JP2006187922A - Droplet ejection head, ink cartridge equipped with it, and inkjet recording apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide droplet ejection heads which are arranged in two lines in the longitudinal direction of an ejected-liquid storage part in such a manner that nozzle holes, the ejected-liquid storage parts and a pressure changing means are aligned in three or more lines in the short-side direction of the ejected-liquid storage part, and which enable the downsizing of an apparatus and a reduction in material by making an area of a head surface smaller than that of a head surface of a conventional droplet ejection head. <P>SOLUTION: The droplet ejection heads are arranged in two lines in the longitudinal direction of the ejected-liquid storage part 102 in such a manner that diaphragms 110, the storage parts 102 and the nozzle holes 101 are aligned in three or more lines in the short-side direction 3 of the storage part 102; the nozzle holes area arranged in the longitudinal direction of the storage parts 102; the nozzle hole 101 is provided in a place to an end near the other line in the projected plane of the storage part 102 with respect to a head surface 10s in a direction perpendicular to the head surface 10s; and an individual through-hole 103 as an individual supply passage is formed in such a manner as to be elongated from the storage part 102 in the direction of separation from the head surface 10s. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a droplet discharge head that discharges liquid such as ink in the form of droplets, an ink cartridge including the droplet discharge head, and an inkjet recording apparatus.

The ink jet recording apparatus has many advantages such as extremely low noise during recording, high-speed printing, and use of inexpensive plain paper with a high degree of freedom of ink. Among them, a so-called ink-on-demand system that discharges ink droplets only when recording is necessary does not require collection of ink droplets that are not necessary for recording, and has become mainstream. An inkjet head, which is a droplet ejection head used in an image recording apparatus such as a printer, a facsimile machine, a copying apparatus, or an image forming apparatus, includes a nozzle hole that ejects ink droplets, and an ejection that communicates with the nozzle holes. Generated by the pressure generating means, comprising a liquid storage part (also referred to as a pressurized liquid chamber, a pressure chamber, an ink flow path, etc.) and a pressure generating means for generating pressure to pressurize the ink in the discharge liquid storage part The ink droplets are ejected from the nozzle holes by pressurizing the ink in the ejection liquid storage portion with the pressure thus applied.
Examples of such a droplet discharge head include the following.
A piezo type that discharges ink droplets by deforming and displacing a diaphragm forming the wall surface of the discharge liquid storage portion using an electromechanical conversion element such as a piezoelectric element as pressure generating means.
Thermal type that discharges ink droplets by generating bubbles by boiling the ink film using an electrothermal conversion element such as a heating resistor disposed in the discharge liquid container.
An electrostatic type that discharges ink droplets by deforming a diaphragm that forms the wall surface of the discharge liquid storage portion with electrostatic force.
In recent years, lead-free thermal type and electrostatic type have attracted attention due to environmental problems, and many types of electrostatic type that have less influence on the environment from the viewpoint of low power consumption in addition to lead-free have been proposed. Examples of electrostatic droplet discharge heads are described in Patent Documents 1, 2, and 3.
The electrostatic droplet discharge head and the piezo droplet discharge head described above have a plurality of nozzle holes, discharge liquid storage portions, and pressure generating means arranged side by side to store ink to be supplied to the plurality of discharge liquid storage portions. And a separate supply path for supplying ink from the common liquid storage section to each discharge liquid storage section.

JP-A-10-193611 Japanese Patent Laid-Open No. 2002-316418 Japanese Patent Laid-Open No. 2001-10047

However, since the droplet discharge heads described in Patent Document 1 and Patent Document 2 are provided with the individual supply path on the same surface as the discharge liquid storage unit, a space for the individual supply path is required, and the nozzle holes are not provided. There is a problem that the area of the head surface of the provided head surface portion becomes large. With such a configuration, when the nozzle holes, the discharge liquid storage portion, and the pressure generating means are arranged in two rows in the longitudinal direction of the discharge liquid storage portion, this problem becomes significant.
In addition, the droplet discharge head described in Patent Document 3 includes three or more nozzle holes, a discharge liquid storage portion, and pressure generation means arranged in a row in the short direction of the discharge liquid storage portion, and is arranged in the longitudinal direction of the discharge liquid storage portion. Arranged in two rows. And the nozzle hole is provided in the location near the edge part away from the other row | line | column in the projection surface of the discharge liquid accommodating part with respect to the head surface of the direction perpendicular | vertical to a head surface. In an apparatus using a droplet discharge head, in order to prevent droplets from leaking from the nozzle holes during standby, the periphery of the nozzle holes is cleaned and capped after the operation of discharging the droplets is completed. A cleaning member that cleans the periphery of the nozzle hole after the operation is completed includes a wiper blade and a suction cap. The suction cap and the moisture retention cap that prevents the droplets from drying through the nozzle hole are in close contact with the head surface around the nozzle hole. Therefore, a certain amount of space is required from the nozzle hole in order for the suction cap and the moisturizing cap to be in close contact with the head surface. In the liquid droplet head disclosed in Patent Document 3, nozzle holes are provided at positions from the end portion away from the other row in the projection plane with respect to the head surface of the discharge liquid storage portions arranged in two rows. As a result, in addition to the space for the two rows of the discharge liquid storage part, a space for adhering the suction cap and the moisture retaining cap to both ends is required, and there is a problem that the area of the head surface increases.
In addition, although the structure which provided the suction cap and the moisture retention cap separately was demonstrated here, the same problem arises also in the structure where a moisture retention cap has the role of a suction cap.
Thus, when the area of the head surface is increased, the apparatus is increased in size, and more materials for forming the members are required.

  The present invention has been made in view of the above problems, and the object of the present invention is to form three or more nozzle holes, discharge liquid storage portions, and pressure change means in a row in the short direction of the discharge liquid storage portions. The droplet discharge heads arranged side by side and arranged in two rows in the longitudinal direction of the discharge liquid storage portion reduce the size of the device and reduce the material by reducing the area of the head surface compared to the conventional droplet discharge head. It is an object of the present invention to provide a droplet discharge head that can be realized.

In order to achieve the above object, the invention of claim 1 includes a nozzle hole for discharging a droplet, a discharge liquid storage portion that communicates with the outside through the nozzle hole and stores the discharge liquid that becomes the droplet, Pressure changing means for changing the pressure in the discharge liquid storage section, a common liquid storage section for storing the discharge liquid supplied to the plurality of discharge liquid storage sections, and each discharge liquid storage section from the common liquid storage section In a droplet discharge head having an individual supply path for supplying the discharge liquid to the head, a portion provided with a plurality of nozzle holes is a head surface portion, and a surface facing the outside of the head surface portion is a head surface. Nozzle holes, the discharge liquid storage portion, and the pressure change means are arranged in three or more rows in the short direction of the discharge liquid storage portion, and are arranged in two rows in the longitudinal direction of the discharge liquid storage portion. In the projection plane of the discharge liquid storage portion with respect to the head surface in the direction perpendicular to The nozzle hole is provided at a position near the end near the other row, and the individual supply path is formed so as to extend from the discharge liquid storage portion in a direction away from the head surface. is there.
According to a second aspect of the present invention, in the droplet discharge head according to the first aspect, the discharge liquid storage portion is provided on one surface of the droplet discharge head substrate, and the discharge liquid storage portion of the droplet discharge head substrate is provided. The common liquid storage portion is provided on a surface opposite to the provided surface, and the individual supply path is a through hole that communicates the discharge liquid storage portion and the common liquid storage portion. .
According to a third aspect of the present invention, in the liquid droplet ejection head according to the first or second aspect, the individual supply path is formed at the opposite end portion in the longitudinal direction from the nozzle hole formation position of the ejection liquid storage portion. It is a feature.
According to a fourth aspect of the invention, in the liquid droplet ejection head of the first, second or third aspect, the length of the individual supply path is 50 [μm] or more and 700 [μm] or less. It is.
According to a fifth aspect of the present invention, in the liquid droplet ejection head according to the first, second, third, or fourth aspect, the pressure changing means is interposed between the diaphragm constituting the wall surface of the ejection liquid storage section, and the diaphragm and the gap. Electrostatic force that changes the pressure inside the discharge liquid container by applying a voltage between the diaphragm and the counter electrode and deforming the diaphragm by electrostatic force. It is a drive type pressure change means.
According to a sixth aspect of the present invention, in the droplet discharge head of the fifth aspect, a plurality of the diaphragms are provided in one discharge liquid storage portion.
According to a seventh aspect of the present invention, there is provided an ink cartridge in which a droplet discharge head that discharges ink droplets and an ink tank that supplies ink to the droplet discharge head are integrated. The liquid droplet discharge head described in 2, 3, 4, 5 or 6 is used.
According to an eighth aspect of the present invention, in the ink jet recording apparatus equipped with the ink jet head for ejecting ink droplets, the liquid droplet ejection head according to the first, second, third, fourth, fifth or sixth aspect is used as the ink jet head. It is characterized by this.

  In the droplet discharge head according to any one of claims 1 to 8, the nozzle holes, the discharge liquid storage portion, and the pressure changing means are arranged in a line in the short direction of the discharge liquid storage portion in three or more rows. Nozzle holes are provided in two rows in the longitudinal direction and at positions near the other end in the projection plane of the discharge liquid storage portion with respect to the head surface in the direction perpendicular to the head surface. As a result, a space necessary for the cleaning member and the cap member to be in close contact with the head surface is provided between the nozzle hole provided near the end of the discharge liquid storage portion on the head surface near the other end and the end of the head surface. What is necessary is just to secure. This is ensured by the length in the longitudinal direction of the discharge liquid storage portion from the position where the nozzle hole is provided on the head surface. Therefore, it is not necessary to newly provide a space necessary for the cleaning member and the cap member to be in close contact with both ends of the head surface. In addition, the area of the head surface can be reduced as compared with the case where the nozzle holes are provided closer to the end portion away from the other row in the projection plane with respect to the head surface of the discharge liquid storage portions arranged in two rows. Furthermore, the individual supply path is formed so as to extend from the discharge liquid storage portion in a direction away from the head surface. As a result, the space for the individual supply path on the same surface as the discharge liquid storage portion can be reduced, and the area of the head surface can be reduced compared to the case where the individual supply path is provided on the same surface as the discharge liquid storage portion. can do.

  According to the first to eighth aspects of the present invention, the nozzle holes, the discharge liquid storage section, and the pressure change means are arranged in a line in the shape of three or more in the short direction of the discharge liquid storage section, and are arranged in the longitudinal direction of the discharge liquid storage section. With the droplet discharge heads arranged in two rows, the head surface area is reduced as compared with the conventional droplet discharge head, so that the apparatus can be downsized and the material can be reduced. .

Hereinafter, an ink jet printer (hereinafter, printer 31) will be described as an embodiment of an image forming apparatus to which the present invention is applied.
First, the basic configuration of the printer 31 will be described. FIG. 1 is a perspective view of the printer 31. The printer 31 includes a carriage 33 that can move in a direction transverse to the sheet conveyance direction (hereinafter referred to as a main scanning line direction 70) inside the main body indicated by a dotted line in the figure, and a holding unit that holds the carriage 33 movably. It has a printing mechanism section 32 provided with 32a and moving means 32b for moving in the main scanning line direction. The carriage 33 of the printing mechanism section 32 includes ink cartridges 43Y, 43M, 43C, and 43B that store ink liquids as discharge liquids of Y (yellow), M (magenta), C (cyan), and B (black) colors, respectively. It is installed so that it can be replaced. The holding means 32 a has a main guide rod 41 that passes through the carriage 33 and is horizontally mounted on both side surfaces of the main body. Moreover, it has the sub guide rod 42 extended in parallel with this main guide rod 41 at a fixed space | interval. The carriage 33 is supported on the main guide rod 41 and the sub guide rod 42 so as to be movable in the main scanning line direction 70. The moving means 32 b of the carriage 33 includes an endless timing belt 50 having teeth on the inner peripheral surface, a driving pulley 48 that stretches the timing belt 50, and a driven pulley 49. The driving pulley 48 is disposed on one side of the main body, and the driven pulley 49 is disposed on the other side of the main body so that the timing belt 50 extends in parallel with the main scanning line direction 70. The moving unit 32b includes a main scanning motor 47 that rotates the drive pulley 48 forward and backward. The carriage 33 has teeth and meshes with the teeth on the inner peripheral surface of the timing belt. When the driving pulley 48 rotates, the timing belt 50 moves endlessly in the main scanning line direction. The carriage 33 meshes with the inner peripheral surface of the timing belt 50 and moves in the main scanning line direction together with the timing belt 50. The carriage 33 can reciprocate in the main scanning line direction by rotating the driving pulley 48 forward and backward by the main scanning motor 47.

  The printing mechanism section 32 is provided with a recovery device 67 that accommodates the carriage 33 during non-image formation at the right end in FIG. The recovery device 67 is provided with a cap device (not shown) and a cleaning device. At the end of image formation, the wiper blade of the cleaning device rubs the head surface to scrape off dirt around the nozzle holes. During non-image formation, the nozzle hole on the head surface is capped by the cap device to keep the nozzle hole wet. Thereby, it is possible to prevent ejection failure due to drying of ink near the nozzle hole. Further, the cleaning device is provided with suction means. The cleaning device has a function of keeping the viscosity at the same viscosity as the used ink by discharging ink that has not been used for image formation during the image formation from the nozzle hole and sucking it by the suction means. Thereby, the ink viscosity of each head part can be made constant, and a favorable image can be obtained. Further, when a discharge failure occurs, the nozzle hole on the head surface is sealed by the capping unit, and the discharge failure is recovered by sucking out bubbles and dust attached to the nozzle hole together with the ink by the suction unit of the cleaning device. The sucked ink is discharged to a waste tank (not shown) disposed at the lower part of the main body. By providing such a recovery device 67, ejection failure can be suppressed, stable ejection characteristics can be obtained, and a good image can be maintained.

FIG. 2 is a schematic cross-sectional view of the yellow ink cartridge 43Y when viewed from the main scanning line direction 70 of the printer 31. As shown in FIG. As shown in FIG. 2, the printer main body has a paper feed mechanism section 34 in addition to the print mechanism section 32. The paper feed mechanism section 34 includes a paper feed section 34 a on which sheets are stacked, and a transport section 34 b that transports the paper in the paper feed section to the paper discharge tray 36 via a position facing the print mechanism section 32. I have. The paper feed unit 34 a of the paper feed mechanism unit 34 includes a paper feed tray 37 that stacks a large number of sheets and is detachably attached to the main body 31. The paper feed unit 34a includes a paper feed roller 51 and a friction pad 52, and transports the paper in the paper feed tray 37 to the transport unit 34b. Further, the printer 31 is provided with a manual feed tray 35 so that paper can be fed manually, and is attached to the apparatus main body 31 so as to be able to be turned over. The sheet on the manual feed tray 35 is conveyed to the conveyance roller 54 by the manual feed roller 57.
The transport unit 34b includes a guide member 53 that guides the paper fed from the paper feed tray 37, and a transport roller 54 that transports the paper to a position facing the head unit 44Y as a droplet discharge head. Further, a conveyance roller 55 that presses the sheet against the conveyance roller 54 and a leading end roller 56 that feeds the sheet to a position facing the head unit 44Y at a predetermined angle are provided. The transport roller 54 is rotated clockwise in the figure by a sub-scanning motor (not shown). A printing receiving member 59 for guiding paper is provided at a position facing the head portion 44Y. Further, a discharge roller 61 and a spur 62 for discharging the sheet on which the image is recorded to the discharge tray 36, and a pair of guide members 65 that form a discharge path are provided.

  FIG. 3 is a schematic configuration diagram of the yellow ink cartridge 43Y. The ink cartridge 43Y mounted on the carriage 33 has a head portion 44Y having nozzle holes and a tank portion 45Y that stores ink and supplies ink to the head portion 44Y. Further, as shown in FIG. 2, the ink cartridge 43Y includes an air port 46Y communicating with the air on the upper surface of the tank portion 45Y. In addition, a supply port 40 </ b> Y that supplies ink liquid from the tank unit 45 to the head unit 44 is provided inside the ink cartridge 43. In the above description, the yellow ink cartridge 43Y has been described as an example, but the same applies to ink cartridges of other colors. Further, although the ink cartridge in which the head portion 44 and the tank portion 45 are integrated has been described, the tank portion 45Y and the head portion 44Y may be separated. In FIGS. 1 and 2, the head portion 44Y installed downward is drawn upward in FIG. 3 for convenience of explanation.

  Next, the printing operation of the printer 31 will be described. A signal such as image information is sent from the personal computer, and printing is executed. First, paper is fed from the manual feed tray 35 or the paper feed tray 37 to the transport unit 34b by a paper feed roller. The paper fed from the paper feed tray 37 is guided by the guide member 53 and the transport roller 55, reversed, and transported to a position facing the head portion 44Y. On the other hand, the paper supplied from the manual feed tray 35 is guided to the transport roller 55 and transported to a position facing the head unit 44. When the sheet conveyed to the head unit 44 reaches a predetermined position, the conveyance roller 54 is stopped to stop the movement of the sheet. Then, the carriage 33 does not reciprocate in the main scanning line direction according to the image signal, but a predetermined ink liquid is ejected to a predetermined position of the stopped paper to form one line on the paper. Here, one line means a range in the sub-scanning line direction (the moving direction of the recording paper at a position facing the head unit 44) in which the head unit 44 can record on the paper. When the recording for one line is completed in the main scanning line direction, the transport roller 54 is driven for a predetermined time, and the sheet is moved by one line in the direction of the paper discharge tray 36 to stop. The carriage 33 reciprocates in the main scanning line direction according to the image signal, but forms an image for one line. Such a process is repeated a predetermined number of times to print a desired image on paper. The sheet on which the desired image is printed is conveyed by the sheet discharge roller 61 and the spur 62 and discharged to the sheet discharge tray 36. After the image formation, the carriage 33 moves to the recovery device 67 on the right side in FIG. 1 and caps the nozzle holes of the head with a cap device (not shown).

Next, the head unit 44 will be described. In the following description, the head portion of the Y ink cartridge will be described as an example, but the same applies to the head portions 44 of other colors. For convenience of explanation, the color code is omitted.
FIG. 4 is an exploded perspective view for explaining the head portion 44, and a part thereof is shown in a sectional view. 5 is an explanatory view of the head portion 44 in an assembled state, FIG. 5 (a) is a plan view, and FIG. 5 (b) is a cross-sectional view at the position X1-X2 in FIG. 5 (a). FIG. 5C is a cross-sectional view at the position of Y1-Y2 in FIG. The head portion 44 has a laminated structure in which a nozzle substrate 10 as a head surface portion provided with a plurality of nozzle holes 101 for discharging ink liquid and an actuator substrate 20 as a droplet discharge head substrate are stacked. FIG. 5A is a plan view seen through the nozzle substrate 10, and only the installation positions of the nozzle holes 101 provided in the nozzle substrate 10 are indicated by broken lines. The head portion 44 is an example of a side shooter type in which ink droplets are ejected from a plurality of nozzle holes 101 provided in the nozzle substrate 10. Hereinafter, the outer surface side of the nozzle substrate 10 provided with the nozzle holes 101 of the head portion 44 is referred to as a head surface 10s.

In the actuator substrate 20, a groove portion having a V-shaped cross section formed by four surfaces of the crystal orientation surface 111 is formed on the silicon substrate of the crystal orientation surface 100. On the insulating film 111 formed on the V-shaped groove, an individual electrode 109 and a diaphragm 110 as pressure changing means are formed by a laminated film through a gap 120.
A sacrificial layer (details will be described later) on the assumption that the gap will be removed later is formed as a laminated film in the same manner as the individual electrode material and the diaphragm material, and the sacrificial layer is removed from the sacrificial layer removal hole 107 later. By forming. The V-shaped groove serves as a discharge liquid storage portion 102 having two diaphragms 110 as bottom walls. An individual through hole 103 serving as a fluid resistance portion for supplying ink to each discharge liquid storage portion 102 and a common liquid storage portion 104 provided on the back side of the actuator substrate 20 communicate with each other. The common liquid storage section 104 is supplied with ink liquid from a supply port 40Y that supplies the ink liquid of the tank section 45 to the head section 44, and is supplied to each discharge liquid storage section 102 through each individual through hole 103. Supply. Further, the nozzle substrate 10 to be bonded to the upper surface of the actuator substrate 20 is made of a resin film having a thickness of 50 μm, and nozzle holes 101 are provided on the surface portion of the actuator substrate 20 so as to communicate with the respective discharge liquid storage portions 102. ing.
The above-described fluid resistance portion is set to have a high resistance to fluid so that the pressure does not escape to the common liquid storage portion 104 when ink is ejected from the nozzle hole 101 due to a change in pressure in the discharge liquid storage portion 102. Part. Specifically, the cross-sectional area is made smaller than that of the common liquid storage unit 104 and the discharge liquid storage unit 102, and the length thereof is designed to be long in order to reduce variation in resistance value.

Next, a method for creating the head unit 44 will be described. The head unit 44 forms the actuator substrate 20 by processing the silicon substrate of the crystal orientation plane 100 and forming the electrode material and the diaphragm material.
6A to 6J are explanatory diagrams of a procedure for creating the head unit 44. FIG. As shown in FIG. 6A, a mask oxide film 22 serving as a mask material for anisotropic etching is formed on the surface of the silicon substrate 21 by 0.5 μm, and opening patterning is performed on the groove forming portion by photolithography. At this time, anisotropic etching using 25% TMAH solution is performed. Since the silicon substrate 21 having the crystal orientation plane 100 is used, the etching stops at the crystal orientation plane 111, and a V-shaped groove having an inclination of 54.7 degrees is formed as shown in FIG. 6B. . After forming the V-shaped groove, the mask oxide film 22 is removed by HF wet etching.

Next, with respect to the silicon substrate 21 from which the mask oxide film 22 has been removed, as shown in FIG. 6C, 1.0 μm of an insulating film 111 is formed on the entire surface of the silicon substrate 21 by thermal oxidation again. Next, as shown in FIG. 6C, 0.5 μm of P-doped polysilicon to be the individual electrode 109 is formed. After the individual electrode 109 is patterned by the lithoetch method, an HTO film having a thickness of 0.2 μm is formed on the surface of the individual electrode 109 as an insulating film. In the drawing, the insulating film of HTO is omitted. Further, after forming 0.35 μm of polysilicon as the sacrificial layer 201 in the gap forming portion, the sacrificial layer 201 is patterned by photolithography as shown in FIG. After the patterning of the sacrificial layer 201, as shown in FIG. 6 (f), HTO is formed as an insulating film with a thickness of 0.1 μm, the P-doped polysilicon layer 110a serving as a common electrode is 0.2 μm, and then the diaphragm is protected. As an insulating film to be a film, a Si ₃ N ₄ film of 0.1 μm and HTO of 0.3 μm are formed. In the drawing, the insulating films of HTO and Si ₃ N ₄ are omitted. The four layers of HTO (0.1 μm), P-doped polysilicon (0.2 μm), Si ₃ N ₄ film (0.1 μm), and HTO (0.3 μm) function as the laminated diaphragm 110. Thereafter, as shown in FIG. 6G, a sacrificial layer removal hole 107 is formed in a region to be a partition wall between the V-shaped grooves by lithoetching, and etching is performed in the order of the insulating film and the P-doped polysilicon layer 110a serving as a common electrode. Do.

  Next, as shown in FIG. 6H, a pattern of the common liquid storage portion 104 is formed on the back surface of the actuator substrate 20 that is a silicon substrate by lithoetching. Here, a vertical opening pattern is formed by an ICP dry etcher using SF6 and C2F4 gases. The etch depth is etched to a depth that leaves the fluid resistance of the individual through-hole 103, which is an individual supply path to be formed later. Further, the individual through-holes 103 that become fluid resistance are patterned from the front surface by a lithoetch method, and the common liquid storage portion 104 formed on the back surface is connected to the discharge liquid storage portion 102 formed on the front surface. The common liquid container 104 may be formed by anisotropic wet etching at the same time for the front and back by patterning an oxide film serving as a mask material for anisotropic etching when the V-shaped groove is first formed.

  Thereafter, oxidation is performed to form an oxide film on the side surface of the P-doped polysilicon layer 110a serving as the common electrode exposed on the side surface of the sacrificial layer removal hole 107, the individual through-hole 103, and the side surface of the common liquid storage portion 104. Further, the sacrificial layer removal hole 107 is patterned by lithoetching, and the insulating film at the bottom of the sacrificial layer removal hole 107 is removed by etching. Thereafter, an electrode lead-out wiring and a metal pad 106 of the P-doped polysilicon layer 110a to be the individual electrode 109 and the common electrode are formed. Then, the sacrificial layer 201 is removed from the sacrificial layer removal hole 107 by isotropic dry etching using SF6, and the actuator substrate 20 is completed by forming the gap 120 as shown in FIG. Here, the sacrificial layer 201 made of polysilicon is surrounded by an oxide film, so that the sacrificial layer can be removed under a sacrificial layer etching condition with high selectivity to the oxide film, and the gap can be formed with high accuracy. it can.

By attaching a polyimide film as the nozzle substrate 10 having nozzle holes formed on the surface of the completed actuator substrate 20, a head portion 44 as a droplet discharge head is completed as shown in FIG. 6 (j).
As described above, most of the steps for producing the droplet head can be produced by a method used in the manufacture of semiconductors, so that the droplet discharge head can be produced with high yield and low cost. This is because the film can be formed by diffusion / CDV, patterning by the lithography process, and processing by the etching process, all of which can be performed in a clean environment, so that the method can be manufactured with a high yield and high reliability.

Here, empirically, it is better to set the fluid resistance to 5E13 (Pa · s / m ³ ) or less, and the length of the individual through hole 103 is set so that the silicon substrate 21 is easily processed and the chip area is not increased. It is desirable that it is 700 um or less.
FIG. 7 is a diagram for explaining the dimensions of the individual through-holes 103. Table 1 shows the relationship between the length of the individual through-holes 103 in the dimensions shown in FIG. An equation for obtaining the value of fluid resistance is shown in Equation 1.

ここで、ａ及びｂは長方形管の２辺の長さ、ｌは長方形管の管の長さ、μは長方形管を通過する流体の粘度である。

Here, a and b are the lengths of the two sides of the rectangular tube, l is the length of the rectangular tube, and μ is the viscosity of the fluid passing through the rectangular tube.

From Table 1, it can be seen that as the length of the fluid resistance is shorter, the processing variation of the through hole is greatly affected, and the variation of the fluid resistance is increased. Therefore, the length of the individual through hole 103 is preferably 50 μm or more in order to make the variation in fluid resistance approximately 50% or less, and further 100 μm or more in order to ensure the strength of the actuator substrate 20. Some are most desirable.
Further, the position of the individual through hole 103 is preferably set at a position away from the position where the nozzle hole 101 is formed in the discharge liquid storage portion 102. As shown in FIG. 8, by providing the individual through-hole 103 at a position away from the position where the nozzle hole 101 is formed in the longitudinal direction, the flow of ink in the ejection liquid container is smoothed and the ejection performance is stabilized. Furthermore, it is most preferable to form it on the opposite side in the longitudinal direction of the discharge liquid storage portion 102 as shown in FIG. This is because if the individual through hole 103 and the nozzle hole 101 are located as far as possible, the flow of ink in the discharge liquid storage section becomes smoother and the discharge performance is stabilized.

Next, the operation of the actuator of the head unit 44 will be described.
When a voltage is applied to the individual electrode 109 of the actuator substrate 20 of the head portion 44 and the P-doped polysilicon layer 110a as a common electrode of the diaphragm 110, a negative charge is supplied to the P-doped polysilicon layer 110a. A positive charge is supplied to the electrode 109. As a result, an electrostatic force is generated between the P-doped polysilicon layer 110a and the individual electrode 109, and the diaphragm 110 having the P-doped polysilicon layer 110a moves to the individual electrode 109 side by this electrostatic force. Then, the diaphragm 110 is deformed and the volume of the discharge liquid storage unit 102 is increased. As a result of an increase in the volume of the discharge liquid storage section 102, the discharge liquid storage section 102 has a negative pressure and flows into the discharge liquid storage section 102 from the common liquid storage section 104 through the individual through hole 103. When the voltage applied to the individual electrode 109 and the P-doped polysilicon layer 110a is set to 0, the charged electric charges are discharged through the respective circuits, and the individual electrode 109 and the P-doped polysilicon layer 110a are discharged. The electrostatic force disappears. As a result, the diaphragm 110 returns to the original position, and the volume of the discharge liquid storage unit 102 decreases. As a result, the pressure in the discharge liquid storage unit 102 increases, and the ink liquid is discharged from the nozzle hole 101. In the above description, a negative charge is supplied to the P-doped polysilicon layer 110a and a positive charge is supplied to the individual electrode 109. However, a positive charge is supplied to the P-doped polysilicon layer 110a and the individual electrode 109 is supplied. A negative charge may be supplied to 109.

Next, the head surface 10s of the droplet discharge head (hereinafter referred to as an example) employed in the present embodiment and a conventional droplet discharge head (hereinafter referred to as Comparative Examples 1 to 3) in FIG. 9 is used. Compare areas. In order to equalize the performance of ejecting liquid droplets, the longitudinal dimension of the ejection liquid storage section is unified at 600 μm. FIG. 9A is a cross-sectional view of the droplet discharge head according to the embodiment, in which the discharge liquid storage portions 102 are arranged in two rows in the longitudinal direction, and the projection surface onto the head surface 10s of the discharge liquid storage portions 102 arranged in two rows. A nozzle hole 101 is provided at a location near the end near the other row. Furthermore, in the direction away from the discharge liquid storage portion 102 from the head surface 10s, here, an individual through-hole 103 as an individual supply path is provided below the bottom of the discharge liquid storage portion 102. A common liquid storage portion 104 that stores ink liquid supplied through the individual through-holes 103 is provided on the surface of the actuator substrate 20 opposite to the surface on which the discharge liquid storage portion 102 is provided. Further, at both ends of the head surface 10s, a width of 130 μm and a width of 300 μm of the metal pad 106 are secured as end joints.
In addition, about the arrangement | positioning of the nozzle hole 101, the discharge liquid accommodating part 102, and the diaphragm 110, you may provide in the object about the junction part of the member center of the discharge liquid accommodating part 102 located in a line with 2 rows, but by staggered arrangement | positioning , The dot width can be narrowed, and high image quality can be achieved.
The size of the individual through-hole 103 that functions as a fluid resistance portion is 40 [μm] × 60 [μm] × 300 [μm], and the ink viscosity is 5.0 [mPa · s]. The value of the fluid resistance Rf is 1.32E + 13 [Pa · s / m ³ ].

FIG. 9B is a cross-sectional view of the droplet discharge head of Comparative Example 1. Since the individual supply path 103a and the common liquid storage section 104 are provided on the same surface as the discharge liquid storage section 102 and are arranged in two rows in the longitudinal direction of the discharge liquid storage section 102, as compared with the embodiment. The head surface 10s is very wide. When the nozzle holes 101, the discharge liquid storage portion 102, and the diaphragm 110 configured in Patent Document 1 or 2 are arranged in two rows in the discharge liquid storage portion longitudinal direction, the head portion as in Comparative Example 1 shown in FIG. 44.
The size of the individual supply path 103a having a function as a fluid resistance portion is 60 [μm] × 60 [μm] × 700 [μm], and the ink viscosity is 5.0 [mPa · s]. The value of the fluid resistance Rf is 1.28E + 13 [Pa · s / m ³ ].

FIG. 9C is a cross-sectional view of the droplet discharge head of Comparative Example 2. Unlike Comparative Example 1, the common liquid storage unit 104 is provided not in the same plane as the discharge liquid storage unit 102 but in the vertical direction. Thereby, compared with the comparative example 1, the width | variety of a head surface can be narrowed for the common liquid accommodating part 104 minutes. However, since the individual supply path 103a is provided on the same surface as the discharge liquid storage portion 102, the head surface is wider than that of the embodiment.
The size of the individual supply path 103a having a function as a fluid resistance portion is 60 [μm] × 60 [μm] × 700 [μm], and the ink viscosity is 5.0 [mPa · s]. The value of the fluid resistance Rf is 1.28E + 13 [Pa · s / m ³ ].

FIG. 9D is a cross-sectional view of the droplet discharge head of Comparative Example 3. Unlike the comparative examples 1 and 2, the common liquid storage unit 104 and the individual supply path 103a are provided not in the same plane as the discharge liquid storage unit 102 but in the vertical direction. As a result, the width of the head surface can be reduced by an amount corresponding to the individual supply path 103a as compared with Comparative Example 2. However, the nozzle hole 101 and the metal pad 106 have a space for the capping mechanism and the wiping mechanism for removing ink adhering to the periphery of the nozzle hole to adhere to the surface of the nozzle substrate 10 in order to prevent the nozzle hole 101 from being dried and to keep it in a wet state. It is necessary to provide between. In the configuration of the comparative example 3, the nozzle hole 101 is provided at a position near the end away from the other row in the projection surface of the discharge liquid storage unit 102 with respect to the head surface 10s in the direction perpendicular to the head surface 10s. Therefore, it is necessary to provide the distance necessary for the above-described space further outside the nozzle holes 101 provided at both ends in the two projection planes with respect to the head surface 10s of the discharge liquid storage portion 102 provided in two rows of the head surface 10s. . Therefore, the head surface is wider than that of the embodiment by the distance to be secured from the nozzle hole 101 to the metal pad 106. The configuration of Patent Literature 3 is a head portion as in Comparative Example 3 shown in FIG.
The size of the individual supply path 103a having a function as a fluid resistance portion is 40 [μm] × 60 [μm] × 300 [μm], and the ink viscosity is 5.0 [mPa · s]. The value of the fluid resistance Rf is 1.32E + 13 [Pa · s / m ³ ].
Also for the droplet discharge head of the example, it is necessary to provide a distance necessary for capping or wiping the nozzle hole 101 on the head surface as in Comparative Example 3. However, since the nozzle hole 101 is provided at a position near the end near the other row in the projection surface of the discharge liquid storage unit 102 with respect to the head surface 10s in the direction perpendicular to the head surface 10s, the nozzle hole 101 is connected to the metal pad. The distance to be secured up to 106 is secured by the length of the discharge liquid storage portion 102, and it is not necessary to provide a new space.

  Here, for Example, Comparative Example 1, Comparative Example 1, Comparative Example 2 and Comparative Example 3, the required length in the width direction of each part, the width of the head surface in the case of 300 dpi, and one droplet discharge part (table Table 2 shows the area required for providing 1 medium bit). The length in the longitudinal direction of the head portion required for the 1-bit droplet discharge portion is 84.5 μm.

From Table 2, the comparative example 2 shown in FIG. 9C is provided with the common liquid storage portion 104 in the vertical direction, so that the head is larger than the liquid droplet ejection head of the comparative example 1 shown in FIG. The area of the surface can be reduced by about 36%. Furthermore, in the embodiment shown in FIG. 9A in which the individual supply path having the function as the fluid resistance portion is formed by the individual through-hole 103, the area of the head surface is larger than that of the droplet discharge head of Comparative Example 1. Can be reduced by about 59%.
Further, in the embodiment shown in FIG. 9A, the nozzle hole 101 is provided at a position near the end near the other row in the projection surface of the discharge liquid storage portion 102 with respect to the head surface 10s in the direction perpendicular to the head surface 10s. Therefore, it is not necessary to provide a new space between the nozzle hole 101 and the metal pad 106, and the area of the head surface is about 24% smaller than that of the comparative example 3 shown in FIG. can do.
Further, although not shown, an individual supply path 103a and a common liquid storage section 104 are provided on the same surface as the discharge liquid storage section 102, and the discharge liquid storage section 102 for the head surface 10s in a direction perpendicular to the head surface 10s. Consider a configuration in which the nozzle hole 101 is provided at a location near the end away from the other row in the projection plane. There is a possibility that the droplet discharge head of the embodiment can reduce the area of the head surface by about 64% at the maximum as compared with the droplet discharge head having such a configuration. Further, the length, width, and depth of the discharge liquid storage portion 102 are the same in all configurations of the example, the comparative example 1, the comparative example 2, and the comparative example 3. Therefore, the droplet discharge head of the embodiment can reduce the area of the head surface while keeping the discharge liquid storage portion 102 at the same capacity, that is, while maintaining the performance of discharging ink.
Thus, by reducing the area of the head surface, the droplet discharge head can be reduced in size. In addition, material can be reduced, leading to cost reduction.
In the above-described embodiment, a liquid droplet ejection head that employs an electrostatic actuator that changes the volume in the ejection liquid storage portion by turning on and off the voltage applied to the fixed electrode and the electrode provided on the diaphragm is described. did. The method of changing the volume in the discharge liquid storage unit is not limited to the electrostatic method, and a piezoelectric actuator using a piezoelectric element that deforms when a voltage is applied may be employed.
Further, in the above-described embodiment, an example in which the present invention is applied to an inkjet head that ejects ink as a droplet ejection head has been described. However, an apparatus to which the above-described droplet discharge head can be applied is not limited to an inkjet head. As a droplet discharge head other than an inkjet head, for example, it can be applied to other droplet discharge heads such as a droplet discharge head that discharges a liquid resist as droplets and a droplet discharge head that discharges a DNA sample as droplets. .

As described above, according to the present embodiment, the nozzle holes 101, the discharge liquid storage unit 102, and the vibration plate 110 as the pressure change unit are arranged in a row in the lateral direction of the discharge liquid storage unit 102 in three or more rows. Are arranged in two rows in the longitudinal direction, and nozzle holes 101 are provided at positions close to the end portion near the other row in the projection surface of the discharge liquid storage portion 102 with respect to the head surface 10s in the direction perpendicular to the head surface 10s. . The nozzle holes 101 are provided on the end side near the other row in the projection plane of the discharge liquid storage portion 102 arranged in two rows, that is, on the center side of the head surface. This eliminates the need for extra space for capping and wiping the nozzle holes 101 at both ends of the outer head surface 10 s at both ends of the discharge liquid storage portions 102 arranged in two rows away from the other row. . Further, in the direction away from the discharge liquid storage portion 102 from the head surface 10s, here, an individual through hole 103 as an individual supply path having a function as fluid resistance is provided below the bottom of the discharge liquid storage portion 102. Thereby, it is not necessary to provide a space for arranging the individual supply path on the same surface as the discharge liquid storage unit 102. With these configurations, the area of the head surface can be reduced as compared with the conventional droplet discharge head.
In addition, since most of the steps for producing the head portion 44 can be produced by a method used in semiconductor manufacturing, a droplet discharge head can be produced with good yield and low cost. Further, the discharge liquid storage portion 102 is provided on one surface of the actuator substrate 20 as a droplet discharge head substrate, and the common liquid storage portion 104 is provided on the back side of the discharge liquid storage portion 102 of the actuator substrate 20. An individual through hole 103 as an individual supply path is a through hole that allows the discharge liquid storage unit 102 and the common liquid storage unit 104 to communicate with each other. Thereby, a droplet discharge part can be easily produced from one silicon substrate using the construction method used in semiconductor manufacturing.
In the head portion 44, the individual through hole 103 is formed at an end portion on the opposite side to the position where the nozzle hole 101 is formed in the long side direction in the discharge liquid storage portion 102. By using the individual through-hole 103 as a fluid resistance, a space for newly arranging the fluid resistance portion becomes unnecessary, and the area of the head surface can be reduced. Further, by forming the individual through-hole 103 at the end opposite to the position where the nozzle hole 101 is formed, the ink flow in the discharge liquid storage portion 102 becomes smooth, and stable droplet discharge becomes possible. Thereby, a high-quality droplet discharge head can be produced at low cost.
In addition, the length of the individual through hole 103 which is an individual supply path having a function as fluid resistance is set to 300 μm. By setting the length of the fluid resistance to 50 [μm] or more and 700 [μm] or less, the processing of the individual through holes 103 is facilitated. Furthermore, since the fluid resistance value of the individual through hole 103 does not become too large, the diameter of the through hole can be reduced, and space saving can be achieved. Due to space saving, a droplet discharge head can be produced at low cost.
The head unit 44 is an electrostatically driven droplet discharge head that discharges droplets by applying pressure to the liquid by deforming the diaphragm 110 as pressure generating means by electrostatic force. Therefore, most processes can be created by a method used in semiconductor manufacturing, and a highly reliable droplet discharge head can be produced with a high yield and low cost.
In addition, since the electrostatically driven head unit 44 includes a plurality of diaphragms 110 that constitute the wall surface in the discharge liquid storage unit 102, the volume excluded by the vibration plate displacement can be increased, and the area of the discharge liquid storage unit 102 can be reduced. . Thereby, a highly reliable droplet discharge head can be produced at low cost.
In addition, since the head portion 44 that is an ink jet head and the ink tank that supplies ink to the ink jet head are integrated, manufacturing defects can be reduced and the cost can be reduced.
Further, since the printer 31 as the ink jet recording apparatus is equipped with the head portion 44 as an ink jet head, manufacturing defects can be reduced and the cost can be reduced.

[Modification 1]
In the above-described embodiment, the discharge liquid storage portion 102 and the common liquid storage portion 104 are provided on the two surfaces of a single silicon substrate and communicated with each other through the individual through holes 103. The configuration for communicating with the common liquid storage unit 104 is not limited to this. FIG. 10 shows a schematic explanatory diagram of the first modification.
In the first modification, a through-hole serving as a fluid resistance is provided over the frame member 301 bonded to the silicon substrate 21 and the back surface of the substrate, instead of being formed with only one silicon substrate. And the common liquid accommodating part 104 is provided in the frame member 301 side. In this manner, by providing the frame member 301 on the back surface of the silicon substrate 21 to create the actuator substrate, it is possible to create a liquid droplet ejection head having a higher strength than that produced only with the silicon substrate.

  In the above-described embodiment and Modification 1, an example of an electrostatic actuator in which an actuator is created in a V-shaped groove has been described. However, as shown in FIG. Is obtained.

1 is a schematic perspective view of an ink jet printer. 1 is a schematic sectional view of an ink jet printer. FIG. 2 is a schematic configuration diagram of an ink cartridge. FIG. 3 is a schematic perspective view of a head portion of an ink cartridge. FIG. 3 is a schematic explanatory diagram of a head portion of an ink cartridge. (A) is a top view, (b) and (c) are sectional views. (A)-(j) is explanatory drawing of the preparation procedure of a droplet discharge head. The dimension explanatory drawing of a fluid resistance part. FIG. 6 is a schematic explanatory diagram of a configuration in which a through hole is provided at a position different from that in FIG. 5. (A) is a top view, (b) is sectional drawing. Schematic which compares the difference in an area by the difference in a structure of a droplet discharge head. (A) is an Example, (b) is the comparative example 1, (b) is the comparative example 2, (b) is the schematic of the comparative example 3. FIG. FIG. 6 is a schematic configuration diagram of a head unit according to Modification 1; The schematic block diagram of the head part which made the bottom face of the discharge liquid accommodating part flat.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Nozzle board | substrate 20 Actuator board | substrate 32 Printing mechanism part 33 Carriage 34 Paper feed mechanism part 35 Manual feed tray 36 Paper discharge tray 37 Paper feed tray 44 Head part 50 Timing belt 51 Paper feed roller 57 Manual feed roller 67 Recovery device 101 Nozzle hole 102 Discharge liquid Container 103 Individual through hole 103a Individual supply path 104 Common liquid container 106 Metal pad 107 Sacrificial layer removal hole 109 Individual electrode 110 Diaphragm 110a P-doped polysilicon layer 111 Insulating film 120 Gap 201 Sacrificial layer

Claims (8)

Nozzle holes for discharging droplets;
A discharge liquid storage portion that communicates with the outside through the nozzle hole and stores the discharge liquid that becomes the liquid droplets;
Pressure changing means for changing the pressure in the discharge liquid storage section;
A common liquid storage section for storing the discharge liquid supplied to the plurality of discharge liquid storage sections;
In a droplet discharge head having an individual supply path for supplying the discharge liquid from the common liquid storage section to each of the discharge liquid storage sections,
When a portion provided with a plurality of the nozzle holes is a head surface portion, and a surface facing the outside of the head surface portion is a head surface,
The nozzle holes, the discharge liquid storage part, and the pressure change means are arranged in a row of three or more in the short direction of the discharge liquid storage part, and arranged in two rows in the longitudinal direction of the discharge liquid storage part,
The nozzle hole is provided at a location near the end near the other row in the projection surface of the discharge liquid storage unit with respect to the head surface in a direction perpendicular to the head surface,
A droplet discharge head, wherein the individual supply path is formed so as to extend from the discharge liquid storage portion in a direction away from the head surface. The droplet discharge head according to claim 1.
The discharge liquid storage portion is provided on one surface of the droplet discharge head substrate,
The common liquid container is provided on the surface of the droplet discharge head substrate opposite to the surface on which the discharge liquid container is provided,
A droplet discharge head, wherein the individual supply path is a through-hole that communicates the discharge liquid storage part and the common liquid storage part. The droplet discharge head according to claim 1 or 2,
The droplet discharge head, wherein the individual supply path is formed at an end portion on the opposite side in the longitudinal direction from the position where the nozzle hole is formed in the discharge liquid storage portion. The droplet discharge head according to claim 1, 2 or 3,
The droplet discharge head, wherein the length of the individual supply path is 50 [μm] or more and 700 [μm] or less. The droplet discharge head according to claim 1, 2, 3, or 4
The pressure change means comprises a diaphragm constituting a wall surface of the discharge liquid storage section and a counter electrode opposed to the diaphragm through a gap;
An electrostatic drive type pressure changing means for applying a voltage between the diaphragm and the counter electrode and deforming the diaphragm by electrostatic force to change the pressure inside the discharge liquid storage unit; A droplet discharge head that is characterized. The droplet discharge head according to claim 5.
A droplet discharge head comprising a plurality of the vibration plates in one discharge liquid container. In an ink cartridge in which a droplet discharge head that discharges ink droplets and an ink tank that supplies ink to the droplet discharge head are integrated,
An ink cartridge using the droplet discharge head according to claim 1, 2, 3, 4, 5, or 6 as the droplet discharge head. In an inkjet recording apparatus equipped with an inkjet head that ejects ink droplets,
An ink jet recording apparatus using the liquid droplet ejection head according to claim 1 as the ink jet head.

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