JP2004114315A - Liquid drop ejecting head, ink cartridge, and inkjet recorder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem that the assembling process of a head is intricate because a damper mechanism for absorbing pressure is provided in a common liquid chamber and the head itself becomes bulky. <P>SOLUTION: A channel substrate 1 and a nozzle plate 4 comprising a resin member are bonded while being superposed to form an ejection chamber 6 communicating with a plurality of nozzles 5, and a common liquid chamber 8 communicating with the ejection chamber 6 through a flow resistance part 7. Wall face of the common liquid chamber 8 is formed of the nozzle plate 4 and the volume of the common liquid chamber is set not larger than twenty times that of each ejection chamber. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
[Industrial applications]
The present invention relates to a droplet discharge head and an ink jet recording apparatus.
[0002]
[Prior art]
[Patent Document 1] JP-A-2001-277524 [Patent Document 2] JP-A-2002-0119109
2. Description of the Related Art In general, an ink jet head, which is a droplet discharge head used in an image recording apparatus such as a printer, a facsimile, and a copying apparatus or an ink jet recording apparatus used as an image forming apparatus, supplies ink from outside to a common liquid chamber. To each of the discharge chambers (also referred to as a liquid chamber, a flow path, a pressurized liquid chamber, a pressurized chamber, and an individual liquid chamber), and energy is applied to the ink in the discharge chambers by energy generating means (pressure generating means). As a result, ink droplets are ejected from the nozzles.
[0004]
In such an ink jet head, energy given in the discharge chamber is transmitted to the common liquid chamber as a pressure wave, and the pressure wave affects the peripheral discharge chamber through the common liquid chamber, When the ink droplets are simultaneously ejected from the nozzles, the pressure waves from the ejection chambers may cause interference in the common liquid chamber, causing unstable ink droplet ejection or ejection failure.
[0005]
Therefore, in the conventional inkjet head,
As disclosed in Patent Literature 1 and Patent Literature 2, a damper mechanism is provided by providing a plate-like member having an elastically deformable portion that elastically deforms in a common liquid chamber, and a pressure wave in the common liquid chamber is reduced. I try to attenuate it.
[0006]
[Problems to be solved by the invention]
However, if a damper mechanism for absorbing pressure is provided in the common liquid chamber as in the above-described conventional ink jet head, there is a problem that the head assembling process becomes complicated and long, and the head itself becomes large.
[0007]
If the common liquid chamber is not provided with a damper function, there is a method of increasing the volume of the common liquid chamber to attenuate the pressure wave, but the head taken up by the volume taken by the common liquid chamber, In addition, when the volume of the common liquid chamber is increased, there is also a problem that it is difficult to discharge the entrained bubbles. Since it is difficult to discharge the bubbles, the recovery operation mechanism becomes large, and the amount of ink used for recovery also increases.
[0008]
SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has a simple configuration, has no defective discharge, and can easily discharge bubbles, a head-integrated ink cartridge, and these liquid discharge heads Another object is to provide an ink jet recording apparatus equipped with an ink cartridge.
[0009]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, in the droplet discharge head according to the present invention, the volume of the common liquid chamber is not more than 20 times the volume of each discharge chamber communicating with the common liquid chamber, and the wall surface of the common liquid chamber is Is configured to be a resin member.
[0010]
Here, at least the portion of the nozzle plate serving as the wall of the common liquid chamber has a Young's modulus of E [N / m ³ ] and a thickness of h [m], where 0.00001 [N] ≦ Eh ^3. It is preferable to satisfy ≦ 0.0006 [N]. The thickness of the nozzle plate is preferably 10 μm or more and 40 μm or less. Further, the Young's modulus of the nozzle plate is preferably 2E10 [N / m ³ ] or less.
[0011]
The ink cartridge according to the present invention integrates the droplet discharge head according to the present invention and an ink tank that supplies ink to the head.
[0012]
An inkjet recording apparatus according to the present invention includes the droplet discharge head or the ink cartridge according to the present invention.
[0013]
Embodiment
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. First, a first embodiment of an ink jet head as a droplet discharge head according to the present invention will be described with reference to FIGS. 1 is an exploded perspective view of the head, FIG. 2 is a plan view showing the nozzle plate of the head in a transparent state, FIG. 3 is a schematic cross-sectional view of the head taken along the longitudinal direction of the diaphragm, and FIG. FIG. 3 is a schematic cross-sectional explanatory view of the same head along the transverse direction of the diaphragm.
[0014]
The inkjet head includes a flow path substrate 1 as a first substrate, an electrode substrate 3 as a second substrate provided below the flow path substrate 1, and a third substrate provided above the flow path substrate 1. This is a laminated structure in which a certain nozzle plate 4 is overlapped and joined, thereby forming a discharge chamber 6 in which a plurality of nozzles 5 communicate with each other, a common liquid chamber 8 in communication with the discharge chamber 6 via a fluid resistance portion 7, and the like. are doing.
[0015]
The flow path substrate 1 includes a discharge chamber 6, a vibration plate 10 that forms a bottom wall of the discharge chamber 6, a concave part that forms a partition 11 that separates the discharge chambers 6, a concave part that forms a common liquid chamber 8, and the like. Has formed. Further, the common liquid chamber 8 is formed so that its volume is 20 times or less of the volume of each discharge chamber 6.
[0016]
The flow path substrate 1 diffuses boron, which is a high-concentration impurity, into a thickness (depth) serving as a diaphragm on a (110) -oriented single-crystal silicon substrate (silicon wafer), and stops etching of the high-concentration boron-doped layer. By performing anisotropic etching as a layer, a diaphragm 10 having a desired thickness is obtained when a concave portion or the like serving as the discharge chamber 6 is formed. Note that gallium, aluminum, or the like can be used as the high-concentration P-type impurity in addition to boron.
[0017]
Further, as a method of forming the diaphragm 10, a diaphragm is formed by forming an N-type layer as a diaphragm on a P-type substrate or a P-type layer as a diaphragm on an N-type substrate and stopping the etching by electrochemical etching. , A method of stopping etching in an oxide film layer using an SOI substrate, a method of controlling time, and ending etching.
[0018]
A concave portion 14 is formed in the electrode substrate 3, and an electrode 15 facing the diaphragm 10 is formed on the bottom surface of the concave portion 14 with a predetermined gap 16 therebetween. Is deformed by electrostatic force to form an actuator section that changes the internal volume of the discharge chamber 6. A gap is formed by joining the electrode substrates 3, and electrodes 15 are arranged at respective positions corresponding to the respective vibration plates 10.
[0019]
Further, the electrode substrate 3 is provided with an ink supply port 9 which is a through hole for supplying ink to the common liquid chamber 8 from outside. In the common liquid chamber 8 of the flow path substrate 1, a through hole 9a is formed at a portion corresponding to the ink supply port 9.
[0020]
On the electrode 15 of the electrode substrate 3, an insulating layer 17 of, for example, 0.1 μm thick SiO ₂ is formed in order to prevent the electrode 15 from being damaged by contact with the vibration plate 10. The electrode 15 is extended to near the end of the electrode substrate 3 to form an electrode pad portion 15a for connecting to an external drive circuit via a connection means.
[0021]
The electrode substrate 3 has a recess 14 formed on a glass substrate or a single crystal silicon substrate having a thermal oxide film 3a formed on its surface by etching with an HF aqueous solution or the like, and the recess 14 has high heat resistance such as titanium nitride. The electrode 15 is formed only in the concave portion 14 by forming a film having a desired thickness by a film forming technique such as sputtering, CVD, or vapor deposition, and then forming and etching a photoresist. The electrode substrate 3 and the flow path substrate 1 are joined by processes such as anodic joining and direct joining.
[0022]
Here, the electrode 15 is formed by sputtering titanium nitride to a thickness of 0.1 μm in a concave portion 14 having a depth of 0.4 μm formed by etching a silicon substrate, and a SiO ₂ sputtered film is formed thereon by 0.1 μm. The insulating layer 17 is formed with a thickness. Therefore, in this head, the length of the air gap 16 (the distance between the diaphragm 10 and the surface of the insulating layer 17) after joining the electrode substrate 3 and the flow path substrate 1 is 0.2 μm.
[0023]
Further, the nozzle plate 4 is formed with a groove serving as the nozzle 5 and the liquid resistance portion 7, and the ejection surface is subjected to a water-repellent treatment. The nozzle plate 4 is formed of a resin member such as polyimide, and is joined to the flow path substrate 1 with an adhesive. The nozzle plate 4 forms a wall surface of the common liquid chamber 8.
[0024]
In this head, the diaphragm 10 is connected to the common electrode, and a lead wire is bonded to the electrode pad 15a, for example, and a driver (not shown) is connected, so that the inkjet head can be driven.
[0025]
Further, by connecting an ink supply pipe to the ink supply port 9 by bonding, the common liquid chamber 8, the discharge chamber 6, and the like are filled with ink supplied from the ink tank (not shown) through the ink supply port 9. It becomes possible. The ink to be used is prepared by dissolving or dispersing a surfactant such as ethylene glycol and a dye or pigment in a main solvent such as water, alcohol and toluene. Furthermore, if a heater or the like is attached to the inkjet head, hot melt ink can also be used.
[0026]
Then, when a positive voltage pulse is applied to the electrode 15 by a driver, for example, and the surface of the electrode 15 is charged to a positive potential, the corresponding lower surface of the diaphragm 10 is charged to a negative potential. Therefore, the diaphragm 10 is attracted by the electrostatic force and bends in a direction in which the distance between the diaphragm 10 and the individual electrode 15 is reduced. At this time, when the diaphragm 10 bends, ink is supplied from the common liquid chamber 8 to the discharge chamber 6 via the fluid resistance 7.
[0027]
Next, when the voltage pulse applied to the electrode 15 is turned off and the stored electric charge is discharged, the diaphragm 10 is restored to the original position. Due to this restoring operation, the internal pressure of the ejection chamber 6 rapidly rises, and the ink droplets are ejected from the nozzles 5 toward the recording paper (not shown).
[0028]
The relationship between the common liquid chamber configuration and the nozzle plate in such a head will be described with reference to FIG.
First, the configuration of the flow path substrate 1 and the electrode substrate 3 was changed as shown in FIGS. 5 and 6 by using a SUS plate having a thickness of 30 μm as the nozzle plate 4 (corresponding portions are shown in FIGS. Above, a frame member 20 for supplying ink was connected to the common liquid chamber 8, and the size of the common liquid chamber 8 was changed to perform an ink ejection experiment.
[0029]
Here, the discharge chambers 6 were arranged in 128 bits at a density of 150 dpi. First, the center bit of the array was driven, and the number of drive bits was gradually increased on both sides. Finally, when all 128 bits were driven, the number of bits at which ejection failure occurred was evaluated. The driving frequency was 16 kHz.
[0030]
This evaluation result is shown in FIG. The common liquid chamber / discharge chamber volume ratio is the ratio of the sum of the volume of the common liquid chamber and the volume of the discharge chamber communicating with the common liquid chamber. The discharge chamber is the volume of the liquid above the area of the pressure generating means, and is the volume of the portion painted with dots in FIG.
[0031]
According to the results shown in FIG. 7, it is understood that when the volume of the common liquid chamber exceeds 20 times the volume of the discharge chamber, discharge failure does not occur. If it is less than 20 times, the pressure wave interferes in the common liquid chamber and affects each discharge chamber. If it exceeds 20 times, the pressure wave is attenuated in the common liquid chamber and no discharge failure occurs.
[0032]
Next, a similar experiment was performed by changing the nozzle plate 4 to a polyimide nozzle plate having a thickness of 30 μm. The nozzle 5 was formed by laser processing. FIG. 8 shows the result at this time.
[0033]
As shown in FIG. 8, when the nozzle plate 4 is made of polyimide, ejection failure can be remarkably reduced. This is because one of the walls of the common liquid chamber 8 is a nozzle plate 4 made of a polyimide having a small rigidity, and that portion functions as a damper for attenuating the pressure wave in the common liquid chamber 8, thereby reducing discharge failure. It is thought that it was done.
[0034]
As described above, by using a member having a small rigidity for the nozzle plate to form a wall of the common liquid chamber, even if the volume of the common liquid chamber is small, a discharge failure can be prevented.
[0035]
Therefore, by using polyimide for the nozzle plate 4 in the ink jet head shown in FIGS. 1 to 4 described above, the same result as that of FIG. 8 is obtained, and even if the common liquid chamber 8 is small, Even when the volume of the discharge chamber was 20 times or less, a head free of discharge failure could be obtained. Therefore, the pressure wave in the common liquid chamber can be attenuated without specially providing a damper mechanism in the common liquid chamber, and discharge failure can be prevented.
[0036]
Here, when the Young's modulus of the nozzle plate is E [N / m ³ ] and the thickness is h [m],
0.00001 [N] ≦ Eh ³ ≦ 0.0006 [N]
It is preferable to satisfy the following relationship.
[0037]
In eh ³ is less than 0.00001 (N), a rigid small discharge energy of the nozzle plate 4 constituting the wall of the discharge chamber 6 is absorbed, the discharge efficiency is lowered, also 0.0006 to (N) If it exceeds, the rigidity of the nozzle plate 4 increases, and a sufficient damper effect cannot be obtained.
[0038]
Further, the thickness of the nozzle plate 4 is preferably 40 μm or less because a minute nozzle is opened, and is preferably 10 μm or more in order to produce a good yield without a defect such as a pinhole. Under these conditions, the Young's modulus is preferably 20 GPa (2E10 [N / m ³ ]) or less.
[0039]
In the above embodiment, polyimide is used for the nozzle plate, but other resins such as polyamide, fluorine-based resin, polyolefin-based resin, PPS, and PET can be used.
[0040]
Next, a second embodiment will be described with reference to FIGS. FIG. 9 is an exploded perspective view of the head according to the embodiment, and FIG. 10 is a cross-sectional view of the head along the longitudinal direction of the diaphragm.
[0041]
In this ink jet head, a flow path plate 21, a vibration plate 22 provided below the flow path plate 21, and a nozzle plate 24 formed of a resin member such as polyimide provided above the flow path plate 21 are laminated and joined. In addition, a plurality of nozzles 25 formed by laser processing form a discharge chamber 26 that communicates through a nozzle communication passage 26a, a common liquid chamber 8 that communicates with the discharge chamber 26 through a fluid resistance portion 27, and the like.
[0042]
In this head, the volume of the discharge chamber is a region (see FIG. 10) that is filled with dots at a portion located on the diaphragm 22. Further, the common liquid chamber 28 is formed such that its volume is 20 times or less the volume of each discharge chamber 26.
[0043]
One end of a piezoelectric element 32 joined to a base substrate 31 such as a ceramic substrate is joined to the outer surface of the vibration plate 22.
[0044]
A frame member 33 is joined to the outer peripheral portion of the diaphragm 22 on the outer peripheral side of the base substrate 31, and an ink supply hole 29 for supplying ink from outside to the common liquid chamber 28 is formed in the frame member 33. In 22, an ink supply port 29 a corresponding to the ink supply hole 29 is formed.
[0045]
The discharge chamber 26 is formed by anisotropic etching using an alkali liquid such as KOH or TMAH using a silicon substrate having a (110) plane orientation for the flow path plate 21. In addition, through-holes that form the nozzle communication passage 26a and the common liquid chamber 28, which are through-holes, are formed by using ICP and anisotropic etching with an alkaline solution in combination. By joining the nozzle plates 24, the upper surface of the common liquid chamber 28 is sealed, and the nozzle plate 24 made of a resin member forms one wall surface of the common liquid chamber 28. The diaphragm 22 used was a nickel plate manufactured by electroforming.
[0046]
In this head, by connecting a driver IC to the piezoelectric element 32 and applying a voltage, the piezoelectric element 32 is displaced to deform the diaphragm 22. Thereby, energy is given to the ink in the ejection chamber 26, and the ink droplet is ejected from the nozzle 25 through the nozzle communication passage 26a.
[0047]
In the present embodiment as well, the nozzle plate 24 forming the wall of the common liquid chamber 28 acts as a damper, attenuates the pressure wave in the common liquid chamber, and prevents defective discharge.
[0048]
Next, a third embodiment will be described with reference to FIG. FIG. 3 is an explanatory cross-sectional view of the head along the longitudinal direction of the diaphragm.
In this head, a flow path 36 was formed by forming a groove on the upper surface of the flow path plate 21, and ink flowed on both surfaces of the flow path plate 22. The discharge chamber volume is a region that is located on the vibration plate 22 and is filled with dots. The other configuration is the same as that of the second embodiment.
[0049]
In this head, high-frequency driving is possible by increasing the flow rate of the ink, and since there is no ink stagnation in the common liquid chamber, the discharge of air bubbles is further improved.
[0050]
Next, a fourth embodiment will be described with reference to FIGS. FIG. 12 is an exploded perspective view of the head according to the embodiment, and FIG. 13 is a cross-sectional view of the head along the longitudinal direction of the diaphragm.
The ejection principle of this head is the same as that of the head of the first embodiment. This head is a laminated structure in which a flow path plate 41, an electrostatic actuator substrate 42, and a nozzle plate 44 made of a resin member such as polyimide are overlapped and joined, and a plurality of nozzles 45 A discharge chamber 46 communicating with the discharge chamber 46a, a common liquid chamber 48 communicating with the discharge chamber 46 via a fluid resistance portion 47, a flow path 56 on the nozzle plate 44 side, and the like are formed.
[0051]
In this head, the volume of the discharge chamber is a region which is filled with dots in a portion located on the diaphragm described later, and the common liquid chamber 28 is formed such that its volume is 20 times or less the volume of each discharge chamber 26. are doing.
[0052]
The electrostatic actuator substrate 42 has, on an insulating film 51 a formed on a base substrate 51, a vibration plate 52 made of polysilicon, and an electrode 54 made of polysilicon opposed to the vibration plate 52 with a predetermined gap 53 therebetween. An actuator unit that changes the inner volume of the discharge chamber 46 by displacing the vibration plate 52 with electrostatic force is configured. The gap 53 is formed by etching and removing a sacrificial layer between the diaphragm 50 and the electrode 54.
[0053]
The electrostatic actuator substrate 42 has an ink supply port 49 which is a through hole for supplying ink to the common liquid chamber 48 from outside.
[0054]
In order to prevent a short circuit on the electrode 54 and / or the vibration plate 52 due to the contact between the electrode 54 and the vibration plate 52, for example, a 0.1 μm-thick insulating layer such as SiO ₂ (not shown). Is formed. Further, an electrode pad portion 54a for extending the electrode 54 to near the end of the base substrate 51 and connecting it to an external drive circuit via a connection means is formed of aluminum.
[0055]
In the electrostatic actuator substrate 42, a gap 53 between the vibration plate 50 and the electrode 54 is formed by etching a sacrificial layer. The electrode pad portion 54a for extending the electrode 54 to the vicinity of the end of the base substrate 51 and connecting it to an external driving circuit via a connecting means is formed of aluminum.
[0056]
Also in the present embodiment, the nozzle plate 44 forming the wall of the common liquid chamber 48 functions as a damper, attenuates the pressure wave in the common liquid chamber, and can prevent discharge failure.
[0057]
In the above embodiments, the side shooter type ejects ink droplets from the nozzle holes provided on the upper surface of the substrate. However, the edge shooter type ejects ink droplets from the nozzle holes provided at the end of the substrate. You can also.
[0058]
Next, the ink cartridge according to the present invention will be described with reference to FIG. The ink cartridge 200 is formed by integrating an ink jet head 202 having any one of the above-described embodiments having a nozzle hole 201 and the like, and an ink tank 203 for supplying ink to the ink jet head 202.
[0059]
As described above, by integrating the ink jet head, which is the droplet discharge head according to the present invention, with the ink tank, there is no need to provide a special damper mechanism, the capacity of the common liquid chamber is not required to be large, and the discharge failure is reduced. Since the head that can be prevented can be integrated, the size and cost can be reduced, and the reliability is improved.
[0060]
Next, an example of the ink jet recording apparatus according to the present invention will be described with reference to FIGS. 15 is an explanatory perspective view of the recording apparatus, and FIG. 16 is an explanatory side view of a mechanism of the recording apparatus.
[0061]
The inkjet recording apparatus includes a carriage movable in the main scanning direction inside the recording apparatus main body 211, a recording head including the inkjet head according to the present invention mounted on the carriage, an ink cartridge for supplying ink to the recording head, and the like. A paper feed cassette (or a paper feed tray) 214 capable of stacking a large number of sheets 213 from the front side is detachably attached to the lower part of the apparatus main body 211. The manual feed tray 215 for manually feeding the paper 213 can be opened, the paper 213 fed from the paper feed cassette 214 or the manual feed tray 215 is taken in, and the printing mechanism 212 After recording the image, the paper is discharged to the paper discharge tray 216 mounted on the rear side.
[0062]
The printing mechanism 212 holds the carriage 223 slidably in the main scanning direction (the direction perpendicular to the paper surface of FIG. 16) by a main guide rod 221 and a sub guide rod 222, which are guide members that are laterally mounted on left and right side plates (not shown). On the carriage 223, a head 224 composed of an inkjet head, which is a droplet discharge head according to the present invention, which discharges ink droplets of each color of yellow (Y), cyan (C), magenta (M), and black (Bk). Are arranged in a direction intersecting the main scanning direction with a plurality of ink ejection ports, and are mounted with the ink droplet ejection direction facing downward. Each ink cartridge 225 for supplying each color ink to the head 224 is exchangeably mounted on the carriage 223. Note that the above-described ink cartridge according to the present invention may be mounted.
[0063]
The ink cartridge 225 has an upper air port communicating with the atmosphere, a lower supply port for supplying ink to the inkjet head, and a porous body filled with ink inside, and a capillary force of the porous body. Maintains the ink supplied to the inkjet head at a slight negative pressure.
[0064]
Although the heads 224 of each color are used here as the recording head, a single head having nozzles for ejecting ink droplets of each color may be used.
[0065]
Here, the carriage 223 is slidably fitted on the main guide rod 221 on the rear side (downstream side in the paper conveyance direction), and is slidably mounted on the front guide rod 222 on the front side (upstream side in the paper conveyance direction). are doing. In order to move and scan the carriage 223 in the main scanning direction, a timing belt 230 is stretched between a driving pulley 228 and a driven pulley 229 which are driven to rotate by a main scanning motor 227. , And the carriage 223 is reciprocated by the forward and reverse rotation of the main scanning motor 227.
[0066]
On the other hand, in order to transport the sheet 213 set in the sheet cassette 214 to the lower side of the head 224, the sheet 213 is guided by the sheet supply roller 231 and the friction pad 232 for separating and feeding the sheet 213 from the sheet cassette 214. A guide member 233, a transport roller 234 that transports the fed paper 213 in a reversed state, a transport roller 235 pressed against the peripheral surface of the transport roller 234, and a leading end that defines a feed angle of the paper 213 from the transport roller 234. A roller 236 is provided. The transport roller 234 is driven to rotate by a sub-scanning motor 237 via a gear train.
[0067]
In addition, a print receiving member 239 is provided as a paper guide member for guiding the paper 213 sent from the transport roller 234 below the recording head 224 corresponding to the moving range of the carriage 223 in the main scanning direction. On the downstream side of the printing receiving member 239 in the paper transport direction, there are provided a transport roller 241 and a spur 242 which are driven to rotate to transport the paper 213 in the paper discharge direction. Rollers 243 and spurs 244 and guide members 245 and 246 forming a paper discharge path are provided.
[0068]
At the time of recording, by driving the recording head 224 according to the image signal while moving the carriage 223, ink is ejected onto the stopped paper 213 to record one line, and after the paper 213 is transported by a predetermined amount, Record the line. Upon receiving a recording end signal or a signal indicating that the rear end of the sheet 213 has reached the recording area, the recording operation is terminated and the sheet 213 is discharged.
[0069]
Further, a recovery device 247 for recovering the ejection failure of the head 224 is disposed at a position outside the recording area on the right end side in the moving direction of the carriage 223. The recovery device 247 has a cap unit, a suction unit, and a cleaning unit. The carriage 223 is moved to the recovery device 247 side during the printing standby, the head 224 is capped by the capping means, and the ejection port is kept wet, thereby preventing ejection failure due to ink drying. In addition, by discharging ink that is not related to printing during printing or the like, the ink viscosity of all the discharge ports is kept constant, and stable discharge performance is maintained.
[0070]
When a discharge failure occurs, the discharge port (nozzle) of the head 224 is sealed with a capping unit, and air bubbles and the like are sucked out of the discharge port with a suction unit through a tube, and ink or dust adhered to the discharge port surface. Is removed by the cleaning means, and the ejection failure is recovered. The sucked ink is discharged to a waste ink reservoir (not shown) provided at a lower portion of the main body, and is absorbed and held by an ink absorber inside the waste ink reservoir.
[0071]
As described above, since the inkjet recording apparatus is equipped with the inkjet head (or ink cartridge) according to the present invention, there is no ejection failure, high reliability, and stable ink droplet ejection characteristics over a long period of time. Thus, high-quality recording can be performed. In addition, the head can be reduced in size and weight, so that the carriage can be operated at a high speed, the printing speed is high, and the motor for driving the carriage can be downsized. It is possible.
[0072]
In the above embodiment, the droplet discharge head according to the present invention is applied to an inkjet head. However, droplets of liquid other than ink, for example, a droplet discharge head for discharging a liquid resist for patterning, a gene analysis sample, The present invention can also be applied to a droplet discharging head for discharging. Further, in each of the embodiments described above, the head using the electrostatic type or the piezoelectric element has been described, but the present invention can be similarly applied to the thermal type head as described above.
[0073]
【The invention's effect】
As described above, according to the droplet discharge head of the present invention, the volume of the common liquid chamber is equal to or less than 20 times the volume of each discharge chamber communicating with the common liquid chamber, and the wall surface of the common liquid chamber is Since the nozzle plate is formed of a resin member, it is possible to prevent a discharge failure with a simple configuration and perform stable droplet discharge.
[0074]
According to the ink cartridge according to the present invention, the droplet discharge head according to the present invention and the ink tank that supplies ink to the head are integrated, so that it is possible to prevent a discharge failure with a simple configuration and achieve stable droplet discharge. A head-integrated cartridge that can be performed can be obtained, and the size and cost can be reduced.
[0075]
According to the inkjet recording apparatus of the present invention, since the inkjet recording apparatus includes the droplet discharge head or the ink cartridge of the present invention, stable droplet discharge can be performed, and high-quality recording can be performed.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view of an ink jet head as a droplet discharge head according to a first embodiment of the present invention,
FIG. 2 is a plan view showing the nozzle plate of the head in a transparent state. FIG. 3 is a schematic cross-sectional view showing the head in a liquid chamber longitudinal direction. FIG. 4 is a schematic view of the head in a liquid chamber short direction. FIG. 5 is an exploded perspective view for explaining a head configuration used for evaluating the relationship between the common liquid chamber / discharge chamber volume ratio and discharge failure. FIG. 6 is a cross-sectional explanatory view of the head configuration. FIG. 8 is an explanatory view for explaining a relationship between a common liquid chamber / discharge chamber volume ratio and a discharge failure when a nozzle plate is a metal member. FIG. 8: A common liquid chamber / discharge chamber volume when a nozzle plate is a resin member. FIG. 9 is an explanatory view for explaining a relationship between a ratio and a discharge failure. FIG. 9 is an exploded perspective view of an inkjet head as a droplet discharge head according to a second embodiment of the present invention.
FIG. 10 is a cross-sectional explanatory view of the head. FIG. 11 is a cross-sectional explanatory view of an ink-jet head as a droplet discharge head according to a third embodiment of the present invention. FIG. 12 is a liquid droplet discharge according to a fourth embodiment of the present invention. Exploded perspective view of an inkjet head as a head,
FIG. 13 is a cross-sectional explanatory view of the head. FIG. 14 is a perspective explanatory view of an ink cartridge according to the present invention. FIG. 15 is a perspective explanatory view illustrating an outline of a mechanism of an ink jet recording apparatus according to the present invention. Explanatory cross-sectional view of the recording apparatus [Description of reference numerals]
DESCRIPTION OF SYMBOLS 1 ... Flow path board, 3 ... Electrode board, 4 ... Nozzle board, 5 ... Nozzle, 6 ... Discharge chamber 7 ... Fluid resistance part, 8 ... Common liquid chamber, 10 ... Vibration plate, 15 ... Electrode, 9 ... Ink supply port .

Claims (6)

A nozzle for discharging droplets, a discharge chamber communicating with the nozzle, a common liquid chamber communicating with each discharge chamber, and pressure generating means for generating pressure for pressurizing the liquid in the discharge chamber; In the droplet discharge head in which a part of the wall surface is formed of a nozzle plate forming the nozzle, the volume of the common liquid chamber is not more than 20 times the volume of each discharge chamber communicating with the common liquid chamber, The droplet discharge head is characterized in that the nozzle plate is a resin member. 2. The droplet discharge head according to claim 1, wherein at least a portion of the nozzle plate serving as a wall of the common liquid chamber has a Young's modulus of E [N / m ³ ] and a thickness of h [m]. A droplet discharge head satisfying 0.00001 [N] ≦ Eh ³ ≦ 0.0006 [N]. 3. The droplet discharge head according to claim 1, wherein a thickness of the nozzle plate is 10 μm or more and 40 μm or less. 4. The droplet discharge head according to claim 1, wherein the Young's modulus of the nozzle plate is 2E10 [N / m ³ ] or less. 5. An ink cartridge in which an ink jet head for discharging ink droplets and an ink tank for supplying ink to the ink jet head are integrated, wherein the ink jet head is the liquid drop discharge head according to any one of claims 1 to 4. And an ink cartridge. An ink-jet recording apparatus for recording an image by discharging ink droplets, comprising: a droplet discharge head according to any one of claims 1 to 4 or an ink cartridge according to claim 5. Recording device.

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