JP2006224401A - Liquid discharging head, image forming device equipped with it, and manufacturing method for liquid discharging head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make a discharging port denser by devising the wiring structure to the electrode of a driving element for discharging a liquid, and at the same time, to facilitate the manufacture of a liquid discharging head. <P>SOLUTION: This liquid discharging head has a pressure generating means, a common liquid chamber, and a wiring member. In this case, the pressure generating means is provided on a surface on the opposite side from the discharging port of a pressure chamber communicating with the discharging port which discharges the liquid, and deforms the pressure chamber. The common liquid chamber is arranged on the opposite side from the pressure chamber regarding the pressure generating means, and feeds the liquid to the pressure chamber. The wiring member is approximately vertically erected to the surface on which the pressure generating means is formed by penetrating the inside of the common liquid chamber. The arrangement pitch of the wiring member is arranged to become smaller than the arrangement pitch of an electrode connecting section of the pressure generating means. Then, a driving signal is fed to the pressure generating means by the wiring member which electrically connects the electrode connecting section of the pressure generating means and an upper wiring layer which is provided on the opposite side from the pressure chamber of the common liquid chamber. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a liquid discharge head, an image forming apparatus including the same, and a method for manufacturing the liquid discharge head, and in particular, the density of discharge ports for discharging liquid is increased and wiring connection at the time of manufacturing is highly accurate. The present invention relates to a liquid discharge head that does not require alignment and facilitates shape formation, an image forming apparatus including the same, and a method for manufacturing the liquid discharge head.

  2. Description of the Related Art Conventionally, an image forming apparatus has an inkjet head (liquid ejection head) in which a large number of nozzles (ejection ports) are arranged, and the inkjet head and the recording medium are moved relative to each other while the inkjet head and the recording medium are moved relative to each other. Inkjet printers (inkjet recording apparatuses) are known that record an image on a recording medium by ejecting ink toward the recording medium.

  Such an ink jet printer supplies ink to a pressure chamber from an ink tank via an ink supply path, applies an electrical signal corresponding to image data to the piezoelectric element, and drives the piezoelectric element, thereby The diaphragm constituting the portion is deformed to reduce the volume of the pressure chamber, and the ink in the pressure chamber is ejected as droplets from the nozzle.

  As described above, in an ink jet printer, ink is ejected from a nozzle onto a recording medium to form dots, and by combining these dots, one image is formed on the recording medium. In recent years, it has been desired to form high-quality images that are comparable to photographic prints in inkjet printers. On the other hand, it is possible to achieve high image quality by reducing the nozzle diameter to reduce the ink droplets ejected from the nozzle and increasing the number of pixels per image by arranging the nozzles at high density. It is considered. As a method for increasing the density of such a nozzle arrangement, it has been conventionally proposed to arrange the nozzles in a two-dimensional matrix.

  For example, a plurality of nozzles are arranged in a grid formed by a plurality of rows inclined at a certain angle with respect to the head main scanning direction and a plurality of columns orthogonal to the head main scanning direction, and provided corresponding to each nozzle. It is known that the planar shape of the vibration plate forming one surface of the pressure chamber is approximately square or rhombus, thereby improving the discharge efficiency of the pressure chamber and arranging the nozzles at high density. (For example, refer patent document 1 etc.).

In addition, a pressure chamber provided in the cavity plate is formed in a substantially rhombus shape, an ink supply port is formed in one acute angle portion of the pressure chamber, and an ink ejection nozzle is formed in the other acute angle portion. It is known that a large number of ink pressure chambers corresponding to multiple nozzles are arranged without increasing the size of the tee plate so as to increase the density of the nozzles (for example, Patent Document 2). reference).
JP 2001-334661 A JP 2002-166543 A

  However, when the nozzles are arranged two-dimensionally in the configuration of the ink jet head described in the above-mentioned patent documents and the like and the nozzle density is increased, the driving elements corresponding to the nozzles are also arranged two-dimensionally. Therefore, it is necessary to arrange the wiring to the electrode of the driving element in a two-dimensional manner, and there is a problem that it is difficult to actually manufacture an ink jet head having a high density of nozzles with such a configuration.

  The present invention has been made in view of such circumstances, and devised the wiring structure to the electrodes of the drive elements for discharging the liquid to increase the density of the discharge ports (nozzles) and to manufacture An object of the present invention is to provide a liquid discharge head that can easily form a shape without requiring highly accurate alignment of wiring connections at the time, an image forming apparatus including the liquid discharge head, and a method of manufacturing the liquid discharge head.

  In order to achieve the object, the invention according to claim 1 is provided in a pressure chamber communicating with a discharge port for discharging a liquid, and on a surface of the pressure chamber opposite to the discharge port, A pressure generating means for deforming a chamber, and the pressure generating means, disposed on the opposite side of the pressure chamber, passing through the common liquid chamber, a common liquid chamber for supplying the liquid to the pressure chamber, A wiring member erected substantially perpendicular to the surface on which the pressure generating means is formed, and the wiring member has an arrangement pitch that is greater than an arrangement pitch of electrode connection portions of the pressure generating means. The wiring member that is arranged so as to be small and electrically connects between the electrode connecting portion of the pressure generating means and the upper wiring layer provided on the opposite side of the pressure chamber of the common liquid chamber. That the drive signal is supplied to the pressure generator. To provide a liquid discharge head according to symptoms.

  Thereby, when forming the wiring member, it is not necessary to precisely control the position where the wiring member is arranged, and the formation of the wiring member is facilitated. In addition, when joining the wiring member to the electrode connection part, it is not necessary to perform precise positioning, so it is necessary to take into account the positional deviation caused by the thermal expansion of the wiring member and pressure generating means due to heating and pressurization at the time of joining. It becomes easy to join. Further, in forming the shape on the wiring member, it is not necessary to consider the relationship between the position of forming the shape and the position of the wiring, so that the forming of the shape is facilitated.

  According to a second aspect of the present invention, the wiring member has a structure in which a conductive material passes through a substrate material made of an insulating material.

  Thereby, a wiring member can be formed easily.

  According to a third aspect of the present invention, the common liquid chamber is constituted by a hollow portion formed in the substrate material on which the wiring member is formed.

  This facilitates the formation of a liquid flow path, and can easily form a wiring member that penetrates the common liquid chamber substantially vertically.

  According to a fourth aspect of the present invention, there is provided a pressure chamber that communicates with a discharge port for discharging a liquid, and a pressure generating means that is provided on a surface of the pressure chamber opposite to the discharge port and that deforms the pressure chamber. And the pressure generating means is disposed on the opposite side of the pressure chamber, the common liquid chamber supplying the liquid to the pressure chamber, and the pressure generating means are formed through the common liquid chamber. A wiring member erected substantially perpendicular to the surface to be connected, and the arrangement density of the wiring members is set so that the electrode connecting portion of the pressure generating means and at least one of the wiring members can be connected. A liquid discharge head is provided.

  Thereby, when joining a wiring member, exact positioning becomes unnecessary and manufacture becomes easy.

  Similarly, in order to achieve the object, an invention according to claim 5 provides an image forming apparatus having the liquid discharge head according to any one of claims 1 to 4.

  This facilitates manufacture of the image forming apparatus, ensures electrical connection in the liquid discharge head, and improves image quality.

  Similarly, in order to achieve the object, the invention according to claim 6 is a wiring member for supplying a drive signal to a pressure generating means for deforming a pressure chamber having a discharge port for discharging a liquid, and the pressure generation. According to another aspect of the invention, there is provided a method of manufacturing a liquid discharge head, wherein the wiring member is arranged at a pitch smaller than an arrangement pitch of the electrode connecting portions when electrically connecting the electrode connecting portions.

  This eliminates the need for precise alignment when bonding the wiring member to the electrode connection portion, and therefore considers misalignment due to thermal expansion of the wiring member and pressure generating means due to heating and pressurization during bonding. There is no need, and joining becomes easy.

  Similarly, in order to achieve the object, the invention according to claim 7 is a wiring member for supplying a drive signal to a pressure generating means for deforming a pressure chamber having a discharge port for discharging a liquid, and the pressure generation. A method of manufacturing a liquid ejection head, wherein the arrangement density of the wiring members is set so that at least one of the wiring members is connected to the electrode connection portion when electrically connecting to the electrode connection portion of the means I will provide a.

  Thereby, when joining a wiring member to an electrode connection part, it is not necessary to perform precise alignment and a liquid discharge head can be manufactured easily.

  As described above, according to the liquid ejection head, the image forming apparatus including the liquid ejection head, and the method for manufacturing the liquid ejection head according to the present invention, when the wiring member is formed, the position at which the wiring member is precisely arranged is controlled. There is no need, and patterning of the wiring becomes unnecessary, and the formation of the wiring member is facilitated. In addition, when joining the wiring member to the electrode connection part, it is not necessary to perform precise positioning, so it is necessary to take into account the positional deviation caused by the thermal expansion of the wiring member and pressure generating means due to heating and pressurization at the time of joining. It becomes easy to join. Further, in forming the shape on the wiring member, it is not necessary to consider the relationship between the position of forming the shape and the position of the wiring, so that the forming of the shape is facilitated.

  Hereinafter, a liquid discharge head according to the present invention, an image forming apparatus including the liquid discharge head, and a method of manufacturing the liquid discharge head will be described in detail with reference to the accompanying drawings.

  FIG. 1 is an overall configuration diagram showing an outline of an embodiment of an ink jet recording apparatus as an image forming apparatus having a liquid ejection head according to the present invention.

  As shown in FIG. 1, the inkjet recording apparatus 10 includes a printing unit 12 having a plurality of printing heads (liquid ejection 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 that stores ink to be supplied, a paper feeding unit 18 that supplies recording paper 16, a decurling unit 20 that removes curling of the recording paper 16, and the printing The suction belt conveyance unit 22 that is arranged to face the nozzle surface (ink ejection surface) of the unit 12 and conveys the recording paper 16 while maintaining the flatness of the recording paper 16, and the print detection that reads the printing result by the printing unit 12 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 wider 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).

  As shown in FIG. 2, each of the print heads 12K, 12C, 12M, and 12Y has a plurality of ink discharge ports (nozzles) over a length that exceeds at least one side of the maximum size recording paper 16 targeted by the inkjet recording apparatus 10. It is composed of arranged line type heads.

  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.

  Here, the main scanning direction and the sub-scanning direction are used in the following meaning. That is, when driving the nozzles with a full line head having a nozzle row corresponding to the full width of the recording paper, (1) whether all the nozzles are driven simultaneously or (2) whether the nozzles are driven sequentially from one side to the other (3) The nozzles are divided into blocks, and each nozzle is driven sequentially from one side to the other for each block, and the width direction of the paper (perpendicular to the conveyance direction of the recording paper) Nozzle driving that prints one line (a line made up of a single row of dots or a line made up of a plurality of rows of dots) in the direction of scanning is defined as main scanning. A direction indicated by one line (longitudinal direction of the belt-like region) recorded by the main scanning is called a main scanning direction.

  On the other hand, by relatively moving the above-described full line head and the recording paper, printing of one line (a line formed by one line of dots or a line composed of a plurality of lines) formed by the above-described main scanning is repeatedly performed. Is defined as sub-scanning. A direction in which sub-scanning is performed is referred to as a sub-scanning direction. After all, the conveyance direction of the recording paper is the sub-scanning direction, and the direction orthogonal to it is the main scanning direction.

  Further, 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 a selecting means (not shown) for switching the paper discharge path in order to select the printed matter of the main image and the printed matter of the test print and send them to the respective discharge portions 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.

  Next, the arrangement of the nozzles (liquid ejection ports) of the print head (liquid ejection head) will be described. Since the structures of the print heads 12K, 12C, 12M, and 12Y provided for each ink color are common, the print head is represented by the reference numeral 50 in the following, and the print head 50 is shown in FIG. The plane perspective view of is shown.

  As shown in FIG. 3, the print head 50 of this embodiment includes a nozzle 51 that ejects ink as droplets, a pressure chamber 52 that applies pressure to ink when ejecting ink, and a common flow that is not shown in FIG. The pressure chamber units 54 each including an ink supply port 53 for supplying ink from the passage to the pressure chamber 52 are arranged in a staggered two-dimensional matrix so as to increase the density of the nozzles 51.

  The size of the nozzle arrangement on the print head 50 is not particularly limited. As an example, the nozzle 51 is arranged in 48 rows (21 mm) and 600 columns (305 mm) in length to achieve 2400 npi. .

  In the example shown in FIG. 3, when each pressure chamber 52 is viewed from above, the planar shape thereof is substantially square, but the planar shape of the pressure chamber 52 is not limited to such a square. Absent. In the pressure chamber 52, as shown in FIG. 3, a nozzle 51 is formed at one end of the diagonal line, and an ink supply port 53 is provided at the other end.

  FIG. 4 is a perspective plan view showing another structural example of the print head. As shown in FIG. 4, a plurality of short heads 50 'are arranged and connected in a two-dimensional staggered pattern so that the entire length of the plurality of short heads 50' corresponds to the entire width of the print medium. One long full line head may be configured.

  FIG. 5 is a perspective perspective view showing a part of the print head 50 in a simplified manner.

  As shown in FIG. 5, in the print head 50 of the present embodiment, a diaphragm 56 that forms the upper surface of the pressure chamber 52 is disposed above the pressure chamber 52 having the nozzle 51 and the ink supply port 53, and the diaphragm A piezoelectric element 58 (piezoelectric actuator) as a pressure generating means composed of a piezoelectric body such as a piezo sandwiched between electrodes is disposed in a portion corresponding to each pressure chamber 52 on 56, and the piezoelectric element 58 is disposed on the upper surface thereof. Individual electrodes 57 are provided.

  An electrode pad 59 as an electrode connecting portion is formed to be extended from the end face of the individual electrode 57 to the outside, and the electric wiring 90 is substantially perpendicular to the surface including the piezoelectric element 58 (pressure generating means) on the electrode pad 59. Standing up and formed. A multilayer flexible cable 92 is disposed on the electrical wiring 90 that rises substantially perpendicular to the surface including the piezoelectric element 58, and a driving signal is transmitted from the head driver 84 to the piezoelectric element 58 via these wirings. It is supplied to the individual electrode 57.

  A space in which columnar electric wires 90 are arranged between the diaphragm 56 and the multilayer flexible cable 92 is arranged in a common liquid chamber 55 for supplying ink to the pressure chambers 52 through the ink supply ports 53. It has become.

  The common liquid chamber 55 shown here is one large space formed over the entire region where the pressure chambers 52 are formed so as to supply ink to all the pressure chambers 52 shown in FIG. However, the common liquid chamber 55 is not limited to the one formed as a single space as described above, and may be divided into several regions and formed in a plurality.

  The electric wiring 90 formed by standing up like a pillar vertically on the electrode pad 59 provided by being drawn out from the individual electrode 57 for each pressure chamber 52 supports the multilayer flexible cable 92 from below, and the common liquid chamber 55. To form a space. Thus, the columnar electric wiring 90 is formed so as to penetrate the common liquid chamber 55.

  As shown in FIG. 5, the nozzle 51 is formed on the bottom surface side of the pressure chamber 52, and the ink supply port 53 is provided on the upper surface side of the corner of the pressure chamber 52 that forms a diagonal with the nozzle 51. The ink supply port 53 passes through the vibration plate 56, and the common liquid chamber 55 and the pressure chamber 52 thereabove communicate with each other through the ink supply port 53. Thereby, the common liquid chamber 55 and the pressure chamber 52 can be directly connected fluidically.

  The diaphragm 56 is common to the pressure chambers 52 and is formed of a single plate. In addition, piezoelectric elements 58 for deforming the pressure chambers 52 are arranged at portions corresponding to the pressure chambers 52 of the diaphragm 56. Electrodes (common electrode and individual electrode) for applying a voltage to the piezoelectric element 58 for driving are formed on the upper and lower surfaces so as to sandwich the piezoelectric element 58.

  For example, the diaphragm 56 may be formed of a conductive thin film such as SUS, and the diaphragm 56 may also serve as a common electrode. At this time, individual electrodes 57 for individually driving the piezoelectric elements 58 are formed on the upper surface of the piezoelectric elements 58.

  As described above, the electrode pad 59 is drawn out from the individual electrode 57, and the columnar electric wiring 90 rises perpendicularly to the surface on which the piezoelectric element 58 is formed on the electrode pad 59. It is formed so as to penetrate the liquid chamber 55. In the example shown in FIG. 5, the electrical wiring 90 is formed in a taper shape such that the upper multilayer flexible cable 92 side is thicker and becomes thinner toward the lower electrode pad 59 side, but is limited to such a shape. It is not something.

  Thus, the multilayer flexible cable 92 is formed on the columnar electric wiring 90, and the electric wiring 90 serves as a column to support the multilayer flexible cable 92, the diaphragm 56 as a floor, and the multilayer flexible cable 92 as a ceiling. As a result, a space as the common liquid chamber 55 is secured. Although not shown, each electric wiring 90 is connected to an individual wiring and a driving signal is supplied to each individual electrode 57 to drive each piezoelectric element 58.

  Although not shown in FIG. 5, since the common liquid chamber 55 is filled with ink, the surfaces of the diaphragm 56, the individual electrode 57, the electric wiring 90, and the multilayer flexible cable 92 that are in contact with the ink as the common electrode are respectively shown. It is covered with an insulating protective film.

  Each size of the print head 50 as described above is not particularly limited, but as an example, the pressure chamber 52 has a substantially square shape with a plane shape of 300 μm × 300 μm (excludes the stagnation point of the ink flow). The corners are chamfered for the purpose.) The height is 150 μm, the diaphragm 56 and the piezoelectric element 58 are each 10 μm thick, and the columnar electric wiring 90 is 100 μm in diameter at the connection with the electrode pad 59. The thickness is formed to 500 μm or the like.

  FIG. 6 is an enlarged plan view of a part of such a pressure chamber 52. As described above, each pressure chamber 52 has a substantially square shape. The nozzle 51 and the ink supply port 53 are formed at both corners of the diagonal line, the electrode pad 59 is drawn out to the nozzle 51 side, and a columnar electric chamber is formed thereon. A wiring 90 is formed.

  FIG. 7 is a cross-sectional view taken along the alternate long and short dash line 7-7 in FIG.

  As shown in FIG. 7, the print head 50 of this embodiment is formed by laminating a plurality of thin films and the like. First, a flow path plate 96 in which a pressure chamber 52, an ink supply port 53, a nozzle flow path 51a connecting the pressure chamber 52 and the nozzle 51, and the like are formed is laminated on the nozzle plate 94 in which the nozzle 51 is formed. In the figure, the flow path plate 96 is represented as a single plate, but in actuality, the flow path plate 96 is formed by laminating a plurality of plates.

  A diaphragm 56 that forms the top surface of the pressure chamber 52 is stacked on the flow path plate 96. It is preferable that the diaphragm 56 also serves as a common electrode for driving a piezoelectric element 58 described later together with the individual electrode 57. The diaphragm 56 is provided with an opening corresponding to the ink supply port 53 of the pressure chamber 52, whereby the pressure chamber 52 and the common liquid chamber 55 formed on the upper side of the diaphragm 56 communicate directly.

  A piezoelectric body 58a is formed on a portion corresponding to substantially the entire upper surface of the pressure chamber 52 on the diaphragm 56 (common electrode), and an individual electrode 57 is formed on the upper surface of the piezoelectric body 58a. Thus, the piezoelectric body 58a sandwiched between the common electrode (the diaphragm 56) and the individual electrode 57 is deformed when a voltage is applied between the common electrode 56 and the individual electrode 57, and the volume of the pressure chamber 52 is increased. A piezoelectric element 58 (piezoelectric actuator) that discharges ink from the nozzle 51 is configured.

  The end of the individual electrode 57 on the nozzle 51 side is drawn outward to form an electrode pad 59 as an electrode connection portion. A columnar electric wiring 90 is vertically formed on the electrode pad 59 so as to penetrate the common liquid chamber 55.

  A multilayer flexible cable 92 is formed above the electrical wiring 90, and each wiring (not shown) formed on the multilayer flexible cable 92 is connected to each electrical wiring 90 by an electrode pad 90a to drive each piezoelectric element 58. A driving signal for supplying the signal is supplied through each electric wiring 90.

  A space where the columnar electric wiring 90 between the diaphragm 56 and the multilayer flexible cable 92 stands is a common liquid chamber 55 for pooling ink to be supplied to the pressure chamber 52. In order to fill, an insulating / protective film 98 is formed on the surface portion of the diaphragm 56, the individual electrode 57, the piezoelectric body 58 a and the electrical wiring 90, and the surface of the multilayer flexible cable 92 that contacts the ink.

  As described above, in the present embodiment, the common liquid chamber that has conventionally been on the same side as the pressure chamber with respect to the diaphragm is brought to the upper side of the diaphragm, and arranged on the side opposite to the pressure chamber. Piping for guiding ink from the common liquid chamber to the pressure chamber, which was necessary in the past, is no longer necessary, and the size of the common liquid chamber can be increased, so that ink can be supplied reliably and the high density of the nozzle Can be achieved, and high-frequency driving is possible even when the density is increased.

  In addition, the wiring to the individual electrodes of each piezoelectric element is set up vertically from the electrode pad of the individual electrode so as to penetrate the common liquid chamber, so that the wiring for supplying the drive signal to each piezoelectric element is densified. It becomes possible to do.

  In addition, since the common liquid chamber is arranged on the upper side of the diaphragm so that the common liquid chamber and the pressure chamber are connected by a straight ink supply port, the common liquid chamber and the pressure chamber can be directly connected fluidically. Furthermore, since the common liquid chamber is disposed on the upper side of the diaphragm, the length of the nozzle channel 51a from the pressure chamber 52 to the nozzle 51 can be made shorter than before, and even when the density is increased, Viscosity ink (for example, about 20 cp to 50 cp) can be discharged, and a flow path structure capable of quick refilling after discharge can be obtained.

  The present invention electrically connects between the electrode pad 59 drawn out from the individual electrode 57 of the piezoelectric element 58 provided for each pressure chamber 52 and the multilayer flexible cable 92 as shown in FIG. In forming the columnar electric wiring 90 to be connected, the arrangement of the electric wiring 90 is devised so that the electric wiring 90 and the electrode pad 59 can be easily connected without requiring precise alignment. It is.

  Note that the columnar electric wires 90 that electrically connect the electrode pads 59 and the multilayer flexible cable 92 shown in FIGS. 5 to 7 are in an ideally arranged state. In this forming process, the position may be slightly different from those shown in these drawings, but anyway, it is intended to easily ensure electrical connection.

  Hereinafter, an arrangement method of the electric wiring 90 in the step of forming the electric wiring 90 will be described.

  FIG. 8 shows a plan view of the electrode pads 59 arranged two-dimensionally. As shown in FIG. 8, the electrode pads 59 are two-dimensionally arranged at an equal pitch like the pressure chambers 52. The shape of the electrode pad 59 is not particularly limited, but in this example, as shown in FIG. 8, the electrode pad 59 is circular, the diameter is d, and the pitch between the electrode pads 59 is a.

  On the other hand, the arrangement of the wiring members to be the electrical wiring 90 is shown in FIG. FIG. 9A is a plan view showing a state in which a plurality of wiring members 100 are arranged for one electrode pad 59. Further, FIG. 9B shows a cross-sectional view taken along line 9B-9B in FIG.

  The wiring member 100 is formed in a column shape by a conductive member as shown in FIG. 9B in the substrate material 102 for forming the wiring member 100. The pitch between the wiring members 100 in the arrangement of the wiring members 100 may be equal pitch, or may not be equal pitch as shown in FIG. However, even when they are arranged at an equal pitch, the pitch is not equal to the pitch a of the electrode pads 59 and is smaller than the pitch a of the electrode pads 59.

  The material of the wiring member 100 is not particularly limited.

  For example, as the wiring member 100, a so-called anisotropic conductive rubber (anisotropic conductive material layer) in which a large number of thin conductive wires such as metals are embedded in an insulating material such as rubber or resin may be used. The wiring member 100 may be configured by making holes in the formed substrate material 102 and plating the inner wall of the holes or applying a conductive paste to make the holes conductive. .

  Next, a method for arranging the wiring member 100 will be described with reference to FIG.

  The electrical wiring 90 electrically connects between the electrode pad 90 a (see FIG. 7) on the multilayer flexible cable 92 side and the electrode pad 59 on the piezoelectric element 58 side, and the wiring member 100 that becomes the electrical wiring 90. In any case, the electrode pad 90a and the electrode pad 59 may be electrically connected anyway, and the shape, number, etc. thereof are not limited. Therefore, for example, at least one wiring member 100 may be arranged in a circle representing the electrode pad 59 shown in FIG.

  Further, basically, the wiring member 100 is aimed to be arranged at an equal pitch smaller than the pitch a of the electrode pads 59.

  In FIG. 10, a broken-line circle represents one electrode pad 59. A dot-and-dash lattice point represents a target position (average position) where the wiring member 100 is arranged as a design target, and a design pitch (average pitch) of the wiring member 100 is x. The solid line circle 104 is a circle centered at a target position (a dot-and-dash line grid point) where the wiring member 100 is disposed, and represents a range in which the actually disposed wiring member 100 is displaced from the target position. Represents. Accordingly, the radius r represents the maximum deviation (deviation) from the target position.

  As described above, at least one of the actual wiring members 100 must be arranged in each solid-line circle 104 even if the actual wiring member 100 deviates from the dot-and-dash line grid point that is the target position. In order for the circle representing at least one wiring member 100 to overlap the circle representing each electrode pad 59, the maximum of the distances between the two wiring members 100 vertically, horizontally, and diagonally adjacent is the electrode pad 59. What is necessary is just to be smaller than the diameter d.

  The wiring member 100 represented by a black circle in FIG. 10 is a case where the wiring member 100 is arranged at the position most deviated from the target position, and shows the one having the maximum distance among the adjacent ones. In FIG. 10, the distance between the wiring members 100 farthest among the adjacent ones is (√2) x + 2r. When this is larger than the diameter d of the electrode pad 59, when the wiring member 100 is arranged at such a position for each of the four solid circles 104 shown in FIG. 10, the circle of each wiring member 100 corresponds to the electrode pad 59. And the wiring member 100 may not be disposed on the electrode pad 59.

  Therefore, the wiring member 100 is arranged so that the following relational expression (1) holds among the average pitch x of the wiring member 100, the maximum value r of the deviation from the average position of the wiring member 100, and the diameter d of the electrode pad 59. It shall be.

(√2) x + 2r <d (1)
If the wiring member 100 is arranged such that the diameter d of the electrode pad 59, the maximum deviation r when placing, and the average pitch x of the wiring member 100 satisfy the above formula (1), the wiring member 100 is arranged. When connecting the electrode pads 59 to each other, it is possible to arrange the electrode pads 59 so that at least one wiring member 100 is connected to each electrode pad 59 without precise alignment. It becomes.

  In addition, in this way, in the bonding process of the wiring member 100 to the electrode pad 59, it is not necessary to perform precise alignment, so the position due to thermal expansion on the wiring member 100 or the piezoelectric element 58 side due to heating / pressurization at the time of bonding. There is no need to consider the deviation, the joining is easy, and the yield can be improved.

  Furthermore, since it is not necessary to consider the relationship between the shape formation position and the wiring position in the shape forming step of the wiring member 100, the shape formation of the wiring member 100 is facilitated.

  Further, the wiring member 100 that is connected to the electrode pad 59 and becomes the electrical wiring 90 is formed so as to penetrate through the common liquid chamber 55 that supplies ink to the pressure chamber 52 as shown in FIG. Therefore, as shown in FIG. 9B, a concave portion (cavity) is formed in a portion corresponding to the member constituting the pressure chamber 52 with respect to the substrate material 102 (anisotropic conductive material layer) on which the wiring member 100 is formed. And the concave portion (hollow portion) serves as a common liquid chamber 55.

  FIG. 11 shows a state in which a recess is formed in the substrate material 102 on which the wiring member 100 is formed. As shown in FIG. 11, a portion corresponding to the member constituting the pressure chamber 52 is scraped away from the substrate material 102 on which the wiring member 100 is formed, thereby forming a recess 106. The method for forming the recess 106 is not particularly limited. For example, the substrate material 102 on which the wiring member 100 is formed may be formed as a recess 106 by forming a groove by performing vertical and horizontal half-cut processing using a dicer or the like.

  In order to form the common liquid chamber 55, at least a part of the recess 106 formed in the substrate material 102 on which the wiring member 100 is formed may be completely penetrated.

  Further, the step of cutting the substrate material 102 on which the wiring member 100 is formed in this way to form the recess 106 that becomes the common liquid chamber 55 may be performed at the stage where the wiring member 100 is formed on the substrate material 102. It may be performed after the upper wiring layer such as the multilayer flexible cable 92 is joined to the substrate material 102 on which the wiring material 100 is formed. In this case, the portion corresponding to the pressure chamber 52 of the substrate material 102 on which the wiring member 100 is formed may be completely removed until it penetrates to the upper wiring layer.

  Alternatively, after the substrate material 102 on which the wiring member 100 is formed is joined to the pressure chamber 52 and the member on the piezoelectric element 58 side, a portion corresponding to the pressure chamber 52 of the substrate material 102 on which the wiring member 100 is formed is laterally moved. You may make it scrape off by a drill or laser processing.

  In this manner, the substrate material 102 on which the wiring member 100 is formed leaves a portion of the wiring member 100 that has become the electric wiring 90, and a portion corresponding to the pressure chamber 52 around it is scraped to form a recess 106, Since this portion is used as the common liquid chamber 55, the electric wiring 90 (wiring member 100) is erected in a column shape substantially perpendicular to the surface of the electrode pad 59 and is formed so as to penetrate the common liquid chamber 55. . Note that when the substrate material 102 on which the wiring member 100 is formed is scraped off, the wiring member 100 may be exposed. Therefore, after joining the wiring member 100 and the member on the pressure chamber 52 side, the common liquid chamber inside the member is exposed. It is preferable to insulate the portion facing 55.

  Further, as another method of forming the recess 106 in the substrate material 102 on which the wiring member 100 is formed, for example, the recess is formed on the substrate material 102 on which the wiring member 100 is not yet formed, and the portions other than the recess are columnar. Then, the wiring member may be formed in a columnar portion other than the recess.

  That is, as shown in FIG. 12 (a), only the substrate material 102 having the recess 106 and the columnar portion 102a other than the recess is formed by first heat-molding the resin 108 with a mold. Then, as shown in FIG. 12B, a hole 110 is formed in the columnar portion 102a other than the recess 106 of the substrate material 102, and plating 112 is applied to the inner wall surface of the hole 110, or a conductive paste is poured. Thus, the wiring member 100 is formed by imparting conductivity to the hole 110 part. In this case, not only one wiring member 100 but also a plurality of wiring members 100 may be formed on each columnar portion 102 a of the substrate material 102.

  The print head 50 is formed by joining the multilayer flexible cable 92 and the member on the pressure chamber 52 side to the substrate material 102 on which the wiring member 100 is formed.

  At this time, by arranging the wiring member 100 so as to satisfy the above formula (1), the individual electrode pads 59 and the wiring member 100 can be joined without the need for precise alignment, and easily. The print head 50 can be formed.

  In the above example, the electrode pad 59 has been described as having a circular shape, but the shape is not necessarily limited to a circle. When the shape of the electrode pad 59 is not a circle, the maximum width of the electrode pad 59 is used as the diameter d used above.

  Next, another arrangement method of the wiring member will be described.

  In the wiring member arrangement method described below, the wiring members are not arranged at an equal pitch in design as in the above example, but the arrangement of the wiring members is defined by the arrangement density of the wiring members.

The design center value of the density (arrangement density) when the wiring members 100 are arranged is S [lines / m ² ]. On the other hand, the variation in the increasing direction is + s ₁ , and the variation in the decreasing direction is −s ₂ . That is, when the wiring member 100 is actually arranged, the number of the wiring members 100 arranged per unit area (1 m ² ) varies in the range from S−s ₂ (book) to S + s ₁ (book).

At this time, as shown in FIG. 13, when the electrode pad 59 is circular, the area of the electrode pad 59 is (πd ² ) / 4 [m ² ]. At this time, in order to arrange at least one wiring member 100 in the electrode pad 59, the following equation (2) is established using the density S−s ₂ [lines / m ² ] in the smallest case. It is necessary to.

{(Πd ² ) / 4} × (S−s ₂ ) ≧ 1 (2)
If this equation (2) is established, at least one wiring member 100 is arranged in the electrode pad 59. In the example shown in FIG. 13, two wiring members 100 are arranged in the electrode pad 59.

  In the example just described, it is only necessary to determine the arrangement density of the wiring members according to the area of the electrode pad, and it is possible to easily make electrical connection with the electrode without performing high-precision alignment in the manufacturing process. And shape formation is facilitated.

  Although the liquid ejection head, the image forming apparatus including the liquid ejection head, and the method for manufacturing the liquid ejection head have been described in detail above, the present invention is not limited to the above examples and does not depart from the gist of the present invention. It goes without saying that various improvements and modifications may be made in the range.

1 is an overall configuration diagram showing an outline of an embodiment of an ink jet recording apparatus as an image forming apparatus according to the present invention. FIG. 2 is a plan view of a main part around a printing unit of the inkjet recording apparatus shown in FIG. 1. FIG. 3 is a plan perspective view illustrating a structural example of a print head. It is a top view which shows the other example of a print head. FIG. 3 is an enlarged perspective view illustrating a part of the print head. FIG. 3 is an enlarged plan view showing a part of a print head. FIG. 7 is a cross-sectional view taken along line 7-7 in FIG. It is a top view which shows arrangement | positioning of an electrode pad. (A) is a top view which shows the example of arrangement | positioning of the wiring member with respect to an electrode pad, (b) is sectional drawing along the 9A-9B line | wire of (a). It is explanatory drawing which shows the arrangement | positioning method of a wiring member. It is sectional drawing which shows a mode that a recessed part is formed in the board | substrate material in which the wiring member was formed. (A), (b) is explanatory drawing which shows the other example which forms a recessed part in board | substrate material. It is explanatory drawing which shows the other arrangement | positioning method of a wiring member.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Inkjet recording device, 12 ... Printing part, 14 ... Ink storage / loading part, 16 ... Recording paper, 18 ... Paper feeding part, 20 ... Decal processing part, 22 ... Adsorption belt conveyance part, 24 ... Print detection part, 26 DESCRIPTION OF REFERENCE SYMBOLS: Paper discharge unit, 28 ... Cutter, 30 ... Heating drum, 31, 32 ... Roller, 33 ... Belt, 34 ... Adsorption chamber, 35 ... Fan, 36 ... Belt cleaning unit, 40 ... Heating fan, 42 ... Post-drying unit, 44 ... heating / pressurizing unit, 45 ... pressure roller, 48 ... cutter, 50 ... print head, 51 ... nozzle, 51a ... nozzle flow path, 52 ... pressure chamber, 53 ... ink supply port, 54 ... pressure chamber unit, 55 ... Common liquid chamber, 56 ... Diaphragm (common electrode), 57 ... Individual electrode, 58a ... Piezoelectric material, 58 ... Piezoelectric element, 59 ... Electrode pad, 90 ... Electric wiring, 92 ... Multi-layer flexible cable, 100 ... Arrangement Wire member, 102 ... substrate material, 106 ... recess (cavity)

Claims (7)

A pressure chamber communicating with a discharge port for discharging liquid;
A pressure generating means provided on a surface of the pressure chamber opposite to the discharge port, for deforming the pressure chamber;
Regarding the pressure generating means, a common liquid chamber that is disposed on the opposite side of the pressure chamber and supplies the liquid to the pressure chamber;
A wiring member penetrating through the common liquid chamber and erected substantially perpendicular to the surface on which the pressure generating means is formed,
The wiring member is arranged such that the arrangement pitch is smaller than the arrangement pitch of the electrode connecting portions of the pressure generating means, and the electrode connecting portions of the pressure generating means and the pressure chambers of the common liquid chamber A liquid discharge head characterized in that a drive signal is supplied to the pressure generating means by the wiring member electrically connected to the upper wiring layer provided on the opposite side.   The liquid ejection head according to claim 1, wherein the wiring member has a structure in which a conductive material penetrates a substrate material made of an insulating material.   The liquid ejection head according to claim 2, wherein the common liquid chamber is configured by a hollow portion formed in the substrate material on which the wiring member is formed. A pressure chamber communicating with a discharge port for discharging liquid;
A pressure generating means provided on a surface of the pressure chamber opposite to the discharge port, for deforming the pressure chamber;
Regarding the pressure generating means, a common liquid chamber that is disposed on the opposite side of the pressure chamber and supplies the liquid to the pressure chamber;
A wiring member penetrating through the common liquid chamber and erected substantially perpendicular to the surface on which the pressure generating means is formed,
The liquid discharge head according to claim 1, wherein an arrangement density of the wiring members is set so that the electrode connecting portion of the pressure generating means and at least one of the wiring members can be connected.   An image forming apparatus comprising the liquid discharge head according to claim 1.   When electrically connecting a wiring member for supplying a driving signal to a pressure generating means for deforming a pressure chamber having a discharge port for discharging a liquid and an electrode connecting portion of the pressure generating means, an arrangement pitch of the wiring members is set. A method of manufacturing a liquid discharge head, wherein the pitch is smaller than the arrangement pitch of the electrode connection portions. When electrically connecting a wiring member for supplying a driving signal to a pressure generating means for deforming a pressure chamber having a discharge port for discharging a liquid and an electrode connecting portion of the pressure generating means, at least one of the wiring members is A method of manufacturing a liquid discharge head, wherein the arrangement density of the wiring members is set so as to be connected to the electrode connection portion.

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