JP2002307716A - Imaging head and imaging apparatus comprising it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet head having a mechanism for sustaining operation of an apparatus, e.g. initial filling operation, surely by eliminating a suction pump and a valve unit being employed in a prior art ink jet head. SOLUTION: In an imaging head having an electrostatic drive means comprising a nozzle 102, a pressure chamber 113 communicating with the nozzle, a fluid resistive section 114 communicating with a common liquid chamber 115, a diaphragm 112 provided in the pressure chamber 113, and a discrete electrode 131 facing the diaphragm and ejecting an ink drop 16 from the nozzle 102 by deforming the diaphragm 112 to perform recording, a diaphragm 116 made of a thin plate and an electrode 132 facing the diaphragm 116 are provided on the bottom of the common liquid chamber 115.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet head for forming an image, and more particularly to a copier, a facsimile,
The present invention relates to an improvement in an ink jet head used in an image forming apparatus such as a printer and an image forming apparatus incorporating the improved head, and more particularly to a technique for initially filling a recording head with ink when an ink cartridge is replaced.

[0002]

2. Description of the Related Art In an ink jet recording apparatus, in order to maintain the same conditions as during use in a distribution process, ink is charged in a pressure generating chamber to discharge the ink from a nozzle opening. Measures have been taken to prevent drying and ingress of dust. For this reason, an operation of removing the product liquid filled in the recording head prior to the start of use, that is, a so-called initial filling operation of ink is required. In addition, in order to simplify the ink supply operation, the ink is generally housed in a cartridge, and is configured so that the ink can be supplied by being attached to and detached from the recording head. For this reason, there is a problem that the air easily enters the recording head with the replacement of the cartridge, flows into the pressure generating chamber, weakens the pressing force, and deteriorates the recording quality. In order to solve such a problem, it is necessary to perform an ink filling operation in which airtightness is maintained at the time of initial filling of ink or replacement of the ink cartridge. Japanese Patent Application Laid-Open No. 10-119318 is known as a conventional technique relating to such ink filling. In this publication, an ink jet recording head 7 that receives ink supply from an ink cartridge 8 and discharges ink droplets from nozzle openings of a nozzle plate in accordance with recording data, and dries the nozzle openings by resiliently contacting the nozzle plate. , A suction pump 11 for supplying a negative pressure to the cap member 30 to discharge ink from the nozzle openings, and operating the suction pump 11 when the ink cartridge 8 is mounted to operate the ink from the recording head 7. And a suction control means 50 for discharging the ink, and performing a suction operation a plurality of times with a step of returning the pressure of the cap member 30 to the atmospheric pressure during the suction when the ink cartridge 8 is mounted. .

[0003]

The prior art will be described more specifically. FIGS. 17 and 18 show the structure of a conventional capping device. FIG. 17 is a sectional view showing a state in which the recording head 7 is sealed, and FIG. 18 shows an embodiment of the ink filling processing apparatus. In FIG. 17, a slider 20 is configured to move the upper surface of the base 21 in the horizontal and vertical directions following the movement of the carriage 1 when the carriage 1 moves to the non-printing area. The cap member 22 and the valve unit 36 are provided. Reference numeral 11 shown in FIG. 20 denotes a suction pump, which is formed with a through hole 32 communicating with the ink suction port 31 of the cap member 30 and also serves as a connection flow path with the suction pump 11. However, the filling mechanism in the conventional example is complicated and lacks reliability, and in addition to increasing the cost of parts, the volume of the maintenance mechanism for filling occupies about 1/4 of the image forming apparatus. Therefore, there is a problem that it is against the trend of miniaturization of equipment. In view of the above, the present invention aims to solve the problems of the related art, eliminates a suction pump and a valve unit as seen in a conventional ink jet head, and maintains the apparatus such as an initial filling. It is an object to provide an inkjet head having

[0004]

To achieve the above object, according to the present invention, a nozzle, a pressure chamber communicating with the nozzle, a fluid resistance portion communicating with a common liquid chamber, and a pressure chamber are provided. An image forming head, comprising: a provided vibration plate, and electrostatic driving means including an individual electrode opposed to the vibration plate, and performing recording by discharging the ink droplets from the nozzles by deforming the vibration plate. The main feature of the image forming head is that a diaphragm made of a thin plate is provided at the bottom of the common liquid chamber, and an electrode facing the diaphragm is provided. According to the second aspect, in the image forming head according to the first aspect, the electrode facing the diaphragm at the bottom of the common liquid chamber is mainly characterized by an image forming head formed of a PZT thin film. . According to claim 3, a nozzle, a pressure chamber communicating with the nozzle, a fluid resistance part communicating with the common liquid chamber, a diaphragm provided in the pressure chamber, and an individual electrode facing the diaphragm, And an electrostatic drive unit having a supply port for supplying ink to the common liquid chamber. In the image forming head for performing recording by discharging liquid from the nozzles by deforming the diaphragm, The most main features of the image forming head are a thin diaphragm provided at the bottom, an electrode facing the diaphragm, and a valve provided at the pressure chamber opening and the ink supply port of the fluid resistance part. According to the fourth aspect, in the image forming head according to the third aspect, the valve provided in the opening of the pressure chamber of the fluid resistance unit includes a groove provided in the opening of the pressure chamber of the fluid resistance unit, and a valve provided in the groove. The bulb provided at the ink supply port is formed by inserting a spherical member, and the tapered portion provided at the communication port to the common liquid chamber, and the spherical member is inserted into the tapered portion. The main feature is an image forming head. According to a fifth aspect of the present invention, in the image forming head according to the fourth aspect, a main feature of the image forming head is that the specific gravity of the spherical member substantially matches the specific gravity of the ink. According to the sixth aspect, in the image forming head according to the third aspect, the valve is an elastic member layer having a flap shape and a size capable of closing the pressure chamber opening and the ink supply port. The main feature is the forming head. According to a seventh aspect, in the image forming head according to the sixth aspect, the elastic member layer is mainly characterized in that the image forming head is formed of a dry film.

According to an eighth aspect of the present invention, in the image forming head according to the first aspect, a frequency applied between a vibration plate provided in the common liquid chamber and an electrode provided at a position facing the vibration plate. Is characterized mainly by an image forming head that matches a resonance frequency determined by the inertial mass of the common liquid chamber and the spring strength of the diaphragm. According to claim 9, claim 1
An image forming apparatus using the image forming head according to any one of the above items 1 to 8, is the most main feature. According to a tenth aspect of the present invention, in the ink filling method for filling the image forming head with the ink, a pulse voltage is first applied between the diaphragm provided in the common liquid chamber and the electrode provided at a position facing the diaphragm. And then applying a pulse voltage between a vibration plate provided in the pressure chamber at the time of the falling of the pulse and an electrode provided at a position facing the vibration plate to perform ink filling. The most main feature is an ink filling method for filling the ink. According to the eleventh aspect, in the method of manufacturing an image forming head, the PZT thin film formed on the thin diaphragm at the bottom of the common liquid chamber is in an aerosol state after mixing PZT fine particles in a gas. The most main feature is a method of manufacturing an image forming head in which fine particles of aerosol PZT are ejected from a nozzle to form a film on the diaphragm.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an example of an ink jet printer which is an image forming apparatus to which the present invention is applied. The carriage 1 is connected to a motor 3 by a timing belt 2, and is configured to be guided by a guide member 4 and move parallel to a platen (roller) 5. On the surface of the carriage 1 facing the recording paper 6, ink is supplied from a cartridge (not shown) via a supply pipe 7, and ink droplets are generated from nozzles by pressure generated when a diaphragm provided in a pressure chamber is displaced. Is provided with a recording head 100 that discharges ink. Reference numeral 8 denotes a capping device having a size capable of sealing a nozzle plate 101 of the recording head 100, which will be described later, in a single space. The ink is discharged from the nozzles by the action of a valve and a vibration plate which will be described later. As will be described in detail below with reference to FIG. 2, in the vicinity of the capping device 8, the recording head 100 is brought into contact with the nozzle plate 101 of the recording head 100 when the recording head 100 moves to the cleaning position in conjunction with the movement of the carriage 1. A cleaning device 11 including an elastic plate 10 made of a rubber or the like is provided. FIG. 2 shows the outer shape of the ink jet head 100 which is the recording head according to the present invention and the capping device 8. The inkjet head 100 includes a first substrate 110, a second substrate 120,
The third substrate 130 is joined, and a pipe 7 for supplying ink from an ink tank or cartridge (not shown), a guide 9, and flexible electrodes connected to individual electrodes and a common liquid chamber electrode described later. A wiring board 12 is provided.

FIG. 3 is a sectional view of the ink jet head 100. FIG. 4 is an exploded perspective view of the ink jet head 100. As is apparent from FIG. 3, the inkjet head 100 of the present embodiment is
It consists of a laminated structure in which three substrates are stacked and joined,
First substrate 110, third substrate 130, second substrate 12
0. In FIG. 3, the first substrate 1
Reference numeral 10 denotes a silicon substrate, and a plurality of nozzle communication holes 11
1 and a pressure chamber 113 connected to each other nozzle communication hole 111 and having a bottom wall as a diaphragm 112 is provided. The pressure chamber 113 includes a concave portion and a fluid resistance portion 114. Further, a common liquid chamber 115 composed of a concave portion for supplying ink is provided corresponding to each pressure chamber 113, and a diaphragm 116 is formed at the bottom of the common liquid chamber 115. Further, the insulating film 1 is provided below the diaphragms 112 and 116.
17 is formed. in this way,
The first gist of the present invention is that a diaphragm 116 is also formed at the bottom of a common liquid chamber 115 formed of a concave portion for supplying ink. The third substrate 130 is also a silicon substrate, which is directly bonded to the first substrate 110,
An individual electrode 131 having substantially the same shape as the vibration plate 112 formed on the insulating film 117 is arranged at a position facing the insulating film 117. The gap between the diaphragm 112 formed on the insulating film 117 and the individual electrode 131 on the third substrate 130 is about 0.3 μm. Further, a driving electrode 132 for driving the vibration plate 116 is provided at a position facing the vibration plate 116, and the vibration plate 116 formed on the insulating film 117 and the insulating film 117
Driving electrode 13 of common liquid chamber diaphragm 116 formed above
The gap with No. 2 is about 0.3 μm as described above.
Further, the flexible wiring board 12 connected to the individual electrode 131 and the driving electrode 132 is provided. The drive electrode 132 facing the diaphragm 116 at the bottom of the common liquid chamber 115 is formed of a PZT thin film. The second substrate 120 is made of borosilicate glass or the like, is adhered to the upper surface of the first substrate 110, and has the following configuration. That is, it is composed of an introduction groove 121 for supplying ink to the common liquid chamber 115, a pipe 7 for supplying ink from an ink tank or a cartridge, and a guide 9. After joining the three substrates, the nozzle plate 101,
The nozzle 102 and the nozzle communication hole 111 are aligned and bonded. The above three types of substrates are joined, and the image forming head 100 is completed. In FIG. 3, the provision of the valves 13 and 14 shown schematically is also the gist of the present invention, and this will be described later in detail.

FIG. 4 is an exploded perspective view of an ink jet head 100 as a recording head. The inkjet head 100 of the present invention includes three substrates 110, 120, and 13.
0 has a laminated structure in which the first substrate 110 is sandwiched with the first substrate 110 sandwiched therebetween, as described above. To facilitate understanding, the first substrate 110 shown in FIG.
Will be described again with reference to FIG. The first substrate 110 is a substrate made of silicon. In the substrate, a plurality of nozzle communication holes 111 and a bottom wall connected to each of the communication holes 111 are formed as recesses with pressure chambers 113 used as diaphragms 112. Have been Further, an insulating film 117 is provided below the diaphragm 112 (see FIG. 3). Further, a fluid resistance portion 114 is formed in the pressure chamber 113.
Further, there is a common liquid chamber 115 as a concave portion provided with a vibration plate 116 on the bottom wall for supplying ink in communication with each pressure chamber 113. Next, the description will proceed to the second substrate 130. A substrate 130 made of silicon like the first substrate 110 is directly bonded to the first substrate 110 by bonding or the like, and an individual electrode 131 having substantially the same shape is provided at a position facing the diaphragm 112. I have. The gap between the insulating film 117 formed below the diaphragm 112 and the individual electrode 131 on the second substrate 130 is about 0.3 μm. The individual electrode 131 has a lead portion 131a and a terminal portion 131b. Similarly, a drive electrode 132 having substantially the same shape is provided at a position facing the diaphragm 116, and has a lead portion 132a and a terminal portion 132b. The description now turns to the third substrate 120. A substrate 120 made of borosilicate glass or the like is adhered to the upper surface of the first substrate 110, and an introduction groove 121 for supplying ink to the common liquid chamber 115 and a pipe 7 for supplying ink from an ink tank or cartridge. And a guide 9 are provided. The above three types of substrates are joined, and the nozzle 1
02 is provided with the nozzle plate 101
The head 100 is completed by adhering after positioning and the nozzle communication hole 111. After the head assembly is completed, the first substrate 110 and the terminal portions 131a of the individual electrodes are provided.
2 and the drive electrode terminal 132b.
The driving circuit (not shown) is connected by the flexible wiring board 12 shown in FIG.

FIG. 5 shows the three substrates 110, 120,
FIG. 3 is a cross-sectional view of the head 100 to which the head 130 is joined, showing a first embodiment in which spherical movable members are used as the valves 13 and 14 described above. First substrate 110 and third substrate 12
The diaphragm 112, the diaphragm 112
, A pressure chamber 113 as a recess formed by the third substrate 120, a common liquid chamber 115 as a recess, and a pressure chamber 113.
Although the fluid resistance portion 114 between the and the common liquid chamber 115 exists as in FIG. 3, in FIG. 5, the spherical movable member 13a and the groove portion 15 for limiting the operation range of the spherical movable member 13a are provided. The difference is that they are formed. or,
5, a tapered portion 121a is formed in a communication hole 121 to a common liquid chamber 115 provided in a second substrate 120, and a valve made of a spherical movable member 14a is provided in the tapered portion 121a. Further, between the first substrate 110 and the substrate 130, an individual electrode 131 for exciting the diaphragm 112, a lead portion 131a, and a terminal 1 are provided.
31b is provided (see FIG. 4). On the front surface of the head 100, a nozzle plate 101 having a nozzle 102
Are arranged such that the nozzle 102 and the nozzle communication hole 111 are aligned. Reference numeral 16 denotes the ejected ink droplet. Next, the operation principle of the ink jet head 100 having the above-described configuration will be described with reference to FIG. 6 which is an enlarged view near the diaphragm 112 and FIG. 7 which is an applied pulse waveform diagram. After the head assembly is completed, the waveform pulse 45 shown in FIG. 7 is applied between the substrate 110 and the terminal 131b of the individual electrode.
Is applied. When the pulse 45 rises (see 40 in FIG. 7), an electrostatic force F acts between the individual electrode 131b and the diaphragm 112 of the substrate 110, and the diaphragm 112 in the initial state is in the suction state 112 ′. And is attracted to the individual electrode 131. Thereafter, when the pulse 45 falls (see 42 in FIG. 7), the diaphragm 112 moves to the position of the open state 112 ''. The pressure generated at this time causes the ink droplet 16 to be ejected from the meniscus formed in the nozzle 102.

Further, the injection efficiency improving technique of the present invention for reducing the driving voltage will be described with reference to FIG. FIG.
Based on the above, the propagation direction of the pressure generated in the ink liquid in the pressure chamber 113 due to the displacement of the vibration plate 112 is clarified. The propagation of pressure toward the nozzle 102 is indicated by an arrow Pf, and the propagation of pressure toward the fluid resistance portion 114 is indicated by an arrow Pb. Pressure chamber 11
3, among the propagations Pf and Pb of the pressure generated in
Is the pressure Pf generated in the direction of the nozzle of the pressure chamber 6. In the state shown in the figure, the arrow Pb, which is the propagation of pressure to the fluid resistance portion 114, collides with the fluid resistance portion 114 and only a part of the reflection pressure is applied to Pf. Exists in the pressure chamber, the arrow Pb, which is the propagation of pressure, collides with the spherical movable member 13a and is reflected, so that all the forces are applied to Pf, thereby improving the injection efficiency.

Next, with reference to FIGS. 8 and 7, the manner of discharging bubbles and filling ink will be described. In FIG. 8, the same pulse as described above is applied between the substrate 110 and the individual electrodes 131 and the common liquid chamber electrode 132. Then, the pressure chamber 113
The electrostatic force acts on both the vibration plate 112 and the vibration plate 116 of the common liquid chamber 115, and the volumes of the pressure chamber 113 and the common liquid chamber 115 increase as shown by the broken lines. Then, the common liquid chamber 1 is supplied from an ink cartridge (not shown) via a pipe 7.
The ink is drawn into the pressure chambers 15 and the pressure chamber 113, and then the electrostatic force disappears with the end of the pulse application, and the diaphragm 112 of the pressure chamber 113 and the diaphragm 1 of the common liquid chamber 115 are removed.
16 returns to the initial position by the respective elastic force. As a result, the sucked ink is pushed out toward the nozzle 102 to discharge bubbles and fill the ink. When the pulse is applied, the valve 14a moves in the direction of the common liquid chamber 115 similarly to the ink to replenish the ink, but when the pulse application is stopped, the ink is supplied to the common liquid chamber 11.
This blocks backflow from 5 to pipe 7. Therefore, the ejection power of the ink is not weakened. or,
As shown in FIG. 8, when the drive pulse 45 applied to the diaphragm 112 and the individual electrode 131 rises, the diaphragm 112 is attracted to the individual electrode 131. Therefore, the volume of the pressure chamber 113 increases, and the ink in the common liquid chamber 115 and the ink in the nozzle 102 flow into the pressure chamber 113. Many flow from the common liquid chamber 115. At this time, the spherical movable member 13
Fluid force Ff due to the generated flow acts on a. Due to this fluid force Ff, the spherical movable member 13a
It moves in two directions, the flow resistance of the fluid resistance part 114 decreases,
Ink will flow into the pressure chamber 113. Note that the specific gravity of the spherical movable members 13a and 14a is set to substantially the same value as that of the ink. Therefore, the operation is almost the same as that of the ink.
As a result, when the voltage is applied, the ink can flow in smoothly, while when the voltage is cut off, the ink moves in the same way as the ink flows, acting as a valve, and all the generated pressure is used for ejecting the ink. become. When the flat portion 41 of the drive pulse 45 is reached, the pressure chamber 11
Since the volume of No. 3 is constant, the inflow of ink is almost eliminated, and residual vibration due to inertial flow occurs. When the falling portion 42 of the drive pulse 45 comes, the diaphragm 112
The diaphragm 112 moves in a direction to reduce the volume of the pressure chamber 113 due to the restoring force of the diaphragm 112 because the electrostatic force F acting between the diaphragm 112 and the individual electrode 131 disappears. At this time, a pressure is generated, and the ink propagates in the directions of arrows Pf and Pb as shown in FIG. At the same time, a flow is generated in the pressure chamber 113. Due to this flow, a fluid force Ff acts on the spherical movable member 13a in the direction of the fluid resistance portion 114. As a result, the spherical movable member 13a moves toward the fluid resistance portion 114, and the fluid resistance portion 1
Fourteen openings are almost closed. Since the opening of the fluid resistance part 114 is substantially closed, the pressure Pb propagating in the direction of the fluid resistance part 114 is reflected by the fluid resistance part 114 and transmitted to the nozzle direction without transmitting to the common liquid chamber 115. The pressure becomes Pb ′, and the ink droplet 16 is ejected. Since the pressure escaping into the common liquid chamber 115 is small as described above, the energy for drop ejection increases as compared with the conventional example. After all, the ejection efficiency of the droplet ejection increases. Also, common liquid chamber 1
In the communication hole 121 to the nozzle 15, a taper portion 121 a is formed, and the valve made of the spherical movable member 14 a is provided in the taper portion 121 a, so that the diaphragm 116 is moved in a direction in which the volume of the common liquid chamber 115 decreases. Even if it works. The ink is blocked by the spherical movable member 14a and does not flow back.

Next, a second embodiment of the valves 13, 14 according to the present invention will be described with reference to FIG. In the first embodiment, the valves are spherical movable members 13a and 14a,
In the second embodiment, the pressure chamber 113 has a flap shape and
And an elastic member layer having a size capable of closing the opening and the ink supply port 121. As shown in FIG. 9, when the drive pulse 45 applied to the diaphragm 112 and the individual electrode 131 rises, the diaphragm 112 is attracted to the individual electrode 131 as shown by a broken line. Therefore, the volume of the pressure chamber 113 increases, and the flap-shaped member 13
b is deformed in the direction of the pressure chamber 113 by the force of the ink flowing through the groove 60 formed in the base 120, and
5 and the ink of the nozzle 102 flow into the pressure chamber 113. When the pressure pulse 113 falls to the initial position due to the fall of the drive pulse 45, the flap-shaped member 13b acts to block the flow of ink from the pressure chamber 113 to the common liquid chamber 115. Similarly, a flap-shaped member 14 b is present between the common liquid chamber 115 and the communication hole 121, and acts to block the flow from the common liquid chamber 115 to the communication hole 121. That is, it functions as a valve similarly to the above-mentioned spherical movable member. FIG. 10 shows an enlarged view of the flap 14b, which is one of the aforementioned flap-shaped members.
Since the flap member 14b is processed by photolithography into an elastic member layer made of a dry film, the flap member 14b operates stably with high shape accuracy. For example, it can be seen that the flap-shaped portion is pushed by the force of the ink flowing from the communication hole 121 and the ink flows. FIG. 11 shows a state in which the common liquid chamber 115 and the pressure chamber 113 are filled with ink.
4 shows a graph in which a diaphragm 116 of a common liquid chamber 115 is driven and its vibration amplitude is measured. From this graph, the diaphragm 11
It can be understood that, when driven at a resonance frequency f0 determined by the rigidity of No. 6 and the mass of ink in the common liquid chamber 115, the vibration displacement of the diaphragm 117 becomes extremely large. This is because the resonance state was established and the vibration amplitude increased. We decided to use such a frequency in the book head.

FIGS. 12 and 13 show that a pulse voltage is first applied between a vibration plate provided in the common liquid chamber and an electrode provided at a position facing the vibration plate. The embodiment of the third embodiment of the present invention in which ink is filled by applying a pulse voltage between a vibration plate provided in a pressure chamber and an electrode provided at a position facing the vibration plate has been described. When the driving signal shown in FIG. 14A is applied between the common liquid chamber diaphragm 116 and the electrode 132 shown in FIG. 12, the vibration plate 117 is deformed to the broken line by the electrostatic force, and the common liquid chamber 115 is formed. The volume of is expanded. Therefore, the ink is drawn into the common liquid chamber 115 via the flap member 14b. Since the flap member 14b plays a role of a valve for preventing backflow, ink does not flow back in the direction of the communication hole 121. In addition, the flap member 13b is also
Since the flow of ink from 3 to the common liquid chamber 115 is blocked, the ink is being drawn into the common liquid chamber 115. Next, in response to the fall of the pulse applied between the common liquid chamber diaphragm 117 and the electrode 130, FIG.
The pulse shown in (b) is applied between the pressure chamber diaphragm 112 and the individual electrode 131. Then, the common liquid chamber diaphragm 11
7 returns to the initial position, the volume of the common liquid chamber 115 decreases. On the other hand, since the pressure chamber diaphragm 112 moves to the position indicated by the broken line, the volume of the pressure chamber 113 expands, and the ink sucked into the common liquid chamber 115 increases. Is the substrate 12 by the force of the ink.
The fluid flows into the pressure chamber 113 via the groove 60 formed at 0 and the flap-shaped member 13b. By repeating this process, the ink is quickly filled.

Next, based on FIG. 15 and FIG.
A method for forming a ZT thin film will be described. In FIG. 15, a substrate 110 is set on a substrate holder 93 having a built-in heating stage 92 at an interval of several mm from the tip of the nozzle 91. Next, the vacuum pump 98 of the deposition chamber 94 is operated to open the mixing vessel gas introduction valve 95. Then, air is sucked into the mixing container 96, and the PZT fine particles soar up to form an aerosol. Nozzle 9 that has passed through conveyance pipe 97 due to a pressure difference
From 1, PZT fine particles are deposited by injecting the aerosolized PZT fine particles onto the substrate 110. By operating the substrate holder 93 in the illustrated XY directions, a PZT thin film of a desired size can be formed. FIG. 16 is a cross-sectional view showing a step of forming a common liquid chamber electrode 132 using the PZT thin film 18 formed on the substrate 110. First, a thickness of 0.3 μm on the substrate 110
A lower electrode 132c made of m Ti layers is formed. Next, a PZT thin film 18 is formed, and an upper electrode 132d made of a Ni layer is formed thereon.

[0015]

According to the first aspect of the present invention, the nozzle, the pressure chamber communicating with the nozzle, the fluid resistance portion communicating with the common liquid chamber, the diaphragm provided in the pressure chamber, and the diaphragm facing the diaphragm. An image forming head for performing recording by ejecting ink droplets from the nozzles by deforming the vibration plate and having an electrostatic driving means including a separate electrode formed on the bottom of the common liquid chamber; And an electrode opposed to the diaphragm, so that a filling mechanism is incorporated in the head for each color, so that a conventional suction pump or the like is not required, and the device can be downsized. In addition to the above, an image forming head capable of shortening the filling time can be provided.
According to the second aspect, in the image forming head according to the first aspect, the electrode facing the diaphragm at the bottom of the common liquid chamber is formed of a PZT thin film.
An image forming head capable of performing appropriate ink filling by the piezoelectric effect of the ZT thin film was provided. According to claim 3, a nozzle, a pressure chamber communicating with the nozzle, a fluid resistance part communicating with the common liquid chamber, a diaphragm provided in the pressure chamber, and an individual electrode facing the diaphragm, And an electrostatic drive unit having a supply port for supplying ink to the common liquid chamber. In the image forming head for performing recording by discharging liquid from the nozzles by deforming the diaphragm, A diaphragm made of a thin plate at the bottom and an electrode facing the diaphragm are provided, and a valve is provided at the pressure chamber opening and the ink supply port of the fluid resistance part, so that the backflow of ink can be prevented, An image forming head capable of extremely effective ink filling can be provided.
According to the fourth aspect, in the image forming head according to the third aspect, the valve provided in the opening of the pressure chamber of the fluid resistance unit includes a groove provided in the opening of the pressure chamber of the fluid resistance unit, and a valve provided in the groove. The bulb provided at the ink supply port is formed by inserting a spherical member, and the tapered portion provided at the communication port to the common liquid chamber, and the spherical member is inserted into the tapered portion. Therefore, it is possible to form a valve capable of preventing backflow of ink only by adding a spherical member, and to provide an image forming head capable of filling the ink with an extremely effective effect.

According to a fifth aspect of the present invention, in the image forming head according to the fourth aspect, the specific gravity of the spherical member substantially matches the specific gravity of the ink, so that the spherical member operates integrally with the ink. Thus, it was possible to provide an image forming head capable of obtaining a stable valve function. According to the sixth aspect, in the image forming head according to the third aspect, the valve is an elastic member layer having a flap shape and having a size capable of closing the pressure chamber opening and the ink supply port. As a result, a valve capable of preventing the backflow of ink can be formed, and an image forming head capable of filling the ink effectively can be provided. According to the seventh aspect, in the image forming head according to the sixth aspect, since the elastic member layer is formed of a dry film, the elastic member layer can operate stably with high accuracy in shape. An image forming head that can be provided. According to the eighth aspect, in the image forming head according to the first aspect, a frequency applied between the diaphragm provided in the common liquid chamber and an electrode provided at a position facing the diaphragm is common. Since the resonance frequency is determined by the inertial mass of the liquid chamber and the spring strength of the diaphragm, the amount of ink suctioned and discharged from the common liquid chamber diaphragm is maximized, and the ink filling property can be increased. An image forming head that can be provided. According to claim 9, any one of claims 1 to 8
Since the image forming apparatus uses the image forming head described in the section, it was possible to provide an image forming apparatus capable of achieving downsizing of the apparatus.

According to a tenth aspect of the present invention, in the ink filling method for filling the image forming head with the ink, the diaphragm provided first in the common liquid chamber and the electrode provided in a position facing the diaphragm are provided. Applying a pulse voltage between the vibration plate provided in the pressure chamber at the time of the falling of the pulse and an electrode provided at a position facing the vibration plate to perform ink filling. Therefore, the flow rate of the ink flowing from the common liquid chamber into the pressure chamber is increased, the discharge property of the bubbles remaining in the pressure chamber is improved, and the ink filling method for filling the image forming head with the ink can be improved. Could be provided. Claim 11
According to the method for manufacturing an image forming head, the PZT thin film formed on the diaphragm made of a thin plate at the bottom of the common liquid chamber is formed into an aerosol state after mixing PZT fine particles in a gas, and then the aerosol is formed. The PZT fine particles in the state are sprayed from the nozzle to form a film on the diaphragm, so that the film is formed at a high speed, and since the process is dry, the image is compatible with other processes. A method of manufacturing a forming head can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view of an ink jet printer which is an image forming apparatus to which the present invention is applied.

FIG. 2 is an outline drawing of an ink jet head which is a recording head according to the present invention.

FIG. 3 is a sectional view of an ink jet head which is a recording head according to the present invention.

FIG. 4 is an exploded perspective view of an ink jet head which is a recording head according to the present invention.

FIG. 5 is a sectional view of a first embodiment in which a spherical movable member is used as a valve in an ink jet head which is a recording head according to the present invention.

FIG. 6 is a diagram illustrating the improvement of the ink ejection efficiency of the present invention.

FIG. 7 is a pulse waveform diagram for driving the recording head according to the present invention.

FIG. 8 is an explanatory diagram illustrating a mode of discharging bubbles and filling ink with a recording head according to the present invention.

FIG. 9 is an explanatory diagram of a second embodiment in which a flap member is used as a valve in an ink jet head which is a recording head according to the present invention.

FIG. 10 is an enlarged view of a flap-shaped member of the present invention.

FIG. 11 is a diagram showing a graph in which a vibration plate of the common liquid chamber is driven and the vibration amplitude is measured while the common liquid chamber and the pressure chamber are filled with ink.

FIG. 12 is an explanatory view of a third embodiment of the present invention, showing a state in which a pulse voltage is applied between a diaphragm initially provided in the common liquid chamber and an electrode provided at a position facing the diaphragm. It is.

FIG. 13 is a diagram illustrating a third embodiment of the present invention in which ink is filled by applying a pulse voltage between a diaphragm provided in a pressure chamber and an electrode provided at a position facing the diaphragm at the time of falling of a pulse. It is explanatory drawing of an Example.

FIG. 14 is a pulse waveform diagram for driving a recording head according to a third embodiment of the present invention.

FIG. 15 is an explanatory view illustrating a method of forming a PZT thin film according to the present invention.

FIG. 16 is a sectional view illustrating an electrode formed by the method of forming a PZT thin film according to the present invention.

FIG. 17 is an explanatory diagram of an ink filling technique which is a conventional technique of the present invention.

FIG. 18 is a schematic diagram illustrating an ink filling technique as a conventional technique of the present invention.

[Explanation of symbols]

1 carriage, 2 timing belt, 3 motor,
4 Guide member, 5 Platen, 6 Recording paper, 7 Supply pipe, 8 Capping device, 9 Guide, 10
Elastic plate 11, 11 Cleaning device, 12 Flexible wiring board, 13 valve, 13a Spherical movable member, 13
b flap-shaped member, 14 valve, 14a spherical movable member, 14b flap-shaped member, 15 groove, 16
Injected ink droplet, 18 PZT thin film, 41 flat part, 42 falling part, 45 waveform pulse, 60
Groove, 91 nozzle, 92 heating stage, 93 substrate holder, 94 deposition chamber, 95 mixing vessel gas introduction valve, 96
Mixing container, 97 transport tube, 100 inkjet head, 101 nozzle plate, 102 nozzle, 11
0 first substrate, 111 nozzle communication hole, 112 diaphragm, 113 pressure chamber, 114 fluid resistance part, 115 common liquid chamber, 116 diaphragm, 117 insulating film, 120 second substrate, 121 introduction groove, 121a taper part , 1
30 third substrate, 131 individual electrode, 131a lead portion, 131b terminal portion, 132 drive electrode, 132
a lead part, 132b terminal part, 132c lower electrode,
132d upper electrode

Claims (11)

[Claims] A static chamber comprising a nozzle, a pressure chamber communicating with the nozzle, a fluid resistance part communicating with a common liquid chamber, a diaphragm provided in the pressure chamber, and an individual electrode facing the diaphragm. An image forming head having an electric driving means for deforming the diaphragm to eject ink droplets from the nozzles for recording, wherein a diaphragm made of a thin plate is provided at the bottom of the common liquid chamber, and the diaphragm is opposed to the diaphragm. An image forming head comprising: 2. The image forming head according to claim 1, wherein the electrode facing the diaphragm at the bottom of the common liquid chamber is P.
An image forming head formed of a ZT thin film. 3. A nozzle, a pressure chamber communicating with the nozzle, a fluid resistance part communicating with the common liquid chamber, a diaphragm provided in the pressure chamber, an individual electrode facing the diaphragm, and a common liquid. And an electrostatic drive unit having a supply port for supplying ink to the chamber, and by deforming the diaphragm, ejecting liquid from the nozzles to perform recording, the image forming head is provided at the bottom of the common liquid chamber. An image forming head comprising: a diaphragm made of a thin plate; an electrode facing the diaphragm; and a valve provided at a pressure chamber opening and an ink supply port of a fluid resistance portion. 4. The image forming head according to claim 3, wherein the valve provided at the opening of the pressure chamber of the fluid resistance portion is:
A groove formed in the pressure chamber opening of the fluid resistance section, and a spherical member inserted into the groove, and a valve provided in the ink supply port has a taper provided in a communication port to the common liquid chamber. And a spherical member inserted into the tapered portion. 5. The image forming head according to claim 4, wherein the specific gravity of the spherical member substantially matches the specific gravity of the ink. 6. The image forming head according to claim 3, wherein the valve is a flap-shaped elastic member layer having a size capable of closing the pressure chamber opening and the ink supply port. Image forming head. 7. The image forming head according to claim 6, wherein the elastic member layer is formed of a dry film. 8. The image forming head according to claim 1, wherein a frequency applied between the diaphragm provided in the common liquid chamber and an electrode provided at a position facing the diaphragm is a common liquid chamber. A resonance frequency determined by an inertial mass of the diaphragm and a spring strength of the diaphragm. 9. An image forming apparatus using the image forming head according to claim 1. Description: 10. An ink filling method for filling an image forming head with ink, wherein a pulse voltage is first applied between a vibration plate provided in a common liquid chamber and an electrode provided at a position facing the vibration plate. The image is characterized in that the ink is filled by applying a pulse voltage between a diaphragm provided in the pressure chamber at the time of the falling of the pulse and an electrode provided at a position facing the diaphragm. An ink filling method for filling a forming head with ink. 11. A method of manufacturing an image forming head, comprising: forming a PZT thin film on a diaphragm made of a thin plate at the bottom of a common liquid chamber after mixing fine particles of PZT in a gas;
PZT in aerosol state and then in aerosol state
Wherein the fine particles are sprayed from a nozzle to form a film on the vibrating plate.