JP2003025580A - Head chip unit and ink-jet recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a head chip unit and an ink-jet recorder which drive a head by a low voltage and have the ink discharge stability improved. SOLUTION: Chambers 17a-17c communicating with nozzle openings 25, and dummy chambers 18 where ink is not filled are alternately arranged side by side to a piezoelectric ceramic plate. Moreover, electrodes are set to side walls 19 at both sides of each of the chambers 17a-17c and dummy chambers 18. Electrodes in the chambers 17a-17c are made common electrodes 20a, and electrodes in the dummy chambers 18 are made discrete electrodes 20b. In the head chip unit for applying a driving electric field to the side walls 19 at both sides of each chamber 17a-17c, there is set a driving circuit which has a driving part for discrete electrodes which is connected to the discrete electrodes 20b to output a driving signal to each of the discrete electrodes 20b, and a driving part for common electrodes which is connected to the common electrodes 20a to output a driving signal to the common electrodes 20a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a head chip unit having an ink jet head applied to, for example, a printer, a fax machine, and an ink jet recording apparatus.

[0002]

2. Description of the Related Art Conventionally, a head unit having a recording head for ejecting ink from a plurality of nozzles is mounted,
2. Description of the Related Art Inkjet recording apparatuses that record characters and images on a recording medium are known. In such an ink jet recording apparatus, a head chip unit is provided in a head holder so that the recording head faces the recording medium to form an inkjet head, and the inkjet head is mounted on a carriage to convey the recording medium in a conveying direction. Is scanned in a direction orthogonal to.

FIG. 11 shows an exploded perspective view of an example of such a recording head, and FIG. 12 shows a cross section of a main part. As shown in FIGS. 11 and 12, the piezoelectric ceramic plate 101
A plurality of grooves 102 are provided side by side, and each groove 102 is separated by a side wall 103. One end of each groove 102 in the longitudinal direction extends to one end face of the piezoelectric ceramic plate 101, and the other end does not extend to the other end face, and the depth gradually decreases. Also, both side walls 1 in each groove 102
An electrode 105 for applying a driving electric field is formed on the opening-side surface of 03 along the longitudinal direction.

Grooves 102 of the piezoelectric ceramic plate 101
The cover plate 107 is joined to the opening side of the via an adhesive 109. In the cover plate 107, an ink chamber 111, which is a recess communicating with the shallower other end of each groove 102, and the groove 102 from the bottom of the ink chamber 111.
And an ink supply port 112 penetrating in the opposite direction.

Further, a nozzle plate 115 is joined to the end surface of the joined body of the piezoelectric ceramic plate 101 and the cover plate 107 where the groove 102 is open,
Nozzle openings 117 are formed in the nozzle plate 115 at positions facing the respective grooves 102.

The cover plate 107 is provided on the opposite side of the piezoelectric ceramic plate 101 from the nozzle plate 115.
A wiring board 120 is fixed to the surface opposite to the surface. A wiring 122 connected to each electrode 105 by a bonding wire 121 or the like is formed on the wiring board 120, and one end of the wiring 122 is provided in a drive circuit (not shown) equipped with a drive IC for driving the recording head. It is connected. Then, a drive voltage can be applied from the drive circuit to the electrode 105 via the wiring 122.

In the recording head thus constructed, ink is filled in each groove 102 from the ink supply port 112,
When a predetermined driving electric field is applied to the side walls 103 on both sides of the predetermined groove 102 via the electrode 105, the side wall 103 is deformed and the volume in the predetermined groove 102 is changed.
The ink in 02 is ejected from the nozzle opening 117.

For example, as shown in FIG. 13, the groove 102a
When ink is ejected from the nozzle opening 117 corresponding to, the positive drive voltage is applied to the electrodes 105a and 105b in the groove 102a and the electrodes 1 facing each other are applied.
05c and 105d are grounded. This allows
A driving electric field in the direction outward from the groove 102a acts on the side walls 103a and 103b, and if this is orthogonal to the polarization direction of the piezoelectric ceramic plate 101, the side walls 103a and 103b are deformed outward from the groove 102a by the piezoelectric thickness sliding effect. Then, the volume inside the groove 102a increases, and by returning it, the volume inside the groove 102a decreases and the pressure increases, and ink is ejected from the nozzle openings 117.

However, in a head chip unit equipped with such an ink jet head, when a conductive ink such as a water-based ink is used, the electrodes 105 facing each other in the groove 102 are electrically connected by the ink, so that normal driving is possible. There is a problem that you cannot do it.

For this reason, in an ink jet head using a conductive ink such as a water-based ink, there is only one groove used for ejecting ink, and the groove communicating with the nozzle opening for ejecting ink is used for the chamber and the ink ejecting. The groove that is not used and is not filled with ink is used as a dummy chamber. Then, the electrodes provided on the inner surfaces of both side walls of the chamber are used as common electrodes that have the same electric potential in all chambers, and the electrodes on the outer surfaces of both side walls of the chamber are used as individual electrodes that selectively drive the chambers. An electric field can be applied to the side walls of the ink and ink can be ejected from the chamber.

[0011]

However, in such an ink jet head for conductive ink, the conductive ink is ejected only by bending and deforming the side wall of the chamber outward in the width direction and returning it to the original position. Therefore, when ejecting ink at high speed or ejecting highly viscous ink, it is necessary to increase the deformation amount of the side wall at the time of ejection.
There is a problem that the meniscus is destroyed when the amount of deformation of the side wall is increased.

Further, in order to increase the amount of deformation of the side wall in this way, it is necessary to drive with a drive pulse of a large drive voltage, and there is a problem that the ejection stability is poor.

Furthermore, a method has also been proposed in which the drive voltage of the drive signal is driven by both power sources using positive and negative voltages, and the side wall is flexibly deformed in both the outer and inner directions with respect to the chamber to eject ink. However, in the case of driving with both of these power supplies, the peak value of the driving pulse can be small, but there is a problem that the driving circuit and the power supply circuit become complicated and the cost becomes high.

In view of such circumstances, it is an object of the present invention to provide a head chip unit and an ink jet recording apparatus which drive a head at a low voltage and improve ink ejection stability.

[0015]

According to a first aspect of the present invention for solving the above problems, a piezoelectric ceramic plate communicates with a nozzle opening, and a chamber filled with ink and a dummy chamber not filled with the ink are provided. Electrodes are provided on both side walls of each chamber and dummy chambers alternately arranged side by side, the electrodes in the chambers are used as common electrodes, and the electrodes in each dummy chamber are driven as individual electrodes on both side walls of each chamber. In a head chip unit that applies an electric field, a drive unit for an individual electrode that is connected to the individual electrode and outputs a drive signal to each individual electrode, and a common electrode that is connected to the common electrode and outputs a drive signal to the common electrode. And a drive circuit having a drive unit for use with the head chip unit.

According to a second aspect of the present invention, in the first aspect, the drive signal output from the individual electrode drive section and the common electrode drive section is given a positive or negative drive voltage. The head chip unit is characterized in that it is for

According to a third aspect of the present invention, in the first or second aspect, the drive signal output from the common electrode drive section continues to the application of the electric field to the side wall by the individual electrode drive section. In the head chip unit, the electric field in the opposite direction is applied.

In a fourth aspect of the present invention, in any one of the first to third aspects, the individual electrode corresponding to the side wall to which the electric field is not applied by the drive signal output from the common electrode drive section is In the head chip unit, the same drive signal as the drive signal output from the common electrode drive unit is simultaneously output from the individual electrode drive unit.

A fifth aspect of the present invention is the head chip unit according to any one of the first to fourth aspects, characterized in that the ink is a conductive ink.

According to a sixth aspect of the present invention, in any one of the first to fifth aspects, the common electrode drive section applied to the common electrode has either a rising or falling drive waveform up to a predetermined voltage. A head chip unit is characterized in that it includes a buffer circuit for controlling one or both times.

A seventh aspect of the present invention is an ink jet recording apparatus including the head chip unit according to any one of the first to sixth aspects.

According to the present invention, the deformation amount of the side wall can be increased with a low driving voltage, and the ink ejection characteristics can be improved.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below based on embodiments.

(Embodiment 1) FIG. 1 is an exploded perspective view of a head chip unit according to Embodiment 1, FIG. 2 is an exploded perspective view of a head chip, and FIG. 3 is a manufacturing process of a head chip unit. It is a perspective view which shows an example.

As shown in FIG. 1, the head chip unit 10 of this embodiment includes a head chip 11 and a base plate 12 provided on one side of the head chip 11.
A head cover 13 provided on the other surface side of the head chip 11, and a wiring board 30 on which a drive circuit 31 for driving the head chip 11 is mounted.

First, the head chip 11 will be described in detail. As shown in FIG. 2, in the piezoelectric ceramic plate 16 that constitutes the head chip 11, a chamber 17 that is a pressure chamber that communicates with the nozzle opening 25 and ejects ink.
And dummy chambers 18 not filled with ink are alternately arranged in parallel, and the chambers 17 and the dummy chambers 18 are
And are separated by a side wall 19.

One end portion in the longitudinal direction of each chamber 17 and the dummy chamber 18 is extended to one end surface of the piezoelectric ceramic plate 16, and the other end portion is not extended to the other end surface, and the depth gradually decreases. Has become.

Electrodes 20 for applying a driving electric field are formed on the surfaces of the openings of the chambers 17 and the dummy chambers 18 in the longitudinal direction.

Among the electrodes 20, the electrodes 20 provided on the inner surfaces of the side walls 19 on both sides of the chamber 17 are
When the ink inside is a conductive ink such as a water-based ink, the ink is conductive, so that the same potential is set in each chamber 17, and the wiring patterns described later in detail are connected so that all chambers 17 have the same potential. Common electrode 2
It is 0a.

Further, among the electrodes 20, a pair of electrodes 20 provided on the outer surface of the side walls 19 on both sides of the chamber 17 facing the common electrode 20a of each chamber 17, that is, in the dummy chamber 18, is provided for each chamber 17. The individual electrodes 20b can be provided with independent drive signals.

Further, the chamber 17 and the dummy chamber 18 formed in the piezoelectric ceramic plate 16 are formed by a disc-shaped die cutter, and the gradually decreasing depth is formed by using the shape of the die cutter. To be done. The electrodes 20 formed in the chambers 17 and the dummy chambers 18 are formed by, for example, known vapor deposition from an oblique direction.

Chamber 1 of piezoelectric ceramic plate 16
An ink chamber plate 21 is joined to the opening side of the dummy chamber 18 and the dummy chamber 18. The ink chamber plate 21 is an ink chamber 22 which is a recess communicating only with the shallower other end of each chamber 17, and an ink supply port 2 penetrating from the bottom of the ink chamber 22 in the opposite direction to the chamber 17.
3 and 3.

The ink chamber 22 of the ink chamber plate 21
Is communicated with only the other end of the chamber 17 which is shallow, and the dummy chamber 18 is not filled with the ink in the ink chamber 22 so that the individual electrodes 20b facing each other are not communicated with each other.

More specifically, a slit plate 38 having a slit 39 having a width equal to that of the chamber 17 is provided between the ink chamber plate 21 and the piezoelectric ceramic plate 16 at a position facing the chamber 17, and the slit plate 38 is used to form the chamber 17. And the ink chamber 22 are communicated with each other. With this slit plate 38, the dummy chamber 18
The inside is not filled with ink, so that the individual electrodes 20b in the dummy chamber 18 are not electrically connected to each other.

Here, in this embodiment, each chamber 17 is
Are divided into groups corresponding to the inks of black (B), yellow (Y), magenta (M), and cyan (C), and the ink chamber 22 and the ink supply port 23.
Are provided for each four.

The ink chamber plate 21 can be formed of a ceramic plate, a metal plate, or the like. However, considering the deformation after joining with the piezoelectric ceramic plate 16, a ceramic plate having a similar coefficient of thermal expansion is used. Is preferred.

A nozzle plate 24 is joined to the end surface of the bonded body of the piezoelectric ceramic plate 16 and the ink chamber plate 21 where the chamber 17 and the dummy chamber 18 are open, and each chamber 17 of the nozzle plate 24 is joined. A nozzle opening 25 is formed in a position facing the dummy chamber 18 by the nozzle plate 24.
Are sealed.

In this embodiment, the nozzle plate 24 is
It is larger than the area of the end face where the chamber 17 and the dummy chamber 18 of the joined body of the piezoelectric ceramic plate 16 and the ink chamber plate 21 are open. The nozzle plate 24 is formed by forming a nozzle opening 25 on a polyimide film or the like by using, for example, an excimer laser device. Further, although not shown, a water-repellent film having water repellency is provided on the surface of the nozzle plate 24 facing the printed material in order to prevent ink adhesion and the like.

In this embodiment, the nozzle support plate 26 is arranged around the end of the chamber 17 and the dummy chamber 18 of the joined body of the piezoelectric ceramic plate 16 and the ink chamber plate 21, which are open. There is. The nozzle support plate 26 is joined to the outside of the end face of the joined body of the nozzle plate 24 to stably hold the nozzle plate 24.

In the head chip 11 having such a structure, first, the piezoelectric ceramic plate 16 and the ink chamber plate 2
1 and 1 so as to sandwich the slit plate 38, and the nozzle plate 24 is joined to the end surface of the joined body. Then
It is formed by fitting and adhering the nozzle support plate 26 to the outer surface of the nozzle plate 24 and the bonded body of the piezoelectric ceramic plate 16 and the ink chamber plate 21.

The head chip unit 10 of this embodiment using such a head chip 11 will be described below.

As shown in FIGS. 1 and 3, in the head chip unit 10 of this embodiment, the individual electrode 20b is provided at the end of the piezoelectric ceramic plate 16 forming the head chip 11 on the side opposite to the nozzle opening 25 side. And the common electrode 20a
A wiring pattern (not shown) connected to the electrode 20 is formed, and a flexible cable 28 is joined to this wiring pattern via an anisotropic conductive film 27.

Further, the nozzle support plate 26 which is a joined body of the piezoelectric ceramic plate 16 and the ink chamber plate 21.
The base plate 12 made of aluminum on the piezoelectric ceramic plate 16 side and the ink chamber plate 2 are provided on the rear end side.
The head cover 13 on the first side is assembled. The base plate 12 and the head cover 13 are the base plate 1
The locking shaft 1 of the head cover 13 is fitted into the locking hole 12a of 2
It is fixed by engaging 3a, and the joined body of the piezoelectric ceramic plate 16 and the ink chamber plate 21 is sandwiched between them. The head cover 13 includes the ink chamber plate 2
An ink introduction path 29 communicating with each of the one ink supply ports 23 is provided.

Further, as shown in FIG. 3A, the wiring board 30 is fixed on the base plate 12 protruding to the rear end side of the piezoelectric ceramic plate 16. Here, a drive I for driving the head chip 11 is provided on the wiring board 30.
A drive circuit 31 having C is mounted, and the drive circuit 31 and the flexible cable 28 are connected via an anisotropic conductive film 32. As a result, the head chip unit 10 shown in FIG. 3B is completed.

Here, the wiring between the drive circuit 31 and the electrode 20 will be described. Note that FIG. 4 is a schematic diagram showing a connection state of wiring between the drive circuit and the head chip.

As shown in the figure, in the drive circuit 31, an external power source and an external signal such as a print signal are supplied to the external wiring 16.
It is input via 1. Specifically, the power supply and the external signal 160 are externally input to the drive circuit 31 by connecting the external wiring 161 to a wiring pattern provided on the wiring board 30 via an anisotropic conductive film or the like.

Further, the drive circuit 31 is provided with a plurality of terminals 33b from the individual electrode drive section and a terminal 33a from the common electrode drive section, and each terminal from the individual electrode drive section is provided. 33b are respectively connected to the pair of individual electrodes 20b of the chamber 17 via the flexible cable 28, and the terminals 33a from the common electrode driving section are connected to the common electrodes 20a of all the chambers 17 via the flexible cable 28. There is.

By connecting in this way, from the individual electrode drive section of the drive circuit 31 to each individual electrode 20b,
An independent drive signal is output for each chamber 17, and the same drive signal is output from the common electrode drive unit to all common electrodes 20a.

Here, the drive waveform output from the drive circuit 31 when ejecting or not ejecting ink droplets from each chamber 17 will be described in detail.

FIG. 5 is a sectional view of the piezoelectric ceramic plate and drive waveforms applied to the individual electrode and the common electrode.

Here, when the ink droplet is ejected from the chamber 17a, the drive waveform 1 applied to the common electrode 20a
Reference numeral 51 is a waveform in the region of drive waveforms B and E, which is the common electrode 20.
A positive drive voltage is applied to a. At this time, the drive waveform 150a is grounded. As a result, an electric field is applied to the side wall 19 and the side wall 19 is deformed outward with respect to the chamber 17a.

In this embodiment, the chambers 17a to 17c are used.
Drive waveforms 150a to 150 output to the individual electrodes 20b of
The c has a waveform that is continuous with the waveform of the B region or the E region of the drive waveform 151 in the C region or the F region. Thereby, the drive waveform 150a applied to the individual electrode 20b
17a to 17c driven by ˜150c
The opposite electric field is continuously applied to the side wall 19 of the side wall 19 and the side wall 19 is deformed toward the inside of the chambers 17a to 17c.

That is, according to the drive waveform shown in FIG.
When the two ink droplets are ejected from the chamber 17a in the C region and the F region, the voltage is applied to the common electrode 20a and the voltage is continuously applied to the individual electrodes 20b on both side walls of the chamber 17a. By the side wall 19
The ink droplets are ejected by being flexibly deformed outward with respect to the chamber 17 and then continuously flexibly deformed inward.

Since the drive signal for applying the voltage to the common electrode 20a is output in this way, in order to cancel the influence on the chambers 17b and 17c which do not eject ink, the individual electrodes corresponding to the chambers 17b and 17c which do not eject ink are cancelled. The waveform is output to the region 20b in the B region and the E region in synchronization with the signal output to the common electrode 20a. That is, in the present embodiment, the B region of the drive waveform 150b output to the individual electrode 20b of the chamber 17b,
With the E region of the drive waveform 150c output to the individual electrode 20b of the chamber 17c, the same waveforms as the C region and the F region of the drive waveform 151 applied to the common electrode 20a are applied.

Further, here, the drive waveform 15 shown in FIG.
FIG. 6 shows the movement of the side wall 19 when the ink droplets are ejected from the chamber 17a by 0a. 6 is a sectional view of the piezoelectric ceramic plate.

First, in the region A of the drive waveform 150a in FIG. 5, no voltage is applied to the individual electrode 20b and the common electrode 20a, and no electric field is applied to the side wall 19 as shown in FIG. Is not deformed and is in a drive waiting state.

Next, in the region B of the drive waveform 150a of FIG. 5, as shown in FIG. 6B, the drive voltage is applied to the common electrode 20a, so that the side walls 19a, 1a of the chamber 17a,
An electric field is applied to 9b, the side walls 19a and 19b are deformed so as to separate from each other outward, and the volume in the chamber 17a increases. At this time, ink is replenished from the ink chamber 22 into the chamber 17a.

Next, in the C region of the drive waveform 150a in FIG. 5, as shown in FIG. 6C, the drive voltage is not applied to the common electrode 20a, the common electrode 20a is grounded, and vice versa. By applying the drive voltage to the individual electrode 20b, an electric field opposite to that in FIG.
9a and 19b are deformed so as to approach each other inward from the state of FIG. 6 (b). As a result, the volume of the chamber 17a is reduced, the pressure inside the chamber 17a is increased, and ink droplets are ejected from the nozzle openings 25.

Then, in the D region of the drive waveform 150a of FIG. 5, no voltage is applied to the individual electrode 20b and the common electrode 20a, and the side wall 19 is in a drive waiting state in which it is not deformed. After that, in the E to G regions of the drive waveform 150a in FIG. 5, ink droplets are ejected again by repeating the same steps as those in the B to D regions of the drive waveform 150a described above.

In this way, by applying a voltage to the common electrode 20a with a driving waveform as shown in the figure, the deformation amount of the side wall 19 can be increased with a low voltage, and stable ink droplets can be ejected. Moreover, since the side wall 19 can be largely deformed even when the drive voltage applied to the individual electrode 20b and the common electrode 20a is low, the cost at the time of driving can be reduced.

(Second Embodiment) FIG. 7 is a circuit diagram and a drive waveform of a buffer circuit according to the second embodiment.

In the present embodiment, when the common electrode driving section of the drive circuit 31 applies a drive voltage to the common electrode 20a, a buffer circuit for controlling the time for applying the drive voltage up to a predetermined voltage is provided. The same as 1.

The buffer circuit 37 shown in the figure delays the time for applying the drive voltage up to a predetermined voltage when the drive voltage is applied by the common electrode drive section. More specifically, as shown in the figure, the common electrode drive section is provided. This is to gently change the rising and falling curves of the drive waveform of.

The drive waveform from the common electrode drive section is input from a of the buffer circuit 37, the rising of the drive waveform is delayed in b by the buffer circuit 37, and the drive waveform of the drive waveform input from a is input in c. Fall is delayed.

At d, a drive waveform obtained by combining the drive waveforms of b and c of the buffer circuit 37, that is, a drive waveform in which the rising and falling edges are delayed, is given to the common electrode 20a.

The side wall 19 is formed by using such a driving waveform of d.
Is deformed, the side wall 19 is gradually deformed inward with respect to the chamber 17 in a predetermined time, and further gradually deformed to the original state in a predetermined time.

By providing the buffer circuit 37 in the individual electrode drive section, it is not necessary to provide the buffer circuit 37 for each individual electrode 20b, and the time for rising to a predetermined voltage or the time for falling from a predetermined voltage is controlled. be able to. This makes it possible to easily control the movement of each side wall 19 in accordance with the characteristics such as ink viscosity and the ink ejection environment to eject a clean ink droplet. Also,
Ink ejection characteristics can be improved to improve print quality, and the manufacturing can be performed at low cost.

In this embodiment, the buffer circuit 37 for delaying both the rising time and the falling time of the drive waveform from the common electrode drive section is provided, but the present invention is not limited to this, and for example, ink Depending on the characteristics,
Either the rising or the falling of the driving waveform may be delayed.

Further, in the present embodiment, the buffer circuit 3
Although 7 is separately provided, the present invention is not limited to this, and for example, it may be incorporated in the drive circuit 31 of the first embodiment and used.

(Other Embodiments) Above, Embodiments 1 and 2
However, the present invention is not limited to such a configuration.

In the drive circuit having the individual electrode drive section and the common electrode drive section of the above-described first and second embodiments, the drive circuit mounted in the conventional head chip unit or the like for ejecting the insulating ink is diverted. Therefore, the manufacturing cost can be reduced.

Here, an example of the drive circuit is shown in FIG. Note that FIG. 8 is a schematic diagram showing an example of the drive circuit.

As shown in the figure, the drive circuit 31A comprises an individual electrode drive section 34 which is a drive circuit mounted on a conventional head chip unit, and a common electrode drive section 35 which is separately provided.

The individual electrode driving section 34 has a plurality of terminals 36, and any one of the terminals 36 among the plurality of terminals 36.
The terminals 36b other than a are connected to the individual electrodes 20b, and output a drive signal from the individual electrode drive unit 34 to the individual electrodes 20b.

Further, one terminal 36a of the plurality of terminals 36 is connected to the common electrode drive section 35, and the output side of the common electrode drive section 35 is connected to the common electrode 20a. According to this individual electrode drive unit 34, the terminal 36
The drive waveform for the common electrode 20a output from b is a drive waveform whose timing is shifted so that an electric field opposite to the electric field applied to the side wall 19 by the common electrode drive unit 35 is continuously applied to the side wall 19. can do.

Further, in the above-described first embodiment, the chamber 17 and the dummy chamber 18 are formed as grooves having the same depth, but the present invention is not limited to this. For example, the depth of the dummy chamber may be deeper than that of the chamber. May be.

The head chip unit 10 as described above is
The head unit 70 is formed by being assembled to the tank holder that holds the ink cartridge.

An example of this tank holder is shown in FIG. The tank holder 60 shown in FIG. 9 has a substantially box-like shape with one surface open, and is capable of holding an ink cartridge detachably. Further, on the upper surface of the bottom wall, there is provided a connecting portion 61 which is connected to an ink supply port which is an opening formed at the bottom of the ink cartridge. The connecting portion 61 is provided for each color ink of black (B), yellow (Y), magenta (M), and cyan (C), for example. An ink flow path (not shown) is formed in the communication part 61, and the filter 6 is provided at the tip of the connection part 61 which is an opening thereof.
Two are provided. In addition, the ink flow path formed in the connecting portion 61 is formed so as to communicate with the back surface side of the bottom wall, and each ink flow path is not shown in the flow path substrate 63 provided on the back surface side of the tank holder 60. It communicates with a head connection port 64 that opens to the side wall of the flow path substrate 63 via the ink flow path. The head connection port 64 is opened to the side surface side of the tank holder 60, and the head chip unit holding portion 65 for holding the above-described head chip unit 10 is provided at the bottom portion of the side wall. The head chip unit holding portion 65 includes a surrounding wall 66 that stands up in a substantially U-shape that surrounds the drive circuit 31 provided on the wiring board 30, and a base plate 12 of the head chip unit 10 that is inside the surrounding wall 66. An engagement shaft 67 that engages with the locking hole 30a provided in the wiring board 30 is provided upright.

Therefore, the head chip unit 10 is mounted on the head chip unit holding portion 65 to complete the head unit 70. At this time, the ink introducing path 29 formed in the head cover 13 is connected to the head connecting port 64 of the flow path substrate 63. As a result, the ink introduced from the ink cartridge through the connecting portion 61 of the tank holder 60 is introduced into the ink introduction passage 29 of the head chip unit 10 through the ink passage in the passage substrate 63, and the ink chamber 22 And the chamber 17 is filled.

The head unit 70 thus formed is used by being mounted on the carriage of an ink jet recording apparatus, for example. An outline of an example of this usage mode is shown in FIG.

As shown in FIG. 10, the carriage 71 is
A pulley 74a, which is mounted on the pair of guide rails 72a and 72b so as to be movable in the axial direction, is provided on one end side of the guide rail 72 and is connected to the carriage drive motor 73, and a pulley provided on the other end side. It is conveyed via a timing belt 75 which is hung around 74b. On both sides of the carriage 71 in the direction orthogonal to the transport direction, a pair of transport rollers 76 and 77 are provided along the guide rails 72a and 72b, respectively. These transport rollers 76 and 77 are provided below the carriage 71 in a direction orthogonal to the transport direction of the carriage 71, and the recording medium S.
Is to be transported.

The head unit 70 described above is mounted on the carriage 71, and the ink cartridge described above can be removably attached to the head unit 70.

According to such an ink jet recording apparatus, the head chip records characters and images on the recording medium S by scanning the recording medium S and scanning the carriage 71 in a direction orthogonal to the feeding direction. can do.

[0084]

As described above, according to the present invention, by inputting the drive signal to the individual electrode and the drive signal to the common electrode, the deformation amount of the side wall can be increased at a low drive voltage. In addition, it is possible to reduce the cost at the time of driving and improve the ink ejection characteristics by ejecting clean ink droplets.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a head chip unit according to a first embodiment of the present invention.

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

FIG. 3 is a perspective view showing an assembly process of the head chip unit according to the first embodiment of the present invention.

FIG. 4 is a schematic view showing the wiring connection between the drive circuit and the head chip according to the first embodiment of the present invention.

5A and 5B are a sectional view and a drive waveform diagram of the piezoelectric ceramic plate according to the first embodiment of the present invention.

FIG. 6 is a cross-sectional view showing a modified example of the side wall of the head chip according to the first embodiment of the invention.

FIG. 7 is a diagram showing drive waveforms of a buffer circuit and various parts thereof according to a second embodiment of the present invention.

FIG. 8 is a diagram showing another example of a drive circuit according to another embodiment of the present invention.

FIG. 9 is a perspective view showing an assembly process of a head unit according to another embodiment of the present invention.

FIG. 10 is a schematic perspective view of an ink jet recording apparatus according to another embodiment of the present invention.

FIG. 11 is a schematic perspective view showing an outline of a head chip according to a conventional technique.

FIG. 12 is a cross-sectional view showing an outline of a head chip according to a conventional technique.

FIG. 13 is a cross-sectional view showing an outline of a head chip according to a conventional technique.

[Explanation of symbols]

Reference Signs List 10 head chip unit 11 head chip 12 base plate 13 head cover 16 piezoelectric ceramic plates 17, 17a, 17b, 17c chamber 18 dummy chambers 19, 19a, 19b side wall 20 electrode 20a common electrode 20b individual electrode 24 nozzle plate 30 wiring board 31 drive circuit 33a , 33b terminal 34 individual electrode drive section 35 common electrode drive section 36, 36a, 36b terminal 37 buffer circuit 38 slit plate 60 tank holder 70 head units 150a to 150c, 151, 152a to 152c, 1
53 Drive waveform 160 Power supply and external signal 161 External wiring

Claims (7)

[Claims] 1. A piezoelectric ceramic plate is communicated with a nozzle opening, chambers filled with ink and dummy chambers not filled with ink are alternately arranged in parallel, and electrodes are provided on each side wall of each chamber and the dummy chamber. In a head chip unit that is provided with the electrodes in the chamber as a common electrode and the electrodes in each dummy chamber as individual electrodes to apply a driving electric field to the sidewalls on both sides of each chamber, A head chip comprising a drive circuit having an individual electrode drive unit for outputting a drive signal to an electrode and a common electrode drive unit connected to the common electrode for outputting a drive signal to the common electrode. unit. 2. The drive signal output from the individual electrode drive section and the common electrode drive section is for applying either positive or negative drive voltage. The head chip unit according to 1. 3. The drive signal output from the common electrode drive unit is for applying an electric field in the opposite direction continuously to the application of the electric field to the side wall by the individual electrode drive unit. The head chip unit according to claim 1 or 2. 4. The same drive signal output from the common electrode drive unit is applied to the individual electrodes corresponding to the sidewalls to which no electric field is applied by the drive signal output from the common electrode drive unit. The head chip unit according to claim 1, wherein the individual electrode driving units simultaneously output. 5. The head chip unit according to claim 1, wherein the ink is a conductive ink. 6. The common electrode drive section to be applied to the common electrode includes a buffer circuit for controlling a rising time or a falling time of a driving waveform to a predetermined voltage or both of them. The head chip unit according to any one of claims 1 to 5. 7. An ink jet recording apparatus comprising the head chip unit according to claim 1.