JP2019135086A - Liquid discharge head, liquid discharge unit and liquid discharge device - Google Patents

Abstract

To provide a liquid discharge head in which the discharge speed of droplets discharged from each nozzle in the nozzle array comprising plural arranged nozzles is homogenized.SOLUTION: A liquid discharge head comprises: plural nozzles 4 discharging droplets; plural individual liquid chambers 6 communicating with the nozzles 4; plural diaphragm members 3 forming at least a part of each wall surface of the chambers 6; and the piezoelectric element members 12 connected to the diaphragm members 3 and having plural piezoelectric element columns 12A corresponding to plural chambers 6, respectively. The width W of each of plural piezoelectric element columns 12A in a nozzle arrangement direction becomes wide as the position of the column 12A heads for a central part from an end part in the nozzle arrangement direction. In other words, the width of the column 12A located at the central part in the nozzle arrangement direction is wider than that located at the end part.SELECTED DRAWING: Figure 4

Description

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

  As an image forming apparatus such as a printer, a facsimile, a copying machine, a plotter, or a complex machine of these, for example, a liquid discharge recording type image forming using a recording head composed of a liquid discharge head (droplet discharge head) that discharges ink droplets. An apparatus (for example, an ink jet recording apparatus) is known.

  This liquid discharge recording type image forming apparatus means that ink droplets are transported from a recording head (not limited to paper, including OHP, and can be attached to ink droplets and other liquids). Yes, it is also ejected to a recording medium or a recording medium, recording paper, recording paper, etc.) to form an image (recording, printing, printing, and printing are also used synonymously). And a serial type image forming apparatus that forms an image by ejecting liquid droplets while the recording head moves in the main scanning direction, and a line type head that forms images by ejecting liquid droplets without moving the recording head There are line type image forming apparatuses using

  The liquid discharge head includes an individual liquid chamber (also referred to as a pressure generation chamber) that communicates with a nozzle from which droplets are discharged, and pressure generation means (actuator means) for generating pressure to pressurize the liquid in the individual liquid chamber ) Using a so-called piezoelectric actuator that uses a piezoelectric element and discharges droplets by changing the volume / pressure in the liquid chamber.

As a laminated piezoelectric element member, there is an elongated one in which a plurality of columnar piezoelectric elements (piezoelectric element columns) formed by grooving at a predetermined pitch are used and a plurality of piezoelectric element members are arranged on a substrate.
However, with the elongated piezoelectric element member, it is difficult to make the displacement characteristics of the piezoelectric element columns equal in any part, and in particular, the amount of displacement at both ends tends to be different from other areas. It is done. As a result, the discharge characteristics of the droplets may vary.

  In addition, it is desirable that the discharge speeds of the liquid droplets discharged from the plurality of nozzles of the liquid discharge head are the same for all the nozzles. There is a problem that the discharge speed of the liquid droplets varies.

  In order to solve this problem, a technology that suppresses variation in displacement by adopting an island structure having a highly rigid portion in a part of the diaphragm and a technology that widens the width of the piezoelectric elements at both ends (for example, see Patent Document 1). Etc. have been proposed.

  Patent Document 1 discloses that the width of piezoelectric elements located at or near both ends of a row of piezoelectric elements is formed to be 10 to 30% wider than the width of the remaining piezoelectric elements. Due to the characteristics of the piezoelectric element whose cross-sectional area increases in proportion to the size, the performance of the piezoelectric element located at both ends of the row is inferior or the ink temperature drops at both ends received by the atmosphere. It is described that an ink jet print head can be obtained in which the characteristics of all of the piezoelectric elements and thus the nozzle characteristics are made uniform.

In a conventional liquid discharge head, there may be a phenomenon in which the droplet velocity gently decreases from the end in the nozzle arrangement direction to the center. For example, when the relationship between the position of the nozzle in the arrangement direction and the droplet discharge speed from each nozzle is shown in a graph, it may be a bow-like graph as shown in FIG.
Such a phenomenon cannot be solved only by forming the width of the piezoelectric element at both ends or in the vicinity of both ends as in Patent Document 1.

  If there is a variation in the droplet discharge speed from each nozzle as described above, the landing position of the droplet on a target such as a recording medium will vary, and the image quality of the image formed in an image forming apparatus or the like Cause deterioration.

  Accordingly, an object of the present invention is to provide a liquid discharge head in which the discharge speed of droplets discharged from each nozzle in a nozzle row in which a plurality of nozzles are arranged is uniform.

  In order to solve the above problems, a liquid discharge head according to the present invention includes a plurality of nozzles that discharge droplets, a plurality of individual liquid chambers that communicate with the nozzles, and at least a part of a wall surface of the individual liquid chambers. And a piezoelectric element member connected to the diaphragm member and having a plurality of piezoelectric element columns corresponding to each of the plurality of individual liquid chambers, and a nozzle arrangement direction of the plurality of piezoelectric element columns The width of is increased as the position goes from the end in the nozzle arrangement direction toward the center. A plurality of nozzles for discharging liquid droplets, a plurality of individual liquid chambers communicating with the nozzles, a diaphragm member forming at least a part of a wall surface of the individual liquid chambers, and the diaphragm member, A piezoelectric element member having a plurality of piezoelectric element columns corresponding to each of the plurality of individual liquid chambers, and the width of the piezoelectric element column located at the center in the nozzle arrangement direction is the piezoelectric located at the end It is characterized by being larger than the width of the element column.

  ADVANTAGE OF THE INVENTION According to this invention, the liquid discharge head by which the discharge speed of the droplet discharged from each nozzle of the nozzle row | line | column with which the several nozzle was arranged was equalized can be provided.

FIG. 3 is an external perspective view of the head for explaining an example of a liquid discharge head. FIG. 2 is a cross-sectional explanatory view in a direction (liquid chamber longitudinal direction) orthogonal to a nozzle arrangement direction along the line XX in FIG. 1. FIG. 2 is a cross-sectional explanatory diagram in a nozzle arrangement direction (liquid chamber short direction) along line YY in FIG. 1. Sectional views (A) to (C) in the nozzle arrangement direction showing an example of the liquid discharge head according to the present invention, and a graph (D) showing the relationship between the width of the driving piezoelectric element column and the width of the groove in the nozzle arrangement direction It is. Sectional views (A) to (C) in the nozzle arrangement direction showing an example of the liquid discharge head according to the present invention, and a graph (D) showing the relationship between the width of the driving piezoelectric element column and the width of the groove in the nozzle arrangement direction It is. FIG. 2 is an explanatory side view illustrating the entire configuration of a mechanism unit of an image forming apparatus as an example of an apparatus for ejecting liquid according to the present invention. It is principal part plane explanatory drawing of the mechanism part. It is a graph which shows the relationship between the position of the nozzle and the discharge speed in the conventional liquid discharge head.

  Hereinafter, a liquid discharge head, a liquid discharge unit, and a device for discharging a liquid according to the present invention will be described with reference to the drawings. The present invention is not limited to the embodiments described below, and other embodiments, additions, modifications, deletions, and the like can be changed within a range that can be conceived by those skilled in the art, and any aspect is possible. As long as the functions and effects of the present invention are exhibited, the scope of the present invention is included.

An embodiment of a liquid discharge head will be described with reference to FIGS.
1 is an explanatory perspective view of the appearance of the liquid ejection head, FIG. 2 is a sectional explanatory view in a direction (longitudinal direction of the liquid chamber) perpendicular to the nozzle arrangement direction along the line XX in FIG. 1, and FIG. It is sectional explanatory drawing of the nozzle arrangement direction (liquid chamber short direction) in alignment with Y line.

  In FIG. 1, the nozzle at one end in the nozzle row is indicated as N1 (first nozzle), and the nozzle at the other end is indicated as Nn (nth nozzle). Na has shown the nozzle of the center part (substantially center part).

The liquid discharge head of the present invention includes a plurality of nozzles 4 that discharge droplets, a plurality of individual liquid chambers 6 that communicate with the nozzles 4, and a diaphragm member 3 that forms at least a part of the wall surface of the individual liquid chamber 6. The piezoelectric element member 12 is connected to the diaphragm member 3 and has a plurality of piezoelectric element columns 12A corresponding to the individual liquid chambers 6 respectively.
The piezoelectric element member 12 includes a first piezoelectric element column 12A that is a piezoelectric element column corresponding to each of the individual liquid chambers 6, and a second piezoelectric element column 12B that is adjacent to the first piezoelectric element column via a groove 12C. And have.
In addition, a power supply member having the electrode 15 is provided, and the electrode 15 is connected to one of the piezoelectric element columns. In the present embodiment, the electrode 15 is connected to the first piezoelectric element column 12A.

  In the liquid discharge head, a nozzle plate 1, a flow path plate (liquid chamber substrate) 2, and a vibration plate member 3 as a thin film member are laminated and joined. A piezoelectric actuator for displacing the diaphragm member 3 and a frame member 20 as a common flow path member constituting the frame of the head are provided.

  Fluid that supplies liquid to the individual liquid chamber (also referred to as pressure generation chamber) 6 and the individual liquid chamber 6 connected to the plurality of nozzles 4 that discharge droplets by the nozzle plate 1, the flow path plate 2, and the vibration plate member 3. A liquid supply path 7 also serving as a resistance part and a liquid introduction part 8 connected to the liquid supply path 7 are formed.

  Then, from the common liquid chamber 10 as a common flow path of the frame member 20 through the filter section 9 formed in the diaphragm member 3 as an ink inlet, the liquid introduction section 8 and the liquid supply path 7 are passed to a plurality of individual liquid chambers 6. Supply liquid.

The nozzle plate 1 is formed with a large number of nozzles 4 that are fine discharge ports for causing ink droplets to fly.
As a material of the nozzle plate 1, a metal member, a resin member, a laminated member of a resin layer and a metal layer, or the like can be used. For example, the nozzle plate 1 is manufactured from a nickel (Ni) metal plate by an electroforming method (electroforming). And a stainless steel material formed by press working.

The diameter of the nozzle 4 can be about 10 to 35 μm, preferably about 20 to 35 μm.
The nozzle 4 can be tapered and can be formed to have a pitch of 150 dpi.
Further, a water repellent layer may be provided on the droplet discharge side surface (surface in the discharge direction) of the nozzle plate 1.

The flow path plate 2 is joined to the nozzle plate 1.
Examples of the material of the flow path plate 2 include a metal plate and a single crystal silicon substrate.
For example, the individual liquid chamber 6, the liquid supply path 7, and the liquid introduction part 8 are obtained by performing processing such as pressing or etching (for example, etching with an acidic etching solution) on a stainless material or etching a single crystal silicon substrate. Etc. can be formed. The part left by the processing becomes the partition wall 5 that defines the individual liquid chamber 6. The liquid supply path 7 also serving as the fluid resistance portion can be formed by narrowing the punching width.

The vibration plate member 3 also serves as a wall surface member that forms the wall surface of the individual liquid chamber 6 of the flow path plate 2, and includes a deformable vibration region 30 in a portion corresponding to the individual liquid chamber 6.
The diaphragm member 3 includes a thin film diaphragm portion 3b, an island-shaped convex portion (island portion) 3a, a thick film portion including a beam, and a filter portion 9 serving as an ink inflow port. It is formed by stacking two layers of the formed nickel alloy plating film.

  On the opposite side of the diaphragm member 3 from the individual liquid chamber 6, a piezoelectric actuator including an electromechanical transducer as a driving means (actuator means, pressure generating means) for deforming the vibration region 30 of the diaphragm member 3 is disposed. Yes.

This piezoelectric actuator has a plurality of laminated piezoelectric element members (hereinafter also referred to as “laminated piezoelectric elements”) 12 bonded on a base member 13 with an adhesive. The laminated piezoelectric element 12 is grooved by half-cut dicing, and a required number of piezoelectric pillars 12A and 12B are formed in a comb shape at a predetermined interval with respect to one laminated piezoelectric element 12.
Examples of the material of the base member 13 include stainless steel.

The first piezoelectric column 12A and the second piezoelectric column 12B of the laminated piezoelectric element 12 are the same, but the piezoelectric column connected to the electrode 15 and driven by applying a driving waveform is a driving piezoelectric element column (driving unit). ), A piezoelectric column used as a simple column without giving a driving waveform can be distinguished as a non-driving piezoelectric element column (non-driving unit).
In the present embodiment, since the electrode 15 is connected to the first piezoelectric element column 12A, which is every other piezoelectric element column corresponding to each of the individual liquid chambers 6, the first piezoelectric element column is driven piezoelectrically. Although the element column 12A and the second piezoelectric element column will be described as driven piezoelectric element columns 12B, the configuration of the piezoelectric element member 12 is not limited to this.

  The drive piezoelectric element column 12 </ b> A is joined to an island-shaped convex portion (island portion) 3 a formed in the vibration region 30 of the diaphragm member 3. Examples of the bonding method include a method of patterning and bonding an adhesive layer including a bonding gap material.

The laminated piezoelectric element 12 is formed by alternately laminating piezoelectric layers and internal electrodes. The internal electrodes are drawn out to the end faces and external electrodes are provided, and a drive signal is given to the external electrodes of the drive piezoelectric element column 12A. For this purpose, an electrode 15 (FPC as a flexible wiring board having flexibility) is connected.
As a result, application of the drive voltage to the drive piezoelectric element column 12A is controlled.

The frame member 20 is formed with an ink supply port 11 and a common liquid chamber 10 through which liquid is supplied from a head tank or a liquid cartridge (not shown).
The frame member 20 may be formed by injection molding with, for example, epoxy resin or thermoplastic resin such as polyphenylene sulfite, or may be formed by cutting stainless steel. .
The frame member 20 made of a stainless material and the diaphragm member 3 are bonded together by patterning and bonding an adhesive layer including a gap material.

  In the liquid discharge head configured as described above, for example, a drive waveform composed of a pulse voltage of 10 to 50 V is applied to the drive piezoelectric element column 12A according to a recording signal, so that the drive piezoelectric element column 12A is stacked in the stacking direction. Displacement occurs, the individual liquid chamber 6 is pressurized via the diaphragm member 3, the pressure rises, and ink droplets are ejected from the nozzle 4.

  Specifically, the drive piezoelectric element column 12A contracts by lowering the voltage applied to the drive piezoelectric element column 12A from the reference potential, the vibration region 30 of the diaphragm member 3 descends, and the volume of the individual liquid chamber 6 expands. Then, the liquid flows into the individual liquid chamber 6, and then the voltage applied to the drive piezoelectric element column 12A is increased to extend the drive piezoelectric element column 12A in the stacking direction, so that the vibration region 30 of the diaphragm member 3 extends in the nozzle 4 direction. The liquid in the individual liquid chamber 6 is pressurized by being deformed to shrink the volume of the individual liquid chamber 6, and droplets are ejected (jetted) from the nozzle 4.

  Then, by returning the voltage applied to the drive piezoelectric element column 12A to the reference potential, the vibration region 30 of the diaphragm member 3 is restored to the initial position, and the individual liquid chamber 6 expands to generate a negative pressure. The liquid is filled into the individual liquid chamber 6 from the common liquid chamber 10 through the liquid supply path 7. Therefore, after the vibration of the meniscus surface of the nozzle 4 is attenuated and stabilized, the operation proceeds to the next droplet discharge.

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

In the configuration of the conventional liquid discharge head, there may be a variation in the droplet discharge speed from each nozzle, and the relationship between the nozzle position and the discharge speed tends to be a bow-like graph as shown in FIG. Seen.
The horizontal axis of the graph of FIG. 8 indicates the position in the nozzle arrangement direction, where the position of the nozzle N1 at one end is represented by “1” and the position of the nozzle Nn at the other end is represented by “n”. The vertical axis represents the ejection speed of droplets ejected from the nozzle.
As shown in the figure, as the nozzle position moves from both ends to the center, there is a decrease in the discharge speed that gradually decreases.

On the other hand, the liquid ejection head of the present embodiment is configured such that the width of the plurality of first piezoelectric element columns 12A in the nozzle arrangement direction increases as the position goes from the end in the nozzle arrangement direction to the center. Has been.
In addition, the width of the first piezoelectric element column 12A located at the central portion in the nozzle arrangement direction is larger than the width of the first piezoelectric element column 12A located at the end.

Increasing the width of the first piezoelectric element column (drive piezoelectric element column) 12A corresponding to the individual liquid chamber 6 increases the displacement area and also increases the area for pressing the island portion 3a. As a result, the volume of liquid that can be removed in the individual liquid chamber 6 also increases, and the discharge speed of the liquid droplets discharged from the nozzles also increases.
Therefore, the width of the first piezoelectric element column (drive piezoelectric element column) 12A is widest (thick) at the center in the nozzle arrangement direction, narrowest (thin) at both ends, and from the end toward the center. By adopting a structure that increases (thickens) according to the nozzle position, it is possible to improve the droplet discharge speed from the nozzle toward the center, and offset the decrease in discharge speed as shown in FIG. A uniform discharge speed can be realized.

The width W of the first piezoelectric element column (drive piezoelectric element column) 12A will be described.
As shown in FIG. 1, when the nozzle at one end in the nozzle row is expressed as N1 (first nozzle) and the nozzle at the other end is expressed as Nn (nth nozzle), The width of the first piezoelectric element column 12A corresponding to the nozzle N1 is expressed as W1, and the width of the first piezoelectric element column 12A corresponding to the nozzle Nn at the other end is expressed as Wn.
The value of n is not particularly limited, and can be appropriately selected according to the purpose (for example, required resolution). For example, n = 320.

When n is an even number, the numbers of the nozzles located in the center are n / 2 and n / 2 + 1. When these are represented by a and a + 1, the width of the first piezoelectric element column 12A corresponding to the center nozzle is Wa and It is expressed as Wa + 1, and the value of the width satisfies the relationship of the following formulas (1) to (2).
W1 <W2 <W3 <... <Wa Formula (1)
Wa≈Wa + 1 Formula (2)
Wa + 1>...>Wn-2>Wn-1> Wn Formula (3)
On the other hand, when n is an odd number, the number of the nozzle located at the center is (n + 1) / 2, and when this is represented by a, the width of the first piezoelectric element column 12A corresponding to the center nozzle is represented as Wa, The value of the width satisfies the relationship of the following expressions (4) and (5).
W1 <W2 <W3 <... <Wa Formula (4)
Wa>...>Wn-2>Wn-1> Wn Formula (5)

  As an aspect in which the width W of the first piezoelectric element column 12A satisfies the relationship of the above formulas (1) to (3) or (4) and (5), the first piezoelectric element column 12A and the second piezoelectric element are used. A first mode in which the width W of the first piezoelectric element column 12A is changed by adjusting the width G of the groove 12C between the element column 12B and the width G of the groove 12C is constant, and the position of the groove 12C There is a second mode in which the width W of the first piezoelectric element column 12A is changed by adjusting (pitch).

[First embodiment]
The piezoelectric element member 12 includes a first piezoelectric element column 12A corresponding to the individual liquid chamber 6, and a second piezoelectric element column 12B adjacent to the first piezoelectric element column via a groove 12C.
In the first aspect, the groove width G of the groove 12C in the nozzle arrangement direction becomes smaller as the position goes from the end in the nozzle arrangement direction to the center.
Further, the width G of the groove 12C located at the center in the nozzle arrangement direction is smaller than the width G of the groove 12C located at the end.

An example of this embodiment is shown in FIG.
4A is one end side (first side in FIG. 1), FIG. 4B is the center (region including the a-th in FIG. 1), and FIG. 4C is the other end side ( It is sectional drawing of the nozzle arrangement direction (direction which follows the YY line of FIG. 1) in the nth side of FIG.
FIG. 4D is a graph showing the relationship between the width W of the first piezoelectric element column (driving piezoelectric element column) 12A and the width G of the groove 12C in the nozzle arrangement direction.

The width W1 of the first piezoelectric element column 12A on one end side, the width Wn of the first piezoelectric element column 12A on the other end side, and the width Wa of the first piezoelectric element column 12A on the center are shown in FIG. As shown, W1 <W2 <Wa and Wn <Wn-1 <Wa.
Further, the width G1 of the groove portion 12C on one end side, the width Gn of the groove portion 12C on the other end side, and the width Ga of the central groove portion 12C are G1>G2> Ga, Gn> as shown in FIG. Gn-1> Ga.

By processing so that the width G of the groove portion 12C decreases toward the center portion, the width W of the first piezoelectric element column 12A increases toward the center portion. The element member 12 is obtained.
Examples of the processing method of the groove 12C include dicing processing and wire cutting processing.

[Second embodiment]
The piezoelectric element member 12 includes a first piezoelectric element column 12A corresponding to the individual liquid chamber 6, and a second piezoelectric element column 12B adjacent to the first piezoelectric element column via a groove 12C.
In the second aspect, the groove width G in the nozzle array direction of the groove 12C is constant. In the nozzle arrangement direction, the distance between the pair of grooves 12C that define the first piezoelectric element column 12A increases from the end in the nozzle arrangement direction toward the center.

An example of this embodiment is shown in FIG.
5A is one end side (first side in FIG. 1), FIG. 5B is the center (a region including the a-th in FIG. 1), and FIG. 5C is the other end side ( It is sectional drawing of the nozzle arrangement direction (direction which follows the YY line of FIG. 1) in the nth side of FIG.
FIG. 5D is a graph showing the relationship between the width W of the first piezoelectric element column (driving piezoelectric element column) 12A and the width G of the groove 12C in the nozzle arrangement direction.

The width W1 of the first piezoelectric element column 12A on one end side, the width Wn of the first piezoelectric element column 12A on the other end side, and the width Wa of the first piezoelectric element column 12A on the center are shown in FIG. As shown, W1 <W2 <Wa and Wn <Wn-1 <Wa.
The width G1 of the groove 12C on one end side, the width Gn of the groove 12C on the other end side, and the width Ga of the central groove 12C are constant as shown in FIG. 6 (G1 = Ga = Gn). However, the interval (pitch) in the nozzle arrangement direction of the pair of grooves 12C that define the first piezoelectric element column 12A is different.

The pitch of the grooves 12C is determined so that the width W of the first piezoelectric element column 12A gradually increases from the end side toward the center side, and the piezoelectric element columns are formed. The piezoelectric element member 12 which comprises is obtained.
In this embodiment, since the process of adjusting the width G of the groove 12C is not required, it is possible to easily manufacture the piezoelectric element member 12 in which the width W of the first piezoelectric element column 12A increases toward the center. .

In the liquid ejection head according to this embodiment, the ejection speed of the liquid droplets ejected from each nozzle of the nozzle array in which a plurality of nozzles are arranged is uniform, so that the liquid droplets to the target such as a recording medium Variations in landing positions are reduced. For example, when applied to a recording head of an image forming apparatus, it is possible to prevent deterioration in image quality of an image to be formed.
This embodiment can also be applied to a circulation type liquid discharge head that circulates ink in the individual liquid chamber.

Next, a liquid discharge unit and a device for discharging a liquid according to the present invention will be described.
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 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 diaphragms and counter electrodes 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 liquid includes not only an apparatus capable of ejecting liquid to an object to which liquid can adhere, but also an apparatus for ejecting liquid toward 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.

  Next, an embodiment of an apparatus for ejecting liquid according to the present invention will be described with reference to FIGS. FIG. 6 is an explanatory side view for explaining the overall configuration of the mechanism section of the apparatus, and FIG. 7 is an explanatory plan view of the main part of the mechanism section. In this embodiment, the image forming apparatus will be described as an example, but the present invention is not limited to this.

  This image forming apparatus is a serial type image forming apparatus, and a carriage 233 is slidably held in the main scanning direction by main and slave guide rods 231 and 232 which are guide members horizontally mounted on the left and right side plates 221A and 221B. The main scanning motor that does not perform moving scanning in the direction indicated by the arrow (carriage main scanning direction) via the timing belt.

  The carriage 233 includes a plurality of recording heads 234 including the liquid ejection head according to the present invention for ejecting ink droplets of each color of yellow (Y), cyan (C), magenta (M), and black (K). Nozzle rows consisting of these nozzles are arranged in the sub-scanning direction orthogonal to the main scanning direction, and are mounted with the ink droplet ejection direction facing downward.

  The recording head 234 is configured by attaching the liquid ejection heads 234a and 234b according to the present invention each having two nozzle rows to one base member, and one nozzle row of one head 234a is black (K). The other nozzle row is a cyan (C) droplet, one nozzle row of the other head 234b is a magenta (M) droplet, and the other nozzle row is a yellow (Y) droplet. , Respectively. Note that, here, a two-head configuration is used to eject four color droplets, but a liquid ejection head for each color may be provided.

  The carriage 233 is equipped with sub tanks 235a and 235b (referred to as “sub tank 235” when not distinguished) for supplying ink of each color corresponding to the nozzle rows of the recording head 234. The sub tank 235 is supplied with ink of each color from the ink cartridge 210 of each color by the supply unit 224 via the supply tube 236 of each color.

  On the other hand, as a paper feed unit for feeding the paper 242 loaded on the paper stacking unit (pressure plate) 241 of the paper feed tray 202, a half-moon roller (feed) that feeds the paper 242 from the paper stacking unit 241 one by one. A separation pad 244 made of a material having a large coefficient of friction is provided opposite to the sheet roller 243 and the sheet feeding roller 243, and the separation pad 244 is urged toward the sheet feeding roller 243 side.

  In order to feed the sheet 242 fed from the sheet feeding unit to the lower side of the recording head 234, a guide member 245 for guiding the sheet 242, a counter roller 246, a conveyance guide member 247, and a tip pressure roller. And a conveying belt 251 which is a conveying means for electrostatically attracting the fed paper 242 and conveying it at a position facing the recording head 234.

  The conveyor belt 251 is an endless belt, and is configured to wrap around the conveyor roller 252 and the tension roller 253 so as to circulate in the belt conveyance direction (sub-scanning direction). In addition, a charging roller 256 that is a charging unit for charging the surface of the transport belt 251 is provided. The charging roller 256 is disposed so as to come into contact with the surface layer of the conveyor belt 251 and to rotate following the rotation of the conveyor belt 251. The transport belt 251 rotates in the belt transport direction when the transport roller 252 is rotationally driven through timing by a sub-scanning motor (not shown).

  Further, as a paper discharge unit for discharging the paper 242 recorded by the recording head 234, a separation claw 261 for separating the paper 242 from the transport belt 251, a paper discharge roller 262, and a paper discharge roller 263 are provided. A paper discharge tray 203 is provided below the paper discharge roller 262.

  A double-sided unit 271 is detachably attached to the back surface of the apparatus main body. The duplex unit 271 takes in the paper 242 returned by the reverse rotation of the transport belt 251, reverses it, and feeds it again between the counter roller 246 and the transport belt 251. The upper surface of the duplex unit 271 is a manual feed tray 272.

  Further, a maintenance / recovery mechanism 281 for maintaining and recovering the nozzle state of the recording head 234 is disposed in the non-printing area on one side of the carriage 233 in the scanning direction. The maintenance / recovery mechanism 281 includes cap members (hereinafter referred to as “caps”) 282a and 282b (hereinafter referred to as “caps 282” when not distinguished) for capping each nozzle surface of the recording head 234, and nozzle surfaces. A wiper blade 283 that is a blade member for wiping the ink, and an empty discharge receiver 284 that receives liquid droplets when performing empty discharge for discharging liquid droplets that do not contribute to recording in order to discharge thickened ink. Yes.

  In addition, in the non-printing area on the other side of the carriage 233 in the scanning direction, idle ejection that receives droplets when performing idle ejection that ejects droplets that do not contribute to recording in order to discharge ink that has been thickened during recording or the like. A receiver 288 is disposed, and the idle discharge receiver 288 is provided with an opening 289 along the nozzle row direction of the recording head 234 and the like.

  In the image forming apparatus configured as described above, the sheets 242 are separated and fed one by one from the sheet feeding tray 202, and the sheet 242 fed substantially vertically upward is guided by the guide member 245, It is sandwiched between the counter roller 246 and conveyed, and further, the leading end is guided by the conveying guide 237 and pressed against the conveying belt 251 by the leading end pressure roller 249, and the conveying direction is changed by about 90 °.

  At this time, a positive output and a negative output are alternately applied to the charging roller 256, that is, an alternating voltage is applied, and a charging voltage pattern in which the conveying belt 251 alternates, that is, in the sub-scanning direction that is the circumferential direction. , Plus and minus are alternately charged in a band shape with a predetermined width. When the sheet 242 is fed onto the conveyance belt 251 charged alternately with plus and minus, the sheet 242 is attracted to the conveyance belt 251, and the sheet 242 is conveyed in the sub scanning direction by the circumferential movement of the conveyance belt 251.

  Therefore, by driving the recording head 234 according to the image signal while moving the carriage 233, ink droplets are ejected onto the stopped paper 242 to record one line, and after the paper 242 is conveyed by a predetermined amount, Record the next line. Upon receiving a recording end signal or a signal that the trailing edge of the paper 242 has reached the recording area, the recording operation is finished and the paper 242 is discharged onto the paper discharge tray 203.

1 Nozzle plate 2 Channel plate (liquid chamber substrate)
DESCRIPTION OF SYMBOLS 3 Diaphragm member 3a Island part 3b Diaphragm part 4 Nozzle 5 Partition 6 Individual liquid chamber 7 Liquid supply path 8 Liquid introduction part 9 Filter part 10 Common liquid chamber 11 Ink supply port 12 Piezoelectric element member (laminated piezoelectric element)
12A First piezoelectric element column (driving piezoelectric element column, driving unit)
12B Second piezoelectric element column (non-driving piezoelectric element column, non-driving part)
12C Groove 13 Base member 15 Electrode (FPC)
20 Frame member 30 Vibration region

JP-A-8-1928

Claims (7)

A plurality of nozzles for discharging droplets;
A plurality of individual liquid chambers that communicate with the nozzle;
A diaphragm member forming at least a part of the wall surface of the individual liquid chamber;
A piezoelectric element member connected to the diaphragm member and having a plurality of piezoelectric element columns corresponding to each of the plurality of individual liquid chambers;
The width of the plurality of piezoelectric element columns in the nozzle arrangement direction increases as the position thereof moves from the end to the center in the nozzle arrangement direction. A plurality of nozzles for discharging droplets;
A plurality of individual liquid chambers that communicate with the nozzle;
A diaphragm member forming at least a part of the wall surface of the individual liquid chamber;
A piezoelectric element member connected to the diaphragm member and having a plurality of piezoelectric element columns corresponding to each of the plurality of individual liquid chambers;
The liquid discharge head according to claim 1, wherein a width of the piezoelectric element column located in a central portion in the nozzle arrangement direction is larger than a width of the piezoelectric element column located in an end portion. The piezoelectric element member includes a first piezoelectric element column corresponding to the individual liquid chamber, and a second piezoelectric element column adjacent to the first piezoelectric element column via a groove portion,
2. The liquid ejection head according to claim 1, wherein the groove width in the nozzle arrangement direction of the groove portion decreases as the position thereof moves from an end portion in the nozzle arrangement direction toward a central portion. The piezoelectric element member includes a first piezoelectric element column corresponding to the individual liquid chamber, and a second piezoelectric element column adjacent to the first piezoelectric element column via a groove portion,
3. The liquid ejection head according to claim 2, wherein a width of the groove portion located at a central portion in the nozzle arrangement direction is smaller than a width of the groove portion located at an end portion. The piezoelectric element member includes a first piezoelectric element column corresponding to the individual liquid chamber, and a second piezoelectric element column adjacent to the first piezoelectric element column via a groove portion,
The liquid discharge head according to claim 1, wherein a groove width of the groove portion in the nozzle arrangement direction is constant.   A liquid discharge unit comprising the liquid discharge head according to claim 1.   An apparatus for ejecting liquid, comprising the liquid ejection head according to claim 1.