JP2003011358A - Ink jet head and ink jet recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet head having a nozzle plate which is not stripped easily even if the surface is wiped by means of a wiper blade and smooth ink ejection from the nozzle can be ensured over a long term, and an ink jet recorder comprising that ink jet head. SOLUTION: In a color ink jet printer 21, a nozzle plate 9 pasted to the opening side end part of an ejection channel 4 in an ink jet head 24 is formed substantially into a rectangle having four round corner parts 15. Since a wiper blade 46 is not caught by the corner part 15 even if it touches the corner part 15 resiliently, its nozzle face 11 can be wiped off smoothly. Since the nozzle plate 9 is not stripped easily even if it is wiped by means of the wiper blade 46, smooth ink ejection from the nozzle 8 can be ensured over a long term.

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 for ejecting ink from a nozzle to perform a predetermined recording on a sheet or the like, and an ink jet recording apparatus provided with the ink jet head.

[0002]

2. Description of the Related Art Conventionally, an ink jet recording apparatus is well known as a recording apparatus having a relatively simple structure and capable of high speed printing and high quality printing. This ink jet recording apparatus is usually provided with an ink jet head for ejecting ink to perform predetermined recording on a sheet or the like.

Such an ink jet head is usually attached to an actuator in which a plurality of ejection channels are formed, a manifold for distributing and supplying ink to each ejection channel of the actuator, and an opening side end portion of the ejection channel in the actuator. And a nozzle plate.

The actuator is made of a piezoelectric ceramic material such as a piezo element, and the ink supplied from the manifold into each ejection channel is ejected when the volume of the ink is reduced due to the deformation of the actuator, while the ink is ejected when the volume is increased. The ink is again introduced into the ejection channel.

Further, the nozzle plate has a rectangular thin plate shape, and nozzles are formed corresponding to the respective ejection channels.

When the actuator is deformed and driven, ink is ejected as droplets from the nozzles of the nozzle plate attached to the actuator, whereby a predetermined print is formed on the paper or the like.

Further, in such an ink jet head, excess ink is accumulated on the surface of the nozzle plate due to repeated ejection from the nozzle to cause ejection failure, or bubbles are generated in the ink jet head to cause bubbles. In some cases, defective ink including the above may occur. Therefore, the inkjet recording apparatus is usually provided with a wiping device for wiping off excess ink on the surface of the nozzle plate and a purging device for sucking defective ink in the inkjet head.

The wiping device and the purging device are provided so as to be movable back and forth with respect to the inkjet head between a standby area and a recording area of a carriage on which the inkjet head is mounted. For example, the purging device is provided with a cap member that covers the inkjet head, and at the time of purging, the inkjet head is opposed to the cap member and the cap member is advanced to cover the inkjet head with the cap member. By sucking with a pump, the defective ink in the inkjet head is sucked.

Further, for example, the wiping device is provided with a wiper blade capable of elastically contacting the surface of the nozzle plate, and at the time of wiping, the wiper blade is advanced into the moving path of the carriage to record as a waiting area. By making elastic contact with the surface of the nozzle plate that moves between it and the area, excess ink accumulated on the surface of the nozzle plate due to repeated ejection from the nozzles and remaining on the surface of the nozzle plate after being sucked by the purging device The surplus ink etc. is wiped off.

[0010]

However, when the wiping device is wiped, when the wiper blade is elastically contacted with the surface of the nozzle plate which moves between the standby area and the recording area, the wiper formed in a rectangular shape is wiped. The corners of the peripheral edge of the blade are caught by the wiper blade in each case, and eventually the actuator peels off from the actuator.

The present invention has been made in view of such a problem, and an object thereof is to prevent the ink from being easily peeled off even if the surface thereof is wiped by a wiper blade or the like, and to eject a good ink from a nozzle. An object of the present invention is to provide an inkjet head that can be secured for a long period of time, and an inkjet recording apparatus including the inkjet head.

[0012]

In order to achieve the above object, the invention according to claim 1 includes a head main body having an ejection channel for ejecting ink, and a nozzle for ejecting ink from the ejection channel. Has been formed,
In an inkjet head provided with a nozzle plate attached to an opening side end portion of the ejection channel in the head main body, the shape of the nozzle plate is
It is characterized in that it has a plate shape with no corners at the periphery.

According to this structure, since the shape of the nozzle plate is a plate shape with no corners at the peripheral portion, for example, when the excess ink on the surface of the nozzle plate is wiped by the wiper blade, the wiper blade is
The surface of the nozzle plate can be wiped smoothly without being caught by the peripheral edge of the nozzle plate. Therefore, the nozzle plate is not easily peeled off even by wiping the wiper blade, and as a result, good ink ejection from the nozzle can be ensured for a long period of time.

The invention described in claim 2 is the same as claim 1
In the invention described in above, the shape of the nozzle plate is
It is characterized in that it has a rectangular shape with rounded corners.

According to this structure, since the nozzle plate has a rectangular shape, the nozzles can be arranged corresponding to the ejection channels, and the corners thereof are rounded, so that the wiper blade is formed. It is difficult to peel off even by wiping, and good ink ejection from the nozzle can be secured for a long period of time.

The invention described in claim 3 is an ink jet recording apparatus, which is characterized by including the ink jet head described in claim 1 or 2.

Since such an ink jet recording apparatus is equipped with an ink jet head capable of ensuring good ink ejection from the nozzles for a long period of time, it is excellent in durability and good for a long period of time on paper and the like. You can achieve a record.

The invention described in claim 4 is the same as claim 3
In the invention according to, further comprising a wiper blade for wiping the surface of the nozzle plate on the opening side of the nozzle, the peripheral edge portion of both ends of the nozzle plate in the direction orthogonal to the wiping direction of the wiper blade, The feature is that it has no shape.

According to this structure, the wiper blade can satisfactorily wipe excess ink on the surface of the nozzle plate, and at the time of wiping the wiper blade, the wiper blade to be wiped wipes the wiper blade in the wiping direction. The nozzle plate is elastically contacted with the peripheral edges of both ends of the nozzle plate in a direction orthogonal to the nozzle plate, but since the peripheral edges of both ends have a shape without corners, the nozzle plate is hard to be peeled off even by elastic contact of the wiper blade. It is possible to improve the durability of the inkjet head while ensuring good wiping of the blade, and to achieve good recording on a paper or the like for a long period of time.

[0020]

1 is a perspective view showing an embodiment of a color ink jet printer as an ink jet recording apparatus of the present invention. In FIG. 1, the color ink jet printer 21 includes an ink cartridge 22 filled with four color inks of cyan, magenta, yellow, and black, and an ink jet head 24 described in detail below for printing on a paper 23. A carriage 26 on which the ink cartridge 22 and the inkjet head 24 are mounted, and the carriage 2
A drive unit 27 for reciprocating the linear movement of the carriage 6 in a straight line direction, a platen roller 28 extending in the reciprocating movement direction of the carriage 26 and facing the inkjet head 24, a maintenance unit 38, and a waste ink receiving member 37 are provided. .

The drive unit 27 is arranged at the lower end of the carriage 26 and extends parallel to the platen roller 28, a carriage shaft 30, a guide plate 31 arranged at the upper end of the carriage 26 and extends parallel to the carriage shaft 30, and its carriage. Two pulleys 32 and 33 arranged between the shaft 30 and the guide plate 31 at both ends of the carriage shaft 30 and an endless belt 34 stretched between the pulleys 32 and 33 are provided. .

A carriage shaft support portion 35 through which the carriage shaft 30 can be inserted is provided at a lower end portion of the carriage 26, and a guide plate 3 is provided at an upper end portion of the carriage 26.
1 is provided with a guide plate contact portion 36.
An endless belt 34 is joined to the rear side surface of the carriage 26.

The one pulley 32 is connected to the motor 32.
When the pulley 32 is rotated in the forward / reverse direction by the drive of A, the carriage 26 joined to the endless belt 34 is reciprocally moved in the linear direction along the carriage shaft 30 and the guide plate 31 with the forward / reverse rotation of the pulley 32. To be done. As a result, the carriage 26 is mounted with the inkjet head 24 and is movable over a recording area facing the paper 23 and a maintenance area and a flushing area, which will be described later, arranged on both sides of the recording area.

The paper 23 is fed from a paper feed cassette (not shown) provided on the side of the color ink jet printer 21, introduced between the ink jet head 24 and the platen roller 28, and the ink jet head 24.
Predetermined printing is performed by the ink ejected from the sheet, and then the sheet is ejected. In FIG. 1, the paper feed mechanism and the paper discharge mechanism for these papers 23 are omitted.

The maintenance unit 38 is arranged in a maintenance area arranged on one side of the recording area, and has a purging device 39, a wiping device 40 and a storage cap device 41.

The purging device 39 includes a suction cap 42 for tightly covering the nozzle surface 11 of the ink jet head 24, which will be described later, and a pump 4 for sucking and removing the ink in the ink jet head 24 via the suction cap 42.
3, a cam 44 that operates the suction cap 42 and the pump 43, and an ink storage portion 45 that stores defective ink.

When purging the ink jet head 24, first, the nozzle surface 11 of the ink jet head 24 is made to face the suction cap 42 by the movement of the carriage 26, and then the cam 44 is driven by a drive source (not shown) to move the suction cap. By advancing 42, the suction cap 42 is tightly covered on the nozzle surface 11. Then, the pump 43 is driven to suck the defective ink (ink in which bubbles are generated or thickened) in the inkjet head 24 through the suction cap 42. This makes it possible to recover the inkjet head 24. In addition,
The defective ink sucked by the pump 43 is stored in the ink storage portion 45.

The wiping device 40 is arranged adjacent to the purging device 39 in the maintenance area on the recording area side, and is provided with a wiper blade 46 capable of elastically contacting the surface of the nozzle surface 11.

This wiper blade 46 has a nozzle surface 1
It is in the form of a thin rectangular plate that can elastically contact 1 and is made of an elastic material such as ethylene / propylene rubber.

Then, the wiping device 40 uses the cam 44 of the purging device 39 to cause the ink jet head 2 to move.
It is configured to move forward and backward with respect to the movement route of 4,
By advancing the nozzle surface 11 of the inkjet head 24 moving between the recording area and the maintenance area and making the wiper blade 46 elastically contact with the nozzle surface 11, the surface of the nozzle surface 11 is wiped. In addition,
The ink attached to the wiper blade 46 by wiping is
Like the ink sucked by the purging device 39, the ink is stored in the ink storage portion 45.

The storage cap device 41 is arranged adjacent to the purge area 39 on the opposite side of the recording area in the maintenance area, and four storage caps 47 corresponding to the respective ink jet heads 24 are provided in parallel on the casing 48. ing. This casing 48
The engaging protrusion 50 is formed on the outer side of the storage cap 47, and is supported by a guide rod member 49 extending parallel to the moving direction of the carriage 26 so as to be slidable and rotatable. Then, when the carriage 26 moves from the recording area toward the maintenance area, the moving carriage 26 engages with the engaging projection 50 formed on the casing 48, and the storage cap 47 moves. While following the sliding movement, the tilt cam (not shown) rotates in a direction approaching the inkjet head 24 to cover the nozzle surface 11 of the inkjet head 24 in a close contact manner. As a result, each inkjet head 2 that does not perform recording
The nozzle surface 11 of No. 4 is covered with each storage cap 47, so that the evaporation of ink is prevented and the drying of the nozzle surface 11 is prevented. On the other hand, when the carriage 26 moves again in the recording area direction, the storage cap 47 is separated from the inkjet head 24 by the operation reverse to the above.

The waste ink receiving member 37 is arranged in the flushing area on the other side of the recording area, and the nozzle 8 of the ink jet head 24, which will be described later, is provided.
In order to eliminate the clogging of the ink and to remove the air bubbles mixed in the ink in the nozzle 8, the ink ejected preliminarily immediately before the printing operation by the inkjet head 24 is received.

As shown in FIG. 1, the ink jet head 24 is mounted on a carriage 26 and covered and supported by the cover member 1. The cover member 1 has a box shape with an open upper portion, and is formed so as to be able to receive the lower end portions of the respective inkjet heads 24. As shown in FIG. Nozzle plate 9 attached to 24
The openings 12 for exposing the ink are formed corresponding to the respective inkjet heads 24. The lower ends of the inkjet heads 24 are fitted into the openings 12 so that the nozzle plate 9 is exposed downward.

In addition, between the openings 12 of the cover member 1, the groove portions 2 which are convexly curved upward are formed along the direction orthogonal to the arrangement direction of the ink jet heads 24. , Each opening 12 of the cover member 1
The space between the ink jet head 24 and each of the ink jet heads 24 is sealed by a seal material 10 made of an adhesive or the like.

Then, these ink jet heads 2
4, an actuator 3 as a head body in which a plurality of ejection channels 4 are formed, as shown in FIG.
The actuator 3 is provided with a nozzle plate 9 attached to an end portion on the opening side where ink is ejected from each ejection channel 4.

The actuator 3 is interposed between the two channel members 5 having the grooves 13 forming the plurality of ejection channels 4 on one surface and the two channel members 5 so as to cover the plurality of grooves 13. Channel member 5
And a center plate 6 fixed to one surface.

Each channel member 5 has a rectangular shape and is made of a deformable material such as piezoelectric ceramics such as a piezo element. A plurality of grooves 13 for forming the ejection channels 4 are formed in the ink ejection direction. It is formed in parallel with. The groove 13 forms the injection channel 4 between the channel member 5 and the center plate 6 and the side surface of the center plate 6, and the injection channel 4 formed by this is
It is formed in two rows facing each other with the center plate 6 interposed therebetween.

Each of the ejection channels 4 has an ink inlet end 7 into which one end is supplied with ink distributed and supplied from the ink cartridge 22 through a manifold (not shown).
And an ink ejection end 14 for ejecting ink at the other end, and an electrode (not shown) for ejecting ink as droplets from the ink ejection end 14 is provided in each ejection channel 4. There is.

The center plate 6 has a rectangular plate shape,
The channel member 5 is made of a ceramic material and is fixed to both side surfaces thereof.

The nozzle plate 9 is formed of a polyimide thin plate having a thickness of about 100 μm and rounded corners, and the exposed surface on the opposite side of the nozzle plate 9 which is attached to the actuator 3 is the nozzle surface. 11 and the ink ejection end 1 of each ejection channel 4
A plurality of nozzles 8 are formed corresponding to No. 4. More specifically, in the nozzle plate 9, as shown in FIGS. 4 and 5, the four corners 15 at the peripheral edge are formed in a shape having a rounded radius R of 0.5 mm or more. There is. More preferably, the roundness of the corner portion 15 at the peripheral edge is formed to have a circumference radius R of about 1.0 to 1.5 mm.

Next, a series of operations of the color ink jet printer 21 will be described.

First, in the color ink jet printer 21, the ink jet head 24 is arranged in the maintenance area with the storage cap 47 covered before the printing operation is started. 23 is fed between the platen roller 28 and the ink jet head 24, the storage cap 47 is separated from the ink jet head 24, and the carriage 26 moves to move the ink jet head 24 to a recording area to perform a predetermined recording. Predetermined recording is performed on the paper 23 by reciprocating while ejecting ink based on the data.

In this printing operation, the ink supplied from each ink cartridge 22 is distributed and supplied from the manifold (not shown) into the ejection channels 4 formed in two rows in the actuator 3 and from the ink inlet end 7. To be done. Then, each ejection channel 4 changes the volume of the ejection channel 4 due to the deformation driving of the actuator 3 in response to an ejection pulse signal from a flexible wiring board (not shown), so that the supplied ink is ejected at the ink ejection end 14 when the volume is reduced. Droplets are ejected as droplets from the nozzle plate 9 through the nozzles 8, and when the volume is increased, the droplets are introduced into the ejection channel 4 again from the ink inlet end 7. By repeating such an operation, a predetermined print is formed on the paper 23.

When the printing operation of the ink jet head 24 is completed, the carriage 26 moves from the recording area to the maintenance area, and each storage cap 47 covers the nozzle surface 11 of each ink jet head 24 again.

On the other hand, when a purging operation is instructed to the ink jet head 24 artificially or at predetermined intervals, the carriage 26 causes the suction cap 4 to move the specific ink jet head 24 for which the purging operation is instructed.
Move to a position facing 2. Next, the cam 44 is driven by a drive source (not shown), the suction cap 42 is advanced, and the nozzle surface 11 of the inkjet head 24 is tightly covered with the suction cap 42. After that, the pump 43 is driven to drive the nozzle 8 to the inkjet head 2
Purging is performed by sucking the ink in the nozzle 4.

When the purging operation is completed, the suction cap 42 is retracted while the wiper blade 46 is retracted.
To move the carriage 26 to move the inkjet head 24, which has been purged, to the wiper blade 4
The nozzle surface 11 of the ink jet head 24 is wiped off by the wiper blade 46 by moving the nozzle surface 11 in a direction crossing 6.

Further, when ink is repeatedly ejected from the nozzle 8 in the printing operation, excess ink may be accumulated on the nozzle surface 11 to cause ejection failure. Therefore, the wiper blade 46 is advanced at regular intervals. At the same time, the carriage 26 moves the inkjet head 24 in a direction that traverses the wiper blade 46, and the nozzle surface 11 of the inkjet head 24 is wiped off by the wiper blade 46.

In the color ink jet printer 21, since the nozzle plate 9 is formed in a substantially rectangular plate shape, the nozzles 8 can be formed in two rows corresponding to the ejection channels 4. However, since each corner 15 is rounded, the nozzle plate 9
When the excess ink on the surface of the nozzle surface 11 of the nozzle plate 9 is wiped by the wiper blade 46, as shown in FIG. 3, the wiper blade 46 moves the nozzle plate 9 in the direction orthogonal to the wiping direction of the wiper blade 46. Even if the peripheral edge portions of both ends are elastically contacted, the corner portion 15 is not caught and the surface of the nozzle surface 11 can be wiped smoothly. Therefore, the nozzle plate 9 is not easily peeled off even by wiping the wiper blade 46, and as a result, good ink ejection from the nozzle 8 can be ensured for a long period of time.

Since the color ink jet printer 21 is provided with the ink jet head 24 having such a nozzle plate 9, it has excellent durability.
Good recording can be achieved for a long time on the paper 23 or the like.

In the above description, each corner portion 15 of the peripheral edge portion of the nozzle plate 9 is formed by an arc having a predetermined circumferential radius. However, the shape of the nozzle plate 9 has no peripheral edge portion. If it is a shape, for example, FIG.
Alternatively, as shown in FIG. 7, each corner 15 may be formed in an elliptical shape.

[0051]

As described above, according to the invention described in claim 1, the nozzle plate is hard to be peeled off even by wiping the wiper blade, and as a result, good ink ejection from the nozzle can be achieved for a long time. Can be secured.

According to the second aspect of the present invention, the nozzles can be arranged corresponding to the ejection channels, but they are hard to come off even by wiping the wiper blade,
Good ejection of ink from the nozzles can be ensured for a long period of time.

According to the third aspect of the invention, the durability is excellent, and good recording can be achieved on a sheet or the like for a long period of time.

According to the fourth aspect of the present invention, while ensuring good wiping of the wiper blade, the durability of the ink jet head is improved, and good recording is achieved for a long time on paper or the like. You can

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a color inkjet printer as an inkjet recording apparatus of the present invention.

FIG. 2 is a perspective view of an inkjet head of the color inkjet printer shown in FIG.

FIG. 3 is an enlarged side sectional view of a main part of the inkjet head and the nozzle plate shown in FIG.

4 is a front view of a nozzle plate of the inkjet head shown in FIG.

5 is an enlarged view of a peripheral portion of the nozzle plate shown in FIG.

FIG. 6 is a front view of another embodiment of the nozzle plate of the inkjet head shown in FIG. 2 (corner portion having an elliptical shape).

FIG. 7 is a front view of another embodiment of the nozzle plate of the inkjet head shown in FIG. 2 (corner portion having an elliptical shape).

[Explanation of symbols]

3 actuators 4 injection channels 8 nozzles 9 nozzle plate 15 corners 21 color inkjet printer 24 inkjet head 46 wiper blade

Claims (4)

[Claims] 1. A head body having an ejection channel for ejecting ink and a nozzle for ejecting ink from the ejection channel are formed, and the head body is attached to an end portion on the opening side of the ejection channel in the head body. An ink jet head comprising a nozzle plate having a nozzle plate, wherein the nozzle plate has a plate shape with no corners at its peripheral edge. 2. The ink jet head according to claim 1, wherein the nozzle plate has a rectangular shape with rounded corners. 3. An ink jet recording apparatus comprising the ink jet head according to claim 1 or 2. 4. A wiper blade for wiping a surface of the nozzle plate on the opening side of the nozzle is further provided, and edges of both ends of the nozzle plate in a direction orthogonal to a wiping direction of the wiper blade have no corners. The inkjet recording device according to claim 3, wherein the inkjet recording device has a shape.