1. Field of the Invention
The present invention relates to a head chip, a liquid jet head, a liquid jet recording device, and a method of manufacturing the head chip.
2. Description of the Related Art
In recent years, there have been provided a large number of liquid jet type recording devices that eject an ink droplet on a recording medium such as a recording paper for recording an image or a character thereon. For example, a printer or a facsimile is an example thereof. The recording device supplies ink to a head chip from an ink tank through an ink supply pipe, and ejects ink onto the recording medium from a nozzle of the head chip for recording.
As illustrated in
As illustrated in
Further, the respective terminals 19a and 19b of the actuator plate 15 and the wirings 92 of the flexible substrate 90 are small in line width because those elements are arranged at narrow pitches. On the other hand, the actuator plate 15 is made of a ceramic-based piezoelectric material whereas the flexible substrate 90 is made of a resin material such as polyimide. For that reason, those members are largely different in linear thermal expansion coefficient from each other, and a difference in the amount of expansion and contraction between those members due to a temperature change becomes large. As a result, it is difficult to align the respective terminals of the actuator plate 15 with the wirings of the flexible substrate 90.
JP 09-29977 A discloses a configuration in which, in order to facilitate the connection of electric wirings even if the groove intervals of an ink chamber are narrowed, electrode extraction parts that are rendered conductive to an electrode disposed within the ink chamber is formed on the surface of a piezoelectric ceramic substrate, and the intervals of the electrode extraction parts are radially formed so as to be larger than the intervals of the electrodes. However, the technology of JP 09-29977 A has such a problem that the intervals of the electrode extraction parts are widened, and hence the piezoelectric ceramics substrate large in width is required, resulting in the upsized ink jet head.
The present invention has been made in view of the above-mentioned problems, and therefore an object of the present invention is to provide a head chip, a liquid jet head, a liquid jet recording device, and a method of manufacturing the head chip, which are capable of preventing short-circuit between terminals, and facilitating alignment when a flexible substrate is mounted.
In order to solve the above-mentioned problems, a head chip according to the present invention includes: a plurality of liquid jet channels formed in an actuator plate; nozzles that communicate with the plurality of liquid jet channels and eject liquid; a pair of piezoelectric elements that hold each of the plurality of liquid jet channels therebetween; common electrodes formed on surfaces of the pair of piezoelectric elements on the liquid jet channel side; drive electrodes formed on surfaces of the pair of piezoelectric elements, the surfaces being opposite to the surfaces on which the common electrodes are formed; common terminals connected to the common electrodes and formed on a surface of the actuator plate; an integrated plate that covers a plurality of the common terminals; and an integrated wiring that is formed on a surface of the integrated plate and integrates at least a part of the plurality of common terminals, in which the integrated wiring is connected to the common terminals through through-holes of the integrated plate, and in which the actuator plate includes integrated terminals connected to the integrated wiring and drive terminals connected to the drive electrodes, the integrated terminals and the drive terminals being arranged at an end thereof.
According to the present invention, an integrated wiring into which at least a part of the plurality of common terminals are integrated is formed, and thus the integrated terminal connected to the integrated wiring and the drive terminals connected to the drive electrodes are arranged at the end of the actuator plate. Therefore, the number of terminals is reduced as compared with a case in which all of the common terminals and the drive electrodes are arranged in line, and the respective terminals can be arranged at wide pitches. As a result, short-circuit between the terminals can be prevented. In addition, the line width of the respective terminals can be made larger, whereby alignment when the flexible substrate is mounted can be facilitated.
Further, the through-holes each desirably include a contact plug formed therein, and the integrated wiring is desirably connected to the common terminals through the contact plug formed in each of the through-holes of the integrated plate.
According to the present invention, the contact plug is provided, and hence the integrated terminal and the common terminal can be surely connected to each other.
Further, the integrated plate desirably has a linear thermal expansion coefficient equal to a linear thermal expansion coefficient of the actuator plate.
In this case, amounts of expansion and contraction due to a temperature change are equal to each other between the actuator plate and the integrated plate. Accordingly, the alignment of the through-holes of the integrated plate with respect to the common terminals of the actuator plate can be easily performed irrespective of temperature.
Further, the integrated plate is desirably a cover plate that covers the plurality of liquid jet channels.
In this case, it is unnecessary to provide an additional integrated plate, and hence the manufacturing costs can be reduced.
Further, the common electrodes are desirably ground electrodes.
In this case, the operation accuracy of the piezoelectric element can be improved.
Further, a pair of the integrated terminals connected to both ends of the integrated wiring are desirably arranged at both ends of a plurality of the drive terminals.
In this case, variations in potential of the plurality of common terminals can be reduced as compared with a case in which the integrated terminal is connected to only one end of the integrated wiring, thereby improving the operation accuracy of the piezoelectric element.
Meanwhile, a liquid jet head according to the present invention includes the head chip according to the present invention.
According to the present invention, there is provided the head chip which is capable of preventing short-circuit between the terminals, and hence there can be provided the liquid jet head excellent in electric reliability.
Meanwhile, a liquid jet recording device according to the present invention includes: the liquid jet head according to the present invention; liquid supply means for supplying a liquid to the plurality of liquid jet channels of the head chip; and recording medium conveying means for conveying a recording medium so as to pass through a position that faces the nozzles.
According to the present invention, there is provided the head chip which is capable of preventing short-circuit between the terminals, and hence there can be provided the liquid jet head excellent in electric reliability.
Meanwhile, a method of manufacturing the head chip according to the present invention includes: aligning the through-holes of the integrated plate to the common terminals formed on the surface of the actuator plate to join the integrated plate to the surface of the actuator plate with an adhesive; removing the adhesive that has flowed into the through-holes; and forming the contact plugs inside the through-holes.
According to the present invention, there can be provided the head chip which makes it possible to surely connect the contact plugs and the common terminals, and is excellent in the electric reliability.
According to the head chip of the present invention, the integrated wiring into which at least a part of the plurality of common terminals are integrated is formed, and the integrated terminals connected to the integrated wiring and the drive terminals connected to the drive electrodes are arranged at the ends of the actuator plate. Therefore, the number of terminals is reduced as compared with a case in which all of the common terminals and drive electrodes are arranged in line, and the respective terminals can be arranged at wide pitches. As a result, short-circuit between the terminals can be prevented. In addition, the line width of the respective terminals can be increased, and hence alignment when the flexible substrate is mounted can be facilitated.
In the accompanying drawings:
Hereinafter, a description is given of an embodiment of the present invention with reference to the accompanying drawings.
(Liquid Jet Recording Device)
As illustrated in
The pair of conveying means 2 and 3 include grid rollers 20 and 30 extending in the X direction, pinch rollers 21 and 31 extending in parallel to the grid rollers 20 and 30, and a drive mechanism (not shown) such as a motor, which axially rotates the grid rollers 20 and 30.
The ink supply means 5 includes an ink tank 50 in which ink is housed, and an ink supply pipe 51 that connects the ink tank 50 to the liquid jet head 4. There are provided a plurality of the ink tanks 50, and more specifically, ink tanks 50Y, 50M, 50C, and 50B for four kinds of ink consisting of yellow, magenta, cyan, and black are aligned in the Y direction. The ink supply pipe 51 is formed of a flexible hose having flexibility adaptive to the operation of the liquid jet head 4 (carriage 62).
The scanning means 6 includes a pair of guide rails 60 and extending in the X direction, a carriage 62 slidable along the pair of guide rails 60 and 61, and a drive mechanism 63 that moves the carriage 62 in the X direction. The drive mechanism 63 includes a pair of pulleys 64 and 65 disposed between the pair of guide rails and 61, an endless belt 66 winded around the pair of pulleys and 65, and a drive motor 67 that rotationally drives the pulley of the pair. The pair of pulleys 64 and 65 are disposed between both ends of the pair of guide rails 60 and 61, respectively, and arranged at an interval in the X direction. The endless belt 66 is disposed between the pair of guide rails 60 and 61, and the endless belt is coupled with the carriage 62. The plurality of liquid jet heads 4 are mounted on the carriage 62, and more specifically, liquid jet heads 4Y, 4M, 4C, and 4B for four kinds of ink consisting of yellow, magenta, cyan, and black are aligned in the X direction for mounting.
As illustrated in
As illustrated in
(Head Chip)
As illustrated in
More specifically, the head chip 41 illustrated in
The actuator plate 15 is a rectangular plate made of a piezoelectric material such as lead zirconate titanate (PZT). On one surface side of the actuator plate 15 concave groove-like channels 12 that are rectangular in cross section and extend in the lateral direction (hereinafter referred to as “Z direction”) of the actuator plate 15 are formed. A plurality of channels 12 are arranged at given intervals in the longitudinal direction (Y direction) of the actuator plate 15.
As illustrated in
Further, as illustrated in
As illustrated in
Further, a common electrode 18a is disposed on each jet channel 12A side of the piezoelectric bodies 17, and a drive electrode 18b is disposed on each dummy channel 12B side of the piezoelectric bodies 17. The common electrodes 18a and the drive electrodes 18b are band-like electrodes extending in the Z direction, and deposited on the upper portions of the side surfaces of the piezoelectric bodies 17. The two drive electrodes 18b disposed on a pair of piezoelectric elements 11 that hold the jet channel 12A therebetween, respectively, are mutually coupled with each other so as to be applied with the same voltage. All of the common electrodes 18a are grounded.
Further, as illustrated in
The cover plate 16 is a rectangular plate superimposed on the actuator plate 15, and disposed so as to cover the channels 12. On one surface side (opposite side of the actuator plate 15 side) of the cover plate 16, the concave groove-like ink chamber 10 that is rectangular in plan view and extends in the longitudinal direction (Y direction) of the cover plate 16 is formed. In the bottom surface of the ink chamber 10, rectangular ink introduction apertures 9 that pass through another surface side (actuator plate 15 side) of the cover plate 16 are formed. The ink chamber 10 communicates with the jet channels 12A through the ink introduction apertures 9. That is, the ink introduction apertures 9 are disposed above the jet channels 12A. On the other hand, no ink introduction apertures 9 are formed above the dummy channels 12B.
The passage substrate 42 illustrated in
Returning to
The nozzle cap 8 is a block body including an opening 8a into which the actuator plate 15 and the cover plate 16 are inserted, and is joined to the back surface (surface on the opposite side of the surface facing the recording medium S) of the nozzle plate 14.
(Integrated Wiring)
As illustrated in
In this embodiment, the cover plate 16 is arranged so as to cover the plurality of common electrodes 19a entirely and the ends of the integrated terminals 19d. Conversely, the plurality of common electrodes 19a entirely and the ends of the integrated terminals 19d are formed at a position where those elements are covered with the cover plate 16. The cover plate 16 is made of the same ceramic-based material as that of the actuator plate 15. For that reason, the cover plate 16 has the same linear thermal expansion coefficient as that of the actuator plate 15.
A groove 72 is formed along the end side of the cover plate 16 on the base end side. The groove 72 is formed so as to straddle all the common terminals 19a and the ends of the integrated terminals 19d. As illustrated in
The through-holes 74 are filled with a conductive material to form contact plugs 75, and the groove 72 is filled with a conductive material to form an integrated wiring 70. Ag paste or the like is used as the conductive material. The integrated wiring 70 is configured to electrically connect at least a part of the plurality of common terminals 19a. The integrated wiring 70 of this embodiment electrically connects all of the common terminals 19a through the contact plugs 75. As illustrated in
On the other hand, an end of the actuator plate 15 is equipped with one end of the flexible substrate 90. More specifically, the drive terminals 19b and the integrated terminals 19d aligned at the end of the actuator plate 15 are electrically connected to the wirings 92 formed on the flexible substrate 90 through an anisotropic conductive film (not shown) or the like. The other end of the flexible substrate 90 is mounted on the wiring substrate 45 illustrated in
As described above, the head chip 41 according to this embodiment includes the integrated wiring 70 that integrates all of the common terminals 19a, and has a configuration in which the integrated terminals 19d connected to the integrated wiring 70 and the drive terminals 19b connected to the drive electrodes are aligned at the end of the actuator plate 15. With that configuration, the number of terminals is reduced as compared with the related art in which all of the common terminals 19a and drive terminals 19b are aligned, and the respective terminals 19b and 19d can be arranged at wider pitches. As a result, short-circuit between the terminals can be prevented. Accordingly, there can be provided a liquid jet recording device excellent in electric reliability.
In addition, it is possible to increase the line width of the respective terminals 19b and 19d. As a result, when the flexible substrate 90 is mounted, it is possible to facilitate the alignment of the wirings 92b and 92d of the flexible substrate 90 with the respective terminals 19b and 19d of the head chip 41.
Further, in this embodiment, the integrated terminals 19d are arranged at the ends of the plurality of drive terminals 19b. With this configuration, the wirings 92 of the flexible substrate 90 are not connected to the common terminals 19a or the integrated terminals 19d over the drive terminals 19b. Accordingly, short-circuit between the drive terminals 19b and the common terminals 19a or the integrated terminals 19d due to the wirings 92 can be prevented.
Further, in this embodiment, the integrated terminals 19d are connected to both ends of the integrated wiring 70. With that configuration, variations of potentials at the plurality of common terminals 19a can be reduced as compared with a case in which the integrated terminal 19d is connected to only one end of the integrated wiring 70. As a result, it is possible to improve the operation accuracy of the piezoelectric elements, and liquid can be stably ejected from the jet channels.
(Manufacturing Method)
Next, a description is given of a method of manufacturing the head chip according to this embodiment. First, as illustrated in
Then, the through-holes 74 of the cover plate 16 are aligned to the common terminals 19a and the integrated terminals 19d formed on the actuator plate 15. When the ink introduction apertures 9 of the cover plate 16 are aligned to the jet channels 12A of the actuator plate 15, the common terminals 19a, the through-holes 74, and the ink introduction apertures 9 are formed at the corresponding positions as described above, whereby the alignment of the through-holes 74 with the common terminals 19a can be also performed at the same time. In this example, the cover plate 16 has the same linear thermal expansion coefficient as that of the actuator plate 15, and thus the amount of expansion and contraction is equal to each other between both of those members even if the ambient temperature changes. Accordingly, those members can be easily aligned irrespective of the ambient temperature.
Subsequently, the cover plate 16 is joined to the surface of the actuator plate 15 with an adhesive made of a resin material or the like. The adhesive is applied on the entire joint surface of the actuator plate 15 with the cover plate 16. In this case, when the cover plate 16 is pushed against the surface of the actuator plate 15, the adhesive may flow (overflow) into the through-holes 74 formed in the cover plate 16. When the contact plugs 75 are formed with the adhesive flowing into the through-holes 74, the contact plugs 75 and the common terminals 19a or the integrated terminals 19d cannot be electrically connected to each other.
Under the circumstances, the adhesive that has flowed into the through-holes 74 is removed. More specifically, the insides of the through-holes 74 are irradiated with a laser to remove the adhesive therefrom. In particular, the irradiation of an excimer laser or the like enables only a resin material of the adhesive to be selectively removed without need for removing a ceramic-based material of the actuator plate 15 and the cover plate 16. Alternatively, the surfaces of the actuator plate 15 and the cover plate 16 may be subjected to ashing to remove the adhesive inside the through-holes 74.
Then, as illustrated in
In this embodiment, the adhesive that has flowed into the through-holes 74 is removed to form the contact plugs 75. This enables the contact plugs 75, and the common terminals 19a and the integrated terminals 19d to be electrically connected to each other without fail.
In this modified example, however, there is a need to provide the integrated plate 80 for forming the integrated wiring 70 in addition to the cover plate 16. On the contrary, in the above-mentioned embodiment, the integrated wiring is formed on the cover plate itself, whereby the manufacturing costs can be reduced as compared with those of this modified example.
The technical scope of the present invention is not limited to the above-mentioned embodiment, but includes various modifications added to the above-mentioned embodiment without departing from the spirit of the present invention. That is, the specific materials and the layer configurations described in the embodiment are merely one example, and can be appropriately altered.
For example, in the above-mentioned embodiment, the nozzle openings are disposed at the end in the channel extending direction, but the present invention may be configured so that the nozzle openings are formed in the bottom surface of the jet channels.
In the above-mentioned embodiment, as illustrated in
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