JP6475122B2 - inkjet printer - Google Patents

Description

  The present invention relates to an inkjet printer.

  Printers equipped with an ink jet recording head are widely known. Ink jet recording heads sometimes cause ejection defects due to clogging of nozzles with foreign matter or thickened ink. In order not to cause such a problem, the recording head periodically cleans the nozzle surface and the inside of the nozzle. For example, the nozzle surface is wiped with a wiper in order to remove foreign matter adhering to the nozzle surface of the recording head. In addition, the cap is closely attached to the nozzle surface and sealed to prevent the ink in the nozzle from thickening. In addition, nozzles are prevented from being clogged by discharging ink from the recording head to a tray that receives ink droplets and discharging the thickened ink. By performing such cleaning and moisturizing, ejection failure is prevented.

  However, when the nozzle surface is sealed with the cap, the evaporation of the volatile components of the ink is suppressed by the cap, but the meniscus of the ink of the nozzle may be broken. For example, after the cap is brought close to the nozzle surface and brought into contact with the nozzle surface, the cap is further moved in the nozzle surface direction so as to be tightly adhered to ensure a sealed state. The deformation of the tip of the cap reduces the volume of the sealed space. Therefore, the pressure in the cap increases by the amount that the volume is reduced. Conversely, when the cap is removed, the pressure is reduced by increasing the volume of the sealed space until the cap moves away from the nozzle surface, and at the moment of separation, the pressure inside the cap is equal to the pressure of the outside air. Change suddenly. Further, when the temperature changes in a sealed state, the pressure in the cap also changes.

  When such a change in pressure in the cap exceeds a certain value, the meniscus in the nozzle is broken. Then, after removing the cap, it is necessary to refill the nozzle with ink, clean the nozzle surface, perform preliminary ejection, etc. to form a meniscus, and there is a problem that it takes extra processing and time until the recording operation. is there.

  For example, Japanese Patent Application Laid-Open No. 10-193626 describes a technique for suppressing pressure fluctuation by providing a cap that seals the nozzle surface, but having a structure that is easily deformed in a part of the cap.

JP-A-10-193626

  However, in the conventional technique, since the sealed space is created by the cap, there is always a pressure fluctuation in the cap, and this is suppressed by deformation of the cap. However, at low temperatures, the flexibility of caps made of rubber or the like may be impaired, and the cap cannot be sufficiently deformed, causing a problem of adversely affecting the meniscus. Further, since the part to be deformed has a special structure so as to be easily deformed, there is a problem that the structure of the cap becomes complicated.

  The present invention provides an ink jet printer including a cap that can cap without destroying a meniscus of a nozzle of a recording head and can prevent ink from drying.

  An ink jet printer according to the present invention includes a recording head having a plurality of nozzles for ejecting ink onto a recording medium, a carriage on which the recording head is mounted, and reciprocating in a direction intersecting the conveyance direction of the recording medium; The carriage drive means for driving the carriage and the recording head are arranged corresponding to each of the recording heads, and the tip of the recording head is in contact with the nozzle surface on which the nozzles are arranged to cover the nozzle surface. A cap, a cap unit on which the cap is mounted, and a spring unit that biases the cap in the direction of the nozzle surface; and elevating means for moving the cap unit in the contact / separation direction with respect to the nozzle surface. In the ink jet printer having the cap unit, the cap unit fixes the cap A base portion that supports the cap support portion, the spring is disposed between the base portion and the cap support portion, and the cap support portion is directed to the nozzle surface by the spring. And a protrusion provided on the cap support portion is engaged with a groove portion provided on the base portion, and the cap support portion can move along the groove portion, The direction of movement is a direction in which the cap contacts and separates from the nozzle surface, and the cap is a lip that surrounds the plurality of nozzles when the cap abuts on the nozzle surface of the recording head. And a bag-like part that forms a cap space with the lip part as an opening, and the bag-like part penetrates the inside and outside of the cap space at a position biased to one side in the longitudinal direction of the cap. cap The cap support part has a concave part that accommodates the bag-like part in a state where the lip part is exposed, and is a bottom surface of the concave part, the one side in the longitudinal direction. The cap support part through-hole penetrating the inside and outside of the cap support part at a position biased to the other side direction with respect to the cap, and the position of the bottom face facing the cap, the center of the bottom face in the longitudinal direction A protruding portion provided protruding in the cap direction, and when the cap covers the nozzle, the back side corresponding to the lip portion of the cap and the cap support portion are in close contact with each other The cap space communicates with the outside air through the cap through hole, the space surrounded by the cap, the cap support portion, and the protruding portion, and the cap support portion through hole in order. It is characterized by forming an air opening path through which it passes.

  It is possible to cap without destroying the meniscus of the nozzle of the recording head and to prevent the ink from drying.

FIG. 1 is a cross-sectional view illustrating an example of a cap unit. FIG. 2 is a perspective view illustrating an example of a cap unit. FIG. 3 is a diagram illustrating an example of the cap unit as viewed from above in the opening direction. FIG. 4 is a diagram illustrating a cap fixing portion that fixes the cap. FIG. 5 is a conceptual diagram illustrating an example of an air release route. FIG. 6 is a diagram illustrating the recording head and the cap. FIG. 7 is a diagram for explaining a lifting device for the cap unit. FIG. 8 is a schematic diagram of an ink jet printer. FIG. 9 is a cross-sectional view illustrating another example of the cap unit. FIG. 10 is a diagram illustrating an air release path of another example of the cap unit.

  Hereinafter, embodiments will be described with reference to the drawings. First, the cap unit 1 will be described with reference to FIGS. FIG. 1 is a cross-sectional view illustrating an example of a cap unit. FIG. 2 is a perspective view illustrating an example of a cap unit. FIG. 3 is a diagram illustrating an example of the cap unit as viewed from above in the opening direction. FIG. 4 is a diagram illustrating a cap fixing portion that fixes the cap. FIG. 5 is a diagram for explaining an example of the air release path.

  The cap unit 1 includes, as main components, a cap 25 that contacts the recording head, a cap support portion 26 that supports the cap 25, a base portion 8 that supports the cap support portion 26, a cap support portion 26, and a base. A spring 9 is provided between the base parts 8 and biases the cap support part 26 in a direction away from the base part 8, and a restriction plate 7 that restricts the movement of the cap support part 26 by the spring 9. In order to arrange the spring 9, a part of the cap 25 is shortened from the opening. Therefore, the cap 25 has a shallow portion and a deep portion, and the cap space can be enlarged by forming the deep portion. Since the air release path is thin, long, and has a bent portion, the resistance of the flow path increases. Therefore, even when the pressure in the cap suddenly changes, the cap space capacity is increased, so that the influence on the meniscus can be suppressed. Spaces can be effectively used by disposing the springs 9 at both ends of the lower portion of the cap support portion 26 so as to avoid the springs 9. It is also possible to provide a through hole on the side surface of the bag-like portion 4. In addition, the cap space can be widened. It becomes easy to secure a gap for the air release path between the cap 25 and the cap support portion 26.

  The configuration of the cap 25 includes a lip portion 2 that contacts the nozzle surface of the recording head, a convex portion 3 that fits into the cap support portion 26, and a bag-like portion 4 that creates a space by opening a portion surrounded by the lip portion 2. It is divided into.

  In order to fix the cap 25, the cap support portion 26 is provided with the recess 5 over the entire circumference at the edge of the opening. The concave portion 5 is fixed by fitting the convex portion 3 of the cap 25. In addition, a plurality of fixing holes 19 are provided on the outer side surface of the recess 5 in order to ensure sufficient fixation. The cap 25 is firmly fixed to the cap support portion 26 by fitting the protrusion 18 provided on the side surface of the convex portion 3 into the fixing hole 19. Further, below the portion corresponding to the lip portion 2, there is a protruding portion on one side of the concave portion 5 of the cap support portion 26. When the lip portion 2 comes into contact with the nozzle surface, the lip portion 2 protrudes. It is sandwiched between the part and the nozzle surface and deforms to adhere. At this time, since a force is applied to the back surface below the lip portion 2 in the direction of the cap support portion 26, the back surface of the lip portion 2 and the cap support portion 26 are in close contact with each other.

  The bag-like portion 4 is provided with a cap through-hole 11 that allows air to pass through, and forms a part of the air release path. The position of the cap through-hole 11 serving as a part of the air release path is preferably the side surface of the bag-like portion 4, but may be the bottom of the bag-like portion 4. A plate 15 is disposed on the bottom surface 14 of the opening of the cap support portion 26. The plate 15 is a protruding portion having a flat upper surface at a portion protruding from the bottom surface 14. That is, the plate 15 is a protrusion provided on the bottom surface 14. The plate 15 may be integrally molded with the cap support portion 26 or may be bonded and fixed. When the cap 25 is inserted and fixed to the cap support portion 26, the back side of the bottom of the cap 25 is in close contact with the upper surface of the plate 15. The width of the plate 15 is equal to the width of the bottom surface 14 of the cap support portion 26. The plate 15 has a ventilation groove 27 on the surface. The ventilation groove 27 is bent and disposed so that the path becomes long. For example, the ventilation groove 27 has a zigzag path. The bottom surface of the bottom of the cap 25 is in contact with the plate 15, and the ventilation groove 27 becomes like a tube, which becomes a part of the air release path. By lengthening the path, the movement of the atmosphere is extremely reduced when there is no pressure change, and drying of the cap space can be prevented.

  The bottom surface 14 of the cap support portion 26 is provided with a support portion through hole 12. The cap through-hole 11 and the support portion through-hole 12 are separately arranged at different ends in the longitudinal direction of the cap unit 1. In the example, the cap through-hole 11 and the support portion through-hole 12 are connected to each other by an air release path formed by the plate 15 and the bottom back surface of the cap 25 and the ventilation groove 27 with the plate 15 interposed therebetween.

  The base portion 8 is provided with a first groove 10 and a second groove 21 that restrict the moving direction of the cap support portion 26. Two of these grooves are provided so as to face the center of the short-side wall of the base 8 and to face the center of the long-side wall. The first protrusion 10 of the cap support portion 26 engages with the first groove 10, and the second protrusion 20 of the cap support portion 26 engages with the second groove 21. A spring 9 is fixed to the base portion 8 and is biased toward the cap support portion 26. The restricting plate 7 is engaged with the first groove 10 and the second groove 21 so as to prevent the first protrusion 6 and the second protrusion 20 of the cap support portion 26 from being detached. It is fixed. The cap support portion 26 can move along the first groove 10 and the second groove 21. The four grooves and the four protrusions corresponding thereto move in the direction of contact and separation in parallel with the nozzle surface. That is, it can move without tilting. For example, the cap support portion 26 moves in the direction perpendicular to the nozzle surface, that is, in the direction perpendicular to the nozzle surface. The direction of this movement is the biasing direction of the spring 9 or the direction against the biasing direction. The base portion 8 is provided with a base portion through hole 13 and communicates with the inside and outside. Moreover, the base part 8 is fixed to a lifting device described later by screws 17.

  FIG. 6 is a diagram illustrating the recording head and the cap. The recording head 22 is provided with a plurality of nozzles 23 and ejects ink. When the lip portion 2 of the cap 25 abuts on the nozzle surface on which the nozzle 23 is provided, a space is created in the cap and the outside air is blocked. However, the inside and outside are communicated through the cap through-hole 11 instead of being completely shut off. This eliminates the pressure difference between the inside and outside. The cap 25 moves in the direction of the arrow 24. This movement also eliminates the pressure difference between the inside and outside of the cap space because the inside and outside communicate with each other.

  FIG. 7 is a diagram for explaining a lifting device for the cap unit. The cap unit 1 that caps the recording head can be moved up and down by the lifting device 30 so that the lip 2 of the cap 25 can be brought into contact with the recording head.

  The cap unit 1 is attached to the base 32. The base portion 8 is fixed to the base 32 with screws 17. The base 32 includes seven cap units 1. The cap unit 1 is provided for the number of recording heads. The rotation of the elevating motor 31 is converted into a vertical motion via a cam, and the base 32 is raised and lowered. As a result, the lip portion 2 of the cap unit 1 can be brought into and out of contact with the recording head.

  FIG. 8 is a schematic diagram of an ink jet printer. The ink jet printer 40 includes a platen 43. The platen 43 is a flat plate that supports a recording medium transported by transport rollers 44 arranged in the longitudinal direction of the ink jet printer 40 on a flat surface. Although not shown, there are a large number of holes on the surface, and the recording medium is adsorbed on the surface of the platen 43 by suction. A carriage 47 reciprocates along the platen 43. An ink jet recording head is mounted on the carriage 47 and ejects ink onto a recording medium supported by the platen 43. The recording medium is paper, a resin film made of vinyl chloride, or the like. The recording unit 41 includes a carriage 47 and a recording head mounted on the carriage 47. The carriage 47 reciprocates in the direction intersecting the recording medium conveyance direction. For example, the directions are orthogonal.

  The rail 46 is a linear rail disposed along the longitudinal direction of the inkjet printer 40. The carriage 47 moves along the rail 46. The carriage 47 is fixed to the belt 45. The belt 45 is driven by a drive motor 42. The belt 45 is an endless belt that is wound around pulleys disposed on both sides of the rail 46, and is driven by the drive motor 42 to move the carriage 47 along the rail 46. A linear scale (not shown) is arranged along the rail 46, and a sensor for detecting the scale of the scale is mounted on the carriage 47. The scale is detected by the sensor, and the position of the carriage 47 can be detected. Since the position of the moving carriage 47 can be detected, ink can be ejected according to the position and a desired image can be recorded on the recording medium.

  The wipe unit 48 is a device that wipes the nozzle surface of the recording head mounted on the carriage 47 with a wiper. It is arranged on the side of the platen 43. The carriage 47 is moved onto the wipe unit 48, the wiper is moved along the longitudinal direction of the recording head, and the nozzle surface is wiped off. In this example, wipers corresponding to the number of recording heads are provided. The nozzle surface can be cleaned by the wiper. By capping after ejecting ink or cleaning the nozzle surface, the cap can be capped after removing thickened ink and the like, and the effect of preventing drying during capping is enhanced. For this reason, one may be used, but it is preferable to cap after ink ejection and after cleaning the nozzle surface. Furthermore, it is preferable to periodically clean and discharge ink.

  A lifting device 30 to which the cap unit 1 is attached is disposed on the side of the platen 43. This is a different side from the wipe unit 48. The carriage 47 can be capped by moving the carriage 47 so that the cap unit 1 is positioned directly below each recording head and raising the carriage 47 by the lifting device 30.

  Next, another example of the cap unit will be described with reference to FIGS. FIG. 9 is a cross-sectional view illustrating another example of the cap unit. FIG. 10 is a diagram illustrating an air release path of another example of the cap unit.

  A cap through hole 51 is provided on the side surface of the bag-like portion 4 of the cap 25. A portion protruding from the side surface is provided on the entire circumference of the inner edge of the bag-like portion 4 of the cap through-hole 51. Even if the ink drips from the nozzle into the cap through-hole 51, since the protruding portion is present, the ink flows along the protruding portion so that the cap through-hole 51 is not filled with the ink.

  A plate 50 is disposed on the bottom surface 14 of the opening of the cap support portion 26. That is, the plate 50 is a protruding portion provided on the bottom surface 14. The width of the plate 50 is the same as the width of the bottom surface 14. The cap support part 26 and the plate 50 may be integrated. The back surface of the bottom surface of the bag-like portion 4 of the cap 25 is in contact with the plate 50. However, if the cap 25 does not match the shape formed by the cap support 26 and the plate 50, a gap 51 is generated. Therefore, the gap 51 is used as part of the air release path. There is no need to provide a groove in the plate 50. Further, the length of the plate 50 in the longitudinal direction is increased to replace the groove.

  The back side of the lip portion 2 of the cap 25 is at a position corresponding to the protruding portion 52 of the concave portion 5 of the cap support portion 26. A lip portion 2 is provided on the edge of the opening over the entire circumference. Correspondingly, the recess 5 is also provided on the entire circumference along the opening of the cap support portion 26. When the lip portion 2 comes into contact with the nozzle surface, the lip portion 2 is sandwiched between the protruding portion 52 and the nozzle surface, deforms, and comes into close contact. At this time, the back surface below the lip portion 2 is in close contact with the protruding portion 52 because a force is applied in the direction of the cap support portion 26. Air is less likely to leak into and out of this part. Further, even if the plate 50 is not provided with a groove, the air release path can be narrowed and lengthened, and the configuration is simple.

  The present invention can be used for an ink jet printer.

DESCRIPTION OF SYMBOLS 1 Cap unit 2 Lip part 3 Projection part 4 Bag-like part 5 Concave part 6 1st protrusion 7 Control plate 8 Base part 9 Spring 11 Cap through-hole 14 Bottom face 15 Plate 17 Screw 18 Projection part 19 Fixing hole 20 2nd protrusion 22 Recording head 22
23 Nozzle 25 Cap 26 Cap support portion 27 Ventilation groove 30 Lifting device 31 Lifting motor 32 Base 40 Inkjet printer 47 Carriage

Claims (4)

A recording head comprising a plurality of nozzles for ejecting ink onto a recording medium;
A carriage on which the recording head is mounted, and reciprocating in a direction intersecting the conveyance direction of the recording medium;
Carriage driving means for driving the carriage;
A cap that is disposed corresponding to each of the recording heads, and that covers the nozzle surface by abutting the tip of the nozzle on which the nozzle of the recording head is disposed;
Said cap is mounted, and a cap unit provided with a spring that urges the cap in the direction of the nozzle surface,
In an inkjet printer having an elevating means for moving the cap unit in the contact / separation direction with respect to the nozzle surface,
The cap unit has a cap support part that fixes the cap, and a base part that supports the cap support part,
Before fang Ne is disposed between the cap support portion and the base portion, the cap support portion is biased in the direction of the nozzle surface by the pre-Fang Ne,
A protrusion provided on the cap support part is engaged with a groove part provided on the base part, and the cap support part can move along the groove part, and the direction of the movement is determined by the cap. Is the direction of contact with and away from the nozzle surface,
The cap has a lip portion surrounding the plurality of nozzles when the cap abuts against a nozzle surface of the recording head, and a bag-shaped portion that forms a cap space having the lip portions as openings. And
The bag-like portion includes a cap through-hole penetrating the inside and outside of the cap space at a position biased to one side in the longitudinal direction of the cap,
The cap support portion has a concave portion that accommodates the bag-shaped portion with the lip portion exposed, and is a bottom surface of the concave portion, and is biased toward the other side with respect to the one side in the longitudinal direction. A cap support part through-hole penetrating the inside and outside of the cap support part, and a position facing the cap on the bottom surface, and projecting in the cap direction at the longitudinal center of the bottom surface And a protruding portion,
When the cap covers the nozzle, the back side corresponding to the lip portion of the cap and the cap support portion are in close contact, and the cap through hole, the cap, the cap support portion, and the protrusion An ink jet printer, wherein an air release path communicating from the cap space to the outside air is formed in order through a space surrounded by the portion and the cap support portion through hole.   2. A groove is formed on a side of the projecting portion facing the cap, the cap and the projecting portion are in close contact, and the groove is a part of the atmosphere release path. The inkjet printer as described in.   The side of the protruding portion facing the cap is formed in a flat shape, and a gap is formed in a portion surrounded by the cap, the protruding portion, and the cap support portion, and the gap is the air release path. The inkjet printer according to claim 1, wherein the inkjet printer is a part of the inkjet printer.   The concave portion is formed in the cap support portion in a ring shape, and the edge of the cap is fitted in the concave portion over the entire circumference. Inkjet printer.

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