JP2977872B2 - Ink jet head and processing method thereof - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an on-demand type ink-jet head using a piezoelectric vibrator and a method for processing the same, and more particularly, to bonding between an internal electrode and an external electrode of a laminated piezoelectric vibrator. The present invention relates to a stable inkjet head and a processing method thereof.

FIG. 4 is a view for explaining a conventional example of an on-demand type ink jet head. FIG. 4 (a) is a front view, and FIG. 4 (b) is a sectional view taken along the line AA in FIG. It is. In the figure,
41 is a substrate, 42 is a laminated piezoelectric vibrator, 43 is a groove perforated in the longitudinal direction of the laminated piezoelectric vibrator to separate individual vibrators,
44 is a filler, 45 is a flow path plate joined on the laminated piezoelectric vibrator, 46 is a pressurized liquid chamber, 47 is a nozzle, 48 is a protection plate, 49 is an external electrode on the individual side, 50 is an external electrode on the common side, 51 is an individual side internal electrode for driving the laminated piezoelectric vibrator, and 52 is a common side internal electrode having a thickness of about several μm. Here, each of the individual-side internal electrodes 51 is connected at an end to a corresponding individual-side external electrode 49, and a common-side internal electrode 52 is connected to an end of the common-side external electrode 49.
Connected to 50.

The operation of the on-demand type inkjet head having the above-described configuration is performed by first operating between the individual-side external electrode 49 and the common-side external electrode 50 of the vibrator 54 selected based on a command of a drive circuit (not shown) of the circuit board 55. By applying a driving pulse voltage to the vibrator 54, the vibrator 54 is displaced in thickness and compresses the pressurized liquid chamber 46.

The pressurized liquid chamber 46 is filled with ink from a liquid supply port 57 and communicates with a common liquid chamber 58 to contain ink.
The recording is performed by ejecting more ink droplets.

However, for the laminated piezoelectric vibrator 42 having the internal electrodes 51 and 52 having a thickness of several μm, the groove 43 formed to form the vibrator 54 is a thin groove of about 100 μm. At present, it is most suitable to perform groove processing with a saw.

FIG. 5 is an explanatory view of groove processing by a dicing saw. The laminated piezoelectric vibrator 42 is provided with an individual side external electrode 49 and a common side external electrode 50, and the individual side external electrode 49 is provided with an individual side internal electrode 51. The common-side internal electrodes 52 are connected to the common-side external electrodes 50, respectively. Reference numeral 59 denotes a blade of a dicing saw. The blade 59 drills a groove (not shown) in the longitudinal direction as shown by an arrow in the laminated piezoelectric vibrator 42 installed in parallel with the drilling direction. 58 indicated by a broken line is a groove bottom of the groove 43 at a position deeper than the individual side external electrode 49.

However, when the groove processing is performed by a dicing saw, the run-out of the blade 59 increases when the blade 59 enters and exits the laminated piezoelectric vibrator 42. Due to this vibration, the laminated piezoelectric vibrator 42 is vibrated, and since the contact area between the individual side internal electrode 51 and the common side internal electrode 52 and the individual side external electrode 49 and the common side external electrode 50 is very small, the connection portion is peeled off. The defect that had occurred. Moreover, it is difficult at present to completely eliminate this vibration.

Further, after the flow path plate 45 and the laminated piezoelectric vibrator 42 are joined, surface finishing of the nozzle surface of the nozzle 47 is performed, and the flow path plate is placed on the nozzle 47 side of the laminated piezoelectric vibrator 42 for this surface finishing processing.
A protective plate 48 made of a material equivalent to that of the laminated piezoelectric vibrator 42, that is, a material capable of forming a groove is provided in contact with 45. But protection plate
Grinding is performed to obtain a flatness between the pressurized liquid chamber 46 and the laminated piezoelectric vibrator 48, so that external electrodes on the upper surface of the laminated piezoelectric vibrator 42 cannot be provided.
There was a problem that the top layer of No. 42 did not contribute to the thickness displacement.

Object The present invention has been made in view of the above situation, and provides a connection portion between each external electrode and an internal electrode of a common external electrode and an individual external electrode substantially inside a laminated piezoelectric vibrator. It is an object of the present invention to provide an ink jet head which eliminates the problem of disconnection at a connection portion and eliminates the need for a protective plate, and a method for processing the same.

Configuration According to the present invention, in order to achieve the above object, (1) a groove parallel to a laminated piezoelectric vibrator is provided, and a common electrode and an individual electrode of the laminated piezoelectric vibrator are provided on a vibrator having an individual electrode divided by the groove. A voltage is applied between them to deform the thickness, and the thickness deformation compresses the heating liquid chamber provided in the flow path plate joined on the laminated piezoelectric vibrator, and is provided at the tip of the pressurized liquid chamber. In the ink jet head that ejects ink from the nozzles, the individual electrode side shallow groove and the common electrode side deep groove provided substantially perpendicular to the groove provided in parallel with the laminated piezoelectric vibrator, and each of the shallow groove and the deep groove Consisting of external electrodes provided in the groove and on the surface of the laminated piezoelectric vibrator, further,
(2) Processing a groove parallel to the laminated piezoelectric vibrator, and applying a voltage between the common electrode and the individual electrode of the laminated piezoelectric vibrator to the vibrator having the individual electrode divided by the groove to deform the thickness. Processing of an ink jet head for compressing a pressurized liquid chamber provided in a flow path plate joined on the laminated piezoelectric vibrator by the thickness deformation, and ejecting ink from a nozzle provided at a tip of the pressurized liquid chamber; In the method, before processing the groove in the laminated piezoelectric vibrator, a shallow groove on the individual electrode side and a deep groove on the common electrode side are provided substantially perpendicular to the groove, and the lamination is performed in each of the shallow groove and the deep groove. Providing a step of providing an external electrode on the surface of the piezoelectric vibrator; and (3) providing the common electrode side deep groove at the center of the laminated piezoelectric vibrator, and forming the individual electrode side shallow groove into the laminated piezoelectric vibrator. At both ends of the shallow groove and the deep groove And a step of providing an external electrode on the surface of the laminated piezoelectric vibrator. (4) The common electrode side deep groove is symmetrically provided near a central axis of the laminated piezoelectric vibrator, and the individual electrode side shallow groove is provided. Are provided at both ends of the laminated piezoelectric vibrator, and an external electrode is provided in each of the shallow groove and the deep groove and on the surface of the laminated piezoelectric vibrator. Hereinafter, a description will be given based on examples of the present invention.

FIG. 1 is a side sectional view of a main part laminated piezoelectric vibrator for explaining one embodiment of a method for processing an ink jet head according to the present invention, and a flow path plate is omitted. In the figure, 1 is a substrate, 2 is a laminated piezoelectric vibrator, 3 is a layer of the laminated piezoelectric vibrator on which no grooves are formed, 10 is a groove bottom, 4 is a common internal electrode of the laminated piezoelectric vibrator, and 5 is an individual side. Internal electrode, 6 is a common electrode side deep groove, 7 is an individual electrode side shallow groove, 8 is a common side external electrode, and 9 is an individual side external electrode. The common-side external electrode 8 is connected to the common-side internal electrode 4 in the common-electrode-side deep groove 6 and extends to the outer surface of the laminated piezoelectric vibrator 2, and the individual-side external electrode 9 is formed in the individual-electrode-side shallow groove 7. Connected to the individual side internal electrode 5, the laminated piezoelectric vibrator 2
To the outer surface of the

The processing method of the inkjet head of the present invention having the above configuration will be described below.

(1) The substrate 1 is joined to the laminated piezoelectric vibrator 2 having no external electrodes.

(2) The common electrode side deep groove 6 and the individual electrode side shallow groove 7 are machined in a direction perpendicular to the groove to be machined (the paper surface direction: not shown). The depth of the deep groove 6 on the common electrode side is deeper than the shallow groove 7 on the individual electrode side.
, The shallow groove 7 on the individual electrode side is
Shallower than 10. The groove bottom 10 is deeper than the internal electrodes 4 and 5.
The groove shape is preferably a tapered groove.

(3) The common-side external electrodes 8 and the individual-side external electrodes 9 are provided by sputtering or the like. At this time, when the electrode is formed by making the groove shape tapered, a strong one is obtained.

(4) Groove processing is performed with a dicing saw to form a vibrator. At this time, the laminated piezoelectric vibrator 2 is integrally connected with the hatched portion 3 below the groove bottom 10 and has a comb-teeth shape in which only the groove portion is separated.

(5) The subsequent steps are the same as the conventional steps, and the common side external electrode 8 and the individual side external electrode 9 of the vibrator separated by the groove are connected by a conducting wire on the circuit board (not shown) side.

 Seal the conductor.

 The groove is filled with an elastic agent such as silicone rubber.

 The channel plate is joined to the laminated piezoelectric element.

 Finish the nozzle surface.

FIG. 2 is a sectional view of a main part showing another embodiment of the present invention.
In the figure, 11 is a substrate, 12 is a laminated piezoelectric vibrator, 13 is a layer of the laminated piezoelectric vibrator that has not been subjected to groove processing (in the paper direction), and 14 is a common internal electrode having no electrodes at both ends of the laminated piezoelectric element. , 15
Is an individual side internal electrode having no electrode in the center, 16 is a common electrode side deep groove provided in the center of the laminated piezoelectric vibrator, 17, 18
Are shallow grooves on the individual electrode side provided at both ends of the laminated piezoelectric vibrator, 19 is a common external electrode, 20 and 21 are individual external electrodes, 2
2 is a flow path plate, 23 and 24 are pressurized liquid chambers provided at the center of the flow path plate, 25 and 26 are nozzles, 27 and 28 are conducting wires for applying external electrode driving pulses on the individual electrode side, Reference numeral 29 denotes a filler, reference numeral 30 denotes a groove bottom when the groove processing is performed, and therefore, the laminated piezoelectric vibrator 12 is connected at a hatched portion.

The processing method of the inkjet head of the present invention having the above configuration will be described below.

(1) Multilayer piezoelectric vibrator without substrate 11 and external electrodes
Join with 12.

(2) In the direction perpendicular to the groove to be processed, a common electrode side deep groove 16 is provided at the center of the laminated piezoelectric vibrator 12, and individual electrode side shallow grooves 17 and 18 are provided near both ends.

(3) The common side external electrode 19 is connected by sputtering or the like so as to be connected to the common side internal electrode 14 from the common electrode side deep groove 16 to the upper surface of the laminated piezoelectric vibrator 12. At the same time, the individual-side external electrodes 20 and 21 are formed from the shallow individual-electrode-side grooves 17 and 18 at both ends of the upper surface of the laminated piezoelectric vibrator 12 by the sputtering, and are connected to the individual-side internal electrodes 15.

(4) Groove processing is performed with a dicing saw to form a vibrator.

(5) Filler 29 is filled with deep groove 16 on the common electrode side and shallow groove 1 on the individual electrode side
Fill 7,18.

(6) The flow path plate 22 is joined on the laminated piezoelectric vibrator 12.

The above inkjet head is one laminated piezoelectric vibrator
With two sets of nozzles formed on the nozzle 12, a two-color integrated head or a head having twice the number of nozzles can be processed with about half the number of groove processing.

FIG. 3 is a sectional view of a main part showing another embodiment of the present invention.
In the figure, 31 is a substrate, 32 is a laminated piezoelectric vibrator, 33 is a layer of the laminated piezoelectric vibrator on which a groove (in the paper surface direction) is not processed, and 34 is a vicinity of a central portion of the laminated piezoelectric vibrator indicated by an axis 0-0. , Two common electrode side deep grooves provided axially symmetrically, 35 and 36 are individual electrode side shallow grooves provided near both ends, 37 is a common side internal electrode, 38 is an individual side internal electrode, and 39 is a common side External electrodes 40 and 41 are individual side external electrodes. Common side external electrode 39 is common side internal electrode 37
The individual external electrodes 40 and 41 are connected to the individual internal electrodes 38 and extend to both ends of the upper surface of the multilayer piezoelectric element 32.

The processing method of the inkjet head of the present invention having the above configuration will be described below.

(1) Multilayer piezoelectric vibrator without substrate 31 and external electrodes
Join with 32.

(2) Central axis OO in the direction perpendicular to the groove to be machined
Two common electrode side deep grooves 34 are provided near the central axis, and individual electrode side shallow grooves 35 and 36 are provided near both ends.

(3) The common side external electrode 39 is connected by sputtering or the like so as to connect to the common side internal electrode 14 from the common electrode side deep groove 34 to the upper surface of the laminated piezoelectric vibrator 32. At the same time, the individual-side external electrodes 40 and 41 are connected to the individual-side internal electrodes 38 from the shallow grooves 35 and 36 on both sides of the upper surface of the laminated piezoelectric vibrator 32 by the sputtering.

(4) A groove is formed by a dicing saw to form a vibrator, and the groove is filled with an elastic agent (not shown).

(5) The shaft OO part is cut, and two inkjet heads are simultaneously processed.

Effects As is apparent from the above description, the present invention has the following effects.

(1) Since the connecting portion between the internal electrode and the external electrode is located substantially inside from both end faces of the laminated piezoelectric vibrator, the vibration is not generated where the blade of the dicing saw cuts the connecting portion. The problem that the connection portion is reduced and the connection portion is disconnected is eliminated, and the external electrode is not damaged at the time of the nozzle processing, so that the protective plate is not required, and thus the surface grinding step is not required.

(2) With one laminated piezoelectric vibrator, a two-color integrated inkjet head or an inkjet head having twice the number of nozzles can be processed with approximately half the number of groove processing.

(3) By processing two sets of inkjet heads on one laminated piezoelectric vibrator symmetrically with respect to the axis, and cutting the inkjet heads along the axis of symmetry, it is possible to reduce man-hours required to process a plurality of units at the same time.

[Brief description of the drawings]

FIG. 1 is a sectional side view of an essential part for explaining a method of processing an ink jet head of the present invention, FIG. 2 is a sectional side view of another embodiment of the present invention, and FIG. 4 (a) and 4 (b) are schematic views of a conventional inkjet head using a laminated piezoelectric vibrator.
FIG. 5 is an explanatory diagram of groove processing of the laminated piezoelectric vibrator. 1,11,31 …… Substrate, 2,12,32 …… Laminated piezoelectric vibrator, 6,16,3
4 ... deep groove on common electrode side, 7, 17, 18, 35, 36 ... shallow groove on individual electrode side, 4, 14, 37 ... common electrode on common side, 5, 15, 38 ... internal electrode on individual side, 8 , 19,39 …… External electrodes on the common side, 9,20,21,40,41…
... External electrodes on the individual side.

Continued on the front page (72) Inventor Osamu Naruse 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Company (72) Inventor Shuzo Matsumoto 1-3-6 Nakamagome, Ota-ku, Tokyo Co., Ltd. Ricoh (72) Inventor Tomoaki Nakano 1-3-6 Nakamagome, Ota-ku, Tokyo Ricoh Co., Ltd. (56) References JP-A-60-90770 (JP, A) JP-A-63-99951 (JP) , A) JP-A-62-56150 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B41J 2/16 B41J 2/045 B41J 2/055

Claims (2)

(57) [Claims] A laminated piezoelectric vibrator is provided with a groove parallel thereto, and a thickness is changed by applying a voltage between a common electrode and an individual electrode of the laminated piezoelectric vibrator to a vibrator having individual electrodes which are divided by the groove. In the inkjet head, the thickness deformation deforms a pressurized liquid chamber provided in a flow path plate joined on the laminated piezoelectric vibrator, and ejects ink from a nozzle provided at a tip of the pressurized liquid chamber. A shallow groove on the individual electrode side and a deep groove on the common electrode side provided substantially perpendicular to the groove provided in parallel with the laminated piezoelectric vibrator, and the inside of each of the shallow groove and the deep groove and the surface of the laminated piezoelectric vibrator. And an external electrode provided on the ink jet head. 2. A groove parallel to the laminated piezoelectric vibrator is processed, and a voltage is applied between the common electrode and the individual electrode of the laminated piezoelectric vibrator by applying a voltage to the vibrator divided by the groove and having individual electrodes. An ink jet head that deforms, compresses a pressurized liquid chamber provided in a flow path plate joined on the laminated piezoelectric vibrator by the thickness deformation, and ejects ink from a nozzle provided at a tip of the pressurized liquid chamber. In the processing method, before processing the groove in the laminated piezoelectric vibrator, a shallow groove on the individual electrode side and a deep groove on the common electrode side are provided substantially perpendicularly to the groove, and in each of the shallow groove and the deep groove, A method of processing an ink-jet head, comprising a step of providing an external electrode on a surface of the laminated piezoelectric vibrator.