JPS59198162A - inkjet recording 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 Technical Field of the Invention The present invention relates to an inkjet recording head, and particularly relates to an inkjet recording head having multiple nozzles capable of halftone recording.

(b) Prior art and problems In the recording heads of conventional inkjet recording devices, in order to perform halftone recording (expressing light and shade of color), a method (dithering) of recording dots in a fixed 71-linox size with varying numbers of dots is used. However, the disadvantage of this method is that the pixels are large and the resolution is not high.

There is also a method of changing the diameter of the ejected ink particles by changing the drive pulse conditions of the piezoelectric element, but there is a limit to the range in which the particle diameter can be varied with only these drive pulse conditions, and the difference between floors is small. This is a drawback.

On the other hand, halftones can be obtained by using inks with different densities, but conventionally, using multiple types of ink means arranging multiple recording holes 1' in parallel, which requires complicated combing. Therefore, there is a problem that alignment with a high degree of M cannot be performed.

(C) Object of the Invention The present invention provides a method for inkjet recording in which halftones can be easily obtained without using the method with such drawbacks and problems.

fd) Structure of the Invention The object of the invention is to provide an ink chamber comprising an ink chamber, a pressure chamber communicating with the ink chamber, a nozzle communicating with the pressure chamber, and a piezoelectric element forming at least a part of a side wall of the pressure chamber. , an on-demand inkjet recording head that ejects ink particles from a nozzle by driving the piezoelectric element, which includes a plurality of ink chambers storing ink of different concentrations, and a plurality of nozzles electrically connected to each ink chamber. This is achieved by an inkjet recording head with

+6+ Examples of the invention Examples will be described in detail below with reference to nine drawings.

Inkjet recording heads need to be made extremely finely and precisely.For example, the nozzle diameter is precisely machined to around several tens of micrometers, and the conduction paths and pressure chambers also require high precision, so they are made by etching a thin metal plate. BACKGROUND ART A method for manufacturing a laminated structure of multilayer plates is known.

Figures 1 (al), (bl and 2) illustrate a conventional recording head with a plurality of nozzles using such a multilayer plate stacking method (HJHk), and Figure 1 (c) is a cross-sectional view of 11. , No. 1(b) is a side view, and FIG. 2 is a diagram of part 11i of (.).A recording head with such a multi-hole structure is designed to increase the recording speed. Since the internal structure of a multi-nozzle becomes more complicated, a multi-layer laminated structure in which pressure plates are laminated is particularly desired, and most of them are manufactured using a laminated structure method. Element 2
The ink supply port 3 and nozzle 4 are exposed, but the inside is the ink chamber 5, as shown in the cross-sectional view of FIG. The pressure chamber 6 and the electrical connection [I! 87 are provided in a converging manner, and the shape is complicated with a plurality of them mixed together, so a laminated structure is suitable. Note that the nozzle 4 is generally formed by drilling a hole in the nozzle plate 4P.

However, the above example is a multi-nozzle recording head for high-speed recording, and therefore only one ink chamber and one ink supply port are used.
By simply driving a desired piezoelectric element, ink of the same density is ejected from a desired nozzle for recording. The present invention utilizes such a multilayer board laminated structure to provide a plurality of ink chambers and ink supply ports, and supplies ink of different density to each ink chamber so that halftone recording can be obtained. This is what I did.

Fig. 3 fan, (bl) and Fig. 4 show an embodiment of the recording head for halftone recording according to the present invention;
Fig. fa) is a plan view, Fig. 3) is a side view, and Fig. 4 is a partial sectional view thereof. As shown, four ink chambers 51
．． 52, 53, and 54 are provided, and inks of different densities, that is, inks of light to dark densities, are sequentially supplied to the ink chambers 51 to 54 from the ink supply paths 31, 32, 33, and 34 to the respective ink chambers, and Each pressure chamber6. Nozzles 41 to 4 of the same diameter conduct through the conduction path and eject.
4 are arranged in parallel in the moving direction of the head (in the direction of the arrow shown in FIG. 3). In addition, the nozzles in the vertical direction are connected to ink chambers having the same density, so that this example serves as a print head that prints one row of pixels.

A recording head having such a structure can perform halftone recording by selecting a piezoelectric element based on an image signal and ejecting ink droplets of different gradation levels.

In addition, with such a multi-layered structure, even if multiple ink chambers are formed, the manufacturing method of etching thin metal plates and laminating them is no different from the conventional multi-layered structure and the creation method. , can be created easily as well.

(fl Effects of the Invention The above is just one embodiment, but unlike the conventional method of creating a plurality of recording heads and combining them in parallel, the present invention has a single head structure and prints a plurality of inks of different densities. Since it is a method of ejecting and recording, it is possible to eject with high precision and obtain clear records.

Therefore, according to the present invention, accurate halftone recorded images and characters can be recorded clearly.

[Brief explanation of the drawing]

FIG. 1 (al, fh) is a plan view and side view of a conventional inkjet recording head with multi-nozzles, FIG. 2 is a partial sectional view thereof, and FIG. 3+8>, fb) is an inkjet recording head according to the present invention. A plan view and a side view of one embodiment of the head, and FIG. 4 is a partial sectional view thereof. In the figure, 1 is the head body, 2 is the piezoelectric element, 3°31.32
．． 33.34 is an ink supply path, 4°41.42,43.
41 is a nozzle, 5, 51, 52, 53, and 54 are ink chambers, 6 is a pressure chamber, and 7 is a conduction path. Figure 1 (C1) (b) Figure 2

Claims (1)

[Claims] It has an ink chamber, a pressure chamber communicating with the ink chamber, a nozzle communicating with the pressure chamber, and a piezoelectric element forming at least a part of a side wall of the pressure chamber, and the nozzle is activated by driving the piezoelectric element. 1. An on-demand inkjet recording head that ejects ink particles from an inkjet recording head, characterized by having a plurality of ink chambers storing ink of different concentrations and a plurality of nozzles connected to each ink chamber corresponding to the ink chambers. To 7 do.