JP2001301171A - Ink jet head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve such a problem that a quantity of ink to be used increases by effects of a not used nozzle array when a printer is constituted not to use the one nozzle array for printing with the use of an ink jet head which can print by discharging ink from a plurality of nozzle holes of each of two nozzle arrays. SOLUTION: Two sheets of photomasks to be used in processing an upper substrate 1 are changed, whereby this ink jet head is formed with nozzle holes not opened and shut to ink chambers 5 of the nozzle array not used for printing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet head mounted on an ink jet printer which performs printing by discharging ink droplets onto a recording medium. In particular, the present invention relates to a structure of an ink jet head which discharges ink droplets by deforming a diaphragm using electrostatic force.

[0002]

2. Description of the Related Art An ink jet head for discharging ink droplets by using electrostatic force is disclosed in, for example, US Pat.
No. 20,375, and JP-A-5-50601. In the ink jet heads described in these publications, the bottom surface of the pressure chamber communicating with the ink nozzle is formed by a vibrating plate capable of being elastically displaced in an out-of-plane direction, and electrodes are arranged facing the vibrating plate. By applying a drive voltage pulse between the diaphragm and the electrode, the diaphragm is displaced by electrostatic force, and ink droplets are ejected from the ink nozzles according to the displacement of the diaphragm.

Japanese Patent Application Laid-Open No. H9-1997 discloses a technique for more stably ejecting fine ink droplets in response to a demand for higher quality of output characters and images in accordance with high performance of information processing apparatuses.
No. 323409, Japanese Patent Application Laid-Open No. 10-193625, etc., have two nozzle rows, and the nozzle holes of the first nozzle row are arranged at a pitch of the nozzle holes with respect to the nozzle holes of the second nozzle row. The nozzle holes are arranged in a staggered manner so as to be located between the nozzle holes in the directions. With this configuration, an ink jet head having a dot density twice as high as that of a head having one nozzle row is obtained. In addition, in response to a recent demand for colorization, a two-color ink jet head that prints main color ink from the first nozzle row and prints sub-color ink from the second nozzle row,
The second nozzle row is divided into three regions, and Y (yellow), M (magenta), C
2. Related Art An inkjet head for color printing for printing (cyan) color ink has been proposed.

[0004]

The ink jet head as described above is a model to be mounted on a printer for monochromatic printing, a model to be mounted on a printer for two color printing, and a color printing, depending on the market and application required. Each head, such as a model mounted on a printer for printing, is individually designed and manufactured according to the type of printing.

[0005] However, depending on the type of printer that cannot be expected to sell as much as possible, such as a model to be introduced into a market where the market size is not so large or a model to be introduced strategically to grasp market trends, two-color printing is not possible. Head mounted on a printer for printing and head mounted on a printer for monochrome printing,
Also, there is a demand to share an inkjet head mounted on a printer having the same dot density on a recording medium and different specifications, such as a head mounted on a color printing printer and a head mounted on a monochrome printing printer. There is also a demand for a single-color printing printer to share an inkjet head to be mounted with a printer having a different dot density on a recording medium. For example, when mounted on a printer for color printing, the ink droplets ejected from the nozzle holes in the first and second nozzle rows are both used for printing, and when mounted on a printer for monochrome printing, the first nozzle is used. Some applications use only ink droplets ejected from nozzle holes in a row. Therefore,
In some applications, nozzles on one nozzle row side are not used for printing, and such specifications have the following problems.

In both two-color printing and color printing, the color of ink for printing from the nozzle holes in the first nozzle row is different from the color of ink for printing from the nozzle holes in the second nozzle row. There is a separate ink intake for each or for each type of ink used. Here, when the nozzle holes in the second nozzle row are not used for printing, it is conceivable that the path for supplying ink from the ink tank to the second nozzle row side is shut off and the ink intake port is opened to the atmosphere. In this case, when the ink suction operation is performed from the nozzle side by the pump mounted on the printer, such as the initial filling cleaning operation and the cleaning operation, the air is sucked from the second nozzle row, so that the ink suction operation can be performed. There is a disadvantage that it disappears.

When an ink supply path for supplying ink from an ink tank to be supplied to the first nozzle row is also connected to the ink intake port on the side of the second nozzle row, an initial filling cleaning operation, cleaning By performing an operation or the like, ink is also sucked from the unused second nozzle row side, so that there is a disadvantage that the consumption of ink not used for printing increases.

Further, since the appearance is the same, it is difficult to distinguish between a nozzle mounted on a printer using both nozzle rows for printing and a printer mounted on a printer using only one nozzle row for printing. There is a problem that.

Accordingly, an object of the present invention is to provide an ink jet head which can be individually mounted on printers of various specifications by making a minimum change.

[0010]

SUMMARY OF THE INVENTION Accordingly, the present invention provides an ink supply path, an ink chamber communicating with the ink supply path,
In an ink jet head including a plurality of ink nozzles communicating with the ink chambers and a plurality of pressure generating means for applying an ejection pressure for ejecting ink droplets to the ink chambers, a plurality of the ink chambers are A first group of ink chambers provided with ink nozzles and arranged in a row, and a second group of ink chambers arranged in a row without the ink nozzles are formed. The ink-jet head of the present invention closes all the nozzle holes on the nozzle row not used for printing as described above, so that when the ink is sucked from the nozzle side by the pump mounted on the printer, the printing is performed. In addition, the influence of the nozzle array not used for the above is eliminated, and the normal suction operation can be performed.

The second nozzle plate of the second ink chamber group, which corresponds to the first nozzle plate on which the nozzles of the first nozzle group are formed, is an identification unit that can be identified from the first nozzle plate. It is desirable to have.

According to the above configuration, it is possible to distinguish whether or not the ink jet head is a type in which the nozzle holes on one nozzle row are used for printing.

[0013]

Embodiments of the present invention will be described below with reference to the accompanying drawings to explain the present invention in further detail.

FIG. 1 is a top view of the ink jet head of the present invention, and FIG. 2 is a sectional view of the ink jet head shown in FIG.

The ink jet head of this embodiment is of a face eject type in which ink droplets are ejected from nozzle holes provided on the upper surface of the substrate, and is of an electrostatic drive type.
The inkjet head has a three-layer structure in which three substrates 1, 2, and 3 are sequentially stacked.

The intermediate substrate 2 is, for example, a silicon substrate, and a plurality of ink chambers formed on the surface of the substrate 2 in parallel from one end at equal intervals and having bottom walls functioning as diaphragms (pressure generating means) 4a. (Pressure chamber) 5a and a common ink reservoir 6 for supplying ink to each ink chamber 5a.
a are formed by etching. A common electrode 7a is formed on the upper surface of the substrate 2.

The upper substrate 1 bonded to the upper side of the intermediate substrate 2 is, for example, a silicon substrate, like the intermediate substrate 2, and has an upper surface portion of the ink chamber 5a on the first ink chamber group side. Nozzle holes 8a for the number of ink chambers 5a are formed at positions corresponding to the respective ink chambers 5a. An orifice 9a is formed on the upper surface of the intermediate portion between the ink chamber 5a and the ink reservoir 6a.

The lower substrate 3 joined to the lower surface of the intermediate substrate 2 is made of, for example, borosilicate glass, and the upper surface thereof has the vibration chambers 10a corresponding to the number of the ink chambers 5a at positions corresponding to the respective ink chambers 5a. Are formed, and an individual electrode 11a is formed on the bottom surface of each vibration chamber 10a. The lower substrate 3 is provided with an ink inlet 12a, and is arranged so as to be below the ink reservoir 6a when the substrates 2 and 3 are joined.

The above-mentioned three substrates are joined, and the vibration chamber 10a is hermetically sealed from the outside air using a sealing material 13a such as a resin to complete the shape of the ink jet head.

The ink is supplied from an ink tank to an ink inlet 12a via an ink supply tube, and is supplied to an ink reservoir 6a and an orifice 9 formed in the intermediate substrate 2.
a, filling the ink chamber 5a.

The end of each individual electrode 11a is connected to an electrode terminal 14a.
An FPC (flexible print circuit) cable on which a driver IC is mounted is connected to the terminal portion and the common electrode 7a.

The distance between the individual electrode 11a and the diaphragm 4a is 1 μm.
m from the driver IC to the individual electrodes 1
By applying a voltage pulse to 1a, diaphragm 4a
Is bent toward the individual electrode 11a by the electrostatic force,
By turning off the voltage pulse, the diaphragm 4a returns to its original position by its spring force. Due to this restoration operation, the internal pressure of the ink chamber rapidly rises, and ink droplets are ejected upward from FIG. 2 from the nozzle 8a. Further, the vibration plate 4a bends toward the individual electrode 11a again by the reaction of the spring force, so that ink is supplied from the reservoir 6a to the ink chamber 5a through the orifice 9a.

The above structure has been described with reference to the left half of the figure, but a similar structure is also provided on the right half of the figure, and the only difference is the column A side (first line) shown in FIG. The only difference is that there is no nozzle hole corresponding to the nozzle hole 8a on the ink chamber group side). In FIG. 2, the structure on the side of the column B is configured so as to be axisymmetric with respect to the structure on the side of the column A. Is attached as b on the column B side, and the description is omitted.

As described above, the ink jet head of this embodiment has a structure in which nozzle holes are not formed in the nozzle row portion indicated by row B on the right half side of the figure, and is used for discharging ink provided on both left and right sides of the figure. This is an inkjet head that has been improved to be mounted on a printer that uses only the structure on the left side of the structure for printing. When the ink jet head is mounted on the printer, an initial filling cleaning for filling the ink into the head is performed. Further, during use, cleaning for discharging bubbles, thickened ink, foreign matter, and the like in the head is performed. In these cleanings, a cap is normally pressed against the surface of the step 15 of the upper substrate 1 shown in FIGS. 1 and 2 from the upper side in the figure, and suction is performed by a pump through a tube or the like connected to the cap.

The position of the nozzle row shown as row A in FIG.
The distance between the positions where the nozzle rows of the rows should be formed is 0.6 m
m, the cap cannot be pressed individually for each nozzle row. Therefore, one common cap is pressed against both the nozzle rows A and B, and the suction operation of the ink from the nozzle holes is performed at the same time.

The ink jet head shown in this embodiment does not open the nozzle holes on the row B, so that the cleaning operation can be efficiently performed on the printer even in a state where it is opened to the atmosphere without connecting anything to the ink intake port 12b. Can be. Therefore, it is possible to function as a printer for monochrome printing. Further, since the consumption of ink not used for printing is reduced, the running cost of the printer can be reduced.

The ink jet head of this embodiment is provided with a projection 16 as an identification portion near the electrode terminal 14b on the right side in the figure. By providing the projections 16, the electrode terminal 14a on the side used for printing and the electrode terminal 1 on the side not used for printing are provided.
4b can be distinguished by looking at the appearance.
As a result, even when the FPC cable is connected to the electrode terminal 14a, the terminal to be connected can be immediately identified, and a defect of connecting to the opposite terminal can be eliminated.

In addition, since it is possible to distinguish the ink jet head from the type using the nozzle holes in both the nozzle rows A and B by looking at the external appearance, it is erroneously mounted on another type of printer. Can be eliminated.

The ink-jet head of this embodiment uses a silicon substrate, a glass substrate, or the like as a material and performs processing using a photolithography technique, an etching technique, a joining technique, or the like. Here, a method of processing the upper substrate 1 will be described.

FIG. 3 is a diagram showing the arrangement of the upper substrate on the material substrate. In this figure, four upper substrates 21 are arranged on a material substrate 20. The processing of the material substrate 20 is performed by applying a photoresist on the surface of the substrate, exposing a pattern shape on the photomask to the photoresist using a photomask, developing the photoresist, and performing etching to form a shape. ing. The material substrate 20 is processed from both sides of the front and back sides of the drawing, the nozzle holes 8 are created by exposure and etching from the back side of the drawing, and the through holes 25, 26, and 27 are formed on both sides of the front and back sides of the drawing. Exposure from the
Created by etching. The selection of forming / not forming the nozzle holes on the B-row side and forming / not forming the protrusions 16 is performed by selecting one photomask used for processing from the front side and one photomask used for processing from the back side in the drawing. Total 2
If the number of sheets is changed, it is possible to easily change the ink jet head without changing the processing steps.

The process of processing the intermediate substrate 2, the process of processing the lower substrate 3, the process of joining these three substrates, and the process of cutting into individual ink jet heads are based on the presence or absence of nozzle holes on the B row. Processing can be performed in the same process regardless of the presence or absence of the projections 16. Therefore, in the standard processing step of an ink jet head that forms a nozzle hole in both the A / B nozzle rows and does not have the projections 16 and performs printing from both the A row and the B row nozzle rows, the processing of the upper substrate 1 is performed. By changing the two photomasks used for the above, the ink jet head shown in this example can be formed without changing the processing steps.

In this embodiment, the nozzle holes on the A-row side are used for printing, and the nozzle holes on the B-row side are closed. Is also practical.

Also, in this example, the figure is shown for a case where the number of nozzles in one nozzle row is eight.
, 128, 256, etc., even if the number changes.

Further, in this example, the staggered nozzle arrangement is such that the positions where the nozzle holes in row B are to be formed between the two nozzle holes in row A in the pitch direction. However, the present invention can also be applied to a configuration in which the nozzle holes in the rows A and B are arranged in parallel.

In this embodiment, the face eject type in which the ink droplets are ejected from the nozzle holes provided on the upper surface of the substrate has been described, but the edge eject type in which the ink droplets are ejected from the nozzle holes provided at the end of the substrate is also applicable. It is possible.

[0036]

As described above, the ink jet head of the present invention can perform the cleaning operation of the printer normally because all the nozzle holes on one side are closed. Further, since the consumption of waste ink not used for printing can be reduced, the effect of reducing running costs can be obtained.

[Brief description of the drawings]

FIG. 1 is a top view of an inkjet head according to the present invention.

FIG. 2 is a sectional view taken along line AA of the inkjet head shown in FIG.

FIG. 3 is a diagram showing an arrangement of an upper substrate on a material substrate of the ink jet head shown in FIG. 1;

[Explanation of symbols]

 1. Upper substrate 2, 21. Intermediate substrate 3. Lower substrate 4a, 4b, diaphragm 5a, 5b, ink chamber 6a, 6b, ink reservoir 7a, 7b, common electrode 8. Nozzle holes 9a, 9b orifices 10a, 10b vibration chambers 11a, 11b individual electrodes 12a, 12b ink inlets 13a, 13b sealing materials 14a, 14b electrode terminals 15 ..Steps 16 Projections 20 Material substrates 25, 26, 27 Through holes

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Hiroyuki Maruyama 3-3-5 Yamato, Suwa City, Nagano Prefecture Seiko Epson Corporation F-term (reference) 2C057 AF99 AG11 AG12 AG54 AG99 AP01 AP13 AP31 BA04 BA15

Claims (2)

[Claims] An ink supply path, an ink chamber communicating with the ink supply path, an ink nozzle communicating with the ink chamber, and a discharge pressure for discharging ink droplets are applied to the ink chamber. A plurality of the ink chambers, wherein the plurality of ink chambers are arranged in a row with the ink nozzles, and the first ink chamber group is arranged in a row with the ink nozzles. An ink-jet head, wherein the ink-jet head is formed in a second ink chamber group. 2. A second nozzle plate of the second ink chamber group, which corresponds to a first nozzle plate on which the nozzles of the first nozzle group are formed, and is identifiable from the first nozzle plate. The ink jet head according to claim 1, wherein the ink jet head has a portion.