JPH10286949A - Ink jet head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet head which prevents a bubble from finding its way into an injection channel by promoting the separation of the bubble and also diminishing the incidence of a failure to eject an ink liquid by preventing the bubble from collecting in an introduction channel leading to an ink supply source, in a supply channel. SOLUTION: A supply channel 16 formed in a manifold 17 has a base part 49 through which an ink liquid is introduced in a direction in which the ink liquid flows away from a position 19 for the ink liquid to flow in and branched parts 50, 51 which are formed against injection channels 48 from the tip part of the base part 49 and distribute the ink liquid to each of the injection channels 48 by causing the flow of the ink liquid in a direction in which the ink liquid flows close to its inflow position 19. Even when the ink liquid flowing into the supply channel 16 contains a bubble, the bubble is separated by buoyancy during the passage of the ink liquid through the long base part 49, so that the bubble hardly enters each of the injection channels 48. Further, the bubble does not collect in the introduction channel on account of the long flow channel.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet head of an ink jet type recording apparatus for performing required recording on recording paper by ejecting ink liquid from nozzles.

[0002]

2. Description of the Related Art Conventionally, an ink jet recording apparatus has been well known as a recording apparatus having a relatively simple structure and capable of easily performing high-speed printing and high-quality printing. An ink jet head of this type of ink jet recording apparatus includes, for example, a nozzle plate in which a plurality of nozzles for ejecting ink liquid as droplets are formed, and a plurality of ejection channels formed of a piezoelectric ceramic material and communicated with each nozzle. And an manifold joined to the actuator and formed with an introduction path for introducing the ink liquid from the ink supply source, and a supply path for supplying the ink liquid introduced into the introduction path to each ejection channel. It has. Then, the volume of the ejection channel is changed by deformation of the actuator, and when the volume is reduced, the ink liquid of the ejection channel is ejected as droplets from nozzles formed in the nozzle plate. The ink liquid is supplied into the ejection channel of the actuator via the above.

FIG. 9 is a sectional view showing the inside of a supply path of a conventional manifold. In FIG. 9, a plurality of injection channels 2 are formed in an actuator 1 in two rows at a predetermined interval.
Are bifurcated from the inflow position 5 into which the ink liquid flows from the introduction path, corresponding to the row of each ejection channel 2. The ink liquid introduced from the introduction path into the supply path 4 branches into two branches and flows into each ejection channel 2 while flowing in a direction away from the inflow position 5.

[0004]

According to the experiment of the inventor, the latter method causes non-ejection of the ink liquid when a large amount of data is printed in a fixed time and when a small amount of data is printed. Hateful. This is because, in the latter case, since the flow rate of the ink liquid is low, bubbles rise upward due to buoyancy before the ink liquid reaches the ejection channel 2, adhere to the upper portion of the supply path 4 in the manifold 3, and the bubbles It is conceivable that entry into 2 will be reduced.

That is, it is difficult to control whether the flow rate of the ink liquid becomes faster or slower depending on the data amount. However, if the time during which the buoyancy acts is longer, the separation of the bubbles proceeds, and if the time is shorter, the bubbles are reduced. It becomes easy to enter the injection channel 2. Since the supply path 4 is configured as a flow path that can be immediately distributed from the introduction path to the ejection channel 2, if the ink liquid flowing into the supply path 4 contains bubbles, the bubbles are ejected. It easily enters the channel 2 and causes non-ejection of the ink liquid.

Further, if air bubbles adhering to the ejection channel 2 or the supply path 4 collect with the passage of time due to buoyancy in the introduction path leading to the ink supply source, this may cause non-ejection. An object of the present invention is to solve the above-described problems, and in the supply path, promotes separation of bubbles to suppress bubbles from entering the injection channel,
Another object of the present invention is to provide an ink jet head that suppresses bubbles from being collected in an introduction path leading to an ink supply source and reduces non-ejection of an ink liquid.

[0007]

In order to achieve the above object, according to the first aspect of the present invention, there is provided an actuator having a plurality of ejection channels for ejecting an ink liquid from nozzles, and an actuator joined to the actuator. An ink supply head for supplying an ink liquid from an ink supply source, and a manifold formed with a supply path for supplying the ink liquid introduced into the introduction path to each of the ejection channels. A base for flowing the ink liquid in a direction away from an inflow position where the ink flows into the supply path from the introduction path, and an ink formed in a direction approaching the inflow position formed from a tip end of the base in correspondence with the ejection channel. A branch for flowing a liquid and distributing the liquid to each of the injection channels.

According to this configuration, the ink liquid flowing from the introduction path into the supply path first enters the base portion, flows once in a direction away from the inflow position, then enters the branched portion, and approaches the inflow position. Since it is distributed to each injection channel while flowing in the direction, it is possible to secure a flow path corresponding to the length of the base portion after entering the supply path and before being distributed to each injection channel. Therefore, even if the ink liquid flowing into the supply path contains bubbles, when the ink liquid flows through the long base over time, the bubbles are separated by buoyancy and adhere to the flow path wall surface of the base. Therefore, bubbles are less likely to enter each injection channel. Further, bubbles adhering to the ejection channel and the supply path with the passage of time are less likely to collect in the introduction path leading to the ink supply source due to the long flow path. Therefore, non-ejection of the ink liquid caused by such bubbles can be suppressed. In addition, since the branch portion is configured to flow the ink liquid in the direction approaching the inflow position again, it is possible to secure a long flow path in the supply path without forming a long manifold, and avoid increasing the size of the manifold. it can.

According to a second aspect of the present invention, in the actuator, a plurality of rows of the plurality of injection channels are formed in the actuator, and the branching portions of the base portion correspond to the plurality of rows of the injection channels, respectively. It is characterized by being branched from the tip. Since a plurality of injection channels are formed for each row, and a branch portion is formed correspondingly, when forming the injection channels and the supply path in the actuator and the manifold, respectively,
Can be arranged efficiently.

[0010] Further, the invention described in claim 3 is based on claim 2.
In the invention described in (1), the actuator is characterized in that the plurality of injection channels are formed in two rows, and the supply path has two branch portions. When a plurality of ejection channels are formed in two rows, each ejection channel in the actuator can be arranged most effectively, and the actuator can be easily formed. In addition, the branching portion only needs to branch off from the base portion, and the manifold can be easily formed.

[0011] The invention described in claim 4 is the same as the claim 3.
In the invention described in (1), the supply path has the branch portions on both sides of the base. By disposing the branch portions on both sides of the base portion, the base portion can be disposed between each of the injection channels formed in two rows. Therefore, in the manifold, there is no waste in the arrangement in which the supply path is formed, and therefore, the ink jet head The size can be reduced.

The invention described in claim 5 is the same as the invention in claim 4.
5. The manifold according to claim 1, wherein the manifold has two partition walls for partitioning between the base and the branch portions on both sides, and a manifold between the partition walls and the injection channels formed in two rows in the actuator. The side end face is
It is characterized in that the base portion is opposed to each of the branch portions on both sides from the middle of the flow path through a gap through which a part of the ink liquid can flow. With such a configuration, the ink liquid introduced into the supply passage flows in the base toward the front end side of the base, and a part of the liquid flows out of the flow path of the base to each of the branch portions on both sides. At the time of the initial introduction of the ink liquid, since many bubbles are contained at the tip of the ink liquid to be introduced, the tip of the ink liquid is quickly released from the middle of the flow path of the base to each of the branch portions, and the bubbles are removed. Ejection can be efficiently expelled from the injection channel.

[0013] The invention described in claim 6 is the invention according to claim 5.
In the invention described in (1), the actuator includes a plate that forms an inner wall of each of the ejection channels between the ejection channels that are formed in two rows, and a manifold-side end face of the plate is formed in two rows. In addition, each of the injection channels is located on the nozzle side with respect to the edge of the outer wall on the manifold side. As described above, since the actuator is provided with the plate that forms the inner wall of each injection channel between the injection channels formed in two rows, the plate can be shifted to the nozzle side, and the partition wall and the manifold in the actuator can be provided. A gap between the side end surface can be formed, and therefore, with a simple configuration, a part of the ink liquid can flow out from the middle of the flow path of the base to each of the branch portions on both sides, so that air bubbles at the time of initial introduction can be improved. Can be kicked out.

[0014] Further, the invention according to claim 7 is based on claim 4.
In the invention described in the above, the manifold has a side wall that constitutes a flow path wall outside two branch portions, and two partition walls that partition the base portion and each of the branch portions on both sides, wherein the partition wall Is characterized in that the end face on the actuator side is located on the nozzle side with respect to the end face on the actuator side of the side wall. According to such a configuration, in joining the actuator and the manifold, the partition wall is joined to the actuator in a state where the partition wall is in close contact with the manifold-side end surface of the actuator without any gap. Therefore, no gap is formed between the partition wall and the end face on the manifold side of the actuator facing the partition wall due to a manufacturing error or the like. Therefore, during the initial introduction of the ink liquid, bubbles in the ink liquid are
In the middle of the flow path of the base, there is no residue between the partition wall and the end face on the manifold side of the actuator opposed to the partition wall, and all the ink liquid containing air bubbles flows inside the base to the tip side of the base. Flow can then flow into the branch and be expelled from each injection channel efficiently.

According to the present invention, an actuator having a plurality of ejection channels for ejecting an ink liquid from a nozzle is provided, and the ink liquid is supplied from an ink supply source and joined to the actuator. An introduction path, and a manifold in which a supply path for supplying the ink liquid introduced into the introduction path to each of the ejection channels is formed, and an inkjet head including a filter provided in the introduction path, wherein the supply path includes: A bubble reservoir is provided at a position where bubbles do not flow from the supply path to the introduction path.

[0016] Bubbles entering the supply channel and the injection channel may collect and adhere to a filter provided in the introduction channel due to buoyancy with the passage of time. For this reason, there is a problem that the filter is closed by the collected air bubbles and the ink supply source cannot supply the ink liquid to the inkjet head. In such a case,
By providing a bubble reservoir portion in the supply path, bubbles that are going to move to the filter can be trapped, so that the filter is not blocked by bubbles, and the ink liquid from the ink supply source can be satisfactorily supplied to the inkjet head. .

The invention according to claim 9 is the invention according to claim 8
In the invention described in (1), a portion corresponding to the plurality of ejection channels in the supply path of the manifold introduces the ink liquid from the introduction path from below. As described above, bubbles entering the supply path and the ejection channel try to move to the filter provided in the introduction path by buoyancy, but the ink liquid from the introduction path is removed from a portion corresponding to the ejection channel in the supply path. When the air is introduced from below, the portions of the supply path corresponding to the plurality of injection channels and the air bubbles staying in the injection channels move upward in the supply path, that is, in the direction away from the introduction path by buoyancy. Without moving to the filter side, the upper side of the portion corresponding to the plurality of injection channels in the supply path can be trapped as the bubble reservoir portion. Therefore, the filter is not blocked by such bubbles, and the ink liquid from the ink supply source can be satisfactorily supplied to the inkjet head.

[0018]

FIG. 1 is a perspective view showing one embodiment of an ink jet recording apparatus having an ink jet head according to the present invention. The color inkjet printer 21 is a printing paper 22 that uses four color inks of cyan, magenta, yellow, and black as a printing medium.
An ink-jet type ink-jet head 23 for performing printing by printing on the ink jet head;
Are provided integrally as a head unit 24,
The head unit 24 includes the inkjet head 23
Is supported by a carriage 26 so as to eject ink liquid obliquely downward onto the printing paper 22, and together with this head unit 24, an ink as an ink supply source for supplying four colors of ink liquid to the inkjet head 23. A cartridge 25 is detachably mounted on the carriage 26.

A platen roller 27 is rotatably provided opposite to the front surface of the ink jet head 23 in parallel with the reciprocating direction of the ink jet head 23. The ink jet head 23 and the platen roller 27 constitute a printing unit. . The carriage 26 has a carriage shaft 29 extending in the reciprocating movement direction of the inkjet head 23 via a carriage shaft support 28 provided below the carriage 26.
And a guide plate 54, which is capable of linearly reciprocating at the time of printing, and is connected to a belt 32 bridged between the pulleys 30 and 31, and the pulley 30 is driven to rotate by a motor (not shown). It is designed to be reciprocated linearly.

The print paper 22 is fed from a paper feed cassette (not shown) provided above the rear part of the ink jet printer 21 and is introduced between the ink jet head 23 and a platen roller 27 which is driven to rotate in the direction of arrow 33. The printed printing paper 22 is discharged in the direction of arrow 34. In FIG. 1, illustration of the paper feed mechanism for these printing papers is omitted.

A purge device 35 is provided on the side of the platen roller 27 so as to face forward of the reset state position of the ink jet head 23. The ink jet head 23 of the ink jet type solves the problem that bubbles may be accumulated at the initial introduction of the ink liquid or the like, or the ink droplets may adhere to the ejection surface, thereby causing defective ejection. There is a purge device 35 for restoring a good injection state. The purging device 35 can cover the inkjet head 23 with a cap 36 provided at a front facing position in the reset state position of the inkjet head 23. When the inkjet head 23 is covered with the cap 36,
A pump 38 driven by a cam 37 drives defective ink containing air bubbles and the like accumulated inside the inkjet head 23.
To recover the ink jet head 23. The sucked defective ink is sent to the storage unit 39.

FIG. 2 is a sectional view of a main part of the head unit 24,
FIG. 3 is a perspective view of the inkjet head 23, and FIG.
5 is a cross-sectional view taken along line AA of FIG. 3, FIG. 5 is a cross-sectional view of a main portion taken along line BB of FIG. 3, and FIG.
It is principal part sectional drawing of the -C line. These FIGS. 2, 3, 4,
The ink jet head 23 will be described with reference to FIGS.

In FIG. 2, the ink jet head 23
Is a nozzle plate 11 in which a plurality of nozzle holes (not shown) are formed, and a plurality of ejection channels 48 for communicating with the respective nozzles of the nozzle plate 11 and having a piezoelectric ceramic element, and for ejecting an ink liquid. And an introduction path 1 that is joined to the actuator 14 and that introduces the ink liquid from the ink cartridge 25.
3 and a manifold 17 having a supply path 16 for supplying the ink liquid introduced into the introduction path 13 to each ejection channel 48. An actuator-side end face of the manifold 17 in which the supply path 16 opens, 48 is joined to the end face of the actuator 14 on the manifold side where the opening 48 opens.
3 are configured.

The ink liquid from the ink cartridge 25 enters each ejection channel 48 via the introduction path 13 and the supply path 16 and changes the volume of each ejection channel 48 by deformation of the actuator 14. The ink liquid in each ejection channel 48 is ejected as a droplet from a nozzle formed in the nozzle plate 11, and when the volume is increased, the ink is supplied from the ink cartridge 25 into the ejection channel 48 of the actuator 14 via the introduction path 13 and the supply path 16. The liquid is introduced. Note that the inkjet head 23 is
May be a thermal head type using a heating element in place of the piezoelectric ceramic element, and other known types.

Then, a through hole 64 is formed in the vertical wall 63 of the head unit 24, and the introduction path 13 of the manifold 17 is formed.
The ink jet head 23 is attached to the head unit 24 by inserting the manifold 17 into the through hole 46 and bonding the manifold 17 and the vertical wall 63 of the head unit 24. As shown in FIG. 2, the ink-jet head 23 is inclined at about 45 degrees with the nozzle plate 11 down and the manifold 17 up. At this time, the supply path 16 of the manifold 17 continues downward from the introduction path 13 with the introduction path 13 at the top.

A first filter 65 in the shape of a disk is provided at the tip of the introduction path 13. When connecting the ink cartridge 25 to the seal member 66, the first filter 65 removes dust and bubbles from the ink jet head 2.
3 is prevented from entering the supply path 16.
The first filter 65 is attached to the first filter 6.
5 is welded to the end face of the introduction port 67 where the introduction path 13 is opened, and the other side of the first filter 65 is covered with a seal member 66, and the seal member 66 is connected to the manifold 17 and the through hole. 64.

The sponge-like porous material 74 is provided in the ink cartridge 25 housed in the head unit 24.
The porous body 74 is impregnated with an ink liquid. An adapter 69 for connecting to the seal member 66 is fitted into the ink supply port 68 of the ink cartridge 25, and a second filter 70 is inserted between the ink supply port 68 and the adapter 69. ing. The second filter 70 is provided in the ink cartridge 25.
When the ink is connected to the ink jet head 23, the ink liquid is prevented from spilling out from the ink supply port 68 by the surface tension of the ink liquid in the second filter 70.

The ink supply port 68 of the ink cartridge 25 and the introduction port 67 of the manifold 17 are detachably connected by fitting an adapter 69 and a seal member 66 together. And ink cartridge 2
5 is supplied from the ink supply port 68 to the adapter 69.
After passing through the first filter 65 via the seal member 66 and the first filter 65 removes dust and bubbles in the ink liquid, the ink is supplied from the introduction port 67 into the introduction path 13 of the manifold 17. Reference numeral 71 denotes a head cover that covers the inkjet head 23. Also, 61 and 62 shown in FIGS. 2, 3 and 4 are formed at both end portions of the manifold 17.
Are attached to the head unit 24 and hold the actuator 14.

Next, the ink jet head 23 will be described in detail. As shown in FIG. 5, the actuator 14 includes a pair of substrates 43 and 44 having piezoelectric ceramic elements,
A plate 45 is provided between the pair of substrates 43 and 44. The substrates 43 and 44 have a plurality of independent grooves 46 and 47, respectively. And
By joining the substrates 43 and 44 to both sides of the plate 45, the outer side walls 40 and 41 and the side
And 47, a plurality of injection channels 48 having inner walls 55 and 56 formed by plate 45. The formed plurality of injection channels 48 are arranged in two rows facing each other with the plate 45 interposed therebetween.

As shown in FIGS. 4 and 6, the supply path 16 of the manifold 17 is
A base 49 for flowing the ink liquid in a direction away from the inflow position 19 (indicated by an arrow 76) into the nozzle 6, and two rows corresponding to each of the ejection channels 48 formed in two rows from the tip of the base 49. The ink is branched and flows in a direction approaching the inflow position 19 (the direction indicated by arrows 78 and 79).
And two branch portions 50 and 51. More specifically, the introduction path 13 is formed at one end of the manifold 17, and the base 49 is formed from the inlet position 19 where the ink liquid from the introduction path 13 flows toward the other end of the manifold 17. Extends at approximately the center of its length,
At the other end, the tip of the base 49 branches into two,
The two branch portions 50 and 51 are folded back so as to sandwich them on both sides with the base 49 as a center, and extend substantially in parallel with the base 49 toward the inflow position 19. And
The base portion 49 and the branch portions 50 and 51 constitute a substantially E-shaped supply path 16. And manifold 1
7, two partition walls 52 and 53 are formed to partition the base 49 and the two branch portions 50 and 51 in order to constitute the supply path 16 having a substantially E-shape. The partition walls 52 and 53 form both inner wall surfaces of the base 49 and both inner wall surfaces of the branch portions 50 and 51, and the side wall 20 of the manifold 17 is
And 51 constitute both outer wall surfaces.

The ink liquid from the ink cartridge 25 is supplied from the introduction path 13 of the manifold 17 to the supply path 1.
The ink liquid that has flowed into the base 49 of FIG. 6 and has entered the base 49 temporarily moves away from the flow-in position 19 (direction indicated by an arrow 76), that is, the introduction path 1 in the manifold 17.
3 flows from the one end where it is formed toward the other end,
Then, at the distal end of the base 49, it enters the branched portions 50 and 51, turns back and approaches the inflow position 19 again (the direction indicated by arrows 78 and 79), that is, the direction in which the introduction path 13 is formed. It flows into each injection channel 48 while flowing.

The ink liquid thus introduced into the supply path 16 flows through the base 49 and then branches 50 and 5.
Since the air is supplied to each injection channel 48 at 1, the distance from entering the supply path 16 to being distributed to each injection channel 48 is long, and when flowing over this supply path 16 over a long period of time, bubbles are generated. Separated by buoyancy, base 4
9 is attached to the channel wall surface. Therefore, air bubbles hardly enter each injection channel 48. Further, bubbles attached to the injection channel 48 and the branch portions 50 and 51 are less likely to collect on the introduction path 13 and the first filter 65 due to buoyancy over time due to the long flow path. In particular, since the ink jet head 23 is inclined at about 45 degrees, air bubbles flow toward the upper ends of the branch portions 50 and 51 by buoyancy. Therefore, non-ejection of the ink liquid caused by such bubbles can be suppressed. Further, since the branch portions 50 and 51 are configured to flow the ink liquid in a direction approaching the inflow position 19 again, the long flow path in the supply path 16 can be secured without forming the manifold 17 to be long. The size of the manifold 17 is avoided.

In the actuator 14, a plurality of injection channels 48 are formed for each row, and branch portions 50 and 51 are formed correspondingly. Actuator 1
4 and the manifold 17 are efficiently arranged and formed. In particular, in the present embodiment, the plurality of injection channels 48 are formed in two rows, and the supply passage 16 is provided with two branch portions 50 and Since the injection channel 51 is formed, each injection channel 48 in the actuator 14 is most effectively arranged and easily formed. On the other hand, the branch portions 50 and 51 also have a simple shape that only branches from the base portion 49 into two branches. The formation of the manifold 17 is facilitated.

The supply passage 16 has the branch portions 50 and 51 arranged on both sides of the base 49, so that the base 49 is
It can be arranged between the ejection channels 48 formed in a row, and there is no waste in the arrangement in which the supply path 16 is formed in the manifold 17, so that the size of the inkjet head 23 is reduced. In addition, the flow path of the supply path 16 does not have to be formed in a substantially E-shape by the base 49 and the branch parts 50 and 51 as in the present embodiment, and for example, a plurality of branch parts may be provided. , And other shapes.

FIG. 7 is a view corresponding to FIG. 6 showing another embodiment of the present invention. In FIG. 7, the manifold-side end face 18 between the partition walls 52 and 53 and the injection channels 48 formed in two rows in the actuator 14, that is, the plate 45 of the actuator 14 is shown.
Are opposed to each other with a gap between them so that a part of the ink liquid can flow through the branch portions 50 and 51 on both sides from the middle of the flow path of the base 49.

The formation of such a gap allows the ink liquid introduced into the supply passage 16 to flow through the inside of the base 49 toward the tip of the base 49, and to flow from the middle of the flow path of the base 49 to both sides. A part of it flows out to each of the branch portions 50 and 51. At the time of the initial introduction of the ink liquid, since the tip of the ink liquid introduced by the suction operation of the pump 38 contains a lot of bubbles, the leading end of the ink liquid is transferred from the middle of the flow path of the base 49 to the branch portions 50 and 50. 51 is quickly escaped to efficiently suck and discharge air bubbles from each injection channel 48.

Further, in the present embodiment, the inner side walls 55 and 56 of each injection channel 48 are formed by the plate 45, and the plate 45 is connected to the manifold side edge 57 of the outer wall 40 and 41 of each injection channel 48.
And 58, a gap is formed between the partition walls 52 and 53 and the end face 18 on the manifold side of the actuator 14 only by being located on the nozzle side. Part of the ink liquid can flow out to the branch portions 50 and 51 on both sides from the middle, so that air bubbles at the time of initial introduction and the like can be favorably expelled.

FIG. 8 is a view corresponding to FIG. 6 showing another embodiment of the present invention, and is a view showing only the manifold 17. 8, the actuator side end faces 59 and 60 of the partition walls 52 and 53 are located on the nozzle side with respect to the actuator side end face 15 of the side wall 20. When the manifold 17 is configured in this manner, in joining the manifold 17 and the actuator 14, the partition walls 52 and 53 are joined to the manifold-side end face 18 of the actuator 14 without any gap. For this reason, the partition walls 52 and 5
A gap due to a manufacturing error or the like is not formed between the actuator 3 and the manifold-side end face 18 of the actuator 14 facing the partition walls 52 and 53. Therefore, during the initial introduction of the ink liquid and the like, bubbles in the ink liquid are generated in the middle of the flow path of the base 49 by the partition wall 5.
2 and 53 and the manifold-side end face 18 of the actuator 14 facing the partition walls 52 and 53, and all the ink liquid containing air bubbles passes through the inside of the base 49 in the front side of the base 49. , And thereafter flow into the branches 50 and 51 and can be efficiently expelled from each injection channel 48.

Further, in the present embodiment, the ink cartridge 25 in which the porous body 74 is impregnated with the ink liquid is used as the ink supply source. Is acted upon by the back pressure from the ink cartridge 25 side. Therefore, as shown by the phantom line in FIG. 2, after performing the purging operation by covering the nozzle plate 11 with the cap 36 of the purge device 35, the air changes from the nozzle due to the pressure change when the cap 36 is separated from the nozzle plate 11. Each injection channel 48 may enter. Alternatively, when air bubbles enter the ejection channel 48 or the supply path 16 at the time of the initial introduction of the ink liquid, for example, the retained air bubbles may be removed from the first filter 65 provided in the introduction path 13 by buoyancy over time. To the first filter 65
May be closed, and the supply of the ink liquid from the ink cartridge 25 to the inkjet head 23 may not be possible.

However, the branches 50 and 51 of the supply path 16 to which each injection channel 48 communicates are connected directly to the introduction path 13.
And is in communication with the introduction path 13 via the base 49. In addition, the direction in which the ink liquid flows is opposite between the base 49 and the branches 50 and 51. Therefore, the branch portions 50 and 51
The arrangement is such that air bubbles do not flow from the supply path 16 to the introduction path 13, and can be a bubble storage portion in the supply path. Therefore, the air bubbles that have entered the respective injection channels 48 adhere to and stay on the ceiling surfaces 72 and 73, as shown in FIG. 6, especially at the branch portions 50 and 51, and move toward the introduction path 13 by buoyancy. I will not do it. On the other hand, air bubbles adhering to the ceiling surfaces 72 and 73 and the like can be easily removed by a purge operation.
Therefore, the air bubbles that are going to move to the first filter 65 can be trapped by using the branch portions 50 and 51 as air bubble storage portions, so that the first filter 65 is not blocked by the air bubbles, and Ink can be supplied satisfactorily.

As shown in FIG. 2, since the ink jet head 23 is supported by the carriage 26 so as to eject the ink liquid obliquely downward onto the printing paper 22, a plurality of ink jet heads 23 are provided in the supply path 16 of the manifold 17. Corresponding to the injection channel 48 of the
And 51, the ink liquid from the introduction path 13
It is configured to be introduced from below through the. That is, the ink liquid that has flowed into the supply path 16 from the introduction path 13 flows downward in the base 49, and is then introduced into the branches 50 and 51 from below. While flowing toward (arrow 75
Are distributed to each injection channel 48.

In this configuration, branch portions 50 and 5
1 and the air bubbles staying in each of the injection channels 48, in the branches 50 and 51, due to buoyancy,
In other words, it moves in a direction away from the introduction path 13 and accumulates at the distal ends of the branch portions 50 and 51, so that the distal end serves as a bubble reservoir portion, so that bubbles can be trapped well.
Therefore, the air bubbles do not move to the first filter 65 side, and the air bubbles do not block the first filter 65. Therefore, the ink liquid can be satisfactorily supplied from the ink cartridge 25 to the inkjet head 23.

In the ink jet head 23, the nozzles may be arranged horizontally or horizontally or vertically downward.
In the case of horizontal horizontal orientation, the supply path 16
Is desirably arranged thereunder. In either case,
Almost the same operation and effect can be achieved.

[0044]

As described above, according to the first aspect of the present invention, the supply path is formed from the base for flowing the ink liquid in a direction away from the inflow position where the ink flows from the introduction path to the supply path, and from the tip of the base. And a plurality of branches that are branched into rows corresponding to the ejection channels and have a plurality of branches that allow the ink liquid to flow in a direction approaching the inflow position, so that the ink liquid that flows into the supply path from the introduction path is First, it flows into the base part, flows in a direction away from the inflow position, then flows into the branching portion, flows again in the direction approaching the inflow position, and flows into each injection channel. Even if the distance until the ink is distributed to the channel is long and the ink liquid flowing into the supply path contains bubbles, the bubbles are separated by buoyancy when the ink liquid flows over the long base over time. Channel wall It is deposited. Therefore, bubbles are less likely to enter each injection channel. Further, bubbles adhering to the ejection channel and the supply path with the passage of time are less likely to collect in the introduction path leading to the ink supply source due to the long flow path. Therefore, non-ejection of the ink liquid caused by such bubbles can be suppressed. In addition, since the branch portion is configured to flow the ink liquid in the direction approaching the inflow position again, it is possible to secure a long flow path in the supply path without forming a long manifold, and avoid increasing the size of the manifold. it can.

According to the second aspect of the present invention, a plurality of injection channels are formed for each row, and a branch portion is formed corresponding to the plurality of injection channels. When they are formed on the actuator and the manifold, respectively, they can be arranged efficiently. According to the third aspect of the present invention, a plurality of injection channels are formed in two rows in the actuator, and the supply path is formed in two rows.
Since there are two branches, each injection channel in the actuator can be arranged most effectively, and the actuator can be easily formed. In addition, the branching portion only needs to branch off from the base portion, and the manifold can be easily formed.

According to the fourth aspect of the present invention, by disposing the branch portions on both sides of the base portion, the base portion can be disposed between the injection channels formed in two rows, and the supply passage in the manifold is formed. There is no waste in the formed arrangement, and thus the size of the inkjet head can be reduced. According to the fifth aspect of the present invention, since there is a gap formed on the manifold side end face between the partition wall and the two ejection channels formed in the actuator, the ink liquid introduced into the supply path is provided. Flows through the base toward the tip end of the base, and part of the base flows out of the flow path of the base to each of the branch portions on both sides. Quickly escape the tip of the ink liquid from the middle of the base flow path to each branch,
Bubbles can be efficiently expelled from each injection channel.

According to the invention described in claim 6, the actuator is provided with a plate that forms the inner wall of each injection channel between the two rows of injection channels. Just slide it to the side,
A gap can be formed between the partition wall and the end face on the manifold side of the actuator, and with a simple configuration, a part of the ink liquid can flow out of the flow path of the base to each of the bifurcations on both sides. Bubbles can be satisfactorily expelled at times.

According to the seventh aspect of the present invention, the end face of the partition wall on the actuator side is located on the nozzle side with respect to the end face of the side wall on the actuator side. The partition wall is joined to the end face of the actuator on the manifold side without any gap. Therefore, no gap is formed between the partition wall and the end face on the manifold side of the actuator facing the partition wall due to a manufacturing error or the like. Therefore, during the initial introduction of the ink liquid or the like, bubbles in the ink liquid do not remain between the partition wall and the end face of the actuator facing the partition wall in the middle of the flow path of the base. Can flow all the way through the base toward the distal end of the base, and then flow into the branch to be expelled from each ejection channel efficiently.

According to the eighth aspect of the present invention, since the supply path has the bubble reservoir at a position where bubbles do not flow from the supply path to the introduction path, the bubbles are buoyant in the supply path. Therefore, even if the filter is moved to the filter side, such bubbles can be trapped by the bubble reservoir, so that the filter is not blocked by the bubbles, and the ink liquid from the ink supply source can be satisfactorily supplied to the ink jet head.

According to the ninth aspect of the present invention, since the ink liquid from the introduction path is introduced from below into the portion corresponding to the plurality of ejection channels in the supply path of the manifold, Bubbles that have entered the injection channel move upward in the supply path due to buoyancy, that is, move in a direction away from the introduction path, so they do not move to the filter side, and a portion corresponding to a plurality of injection channels in the supply path. Can be trapped by using the upper side of the as a bubble reservoir portion. Therefore, the filter is not blocked by such bubbles, and the ink liquid from the ink supply source can be satisfactorily supplied to the inkjet head.

[Brief description of the drawings]

FIG. 1 is a perspective view showing one embodiment of an ink jet recording apparatus of the present invention.

FIG. 2 is a sectional view of a main part of a head unit of the ink jet recording apparatus of FIG.

FIG. 3 is a perspective view of the inkjet head of FIG. 2;

FIG. 4 is a sectional view taken along line AA in FIG.

FIG. 5 is a sectional view of a principal part taken along line BB in FIG. 3;

FIG. 6 is a sectional view of a principal part taken along line CC in FIG. 3;

FIG. 7 is a diagram showing another embodiment corresponding to FIG. 6;

FIG. 8 is a diagram showing a manifold according to another embodiment corresponding to FIG. 6;

FIG. 9 is a diagram showing a conventional example corresponding to FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 13 Introduction path 14 Actuator 15 Actuator side end face of side wall 16 Supply path 17 Manifold 18 Manifold side end face 19 Inflow position 20 Side wall 23 Inkjet head 25 Ink cartridge 45 Plate 48 Injection channel 49 Base 50,51 Branch 52,53 Partition wall 57, 58 Manifold-side edge 59,60 Actuator-side end surface of partition wall 65 First filter

Claims (9)

[Claims] An actuator having a plurality of ejection channels for ejecting an ink liquid from a nozzle,
An inkjet head which is joined to the actuator and has an introduction path for introducing an ink liquid from an ink supply source, and a manifold formed with a supply path for supplying the ink liquid introduced to the introduction path to each of the ejection channels. The supply path is formed corresponding to the ejection channel from a leading end of the base and a base for flowing the ink liquid in a direction away from an inflow position flowing from the introduction path into the supply path, and is formed at the inflow position. A branch portion for flowing the ink liquid in the approaching direction and distributing the ink liquid to each of the ejection channels. 2. The actuator, wherein a plurality of rows of the injection channels are formed in a plurality of rows, and the branch portion is branched from a distal end of the base section so as to respectively correspond to the plurality of rows of the injection channels. Item 2. The inkjet head according to Item 1. 3. The ink jet head according to claim 2, wherein a plurality of the ejection channels are formed in two rows in the actuator, and the supply path has two branch portions. 4. The ink jet head according to claim 3, wherein the supply path has the branch portions on both sides of the base. 5. The manifold has two partition walls that partition between the base portion and the branch portions on both sides, and the manifold side between the partition walls and each of two rows of injection channels in the actuator. 5. The end face is opposed to a middle part of the flow path of the base part with a gap through which a part of the ink liquid can flow to each of the branch parts on both sides.
2. The inkjet head according to item 1. 6. The actuator includes a plate that forms an inner wall of each of the injection channels between the injection channels formed in two rows, and a manifold-side end surface of the plate is formed in two rows. The inkjet head according to claim 5, wherein each of the ejection channels is positioned on the nozzle side with respect to a manifold-side edge of an outer wall. 7. The manifold has a side wall that constitutes a flow path wall outside two branch portions, and two partition walls that partition the base portion and each of the branch portions on both sides. The actuator-side end surface is located on the nozzle side with respect to the actuator-side end surface of the side wall.
2. The inkjet head according to item 1. 8. An actuator having a plurality of ejection channels for ejecting an ink liquid from nozzles,
A manifold that is joined to the actuator and that has an introduction path for introducing the ink liquid from an ink supply source, and a supply path for supplying the ink liquid introduced to the introduction path to each of the ejection channels; and An ink jet head comprising: a filter provided in the ink jet head, wherein the supply path has a bubble reservoir at a position where bubbles do not flow from the supply path to the introduction path. 9. The ink jet head according to claim 8, wherein a portion corresponding to the plurality of ejection channels in the supply path of the manifold introduces the ink liquid from the introduction path from below.