JPH04366642A - Ink jet printing head - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

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.

FIG. 3 is a perspective view of a conventional ink-jet print head, showing a cross section on the right side of the figure. The inkjet print head shown in 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 ink 3 filled in the ink chamber 2 is Nozzle 1a is pressurized
The ink droplet 3d can be ejected from the ink droplet 3d to the outside. 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 droplet. 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. Furthermore, 4 from the front in the diagram
The ink droplets ejected from the th nozzle are also affected by the foreign matter 603 attached near the nozzle and fly in a direction deviated from the correct direction. FIG. 4 is a cross-sectional view of the conventional print head shown in FIG. 3. When a foreign object 604 is attached near the nozzle 1a, the ink meniscus 3a formed when the 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 ink jet print head in which a plurality of needles or bristles facing in the ink ejection direction are arranged on a surface near the nozzles.

[0007]

[Operation] By arranging a plurality of needles or hairs facing in the ink ejection direction on the surface near the nozzles of the ink jet print head, it is possible to stabilize the ink ejection direction.

[0008]

EXAMPLE An inkjet print head produced as an example of the present invention will be explained with reference to FIGS. 1 and 2.

FIG. 1 is a perspective view of an ink jet print head manufactured as an 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 pressurized. Nozzle 1a
The ink droplets 3d are ejected from the nozzle 1a to the outside.
A plurality of bristles 101 facing in the ink ejection direction, which is a feature of the present invention, are formed on the surface near the ink. The four nozzles shown in FIG. 1 are connected to respective ink chambers, and ink droplets can be ejected from the required nozzles.

[0010] In the figure, a dashed line drawn from the nozzle 1a to the left front shows the correct flight trajectory of the ink droplet. The bristles 101 are formed on the nozzle 1a in a direction substantially perpendicular to the nozzle plate 1. As shown in the cross section of FIG.
Since the ink droplet 3d grows in a fixed direction from the nozzle 1a along a plurality of surrounding bristles 101, the ink droplet 3d is always ejected and flies in a fixed direction.

According to the present invention, it is possible to prevent foreign matter from adhering to the vicinity of the nozzle 1a as in the prior art, and even when the wettability of the nozzle plate 1 changes, the action of the plurality of hairs Since the ink does not come into contact with the surface of the nozzle plate 1, ink droplets are ejected with almost no deviation from the correct direction. To form the bristles 101 in this embodiment, the nozzle plate 1 with adhesive applied to the part where the bristles 101 are to be formed is arranged in parallel above a flat plate electrode on which a plurality of bristles 101 are placed, and the nozzle plate 1 and the flat plate This was done by applying a high voltage between the electrodes to charge the bristles 101, and then drawing them perpendicularly to the nozzle plate 1 and adhering them. The arrangement density of the bristles 101 is preferably at least five or more per the opening area of the nozzle 1a, and the bristles 101 are desirably made of a material that is difficult to wet with the ink 3.

The bristles 101 used in this example were made of resin that is difficult to wet with the ink 3;
In order to further worsen the wettability with the material, a material woven with a plurality of fine fibers may be used. The same effect can also be obtained by using needles that are stiffer than hair.

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.

[0014]

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 an embodiment according to the present invention.

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

FIG. 3 is a perspective view showing a prior art.

FIG. 4 is a sectional view showing a prior art.

[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... hair 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 connected to the ink chamber and having nozzles for ejecting ink, the ink filled in the ink chamber being pressurized and ejected from the nozzles to the outside. . An inkjet print head, characterized in that a plurality of needles or bristles facing in the ink ejection direction are arranged on a surface of the nozzle plate near the nozzle.