JP4676466B2 - Inkjet head manufacturing method - Google Patents

Description

  The present invention relates to a method for manufacturing an inkjet head using laser processing.

  Conventionally, a method of manufacturing a nozzle plate for forming nozzles by laser processing has been disclosed. The laser processing machine used in this manufacturing method includes a laser transmitter and a processing table having a suction mechanism. The suction mechanism has a nozzle sheet for installing the nozzle plate. The nozzle sheet has a suction hole corresponding to each nozzle formed in the nozzle plate.

In order to form a nozzle plate using this laser processing machine, an unprocessed nozzle plate is placed on a nozzle sheet. In this state, the suction mechanism starts suction through the suction hole, and the laser transmitter irradiates laser light to form a nozzle on the nozzle plate. As a result, when the formed nozzle communicates with the suction hole, a by-product generated by laser processing is sucked into the suction mechanism, and the by-product is prevented from adhering to the periphery of the nozzle (for example, , See Patent Document 1).
Japanese Patent Laid-Open No. 2002-355977

  By the way, as one method of forming nozzles on the nozzle plate by laser light irradiation, there is a method of forming nozzles by irradiating laser light to form holes after the nozzle plate is attached to the head body. This method has a larger alignment accuracy between the nozzle plate and the head body than when the nozzle plate on which the nozzles are formed in advance is attached to the head body. There is an advantage that the adhesive does not enter the inside of the nozzle, but on the other hand, a hole is formed in the nozzle plate, and at the same time, a by-product by laser processing enters the inside of the head and adheres to the ink flow path. There is a problem. Such contamination in the ink flow path may disturb the flow of ink or embed bubbles and cause ejection failure. When trying to cope with this problem with the conventional technique as described above, gas is blown or sucked from the outside of the head, so that by-products accumulated in the nozzle formation hole of the nozzle plate are difficult to remove. When the nozzle is formed through the hole in the nozzle plate, the accumulated by-product tends to enter and adhere to the flow path, and the by-product once entered the flow path is removed. Is difficult and time consuming.

  Accordingly, an object of the present invention is to provide a nozzle that prevents by-products and foreign matters from entering the head when a nozzle is formed by irradiating a laser beam to a nozzle plate attached to the head body to form a hole. It is to provide a forming method.

In the ink jet head manufacturing method of the present invention, a nozzle plate is adhered to a head main body in which an internal flow path is formed to seal the internal flow path, and gas is sent to the internal flow path so that the air pressure in the internal flow path When the nozzle row is formed by irradiating the nozzle plate with laser light , dividing the nozzle row with a plurality of nozzles into several groups, and forming the nozzles in batches for each group Every time one group of nozzles is formed, the flow rate of the gas sent to the internal flow path is increased .

  According to the present invention, when the nozzle is formed on the nozzle plate attached to the head body, the air pressure inside the head is made higher than the air pressure outside the head with the nozzle plate as a boundary. At the same time, since the gas inside the head is ejected through the nozzle, by-products and foreign matters accompanying laser processing of the nozzle plate do not enter the head from the nozzle, and the inside of the head can be kept clean.

  Hereinafter, a first embodiment of an inkjet head of the present invention will be described with reference to the drawings. The ink jet head forms characters and images by ejecting liquid droplets onto a sheet-like recording medium.

  As shown in FIG. 1, the inkjet head 11 has a head body 12, a nozzle plate 13 bonded to the head body 12, and a circuit board (not shown) attached to the head body 12. The circuit board has a head driving IC.

  As shown in FIGS. 2 and 3, the head body 12 includes a substrate 14, a side wall 15 provided in a “U” shape on the substrate 14, and a drive provided on the substrate 14 inside the side wall 15. The column 16 as an element, the common liquid chamber 17 formed inside the side wall 15, the pressure chamber 18 communicating with the common liquid chamber 17 and provided between the columns 16, and the side wall 15 and the column 16 are bonded. The top plate 19 and a liquid supply unit 20 for supplying liquid to the common liquid chamber 17 are provided. Further, an electrode for applying a voltage to the column 16 is formed on the side surface of each column 16. The internal flow path of the present invention is a concept including the common liquid chamber 17 and the pressure chamber 18.

  The nozzle plate 13 is made of a square plate made of resin, for example, polyimide. As shown in FIG. 2, the nozzle plate 13 is bonded to the head body 12 with an epoxy adhesive. As shown in FIG. 1, for example, one nozzle row 24 is formed on the nozzle plate 13. The nozzle row 24 includes a plurality of nozzle groups 25. In the present embodiment, for example, first to third nozzle groups (groups) 25A, 25B, and 25C are included. The nozzle groups 25A, 25B, and 25C include a plurality of nozzles 26 that are simultaneously formed in one process of laser light irradiation. In the present embodiment, for example, three nozzles 26 are included in one nozzle group 25. However, the number of nozzle groups 25 and the number of nozzles 26 included in the nozzle group 25 are not limited to this.

  The pressure chamber 18 communicates with the nozzles 26 of the nozzle plate 13. The support column 16 is formed by bonding two piezoelectric members made of PZT (lead zirconate titanate). The two piezoelectric members are bonded so that the polarization directions are opposite to each other.

  When the user instructs the ink jet recording apparatus equipped with the ink jet head 11 to start printing in a state where the pressure chamber 18 is filled with liquid, a control unit (not shown) of the ink jet recording apparatus performs printing on the ink jet head 11. The signal is output to the head driving IC. The head drive IC that has received the print signal applies a drive pulse voltage to the support 16 via the electrode. Accordingly, the pair of left and right support columns 16 are separated from each other so as to bend by performing shear mode deformation. Then, by returning these to the initial position and pressurizing the liquid in the pressure chamber 18, the liquid droplets are ejected from the nozzle 26 with vigorous force.

  Next, the air blower 27 used for manufacturing the ink jet head 11 will be described with reference to FIG. When the nozzle 26 is formed by laser processing, the blower 27 sends gas to the common liquid chamber 17 and the pressure chamber 18 so that the pressure inside the inkjet head 11 is higher than the outside pressure. . In the present embodiment, air is used as the gas, but is not limited to this. As the gas, in addition to air, an inert gas such as nitrogen or helium may be used. When such an inert gas is used as the gas, generation of by-products during laser processing can be minimized.

  The blower 27 includes a blower 31 that is a gas supply source, a tube 32 that connects the blower 31 and the liquid supply unit 20 of the head body 12, a chamber 33 and a pressure sensor 34 that are interposed in the middle of the tube 32, have. The blower 31 can send air toward the inkjet head 11 at a relative pressure of about 0.1 Pa. The chamber 33 is provided at a position between the blower 31 and the liquid supply unit 20. The chamber 33 is a storage unit that temporarily stores a gas therein, and has a volume sufficiently larger than the volumes of the common liquid chamber 17 and the pressure chamber 18 of the inkjet head 11. As will be described later, air is leaked from the nozzle 26 after the nozzle 26 is formed on the nozzle plate 13 by laser processing. However, since a sufficient amount of air is stored in the chamber 33 at a sufficient pressure, even if the air flows out from the nozzle 26, the air pressure in the inkjet head 11 rapidly decreases. Since the pressure sensor 34 detects the air pressure in the vicinity of the ink jet head 11, the air pressure in the ink jet head 11 is increased by increasing the air flow rate of the blower 31 as the air pressure in the ink jet head 11 decreases. Can be recovered.

  Then, the manufacturing method of the inkjet head 11 using this air blower 27 and the laser processing machine 35 is demonstrated. As shown in FIG. 2, the nozzle plate 13 with no nozzles is simply aligned and bonded to the head body 12 that has been assembled in advance to create the pressure chamber 18 and the common liquid chamber 17. As a result, the pressure chamber 18 and the common liquid chamber 17 are sealed. At this time, since the nozzle 26 is not formed on the nozzle plate 13, strict alignment is not required when the nozzle plate 13 is bonded.

  The laser processing machine 35 used for nozzle formation includes, for example, a laser transmitter 41, a mirror, a mask, a lens, and the like. The laser transmitter 41 is an excimer laser transmitter.

  As shown in FIG. 4, when a laser beam (excimer laser beam) 42 is irradiated from the laser transmitter 41 toward the nozzle plate 13, a concave portion 43 that becomes the nozzle 26 is formed by a photochemical reaction. The nozzle 26 is formed by pulse shots of the laser beam 42 several tens to several hundreds of times, for example.

  Prior to laser processing, the pressure in the pressure chamber 18 and the common liquid chamber 17 of the inkjet head 11 is higher than 1 atmosphere which is an external pressure (atmospheric pressure). In this state, the blower 31 once stops driving. As shown in FIG. 5, when the pulse shot of the laser beam 42 is continuously performed, the depth of the recess 43 that becomes the nozzle 26 becomes deeper. When irradiation with the laser beam 42 is further continued, the recess 43 communicates with the pressure chamber 18 as shown in FIG. At this time, since the bottom surface of the concave portion 43 is formed in an arc shape, a location where the concave portion 43 and the pressure chamber 18 first communicate with each other is a central portion of the concave portion 43. When the nozzle 26 communicates with the pressure chamber 18 in this central portion, as indicated by an arrow, an air stream flows from the pressure chamber 18 toward the outside. When irradiation with the laser beam 42 is continued in this state, the residual portion 44 remaining around the nozzle 26 is removed. Debris 45 of the nozzle plate 13 generated from the residue portion 44 rides on the air stream and is discharged to the outside of the inkjet head 11.

  The plurality of nozzles 26 included in each nozzle group 25 are collectively formed in one process by the laser light 42 that is branched and adjusted from the single laser transmitter 41. When the formation of one nozzle group 25 is completed, the blower 31 increases the flow rate of air sent to the inkjet head 11. When the nozzle 26 is formed, air flows out from the nozzle 26. In the present embodiment, the air pressure in the pressure chamber 18 and the common liquid chamber 17 is kept constant by increasing the flow rate of the air sent from the blower 31.

  The pressure in the pressure chamber 18 and the common liquid chamber 17 is sensed by the pressure sensor 34. When the air pressure in the pressure chamber 18 and the common liquid chamber 17 is recovered to a predetermined pressure higher than the atmospheric pressure by driving the blower 31, a process of forming the next nozzle group 25 is started. Thus, every time the formation of the nozzle group 25 is completed, the flow rate of the gas sent by the blower 31 is increased stepwise, and the pressure in the pressure chamber 18 and the common liquid chamber 17 is kept constant. The formation of all the nozzle groups 25 included in the nozzle row 24 is completed, and the inkjet head 11 is completed by attaching a circuit board or the like thereto.

  FIG. 7 shows the inkjet head 11 manufactured by the above method. As shown in the figure, the nozzle 26 is formed in a tapered shape. The nozzle diameter A of the nozzle 26 is 10 to 50 μm. The height dimension B of the pressure chamber 18 is 300 μm. The thickness dimension C of the nozzle plate 13 is 25 to 100 μm.

  In the ink jet head manufacturing method of the first embodiment, the nozzle plate 13 is bonded to the head body 12 in which the internal flow path is formed to seal the internal flow path, and the gas is sent to the internal flow path to send the pressure of the internal flow path. Then, the nozzle plate 24 is formed by irradiating the nozzle plate 13 with the laser beam 42.

  According to this configuration, since the atmospheric pressure of the common liquid chamber 17 and the pressure chamber 18 that are internal flow paths is higher than the external atmospheric pressure, when the nozzle 26 is formed on the nozzle plate 13, gas is generated from the formed nozzle 26. Is discharged to the outside. For this reason, even when the nozzle 26 is formed by irradiating the laser beam 42 with the nozzle plate 13 bonded to the head body 12, the fragments 45 of the nozzle plate 13 are transferred to the pressure chamber 18 and the common liquid chamber 17. The situation where it adheres can be prevented. As a result, the pressure chamber 18 and the common liquid chamber 17 can be kept clean, and the occurrence of turbulent flow due to the broken pieces 45 and the inclusion of bubbles can be prevented.

  In this case, the gas is supplied to the internal channel via the liquid supply unit 20 provided in the head body 12 so as to be continuous with the internal channel. According to this configuration, gas can be supplied to the internal flow path via the liquid supply unit 20. Thereby, it is possible to serve as a supply port for supplying gas to the liquid supply unit 20, and it is not necessary to provide a supply port separately, and the structure of the inkjet head 11 can be effectively utilized.

  In this case, the nozzle row 24 includes a plurality of nozzle groups 25, and each nozzle group 25 includes a plurality of nozzles 26 that are collectively formed by irradiation with laser light 42. According to this configuration, the nozzle row 24 is sequentially formed for each nozzle group 25.

  In this case, every time the formation of one nozzle group 25 is completed, the flow rate of the gas sent to the internal flow path is increased, and the atmospheric pressure in the internal flow path is kept constant. In the inkjet head manufacturing method of the present embodiment, when one nozzle group 25 is formed, the gas accumulated in the common liquid chamber 17 and the pressure chamber 18 is discharged from the formed nozzle 26 to the outside. For this reason, every time one nozzle group 25 is completed, the flow rate of the gas discharged from the nozzle 26 increases, and the atmospheric pressure in the common liquid chamber 17 and the pressure chamber 18 decreases. According to this configuration, each time the formation of one nozzle group 25 is completed, the flow rate of the gas sent to the internal flow path is increased, so that the atmospheric pressure in the common liquid chamber 17 and the pressure chamber 18 can be maintained substantially constant. . Thereby, when the nozzle 26 is formed by irradiating the laser beam 42, the air flow discharged from the nozzle 26 is not weakened, and the common liquid chamber 17 and the pressure chamber 18 can be kept clean.

  In this case, the gas is temporarily stored by a storage unit provided at a position between the gas supply source and the liquid supply unit. When the nozzles 26 are formed on the nozzle plate 13, gas flows out from the formed nozzles 26, and the atmospheric pressure in the internal flow path of the head body 12 decreases. According to this configuration, even when the pressure in the internal flow path is about to decrease due to the formation of the nozzle, it is possible to prevent the pressure in the internal flow path from being rapidly decreased due to the gas accumulated in the storage unit. Can do. Thereby, formation of the next nozzle group 25 can be started quickly.

  Next, a second embodiment of the inkjet head 11 will be described with reference to FIG. The inkjet head 11 according to the second embodiment has the same structure as that of the first embodiment, but the manufacturing process is different. For this reason, the part of the manufacturing process different from the first embodiment will be mainly described, and portions common to the first embodiment will be denoted by common reference numerals and description thereof will be omitted.

  As shown in FIG. 2, a nozzle plate 13 with no nozzles is simply positioned and bonded to a pre-assembled head body 12. The configuration of the blower 27 is the same as that of the first embodiment. The laser beam machine 35 used for nozzle formation is the same as that in the first embodiment. In the second embodiment, a shielding plate 51 that is a transparent plate is disposed between the laser transmitter 41 of the laser processing machine 35 and the nozzle plate 13. The shielding plate 51 is made of a glass plate and has a laser beam 42 transparency. The shielding plate 51 is disposed in parallel with the nozzle plate 13.

  As shown in FIG. 8, when the laser beam 42 is irradiated from the laser transmitter 41 toward the nozzle plate 13, a recess 43 that becomes the nozzle 26 is formed. The nozzle 26 penetrating the nozzle plate 13 is formed by performing pulse shots of the laser beam 42 several tens to several hundreds of times.

  When the nozzle 26 communicates with the pressure chamber 18 at the central portion of the recess 43, an air stream flows from the pressure chamber 18 toward the outside. When irradiation with the laser beam 42 is continued in this state, the residual portion 44 remaining around the nozzle 26 is removed. Debris 45 of the nozzle plate 13 generated from the residue portion 44 rides on the air stream and is discharged to the outside of the inkjet head 11. At this time, since the shielding plate 51 is disposed, the fragments 45 of the nozzle plate 13 are blown off along the shielding plate 51. For this reason, this broken piece 45 is prevented from adhering to the laser transmitter 41. The nozzle group 25 is sequentially formed while increasing the flow rate of air sent by the blower 31 in a stepwise manner, and the inkjet head 11 is completed.

  According to the second embodiment, the shielding plate 51 that is transparent to the laser light 42 is disposed between the laser processing machine 35 for irradiating the laser light 42 and the nozzle plate 13. According to this configuration, by providing the shielding plate 51, the debris 45 of the nozzle plate 13 is prevented from being blown against the laser processing machine 35 by riding on the gas flowing out from the nozzle 26 during nozzle formation. be able to. Thereby, it can prevent that the fragment 45 adheres to the laser processing machine 35, and can prevent the situation where the power of the laser beam 42 and a beam profile change.

  Next, a third embodiment of the inkjet head 11 will be described with reference to FIG. The inkjet head 11 according to the third embodiment has the same structure as that of the first embodiment and the second embodiment, but the manufacturing process is different. For this reason, the manufacturing process of a part different from 2nd Embodiment is mainly demonstrated, and the code | symbol same about the location which is common in 2nd Embodiment is attached | subjected, and description is abbreviate | omitted.

  As shown in FIG. 2, a nozzle plate 13 with no nozzles is simply positioned and bonded to a pre-assembled head body 12. The configuration of the blower 27 is the same as that of the first embodiment. The laser processing machine 35 used for nozzle formation is the same as that of the second embodiment. In the third embodiment, a shielding plate 61 that is a transparent plate is disposed between the laser transmitter 41 of the laser processing machine 35 and the nozzle plate 13. The shielding plate 61 is made of a glass plate and has a laser beam 42 transparency. As shown in FIG. 9, the arrangement angle of the shielding plate 61 is different from that of the second embodiment, and the shielding plate 61 is tilted in the rotation direction about the direction of the nozzle row formed on the nozzle plate 13. Are arranged.

  As shown in FIG. 9, when the laser beam 42 is irradiated from the laser transmitter 41 toward the nozzle plate 13, a recess 43 that becomes the nozzle 26 is formed. When the nozzle 26 communicates with the pressure chamber 18 at the central portion of the recess 43, an air stream flows from the pressure chamber 18 toward the outside. When irradiation with the laser beam 42 is continued in this state, the residual portion 44 remaining around the nozzle 26 is removed. Debris 45 of the nozzle plate 13 generated from the residue portion 44 rides on the air stream and is discharged to the outside of the inkjet head 11. At this time, since the shielding plate 61 is disposed, the fragments 45 of the nozzle plate 13 are blown obliquely upward along the shielding plate 61. The nozzle group 25 is sequentially formed while increasing the flow rate of air sent by the blower 31 in a stepwise manner, and the inkjet head 11 is completed.

  According to the third embodiment, the shielding plate 61 is disposed so as to be inclined in the rotation direction with the direction of the nozzle row formed on the nozzle plate 13 as an axis. If the shielding plate 51 is simply provided as in the second embodiment, the debris 45 bounced by the shielding plate 51 swirls in a spiral shape, returns to the vicinity of the nozzle plate 13 again, and adheres to the nozzle plate 13. There is a fear. According to this configuration, the debris 45 bounced by the shielding plate 61 is blown obliquely upward, so that the debris 45 returns to the vicinity of the nozzle plate 13 again and is prevented from adhering to the nozzle plate 13. be able to.

1 is a perspective view showing an ink jet head according to a first embodiment. FIG. 3 is a perspective view showing a manufacturing process of the ink jet head shown in FIG. 1. The schematic diagram which shows the air blower used for the manufacturing process of the inkjet head shown in FIG. Sectional drawing which shows the next process of the manufacturing process of the inkjet head shown in FIG. Sectional drawing which shows the recessed part formed in the nozzle plate by the manufacturing process shown in FIG. Sectional drawing which shows the next process of the manufacturing process shown in FIG. Sectional drawing which shows the peripheral structure of the nozzle of the inkjet head manufactured by the manufacturing process of 1st Embodiment. Sectional drawing which shows the manufacturing process of the inkjet head which concerns on 2nd Embodiment. Sectional drawing which shows the manufacturing process of the inkjet head which concerns on 3rd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Inkjet head, 12 ... Head main body, 13 ... Nozzle plate, 17 ... Common liquid chamber, 18 ... Pressure chamber, 20 ... Liquid supply part, 24 ... Nozzle row, 25 ... Nozzle group, 26 ... Nozzle, 31 ... Blower, 33 ... chamber, 35 ... laser beam machine, 42 ... laser beam, 51, 61 ... shielding plate

Claims (5)

After the nozzle plate is adhered to the head body that has built the internal flow path, the internal flow path is sealed, gas is sent to the internal flow path, and the air pressure in the internal flow path is made higher than the air pressure outside the head main body. The plate is irradiated with laser light to form nozzles ,
Divide the nozzle array with multiple nozzles into several groups, and increase the flow rate of gas sent to the internal flow path every time nozzle formation of one group is completed when forming nozzles in groups. An inkjet head manufacturing method characterized by the above. 2. The ink jet head manufacturing method according to claim 1 , wherein a transparent plate that is transparent to the laser beam is disposed between the laser processing machine for irradiating the laser beam and the nozzle plate. The inkjet head manufacturing method according to claim 2 , wherein the transparent plate is inclined in a rotation direction about the nozzle row direction. Ink jet head manufacturing method according to any one of claims 1 to 3, characterized in that the gas is supplied to the internal flow passage through the liquid supply portion provided in the head body so as to be continuous to the internal channel . The inkjet head manufacturing method according to claim 4 , wherein the gas is temporarily stored by a storage unit provided between the gas supply source and the liquid supply unit.

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