Liquid dispensing head

Abstract

To provide a liquid discharge head configured to suppress clogging of an end part of a common passage with bubbles.SOLUTION: A liquid discharge head comprises a discharge port row, a pressure chamber, a common supply passage, a supply port row formed of arranged supply ports, a common recovery passage, and a recovery port row formed of arranged recovery ports. The supply port row and the recovery port row extend from one end side 300a of the liquid discharge head toward the other end side 300b thereof. The plurality of recovery ports included in the recovery port row includes one end part recovery port 311a arranged closest to the one end side and the other end part recovery port 312b arranged closest to the other end side. When viewed from a position opposing to an opening of the discharge port, a portion of an opening of the one end part recovery port overlaps with at least a portion of an end part 321a at the one end side of the common recovery passage, and a portion of an opening of the other end part recovery port overlaps with at least a portion of an end part 322b at the other end side of the common recovery passage.SELECTED DRAWING: Figure 5

Description

Technical Field

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

Background Art

[0002] In the recent field of inkjet printers, there is a demand for liquid ejection apparatuses capable of outputting high-quality printed matter. However, if the ejection ports for ejecting liquid remain in a state of being exposed to air for a long time, the evaporation of the liquid causes the liquid to thicken, which in turn leads to ejection failures, making it impossible to output high-quality printed matter. Accordingly, in order to suppress the thickening of the liquid due to such evaporation, a circulation-type liquid ejection apparatus that circulates the liquid is known.

[0003] For example, Patent Document 1 discloses a liquid ejection head that circulates liquid through a plurality of pressure chambers corresponding to a plurality of ejection ports by providing a common supply flow path and a common recovery flow path in the ejection port array when the ejection ports are arranged at high density. Such liquid circulation is realized by joining a liquid flow control plate to a substrate on which flow path grooves are formed to form flow paths, and joining openings provided in the liquid flow control plate to a supply and recovery mechanism.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of Invention

Problems to be Solved by the Invention

[0005] However, in the configuration of Patent Document 1, the opening formed at the end of the liquid discharge head, which is either a supply port for supplying liquid to a common supply channel or a recovery port for recovering liquid from a common recovery channel, is formed further inward from the end of the respective common channel. In other words, a dead end is formed at the end of the common supply channel or common recovery channel. In such areas within the common supply channel or common recovery channel, liquid flow is difficult to generate, and foam mixed into the channel or foam generated within the channel tends to accumulate. The accumulated foam gradually grows, potentially causing printing defects due to blockage of the channel.

[0006] In view of the above problems, the present invention aims to provide a liquid discharge head that suppresses blockage by foam at the end of a common flow path. [Means for solving the problem]

[0007] To solve the above problems, the present invention provides a liquid discharge head having a discharge port row comprising a plurality of discharge ports arranged therein for discharging liquid, a plurality of pressure chambers communicating with each of the plurality of discharge ports, a common supply channel for supplying liquid to the plurality of pressure chambers, a supply port row comprising a plurality of supply ports arranged therein for supplying liquid to the common supply channel, a common recovery channel for recovering liquid from the plurality of pressure chambers, and a recovery port row comprising a plurality of recovery ports arranged therein for recovering liquid from the common recovery channel, wherein the supply port row and the recovery port row extend from one end to the other end of the liquid discharge head, the plurality of recovery ports included in the recovery port row include a one-end recovery port located furthest to the one end and a other-end recovery port located furthest to the other end, and when viewed from a position opposite to the opening of the discharge port, a part of the opening of the one-end recovery port overlaps with at least a part of the end of the common recovery channel on the one end side, and a part of the opening of the other-end recovery port overlaps with at least a part of the end of the common recovery channel on the other end side. Furthermore, a portion of at least one of the openings of the one-end recovery port or the other-end recovery port is formed outside the common recovery channel beyond the one-end or the other-end of the common recovery channel, and the length of the liquid discharge head of the one-end recovery port or the other-end recovery port in the extending direction in the portion formed outside the common recovery channel beyond the one-end or the other-end of the common recovery channel is longer than the vertical length of the common recovery channel. It is characterized by the following: [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a liquid discharge head that suppresses blockage by bubbles at the end of the common flow path. [Brief explanation of the drawing]

[0009] [Figure 1] Schematic diagram of a liquid dispensing device. [Figure 2] Schematic diagram of the liquid dispensing head. [Figure 3] A schematic diagram showing the circulation path in the discharge unit. [Figure 4] A cross-sectional view showing the liquid flow in the discharge unit. [Figure 5] Schematic diagram of the liquid dispensing head. [Figure 6] Schematic diagram of the liquid dispensing head. [Figure 7] Schematic diagram of the liquid dispensing head. [Figure 8] Schematic diagram of the liquid dispensing head. [Figure 9] Enlarged view of the collection port at one end and the surrounding area. [Figure 10] Enlarged view of the collection port at one end and the surrounding area. [Figure 11] Enlarged view of the collection port at one end and the surrounding area. [Figure 12] Enlarged view of the collection port at one end and the surrounding area. [Figure 13] Schematic diagram of the liquid dispensing head in the comparative example. [Modes for carrying out the invention]

[0010] Examples of each embodiment 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] (First embodiment) Figure 1 is a schematic perspective view of a liquid ejection apparatus 50 using a liquid ejection head 1. The liquid ejection apparatus 50 of the present embodiment constitutes a serial-type inkjet recording apparatus that performs recording on a recording medium P by ejecting ink as a liquid while scanning the liquid ejection head 1. It should be noted that a so-called full-line type liquid ejection head, in which ejection ports are formed over the entire width direction of the recording medium P and ejection can be performed over the entire width direction of the recording medium P without accompanying movement in the main scanning direction described later, may also be used.

[0012] The liquid ejection head 1 is mounted on a mounting portion (carriage 60). The carriage 60 reciprocates along the guide shaft 51 in the main scanning direction (X direction). The recording medium P is conveyed by conveying rollers 55, 56, 57, 58 in the sub-scanning direction (Y direction) that intersects (in this example, is orthogonal to) the main scanning direction. The liquid ejection head 1 is configured to be removable from and attachable to the carriage 60 by a user.

[0013] The liquid ejection head 1 is configured to include a circulation unit 54 and an ejection unit 3 to be described later. Although the specific configuration will be described later, the ejection unit 3 is provided with a plurality of ejection ports for ejecting liquid, and energy generating elements that generate ejection energy for ejecting liquid from each ejection port.

[0014] Further, the liquid ejection apparatus 50 is provided with an ink tank 2 which is an ink supply source and an external pump 21, and the ink stored in the ink tank 2 is supplied to the circulation unit 54 via the ink supply tube 59 by the driving force of the external pump 21.

[0015] The liquid ejection apparatus 50 forms a predetermined image on the recording medium P by repeating a recording scan in which the liquid ejection head 1 mounted on the carriage 60 ejects ink to perform recording while reciprocating in the main scanning direction, and a conveying operation that conveys the recording medium P in the sub-scanning direction. Note that the liquid ejection head 1 in the present embodiment is capable of ejecting four types of ink, namely black (K), cyan (C), magenta (M), and yellow (Y), and can record full-color images with these inks. However, the inks that can be ejected from the liquid ejection head 1 are not limited to the above four types of inks. The present invention is also applicable to liquid ejection heads for ejecting other types of ink. That is, the type and number of inks ejected from the liquid ejection head are not limited. In addition, a cap member (not shown) is disposed at a position deviated from the conveyance path of the recording medium P, and when the recording operation is not performed, the cap member relatively moves to a position covering the face surface of the liquid ejection head 1, so as to prevent the ejection ports from drying, and perform suction operations for filling and recovery.

[0016] FIG. 2 shows a schematic diagram of the liquid ejection head. FIG. 2(a) shows a schematic perspective view of the liquid ejection head. FIG. 2(c) is a view of the liquid ejection head as seen from the direction of arrow A in FIG. 2(a). The outer shape of the liquid ejection head 1 is constituted by a housing 110 and a support member 210. FIG. 2(b) shows an exploded perspective view of the liquid ejection head. The liquid ejection head 1 has four circulation units 54 corresponding to the four types of ink. The circulation unit 54 is composed of circulation units 54a to 54d respectively corresponding to each ink, and each of the circulation units 54a to 54d is connected to the housing 110. The housing 110 includes a joint surface 111 on which joints 111a to 111d for receiving ink from the recording apparatus are formed, and the joints 111a to 111d respectively communicate with the circulation units 54a to 54d. When the liquid ejection head 1 is mounted on the recording apparatus, supply tubes 59 corresponding to the respective inks from the recording apparatus side are connected to the respective joints 111a to 111d. Each ink supplied from the supply tube 59 is supplied to the respective circulation units 54a to 54d via the joints 111a to 111d of the housing 110. Further, a plurality of circulation units 54 may be provided for the same type of liquid.

[0017] In Figure 2(b), the liquid discharge head 1 has a circulation unit 54. The circulation unit 54 is equipped with a pressure adjustment means (not shown) and a pump (not shown). As the pump, for example, a diaphragm pump can be used, but it is not limited to this; any pump capable of circulating liquid is acceptable. Furthermore, the liquid discharge head 1 does not necessarily have to have a circulation unit 54. That is, the liquid inside the liquid discharge head 1 may be circulated between the circulation unit located outside the liquid discharge head 1 and the externally located circulation unit.

[0018] A support member 210, on which an ejection module 300 (described later) is mounted, is connected to the bottom surface 113 of the housing 110. Ink supplied to the circulation units 54a to 54d is supplied to the support member 210 via the housing 110. In Figure 2(c), two ejection modules 300 are bonded to the support member 210, but there may be one ejection module 300, or three or more may be bonded. The ejection module 300 and the support member 210 are bonded together with adhesive. The ejection module 300 comprises a silicon substrate with a thickness of 0.5 to 1 mm and a plurality of energy generating elements 36 (Figure 4) provided on one side of the silicon substrate for ejecting liquid. In this embodiment, a heat-generating resistance element is used as the energy generating element 36, and heat is generated by supplying power to the heat-generating resistance element from the printed circuit board 230 via the electrical circuit board 220. Multiple pressure chambers corresponding to the heat-generating resistance elements and multiple ejection ports for ejecting ink are formed on the silicon substrate using photolithography technology. In this embodiment, a heat-generating resistance element is used as the energy generating element, but this is not the only option. That is, a dispensing method using a piezoelectric element (piezo) to discharge liquid, or any other dispensing method, can be employed.

[0019] Figure 3 is a schematic diagram showing the circulation path in the ejection unit 3. Figure 3(a) is an exploded perspective view of the ejection unit 3 seen from the support member 210 side, and Figure 3(b) is an exploded perspective view of the ejection unit 3 seen from the nozzle plate 330 side. The ink flow path within the ejection unit 3 is composed of the support member 210 and the ejection module 300. The arrows shown in Figure 3 indicate the circulating flow of liquid within the ejection unit 3. Solid arrows represent the flow of liquid supplied from the support member 210 to the ejection module 300, and dashed arrows represent the flow of liquid recovered from the ejection module 300 to the support member 210. The ink flow is explained for only one color, but the process is similar for other colors.

[0020] The support member 210 has multiple support member supply ports 212 and multiple support member recovery ports 211. Liquid supplied from the liquid discharge device 50 to the liquid discharge head 1 or from the circulation unit 54 is supplied to the discharge module 300 via the support member supply ports 212. Liquid that is not discharged by the discharge module 300 is recovered by the circulation unit 54 via the support member recovery ports 211. In this case, if the liquid discharge head 1 does not have a circulation unit 54, the liquid may be recovered by a circulation unit outside the liquid discharge head.

[0021] The discharge module 300 is the part that functions as a liquid discharge head, and the discharge module 300 itself is also referred to as the liquid discharge head. The discharge module 300 is constructed by stacking an opening plate 310, a flow path plate 320, and a nozzle plate 330 in that order from the support member 210 side. These plates are joined together so that the flow paths of each liquid are in communication, forming the discharge module 300, which is then supported by the support member 210.

[0022] The opening plate 310 has a row of supply ports 312 that communicate with the support member supply port 212 and a row of recovery ports 311 that communicate with the support member recovery port 211, both arranged on the side facing the support member 210. The row of supply ports refers to a row of multiple supply ports that supply liquid to a common supply channel 322, which will be described later. Similarly, the row of recovery ports refers to a row of multiple recovery ports that recover liquid from a common recovery channel 321, which will be described later. In addition, although multiple supply ports 312 and recovery ports 311 are formed in Figure 3, there may also be a configuration in which only one of each is formed, or there may be multiple of one and only one of the other.

[0023] On the opening plate 310 side of the flow path plate 320, there is a common supply flow path 322 (Figure 4) that communicates with the supply port 212 and a common recovery flow path 321 (Figure 4) that communicates with the recovery port 211. On the nozzle plate 330 side of the flow path plate 320, there is an individual supply flow path 324 that connects the common supply flow path 322 to the pressure chamber 325 (Figure 4) formed in the nozzle plate 330, and an individual recovery flow path 323 that connects the common recovery flow path 321 to the pressure chamber 325. The nozzle plate 330 also has a row of discharge ports 331 arranged in a sequence for discharging liquid, and each of the multiple discharge ports communicates with multiple pressure chambers 325. The pressure generated by the energy generating element 36 in the pressure chamber 325 acts on the liquid, causing the liquid to be discharged from the discharge ports 331. The liquid that is not discharged is recovered from the pressure chamber 325 via the individual recovery flow path 323 to the common recovery flow path 321 and the recovery port 311.

[0024] In other words, the liquid in the discharge module 300 circulates in the following order: supply port 312, common supply channel 322, individual supply channel 324, pressure chamber 325, individual recovery channel 323, common recovery channel 321, and recovery port 311. Thus, the formation of the common supply channel 322 and individual supply channel 324 allows the liquid flowing from the supply port 312 to be guided to the location where the discharge port 331 is formed. Similarly, the formation of the common recovery channel 321 and individual recovery channel 323 allows the liquid not discharged from the discharge port 331 to be guided to the location where the recovery port 311 is formed. Here, the supply port 312 and recovery port 311 of the opening plate 310 are formed in a staggered pattern. If they are not formed in a staggered pattern, the supply port 312 and recovery port 311 may be formed in a straight line parallel to each other, as shown in Figure 7, which will be described later. In this case, the length of the liquid discharge head in the X direction (short side direction) increases, so from the viewpoint of manufacturing costs, it is preferable to form the supply port 312 and recovery port 311 in a staggered pattern.

[0025] Figures 4(a) to 4(c) are cross-sectional views showing the ink flow in different parts of the discharge unit 3. Figure 4(a) is the cross-section indicated by AA in Figure 3(a), showing the cross-section of the part of the discharge unit 3 where the support member supply port 212 and supply port 312 are in communication. Figure 4(b) is the cross-section indicated by BB in Figure 3(a), showing the cross-section of the part of the discharge unit 3 where the support member recovery port 211 and recovery port 311 are in communication. Figure 4(c) is the cross-section indicated by CC in Figure 3(a), showing the cross-section of the part where the supply port 312 and recovery port 311 are not in communication with the flow path of the support member 210.

[0026] In the liquid supply channel, as shown in Figure 4(a), liquid is supplied from the overlapping and communicating portion of the support member supply port 212 of the support member 210 and the supply port 312 of the opening plate 310. In the liquid recovery channel, as shown in Figure 4(b), ink is recovered from the overlapping and communicating portion of the support member recovery port 211 of the support member 210 and the recovery port 311 of the opening plate 310. When liquid circulation is stopped, liquid diffusion occurs, supplying liquid from the recovery channel side to the pressure chamber 325 in response to evaporation of liquid from the discharge port. As shown in Figure 4(c), in the discharge unit 3, there are areas where the opening plate 310 does not have an opening. In such areas, liquid is not supplied or recovered between the support member 210 and the discharge module 300. Liquid is supplied in the areas where the supply port 312 is provided, as shown in Figure 4(a), and liquid is recovered in the areas where the recovery port 311 is provided, as shown in Figure 4(b).

[0027] Because the discharge port 331 is located within the path connecting the individual supply channel 324 and the individual recovery channel 323, a flow occurs in the pressure chamber 325 near the discharge port 331 from the individual supply channel side to the individual recovery channel side. Since this flow occurs throughout the entire row of discharge ports, the liquid circulation efficiency is improved, keeping the liquid in the pressure chamber 325 constantly fresh and preventing problems such as viscosity increase and solidification due to evaporation.

[0028] Figure 13 shows the configuration of a comparative example. Figure 13(a) is a schematic diagram of the opening plate 810 viewed from the support member side, and Figure 13(b) is a schematic diagram of the flow channel plate 820 viewed from the support member side (opening plate 810 side). Figure 13(c) is a schematic cross-sectional view in the Y direction including the supply port 812 when the opening plate 810 and the flow channel plate 820 are joined together. The opening plate 810 has a row of supply ports 812 arranged therein and a row of recovery ports 811 arranged therein. On the opening plate side of the flow channel plate 820, there is a common supply channel 822 communicating with the supply ports 812 and a common recovery channel 821 communicating with the recovery ports 811. On the back side of the flow channel plate 820, there are individual supply channels 824 and individual recovery channels 823 that connect the common supply channel 822 and the common recovery channel 821 to the pressure chamber, respectively. Furthermore, the arrows in Figure 13(c) schematically represent the flow of the liquid.

[0029] Generally, foam 880 that flows in from the supply port 812 or is generated in the flow path moves to the housing 110 by buoyancy, or is removed from the liquid discharge head via the discharge port by a recovery mechanism provided in the recording device. However, in the configuration of Figure 13, the supply ports 812 located at both ends of the row of supply ports extending in the longitudinal direction (Y direction) of the liquid discharge head are formed inward from the longitudinal (Y direction) end of the common supply flow path 822, so a dead end exists at the end of the common supply flow path 822. Liquid is supplied mainly from two supply ports 812 to areas other than the end of the common supply flow path 822, whereas liquid is supplied to the dead end located at the end mainly from one supply port 812 located at the end. Furthermore, the flow of liquid in the common supply flow path 822 is blocked by the flow path wall of the dead end located at the end. Therefore, liquid flow is less likely to occur in the dead end located at the end of the common supply flow path 822. Therefore, if foam accumulates in the dead ends, it is difficult for it to move towards the casing due to buoyancy, and it is also difficult for it to be discharged by the recovery operation of the recording device. Moreover, as the foam gradually accumulates in the dead ends and grows, it can block the flow path, potentially causing printing defects.

[0030] Furthermore, in Figure 13, the recovery ports 811 located at both ends of the row of recovery ports extending in the longitudinal direction (Y direction) of the liquid discharge head are formed inward from the end of the common recovery channel 821 in the longitudinal direction (Y direction). Therefore, a dead end also exists at the end of the common recovery channel 821. Consequently, the above phenomenon may similarly occur in the recovery channel.

[0031] In a circulating liquid discharge head, there is a flow of liquid circulation by the circulation unit and a flow of liquid refilling when liquid is discharged from the discharge port. The flow of liquid circulation occurs from the supply channel side toward the recovery channel, while the flow of liquid refilling occurs in the direction of being drawn into the discharge port. In the supply channel, the direction of liquid circulation and the direction of being drawn into the discharge port are the same, whereas in the recovery channel, the direction of liquid circulation and the direction of being drawn into the discharge port are opposite. That is, in the recovery channel, the flow in the direction of liquid circulation (towards the support member 210) and the flow drawn into the discharge port due to liquid discharge cancel each other out. Therefore, liquid flow is less likely to occur in the recovery channel relative to the supply channel, and foam is more likely to accumulate at the end of the common recovery channel 821 than at the end of the common supply channel 822.

[0032] In contrast to the comparative example described above, Figure 5 shows the configuration of the liquid discharge head in the first embodiment. Figure 5(a) is a schematic view of the opening plate 310 as seen from the support member 210 side, and Figure 5(b) is a schematic view of the flow path plate 320 as seen from the support member 210 side (opening plate 310 side). Figure 5(c) is a schematic cross-sectional view in the Y direction including the recovery port 311 when the opening plate 310 and the flow path plate 320 are joined together, and Figure 5(d) is an enlarged view of region A in Figure 5(b). The supply port row consisting of a plurality of supply ports 312 and the recovery port row consisting of a plurality of recovery ports 311 are formed to extend in the Y direction from one end side 300a to the other end side 300b of the discharge module 300 (liquid discharge head). The plurality of supply ports 312 included in the supply port row include the one-end supply port 312a located at the one end side 300a and the other-end supply port 312b located at the other end side 300b. Furthermore, the multiple collection ports 311 included in the collection port row include one-end collection port 311a located at the one end 300a and another-end collection port 311b located at the other end 300b.

[0033] In this embodiment, as shown in Figure 5(d), a portion of the opening of the recovery port 311 closest to one end of the liquid discharge head overlaps with at least a portion of the end 321a at one end of the common recovery channel. Furthermore, although not shown in the figure, a portion of the opening of the recovery port closest to the other end 300b of the liquid discharge head overlaps with at least a portion of the end 321b at the other end of the common recovery channel. In other words, when viewed from a position opposite the discharge port opening, a portion of the opening of the one-end recovery port 311a overlaps with at least a portion of the end at one end of the common recovery channel, and a portion of the opening of the other-end recovery port 311b overlaps with at least a portion of the end at the other end of the common recovery channel. With this configuration, dead ends are not formed at both ends of the common recovery channel 321, and the flow of liquid is not easily obstructed. Therefore, the accumulation of foam 380 at the ends of the common recovery channel 321 is suppressed. Even if bubbles are present in the end region, they are easily moved to the housing 110 by buoyancy and easily discharged to the outside of the liquid discharge head via the discharge port 331 by the recovery operation of the recording device. Therefore, blockage by bubbles at the end of the common recovery channel 321 can be suppressed, and consequently, discharge failures can be suppressed.

[0034] In this embodiment, the supply port 312 may have the above configuration instead of the recovery port 311. Figure 6 is a schematic diagram of the liquid discharge head when the above concept is applied to the supply port 312. Figure 6(a) is a schematic diagram of the opening plate 310 viewed from the support member 210 side, and Figure 6(b) is a schematic diagram of the flow path plate 320 viewed from the support member 210 side (opening plate 310 side). Figure 6(c) is a schematic cross-sectional view in the Y direction including the supply port 312 when the opening plate 310 and the flow path plate 320 are joined together, and Figure 6(d) is an enlarged view of region B in Figure 6(b).

[0035] In Figure 6(d), a portion of the opening of the supply port 312 closest to one end 300a of the liquid discharge head overlaps with at least a portion of the end 322a of the common supply channel. Furthermore, although not shown in the figure, a portion of the opening of the supply port closest to the other end 300b of the liquid discharge head overlaps with the end 322 of the common supply channel. In other words, when viewed from a position opposite the discharge port opening, a portion of the opening of the one-end supply port 312a overlaps with at least a portion of the end 322a of the common supply channel, and a portion of the opening of the other-end supply port 312b overlaps with at least a portion of the end 322b of the common supply channel. With this configuration, as with the common recovery channel, dead ends are not formed at both ends of the common supply channel 322, and the flow of liquid is less likely to be obstructed. Therefore, the accumulation of foam 380 at the ends of the common supply channel 322 is suppressed. Even if bubbles are present in the end region, they are easily moved to the housing 110 by buoyancy and easily discharged to the outside of the liquid discharge head via the discharge port 331 by the recovery operation of the recording device. Therefore, blockage by bubbles at the end of the common supply channel 322 can be suppressed, and consequently, discharge failures can be suppressed.

[0036] Here, the opening of the supply port 312 and the opening of the recovery port 311 in this embodiment refer to a flow path portion through which liquid can communicate and the edge portion surrounding that flow path portion. That is, for example, when a part of the opening of the one-end recovery port 311a overlaps with the one-end portion 321a of the common recovery flow path, it includes the case where the edge portion of the one-end recovery port 311a overlaps with the one-end portion 321a of the common recovery flow path, as shown in Figure 5(d).

[0037] Furthermore, due to manufacturing errors in the liquid discharge head, there may be cases where a portion of the recovery port opening does not slightly overlap with the end of the common recovery channel. Even in such cases, it is sufficient that no dead ends are formed at both ends of the common recovery channel where foam accumulates. For example, it is sufficient that the distance between the one-end recovery port 311a and the one-end end 321a of the common recovery channel is smaller than the lengths L1 and L2 (Figure 5(d)) from the one-end recovery port 311a to the Y-direction (longitudinal direction) end of the common recovery channel (recovery adjacent end 321c).

[0038] Furthermore, the risk of foam generation can also be reduced by degassing the liquid. However, a mechanism for degassing the liquid requires a pressure reduction mechanism such as a pump, which leads to an increase in the size of the recording device. Also, in the configuration in this embodiment, where a circulation unit is provided on the liquid ejection head 1, a degassing mechanism needs to be provided on the liquid ejection head, but scanning the head including the degassing mechanism is difficult in a serial type recording device. According to this embodiment, since printing defects caused by blockage of the circulation channel due to foam can be effectively reduced without resorting to the above means, it is preferable to adopt the liquid ejection head of this embodiment in a serial type recording device.

[0039] Furthermore, as mentioned above, in the recovery channel, the direction in which the liquid circulates via the circulation unit and the direction in which the liquid is drawn into the discharge port via discharge are opposite, making the liquid flow more easily obstructed compared to the supply channel. For this reason, if either the supply channel or the recovery channel is configured as described above, it is preferable to configure the recovery channel as described above.

[0040] Furthermore, in terms of suppressing foam stagnation at the ends of the common channel in the present invention, it is more preferable to have a configuration in which no dead ends are formed at the ends of the common supply channel and the common recovery channel, as shown in Figures 7(a) and 7(b). As a result, since no dead ends are formed at the ends of both the common supply channel 322 and the common recovery channel 321, blockage by foam at the ends of the common channel can be further suppressed.

[0041] With the above configuration, no dead ends are formed in the common flow path from the supply port or recovery port to the discharge port, thus suppressing blockage due to foam in the common recovery flow path and common supply flow path, and consequently, discharge failure.

[0042] (Second embodiment) The configuration of the liquid discharge head in the second embodiment of the present invention will be described. In the following description, only the parts that differ from the first embodiment will be described, and parts that are the same as in the first embodiment will not be described.

[0043] Figure 8 shows the configuration of the liquid discharge head, which is the second embodiment. Figure 8(a) is a schematic view of the opening plate 310 as seen from the support member 210 side, and Figure 8(b) is a schematic view of the flow path plate 320 as seen from the support member 210 side (opening plate 310 side). Figure 8(c) is a schematic cross-sectional view in the Y direction including the recovery port 311 when the opening plate 310 and the flow path plate 320 are joined together, and Figure 8(d) is an enlarged view of region C in Figure 8(b).

[0044] In this embodiment, as shown in Figure 8(d), a portion of the opening of the one-end recovery port 311a closest to one end 300a of the liquid discharge head is formed outside the common recovery channel beyond the one-end 321a of the common recovery channel. Similarly, a portion of the opening of the other-end recovery port 311b closest to the other end 300b of the liquid discharge head may be formed outside the common recovery channel beyond the other-end 321b of the common recovery channel. In other words, in this embodiment, it is preferable that a portion of at least one of the openings of the one-end recovery port 311a or the other-end recovery port 311b is formed outside the common recovery channel beyond the one-end 321a or the other-end 321b of the common recovery channel. The length w of the portion of the recovery port 311 located at the end that is formed outside the common recovery channel 321 in the extending direction of the liquid discharge head is, for example, 5 μm. The length w can be set appropriately in consideration of manufacturing variations during the production of the liquid discharge head.

[0045] Even with this configuration, no dead end is formed at the end of the common recovery channel 321, and the flow of liquid is less likely to be obstructed. Furthermore, compared to the first embodiment, the risk of the recovery port 311 located at the end being formed inside the common recovery channel 321 due to manufacturing errors of the liquid discharge head can be reduced. Moreover, it is more preferable that both the recovery port 311a at one end and the recovery port 311b at the other end, rather than just one of them, have the above configuration.

[0046] Furthermore, multiple bubbles generated in the flow path aggregate and grow along the flow path wall into a large, approximately spherical bubble, reducing its surface area due to surface tension. When the bubble grows to include the stepped portion between the one-end recovery port 311a and the common recovery flow path 321, if the length w is longer than the vertical length h of the common recovery flow path, the bubble will follow the wall of the recovery port and deviate from its approximately spherical shape. When the shape deviates significantly from the approximately spherical shape, and the approximately spherical shape would result in a smaller surface area, the bubble will detach from the wall and become approximately spherical again, moving to the housing or being discharged outside the liquid discharge head via the discharge port. In other words, if the length w is longer than the vertical length h of the common recovery flow path, the accumulation of bubbles at the end of the common recovery flow path 321 can be further suppressed. In other words, it is preferable that the length in the extending direction of the liquid discharge head of the one-end recovery port or the other-end recovery port in the portion formed outside the common recovery channel beyond the one-end 321a or the other-end 321b of the common recovery channel is longer than the vertical length of the common recovery channel.

[0047] In this embodiment, the recovery port 311 was described as an example, but the accumulation of foam at the end of the common supply channel 322 can also be suppressed by configuring the supply port 312 as described above. That is, a portion of at least one of the openings of the one-end supply port 312a or the other-end supply port 312b may be formed outside the common supply channel beyond the one-end 322a or the other-end 322b of the common supply channel. Furthermore, it is preferable that the length in the extending direction of the liquid discharge head of the one-end supply port or the other-end supply port in the portion formed outside the common supply channel beyond the one-end 322a or the other-end 322b of the common supply channel is longer than the vertical length of the common supply channel. Moreover, it is more preferable that both, not just one of the one-end supply port 312a or the other-end supply port 312b, have the above configuration.

[0048] With the above configuration, it is possible to suppress the formation of the supply port or recovery port further inside the common supply channel or common recovery channel due to manufacturing errors, and to make it easier to remove foam accumulated at the end of the common channel. In addition, both the recovery port 311 and the supply port 312 may be configured in the manner of this embodiment.

[0049] (Third embodiment) The configuration of the liquid discharge head in the third embodiment of the present invention will now be described. Figure 9 is an enlarged view of the one-end recovery port 311a and its vicinity in the third embodiment. In this embodiment, a portion of the opening of at least one of the one-end recovery port 311a or the other-end recovery port 311b overlaps with at least a portion of the adjacent recovery end 321c that is adjacent to both ends of the common recovery flow path, as well as the one-end and other-end ends of the common recovery flow path. According to this embodiment, since the one-end recovery port 311a also overlaps with at least a portion of the adjacent recovery end 321c, no dead end is formed at the short-side end. Therefore, the risk of foam accumulating at the short-side end is reduced, and blockage of the flow path by foam can be further suppressed. Furthermore, it is more preferable to have both the one-end recovery port 311a and the other-end recovery port 311b, rather than just one of them, configured as described above.

[0050] In this embodiment, the recovery port 311 was described as an example, but the supply port 312 can also be configured as described above. That is, a portion of at least one of the openings of the one-end supply port 312a or the other-end supply port 312b may overlap with at least a portion of the supply adjacent end 322c adjacent to both ends of the common supply channel, as well as the ends on the one-end and other-end sides of the common supply channel. With such a configuration, the risk of foam accumulation at the short-side end of the common supply channel 322 is reduced, and blockage of the channel by foam can be further suppressed. Furthermore, it is more preferable to have both the one-end supply port 312a and the other-end supply port 312b, rather than just one of them, configured as described above.

[0051] In the above configuration, no dead ends are formed at the ends in the short direction of the common flow path. This reduces the risk of foam accumulation at the short end and further suppresses blockage of the flow path by foam. Furthermore, both the supply port and the collection port may be configured as described above.

[0052] (Fourth embodiment) The configuration of the liquid discharge head in the fourth embodiment of the present invention will now be described. Figure 10 is an enlarged view of the one-end recovery port 311a and its vicinity in the fourth embodiment. In the fourth embodiment, a portion of at least one of the openings of the one-end recovery port 311a or the other-end recovery port 311b overlaps with at least a portion of the end of the common recovery channel and is formed outside the common recovery channel than the adjacent recovery port 321c. This suppresses foam accumulation even at the end in the short direction of the common recovery channel and reduces the risk that, due to manufacturing errors of the liquid discharge head, the recovery port that overlaps with the adjacent recovery port 321c may be formed inside the common recovery channel than the adjacent recovery port 321c. Furthermore, it is more preferable to have both the one-end recovery port 311a and the other-end recovery port 311b, rather than just one of them, have the above configuration.

[0053] Figure 11 shows a modified example of the liquid discharge head, which is the fourth embodiment, and is an enlarged view of the one-end recovery port 311a and its vicinity. In this modified example, a portion of at least one of the openings of the one-end recovery port 311a or the other-end recovery port 311b overlaps with at least a portion of the adjacent recovery port 321c, and is formed outside the common recovery channel beyond the one-end port 321a or the other-end port 321b of the common recovery channel. This suppresses foam accumulation even at the ends in the short-side direction of the common recovery channel and reduces the risk that the recovery port located at the end will be formed inside the common recovery channel beyond the end of the common recovery channel due to manufacturing errors of the liquid discharge head.

[0054] Furthermore, by adopting the above-described configuration for the supply channel, similar effects can be obtained in the supply channel. That is, a portion of at least one of the openings of the one-end supply port 312a or the other-end supply port 312b may be formed outside the common supply channel beyond the adjacent supply port 322c. Alternatively, a portion of at least one of the openings of the one-end supply port 312a or the other-end supply port 312b may overlap with at least a portion of the adjacent supply port 322c and be formed outside the one-end port 322a or the other-end port 322b of the common supply channel. Moreover, when the supply channel and the recovery channel have the above-described configuration, it is more preferable because blockage by foam can be suppressed in both the supply channel and the recovery channel.

[0055] (Fifth embodiment) The configuration of the liquid discharge head in the fifth embodiment of the present invention will now be described. Figure 12 is an enlarged view of the one-end recovery port in the fifth embodiment. In the fifth embodiment, a portion of the opening of at least one of the one-end recovery port 311a or the other-end recovery port 311b is formed outside the common recovery channel beyond the end of the common recovery channel on either the one-end or the other-end side, and outside the common recovery channel beyond the plurality of adjacent recovery ends 321c. With this configuration, a dead end is not formed at the end of the liquid discharge head not only in the longitudinal direction but also in the transverse direction, so blockage by foam at the end of the common channel can be further suppressed. Furthermore, the risk of the recovery port 311 being formed inside the common recovery channel 321 due to manufacturing errors of the liquid discharge head can be reduced. Moreover, it is more preferable that both the one-end recovery port 311a and the other-end recovery port 311b, rather than just one of them, have the above configuration.

[0056] Furthermore, the same effect can be obtained by configuring the supply channel as described above. That is, a portion of the opening of at least one of the one-end supply port 312a or the other-end supply port 312b may be formed outside the common supply channel beyond the end of the common supply channel on either the one-end or the other-end side, and outside the common supply channel 322 beyond the multiple adjacent supply ends 322c. Moreover, it is more preferable that both the one-end supply port 312a and the other-end supply port 312b, rather than just one of them, have the above configuration. Furthermore, it is more preferable that the supply channel and the recovery channel have the above configuration because it is possible to suppress blockage by foam in both the supply channel and the recovery channel.

[0057] Furthermore, configurations that appropriately combine the settings of each of the embodiments described above are also applicable.

[0058] To summarize the present invention, it includes the following configuration.

[0059] (Composition 1) A liquid discharge head comprising: a row of discharge ports arranged therein for discharging liquid; a plurality of pressure chambers communicating with each of the plurality of discharge ports; a common supply channel for supplying liquid to the plurality of pressure chambers; a row of supply ports arranged therein for supplying liquid to the common supply channel; a common recovery channel for recovering liquid from the plurality of pressure chambers; and a row of recovery ports arranged therein for recovering liquid from the common recovery channel, wherein the row of supply ports and the row of recovery ports extend from one end to the other end of the liquid discharge head, the plurality of recovery ports included in the row of recovery ports include a one-end recovery port located furthest to the one end and a other-end recovery port located furthest to the other end, and when viewed from a position opposite to the opening of the discharge port, a portion of the opening of the one-end recovery port overlaps with at least a portion of the end of the common recovery channel on the one end side, and a portion of the opening of the other-end recovery port overlaps with at least a portion of the end of the common recovery channel on the other end side.

[0060] (Configuration 2) The liquid discharge head according to Configuration 1, wherein at least one part of the opening of the one-end recovery port or the other-end recovery port is formed outside the common recovery flow path, beyond the one-end or the other-end of the common recovery flow path.

[0061] (Composition 3) The liquid discharge head according to configuration 1 or 2, wherein the length in the extending direction of the liquid discharge head of the one-end recovery port or the other-end recovery port in the portion formed outside the common recovery channel beyond the one-end or the other-end of the common recovery channel is longer than the vertical length of the common recovery channel.

[0062] (Composition 4) The liquid discharge head according to any one of configurations 1 to 3, wherein the common recovery channel includes the end on one side and the adjacent recovery end adjacent to the end on the other side, and a part of the opening of at least one of the one end recovery port or the other end recovery port overlaps with at least a part of the adjacent recovery end.

[0063] (Composition 5) The liquid discharge head according to configuration 4, wherein a portion of the opening of at least one of the one end recovery port or the other end recovery port is formed outside the common recovery flow path than the adjacent recovery end.

[0064] (Composition 6) The liquid discharge head according to any one of configurations 1 to 3, wherein the common recovery channel includes a plurality of adjacent recovery ends adjacent to the one end and the other end, and a portion of the opening of at least one of the one end recovery port or the other end recovery port overlaps with at least a portion of the plurality of adjacent recovery ends.

[0065] (Composition 7) The liquid discharge head according to configuration 6, wherein at least one part of the opening of the one-end recovery port or the other-end recovery port is formed outside the common recovery flow path beyond the plurality of adjacent recovery ends.

[0066] (Composition 8) The plurality of supply ports included in the supply port row include an end supply port located furthest to one end and an end supply port located furthest to the other end, A liquid discharge head according to any one of configurations 1 to 7, wherein, when viewed from a position opposite to the discharge port opening, the opening of the one-end supply port or at least one of the openings of the other-end supply port overlaps with at least a portion of the one-end or the other-end of the common supply flow path.

[0067] (Composition 9) The liquid discharge head according to configuration 8, wherein at least one part of the opening of the one-end supply port or the other-end supply port is formed outside the common supply channel beyond the one-end or the other-end of the common supply channel.

[0068] (Composition 10) The liquid discharge head according to configuration 8 or 9, wherein the length in the extending direction of the liquid discharge head of the one-end supply port or the other-end supply port in the portion formed outside the common supply channel beyond the one-end or the other-end of the common supply channel is longer than the vertical length of the common supply channel.

[0069] (Composition 11) The liquid discharge head according to any one of configurations 8 to 10, wherein the common supply channel includes the one-end portion and the other-end portion adjacent to the supply adjacent portion, and a portion of the opening of at least one of the one-end supply port or the other-end supply port overlaps with at least a portion of the supply adjacent portion.

[0070] (Composition 12) The liquid discharge head according to configuration 11, wherein a portion of the opening of at least one of the one-end supply port or the other-end supply port is formed outside the common supply channel than the adjacent supply end.

[0071] (Composition 13) The liquid discharge head according to any one of configurations 8 to 10, wherein the common supply channel includes a plurality of adjacent supply ends adjacent to the one end and the other end, and a portion of the opening of at least one of the one end supply port or the other end supply port overlaps with at least a portion of the plurality of adjacent supply ends.

[0072] (Composition 14) The liquid discharge head according to configuration 13, wherein at least one part of the opening of the one-end supply port or the other-end supply port is formed outside the common supply flow path than the plurality of adjacent supply ends.

[0073] (Composition 15) A liquid discharge head having a row of discharge ports arranged therein for discharging liquid, a plurality of pressure chambers communicating with each of the plurality of discharge ports, a common supply channel for supplying liquid to the plurality of pressure chambers, and a row of supply ports arranged therein for supplying liquid to the common supply channel, wherein the row of supply ports extends from one end to the other end of the liquid discharge head, and the plurality of supply ports included in the row of supply ports include a one-end supply port located furthest to the one end and a other-end supply port located furthest to the other end, and when viewed from a position opposite to the opening of the discharge port, a portion of the opening of the one-end supply port overlaps with the one-end end of the common supply channel, and a portion of the opening of the other-end supply port overlaps with the other-end end of the common supply channel.

[0074] (Composition 16) The liquid discharge head according to configuration 15, wherein at least one part of the opening of the one-end supply port or the other-end supply port is formed outside the common supply channel beyond the one-end or the other-end of the common supply channel.

[0075] (Composition 17) The liquid discharge head according to configuration 15 or 16, wherein the length in the extending direction of the liquid discharge head of the one-end supply port or the other-end supply port in the portion formed outside the common supply channel beyond the one-end or the other-end of the common supply channel is longer than the vertical length of the common supply channel.

[0076] (Composition 18) The liquid discharge head according to any one of configurations 15 to 17, wherein the common supply channel includes the one-end portion and the other-end portion adjacent to the supply adjacent portion, and a portion of the opening of at least one of the one-end supply port or the other-end supply port overlaps with at least a portion of the supply adjacent portion.

[0077] (Composition 19) The liquid discharge head according to configuration 18, wherein a portion of the opening of at least one of the one-end supply port or the other-end supply port is formed outside the common supply channel than the adjacent supply end.

[0078] (Composition 20) A liquid dispensing head according to any one of configurations 1 to 19, further comprising a pump for circulating the liquid. [Explanation of Symbols]

[0079] 300 Dispensing Module (Liquid Dispensing Head) 300a Discharge module, one end 300b Other end of the discharge module 310 Opening Plate 311 Collection port 311a One end collection port 311b Other end collection port 312 Supply port 312a One end supply port 312b Other end supply port 320 flow path plate 321 Common recovery channel 321a End portion of the common recovery channel, one end 321b End of the common recovery channel on the other end 321c Recovery adjacent end 322 Common supply channel 322a End of one side of the common supply channel 322b The other end of the common supply channel 322c Supply adjacent end 323 Individual recovery channels 324 Individual supply channels

Claims

1. A series of outlets arranged to dispense liquid, Multiple pressure chambers communicating with each of the aforementioned multiple discharge ports, A common supply channel for supplying liquid to the aforementioned multiple pressure chambers, A row of supply ports is formed by arranging multiple supply ports for supplying liquid to the common supply channel, A common recovery channel for recovering liquid from the aforementioned multiple pressure chambers, A row of recovery ports is formed by arranging multiple recovery ports for recovering liquid from the aforementioned common recovery channel, In a liquid dispensing head having, The supply port row and the recovery port row extend from one end to the other end of the liquid discharge head. The plurality of collection ports included in the row of collection ports include an end collection port located furthest to one end and an end collection port located furthest to the other end, When viewed from a position opposite the opening of the discharge port, a portion of the opening of the one-end recovery port overlaps with at least a portion of the one-end side of the common recovery flow path, and a portion of the opening of the other-end recovery port overlaps with at least a portion of the other-end side of the common recovery flow path. A portion of at least one of the openings of the one-end recovery port or the other-end recovery port is formed outside the common recovery channel, A liquid discharge head characterized in that the length of the liquid discharge head in the extending direction of the one-end recovery port or the other-end recovery port in the portion formed outside the common recovery channel beyond the one-end or the other-end of the common recovery channel is longer than the vertical length of the common recovery channel.

2. The common recovery channel includes the one end and the other end, and the adjacent recovery end. The liquid discharge head according to claim 1, wherein a portion of the opening of at least one of the one end collection port or the other end collection port overlaps with at least a portion of the adjacent collection port.

3. The liquid discharge head according to claim 2, wherein a portion of the opening of at least one of the one end recovery port or the other end recovery port is formed outside the common recovery flow path than the adjacent recovery end.

4. The common recovery channel includes a plurality of adjacent recovery ends that are adjacent to the end on one side and the end on the other side. The liquid discharge head according to claim 1, wherein a portion of the opening of at least one of the one end collection port or the other end collection port overlaps with at least a portion of the plurality of adjacent collection ends.

5. The liquid discharge head according to claim 4, wherein at least one part of the opening of the one-end recovery port or the other-end recovery port is formed outside the common recovery flow path beyond the plurality of adjacent recovery ends.

6. A row of outlets arranged in a plurality of outlets for discharging liquid, Multiple pressure chambers communicating with each of the aforementioned multiple discharge ports, A common supply channel for supplying liquid to the aforementioned multiple pressure chambers, A row of supply ports is formed by arranging multiple supply ports for supplying liquid to the common supply channel, A common recovery channel for recovering liquid from the aforementioned multiple pressure chambers, A row of recovery ports is formed by arranging multiple recovery ports for recovering liquid from the aforementioned common recovery channel, In a liquid dispensing head having, The supply port row and the recovery port row extend from one end to the other end of the liquid discharge head. The plurality of collection ports included in the row of collection ports include an end collection port located furthest to one end and an end collection port located furthest to the other end, When viewed from a position opposite the opening of the discharge port, a portion of the opening of the one-end recovery port overlaps with at least a portion of the one-end side of the common recovery flow path, and a portion of the opening of the other-end recovery port overlaps with at least a portion of the other-end side of the common recovery flow path. The plurality of supply ports included in the supply port row include an end supply port located furthest to one end and an end supply port located furthest to the other end, A liquid discharge head characterized in that, when viewed from a position opposite to the discharge port opening, the opening of the one-end supply port or at least one of the openings of the other-end supply port overlaps with at least a portion of the one-end or the other-end of the common supply flow path.

7. The liquid discharge head according to claim 6, wherein a portion of at least one of the openings of the one-end supply port or the other-end supply port is formed outside the common supply channel beyond the one-end or the other-end of the common supply channel.

8. The liquid discharge head according to claim 7, wherein the length in the extending direction of the liquid discharge head of the one-end supply port or the other-end supply port in the portion formed outside the common supply channel beyond the one-end or the other-end of the common supply channel is longer than the vertical length of the common supply channel.

9. The common supply channel includes the one end and the other end, and the adjacent supply end. The liquid discharge head according to claim 6, wherein a portion of the opening at least one of the one-end supply port or the other-end supply port overlaps with at least a portion of the adjacent supply end.

10. The liquid discharge head according to claim 9, wherein a portion of the opening of at least one of the one-end supply port or the other-end supply port is formed outside the common supply channel than the adjacent supply end.

11. The common supply channel includes a plurality of adjacent supply ends that are adjacent to the end on one side and the end on the other side. The liquid discharge head according to claim 6, wherein a portion of the opening at least one of the one-end supply port or the other-end supply port overlaps with at least a portion of the plurality of adjacent supply ends.

12. The liquid discharge head according to claim 11, wherein at least one part of the opening of the one-end supply port or the other-end supply port is formed outside the common supply flow path than the plurality of adjacent supply ends.

13. A series of outlets arranged to dispense liquid, Multiple pressure chambers communicating with each of the aforementioned multiple discharge ports, A common supply channel for supplying liquid to the aforementioned multiple pressure chambers, A row of supply ports is formed by arranging multiple supply ports for supplying liquid to the common supply channel, In a liquid dispensing head having, The aforementioned supply port row extends from one end of the liquid discharge head toward the other end, The plurality of supply ports included in the supply port row include an end supply port located furthest to one end and an end supply port located furthest to the other end, When viewed from a position opposite the opening of the discharge port, a portion of the opening of the one-end supply port overlaps with at least a portion of the one-end side of the common supply flow path, and a portion of the opening of the other-end supply port overlaps with at least a portion of the other-end side of the common supply flow path. A portion of at least one of the openings of the one-end supply port or the other-end supply port is formed outside the common supply channel, A liquid discharge head characterized in that the length in the extending direction of the liquid discharge head of the one-end supply port or the other-end supply port in the portion formed outside the common supply channel beyond the one-end or the other-end of the common supply channel is longer than the vertical length of the common supply channel.

14. The common supply channel includes the one end and the other end, and the adjacent supply end. The liquid discharge head according to claim 13, wherein a portion of the opening at least one of the one-end supply port or the other-end supply port overlaps with at least a portion of the adjacent supply end.

15. The liquid discharge head according to claim 14, wherein a portion of the opening of at least one of the one-end supply port or the other-end supply port is formed outside the common supply channel than the adjacent supply end.

16. A liquid dispensing head according to any one of claims 1 to 15, further comprising a pump for circulating liquid.

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