Liquid ejection head

Abstract

The present invention relates to a liquid ejection head having: an ejection module including a pressure chamber and an ejection element configured to eject a liquid in the pressure chamber; a supply passage; a collection passage connected to the supply passage through the pressure chamber; a first pressure regulating unit; a second pressure regulating unit; and a circulation pump. A controlled pressure in the first pressure regulating unit is set to be higher than a controlled pressure in the second pressure regulating unit. A pressure receiving area of a second flexible member and a second press plate in a second pressure control chamber in a case where a second opening is in an open state is smaller than a pressure receiving area of a first flexible member and a first press plate in a first pressure control chamber in a case where a first opening is in an open state.

Description

Technical Field

[0001] This disclosure relates to a liquid injection head. Background Technology

[0002] There exists a liquid jetting device that circulates ink / liquid in a liquid jet head for purposes such as venting air bubbles in the channel or preventing the liquid near the jet nozzle from thickening. In this circulating liquid jetting device, the liquid circulates between the liquid jet head and a liquid storage unit. Ink in the liquid storage unit is supplied to the liquid jet head, and ink in the liquid jet head is collected in the liquid storage unit.

[0003] Japanese Patent Application Publication No. 2019-64254 (hereinafter referred to as Document 1) discloses a structure that performs circulation by generating a pressure difference inside a liquid injection head using a circulating pump and two pressure control mechanisms. Each pressure control mechanism is a so-called pressure-reducing controller mechanism and includes a valve, a pressure plate, a spring, and a flexible diaphragm. The pressure plate is configured to be displaced by being biased by the spring and is connected to the flexible diaphragm. Moreover, the pressure plate is displaced by internal pressure to open and close the valve. In this way, the pressure in the channel can be controlled at a constant pressure.

[0004] In the circulation configuration using a circulating pump and two pressure control mechanisms as described in Reference 1, immediately after the circulating pump stops after printing, the two pressure control mechanisms still maintain a pressure difference. Therefore, the circulation does not stop. Subsequently, during the circulation, ink flows from the pressure control mechanism at the higher pressure to the pressure control mechanism at the lower pressure, causing the pressure in the lower pressure control mechanism to gradually increase until it reaches the same pressure as the higher pressure. As a result, the circulation stops.

[0005] If operations such as wiping or suction recovery are performed while the printing cycle is still running, inks of other colors may enter the nozzle. In this case, these other colors of ink may be carried into the liquid storage unit through the cycle, resulting in color mixing. Therefore, when performing wiring operations, recovery operations, etc., after printing is finished, setting a certain waiting time after the cycle stops to perform the wiring or recovery operations can suppress color mixing. From a production volume point of view, such a waiting time is preferably short. Summary of the Invention

[0006] According to one aspect of this disclosure, a liquid jet head includes: a jet module comprising a pressure chamber and a jetting element configured to generate pressure for jetting liquid in the pressure chamber; a supply channel connected to the pressure chamber, through which liquid is supplied to the pressure chamber; a collection channel connected to the pressure chamber, through which liquid is collected from the pressure chamber; a first pressure regulating unit having a first pressure control chamber connected to the supply channel, a first valve chamber connected to the first pressure control chamber through a first opening, and a first valve configured to open and close the first opening; a second pressure regulating unit having a second pressure control chamber connected to the collection channel, a second valve chamber connected to the second pressure control chamber through a second opening, and a second valve configured to open and close the second opening; and a circulation pump configured to deliver liquid. The first pressure control chamber has a first flexible member disposed on a surface opposite to the first opening, a first pressing plate configured to shift in conjunction with the first flexible member, and a first biasing member configured to bias the first pressing plate in a direction that increases the volume of the first pressure control chamber. The first pressure control chamber is configured to open and close a first opening using a first valve based on the displacement of a first pressing plate and a first flexible member. The second pressure control chamber has a second flexible member disposed on a surface opposite to the second opening, a second pressing plate configured to shift in conjunction with the second flexible member, and a second biasing member configured to bias the second pressing plate in a direction that increases the volume of the second pressure control chamber. The second pressure control chamber is configured to open and close a second opening using a second valve based on the displacement of the second pressing plate and the second flexible member. The controlled pressure in the first pressure regulating unit is set to be higher than the controlled pressure in the second pressure regulating unit. When the second opening is open via the second valve, the pressure receiving area of ​​the second flexible member and the second pressing plate in the second pressure control chamber is smaller than the pressure receiving area of ​​the first flexible member and the first pressing plate in the first pressure control chamber when the first opening is open via the first valve.

[0007] Further features of this disclosure will become apparent from the following description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0008] Figure 1A and 1B These are perspective views and block diagrams showing a liquid jetting device;

[0009] Figure 2 This is an exploded perspective view of the liquid injection head;

[0010] Figure 3A and 3B These are vertical cross-sectional views of the liquid injection head and enlarged cross-sectional views of the injection module;

[0011] Figure 4This is a schematic external view of the loop unit;

[0012] Figure 5 This is a vertical sectional view showing the loop path;

[0013] Figure 6 It is a schematic diagram illustrating the loop path;

[0014] Figures 7A to 7C This is a cross-sectional view showing an example of a pressure regulating unit;

[0015] Figures 8A to 8E It is a diagram depicting the flow of ink inside a liquid jet nozzle;

[0016] Figure 9A and 9B This is a diagram describing the structure of the second pressure regulating unit;

[0017] Figure 10A and 10B This is a diagram describing the structure of the second pressure regulating unit;

[0018] Figures 11A to 11D This is a diagram describing the pressure regulating unit;

[0019] Figure 12A and 12B This is a diagram showing another example of a pressure control unit;

[0020] Figure 13 It is a schematic diagram illustrating the loop path;

[0021] Figure 14 It is a schematic diagram illustrating the loop path;

[0022] Figure 15 It is a schematic diagram illustrating the loop path;

[0023] Figure 16 It is a schematic diagram illustrating the loop path;

[0024] Figure 17A and 17B This is a schematic diagram showing the loop path for one ink color;

[0025] Figure 18 This is a view showing the opening plate;

[0026] Figure 19 This is a view showing the substrate of the spraying element;

[0027] Figures 20A to 20C It is a cross-sectional view showing the ink flow;

[0028] Figure 21A and 21B This is a cross-sectional view showing the area near the injection nozzle;

[0029] Figure 22A and 22B This is a view showing the channel structure of the liquid injection head;

[0030] Figure 23 It is a schematic structural diagram showing the arrangement of circulating pumps, etc. in more detail;

[0031] Figure 24A and 24B This is an external perspective view of the circulating pump; and

[0032] Figure 25 This is a cross-sectional view of a circulating pump. Detailed Implementation

[0033] Embodiments of this disclosure will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the scope of this disclosure, and not all combinations of features described in these embodiments are necessary for the solutions provided in this disclosure. Note that the same constituent elements are denoted by the same reference numerals. This embodiment will be described using a thermal jetting element that generates bubbles by utilizing an electrothermal conversion element to jet liquid as an example of each jetting element, but is not limited to this example. This embodiment can also be applied to liquid jetting heads employing jetting methods using piezoelectric elements and liquid jetting heads employing other jetting methods. Furthermore, the pumps, pressure regulating units, etc., described below are not limited to the constructions described in the embodiments and shown in the drawings.

[0034] <Liquid jetting equipment>

[0035] Figure 1A This is a view used to describe a liquid jetting device, and is an enlarged view of the liquid jetting head and its surroundings. First, refer to... Figure 1A and 1B A schematic construction of the liquid jetting device 50 in this embodiment is described. Figure 1A This is a perspective view schematically showing a liquid jetting device using a liquid jetting head 1. The liquid jetting device 50 in this embodiment is configured as a serial inkjet printing device, which performs printing on a printing medium P by jetting ink as a liquid while scanning the liquid jetting head 1.

[0036] The liquid ejector head 1 is mounted on a carriage 60. The carriage 60 reciprocates along a guide shaft 51 in the main scanning direction (X direction). The printing medium P is conveyed via transport rollers 55, 56, 57, and 58 in a secondary scanning direction (Y direction) that intersects (in this example, perpendicularly intersects) the main scanning direction. Note that in the figures referenced below, the Z direction represents the vertical direction and intersects (in this example, perpendicularly intersects) the XY plane defined by the X and Y directions. The liquid ejector head 1 is configured to be attachable to and detachable from the carriage 60 by a user.

[0037] Liquid injection head 1 includes circulation unit 54 and injection unit 3, which will be described later (see below). Figure 3A and Figure 3B Although the specific construction will be described later, the injection unit 3 includes a plurality of injection ports and an energy generating element (hereinafter referred to as the "injection element") that generates injection energy for ejecting liquid from each injection port.

[0038] The liquid jetting device 50 also includes an ink tank 2 as an ink supply source and an external pump 21. The ink stored in the ink tank 2 is supplied to the circulation unit 54 via the ink supply pipe 59 by the driving force of the external pump 21.

[0039] The liquid jetting apparatus 50 forms a predetermined image on a printing medium P by repeatedly performing print scanning and transport operations. The print scanning includes printing by jetting ink while moving the liquid jetting head 1 mounted on a carriage 60 in the main scanning direction. The transport operation includes transporting the printing medium P in the secondary scanning direction. Note that the liquid jetting head 1 in this embodiment is capable of jetting four types of ink: black (B), cyan (C), magenta (M), and yellow (Y), and using these inks to print full-color images. However, the ink that can be jetted from the liquid jetting head 1 is not limited to the four types mentioned above. This disclosure can also be applied to liquid jetting heads used for jetting other types of ink. In short, the type and quantity of ink jetted from the liquid jetting head are not limited.

[0040] Furthermore, in the liquid jetting apparatus 50, a cover member (not shown) capable of covering the surface of the nozzle of the liquid jetting head 1, where the nozzle is formed, is provided at a position separate from the transport path of the printing medium P in the X direction. During non-printing operations, the cover member covers the surface of the nozzle of the liquid jetting head 1 and serves to prevent the nozzle from drying out, protect the nozzle, and facilitate ink extraction operations from the nozzle.

[0041] Notice, Figure 1AThe liquid ejector head 1 shown represents an example of including four circulation units 54 corresponding to four types of ink, but it is sufficient as long as the included circulation units 54 correspond to the type of liquid to be ejected. Furthermore, multiple circulation units 54 may be included for the same type of liquid. In summary, the liquid ejector head 1 can have a configuration including one or more circulation units. The liquid ejector head 1 can be configured to circulate only at least one of the four types of ink, rather than circulating all four types.

[0042] Figure 1B This is a block diagram showing the control system of the liquid jetting device 50. The CPU 103 acts as a control unit that controls the operation of each unit of the liquid jetting device 50 based on a program (e.g., a processing procedure) stored in the ROM 101. The RAM 102 serves as a working area for the CPU 103 to perform processing, etc. The CPU 103 receives image data from a host device 400 external to the liquid jetting device 50 and controls the head driver 1A to control the driving of the jetting elements installed in the jetting unit 3. The CPU 103 also controls drivers for various actuators installed in the liquid jetting device. For example, the CPU 103 controls a motor driver 105A for the carriage motor 105 used to move the carriage 60, a motor driver 104A for the transfer motor 104 used to transfer the printing medium P, etc. Furthermore, the CPU 103 controls a pump driver 500A for the circulation pump 500 described later, a pump driver 21A for the external pump 21, etc. Note that... Figure 1B The diagram illustrates a configuration for receiving image data from host device 400 and performing processing, but the liquid jetting device 50 can perform processing regardless of whether the data is provided by host device 400.

[0043] <Basic Structure of Liquid Jet Heads>

[0044] Figure 2 These are exploded perspective and top views of the liquid injection head 1 in this embodiment. Figure 3A and 3B yes Figure 2 The liquid jet head 1 shown is a cross-sectional view along line IIIA-IIIA. Figure 3A This is a vertical cross-sectional view of the entire liquid injection head 1. Figure 3B yes Figure 3A The enlarged view of the injection module is shown. The following will primarily refer to... Figures 2 to 3B And refer to as appropriate Figure 1A The basic structure of the liquid injection head 1 in this embodiment will be described below.

[0045] like Figure 2As shown, the liquid ejection head 1 includes a circulation unit 54 and an ejection unit 3 for ejecting ink supplied from the circulation unit 54 onto the recording medium P. In this embodiment, the liquid ejection head 1 is fixedly supported on the carriage 60 of the liquid ejection device 50 by a positioning unit and electrical contacts (not shown) provided on the carriage 60. The liquid ejection head 1 moves along the carriage 60... Figure 1A Printing is performed on the recording medium P while the main scanning direction (X direction) is moved.

[0046] The external pump 21 connected to the ink tank 2, which serves as the ink supply source, includes an ink supply tube 59 (see [link]). Figure 1A A liquid connector (not shown) is provided at the end of each of these ink supply tubes 59. With the liquid ejector head 1 mounted on the liquid ejector device 50, the liquid connector, located at the end of the ink supply tube 59 and serving as the inlet through which the liquid is introduced, is sealed to the liquid connector insertion slot 53a provided on the head housing 53 of the liquid ejector head 1. As a result, an ink supply path is formed extending from the ink tank 2 to the liquid ejector head 1 via the external pump 21. In this embodiment, four types of ink are used. Therefore, four sets of components are provided for each ink, each set including the ink tank 2, the external pump 21, the ink supply tube 59, and the circulation unit 54, and four ink supply paths corresponding to each ink are formed independently of each other. As described above, the liquid ejector device 50 in this embodiment includes an ink supply system that supplies ink from the ink tank 2 located outside the liquid ejector head 1. Note that the liquid ejector device 50 in this embodiment does not include an ink collection system for collecting ink from the liquid ejector head 1 into the ink tank 2. Therefore, the liquid ejector head 1 includes a liquid connector insertion slot 53a that connects to the ink supply tube 59 of the ink tank 2, but does not include a connector insertion slot for connecting the tube used to collect ink from the liquid ejector head 1 into the ink tank 2. Note that a liquid connector insertion slot 53a is provided for each type of ink.

[0047] exist Figure 3A In the accompanying drawings, reference numerals 54B, 54C, 54M, and 54Y represent the looping units for black, cyan, magenta, and yellow inks, respectively. The looping units have essentially the same structure, and unless otherwise specified, each looping unit in this embodiment will be referred to as "looping unit 54".

[0048] exist Figure 2 and 3A In the process, the spraying unit 3 includes two spraying modules 300, a first support member 4, a second support member 7, an electrical wiring member (electrical wiring strip) 5, and an electrical contact substrate 6. For example... Figure 3BAs shown, each spraying module 300 includes a silicon substrate 310 with a thickness of 0.5 mm to 1 mm and a plurality of spraying elements 15 disposed on one surface of the silicon substrate 310. In this embodiment, each spraying element 15 includes an electrothermal conversion element (heater) that generates heat energy as spraying energy for spraying the liquid. Electricity is supplied to each spraying element 15 via electrical wiring formed on the silicon substrate 310 using a film deposition technique.

[0049] Furthermore, on the surface of the silicon substrate 310 ( Figure 3B An outlet forming member 320 is formed on the lower surface of the substrate 310. In the outlet forming member 320, a plurality of pressure chambers 12 corresponding to a plurality of jetting elements 15 and a plurality of jetting nozzles 13 for jetting ink are formed using photolithography. Furthermore, a common supply channel 18 and a common collection channel 19 are formed in the silicon substrate 310. Additionally, in the silicon substrate 310, a supply connection channel 323 is formed connecting the common supply channel 18 and the pressure chambers 12 to each other, and a collection connection channel 324 is formed connecting the common collection channel 19 and the pressure chambers 12 to each other. In this embodiment, a jetting module 300 is configured to jet two types of ink. Specifically, in… Figure 3A Of the two injection modules shown, the one located in Figure 3A The 300 jetting module on the left side of the middle section jets black and cyan ink. Figure 3A The jetting module 300 on the right jets magenta and yellow inks. Note that this combination is merely an example; any combination of inks can be used. The configuration can allow one jetting module to jet one type of ink or three or more types of ink. The two jetting modules 300 do not necessarily jet the same amount of ink of the same type. The configuration can include only one jetting module 300, or three or more jetting modules 300. Furthermore, in... Figure 3A and 3B In the example shown, for ink of one color, two rows of nozzles extending in the Y direction are formed. For each of the plurality of nozzles 13 forming each nozzle row, a pressure chamber 12, a common supply channel 18, and a common collection channel 19 are formed.

[0050] The ink supply port and ink collection port, described later, are formed on the back surface of the silicon substrate 310. Figure 3B (On the upper surface of the middle). Ink is supplied from ink supply channel 48 to multiple common supply channels 18 through ink supply port. Ink is collected from multiple common collection channels 19 into ink collection channel 49 through ink collection port.

[0051] Note that the ink supply port and ink collection port correspond to the openings used for supplying and collecting ink during the forward ink cycle, as described later. Specifically, during the forward ink cycle, ink is supplied from the ink supply port into the common supply channel 18, and ink is collected from the common collection channel 19 into the ink collection port. Note that an ink cycle in which the ink flows in the opposite direction can also be performed. In this case, ink is supplied from the aforementioned ink collection port into the common collection channel 19, and ink is collected from the common supply channel 18 into the ink supply port.

[0052] like Figure 3A As shown, the back surface of the injection module 300 ( Figure 3A The upper surface of the middle part is adhesively fixed to one surface of the first support member 4. Figure 3A (The lower surface of the substrate). An ink supply channel 48 and an ink collection channel 49 are formed in the first support member 4, extending from one surface of the first support member 4 to the opposite surface of the first support member 4. An opening on one side of the ink supply channel 48 communicates with the aforementioned ink supply port in the silicon substrate 310. An opening on the same side of the ink collection channel 49 communicates with the aforementioned ink collection port in the silicon substrate 310. Note that the ink supply channel 48 and the ink collection channel 49 are provided independently for each type of ink.

[0053] Additionally, it has an opening 7a for inserting the injection module 300 (see...). Figure 2 The second support member 7 is adhesively fixed to one surface of the first support member 4. Figure 3A (The lower surface of the ink jet module 300). The electrical wiring component 5, which is to be electrically connected to the ink jet module 300, is held on the second support component 7. The electrical wiring component 5 is a component for applying electrical signals for ink jetting to the ink jet module 300. The electrical connection between the ink jet module 300 and the electrical wiring component 5 is sealed with a sealant (not shown) to protect it from ink corrosion and external impacts.

[0054] Furthermore, the electrical contact substrate 6 is bonded to the end 5a of the electrical wiring member 5 by thermo-press bonding using an anisotropic conductive film (not shown) (see [link]). Figure 2 The electrical wiring component 5 and the electrical contact substrate 6 are electrically connected to each other. The electrical contact substrate 6 has an external signal input terminal (not shown) for receiving electrical signals from the liquid jetting device 50.

[0055] In addition, a connecting member 8 is provided between the first support member 4 and the circulation unit 54. Figure 3A In the connecting member 8, a supply port 88 and a collection port 89 are formed for each type of ink. Through the supply port 88 and the collection port 89, the ink supply channel 48 and the ink collection channel 49 in the first support member 4 communicate with each other with the channels formed in the circulation unit 54. Incidentally, in Figure 3AIn this configuration, supply port 88B and collection port 89B are used for black ink, and supply port 88C and collection port 89C are used for cyan ink. Additionally, supply port 88M and collection port 89M are used for magenta ink, and supply port 88Y and collection port 89Y are used for yellow ink.

[0056] Note that the openings at one end of the ink supply channel 48 and the ink collection channel 49 in the first support member 4 have small opening areas that match the ink supply port and ink collection port in the silicon substrate 310. On the other hand, the openings at the other end of the ink supply channel 48 and the ink collection channel 49 in the first support member 4 have larger shapes, and their opening areas are the same as the opening areas formed in the bonding member 8 to match the channels in the circulation unit 54. This configuration can suppress the increase in channel resistance of the ink collected from each collection channel. Note that the shapes of the openings at one end and the other end of the ink supply channel 48 and the ink collection channel 49 are not limited to the examples described above.

[0057] In the liquid jet head 1 with the above-described structure, ink supplied to the circulation unit 54 flows through the supply port 88 in the connecting member 8 and the ink supply channel 48 in the first support member 4, and flows from the ink supply port in the jet module 300 into the common supply channel 18. Thereafter, the ink flows from the common supply channel 18 into the pressure chamber 12 through the supply connection channel 323. As the jet element 15 is driven, a portion of the ink flowing into the pressure chamber is ejected from the jet port 13. The remaining ink that is not ejected flows from the pressure chamber 12 through the collection connection channel 324 and the common collection channel 19, and flows from the ink collection port into the ink collection channel 49 in the first support member 4. Then, the ink flowing into the ink collection channel 49 flows into the circulation unit 54 through the collection port 89 in the connecting member 8 and is collected.

[0058] <Components of a Loop Unit>

[0059] Figure 4 This is a schematic external view of a circulation unit 54 for a type of ink used in the printing apparatus of this embodiment. A filter 110, a first pressure regulating unit 120, a second pressure regulating unit 150, and a circulation pump 500 are arranged in the circulation unit 54. Figure 5 and 6 As shown, these components are connected by channels to form an injection module 300 for supplying ink to the liquid injection head 1 and a circulation path for collecting ink from the injection module.

[0060] <Circulation path in a liquid jet head>

[0061] Figure 5 It is a schematic vertical cross-sectional view showing the circulation path formed in the liquid jet head 1 for a type of ink (one color of ink). Figure 5The relative positions of the components (e.g., the first pressure regulating unit 120, the second pressure regulating unit 150, and the circulation pump 500) are simplified to more clearly describe the circulation path. Therefore, the relative positions of the components are consistent with those mentioned later. Figure 19 The relative positions of the various components are different. Incidentally, Figure 6 It is shown schematically. Figure 5 The diagram shows a loop path. Figure 5 and 6 As shown, the first pressure regulating unit 120 includes a first valve chamber 121 and a first pressure control chamber 122. The second pressure regulating unit 150 includes a second valve chamber 151 and a second pressure control chamber 152. The first pressure regulating unit 120 is configured such that the controlled pressure therein is higher than the controlled pressure in the second pressure regulating unit 150. In this embodiment, the two pressure regulating units 120 and 150 are used to circulate within a certain pressure range in the circulation path. Moreover, this configuration causes ink to flow through the pressure chamber 12 (ejection element 15) at a flow rate corresponding to the pressure difference between the first pressure regulating unit 120 and the second pressure regulating unit 150. Reference will be made below. Figure 5 and 6 Describe the circulation path in liquid jet head 1 and the ink flow within that path. Note that... Figure 5 and 6 The arrows in the diagram indicate the direction of ink flow.

[0062] First, we will describe how the constituent elements in the liquid jet head 1 are connected.

[0063] The ink can 2, which is located outside the liquid ejector head 1, is stored in the ink can. Figure 6 The ink in the liquid jet head 1 is supplied to an external pump 21, which is connected to a circulation unit 54 via an ink supply pipe 59 (FIG. 1). A filter 110 is arranged in the ink channel upstream of the circulation unit 54. The ink supply path downstream of the filter 110 is connected to the first valve chamber 121 of the first pressure regulating unit 120. The first valve chamber 121 is connected to... Figure 5 The connecting port 191A shown, which can be opened and closed by the first valve 190A, is connected to the first pressure control chamber 122.

[0064] The first pressure control chamber 122 is connected to the supply channel 130, the bypass channel 160, and the pump outlet channel 180 of the circulation pump 500. The supply channel 130 is connected to the common supply channel 18 via the ink supply port provided in the injection module 300. Furthermore, the bypass channel 160 is connected to the second valve chamber 151 provided in the second pressure regulating unit 150. The second valve chamber 151 is connected via… Figure 5 The connecting port 191B, shown to be opened and closed by the second valve 190B, is connected to the second pressure control chamber 152. Note that... Figure 5and 6 An example is shown where one end of the bypass channel 160 is connected to the first pressure control chamber 122 of the first pressure regulating unit 120, and the other end of the bypass channel 160 is connected to the second valve chamber 151 of the second pressure regulating unit 150. However, one end of the bypass channel 160 may be connected to the supply channel 130, and the other end of the bypass channel may be connected to the second valve chamber 151.

[0065] The second pressure control chamber 152 is connected to the collection channel 140. The collection channel 140 is connected to the common collection channel 19 via the ink collection port provided in the jetting module 300. Furthermore, the second pressure control chamber 152 is connected to the circulation pump 500 via the pump inlet channel 170. Note that... Figure 5 In the attached figure, reference numeral 170a indicates the inlet of pump inlet channel 170.

[0066] Next, the ink flow in the liquid jet head 1 with the above-described structure will be described. For example... Figure 6 As shown, the ink stored in the ink tank 2 is pressurized by an external pump 21 installed in the liquid jet device 50, becoming a positive pressure ink flow, and is supplied to the circulation unit 54 of the liquid jet head 1.

[0067] The ink supplied to the circulation unit 54 passes through the filter 110, thereby removing impurities such as dust and air bubbles. The ink then flows into the first valve chamber 121 located in the first pressure regulating unit 120. The ink pressure decreases due to the pressure loss when the ink passes through the filter 110, but the ink pressure remains positive at this point. Subsequently, with valve 190A open, the ink flowing into the first valve chamber 121 passes through the connection port 191A and flows into the first pressure control chamber 122. Due to the pressure loss when the ink passes through the connection port 191A, the pressure of the ink flowing into the first pressure control chamber 122 switches from positive to negative.

[0068] Next, the flow of ink in the circulation path will be described. The circulation pump 500 operates such that ink drawn from the pump inlet channel 170 located upstream of the circulation pump 500 is delivered to the pump outlet channel 180 located downstream of the circulation pump 500. Therefore, as the pump is driven, ink supplied to the first pressure control chamber 122 flows into the supply channel 130 and the bypass channel 160 together with ink delivered from the pump outlet channel 180. In this embodiment, although details will be described later, a piezoelectric diaphragm pump is used as the circulation pump capable of dispensing liquid, which uses a piezoelectric element attached to a diaphragm as the drive source. The piezoelectric diaphragm pump dispenses liquid by inputting a drive voltage to the piezoelectric element to change the volume of the pump chamber and alternately actuating two check valves in response to pressure changes.

[0069] Ink flowing into supply channel 130 flows from the ink supply port in the jet module 300 into pressure chamber 12 through common supply channel 18. As the jet element 15 is driven (heated), a portion of the ink is ejected from jet port 13. Furthermore, the remaining ink not used for ejection flows through pressure chamber 12 and through common collection channel 19. Thereafter, the ink flows into collection channel 140 connected to the jet module 300. The ink flowing into collection channel 140 flows into the second pressure control chamber 152 of the second pressure regulating unit 150.

[0070] On the other hand, ink flowing from the first pressure control chamber 122 into the bypass channel 160 flows into the second valve chamber 151, through the connecting port 191B, and then into the second pressure control chamber 152. Ink flowing into the second pressure control chamber 152 through the bypass channel 160 and ink collected from the collection channel 140 are drawn into the circulation pump 500 through the pump inlet channel 170 as the circulation pump 500 is driven. Then, the ink drawn into the circulation pump 500 is sent to the pump outlet channel 180 and flows back into the first pressure control chamber 122. Thereafter, ink flowing from the first pressure control chamber 122 into the second pressure control chamber 152 through the supply channel 130 and the injection module 300, as well as ink flowing into the second pressure control chamber 152 through the bypass channel 160, flows into the circulation pump 500. Then, ink is sent from the circulation pump 500 to the first pressure control chamber 122. Ink circulation is performed within the circulation path in this manner.

[0071] Here, the channel through which the first pressure regulating unit 120 and the pressure chamber 12 communicate with each other will be referred to as the "first channel," and the channel through which the pressure chamber 12 and the circulation pump 500 communicate with each other will be referred to as the "second channel." Specifically, the supply channel 130 is referred to as the "first channel," and the collection channel 140, the second pressure regulating unit 150, and the pump inlet channel 170 are collectively referred to as the "second channel." Note that the second channel does not necessarily include the second pressure regulating unit 150 and the pump inlet channel 170. Moreover, the pump outlet channel 180 will also be referred to as the "third channel." Therefore, in this embodiment, the liquid flows sequentially through the circulation pump 500, the third channel, the first pressure regulating unit 120, the first channel, the pressure chamber 12, the second channel, and the circulation pump 500 as a circulation path.

[0072] As described above, in this embodiment, the circulation pump 500 can be used to circulate the liquid through the circulation paths formed in the liquid jet head 1. This allows for the suppression of ink thickening and the precipitation of ink sedimentation components in the jet module 300. Therefore, excellent ink flowability and excellent jetting characteristics at the jet nozzle can be maintained in the jet module 300.

[0073] Furthermore, in this embodiment, the circulation path is configured to be completed within the liquid ejector head 1. Therefore, the length of the circulation path is significantly shorter compared to the case where the ink circulates between the ink tank 2, which is located outside the liquid ejector head 1, and the liquid ejector head 1. Thus, a small circulation pump can be used to circulate the ink.

[0074] Furthermore, this configuration allows only a channel for supplying ink to be included as the connection between the liquid ejector head 1 and the ink tank 2. In other words, a configuration that eliminates the need for a channel for collecting ink from the liquid ejector head 1 into the ink tank 2 is adopted. Therefore, only an ink supply pipe is needed to connect the ink tank 2 and the liquid ejector head 1, and an ink collection pipe is not required. As a result, the internal structure of the liquid ejector device 50 has a simpler configuration including fewer pipes. This can reduce the overall size of the device. In addition, the reduction in the number of pipes reduces ink pressure fluctuations caused by pipe oscillations due to the main scan of the liquid ejector head 1. Moreover, pipe oscillations during the main scan of the liquid ejector head 1 increase the drive load on the carriage motor that drives the carriage 60. Therefore, the reduction in the number of pipes reduces the drive load on the carriage motor, which allows for simplification of the main scan mechanism, including the carriage motor and the like. Furthermore, since it is not necessary to collect ink from the liquid ejector head 1 into the ink tank, the external pump 21 can also be miniaturized. As described above, according to this embodiment, the liquid ejector device 50 can be miniaturized and its cost reduced.

[0075] <Pressure Regulation Unit>

[0076] Figures 7A to 7C This is a view showing an example of a pressure regulating unit. (Refer to...) Figures 7A to 7C The construction and operation of the pressure regulating units (first pressure regulating unit 120 and second pressure regulating unit 150) incorporated in the liquid injection head 1 described above will be described in more detail. Note that the first pressure regulating unit 120 and the second pressure regulating unit 150 have substantially the same construction. Therefore, the following description will be given using the first pressure regulating unit 120 as an example. For the second pressure regulating unit 150, in Figures 7A to 7C Only the reference numerals for the parts corresponding to the first pressure regulating unit are shown in the figures. In the case of the second pressure regulating unit 150, the first valve chamber 121 and the first pressure control chamber 122 described below should be understood as the second valve chamber 151 and the second pressure control chamber 152, respectively. The pressure regulating unit (first pressure regulating unit 120 and second pressure regulating unit 150) is a mechanism that generates a pressure difference between the interior of the supply channel and the interior of the collection channel.

[0077] The first pressure regulating unit 120 has a first valve chamber 121 and a first pressure control chamber 122 formed in a cylindrical housing 125. The first valve chamber 121 and the first pressure control chamber 122 are separated by a partition 123 provided within the cylindrical housing 125. However, the first valve chamber 121 communicates with the first pressure control chamber 122 through a communication port 191 formed in the partition 123. A valve 190 is provided in the first valve chamber 121, which switches between allowing communication between the first valve chamber 121 and the first pressure control chamber 122 through the communication port 191 and blocking communication. The valve 190 is held in a position opposite to the communication port 191 by a valve spring 200 and has a configuration that allows close contact with the partition 123 by a biasing force from the valve spring 200. The valve 190 blocks ink flow through the communication port 191 by its close contact with the partition 123. Specifically, the valve spring 200 is a valve biasing member that biases the valve 190 in the closing direction. Note that the portion of valve 190 that contacts the partition 123 is preferably formed of an elastic member to enhance the tightness of the contact with the partition 123. Furthermore, a valve shaft 190a, inserted through the communication port 191, is provided in a protruding manner on the central portion of valve 190. By pressing this valve shaft 190a against the biasing force from the valve spring 200, valve 190 separates from the partition 123, thereby allowing ink to flow through the communication port 191. In the following text, the state in which valve 190 blocks ink flow through the communication port 191 will be referred to as the "closed state," while the state in which ink can flow through the communication port 191 will be referred to as the "open state."

[0078] The opening of the cylindrical housing 125 is closed by a flexible member 230 and a pressing plate 210. These flexible members 230, the pressing plate 210, the peripheral wall of the housing 125, and the partition 123 form a first pressure control chamber 122. The pressing plate 210 is configured to move with the flexible member 230. While there are no particular limitations on the materials of the pressing plate 210 and the flexible member 230, for example, the pressing plate 210 can be made as a molded resin part, and the flexible member 230 can be made of a resin film. In this case, the pressing plate 210 can be fixed to the flexible member 230 by heat welding. Note that the pressing plate 210 in the first pressure control chamber 122 will be referred to as "first pressing plate 210A", and the pressing plate 210 in the second pressure control chamber 152 will be referred to as "second pressing plate 210B". Furthermore, the flexible member 230 in the first pressure control chamber 122 will be referred to as "first flexible member 230A", and the flexible member 230 in the second pressure control chamber 152 will be referred to as "second flexible member 230B".

[0079] A pressure adjusting spring 220 (biasing member) is provided between the pressing plate 210 and the partition 123. For example... Figure 7AAs shown, the pressing plate 210 and the flexible member 230 are biased by the biasing force from the pressure regulating spring 220 in the direction that increases the internal volume of the first pressure control chamber 122. Furthermore, as the pressure in the first pressure control chamber 122 decreases, the pressing plate 210 and the flexible member 230 resist the pressure from the pressure regulating spring 220 and shift in the direction that decreases the internal volume of the first pressure control chamber 122. Then, when the internal volume of the first pressure control chamber 122 decreases to a certain volume, the pressing plate 210 abuts against the valve shaft 190a of the valve 190. When the internal volume of the first pressure control chamber 122 subsequently decreases further, the valve 190, together with the valve shaft 190a, overcomes the biasing force from the valve spring 200 and moves, thereby separating from the partition 123. As a result, the communication port 191 changes to the open state. Figure 7B (State of the pressure adjustment spring 220 in the first pressure control chamber 122 will be referred to as the "first bias member", and the pressure adjustment spring 220 in the second pressure control chamber 152 will be referred to as the "second bias member".)

[0080] In this embodiment, the connection in the circulation path is configured such that when the connection port 191 is in the open state, the pressure in the first valve chamber 121 is higher than the pressure in the first pressure control chamber 122. Thus, when the connection port 191 is in the open state, ink flows from the first valve chamber 121 into the first pressure control chamber 122. The inflow of ink causes the flexible member 230 and the pressing plate 210 to shift in a direction that increases the internal volume of the first pressure control chamber 122. As a result, the pressing plate 210 separates from the valve shaft 190a of the valve 190, and the valve 190 is brought into close contact with the partition 123 by the biasing force from the valve spring 200, causing the connection port 191 to be in the closed state. Figure 7C (state).

[0081] As described above, in the first pressure regulating unit 120 of this embodiment, when the pressure in the first pressure control chamber 122 drops below a certain pressure (for example, when the negative pressure increases), ink flows in from the first valve chamber 121 through the connecting port 191. This configuration limits further pressure reduction in the first pressure control chamber 122. Therefore, the pressure in the first pressure control chamber 122 is controlled to be maintained within a certain range.

[0082] The pressure in the first pressure control chamber 122 will be described in more detail next.

[0083] Consider the following state, wherein, as described above, the flexible member 230 and the pressing plate 210 are displaced according to the pressure in the first pressure control chamber 122, such that the pressing plate 210 abuts against the valve shaft 190a and the communication port 191 is in the open state. Figure 7B(The state at which the forces acting on the pressing plate 210 are in this state). The relationship between the forces acting on the pressing plate 210 at this time is represented by the following equation 1.

[0084] P2×S2+F2+(P1-P2)×S1+F1=0…Equation 1

[0085] Furthermore, for P2, Equation 1 is summarized as follows.

[0086] P2 = - (F1 + F2 + P1×S1) / (S2-S1)...: Equation 2

[0087] P1: Pressure in the first valve chamber 121 (indicating pressure)

[0088] P2: Pressure in the first pressure control chamber 122 (indicating pressure)

[0089] F1: Spring force of valve spring 200

[0090] F2: Spring force of pressure regulating spring 220

[0091] S1: Pressure receiving area of ​​valve 190

[0092] S2: Pressure receiving area of ​​flexible member 230 and pressing plate 210

[0093] The "pressure receiving area" in this embodiment will now be described. First, the pressure receiving area of ​​valve 190 is the area of ​​the region of valve 190 that receives the force generated by the pressure difference between P1 and P2. It can be defined as the area of ​​the region of valve 190 inside the portion of valve 190 that abuts against the partition 123 when valve 190 is in contact with the partition 123. For example, the portion of valve 190 that abuts against the partition 123 has the following characteristics: Figures 7A to 7C In the case of the elastic member with the cross-section shown, the region inside the abutment portion can be described in other words as a region formed by a line segment extending along the portion with the smallest gap between the elastic member and the partition 123.

[0094] The pressure-receiving area of ​​the flexible member 230 and the pressing plate 210 is the area of ​​the portion of the flexible member 230 and the pressing plate 210 that receives the force generated by the pressure difference between the atmosphere outside the first pressure control chamber 122 and the pressure inside the first pressure control chamber 122. Specifically, the pressure-receiving area of ​​the flexible member 230 and the pressing plate 210 is equivalent to the area of ​​the pressing plate 210 plus the area of ​​the flexible member 230 excluding the area from the portion connected to the first pressure control chamber 122 to the bending portion. Here, the bending of the flexible member 230 changes according to the pressure in the first pressure control chamber 122, and therefore the pressure-receiving area of ​​the flexible member 230 and the pressing plate 210 can also change. To describe this more specifically, the flexible member 230 in Figure 7CIt is essentially not bent in its current state. Therefore, in Figure 7C In this state, the pressure receiving area of ​​the flexible member 230 and the pressing plate 210 is the sum of the area of ​​the pressing plate 230 and the area of ​​the flexible member 210 (not the area of ​​the flexible member itself, but the area of ​​the flexible member projected onto a plane parallel to the pressing plate). On the other hand, in Figure 7B In this state, the flexible member 230 is bent. In this state, the area of ​​the flexible member 230, excluding the area from the portion connected to the first pressure control chamber 122 to the bent portion, corresponds to the area from the apex of the bend to the portion connected to the pressing plate. Therefore, in Figure 7B In this context, the pressure receiving area of ​​the flexible member 230 and the pressure plate 210 is the sum of the area of ​​the pressure plate 210 and the area of ​​the flexible member 230 projected from the apex of its bend to the portion connected to the pressure plate 210 onto a plane parallel to the pressure plate 210.

[0095] As described above, the pressure receiving areas of the flexible member 230 and the pressing plate 210 vary. Therefore, in this embodiment, when the opening is opened via valve 190, the pressure receiving areas of the flexible member 230 and the pressing plate 210 of the second pressure regulating unit need to be smaller than those of the flexible member and the pressing plate of the first pressure regulating unit. Specifically, when the second opening (connection port 191B) is opened via the second valve 190B, the pressure receiving areas of the second flexible member 230B and the second pressing plate 210B in the second pressure control chamber 152 need to be smaller than those of the first flexible member 230A and the first pressing plate 210A in the first pressure control chamber 122 when the first opening (connection port 191A) is opened via the first valve 190A. This feature can shorten the time spent by the circulating liquid jetting device in a circulating state stopping circulation.

[0096] Here, the directions in which the spring force F1 of the valve spring 200 and the spring force F2 of the pressure regulating spring 220 push the valve 190 and the press plate 210 are defined as the positive direction. Figures 7A to 7C (to the right in the middle). Moreover, this structure ensures that the pressure P1 in the first valve chamber 121 and the pressure P2 in the first pressure control chamber 122 satisfy the relationship P1≥P2.

[0097] When the connection port 191 is switched to the open state, the pressure P2 in the first pressure control chamber 122 is determined by Equation 2. Furthermore, because of this configuration, when the connection port 191 is switched to the open state, the relationship P1 ≥ P2 is satisfied, therefore ink flows from the first valve chamber 121 into the first pressure control chamber 122. As a result, the pressure P2 in the first pressure control chamber 122 no longer decreases, and the pressure P2 remains within a specific range.

[0098] On the other hand, such as Figure 7C As shown, the relationship between the forces acting on the pressing plate 210 when the pressing plate 210 is not in contact with the valve shaft 190a and the connecting port 191 is in the closed state is represented by the following equation 3.

[0099] P3×S3+F3=0…Equation 3

[0100] Here, for P3, Equation 3 is summarized as follows.

[0101] P3 = -F3 / S3…Equation 4

[0102] F3: The spring force of the pressure regulating spring 220 when the pressing plate 210 is not in contact with the valve shaft 190a.

[0103] P3: Pressure (indicating pressure) in the first pressure control chamber 122 when the pressure plate 210 is not in contact with the valve shaft 190a.

[0104] S3: Pressure receiving area of ​​the pressing plate 210 when the pressing plate 210 is not in contact with the valve 190

[0105] here, Figure 7C The pressing plate 210 and the flexible member 230 are shown along... Figure 7C The pressure P3 in the first pressure control chamber 122, the spring force F3 of the pressure regulating spring 220, and the pressure receiving area S3 of the pressing plate 210 are shifted to the right until they reach their limit. Figure 7C The state changes due to the amount of displacement. Specifically, the pressure plate 210 and the flexible member 230 relative to each other... Figure 7C Its own location in Figure 7C In the case on the left side, the pressure receiving area S3 of the pressing plate 210 is smaller, and the spring force F3 of the pressure adjusting spring 220 is larger. Therefore, the pressure P3 in the first pressure control chamber 122 is smaller according to the relationship in Equation 4. Therefore, according to Equations 2 and 4, the pressure P3 in the first pressure control chamber 122 is smaller when it is from... Figure 7B The state changed to Figure 7CThe negative pressure gradually increases as it approaches the positive pressure side. Specifically, as the pressure plate 210 and flexible member 230 gradually move to the right from the open state of the communication port 191 until the internal volume of the first pressure control chamber reaches the limit of their displacement, the pressure in the first pressure control chamber 122 gradually increases. In other words, the negative pressure decreases. In this embodiment, the first pressure regulating unit 120 regulates the pressure of the liquid in the first channel, and the second pressure regulating unit 150 regulates the pressure of the liquid in the pump inlet channel 170 (inlet channel).

[0106] <Ink flow within the liquid jet head>

[0107] Figures 8A to 8E This is a diagram depicting the ink flow within a liquid ejector head. (Refer to...) Figures 8A to 8E This describes the ink circulation that occurs within the liquid ejector head 1. To more clearly illustrate the ink circulation path, a simplified version is provided. Figures 8A to 8E The relative positions of the components (e.g., the first pressure regulating unit 120, the second pressure regulating unit 150, and the circulation pump 500) are specified. Therefore, the relative positions of the components are related to those mentioned later. Figure 23 The relative positions of the various components are different. Figure 8A The diagram schematically illustrates the ink flow during a printing operation, which is performed by ejecting ink from nozzle 13. Note that... Figure 8A The arrows in the diagram indicate ink flow. In this embodiment, both the external pump 21 and the circulation pump 500 are started to drive in order to perform a printing operation. Incidentally, the external pump 21 and the circulation pump 500 can be driven regardless of whether a printing operation is to be performed. The external pump 21 and the circulation pump 500 do not need to be driven in conjunction with each other, but can be driven independently of each other.

[0108] During printing, the circulation pump 500 is in the ON (driven) state, causing ink flowing from the first pressure control chamber 122 to flow into the supply channel 130 and the bypass channel 160. The ink that has flowed into the supply channel 130 passes through the ejection module 300 and then flows into the collection channel 140. Thereafter, the ink is supplied to the second pressure control chamber 152.

[0109] On the other hand, ink flowing from the first pressure control chamber 122 into the bypass channel 160 flows into the second pressure control chamber 152 through the second valve chamber 151. The ink flowing into the second pressure control chamber 152 passes through the pump inlet channel 170, the circulation pump 500, and the pump outlet channel 180, and then flows back into the first pressure control chamber 122. At this time, based on the relationship in Equation 2 above, the controlled pressure in the first valve chamber 121 is set higher than the controlled pressure in the first pressure control chamber 122. Therefore, the ink in the first pressure control chamber 122 does not flow into the first valve chamber 121, but is instead supplied back to the injection module 300 through the supply channel 130. The ink flowing into the injection module 300 flows back into the first pressure control chamber 122 through the collection channel 140, the second pressure control chamber 152, the pump inlet channel 170, the circulation pump 500, and the pump outlet channel 180. The ink circulation completed within the liquid injection head 1 is performed as described above.

[0110] In the aforementioned ink circulation, the pressure difference between the controlled pressure in the first pressure control chamber 122 and the controlled pressure in the second pressure control chamber 152 determines the ink circulation volume (flow rate) within the ejection module 300. Furthermore, this pressure difference is set to obtain a circulation volume capable of suppressing ink thickening near the ejection nozzle in the ejection module 300. Incidentally, the ink consumed during printing is supplied from the ink tank 2 through the filter 110 and the first valve chamber 121 to the first pressure control chamber 122. How the consumed ink is supplied will now be described in detail. The amount of ink consumed during printing decreases as ink in the circulation path decreases. Therefore, the pressure in the first pressure control chamber 122 decreases, resulting in a reduction in ink within the first pressure control chamber. As the ink in the first pressure control chamber 122 decreases, the internal volume of the first pressure control chamber 122 decreases accordingly. As this internal volume of the first pressure control chamber 122 decreases, the connection port 191A becomes open, allowing ink to be supplied from the first valve chamber 121 to the first pressure control chamber 122. As ink supplied from the first valve chamber 121 passes through the connection port 191A, a pressure loss occurs in the supplied ink. As ink flows into the first pressure control chamber 122, the positive pressure of the ink switches to a negative pressure. As ink flows from the first valve chamber 121 into the first pressure control chamber 122, the pressure in the first pressure control chamber increases. When the internal volume of the first pressure control chamber increases, the connection port 191A changes to a closed state. As described above, the connection port 191A repeatedly switches between an open and closed state according to ink consumption. Incidentally, when ink is not being consumed, the connection port 191A remains in the closed state.

[0111] Figure 8BThe diagram schematically illustrates the ink flow immediately following the completion of the printing operation and the circulator pump 500 being switched to the OFF state (stopped state). When the printing operation is complete and the circulator pump 500 is switched to the OFF state, the pressure in the first pressure control chamber 122 and the pressure in the second pressure control chamber 152 are both controlled pressures used in the printing operation. Therefore, the ink flows according to the pressure difference between the pressure in the first pressure control chamber 122 and the pressure in the second pressure control chamber 152. Figure 8B The movement is as shown. Specifically, ink flow continues to be generated from the first pressure control chamber 122 through the supply channel 130 to the jet module 300 and then through the collection channel 140 to the second pressure control chamber 152. In addition, ink flow continues to be generated from the first pressure control chamber 122 through the bypass channel 160 and the second valve chamber 151 to the second pressure control chamber 152.

[0112] The amount of ink flowing from the ink tank 2 to the second pressure control chamber 152 via these ink streams is supplied from the ink tank 2 through the filter 110 and the first valve chamber 121 to the first pressure control chamber 122. Therefore, the internal volume of the first pressure control chamber 122 remains constant. According to the relationship in Equation 2 above, with the internal volume of the first pressure control chamber 122 constant, the spring force F1 of the valve spring 200, the spring force F2 of the pressure regulating spring 220, the pressure receiving area S1 of the valve 190, and the pressure receiving area S2 of the press plate 210 remain constant. Therefore, the pressure in the first pressure control chamber 122 is determined based on the change in the pressure (indicating pressure) P1 in the first valve chamber 121. Thus, with the pressure P1 in the first valve chamber 121 remaining constant, the pressure P2 in the first pressure control chamber 122 is maintained at the same pressure as the controlled pressure during printing operation.

[0113] On the other hand, the pressure in the second pressure control chamber 152 changes over time according to the change in internal volume caused by the inflow of ink from the first pressure control chamber 122. Specifically, the pressure in the second pressure control chamber 152 changes according to Equation 2 until the connecting port 191... Figure 8B The state changes to such Figure 8C The diagram shows a closed state where communication between the second valve chamber 151 and the second pressure control chamber 152 is disrupted. Afterward, the pressure plate 210 is no longer in contact with the valve shaft 190a, causing the communication port 191 to change to a closed state. Then, as... Figure 8D As shown, ink flows from collection channel 140 into the second pressure control chamber 152. This inflow of ink causes displacement of the pressing plate 210 and the flexible member 230. The pressure in the second pressure control chamber 152 varies according to Equation 4. Specifically, the pressure increases until the internal volume of the second pressure control chamber 152 reaches its maximum.

[0114] Note that once it reaches... Figure 8CIn this state, ink no longer flows from the first pressure control chamber 122 into the second pressure control chamber 152 through the bypass channel 160 and the second valve chamber 151. Therefore, the ink flow to the second pressure control chamber 152 through the collection channel 140 is only generated after the ink in the first pressure control chamber 122 is supplied to the injection module 300 through the supply channel 130. As described above, ink moves from the first pressure control chamber 122 to the second pressure control chamber 152 according to the pressure difference between the pressure in the first pressure control chamber 122 and the pressure in the second pressure control chamber 152. Therefore, when the pressure in the second pressure control chamber 152 becomes equal to the pressure in the first pressure control chamber 122, the ink stops moving. That is, the liquid injection head 1 enters a cycle-stopped state.

[0115] Furthermore, when the pressure in the second pressure control chamber 152 is equal to the pressure in the first pressure control chamber 122, the second pressure control chamber 152 expands to... Figure 8D The state shown. In the second pressure control chamber 152, as indicated. Figure 8D In the case of expansion shown, the ink reservoir portion can be maintained within the second pressure control chamber 152. When in such a situation... Figure 8D When the circulating pump 500 is driven while the ink is held in the reservoir section, the ink in the reservoir section is supplied to the first pressure control chamber 122 via the circulating pump 500. Therefore, as shown... Figure 8E As shown, the ink volume in the first pressure control chamber 122 increases, causing the flexible member 230 and the pressing plate 210 to shift along the expansion direction. Then, as the circulation pump 500 continues to be driven, the state within the circulation path changes. Figure 8A The state shown.

[0116] Note that in the above description, Figure 8A This has already been described as an example of ink circulation during a printing operation. However, as previously stated, ink can circulate even without a printing operation. Even in this case, the ink circulates in response to the driving and stopping of the circulation pump 500. Figures 8A to 8E The flow is shown.

[0117] As previously described, after the circulation pump 500 is stopped, ink moves from the first pressure control chamber 122 to the second pressure control chamber 152 based on the pressure difference between the pressure in the first pressure control chamber 122 and the pressure in the second pressure control chamber 152. Then, when the pressure in the second pressure control chamber 152 becomes equal to the pressure in the first pressure control chamber 122, the ink movement stops. In other words, the circulation stops. Therefore, the smaller the pressure difference between the controlled pressure in the first pressure control chamber 122 and the controlled pressure in the second pressure control chamber 152, the shorter the time required to stop the circulation. Furthermore, the greater the change in pressure in the second pressure control chamber 152 corresponding to the amount of ink flowing into it, the shorter the time required to stop the circulation. In this embodiment, with regard to such a relationship, an example of shortening the time required to stop the circulation in response to executing control to stop the circulation from the circulation state (driving stop of the circulation pump 500) will be described.

[0118] Incidentally, if wiping operations such as wiping the surface of the ejection nozzle 13 of the ejection module 300, or suction recovery operations such as covering and suction recovery operations of the ejection nozzle 13 are performed while the circulation in the ejection module 300 has not stopped, ink of other colors may enter the ejection nozzle. If the circulation is performed while ink of other colors has entered the ejection nozzle 13, the circulation will transport the ink into the circulation path. In this case, it is difficult to eject only ink of other colors. Therefore, color mixing may occur in the liquid ejection head. In particular, when the circulation unit 54 is mounted on the carriage 60 as in this embodiment, the amount of ink in each circulation path is less than when ink circulation involving the printer body is performed. Therefore, there is a possibility that even a small amount of color mixing can greatly affect the image quality. Therefore, when performing maintenance operations such as wiping or recovery operations after printing, color mixing can be suppressed by performing maintenance operations after a certain waiting time. From the viewpoint of increasing productivity, such waiting time is preferably short. Specifically, the time from the end of printing until the circulation stops is preferably short.

[0119] <Shorten the time spent in the stopping loop>

[0120] The following will describe in detail an example of reducing the time spent in the cycle path by stopping the cycle in response to stopping the cycle pump 500 from the cycle state.

[0121] Figure 9A and 9B This is a diagram depicting the construction of the second pressure regulating unit 150. (Will use...) Figure 9A and 9BThe pressure receiving areas S2 and S3 of the movable portion of the second pressure regulating unit 150, formed by the flexible member 230 and the pressing plate 210, are described. Pressure receiving area S2 is the area of ​​the second flexible member 230B and the second pressing plate 210B that receives the force generated by the pressure difference between the atmosphere outside the second pressure control chamber 152 and the pressure inside the second pressure control chamber 152. Pressure receiving area S3 is the area of ​​the second pressing plate 210B that receives the force generated by the pressure difference between the atmosphere outside the second pressure control chamber 152 and the pressure inside the second pressure control chamber 152 when the second pressing plate 210B is not in contact with the second valve 190B. Note that the pressure receiving areas S2 and S3 shown are equal to the pressure receiving areas in the example described using FIG. 7. (The last sentence appears to be incomplete and possibly refers to a technical explanation of the process.) Figure 9A and 9B The relationship between these pressure receiving areas is described in more detail.

[0122] Figure 9A This diagram shows the state where the connector 191B is in the open position. Specifically, Figure 9A The diagram shows a state where the movable part of the second pressure regulating unit 150 has been retracted, thereby reducing the internal volume of the second pressure control chamber 152. Figure 9B This diagram shows the connection port 191B in the closed state. The diagram also shows that the movable portion of the second pressure regulating unit 150 has been displaced, thus maximizing the internal volume of the second pressure control chamber 152.

[0123] In the displaceable part Figure 9A In the case of displacement under the state, the second flexible member 230B is as follows Figure 9A The bending is shown. The second flexible member 230B preferably has a small resistance to bending, so that the displaceable portion can move stably and transform... Figure 9A The state (bent state). For example, consider the bag height H and width W of the second flexible member 230B. Figure 9BAs shown, when the second flexible member 230B is displaced to the position of maximum internal volume of the second pressure control chamber 152, the bag height H corresponds to the horizontal distance from the housing 155 to the second pressing plate 210B during use. That is, the bag height H corresponds to the possible amount of movement away from the plane perpendicular to the plane at the opening of the housing 155 (in this example, the horizontal direction during use). The width W of the second flexible member 230B is a value related to the projected area of ​​the second pressing plate 210B on the plane at the opening of the housing 155. Specifically, "the value obtained by subtracting the width of the second pressing plate 210B from the width of the housing 155 / 2" corresponds to the width W of the second flexible member 230B. The width W of the second flexible member 230B also corresponds to the vertical distance from the end of the second pressing plate 210B to the housing 155 during use. Note that the example in this embodiment represents an example in the vertical direction, but the orientation is not limited to this example. For example, Figure 9A and 9B It can rotate 90 degrees, in which case the direction is horizontal. Furthermore, the orientation can be any angle within 360 degrees. The bending angle θ is determined based on the bag height H and width W of the second flexible member 230B (see...). Figure 9A When the bending angle θ is relatively large, the second flexible member 230B has relatively low resistance to bending. Therefore, the configuration aims for H / W to be less than or equal to a specific value so that the bending angle θ can be relatively large.

[0124] Here, we consider the case where H / W is fixed to a value less than or equal to a specific value. In this case, the width W of the second flexible member 230B is uniquely determined based on the bag height H. Therefore, when the pressure receiving area S2 is a specific value in the open state of the second valve 190B, since the bag height H and width W of the second flexible member 230B are determined, the maximum value of the pressure receiving area S3, i.e., the S3 in the state where the second pressing plate 210B is furthest from the housing 155 in the horizontal direction during use, is also uniquely determined. Incidentally, as will be mentioned later... Figure 11BAs shown, the pressure receiving area S3 can be derived as the area of ​​a circle with diameter D1. Furthermore, with the pressure plate 210 and the opening of the housing 155 on the same plane, and with the connection port 191 in an open state, the pressure receiving area S2 can also be derived as the area of ​​a circle with diameter D1-W. Specifically, under the above conditions, the pressure receiving area can be expressed as "S3 = (D1 / 2)^2 × π" and "S2 = (D1 / 2 – W / 2)^2 × π". In this case, the pressure receiving area ratio S3 / S2 is considered. As mentioned above, S3 is uniquely determined by S2. Therefore, S3 / S2 can be expressed as a function of only S2. Here, it is obvious that the smaller the value of S2, the larger the value of the pressure receiving area ratio S3 / S2 as a function of S2. Considering equations 2 and 4 mentioned above, when the controlled pressure P2 is set to a given value, the pressure ratio P3 / P2 increases as the pressure receiving area ratio S3 / S2 increases. Specifically, when the pressure from... Figure 9A The state (with pressure P2) transforms into Figure 9B In the state of pressure P3, the smaller the pressure receiving area S2 of the second flexible member 230B and the second pressing plate 210B, the greater the pressure change in the second pressure control chamber 152. Furthermore, from... Figure 9A The state changes to Figure 9B In the given state, the smaller the pressure receiving area S2 of the second flexible member 230B and the second pressing plate 210B, the smaller the change in the internal volume of the second pressure control chamber 152. Therefore, the smaller S2 is, the greater the change in pressure in the second pressure control chamber 152 in response to the change in its internal volume.

[0125] As mentioned earlier, the greater the pressure response in the second pressure control chamber 152 to changes in its internal volume (i.e., the amount of ink flowing into it), the shorter the time required to stop the circulation in the ejection module 300 after the circulation pump 500 stops following printing. Therefore, by reducing the pressure receiving area S2 of the second pressure control chamber 152, the time required to stop the circulation can be shortened.

[0126] Note that the pressure receiving area S2 of the second pressure control chamber 152 cannot be reduced indefinitely. The lower limit of the pressure receiving area S2 of each of the first pressure control chamber 122 and the second pressure control chamber 152 is limited by the controlled pressure. The lower limit value of the pressure receiving area S2 will be described below. The following applies to both the first pressure control chamber 122 and the second pressure control chamber 152. First, in order to achieve the injection characteristics, a target controlled pressure P2 is set in each chamber. While minimizing the pressure receiving area S2 for the target controlled pressure P2, the spring force F1 of the valve spring 200 (valve biasing member) in Equation 2 is limited. In order for the valve 190 to close the connection port 191, the spring force F1 of the valve spring 200 in Equation 2 needs to be a certain level of force. Therefore, in Equation 2, the value of the spring force F1 of the valve spring 200 is set to a specific fixed value or higher. Thus, in Equation 2, the smaller the controlled pressure P2, the smaller the pressure receiving area S2 can be. Here, as mentioned earlier, the controlled pressure in the first pressure control chamber 122 is set to be higher than the controlled pressure in the second pressure control chamber 152. Therefore, the pressure receiving area S2 of the second pressure control chamber 152 can be smaller than the pressure receiving area S2 of the first pressure control chamber 122. This further reduces the time spent on the stop cycle.

[0127] That is, although the lower limit of the pressure receiving area S2 of each of the first pressure control chamber 122 and the second pressure control chamber 152 is limited by the controlled pressure, the time spent on stopping the cycle can be shortened by making the pressure receiving area S2 of the second pressure control chamber 152 smaller than the pressure receiving area S2 of the first pressure control chamber 122.

[0128] Typically, systems that utilize the pressure difference generated by changing the controlled pressure in two pressure control mechanisms (pressure regulating units) to perform cycles use pressure control mechanisms of the same size and shape. This is because, in terms of component versatility and manufacturing method versatility, it is preferable to manufacture pressure control mechanisms of the same size and shape. Springs incorporated in the pressure control mechanisms are given different characteristics to generate the pressure difference. In this embodiment, each pressure regulating unit is intentionally given a different size or shape to generate the pressure difference, and the time spent stopping the cycle is also reduced.

[0129] Furthermore, by making S2 smaller, the circulation unit 54 can be miniaturized, thereby enabling the liquid jet head 1 to be miniaturized. In particular, for serial scanning types, a lighter carriage weight is preferable, and reducing the size of the liquid jet head 1 can reduce the carriage weight.

[0130] Figure 10A and 10B This is a diagram depicting the structure of the second pressure regulating unit 150. (Will be used...) Figure 10A and10B Describe the width W and bag height H of the second flexible member 230B. (Compared to...) Figure 9A similar, Figure 10A This diagram shows the connection port 191B in the open state. (Compared to...) Figure 9B similar, Figure 10B This diagram shows that the connection port 191B is in the closed state. Figure 10A and 10B They are respectively Figure 9A and 9B The diagram shows the case where the width W and bag height H of the second flexible member 230B become a larger width W' and a smaller bag height H'. In this case, the pressure receiving area S2' is smaller than... Figure 9A The pressure receiving area S2 is shown. This indicates that the pressure receiving area ratio S3 / S2' is greater than the pressure receiving area ratio S3 / S2. As mentioned earlier, the larger S3 / S2 is, the larger the pressure ratio P3 / P2 is, and the shorter the time required to stop the cycle can be. The above describes a structure in which both the width W and the bag height H of the second flexible member 230B are changed, but a similar effect can be obtained by changing only one of them. In other words, decreasing H / W increases the pressure receiving area ratio S3 / S2, and thus increases the pressure ratio P3 / P2.

[0131] Next, the spring force F1 of valve spring 200 will be described. As mentioned earlier, the smaller F1 (and F2) is, the smaller the pressure receiving area S2 can be; however, by making F1 sufficiently large, the time spent stopping the cycle can be relatively short. According to equations 2 and 4, as the pressing plate 210 changes from a state of contact with valve 190 to a state of non-contact with valve 190, the pressure P2 increases by an amount corresponding to the effects of F1 and P1. Therefore, setting F1 to a large value results in a large increase in pressure, thereby making the pressure in the second pressure control chamber 152 closer to the pressure in the first pressure control chamber 122. When F1 is sufficiently large, the pressure in the second pressure control chamber 152 becomes equal to the pressure in the first pressure control chamber 122 when the pressing plate 210 changes to a state of non-contact with valve 190 or during the process of changing from a contact state to a non-contact state. That is, making the spring force F1 of valve spring 200 relatively large can make the time spent stopping the cycle relatively short.

[0132] Next, we will use Figures 7A to 7C The spring constants of valve spring 200 and pressure regulating spring 220 are described. F1 and F2 in Equation 2 above vary according to the displacement of the pressing plate 210 and the flexible member 230. When from... Figure 7B The state changes to Figure 7CIn the state of [condition], the pressing plate 210 and the flexible member 230 gradually shift in the direction in which the valve spring 200 and the pressure regulating spring 220 lengthen. Therefore, the spring force F1 of the valve spring 200 gradually decreases proportionally to its spring constant until the pressing plate 210 disengages from the valve 190. Furthermore, the spring force F2 of the pressure regulating spring 220 gradually decreases proportionally to its spring constant until the pressing plate 210 shifts to its maximum extent in the direction that increases the internal volume. In summary, when the spring constants of the valve spring 200 and the pressure regulating spring 220 are large, according to equations 2 and 4, the decrease in F1 and F2 is larger, and therefore the increase in P2 or P3 is larger. For the pressure P2 in the second pressure control chamber 152, increasing the spring constant increases the increase in P2, which corresponds to the amount of ink flowing into the second pressure control chamber 152. Therefore, this reduces the time required to equal the pressure P2 in the first pressure control chamber 122. That is, by making the spring constant of the valve spring 200 or pressure regulating spring 220 in the second pressure control chamber 152 greater than the spring constant of the valve spring 200 or pressure regulating spring 220 in the first pressure control chamber 122, the time spent on the stop cycle can be shortened. In other words, by making the bias pressure of the biasing member in the second pressure control chamber 152 for biasing the valve 190 to enter the closed state greater than the bias pressure in the first pressure control chamber 122, the time spent on the stop cycle can be shortened.

[0133] Figures 11A to 11D This is a diagram describing the pressure regulating unit. Figure 11A Is with Figure 7C The same diagram, Figure 11B Viewed from the direction of the arrow Figure 11A The arrow diagram. The pressure receiving area S3 discussed so far can be derived as the area of ​​a circle with a diameter D1. This embodiment has been described using a circular first pressure regulating unit 120 and a circular second pressure regulating unit 150. However, the shape of the pressure regulating unit is not limited to this example. For example, the shape can be a basically square, such as... Figure 11C As shown. Alternatively, the shape can be a basic rectangle, such as... Figure 11D As shown. The advantageous effects described in this embodiment can also be achieved similarly in other shapes not shown. Furthermore, the shapes of the first pressure regulating unit 120 and the second pressure regulating unit 150 can be different from each other.

[0134] Furthermore, this embodiment has been described using a diagram in which a helical spring is used as both the valve spring 200 and the pressure regulating spring 220. However, the valve spring 200 and the pressure regulating spring 220 in this embodiment are not limited to helical springs. Similar advantageous effects can be achieved using conical springs, leaf springs, etc.

[0135] Furthermore, this embodiment has been described using an example in which the first pressure regulating unit 120 and the second pressure regulating unit 150 have valves respectively disposed in the first valve chamber 121 and the second valve chamber 151. However, the construction is not limited to this example.

[0136] Figure 12A and 12B This is a diagram illustrating another example of a pressure control unit. (As shown) Figure 12A and 12B As shown, a similar advantageous effect can also be achieved by arranging the valve in the first pressure control chamber 122 (or the second pressure control chamber 152) instead of in the valve chamber. Figure 12A This diagram shows that the connection port 191 is in the closed state. Figure 12B This diagram shows the connection port 191 in the open state. From... Figure 12A The off state is changed to Figure 12B In the open state, the pressing plate 210 and the flexible member 230 are displaced in a direction that reduces the internal volume of the first pressure control chamber 122 or the second pressure control chamber 152. This displacement causes the pressing plate 210 to abut against the valve 190, which then displaces to pivot about the rotation axis 250, thereby opening the communication port 191. As a result, the first valve chamber 121 (or the second valve chamber 151) and the first pressure control chamber 122 (or the second pressure control chamber 152) are in communication with each other. This configuration also achieves the advantageous effect of shortening the time spent on the stop cycle as described above. Furthermore, both the first pressure regulating unit 120 and the second pressure regulating unit 150 may have… Figure 12A and 12B The construction of, or only one of them may have Figure 12A and 12B The structure.

[0137] <Variations on loop paths>

[0138] In the above example, the first pressure control chamber 122 of the first pressure regulating unit 120 is connected to the outlet channel 180 of the circulation pump 500, and the second pressure control chamber 152 of the second pressure regulating unit 150 is connected to the inlet channel 170 of the circulation pump 500. That is, the circulation pump 500 has been described as being connected to both the supply channel 130 and the collection channel 140. Furthermore, an example has been described in which the first pressure control chamber 122 of the first pressure regulating unit 120 is connected to the second valve chamber 151 of the second pressure regulating unit 150 via the supply channel 130 and a bypass channel 160 communicating with the supply channel 130. Additionally, an example has been described in which the first pressure control chamber 122 of the first pressure regulating unit 120 is connected to the second valve chamber 151 of the second pressure regulating unit 150 via the bypass channel 160 but not via the supply channel 130.

[0139] The following will use Figures 13 to 16 A variant example describing a loop path. Figures 13 to 16 These are diagrams illustrating various variations of the circulation path. The circulation pump 500 can be connected to the supply channel 130 or the collection channel 140. Furthermore, the circulation pump 500 can be located outside the liquid injection head 1.

[0140] Figure 13 It is a schematic diagram illustrating the loop path. Figure 13 This illustrates an example where the pump outlet passage 180, located downstream of the circulation pump 500, is configured to connect to the ink tank 2 rather than to the first pressure control chamber 122. In other words, the circulation pump 500 is not connected to the supply passage 130.

[0141] Figure 14 It is a schematic diagram illustrating the loop path. Figure 14 This illustrates an example where the circulation pump 500, installed in the liquid injection head 1, is located outside the liquid injection head 1. Specifically, Figure 14 This illustrates an example where the circulating pump 500 is installed on the main body side of the liquid injection device 50. This configuration also causes the pump inlet passage 170 and the pump outlet passage 180 to be partially arranged outside the liquid injection head 1.

[0142] Figure 15 This is a schematic diagram illustrating a loop path. Figure 15In this process, ink supplied from ink tank 2 via external pump 21 and filter 110 is supplied to the valve chambers of the first pressure regulating unit 120 and the second pressure regulating unit 150. Note that no bypass channel 160 is provided. The ink supplied to the valve chambers is then supplied to the first pressure control chamber 122 and the second pressure control chamber 152, respectively. Subsequently, the ink supplied to the first pressure control chamber 122 is guided to the circulation pump 500-1 through the second supply channel 201, the first common channel 203, and the second collection channel 205, and is finally collected in ink tank 2. Similarly, the ink supplied to the second pressure control chamber 152 is guided to the circulation pump 500-2 through the third supply channel 202, the second common channel 204, and the third collection channel 206, and is finally collected in ink tank 2. The ink from circulation pumps 500-1 and 500-2 merges as they flow towards ink tank 2 and is then delivered to ink tank 2. The first common channel 203 and the second common channel 204 are channels formed within the injection module 300 and communicate with each other through the injection port 13. Therefore, a similar ink circulation occurs from the first common channel 203 to the second common channel 204 according to the pressure in the first pressure control chamber 122 and the second pressure control chamber 152. Similarly, in this configuration, the operation from stopping the circulation pumps 500-1 and 500-2 until the circulation stops is similar. Therefore, the advantageous effect of shortening the time spent stopping the circulation, as described in this embodiment, can also be achieved. In this example, the circulation pump 500 is not connected to the supply channel but to the collection channel.

[0143] Figure 16 It is a schematic diagram illustrating the loop path. Figure 16 express Figure 15 Further modifications. With Figure 15 Compared to its structure, Figure 16 The configuration allows for the presence of a single circulation pump 500, but omits the third collection channel 206. Similarly, in this configuration, the operation from when the circulation pump 500 stops until circulation stops is similar. Therefore, the advantageous effect of shortening the time spent stopping the cycle, as described in this embodiment, can also be achieved. Also in this example, the circulation pump 500 is connected to the collection channel instead of the supply channel. Note that... Figure 15 and 16 An example is shown where one or more circulation pumps 500 are installed on the main body side of the liquid jetting device 50, but the one or more circulation pumps may be installed inside the liquid jetting head 1.

[0144] Furthermore, while an example of a liquid jetting device 50 has been described so far using a serial scanning inkjet printer, similar advantageous effects can also be obtained for a linear inkjet printer.

[0145] As described above, according to this embodiment, the time spent stopping ink circulation after stopping the drive circulation pump 500 can be shortened.

[0146] <Reference Example>

[0147] A more detailed reference example of the above-described liquid jetting device will be described below. The reference example described below uses... Figure 5 and 6 A detailed example of a loop path is shown.

[0148] <Ink is supplied from both sides of the pressure chamber>

[0149] As described above, in this embodiment, an example has been used in which the connection port 191B in the second pressure regulating unit 150 is switched to an open state when ink is circulated by the driving circulation pump 500, and switched to a closed state when ink circulation stops. The controlled pressure can be set such that the connection port 191B in the second pressure regulating unit 150 remains closed even when ink is circulated by the driving circulation pump 500. This will be referred to below. Figure 5 The functions of bypass channel 160 will be described in detail.

[0150] The bypass channel 160 connecting the first pressure regulating unit 120 and the second pressure regulating unit 150 is configured so that, for example, if the negative pressure generated inside the circulation path becomes stronger than a preset value, the injection module 300 can avoid the effects of strong negative pressure. The bypass channel 160 is also configured to supply ink to the pressure chamber 12 from both the supply channel 130 and the collection channel 140.

[0151] First, an example will be described to avoid the effect of negative pressure becoming stronger than a preset value on the ejection module 300 by setting the bypass channel 160. For example, changes in ambient temperature can sometimes alter the properties of ink (e.g., viscosity). As the ink viscosity changes, the pressure loss within the circulation path also changes. For example, as the ink viscosity decreases, the amount of pressure loss within the circulation path decreases. As a result, the flow rate of the circulation pump 500, driven at a constant drive, increases, and the flow rate through the ejection module 300 increases. Here, the ejection module 300 is maintained at a constant temperature by a temperature regulating mechanism (not shown). Therefore, even if the ambient temperature changes, the viscosity of the ink within the ejection module 300 remains constant. With the ink viscosity within the ejection module 300 remaining constant, and the flow rate of the ink through the ejection module 300 increasing, the negative pressure in the ejection module 300 becomes correspondingly stronger due to flow resistance. If, as described above, the negative pressure in the ejection module 300 becomes stronger than a preset value, there is a possibility that the meniscus in the ejection port 13 may rupture and surrounding air may be drawn into the circulation path, which could lead to the inability to perform normal ejection. Moreover, even if the crescent does not rupture, there is still a possibility that the negative pressure in pressure chamber 12 will become stronger than the predetermined level and affect the jetting.

[0152] For these reasons, in this embodiment, a bypass channel 160 is formed in the circulation path. By providing the bypass channel 160, ink flows through the bypass channel 160 when the negative pressure is stronger than a preset value. Therefore, the pressure in the ejection module 300 remains constant. Thus, for example, the controlled pressure can be set such that even when the circulation pump 500 is driven, the connection port 191B in the second pressure regulating unit 150 remains closed. Furthermore, the controlled pressure in the second pressure regulating unit 150 can be set such that when the negative pressure becomes stronger than a preset value, the connection port 191B in the second pressure regulating unit 150 opens. In other words, even if the pump flow rate changes due to viscosity changes caused by environmental changes, as long as the meniscus does not collapse or the predetermined negative pressure is maintained, the connection port 191B can remain closed when the circulation pump 500 is driven.

[0153] Next, an example in which a bypass channel 160 is provided to supply ink to the pressure chamber 12 from both the supply channel 130 and the collection channel 140 will be described. The pressure in the circulation path may fluctuate due to the ejection operation of the ejection element 15. This is because the ejection operation generates a force that draws ink into the pressure chamber.

[0154] The following describes the fact that ink to be supplied to pressure chamber 12 is supplied from both the supply channel 130 side and the collection channel 140 side while continuing high duty cycle printing. Although the definition of "duty" can vary depending on various conditions, in the following text, the state of printing 1200 dpi grid cells with a single 4pl ink droplet will be considered as 100%. "High duty cycle printing" is, for example, printing performed at a 100% duty cycle.

[0155] While printing at a high duty cycle continues, the amount of ink flowing from pressure chamber 12 into the second pressure control chamber 152 through collection channel 140 decreases. On the other hand, circulation pump 500 causes ink to flow out at a constant rate. This disrupts the balance between the inflow into and outflow from the second pressure control chamber 152. Consequently, the amount of ink in the second pressure control chamber 152 decreases, and the negative pressure in the second pressure control chamber 152 becomes stronger, causing the second pressure control chamber 152 to contract. As the negative pressure in the second pressure control chamber 152 becomes stronger, the amount of ink flowing into the second pressure control chamber 152 through bypass channel 160 increases, and the second pressure control chamber 152 stabilizes in a state of balance between inflow and outflow. Therefore, the negative pressure in the second pressure control chamber 152 increases according to the duty cycle. Furthermore, as described above, in a configuration where the connection port 191B is closed when circulation pump 500 is driven, the connection port 191B changes to an open state according to the duty cycle, causing ink to flow into the second pressure control chamber 152 from bypass channel 160.

[0156] Furthermore, as high duty cycle printing continues, the inflow from pressure chamber 12 into the second pressure control chamber 152 via collection channel 140 decreases, while the inflow from connector 191B into the second pressure control chamber 152 via bypass channel 160 increases. As this state progresses further, the amount of ink flowing from pressure chamber 12 into the second pressure control chamber 152 via collection channel 140 reaches zero, such that the ink flowing out of connector 191B is all the ink that has flowed out of circulation pump 500. As this state progresses further, ink flows back from the second pressure control chamber 152 into pressure chamber 12 via collection channel 140. In this state, ink flowing from the second pressure control chamber 152 into circulation pump 500 and ink flowing from the second pressure control chamber 152 into pressure chamber 12 will flow into the second pressure control chamber 152 via bypass channel 160 from connector 191B. In this case, ink from supply channel 130 and ink from collection channel 140 are filled into pressure chamber 12 and ejected from it.

[0157] Note that this ink backflow occurring at high print duty cycles is a phenomenon caused by the installation of the bypass channel 160. Furthermore, as described above, an example has been given of changing the connection port 191B in the second pressure regulating unit to an open state to allow ink backflow. However, ink backflow may also occur when the connection port 191B in the second pressure regulating unit is open. Moreover, in a configuration without a second pressure regulating unit, the aforementioned ink backflow can also occur by installing the bypass channel 160. Incidentally, it is sufficient for the bypass channel 160 to allow communication between at least one of the first channel or the first pressure regulating unit 120 and the second channel without a pressure chamber 12 between them.

[0158] <Construction of the jet unit>

[0159] Figure 17A and 17B This is a schematic diagram showing the circulation path of ink for one color in the spray unit 3 of this embodiment. Figure 17A This is an exploded perspective view of the injection unit 3 as seen from the side of the first support member 4. Figure 17B This is an exploded perspective view of the injection unit 3 as seen from the side of the injection module 300. Note that... Figure 17A and 17B The arrows labeled "IN" and "OUT" indicate ink flow, and the ink flow will only be described for one color, but other colors of ink flow similarly. Furthermore, in Figure 17A and 17B The illustrations of the second support member 7 and the electrical wiring member 5 are omitted, and their descriptions are also omitted in the following description of the construction of the injection unit. Furthermore, for Figure 17A The first support member 4 in the middle shows along Figure 3A The cross-section of line XVII-XVII in the middle. Each spray module 300 includes a spray element substrate 340 and an opening plate 330. Figure 18 This is a view showing the opening plate 330. Figure 19 This is a view showing the jetting element substrate 340.

[0160] Ink is supplied from each circulation unit 54 to the ejection unit 3 via the connecting member 8 (see...). Figure 3A The ink path for returning the ink to the joining member 8 after it has passed through the joining member 8 will now be described. Additionally, the joining member 8 is omitted from the figures mentioned below.

[0161] Each ejection module 300 includes an ejection element substrate 340 and an aperture plate 330 (which are silicon substrates 310), and also includes an outlet forming member 320. The ejection element substrate 340, the aperture plate 330, and the outlet forming member 320 are stacked and joined such that the channels of each ink are interconnected to form the ejection module 300. The ejection module 300 is supported on a first support member 4. The ejection unit 3 is formed by supporting each ejection module 300 on the first support member 4. The ejection element substrate 340 includes an outlet forming member 320, which includes a plurality of outlet columns, each outlet column being a plurality of outlets 13 forming a row. A portion of the ink supplied through the ink channels in the ejection module 300 is ejected from the ejection outlets 13. Unejected ink is collected through the ink channels in the ejection module 300.

[0162] like Figure 17A and 17B as well as Figure 18 As shown, the opening plate 330 includes a plurality of ink supply ports 311 arranged in a row and a plurality of ink collection ports 312 arranged in a row. For example... Figure 19 and Figures 20A to 20C As shown, the jetting element substrate 340 includes a plurality of arranged supply connection channels 323 and a plurality of arranged collection connection channels 324. The jetting element substrate 340 also includes a common supply channel 18 communicating with the plurality of supply connection channels 323 and a common collection channel 19 communicating with the plurality of collection connection channels 324. The ink supply channel 48 and ink collection channel 49 are arranged in the first support member 4 (see...). Figure 3A and 3B The support member supply port 211 is a cross-sectional opening that forms the ink supply channel 48. The support member collection port 212 is a cross-sectional opening that forms the ink collection channel 49.

[0163] The ink supplied to the jetting unit 3 is from the circulation unit 54 (see...) Figure 3A The ink supply channel 48 (see) supplies ink to the first support member 4 from the side. Figure 3A Ink flowing through the support member supply port 211 in the ink supply channel 48 passes through the ink supply channel 48 (see ink supply channel 48). Figure 3A The ink supply port 311 in the opening plate 330 is supplied to the common supply channel 18 in the jet element substrate 340 and enters the supply connection channel 323. Up to this point, the channel is a supply-side channel. Thereafter, ink forms the pressure chamber 12 in the member 320 through the discharge port (see...). Figure 3B And it flows into the collection connection channel 324 of the collection side channel. The details of the ink flow in the pressure chamber 12 will be described below.

[0164] In the collection side channel, ink entering the collection connection channel 324 flows into the common collection channel 19. Thereafter, ink flows from the common collection channel 19 into the ink collection channel 49 in the first support member 4 through the ink collection port 312 in the opening plate 330, and is collected into the circulation unit 54 through the support member collection port 212.

[0165] The areas of the opening plate 330 where neither the ink supply port 311 nor the ink collection port 312 exists correspond to the areas of the first support member 4 used to separate the support member supply port 211 and the support member collection port 212. Furthermore, the first support member 4 does not have openings in these areas. When the inkjet module 300 and the first support member 4 are combined, these areas serve as the joining areas.

[0166] exist Figure 18 In the opening plate 330, multiple rows of openings arranged along the X direction are arranged side-by-side in the Y direction, and openings for supply (IN) and openings for collection (OUT) are alternately arranged in the Y direction while being offset from each other by half a pitch in the X direction. Figure 19 In the jetting element substrate 340, a common supply channel 18 communicating with a plurality of supply connection channels 323 arranged along the Y direction and a common collection channel 19 communicating with a plurality of collection connection channels 324 arranged along the Y direction are alternately arranged in the X direction. The common supply channel 18 and the common collection channel 19 are separated according to the ink type. Furthermore, the number of jetting nozzle rows for each color determines the number of common supply channels 18 and common collection channels 19 to be arranged. Additionally, the number of arranged supply connection channels 323 and the number of arranged collection connection channels 324 correspond to the number of jetting nozzles 13. Note that a one-to-one correspondence is not mandatory; a single supply connection channel 323 and a single collection connection channel 324 can correspond to multiple jetting nozzles 13.

[0167] Each jetting module 300 is formed by stacking and joining the opening plate 330 and the jetting element substrate 340 as described above so that the channels of each ink are connected to each other, and is supported on the first support member 4. As a result, an ink channel including the supply channel and the collection channel as described above is formed.

[0168] Figures 20A to 20C This is a cross-sectional view showing the ink flow at different parts of the jetting unit 3. Figure 20A It is along Figure 17A The cross-section taken by line XXA-XXA shows the cross-section of the following part of the injection unit 3, in which the ink supply channel 48 and the ink supply port 311 are connected to each other. Figure 20B It is along Figure 17AThe cross-section taken by line XXB-XXB shows a portion of the jetting unit 3 where the ink collection channel 49 and the ink collection port 312 are connected to each other. Furthermore, Figure 20C It is along Figure 17A The cross-section taken by line XXC-XXC shows the portion of the ink supply port 311 and ink collection port 312 that is not connected to the channel in the first support member 4.

[0169] like Figure 20A As shown, the ink supply channel supplies ink from the portion where the ink supply channel 48 in the first support member 4 overlaps and communicates with the ink supply port 311 in the opening plate 330. Furthermore, as... Figure 20B As shown, the ink collection channel collects ink from the portion where the ink collection channel 49 in the first support member 4 overlaps and communicates with the ink collection port 312 in the opening plate 330. Furthermore, as... Figure 20C As shown, the jetting unit 3 partially has areas where no openings are provided in the opening plate 330. In these areas, ink is neither supplied nor collected between the jetting element substrate 340 and the first support member 4. Ink is supplied at the areas where ink supply ports 311 are provided, such as... Figure 20A As shown. Figure 20B As shown, ink is collected in the area where the ink collection port 312 is provided. Note that this embodiment has been described as an example using a configuration with an opening plate 330, but a configuration without the opening plate 330 can be used. For example, a configuration can be used in which: channels corresponding to the ink supply channel 48 and the ink collection channel 49 are formed in the first support member 4, and the jetting element substrate 340 is bonded to the first support member 4.

[0170] Figure 21A and 21B This is a cross-sectional view showing the vicinity of the injection port 13 in the injection module 300. Additionally, Figure 21A and Figure 21B The thick arrows shown in the common supply channel 18 and common collection channel 19 indicate the oscillating motion of ink generated in the configuration using the serial liquid jetting device 50. Ink supplied to the pressure chamber 12 via the common supply channel 18 and supply connection channel 323 is ejected from the jet nozzle 13 as the jetting element 15 is driven. When the jetting element 15 is not driven, the ink is collected from the pressure chamber 12 into the common collection channel 19 via the collection connection channel 324, which serves as a collection channel.

[0171] When using a serial liquid jetting device 50 to jet ink in the above-mentioned cycle, ink jetting is significantly affected by the ink oscillation within the ink channels caused by the main scan of the liquid jetting head 1. Specifically, the oscillation of ink within the ink channels manifests as differences in the amount of ink jetted and deviations in the jetting direction. When the common supply channel 18 and common collection channel 19 have a wider cross-sectional shape in the X direction, which is the main scan direction, the ink within these channels is more susceptible to inertial forces in the main scan direction, causing significant ink oscillation. This oscillation can potentially affect the likelihood of ink being ejected from the jetting nozzle 13. Furthermore, widening the common supply channel 18 and common collection channel 19 in the X direction increases the distance between colors. This reduces printing efficiency.

[0172] Therefore, in this embodiment, each public supply channel 18 and each public collection channel 19 (whose cross-section is in...) Figure 21A and 21B (As shown in the diagram) It has a configuration in which each common supply channel 18 and each common collection channel 19 extends along the Y direction and also along the Z direction, which is perpendicular to the X direction, which is the main scanning direction. With this configuration, the common supply channel 18 and the common collection channel 19 are given a small channel width in the main scanning direction. By giving the common supply channel 18 and the common collection channel 19 a small channel width in the main scanning direction, during the main scan, due to the inertial force acting on the ink and applied in the direction opposite to the main scanning direction (…),… Figure 21A and 21B The ink oscillation motion within the common supply channel 18 and common collection channel 19 (as indicated by the thick black arrow in the image) is reduced. This decreases the impact of ink oscillation motion on ink ejection. Furthermore, by extending the common supply channel 18 and common collection channel 19 in the Z direction, their cross-sectional area is increased. This reduces the channel pressure drop.

[0173] As described above, each common supply channel 18 and each common collection channel 19 is given a small channel width in the main scanning direction. This configuration reduces the oscillating motion of ink within the common supply channel 18 and common collection channel 19 during the main scan, but does not eliminate the oscillating motion. Therefore, in this embodiment, in order to reduce the jetting differences between ink types that may also result from the reduced oscillating motion, the common supply channel 18 and common collection channel 19 are arranged to overlap each other in the X direction.

[0174] As described above, in this embodiment, the supply connection channel 323 and the collection connection channel 324 are provided correspondingly to the ejection port 13. Furthermore, the correspondence between the supply connection channel 323 and the collection connection channel 324 is established such that the supply connection channel 323 and the collection connection channel 324 are arranged along the X-direction with the ejection port 13 inserted between them. Therefore, if the common supply channel 18 and the common collection channel 19 have portions in which the common supply channel 18 and the common collection channel 19 do not overlap with each other in the X-direction, the correspondence between the supply connection channel 323 and the collection connection channel 324 in the X-direction is disrupted. This mismatch affects the ink flow and ink ejection in the pressure chamber 12 along the X-direction. If this mismatch is combined with the effect of the oscillating motion of the ink, there is a possibility that it may further affect the ink ejection from each ejection port.

[0175] Therefore, by arranging the common supply channel 18 and the common collection channel 19 at positions that overlap each other in the X direction, the oscillating motion of the ink within the common supply channel 18 and the common collection channel 19 is substantially the same at any position in the Y direction along the arrangement of the ejector nozzles 13 during the main scan. Consequently, the pressure difference generated in the pressure chamber 12 between the common supply channel 18 side and the common collection channel 19 side does not vary significantly. These low pressure differences enable stable ejection.

[0176] Furthermore, some liquid jet heads that circulate ink are configured such that the channel for supplying ink to the liquid jet head and the channel for collecting ink are the same channel. However, in this embodiment, the common supply channel 18 and the common collection channel 19 are different channels. Additionally, the supply connection channel 323 and the pressure chamber 12 are in communication with each other, the pressure chamber 12 and the collection connection channel 324 are in communication with each other, and ink is ejected from the ejection port 13 in the pressure chamber 12. That is, a configuration is formed such that the pressure chamber 12, which serves as the path connecting the supply connection channel 323 and the collection connection channel 324, includes the ejection port 13. Therefore, in each pressure chamber 12, an ink flow is generated from the supply connection channel 323 side to the collection connection channel 324 side, and the ink within the pressure chamber 12 is effectively circulated. By effectively circulating the ink within the pressure chamber 12, the ink within the pressure chamber 12, which is susceptible to ink evaporation from the ejection port 13, remains fresh.

[0177] Furthermore, since two channels (i.e., common supply channel 18 and common collection channel 19) are connected to the pressure chamber 12, ink can be supplied from both channels when high-flow-rate jetting is required. That is, compared to a configuration that forms only a single channel for ink supply and collection, the configuration in this embodiment has the advantage of not only being able to perform efficient circulation but also being able to handle high-flow-rate jetting.

[0178] Incidentally, when the common supply channel 18 and the common collection channel 19 are arranged close to each other in the X direction, the effect of the ink's oscillating motion is smaller. The common supply channel 18 and the common collection channel 19 are ideally arranged such that the gap between the channels is 75 μm to 100 μm.

[0179] Ink that has received heat from the jetting element 15 in the pressure chamber 12 flows into the common collection channel 19. Therefore, the temperature of the ink flowing through the common collection channel 19 is higher than the temperature of the ink in the common supply channel 18. Here, if only the common collection channel 19 exists in a portion of the jetting element substrate 340 in the X direction, the temperature in that portion may locally increase, resulting in temperature non-uniformity within the jetting module 300. This temperature non-uniformity affects jetting.

[0180] The temperature of the ink flowing through the common supply channel 18 is lower than the temperature of the ink in the common collection channel 19. Therefore, if the common supply channel 18 and the common collection channel 19 are close to each other, the ink in the relatively cooler common supply channel 18 lowers the ink temperature in the common collection channel 19 at the point where the two channels are close together. This suppresses temperature rise. Therefore, it is preferable that the common supply channel 18 and the common collection channel 19 have substantially the same length, exist at a position where they overlap in the X direction, and are close to each other.

[0181] Figure 22A and 22B This is a view showing the channel structure of a liquid ejector head 1 for printing inks of three colors: cyan (C), magenta (M), and yellow (Y). In the liquid ejector head 1, as... Figure 22A As shown, a circulation channel is set up for each ink type. The pressure chamber 12 is set along the X direction, which is the main scanning direction of the liquid jet head 1. Furthermore, as... Figure 22B As shown, a common supply channel 18 and a common collection channel 19 are arranged along the nozzle array (which is an array of nozzles 13). The common supply channel 18 and the common collection channel 19 are arranged to extend in the Y direction, with the nozzle array located between them.

[0182] <Connection between the main unit and the liquid injection head>

[0183] Figure 23This is a schematic structural diagram showing more specifically the connection between the ink tank 2 and the external pump 21, which are the main units of the liquid jetting device 50 in this embodiment, and the liquid jetting head 1, as well as the arrangement of the circulation pump, etc. The liquid jetting device 50 in this embodiment is configured such that, in the event of a malfunction in the liquid jetting head 1, only the liquid jetting head 1 can be easily replaced. Specifically, the liquid jetting device 50 in this embodiment has a liquid connection 700, through which the liquid jetting head 1 and each ink supply pipe 59 connected to the corresponding external pump 21 can be easily connected and disconnected from each other. This allows for easy attachment and removal of only the liquid jetting head 1 from the liquid jetting device 50.

[0184] like Figure 23 As shown, each liquid connection 700 has a liquid connector insertion slot 53a protrudingly disposed on the head housing 53 of the liquid ejector head 1, and a cylindrical liquid connector 59a into which the liquid connector insertion slot 53a can be inserted. The liquid connector insertion slot 53a is fluidly connected to an ink supply channel formed in the liquid ejector head 1 and is connected to the first pressure regulating unit 120 via the aforementioned filter 110. The liquid connector 59a is disposed at the end of an ink supply pipe 59 connected to an external pump 21, which supplies ink from the ink tank 2 to the liquid ejector head 1 by pressurization.

[0185] As mentioned above, Figure 23 The liquid injection head 1 shown has a liquid connection portion 700. This facilitates the attachment, removal, and replacement of the liquid injection head 1. However, in the event of a deterioration in the sealing performance between the liquid connector insertion slot 53a and the liquid connector 59a, there is a possibility that ink supplied under pressure by the external pump 21 may leak from the liquid connection portion 700. If the leaked ink adheres to the circulation pump 500, for example, it may cause a malfunction in the electrical system. To solve this problem, in this embodiment, the circulation pump, etc., is arranged as follows.

[0186] Arrangement of circulating pumps, etc.

[0187] like Figure 23As shown, in this embodiment, to prevent ink leaking from the liquid connection 700 from adhering to the circulation pump 500, the circulation pump 500 is arranged higher than the liquid connection 700 in the direction of gravity. Specifically, the circulation pump 500 is arranged higher than the liquid connector insertion slot 53a, which serves as the liquid inlet in the liquid jet head 1, in the direction of gravity. Furthermore, the circulation pump 500 is arranged at a position that does not contact the constituent components of the liquid connection 700. In this way, even if ink leaks from the liquid connection 700, the ink will flow in the horizontal direction (i.e., the opening direction of the opening of the liquid connector 59a) or downward in the direction of gravity. This prevents ink from reaching the circulation pump 500, which is located at a higher position in the direction of gravity. In addition, arranging the circulation pump 500 at a position separate from the liquid connection 700 also reduces the possibility of ink reaching the circulation pump 500 through the components.

[0188] Furthermore, the electrical connection portion 515, which connects the circulation pump 500 and the electrical contact substrate 6 via the flexible wiring member 514, is positioned higher than the liquid connection portion 700 in the direction of gravity. This reduces the likelihood of ink from the liquid connection portion 700 causing electrical malfunctions.

[0189] Furthermore, in this embodiment, a wall portion 53b is provided in the head housing 53. Therefore, even if ink is ejected from the opening 59b of the liquid connection portion 700, the wall portion 53b blocks the ink, thereby reducing the possibility of the ink reaching the circulation pump 500 or the electrical connection portion 515.

[0190] <Circulation Pump>

[0191] Next, we will refer to Figure 24A and 24B as well as Figure 25 The construction and operation of each circulation pump 500 incorporated in the liquid injection head 1 are described in detail.

[0192] Figure 24A and 24B This is an external perspective view of the circulating pump 500. Figure 24A This is an external perspective view showing the front side of the circulating pump 500. Figure 24BThis is an external perspective view showing the rear side of the circulation pump 500. The housing of the circulation pump 500 includes a pump housing 505 and a cover 507 fixed to the pump housing 505. The pump housing 505 includes a housing body 505a and a channel connecting member 505b adhesively fixed to the outer surface of the housing body 505a. In each of the housing body 505a and the channel connecting member 505b, a pair of through holes communicating with each other are formed at two different locations. One of the through holes in the pair of through holes, located at one location, forms a pump supply hole 501. The other through hole in the pair of through holes, located at the other location, forms a pump discharge hole 502. The pump supply hole 501 is connected to a pump inlet passage 170 connected to a second pressure control chamber 152. The pump discharge hole 502 is connected to a pump outlet passage 180 connected to a first pressure control chamber 122. Ink supplied from the pump supply hole 501 passes through a pump chamber 503, described later (see [link to relevant documentation]). Figure 25 ), and discharged from the pump discharge port 502.

[0193] Figure 25 yes Figure 24A The diagram shows a cross-sectional view of the circulating pump 500 along the XXV-XXV line. A diaphragm 506 is joined to the inner surface of the pump housing 505, and a pump chamber 503 is formed between the diaphragm 506 and a recess formed in the inner surface of the pump housing 505. The pump chamber 503 communicates with a pump supply port 501 and a pump discharge port 502 formed in the pump housing 505. Furthermore, a check valve 504a is provided at the middle portion of the pump supply port 501. A check valve 504b is provided at the middle portion of the pump discharge port 502. That is, the circulating pump 500 includes check valves located in the channels through which the second and third channels communicate with each other. Specifically, the check valve 504a is arranged such that a portion of it can be contained within the space 512a formed in the middle portion of the pump supply port 501. Figure 25 The check valve 504b is arranged such that a portion of it can move to the left within the space 512b formed in the middle portion of the pump discharge port 502. Figure 25 Move to the right in the middle.

[0194] As the diaphragm 506 shifts to increase the volume of the pump chamber 503, the pump chamber 503 is depressurized. In response to this shift, the check valve 504a separates from the opening of the pump supply port 501 in the space 512a (i.e., along...). Figure 25(Moving to the left in the middle). Check valve 504a changes to an open state, allowing ink flow through pump supply port 501, by separating from the opening of pump supply port 501 within space 512a. As diaphragm 506 shifts to reduce the volume of pump chamber 503, pump chamber 503 is pressurized. In response to this displacement, check valve 504a comes into close contact with the wall surface surrounding the opening of pump supply port 501. Check valve 504a is thus in a closed state, in which check valve 504a blocks ink flow through pump supply port 501.

[0195] On the other hand, as the pump chamber 503 depressurizes, the check valve 504b comes into close contact with the wall surface surrounding the opening in the pump housing 505, thereby changing to a closed state where the check valve 504b blocks ink flow through the pump discharge port 502. Furthermore, as the pump chamber 503 is pressurized, the check valve 504b separates from the opening in the pump housing 505 and moves toward the space 512b (i.e., along...). Figure 25 (Move to the right in the middle), thereby allowing ink to flow through the pump discharge hole 502.

[0196] Note that the material of each of check valves 504a and 504b only needs to be a material that can deform under pressure in pump chamber 503. For example, the material of each of check valves 504a and 504b can be formed of an elastic material, such as ethylene-propylene-diene methylene bond compound (EPDM) or elastomer, or a membrane or sheet of polypropylene, etc. However, the material is not limited to these.

[0197] As described above, the pump chamber 503 is formed by joining the pump housing 505 and the diaphragm 506. Therefore, the pressure in the pump chamber 503 changes as the diaphragm 506 deforms. For example, when the diaphragm 506 shifts towards the pump housing 505 (…), the pressure changes. Figure 25 When the pump chamber 503 is shifted to the right, resulting in a decrease in volume, the pressure inside the pump chamber 503 increases. As a result, the check valve 504b, which is positioned facing the pump discharge port 502, opens, allowing ink to be discharged from the pump chamber 503. At this time, the check valve 504a, which is positioned facing the pump supply port 501, comes into close contact with the wall surface surrounding the pump supply port 501, thereby preventing ink from flowing back from the pump chamber 503 into the pump supply port 501.

[0198] Conversely, when the diaphragm 506 shifts in the direction that widens the pump chamber 503, the pressure in the pump chamber 503 decreases. As a result, the check valve 504a, arranged facing the pump supply port 501, turns open, allowing ink to be supplied to the pump chamber 503. At this time, the check valve 504b arranged in the pump discharge port 502 comes into close contact with the wall surface surrounding the opening formed in the pump housing 505 to close the opening. This prevents ink from flowing back from the pump discharge port 502 into the pump chamber 503.

[0199] As described above, in the circulating pump 500, ink is drawn in and discharged as the diaphragm 506 deforms, thereby changing the pressure in the pump chamber 503. However, when air bubbles enter the pump chamber 503, the pressure change in the pump chamber 503 is relatively small due to the expansion or contraction of the bubbles and the displacement of the diaphragm 506. Therefore, the amount of liquid to be pumped is reduced. To address this issue, the pump chamber 503 is arranged parallel to gravity, allowing air bubbles that have entered the pump chamber 503 to easily accumulate at the top. Furthermore, the pump discharge port 502 is arranged above the center of the pump chamber 503. This improves the ease of air bubble discharge from the pump and thus stabilizes the flow rate.

[0200] Although this disclosure has been described with reference to exemplary embodiments, it should be understood that this disclosure is not limited to the disclosed exemplary embodiments. The scope of the following claims should be given the broadest interpretation to cover all such modifications and equivalent structures and functions.

Claims

1. A liquid injection head, comprising: The injection module includes a pressure chamber and an injection element configured to generate pressure for injecting liquid into the pressure chamber; A supply channel is connected to the pressure chamber, and liquid is supplied to the pressure chamber through the supply channel; A collection channel, which is connected to the pressure chamber and collects liquid from the pressure chamber through the collection channel; The first pressure regulating unit has the following features: The first pressure control chamber is connected to the supply channel. The first valve chamber is connected to the first pressure control chamber through a first opening, and A first valve is configured to open and close a first opening; The second pressure regulating unit has: The second pressure control chamber is connected to the collection channel. The second valve chamber is connected to the second pressure control chamber via a second opening, and The second valve is configured to open and close the second opening; and A circulating pump, which is configured to deliver liquid, The first pressure control chamber has: A first flexible member is disposed on the surface opposite to the first opening. The first pressing plate is configured to displace in conjunction with the first flexible member; and The first biasing member biases the first pressing plate in a direction that increases the volume of the first pressure control chamber. The first pressure control chamber is configured to open and close the first opening using a first valve based on the displacement of the first pressing plate and the first flexible member. The second pressure control chamber has the following features: The second flexible member is disposed on the surface opposite to the second opening. The second pressing plate is configured to displace in conjunction with the second flexible member, and The second biasing member biases the second pressing plate in the direction that increases the volume of the second pressure control chamber. The second pressure control chamber is configured to open and close the second opening using a second valve based on the displacement of the second pressing plate and the second flexible member. The controlled pressure in the first pressure regulating unit is set to be higher than the controlled pressure in the second pressure regulating unit, and Wherein, when the second opening is in the open state through the second valve, the pressure receiving area of ​​the second flexible member and the second pressing plate in the second pressure control chamber is smaller than the pressure receiving area of ​​the first flexible member and the first pressing plate in the first pressure control chamber when the first opening is in the open state through the first valve.

2. The liquid injection head according to claim 1, wherein, The projected area of ​​the movable portion of the second flexible member and the second pressing plate on the plane at the second opening in the second pressure control chamber is smaller than the projected area of ​​the movable portion of the first flexible member and the first pressing plate on the plane at the first opening in the first pressure control chamber.

3. The liquid injection head according to claim 1, wherein, The projected area of ​​the second pressing plate at the second opening in the second pressure control chamber is smaller than the projected area of ​​the first pressing plate at the first opening in the first pressure control chamber.

4. The liquid injection head according to claim 1, wherein, The second pressing plate of the second pressure control chamber can move away from the plane of the second opening in a direction perpendicular to the plane of the second opening by a smaller amount than the first pressing plate of the first pressure control chamber can move away from the plane of the first opening in a direction perpendicular to the plane of the first opening.

5. The liquid injection head according to any one of claims 1 to 4, wherein... The first valve is arranged in the first valve chamber or the second valve is arranged in the second valve chamber, or The first valve is arranged in the first valve chamber and the second valve is arranged in the second valve chamber.

6. The liquid injection head according to any one of claims 1 to 4, wherein The first valve is arranged in the first pressure control chamber or the second valve is arranged in the second pressure control chamber, or The first valve is located in the first pressure control chamber and the second valve is located in the second pressure control chamber.

7. The liquid injection head according to any one of claims 1 to 4, wherein... The first pressure control chamber is connected to the outlet channel of the circulating pump, and The second pressure control chamber is connected to the inlet channel of the circulating pump.

8. The liquid injection head according to any one of claims 1 to 4 further includes a bypass passage connecting the first pressure control chamber and the second valve chamber.

9. The liquid injection head according to any one of claims 1 to 4, wherein, The first pressure control chamber is connected to the second valve chamber, and there is no supply passage between the first pressure control chamber and the second valve chamber.

10. The liquid injection head according to any one of claims 1 to 4, wherein, The circulation pump is connected to the supply channel or the collection channel.

11. The liquid injection head according to any one of claims 1 to 4, wherein, The circulation pump is connected to both the supply channel and the collection channel.

12. The liquid injection head according to any one of claims 1 to 4, wherein, The circulation pump is located inside the liquid jet head.

13. A liquid injection head, comprising: The injection module includes a pressure chamber and an injection element configured to generate pressure for injecting liquid into the pressure chamber; A supply channel is connected to the pressure chamber, and liquid is supplied to the pressure chamber through the supply channel; A collection channel, which is connected to the pressure chamber and collects liquid from the pressure chamber through the collection channel; The first pressure regulating unit has the following features: The first pressure control chamber is connected to the supply channel. The first valve chamber is connected to the first pressure control chamber through a first opening, and A first valve is configured to open and close a first opening; The second pressure regulating unit has: The second pressure control chamber is connected to the collection channel. The second valve chamber is connected to the second pressure control chamber via a second opening, and The second valve is configured to open and close the second opening; and A circulating pump, which is configured to deliver liquid, The first pressure control chamber has: A first flexible member is disposed on the surface opposite to the first opening. The first pressing plate is configured to shift in conjunction with the first flexible member; and The first biasing member biases the first pressing plate in a direction that increases the volume of the first pressure control chamber. The first pressure control chamber is configured to open and close the first opening using a first valve based on the displacement of the first pressing plate and the first flexible member. The second pressure control chamber has the following features: The second flexible member is disposed on the surface opposite to the second opening. The second pressing plate is configured to shift in conjunction with the second flexible member, and The second biasing member biases the second pressing plate in the direction that increases the volume of the second pressure control chamber. The second pressure control chamber is configured to open and close the second opening using a second valve based on the displacement of the second pressing plate and the second flexible member. The controlled pressure in the first pressure regulating unit is set to be higher than the controlled pressure in the second pressure regulating unit, and Among them, the biasing force of the second biasing member is greater than the biasing force of the first biasing member.

14. The liquid injection head according to claim 13, wherein, The spring constant of the second biasing component is greater than the spring constant of the first biasing component.

15. The liquid injection head according to claim 13 or 14, wherein... The first valve is arranged in the first valve chamber or the second valve is arranged in the second valve chamber, or The first valve is arranged in the first valve chamber and the second valve is arranged in the second valve chamber.

16. The liquid injection head according to claim 13 or 14, wherein... The first valve is arranged in the first pressure control chamber or the second valve is arranged in the second pressure control chamber, or The first valve is located in the first pressure control chamber and the second valve is located in the second pressure control chamber.

17. The liquid injection head according to claim 13 or 14, wherein... The first pressure control chamber is connected to the outlet channel of the circulating pump, and The second pressure control chamber is connected to the inlet channel of the circulating pump.

18. The liquid injection head according to claim 13 or 14, further comprising a bypass passage connecting the first pressure control chamber and the second valve chamber.

19. The liquid injection head according to claim 13 or 14, wherein, The first pressure control chamber is connected to the second valve chamber, and there is no supply passage between the first pressure control chamber and the second valve chamber.

20. The liquid injection head according to claim 13 or 14, wherein, The circulation pump is connected to the supply channel or the collection channel.

21. The liquid injection head according to claim 13 or 14, wherein, The circulation pump is connected to both the supply channel and the collection channel.

22. The liquid injection head according to claim 13 or 14, wherein, The circulation pump is located inside the liquid jet head.

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