Liquid jet head and liquid jetting equipment

Abstract

This invention provides a liquid injection head and a liquid injection device that suppress injection failures without increasing device size. To this end, a flow path is provided between a circulation unit and a supply flow path communicating with a pressure chamber. The vertical cross-sectional area of ​​this flow path in the liquid circulation direction is two or more times that of the vertical cross-sectional area of ​​the supply flow path in the liquid circulation direction. Furthermore, the flow path has an inner wall inclined relative to the direction of gravity, and the component of the normal vector of this inner wall has a component in the direction of gravity.

Description

[0001] This application is a divisional application of Chinese patent application No. 202310545275.2, filed on May 15, 2023, entitled "Liquid Jetting Head and Liquid Jetting Device". Technical Field

[0002] This invention relates to a liquid jetting head and a liquid jetting device. Background Technology

[0003] Japanese Patent Application Publication No. 2003-312006 discloses a liquid jet head in which a fluid reservoir, a pump, a circulation path and a print head are arranged on a bracket, the pump circulates the fluid in the circulation path, and during the printing cycle, the fluid is supplied from the fluid reservoir to the print head.

[0004] However, the liquid ejector head in Japanese Patent Application Publication No. 2003-312006 has a separator structure for separating gas and liquid and an air escape area, which raises concerns about increased ejector head size and ink solidification in the separator structure. Furthermore, while air bubbles are guided to the gas-liquid separator structure by tilting the inside of the circulation path, this circulation path does not pass through the pressure chamber of the nozzle containing the fluid in the printhead. In other words, in the liquid ejector head of Japanese Patent Application Publication No. 2003-312006, there is no fluid circulation in the pressure chamber, which raises concerns about ejection malfunctions if air bubbles or the like enter the pressure chamber. Summary of the Invention

[0005] Therefore, the present invention provides a liquid jet head and a liquid jetting device that suppress the occurrence of jetting failures without increasing the size of the equipment.

[0006] Therefore, the liquid jetting head of the present invention includes: a printing element substrate having a pressure chamber in which a jetting port is formed, and liquid is jetted from the jetting port; a first supply flow path disposed on the printing element substrate and communicating with the pressure chamber; a first collection flow path disposed on the printing element substrate and communicating with the pressure chamber; a circulation pump that creates a pressure difference between the first supply flow path and the first collection flow path, such that liquid is supplied from the first supply flow path to the pressure chamber and liquid in the pressure chamber is collected from the first collection flow path; and a second supply flow path connecting the first supply flow path and the circulation pump, wherein the vertical cross-sectional area of ​​the second supply flow path in the liquid circulation direction is two or more times that of the vertical cross-sectional area of ​​the first supply flow path in the liquid circulation direction, and has an inner wall of the flow path inclined relative to the direction of gravity, and the component of the normal vector of the inner wall of the flow path has a component in the direction of gravity.

[0007] According to the present invention, a liquid jet head and a liquid jetting device can be provided that suppress the occurrence of jetting failures without increasing the size of the device.

[0008] Other features of the invention will become apparent from the following description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0009] Figure 1 It is a schematic perspective view of a liquid jetting device that can utilize liquid jetting heads;

[0010] Figure 2 It is a 3D view of the liquid injection head;

[0011] Figure 3 This is an exploded 3D view of the liquid injection head;

[0012] Figure 4 It is a schematic diagram showing the circulation path of an ink of a certain color under constant conditions;

[0013] Figure 5A These are cross-sectional views taken at different locations along the Y direction on the printed component substrate.

[0014] Figure 5B These are cross-sectional views taken at different locations along the Y direction on the printed component substrate.

[0015] Figure 5C These are cross-sectional views taken at different locations along the Y direction on the printed component substrate.

[0016] Figure 6 This illustrates the ink flow when printing is performed using multiple jet ports;

[0017] Figure 7 This is a side view showing the liquid injection head;

[0018] Figure 8A This is a cross-sectional view showing the liquid injection head;

[0019] Figure 8B This is a cross-sectional view showing the liquid injection head;

[0020] Figure 9 This is a schematic diagram showing the internal structure of a loop unit in an understandable way;

[0021] Figure 10A It is a cross-sectional view showing the first ink connection flow path and the second ink connection flow path;

[0022] Figure 10B This is a cross-sectional view showing the first ink connection flow path and the second ink connection flow path;

[0023] Figure 10C This is a cross-sectional view showing the first ink connection flow path and the second ink connection flow path;

[0024] Figure 11A This is a cross-sectional view showing the first ink connection flow path and the second ink connection flow path;

[0025] Figure 11B This is a cross-sectional view showing the first ink connection flow path and the second ink connection flow path;

[0026] Figure 12A This is a cross-sectional view showing the first ink connection flow path and the second ink connection flow path;

[0027] Figure 12B This is a cross-sectional view showing the first ink connection flow path and the second ink connection flow path;

[0028] Figure 13 It shows along Figure 7 A diagram of the cross-section XIII-XIII;

[0029] Figure 14 It is a cross-sectional view along the column of jet ports in the first ink connection flow path;

[0030] Figure 15A It is a cross-sectional view along the column of jet ports in the first ink connection flow path;

[0031] Figure 15B It is a cross-sectional view along the column of jet ports in the first ink connection flow path;

[0032] Figure 16A This is a diagram showing an example of a pressure regulating unit;

[0033] Figure 16B This is a diagram showing an example of a pressure regulating unit;

[0034] Figure 16C This is a diagram showing an example of a pressure regulating unit;

[0035] Figure 17A This is a 3D view of the circulating pump.

[0036] Figure 17B This is a 3D view of the circulating pump.

[0037] Figure 18 It is a cross-sectional view along line XVIII-XVIII of the circulating pump;

[0038] Figure 19A It is a diagram explaining the ink flow inside a liquid ejector head;

[0039] Figure 19B It is a diagram explaining the ink flow inside a liquid ejector head;

[0040] Figure 19C It is a diagram explaining the ink flow inside a liquid ejector head;

[0041] Figure 19D It is a diagram explaining the ink flow inside a liquid ejector head;

[0042] Figure 19E It is a diagram explaining the ink flow inside a liquid ejector head;

[0043] Figure 20A This is a schematic diagram showing the circulation path of ink of one color in the jetting unit;

[0044] Figure 20B This is a schematic diagram showing the circulation path of ink of one color in the jetting unit;

[0045] Figure 21 This is a diagram showing the opening plate;

[0046] Figure 22 This is a diagram showing the substrate of the spraying element;

[0047] Figure 23A It is a cross-sectional view showing the ink flow in different parts of the jetting unit;

[0048] Figure 23B It is a cross-sectional view showing the ink flow in different parts of the jetting unit;

[0049] Figure 23C It is a cross-sectional view showing the ink flow in different parts of the jetting unit;

[0050] Figure 24A This is a cross-sectional view showing the vicinity of the injection port in the injection module;

[0051] Figure 24B This is a cross-sectional view showing the vicinity of the injection port in the injection module;

[0052] Figure 25 This is a diagram showing the substrate of the jetting element as a comparative example;

[0053] Figure 26A This is a diagram showing the flow path configuration of a liquid jet head compatible with three colors of ink;

[0054] Figure 26B This is a diagram showing the flow path configuration of a liquid ejector head compatible with three colors of ink; and

[0055] Figure 27 This diagram shows the connection status of the ink cartridge, external pump, and liquid jet head. Detailed Implementation

[0056] Figure 1 This is a schematic perspective view of a liquid jetting apparatus 2000 to which the liquid jetting head 1000 of this embodiment can be applied. The liquid jetting apparatus 2000 of this embodiment is an inkjet printing apparatus employing a serial scanning scheme, which prints images on a printing medium P by jetting liquid (hereinafter also referred to as ink) from liquid jetting heads 1000 and 1001. Liquid jetting heads 1000 and 1001 can be mounted on a carriage 10, and the carriage 10 moves along a guide axis 11 in the main scanning direction (i.e., the X direction). The printing medium P is conveyed by a transfer roller (not shown schematically) in a secondary scanning direction (i.e., the Y direction) intersecting (in this embodiment, perpendicular to) the main scanning direction.

[0057] Two types of liquid ejector heads are mounted on the bracket 10, with liquid ejector head 1000 capable of ejecting three types of ink and liquid ejector head 1001 capable of ejecting six types of ink. Ink is supplied under pressure from nine types of ink cartridges 2 (21, 22, 23, 24, 25, 26, 27, 28, 29) to each liquid ejector head via ink supply lines 30. A supply pump for supplying under pressure, which will be described later, is mounted on the ink supply unit 12.

[0058] As a variation, the number of ink cartridge types can be reduced to seven by setting the three types of ink in the liquid ejector head 1000 to the same type of ink, or a liquid ejector device capable of ejecting 12 or more types of ink can be constructed by further adding the installed liquid ejector heads.

[0059] The liquid jet head 1000 is fixedly supported on the bracket 10 by the positioning unit and electrical contacts of the bracket 10, and performs printing by jetting ink while moving in the scanning direction (i.e., the X direction).

[0060] Figure 2 This is a perspective view of the liquid injection head 1000 in this embodiment, and Figure 3 This is an exploded perspective view of the liquid jet head 1000. The liquid jet head 1000 includes a printing element unit 100, a circulation unit 200, a head housing unit 300, and a cover 502. The printing element unit 100 includes a printing element substrate 110, a support member 102 having ink supply connection paths 310 and 320 to the printing element substrate 110, an electrical wiring strip 103, and an electrical contact substrate 104.

[0061] The electrical contact substrate 104 has electrical contacts that contact the bracket 10 and provides drive signals and energy to the circulation pump 203 mounted on the circulation unit 200 via the circulation unit connector 106 and pump wiring (not shown schematically). In addition, the electrical contact substrate 104 supplies drive signals and energy for ink ejection to the printing element unit 100 via the electrical wiring strip 103.

[0062] Electrical connections are performed via anisotropic conductive films (not shown schematically), wire bonding, or solder mounting, but the connection method is not limited to these. In this embodiment, the connection between the printed element substrate 100 and the electrical wiring tape 103 is performed via wire bonding, and the electrical connection portion is sealed with a sealing material and protected from ink corrosion and external impacts.

[0063] The circulation unit 200 includes a first pressure regulating mechanism 201 and a second pressure regulating mechanism 202 (see reference). Figure 4 (to be described later) and circulation pump 203. Through ink supply tube 30 (see reference) Figure 1 Ink is supplied from the ink cartridge 2 to the ink supply port 32 via the head housing unit 300 having a tube connection unit 31. In this embodiment, the circulation unit 200 is fixed to the head housing unit 300 with screws 501, thereby forming an ink supply path.

[0064] As a sealing member used at the connection point in the ink supply path, an elastic member, such as rubber or an elastomer, is employed. The printing element unit 100 is attached and secured to the head housing unit 300, forming the ink supply path. An elastomer may also be used at the connection point in the ink supply path. The head housing unit 300 is constructed by combining components obtained through injection molding of a filler-containing resin, for positioning with the carrier 10 and for forming the shape of the ink flow path.

[0065] On the printed element substrate 110, a column of ejection ports arranged along the Y direction is formed. A column of ejection ports is also provided in the X direction.

[0066] Figure 4This is a schematic diagram showing the circulation path of an ink of a certain color under constant conditions in the liquid jetting device 2000 applied in this embodiment. The ink is supplied from the ink cartridge 21 to the liquid jetting head 1000 by the supply pump P0 under pressure. After dust and the like are removed by the filter 204, the ink is supplied to the first pressure regulating mechanism 201.

[0067] exist Figure 4 In China (also) Figure 6 (As will be described later), "L" is described in the first pressure regulating mechanism 201 and "H" is described in the second pressure regulating mechanism 202. This indicates that "H" corresponds to a high negative pressure and "L" corresponds to a low negative pressure, which is the opposite of the case where H and L are interchanged based on a positive pressure. The pressure in the first pressure control chamber 211 is regulated to a predetermined pressure (negative pressure) by the first pressure regulating mechanism 201. The circulation pump 203 is a piezoelectric diaphragm pump that delivers liquid by inputting a drive voltage to a piezoelectric element attached to a diaphragm to change the internal volume of the pump chamber and alternately actuating two check valves due to pressure changes.

[0068] The circulation pump 203 delivers ink from the second pressure control chamber 221 on the low-pressure (high negative pressure) side to the first pressure control chamber 211 on the high-pressure (low negative pressure) side. The pressure in the second pressure control chamber 221 is adjusted by the second pressure regulating mechanism 202 to be lower than the pressure in the first pressure control chamber 211. A plurality of pressure chambers 113 with ejection ports capable of ejecting liquid are arranged on the printing element substrate 110, and a common supply flow path 111 and a common collection flow path 112 are connected to each pressure chamber 113.

[0069] The common supply flow path 111 is connected to the first ink connection flow path 310 and the first pressure control chamber 211 via the first bubble storage flow path (bubble reservoir section) 301, and therefore its pressure is regulated to the high-pressure (upstream) side. The common collection flow path 112 is connected to the second ink connection flow path 320 and the second pressure control chamber 221 via the second bubble storage flow path 302, and therefore its pressure is regulated to the low-pressure (downstream) side. The pressure difference between the common supply flow path 111 and the common collection flow path 112 generates pressure in each pressure chamber 113. Figure 4 The flow is in the direction of the middle arrow a. Ink that has become locally thickened near the ejection port, where no ink is ejected during standby or printing, is collected from the pressure chamber 113 by the ink flow generated due to this pressure difference, and thus ejection failures can be suppressed.

[0070] In this embodiment, each of the first bubble storage flow path 301 and the second bubble storage flow path 302 has an internal volume capable of temporarily storing bubbles within the ink path, which have been generated during printing and standby.

[0071] Figures 5A to 5C All views are cross-sectional views taken at different locations along the Y direction on the printing element substrate 110. The printing element substrate 110 includes a Si substrate 120 and an ejection port member 130. Circuitry (not shown schematically) and a heater 115, serving as a pressure generating mechanism, are arranged on the Si substrate. The ejection port member is obtained by photolithographically patterning a pressure chamber 113 corresponding to the heater 115 and an ejection port 114. In this embodiment, ejection energy is obtained by applying a voltage to the heater 115 and causing the ink in the pressure chamber 113 to foam; however, the pressure generating mechanism is not limited to this. Piezoelectric elements can also be used instead of the heater. The Si substrate 120 includes a bonding surface 123, which is adhered to and fixed to the support member 102 and connected to each ink supply path.

[0072] In this embodiment, to improve ink supply to the pressure chamber 113 and reduce costs by miniaturizing the substrate, the common supply flow path 111 and the common collection flow path 112 are constructed with a spacing of less than 1 mm in the X direction. Furthermore, considering printing efficiency on the printing medium P, four jet port rows are arranged, with the jet ports arranged at 600 dpi. The resolution of the jet port arrangement and the number of jet port rows are not limited to this.

[0073] Figure 5A A cross-section of the common supply flow path opening 121 is shown at the location where the common supply flow path 111 communicates with the connecting surface 123. Figure 5B A cross-section is shown at a location where neither the common supply path 111 nor the common collection path 112 communicates with the connecting surface 123. Figure 5C A cross-section of the common collection flow path opening 122 is shown at the location where the common collection flow path 112 communicates with the connecting surface 123.

[0074] To control the pressure difference between the common supply path 111 and the common collection path 112, it is necessary to separate the ink supply paths except for the pressure chamber 113 and the pressure regulating mechanism unit. Therefore, in Figure 5B At the location shown in the cross-section, the first ink connection flow path 310 and the second ink connection flow path 320 are separated in the direction of the jet port array. Both the common supply flow path 111 and the common collection flow path 112 have very small cross-sectional areas, and there is a concern about insufficient ink supply due to pressure loss caused by liquid transport. Therefore, it is desirable to shorten the cross-sectional area as much as possible. Figure 5BThe common supply flow path 111 and common collection flow path 112 are shown but not connected to the connecting surface 123. Therefore, it is desirable to have a large number of [various flow paths] in the direction of the jet port array. Figure 5A The public supply flow path opening 121 and a large number of [other features] are shown. Figure 5C The common collection flow path opening 122 is shown.

[0075] exist Figure 3 In the exploded perspective view, for each color, the first ink connection path 310 is arranged at nine sections, and the second ink connection path 320 is arranged at eight sections. The number of connection sections varies depending on the length and width of the jet port column when connecting the separated ink supply paths. In this embodiment, Figure 5B The cross-sectional area of ​​the common supply flow path 111 and the common collection flow path 112 is 0.1 mm. 2 Or smaller, and the distance between the public supply flow path opening 121 and the public collection flow path opening 122 is 7.5 mm or smaller.

[0076] Figure 6 This illustration shows the ink flow in the circulation path for one color when printing is performed using most of the ejection ports in this embodiment. When printing is performed using most of the ejection ports, the ink flow differs from the circulation under constant conditions, and ink is supplied to the pressure chamber 113 from both the common supply path 111 and the common collection path 112.

[0077] When ink is ejected from pressure chamber 113, ink is supplied from common supply path 111 and common collection path 112, respectively. Common supply path 111 supplies ink from first ink connection path 310 and from first pressure control chamber 211 via first bubble storage path 301 to pressure chamber 113. Furthermore, common collection path 112 supplies ink from second ink connection path 320 and from second pressure control chamber 221 to pressure chamber 113 via second bubble storage path 302. Circulation pump 203 pumps ink from second pressure control chamber 221 to first pressure control chamber 211 in the same manner as in a constant state.

[0078] At this time, the second pressure control chamber 221 supplies ink to the second ink connection flow path 320 and the circulation pump 203. Furthermore, the second pressure control chamber 221 maintains constant pressure by supplying ink from the first pressure control chamber 211 via a bypass flow path, which connects the first and second pressure control mechanisms 201 and 202, through a second pressure regulating mechanism 202. The first pressure control chamber 211 supplies ink to the second pressure regulating mechanism 202 and the first ink connection flow path 310, but maintains constant pressure by collecting ink from the ink cartridge 21, which serves as the ink supply source, through the first pressure control mechanism 20, including the ink delivered by the circulation pump 203.

[0079] As described above, depending on the printing state, the ink flow direction in the common collection flow path 112 changes, and consequently, the ink flow direction in the second ink connection flow path 320 and the second bubble storage flow path 302 changes.

[0080] Figure 7 This is a side view showing the liquid injection head 1000. Figure 8A It is along Figure 7 The sectional view of VIIIa-VIIIa in the middle, and Figure 8B It is along Figure 7 The image shows a cross-sectional view of VIIIb-VIIIb. A row of ejection ports is arranged on the printing element substrate 110 along the Y direction (the direction of movement of the printing medium P), and ink is ejected from each ejection port in the Z direction. The first ink connection flow path 310 and the second ink connection flow path 320 include a head housing unit 300 and a support member 102.

[0081] The printing element substrate 110 is supported by the support member 102 and is supported to connect from the first pressure control chamber 211 via the first bubble storage flow path 301 and the first ink connection flow path 310 to the common supply flow path opening 121 and the common supply flow path 111. Furthermore, the printing element substrate 110 is supported to connect from the second pressure control chamber 221 via the second bubble storage flow path 302 and the second ink connection flow path 320 to the common collection flow path opening 122 and the common collection flow path 112.

[0082] The pressure in the first pressure control chamber 211 and the second pressure control chamber 221 is controlled to be constant by a pressure regulating mechanism constructed within the circulation unit 200.

[0083] Figure 9This is a schematic diagram showing the interior of the circulation unit 200 in an understandable manner. In the circulation unit 200, ink is supplied under pressure from the ink supply unit 12 through the ink supply port 32 and via the filter 204 to the first pressure regulating mechanism 201. The first pressure regulating mechanism 201 includes a valve 232, a valve spring 233, a flexible member 231, a pressing plate 235, and a pressure regulating spring 234.

[0084] In the first pressure control chamber 211, when the volume of the first pressure control chamber 211 decreases due to ink discharge, the pressing plate 235 deforms the flexible member 231 and the pressure adjusting spring 234, attempting to maintain a constant pressure within the first pressure control chamber 211. By compressing and deforming the pressure adjusting spring 234, the valve 232 can be opened, and ink is supplied to the first pressure control chamber 211 by deforming the valve spring 233 in the compression direction via the valve 232. This operation allows the pressure within the first pressure control chamber 211 and the ink supply to be kept constant. The negative pressure in the first pressure control chamber 211 is set by the contact position between the pressure adjusting spring 234 and the pressing plate 235 of the valve 232.

[0085] The second pressure regulating mechanism 202 of the second pressure control chamber 221 includes a valve 242, a valve spring 243, a flexible member 241, a pressing plate 245, and a pressure regulating spring 244. Except that the ink supply source is changed from the ink supply unit 12 to the first pressure control chamber 211, the pressure regulating principle in the second pressure regulating mechanism 202 is the same as that in the first pressure regulating mechanism 201.

[0086] A circulation pump 203 is connected to deliver ink from the second pressure control chamber 221 to the first pressure control chamber 211. In this embodiment, a compact diaphragm pump including a piezoelectric element is used as the circulation pump 203. The pump can be driven by applying a voltage pulse to the piezoelectric element, and therefore, the circulation pump 203 can be controlled to turn on / off by inputting a voltage pulse. The circulation pump 203 moves ink from the second pressure control chamber 221 to the first pressure control chamber 211, increasing the pressure in the first pressure control chamber 211 by an amount corresponding to the delivered ink, and decreasing the pressure in the second pressure control chamber 221 by an amount corresponding to the delivered ink.

[0087] The second pressure control chamber 221 collects ink corresponding to the amount of pressure reduction via the second pressure regulating mechanism 202. However, the second pressure regulating mechanism 202 collects ink from the first pressure control chamber 211 and the pressure chamber 113, thus creating a circulating flow while maintaining a constant pressure. This circulating flow via the pressure chamber 113, as described above, removes ink that has thickened due to evaporation near the ejection port, thereby enabling stable ejection.

[0088] Figure 10A This is a cross-sectional view showing the first ink connection flow path 310 connected to the first pressure control chamber 211 in this embodiment, and Figure 10B This is a cross-sectional view showing the second ink connection flow path 320 connected to the second pressure control chamber 221. Additionally, Figure 10C This is a perspective view showing the flow path in the connection portion between the head housing unit 300 and the support member 102 in an understandable manner. The printing element substrate 110 includes an ejection port member 130 and a Si substrate 120. A heat-preserving heater (not shown schematically) for stabilizing ejection is arranged on the Si substrate 120. Furthermore, to ensure temperature uniformity across the entire printing element substrate 110 and for bonding stability with the Si substrate 120, the support member 102 is made of alumina material, which exhibits linear expansion similar to that of Si and has high thermal conductivity.

[0089] exist Figure 10A and Figure 10B In the diagram, the arrows (solid lines) shown within the flow path indicate the flow of circulating ink driven by the circulation pump 203 when printing is not performed. Specifically, in Figure 10A In the process, ink flows from the first pressure control chamber 211 through the head housing unit 300, which forms the first bubble storage flow path 301, and the support member 102, which forms part of the first ink connection flow path 310, to the common supply flow path opening 121. The ink then flows from the common supply flow path 111 through the pressure chamber 113 from which it ejects ink to the common collection flow path 112, and is collected in the common collection flow path opening 122. The head housing unit 300, which forms the second bubble storage flow path 302, and the second ink connection flow path 320, including the support member 102, supply the ink collected in the common collection flow path opening 122 to the second pressure control chamber 221. The ink is then transported from the second pressure control chamber 221 to the first pressure control chamber 211 by the circulation pump 203, completing one cycle of the circulating flow.

[0090] The ink flow is circulated within the ink flow path of the liquid ejector head 1000, and therefore, air bubbles 500 appear somewhere in the flow path of the liquid ejector head 1000. Air bubbles 500 appear during ink filling, or are caused by foaming due to ink flow, or by supersaturation of dissolved gases in the ink due to temperature rise and pressure drop within the liquid ejector head 1000. If air bubbles 500 flow into the pressure chamber 113, there is a possibility of ink ejection failure, leading to image defects. Therefore, to prevent air bubbles 500 from flowing into the pressure chamber 113, it is desirable to store the air bubbles 500 in the circulation flow path away from the pressure chamber 113.

[0091] In the case of a conventional liquid jet head that lacks a flow path for storing air bubbles, it is necessary to operate the liquid jet head within a range that prevents the dissolved gas from becoming supersaturated by controlling the degree of ink degassing, or to expel the generated air bubbles to the outside of the liquid jet head each time an air bubble appears. Methods for controlling the degree of degassing include pressure-reducing stirring and degassing modules using hollow fiber membranes; however, these methods increase costs and the size and weight of the liquid jet head, potentially affecting printing speed. Furthermore, if ink containing air bubbles is expelled each time an air bubble appears, the ink intended for printing is used as waste ink, raising concerns about impacting printing costs.

[0092] Therefore, in this embodiment, by tilting the top plates of the first bubble storage flow path 301 and the second bubble storage flow path 302, the bubbles 500 that have already appeared in the bubble storage flow path are guided by buoyancy to a position away from the pressure chamber 113 within the circulation flow path, and simultaneously the bubbles 500 are temporarily stored at this distant position. Here, the top plate refers to the inner wall of the flow path as a surface forming part of the flow path, and the component of the normal vector of the inner wall of the flow path relative to the surface of the top plate has a component in the direction of gravity. Most bubbles generated due to environmental changes (e.g., increased temperature) are tiny bubbles with a diameter of 1 mm or less, and therefore, buoyancy must be increased to counteract the resistance generated in the bubbles 500 due to ink flow.

[0093] In this embodiment, to prevent the ink near the ejection port from thickening, a circulating flow occurs even when printing is not performed. Therefore, ink flows toward the print element substrate 110 in the first ink connection flow path 310 and the first bubble storage flow path 301, making it difficult to guide the bubble 500 away from the pressure chamber 113. The resistance caused by the ink flow is proportional to the square of the ink flow velocity, and therefore, reducing the ink flow velocity is effective in reducing resistance. By reducing the ink flow velocity to reduce resistance, it becomes easier to guide the bubble 500 away from the pressure chamber 113 by buoyancy.

[0094] Furthermore, in this embodiment, the minimum vertical cross-sectional area of ​​the first bubble storage flow path 301 in the ink circulation direction is more than 20 times the minimum vertical cross-sectional area of ​​the first ink connection flow path 310 in the ink circulation direction. For example... Figure 10C As shown, the head housing unit 300 constituting the first bubble storage flow path 301 extends in the Y direction, and therefore, the first bubble storage flow path 301 also extends in the Y direction. This configuration is designed such that, in a flow path structure such as this, the minimum cross-sectional area of ​​the first bubble storage flow path 301 is 20 times or more the minimum cross-sectional area of ​​the first ink connection flow path 310. Even when the minimum cross-sectional area of ​​the first bubble storage flow path 301 is two or more times the minimum cross-sectional area of ​​the first ink connection flow path 310, the effects described in this embodiment can be obtained. Furthermore, the first ink connection flow path 310 is provided at nine locations along the Y direction at the connection portions between the head housing unit 300 and the support member 102. Therefore, the ink flow rate can be reduced to 9 / 20 = 0.45. In this embodiment, the top plate surfaces of the first bubble storage flow path 301 and the first ink connection flow path 310 each have an angle (θ11, θ13) of approximately 40 to 50 degrees relative to the surface on which the injection ports are arranged.

[0095] As described above, by configuring the cross-sectional area of ​​the flow path such that the maximum flow velocity in the first bubble storage flow path 301 is less than the maximum flow velocity in the first ink connection flow path 310, the resistance caused by the ink flow to the bubble 500 is reduced. This allows the bubble 500, which has left the first ink connection flow path 310, to be guided to the top of the top plate of the first bubble storage flow path 301. Due to this configuration, for example, by reducing the flow velocity of the ink circulation flow in the first bubble storage flow path 301 to a sufficiently lower level than the flow velocity of the ink circulation flow in the first ink connection flow path 310, or by temporarily stopping the flow, the bubble 500 can be guided to a position away from the pressure chamber 113. This angle θ is determined by the coefficient of friction and the buoyancy-based moving force, the coefficient of friction being determined by the physical properties of the ink and the inner wall of the first ink connection flow path 310.

[0096] Regarding the components of the ink and the first ink connection flow path 310 used in the liquid jet head 1000 of this embodiment, it has been found that the effects of this embodiment are obtained by using a top plate surface with an angle of approximately 15 degrees or greater relative to the surface on which the jet ports are arranged. More preferably, it is desirable to set the top plate surface at an angle close to 90 degrees, at which 100% of the buoyancy component of the bubble 500 can be used as a moving force.

[0097] Furthermore, in this embodiment, the minimum cross-sectional area of ​​the first ink connection flow path 310 is ensured to be two or more times the total cross-sectional area (total area) of the connected common supply flow path opening 121. Consequently, the ink flow rate in the portion of the first ink connection flow path 310 with the minimum cross-sectional area becomes less than the ink flow rate near the common supply flow path opening 121, and therefore, the air bubble 500 becomes less likely to be drawn into the common supply flow path 111.

[0098] When the constant ink circulation flow has a certain speed setting, there is a possibility that air bubbles 500 may remain in the first ink connection flow path 310 depending on their volume. Similarly, in this case, as long as the air bubbles 500 can be expelled to the first air bubble storage flow path 301 side by setting a short ink circulation stop time, the air bubbles 500 can be guided to the top plate side of the first air bubble storage flow path 301 even if ink circulation resumes. It is not possible to set the circulation stop time during printing, and therefore, it is desirable to complete the expulsion of air bubbles 500 in a short time to prevent a decrease in productivity.

[0099] In this embodiment, similarly, in the inner wall of the second bubble storage flow path 302 and the second ink connection flow path 320 (refer to...) Figure 10B Each of the top plate surfaces has an angle (θ22, θ24) of approximately 40 to 50 degrees relative to the surface on which the injection ports are arranged. Thus, in addition to the moving force generated by buoyancy, the movement of bubble 500 to the second bubble storage flow path 302 can be completed in a short time by the dynamic pressure of the circulating flow.

[0100] Figure 11A and Figure 11B Each one is shown in the use of Figure 6 The diagram shows the behavior of ink flow and bubbles 500 when most of the jet ports are used to perform printing. Figure 11A This is a cross-sectional view showing the first ink connection flow path 310 connected to the first pressure control chamber 211, and Figure 11B This is a cross-sectional view showing the second ink connection flow path 320 connected to the second pressure control chamber 221. Figure 11A and Figure 11B The position of the cross section and Figure 10A and Figure 10B The cross-sections are located in the same position. When printing is performed using most of the injection ports, compared to... Figure 10A and Figure 10BIn the non-printing state shown, a larger amount of ink is supplied to the pressure chamber 113 in the circulating flow, and a large flow occurs in each flow path. Furthermore, in the first ink connection flow path 310 and the second ink connection flow path 320, the ink circulating flow is directed towards the pressure chamber 113. By increasing the ink flow rate, the ink flow velocity generally increases in the direction towards the pressure chamber 113.

[0101] Specifically, in the first ink connection flow path 310 and the second ink connection flow path 320, which are formed by the support member 102 with a relatively small flow path cross-sectional area, a high-velocity flow occurs, and the dynamic pressure applied to the bubble 500 increases. Therefore, the possibility of the bubble 500 flowing into the pressure chamber 113 increases. Furthermore, in this embodiment, the jetting energy in the pressure chamber 113 is generated by the heat energy of the heater 115, and therefore, the temperature of the printing element substrate 110 rises with jetting. As a result, the temperature in the circulating flow path formed within the support member 102 and the printing element substrate 110 becomes relatively high, and therefore, the dissolved gas in the ink becomes supersaturated, and the possibility of the bubble 500 appearing increases.

[0102] When printing is performed using most of the jet ports as described above, it is necessary to move the bubble 500 to the first bubble storage path 301 or the second bubble storage path 302 by periodically inducing a cycle or stopping the cycle during non-printing periods, depending on the amount of ink jetted and the jetting time. The time required to move the bubble 500 may be accompanied by printing termination as described above, and may reduce printing productivity. Therefore, in order to shorten the time required to move the bubble 500, it is also desirable to set the top plate surface at an angle close to 90 degrees, at which 100% of the buoyancy component of the bubble 500 can be used as the moving force.

[0103] As a modification example, there are cases where an ink temperature regulating heater is mounted on the printing element substrate 110, and cases where a resin material with low thermal conductivity is used for the support member 102 to emphasize the temperature regulation speed. In this case, the portion where heat-induced bubbles appear is confined to the vicinity of the Si substrate 120.

[0104] Furthermore, a common supply flow path 111 is formed within the printing element substrate 110 using Si substrate processing technology. Therefore, it is difficult to set a sufficient angle relative to the surface on which the jet ports are arranged, and the cross-sectional area of ​​the flow path is very small. Consequently, it is difficult to resist the circulating flow guiding the bubbles 500 to the first bubble storage flow path 301 by buoyancy. Therefore, depending on the amount of jet ink and printing time, it is necessary to periodically remove the bubbles 500 that have appeared in the common supply flow path 111 from the pressure chamber 113 by suction or the like. However, the amount of ink in the common supply flow path 111 is very small, and therefore, waste ink can be minimized.

[0105] Figure 12A This is a cross-sectional view showing the first bubble storage flow path 301 when a large number of bubbles 500 are stored, and Figure 12B This is a cross-sectional view showing the second bubble storage flow path 302 when a large number of bubbles 500 are stored. Figure 12A and Figure 12B The position of the cross section and Figure 10A and Figure 10B The positions of the cross sections are the same. When the bubbles 500 merge into the size of the almost closed flow path cross-sectional area, the resistance caused by the ink flow increases, causing the bubbles 500 to flow into the pressure chamber 113.

[0106] However, the cross-sectional area of ​​the top plate portion, including the first bubble storage flow path 301 and the second bubble storage flow path 302, is larger than the minimum cross-sectional area within each bubble storage flow path, and multiple slit portions (not shown schematically) are provided on the flow path wall along the direction of ink flow. The slit portions are constructed to be sufficiently narrow so that they are not blocked by the bubbles 500. Therefore, the relative ink flow rate within each bubble storage flow path is low, allowing ink to flow from the slits without moving the bubbles 500. This suppresses the inflow of bubbles 500 into the pressure chamber 113. In this embodiment, the slit portions have the shape of grooves with a width of 0.5 mm and a structure in which the stored and bound bubbles 500 are almost impossible to block the slit portions.

[0107] Even with the slit portion configured as described above, if a predetermined amount of bubbles 500 accumulate in the first bubble storage flow path 301 and the second bubble storage flow path 302, and reach a flow path with a small cross-sectional area and a high flow rate, there is a concern that the bubbles 500 may flow into the pressure chamber 113 under the dynamic pressure of the ink, potentially causing ejection malfunction. Therefore, in the case of a predetermined amount of bubbles 500 accumulating, a recovery operation needs to be performed by suction from the ejection port or the like to expel the bubbles 500 to the outside. Suction recovery devices that perform recovery operations by suction are widely used in inkjet printers for printing stability, and are not new designs for removing bubbles 500 that have already accumulated in the first bubble storage flow path 301 and the second bubble storage flow path 302.

[0108] Figure 13 It shows along Figure 7 A cross-sectional view of section XIII-XIII. Bubbles that have already been generated can be moved to the top plate portion via a first bubble storage flow path 301 and a second bubble storage flow path 302 having the widest possible flow path cross-sectional area. Therefore, it is desirable to form the first bubble storage flow path 301 and the second bubble storage flow path 302 with increased flow path cross-sectional areas until they are near the printed element substrate 110 where bubbles 500 may appear.

[0109] In this embodiment, when the common supply flow path opening 121 is alternately arranged at nine portions in the direction of the jet port array and the common collection flow path opening 122 is arranged at eight portions, each opening is connected by a flow path having a length of its long side in the Y direction that is greater than or equal to the length of each of the two ends of the jet port array. In this case, it is necessary to arrange branch portions to supply ink to each opening arranged with narrow spacing, but in this embodiment, as... Figure 8A and Figure 8B As shown in the cross-sectional view, the portion connected to the printing element substrate 110 is configured to have a branch portion having a triangular shape with a hypotenuse that is inclined in the X direction, which is the scanning direction. The hypotenuses of the triangular shape of the first ink connection flow path 310 connected to the common supply flow path opening 121 and the hypotenuses of the triangular shape of the second ink connection flow path 320 connected to the common collection flow path opening 122 are arranged in opposite directions.

[0110] As described above, a flow path is provided between the circulation unit and the supply flow path communicating with the pressure chamber. This flow path has a vertical cross-sectional area in the liquid circulation direction, which is two or more times the vertical cross-sectional area in the supply flow path in the liquid circulation direction. Furthermore, the flow path is inclined relative to the direction of gravity, and the component of the normal vector of the flow path has a component in the direction of gravity. Therefore, a liquid injection head and a liquid injection device can be provided that suppress the occurrence of injection failures without increasing the size of the device.

[0111] (Variation example)

[0112] A variation of the above-described implementation method will be described.

[0113] Figure 14 It is a cross-sectional view of the jet port column direction (Y direction) of the first ink connection flow path 310, and Figure 15A and Figure 15B Each is a cross-sectional view of the jet port column direction (Y direction) of the first ink connection flow path 310 when the delivery angle of the printing media changes. The shape of the liquid jet head 1000 is ideal because the width of the printing device is reduced by decreasing the width in the scanning direction (X direction). Furthermore, when multiple liquid jet heads 1000 are installed, the width of the carriage 10 movement is reduced, and therefore, it is desirable to reduce the width in the scanning direction (Y direction) because productivity will be improved.

[0114] In the case of a liquid ejector head that ejects two colors of ink, the circulation unit 200 (refer to...) Figure 3 The ink is installed at a position offset along the Y direction, which allows for a reduction in width. In this variation, as described above, the inner wall angles θ (θ31 to θ37) of the first ink connection flow path 310, the first bubble storage flow path 301, the second ink connection flow path 320, and the second bubble storage flow path 302 are configured to be at an angle of 45 degrees or greater relative to a plane perpendicular to the direction vector of gravity.

[0115] The liquid jet head 1000 performs printing while moving along the scanning direction (X direction) for the printing medium P, and therefore, there exists such as Figure 15A and Figure 15B The orientation of the printing medium P changes depending on the transport angles α and β of the printing medium P. A high degree of freedom in the transport angle of the printing medium P is desirable because it increases the range of applications for various purposes.

[0116] It is necessary to make the distance between the printing medium P and the plane on which the ejection ports 114 are arranged as uniform as possible; that is, the ejection ports 114 need to be arranged parallel to the printing medium P in order to maintain high landing accuracy of the ejected ink on the printing medium P. In this case, in order for the present invention to be effective, for the inner wall angles θ (θ42, θ44 to θ46) (θ51, θ53 to θ55, θ57), an angle of 15 degrees or greater relative to the plane perpendicular to the direction vector of gravity is ensured by taking into account the attachment angle of the liquid ejection head 1000. Figure 14 The liquid injection head 1000 shown is configured such that even considering Figure 15A and Figure 15B The angles α and β shown can also achieve the effects of this invention.

[0117] The construction of this embodiment is organized by defining the normal vector N30 of the plane on which the injection port 114 is arranged as a reference. Figure 14 In the aspects shown, similar to the liquid injection head 1000, the arrangement plane of the injection port 114 is the same as the vertical plane in the direction of gravity (Z direction), and therefore, the normal vector N30 is the same as the direction of gravity (Z direction). For the angle θ35 of the inner wall surface of the flow path to exert the effect of the present invention, the angle formed by the normal vector N35 and the gravity direction vector (Z direction) is 15 degrees or greater. This is equivalent to the condition that the angle formed by the normal vector N35 of the inner wall surface and the normal vector N30 of the arrangement plane of the injection port 114 is 15 degrees or greater.

[0118] By making the normal vector of the arrangement plane of the ejection port 114 of the liquid ejection head 1000 equal to the gravity direction vector (Z direction), the ink ejection direction and the gravity direction are the same. Therefore, during ink droplet flight and after ink droplet landing on the printing medium P, the ink droplet is not affected by gravity in the plane direction of the printing medium P, and thus, high printing accuracy can be obtained.

[0119] On the other hand, Figure 15A and Figure 15B In the modified example shown, the ejection port 114 of the liquid ejection head 1000 is arranged on a surface parallel to the transport surface of the printing medium P. At this time, by... Figure 15A The angle formed by the normal vectors N44 and N45 of the inner wall of the flow path and the normal vector N40 of the plane of the injection port 114 is... Figure 14 θ34 and θ35 shown are the same. By considering the angle formed by the normal vector N40 of the arrangement plane of the injection port 114 and the vector in the direction of gravity (Z direction), it can be verified whether the inner wall of each flow path can exhibit the effects of the present invention.

[0120] exist Figure 15A In the variant example shown, the angle formed by the normal vector N40 of the arrangement plane of the injection port 114 and the vector in the gravitational direction (Z direction) is angle α, and this is the same as the angle between the arrangement plane of the injection port 114 and the imaginary surface in the gravitational direction. The effects of the present invention can be obtained by using angle θ45, because by… Figure 14 The angle obtained by adding θ35 (defined in the original text) and angle α is 15 degrees or greater. Similarly, the effects of the present invention can be obtained by using angle θ44, because by... Figure 14 The angle obtained by subtracting the specified θ34 from the angle α is 15 degrees or greater.

[0121] Taking into account the effect of angle α, it is possible to verify whether the necessary angle or a larger angle is ensured by performing subtraction on the angle formed by the normal vector N40 of the arrangement plane of the injection port 114 as a reference and the vector in the direction of gravity (Z direction) and the angle formed by the normal vector N40 and the normal vector (N44, N45) of the inner wall of the flow path, provided that they include the same angular components, and by performing addition on the angle that does not include the same angular components.

[0122] exist Figure 15B In the example shown, by means of the above Figure 14 Similarly, by confirming the angle β, it is possible to verify whether the effects of the present invention can be obtained.

[0123] <Reference Example>

[0124] A more detailed reference example of the liquid jetting equipment described above will be provided.

[0125] <Pressure Regulation Unit>

[0126] Figures 16A to 16C Each figure is an example illustrating a pressure regulating unit. (See reference...) Figures 16A to 16C The structure and operation of the pressure regulating units (first pressure regulating unit 1120 and second pressure regulating unit 1150) incorporated in the liquid injection head 1000 will be explained in more detail below. The first pressure regulating unit 1120 and the second pressure regulating unit 1150 have substantially the same structure. Therefore, the first pressure regulating unit 1120 will be used as an example in the following description, and for the second pressure regulating unit 1150, in... Figures 16A to 16C The symbols described herein only correspond to the parts of the first pressure regulating unit 1120. In the case of the second pressure regulating unit 1150, when interpreted, the first valve chamber 1121 described below changes to the second valve chamber 1151, and when interpreted, the first pressure control chamber 1122 changes to the second pressure control chamber 1152.

[0127] The first pressure regulating unit 1120 has a first valve chamber 1121 and a first pressure control chamber 1122 formed within a cylindrical housing 1125. The first valve chamber 1121 and the first pressure control chamber 1122 are separated from each other by a partition 1123 disposed within the cylindrical housing 1125. However, the first valve chamber 1121 communicates with the first pressure control chamber 1122 via a communication port 1191 formed in the partition 1123. A valve 1190 is disposed in the first valve chamber 1121, which switches the connection and disconnection between the first valve chamber 1121 and the first pressure control chamber 1122 via the communication port 1191. The valve 1190 is held in a position facing the communication port 1191 by a valve spring 1200 and has a configuration that allows the valve 1190 to be in close contact with the partition 1123 by the bias force of the valve spring 1200. The ink flow through the communication port 1191 is cut off by the valve 1190 making close contact with the separator 1123. To enhance the close contact with the separator 1123, the contact portion between the valve 1190 and the separator 1123 is preferably formed by an elastic member. Furthermore, at the center portion of the valve 1190, a valve shaft 1190a, inserted into the communication port 1191, is positioned to protrude therefrom. By pressing the valve shaft 1190a against the biasing force of the valve spring 1200, the valve 1190 separates from the separator 1123, allowing ink flow through the communication port 1191. Hereinafter, the state in which the ink flow through the communication port 1191 is cut off by the valve 1190 is referred to as the "closed state," and the state in which the ink flow through the communication port 1191 is permitted is referred to as the "open state."

[0128] The opening of the cylindrical housing 1125 is closed by the flexible member 1230 and the pressing plate 1210. A first pressure control chamber 1122 is formed by the flexible member 1230, the pressing plate 1210, the peripheral wall of the housing 1125, and the partition 1123. The pressing plate 1210 is configured to move with the flexible member 1230. The materials of the pressing plate 1210 and the flexible member 1230 are not particularly limited; however, for example, the pressing plate 1210 can be constructed by resin molding, and the flexible member 1230 by resin film. In this case, the pressing plate 1210 can be fixed to the flexible member 1230 by thermal welding.

[0129] A pressure regulating spring 1220 (biasing member) is provided between the pressing plate 1210 and the separator 1123. Through the biasing force of the pressure regulating spring 1220, the pressing plate 1210 and the flexible member 1230 are biased in the direction of increasing internal volume of the first pressure control chamber 1122, such as... Figure 16AAs shown. Furthermore, when the pressure within the first pressure control chamber 1122 decreases, the pressing plate 1210 and the flexible member 1230 move against the pressure of the pressure adjusting spring 1220 in the direction of decreasing internal volume of the first pressure control chamber 1122. Then, when the internal volume of the first pressure control chamber 1122 decreases to a predetermined volume, the pressing plate 1210 contacts the valve shaft 1190a of the valve 1190. Afterwards, when the internal volume of the first pressure control chamber 1122 further decreases, the valve 1190, together with the valve shaft 1190a, moves against the biasing force of the valve spring 1200 and separates from the separator 1123. Thus, the communication port 1191 enters the open state ( Figure 16B (The state in the middle).

[0130] In this embodiment, the connection settings within the loop path are configured such that when the connection port 1191 is in the open state, the pressure in the first valve chamber 1121 is higher than the pressure in the first pressure control chamber 1122. Consequently, when the connection port 1191 is in the open state, ink flows from the first valve chamber 1121 into the first pressure control chamber 1122. Through this ink inflow, the flexible member 1230 and the pressing plate 1210 are displaced in a direction that increases the internal volume of the first pressure control chamber 1122. As a result, the pressing plate 1210 separates from the valve shaft 1190a of the valve 1190, and the valve 1190 comes into close contact with the separator 1123 by the biasing force of the valve spring 1200, and the connection port 1191 enters the closed state. Figure 16C (The state in the middle).

[0131] As described above, in the first pressure regulating unit 1120 of this embodiment, when the pressure in the first pressure control chamber 1122 drops to a predetermined pressure or lower (for example, when the negative pressure increases), ink flows from the first valve chamber 1121 into the first pressure control chamber via the communication port 1191. Therefore, this configuration is designed so that the pressure in the first pressure control chamber 1122 no longer decreases. Thus, the first pressure control chamber 1122 is controlled to maintain the pressure within a predetermined range.

[0132] Next, the pressure within the first pressure control chamber 1122 will be explained in more detail.

[0133] Consider the following state ( Figure 16B In the state described above, the flexible member 1230 and the pressing plate 1210 are displaced according to the pressure in the first pressure control chamber 1122, and the pressing plate 1210 contacts the valve shaft 1190a, and the communication port 1191 enters the open state as described above. At this time, the relationship of the forces applied to the pressing plate 1210 is represented by the following equation 1.

[0134] Equation 1: P2×S2 + F2 +(P1-P2)×S1 + F1 = 0

[0135] Furthermore, when solving Equation 1 with respect to P2, we obtain:

[0136] P2 = -(F1 + F2 + P1×S1) / (S2-S1) Equation 2

[0137] P1: Pressure (gauge pressure) in the first valve chamber 1121

[0138] P2: Pressure (gauge pressure) within the first pressure control chamber 1122

[0139] F1: Spring force of valve spring 1200

[0140] F2: Spring force of pressure regulating spring 1220

[0141] S1: Pressure receiving area of ​​valve 1190

[0142] S2: Pressure receiving area of ​​pressure plate 1210

[0143] Here, regarding the directions of the spring force F1 of the valve spring 1200 and the spring force F2 of the pressure regulating spring 1220, the direction in which the valve 1190 and the press plate 1210 are pressed is taken as the positive direction (in...). Figure 16B (In the middle, to the left). In addition, regarding the pressure P1 in the first valve chamber 1121 and the pressure P2 in the first pressure control chamber 1122, the structure is designed such that P1 satisfies the relationship P1≥P2.

[0144] With the communication port 1191 in the open state, the pressure P2 in the first pressure control chamber 1122 is determined by Equation 2, and the structure is designed such that the relationship P1 ≥ P2 holds. Therefore, with the communication port 1191 in the open state, ink flows from the first valve chamber 1121 into the first pressure control chamber 1122. As a result, the pressure P2 in the first pressure control chamber 1122 no longer decreases, and P2 remains within a predetermined range.

[0145] On the other hand, when the pressing plate 1210 enters the valve shaft 1190a and the connecting port 1191 enters the valve shaft 1190a, the pressing plate 1210 no longer contacts the valve shaft 1190a. Figure 16C The relationship of the forces applied to the pressure plate 1210 in the closed state is represented by Equation 3.

[0146] P3×S3 + F3 = 0 Equation 3

[0147] Here, solving equation 3 with respect to P3 yields the following:

[0148] P3 = -F3 / S3 Equation 4

[0149] F3: The spring force of the pressure regulating spring 1220 when the pressure plate 1210 and the valve shaft 1190a are not in contact.

[0150] P3: Pressure (gauge pressure) in the first pressure control chamber 1122 when the press plate 1210 and valve shaft 1190a are not in contact.

[0151] S3: Pressure receiving area when the pressure plate 1210 and valve shaft 1190a are not in contact.

[0152] here, Figure 16C The pressing plate 1210 and the flexible member 1230 are shown to have been installed. Figure 16C The components are shifted to the rightward direction to their maximum displacement limit. This is achieved by the pressure plate 1210 and the flexible member 1230. Figure 16C The displacement during the state changes the pressure P3 in the first pressure control chamber 1122, the spring force F3 of the pressure adjusting spring 1220, and the pressure receiving area S3 of the pressing plate 1210. Specifically, when the pressing plate 1210 and the flexible member 1230 are located in the state... Figure 16C Distance from center to left Figure 16C When the pressure plate 1210 and the flexible member 1230 are positioned further apart, the pressure receiving area S3 of the pressure plate 1210 decreases, and the spring force F3 of the pressure regulating spring 1220 increases. As a result, according to the relationship shown in Equation 4, the pressure P3 within the first pressure control chamber 1122 decreases. Therefore, according to Equations 2 and 4, when the pressure P3 from... Figure 16B The state transition in Figure 16C During this state, the pressure within the first pressure control chamber 1122 gradually increases (i.e., the negative pressure decreases and becomes closer to the positive pressure side). Specifically, as the pressure within the first pressure control chamber 1122 gradually increases, the pressing plate 1210 and the flexible member 1230 gradually shift to the right from the closed state of the communication port 1191, eventually reaching the limit of the increase in the internal volume of the first pressure control chamber 1122. In other words, the negative pressure decreases.

[0153] <Circulation Pump>

[0154] Next, refer to Figure 17A , Figure 17B and Figure 18 The structure and operation of the circulation pump 1500 incorporated in the liquid injection head 1000 described above are explained in detail.

[0155] Figure 17A and Figure 17BEach image is a 3D view of the 1500 circulating pump. Figure 17A This is a perspective view showing the front of the circulation pump 1500, and Figure 17B This is a perspective view showing the rear side of the circulation pump 1500. The housing of the circulation pump 1500 includes a pump housing 1505 and a cover 1507 fixed to the pump housing 1505. The pump housing 1505 includes a housing body 1505a and a flow path connecting member 1505b bonded and fixed to the outer surface of the housing body 1505a. Each of the housing body 1505a and the flow path connecting member 1505b has a pair of through holes communicating with each other at two different locations. The pair of through holes at one location forms a pump supply hole 1501, and the pair of through holes at the other location forms a pump discharge hole 1502. The pump supply hole 1501 is connected to a pump inlet flow path 1170 connected to a second pressure control chamber 1152, and the pump discharge hole 1502 is connected to a pump outlet flow path 1180 connected to a first pressure control chamber 1122. Ink supplied from the pump supply hole 1501 passes through the pump chamber 1503 (see below). Figure 18 ), and discharged from pump discharge port 1502.

[0156] Figure 18 yes Figure 17A The diagram shows a cross-sectional view of the circulating pump 1500 along line XVII-XVII. A diaphragm 1506 is connected to the inner surface of the pump housing 1505, and a pump chamber 1503 is formed between the diaphragm 1506 and a recessed portion formed in the inner surface of the pump housing 1505. The pump chamber 1503 communicates with a pump supply port 1501 and a pump discharge port 1502 formed in the pump housing 1505. Furthermore, a check valve 1504a is provided at the middle portion of the pump supply port 1501, and a check valve 1504b is provided at the middle portion of the pump discharge port 1502. Specifically, the check valve 1504a is formed in a space 1512a at the middle portion of the pump supply port 1501, allowing it to... Figure 18 The arrangement is shifted from center to left. Additionally, a check valve 1504b is formed within a space 1512b in the middle portion of the pump discharge port 1502 to enable... Figure 18 Arranged by moving from the center to the right.

[0157] When the internal volume of the pump chamber 1503 increases due to the displacement of the diaphragm 1506, thereby reducing the pressure in the pump chamber 1503, the check valve 1504a separates from the opening of the pump supply port 1501 within the space 1512a (i.e., in Figure 18(Moving to the left). The check valve 1504a separates from the opening of the pump supply port 1501 within space 1512a, creating an open state in which ink can flow through the pump supply port 1501. Furthermore, when the internal volume of the pump chamber 1503 decreases due to the displacement of the diaphragm 1506, thereby pressurizing the pump chamber 1503, the check valve 1504a comes into close contact with the wall surface on the periphery of the opening of the pump supply port 1501. As a result, a closed state is created, in which the ink flow through the pump supply port 1501 is cut off.

[0158] On the other hand, when the pump chamber 1503 is depressurized, the check valve 1504b comes into close contact with the wall surface around the opening of the pump housing 1505 and is closed, in which the ink flow through the pump discharge port 1502 is cut off. Furthermore, when the pump chamber 1503 is pressurized, the check valve 1504b separates from the opening of the pump housing 1505 and moves to the side of space 1512b (i.e., in...). Figure 18 (Move to the right from the center), and allow the ink to flow through the pump discharge port 1502.

[0159] The material of each of the check valves 1504a and 1504b can be any material that can be deformed according to the pressure inside the pump chamber 1503, and the check valves 1504a and 150b can be formed by a membrane or sheet of, for example, an elastic member (such as EPDM and elastomers), or polypropylene.

[0160] As previously described, the pump chamber 1503 is formed by connecting the pump housing 1505 and the diaphragm 1506 together. Therefore, when the diaphragm 1506 deforms, the pressure within the pump chamber 1503 changes. For example, when the diaphragm 1506 shifts towards the pump housing 1505 (in... Figure 18 When the pump chamber 1503 is shifted to the right and its internal volume decreases, the pressure inside the pump chamber 1503 increases. As a result, the check valve 1504b, positioned facing the pump discharge port 1502, opens, and ink is discharged from the pump chamber 1503. Meanwhile, the check valve 1504a, positioned facing the pump supply port 1501, comes into close contact with the wall surface around the pump supply port 1501, thus preventing ink from flowing back from the pump chamber 1503 to the pump supply port 1501.

[0161] Conversely, when the diaphragm 1506 shifts in the direction of expansion of the pump chamber 1503, the pressure within the pump chamber 1503 decreases. Consequently, the check valve 1504a, positioned facing the pump supply port 1501, opens, and ink is supplied to the pump chamber 1503. At this time, the check valve 1504b, positioned in the pump discharge port 1502, comes into close contact with the wall surface surrounding the opening formed in the pump housing 1505, and closes the opening. Therefore, backflow of ink from the pump discharge port 1502 into the pump chamber 1503 is prevented.

[0162] As described above, in the circulating pump 1500, ink suction and discharge are performed by changing the pressure within the pump chamber 1503 through the deformation of the diaphragm 1506. At this time, even if the diaphragm 1506 shifts, the pressure change within the pump chamber 1503 will decrease due to the expansion and contraction of the bubbles when bubbles enter the pump chamber 1503 in a mixed manner, and therefore, the amount of ink delivered is reduced. Therefore, the pump chamber 1503 is arranged parallel to the direction of gravity, so that bubbles that have entered the pump chamber 1503 in a mixed manner may accumulate in the upper region of the pump chamber 1503, while the pump discharge port 1502 is arranged above the center of the pump chamber 1503. This improves the discharge of bubbles within the pump and thus allows for flow rate stabilization.

[0163] <Ink flow within the liquid ejector head>

[0164] Figures 19A to 19E Each diagram illustrates the flow of ink within a liquid ejector head. (See reference...) Figures 19A to 19E This describes the ink circulation process within the liquid ejector head 1000. To more clearly illustrate the ink circulation path, a simplified diagram is provided. Figures 19A to 19E The relative positions of each component (first pressure regulating unit 1120, second pressure regulating unit 1150, circulating pump 1500, etc.) are specified. Therefore, the relative positions of each component are related to those described later. Figure 27 Their structures are different. Figure 19A The diagram schematically illustrates the flow of ink during a printing operation performed by ejecting ink from the ejection port 1013. Figures 19A to 19E The arrows in the diagram indicate ink flow. In this embodiment, both the external pump 1021 and the circulation pump 1500 are initially driven when a printing operation is performed. The external pump 1021 and the circulation pump 1500 can be driven regardless of the printing operation. Furthermore, the external pump 1021 and the circulation pump 1500 do not necessarily need to be driven in a linked manner, and they can be driven independently.

[0165] During the printing operation, the circulation pump 1500 is in the on state (driven state), and ink flowing from the first pressure control chamber 1122 flows into the supply flow path 1130 and the bypass flow path 1160. The ink that has flowed into the supply flow path 1130 flows into the collection flow path 1140 after passing through the jet module 1300, and is then supplied to the second pressure control chamber 1152.

[0166] On the other hand, ink that has flowed from the first pressure control chamber 1122 into the bypass flow path 1160 flows into the second pressure control chamber 1152 via the second valve chamber 1151. Ink that has flowed into the second pressure control chamber 1152 flows back into the first pressure control chamber 1122 after passing through the pump inlet flow path 1170, the circulation pump 1500, and the pump outlet flow path 1180. At this time, based on the aforementioned Equation 2, the control pressure of the first valve chamber 1121 is set higher than the control pressure of the first pressure control chamber 1122. Therefore, the ink in the first pressure control chamber 1122 does not flow into the first valve chamber 1121, but is instead supplied to the jetting module 1300 again via the supply flow path 1130. Ink that has flowed into the jetting module 1300 flows back into the first pressure control chamber 1122 via the collection flow path 1140, the second pressure control chamber 1152, the pump inlet flow path 1170, the circulation pump 1500, and the pump outlet flow path 1180. Through the above, ink circulation is performed within the liquid ejector head 1000.

[0167] In the aforementioned ink circulation, the amount of ink circulating within the ejection module 1300 (flow rate) is determined by the pressure difference between the control pressure of the first pressure control chamber 1122 and the second pressure control chamber 1152. This pressure difference is then set such that the circulating ink amount is sufficient to suppress ink thickening near the ejection port within the ejection module 1300. Furthermore, ink corresponding to the ink consumed during printing is supplied from the ink cartridge 2 via the filter 1110 and the first valve chamber 1121 to the first pressure control chamber 1122. The mechanism for supplying ink corresponding to the consumed ink is explained in detail. By reducing the amount of ink corresponding to the ink consumed during printing within the circulation path, the pressure within the first pressure control chamber 1122 also decreases, and consequently, the amount of ink within the first pressure control chamber 1122 also decreases. Along with the reduction in ink within the first pressure control chamber 1122, the internal volume of the first pressure control chamber 1122 decreases. As the internal volume of the first pressure control chamber 1122 decreases, the communication port 1191A enters the open state, and ink is supplied from the first valve chamber 1121 to the first pressure control chamber 1122. During this supplied ink flow, a pressure loss occurs as it passes from the first valve chamber 1121 through the communication port 1191A, and the positive pressure ink is switched to a negative pressure state by the ink flowing into the first pressure control chamber 1122. Then, as ink flows from the first valve chamber 1121 into the first pressure control chamber 1122, the pressure within the first pressure control chamber 1122 increases, and the internal volume of the first pressure control chamber 1122 increases, and the communication port 1191A enters the closed state. As described above, the communication port 1191A repeatedly switches between the closed and open states according to ink consumption. Furthermore, when there is no ink consumption, the communication port 1191A remains in the closed state.

[0168] Figure 19B The diagram schematically illustrates the ink flow immediately following the completion of the printing operation and the shutdown (stopped) state of the circulation pump 1500. At the point when the printing operation is completed and the circulation pump 1500 is shut off, the pressures in the first pressure control chamber 1122 and the second pressure control chamber 1152 are the control pressures during the printing operation. Therefore, based on the pressure difference between the pressures in the first pressure control chamber 1122 and the second pressure control chamber 1152, the following occurs... Figure 19B The movement of ink is illustrated. Specifically, ink flow subsequently occurs, wherein ink is supplied from the first pressure control chamber 1122 to the ejection module 1300 via the supply flow path 1130, and thereafter, the ink reaches the second pressure control chamber 1152 via the collection flow path 1140. Furthermore, ink flow also subsequently occurs, wherein ink flows from the first pressure control chamber 1122 to the second pressure control chamber 1152 via the bypass flow path 1160 and the second valve chamber 1151.

[0169] The amount of ink that has moved from the first pressure control chamber 1122 to the second pressure control chamber 1152 via these ink flows is supplied from the ink cartridge 2 through the filter 1110 and the first valve chamber 1121 to the first pressure control chamber 1122. Therefore, the amount of contents within the first pressure control chamber 1122 remains constant. With the amount of contents within the first pressure control chamber 1122 constant, according to the aforementioned Equation 2, the spring force F1 of the valve spring 1200, the spring force F2 of the pressure regulating spring 1220, the pressure receiving area S1 of the valve 1190, and the pressure receiving area S2 of the press plate 1210 remain constant. Therefore, the pressure within the first pressure control chamber 1122 is determined based on the change in the pressure (gauge pressure) P1 within the first valve chamber 1121. Therefore, when the pressure P1 within the first valve chamber 1121 does not change, the pressure P2 within the first pressure control chamber 1122 remains the same as the control pressure during the printing operation.

[0170] On the other hand, the pressure within the second pressure control chamber 1152 changes over time according to the amount of contents accompanying the inflow of ink from the first pressure control chamber 1122. Specifically, in the process of... Figure 19B The state changes to such Figure 19C During the state shown (connection port 1191 is closed and the second valve chamber 1151 and the second pressure control chamber 1152 are not connected), the pressure in the second pressure control chamber 1152 changes according to Equation 2. Afterwards, the pressure plate 1210 and the valve shaft 1190a enter a state where they are not in contact with each other, and the connection port 1191 enters the closed state. Then, as... Figure 19D As shown, ink flows from the collection path 1140 into the second pressure control chamber 1152. Through this ink inflow, the pressing plate 1210 and the flexible member 1230 shift, and the pressure within the second pressure control chamber 1152 varies according to Equation 4 until the internal volume of the second pressure control chamber 1152 reaches its maximum. That is, the pressure increases.

[0171] In production Figure 19CIn the current state, ink flow from the first pressure control chamber 1122 to the second pressure control chamber 1152 via the bypass flow path 1160 and the second valve chamber 1151 ceases. Therefore, only the flow occurs where ink in the first pressure control chamber 1122 is supplied to the ejection module 1300 via the supply flow path 1130, and thereafter, ink reaches the second pressure control chamber 1152 via the collection flow path 1140. As previously described, ink movement from the first pressure control chamber 1122 to the second pressure control chamber 1152 occurs based on the pressure difference between the pressure in the first pressure control chamber 1122 and the pressure in the second pressure control chamber 1152. Therefore, ink movement ceases when the pressure in the second pressure control chamber 1152 becomes equal to the pressure in the first pressure control chamber 1122.

[0172] Furthermore, when the pressure in the second pressure control chamber 1152 becomes equal to the pressure in the first pressure control chamber 1122, the second pressure control chamber 1152 expands to... Figure 19D The state shown. In the second pressure control chamber 1152 as... Figure 19D In the expanded configuration shown, a reservoir portion capable of storing ink is formed in the second pressure control chamber 1152. It takes approximately one to two minutes for the cycle pump 1500 to transition from a stopped state to a working state. Figure 19D The state within, although time may vary depending on the shape and size of the flow path and the nature of the ink. Figure 19D When the circulating pump 1500 is driven while the ink is stored in the reservoir section, the ink in the reservoir section is supplied to the first pressure control chamber 1122 via the circulating pump 1500. Thus, as shown... Figure 19E As shown, the amount of ink in the first pressure control chamber 1122 increases, and the flexible member 1230 and the pressing plate 1210 shift along the expansion direction. Then, with the circulation pump 1500 continuing to drive, the state within the circulation path changes. Figure 19A The state shown.

[0173] In the above explanation, Figure 19A An example was given during a printing operation, but as mentioned before, ink cycling can be performed without a printing operation. Similarly, in this case, as... Figures 19A to 19E The flow of ink shown occurs according to the driving and stopping of the circulation pump 1500.

[0174] Furthermore, as described above, in this embodiment, an example is used where the communication port 1191B in the second pressure regulating unit 1150 is in an open state when the circulation pump 1500 is driven and ink circulation is performed, and in a closed state when ink circulation stops; however, this example is not limited to this. The control pressure can also be set such that the communication port 1191B in the second pressure regulating unit 1150 remains in a closed state even when the circulation pump 1500 is driven and ink circulation is performed. The function of the bypass flow path 1160 will be explained in detail below.

[0175] The bypass flow path 1160 connecting the first pressure regulating unit 1120 and the second pressure regulating unit 1150 is configured to prevent the ejection module 1300 from being affected, for example, if the negative pressure occurring within the circulation path becomes higher than a predetermined value. Furthermore, the bypass flow path 1160 is also configured to supply ink to the pressure chamber 1012 from both sides of the supply flow path 1130 and the collection flow path 1140.

[0176] First, an example will be given where the ejection module 1300 is unaffected by the bypass flow path 1160 when the negative pressure becomes higher than a predetermined value. For example, there may be cases where the properties of the ink (e.g., viscosity) change during ambient temperature variations. When the ink viscosity changes, the pressure loss within the circulation path also changes. For example, when the ink viscosity decreases, the amount of pressure loss within the circulation path also decreases. As a result, the flow rate of the circulation pump 1500, driven by a predetermined drive amount, increases, and the flow rate of the ink flowing through the ejection module 1300 increases. On the other hand, the ejection module 1300 is maintained at a predetermined temperature by a temperature control mechanism (not shown schematically), and therefore, even if the ambient temperature changes, the viscosity of the ink within the ejection module 1300 remains constant. When the flow rate of the ink flowing within the ejection module 1300 increases while the viscosity of the ink within the ejection module 1300 remains constant, the negative pressure in the ejection module 1300 increases accordingly due to flow resistance. If the negative pressure in the injection module 1300 becomes higher than a predetermined value as described above, there is a concern that the meniscus of the injection port 1013 may be damaged and external air may be drawn into the circulation path, thus preventing normal injection from being performed. Furthermore, there is a concern that the negative pressure in the pressure chamber 1012 may become higher than a predetermined value, affecting injection even if the meniscus is not damaged.

[0177] Therefore, in this embodiment, a bypass flow path 1160 is formed within the circulation path. By providing the bypass flow path 1160, ink also flows into the bypass flow path 1160 when the negative pressure becomes higher than a predetermined value, and thus, the pressure within the ejection module 1300 can be kept constant. Therefore, for example, the communication port 1191B in the second pressure regulating unit 1150 can also be configured to have a control pressure that remains closed even when the circulation pump 1500 is being driven. Then, the control pressure in the second pressure regulating unit 1150 can also be set such that the communication port 1191B in the second pressure regulating unit 1150 enters the open state when the negative pressure becomes higher than a predetermined value. That is, assuming that even if the pump flow rate changes due to viscosity changes (e.g., environmental changes), the meniscus does not break or maintain a predetermined negative pressure, the communication port 1191B can be in the closed state when the circulation pump 1500 is being driven.

[0178] <Construction of the jet unit>

[0179] Figure 20A and Figure 20B Each is a schematic diagram illustrating the circulation path of ink corresponding to a color in the jetting unit 1003 of this embodiment. Figure 20A This is an exploded perspective view of the spray unit 1003 as seen from the side of the first support member 1004. Figure 20B This is an exploded perspective view of the injection unit 1003 as seen from the injection module 1300 side. Figure 20A and Figure 20B In the diagram, the in and out arrows indicate the flow of ink, and the ink flow is described only for one color, but the flow is the same for other colors. Furthermore, in... Figure 20A and Figure 20B The description of the second support member and the electrical wiring member is omitted here, and this is the same as the description of the construction of the spraying unit below. The spraying module 1300 includes a spraying element substrate 1340 and an opening plate 1330. Figure 21 The diagram shows the opening plate 1330, and Figure 22 This is a diagram showing the jetting element substrate 1340.

[0180] Ink is supplied from circulation unit 200 to ejection unit 1003 via a connector member (not shown schematically). The path of the ink after passing through the connector member until it returns to the connector member is explained.

[0181] The ejection module 1300 includes an ejection element substrate 1340 and an opening plate 1330, and also includes an ejection port forming member 1320. The ejection element substrate is a silicon substrate 1310. The ejection element substrate 1340, the opening plate 1330, and the ejection port forming member 1320 are formed by overlapping and connecting each ink flow path to communicate with each other, and are supported by a first support member 1004. By supporting the ejection module 1300 by the first support member 1004, an ejection unit 1003 is formed. The ejection element substrate 1340 includes the ejection port forming member 1320, and the ejection port forming member 1320 includes a plurality of ejection port rows, in which a plurality of ejection ports 1013 form a row and eject a portion of the ink supplied via the ink flow path within the ejection module 1300 from the ejection ports 1013. Unejected ink is collected via the ink flow path within the ejection module 1300.

[0182] like Figure 20A , Figure 20B and Figure 21 As shown, the opening plate 1330 includes multiple arrays of ink supply ports 1311 and multiple arrays of ink collection ports 1312. (As...) Figure 22 As shown in Figure 23, the jetting element substrate 1340 includes multiple arrays of supply connection flow paths 1323 and multiple arrays of collection connection flow paths 1324. Furthermore, the jetting element substrate 1340 includes a common supply flow path 1018 communicating with the multiple supply connection flow paths 1323 and a common collection flow path 1019 communicating with the multiple collection connection flow paths 1324. An ink flow path within the jetting unit 1003 is formed by communicating the ink supply flow path 1048 and the ink collection flow path 1049 disposed in the first support member 1004 with the flow path disposed in the jetting module 1300. The support member supply port 1211 is a cross-sectional opening forming the ink supply flow path 1048, and the support member collection port 1212 is a cross-sectional opening forming the ink collection flow path 1049.

[0183] Ink supplied to the jetting unit 1003 is supplied from the circulation unit 200 side to the ink supply flow path 1048 of the first support member 1004. Ink that has already flowed via the support member supply port 1211 within the ink supply flow path 1048 is supplied via the ink supply flow path 1048 and the ink supply port 1311 of the opening plate 1330 to the common supply flow path 1018 of the jetting element substrate 1340, and enters the supply connection flow path 1323. The flow path up to the supply connection flow path 1323 is on the supply side. Then, the ink flows via the pressure chamber 1012 of the jetting port forming member 1320 to the collection connection flow path 1324 on the collection side. Details of the ink flow in the pressure chamber 1012 will be described later.

[0184] The ink that has entered the collection connection flow path 1324 in the flow path on the collection side flows to the common collection flow path 1019. Then, the ink flows from the common collection flow path 1019 through the ink collection port 1312 of the opening plate 1330 to the ink collection flow path 1049 of the first support member 1004, and is collected by the circulation unit 200 through the support member collection port 1212.

[0185] The area in the opening plate 1330 where the ink supply port 1311 and the ink collection port 1312 are absent corresponds to the area in the first support member 1004 used to separate the support member supply port 1211 and the support member collection port 1212. Furthermore, the first support member 1004 also has no opening in this area. Such an area serves as an adhesion area, for example, when the jetting module 1300 and the first support member 1004 are adhered to each other.

[0186] exist Figure 21 In the opening plate 1330, multiple columns of multiple openings arranged in the Y direction and the X direction are provided, and openings for supply (in) and openings for collection (out) are alternately arranged in the Y direction, such that the openings for in and the openings for out are offset from each other by half a spacing in the X direction. Figure 22 In this design, on the jetting element substrate 1340, a common supply flow path 1018 communicating with a plurality of supply connection flow paths 1323 arranged in the Y direction and a common collection flow path 1019 communicating with a plurality of collection connection flow paths 1324 arranged in the Y direction are alternately arranged in the X direction. Each of the common supply flow paths 1018 and the common collection flow path 1019 is divided for each type of ink, and the number of common supply flow paths 1018 and the number of common collection flow paths 1019 to be arranged are determined according to the number of jetting port columns for each color. Furthermore, the supply connection flow paths 1323 and the collection connection flow paths 1324 are also arranged such that their number corresponds to the number of jetting ports 1013. This arrangement is not necessarily performed in a one-to-one manner, and one supply connection flow path 1323 and one collection connection flow path 1324 can also be arranged to correspond to a plurality of jetting ports 1013.

[0187] By overlapping and connecting, for example, an opening plate 1330 and a jetting element substrate 1340, the flow paths of each ink are made interconnected, forming a jetting module 1300, which is supported by a first support member 1004. Thus, an ink flow path is formed, including a supply flow path and a collection flow path as described above.

[0188] Figures 23A to 23C Each is a cross-sectional view showing the ink flow in different parts of the jetting unit 1003. Figure 23A yes Figure 20AThe cross-sections shown in XXIIIa-XXIIIa are illustrated, and a cross-section of the portion in the ink supply flow path 1048 and the ink supply port 1311 that are connected to each other in the jetting unit 1003 is also shown. Additionally, Figure 23B yes Figure 20A The cross-sections shown in XXIIIb-XXIIIb are illustrated, and a cross-section of the portion in the ink collection path 1049 and the ink collection port 1312 in the jetting unit 1003 that are connected to each other is also shown. Furthermore, Figure 23C yes Figure 20A The cross-section shown in XXIIIc-XXIIIc shows the portion of the ink supply port 1311 and ink collection port 1312 that is not connected to the flow path of the first support member 1004.

[0189] In the ink supply path, such as Figure 23A As shown, ink is supplied from the portion where the ink supply flow path 1048 of the first support member 1004 and the ink supply port 1311 of the opening plate 1330 overlap and communicate with each other. Furthermore, in the ink collection flow path, as... Figure 23B As shown, ink is collected from the portion where the ink collection path 1049 of the first support member 1004 and the ink collection port 1312 of the opening plate 1330 overlap and communicate with each other. Furthermore, as... Figure 23C As shown, in the jetting unit 1003, there are areas in which openings are partially not provided in the opening plate 1330. In such areas, for example, ink is not supplied or collected between the jetting element substrate 1340 and the first support member 1004. Figure 23A Ink is supplied to the area shown, which is equipped with ink supply port 1311, and in the area shown, ink is supplied to the area shown ... which is equipped with ink supply port 1311. Figure 23B The area shown has an ink collection port 1312 for collecting ink. In this embodiment, a configuration using an opening plate 1330 is illustrated as an example, but aspects without the opening plate 1330 are acceptable. For example, a configuration in which flow paths corresponding to the ink supply flow path 1048 and the ink collection flow path 1049 are formed on the first support member 1004, and the jetting element substrate 1340 is connected to the first support member 1004.

[0190] Figure 24A and Figure 24B Each is a cross-sectional view showing the vicinity of the injection port 1013 in the injection module 1300. Figure 24A and Figure 24BThe thick arrows shown in the common supply flow path 1018 and common collection flow path 1019 indicate the oscillation of ink in the use of the serial liquid jetting device 2000. Ink supplied to the pressure chamber 1012 via the common supply flow path 1018 and the supply connection flow path 1323 is ejected from the jet port 1013 through the driven jetting element 1015. When the jetting element 1015 is not driven, ink is collected from the pressure chamber 1012 into the common collection flow path 1019 via the collection connection flow path 1324, which serves as the collection flow path.

[0191] When performing the above-described cycle of ink ejection using the serial liquid ejection device 2000, the ink ejection is significantly affected by the oscillation of ink within the ink flow path caused by the main scanning of the liquid ejection head 1000. Specifically, the effect of the oscillation of ink within the ink flow path manifests as differences in the amount of ink ejected and deviations in the ejection direction.

[0192] Therefore, the design is such that both the common supply flow path 1018 and the common collection flow path 1019 in this embodiment are also... Figure 24A and Figure 24B The cross-section shown extends in the Z direction perpendicular to the X direction (main scanning direction) and also extends in the Y direction. By designing a structure such as this, the width of each flow path of the common supply flow path 1018 and the common collection flow path 1019 in the main scanning direction can be reduced. The width of each flow path of the common supply flow path 1018 and the common collection flow path 1019 in the main scanning direction is reduced. Therefore, the inertial force of the ink applied in the opposite direction to the main scanning direction and acting within the common supply flow path 1018 and the common collection flow path 1019 during the main scan ( Figure 24A and Figure 24B The ink oscillation caused by the thick black arrow in the image is reduced. This suppresses the impact of ink oscillation on ink ejection. Furthermore, by extending the common supply flow path 1018 and the common collection flow path 1019 in the Z direction, the cross-sectional area is increased, and the flow path pressure loss is reduced.

[0193] As described above, this configuration reduces ink wobbling within the common supply flow path 1018 and common collection flow path 1019 during the main scan by reducing the width of each flow path in the main scan direction. However, this does not mean that wobbling is completely eliminated. Therefore, in this embodiment, the configuration is designed such that the common supply flow path 1018 and common collection flow path 1019 are arranged at their overlapping positions in the X direction to suppress jetting differences for each type of ink, which may still occur due to the reduced wobbling.

[0194] As described above, in this embodiment, the supply connection flow path 1323 and the collection connection flow path 1324 are correspondingly arranged with respect to the ejection port 1013, and the correspondence is such that the supply connection flow path 1323 and the collection connection flow path 1324 are arranged side by side in the X direction, with the ejection port 1013 sandwiched between the supply connection flow path and the collection connection flow path. Therefore, there are portions in the X direction where the common supply flow path 1018 and the common collection flow path 1019 do not overlap, and if the correspondence in the X direction between the supply connection flow path 1323 and the collection connection flow path 1324 is disrupted, the ink flow and ejection in the X direction within the pressure chamber 1012 are affected. With the further increase in the influence of ink oscillation, there is a concern that the ink ejection at each ejection port may be further affected.

[0195] Therefore, the common supply flow path 1018 and the common collection flow path 1019 are arranged at a position where they overlap in the X direction. Consequently, at any position where the injection ports 1013 are arranged in the Y direction, the degree of ink oscillation in the common supply flow path 1018 and the degree of ink oscillation in the common collection flow path 1019 are substantially equal. As a result, the pressure difference between the common supply flow path 1018 side and the common collection flow path 1019 side occurring within the pressure chamber 1012 does not change significantly, and therefore, stable injection can be performed.

[0196] Furthermore, in some liquid ejector heads that circulate ink, the flow path supplying ink to the liquid ejector head and the flow path collecting ink are constructed using the same flow path. However, in this embodiment, the common supply flow path 1018 and the common collection flow path 1019 are separate flow paths. Then, the supply connection flow path 1323 and the pressure chamber 1012 are in communication with each other, and the pressure chamber 1012 and the collection connection flow path 1324 are in communication with each other, and ink is ejected from the ejection port 1013 of the pressure chamber 1012. That is, this configuration ensures that the pressure chamber 1012 connecting the supply connection flow path 1323 and the collection connection flow path 1324 includes the ejection port 1013. Therefore, ink flow from the supply connection flow path 1323 side to the collection connection flow path 1324 side is generated in the pressure chamber 1012, and thus, the ink within the pressure chamber 1012 circulates efficiently. By effectively circulating the ink within the pressure chamber 1012, the ink within the pressure chamber 1012 can be kept fresh, and freshness facilitates the evaporation of the ink from the ejection port 1013.

[0197] Furthermore, the two flow paths—a common supply flow path 1018 and a common collection flow path 1019—connected to the pressure chamber 1012, enable ink to be supplied from both flow paths when high-flow-rate jetting is required. That is, compared to a configuration that performs ink supply and collection via only one flow path, the configuration of this embodiment not only has the advantage of efficiently performing cycles but also the advantage of being able to handle high-flow-rate jetting.

[0198] Furthermore, with the common supply flow path 1018 and the common collection flow path 1019 arranged close to each other in the X direction, the effects of ink oscillation are less likely to occur. It is desirable that the flow paths be configured such that the distance between them is 75 μm to 100 μm.

[0199] Figure 25 This is a diagram showing the jetting element substrate 1340 as a comparative example. Figure 25 The descriptions of the supply connection flow path 1323 and the collection connection flow path 1324 are omitted here. Ink that has received heat energy through the jetting element 1015 in the pressure chamber 1012 flows into the common collection flow path 1019, and therefore, the ink flow has a temperature relatively higher than that of the ink in the common supply flow path 1018. In this comparative example, as... Figure 25 The α portion, surrounded by a single-dot dashed line, exists in a portion of the spray element substrate 1340 in the X direction where only the common collection flow path 1019 exists. In this case, the temperature locally rises at this portion, and temperature non-uniformity occurs within the spray module 1300, thus potentially affecting the spraying process.

[0200] Ink with a relatively lower temperature than the common collection flow path 1019 flows through the common supply flow path 1018. Therefore, when the common supply flow path 1018 and the common collection flow path 1019 are adjacent to each other, a portion of the temperature between the common supply flow path 1018 and the common collection flow path 1019 near their adjacency is offset, thus suppressing temperature rise. Therefore, it is preferable that the common supply flow path 1018 and the common collection flow path 1019 have substantially the same length, exist at their overlapping location, and are adjacent to each other.

[0201] Figure 26A and Figure 26B Each diagram illustrates the flow path configuration of a liquid ejector head 1000 compatible with cyan (C), magenta (M), and yellow (Y) inks. In the liquid ejector head 1000, as... Figure 26A As shown, a circulation path is set for each type of ink. The pressure chamber 1012 is positioned along the X direction (main scanning direction) of the liquid ejector head 1000. Furthermore, as... Figure 26BAs shown, the common supply flow path 1018 and the common collection flow path 1019 are arranged along the column of injection ports in which the injection ports 1013 are arranged, and the common supply flow path 1018 and the common collection flow path 1019 are arranged to extend in the Y direction to sandwich the column of injection ports in the middle.

[0202] <Connection between the main body and the liquid injection head>

[0203] Figure 27 This is a schematic structural diagram showing in detail the ink cartridge disposed in the main body of the liquid jetting device 2000 of this embodiment, the connection state between the external pump 1021 and the liquid jetting head 1000, the arrangement of the circulation pump, etc. The liquid jetting device 2000 of this embodiment has a structure that allows for easy replacement of the liquid jetting head 1000 with another liquid jetting head in the event of a malfunction in the liquid jetting head 1000. Specifically, the liquid jetting device 2000 has a liquid connection portion 1700, which allows for easy connection and disconnection between the ink supply pipe 1059 connected to the external pump 1021 and the liquid jetting head 1000. Thus, it is possible to easily attach and detach the liquid jetting head 1000 from the liquid jetting device 2000.

[0204] like Figure 27 As shown, the liquid connection portion 1700 has a liquid connector insertion port 1053a protruding from the head housing 1053 of the liquid ejector head 1000 and a cylindrical liquid connector 1059a into which the liquid connector insertion port 1053a can be inserted. The liquid connector insertion port 1053a is fluidly connected to the ink supply flow path formed within the liquid ejector head 1000 and is connected to the first pressure regulating unit 1120 via the previously described filter 1110. Furthermore, the liquid connector 1059a is located at the end of the ink supply pipe 1059 connected to an external pump 1021, which supplies ink from the ink cartridge 2 to the liquid ejector head 1000 under pressure.

[0205] As described above, the liquid connection portion 1700 allows for easy... Figure 27 The attached, detached, and replaced liquid jet head 1000 is shown. However, if the sealing of the liquid connector insertion port 1053a and liquid connector 1059a is reduced, there is a concern that ink pressurized and supplied by the external pump 1021 may leak from the liquid connection portion 1700. If leaked ink adheres to the circulation pump 1500, etc., a malfunction may occur in the electrical system. Therefore, in this embodiment, the circulation pump, etc., is arranged as follows.

[0206] Arrangement of circulating pumps, etc.

[0207] like Figure 27 As shown, in this embodiment, to prevent ink that has leaked from the liquid connection portion 1700 from adhering to the circulation pump 1500, the circulation pump 1500 is arranged above the liquid connection portion 1700 in the upward direction of gravity. That is, the circulation pump 1500 is arranged above the liquid connector insertion port 1053a (which serves as the liquid inlet port for the liquid jet head 1000) in the upward direction of gravity. Furthermore, the circulation pump 1500 is arranged at a position where it does not contact the components constituting the liquid connection portion 1700. Thus, even if ink leaks from the liquid connection portion 1700, the ink will flow in the horizontal direction (the direction of the opening of the liquid connector 1059a) or in the downward direction of gravity, and therefore, it is possible to suppress ink from reaching the circulation pump 1500 located in the upward direction of gravity. In addition, the circulation pump 1500 is arranged at a position away from the liquid connection portion 1700, and therefore, the possibility of ink reaching the circulation pump 1500 through this component is also reduced.

[0208] Furthermore, the electrical connection portion 1515, which electrically connects the circulation pump 1500 and the electrical contact substrate 1006 via the flexible wiring member 1514, is positioned in the upward direction of gravity. Therefore, the possibility of electrical failure due to ink from the liquid connection portion 1700 can be reduced.

[0209] Furthermore, in this embodiment, a wall portion 1052b of the head housing 1053 is provided, and therefore, even if ink is ejected from the opening 1059b of the liquid connection portion 1700, the ink can be cut off and the possibility of ink reaching the circulation pump 1500 and the electrical connection portion 1515 can be reduced.

[0210] Although the invention has been described with reference to exemplary embodiments, it should be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the appended claims should be given the broadest interpretation to cover all such modifications and equivalent structures and functions.

Claims

1. A liquid injection head, comprising: A printing element having an ejection port configured to eject liquid, an ejection element configured to generate pressure to eject liquid from the ejection port, a plurality of pressure chambers that cause pressure generated by the drive of the ejection element to act on the liquid, a plurality of common supply flow paths communicating with the plurality of pressure chambers, and a plurality of common collection flow paths communicating with the plurality of pressure chambers. A circulation pump creates a pressure difference between the common supply flow path and the common collection flow path, such that liquid is supplied from the common supply flow path to the plurality of pressure chambers and collected from the plurality of pressure chambers into the common collection flow path; as well as A support member having distribution channels configured to distribute liquid into multiple common supply channels, and the support member supporting a printing element substrate. A common supply flow path opening is formed in the printed element substrate, through which liquid dispensed from the distribution flow path enters the common supply flow path. The support member has a distribution flow path opening formed on a side opposite to the common supply flow path opening. Wherein, the opening area of ​​the distribution flow path is larger than the opening area of ​​the common supply flow path, and In the operational state of the liquid injection head, the distribution flow path has an inner wall that is inclined relative to the direction of gravity.

2. The liquid injection head according to claim 1, wherein... The opening area of ​​the distribution flow path is more than twice the opening area of ​​the common supply flow path.

3. The liquid injection head according to claim 1, wherein... The angle formed by the normal vector of the inner wall of the flow path and the gravity direction vector is greater than or equal to 15 degrees.

4. The liquid injection head according to claim 1, wherein... Multiple distribution flow paths are formed in the support member.

5. The liquid injection head according to claim 4, wherein... The multiple distribution paths are arranged side by side along the direction in which the common supply path extends.

6. The liquid injection head according to claim 5, further comprising: A first bubble storage flow path distributes liquid to the plurality of distribution flow paths.

7. The liquid injection head according to claim 6, wherein The cross-sectional area of ​​the first bubble storage flow path in the ink circulation direction is more than 20 times the opening area of ​​the distribution flow path opening.

8. The liquid injection head according to claim 1, wherein The support member has a collection channel for collecting liquid from the plurality of common collection channels.

9. The liquid injection head according to claim 8, wherein A common collection flow path opening is formed in the printed element substrate, and liquid collected in the collection flow path is ejected from the common collection flow path through the common collection flow path opening. in, A collection flow path opening is formed in the support member, and the collection flow path opening is formed on the side opposite to the side of the common collection flow path opening. The opening area of ​​the collection flow path is larger than the opening area of ​​the common collection flow path.

10. The liquid injection head according to claim 9, wherein Multiple collection flow paths are formed in the support member.

11. The liquid injection head according to claim 10, wherein The multiple collection paths are arranged side by side along the direction in which the common collection path extends.

12. The liquid injection head according to claim 11, further comprising: A second bubble storage flow path collects liquid from the plurality of collection flow paths.

13. A liquid injection head, comprising: A printing element having an ejection port configured to eject liquid, an ejection element configured to generate pressure to eject liquid from the ejection port, a plurality of pressure chambers that cause pressure generated by the drive of the ejection element to act on the liquid, a plurality of common supply flow paths communicating with the plurality of pressure chambers, and a plurality of common collection flow paths communicating with the plurality of pressure chambers. A circulation pump creates a pressure difference between the common supply flow path and the common collection flow path, causing liquid to be supplied from the common supply flow path to the plurality of pressure chambers and collected from the plurality of pressure chambers into the common collection flow path. A support member having multiple distribution channels configured to distribute liquid into multiple common supply channels, and the support member supporting a printing element substrate. A first bubble storage flow path distributes liquid to the plurality of distribution flow paths. The distribution flow path includes a distribution flow path opening connected to the first bubble storage flow path. Wherein, the cross-sectional area of ​​the first bubble storage flow path in the ink circulation direction is greater than the opening area of ​​the distribution flow path opening.

14. The liquid injection head according to claim 13, wherein The cross-sectional area of ​​the first bubble storage flow path in the ink circulation direction is more than twice the opening area of ​​the distribution flow path opening.

15. The liquid injection head according to claim 14, wherein... The cross-sectional area of ​​the first bubble storage flow path in the ink circulation direction is more than 20 times the opening area of ​​the distribution flow path opening.

16. The liquid injection head according to claim 13, wherein The support member has multiple collection channels formed to collect liquid from the multiple common collection channels.

17. The liquid injection head according to claim 16, wherein... The plurality of collection flow paths are formed in the support member, and The multiple collection paths are arranged side by side along the direction in which the common collection path extends.

18. The liquid injection head according to claim 17, further comprising: A second bubble storage flow path collects liquid from the plurality of collection flow paths.

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