JPH10272776A - Ink jet recording head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To decrease occupation width in the main scanning direction by inclining the arranging direction of nozzle against the arranging direction of ink channel thereby reducing the driving power of a driver and increasing the density in the subscanning direction. SOLUTION: An ink jet recording head 20 comprises a large diameter ink droplet jetting head part 21, and a small diameter ink droplet jetting head part 22. The arranging direction D1 of large diameter nozzle 31 at the large diameter head part 21 is inclined by an angle θ1 against the main scanning direction X and the subscanning direction Y and the angle θ1 is set at 30 deg.. Similarly, the arranging direction D2 of small diameter nozzle 32 at the small diameter head part 22 is inclined by an angle θ1=30 deg.. Since the pitch p1 of the large and small diameter nozzles 31, 32 in the subscanning direction is 1/2 of the pitch p2 of the large and small diameter nozzles 31, 32 in the arranging direction D1, D2, nozzle density is increased in the subscanning direction Y. Consequently, burden on a driver 45 is lessened and a small capacity driver can be employed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording head which is detachably mounted on a carriage of an ink jet recording apparatus and which prints an image by discharging ink.

[0002]

2. Description of the Related Art FIG. 9 shows an example of an ink jet recording apparatus, in which an ink jet recording head 1 is mounted on a carriage 2. The carriage 2 is engaged with the guide rail 3 and the ball screw 4, and reciprocates in the main scanning direction X according to the rotation of the ball screw 4. Also,
The paper P, which is the transfer material, is transported by the backup roll 5 in a direction orthogonal to the main scanning direction X (sub scanning direction Y).

As shown in FIG. 10, the ink jet recording head 1 has a large-diameter head portion provided with a plurality of large-diameter nozzles 6 for discharging large-diameter ink droplets in order to expand the range of ink droplet diameter adjustment. 7 and a small-diameter head 9 provided with a plurality of small-diameter nozzles 8 for discharging small-diameter ink droplets.

[0004] Both the large diameter head section 7 and the small diameter head section 9
One ink storage chamber 1 having an ink supply inlet 11a
It has one and a plurality of ink cavities 12, which are connected via an inklet 13. At the tip of each ink cavity 12, large or small diameter nozzles 6, 8 are formed. In addition, a piezoelectric member 16 as an ink pressurizing source is arranged corresponding to each ink cavity 12. When a voltage is applied from the driver 17, the piezoelectric member 16 is deformed in the thickness direction. As a result, the ink in the ink cavity 12 is pressurized and ejected from the nozzles 6 and 8 as ink droplets.

[0005]

In the ink jet recording head 1 shown in FIG. 10, the ink cavities 12 extend in the main scanning direction X, and the ink cavities 12 are provided for each of the large diameter head 7 or the small diameter head 9. Are arranged in the sub-scanning direction Y. The large-diameter nozzles 6 and the small-diameter nozzles 8 are also arranged in a straight line in the sub-scanning direction Y, respectively. Therefore, when printing one straight line 10 extending in the sub-scanning direction Y with the ink jet recording apparatus including the ink jet recording head 1, when the head 1 comes to a predetermined position in the main scanning direction X, the large-diameter head unit It is necessary to simultaneously drive all the piezoelectric members 16 of the small-diameter head section 7 or 7 and eject ink droplets from all the large-diameter nozzles 6 or the small-diameter nozzles 8. Therefore, in the head 1, it is necessary to use a large-capacity driver 7 as the driver 7. For example,
When the piezoelectric member 16 is of a laminated type, the current value required to drive one piezoelectric member 16 varies depending on the number of laminated layers and the area, but is about several mA to 100 mA in FIG. Therefore, in order to simultaneously drive all the piezoelectric members 16 of the large diameter head section 7 or the small diameter head section 9, a current value of about 1 / 10A to several tens A is required.

In general, in an ink jet recording head, it is required to increase the density of the nozzles in order to increase the printing speed. In the structure shown in FIG. 10, the large-diameter nozzle 6 and the small-diameter nozzle 8 are used. Pitch p1 in the sub-scanning direction Y
Needs to be set to be at least larger than the width of each ink cavity 16, and it is not possible to increase the density in the sub-scanning direction Y.

Further, the large diameter head 7 and the small diameter head 9
When the length L1 in the extending direction of the ink cavities 12 is longer than the length L2 in the direction in which the ink cavities 12 are arranged, the ink of the large diameter head 7 and the small diameter head 9 as shown in FIG. When the cavities 12 are arranged so as to face each other in the main scanning direction, the occupied width L3 of the carriage 2 as a whole in the main scanning direction X increases.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems in the conventional ink jet recording head, and has been made to reduce the driving force of the driver, increase the density in the sub-scanning direction, and reduce the occupied width in the main scanning direction. The task is to plan.

[0009]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention is directed to a plurality of ink jet recording apparatuses having a carriage detachably mounted, one end communicating with an ink storage chamber, and the other end provided with a nozzle. An ink jet recording head comprising a plurality of ink channels, which drives ink pressurizing means corresponding to each ink channel to pressurize ink and discharge the ink from nozzles, wherein the arrangement direction of the nozzles corresponds to the arrangement direction of the ink channels. It is characterized by having an inclination. The ink pressurizing means may be a so-called bubble jet type, in addition to the piezoelectric member made of PZT.

Preferably, the arrangement direction of the ink channels coincides with the main scanning direction, and the arrangement direction of the nozzles is inclined with respect to the main scanning direction and the sub-scanning direction.
The angle of the nozzle arrangement direction with respect to the main scanning direction is 0.
It is preferably larger than 45 ° and equal to or smaller than 45 °.

More specifically, the base ends of the ink channels are arranged in the main scanning direction, each ink channel extends in the sub-scanning direction, and the length of each ink channel is the same. It is preferred that the nozzle arrangement direction is changed so that the nozzle arrangement direction is inclined with respect to the main scanning direction and the sub-scanning direction.

Alternatively, the base ends of the ink channels are arranged in the main scanning direction, the ink channels extend in the sub-scanning direction, and the lengths of the ink channels are different, so that the ink channels are fixed from the front end of each ink channel. A nozzle may be provided at a distance and the nozzle arrangement direction may be inclined with respect to the main scanning direction and the sub-scanning direction.

Further, the base ends of the ink channels are arranged inclined with respect to the main scanning direction and the sub-scanning direction.
Each ink channel extends in the sub-scanning direction, and the length of the ink channel is the same. A nozzle is provided at a fixed distance from the tip of each ink channel, and the arrangement direction of the nozzles with respect to the main scanning direction and the sub-scanning direction. May be tilted.

It is preferable that a large diameter ink droplet discharging head and a small diameter ink droplet discharging head are provided. In this case, it is preferable that the size of the large-diameter ink droplet ejection head unit and the small-diameter ink droplet ejection head unit in the extending direction of the ink channel is larger than the dimension in the ink channel arrangement direction.

[0015]

The ink jet recording head according to the present invention has various features because the nozzle arrangement direction is inclined with respect to the ink channel arrangement direction. That is, when the arrangement direction of the ink channels coincides with the main scanning direction and the arrangement direction of the nozzles is inclined with respect to the main scanning direction and the sub-scanning direction, when printing a straight line extending in the sub-scanning direction, It is sufficient to drive the ink pressurizing means corresponding to the nozzles provided in the plurality of ink channels one by one, and a low-capacity driver can be used.

Further, since the arrangement direction of the nozzles is inclined with respect to the main scanning direction and the sub-scanning direction, the pitch of the nozzles in the sub-scanning direction becomes smaller than the pitch in the arrangement direction of the nozzles. The density can be increased.

Further, when the size of the large-diameter ink droplet ejection head portion and the small-diameter ink droplet ejection head portion in the extending direction of the ink channel is larger than the dimension in the ink channel arranging direction, the ink channel arranging direction is Is made to coincide with the main scanning direction, so that the occupied width in the main scanning direction can be reduced.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention shown in the drawings will be described in detail. The ink jet recording head 20 according to the first embodiment shown in FIGS. 1 to 3 is mounted on the carriage 2 of the ink jet recording apparatus as shown in FIG. 10 and reciprocates in the main scanning direction X.
The inkjet recording head 20 includes a large-diameter ink droplet discharge head unit 21 (hereinafter, referred to as a “large-diameter head unit 21”) and a small-diameter ink droplet discharge head unit 22 (hereinafter, referred to as a “small-diameter head unit 22”). The large-diameter head portion 21 and the small-diameter head portion 22 are
4, the partition 25, the vibration plate 26, and the substrate 27 are stacked and integrally formed.

The channel plate 24 is made of a non-conductive material such as synthetic resin, glass, ceramics, or a metal, or the like, and is formed by etching a portion (facing surface) facing the partition 25 by a processing method such as etching. A plurality of ink cavities 30 for accommodating ink 28, nozzles 31 and 32 for ejecting ink 28 of each ink cavity 30, an ink supply chamber 33 for accommodating ink 28, and each ink cavity in diameter head 21 and small diameter head 22. 30 and ink supply chamber 3
3 is formed.
Reference numeral 33a denotes an ink supply inlet provided in the ink supply chamber 33.

The partition 25 is made of a thin film made of a conductive material.
6 is fixed.

The diaphragm 26 is made of a well-known piezoelectric material, and the upper and lower surfaces thereof are provided with a conductive metal layer used as a common electrode and an individual electrode, respectively.
7 is fixed. Further, the diaphragm 26 is fixed to the substrate 27 with a conductive adhesive 36 (see an enlarged cross-sectional view (a) in FIG. 2), and then a groove 37 is formed by dicing (not shown) to be divided. The piezoelectric member 38 corresponding to the ink cavity 30 and the adjacent piezoelectric member 3
8 and a wall 40 surrounding them. Note that the piezoelectric member 38 constitutes the ink pressurizing means of the present invention. In addition, the conductive metal layers provided above and below the piezoelectric member 38 by the dicing process are also separated by the grooves 37, respectively.
As shown in (b), the metal layer facing the partition 25 is the common electrode 41, and the metal layer facing the substrate 27 is the individual electrode 42.

The substrate 27 is made of a non-conductive material such as a synthetic resin, and has a conductive lead portion 43 (see a detailed sectional view in FIG. 2) corresponding to the piezoelectric member 38 of each of the head portions 21 and 22 on the surface facing the diaphragm 26. (See (a)) is formed by a known method such as sputtering or vapor deposition, and the individual electrodes 42 formed as described above correspond to the corresponding conductive lead portions 43.
Are electrically connected to each other via a conductive adhesive 36. Then, in a region where the common electrode 41 and the individual electrode 42 face each other, a polarization process is performed by applying a high voltage while preheating the piezoelectric members 38 in advance, and the piezoelectric members 38 corresponding to the ink cavities 30 are activated. Area 4
There are four. The individual electrode 42 is connected to the driver 45 via the conductive lead 43, and the common electrode 41 is connected to the ground.

The ink supply chamber 33 of the large diameter head 21 is
The ink supply chamber 33 has a plurality of (e.g., eight in the present embodiment) elongated ink cavities 30 extending in the sub-scanning direction Y via the inklets 34. Have been. The lengths A1 of the eight ink cavities 30 are the same. The eight ink cavities 30 are arranged in the main scanning direction X and are equidistant and parallel to each other.

The large-diameter nozzles 31 provided in each of the ink cavities 30 of the large-diameter head portion 21
The distance A2 from the leading end 30a of the zero is gradually increased from the upstream side (left side in FIG. 1) in the main scanning direction X toward the downstream side (right side in FIG. 1). Thus, the arrangement direction D1 of the large-diameter nozzles 31 is inclined with respect to the main scanning direction X and the sub-scanning direction Y, and the angle θ1 formed by the arrangement direction D1 with the main scanning direction X, which is the arrangement direction of the ink cavities 30, is 30 °. Therefore, as shown in an enlarged manner in FIG. 4, the pitch p1 in the sub-scanning direction Y is １ ／ of the pitch p2 of the large-diameter nozzles 31 in the arrangement direction D1, and the nozzle density in the sub-scanning direction Y Is high.

In the small-diameter head section 32, like the large-diameter head section 31, eight ink cavities 30 of the same length A1 are arranged at equal intervals and parallel to each other in the main scanning direction X. The distance A2 from the tip 30a of the ink cavity 30 to the small-diameter nozzle 32 is gradually increased from the upstream side (left side in FIG. 1) in the main scanning direction X to the downstream side (right side in FIG. 1). The arrangement direction D2 is inclined with respect to the main scanning direction X and the sub-scanning direction Y, and the angle θ1 between the arrangement direction D2 and the main scanning direction X is 30.
°. Therefore, the pitch p1 of the small-diameter nozzles 32 in the sub-scanning direction is 1/2 of the pitch p2 of the small-diameter nozzles 32 in the arrangement direction D2, and the nozzle density in the sub-scanning direction Y is high.

The ink jet recording head 20
If so, the load on the driver 45 is reduced, and a relatively small-capacity driver can be used. That is,
As shown in FIG. 10, a straight line 1 in the sub-scanning direction Y
When printing 0, the arrangement directions D1 and D2 of the nozzles 31 and 32 are inclined with respect to the main scanning direction X and the sub-scanning direction Y as described above. The nozzles 31 and 32 sequentially pass through the position in the main scanning direction X corresponding to the straight line 10 from the downstream side (the right side in FIG. 1) in the main scanning direction X. Therefore, each nozzle 3
When the nozzles 1 and 32 reach the position corresponding to the straight line 10, the driver 45 only needs to apply a voltage to the piezoelectric members 38 corresponding to the nozzles 31 and 32 to drive the nozzles.
All nozzles 3 of large diameter or small diameter head portions 21 and 22
It is not necessary to simultaneously drive the piezoelectric members 38 corresponding to 1 and 32. Therefore, the driver 45 may have a relatively small capacity.

The large diameter head 21 and the small diameter head 2
In both cases, the length L1 in the extending direction of the ink cavity 30 is:
The large-diameter head portion 21 and the small-diameter head are longer than the length L2 of the ink cavities 12 in the arrangement direction, but are arranged so that the ink cavities 30 of the large-diameter and head portions 21 and 22 are aligned in the main scanning direction X as shown in FIG. Since the unit 22 is disposed, the main scanning of the carriage 2 as a whole as compared with the case where the large-diameter head unit 7 and the small-diameter head unit 9 are disposed so as to face in the main scanning direction X as shown in FIG. The occupied width L3 in the direction X is reduced.

In the ink jet recording head 20 according to the second embodiment shown in FIG. 5, similarly to the first embodiment, each of the head portions 21 and 22 has an arrangement direction D1 of the nozzles 31 and 32.
The angle θ of D2 with respect to the main scanning direction X, which is the arrangement direction of the ink cavities 30, is set to 30 °. However,
In the second embodiment, the length A1 of the ink cavity 30 is gradually increased from the downstream side (right side in the drawing) in the main scanning direction, and a distance A2 from the nozzles 31 and 32 to the tip 30a of the ink cavity 30 is required. It is set to be the minimum constant distance. With this configuration, it is possible to prevent bubbles from remaining between the nozzles 31 and 32 and the tip 30a of the ink cavity 30, and to prevent a decrease in the control accuracy of the ink ejection amount due to the remaining bubbles. it can. Other configurations and operations of the second embodiment are the same as those of the first embodiment. Therefore, in FIG. 5, the same elements as those of the first embodiment are denoted by the same reference numerals and description thereof is omitted.

In the ink-jet recording head 20 of the third embodiment shown in FIG. Angle θ2.
Also, the ink cavities 30 are provided for each of the head portions 21 and 22.
And the length A3 of the inklet 34 are set to be the same. Further, the distance A2 from the nozzles 31 and 32 to the tip 30a of the ink cavity 30 is also set to a necessary minimum constant distance. Nozzle 3 of each head part 21, 22
The angle θ1 of the arrangement directions D1 and D2 of the arrays 1 and 32 with respect to the main scanning direction X is 30 °, and the advantage that the driver 45 having a relatively low capacity can be used as in the first embodiment is obtained.

Further, the nozzle 3 is connected to the connecting portion between the ink storage chamber 33 and the inklet 34 for each of the heads 21 and 22.
Since the distances to the ink cavities 33 are constant, the length of the active region 44 of the piezoelectric member 38 corresponding to each ink cavity 33 (see FIG. 2) is the same for each of the heads 21 and 22. Therefore, in order to discharge the same amount of ink droplets to each of the nozzles 31 and 32 of one of the head portions 21 and 22, the same voltage may be applied to the piezoelectric member 38 corresponding to each of the nozzles 31 and 32. Control of the droplet discharge amount is further facilitated. Further, since the distance A2 from the nozzles 21 and 22 to the tip 30a of the ink cavity 30 is set to a necessary minimum constant distance as described above, it is possible to prevent bubbles from remaining in the ink cavity 30 as in the second embodiment. Can be.

In the ink jet recording head 20 of the fourth embodiment shown in FIG. 7, two large-diameter heads 21 and 22 and two small-diameter heads 22 and 22 similar to the first embodiment are used.
Are arranged diagonally. That is, the ink supply chamber 33 on the upstream side in the main scanning direction X (left side in the figure)
Eight ink cavities 30 each provided with a large-diameter nozzle 31 on the downstream side (upper side in the figure) in the sub-scanning direction Y
Are connected and the upstream side in the sub-scanning direction Y (the lower side in the figure)
Are connected to eight ink cavities 30 each having a small-diameter nozzle 32. On the other hand, a small-diameter nozzle 32 is provided downstream of the sub-scanning direction Y (upper side in the figure) in the ink supply chamber 33 downstream in the main scanning direction X (right side in the figure).
Are connected to the eight ink cavities 30 provided with
Eight ink cavities 30 provided with large-diameter nozzles 31 are connected on the upstream side (the lower side in the figure) in the sub-scanning direction Y. The ink cavities 30 of the heads 21 and 22 are arranged in the main scanning direction X, and the nozzles 31 and 32
Are inclined with respect to the main scanning direction X and the sub-scanning direction Y. If two heads 21 and 22 are provided in the sub-scanning direction Y from one ink cavity 30 in this manner,
The nozzle density in the sub-scanning direction X can be further increased.

In the fourth embodiment, as in the second embodiment, the length of the ink cavities 30 is made different from the nozzles 31 and 32 so that the leading ends 3 of the ink cavities 30 are formed.
0a may be the minimum constant distance, and as in the third embodiment, the distance from the connection between the ink supply chamber 33 and the inklet 34 to the nozzles 31 and 32 may be different for each of the heads 21 and 22. May be fixed.

The ink cavity recording head 20 of the fifth embodiment shown in FIG. 8 has a structure in which the small-diameter head section 22 is eliminated and only the large-diameter head section 21 is provided in the first embodiment. Note that, in this case as well, as in the second embodiment, the nozzle 21 is moved from the tip
It is needless to say that the distance from the connection between the ink supply chamber 33 and the inklet 34 to the nozzle 21 may be constant as in the third embodiment.

The present invention is not limited to the above embodiment, and various modifications are possible. For example, in the above embodiment, the angle θ1 of the arrangement directions D1 and D2 of the nozzles 21 and 22 with respect to the main scanning direction X is set to 30 °, but the ink cavities 30 are arranged in the main scanning direction X. If the angle θ1 is set in the range of 0 <θ ≦ 45 °, the pitch p1 in the sub-scanning direction Y is smaller than the pitch p2 in the arrangement directions D1 and D2 of the nozzles 21 and 22,
It is possible to increase the density in the sub-scanning direction Y. Further, if the common electrode 41 and the individual electrode 42 for applying a voltage to the piezoelectric member 38 are formed on a surface that does not use the partition 25, a non-conductive conductive plate 26 made of resin, ceramics, glass, or the like may be used. Can be. Furthermore, the ink pressurizing means is not limited to a piezoelectric member, and may be, for example, a so-called bubble jet type.

[Brief description of the drawings]

FIG. 1 is a front view showing an inkjet recording head according to a first embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a sectional view taken along line III-III of FIG.

FIG. 4 is a partially enlarged view of a portion IV in FIG. 1;

FIG. 5 is a front view showing an ink jet recording head according to a second embodiment of the present invention.

FIG. 6 is a front view showing an ink jet recording head according to a third embodiment of the present invention.

FIG. 7 is a front view showing an ink jet recording head according to a fourth embodiment of the present invention.

FIG. 8 is a front view illustrating an inkjet recording head according to a fifth embodiment of the present invention.

FIG. 9 is a schematic perspective view showing an ink jet recording apparatus.

FIG. 10 is a front view showing an example of a conventional ink jet recording head.

[Explanation of symbols]

21 large-diameter nozzle section 22 small-diameter nozzle section 30 ink cavity 31 large-diameter nozzle 32 small-diameter nozzle 33 ink storage chamber 34 inklet X main scanning direction Y sub-scanning direction

Claims (7)

[Claims] 1. An ink jet recording apparatus, which is detachably attached to a carriage of an ink jet recording apparatus, and has one end communicating with an ink storage chamber,
An ink jet recording head comprising a plurality of ink channels provided with nozzles at the other end, and driving ink pressurizing means corresponding to each ink channel to pressurize ink and discharge the ink from the nozzles. An ink jet recording head having an inclination with respect to an arrangement direction of ink channels. 2. The method according to claim 1, wherein the arrangement direction of the ink channels coincides with the main scanning direction, and the arrangement direction of the nozzles is inclined with respect to the main scanning direction and the sub-scanning direction. Inkjet recording head. 3. The position of a nozzle in each ink channel, wherein the base ends of the ink channels are arranged in the main scanning direction, each ink channel extends in the sub-scanning direction, and the length of the ink channel is the same. 3. The ink jet recording head according to claim 2, wherein the nozzle arrangement direction is inclined with respect to the main scanning direction and the sub-scanning direction by making the nozzles different from each other. 4. A base end of an ink channel is arranged in a main scanning direction, each ink channel extends in a sub-scanning direction, and a length of the ink channel is changed. 3. The ink jet recording head according to claim 2, wherein nozzles are provided at a distance, and the arrangement direction of the nozzles is inclined with respect to the main scanning direction and the sub scanning direction. 5. The ink channel according to claim 1, wherein a base end of the ink channel is arranged obliquely with respect to the main scanning direction and the sub-scanning direction, and each ink channel extends in the sub-scanning direction and has the same length. 3. The ink jet recording head according to claim 2, wherein nozzles are provided at a certain distance from the tip of each ink channel, and the nozzle arrangement direction is inclined with respect to the main scanning direction and the sub-scanning direction. 6. The ink jet recording head according to claim 2, further comprising a large diameter ink droplet discharging head and a small diameter ink droplet discharging head. 7. A method according to claim 6, wherein the dimension of the large-diameter ink droplet ejection head and the small-diameter ink droplet ejection head in the extending direction of the ink channel is larger than the dimension of the ink channel in the arrangement direction. 3. The ink jet recording head according to item 1.