking liquid from the plurality of discharge ports, the at least one discharge hole, and the at least one other discharge hole to fill the flow path with liquid; and discharging the liquid from the at least one discharge hole and the at least one other discharge hole.

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