JP3931972B2 - Inkjet printer head - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to an ink jet printer head, and more particularly to a configuration of a large ink jet printer head in which the number of nozzles arranged in a line is increased.
[0002]
[Prior art]
  In the prior art on-demand type ink jet printer head, as disclosed in Japanese Patent Application Laid-Open No. 2002-36545 and Japanese Patent Application Laid-Open No. 2002-59547, a plurality of plates are stacked to have an ink flow path. A cavity unit is configured, and these plates include a nozzle plate having a plurality of nozzles, a base plate having a pressure chamber for each nozzle, and a manifold connected to an ink supply source and connected to each pressure chamber. It is comprised from the manifold plate etc. which have a chamber. The piezoelectric actuator is configured by alternately stacking common electrodes and individual electrodes as internal electrodes with a piezoelectric ceramic plate interposed therebetween, and an active portion that is an overlapping portion of the individual electrodes and the common electrode becomes the pressure chamber. Further, the piezoelectric actuator and the cavity unit are joined.
[0003]
  By the way, in a normal ink jet printer apparatus, the carriage provided with the ink jet printer head is reciprocated in the width direction (main scanning direction) orthogonal to the paper transport direction (sub scanning direction), and the width direction of the paper. When the printing operation is performed, the nozzle row direction of the inkjet printer head is arranged in parallel with the paper transport direction (sub-scanning direction). Therefore, the printing range (printing length) in the sub-scanning direction, which can be printed by the carriage movement in the main scanning direction, substantially corresponds to the length of each nozzle row. For example, an inkjet printer head in which 72 nozzles are staggered in a length of 1 inch (25.4 mm) in the sub-scanning direction prints in the sub-scanning direction by one movement in the main scanning direction. The possible range (length) is 1 inch.
[0004]
  And with recent increase in printing speed and quality of printers, the number of nozzles in the sub-scanning direction is increased at the same short nozzle interval (dot interval), and the length of the nozzle row is about 2 inches. For example, it is desired to lengthen the nozzle row. In that case, when forming nozzles and pressure chambers on the plate in the cavity unit, due to the manufacturing method such as laser processing or etching processing, and the material of the plate (made of metal or synthetic resin), the interval between the nozzles and pressure chambers is: Regardless of the number, it can be obtained almost exactly as designed.
[0005]
  On the other hand, in order to form as many active portions as the number of the nozzles on the piezoelectric ceramic plate of one piezoelectric actuator, the length of the actuator ceramic plate must be increased.
[0006]
  As is well known, when the piezoelectric actuator is manufactured, the piezoelectric ceramic plate with the common electrode patterned and the piezoelectric ceramic plate with the individual electrode patterned are alternately stacked and then fired. From the firing, the piezoelectric ceramic plate usually contracts in the length direction, the width direction, and the thickness direction, and the contraction amount in the length direction (nozzle row direction) is particularly large. In consideration of the amount of contraction (contraction rate), the interval between the individual electrodes to be patterned is set.
[0007]
[Problems to be solved by the invention]
  However, due to variations in manufacturing accuracy of piezoelectric ceramic plates and variations in firing temperature, the longer the length of the piezoelectric ceramic plates, the more difficult it is to adjust the spacing between the individual electrodes in the finished state to the pressure chamber spacing. As a result, there was a problem that the product yield deteriorated.
[0008]
  In the present invention, instead of increasing the length of the piezoelectric actuator in the nozzle row direction, the piezoelectric actuator is divided into a plurality of columns in the nozzle row direction and arranged in a vertical row. By devising the form of the ink flow path up to this point, it is a technical problem to simply provide a large inkjet printer head while suppressing manufacturing costs.
[0009]
[Means for Solving the Problems]
  In order to achieve the above object, an ink jet printer head according to a first aspect of the present invention includes a plurality of nozzles arranged in a line on the front surface, a pressure chamber corresponding to each nozzle, and a pressure chamber from each pressure chamber. A plurality of plates each having an ink flow path communicating with each nozzle, and manifold chambers for replenishing ink to a plurality of pressure chambers corresponding to the plurality of nozzles in the row after storing ink from an ink supply source; In an inkjet printer head formed by laminating a cavity unit formed by laminating and an actuator for ejecting ink having an active part that can be selectively driven for each pressure chamber,The pressure chamber is divided into a plurality of groups every appropriate number in the row direction of the nozzles,The actuator;Corresponding to each group of pressure chambersDividing into a plurality and arranging a plurality of adjacent end portions of the actuators facing each other, out of the arrangement intervals of the pressure chambers in the cavity unit, theMore than the interval between the pressure chambers in the row direction of the other nozzles between adjacent groupsAn ink flow path that is set large and communicates from each pressure chamber in the cavity unit to the corresponding nozzle is formed to be inclined with respect to the plate thickness direction of the plurality of plates in the cavity unit.
[0010]
  According to a second aspect of the present invention, in the ink jet printer head according to the first aspect of the present invention, the interval between the active portions in each actuator and the corresponding interval between the pressure chambers are set as the nozzle arrangement interval.Same asIt is characterized by being set to.
[0011]
  According to a third aspect of the present invention, in the ink jet printer head according to the first or second aspect, the plurality of nozzles are arranged in four rows, and the nozzles are arranged corresponding to the rows of the nozzles. The actuator is characterized in that four rows of active portions are formed so as to correspond to the rows of the nozzles.
  According to a fourth aspect of the present invention, in the inkjet printer head according to any one of the first to third aspects, an end portion of each actuator facing the end portion of the other adjacent actuator, and a row direction of the nozzles The space between the active portion at the most row end is set to be larger than ½ of the arrangement pitch of the active portions.
  According to a fifth aspect of the present invention, in the ink jet printer head according to the first to fourth aspects, each actuator is overlapped in plan view with an individual electrode corresponding to each pressure chamber and a row of the individual electrodes. The piezoelectric actuator is formed by sandwiching a piezoelectric sheet between the common electrode and the common electrode, and a portion of the piezoelectric sheet between the individual electrode and the common electrode is used as the active portion.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a partially cutaway perspective view of a cavity unit 11 and a piezoelectric actuator 12 in a piezoelectric ink jet printer head 10 according to an embodiment of the present invention. In FIG. On the upper surface of the plate-type piezoelectric actuator 12 to be bonded, a flexible flat cable 13 (see FIGS. 5 and 6) is overlap-bonded with an adhesive for connection to an external device.
[0013]
  The cavity unit 11 is configured as shown in FIGS. That is, a total of nine plates including a nozzle plate 14, a descending plate 15, a damper plate 16, two manifold plates 17, 18, three spacer plates 19, 20, 21 and a base plate 22 on which pressure chambers 23 are formed. Each of the plates 15 to 22 is made of 42% nickel alloy steel plate and has a structure of 50 μm to 150 μm except for the nozzle plate 14 made of synthetic resin. Have a thickness of about.
[0014]
  The nozzle plate 14 has a nozzle 24 for ejecting ink having a very small diameter (in the embodiment, about 25 μm) (reference numerals 24a, 24b, 24c, and 24d are assigned to nozzles in individual rows). 14 in a staggered arrangement of four rows along the first direction (the long side direction of the cavity unit 11 and the X-axis direction in FIG. 2) (see FIG. 2).
[0015]
  That is, the first row of nozzles 24a and the second row of nozzles 24b each have a minute pitch P along two parallel adjacent reference lines (not shown) extending in the first direction of the nozzle plate 14. A plurality of nozzles 24c and a fourth row 24d are formed in a staggered arrangement at intervals of the same distance, and two parallel adjacent reference lines extending in the first direction are also provided. A large number of holes are formed in a staggered arrangement at intervals of a minute pitch P. Further, the set of the first row nozzle 24a and the second row nozzle 24b and the set of the third row nozzle 24c and the fourth row nozzle 24d are arranged in the short side direction (second direction) of the cavity unit 11. 2 are arranged in parallel with a gap in the Y-axis direction (see FIG. 2). In the embodiment, the length of each nozzle row of the first row to the fourth row is 2 inches, and the number of each nozzle 24 is 150, that is, the arrangement density is 75 (dpi [dot per inch]). Yes (see FIG. 5).
[0016]
  Next, two piezoelectric actuators 12 (individually arranged) are arranged so that the pressure chambers 23 are arranged in the column direction (first direction) of the nozzles 24 on the base plate 22 which is the uppermost layer of the cavity unit 11. Will be described from the relationship with the arrangement of the active portion in the reference numerals 12a and 12b).
[0017]
  One piezoelectric actuator 12a (or 12b) has 75 active portions so as to actuate half (75 per row) of pressure chambers 23 in the row direction out of the number of nozzles 24 in the four rows. Arranged. Accordingly, as shown in FIGS. 2 and 6A, one piezoelectric actuator 12a is disposed in the front half of the longitudinal direction (the first direction) of the upper surface of the cavity unit 11, and the other piezoelectric actuator is disposed in the rear half. An actuator 12b is arranged.
[0018]
  In each piezoelectric actuator 12a (or 12b), as will be described in detail later, the common electrode 37 and the individual electrode 36 arranged corresponding to each position of each pressure chamber 23 are alternately sandwiched between the piezoelectric sheets. By applying a voltage between any individual electrode 36 and the common electrode 37, the active portion of the piezoelectric sheet corresponding to the applied individual electrode 36 is distorted by the piezoelectric longitudinal effect in the stacking direction. Will occur. The active portions are formed in the same number in the same row with the same number as the number of pressure chambers 23.
[0019]
  That is, the active portions are arranged along the row direction (first direction) of the nozzles 24 (pressure chambers 23) and in the second direction by the same number as the number of the nozzle rows (four). Are lined up. In addition, each active portion is formed long in the longitudinal direction of the pressure chamber 23 in the second direction (width direction of the cavity unit 11), and an arrangement interval (pitch P) between adjacent active portions is also described later. The arrangement is similar to that of FIG. 4 and is staggered (see FIG. 4).
[0020]
  The pressure chambers 23 are arranged in two groups in the longitudinal direction of the base plate 22 corresponding to the two piezoelectric actuators 12a and 12b. In other words, the pressure chambers 23 of the group corresponding to one actuator 12a correspond to those in the first half of the row direction (first direction) of the nozzles 24, and the pressure chambers 23 of the group corresponding to the other actuator 12b are Corresponding to the latter half of the nozzle 24 in the row direction (first direction), two sets of two staggered arrays each having the same interval as the arrangement interval (pitch P) of the nozzles 24, for a total of four rows Are arranged.
[0021]
  Each of the pressure chambers 23 is formed so as to be long in the width direction (second direction) of the base plate 22 and penetrate the base plate 22 in the thickness direction. One end of each pressure chamber 23 is connected to each of the communication paths formed through the spacer plates 19, 20, 21, the manifold plates 17, 18, the damper plate 16 and the intermediate plate 15 located between the base plate 22 and the nozzle plate 14. The nozzles 24 communicate with each nozzle 24 through 25 (individually labeled 25a, 25b, 25c, 25d, 25e, 25f, and 25g). Further, the other end of each pressure chamber 23 communicates with a manifold chamber 26 described later formed in the spacer plates 19, 20, 21.
[0022]
  As shown in FIGS. 2 and 5, the space L2 between the two groups of pressure chambers 23 is set to be wider in the longitudinal direction of the base plate 22 than the space between the pressure chambers 23 (pitch P). This is because, in manufacturing each piezoelectric actuator 12a, 12b, the distance L1 between the electrodes 36, 37 at the end of the row and the end of the piezoelectric actuator adjacent thereto is made 1/2 or less of the pitch P of the electrodes 36. Therefore, the distance L1 is set to a size that facilitates the manufacture of the piezoelectric actuators 12a and 12b, and a larger interval L2 is set. Adjacent piezoelectric actuators 12a and 12b are positioned with a gap between their ends.
[0023]
  Thereby, since the pitch P of the nozzles 24 is set to be constant in the row direction, the communication path 25 connecting one end of each pressure chamber 23 to the nozzle 24 is inclined with respect to the stacking direction of the plates. become. The communication passage 25 is inclined symmetrically with the center of the interval L2 between the two groups of pressure chambers 23 as a boundary.
[0024]
  Manifold chambers 26 (individually, 26 a, 26 b, 26 c, 26 d, 26 e, 26 f, 26 g, and 26 h) are bored in the two manifold plates 17 and 18 so as to extend along the row of the nozzles 24. It is installed. More specifically, the length of each manifold chamber 26 is a length obtained by dividing the pressure chambers 23 arranged in the direction of each nozzle row into appropriate numbers. In the embodiment, as shown in FIG. Since there are four rows of pressure chambers 23 in the cavity unit 11, the length of one group (the number of pressure chambers 23 in one row is 75) is 1 in the cavity unit 11. Place every two columns. Accordingly, in the embodiment of FIGS. 2 and 3, eight manifold chambers 26a, 26b, 26c, 26d, 26e, 26f, 26g, and 26h are formed. One end portion in the longitudinal direction of each manifold chamber 26 extends to the opposite side of each group so as to communicate with an ink supply hole 31 from an ink supply source (not shown), and in addition to each manifold chamber 26a, 26c, 26e, and 26g. The end is close to the other end of the manifold chambers 26b, 26d, 26f, and 26h of other groups. Further, the depth of each manifold chamber 26 is drilled and formed by laser processing, plasma jet processing, electrolytic etching processing or the like so as to cover the entire plate thickness of the manifold plates 17, 18. The first spacer plate 19 on the upper layer 18 and the damper plate 16 on the lower layer are stacked so as to be sealed. The damper plate 16 is formed with a damper chamber 27 having the same shape as the manifold chamber 26 in plan view and having a plate thickness reduced by etching on the lower surface side.
[0025]
  Of the pressure waves acting on the pressure chamber 23 by driving the piezoelectric actuator 12, the retreat component toward the manifold chamber 26 is absorbed by the vibration of the damper plate 16 having a thin plate thickness to prevent so-called crosstalk. To do.
[0026]
  The second spacer plate 20 is formed with an ink flow restricting portion 28 corresponding to each pressure chamber 23. As shown in FIG. 6B, the diaphragm portion 28 is formed such that the area of both end portions 28a and 28b in the longitudinal direction is large and the middle area is small as shown in FIG. In addition, the longitudinal direction of each throttle portion 28 is formed to be parallel to the longitudinal direction of the pressure chamber 23. Then, the diaphragm portion 28 is sealed by laminating the first spacer plate 19 on the lower surface side of the second spacer plate 20 and the third spacer plate 21 on the upper surface side. A first ink passage 29 formed in the first spacer plate 19 communicates with the manifold chamber 26 and one end portion 28 a of the throttle portion 28. On the other hand, the second ink passage 30 formed in the third spacer plate 21 communicates with the other end portion 28b of the throttle portion 28 and the other end portion of the pressure chamber 23 (see FIG. 6A). .
[0027]
  As shown in FIG. 2, eight large-diameter ink supply holes 31 a, 31 b, 31 c, and so on are provided at both longitudinal ends of the base plate 22, the third, second, and first spacer plates 21, 20, and 19. A hole 31d is formed so as to communicate with the top and bottom and communicate with the end of each manifold chamber 26. In addition, a filter 32 for removing dust in the ink supplied from an ink supply source such as an ink tank above is stretched on the upper surface of the ink supply hole 31a formed in one end of the spacer plate 13. It is installed.
[0028]
  On the other hand, as shown in FIG. 4, each of the piezoelectric actuators 12 includes a plurality of (4 to 10) piezoelectric sheets 33 and 34 each made of a piezoelectric ceramic plate having a thickness of about 30 μm and the top of the uppermost layer. In this structure, the sheet 35 is laminated. Then, on the upper surface (wide surface) of the lowermost piezoelectric sheet 33 and the odd-numbered piezoelectric sheet 33 counting upward from the lowermost piezoelectric sheet 33, as shown in FIG. 4, each location corresponding to each pressure chamber 23 in the cavity unit 11. The narrow individual electrodes 36a, 36b, 36c, and 36d are arranged along the first direction (the long side direction of the piezoelectric sheet 33, the X direction in FIG. 4, the row direction of the nozzles 24a, 24b, 24c, and 24d). It is formed in a shape.
[0029]
  Each individual electrode 36a, 36b, 36c, 36d extends in parallel with the short side of each piezoelectric sheet 33 along a second direction (Y-axis direction) orthogonal to the first direction. In that case, each individual electrode 36a, 36b, 36c, 36d is formed to have a width that is substantially the same as that of each of the pressure chambers 23a, 23b, 23c, 23d and slightly narrower than the pressure chamber in plan view. The first row of individual electrodes 36a and the fourth row of individual electrodes 36d arranged on the outermost row side are respectively arranged on the side close to the side edge of the pair of long sides of each piezoelectric sheet 33. .
[0030]
  In addition, the individual electrode 36b in the second row and the individual electrode 36c in the third row are located near the center in the short side direction of each piezoelectric sheet 33 (near the center between the pair of long sides of each piezoelectric sheet 33). Is located in the region). On the piezoelectric sheet 33 other than the lowermost layer, a dummy common electrode 43 is formed at a location overlapping with a lead portion 37a of the common electrode 37 described later in plan view.
[0031]
  On the other hand, the common electrode 37 is printed on the surface of the even-numbered piezoelectric sheet 34 from the bottom, and the first direction of the piezoelectric sheet 34 (the X-axis direction, the direction along the long side of the piezoelectric sheet 34).InIt consists of two long trunk portions 37a and 37b, and a lead portion 37c connected to both the trunk portions 37a and 37b and extending along the short edge of the piezoelectric sheet 34. The one trunk portion 37a is disposed at a position overlapping with most of the individual electrode 36a in the first row and the individual electrode 36b in the second row in plan view, and along the both sides of the trunk portion 37a. The dummy electrodes 38a and 38b arranged at regular intervals are arranged at positions overlapping with a part of the individual electrodes 36a in the first row and the individual electrodes 36b in the second row in plan view.
[0032]
  Similarly, the other trunk portion 37b is arranged at a position overlapping with most of the individual electrode 36c in the third row and the individual electrode 36d in the fourth row in plan view, while the trunk portion 37b The dummy electrodes 38c and 38d arranged at regular intervals along both sides are arranged at positions overlapping with a part of the third row of individual electrodes 36c and the fourth row of individual electrodes 36d in plan view. Yes.
[0033]
  On the surface (upper surface) of the top sheet 35, four rows of surface electrodes 39a, 39b, 39c, 39d for the four rows of individual electrodes 36a, 36b, 36c, 36d, and a surface electrode 40 for the common electrode 37 are provided. And are provided. Then, except for the lowermost piezoelectric sheet 33, the upper piezoelectric sheets 33 and 34 and the top sheet 35 are respectively provided with the surface electrodes 39a, 39b, 39c and 39d, and the upper and lower positions corresponding to them respectively. Conductive members (conductive paste) in which through-holes 41 are formed in which the electrodes 36a, 36b, 36c, 36d and the dummy electrodes 38a, 38b, 38c, 38d communicate with each other in the vertical direction, and the through-holes 41 are filled. So that they can be electrically connected to each other. Similarly, through-holes 42 communicating with the surface electrode 40 in the top sheet 35, the lead-out portion 37 c of the common electrode 37 in the lower piezoelectric sheet 34 corresponding thereto, and the dummy common electrode 43 in the piezoelectric sheet 33 are vertically connected. The through holes 42 are connected to each other through conductive members (conductive paste) filled in the through holes 42 so as to be electrically connected to each other.
[0034]
  In addition, as a manufacturing method of the piezoelectric actuator 12, the individual electrode, the common electrode, the dummy electrode, the dummy common electrode, and the surface electrode are electrically conductive paste such as silver-palladium paste on the surface of the ceramic substrate which is a piezoelectric sheet. Is formed by screen printing, dried, laminated, and fired. As a matter of course, the dummy electrodes 38a, 38b, 38c, and 38d are formed in an island shape so as not to be electrically connected to the adjacent electrodes and the common electrode 37. Similarly, the dummy common electrode 43 is electrically connected to the individual electrode.SetIt is formed in an island shape so that there is no.
[0035]
  An adhesive sheet (not shown) made of a non-ink-permeable synthetic resin material as an adhesive layer is formed on the entire lower surface (the wide surface facing the pressure chamber 23) of the plate-type piezoelectric actuator 12 having such a configuration. Then, the piezoelectric actuator 12 is bonded and fixed to the cavity unit 11 with the individual electrodes corresponding to the pressure chambers 23 in the cavity unit 11 (see FIG. 5 and FIG. 6 (a)). Further, when the flexible flat cable 13 is pressed against the upper surface of the piezoelectric actuator 12, various wiring patterns (not shown) in the flexible flat cable 13 are changed to the surface electrodes 39. , 40 are electrically joined.
[0036]
  In this configuration, a high voltage for polarization is applied between all the individual electrodes 36 and the common electrode 37 via the surface electrodes 39 and 40 in the piezoelectric actuator 12, so that each individual electrode 36 and the common electrode 37 can be connected to each other. The portions of the piezoelectric sheets 33 and 34 sandwiched between the two are polarized. As a result, the portions of the piezoelectric sheets 33 and 34 sandwiched between the individual electrodes 36 and the common electrode 37 serve as active portions. When a driving voltage is applied between the individual electrode 36 and the common electrode 37 through the arbitrary surface electrode 39 and the surface electrode 40 to generate an electric field parallel to the polarization direction in the corresponding active portion, The active portion extends in the stacking direction, the internal volume of the corresponding pressure chambers 23a to 23d is reduced, and the ink in the pressure chambers 23a to 23d is ejected in the form of droplets from the nozzles 24a to 24d to perform predetermined printing. Is performed (see FIG. 6A).
[0037]
  When four colors of ink (black, cyan, yellow, magenta) are used for color printing, for example, the first row of nozzles 24a is used for discharging black ink, and the second row of nozzles 24b is used for cyan ink. When the third row of nozzles 24c are set to discharge yellow ink and the fourth row of nozzles 24d are set to discharge magenta ink, the first row of manifolds formed on the corresponding manifold plate 17 (18) shown in FIG. The chambers 26a and 26b are filled with black ink, the second row manifold chambers 26c and 26d are filled with cyan ink, the third row manifold chambers 26e and 26f are filled with yellow ink, and the fourth row. The manifold chambers 26g and 26h in the row are filled with magenta ink.
[0038]
  As described above, in the present embodiment, the pressure chambers 23 are divided into two groups along the row direction of the nozzles 24, and the interval between the groups is increased to L2. Regardless of the grouping, it is narrowed to P (<L2), and the communication passage 25 communicating from the pressure chamber 23 to the nozzle 24 is formed in an inclined shape. When a head having a large number of nozzles is manufactured while keeping the same, the piezoelectric actuators 12a and 12b can be used by arranging the nozzles 24 having a short length in the row direction. Accordingly, since the amount of contraction when firing each actuator when the piezoelectric actuator is manufactured is reduced, the variation in the interval between the active portions can be reduced, and a piezoelectric actuator with high dimensional accuracy can be manufactured efficiently.
[0039]
  Further, in the case of an inkjet printer head that has already been developed and has 75 nozzles 24 (pressure chambers 23) in the longitudinal direction (row direction) arranged in a length of 1 inch, piezoelectrics for that purpose are available. By using a plurality of actuators 12, a nozzle array having a length of 2 inches or several inches can be easily manufactured.
[0040]
  Further, assuming that the length, depth, and plan view shape of the manifold chamber in the cavity unit corresponding to the conventional piezoelectric actuator have already been designed, in the embodiment, the length of the nozzle row is 2 inches or several inches. Even in this case, as shown in FIG. 3, the lengths of the manifold chambers 26 in each row are divided to form the same length, depth and plan view shape as those already designed. In other words, the manifold chamber 26 is divided into the longitudinal direction of the cavity unit 11, that is, the half of the total number 150 (2 inches in length) of the pressure chambers 23 (nozzles 24) in the row direction (75 in number (1 inch)). Formed and arranged as described above.
[0041]
  That is, since the manifold chamber 26 is not lengthened in response to the increase in the number of nozzles (the nozzle row is lengthened), the flow path resistance increases and the ink supply amount decreases as the manifold chamber 26 lengthens. There is nothing to do. Further, in order to reduce the flow resistance, it is necessary to increase the width and depth of the manifold chamber 26. In this case, the cavity unit 11 is not only enlarged, but also from the pressure chamber 23 to the manifold chamber by driving the actuator. In order that the component of the pressure wave propagated to the 26th side does not cause crosstalk, the drive voltage, drive timing, drive waveform, and the like of the actuator 12 must be changed. In the above-described embodiment, the actuator chamber drive voltage, drive timing, drive waveform, and the like have already been developed and designed by simply arranging the manifold chamber 26 that has already been developed and designed corresponding to the group of pressure chambers 23. The present invention can be applied almost as it is, and the ejection form of ink from the nozzles 24 can be made the same as before.
[0042]
  In the illustrated embodiment, when the plurality of piezoelectric actuators 12a and 12b are arranged in a row along the row direction of the nozzles 24, a gap is provided between the opposing ends of the actuators 12a and 12b. You may arrange | position so that it may become almost zero.
[0043]
  Thus, if the conventional piezoelectric actuator 12 is used and the manifold chamber 26 is manufactured using the conventional product in the length, depth, and shape in plan view, printing performance and printing accuracy (nozzle dot The density) is almost the same as that of the conventional product, and it is possible to easily realize an inkjet printer head having a long one row, and it is possible to save (shorten) labor (period) and cost required for product design and development. There is an effect.
[0044]
  In the present invention, the number of pressure chambers 23 (nozzles 24) corresponding to the length of the manifold chamber is not limited, and the number of piezoelectric actuators 12 to be arranged is not limited.
[0045]
  It should be noted that the rows of the plurality of nozzles 24 in the cavity unit 11 are four rows, and the manifold chambers 26 arranged corresponding to the rows of the nozzles 24 extend along the direction in which the rows of the nozzles 24 extend. If formed in a substantially parallel shape, there is no inconvenience even if the row of nozzles 24 and the row of manifold chambers 26 are overlapped in a plan view, and a compact one in which the area of the plan view shape of the cavity unit 11 is reduced. There is an effect that it can be produced.
[0046]
  As a modification of the present invention, if two cavity units 11 (piezoelectric actuators 12a and 12b are arranged in tandem in the X-axis direction) shown in FIG. Since an inkjet printer head in which rows having 300 nozzles in an inch are arranged in parallel in four rows is used, when a four-color printer is used in which the ink color is changed for each row, the number of high-density dots ( 150 dpi) and a large printer head having a printing range in the sub-transport direction of 2 inches, and high-speed printing can be achieved at high density.
[0047]
  Moreover, in the said embodiment, although the row | line | column of the nozzle was 4 rows, it can apply with respect to 1 or more nozzle rows in this invention. In addition to actuators that use piezoelectric elements, actuators that vibrate the diaphragm that covers the back of each pressure chamber by static electricity and eject ink from the nozzles, and Joule heat generating elements for each pressure chamber The Joule heat generating element is heated by the drive signal to vaporize the ink in the pressure chamber and pressurize the ink ejected from the nozzle.
[0048]
[Operation and effect of the invention]
  As described above, the ink jet printer head according to the first aspect of the present invention includes a plurality of nozzles arranged in a line on the front surface, a pressure chamber corresponding to each nozzle, and the pressure chamber from the pressure chamber. A plurality of plates each having an ink flow path communicating with each nozzle, and manifold chambers for replenishing ink to a plurality of pressure chambers corresponding to the plurality of nozzles in the row after storing ink from an ink supply source; In an inkjet printer head formed by laminating a cavity unit formed by laminating and an actuator for ejecting ink having an active part that can be selectively driven for each pressure chamber,The pressure chamber is divided into a plurality of groups every appropriate number in the row direction of the nozzles,The actuator;Corresponding to each group of pressure chambersDividing into a plurality and arranging a plurality of adjacent end portions of the actuators facing each other, out of the arrangement intervals of the pressure chambers in the cavity unit, theMore than the interval between the pressure chambers in the row direction of the other nozzles between adjacent groupsAn ink flow path that is set large and communicates from each pressure chamber in the cavity unit to the corresponding nozzle is formed to be inclined with respect to the plate thickness direction of the plurality of plates in the cavity unit.
[0049]
  By configuring in this way, even when the number of nozzles is increased and the nozzle row is lengthened with the nozzle arrangement interval (pitch) being the same as the previous one, the actuator has a short length in the nozzle row direction. Can be used. Therefore, since the amount of contraction when the actuator is manufactured is reduced, the variation in the interval between the active portions can be reduced, and an actuator with high dimensional accuracy can be manufactured efficiently and inexpensively.
[0050]
  This also makes it possible to easily manufacture an ink jet printer head having a nozzle row corresponding to several times the length of the actuator.
[0051]
  According to a second aspect of the present invention, in the ink jet printer head according to the first aspect of the present invention, the interval between the active portions in each actuator and the corresponding interval between the pressure chambers are set as the nozzle arrangement interval.Same asThe large-scale inkjet printer head can be efficiently used without changing the basic performance, changing the drive voltage and drive timing. It can be manufactured and can be used for a printer capable of high-speed printing.
[0052]
  According to a third aspect of the present invention, in the ink jet printer head according to the first or second aspect, the plurality of nozzles are arranged in four rows, and the nozzles are arranged corresponding to the rows of the nozzles. Since the actuator is characterized in that four rows of active portions are formed so as to correspond to the rows of the nozzles, in addition to the effect of the invention according to claim 1 or 2, The effect is that a color ink jet printer can be manufactured in a compact manner.
[Brief description of the drawings]
FIG. 1 is a partial perspective view showing a cavity unit and a piezoelectric actuator of a piezoelectric inkjet printer head according to an embodiment of the present invention separately.
FIG. 2 is an exploded perspective view of a cavity unit.
FIG. 3 is a perspective view of a manifold plate.
FIG. 4 is a partially enlarged perspective view showing an arrangement pattern of individual electrodes and common electrodes in a piezoelectric actuator.
5 is an enlarged cross-sectional view of an intermediate portion of an inkjet printer head in a state where a flexible flat cable, a cavity unit, and a piezoelectric actuator are bonded and fixed as viewed in a cross section in the X-axis direction of FIG. 1 or FIG.
6A is an enlarged cross-sectional view of a midway portion of the inkjet printer head as seen in the cross section in the Y-axis direction of FIG. 1 or FIG. 2, and FIG.
[Explanation of symbols]
    10 Inkjet printer head
    11 Cavity unit
    12 Piezoelectric actuator
    13 Flexible flat cable
    14 Nozzle plate
    15 Intermediate plate
    16 Damper plate
    17, 18 Manifold plate
    19, 20, 21 Spacer plate
    22 Base plate
    23 Pressure chamber
    24 nozzles
    25 Communication path as ink flow path
    26 Manifold room
    27 Damper room
    28 Aperture part
    29, 30 Ink passage
    31a to 31d Ink supply hole
    33, 34 Piezoelectric sheet
    36 Individual electrodes
    37 Common electrode

Claims (5)

A plurality of nozzles arranged in a row on the front surface, a pressure chamber corresponding to each nozzle, an ink flow path communicating from each pressure chamber to each nozzle, and an ink supply source after collecting ink A cavity unit formed by laminating a plurality of plates each having a plurality of pressure chambers corresponding to the plurality of nozzles arranged in a row and a manifold chamber for replenishing ink, and can be selectively driven for each pressure chamber In an inkjet printer head formed by laminating an actuator having an active part and ejecting ink,
The pressure chamber is divided into a plurality of groups every appropriate number in the row direction of the nozzles,
The actuator is divided into a plurality corresponding to each group of the pressure chambers, and a plurality of adjacent actuators are arranged opposite to each other,
Among the arrangement intervals of the pressure chambers in the cavity unit , set between the adjacent groups larger than the arrangement intervals of the pressure chambers in the row direction of the other nozzles ,
An ink jet printer head, wherein an ink flow path communicating from each pressure chamber in the cavity unit to a corresponding nozzle is formed to be inclined with respect to a thickness direction of a plurality of plates in the cavity unit. 2. The ink jet printer head according to claim 1, wherein the interval between the active portions in each actuator and the interval between the corresponding pressure chambers are set to be the same as the arrangement interval of the nozzles. It is assumed that the rows of the plurality of nozzles are four rows, and that the actuators arranged corresponding to the rows of the nozzles have four rows of active portions corresponding to the rows of the nozzles. The ink jet printer head according to claim 1, wherein the ink jet printer head is provided . The distance between the end of each of the actuators facing the end of the other adjacent actuator and the active part at the end of the nozzle in the row direction is more than half of the arrangement pitch of the active parts. 4. The ink jet printer head according to claim 1, wherein the ink jet printer head is set large. Each of the actuators is a piezoelectric actuator formed by sandwiching a piezoelectric sheet between an individual electrode corresponding to each pressure chamber and a common electrode positioned in an overlapping manner in a row of the individual electrode in plan view. The inkjet printer head according to claim 1, wherein a portion of the piezoelectric sheet between the first electrode and the common electrode is the active portion.

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