JPH0341073B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to the structure of a multi-nozzle ink jet head, and particularly to an ink jet head in which dots formed by ink ejected from nozzles do not shift in position. Regarding the nozzle arrangement structure.

A voltage is applied to the piezoelectric element installed above the pressure chamber containing the print recording ink to distort it based on the print information, and the pressure caused by this distortion is transmitted to the pressure chamber and communicated with the pressure chamber. An inkjet recording method is well known in which printing ink is jetted onto a recording paper from a nozzle provided at one end of the recording paper.

This inkjet head recording method is a non-impact recording method, generates little noise during print recording, has good print quality, and has a simple structure, so it has recently been used as an output device for electronic computers. It is becoming widely used.

Inkjet head nozzles like this,
When ink is ejected onto recording paper from the nozzles of a multi-nozzle ink jet head to form printed dots, it is highly possible that the relative positions of the ink ejected from each nozzle will not deviate. This is required to achieve reliable printing.

[Conventional technology]

The conventional structure of such an inkjet head is shown in the plan view of FIG.
This will be explained using the cross-sectional view of FIG. 6 taken along line B' and the cross-sectional view of FIG. 7 taken along line D-D' of FIG.

In FIG. 5, 1 is a nozzle for ejecting ink, 2 is a pressure chamber that accommodates ink and transmits pressure from a piezoelectric element 3, and 4 is an ink conductor that connects pressure chamber 2 and nozzle 1. A passageway, 5 is a common ink chamber that temporarily stores ink, 6 is an ink supply path that connects the pressure chamber 2 and the common ink chamber 5, and 7 is a channel that supplies ink to the common ink chamber 5 from an ink tank (not shown). This is an ink supply tube for.

As shown in FIG. 7, ink passages such as the nozzle 1, ink conduction passage 4, pressure chamber 2, ink supply passage 6, and common ink chamber 5 are connected to an ink passage plate 8A made of a thin plate made of stainless steel, 8B is etched to a certain depth, and only the nozzle is half-etched to a depth of approximately 1/2 of the certain depth, and piezoelectric elements 3 are formed on the ink channel plates 8A and 8B. A diaphragm 9 made of a thin stainless steel plate to which the piezoelectric element 3 is fixed and transmits the pressure from the piezoelectric element 3.
A and 9B are joined by a brazing method or the like.

Nozzle hole 1 of such an inkjet head
As shown in FIG. 6, the nozzles 1 are formed in a line on the ink flow path plate 8A with a predetermined pitch L apart, and the nozzles 1 arranged on the ink flow path plate 8A are
Nozzles 1 are formed alternately on the ink flow path plates 8B corresponding to the ink flow path plates 8B, and the cross-sectional shape of the nozzles formed on the ink flow path plates 8A and 8B is a semicircle obtained by cutting a circle with a straight line. The semicircular arc of this cross section has a corresponding structure.

The above-mentioned ink passage is constructed of two layers of thin plates using etching means, but it is also possible to construct the ink passages of three layers as shown in FIGS. 1 to 3, which will be described later.

FIG. 8 shows the arrangement of the nozzles obtained by moving FIG. 6 by 90 degrees along the direction of arrow B, and FIG. 2 is a plan view of a state in which printing is performed while ejecting ink from a nozzle.

In FIG. 9, the recording paper 11 moves in a direction perpendicular to this plan view, the nozzle surface 10 moves in the X direction, and after the nozzle rows 12 of the nozzle surface 10 eject ink to form printed dots. , printing dots are formed by the nozzle row 13 filling the spaces between the printing dots formed by the nozzle row 12.

[Problem that the invention seeks to solve]

By the way, if you enlarge the cross-sectional shape of nozzle 1, the first
As shown in Figure 0, the cross section of the nozzle 1 is vertically symmetrical with respect to the x-axis passing through the center O of the cross section, but is not horizontally symmetrical with respect to the y-axis passing through the center O. do not have. When conducting a print recording experiment by ejecting ink onto recording paper from such a nozzle,
The ink tends to be displaced in the direction of the semicircular straight line in the cross section of the nozzle 1 and fly, so the arc-shaped parts of the nozzle 1 are arranged so as to face each other, as shown in Fig. 8. On the nozzle surface 10, the ninth
As shown in the figure, the flying direction of this ink is displaced by an angle θ, or by a distance l if expressed as a distance.

Therefore, when printing dots are formed on recording paper with an inkjet head having such a nozzle surface 10, the distance l of the positional deviation from the predetermined position of the printing dots 14 formed by the first nozzle row 12 is , the distance l of the positional deviation from the predetermined position of the printed dot 15 formed by the second nozzle row 13
overlap, and the distance of positional deviation between these printing dots 14 and 15 is amplified to 2L, and there is a problem that high-quality printing cannot be achieved when printing is performed using such printing dots. .

[Means for solving problems]

The above-mentioned problem consists of a plurality of nozzle rows in which a large number of nozzle holes having a semicircular cross section are arranged at a predetermined pitch, and each nozzle is arranged in a staggered manner. This problem is solved by the ink jet head of the present invention, in which the arcuate sides of the cross sections of the nozzle holes are all arranged in the same direction.

[Effect]

That is, in the ink jet head of the present invention, a plurality of nozzle rows are provided in which nozzle holes having a semicircular cross-sectional shape are arranged at a predetermined pitch so that the pitches of the nozzle holes are alternated. The arcuate sides of the cross sections of the inkjet heads are arranged so that they face the same direction, so that even if the ink is displaced in the flying direction, the displacement is in the same direction with respect to the traveling direction of the ink jet head relative to the recording paper. 1
This eliminates variations in the distance of positional deviation between the printed dots formed by the first nozzle row and the printed dots formed by the second nozzle row.

〔Example〕

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

1 is a cross-sectional view of the ink jet head of the present invention, FIG. 2 is a cross-sectional view showing the nozzle structure taken along line A-A' in FIG. 1, and FIG. This is a cross-sectional view rotated 90 degrees in the direction of arrow B.
This figure shows a state in which a nozzle surface having the nozzle structure shown in FIG. 3 is arranged to face a recording paper to form printed dots.

As shown in FIGS. 1, 2, and 3, in the ink jet head of the present invention, only the first row of nozzle holes 21A have a depth of about 1/2, which corresponds to the thickness of the ink channel plate 26. Half-etching is performed to a thickness of
3. An ink channel plate 26 made of a thin stainless steel plate in which ink channels such as the ink supply channel 24 and the common ink chamber 25 are formed by etching.
and a diaphragm 28 made of a thin stainless steel plate to which the piezoelectric element 27 is fixed. Separately, only the nozzle holes 21B in the second row are half-etched to a certain depth corresponding to the thickness of the ink channel plate 29 (same as the thickness of the ink channel plate 26), and other ink For the passage, a diaphragm 31 made of a thin plate made of stainless steel to which an ink flow path plate 29 and a piezoelectric element 30 are fixed is prepared in the same manner as described above. Separately from this, a stainless steel bottom plate 32 is provided with an etched opening for the common ink chamber 25.
are prepared, and the ink flow path plates 26, 29, diaphragms 28, 31, and bottom plate 32 are joined by soldering to form an ink jet head. Figure 2,
And as shown in FIG. 3, the first row of nozzles 21A formed on the ink passage plate 26 of the nozzle surface 33 of the ink jet head thus formed.
The nozzles 2 of the second row are formed at a predetermined pitch L and are formed on the ink flow path plate 29.
1B is the nozzle 2 in the first row across the pitch L.
They are arranged at alternate positions with respect to the arrangement of 1A. Also, the semicircular arc portion of the cross section of the nozzles 21A in the first row and the semicircular arc portion of the cross section of the nozzles 21B in the second row are such that the nozzle surface 33 moves relative to the recording paper. 3, that is, the direction of arrow C in FIG.

As shown in FIG. 4, the nozzle surface 33 of the inkjet head of the present invention having such nozzles is placed facing the recording paper 34, and the nozzle surface 33 is moved in the direction of arrow C. When printing is performed while moving in a direction perpendicular to this drawing, from nozzle 21A and nozzle 21B,
Ink 35A, 35B jetted onto recording paper 34
is an angle θ from a predetermined position to the side cut by the semicircular straight section of the cross section of nozzle 21A and nozzle 21B.
Displaced by 100 cm and fly.

Therefore, printed dots 36A and 36B are formed on the recording paper 34 by the nozzle 21A and the nozzle 21B.
are formed by being displaced by a distance l from their respective predetermined positions, but since these displaced distances are all in the same direction, the printed dots 36A and 36A formed by the nozzles 21A in the first row , second
Print dots 36 formed by the row nozzles 21B
No relative positional shift with respect to B occurs.

Therefore, if printing is performed using an ink jet head having such a nozzle surface of the present invention,
Since the relative position between the printed dots printed by each nozzle row does not shift, there is an effect that high quality print recording can be performed.

Further, in this embodiment, the case where there are two nozzle rows has been described, but of course there may be two or more nozzle rows.

〔Effect of the invention〕

As described above, if printing is performed using an inkjet head having a nozzle surface with the nozzle array structure of the present invention, there is no relative positional deviation of printed dots, so high-quality printing can be performed. effective.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the ink jet head of the present invention, FIG. 2 is a plan view of the nozzle surface of the ink jet head of the present invention, and FIG. 3 is 90 degrees from FIG. 2 in the direction of arrow B. FIG. 4 is a plan view of the rotating nozzle surface, FIG. 4 is a schematic diagram showing the state when printing is performed on recording paper using the ink jet head of the present invention, and FIG. 5 is a plan view showing the structure of a conventional ink jet head. Figure 6 is a cross-sectional view of Figure 5 taken along line B-B', and Figure 7 is a cross-sectional view of Figure 5 taken along line D-B'.
8 is a sectional view taken along line D', FIG. 8 is a plan view of the nozzle surface of a conventional ink jet head, and FIG.
The figure is a schematic view showing the state of printing and recording using a conventional ink jet head, and FIG. 10 is an enlarged view of the nozzle holes of the conventional ink jet head. In the figure, 21A and 21B are nozzles, 22 is a pressure chamber, 23 is an ink conduction path, 24 is an ink supply path, 25 is a common ink chamber, 26 and 29 are ink channel plates, 27 and 30 are piezoelectric elements, 28 and 31 are diaphragms, 32 is a bottom plate, 33 is a nozzle surface, 34 is a recording paper, 35A and 35B are ink, 36A and 36B are printed dots, B is an arrow indicating the direction of rotation of the nozzle surface, and C is nozzle movement. The arrow indicates the direction, L indicates the pitch between the nozzles, and l indicates the displacement distance of the printed dots.

Claims (1)

[Scope of Claims] 1. A plurality of nozzle rows each having a plurality of nozzle holes each having a semicircular cross section arranged at a predetermined pitch so that each nozzle is staggered;
An ink jet head for jetting ink onto a recording paper from each nozzle for recording, wherein the arc sides of the cross sections of the nozzle holes are all arranged in the same direction.