JPH04151254A - Head assembly body of an ink jet printer - Google Patents

Abstract

PURPOSE: To reduce the size by defining an interval through a ball held on the inside of a pair of head modules thereby eliminating the need of a member, e.g. a holding frame, being disposed on the outside of the head module. CONSTITUTION: A pair of head modules 1 are juxtaposed at a constant interval while facing the channel substrates 3a, 3b each other. A supporting plate 2 is arranged in the gas while being bonded to the substrates 3a, 3b. A ball 13, made of metal or the like, is arranged in a through hole 11 and held in place while abutting against a flat plate 4 through cuts 6a, 6b in substrates 3a, 3b. A protrusion 12 is inserted into holes 7a, 7b, and 9. Adhesive is injected externally into the holes 7a, 7b in order to secure the head modules 1 and the supporting plate 2. Since the ball 13 is secured at a position abutting against the flat plate 4, the interval between the pair of head modules 1 is kept accurately.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a head assembly for an inkjet printer.

[Prior Art] Conventionally, as a head assembly for an inkjet printer, there is one in which a pair of head modules are fixed to both sides of a support plate. In this case, if a shift occurs in the mutual positional relationship of the pair of head modules, the position of the Iraqi nozzle provided in the head module will shift, resulting in a decrease in print quality.

Therefore, the relative positional accuracy between the head modules is improved by sandwiching the head modules with a holding frame from outside, or by performing positioning from the outside using a jig.

[Problems to be Solved] The conventional method described above requires a holding frame in addition to the head module and the support plate, making it difficult to downsize the head assembly. Moreover, since the holding frame must be made of a highly rigid material such as die-cast aluminum, the head assembly becomes large and heavy, and the cost increases. Further, when positioning is performed using a jig, the work of assembling and adjusting the head assembly becomes complicated.

SUMMARY OF THE INVENTION An object of the present invention is to provide a head assembly for an inkjet printer that can easily ensure the positional accuracy of a head module.

[Means for Solving the Problems] A head assembly of an inkjet head printer according to the present invention includes a pair of head modules arranged side by side with a gap and ink nozzles arranged on each front surface, and this pair of heads. It consists of a support plate disposed between the modules. This support plate is provided with a plurality of through holes, and spheres are arranged in each through hole.

The spacing between the two head modules is determined by the sphere coming into contact with both the head modules.

Each head module is composed of a flow path substrate and a flat plate joined to the flow path substrate, and when they are placed side by side with the flow path substrate inside, a notch is formed in the flow path substrate to allow the sphere to abut against the flat plate. Ru.

In addition, when each head module is composed of a flat plate located in the center and a pair of channel substrates bonded to both sides of the flat plate, the inner channel substrate has a notch for making the sphere contact the flat plate. part is formed.

In such a configuration, the ink nozzles are arranged in four rows.

Alternatively, a positioning shaft may be provided upright on the support plate, and the positioning shaft may be fitted into fitting holes provided in both head modules, thereby determining the relative positional relationship between both head modules. can.

[Function] Since the head assembly according to the present invention defines the spacing by the spheres held inside the pair of head modules,
There is no need to provide a member such as a holding frame on the outside of the head module, and miniaturization is possible. Furthermore, since the sphere is fixed at the position where it abuts both head modules, the spacing between the head modules becomes accurate.

Normally, ink channels are formed in the channel substrate by etching or the like, but during etching, planes other than the ink channels are also slightly removed, which may cause errors in thickness. Therefore, errors are likely to occur when positioning the head module based on the flow path substrate. In the present invention, since positioning is performed by bringing the sphere into contact with a flat plate, high precision can be achieved.

[Embodiments] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

1 to 9 show a first embodiment of a head assembly according to the present invention. As shown in FIGS. 1 to 3, the head assembly includes a pair of head modules 1 and a support plate 2 located between them.

First, the head module 1 will be explained with reference to FIGS. 4 to 6. The head module 1 consists of a pair of channel substrates 3a and 3b and a flat plate 4 sandwiched between them. Ink channels (not shown) having nozzles 5a and 5b at their tips are formed on one surface of the channel substrates 3a and 3b, respectively, and on the other surface, an ink channel is formed opposite to the ink channel. Piezoelectric elements 8 are each fixed. In addition, the channel substrates 3a, 3b have four notches 6a, 6b, and a hole 7.
A and 7b are formed at three locations, respectively. The nozzles 5a of the channel substrate 3a and the nozzles 5b of the channel substrate 3b are provided so as to be shifted by half a pitch from each other. That is, the nozzle 5a and one nozzle 5b are connected to the flow path substrates 3a and 3b.
are provided so that they are arranged alternately when they are superimposed. Further, the flat plate 4 is provided with a hole 9 that faces the holes 7a and 7b.

The flow path substrates 3as and 3b having such a configuration are arranged side by side at a constant interval so that the flow path surfaces face each other, and a flat plate 4 is placed in the gap and sandwiched therebetween.

Then, an ink tube 10 for supplying ink from an ink tank (not shown) is fixed to the head module 1.
is configured. Note that the channel substrate 3a.

3b and the flat plate 4 are made of glass, ceramic, or the like.

Next, the support plate 2 will be explained with reference to FIGS. 7 to 9. The support plate 2 has through holes 1 facing the notches 6a and 6b.
1 and a protrusion 12 facing the hole 7a s 7b. Attachment portions 2a, 2bs and 2c for attaching to external members are provided.

As shown in FIGS. 1 to 3, a pair of head modules 1
The channel substrates 3a and 3b are arranged side by side at a constant interval so as to face each other. Then, a support plate 2 is placed in this gap.
are arranged and fixed to the channel substrates 3a and 3b. A sphere 13 made of metal or the like is disposed within the through hole 11, and is held in contact with the flat plate 4 through the cutouts 6a, 6b of the channel substrates 3a, 3b, respectively. Protrusion 12
are inserted into holes 7a, 7b and hole 9. Then, adhesive is injected into the holes 7a and 7b from the outside, and the head module 1 and the support plate 2 are fixed.

This embodiment has the above-mentioned configuration, and the sphere 13 is connected to the flat plate 4.
Since the head modules 1 are fixed at a position where they abut, the distance between the pair of head modules 1 can be maintained with high accuracy.

Normally, ink channels (not shown) are formed in the channel substrates 3a and 3b by etching or other processing, but there is a risk that the flat surfaces other than the ink channels may also be slightly bent during this etching. .

Therefore, if alignment is performed using the channel substrate as a reference, errors are likely to occur. On the other hand, as in this embodiment, the sphere 1
3 in contact with the flat plate 4, high precision can be achieved.

Next, a second embodiment of the present invention will be described.

Descriptions of parts common to those in the first embodiment will be omitted, and they will be denoted by the same reference numerals.

As shown in FIGS. 13 to 15, the channel substrates 3a and 3b have cutouts 6a and 6b in two places, holes 7g and 7b in two places, and fitting holes 14a and 14b in two places, respectively. It is provided. The nozzles 5a and 5b are provided so as to be shifted by a half pitch from each other.

Then, the notch 6a of the channel substrate 3a, the fitting hole 14a,
The notch 6b of the flow path substrate 3b and the fitting hole 14b are formed to be offset from each other by one quarter of the pitch of the nozzles 5a or 5b. The flow path substrate 3a% flat plate 4 and the flow path substrate 3b are stacked to form the head module 1.
5 are configured.

As shown in FIGS. 16 to 18, the support plate 16 is provided with through holes 11 facing the notches 6a and 6b, protrusions 12 facing the holes 7a and 7b, and fitting holes 14a and 14.
A positioning shaft 23 that can be fitted into the portion b is erected on both sides.

As shown in FIGS. 10 to 12, the head modules 15 are arranged side by side at regular intervals with the channel substrates 3 a s 3 b facing inward. The support plate 16 is placed in this gap.
is installed. A sphere 13 is disposed within the through hole 11, and is held in contact with the flat plate 4 through the cutouts 6a and 6b. The protrusion 12 is inserted into the holes 7a, 7b and the hole 9. The positioning shaft 23 is in the fitting hole 14a
, 14b and is in contact with the flat plate 4,
Unable to move. Adhesive is injected into the holes 7a and 7b from the outside, and the head module 15 and support plate 16 are fixed.

The height from one end of the positioning shaft 23 to the other end is the height of the sphere 13.
is formed equal to the diameter of the sphere 13 and the shaft 23
Since the head modules 15 are fixed at positions where they contact the flat plate 4, the pair of head modules 15 are fixed with good positional accuracy in the thickness direction and with good parallelism. Furthermore, since the positioning shaft 23 is immovably fitted into the fitting hole 14, positioning can be performed with high accuracy in the left-right direction in FIG. In addition, the channel substrate 3
a, 3b, the notches 6a, 6b and the fitting hole 14
a and 14b are formed to be shifted by 1/4 of the nozzle pitch, so the positioning shaft 23 and the sphere 13 allow the pair of head modules 15 to be spaced apart from each other by 4 of the nozzle pitch.
It is positioned and fixed so as to shift by a factor of 1. Since the nozzles 5a and 5b are offset by a half pitch from each other, the head assembly is constructed such that the nozzles are located at a quarter pitch interval. In this way, in this embodiment, the notches 6a, 6b and the fitting hole 14a
, 14b is a quarter of the pitch of the nozzle 5a or 5b
Since the head modules are formed so as to be shifted by the same amount, there is no need to fix two different types of head modules to both sides of the support plate, and two identical head modules 15 can be used to connect the flow path substrate 3a.
The above-mentioned head assembly is constructed by fixing the support plate so that the support plates 3b and 3b face each other. Therefore, the manufacturing process can be simplified and costs can be reduced.

In the above two embodiments, the head module 1.15
1 has a structure in which flow path substrates 3a13b are joined to both sides of a flat plate 4, and is composed of either ink nozzles or a head assembly arranged in four rows, but is not limited to this. 19th
As shown in the third embodiment, a head module 17a in which a flow path substrate 3a and a flat plate 4 are fixed, and a head module 17b in which a flow path 3b and a flat plate 4 are fixed are used, and a support plate 2 is placed between them. It is also possible to have a configuration in which it is arranged. In this case as well, with the sphere 13 disposed in the through hole 11 of the support plate 2 in contact with the flat plate 4 via the notches 6a and 6b of the channel substrates 3a and 3b, the he/sodo module 17a, 17b is fixed. Therefore, both head modules 17a, 17b
The spacing between will be accurate.

In the fourth embodiment shown in FIG. 20, a flat plate 4 is fixed to flow path substrates 18a and 18b which are not provided with cutouts, and head modules 19a and 19b are constructed.

Then, turn the head module 19a with the flat plate 4 facing inward.
, 19b are arranged side by side, and the support plate 2 is positioned in the gap between them. Sphere 20 arranged in through hole 11a of support plate 2
is in contact with the flat plate 4, the head module 17as
17b is fixed. In this case, the sphere 20 has a smaller diameter than the sphere 13, and the through hole 11a is also formed correspondingly smaller.

In the fifth embodiment shown in FIG. 21, ink channels (not shown) are formed on both the front and back surfaces of the channel substrate 21. The tip of this ink flow path is the nozzle 5c.

It has become 5d. Then, flat plates 4 are fixed to both sides of the channel substrate 21, respectively, to constitute a head module 22. A pair of head modules 22 are arranged side by side at a constant interval, and the support plate 2 is positioned in the gap. Sphere 2 arranged in through hole 11a of support plate 2
The pair of head modules 22 are fixed in a state where the head modules 0 are in contact with the flat plate 4.

In this way, by fixing the pair of hesodomonules with the spheres in contact with the flat plate, a highly accurate head assembly can be easily manufactured. Further, there is no need to use a holding frame or a jig, the number of parts can be reduced, the size can be reduced, and the assembly and position adjustment processes can be simplified.

Furthermore, since it can be manufactured from ceramic, glass, etc., it can be made lighter.

[Effects] As described above, according to the present invention, an inkjet printer head assembly with good positional accuracy can be easily manufactured. Furthermore, the number of parts can be reduced, the configuration can be simplified, and the size can be reduced.

[Brief explanation of drawings]

1 to 9 show a first embodiment of the present invention, in which FIG. 1 is a plan view with one head module removed from the head assembly, FIG. 2 is a front view of the head assembly, and FIG. The figure is a rear view of the head module, Figure 4 is a plan view of the head module, and Figure 5 is a top view of the head module.
The figure is its front view, Figure 6 is its rear view, Figure 7 is a plan view of the support plate, Figure 8 is its front view, and Figure 9 is its rear view.
Figures 10 to 18 show the second embodiment, with Figure 10 being a plan view with one head module removed from the head assembly, Figure 11 being a front view of the head assembly, and Figure 12 being the same. Rear view, Figure 13 is a plan view of the spatula lower module,
Figure 14 is its front view, Figure 15 is its rear view, and Figure 16 is its front view.
The figure is a plan view of the support plate, FIG. 17 is a front view thereof, FIG. 18 is a rear view thereof, FIG. 19 is a front view of the third embodiment, and FIG.
0 is a front view of the fourth embodiment, and FIG. 21 is a front view of the fifth embodiment. 1.15.17a, 17b, 19a. 19b, 22...Head module, 2.16...
...Support plate, 3a, 3b, 18a, 18b, 21...Flow path substrate, 4...Flat plate, 5a, 5b, 5c, 5d---Nozzle, 6a, 6b・
...notch, 11.11a...through hole, 13.20...sphere, 14a, 14b..."fitting hole, two positioning shafts, and more

Claims (4)

[Claims] (1) a pair of head modules arranged side by side with an interval and having ink nozzles arranged at a predetermined pitch on each front surface; a support plate disposed between the pair of head modules and having a plurality of through holes; A head assembly for an inkjet printer, comprising: spheres disposed in respective through holes and defining the distance between the two head modules. (2) Each head module is composed of a flow path substrate and a flat plate joined to the flow path substrate, and is arranged side by side with the flow path substrate inside, and the sphere is placed on the flow path substrate. 2. The head assembly for an inkjet printer according to claim 1, further comprising a notch for directly contacting the flat plate. (3) Each head module consists of a flat plate located in the center and a pair of flow path substrates bonded to both sides of the flat plate. 2. The head assembly for an inkjet printer according to claim 1, further comprising a notch for contacting the head assembly. (4) The head module is provided with a plurality of fitting holes, and the support plate is provided with positioning that fits into each of the fitting holes to determine the relative positional relationship of the pair of head modules. 4. The head assembly for an inkjet printer according to claim 1, further comprising a shaft.