JP3909948B2 - Recording head - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a recording head that forms an image on a recording medium by ejecting ink drops according to an image signal toward the recording medium, and in particular, ejects ink drops by the pressure of ultrasonic waves emitted from a piezoelectric element. The present invention relates to a recording head that forms an image on a recording medium.
[0002]
[Prior art]
Conventionally, as a recording head for ejecting ink droplets corresponding to an image signal toward a recording medium to form dots by the ink droplets on the recording medium and forming a desired image on the recording medium, ultrasonic waves are applied to the ink liquid surface. Ink droplets that are focused on and ejected using the pressure of ultrasonic waves are known.
[0003]
In general, a recording head using this type of ultrasonic wave has a plurality of piezoelectric elements for generating ultrasonic waves corresponding to image signals arranged in parallel at the bottom of an ink tank containing ink, and is separated from the piezoelectric element. A slit extending in the direction in which the piezoelectric elements are arranged along the liquid surface is formed. The width of the slit is set to about 100 μm to 500 μm for the purpose of preventing ink evaporation and stabilizing the ink surface. The ultrasonic waves generated from each piezoelectric element are focused on a plurality of discharge points along the center of the slit, and ink droplets are discharged from the desired discharge points by the pressure of the ultrasonic waves.
[0004]
[Problems to be solved by the invention]
In the conventional recording head as described above, since the ink droplets are ejected from a plurality of ejection points having liquid levels connected along the slit, the diameter of the ejected ink droplet and the ejection direction of the ink droplet can be stabilized. difficult. In particular, when dust or debris (paper dust or the like) generated from the recording medium adheres in the vicinity of the slit and a stable liquid surface cannot be formed at the slit, the ink droplet diameter becomes unstable and the ink droplet There arises a problem that the discharge direction becomes unstable.
[0005]
For this reason, in a conventional recording head, a cleaning member such as a sponge is slidably brought into contact with the upper surface of the recording head in which the slit is formed during standby for the recording operation, thereby cleaning the upper surface of the head near the slit. However, at this time, there is a problem that the ink in the recording head is undesirably sucked up by the cleaning member through the slit, and the ink is wasted. Further, when the cleaning member is brought into sliding contact with the upper surface of the head, the ink is undesirably attached to the upper surface of the head in the vicinity of the slit, and the attached ink is connected to the ink in the head through the slit. The surface becomes unstable and the ink droplet ejection direction becomes unstable.
[0006]
The present invention has been made in view of the above points, and an object of the present invention is to provide a recording head capable of satisfactorily cleaning the upper surface of the head without unnecessarily wasting ink and obtaining stable recording characteristics. There is.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the present invention The recording head has an upper surface formed with a slit extending in a first direction crossing the conveying direction of the recording medium along a horizontal plane spaced a predetermined distance below the recording medium conveyed in a substantially horizontal direction. A storage container for storing the recording liquid so that the liquid level is held by the storage container, and the recording liquid provided adjacent to the storage container and connected to the storage container via a supply pipe to store the recording liquid to be supplied to the storage container A first position for supplying the recording liquid from the tank to the receiving container through the supply pipe and holding the liquid level at the slit, and recording from the receiving container to the tank through the supply pipe. Lifting means for raising and lowering the tank relative to the storage container between the second position for recovering a part of the liquid and lowering the liquid level held by the slit; and the storage container On the bottom of the first A sound wave generating means extending along the direction and generating a sound wave propagating through the recording liquid toward the slit based on an image signal, and a layer on the sound wave generating means are provided and exposed to the recording liquid. A plurality of grooves extending in the first direction, and the second direction orthogonal to the first direction toward the center of the slit by the action of the grooves. And a cleaning means for cleaning the foreign matter adhering to the vicinity of the slit by sliding the cleaning member on the upper surface of the container. And the second position where the tank is lowered by the elevating means is set to a height at which the recording liquid is not recovered from the plurality of grooves of the sound wave focusing means, In the cleaning means, the tank is lowered to the second position by the elevating means, a part of the recording liquid supplied to the storage container is collected into the tank, and the liquid level held in the slit is lowered. In this state, a cleaning member is brought into sliding contact with the upper surface of the storage container to clean the upper surface.
[0010]
In addition, this invention Notation According to the recording head, the height position of the tank is adjusted by detecting the height of the liquid level of the recording liquid stored in the tank and operating the elevating means.
[0011]
In addition, this invention Notation The recording head has an upper surface formed with a slit extending in a first direction crossing the conveyance direction of the recording medium along a horizontal plane spaced a predetermined distance below the recording medium conveyed in a substantially horizontal direction. A storage container for storing the recording liquid so that the liquid level is held by the storage container, and the recording liquid provided adjacent to the storage container and connected to the storage container via a supply pipe to store the recording liquid to be supplied to the storage container A first position for supplying the recording liquid from the tank to the receiving container through the supply pipe and holding the liquid level at the slit, and recording from the receiving container to the tank through the supply pipe. Lifting means for raising and lowering the tank relative to the storage container between the second position for recovering a part of the liquid and lowering the liquid level held by the slit; and the storage container On the bottom of the first A sound wave generating means extending along the direction and generating a sound wave propagating through the recording liquid toward the slit based on an image signal, and being laminated on the sound wave generating means and exposed to the recording liquid. A plurality of grooves extending in the first direction on the upper surface, and the sound waves generated by the sound wave generating means are orthogonal to the first direction toward the center of the slit by the action of the grooves. A sound wave converging means for converging in the second direction and ejecting the recording liquid from the slit toward the recording medium, and a foreign material adhering to the vicinity of the slit are cleaned by sliding a cleaning member on the upper surface of the container. A second position where the tank is lowered by the elevating means. The recording liquid filled between the upper surface of the sound wave focusing means and the upper surface of the container is The cleaning fluid is set at a height that is separated from the recording liquid stored in the tank by the air flowing in through the tank, and the cleaning device lowers the tank to the second position by the elevating device. In a state where the liquid is divided, a cleaning member is slidably brought into contact with the upper surface of the storage container to clean the upper surface.
[0012]
Furthermore, this invention Notation The recording head has an upper surface formed with a slit extending in a first direction crossing the conveyance direction of the recording medium along a horizontal plane spaced a predetermined distance below the recording medium conveyed in a substantially horizontal direction. A storage container for storing the recording liquid so that the liquid level is held by the storage container, and the storage container via a supply pipe provided adjacent to the storage container and connected to a hole formed in the bottom of the storage container A tank that stores the recording liquid to be supplied to the storage container, a first position that supplies the recording liquid from the tank to the storage container via the supply pipe and holds the liquid level at the slit; The tank is placed in the storage container between a second position where a part of the recording liquid is recovered from the storage container to the tank via the supply pipe and the liquid level held by the slit is lowered. Move up and down relatively A lowering means and a sound wave that extends along the first direction and is propagated through the recording liquid toward the slit at a position outside the hole to which the supply pipe is connected at the bottom of the container. And a plurality of grooves extending in the first direction on the upper surface exposed to the recording liquid, and provided on the upper surface exposed to the recording liquid. The sound wave generated by the generating means is focused toward the center of the slit by the action of the groove in a second direction orthogonal to the first direction, and the recording liquid is discharged from the slit toward the recording medium. A cleaning means for cleaning the foreign matter adhering to the vicinity of the slit by sliding a cleaning member on the upper surface of the container, and the hole formed in the bottom of the container is The second position where the tank is lowered by the elevating means is formed between the upper surface of the sound wave focusing means and the upper surface of the receiving container. The recording liquid is set to a height that is separated from the recording liquid stored in the tank by the air flowing between the holes through one end of the slit, and the cleaning means In a state where the tank is lowered to the second position by the elevating means and the recording liquid is divided, the upper surface is cleaned by sliding the cleaning member on the upper surface of the storage container.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 shows a recording head 1 of the present invention together with its peripheral members. A platen roller 2 is disposed at a position facing the upper surface 1a of the recording head 1 via a predetermined gap. The platen roller 2 is rotated in a predetermined direction while the recording paper P is wound around it. As a result, the recording paper P is conveyed in a direction substantially orthogonal to the rotation axis of the platen roller 2 while maintaining a certain gap with respect to the head upper surface 1a.
[0014]
A slit 10 is formed on the upper surface 1 a of the recording head 1 so as to extend in a direction transverse to the conveyance direction of the recording paper P, that is, in parallel with the rotation axis of the platen roller 2. An ink tank 4 that stores ink to be supplied to the recording head 1 is disposed at a position adjacent to the recording head 1. The ink tank 4 is connected to the recording head 1 via the supply tube 6.
[0015]
FIG. 2 schematically shows a perspective view of the recording head 1 in a partially disassembled state.
The recording head 1 has a rectangular plate-like substrate 12 having an upper surface 12a extending substantially horizontally. On the upper surface 12a of the substrate 12, a plurality of lead electrodes 13 extending in the sub-scanning direction (arrow Y direction in the figure) of the recording head 1 are formed in an array at a predetermined pitch. A piezoelectric element 15 for generating ultrasonic waves is provided on the upper surface 12 a of the substrate 12 through these extraction electrodes 13. In addition, an ink supply hole 12b for connecting the supply tube 6 is formed in a portion of the substrate 12 where the piezoelectric element 15 is not mounted.
[0016]
The piezoelectric element 15 has a thickness of about 50 μm made of a plurality of individual electrodes 14 (see FIG. 3) arranged in an array extending in the sub-scanning direction of the recording head 1 and a lead titanate piezoelectric ceramic having a relative dielectric constant of 200. The piezoelectric body 16 and the common electrode 17 are sequentially stacked in a direction away from the base material 12. Each individual electrode 14 of the piezoelectric element 15 is provided corresponding to the lead electrode 13 formed on the upper surface 12a of the substrate 12, and has a length of, for example, 5.0 mm in the sub scanning direction and is orthogonal to the sub scanning direction. It has a width of 60 μm in the main scanning direction (arrow X direction in the figure) and is formed at a pitch of 25 μm in the main scanning direction. The common electrode 17 has a length of 2.0 mm in the sub-scanning direction, for example, and is provided so as to cover all the individual electrodes.
[0017]
Each individual electrode 14 of the piezoelectric element 15 and each extraction electrode 13 on the base material 12 are overlapped and aligned, and the piezoelectric element 15 and the base material 12 are pressure-bonded via an epoxy resin so that each electrode is electrically connected. Connected to. Each extraction electrode 13 is connected to a driving IC 19 for driving the piezoelectric element 15 via a bonding wire 18. The common electrode 17 is connected to a common terminal (not shown) of the drive IC 19. Further, a signal (not shown) for outputting a burst signal (hereinafter also referred to as a burst wave) based on an image signal input from a signal source (not shown) to each individual electrode 14 to the drive IC 19 connected to each lead electrode 13. A processing unit is connected.
[0018]
On the piezoelectric element 15, a substantially rectangular plate-shaped lens member 20 for focusing the ultrasonic wave generated from the piezoelectric element 15 on the center of the slit 10 formed on the upper surface 1 a of the recording head 1 is laminated. . A plurality of lens grooves 20 a extending in the main scanning direction based on the Fresnel zone theory are formed on the upper surface of the lens member 20. The plurality of lens grooves 20a are formed symmetrically with respect to the center line in the sub-scanning direction of the lens member 20, and the depth of each lens groove 20a is (2n + 1) of the wavelength of the ultrasonic wave propagating through the ink. / 4 times (n is an integer of 0 or more).
[0019]
An ink chamber member 11 is provided on the upper surface 12 a of the base 12 so as to cover the ink supply hole 12 b together with the piezoelectric element 15 and the lens member 20. The upper surface of the ink chamber member 11 forms the upper surface 1 a of the recording head 1, and the slit 10 having a width of 300 μm in the sub-scanning direction is formed on the upper surface of the ink chamber member 11. The height of the ink chamber member 11 is 2.5 mm from the bottom of the lens groove 20a to the slit 10 so that the ultrasonic focusing position by the lens member 20 exactly matches the height position of the slit 10. Was set to be. For example, an epoxy resin in which alumina powder is dispersed is used as the ink chamber member 11 together with the lens member 20 as a material having an acoustic impedance close to the square root of the product of the acoustic impedance of the piezoelectric body 16 and the acoustic impedance of the ink. It was.
[0020]
Next, the manufacturing process of the recording head 1 described above will be described.
First, prior to assembling the recording head 1, an ink chamber member 11 and a lens member 20 are prepared in which a plurality of extraction electrodes 13 are formed in advance on the upper surface 12 a of the substrate 12 and molded into a predetermined shape. The extraction electrode 13 is formed by forming Ti / Au on the upper surface 12a of the substrate 12 by sputtering and etching it into a predetermined pattern.
[0021]
The ink chamber member 11 and the lens member 20 have an ultrasonic velocity of 3 × 10 that propagates through the members. ^Three Alumina powder adjusted to a mixing ratio so as to be m / s is mixed with an epoxy resin and molded to have a density of 2.20 × 10. ^Three kg / m ^Three , Speed of sound 2.95 × 10 ^Three m / s was obtained. The lens member 20 was molded so that the thickness of the bottom surface was 45 μm.
[0022]
Then, Ti / Au electrodes are formed on both surfaces of the piezoelectric body 16 made of a lead titanate piezoelectric ceramic having a relative dielectric constant of 200, a thickness of about 0.5 mm, and a width of 5 mm in the sub-scanning direction. At this time, an electrode having a thickness of 0.05 μm, which will later become an individual electrode 14, is formed on one surface of the piezoelectric body 16, and an electrode for polarization treatment is formed on the other surface with a thickness of 0.2 μm. .
[0023]
Next, an electric field of 3 kV / mm is formed between the electrodes formed on both surfaces of the piezoelectric body 16, and the piezoelectric body 16 is polarized. Then, one electrode is etched to form a plurality of individual electrodes 14 having a width of 60 μm and an inter-electrode pitch of 25 μm. And the piezoelectric material 16 is laminated | stacked via the adhesive agent on the upper surface 12a of the base material 12 so that each individual electrode 14 may be piled up on the extraction electrode 13 previously formed on the base material 12, and both electrodes Is pressed and pressure-bonded.
[0024]
In this manner, the piezoelectric body 16 is polished together with the polarization electrodes formed on the upper surface of the piezoelectric body in a state where the piezoelectric body is bonded onto the substrate 12. At this time, polishing is performed so that the thickness of the piezoelectric body 16 becomes 50 μm. Further, a common electrode 17 made of Al is formed on the polished surface of the piezoelectric body 16 to a thickness of 0.3 μm by sputtering. The width of the common electrode 17 in the sub-scanning direction is set to 2.0 mm.
[0025]
Then, the lens member 20 prepared in advance is laminated on the piezoelectric element 15 formed as described above, and is bonded via an adhesive.
Further, the ink chamber member 11 is attached on the substrate 12 so as to cover the piezoelectric element 15 and the lens member 20. At this time, the ink chamber member 11 is positioned so that the center of the slit 10 of the ink chamber member 11 coincides with the center of the lens member 20 in the sub-scanning direction, and the ink chamber member 11 is bonded onto the substrate 12. In addition, before the ink chamber member 11 is mounted on the substrate 12, ink is supplied to the upper surface of the lens member 20 via a brush or the like, and the plurality of lens grooves 20a are wetted with ink in advance.
[0026]
Finally, a driving IC 19 for supplying a driving voltage to the piezoelectric element 15 is mounted on the upper surface 12a of the substrate 12, and the individual electrodes 14 and the common electrode 17 of the piezoelectric element 15 are bonded via bonding wires 18, The assembly of the recording head 1 is completed.
[0027]
Here, the driving principle of the recording head 1 will be described with reference to FIG.
A burst wave output from a signal processing unit (not shown) is formed as a sine wave having a relatively high frequency close to a resonance frequency determined by the thickness of the piezoelectric body 16 and the like, and the wave number calculated by the signal processing unit, It has a burst width determined by this wave number.
[0028]
In this embodiment, eight adjacent individual electrodes 14 are made into one group, and burst waves having the same wave number are simultaneously applied to these eight individual electrodes 14 to eject one ink droplet. At this time, among the burst waves having the same wave number, a zero-phase burst wave and a π-phase burst wave whose phases are shifted from each other by 180 ° are prepared, and burst waves having different phases in the order of 0π0000π0 are given to the arrangement direction of the eight electrodes. I did it. Thereby, an ultrasonic wave can be focused toward the center of the electrode arrangement direction, and one ink droplet can be ejected from the center position of the eight electrodes. At this time, focusing of sound waves in the sub-scanning direction is caused by the action of the lens groove 20a of the lens member 20.
[0029]
As described above, when ink droplets are ejected with eight individual electrodes 14 as one group, the ejection interval of ink droplets that can be ejected simultaneously corresponds to eight electrodes. For this reason, in order to eject ink droplets for one line along the main scanning direction, the groups of the individual electrodes 14 that give the same burst wave are scanned in the main scanning direction while shifting one electrode at a time. It is necessary to give eight burst waves to each of the electrodes.
[0030]
Next, the operation of the recording head 1 described above will be described with reference to FIGS. 4 is a cross-sectional view in the main scanning direction showing the state of ink inside the recording head 1 during the recording operation, and FIG. 5 is a main scanning showing the state of ink inside the recording head 1 during the non-recording operation, that is, during the cleaning operation. FIG. 6 is a sectional view in the sub-scanning direction mainly showing a cleaning mechanism for cleaning the upper surface 1a of the recording head 1. FIG.
[0031]
As shown in FIG. 4, during the recording operation, the ink stored in the ink tank 4 is supplied into the recording head 1 through the ink supply tube 6 and the ink supply hole 12b. At this time, in order to obtain good recording characteristics, it is important that the ink level is always stably held at the upper end of the slit 10. In order to stably form the ink level at the upper end of the slit 10, the height position of the ink tank 4 connected to the recording head 1 is adjusted via the supply tube 6, and the ink enters the head 1 with hydrostatic pressure. Supplied. In other words, by always keeping the difference Δh between the height of the upper end of the slit 10 and the height of the ink liquid level in the ink tank 4, the ink liquid level can always be stably formed at the upper end of the slit 10.
[0032]
An elevating mechanism 30 for adjusting the height position of the ink tank 4 to make Δh constant is wound around a pair of rollers 31 and 32 that are spaced apart in the vertical direction, and the pair of rollers 31 and 32. A lifting belt 34 that is stretched, a drive motor (not shown) that rotationally drives one roller in both forward and reverse directions to make the lifting belt 34 run endlessly, and a liquid level of ink stored in the ink tank 4. And an ink sensor 36 for detecting an appropriate height position of the ink tank 4. The ink sensor 36 has a pair of electrodes having end portions that come into contact with ink, and detects that the ink liquid level is detected by detecting that these electrodes are conducted through the ink.
[0033]
The ink tank 4 is fixed to the elevating belt 34 and is moved in the vertical vertical direction by the traveling of the elevating belt 34. At this time, when the ink sensor 36 detects the ink level in the ink tank 4, the elevating mechanism 30 is stopped, and the ink tank 4 is stopped at a predetermined height position. That is, the end of the electrode of the ink sensor 36 is fixed in advance at a predetermined height, and if the ink tank is stopped when the ink sensor 36 detects the liquid level, the ink sensor 36 is accommodated in the ink tank 4. The ink level can always be kept at the same height. Thereby, Δh can always be kept constant.
[0034]
When ink is consumed according to the recording operation, the ink tank 4 is gradually raised so as to correct the drop in the ink liquid level, and the liquid level of the ink stored in the ink tank 4 is always the same. Adjusted to height.
[0035]
By the way, if the recording operation is continued in such a state that the ink level is stably formed at the upper end of the slit 10 as described above, the time during which the slit 10 is exposed to the outside air becomes long and passes over the slit 10. The number of recording papers P increases, and ink adheres to the vicinity of the slits or paper dust or dust adheres. As described above, when paper dust or dust adheres to the vicinity of the slit, the ink level cannot be stably formed at the upper end of the slit 10, the ink droplet ejection direction becomes unstable, or the diameter of the ink droplet This will cause problems such as being not constant. For this reason, when the recording operation is executed continuously for a certain time, it is necessary to temporarily interrupt the recording operation and clean the upper surface 1a of the recording head near the slit 10.
[0036]
However, as described above, when the upper surface 1a of the recording head 1 is to be cleaned while the ink liquid level is formed at the upper end of the slit 10, for example, a sponge or the like is slidably contacted with the head upper surface 1a as a cleaning member. As a result, the ink in the recording head 1 is undesirably sucked up through the slit 10, and the ink is wasted and the running cost is increased.
[0037]
Further, when ink is sucked up by the sponge in this way, the sucked ink is undesirably attached to the upper surface 1a of the recording head 1 by the sliding contact of the sponge, and the attached ink is connected to the ink in the head 1 and the ink. The liquid surface cannot be stably formed at the upper end of the slit 10, causing the above-described problems and deteriorating the recording characteristics.
[0038]
For this reason, in this embodiment, before the cleaning operation is performed, the ink tank 4 is lowered by a predetermined amount, and the ink level that has been filled up to the upper end of the slit 10 is lowered to a predetermined level. . FIG. 5 shows a state in which the ink tank 4 is lowered and a part of the ink supplied into the recording head 1 is collected to the ink tank 4 side.
[0039]
In this way, by collecting a part of the ink supplied into the recording head 1, the liquid level of the ink filled up to the upper end of the slit 10 is lowered, and in this state, a cleaning member such as a sponge is moved to the head upper surface 1a. The ink is not sucked up by the sponge even if it is slidably contacted with the ink, and the waste of the ink is prevented. Further, if at least the liquid level is lowered, even if ink is sucked up undesirably through the slit 10, it is possible to prevent a large amount of ink from being wasted only by a small amount of ink being wasted. The ink can be prevented from undesirably adhering to the upper surface 1a of the recording head 1 due to the sliding contact of the sponge.
[0040]
Actually, when the ink tank 4 is lowered and ink in the recording head 1 starts to be sucked out through the supply tube 6 and the ink supply hole 12b, first, the ink tank 4 is positioned above the ink supply hole 12b. Air is sucked from the end portion 10a of the slit 10, and the ink connection is broken at this portion. In other words, in the present embodiment, the length of the lens member 20 in the main scanning direction is sufficiently long with respect to the distance from the lens member 20 to the upper surface of the ink chamber member 11, and therefore, from the left end of the lens member 20 in the drawing. If the slit end portion 10a is extended to a position close to the ink supply hole 12b side, the capillary force of the ink accumulated on the lens member 20 is superior to the force to join the ink at the slit end portion 10a. The ink is divided at the portion.
[0041]
In this way, once the ink connection is broken, the ink accumulated above the lens member 20 remains in place without being collected by its own surface tension. In other words, the position of the ink supply hole 12b and the slit end 10a are brought close to each other, more specifically, the position of both is set so that the slit end 10a is located above the ink supply hole 12b. The state of 5 can be maintained.
[0042]
As a result, even if the ink is sucked up by the cleaning member through the slit 10, the ink is divided at the portion of the slit end 10 a, so that the ink contained in the ink tank 4 is sucked up. There is no.
[0043]
In addition, since the ink can be left on the lens member 20 as described above, even the ink that has entered the lens groove 20a can be prevented from being collected. That is, since the depth and width of the lens groove 20a are about several tens of μm, once ink is collected from the lens groove 20a, the inside of the lens groove 20a is used by using a brush or the like as in assembling the head. The ink must be forcibly supplied. If the ink cannot be normally supplied into the lens groove 20a, air may enter the lens groove 20a and the ultrasonic waves will be absorbed undesirably, and the ultrasonic waves will not be transmitted normally. Will not be discharged.
[0044]
Therefore, when collecting ink from the recording head 1, it is important to leave the ink in the lens groove 20a of the lens member 20 as in the present embodiment. For this reason, in this embodiment, in order to leave ink on the lens member 20, the slit end 10a is extended to above the ink supply hole 12b.
[0045]
As shown in FIG. 6, the cleaning mechanism 40 for cleaning the upper surface 1 a of the recording head 1 is wound around a pair of rollers 41 and 42 that are spaced apart from each other in the sub-scanning direction of the recording head 1 and a pair of rollers 41 and 42. The belt 44 is rotated and wound and stretched, the cleaning unit 45 fixed to the belt 44 and opposed to the upper surface 1a of the recording head 1, and one of the rollers is rotated to rotate the belt 44 in the sub-scanning direction. A drive motor (not shown) that is allowed to travel.
[0046]
The cleaning unit 45 is a pair of sponges as a cleaning member disposed in contact with both ends of the head upper surface 1a in the sub-scanning direction in a state where the cleaning unit 45 is moved to the closed position indicated by the solid line in the figure facing the upper surface 1a of the recording head 1. 46, 48. The cleaning unit 45 is moved to a retracted position indicated by a broken line in the drawing during a normal recording operation in which no cleaning operation is performed. At the end of the recording operation, it is moved to the closing position.
[0047]
Thus, when the belt 44 is run and the cleaning unit 45 is moved in the sub-scanning direction, the pair of sponges 46 and 48 are brought into sliding contact with the upper surface 1a of the recording head 1 and attached to the head upper surface 1a in the vicinity of the slit 10. Paper dust and dust are cleaned. When the cleaning unit 45 is moved to the closing position, the upper surface 1a of the recording head 1 is closed by the cleaning unit 45, so that ink evaporation can be suppressed and dust can be prevented from adhering to the vicinity of the slit.
[0048]
In addition, this invention is not limited to embodiment mentioned above, A various deformation | transformation is possible within the scope of this invention. For example, in the above-described embodiment, an example in which a sponge is used as the cleaning member has been described. However, a brush or the like can be used instead of the sponge.
[0049]
【The invention's effect】
As described above, since the recording head of the present invention has the above-described configuration and operation, the upper surface of the head can be cleaned well without unnecessarily wasting ink, and stable recording characteristics can be obtained. Obtainable.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a recording head and its peripheral members according to an embodiment of the present invention.
FIG. 2 is an exploded perspective view in which the recording head of FIG. 1 is partially disassembled.
FIG. 3 is an operation explanatory diagram for explaining the principle of ink droplet ejection in the recording head of FIG. 1;
FIG. 4 is a schematic diagram illustrating a state of a recording head during a recording operation.
FIG. 5 is a schematic diagram illustrating a state of a recording head during a non-recording operation.
FIG. 6 is a view for explaining the operation of a recording head cleaning mechanism;
[Explanation of symbols]
1 ... recording head,
1a: top surface,
2 ... Platen roller,
4 ... ink tank,
6 ... supply tube,
10 ... Slit,
11: Ink chamber member,
12 ... base material,
12b ... ink supply hole,
13 ... extraction electrode,
14: Individual electrodes,
15 ... piezoelectric element,
16 ... piezoelectric body,
17 ... Common electrode,
18 ... bonding wire,
19 ... Drive IC,
20 ... Lens member,
20a ... lens groove,
30 ... Lifting mechanism,
40. Cleaning mechanism,
P: Recording paper.

Claims (4)

An upper surface formed with a slit extending in a first direction across the conveying direction of the recording medium along a horizontal plane spaced by a predetermined distance below the recording medium conveyed in a substantially horizontal direction; A storage container for storing the recording liquid to be held;
A tank that is provided adjacent to the storage container, communicates with the storage container via a supply pipe, and stores recording liquid to be supplied to the storage container;
A first position for supplying the recording liquid from the tank to the storage container via the supply pipe and holding the liquid level at the slit; and a part of the recording liquid from the storage container to the tank via the supply pipe And a second position for lowering the liquid level held in the slit and raising and lowering means for raising and lowering the tank relative to the container,
A sound wave generator extending along the first direction at the bottom of the container and generating a sound wave propagating through the recording liquid toward the slit based on an image signal;
A plurality of grooves provided in a stacked manner on the sound wave generating means and extending in the first direction exposed to the recording liquid, and the sound waves generated by the sound wave generating means are generated by the action of the grooves. A sound wave converging means for converging in a second direction orthogonal to the first direction toward the center of the slit, and discharging a recording liquid from the slit toward the recording medium;
Cleaning means for cleaning foreign matter adhering to the vicinity of the slit by sliding a cleaning member on the upper surface of the container; and
The second position where the tank is lowered by the elevating means is set to a height at which the recording liquid is not recovered from the plurality of grooves of the sound wave focusing means,
In the cleaning means, the tank is lowered to the second position by the elevating means, a part of the recording liquid supplied to the storage container is collected into the tank, and the liquid level held in the slit is lowered. A recording head, wherein a cleaning member is slidably brought into contact with the upper surface of the storage container in a state where the upper surface is cleaned.   2. The recording head according to claim 1, wherein the height position of the tank is adjusted by detecting the height of the recording liquid stored in the tank and operating the elevating means. . An upper surface formed with a slit extending in a first direction across the conveying direction of the recording medium along a horizontal plane spaced by a predetermined distance below the recording medium conveyed in a substantially horizontal direction; A storage container for storing the recording liquid to be held;
A tank that is provided adjacent to the storage container, communicates with the storage container via a supply pipe, and stores recording liquid to be supplied to the storage container;
A first position for supplying the recording liquid from the tank to the storage container via the supply pipe and holding the liquid level at the slit; and a part of the recording liquid from the storage container to the tank via the supply pipe And a second position for lowering the liquid level held in the slit and raising and lowering means for raising and lowering the tank relative to the container,
A sound wave generator extending along the first direction at the bottom of the container and generating a sound wave propagating through the recording liquid toward the slit based on an image signal;
A plurality of grooves extending in the first direction are provided on the upper surface exposed to the recording liquid and provided on the sound wave generating means, and the sound waves generated by the sound wave generating means are operated by the grooves. A sound wave converging means for converging in a second direction orthogonal to the first direction toward the center of the slit and discharging a recording liquid from the slit toward the recording medium;
Cleaning means for cleaning foreign matter adhering to the vicinity of the slit by sliding a cleaning member on the upper surface of the container; and
The second position where the tank is lowered by the elevating means is that the recording liquid filled between the upper surface of the sound wave converging means and the upper surface of the container is caused by the air flowing in through the slit. It is set to a height that is separated from the recording liquid stored in the tank,
The cleaning means cleans the upper surface by sliding the cleaning member against the upper surface of the storage container in a state where the tank is lowered to the second position by the elevating means and the recording liquid is divided. Recording head. An upper surface formed with a slit extending in a first direction across the conveying direction of the recording medium along a horizontal plane spaced by a predetermined distance below the recording medium conveyed in a substantially horizontal direction; A storage container for storing the recording liquid to be held;
A tank that is provided adjacent to the storage container, communicates with the storage container via a supply pipe connected to a hole formed in the bottom of the storage container, and stores a recording liquid supplied to the storage container;
A first position for supplying the recording liquid from the tank to the storage container via the supply pipe and holding the liquid level at the slit; and a part of the recording liquid from the storage container to the tank via the supply pipe And a second position for lowering the liquid level held in the slit and raising and lowering means for raising and lowering the tank relative to the container,
A sound wave that extends along the first direction and is propagated through the recording liquid toward the slit is formed as an image signal at a position at the bottom of the storage container and out of the hole to which the supply pipe is connected. Sound wave generating means for generating based on;
A plurality of grooves extending in the first direction are provided on the upper surface exposed to the recording liquid and provided on the sound wave generating means, and the sound waves generated by the sound wave generating means are operated by the grooves. A sound wave converging means for converging in a second direction orthogonal to the first direction toward the center of the slit and discharging a recording liquid from the slit toward the recording medium;
Cleaning means for cleaning foreign matter adhering to the vicinity of the slit by sliding a cleaning member on the upper surface of the container; and
The hole formed in the bottom of the storage container is formed at a position facing one end of the slit formed in the upper surface of the storage container,
The second position where the tank is lowered by the elevating means is that the recording liquid filled between the upper surface of the sound wave converging means and the upper surface of the container is between the holes through one end of the slit. Is set to a height that is separated from the recording liquid stored in the tank by the air flowing into the tank,
The cleaning means cleans the upper surface by sliding the cleaning member against the upper surface of the storage container in a state where the tank is lowered to the second position by the elevating means and the recording liquid is divided. Recording head.

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