JP2009149041A - Cleaning apparatus for inkjet head, and inkjet recording apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cleaning apparatus for inkjet head which can efficiently transmit the oscillating power of a cleaning fluid by an ultrasonic wave to a wide area including all nozzles on the surface of a nozzle plate, can effectively remove even ink contamination having firmly adhered, can prevent the removed contamination from adhering again, and can prevent the flowing of the fluid into the inside of the head by avoiding an unnecessary contact between the head and the cleaning fluid. <P>SOLUTION: This cleaning apparatus for inkjet head is equipped with a cleaning tub 12 in which the cleaning fluid is stored, and an ultrasonic oscillator 17. The cleaning tub 12 has an opening section 16 which can surround all the nozzles of the nozzle plate by closely contacting the nozzle plate. In the ultrasonic oscillator 17, an oscillating plate 17a which is arranged in a manner to face with an interval in parallel with the nozzle plate surface which is closely joined to the opening section 16, is arranged in the cleaning tub 12. The cleaning fluid W is filled to the upper surface side and the lower surface side of the oscillating plate 17a in the cleaning tub 12. Then, the cleaning fluid on the upper surface side of the oscillating plate 17a and the cleaning fluid on the lower surface side and the upper surface side can be circulated to each other. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an inkjet head cleaning apparatus and an inkjet recording apparatus, and more particularly to an inkjet head cleaning apparatus and an inkjet recording apparatus that can effectively clean the surface of a nozzle plate with a cleaning liquid excited by ultrasonic waves.

  The ink jet recording apparatus is provided with a cleaning device for removing ink stains adhering to the nozzle plate surface as one of head maintenance. As such a cleaning device, a device that wipes the surface of a nozzle plate using a blade or the like, a device that closes a suction cap on the nozzle plate, and forcibly sucks ink from the nozzle are generally known. However, these general cleaning devices have a problem that the ink strongly adhered to the nozzle plate surface cannot be sufficiently cleaned. In recent years, due to the demand for finer and higher-definition recording, the nozzle diameter has been further reduced, and now has a nozzle diameter of several μmφ.

  For this reason, conventionally, a method for cleaning the nozzle plate surface using a cleaning liquid excited by ultrasonic waves has been proposed as a method for cleaning even ink that has little damage to the nozzle and strongly adheres to the nozzle plate surface. Yes.

  Patent Document 1 discloses a method of performing cleaning by jetting a cleaning liquid excited by ultrasonic waves from a nozzle tip of a cleaning device toward a nozzle plate surface.

  Patent Document 2 discloses a method of immersing the head in a cleaning tank and passing the cleaning liquid through the head while applying ultrasonic waves in order to remove foreign matters inside the head at the manufacturing stage.

Furthermore, in Patent Document 3, an ultrasonic vibrator is attached to the outer bottom surface of the cap that closely contacts the nozzle surface of the nozzle plate, and the cleaning liquid in the cap is excited by the driving of the ultrasonic vibrator to clean the nozzle plate and the nozzle. A method is disclosed.
JP 2005-28758 A Japanese Patent Laid-Open No. 9-254397 JP 2006-347000 A

  In the method described in Patent Document 1, since the cleaning liquid excited by ultrasonic waves from the nozzle tip of the cleaning apparatus is jetted toward the nozzle plate surface, the cleaning liquid can only act locally on the nozzle plate surface. This is because the cleaning area is reduced as a result of reducing the cross-sectional area of the jet flow and providing vibration power efficiently. Therefore, there is a problem that cleaning is not possible over a large area of the nozzle plate surface. In addition, after the excited cleaning liquid collides with the surface of the nozzle plate, it scatters to the surroundings and contaminates the periphery of the head.

  Further, in the method described in Patent Document 2, since the head is immersed in the cleaning liquid, it is not possible to clean the nozzle plate surface of the head in a use state in which the inside is filled with ink. In this method, since the cleaning liquid comes into contact with a portion where the cleaning liquid is not desired to be touched, the cleaning liquid may inadvertently enter the inside.

  In the method described in Patent Document 3, since the cleaning liquid in the cap is brought into close contact with the nozzle surface and cleaned by an ultrasonic vibrator, the entire nozzle surface closely contacted with the cap can be cleaned. Is considered to be preferable as a method for cleaning the nozzle plate.

  However, since the ultrasonic transducer is attached to the outer bottom surface of the cap, the nozzle plate to be cleaned and the ultrasonic transducer must be separated by a distance of the depth of the cap + the thickness of the bottom surface of the cap. There is a problem that the vibration power of the ultrasonic vibrator cannot be efficiently applied to the nozzle surface via the cleaning liquid, and the stains strongly adhered to the nozzle surface cannot be effectively removed.

  To reduce the separation distance between the nozzle plate and the ultrasonic transducer, the cap must be shallow and the bottom surface must be thin. In this case, the volume of the cleaning liquid that can be stored in the cap is reduced because the cap volume is reduced. There is a problem that becomes less. When the amount of cleaning liquid in the cap decreases, the concentration of dirt in the cleaning liquid removed from the nozzle plate during cleaning increases, and dirt accumulates in the cap, leading to a reduction in the efficiency of the vibration power of the ultrasonic vibrator. This causes a problem that the dirt inside adheres again to the nozzle surface.

  Therefore, the present invention efficiently transmits the vibration power of the cleaning liquid excited by the ultrasonic wave to a wide area including all nozzles on the surface of the nozzle plate of the ink jet head in a use state in which the inside is filled with ink. The ink stain can be effectively removed even with strongly adhered ink stains, and the removed stains will not be reattached, and unnecessary contact between the head and the cleaning liquid is avoided, and only on the nozzle plate surface. It is an object of the present invention to provide an inkjet head cleaning device that can prevent the cleaning liquid from entering the head by contacting the liquid.

  In addition, another object of the present invention is to efficiently use the vibration power of the cleaning liquid excited by ultrasonic waves over a wide area including all nozzles on the surface of the nozzle plate of the ink jet head in a state where the inside is filled with ink. Even if ink stains that adhere strongly and can be effectively removed can be removed effectively, the removed stains will not be reattached, and unnecessary contact between the head and cleaning liquid is avoided, and only the surface of the nozzle plate It is an object of the present invention to provide an ink jet recording apparatus having a cleaning device capable of preventing the cleaning liquid from entering the head by bringing the liquid into contact with the head.

  Other problems of the present invention will become apparent from the following description.

  The above problems are solved by the following inventions.

  The invention according to claim 1 includes a cleaning tank in which a cleaning liquid is stored, and an ultrasonic vibrator, and the cleaning tank is formed on the nozzle plate by being in close contact with the nozzle plate of the inkjet head. The ultrasonic transducer has an opening that can surround all the nozzles, and the ultrasonic transducer is arranged so as to face the nozzle plate surface in close contact with the opening so as to face each other in parallel. A plate is disposed in the cleaning tank, and the cleaning liquid is filled in the upper surface side and the lower surface side of the vibration plate in the cleaning tank, and the cleaning liquid on the upper surface side of the vibration plate and the cleaning liquid on the lower surface side are An ink jet head cleaning apparatus characterized in that it can be distributed to each other.

  The invention according to claim 2 is the inkjet head cleaning device according to claim 1, wherein the diaphragm has an area equivalent to an opening area of the opening of the cleaning tank.

  In the invention according to claim 3, the cleaning tank has a box shape whose upper surface is larger than the opening, and the diaphragm is disposed below the lower end of the opening in the cleaning tank, 3. An ink jet head cleaning apparatus according to claim 1, wherein a gap through which the cleaning liquid can flow is formed between the lower end of the opening and the upper surface of the diaphragm.

  According to a fourth aspect of the present invention, there is provided a close contact portion that is in close contact with the surface of the nozzle plate at the periphery of the upper end of the opening portion, and a lead-out groove for allowing the cleaning liquid in the cleaning tank to flow out to a part of the close contact portion. And a cleaning liquid supply means for supplying the cleaning liquid into the cleaning tank so that the cleaning liquid in the cleaning tank flows out of the lead-out groove during cleaning. Or a cleaning device for an inkjet head according to 3.

  The invention according to claim 5 is the inkjet head cleaning device according to any one of claims 1 to 4, wherein the ultrasonic transducer is formed by attaching the diaphragm to the tip of a Langevin transducer. It is.

  The invention according to claim 6 has an ink jet head having a nozzle plate on which a large number of nozzles are formed, and performs recording by discharging ink from the nozzles, and the ink jet head according to any one of claims 1 to 5. And a moving means for relatively moving the inkjet head and a cleaning tank of the inkjet head cleaning apparatus to bring the nozzle plate into close contact with the opening of the cleaning tank. Inkjet recording apparatus.

  According to the present invention, it is possible to efficiently transmit the vibration power of the cleaning liquid excited by ultrasonic waves over a large area of the nozzle plate surface of the inkjet head, and effectively remove even strongly adhered ink stains. In addition, the removed dirt does not reattach, and unnecessary contact between the head and the cleaning liquid is avoided, and only the surface of the nozzle plate is in contact with the liquid so that the cleaning liquid enters the head. It is possible to provide a cleaning device for an inkjet head that can be prevented.

  In addition, according to the present invention, the vibration power of the cleaning liquid excited by the ultrasonic wave can be efficiently transmitted to a large area of the nozzle plate surface of the inkjet head, and even the strongly adhered ink stains can be effectively removed. In addition, the removed dirt does not reattach, and unnecessary contact between the head and the cleaning liquid is avoided, and only the surface of the nozzle plate is contacted to prevent the cleaning liquid from entering the head. An ink jet recording apparatus having a cleaning device capable of performing the above can be provided.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a perspective view showing an example of an inkjet head cleaning apparatus according to the present invention, and FIG. 2 is a longitudinal sectional view thereof.

  The cleaning apparatus 10 includes a cleaning tank 12 that is also box-shaped and has a bottom area smaller than that of the base 11, on the top of the box-shaped base 11. In the cleaning tank 12, the cleaning liquid W in the cleaning liquid tank 13 is supplied from the cleaning liquid supply hole 12 a through the cleaning liquid supply pipe 15 a by the operation of the cleaning liquid supply pump 14 and stored. In addition, the cleaning liquid W in the cleaning tank 12 is discharged from the cleaning liquid discharge hole 15b provided on the bottom surface of the cleaning tank 12 to the outside of the cleaning apparatus 10 through the cleaning liquid discharge pipe 15b. The cleaning liquid discharge pipe 15b is provided with an open / close valve (not shown) so as to be opened when the cleaning liquid W is discharged.

  This cleaning liquid W is preferably made of the same material as the solvent in the ink to be used, because it has good compatibility with the ink stains adhering to the nozzle plate and can effectively remove the ink stains. In addition, in an ink jet head that uses ink containing Ag particles, when adhesion of Ag particles in the ink to the nozzle plate surface becomes a problem, it is also preferable to use a sodium thiosulfate solution that functions as an Ag dissolving solution.

  An opening 16 is formed in the center of the upper surface of the cleaning tank 12. As will be described later, the opening 16 is for contacting and closely contacting the surface of the nozzle plate when the inkjet head is cleaned. As shown in FIG. The nozzle plate 21 is formed in a rectangular shape having an opening area that is smaller than the surface of the nozzle 21 and has an opening area that can surround all the many nozzles 21 a arranged in the nozzle plate 21. The upper surface of the cleaning tank 12 has a larger area than the opening 16. For this reason, the internal space of the cleaning tank 12 having a box shape is larger in the lateral direction than the size of the opening 16.

  The peripheral edge of the upper end of the opening 16 protrudes from the upper surface of the cleaning tank 12 and is a wall-shaped contact portion 16a for closely contacting the surface of the nozzle plate in a liquid-tight manner. The protruding height from the upper surface of the cleaning tank 12 can be set to 2 to 3 mm, for example. The material of the contact portion 16a is not particularly limited as long as the surface of the nozzle plate can be adhered in a liquid-tight manner, but it is an elastic material in that the damage to the nozzle plate is small and can be easily liquid-tight. For example, rubber can be used.

  Inside the cleaning tank 12, an ultrasonic transducer 17 that is activated by energization to generate ultrasonic waves is disposed. The ultrasonic transducer 17 is attached so as to vertically penetrate the bottom surface of the cleaning tank 12 (the top surface of the base 11), and the tip side thereof extends so as to be close to the opening 16, and a flat plate is provided at the tip. A vibrating plate 17 a is disposed below the lower end 16 ′ of the opening 16 in the cleaning tank 12 with a slight distance. Therefore, when the cleaning tank 12 is filled with the cleaning liquid W, the vibration plate 17a is completely submerged in the cleaning liquid W and faces parallel to the surface of the nozzle plate that is in close contact with the upper end of the contact portion 16a. .

  As the ultrasonic transducer 17, a Langevin type transducer can be preferably used. The Langevin type vibrator vibrates the horn 17b at the tip by energizing a piezoelectric element provided in itself, and vibrates the flat plate-like diaphragm 17a fixed to the tip integrally to generate ultrasonic waves. generate. Since the diaphragm 17a is fixed to the tip of the horn 17b extending so as to be close to the opening 16 from the bottom surface of the cleaning tank 12, it can be disposed in the cleaning tank 12 close to the opening 16. The ultrasonic vibration power generated by the vibration of the vibration plate 17a can be efficiently applied to the nozzle plate.

  The surface of the diaphragm 17a has an area equivalent to the opening area of the opening 16, and the surface shape allows the cleaning liquid W excited by ultrasonic waves to efficiently act on the entire surface of the nozzle plate. In order to be able to do so, it is formed in the same rectangular shape as the opening shape of the opening 16.

  As shown in FIG. 4, the vibration power generated by the diaphragm 17a is attenuated as the separation distance L1 between the surface of the diaphragm 17a and the upper end of the contact portion 16a that is a contact surface with the nozzle plate increases. Therefore, from the viewpoint of allowing the vibration power of the vibration plate 17a to efficiently act on the cleaning liquid W in the meantime and effectively bringing the excited cleaning liquid W into contact with the surface of the nozzle plate, 1 to 5 mm. It is preferable that it is 1 to 3 mm.

  Further, even if the surface of the diaphragm 17a has the same size as the opening 16, the cleaning liquid W1 existing between the surface of the nozzle plate and the upper surface of the diaphragm 17a in the cleaning tank 12, and the lower surface of the diaphragm 17a The separation distance L2 between the upper surface of the diaphragm 17a and the lower end 16 ′ of the opening 16 in the cleaning tank 12 is set to 0.5 to 3 mm so that the liquid can flow between the cleaning liquid W2 existing in the cleaning tank 12a. Thus, it is preferable to provide the cleaning liquid channel gap 19.

  The surface of the base 11 is larger than the installation area of the cleaning tank 12, and a wall portion 11 a is erected on the upper surface so as to surround the periphery of the cleaning tank 12. The wall 11a functions as a weir to prevent the cleaning liquid W overflowing from the opening 16 from flowing out of the base 11, and a cleaning liquid drain port 11b is opened at any one or a plurality of locations inside the wall 11a. Then, the cleaning liquid discharge pipe 18 drains the cleaning apparatus 10 to the outside. The wall portion 11a is not limited to be formed standing on the surface of the base 11, but may be formed by a stepped portion.

  The cleaning device 10 is installed outside the recording work area in the movable area of the inkjet head in the inkjet recording apparatus. FIG. 5 shows a schematic configuration diagram of an ink jet recording apparatus having the cleaning device 10. Here, the ink jet head 20 is driven and controlled by a control unit 30, an X axis moving motor 31, a Y axis moving motor 32, and a Z axis. It is provided so as to be movable in the X-axis, Y-axis, and Z-axis directions by driving the moving motor 33. The control unit 30 controls the supply of the cleaning liquid into the cleaning tank 12 of the cleaning apparatus 10 by controlling the driving of the cleaning liquid supply pump 14, and includes an ultrasonic driving unit 34 for operating the ultrasonic vibrator 17. Drive.

  Next, a method of cleaning the ink jet head by the cleaning apparatus 10 will be described with reference to the flowchart of FIG.

  First, the control unit 30 appropriately drives the X-axis movement motor 31, the Y-axis movement motor 32, and the Z-axis movement motor 33 to move the inkjet head 20 to above the opening 16 of the cleaning tank 12 in the cleaning device 10 ( S1).

  Next, the control unit 30 drives the cleaning liquid supply pump 14 to supply the cleaning liquid W from the cleaning liquid tank 13 into the cleaning tank 12 (S2).

  As shown in FIG. 7, the amount of the cleaning liquid supplied at this time is such that the liquid surface position A of the cleaning liquid W is higher than the upper end of the opening 16, that is, the upper end position B of the contact portion 16a, due to the surface tension of the cleaning liquid W. To supply.

  The protrusion height of the liquid surface position A of the cleaning liquid W maintained so as to be high by this surface tension with respect to the upper end position B of the contact portion 16a is preferably 0.1 to 3 mm, more preferably 0.5 to 1 mm. Is to do so.

  In order to increase the liquid surface position A of the cleaning liquid W by the surface tension in this way, since the cleaning liquid W has a small surface energy, a material having a large surface energy is selected on the solid side to be contacted, that is, the contact portion 16a. It is preferable to increase the liquid level by increasing the contact angle. Specifically, it is preferable to use a material having high liquid repellency and high elasticity, such as fluorine rubber, silicon rubber, and chloroprene rubber, for the contact portion 16a.

When the cleaning tank 12 is filled with the cleaning liquid W, as shown in FIG. 7, the rising angle θ of the liquid level formed by the cleaning liquid W is ₁ at the upper edge 16 a ₁ of the close contact portion 16 a due to surface tension. It is preferable that the angle is 30 °.

  In order to supply the cleaning liquid W so that the liquid surface position A is higher than the upper end position B of the contact portion 16a due to surface tension in this way, although not shown, for example, the liquid surface position A higher than the upper end of the contact portion 16a is set. A liquid level detecting means having a light emitting element and a light receiving element arranged so as to sandwich the contact portion 16a is provided at a detectable position, and the control unit 30 sets the liquid level position A of the cleaning liquid W to a predetermined position. A method of optically detecting that the cleaning liquid supply pump 14 has been stopped by optically detecting that it has come, and a flow rate detecting means such as a flow rate sensor is provided in the supply path of the cleaning liquid W. Examples include a method in which the control unit 30 controls the operation stop of the cleaning liquid supply pump 14 so that the predetermined amount is supplied so as to be higher than the upper end position B of the close contact portion 16a.

  After supplying the cleaning liquid W into the cleaning tank 12 and stopping the cleaning liquid supply pump 14 in this way, the control unit 30 lowers the inkjet head 20 and opens the nozzle plate 21 as shown in FIG. The close contact portion 16a is brought into contact with the 16 close contact portions, and the opening portion 16 is sealed by the surface of the nozzle plate 21 (S3). Here, since the liquid level of the cleaning liquid W is higher than the upper end of the contact portion 16a due to surface tension, the nozzle plate 21 first contacts the cleaning liquid W and then contacts the upper end of the contact portion 16a. Therefore, air (bubbles) does not intervene on the surface with the nozzle plate 21, and no air (bubbles) pool is formed in the opening 16.

  Thereafter, the control unit 30 controls the ultrasonic drive unit 34 to operate the ultrasonic transducer 17. As a result, the vibration plate 17a vibrates to generate ultrasonic waves and excites the cleaning liquid W on the surface. The drive frequency of the ultrasonic transducer 17 is preferably 20 to 50 kHz. Thereby, the surface of the nozzle plate 21 surrounded by the opening 16 is cleaned by the excited cleaning liquid W (S4).

  The dirt removed from the surface of the nozzle plate 21 at the time of cleaning is mixed into the cleaning liquid W1 on the upper surface side of the vibration plate 17a, but the contamination with the clean cleaning liquid W2 on the lower surface side of the vibration plate 17a is interposed via the cleaning liquid channel gap 19. Since the liquid can be distributed, the removed dirt can escape to the lower surface side of the vibration plate 17a in the washing tank 12 through the washing liquid channel gap 19, and the dirt is removed by continuing washing with the dirty washing liquid W. There is no risk of reattaching to the surface of the nozzle plate 21.

  When a predetermined cleaning time has elapsed, the control unit 30 stops the operation of the ultrasonic transducer 17, raises the inkjet head 20 to separate from the contact portion 16a, and ends the cleaning operation (S5).

  According to the present invention, since the vibration plate 17a having the same surface area as the opening 16 is immersed in the cleaning liquid W and disposed close to the surface of the nozzle plate 21, the vibration plate 17a to be acted on the cleaning liquid W is provided. Loss of vibration power is extremely small. For this reason, it is possible to transmit vibration power directly to the cleaning liquid W interposed in the narrow space between the surface of the nozzle plate 21 and the surface of the vibration plate 17a to efficiently excite the excited cleaning liquid W. This cleaning effect can be effectively applied to the surface of the nozzle plate 21. Therefore, the vibration power of the cleaning liquid W excited by the ultrasonic wave can be efficiently transmitted to a wide area including all the nozzles 21a on the surface of the nozzle plate 21 of the ink jet head in a use state in which the inside is filled with ink. Ink stains strongly adhering to the surface of the nozzle plate 21 can be effectively removed.

  Further, since the inkjet head and the cleaning liquid W need only be brought into contact with the surface including all the nozzles 21a of the nozzle plate 21, the cleaning liquid W does not inadvertently flow into the head.

  Further, since the removed dirt can escape to the lower surface side of the vibration plate 17a in the cleaning tank 12 through the cleaning liquid channel gap 19, there is no possibility that the dirt will reattach to the surface of the nozzle plate 21.

  FIG. 9 is a perspective view showing another aspect of the inkjet head cleaning apparatus according to the present invention. The parts denoted by the same reference numerals as those in FIG. 1 indicate the parts having the same configuration, and detailed description thereof will be omitted.

  In the cleaning device 100, the upper end of the close contact portion 16a formed in the opening portion 16 is partially cut out, and a lead-out groove 16b serving as a flow path for the cleaning liquid overflowing from the opening portion 16 is appropriately formed in the close contact portion 16a. Numbers are formed. In addition, the cleaning liquid overflowing from the opening 16 is guided to the inside of the wall 11a on the upper surface of the base 11 from the outlet groove 16b so as to be continuous with the outlet groove 16b from the upper surface to the side surface. A guide groove 12c is formed.

  Next, a method of cleaning the ink jet head by the cleaning apparatus 100 will be described with reference to the flowchart of FIG.

  First, the control unit 30 appropriately drives the X-axis movement motor 31, the Y-axis movement motor 32, and the Z-axis movement motor 33 to move the inkjet head 20 to above the opening 16 of the cleaning tank 12 in the cleaning apparatus 100 ( S11).

  Next, as shown in FIG. 11, the control unit 30 lowers the inkjet head 20 to bring the nozzle plate 21 into contact with the contact portion 16 a of the opening portion 16 (S12). Since the lead-out groove 16b is formed in the close contact portion 16a, when the nozzle plate 21 is brought into close contact, the inside of the cleaning tank 12 and the outside of the cleaning device 100 communicate with each other only through the lead-out groove 16b. At this time, the cleaning tank 12 is empty or is not filled with the cleaning solution to the extent that it overflows from the opening 16.

  Thereafter, the control unit 30 drives the cleaning liquid supply pump 14 to supply the cleaning liquid W from the cleaning liquid tank 13 into the cleaning tank 12 and controls the ultrasonic driving unit 34 to control the ultrasonic transducer 17 in the same manner as described above. Operate. As a result, the ultrasonic vibrator 17a vibrates to generate ultrasonic waves, and the surrounding cleaning liquid W is excited. At the same time, the surface of the nozzle plate 21 surrounded by the opening 16 is cleaned by the excited cleaning liquid W. (S13).

  At the time of this cleaning, as shown in FIG. 12, the control unit 30 continues to supply the cleaning liquid W so as to continuously overflow from the outlet groove 16b of the contact portion 16a. The cleaning liquid W is supplied to the upper surface side of the vibration plate 17 a through the cleaning liquid channel gap 19. The supply amount of the cleaning liquid W only needs to flow out from the outlet groove 16b. By doing so, the air (bubble) pool interposed between the surface of the nozzle plate 21 and the cleaning liquid W when the nozzle plate 21 is in close contact is pushed to the nozzle plate 21 side with the supply of the cleaning liquid W, and the lead-out groove 16b. Is discharged to the outside. Therefore, the cleaning liquid W excited by ultrasonic waves can efficiently transmit the vibration power to the surface of the nozzle plate 21 without loss due to air (bubbles), and can effectively exert a cleaning action.

  Further, since the opening portion 16 is in close contact with the surface of the nozzle plate 21 by the close contact portion 16a, the cleaning liquid W in the opening portion 16 excited by ultrasonic waves is concentrated on the surface of the nozzle plate 21 in the opening portion 16. Thus, a cleaning action can be exerted. For this reason, the ultrasonic vibration power is applied to all the nozzles of the nozzle plate 21 of the ink jet head in a use state in which the inside is filled with ink, so that all nozzles on the surface of the nozzle plate 21 in the opening 16 have a wide area. Can be provided efficiently.

  Of course, also in this aspect, since the diaphragm 17a having the same surface area as the opening 16 is immersed in the cleaning liquid W and disposed close to the surface of the nozzle plate 21, the vibration plate 17a to be acted on the cleaning liquid W is provided. The loss of vibration power is extremely small, and even ink stains strongly adhered to the surface of the nozzle plate 21 can be effectively removed.

  Further, since the inkjet head and the cleaning liquid W need only be brought into contact with the surface including all the nozzles 21a of the nozzle plate 21, the cleaning liquid W will not inadvertently enter the head.

  Further, the new cleaning liquid W continues to be supplied to the upper surface side of the vibration plate 17a through the cleaning liquid channel gap 19, and the cleaning liquid W including the removed dirt is discharged to the outside from the outlet groove 16b of the contact portion 16a. There is no possibility of reattaching to the surface of the nozzle plate 21.

  When the predetermined cleaning time has elapsed, the control unit 30 stops the operation of the cleaning liquid supply pump 14 and the ultrasonic vibrator 17 (S14), and then raises the inkjet head 20 to separate it from the contact portion 16a. The cleaning operation is finished (S15).

  In the above description, the ink jet head 20 is moved down and brought into close contact with the opening 16 on the upper surface of the cleaning tank 12 of the positionless cleaning apparatus 10, 100, but the ink jet head 20 and the cleaning tank 12 of the cleaning apparatus 10, 100 are used. As long as it is relative, the movement may be relative. Accordingly, the entire cleaning device 10, 100 or only the cleaning tank 12 may be raised with respect to the stopped inkjet head 20, or both the inkjet head 20, the entire cleaning device 10, 100, or the cleaning tank 12 may be mutually connected. It may be moved.

The perspective view which shows an example of the washing | cleaning apparatus of the inkjet head which concerns on this invention. 1 is a longitudinal sectional view of the cleaning apparatus shown in FIG. Plan view of inkjet head showing size of opening The figure which shows arrangement | positioning of an opening part and an ultrasonic transducer | vibrator 1 is a schematic configuration diagram of an inkjet recording apparatus having an inkjet head cleaning apparatus according to the present invention. Flow chart explaining the cleaning method of the inkjet head The figure which shows the state which maintained the liquid level position of the washing | cleaning liquid higher than the upper end of the opening part by surface tension The figure which shows the state which stuck the nozzle plate to the upper end of an opening part The perspective view which shows the other aspect of the washing | cleaning apparatus of the inkjet head which concerns on this invention. Flow chart for explaining a method of cleaning an inkjet head according to another embodiment The figure which shows the state which stuck the nozzle plate to the upper end of the opening part which has a derivation | leading-out groove | channel. The figure which shows a mode that it continues supplying cleaning liquid and is cleaned

Explanation of symbols

DESCRIPTION OF SYMBOLS 10,100: Cleaning apparatus 11: Base 11a: Wall part 11b: Cleaning liquid drain 12: Cleaning tank 12a: Cleaning liquid supply hole 12b: Cleaning liquid discharge hole 12c: Channel groove 13: Cleaning liquid tank 14: Cleaning liquid supply pump 15a: Cleaning liquid Supply pipe 15b: Cleaning liquid discharge pipe 16: Opening 16 ': Lower end of opening 16a: Close contact 16a ₁ : Upper edge 16b: Derivation groove 17: Ultrasonic vibrator 17a: Ultrasonic vibrator 18: Cleaning liquid discharge pipe 19 : Cleaning liquid channel gap 20: Inkjet head 21: Nozzle plate 21 a: Nozzle 30: Control unit 31: X-axis movement motor 32: Y-axis movement motor 33: Z-axis movement motor 34: Ultrasonic drive unit W: Cleaning liquid W1: Vibration Cleaning liquid on the upper surface side of the plate W2: Cleaning liquid on the lower surface side of the diaphragm

Claims (6)

A cleaning tank in which cleaning liquid is stored and an ultrasonic vibrator are provided.
The cleaning tank has an opening that can surround all nozzles formed in the nozzle plate by closely contacting the nozzle plate of the inkjet head,
The ultrasonic transducer has a vibration plate disposed in the cleaning tank so as to face in parallel with a gap between the nozzle plate surface and the surface close to the opening. An inkjet head cleaning apparatus, wherein the cleaning liquid is filled in an upper surface side and a lower surface side of the diaphragm in a tank, and the cleaning liquid on the upper surface side of the diaphragm and the cleaning liquid on the lower surface side can circulate with each other. .   2. The inkjet head cleaning apparatus according to claim 1, wherein the diaphragm has an area equivalent to an opening area of the opening of the cleaning tank.   The cleaning tank has a box shape whose upper surface is larger than the opening, and the diaphragm is disposed below the lower end of the opening in the cleaning tank, and the lower end of the opening and the vibration 3. An ink jet head cleaning apparatus according to claim 1, wherein a gap through which the cleaning liquid can flow is formed between the upper surface of the plate and the upper surface of the plate. A close contact portion that is in close contact with the surface of the nozzle plate is erected on an upper end periphery of the opening portion, and a lead-out groove for allowing the cleaning liquid in the cleaning tank to flow out is formed in a part of the close contact portion,
4. The inkjet head according to claim 1, further comprising cleaning liquid supply means for supplying the cleaning liquid into the cleaning tank so that the cleaning liquid in the cleaning tank flows out of the lead-out groove during cleaning. Cleaning device.   The inkjet head cleaning apparatus according to any one of claims 1 to 4, wherein the ultrasonic transducer is formed by attaching the diaphragm to a tip of a Langevin type transducer. An inkjet head having a nozzle plate on which a large number of nozzles are formed, and performing recording by discharging ink from the nozzles;
An inkjet head cleaning device according to any one of claims 1 to 5,
An ink jet recording apparatus comprising: a moving unit that relatively moves the ink jet head and a cleaning tank of the ink jet head cleaning device to bring the nozzle plate into close contact with the opening of the cleaning tank.

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