JP2010201673A - Liquid jetting head and liquid jetting apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid jetting head which can surely secure a predetermined potential difference from other members of the opposite potential by stably maintaining a liquid droplet at one potential. <P>SOLUTION: The liquid jetting head is equipped with nozzle openings 21 which are formed in a nozzle plate 20 to eject liquid droplets, a plurality of pressure generating chambers 12 which communicate with the nozzle openings and are sectioned by partition walls, a reservoir 100 which communicates with each pressure generating chamber and stores the liquid to be supplied to each pressure generating chamber, piezoelectric elements 300 which generates a pressure for ejection of the liquid droplets generated in each pressure generating chamber, and a compliance substrate 40 which includes an ink introductory opening 44 for introducing the liquid to the common liquid chamber and seals the reservoir. The nozzle plate is formed of a material having smaller electrical conductivity than that of the compliance part, and at least a part of the compliance part in contact with the liquid via the liquid introductory opening is formed by a conductive member. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a liquid ejecting head and a liquid ejecting apparatus, and is particularly useful when applied to the case of detecting missing dots by charging ink ejected from nozzles.

  As an ink jet recording head which is a liquid ejecting head, a part of a pressure generating chamber communicating with a nozzle opening for ejecting ink droplets is constituted by a vibration plate, and the vibration plate is deformed by a piezoelectric element so that ink in the pressure generating chamber is formed. There is known a piezoelectric element having a flexural vibration mode in which an ink droplet is ejected from a nozzle opening. Here, a flow path forming substrate in which a plurality of pressure generating chambers that are communicated with the nozzle openings formed in the nozzle plate and partitioned by a partition wall are arranged in parallel, and a region facing the pressure generating chambers of the flow path forming substrate. A piezoelectric element in which a lower electrode film, a piezoelectric layer, and an upper electrode film are laminated through an insulating film serving as a vibration plate, and a part of a reservoir that is bonded to a flow path forming substrate and serves as a common ink chamber for a pressure generating chamber As a typical example, a substrate provided with a reservoir forming substrate provided with a reservoir portion that constitutes (see, for example, Patent Document 1) can be given.

  Incidentally, in an ink jet recording apparatus having this type of ink jet recording head, dot missing detection is performed at a predetermined timing such as before printing in order to ensure a predetermined print quality. Various methods for detecting missing dots have been proposed, and one of them is to charge the ink by applying a voltage between the flushing box and the nozzle plate, and to discharge the charged ink to discharge the flushing box. There has been proposed a method of detecting a missing dot based on the amplitude of the potential signal by outputting a potential signal representing a change in potential between the nozzle plate and the nozzle plate (see, for example, Patent Document 2). This utilizes the fact that the amplitude of the potential signal differs between when the charged ink is ejected normally and when it is not. By the way, in a specific nozzle row consisting of a plurality of nozzles, the larger the number of nozzles that cannot eject ink normally, the smaller the amplitude of the potential signal that is output, so the amplitude of the potential signal must be detected. Thus, it is possible to grasp the number of nozzles causing dot missing.

JP 2007-26125 A (Fig. 2 etc.) Japanese Patent Laid-Open No. 7-68752 (FIG. 1 etc.)

  The missing dot detection based on the potential signal as described above is usually realized by connecting the nozzle plate to the ground and applying a voltage with the flushing box on the plus side. That is, it is assumed that the nozzle plate is formed of a conductive material such as SUS so that ink discharged through the nozzle opening can be charged to the negative side.

  On the other hand, in order to apply dry etching technology to form the nozzle opening at a predetermined position of the nozzle plate with high accuracy, the nozzle plate is formed of silicon as a semiconductor, and an insulating film is formed on the surface of the silicon nozzle plate, Some have nozzle openings.

  Therefore, the dot missing detection method as described above cannot be applied to an ink jet recording head having a silicon nozzle plate. This is because the nozzle plate cannot be stably maintained at the ground potential.

  Such a problem exists not only in an ink jet recording head that ejects ink droplets but also in a liquid ejecting head that ejects other droplets.

  SUMMARY An advantage of some aspects of the invention is that it provides a liquid ejecting head and a liquid ejecting apparatus that can stably maintain a droplet at one potential.

One embodiment of the present invention that achieves the above object is a nozzle plate in which nozzle openings for discharging droplets are formed, a plurality of pressure generation chambers communicating with the nozzle openings, and a common supply of liquid to the pressure generation chambers A wall surface of the common liquid chamber is formed by including a liquid chamber, a pressure generating means for generating a pressure for discharging droplets in the pressure generating chamber, and a liquid inlet for introducing the liquid into the common liquid chamber. A liquid ejecting head having a common liquid wall portion, wherein the nozzle plate has an electric conductivity smaller than that of the common liquid wall portion, and a common liquid wall portion in contact with the liquid via the liquid introduction port. At least a part of the liquid ejecting head has conductivity.
According to this aspect, since the droplet can be brought into contact with the compliance portion having higher electrical conductivity than the nozzle plate, it is easy to stably maintain the droplet at one potential via the compliance portion. It becomes possible.

  Here, the nozzle plate is preferably formed of silicon. In this case, since the thermal expansion coefficient is the same as that of the other members, no adverse effects due to heating are caused even if the wiring is connected by applying heat to the piezoelectric element or the like. Moreover, it is desirable that at least a part of the compliance portion is formed of stainless steel. In this case, the conductive portion can be easily secured. Further, it is desirable that the compliance portion is covered with a head case that contacts the surface thereof, and a notch portion is provided in a part of the head case to expose a portion having the same potential as the liquid inlet of the compliance portion. . In this case, even when the conducting wire is connected to this portion, such as when the compliance portion is dropped to the ground, a desired connection can be made without forming a protruding portion on the liquid ejecting head.

According to another aspect of the present invention, the liquid jet head, power supply means for forming a predetermined potential difference between the liquid inlet of the compliance section and a portion having the same potential as the liquid inlet, and the other conductive member, and the compliance And a potential detecting unit that determines a discharge state of the droplet from the nozzle opening based on a potential signal that represents a change in potential between the first conductive member and the other conductive member.
According to this aspect, since the liquid in the common liquid chamber can be stably charged to one potential via the compliance portion, even if the nozzle plate is an insulator, the compliance portion and the other conductive member By detecting a change in potential between them, it is possible to detect dot missing easily and reliably.

FIG. 3 is an exploded perspective view of the ink jet recording head unit according to the embodiment. FIG. 2 is an assembled perspective view of the head unit of FIG. 1. FIG. 2 is a cross-sectional view of a main part of the head unit in FIG. 1. FIG. 2 is an exploded perspective view of a main part of the head unit in FIG. 1. Sectional drawing which extracts and shows a part of FIG. 3 (however, a notch part and its vicinity part are remove | excluded). 1 is a schematic diagram of an ink jet recording apparatus according to an embodiment. Explanatory drawing which shows the aspect at the time of dot missing detection. The wave form diagram of the potential signal which is an output signal at the time of dot missing detection.

Embodiments of the present invention will be described below in detail with reference to the drawings.
FIG. 1 is an exploded perspective view of an ink jet recording head unit according to the present embodiment, FIG. 2 is an assembled perspective view thereof, and FIG.

  As shown in these drawings, the ink jet recording head unit 200 (hereinafter referred to as the head unit 200) includes a cartridge case 210, a plurality of (four in this embodiment) heads 220, a cover head 240, and a fixing plate. An ink jet recording head 219 integrated with a cover portion 235 made of 250 is provided.

  Of these, the cartridge case 210 is a holding member for the ink cartridge having a cartridge mounting portion 211 to which an ink cartridge (not shown) is mounted. The ink cartridge is an ink supply unit configured as a separate body filled with, for example, black and three color inks. That is, each color ink cartridge is mounted in the cartridge case 210.

  Further, as clearly shown in FIG. 3, the cartridge case 210 is provided with a plurality of ink communication paths 212 having one end opened to each cartridge mounting portion 211 and the other end opened to the head case 230 side. Further, an ink supply needle 213 to be inserted into the ink supply port of the ink cartridge is fixed to the opening portion of the ink communication path 212 of the cartridge mounting portion 211. This fixing is performed through a filter (not shown) formed in the ink communication path 212 in order to remove bubbles and foreign matters in the ink.

  The head case 230 is fixed to the bottom surface of the cartridge case 210. The head 220 has a plurality of piezoelectric elements 300 and ejects ink droplets from the nozzle openings 21 by driving the piezoelectric elements 300 on the end surface opposite to the cartridge case 210, and ejects ink of each color of the ink cartridge. A plurality of ink colors are provided for each ink color. Therefore, a plurality of head cases 230 are also provided independently for each head 220.

  The head 220 and the head case 230 as described above will be described in further detail with reference to FIGS. 4 is an exploded perspective view of main parts of the head 220 and the head case 230, and FIG. 5 is a cross-sectional view of the head 220 and the head case 230.

  As shown in both figures, the head 220 is composed of four substrates: a nozzle plate 20, a flow path forming substrate 10, a protective substrate 30, and a compliance substrate 40. Among these, the flow path forming substrate 10 is made of a silicon single crystal substrate in this embodiment, and an elastic film 50 made of silicon dioxide previously formed by thermal oxidation is formed on one surface thereof. The flow path forming substrate 10 is formed with a pressure generating chamber 12 partitioned by a plurality of partition walls. In this embodiment, the two pressure generation chambers 12 in two rows in the width direction of the flow path forming substrate 10 are formed by anisotropic etching from the other surface side of the flow path forming substrate 10. Further, on the outer side in the longitudinal direction of the pressure generating chambers 12 in each row, a communicating portion constituting a reservoir 100 that communicates with a reservoir portion 31 provided on a protective substrate 30 to be described later and serves as a common ink chamber for each pressure generating chamber 12. 13 is formed. The communication portion 13 is in communication with one end portion in the longitudinal direction of each pressure generating chamber 12 through the ink supply path 14.

  A nozzle plate 20 is fixed to the opening surface side of the flow path forming substrate 10 via an adhesive, a heat welding film, or the like. The nozzle plate 20 is formed with nozzle openings 21 communicating with the pressure generation chambers 12 on the side opposite to the ink supply path 14. Thus, in this embodiment, two rows of nozzle rows 21A in which the nozzle openings 21 are arranged in one head 220 are provided.

  The nozzle plate 20 in this embodiment is formed of a silicon single crystal substrate. An insulating (low electrical conductivity) liquid repellent film is formed on the surface of the nozzle plate 20 opposite to the flow path forming substrate 10.

  On the other hand, the piezoelectric element 300 is disposed on the elastic film 50 on the side opposite to the opening surface of the flow path forming substrate 10. The piezoelectric element 300 is formed by sequentially laminating an insulator film 55 made of zirconium oxide, a lower electrode film made of metal, a piezoelectric layer made of lead zirconate titanate (PZT), and an upper electrode film made of metal. Is done.

  The protective substrate 30 is bonded onto the flow path forming substrate 10 on which the piezoelectric element 300 is formed. In this embodiment, the reservoir portion 31 is formed through the protective substrate 30 in the thickness direction and across the width direction of the pressure generating chamber 12, and communicates with the communication portion 13 of the flow path forming substrate 10 as described above. Thus, the reservoir 100 serving as an ink chamber common to the pressure generation chambers 12 is configured. A piezoelectric element holding portion 32 having a space that does not hinder the movement of the piezoelectric element 300 is provided in a region of the protective substrate 30 that faces the piezoelectric element 300. Such a protective substrate 30 can be suitably formed of glass, ceramic, metal, plastic, or the like, but it is preferable to use a material substantially the same as the coefficient of thermal expansion of the flow path forming substrate 10. It is formed using a silicon single crystal substrate made of the same material as the formation substrate 10.

  Furthermore, a drive IC 110 for driving each piezoelectric element 300 is provided on the protective substrate 30. Each terminal of the drive IC 110 is connected to a lead wire drawn from the individual electrode of each piezoelectric element 300 via a bonding wire or the like (not shown). Each terminal of the driving IC 110 is connected to the outside via an external wiring 111 such as a flexible printed cable (FPC) as shown in FIG. 1, and various signals such as a print signal from the outside via the external wiring 111. To receive.

  The compliance substrate 40 is bonded onto the protective substrate 30, and an ink introduction port 44 for supplying ink to the reservoir 100 is formed through the thickness direction in a region facing the reservoir 100. Further, a region other than the ink introduction port 44 in the region facing the reservoir 100 of the compliance substrate 40 is a sealing film 41 that is a flexible portion formed thin in the thickness direction. The film 41 is sealed. That is, the compliance substrate 40 is formed of the sealing film 41 and the fixing plate 42 as clearly shown in FIG. Here, the sealing film 41 is formed of a material having low rigidity and flexibility (for example, a polyphenylene sulfide (PPS) film having a thickness of 6 μm), and the fixing plate 42 is made of a hard material such as metal. It is made of a material (for example, stainless steel (SUS) having a thickness of 30 μm). Since the region of the fixing plate 42 facing the reservoir 100 is an opening 43 that is completely removed in the thickness direction, one surface of the reservoir 100 is sealed only with a flexible sealing film 41. In addition, the sealing film 41 is configured to give compliance to the reservoir 100.

  Therefore, the ink flowing into the reservoir 100 via the ink introduction port 44 contacts the fixing plate 42 at the ink introduction port 44 portion. Here, the fixing plate 42 is a conductor that forms a part of the compliance substrate 40. As a result, the ink flowing into the reservoir 100 and the compliance substrate 40 are electrically at the same potential.

  A notch 234 is provided at one corner of the head case 230, and the surface of the fixing plate 42 of the compliance substrate 40 corresponding to this notch 234 is exposed by this notch 234. Such an exposed portion has the same potential as the ink inlet 44. As a result, the ink in the reservoir 100 can be easily maintained at, for example, the ground potential using the exposed portion of the fixed plate 42.

  The head case 230 is provided with a drive IC holding portion 233 that penetrates in the thickness direction in a region facing the drive IC 110 provided on the protective substrate 30, and the external wiring 111 connects the drive IC holding portion 233. It is inserted and connected to the drive IC 110.

  As shown in FIGS. 1 to 3, four heads 220 and head cases 230 are fixed to the cartridge case 210 at predetermined intervals in the arrangement direction of the nozzle rows 21A. That is, the head unit 200 is provided with eight nozzle rows 21A.

  In this way, by increasing the number of nozzle rows 21A including the nozzle openings 21 arranged in parallel by using a plurality of heads 220, the yield can be increased as compared with the case where the nozzle rows 21A are formed in multiple rows in one head 220. A decrease can be prevented. Further, by using a plurality of heads 220 to increase the number of nozzle rows 21A, the number of heads 220 that can be formed from a single silicon wafer can be increased, and the wasteful area of the silicon wafer can be reduced. Manufacturing cost can be reduced.

  Further, as shown in FIGS. 1 and 3, the four heads 220 are positioned by a fixing plate 250 of a cover portion 235 that is a common fixing member joined to the ink droplet ejection surfaces of the plurality of heads 220. Is held. The fixed plate 250 is a flat plate, defines an exposed opening 251 that exposes the nozzle opening 21, an exposed opening 251, and is joined to at least both ends of the nozzle row 21 </ b> A on the ink droplet discharge surface of the head 220. A joining portion 252. The joining portion 252 extends between the fixing frame portion 253 provided along the outer periphery of the ink droplet ejection surface across the plurality of heads 220 and the adjacent head 220 to fix the exposure opening 251. The joint portion 252 including the fixing beam portion 254 and including the fixing frame portion 253 and the fixing beam portion 254 is simultaneously bonded to the ink droplet ejection surface side of the plurality of heads 220.

  In this embodiment, the thickness of the fixed plate 250 is 0.1 mm. The joining of the fixing plate 250 and the nozzle plate 20 is not particularly limited, and can be suitably performed using, for example, a thermosetting epoxy adhesive, an ultraviolet curable adhesive, or the like.

  As described above, since the fixing plate 250 blocks the adjacent heads 220 by the fixing beam portion 254, the ink does not enter between the adjacent heads 220, and the piezoelectric element 300, the driving IC 110, etc. Deterioration and destruction of the head 220 due to ink can be prevented. Further, since the ink droplet discharge surface of the head 220 and the fixing plate 250 are bonded without any gap by an adhesive, the recording medium is prevented from entering the gap, and deformation of the fixing plate 250 and paper jamming are prevented. Can be prevented.

  Further, as shown in FIGS. 1 and 2, the head unit 200 is provided with a cover head 240 having a box shape so as to cover each head 220 on the side opposite to the head 220 with respect to the fixed plate 250. Yes. The cover head 240 forms the cover portion 235 in the present embodiment together with the fixed plate 250, the fixed portion 242 provided with the opening 241 corresponding to the exposed opening 251 of the fixed plate 250, and the ink droplets of the head 220. A side wall portion 245 provided to be bent over the outer periphery of the fixed plate 250 is provided on the side surface side of the discharge surface.

  The fixing portion 242 includes a frame portion 243 provided corresponding to the fixing frame portion 253 of the fixing plate 250 and a beam portion provided corresponding to the fixing beam portion 254 of the fixing plate 250 to divide the opening 241. 244. In addition, the fixing part 242 including the frame part 243 and the beam part 244 is joined to the joining part 252 of the fixing plate 250. Here, the cover head 240 is formed of a metal material such as stainless steel, for example, and a metal plate formed of the metal material may be formed by pressing or may be formed by molding.

  Further, as described above, since the ink droplet ejection surface of the head 220 and the cover head 240 are joined without a gap, the recording medium is prevented from entering the gap to prevent the cover head 240 from being deformed and paper jammed. can do. Further, since the side wall portion 245 of the cover head 240 covers the outer peripheral edge portions of the plurality of heads 220, it is possible to reliably prevent the ink from flowing into the side surfaces of the heads 220.

  In addition, as shown in FIGS. 2 and 3, the cover head 240 in this embodiment is fixed to a cartridge case 210 that is a holding member that holds the head 220 and the head case 230. More specifically, the cartridge case 210 is provided with a protrusion 215 that protrudes toward the ink droplet ejection surface and is inserted into the fixing hole 247 of the cover head 240. The protrusion 215 is fixed to the cover head 240. The cover head 240 is fixed to the cartridge case 210 by inserting into the hole 247 and heating and crimping the tip of the protrusion 215. The protrusion 215 provided on the cartridge case 210 has an outer diameter smaller than that of the fixing hole 247 of the flange 246, so that the cover head 240 is positioned in the surface direction of the ink droplet discharge surface and the cartridge case. 210 can be fixed.

  The cover head 240 and the fixing plate 250 to which the plurality of heads 220 are joined are fixed by positioning the fixing holes 247 of the cover head 240 and the plurality of nozzle rows 21A.

  According to this embodiment, the head 220 takes in ink from the ink cartridge from the ink introduction port 44 via the ink communication path 212 (see FIG. 3) and the ink supply communication path 231, and reaches from the reservoir 100 to the nozzle opening 21. Fill the inside with ink. In this state, a voltage is applied to each piezoelectric element 300 corresponding to the pressure generation chamber 12 in accordance with a recording signal from the drive IC 110 to cause the elastic film 50 and the piezoelectric element 300 to bend and deform, whereby each pressure generation chamber 12 Ink droplets are ejected from the nozzle openings 21.

  Here, since the ink in the reservoir 100 is in contact with the fixing plate 42 of the compliance substrate 40 which is a conductive portion through the ink introduction port 44, the ink is stably grounded by dropping the fixing plate 42 to the ground. It can be a potential. As a result, a predetermined voltage can be applied between the fixed plate 42 and another conductive member such as a flushing box, and dot missing detection performed by ejecting ink from the nozzle openings 21 can be favorably performed.

(Other embodiments)
As mentioned above, although embodiment of this invention was described, of course, this invention is not limited to what was mentioned above. For example, in the above embodiment, the nozzle plate 20 is formed of silicon. However, since the electrical conductivity of the compliance portion only needs to be higher than that of the nozzle plate, for example, when the compliance portion is formed of a highly conductive metal material, the nozzle In some cases, the plate may be formed of SUS. However, when the nozzle plate 20 is formed of silicon, the coefficient of thermal expansion is the same as that of other substrates such as the flow path forming substrate 10, so that even if the actuator is heated and the COF or the like is connected, an adverse effect due to heating will occur. Never do.

  Further, the configuration of the ink jet recording head is not limited to that described above. In the case where the nozzle plate is formed of an insulator or the like, the ink jet recording head system is not particularly limited as long as the ink in the reservoir is electrically connected via the compliance portion. For example, in the above-described embodiment, ink is ejected using flexural vibration, but it may be one using longitudinal vibration, one using electrostatic force, one using a heating element, or the like. .

  Furthermore, the ink jet recording head of this embodiment constitutes a part of a recording head unit having an ink flow path communicating with an ink cartridge or the like, and is mounted on the ink jet recording apparatus. FIG. 6 is a schematic view showing an example of the ink jet recording apparatus. As shown in the figure, the recording head units 1A and 1B in the ink jet recording apparatus are detachably provided with cartridges 2A and 2B constituting ink supply means, and a carriage 3 on which the recording head units 1A and 1B are mounted is provided. A carriage shaft 5 attached to the apparatus main body 4 is provided so as to be movable in the axial direction. The recording head units 1A and 1B, for example, are configured to eject a black ink composition and a color ink composition, respectively.

  The driving force of the driving motor 6 is transmitted to the carriage 3 via a plurality of gears and timing belt 7 (not shown), so that the carriage 3 on which the recording head units 1A and 1B are mounted is moved along the carriage shaft 5. The On the other hand, the apparatus body 4 is provided with a platen 8 along the carriage shaft 5, and a recording sheet S that is a recording medium such as paper fed by a paper feed roller (not shown) is wound around the platen 8. It is designed to be transported.

  Further, in the case of the ink jet recording apparatus shown in FIG. 6, an apparatus for detecting missing dots is also mounted. FIG. 7 is an explanatory diagram showing a mode when dot missing is detected. As shown in the figure, when detecting missing dots, the fixing plate 42 of the compliance substrate 40 of the head unit 200 is dropped to the ground, and the positive side of the DC power supply 410 is connected to the flushing box 400 which is a conductor. As a result, a predetermined potential difference is generated between the flushing box 400 and the fixing plate 42 of the compliance substrate 40. As a result, the flushing box 400 is positively charged, and the ink in the reservoir 100 (see FIG. 5) electrically connected to the fixing plate 42 of the compliance substrate 40 is negatively charged. When ink droplets are ejected in this state, the potential difference between the flushing box 400 and the fixed plate 42 of the compliance substrate 40 changes. The degree of the potential difference change is smaller as the number of nozzles causing dot missing is larger. In other words, in a specific nozzle array composed of a plurality of nozzles, the larger the number of nozzles that cannot eject ink normally, the smaller the amplitude of the potential signal that is output, so the amplitude of the potential signal is detected. Thus, it is possible to grasp the number of nozzles causing dot missing. The potential detection unit 420 detects and analyzes the potential signal representing the potential difference obtained at this time to detect the degree of missing dots, and controls the degree of suction in the flushing box 400 with the output signal OUT. That is, when there are many missing dots, cleaning is performed with a large suction force.

  FIG. 8 is a waveform diagram showing an example of a potential signal supplied to the potential detector 420 at this time. This figure shows potential signals obtained when ink is ejected from different nozzle rows at the timings of # 1, # 2, and # 3, and the nozzle rows ejected at # 1 cause missing dots. It shows that.

  Such dot omission detection is performed before printing for each printing. Specifically, first, the head unit 200 is moved to the home position of the non-printing area. As a result, the head unit 200 faces the flushing box, so that ink is ejected at this position. When dot missing is detected by the potential signal obtained as a result, predetermined suction is performed and dot missing is detected again. As a result, when dot missing is removed, predetermined printing is performed.

  In the above-described embodiment, the ink jet recording head has been described as an example of the liquid ejecting head of the present invention, but the basic configuration of the liquid ejecting head is not limited to the above. The present invention covers a wide range of liquid ejecting heads, and can naturally be applied to those ejecting liquids other than ink. Examples of the liquid ejecting head include various recording heads used in image recording apparatuses such as printers, color material ejecting heads used for manufacturing color filters such as liquid crystal displays, organic EL displays, and FED (field emission displays). Examples thereof include an electrode material ejection head used for electrode formation and a bioorganic matter ejection head used for biochip production.

  DESCRIPTION OF SYMBOLS 10 Flow path formation board | substrate, 12 Pressure generation chamber, 20 Nozzle plate, 21 Nozzle opening, 40 Compliance board | substrate, 100 Reservoir, 200, Head unit, 219 Inkjet recording head, 220 head, 234 Notch part, 300 Piezoelectric element

Claims (5)

A nozzle plate having a nozzle opening for discharging droplets, a plurality of pressure generation chambers communicating with the nozzle openings, a common liquid chamber for supplying liquid to the pressure generation chamber, and droplet discharge into the pressure generation chamber A liquid ejecting head comprising: pressure generating means for generating pressure for the liquid; and a common liquid wall portion having a liquid inlet for introducing the liquid into the common liquid chamber and forming a wall surface of the common liquid chamber Because
The nozzle plate has electrical conductivity smaller than that of the common liquid wall, and at least a part of the common liquid wall that comes into contact with the liquid via the liquid inlet has conductivity. Liquid jet head. The liquid ejecting head according to claim 1,
The liquid ejecting head, wherein the nozzle plate is made of silicon. The liquid ejecting head according to claim 1,
The liquid ejecting head according to claim 1, wherein at least a part of the compliance portion is made of stainless steel. The liquid ejecting head according to any one of claims 1 to 3,
The compliance portion is covered with a head case that abuts on the surface thereof, and a portion having the same potential as the liquid inlet of the compliance portion is exposed by providing a cutout portion in a part of the head case. Liquid ejecting head.   A predetermined potential difference is formed between the liquid ejecting head according to any one of claims 1 to 4, a portion having the same potential as the liquid inlet of the compliance portion, and another conductive member. It has a power supply means and a potential detection means for judging a discharge state of a droplet from the nozzle opening based on a potential signal representing a change in potential between the compliance portion and the other conductive member. Liquid ejector.

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