Liquid injection device and filling method

Abstract

To reduce air bubbles remaining in a downstream chamber when filling process is performed to a common liquid chamber having a filter.SOLUTION: A liquid ejecting apparatus includes: multiple nozzles; a common liquid chamber communicating with the nozzles; a filter that partitions the common liquid chamber into an upstream chamber and a downstream chamber; an inlet for introducing the liquid into the upstream chamber; an outlet for leading out the liquid from the upstream chamber; a liquid storage section; a supply passage which allows the inlet and the liquid storage section to communicate with each other; and a recovery passage which allows the inlet and the liquid storage section to communicate with each other. A beam portion connecting a pair of inner walls defining the downstream chamber is provided within the downstream chamber. The liquid ejecting apparatus may perform a compressive discharge operation for compressing the supply passage to discharge the liquid from the nozzles and a circulation operation for circulating the liquid in a circulation path, including the liquid storage section, the supply passage, the common liquid chamber, and the recovery passage, in an order of the liquid storage section, the supply passage, the common liquid chamber, the recovery passage, and the liquid storage section. In filling process for filling the circulation path with the liquid, the circulation operation is performed after the compressive discharge operation.SELECTED DRAWING: Figure 11

Description

[Technical Field]

[0001] The present invention relates to a liquid ejecting apparatus and a filling method. [Background Art]

[0002] Conventionally, liquid ejecting apparatuses that eject a liquid such as ink from a plurality of nozzles have been known. For example, Patent Document 1 discloses a liquid ejecting apparatus comprising: a liquid storage section capable of storing a liquid; a common liquid chamber communicating with the plurality of nozzles; a supply flow path for supplying the liquid from the liquid storage section to the common liquid chamber; and a recovery flow path for recovering the liquid from the common liquid chamber to the liquid storage section. The common liquid chamber of the liquid ejecting apparatus disclosed in Patent Document 1 is partitioned into an upstream chamber and a downstream chamber by a filter. The upstream chamber is provided with an introduction port that communicates with the recovery flow path and is for introducing the liquid into the upstream chamber, and a discharge port that communicates with the recovery flow path and is for discharging the liquid.

[0003] Further, Patent Document 2 discloses a liquid ejecting apparatus comprising: a liquid storage section; a liquid ejecting head having a plurality of nozzles; a supply flow path for supplying the liquid from the liquid storage section to the liquid ejecting head; and a recovery flow path for recovering the liquid from the liquid ejecting head, wherein the liquid is circulated between the liquid storage section and the liquid ejecting head. The liquid ejecting apparatus disclosed in Patent Document 2 has an open-close valve capable of opening and closing the recovery flow path. Furthermore, Patent Document 2 describes that in a filling process of filling the supply flow path, the recovery flow path and the liquid ejecting head with the liquid, after performing a circulation operation of circulating the liquid with the recovery flow path opened by the open-close valve, a pressure discharge operation of closing the recovery flow path by the open-close valve and discharging the liquid from the liquid ejecting head is performed. [Prior Art Documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Unexamined Patent Publication No. 2017-217612 [Patent Document 2] Japanese Unexamined Patent Publication No. 2021-187003 [Summary of the Invention] [Problems that the invention aims to solve]

[0005] In the liquid injection head described in Patent Document 1, it is conceivable to provide a beam portion in the flow path member constituting the downstream chamber, which extends in a direction intersecting the direction in which the liquid flows from the inlet to the outlet within the common liquid chamber. When the liquid injection head described in Patent Document 1 has a beam portion, if the filling process described in Patent Document 2 is performed, air bubbles may accumulate between the filter and the beam portion due to the circulation operation. [Means for solving the problem]

[0006] A liquid injection device according to a preferred embodiment of the present invention comprises: a plurality of nozzles for injecting liquid in the injection direction; a common liquid chamber communicating with the plurality of nozzles and extending in a first direction perpendicular to the injection direction; a filter dividing the common liquid chamber into an upstream chamber and a downstream chamber; an inlet for introducing liquid into the upstream chamber; an outlet for discharging liquid from the upstream chamber; a liquid storage section capable of storing liquid; a supply channel connecting the inlet and the liquid storage section; and a recovery channel connecting the outlet and the liquid storage section, wherein the downstream chamber comprises a pair of inner walls defining the downstream chamber. A beam is provided to connect the nozzles, and the pair of inner walls are spaced apart in a direction intersecting the first direction when viewed in the direction of injection, and it is possible to perform a pressurized discharge operation in which liquid is discharged from the plurality of nozzles by pressurizing the supply channel, and a circulation operation in which liquid is circulated in the order of the liquid storage section, the supply channel, the common liquid chamber, the recovery channel, and the liquid storage section through a circulation path including the liquid storage section, the supply channel, the common liquid chamber, the recovery channel, and the liquid storage section, and the filling process for filling the circulation path with liquid is characterized in that the circulation operation is performed after the pressurized discharge operation is performed.

[0007] A filling method according to a preferred embodiment of the present invention is a filling method for a liquid injection device comprising: a plurality of nozzles for injecting liquid in the injection direction; a common liquid chamber communicating with the plurality of nozzles and extending in a first direction perpendicular to the injection direction; a filter dividing the common liquid chamber into an upstream chamber and a downstream chamber; an inlet for introducing liquid into the upstream chamber; an outlet for discharging liquid from the upstream chamber; a liquid storage section capable of storing liquid; a supply channel connecting the inlet and the liquid storage section; and a recovery channel connecting the outlet and the liquid storage section, wherein the downstream chamber comprises a filter that defines the downstream chamber. A beam is provided connecting a pair of inner walls, and the pair of inner walls are spaced apart in a direction intersecting the first direction when viewed in the direction of injection. The apparatus is capable of performing a pressurized discharge operation in which liquid is discharged from the plurality of nozzles by pressurizing the supply channel, and a circulation operation in which liquid is circulated in the order of the liquid storage section, the supply channel, the common liquid chamber, the recovery channel, and the liquid storage section through a circulation path including the liquid storage section, the supply channel, the common liquid chamber, the recovery channel, and the liquid storage section. The filling process for filling the circulation path with liquid is characterized in that the circulation operation is performed after the pressurized discharge operation. [Brief explanation of the drawing]

[0008] [Figure 1] A schematic diagram illustrating a liquid injection device 100 according to the first embodiment. [Figure 2] A diagram illustrating the circulation mechanism 15 and the on / off valve 16. [Figure 3] A perspective view of the liquid injection head 50 and support body 41 according to the first embodiment. [Figure 4] An exploded perspective view of the liquid injection head 50 according to the first embodiment. [Figure 5] Disassembled perspective view of head tip 54. [Figure 6] Cross-sectional view of line AA in Figure 5. [Figure 7] Cross-sectional view of line BB in Figure 5. [Figure 8] This diagram shows the flow of ink in the common liquid chamber R during circulation operation when the circulation path KJ is not filled with ink. [Figure 9]A diagram illustrating the flow of ink in the common liquid chamber R during a pressure discharge operation performed after a circulation operation. [Figure 10] A flowchart showing the filling process of the present embodiment. [Figure 11] A diagram illustrating the flow of ink in the common liquid chamber R in step S2. [Figure 12] A diagram illustrating the flow of ink in the common liquid chamber R in step S6. [Figure 13] A diagram illustrating the flow of ink in the common liquid chamber R during execution of a pressure discharge operation in a liquid ejecting apparatus 100-A according to a first modification. [Figure 14] A diagram illustrating the flow of ink in the common liquid chamber R during execution of a circulation operation performed after a pressure discharge operation in a liquid ejecting apparatus 100-B according to a second modification. [Figure 15] A diagram illustrating the flow of ink in the common liquid chamber R during execution of a circulation operation performed after a pressure discharge operation in a liquid ejecting apparatus 100-C according to a third modification. [Figure 16] A cross-sectional view taken along line C-C in FIG. 15. [Figure 17] A diagram for explaining a head chip 54-D according to a fourth modification. [Figure 18] A diagram for explaining a head chip 54-D according to the fourth modification. [Figure 19] A diagram for explaining the flow path of a liquid ejecting apparatus 100-E according to a fifth modification. [Figure 20] A diagram for explaining the flow path of a liquid ejecting apparatus 100-F according to a sixth modification. [Figure 21] A diagram for explaining a liquid ejecting apparatus 100-G according to a seventh modification. [Figure 22] A diagram for explaining a liquid ejecting apparatus 100-H according to an eighth modification. DETAILED DESCRIPTION OF THE INVENTION

[0009] 1. First Embodiment Hereinafter, modes for carrying out the present invention will be described with reference to the drawings. However, in each figure, the dimensions and scales of each part are appropriately different from the actual ones. Further, since the embodiments described below are preferred specific examples of the present invention, various technically preferable limitations are attached thereto, but the scope of the present invention is not limited to these modes unless there is a statement specifically limiting the present invention in the following description.

[0010] For convenience, the following description will be made by appropriately using the X-axis, Y-axis, and Z-axis that intersect each other. Further, in the following description, one direction along the X-axis is the X1 direction, and the direction opposite to the X1 direction is the X2 direction. Similarly, the directions opposite to each other along the Y-axis are the Y1 direction and the Y2 direction. Further, the directions opposite to each other along the Z-axis are the Z1 direction and the Z2 direction. In addition, viewing in the Z-axis direction may be simply referred to as "planar view". Note that the Z2 direction is an example of the "ejection direction". The Y1 direction or the Y2 direction is an example of the "first direction". The X1 direction or the X2 direction is an example of the "third direction".

[0011] Here, typically, the Z-axis is a vertical axis, and in the first embodiment, the Z2 direction coincides with the gravity direction GV. In addition, the X-axis, Y-axis, and Z-axis are orthogonal to each other.

[0012] 1-1. Schematic Configuration of Liquid Ejection Apparatus FIG. 1 is a schematic view illustrating the liquid ejection apparatus 100 according to the first embodiment. The liquid ejection apparatus 100 is an inkjet printing apparatus that ejects ink, which is an example of "liquid", as droplets onto a medium PP. For example, the liquid ejection apparatus 100 has a substantially box shape and is placed on a placement surface orthogonal to the gravity direction GV. The medium PP is typically printing paper. Note that the medium PP is not limited to printing paper, and may be a printing target of any material such as a resin film or a fabric, for example.

[0013] As shown in FIG. 1, the liquid ejection apparatus 100 includes a main tank 10, a pump 12, a circulation mechanism 15, an on-off valve 16, a control module 20, a conveyance mechanism 30, a moving mechanism 40, and a liquid ejection head 50.

[0014] The main tank 10 is a container for storing ink. Specific examples of the main tank 10 include a cartridge that can be attached to or detached from the liquid injection device 100, a bag-shaped ink pack made of a flexible film, and an ink tank that can be refilled with ink.

[0015] Although not shown in the diagram, the main tank 10 has multiple containers for storing different types of ink. The inks stored in these multiple containers are not particularly limited, but examples include cyan ink, magenta ink, yellow ink, black ink, clear ink, white ink, and processing liquid, and a combination of two or more of these is used. The composition of the ink is not particularly limited, and may be, for example, an aqueous ink in which a colorant such as a dye or pigment is dissolved in an aqueous solvent, a solvent-based ink in which a colorant is dissolved in an organic solvent, or an ultraviolet-curable ink.

[0016] In this embodiment, a configuration is illustrated in which four different types of ink are used. These four types of ink are, for example, cyan ink, magenta ink, yellow ink, and black ink, which are inks of different colors.

[0017] The control module 20 controls the operation of each element of the liquid injection device 100. For example, the control module 20 includes a processing circuit such as a CPU or FPGA and a storage circuit such as a semiconductor memory. CPU stands for Central Processing Unit. FPGA stands for Field Programmable Gate Array. The control module 20 outputs a drive signal Com and a control signal SI toward the liquid injection head 50. The drive signal Com is a signal that includes a drive pulse that drives the drive element of the liquid injection head 50. The control signal SI is a signal that specifies whether or not to supply the drive signal Com to the drive element.

[0018] The transport mechanism 30, under the control of the control module 20, transports the medium PP in the transport direction DM, which is the Y1 direction. The moving mechanism 40, under the control of the control module 20, reciprocates the liquid injection head 50 in the X1 direction and the X2 direction. In the example shown in Figure 1, the moving mechanism 40 has a roughly box-shaped support 41 called a carriage that houses the liquid injection head 50, and a transport belt 42 to which the support 41 is fixed. In addition to the liquid injection head 50, the main tank 10 described above may also be mounted on the support 41.

[0019] The liquid spray head 50 has multiple head chips 54, as described later, and under the control of the control module 20, it sprays ink supplied from the main tank 10 from each of the multiple nozzles N of each head chip 54 toward the medium PP in the spraying direction Z2. The liquid spraying device 100 performs a printing operation in which a predetermined image is formed on the surface of the medium PP by ink, as this spraying is performed in parallel with the transport of the medium PP by the transport mechanism 30 and the reciprocating movement of the liquid spray head 50 by the moving mechanism 40.

[0020] The liquid spray head 50 is connected to the main tank 10 via a circulation mechanism 15. The circulation mechanism 15, under the control of the control module 20, supplies ink to each of the multiple liquid spray heads 50 and recovers the ink discharged from each of the multiple liquid spray heads 50 for resupply to the liquid spray heads 50. The circulation mechanism 15 and the on-off valve 16 are provided for each of the different types of ink. The circulation mechanism 15 and the on-off valve 16 will be explained with reference to Figure 2.

[0021] 1-2. Circulation mechanism 15 and on / off valve 16 Figure 2 is a diagram illustrating the circulation mechanism 15 and the on / off valve 16. As shown in Figure 2, the circulation mechanism 15 includes a sub-tank 151 and a pump 159. In Figure 2, we will explain one arbitrary type of ink from among several types of ink. In Figure 2, in order to avoid complexity in the drawing, only two head chips 54 supplied with one type of ink are shown out of the multiple head chips 54. Furthermore, in Figure 2, in order to avoid complexity in the drawing, only the interior of one of the two head chips 54 is shown.

[0022] The sub-tank 151 is connected to the supply channel SF1 and the recovery channel CF1, and stores ink for supply to multiple liquid spray heads 50. The sub-tank 151 stores ink for supply to the liquid spray heads 50, ink recovered from the liquid spray heads 50, and ink replenished from the main tank 10. The sub-tank 151 is an example of a "liquid storage section".

[0023] The supply channel SF1 connects the inlet Pin for introducing ink to the head chip 54 to the sub-tank 151. The supply channel SF1 has an internal supply channel SJ1 and an internal head supply channel SH1. The internal supply channel SJ1 is a channel provided outside the liquid spray head 50, connected to the sub-tank 151 and communicating with the head inlet Qin for introducing ink to the liquid spray head 50. The internal head supply channel SH1 is a channel provided inside the liquid spray head 50 and supplies ink to each of the multiple head chips 54. The internal head supply channel SH1 has a main channel connected to the internal supply channel SJ1 and multiple branch channels that branch off from the main channel for each of the multiple head chips 54. In this embodiment, a main tank 10 is provided for each of the four types of ink, and the example shown in Figure 2, in which one type of ink is supplied to two head chips 54, will be described. Furthermore, it is assumed that two types of ink can be supplied to one head chip 54. However, the liquid spray head 50 may supply any one type of ink to three or more head chips 54, or it may supply it to one head chip 54.

[0024] The recovery channel CF1 connects the outlet Pout for discharging ink from the head tip 54 to the sub-tank 151. The recovery channel CF1 has an internal recovery channel CJ1 and an internal head recovery channel CH1. The internal recovery channel CJ1 is a channel provided outside the liquid spray head 50, connected to the sub-tank 151 and communicating with the head outlet Qout for discharging ink from the liquid spray head 50. The internal head recovery channel CH1 is a channel provided inside the liquid spray head 50, and recovers ink from each of the multiple head tips 54. The internal head recovery channel CH1 has a main channel connected to the internal recovery channel CJ1 and multiple branch channels for connecting the main channel to each of the multiple head tips 54.

[0025] The on-off valve 16 is installed in the middle of the internal recovery passage CJ1 of the device. The on-off valve 16 can close and open the internal recovery passage CJ1 of the device under the control of the control module 20. In the following description, closing the internal recovery passage CJ1 of the device by the on-off valve 16 may be described as "closing the on-off valve 16," and opening the internal recovery passage CJ1 of the device by the on-off valve 16 may be described as "opening the on-off valve 16." Note that a device other than the control module 20 may control the on-off valve 16. The on-off valve 16 can be any type of valve that can be controlled by a device such as the control module 20, for example, a diaphragm valve, a solenoid valve, or an electric valve.

[0026] In this embodiment, the on-off valve 16 is located in the middle of the internal recovery channel CJ1, but the on-off valve 16 may also be located in the middle of the main channel portion of the internal head recovery channel CH1, or multiple on-off valves 16 may be located in the middle of each of the multiple branch channels of the internal head recovery channel CH1.

[0027] Pump 159 is installed in the middle of the supply flow path SJ1 within the device. Under the control of the control module 20, pump 159 causes the first ink from the sub-tank 151 to flow to the liquid spray head 50.

[0028] The head tip 54 is provided with a common liquid chamber R that communicates with multiple nozzles N. The common liquid chamber R is divided into an upstream chamber UR and a downstream chamber DR by a filter 54o. As shown in Figure 2, the inlet Pin and outlet Pout are provided in the upstream chamber UR. The multiple nozzles N communicate with the downstream chamber DR. The internal elements of the head tip 54 will be described later with reference to Figures 5, 6, and 7.

[0029] As described above, the liquid injection device 100 has a circulation path KJ which includes a sub-tank 151, a supply channel SF1, a common liquid chamber R, and a recovery channel CF1. Under the direction of the control module 20, the liquid injection device 100 can perform a circulation operation in which ink is circulated through the circulation path KJ in the order of sub-tank 151, supply channel SF1, common liquid chamber R, recovery channel CF1, and sub-tank 151.

[0030] Furthermore, when ink is ejected from nozzle N, the amount of ink in sub-tank 151 decreases. Therefore, the pump 12, under the control of the control module 20, replenishes the ink in sub-tank 151 by supplying ink from the main tank 10 to sub-tank 151 as needed. The timing for replenishing the ink in sub-tank 151 is, for example, when the ink level in sub-tank 151 falls below a predetermined height.

[0031] 1-3. Installation status of liquid spray head 50 Figure 3 is a perspective view of the liquid injection head 50 and support 41 according to the first embodiment. As shown in Figure 3, the liquid injection head 50 is supported by the support 41. The support 41 is a member that supports the liquid injection head 50, and as described above, in this embodiment it is a substantially box-shaped carriage.

[0032] Here, the support body 41 is provided with an opening 41a and a plurality of screw holes 41b. In this embodiment, the support body 41 is substantially box-shaped with a plate-shaped bottom, for example, the bottom is provided with an opening 41a and a plurality of screw holes 41b. The liquid spray head 50 is inserted into the opening 41a and fixed to the support body 41 by screwing it using the plurality of screw holes 41b. As described above, the liquid spray head 50 is attached to the support body 41.

[0033] In the example shown in Figure 3, there is one liquid spray head 50 attached to the support 41. However, there may be two or more liquid spray heads 50 attached to the support 41. In this case, the support 41 is appropriately provided with, for example, a number or shape of openings 41a corresponding to the number of liquid spray heads 50.

[0034] 1-4. Configuration of the liquid injection head Figure 4 is an exploded perspective view of the liquid injection head 50 according to the first embodiment. As shown in Figure 4, the liquid injection head 50 has a flow channel structure 51, a substrate unit 52, a holder 53, four head tips 54_1 to 54_4, a fixing plate 55, and a cover 58. These are arranged in the order of cover 58, substrate unit 52, flow channel structure 51, holder 53, four head tips 54, and fixing plate 55 in the Z2 direction. The parts of the liquid injection head 50 will be described sequentially below.

[0035] The flow channel structure 51 is a structure in which a flow channel is provided inside for supplying the ink stored in the main tank 10 to the four head tips 54. The flow channel structure 51 has a flow channel member 51a and eight connecting pipes 51b.

[0036] The flow channel structure 51 is provided with four in-head supply channels SH1, each for one of the four types of ink, and four in-head recovery channels CH1, each for one of the four types of ink. Each of the four in-head supply channels SH1 has one head inlet Qin that receives ink from the in-device supply channel SJ1, and two outlets that discharge the ink toward the inlet Pin of the head chip 54. Each of the four in-head recovery channels CH1 has two inlets that receive ink from the outlet Pout of the head chip 54, and one head outlet Qout that discharges the ink toward the in-device recovery channel CJ1. Each of the multiple connecting pipes 51b is either a head inlet Qin or a head outlet Qout, and is provided on the surface of the flow channel member 51a facing the Z1 direction. In contrast, the discharge port of the supply channel SH1 within each head and the inlet port of the recovery channel CH1 within each head are provided on the surface of the channel member 51a facing the Z2 direction.

[0037] Furthermore, the flow channel member 51a is provided with a plurality of wiring holes 51c. Each of these wiring holes 51c is a hole through which the wiring board 54i of the head chip 54, described later, passes toward the board unit 52. The side surface of the flow channel member 51a is provided with two notches in the circumferential direction. The flow channel member 51a is also provided with holes (not shown), and is fixed to the holder 53 by screw fastening through these holes.

[0038] The flow channel member 51a, although not shown in the figure, is composed of a laminate formed by stacking multiple substrates in a direction along the Z-axis. Each of the multiple substrates is appropriately provided with grooves and holes for forming the aforementioned in-head supply channel SH1 and in-head recovery channel CH1, and is joined to each other by means of adhesive, welding, or screws, for example.

[0039] Each of the eight connecting pipes 51b is a tubular body protruding from the surface of the flow channel member 51a facing the Z1 direction. The eight connecting pipes 51b correspond to the four in-head supply flow channels SH1 and the four in-head recovery flow channels CH1 mentioned above. These eight connecting pipes 51b are used by connecting them to the aforementioned sub-tank 151 via tubes and the like that which constitute the in-device supply flow channel SJ1 and the in-device recovery flow channel CJ1.

[0040] The substrate unit 52 is an assembly having mounting components for electrically connecting the liquid injection head 50 to the control module 20. The substrate unit 52 includes a circuit board 52a, a connector 52b, and a support plate 52c.

[0041] The circuit board 52a is a printed circuit board such as a rigid wiring board having wiring for electrically connecting each head chip 54 and the connector 52b. The circuit board 52a is placed on the flow channel structure 51 via a support plate 52c, and the connector 52b is installed on the surface of the circuit board 52a facing the Z1 direction.

[0042] The connector 52b is a connecting component for electrically connecting the liquid injection head 50 and the control module 20. The support plate 52c is a plate-shaped member for attaching the circuit board 52a to the flow path structure 51. The circuit board 52a is placed on one side of the support plate 52c, and the circuit board 52a is fixed to the support plate 52c by screws or the like.

[0043] The holder 53 is a structure that houses and supports four head chips 54. The holder 53 is roughly tray-shaped and has a recess 53a, a plurality of wiring holes 53c, a plurality of recesses 53d, a plurality of holes 53e, a plurality of screw holes 53i, and a plurality of screw holes 53k. The recess 53a opens toward the Z1 direction and is the space in which the aforementioned flow channel member 51a is arranged. Each of the plurality of wiring holes 53c is a hole through which the wiring board 54i of the head chip 54 passes toward the board unit 52. Each of the plurality of recesses 53d opens toward the Z2 direction and is the space in which the head chip 54 is arranged. The multiple holes 53e are through holes for connecting each of the multiple inlet pins and outlets Pouts provided by the multiple head chips 54, which will be described later, to the outlet of the in-head supply channel SH1 and the inlet of the in-head recovery channel CH1, which are formed in the flow channel member 51a. The multiple screw holes 53i are screw holes for screwing the holder 53 to the support 41. The multiple screw holes 53k are screw holes for screwing the cover 58 to the holder 53.

[0044] Each head chip 54 ejects ink. Each head chip 54 has a plurality of nozzles N for ejecting a first ink and a plurality of nozzles N for ejecting a second ink of a different type from the first ink. Here, the first ink and the second ink are two of the four types of ink described above. For example, head chips 54_1 and 54_2 each use two of the four types of ink as the first and second inks. Head chips 54_3 and 54_4 each use the remaining two types of ink from the four types. A wiring board 54i is provided on each head chip 54. Note that the configuration of each head chip 54 is simplified in Figure 4. The configuration of the head chip 54 will be described in detail later based on Figure 5.

[0045] The fixing plate 55 is a plate-shaped member to which the four head tips 54 and the holder 53 are fixed. Specifically, the fixing plate 55 is positioned so that the four head tips 54 are sandwiched between it and the holder 53, and each head tip 54 and the holder 53 are fixed with adhesive or the like. The fixing plate 55 is provided with a plurality of openings 55a that expose the nozzle surfaces FN of the four head tips 54. In the example shown in Figure 4, these plurality of openings 55a are provided individually for each head tip 54. The fixing plate 55 is made of a metal material such as stainless steel, titanium, and magnesium alloy.

[0046] The cover 58 is a box-shaped component that houses the substrate unit 52. The cover 58 is provided with eight through holes 58a and an opening 58b. The eight through holes 58a correspond to the eight connecting pipes 51b of the flow channel structure 51, and the corresponding connecting pipe 51b is inserted into each through hole 58a. The aforementioned connector 52b is passed through the opening 58b from the inside to the outside of the cover 58.

[0047] 1-5. Head Tip Configuration Figure 5 is an exploded perspective view of the head chip 54. Figure 6 is a cross-sectional view taken along line AA in Figure 5. Figure 7 is a cross-sectional view taken along line BB in Figure 5. However, to avoid making the diagrams too complex, the wiring board 54i is not shown in Figure 7. As shown in Figures 5 and 6, the head chip 54 has a plurality of nozzles N arranged in the direction along the Y axis. These plurality of nozzles N are divided into a first nozzle row L1 and a second nozzle row L2, which are spaced apart from each other in the direction along the X axis. The first nozzle row L1 and the second nozzle row L2 are sets of a plurality of nozzles N arranged linearly in the direction along the Y axis.

[0048] The head tip 54 has a configuration that is approximately symmetrical with respect to the X-axis. However, the positions of the multiple nozzles N of the first nozzle row L1 and the multiple nozzles N of the second nozzle row L2 along the Y-axis may coincide or differ. Figure 6 illustrates a configuration in which the positions of the multiple nozzles N of the first nozzle row L1 and the multiple nozzles N of the second nozzle row L2 along the Y-axis coincide.

[0049] As shown in Figures 5 and 6, the head chip 54 includes a flow path forming member 54a, a pressure chamber substrate 54b, a nozzle plate 54c, a vibration absorber 54d, a diaphragm 54e, a plurality of piezoelectric elements 54f, a protective substrate 54g, a wiring substrate 54i, a drive circuit 54j, a frame 54k, a case 54n, and a filter 54o. However, to avoid making the diagrams too complex, the pressure chamber substrate 54b, the diaphragm 54e, the plurality of piezoelectric elements 54f, the vibration absorber 54d, the wiring substrate 54i, the drive circuit 54j, and the frame 54k are omitted from Figure 5.

[0050] The flow path forming member 54a and the pressure chamber substrate 54b are stacked in this order in the Z1 direction, forming a flow path for supplying ink to multiple nozzles N. In the region located in the Z1 direction from the flow path forming member 54a, the filter 54o, the pressure chamber substrate 54b, the diaphragm 54e, multiple piezoelectric elements 54f, the protective substrate 54g, the case 54n, the wiring substrate 54i, and the drive circuit 54j are installed. On the other hand, in the region located in the Z2 direction from the flow path forming member 54a, the nozzle plate 54c, the vibration absorber 54d, and the frame 54k are installed. Each element of the head chip 54 is generally a plate-shaped member that is elongated in the Y direction, and is joined to each other, for example, by adhesive. The elements of the head chip 54 will be described in order below.

[0051] The nozzle plate 54c is a plate-shaped member provided with multiple nozzles N in the first nozzle row L1 and the second nozzle row L2, respectively. Each of the multiple nozzles N is a through hole through which ink passes. Here, the surface of the nozzle plate 54c facing the Z2 direction is the nozzle surface FN. In other words, the normal direction of the nozzle surface FN is the direction of the normal vector of the nozzle surface FN, which is the Z2 direction, the spray direction.

[0052] The flow path forming member 54a is provided with a downstream chamber DR, a plurality of connecting flow paths Ra, and a plurality of communicating flow paths Na for each of the first nozzle row L1 and the second nozzle row L2, respectively. Here, the downstream chamber DR that communicates with a plurality of nozzles N of the first nozzle row L1 is referred to as downstream chamber DR[L1]. The downstream chamber DR that communicates with a plurality of nozzles N of the second nozzle row L2 is referred to as downstream chamber DR[L2].

[0053] The downstream chamber DR[L1] includes an opening DR1[L1] that penetrates the flow path forming member 54a in the Z-axis direction, an opening DR2[L1] that penetrates the flow path forming member 54a in the Z-axis direction, and a connecting flow path Xa[L1]. The openings DR1[L1] and DR2[L1] are separated by a beam portion BR[L1] that extends in the X-axis direction. Each of the openings DR1[L1] and DR2[L1] extends in the Y-axis direction. Similarly, the downstream chamber DR[L2] includes an opening DR1[L2] that penetrates the flow path forming member 54a in the Z-axis direction, an opening DR2[L2] that penetrates the flow path forming member 54a in the Z-axis direction, and a connecting flow path Xa[L2]. The openings DR1[L2] and DR2[L2] are separated by a beam portion BR[L2] that extends in the X-axis direction. Openings DR1[L2] and DR2[L2] each extend in the Y-axis direction.

[0054] Here, if there is no particular distinction between openings DR1[L1] and DR1[L2], they are simply referred to as opening DR1. Similarly, if there is no particular distinction between connecting channel Xa[L1] and connecting channel Xa[L2], they are simply referred to as connecting channel Xa. Furthermore, if there is no particular distinction between openings DR2[L1] and opening DR2[L2], they are simply referred to as opening DR2. If there is no particular distinction between beam section BR[L1] and beam section BR[L2], they are simply referred to as beam section BR.

[0055] The beam section BR extends along the X-axis and connects the inner walls wDR of the downstream chamber DR. The inner walls wDR are spaced apart in the direction along the X-axis. However, the direction of extension of the beam section BR is not limited to the X-axis, but can be in a direction that intersects the Y-axis. The beam section BR is part of the flow path forming member 54a. The beam section BR is provided at approximately the center in the direction along the Y-axis. Therefore, in Figure 6, when the cross section of line AA is viewed in the Y2 direction, the beam section BR is actually visible, but it is not shown in order to make the opening DR1 easier to understand. In the example in Figure 5, one beam section BR is provided corresponding to the first nozzle row L1 and the second nozzle row L2, but multiple beam sections BR may be provided corresponding to the first nozzle row L1 and the second nozzle row L2. The direction along the X-axis can also be said to be the direction that intersects the direction along the Y-axis. Note that the direction along the X-axis is an example of a "direction that intersects the first direction".

[0056] The connecting channel Xa communicates with multiple connecting channels Ra at one end in the X-axis direction and with both openings DR1 and DR2 at the other end in the X-axis direction. In other words, ink that has passed through openings DR1 and DR2 flows through connecting channel Xa to the multiple connecting channels Ra. Each of the connecting channels Ra and the communicating channels Na is a through-hole formed for each nozzle N.

[0057] As shown in Figure 6, a common liquid chamber R is provided for each of the first nozzle row L1 and the second nozzle row L2, communicating with multiple nozzles N. The common liquid chamber R extends in a direction along the Y axis, which is perpendicular to the Z2 direction, which is the spray direction. In the following description, the common liquid chamber R communicating with multiple nozzles N of the first nozzle row L1 may be referred to as common liquid chamber R[L1]. The common liquid chamber R communicating with multiple nozzles N of the second nozzle row L2 may be referred to as common liquid chamber R[L2]. The common liquid chamber R stores the ink supplied to the multiple pressure chambers CB. The common liquid chamber R is defined by a vibration absorber 54d, a flow path forming member 54a, a filter 54o, and a case 54n. The filter 54o divides the common liquid chamber R into an upstream chamber UR and a downstream chamber DR. The flow path forming member 54a defines a part of the downstream chamber DR.

[0058] The pressure chamber substrate 54b is a plate-shaped member provided with a plurality of pressure chambers CB for each of the first nozzle row L1 and the second nozzle row L2. The plurality of pressure chambers CB are arranged in the direction along the Y axis. Each pressure chamber CB is formed for each nozzle N and is a long space extending in the direction along the X axis in a plan view. The flow channel forming member 54a and the pressure chamber substrate 54b are manufactured, for example, by processing a silicon single crystal substrate using semiconductor manufacturing technology, similar to the nozzle plate 54c described above. However, other known methods and materials may be used as appropriate for the manufacture of the flow channel forming member 54a and the pressure chamber substrate 54b.

[0059] Furthermore, it is preferable that the channel forming member 54a and the beam portion BR are formed from a single silicon single crystal substrate. However, the channel forming member 54a and the beam portion BR may be manufactured separately, and then the beam portion BR may be welded to the channel forming member 54a.

[0060] The pressure chamber CB is the space located between the flow path forming member 54a and the diaphragm 54e. For each of the first nozzle row L1 and the second nozzle row L2, multiple pressure chambers CB are arranged in a direction along the Y axis. The pressure chamber CB also communicates with the communication flow path Na and the connecting flow path Ra, respectively. Therefore, the pressure chamber CB communicates with the nozzle N via the communication flow path Na and with the downstream chamber DR via the connecting flow path Ra.

[0061] A diaphragm 54e is positioned on the surface of the pressure chamber substrate 54b facing the Z1 direction. The diaphragm 54e is an elastically vibrating plate-shaped member. The diaphragm 54e has, for example, a first layer and a second layer, which are stacked in this order in the Z1 direction. The first layer is, for example, an elastic film composed of silicon oxide. This elastic film is formed, for example, by thermal oxidation of one surface of a silicon single crystal substrate. The second layer is, for example, an insulating film composed of zirconium oxide. This insulating film is formed, for example, by forming a zirconium layer by sputtering and then thermally oxidizing the layer. Note that the diaphragm 54e is not limited to the stacked configuration of the first and second layers described above, and may be composed of, for example, a single layer or three or more layers.

[0062] On the surface of the diaphragm 54e facing the Z1 direction, a plurality of piezoelectric elements 54f, each corresponding to a nozzle N, are arranged as driving elements for the first nozzle row L1 and the second nozzle row L2, respectively. Each piezoelectric element 54f is a passive element that deforms in response to the supply of a driving signal Com. Each piezoelectric element 54f has an elongated shape extending along the X-axis in a plan view. The plurality of piezoelectric elements 54f are arranged along the Y-axis to correspond to the plurality of pressure chambers CB. The piezoelectric elements 54f overlap the pressure chambers CB in a plan view.

[0063] Each piezoelectric element 54f, although not shown, has a first electrode, a piezoelectric layer, and a second electrode, and these are stacked in this order in the Z1 direction. One of the first and second electrodes is an individual electrode that is spaced apart from each other for each piezoelectric element 54f, and a drive signal Com is applied to this electrode. The other electrode is a common strip-shaped electrode that extends along the Y-axis so as to be continuous across the plurality of piezoelectric elements 54f, and a predetermined reference potential is supplied to this other electrode. Examples of metallic materials for these electrodes include platinum, aluminum, nickel, gold, and copper, and one of these can be used alone or two or more can be used in combination in the form of an alloy or stacking. The piezoelectric layer is made of a piezoelectric material such as lead zirconate titanate, and for example, it is a strip-shaped layer that extends along the Y-axis so as to be continuous across the plurality of piezoelectric elements 54f. However, the piezoelectric layer may be a single unit across the plurality of piezoelectric elements 54f. In this case, the piezoelectric layer is provided with through holes extending along the X-axis in regions corresponding to the gaps between adjacent pressure chambers CB in a plan view. When the diaphragm 54e vibrates in conjunction with the deformation of the piezoelectric element 54f, the pressure inside the pressure chamber CB fluctuates, causing ink to be ejected from the nozzle N. Alternatively, instead of the piezoelectric element 54f, a heating element that heats the ink inside the pressure chamber CB may be used as the driving element.

[0064] The protective substrate 54g is a plate-shaped member installed on the surface of the diaphragm 54e facing the Z1 direction, protecting the multiple piezoelectric elements 54f and reinforcing the mechanical strength of the diaphragm 54e. As shown in Figures 5 and 6, the protective substrate 54g is provided with an opening h1. The opening h1 is a hole through which the wiring board 54i passes. In addition, on the surface of the protective substrate 54g facing the Z2 direction, two recesses are formed that are recessed in the Z1 direction, corresponding to the two first nozzle rows L1 and the second nozzle row L2, respectively. The multiple piezoelectric elements 54f are housed between these recesses of the protective substrate 54g and the diaphragm 54e. The protective substrate 54g is made of, for example, a silicon single crystal substrate.

[0065] The filter 54o is a plate-shaped or sheet-shaped member that is laminated on the surface of the flow path forming member 54a facing the Z1 direction. The filter 54o allows the ink to pass through while capturing foreign matter and other contaminants that may be mixed into the ink.

[0066] The filter 54o is provided with a plurality of filter holes h23 through which ink passes, and an opening h21. The opening h21 is a through hole through which the pressure chamber substrate 54b passes. The plurality of filter holes h23 are provided within the filter hole region FR. In the following description, the filter hole region FR provided with filter holes h23 communicating with the downstream chamber DR[L1] is sometimes referred to as filter hole region FR[L1], and the filter hole region FR provided with filter holes h23 communicating with the downstream chamber DR[L2] is sometimes referred to as filter hole h23[L1], and the filter holes h23 provided in the filter hole region FR[L2] are sometimes referred to as filter hole h23[L2]. The filter hole region FR is composed of an electroformed filter. The constituent material of the electroformed filter is, for example, a Ni-Pd alloy. Alternatively, the constituent material of the electroformed filter may be stainless steel.

[0067] Case 54n is a component laminated on the surface of filter 54o facing the Z1 direction. Case 54n defines the upstream chamber UR. Case 54n is provided with an opening h41, an upstream chamber UR communicating with multiple nozzles N of the first nozzle row L1, an upstream chamber UR communicating with multiple nozzles N of the second nozzle row L2, an inlet Pin provided in each of these two upstream chambers UR, and an outlet Pout provided in each of these two upstream chambers UR. The opening h41 is a hole through which the wiring board 54i passes. In the following description, the upstream chamber UR included in the common liquid chamber R[L1] may be referred to as upstream chamber UR[L1], and the upstream chamber UR included in the common liquid chamber R[L2] may be referred to as upstream chamber UR[L2]. The upstream chamber UR is formed by recessing in the Z1 direction from the surface SZ2 of case 54n facing the Z2 direction.

[0068] Case 54n is made of a resin material such as modified polyphenylene ether resin, polyphenylene sulfide resin, or polypropylene resin. Alternatively, case 54n may be made of a metal material.

[0069] The vibration absorber 54d, also called the compliance substrate, is a flexible resin film that forms the wall surface of the common liquid chamber R and absorbs pressure fluctuations of the ink in the common liquid chamber R. The vibration absorber 54d may also be a flexible thin plate made of metal. The surface of the vibration absorber 54d facing the Z1 direction is joined to the flow path forming member 54a with an adhesive or the like. On the other hand, the frame 54k is joined to the surface of the vibration absorber 54d facing the Z2 direction with an adhesive or the like. The frame 54k is a frame-shaped member that runs along the outer circumference of the vibration absorber 54d and contacts the aforementioned fixing plate 55. Here, the frame 54k is made of a metal material such as stainless steel, aluminum, titanium, and magnesium alloy.

[0070] The wiring board 54i is mounted on the surface of the diaphragm 54e facing the Z1 direction and is a mounting component for electrically connecting the control module 20 and the head chip 54. The wiring board 54i is a flexible wiring board such as COF, FPC, or FFC. COF is an abbreviation for Chip On Film. FPC is an abbreviation for Flexible Printed Circuit. FFC is an abbreviation for Flexible Flat Cable. In this embodiment, a drive circuit 54j for supplying a drive voltage to each piezoelectric element 54f is mounted on the wiring board 54i. The drive circuit 54j is a circuit that switches whether or not to supply at least a part of the waveform included in the drive signal Com as a drive pulse based on the control signal SI.

[0071] 1-6. Regarding the beam section BR The rigidity of the channel forming member 54a tends to be lower than that of the case 54n. Specifically, the case 54n has an outer wall in the Z1 direction, which allows it to maintain a certain degree of rigidity, while the channel forming member 54a has a long opening extending in the direction along the Y axis, which reduces its rigidity. When rigidity decreases, the channel forming member 54a may deform due to pressure, for example, when curing adhesive. Therefore, in this embodiment, by providing a beam portion BR in the channel forming member 54a, the decrease in rigidity of the channel forming member 54a can be suppressed.

[0072] The beam section BR is located in the center of the downstream chamber DR in the Y-axis, which further suppresses the decrease in rigidity of the flow path forming member 54a. Specifically, as shown in Figure 7, the beam section BR is located in the central range YDR2 of the ranges YDR1, YDR2, and YDR3 obtained by equally dividing the downstream chamber DR into three ranges on a plane parallel to the XZ plane. Furthermore, although not shown in Figure 7, it is preferable that the beam section BR is located in the central range obtained by equally dividing the downstream chamber DR into five ranges on a plane parallel to the XZ plane.

[0073] It is preferable that the inlet Pin and outlet Pout be located at both ends of the common liquid chamber R in the direction along the Y-axis. For example, if the inlet Pin and outlet Pout are located in the center of the common liquid chamber R in the direction along the Y-axis, ink stagnation will occur at both ends of the common liquid chamber R in the direction along the Y-axis, increasing the likelihood of air bubbles accumulating. Therefore, as can be understood from Figures 5 and 7, the beam section BR is necessarily located between the inlet Pin and outlet Pout when viewed in the direction along the Z-axis. The more specific positions of the beam section BR, inlet Pin, and outlet Pout will be explained using the ranges YR1, YR2, and YR3 obtained by dividing the common liquid chamber R into three equal parts on a plane parallel to the XZ plane. The beam section BR is included in the central range YR2 of ranges YR1, YR2, and YR3. The input pin is located in range YR3, which is the furthest in the Y2 direction from range YR1, range YR2, and range YR3. The output Pout is located in range YR1, which is the furthest in the Y1 direction from range YR1, range YR2, and range YR3.

[0074] As shown in Figure 7, the surface SB1 of the beam BR facing the case 54n is flush with the surface SB2 of the flow path forming member 54a facing the case 54n. Flushness means there is no step between the two surfaces. Therefore, there is no gap between the beam BR and the filter 54o in the direction along the Z axis. The beam BR supports a part of the filter 54o, specifically the part that overlaps with the beam BR when viewed along the Z axis.

[0075] 1-7. Filling process One possible method for filling the circulation path KJ with ink when it is not yet filled is to perform a pressurized discharge operation, in which, after performing a circulation operation, the on / off valve 16 is closed and the supply path SF1 is pressurized by the pump 159 to discharge ink from multiple nozzles N. However, in an embodiment in which the common liquid chamber R has a filter 54o and the flow path forming member 54a has a beam portion BR, the inventors' experiments have shown that in a filling process in which a pressurized discharge operation is performed after a circulation operation, air bubbles may accumulate in the region sandwiched between the filter 54o and the beam portion BR, or at the corner of the beam portion BR, and furthermore, these accumulated air bubbles may combine with other air bubbles and grow into larger bubbles. The region sandwiched between the two members means that one of the two members is in contact with this region in one direction, and the other of the two members is in contact with this region in a direction different from that direction. Figures 8 and 9 illustrate how air bubbles accumulate in the region between the filter 54o and the beam BR, or in the corners of the beam BR.

[0076] Figure 8 shows the flow of ink in the common liquid chamber R during circulation operation when the circulation path KJ is not filled with ink. However, in Figure 8, and in Figures 9, 11, and 12 described later, the common liquid chamber R is shown as a rectangle for easy illustration of the ink flow. Furthermore, in Figures 8, 9, 11, and 12, the size of the arrows indicating the ink flow is increased as the ink flow rate increases, in order to intuitively illustrate the ink flow. Furthermore, in Figures 8, 9, 11, and 12, the area filled with ink is indicated by horizontal dashed lines. Furthermore, in Figures 8, 9, 11, and 12, the outline of the nozzle N is shown with a dashed line to indicate the positional relationship between the common liquid chamber R and the nozzle N. Furthermore, in Figures 8, 9, 11, and 12, the direction of gravity GV is shown. As described above, in the first embodiment, the direction of gravity GV coincides with the Z2 direction. Therefore, the horizontal plane HF and the nozzle surface FN are parallel. Furthermore, in Figures 8, 9, 11, and 12, for ease of understanding, the on-off valve 16 is shown as a white outline when it is open, and as a black filled shape when it is closed. As shown in Figure 8, the on-off valve 16 is open during circulation.

[0077] As shown in Figure 8, the ink introduced from the inlet Pin flows through the upstream chamber UR and is discharged from the outlet Pout. Furthermore, a portion of the ink introduced from the inlet Pin flows into the downstream chamber DR through the filter hole h23 and flows through the downstream chamber DR. Due to the passage through the filter hole h23, the flow rate of the ink in the downstream chamber DR is smaller than the flow rate of the ink in the upstream chamber UR. Furthermore, as shown in Figure 8, the ink flowing through the downstream chamber DR collides with the beam BR and branches into two directions: Z2 and Z1.

[0078] Since ink flows into the circulation path KJ before it is filled with ink, the air that was filling the circulation path KJ forms bubbles in the common liquid chamber R. During the circulation operation, the pressure of the ink flowing through the common liquid chamber R is strongly negative near the outlet Pout, making it difficult for bubbles to accumulate, and bubbles near the outlet Pout are easily discharged from the outlet Pout. On the other hand, the negative pressure is less pronounced between the inlet Pin and the outlet Pout compared to the area near the outlet Pout, resulting in a decrease in ink flow rate. Furthermore, as mentioned above, the ink flow rate in the downstream chamber DR is smaller than the ink flow rate in the upstream chamber UR. Therefore, the bubbles in the downstream chamber DR are less affected by the ink flow due to the circulation operation and the effect of buoyancy becomes relatively larger, causing them to move in the Y1 direction as well as in the Z1 direction, which is opposite to the direction of gravity GV. As a result, bubbles located in the Y2 direction from the beam BR in the downstream chamber DR tend to accumulate and grow in the area sandwiched between the filter 54o and the beam BR, or at the corners of the beam BR. Figure 8 shows the bubbles BL that are located in the Y2 direction relative to the beam BR and have accumulated and grown in the region sandwiched between the filter 54o and the beam BR. The position in the Y2 direction relative to the beam BR can also be described as the position closest to the inlet Pin among the two directions along the Y axis relative to the beam BR.

[0079] Figure 9 shows the flow of ink in the common liquid chamber R during pressurized discharge operation after circulation operation. During pressurized discharge operation, the on-off valve 16 is closed and the supply channel SF1 is pressurized to discharge ink from multiple nozzles N. Therefore, as shown in Figure 9, the on-off valve 16 is closed during pressurized discharge operation. During pressurized discharge operation, since the only ink outlets are the nozzles N, the ink is discharged from the nozzles N. As shown in Figure 9, droplets DP are discharged from each of the multiple nozzles N. As shown in Figure 9, the flow of ink in the upstream chamber UR reaches the downstream chamber DR via the filter holes h23 of the filter 54o. As shown in Figure 9, the direction of the ink flow in the downstream chamber DR is generally parallel to the Z2 direction. The amount of flow generated by the pressurized discharge operation is offset by the buoyancy acting on the air bubbles BL, and the air bubbles BL tend to remain in the region sandwiched between the filter 54o and the beam BR, or at the corners of the beam BR.

[0080] If printing is performed while air bubbles BL remain, a large negative pressure will act on the common liquid chamber R when a large amount of ink is consumed, such as during solid ink printing. This can draw the air bubbles BL from the common liquid chamber R to the nozzle N, potentially causing a misfire.

[0081] Therefore, in the filling process in this embodiment, the liquid injection device 100 performs a circulation operation after performing a pressurized discharge operation.

[0082] 1-8. Filling process of the first embodiment Figure 10 is a flowchart showing the filling process of this embodiment. In step S2, the liquid injection device 100 closes the on / off valve 16 and performs a pressurized discharge operation while the circulation path KJ is not filled with ink.

[0083] Figure 11 shows the flow of ink in the common liquid chamber R during step S2. Since ink flows into the circulation path KJ before it is filled with ink, the air that was filling the circulation path KJ forms bubbles and is generated in the downstream chamber DR. However, in Figure 11, since there is no ink flow from the inlet Pin to the outlet Pout, the bubbles do not accumulate in the area sandwiched between the filter 54o and the beam BR or at the corners of the beam BR. Therefore, the bubbles generated in the downstream chamber DR do not combine with other bubbles, making it easier for them to pass through the filter holes h23 and move to the upstream chamber UR. Also, since the bubbles in the downstream chamber DR are relatively small, they can be easily discharged from the nozzles N by the pressurized discharge operation, carried by the ink flow from the inlet Pin to the multiple nozzles N.

[0084] After step S2 is completed, the liquid injection device 100 opens the on-off valve 16 in step S4 and performs a circulation operation in step S6.

[0085] Figure 12 shows the flow of ink in the common liquid chamber R in step S6. By performing the circulation operation with air bubbles removed from the downstream chamber DR, as shown in Figure 12, ink does not accumulate in the area between the filter 54o and the beam BR, or in the corners of the beam BR. Furthermore, when the on / off valve 16 is opened, ink is also filled into the recovery channel CF1.

[0086] After step S6 is completed, the liquid injection device 100 completes the series of processes shown in Figure 10.

[0087] 1-9. Summary of the First Embodiment As described above, the liquid injection device 100 according to the first embodiment includes a plurality of nozzles N that inject ink in the Z2 direction, which is the injection direction; a common liquid chamber R that communicates with the plurality of nozzles N and extends in a direction along the Y axis perpendicular to the Z2 direction; a filter 54o that divides the common liquid chamber R into an upstream chamber UR and a downstream chamber DR; an inlet Pin for introducing ink into the upstream chamber UR; an outlet Pout for discharging ink from the upstream chamber UR; a sub-tank 151 capable of storing ink; a supply channel SF1 that connects the inlet Pin and the sub-tank 151; and a recovery channel CF1 that connects the outlet Pout and the sub-tank 151. The downstream chamber DR is equipped with a beam section BR that connects a pair of inner walls wDR that are spaced apart when viewed along the Z-axis and along the X-axis, and define the downstream chamber DR. The system is capable of performing a pressurized discharge operation in which ink is discharged from multiple nozzles N by pressurizing the supply channel SF1, and a circulation operation in which ink is circulated in the following order through the circulation path KJ, which includes the sub-tank 151, the supply channel SF1, the common liquid chamber R, the recovery channel CF1, and the sub-tank 151. The filling process for filling the circulation path KJ with ink is performed after the pressurized discharge operation. By performing the pressurized discharge operation before the circulation operation, no ink flow occurs from the inlet Pin to the outlet Pout before the pressurized discharge operation, making it difficult for bubbles to grow. Consequently, bubbles in the downstream chamber DR are more easily discharged. In other words, the liquid injection device 100 according to the first embodiment performs the circulation operation after discharging bubbles in the downstream chamber DR, which, compared to an embodiment in which the pressurized discharge operation is performed after the circulation operation, can suppress the accumulation of bubbles in the region sandwiched between the beam BR and the filter 54o due to the circulation operation, and can reduce the risk of bubbles remaining in the downstream chamber DR after the circulation operation.

[0088] Furthermore, the system is further equipped with an on-off valve 16 that can open and close the recovery channel CF1 according to the first embodiment. The pressurized discharge operation is performed with the recovery channel CF1 closed by the on-off valve 16, and the circulation operation is performed with the recovery channel CF1 open by the on-off valve 16.

[0089] Furthermore, the liquid injection device 100 according to the first embodiment includes a flow path forming member 54a that defines a part of the downstream chamber DR and supports the filter 54o, the beam portion BR is part of the flow path forming member 54a and a part of the filter 54o is supported by the beam portion BR. Compared to an embodiment without the beam BR, the liquid injection device 100 according to the first embodiment can suppress the deflection of the filter 54o in the Z2 direction. Therefore, the liquid injection device 100 according to the first embodiment can stably support the filter 54o by suppressing its deflection, and can also suppress the accumulation of bubbles in the downstream chamber DR by performing a pressurized discharge operation before the circulation operation.

[0090] Furthermore, the beam section BR is positioned between the inlet Pin and the outlet Pout when viewed along the Z-axis. As described above, it is preferable that the inlet Pin and outlet Pout be provided at both ends of the common liquid chamber R in the direction along the Y axis. Therefore, in this embodiment, the beam BR is positioned between the inlet Pin and outlet Pout when viewed in the direction along the Z axis, which suppresses ink stagnation at both ends of the common liquid chamber R in the direction along the Y axis compared to an embodiment where the beam BR is not located between the inlet Pin and outlet Pout. Furthermore, when positioned between the inlet Pin and outlet Pout when viewed in the direction along the Z axis, if a circulation operation is performed before a pressurized discharge operation, bubbles will accumulate in the area sandwiched between the filter 54o and the beam BR, or at the corners of the beam BR. However, in this embodiment, by performing a pressurized discharge operation before a circulation operation, it is possible to suppress the accumulation of bubbles in the downstream chamber DR.

[0091] 2. Variations Each of the forms exemplified above can be modified in various ways. Specific examples of modifications are given below. Two or more forms arbitrarily selected from the following examples can be merged as appropriate, provided they do not contradict each other.

[0092] 2-1. First variation In the first embodiment, the Z2 direction coincided with the gravity direction GV, but this is not limited to the first embodiment.

[0093] Figure 13 shows the flow of ink in the common liquid chamber R during pressurized discharge operation in the liquid injection device 100-A according to the first modification. The liquid injection device 100-A differs from the liquid injection device 100 according to the first embodiment in that the Y2 direction coincides with the gravity direction GV. Therefore, in the first modification, the nozzle surface FN is inclined at 90 degrees with respect to the horizontal plane HF. In other words, the common liquid chamber R according to the first modification can be said to be used in a state in which the common liquid chamber R according to the first embodiment is rotated 90 degrees counterclockwise when viewed from the X1 direction to the X2 direction with the X axis as the central axis.

[0094] If the pressurized discharge operation is performed after the circulation operation, the circulation operation causes ink to flow from the inlet Pin to the outlet Pout before the pressurized discharge operation, which may cause bubbles to accumulate in region AR shown in Figure 13. Region AR is located in the Y2 direction of the beam BR and is the region sandwiched between the filter 54o and the beam BR. On the other hand, the liquid injection device 100-A according to the first modified example performs the pressurized discharge operation before the circulation operation, so that ink does not flow from the inlet Pin to the outlet Pout due to the circulation operation, and thus the accumulation of bubbles in region AR can be suppressed.

[0095] Furthermore, in the first modified example, a configuration in which the liquid injection device 100-A is used with the X-axis as the central axis and the common liquid chamber R rotated 90 degrees counterclockwise when viewed from the X1 direction to the X2 direction, is shown. However, the configuration in which the liquid injection device 100 is used is not limited to the first modified example. For example, even in a configuration in which the liquid injection device 100 is used with the X-axis as the central axis and the common liquid chamber R rotated counterclockwise by a range greater than 0 degrees and less than 90 degrees when viewed from the X1 direction to the X2 direction, the risk of air bubbles remaining in the common liquid chamber R after the circulation operation can be reduced compared to a configuration in which a pressurized discharge operation is performed after a circulation operation.

[0096] 2-2. Second variation In the first embodiment, the distances from the horizontal plane HF to the inlet Pin and outlet Pout are the same, and in the first modified example, the distance from the horizontal plane HF to the inlet Pin is shorter than the distance from the horizontal plane HF to the outlet Pout. However, the manner in which the liquid injection device 100 is used is not limited to the first embodiment and the first modified example. For example, even in a manner in which the liquid injection device 100 is used when the distance from the horizontal plane HF to the inlet Pin is longer than the distance from the horizontal plane HF to the outlet Pout, the risk of air bubbles remaining in the common liquid chamber R after the circulation operation can be reduced compared to a manner in which a pressurized discharge operation is performed after the circulation operation.

[0097] Figure 14 shows the flow of ink in the common liquid chamber R during the circulation operation performed after the pressurized discharge operation in the liquid injection device 100-B according to the second modified example. The liquid injection device 100-B differs from the liquid injection device 100 according to the first embodiment in that the V1 direction, which is perpendicular to the X axis and obtained by rotating the Z2 direction by 15 degrees counterclockwise when viewed from the X1 direction to the X2 direction, coincides with the gravity direction GV. Figure 14 shows an embodiment in which the liquid injection device 100-B is used with the X axis as the central axis and the common liquid chamber R rotated by 15 degrees clockwise when viewed from the X1 direction to the X2 direction.

[0098] In the second modified example, in the configuration where a pressurized discharge operation is performed after a circulation operation, the force moving the bubbles in the Y1 direction due to the circulation operation may be greater than the force moving the bubbles in the Y2 direction due to buoyancy. However, even in the configuration using the liquid injection device 100-B according to the second modified example, the risk of bubbles remaining in the common liquid chamber R after the circulation operation can be reduced compared to the configuration in which a pressurized discharge operation is performed after a circulation operation.

[0099] Furthermore, in the second modified example, a configuration in which the liquid injection device 100-B is used with the X-axis as the central axis and the common liquid chamber R rotated 15 degrees clockwise when viewed from the X1 direction to the X2 direction, is shown. However, the configuration in which the liquid injection device 100 is used is not limited to the second modified example. For example, even in a configuration in which the liquid injection device 100 is used with the X-axis as the central axis and the common liquid chamber R rotated by an angle greater than 0 degrees and less than 15 degrees clockwise when viewed from the X1 direction to the X2 direction, the risk of air bubbles remaining in the common liquid chamber R after the circulation operation can be reduced compared to a configuration in which a pressurized discharge operation is performed after the circulation operation.

[0100] 2-3. Third Variation In the first and second modified examples, the liquid injection device 100 was used with the common liquid chamber R rotated around the X-axis as the central axis; however, the modes of use of the liquid injection device 100 are not limited to these. For example, even in a mode in which the liquid injection device 100 is used with the common liquid chamber R rotated around the Y-axis as the central axis, the risk of air bubbles remaining in the common liquid chamber R after the circulation operation can be reduced compared to a mode in which a pressurized discharge operation is performed after the circulation operation.

[0101] Figure 15 shows the flow of ink in the common liquid chamber R during the circulation operation performed after the pressurized discharge operation in the liquid injection device 100-C according to the third modified example. Figure 16 is a cross-sectional view taken along line CC in Figure 15. However, in Figure 15, only the X2 direction of the wiring board 54i is shown in the cross-section of the head tip 54 according to the third modified example, which is cut by a plane parallel to the XZ plane and passing through the beam BR. The liquid injection device 100-C differs from the liquid injection device 100 according to the first embodiment in that the X1 direction coincides with the gravity direction GV. Figures 15 and 16 show a mode in which the liquid injection device 100-C is used with the Y axis as the central axis and the common liquid chamber R rotated 90 degrees clockwise when viewed from the Y2 direction to the Y1 direction. In addition, in Figure 16, the head tip 54 is shown in a simplified manner, the nozzle plate 54c and vibration absorber 54d are omitted, and the area near the downstream chamber DR[L1] is shown. Furthermore, in Figure 16, the positional relationship between the downstream chamber DR[L1], the inlet Pin[L1], and the outlet Pout[L1] is shown by the dashed-dotted line connecting the inlet Pin[L1] and the outlet Pout[L1].

[0102] If the pressurized discharge operation is performed after the circulation operation, the circulation operation causes ink to flow from the inlet Pin to the outlet Pout before the pressurized discharge operation, which may cause bubbles to accumulate in region AR-C shown in Figure 16. Region AR-C is located in the Y2 direction with respect to the beam BR[L1] and is the region sandwiched between the inner wall wDR in the X2 direction of the opening DR1[L1] and the beam BR[L1]. On the other hand, the liquid injection device 100-C according to the third modified example performs the pressurized discharge operation before the circulation operation, so that ink does not flow from the inlet Pin to the outlet Pout due to the circulation operation, and thus the accumulation of bubbles in region AR-C can be suppressed.

[0103] Furthermore, in the third modification, a configuration in which the liquid injection device 100-C is used with the Y-axis as the central axis and the common liquid chamber R rotated 90 degrees clockwise when viewed from the Y2 direction to the Y1 direction, is shown. However, the configuration in which the liquid injection device 100 is used is not limited to the third modification. For example, even in a configuration in which the liquid injection device 100 is used with the Y-axis as the central axis and the common liquid chamber R rotated clockwise by an angle greater than 0 degrees and less than 90 degrees when viewed from the Y2 direction to the Y1 direction, the risk of air bubbles remaining in the common liquid chamber R after the circulation operation can be reduced compared to a configuration in which a pressurized discharge operation is performed after the circulation operation. Moreover, even in a configuration in which the liquid injection device 100 is used with the Y-axis as the central axis and the common liquid chamber R rotated counterclockwise by an angle greater than 0 degrees and less than or equal to 90 degrees when viewed from the Y2 direction to the Y1 direction, the risk of air bubbles remaining in the common liquid chamber R after the circulation operation can be reduced compared to a configuration in which a pressurized discharge operation is performed after the circulation operation.

[0104] 2-4. Fourth Variation In each of the above embodiments, the filter 54o and the beam BR were arranged without any gap in the direction along the Z axis, but they may be arranged with a gap between them.

[0105] Figures 17 and 18 are diagrams illustrating the head chip 54-D in the fourth modified example. Figure 17 shows a cross-section of the head chip 54-D when cut along the BB line in Figure 5. Figure 18 shows only the elements located in the X2 direction relative to the wiring board 54i in the cross-section of the head chip 54-D when cut along the BB line in Figure 5.

[0106] The head tip 54-D differs from the head tip 54 in that it has a flow path forming member 54a-D instead of the flow path forming member 54a. The flow path forming member 54a-D differs from the flow path forming member 54a in that it is provided with a beam portion BR-D instead of the beam portion BR. As shown in Figures 17 and 18, the surface SB1-D of the beam portion BR-D facing the case 54n is located in the Z2 direction more than the surface SB2 of the flow path forming member 54a facing the case 54n. Therefore, a gap GP is formed between the filter 54o and the beam portion BR-D in the direction along the Z axis.

[0107] As shown in Figures 17 and 18, the dimension CZ of the gap GP along the Z-axis is shorter than the distance DZ between the beam BR-D and the bottom surface of the downstream chamber DR. Also, as shown in Figure 18, the dimension CZ is shorter than the dimension BX of the beam BR-D along the X-axis. Furthermore, the dimension CZ is shorter than the dimension BZ of the beam BR-D along the Z-axis, and the dimension BY of the beam BR-D along the Y-axis.

[0108] In the liquid injection device 100 according to the fourth modified example, the filter 54o and the beam portion BR-D are arranged with a gap GP in the direction along the Z axis, and the dimension CZ of the gap GP in the direction along the Z axis is shorter than the distance DZ between the beam portion BR-D and the bottom surface of the downstream chamber DR. As dimension CZ increases, the distance from the filter 54o in the direction along the Z axis increases, making it difficult to stably support the filter 54o. However, in the liquid injection device 100 according to the fourth modification, the gap GP is formed such that dimension CZ is shorter than distance DZ, so the filter 54o can be stably supported compared to the embodiment in which dimension CZ is longer than distance DZ. However, because dimension CZ is shorter than distance DZ, it becomes difficult for bubbles in the downstream chamber DR to pass through the gap GP and move from the inlet Pin to the outlet Pout. However, in the fourth modification as well, a circulation operation is performed after the pressurized discharge operation, so it is possible to suppress the accumulation and growth of bubbles on the inlet Pin side of the beam BR-D that cannot pass through the gap GP, and thus suppress the accumulation of bubbles in the downstream chamber DR, similar to the first embodiment.

[0109] Furthermore, dimension CZ is shorter than dimension BX in the direction along the X-axis of beam section BR-D. As described above, the liquid injection device 100 according to the fourth modification can stably support the filter 54o compared to the embodiment in which dimension CZ is longer than dimension BX. Furthermore, since a circulation operation is performed after the pressurized discharge operation, the accumulation of air bubbles in the downstream chamber DR can be suppressed.

[0110] Furthermore, dimension CZ is shorter than dimension BZ, which is along the Z-axis of beam section BR-D, and dimension BY, which is along the Y-axis of beam section BR-D. When dimensions BZ and BY are shortened, the rigidity of the beam section BR-D decreases, and consequently, the rigidity of the flow path forming member 54a-D decreases. Therefore, the liquid injection device 100 according to the fourth modified example can suppress the decrease in rigidity of the flow path forming member 54a-D compared to the configuration in which dimension CZ is longer than dimension BZ, and the configuration in which dimension CZ is longer than dimension BY. In addition, since a circulation operation is performed after the pressurized discharge operation, the accumulation of air bubbles in the downstream chamber DR can be suppressed.

[0111] 2-5. Fifth Variation The liquid injection device 100 in each of the above embodiments may further have a bypass channel BP connecting the supply channel SF1 and the recovery channel CF1.

[0112] Figure 19 is a diagram illustrating the flow path of the liquid injection device 100-E in the fifth modified example. The liquid injection device 100-E differs from the liquid injection device 100 according to the first embodiment in that it has a bypass flow path BP connecting the supply flow path SF1 and the recovery flow path CF1. In the example of Figure 19, the bypass flow path BP is a flow path provided outside the liquid injection head 50. One end Rin of the bypass flow path BP is provided between the pump 159 of the internal supply flow path SJ1 and the head inlet Qin in the supply flow path SF1. However, the bypass flow path BP may be provided inside the liquid injection head 50, and may also be provided for each head tip 54.

[0113] The other end Rout of the bypass channel BP is located between the on-off valve 16 of the in-device recovery channel CJ1 and the head outlet Qout, within the recovery channel CF1.

[0114] Figure 19 shows the ink flow during pressurized discharge operation. During pressurized discharge operation, the on-off valve 16 is closed. As shown in Figure 19, the pressurization by the pump 159 generates flows FR1 and FR2. Flow FR1 is the flow of ink in the order of supply channel SF1, common liquid chamber R, and nozzle N. Flow FR2 is the flow of ink in the order of bypass channel BP, the channel of the recovery channel CF1 from the other end Rout to the outlet Pout, the common liquid chamber R, and nozzle N. Note that the channel of the recovery channel CF1 from the other end Rout to the outlet Pout is an example of "part of the recovery channel".

[0115] In the liquid injection device 100-E according to the fifth modified example, the pressurized discharge operation pressurizes the supply channel SF1 and the recovery channel CF1, generating a flow FR1 in which ink flows in the order of supply channel SF1, common liquid chamber R, and multiple nozzles N, and a flow FR2 in which ink flows in the order of a part of the recovery channel CF1, common liquid chamber R, and multiple nozzles N. The liquid injection device 100-E according to the fifth modification can reduce the amount of bubbles remaining in the common liquid chamber R compared to the first embodiment, in which only the flow FR1 is discharged from the common liquid chamber R during the pressurized discharge operation. Specifically, in the first embodiment, only the inlet Pin is pressurized and the outlet Pout is not, but in the fifth modification, both the inlet Pin and the outlet Pout are pressurized. Therefore, compared to the liquid injection device 100 according to the first embodiment, the liquid injection device 100-E according to the fifth modification can apply a larger pressure to the nozzle N that is closer to the outlet Pout than to the inlet Pin among the multiple nozzles N, thus enabling more bubbles to be discharged from the nozzle N.

[0116] 2-6. Sixth Variation In each of the above embodiments, except for the fifth modified example, the liquid injection device 100 may have a pump instead of the on-off valve 16 in the internal recovery channel CJ1.

[0117] Figure 20 is a diagram illustrating the flow path of the liquid injection device 100-F according to the sixth modified example. The liquid injection device 100-F differs from the liquid injection device 100 according to the first embodiment in that it has a pump 158 instead of an on-off valve 16. The pump 158 is capable of applying positive and negative pressure to the outlet Pout.

[0118] In the example shown in Figure 20, the pump 158 is included in the circulation mechanism 15. During the circulation operation, the pump 158 generates negative pressure relative to the outlet Pout, allowing the ink to circulate faster compared to the liquid injection device 100 according to the first embodiment.

[0119] Furthermore, the pressurized discharge operation, which is performed before the circulation operation, pressurizes the supply channel SF1 by pump 159 and the recovery channel CF1 by pump 158, thereby generating flow FR1 in which ink flows in the order of supply channel SF1, common liquid chamber R, and multiple nozzles N, and flow FR2-F in which ink flows in the order of recovery channel CF1, common liquid chamber R, and multiple nozzles N.

[0120] As described above, the liquid injection device 100-F according to the sixth modification, like the liquid injection device 100-E according to the fifth modification, can reduce the amount of bubbles remaining in the common liquid chamber R compared to a configuration in which only the flow FR1 is discharged from the common liquid chamber R during pressurized discharge operation.

[0121] 2-7. Seventh Variation The common liquid chamber R in each of the above embodiments is provided with one inlet Pin and one outlet Pout, but is not limited to this.

[0122] Figure 21 is a diagram illustrating a liquid injection device 100-G according to the seventh modified example. The liquid injection device 100-G differs from the liquid injection device 100 according to the first embodiment in that it has a case 54n-G instead of case 54n, and a head tip 54 having a flow path forming member 54a-G instead of flow path forming member 54a. A common liquid chamber RG is formed by case 54n-G and flow path forming member 54a-G. The common liquid chamber RG differs from the common liquid chamber R in that it has an upstream chamber UR-G instead of upstream chamber UR, and a downstream chamber DR-G instead of downstream chamber DR.

[0123] Case 54n-G differs from case 54n in that it has inlet Pin-G1 and inlet Pin-G2 instead of inlet Pin, and outlet Pout-G instead of outlet Pout. Hereinafter, inlet Pin-G1 and inlet Pin-G2 may be collectively referred to as inlet Pin-G. As shown in Figure 21, inlet Pin-G1 is provided at the Y1 end of the upstream chamber UR-G. Inlet Pin-G2 is provided at the Y2 end of the upstream chamber UR-G. Outlet Pout-G is provided between inlet Pin-G1 and inlet Pin-G2, and more specifically, near the center of the upstream chamber UR-G.

[0124] As shown in Figure 21, the inlet Pin-G1 is connected to the in-head supply channel SH1-G1, and the inlet Pin-G2 is connected to the in-head supply channel SH1-G2. The in-head supply channels SH1-G1 and SH1-G2 are channels within the liquid injection head 50 according to the seventh modified example, and are channels provided in place of the in-head supply channel SH1. The in-head supply channels SH1-G1 and SH1-G2 are each connected to the main flow portion connected to the head inlet Qin. The outlet Pout-G is connected to the in-head recovery channel CH1.

[0125] The flow path forming member 54a-G differs from the flow path forming member 54a in that it is provided with beam sections BR-G1 and BR-G2 instead of beam section BR. As can be seen from Figure 21, beam section BR-G1 is provided between the inlet Pin-G1 and the outlet Pout-G when viewed along the Z-axis. Beam section BR-G2 is provided between the inlet Pin-G2 and the outlet Pout-G when viewed along the Z-axis.

[0126] Figure 21 shows the ink flow during the circulation operation after the pressurized discharge operation in the seventh modified example. As shown in Figure 21, the ink supplied from the inlets Pin-G located at both ends along the Y-axis of the upstream chamber UR-G is discharged from the outlet Pout-G located in the center of the upstream chamber UR-G. Furthermore, the ink supplied from the inlet Pin-G that flows into the downstream chamber DR-G via the filter 54o is also discharged from the center of the downstream chamber DR-G through the upstream chamber UR-G to the outlet Pout-G.

[0127] If the pressurized discharge operation is performed after the circulation operation, the circulation operation will cause ink to flow from each inlet Pin-G to the outlet Pout-G before the pressurized discharge operation, which may cause bubbles to accumulate in regions AR-G1 and AR-G2 shown in Figure 21. Region AR-G1 is located in the Y1 direction with respect to the beam BR-G1 and is the region sandwiched between the beam BR-G1 and the filter 54o. Region AR-G2 is located in the Y2 direction with respect to the beam BR-G2 and is the region sandwiched between the beam BR-G2 and the filter 54o. On the other hand, the liquid injection device 100-G according to the seventh modified example performs the pressurized discharge operation before the circulation operation, so that ink does not flow from the inlet Pin-G1 and inlet Pin-G2 to the outlet Pout-G due to the circulation operation, and thus the accumulation of bubbles in regions AR-G1 and AR-G2 can be suppressed.

[0128] 2-8. Variation 8 In the seventh modification, two inlets Pin are provided for one common liquid chamber R, and one outlet Pout is provided for one common liquid chamber R, but this is not limited to this configuration.

[0129] Figure 22 is a diagram illustrating the liquid injection device 100-H according to the eighth modification. The liquid injection device 100-H differs from the liquid injection device 100-G in that it is provided with one inlet Pin-H for the common liquid chamber RH according to the eighth modification, and outlets Pout-H1 and Pout-H2 are provided. Hereinafter, outlets Pout-H1 and Pout-H2 may be collectively referred to as outlets Pout-H. The shape of the head tip 54 according to the eighth modification is the same as the shape of the head tip 54 according to the seventh modification. In the eighth modification, the common liquid chamber RH is formed by the case 54n-G and the flow path forming member 54a-G. The common liquid chamber RH differs from the common liquid chamber RG in that it has an upstream chamber UR-H instead of an upstream chamber UR-G.

[0130] In upstream chamber UR-H, the opening that functioned as inlet Pin-G1 in upstream chamber UR-G functions as outlet Pout-H1, the opening that functioned as inlet Pin-G2 in upstream chamber UR-G functions as outlet Pout-H2, and the opening that functioned as outlet Pout-G in upstream chamber UR-G functions as inlet Pin-H.

[0131] As shown in Figure 22, outlet Pout-H1 is connected to the in-head recovery channel CH1-H1, and outlet Pout-H2 is connected to the in-head recovery channel CH1-H2. The in-head recovery channels CH1-H1 and CH1-H2 are channels within the liquid injection head 50 according to the eighth modified example, and are channels provided in place of the in-head recovery channel CH1. The in-head recovery channels CH1-H1 and CH1-H2 are each connected to the main flow portion connected to the head outlet Qout. Inlet Pin-H is connected to the in-head supply channel SH1.

[0132] Figure 22 shows the ink flow during the circulation operation after the pressurized discharge operation in the eighth modified example. As shown in Figure 22, the ink supplied from the inlet Pin-H located in the center along the Y-axis of the upstream chamber UR-G is discharged from outlets Pout-H located at both ends along the Y-axis of the upstream chamber UR-H. Furthermore, the ink supplied from the inlet Pin-H that flows into the downstream chamber DR-G via the filter 54o is also discharged from outlets Pout-H through the upstream chamber UR-H from both ends of the downstream chamber DR-G.

[0133] If the pressurized discharge operation is performed after the circulation operation, the circulation operation causes ink to flow from the inlet Pin-H to the respective outlets Pout-H before the pressurized discharge operation, which may cause bubbles to accumulate in regions AR-H1 and AR-H2 shown in Figure 22. Region AR-H1 is located in the Y2 direction with respect to the beam BR-G1 and is sandwiched between the beam BR-G1 and the filter 54o. Region AR-H2 is located in the Y1 direction with respect to the beam BR-G2 and is sandwiched between the beam BR-G2 and the filter 54o. On the other hand, the liquid injection device 100-H according to the eighth modified example performs the pressurized discharge operation before the circulation operation, so that ink does not flow from the inlet Pin-H to the outlet Pout-H1 or outlet Pout-H2 due to the circulation operation, and thus the accumulation of bubbles in regions AR-H1 and AR-H2 can be suppressed.

[0134] 2-9. Variation 9 In the embodiments described above, a serial-type liquid injection device 100 in which the liquid injection head 50 is reciprocated in a direction along the X axis was illustrated, but the present invention is not limited to such embodiments. The liquid injection device may also be a line-type liquid injection device in which a plurality of nozzles N are distributed over the entire width of the medium PP.

[0135] 2-10. Tenth variation In the first embodiment described above, the circulation mechanism 15 included one sub-tank 151, but the present invention is not limited to this embodiment. The circulation mechanism 15 of the liquid injection device 100 may include, instead of the sub-tank 151, a supply-side tank connected to a supply channel SF1 and storing ink for supply to the liquid injection head 50, a recovery-side tank connected to a recovery channel SC1 and storing ink recovered from the liquid injection head 50, a pressurizing section for pressurizing the supply-side tank, a depressurizing section for depressurizing the recovery-side tank, an intermediate channel connecting the supply-side tank and the recovery-side tank, and an intermediate pump provided in the middle of the intermediate channel for moving ink from the recovery-side tank to the supply-side tank via the intermediate channel. The pressurizing section is, for example, a compressor. The depressurizing section is, for example, a vacuum pump. In this type of circulation mechanism 15, by driving the pressurizing unit to create positive pressure in the supply tank, by driving the depressurizing unit to create negative pressure in the recovery tank, and by driving the relay pump, it is possible to circulate the ink in the order of supply tank, supply channel SF1, head tip 54, recovery channel SC1, recovery tank, relay channel, and supply tank. In this configuration, instead of the pump 159, the pressurizing unit may be used to pressurize the supply channel SF1 to perform a pressurized discharge operation. In this modified example, the supply tank and the recovery tank are examples of "liquid storage units".

[0136] 2-11. Other variations The liquid spraying apparatus described above can be used in various devices, including not only equipment dedicated to printing, but also facsimile machines and photocopiers. However, the applications of the liquid spraying apparatus of the present invention are not limited to printing. For example, a liquid spraying apparatus that sprays a solution of colorants can be used as a manufacturing apparatus for forming color filters for liquid crystal display devices. Furthermore, a liquid spraying apparatus that sprays a solution of conductive materials can be used as a manufacturing apparatus for forming wiring and electrodes on wiring boards.

[0137] 3. Addendum From the forms exemplified above, the following configuration can be understood, for example.

[0138] A liquid injection device according to Embodiment 1, which is a preferred embodiment, comprises: a plurality of nozzles for injecting liquid in the injection direction; a common liquid chamber communicating with the plurality of nozzles and extending in a first direction perpendicular to the injection direction; a filter dividing the common liquid chamber into an upstream chamber and a downstream chamber; an inlet for introducing liquid into the upstream chamber; an outlet for discharging liquid from the upstream chamber; a liquid storage section capable of storing liquid; a supply channel connecting the inlet and the liquid storage section; and a recovery channel connecting the outlet and the liquid storage section, wherein the downstream chamber comprises a channel defining the downstream chamber. A beam is provided to connect a pair of inner walls, and the pair of inner walls are spaced apart in a direction intersecting the first direction when viewed in the direction of injection, and it is possible to perform a pressurized discharge operation in which liquid is discharged from the plurality of nozzles by pressurizing the supply channel, and a circulation operation in which liquid is circulated in the order of the liquid storage section, the supply channel, the common liquid chamber, the recovery channel, and the liquid storage section through a circulation path including the liquid storage section, the supply channel, the common liquid chamber, the recovery channel, and the liquid storage section, and the filling process for filling the circulation path with liquid is performed after the pressurized discharge operation is performed. The liquid injection device according to Embodiment 1 performs a circulation operation after discharging bubbles from the downstream chamber. Compared to an embodiment in which a pressurized discharge operation is performed after the circulation operation, this embodiment can suppress the accumulation of bubbles in the area sandwiched between the beam and the filter due to the circulation operation, thereby reducing the risk of bubbles remaining in the downstream chamber after the circulation operation.

[0139] In Embodiment 2, which is a specific example of Embodiment 1, the device further includes an on-off valve capable of opening and closing the recovery passage, wherein the pressurized discharge operation is performed with the recovery passage closed by the on-off valve, and the circulation operation is performed with the recovery passage open by the on-off valve.

[0140] In Embodiment 3, which is a specific example of Embodiment 1, the pressurized discharge operation pressurizes the supply channel and the recovery channel to generate a first flow in which liquid flows in the order of the supply channel, the common liquid chamber, and the plurality of nozzles, and a second flow in which liquid flows in the order of part or all of the recovery channel, the common liquid chamber, and the plurality of nozzles. The liquid injection device according to Embodiment 3 can reduce the amount of bubbles remaining in the common liquid chamber compared to the liquid injection device according to Embodiment 1, in which only the first flow discharges bubbles in the common liquid chamber during the pressurized discharge operation.

[0141] In Embodiment 4, which is a specific example of Embodiment 1, a flow path forming member is provided that defines a part of the downstream chamber and supports the filter, the beam is part of the flow path forming member, and a part of the filter is supported by the beam. The liquid injection device according to embodiment 4 can stably support the filter by suppressing its bending, and can also suppress the accumulation of air bubbles in the downstream chamber by performing a pressurized discharge operation before the circulation operation.

[0142] In Embodiment 5, which is a specific example of Embodiment 1, the filter and the beam are arranged with a gap between them in the injection direction, and the dimension of the gap in the injection direction is shorter than the distance between the beam and the bottom surface of the downstream chamber. The liquid injection device according to embodiment 5 can stably support the filter by suppressing its bending, and can also suppress the accumulation of air bubbles in the downstream chamber by performing a pressurized discharge operation before the circulation operation.

[0143] In embodiment 6, which is a specific example of embodiment 5, the dimension of the gap in the injection direction is shorter than the dimension of the beam in a second direction that is perpendicular to both the injection direction and the first direction. Compared to the embodiment where the dimension of the gap in the injection direction is longer than the dimension of the beam in the second direction, the liquid injection device according to embodiment 6 can suppress a decrease in the rigidity of the flow path forming member, and by performing a pressurized discharge operation before the circulation operation, it can suppress the accumulation of air bubbles in the downstream chamber.

[0144] In embodiment 7, which is a specific example of embodiment 5, the dimension of the gap in the injection direction is shorter than the dimension of the beam portion in the injection direction and the dimension of the beam portion in the first direction, respectively. Compared to the embodiment in which the dimension of the gap in the injection direction is longer than dimension BZ, and the embodiment in which the dimension of the beam in the injection direction is longer than the dimension of the beam in the first direction, the liquid injection device according to embodiment 7 can suppress the reduction in rigidity of the flow path forming member, while suppressing the accumulation of bubbles in the downstream chamber by performing a pressurized discharge operation before the circulation operation.

[0145] In embodiment 8, which is a specific example of embodiment 1, the beam portion is positioned between the inlet and the outlet when viewed in the injection direction.

[0146] A filling method according to preferred embodiment 9 is a filling method for a liquid injection device comprising: a plurality of nozzles for injecting liquid in the injection direction; a common liquid chamber communicating with the plurality of nozzles and extending in a first direction perpendicular to the injection direction; a filter dividing the common liquid chamber into an upstream chamber and a downstream chamber; an inlet for introducing liquid into the upstream chamber; an outlet for discharging liquid from the upstream chamber; a liquid storage section capable of storing liquid; a supply channel connecting the inlet and the liquid storage section; and a recovery channel connecting the outlet and the liquid storage section, wherein the downstream chamber contains the downstream A beam is provided connecting a pair of inner walls that define a chamber, and the pair of inner walls are spaced apart in a direction intersecting the first direction when viewed in the direction of injection, and it is possible to perform a pressurized discharge operation in which liquid is discharged from the plurality of nozzles by pressurizing the supply channel, and a circulation operation in which liquid is circulated in the order of the liquid storage section, the supply channel, the common liquid chamber, the recovery channel, and the liquid storage section through a circulation path including the liquid storage section, the supply channel, the common liquid chamber, the recovery channel, and the liquid storage section, and the filling process for filling the circulation path with liquid is performed after the pressurized discharge operation is performed. According to embodiment 9, the same effects as in embodiment 1 can be obtained.

[0147] In embodiment 10, which is a specific example of embodiment 9, the recovery passage is further equipped with an on-off valve that can open and close it, the pressurized discharge operation is performed with the recovery passage closed by the on-off valve, and the circulation operation is performed with the recovery passage open by the on-off valve.

[0148] In embodiment 11, which is a specific example of embodiment 9, the pressurized discharge operation pressurizes the supply channel and the recovery channel to generate a first flow in which liquid flows in the order of the supply channel, the common liquid chamber, and the plurality of nozzles, and a second flow in which liquid flows in the order of part or all of the recovery channel, the common liquid chamber, and the plurality of nozzles. According to embodiment 11, the same effects as in embodiment 3 can be obtained.

[0149] In embodiment 12, which is a specific example of embodiment 9, a flow path forming member is provided that defines a part of the downstream chamber and supports the filter, the beam is part of the flow path forming member, and a part of the filter is supported by the beam. According to embodiment 12, the same effects as in embodiment 4 can be obtained.

[0150] In embodiment 13, which is a specific example of embodiment 9, the filter and the beam are arranged with a gap between them in the injection direction, and the dimension of the gap in the injection direction is shorter than the distance between the beam and the bottom surface of the downstream chamber. According to embodiment 13, the same effects as in embodiment 5 can be obtained.

[0151] In embodiment 14, which is a specific example of embodiment 13, the dimension of the gap in the injection direction is shorter than the dimension of the beam portion in a second direction that is perpendicular to both the injection direction and the first direction. According to embodiment 14, the same effects as in embodiment 6 can be obtained.

[0152] In embodiment 15, which is a specific example of embodiment 13, the dimension of the gap in the injection direction is shorter than the dimension of the beam portion in the injection direction and the dimension of the beam portion in the first direction, respectively. According to embodiment 15, the same effects as in embodiment 7 can be obtained.

[0153] In embodiment 16, which is a specific example of embodiment 9, the beam portion is positioned between the inlet and the outlet when viewed in the injection direction. [Explanation of symbols]

[0154] 10...Main tank, 12...Pump, 15...Circulation mechanism, 16...On / off valve, 20...Control module, 30...Transport mechanism, 40...Moving mechanism, 41...Support, 41a...Opening, 41b...Screw hole, 42...Transport belt, 50...Liquid injection head, 51...Flow path structure, 51a...Flow path member, 51b...Connecting pipe, 51c...Wiring hole, 52...Substrate unit, 52a...Circuit board, 52b...Connector, 52c...Support plate, 53...Holder, 53a...Recess, 53c...Wiring hole, 53d...Recess, 53e...Hole, 53i, 53k...Screw hole, 54, 54-D...Head tip, 54...Head tip, 54a 54a-D, 54a-G…Flow path forming member, 54b…Pressure chamber substrate, 54c…Nozzle plate, 54d…Vibration absorber, 54e…Vibrating plate, 54f…Piezoelectric element, 54g…Protective substrate, 54i…Wiring board, 54j…Drive circuit, 54k…Frame, 54n, 54n-G…Case, 54o…Filter, 55…Fixing plate, 55a…Opening, 58…Cover, 58a…Through hole, 58b…Opening, 100, 100-A, 100-B, 100-C, 100-E, 100-F, 100-G, 100-H…Liquid injection device, 151…Sub-tank, 158, 159…Pump, AR, AR-C, AR-G1 AR-G2,AR-H1,AR-H2…region, BL…bubble, BP…bypass channel, BR,BR-D,BR-G1,BR-G2…beam section, BX,BY,BZ…dimensions, CB…pressure chamber, CF1…recovery channel, CH1…in-head recovery channel, CH1…recovery channel, CH1-H1,CH1-H2…in-head recovery channel, CJ1…in-device recovery channel, CZ…dimensions, Com…drive signal, DM…conveying direction, DP…droplet, DR,DR-G…downstream chamber, DR1,DR2…opening, DZ…distance, FN…nozzle surface, FR…filter hole region, GP…gap, GV…gravity direction, HF…horizontal plane, KJ… Circulation path, L1...First nozzle row, L2...Second nozzle row, N...Nozzle, Na...Communication channel, PP...Media, Pin, Pin-G, Pin-G1, Pin-G2, Pin-H...Inlet, Pout, Pout-G, Pout-H, Pout-H1, Pout-H2...Outlet, Qin...Head inlet, Qout...Head outlet, R, RG, RH...Common liquid chamber, Ra...Connecting channel, SB1, SB1-D, SB2...Surface, SF1...Supply channel, SH1, SH1-G1, SH1-G2...In-head supply channel, SI...Control signal, SJ1...In-device supply channel, SZ2...Surface, UR, UR-G,UR-H…Upstream chamber, Xa…Connecting channel, YDR1, YDR2, YDR3, YR1, YR2, YR3…Range, h1, h21…Opening, h23…Filter hole, h41…Opening, wDR…Inner wall.

Claims

1. Multiple nozzles that spray liquid in the direction of injection, A common liquid chamber that communicates with the plurality of nozzles and extends in a first direction perpendicular to the injection direction, A filter that divides the aforementioned common liquid chamber into an upstream chamber and a downstream chamber, The upstream chamber has an inlet for introducing liquid, An outlet for discharging liquid from the upstream chamber, A liquid storage section capable of storing liquid, A supply channel connecting the inlet and the liquid storage section, A recovery channel connecting the outlet and the liquid storage section, A flow path forming member that defines a portion of the downstream chamber and supports the filter, Equipped with, Within the downstream chamber, a beam is provided that connects a pair of inner walls that define the downstream chamber. The pair of inner walls are spaced apart in a direction that intersects the first direction when viewed in the direction of injection, The beam portion is part of the flow path forming member, A portion of the filter is supported by the beam, Of the downstream chamber, the portion located on one side of the beam in the first direction and the portion located on the other side of the beam in the first direction are in communication with each other via the space between the beam and the bottom surface of the downstream chamber. A pressurized discharge operation is performed to discharge liquid from the plurality of nozzles by pressurizing the supply channel, The circulation path, which includes the liquid storage section, the supply channel, the common liquid chamber, and the recovery channel, is capable of performing a circulation operation in which the liquid is circulated in the order of the liquid storage section, the supply channel, the common liquid chamber, the recovery channel, and the liquid storage section. The filling process for filling the circulation path with liquid is performed by executing the circulation operation after executing the pressurized discharge operation. A liquid injection device characterized by the following features.

2. The recovery channel is further provided with an on / off valve that can open and close it. The aforementioned pressurized discharge operation is performed with the recovery passage closed by the on / off valve. The aforementioned circulation operation is performed with the recovery passage open by the on / off valve. The liquid injection device according to feature 1.

3. The pressurized discharge operation generates a first flow in which liquid flows in the order of the supply channel, the common liquid chamber, and the plurality of nozzles, and a second flow in which liquid flows in the order of part or all of the recovery channel, the common liquid chamber, and the plurality of nozzles, by pressurizing the supply channel and the recovery channel. The liquid injection device according to feature 1.

4. The beam portion is positioned between the inlet and the outlet when viewed in the direction of injection. The liquid injection device according to feature 1.

5. A plurality of nozzles for spraying liquid in the spraying direction, A common liquid chamber that communicates with the plurality of nozzles and extends in a first direction perpendicular to the injection direction, A filter that divides the aforementioned common liquid chamber into an upstream chamber and a downstream chamber, The upstream chamber has an inlet for introducing liquid, An outlet for discharging liquid from the upstream chamber, A liquid storage section capable of storing liquid, A supply channel connecting the inlet and the liquid storage section, A recovery channel connecting the outlet and the liquid storage section, Equipped with, Within the downstream chamber, a beam is provided that connects a pair of inner walls that define the downstream chamber. The pair of inner walls are spaced apart in a direction that intersects the first direction when viewed in the direction of injection, The filter and the beam are arranged with a gap between them in the injection direction. The dimension of the gap in the injection direction is shorter than the distance between the beam and the bottom surface of the downstream chamber. A pressurized discharge operation is performed to discharge liquid from the plurality of nozzles by pressurizing the supply channel, The circulation path, which includes the liquid storage section, the supply channel, the common liquid chamber, and the recovery channel, is capable of performing a circulation operation in which the liquid is circulated in the order of the liquid storage section, the supply channel, the common liquid chamber, the recovery channel, and the liquid storage section. The filling process for filling the circulation path with liquid is performed by executing the circulation operation after executing the pressurized discharge operation. A liquid injection device characterized by the following features.

6. The dimension of the gap in the injection direction is shorter than the dimension of the beam in a second direction perpendicular to both the injection direction and the first direction. The liquid injection device according to feature 5.

7. The dimensions of the gap in the injection direction are shorter than the dimensions of the beam in the injection direction and the dimensions of the beam in the first direction, respectively. The liquid injection device according to feature 5.

8. Multiple nozzles that spray liquid in the direction of injection, A common liquid chamber that communicates with the plurality of nozzles and extends in a first direction perpendicular to the injection direction, A filter that divides the aforementioned common liquid chamber into an upstream chamber and a downstream chamber, The upstream chamber has an inlet for introducing liquid, An outlet for discharging liquid from the upstream chamber, A liquid storage section capable of storing liquid, A supply channel connecting the inlet and the liquid storage section, A recovery channel connecting the outlet and the liquid storage section, A flow path forming member that defines a portion of the downstream chamber and supports the filter, A method for filling a liquid injection device, comprising: Within the downstream chamber, a beam is provided that connects a pair of inner walls that define the downstream chamber. The pair of inner walls are spaced apart in a direction that intersects the first direction when viewed in the direction of injection, The beam portion is part of the flow path forming member, A portion of the filter is supported by the beam, Of the downstream chamber, the portion located on one side of the beam in the first direction and the portion located on the other side of the beam in the first direction are in communication with each other via the space between the beam and the bottom surface of the downstream chamber. A pressurized discharge operation is performed to discharge liquid from the plurality of nozzles by pressurizing the supply channel, The circulation path, which includes the liquid storage section, the supply channel, the common liquid chamber, and the recovery channel, is capable of performing a circulation operation in which the liquid is circulated in the order of the liquid storage section, the supply channel, the common liquid chamber, the recovery channel, and the liquid storage section. The filling process for filling the circulation path with liquid is performed by executing the circulation operation after executing the pressurized discharge operation. A filling method characterized by the following:

9. The recovery channel is further provided with an on / off valve that can open and close it. The aforementioned pressurized discharge operation is performed with the recovery passage closed by the on / off valve. The aforementioned circulation operation is performed with the recovery passage open by the on / off valve. The filling method according to feature 8.

10. The pressurized discharge operation generates a first flow in which liquid flows in the order of the supply channel, the common liquid chamber, and the plurality of nozzles, and a second flow in which liquid flows in the order of part or all of the recovery channel, the common liquid chamber, and the plurality of nozzles, by pressurizing the supply channel and the recovery channel. The filling method according to feature 8.

11. The beam portion is positioned between the inlet and the outlet when viewed in the direction of injection. The filling method according to feature 8.

12. A plurality of nozzles for spraying liquid in the spraying direction, A common liquid chamber that communicates with the plurality of nozzles and extends in a first direction perpendicular to the injection direction, A filter that divides the aforementioned common liquid chamber into an upstream chamber and a downstream chamber, The upstream chamber has an inlet for introducing liquid, An outlet for discharging liquid from the upstream chamber, A liquid storage section capable of storing liquid, A supply channel connecting the inlet and the liquid storage section, A recovery channel connecting the outlet and the liquid storage section, A method for filling a liquid injection device, comprising: Within the downstream chamber, a beam is provided that connects a pair of inner walls that define the downstream chamber. The pair of inner walls are spaced apart in a direction that intersects the first direction when viewed in the direction of injection, The filter and the beam are arranged with a gap between them in the injection direction. The dimension of the gap in the injection direction is shorter than the distance between the beam and the bottom surface of the downstream chamber. A pressurized discharge operation is performed to discharge liquid from the plurality of nozzles by pressurizing the supply channel, The circulation path, which includes the liquid storage section, the supply channel, the common liquid chamber, and the recovery channel, is capable of performing a circulation operation in which the liquid is circulated in the order of the liquid storage section, the supply channel, the common liquid chamber, the recovery channel, and the liquid storage section. The filling process for filling the circulation path with liquid is performed by executing the circulation operation after executing the pressurized discharge operation. A filling method characterized by the following:

13. The dimension of the gap in the injection direction is shorter than the dimension of the beam in a second direction perpendicular to both the injection direction and the first direction. The filling method according to feature 12.

14. The dimensions of the gap in the injection direction are shorter than the dimensions of the beam in the injection direction and the dimensions of the beam in the first direction, respectively. The filling method according to feature 12.

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