Liquid discharge head

Abstract

To provide a liquid discharge head which comprises individual flow channels communicating with a discharge port and in which liquid circulates in the individual flow channels, and in which liquid having flown out from the individual flow channels is prevented from re-entering the individual flow channels.SOLUTION: A liquid discharge head 100 comprises: a substrate 1 having a first surface 1A, and a second surface 1B being a rear face of the first surface 1A; a plurality of individual flow channels 4 which are provided on the first surface 1A of the substrate 1, communicate with a discharge port 5 of liquid, and in which liquid re-circulates; and circulation flow channels 8-12 which communicate with the plurality of individual flow channels 4 and in which liquid re-circulates. The circulation flow channels 8-12 include: a connection region 8 which is provided on the first surface 1A of the substrate 1 and communicates with an outflow port 42 of the plurality of individual flow channels 4; a supply open hole 9 which penetrates the substrate 1 and supplies liquid to the connection region 8; and a recovery open hole 10 which penetrates the substrate 1 and recovers liquid from the connection region 8.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a liquid ejection head.

Background Art

[0002] In a liquid ejection head that ejects a liquid such as ink, the volatile components in the liquid may evaporate, causing the liquid near the ejection port to thicken. The thickening of the liquid may affect the ejection speed and landing accuracy of the ejected droplets. In order to suppress the thickening of the liquid, it has been proposed to cause a minute liquid circulation (micro circulation) in an individual flow path including the ejection port and a larger-scale liquid circulation (macro circulation) in a common flow path communicating with the individual flow path. Patent Document 1 discloses a liquid ejection head in which a micro circulation region is provided on one surface of a substrate and a macro circulation region is provided on the other surface, and these regions are communicated with each other by through holes provided in the substrate. Patent Document 2 discloses a liquid ejection head in which an individual flow path performing micro circulation is arranged close to a common flow path performing macro circulation.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the liquid ejection head described in Patent Document 1, the microcirculation region and the macrocirculation region are separated. As a result, concentrated ink that flows out from the individual channels is easily re-introduced from the individual channels by microcirculation. In the liquid ejection head described in Patent Document 2, concentrated ink that flows out from the individual channels is accumulated downstream by macrocirculation. However, when ink is ejected from the ejection port, ink is supplied from the inlet and outlet of the individual channels, so concentrated ink is also supplied to the individual channels from the outlet. Therefore, these liquid ejection heads may not be able to suppress the thickening of the ink near the ejection port.

[0005] The present invention aims to provide a liquid discharge head having individual flow channels that communicate with a discharge port, which allows liquid to circulate through the individual flow channels and suppresses the re-inflow of liquid that has flowed out of the individual flow channels into the individual flow channels. [Means for solving the problem]

[0006] The liquid discharge head of the present invention comprises a substrate having a first surface and a second surface which is the back surface of the first surface; a plurality of individual channels provided on the first surface of the substrate, communicating with a liquid discharge port and through which the liquid is recirculated; and a circulation channel communicating with the plurality of individual channels and through which the liquid is recirculated. The circulation channel is provided on the first surface of the substrate and has a connection region communicating with the outlets of the plurality of individual channels; a supply through-hole that penetrates the substrate and supplies liquid to the connection region; and a recovery through-hole that penetrates the substrate and recovers liquid from the connection region. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a liquid discharge head having individual flow paths that communicate with a discharge port, which allows liquid to circulate through the individual flow paths and suppresses the re-inflow of liquid that has flowed out of the individual flow paths into the individual flow paths. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic diagram of the main parts of the liquid discharge head according to the first embodiment of the present invention. [Figure 2]This is a schematic diagram of the main part of a liquid discharge head according to a second embodiment of the present invention. [Figure 3] This is a schematic diagram of the main parts of a liquid discharge head according to a third embodiment of the present invention. [Figure 4] This is a schematic diagram of the main parts of a liquid discharge head according to a fourth embodiment of the present invention. [Figure 5] This is a schematic diagram of the main parts of a liquid discharge head according to a fifth embodiment of the present invention. [Figure 6] This is a schematic diagram of the main parts of a liquid discharge head according to the sixth embodiment of the present invention. [Figure 7] This is a schematic diagram of the main parts of a comparative example liquid dispensing head. [Modes for carrying out the invention]

[0009] The following describes some embodiments of the liquid ejection head of the present invention with reference to the drawings. The embodiments described below are suitable specific examples of the present invention and are therefore subject to various technically preferred limitations. However, it goes without saying that the present invention is not limited to these embodiments. The liquid ejection head of the present invention is applicable to devices such as printers, copiers, facsimile machines with communication systems, word processors with printer units, and industrial recording devices combined with various processing devices. The following embodiments focus on ink ejection heads that eject ink, but the present invention can also be used for applications that eject liquids other than ink, such as biochip manufacturing and electronic circuit printing.

[0010] In the following description and drawings, the first surface 1A of the substrate 1 is the surface on which the individual flow channels 4 and discharge ports 5 are formed, and the second surface 1B of the substrate 1 is the back surface of the first surface 1A. The first direction X is parallel to the first and second surfaces 1A and 1B of the substrate 1 and is the direction in which the flow channel row 31, discharge port row 32, and through-hole row 33-35 described below extend. The first direction X corresponds to the longitudinal direction of the liquid discharge head 100. The second direction Y is parallel to the first and second surfaces 1A and 1B of the substrate 1 and is perpendicular to the first direction X. The second direction Y corresponds to the short direction of the liquid discharge head 100. The Z direction is perpendicular to the first and second surfaces 1A and 1B of the substrate 1, that is, perpendicular to the first direction X and the second direction Y.

[0011] (First embodiment) Figure 1 is a schematic diagram illustrating in detail the vicinity of the discharge port 5 of the liquid discharge head 100 of the first embodiment. Figure 1(a) is a plan view of the liquid discharge head 100 as seen from the Z direction, showing the macrocirculation of ink. Figure 1(b) is a cross-sectional view along line AA of Figure 1(a) as seen from the first direction X, showing the microcirculation and macrocirculation of ink. Figure 1(c) is an enlarged view of part B of Figure 1(a), showing the microcirculation of ink. The liquid discharge head 100 includes a substrate 1, a discharge port forming member 2 provided on the substrate 1, and a flow path member 3 located on the opposite side of the discharge port forming member 2 and supporting the substrate 1. The substrate 1 is a parallelogram that is longer in the first direction X and shorter in the second direction Y. A plurality of individual flow paths 4 are formed between the substrate 1 and the discharge port forming member 2. The discharge port forming member 2 has a discharge port 5 that communicates with the individual flow paths 4 and discharges ink. An energy generating element 6 is formed on the substrate 1 at a position opposite the ejection port 5, which provides energy to the ink for ejection. A recirculation element 7 is also formed on the substrate 1, which provides energy to the ink for microcirculation (described later). The energy generated by the recirculation element 7 is not large enough to eject the ink. Electrothermal conversion elements and piezoelectric elements can be used as the energy generating element 6 and the recirculation element 7.

[0012] The individual flow channels 4 are provided on the first surface 1A of the substrate 1 and are channels through which ink is recirculated. The individual flow channels 4 have a roughly U-shape, with a recirculation element 7 on the upstream side and an energy generation element 6 on the downstream side. A partition wall 16 is provided between the energy generation element 6 and the recirculation element 7. Multiple individual flow channels 4 form a flow channel row 31 extending in a first direction X, and accordingly, the discharge ports 5 form a discharge port row 32 extending in the first direction X. In Figure 1(a), four individual flow channels 4 are arranged in the first direction X, but in reality, more individual flow channels 4 are arranged in the first direction X. In this embodiment, two flow channel rows 31 are provided. On the first surface 1A of the substrate 1, a connection area 8 is provided that communicates with the inlets 41 and outlets 42 of the multiple individual flow channels 4. The connection area 8 is arranged in a second direction Y, adjacent to the inlets 41 and outlets 42 of the multiple individual flow channels 4. A filter member 19 is provided in front of the outlet 42.

[0013] When the energy generating element 6 is not driven (when ink is not being ejected), ink that enters the individual channel 4 from the connection region 8 through the inlet 41 is driven by the recirculation element 7, passes through the energy generating element 6, and flows out to the connection region 8 from the outlet 42. This creates microcirculation C1 in the individual channel 4. Microcirculation C1 is a minute circulation of ink within each individual channel 4 unit caused by the recirculation element 7. That is, microcirculation C1 occurs in each individual channel 4, which includes one ejection port 5, one energy generating element 6, and one recirculation element 7. When ink is not being ejected, the concentrated ink that has thickened due to evaporation from the ejection port 5 flows out from the outlet 42 of the individual channel 4 by microcirculation C1. This replaces the concentrated ink near the ejection port 5 with fresh ink, thereby suppressing clogging of the ejection port 5.

[0014] The substrate 1 has a supply through-hole 9 and a recovery through-hole 10 that penetrate through the substrate 1. The supply through-hole 9 and the recovery through-hole 10 penetrate the substrate 1 from the first surface 1A to the second surface 1B. Viewed from the Z direction, the supply through-hole 9 and the recovery through-hole 10 are located in the connection region 8. The flow channel member 3 is provided with a supply channel 11 and a recovery channel 12 facing the second surface 1B of the substrate 1. The supply channel 11 is connected to the supply through-hole 9, and the recovery channel 12 is connected to the recovery through-hole 10. Viewed from the Z direction, the supply channel 11 and the recovery channel 12 are separated from each other by a partition wall 13 provided between the supply through-hole 9 and the recovery through-hole 10. The partition wall 13 extends linearly in the first direction X, but its shape is not limited as long as the supply channel 11 and the recovery channel 12 can be separated. With the above configuration, the connection region 8, supply through-hole 9, recovery through-hole 10, supply channel 11, and recovery channel 12 form ink circulation channels 8-12. Ink flows into the first surface 1A of the substrate 1 through the supply channel 11 and supply through-hole 9, and flows through the connection region 8 of the first surface 1A, then through the recovery through-hole 10 and recovery channel 12 in that order. The supply through-hole 9 supplies ink to the connection region 8, and further supplies ink to the multiple individual channels 4 via the connection region 8. The recovery through-hole 10 recovers ink from the connection region 8. In other words, the recovery through-hole 10 recovers ink from the multiple individual channels 4 via the connection region 8.

[0015] Thus, circulation channels 8-12 are channels that communicate with multiple individual channels 4 and recirculate ink. The ink circulation that occurs in circulation channels 8-12 is called macrocirculation C2. Macrocirculation C2 is a circulation over a larger range than microcirculation C1. As will be described later, macrocirculation C2 does not necessarily need to supply ink to individual channels 4, but it is configured to recirculate the ink flowing out of individual channels 4. Macrocirculation C2 is generated by recirculation elements for macrocirculation provided in circulation channels 8-12, and by circulation pumps (neither shown) provided outside the substrate 1.

[0016] Multiple supply through-holes 9 and multiple recovery through-holes 10 are provided in the first direction X, forming a supply through-hole row 33 and a recovery through-hole row 34. In Figure 1(a), two supply through-holes 9 and two recovery through-holes 10 are arranged in the first direction X, but in reality, more supply through-holes 9 and recovery through-holes 10 are arranged in the first direction X. The supply through-hole row 33 and the recovery through-hole row 34 are located between two flow path rows 31 in the second direction Y, and the flow path rows 31 are provided on both sides of the supply through-hole row 33 and the recovery through-hole row 34 in the second direction Y. That is, a pair of through-hole rows 33, 34 are shared by the two flow path rows 31 that are combined with them. This reduces the number of through-hole rows 33, 34. Each supply through-hole 9 and its corresponding recovery through-hole 10 are adjacent to each other in the second direction Y, and the macrocirculation C2 flows mainly from each supply through-hole 9 towards the corresponding recovery through-hole 10. Therefore, in connection region 8, macrocirculation C2 occurs approximately in the second direction Y.

[0017] Here, a comparative example will be described with reference to FIG. 7. FIG. 7 is a schematic diagram for explaining in detail the vicinity of the discharge port 5 of the liquid discharge head 101 of the comparative example. FIG. 7(a) is a plan view of the liquid discharge head 101 viewed from the Z direction, and FIG. 7(b) is a cross-sectional view taken along the line A-A of FIG. 7(a) viewed from the first direction X. In the comparative example, due to the microcirculation C1 in the individual flow path 4, as indicated by the arrow C3, there is a possibility that the concentrated ink flowing out from the outlet 42 of the individual flow path 4 may flow back into the individual flow path 4 from the inlet 41 of the individual flow path 4. Due to this recirculation of the concentrated ink, there is a possibility that the concentrated ink in the individual flow path 4 may not be efficiently replaced by fresh ink. This problem can be solved, for example, by arranging the inlet 41 away from the outlet 42 as in the fourth to sixth embodiments. However, when discharging ink, ink flows into the individual circuit from both the inlet 41 and the outlet 42, so there is a possibility that the concentrated ink may flow backward into the individual flow path 4. That is, even if the inlet 41 is arranged away from the outlet 42, there is a possibility of discharge failure or printing failure due to the concentrated ink during ink discharge. These problems are caused by the concentrated ink flowing out from the outlet 42 of the individual flow path 4 flowing back into the individual flow path 4 through at least one of the inlet 41 and the outlet 42. Therefore, it is desirable to discharge the concentrated ink flowing out from the outlet 42 of the individual flow path 4 to the connection region 8 without flowing it into the individual flow path 4 from the connection region 8.

[0018] One of the causes of the above problems in the comparative example is that the individual flow path 4 that performs the microcirculation C1 and the circulation flow path that performs the macrocirculation C2 communicate with each other only through the through-hole 109 of the substrate 1. Since the microcirculation C1 occurs only on the first surface 1A side of the substrate 1 and the macrocirculation C2 occurs only on the second surface 1B side of the substrate 1, the effect of replacing the concentrated ink in the individual flow path 4 with fresh ink by the macrocirculation C2 is limited. Therefore, the concentrated ink flowing out from the outlet 42 of the individual flow path 4 cannot be efficiently discharged from the connection region 8. On the other hand, in the present embodiment, since the supply flow path 11 and the recovery flow path 12 are separated from each other by the partition wall 13, the macrocirculation C2 flows through the supply through-hole 9 to the connection region 8 on the first surface 1A of the substrate 1, that is, near the outlet 42 of the individual flow path 4. In other words, the macrocirculation C2 flows at the same level as the microcirculation C1 in the Z direction. The concentrated ink flowing out from the individual flow path 4 to the connection region 8 by the microcirculation C1 is efficiently discharged from the connection region 8 by the macrocirculation C2, and the individual flow path 4 is replaced with fresh ink. Since the concentrated ink is less likely to stay in the connection region 8, the possibility of the concentrated ink flowing backward from the connection region 8 to the individual flow path 4 during ink ejection is also reduced. Thereby, the influence of the concentrated ink flowing out from the outlet 42 of the individual flow path 4 can be reduced. In the present embodiment, the recirculation element 7 is an electrothermal conversion element. However, when a piezo element is used, depending on its driving method, the inlet 41 and the outlet 42 of the individual flow path 4 may be opposite to those in the present embodiment. In this case, the same configuration as in the present embodiment can be applied.

[0019] (Second Embodiment) FIG. 2 is a schematic diagram for explaining in detail the vicinity of the discharge port 5 of the liquid discharge head 100 according to the second embodiment. FIG. 2(a) is a plan view of the liquid discharge head 100 as viewed from the Z direction, FIG. 2(b) is a cross-sectional view taken along the line A-A of FIG. 2(a) as viewed from the first direction X, and FIG. 2(c) is a cross-sectional view taken along the line B-B of FIG. 2(a) as viewed from the first direction X. FIGS. 2(b) and 2(c) show the microcirculation C1 and the macrocirculation C2 of the ink. Hereinafter, the description will focus on the differences from the first embodiment. The configurations and effects for which the description is omitted are the same as those in the first embodiment.

[0020] The supply through-hole 9 and the recovery through-hole 10 work together to form a row of through-holes 35 extending in a first direction X. The supply through-holes 9 and the recovery through-holes 10 are arranged alternately in the first direction X, and the macrocirculation C2 flows between the supply through-holes 9 and the recovery through-holes 10 in the first direction X. The flow path rows 31 are provided on both sides of the through-hole row 35 in a second direction Y. That is, one row of through-holes 35 is combined with two flow path rows 31. The circulation flow paths 8-12 have a connection region 8, a supply through-hole 9, a recovery through-hole 10, a supply flow path 11, and a recovery flow path 12. The supply through-hole 9 and the recovery flow path 12 face the second surface 1B of the substrate 1 and communicate with the supply flow path 11 and the recovery through-hole 10, respectively. The partition wall 13 separating the supply channel 11 and the recovery channel 12 extends in a meandering manner along the periphery of the supply through-hole 9 and the recovery through-hole 10 when viewed from the Z direction. The supply through-hole 9 is connected to the supply channel 11 by a supply connection channel 14 that branches off from the supply channel 11 in a comb-like manner and extends in a second direction Y. Similarly, the recovery through-hole 10 is connected to the recovery channel 12 by a recovery connection channel 15 that branches off from the recovery channel 12 in a comb-like manner and extends in a second direction Y.

[0021] In the first embodiment, the macrocirculation C2 flows in the connection region 8 mainly in the second direction Y between the supply through-hole row 33 and the recovery through-hole row 34. In contrast, in this embodiment, the macrocirculation C2 flows in the first direction X in the connection region 8, and the ink flow is particularly dominant in the region along the through-hole row 35. As a result, the macrocirculation C2 can flow in a region close to the outlet 42 of the individual channel 4. Because the supply through-holes 9 and recovery through-holes 10 are arranged alternately, the macrocirculation C2 flows more uniformly in the second direction Y. For these reasons, the concentrated ink that has leaked out from the outlet 42 of the individual channel 4 can be discharged from the connection region 8 more efficiently. In addition, in this embodiment, because the supply through-holes 9 and recovery through-holes 10 are arranged alternately, only one row of through-hole row 35 is needed. Therefore, compared to the first embodiment, the space between the through-holes and the rows of through-holes is reduced, and the dimensions of the liquid discharge head 100 in the second direction Y can be reduced.

[0022] (Third embodiment) Figure 3 is a schematic diagram illustrating in detail the vicinity of the discharge port 5 of the liquid discharge head 100 of the third embodiment. Figure 3(a) is a plan view of the liquid discharge head 100 as seen from the Z direction, Figure 3(b) is a cross-sectional view along line AA of Figure 3(a) as seen from the first direction X, and Figure 3(c) is a cross-sectional view along line BB of Figure 3(a) as seen from the first direction X. Figures 3(b) and 3(c) show the microcirculation C1 and macrocirculation C2 of the ink. The following description will focus on the differences from the second embodiment. Configurations and effects that are not described are the same as in the first and second embodiments. Multiple through-hole rows 35 are provided, and flow path rows 31 are provided on both sides of each through-hole row 35 in the second direction Y. That is, one row of through-hole rows 35 is combined with two flow path rows 31. The supply connection flow path 14 branches off from the supply flow path 11 in a comb-like manner and extends in the second direction Y. The supply connection channel 14 is connected to each supply through-hole 9 in a plurality of (two in this embodiment) rows of through-holes 35 that are at the same position in the first direction X. Similarly, the recovery connection channel 15 branches off from the recovery channel 12 in a comb-like manner and extends in the second direction Y. The recovery connection channel 15 is connected to each recovery through-hole 10 in a plurality of (two in this embodiment) rows of through-holes 35 that are at the same position in the first direction X. The number of rows of through-holes 35 is not limited to two; three or more rows of through-holes 35 can be provided. Since multiple rows of through-holes 35 can be provided between one supply channel 11 and one recovery channel 12, the number of discharge port rows 32 combined with them can also be increased. Therefore, many discharge ports 5 can be provided while keeping the dimensions of the liquid discharge head 100 in the second direction Y to a minimum.

[0023] (Fourth embodiment) Figure 4 is a schematic diagram illustrating in detail the vicinity of the discharge port 5 of the liquid discharge head 100 of the fourth embodiment. Figure 4(a) is a plan view of the liquid discharge head 100 as seen from the Z direction, Figure 4(b) is a cross-sectional view along line AA in Figure 4(a) as seen from the first direction X, and Figure 4(c) is a cross-sectional view along line BB in Figure 4(a) as seen from the first direction X. Figures 4(b) and 4(c) show the micro-circulation C1 and macro-circulation C2 of the ink. The following explanation will focus on the differences from the first embodiment. Configurations and effects that are not explained are the same as in the first embodiment.

[0024] The inlet 41 of the individual channel 4 is connected to another connection region 8A, which is different from the connection region 8. Rows of through-holes 35 and 36, which are combined with the individual channel 4, are provided on both sides of the individual channel 4. Row 35 of the through-holes is located in the connection region 8, and row 36 of the through-holes is located in the other connection region 8A. The other connection region 8A is provided only with supply through-holes 9, and does not have recovery through-holes 10. In other words, row 36 of the through-holes consists only of supply through-holes 9, and the other connection region 8A is connected to a supply channel 17 in which the ink does not recirculate. The supply channel 17 and the supply channel 11 are separated from each other by a partition wall 18. Unlike the first to third embodiments, the microcirculation C1 flows between different connection regions 8 and 8A.

[0025] The configuration of the connection region 8 is the same as in the second embodiment. The supply through-holes 9 and the recovery through-holes 10 are arranged alternately in the first direction X, forming a row of through-holes 35 extending in the first direction X. In the connection region 8, the macrocirculation C2 flows in the first direction X between the supply through-holes 9 and the recovery through-holes 10. The supply through-holes 9 are connected to the supply channel 11 by a supply connection channel 14 that branches off from the supply channel 11 in a comb-like manner and extends in the second direction Y. Similarly, the recovery through-holes 10 are connected to the recovery channel 12 by a recovery connection channel 15 that branches off from the recovery channel 12 in a comb-like manner and extends in the second direction Y.

[0026] When the inlet 41 and outlet 42 of an individual flow path 4 are connected to different connection regions 8, 8A, sufficient effect can be obtained by performing macro circulation C2 only in the connection region 8 connected to the outlet 42. Therefore, according to this embodiment, it is possible to rationalize the pump for macro circulation C2. However, in order to prevent concentrated ink from flowing from the connection region 8 into the individual flow path 4, it is preferable that the pressure at the inlet 41 be higher than the pressure at the outlet 42. This can be achieved by controlling the pressure of the pump that supplies ink to the supply flow path 17. Since each individual flow path 4 extends linearly in the second direction Y, it has excellent arrangement efficiency. However, as long as the inlet 41 and outlet 42 are connected to different connection regions 8, the shape of the individual flow path 4 is not limited in any way and may be curved or bent. In this embodiment, the discharge ports 5 can be arranged linearly in the first direction X. However, as shown in Figure 5(d), discharge ports 5A and 5B of different sizes can be shifted in the second direction Y and arranged in the first direction X as separate rows. Although not shown in the illustration, a configuration comprising the supply through-hole row 33 and the recovery through-hole row 34 shown in the first embodiment is also applicable to this embodiment.

[0027] (Fifth embodiment) Figure 5 is a schematic diagram illustrating in detail the vicinity of the discharge port 5 of the liquid discharge head 100 in the fifth embodiment. Figure 5(a) is a plan view of the liquid discharge head 100 as seen from the Z direction, Figure 5(b) is a cross-sectional view along line AA in Figure 5(a) as seen from the first direction X, and Figure 5(c) is a cross-sectional view along line BB in Figure 5(a) as seen from the first direction X. Figures 5(b) and 5(c) show the microcirculation C1 and macrocirculation C2 of the ink. The following description will focus on the differences from the fourth embodiment. Configurations and effects that are not described are the same as in the first and fourth embodiments. In this embodiment, flow path rows 31 combined with the through-hole row 35 are provided on both sides of the through-hole row 35 in the second direction Y. The other configurations are the same as in the fourth embodiment. Since one through-hole row 35 is shared by two flow path rows 31, many discharge ports 5 can be provided while keeping the dimensions of the liquid discharge head 100 in the second direction Y to a minimum. Although not shown in the illustration, a configuration comprising the supply through-hole row 33 and the recovery through-hole row 34 shown in the first embodiment is also applicable to this embodiment.

[0028] (Sixth embodiment) Figure 6 is a schematic diagram illustrating in detail the vicinity of the discharge port 5 of the liquid discharge head 100 of the sixth embodiment. Figure 6(a) is a plan view of the liquid discharge head 100 as seen from the Z direction, Figure 6(b) is a cross-sectional view along line AA of Figure 6(a) as seen from the first direction X, and Figure 6(c) is a cross-sectional view along line BB of Figure 6(a) as seen from the first direction X. Figures 6(b) and 6(c) show the microcirculation C1 and macrocirculation C2 of the ink. The following description will focus on the differences from the fifth embodiment. Configurations and effects that are not described are the same as in the fourth and fifth embodiments. In this embodiment, as in the fourth and fifth embodiments, the inlet 41 of the individual flow path 4 is connected to another connection area 8A different from the connection area 8. Multiple through-hole rows 35 are provided, and flow path rows 31 combined with the through-hole rows 35 are provided on both sides of the central through-hole row 35 in the second direction Y. In the connection regions 8, 8A on both sides, which are combined with the individual flow paths 4, a series of through-holes 35 is provided, in which supply through-holes 9 and recovery through-holes 10 are alternately arranged in the second direction Y. Unlike the fourth and fifth embodiments, the other connection regions 8A are connected to the circulation flow paths 8-12.

[0029] Similar to the third embodiment, the supply connection channel 14 branches off from the supply channel 11 in a comb-like manner and extends in the second direction Y. The supply connection channel 14 is connected to each supply through-hole 9 in a plurality of (three in this embodiment) through-hole rows 35 that are at the same position in the first direction X. Similarly, the recovery connection channel 15 branches off from the recovery channel 12 in a comb-like manner and extends in the second direction Y. The recovery connection channel 15 is connected to each recovery through-hole 10 in a plurality of (three in this embodiment) through-hole rows 35 that are at the same position in the first direction X. The number of through-hole rows 35 is not limited to three. In this embodiment as well as in the third embodiment, multiple through-hole rows 35 can be provided between one supply channel 11 and one recovery channel 12, so the number of discharge port rows 32 combined with them can also be increased. Therefore, many discharge ports 5 can be provided while keeping the dimensions of the liquid discharge head 100 in the second direction Y to a minimum. [Explanation of symbols]

[0030] 2 circuit boards 4 Individual channel 8 connection areas 9 Supply through hole 10 Recovery through-hole

Claims

1. A substrate having a first surface, a plurality of individual flow paths provided on the first surface of the substrate, the individual flow paths communicating with the liquid ejection ports and each having an inlet and an outlet; a substrate having a supply through hole penetrating the substrate and supplying liquid to the inlet, and a recovery through hole penetrating the substrate and recovering liquid from the outlet; a supply flow passage that supplies liquid to the supply through hole, and a recovery flow passage that recovers liquid from the recovery through hole; A liquid ejection head having a circulation flow path through which liquid flows in the order of the supply flow path, the supply through hole, a connection area provided on the first surface of the substrate and communicating with the outlet of the individual flow path, the recovery through hole, and the recovery flow path.

2. A liquid ejection head as described in claim 1, having a flow path member provided with the supply flow path and the recovery flow path and connected to a second surface which is the rear surface of the first surface.

3. The plurality of individual flow paths have a flow path array arranged in a first direction, The liquid ejection head according to claim 1 , wherein the supply flow path and the recovery flow path extend in the first direction.

4. The liquid ejection head according to claim 1 , wherein the individual flow paths have a flow path array arranged in a first direction, and the supply through hole and the recovery through hole are adjacent to each other in a second direction perpendicular to the first direction.

5. A liquid ejection head as described in claim 4, wherein the supply flow path and the recovery flow path are separated from each other by a partition provided between the supply through hole and the recovery through hole when viewed in a direction perpendicular to the substrate.

6. The liquid ejection head according to claim 1 , further comprising a flow path row in which the individual flow paths are arranged in a first direction, and a through hole row in which the supply through holes and the recovery through holes are arranged alternately in the first direction.

7. A liquid ejection head as described in claim 6, wherein the supply flow path and the recovery flow path are separated from each other by a partition that extends in a serpentine manner along the periphery of the supply through hole and the recovery through hole when viewed in a direction perpendicular to the substrate.

8. The supply flow path and the recovery flow path extend in the first direction, a supply connection flow path that branches off from the supply flow path, extends in a second direction perpendicular to the first direction, and connects the supply flow path and the supply through hole; The liquid ejection head according to claim 6 , further comprising: a recovery connection flow path that branches off from the recovery flow path, extends in the second direction, and connects the recovery flow path and the recovery through hole.

9. The liquid ejection head according to claim 6 , wherein the flow path arrays are provided on both sides of the through-hole array in a second direction perpendicular to the first direction.

10. The liquid ejection head according to claim 6 , wherein a plurality of rows of the through holes are provided.

11. The liquid ejection head according to claim 3 , wherein a plurality of the supply through holes and a plurality of the recovery through holes are provided in the first direction.

12. The liquid ejection head according to claim 1 , wherein the inlets of the plurality of individual flow paths are connected to the connection region.

13. The liquid ejection head according to claim 1 , wherein the inlet of the individual flow path is connected to a second connection region provided on the first surface of the substrate, the second connection region being different from the connection region.

14. The liquid ejection head according to claim 13 , wherein each of the individual flow paths extends linearly.

15. 15. The liquid ejection head according to claim 13, wherein the second connection region is connected to a supply flow path in which the liquid does not recirculate.

16. The liquid ejection head according to claim 13 , wherein the second connection region is connected to the circulation flow path.

17. A substrate having a first surface and a second surface that is a reverse surface of the first surface; a plurality of individual flow paths provided on the first surface of the substrate and communicating with liquid ejection ports; two through holes penetrating the substrate near the plurality of individual flow paths; having A liquid ejection head in which microcirculation is performed in each individual flow path, and macrocirculation is performed in the flow path including the two through holes and the first surface.

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