JPH04366641A - Ink jet printing head - Google Patents

Abstract

PURPOSE:To obtain an ink jet printing head of a simple structure stabilized in ink delivery direction by a method wherein ink guides of a prickle or needle form are disposed in the vicinities of nozzles so as to extend outwards. CONSTITUTION:An ink jet printing head comprises ink chambers 2 capable of pressurizing ink 3 and a nozzle plate 1 provided with nozzles 1a connected to the ink chambers 2. Ink guides 101 of a prickle or needle form are provided in the vicinities of the nozzles 1a so as to extend outwards.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates primarily to printheads used in inkjet printers.

0002

[Prior Art] Inkjet printers eject ink to draw characters and pictures on recording media, and have features such as lower noise than wire dot printers and lower running costs than thermal transfer printers. It is widely used because it holds. However, since inkjet printers have a structure in which ink is ejected from nozzles, there are problems such as the ink ejection state changing depending on the nozzle clogging or the nozzle surface condition, resulting in a decrease in print quality. In particular, subtle conditions around the nozzle and the nozzle, such as variations in nozzle shape, adhesion of foreign matter around the nozzle, and changes in wettability around the nozzle, cause variations in the ejection direction of ink droplets, reducing print quality.

9 and 10 are views showing a conventional inkjet print head, with FIG. 9 being a perspective view and FIG.
FIG. The figure is composed of an ink chamber 2 capable of pressurizing ink 3 and a nozzle plate 1 equipped with a nozzle 1a connected to the ink chamber 2.
The filled ink 3 can be pressurized and ejected from the nozzle 1a to the outside as ink droplets 3d. The four nozzles shown in the figure are connected to respective ink chambers, and ink droplets can be ejected from the required nozzles. The dashed line drawn from the nozzle to the front left in the figure shows the correct flight trajectory of the ink droplets. The ink droplet 3d ejected from the nozzle 1a shown in the first cross section from the front in the figure is ejected in the correct direction, but the shape of the nozzle in the second nozzle from the front in the figure is distorted as shown by the deformed part 601. As a result, the ink droplets ejected deviate from the correct direction shown by the dashed line in the figure and fly in the direction shown by the broken line. Further, the ink droplet ejected from the third nozzle from the front in the figure is influenced by a portion 602 that is more easily wetted by ink than other portions of the nozzle plate surface, and flies in a direction deviated from the correct direction. Further, the ink droplet ejected from the fourth nozzle from the front in the figure is also affected by the foreign matter 603 attached near the nozzle and flies in a direction deviated from the correct direction. FIG. 10 is a cross-sectional view of the conventional print head shown in FIG. 9. When a foreign object 604 is attached near the nozzle 1a, the ink meniscus 3a formed when ink 2 is ejected is As shown in 3b and 3c, the ink droplet 3d grows unevenly and is ejected and flies in a direction deviated from the correct direction. This is considered to be because the ink meniscus is biased toward the foreign object 604 because the ink wettability and ejection resistance increase at the peripheral edge of the nozzle 1a where the foreign object 604 is attached. As described above, in the conventional technique, the ejection direction of ink droplets is highly likely to vary.

Therefore, in conventional inkjet printers, in order to prevent variations in the direction of ink ejection, the nozzles are formed with high precision to keep the nozzle shape constant, and the nozzle periphery is formed by applying a coating to the nozzle plate surface. Countermeasures were required, such as maintaining constant wettability and periodically cleaning the nozzle plate to remove foreign matter from the end of the nozzle. As described above, stabilization of the ink ejection direction has been one of the major issues in conventional inkjet printheads.

[0005]

SUMMARY OF THE INVENTION The present invention was made in view of the various problems encountered in putting such an inkjet print head into practical use, and its purpose is to provide a printing system that is inexpensive and has good print quality. In order to realize
The aim is to enable an inkjet print head with a simple structure and a stable ink ejection direction.

[0006]

[Means for Solving the Problems] That is, in order to solve the above problems, the present invention provides an inkjet print head with a barb-like or needle-like ink guide arranged near the nozzle facing outward.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An inkjet print head according to an embodiment of the present invention will be explained with reference to FIGS. 1 to 8.

FIG. 1 is a perspective view of an ink jet print head according to a first embodiment of the present invention, and FIG. 2 is a cross-sectional view thereof. This embodiment is composed of an ink chamber 2 capable of pressurizing ink 3 and a nozzle plate 1 equipped with a nozzle 1a connected to the ink chamber 2. The ink 3 filled in the ink chamber 2 is When pressed, the ink can be ejected from the nozzle 1a as ink droplets 3d to the outside, and a barb-like or needle-like ink guide 101, which is a feature of the present invention, is formed near the nozzle 1a. Figure 1
The four nozzles indicated by are connected to each ink chamber, and ink droplets can be ejected from the required nozzles. The dashed line drawn from the nozzle to the front left in the figure shows the correct flight trajectory of the ink droplets.

The ink guide 101 is formed beside the nozzle 1a in a direction perpendicular to the nozzle plate 1, or slightly inclined from the perpendicular direction toward the center of the nozzle 1a.
Its shape is thin and pointed at the tip. This ink guide 1
01 as shown in the cross section of FIG. 2, the ink meniscus 3
a, 3b, 3c are nozzles 1 along the ink guide 101.
Since the ink droplet 3d grows in a fixed direction from a, the ink droplet 3d is always ejected and flies in a fixed direction.

According to the present invention, it has been confirmed that even if foreign matter or changes in wettability occur near the nozzle, the ejection direction of the ink droplets hardly changes, and the ink droplets are ejected without deviation from the correct direction. Ta. The ink guide 101 of this embodiment is formed by heating a rod-shaped resin to a semi-molten state.
Weld the end to the nozzle plate and create nozzle plate 1.
The ink guide 101 may be formed as a part of the nozzle plate 1, or the ink guide 101 may be formed as a component. It may be left as is and then adhered or welded to the nozzle plate 1.

FIG. 3 is a perspective view of a second embodiment of the present invention.
FIG. 4 shows its cross section. The basic structure of this embodiment is similar to the first embodiment, in which the pressurized ink 3 in the ink chamber 2 is ejected from the nozzle 1a in which the ink guide 201 is disposed, but this is a feature of the present invention. The arrangement position of the ink guide 201 is different from the first embodiment.

Ink guide 101 used in the first embodiment
was formed perpendicularly from the surface of the nozzle plate 1 beside the nozzle 1a, but the ink guide 20 used in this example
1 is formed not from the surface of the nozzle plate 1 but from the inner wall of the nozzle 1a. With this ink guide, the ink meniscus 3a, 3b, 3c is
The ink droplet 3d grows in a constant direction from inside the nozzle along the ink guide 201, so the ink droplet 3d is always ejected and flies in a constant direction. Although the shape of the ink guide 201 of this embodiment is more complex than that of the ink guide 101 of the first embodiment, it has a greater effect on disturbances such as foreign matter adhering to the vicinity of the nozzle 1a than the first embodiment. It was confirmed that the ejection direction of the ink droplets was highly stable.

FIG. 5 is a perspective view of a third embodiment of the present invention.
FIG. 6 shows its cross section. The basic structure of this embodiment is similar to the first embodiment, in which the pressurized ink 3 in the ink chamber 2 is ejected from the nozzle 1a in which the ink guide 301 is disposed, but this is a feature of the present invention. A plurality of ink guides 301 are arranged around the nozzle 1a. As a result, it was possible to obtain the same effect of stabilizing the ejection direction of ink droplets with a shorter ink guide than in the first embodiment.

FIG. 7 is a perspective view of a fourth embodiment of the present invention.
FIG. 8 shows its cross section. The basic structure of this embodiment is similar to the first embodiment, in which the pressurized ink 3 in the ink chamber 2 is ejected from the nozzle 1a in which the ink guide 401 is disposed.
It is divided into two by 1. It was confirmed that this example has the highest effect of stabilizing the ejection direction of ink droplets compared to the first to third examples.

In the first to third embodiments, the nozzle plate 1 has a planar shape perpendicular to the ink ejection direction, but according to the present invention, the ink guide 401
is arranged in the ink ejection direction, nozzle plate 1
does not necessarily have to be a plane perpendicular to the ink ejection direction. Further, according to the present invention, the effect of stabilizing the ink ejection direction can be obtained regardless of the ink pressurizing means, but the slower the ejection speed, the more the ink ejection direction is stabilized by the ink guide, which is a feature of the present invention. The effect is remarkable.

The inkjet print head according to the present invention is used not only for recording information such as characters and pictures on a recording medium such as paper using ink, but also for printing various types of coatings using liquid droplets, dropping small amounts of liquid, etc. It can also be used to eject selected droplets.

[0017]

According to the present invention, an ink jet print head with a simple structure and a stable ink ejection direction has been made possible.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a first embodiment according to the present invention.

FIG. 2 is a sectional view showing a first embodiment according to the present invention.

FIG. 3 is a perspective view showing a second embodiment according to the present invention.

FIG. 4 is a sectional view showing a second embodiment according to the present invention.

FIG. 5 is a perspective view showing a third embodiment according to the present invention.

FIG. 6 is a sectional view showing a third embodiment of the present invention.

FIG. 7 is a perspective view showing a fourth embodiment according to the present invention.

FIG. 8 is a sectional view showing a fourth embodiment according to the present invention.

FIG. 9 is a perspective view showing a prior art.

FIG. 10 is a sectional view showing a conventional technique.

[Explanation of symbols]

1...Nozzle plate 1a...Nozzle 2... Ink chamber 3...Ink 3a・・・・・・Ink meniscus 3b・・・・・・Ink meniscus 3c...Ink meniscus 3d...Ink droplets 101... Ink guide 201... Ink guide 301・・・Ink guide 401・・・Ink guide 601・・・Deformed part 602... Part that gets wet easily 603...Foreign object 604...Foreign object

Claims (1)

[Claims] 1. An inkjet print head comprising an ink chamber and a nozzle plate having a nozzle connected to the ink chamber and ejecting ink, the ink filled in the ink chamber being pressurized and ejected from the nozzle to the outside. An inkjet print head characterized in that a barb-like or needle-like ink guide is arranged near the nozzle of the nozzle plate.