JP4933765B2 - Method for manufacturing liquid discharge head - Google Patents

Description

  The present invention relates to a method of manufacturing a liquid discharge head, a liquid discharge head, and an image forming apparatus, and more particularly to a manufacturing technique and structure of a liquid discharge head that discharges liquid from nozzles.

  An ink jet recording apparatus equipped with a head (liquid ejection head) that ejects ink droplets from nozzles communicating with a pressure chamber by changing the wall surface of the pressure chamber using displacement of a piezoelectric element and pressurizing ink in the pressure chamber. Are known.

  In recent years, high integration has been required for the heads used in ink jet recording apparatuses, and in order to achieve high integration of the heads and ensure high reliability and high performance, various structures and manufacturing techniques have been made. Has been made.

  In the invention described in Patent Document 1, a piezoelectric film is formed in a state where a vibration plate is bonded to an ink storage chamber, and annealing is performed to generate a thin piezoelectric film, and at a low driving voltage. A method of manufacturing a liquid transfer device that can sufficiently apply pressure to the liquid in the liquid chamber and transfer the liquid from the liquid chamber to the outside even when the piezoelectric body is driven is disclosed.

  In the invention described in Patent Document 2, an intermediate layer is formed between the silicon substrate and the lead-based piezoelectric ceramic, and lead diffusion onto the substrate during the firing of the piezoelectric ceramic on the silicon substrate can be prevented. A technique for realizing an actuator having an intermediate layer with high strength and reliability is disclosed.

In the invention described in Patent Document 3, in the gas deposition method film-formed piezoelectric ceramic pressure film structure, the substrate film is reduced after the intermediate film is disposed on the substrate, thereby reducing the substrate damage and the piezoelectric film. A thick film structure of a piezoelectric ceramic that prevents a decrease in mechanical strength of a multilayer structure composed of a thick ceramic film / substrate is disclosed.
JP 2005-35013 A JP-A-11-204849 JP 2001-152361 A

However, a piezoelectric body such as PZT (Pb (Zr · Ti) O ₃ , lead zirconate titanate) is formed on a diaphragm (substrate) using a metal containing iron such as stainless steel (SUS), and the temperature is 600 ° C. When the annealing process is performed at the above high temperature, there is a problem that iron contained in the vibration plate diffuses into the piezoelectric body and degrades the performance of the piezoelectric body.

  In the invention described in Patent Document 1, since annealing is performed for several hours in a high temperature atmosphere of 600 ° C. to 750 ° C. (AD method) and 600 ° C. to 1200 ° C. (sol-gel method), it is contained in a stainless steel diaphragm. Iron diffuses into the piezoelectric element and degrades the performance of the piezoelectric element. In addition, an atmospheric atmosphere is required for the annealing treatment of piezoelectric elements formed by the AD method (aerosol deposition method), and the surface of the diaphragm that is annealed at the same time is oxidized, resulting in deterioration of durability and other factors. Problems such as a decrease in adhesion to the member occur.

  In the inventions described in Patent Document 2 and Patent Document 3, an intermediate layer is provided between the substrate (substrate) and the piezoelectric ceramic to prevent diffusion of the lead component of the piezoelectric ceramic or the substrate (substrate) during the piezoelectric ceramic film formation. However, it does not describe that the performance of the piezoelectric ceramic deteriorates due to the diffusion of elements contained in the substrate (substrate).

  The present invention has been made in view of such circumstances, and the liquid discharge that prevents the diffusion of the metal element contained in the substrate into the piezoelectric element, ensures the performance and reliability of the piezoelectric element, and realizes preferable liquid discharge. It is an object of the present invention to provide a head manufacturing method, a liquid discharge head, and an image forming apparatus.

In order to achieve the above object, a method of manufacturing a liquid discharge head according to the first aspect of the present invention includes: a thin film forming step of forming a thin film on both surfaces of a diaphragm containing iron; A lower electrode film forming step for forming a lower electrode on one surface on which a thin film is formed, a piezoelectric film forming step for forming a piezoelectric material on the lower electrode, and an upper electrode film on the piezoelectric material After the upper electrode film forming step, after the thin film forming step, a step of bonding a flow path plate to the other surface of the diaphragm on which the thin film is formed, the thin film on the one surface, the lower electrode, and The piezoelectric body is formed, the thin film is formed on the other surface, and the diaphragm to which the flow path plate is bonded is subjected to a heat treatment to generate an oxide film in which the thin film is oxidized, and A heat treatment step for firing the piezoelectric body, and before the flow path plate On the opposite side of the diaphragm, characterized in that it comprises a and a step of joining the nozzle plate a nozzle communicating with the liquid chamber formed in the channel plate so as to correspond to the piezoelectric body is formed.

According to the present invention, the protective film containing oxide is formed between the diaphragm containing iron and the piezoelectric body including the upper electrode and the lower electrode by the heat treatment process, and the piezoelectric body is sintered. Further, the diffusion of iron contained in the substrate into the piezoelectric body is prevented, so that it is possible to avoid the performance deterioration and the reliability reduction of the piezoelectric body. The present invention is particularly effective in an embodiment in which heat treatment is performed at a high temperature of about 600 ° C. to 1200 ° C. The oxide film on the liquid chamber side functions as a liquid-resistant film for the diaphragm.

  Further, the generation of the protective film containing the oxide and the firing of the piezoelectric body can be performed by a common heat treatment process, which contributes to simplification of the manufacturing process.

  This heat treatment step includes heat treatment (annealing treatment) in a high temperature environment of 600 ° C. to 1200 ° C.

In order to achieve the above object, a method of manufacturing a liquid discharge head according to the second aspect of the present invention includes a thin film forming step of forming a thin film on both surfaces of a diaphragm containing iron, and the thin film A first heat treatment step in which an oxide film is formed by heat-treating the formed diaphragm to oxidize the thin film; and a lower portion in which a lower electrode is formed on one surface of the diaphragm on which the oxide film is formed After the electrode film forming step, the piezoelectric film forming step for forming a piezoelectric material on the lower electrode, the upper electrode film forming step for forming the upper electrode on the piezoelectric material, and the first heat treatment step, Joining the flow path plate to the other surface of the diaphragm on which the thin film is formed, forming the oxide film on the one surface, forming the lower electrode and the piezoelectric body, and forming the other electrode The oxide film is formed on the surface and the flow path plate is in contact with the surface. A second heat treatment step of firing the piezoelectric body by subjecting the diaphragm to heat treatment, and the flow path plate on the opposite side of the flow path plate from the vibration plate, corresponding to the piezoelectric body. Joining a nozzle plate in which a nozzle communicating with the liquid chamber is formed.

According to the second aspect of the present invention, the protective film is generated on the diaphragm by the first heat treatment step, and the piezoelectric body is baked by the second heat treatment step performed after the protective film is generated. It is possible to increase the effect of preventing diffusion of the piezoelectric material. The oxide film on the liquid chamber side functions as a liquid-resistant film for the diaphragm. That is, according to the first and second aspects of the invention, by forming protective films on both surfaces of the diaphragm, it is possible to protect the surface opposite to the surface on which the piezoelectric body is formed. For example, when the surface of the substrate on which the piezoelectric body is formed is the first surface and the surface opposite to the first surface is the second surface, a liquid chamber for storing liquid is formed on the second surface. In this embodiment, the protective film formed on the second surface functions as a liquid-resistant film that protects the substrate (vibrating plate) from the liquid in the liquid chamber.

  A third aspect of the present invention relates to an aspect of the method for manufacturing a liquid discharge head according to the first or second aspect, wherein the thin film contains titanium and aluminum.

  According to the third aspect of the present invention, it is possible to easily form an oxide film that serves as a protective film of the substrate by using an easily available material such as titanium or aluminum. Further, when titanium dioxide or aluminum oxide, which is an oxide of titanium and aluminum, is applied as a protective film, a high iron diffusion preventing effect can be obtained.

  Note that the thin film containing titanium and aluminum includes TiAlN (titanium aluminum nitride) and TiCrAlN (titanium chromium aluminum nitride).

  A fourth aspect of the present invention relates to an aspect of the method for manufacturing a liquid discharge head according to the first, second, or third aspect, and a liquid chamber that forms a liquid chamber for storing a liquid to which a discharge force is applied from the piezoelectric body. And forming a nozzle that communicates with the liquid chamber and discharges the liquid.

The liquid chamber forming step has a mode in which a plate (structure) in which a liquid chamber is formed is joined to a diaphragm. Further, the nozzle forming step has a mode in which a nozzle plate in which an opening (hole) to be a nozzle is formed is joined to a plate (structure) in which a liquid chamber is formed. It invention of claim 5 relates to an embodiment of the method of manufacturing the liquid discharge head according to any one of claims 1 to 4, the step of bonding the flow path plate, a diffusion bonding process It is characterized by. A sixth aspect of the present invention relates to an aspect of the method for manufacturing a liquid discharge head according to the fifth aspect, wherein the diffusion bonding step is performed in a vacuum environment or an inert gas environment. . A seventh aspect of the present invention relates to an aspect of the method for manufacturing a liquid discharge head according to the fifth or sixth aspect, wherein the diffusion bonding step is heated to a temperature equal to or higher than a recrystallization temperature of the vibration plate and the channel plate. It is characterized by being carried out. The invention according to claim 8 relates to an aspect of the method of manufacturing a liquid discharge head according to any one of claims 5 to 7, wherein the diffusion bonding step is 4.9 to 19.6 megapascals. It is characterized by being performed under pressure conditions below Pascal.

Further , according to the method for manufacturing a liquid discharge head according to the present invention, the diaphragm containing iron and the oxide formed on one surface of the diaphragm and oxidizing the thin film formed on the diaphragm A second protective film containing an oxide formed by oxidizing the thin film formed on the diaphragm and formed on the other surface of the diaphragm; A lower electrode formed on the first protective film side, a piezoelectric body formed on the opposite side of the lower electrode to the first protective film, and formed on the opposite side of the piezoelectric body to the lower electrode. An upper electrode, a flow path plate bonded to the diaphragm on the second protective film side and forming a liquid chamber corresponding to the piezoelectric body, and opposite to the second protective film of the flow path plate It is joined to the side, and a nozzle plate in which the nozzle is formed that communicates with the liquid chamber, Ru includes a liquid discharge Head is manufactured.

In such a liquid discharge head , a protective film containing an oxide is formed between a vibration plate containing iron and a piezoelectric body provided with an upper electrode and a lower electrode. The diffusion of iron contained in the piezoelectric material to the piezoelectric body can be prevented, and performance deterioration and reliability reduction of the piezoelectric body can be avoided. The oxide film on the liquid chamber side functions as a liquid-resistant film for the diaphragm. Diaphragm which deforms in response to flexural deformation of the piezoelectric body, the piezoelectric body utilizing the displacement of d ₃₁ mode is preferably used.

  If the surface of the substrate on which the piezoelectric body is formed is the first surface and the surface opposite to the first surface is the second surface, the protective film may be formed on the first surface. Of course, a protective film may be formed on both the first surface and the second surface.

  The liquid ejection head includes a line-type head having a nozzle row having a length corresponding to the entire width of the recording medium (image forming width of the recording medium), and a short head having a nozzle row having a length less than the entire width of the recording medium. There is a serial type head that scans in the width direction of the recording medium.

  In the line type liquid discharge head, short heads having short nozzle rows that are less than the length corresponding to the full width of the recording medium are arranged in a staggered manner and connected to form a length corresponding to the full width of the recording medium. Also good.

  Examples of the liquid include chemicals such as ink and resist used in the ink jet recording apparatus, processing liquid, and the like. This liquid has physical properties (viscosity, etc.) that can be discharged from a nozzle provided in the liquid discharge head.

  The recording medium is a medium to which the liquid ejected from the ejection holes is attached, and is a continuous sheet, a cut sheet, a seal sheet, a resin sheet such as an OHP sheet, a film, a cloth, and other various media and shapes. including.

In the liquid ejection head, the thin film may include aluminum and titanium, the oxide, aspects containing aluminum oxide and titanium dioxide are also preferred.

In such a liquid discharge head , it is also preferable that the protective film has a thickness of 50 nanometers or more and 15 micrometers or less.

According to this aspect , in the aspect in which the protective film is 50 nanometers or more, the diffusion of iron to the piezoelectric body is reliably prevented, and in the aspect in which the protective film is 15 micrometers or less, the thickness of the substrate is large. As a result, it is possible to avoid a decrease in the transmission efficiency of the pressure generated by the piezoelectric body.

In the liquid ejection head, the flow path plate, stainless steel, also embodiments comprising titanium, titanium alloy, aluminum, any material of the aluminum alloy.

In such a liquid discharge head , it is also preferable that the flow path plate is formed using a green sheet in which glass powder is dispersed in a resin binder.

In such a liquid discharge head , the glass composition contained in the green sheet is not softened by a temperature condition of a heat treatment for firing the piezoelectric body.

The flow path plate may include a liquid chamber that stores a liquid to which a discharge force is applied from the piezoelectric body, and a nozzle that communicates with the liquid chamber and discharges the liquid.

In such an embodiment, the substrate may be composed of a plurality of thin films (plate members). For example, the substrate may be formed by laminating a thin film (cavity plate) on which a liquid chamber or a nozzle is formed, or the liquid chamber is formed by a technique such as etching, and the thin film on which the nozzle is formed is bonded to the substrate. A substrate may be formed. The nozzle here includes an opening through which liquid is discharged, and a flow path that connects the opening and the liquid chamber.

  Among image forming apparatuses, there is an ink jet recording apparatus that forms a desired image by ejecting ink from a nozzle onto a medium (recording medium). The image referred to here includes not only so-called images such as photographs and pictures, but also text such as characters and symbols, and shapes such as wiring patterns formed on a wiring board.

  According to the present invention, the protective film containing the oxide is formed between the iron-containing substrate and the piezoelectric body including the upper electrode and the lower electrode by the heat treatment process, and the piezoelectric body is sintered. Since diffusion of iron contained in the substrate into the piezoelectric body is prevented, it is possible to avoid performance deterioration and reliability reduction of the piezoelectric body. The present invention is particularly effective in an embodiment in which heat treatment is performed at a high temperature of about 600 ° C. to 1200 ° C. In addition, after the first heat treatment is performed on the thin film formed on the substrate to form an oxide film, the lower electrode and the piezoelectric body are formed on the substrate, and the piezoelectric body is baked by the second heat treatment step. A diffusion preventing effect can be obtained.

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

[Overall configuration of inkjet recording apparatus]
FIG. 1 is an overall configuration diagram showing an outline of an ink jet recording apparatus according to an embodiment of the present invention. As shown in FIG. 1, the inkjet recording apparatus 10 supplies a print unit 12 having a plurality of heads 12K, 12C, 12M, and 12Y provided for each ink color, and the heads 12K, 12C, 12M, and 12Y. An ink storage / loading unit 14 for storing ink to be stored, a paper feeding unit 18 for supplying the recording paper 16, a decurling unit 20 for removing curling of the recording paper 16, and heads 12K, 12C, 12M, and 12Y. A suction belt conveyance unit 22 that conveys the recording paper 16 while maintaining the flatness of the recording paper 16 (recording medium), and a print that reads the printing result by the printing unit 12 and is arranged to face the nozzle surface (ink ejection surface). A detection unit 24 and a paper discharge unit 26 that discharges printed recording paper (printed matter) to the outside are provided.

  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 faces at least the nozzle surfaces of the heads 12K, 12C, 12M, and 12Y and the sensor surface of the print detection unit 24. The part to be made is a 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 printing unit 12 and the sensor surface of the printing 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 the motor (not shown in FIG. 1 and indicated by reference numeral 88 in FIG. 5) is transmitted to at least one of the rollers 31 and 32 around which the belt 33 is wound, so that the belt 33 rotates clockwise in FIG. 1 and the recording paper 16 held on the belt 33 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 conveyance mechanism instead of the suction belt conveyance unit 22 is also conceivable, if the roller / nip conveyance is performed in the printing area, the roller comes into contact with the printing 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 has a so-called full line type head in which a line type head having a length corresponding to the maximum paper width is arranged in a direction (main scanning direction) orthogonal to the paper feeding direction (sub scanning direction). . Each of the heads 12K, 12C, 12M, and 12Y constituting the printing unit 12 has a plurality of ink discharge ports (nozzles) arranged over a length exceeding at least one side of the maximum size recording paper 16 targeted by the inkjet recording apparatus 10. Line type head.

  Heads 12K, 12C, and 12M corresponding to the respective color inks 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 of the recording paper 16. , 12Y are arranged. A color image can be formed on the recording paper 16 by ejecting the color ink from each of the heads 12K, 12C, 12M, and 12Y while conveying the recording paper 16.

  Thus, according to the printing unit 12 in which the full line head that covers the entire area of the paper width is provided for each ink color, the operation of relatively moving the recording paper 16 and the printing unit 12 in the paper feeding direction is performed once. It is possible to record an image on the entire surface of the recording paper 16 only by performing it (that is, in one sub-scan). Thus, high-speed printing is possible and productivity can be improved as compared with a shuttle-type head in which the head reciprocates in the main scanning direction orthogonal to the paper feed direction.

  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 head for ejecting light-colored 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 heads 12K, 12C, 12M, and 12Y, and each tank is connected via a conduit that is not shown. The 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) of the 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 patterns printed by the 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 surface uneven 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.

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

  FIG. 3A is a plan perspective view showing an example of the structure of the head 50, and FIG. 3B is an enlarged view of a part thereof. FIG. 3C is a perspective plan view showing another structural example of the head 50.

  In order to increase the dot pitch printed on the recording paper 16, it is necessary to increase the nozzle pitch in the head 50. As shown in FIGS. 3A to 3C, the head 50 of this example includes a plurality of ink chamber units each including a nozzle 51 serving as an ink droplet ejection hole, a pressure chamber 52 corresponding to each nozzle 51, and the like. 53 is arranged in a zigzag matrix (two-dimensionally), so that it is projected substantially in a line along the longitudinal direction of the head (main scanning direction orthogonal to the paper feed direction). High density of nozzle spacing (projection nozzle pitch) is achieved.

  The form in which one or more nozzle rows are formed in the main scanning direction substantially orthogonal to the paper feed direction over a length corresponding to the entire width of the recording paper 16 is not limited to this example. For example, instead of the configuration of FIG. 3 (a), as shown in FIG. 3 (c), short head blocks 50 ′ in which a plurality of nozzles 51 are two-dimensionally arranged are arranged in a zigzag pattern and connected together. Thus, a line head having a nozzle row having a length corresponding to the entire width of the recording paper 16 may be configured.

  In this example, the planar shape of the pressure chamber 52 is a substantially square shape, but the planar shape of the pressure chamber 52 is not limited to a substantially square shape, and may be a substantially circular shape, a substantially elliptical shape, or a substantially parallelogram ( Various shapes such as diamonds can be applied. Further, the arrangement of the nozzle 51 and the supply port 54 is not limited to the arrangement shown in FIGS. 3A to 3C, and the nozzle 51 may be arranged in the substantially central portion of the pressure chamber 52. The supply port 54 may be disposed on the side wall side.

  As shown in FIG. 3 (b), a large number of arrays are arranged in a lattice pattern with a constant array pattern along the row direction along the main scanning direction and the oblique column direction having a constant angle θ not orthogonal to the main scanning direction. By doing so, the high-density nozzle head of this example is realized.

  That is, with a structure in which a plurality of ink chamber units 53 are arranged at a constant pitch d along the direction of an angle θ with respect to the main scanning direction, the pitch P of the nozzles projected so as to be aligned in the main scanning direction is d × cos θ. Thus, in the main scanning direction, each nozzle 51 can be handled equivalently as a linear arrangement with a constant pitch P. With such a configuration, it is possible to realize a high-density nozzle configuration in which 2400 nozzle rows are projected per inch (2400 nozzles / inch) so as to be aligned in the main scanning direction.

  In implementing the present invention, the nozzle arrangement structure is not limited to the illustrated example, and various nozzle arrangement structures such as an arrangement structure having one nozzle row in the sub-scanning direction can be applied.

  When driving a nozzle with a full line head having a nozzle row having a length corresponding to the entire printable width, (1) all the nozzles are driven simultaneously, (2) the nozzles are sequentially moved from one side to the other. (3) The nozzles are divided into blocks, and each block is sequentially driven from one side to the other, etc., and one line (in one row of dots) in the width direction (main scanning direction) of the recording medium Driving a nozzle that prints a line or a line composed of a plurality of rows of dots is defined as main scanning.

  In particular, when driving the nozzles 51 arranged in a matrix as shown in FIGS. 3A to 3C, the main scanning as described in the above (3) is preferable.

  On the other hand, by moving the above-described full line head and the recording paper 16 relative to each other, printing of one line (a line composed of a single line of dots or a line composed of a plurality of lines of dots) formed by the above-described main scanning is repeatedly performed. This is defined as sub-scanning.

  4 is a cross-sectional view (a cross-sectional view taken along line 4-4 in FIGS. 3A and 3B) showing a three-dimensional configuration of the ink chamber unit 53. FIG.

  As shown in FIG. 4, the pressure chamber 52 provided corresponding to each nozzle 51 has a substantially square planar shape, and the nozzle 51 and the supply port 54 are provided at both corners on the diagonal line. ing. Each pressure chamber 52 communicates with a common flow path (common liquid chamber) 55 through a supply port 54. The common flow channel 55 communicates with an ink supply tank (not shown), and ink supplied from the ink supply tank is distributed and supplied to each pressure chamber 52 via the common flow channel 55.

  Bonded to the diaphragm 56 constituting the top surface of the pressure chamber 52 is an upper electrode 57 using a metal such as platinum (Pt) or gold (Au), and a piezoelectric element 58 including a lower electrode 57A and a piezoelectric body 58A. Is done. In this specification, a state in which the upper electrode 57 and the lower electrode 57A are formed on both surfaces of the piezoelectric body 58A is referred to as a piezoelectric element 58.

  By applying a predetermined drive voltage to the piezoelectric element 58 (that is, between the upper electrode 57 and the lower electrode 57A), the piezoelectric element 58 is deformed flexibly, and the diaphragm 56 is deformed in response to the deflected deformation, and the nozzle. Ink is ejected from 51. When ink is ejected from the nozzle 51, new ink is supplied from the common flow channel 55 through the supply port 54 to the pressure chamber 52.

A metal such as stainless steel is used for the diaphragm 56 in this example. For the piezoelectric element 58, a ceramic piezoelectric element such as PZT (Pb (Zr · Ti) O ₃ , lead zirconate titanate) is preferably used.

In the head 50 of this example, a protective film 59 is formed between the diaphragm 56 and the piezoelectric element 58. The protective film 59 includes alumina (Al ₂ O ₃ ), titania (TiO ₂ ), chromium oxide ( A metal oxide film such as CrO ₂ ) is applied.

  A metal film containing aluminum (Al) and titanium (Ti) is formed on the surface 56A of the diaphragm 56 on the side where the piezoelectric element 58 is disposed by a thin film forming method such as an ion plating method, a sol-gel method, or a sputtering method. When the piezoelectric element 58 is annealed at 600 ° C. to 1200 ° C., metal elements such as aluminum and titanium contained in the metal film are oxidized, and the above-described metal oxide film is formed on the surface of the diaphragm 56. Is formed.

  The metal film formed on the diaphragm 56 only needs to contain at least aluminum and titanium, and may further contain chromium (Cr). For the metal film, a hard film such as TiAlN (titanium aluminum nitride) or TiCrAlN (titanium chromium aluminum nitride) is preferably used.

  According to the structure of the head 50 shown in FIG. 4, iron (Fe) contained in the diaphragm 56 even if the annealing process (treatment temperature 600 ° C. to 1200 ° C.) is performed with the piezoelectric element 58 bonded to the diaphragm 56. ) Does not diffuse into the piezoelectric element 58 (piezoelectric body 58A), and performance degradation and reliability degradation of the piezoelectric element 58 are prevented.

  Alternatively, the pre-annealing process may be performed in a state where the metal film is formed on the vibration plate 56, the piezoelectric element 58 may be formed on the vibration plate 56 on which the protective film 59 is formed, and the annealing process may be further performed.

  The film thickness of the protective film 59 is preferably 50 nm or more and 15 μm or less. That is, if the thickness of the protective film 59 is less than 50 nm, the function of preventing the diffusion of iron to the piezoelectric element 58 does not work sufficiently, and if the thickness of the protective film 59 exceeds 15 μm, the protective film 59 vibrates. It functions as the plate 56 (the thickness of the diaphragm 56 is increased by the thickness of the protective film 59), and even when a predetermined pressure is generated from the piezoelectric element 58, the displacement amount of the diaphragm 56 is reduced, and a predetermined discharge performance is achieved. It becomes difficult to maintain.

In this example, the protective film 59 composed of one layer is shown, but the protective film 59 may be composed of two or more layers. Different films (elements contained) can be applied to two or more layers.
[Explanation of control system]
FIG. 5 is a principal block diagram showing the system configuration of the inkjet recording apparatus 10. The inkjet recording apparatus 10 includes a communication interface 70, a system controller 72, a memory 74, a motor driver 76, a heater driver 78, a print control unit 80, an image buffer memory 82, a head driver 84, and the like.

  The communication interface 70 is an interface unit that receives image data sent from the host computer 86. As the communication interface 70, a serial interface such as USB (Universal serial bus), IEEE 1394, Ethernet (registered trademark), a wireless network, or a parallel interface such as Centronics can be applied. In this part, a buffer memory (not shown) for speeding up communication may be mounted. The image data sent from the host computer 86 is taken into the inkjet recording apparatus 10 via the communication interface 70 and temporarily stored in the memory 74. The memory 74 is a storage unit that temporarily stores an image input via the communication interface 70, and data is read and written through the system controller 72. The memory 74 is not limited to a memory made of a semiconductor element, and a magnetic medium such as a hard disk may be used.

  The system controller 72 is a control unit that controls the communication interface 70, the memory 74, the motor driver 76, the heater driver 78, and the like. The system controller 72 includes a central processing unit (CPU) and its peripheral circuits, and performs communication control with the host computer 86, read / write control of the memory 74, and the like, and controls the motor 88 and heater 89 of the transport system. A control signal to be controlled is generated.

  The motor driver 76 is a driver (drive circuit) that drives the motor 88 in accordance with an instruction from the system controller 72. The heater driver 78 is a driver that drives a heater 89 such as the post-drying unit 42 (shown in FIG. 1) in accordance with an instruction from the system controller 72.

  The print control unit 80 has a signal processing function for performing various processing and correction processing for generating a print control signal from image data in the memory 74 in accordance with the control of the system controller 72, and the generated print control. A control unit that supplies signals to the head driver 84. Necessary signal processing is performed in the print controller 80, and the ejection amount and ejection timing of the ink droplets of the head 50 and ejection timing (droplet ejection control) are performed via the head driver 84 based on the image data. Thereby, a desired dot size and dot arrangement are realized.

  The print control unit 80 includes an image buffer memory 82, and image data, parameters, and other data are temporarily stored in the image buffer memory 82 when image data is processed in the print control unit 80. In FIG. 5, the image buffer memory 82 is shown in a mode associated with the print control unit 80, but it can also be used as the memory 74. Also possible is an aspect in which the print controller 80 and the system controller 72 are integrated and configured with one processor.

  The head driver 84 drives the piezoelectric elements 58 of the heads 12K, 12C, 12M, and 12Y of the respective colors based on the print data given from the print control unit 80. The head driver 84 may include a feedback control system for keeping the head driving conditions constant.

  Various control programs are stored in the program storage unit 90, and the control programs are read and executed in accordance with instructions from the system controller 72. The program storage unit 90 may use a semiconductor memory such as a ROM or an EEPROM, or may use a magnetic disk or the like. Further, an external interface may be provided and a memory card or PC card may be used. Of course, you may provide several recording media among these recording media. The program storage unit 90 may also be used as a storage unit (not shown) for operating parameters.

As described with reference to FIG. 1, the print detection unit 24 is a block including a line sensor, reads an image printed on the recording paper 16, performs necessary signal processing, and the like to perform a print status (whether ejection is performed, droplet ejection And the detection result is provided to the print control unit 80.
The print controller 80 performs various corrections on the head 50 based on information obtained from the print detector 24 as necessary.

  The system controller 72 and the print control unit 80 may be configured by one processor, a device in which the system controller 72, the motor driver 76, and the heater driver 78 are integrated, or the print control unit 80 and the head. A device in which a driver is integrated may be used.

[Description of head manufacturing method]
Next, a method for manufacturing the head 50 shown in this example will be described. As described with reference to FIG. 4, the head 50 shown in this example has a laminated structure in which a large number of cavity plates are laminated. That is, a nozzle plate in which the nozzle 51 is formed, a flow channel plate in which the pressure chamber 52, the supply port 54, the common flow channel 55, and the like are formed, a vibration plate 56 in which the protective film 59 is formed, an upper electrode 57, and The piezoelectric element 58 having the lower electrode 57A is laminated in order. In addition, each cavity plate mentioned above may be comprised from one plate, and may be comprised from several plates.

For example, the flow path plate includes a plate on which a discharge-side flow path that allows the nozzle 51 and the pressure chamber 52 to communicate, a plate on which a common flow path 55 is formed , a plate on which a supply port 54 is formed, a pressure There is a mode in which the plate on which the chamber 52 is formed is laminated.

  FIG. 6 is an explanatory diagram showing a manufacturing process of the head 50 of this example. Although details will be described later, a joining method corresponding to the material of the plate, such as joining by a joining member, joining by pressurization, or heating, is appropriately selected for joining between the plates.

  In the head manufacturing process shown in this example (step S10), first, in step S12 (plate forming process), each plate constituting the head 50 is formed. For example, a stainless steel or synthetic resin plate is used for the nozzle plate of this example. Moreover, metal plates (thin films) such as stainless steel, titanium, titanium alloy, aluminum, and aluminum alloy are used for the flow path plate. In addition to the metal plate, a green sheet in which glass powder is dispersed in a binder such as an acrylic resin to form a sheet may be used. The glass composition contained in the green sheet is selected so that it does not soften even under the heat treatment conditions during the annealing treatment described later.

  In the stacking step (step S14), the plates formed in step S10 are stacked to form a flow path plate. In an aspect in which a metal plate is used as the plate constituting the flow path plate, the bonding surfaces (boundary surfaces) of the plates are bonded by diffusion bonding, and the flow path plate and the diaphragm 56 are bonded by diffusion bonding (diffusion). Joining step, step S16).

  In the diffusion bonding step, the laminate is pressurized at a predetermined pressure for a predetermined time while being heated to a temperature higher than the recrystallization temperature (1000 ° C. to 1300 ° C.) of the laminate in a vacuum or an inert gas (nitrogen or argon) atmosphere. . An example of the pressure condition for diffusion bonding is 4.9 MPa to 19.6 MPa, and an example of the time condition is 0.5 hour to 24 hours.

  In the metal film forming step (step S22), TiAlN (or TiCrAlN) is formed over the entire surface of the diaphragm 56 opposite to the surface to which the flow path plate is bonded. A film forming method such as an AD method, an ion plating method, a sol-gel method, a sputtering method, or a screen printing method is applied to the metal film forming step.

  In the AD method, the substrate and the nozzle are relatively moved while spraying submicron diameter metal fine particles (aerosol) placed on nitrogen gas or the like from the aerosol nozzle to the substrate placed in the chamber. This is a film forming method for crystallizing at a predetermined position on the substrate surface.

  In the lower electrode film forming step (step S24), a metal thin film such as platinum or gold to be the lower electrode 57A (see FIG. 4) is formed on the metal film formed in the metal film forming step. A film forming method such as an AD method, an ion plating method, a sol-gel method, a sputtering method, or a screen printing method is applied to the lower electrode film forming step. The lower electrode is formed over the entire surface of the diaphragm 56 and serves as a common electrode for the piezoelectric elements 58. Of course, an individual lower electrode corresponding to each piezoelectric element 58 may be formed.

  In the piezoelectric film forming step (step S26), a piezoelectric body (piezoelectric film) 58A is formed on the lower electrode film. A film forming method such as an AD method, an ion plating method, a sol-gel method, a sputtering method, or a screen printing method is applied to the piezoelectric film forming step. The piezoelectric body 58A formed in step S26 may be formed individually corresponding to each pressure chamber, or may be formed over the entire surface of the diaphragm 56 in the same manner as the lower electrode 57A.

  Note that the same method may be used as a film forming method applied to the metal film forming step (step S22), the lower electrode forming step (step S24), and the piezoelectric film forming step (step S26).

  In the annealing step (step S28), annealing is performed under a temperature condition of 600 ° C to 1200 ° C. In the annealing process, the piezoelectric body 58A formed in step S26 is fired, and the metal film formed in step S22 is oxidized to form a metal oxide film (protective film) between the diaphragm 56 and the lower electrode 57A. 59) is formed.

When TiAlN is used for the metal film, the metal oxide film contains alumina (Al ₂ O ₃ ) and titania (TiO ₂ ). When TiCrAlN is used, the metal oxide film is chromium oxide in addition to alumina and titania. (CrO ₂ ) is contained. Due to the presence of the protective film 59, diffusion of iron contained in the diaphragm 56 into the piezoelectric body 58A is prevented.

  In step S30 (upper electrode film forming process), a metal thin film such as platinum or gold that functions as the upper electrode 57 is formed on the piezoelectric body 58A subjected to the annealing process in step S28 by the AD method or the screen printing method. The

  In step S32 (polarization step), a wiring member such as a flexible substrate is connected to the upper electrode 57 and the lower electrode 57A, and a predetermined voltage is applied between the upper electrode 57 and the lower electrode 57A, so that the piezoelectric body 58A is polarized. Is done. In the polarization step of this example, polarization processing is performed in the thickness direction of the piezoelectric body 58A (substantially perpendicular to the surface of the diaphragm 56). As the applied voltage at the time of the polarization treatment, a voltage higher than the drive voltage at the time of driving the piezoelectric element 58 is applied.

  Through the polarization process shown in step S32, the portion where the upper electrode 57 of the piezoelectric body 58A is formed becomes a piezoelectric active portion, and functions as a piezoelectric element that applies ejection force to the ink in the pressure chamber corresponding to each piezoelectric active portion.

  In step S34, the nozzle plate is joined to the flow path plate to which the diaphragm 56 and the piezoelectric element 58 are joined, and the head 50 is completed. The head 50 is incorporated into the main body of the inkjet recording apparatus 10 through a predetermined inspection (step S36).

  A resin material having low heat resistance can be used for the portion not subjected to the annealing process in step S28, and a joining member and a joining method are appropriately selected depending on the material.

  The manufacturing process shown in FIG. 6 is merely an example, and processes such as a heat treatment process and a pressurization process are performed depending on the film forming method applied to the lower electrode film forming process, the piezoelectric film forming process, and the upper electrode film forming process. As appropriate.

  The head 50 configured as described above is annealed in a state where a metal thin film such as TiAlN or TiCrAlN is formed between the diaphragm 56 and the piezoelectric element 58 (the lower electrode 57A and the piezoelectric body 58A). Therefore, a protective film 59 is formed between the diaphragm 56 and the piezoelectric element 58, and diffusion of iron contained in the diaphragm 56 into the piezoelectric element 58 is prevented.

In this example, a metal substrate containing iron such as stainless steel is exemplified. However, there is a possibility that the performance of PZT may be deteriorated due to diffusion of different elements even in a glass or silicon substrate [another embodiment].
Next, another embodiment of the present invention will be described. FIG. 7 shows another aspect of the head manufacturing process shown in FIG. In the head manufacturing process (step S10 ′) shown in FIG. 7, a pre-annealing process (first heat treatment process) is performed on the vibration plate 56 on which the TiAlN film has been formed in the metal film formation step (step S22). After forming the protective film 59 on the surface (step S23), the lower electrode is formed on the diaphragm 56 on which the protective film 59 is generated by the lower electrode film forming process (step S24) and the piezoelectric film forming process (step S26). 57A and the piezoelectric body 58A may be formed, and the piezoelectric body 58A may be fired by an annealing process (second heat treatment process).

  Further, as shown in FIG. 8, a protective film (first protective film) is formed on the surface (first surface) of the diaphragm 56 on which the piezoelectric element 58 is disposed, and the pressure of the diaphragm 56 is increased. A protective film (second protective film) 59A may be formed on the surface (second surface) on the chamber 52 side. The protective film 59A functions as an ink resistant film for the diaphragm 56. The protective film 59A may be formed over the entire surface of the diaphragm 56, or the protective film 59A may be formed only in the corresponding region of the pressure chamber 52.

  In the present embodiment, an ink jet recording apparatus that forms a desired image by ejecting ink onto the recording paper 16 has been described. However, the present invention describes a liquid that ejects liquid (treatment liquid, chemical liquid, water, etc.) onto a medium. The present invention can also be applied to a discharge device.

1 is an overall configuration diagram of an ink jet recording apparatus equipped with a head according to the present invention. FIG. 1 is a plan view of a main part around a printing unit of the ink jet recording apparatus shown in FIG. Plane perspective view showing structural example of head Sectional view along line 4-4 in FIG. 1 is a principal block diagram showing the system configuration of the ink jet recording apparatus shown in FIG. The figure explaining the manufacturing process of the head which concerns on embodiment of this invention. The figure explaining the other aspect of the manufacturing process of the head shown in FIG. The figure which shows the other aspect of the head shown in FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Inkjet recording device 50 ... Head, 51 ... Nozzle, 52 ... Pressure chamber, 56 ... Diaphragm, 57 ... Upper electrode, 57A ... Lower electrode, 58 ... Piezoelectric element, 58A ... Piezoelectric body, 59, 59A ... Protective film

Claims (8)

A thin film forming step for forming a thin film on both sides of the diaphragm containing iron;
A lower electrode film forming step of forming a lower electrode on one surface of the diaphragm on which the thin film is formed;
A piezoelectric film forming step of forming a piezoelectric film on the lower electrode;
An upper electrode film forming step of forming an upper electrode on the piezoelectric body;
A step of bonding a flow path plate to the other surface of the diaphragm on which the thin film is formed after the thin film forming step ;
The thin film, the lower electrode, and the piezoelectric body are formed on the one surface, the thin film is formed on the other surface, and the diaphragm, to which the flow path plate is bonded, is subjected to a heat treatment, and A heat treatment step of producing an oxide film obtained by oxidizing a thin film and firing the piezoelectric body;
Bonding a nozzle plate formed with a nozzle communicating with a liquid chamber formed in the flow path plate corresponding to the piezoelectric body on the opposite side of the vibration plate of the flow path plate;
A method for manufacturing a liquid discharge head, comprising: A thin film forming step for forming a thin film on both sides of the diaphragm containing iron;
A first heat treatment step of generating an oxide film obtained by performing heat treatment on the diaphragm on which the thin film is formed to oxidize the thin film;
A lower electrode film forming step of forming a lower electrode on one surface of the diaphragm on which the oxide film is generated;
A piezoelectric film forming step of forming a piezoelectric film on the lower electrode;
An upper electrode film forming step of forming an upper electrode on the piezoelectric body;
After the first heat treatment step , bonding a flow path plate to the other surface of the diaphragm on which the oxide film is formed;
The oxide film is formed on the one surface and the lower electrode and the piezoelectric body are formed, and the oxide film is formed on the other surface and the diaphragm plate is joined to the vibration plate. A second heat treatment step of firing the piezoelectric body by applying a heat treatment;
Bonding a nozzle plate formed with a nozzle communicating with a liquid chamber formed in the flow path plate corresponding to the piezoelectric body on the opposite side of the vibration plate of the flow path plate;
A method for manufacturing a liquid discharge head, comprising:   The method of manufacturing a liquid discharge head according to claim 1, wherein the thin film contains titanium and aluminum. A liquid chamber forming step for forming a liquid chamber for storing a liquid to which a discharge force is applied from the piezoelectric body;
A nozzle forming step of communicating with the liquid chamber and forming a nozzle for discharging the liquid;
The method of manufacturing a liquid discharge head according to claim 1, wherein Step of bonding the flow path plate, a manufacturing method of a liquid discharge head according to claim 1, any one of 4, which is a diffusion bonding process.   The method of manufacturing a liquid ejection head according to claim 5, wherein the diffusion bonding step is performed in a vacuum environment or an inert gas environment.   The method of manufacturing a liquid discharge head according to claim 5, wherein the diffusion bonding step is performed while heating to a temperature equal to or higher than a recrystallization temperature of the vibration plate and the flow path plate.   8. The method of manufacturing a liquid ejection head according to claim 5, wherein the diffusion bonding step is performed under a pressure condition of 4.9 megapascals or more and 19.6 megapascals or less.

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