Liquid discharge head and liquid discharge device

Abstract

To provide a liquid discharge head that can suppress degradation in recording quality, and to provide a liquid discharge device.SOLUTION: A liquid discharge head has a circulation efficiency J which is improved in a discharge port on a downstream side in a flow direction in a fluid channel.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a liquid ejection head that ejects liquid and a liquid ejection apparatus. [Background technology]

[0002] In a liquid ejection head that ejects liquid from an ejection port, the ink near the ejection port thickens as volatile components in the ink evaporate from the ejection port. One known method of preventing ink thickening is to circulate the ink supplied to the liquid ejection head through a circulation path.

[0003] Furthermore, in a liquid ejection head, a method of providing multiple rows of ejection ports is known as one of the means for increasing the density of the ejection ports. Patent Document 1 describes a liquid ejection head that ensures ejection characteristics while increasing density by providing a row of small ejection ports and a row of large ejection ports between a first supply port and a second supply port. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2013-078936 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, when the liquid is simply circulated between the supply ports in the configuration as in Patent Document 1, the ink concentrated at the upstream ejection port flows into the downstream ejection port, which causes a problem that the ink becomes even more concentrated at the downstream ejection port, which may affect the landing accuracy and reduce the recording quality.

[0006] Therefore, the present invention provides a liquid ejection head and a liquid ejection apparatus that can suppress the deterioration of recording quality that accompanies ink concentration. [Means for solving the problem]

[0007] Therefore, the liquid ejection head of the present invention is a liquid ejection head comprising: an ejection port forming member in which a plurality of ejection ports including a first and a second ejection port are formed as through-holes; a substrate on which a plurality of energy generating elements capable of generating energy for ejecting liquid from the plurality of ejection ports are arranged; and a flow path through which liquid flows from the first ejection port to the second ejection port between the ejection port forming member and the substrate, wherein, for any ejection port, the height of the flow path on the upstream side in the direction in which the liquid flows relative to the ejection port is defined as H [μm], the thickness of the ejection port in the ejection direction of the ejection port in the ejection port forming member is defined as P [μm], the length of the inner diameter of the ejection port in the direction in which the liquid flows is defined as W [μm], and the circulation efficiency J of the ejection port is defined as J=H -0.34 ×P -0.66 When the circulation efficiency is defined as ×W, the circulation efficiency of the second discharge port is higher than the circulation efficiency of the first discharge port. Effect of the Invention

[0008] According to the present invention, it is possible to provide a liquid ejection head and a liquid ejection apparatus capable of suppressing deterioration of recording quality. [Brief description of the drawings]

[0009] [Figure 1] FIG. 2 is a diagram showing a liquid ejection head. [Diagram 2] FIG. 1 is a cross-sectional view showing a typical liquid ejection head. [Diagram 3] FIG. 1 is a cross-sectional view showing a liquid ejection head having four ejection port rows. [Figure 4] 4A and 4B are diagrams illustrating an arrangement of ejection ports and a circulating flow in a liquid ejection head. [Diagram 5] FIG. 2 is a schematic diagram showing an arrangement of ejection ports in a liquid ejection head. [Figure 6] FIG. 2 is a schematic diagram showing an arrangement of ejection ports in a liquid ejection head. [Figure 7] FIG. 2 is a schematic diagram showing an arrangement of ejection ports in a liquid ejection head. [Figure 8] FIG. 2 is a schematic diagram showing an arrangement of ejection ports in a liquid ejection head. [Figure 9] FIG. 2 is a schematic diagram showing an arrangement of ejection ports in a liquid ejection head. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] (First embodiment) A first embodiment of the present invention will now be described with reference to the drawings.

[0011] Fig. 1(a) is an enlarged view of the vicinity of the ejection port of a liquid ejection head to which this embodiment can be applied, and Fig. 1(b) is a cross-sectional view taken along line Ib-Ib1 of Fig. 1(a). Fig. 1(c) is a view showing another example of the configuration of the liquid ejection head of this embodiment. The liquid ejection head of this embodiment includes an ejection port 11 for ejecting liquid (hereinafter also referred to as ink), a flow path 13 for supplying liquid to the ejection port 11, a supply flow path 15 for supplying liquid to the flow path 13, and an outflow flow path 16 for recovering liquid from the flow path 13. The ejection port 11 is provided as a through hole penetrating an orifice plate 19, and the supply flow path 15 and the outflow flow path 16 are provided so as to penetrate a substrate 18.

[0012] The outlet 11 is provided with an outlet 11a having a small diameter and an outlet 11b having a diameter larger than that of the outlet 11a. The outlets 11a form an outlet row 21 arranged in a direction intersecting with the circulating flow 17, and the outlets 11b form an outlet row 22 arranged in a direction intersecting with the circulating flow 17. Furthermore, the liquid ejection head is provided with an energy generating element 14 formed between the outlets in the flow path 13, which generates energy used to eject the liquid, and a filter (structure) 20 which suppresses the influence of pressure changes during ejection from affecting adjacent outlets.

[0013] An ink meniscus is formed at the ejection port 11, forming an ejection port interface 12 which is an interface between the ink and the atmosphere. By driving an electrothermal conversion element (heater) which is an energy generating element 14, bubbles are generated in the liquid and the liquid is ejected from the ejection port 11. In this embodiment, an example in which a heater is used as the energy generating element will be described, but the present invention is not limited to this, and various types of energy generating elements such as a piezoelectric element can be used.

[0014] In the liquid ejection head of this embodiment, a liquid path is formed in which liquid flows in the order of supply flow path 15, flow path 13, ejection port 11, flow path 13, and outflow flow path 16, and this liquid path becomes a circulating flow 17. In this embodiment, the energy generating element 14 is driven while ink is flowing in the flow path 13 to eject droplets from the ejection port 11. The speed of the circulating flow through the flow path 13 is, for example, about 1 to 100 mm / s, and even if an ejection operation is performed while ink is flowing, there is little effect on landing accuracy, etc.

[0015] In such a liquid ejection head, the liquid flows through a plurality of flow paths while being branched by the filter 20. In Fig. 1(a), path Ib-Ib1 and path Ib-Ib2 are shown by lines as examples of the paths.

[0016] In this way, in a liquid ejection head in which a liquid path that creates a circulating flow is formed, the reason for providing multiple rows of ejection ports 11 between supply flow path 15 and outlet flow path 16 is to increase the density of the ejection ports. By increasing the density of the ejection ports, the cost of the substrate (chip) on which the above components are arranged can be reduced compared to a liquid ejection head with the same number of ejection ports.

[0017] In order to increase the density of the ejection ports, it is necessary to arrange many ejection ports while suppressing the expansion of the chip size. In this case, when a configuration in which a supply flow path 15 and an outflow flow path 16 are arranged on both sides of one ejection port row is taken as a unit, the size of this unit is restricted by the physical limit of the arrangement density of the ejection energy generating element 14 and the ejection port 11. In addition, when it is attempted to provide N rows of ejection port rows, the chip requires a size N times larger than the unit. In contrast, if a configuration is adopted in which multiple ejection port rows are arranged between one set of a supply flow path 15 and an outflow flow path 16 as shown in FIG. 1, the chip size can be reduced more than the above. In this way, in order to increase the density of the ejection ports, it is effective to arrange multiple rows of ejection port rows between the supply flow path 15 and the outflow flow path 16 and arrange many ejection ports while suppressing the expansion of the chip size.

[0018] FIG. 2 is a cross-sectional view showing a typical liquid ejection head having a configuration in which a plurality of rows of ejection ports are provided between a supply flow path and an outflow flow path, and ink is circulated.

[0019] Generally, when the number of ejection port arrays is increased, effects such as uneven density at the start of printing due to ink concentration and an increase in the number of preliminary ejections to eliminate the concentration become more pronounced, but a configuration that generates a circulating flow suppresses these effects.

[0020] 2, two rows of ejection ports 26 and 27 are formed in the flow path 24 between the supply flow path 23 and the outflow flow path 25. The circulating flow 28 that flows into the ejection port row 26 close to the supply flow path 23 then flows into the ejection port row 27 close to the outflow flow path 25. The ink that flows into the ejection port row is concentrated because it comes into contact with the air at the ejection ports 29. In other words, the circulating flow 28 that flows into the ejection port row 27 is more concentrated than the circulating flow 28 that flows into the ejection port row 26, and the ejection port row 27 on the downstream side is affected by the concentration of ink.

[0021] Fig. 3 is a cross-sectional view showing a liquid ejection head having four nozzle rows between a supply flow path and an outflow flow path. In the liquid ejection head of Fig. 3, liquid flowing in from a supply flow path 34 flows through a flow path 35, and then flows through nozzle row 30, nozzle row 31, nozzle row 32, and nozzle row 33 in that order. As the liquid moves from upstream to downstream through each nozzle row, it becomes more concentrated. This is particularly noticeable near the boundary surface between the nozzle and the atmosphere, and the liquid concentration becomes higher near each nozzle. Concentration progresses toward the downstream side, with the liquid concentration being highest in the most downstream nozzle row.

[0022] In this way, in a liquid ejection head that circulates liquid, when multiple rows of ejection ports are provided between a supply flow path and an outflow flow path to achieve high density of ejection ports, the liquid may become concentrated in the downstream ejection port row. When the liquid becomes concentrated, the desired ejection state may not be obtained. Furthermore, this effect becomes greater the more rows of ejection ports between the supply flow path and the outflow flow path, and the more downstream the rows are.

[0023] Therefore, in this embodiment, a circulation efficiency J is defined as an index showing the ink replacement efficiency, and a configuration is adopted in which the circulation efficiency J is high in the ejection port array on the downstream side.

[0024] Here, the circulation efficiency J will be explained.

[0025] 4(a) and (b) are diagrams for explaining the circulation efficiency J, and are diagrams showing the arrangement of the ejection ports in the liquid ejection head and the circulating flow. In Fig. 4, the liquid flowing in from the supply flow path 44 flows through the ejection port array 40, the ejection port array 41, the ejection port array 42, and the ejection port array 43 in that order, and flows out from the outlet flow path 45. The ejection ports in the ejection port array 40, the ejection port array 41, the ejection port array 42, and the ejection port array 43 are arranged at a resolution of 600 dpi in the row direction (the vertical direction in Fig. 4).

[0026] FIG. 4(a) shows eight fluid paths, A-B1, A-B2, A-B3, A-B4, A-B5, A-B6, A-B7, and A-B8. FIG. 4(a) also shows A'-B3' as a line indicating a cross section. In the liquid ejection head, the circulating flow passes through the upstream nozzle row, and then branches off by a structure (filter) 20 provided between adjacent nozzles in the downstream row. The branched circulating flow further branches downstream. In this way, the circulating flow flowing through the liquid ejection head flows from upstream to downstream, repeatedly branching by the number of nozzle rows.

[0027] Fig. 4(b) shows a cross section taken along line A'-B3' in Fig. 4(a). As shown in Fig. 4(b), the height on the upstream side in the flow direction of the liquid in the flow path 46 is H [μm], and the thickness (length in the liquid discharge direction) of the discharge port forming member 51 that forms the discharge ports 47, 48, 49, 50 is P [μm]. Also, the length of the inner diameter of the discharge ports 47, 48, 49, 50 in the flow direction of the liquid in the flow path 46 is W [μm]. In this case, the circulation efficiency J is J=H ―0.34 ×P -0.66 ×W...(Formula 1) Let us assume that.

[0028] It was confirmed that the higher the circulation efficiency J, the higher the efficiency of liquid replacement at the ejection port, and the less likely the impact of increased viscosity on ejection. Furthermore, when there are multiple ejection port rows, the circulation efficiency J can be calculated for each ejection port in each ejection port row. Furthermore, when considering the replacement of liquid at the ejection port, the height of the flow path when the liquid flows into the ejection port has an effect. Therefore, for the height H of the flow path 46, the value of the upstream side, which is the side where the liquid flows into the flow path corresponding to the ejection port, is used with respect to the flow direction of the liquid in the flow path 46.

[0029] Returning to FIG. 1, in this embodiment, the circulation efficiency J in each nozzle row is adjusted by making the width of the nozzles provided on the upstream side different from the width of the nozzles provided on the downstream side in the circulation flow inside the liquid ejection head. As shown in FIG. 1(b), the width Wb of the nozzles 11b on the downstream side is made wider than the width Wa of the nozzles 11a on the upstream side, so that the circulation efficiency J of the nozzles 11b on the downstream side is higher than that of the nozzles 11a on the upstream side. In this configuration, the nozzles 11a and 11b have different ejection amounts, so there are two types of ejection amount Vd. With two types of ejection amount Vd, finer gradation expression is possible by the ejected ink droplets.

[0030] Hereinafter, a configuration in which the circulation efficiency J is increased by changing the width W at any outlet will be described, but other configurations in which the circulation efficiency J is increased can also be adopted. For example, as shown in FIG. 1(c), this can be achieved by changing the flow path height H and the outlet length P while making the outlet width W the same for outlets 11a and 11b and keeping the sum of the flow path height H and the outlet length P constant. In other words, the circulation efficiency J can also be increased by changing the flow path height H and the outlet length P while maintaining the relationship H1+P1=H2+P2. In such a configuration, the discharge volume Vd from each outlet is the same, so the circulation efficiency J of the downstream nozzle can be increased with a configuration of one type of discharge volume Vd.

[0031] It was also confirmed that by setting the circulation efficiency J>1.7 at the outlet used for ejection, the liquid replacement efficiency is good and the ejection is less affected by thickening. Furthermore, in order to maintain good replacement efficiency, it is desirable that the liquid flow speed in the flow path 13 is 1 to 100 [mm / s].

[0032] Furthermore, it is sufficient that the circulation efficiency J of the discharge port corresponding to at least one or more flow paths is higher on the downstream side than on the upstream side.

[0033] By increasing the circulation efficiency J in the downstream discharge port row as in this embodiment, it is possible to suppress the progress of liquid concentration in the downstream discharge port row. Here, with respect to the substantial deterioration of the circulation efficiency J on the downstream side, a configuration in which the circulation efficiency J is increased as much as possible and made constant in all the discharge port rows can also be considered. However, when the circulation efficiency J is increased as much as possible, since the evaporated and concentrated ink flows efficiently to the downstream side, the concentration of the entire ink tends to progress. Therefore, it is not simply desirable to increase the circulation efficiency J, but it is desirable to keep it at a necessary value.

[0034] In this way, the circulation efficiency J at the downstream discharge port in the flow direction in the flow path is made higher than the circulation efficiency J at the upstream discharge port. Thereby, it is possible to provide a liquid discharge head and a liquid discharge device that can suppress a decrease in recording quality.

[0035] (Second Embodiment) Hereinafter, a second embodiment of the present invention will be described with reference to the drawings. Since the basic configuration of this embodiment is the same as that of the first embodiment, the characteristic configuration will be described below.

[0036] FIG. 5 is a schematic diagram showing the arrangement of discharge ports in the liquid discharge head of this embodiment. The liquid discharge head of this embodiment includes four discharge port rows 52, 53, 54, and 55. Further, the four discharge port rows 52, 53, 54, and 55 are such that the upstream two discharge port rows 52 and 53 through which the circulating flow flows have small-diameter discharge ports, and the downstream two discharge port rows 54 and 55 have large-diameter discharge ports. That is, the discharge port diameters are configured to be small, small, large, and large in order from upstream to downstream. Expressing this in terms of the relationship of the circulation efficiency, it satisfies the relationship of "J1 = J2 < J3 = J4" in order from the upstream discharge port.

[0037] Advantages of this configuration include that there are two discharge port rows 52 and 53 each having a small-diameter discharge port and two discharge port rows 54 and 55 each having a large-diameter discharge port, and the resolution of each discharge port row is increased. Another two points are that the circulation efficiency J is increased in the downstream two rows that are easily affected by concentration.

[0038] (Third Embodiment) Hereinafter, a third embodiment of the present invention will be described with reference to the drawings. Since the basic configuration of this embodiment is the same as that of the first embodiment, the characteristic configuration will be described below.

[0039] FIG. 6 is a schematic diagram showing the arrangement of ejection ports in the liquid ejection head of this embodiment. The liquid ejection head of this embodiment includes four ejection port rows 60, 61, 62, and 63. Also, the ejection port row 60 at the most upstream of the circulation flow includes small-diameter ejection ports, the ejection port row 61 includes medium-diameter ejection ports larger than the small diameter, the ejection port row 62 includes large-diameter ejection ports larger than the medium diameter, and the ejection port row 63 at the most downstream includes extremely large-diameter ejection ports larger than the large diameter. That is, the ejection port diameters are configured to be in the order of small, medium, large, and extremely large from upstream to downstream. Expressing this in terms of the relationship of circulation efficiency, it satisfies the relationship of "J1 < J2 < J3 < J4" in order from the ejection ports on the upstream side.

[0040] As an advantage of this configuration, since there are four types of ejection amounts, finer gradation expression becomes possible with the ejected ink droplets. Furthermore, it can be mentioned that the circulation efficiency J gradually increases toward the downstream, which is more susceptible to the influence of concentration.

[0041] (Fourth Embodiment) Hereinafter, a fourth embodiment of the present invention will be described with reference to the drawings. Since the basic configuration of this embodiment is the same as that of the first embodiment, the characteristic configuration will be described below.

[0042] FIG. 7 is a schematic diagram showing the arrangement of discharge ports in the liquid discharge head of the present embodiment. The liquid discharge head of the present embodiment includes four discharge port rows 70, 71, 72, and 73. Further, the discharge port row 70 at the most upstream of the circulation flow includes large-diameter discharge ports, the discharge port row 71 includes small-diameter discharge ports, the discharge port row 72 includes small-diameter discharge ports, and the discharge port row 73 at the most downstream includes large-diameter discharge ports. That is, the discharge port diameters are configured in the order of large, small, small, and large from upstream to downstream. When this is expressed in terms of the relationship of circulation efficiency, it satisfies the relationship of "J1>J2=J3<J4, J1=J4" in order from the discharge ports on the upstream side.

[0043] As an advantage of this configuration, the circulation efficiency J can be increased from the center to the most downstream, and the circulation efficiency J can be made the highest in the most downstream row where the concentration effect is most pronounced. The discharge amount from the liquid discharge head also becomes symmetric left and right, and droplet formation becomes uniform.

[0044] (Fifth Embodiment) Hereinafter, a fifth embodiment of the present invention will be described with reference to the drawings. Since the basic configuration of this embodiment is the same as that of the first embodiment, the characteristic configuration will be described below.

[0045] FIG. 8 is a schematic diagram showing the arrangement of discharge ports in the liquid discharge head of the present embodiment. The liquid discharge head of the present embodiment includes four discharge port rows 80, 81, 82, and 83. Further, the discharge port row 80 at the most upstream of the circulation flow includes small-diameter discharge ports, the discharge port row 81 includes large-diameter discharge ports, the discharge port row 82 includes small-diameter discharge ports, and the discharge port row 83 at the most downstream includes large-diameter discharge ports. That is, the discharge port diameters are configured in the order of small, large, small, and large from upstream to downstream. When this is expressed in terms of the relationship of circulation efficiency, it satisfies the relationship of "J1<J2, J3<J4, J1=J3, J2=J4" in order from the discharge ports on the upstream side.

[0046] As an advantage of this configuration, it can be mentioned that the circulation efficiency J is the highest in the most downstream column where the concentration effect is most prominent on the downstream side. Further, in the direction of the flow of the circulation flow, since the small-diameter discharge ports are not adjacent and the large-diameter discharge ports are not adjacent, the crosstalk phenomenon that affects the discharge of adjacent discharge ports during discharge is suppressed in the X direction.

[0047] (Other Embodiments) The configuration of FIG. 1(b) and the configuration of FIG. 1(c) may be combined.

[0048] For example, in FIG. 5 (Second Embodiment) and FIG. 8 (Fifth Embodiment), by adjusting H and P of each discharge port row, it is possible to achieve "J1 < J2 < J3 < J4".

[0049] Also, in each of the above embodiments, although the configuration in which one long-hole-shaped supply channel 15 and one outflow channel 16 are provided in the liquid discharge head has been described, the present invention is not limited to this. That is, a configuration in which the long hole is partitioned by a plurality of walls to form a plurality of supply channels 15 and the long hole is partitioned by a plurality of walls to form a plurality of outflow channels 16 may also be used.

[0050] (Modification) Hereinafter, a modification of the present invention will be described with reference to the drawings. Since the basic configuration of this modification is the same as that of the first embodiment, the characteristic configuration will be described below.

[0051] FIG. 9 is a schematic diagram showing the arrangement of discharge ports in the liquid discharge head of this modification. The liquid discharge head of this modification includes four discharge port rows 90, 91, 92, and 93. In this modification, in the Y direction (the discharge port arrangement direction in each discharge port row), discharge ports of the same size are not adjacent to each other. And in a part of the flow in the circulation flow, the discharge port diameters are configured to be small, small, large, and large in order from upstream to downstream. When this is expressed in terms of the relationship of circulation efficiency, it satisfies the relationship of "J1 = J2 < J3 = J4" in order from the upstream discharge port. Note that in this modification, in addition to the discharge port arrangement shown here, a combination of a plurality of arrangements is also conceivable.

[0052] The advantages of this configuration include the case where the circulation efficiency is improved downstream relative to the upstream side. Furthermore, since small-diameter outlets are not adjacent to each other in the Y direction and large-diameter outlets are not adjacent to each other in the Y direction, crosstalk, which affects the discharge of adjacent outlets during discharge, is suppressed in the Y direction.

[0053] In the above-mentioned embodiments and modified examples, the liquid ejection head has no flow path walls that form individual pressure chambers, and ejection ports are arranged in large numbers at high density. In the case of such a configuration, although it has the characteristic of extremely high refill performance, there is a concern that interference (crosstalk) between the ejection ports is strong. It is preferable to have a configuration that can avoid crosstalk as much as possible.

[0054] Furthermore, when the ink viscosity is high (viscosity η is approximately 8 cp), the crosstalk itself is reduced. On the other hand, when the ink viscosity is medium (viscosity η is approximately 4 cp), further measures to reduce crosstalk must be taken. In each of the above-described embodiments and modifications, a filter 20 (see FIG. 1) is disposed between the ejection openings in the ejection opening array. For example, as a further measure to reduce crosstalk, it is possible to place a filter between the ejection opening arrays as well. When the ink viscosity is medium, this configuration is more preferable.

[0055] The disclosure of this embodiment includes the following configuration.

[0056] (Configuration 1) a discharge port forming member in which a plurality of discharge ports including the first and second discharge ports are formed as through-holes; a substrate on which a plurality of energy generating elements capable of generating energy for discharging liquid from the plurality of discharge ports are arranged; a flow path through which liquid flows from the first discharge port to the second discharge port between the discharge port forming member and the substrate; A liquid ejection head comprising: At any outlet, The height of the flow path on the upstream side of the discharge port in the direction in which the liquid flows is H [μm]. In the discharge port forming member, the thickness in the discharge direction of the discharge port is P [μm], the length of the inner diameter in the liquid flow direction of the discharge port is W [μm], when the circulation efficiency J of the discharge port is defined as J = H -0.34 ×P -0.66 ×W, a liquid discharge head characterized in that the circulation efficiency of the second discharge port is higher than that of the first discharge port.

[0057] (Configuration 2) a discharge port row in which the plurality of discharge ports are arranged in a direction intersecting the liquid flow direction, a supply flow path for supplying liquid to the flow path, an outflow flow path for allowing liquid to flow out from the flow path, the liquid discharge head according to Configuration 1, further comprising:

[0058] (Configuration 3) including four of the discharge port rows between the supply flow path and the outflow flow path, the liquid discharge head according to Configuration 2, characterized in that when the circulation efficiency J is J1, J2, J3, J4 from the discharge port on the upstream side in the liquid flow, the relationship J1 = J2 < J3 = J4 is satisfied.

[0059] (Configuration 4) including four of the discharge port rows between the supply flow path and the outflow flow path, the liquid discharge head according to Configuration 2, characterized in that when the circulation efficiency J is J1, J2, J3, J4 from the discharge port on the upstream side in the liquid flow, the relationship J1 < J2 < J3 < J4 is satisfied.

[0060] (Configuration 5) including four of the discharge port rows between the supply flow path and the outflow flow path, The liquid discharge head according to Configuration 2, wherein when the circulation efficiency J is J1, J2, J3, J4 from the discharge port on the upstream side in the liquid flow, the relationship J1>J2 = J3<J4, J1 = J4 is satisfied.

[0061] (Configuration 6) Between the supply flow path and the outflow flow path, the four discharge port columns, A structure serving as a filter is provided between adjacent discharge ports in the discharge port column, In a plurality of flow paths formed by the liquid flow being branched by the filter, the discharge ports corresponding to at least one or more of the flow paths have a higher circulation efficiency J on the downstream side than on the upstream side, which is the liquid discharge head according to Configuration 2.

[0062] (Configuration 7) The liquid discharge head according to any one of Configurations 1 to 6, wherein the circulation efficiency J is changed by changing the length W.

[0063] (Configuration 8) The liquid discharge head according to any one of Configurations 1 to 7, wherein the circulation efficiency J at the discharge port satisfies J>1.7.

[0064] (Configuration 9) The liquid discharge head according to any one of Configurations 1 to 8, wherein the velocity of the liquid flow in the flow path is 1 to 100 mm / s.

[0065] (Configuration 10) The discharge ports in the discharge port column are arranged at a resolution of 600 dpi, which is the liquid discharge head according to any one of Configurations 2 to 6.

[0066] (Configuration 11) The liquid discharge head according to any one of Configurations 3 to 6, comprising a structure serving as a filter between adjacent discharge port columns.

Explanation of Signs

[0067] 11 Discharge port 13 Flow Path 14 Energy generating element 15 Supply Channel 16 Outlet flow path 20 Filters 19 Discharge port forming member

Claims

1. a discharge port forming member in which a plurality of discharge ports including the first and second discharge ports are formed as through-holes; a substrate on which a plurality of energy generating elements capable of generating energy for ejecting liquid from the plurality of ejection ports are arranged; a flow path through which a liquid flows from the first discharge port to the second discharge port between the discharge port forming member and the substrate; A liquid ejection head comprising: At any outlet, The height of the flow path on the upstream side of the ejection port in the direction in which the liquid flows is H [μm]. The thickness of the ejection port forming member in the ejection direction of the ejection port is P [μm], The length of the inner diameter of the ejection port in the liquid flow direction is W [μm], The circulation efficiency J of the outlet is J=H -0.34 ×P -0.66 When defined as ×W, the circulation efficiency of the second outlet is higher than the circulation efficiency of the first outlet, the first ejection ports form a first ejection port array arranged in a direction intersecting the flow direction of the liquid, and a structure serving as a filter is provided between adjacent first ejection ports in the first ejection port array; The second ejection ports form a second ejection port row arranged in a direction intersecting the flow direction of the liquid, and the liquid ejection head is characterized in that a filter structure is provided between adjacent second ejection ports in the second ejection port row.

2. A supply flow path that supplies a liquid to the flow path; an outlet flow path for discharging liquid from the flow path; 2. The liquid ejection head according to claim 1, further comprising:

3. a third row of ejection ports arranged in a direction intersecting the flow direction of the liquid between the supply flow path and the outflow flow path, and a fourth row of ejection ports arranged in a direction intersecting the flow direction of the liquid, A liquid ejection head as described in claim 2, characterized in that when the circulation efficiency J is J1, J2, J3, and J4 in order from the ejection outlet in the ejection outlet row upstream in the liquid flow, the relationship J1 = J2 < J3 = J4 is satisfied.

4. a third row of ejection ports arranged in a direction intersecting the flow direction of the liquid between the supply flow path and the outflow flow path, and a fourth row of ejection ports arranged in a direction intersecting the flow direction of the liquid, A liquid ejection head as described in claim 2, characterized in that when the circulation efficiency J is J1, J2, J3, and J4 in order from the ejection outlet in the ejection outlet row upstream in the liquid flow, the relationship J1<J2<J3<J4 is satisfied.

5. a third row of ejection ports arranged in a direction intersecting the flow direction of the liquid between the supply flow path and the outflow flow path, and a fourth row of ejection ports arranged in a direction intersecting the flow direction of the liquid, A liquid ejection head as described in claim 2, characterized in that when the circulation efficiency J is J1, J2, J3, and J4 in order from the ejection outlet in the ejection outlet row upstream in the liquid flow, the relationship of J1 > J2 = J3 < J4 and J1 = J4 is satisfied.

6. a third row of ejection ports arranged in a direction intersecting the flow direction of the liquid between the supply flow path and the outflow flow path, and a fourth row of ejection ports arranged in a direction intersecting the flow direction of the liquid, a structure that functions as a filter also between adjacent ejection ports in the third ejection port array and the fourth ejection port array, 3. A liquid ejection head according to claim 2, wherein, in a plurality of flow paths formed by branching the flow of liquid by the filter, the circulation efficiency J of the ejection port corresponding to at least one of the flow paths is higher downstream than upstream.

7. 2. The liquid ejection head according to claim 1, wherein the circulation efficiency J is changed by changing the length W.

8. 2. The liquid ejection head according to claim 1, wherein the circulation efficiency J at the ejection port satisfies J>1.

7.

9. 2. A liquid ejection head according to claim 1, wherein the velocity of the liquid flowing through said flow path is 1 to 100 mm / s.

10. 2. The liquid ejection head according to claim 1, wherein the ejection ports in the first ejection port array are arranged at a resolution of 600 dpi.

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