JP2019209595A - Liquid discharge head, liquid discharge unit, and liquid discharge device - Google Patents

Abstract

To improve bubble discharging properties in a common supply flow path.SOLUTION: A liquid discharge head includes: a plurality of pressure chambers 6 communicating with a plurality of liquid discharging nozzles 4 respectively; a common supply flow path 10 communicating with the plurality of pressure chambers 6; and a common recovery flow path 50 communicating with the plurality of pressure chambers 6. The liquid flows from the common supply flow path 10 to the common recovery flow path 50 through the pressure chambers 6. A partial flow path portion 50B of the common recovery flow path 50 is disposed above the common supply flow path 10, and is provided with a communication path 61 communicating from the common supply flow path 10 to the common recovery flow path 50.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a liquid discharge head, a liquid discharge unit, and an apparatus for discharging liquid.

  The liquid discharge head (hereinafter also simply referred to as “head”) has a supply channel to a pressure chamber (individual liquid chamber) that communicates with the nozzle and a recovery channel that communicates with the individual liquid chamber. There is a flow-through type head (circulation type head) including a liquid supply port that communicates with a liquid discharge port that communicates with a recovery channel.

  Conventionally, for example, it has a supply-side common liquid chamber (common supply channel) that leads to a plurality of individual liquid chambers (pressure chambers) and a recovery-side common liquid chamber (common recovery channel) that leads to a plurality of individual liquid chambers, One in which a part of the supply side common liquid chamber and the recovery side common liquid chamber are arranged side by side is known (Patent Document 1).

JP 2017-154490 A

  However, the configuration disclosed in Patent Document 1 has a problem that bubbles in the common supply channel remain in the common supply channel and are difficult to discharge.

  The present invention has been made in view of the above-described problems, and an object thereof is to improve the dischargeability of bubbles in a common supply flow path.

In order to solve the above-described problem, a liquid discharge head according to the present invention includes:
A plurality of pressure chambers respectively leading to a plurality of nozzles for discharging liquid;
A common supply flow path leading to the plurality of pressure chambers;
A common recovery flow path leading to the plurality of pressure chambers,
The liquid flows from the common supply channel to the common recovery channel through the pressure chamber,
A portion of the common recovery flow path is disposed above the common supply flow path;
A communication path from the common supply channel to the common recovery channel is provided.

  According to the present invention, it is possible to improve the discharge performance of bubbles in the common supply channel.

FIG. 2 is an external perspective explanatory view of the liquid discharge head according to the first embodiment of the present invention. It is sectional explanatory drawing of the direction (liquid chamber longitudinal direction) orthogonal to the nozzle arrangement direction of the head. FIG. 3 is a cross-sectional explanatory diagram in a direction (liquid chamber longitudinal direction) orthogonal to the nozzle arrangement direction of the head corresponding to the BB line in FIG. 2. 6 is a cross-sectional explanatory diagram in a direction (liquid chamber longitudinal direction) orthogonal to the nozzle arrangement direction of Comparative Example 1. FIG. FIG. 6 is a cross-sectional explanatory diagram in a direction (liquid chamber longitudinal direction) orthogonal to a nozzle arrangement direction of a liquid ejection head according to a second embodiment of the present invention. FIG. 10 is a cross-sectional explanatory view in the nozzle arrangement direction corresponding to the line AA of FIG. 2 of the liquid ejection head according to the third embodiment of the present invention. FIG. 10 is a cross-sectional explanatory view in the nozzle arrangement direction corresponding to the line AA in FIG. 2 of a liquid ejection head according to a fourth embodiment of the present invention. It is a schematic explanatory drawing of an example of the apparatus which discharges the liquid which concerns on this invention. It is a plane explanatory view of an example of a head unit of the device. It is a block explanatory view of an example of a liquid circulation device. It is principal part plane explanatory drawing of the other example of the apparatus which discharges the liquid which concerns on this invention. It is principal part side explanatory drawing of the apparatus. It is principal part plane explanatory drawing of the other example of the liquid discharge unit which concerns on this invention. It is front explanatory drawing of the further another example of the liquid discharge unit which concerns on this invention.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is an external perspective view illustrating the liquid ejection head according to the first embodiment, FIG. 2 is a cross-sectional explanatory view in a direction (liquid chamber longitudinal direction) orthogonal to the nozzle arrangement direction of the head, and FIG. FIG. 6 is a cross-sectional explanatory diagram in a direction (liquid chamber longitudinal direction) orthogonal to the nozzle arrangement direction of the head corresponding to line -B.

  In the liquid discharge head 100, a nozzle plate 1, a flow path plate 2, and a vibration plate member 3 as a wall surface member are laminated and joined. And the piezoelectric actuator 11 which displaces the diaphragm member 3, the common flow path member 20, and the cover 29 are provided.

  The nozzle plate 1 has a plurality of nozzles 4 that discharge liquid.

  The flow path plate 2 forms a pressure chamber 6 that communicates with the nozzle 4, a supply-side fluid resistance portion 7 that communicates with the pressure chamber 6, and a supply-side introduction portion 8 that communicates with the supply-side fluid resistance portion 7. The supply side introduction portion 8 communicates with the common supply flow path 10 formed by the common flow path member 20 through the supply side opening 9.

  The diaphragm member 3 is a wall surface member that forms the wall surface of the pressure chamber 6 of the flow path plate 2. The diaphragm member 3 has a two-layer structure (not limited), and is formed of a first layer that forms a thin portion from the flow path plate 2 side and a second layer that forms a thick portion, and the first layer is a pressure chamber. A deformable vibration region 30 is formed in a portion corresponding to 6.

  A piezoelectric actuator 11 including an electromechanical conversion element as a driving means (actuator means, pressure generating means) for deforming the vibration region 30 of the diaphragm member 3 is provided on the opposite side of the diaphragm member 3 from the pressure chamber 6. It is arranged.

  This piezoelectric actuator 11 has a piezoelectric member 12 bonded on a base member 13, and the piezoelectric member 12 is grooved by half-cut dicing, and a required number of columnar piezoelectric elements 12 A with respect to one piezoelectric member 12, 12B is formed in a comb shape at a predetermined interval.

  Here, the piezoelectric element 12A of the piezoelectric member 12 is a piezoelectric element that is driven by giving a drive waveform, and the piezoelectric element 12B is used as a mere support without giving a drive waveform. However, all the piezoelectric elements 12A and 12B are driven. It can also be used as a piezoelectric element.

  The piezoelectric element 12 </ b> A is joined to a convex portion 30 a that is an island-shaped thick portion formed in the vibration region 30 of the diaphragm member 3. Further, the piezoelectric element 12 </ b> B is joined to the convex portion 30 b which is a thick portion of the diaphragm member 3.

  The piezoelectric member 12 is formed by alternately laminating piezoelectric layers and internal electrodes. The internal electrodes are drawn out to end faces, external electrodes are provided, and the flexible wiring member 15 is connected to the external electrodes.

  Further, the flow path plate 2 forms a recovery side fluid resistance portion 57, a recovery side individual flow path 56, and a recovery side lead-out portion 58 along the surface direction of the flow path plate 2 communicating with each pressure chamber 6. . The recovery side lead-out portion 58 communicates with the common recovery flow path 50 formed by the common flow path member 20 through the recovery side opening 59 formed in the diaphragm member 3.

  The common flow path member 20 forms a common supply flow path 10 and a common recovery flow path 50, a supply port (supply port) 71 that supplies liquid to the common supply flow path 10 from an external circulation path, and an external circulation path And a recovery port (recovery port) 72 for recovering the liquid.

  In this liquid ejection head 100, for example, the piezoelectric element 12A contracts by lowering the voltage applied to the piezoelectric element 12A from the reference potential, the vibration region 30 of the diaphragm member 3 descends, and the volume of the pressure chamber 6 expands. Thus, the liquid flows into the pressure chamber 6.

  Thereafter, the voltage applied to the piezoelectric element 12A is increased to extend the piezoelectric element 12A in the stacking direction, and the vibration region 30 of the diaphragm member 3 is deformed in the direction toward the nozzle 4 to contract the volume of the pressure chamber 6. The liquid in the pressure chamber 6 is pressurized, and the liquid is discharged from the nozzle 4.

  Then, by returning the voltage applied to the piezoelectric element 12A to the reference potential, the vibration region 30 of the diaphragm member 3 is restored to the initial position, and the pressure chamber 6 expands to generate a negative pressure. The liquid is filled into the pressure chamber 6 from the passage 10. Therefore, after the vibration of the meniscus surface of the nozzle 4 is attenuated and stabilized, the operation for the next discharge is started.

  Further, the liquid not discharged from the nozzle 4 passes through the nozzle 4 and is discharged to the common recovery flow path 50 through the recovery side fluid resistance portion 57, the recovery side individual flow path 56, the recovery side derivation section 58 and the recovery side opening 59. The And it is again supplied to the common supply flow path 10 from the common collection flow path 50 through an external circulation path. Further, even when the liquid is not discharged, the liquid flows from the common supply flow path 10 to the common recovery flow path 50 and is supplied again to the common supply flow path 10 through an external circulation path.

  Note that the driving method of the head is not limited to the above example (pulling-pushing), and it is also possible to perform striking or pushing depending on the direction to which the driving waveform is given.

  Next, the supply-side common liquid chamber and the recovery-side common liquid chamber in this head will be described.

  The flow path portion 50A of the common recovery flow path 50 is arranged side by side with the common supply flow path 10 in a direction orthogonal to the nozzle arrangement direction. In addition, the flow path portion 50B, which is a part of the common recovery flow path 50, is disposed above the common supply flow path 10 and is not aligned with the common supply flow path 10 in the direction orthogonal to the nozzle arrangement direction. Yes.

  A communication path (communication flow path) 61 is provided from the top surface 10a of the common supply flow path 10 to the flow path portion 50B that is a part of the common recovery flow path 50.

  Since it comprised in this way, the bubble 300 which generate | occur | produced in the common supply flow path 10 or mixed was passed to the common collection | recovery flow path 50 via the communicating path 61 which faces the top | upper surface 10a of the common supply flow path 10 by buoyancy. Finally, it is discharged from the common recovery flow path 50 to the external circulation path.

  Thus, the bubble discharge property from the common supply channel can be improved.

  Here, Comparative Example 1 will be described with reference to FIG. FIG. 4 is an explanatory cross-sectional view along a direction orthogonal to the nozzle arrangement direction of the liquid ejection head according to Comparative Example 1.

  In Comparative Example 1, the flow path portion 10A of the common supply flow path 10 is aligned with the common recovery flow path 50 in a direction orthogonal to the nozzle arrangement direction, and the flow path portion 10B of the common supply flow path 10 is above the common recovery flow path 50. It is set as the structure arrange | positioned.

  In the configuration of Comparative Example 1, the bubbles 300 adhering to the top surface 10a of the common supply channel 10 stay without being discharged.

  Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 5 is a cross-sectional explanatory diagram along a direction orthogonal to the nozzle arrangement direction of the liquid ejection head according to the second embodiment.

  In the present embodiment, a communication path 61 that communicates with the common recovery channel 50 is provided on the side wall (a partition wall with the common recovery channel 50) 20 a along the top surface 10 a of the common supply channel 10.

  By comprising in this way, the communication path 61 can be formed easily by forming the common flow path member 20 by laminating a plurality of plate-like members.

  Next, a third embodiment of the present invention will be described with reference to FIG. FIG. 6 is a cross-sectional explanatory view along the nozzle arrangement direction corresponding to the line AA of FIG. 2 of the liquid ejection head according to the third embodiment.

  In the present embodiment, a supply port (supply port) 71 through which liquid is supplied from the outside is disposed on one end side in the nozzle arrangement direction of the common supply channel 10, and the nozzles of the common supply channel 10 A communication path 61 communicating with the common recovery channel 50 is disposed on the other end side in the arrangement direction.

  In the liquid discharge head 100, the liquid supplied from the supply port 71 to the common supply flow path 10 flows into the common recovery flow path 50 through the pressure chamber 6 and flows from the communication path 61 to the common recovery flow path 50.

  As a result, even if bubbles flow into the common supply channel 10, the bubbles are discharged from the other end downstream of the flow of the common supply channel 10 to the common recovery channel 50, and the head 100 Bubbles are discharged to the outside.

  Here, when the liquid is circulated by generating a differential pressure ΔP between the supply port 71 and the recovery port 72 by the liquid circulation device, the flow rate flowing through the pressure chamber 6 and the communication path 61 is determined by the differential pressure ΔP. come.

  At this time, if the communication path 61 is too narrow, the bubbles may remain in the communication path 61 due to the surface tension when the bubbles are blocked in the communication path 61.

  Therefore, it is necessary to increase the diameter of the communication path 61 so that the meniscus holding force Pm of the bubbles in the communication path 61 becomes smaller with respect to the set differential pressure ΔP.

  In this case, the equivalent circular pipe diameter of the communication path 61 has a relationship of 4T / d <ΔP with respect to the equivalent circular pipe diameter d of the communication path 61 and the surface tension T of the liquid, or ΔP> Pm. The differential pressure ΔP is set as follows.

  Thereby, bubbles can be prevented from staying in the communication path 61.

  In addition, control of the flow volume which flows through the communicating path 61 lengthens the length of the communicating path 61, and sets a fluid resistance value.

  Next, a fourth embodiment of the present invention will be described with reference to FIG. FIG. 7 is a cross-sectional explanatory view along the nozzle arrangement direction corresponding to the line AA of FIG. 2 of the liquid discharge head according to the fourth embodiment.

  In the present embodiment, the supply ports (supply ports) 71 and 71 to which liquid is supplied from the outside are disposed on both ends of the common supply channel 10 in the nozzle arrangement direction. A communication path 61 communicating with the common recovery flow path 50 is disposed at the center in the nozzle arrangement direction.

  In the liquid discharge head 100, the liquid supplied from the supply ports 71 and 71 to the common supply flow path 10 flows to the common recovery flow path 50 through the pressure chamber 6 and flows from the communication path 61 to the common recovery flow path 50.

  As a result, even if bubbles flow into the common supply flow path 10, the bubbles are discharged from the central portion downstream of the flow of the common supply flow path 10 to the common recovery flow path 50, and the outside of the head 100 through the recovery port 72. Bubbles are discharged.

  In the above embodiment, a plurality of communication paths may be provided, or a combination of single-side supply and double-side discharge may be performed.

  Next, an example of a device for ejecting liquid according to the present invention will be described with reference to FIGS. FIG. 8 is a schematic explanatory view of the apparatus, and FIG. 9 is an explanatory plan view of an example of a head unit of the apparatus.

  The printing apparatus 500, which is a device for discharging the liquid, includes a carry-in means 501 for carrying in the continuous body 510, a guide carrying means 503 for guiding and carrying the continuous body 510 carried from the carry-in means 501 to the printing means 505, and a continuous body. A printing unit 505 that performs printing to form an image by discharging a liquid to 510, a drying unit 507 that dries the continuum 510, and an unloading unit 509 that unloads the continuum 510 are provided.

  The continuous body 510 is fed out from the original winding roller 511 of the carry-in means 501, guided and conveyed by the rollers of the carry-in means 501, the guide conveyance means 503, the drying means 507, and the carry-out means 509, and the take-up roller 591 of the carry-out means 509. It is wound up by.

  The continuous member 510 is transported on the transport guide member 559 by the printing unit 505 so as to face the head unit 550 and the head unit 555, and an image is formed by the liquid ejected from the head unit 550. Post-processing is performed with the processing liquid.

  Here, the head unit 550 includes, for example, full-line head arrays 551A, 551B, 551C, and 551D for four colors from the upstream side in the transport direction (hereinafter referred to as “head array 551” when colors are not distinguished). Is arranged.

  Each head array 551 is a liquid ejecting unit, and ejects black K, cyan C, magenta M, and yellow Y liquids to the transported continuous body 510, respectively. The type and number of colors are not limited to this.

  The head array 551 includes, for example, the liquid ejection heads according to the present invention (which are also simply referred to as “heads”) 100 arranged in a staggered manner on the base member 552, but is not limited thereto.

  Next, an example of the liquid circulation device will be described with reference to FIG. FIG. 10 is a block diagram of the circulation device. Although only one head is illustrated here, when a plurality of heads are arranged, a supply-side liquid path and a recovery-side liquid path are respectively provided on the supply side and the recovery side of the plurality of heads via a manifold or the like. Will be connected.

  The liquid circulation device 600 includes a supply tank 601, a recovery tank 602, a main tank 603, a first liquid feed pump 604, a second liquid feed pump 605, a compressor 611, a regulator 612, a vacuum pump 621, a regulator 622, and a supply side pressure sensor 631. And a recovery-side pressure sensor 632.

  Here, the compressor 611 and the vacuum pump 621 constitute means for generating a differential pressure between the pressure in the supply tank 601 and the pressure in the recovery tank 602.

  The supply-side pressure sensor 631 is connected between the supply tank 601 and the head 100 and connected to a supply-side liquid path connected to the supply port 71 of the head 100. The recovery side pressure sensor 632 is connected between the head 1 and the recovery tank 602 and is connected to a recovery side liquid path connected to the recovery port 72 of the head 100.

  One of the recovery tanks 602 is connected to the supply tank 601 via the first liquid feed pump 604, and the other of the recovery tanks 602 is connected to the main tank 603 via the second liquid feed pump 605.

  As a result, the liquid flows from the supply tank 601 through the supply port 71 into the head 100 and is recovered from the recovery port 72 to the recovery tank 602, and the liquid is supplied from the recovery tank 602 to the supply tank 601 by the first liquid feed pump 604. By being sent, a circulation path through which the liquid circulates is configured.

  Here, a compressor 611 is connected to the supply tank 601 and is controlled so that a predetermined positive pressure is detected by the supply-side pressure sensor 631. On the other hand, a vacuum pump 621 is connected to the recovery tank 602 and is controlled so that a predetermined negative pressure is detected by the recovery side pressure sensor 632.

  Thereby, the negative pressure of the meniscus can be kept constant while circulating the liquid through the head 100.

  Further, when liquid is discharged from the nozzle 4 of the head 100, the amount of liquid in the supply tank 601 and the recovery tank 602 decreases. Therefore, the liquid is replenished from the main tank 603 to the recovery tank 602 using the second liquid feeding pump 605 as appropriate.

  The liquid replenishment timing from the main tank 603 to the recovery tank 602 is provided in the recovery tank 602 such that liquid replenishment is performed when the liquid level in the recovery tank 602 falls below a predetermined level. It can be controlled by the detection result of a liquid level sensor or the like.

  Next, another example of a printing apparatus as an apparatus for ejecting a liquid according to the present invention will be described with reference to FIGS. FIG. 11 is an explanatory plan view of the main part of the apparatus, and FIG. 12 is an explanatory side view of the main part of the apparatus.

  The printing apparatus 500 is a serial type apparatus, and the carriage 403 is reciprocated in the main scanning direction by the main scanning moving mechanism 493. The main scanning movement mechanism 493 includes a guide member 401, a main scanning motor 405, a timing belt 408, and the like. The guide member 401 spans the left and right side plates 491A and 491B and holds the carriage 403 so as to be movable. The carriage 403 is reciprocated in the main scanning direction by the main scanning motor 405 via the timing belt 408 spanned between the driving pulley 406 and the driven pulley 407.

  The carriage 403 is equipped with a liquid discharge unit 440 in which the liquid discharge head 100 and the head tank 441 according to the present invention are integrated. The liquid discharge head 100 of the liquid discharge unit 440 discharges, for example, yellow (Y), cyan (C), magenta (M), and black (K) liquids. Further, the liquid ejection head 100 is mounted with a nozzle row composed of a plurality of nozzles arranged in the sub-scanning direction orthogonal to the main scanning direction, and the ejection direction facing downward.

  The liquid discharge head 100 is connected to the liquid circulation device 600 described above, and a liquid of a required color is circulated and supplied.

  The printing apparatus 500 includes a transport mechanism 495 for transporting the paper 410. The transport mechanism 495 includes a transport belt 412 serving as transport means, and a sub-scanning motor 416 for driving the transport belt 412.

  The conveyance belt 412 adsorbs the sheet 410 and conveys it at a position facing the liquid ejection head 100. The transport belt 412 is an endless belt and is stretched between the transport roller 413 and the tension roller 414. The adsorption can be performed by electrostatic adsorption or air suction.

  The transport belt 412 rotates in the sub-scanning direction when the transport roller 413 is rotationally driven by the sub-scanning motor 416 via the timing belt 417 and the timing pulley 418.

  Further, on one side of the carriage 403 in the main scanning direction, a maintenance / recovery mechanism 420 that performs maintenance / recovery of the liquid ejection head 100 is disposed on the side of the transport belt 412.

  The maintenance / recovery mechanism 420 includes, for example, a cap member 421 for capping the nozzle surface (surface on which the nozzle is formed) of the liquid ejection head 100, a wiper member 422 for wiping the nozzle surface, and the like.

  The main scanning movement mechanism 493, the maintenance / recovery mechanism 420, and the transport mechanism 495 are attached to a housing including the side plates 491A and 491B and the back plate 491C.

  In the printing apparatus 500 configured as described above, the paper 410 is fed and sucked onto the transport belt 412, and the paper 410 is transported in the sub-scanning direction by the circular movement of the transport belt 412.

Therefore, the liquid ejection head 100 is driven according to the image signal while moving the carriage 403 in the main scanning direction, thereby ejecting liquid onto the stopped paper 410 to form an image.

  Next, another example of the liquid discharge unit according to the present invention will be described with reference to FIG. FIG. 13 is an explanatory plan view of the main part of the unit.

  Among the members constituting the liquid discharge unit 440 and the apparatus for discharging the liquid, a housing portion constituted by side plates 491A, 491B and a back plate 491C, a main scanning movement mechanism 493, a carriage 403, and a liquid The discharge head 100 is configured.

  A liquid discharge unit in which the above-described maintenance / recovery mechanism 420 is further attached to, for example, the side plate 491B of the liquid discharge unit 440 can be configured.

  Next, still another example of the liquid discharge unit according to the present invention will be described with reference to FIG. FIG. 14 is an explanatory front view of the unit.

  The liquid discharge unit 440 includes a liquid discharge head 100 to which a flow path component 444 is attached, and a tube 456 connected to the flow path component 444.

  The flow path component 444 is disposed inside the cover 442. A head tank 441 may be included instead of the flow path component 444. In addition, a connector 443 that is electrically connected to the liquid discharge head 100 is provided above the flow path component 444.

  In the present application, the liquid to be ejected is not particularly limited as long as it has a viscosity and surface tension that can be ejected from the head, and the viscosity becomes 30 mPa · s or less at room temperature, normal pressure, or by heating and cooling. It is preferable. More specifically, solvents such as water and organic solvents, colorants such as dyes and pigments, functional materials such as polymerizable compounds, resins, and surfactants, and biocompatible materials such as DNA, amino acids, proteins, and calcium. , Edible materials such as natural pigments, etc., suspensions, emulsions, etc. These include, for example, inkjet inks, surface treatment liquids, components of electronic elements and light emitting elements, and formation of electronic circuit resist patterns It can be used in applications such as a liquid for use, a material liquid for three-dimensional modeling.

  As energy generation sources for discharging liquid, piezoelectric actuators (laminated piezoelectric elements and thin film piezoelectric elements), thermal actuators using electrothermal transducers such as heating resistors, electrostatic actuators consisting of a diaphragm and counter electrode are used. To be included.

  The “liquid ejection unit” is a unit in which functional parts and mechanisms are integrated with a liquid ejection head, and includes an assembly of parts related to liquid ejection. For example, the “liquid discharge unit” includes a head tank, a carriage, a supply mechanism, a maintenance / recovery mechanism, a main scanning movement mechanism, and a liquid circulation device in which at least one of the configurations of the liquid circulation unit is combined.

  Here, the term “integrated” refers to, for example, a liquid discharge head, a functional component, and a mechanism that are fixed to each other by fastening, adhesion, engagement, etc., and one that is held movably with respect to the other. Including. Further, the liquid discharge head, the functional component, and the mechanism may be configured to be detachable from each other.

  For example, there is a liquid discharge unit in which a liquid discharge head and a head tank are integrated. Also, there are some in which the liquid discharge head and the head tank are integrated by being connected to each other by a tube or the like. Here, a unit including a filter may be added between the head tank and the liquid discharge head of these liquid discharge units.

  In addition, there is a liquid discharge unit in which a liquid discharge head and a carriage are integrated.

  In addition, there is a liquid discharge unit in which the liquid discharge head and the scanning movement mechanism are integrated by holding the liquid discharge head movably on a guide member that constitutes a part of the scanning movement mechanism. In some cases, a liquid discharge head, a carriage, and a main scanning movement mechanism are integrated.

  Further, there is a liquid discharge unit in which a cap member that is a part of the maintenance / recovery mechanism is fixed to a carriage to which the liquid discharge head is attached, and the liquid discharge head, the carriage, and the maintenance / recovery mechanism are integrated. .

  In addition, there is a liquid discharge unit in which a tube is connected to a liquid discharge head to which a head tank or a flow path component is attached, and the liquid discharge head and a supply mechanism are integrated. The liquid from the liquid storage source is supplied to the liquid discharge head via this tube.

  The main scanning movement mechanism includes a guide member alone. The supply mechanism includes a single tube and a single loading unit.

  The “apparatus for ejecting liquid” includes an apparatus that includes a liquid ejection head or a liquid ejection unit and that ejects liquid by driving the liquid ejection head. The apparatus for ejecting a liquid includes not only an apparatus capable of ejecting a liquid to an object to which the liquid can adhere, but also an apparatus for ejecting the liquid into the air or liquid.

  This “apparatus for discharging liquid” may include means for feeding, transporting, and discharging a liquid to which liquid can adhere, as well as a pre-processing apparatus and a post-processing apparatus.

  For example, as a “liquid ejecting device”, an image forming device that forms an image on paper by ejecting ink, a powder is formed in layers to form a three-dimensional model (three-dimensional model) There is a three-dimensional modeling apparatus (three-dimensional modeling apparatus) that discharges a modeling liquid onto the powder layer.

  Further, the “apparatus for ejecting liquid” is not limited to an apparatus in which significant images such as characters and figures are visualized by the ejected liquid. For example, what forms a pattern etc. which does not have a meaning in itself, and what forms a three-dimensional image are also included.

  The above-mentioned “applicable liquid” means that the liquid can be attached at least temporarily and adheres and adheres, or adheres and penetrates. Specific examples include recording media such as paper, recording paper, recording paper, film, and cloth, electronic parts such as electronic substrates and piezoelectric elements, powder layers (powder layers), organ models, and test cells. Yes, unless specifically limited, includes everything that the liquid adheres to.

  The material of the above-mentioned “material to which liquid can adhere” is not limited as long as liquid such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, ceramics can be adhered even temporarily.

  In addition, the “device for ejecting liquid” includes a device in which the liquid ejection head and the device to which the liquid can adhere move relatively, but is not limited thereto. Specific examples include a serial type apparatus that moves the liquid discharge head, a line type apparatus that does not move the liquid discharge head, and the like.

  In addition, as the “device for ejecting liquid”, other than the above, a treatment liquid coating apparatus that ejects a treatment liquid onto a sheet in order to apply the treatment liquid to the surface of the sheet for the purpose of modifying the surface of the sheet, There is an injection granulation apparatus that granulates raw material fine particles by spraying a composition liquid in which raw materials are dispersed in a solution through a nozzle.

  Note that the terms “image formation”, “recording”, “printing”, “printing”, “printing”, “modeling” and the like in the terms of the present application are all synonymous.

DESCRIPTION OF SYMBOLS 1 Nozzle plate 4 Nozzle 2 Flow path plate 3 Vibration plate member 6 Pressure chamber 10 Common supply flow path 11 Piezoelectric actuator 20 Common flow path member 50 Common recovery flow path 61 Communication path 100 Liquid discharge head 403 Carriage 440 Liquid discharge unit 500 Printing apparatus (Device for discharging liquid)
550 Head unit 600 Liquid circulation device

Claims (10)

A plurality of pressure chambers respectively leading to a plurality of nozzles for discharging liquid;
A common supply flow path leading to the plurality of pressure chambers;
A common recovery flow path leading to the plurality of pressure chambers,
The liquid flows from the common supply channel to the common recovery channel through the pressure chamber,
A portion of the common recovery flow path is disposed above the common supply flow path;
A liquid discharge head, wherein a communication path is provided from the common supply channel to the common recovery channel. The common supply channel is supplied with the liquid from one end side in the nozzle arrangement direction,
The liquid ejection head according to claim 1, wherein the communication path is disposed on the other end side in the nozzle arrangement direction. The common supply channel is supplied with the liquid from both ends in the nozzle arrangement direction,
The liquid ejection head according to claim 1, wherein the communication path is disposed at a central portion in a nozzle arrangement direction. 4. The liquid ejection head according to claim 1, wherein the communication path passes through a top surface of the common supply flow path and a part of the common recovery path. 5. The liquid ejection head according to claim 1, wherein the communication path passes through the common supply flow path, a side surface, and the common recovery path. A liquid discharge unit comprising the liquid discharge head according to claim 1. A head tank for storing liquid to be supplied to the liquid discharge head, a carriage on which the liquid discharge head is mounted, a supply mechanism for supplying liquid to the liquid discharge head, a maintenance / recovery mechanism for maintaining and recovering the liquid discharge head, and the liquid The liquid discharge unit according to claim 6, wherein at least one of a main scanning movement mechanism for moving the discharge head in the main scanning direction and the liquid discharge head are integrated. A liquid discharge head according to any one of claims 1 to 5, or a liquid discharge unit according to claim 6 or 7,
A differential pressure between the common supply channel and the common recovery channel of the liquid discharge head is ΔP,
When the meniscus holding force of the nozzle formed when the communication path is blocked by bubbles in the common supply flow path is Pm, the differential supply pressure ΔP satisfying ΔP> Pm, the common supply flow path, The liquid circulating apparatus, wherein the liquid is circulated in the order of the pressure chamber and the common recovery flow path. A liquid discharge head according to any one of claims 1 to 5, or a liquid discharge unit according to claim 6 or 7,
The liquid flows through the common recovery channel from the common supply channel through the pressure chamber,
The differential pressure between the common supply channel and the common recovery channel is ΔP,
The equivalent circular pipe diameter of the communication path is d,
When the surface tension of the liquid is T,
A liquid circulation apparatus characterized by satisfying a relationship of 4T / d <ΔP.   A liquid discharge head according to any one of claims 1 to 5, a liquid discharge unit according to claim 6 or 7, or a liquid circulation device according to claim 8 or 9, A device that discharges liquid.

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