JP3520436B2 - Ink jet recording head unit and ink jet recording head - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention provides a pressure generating means in a partial region of a pressure generating chamber communicating with a nozzle opening,
The present invention relates to an inkjet recording head in which a plurality of head units that pressurize ink in a pressure generating chamber to generate ink droplets are arranged in a row, and more specifically, to a wiring structure for supplying a drive signal to each head unit.

[0002]

2. Description of the Related Art In order to support high-speed printing and high-density printing, it has been attempted to increase the number of nozzle openings per recording head, but an ink jet recording head handles a liquid called ink. Therefore, it is required to form a large number of nozzle openings and pressure generation chambers uniformly and with high accuracy, because they are sensitive to the influence of non-uniformity such as fluid resistance of the flow passages such as nozzle openings and pressure generation chambers. Moreover, if a defect occurs even in one of the flow passages and the pressure generating means, the printing quality is extremely deteriorated and it becomes useless as a recording head. Therefore, the manufacturing yield is considerably higher than that of other recording heads. It has the problem of being low.

In order to solve such a problem, a recording head having a relatively small number of nozzles is formed, and a plurality of recording head units are fixed to one substrate to form one recording head. However, since the thickness of the wall of the adjacent unit is equal to or greater than the arrangement pitch of the nozzle openings, it is necessary to shift the width of one unit in a zigzag manner, and the width of the recording head is 2 times the width of the unit. There is a problem that it becomes twice as large.

In order to solve such a problem, the present applicant has previously proposed that a plurality of pressure generating chambers 61 for pressurizing ink by the pressure generating means are arranged in the arrangement direction of the nozzle openings 62 as shown in FIG. And the side walls 63 on the upper and lower ends of the nozzle openings 62 are inclined by an angle α in the arrangement direction of the nozzle openings 62, and the side walls 65 on both sides are arranged in the arrangement direction of the nozzle openings 62. A plurality of head units 66 configured to be parallel to the fixed substrate 6
We proposed a recording head arranged in No. 7.

According to this, since the wall surfaces 63 where the head units face each other are inclined, when the head units 66 are displaced parallel to each other along the wall surface 63, the pitch is less than the pitch of the nozzle openings 62 of the head units 66 facing each other. It is possible to adjust, the offset amount ΔS of the head unit 66 in the width direction can be reduced, and a recording head having a relatively small width can be configured.

[0006]

However, due to the offset existing between the units, a step is generated between the units, and the alignment between the connection terminal portions arranged on both sides of the recording head unit and the connection terminal portions of the flexible cable is performed. There is an inconvenience that an error is likely to occur and connection of the flexible cable becomes difficult. The present invention has been made in view of such circumstances, and an object of the present invention is to provide a recording head unit capable of accurately positioning a connecting portion of a flexible cable. Another object of the present invention is to provide a recording head using a plurality of the recording head units.

[0007]

In order to solve such a problem, in the present invention, nozzle openings for ejecting ink droplets are arranged in a plurality of rows to form a nozzle opening row.
In addition, a predetermined angle α with respect to the arrangement direction of the nozzle openings
A pressure generating chamber which is arranged to be inclined with respect to the nozzle opening and communicates with the nozzle opening; pressure generating means for pressurizing the pressure generating chamber; and an electrode of the pressure generating means and a conductive means for connection to the pressure generating means. and a connection terminal portion for supplying, first
In a rectangular recording head unit having four sidewalls from 1 to 4, the recording head unit includes the nozzle.
A plurality of recording lines are arranged in the direction of the arrangement line of the openings.
Said first partitioning between adjacent head unit, comprising an angle α second sidewall relative to the arrangement direction of the nozzle openings, 且
The third and fourth side walls that intersect the first and second side walls are angled with respect to the direction of the alignment line of the nozzle openings.
Degree θ, across the adjacent recording head units
The arrangement pitch of the nozzle openings is the same,
On one recording head unit of the adjacent head unit
Nozzle opening array line and other recording head unit
The nozzle opening array line in is the array of the nozzle openings
Formed with a deviation in the direction perpendicular to the line
It

[0008]

When a plurality of head units are arranged, the entire side walls are aligned and the connecting terminals are positioned perpendicularly to the side walls. It is possible to position the recording head unit by aligning it with the side wall of the recording head unit simply by forming the shape.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The details of the present invention will be described below with reference to illustrated embodiments. 1 and 2 are views showing an embodiment of an ink jet type recording head using a recording head unit of the present invention, with a flexible cable removed, and a schematic diagram of a cable for supplying a drive signal. In the drawings, reference numerals 1, 1, and 1 are recording head units having the same structure and characterized by the present invention. Each unit has outer side walls 2, 3, 4, and 5 of a parallelogram. It is formed so as to.

In the central region of each unit 1, 1, 1 there are two nozzle openings 6, 7 arranged in parallel with each other so as to have an inclination of an angle α with respect to the side walls 3, 5 so as to fill each other. Connection terminals 8, 8, 8, ..., 9, which are arranged on a line and extend perpendicularly to the side walls 2, 4 are provided at the ends of the side walls 2, 4, as shown in FIG. 9 are formed.

Each of the units 1, 1 and 1 is fixed to a substrate for fixing so that the side walls 2 and 4 on both sides of the units are positioned substantially in the same straight line. In this embodiment, three are fixed to the nozzle plate 10. There is. Note that reference numerals 11 and 12 in the figure denote through holes for positioning.

On the other hand, the flexible cable 13 is composed of a flexible conductive material obtained by adhering a metal foil C (see FIG. 4) made of copper or the like to a base material B of a heat-resistant electrically insulating film such as polyimide, which constitutes a recording head. Head unit 1,
1, 1 and 1, and the end portions in the width direction have connection terminal portions 8, 8, 8 of the recording head units 1, 1, 1, 1.
.., 9, 9, 9, .. .., preferably as shown in FIG. 3B, the piezoelectric vibrators 37, 38 (Fig.
4) The connection terminal portion of the head unit 1 is cut in the end regions of the side faces 14 and 15 in the longitudinal direction by being cut into strips so as to have a large width of about ΔW so as to be bent and connected so that a certain space can be secured. 8, 8, 8, ..., 9, 9, 9,
Connection terminal portions 16 and 1 having the same arrangement pitch as ...
6, 16, ..., 17, 17, 17, ..., Side edge 1
It is formed so as to extend in the vertical direction with respect to 4 and 15.

In this embodiment, a semiconductor integrated device (not shown) that generates a drive signal based on a print signal from the outside is mounted on the flexible cable 13, and the drive signal output from the semiconductor integrated circuit is applied to the conductive patterns 18 and 1.
., 19, 19, 19, .. are supplied to the respective connection terminal portions 16, 17. In the figure, reference numeral 20 is a window for mounting the semiconductor integrated device, 21 is a conductive pattern for supplying a print signal from an external drive circuit to the semiconductor integrated device, and reference numeral 22 is a connection terminal with the external device.

FIG. 4 is a view showing one embodiment of the above-mentioned recording head in a longitudinal sectional structure of the pressure generating chamber,
Further, FIG. 5 is a diagram showing an arrangement of the pressure generating chambers 32 and 33 of the pressure generating chamber forming substrate 31, the nozzle openings 6 and 7, and the ink supply ports 46 and 47 by removing the elastic plate 34 on the upper surface which will be described later.

In FIG. 4, reference numeral 31 is a spacer, which is a substrate made of a ceramic plate such as zirconia (ZrO 2) having a thickness suitable for forming the pressure generating chambers 32 and 33 having a depth of about 150 μm. As shown in FIG. 5, the pressure generating chambers 32 and 33 are arranged such that the longitudinal axis of the pressure generating chambers 32 and 33 is inclined at an angle α with respect to the arrangement direction of the nozzle openings 6 and 7.

It should be noted that the pressure generating chambers 32 and 33 in each row are staggered so that the nozzle openings 6 and 7 in the two rows facing each other in FIG. 5 fill the gaps at an equal pitch P in the main scanning direction. Although the nozzle openings 6 and 7 are arranged, it is not necessary that the nozzle openings 6 and 7 are arranged at equal pitches in the main scanning direction, and the nozzle openings 6 and 7 may be arranged at the same position in the main scanning direction.

In the embodiment shown in FIG. 5, the distances L1 and L2 and the distances L3 and L4 are equal to the side walls 2 and 4 on both sides of the unit 1 and the two nozzle openings 6'located in diagonal areas.
7'and the nozzle openings 6 "and 7" are set to have the same distance.

Further, the position of the nozzle opening row of each unit in the sub-scanning direction is such that when the two units 1 and 1 are arranged in the vertical direction, the lowermost nozzle opening of the unit 1 located above and the lower one The distance in the sub scanning direction from the uppermost nozzle opening of the unit 1 located on the side is determined so as to be equal to the nozzle pitch of the same nozzle opening row in the unit. Regarding the position of the nozzle opening row of each unit 1 in the main scanning direction, the side wall 5 on the lower side of the unit 1 located on the upper side and the side wall 3 on the upper side of the unit 1 located on the lower side are the outer shape accuracy of the unit 1. Even if the positioning accuracy between the units is taken into consideration, the deviation amount ΔL between the nozzle opening rows is determined so that the distance ΔG that does not cause contact or interference can be obtained as the center value.
At this time, the side wall 2 has an angle β with respect to the side wall 3 and an angle γ with respect to the side wall 5.

By adopting the angle of the side walls 2 to 5 and the arrangement of the nozzle opening rows, the side walls 2 and 4 of the unit 1 are positioned on the same straight line between the two units 1 and 1. Become.

That is, the nozzle openings 6, 7 of the unit 1
Is P, the number of nozzle openings 6 and 7 is N, the first side wall 2, and the alignment lines A and A ′ of the nozzle openings 6 and 7 and the third
Let θ be an angle formed by a line B parallel to the side wall 4 of tan θ = ΔL / [(N−1) × P + P] = ΔL / (N
XP).

As a result, even if the two units 1 and 1 are arranged such that the respective side walls 2 and 4 are located on the same line, the rows of the nozzle openings 6 and 7 between the units are mutually in the main scanning direction. Although there is a gap ΔG in the sub-scanning direction and a slight gap ΔG in the sub-scanning direction, the pitch in the sub-scanning direction of the entire nozzle opening is the same even near the boundary between the two units 1 and 1 without disturbing the unit's original pitch P. Can be

Preferably, if the distance ΔL between the nozzle opening rows is set to be an integral multiple of the nozzle opening pitch in the sub-scanning direction, the dot forming position control in the main scanning direction and the clogged ink droplet ejection timing can be controlled. The control can be simplified.

Reference numeral 34 is an elastic plate, which exerts sufficient bonding force when integrally fired with the spacer 31, and
The piezoelectric vibrators 37, 38, which will be described later, are made of a material that is elastically deformed by flexural vibration, for example, a thin plate of zirconia with a thickness of about 7 μm.

Denoted at 37, 38, ... Are the above-mentioned piezoelectric vibrators, which are lower electrodes 39 formed on the surface of the elastic plate 34.
On the surface of 40, a green sheet of piezoelectric material is formed by sintering so as to face the pressure generating chambers 32 and 33.

Reference numeral 41 in the drawing denotes a lid plate integrally attached to the other surface of the spacer 31, and in this embodiment, the thickness is 100 μm.
Nozzle communication holes 42 and 43, which connect the nozzle openings 6 and 7 of the nozzle plate 10 to the pressure generating chambers 32 and 33, and reservoirs 44 and 45 described later.
And ink supply ports 46 and 47 for connecting the pressure generating chambers 32 and 33 with each other.

Reference numeral 48 is a reservoir forming plate, which is a plate material having a corrosion resistance such as a stainless steel having a thickness of 150 μm, which is suitable for forming the reservoir, and the reservoirs 44 and 45, the pressure generating chambers 32 and 33, and the nozzle openings. Nozzle communication holes 49 and 50 connecting the nozzles 6 and 7 are formed.

Of these members 31, 34, 41, 48, members 31, 34, 41 made of a ceramic material.
Is fixed integrally by firing and then fixed to a reservoir forming plate 48 made of metal or the like by a joining method suitable for joining ceramic and metal.
Is configured.

Then, upper electrodes 51 and 52 are formed on the surfaces of the piezoelectric vibrators 37 and 38 by vapor deposition or the like. At that time, the connection patterns 53 and 5 are formed in accordance with the formation of the upper electrodes 51 and 52.
4 are formed.

The connection patterns 53 and 54 are shown in FIG.
As shown in (a), the piezoelectric vibrators 3 are provided from the ends of the piezoelectric vibrators 37 and 38 to the vicinity of the side walls 2 and 4 of the unit 1.
7, 38, and the connecting terminal portion 8,
It is bent in the direction of 9 and connected to the connection terminal portions 8 and 9. Note that reference numerals 55 and 56 in the drawing denote insulating layers formed between the lower electrodes 39 and 40 and the connection patterns 53 and 54.

When fixing a plurality of recording head units 1 constructed in this way, three in this embodiment, to the nozzle plate 10, the side walls 2 and 4 on both sides of each head unit 1 are positioned on the same line. In addition, the uppermost nozzle opening facing the one head unit 1 and the lowermost nozzle opening of the other adjacent head unit 1 match the pitch P of the original nozzle openings 6 and 7 of the head unit. If the spacing ΔG is adjusted as described above, each head unit 1, 1,
1 ... Nozzle openings 6, 6, 6, ..., 7, 7, 7 ,.
Will all be on the same pitch.

Next, the flexible cable 13 has side edges 14 and 15 parallel to the side walls 2 and 4 of the recording head units 1, 1, 1 ,.
, 17, 17, 17, 17, ... are positioned so as to face the connection terminal portions 8, 8, 8 ..., 9, 9, 9 ... of each head unit 1, and the connection terminal portion 16, 17 and the connection terminal portions 8 and 9 are joined by soldering or the like so as to form a conductive relationship.

When positioning the flexible cable 13, the connection terminal portion 16 of the flexible cable 13,
, 16, 17, 17, 17, ... Are formed so as to be substantially perpendicular to the respective side edges 14, 15 of the flexible cable 13, and a plurality of head units 1, 1, 1, the side walls 2 and 4 are located on the same line, and the connection terminal portions 8, 8, 8, ..., 9, 9, 9 ,.
Are formed perpendicularly to the side walls 2 and 4, the side edges 14 and 15 of the flexible cable 13 are parallel to the side walls 2 and 4 of the head units 1, 1, 1 ,. , 16, 16, ..., 17, 17, 17, ... are aligned so as to correspond to each other, all connection terminal portions 16, 16, 16 ,.
.. are all positioned at predetermined positions.

Preferably, the connection terminal portion of the flexible cable 13 is peeled off in the lengthwise direction with a constant width to expose the copper foil forming the conductive pattern to form a tab T, and the tab T is flexible. Cable side edge 1
When bent at a right angle with a line parallel to 4 and 15 and formed into a "Z" shape, the tip side which is the connection terminal section also becomes a right angle, so the tip of each tab is connected to the connection terminal section 7 of the unit 1,
It can be molded into a shape similar to that of No. 8.

Therefore, similarly to the above, the connection terminal portion of the flexible cable 13 can be accurately aligned with the connection terminal portions 7 and 8 of the head unit 1.

In this embodiment, when the print signal and the drive voltage are supplied from the external drive circuit to the connection terminal 22, the drive signal and the drive voltage are supplied to the semiconductor integrated device (not shown) through the conductive path 21 of the flexible cable 13. Drive signals are supplied to the connection terminal portions 8 and 9 via the conductive patterns 18 and 19, and the piezoelectric vibrators 17 and 18 of the recording head units 1, 1, 1, 1 are provided via the connection patterns 55 and 56.
Is also supplied with a drive signal. As a result, the piezoelectric vibrator 3
7 and 38 are flexibly displaced to expand and contract the pressure generating chambers 32 and 33 to eject ink droplets from the nozzle openings 6 and 7.

Although a tab is formed at the end of the flexible cable and the connection is made through the tab in the above-described embodiment, only the insulating layer on the side of the flexible cable facing the recording head unit 1 is formed. Peel off the
You may make it connect from the top of a base material.

Further, in the above-mentioned embodiment, the piezoelectric vibrator is formed by adhering a ceramic green sheet, but the same effect can be obtained by applying it to a piezoelectric material formed by vapor deposition. It is clear that

Further, in the above embodiment, the semiconductor integrated circuit is provided in the flexible cable so that the drive signal is generated in the flexible cable area.
It is obvious that the same operation can be achieved even if a drive signal is generated by an external drive circuit and supplied.

[0039]

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of a recording head of the present invention with a flexible cable removed.

FIG. 2 is a diagram showing an example of a flexible cable connected to the recording head of the above.

3A and 3B are enlarged views showing a terminal portion formed near a side wall of a head unit and a connection terminal portion at a side edge of a flexible cable, respectively.

FIG. 4 is a diagram showing an example of a recording head unit constituting the ink jet recording head of the present invention with a sectional structure in the vicinity of a pressure generating chamber.

FIG. 5 is a diagram showing an arrangement of pressure generating chambers, nozzle openings, and ink supply ports, and a relationship between these and side walls.

FIG. 6 is a diagram showing an ink jet recording head using a conventional head unit.

[Explanation of symbols]

1 Recording head unit Side wall of 2, 3, 4, 5 head unit 6, 7 nozzle opening 8, 9 Recording head unit connection terminals 10 nozzle plate 13 Flexible cable 16, 17 Flexible cable connection terminals 18, 19 Conductive pattern 31 elastic plate 32, 33 Pressure generation chamber 37, 38 Piezoelectric vibrator 39, 40 lower electrode 44, 45 reservoir 46, 47 Ink supply port 51, 52 Upper electrode

Claims (8)

(57) [Claims] 1. A nozzle opening for ejecting ink droplets is arranged in a plurality of rows to form a nozzle opening row, and the nozzles are arranged so as to be inclined at a predetermined angle α with respect to the arrangement direction of the nozzle openings. A pressure generating chamber communicating with the opening; a pressure generating means for pressurizing the pressure generating chamber; and a connection terminal portion connected to the electrode of the pressure generating means by a conductive means to supply a drive signal to the pressure generating means. A rectangular recording head unit composed of first to fourth side walls, a plurality of the recording head units are arranged in the direction of the arrangement line of the nozzle openings, and the adjacent recording head units are partitioned from each other. The first and second sidewalls have an angle α with respect to the arrangement direction of the nozzle openings, and the third and fourth sidewalls intersecting the first and second sidewalls are the nozzle openings. Array The nozzle opening array line in one of the adjacent head units and the nozzle opening array line in the other of the adjacent head units have an angle θ with respect to the direction of the line so that the array pitch of the nozzle openings is the same between adjacent print head units. The ink jet recording head unit in which the nozzle opening arrangement line in the recording head unit is formed with a deviation amount in a direction perpendicular to the nozzle opening arrangement line. 2. When a plurality of nozzle openings at the lower end and the upper end of adjacent recording head units are arranged so that the pitch of the nozzle openings matches the arrangement pitch of the nozzle openings of the recording head unit, the third and fourth nozzles are arranged. 2. The angle θ is configured so that the side walls of the plate are substantially on the same line.
The ink jet recording head unit described in 1. 3. If the pitch of the nozzle openings is P, the number of nozzle openings is N, and the deviation amount is ΔL, then tan θ = ΔL / [(N−1) × P + P] = ΔL / (N
The inkjet recording head unit according to claim 1, wherein the relationship xP) is established. 4. A plurality of recording head units having a plurality of pressure generating chambers communicating with each of the plurality of nozzle openings are arranged in a direction of an arrangement line of the plurality of nozzle openings, and the plurality of recording head units are adjacent to each other. First and second partitioning
The side wall of the recording head unit is formed with an angle α with respect to the arrangement direction of the nozzle openings, and the adjacent nozzle heads are arranged such that the arrangement pitch of the nozzle openings is the same between the adjacent recording head units. The alignment line of the nozzle openings in one recording head unit of the head unit and the alignment line of the nozzle openings in the other recording head unit have a deviation amount in a direction perpendicular to the alignment line of the nozzle opening, The pitch of the openings is P, the number of nozzle openings is N, the deviation amount is ΔL, and the alignment lines of the third and fourth side walls of the recording head unit and the nozzle openings intersecting the first and second side walls. When the angle formed by and is θ, tan θ = ΔL / [(N−1) × P + P] = ΔL / (N
An ink jet recording head in which a plurality of recording head units configured so as to satisfy the following formula are arranged so that the third and fourth side walls of each unit are located on the same line. 5. The third and fourth of each head unit
A flexible cable having a side edge parallel to the side wall of the recording head unit and having a connection terminal portion connected to the connection terminal portion of the recording head unit formed near the side edge so as to extend perpendicularly to the side edge. The inkjet recording head according to claim 4. 6. The ink jet recording head according to claim 5, wherein the connection terminal portion of the flexible cable is formed as a tab. 7. The pressure generating means is composed of a piezoelectric vibrator, the tab is bent in a “Z” shape, and a constant gap is provided between the main body of the flexible cable and the piezoelectric vibrator. The inkjet recording head according to claim 6, which is secured. 8. The pressure generating means is constituted by a piezoelectric vibrator, the connection terminal portion is formed as a tab whose extension direction is substantially perpendicular to the third side wall or the fourth side wall, and the tab is “ 7. The ink jet recording head according to claim 6, which is bent into a “Z” shape so that a constant gap is secured between the main body of the flexible cable and the piezoelectric vibrator.