JP2006231808A - Nozzle moisture retaining mechanism for ink-jet head, and ink-jet recording device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a moisture retaining mechanism for an ink-jet head, which improves the hermeticity of the interior of a nozzle cap, and completely blocks the interior of the nozzle cap from the outside, to thereby prevent clogging of a nozzle caused by drying of ink. <P>SOLUTION: According to the operation of the nozzle moisture retaining mechanism, after suction operation, a nozzle cap unit 25 is elevated by a pressure P2 while a suction valve 19 is kept opened, and the entire area of a seal lip is intimately stuck to a nozzle plate 11, followed by closing the suction valve 19. Thus an ink discharge communication pipe 17 is filled with the ink, and no gap is formed between the seal lip 15 and the nozzle plate 11, which enables complete blocking of the interior of the nozzle cap, to thereby prevent drying of the nozzle. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a nozzle moisturizing mechanism for an ink jet head that includes a nozzle cap that protects a nozzle that ejects ink and a nozzle plate from clogging and ink drying.

  2. Description of the Related Art Conventionally, an ink jet recording apparatus that records characters and images on a recording medium using an ink jet head having a plurality of nozzles that eject ink is known. In such an ink jet recording apparatus, the nozzle of the ink jet head is provided in the head holder so as to face the recording medium, and this head holder is mounted on the carriage so as to be scanned in a direction orthogonal to the transport direction of the recording medium. It has become.

  In such an ink jet recording apparatus, the ink jet head is stored in the home position when the apparatus is in a resting state. The nozzle and nozzle plate of the stored inkjet head have a problem that the nozzle becomes clogged due to thickened or dried ink or adhered foreign matter over time, and normal ink droplets cannot be ejected. In order to prevent a decrease in ejection reliability due to clogging or the like, a protective structure is employed in which moisture is retained by an airtight space formed by covering the head nozzle surface from the outside to prevent ink drying.

  FIG. 7 is a cross-sectional view showing a conventional example of a structure in which the target nozzle cap 4 is pressed against the inkjet head nozzle portion. In this case, the outer periphery of the nozzle of the nozzle plate 2 is covered from the outside with a nozzle cap 4 formed of an elastic member such as rubber, and the seal lip 5 is brought into close contact with each other, thereby forming a sealed space 7 inside and blocking outside air to prevent drying. is doing.

  The nozzle cap 4 has a maintenance function for sucking thick ink and bubbles from the nozzle 1 and supplying normal ink as well as for preventing the nozzle portion from drying. A communication tube 6 for discharging ink from the nozzle cap 4 is provided, and the abnormal ink 9 and air bubbles that are thickened in the inkjet head are discharged by suction.

  Further, the air remaining in the sealed space 7 in the cap is agitated with the ink sucked out of the nozzle by the suction operation, becomes a fine bubble, and flows back into the nozzle and stagnates. These bubbles cause a damper effect and hinder normal ink ejection. Therefore, an absorber 8 is provided in the nozzle cap 4 so as to adsorb fine bubbles.

  Ink adhering to the nozzle plate 2 by suction is wiped off by a wiper installed in the vicinity of the nozzle cap 4 after the suction operation. At this time, foreign matter adhering to the nozzle plate 2 is also removed at the same time.

In order to print high-quality characters and images while maintaining the ejection performance of the head, it is necessary that an appropriate meniscus is always formed on the ink surface at the tip of the nozzle. Needless to say, the nozzle 1 and the nozzle plate 2 have no damage such as scratches or foreign matter attached thereto, but the ink in the nozzle, which is less ejected by the image data during the scanning of the inkjet head, increases in viscosity. End up. For this purpose, the inkjet head periodically returns to the home position, controls abnormal spout, suction or pressurization to discharge abnormal ink, and supplies normal ink to form an appropriate meniscus.
Japanese Patent Laid-Open Nos. 6-210861 and 10-146986

  In the conventional nozzle moisturizing mechanism of the ink jet head described above, even if the outside air is shut off, the air remaining in the cap causes the ink to thicken and dry, and the nozzle clogging and ink drying are completely eliminated. There is a problem that cannot be prevented.

  Particularly in recent years, many solvent-based inks have been used, and the drying speed of ink has been remarkably increased. For this reason, there is a problem that the ink is dried and fixed on the nozzle plate in contact with the ink adhering to the outer periphery of the seal lip, peels off at the time of wiping, and rubs against the wiper to damage the nozzle plate and the nozzle.

  In addition, an absorber is provided in the conventional nozzle cap, but when the abnormal ink is discharged from the nozzle cap, the absorber traps foreign matter and deposits it in the nozzle cap and adheres to the nozzle surface. There is also a problem that the ink enters the negative pressure nozzle.

  SUMMARY OF THE INVENTION In view of such circumstances, the present invention provides an ink-jet head moisturizing mechanism that can easily prevent nozzle clogging and ink drying by improving airtightness and maintaining moisture retention of the nozzle and nozzle plate. It is the purpose.

A first problem-solving means of the present invention that solves the above-described object is a moisture retention mechanism of an inkjet head that forms a blocking space from outside air by contacting the nozzle surface of the inkjet head,
A nozzle cap provided with an outer peripheral portion in close contact with the head cap at the tip of the ink jet head including the nozzle surface of the ink jet head at the first position, and a bottom surface portion in close contact with the nozzle surface at the second position; An ink-jet head moisturizing mechanism is provided.

  According to a second aspect of the present invention, there is provided a moisture retention mechanism for an ink jet head, wherein the nozzle cap is elastically deformable.

  According to a third aspect of the present invention, there is provided an inkjet head that ejects ink onto a recording medium, a carriage that conveys the inkjet head, a recording medium conveyance mechanism that conveys the recording medium, and the inkjet An ink-jet recording apparatus having an ink-jet moisturizing mechanism that abuts against the nozzle surface of the head and forms a blocking space from outside air, the ink-jet recording having the ink-jet head moisturizing mechanism of the first or second solving means Device.

  According to a fourth aspect of the present invention, there is provided an ink jet recording apparatus having a third means for solving, wherein the outer peripheral edge of the head cap has a tapered portion formed in a tapered shape.

  A fifth problem solving means of the present invention is the ink jet recording apparatus having the fourth solving means, wherein the tapered portion is subjected to water repellent treatment.

  The sixth problem-solving means of the present invention is characterized in that a frame body spring that reinforces and supports close contact with the nozzle surface is coupled outside the nozzle cap so as to cover the nozzle cap. 2 is a moisturizing mechanism of an ink jet head having two solving means.

  According to a seventh aspect of the present invention, there is provided a moisturizing mechanism for an ink-jet head having sixth means for solving, characterized in that a rigid pressure base is provided in the vicinity of the back surface of the frame spring.

  Further, an eighth problem-solving means of the present invention is characterized in that the frame body spring is elastically deformed by raising the pressing base, the nozzle cap is elastically deformed, and the nozzle surface and the tapered portion are in close contact with each other. In the moisture retention mechanism of the inkjet head having the seventh solving means.

  A ninth problem-solving means of the present invention is an ink-jet head moisturizing mechanism having eighth solving means characterized in that the pressing pressure height of the pressing base can be controlled in two stages.

  The effect | action by the said problem-solving means is as follows. The nozzle surface can be sealed to prevent foreign matter from entering from the outside. In addition, the ink can be prevented from drying by blocking from the atmosphere.

  Further, since the taper portion is closely attached so that the inner surface of the seal lip is wrapped, a high position system is not required. Further, it is possible to prevent leakage due to distortion deformation such as the fall of the seal lip.

  Further, the water-repellent treatment can smoothly insert and remove the nozzle cap and the seal lip. Furthermore, foreign matter and ink mist can be made difficult to adhere due to a synergistic effect with the taper. Moreover, the seal lip can be stabilized and the adhesion can be enhanced by a frame spring that reinforces and supports the nozzle cap.

In addition, the frame body spring can be uniformly pushed up by the rigid pressure base. Also, since the nozzle cap can be pressed by the pressure base, the nozzle cap sticks flatly to the nozzle surface. It is possible to completely block the outside air by closely adhering to the air.

  Further, the two purposes of the head maintenance and recovery by suction and the nozzle protection that prevents the ink from drying by blocking the atmosphere can be executed by a series of operations.

  As described above, the moisture retention mechanism of the inkjet head of the present invention can maintain the adhesion without pressing the seal lip of the nozzle cap against the nozzle plate, so that the dried ink does not adhere to the nozzle plate. In addition, by providing a taper on the head cap and increasing the contact surface with the seal lip, airtightness is improved and it can be completely blocked from outside air, and nozzle clogging due to ink drying can be easily prevented. .

  Hereinafter, the present invention will be described in detail based on embodiments of the present invention. Of course, it goes without saying that the present invention is not limited to this.

  FIG. 1 is an exploded perspective view of a nozzle moisturizing mechanism of an inkjet head, and FIG. 2 is a perspective view of the nozzle moisturizing mechanism. As shown in FIGS. 1 and 2, a frame body spring 14 is coupled to the seal lip 15, and a pressing base 16 is provided on the back surface of the frame body spring 14. Cuts are made in the four corners of the frame body spring 14 and are formed so as to be planar when a force is applied from below. In each part, a communication pipe 17 that discharges ink and a communication pipe 18 that opens and closes the atmosphere are joined to form a nozzle cap unit 25.

  The nozzle cap unit 25 has a function of moisturizing the nozzle 10 by discharging periodic thickening abnormal ink performed during scanning of the ink-jet head, and a function of protecting and moisturizing the entire nozzle plate 11 at rest. . FIG. 3 is a cross-sectional view when the ink jet head 51 returns to the home position, and FIG. 4 shows a state during ink suction and discharge operations. A taper portion 13 having a shape that fits and adheres to the inner surface of the seal lip 15 is provided on the outer peripheral flange portion of the head cap 12. Further, the taper portion 13 is subjected to water repellent treatment in order to enhance the detachability with the seal lip 15.

  In the suction operation, first, the air release valve 21 is closed, the nozzle cap unit 25 is raised by the pressure P1, and the seal lip 15 is fitted to the taper portion 13. Further, the nozzle cap unit 25 is raised and stopped at a predetermined gap L that is in close contact with the seal lip 15. Thereafter, the suction pump 20 is operated to discharge the abnormal ink 30 having increased viscosity from the ink discharge communication pipe 17. The rising stop height of the nozzle cap unit 25 is controlled by a proximity sensor (not shown). As is well known, after the appropriate amount of ink has been discharged, the suction valve 19 is closed, and then the atmosphere release valve 21 shown in FIGS. 1 and 2 is opened to leak.

  FIG. 5 is a cross-sectional view showing a moisturizing state of the nozzle moisturizing mechanism at rest. After the series of suction operations described above, the nozzle cap unit 25 is raised by pressing P2 while the suction valve 19 is opened, and the entire surface of the seal lip is brought into close contact with the nozzle plate 11, and then the suction valve 19 is closed. The ink discharge communication pipe 17 is filled with ink, and there is no gap between the seal lip 15 and the nozzle plate 11 and can be completely blocked from the outside air. Needless to say, when the ink jet recording apparatus is restarted, the nozzle cap unit 25 is lowered after the air release valve 21 is opened and leaked.

  In other words, in the first position where the nozzle cap unit performs the ink suction and discharge operations shown in FIG. 4, the outer peripheral portion 15a of the nozzle cap is in close contact with the head cap 12, and the nozzle moisturizing state at rest in FIG. Then, it stops at the second position, and the bottom surface portion 15 b of the nozzle cap is in close contact with the nozzle plate 11.

  Further, the nozzle moisturizing mechanism formed in this way is used in an ink jet recording apparatus, for example. An outline of an example of this use mode is shown in FIG.

  As shown in FIG. 6, the inkjet head 51 is mounted on a pair of guide rails 62 a and 62 b so as to be movable in the axial direction, and is provided on one end side of the guide rails 62 a and 62 b and connected to the carriage drive motor 63. It is conveyed via a timing belt 65 that is stretched over the pulley 64a that is provided and a pulley 64b that is provided on the other end side. A pair of transport rollers 66 and 67 are provided along guide rails 62a and 62b on both sides in the direction orthogonal to the transport direction of the inkjet head 51, respectively. These transport rollers 66 and 67 are for transporting the recording medium S below the ink jet head 51 in a direction perpendicular to the transport direction of the ink jet head 51.

  Below the inkjet head 51, the nozzle cap unit 25 of the present invention described above is provided as a nozzle moisturizing mechanism 70 of the inkjet head in a place where it does not come into contact with the recording medium S. Is moisturizing.

  With such an ink jet recording apparatus, characters and images can be recorded on the recording medium S by scanning the ink jet head 51 in a direction orthogonal to the feeding direction while feeding the recording medium S.

It is a disassembled perspective view of the nozzle moisture retention mechanism of the inkjet head which concerns on this invention. It is a perspective view of the nozzle moisturizing mechanism of the inkjet head according to the present invention. FIG. 2 is a cross-sectional view of a nozzle moisturizing mechanism of an ink-jet head according to the present invention and a cross-sectional view of the ink-jet head. FIG. 4 is a cross-sectional view of an ink suction state of a nozzle moisturizing mechanism of the inkjet head shown in FIG. 3. It is sectional drawing which shows the moisture retention state of the nozzle moisture retention mechanism of the inkjet head shown in FIG. 1 is a schematic perspective view of an ink jet recording apparatus according to the present invention. It is sectional drawing of the nozzle moisture retention mechanism of the inkjet head which concerns on a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Nozzle 11 Nozzle plate 12 Head cap 13 Tapered part 14 Frame body spring 15 Seal lip 16 Press base 19 Suction valve 21 Atmospheric release valve 25 Nozzle cap unit 51 Inkjet head

Claims (9)

A moisture retention mechanism for an inkjet head that forms a blocking space with outside air by contacting the nozzle surface of the inkjet head,
A nozzle cap provided with an outer peripheral portion in close contact with the head cap at the tip of the ink jet head including the nozzle surface of the ink jet head at the first position, and a bottom surface portion in close contact with the nozzle surface at the second position; Moisturizing mechanism for inkjet head The ink-jet head moisturizing mechanism according to claim 1, wherein the nozzle cap is elastically deformable. An inkjet head that discharges ink to a recording medium, a carriage that conveys the inkjet head, a recording medium conveyance mechanism that conveys the recording medium, and a blocking space from outside air that is in contact with the nozzle surface of the inkjet head An ink jet recording apparatus having an ink-jet moisturizing mechanism for forming an ink jet recording apparatus, comprising the ink-jet head moisturizing mechanism according to claim 1. 4. The ink jet recording apparatus according to claim 3, wherein the outer peripheral edge of the head cap has a tapered portion formed in a tapered shape.   5. The ink jet recording apparatus according to claim 4, wherein the taper portion is subjected to a water repellent treatment.   3. A moisture retention mechanism for an ink jet head according to claim 2, wherein a frame body spring that reinforces and supports close contact with the nozzle surface is coupled to the nozzle cap so as to cover the nozzle cap.   7. A moisture retention mechanism for an inkjet head according to claim 6, wherein a rigid pressing base is provided in the vicinity of the back surface of the frame spring.   8. The moisture retention mechanism for an ink jet head according to claim 7, wherein the frame body spring is elastically deformed by the rise of the pressing base, the nozzle cap is elastically deformed, and is brought into close contact with the nozzle surface and the tapered portion.   9. The moisture retention mechanism of an ink jet head according to claim 8, wherein the pressing pressure height of the pressing base can be controlled in two stages.

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