Patent Description:
Inkjet printers and inkjet plotters that utilize an inkjet recording method are known as printing apparatuses. A liquid droplet discharge head for discharging liquid is mounted in printing apparatuses utilizing such an inkjet method.

A piezoelectric method is one of liquid droplet discharge methods of such a liquid droplet discharge head. A liquid droplet discharge head employing the piezoelectric method has a structure in which a flexible substrate is extracted outward through a slit portion of a reservoir that supplies liquid. The slit portion is directly connected to an electrode portion to which the flexible substrate and a piezoelectric actuator substrate are electrically connected. Patent Document <NUM> discloses a liquid discharge head according to the preamble of claim <NUM>. Patent Document <NUM> discloses a liquid jetting head including: a channel forming substrate having a pressure chamber communicating with a nozzle, and provided with a piezoelectric element for generating pressure in the pressure chamber; and a wiring board driving the piezoelectric element, wherein a mount section is connected to the wiring board with an ACP in an insertion hole. Inside the insertion hole, a first filler is filled to cover the mount section connected to the wiring board, and second filler is filled on the upper side of the first filler.

The present invention provides a liquid droplet discharge head according to claim <NUM>, a liquid droplet discharge head according to claim <NUM>, and a recording device according to claim <NUM>.

Embodiments of a liquid droplet discharge head and a recording device disclosed in the present application will be described in detail below with reference to the accompanying drawings. Note that the invention according to the present application is not limited to the embodiments that will be described below.

A piezoelectric method is one of the methods for discharging liquid from a liquid discharge head. A liquid droplet discharge head employing the piezoelectric method has a structure in which a flexible substrate is extracted outward through a slit portion of a reservoir that supplies liquid. The slit portion is directly connected to an electrode portion to which the flexible substrate and a piezoelectric actuator substrate are electrically connected.

In order to protect the electrode portion, resin may be applied to the slit portion so as to seal the slit portion. In that case; however, not only a considerable amount of resin is required to seal the entire slit portion, but also unsolidified resin may flow into the electrode portion to cause an operation failure. Besides, there is no way to confirm whether or not the slit portion is completely sealed.

Therefore, in view of these problems, the method of sealing the slit portion described above is expected to be improved.

First, an overview of a printer <NUM> which is an example of a recording device according to an embodiment will be described with reference to <FIG> and <FIG>. <FIG> is a schematic front view of a printer <NUM> according to the embodiment. <FIG> is a schematic plan view of a printer <NUM> according to the embodiment.

As illustrated in <FIG>, the printer <NUM> includes a paper feed roller <NUM>, guide rollers <NUM>, an applicator <NUM>, a head case <NUM>, a plurality of conveying rollers <NUM>, a plurality of frames <NUM>, a plurality of liquid discharge heads <NUM>, conveying rollers <NUM>, a dryer <NUM>, conveying rollers <NUM>, a sensor <NUM>, and a collection roller <NUM>.

The printer <NUM> further includes a controller <NUM> that controls each part of the printer <NUM>. The controller <NUM> controls operations of the paper feed roller <NUM>, the guide rollers <NUM>, the applicator <NUM>, the head case <NUM>, the plurality of conveying rollers <NUM>, the plurality of frames <NUM>, the plurality of liquid discharge heads <NUM>, the conveying rollers <NUM>, the dryer <NUM>, the conveying rollers <NUM>, the sensor unit <NUM>, and the collection roller <NUM>.

By landing droplets on the printing sheet P, the printer <NUM> records images and characters on the printing sheet P. Before use, the printing sheet P is wound around the paper feed roller <NUM> and ready to be extracted. The printer <NUM> conveys the printing sheet P from the paper feed roller <NUM> to the inside of the head case <NUM> via the guide rollers <NUM> and the applicator <NUM>.

The applicator <NUM> uniformly applies a coating agent over the printing sheet P. With surface treatment thus performed on the printing sheet P, the printing quality of the printer <NUM> can be improved.

The head case <NUM> houses the plurality of conveying rollers <NUM>, the plurality of frames <NUM>, and the plurality of liquid discharge heads <NUM>. The inside of the head case <NUM> is formed with a space separated from the outside except for a part connected to the outside such as parts where the printing sheet P enters and exits.

If necessary, the controller <NUM> controls at least one of controllable factors of the internal space of the head case <NUM>, such as temperature, humidity, and barometric pressure. The conveying rollers <NUM> convey the printing sheet P to the vicinity of the liquid discharge heads <NUM>, inside the head case <NUM>.

The frames <NUM> are rectangular flat plates, and are positioned above and close to the printing sheet P conveyed by the conveying rollers <NUM>. As illustrated in <FIG>, a plurality of (for example, four) frames <NUM> are provided inside the head case <NUM> such that the longitudinal direction of the frames <NUM> is orthogonal to the conveyance direction of the printing sheet P. Each of the plurality of frames <NUM> is disposed at a predetermined interval along the conveyance direction of the printing sheet P.

In the following description, the conveyance direction of the printing sheet P is also referred to as a "sub scanning direction," and a direction orthogonal to the sub scanning direction and parallel to the printing sheet P is also referred to as a "main scanning direction".

Liquid, for example, ink, is supplied to the liquid discharge heads <NUM> from a liquid tank (not illustrated). Each liquid discharge head <NUM> discharges the liquid supplied from the liquid tank.

The controller <NUM> controls the liquid discharge heads <NUM> based on data of an image, characters, and the like to discharge the liquid toward the printing sheet P. The distance between each liquid discharge head <NUM> and the printing sheet P is, for example, approximately <NUM> to approximately <NUM>.

The liquid discharge heads <NUM> are fixed to the frame <NUM>. For example, the liquid discharge heads <NUM> are fixed to the frame <NUM> at both end portions in the longitudinal direction. The liquid discharge heads <NUM> are fixed to the frame <NUM> such that the longitudinal direction of the liquid discharge heads <NUM> are parallel to the main scanning direction.

That is, the printer <NUM> according to the embodiment is a so-called line printer in which the liquid discharge heads <NUM> are fixed inside the printer <NUM>. Note that the printer <NUM> according to the embodiment is not limited to a line printer and may also be a so-called serial printer.

A serial printer is a printer employing a method of alternately performing operations of recording while moving the liquid discharge heads <NUM> in a manner such as reciprocation in a direction intersecting (for example, substantially orthogonal to) the conveyance direction of the printing sheet P, and conveying the printing sheet P.

As illustrated in <FIG>, a plurality of (for example, five) liquid discharge heads <NUM> are provided in one frame <NUM>. <FIG> illustrates an example in which two liquid discharge heads <NUM> are disposed on the front side and three liquid discharge heads <NUM> are disposed on the rear side in the sub scanning direction, in such a manner that the centers of the respective liquid discharge heads <NUM> do not overlap with each other in the sub scanning direction.

The plurality of liquid discharge heads <NUM> disposed in one frame <NUM> form a head group 8A. Four head groups 8A are positioned along the sub scanning direction. The liquid discharge heads <NUM> belonging to the same head group 8A are supplied with ink of the same color. As a result, the printer <NUM> can perform printing with four colors of ink using the four head groups 8A.

The colors of the ink discharged from the respective head groups 8A are, for example, magenta (M), yellow (Y), cyan (C), and black (K). The controller <NUM> can print a color image on the printing sheet P by controlling each of the head groups 8A to discharge the plurality of colors of ink onto the printing sheet P.

Note that a surface treatment may be performed on the printing sheet P, by discharging a coating agent from the liquid discharge heads <NUM> onto the printing sheet P.

Furthermore, the number of the liquid discharge heads <NUM> included in one head group 8A and the number of the head groups 8A provided in the printer <NUM> can be changed as appropriate in accordance with printing targets and printing conditions. For example, if the color to be printed on the printing sheet P is a single color and the range of the printing can be covered by a single liquid discharge head <NUM>, only a single liquid discharge head <NUM> may be provided in the printer <NUM>.

The printing sheet P thus subjected to the printing process inside the head case <NUM> is conveyed by the conveying rollers <NUM> to the outside of the head case <NUM>, and passes through the inside of the dryer <NUM>. The dryer <NUM> dries the printing sheet P after the printing process. The printing sheet P thus dried by the dryer <NUM> is conveyed by the conveying rollers <NUM> and then collected by the collection roller <NUM>.

In the printer <NUM>, by drying the printing sheet P with the dryer <NUM>, it is possible to suppress bonding between the printing sheets P rolled while being overlapped with each other, and rubbing between undried liquid at the collection roller <NUM>.

The sensor <NUM> includes a position sensor, a speed sensor, a temperature sensor, and the like. Based on information from the sensor <NUM>, the controller <NUM> can determine the state of each part of the printer <NUM> and control each part of the printer <NUM>.

In the printer <NUM> described above, the printing sheet P is a printing target (that is, a recording medium), but a printing target in the printer <NUM> is not limited to the printing sheet P, and a roll type fabric or the like may be a printing target.

In addition, instead of directly conveying the printing sheet P, the printer <NUM> may have a configuration in which the printing sheet P is put on a conveyor belt and conveyed. By using the conveyor belt, the printer <NUM> can perform printing on a sheet of paper, a cut cloth, wood, a tile, or the like as a printing target.

Further, the printer <NUM> described above may discharge a liquid containing electrically conductive particles from the liquid discharge heads <NUM>, to print a wiring pattern or the like of an electronic device.

Furthermore, the printer <NUM> described above may discharge a liquid containing a predetermined amount of liquid chemical agent or liquid containing the chemical agent from the liquid discharge heads <NUM> onto a reaction vessel or the like to produce chemicals.

The printer <NUM> described above may also include a cleaner for cleaning the liquid discharge heads <NUM>. The cleaner cleans the liquid discharge heads <NUM> by, for example, a wiping process or a capping process.

The wiping process is, for example, a process of using a flexible wiper to rub a second surface 21b (see <FIG>) of a channel member <NUM> (see <FIG>), which is an example of a surface of a portion from which a liquid is discharged, thereby removing the liquid attached to the second surface 21b.

The capping process is, for example, a process of removing clogging of discharge holes <NUM> (see <FIG>) by covering a portion from which a liquid is discharged with a cap, and repeating the discharging of the liquid. This process is performed as described below. First, a cap is provided so as to cover the second surface 21b of the channel member <NUM> which is an example of the portion from which the liquid is discharged (this action is referred to as capping). This action forms a substantially sealed space between the second surface 21b and the cap. The discharge of liquid is then repeated in such a sealed space. This can remove a liquid having a viscosity higher than that in the normal state, foreign matter, or the like that has clogged a discharge hole <NUM>.

A configuration of the liquid discharge head <NUM> according to the embodiment will be described with reference to <FIG> is an exploded perspective view illustrating a schematic configuration of the liquid discharge head <NUM> according to the embodiment.

The liquid discharge head <NUM> includes a head body <NUM>, a wiring portion <NUM>, a housing <NUM>, and a pair of heat dissipation plates <NUM>. The head body <NUM> includes the channel member <NUM>, a piezoelectric actuator substrate <NUM> (see <FIG>), and a reservoir <NUM>.

In the following description, for the purpose of convenience, a direction in which the head body <NUM> is provided in the liquid discharge head <NUM> may be referred to as "downward," and a direction in which the housing <NUM> is provided relative to the head body <NUM> may be referred to as "upward".

The channel member <NUM> of the head body <NUM> has a substantially flat plate shape, and includes a first surface 21a (see <FIG>), which is one main surface, and the second surface 21b (see <FIG>) located at an opposite side from the first surface 21a. The first surface 21a has an opening 61a (see <FIG>), and a liquid is supplied into the channel member <NUM> from the reservoir <NUM> through the opening 61a.

A plurality of discharge holes <NUM> (see <FIG>) used to discharge the liquid onto the printing sheet P are provided on the second surface 21b. A channel through which a liquid flows from the first surface 21a to the second surface 21b is formed inside the channel member <NUM>.

The piezoelectric actuator substrate <NUM> is located on the first surface 21a of the channel member <NUM>. The piezoelectric actuator substrate <NUM> includes a plurality of displacement elements <NUM> (see <FIG>). In addition, a flexible substrate <NUM> of the wiring portion <NUM> is electrically connected to the piezoelectric actuator substrate <NUM>.

The reservoir <NUM> is disposed on the piezoelectric actuator substrate <NUM>. The reservoir <NUM> includes an opening 23a at both end portions thereof in the main scanning direction. The reservoir <NUM> has a channel therein, and is supplied with a liquid from the outside through the opening 23a. The reservoir <NUM> has a function of supplying the liquid to the channel member <NUM> and a function of storing the liquid to be supplied.

The wiring portion <NUM> includes the flexible substrate <NUM>, a wiring board <NUM>, a plurality of driver ICs <NUM>, a pressing member <NUM>, and an elastic member <NUM>. The flexible substrate <NUM> has a function of transferring a predetermined signal sent from the outside to the head body <NUM>. Note that, as illustrated in <FIG>, the liquid discharge head <NUM> according to the embodiment includes two flexible substrates <NUM>.

One end portion of the flexible substrate <NUM> is electrically connected to the piezoelectric actuator substrate <NUM> of the head body <NUM>. The other end portion of the flexible substrate <NUM> is extracted upward so as to be inserted into a slit portion 23b of the reservoir <NUM>, and is electrically connected to the wiring board <NUM>. This enables the piezoelectric actuator substrate <NUM> of the head body <NUM> and the outside to be electrically connected.

The wiring board <NUM> is located above the head body <NUM>. The wiring board <NUM> has a function of distributing a signal to the plurality of driver ICs <NUM>.

The plurality of driver ICs <NUM> are provided on one main surface of the flexible substrate <NUM>. As illustrated in <FIG>, in the liquid discharge head <NUM> according to the embodiment, two driver ICs <NUM> are provided on one flexible substrate <NUM>, but the number of driver ICs <NUM> provided on one flexible substrate <NUM> is not limited to two.

The driver IC <NUM> drives the piezoelectric actuator substrate <NUM> of the head body <NUM> on the basis of a signal transmitted from the controller <NUM> (see <FIG>). With this configuration, the driver IC <NUM> drives the liquid discharge head <NUM>.

The pressing member <NUM> is substantially U-shaped in a cross-sectional view, and is configured to press the driver IC <NUM> on the flexible substrate <NUM> toward the heat dissipation plate <NUM> from the inner side. With this configuration, the embodiment enables heat generated when the driver IC <NUM> drives to be efficiently dissipated to the heat dissipation plate <NUM> on the outer side.

The elastic member <NUM> is provided so as to be in contact with an outer wall of a pressing portion (not illustrated) of the pressing member <NUM>. By providing the elastic member <NUM>, it is possible to reduce the likelihood of the pressing member <NUM> damaging the flexible substrate <NUM> at the time when the pressing member <NUM> presses the driver IC <NUM>.

The elastic member <NUM> is made of, for example, double-sided foam tape or the like. In addition, for example, by using a non-silicon-based thermal conductive sheet for the elastic member <NUM>, it is possible to improve the heat dissipating property of the driver IC <NUM>. Note that the elastic member <NUM> does not necessarily have to be provided.

The housing <NUM> is disposed on the head body <NUM> so as to cover the wiring portion <NUM>. This enables the wiring portion <NUM> to be sealed with the housing <NUM>. The housing <NUM> is made of, for example, a resin or a metal or the like.

The housing <NUM> has a box shape extending in the main scanning direction, and includes a first opening 40a and a second opening 40b on a pair of side surfaces opposed to each other along the main scanning direction. In addition, the housing <NUM> includes a third opening 40c at a lower surface, and includes a fourth opening 40d at an upper surface.

One of the heat dissipation plates <NUM> is disposed on the first opening 40a so as to close the first opening 40a. The other of the heat dissipation plates <NUM> is disposed on the second opening 40b so as to close the second opening 40b.

The heat dissipation plates <NUM> are provided so as to extend in the main scanning direction, and are made of a metal, an alloy, or the like having a high heat dissipating property. The heat dissipation plates <NUM> are provided so as to be in contact with the driver ICs <NUM>, and have a function of dissipating heat generated by the driver ICs <NUM>.

The pair of heat dissipation plates <NUM> are fixed to the housing <NUM> respectively with screws not illustrated. Thus, the housing <NUM> to which the heat dissipation plates <NUM> are fixed has a box shape in which the first opening 40a and the second opening 40b are closed and the third opening 40c and the fourth opening 40d are open.

The third opening 40c is provided so as to be opposed to the reservoir <NUM>. The flexible substrate <NUM> and the pressing member <NUM> are inserted into the third opening 40c.

The fourth opening 40d is provided in order to insert a connector (not illustrated) provided on the wiring board <NUM>. It is preferable that a portion between the connector and the fourth opening 40d be sealed using resin or the like. This makes it possible to suppress entry of a liquid, dust, or the like into the housing <NUM>.

Furthermore, the housing <NUM> includes thermal insulation portions 40e. The thermal insulation portions 40e are provided so as to be adjacent to the first opening 40a and the second opening 40b, and are provided so as to protrude outward from side surfaces of the housing <NUM> along the main scanning direction.

In addition, the thermal insulation portions 40e are formed so as to extend in the main scanning direction. That is, the thermal insulation portions 40e are located between the heat dissipation plates <NUM> and the head body <NUM>. By providing the housing <NUM> with the thermal insulation portions 40e in this manner, it is possible to suppress transfer of heat generated by the driver ICs <NUM> through the heat dissipation plates <NUM> to the head body <NUM>.

Note that, <FIG> illustrates an example of the configuration of the liquid discharge head <NUM>, and the liquid discharge head <NUM> may further include components other than those illustrated in <FIG>.

A configuration of the head body <NUM> according to the embodiment will be described with reference to <FIG>. <FIG> is an enlarged plan view of the head body <NUM> according to the embodiment. <FIG> is an enlarged view of a region surrounded by a dot-dash line illustrated in <FIG>. <FIG> is a cross-sectional view taken along the line VI-VI illustrated in <FIG>.

As illustrated in <FIG>, the head body <NUM> includes the channel member <NUM> and the piezoelectric actuator substrate <NUM>. The channel member <NUM> includes a supply manifold <NUM>, a plurality of pressurizing chambers <NUM>, and a plurality of discharge holes <NUM>.

The plurality of pressurizing chambers <NUM> are connected to the supply manifold <NUM>. The plurality of discharge holes <NUM> are each connected to corresponding one of the plurality of pressurizing chambers <NUM>.

Each of the pressurizing chambers <NUM> opens to the first surface 21a (see <FIG>) of the channel member <NUM>. Furthermore, the first surface 21a of the channel member <NUM> has an opening 61a that communicates with the supply manifold <NUM>. In addition, a liquid is supplied from the reservoir <NUM> (see <FIG>) through the opening 61a to the inside of the channel member <NUM>.

In the example illustrated in <FIG>, the head body <NUM> has four supply manifolds <NUM> located inside the channel member <NUM>. Each of the supply manifolds <NUM> has a long thin shape extending along the longitudinal direction (that is, in the main scanning direction) of the channel member <NUM>. At both ends of the supply manifold <NUM>, the opening 61a of the supply manifold <NUM> is formed on the first surface 21a of the channel member <NUM>.

In the channel member <NUM>, a plurality of pressurizing chambers <NUM> are formed so as to expand two-dimensionally. As illustrated in <FIG>, each of the pressurizing chambers <NUM> is a hollow region having a substantially diamond planar shape with corner portions being rounded. The pressurizing chamber <NUM> opens to the first surface 21a of the channel member <NUM>, and is closed by the piezoelectric actuator substrate <NUM> being bonded to the first surface 21a.

The pressurizing chambers <NUM> form a pressurizing chamber row arrayed in the longitudinal direction. The pressurizing chambers <NUM> in two adjacent pressurizing chamber rows are arranged in a staggered manner between the two pressurizing chamber rows. In addition, one pressurizing chamber group includes four pressurizing chamber rows connected to one supply manifold <NUM>. In the example illustrated in <FIG>, the channel member <NUM> includes four pressurizing chamber groups.

Furthermore, relative arrangements of the pressurizing chambers <NUM> within individual pressurizing chamber groups are configured in the same manner, and the pressurizing chamber groups are arranged in a manner such that they are slightly shifted from each other in the longitudinal direction.

The discharge holes <NUM> are disposed at positions of the channel member <NUM> other than a region that is opposed to the supply manifold <NUM>. That is, the discharge holes <NUM> do not overlap with the supply manifold <NUM> in a transparent view of the channel member <NUM> from the first surface 21a side.

Furthermore, in a plan view, the discharge holes <NUM> are disposed within a region in which the piezoelectric actuator substrate <NUM> is mounted. One group of such discharge holes <NUM> occupies a region having approximately the same size and shape as the piezoelectric actuator substrate <NUM>.

Then, the displacement element <NUM> (see <FIG>) of a corresponding piezoelectric actuator substrate <NUM> is caused to be displaced, thereby discharging droplets from the discharge hole <NUM>.

As illustrated in <FIG>, the channel member <NUM> has a layered structure in which a plurality of plates are layered. These plates include a cavity plate 21A, a base plate 21B, an aperture plate 21C, a supply plate 21D, manifold plates 21E, 21F, and <NUM>, a cover plate <NUM>, and a nozzle plate 21I arranged in this order from the upper surface of the channel member <NUM>.

A large number of holes are formed in these plates. The thickness of each of the plates is approximately <NUM> to approximately <NUM>. With this configuration, the holes can be formed with high accuracy. The individual plates are layered while aligned with respect to each other such that these holes communicate with each other to form a predetermined channel.

In the channel member <NUM>, the supply manifold <NUM> and the discharge hole <NUM> communicate through an individual channel <NUM>. The supply manifold <NUM> is located on the second surface 21b side within the channel member <NUM>, and the discharge hole <NUM> is located at the second surface 21b of the channel member <NUM>.

The individual channel <NUM> includes a pressurizing chamber <NUM> and an individual supply channel <NUM>. The pressurizing chamber <NUM> is located at the first surface 21a of the channel member <NUM>. The individual supply channel <NUM> serves as a channel that connects the supply manifold <NUM> and the pressurizing chamber <NUM>.

In addition, the individual supply channel <NUM> includes a reduction portion <NUM> having a width narrower than other portions. The reduction portion <NUM> has a width narrower than other portions of the individual supply channel <NUM>, and hence, has a high channel resistance. In this manner, when the channel resistance of the reduction portion <NUM> is high, pressure occurring at the pressurizing chamber <NUM> is less likely to escape to the supply manifold <NUM>.

The piezoelectric actuator substrate <NUM> includes piezoelectric ceramic layers 22A and 22B, a common electrode <NUM>, an individual electrode <NUM>, a connecting electrode <NUM>, a dummy connecting electrode <NUM>, and a front surface electrode <NUM> (see <FIG>).

The piezoelectric actuator substrate <NUM> has the piezoelectric ceramic layer 22A, the common electrode <NUM>, the piezoelectric ceramic layer 22B, and the individual electrode <NUM> layered in this order.

Both of the piezoelectric ceramic layers 22A and 22B each extend over the first surface 21a of the channel member <NUM> so as to extend across the plurality of pressurizing chambers <NUM>. The piezoelectric ceramic layers 22A and 22B each have a thickness of approximately <NUM>. For example, the piezoelectric ceramic layers 22A and 22B are made of a lead zirconate titanate (PZT)-based ceramic material having ferroelectricity.

The common electrode <NUM> is formed over substantially the entire surface in a surface direction of a region between the piezoelectric ceramic layer 22A and the piezoelectric ceramic layer 22B. That is, the common electrode <NUM> overlaps with all the pressurizing chambers <NUM> in the region that is opposed to the piezoelectric actuator substrate <NUM>.

The thickness of the common electrode <NUM> is approximately <NUM>. For example, the common electrode <NUM> is made of a metal material such as an Ag-Pd based material.

The individual electrode <NUM> includes a body electrode 72a and an extraction electrode 72b. The body electrode 72a is located in a region of the piezoelectric ceramic layer 22B that is opposed to the pressurizing chamber <NUM>. The body electrode 72a is slightly smaller than the pressurizing chamber <NUM>, and has a shape substantially similar to that of the pressurizing chamber <NUM>.

The extraction electrode 72b is extracted out from the body electrode 72a to be outside the region that is opposed to the pressurizing chamber <NUM>. The individual electrode <NUM> is made of, for example, a metal material such as an Au-based material.

The connecting electrode <NUM> is located on the extraction electrode 72b, and is formed to have a convex shape with a thickness of approximately <NUM>. The connecting electrode <NUM> is electrically connected to an electrode provided on the flexible substrate <NUM> (see <FIG>). The connecting electrode <NUM> is made of, for example, silver-palladium, including glass frit.

The dummy connecting electrode <NUM> is located on the piezoelectric ceramic layer 22B and is positioned so as not to overlap with various electrodes such as the individual electrode <NUM>. The dummy connecting electrode <NUM> connects the piezoelectric actuator substrate <NUM> and the flexible substrate <NUM> to increase the connection strength.

Furthermore, the dummy connecting electrode <NUM> makes uniform distribution of the contact positions between the piezoelectric actuator substrate <NUM> and the piezoelectric actuator substrate <NUM>, and stabilizes the electrical connection. The dummy connecting electrode <NUM> is preferably made of a material equivalent to that of the connecting electrode <NUM>, and is preferably formed in a process equivalent to that of the connecting electrode <NUM>.

The front surface electrode <NUM> illustrated in <FIG> is formed on the piezoelectric ceramic layer 22B and at a position that does not interfere with the individual electrode <NUM>. The front surface electrode <NUM> is connected to the common electrode <NUM> through a via hole formed in the piezoelectric ceramic layer 22B.

With this configuration, the front surface electrode <NUM> is grounded and maintained at the ground electric potential. The front surface electrode <NUM> is preferably made of a material equivalent to that of the individual electrode <NUM>, and is preferably formed in a process equivalent to that of the individual electrode <NUM>.

A plurality of individual electrodes <NUM> are individually electrically connected to the controller <NUM> (see <FIG>) via the flexible substrate <NUM> and wiring, in order to individually control the electric potential of each individual electrode <NUM>. By setting the individual electrode <NUM> and the common electrode <NUM> to have different electric potentials, and applying an electric field in the polarization direction of the piezoelectric ceramic layers 22A, the portion of the piezoelectric ceramic layer 22A to which the electric field is applied operates as an activation section distorted due to a piezoelectric effect.

In other words, in the piezoelectric actuator substrate <NUM>, portions of the individual electrode <NUM>, the piezoelectric ceramic layer 22A, and the common electrode <NUM> that are opposed to the pressurizing chamber <NUM> function as the displacement element <NUM>.

In addition, unimorph deformation of the displacement element <NUM> results in the pressurizing chamber <NUM> being pressed and a liquid being discharged from the discharge hole <NUM>.

Next, a procedure of driving the liquid discharge head <NUM> according to the embodiment will be described. The individual electrode <NUM> is set to be at a higher electric potential (hereinafter, also referred to as a "high electric potential") than the common electrode <NUM> in advance. Then, each time a discharge request is made, the individual electrode <NUM> is once set to be the same electric potential (hereinafter, referred as a "low electric potential") as the common electrode <NUM>, and then is again set at the high electric potential at a predetermined timing.

With this configuration, at the timing when the individual electrode <NUM> changes to the low electric potential, the piezoelectric ceramic layers 22A and 22B return to their original shapes, and the volume of the pressurizing chamber <NUM> increases to be higher than the initial state, that is, higher than the state of the high electric potential.

At this time, negative pressure is applied to the inside of the pressurizing chamber <NUM>. Thus, a liquid in the supply manifold <NUM> is sucked into the interior of the pressurizing chamber <NUM>.

After this, the piezoelectric ceramic layers 22A and 22B deform so as to protrude toward the pressurizing chamber <NUM> at the timing when the individual electrode <NUM> is again set to the high electric potential.

In other words, the inside of the pressurizing chamber <NUM> has a positive pressure as a result of a reduction in the volume of the pressurizing chamber <NUM>. Thus, the pressure of the liquid within the pressurizing chamber <NUM> rises, and droplets are discharged from the discharge hole <NUM>.

In other words, in order to discharge droplets from the discharge hole <NUM>, the controller <NUM> supplies a drive signal including pulses based on the high electric potential to the individual electrode <NUM> using the driver IC <NUM>. It is only necessary to set the pulse width to an acoustic length (AL) that is a length of time for a pressure wave to propagate from the reduction portion <NUM> to the discharge hole <NUM>.

With this configuration, when the inside of the pressurizing chamber <NUM> changes from the negative pressure state to the positive pressure state, the pressures under both of the states are combined, which makes it possible to discharge the droplets with higher pressure.

In addition, in a case of gray scale printing, the gray scale is expressed based on the number of droplets continuously discharged from the discharge hole <NUM>, that is, the amount (volume) of droplets adjusted based on the number of times the droplets are discharged. Thus, the droplets are discharged a number of times corresponding to the designated gray scale to be expressed, through the discharge hole <NUM> corresponding to the designated dot region.

In general, when the liquid discharge is continuously performed, an interval between the pulses that are supplied to discharge the droplets may be set to the AL. Due to this, a period of a residual pressure wave of pressure generated in discharging the droplets discharged earlier matches a period of a pressure wave of pressure to be generated in discharging droplets to be discharged later.

Thus, the residual pressure wave and the pressure wave are superimposed, whereby the droplets can be discharged with a higher pressure. Note that in this case, the speed of the droplets to be discharged later is increased, and the impact points of the plurality of droplets become close.

Details of the reservoir <NUM> according to the embodiment will be described with reference to <FIG>. <FIG> and <FIG> are perspective views illustrating an outer appearance configuration of the reservoir <NUM> according to the embodiment. <FIG> is a cross-sectional view taken along the line IX-IX illustrated in <FIG>. <FIG> is a perspective view illustrating an outer appearance configuration in which the closing member <NUM> is disposed on the reservoir <NUM> according to the embodiment.

As illustrated in <FIG>, the reservoir <NUM> includes a pair of slit portions 23b provided along the longitudinal direction of the reservoir <NUM>. The slit portion 23b is a groove-like gap having a substantially square cross-sectional shape. The slit portion 23b opens in a substantially square planar shape in the upper surface of the reservoir <NUM>, and communicates between the outside of the reservoir <NUM> and a hollow inner region 23c (see <FIG>) formed inside the reservoir <NUM>. For example, the slit portion 23b can be formed by drilling the reservoir <NUM> vertically along the thickness direction of the reservoir <NUM> by means of cutting or the like, or can be formed by molding integrally with the reservoir <NUM> using a predetermined mold form or the like prepared in advance.

<FIG> illustrates an example in which a plurality of slit portions 23b are provided in the reservoir <NUM>, but the configuration is not particularly limited to this example. Further, <FIG> illustrates an example of the shape of the slit portion 23b provided in the reservoir <NUM>, and the shape of the slit portion 23b is not particularly limited to the example illustrated in <FIG>, and can be appropriately changed as necessary.

As illustrated in <FIG>, the flexible substrate <NUM> extracted upward from the inside of the reservoir <NUM> is inserted into the slit portion 23b. Further, as illustrated in <FIG>, the slit portion 23b is directly connected to an electrode portion <NUM> that is a region to which the flexible substrate <NUM> and the piezoelectric actuator substrate <NUM> are electrically connected.

As illustrated in <FIG>, in the reservoir <NUM> including the slit portion 23b as illustrated in <FIG>, a closing member <NUM> is disposed in the slit portion 23b so as to close the slit portion 23b. Then, in the reservoir <NUM>, the closing member <NUM> is disposed in the slit portion 23b and a sealing resin (not illustrated) is disposed on the closing member <NUM>.

A disposed state of the closing member <NUM> according to the embodiment will be described with reference to <FIG>. <FIG> and <FIG> are perspective views illustrating an outer appearance configuration of the closing member <NUM> according to the embodiment. <FIG> is a cross-sectional view taken along the line XIII-XIII illustrated in <FIG>. <FIG> is a cross-sectional view taken along the line XIV-XIV illustrated in <FIG>. <FIG> is an explanatory diagram for checking a sealed condition according to the embodiment. <FIG> is a diagram illustrating an example of a component layout according to the embodiment.

As illustrated in <FIG>, the closing member <NUM> includes a pair of legs <NUM> and <NUM> opposed to each other along the longitudinal direction. As illustrated in <FIG>, the legs <NUM> and <NUM> are portions to be inserted into the slit portions 23b, and configured with dimensions with which the legs <NUM> and <NUM> can close the whole gaps in the slit portions 23b and can be inserted into the slit portions 23b. The legs <NUM> and <NUM> function as portions respectively located in the slit portions 23b.

As illustrated in <FIG>, the closing member <NUM> includes a connecting portion <NUM> bridging between one end portions of the legs <NUM> and <NUM>, and a connecting portion <NUM> bridging between the other end portions of the legs <NUM> and <NUM> along the width direction perpendicular to the longitudinal direction.

As described above, the closing member <NUM> has a structure in which the legs <NUM> and <NUM> to be inserted into the slit portions 23b and the connecting portions <NUM> and <NUM> connecting the legs <NUM> and <NUM> are provided in accordance with the number, the shape, and the size of the slit portions 23b. The structure of the closing member <NUM> facilitates processing at the time of manufacturing.

A lower surface <NUM> of the connecting portion <NUM> illustrated in <FIG> and a lower surface <NUM> of the connecting portion <NUM> illustrated in <FIG> come into contact with an upper surface 23TS of the reservoir <NUM> when the respective legs <NUM> and <NUM> are fully inserted into the slit portions 23b. This stabilizes the posture of the closing member <NUM> disposed in the slit portions 23b.

Further, as illustrated in <FIG> and <FIG>, after the closing member <NUM> is disposed in the slit portions 23b, the reservoir <NUM> is sealed by applying a resin (a sealing resin) <NUM> to the slit portions 23b. As described above, according to the embodiment, since the closing member <NUM> is disposed in the slit portions 23b, the amount of a resin used for sealing the slit portions 23b can be reduced as compared with the case where the entire slit portions 23b are sealed with the resin <NUM>.

In addition, by using the closing member <NUM> that can be easily disposed in the slit portions 23b, the tact time of the process for sealing the slit portions 23b can be shortened as compared with the case where the entire slit portions 23b are sealed with the resin <NUM> from the beginning.

In addition, the upper surface 101a of the leg <NUM> illustrated in <FIG> has a smooth convex structure raised in an arc shape in a vertically upward direction. Similarly, the upper surface 102a of the leg <NUM> illustrated in <FIG> also has a smooth convex structure raised in an arc shape in a vertically upward direction. This makes it easy to seal the slit portions 23b with the resin <NUM>.

On the other hand, the lower surface 101b of the leg <NUM> illustrated in <FIG> has a smooth convex structure raised in an arc shape in a vertically downward direction in a cross-sectional view. Similarly, the lower surface 102b of the leg <NUM> illustrated in <FIG> also has a smooth convex structure raised downward in an arc shape. This facilitates insertion of the closing member <NUM> into the slit portions 23b. The convex structure of the legs <NUM> and <NUM> functions as a trap that prevents the resin <NUM> from flowing into the electrode portion <NUM> in a case where the resin <NUM> applied to the slit portions 23b leaks from the gap between the closing member <NUM> and the slit portions 23b into the inner region 23c of the reservoir <NUM> (see <FIG>). That is, the resin <NUM> leaked from the gap between the closing member <NUM> and the slit portions 23b easily moves along the surfaces of the smooth convex structure of the legs <NUM> and <NUM>. This can increase the probability that the resin <NUM> will be solidified before flowing into the electrode portion <NUM>.

Further, by disposing the closing member <NUM> in the slit portions 23b before sealing the slit portions 23b with the resin <NUM>, the unsolidified resin <NUM> can be prevented from flowing into the electrode portion <NUM> (see <FIG>), and thus avoiding the occurrence of malfunction.

Incidentally, the closing member <NUM> is configured such that, when the closing member <NUM> is disposed in the slit portions 23b, the upper surface 101a of the leg <NUM> and the upper surface 102a of the leg <NUM> are lower than the upper surface 23TS of the reservoir <NUM> (see <FIG>). This makes it easy to apply the resin <NUM> so as not to protrude from the slit portions 23b.

In addition, for example, the resin <NUM> can be applied to the slit portions 23b in such a manner that an upper surface 200TS of the resin <NUM> is lower than the upper surface 23TS (the top surface) of the reservoir <NUM> as in illustrated in <FIG>. This allows the upper surface 23TS (the top surface) of the reservoir <NUM> to be used as a region where various components are disposed. For example, when a liquid tank <NUM> is provided in the reservoir <NUM> as illustrated in <FIG>, a region where a heater <NUM> for controlling the temperature of a liquid is disposed can be secured on the upper surface 23TS (the top surface) of the reservoir <NUM>.

The flexible substrate <NUM> is extracted outward from the outer side of the closing member <NUM> disposed in the slit portion 23b (see <FIG> and <FIG>). That is, the flexible substrate <NUM> is temporarily fixed by the closing member <NUM>, and thereby the movement of the flexible substrate <NUM> can be restrained. This makes it possible to prevent excessive stress from being applied to the electrode portion <NUM> that is a region to which the flexible substrate <NUM> and the piezoelectric actuator substrate <NUM> are electrically connected, by the movement of the flexible substrate <NUM>.

As illustrated in <FIG>, a channel 104a and a channel outlet 104b are provided in the lower surface <NUM> of the connecting portion <NUM>. As illustrated in <FIG>, the channel 104a communicates between the channel outlet 104b and the inner region 23c of the slit portions 23b in a state where the closing member <NUM> is disposed in the slit portions 23b. The channel outlet 104b is provided near the center of the connecting portion <NUM> in the width direction.

As described above, by providing the channel 104a and the channel outlet 104b in the closing member <NUM>, whether the slit portions 23b are completely sealed can be checked. For example, after the closing member <NUM> is disposed in the slit portions 23b and the slit portions 23b are sealed with the resin <NUM>, air can be injected from the channel outlet 104b as illustrated in <FIG> in order to check whether the slit portions 23b are completely sealed.

In addition, since the channel outlet 104b is provided near the center of the connecting portion <NUM> in the width direction, checking of the sealed condition can be easily performed. Further, when the lower surface <NUM> of the connecting portion <NUM> comes into contact with the upper surface 23TS of the reservoir <NUM>, the connecting portion <NUM> and the lower surface <NUM> can increase the sealing performance with respect to the upper surface 23TS of the reservoir <NUM>.

Furthermore, the sealability of the slit portions 23b can be increased by sealing the channel outlet 104b with the resin <NUM> after the checking of the sealed condition.

<FIG> illustrates an example in which a plurality of slit portions 23b are provided in the reservoir <NUM>, but the configuration is not particularly limited to this example. Further, the shape of the slit portion 23b illustrated in <FIG> is not particularly limited to the example illustrated in <FIG>, and can be appropriately changed as necessary.

The embodiment disclosed by the present application can be modified without departing from the main point or the scope of the present invention. In addition, the embodiment disclosed by the present application can be combined as appropriate. For example, the embodiment described above can be modified in the following manner.

<FIG> is a cross-sectional view according to a modified example. As illustrated in <FIG>, resin sealing may be performed in such a manner that, with the flexible substrate <NUM> extracted outward from the slit portion 23b (see <FIG>, <FIG>, and <FIG>), the closing member <NUM> is disposed in the slit portion 23b, and then the resin <NUM> is applied to the outside and the inside of the flexible substrate <NUM>.

Alternatively, the shape of the closing member <NUM> described in the above embodiment may be changed as described below. <FIG> is a perspective view illustrating an outer appearance configuration in a state where a closing member according to a modified example is disposed.

As illustrated in <FIG>, a closing member <NUM> according to a modified example is disposed in each of a pair of slit portions 23b of the reservoir <NUM> so as to close the slit portions 23b. The closing member <NUM> has a rod shape along the shape of the slit portion 23b. <FIG> is a side view of a closing member according to a modified example. <FIG> is a perspective view of an outer appearance of a closing member according to a modified example as viewed from above. <FIG> is a partially enlarged view illustrating an end portion of a closing member according to a modified example. <FIG> is a partially enlarged view of a cross-section taken along the line XXII-XXII illustrated in <FIG>. In the following description, unless it is necessary to particularly distinguish between substantially the same portions, such portions will be described without particular distinction, only by assigning the same reference signs, for example, a claw ST_400, a notch NT_400, and a top surface SF_400.

As illustrated in <FIG>, the closing member <NUM> includes a convex structure portion HBP_400 having a substantially semicircular cross-section raised in an upward direction in the longitudinal direction of the closing member <NUM>. This facilitates resin sealing after the closing member <NUM> is disposed in the slit portion 23b. In addition, since the slit portion 23b is easily filled with a resin, the rigidity of the slit portion 23b can be expected to be increased.

Further, as illustrated in <FIG>, a claw ST1_400 is provided at one end portion of the closing member <NUM>, and a claw ST2_400 is provided at the other end portion of the closing member <NUM>. The closing member <NUM> is supported at a predetermined position by the claws ST_400 being caught on the top surface 23TS of the reservoir 23b at the both end portions of the slit portion 23b in the longitudinal direction instead of being buried in the slit portion 23b. By providing the claws ST_400, the closing member <NUM> can be prevented from being buried in the slit portion 23b. Meanwhile, the closing member <NUM> can be positioned at an appropriate position.

Further, as illustrated in <FIG>, a notch NT1_400 continuous from the claw ST1_400 is provided at one end portion of the closing member <NUM>, and a notch NT2_400 continuous from the claw ST2_400 is provided at the other end portion of the closing member <NUM>. By providing the notches NT_400, a sealing resin can spread around the closing member <NUM>.

As illustrated in <FIG> or <FIG>, the closing member <NUM> has a structure in which the position of a top surface SF1400 of a connecting portion connecting the claw ST1_400 and a convex structure portion HBP_400 is lower than the top surfaces of the claw ST1400 and the convex structure portion HBP_400 in the cross-sectional direction of the closing member <NUM>. Similarly, the height of a top surface SF2_400 of a portion connecting the claw ST2_400 and the convex structure portion HBP400 is lower than the claw ST2_400 and the convex structure portion HBP_400.

Claim 1:
A liquid droplet discharge head (<NUM>) comprising
a reservoir (<NUM>) comprising a slit portion (23b) through which a flexible substrate (<NUM>) is extracted outward, wherein
a closing member (<NUM>, <NUM>) is disposed in the slit portion (23b), and
a sealing resin (<NUM>) is disposed on the closing member (<NUM>, <NUM>),
characterized in that the closing member (<NUM>) has a rod shape along a shape of the slit portion (23b) and comprises a convex structure portion (HBP_400) having a substantially semicircular cross-section raised upward in a longitudinal direction of the closing member (<NUM>, <NUM>).