JP2017144660A - Liquid discharge head, liquid discharge unit and device for discharging liquid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve such the problem that discharging cannot be done through a circulation flow passage when a bubble is generated and clogs a nozzle communication passage.SOLUTION: A liquid discharge head includes: a nozzle 4 for discharging liquid; an individual liquid chamber 6 communicated to the nozzle 4; a nozzle communication passage 5 communicating the individual liquid chamber 6 to the nozzle 4, through which the liquid flows toward a side of the nozzle 4; and a circulation flow passage 41 communicated to the individual liquid chamber 6 via the nozzle communication passage 5. Miniaturization means 69 for miniaturizing a bubble is disposed in an inlet part on a side of the individual liquid chamber 6 of the nozzle communication passage 5. The miniaturization means 69 includes a plurality of through-holes 61.SELECTED DRAWING: Figure 2

Description

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

  Bubbles mixed in the individual liquid chamber by circulating the liquid that was not discharged among the liquid supplied to the individual liquid chamber through the circulation channel as a liquid discharge head (droplet discharge head) that discharges the liquid Circulating heads that improve the discharge performance of the liquid and suppress the change in the characteristics of the liquid are known.

  For example, an ink supply channel that supplies ink from an ink introduction port, an ink discharge channel that discharges ink to an ink discharge port, and a nozzle that discharges ink by connecting the ink supply channel and the ink discharge channel There is known an ink chamber having an ink chamber and a piezoelectric actuator that displaces a vibration plate of the ink chamber and applies pressure to the ink in the ink chamber (Patent Document 1).

JP 2011-218784 A

  However, even in the configuration in which the liquid is circulated, there is a problem that it is difficult to discharge the bubbles from the circulation flow path when large bubbles that completely block the individual liquid chamber are mixed and generated.

  This invention is made | formed in view of said subject, and aims at improving bubble discharge property.

In order to solve the above-described problem, a liquid discharge head according to the present invention includes:
A nozzle for discharging liquid;
An individual liquid chamber leading to the nozzle;
A nozzle communication path through the nozzle and the individual liquid chamber;
A circulation channel that leads to the individual liquid chamber via the nozzle communication path,
The micronization means for micronizing bubbles is arranged at the inlet portion of the nozzle communication path.

  According to the present invention, the bubble discharge property can be improved.

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. It is a plane explanatory view of the miniaturization means of the head. It is sectional explanatory drawing with which it uses for description of an effect | action of the said refinement | miniaturization means. 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 diagram in a direction (liquid chamber longitudinal direction) orthogonal to a nozzle arrangement direction of a liquid ejection head according to a third embodiment of the present invention. It is principal part plane explanatory drawing of an 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. An example of the liquid discharge head according to the first embodiment of the present invention will be described with reference to FIGS. 1 is an external perspective view of the liquid ejection head, 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. It is.

  In the liquid discharge head, a nozzle plate 1, a flow path plate 2, and a diaphragm 3 as a wall surface member are laminated and joined. And the piezoelectric actuator 11 which displaces the diaphragm 3, the frame member 20 as a common liquid chamber member, and the cover 21 are provided.

  The nozzle plate 1 has a plurality of nozzles 4 that discharge liquid. Here, there are two nozzle rows in which a plurality of nozzles 4 are arranged, but only the nozzles 4 included in one nozzle row are illustrated.

  The flow path plate 2 includes an individual liquid chamber 6 that communicates with the nozzle 4 via the nozzle communication path 5, a supply flow path side fluid resistance section 7 that communicates with the individual liquid chamber 6, and a liquid introduction section 8 that communicates with the supply flow path side fluid resistance section 7. Through-holes and grooves are formed. The nozzle communication path 5 is a flow path that communicates with the nozzle 4 and the individual liquid chamber 6. Further, the supply flow path side fluid resistance section 7 and the liquid introduction section 8 constitute a liquid supply flow path. Here, the flow path plate 2 is configured by laminating a plurality of plate-like members, but is not limited thereto.

  The vibration plate 3 has a deformable vibration region 30 that forms the wall surface of the individual liquid chamber 6 of the flow path plate 2.

  A piezoelectric actuator 11 including an electromechanical conversion element as a driving means (actuator means, pressure generating means) for deforming the diaphragm 3 is disposed on the opposite side of the diaphragm 3 from the individual liquid chamber 6.

  The piezoelectric actuator 11 has a required number of columnar piezoelectric elements (piezoelectric columns) 12 arranged at predetermined intervals along the nozzle arrangement direction, and the piezoelectric elements 12 are joined to the convex portions 30 a of the vibration region 30. Yes.

  The frame member 20 is formed with a common liquid chamber 10 to which liquid is supplied from a head tank or a liquid cartridge.

  Further, the flow path plate 2 has a groove portion serving as a circulation flow path 41 communicating with the nozzle communication passage 5 and a through hole serving as a passage 44 communicating with the circulation flow path 41 on the nozzle plate 1 side opposite to the individual liquid chamber 6. The passage 44 communicates with a circulation common liquid chamber 45 formed in the frame member 20.

  The frame member 20 is provided with a supply port 23 that communicates with the common liquid chamber 10 and a circulation port (discharge port) 46 that communicates with the circulation common liquid chamber 45.

  In the liquid discharge head configured as described above, for example, by lowering the voltage applied to the piezoelectric element 12 from the reference potential, the piezoelectric element 12 contracts, the vibration region 30 of the diaphragm 3 is drawn, and the volume of the individual liquid chamber 6 increases. By expanding, the liquid flows into the individual liquid chamber 6.

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

  Then, by returning the voltage applied to the piezoelectric element 12 to the reference potential, the vibration region 30 of the diaphragm 3 is restored to the initial position, and the individual liquid chamber 6 expands to generate a negative pressure. At this time, the common liquid chamber The individual liquid chamber 6 is filled with liquid from 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.

  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.

  And in this embodiment, the refinement | miniaturization means 60 which refine | miniaturizes a bubble is provided in the entrance part by the side of the separate liquid chamber 6 of the nozzle communicating path 5. FIG. As shown in FIG. 3, the miniaturization means 60 is provided with a plurality of through holes 61. The opening area of the through hole 61 is smaller than the minimum opening area of the nozzle 4 on the liquid ejection surface of the nozzle plate 1.

  By providing the finer means 60 in this way, as shown in FIG. 4A, even when bubbles 300 having a diameter larger than the opening area of the nozzle communication path 5 are mixed and generated in the individual liquid chamber 6, As shown in FIG. 4B, the bubbles 300 are divided into fine bubbles 301 by passing through the through holes 61 of the miniaturizing means 60.

  The refined bubbles 301 do not completely block the nozzle communication path 5 and can be discharged to the circulation common liquid chamber 45 side through the circulation channel 41.

  Thereby, bubble discharge property can be improved.

  Next, a liquid ejection head according to a second embodiment of the present invention will be described with reference to FIG. FIG. 5 is a cross-sectional explanatory view in a direction (liquid chamber longitudinal direction) orthogonal to the nozzle arrangement direction of the head.

  In the present embodiment, the nozzle 4 is disposed at a position for discharging the liquid in the direction of the liquid flow in the individual liquid chamber 6.

  And the opening part of the circulation flow path 41 is made to open in the side wall surface by the side of the nozzle 4 of the separate liquid chamber 6. FIG.

  Here, a refining means 60 for refining bubbles is arranged at the inlet portion of the circulation channel 41.

  Since it comprised in this way, a bubble can be refined | miniaturized and it can send in to the circulation flow path 41, the situation where a bubble block | closes the inlet_port | entrance part of the circulation flow path 41 and it becomes impossible to discharge can be prevented, and bubble discharge property can be improved.

  Next, a liquid ejection head according to a third embodiment of the invention will be described with reference to FIG. FIG. 6 is a cross-sectional explanatory view in a direction (liquid chamber longitudinal direction) orthogonal to the nozzle arrangement direction of the head.

  In the present embodiment, in the first embodiment, the filter unit 90 that removes foreign matters is disposed in the supply port 9 on the upstream side of the individual liquid chamber 6 that communicates from the common liquid chamber 10 to the liquid introduction unit 8. And the opening area of the filter hole 91 of the filter part 90 is made smaller than the opening area of the through-hole 61 of the refinement | miniaturization means 6. FIG.

  Thereby, it can suppress that a foreign material block | closes the through-hole 61 of the refinement | miniaturization means 6, and can perform stable discharge.

  Next, an example of an apparatus for ejecting liquid according to the present invention will be described with reference to FIGS. FIG. 7 is an explanatory plan view of the main part of the apparatus, and FIG. 8 is an explanatory side view of the main part of the apparatus.

  This apparatus is a serial type apparatus, and the carriage 403 reciprocates 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.

  A liquid discharge unit 440 in which the liquid discharge head 404 and the head tank 441 according to the present invention are integrated is mounted on the carriage 403. The liquid discharge head 404 of the liquid discharge unit 440 discharges, for example, yellow (Y), cyan (C), magenta (M), and black (K) liquids. The liquid ejection head 404 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 stored in the liquid cartridge 450 is supplied to the head tank 441 by the supply mechanism 494 for supplying the liquid stored outside the liquid discharge head 404 to the liquid discharge head 404.

  The supply mechanism 494 includes a cartridge holder 451 that is a filling unit for mounting the liquid cartridge 450, a tube 456, a liquid feeding unit 452 including a liquid feeding pump, and the like. The liquid cartridge 450 is detachably attached to the cartridge holder 451. Liquid is fed from the liquid cartridge 450 to the head tank 441 by the liquid feeding unit 452 via the tube 456.

  This apparatus 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 paper 410 and conveys it at a position facing the liquid ejection head 404. 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 404 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 404, a wiper member 422 for wiping the nozzle surface, and the like.

  The main scanning movement mechanism 493, the supply mechanism 494, 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 this apparatus 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 404 is driven in accordance with 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.

  Thus, since this apparatus includes the liquid ejection head according to the present invention, a high-quality image can be stably formed.

  Next, another example of the liquid discharge unit according to the present invention will be described with reference to FIG. FIG. 9 is an explanatory plan view of the main part of the unit.

  The liquid discharge unit includes a casing portion composed of side plates 491A and 491B and a back plate 491C, a main scanning moving mechanism 493, a carriage 403, and a liquid among the members constituting the liquid discharge device. The discharge head 404 is configured.

  Note that a liquid discharge unit in which at least one of the above-described maintenance and recovery mechanism 420 and the supply mechanism 494 is further attached to, for example, the side plate 491B of the liquid discharge unit may be configured.

  Next, still another example of the liquid discharge unit according to the present invention will be described with reference to FIG. FIG. 10 is an explanatory front view of the unit.

  This liquid discharge unit includes a liquid discharge head 404 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 ejection head 404 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, solutions, suspensions, emulsions, and the like. These include, for example, inkjet inks, surface treatment liquids, components of electronic devices and light emitting devices, and formation of electronic circuit resist patterns It can be used in applications such as liquids for use, three-dimensional modeling material liquids, and the like.

  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 combination of at least one of a head tank, a carriage, a supply mechanism, a maintenance / recovery mechanism, and a main scanning movement mechanism with a liquid discharge head.

  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.

  Also, 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 2 Flow path plate 3 Vibration plate 4 Nozzle 5 Nozzle communication path 6 Individual liquid chamber 7 Supply flow path side fluid resistance part 10 Common liquid chamber 11 Piezoelectric actuator 20 Frame member 41 Circulation flow path 45 Circulation common liquid chamber 403 Carriage 404 Liquid Discharge head 440 Liquid discharge unit

Claims (7)

A nozzle for discharging liquid;
An individual liquid chamber leading to the nozzle;
A nozzle communication path through the nozzle and the individual liquid chamber;
A circulation channel that leads to the individual liquid chamber via the nozzle communication path,
2. A liquid discharge head according to claim 1, wherein a micronization means for micronizing bubbles is disposed at an inlet portion of the nozzle communication path. A nozzle for discharging liquid;
An individual liquid chamber leading to the nozzle;
A circulation flow path leading to the individual liquid chamber,
A liquid discharge head characterized in that a micronization means for micronizing bubbles is disposed at an inlet portion of the circulation channel. The miniaturization means has a plurality of through holes,
The liquid discharge head according to claim 1, wherein an opening area of the through hole is smaller than a minimum opening area of the nozzle. A filter having a plurality of filter holes is arranged on the upstream side of the individual liquid chamber,
The liquid discharge head according to claim 3, wherein an opening area of the filter hole of the filter is smaller than an opening area of the through hole.   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 6. The liquid discharge unit according to claim 5, wherein the liquid discharge head is integrated with at least one of a main scanning movement mechanism that moves the discharge head in the main scanning direction.   An apparatus for ejecting liquid, comprising the liquid ejection head according to claim 1 or the liquid ejection unit according to claim 5 or 6.

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