Piezoelectric inkjet print head and printing system

Abstract

A piezoelectric inkjet print head includes a piezoelectric inkjet printing device, a manifold, a U-shaped flexible wiring board and an interconnection board. The piezoelectric inkjet printing device includes a piezoelectric plate and a substrate with at least one row of droplet ejectors; an ink inlet; signal lines leading to corresponding signal input pads; and ground lines leading to at least one return pad. The manifold is fluidly connected to the ink inlet. The U-shaped flexible wiring board includes a device connection area and two legs extending outward from the device connection area. The two legs include signal connection lines and at least one ground connection line. The interconnection board is located between the device connection area of ​​the U-shaped flexible wiring board and the contact layer of the piezoelectric inkjet printing device, and its contact layer includes signal input pads and at least one return pad.

Description

Technical Field

[0001] The present invention belongs to the field of piezoelectric inkjet printing, and more specifically relates to the structure of a piezoelectric inkjet print head package. Background Art

[0002] Inkjet printing is usually done with drop-on-demand or continuous inkjet printing. In drop-on-demand printing, droplets are ejected onto a recording medium using a droplet ejector with a booster (e.g., thermal or piezoelectric) driver. The driver is selectively activated to form and eject a flying droplet of ink that passes through the space between the print head and the recording medium and impacts the recording medium. The formation of the printed image is achieved by controlling the formation of each droplet as required to print the desired image. The desired image may include any dot pattern corresponding to the image data. It may include a graphic or text image. If appropriate ink is used, it may also include a dot pattern or a three-dimensional structure for printing a practical functional device. The ink may include a colored ink, such as cyan, magenta, yellow, or black. Alternatively, the ink may include a conductive material, a dielectric material, a magnetic material, or a semiconductor material for functional printing. The ink may also include biological, chemical, or medical materials.

[0003] During droplet ejection, the motion of the recording medium relative to the printhead can be: keeping the printhead stationary while the recording medium advances past the printhead during droplet ejection; or keeping the recording medium stationary while the printhead moves. The former motion configuration is suitable if the array of droplet ejectors on the printhead can cover the entire print area of ​​interest across the width of the recording medium. Such printheads are sometimes referred to as page width printheads. The second type of printer configuration is a carriage printer, in which the printhead droplet ejector array is smaller than the extent of the print area of ​​interest on the recording medium, and the printhead is mounted on a carriage. In a carriage printer, the recording medium advances a given distance in the direction of media advance and then stops. While the recording medium stops, the carriage carries the printhead whose nozzles are ejecting droplets in a carriage scanning direction that is substantially perpendicular to the media advance direction. After the printhead mounted on the carriage traverses the print medium while printing a strip of image, the recording medium is advanced; the direction of motion of the carriage is then reversed; the printed image is thus formed strip by strip.

[0004] The drop ejector in a drop-on-demand inkjet printhead includes a pressure chamber with an ink inlet to supply ink to the pressure chamber and a nozzle orifice for ejecting ink droplets out of the pressure chamber. In a piezoelectric inkjet printing device, one wall of the pressure chamber includes a piezoelectric element, which, when a voltage pulse is applied, causes the wall to deflect and deform into the pressure chamber filled with ink, thereby forcing the ink through the nozzle orifice. Piezoelectric inkjets have significant advantages in chemical compatibility and ink jettability with a wide variety of inks (including aqueous inks, solvent-based inks, and UV-curable inks), and the ability to eject ink droplets of different sizes by modifying the electrical pulse.

[0005] There are still technical challenges to be solved for piezoelectric inkjet printing devices. Because the amount of piezoelectric displacement per volt of voltage is small, the piezoelectric chamber wall area must be much larger than the nozzle area in order to eject a useful amount of droplets, so each droplet ejector is relatively large. The width of each droplet ejector in a row of droplet ejectors is limited by the spacing between the nozzles in that row. As a result, the length dimension of the pressure chamber is usually much larger than the width dimension. Printing applications that require high resolution and high-volume printing require a large number of droplet ejector arrays with closely arranged nozzles. By properly timing the ejection of each row of droplet ejectors, the staggered rows of nozzles can produce close-range dots on the recording medium. However, for many staggered rows, the size of the piezoelectric inkjet printing device becomes very large.

[0006] Another challenge is that, unlike thermal inkjet devices, which often include integrated logic and drive electronics to reduce the number of device pins, piezoelectric inkjet devices typically have multiple individual pins per drop ejector that need to be connected to a driver circuit board. In order to independently apply voltage to the piezoelectric element across each drop ejector to eject a drop when needed, each drop ejector needs to be connected to two electrodes. These two types of electrodes are sometimes referred to as positive and negative electrodes, or as individual and common electrodes.

[0007] Some types of piezoelectric inkjet printing devices are constructed with two types of electrodes on opposite surfaces of the piezoelectric element. In order to connect the piezoelectric inkjet printing device to a drive circuit board, it is advantageous to arrange the two types of electrodes on the same outer surface of the piezoelectric inkjet printing device.

[0008] U.S. Patent No. 5,255,016 discloses a piezoelectric inkjet printing device in which positive and negative comb electrodes are formed on the outer surface of a piezoelectric plate. The teeth of the comb extend across the entire width of the drop ejector, at least in certain areas. A portion of the positive electrode extends along one edge of the piezoelectric plate, and a portion of the negative electrode extends along the opposite edge of the piezoelectric plate. Each drop ejector has a separate piezoelectric plate, which makes it difficult to manufacture large arrays of closely spaced drop ejectors.

[0009] U.S. Patent No. 6,243,114 discloses a piezoelectric inkjet printing device, wherein the common electrode on the outer surface of the piezoelectric plate is in a comb shape, one electrode tooth of which extends along each side wall of the pressure chamber, and the central common electrode tooth extends along the length of the pressure chamber. Two single electrodes extend along the length of the pressure chamber on both sides of the central common electrode tooth.

[0010] U.S. Patent No. 5,640,184 discloses a piezoelectric inkjet printing device in which pressure chambers of a row of nozzles extend alternately in opposite directions from the row of nozzles. A common electrode on the surface of a piezoelectric plate extends along the row of nozzles and has electrode teeth extending alternately in opposite directions on the side walls of the pressure chambers. Interlaced between the electrode teeth of the common electrode are spaced arrays of individual electrodes that are located directly above the pressure chambers. When a voltage is applied to the individual electrodes, the piezoelectric plate mechanically deforms in a shear mode to recess into the corresponding pressure chamber, thereby causing the ejection of ink droplets.

[0011] Chinese patent application No. 107344453A discloses a piezoelectric inkjet printing device, such as Figure 1 and Figure 2 shown. Figure 1 and 2 Taken from '453, reproduced for clarity in Figure 1 Some additional labels are added. The substrate 100 includes a first side 101, and a row of pressure chambers 110 are distributed on the first side 101. Each pressure chamber 110 is bounded by side walls 161 and 162. A channel 130 leads from the pressure chamber 110 to a nozzle 132 arranged on the second side 102 of the substrate 100. The width of the pressure chamber 110 between the side walls 161 and 162 is W. An ink groove 120 is fluidly connected to one end of each pressure chamber 110 to provide ink to them. A damping structure 140 including a plurality of pillars 141 is arranged in each pressure chamber 110, between the ink groove 120 and the channel 130. The drive cover plate 200 includes a piezoelectric plate 210, which can be made of, for example, lead zirconate titanate piezoelectric ceramic (PZT) material. The first surface 211 of the piezoelectric plate 210 is bonded to the first side 101 of the substrate 100. An electrode layer 220 is disposed on the outer second surface 212 of the piezoelectric plate 210. The electrode layer 220 includes a positive electrode 221 disposed along the length of the pressure chamber 110; and a negative electrode 222 disposed along the length of the side walls 161 and 162 between the pressure chambers 110. An ink inlet 230 passes through the piezoelectric plate 210 to introduce ink from an external ink supply source to the ink tank 120 in the substrate 100. The nozzle 132 extends outward from the flow channel 131 in the silicon material layer 310, passes through the oxide layer 320 and the nozzle layer 330 ( Figure 2 ).

[0012] In order to interface with the printer in a space efficient manner, what is needed is a print head package that is capable of making electrical connections to the many signal input and ground return pads on the electro-inkjet printing device, as well as fluid connections. Summary of the invention

[0013] According to one aspect of the present invention, a piezoelectric inkjet print head includes a piezoelectric inkjet printing device, a manifold, a U-shaped flexible wiring board and an interconnection board. The piezoelectric inkjet printing device includes a piezoelectric plate and a substrate with at least one row of droplet ejector arrays, so that each row of droplet ejector arrays is aligned along the row direction. Each droplet ejector includes a pressure chamber and a nozzle connected to the pressure chamber in a fluid. The piezoelectric plate has a first surface adjacent to the pressure chamber and an outer second surface opposite to the first surface. The piezoelectric inkjet printing device includes at least one ink inlet to provide ink to the pressure chamber. A signal line corresponding to each droplet ejector leads to a corresponding signal input pad. At least one common general ground line is arranged along the row direction. The common general ground line is connected to the ground line arranged between adjacent pressure chambers. At least one common general ground line leads to at least one return ground pad. The manifold is fluidly connected to at least one ink inlet. The U-shaped flexible wiring board includes a device connection area and two legs, and the two legs extend outward from the device connection area. The device connection area includes a plurality of signal connection pads and at least one ground connection pad, each signal connection pad faces a corresponding signal input pad, and each ground connection pad faces a corresponding ground return pad. The two legs include a plurality of signal connection lines and at least one ground connection line, each signal connection line extends outward from a corresponding signal connection pad, and each ground connection line extends outward from a corresponding ground connection pad. The interconnection board is arranged between the device connection area of ​​the U-shaped flexible wiring board and the contact layer of the piezoelectric inkjet printing device, and the contact layer of the piezoelectric inkjet printing device includes a signal input pad and at least one ground return pad.

[0014] According to another aspect of the present invention, a piezoelectric inkjet printing system includes a piezoelectric inkjet print head, an image data source, a controller, an electric pulse source and a logic circuit board. The piezoelectric inkjet printing device includes a piezoelectric plate and a substrate with at least one row of droplet ejectors, so that each row of droplet ejectors is aligned along the row direction. Each droplet ejector includes a pressure chamber and a nozzle connected to the pressure chamber in a fluid. The piezoelectric plate has a first surface adjacent to the pressure chamber and an outer second surface opposite to the first surface. The piezoelectric inkjet printing device includes at least one ink inlet to provide ink to the pressure chamber. A signal line corresponding to each droplet ejector leads to a corresponding signal input board. At least one common total ground line is arranged along the row direction. The common total ground line is connected to the ground line arranged between adjacent pressure chambers. The at least one common total ground line leads to at least one return pad. The manifold is fluidly connected to at least one ink inlet. The U-shaped flexible wiring board includes a device connection area and two legs, and the two legs extend outward from the device connection area. The device connection area includes a plurality of signal connection pads and at least one ground connection pad, each signal connection pad faces a corresponding signal input pad, and each ground connection pad faces a corresponding ground return pad. The two legs include a plurality of signal connection lines and at least one ground connection line, each signal connection line extends outward from a corresponding signal connection pad, and each ground connection line extends outward from a corresponding ground connection pad. The interconnection board is arranged between the device connection area of ​​the U-shaped flexible wiring board and the contact layer of the piezoelectric inkjet printing device, and the contact layer of the piezoelectric inkjet printing device includes a signal input pad and at least one ground return pad. The logic circuit board is connected to the U-shaped flexible wiring board.

[0015] An advantage of the present invention is that the printhead package facilitates electrical connections to a number of signal input pads and ground return pads on a piezoelectric inkjet printing device, regardless of whether the electrodes are located on the outer or inner surface of the piezoelectric plate. The printhead package has the further advantage that the printhead electrical and fluid connections are sufficiently similar for these different types of piezoelectric inkjet printing devices that all four types of piezoelectric inkjet printing devices can be used interchangeably in the same printer with little or no change in printer operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 An exploded schematic diagram showing a prior art piezoelectric drop ejector array configuration;

[0017] Figure 2 Shows Figure 1 A cross section of a single droplet ejector of the type shown;

[0018] Figure 3A A cross section of a portion of a piezoelectric inkjet printing device showing electrodes on the outer surface of a piezoelectric plate;

[0019] Figure 3BA cross section of a portion of a piezoelectric inkjet printing device showing electrodes on the inner surface of a piezoelectric plate;

[0020] Figure 4 Shows Figure 3A and 3B A top view of a piezoelectric inkjet printing device;

[0021] Figure 5 A cross section of a portion of another piezoelectric inkjet printing device having electrodes on the inner surface of a piezoelectric plate is shown;

[0022] Figure 6 Shows Figure 5 A top view of a piezoelectric inkjet printing device;

[0023] Figure 7 A cross section of a portion of yet another piezoelectric inkjet printing device having electrodes on the inner surface of a piezoelectric plate is shown;

[0024] Figure 8 Shows Figure 7 A top view of a piezoelectric inkjet printing device;

[0025] Fig. 9 The occlusion layer with windows is shown;

[0026] Fig.10 Shows Figure 3A An example of electrical connection between a piezoelectric inkjet printing device and a U-shaped flexible wiring board;

[0027] Fig.11 Shows Figure 7 An example of electrical connection between a piezoelectric inkjet printing device and a U-shaped flexible wiring board;

[0028] Fig.12 A flexible terminal block is shown for use with Figure 3A , 3B , 5, and the piezoelectric inkjet printing device in 7 are electrically connected;

[0029] Fig.13 Shows Fig.12 A magnified view of the central area of ​​the flexible wiring board, rotated 90 degrees;

[0030] Fig.14 A schematic diagram of an inkjet printing system and a side view of a piezoelectric inkjet printing device are shown;

[0031] Fig.15 A side view of a piezoelectric inkjet print head from an inkjet face is shown according to one embodiment;

[0032] Fig.16 Shows Fig.15 A side view of the piezoelectric inkjet print head from the connection surface;

[0033] Fig.17 Shows Fig.15 Cross section of a medium voltage electro-inkjet print head;

[0034] Fig.18 An exploded schematic diagram showing connections to a piezoelectric inkjet printing device is shown;

[0035] Fig.19 Shows Fig.15 Side view of the manifold of a medium voltage electro-inkjet printhead;

[0036] Fig. 20 Shows Fig.19 The manifold in is bonded to the first plate;

[0037] Fig.21 Shows the bonding of a piezoelectric inkjet printed device to Fig. 20 on a first plate of the assembly;

[0038] Fig. 22 shows the second board bonded to Fig.21 on a first plate of the assembly;

[0039] Fig.23 shows the third board bonded to Fig. 22 on a second plate of the assembly;

[0040] Fig.24 shows a side view of a U-shaped flexible terminal block inserted into a slot in a manifold;

[0041] Fig.25 A schematic diagram showing a logic board that can be used to Fig.10 The U-shaped flexible wiring board in or 11 is connected to other components of the inkjet printing system.

[0042] The purpose of the drawings should be understood to be for illustrating the concepts of the present invention and may not be drawn to scale. Wherever possible, the same reference numerals are used to designate the same features that are common to the drawings. DETAILED DESCRIPTION

[0043] The present invention includes various combinations of the embodiments described herein. References to "a particular embodiment" and the like refer to features present in at least one embodiment of the present invention. Separate references to "one embodiment" or "a particular embodiment" and the like do not necessarily refer to the same one or more embodiments; however, unless explicitly stated or obvious to one skilled in the art, these embodiments are not mutually exclusive. When referring to "a method" or "multiple methods" and similar terms, the use of the singular or plural is non-restrictive. It is specifically noted that the use of "or" in this article has no exclusive meaning unless otherwise explicitly stated or required by the context. Words such as "above...", "below...", "above..." or "below..." are intended to describe the positional relationship between features located in different planes, but it should be understood that in one device orientation, a feature of one device is located "above" another feature, and if the device is turned upside down, the feature of the device will be located "below" another feature.

[0044] Figure 3A A portion of a piezoelectric inkjet printing device 10 is shown. Figure 4 The piezoelectric inkjet printing device 10 includes a piezoelectric plate 210, whose first surface 211 is structurally bonded to the first side 101 of the substrate 100 through a bonding layer 270. The bonding layer 270, for example, can be a polymer adhesive. The substrate 100 includes a pair of pressure chambers 111 and 112, and the pressure chambers extend outward from a central area. Each pressure chamber 111 and 112 includes a channel 130 leading to a nozzle 132, which is located in the nozzle layer 330 on the second side 102 of the substrate 100. An electrode layer 220 is located on the outer second surface 212 of the piezoelectric plate 210, and includes a signal line 251 extending on the pressure chambers 111 and 112.

[0045] Figure 3B A portion of a piezoelectric inkjet printing device 8 is shown. Figure 4 The piezoelectric inkjet printing device 8 has an electrode layer 240 on the inner first surface of the piezoelectric plate 210. The electrode layer includes a signal line, a signal input pad, at least one common ground line, and at least one return pad. An opening 218 is formed in the piezoelectric plate 210 to expose the signal input pad and at least one return pad for electrical connection with the piezoelectric inkjet printing device 8.

[0046] Refer to Figure 4, the piezoelectric inkjet printing device 8 or 10 includes a pair of staggered rows 181 and 182 of drop ejectors 150, each row aligned along the row direction 51. For example, each staggered row 181 and 182 may include a density of 100 drop ejectors 150 per inch, thereby providing a combined printing resolution of 200 dots per inch along the row direction 51. Each drop ejector 150 in the first row 181 includes a pressure chamber 111, and each drop ejector 150 in the second row 182 includes a pressure chamber 112. The nozzle orifice 132 is disposed near the first end 115 of the pressure chambers 111 and 112. Figure 4 In the illustrated example, ink is introduced directly into the ink inlet channel 121 of each drop ejector 150 from the edge of the substrate 100, where the edge of the substrate 100 extends along the row direction 51. The ink enters the pressure chamber 110 through the filter 146 and the restrictor 145, which are located near the second end 116 of the pressure chamber 110, where the second end 116 is the other end opposite the first end 115. The filter 146 may include a column similar to Figure 1 The restrictor 145 provides flow resistance (same as the filter 146), and when a drop of ink is ejected from the pressure chamber 111 or 112, the restrictor 145 helps to limit the flow of ink to the ink inlet 121, thereby directing more of the pressure generated by the deformation of the piezoelectric plate 210 to push the ink drop.

[0047] The signal line 251 is provided on each corresponding pressure chamber 111 and 112 and extends in a direction 52 perpendicular to the row direction 51. Figure 4 In the example shown, the signal line 251 is located at the center of the corresponding pressure chambers 111 and 112. Each signal line leads to a corresponding signal input pad 255. In the example where the drop ejectors 150 are arranged at 100 per inch in each row 181 and 182, the spacing between the nozzle holes 132 and their corresponding signal input pads 255 along the row direction 51 will be 0.010 inches each. The ground line 261 is arranged on the first side wall 161 and the second side wall 162 of the pressure chambers 111 and 112 and is aligned along the side walls. The ground line is generally located in the middle position between the corresponding pressure chambers and extends in a direction 52 perpendicular to the row direction 51. The ground line 261 leads to a common total ground line 264 extending along the row direction 51, and the common total ground line 264 leads to a return ground pad 265.

[0048] Figure 5 A portion of a piezoelectric inkjet printing device 9 is shown. Figure 6The piezoelectric inkjet printing device 9 includes a substrate 100, an array of at least one drop ejector 150 row 181 or 182, a piezoelectric plate 210, a bonding layer 270, a first electrode layer 240, a second electrode layer 740 and at least one common ground line 264 or 764. Also refer to Figure 6 , the droplet ejectors 150 in each row 181 and 182 are aligned along the row direction 51. For example, each staggered row 181 and 182 may include a density of 100 droplet ejectors 150 per inch, thereby providing a combined printing resolution of 200 dots per inch along the row direction 51. Each droplet ejector 150 includes a pressure chamber 111 or 112 disposed on the first side 101 of the substrate 100. The pressure chamber is bounded by a first side wall 161 and a second side wall 162. Each droplet ejector 150 also includes a nozzle 132 disposed in a nozzle layer 330, which is located on a second side 102 opposite to the first side 101 of the substrate 100. In Figure 6 In the example shown, ink is introduced into the ink channel 121 of each drop ejector 150 directly from an edge of the substrate 100 , which extends along the row direction 51 .

[0049] Piezoelectric plate 210 ( Figure 5 ) has a first surface 211 adjacent to the first surface 101 of the substrate 100 and an outer second surface 212 opposite to the first surface 211. The first and second groups of conductive vias extend from the first surface 211 to the outer second surface 212. The first electrode layer 240 is located on the first surface 211 of the piezoelectric plate. The first electrode layer 240 includes a first signal line 251 corresponding to each pressure chamber 111 or 112. Each first signal line 251 is connected to a signal via 775 in the corresponding first group of conductive vias. The first electrode layer 240 also includes a ground line 261 located on the side walls 161 and 162 of each pressure chamber 111 and 112. The ground line 261 is connected to at least one corresponding ground via 784 in the second group of conductive vias. The second electrode layer 740 is located on the second surface 212 of the piezoelectric plate 210. The second electrode layer 740 includes a second signal line 751 and a signal input pad 755 corresponding to each first signal line 251, wherein each signal input pad 755 is connected to a signal through hole 775 of the corresponding first conductive through hole group through a second signal line 751. Figure 6The second electrode layer 740 further includes at least one return pad 765 connected to a plurality of ground vias 784 in the second group of conductive vias. At least one return pad 765 is connected to at least one common ground line 264 or 764. The bonding layer 270 is located between the first electrode layer 240 and the first side 101 of the substrate 100. The bonding layer 270 bonds the piezoelectric plate 210 to the first side 101 of the substrate 100. In addition, the bonding layer 270 isolates the ink in the pressure chambers 111 and 112 from the wires and the piezoelectric plate 210.

[0050] Figure 7 A portion of the piezoelectric inkjet printing device 11 is shown by Figure 8 The cross section of the dotted line 7-7. Also refer to Figure 8 The piezoelectric inkjet printing device 11 includes a substrate 100, a first row 181 and a second row 182 of droplet ejectors 150, a piezoelectric plate 210, a bonding layer 270, a first electrode layer 240, a second electrode layer 440, and at least one common ground line 464. The droplet ejectors 150 in each row 181 and 182 are aligned along the row direction 51. For example, each staggered row 181 and 182 may include a density of 100 droplet ejectors 150 per inch, thereby providing a combined printing resolution of 200 dots per inch along the row direction 51. Each droplet ejector 150 includes a pressure chamber 111 or 112 disposed on the first side 101 of the substrate 100. The pressure chamber is bounded by a first sidewall 161 and a second sidewall 162. Each droplet ejector 150 further includes a nozzle 132 disposed in a nozzle layer 330, which is located on the second surface 102 opposite to the first surface 101 of the substrate 100. Figure 8 In the example shown, ink is introduced into the ink inlet channel 121 of each drop ejector 150 directly from an edge of the substrate 100 , which extends along the row direction 51 .

[0051] Piezoelectric plate 210( Figure 7) has a first surface 211 close to the first surface 101 of the substrate 100. The first electrode layer 240 is located on the first surface 211 of the piezoelectric plate. The first electrode layer 240 includes a first signal line 251 corresponding to each pressure chamber 111 and 112. Each first signal line 251 leads to a corresponding signal line welding node 475. The first electrode layer 240 also includes a ground line 261 located on the sidewalls 161 and 162 of each pressure chamber 111 and 112. The ground line 261 is electrically connected to the ground wire welding node 485. The bonding layer 270 is located between the first electrode layer 240 and the first surface 101 of the substrate 100, and has a bonding layer window 275 corresponding to each signal line welding node 475 and each ground wire welding node 485. The second electrode layer 440 is located on the first surface 101 of the substrate 100. The second electrode layer 440 includes a second signal line 451 corresponding to each first signal line 251. Each second signal line 451 leads to a corresponding signal input pad 455. In the example where the drop ejectors 150 are arranged at 100 per inch in each row 181 and 182, the spacing between the nozzles 132 and their corresponding signal input pads 255 along the row direction 51 will be 0.010 inches. The first signal line 251 is connected to the corresponding second signal line 451 through the signal line welding node 475. The second electrode layer 440 also includes a ground line 461. Each ground line 461 is connected to a corresponding one of the ground lines 261 through the ground line welding node 485. The second electrode layer 440 also includes at least one return ground pad 465, which is electrically connected to the plurality of ground lines 461 through at least one common general ground line 464. A portion of the piezoelectric plate 210 is removed to form an opening 218 to expose the pads for electrical connection of the assembled piezoelectric inkjet printing device.

[0052] like Fig. 9 As shown in the top view, in order to Figure 3A , 3B , and 4) provide a more reliable and short-circuit-free electrical interconnection, a masking layer 280 can be disposed on the electrode layer 220 or 240 on the second surface 212 or the first surface 211 of the piezoelectric plate 210 thereof, so that the masking layer window 281 is disposed on the signal input pad 255, and the masking layer window 282 is disposed on the return pad 265, exposing the pad for electrical interconnection. Similarly, for the piezoelectric inkjet printing device 9 ( Figure 5 and 6 ), a masking layer 280 can be disposed on the electrode layer 740 on the second surface 212 of the piezoelectric plate 210 thereof, so that the masking layer window 281 is disposed on the signal input pad 755, and the masking layer window 282 is disposed on the return pad 765, exposing the pad for electrical interconnection. Similarly, for the piezoelectric inkjet printing device 11 ( Figure 7 and 8), a masking layer 280 may be disposed on the electrode layer 440 on the first side 101 of the substrate 100 thereof, so that the masking layer window 281 is located on the signal input pad 455, and the masking layer window 282 is disposed on the return pad 465, exposing the pad for electrical interconnection.

[0053] Fig.10 Shown Figure 3A and 4 The cross section of the electrical connection of the piezoelectric inkjet printing device 10 shown in FIG. In the piezoelectric printing device 10, the signal input pad 255 and the at least one return pad 265 ( Figure 4 ) is included in the electrode layer 220 disposed on the second surface 212 of the piezoelectric plate. Here, the layer including the signal input pad and the return pad is also called the contact layer. The U-shaped flexible wiring board 500 includes a device connection area 505 on its base, which has a plurality of signal connection pads 530 and at least one ground connection pad 540 ( Fig.13 ). Each signal connection pad 530 faces a corresponding signal input pad 255. In a similar manner, each ground connection pad 540 ( Fig.13 ) facing a corresponding return pad 265 ( Figure 4 A pair of legs (a first leg 510 and a second leg 520) of the U-shaped flexible wiring board 500 extend outward from the device connection region 505, as shown below. Fig.12 and 13 A detailed description is given. An interconnection board 590 is arranged between the device connection area 505 and the contact layer (electrode layer 220), and the contact layer includes a signal input pad 255 and a return pad 265. The interconnection board 590 may include an anisotropic conductive film, which can be cured between the device connection area 505 and the signal input pad 255 and the return pad 265. The anisotropic conductive film provides electrical connection along the longitudinal conductivity through the thickness of the interconnection board 590, but does not provide conductivity along the lateral direction of the interconnection board 590, thereby avoiding short circuits. The interconnection board 590 is flexible before curing and can pass through the masking layer windows 281 and 282 ( Fig. 9 ) is pressed into contact with the contact layer. In the piezoelectric inkjet printing device 9 ( Figure 5 and 6 ) on the outer second surface 212 of the piezoelectric plate, the signal input pad 755 and the return pad 765 can be electrically connected in a similar manner.

[0054] Fig.11 illustrate Figure 7 and 8 The cross-sectional view of the electrical connection of the piezoelectric inkjet printing device 11 is shown. In the piezoelectric inkjet printing device 11, the signal input pad 455 and at least one return pad 465 ( Figure 8) is included in the second electrode layer 440 (i.e., the contact layer) on the first surface 101 of the substrate 100. The U-shaped flexible wiring board 500 includes a device connection area 505 on its base, which has a plurality of signal connection pads 530 and at least one ground connection pad 540 ( Fig.13 ). Each signal connection pad 530 faces the corresponding signal input pad 455. In a similar manner, each ground connection pad 540 ( Fig.13 ) facing a corresponding return pad 465 ( Figure 8 ). The device connection area 505 is narrow enough to pass through the opening 218 of the piezoelectric plate 210 so as to be connected to the signal input pad 455 and the at least one return pad 465. A pair of legs (a first leg 510 and a second leg 520) of the U-shaped flexible wiring board 500 extend outward from the device connection area 505. An interconnection board 590, such as an anisotropic conductive film, is disposed between the device connection area 505 and the contact layer (the second electrode layer 440), which includes the signal input pad 455 and the return pad 465. The interconnection board 590 is flexible before curing and can pass through the opening 218 in the piezoelectric plate 210 and the masking layer windows 281 and 282 ( Fig. 9 ) is pressed into contact with the contact layer. In the piezoelectric inkjet printing device 8 ( Figure 3B and 4 ) on the first surface 211 of the piezoelectric plate, the signal input pad 255 and the return pad 265 can be electrically interconnected in a similar manner.

[0055] Fig.12 FIG. 5 shows an example of the flexible wiring board 500 before being folded into a U shape. Fig.12 5 , the first leg 510 extends to the left and the second leg 520 extends to the right. The first leg 510 is bifurcated into a first portion 511 and a second portion 512, which are separated from each other by a notch 515 for independent bending. Similarly, the second leg 520 is bifurcated into a first portion 521 and a second portion 522, which are separated from each other by a notch 525. Each leg 510 and 520 includes signal connection lines 531, which pass to a signal connector plate 535 in a connector connection area 550. Similarly, each leg 510 and 520 includes ground connection lines 541, which pass to a ground connector plate 545 in the connector connection area 550. There are four connector connection areas 550 that can be used for connector installation, as described below, each portion of each leg 510 and 520 has a connector.

[0056] Fig.13 An enlarged view of the central area 508 of the flexible wiring board 500 is shown and rotated 90 degrees in a counterclockwise direction. Fig.13In the example shown, the first and second portions 511 and 512 of the first leg 510 each have 90 signal connection lines 531, and the first and second portions 521 and 522 of the second leg 520 also each have 90 signal connection lines 531. This structure is suitable for connecting a piezoelectric inkjet printing device 8 or 10 (with a total of 360 drop ejectors 150) Figure 4 ), wherein half of the droplet ejectors are arranged in the first row 181 and the other half of the droplet ejectors are arranged in the second row 182. This structure is also applicable to a piezoelectric inkjet printing device 9 (connected to a total of 360 droplet ejectors 150) Figure 6 ) or a piezoelectric inkjet printing device 11 ( Figure 8 ), wherein half of the droplet ejectors are arranged in the first row 181 and the other half of the droplet ejectors are arranged in the second row 182. Fig.13 As shown, each signal connection line 531 extends outward from a corresponding signal connection pad 530, and each ground connection line 541 extends outward from a corresponding ground connection pad 540. Each of the four connector connection areas includes 90 signal connection pads 530 and a plurality of ground connection pads 540.

[0057] for Figure 4 In the piezoelectric inkjet printing device 8 or 10 shown, the signal connection pad 530 in the first leg 510 can be connected to the signal input pad 255 of the droplet ejector 150 in the corresponding first row 181, and the signal connection pad 530 in the second leg 520 can be connected to the signal input pad 255 of the droplet ejector 150 in the corresponding second row 182.

[0058] for Figure 6 In the piezoelectric printing device 9 shown, the signal connection pad 530 in the first leg 510 can be connected to the signal input pad 755 of the droplet ejector 150 in the corresponding first row 181, and the signal connection pad 530 in the second leg 520 can be connected to the signal input pad 755 of the droplet ejector 150 in the corresponding second row 182.

[0059] for Figure 8 In the piezoelectric printing device 11 shown, the signal connection pad 530 in the first leg 510 can be connected to the signal input pad 455 of the droplet ejector 150 in the corresponding first row 181, and the signal connection pad 530 in the second leg 520 can be connected to the signal input pad 455 of the droplet ejector 150 in the corresponding second row 182.

[0060] Fig.14A schematic diagram of an inkjet printing system 1 is shown, with a partial perspective view of a piezoelectric inkjet printing device 8 or 9 or 10 or 11. An image data source 12 provides an image data signal to a controller 14, which translates its image data signal into instructions for ejecting ink droplets. The controller 14 includes an image processing unit 13 for rendering an image. The term "image" is herein intended to include any dot pattern determined by the image data. It may include a graphic or text image. If appropriate ink is used, it may also include a dot pattern or a three-dimensional structure for printing a functional device. The controller 14 also includes a transmission control unit 17 and an ejection control unit 18, which are respectively used to control the transmission mechanism 16 and eject ink droplets to print the dot pattern corresponding to the image data onto the recording medium 60. The controller 14 sends an output signal to an electric pulse source 15, which sends an electric pulse waveform to an inkjet print head 5, whose inkjet print head includes a piezoelectric inkjet printing device 8 or 9 or 10 or 11. The transmission mechanism 16 provides relative movement between the inkjet print head 5 and the recording medium 60 along a direction 52. In some embodiments, the drive mechanism 16 is configured to move the recording medium 60 in the direction 52 while the print head 5 is stationary. Alternatively, the drive mechanism 16 can move the print head 5, for example on a sled, back and forth across the stationary recording medium 60. Since piezoelectric inkjet printing devices generally do not include integrated logic circuitry, a logic circuit board 30 helps facilitate electrical connections between the controller 14 and the inkjet print head 5, as described below. Fig.25 This is particularly useful in a sled printer to reduce the number of leads that need to be moved to facilitate the forward and backward movement of the print head 5 relative to the recording medium 60. Various recording media 60 for inkjet printing include paper, plastics, and textiles. In a 3D inkjet printer, the recording medium 60 includes a flat building platform and a thin layer of powdered material. In addition, in various embodiments, the recording medium 60 can be input in single sheets from an input tray or in rolls from a roll.

[0061] The piezoelectric inkjet printing device 8 or 9 or 10 or 11 includes at least one pair of rows 181 and 182 ( Figure 4 , 6 , and 8). For simplicity, Fig.14 The location of the drop ejector 150 is indicated by the circular orifice 132, which is formed in the orifice layer 330. The rows 181 and 182 extend along the row direction 51 and are staggered relative to each other to provide a higher printing resolution. Fig.14In the example shown, the substrate 100 of the piezoelectric inkjet printing device includes a first edge 103 and a second edge 104, both of which extend along the row direction 51. An ink inlet 235 is provided at least in one of the first and second edges 103 and 104. For example, the ink inlet 235 in the first edge 103 can provide ink for the row 181 of the drop ejectors 150, and the ink inlet 235 in the second edge 104 can provide ink for the row 182 of the drop ejectors 150.

[0062] The ink flows through the ink source 190, through at least one ink inlet port 235, and into the ink inlet 121 ( Figure 4 , 6 and 8), provide ink to the piezoelectric inkjet printing device 8 or 9 or 10 or 11. In this article, ink source 190 is broadly understood to include any substance that can be ejected from the ejector of the inkjet print head. Ink source 190 can include color inks, such as cyan, magenta, yellow, or black. Alternatively, ink source 190 can include conductive materials, dielectric materials, magnetic materials, or semiconductor materials for printing functional devices. Ink source 190 can also include biological, chemical, medical or other materials. Piezoelectric inkjet printing devices are very suitable for ejecting various ink types, including solvent inks, UV curable inks, and aqueous inks.

[0063] Fig.15 A side view of a piezoelectric inkjet print head 5 is shown, including a piezoelectric inkjet printing device 8 or 9 or 10 or 11 and a print head packaging component, such as a U-shaped flexible wiring board 500, connectors 561-564 (see also Fig.18 ), manifold 610, ink tube connector 630 (also referred to herein as ink interface), first board 660, second board 670, and third board 680. The print head package assembly facilitates the connection of the piezoelectric inkjet printing device 8 or 9 or 10 or 11 with the rest of the inkjet printing system 1 ( Fig.14 ) electrical and fluid connections, and provide mechanical and environmental protection and mounting features for the piezoelectric inkjet printing device. Figure 4 , 6 , 8, 10 and 11, the U-shaped flexible wiring board 500 realizes high-density electrical connection to the signal input pads 255 or 455 or 755 (for example, the pitch is 0.010 inches) through the interconnection board 590. By dividing a quarter of the signal connection line 531 and the ground connection line 541 to four connector connection areas 550 ( Fig.12 ) on each of the connectors 561-564 ( Fig.15 and 18) installation. Through a connector at each of the first portion 511 and the second portion 512 of the first leg 510, and a connector at each of the first portion 521 and the second portion 522 of the second leg 520, these connectors can be connected to the logic circuit board 30 ( Fig.14 ) corresponding to the individual circuit board connectors 31-34, refer to the following Fig.25 No excessive force is required during installation. Fig.15 In the example shown, connectors 561-564 are mounted on the inner side of the U-shaped flexible wiring board 500, whereby the connector 561 on the first portion 511 of the first leg 510 and the connector 563 on the first portion 521 of the second leg 520 face each other and are offset in position (the connector 562 on the second portion of the first leg 510 and the connector 564 on the second portion of the second leg 520 are arranged similarly).

[0064] Ink source 190( Fig.14 ) and the piezoelectric inkjet printing device 8 or 9 or 10 or 11 are provided by an ink tube (not shown) which is connected to the ink interface 630 and directs the ink to the manifold 610. The ink inlet 235 ( Fig.14 ) is formed by a manifold 610 and a first plate 660, a second plate 670 and a third plate 680, as described in detail below. The first plate 660, the second plate 670 and the third plate 680 can be made of stainless steel. The manifold 610 and the outer third plate 680 provide mechanical protection for the piezoelectric inkjet printing device 8 or 9 or 10 or 11. The third plate 680 helps protect the nozzle orifice 132 during the wiping process and provides a capping surface for various printhead maintenance operations of the inkjet printing system 1. The mounting hole 611, for example, can be used to connect the inkjet printhead 5 to the transmission mechanism 16 ( Fig.14 ) on the pulley in ).

[0065] Fig.15 The side view of the piezoelectric inkjet print head 5 is shown, showing the inkjet face 601 including the nozzle orifice 132. Fig.16 5, showing a side view of a piezoelectric inkjet print head 5, showing a connection surface 602, including a slot 615 in a manifold 610, the slot extending along the row direction 51. The first leg 510 and the second leg 520 of the U-shaped flexible wiring board 500 extend through the slot 615 and are connected to the contact layer of the piezoelectric inkjet printing device 8 or 9 or 10 or 11 through the interconnection board 590 (as described above with reference to Fig.10 and 11 The ink interface 630 is also connected to the connection surface 602 of the manifold 610 .

[0066] Fig.17The cross section of the piezoelectric inkjet print head 5 is shown, which cross section passes through the middle plane between the first part 511 and the second part 512 of the U-shaped flexible wiring board 500 (see FIG. Fig.15 As described above, the first leg 510 and the second leg 520 of the U-shaped flexible wiring board 500 extend through the slot 615, whereby the device connection area 505 is connected to the interconnection board 590 ( Fig.10 ) is electrically connected to the contact layer of the piezoelectric inkjet printing device 10. Fig.17 In the example shown, the contact layer for electrical connection with the device connection area 505 is located on the outer surface of the piezoelectric plate, so the piezoelectric inkjet printing device in this example can also be a piezoelectric inkjet printing device 9. The connection of the print head 5 with the piezoelectric inkjet printing device 8 or 11 will be as follows Fig.11 1 ). A strip plate 580 is disposed along the row direction 51, adjacent to the device connection region 505 between the first leg 510 and the second leg 520 of the U-shaped flexible wiring board 500. The strip plate 580 provides structural support and stress relief for the connection between the U-shaped flexible wiring board 500 and the piezoelectric inkjet printing device 10. It also helps keep the legs 510 and 520 separated from each other. Fig.17 The cross-sectional view of FIG. 6 also shows a portion of a fluid channel, which is formed by the slot 640 on the manifold 610, the first plate 660, the second plate 670 and the third plate 680, to provide ink to the ink inlet 235. The first plate 660 is bonded to the fluid connection surface 650 of the manifold 610, and the piezoelectric inkjet printing device 10 is bonded to the first plate 660 so that the first plate 660 is disposed between the fluid connection surface 650 and the piezoelectric inkjet printing device 10. The second plate 670 has a first surface 674 ( Fig. 22 ) is bonded to one side 663 of the first plate 660 ( Fig. 20 ), which face 663 is opposite to the face of the first plate bonded to the fluid connection face 650 of the manifold 610. The third plate 680 is bonded to the second face 673 ( Fig. 22 ), the second surface 673 is opposite to the first surface 674 of the second plate 670. The second plate 670 has a thickness substantially the same as that of the piezoelectric inkjet printing device 10 (i.e., within 20 microns), so that on the inkjet surface 601 of the piezoelectric inkjet printing head 5, the second surface 673 of the second plate 670 is aligned with the nozzle layer 330 ( Fig.14 The outer surface of the orifice layer 330 is slightly lower than the outer surface 681 of the thin third plate 680, so that the orifices are protected.

[0067] Fig.18 Shown is an exploded side view of the piezoelectric inkjet printing device 10, the interconnect board 590, and the U-shaped flexible wiring board 500. The connector 564 mounted on the inside of the second portion 522 of the second leg 520 is visible at this angle.

[0068] Fig.19 A side view of manifold 610 is shown, showing fluid connection surface 650. Slot 640 includes two ends 645, where ink passes through ink interface 630 ( Fig.15 ) enters the two ends 645. The first section 641 is located on one side of the slot 615, extending between the two ends 645 along the row direction 51, and is the ink inlet 235 ( Fig.14 ) to provide ink, thereby providing ink to the drop ejector row 181. The second segment 642 is located on the other side of the slot 615 and extends between the two ends 645 along the row direction 51 to provide ink for the ink inlet 235 ( Fig.14 ) to provide ink to the drop ejector row 182. In other words, the slot 640 is displaced relative to the slot 615. With two ink ports 630 and one slot 640 connected to the two ink ports, the two ink ports 630 can be used to input ink. Alternatively, one can be used as an input and one as an output to circulate ink through the manifold 610 for cleaning, removing bubbles or particles, ink mixing or refreshing, or for thermal control.

[0069] Fig. 20 Shows something like Fig.19 From a side view, the first plate 660 is bonded to the fluid connection surface 650 ( Fig.19 ). The first plate 660 includes a surface bonded to the fluid connection surface of the manifold 610 and the surface 650, and also includes a surface 663 opposite to the surface. The ends of the first plate 660 cover the two ends 645 ( Fig.19 ). The openings 661 and 662 in the first plate 660 expose the first section 641 and the second section 642 of the slot 640, respectively. The opening 665 of the first plate 660 exposes the slot 615 in the manifold 610.

[0070] Fig.21 Shows the Fig. 20 Similarly, from a side view, the piezoelectric inkjet printing device 10 is bonded to the face 663 of the first plate 660. The piezoelectric inkjet printing device 10 spans across the slot 615 of the manifold 610. The piezoelectric inkjet printing device 10 is suspended above the openings 661 and 662 of the first plate 660, allowing ink to flow into the ink inlet 235 ( Fig.14 ).

[0071] Fig. 22 Shows the Fig.21 Similarly, from a side view, the first surface 674 of the second plate 670 is bonded to the surface 663 of the first plate 660 ( Fig.21 The opening 671 of the second plate 670 passes over the piezoelectric inkjet printing device 10 and the openings 661 and 662 in the first plate 660 ( Fig. 20The nozzle hole 132 does not extend all the way to the end portion 20 of the piezoelectric inkjet printing device 10.

[0072] Fig.23 Shows the Fig. 22 Similarly, from a side view, the third plate 680 is bonded to the second surface 673 of the second plate 670. The third plate 680 has an opening 700 above the outer surface of the nozzle of the piezoelectric inkjet printing device to expose the nozzle area. The third plate 680 covers the opening 671 of the second plate 670, but is shown as transparent so that the opening 671 can be seen in the figure. The third plate 680 covers the two end portions 20 and the two side portions 21 ( Fig. 22 ). The purpose of the third plate 680 is to seal the fluid passage from the slot 640 to the first plate 660 and the second plate 670. The third plate 680 also overlaps the edge of the piezoelectric inkjet printing device 10 to protect the nozzle orifice 132 from damage.

[0073] Fig.24 A side view of the manifold 610 and the U-shaped flexible wiring board 500 is shown, with the piezoelectric inkjet printing device 10 and the three boards 660, 670 and 680 hidden, so that a pair of legs 510 and 520 of the U-shaped flexible wiring board 500 and the device connection area 505 in the slot 615 of the manifold 610 are clearly visible.

[0074] For simplicity, Figure 15-23 The connection between a piezoelectric inkjet print head 5 and a piezoelectric inkjet printing device 9 or 10 is shown. The connection between the piezoelectric inkjet print head 5 and the piezoelectric inkjet printing device 8 or 11 is similar, as shown in FIG. Fig.11 As shown, the device connection area 505 of the U-shaped flexible wiring board 500 extends into the opening 218 of the piezoelectric plate 210. The outer appearance of the piezoelectric inkjet print head 5 with the piezoelectric inkjet printing device 9 or 10 is similar enough to the piezoelectric inkjet print head 5 with the piezoelectric inkjet printing device 8 or 11, so any of these four types can be installed in the same inkjet printing system 1 ( Fig.14 Since the piezoelectric inkjet printing device 8 or 9 or 11 may be more energy efficient than the piezoelectric inkjet printing device 10, it may be necessary to adjust the printing parameters (e.g., Fig.14 The electric pulse waveform in the electric pulse source 15).

[0075] Fig.25 3 is a schematic diagram of a logic circuit board 30 connected to a U-shaped flexible wiring board 500 of a piezoelectric inkjet print head 5. The logic circuit board 30 is located between a first leg 510 and a second leg 520 of the U-shaped flexible wiring board 500 ( Figure 15-18), so that the circuit board connectors 31-34 are connected to the connectors 561-564 respectively. The circuit board connectors 31 and 32 are mounted on the upper side (towards the viewer) of the logic circuit board 30, and the circuit board connectors 33 and 34 are mounted on the lower side of the logic circuit board 30. Fig.25 In the example shown, the cable 40 is connected to the logic circuit board 30 at the cable connector 41, and the number of conductors is approximately 20 (not shown). The printing device connector 45 provides a connection between the cable 40 and the inkjet printing system 1 ( Fig.14 ) other parts, such as the controller 14 and the electrical pulse source 15. The cable 40 includes inputs to the logic device 35, such as logic voltage, ground, clock, data, electrical pulses and other functions. These inputs are connected to the logic device 35 through the control line 38. The ground line 37 also provides grounding for the connectors 31-34. The logic device 35 provides firing pulses to the connectors 31-34 through the signal line 36 for controlling the droplet ejector 150 of the piezoelectric inkjet printing device 8 or 9 or 10 or 11. As described above with reference to Fig.13 As described, the piezoelectric inkjet printing device 8 or 9 or 10 or 11 can have 360 ​​signal inputs plus several ground inputs. The logic circuit board 30 facilitates electrical connections, and only approximately 20 wires are required to connect the piezoelectric inkjet print head 5 to the rest of the inkjet printing system 1. This is particularly important for an inkjet printing system 1, such as a sled printer, because the cable 40 will not be awkward or too stiff when the piezoelectric inkjet print head 5 moves back and forth. The logic circuit board 30 is typically a rigid printed circuit board. Alternatively, the logic circuit board 30 and the cable 40 can be part of a single flexible wiring board. In this case, the cable connector 41 is not required. The logic circuit board 30 may also include passive components, such as capacitors and resistors (not shown), or other active components (not shown).

[0076] The invention has been described in detail herein with particular reference to certain preferred embodiments thereof, but it will be understood that variations and modifications are encompassed within the spirit and scope of the invention.

Claims

1. A piezoelectric inkjet print head, characterized in that: include: A piezoelectric inkjet printing device, comprising: a substrate; At least one row of droplet ejectors is disposed on the substrate, each row being aligned along a row direction, each droplet ejector comprising: a pressure chamber; and A spray hole is disposed in the spray hole layer, wherein the spray hole is fluidically connected to the pressure chamber; A piezoelectric plate, comprising: A first surface is disposed adjacent to the pressure chamber, wherein the pressure chamber and the orifice layer are on opposite sides; and an outer second surface opposite the first surface; at least one ink inlet port provides ink to a pressure chamber of the drop ejector; a signal line corresponding to each drop ejector in at least one row, each signal line leading to a corresponding signal input pad; and At least one common ground line is arranged along the row direction, the common ground line is connected to the ground lines arranged between adjacent pressure chambers, wherein at least one common ground line leads to at least one ground return pad; a manifold fluidly connected to the at least one ink inlet; A U-shaped flexible terminal block, including: A device connection area, including: a plurality of signal connection pads, each signal connection pad facing a corresponding signal input pad; and At least one ground connection pad, each ground connection pad facing a corresponding ground return pad; A pair of legs extending outwardly from the device connection area, each of the pair of legs comprising: a plurality of signal connection lines, each signal connection line extending outwardly from a corresponding signal connection pad; and at least one ground connection line, each ground connection line extending outwardly from a corresponding ground connection pad; and An interconnection board is arranged between the device connection area of ​​the U-shaped flexible wiring board and the contact layer of the piezoelectric inkjet printing device, and the contact layer includes a signal input pad and at least one return pad.

2. The piezoelectric inkjet print head according to claim 1, characterized in that: The contact layer is located on the first surface of the substrate.

3. The piezoelectric inkjet print head according to claim 2, characterized in that: The device connection area of ​​the U-shaped flexible wiring board extends through the opening in the piezoelectric board to connect to the signal input pad and at least one ground return pad on the first side of the substrate.

4. The piezoelectric inkjet print head according to claim 1, characterized in that: The contact layer is located on the outer second surface of the piezoelectric plate.

5. The piezoelectric inkjet print head according to claim 1, characterized in that: The invention further comprises a strip plate arranged along the row direction, the strip plate being adjacent to the device connection area between the two legs of the U-shaped flexible wiring board.

6. The piezoelectric inkjet print head according to claim 1, characterized in that: A plurality of signal connection lines and at least one ground connection line on each leg are electrically connected to at least one connector mounted on the U-shaped flexible wiring board.

7. The piezoelectric inkjet print head according to claim 6, characterized in that: A first connector mounted on a first leg of the pair of legs and a second connector mounted on a second leg of the pair of legs face each other and are offset from each other.

8. The piezoelectric inkjet print head according to claim 1, characterized in that: Each leg in a pair is bifurcated.

9. The piezoelectric inkjet print head according to claim 1, characterized in that: The manifold includes a slot arranged in a row direction, wherein the piezoelectric inkjet printing device extends across the slot, and wherein two legs of the U-shaped flexible wiring board extend through the slot.

10. The piezoelectric inkjet print head according to claim 9, characterized in that: The manifold includes a fluid connection surface having a groove, wherein the groove is offset from the slot, and the piezoelectric inkjet print head further includes: The first plate is disposed between the fluid connection surface and the piezoelectric inkjet printing device; A second plate having a first side bonded to a side of the first plate opposite the manifold fluid connection side; and The third plate is bonded to a second side of the second plate opposite the first side.

11. The piezoelectric inkjet print head according to claim 10, characterized in that: The first plate, the second plate, and the third plate define a fluid passage between a groove in the fluid connection surface and at least one ink inlet.

12. The piezoelectric inkjet print head according to claim 10, characterized in that: Each of the first plate, the second plate, and the third plate includes a stainless steel material.

13. The piezoelectric inkjet print head according to claim 10, characterized in that: The second plate has substantially the same thickness as the piezoelectric inkjet printing device.

14. The piezoelectric inkjet print head according to claim 1, characterized in that: The manifold is fluidly connected to the ink inlets of at least two piezoelectric inkjet printing devices.

15. The piezoelectric inkjet print head according to claim 14, characterized in that: The manifold is fluidly connected to at least two ink interfaces.

16. The piezoelectric inkjet print head according to claim 1, characterized in that: The interconnection board includes an anisotropic conductive film.

17. The piezoelectric inkjet print head according to claim 1, characterized in that: The substrate comprises a first edge and a second edge, each edge extending along a row direction, wherein at least one ink inlet is disposed in at least one of the first edge and the second edge.

18. A piezoelectric inkjet printing system, characterized in that: include: A piezoelectric inkjet print head, comprising: A piezoelectric inkjet printing device, comprising: a substrate; At least one row of droplet ejectors is disposed on the substrate, each row being aligned along a row direction, each droplet ejector comprising: a pressure chamber; and A spray hole is disposed in the spray hole layer, wherein the spray hole is fluidically connected to the pressure chamber; A piezoelectric plate, comprising: A first surface is disposed adjacent to the pressure chamber, wherein the pressure chamber and the orifice layer are on opposite sides; and an outer second surface opposite the first surface; at least one ink inlet port provides ink to a pressure chamber of the drop ejector; a signal line corresponding to each drop ejector in at least one row, each signal line leading to a corresponding signal input pad; and At least one common ground line, wherein the common ground line is connected to a ground line disposed between adjacent pressure chambers, wherein the at least one common ground line leads to at least one ground return pad; a manifold fluidly connected to the at least one ink inlet; A U-shaped flexible terminal block, including: A device connection area, including: a plurality of signal connection pads, each signal connection pad facing a corresponding signal input pad; and At least one ground connection pad, each ground connection pad facing a corresponding ground return pad; A pair of legs extending outwardly from the device connection area, each of the pair of legs comprising: a plurality of signal connection lines, each signal connection line extending outwardly from a corresponding signal connection pad; and at least one ground connection line, each ground connection line extending outwardly from a corresponding ground connection pad; and An interconnection board is arranged between the device connection area of ​​the U-shaped flexible wiring board and the contact layer of the piezoelectric inkjet printing device, and the contact layer includes a signal input pad and at least one return pad; An image data source; A controller; a source of electrical pulses; and A logic board is connected to the U-shaped flexible terminal block.

19. The piezoelectric inkjet printing system according to claim 18, characterized in that: The logic board is connected to the controller and the source of electrical pulses.

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