JP3213859B2 - Ink jet recording head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording apparatus for forming an ink image on a medium such as recording paper by flying ink droplets, and more particularly, to an on-demand ink jet head having a plurality of nozzles. Regarding the structure.

[0002]

2. Description of the Related Art Conventional ink jet recording heads are disclosed in JP-A-3-187775 and JP-A-3-288.
No. 648, Japanese Patent Application Laid-Open No. 1-115638, and U.S. Pat. No. 4,439,780 are known.

In Japanese Patent Laid-Open Publication No. 3-187775, FIG.
As shown in FIG. 2, an ink jet recording head is formed by laminating a base block made of a piezoelectric element, a cover plate member, and a flow path block made of a Si base material. In particular, the piezoelectric element is alternately divided for driving and for supporting the flow path block. The supporting base block supports the partition wall of the flow path block via the cover plate member. Since the driving piezoelectric element and the supporting piezoelectric element are formed in the process of dicing the piezoelectric element, the configuration is simplified and the cost can be reduced.

In Japanese Patent Application Laid-Open No. 3-288648, FIG.
As shown in FIG. 3, a groove formed in the piezoelectric element is filled with an elastic body. By reducing the elastic modulus of the elastic body near the deformed portion of the piezoelectric element in the groove, crosstalk due to propagation of vibration through the elastic body can be reduced.

[0005]

The above-described conventional ink jet recording head has a structure in which a partition wall of a pressure chamber is supported by a supporting piezoelectric element or a filled elastic body. But,
In the conventional example of JP-A-3-187775, since the partition walls are supported only by the piezoelectric elements, when all of the driving piezoelectric elements arranged in a row are simultaneously driven, the supporting force is insufficient and the entire flow path block is base. There is a problem that the robot moves away from the block. Further, there is a problem that the influence of the driving of one driving piezoelectric element propagates as the movement of the entire flow path block, and disturbs the flying form of the ink droplet ejected from another nozzle. Further, in the conventional example of Japanese Patent Publication No. 3-288648, a soft elastic body is provided around the elastic body, so that the ink droplet is joined to the elastic body under the influence of the pressure generated inside the pressure chamber when the ink droplet is caused to fly. There is a problem that the partition wall moves in the direction of the nozzle plate. In addition, since the soft elastic body faces the pressure chamber as one of the components of the pressure chamber, there is also a problem that the rigidity compliance of the pressure chamber increases.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a partition wall which is deformed by a high pressure generated in a pressure chamber in a process of flying ink droplets. An object of the present invention is to provide an ink jet type recording head which is excellent in printing quality and free from crosstalk.

[0007]

According to the present invention, there is provided an ink jet recording head comprising: a piezoelectric element having one end fixed to a base and a pressure plate fixed to the other end;
A pressure chamber corresponding to the pressure chamber, a partition partitioning the pressure chamber, a nozzle communicating with the pressure chamber, an ink supply port communicating with the pressure chamber, a flexible member separating the pressure chamber and the pressure plate, and a piezoelectric element. First and second frames arranged in parallel on both sides of the row, facing the partition between the first and second frames and the flexible member, and integrally fixed via the flexible member And a bridge member.

Further, another ink jet recording head according to the present invention has a piezoelectric element arranged with one end fixed to a base and the other end fixed to a pressure plate, one for one corresponding to the piezoelectric element. Pressure chamber, a partition partitioning the pressure chamber, a nozzle provided at one end of the pressure chamber in communication with the pressure chamber, and a supply provided in the other end of the pressure chamber in communication with the pressure chamber. A mouth, a flexible member partitioning the pressure chamber and the pressure plate, and first and second rows arranged in parallel on both sides of the row of the piezoelectric elements.
An ink jet recording head having a second frame, wherein one surface of the pressure chamber at a portion where the nozzle communicates faces the first frame via the flexible member and the elastic plate. It is characterized by the following.

[0009]

According to the above construction of the present invention, the partition wall partitioning the pressure chamber is supported from the first frame having high rigidity to the second frame. Further, the partition has a laminated structure of a nozzle plate, a partition, a flexible member, and an elastic plate. Therefore, in the process of driving the driving piezoelectric element and causing the ink droplets to fly from the nozzles, the pressure vibration generated inside the pressure chamber can be supported by the bending rigidity of the partition, and as a result, the deformation of the partition is substantially suppressed. Can be suppressed. At the same time, the deformation of the adjacent pressure chamber can be substantially suppressed.

[0010]

FIG. 1 is a perspective view of an ink jet recording apparatus equipped with an ink jet recording head according to a first embodiment of the present invention. The ink jet recording head 1 (hereinafter, referred to as a head) is installed to face the transfer drum 3. The head 1 is mounted on a carriage 5 and is configured to be intermittently movable in the axial direction of the drum 3 along a carriage guide shaft 6. The ink supply pipes 4, 4, 4, and 4 are connected to the back of the head 1 to supply ink from an ink tank (not shown). The drum 3 is provided with a drum shaft 2. The drum shaft 2 is connected to a drum rotation motor (not shown). The fixing roller 8 is parallel to the axial direction of the drum 3 and is close to the drum 3. A fixing roller shaft 9 is provided at both ends of the fixing roller 8, and is configured so as to be separated from and connected to the drum 3 by operating a separating means (not shown). The recording paper 7 is configured to be discharged from the gap between the drum 3 and the fixing roller 8 via the paper feed rollers 10 and 11. A series of operations for forming an ink image on the recording paper 7 will be described. While rotating the drum 3, ink droplets fly from the head 1 to the surface of the drum 3 to form an ink image. The head 1 is intermittently fed along the carriage guide shaft 6 each time the drum 3 makes one rotation. After an ink image is formed on the entire surface of the drum 3, the recording paper 7 is fed into the gap between the drum 3 and the fixing roller 8, and the contact / separation means is operated to sandwich the recording paper 7 between the fixing roller 8 and the drum 3. . The ink image on the surface of the drum 3 is transferred onto the surface of the recording paper 7 while rotating the drum 3 in the direction of arrow 12 and the fixing roller 8 in the direction of arrow 13. With the above configuration and operation, the inkjet recording apparatus of the present embodiment can form a clear image without blurring on the recording paper surface.

FIG. 2 is an exploded perspective view of the ink jet recording head according to the first embodiment of the present invention. Piezoelectric element 21
Are arranged in a row on the upper surface of the base 20. The piezoelectric element 21
After being fixed to the base 20, it is divided by a dicing saw. The piezoelectric element 21 is a stacked piezoelectric element in which thin plates made of a piezoelectric material and electrode plates are alternately stacked in a sandwich shape. External electrodes are formed on the side surfaces of the piezoelectric element 21. One of the external electrodes is electrically connected to one of the electrodes sandwiching the piezoelectric material, and the other external electrode is electrically connected to the other of the sandwiched electrodes. According to this laminated piezoelectric element, the distance between the electrodes can be made as small as possible, so that the voltage of the drive signal can be reduced. A common electrode is provided on one side surface 36 of the base 20 over the entire surface, and is electrically connected to one external electrode of the piezoelectric elements 21, 21, 21. A plurality of segment electrodes are provided on the other side surface 37 of the base 20, and the segment electrodes and the other external electrodes of the piezoelectric element 21 are in one-to-one correspondence.
Are electrically connected. The electrodes provided on the side surfaces 36 and 37 are electrically connected to a drive circuit via a flexible wiring board (not shown). Base 20
Is made of an elastic member having a large acoustic impedance so that the piezoelectric element 21 vibrates reliably. Reference numeral 27 denotes a channel plate, which is made of aluminum, resin, or alumina. The channel plate 27 has two concave portions 25 and 26.
Are provided in parallel. The recesses 25 and 26 are in communication with the ink supply pipe 4 and serve to supply ink to the pressure chamber 35. A first frame 23 and a second frame 24 are provided inside the recesses 25 and 26 in parallel. The first and second frames 23 and 24 are a part of the flow path plate 27 and also a part of the constituent members forming the recesses 25 and 26. First and second frames 2
A vibrator unit including the base 20 and the piezoelectric element 21 is inserted into the gap between 3 and 24. The side surfaces 36 and 37 of the base 20 and the first and second frames 23 and 24 are firmly fixed with an adhesive. The top 38 of the piezoelectric element 21 and the upper surfaces 39 of the first and second frames are configured to be substantially coplanar. Reference numeral 22 denotes an elastic plate made of a metal plate such as nickel or stainless steel having a thickness of 20 to 100 μm. The elastic plate 22 is firmly joined to the upper surface 39 of the flow path plate 27 by an adhesive or the like. The bridge 14 is provided on the elastic plate 22. Reference numeral 41 denotes a pressure plate, which is made of a metal plate such as nickel or stainless steel having a thickness of 20 to 100 μm, like the elastic plate 22. The pressure plate 41 is firmly joined to the top 38. 28 is a flexible member having a thickness of 10 to 1
It is made of a polyimide film of 00 μm or a metal foil of nickel or stainless steel having a thickness of 1 to 30 μm. The flexible member 28 is joined to the pressure plate 41 and the elastic plate 22.
Notches 29 and 30 corresponding to the recesses 25 and 26 are formed in the flexible member 28. Reference numeral 31 denotes a spacer made of a stainless steel material having a thickness of 10 to 200 μm or an elastic material having a longitudinal elastic modulus of 10 × 10 ¹⁰ Pa or more. A hole 40 and a partition 32 are formed in the spacer 31 by etching. The spacer 31 is firmly joined to the flexible member 28 such that the hole 40 corresponds to the pressure plate 41 and the partition 32 corresponds to the bridge 14 of the elastic plate 22. 33 is a nozzle plate having a thickness of 30 to 2
00 μm stainless steel or longitudinal elastic modulus 10 × 10 ¹⁰
It is made of an elastic material of Pa or more. Nozzle plate 33
Are provided with nozzles 34, 34, 34,... By pressing. The diameter of the opening of the nozzle 34 is Φ30
６０60 μm. The nozzle plate 33 is firmly joined to the spacer 31 such that the nozzles 34, 34, 34,... Arranged in a straight line correspond to the holes 40, 40, 40,. I have.

FIGS. 3 (a) and 3 (b) show cross-sectional structures in the nozzle opening arrangement direction of the above-described ink jet recording head. The pressure chamber 35 is partitioned in the horizontal direction by a partition wall 32 of a spacer 31. FIG. The upper and lower portions are sealed by a nozzle plate 33 and a flexible member 28. The pressure chamber 35 has a nozzle opening 34 formed in a nozzle plate 33 and a piezoelectric element 2 fixed to the base 20.
1 are facing each other. The tip of the piezoelectric element 21 contacts the flexible member 28 via the pressure plate 41 to expand the pressure generating chamber 35,
It can be contracted. Pressure member 4
Bridges 14, both sides of which are supported by the upper surface 39 of the flow path plate 27, are disposed between 1 and 41 so as to face the partition 32 of the spacer 31. For this reason, the flexible member 28
The lower surface is sandwiched between the partition wall 32 and the bridge 14 formed on the elastic plate 22. The nozzle plate 33, the partition wall 32, the flexible member 28, and the bridge 14 are integrally and firmly adhered to each other by an adhesive, and the bridge 14 is spaced apart from the frame 24 by a narrow space such as a piezoelectric element through hole. On both sides of the upper surface 39 of the channel plate 27
And is firmly fixed by an adhesive with a sufficient area. For this reason, since the partition 32 and the bridge 14 function integrally as a so-called I-beam, the deformation direction of the piezoelectric element 21 despite the small thickness thereof, that is, the dimension in the arrangement direction of the nozzle openings. Extremely high strength and strong bending rigidity. As a result, the arrangement pitch of the nozzle openings becomes smaller in order to increase the resolution, and sufficient bending rigidity can be provided even if the dimensions in the lateral direction of the bridge, that is, the arrangement direction of the nozzle openings have to be reduced. Becomes

FIG. 4 is a partial plan view of an ink jet type recording head for explaining the first embodiment of the present invention in further detail, and first and second frames 23 and 24 are provided for simplicity. Pressure plate 41, flexible member 28, and spacer 31
Only extracted and shown. Hole 4 of spacer 31
Are rectangular openings, one end of which is in communication with the recess 25, and the other end of which is in communication with the recess 26.
The partition 32 is firmly joined from the upper surface 39 of the first frame 23 to the upper surface 39 of the second frame 24. Reference numeral 43 denotes a supply port, which is a communicating portion between the recess 25 and the pressure chamber 35. 44 is also a supply port, and the recess 26 and the pressure chamber 35
It is a communication part. The pressure chamber 35 refers to a region between the supply port 43 and the supply port 44 and surrounded by the nozzle plate 33, the partitions 32, 32, and the flexible member 28.

Next, the operation for flying the ink droplets of the head 1 will be described. In the standby state, a voltage is applied to the piezoelectric element 21. In a state where a voltage is applied, the piezoelectric element 21 extends in the laminating direction of the piezoelectric material. When a print request is issued, the voltage applied to the piezoelectric element 21 is gradually reduced. As the voltage decreases, the piezoelectric element 21 contracts gradually. As a result, the flexible member 28 inside the pressure chamber 35 is displaced away from the nozzle plate 33, and the pressure chamber 35 is expanded and deformed. The ink is drawn from the supply ports 43 and 44 and the nozzle 34 toward the inside of the pressure chamber 35 with the expansion deformation. As the next step, the reduction of the voltage applied to the piezoelectric element 21 is stopped. As a result, the movement of the piezoelectric element 21 stops. However, since the kinetic energy of the ink flowing from the supply ports 43 and 44 is larger than the kinetic energy of the ink flowing in the direction drawn from the nozzle 34, the flow direction of the ink is from the supply ports 43 and 44 toward the nozzle 34. It becomes inertial flow. This is because the portion where the nozzle meniscus has been drawn has been replaced with gas from ink. At the timing when the nozzle meniscus once pulled back returns to the nozzle opening due to the inertial flow in the direction of the nozzle 34, the application of voltage to the piezoelectric element 21 is started gradually. With the application of the voltage, the piezoelectric element starts to expand and deform, and the pressure chamber 35 contracts and deforms.
Along with this deformation, an ink droplet having a spherical tip from the nozzle 34 flies vigorously. The head 1 of the present embodiment has a configuration in which rigidity compliance is small because the partition wall has high bending rigidity, and has a feature of having a Helmholtz resonance frequency of 100 kHz or more. Therefore, the ink inside the pressure chamber 35 follows the expansion and contraction deformation of the piezoelectric element 21 well,
Experiments have confirmed that the inertial flow is easy to develop. In the conventional head, the supply of the same amount of ink as the flying ink droplets is performed for 100 to 200 μsec by the capillary force of the meniscus of the nozzle 34 in the conventional head, whereas in the head 1 of the present embodiment, the inertial force is From 5 to 20
This is performed in a short time of μsec. For this reason, the head 1 of the present embodiment has a feature that the speed and volume of the continuously flying ink droplets do not change even when driven at a driving frequency of 10 to 50 kHz. U.S. Pat. No. 4,459,601 has a detailed description of the Helmholtz resonance frequency, and a description thereof will be omitted.

When the piezoelectric element 21 contracts and expands, ink flows inside the pressure chamber 35. At the same time when the ink flow is generated, 1 to 10
A high pressure of atmospheric pressure is generated. A state in which the forces are balanced when the piezoelectric element 21 is expanded will be described. In this case, a force for increasing the distance between the flexible member 28 and the base 20 is generated inside the piezoelectric element 21. At the same time, as described above, a large pressure is generated inside the pressure chamber 35, so that a force acts to substantially move the nozzle plate 33 away from the base 20. In the case of a head in which the rigidity of the components from the base 20 to the nozzle plate 33 is insufficient, the nozzle plate 33 bends and deforms as the pressure plate 28 deforms. In addition, the nozzle plate 33 having a high bending rigidity is assumed.
However, since the rigidity of the other members is insufficient even if the base plate 20 is used, a deformation occurs such that the base 20 and the nozzle plate 33 are kept away in a parallel state. As a result, not only the deformation of the piezoelectric element 21 does not sufficiently lead to the deformation of the pressure chamber 35, but also a high pressure cannot be generated inside the pressure chamber 35, and the speed and volume of the formed ink droplets decrease. Problem arises. further,
There is a problem that the adjacent pressure chambers 35 are simultaneously deformed, and the speed of the ink droplets flying from the adjacent nozzles 34 is changed. This is a serious problem in the case of the head 1 in which a large number of nozzles 34 are arranged, and particularly in the case of a so-called line head in which the nozzles 34 are arranged over a length substantially equal to the printing width of the recording paper 7. Notable. However, in the head 1 of the present embodiment, since the rigidity of the structure from the nozzle plate 33 to the base 20 is high, the above problem does not occur. The head 1 of the present embodiment is configured to support the deformation force inside the pressure chamber 35 through two paths described below. The first path extends from the base 20 to the first and second frames 23, 2
4, a path leading to the nozzle plate 33 via the elastic plate 22, the flexible member 28, and the partition 32. The second route is the base 2
0 to the first and second frames 23 and 24, bridge 1
4. Nozzle plate 33 through flexible member 28 and partition 32
It is a route to reach. When the distance between the adjacent pressure chambers 35 is reduced to form the high-density head 1, the width of the partition wall is reduced, and the rigidity of the gap between the first frame 23 and the second frame 24 is reduced. It tends to decrease. However, in the head 1 of the present embodiment, the partition portion is the nozzle plate 3
3, the partition wall 32, the flexible member 28, and the bridge 14, the partition wall portion has a high bending rigidity. In general, it is known that the bending stiffness is effective by the cube of the thickness and the cube of the Young's modulus. Further, in the configuration of the head 1 according to the present embodiment, the partition portion is firmly joined to the first and second frames. Therefore, the joint can be regarded as a completely fixed end, and can be equivalently regarded as a fixed beam at both ends. Therefore, in the above-described second path, the bending rigidity of the partition portion acts as a deformation support member for the nozzle plate 33. Therefore, it is understood that the deformation supporting force of the nozzle plate 33 increases as the length of the partition wall portion decreases.

The head 1 according to the first embodiment having the above-described structure.
Also has the feature that rigidity compliance is small. If the rigidity compliance is small, the Helmholtz resonance frequency of the head 1 can be increased, and the response to the driving frequency and the flying speed of the ink droplet can be improved. If the Helholtz resonance frequency is small,
The ink inside the pressure chamber 35 can follow the high-speed movement of the piezoelectric element 21, so that the ink droplet can fly at high speed. The Helmholtz resonance frequency of the head 1 of the present embodiment is 100 kHz or more, and even when the driving piezoelectric element 21 is driven in a short time of about 10 μsec, the vibration based on the Helmholtz resonance frequency does not overshoot and vibrate. Since vibration does not occur, as described above, the head 1 of this embodiment is characterized in that the speed and volume of continuously flying ink droplets do not change even when driven at a driving frequency of 10 to 50 kHz.

FIG. 5 is a sectional view of an ink jet recording head according to a second embodiment of the present invention. The second embodiment differs from the first embodiment in that a driving piezoelectric element 50 and a supporting piezoelectric element 51 are provided instead of the piezoelectric element 21. Driving piezoelectric element 50 and supporting piezoelectric element 51
Are arranged alternately. Driving piezoelectric element 5
One end of O is joined to the base 20 and the other end is joined to the pressure plate 41. One end of the supporting piezoelectric element 51 is joined to the base 20 and the other end is joined to the bridge 14. The feature of the second embodiment is that the partition is supported by the supporting piezoelectric element 51. In the head 1 according to the present embodiment, the partition wall is more strongly supported by the bending rigidity and the rigidity of the supporting piezoelectric element 51 described in the first embodiment, and therefore, the pressure generated in the pressure chamber 35 is reduced. It has a very strong structure with almost no deformation.

FIG. 6 is a sectional view of an ink jet recording head according to a third embodiment of the present invention. FIG. 7 is a sectional view in the arrangement direction of the piezoelectric elements 21 of the ink jet recording head of the third embodiment. The third embodiment differs from the first embodiment in that the number of supply ports 54 communicating with the pressure chambers 35 is changed from two to one. A concave portion 55 is formed in the flow path plate 53. A first frame 56 and a second frame 57 arranged in parallel on the flow path plate 53 are arranged.
Is provided. A vibrator unit configured by arranging the piezoelectric elements 21 in a row on the upper surface of the base 20 includes a first frame 56.
And the second frame 57 are firmly joined by being inserted into the gap. The pressure chamber 35 includes the nozzle plate 33 and the spacer 3.
1 and a flexible member 28. The nozzle 34 formed in the nozzle plate 33 is connected to the end 5 of the pressure chamber 35.
8. The other end of the pressure chamber 35 has a supply port 5
4 and communicate with a concave portion 55 serving as an ink flow path. The operation method of the head 1 of the third embodiment is the same as that of the first embodiment. Therefore, when the piezoelectric element 21 is expanded and contracted, a high pressure of 1 to 10 atm is generated inside the pressure chamber 35. However, according to the configuration of the head 1 of the present embodiment,
Deformation such that the distance between the nozzle plate 33 and the base 20 changes due to the generated force of the piezoelectric element 21 and the generated pressure inside the pressure chamber 35 does not substantially occur. This is because the path from the base 20 to the nozzle plate 33 is the first from the base 20,
Second frames 56 and 57, elastic plate 22, flexible member 2
8, a first path from the base 20 to the nozzle plate 33 via the partition 32, and first and second frames 56, 57,
This is because it is firmly supported by the second path leading to the nozzle plate 33 via the bridge 14, the flexible member 28, and the partition 32. As in the head 1 of this embodiment, the pressure chamber 35
In the configuration in which the nozzles 34 are provided at the end portions 58, the pressure in the vicinity of the end portions 58 at the time of discharging the ink droplets becomes the maximum pressure. This is because the watershed flowing inside the pressure chamber 35 in the direction of the nozzle 34 and the direction of the supply port 54 is located near the end 58. In the head 1 of the present embodiment, the end 58 is located at a position directly supported by the second frame 57 via the flexible member 28 and the elastic plate 22, so that the pressure chamber 35 in the vicinity of the end 58 with respect to the generated pressure is generated. Almost no elastic deformation occurs due to sufficiently strong rigidity. A head 1 having a supply port 54 at one end of the pressure chamber 35 and a nozzle 34 at the other end.
In this case, it is preferable that the end 55 provided with the nozzle 34 face the second frame 57.

FIG. 8 is a sectional view of an ink jet recording head according to a fourth embodiment of the present invention. FIG. 9 is a sectional view in the arrangement direction of the piezoelectric elements 21 of the ink jet recording head of the fourth embodiment. The head 1 of the present embodiment is structurally characterized in that the vibrator units are configured to face each other. A recess 62, a first frame 64, and a second frame 65 are formed in the channel plate 60 in parallel. A vibrator unit is inserted and fixed in the gap between the first and second frames 64 and 65. The channel plate 61 has a recess 6.
3, the first frame 66 and the second frame 67 are formed in parallel. A vibrator unit is inserted and fixed in the gap between the first and second frames 66 and 67. The pressure plate 74, the flexible member 72,
The spacer 71, the intermediate elastic plate 70, the spacer 71, the flexible member 72, and the pressure plate 74 are sequentially laminated and fixed. The spacer 71 has a comb-teeth shape in which notches serving as partition walls 73 and pressure chambers 68 and 69 are alternately arranged. In the nozzle plate 33, the drilled nozzles 34 are arranged in two rows. The nozzle plate 33 is joined to the side surfaces of the second frames 65 and 67 so that the nozzles 34 arranged in two rows correspond to the pressure chambers 68 and 69. Pressure chamber 6
8, 69 are respectively a flexible member 72, an intermediate elastic plate 70,
The partition wall 73 is formed by being surrounded by the nozzle plate 33. The partition is a bridge 75, a flexible member 72, and a partition 7
3, since the intermediate elastic plate 70, the partition wall 73, the flexible member 72, and the bridge 75 are laminated, the head 1 of the present embodiment also has a strong structure against the pressure generated when the ink droplet flies. The head 1 according to the present embodiment includes the pressure chambers 68 and 6.
No. 9 has no bent portion in which the nozzles 34 are linearly arranged. In the head 1 of this embodiment, the intermediate elastic plate 7
By increasing the thickness of 0, the rigidity of the walls constituting the pressure chambers 68 and 69 can be increased. However, the intermediate elastic plate 70
If the rigidity of the path from the base to the base 20 is not strong, the displacement of the piezoelectric element 21 becomes the displacement of the base 20, and the pressure chambers 68 and 69 cannot be sufficiently deformed. However, in the head 1 of the present embodiment, the flexible member 72, the partition wall 73, the intermediate elastic plate 70
The partition part is constituted by lamination of the above members. Therefore, by fixing both ends of this partition wall so that the first frames 61 and 64 and the second frames 65 and 67 are sandwiched, the head 1 of the present embodiment can prevent the ink droplets from flying when flying. The head 1 has high rigidity and is not displaced in a direction in which the intermediate elastic plate 70 and the base 20 are separated from each other. Pressure chamber 6
In a configuration in which the nozzles 8 and 69 face each other at a narrow interval corresponding to the thickness of the intermediate elastic plate 70, the interval between the rows of the nozzles 34 arranged in a row becomes narrow, so that a small-sized nozzle cap member can be used and airtightness can be achieved. And an ink jet recording apparatus having excellent maintainability can be obtained. Further, in addition to the configuration in which the pressure chambers 68 and 69 are symmetrical via the intermediate elastic plate as in the present embodiment, the pressure chamber 68 and the partition wall 73 face each other with the intermediate elastic plate 70 interposed therebetween, that is, It is also possible to configure so that the nozzles 34 arranged in two rows are arranged in a staggered manner. In this case, since the deformation of the pressure chamber 68 due to the pressure is not transmitted to the opposing pressure chamber 69 via the intermediate elastic plate 70, the intermediate elastic plate 7
Thus, it is possible to configure the head 1 having a reduced thickness of 0. It is also possible to configure the head 1 in which the nozzles 34 are arranged in only one row. In this case, it is possible to increase the thickness of the intermediate elastic plate 70 indefinitely. By combining this with a configuration in which the path from the base 20 to the intermediate elastic plate 70 has high rigidity as in this embodiment, the Helmholtz resonance frequency can be extremely increased. Is obtained.

In the configuration in which the nozzles 34 are provided at the ends of the pressure chambers 68 and 69 as in the head 1 of the fourth embodiment, the pressure at the ends becomes the maximum pressure. Since the end of the head 1 of this embodiment is at a position directly supported by the second frames 65 and 67 via the flexible member 72 and the elastic plate 76, the pressure chamber 68 near the end with respect to the generated pressure, 69
Has a sufficiently high rigidity. A head 1 having a supply port at one end of the pressure chambers 68 and 69 and a nozzle 34 at the other end.
Then, the end where the nozzle 34 is disposed is connected to the second frame 6.
It is desirable to be configured to face 5, 67.

FIG. 10 is an exploded perspective view of an ink jet recording head according to a fifth embodiment of the present invention. FIG.
It is sectional drawing of the arrangement direction of the piezoelectric element 21 of the inkjet type recording head of 5th Example. Head 1 of this embodiment
Is different from the first embodiment in that the tip of the piezoelectric element 21 is directly joined to the flexible member 28. The piezoelectric element 21 is fixed so as to be inserted into a hole of the elastic plate 22 surrounded by the bridge 14. In the head 1 of the present embodiment, the thickness of the elastic plate 22 can be made approximately equal to the length of the piezoelectric element 21. Therefore, the head 1 of the fifth embodiment has a configuration in which rigidity compliance is smaller than that of the first embodiment. Also, the elastic plate 2
In the case where the length of the piezoelectric element 2 is made equal to the length of the piezoelectric element 22 and the bridge 14 of the elastic plate 22 is joined to the base 20, a highly rigid head can be realized.

[0022]

According to the ink jet recording head of the present invention, there is provided a piezoelectric element having one end fixed to a base and a pressure plate fixed to the other end, and a pressure element corresponding to the piezoelectric element in a one-to-one correspondence. A chamber, a partition partitioning the pressure chamber, a nozzle communicating with the pressure chamber, an ink supply port communicating with the pressure chamber, a flexible member partitioning the pressure chamber from the pressure plate, And a first and a second frame disposed therein.
By having a bridge member facing the partition between the second frame and the flexible member and being integrally fixed via the flexible member, the partition has a high bending rigidity and thus has a small rigidity compliance. In addition, there is an effect that the ink inside the pressure chamber follows the expansion and contraction deformation of the piezoelectric element well, the inertial flow is easily developed, and the speed and volume of the ink droplets continuously flying can be made uniform.

[Brief description of the drawings]

FIG. 1 is a perspective view of an inkjet recording apparatus equipped with an inkjet recording head according to a first embodiment of the present invention.

FIG. 2 is an exploded perspective view of the ink jet recording head according to the first embodiment of the present invention.

FIGS. 3A and 3B are a cross-sectional view of the ink jet recording head according to the first embodiment of the present invention in a nozzle row direction and a perspective cross-sectional view showing a cross section on a nozzle row line.

FIG. 4 is a plan view for explaining a configuration of a partition wall portion of the ink jet recording head according to the first embodiment of the present invention.

FIG. 5 is a cross-sectional view of an ink jet recording head according to a second embodiment of the present invention in a nozzle row direction.

FIG. 6 is a sectional view of an ink jet recording head according to a third embodiment of the present invention.

FIG. 7 is a sectional view of an ink jet recording head according to a third embodiment of the present invention in a direction in which piezoelectric elements are arranged.

FIG. 8 is a sectional view of an ink jet recording head according to a fourth embodiment of the present invention.

FIG. 9 is a sectional view of an ink jet recording head according to a fourth embodiment of the present invention in a direction in which piezoelectric elements are arranged.

FIG. 10 is an exploded perspective view of an ink jet recording head according to a fifth embodiment of the present invention.

FIG. 11 is a sectional view of an ink jet recording head according to a fifth embodiment of the present invention, taken in a direction in which nozzles are arranged.

FIG. 12 is a cross-sectional view of a conventional ink jet recording head.

FIG. 13 is a cross-sectional view of a conventional ink jet recording head.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ink jet recording head (head) 3 Drum 7 Recording paper 14 Bridge 20 Base 21 Piezoelectric element 22 Elastic plate 23 First frame 24 Second frame 27 Flow path plate 28 Flexible member 31 Spacer 32 Partition wall 33 Nozzle plate 34 Nozzle 35 Pressure chamber 41 Pressure plate

Claims (1)

(57) [Claims] A piezoelectric element having one end fixed to a base and a pressure plate fixed to the other end;
A pressure chamber corresponding to the pressure chamber, a partition partitioning the pressure chamber, a nozzle communicating with the pressure chamber, an ink supply port communicating with the pressure chamber, and a flexible member partitioning the pressure chamber and the pressure plate. And first and second frames arranged in parallel on both sides of the row of the piezoelectric elements, facing the partition between the first and second frames and the flexible member, and An ink jet recording head having a bridge member fixed integrally with a member.