Liquid dispensing head and liquid dispensing device

Abstract

The present invention provides a liquid discharge head and liquid discharge device that reduce the risk of bubbles accumulating in the flow path near the pressure chamber without increasing the size of the liquid discharge head and liquid discharge device. [Solution] A liquid discharge head having a plurality of discharge port rows, a plurality of pressure chambers, a plurality of common supply channels 111 extending along the direction of arrangement of the discharge port rows for supplying liquid to the plurality of pressure chambers, a plurality of common recovery channels 112 extending along the direction of arrangement of the discharge port rows for recovering liquid from the plurality of pressure chambers, a distribution channel 301 for distributing liquid to the plurality of common supply channels, and a consolidation channel 302 for consolidating liquid from the plurality of common recovery channels, wherein the liquid discharge head is characterized by comprising a circulation pump that circulates the liquid in the order of the distribution channels, the common supply channels, the pressure chambers, the common recovery channels, and the consolidation channels, and a bypass opening 123 that connects the common supply channels and the consolidation channels without going through the pressure chambers.

Description

[Technical Field]

[0001] This invention relates to a liquid dispensing head and a liquid dispensing device. [Background technology]

[0002] A liquid ejection device is equipped with a liquid ejection head for ejecting liquid, and achieves its desired purpose by ejecting liquid from the liquid ejection head. For example, in an inkjet recording device, the inkjet recording head, which is the liquid ejection head, is mounted on the carriage, and ink is ejected from the ejection element substrate of the inkjet recording head to record images, characters, etc. During the recording of images, characters, etc., the ejection port for ejecting liquid from the liquid ejection head is exposed to the outside air. Therefore, the liquid in the pressure chamber located near the ejection port, which applies pressure to the liquid ejected from the ejection port, may become viscous, potentially causing ejection failure.

[0003] Patent Document 1 describes a liquid discharge head equipped with a circulation pump for circulating liquid, which suppresses viscosity increase of the liquid near the pressure chamber by continuously circulating the liquid inside the liquid discharge head. In this configuration, since the liquid circulates inside the liquid discharge head without passing through the liquid discharge device, a flow path for recovering the liquid from the liquid discharge head to the liquid discharge device is unnecessary, making it possible to miniaturize the liquid discharge device. Furthermore, compared to the case where the liquid is circulated between the liquid discharge device and the liquid discharge head, the circulation path is smaller when circulating within the liquid discharge head, so it is possible to miniaturize the installed circulation pump and suppress the enlargement of the liquid discharge head equipped with the circulation pump. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2023-90627 [Overview of the project] [Problems that the invention aims to solve]

[0005] However, in the liquid discharge head described in Patent Document 1, the circulation pump installed in the liquid discharge head is small, resulting in low liquid delivery capacity and making it easy for bubbles to accumulate in the flow path near the pressure chamber. If bubbles are present near the pressure chamber, they may be drawn into the pressure chamber when the liquid is discharged, potentially causing discharge problems. To suppress this, a method of defogging by installing a degassing module in the liquid discharge head or the liquid discharge device body is known, but installing a degassing module increases the size of the liquid discharge head or liquid discharge device.

[0006] In view of the above problems, the present invention aims to provide a liquid discharge head and a liquid discharge device that reduce the risk of bubbles accumulating in the flow path near the pressure chamber without increasing the size of the liquid discharge head and liquid discharge device. [Means for solving the problem]

[0007] The liquid discharge head of the present invention comprises a plurality of discharge port rows arranged with a plurality of discharge ports for discharging liquid, a plurality of pressure chambers through which pressure acts on the liquid discharged from the plurality of discharge ports, a plurality of common supply channels extending along the direction of arrangement of the discharge port rows for supplying liquid to the plurality of pressure chambers, a plurality of common recovery channels extending along the direction of arrangement of the discharge port rows for recovering liquid from the plurality of pressure chambers, a distribution channel for distributing liquid to the plurality of common supply channels, and a consolidation channel for consolidating liquid from the plurality of common recovery channels. A liquid discharge head having a circulation pump that circulates the liquid in the order of the distribution channel, the common supply channel, the pressure chamber, the common recovery channel, and the aggregation channel, and a bypass opening that connects the common supply channel and the aggregation channel without going through the pressure chamber. [Effects of the Invention]

[0008] According to the present invention, an object is to provide a liquid ejection head and a liquid ejection device that reduce the risk of bubbles stagnating in a flow path near a pressure chamber without increasing the size of the liquid ejection head and the liquid ejection device.

Brief Description of the Drawings

[0009] [Figure 1] Schematic perspective view of the liquid ejection device. [Figure 2] Perspective view of the liquid ejection head. [Figure 3] Exploded perspective view of the liquid ejection head. [Figure 4] Schematic diagram showing ink circulation in the liquid ejection device. [Figure 5] Side view of the liquid ejection head. [Figure 6] Cross-sectional view of the liquid ejection head. [Figure 7] Enlarged cross-sectional view near the pressure adjustment mechanism. [Figure 8] Perspective view of the cover plate and the ejection element substrate. [Figure 9] Schematic diagram showing the connection relationship between the ejection element substrate and the head housing unit. [Figure 10] Cross-sectional view showing the connection relationship between the ejection element substrate and the head housing unit. [Figure 11] Enlarged cross-sectional view near the common flow path in the conventional example. [Figure 12] Enlarged cross-sectional view near the common flow path in the present embodiment. [Figure 13] Top view of the cover plate. [Figure 14] Schematic diagram showing the circulation of liquid near the ejection element substrate. [Figure 15] Schematic diagram showing the circulation of liquid near the ejection element substrate. [Figure 16] Top view and cross-sectional view of the bypass opening. [Figure 17] Top view of the cover plate in the second embodiment. [Figure 18] Enlarged cross-sectional view near the common flow path in the second embodiment.

Modes for Carrying Out the Invention

[0010] Embodiments of the present invention will be described below with reference to the drawings. Note that the following embodiments are not intended to limit the scope of the present invention, and not all combinations of features described in these embodiments are necessarily essential to the solution of the present invention. The same reference numerals are used for identical components.

[0011] The liquid ejection head and liquid ejection device of the present invention are applicable to industrial recording devices that are combined with various processing devices such as printers, copiers, facsimile machines with communication systems, and word processors with printer units. Furthermore, the liquid ejection head and liquid ejection device of the present invention can also be used for applications such as biochip fabrication, electronic circuit printing, and printing on non-absorbent media.

[0012] (First embodiment) The liquid ejection head according to this embodiment is an inkjet head that ejects ink, and the liquid ejection device is an inkjet recording device, but it is not limited to these as long as it ejects liquid.

[0013] <Liquid discharge device> Figure 1 is a schematic perspective view of a liquid ejection device 2000 to which the liquid ejection heads 1000 and 1001 in this embodiment can be applied. The liquid ejection device 2000 in this embodiment is a serial scan recording device that ejects liquid (hereinafter referred to as ink) from liquid ejection heads 1000 and 1001 that move in the X direction and records an image on a recording medium P that moves in the Y direction. The liquid ejection heads 1000 and 1001 can be mounted on a carriage 10, and the carriage 10 moves in the X direction (also referred to as the main scanning direction) along a guide axis 11. The recording medium P is transported by transport rollers (not shown) in a sub-scanning direction in the Y direction that intersects (orthogonal in this embodiment) the main scanning direction. That is, the carriage 10 moves relative to the recording medium P from which the liquid is ejected from the liquid ejection heads.

[0014] In this embodiment, a so-called serial-type liquid ejection head that ejects ink while moving in the main scanning direction is used as an example, but this is not limited to this. That is, an ejection port is formed along the width direction of the recording medium P, and an ejection head that can eject ink over the entire width direction of the recording medium P without moving in the main scanning direction may also be used. The carriage 10 is equipped with a liquid ejection head 1000 and a liquid ejection head 1001. The liquid ejection head 1000 is capable of ejecting three types of ink, and the liquid ejection head 1001 is capable of ejecting six types of ink. Each liquid ejection head is supplied with pressurized ink from nine ink tanks (21, 22, 23, 24, 25, 26, 27, 28, 29) via an ink supply tube 30. The ink supply unit 12 is equipped with a supply pump for pressurized supply, which will be described later.

[0015] As variations, the number of ink tanks can be reduced to seven by setting the three inks of the liquid ejection head 1000 to the same type of ink, or by adding more liquid ejection heads to create a liquid ejection device capable of ejecting 12 or more types of ink. In other words, the types of liquid ejected from the liquid ejection head 1000 and the liquid ejection head 1001 are not limited.

[0016] The liquid ejection head 1000 is fixedly supported on the carriage 10 by positioning means and electrical contacts of the carriage 10, and performs recording by ejecting ink while moving in the scanning direction, which is the X direction.

[0017] <Liquid dispensing head> Next, we will describe the liquid dispensing head. In this embodiment, the liquid dispensing head 1000 and the liquid dispensing head 1001 differ only in the type of liquid they dispense; therefore, the following explanation will use the liquid dispensing head 1000 as an example.

[0018] Figure 2 is a perspective view of the liquid discharge head 1000 in this embodiment, and Figure 3 is an exploded perspective view of the liquid discharge head 1000. The liquid discharge head 1000 comprises a discharge element unit 100, a circulation unit 200, a head housing unit 300, and a cover 502.

[0019] The discharge element unit 100 comprises a discharge element substrate 110 (also referred to as a discharge substrate) for discharging liquid, a support member 102 (also referred to as a support substrate) for supporting the discharge element substrate 110, an electrical wiring tape 103, and an electrical contact substrate 104. The discharge element substrate 110 has multiple rows of discharge ports, each consisting of multiple discharge ports 115 (Figure 8) arranged in the Y direction for discharging liquid. Furthermore, multiple rows of discharge ports are provided in the X direction.

[0020] The electrical contact board 104 has electrical contacts with the carriage 10 and supplies drive signals and energy to the circulation pump 203 mounted on the circulation unit 200 via the circulation unit connector 106 and pump wiring (not shown). The electrical contact board 104 also supplies drive signals and energy for ink ejection to the ejection element board 110 via the electrical wiring tape 103. Electrical connections are made by anisotropic conductive film (not shown), wire bonding, soldering, etc., but the connection method is not limited to these. In this embodiment, the connection between the ejection element board 110 and the electrical wiring tape 103 is made by wire bonding, and the electrical connection is sealed with a sealing material (shown) to protect it from corrosion by ink and external impacts.

[0021] The circulation unit 200 includes a first pressure adjustment mechanism 201, a second pressure adjustment mechanism 202 (Figure 4), and a circulation pump 203. Ink is supplied from the ink tank to the ink supply port 32 via an ink supply tube 30 and a head housing unit 300 having a tube connection part 31. In this embodiment, the circulation unit 200 is fixed to the head housing unit 300 with screws 501 to form an ink supply path. Elastic materials such as rubber or elastomer are used as sealing members at the connection parts in the ink supply path. The ejection element unit 100 is adhesively fixed to the head housing unit 300 and forms an ink supply path. The head housing unit 300 is constructed by combining parts that have been injection-molded from filler-filled resin in order to position it with respect to the carriage 10 and to form the shape of the ink flow path.

[0022] Figure 4 is a schematic diagram showing the steady-state circulation path for one color of ink applied to the liquid ejection device 2000 of this embodiment. Ink is supplied under pressure from the ink tank 21 to the liquid ejection head 1000 by the supply pump P0. The ink supplied from the ink tank 21 passes through a filter 204 provided inside the liquid ejection head 1000. At this time, foreign matter present in the ink is blocked by the filter 204, so the risk of foreign matter reaching the vicinity of the ejection port and causing ejection failure is reduced.

[0023] The ink that has passed through filter 204 is supplied to the first pressure adjustment mechanism 201. In Figure 4, the first pressure adjustment mechanism 201 is labeled "L" and the second pressure adjustment mechanism 202 is labeled "H". This indicates that "H" represents high negative pressure and "L" represents low negative pressure, which is the opposite of high and low relative to positive pressure. The first pressure adjustment mechanism 201 adjusts the pressure in the first pressure control chamber 211 to a predetermined pressure (negative pressure).

[0024] The circulation pump 203 is a piezoelectric diaphragm pump that changes the volume inside the pump chamber by inputting a drive voltage to a piezoelectric element attached to the diaphragm, causing two check valves to move alternately due to pressure fluctuations and thus pumping liquid. The second pressure control chamber 221 is pressure-regulated to a lower pressure than the first pressure control chamber 211 by the second pressure adjustment mechanism 202, and the circulation pump 203 pumps liquid from the second pressure control chamber 221, which is on the low-pressure (high negative pressure) side, to the first pressure control chamber 211, which is on the high-pressure (low negative pressure) side. In this embodiment, a piezoelectric element-driven diaphragm pump is adopted considering the size, weight, and ease of transmission of drive energy of the liquid discharge head. Other drive sources such as a motor or air operation (air supply and solenoid valve control) can also be used. The liquid pumping capacity of the circulation pump 203 will be described later.

[0025] While the circulation pump 203 is not limited to a diaphragm pump, it is preferable that it be a diaphragm pump because it is small enough to be mounted on the liquid discharge head 1000.

[0026] The discharge element substrate 110 has multiple pressure chambers 113 in which the pressure generated by the operation of the discharge element acts on the liquid discharged from multiple discharge ports. Multiple common supply channels 111 are connected to each pressure chamber 113, extending along the direction of the discharge port row and supplying liquid to the multiple pressure chambers 113. Furthermore, multiple common recovery channels 112 are connected to each pressure chamber 113, extending along the direction of the discharge port row and recovering liquid from the multiple pressure chambers 113.

[0027] The common supply channel 111 is connected to a distribution channel 301 for distributing liquid to multiple common supply channels 111. Furthermore, the multiple distribution channels 301 are connected to the first pressure control chamber 211 via a first bubble storage channel 310 for storing bubbles. In other words, the first bubble storage channel 310, the distribution channels 301, and the common supply channels 111 are pressure-regulated to the high-pressure (upstream) side.

[0028] The common recovery channel 112 is connected to a consolidation channel 302 for collecting liquid from multiple common recovery channels 112. Furthermore, the multiple consolidation channels 302 are connected to the second pressure control chamber 221 via a second bubble storage channel 320 for storing bubbles. In other words, the second bubble storage channel 320, the consolidation channels 302, and the common recovery channels 112 are pressure-regulated to the low-pressure (downstream) side.

[0029] In this way, by adjusting the pressure between the upstream (high pressure) side and the downstream (low pressure) side, a pressure difference is created between the common supply channel 111 and the common recovery channel 112, and ink flow occurs in each pressure chamber 113 in the direction of arrow α in Figure 4. Due to this ink flow caused by the pressure difference, locally thickened ink near the discharge port and pressure chamber that is not being discharged during standby and recording is recovered from the pressure chamber 113, thus suppressing discharge failures. In other words, discharge failures are suppressed by the circulation of liquid in the order of distribution channel, common supply channel, pressure chamber, common recovery channel, and aggregation channel by the circulation pump 203.

[0030] Figure 5 is a side view of the liquid ejection head 1000, Figure 6(a) shows a cross-sectional view AA of Figure 5, and Figure 6(b) shows a cross-sectional view BB of Figure 5. The ejection element substrate 110 has rows of ejection ports arranged along the direction of movement Y of the recording medium P, and ink is ejected from the ejection ports in the direction of gravity G.

[0031] As shown in Figures 6(a) and 6(b), the distribution channel 301 and the aggregation channel 302 are formed by a support member 102 that supports the discharge element substrate 110. Also, as shown in Figures 6(a) and 6(b), the first bubble storage channel 310 and the second bubble storage channel 320 are formed in the head housing unit 300.

[0032] The support member 102 and the discharge element substrate 110 are connected via a cover plate 151 (also referred to as a plate-shaped member) (Figure 8). The cover plate 151 has a supply opening 121 and a recovery opening 122. The cover plate 151 is interposed between the discharge element substrate 110 and the support member 102 and forms part of the wall surface of multiple common supply channels 111 and multiple common recovery channels 112. The liquid in the distribution channel 301 is distributed to the common supply channel 111 via the supply opening 121. The liquid in the common recovery channel 112 is collected in the aggregation channel 302 via the recovery opening 122.

[0033] Next, the details of the first pressure adjustment mechanism 201 and the second pressure adjustment mechanism 202 will be described. Figure 7 is an enlarged cross-sectional view of the vicinity of the first pressure adjustment mechanism 201 and the second pressure adjustment mechanism 202. As described above, the liquid in the ink supply unit 12 is supplied to the circulation unit 200 via the ink supply tube 30. Then, ink is supplied to the first pressure adjustment mechanism 201 from the ink supply port 32 provided inside the circulation unit 200 via the filter 204.

[0034] The first pressure adjustment mechanism 201 consists of a valve 232, a valve spring 233, a flexible member 231, a pressure plate 235, and a pressure adjustment spring 234. When the volume of the first pressure control chamber 211 decreases due to ink discharge or the like, the pressure plate 235 deforms the flexible member 231 and the pressure adjustment spring to maintain a constant pressure. The compression deformation of the pressure adjustment spring 234 deforms the valve spring 233 in a direction that compresses it via the valve 232, thereby supplying ink to the first pressure control chamber 211. This behavior makes it possible to maintain a constant ink supply and pressure. The negative pressure in the first pressure control chamber 211 is set by the contact position of the pressure adjustment spring 234 and the pressure plate 235 of the valve 232.

[0035] The second pressure adjustment mechanism 202 has the same configuration as the first pressure adjustment mechanism 201, and consists of a valve 242, a valve spring 243, a flexible member 241, a pressure plate 245, and a pressure adjustment spring 244. In the second pressure adjustment mechanism 202, the only difference is that the ink supply source is the first pressure control chamber 211, and the pressure adjustment principle is the same as that of the first pressure adjustment mechanism 201.

[0036] The circulation pump 203 is connected to transfer ink from the second pressure control chamber 221 to the first pressure control chamber 211. In this embodiment, the circulation pump 203 employs a small diaphragm pump using a piezoelectric element. Since the pump can be driven by applying a voltage pulse to the piezoelectric element, the circulation pump 203 can be controlled ON / OFF by the voltage pulse output from the main unit. When the circulation pump 203 transfers ink from the second pressure control chamber 221 to the first pressure control chamber 211, the first pressure control chamber 211 becomes pressurized by the amount of liquid transferred, and similarly, the second pressure control chamber 221 becomes negatively pressurized by the amount of liquid transferred. The second pressure control chamber 221 recovers ink through the pressure adjustment mechanism 202, but since the pressure adjustment mechanism 202 recovers ink from both the first pressure control chamber 211 and the pressure chamber 113, a circulating flow is created while maintaining a constant pressure. The circulating flow generated through this pressure chamber 113 makes it possible to remove thickened ink caused by evaporation near the nozzle, enabling stable dispensing.

[0037] (Detailed description of the ejection element substrate) Figure 8 is a perspective view showing cross-sections of the discharge element substrate 110 and the cover plate 151. In Figure 8, four rows of discharge ports are formed on the discharge port forming member 152 of the discharge element substrate 110, but the number of discharge port rows is not limited to this.

[0038] The ejection element substrate 110 comprises an ejection port forming member 152 and a substrate 150. The substrate 150 is preferably made of silicon, but is not limited to silicon. It is preferable that a heat-retaining heater (illustrated) is provided on the substrate 150 to stabilize ink ejection from the ejection port 115. Furthermore, in order to equalize the temperature of the entire ejection element substrate and ensure stable bonding with the substrate 150, it is preferable to use alumina as the support member 102, which has a coefficient of linear expansion equivalent to silicon and high thermal conductivity. On the other hand, from the viewpoint of reducing the number of locations where bubbles are generated due to temperature rise, the support member 102 may be made of an insulating material such as resin. Similarly, the cover plate 151 may be made of an insulating material such as resin.

[0039] Here, the flow of liquid within the discharge element substrate 110 will be described. The cover plate 151 functions as a lid that forms part of the wall of the common supply channel 111 and the common recovery channel 112 formed in the substrate 150 of the discharge element substrate 110. The discharge element substrate 110 is formed by laminating the substrate 150 and the discharge port forming member 152 made of a photosensitive resin, and the cover plate 151 is bonded to the back surface of the substrate 150. A discharge element 154 is formed on one side of the substrate 150, and grooves constituting the common supply channel 111 and the common recovery channel 112 extending along the row of discharge ports are formed on the back side thereof.

[0040] The discharge element 154 may be a thermoelectric element that converts given electrical energy into thermal energy to generate pressure, or a piezoelectric element that converts given electrical energy into mechanical energy to generate pressure. Furthermore, it is not particularly limited as long as it can generate energy for discharging liquid.

[0041] Figure 9 is a perspective view showing the flow path at the connection between the head housing unit 300 and the support member 102, relative to a structural cross-sectional perspective view of the discharge element substrate 110. Figure 10(a) is a structural cross-sectional view of the EE section in Figure 9, and Figure 10(b) is a structural cross-sectional view of the FF section in Figure 9.

[0042] The common supply channel 111, formed by the substrate 150 and the cover plate 151, is connected to the first pressure control chamber 211 via the distribution channel 301 and the first bubble storage channel 310. The common recovery channel 112, also formed by the substrate 150 and the cover plate 151, is connected to the second pressure control chamber 221 via the aggregation channel 302 and the second bubble storage channel 320. This creates a pressure difference between the common supply channel 111 and the common recovery channel 112. This pressure difference causes the liquid in the common supply channel 111 within the substrate 150 to flow through the individual supply channel 116, pressure chamber 113, and individual recovery channel 117 to the common recovery channel 112 (arrow C in Figure 8). This ink circulation allows for the recovery of thickened ink and bubbles generated by evaporation from the discharge port 115, as well as bubbles, from the discharge port 111 to the common recovery channel 112, even in the discharge port 115 and pressure chamber 113 where the discharge operation is not in progress. Furthermore, the risk of the ink in the discharge port 115 or pressure chamber 113 becoming thicker, or the concentration of the colorant in the ink increasing, can be reduced. The liquid recovered into the common recovery channel 112 is further recovered from the recovery opening 122 through the aggregation channel 302 to the second bubble storage channel 320.

[0043] In this embodiment, the liquid discharge head has a bypass opening 123 formed in the cover plate 151 that connects the common supply channel 111 and the consolidation channel 302 without going through the pressure chamber 113. Therefore, bubbles mixed into the common supply channel 111 and generated bubbles 500 can be recovered from the common supply channel 111 to the consolidation channel 302 by the differential pressure between the common supply channel 111 and the consolidation channel 302 (arrow D in Figure 8). The bubbles 500 recovered in the consolidation channel 302 flow to the second bubble storage channel 320 and are temporarily stored there.

[0044] In Figures 10(a) and 10(b), the arrows (solid lines) shown within the flow path indicate the flow of circulating ink driven by the circulation pump 203 when not recording (not discharging). In Figure 10(a), ink flows from the first pressure control chamber 211 to the common supply flow path 111 via the head housing unit 300, distribution flow path 301, and supply opening 121 that constitute the first bubble storage flow path 310. From the common supply flow path 111, the ink flows through the pressure chamber 113 where the ink is discharged, to the common recovery flow path 112, and is recovered to the second bubble storage flow path 320 via the recovery opening 122 and aggregation flow path 302. Furthermore, the liquid that has flowed into the second bubble storage flow path 320 flows to the second pressure control chamber 221. The circulation pump 203 delivers ink from the second pressure control chamber 221 to the first pressure control chamber 211. In this way, the ink circulation flow completes one full rotation.

[0045] As described above, since the ink circulation according to this embodiment is completed within the flow path of the liquid ejection head 1000, an ink recovery tube for recovering ink from the liquid ejection head 1000 to the liquid ejection device is not required.

[0046] Furthermore, bubbles 500 generated within the flow path of the liquid ejection head 1000 will be present in one of the circulation flows. Bubbles 500 are generated during ink filling of the liquid ejection head, foaming due to ink flow, supersaturation of dissolved gases in the ink due to temperature rise or pressure reduction in the flow path. If bubbles 500 are drawn into the pressure chamber 113, it can cause ink ejection failure and lead to ejection problems. Therefore, it is necessary to store bubbles 500 in the circulation flow path far from the pressure chamber 113 to prevent them from flowing into the pressure chamber 113.

[0047] Figure 11 is an enlarged cross-sectional view of the common flow path of a liquid ejection head in a conventional example. Figure 11(a) shows an enlarged cross-sectional view of the vicinity of the common supply flow path 111. Figure 11(b) shows an enlarged cross-sectional view of the vicinity of the common recovery flow path 112. In liquid ejection heads, control measures such as using a heat-retaining heater to equalize the temperature of the ejection element substrate 110 are sometimes implemented to improve print quality by stabilizing the ink ejection amount. Also, in the case of an ejection method that uses a heating element as the ejection element, as in the liquid ejection head according to this embodiment, the ejection element substrate 110 heats up. In these cases, the ink circulating in the common supply flow path 111 also heats up due to the heat-retaining heater or heating element, so the amount of saturated dissolved gas decreases locally, and the dissolved gas is generated as bubbles. The bubbles 500 generated by the heating gather near the confluence of the liquid flowing from multiple supply openings 121 into the common supply flow path 111, and buoyancy (in the -Z direction in Figure 11(a)) and circulating flow (in the Z direction in Figure 11(a)) act on these bubbles. In this case, if the buoyancy is greater than the circulating flow, the bubbles 500 will not be drawn into the pressure chamber 113 but will remain stagnant near the ceiling of the confluence. Since there is no opening in this area for the bubbles 500 to escape, there is a risk that the bubbles 500 will continue to accumulate without being discharged. Furthermore, if the circulating flow becomes greater than the buoyancy, there is a concern that the bubbles stagnant near the ceiling may be drawn into the pressure chamber or block the flow path, causing discharge problems.

[0048] On the other hand, as shown in Figure 11(b), since the buoyancy (-Z direction) and circulation flow (-Z direction) acting on the bubbles 500 generated in the common recovery channel 112 are the same, the bubbles in the common recovery channel 112 are collected in the collection channel 302 from the recovery opening 122.

[0049] As described above, in conventional liquid discharge heads, bubbles 500 tend to accumulate in the common supply channel 111, which is near the pressure chamber 113, and these bubbles may be drawn into the pressure chamber 113, potentially causing discharge problems.

[0050] Next, Figure 12 shows an enlarged cross-sectional view of the common flow path of the liquid discharge head in this embodiment. Figure 12(a) shows an enlarged cross-sectional view of the vicinity of the common supply flow path 111. Figure 12(b) shows an enlarged cross-sectional view of the vicinity of the common recovery flow path 112. In the liquid discharge head according to this embodiment, a bypass opening 123 is formed that connects the common supply flow path 111 and the aggregation flow path 302 without going through the pressure chamber 113. The location where the bypass opening 123 is formed is near the confluence of liquids flowing from multiple supply openings 121, and is the ceiling of the common supply flow path 111 where air bubbles tend to accumulate. In other words, the bypass opening 123 is formed in a plate-shaped member (cover plate 151). Because the bypass opening 123 is formed in a position where air bubbles tend to stagnate in the common supply flow path 111, air bubbles in the common supply flow path 111 are recovered into the aggregation flow path 302 via the bypass opening 123 (direction of arrow D in Figure 12(a)).

[0051] The bubbles 500 collected in the consolidation channel 302 flow to the second bubble storage channel 320 due to buoyancy and circulation. As shown in Figures 6(a) and 6(b), the second bubble storage channel 320 has a narrower channel width on the side connected to the consolidation channel 302 in order to collect liquid from the consolidation channel 302, but a wider channel width on the side connected to the second pressure control chamber 221. In other words, the second bubble storage channel 320 has a first section 322 and a second section 323 located vertically above the first section when the liquid discharge head is in use, with the channel width of the second section being wider than that of the first section. This allows many bubbles to be retained in the second section 323 after the liquid is collected from the consolidation channel 302 where the channels are densely packed. Note that the channel width referred to here is the channel width in a predetermined direction (Y direction). Furthermore, the usage status of the liquid ejection head refers to the position in which ink is ejected from the liquid ejection head to record images, characters, etc., onto the recording medium.

[0052] If bubbles enter the second pressure control chamber 221 from the second bubble storage channel 320, the second pressure control chamber 221 will open and close its valve due to the internal pressure, which may cause the second pressure adjustment mechanism to malfunction. Therefore, the second bubble storage channel 320 has multiple bends 321, as shown in Figure 6. The presence of the bends 321 makes it easier to retain bubbles near the bends 321, thereby suppressing the entry of bubbles into the second pressure control chamber 221.

[0053] On the other hand, as shown in Figure 12(b), the bubbles 500 generated in the common recovery channel 112 are collected in the collection channel 302 from the recovery opening 122, similar to the conventional example. Since a circulating flow is generated in the liquid discharge head by the circulation pump 203, even if a bypass opening 123 is formed, it is unlikely that liquid will flow from the collection channel 302 to the bypass opening 123.

[0054] As described above, the liquid discharge head according to this embodiment has a bypass opening 123, which reduces the risk of bubbles accumulating in the common supply channel 111, which is near the pressure chamber 113. In other words, since the risk of bubbles accumulating in the channel near the pressure chamber 113 can be reduced without increasing the size of the liquid discharge head and liquid discharge device, discharge defects can be suppressed. Furthermore, since bubbles that tend to accumulate in the common supply channel 111, which is near the pressure chamber 113, can be kept away from the discharge element substrate 110, continuous printing for long periods of time becomes possible. Therefore, the liquid discharge head according to this embodiment is suitable for large-format printing such as large-format posters.

[0055] A mechanism may be provided to discharge the bubbles stored in the second bubble storage channel 320 to the outside of the liquid discharge head. For example, a mechanism may be provided in which a part of the wall surface of the circulation channel is formed with a film that allows gas to pass through but not liquid, and the bubbles are discharged by reducing the pressure at the end of the film.

[0056] Another possible location for providing a bypass opening is to form an opening in the ejection element substrate 110 at a position that does not pass through the pressure chamber, thereby providing a bypass. When such a bypass is provided, it becomes possible to circulate a large amount of ink within the ejection element substrate without increasing the differential pressure between the upstream and downstream flow paths of the pressure chamber. However, when such a bypass opening is provided, the increased flow rate of the circulating flow path can cause pressure loss, leading to pressure variations between different pressure chambers and potentially causing ejection failures. In particular, when a bypass opening and bypass flow path are provided at the end of a relatively fine flow path, an increase in the flow rate through the flow path also increases the flow resistance, making it more likely for pressure variations and ejection failures to occur.

[0057] On the other hand, as in the liquid discharge head of this embodiment, if the common supply channel 111 and the aggregate channel 302 are connected by a bypass opening 123 that does not go through the pressure chamber 113, it becomes possible to shorten the length of the bypass channel. Therefore, it is possible to reduce the size of the discharge element substrate 110 while suppressing pressure fluctuations.

[0058] Furthermore, a wider common supply channel 111 and common recovery channel 112 are advantageous in terms of reducing pressure variation because a wider channel width reduces flow resistance. However, increasing the channel width of the common supply channel 111 and common recovery channel 112 increases the size of the discharge element substrate 110, which is disadvantageous from a cost standpoint. In the liquid discharge head according to this embodiment, even if a bypass opening 123 is provided, it is possible to make the channel width of the common supply channel 111 and common recovery channel 112 narrow to 250 μm or less. Here, the channel width of the common supply channel 111 refers to the length of the common supply channel in the direction of arrangement of the row of common supply channels, which is made up of multiple common supply channels arranged in a sequence. The channel width of the common recovery channel 112 refers to the length of the common recovery channel in the direction of arrangement of the row of common recovery channels, which is made up of multiple common recovery channels arranged in a sequence.

[0059] Next, the location where the bypass opening 123 is formed will be described in detail. Figure 13 is a top view of the cover plate 151. Figure 13 shows the cover plate 151 corresponding to the ejection element substrate 110, which has four rows of ejection ports and is capable of ejecting three types of ink. Figures 14 and 15 are schematic diagrams showing the ink flow near the bypass opening 123. Figures 14 and 15 are schematic diagrams showing one of the rows of ejection ports and the flow path (the part where ink is present) connected to it. In Figures 14 and 15, the arrows represent the ink flow.

[0060] As shown in Figure 13, there are five supply openings 121 corresponding to one row of discharge ports, and they are formed in positions that include both ends of the common supply channel 111 to which they are connected. In addition, there are four recovery openings 122 corresponding to one row of discharge ports, and the recovery openings 122 are not formed at both ends of the common recovery channel 112.

[0061] Since the common supply channel 111 and the common recovery channel 112 are narrow in width of 250 μm or less, the ink flow from the common supply channel to the pressure chamber 113 (arrow C) shown in Figure 14 can suppress pressure variations due to pressure loss as the distance the ink flows within the discharge element substrate is shorter. For this reason, it is preferable to arrange the supply opening 121 and the recovery opening 122 at approximately equal intervals, as shown in Figure 13.

[0062] Figure 15 shows the ink flow (arrow C) recovered from the pressure chamber 113 into the common recovery channel 112. The ink recovered in the common recovery channel 112 flows toward the recovery opening 122 (solid arrow in Figure 15). Then, it is recovered into the aggregation channel 302 via the recovery opening 122. The ink flow from the common supply channel 111 through the pressure chamber 113 (arrows C and solid arrow) flows in the direction that minimizes the channel length including the common recovery channel 112. Therefore, the ink flow confluence point P within the common supply channel 111 is near the recovery opening 122. The ink flow (dotted arrow D) from the supply opening 121 in Figure 14, passing through the common supply channel 111 and recovered into the aggregation channel 302 via the bypass opening 123, discharges air bubbles within the common supply channel 111 without passing through the pressure chamber 113. As described above, from the viewpoint of efficiently discharging bubbles in the common supply channel 111 into the converging channel 302, it is preferable to provide a bypass opening near the ink flow confluence point P in the common supply channel 111. Furthermore, since it is necessary to discharge bubbles into the converging channel 302 before they are drawn into the pressure chamber 113, it is preferable to provide a bypass opening 123 in a position that is opposite to the flow to the pressure chamber 113 (arrow C) and where bubbles can be efficiently discharged by buoyancy. In other words, it is preferable to place the bypass opening 123 on the cover plate 151.

[0063] Furthermore, in the direction of arrangement of a row of recovery openings, which consists of multiple recovery openings 122 arranged in a sequence, the bypass opening 123 is formed between the multiple recovery openings 122. This allows the bypass opening 123 to be provided at a position corresponding to the common supply channel 111 in a row of common channel sections, which consists of common supply channels 111 and common recovery channels 112 arranged alternately.

[0064] Furthermore, in the direction of the arrangement of the supply opening row, which is made up of multiple supply openings 121, the bypass opening 123 is formed between the multiple supply openings 121. This allows the bypass opening 123 to be provided at the point where the liquids flowing from the multiple supply openings 121 into the common supply channel 111 converge, making it easier to collect the bubbles 500 into the aggregation channel 302.

[0065] Furthermore, as shown in Figures 14 and 15, it is preferable that the distribution channels 301 and the consolidation channels 302 are alternately aligned in the direction of the arrangement of the discharge port rows. Moreover, it is preferable that the directions of the protruding shapes of the distribution channels 301 and the consolidation channels 302 are staggered. This makes it possible to provide many distribution channels 301 and consolidation channels 302 in a narrow area of ​​the support member 102.

[0066] Next, the shape of the bypass opening 123 will be described. Figure 16 shows a top view of the bypass opening and a cross-sectional view of the bypass opening when it is cut diagonally. The bypass opening 123 in this embodiment is circular in shape with an opening diameter of about 0.1 mm, as shown in Figure 16(a). The thickness of the bypass opening 123 is equal to the thickness of the cover plate 151, which is about 0.3 mm.

[0067] The larger the diameter of the bypass opening 123, the greater the flow rate in the common supply channel 111, which in turn increases the pressure variation in each pressure chamber 113. Furthermore, a larger diameter of the bypass opening 123 increases the fluid delivery capacity required of the circulation pump 203 to maintain the differential pressure between the upstream and downstream channels of the pressure chamber 113. For these reasons, it is preferable that the bypass opening 123 be as narrow as possible while still allowing air bubbles to pass through.

[0068] As shown in Figure 16(a), the opening shape of the bypass opening in this embodiment is circular. When the opening shape of the bypass opening 123 is circular (or at least elliptical), the bubbles 500 are trapped so as to close the bypass opening 123, so that the circulating flow covers the entire bubble and the bubble 500 can pass through the bypass opening 123 while deforming. Such a bypass opening 123 can be formed by dry etching the silicon substrate.

[0069] Figures 16(b) and 16(c) show modified examples of bypass openings. The bypass opening in Figure 16(b) is rectangular, and the bypass opening in Figure 16(c) is parallelogram-shaped. When the diameter of the bypass opening 123 decreases, for bubbles larger than the opening diameter, a reaction force is generated that resists the dynamic pressure of the ink flow due to the surface tension of the bubbles and the buoyancy of the bubbles. When the opening shape of the bypass opening is rectangular or parallelogram-shaped, bubbles are trapped without blocking the bypass opening, allowing the bubbles to pass through the bypass opening while deforming due to the dynamic pressure of the ink flow caused by the circulating differential pressure and buoyancy. Bypass openings of these shapes can be formed by applying photolithography to a material such as silicone or photosensitive resin.

[0070] If the diameter of the bypass opening 123 is larger than that of the recovery opening 122, the amount of liquid flowing from the common supply channel 111 to the concentrated channel 302 via the bypass opening 123 will be greater than the amount of liquid flowing from the common supply channel 111 to the concentrated channel 302 via the pressure chamber 113. Therefore, it is preferable that the diameter of the bypass opening 123 be smaller than that of the recovery opening 122.

[0071] If the diameter of the bypass opening 123 is larger than that of the supply opening 121, more liquid will be recovered from the common supply channel 111 to the aggregation channel 302 via the bypass opening 123 than the amount of liquid supplied from the distribution channel 301 to the common supply channel 111. Therefore, it is preferable that the diameter of the bypass opening 123 be smaller than that of the supply opening 121.

[0072] <Fluid delivery capacity of the circulation pump considering the bypass opening> As shown in FIG. 8, it is possible to remove the thickened ink due to ink evaporation near the discharge port by means of the circulation flow through the pressure chamber 113. At this time, the required circulation ink flow rate C is determined by the viscosity of the ink, the shape of the pressure chamber 113 and the discharge port 115, etc. The control factor for determining this flow rate C is the pressure difference between the individual supply flow path 116 and the individual recovery flow path 117, and it is necessary to keep it constant by the first pressure adjustment mechanism 201 and the second pressure adjustment mechanism 202. Also, due to this pressure difference, a flow (arrow D in FIG. 8) also occurs in the bypass opening 123, and the flow rate D is determined. In order for the first pressure adjustment mechanism 201 and the second pressure adjustment mechanism 202 to function properly, it is necessary to supply a flow rate larger than the flow rate per unit time flowing into the distribution flow path 301 by the circulation pump 203.

[0073] In this embodiment, the flow rate C of each pressure chamber 113 flowing per unit time is set to 1.5e ALL ,

[0074] , , mL / min, and the pressure chambers 113 are arranged in a range of 1.5 inches at intervals of 4 columns and 600 dpi in the discharge port row. At this time, the total C of the ink flow rate C per color ALL is C ALL = 4 × 600 × 1.5 × 1.5e -4 = 0.54 mL / min. In this embodiment, the pressure difference at which the flow rate C of each pressure chamber 113 becomes 1.5e -4 mL / min is 70 [mmAq] when the ink viscosity is adjusted to 5 cps (7 cP at room temperature of 25 °C) by adjusting the temperature of the discharge element substrate 110. And substantially the same pressure difference is also applied to the bypass opening 123. In this embodiment, the bypass openings 123 are arranged at four locations with respect to the four discharge port rows, and have a straight tube shape with an opening diameter φ = 0.1 mm and a length of 0.3 mm. The flow rate is determined by the cross-sectional area and length of the flow path and the differential pressure. The flow rate per unit time of the ink flow (dotted arrow D) in the bypass opening 123 is Q = 5.6e -2 mL / min, and the total of the flow rate D is Q ALL = 4 × 4 × 5.6e -2 = 0.896 mL / min.

[0074] In this embodiment, the ink supply capacity per unit time of the circulation pump 203 is C ALL + QALL The required flow rate is 1.436 mL / min or higher, but it is set to 2.1 mL / min. When the flow path lengths of the common supply channel 111 and the common recovery channel 112 are long, pressure loss occurs due to the ink flow. To compensate for this, the required differential pressure must be increased, and the pressure difference must be set higher than 70 [mmAq]. Furthermore, the required supply capacity of the circulation pump 203 for maintaining the differential pressure must also be set higher to match the above pressure setting.

[0075] Furthermore, when the ink viscosity is low (4 cps or less at 25°C) and the pressure loss in the circulation path is small, or when the number of discharge ports and bypass openings is large, the liquid delivery capacity of the circulation pump 203 (the flow rate that can be delivered per unit time) needs to be set high. Also, when a large amount of nozzle circulation flow rate is required due to the use of highly volatile ink or temperature control settings, the liquid delivery capacity of the circulation pump 203 needs to be set high.

[0076] On the other hand, if the ink viscosity is high (10 cps or more at 25°C) and the temperature control setting is low, or if there is no temperature control mechanism, the ink supply capacity of the circulation pump 203 can be set low, but the circulation pump 203 needs to be suitable for high-viscosity inks.

[0077] For example, regarding ink viscosity, inks with a viscosity of 0.89 cps to 30 cps at 25°C are sometimes used in inkjet recording devices. In this case, the circulation pump 203 is required to have a configuration that can deliver such ink. A circulation pump 203 that satisfies these requirements (per ink color) has a pump chamber volume of 100 cm³. 3 An air-operated diaphragm pump with a maximum flow rate of 2000 mL / min or less can be used. Such a circulation pump can accommodate inks within the expected viscosity range and is compatible with serial scanning inkjet recording heads.

[0078] To use the liquid discharge head as a serial scan type, the size and weight of the circulation pump 203 must be considered. Therefore, the amount of pure water that the circulation pump 203 can deliver per unit time at 25°C must be within the volume of the pump chamber (1 cm³). 3 It is preferable that the flow rate is 25 mL / min or less. If a circulation pump with higher efficiency is used, the volume of the circulation pump 203 occupying the liquid discharge head will be 100 cm³. 3 This is because it exceeds a certain limit, which reduces the effectiveness of the serial scan method.

[0079] On the other hand, in a diaphragm pump, check valves are provided at the inlet where ink flows into the pump chamber and at the outlet where ink is discharged from the pump chamber, so it is necessary for these check valves to be opened and closed stably. Therefore, the amount of pure water that the circulation pump 203 can deliver per unit time at 25°C is limited by the volume of the pump chamber (1 cm³). 3 It is preferable that the flow rate is 0.003 mL / min or more per unit. When the fluid delivery capacity of the circulation pump 203 satisfies the above conditions, it becomes possible to stably open and close the check valve.

[0080] Based on the above constraints, the circulation pump according to this embodiment employs a diaphragm pump capable of delivering approximately 0.7 mL / min of pure water at 25°C per unit time. By ensuring that the liquid delivery capacity of the circulation pump is greater than or equal to the minimum required liquid delivery capacity and less than or equal to the maximum liquid delivery capacity, the pump mechanism size can be reduced to 3 cm without compromising the liquid delivery characteristics. 3 The pressure is kept to a minimum. In other words, even if the circulation pump 203 is mounted on the liquid ejection head, the circulation pump 203 can be miniaturized, and the liquid ejection head according to this embodiment is highly suitable for the serial scan method. Furthermore, in the liquid ejection head according to this embodiment, even if more ink than necessary is supplied to the first pressure control chamber 211, the second pressure adjustment mechanism 202 returns the excess amount of ink to the second pressure control chamber 221, so there is little risk of problems occurring.

[0081] (modified version) Next, the configuration of the liquid discharge head in the modified example will be described. In the modified example, the positions of the supply opening 121, the recovery opening 122, and the bypass opening 123 formed in the cover plate 151 differ from those of the first embodiment. In the following description, only the parts that differ from the first embodiment will be described, and the parts that are the same as in the first embodiment will not be described.

[0082] Figure 17 shows a top view of the cover plate 151 in a modified example. In the first embodiment, supply openings 121 were provided on both ends of the cover plate 151, but in the modified example, the cover plate 151 differs in that recovery openings 122 are provided on both ends of the cover plate 151. In other words, the supply openings 121 are not provided in a position that includes both ends of the common supply channel 111, and the recovery openings 122 are provided in a position that includes both ends of the common recovery channel 112. In other words, the positions of the supply openings 121 and recovery openings 122 are swapped between the first embodiment and the modified example. Also, four supply openings 121 are formed corresponding to one row of discharge ports, and five recovery openings 122 are formed.

[0083] Figure 18 shows an enlarged cross-sectional view of the common flow path of the liquid discharge head. Figure 18(a) shows an enlarged cross-sectional view of the vicinity of the common supply flow path, and Figure 18(b) shows an enlarged cross-sectional view of the vicinity of the common recovery flow path. Compared with the first embodiment, in the modified liquid discharge head, the positions of the supply opening 121 and the recovery opening 122 are swapped. Accordingly, the positions of the distribution flow path 301 and the aggregation flow path 302 are also swapped. As shown in Figure 18(a), in the modified embodiment, a bypass opening 123 is formed at the end of the common recovery flow path 112. Therefore, unlike the first embodiment, the risk of bubbles accumulating at the end of the common supply flow path is suppressed, and all bubbles in the common supply flow path 111 are more easily recovered into the aggregation flow path 302 via the bypass opening 123. In other words, the risk of bubbles accumulating at the end of the common supply flow path 111 being drawn into the pressure chamber 113 is also reduced, thus suppressing discharge failures.

[0084] To summarize, this disclosure includes the following components:

[0085] (Composition 1) Multiple rows of outlets arranged in a manner for dispensing liquid, Multiple pressure chambers through which pressure acts on the liquid discharged from the multiple outlets, A plurality of common supply channels extend along the direction of arrangement of the discharge port rows and supply liquid to the plurality of pressure chambers, A plurality of common recovery channels extend along the direction of arrangement of the discharge port rows and recover liquid from the plurality of pressure chambers, A distribution channel for distributing liquid to the aforementioned multiple common supply channels, A collection channel for collecting liquid from the aforementioned multiple common collection channels, A liquid dispensing head having, A circulation pump that circulates the liquid in the order of the distribution channel, the common supply channel, the pressure chamber, the common recovery channel, and the aggregation channel, A bypass opening connects the common supply channel and the aggregate channel without going through the pressure chamber, A liquid dispensing head characterized by having the following features.

[0086] (Configuration 2) The collection opening row comprises a plurality of collection openings arranged to connect the common collection channel and the aggregation channel, The liquid discharge head according to configuration 1, wherein the bypass opening is formed between the plurality of recovery openings in the direction of arrangement of the row of recovery openings.

[0087] (Composition 3) The common supply channel and the aggregated channel are connected by a row of supply openings arranged in a line, A liquid dispensing head according to configuration 1 or 2, wherein the bypass opening is formed between the plurality of supply openings in the direction of arrangement of the supply opening row.

[0088] (Composition 4) The liquid discharge head according to any one of configurations 1 to 3, wherein the opening shape of the bypass opening is elliptical.

[0089] (Composition 5) Having a common supply channel array formed by arranging the plurality of common supply channels, A liquid discharge head according to any one of configurations 1 to 4, wherein the length of the common supply channel in the direction of arrangement of the common supply channel row is 250 μm or less.

[0090] (Composition 6) Having a common recovery channel array in which the plurality of common recovery channels are arranged, A liquid discharge head according to any one of configurations 1 to 5, wherein the length of the common recovery channel in the direction of arrangement of the common recovery channel row is 250 μm or less.

[0091] (Composition 7) A liquid discharge head according to any one of configurations 1 to 6, wherein the amount of pure water that the circulation pump can deliver per unit time at 25°C is 2000 mL / min or less.

[0092] (Composition 8) The aforementioned circulation pump has a pump chamber that functions as a pump, The amount of pure water that the circulation pump can deliver per unit time at 25°C is equal to the volume of the pump chamber (1 cm³). 3 A liquid dispensing head according to any one of items 1 to 7, with a dispensing rate of 25 mL / min or less per unit.

[0093] (Composition 9) The aforementioned circulation pump has a pump chamber that functions as a pump, The amount of pure water that the circulation pump can deliver per unit time at 25°C is the volume of the pump chamber (1 cm³). 3 A liquid dispensing head according to any one of items 1 to 8, having a flow rate of 0.003 mL / min or more per unit.

[0094] (Composition 10) A liquid dispensing head according to any one of configurations 1 to 9, wherein the viscosity of the liquid discharged from the discharge port at 25°C is 0.89 cps or more and 30 cps or less.

[0095] (Composition 11) The distribution channel and the aggregation channel each have a plurality of, A liquid discharge head according to any one of configurations 1 to 10, wherein the distribution channel and the aggregation channel are alternately aligned in the direction of the arrangement of the discharge port rows.

[0096] (Composition 12) A discharge substrate having the plurality of discharge port rows, the plurality of pressure chambers, the plurality of common supply channels, and the plurality of common recovery channels formed therein, A support substrate that supports the discharge substrate, A plate-shaped member interposed between the discharge substrate and the support substrate, which becomes part of the wall surface of the plurality of common supply channels and the plurality of common recovery channels, It has, The support substrate has the distribution channel and the aggregation channel formed therein. The liquid discharge head according to any one of configurations 1 to 11, wherein the plate-shaped member has the bypass opening formed therein.

[0097] (Composition 13) The liquid discharge head according to configuration 12, wherein the plate-shaped member has a recovery opening that connects the aggregation channel and the common recovery channel, and the opening diameter of the bypass opening is smaller than the opening diameter of the recovery opening.

[0098] (Composition 14) The liquid discharge head according to configuration 12, wherein the plate-shaped member has a supply opening that connects the distribution channel and the common supply channel, and the opening diameter of the bypass opening is smaller than the opening diameter of the supply opening.

[0099] (Composition 15) Having multiple of the aforementioned aggregation channels, The system includes a bubble storage channel connected to the aforementioned plurality of aggregation channels, The liquid discharge head according to any one of configurations 1 to 14, wherein the bubble storage channel is provided with a bent portion for storing bubbles.

[0100] (Composition 16) The aforementioned bubble storage channel is provided with a first section and a second section. In the operating state of the liquid dispensing head, the second portion is located vertically above the first portion. The liquid dispensing head according to configuration 15, wherein in a predetermined direction, the length of the second portion is longer than the length of the first portion.

[0101] (Composition 17) A liquid dispensing head as described in any one of items 1 to 16, A carriage for mounting the aforementioned liquid dispensing head, A liquid dispensing device having, The liquid dispensing device is characterized in that the carriage moves relative to the recording medium from which the liquid is dispensed from the liquid dispensing head. [Explanation of symbols]

[0102] 111 Common supply channel 112 Common recovery channel 113 Pressure Chamber 115 Discharge port 123 Bypass opening 203 Circulation pump 301 Distribution channel 302 Concentrated channel 1000 liquid dispensing heads

Claims

1. Multiple rows of outlets arranged in a manner for dispensing liquid, Multiple pressure chambers through which pressure acts on the liquid discharged from the multiple outlets, A plurality of common supply channels extend along the direction of arrangement of the discharge port rows and supply liquid to the plurality of pressure chambers, A plurality of common recovery channels extend along the direction of arrangement of the discharge port rows and recover liquid from the plurality of pressure chambers, A distribution channel for distributing liquid to the aforementioned multiple common supply channels, A collection channel for collecting liquid from the aforementioned multiple common collection channels, A liquid dispensing head having, A circulation pump that circulates the liquid in the order of the distribution channel, the common supply channel, the pressure chamber, the common recovery channel, and the aggregation channel, A bypass opening connects the common supply channel and the aggregate channel without going through the pressure chamber, A liquid dispensing head characterized by having the following features.

2. The collection opening row comprises a plurality of collection openings arranged to connect the common collection channel and the aggregation channel, The liquid dispensing head according to claim 1, wherein the bypass opening is formed between the plurality of recovery openings in the direction of arrangement of the row of recovery openings.

3. The common supply channel and the aggregated channel are connected by a row of supply openings arranged in a line, The liquid dispensing head according to claim 1, wherein the bypass opening is formed between the plurality of supply openings in the direction of arrangement of the supply opening row.

4. The liquid discharge head according to claim 1, wherein the opening shape of the bypass opening is elliptical.

5. Having a common supply channel array formed by arranging the aforementioned plurality of common supply channels, The liquid discharge head according to claim 1, wherein the length of the common supply channel in the direction of arrangement of the common supply channel row is 250 μm or less.

6. Having a common recovery channel array in which the plurality of common recovery channels are arranged, The liquid discharge head according to claim 1, wherein the length of the common recovery channel in the direction of arrangement of the row of common recovery channels is 250 μm or less.

7. The liquid discharge head according to claim 1, wherein the amount of pure water that the circulation pump can deliver per unit time at 25°C is 2000 mL / min or less.

8. The aforementioned circulation pump has a pump chamber that functions as a pump, The amount of pure water that the circulation pump can deliver per unit time at 25°C is equal to the volume of the pump chamber (1 cm³). ３ The liquid dispensing head according to claim 1, wherein the dispensing rate is 25 mL / min or less per unit.

9. The aforementioned circulation pump has a pump chamber that functions as a pump, The amount of pure water that the circulation pump can deliver per unit time at 25°C is equal to the volume of the pump chamber (1 cm³). ３ The liquid dispensing head according to claim 1, wherein the dispensing rate is 0.003 mL / min or more per unit.

10. The liquid dispensing head according to claim 1, wherein at 25°C, the viscosity of the liquid discharged from the discharge port is 0.89 cps or more and 30 cps or less.

11. The distribution channel and the aggregation channel each have a plurality of, The liquid discharge head according to claim 1, wherein the distribution channel and the aggregation channel are alternately aligned in the direction of the arrangement of the discharge port row.

12. A discharge substrate having the plurality of discharge port rows, the plurality of pressure chambers, the plurality of common supply channels, and the plurality of common recovery channels formed therein, A support substrate that supports the discharge substrate, A plate-shaped member interposed between the discharge substrate and the support substrate, which becomes part of the wall surface of the plurality of common supply channels and the plurality of common recovery channels, It has, The support substrate has the distribution channel and the aggregation channel formed therein. The liquid discharge head according to claim 1, wherein the plate-shaped member has the bypass opening formed therein.

13. The liquid discharge head according to claim 12, wherein the plate-shaped member has a recovery opening that connects the aggregation channel and the common recovery channel, and the opening diameter of the bypass opening is smaller than the opening diameter of the recovery opening.

14. The liquid discharge head according to claim 12, wherein the plate-shaped member has a supply opening that connects the distribution channel and the common supply channel, and the opening diameter of the bypass opening is smaller than the opening diameter of the supply opening.

15. Having multiple of the aforementioned aggregation channels, The system includes a bubble storage channel connected to the aforementioned plurality of aggregation channels, The liquid discharge head according to claim 1, wherein the bubble storage channel is provided with a bent portion for storing bubbles.

16. The bubble storage channel is provided with a first section and a second section. In the operating state of the liquid dispensing head, the second portion is located vertically above the first portion. The liquid dispensing head according to claim 15, wherein in a predetermined direction, the length of the second portion is longer than the length of the first portion.

17. The liquid dispensing head according to claim 1, A carriage for mounting the aforementioned liquid dispensing head, A liquid dispensing device having, The liquid dispensing device is characterized in that the carriage moves relative to the recording medium from which the liquid is dispensed from the liquid dispensing head.

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