JPH04344251A - Printing head for ink jet - 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 to an ink jet print head.

[0002] Inkjet print heads are made of stainless steel plates with ink channels formed by machining, etching, etc.
It is constructed by bonding glass plates, etc. The product trend for inkjet printers using such print heads is toward higher speed and higher density, and the goal of higher density is 300 dpi (dots per inch) to 400 dpi.
It is i.

0003

[Prior Art] For example, in the case of a 300 dpi inkjet print head, the vertical pitch of nozzles is 85 μm.
m, since the nozzle diameter is about 30 to 60 μm, 1
This is impossible to manufacture with heads, and high density can be achieved by arranging two or four rows of heads with large nozzle pitches and arranging the nozzles in each row of heads in a staggered pattern. In this case, conventionally, the nozzle position of each row head is shifted by a predetermined amount from a positioning hole for assembly provided in each row head.

Specifically, in the case of a two-row head configuration, the nozzle pitch of each row is set to 170 μm, and the distance from the positioning hole to the first nozzle is shifted by 85 μm from the first row to each row. By manufacturing a row head and joining it using the positioning hole as a reference, the 85μm
A pitched nozzle arrangement was realized.

FIG. 8 is an exploded perspective view of a conventional inkjet print head 1 having two rows of heads.
1 and 41 are the flow path plate, nozzle plate, and
and diaphragms, 22 , 32 , and 42 are the flow path plate, nozzle plate, and diaphragm of the second row head. Each plate is formed of a thin plate such as a stainless steel plate, and is joined to both sides of the spacer 5 in the illustrated arrangement. 6 and 7 are positioning holes formed at corresponding positions on each plate, and the joining is done through these positioning holes 6 and 7.
7 is the standard.

The nozzle plate 31 is formed with a plurality of nozzles 91 that communicate with the ink passages 81 formed between the passage plate 21 and the nozzle plate 32.
A plurality of nozzles 92 are formed to communicate with the ink flow path 82 formed between the two. Nozzles 91, 92
are the same pitch (170 μm), and the distance from the positioning hole 6 of the head in the first row to the first nozzle 91 and the distance from the positioning hole 6 of the head in the second row to the first nozzle 92 are as described above. There is a difference of 85 μm.

Driving elements 101, 102 such as piezos are attached to the outside of the diaphragms 41, 42 at positions corresponding to the ink channels 81, 82. By driving these drive elements 101 and 102 in a predetermined pattern, pressure is generated in the ink channels 81 and 82 facing the driven drive elements, and the ink channels 8
Ink is ejected from nozzles 91 and 92 communicating with nozzles 1 and 82 to perform recording.

[0008]

However, in the above-mentioned conventional method, since separate members (heads in each row) are joined, there is a problem in that the component precision of the members overlaps and the error in the nozzle pitch increases.

SUMMARY OF THE INVENTION An object of the present invention is to provide an inkjet print head that can improve bonding accuracy and nozzle pitch accuracy without compromising component accuracy.

0010

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a nozzle forming area with a predetermined pitch P1.
a plurality of nozzles arranged in a row, and a pair of positioning holes formed above and below the nozzle forming area, and a distance a from each positioning hole to the nozzle forming area,
The relationship a-b=1/2P1 is set between b.
Two nozzle plates are provided, and two single heads formed using the respective nozzle plates are joined using the positioning holes with one head upside down relative to the other. This is a characteristic configuration (first configuration).

[0011] Also, a predetermined pitch P2 is formed in the nozzle forming area.
a plurality of nozzles arranged in a row, and two pairs of positioning holes, first and second, formed above and below the nozzle forming area; Between the distances c and d to the nozzle formation area and the distances e and f from each positioning hole of the second pair to the nozzle formation area, c-d=1/2P2, f-e=1/ 4
Four nozzle plates (31) having a relationship of P2 are provided, and a
two single heads (29) are joined using the first pair of positioning holes with one upside down relative to the other to form two sub-heads, the two sub-heads comprising:
A configuration (second configuration) characterized in that one of the two is connected vertically with respect to the other using the second pair of positioning holes.

0012

[Operation] In the case of the first configuration, the nozzle of the other single head is located between the nozzles of one single head (a-
b=1/2P1) Therefore, even if P1 is set relatively large, a print head with a small nozzle pitch can be obtained.

In the case of the second configuration, the nozzles of the other subhead are located between the nozzles of one subhead (c-d=1/2P2, fe=1/4P2
Therefore, even if P2 is set relatively large,
A print head with a small nozzle pitch can be obtained.

In any of the above configurations, since the print head is constructed using the same nozzle plate, it is possible to eliminate the problem of overlapping component precision, which has been a problem in the past.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 7.

A first embodiment is shown in FIGS. 1 to 3. This example is for a two-row head.

FIG. 1 is a side view of the nozzle plate of the inkjet print head of this example.
2, and a pair of positioning holes 24 and 25 formed oppositely above and below the nozzle 23 forming area m. . The pitch P1 of the nozzle 23 in the vertical direction (vertical direction in the figure) is 1/150 inch (=170 μm), and m=
It is 1/150 x 25 inches.

Furthermore, the distance a from the nozzle forming area m to the positioning hole 24 (the distance from the lowest nozzle 23 to the positioning hole 24), and the distance a from the nozzle forming area m to the positioning hole 25 (the distance from the lowest nozzle 23 to the positioning hole 25) The distance from the nozzle 23 to the positioning hole 25) is a-b = 1/30.
A relationship of 0 inch (=85 μm) is established. The print head of this example is manufactured using the two nozzle plates 21 having the above configuration, and the procedure will be explained next with reference to FIGS. 2 and 3.

As shown on the left and right sides of FIG. 2, two nozzle plates 2
1 is prepared, and a single head (head member) 29 is formed by stacking a channel plate and a diaphragm on the front and back of each. Note that a pair of positioning holes 24 of the nozzle plate 21 are also provided on the channel plate and the diaphragm.
, 25 are formed to enable later assembly. Next, the nozzle plate 21 of row A on the left
Turn the side upside down as shown by the arrow line in Figure 2, and stack it on the nozzle plate 21 side of row B on the right side with a spacer (positioning holes are formed in the same way as the flow path plate and diaphragm plate). Join together.

During this joining, the positioning holes 24,
Guide pins 26 are inserted into each positioning hole including 25 for positioning. Since the a and b dimensions have the above-mentioned relationship, the nozzles 23 in row B are located between the nozzles 23 in row A as shown in FIG. The nozzle pitch is 1/300 inch. In FIG. 3, 27a is a channel plate, 27b is a diaphragm, and 28 is a spacer. Although not shown, drive elements corresponding to each ink flow path are provided on the surface of each diaphragm 27b, respectively.

[0021] In this way, the print head is formed by inverting one of the two nozzle plates 21, sandwiched between the flow path plate and the vibration plate, and joining them via the spacer. Because it can be configured,
It is possible to avoid overlapping component precision, which has been a problem in the past, and it is possible to ensure the precision of the nozzle pitch in the vertical direction.

A second embodiment is shown in FIGS. 4 to 7. This example is for a 4-row head.

FIG. 4 is a side view of the nozzle plate of the inkjet print head of this example.
2, and two pairs of positioning holes 34, 35 and a positioning hole 36 formed oppositely above and below the nozzle 33 forming area n. , 37. The pitch P2 of the nozzles 33 in the vertical direction (vertical direction in the figure) is 1/75 inch, and n=1/75×12 inch. The arrangement of each positioning hole is as follows.

The relationship c-d=1/150 inch holds between the distance c from the nozzle forming area n to the positioning hole 34 and the distance d from the nozzle forming area n to the positioning hole 35. The distance e from the nozzle formation area n to the positioning hole 36, and the distance e from the nozzle formation area n to the positioning hole 37.
The relationship fe=1/300 inch holds true between the distance f and the distance f. The print head of this example is manufactured by the following procedure using the four nozzle plates 31 having the above configuration.

First, as shown on the left and right sides of FIG. 5, two nozzle plates 31 are prepared and joined using the positioning holes 34 and 35 in the same manner as in the previous example to fabricate a sub-head. 38 is a guide pin for positioning. FIG. 7(A) shows the subhead (head member) produced in this way.
39 is a sectional view of the main parts, 40 is a flow path plate, 41 is a diaphragm, 4
2 is a spacer.

In this joining, since the c and d dimensions have the above relationship, the nozzles 33 in the B row are located between the nozzles 33 in the A row, and the nozzle pitch of the subhead 39 is 1/150 inch. .

Next, two subheads 39 are prepared in the manner described above, and as shown in FIG. 6, they are joined via the head base 43 to form the print head 30. For this joining, one sub-head 39 is turned upside down with respect to the other sub-head 39, and both sub-heads 39 are positioned using the guide pin 44 and the positioning holes 36, 37. As shown in FIG. 7(B), the positioning holes 36 and 37 are inserted into the positioning holes 36 and 37 on the B row side (head base 40 side) of each sub-head 39 to perform positioning. This is the holes 36 and 37 on the A row side and the holes 36 and 3 on the B row side.
This is because the numbers 7 and 7 are out of alignment.

Since the e and f dimensions have the above relationship, the nozzles 33 of one subhead 39 are located between the nozzles 33 of the other subhead 39, and the nozzle pitch of the print head 30 formed by this joining is is 1/300 inch.

[0029]

[Effects of the Invention] As described above, according to the present invention, since the print head is constructed using a plurality of identical nozzle plates, the problem of overlapping parts precision, which has been a problem in the past, can be eliminated. This makes it possible to improve the accuracy of the vertical pitch of the nozzles.

[Brief explanation of drawings]

FIG. 1 is a side view of a nozzle plate of an inkjet print head according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram of a joining procedure for an inkjet print head according to a first embodiment of the present invention.

FIG. 3 is an explanatory diagram of the nozzle arrangement of the print head according to the first embodiment of the present invention.

FIG. 4 is a side view of a nozzle plate of an inkjet print head according to a second embodiment of the present invention.

FIG. 5 is an explanatory diagram of a subhead manufacturing procedure according to a second embodiment of the present invention.

FIG. 6 is an explanatory diagram of a procedure for combining two subheads according to a second embodiment of the present invention.

FIG. 7 is an explanatory diagram of the nozzle arrangement of the subhead and print head of the second embodiment of the present invention, FIG. 7(A) shows the subhead, and FIG. 7(B) shows the print head. There is.

FIG. 8 is an exploded perspective view showing the structure of a conventional inkjet print head.

[Explanation of symbols]

21, 31 Nozzle plate 23, 33 Nozzle 24, 25, 34, 35, 36, 37 Positioning hole 26, 38 Guide pin 28, 42 Spacer 29 Single head (head member) 30 Print head 39 Sub-head (head member) 40 head base

Claims (2)

[Claims] Claim 1: A predetermined pitch P1 in the nozzle forming area.
A plurality of nozzles (23) arranged in a row, and a pair of positioning holes (24) formed above and below the nozzle forming area.
, 25), and between distances a and b from each positioning hole (24, 25) to the nozzle forming area, a-b
Two nozzle plates (2
1), and using the positioning holes (24, 25), two single heads (29) formed using each of the nozzle plates (21) are placed with one head upside down relative to the other. An inkjet print head characterized in that it is constructed by joining. Claim 2: A predetermined pitch P2 in the nozzle forming area.
a plurality of nozzles (33) arranged in a row, and two pairs of positioning holes (33) formed above and below the nozzle forming area.
4, 35), (36, 37), and the distances c, d from one pair of positioning holes (34, 35) to the nozzle forming area and the other pair of positioning holes (36, 37). )
Between the distances e and f from to the nozzle forming area, c-
Two single heads are formed using one nozzle plate (31) by providing four nozzle plates (31) with the relationship of d=1/2P2 and fe=1/4P2. (2
9) are joined using the positioning holes (34, 35) with one upside down relative to the other to form two subheads (39), and the two subheads (39)
An inkjet print head characterized in that the two are joined together using the positioning holes (36, 37) with one side upside down relative to the other.