JPS593150B2 - Inkjet recording device jetting head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ejection head for an on-demand inkjet printing apparatus that performs printing by ejecting ink droplets from desired nozzles in response to input signals.

Conventionally, this type of jet head has been disclosed in U.S. Pat. No. 3,988;
As shown in FIG. 13 of the specification of No. 745, a fan-shaped spray head was created to make the distances from the nozzles to the pressure chambers almost equal, so that the spray conditions from each nozzle were uniform.

However, this structure has a drawback in that forming a large number of pressure chambers on the same substrate increases the size of the ejection head. In order to solve this drawback, the above-mentioned US specification adopts a structure as shown in Fig. 15 by changing the distance from each pressure chamber to the nozzle, but it does not mention anything about making the injection conditions from each nozzle the same. It has not been done.
Furthermore, in Japanese Patent Application Laid-Open No. 52-49032, the distance from the nozzle to the pressure chamber o is kept almost the same, but the shape of the pressure chamber is elongated to prevent the ejection head from increasing in size. Furthermore, a method of aligning the jetting conditions from each nozzle using an electric circuit is also found in Japanese Patent Laid-Open No. 51-55239, but this method has five drawbacks: the circuit becomes complicated. The present invention eliminates the above drawbacks and allows the arrangement of pressure chambers to be set arbitrarily by changing the shape of the flow path from the pressure chamber formed on the substrate to the nozzle without compensating the injection conditions using an electric circuit. The object of the present invention is to provide a multi-nozzle jet head with uniform jet JO conditions.

The present invention will be explained based on the drawings.

In FIG. 1, reference numeral 8 denotes an inflow path through which ink is supplied from an ink tank (not shown), etc.
Send ink to ink 9, which is common to 6.

Each of the pressure chambers 10-16 communicates with the nozzles 24-30 via injection channels 31-3T, respectively. The nozzles 24-30 are normally arranged in such close proximity that ten dots of seven or more can be formed at a height of approximately 0.1 inch for a printed character, and each nozzle 24-30 leads to a pressure chamber 10-30. By arbitrarily changing the lengths of the channels 31 to 3T up to 16, they can be formed on the substrate with good space efficiency so as not to become large. 5. The short channel 31 has a small cross-sectional area, and the long channel 3T has a large cross-sectional area.
The radius or depth of the flow path is changed so that the flow path resistance of 3T is approximately equal.

For example, when the flow path is a circular pipe, in order to keep the flow path resistance constant, the relationship between the flow path length 2 and the flow path radius r becomes a quadratic curve as shown in FIG. As described above, the present invention allows the arrangement of pressure chambers to be set arbitrarily by changing the shape (width, depth, length, etc.) of the flow path from the pressure chamber to the nozzle and making the flow path resistance the same. , the head can be made smaller without increasing its size.

In addition, the jetting conditions from each nozzle can be aligned simply by changing the shape of the flow path without electrical correction of the drive circuit, etc., so the process is almost the same as the conventional head manufacturing process, and the electrical circuit Since there is no complexity, an injection head with a large number of nozzles can be realized at low cost.

[Brief explanation of drawings]

FIG. 1 shows an embodiment of the injection head of the present invention. FIG. 2 is a diagram showing the relationship between the length j and the radius r of the flow path when the flow path is a circular pipe according to the present invention. 10-16...
...Pressure chamber, 24~30...Nozzle, 31~
37...Flow path.

Claims (1)

[Claims] 1. The volume of a plurality of pressure chambers formed on a substrate is rapidly reduced by using deformation of an electro-mechanical conversion element placed opposite to each pressure chamber, and flow paths of different lengths are formed in each pressure chamber. In the ejection head of an inkjet recording device that performs printing by selectively ejecting ink droplets from nozzles that communicate with The jet head of the inkjet recording device is characterized by the passage having a large cross-sectional area.