JP2005199592A - Inkjet recording head and inkjet recording apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make a piezoelectric plate or a laminate piezoelectric plate with a plurality of piezoelectric plates stacked and joined usable in a wide range for a deformation amount to a fixed voltage. <P>SOLUTION: When piezoelectric element groups 252 of a level 1 and a level 3 in a direction X are arranged in the direction X, dots 1 of the level 1 and dots 3 of the level 3 are alternately formed in a direction Y. The dots 1 and the dots 3 are repeated by a high frequency (every printing pitch P), and therefore a size difference of the dots is hardly recognized visually. A size average of the adjacent dots ((level 1+level 3)/2) becomes an equal density to that of a level 2. Moreover, a dot size (density) as the whole of a printing line is averaged, that is, is made the equal density to that of the level 2. A printing quality is prevented from decreasing even if the piezoelectric plates of the level 1 and the level 3 are used. A thickness range of usable piezoelectric plates is increased, and the yield is improved accordingly. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an ink jet recording head and an ink jet recording apparatus.

  The ink jet recording apparatus records characters and images on the recording paper by reciprocating the ink jet recording head in the main scanning direction and transporting the recording paper in the sub scanning direction and selectively ejecting ink droplets from a plurality of nozzles. . A method is known in which an ink jet recording head pressurizes ink in a pressure chamber with a piezoelectric element via a vibration plate, and ejects ink droplets from a nozzle communicating with the pressure chamber.

  The ejection characteristics of the ink jet recording head are affected by the deformation amount of the piezoelectric element with respect to a certain voltage. Also, the difference in thickness of the piezoelectric element affects the amount of deformation. That is, since the piezoelectric element is formed by dividing one piezoelectric plate, the ejection characteristics of the ink jet recording head are affected by the thickness of the piezoelectric plate.

  Therefore, in order to make the ejection characteristics of the inkjet recording head uniform, the piezoelectric plate needs to be within a certain thickness range. For this reason, it is necessary to discard the piezoelectric plate whose thickness is out of the range or process the thickness so that the thickness is within the range. Therefore, there is a limit to the improvement in yield.

  Now, in an ink jet recording head configured by combining a plurality of nozzle units, the ink ejection characteristics are measured for each nozzle unit and classified by level, and nozzle blocks are configured by combining nozzle units of the same level. A method for correcting the ink discharge amount by correcting the drive waveform has been proposed. (For example, refer to Patent Document 1).

However, even with the above method, a piezoelectric element whose deformation amount is outside a certain range (a piezoelectric plate whose thickness is outside a certain range) cannot be used.
In addition, it is necessary to measure the ink ejection characteristics for each nozzle unit and configure the nozzle block according to the level, and it is also necessary to correct the drive waveform for each nozzle block. For this reason, it becomes high-cost.
JP 2001-038892 A

  The present invention has been made to solve the above problems, and enables a piezoelectric plate or a laminated piezoelectric plate formed by laminating and joining a plurality of piezoelectric plates to be used in a wide range with respect to a deformation amount with respect to a constant voltage. For the purpose.

  The inkjet recording head according to claim 1 is a piezoelectric element group configured by dividing one piezoelectric plate or a laminated piezoelectric plate obtained by laminating and joining a plurality of piezoelectric plates into a plurality of piezoelectric elements. An ink jet recording head that individually pressurizes and depressurizes a plurality of pressure chambers filled with ink and ejects ink droplets from a nozzle communicating with the pressure chambers to a recording medium, wherein the piezoelectric element group is displaced by a certain voltage. The piezoelectric element is capable of printing with ink droplets ejected by the piezoelectric elements of the piezoelectric element groups of different levels on a line in the transport direction of the recording medium or in a direction orthogonal to the transport direction. It is characterized by arranging groups.

  The ink jet recording head according to claim 1 is ejected by a piezoelectric element of a piezoelectric element group having a different level of displacement with respect to a constant voltage on a line in a recording medium conveyance direction or a direction orthogonal to the conveyance direction. The piezoelectric element group is arranged so that printing can be performed with ink droplets. Ink droplets ejected by piezoelectric elements of piezoelectric element groups having different displacement amounts have different ink droplet amounts. When the ink droplet amount is different, the size of the dot on the recording medium is also different.

  If only a large displacement amount (large dot) or a small displacement amount (small dot) with respect to a certain voltage is used, the overall print density is too dark or too light. For this reason, the print quality is lowered.

  However, since printing is performed with ink droplets ejected by piezoelectric elements of different levels of piezoelectric element groups on the recording medium conveyance direction or a line orthogonal to the conveyance direction, the recording medium conveyance direction or the conveyance direction is orthogonal. Different sized dots are printed on the direction lines.

  Thus, even when dots having different sizes are printed on the same line, the difference in the size (density) of the dots is hardly recognized visually. Therefore, the print quality can be maintained even when different levels of piezoelectric element groups are used.

  Therefore, the width of the displacement amount with respect to a certain voltage of the usable piezoelectric element group is widened. That is, the range of usable piezoelectric plates or laminated piezoelectric plates is widened. For this reason, the yield is improved, and the ink jet recording head can be manufactured at low cost.

  In addition, when a laminated piezoelectric plate made by laminating and joining multiple piezoelectric plates is divided into each piezoelectric element and each pressure chamber is pressurized or depressurized, even a small thin piezoelectric plate can be driven at a low voltage by laminating. And bends and deforms efficiently.

  The ink jet recording head according to claim 2, wherein the plurality of pressure chambers filled with ink can be individually driven for each pressure chamber, or can be individually driven for each pressure chamber. An inkjet recording head that individually pressurizes and depressurizes a plurality of the piezoelectric plates stacked and joined, and discharges ink droplets from a nozzle communicating with the pressure chamber to a recording medium, the piezoelectric plate, Alternatively, the laminated piezoelectric plates are divided into levels according to the amount of displacement with respect to a constant voltage, and the piezoelectric plates at different levels or the laminated piezoelectric plates on the line in the recording medium conveyance direction or the orthogonal direction to the conveyance direction. The piezoelectric plate or the laminated piezoelectric plate is arranged so as to be able to print with ink droplets ejected by individually driving the piezoelectric plate.

  The ink jet recording head according to claim 2 is capable of printing with ink droplets ejected by individually driving different levels of piezoelectric plates or laminated piezoelectric plates on a recording medium conveyance direction or a line perpendicular to the conveyance direction. A piezoelectric plate or a laminated piezoelectric plate is disposed on the substrate.

  For this reason, printing is performed with ink droplets ejected by individually driving different levels of piezoelectric plates or laminated piezoelectric plates on the conveyance direction of the recording medium or on a line orthogonal to the conveyance direction. Accordingly, dots of different sizes are printed on the line in the recording medium conveyance direction or in the direction orthogonal to the conveyance direction. Therefore, the same effect as in the first aspect is obtained.

  Furthermore, since the piezoelectric plate or the laminated piezoelectric plate can be individually driven for each pressure chamber, it is not necessary to divide into a plurality of piezoelectric elements. For this reason, a manufacturing process is simplified and it can manufacture at lower cost.

  Further, since the piezoelectric element is not divided into a plurality of piezoelectric elements, it is preferable that the piezoelectric plate or the laminated piezoelectric plate is not damaged due to the influence of processing stress or the like.

  The inkjet recording head according to claim 3 is a piezoelectric element group configured by dividing one piezoelectric plate or a laminated piezoelectric plate obtained by laminating and joining a plurality of piezoelectric plates into a plurality of piezoelectric elements. An ink jet recording head that individually pressurizes and depressurizes a plurality of pressure chambers filled with ink and ejects ink droplets from a nozzle communicating with the pressure chambers to a recording medium, wherein the piezoelectric element group is displaced by a certain voltage. The piezoelectric element groups are arranged in two rows and two columns or more when the direction in which the recording medium is transported or the direction perpendicular to the transport direction is the row direction and the direction intersecting the row direction is the column direction. The nozzle group is configured by arranging and arranging the printing pitch along the line in the row direction P, the number of rows of the piezoelectric element group L, and the nozzle communicating with the pressure chamber to which the piezoelectric element of the piezoelectric element group pressurizes and depressurizes. When the nozzle pitch when the nozzle group is projected in a direction orthogonal to the row direction is M, the nozzle groups are arranged shifted in the row direction so that P = M / L. It is characterized by having one or more columns composed of element groups.

  The inkjet recording head according to claim 3, wherein the piezoelectric element groups are arranged in two rows and two columns or more, the printing pitch along the line in the row direction is P, the number of rows of the piezoelectric element groups is L, and the piezoelectric elements are piezoelectric. When a nozzle group is constituted by the nozzles communicating with the pressure chamber to which the element pressurizes and depressurizes, and the nozzle pitch when the nozzle group is projected in a direction orthogonal to the row direction is M, P = M / L. The nozzle groups are arranged so as to be shifted in the row direction.

  When the piezoelectric element group and the nozzle group are arranged in this way, printing is performed at the print pitch P in the row direction in the order of the piezoelectric element groups arranged in the column direction. That is, printing is performed with different piezoelectric element groups at the printing pitch P.

  Accordingly, piezoelectric elements of different levels of piezoelectric element groups, that is, dots having different sizes are printed at the print pitch P, that is, at a high cycle, so that the difference in dot size (density) is not recognized much visually. . Therefore, the print quality can be maintained even when different levels of piezoelectric element groups are used.

  Therefore, the width of the displacement amount of the usable piezoelectric element group is widened. That is, the range of the displacement amount with respect to a certain voltage of the usable piezoelectric plate or the laminated piezoelectric plate is widened. For this reason, the yield is improved, and the ink jet recording head can be manufactured at low cost.

  The ink jet recording head according to claim 4, wherein a plurality of pressure chambers filled with ink can be individually driven for each pressure chamber, or individually driven for each pressure chamber. An inkjet recording head that individually pressurizes and depressurizes a plurality of the piezoelectric plates stacked and joined, and discharges ink droplets from a nozzle communicating with the pressure chamber to a recording medium, the piezoelectric plate, Alternatively, when the laminated piezoelectric plate is divided into levels according to the amount of displacement with respect to a certain voltage, the recording medium conveyance direction or the direction orthogonal to the conveyance direction is the row direction, and the direction intersecting the row direction is the column direction. The piezoelectric plate or the laminated piezoelectric plate is arranged in two rows and two columns or more, and the printing pitch along the line in the row direction is set to P, the piezoelectric plate, or the laminated piezoelectric plate. When the nozzle group is composed of L, the piezoelectric plate, or the nozzle connected to the pressure chamber to which the laminated piezoelectric plate individually increases / decreases pressure, and the nozzle group is projected in a direction orthogonal to the row direction When the nozzle pitch of the nozzle is M, the nozzle groups are arranged so as to be shifted in the row direction so that P = M / L, and a column composed of different levels of the piezoelectric plates or the laminated piezoelectric plates is 1 It is characterized by having more than one row.

  5. The ink jet recording head according to claim 4, wherein a piezoelectric plate or a laminated piezoelectric plate is arranged in two rows and two columns or more, and the print pitch along the line in the row direction is P, the number of rows of the piezoelectric plate or the laminated piezoelectric plate. Is a nozzle group composed of nozzles communicating with pressure chambers that individually pressurize or depressurize the piezoelectric plate or laminated piezoelectric plate, and the nozzle pitch when the nozzle group is projected in a direction perpendicular to the row direction is M , The nozzle groups are arranged so as to be shifted in the row direction so that P = M / L.

  When the piezoelectric plate or the laminated piezoelectric plate and the nozzle group are arranged in this way, printing is performed at the print pitch P in the row direction in the order of the piezoelectric plate or the laminated piezoelectric plate arranged in the column direction. That is, printing is performed with a piezoelectric plate or a laminated piezoelectric plate that differs in printing pitch P.

  Therefore, since different levels of piezoelectric plates or laminated piezoelectric plates, that is, dots of different sizes are printed at the printing pitch P, that is, at a high cycle, the difference in dot size (density) is not much recognized visually. Not. Therefore, the print quality can be maintained even when different levels of piezoelectric plates or laminated piezoelectric plates are used. Therefore, an effect similar to that of the third aspect is achieved.

  Furthermore, since the piezoelectric plate or the laminated piezoelectric plate can be individually driven for each pressure chamber, it is not necessary to divide into a plurality of piezoelectric elements. Therefore, an effect similar to that of the second aspect is achieved.

  The inkjet recording head according to claim 5 is the configuration according to claim 2 or claim 4, wherein the piezoelectric plate or the laminated piezoelectric plate has the pressure chamber depending on a pattern of electrodes formed on the piezoelectric plate. It is characterized in that it can be driven individually.

  In the ink jet recording head according to the fifth aspect, the piezoelectric plate or the laminated piezoelectric plate can be individually driven for each pressure chamber by an electrode pattern formed on the piezoelectric plate. Therefore, the same effect as in claim 2 or claim 4 is obtained.

  An ink jet recording head according to a sixth aspect of the invention is the ink jet recording head according to any one of the third to fifth aspects, wherein the piezoelectric element group, the piezoelectric plate, or the laminated piezoelectric plate of the different levels are arranged. The average value of the deformation amount of the piezoelectric element group, the piezoelectric plate, or the laminated piezoelectric plate, and the center value of the deformation amount divided by level are approximately the same.

  The inkjet recording head according to claim 6, the average value of the deformation amount of the piezoelectric element group, the piezoelectric plate, or the laminated piezoelectric plate in a row composed of different levels of piezoelectric element groups, piezoelectric plates, or laminated piezoelectric plates; It almost coincides with the center value of the deformation amount divided by level.

  Therefore, the average of the size (density) of dots printed by a row composed of piezoelectric element groups, piezoelectric plates, or laminated piezoelectric plates at different levels is equal to the size of the dots (density) printed at the center value of the deformation amount. It almost agrees.

  Accordingly, dots are printed on the same line at different print pitches P, and the dot size (density) is averaged over the entire line. Therefore, the printing quality is further improved.

  An ink jet recording head according to a seventh aspect of the invention is the ink jet recording head according to any one of the third to sixth aspects, wherein the piezoelectric element group, the piezoelectric plate, or the laminated piezoelectric plate at different levels are arranged. The piezoelectric element group, the piezoelectric plate, or the laminated piezoelectric plate has a high deformation amount and a low deformation amount, the piezoelectric plate, or the laminated piezoelectric plate with respect to the central value of the deformation amount divided into levels. However, it is characterized by being arranged alternately.

  In the ink jet recording head according to the seventh aspect, piezoelectric element groups, piezoelectric plates, or laminated piezoelectric plates having a high deformation amount and a low deformation amount are alternately arranged with respect to the central value of the deformation amount divided into levels.

  Therefore, a large dot printed on a high deformation amount piezoelectric element group, a laminated piezoelectric plate, or a piezoelectric plate, and a small dot printed on a low deformation amount piezoelectric element group, a laminated piezoelectric plate, or a piezoelectric plate, Printing is performed alternately at a printing pitch P in the line direction.

  That is, since large dots and small dots are alternately printed at a high cycle of the print pitch P on the same line, it is difficult to visually recognize the difference in dot size (density). Therefore, the printing quality is improved.

  An ink jet recording head according to an eighth aspect of the present invention is the configuration according to any one of the third to seventh aspects, wherein the piezoelectric element group, the piezoelectric plate, or the laminated piezoelectric plate at different levels are arranged. The piezoelectric element group, the piezoelectric plate, or the laminated piezoelectric plate is an average value of deformation amounts of two piezoelectric element groups, the piezoelectric plate, or the laminated piezoelectric plate that are adjacent in the column direction, and the amount of deformation divided into levels. It is characterized in that the center value of the two substantially coincides.

  In the ink jet recording head according to claim 8, the average value of the deformation amounts of the two piezoelectric element groups, piezoelectric plates, or laminated piezoelectric plates adjacent in the column direction substantially coincides with the central value of the deformation amount divided by level. ing.

  For this reason, the average size (density) of adjacent dots is always substantially the same as the average dot size (density). Therefore, the printing quality is improved.

  An ink jet recording head according to a ninth aspect is the configuration according to any one of the third to eighth aspects, wherein a row is arranged at a boundary between the piezoelectric element group, the piezoelectric plate, or the laminated piezoelectric plate in adjacent columns. The nozzles are arranged such that the nozzles of the piezoelectric element groups, the laminated piezoelectric plates, or the laminated piezoelectric plates in different rows overlap on the same line when projected in a direction orthogonal to the direction.

  When the ink jet recording head according to claim 9 is projected in a direction orthogonal to the row direction at the boundary between the piezoelectric element groups, piezoelectric plates, or laminated piezoelectric plates in adjacent columns, the piezoelectric element groups, piezoelectric plates in different rows, Alternatively, the nozzles are arranged so that the nozzles of the laminated piezoelectric plate overlap on the same line. Therefore, it is possible to print on the same line with respect to the column direction using piezoelectric element groups, laminated piezoelectric plates, or piezoelectric plates in different rows.

  For example, when a low-level piezoelectric element group, a laminated piezoelectric plate, or a piezoelectric plate are adjacent, a row of small dots continues. For this reason, the density of the continuous portion decreases and becomes conspicuous. However, the density drop in the continuous portion can be made inconspicuous by printing by including the dots printed by the high-level piezoelectric element group, laminated piezoelectric plate, or piezoelectric plate adjacent to this row in the same row. Therefore, the printing quality is improved.

  An ink jet recording head according to a tenth aspect of the present invention is the configuration according to any one of the third to ninth aspects, wherein the number of rows of the piezoelectric element group, the piezoelectric plate, or the laminated piezoelectric plate is L, and the nozzle group. The relationship between T = ((n × P) + (P / L)), where T is the interval between the lines, P is the print pitch along the line in the row direction, and n is an arbitrary integer. It is said.

  The ink jet recording head according to claim 10, wherein the number of rows of the piezoelectric element group, the piezoelectric plate or the laminated piezoelectric plate is L, the row interval between the nozzle groups is T, and the print pitch along the line in the row direction is P, n Is an arbitrary integer, T = ((n × P) + (P / L)). For this reason, dots are printed at P / L line intervals, and each line is printed with a different piezoelectric element group, piezoelectric plate, or laminated piezoelectric plate.

  Accordingly, different piezoelectric element groups, piezoelectric plates, or laminated piezoelectric plates, that is, dots of different sizes are printed with a print pitch P in the row direction and P / L shifted in the column direction. Therefore, since the gaps (white areas) between the dots are filled, the print quality is further improved.

  An ink jet recording head according to an eleventh aspect is characterized in that, in the configuration according to any one of the first to tenth aspects, the amount of displacement is defined by an electrostatic capacity of the piezoelectric plate.

  In the ink jet recording head according to an eleventh aspect, the displacement is defined by the capacitance of the piezoelectric plate. Therefore, the level can be divided by measuring the capacitance without directly measuring the displacement. Therefore, the level of the piezoelectric plate or the laminated piezoelectric plate can be easily divided.

  An ink jet recording head according to a twelfth aspect is characterized in that, in the configuration according to any one of the first to tenth aspects, the amount of displacement is defined by the thickness of the piezoelectric plate.

  In an ink jet recording head according to a twelfth aspect, the amount of displacement is defined by the thickness of the piezoelectric plate. Therefore, the level can be classified by measuring the thickness of the piezoelectric plate without directly measuring the displacement. Therefore, the level of the piezoelectric plate or the laminated piezoelectric plate can be easily divided.

  An ink jet recording head according to a thirteenth aspect is characterized in that, in the configuration according to any one of the first to twelfth aspects, the piezoelectric plate is formed by firing and the thickness is not adjusted after firing.

  In the ink jet recording head according to the thirteenth aspect, the piezoelectric plate is formed by firing, and the thickness is not adjusted after firing. Since the thickness is not adjusted after firing, the cost is low, but the variation in the thickness direction is large. That is, the variation of the displacement amount with respect to a certain voltage of the piezoelectric plate is large.

  However, since the inkjet recording head according to the first to twelfth aspects has a wide range of usable piezoelectric plates, there are many piezoelectric plates that can be used even when there is a large variation in the amount of displacement of the piezoelectric plates after firing. Therefore, the yield is improved, and the ink jet recording head can be manufactured at low cost.

  An ink jet recording apparatus according to a fourteenth aspect is equipped with the ink jet recording head according to any one of the first to thirteenth aspects.

  Since the ink jet recording apparatus according to claim 14 is mounted with the ink jet recording head according to any one of claims 1 to 13, it is a low cost ink jet recording apparatus.

  As described above, according to the present invention, a piezoelectric plate or a laminated piezoelectric plate formed by laminating and joining a plurality of piezoelectric plates can be used in a wide range with respect to a deformation amount with respect to a constant voltage. .

  Hereinafter, a first embodiment of an inkjet recording head according to the present invention will be described with reference to the drawings.

  As shown in FIG. 1, the ink jet recording head 112 includes a nozzle 10 that ejects ink droplets Q (see FIG. 2B), and a pressure chamber 12 that ejects ink droplets Q from the nozzles 10 that pressurize and communicate with ink. The nozzle communication chamber 16 communicates with the nozzle 10 and the pressure chamber 12, and the ink supply path 18 communicates with the pressure chamber 12.

  As shown in FIG. 2, a vibration plate 34 is bonded to the upper surface of the pressure chamber 12, a piezoelectric element 36 is bonded to the upper surface of the vibration plate 34, and wiring is provided on the upper surface of the piezoelectric element 36 via ball solder 40. The substrate 38 is bonded. Electrodes 202 (see FIG. 8A) are formed on the upper and lower surfaces of the piezoelectric element 36.

  In addition, an ink supply path 18 that supplies ink communicates with the pressure chamber 12. The ink supply path 18 and the common ink flow path 14 communicate with each other through the opening 20, and the common ink flow path 14 is connected to an ink supply port (not shown).

  The diaphragm 34 and the piezoelectric element 36 corresponding to the pressure chamber 12 are referred to as an actuator 35. The nozzle 10, the pressure chamber 12, the nozzle communication chamber 16, the ink supply path 18, and the actuator 35 constitute an ejector 50.

  As shown in FIG. 3, in the inkjet recording head 112, ejector groups 52 in which the ejectors 50 are arranged in a matrix are arranged in four columns in the X direction and two rows in the Y direction. A group of each nozzle 10 in each ejector group 52 is referred to as a nozzle group 152.

  As shown in FIGS. 4 and 5, each ejector group 52 has the actuators 35 arranged symmetrically with respect to the center point O as a target point. Further, the direction of the actuator 35 is different from the boundary K. The ejector 50 has the same orientation according to the orientation of the actuator 35. With such an arrangement, the actuators 35 arranged on the boundary of the ejector group 52 in the Y direction are all directed inward.

  FIG. 6 is a diagram schematically showing the arrangement of the nozzles 10. Note that FIG. 6 is drawn less than the actual number of nozzles 10 for easy understanding.

  The nozzles 10 of each nozzle group 152 (ejector group 52) are arranged in a matrix, and when projected in the X direction, are arranged at intervals M in the Y direction. (Nozzle pitch M). If the number of rows of the nozzle group 152 (ejector group 52) is L (two rows in this embodiment), the columns of the nozzle group 152 (ejector group 52) are shifted from each other by M / L in the row direction (Y direction). ing.

  Therefore, as shown in FIG. 6B, when the nozzles 10 are projected in the X direction, the nozzles 10 are arranged at intervals P (printing pitch P) = M / L.

  Further, as shown in FIGS. 3 and 6, a gap S is opened between the Y-direction ejector groups 52, but the intervals M (nozzle pitch) of the nozzles 10 are equal. This is because, as described above, the actuators 35 arranged on the boundary of the ejector group 52 in the Y direction are all directed inward. (See FIG. 4).

  In such an ink jet recording head 112, as shown by an arrow F in FIG. 1B, ink introduced from an ink supply port (not shown) of the ink jet recording head 112 is filled into the common ink flow path 14, and this common Each pressure chamber 12 is filled with ink from the ink flow path 14 through the ink supply path 18.

  As shown in FIG. 2B, when a drive voltage waveform is applied to the piezoelectric element 36 in a state where each pressure chamber 12 is filled with ink, the diaphragm 34 bends together with the piezoelectric element 36 as indicated by a dotted line. The ink is deformed, the ink in the pressure chamber 12 is pressurized, and the ink droplet Q is ejected from the nozzle 10.

  Next, the outline of the manufacturing method of the ink jet recording head 112 will be described below.

  As shown in FIG. 7A, the nozzle plate 22 in which the nozzles 10 are formed, the ink pool plates 24 and 26 in which the nozzle communication chamber 16 and the holes that form the common ink flow path 14 are formed, and the nozzle communication chamber 16. And a through plate 28 in which a hole to be the opening 20 of the common ink flow path 14 is formed, an ink supply path plate 30 in which a hole to be the ink supply path 18 is formed, and a hole to be the pressure chamber 12. The pressure chamber plates 32 are laminated and joined in order.

  The material of the nozzle plate 22 is polyimide, and the material of the nozzle plate 22, the ink pool plates 24 and 26, the through plate 28, and the pressure chamber plate 32 is SUS.

  Next, as shown in FIG. 7B, the surface of the nozzle plate 22 is covered with a water repellent coating film (not shown), and the nozzle 10 is opened with the excimer laser B.

  On the other hand, as shown in FIG. 8A, a circular piezoelectric plate 200 having a diameter D (maximum length) of about 12 mm and a thickness t of about 40 μm is fired.

  In addition, it is easy to be damaged when the thickness t is 10 μm or less, and is difficult to handle in the subsequent steps. Furthermore, it is easily affected by pinholes, which causes a decrease in yield due to short circuit or dielectric breakdown. Moreover, since it is hard to bend and deform | transform when it is 75 micrometers or more, it is necessary to cut thinly. Therefore, 10 μm to 75 μm is suitable as a thickness that does not adjust the thickness after firing. In the present embodiment, since the thickness t is about 40 μm and is 10 μm to 75 μm, the thickness adjusting step is not necessary in the subsequent steps.

  In addition, the detail about the range of the thickness t after baking which can be used is mentioned later.

  Furthermore, when the relationship between the maximum length D and the thickness t is D> 500 t, the thickness is too thin for the size (maximum length D) and it is difficult to handle. Moreover, it is difficult to fire the piezoelectric plate. Therefore, D ≦ 500t is dripping in the relationship between the thickness t after firing and the maximum length D. In the present embodiment, the relationship between the maximum length D (about 12 mm) and the thickness t (about 40 μm) is D ≦ 500 t.

  At this time, the electrode 202 (material AgPdb, thickness 12 μm) is also formed on both sides at the same time.

  The reason why the electrode 202 can be baked at the same time as the baking of the piezoelectric plate 200 is that the piezoelectric plate 200 can be used without adjusting the thickness after baking. In addition, since the electrode 202 is baked simultaneously with the firing of the piezoelectric plate 200, the manufacturing process is simplified and can be manufactured at low cost.

  The electrode 202 may be baked after the piezoelectric plate 200 is baked. In this case, the electrode 202 can be formed at a temperature lower than the firing temperature of the piezoelectric plate 200. Therefore, the range of selection of materials used for the electrode 202 is widened.

  In FIG. 8A, the electrode 202 is drawn thick for easy understanding. Further, the electrode 202 is omitted except for FIG.

  Next, as shown in FIG. 8B, the piezoelectric plate 200 is cut out to form a square piezoelectric plate 204 having a side H of about 7.0 mm.

  As shown in FIG. 8C, the piezoelectric plate 204 is bonded to the intermediate holding member 208 via a heat-foamable adhesive film 206 that has a property of foaming and greatly reducing the adhesive force when heated at a predetermined temperature. . In the case of this embodiment, a total of eight piezoelectric plates 204 are arranged and bonded together in 4 columns × 2 rows.

  In this embodiment, the piezoelectric plate 204 is thin with a thickness t of about 40 μm. As described above, the relationship between the maximum length D (about 12 mm) and the thickness t (about 40 μm) is D ≦ 500 t. Thus, handling is easy even in such an adhesion process, and the yield does not deteriorate.

  In addition, the thin piezoelectric plates 204 are arranged in 4 columns × 2 rows so as to be long. For this reason, since the piezoelectric plate 204 can be used without adjusting the thickness after firing, it is not necessary to thin the piezoelectric plate by lapping or the like as in the prior art, and it can be manufactured at low cost.

  Details of how the piezoelectric plates 204 are arranged will be described later.

  Furthermore, compared with a method of thinning a thickly baked piezoelectric plate by lapping or the like, there is no extra piezoelectric material to be cut by lapping or the like, and the material cost is low. In addition, since there is no piezoelectric material to scrape and discard, it also addresses environmental issues.

  As shown in FIG. 8D, each piezoelectric plate 204 is divided in correspondence with the pressure chambers 12 (see FIG. 2) by mechanical processing such as sandblasting to form a plurality of piezoelectric elements 36.

  Note that the method of dividing may be other methods. For example, the piezoelectric plate 204 may be divided into a plurality of piezoelectric elements 36 by chemical processing such as etching. In the chemical processing, for example, there is no influence of processing stress applied to the piezoelectric plate 204 with respect to mechanical processing such as sandblast processing, so that there is no occurrence of failure such as breakage.

  A plurality of piezoelectric elements 36 produced from this single piezoelectric plate 204 constitute a piezoelectric element group 252 corresponding to the ejector group 52 described above.

  As shown in FIGS. 4 and 5, the piezoelectric elements 36 are arranged symmetrically with respect to the center O of the piezoelectric element group 252 (ejector group 52). Therefore, as shown in FIG. 2, the interval M between the nozzles 10 is uniform, but the gap S is opened between the piezoelectric elements 36 of the piezoelectric element group 252 (ejector group 52), so that the assembly is easy. There is no problem.

  Then, as shown in FIG. 7D, the surface of the piezoelectric element 36 of the intermediate holding member 208 on which the piezoelectric element 36 is formed is joined to the diaphragm 34.

  As shown in FIG. 7E, after bonding to the diaphragm 34, the intermediate holding member 208 is heated to reduce the adhesive force of the thermally foamable adhesive film 206, and the intermediate holding member 208 is peeled off.

  Finally, as shown in FIG. 7F, a wiring board 38 on which ball solder 40 is formed for each piezoelectric element 36 is joined to the piezoelectric element 36.

  Since the electrodes 202 (see FIG. 8A) are formed on both surfaces of the piezoelectric element 36, the electrode 202, that is, the piezoelectric element 36 and the wiring board 38 are electrically connected. The wiring board 38 and the diaphragm 34 are connected by a conductive adhesive or the like.

8D, the process of dividing each piezoelectric plate 204 corresponding to the pressure chamber 12 to form a plurality of piezoelectric elements 36 is performed by joining the piezoelectric plate 204 to the vibration plate 34 and holding it in the middle. After the member 208 is peeled off, it may be divided into a plurality of piezoelectric elements 36. That is, the process of FIG. 8D may be brought between FIG. 7E and FIG.
As described above, when the piezoelectric plate 204 is joined to the vibration plate 34 and then divided into the plurality of piezoelectric elements 36, it can be divided into the plurality of piezoelectric elements 36 while confirming the position of the pressure chamber 12 directly. For this reason, the positioning accuracy of the pressure chamber 12 and the piezoelectric element 36 is improved. Therefore, variation in the ejection characteristics of the ink droplet Q (see FIG. 2B) can be reduced.

  Further, the adhesive does not stick between the diaphragm 34 and the piezoelectric element 36. Accordingly, it is possible to reduce deterioration and variation in the ejection characteristics of the ink droplets Q due to the sticking out of the adhesive.

  Further, the piezoelectric element group 252 (piezoelectric plate 204) is arranged in two or more columns in the vertical and horizontal directions (4 columns × 2 rows in this embodiment), and the thickness of one piezoelectric plate 204 is reduced without adjusting the thickness after firing. The piezoelectric plate 204 can be used. For this reason, the cost regarding the process to the thickness direction of the piezoelectric plate 204 can be reduced. Further, even a thin piezoelectric plate 204 (about 40 μm in this embodiment) has a small size (in this embodiment, a square having a side H of about 7.0 mm) and is not easily damaged.

  Therefore, the handleability in the manufacturing process is good, the defects in the manufacturing process are reduced, and the cost can be reduced. Furthermore, since the piezoelectric plate 200 and the electrode 202 are fired at the same time and used as they are, the cost for forming the electrode 202 separately after firing is reduced.

  As described above, the inkjet recording head 112 can be made long at low cost.

  As described above, the inkjet recording head 112 of the present embodiment is used without adjusting the thickness (t = about 40 μm) of the piezoelectric plate 200 after firing. Therefore, the piezoelectric plate 200 can be manufactured at a low cost.

  However, the thickness of the fired piezoelectric plate 200 varies greatly. When the thickness is different, the displacement amount of the piezoelectric element 38 when the constant voltage is applied (the deflection amount of the actuator 35 indicated by the dotted line in FIG. 2B) is different.

  When the displacement amount is different, the excluded volume of the pressure chamber 12 is different as shown in the graph of FIG. That is, the droplet amount (ink discharge amount) of the ink droplet Q (see FIG. 2B) changes. Therefore, the size of the dots formed by the ink droplets Q landing on the recording medium differs.

  As shown in the graph of FIG. 15, the thickness range (38 μm ≦ t ≦ 42 μm) of the piezoelectric plate 200 with an appropriate ink droplet amount is set to level 2, and the thickness of the piezoelectric plate 200 with an ink droplet amount smaller than level 2 (37 μm). ≦ t <38 μm) is level 1, and the thickness (42 μm <t ≦ 43 μm) of the piezoelectric plate 200 that has a larger ink droplet amount than level 2 is level 3.

  A dot having a size formed by the ink droplet Q ejected by the piezoelectric element 38 of the level 1 piezoelectric plate 200 (piezoelectric element group 252) landing on the recording medium is defined as dot 1. Similarly, level 2 corresponds to dot 2, and level 3 corresponds to dot 3.

  When only level 2 is used, a good image can be formed as shown in FIG. However, if only level 1 is used, the dots are too small as shown in FIG. 26B, and if only level 3 is used, the dots are too large as shown in FIG. .

  Therefore, the piezoelectric plates 200 other than level 2 must be discarded, resulting in a decrease in yield.

  Therefore, in this embodiment, the arrangement of the piezoelectric element group 252 (piezoelectric plate 204) (see FIGS. 3, 8C, and 4D) is arranged as follows, so that the level 1 and the level 3 are arranged. The piezoelectric plate 200 can also be used.

  The displacement amount of the piezoelectric element 38 with respect to a certain voltage can be predicted by measuring the thickness of the piezoelectric plate 200 as described above. Therefore, in the present embodiment, the amount of displacement of the piezoelectric element 38 with respect to a certain voltage is divided into levels by measuring the thickness t of the piezoelectric plate 200. Therefore, the piezoelectric plate 200 can be easily divided into levels.

  The amount of displacement of the piezoelectric element 38 with respect to a certain voltage can also be predicted by measuring the capacitance of the piezoelectric plate 200. Therefore, even if the capacitance of the piezoelectric plate 200 is measured, the level can be easily divided.

  As described above, when the nozzles 10 are projected in the X direction, the nozzles 10 are arranged at intervals P (printing pitch P) = M / 2. (See FIG. 6).

  6B, on the line in the Y direction, ink droplets ejected by the piezoelectric elements 38 in the upper piezoelectric element group 252 and piezoelectric elements 38 in the lower piezoelectric element group 252 are shown. The ink droplets discharged by the ink alternately form dots.

  Therefore, as shown in FIG. 16A, when the level 1 and level 3 piezoelectric element groups 252 are arranged in the X direction, the level 1 dot 1 and level 3 in the Y direction as shown in FIG. And dots 3 are alternately formed.

  Thus, since the dots 1 and 3 are repeated at a high frequency (for each printing pitch P), the difference in the size of the dots is hardly recognized visually. The average of the sizes of adjacent dots ((dot 1 + dot 3) / 2) has a density (dot 2) equivalent to level 2. Further, the dot size (density) of the entire print line is also averaged, that is, the density (dot 2) equivalent to level 2 is obtained.

  Therefore, even if the level 1 and level 3 piezoelectric plates 200 are used, the print quality does not deteriorate. Therefore, the range of the thickness of the piezoelectric plate 200 that can be used is widened, and the yield is improved.

  The arrangement of the piezoelectric element group 252 (piezoelectric plate 204) may be other than the above arrangement. Other examples will be described below.

  As shown in FIG. 17 (A), it may be configured to include a row of level 2 piezoelectric element groups 252.

  With such a configuration, as shown in FIG. 17B, after dot 1 and dot 3 are alternately formed, dot 2 continues, and again, dot 1 and dot 3 are alternately formed. After that, a pattern in which dots 2 continue is obtained.

  Alternatively, the level may be divided into five levels from Lv1 to Lv5 in more detail, for example, as shown in the graph of FIG. Similarly, level 4 corresponds to dot 4 and level 5 corresponds to dot 5.

  As shown in FIG. 19 (A), when level 1 and level 5 are alternately arranged in the X direction, as shown in FIG. 19 (B), dot 1 and dot 5 have a high frequency (for each print pitch P). Repeated.

  Alternatively, as shown in FIG. 20A, a combination of level 1 and level 5, level 2 and level 4, and level 3 may be used.

  In such a configuration, as shown in FIG. 20B, after dot 1 and dot 5 are alternately formed, dot 2 and dot 4 are alternately formed, and dot 3 is formed. It becomes.

  In such a pattern as well, large (high density) dots 5 and 4 and small (low density) dots 1 and 2 are repeated at a high frequency (printing pitch P). Is hardly recognized.

  Next, a second embodiment of the ink jet recording head according to the present invention will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected to the member demonstrated in 1st Embodiment, and the overlapping description is abbreviate | omitted.

  In the first embodiment, the piezoelectric element group 252 (piezoelectric plate 204) has a configuration of four columns in the X direction and two rows in the Y direction, but the ink jet recording head 212 of the second embodiment is shown in FIG. Thus, the piezoelectric element group 252 (piezoelectric plate 204) has a configuration of 3 rows × 3 columns.

  The nozzles 10 of each nozzle group 152 are arranged in a matrix, and are arranged at M intervals in the Y direction. (Nozzle pitch M). Note that FIG. 21 is drawn less than the actual number of nozzles 10 for the sake of clarity.

  Further, the nozzle group 152 in the Y direction is displaced by M / L in the Y direction when the number of rows is L (3 in the present embodiment). Therefore, when the nozzles are projected in 10 directions in the X direction, the nozzles are arranged at intervals P (printing pitch P) = M / 3.

  An arrangement example of the piezoelectric element group 252 (piezoelectric plate 204) configured in such 3 rows × 3 columns will be described.

  As shown in FIG. 22A, when the levels 1, 2, and 3 are arranged in the X direction, dots 1, 2, and 3 are continuously formed repeatedly in the Y direction as shown in FIG. Thus, since the dots 1, 2 and 3 are repeated at a high frequency (for each printing pitch P), the difference in the size of the dots is hardly recognized visually. Further, the dot size (density) of the entire print line is also averaged ((dot 1 + dot 2 + dot 3) / 3), that is, the density is equivalent to level 2 (dot 2).

  Alternatively, as shown in FIG. 23A, level 1 and level 3 are alternately arranged in the X direction so that dots 1 and 3 are repeatedly formed in the Y direction as shown in FIG. May be. Thus, since the dots 1 and 3 are repeated at a high frequency (for each printing pitch P), the difference in the size of the dots is hardly recognized visually. Further, the average of the sizes of adjacent dots ((level 1 + level 3) / 2) has a density equivalent to level 2.

  Next, a third embodiment of the ink jet recording head according to the present invention will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected to the member demonstrated in 1st Embodiment and 2nd Embodiment, and the overlapping description is abbreviate | omitted.

  The arrangement of the piezoelectric element group 252 (piezoelectric plate 204) of the inkjet recording head 312 of the third embodiment is the same as that shown in FIG.

  However, in the switching portion J from the repetition of levels 1 and 3 shown in FIG. 17A to the level 2 (at the boundary of the piezoelectric element group 252), projection is performed in the X direction as shown in FIG. Then, the nozzles 10 are arranged so that the nozzles 10 of the piezoelectric element groups 252 (level 1 and level 2) in different Y directions overlap on the same line (R portion). Note that FIG. 24A is drawn with less than the actual number of nozzles 10 for easy understanding.

  That is, in the R portion, dots (dot 1 and dot 2) can be formed by the piezoelectric element group 252 of both the level 1 piezoelectric element group 252 and the level 2 piezoelectric element group 252.

  In FIG. 17B, dot 1 and dot 2 are arranged in the Y direction at the switching portion J from level 1 and level 3 repetition to level 2 switching. For this reason, the switching portion J has a low concentration.

  In the present embodiment, as described above, level 1 and level 2, that is, dot 1 and dot 2 can be formed on the line in the Y direction of the switching portion. (See FIG. 124A).

  Therefore, as shown in FIG. 24B, by forming the dot 1 and the dot 2 together in the R portion (X direction), the R portion does not have a low density, and the print quality is improved.

  Next, a fourth embodiment of the ink jet recording head according to the present invention will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected to the member demonstrated in 1st Embodiment to 3rd Embodiment, and the overlapping description is abbreviate | omitted.

  The arrangement of the piezoelectric element group 252 (piezoelectric plate 204) of the inkjet recording head 412 of the third embodiment is the same as that shown in FIG.

  As shown in FIG. 25A, the number L of rows in the X direction of the piezoelectric element group 252 (2 in this embodiment), the interval in the X direction between the nozzle groups 152 is T, and the print pitch along the line in the Y direction. Is P and n is an arbitrary integer, the relationship is T = ((n × P) + (P / L)). Note that FIG. 25A is drawn with less than the actual number of nozzles 10 for easy understanding.

  With this arrangement, the dots formed by the ink droplets Q ejected by the piezoelectric elements 38 of the upper piezoelectric element group 252 and the piezoelectric elements 38 of the lower piezoelectric element group 252 eject as shown in FIG. The dots formed by the ink droplets Q are formed with a printing pitch P shifted in the Y direction and a P / 2 pitch shifted in the X direction.

  Therefore, as can be seen from a comparison between FIG. 17B and FIG. 25B, the gap between the dots is reduced, and the print quality is further improved.

  Next, an ink jet recording apparatus 102 equipped with any of the ink jet recording heads 112, 212, 312, and 412 of the first to fourth embodiments will be described. In the following description, an example in which the inkjet recording head 112 of the first embodiment is mounted will be described.

  As shown in FIG. 13, an inkjet recording apparatus 102 includes a carriage 104 on which an inkjet recording head 112 is mounted, a main scanning mechanism 106 for scanning the carriage 104 in the main scanning direction X, and recording paper PE as a recording medium in the sub scanning direction. A sub-scanning mechanism 108 for scanning in Y, a maintenance station 110 for recovering the ejection characteristics of the inkjet recording head 112, and the like are included.

  The ink jet recording head 112 is mounted on the carriage 104 so that the nozzle plate 22 (see FIGS. 1 and 2) on which the nozzles 10 are formed faces the recording paper PE, and is moved in the main scanning direction X by the main scanning mechanism 106. Ink droplets Q (see FIG. 2B) are ejected onto the recording paper PE while being moved, and an image is recorded on a certain band region BE. In the case of the present embodiment, the Y direction shown in FIGS. 3, 6, 16, 17, and 19 to 25 is the conveyance direction (sub-scanning direction Y) of the recording paper PE, and the X direction is This corresponds to the main scanning X.

  When one movement in the main scanning direction X is completed, the recording paper PE is conveyed in the sub scanning direction Y by the sub scanning mechanism 108, and the next band region BE is moved while moving the carriage 104 in the main scanning direction X again. Record. By repeating these operations a plurality of times, image recording can be performed over the entire surface of the recording paper PE.

  In the above embodiment, recording is performed while the inkjet recording head 112 is scanned by the carriage 104, but the present invention is not limited to this. For example, as shown in FIG. 14, the inkjet recording head 112 has a configuration in which the nozzles 10 are arranged over the entire recording paper PE, and the inkjet recording head 112 is fixed and performs recording while conveying only the recording medium. An ink jet recording apparatus 302 called an FWA (Full Width Array) method may be used.

  The ink jet recording apparatus 302 forms an image on the entire surface of the recording paper PE simply by feeding the recording paper PE in the sub-scanning direction X without moving the ink jet recording head 112 in the main scanning direction Y, so that image formation is performed at high speed. be able to.

  In the case of this embodiment, the X direction shown in FIGS. 3, 6, 16, 17, and 19 to 25 is the recording paper PE conveyance direction (sub-scanning direction X), and the Y direction is Main scanning direction Y.

  Note that the inkjet recording head 112 has a row width of the nozzles 10 (in FIGS. 3 and 6) that can record a width that is the same as or larger than the maximum width W of the recording paper PE assumed in the inkjet recording apparatus 302. (Row width of the nozzle 10 in the Y direction).

  Further, although the ink jet recording head 112 is long in this way, as described above, the piezoelectric plates 204 are arranged in two rows in the Y direction (direction perpendicular to the conveyance direction (sub-scanning direction X) of the recording paper PE). Since the piezoelectric plates 204 are arranged side by side as described above, one piezoelectric plate 204 can be made small, so that it is elongated at a low cost.

  In addition, this invention is not limited to said embodiment.

  For example, in the above embodiment, one piezoelectric plate 204 is divided and a plurality of piezoelectric elements 36 are formed, but the present invention is not limited to this.

  For example, an inkjet recording head having the configuration described below may be used. In addition, the same code | symbol is attached | subjected to the member demonstrated in the said embodiment, and the overlapping description is abbreviate | omitted.

  As shown in FIG. 9, the inkjet recording head 512 can individually drive a laminated piezoelectric plate 538 in which a plurality of piezoelectric plates 504 are laminated and bonded to each pressure chamber 12, and the laminated piezoelectric plate 538 is used as a vibration plate. It is joined to the pressure chamber plate 32 without being interposed.

  The laminated piezoelectric plate 538 is configured by laminating a plurality of piezoelectric plates 504, internal negative electrode layers 542, and internal positive electrode layers 544 divided so as to correspond to the respective pressure chambers 12.

  The laminated piezoelectric plate 538 has an active portion 546 sandwiched between the internal negative electrode layer 542 and the internal positive electrode layer 544 and an inactive portion 548 that is not sandwiched. The active portion 546 is joined to the pressure chamber plate 32 so as to correspond to each pressure chamber 12.

  Next, the outline of the manufacturing method of the ink jet recording head 512 will be described below.

  First, a method for manufacturing the laminated piezoelectric plate 538 will be described.

  The piezoelectric plate 200 having a diameter D of about 12 mm described in the above embodiment is fired, and then cut into a square having a side H of about 7.0 mm. (See FIGS. 8A and 8B).

  At this time, unlike the above embodiment, as shown in FIG. 10, the internal positive electrode layer 544 and the electrode extraction portion 545 are formed simultaneously only on one surface of the piezoelectric plate 504. The piezoelectric plate 504 on which the internal positive electrode layer 544 and the electrode extraction portion 545 are formed is referred to as a green sheet 550. Further, in another piezoelectric plate 504, the internal negative electrode layer 542 and the electrode extraction portion 543 are simultaneously formed on only one surface. The piezoelectric plate 504 on which the internal negative electrode layer 542 and the electrode extraction portion 543 are formed is referred to as a green sheet 551.

  In FIG. 10, the internal negative electrode layer 542 is divided into six parts for the sake of clarity, but actually, the internal negative electrode layer 542 is divided into a larger number so as to correspond to the piezoelectric element 36 shown in the first embodiment. Yes.

  Then, a predetermined number of green sheets 550 and green sheets 551 are alternately stacked, and a piezoelectric plate 504 on which the internal positive electrode layer 544 and the internal negative electrode layer 542 are not formed is stacked on the top. And the whole is heat-pressed and degreasing, sintering, etc. are given.

  Next, as shown in FIG. 11, the external negative electrode 552 and the external positive electrode 554 are attached to the portions where the electrode extraction portions 543 and 545 are exposed. Then, it is immersed in an oil bath (not shown) filled with insulating oil such as silicon oil, and an electric field of about 2.5 kV is applied between the external negative electrode 552 and the external positive electrode 554 to perform polarization processing.

  As described above, the laminated piezoelectric plate 538 shown in FIG. 11 is produced.

  Then, in the same manner as described in FIG. 8C, the laminated piezoelectric plates 538 are foamed when the laminated piezoelectric plates 538 are arranged in two or more columns in the vertical and horizontal directions (4 columns × 2 rows in this embodiment) and heated at a predetermined temperature. Then, the adhesive is bonded to the intermediate holding member 208 via the heat-foamable adhesive film 206 having the property of greatly reducing the adhesive force.

  The stacked piezoelectric plates 538 are arranged in the same manner as in the above-described embodiment, with the stacked piezoelectric plates 538 divided into levels according to the amount of displacement with respect to a constant voltage.

  Subsequently, the steps up to FIGS. 7A and 7B described in the above embodiment are similar steps, but the diaphragm 34 joining step shown in FIG. 7C is omitted.

  The laminated piezoelectric plate 538 surface of the intermediate holding member 208 is bonded to the pressure chamber plate 32, the intermediate holding member 208 is heated to reduce the adhesive force of the thermally foamable adhesive film 206, and the intermediate holding member 208 is peeled off.

  The ink jet recording head 512 is provided with an electric circuit as shown in FIG. In this electric circuit, the negative electrode side of the drive power source 560 and the external negative electrode 552 of the multilayer piezoelectric plate 538 are grounded, and the positive electrode side of the drive power source 560 is connected to each external positive electrode of the multilayer piezoelectric plate 538 via the open / close switch 562. It is connected to the electrode 554.

  Next, the operation of the inkjet recording head 512 will be described.

  When each open / close switch 562 is closed by a control circuit (not shown), a drive voltage is applied between the internal negative electrode layer 542 and the internal positive electrode layer 544 located at a predetermined active portion 546 from the drive power supply 560. When the voltage is applied in this way, a bias voltage is applied to the piezoelectric plate 504 positioned between them, and the active portion 546 expands in the vertical direction as shown in FIG. 12 to pressurize the pressure chamber 12. Then, an ink droplet Q (see FIG. 2B) is ejected from the nozzle 10.

  Next, the operation of the ink jet recording head 512 of this embodiment will be described.

  Similar to the above-described embodiment, the laminated piezoelectric plate 538 is arranged by level according to the amount of displacement with respect to a constant voltage, and the same effect as the above-described embodiment is obtained. Furthermore, the following effects are also exhibited.

  As described so far, the ink jet recording head 512 can individually drive and pressurize the plurality of pressure chambers 12 with one laminated piezoelectric plate 538. Therefore, the structure is simplified, and there is no step of dividing into a plurality of piezoelectric elements 36 (see FIG. 8D). Further, the diaphragm 34 is not necessary. Therefore, a plurality of manufacturing steps can be omitted, and the material cost (diaphragm 34) can be reduced, so that the manufacturing cost is reduced.

  Further, since the piezoelectric element is divided into a plurality of piezoelectric elements, for example, there is no occurrence of defects such as breakage of the laminated piezoelectric plate 538 due to the influence of processing stress applied to the laminated piezoelectric plate 538 during machining such as sandblasting.

Furthermore, the laminated piezoelectric plate 538 formed by laminating and joining a plurality of small thin piezoelectric plates 504 can be driven at a low voltage. Therefore, in this embodiment, the laminated piezoelectric plate 538 formed by laminating and joining a plurality of piezoelectric plates 504 is used in the present embodiment, but the present invention is not limited to this. For example, one piezoelectric plate may be used so that it can be individually driven for each pressure chamber 12.

  Further, for example, in the first to third embodiments, one piezoelectric plate 204 is divided to form a piezoelectric element. However, a laminated piezoelectric plate in which a plurality of piezoelectric plates are stacked and joined is divided into piezoelectric elements. An element may be formed.

  For example, in the above-described embodiment, the case where the thickness of the fired piezoelectric plate 200 is not processed is described, but the present invention is not limited to this. Even when the piezoelectric plate is processed after firing, since the range of usable piezoelectric plates is wide, the processing accuracy may be rough, and the inkjet recording head can be manufactured at low cost.

  For example, the arrangement of the piezoelectric element group 252, the piezoelectric plate 204, and the laminated piezoelectric plate 538 may be other than the arrangement described in the above embodiment. Printing is possible with ink droplets ejected by piezoelectric elements of different levels of piezoelectric elements on the recording medium conveyance direction or a line perpendicular to the conveyance direction, or piezoelectric plates and multilayer piezoelectric plates are individually driven and discharged Printable with ink droplets, a group of piezoelectric elements, a piezoelectric plate, or a laminated piezoelectric plate is arranged, dots of different sizes are printed on the same line, and the difference in dots is not visually recognized, so the print quality It is good if you can maintain.

  The “recording medium” that is the target of image recording in the ink jet recording apparatus of the present invention includes a wide range of objects as long as the ink jet recording apparatus ejects ink droplets. In addition, the dot pattern on the recording medium obtained by attaching the ink droplets on the recording medium is widely included in the “image” or “recorded image” obtained by the recording apparatus of the present invention. Therefore, the ink jet recording apparatus of the present invention is not limited to that used for recording characters and images on recording paper. In addition, the recording medium includes recording paper, an OHP sheet, and the like. In addition, for example, a substrate on which a wiring pattern or the like is formed is included. The “image” includes not only general images (characters, pictures, photographs, etc.) but also the above-described wiring patterns, three-dimensional objects, organic thin films, and the like. The liquid to be discharged is not limited to colored ink. For example, production of a color filter for display performed by discharging colored ink on a polymer film or glass, formation of bumps for component mounting performed by discharging molten solder onto the substrate, and organic EL solution on the substrate For general liquid droplet ejecting devices intended for various industrial applications, such as the formation of EL display panels that are ejected onto the substrate and the formation of bumps for electrical mounting that are performed by ejecting molten solder onto the substrate. The ink jet recording head and the ink jet recording apparatus of the invention can be applied.

(A) is a cross-sectional perspective view showing a main part of the ink jet recording head according to the first embodiment of the present invention, and (B) is an enlarged view of a Z portion in (A). (A) is the figure which planarly viewed the ejector of the inkjet recording head which concerns on 1st Embodiment of this invention, (B) is sectional drawing of the BB cross section of (A). It is the figure which planarly viewed the ink jet recording head concerning a 1st embodiment of the present invention. It is the figure which planarly viewed the ejector group of the inkjet recording head which concerns on 1st Embodiment of this invention. FIG. 3 is an enlarged view of the ejector group of the ink jet recording head according to the first embodiment of the present invention viewed in plan. (A) is the figure which showed typically the nozzle arrangement | positioning of the inkjet recording head which concerns on 1st Embodiment of this invention, (B) is the figure which projected the nozzle to the X direction. It is the figure which showed typically the manufacturing process of the inkjet recording head which concerns on 1st Embodiment of this invention in order from (A) to (F). The manufacturing process of the piezoelectric plate of the inkjet recording head which concerns on 1st Embodiment of this invention, the process joined to an intermediate holding member, and the process divided | segmented into each piezoelectric element are shown typically in order from (A) to (D). It is a figure. It is sectional drawing of the principal part of the inkjet recording head which concerns on other embodiment of this invention. It is a figure which shows typically the green sheet of the inkjet recording head which concerns on other embodiment of this invention. It is a figure which shows typically the laminated piezoelectric plate of the inkjet recording head which concerns on other embodiment of this invention. It is explanatory drawing explaining operation | movement of the inkjet recording head which concerns on other embodiment of this invention. It is a figure which shows the inkjet recording device which uses either the inkjet recording head which concerns on 1st Embodiment of this invention from 4th Embodiment. It is a figure which shows the other inkjet recording device which uses either the inkjet recording head which concerns on 1st Embodiment of this invention from 4th Embodiment. It is the figure which showed the relationship between a piezoelectric element thickness and an exclusion volume, and showed the range which divides a piezoelectric plate into three steps. (A) schematically shows how to arrange the piezoelectric element groups of the ink jet recording head according to the first embodiment of the present invention, and (B) schematically shows a pattern in which dots are formed. (A) schematically shows another arrangement of the piezoelectric element groups of the ink jet recording head according to the first embodiment of the present invention, and (B) schematically shows a pattern in which dots are formed. It is the figure which showed the relationship between piezoelectric element thickness and exclusion volume, and showed the range which divides a piezoelectric plate into five steps. (A) schematically shows another arrangement of the piezoelectric element groups of the ink jet recording head according to the first embodiment of the present invention, and (B) schematically shows a pattern in which dots are formed. (A) schematically shows another arrangement of the piezoelectric element groups of the ink jet recording head according to the first embodiment of the present invention, and (B) schematically shows a pattern in which dots are formed. (A) is the figure which showed typically the nozzle arrangement | positioning of the inkjet recording head which concerns on 2nd Embodiment of this invention, (B) is the figure which projected the nozzle to the X direction. (A) schematically shows how to arrange the piezoelectric element groups of the inkjet recording head according to the second embodiment of the present invention, and (B) schematically shows a pattern in which dots are formed. (A) schematically shows another arrangement of the piezoelectric element groups of the ink jet recording head according to the second embodiment of the present invention, and (B) schematically shows a pattern in which dots are formed. (A) is the figure which showed typically the nozzle arrangement | positioning of the inkjet recording head which concerns on 3rd Embodiment of this invention, (B) is a figure which shows typically the pattern in which a dot is formed. (A) is the figure which showed typically the nozzle arrangement | positioning of the inkjet recording head which concerns on 4th Embodiment of this invention, (B) is a figure which shows typically the pattern in which a dot is formed. In a conventional ink jet recording head, (A) shows a dot pattern when only a level 2 piezoelectric plate is used, (B) shows a dot pattern when only a level 1 piezoelectric plate is used, (C) is a diagram showing a dot pattern when only a level 3 piezoelectric plate is used.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Nozzle 12 Pressure chamber 22 Nozzle plate 36 Piezoelectric element 52 Ejector group 102 Inkjet recording device 112 Inkjet recording head 152 Nozzle group 252 Piezoelectric element group 538 Multilayer piezoelectric plate 542 Internal negative electrode layer (electrode)
544 Internal positive electrode layer (electrode)
PE recording paper (recording medium)
Q ink drops

Claims (14)

A piezoelectric element group formed by dividing one piezoelectric plate or a laminated piezoelectric plate formed by laminating a plurality of the piezoelectric plates into a plurality of piezoelectric elements, and having a plurality of pressure chambers filled with ink. An ink jet recording head that individually discharges ink droplets from a nozzle communicating with the pressure chamber to a recording medium,
The piezoelectric element group is divided into levels according to the amount of displacement with respect to a constant voltage,
The piezoelectric element group is arranged such that printing can be performed with ink droplets ejected by the piezoelectric elements of the piezoelectric element group at different levels on a line in the conveyance direction of the recording medium or a direction orthogonal to the conveyance direction. Inkjet recording head. A plurality of pressure chambers filled with ink are stacked with one piezoelectric plate that can be individually driven for each pressure chamber, or a plurality of piezoelectric plates that can be individually driven for each pressure chamber. An ink jet recording head that individually pressurizes and depressurizes with a laminated piezoelectric plate joined, and discharges ink droplets from a nozzle communicating with the pressure chamber to a recording medium,
Leveling the piezoelectric plate or the laminated piezoelectric plate by the amount of displacement with respect to a certain voltage,
The recording plate can be printed with ink droplets ejected by individually driving the piezoelectric plate or the laminated piezoelectric plate at different levels on the conveyance direction of the recording medium or a line perpendicular to the conveyance direction. An ink jet recording head comprising a laminated piezoelectric plate. A piezoelectric element group formed by dividing one piezoelectric plate or a laminated piezoelectric plate formed by laminating and joining a plurality of the piezoelectric plates into a plurality of piezoelectric elements, and individually including a plurality of pressure chambers filled with ink. An ink jet recording head that discharges ink droplets from a nozzle communicating with the pressure chamber to the recording medium by applying pressure to the pressure chamber,
The piezoelectric element group is divided into levels according to the amount of displacement with respect to a constant voltage,
When the direction in which the recording medium is transported or the direction perpendicular to the transport direction is the row direction, and the direction intersecting the row direction is the column direction,
The piezoelectric element group is arranged in 2 rows and 2 columns or more,
A nozzle group is constituted by the nozzle that communicates with the pressure chamber to which the print pitch along the line in the row direction is P, the number of rows of the piezoelectric element group is L, and the piezoelectric element of the piezoelectric element group is pressurized or depressurized. When the nozzle pitch when the group is projected in the direction orthogonal to the row direction is M,
The nozzle groups are arranged shifted in the row direction so that P = M / L.
An ink jet recording head comprising at least one row composed of piezoelectric element groups of different levels. A plurality of pressure chambers filled with ink are stacked with one piezoelectric plate that can be individually driven for each pressure chamber, or a plurality of piezoelectric plates that can be individually driven for each pressure chamber. An inkjet recording head that individually pressurizes and depressurizes with a laminated piezoelectric plate joined, and ejects ink droplets from a nozzle communicating with the pressure chamber onto a recording medium,
Leveling the piezoelectric plate or the laminated piezoelectric plate by the amount of displacement with respect to a certain voltage,
When the direction in which the recording medium is transported or the direction perpendicular to the transport direction is the row direction, and the direction intersecting the row direction is the column direction,
The piezoelectric plate or the laminated piezoelectric plate is arranged in two rows and two columns or more,
The nozzle that communicates with the pressure chamber to which the printing pitch along the line in the row direction is P, the number of rows of the piezoelectric plate or the laminated piezoelectric plate is L, and the piezoelectric plate or the laminated piezoelectric plate individually pressurizes and depressurizes. When the nozzle pitch is M and the nozzle pitch when the nozzle group is configured and projected in the direction orthogonal to the row direction is
The nozzle groups are arranged shifted in the row direction so that P = M / L.
An ink jet recording head comprising at least one row composed of different levels of the piezoelectric plates or the laminated piezoelectric plates.   The piezoelectric plate or the laminated piezoelectric plate can be individually driven for each of the pressure chambers by an electrode pattern formed on the piezoelectric plate. Inkjet recording head.   The piezoelectric element group of the different level, the piezoelectric plate, or the laminated piezoelectric plate, the piezoelectric element group in a row composed of the piezoelectric plate group, the piezoelectric plate, or the average value of the deformation amount of the laminated piezoelectric plate is divided into levels. 6. The ink jet recording head according to claim 3, wherein a center value of the deformation amount substantially coincides with the center value of the deformation amount.   The piezoelectric element group, the piezoelectric plate, or the laminated piezoelectric plate in a row composed of the piezoelectric element group, the piezoelectric plate, or the laminated piezoelectric plate at different levels, The inkjet device according to any one of claims 3 to 6, wherein the piezoelectric element group, the piezoelectric plate, or the laminated piezoelectric plate having a high deformation amount and a low deformation amount are alternately arranged. Recording head.   The piezoelectric element group, the piezoelectric plate, or the century layer piezoelectric plate in a row composed of the piezoelectric element group, the piezoelectric plate, or the laminated piezoelectric plate of the different levels is composed of two piezoelectric elements adjacent in the column direction. 8. The deviation according to claim 3, wherein an average value of the deformation amount of the element group, the piezoelectric plate, or the laminated piezoelectric plate substantially coincides with a center value of the deformation amount divided into levels. 2. An ink jet recording head according to 1.   When projected in a direction orthogonal to the row direction at the boundary between the piezoelectric element group, the piezoelectric plate, or the laminated piezoelectric plate in adjacent columns, the piezoelectric element group, the piezoelectric plate, or the laminated piezoelectric plate in different rows The ink jet recording head according to claim 3, wherein the nozzles are arranged so that the nozzles overlap on the same line. When the number of rows of the piezoelectric element group, the piezoelectric plate, or the laminated piezoelectric plate is L, the row interval between the nozzle groups is T, the print pitch along the line in the row direction is P, and n is an arbitrary integer ,
T = ((n × P) + (P / L))
The inkjet recording head according to claim 3, wherein the relationship is as follows.   The inkjet recording head according to claim 1, wherein the displacement amount is defined by an electrostatic capacity of the piezoelectric plate.   The inkjet recording head according to claim 1, wherein the displacement is defined by the thickness of the piezoelectric plate.   The inkjet recording head according to any one of claims 1 to 12, wherein the piezoelectric plate is formed by firing and the thickness is not adjusted after firing.   An ink jet recording apparatus comprising the ink jet recording head according to claim 1.

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