JP5696934B2 - Liquid discharge head and image forming apparatus provided with the same - Google Patents

Description

  The present invention relates to a liquid discharge head that discharges liquid droplets from a large number of discharge ports, and an ink jet type image forming apparatus that forms an image by discharging liquid droplets onto a recording material using the liquid discharge head.

  This type of liquid discharge head is used as a recording head of an image forming apparatus such as a copying machine, a printer, a facsimile machine, or a plotter. The image forming apparatus here forms an image on a recording material, but the material of the recording material is not limited to paper, and is a thread, fiber, fabric, leather, metal, plastic, glass, It means an apparatus for forming an image by discharging a liquid onto any recording material such as wood or ceramics. Image formation not only applies an image having a meaning such as a character or a figure to a recording material, but also applies an image having no meaning such as a pattern to the recording material (simply ejects a droplet). ) Also means. The liquid ejected as droplets is not limited to so-called ink, and is not particularly limited as long as it becomes liquid when ejected, and includes, for example, DNA samples, resists, pattern materials, and the like. It is.

  In general, a liquid discharge head includes a large number of nozzles (discharge ports) for discharging droplets and individual liquid chambers (pressure generation chambers, pressure chambers, pressurized liquid chambers, ink chambers, ink flow paths) through which these nozzles communicate with each other. And an ink-on-demand system that discharges liquid droplets only from nozzles that require recording, and is mainly used. . Such a liquid ejection head boosts the liquid in the individual liquid chamber by driving the ejection driving means, and ejects liquid droplets by pushing out the meniscus liquid that closes the nozzle by the pressure from the nozzle. There are several types of ejection driving means for ejecting droplets. For example, a part of the wall of the individual liquid chamber is configured by a thin diaphragm, a piezoelectric element is disposed on the diaphragm, and a predetermined driving voltage is applied to the piezoelectric element to deform the piezoelectric element to deform the diaphragm. Thus, there is a piezo method in which the pressure in the individual liquid chamber is changed to discharge the droplet. In addition, for example, a heating element is disposed inside the individual liquid chamber, and energizing the heating element to heat the heating element to generate bubbles in the liquid in the individual liquid chamber, thereby boosting the liquid in the individual liquid chamber. Then, a bubble jet (registered trademark) system for discharging droplets can be used. Further, for example, the diaphragm is formed by an electrostatic force generated by applying an electric field between the diaphragm constituting the wall of the individual liquid chamber and the electrode disposed outside the individual liquid chamber so as to face the diaphragm. There has also been proposed an electrostatic method in which the liquid is ejected by changing the pressure in the individual liquid chamber by changing the pressure.

FIG. 8 is a cross-sectional view showing an example of a conventional liquid discharge head.
In the liquid discharge head 300, a nozzle unit 310 in which two or more nozzle rows in which a large number of nozzles (discharge ports) 303a are arranged is arranged in parallel, and a common liquid chamber member 320 having a common liquid chamber B are mutually connected. It has a joined structure. The nozzle unit 310 includes a nozzle substrate 303 on which nozzles 303 a are formed, a flow path plate 301, a vibration plate 302, and the like, and individual liquid chambers A that store liquids supplied to the nozzles 303 a are arranged in the nozzle rows. It is the structure formed along. The common liquid chamber B of the common liquid chamber member 320 is provided for each nozzle row, and each common liquid chamber B communicates with a plurality of individual liquid chambers A arranged along the corresponding nozzle row. In the liquid discharge head 300, the nozzle unit 310 and the common liquid chamber member 320 are joined to each other, whereby the individual liquid chambers A of the nozzle unit 310 and the common liquid chamber B of the common liquid chamber member 320 communicate with each other. The liquid in the common liquid chamber B is configured to be supplied to the individual liquid chamber A.

  Patent Document 1 discloses a liquid discharge head in which the entire common liquid chamber member is produced by resin injection molding. Further, in Patent Document 2, a common liquid chamber member is formed by laminating and joining a plurality of metal plates having substantially the same thickness provided with through holes forming a common liquid chamber so that the through holes overlap each other. A manufactured liquid discharge head is disclosed.

  When the common liquid chamber member is formed of a resin material as in the liquid discharge head disclosed in Patent Document 1, it can be manufactured at a lower cost than that having a metal common liquid chamber member. There are two problems. Hereinafter, a description will be given with reference to FIG.

The first problem is as follows.
Since the liquid discharge head 300 is joined so that the nozzle unit 310 is in close contact with the joint surface of the common liquid chamber member 320, if the flatness of the joint surface of the common liquid chamber member 320 is poor, the nozzle unit 310 is accompanied accordingly. The flatness of the nozzle surface also deteriorates. If the flatness of the nozzle surface is poor, a phenomenon (print misalignment) in which the liquid droplets are displaced from the target landing position on the recording material will occur. In the common liquid chamber member 320 made of a resin material, it is difficult to ensure high flatness with respect to the joint surface. For this reason, there is a problem that printing deviation is likely to occur.

The second problem is as follows.
As shown in FIG. 8, the nozzle unit 310 of the liquid discharge head 300 is obtained by laminating the nozzle unit plate members such as the nozzle substrate 303, the flow path plate 301, and the vibration plate 302 after being finely processed. Can be produced. When a plurality of such nozzle unit plate members 301, 302, and 303 are manufactured from a single sheet material, the number of sheets per sheet material is reduced in order to reduce the processing cost per nozzle unit plate member. It is desired to increase the number of nozzle unit plate members produced by one processing. However, when the common liquid chamber member 320 is made of a resin material as in the liquid discharge head disclosed in Patent Document 1, each of the nozzles is arranged along the nozzle row in order to ensure necessary strength. The wall thickness between the extending common liquid chambers B cannot be reduced. Therefore, the interval between the common liquid chambers B (the distance between the common liquid chambers B in the left-right direction in FIG. 8) cannot be reduced, and as a result, the individual liquid chambers of the nozzle unit 310 respectively communicating with each common liquid chamber B. It is also impossible to reduce the interval between the rows of A. As described above, since the interval between the individual liquid chambers of the nozzle unit cannot be reduced, the size of the nozzle unit 310 in the direction orthogonal to the arrangement direction of the nozzle rows cannot be reduced. Therefore, when a plurality of nozzle unit plate members such as the nozzle substrate 303, the flow path plate 301, and the vibration plate 302 are manufactured from a single sheet material, the number of sheets per sheet material cannot be increased. Since the processing cost per unit plate member cannot be reduced, the manufacturing cost cannot be reduced.
Note that this problem is not limited to nozzle units that are created by laminating nozzle unit plate members, but can also occur when the nozzle unit manufacturing cost can be reduced by reducing the size of the nozzle unit. Is.

  On the other hand, the common liquid chamber member 320 of the liquid discharge head disclosed in Patent Document 2 is made of metal. With such a metal common liquid chamber member, it is possible to ensure a higher flatness with respect to the joint surface with the nozzle unit 310 than with a resin common liquid chamber member. Therefore, the flatness of the nozzle surface of the nozzle unit 310 can be increased, and the occurrence of printing deviation can be suppressed, so that the first problem can be solved. Moreover, if it is a metal common liquid chamber member as disclosed in Patent Document 2, the wall portion between the common liquid chambers B can be made thinner than the resin common liquid chamber member. Therefore, since the size of the nozzle unit 310 in the direction orthogonal to the arrangement direction of the nozzle rows can be reduced and the processing cost per nozzle unit plate member can be reduced, the second problem can be solved. Is possible.

  However, when the common liquid chamber member 320 is formed of a metal material, the manufacturing cost is higher than when the common liquid chamber member 320 is formed of a resin material. For example, when a common liquid chamber is formed by cutting a metal block, the cutting cost is generally higher than when the common liquid chamber is formed by resin molding. Further, for example, when the common liquid chamber member 320 is formed by laminating a plurality of metal plates as in the liquid discharge head disclosed in Patent Document 2, through holes for forming a common liquid chamber are formed in each metal plate. Since the vacant processing can be performed at a low cost by etching, pressing, or the like, the cost for the processing for forming the common liquid chamber can be reduced as compared with the case of cutting the metal block. However, since a process for joining a plurality of metal plates is required, the manufacturing cost is generally higher than when the common liquid chamber is formed by resin molding. In particular, when a plurality of metal plates are diffusion bonded as in the liquid ejection head disclosed in Patent Document 2, the two metal plates heated to a temperature of 1000 ° C. or higher in a vacuum are bonded by pressurization. Since treatment is necessary, the manufacturing cost is particularly high. Therefore, it is desired to solve the above two problems at a lower cost.

  The present invention has been made in view of the above background, and the object of the present invention is to provide a liquid that can suppress the occurrence of printing deviation and reduce the size of the nozzle unit while keeping the manufacturing cost low. It is an object to provide an ejection head and an image forming apparatus including the same.

In order to achieve the above object, according to the first aspect of the present invention, there is provided an individual liquid chamber in which two or more nozzle rows in which a plurality of nozzles are arranged are arranged in parallel and the liquid supplied to each nozzle is stored. Nozzle units arranged along the nozzle rows, a common liquid chamber member provided for each nozzle row with a common liquid chamber communicating with a plurality of individual liquid chambers arranged along the nozzle rows, and each individual liquid chamber Discharge driving means for discharging the liquid in the individual liquid chambers from the corresponding nozzles by boosting the liquid, and the common liquid chamber members corresponding to the inlet openings of the individual liquid chambers of the nozzle unit. In the liquid discharge head configured such that the nozzle unit and the common liquid chamber member are joined so that the outlet opening of the liquid chamber communicates, and the liquid in the common liquid chamber is supplied to the individual liquid chamber. The liquid chamber member is A metal part provided with a through hole that forms a part of each common liquid chamber located on the joining surface side to be joined to the unit, and the other part of each common liquid chamber is formed in communication with the through hole of the metal part The metal part is composed of a metal laminated plate in which three or more metal plates are laminated, and is in a direction orthogonal to the arrangement direction of the nozzle rows. Contact stomach, in which the thickness of the wall of the metal portion between the through hole of the metal portion, characterized in that thinner than the thickness of the wall of the resin portion between the grooves of the resin portion.
The invention of claim 2 is the liquid discharge head according to claim 1, said nozzle unit, a flow for forming a nozzle substrate in which the nozzle row is formed, a liquid flow path including an individual liquid chamber A road plate and a diaphragm that forms at least a part of the wall surface of the individual liquid chamber are laminated and joined, and the discharge driving means drives the diaphragm to remove the liquid in each individual liquid chamber. It is characterized by boosting.
According to a third aspect of the present invention, in the liquid ejection head according to the first or second aspect, at least two of the three or more metal plates have different wall thicknesses of the metal portion between the through holes. A metal plate of a kind is included, and the metal laminate plate includes the three or more sheets so that the thickness of the wall of the metal part between the through holes becomes thinner as the joint surface is joined to the nozzle unit. It is characterized by laminating metal plates.
According to a fourth aspect of the present invention, in the liquid ejection head according to the first or second aspect, the three or more metal plates are positioned on the outermost side in a direction perpendicular to the arrangement direction of the nozzle rows. At least two types of metal plates having different distances between the outer ends of the two through holes are included, and the metal laminate plate is closer to the joint surface to be joined to the nozzle unit. The above-mentioned three or more metal plates are laminated so that the distance between the outer ends is shortened.
The invention of claim 5 is the ejecting droplets to the recording material from the liquid ejecting head image forming apparatus for forming an image on the recording medium, as the liquid discharge head, according to claim 1 to 4 The liquid discharge head described in any one of the items is used.

In the present invention, since the joint surface portion with the nozzle unit in the common liquid chamber member is formed of a metal material, the flatness of the joint surface is higher than that in which this portion is formed of a resin material. Can be obtained. As a result, the flatness of the nozzle surface of the nozzle unit can be increased as compared with the case where the joint surface portion of the common liquid chamber member is formed of a resin material, and the occurrence of printing misalignment can be suppressed.
In addition, in the present invention, only a part of the common liquid chamber member positioned on the bonding surface side to be bonded to the nozzle unit is formed of a metal material that is expensive to process or bond to form the common liquid chamber. The other metal liquid chamber member is a resin portion formed of a resin material. In this way, when the entire common liquid chamber member is formed of a metal material, a part of the resin portion can be processed by low-cost processing such as injection molding to form a common liquid chamber. Compared with, manufacturing cost can be reduced.
Further, since the common liquid chamber member in the present invention is formed of a metal material on the bonding surface side to be bonded to the nozzle unit, the interval between the common liquid chambers (nozzle row of the nozzle row) is larger than that of the resin material. It is possible to reduce the distance between the common liquid chambers in a direction orthogonal to the arrangement direction. Therefore, in the present invention, the wall thickness of the metal part between the through holes of the metal part that forms a part of the joint surface side of each common liquid chamber is set to the resin part that forms the other part of each common liquid chamber. It is made thinner than the wall thickness of the resin part between the grooves. Thereby, the space | interval of the exit opening part of the common liquid chamber opened to a joining surface can be narrowed rather than the case where the whole common liquid chamber member is formed with the resin material. As a result, the row interval of the individual liquid chambers of the nozzle units communicating with the outlet openings of the common liquid chambers can be reduced, so that the size of the nozzle unit in the direction orthogonal to the arrangement direction of the nozzle rows can be reduced. Can do.

  As described above, according to the present invention, the common liquid chamber member is formed at a lower cost than the case where the entire common liquid chamber member is formed of a metal material by forming a part of the common liquid chamber member with a resin material. As in the case where the entirety is formed of a metal material, the excellent effects of suppressing the occurrence of printing deviation and realizing the downsizing of the nozzle unit can be achieved.

It is sectional drawing which cut | disconnected the liquid discharge head in embodiment along the cross section orthogonal to a nozzle row. It is sectional drawing which cut | disconnected the same liquid discharge head along the nozzle row. It is a graph which shows the curvature amount for every board | plate number of the metal laminated board which comprises a metal part. FIG. 10 is a cross-sectional view of the liquid discharge head according to Modification 1 cut along a cross section orthogonal to a nozzle row. FIG. 10 is a cross-sectional view of a liquid ejection head according to Modification 2 cut along a cross section orthogonal to a nozzle row. FIG. 10 is a cross-sectional view of a liquid ejection head according to Modification 3 cut along a cross section orthogonal to a nozzle row. 1 is an explanatory diagram illustrating an inkjet image forming apparatus according to an embodiment. It is sectional drawing which shows an example of the conventional liquid discharge head.

Hereinafter, an embodiment of a liquid discharge head according to the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view of the liquid discharge head 100 according to the present embodiment cut along a cross section orthogonal to the nozzle rows.
FIG. 2 is a cross-sectional view of the liquid ejection head 100 according to the present embodiment cut along a nozzle row.
The liquid discharge head 100 of the present embodiment is mainly composed of a nozzle unit 10, a frame member 20 as a common liquid chamber member, and a piezoelectric element unit 30 as discharge driving means.

  The nozzle unit 10 is formed by laminating a flow path plate 1 for forming a liquid flow path, a vibration plate 2 bonded to the upper surface of the flow path plate 1, and a nozzle substrate 3 bonded to the lower surface of the flow path plate 1. It has been configured. By laminating these plate members, the nozzle unit 10 has a pressurized liquid chamber (a pressure chamber, a pressurized chamber, a flow path) as an individual liquid chamber individually communicating with each nozzle 3 a formed on the nozzle substrate 3. Etc.) A is formed. In the present embodiment, a case where two nozzle rows in which a large number of nozzles are arranged along the longitudinal direction of the liquid discharge head 100 will be described. However, the number of nozzle rows is appropriately set to 2 or more. It is.

  The piezoelectric element unit 30 includes a base member 31 and two piezoelectric element members 32. These piezoelectric element members 32 are provided for each nozzle row and extend along the corresponding nozzle row. One end (upper surface in the drawing) of each piezoelectric element member 32 is held by the base member 31, and the other end (lower surface in the drawing) is bonded to the outer surface of the diaphragm 2 (surface opposite to the pressurized liquid chamber A). It is joined with the agent. One piezoelectric element member 32 has a structure in which a plurality of piezoelectric element columns 32a and 32b are formed without being divided by half-cut groove processing (slit processing). Every other piezoelectric element column 32a is used as a second piezoelectric element column (driving piezoelectric element column) 32a to be driven and a first piezoelectric element column (non-driving piezoelectric element column) 32b to be driven. One end face of each piezoelectric element member 32 is connected to FPC (Flexible Printed Circuits) which is a power supply member for giving a driving waveform.

  The frame member 20 includes two common liquid chambers B communicating with each row of the pressurized liquid chambers A arranged along each nozzle row. The joining surface (the lower surface in the figure) of the frame member 20 is joined to the joined surface of the nozzle unit 10 (the outer surface of the diaphragm 2) with an adhesive, whereby each pressurizing liquid is supplied from the common liquid chamber B of the frame member 20. The chamber A is supplied with ink as a recording liquid that is a liquid.

  The frame member 20 in this embodiment includes a metal part 21 and a resin part 22. A common liquid chamber B serving as a flow path for ink supplied to each pressurized liquid chamber A has through holes B1, B2, B3, B4 formed in the metal portion 21 and a groove B5 formed in the resin portion 22. And formed by.

  In the present embodiment, the inlet opening 3b of each pressurized liquid chamber A opened on the surface to be joined of the nozzle unit 10 and the outlet opening (penetration) of the common liquid chamber B opened on the joint surface of the frame member 20 are used. By communicating with the hole B 1), ink conveyed from an ink cartridge (not shown) is supplied to each pressurized liquid chamber A through the common liquid chamber B in the frame member 20. As shown in FIG. 1, the frame member 20 of the present embodiment has an interval between the two through holes B <b> 1 in the metal part 21 constituting the outlet opening part of the two common liquid chambers. It is narrower than the interval. In other words, the end of the through hole B1 of the metal part 21 on the side of the piezoelectric element member 32 is located on the side of the piezoelectric element member 32, that is, the inside of the head, relative to the end of the groove B5 of the resin part 22 on the side of the piezoelectric element member 32. .

  Moreover, the metal part 21 is comprised with the metal laminated plate which laminated | stacked the several metal plate, and becomes the structure which adhere | attached and laminated | stacked the four metal plates 21a, 21b, 21c, and 21d in this embodiment. As shown in FIG. 1, each of the through holes B1, B2, B3, and B4 formed in the four metal plates 21a, 21b, 21c, and 21d in the present embodiment is perpendicular to the nozzle row (hereinafter, “ In the "head width direction"), the dimensions are the same, but the positions where the through holes are provided are different from each other. Specifically, the closer to the joining surface to be joined to the nozzle unit 10 (that is, the lower it is in the drawing), the spacing between the two through holes formed in each of the metal plates 21a, 21b, 21c, and 21d. The through holes B1, B2, B3, B4 of the respective metal plates are formed so as to be narrow. Thereby, the wall surface of the common liquid chamber part in the metal part 21 has a stepped shape and is gradually displaced toward the inside of the head. As a result, the ink in the common liquid chamber portion of the metal portion 21 can be smoothly fed into the pressurized liquid chamber A of the nozzle unit 10.

  When the metal part 21 of the frame member 20 is configured with a metal laminated plate as in the present embodiment, in the metal plate used in the present embodiment, when the metal part 21 is configured with a metal laminated plate composed of two metal plates, As shown in the graph of FIG. 3, warpage occurs in the metal laminate, and even if the joining surface side of the frame member 20 is configured by the metal portion 21, the flatness of the joining surface cannot be increased. Therefore, the flatness of the nozzle surface of the nozzle unit 10 (the outer surface of the nozzle substrate 3) cannot be increased, and printing misalignment is likely to occur. On the other hand, if the metal part 21 is composed of a metal laminated plate composed of three or more metal plates, warpage of the metal laminated plate can be sufficiently suppressed as shown in the graph of FIG. 3, and the joint surface of the frame member 20 is high. Flatness can be obtained.

  Here, if the entire frame member is formed of a resin material, the interval between the outlet openings of the common liquid chamber corresponds to the interval between the outlet openings (grooves B5) of the resin portion 22 shown in FIG. To be. On the other hand, in this embodiment, the space | interval (namely, space | interval between through-hole B1) between the exit openings of a common liquid chamber becomes smaller than the case where the whole frame member is formed with a resin material. Therefore, the inlet opening of the pressurized liquid chamber A of the nozzle unit 10 communicating with the outlet opening of the common liquid chamber can be positioned more inside the head. As a result, the size of the nozzle unit 10 in the head width direction can be made smaller. Accordingly, the dimensions of the various plate members 1, 2, and 3 constituting the nozzle unit 10 are reduced, the number of sheets per sheet material is increased, and the various plate members 1, 2, and 3 manufactured by one processing are reduced. The number can be increased, and the processing cost per plate member can be reduced. In addition, the material of the various plate members 1, 2, and 3 constituting the nozzle unit 10 can be made of a metal such as stainless steel or nickel, a resin such as a polyimide resin film, silicon, or a combination thereof. In order to ensure liquid repellency with the ink, it is preferable to form a liquid repellent film on the nozzle surface by a known method such as a plating film or a liquid repellent coating.

Next, the operation of the liquid ejection head 100 in this embodiment will be described.
In the liquid ejection head 100 according to the present embodiment, for example, the voltage applied to the second piezoelectric element column 32a of the piezoelectric element unit 30 is lowered from the reference potential, whereby the second piezoelectric element column 32a contracts and the diaphragm 2 The corresponding portion can be lowered and the volume of the pressurized liquid chamber A can be expanded. As a result, the ink in the common liquid chamber B flows into the corresponding pressurized liquid chamber A. After that, when the voltage applied to the second piezoelectric element column 32a is increased to extend the second piezoelectric element column 32a in the stacking direction, the corresponding portion of the diaphragm 2 is displaced in the nozzle direction, and the pressurized liquid chamber A The volume of can be shrunk. As a result, the pressure in the pressurized liquid chamber A is increased, and ink droplets are ejected (ejected) from the nozzle 3 a communicating with the pressurized liquid chamber A. Then, by returning the voltage applied to the second piezoelectric element column 32a to the reference potential, the corresponding portion of the diaphragm 2 is restored to the initial position, whereby the pressurized liquid chamber A expands and negative pressure is generated. . At this time, the pressurized liquid chamber A is filled with ink from the common liquid chamber B, and after the vibration of the meniscus surface of the nozzle is attenuated and stabilized, the operation proceeds to the operation for discharging the next ink droplet.

  As described above, according to the present embodiment, a part of the frame member 20 located on the joining surface side of the frame member 20 joined to the nozzle unit 10 is configured by the metal part 21, and the other part is the resin part 22. Since they are formed and joined to each other, the manufacturing cost can be reduced as compared with the case where the entire frame member 20 is formed of a metal material. Moreover, since the joint surface portion with the nozzle unit 10 in the frame member 20 is formed of a metal material, it is possible to obtain a higher flatness with respect to the joint surface than that in which this portion is formed of a resin material. In addition, the occurrence of printing deviation is suppressed as in the case where the entire frame member 20 is formed of a metal material. Moreover, since the flatness of the joining surface is ensured by forming the joining surface side of the frame member 20 with a metal material in this way, it is not necessary to provide a flatness accuracy in the resin molding of the resin portion 22, and as a result, the resin portion A lower cost resin material can be used as the material 22.

  Furthermore, since the frame member 20 in this embodiment is formed of a metal material on the bonding surface side to be bonded to the nozzle unit 10, the distance between the two common liquid chambers B is larger than that of a resin material. (Distance between two common liquid chambers B in the head width direction) can be reduced. Thereby, the space | interval between the exit opening parts of the common liquid chamber B can be narrowed rather than the case where the whole frame member 20 is formed with the resin material. As a result, since the interval between the inlet openings of the individual liquid chambers of the nozzle unit 10 communicating with the outlet openings of the two common liquid chambers can be reduced, the size of the nozzle unit 10 in the head width direction can be reduced. Can do. As a result, the number of sheets per sheet material for the various plate members 1, 2 and 3 constituting the nozzle unit 10 is increased, and the number of various plate members 1, 2 and 3 produced by one processing is increased. Therefore, the processing cost per plate member can be reduced.

[Modification 1]
Next, a modification of the liquid ejection head in the above embodiment (hereinafter, this modification is referred to as “modification 1”) will be described.
FIG. 4 is a cross-sectional view of the liquid ejection head 100 according to Modification 1 cut along a cross section orthogonal to the nozzle rows.
As for the frame member 20 in this modification 1, the metal part 21 is comprised with the metal laminated board which consists of four metal plates similarly to the said embodiment. However, the four metal plates include two types of metal plates having different distances between the outer ends of the two through holes in the head width direction. Specifically, the distance between the outer ends of the two through holes in the other metal plates 21a, 21b, and 21c is larger than the distance between the outer ends of the two through holes in the fourth metal plate 21d joined to the resin portion 22. The distance is shorter. In the first modification, the distance between the inner ends of the two through holes is the same for all the metal plates, but may be different.

  Also in the first modification, the size of the nozzle unit 10 in the head width direction can be reduced similarly to the above embodiment, so that the processing costs of the various plate members 1, 2, and 3 constituting the nozzle unit 10 are reduced. it can.

[Modification 2]
Next, another modified example of the liquid ejection head in the above embodiment (hereinafter, this modified example is referred to as “modified example 2”) will be described.
FIG. 5 is a cross-sectional view of the liquid discharge head 100 according to Modification 2 cut along a cross section orthogonal to the nozzle rows.
In the frame member 20 in the second modification, the metal portion 21 is composed of a metal laminated plate made of four metal plates, as in the above embodiment, but each of the metal plates 21a, 21b, 21c, 21d. The two through holes in are both formed in the same size and at the same position. However, the interval between the two through holes B1, B2, B3, B4 in each metal plate 21a, 21b, 21c, 21d is narrower than the interval between the grooves B5 of the resin part.

Also in the second modification, since the dimensions of the nozzle unit 10 in the head width direction can be reduced as in the above embodiment, the processing costs of the various plate members 1, 2, and 3 constituting the nozzle unit 10 are reduced. it can.
In addition, according to the second modification, the metal part 21 is configured by laminating a single type of metal plate, so that the metal part 21 is configured by laminating a plurality of types of metal plates. It is possible to reduce the manufacturing cost.

[Modification 3]
Next, still another modified example (hereinafter, this modified example is referred to as “modified example 3”) of the liquid ejection head in the above embodiment will be described.
FIG. 6 is a cross-sectional view of the liquid ejection head 100 according to Modification 3 cut along a cross section orthogonal to the nozzle row.
The frame member 20 in the third modification is configured by a metal block whose metal part 21 has a through hole B6. However, the interval between the two through holes B6 formed in the metal block is narrower than the interval between the grooves B5 of the resin portion.

  Also in the third modification, as in the above embodiment, the size of the nozzle unit 10 in the head width direction can be reduced, so that the processing costs of the various plate members 1, 2, and 3 constituting the nozzle unit 10 are reduced. it can.

Next, an example in which the liquid discharge head 100 according to the present embodiment is used as a recording head of an inkjet image forming apparatus will be described.
FIG. 7 is an explanatory diagram illustrating an inkjet image forming apparatus according to the present embodiment.
This image forming apparatus is a line type image forming apparatus, has an image forming unit 202 and the like inside the apparatus main body 201, and can supply a large number of recording materials (paper sheets) 203 on the lower side of the apparatus main body 201. A paper tray 204 is provided, the paper 203 fed from the paper feed tray 204 is taken in, a required image is recorded by the image forming unit 202 while the paper 203 is being transported by the transport mechanism 205, and then the side of the apparatus main body 201. The paper 203 is discharged to a paper discharge tray 206 attached to the printer.

  In addition, a duplex unit 207 that can be attached to and detached from the apparatus main body 201 is provided, and when performing duplex printing, the sheet 203 is taken into the duplex unit 207 while being transported in the reverse direction by the transport mechanism 205 after one-side (front) printing is completed. Then, the other side (back side) is sent to the transport mechanism 205 again as the printable side, and the sheet 203 is discharged to the discharge tray 206 after the other side (back side) printing is completed.

  Here, the image forming unit 202, for example, four full-line liquid ejection heads 100 that eject ink droplets of each color of black (k), cyan (c), magenta (m), and yellow (y). Recording heads 211k, 211c, 211m, and 211y (referred to as “recording head 211” when colors are not distinguished), and each recording head 211 has a nozzle surface on which nozzles for discharging droplets are directed downward. It is attached to the head holder 213. Further, maintenance recovery mechanisms 212k, 212c, 212m, and 212y for maintaining and recovering the head performance corresponding to each recording head 211 (referred to as “maintenance recovery mechanism 212” when colors are not distinguished) are provided, purge processing, During the head performance maintenance operation such as wiping processing, the recording head 211 and the maintenance / recovery mechanism 212 are relatively moved so that the capping member constituting the maintenance / recovery mechanism 212 faces the nozzle surface of the recording head 211.

  Here, the recording head 211 is arranged to eject ink droplets of each color in the order of yellow, magenta, cyan, and black from the upstream side in the paper conveyance direction, but the arrangement and the number of colors are not limited to this. . Further, as the line-type head, one or a plurality of heads provided with a plurality of nozzle rows for discharging ink droplets of each color at a predetermined interval can be used, and a recording liquid for supplying a recording liquid to the head and the head. The cartridge can be integrated or separated.

  The sheets 203 in the sheet feeding tray 204 are separated one by one by a sheet feeding roller (half-moon roller) 221 and a separation pad (not shown) and fed into the apparatus main body 201, and are registered along the guide surface 223 a of the conveyance guide member 223. 225 and the conveying belt 233, and are sent to the conveying belt 233 of the conveying mechanism 205 via the guide member 226 at a predetermined timing. In addition, a guide surface 223 b that guides the sheet 203 sent out from the duplex unit 207 is also formed on the transport guide member 223. Further, a guide member 227 for guiding the sheet 203 returned from the transport mechanism 205 during duplex printing to the duplex unit 207 is also provided.

  The transport mechanism 205 includes an endless transport belt 233 that is stretched between a transport roller 231 that is a driving roller and a driven roller 232, a charging roller 234 that charges the transport belt 233, and an image forming unit 202. A platen member 235 that maintains the flatness of the conveying belt 233 at the opposite portion, a pressing roller 236 that presses the paper 203 fed from the conveying belt 233 against the conveying roller 231, and other recording liquid that is not shown, but adheres to the conveying belt 233. It has a cleaning roller made of a porous material or the like, which is a cleaning means for removing (ink). A paper discharge roller 238 and a spur 239 for sending the paper 203 on which an image is recorded to the paper discharge tray 206 are provided on the downstream side of the transport mechanism 205.

  In the image forming apparatus configured as described above, the conveying belt 233 rotates in the direction indicated by the arrow, and is charged to positive polarity by coming into contact with the charging roller 234 to which a high potential applied voltage is applied. In this case, the charging belt 233 is charged at a predetermined charging pitch by switching the polarity of the charging voltage of the charging roller 234 at a predetermined time interval. Here, when the sheet 203 is fed onto the conveying belt 233 charged to this high potential, the inside of the sheet 203 is in a polarized state, and the charge opposite in polarity to the charge on the conveying belt 233 is conveyed to the conveying belt 233 of the sheet 203. The charge on the transport belt 233 and the charge on the transported sheet 203 are electrostatically attracted to each other, and the sheet 203 is electrostatically attracted to the transport belt 233. Is done. In this way, the sheet 203 strongly adsorbed to the conveyor belt 233 is calibrated for warpage and unevenness, and a highly flat surface is formed. Then, the paper 203 is moved around the conveyor belt 233 and droplets are ejected from the recording head 211, whereby a required image is formed on the paper 203, and the paper 203 on which the image is recorded is discharged to the paper discharge roller 238. Is discharged to the discharge tray 206.

Since the image forming apparatus includes the recording head 211 including the liquid discharge head 100 described above, an image can be formed at high speed using a recording head that can obtain high reliability.
In this embodiment, the liquid ejection head 100 according to the present invention is described as an example applied to an image forming apparatus having a printer configuration. However, the present invention is not limited to this. For example, an image of a printer / fax / copier multifunction machine or the like is used. It can be applied to a forming apparatus. Also, the present invention can be applied to an image forming apparatus using a liquid other than the narrowly defined ink or a fixing processing liquid, or an apparatus other than the image forming apparatus.

As described above, the liquid ejection head 100 according to the present embodiment stores two or more nozzle rows in which a plurality of nozzles 3a are arranged in parallel, and stores ink that is liquid supplied to each nozzle 3a. A nozzle unit 10 in which pressurized liquid chambers A as individual liquid chambers are arranged along the nozzle rows, and a common liquid chamber B communicating with the plurality of pressurized liquid chambers A arranged along the nozzle rows for each nozzle row. And a piezoelectric element as discharge driving means for discharging the liquid in the pressurized liquid chamber A from the corresponding nozzle by boosting the liquid in each pressurized liquid chamber A. The nozzle unit 10 and the frame member so that the inlet opening of each pressurized liquid chamber A of the nozzle unit 10 communicates with the outlet opening of the common liquid chamber B of the frame member 20 corresponding thereto. 20 and Combined, the liquid inside the common liquid chamber B is configured to be supplied to the pressurized liquid chamber A. In this liquid ejection head 100, the frame member 20 includes through holes B1, B2, B3, B4, and B6 that are located on the side of the joint surface that is joined to the nozzle unit 10 and that form a part of each common liquid chamber B. The metal part 21 is joined to the resin part 22 provided with a groove B5 that communicates with the through hole of the metal part 21 and forms the other part of each common liquid chamber B. The interval between the through holes of the metal part 21 in the direction orthogonal to the arrangement direction of the nozzle rows (head width direction) is narrower than the interval between the grooves of the resin part 22. Therefore, as described above, the manufacturing cost can be reduced as compared with the case where the entire frame member 20 is formed of a metal material. Moreover, compared to the case where the joint surface portion of the frame member 20 with the nozzle unit 10 is formed of a resin material, the flatness of the joint surface can be obtained, and the entire frame member 20 is formed of a metal material. As in the case of performing printing, the occurrence of printing deviation is suppressed. Furthermore, the interval between the outlet openings of the common liquid chamber B can be narrowed and the size of the nozzle unit 10 in the head width direction can be made smaller than when the entire frame member 20 is formed of a resin material. Therefore, the processing cost of the various plate members 1, 2, 3 constituting the nozzle unit 10 can be reduced.
In the present embodiment, the nozzle unit 10 includes a nozzle substrate 3 on which nozzle rows are formed, a flow path plate 1 for forming a liquid flow path including the pressurized liquid chamber A, and a pressurized liquid chamber A. The piezoelectric element unit 30 pressurizes the ink in each pressurized liquid chamber A by driving the diaphragm 2. Thereby, the nozzle unit 10 can be manufactured at lower cost.
Further, in the present embodiment (excluding Modification 3), the metal portion 21 of the frame member 20 is composed of a metal laminated plate in which three or more metal plates 21a, 21b, 21c, and 21d are laminated. The metal part 21 can be manufactured at lower cost.
Further, in the present embodiment (except for the modifications 2 and 3), the three or more metal plates 21a, 21b, 21c, and 21d include at least two types of metal plates having different intervals between the through holes. The metal laminated plate constituting the metal portion 21 is obtained by laminating three or more metal plates so that the interval between the through holes becomes narrower as the joint surface to be joined to the nozzle unit 10 is closer. It is. As a result, the wall surface of the common liquid chamber portion in the metal portion 21 has a stepped shape and is gradually displaced toward the inside of the head, so that the ink in the common liquid chamber portion of the metal portion 21 is smoothly added to the nozzle unit 10. It can be fed into the pressure chamber A.
Further, in the present embodiment (excluding Modification 3), the three or more metal plates 21a, 21b, 21c, and 21d are provided between the outer ends of the two through holes positioned at the outermost measurement in the head width direction. At least two types of metal plates with different distances are included, and the metal laminated plate constituting the metal portion 21 is closer to the joint surface joined to the nozzle unit 10 and between the outer ends of the two through holes. The three or more metal plates are laminated so that the distance between them becomes shorter. As a result, the wall surface of the common liquid chamber portion in the metal portion 21 has a stepped shape and is gradually displaced toward the inside of the head, so that the ink in the common liquid chamber portion of the metal portion 21 is smoothly added to the nozzle unit 10. It can be fed into the pressure chamber A.

1,301 Channel plate 2,302 Vibration plate 3,303 Nozzle substrate 3a, 303a Nozzle 10, 310 Nozzle unit 20 Frame member 21a, 21b, 21c, 21d Metal plate 21 Metal portion 22 Resin portion 30 Piezoelectric element unit 31 Base member 32 Piezoelectric element member 100, 300 Liquid discharge head 211k, 211c, 211m, 211y Recording head 320 Common liquid chamber member A Pressure liquid chamber B Common liquid chamber

JP 2007-144706 A JP 2007-216633 A

Claims (5)

A nozzle unit in which two or more nozzle rows in which a plurality of nozzles are arranged are arranged in parallel, and individual liquid chambers for storing liquid supplied to each nozzle are arranged along the nozzle rows;
A common liquid chamber member provided for each nozzle row with a common liquid chamber communicating with a plurality of individual liquid chambers arranged along the nozzle row;
Discharge driving means for discharging the liquid in the individual liquid chambers from the corresponding nozzles by boosting the liquid in each individual liquid chamber;
The nozzle unit and the common liquid chamber member are joined so that the inlet opening of each individual liquid chamber of the nozzle unit communicates with the outlet opening of the common liquid chamber of the common liquid chamber member corresponding thereto. In the liquid discharge head configured to supply the liquid in the common liquid chamber to the individual liquid chamber,
The common liquid chamber member communicates with a metal part having a through hole that is located on a joining surface side to be joined to the nozzle unit and forms a part of each common liquid chamber, and the through hole of the metal part. The resin part provided with a groove that forms the other part of each common liquid chamber is joined,
The metal part is composed of a metal laminate in which three or more metal plates are laminated,
And have you in the direction orthogonal to the array direction of the nozzle array, the thickness of the wall of the metal portion between the through hole of the metal portion is thinner than the thickness of the wall of the resin portion between the grooves of the resin portion A liquid discharge head. The liquid discharge head according to claim 1,
The nozzle unit includes a nozzle substrate on which the nozzle row is formed, a flow path plate for forming a liquid flow path including an individual liquid chamber, and a vibration plate that forms at least a part of a wall surface of the individual liquid chamber. Are laminated and joined,
The liquid ejection head, wherein the ejection driving means boosts the liquid in each individual liquid chamber by driving the diaphragm. The liquid discharge head according to claim 1 or 2 ,
The three or more metal plates include at least two types of metal plates having different wall thicknesses of the metal part between the through holes,
The metal laminated plate is obtained by laminating the three or more metal plates so that the thickness of the wall of the metal part between the through holes becomes thinner as the joint surface to be joined to the nozzle unit is closer. A liquid discharge head characterized by the above. The liquid discharge head according to claim 1 or 2 ,
The three or more metal plates include at least two types of metal plates having different distances between the outer ends of the two through holes located at the outermost measurement in the direction orthogonal to the arrangement direction of the nozzle rows. And
The metal laminate plate is obtained by laminating the three or more metal plates so that the distance between the outer ends of the two through holes becomes shorter as the joint surface joined to the nozzle unit is closer. A liquid discharge head. In an image forming apparatus for forming an image on a recording material by ejecting droplets from the liquid ejection head to the recording material,
As the liquid ejecting head, an image forming apparatus characterized by using a liquid discharge head according to any one of claims 1 to 4.

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