Liquid ejection head and liquid ejection device

Abstract

To provide a liquid ejection head that is electrically safe.SOLUTION: A liquid ejection head capable of ejecting a liquid includes: a storage unit capable of storing the liquid; an element substrate including a plurality of ejections ports that eject the liquid supplied from the storage unit; a drive unit that is driven by its being supplied with power at a predetermined voltage; a housing supporting the element substrate, the storage unit, and the drive unit; an electric circuit board on which high-voltage wiring, to which predetermined voltage is applied, is disposed; and a flame-retardant portion having a flame-retardancy grade of V-1 or higher. The electric circuit board includes a core member having a flame retardancy grade of V-1 or higher. The flame retardant portion is disposed closer to the housing than the electric circuit board. The high-voltage wiring is disposed between the core member and the flame retardant portion.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present disclosure relates to a liquid ejection head and a liquid ejection apparatus. [Background technology]

[0002] Patent Document 1 shows a drive waveform generated by a circuit for driving a pump provided in an inkjet head (liquid ejection head). By referring to this drive waveform, it can be understood that a voltage of 120 V to 300 V is applied to the circuit. In this way, in a liquid ejection head configured to receive power at a relatively high voltage, unexpected events can occur due to components to which a relatively high voltage is applied. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2018-30350 Summary of the Invention [Problem to be solved by the invention]

[0004] However, Patent Document 1 does not mention anything about the electrical safety of the liquid ejection head.

[0005] Therefore, an object of the present disclosure is to provide a liquid ejection head that can ensure electrical safety. [Means for solving the problem]

[0006] The liquid ejection head of the present disclosure is a liquid ejection head capable of ejecting liquid, and comprises: a storage section capable of storing liquid; an element substrate including a plurality of ejection ports for ejecting liquid supplied from the storage section; a drive section that is driven by a supply of power at a predetermined voltage; a housing that supports the element substrate, the storage section, and the drive section; an electric circuit board on which high-voltage wiring to which the predetermined voltage is applied is arranged; and a flame-retardant section having a flame-retardant grade of V-1 or higher, wherein the electric circuit board includes a core member having a flame-retardant grade of V-1 or higher, the flame-retardant section is positioned closer to the housing than the electric circuit board, and the high-voltage wiring is positioned between the core member and the flame-retardant section. [Effects of the Invention]

[0007] According to the liquid ejection head of the present disclosure, electrical safety can be ensured. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is an external perspective view showing an example of a liquid ejection apparatus that can be used in an embodiment. [Figure 2] FIG. 2 is a block diagram showing a control system of the liquid ejection device according to an embodiment. [Figure 3] FIG. 1 is an exploded perspective view of a liquid ejection head according to an embodiment. [Figure 4] FIG. 1 is a schematic diagram of a circulation unit that can be applied to one embodiment. [Figure 5] FIG. 10 is a schematic diagram showing a circulation path that can be applied to one embodiment. [Figure 6] FIG. 1 is a schematic diagram of a drive circuit for a circulation pump that can be applied to one embodiment. [Figure 7] FIG. 1 is a schematic cross-sectional view of an electric circuit board according to an embodiment. [Figure 8] FIG. 2 is an exploded perspective view showing an electric circuit board and components arranged around the electric circuit board. [Figure 9] FIG. 1 is a schematic cross-sectional view of an electric circuit board that can be applied to an embodiment. [Figure 10]FIG. 1 is a schematic cross-sectional view of a liquid ejection head that can be applied to an embodiment. [Figure 11] FIG. 3 is an enlarged cross-sectional view of the vicinity of a discharge port in one embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] [First embodiment] Hereinafter, examples of embodiments of the present disclosure will be described with reference to the drawings. However, the following description does not limit the scope of the present disclosure.

[0010] <Description of the liquid ejection device> FIG. 1 is a perspective view showing an example of a liquid ejection device 100 that can be used in this embodiment.

[0011] The coordinate axes in the drawings will now be described. In the drawings referred to in this specification, the X and Y directions refer to two directions that are perpendicular to each other on a horizontal plane. The Z direction refers to the vertical direction. The +Y direction refers to the front of the liquid ejection device 100, the -Y direction refers to the rear, the -X direction refers to the left, the +X direction refers to the right, the +Z direction refers to the top, and the -Z direction refers to the bottom. The +Y direction is also downstream in the transport direction of the paper 101, and the -Y direction is upstream in the transport direction of the recording medium. The X direction will be referred to as the scanning direction where appropriate. In the following description, unless otherwise specified, top, bottom, left, and right refer to the directions in which the liquid ejection device 100 is used in its normal operating position.

[0012] In this embodiment, the description will be made assuming that the "liquid" is ink. However, the liquid that can be used in this embodiment is not limited to ink. In other words, various recording liquids may be used, including treatment liquids that are used for the purposes of improving the fixation of ink on a recording medium, reducing uneven gloss, or improving abrasion resistance.

[0013] In this embodiment, the description will be made assuming that the "recording medium" is paper 101 used in general liquid ejection devices. However, the "recording medium" is not limited as long as it is a medium that can accept liquid. Other examples of the "recording medium" include cloth, plastic film, metal plate, glass, ceramics, resin, wood, leather, etc.

[0014] "Recording" (also called "printing") does not only mean forming meaningful information such as letters and figures. "Recording" also means forming meaningless information such as images, designs, or patterns. Furthermore, "recording" does not matter whether it is something that is visible to humans or not. In other words, "recording" also means forming a structure on paper 101 or processing a medium.

[0015] As shown in Fig. 1, in this embodiment, the liquid ejection device 100 will be described assuming that it is an inkjet printer that ejects ink in a so-called serial manner. The liquid ejection device 100 includes a liquid ejection head 102 that can eject ink onto paper 101. The liquid ejection head 102 is detachable from a carriage 103 that can move back and forth in the scanning direction (±X direction). The carriage 103 is supported by a guide shaft 104 that extends in the scanning direction so as to be slidable along the guide shaft 104. The carriage 103 is fixed to an endless belt 105 that is arranged parallel to the guide shaft 104.

[0016] With the carriage 103 fixed to the endless belt 105, the ejection port surface of the liquid ejection head 102, in which ejection ports (not shown in FIG. 1) for ejecting ink are formed, is maintained in a state facing parallel to a platen (not shown) that supports the paper 101 from the -Z direction side. A drive pulley (not shown) is rotated by driving a carriage motor 205 (see FIG. 2). The forward and reverse rotation of the drive pulley causes the endless belt 105 to move leftward (-X direction) and rightward (+X direction). In this way, as the endless belt 105 moves along the scanning direction, the carriage 103 also moves back and forth along the guide shaft 104 in the scanning direction.

[0017] A number of circulation units 106 corresponding to the number of types of liquid that the liquid ejection head 102 can eject are attached to the liquid ejection head 102. In this embodiment, the liquid ejection head 102 is capable of ejecting four colors of ink: cyan, magenta, yellow, and black. Therefore, four circulation units 106 corresponding to each of these four colors are attached to the liquid ejection head 102. The liquid ejection head 102 configured in this manner is capable of full-color printing using these four colors of ink. Note that the colors of ink that can be applied to this embodiment are not limited to the four colors described above.

[0018] The liquid ejection device 100 includes an ink tank 107 disposed at a position away from the liquid ejection head 102, and an external pump 108 for supplying ink from the ink tank 107 to a circulation unit 106. Tubes for supplying ink from the ink tank 107 via the external pump 108, piping for supplying air, and the like are connected to the liquid ejection head 102. These tubes and piping are guided to the liquid ejection head 102 along guides 110.

[0019] A first substrate 109 on which electrical wiring for various purposes is arranged is disposed inside the liquid ejection device 100. Wiring for sending electrical signals to drive the liquid ejection head 102 is connected to the carriage 103. The wiring is also guided to the liquid ejection head 102 along a guide 110.

[0020] The liquid ejection device 100 includes a transport unit for transporting the paper 101 in a transport direction. In this embodiment, the transport direction is set to a direction (+Y direction) perpendicular to the scanning direction. The transport unit is driven by a transport motor 207 (see FIG. 2). The transport unit includes a first transport roller 111, a second transport roller 112, a third transport roller 113, and a fourth transport roller 114. The transport motors that drive these transport rollers are rotatable in both forward and reverse directions.

[0021] On the upstream side (-Y direction side) of the carriage 103 in the conveying direction, the first conveying roller 111 and the second conveying roller 112 can hold the paper 101. On the downstream side (+Y direction side) of the carriage 103 in the conveying direction, the third conveying roller 113 and the fourth conveying roller 114 can hold the paper 101 on the downstream side (+Y direction side) of the carriage 103.

[0022] The first transport roller 111 and the second transport roller 112 rotate in opposite directions while holding the paper 101. The third transport roller 113 and the fourth transport roller 114 rotate in opposite directions while holding the paper 101. By rotating the transport unit in this manner, the paper 101 is transported in the transport direction (+Y direction).

[0023] The liquid ejection device 100 performs recording by intermittently moving the paper 101 downstream in the transport direction (toward the +Y direction) while moving the liquid ejection head 102 in the scanning direction and ejecting ink. Hereinafter, such an operation of the liquid ejection head 102 will be referred to as a recording operation.

[0024] The liquid ejection device 100 includes a recovery unit (not shown) for maintaining and recovering the ejection performance of the ejection ports. The recovery unit is located within an area in which the liquid ejection head 102 can move, but at a position away from the transport path of the paper 101. When no recording operation is being performed, a cap included in the recovery unit moves relatively to a position that covers the ejection port surface of the liquid ejection head 102 on which the ejection ports are formed. Covering the ejection port surface with the cap can prevent the ejection ports from drying out. Ink is filled while the ejection port surface is covered with the cap. Furthermore, ink remaining near the ejection ports is absorbed while the ejection port surface is covered with the cap, preventing ink clogging and thickening of the ink.

[0025] <Control System of Liquid Discharge Apparatus 100> FIG. 2 is a block diagram showing a control system of the liquid ejection device 100 according to this embodiment.

[0026] As shown in FIG. 2, a host device 200 capable of issuing commands to the liquid ejection device 100 to execute a recording operation is disposed outside the liquid ejection device 100.

[0027] The liquid ejection device 100 includes a CPU 201 for controlling the entire device, a ROM 202 in which programs executed by the CPU 201 and various parameters are stored, and a RAM 203 that can be used as a storage unit.

[0028] The liquid ejection device 100 includes a head driver 204 for driving the liquid ejection head 102. The liquid ejection device 100 includes a carriage motor 205 for driving the carriage 103 (see FIG. 1), and a carriage motor driver 206 for controlling the carriage motor 205. The liquid ejection device 100 includes a transport motor 207 for driving the transport unit, and a transport motor driver 208 for controlling the transport motor 207.

[0029] A printer driver is installed in the host device 200 to collect recording information such as the recorded image and the quality of the recorded image when a user commands the execution of a recording operation, and to communicate with the liquid ejection device 100. The CPU 201 is configured to be able to send and receive various data (for example, the recorded image) to and from the host device 200.

[0030] The CPU 201 functions as a control unit that controls the operation of each unit, data processing, and the entire liquid ejection device 100, including the liquid ejection head 102. The ROM 202 is configured to be able to store programs and various data executed by the CPU 201. The RAM 203 temporarily stores processing data executed by the CPU 201 and data received from the host device 200.

[0031] <Description of Liquid Ejection Head 102> FIG. 3 is an exploded perspective view of the liquid ejection head 102 of this embodiment.

[0032] 3, the liquid ejection head 102 includes an ejection unit 300 for ejecting ink, a housing 301 capable of accommodating the circulation unit 106, the circulation unit 106, and an electric circuit board 302 fixed to the housing 301. The ejection unit 300 includes a face cover 303 capable of covering part of the bottom surface of the liquid ejection head 102, and an element substrate 304 equipped with predetermined elements.

[0033] The element substrate 304 includes a first element substrate 304a and a second element substrate 304b. The first element substrate 304a is capable of ejecting first and second types of liquid. The second element substrate 304b is capable of ejecting third and fourth types of liquid. When there is no need to particularly distinguish between the first element substrate 304a and the second element substrate 304b, they are referred to as element substrates 304.

[0034] The ejection unit 300 includes a connection board 305 that can electrically connect the electric circuit board 302 and the element board 304 , and a support member 306 that supports the element board 304 .

[0035] In this embodiment, a flow path is formed on the rear surface (the surface facing the -Y direction in this embodiment) and bottom of the housing 301 to supply ink supplied from the ink tank 107 (see FIG. 1) to the ejection unit 300. A connection part 307 is formed on the rear surface of the housing 301 as a flow path to supply ink supplied from the ink tank 107 (see FIG. 1) to the circulation unit 106. An end of a tube guided from the ink tank 107 (see FIG. 1) along the guide 110 (see FIG. 1) is connected to the connection part 307.

[0036] In this embodiment, the connection portion 307 includes a first connection portion 307m, a second connection portion 307y, a third connection portion 307k, and a fourth connection portion 307c. A tube that supplies magenta ink is connected to the first connection portion 307m. A tube that supplies yellow ink is connected to the second connection portion 307y. A tube that supplies black ink is connected to the third connection portion 307k. A tube that supplies cyan ink is connected to the fourth connection portion 307c. Hereinafter, when there is no need to particularly distinguish between the first connection portion 307m, the second connection portion 307y, the third connection portion 307k, and the fourth connection portion 307c, they will be referred to as connection portion 307.

[0037] The circulation unit 106 includes a first circulation unit 106m, a second circulation unit 106y, a third circulation unit 106k, and a fourth circulation unit 106c, which correspond to the four colors of ink: magenta, yellow, black, and cyan. Hereinafter, when there is no need to distinguish between the first circulation unit 106m, the second circulation unit 106y, the third circulation unit 106k, and the fourth circulation unit 106c, they will be referred to as circulation units 106.

[0038] The first connector 307m is connected to the first circulation unit 106m. The second connector 307y is connected to the second circulation unit 106y. The third connector 307k is connected to the third circulation unit 106k. The fourth connector 307c is connected to the fourth circulation unit 106c.

[0039] A flow path is formed in the bottom of the housing 301 to supply the ink supplied from the circulation unit 106 to the ejection unit 300. In this way, the ink supplied to the connection part 307 is supplied to the ejection unit 300 via the circulation unit 106 and the flow path formed in the bottom of the housing 301.

[0040] The top surface of the support member 306 is joined to the bottom surface of the housing 301. The support member 306 has a plurality of through holes formed therein that pass through the support member 306 in the vertical direction (Z direction). The support member 306 has a through hole that can supply magenta ink and a through hole that can supply yellow ink from the housing 301 to the first element substrate 304a. The support member 306 has a through hole that can supply black ink and a through hole that can supply cyan ink from the housing 301 to the second element substrate 304b.

[0041] The upper surface of the element substrate 304 is joined to the bottom surface of the support member 306. The element substrate 304 has a plurality of openings formed therein that can be connected to the plurality of through holes formed in the support member 306. With this configuration, ink supplied to the circulation unit 106 is supplied to the element substrate 304 via the flow path formed in the bottom of the housing 301 and the through holes formed in the support member 306.

[0042] Furthermore, an electric circuit board 302 is fixed to the front surface (the surface facing the +Y direction in this embodiment) of the housing 301. The electric circuit board 302 has a surface (the surface facing the -Y direction) that is fixed to the housing 301, and a contact surface (the surface facing the +Y direction) that faces the opposite direction. With this configuration, an electric signal transmitted from the device main body to the contact surface of the electric circuit board 302 is transmitted to the element substrate 304 via the connection substrate 305.

[0043] The ejection port surface of the element substrate 304 is formed with an ejection port array, in which a plurality of ejection ports capable of ejecting ink supplied from the circulation unit 106 are arranged along the Y direction. Energy generating elements (e.g., heaters) that impart energy to the ink to eject the ink are arranged at positions corresponding to the plurality of ejection ports. These energy generating elements are driven by the head driver 204 (see FIG. 2) in response to an electrical signal input to the connection substrate 305. In this manner, the energy generating elements are driven in response to the electrical signal, causing ink to be ejected from the element substrate 304. The element substrate 304 is not covered by the face cover 303.

[0044] In this embodiment, when magenta ink is supplied to the first element substrate 304a, magenta ink is ejected from the first ejection port array, and when yellow ink is supplied, yellow ink is ejected from the second ejection port array. When black ink is supplied to the second element substrate 304b, black ink is ejected from the third ejection port array, and when cyan ink is supplied, cyan ink is ejected from the fourth ejection port array. The upper surface (surface facing the +Z direction) of the face cover 303 is joined to the lower surface (surface facing the -Z direction) of the connection substrate 305.

[0045] The face cover 303 can protect the ejection port surface of the element substrate 304 from rubbing by the wiper during wiping and from rubbing by the paper during printing.

[0046] <Explanation of the circulation route> FIG. 4 is a schematic diagram of a circulation unit 106 that can be applied to this embodiment. As described above, the circulation unit 106 includes a first circulation unit 106m, a second circulation unit 106y, a third circulation unit 106k, and a fourth circulation unit 106c. For ease of explanation, FIG. 4 uses one of the first circulation unit 106m, the second circulation unit 106y, the third circulation unit 106k, and the fourth circulation unit 106c as an example. The first circulation unit 106m, the second circulation unit 106y, the third circulation unit 106k, and the fourth circulation unit 106c are all identical in configuration except for the color of the circulating ink.

[0047] As shown in FIG. 4, the circulation unit 106 includes a filter 401 capable of removing dust and other particles from the ink, and a drive unit that is driven by power supplied via an electric circuit board 302 (see FIG. 3).

[0048] In this embodiment, the driving unit is a circulation pump 402. The circulation pump 402 is a piezoelectric diaphragm pump that can change the volume inside the pump chamber by inputting a driving voltage to a piezoelectric element attached to a diaphragm, and can pump liquid by alternately moving two check valves due to pressure fluctuations.

[0049] The circulation unit 106 includes a first pressure control mechanism 403 as a first pressure control means, and a second pressure control mechanism 404 as a second pressure control means. The first pressure control mechanism 403 and the second pressure control mechanism 404 also function as a storage section capable of temporarily storing a liquid therein.

[0050] FIG. 5 is a schematic diagram showing circulation paths that can be applied to this embodiment. In this embodiment, there are four circulation paths. For ease of explanation, FIG. 5 will explain one of the four circulation paths as an example. The configuration of these four circulation paths is all the same except for the color of the circulating ink.

[0051] 5, the first pressure control mechanism 403 includes a first valve chamber 501 and a first pressure control chamber 502, which are connected to each other via a first valve (not shown). The second pressure control mechanism 404 includes a second valve chamber 503 and a second pressure control chamber 504, which are connected to each other via a second valve (not shown).

[0052] The first pressure control chamber 502 and the discharge unit 300 are connected via a supply flow path 505 formed in the bottom of the housing 301 (see FIG. 2). The discharge unit 300 and the second pressure control chamber 504 are connected via a recovery flow path 506 formed in the bottom of the housing 301 (see FIG. 2). The second pressure control chamber 504 and the circulation pump 402 are connected via a pump inlet flow path 507 formed on the upstream side of the circulation pump 402. The circulation pump 402 and the first pressure control chamber 502 are connected via a pump outlet flow path 508 formed on the downstream side of the circulation pump 402. The first pressure control chamber 502 and the second valve chamber 503 are connected via a bypass flow path 509.

[0053] In this way, a circulation path that can circulate ink is formed inside the liquid ejection head 102. In this embodiment, the circulation path refers to the path that runs from the first pressure control mechanism 403, through the ejection unit 300, the second pressure control mechanism 404, and the circulation pump 402, and then back to the first pressure control mechanism 403.

[0054] <Ink circulation> When ink is circulated, ink is pressurized and supplied from the ink tank 107 to the first valve chamber 501 via the filter 401 by driving the external pump 108. The filter 401 removes dust and other particles from the ink.

[0055] Thereafter, the pressure is adjusted so that ink is supplied from first valve chamber 501 to first pressure control chamber 502. Specifically, when ink is supplied to first valve chamber 501, circulation pump 402 is driven so that ink is supplied from pump inlet channel 507 to pump outlet channel 508. By driving circulation pump 402, the pressure inside first pressure control chamber 502 is controlled.

[0056] By controlling the pressure inside the first pressure control chamber 502, ink is supplied from the first pressure control chamber 502 to the ejection unit 300 via the supply flow path 505, and is also supplied to the second valve chamber 503 via the bypass flow path 509.

[0057] The ink supplied to the ejection unit 300 is supplied to the second pressure control mechanism 404 via a flow path formed in the support member 306, a flow path formed inside the element substrate 304 (see FIG. 3), and a recovery flow path 506. Specifically, in the element substrate 304, the ink passes through a pressure chamber formed inside the element substrate 304. An ejection port is formed so as to be continuous with this pressure chamber. An energy generating element is arranged at a position corresponding to the ejection port.

[0058] The ink supplied from the first pressure control chamber 502 to the second valve chamber 503 is supplied to the second pressure control chamber 504 which is connected to the second valve chamber 503 via a second valve.

[0059] The ink supplied to the second pressure control chamber 504 is supplied to the first pressure control chamber 502 via the pump inlet flow path 507 , the circulation pump 402 , and the pump outlet flow path 508 .

[0060] In this way, in this embodiment, by driving the circulation pump 402, it is possible to circulate ink between the first valve chamber 501 and the ejection unit 300. By circulating ink in this way, it is possible to prevent the ink from becoming thicker inside the element substrate 304 (see FIG. 3). Note that, as long as the ink viscosity can be prevented from increasing, the circulation path does not have to include the pressure chamber of the element substrate 304. It is sufficient that the circulation path is formed so as to circulate ink inside the ejection unit 300 to an extent that the ink viscosity near the energy generating elements can be prevented from increasing.

[0061] <Configuration for Driving Circulation Pump 402> FIG. 6 is a schematic diagram showing a configuration for driving the circulation pump 402 that can be applied to this embodiment.

[0062] As shown in Fig. 6, the CPU 201 is mounted on a first board 109. The carriage 103 includes a second board 601 on which electrical wiring for various uses is arranged. The CPU 201 and the second board 601 are connected via a first wiring 600. An example of the first wiring 600 is an FFC (Flexible Flat Cable). The second board 601 and the electric circuit board 302 are electrically connected via an electrical connection portion 602 formed by contact connection.

[0063] Terminals 800 (see FIG. 8) to which electrical connection parts 602 can be connected are arranged on the contact surface of electric circuit board 302. Electric circuit board 302 and circulation pump 402 are electrically connected via third wiring 603. Third wiring 603 is configured to enable power to be supplied from electric circuit board 302 to circulation pump 402.

[0064] When circulating ink, an electrical signal (drive signal) for driving the circulation pump 402 is transmitted from the CPU 201 to the second substrate 601 via the first wiring 600. The drive signal transmitted to the second substrate 601 is then transmitted to the electric circuit board 302 via the electrical connection portion 602. The circulation pump 402 is disposed inside the housing 301. In this way, the circulation pump 402 is disposed closer to the housing 301 than the electric circuit board 302.

[0065] <Flame retardant measures> Generally, when a circulation pump is disposed in a liquid ejection head, it is difficult to increase the size of the circulation pump due to size restrictions on the liquid ejection head, and therefore the voltage of the power supplied to the circulation pump tends to be high in order to ensure the necessary circulation flow rate.

[0066] In this embodiment, the circulation pump 402 is driven by a high-voltage current being supplied, and therefore, in order to stabilize the electrical connection, flame retardancy measures are taken for the liquid ejection head 102 of this embodiment.

[0067] FIG. 7 is a schematic cross-sectional view of an electric circuit board 302 in this embodiment.

[0068] As shown in FIG. 7, the electric circuit board 302 is constructed by sandwiching a flame-retardant plate-shaped core member 703 between a first prepreg 701 made of glass epoxy and a second prepreg 702 made of glass epoxy.

[0069] In this embodiment, "having flame retardancy" means that the flame retardancy grade according to the UL94 standard is V-1 or higher. For example, the core member 703 is made up of silicon, which has a flame retardancy grade of V-0 according to the UL94 standard, which is better than V-1. Therefore, it can be said that the core member 703 has flame retardancy. Note that the material making up the core member 703 is not limited to silicon, as long as the flame retardancy grade according to the UL94 standard is V-1 or higher.

[0070] With the electric circuit board 302 attached to the housing 301 (see FIG. 3), the first prepreg 701 is disposed on the main body side of the liquid ejection device 100 (see FIG. 1) with the core member 703 as the boundary. On the other hand, with the electric circuit board 302 attached to the housing 301 (see FIG. 3), the second prepreg 702 is disposed on the housing 301 side (head side) with the core member 703 as the boundary.

[0071] The core member 703 has via holes 704 formed therein that allow electrical signals to be transmitted from the main body side to the head side across the core member 703. When the electric circuit board 302 is attached to the housing 301 (see FIG. 3), the via holes 704 are formed so as to penetrate the core member 703 in the Y direction.

[0072] In the electric circuit board 302, on the side of the core member 703 that faces the housing 301 (see FIG. 3), a boost circuit 705 that can boost an input first voltage to a second voltage, and a fourth wiring 706 to which the second voltage is applied are arranged. In this embodiment, the fourth wiring 706 is routed two-dimensionally. In the electric circuit board 302, on the side of the core member 703 that faces the housing 301 (see FIG. 3), a connector 707 that connects the fourth wiring 706 and the third wiring 603 is also arranged. In this way, the boost circuit 705, the fourth wiring 706, and the connector 707 are arranged only on the side of the core member 703 that faces the housing 301 (see FIG. 3).

[0073] In this embodiment, the via hole 704 is formed so that a drive signal for driving the circulation pump 402 can be input to the boost circuit 705. When circulating ink, the drive signal is transmitted from the CPU 201 (see FIG. 6) to the boost circuit 705 via the via hole 704. The drive signal input to the boost circuit 705 is transmitted to the connector 707 via the fourth wiring 706. The drive signal input to the connector 707 is transmitted to the circulation pump 402 via the third wiring 603. As described above, the circulation pump 402 is driven by being supplied with relatively high-voltage power.

[0074] In this embodiment, high voltage means 42.4 V (volts) or higher. Specifically, the circulation pump 402 is driven by being supplied with power at a voltage of 66 V or higher. Therefore, the boost circuit 705 is configured to boost the voltage of the input drive signal from 5 V to 66 V and supply it to the fourth wiring 706. In other words, the fourth wiring 706 is a high-voltage wiring to which a voltage of 42.4 V or higher is applied.

[0075] The electric circuit board 302 includes a control chip (not shown) for controlling the operation of the circulation pump 402, and a voltage dividing circuit (not shown) capable of dividing an applied voltage to a predetermined voltage. In the electric circuit board 302, when the control chip receives a drive signal for driving the circulation pump 402, it outputs a boost signal to the boost circuit 705 for boosting the voltage from 5 V to 66 V. The power boosted to 66 V by the boost circuit 705 is supplied to the circulation pump 402 via the fourth wiring 706, the connector 707, and the third wiring 603.

[0076] Therefore, in this embodiment, it is necessary to ensure the electrical safety of the head side of the electric circuit board 302 to which high voltage power is supplied.

[0077] FIG. 8 is an exploded perspective view showing the electric circuit board 302 and the members arranged around it.

[0078] 8, electric circuit board 302 is fixed to housing 301. When electric circuit board 302 is fixed to housing 301, terminals 800 to which electric connection part 602 (see FIG. 6) can be connected are arranged on a contact surface of electric circuit board 302 facing in the opposite direction from the opposing surface facing housing 301. By connecting electric connection part 602 (see FIG. 6) to terminals 800, it is possible to receive a drive signal transmitted from CPU 201 (see FIG. 2).

[0079] The housing 301 includes a connection member 801 in which a connection portion 307 is formed, a support housing 802 for supporting the connection member 801, and a cover 803 for covering the top of the circulation unit 106 (see FIG. 1).

[0080] The connecting member 801, the supporting housing 802, and the cover 803 are made of a resin having a flame retardancy grade of V-1 or higher according to the UL94 standard. Materials that make up the connecting member 801, the supporting housing 802, and the cover 803 include, for example, PPO (polyphenylene oxide), PS (polystyrene), PPE (polyphenylene ether), and PPS (polyphenylene sulfide).

[0081] The connecting member 801, the supporting housing 802, and the cover 803 are made of, for example, a composite material made of PPO and PS. The connecting member 801, the supporting housing 802, and the cover 803 may be made of a composite material made of PPE and PS. The connecting member 801, the supporting housing 802, and the cover 803 may be made of a composite material made of PPE and PPS.

[0082] Support housing 802 has a recess formed therein that can cover boost circuit 705 (see FIG. 7), fourth wiring 706 (see FIG. 7), and connector 707 (see FIG. 7) of electric circuit board 302. According to this configuration, when electric circuit board 302 is attached to support housing 802, a space is formed that is made up of core member 703 (see FIG. 7) and support housing 802. Then, when electric circuit board 302 is attached to support housing 802, boost circuit 705 (see FIG. 7), fourth wiring 706 (see FIG. 7), and connector 707 (see FIG. 7) are shielded inside this space. In other words, when electric circuit board 302 is attached to support housing 802, components to which a high voltage is applied are shielded by flame-retardant core member 703 (see FIG. 7) and support housing 802. Therefore, even when high voltage power is supplied to the electric circuit board 302, flame retardancy is ensured on the head side across the core member 703.

[0083] Therefore, the liquid ejection head of this embodiment can ensure electrical safety.

[0084] Furthermore, by arranging the boost circuit 705, the fourth wiring 706, and the connector 707 inside the space shielded by the flame-retardant member, electrical safety on the main body side, with the core member 703 as the boundary, can be improved. In this case, the size of the via hole 704 is preferably smaller than φ0.8. With this configuration, even if an unexpected event occurs due to the fourth wiring 706, the event can be further prevented from passing through the via hole 704 and spreading from the head side to the main body side.

[0085] Additionally, in electric circuit board 302, the components to which high-voltage power is supplied are located only on the head side, separated by core member 703. Therefore, the area requiring flame retardant measures is limited to the head side, separated by core member 703. Therefore, compared to applying flame retardant measures to the entire electric circuit board 302, the cost required for flame retardant measures can be reduced.

[0086] [Second embodiment] A second embodiment of the technology of the present disclosure will be described below with reference to the drawings. The difference between the liquid ejection head of the first embodiment and the liquid ejection head of this embodiment is the arrangement of high-voltage wiring. In the following description, the same reference numerals will be used to designate components similar to or corresponding to those of the first embodiment, and a description will be omitted, with the differences being mainly described.

[0087] FIG. 9 is a schematic cross-sectional view of a second electric circuit board 900 that can be applied to this embodiment.

[0088] 9, second electric circuit board 900 includes fifth wiring 901 that is connected to boost circuit 705 and receives 66V of power. Fifth wiring 901 is routed three-dimensionally only on the housing 301 (see FIG. 3) side (head side) with core member 703 as the boundary. With such an arrangement, there is a portion of the wiring routed inside second electric circuit board 900, and therefore flame retardancy is improved compared to fourth wiring 706 (see FIG. 7) that is routed two-dimensionally.

[0089] Therefore, according to the liquid ejection head of this embodiment, the risk of unexpected events occurring due to the fifth wiring 901 can be reduced more than in the first embodiment.

[0090] [Third embodiment] A third embodiment of the technology of the present disclosure will be described below with reference to the drawings. The liquid ejection head of this embodiment has additional flame retardant measures implemented compared to the first and second embodiments. In the following description, the same reference numerals will be used to designate components similar to or corresponding to those of the first and second embodiments, and a description will be omitted. The following description will focus on the differences.

[0091] FIG. 10 is a schematic cross-sectional view of a second liquid ejection head 1000 that can be applied to this embodiment.

[0092] 10, the second liquid ejection head 1000 includes a sixth wiring 1001 that electrically connects the electric circuit board 302 and the element board 304. An example of the sixth wiring 1001 is an FPC (Flexible Printed Circuit).

[0093] The second liquid ejection head 1000 includes a flame-retardant member 1002 capable of covering the outside of the electric circuit board 302. A sealing member 1003 capable of sealing any gaps that occur between the sixth wiring 1001 and the flame-retardant member 1002 is disposed between the sixth wiring 1001 and the flame-retardant member 1002. The gaps that occur between the element substrate 304 and the flame-retardant member 1002 are also sealed by the sealing member 1003. The flame-retardant member 1002 and the sealing member 1003 are made of a material with a flame-retardant grade of V-1 or higher according to the UL94 standard.

[0094] As will be described in more detail later, in this embodiment, a voltage of 42.4 V or more is applied to the sixth wire 1001. The sixth wire 1001 is arranged closer to the flame-retardant housing 301 than the electric circuit board 302. The outside of the sixth wire 1001 is covered with a sealing member 1003, the electric circuit board 302, and the flame-retardant member 1002.

[0095] FIG. 11 is an enlarged cross-sectional view of the vicinity of the discharge port in this embodiment.

[0096] 11, the element substrate 304 includes an ejection port forming member 1101 in which a plurality of ejection ports 1100 are formed, and energy generating elements 1102 that are arranged at positions corresponding to the ejection ports 1100 and generate energy used to eject ink. The element substrate 304 also includes a flow path member 1103 in which a flow path capable of supplying ink to the ejection port forming member 1101 is formed.

[0097] Meanwhile, a flame-retardant plate 1104 having a flame-retardant grade of V-1 or higher according to the UL94 standard is bonded to the underside of the ejection port forming member 1101. The flame-retardant plate 1104 has through holes 1105 formed therein so as not to impede the outflow of ink ejected from the ejection ports 1100. The flame-retardant plate 1104 and the sixth wiring 1001 are bonded together via a sealing member 1003.

[0098] In this embodiment, a heater that generates heat when a predetermined voltage is applied can be used as the energy generating element 1102. The heater in this embodiment is disposed closer to the housing 301 than the electric circuit board 302 (see FIG. 10). The heater in this embodiment is driven by receiving an electric signal (ejection signal) for ejecting ink. Specifically, the heater in this embodiment is driven by being supplied with power of 60.0 V DC or 42.4 V AC. Therefore, a voltage of at least 42.4 V is applied to the sixth wiring 1001 electrically connected to the energy generating element 1102. Therefore, in this embodiment, a flame retardant measure is implemented for the sixth wiring 1001.

[0099] 10, the sixth wiring 1001 is disposed closer to the housing 301 than the electric circuit board 302. The outside of the sixth wiring 1001 is covered with a flame-retardant plate 1104 (see FIG. 11), a sealing member 1003, and a flame-retardant member 1002, as shown in FIG. 11. In this way, the sixth wiring 1001 is shielded by a flame-retardant member, thereby improving the flame retardancy of the second liquid ejection head 1000.

[0100] Therefore, the second liquid ejection head 1000 can provide higher electrical safety than the first embodiment. The ejection port forming member 1101 may be made of a material with a flame retardancy grade of V-1 or higher according to the UL94 standard. In this case, electrical safety can be further improved.

[0101] [Other embodiments] The fourth wiring 706 (see FIG. 7) may be shielded by a film made of a material having a flame-retardant grade of V-1 or higher according to the UL94 standard. In this case, the housing 301 does not need to be flame-retardant. Even with this configuration, the fourth wiring 706 is shielded by the flame-retardant core member 703 and the flame-retardant film, thereby improving electrical safety.

[0102] The fifth wiring 901 (see FIG. 9) may be shielded by a film made of a material having a flame-retardant grade of V-1 or higher according to the UL94 standard. In this case, the housing 301 does not need to be flame-retardant. Even with this configuration, the fifth wiring 901 is shielded by the flame-retardant core member 703 and the flame-retardant film, thereby improving electrical safety.

[0103] The first, second, and third embodiments employ a so-called thermal method in which a heater generates bubbles to eject liquid, but the technology of the present disclosure can also be applied to liquid ejection heads employing a piezo method and various other liquid ejection methods.

[0104] The present disclosure includes the following configurations.

[0105] [Configuration 1] A liquid ejection head capable of ejecting liquid, a storage section capable of storing a liquid; an element substrate including a plurality of ejection ports for ejecting the liquid supplied from the container; a drive unit that is driven by being supplied with power at a predetermined voltage; a housing that supports the element substrate, the housing portion, and the drive portion; an electric circuit board on which high-voltage wiring to which the predetermined voltage is applied is arranged; a flame-retardant part having a flame-retardant grade of V-1 or higher; Equipped with The electric circuit board includes a core member having a flame retardancy grade of V-1 or higher, the flame-retardant portion is disposed closer to the housing than the electric circuit board, The high-voltage wiring is disposed between the core member and the flame-retardant portion. A liquid ejection head characterized by:

[0106] [Configuration 2] the flame-retardant portion is a film, The high-voltage wiring is shielded by the film. The liquid ejection head according to configuration 1.

[0107] [Configuration 3] the flame-retardant portion is a part of the housing, the high-voltage wiring is shielded by the electric circuit board and a part of the housing; 3. The liquid ejection head according to claim 1 or 2.

[0108] [Configuration 4] In the electric circuit board, the high-voltage wiring is routed two-dimensionally closer to the housing than the core member. 4. The liquid ejection head according to any one of the first to third aspects.

[0109] [Configuration 5] In the electric circuit board, the high-voltage wiring is three-dimensionally routed closer to the housing than the core member. 5. The liquid ejection head according to any one of the first to fourth aspects.

[0110] [Configuration 6] a boost circuit for boosting an input voltage to the predetermined voltage and a connector connected to a wiring for supplying power to the drive unit are further arranged on the electric circuit board closer to the housing than the core member; the high-voltage wiring connects the boost circuit and the connector; 7. The liquid ejection head according to any one of the first to sixth aspects.

[0111] [Configuration 7] The electric circuit board is a contact surface on which a terminal capable of receiving an electrical signal is arranged; a via hole capable of transmitting the electrical signal from the contact surface to the housing side across the core member; having 8. The liquid ejection head according to any one of the first to seventh aspects.

[0112] [Configuration 8] The diameter of the via hole is smaller than φ0.8, 8. The liquid ejection head according to configuration 7.

[0113] [Configuration 9] the driving unit is a pump capable of circulating liquid between the accommodation unit and the element substrate, The high-voltage wiring is applied with the predetermined voltage capable of driving the pump. 9. The liquid ejection head according to any one of the first to eighth aspects.

[0114] [Configuration 10] The storage unit and the pump are shielded by the housing. 10. The liquid ejection head according to configuration 9.

[0115] [Configuration 11] The predetermined voltage is 42.4 V or more. 10. The liquid ejection head according to configuration 9.

[0116] [Configuration 12] the drive unit is an energy generating element formed at a position corresponding to each of the plurality of ejection ports, and capable of generating energy used to eject liquid in response to receiving an ejection signal for ejecting liquid, The predetermined voltage capable of driving the energy generating element is applied to the high-voltage wiring. 12. The liquid ejection head according to any one of the first to eleventh aspects.

[0117] [Configuration 13] a flame-retardant material having a flame-retardant grade of V-1 or higher; a sealing material having a flame retardant grade of V-1 or higher; Further provided with the high-voltage wiring connects the electric circuit board and the element substrate; the electric circuit board and the high-voltage wiring are covered with the flame-retardant member, a gap between the high-voltage wiring and the flame-retardant member is covered with the sealing member; 13. The liquid ejection head according to claim 12.

[0118] [Configuration 14] Further provided with a flame retardant plate having a flame retardant grade of V-1 or higher, the flame-retardant plate is connected to a discharge port forming member in which the plurality of discharge ports are formed. 14. The liquid ejection head according to claim 12 or 13.

[0119] [Configuration 15] The flame retardant grade of the discharge port forming member is V-1 or higher. 15. A liquid ejection head according to configuration 14.

[0120] [Configuration 16] A liquid ejection head according to any one of configurations 1 to 15; a control unit that controls the driving of the liquid ejection head, A liquid ejection device characterized by:

Claims

1. A liquid ejection head capable of ejecting liquid, a storage section capable of storing a liquid; an element substrate including a plurality of ejection ports for ejecting the liquid supplied from the container; a drive unit that is driven by being supplied with power at a predetermined voltage; a housing that supports the element substrate, the housing portion, and the drive portion; an electric circuit board on which high-voltage wiring to which the predetermined voltage is applied is arranged; a flame-retardant part having a flame-retardant grade of V-1 or higher; Equipped with The electric circuit board includes a core member having a flame retardancy grade of V-1 or higher, the flame-retardant portion is disposed closer to the housing than the electric circuit board, The high-voltage wiring is disposed between the core member and the flame-retardant portion. A liquid ejection head characterized by:

2. the flame-retardant portion is a film, The high-voltage wiring is shielded by the film. The liquid ejection head according to claim 1 .

3. the flame-retardant portion is a part of the housing, the high-voltage wiring is shielded by the electric circuit board and a part of the housing; 3. The liquid ejection head according to claim 1.

4. In the electric circuit board, the high-voltage wiring is routed two-dimensionally closer to the housing than the core member.

3. The liquid ejection head according to claim 1.

5. In the electric circuit board, the high-voltage wiring is three-dimensionally routed closer to the housing than the core member.

3. The liquid ejection head according to claim 1.

6. a boost circuit for boosting an input voltage to the predetermined voltage and a connector connected to a wiring for supplying power to the drive unit are further arranged on the electric circuit board closer to the housing than the core member; the high-voltage wiring connects the boost circuit and the connector; 3. The liquid ejection head according to claim 1.

7. The electric circuit board is a contact surface on which a terminal capable of receiving an electrical signal is arranged; a via hole capable of transmitting the electrical signal from the contact surface to the housing side across the core member; having 3. The liquid ejection head according to claim 1.

8. The diameter of the via hole is smaller than φ0.

8. The liquid ejection head according to claim 7 .

9. the driving unit is a pump capable of circulating liquid between the accommodation unit and the element substrate, The high-voltage wiring is applied with the predetermined voltage capable of driving the pump.

3. The liquid ejection head according to claim 1.

10. The storage unit and the pump are shielded by the housing. The liquid ejection head according to claim 9 .

11. The predetermined voltage is 42.4 V or more. The liquid ejection head according to claim 9 .

12. the drive unit is an energy generating element formed at a position corresponding to each of the plurality of ejection ports, and capable of generating energy used to eject liquid in response to receiving an ejection signal for ejecting liquid, The predetermined voltage capable of driving the energy generating element is applied to the high-voltage wiring.

3. The liquid ejection head according to claim 1.

13. a flame-retardant material having a flame-retardant grade of V-1 or higher; a sealing member having a flame retardancy grade of V-1 or higher; Further provided with the high-voltage wiring connects the electric circuit board and the element substrate; the electric circuit board and the high-voltage wiring are covered with the flame-retardant member, a gap between the high-voltage wiring and the flame-retardant member is covered with the sealing member; The liquid ejection head according to claim 12.

14. Further provided with a flame retardant plate having a flame retardant grade of V-1 or higher, the flame-retardant plate is connected to a discharge port forming member in which the plurality of discharge ports are formed. The liquid ejection head according to claim 12.

15. The flame retardancy grade of the discharge port forming member is V-1 or higher. The liquid ejection head according to claim 14.

16. The liquid ejection head according to claim 1 or 2; a control unit that controls the driving of the liquid ejection head, A liquid ejection device characterized by:

Images