JPS6222791B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ink-on-demand type ink jet recording apparatus in which a plurality of nozzles are integrated on the same head.

The conventional method will be explained with reference to Fig. 1 A and B.

Figure 1 A is a front view, B is 10 to 1 of A.
0' is a sectional view. Conventional inkjet recording devices include a method in which ink droplets are continuously ejected and the ink droplets are sorted using an electric field, etc., and a method in which ink droplets are ejected only when necessary, but the present invention is based on a method and is suitable for the energy saving era. It is a well-suited and rational device with a simple structure. The ink jet head 1 includes an ink reservoir 2 for uniformly distributing ink to the n pressure chambers 3 and for sending ink to the pressure chamber ink supply port 9 while minimizing disturbance, and an ink reservoir 2 for supplying ink to the ink reservoir. A reservoir ink supply port 7, an ink nozzle 5 for ejecting ink, an ink path 4 for sending ink to the ink nozzle, a pressure chamber 3 for applying ink pressure as a means for ejecting ink from the ink nozzle, and the pressure applying means. It is composed of an air vent 6 for removing air bubbles from an ink path connected to an electrostrictive element 8. The nozzle is normally balanced by normal pressure air and surface tension, but when the pressure chamber 3 is pressurized, the electrostrictive element 8 is distorted by an electric signal. The waves transfer energy and eject ink droplets. At this time, the situation of energy transmission differs depending on the length of the ink path. This is due to factors such as fluid friction caused by the flow of ink, the distance of the ink path, the diameter of the ink path, and manufacturing precision. At the same time, the transmission of pressure waves also differs greatly depending on the shape of the ink path, and even if the pressure of the ink ejected from the nozzle is uniform, the size and ejection speed of ink droplets will differ if the shape of the ink path differs. .

In other words, if there are multiple nozzles, the conditions of the flow path impedance due to the difference in the flow path shape of the integrated head will differ, and the ejection conditions of the ink droplets of the multiple nozzles (ink droplet size and jetting speed) will vary.
It was not possible to print uniformly. Therefore, normal printing is impossible, resulting in a device with poor printing quality and poor alignment of dots. Further, it may be possible to correct the above conditions using an electric circuit or the like, but the electric circuit becomes complicated and the device becomes expensive in terms of cost.

The present invention eliminates the above drawbacks, and even when a plurality of nozzles are formed on a head substrate and the fluid impedance from the nozzle to the pressure chamber is different, ink particles ejected from the plurality of nozzles can cause nozzle variations. The objective is to enable uniform, clear printing without any blemishes.

The inkjet recording device of the present invention includes a pressure applying element mounted on a head substrate, a plurality of nozzles, an ink path communicating with each of the nozzles,
In an ink-on-demand type inkjet recording device in which pressure chambers are arranged and integrated in a plane and the shapes of the plurality of ink paths are not the same, the ink path has a large fluid impedance corresponding to the shape of the ink path. In this case, the size of the pressure chamber communicating with the ink path is increased, and
The present invention is characterized in that the size of the portion of the pressure applying element provided corresponding to the pressure chamber that substantially applies pressure to the pressure chamber is increased.

An embodiment of the inkjet recording apparatus of the present invention will be explained with reference to FIG. Embodiments of the present invention will be described in terms of improvements to conventional methods. The ink jet head 11 includes an ink reservoir ink supply port 7, an ink reservoir 2, an air vent 6, a pressure chamber 3, a pressure chamber ink supply port 9, and a pressure application element 8, as in the conventional system.
The ink passages 41, 42, 43, 44, 45,
Depending on the processing conditions such as the shape of 46 and 47, the pressure chamber 3
Sizes of 1, 32, 33, 34, 35, 36, 37, pressure applying elements 81, 82, 83, 84, 8
5, 86, and 87 are different in shape and size. According to this method, the disadvantage is that the longer the ink path is, the slower the ejection speed of ink particles is due to the difference in the length and shape of the ink paths 41 to 47. If the pressure chambers 31 to 3 are the same, the ink particle diameter becomes small.
7 and the size of the pressure applying elements 81 to 87 that bring about a substantial pressure change in the pressure chamber.
1 to 47 (long ink paths and ink paths with high fluid impedance are both made larger), and the ink ejection speed and ink particle diameter are corrected.
Therefore, from FIG. 2, the device with the longest ink path 44 has the largest pressure chamber 34 and the largest pressure applying element 84.

That is, for nozzles with large fluid impedance, the pressure is increased by increasing the size of the pressure applying element, and differences in print quality such as print dot diameter due to differences in ink path length etc. are equalized. . Therefore, the pressure chamber 34 and the pressure applying element 84 are designed to compensate for the conditions of the ink path 44 so that the speed and shape of the ink particles ejected from the nozzle are determined by the pressure chamber 31 and the pressure applying element 81 of the device with the shortest ink path 41. Printing is performed by correcting the sizes of the pressure applying element 84 and the pressure chamber 34, applying pressure, and ejecting ink particles from the nozzle 5 under the same conditions as the ink particles ejected from the nozzle connected to the pressure chamber 31. Improve accuracy and print quality. Other ink path 4
The same applies to 1 to 47.

In the embodiment shown in FIG. 2 above, if the pressure chambers have the same size, the pressure increases by enlarging the shape of the pressure applying element corresponding to the ink path with large fluid impedance, and the ink jetting conditions become uniform. It is clear that this will be the case.

As described above, according to the present invention, there is a problem that occurs when nozzles, pressure chambers, etc. are integrated on a head, that is, the shape of the ink path that communicates the nozzle and the pressure chamber cannot be made completely the same. This eliminates inconveniences such as uneven print dot sizes, and while forming high-density pressure chambers on the head, it is possible to keep the ink droplet size and ejection speed almost the same, and to obtain good print quality. can. Further, since the pressure chambers and the like are arranged and integrated in a planar manner on the head substrate, the head can be manufactured easily and has additional advantages of high reliability.

[Brief explanation of the drawing]

FIG. 1 shows a conventional embodiment. A is a front view and B is a cross-sectional view. 1... Head, 2... Ink reservoir, 3... Pressure chamber, 4... Ink path, 5... Nozzle, 6... Air vent, 7... Ink reservoir ink supply port, 8... Electrostrictive element, 9 . . . Pressure chamber ink supply port, Fig. 2 is an embodiment of the present invention, 11 .
31-37... Ink pressure chamber, 41-47... Ink path, 81-87...
A pressure applying element.

Claims (1)

[Claims] 1 A pressure applying element is mounted on a head substrate, and a plurality of nozzles, ink passages communicating with the respective nozzles, and pressure chambers are arranged and integrated in a plane, and the shapes of the plurality of ink passages are not the same. In the mand type inkjet recording device, the size of the pressure chamber communicating with the ink path is increased for the ink path having a large fluid impedance corresponding to the shape of the ink path, and the size of the pressure chamber communicating with the ink path is increased. An inkjet recording apparatus characterized in that the size of a portion of the pressure applying element that substantially applies pressure to the pressure chamber is increased.