JP3690031B2 - Inkjet recording head - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ink jet recording head that is excellent in nozzle position accuracy and suitable for high speed and high print quality while arranging a large number of nozzle holes.
[0002]
[Prior art]
High-quality and high-speed color printing is required for inkjet printers, and measures such as higher resolution, use of various inks such as six colors, and increase in the number of nozzle holes due to multi-rows are necessary. ing. As a result, measures have been taken such as producing a very large flow path unit to increase the number of nozzle holes (Japanese Patent Laid-Open No. 7-227966) or installing a plurality of heads in parallel. (JP-A-6-24123).
[0003]
[Problems to be solved by the invention]
When a plurality of heads are installed in parallel for increasing the number of colors or increasing the number of nozzle holes, there is a problem that the relative positional accuracy of the nozzle holes formed in these heads is poor. As a means for solving this, there is a method of finely adjusting the position of the head installed on the carriage, but due to strict accuracy requirements, adjustment accuracy is ensured, and even if possible, a great amount of adjustment time is required. It is not a realistic means.
[0004]
In addition, when the flow path unit is increased in size, the inkjet recording head is required to have a large number of pressure generation chambers and pressure generation chambers arranged in one flow path unit, although extremely fine processing dimensions are required. If the dimensions of the supply port, which is the inlet of the ink, are separated from each other in the same flow path unit, a large variation in manufacturing occurs.
[0005]
The present invention has been made in view of such problems, and an object of the present invention is to provide an ink jet recording that is highly accurate with respect to a large number of nozzle hole arrangements and that effectively copes with discharge variations and manufacturing costs. Is to provide a head. In particular, the present invention provides a head structure suitable for an ink jet recording head having a pressure element and a driving electrode on the surface of a substrate on which a pressure generating chamber is formed facing the nozzle plate.
[0006]
[Means for Solving the Problems]
An ink jet recording head of the present invention to solve such a problem, a single nozzle plate in which the nozzle groups of the nozzle holes a plurality arranged in a row are multiple forms formed, and the nozzle plate a flow path unit forming the result pressure generating chamber in a space made in the flow path forming member, a housing for holding bonded to the flow path unit, for ink pressurization provided corresponding to said pressure generating chamber and pressurizing element, and a cable connected via the conductor portion to the pressurized圧素Ko, a plurality so as to correspond to the channel unit for each of the nozzle groups, each corresponding to a channel unit of the plurality of A plurality of the cables are provided, one end of each of the plurality of cables is connected to the pressurizing element via the conductor portion between the flow path units , and the other end is formed by the nozzle plate of the casing. The The surfaces are those pull out in the opposite direction.
[0007]
[Action]
As a result, a plurality of nozzle hole arrays can be arranged on one nozzle plate, the positional accuracy of all nozzle holes is improved, and high print quality can be achieved at high speed.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Therefore, details of the present invention will be described below based on the illustrated embodiment.
[0009]
FIG. 1 is a perspective view showing an embodiment of a recording head of the present invention, FIG. 2 is a sectional view thereof, and FIG. 3 is a partially enlarged view thereof.
[0010]
In the figure, reference numeral 2 denotes a nozzle plate, which is composed of a metal plate having a thickness of about 50 μm, and a number of nozzle holes 3 are formed by pressing or electroforming so as to communicate with a pressure generating chamber 9 described later. A plurality of nozzle holes 3 formed in two rows at the same pitch (for example, 1/300 inch pitch) in a row (the positions of the nozzle holes in the two rows are shifted from each other by a half pitch) are arranged as nozzle groups 4a, 4b, 4c, and 4d. In this case, they are provided in one nozzle plate in parallel with each other, and an opening 17 is provided between the nozzle groups.
[0011]
Reference numerals 5a, 5b, 5c, and 5d are flow path units provided for each of the nozzle groups 4a, 4b, 4c, and 4d, and each flow path unit includes a common flow path unit. The flow path units 5a, 5b,... Are composed of a flow path forming member 6, a pressurizing element 8, an electrode connected to the pressurizing element 8, a protective film, and a substrate 7 on which the pressurizing element 8 is formed. A pressure generating chamber 9 and an ink supply port 10 that are arranged at the same pitch and communicate with each nozzle hole, and a common ink chamber 11 and an ink introduction port 12 that communicate with each pressure generating chamber are formed.
[0012]
The pressure generating chamber 9 and the ink supply port 10 are formed in a space sandwiched between the flow path forming member 6 and the nozzle plate 2, and the flow path units 5a, 5b, 5c, and 5d are the nozzle groups 4a, 4b, 4c, and 4d. Are fixed to the surface of the nozzle plate in parallel with each other. 4 is a view when only the nozzle plate 2 and the flow path units 5a, 5b,.
[0013]
The pressurizing element 8 is formed on the substrate 7 in each pressure generating chamber 9 so as to face the nozzle plate 2, and here is a heating resistor element for generating bubbles. Reference numeral 13 denotes a housing that adheres to and holds the nozzle plate 2 and the flow path unit, and has an ink path 14 communicating with the ink chamber 11 therein, and one end of the ink path 14 has a narrowed tip. It is a needle 15.
[0014]
The above-described opening 17 formed in the nozzle plate 2 is configured so that a part of the substrate 7 is exposed. The exposed portion of the substrate is formed directly on each of the pressure elements 8 or on the substrate 7. The conductor portions 18 to be connected are formed in a line at equal pitches via the driving transistor. Although details of the electrode pattern on the substrate 7 from the pressurizing element 8 to the conductor portion 18 are omitted here, each pressurizing is performed on the substrate using a thin film process as in JP-A-55-90376 and others. The pattern wiring is performed for each element.
[0015]
Reference numerals 16a, 16b, 16c, and 16d in the figure are drive signal transmission flexible cables, and copper foils are exposed at equal pitches at the ends, and this copper foil is solder, gold / tin, or The cables 16a, 16b... Are led out through the gaps or notches provided in the housing 13 and between the flow path units 5a, 5b, 5b, 5c, and the like. The drawn cables 16 a, 16 b,... Are connected to a circuit board 19 attached to the back of the housing 13.
[0016]
Although not shown in the drawing, the connection portion between the conductor portion 18 and the cable 16, that is, the cable 16a and 16d connection portions around the opening 17 and both sides is avoided from contact with ink, and the housing 13 and the nozzle. In order to further reinforce the bonding with the plate 2, a resin mold is applied.
[0017]
The recording head is mounted on the carriage of the printer main body mechanism, and a cable (not shown) connected to a connector (not shown) provided on the circuit board 19 is connected to a cable from a waveform generating circuit of the printer main body. Print on top. For example, by mounting ink cartridges of four colors Y, M, C, and Bk on the needle 15, printing can be executed while ejecting ink droplets of each color for each nozzle group.
[0018]
According to this configuration, the exposure of the conductor portion connected to the pressurizing element and the space for connecting the cable to the conductor portion are ensured between the flow path unit and the plurality of nozzle rows as one nozzle. It is formed on a plate. By accommodating all the nozzle holes in a plurality of rows in one nozzle plate, the relative positional deviation amount of the nozzle holes can be set to 10 μm or less including not only the same nozzle group but also all nozzle groups.
[0019]
In particular, in this type of head structure in which the pressure elements are formed on the surface of the substrate facing the nozzle plate, it is difficult to arrange three or more nozzle hole groups in parallel for cable extraction. According to this, multiple rows of nozzles can be arranged. Furthermore, an opening is provided in the nozzle plate, and the conductor portion on the substrate is exposed in the opening portion so that the cable is brought into contact, so that the connection of each cable and the drawing out to the back can be realized well.
[0020]
Further, by holding the nozzle plate 2 with the housing 13, it is possible to prevent the deformation of the enlarged nozzle plate and further the weakened nozzle plate with the opening, and the stabilization of the nozzle hole position and the discharge performance. Care is taken not to cause deterioration.
[0021]
As in this example, each flow path unit is provided for each nozzle group to reduce the size of each flow path unit. Variations in speed, discharge amount, and stability can be minimized. Furthermore, if a plurality of common flow path units are arranged as in the present embodiment, variations among the units can be suppressed, and manufacturing can be simplified.
[0022]
In the embodiment, one nozzle group is constituted by a plurality of nozzle holes arranged in two rows at the same pitch in a row, and is arranged with a half-pitch shift between rows. The nozzle groups are arranged in the carriage movement direction at intervals necessary for the cable connection. However, the nozzle hole position varies depending on the specifications, such as the nozzle hole position suitable for the purpose, that is, the nozzle hole array suitable for monochrome high resolution printing and the nozzle hole array suitable for color printing with a plurality of color inks. Can be arranged.
[0023]
FIG. 5 shows another embodiment of the present invention. A plurality of nozzle holes 3 provided in a row at a pitch of 1/300 inch are arranged in the six-row nozzle plate 2 as nozzle groups 24a, 24b, 24c, and 24d, and have openings 17 at three locations. . The cables 26 a, 26 b, and 26 c that are conductively connected to the substrate exposed at the opening 17 are wired to the side of the nozzle plate 2, that is, upward in the drawing, and then pulled out rearward along the housing 13. Further, the adjacent nozzle groups are connected with a common cable to improve efficiency in manufacturing and assembling.
[0024]
FIG. 6 shows another embodiment of the present invention, in which a plurality of nozzle holes 3 provided in a line at a pitch of 1/300 inch are arranged in the nozzle plate 2 as nozzle groups 34a, 34b, 34c, 34d. . A conductor 38 connected to each pressurizing element is exposed by pulling out the substrate between the nozzle groups 34a, 34b, etc. to both sides of the nozzle plate 2, and the leading ends of the cables 36a, 36b are connected to the portions. Thus, the cable is drawn backward along the housing 13 on both sides of the nozzle plate. Two cables are shared between the nozzle groups.
[0025]
In the recording head of the embodiment shown in FIGS. 5 and 6, by configuring so that different types of ink can be supplied to each nozzle row, printing can be executed while ejecting ink droplets of six colors in one pass of the carriage.
[0026]
FIG. 7 is a sectional view showing another embodiment of the present invention, and FIG. 8 is an enlarged sectional view of a part around the pressure chamber. FIG. 9 is a view from the back, and the arrangement of the nozzle holes is the same as FIG. In the figure, reference numeral 52 denotes a nozzle plate, which is composed of a silicon plate having a thickness of about 100 to 300 μm. A large number of nozzle holes 53 are formed in rows at the same pitch by etching or laser processing so as to communicate with the pressure generating chamber 59. Drilled in parallel across the rows.
[0027]
Reference numerals 55a, 55b, 55c, and 55d are flow path units, and the flow path units 55a, 55b, 55c, and 55d include a flow path forming member 56 and a pressurizing element 58, and are arranged at the same pitch as the nozzle holes inside. A pressure generation chamber 59 and an ink supply port 60 communicating with the nozzle hole 53 and a common ink chamber 61 communicating with each pressure generation chamber are formed. The casing 63 is bonded to the flow path forming member 56 and the nozzle plate 52 from the back, and the pressure generating chamber 59 and the ink supply port 60 are in a space sandwiched between the flow path forming member 56, the nozzle plate 52 and the casing 63. Is formed. The housing 63 has an ink path 62 communicating with the ink chamber 61.
[0028]
The electrodes connected to the pressurizing element 58 and the pressure generating element and their protective films are directly formed on the back surface of the nozzle plate 52. Here, the pressurizing element 58 is a nozzle in the pressure generating chamber 59 near the nozzle hole 53. It is a heating resistor element for generating bubbles formed on the plate 52.
[0029]
Between the flow path unit, the back surface of the nozzle plate 52 is configured to be exposed from the opening 67 formed in the flow path forming member 56 and the housing 63. The conductor portions 68 to be connected are formed in a line at an equal pitch directly or via a driving transistor formed on the substrate.
[0030]
In the figure, reference numerals 66a, 66b, 66c, 66d denote flexible cables for driving signal transmission, and copper foil exposed at the tips of the flow path units 55a, 55b,... Is connected to the conductor portion 68 by solder, gold / tin, gold / gold joint or the like, and the cables 66a, 66b, 66c, 66d are drawn out to the back. The cables 66a, 66b,... Drawn out are connected to a circuit board (not shown) attached to the back of the housing 13.
[0031]
According to the present embodiment, since the pressurizing element and the conductor portion are formed on the back surface of the nozzle plate, without providing an opening in the nozzle plate, the conductor portion is exposed rearward between the flow path unit and the cable. It is possible to connect. All the nozzles are housed in one plate to improve the positional accuracy.
[0032]
Further, in this embodiment, a method of sealing one surface of the pressure generating chamber with a housing is used, and the structure is simplified. In addition, the nozzle plate was held in the casing to ensure its strength.
[0033]
FIG. 10 shows still another embodiment of the present invention, and its discharge principle has already been described in Japanese Patent Laid-Open No. 5-50601. That is, the thin diaphragm 78 is bent and deformed by applying an electric field between the electrode 91 formed in the minute recess 81 on the glass substrate 77 and the silicon substrate 75 as the flow path forming member. 86 is conductively connected from the nozzle plate side to the conductive portion 88 on the glass substrate exposed to the opening 87 of the nozzle plate 72 and the conductive portion 92 on the silicon substrate which is a common electrode. It is pulled out between.
[0034]
According to the present embodiment, it is possible to arrange three or more nozzle rows, which has conventionally been difficult with this type of recording head, on one nozzle plate.
[0035]
【The invention's effect】
Above, in the present invention as described, made from a sheet of the nozzle plate, the nozzle plate and the flow path forming member in which the nozzle groups of the nozzle holes a plurality arranged in a row are multiple forms formed space Thus a flow path unit forming a pressure generating chamber, a housing for holding bonded to the flow path unit, and pressurizing element for ink pressurization provided corresponding to said pressure generating chamber, said and a cable connected via the conductor portion pressurizing element, a plurality so as to correspond to the channel unit for each of the nozzle groups, providing a plurality of said cable such that each corresponding to a channel unit of the plurality of In addition, the plurality of cables are connected at one end to the pressurizing element via the conductor portion between the flow path units, and the other end is opposite to the surface on which the nozzle plate of the housing is formed. of pull out in the direction And those are, therefore a plurality of nozzle columns can be formed on a single nozzle plate, can improve the positional accuracy of the nozzle holes, a high-quality printing can be performed at high speed.
[Brief description of the drawings]
FIG. 1 is an external perspective view showing an embodiment of an ink jet recording head of the present invention.
FIG. 2 is a sectional view of the embodiment.
FIG. 3 is a partially enlarged cross-sectional view of the periphery of the pressure generating chamber according to the embodiment.
FIG. 4 is an explanatory view of the embodiment as seen from the back.
FIG. 5 is an external perspective view showing another embodiment of the ink jet recording head of the present invention.
FIG. 6 is an external perspective view showing another embodiment of the ink jet recording head of the present invention.
FIG. 7 is a cross-sectional view showing another embodiment of the ink jet recording head of the present invention.
FIG. 8 is a partially enlarged cross-sectional view around the pressure generating chamber of the embodiment.
FIG. 9 is an explanatory view of the embodiment as seen from the back.
FIG. 10 is a cross-sectional view showing another embodiment relating to the periphery of the pressure generating chamber of the ink jet recording head of the present invention.
[Explanation of symbols]
2 Nozzle plate 3 Nozzle hole 5 Flow path unit 6 Flow path forming member 7 Substrate 8 Pressurizing element 9 Pressure generating chamber 11 Ink chamber 13 Housing 16 Drive signal transmission cable 17 Opening 18 Conductor

Claims (5)

Channel unit in which the nozzle group including a plurality arranged nozzle holes in rows were formed with a single nozzle plate which is several shapes formed, the thus pressure generating chamber in a space made in the nozzle plate and the flow path forming member When a housing for holding bonded to the flow path unit, and pressurizing element for ink pressurization provided corresponding to said pressure generating chamber, is connected via a conductor portion in the pressurized圧素Ko that a cable, a plurality so as to correspond to the channel unit for each of the nozzle groups, corresponding with the plurality providing the cable so that each channel unit of the plurality of, said plurality of cables the channel unit between one end connected respectively through the conductive portion to the pressurizing element, and characterized by being pull out in the opposite direction to the nozzle plate is formed a surface of the other end the housing Inkjet The recording head.  2. The ink jet recording head according to claim 1, wherein the nozzle plate has an opening exposing the conductor portion between the flow path unit and the cable is connected to the conductor portion in the opening. 3. . 2. The ink jet recording head according to claim 1 , wherein the cable is led out to the rear of the casing between the channel units and through a hole or notch provided in the casing .  The ink jet recording head according to claim 1, wherein the pressure element is a heating resistor formed on a nozzle plate.  2. The ink jet recording head according to claim 1, wherein the pressurizing element comprises a diaphragm forming a pressure generating chamber and an electrode for deforming the diaphragm with electrostatic force.

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