Liquid discharge head

Abstract

A liquid discharge head is provided, which can reduce waste liquid while prohibiting an increase in the size of the device. The liquid discharge head (20) includes: a pressure chamber (22) connected to a nozzle (21) from which liquid is discharged; an actuator (40) configured to apply discharge pressure to the liquid in the pressure chamber (22); a first supply channel (24a) connected to the pressure chamber (22) and through which a first liquid is supplied to the pressure chamber (22); a second supply channel (24b) connected to the pressure chamber (22) and through which a second liquid different from the first liquid is supplied to the pressure chamber (22); a first valve (50a) provided in the first supply channel (24a) and opened and closed by the first valve; and a second valve (50b) provided in the second supply channel (24b) and opened and closed by the second valve.

Description

Technical Field

[0001] The present disclosure relates to a liquid discharge head. Background Art

[0002] As an existing liquid discharge head, a piezoelectric inkjet head is known and described in Patent Document 1. The inkjet head includes: a nozzle from which an ink composition containing a pigment is discharged; a pressure chamber for applying pressure to the ink composition so that the ink composition is discharged from the nozzle; and a connecting portion for connecting the pressure chamber and the nozzle. An image is formed on a recording medium by the ink composition discharged from the nozzle.

[0003] Reference List

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2017-185676 Summary of the invention

[0006] Technical issues

[0007] There is a demand for an industrial printing device that discharges various liquids such as an ink composition containing a pigment, like the nozzle described in Patent Document 1. However, providing a dedicated nozzle for each liquid increases the size of the device. On the other hand, if the tank connected to the nozzle is replaced according to the liquid to be discharged, the residual liquid needs to be discarded so as to prohibit the residual liquid from mixing with the new liquid in the nozzle. This wastes a large amount of liquid.

[0008] The present disclosure has been made to solve the above-mentioned problems, and an object of the present disclosure is to provide a liquid discharge head capable of reducing waste liquid while inhibiting an increase in the size of the apparatus.

[0009] Solution to the problem

[0010] According to one aspect of the present disclosure, a liquid discharge head includes: a pressure chamber, which is connected to a nozzle and discharges liquid from the nozzle; an actuator, which is configured to apply discharge pressure to the liquid in the pressure chamber; a first supply channel, which is connected to the pressure chamber and a first liquid is supplied to the pressure chamber through the first supply channel; a second supply channel, which is connected to the pressure chamber and a second liquid different from the first liquid is supplied to the pressure chamber through the second supply channel; a first valve, which is arranged in the first supply channel and the first supply channel is opened and closed by the first valve; and a second valve, which is arranged in the second supply channel and the second supply channel is opened and closed by the second valve.

[0011] Advantageous Effects of the Invention

[0012] The present disclosure has the above configuration, and has an effect of providing a liquid discharge head that reduces waste liquid while inhibiting an increase in the size of the apparatus.

[0013] The above objects, other objects, features and advantages of the present disclosure will become more apparent from the following detailed description of preferred embodiments with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 A liquid discharge apparatus including a liquid discharge head according to a first embodiment of the present application is schematically shown.

[0015] Figure 2 yes Figure 1 A cross-sectional view of a portion of the liquid discharge head in FIG. 1 taken in a cross section perpendicular to the up-down direction.

[0016] Figure 3A It is along Figure 2 A cross-sectional view taken along line AA of Figure 3B Shown by Figure 3A The first valve in the state where the first supply passage is opened.

[0017] Figure 4A is a cross-sectional view of a portion of a liquid discharge head according to a first modification example of the first embodiment of the present disclosure, taken in a cross section parallel to the up-down direction, and Figure 4B Shown by Figure 4A The first valve in the state where the first supply passage is opened.

[0018] Figure 5 is a cross-sectional view of a portion of a liquid discharge head according to a second modification example of the first embodiment of the present disclosure, taken in a cross section parallel to the up-down direction.

[0019] Fig. 6A is a cross-sectional view of a portion of a liquid discharge head according to a third modified example of the first embodiment of the present disclosure, taken in a cross section orthogonal to the up-down direction, and Figure 6B It is along Fig. 6A Cross-sectional view taken along line BB in FIG.

[0020] Figure 7 is a cross-sectional view of a portion of a liquid discharge head according to a fourth modification example of the first embodiment of the present disclosure, taken in a cross section parallel to the up-down direction.

[0021] Fig. 8A and Figure 8B is used to explain Figure 7 An explanatory diagram of a situation in which the first supply channel in FIG. 1 discharges the first liquid.

[0022] Fig.9A is a cross-sectional view of a portion of a liquid discharge head according to a fifth modification example of the first embodiment of the present disclosure, taken in a cross section orthogonal to the up-down direction, and Fig. 9B is along Fig.9A Cross-sectional view taken along line CC.

[0023] List of reference numerals:

[0024] 20: head; 21: nozzle; 22: pressure chamber; 23: connection opening; 23a: first connection opening (connection opening); 23b: second connection opening (connection opening); 23c: third connection opening (connection opening); 24: supply channel; 24a: first supply channel; 24b: second supply channel; 24c: third supply channel; 30: channel forming body; 34: recess; 40: actuator; 50: valve; 50a: first valve; 50b: second valve; 50c: third valve; 51: valve body; 51a: first valve body (valve body); 51b: second valve body (valve body); 51c: third valve body (valve body); 52: piezoelectric element (driving part) ; 52a: first piezoelectric element (piezoelectric element; driving part); 52b: second piezoelectric element (piezoelectric element; driving part); 52c: third piezoelectric element (piezoelectric element; driving part); 55: circumferential edge; 59: electrostatic element (driving part); 62: silicon coating film; 124: supply channel; 124a: first supply channel; 124b: second supply channel; 125: downstream part; 126: upstream part; 151: valve body; 155: circumferential edge; 224: supply channel; 224a: first supply channel; 224b: second supply channel; 224c: third supply channel; 250: check valve; 251: valve body; 252: piezoelectric element. DETAILED DESCRIPTION

[0025] Hereinafter, embodiments of the present disclosure are explained in detail with reference to the accompanying drawings.

[0026] (First embodiment)

[0027] <Structure of Liquid Discharging Device>

[0028] The liquid discharge device 10 including the liquid discharge head (hereinafter referred to as "head 20") according to the first embodiment of the present disclosure is a device for discharging liquid. Hereinafter, although an example in which the liquid discharge device 10 is applied to an inkjet printer (the inkjet printer discharges liquid such as ink) is described, the liquid discharge device 10 is not limited thereto.

[0029] like Figure 1As shown in , the liquid discharge device 10 adopts a line head system. The liquid discharge device 10 includes a platen 11, a conveyor 12, a head unit 13, a tank 14 and a controller 15, however, the liquid discharge device 10 is not limited to the line head system, and any other system such as a serial head system may be adopted.

[0030] The platen 11 is a flat member. A recording medium R such as paper is disposed on the upper surface of the platen 11 to determine the distance between the head 20 and the recording medium R. The conveyor 12 has, for example, two conveying rollers 12a and a conveying motor. The two conveying rollers 12a sandwich the platen 11 between them in the conveying direction. The central axes of the two conveying rollers 12a are orthogonal to the conveying direction so that they are parallel to each other. The two conveying rollers 12a are coupled to the conveying motor. Driving the conveying motor causes the conveying rollers 12a to rotate, thereby conveying the recording medium R on the platen 11 in the conveying direction.

[0031] The head unit 13 has a length not less than the length of the recording medium R in a direction orthogonal to the conveying direction (orthogonal direction). The head unit 13 is provided with heads 20, and the heads 20 are arranged in the orthogonal direction. Each head 20 includes a nozzle 21 and an actuator 40 ( Figure 3A and Figure 3B ). The nozzle 21 opens in the lower surface of each head 20. When the actuator 40 is driven, the meniscus formed in the opening of the nozzle 21 vibrates, and the liquid is discharged from the nozzle 21. The details of the head 20 are described below.

[0032] The tank 14 includes, for example, a first tank 14a, a second tank 14b, and a third tank 14c. Each tank 14 stores a different kind of liquid. The tank 14 is connected to the head 20 via a tube. The liquid can be exemplified by, for example, water-based pigment ink, printing pigment ink, water-based sublimation ink, reactive dye ink, acid dye ink, disperse dye ink, solvent ink, UV ink, latex ink, and cleaning liquid (cleaner).

[0033] The controller 15 includes: a computing unit such as a CPU; a memory such as a RAM and a ROM; and a driving unit such as an ASIC. The controller 15 is connected to various driver ICs and various sensors. In the controller 15, the CPU receives various requests and detection signals of the sensors. Then, the CPU causes the RAM to store various data, and outputs various execution instructions to the ASIC based on the program stored in the ROM. Based on the instructions, the ASIC controls the corresponding driver IC and performs operations corresponding thereto. This drives the head 20 and the conveyor 12.

[0034] For example, the controller 15 performs a liquid discharge operation by the head 20, a conveying operation of the recording medium R by the conveyor 12, and the like. In the discharge operation, liquid is discharged from the nozzle 21 by driving the actuator 40 of the head 20, and an image is formed on the recording medium R by using the liquid. In the conveying operation, the conveying motor of the conveyor 12 is driven to convey the recording medium R by a predetermined amount in the conveying direction. Therefore, during printing, an image is arranged on the recording medium R along the conveying direction.

[0035] <Header Structure>

[0036] like Figure 2 , Figure 3A and Figure 3B As shown in , each head 20 includes a channel forming body 30, an actuator 40 and a valve 50. The channel forming body 30 is a stack of plates. The plates include a nozzle plate 31, a first channel plate 32 and a vibration plate 33. The plates are stacked from below in the above order in the up-down direction. Individual channels are formed in the channel forming body 30, and these individual channels are arranged in a row in the arrangement direction. The side closer to the first channel plate 32 relative to the nozzle plate 31 is called the upper side, and the side opposite to the upper side is called the lower side. However, the configuration of the head 20 is not limited to this. The arrangement direction of the individual channels may be a direction intersecting (for example, orthogonal) with the up-down direction, and the arrangement direction is along the orthogonal direction ( Figure 1 ) or a direction inclined relative to the orthogonal direction.

[0037] Each individual channel has a nozzle 21, a pressure chamber 22, and a supply channel 24. The nozzle 21 passes through the nozzle plate 31 in the up-down direction. The front end of the nozzle 21 opens in the lower surface of the nozzle plate 31. The central axis of the nozzle 21 extends in the up-down direction. The nozzle 21 has, for example, a cylindrical shape or a truncated cone shape in which the diameter of the distal end (the end at the lower side) is smaller than the diameter of the proximal end (the end at the upper side).

[0038] The pressure chamber 22 passes through the first channel plate 32 in the up-down direction. The lower end of the pressure chamber 22 is covered by the nozzle plate 31, and the upper end of the pressure chamber 22 is covered by the vibration plate 33. For example, the pressure chamber 22 has a columnar shape, such as a cylindrical shape, and its central axis extends in the up-down direction. The pressure chamber 22 and the nozzle 21 are coaxially arranged. The center of the lower end of the pressure chamber 22 is connected to the proximal end of the nozzle 21.

[0039] The upstream end of the supply channel 24 is connected to the tank 14 via a pipe, a header, etc. The downstream end of the supply channel 24 is connected to the pressure chamber 22. The supply channel 24 includes a first supply channel 24a, a second supply channel 24b, and a third supply channel 24c. The first supply channel 24a is connected to the first tank 14a ( Figure 1) is connected. The first liquid is supplied from the first tank 14a to the pressure chamber 22 through the first supply channel 24a. The second supply channel 24b is connected to the second tank 14b ( Figure 1 The second liquid is supplied from the second tank 14b to the pressure chamber 22 through the second supply channel 24b. The third supply channel 24c is connected to the third tank 14c ( Figure 1 ). The third liquid is supplied from the third tank 14c to the pressure chamber 22 through the third supply channel 24c. The flow rate of each liquid in each channel is, for example, 2 L / min.

[0040] The first supply channel 24a, the second supply channel 24b, and the third supply channel 24c are connected to the pressure chamber 22 at regular intervals in the circumferential direction of the pressure chamber 22 having a cylindrical shape. The connection opening 23 is provided in the outer peripheral surface of the pressure chamber 22 so as to surround the central axis of the pressure chamber 22. The connection opening 23 has: a first connection opening 23a connected to the first supply channel 24a; a second connection opening 23b connected to the second supply channel 24b; and a third connection opening 23c connected to the third supply channel 24c.

[0041] Each supply channel 24 is formed by a recessed portion that is recessed from the lower surface of the first channel plate 32. The upper end of the supply channel 24 is covered by a portion that is included in the first channel plate 32 and is located at the upper side of the recessed portion, and the lower end of the supply channel 24 is covered by the nozzle plate 31. Therefore, the supply channel 24 is formed in the channel forming body 30 and is defined by the inner surface of the channel forming body 30. The lower surface of the supply channel 24 in the up-down direction is defined by the upper surface of the nozzle plate 31. Any other surface of the supply channel 24 other than the lower surface is defined by the inner surface (surface for defining the recessed portion) formed by the recessed portion that is recessed from the lower surface of the first channel plate 32. Therefore, the inner surface of the channel forming body 30 that defines the supply channel 24 is formed by the upper surface of the nozzle plate 31 and the inner surface of the first channel plate 32.

[0042] Each actuator 40 is an element for applying a discharge pressure to the liquid in the pressure chamber 22. For example, the actuator 40 is formed of a piezoelectric element, which includes a common electrode 41, a piezoelectric layer 42, and an individual electrode 43. The common electrode 41 covers the entire surface of the vibration plate 33 via an insulating film. The piezoelectric layer 42 is provided for each pressure chamber 22. The piezoelectric layer 42 is provided on the common electrode 41 to overlap with the pressure chamber 22. The individual electrode 43 is provided for each pressure chamber 22. The individual electrode 43 is provided on the piezoelectric layer 42. One actuator 40 is formed of an individual electrode 43, a common electrode 41, and a piezoelectric layer 42 (active portion) between the individual electrode 43 and the common electrode 41.

[0043] The common electrode 41 is always kept at ground potential. The individual electrodes 43 are electrically connected to a driver IC for the actuator. Figure 1 ) receives a control signal, the driver IC generates a drive signal (voltage signal) and applies the drive signal to the individual electrode 43. In response to the drive signal, the active portion of the piezoelectric layer 42 contracts in the planar direction together with the common electrode 41 and the individual electrode 43, and the vibration plate 33 deforms in cooperation with the actuator 40. That is, the vibration plate 33 deforms in a direction in which the volume of the pressure chamber 22 increases and decreases, thereby applying a discharge pressure to the pressure chamber 22, by which the liquid is discharged from the nozzle 21.

[0044] The valve 50 includes a first valve 50a, a second valve 50b and a third valve 50c. The first valve 50a is arranged in the first supply channel 24a to open and close the first supply channel 24a. The second valve 50b is arranged in the second supply channel 24b to open and close the second supply channel 24b. The third valve 50c is arranged in the third supply channel 24c to open and close the third supply channel 24c. Each valve 50 is arranged near the connecting opening 23, and the connecting opening 23 connects each supply channel 24 and the pressure chamber 22. For example, the interval between the valve 50 and the connecting opening 23 is smaller than the diameter or size of the supply channel 24, preferably smaller than the diameter of the nozzle 21.

[0045] The first valve 50a includes a first valve body 51a and a first piezoelectric element 52a, and the first piezoelectric element 52a is used to move the first valve body 51a. The second valve 50b includes a second valve body 51b and a second piezoelectric element 52b, and the second piezoelectric element 52b is used to move the second valve body 51b. The third valve 50c includes a third valve body 51c and a third piezoelectric element 52c, and the third piezoelectric element 52c is used to move the third valve body 51c. Each of the first valve body 51a, the second valve body 51b, and the third valve body 51c is referred to as a valve body 51 in some cases. Each of the first piezoelectric element 52a, the second piezoelectric element 52b, and the third piezoelectric element 52c is referred to as a piezoelectric element 52 in some cases.

[0046] The diameter or size of the valve body 51 is larger than the diameter or size of the connection opening 23. The valve body 51 can cover the connection opening 23. The valve body 51 has a pair of surfaces (a facing surface 53, an opposite surface 54) and a circumferential edge 55 (including, for example, a side edge or surface and a lower edge or surface). The valve body 51 is arranged so that the pair of surfaces are parallel to the up and down directions. The facing surface 53 faces the connection opening 23. The opposite surface 54 is arranged on the side opposite to the facing surface 53. The circumferential edge 55 is arranged between the facing surface 53 and the opposite surface 54. The circumferential edge 55 is arranged to be parallel to the extension direction of the supply channel 24.

[0047] The valve body 51 has a shape in which the circumferential edge 55 contacts the inner surface of the channel forming body 30 that defines the supply channel 24 when the valve body 51 closes the supply channel 24. The valve body 51 is formed of an elastic material. The elastic material is formed of a material that is durable to liquid, such as silicone. At least any one of the first valve body 51a, the second valve body 51b, and the third valve body 51c is formed of an elastic material. The present disclosure is not limited to the case where the entire valve body 51 is formed of an elastic material. A portion of the valve body 51 may be formed of an elastic material, such that, for example, the circumferential edge 55 of the valve body 51 is formed of an elastic material.

[0048] The piezoelectric element 52 is a driving part (driver) that moves the valve body 51. The piezoelectric element 52 includes a common electrode 56, a piezoelectric layer 57, and a separate electrode 58. The common electrode 56, the piezoelectric layer 57, and the separate electrode 58 have structures similar to the common electrode 41, the piezoelectric layer 42, and the separate electrode 43, respectively. The common electrode 56 is always maintained at the ground potential. The separate electrode 58 is electrically connected to the driver IC for the valve. The piezoelectric element 52 expands and contracts in the up and down directions by a drive signal from the driver IC for the valve.

[0049] like Figure 3A As shown in FIG. 1 , in a state where the piezoelectric element 52 is expanded, the circumferential edge 55 of the valve body 51 contacts the inner surface of the channel forming body 30, and the lower end of the circumferential edge 55 contacts the upper surface of the nozzle plate 31. In this case, the valve body 51 covers the connection opening 23 to block the flow of the liquid in the supply channel 24. On the other hand, as Figure 3B As shown in the figure, when the piezoelectric element 52 is in the contracted state, the lower end of the circumferential edge 55 of the valve body 51 is separated from the nozzle plate 31, thereby forming a space between the circumferential edge 55 of the valve body 51 and the inner surface of the channel forming body 30, so that the valve body 51 opens the connecting opening 23, allowing liquid to flow in the supply channel 24.

[0050] <Method of controlling liquid discharge device>

[0051] The liquid discharge device 10 performs printing by using, for example, a liquid containing a pigment (pigment ink) and a liquid containing a dye (dye ink). In this case, the first tank 14a stores the pigment ink, the second tank 14b stores the dye ink, and the third tank 14c stores the cleaning agent.

[0052] When printing with pigment ink, Figure 3AAs shown in FIG. 1 , the controller 15 drives the piezoelectric element 52 of each valve 50 to move each valve body 51 downward. In this case, all the connection openings 23 (the first connection opening 23a, the second connection opening 23b, and the third connection opening 23c) are closed by all the valves 50 (the first valve 50a, the second valve 50b, and the third valve 50c). The flow of the liquid in the first supply channel 24a, the second supply channel 24b, and the third supply channel 24c is blocked by the first valve body 51a, the second valve body 51b, and the third valve body 51c, respectively.

[0053] like Figure 3B As shown in , the controller 15 then drives the first piezoelectric element 52a to move the first valve body 51a upward. This opens the first connection opening 23a, and the first liquid flows from the first tank 14a to the first supply channel 24a, is supplied to the pressure chamber 22 via the first connection opening 23a, and flows from the pressure chamber 22 into the nozzle 21.

[0054] Here, the controller 15 drives the actuator 40 based on the obtained print data to change the volume of the pressure chamber 22. Thus, pressure is applied from the pressure chamber 22 to the first liquid in the nozzle 21 to discharge the first liquid from the nozzle 21. An image is printed on the recording medium R by the pigment ink as the discharged first liquid.

[0055] When printing by using pigment ink is changed to printing by using dye ink, the controller 15 drives the first piezoelectric element 52A to move the first valve body 51A downward, as shown in FIG. Figure 3A . This closes all the connection openings 23 (the first connection opening 23a, the second connection opening 23b, and the third connection opening 23c) through all the valves 50 (the first valve 50a, the second valve 50b, and the third valve 50c), respectively. In this state, the controller 15 drives the actuator 40 to discharge the first liquid remaining in the first supply channel 24a, the pressure chamber 22, and the nozzle 21 from the nozzle 21.

[0056] Then, the controller 15 drives the third piezoelectric element 52c to move the third valve body 51c upward. This opens the third connection opening 23c, and the third liquid from the third tank 14c flows through the third supply channel 24c, is supplied to the pressure chamber 22 via the third connection opening 23c, and flows from the pressure chamber 22 into the nozzle 21. After that, the controller 15 drives the third piezoelectric element 52c to move the third valve body 51c downward. Therefore, the third connection opening 23c is closed by the third valve 50c. The controller 15 drives the actuator 40 to discharge the third liquid from the nozzle 21. Therefore, the pressure chamber 22 and the nozzle 21 are cleaned with the cleaning agent as the third liquid.

[0057] Next, the controller 15 drives the second piezoelectric element 52b to move the second valve body 51b upward. This opens the second connection opening 23b, and the second liquid from the second tank 14b flows through the second supply channel 24b, is supplied to the pressure chamber 22 via the second connection opening 23b, and flows from the pressure chamber 22 into the nozzle 21.

[0058] Here, the controller 15 drives the actuator 40 based on the obtained print data to change the volume of the pressure chamber 22. Thus, pressure is applied from the pressure chamber 22 to the second liquid in the nozzle 21, so that the second liquid is discharged from the nozzle 21. An image is printed on the recording medium R by the dye ink discharged as the second liquid.

[0059] <Working Effect>

[0060] In the head 20, the supply channel 24 is connected to each pressure chamber 22. Each valve 50 is provided in a corresponding one of the supply channels 24. Since the supply channels 24 share the pressure chamber 22 and the actuator 40, it is possible to inhibit the size of the device (e.g., the liquid discharge device 10) from increasing. In addition, for example, when the liquid is changed from the first liquid to the second liquid, the first liquid remaining in the pressure chamber 22 is discarded by closing the first valve 50a and opening the second valve 50b. This reduces the amount of liquid discarded.

[0061] In the head 20, each valve 50 includes a valve body 51 and a piezoelectric element 52 that moves the valve body 51. By using the piezoelectric element 52 in the driving portion that moves the valve body 51, each supply channel 24 can be opened and closed by each valve 50 while inhibiting an increase in the size of the device (e.g., the liquid discharge device 10).

[0062] In the head 20, a cleaning agent is used as one of the plurality of liquids. Therefore, when the kind of liquid is changed, it is possible to clean the pressure chamber 22 and the nozzle 21 with the cleaning agent. This prohibits different kinds of liquids from being mixed, which prohibits clogging of the nozzle 21 caused by condensation, mixing of colors, and the like.

[0063] In the head 20, the peripheral edge 55 of the valve body 51 in contact with the inner surface of the channel forming body 30 is formed of an elastic material. Therefore, in a state where the connection opening 23 is closed by the valve 50, the elasticity of the elastic material causes the valve body 51 to deform along the inner surface of the channel forming body 30, and the peripheral edge 55 of the valve body 51 is in close contact with the inner surface. This inhibits the liquid from leaking from the supply channel 24 to the pressure chamber 22.

[0064] In the spray head 20, each valve 50 is arranged near a corresponding connection opening 23, so the amount of liquid to be discarded when the liquid type is changed can be reduced. In addition, since the cleaning range is narrow (only the pressure chamber 22 and the nozzle 21), the cleaning time can be shortened.

[0065] In addition, the nozzle 21 is provided in the head 20, and the valve 50 is provided in the supply channel 24 connected to the nozzle 21 via the pressure chamber 22. Therefore, the liquid can be supplied to the corresponding nozzle 21. Therefore, when the cleaning agent is used as the liquid, by controlling the opening / closing of the valve 50, the cleaning agent is supplied only to the clogged nozzle 21, so that the clogged nozzle 21 is cleaned. This reduces the wasteful consumption of the cleaning agent.

[0066] In the head 20, the pressure chamber 22 has a columnar or cylindrical shape. The first supply channel 24a, the second supply channel 24b, and the third supply channel 24c are connected to the pressure chamber 22 at regular intervals in the circumferential direction of the pressure chamber 22. Therefore, the actuator 40 applies equal or uniform pressure to the liquid from the upper side of the pressure chamber 22. Therefore, the direction in which the liquid is discharged from the nozzle 21 is less likely to deviate from the predetermined direction. In addition, bubbles are unlikely to remain or stay in the pressure chamber 22, thereby reducing discharge failures caused by bubbles.

[0067] <First Modification>

[0068] In the head 20 according to the first modification, each of the first valve 50a, the second valve 50b, and the third valve 50c includes a valve body 51 and an electrostatic element 59 that moves the valve body 51. Since the head 20 according to the first modification is the same or similar to the head 20 according to the first embodiment except for the element that moves the valve body 51, the description of the same or similar features is omitted.

[0069] The electrostatic element 59 is provided in the valve 50. The electrostatic element 59 is a driving part (driver) for moving the valve body 51. For example, an electrostatic microactuator is used as the electrostatic element 59. The electrostatic element 59 includes a fixed electrode 60 and a movable electrode 61. The fixed electrode 60 and the movable electrode 61 are formed by a conductive material. The fixed electrode 60 and the movable electrode 61 are arranged at intervals in a direction orthogonal to the up and down directions. The movable electrode 61 is arranged to be displaceable relative to the fixed electrode 60. The movable electrode 61 is connected to the valve body 51. The fixed electrode 60 is grounded. The movable electrode 61 is electrically connected to the controller 15. When the controller 15 applies a voltage from a driver IC to the movable electrode 61, the generated electrostatic force drives the movable electrode 61 to move the valve body 51 connected to the movable electrode 61 upward.

[0070] The connection opening 23 is opened and closed by moving the valve body 51 using the electrostatic element 59. The moving distance of the valve body 51 by using the electrostatic element 59 can be greater than that by using the piezoelectric element 52, and it is possible to inhibit an increase in the size of the head 20. Therefore, the valve 50 opens and closes the connection opening 23 more efficiently.

[0071] <Second Modification>

[0072] The head 20 according to the second modification includes a first valve body 151a, a second valve body 151b, and a third valve body 151c. Figure 5 As shown in FIG. 1 , in at least any one of the first valve body 151a, the second valve body 151b, and the third valve body 151c, the circumferential edge 155 in contact with the inner surface of the channel forming body 30 is formed by the silicon coating film 62. Except for the valve body 151, the head 20 of the second modification is the same as or similar to the head 20 of the first embodiment, and thus the description of the same or similar features is omitted.

[0073] Each valve body 151 includes a main body 63 and a silicon coating film 62. The main body 63 has a facing surface 53, an opposite surface 54 (arranged on the opposite side of the facing surface 53), and a side surface between the facing surface 53 and the opposite surface 54. The main body 63 is formed of a material that is durable to liquid. The side surface of the valve body 151 is coated with the silicon coating film 62, and the silicon coating film 62 forms a circumferential edge 155 of the valve body 151. The silicon coating film 62 is formed of a silicone resin that is durable to liquid. By coating the side surface of the main body 63 with the silicone resin, the silicon coating film 62 is arranged in the circumferential edge 155 of the valve body 151.

[0074] In the state where the connection opening 23 is closed by the valve 50, the silicon coating film 62 of the peripheral edge 155 of the valve body 151 contacts the inner surface of the channel forming body 30, in which case the silicon coating film 62 having elasticity deforms along the inner surface and the peripheral edge 155 of the valve body 151 is in close contact with the inner surface. Therefore, it is possible to inhibit the liquid from leaking from the supply channel 24 to the pressure chamber 22.

[0075] <Third Modification>

[0076] like Fig. 6A and Figure 6B As shown in , in the head 20 according to the third modification, a recess 34 is provided in the inner surface of the passage forming body 30, and a peripheral edge 55 of at least any one of the first valve body 51a, the second valve body 51b, and the third valve body 51c is fitted into the recess. Except for this, the head 20 according to the third modification is the same or similar to the head 20 according to the first embodiment, and therefore the description of the same or similar features is omitted.

[0077] The supply channel 24 is formed by a recessed portion recessed from the lower surface of the first channel plate 32. The lower surface of the first channel plate 32 is stacked on the upper surface of the nozzle plate 31. Therefore, the inner surface of the channel forming body 30 for defining the supply channel 24 is formed by the upper surface of the nozzle plate 31 and the inner surface (surface for defining the recessed portion) of the first channel plate 32 formed by the recessed portion. The recessed portion 34 recessed from the supply channel 24 is formed in the above-mentioned upper surface and inner surface.

[0078] The diameter or size of the portion included in the supply passage 24 and formed with the recess 34 is larger than the diameter or size of any other portion other than the portion, and is slightly larger than the diameter or size of the valve body 51. In the extending direction of the supply passage 24, the distance (size) between a pair of surfaces defining the recess 34 is slightly larger than the distance (thickness) between the facing surface 53 and the opposite surface 54 of the valve body 51. The pair of surfaces defining the recess 34 is formed by a surface facing the facing surface 53 of the valve body 51 and a surface facing the opposite surface 54 of the valve body 51.

[0079] As described above, the circumferential edge 55 of the valve body 51 fits in the recess 34 and the valve body 51 overlaps with the surface of the recess 34 defining the passage forming body 30 in the extending direction of the supply passage 24. Therefore, leakage of liquid from the supply passage 24 to the pressure chamber 22 can be inhibited.

[0080] <Fourth Modification>

[0081] In the head 20 according to the fourth modification, as Figure 7 As shown in FIG. 1 , at least any one of the first supply channel 124a, the second supply channel 124b, and the third supply channel 124c has a downstream portion 125 connected to the pressure chamber 22 and an upstream portion 126 communicating with the downstream portion 125. The valve provided in the supply channel 124 has a valve body 251 provided in the downstream portion 125 and a check valve 250 for prohibiting the liquid from flowing back from the downstream portion 125 to the upstream portion 126. Except for this, the head 20 according to the fourth modification is the same or similar to the head 20 according to the first embodiment, and therefore the explanation of the same or similar features is omitted.

[0082] Specifically, the supply channel 124 has an upstream portion 126 and a downstream portion 125. The upstream end of the upstream portion 126 is connected to the tank 14, and the downstream portion of the upstream portion 126 is bent into an inverted U-shape. This bent portion 127 extends upward toward the downstream side, extends along the extension direction of the supply channel 124, and then extends downward. The upstream end of the downstream portion 125 is connected to the downstream end of the upstream portion 126 via a connecting opening 128, and the downstream end of the downstream portion 125 is connected to the pressure chamber 22. Except for the bent portion 127, the downstream portion 125 and the upstream portion 126 are formed by a recessed portion recessed from the lower surface of the first channel plate 32. The bent portion 127 is formed by a recessed portion recessed from the upper surface of the first channel plate 32. Therefore, the bent portion 127 is covered by the vibration plate 33.

[0083] The check valve 250 is provided in the supply passage 124 having the upstream portion 126 and the downstream portion 125. The check valve 250 includes a valve body 251 and a piezoelectric element 252 that moves the valve body 251. The valve body 251 is provided in the downstream portion 125. The valve body 251 is provided near the communication opening 128 to open and close the communication opening 128. The facing surface 253 of the valve body 251 faces the communication opening 128. The piezoelectric element 252 is provided on the curved portion 127 of the supply passage 124 via the vibration plate 33, and the piezoelectric element 252 applies pressure to the liquid in the curved portion 127, and the pressure moves the valve body 251 to open and close the communication opening 128. The valve body 251 may be provided to face the connection opening 23. Also in this case, while prohibiting the backflow from the pressure chamber 22, the valve body 251 is moved by the pressure applied by the piezoelectric element 252 to open and close the connection opening 23.

[0084] In such Figure 7 In the standby state before liquid discharge shown in FIG, neither the actuator 40 nor the piezoelectric element 252 is driven, and pressure is not applied to the liquid in the pressure chamber 22 and the curved portion 127. In this case, the communication opening 128 is covered by the facing surface 253 of the valve body 251, and liquid pressure is applied to the opposite surface 254 of the valve body 251. The valve body 251 is thus pressed against the valve seat 36. This causes the check valve 250 to close the supply passage 124, thereby prohibiting the liquid from flowing back from the pressure chamber 22 to the supply passage 124.

[0085] When the first liquid flowing from the first supply channel 124a is discharged from the nozzle 21, the actuator 40 is first driven to reduce the volume of the pressure chamber 22, such as Fig. 8A This applies pressure to the first liquid in the nozzle 21 via the pressure chamber 22 , and the first liquid is discharged from the nozzle 21 .

[0086] Then, if Figure 8BAs shown in , the actuator 40 is driven to restore the pressure chamber 22 to the original volume, and the first piezoelectric element 252a is driven to reduce the volume of the curved portion 127 of the first supply channel 124a. This causes the valve body 251 of the first valve 250a to separate from the valve seat 36, thereby opening the communication opening 128 of the first supply channel 124a. Therefore, the first liquid flows from the first supply channel 124a into the pressure chamber 22.

[0087] In this case, the second piezoelectric element 252b is driven to increase the volume of the curved portion 127 of the second supply channel 124b, and the third piezoelectric element 252c is driven to increase the volume of the curved portion 127 of the third supply channel 124c. Therefore, the valve body 251 of the second valve 250b is attracted to the communication opening 128 of the second supply channel 124b so that the communication opening 128 is covered therewith, and the valve body 251 of the third valve 250c is attracted to the communication opening 128 of the third supply channel 124c so that the communication opening 128 is covered therewith. Since the flow of liquid from the second supply channel 124b and the third supply channel 124c to the pressure chamber 22 is blocked, the first liquid is reliably supplied from the first supply channel 124a to the pressure chamber 22 in a state where the mixing of the liquids is prohibited.

[0088] Then, each of the piezoelectric elements 252a to 252c is driven to restore the original volume of the curved portion 127. Fig. 8A The liquid discharge from the nozzle 21 shown in FIG. Figure 8B The liquid supply to the pressure chamber 22 is shown in FIG.

[0089] <Fifth Modification>

[0090] In the head 20 according to the fifth modification, as Fig.9A and Fig. 9B As shown in FIG. 1 , the first supply channel 224a and the second supply channel 224b are stacked, and they are arranged at the side opposite to the third supply channel 224c, wherein the pressure chamber 22 is interposed between the channels 224a, 224b and the channel 224c. Except for this, the head 20 according to the fifth modification is the same or similar to the head 20 according to the first embodiment, and thus explanations of the same or similar features are omitted.

[0091] The channel forming body 30 further includes a second channel plate 35. The second channel plate 35 is disposed between the first channel plate 32 and the vibration plate 33 in the up-down direction. The pressure chamber 22 passes through the first channel plate 32 and the second channel plate 35 in the up-down direction. The lower end of the pressure chamber 22 is covered by the nozzle plate 31, and the upper end thereof is covered by the vibration plate 33.

[0092] The second supply channel 224b and the third supply channel 224c are formed by a recessed portion recessed from the lower surface of the first channel plate 32, and the upper end of each of the second supply channel 224b and the third supply channel 224c is covered by a portion included in the first channel plate 32 and located at the upper side of the recessed portion, and the lower end thereof is covered by the nozzle plate 31. The first supply channel 224a is formed by a recessed portion recessed from the lower surface of the second channel plate 35. The upper end of the first supply channel 224a is covered by a portion included in the second channel plate 35 and located at the upper side of the recessed portion, and the lower end of the first supply channel 224a is covered by the first channel plate 32.

[0093] The first supply channel 224a is arranged on the second supply channel 224b. The second supply channel 224b and the third supply channel 224c are arranged linearly, and the pressure chamber 22 is between them. For example, the three supply channels 224a to 224c extend in a direction intersecting (e.g., orthogonal) with their arrangement direction. In the pressure chamber 22, the first connection opening 23a and the second connection opening 23b are arranged in the up-down direction, and the second connection opening 23b faces the third connection opening 23c.

[0094] For example, there may be a case where the three supply channels 224a to 224c extend from the pressure chamber 22 in directions different from each other, and a case where the three supply channels 224a to 224c extend from the pressure chamber 22 in two directions. The dimensions in the directions orthogonal to the two directions in the latter case may be smaller. Therefore, the supply channels 224 can be arranged while inhibiting the size of the head 20 from increasing.

[0095] In the first valve 50a, the first piezoelectric element 52a is located at the upper side of the first valve body 51a. The first valve body 51a moves downward to cover the first connection opening 23a, and moves upward to open the first connection opening 23a. In the second valve 50b, the second piezoelectric element 52b is located at the lower side of the second valve body 51b. The second valve body 51b moves upward to cover the second connection opening 23b, and moves downward to open the second connection opening 23b. In the third valve 50c, the third piezoelectric element 52c is located at the lower side of the third valve body 51c. The third valve body 51c moves upward to cover the third connection opening 23c, and moves downward to open the third connection opening 23c.

[0096] <Other Modifications>

[0097] The head 20 according to the first embodiment and all the modifications has a first supply channel, a second supply channel, and a third supply channel. The number of supply channels is not limited thereto. For example, the head 20 may have only two supply channels (e.g., a first supply channel and a second supply channel) or four or more supply channels.

[0098] All of the above embodiments may be combined as long as no contradiction or exclusion is caused. For example, the second variation may be applied to the first variation, the third variation may be applied to the first and second variations, the fourth variation may be applied to the first to third variations, and the fifth variation may be applied to the first to fourth variations.

[0099] From the above description, many variations and other embodiments of the present disclosure are obvious to those skilled in the art. Therefore, the above description should be interpreted as examples only, and is provided to teach those skilled in the art the best mode for performing the present disclosure. Without departing from the gist of the present disclosure, the details of the above-mentioned configurations and / or functions may be substantially changed.

[0100] Industrial Applicability

[0101] The liquid discharge head of the present disclosure is useful, for example, as a liquid discharge head capable of reducing waste liquid while inhibiting an increase in the size of the apparatus.

Claims

1. A liquid discharge device, comprising: head; and A controller, wherein: The header includes: a pressure chamber connected to a nozzle from which liquid is discharged; an actuator configured to apply a discharge pressure to the liquid in the pressure chamber; a first supply channel connected to the pressure chamber and through which a first liquid is supplied to the pressure chamber; a second supply channel, the second supply channel being different from the first supply channel, the second supply channel being connected to the pressure chamber, and a second liquid different from the first liquid being supplied to the pressure chamber through the second supply channel; a first valve which is provided in the first supply passage and by which the first supply passage is opened and closed; a second valve that is provided in the second supply passage and by which the second supply passage is opened and closed; and the controller is configured to control the first valve to open the first supply channel and the second valve to close the second supply channel in a case where the first liquid is supplied to the pressure chamber and discharged from the nozzle, and to control the first valve to close the first supply channel and the second valve to open the second supply channel in a case where the second liquid is supplied to the pressure chamber and discharged from the nozzle; and The head is a stack of plates, and each of the pressure chamber, the first supply channel, the second supply channel, the first valve, and the second valve is located in the stack. 2 . The liquid discharge apparatus according to claim 1 , wherein each of the first valve and the second valve includes a valve body and a piezoelectric element configured to move the valve body. 3 . The liquid discharge apparatus according to claim 1 , wherein each of the first valve and the second valve includes a valve body and an electrostatic element configured to move the valve body.

4. The liquid discharge device according to claim 1, wherein: the head includes a channel forming body in which the first supply channel is formed, and the channel forming body has an inner surface that defines the first supply channel; and At least one of the first valve and the second valve has a valve body and an actuator configured to move the valve body. 5 . The liquid discharge apparatus according to claim 4 , wherein the valve body has a peripheral edge capable of abutting the inner surface, and the peripheral edge is formed of an elastic material. 6 . The liquid discharge apparatus according to claim 4 , wherein the valve body has a peripheral edge capable of abutting against the inner surface, and the peripheral edge is formed of a silicon coating film. 7 . The liquid discharge apparatus according to claim 4 , wherein the inner surface is formed to have a recess into which a peripheral edge of the valve body fits.

8. The liquid discharge apparatus according to claim 1, wherein the supply channel as at least one of the first supply channel and the second supply channel has a downstream portion and an upstream portion, the downstream portion being connected to the pressure chamber and the upstream portion communicating with the downstream portion, and The valve arranged at the supply passage as at least one of the first valve and the second valve is a check valve having a valve body provided in the downstream portion and configured to prohibit the liquid from flowing back from the downstream portion to the upstream portion.

9. A liquid discharge device according to any one of claims 1 to 6 and 8, wherein at least one of the first liquid and the second liquid is any one of water-based pigment ink, printing pigment ink, water-based sublimation ink, reactive dye ink, acid dye ink, disperse dye ink, solvent ink, UV ink, latex ink and cleaning liquid.

10. The liquid discharge device according to any one of claims 1 to 6 and 8, wherein: The header further comprises: a third supply channel that is different from the first supply channel and the second supply channel, is connected to the pressure chamber, and a third liquid that is different from the first liquid and the second liquid is supplied to the pressure chamber through the third supply channel; and a third valve which is provided in the third supply passage and by which the third supply passage is opened and closed.

11. The liquid discharge apparatus according to claim 10, wherein the pressure chamber has a cylindrical shape, and The first supply channel, the second supply channel, and the third supply channel are connected to the pressure chamber at regular intervals in a circumferential direction of the pressure chamber.

12. The liquid discharge apparatus according to claim 10, wherein the first supply channel and the second supply channel are stacked on each other, and The first supply channel and the second supply channel are arranged at a side opposite to the third supply channel side, with the pressure chamber interposed between the first supply channel and the second supply channel and the third supply channel.

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