JP2006305911A - Liquid delivery head and method for manufacturing liquid delivery head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve a degree of freedom of wiring for electric system by preventing the unevenness of impact position of droplets delivered from a nozzle while enabling the nozzle arrangement with high density to be obtained. <P>SOLUTION: The head is composed by stacking in the 1st direction a plurality of pressure chamber units which have, at least, nozzles for delivering a liquid, pressure chambers for filling the liquid, supply ports for feeding the liquid to the pressure chambers and piezoelectric elements for displacing the wall surface of the pressure chambers. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a liquid discharge head, and more particularly, to a liquid discharge head in which nozzles for discharging ink droplets are arranged with high density.

  An ink jet recording apparatus (ink jet printer) includes a print head (liquid ejection head) having a large number of nozzles, and uses the displacement of the piezoelectric element while moving the print head and the recording medium relatively to each other. In some cases, an image is formed on a recording medium by ejecting ink filled in a pressure chamber as ink droplets from a nozzle.

  Incidentally, a matrix type print head in which nozzles are arranged in a two-dimensional form (matrix form) has been conventionally known in order to achieve high image quality (high density printing). In this print head, projection nozzle rows projected so as to be arranged in a direction (main scanning direction) substantially orthogonal to the relative conveyance direction (sub-scanning direction) of the recording medium are arranged with high density.

  For example, Patent Document 1 describes a print head in which a plurality of thin plate members are stacked, and a nozzle is two-dimensionally arranged on one plate member (nozzle plate) that forms a surface perpendicular to the stacking direction. In other plate members (base plates), pressure chambers corresponding to the nozzles are two-dimensionally arranged.

Patent Document 2 and Patent Document 3 describe a print head in which nozzles are two-dimensionally arranged on a plane parallel to the stacking direction of thin plate members. This print head has a structure in which a plurality of flow path substrates and diaphragms are alternately stacked, and each flow path substrate has slit-shaped flow path holes corresponding to pressure chambers arranged in a row, and Nozzles corresponding to the passage holes are formed on the side surfaces of each passage substrate.
JP 2002-166543 A Japanese Unexamined Patent Publication No. 7-323541 JP 7-323544 A

  By the way, in the print head using the displacement of the piezoelectric element, it is necessary to ensure the size of the pressure chamber more than a predetermined size in order to obtain a sufficient volume change of the pressure chamber with respect to the drive voltage applied to the drive electrode of the piezoelectric element. . In the print head described in Patent Document 1, since the nozzles and the pressure chambers are two-dimensionally arranged as described above, the inter-nozzle pitch of the projected nozzle rows projected so as to be aligned in the main scanning direction is set. When shrinking, the size of the print head in the sub-scanning direction increases. In this case, since the area of the ink discharge surface facing the recording medium of the print head is increased, the accuracy of the distance (height) between the ink discharge surface of the print head and the recording medium is deteriorated, and recording is performed from each nozzle. There is a problem in that the landing positions of the ink droplets ejected on the medium vary. In addition, since the drive electrodes corresponding to the respective pressure chambers are also two-dimensionally arranged, there is a fear that an electric wiring space for connecting each drive electrode to the drive circuit is insufficient.

  In addition, the print heads disclosed in Patent Document 2 and Patent Document 3 have slit-shaped channel holes communicating with the respective nozzles arranged in a row on each channel substrate. It is difficult to reduce the inter-nozzle pitch of the arranged nozzle rows. Therefore, in order to arrange the nozzles with high density, it is necessary to increase the number of laminated flow path substrates and diaphragms. As a result, the size of the print head in the stacking direction (sub-scanning direction) increases, and there is a problem in that the landing positions of ink droplets ejected from the nozzles vary. Further, the direction in which the drive electrode of the piezoelectric element is drawn out is limited to one direction, and there is a fear that the electric wiring space for connecting each drive electrode to the drive circuit is insufficient.

  The present invention has been made in view of such circumstances, and it is possible to realize a high-density arrangement of nozzles, prevent variations in landing positions of liquid droplets discharged from the nozzles, and increase the degree of freedom of wiring in the electrical system. An object of the present invention is to provide an improved liquid discharge head and a method of manufacturing the liquid discharge head.

  In order to achieve the above object, the invention according to claim 1 includes at least a nozzle for discharging liquid, a pressure chamber for filling the liquid, a supply port for supplying the liquid to the pressure chamber, and a pressure chamber. Provided is a liquid discharge head comprising a plurality of pressure chamber units each having a piezoelectric element for displacing a wall surface in a first direction.

  According to the present invention, by stacking a plurality of pressure chamber units having nozzles, pressure chambers, supply ports, and piezoelectric elements in the first direction, the nozzles can be arranged in a high density in the first direction. At the same time, variations in the landing positions of the droplets ejected from the nozzles are prevented, and the degree of freedom of wiring in the electrical system is improved.

  When the liquid discharge head is configured as a full-line head, the main scanning direction, which is a direction substantially perpendicular to the relative conveyance direction of the recording medium with respect to the head, is the first direction, and is the relative conveyance direction of the recording medium with respect to the head. The sub-scanning direction is the second direction.

  When the liquid discharge head is configured as a serial type head, the main scanning direction that is the scanning direction of the head (the width direction of the recording medium) is the second direction, and the sub-direction that is the relative conveyance direction of the recording medium with respect to the head. The scanning direction is the first direction.

  A second aspect of the present invention is the liquid ejection head according to the first aspect, wherein a plurality of the substantially thin plate-like piezoelectric elements are arranged in the thickness direction of the piezoelectric element corresponding to the first direction. It is characterized by being.

  According to the aspect of claim 2, it is possible to arrange the nozzles in the first direction at a higher density.

  A third aspect of the present invention is the liquid discharge head according to the first or second aspect, wherein the pressure chamber unit is configured by laminating a plurality of ceramic green sheets in the first direction. It is characterized by that.

  The pressure chamber unit is preferably a laminated body in which a plurality of ceramic green sheets are laminated in the first direction.

  A fourth aspect of the present invention is the liquid discharge head according to any one of the first to third aspects, wherein the nozzles are arranged one-dimensionally in the first direction. It is characterized by.

  According to the fourth aspect of the present invention, the nozzle arrangement direction and the plane direction of the piezoelectric element are orthogonal to each other, and the area space of the plane of the piezoelectric element and the nozzle pitch are independent from each other. Can be arranged in a one-dimensional and high-density manner.

  According to a fifth aspect of the invention, in the liquid ejection head according to any one of the first to third aspects, the nozzles adjacent to each other in the projection nozzle row projected so as to be aligned in the first direction. The positions in the second direction substantially orthogonal to the first direction are different from each other.

  According to the aspect of the fifth aspect, it is possible to prevent crosstalk between adjacent nozzles in the projection nozzle row projected so as to be aligned in the first direction.

  According to a sixth aspect of the invention, in the liquid ejection head according to the fifth aspect, the pitch between dots in the second direction formed on the recording medium is Pd, n is a positive integer, and 0 <k. When <1, the second nozzle adjacent to the first nozzle in the projection nozzle row is arranged so as to be shifted by (n + k) × Pd in the second direction with respect to the first nozzle. And

  According to the aspect of the sixth aspect, adjacent nozzles in the projection nozzle row projected so as to be aligned in the first direction do not discharge ink at the same drive timing, and crosstalk between these nozzles is more sure. Can be prevented.

  A seventh aspect of the present invention is the liquid ejection head according to any one of the first to sixth aspects, wherein the first direction is a relative conveyance direction of the recording medium with respect to the liquid ejection head. And the second direction is a sub-scanning direction that is a relative conveyance direction of the recording medium with respect to the liquid ejection head.

  The invention according to claim 8 includes at least a nozzle for discharging liquid, a pressure chamber for filling the liquid, a supply port for supplying the liquid to the pressure chamber, and a piezoelectric element for displacing the wall surface of the pressure chamber. A method of manufacturing a liquid discharge head constituted by laminating a plurality of laminated ceramic green sheets in a first direction, and filling a binder resin into a hole or a groove corresponding to the pressure chamber There is provided a method for manufacturing a liquid discharge head, comprising: a step; and a step of debinding and baking after the laminated body is laminated in the first direction.

  A ninth aspect of the present invention is the method of manufacturing a liquid discharge head according to the eighth aspect, wherein the first direction is a main scanning direction substantially orthogonal to the relative conveyance direction of the recording medium with respect to the liquid discharge head. It is characterized by being.

  According to the present invention, by stacking a plurality of pressure chamber units having nozzles, pressure chambers, supply ports, and piezoelectric elements in the first direction, the nozzles can be arranged in a high density in the first direction. At the same time, variations in the landing positions of the droplets ejected from the nozzles are prevented, and the degree of freedom of wiring in the electrical system is improved.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[First Embodiment: Overall Configuration of Inkjet Recording Apparatus]
FIG. 1 is an overall schematic diagram of an ink jet recording apparatus including a print head (liquid ejection head) according to a first embodiment of the present invention. As shown in FIG. 1, the inkjet recording apparatus 10 includes a printing unit 12 having a plurality of printing heads 12K, 12C, 12M, and 12Y provided for each ink color, and each printing head 12K, 12C, 12M, and 12Y. An ink storage / loading unit 14 for storing ink to be supplied to the paper, a paper feeding unit 18 for supplying the recording paper 16, a decurling unit 20 for removing curling of the recording paper 16, and a nozzle surface of the printing unit 12 An adsorption belt conveyance unit 22 that is arranged opposite to the (ink ejection surface) and conveys the recording paper 16 while maintaining the flatness of the recording paper 16, a print detection unit 24 that reads a printing result by the printing unit 12, and a print And a paper discharge unit 26 for discharging the printed recording paper (printed matter) to the outside.

  In FIG. 1, a magazine for rolled paper (continuous paper) is shown as an example of the paper supply unit 18, but a plurality of magazines having different paper widths, paper quality, and the like may be provided side by side. Further, instead of the roll paper magazine or in combination therewith, the paper may be supplied by a cassette in which cut papers are stacked and loaded.

  In the case of an apparatus configuration using roll paper, a cutter 28 is provided as shown in FIG. 1, and the roll paper is cut into a desired size by the cutter 28. The cutter 28 includes a fixed blade 28A having a length equal to or greater than the conveyance path width of the recording paper 16, and a round blade 28B that moves along the fixed blade 28A. The fixed blade 28A is provided on the back side of the print. The round blade 28B is arranged on the print surface side with the conveyance path interposed therebetween. Note that the cutter 28 is not necessary when cut paper is used.

  When multiple types of recording paper are used, an information recording body such as a barcode or wireless tag that records paper type information is attached to the magazine, and the information on the information recording body is read by a predetermined reader. Therefore, it is preferable to automatically determine the type of paper to be used and perform ink ejection control so as to realize appropriate ink ejection according to the type of paper.

  The recording paper 16 delivered from the paper supply unit 18 retains curl due to having been loaded in the magazine. In order to remove this curl, heat is applied to the recording paper 16 by the heating drum 30 in the direction opposite to the curl direction of the magazine in the decurling unit 20. At this time, it is more preferable to control the heating temperature so that the printed surface is slightly curled outward.

  After the decurling process, the cut recording paper 16 is sent to the suction belt conveyance unit 22. The suction belt conveyance unit 22 has a structure in which an endless belt 33 is wound between rollers 31 and 32, and at least a portion facing the nozzle surface of the printing unit 12 and the sensor surface of the printing detection unit 24 is flat ( Flat surface).

  The belt 33 has a width that is greater than the width of the recording paper 16, and a plurality of suction holes (not shown) are formed on the belt surface. As shown in FIG. 1, an adsorption chamber 34 is provided at a position facing the nozzle surface of the print unit 12 and the sensor surface of the print detection unit 24 inside the belt 33 spanned between the rollers 31 and 32. Then, the suction chamber 34 is sucked by the fan 35 to be a negative pressure, whereby the recording paper 16 on the belt 33 is sucked and held.

  The power of a motor (not shown) is transmitted to at least one of the rollers 31 and 32 around which the belt 33 is wound, so that the belt 33 is driven in the clockwise direction in FIG. The recording paper 16 is conveyed from left to right in FIG.

  Since ink adheres to the belt 33 when a borderless print or the like is printed, the belt cleaning unit 36 is provided at a predetermined position outside the belt 33 (an appropriate position other than the print area). Although details of the configuration of the belt cleaning unit 36 are not shown, for example, there are a method of niping a brush roll, a water absorbing roll, etc., an air blowing method of spraying clean air, or a combination thereof. In the case where the cleaning roll is nipped, the cleaning effect is great if the belt linear velocity and the roller linear velocity are changed.

  Although a mode using a roller / nip transport mechanism instead of the suction belt transport unit 22 is also conceivable, when the print area is transported by a roller / nip, the roller comes into contact with the print surface of the paper immediately after printing, so that the image blurs. There is a problem that it is easy. Therefore, as in this example, suction belt conveyance that does not contact the image surface in the printing region is preferable.

  A heating fan 40 is provided on the upstream side of the printing unit 12 on the paper conveyance path formed by the suction belt conveyance unit 22. The heating fan 40 heats the recording paper 16 by blowing heated air onto the recording paper 16 before printing. Heating the recording paper 16 immediately before printing makes it easier for the ink to dry after landing.

  The printing unit 12 is a so-called full-line type head in which line-type heads having a length corresponding to the maximum paper width are arranged in a direction (main scanning direction) orthogonal to the paper transport direction (sub-scanning direction) ( (See FIG. 2). Although a detailed structural example will be described later (see FIGS. 3 to 6), each of the print heads 12K, 12C, 12M, and 12Y constituting the printing unit 12 is intended for the inkjet recording apparatus 10 as shown in FIG. The line-type head in which ink ejection ports (nozzles) are arranged in a line over a length exceeding at least one side of the maximum size recording paper 16 is configured.

  Printing corresponding to each color ink in the order of black (K), cyan (C), magenta (M), and yellow (Y) from the upstream side (left side in FIG. 1) along the conveyance direction (paper conveyance direction) of the recording paper 16 Heads 12K, 12C, 12M, and 12Y are arranged. A color image can be formed on the recording paper 16 by discharging the color inks from the print heads 12K, 12C, 12M, and 12Y while the recording paper 16 is conveyed.

  As described above, according to the printing unit 12 in which the full line head covering the entire area of the paper width is provided for each ink color, the recording paper 16 and the printing unit 12 are relatively moved in the paper transport direction (sub-scanning direction). It is possible to record an image on the entire surface of the recording paper 16 by performing the operation once (that is, by one sub-scanning). Accordingly, high-speed printing is possible as compared with a shuttle type head in which the print head reciprocates in a direction (main scanning direction) orthogonal to the paper transport direction, and productivity can be improved.

  In this example, the configuration of KCMY standard colors (four colors) is illustrated, but the combination of ink colors and the number of colors is not limited to this embodiment, and light ink and dark ink are added as necessary. May be. For example, it is possible to add a print head that discharges light ink such as light cyan and light magenta.

  As shown in FIG. 1, the ink storage / loading unit 14 has tanks that store inks of colors corresponding to the print heads 12K, 12C, 12M, and 12Y, and each tank has a pipeline that is not shown. The print heads 12K, 12C, 12M, and 12Y communicate with each other. Further, the ink storage / loading unit 14 includes notifying means (display means, warning sound generating means, etc.) for notifying when the ink remaining amount is low, and has a mechanism for preventing erroneous loading between colors. is doing.

  The print detection unit 24 includes an image sensor (line sensor or the like) for imaging the droplet ejection result of the print unit 12, and means for checking nozzle clogging and other ejection defects from the droplet ejection image read by the image sensor. Function as.

  The print detection unit 24 of this example is composed of a line sensor having a light receiving element array that is wider than at least the ink ejection width (image recording width) by the print heads 12K, 12C, 12M, and 12Y. The line sensor includes an R sensor row in which photoelectric conversion elements (pixels) provided with red (R) color filters are arranged in a line, a G sensor row provided with green (G) color filters, The color separation line CCD sensor includes a B sensor array provided with a blue (B) color filter. Instead of the line sensor, an area sensor in which the light receiving elements are two-dimensionally arranged can be used.

  The print detection unit 24 reads the test pattern printed by the print heads 12K, 12C, 12M, and 12Y for each color, and detects the ejection of each head. The ejection determination includes the presence / absence of ejection, measurement of dot size, measurement of dot landing position, and the like.

  A post-drying unit 42 is provided following the print detection unit 24. The post-drying unit 42 is means for drying the printed image surface, and for example, a heating fan is used. Since it is preferable to avoid contact with the printing surface until the ink after printing is dried, a method of blowing hot air is preferred.

  When printing on porous paper with dye-based ink, the weather resistance of the image is improved by preventing contact with ozone or other things that cause dye molecules to break by blocking the paper holes by pressurization. There is an effect to.

  A heating / pressurizing unit 44 is provided following the post-drying unit 42. The heating / pressurizing unit 44 is a means for controlling the glossiness of the image surface, and pressurizes with a pressure roller 45 having a predetermined uneven surface shape while heating the image surface to transfer the uneven shape to the image surface. To do.

  The printed matter generated in this manner is outputted from the paper output unit 26. It is preferable that the original image to be printed (printed target image) and the test print are discharged separately. The ink jet recording apparatus 10 is provided with sorting means (not shown) for switching the paper discharge path in order to select the print product of the main image and the print product of the test print and send them to the discharge units 26A and 26B. ing. Note that when the main image and the test print are simultaneously formed in parallel on a large sheet, the test print portion is separated by a cutter (second cutter) 48. The cutter 48 is provided immediately before the paper discharge unit 26, and cuts the main image and the test print unit when the test print is performed on the image margin. The structure of the cutter 48 is the same as that of the first cutter 28 described above, and includes a fixed blade 48A and a round blade 48B.

  Although not shown, the paper output unit 26A for the target prints is provided with a sorter for collecting prints according to print orders.

[Print head structure]
Next, the structure of the print head will be described. Since the structures of the print heads 12K, 12C, 12M, and 12Y provided for the respective ink colors are common, the print heads are represented by reference numeral 50 in the following.

  FIG. 3 is a perspective view of the print head 50, and FIG. 4 is a plan view of a surface (ink ejection surface) 50 </ b> A of the print head 50 that faces the recording paper 16. As shown in FIGS. 3 and 4, nozzles 51 for ejecting ink droplets are disposed on the ink ejection surface 50 </ b> A of the print head 50 along the main scanning direction orthogonal to the sub-scanning direction (paper transport direction). Straightly arranged in a one-dimensional manner at regular intervals, and on the opposite surface (ink supply surface) 50B, ink supply ports 53 are arranged straight in a one-dimensional manner at regular intervals along the main scanning direction. .

  The print head 50 has a structure in which a number of pressure chamber units (droplet discharge elements) 60 having nozzles 51 and ink supply ports 53 are stacked in the main scanning direction. The structure of the pressure chamber unit 60 will be described in detail later. Each pressure chamber unit 60 is a laminated body in which a plurality of ceramic green sheets are laminated in the main scanning direction. In addition, the thickness of each pressure chamber unit 60 in the stacking direction (main scanning direction) is not particularly limited, but may be, for example, 10 to several tens of μm.

  Inside each pressure chamber unit 60, a pressure chamber 52 communicating with the nozzle 51 and the ink supply port 53 is formed. Each ink supply port 53 communicates with a tank of the ink storage / loading unit 14 (see FIG. 1) via a conduit (not shown), and ink is supplied from the tank to each pressure chamber 52 via each ink supply port 53. Distributed supply.

  Each pressure chamber unit 60 is provided with a piezoelectric element (not shown in FIG. 3, described as reference numeral 58 in FIG. 5). Although the configuration of the piezoelectric element 58 will be described later, both sides of a piezoelectric plate formed of a piezoelectric material are sandwiched between a drive electrode and a common electrode. The drive electrode of the piezoelectric element 58 of each pressure chamber unit 60 is drawn and exposed to the upstream surface 50C in the sub-scanning direction (front surface in FIG. 3) of the print head 50, and the upstream surface 50C in the sub-scanning direction of the print head 50. Are respectively connected to drive circuits 90 provided in the circuit. On the other hand, the common electrode of the piezoelectric element 58 of each pressure chamber unit 60 is pulled out to the downstream surface (back surface in FIG. 3) 50D of the print head 50 in the sub-scanning direction, and is exposed and grounded. The mounting position of the drive circuit 90 is not limited to the example shown in FIG.

  FIG. 5 is an exploded perspective view of the pressure chamber unit 60. As shown in the figure, the pressure chamber unit 60 has a structure in which five ceramic green sheets (62, 64, 66, 68, 70) are stacked in the main scanning direction. A base plate 62, a cavity plate 64, a vibration plate (vibration plate) 66, a piezoelectric plate 68, and a protection plate 70 are arranged in order from the upstream side in the main scanning direction (left side in FIG. 5).

  On the downstream side of the base plate 62 in the main scanning direction (right side in FIG. 5), a cavity plate 64 in which holes 65 corresponding to the nozzles 51, the pressure chambers 52, and the ink supply ports 53 are formed is laminated. Laminated.

  A common electrode 72 is formed on the surface of the vibration plate 66 on the downstream side in the main scanning direction (opposite to the pressure chamber 52 side). The piezoelectric plate 68 laminated on the vibration plate 66 on the downstream side in the main scanning direction (the common electrode 72 side) is formed of a piezoelectric material. A drive electrode 74 is formed on the surface of the vibration plate 66 on the downstream side in the main scanning direction (opposite to the common electrode 72 side). The common electrode 72 and the drive electrode 74 are integrally formed with lead electrode portions 72A and 74A that are drawn to the opposite side surfaces and exposed. The lead-out directions of the lead electrode portions 72A and 74A are not limited to the present embodiment, and for example, a configuration in which the lead-out electrode portions 72A and 74A are drawn to the side surfaces in the same direction may be used.

  The piezoelectric element 58 includes a piezoelectric plate 68 sandwiched between a common electrode 72 and a drive electrode 74. When a voltage is applied to the drive electrode 74 of the piezoelectric element 58, the piezoelectric element 58 is displaced in the main scanning direction, and the volume of the pressure chamber 52 is changed via the vibration plate 66. Thereby, the ink filled in the pressure chamber 52 is pressurized and ejected from the nozzle 51 as ink droplets.

  In order not to restrain such displacement of the piezoelectric element 58 in the main scanning direction, a frame-like shape in which holes 71 penetrating both surfaces are formed on the downstream side of the piezoelectric plate 68 in the main scanning direction (drive electrode 74 side). A protective plate 70 is stacked. The protective plate 70 may be configured so as not to restrain displacement of the piezoelectric element 58 in the main scanning direction. For example, the protective plate 70 may be formed with a recess (groove) that opens on the piezoelectric plate 68 side.

  FIG. 6 is a perspective perspective view showing only the piezoelectric plate 68 in the print head 50. In FIG. 6, the print head 50 is indicated by a two-dot chain line. As shown in the figure, the drive electrode 74 formed on the surface of each piezoelectric plate 68 has an extraction electrode portion 74A that is extracted and exposed to the upstream surface (front surface in FIG. 6) 50C of the print head 50 in the sub-scanning direction. ing. The extraction position in the vertical direction in FIG. 6 of the extraction electrode portion 74A of each drive electrode 74 has been changed, and accordingly, the drive circuit 90 (see FIG. 3) disposed on the upstream surface 50C in the sub-scanning direction of the print head 50 is changed. Connection is possible.

  In the print head 50 according to the present embodiment, the drive electrode 74 of each pressure chamber unit 60 is freely disposed on any surface parallel to the main scanning direction that is the stacking direction of the pressure chamber units 60 (except for the ink ejection surface 50A). It is possible to pull out. That is, the drive electrode 74 can be freely drawn out to any of the ink supply surface 50B, the sub scanning direction upstream surface 50C, and the sub scanning direction downstream surface 50D of the print head 50. The same applies to the common electrode 72 of the piezoelectric element 58. Therefore, it is possible to secure a sufficient wiring space for the electrical system of the print head 50.

[Print head manufacturing method]
7A and 7B are explanatory views showing the manufacturing process of the print head 50. FIG. Below, the manufacturing method of the print head 50 is demonstrated using these figures.

  First, as shown in FIG. 7A, five types of thin plate members (base plate 62, cavity plate 64, vibration plate 66, piezoelectric plate 68, and protective plate 70) are produced. In the present embodiment, each thin plate member (62, 64, 66, 68, 70) is a ceramic green sheet.

  As the ceramic material for the piezoelectric plate 68, a lead-based material or a piezoelectric material such as barium titanate or lead zirconate titanate is used. On the other hand, the ceramic material for the other thin plate members (62, 64, 66, 70) is not particularly limited. For example, zirconia is used, and more preferably, the same ceramic material as that of the piezoelectric plate 68 is used. Is desirable. In this case, the degree of shrinkage of each ceramic green sheet during firing can be kept constant.

  At this time, holes 65 and 71 are formed in the cavity plate 64 and the protection plate 70, respectively, and the binder resin 76 is filled therein. The material of the binder resin 76 is the same as the binder material used for green sheets and printing pastes, and acrylic, polyurethane, nylon, Teflon, silicon, and the like are used.

  Next, the common electrode 72 is formed on the surface of the vibration plate 66 on the piezoelectric plate 68 side, and the drive electrode 74 is formed on the surface of the piezoelectric plate 68 on the protective plate 70 side. The common electrode 72 and the drive electrode 74 are formed by screen printing or the like. For example, a metal such as gold, silver, copper, nickel, or platinum is used as the electrode material.

  Next, as shown in FIG. 7B, a laminate (pressure chamber unit) 60 configured by laminating a base plate 62, a cavity plate 64, a vibration plate 66, a piezoelectric plate 68, and a protective plate 70 in the main scanning direction. Are stacked in the main scanning direction to produce a stacked body 78 corresponding to the print head 50. At this time, the holes 65 and 71 of the cavity plate 64 and the protection plate 70 are filled with a binder resin 76, respectively.

  Next, degreasing and firing are performed by pressurizing the laminated body 78 in the laminating direction (the arrow direction in FIG. 7B). At this time, heat of 600 ° C. to 1400 ° C. is applied to the laminated body 78, the common electrode 72 and the drive electrode 74 are fired, and the ceramic green sheets (62, 64, 66, 68, 70) are fired. The laminated body 78 is integrally configured. Further, the binder resin 76 filled in the holes 65 and 71 of the cavity plate 64 and the protection plate 70 is burned out, and the nozzles 51 and the pressure chambers 52 corresponding to the holes 65 are provided in each pressure chamber unit 60. In addition, an ink supply port 53 is formed, and a cavity corresponding to the hole 65 is formed.

  Finally, as shown in FIG. 3, the print head 50 can be manufactured by connecting the lead electrode portion 74 </ b> A of each drive electrode 74 to the drive circuit 90.

  As described above, the print head 50 in the present embodiment is configured by stacking a plurality of pressure chamber units 60 including the nozzles 51, the pressure chambers 52, the ink supply ports 53, and the piezoelectric elements 58 in the main scanning direction. In particular, each pressure chamber unit 60 is configured as a laminate in which a plurality of ceramic green sheets are stacked in the main scanning direction, so that the thickness of each pressure chamber unit 60 in the stacking direction (main scanning direction) is extremely reduced. The nozzle rows in the main scanning direction formed on the ink ejection surface 50A of the print head 50 are arranged at a high density with a nozzle pitch of about 10 μm, for example.

  In the print head 50 having such a laminated structure, it is not necessary to increase the size of the print head 50 in the sub-scanning direction in order to realize high density printing. Therefore, the accuracy of the distance between the ink ejection surface 50A of the print head 50 and the recording paper 16 is good, and variations in the landing positions of the ink droplets ejected from the nozzles 51 are prevented.

  In addition, the direction in which the drive electrode 74 and the common electrode 72 of each piezoelectric element 58 are drawn out can be freely set on any plane parallel to the main scanning direction that is the stacking direction of the pressure chamber units 60 (except for the ink ejection surface 50A). It is possible to pull out. As a result, a sufficient wiring space in the electrical system of the print head 50 can be secured, and the degree of freedom in wiring is dramatically improved.

[Second Embodiment]
FIG. 8 is an explanatory diagram of the second embodiment. The upper part represents the ink ejection surface 50A of the print head 50, the middle part represents the projection nozzle row projected so as to be aligned in the main scanning direction, and the lower part represents the recording paper. Represents dots formed on the surface.

  As shown in the upper part of the drawing, the print head 50 of the present embodiment is a stack in which pressure chamber units 60A, 60B, and 60C having nozzles 51A, 51B, and 51C having different positions in the sub-scanning direction are alternately stacked in the main scanning direction. Is the body. In this print head 50, the positions in the sub-scanning direction of adjacent nozzles in the projection nozzle row projected so as to be aligned in the main scanning direction are different.

  When printing one line in the main scanning direction of the recording paper 16, the nozzles 51A, 51B, 51C are set as one block, and the nozzles 51A, 51B, 51C are sequentially driven according to the conveyance speed of the recording paper 16. That is, a drive voltage with a phase shifted by a predetermined amount is applied to the drive electrode 74 of the piezoelectric element 58 corresponding to each nozzle 51A, 51B, 51C, and each nozzle 51A, 51B, 51C ejects ink at different drive timings. . As a result, the adjacent nozzles in the projection nozzle row do not discharge ink at the same drive timing, thereby preventing crosstalk between the nozzles. In particular, the present invention is effective for a system in which the pressure chamber units 60 are arranged at a high density (for example, about 10 μm pitch) and the influence of crosstalk between adjacent pressure chamber units is large as in the present invention.

  Further, when printing a plurality of lines (three lines in FIG. 8) in the main scanning direction of the recording paper 16, the adjacent nozzles in the projection nozzle row do not discharge ink at the same drive timing. It is preferable that the relationship between the nozzle pitch Pn and the dot pitch Pd in the sub-scanning direction satisfies the following formula.

Pn = (n + k) × Pd (1)
Here, n is a positive integer and 0 <k <1. As a result, crosstalk between adjacent nozzles in the projection nozzle row can be more reliably prevented.

  9A to 9C are perspective perspective views showing the cavity plates 64A, 64B, and 64C in the pressure chamber units 60A, 60B, and 60C. As shown in these drawings, nozzles 51A, 51B, and 51C are formed in the cavity plates 64A, 64B, and 64C at different positions in the sub-scanning direction, respectively. The other plate members constituting the pressure chamber units 60A, 60B, and 60C are the same as those in the first embodiment, and are not shown. The pressure chamber units 60A, 60B, and 60C are indicated by two-dot chain lines. it's shown.

  By the way, in the print head 50 shown in FIG. 8, there is a unique nozzle pair in which the pitch between nozzles in the sub-scanning direction is different from other nozzles among adjacent nozzles in the projection nozzle row projected so as to be aligned in the main scanning direction. . For example, in the example of FIG. 8, the inter-nozzle pitch Ps in the sub-scanning direction between the nozzle 51C-1 and the nozzle 51A-2 adjacent to each other in the projection nozzle row is between the nozzles 51A-1 and 51B-1 or between the nozzles 51B-1 and 51C. −1, which is larger than the inter-nozzle pitch Pn in the sub-scanning direction, and the nozzle 15C-1 and the nozzle 51A-2 form a unique nozzle pair. When such a unique nozzle pair exists, density unevenness is visually recognized in an image formed on the recording paper due to a shift in the mounting angle of the print head 50.

  Note that the manufacturing method of the print head 50 in the second embodiment is the same as that in the first embodiment, and a description thereof will be omitted.

  10 and 11 are modifications of the second embodiment, and represent a print head 50 that does not have such a unique nozzle pair.

  The print head 50 shown in FIG. 10 is configured by changing the lamination pattern of the print head 50 shown in FIG. 8, and is called pressure chamber units 60B, 60A, 60B, 60C, 60B, 60A,. Laminated in order. In the print head 50, the inter-nozzle pitches Pn in the sub-scanning direction between adjacent nozzles in the projection nozzle row projected so as to be aligned in the main scanning direction are all configured to be the same.

  The print head 50 shown in FIG. 11 is obtained by alternately stacking two types of pressure chamber units 60A and 60B in the main scanning direction. Similarly to FIG. 10, the print head 50 is also configured so that the nozzle pitches Pn in the sub-scanning direction between adjacent nozzles in the projection nozzle row projected so as to be aligned in the main scanning direction are the same.

  As described above, in the modified example of the second embodiment shown in FIGS. 10 and 11, crosstalk between adjacent nozzles in the projection nozzle row projected so as to be aligned in the main scanning direction is prevented, and further, Since the nozzle pitches in the sub-scanning direction between adjacent nozzles in the projection nozzle row are all the same, density unevenness due to such a unique nozzle pair does not occur. Since the print head 50 (see FIGS. 3 and 4) in the first embodiment has nozzle rows arranged in a single row at regular intervals in the main scanning direction as described above, the unique nozzle pair as described above. Does not exist.

  In addition, the kind and lamination | stacking pattern of the pressure chamber unit 60 are not limited to this example, For example, four or more types of pressure chamber units 60 may be laminated | stacked by a fixed pattern, and may be laminated | stacked at random. In the present invention, the amount is preferably small enough to prevent crosstalk, and more preferably, two or three types of pressure chamber units 60 are alternately stacked in the main scanning direction.

  In each of the above embodiments, the case where the print head 50 is a full line type head has been described. However, the present invention is not limited to this, and may be a shuttle type head.

  The liquid ejection head and the liquid ejection head manufacturing method of the present invention have been described in detail above, but the present invention is not limited to the above examples, and various improvements and modifications can be made without departing from the scope of the present invention. Of course you may go

1 is an overall schematic diagram of an ink jet recording apparatus. FIG. 2 is a plan view of a main part around a printing unit of the inkjet recording apparatus shown in FIG. 1. It is a perspective view of a print head. FIG. 3 is a plan view of an ink discharge surface of a print head. It is a disassembled perspective view of a pressure chamber unit. FIG. 6 is a perspective perspective view showing only a piezoelectric plate in the print head. (A), (b) is explanatory drawing showing the manufacturing process of the print head. FIG. 10 is a plan view of an ink ejection surface of a print head according to a second embodiment. (A)-(c) is a perspective perspective view showing the cavity plate in a pressure chamber unit. It is one modification of 2nd Embodiment. It is another modification of 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Inkjet recording device, 16 ... Recording paper, 50 ... Print head, 51 ... Nozzle, 52 ... Pressure chamber, 53 ... Ink supply port, 58 ... Piezoelectric element, 60 ... Pressure chamber unit, 62 ... Base plate, 64 ... Cavity plate , 65 ... hole, 66 ... vibrating plate, 68 ... piezoelectric plate, 70 ... protection plate, 71 ... hole, 72 ... common electrode, 72A ... extraction electrode, 74 ... drive electrode, 74A ... extraction electrode, 76 ... Binder resin

Claims (9)

  A pressure chamber unit having at least a nozzle for discharging liquid, a pressure chamber for filling the liquid, a supply port for supplying the liquid to the pressure chamber, and a piezoelectric element for displacing the wall surface of the pressure chamber. A liquid discharge head comprising a plurality of stacked layers in a direction.   The liquid ejection head according to claim 1, wherein a plurality of the substantially thin plate-like piezoelectric elements are arranged in a thickness direction of the piezoelectric elements corresponding to the first direction.   The liquid discharge head according to claim 1, wherein the pressure chamber unit is configured by laminating a plurality of ceramic green sheets in the first direction.   4. The liquid ejection head according to claim 1, wherein the nozzles are arranged one-dimensionally in the first direction. 5.   The position of the 2nd direction substantially orthogonal to the said 1st direction of the nozzles which adjoin by the projection nozzle row projected so that it may line up in the said 1st direction differs. Item 4. The liquid discharge head according to any one of Item 3.   When the pitch between dots in the second direction formed on the recording medium is Pd, n is a positive integer, and 0 <k <1, the second nozzle adjacent to the first nozzle in the projection nozzle row is: The liquid ejection head according to claim 5, wherein the liquid ejection head is disposed so as to be shifted by (n + k) × Pd in the second direction with respect to the first nozzle. The first direction is a main scanning direction that is substantially orthogonal to the relative conveyance direction of the recording medium with respect to the liquid ejection head;
The liquid ejection head according to claim 1, wherein the second direction is a sub-scanning direction that is a relative conveyance direction of the recording medium with respect to the liquid ejection head. A laminate of a plurality of ceramic green sheets having at least a nozzle for discharging liquid, a pressure chamber for filling the liquid, a supply port for supplying the liquid to the pressure chamber, and a piezoelectric element for displacing the wall surface of the pressure chamber A method of manufacturing a liquid discharge head configured by laminating a plurality of layers in the first direction,
A binder filling step of filling a hole resin or a groove corresponding to the pressure chamber with a binder resin;
And a step of performing a debinding process and baking after laminating the laminated body in the first direction. The method of manufacturing a liquid ejection head according to claim 8, wherein the first direction is a main scanning direction substantially orthogonal to a relative conveyance direction of the recording medium with respect to the liquid ejection head.

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