JP3223899B2 - Ink jet print head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a print head for an ink jet printer.

[0002]

2. Description of the Related Art In recent years, non-impact recording methods have attracted attention in that noise during recording is extremely low and high-speed recording is possible. Among them, the energy generation means gives ejection energy to the ink filled in the plurality of pressure chambers, and the liquid ink is ejected from the plurality of nozzles corresponding to these pressure chambers to adhere to the recording paper, thereby attaching characters and graphics. The ink jet recording method for performing such recording is a very effective recording method capable of performing high-speed recording and performing recording on plain paper without special fixing processing. Currently, various ink jet recording methods using this ink jet recording method are used. Expression printers have been proposed and commercialized.

This ink jet recording system can be roughly classified into three types: a continuous ejection type, an on-demand type (impulse type), and an electrostatic suction type. Among them, the on-demand type is a piezoelectric element only when necessary. Since ink droplets are ejected by driving an ejection energy generating element such as described above, there is no wasteful ink consumption, and the structure is very simple, so that its spread is expected.

In an on-demand type ink jet print head, wiping with a blade is performed to clean the nozzle surface. Conventional cleaning techniques include, for example, JP-A-10-44447, "Inkjet head maintenance device", JP-A-4-185450, "Inkjet printer cleaning device", and JP-A-7-17062, "Inkjet recording head" There is a technique described in.

Japanese Patent Laid-Open Publication No. Hei 10-44447 discloses that a plurality of ink colors are not mixed during cleaning.
A method is disclosed in which a surface corresponding to each ink color is provided on a wiping unit, and the surface is rotated to wipe off the ink of the corresponding color.

[0006] Japanese Patent Application Laid-Open No. 4-185450 discloses that
A cleaning method is disclosed which eliminates re-adhesion of ink and foreign matter to nozzles by providing a foam cleaning roller.

Further, Japanese Patent Application Laid-Open No. 7-17062 discloses that
In order to prevent the ink adhering to the nozzle surface from being swept away by the wiper at the time of wiping and mixing with other color inks, a groove is provided between the nozzle rows, and the ink scraped off during the cleaning operation by the wiping is formed by the groove. It is disclosed to gather into. FIG. 12 is a front view of the nozzle plate. As shown in the drawing, a nozzle row of each color of a black (hereinafter, Bk) nozzle row 1, a cyan (hereinafter, C) nozzle row 2, a magenta (hereinafter, M) nozzle row 3, and a yellow (hereinafter, Y) nozzle row 4 on the nozzle plate 10 is shown. Groove 5 between
Are formed.

[0008]

SUMMARY OF THE INVENTION The above-mentioned Japanese Patent Application Laid-Open No.
The technology described in Japanese Patent No. 44444 and Japanese Patent Application Laid-Open No. 4-185450 not only requires members and mechanisms having a complicated structure, but also complicates the operation and control, increases the size of the cleaning mechanism, and reduces the cost. There was a problem that the cost would be high.

In the technique described in Japanese Patent Application Laid-Open No. 7-17062, a groove is provided between nozzle rows. However, this is a simple single groove. There is a problem that the accumulated ink spreads again on the nozzle plate by wiping, and the effect of preventing color mixing is weakened, or the ink that has reattached may bend the ejection direction of the ink or cause non-ejection.

An object of the present invention has been made in view of the above-mentioned problems, and it is possible to continuously perform color mixing of ink on a nozzle plate and wiping without requiring special members or complicated mechanisms. An object of the present invention is to provide an ink jet print head capable of preventing occurrence of ejection failure due to re-adhering of scraped ink onto a nozzle plate, and suppressing deterioration of image quality.

[0011]

According to the present invention, there is provided an ink-jet type in which energy is supplied to ink filled in a plurality of pressure chambers by an energy generating means, and ink droplets are ejected from a plurality of nozzles corresponding to the pressure chambers. In the print head, a groove is formed between at least the nozzle rows of each color of the plurality of nozzle rows that eject different color inks on the nozzle plate, and the groove includes a portion having a groove width on which a capillary force acts. Features.

According to such a structure, the ink scraped off by the plate during the cleaning operation by wiping is collected in the groove. The collected ink is pulled by the capillary force acting on the portion, and is discharged out of the nozzle plate. Therefore, the ink does not enter the vicinity of the nozzle row of another color, and the color mixture of the ink on the nozzle plate does not occur. Further, even when repeated wiping is performed, since ink is not accumulated in the groove, the ink once scraped is less likely to re-adhere to the nozzle plate, and there is no occurrence of bending of the ink ejection direction or stopping of ejection. .

[0013] Such an ink jet print head is manufactured by forming a nozzle row on a plate made of austenitic stainless steel by pressing, forming the groove in the plate by etching, and manufacturing the nozzle plate. You.

Alternatively, such an ink jet print head is manufactured by manufacturing a nickel plate having nozzle rows by electroforming, forming the grooves in the nickel plate by etching, and manufacturing the nozzle plate. Is done.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an ink jet print head according to the present invention will be described with reference to the drawings.

FIG. 1 is a front view of a nozzle plate 10 of a first embodiment of an ink jet print head according to the present invention, and shows a Bk nozzle row 1, a C nozzle row 2, an M nozzle row 3, and a Y nozzle row 4. A groove 15 is provided between each nozzle row.

FIG. 2 is a sectional view showing a state of such wiping of the nozzle plate. The state where the attached ink 7 exists on the nozzle plate is shown.

Since the width of the groove 15 is smaller at both ends 15b than at the center 15a, the ink 8 scraped off by the plate 6 during the cleaning operation by wiping flows into the groove 15. When collected, the ink collected in the central portion 15a having a large groove width is applied to the end portion 1 having a small groove width.
By the capillary force of 5b, it is pulled to the end 15b,
Eventually, the ink moves to the outside of the nozzle plate, so that the ink does not enter the vicinity of the nozzle row of another color, and no color mixing of the ink occurs on the nozzle plate. In addition, even when wiping is performed repeatedly, since no ink is accumulated in the groove 15, the ink once scraped does not adhere to the nozzle plate again, and the ink ejection direction may be bent or the ejection may stop. Absent.

FIG. 3 is a view for explaining the relationship between the groove width between the central portion 15a and the end portion 15b of the groove, the length of the groove at the end portion 15b, and the depth of the groove. FIG. 4B is a partial front view of the plate, and FIG. 4B is a cross-sectional view of a central portion 15a of the groove.

As shown in FIG. 3A, when the groove width of the end 15b is w1, for example, 0.05 mm ≦ w1
≦ 0.1 mm. The lower limit of w1 is determined by manufacturing conditions. For such a groove width w1, it is preferable that the groove width of the central portion 15a be 1.2 × w1 ≦ w2 ≦ 5 × w1. Further, the length L1 of the groove of the end 15b is L1 ≧ w1,
That is, it is preferable to set the groove width w1 of the end 15b to be equal to or more than w1. Also, as shown in FIG. 3B, it is preferable that the depth h of the groove in the central portion 15a is h ≦ w1, that is, the groove width w1 of the end portion 15b is equal to or less than w1. The depth h is controlled by the etching time when forming the groove. Therefore, the depth of the groove at the end 15b is the same as the depth h of the groove at the center 15a.

Upper limit of width w1 of groove at end 15b, length L1
And the lower limit of the depth h are determined from the viewpoint of effectively operating the capillary force.

It is needless to say that the length of the groove in the central portion 15a needs to be longer than the length of the nozzle row.

FIG. 4 shows another embodiment of the nozzle plate of the ink jet print head according to the second embodiment of the present invention.

A groove 25 extends in parallel with the nozzle row.
a and a portion 25b extending in a direction perpendicular to the nozzle row is formed in an L-shape, and the groove width of the portion 25b perpendicular to the nozzle row is made narrower than the groove width of the portion 25a parallel to the nozzle row. In addition, the ink scraped off during the cleaning operation by wiping moves from a portion 25a parallel to the nozzle row to a portion 25b perpendicular to the nozzle row by capillary force, thereby preventing color mixing.

In the second embodiment, the portion perpendicular to the nozzle row is arranged on one side of the nozzle row. However, as shown in the third embodiment of FIG. The grooves 25 may be arranged alternately so as to be arranged on both sides.

In the embodiment of FIGS. 4 and 5, the narrow portion of the groove width perpendicular to the nozzle row is independent for each color. However, as in the fourth embodiment shown in FIG. The same effect can be obtained by using one common groove 35b or by arranging one groove 45b at each end as shown in the fifth embodiment in FIG. In particular, in the case of FIG. 7, since the nozzle rows of each color are surrounded by the grooves and become completely independent, there is no risk of color mixing at the time of wiping, and more excellent effects can be exhibited.

Further, by combining the embodiment of FIGS. 4 to 7 with the embodiment of FIG. 1, the groove width immediately before entering from a portion parallel to the nozzle row to a portion perpendicular to the nozzle row is reduced. It is possible to realize smoother ink movement.

FIG. 8 is a modification of FIG. 4 and shows a state in which a thin groove portion 25c is added. FIG. 9 is a modification of FIG. 5 and shows a state in which a portion 25c having a small groove width is added. FIG. 10 is a modification of FIG. 6, and shows a state in which a portion 35c having a small groove width is added. FIG. 11 is a modified example of FIG. 7 and shows a state in which a portion 45c having a small groove width is added.

In the above-described modification, the capillary force with respect to the central portion can be effectively exerted by reducing the width of the groove immediately before entering from a portion parallel to the nozzle row to a portion perpendicular to the nozzle row. .

In each of the embodiments shown in FIGS.
The width w2 of the wide groove and the width w1 of the narrow groove, and the depth h of these grooves are the same as those described in FIG.

In the modified examples shown in FIGS. 8 to 11, the length L1 of the narrow groove parallel to the nozzle row is the same as the length described in FIG.

Next, a method of manufacturing the above nozzle plate will be described.

As the material of the nozzle plate, SUS304 or SUS316, which is austenitic stainless steel, or nickel is preferable in terms of ink resistance and etching.

When SUS304 or SUS316 is used, a nozzle row is formed on a plate made of these materials with a thickness of 50 to 100 μm by pressing, and then a half-etching is performed with an etching solution made of ferric chloride to form a groove. I do.

When the material of the nozzle plate is nickel, a nickel plate having a thickness of 50 to 100 μm and having a nozzle row is formed by electroforming. Then, such a nickel plate is half-etched with an etching solution composed of ferric chloride to form a groove.

Through the above steps, the nozzle plate of the ink jet print head can be manufactured.

[0037]

As described above, according to the ink jet print head of the present invention, grooves are formed between at least the nozzle rows of a plurality of nozzle rows for discharging different color inks on the nozzle plate, The groove includes a portion having a groove width on which a capillary force acts. The ink collected in the groove is sucked and discharged out of the nozzle plate by the capillary force acting on this portion. Therefore, the ink does not enter the vicinity of the nozzle row of another color, and the color mixture of the ink on the nozzle plate does not occur. Further, even when wiping is repeatedly performed, since no ink is accumulated in the groove, the ink once scraped does not adhere to the nozzle plate again, and the ink ejection direction does not bend or the ejection stops.

As described above, according to the present invention, with an extremely simple structure, it is possible to continuously prevent the color mixture of the ink on the nozzle plate at the time of cleaning at a low cost and to prevent the ink from re-adhering to the nozzle plate. Thus, a decrease in image quality can be suppressed.

[Brief description of the drawings]

FIG. 1 is a front view of a nozzle plate for explaining a first embodiment of an ink jet print head according to the present invention.

FIG. 2 is a diagram showing a state of wiping.

FIG. 3 is a diagram for explaining dimensions of a groove;

FIG. 4 is a front view of a nozzle plate for explaining a second embodiment of the ink jet print head according to the present invention.

FIG. 5 is a front view of a nozzle plate for explaining a third embodiment of the ink jet print head according to the present invention.

FIG. 6 is a front view of a nozzle plate for explaining a fourth embodiment of the ink jet print head according to the present invention.

FIG. 7 is a front view of a nozzle plate for explaining a fifth embodiment of the ink jet print head according to the present invention.

FIG. 8 is a front view of a nozzle plate showing a modification of FIG.

FIG. 9 is a front view of a nozzle plate showing a modification of FIG.

FIG. 10 is a front view of a nozzle plate showing a modification of FIG.

FIG. 11 is a front view of a nozzle plate showing a modification of FIG. 7;

FIG. 12 is a front view of a nozzle plate of an ink jet print head according to a conventional example.

[Explanation of symbols]

 1 Bk nozzle row 2 C nozzle row 3 M nozzle row 4 Y nozzle row 5, 15, 24, 35, 45 Groove 6 Blade 7 Adhered ink 10 Nozzle plate

Claims (8)

(57) [Claims] 1. An ink jet print head in which energy is supplied to ink filled in a plurality of pressure chambers by an energy generating means and ink droplets are ejected from a plurality of nozzles corresponding to the pressure chambers. A groove for collecting ink scraped off by the plate at the time of cleaning is formed between at least the nozzle rows of each color of the plurality of nozzle rows that eject inks of different colors, and the groove extends in parallel to the nozzle row, The width is smaller at the end than at the center, and the end constitutes a portion where the capillary force acts, and the ink accumulated in the center is discharged out of the nozzle plate by the capillary force at the end. An ink jet print head, characterized in that: 2. When the width of the groove at the end is w1, 0.02
5 mm ≦ w1 ≦ 0.1 mm, and the groove width w at the central portion
2. The ink jet print head according to claim 1, wherein 2 satisfies 1.2 × w1 ≦ w2 ≦ 5 × w1. 3. An ink-jet printhead in which energy is supplied to ink filled in a plurality of pressure chambers by an energy generating means and ink droplets are ejected from a plurality of nozzles corresponding to the pressure chambers. A groove for collecting ink scraped off by the plate at the time of cleaning is formed between at least the nozzle rows of each of the plurality of nozzle rows that eject different color inks, and the groove extends in parallel with the nozzle row.
A portion extending at right angles to the nozzle row, and the groove width is
The perpendicularly extending portion is thinner than the parallelly extending portion, and the perpendicularly extending portion constitutes a portion where the capillary force acts. An ink jet print head, wherein the ink is ejected out of a nozzle plate by a capillary force of an extending portion. 4. An ink jet print head in which energy is supplied to ink filled in a plurality of pressure chambers by an energy generating means and ink droplets are ejected from a plurality of nozzles corresponding to the pressure chambers. A groove for collecting ink scraped off by the plate at the time of cleaning is formed between at least the nozzle rows of each color of the plurality of nozzle rows that eject inks of different colors, and the plurality of grooves extend in parallel to the nozzle row. And a single part extending on one side of the nozzle row at a right angle to the nozzle row and connected to the plurality of parts, and the groove width of the part extending at the right angle is larger than that of the parallel extending part. Become thinner, the portion extending at a right angle constitutes a portion on which the capillary force acts, and a plurality of portions extending parallel to the nozzle row An ink jet print head which discharges the accumulated ink to the outside of a nozzle plate by a capillary force of one portion extending perpendicular to the nozzle row. 5. An ink-jet printhead in which energy is supplied to ink filled in a plurality of pressure chambers by an energy generating means and ink droplets are ejected from a plurality of nozzles corresponding to the pressure chambers. A groove for collecting ink scraped off by the plate at the time of cleaning is formed between at least the nozzle rows of each color of the plurality of nozzle rows that eject inks of different colors, and the plurality of grooves extend in parallel to the nozzle row. And two portions that extend at right angles to the nozzle row on both sides of the nozzle row and connect to the plurality of portions, and the groove width of the portion extending at the right angle is greater than that of the parallel extending portion. Are thinned, and the portion extending at right angles constitutes a portion on which the capillary force acts, and a plurality of portions extending in parallel with the nozzle row An ink jet print head which discharges the accumulated ink to the outside of the nozzle plate by the capillary force of two portions extending perpendicular to the nozzle row. 6. When a groove width of a portion extending at right angles to the nozzle row is w1, 0.05 mm ≦ w1 ≦ 0.1 mm, and a groove width w2 of a portion extending parallel to the nozzle row is:
6. The ink jet print head according to claim 3, wherein 1.2.times.w1.ltoreq.w2.ltoreq.5.times.w1. 7. A groove extending parallel to the nozzle row and acting on a capillary force between a portion extending parallel to the nozzle row and a portion extending perpendicular to the nozzle row. An ink jet print head according to claim 3, 4 or 5. 8. The ink jet print head according to claim 1, wherein said plurality of nozzle rows are a black nozzle row, a cyan nozzle row, a magenta nozzle row, and a yellow nozzle row.