This application claims priority from Japanese Patent Application No. 2005-380151 filed Dec. 28, 2005. The entire content of priority application is incorporated herein by reference.
The present invention relates to a maintenance unit for a droplet ejecting device, and to a droplet ejecting device employing the maintenance unit.
An inkjet recording device well known in the art records print data on a recording paper by pressurizing ink in a pressurizing chamber to eject ink droplets from nozzles onto the recording paper. Many issues leading to printing inconsistencies can arise in this inkjet recording device, including viscosity build-up in the ink caused by ink solvent evaporating from the nozzles, the solidification of the ink, dust deposits, and air bubbles in the ink near the nozzles.
Therefore, this type of inkjet recording device normally has a maintenance unit including capping unit for sealing the nozzles in the recording head when not printing, and cleaning unit for cleaning a nozzle plate as needed.
For example, an ink jet recording device includes a capping unit disposed outside a printing range and including a cap that moves from a standby position to a contact position when pressed by a recording head or a carriage supporting the recording head, and a four-joint parallel linkage mechanism for moving the cap toward the nozzle plate side of the recording head as the recording head moves from the standby position to the contact position.
As shown in
The linking mechanism 342 includes two link members 342a and 342b with engaging holes formed on both ends thereof. An end of each link member 342a and 342b is pivotably fixed to the capping base 311, while the other end of each link member 342a and 342b is pivotably fixed to the cap 341.
As shown in
With this construciton, the right end of the recording head 310 contacts the receiving plate 344 when the recording head 310 moves outside the printing range (toward the right in
Conversely, when the recording head 310 moves toward the printing area (leftward in
However, when moving the cap 341 vertically to seal the nozzles in the recording head 310, as described above, a sufficient stroke (where L is a length of a stroke and will be referred to as the stroke L hereafter) must be provided for the vertical movement of the cap 341 in order to prevent the cap 341 from impeding the movement of the recording head 310 and to press the cap 341 against the nozzles in a direction orthogonal to a droplet ejecting direction.
One method of obtaining this stroke L is to shorten link member length of the four-joint parallel linkage mechanism 342 and to reduce a height of the cap 341 support part 312 formed on the capping base 311 in order to reduce angle a in the four-joint parallel linkage mechanism 342 at the standby position. In other words, the four-joint linkage mechanism 342 is laid downward.
However, as illustrated in
In order to avoid this problem, link members 442a and 442b of a four-joint parallel linkage mechanism 442 may be increased in length, as illustrated in
However, since the length of the link members 442a and 442b are increased with this method, vertical dimension of the linkage mechanism 442 is increased, necessitating an increased size in the maintenance unit. In turn, this leads to an increased size in the inkjet printer.
In view of the foregoing, it is an object of the present invention to provide a maintenance unit for a droplet ejecting device that is compact and capable of reliably capping the recording head.
To achieve the above and other objects, one aspect of the invention provides maintenance unit for a droplet ejecting device including a base frame, a sealing unit, a guiding mechanism, and a supporting part. The sealing unit is provided on the base frame and capable of sealing nozzles formed in a droplet ejecting head mounted on a carriage. The carriage reciprocates between a droplet ejecting region for ejecting droplets from the nozzles in the droplet ejecting head onto a recording medium and a maintenance region for cleaning the nozzles in the droplet ejecting head. The sealing unit being located on the maintenance region. The guiding mechanism is interposed between the base frame and the sealing unit and capable of moving the sealing unit in association with a reciprocating motion of the carriage between a first position in which the sealing unit seals the nozzles and a second position in which the sealing unit separates from the nozzles. The guiding mechanism includes a first engaging part and a second engaging part. The first and second engaging parts are coupled to the sealing unit. The second engaging part is provided at a side closer to the droplet ejecting region than the first engaging part. The first and second engaging parts are movable according to positions of the sealing unit. The supporting part supports the sealing unit and is interposed between the sealing unit and the base frame. The supporting part is in a position either just below the first engaging part or at a side farther from the droplet ejecting region than the first engaging part when the sealing unit is in the second position.
In another aspect of the invention, there is provided droplet ejecting device including a droplet ejecting head, a carriage, a recording medium moving unit, and the maintenance unit described above.
In another aspect of the invention, there is provided a maintenance unit for a droplet ejecting device, including a sealing unit, and a guiding mechanism. The sealing unit is capable of sealing nozzles formed in a droplet ejecting head mounted on a carriage. The carriage reciprocates between a droplet ejecting region for ejecting droplets form the nozzles in the droplet ejecting head onto a recording medium and a maintenance region for cleaning the nozzles in the droplet ejecting head. The sealing unit is located on the maintenance region. The guiding mechanism is capable of moving the sealing unit in association with a reciprocating motion of the carriage between a first position in which the sealing unit seals the nozzles and a second position in which the sealing unit separates from the nozzles. The sealing unit includes a contact portion upon which the carriage impinges when the carriage moves from the droplet ejecting region to the maintenance region. The contact portion is configured to apply pushing force to the sealing unit in a direction from the second position to the first position when the carriage impinges upon the contact portion and apply push force thereupon.
In another aspect of the invention, there is provided droplet ejecting device including a droplet ejecting head, a carriage, a recording medium moving unit, and the maintenance unit described above.
In the drawings:
Next, a droplet ejecting device according to preferred embodiments of the present invention will be described while referring to the accompanying drawings. The droplet ejecting device of the present invention is applied to an inkjet printer.
Next, a first embodiment of the present invention will be described with reference to
<General Structure of an Inkjet Printer>
First, the general structure of an inkjet printer 101 will be described with reference to
The inkjet printer 101 of the preferred embodiment has a printer function, copier function, and scanner function. As shown in
A discharge tray 6 and a feeding tray 7 are provided in the front surface of the body frame 1. The carriage 3 is capable of reciprocating in the left-to-right direction, and a range in which the carriage 3 reciprocates from a left end of a reciprocating path to a position near a right end is a recording range 8. A region on a right end of the reciprocating path is a maintenance position 9, which may also be referred to as a point of origin or a home position of the carriage 3. The maintenance unit 4 is disposed in this maintenance position 9.
The ink tanks 5 (ink cartridges) provided for each of the colors black, cyan, magenta, and yellow are juxtaposed in front side of the maintenance position 9 toward the front of the inkjet printer 101 (the near side in
<The Carriage and a Unit for Supplying Ink Thereto>
Next, the carriage 3 and a unit for supplying ink to the carriage 3 will be described with reference to
The carriage 3 has four recording heads 10, although only one is shown in
A buffer tank 11 is provided on a top surface of each recording head 10. The buffer tank 11 has an air bubble retention chamber 12 in the top section thereof, and an ink chamber 13 in fluid communication with the recording head 10 provided in a bottom section thereof. Flexible tubes 14 (see
Ink supplied to each air bubble retention chamber 12 flows into the ink chamber 13 after passing through a filter 15 and is guided along the ink chamber 13 into the recording head 10. Air bubbles are filtered from the ink as the ink passes through the filter 15 and are retained in an upper region of the air bubble retention chamber 12.
A valve case 16 is provided in the carriage 3 to the front of the recording head 10. A discharge path 17 extends from an upper wall of each air bubble retention chamber 12 to a discharge opening 18 formed in a bottom surface 16A of the valve case 16. The four discharge openings 18 are formed on the bottom surface 16A of the valve case 16 and correspond to the four recording heads 10. The four discharge paths 17 extend vertically within the valve case 16. Shutoff valves 19 that are normally closed are housed in vertically extending sections of the discharge paths 17.
More specifically, each shutoff valve 19 includes a valve port 22, and a slender valve plug 20 extending vertically for plugging the valve port 22. A spring 21 urges the valve plug 20 into the valve port 22 so that the shutoff valve 19 is normally maintained in a closed state. The shutoff valve 19 can be opened by moving the valve plug 20 upward against an urging force of the spring 21.
<Drive Transmitting Mechanism for the Maintenance Unit>
Next, a drive transmitting mechanism for the maintenance unit 4 will be described with reference to
As shown in
A reduction gear 25 is engaged with an output shaft of the motor 24. The reduction gear 25 is mounted on a rotational shaft 26 extending to the right. A drive gear 27 is provided on a right end of the rotational shaft 26 and is capable of rotating integrally therewith. A sliding gear 29 is engaged with the drive gear 27. The sliding gear 29 also engages with a large-diameter bevel gear 28 only when the carriage 3 moves into the maintenance position 9. The large-diameter bevel gear 28 engages with a small-diameter bevel gear 30, having a vertically oriented axis, in the maintenance unit 4.
The small-diameter bevel gear 30 is engaged with a solar gear 32 via a reduction gear 31 (see
A disc-shaped cam 55 is supported on the front side of the planetary gear 35 on a maintenance frame 111 so as to be freely rotatable. An axis of the cam 55 is vertically oriented and parallel to axes of the solar gear 32 and planetary gear 35. A driven gear 36 positioned at a same height as the planetary gear 35 in the vertical direction is integrally formed on the cam 55.
A pump gear 37 positioned at a same height as the planetary gear 35 in the vertical direction is supported on the maintenance frame 111 rearward of the planetary gear 35 so as to be freely rotatable. By rotating, the pump gear 37 drives a rotary pump 38 to execute a suction operation.
When the solar gear 32 rotates counterclockwise in
On the other hand, when the solar gear 32 rotates clockwise, the planetary gear 35 rotates counterclockwise while revolving clockwise about the solar gear 32 and engages with the pump gear 37. The planetary gear 35 drives the rotary pump 38 to rotate and perform a suction operation
<A Cap Lift Holder of the Maintenance Unit>
Next, a cap lift holder 41 of the maintenance unit 4 will be described with reference to
The cap lift holder 41 is movably disposed on the maintenance frame 111. As shown in
More specifically, the first link member 42a includes one end portion 42c and another end portion 42d. The one end portion 42c of the first link member 42a is pivotably fixed to the cap lift holder 41 on a first engaging part 47a. The another end portion 42d of the second link member 42a is pivotably fixed to the maintenance frame 111 on a first fixed part 47b. The first engaging part 47a is positioned on the recording range 8 side (left side) of the first fixed part 47b when the cap lift holder 41 is in the standby position. The second link member 42b includes one end portion 42e and another end portion 42f. The one end portion 42e of the second link member 42b is pivotably fixed to the cap lift holder 41 on a second engaging part 47c. The another end portion 42f of the second link member 42b is pivotably fixed to the maintenance frame 111 on a second fixed part 47d. The second engaging part 47c is positioned on the recording range 8 side (left side) of the second fixed part 47d when the cap lift holder 41 is in the standby position. The second engaging part 47c is positioned on the recording range 8 side (left side) of the first engaging part 47a.
The first engaging part 47a, first fixed part 47b, second engaging part 47c, and second fixed part 47d are positioned so that the first and second link members 42a and 42b are parallel to each other when linked to these components.
The cap support part 112 provided on the maintenance frame 111 is disposed at the position of the first engaging part 47a or toward the point of origin side (right side) from the first engaging part 47a. The cap support part 112 supports a right lower end of the cap lift holder 41 when the cap lift holder 41 is in the standby position.
A pair of receiving plates 44 extend upward from a right edge of the cap lift holder 41 (see
As shown in
<Nozzle Cap of the Maintenance Unit>
Next, the nozzle cap 60 of the maintenance unit 4 will be described with reference to
The nozzle cap 60 is provided on the cap lift holder 41 in a region to the left of an exhaust cap 40. The nozzle cap 60 is capable of moving vertically relative to the cap lift holder 41 through a spring (not shown). The nozzle cap 60 is formed of a silicon rubber in a rectangular shape extending in the front-to-rear direction (orthogonal to the surface of the drawing). Left and right recessed parts are formed in a top surface 60A of the nozzle cap 60. The top surface 60A of the nozzle cap 60 is substantially parallel to the bottom surface 10A of the recording head 10. Spacers 62 having a semicircle cross section and curved surfaces facing upward are accommodated in the two recessed parts.
When the cap lift holder 41 is in the standby position, the nozzle cap 60 is maintained at a lower height than the bottom surface 10A of the recording head 10. As the carriage 3 presses against the cap lift holder 41, moving the cap lift holder 41 upward and rightward toward the contact position, rib parts formed on the upper edges of the nozzle cap 60 contact the bottom surface 10A of the recording head 10 to form an airtight state that is enhanced by the urging force of the spring (not shown).
Through this contact, the top surfaces of the spacers 62 provided on the nozzle cap 60 and the bottom surface 10A of the recording head 10 simultaneously configure independent left and right hermetically sealed spaces that are in communication with the nozzles in the recording head 10 (see
As shown in
Each hermetically sealed space is formed such that the vertical clearance is smallest in the left-to-right center and gradually increases toward both left and right sides. Accordingly, when the hermetically sealed space is set to a negative pressure to draw ink from the nozzles through the inlet 64 by the rotary pump 38, a flow of air (including ink) from the left-to-right center toward both left and right sides having a smaller flow resistance is produced substantially uniformly across the front-to-rear direction. This airflow combines with the flow in the left and right sides of the hermetically sealed space to produce a larger flow toward the inlet 64, thereby drawing air into the inlet 64.
Hence, even when the inlet 64 is provided on the front end of the hermetically sealed space elongated in the front-to-rear direction, a uniform airflow is produced across the entire range so that ink can be purged uniformly from all nozzles.
Further, as shown in
<Operations of the Cap Lift Holder>
Next, the operations of the maintenance unit 4 during movement of the carriage 3 will be described with reference to
As shown in
At this point, both the exhaust cap 40 and the nozzle cap 60 are positioned below the bottom surface 10A of the recording head 10 and, hence, do not contact (are separated from) the bottom surface 10A of the recording head 10.
As the recording head 10 moves toward the point of origin (right side) from this state, the cap lift holder 41 supported by the first and second link members 42a and 42b begins to move upward to the right. At this time, depending on the lengths of the two link members 42a and 42b and the positions of the first and second engaging parts 47a and 47c when the cap lift holder 41 is in the standby position, a pushing force in a direction downward to the left could be applied to the first engaging part 47a, while a pulling force in a direction upward to the right could be applied to the second engaging part 47c.
In this situation, the first link member 42a is pushed downward, preventing the cap lift holder 41 from moving upward to the right. Accordingly, the cap lift holder 41 could become immovably stuck in an inclined position/state. In a worst case, the cap lift holder 41 could become unable to return to its original position/state.
However, since the lower right edge of the cap lift holder 41 is supported on the cap support part 112, as shown in
When the recording head 10 moves further toward the point of origin while the cap lift holder 41 supported on the cap support part 112 at the lower right edge thereof is maintained at this uniform height from the maintenance frame 111, a pulling force in a direction upward to the right begins to be applied to the first engaging part 47a.
Specifically, since the cap support part 112 is disposed at the position of the first engaging part 47a or nearer to the point of origin than the first engaging part 47a, the first link member 42a cannot be pushed downward. Therefore, the recording head 10 can move toward the point of origin. As the recording head 10 moves farther toward the point of origin, a pulling force upward to the right becomes applied to both the first and second engaging parts 47a and 47c, thereby reliably moving the cap lift holder 41 along an arcing path upward to the right so that the cap lift holder 41 is moved to the contact position. Since the pulling force is applied to the first and second engaging parts 47a and 47c, the cap lift holder 41 can be moved from the standby position to the contact position without changing in the orientation of the cap lift holder 41 When the cap lift holder 41 moves to the contact position, the nozzle cap 60 contacts the bottom surface 10A of the recording head 10 from the bottom thereof. As the carriage 3 moves farther rightward, the pushing spring (not shown) provided between the upward moving cap lift holder 41 and the nozzle cap 60 contacting the bottom surface 10A of the recording head 10 elastically contracts. An elastic restoring force of the pushing spring pushes the nozzle cap 60 firmly against the recording head 10, as shown in
As the carriage 3 continues to move rightward and arrives at the point of origin, the exhaust cap 40 contacts the bottom surface 16A of the valve case 16, as shown in
With the maintenance unit 4 having the structure described above, the top surface 60A of the nozzle cap 60 provided on the cap lift holder 41 is substantially parallel to the bottom surface 10A and is substantially orthogonal to the direction in which ink is ejected from the nozzles when in the standby position and the cap lift holder 41 can be moved from the standby position to the contact position without changes in the orientation of the cap lift holder 41. Accordingly, the top surface 60A of the nozzle cap 60 can easily seal the nozzles in the bottom surface 10A while substantially orthogonal to the direction of ink ejection.
Since the nozzles can be sealed with the top surface 60A oriented substantially orthogonal to the direction of ink ejection, an excellent seal can be formed between the nozzles and the nozzle cap 60. Further, since the nozzle cap 60 does not contact the nozzles in a transverse direction (in a parallel direction with respect to the top surface 60A) to the nozzles, the nozzle cap 60 does not damage the nozzles.
The cap support part 112 is provided closer to the point of origin than the first engaging part 47a in the standby position. Accordingly, the cap lift holder 41 is supported on the cap support part 112 even when a force toward the first fixed part 47b is applied to the first engaging part 47a. Therefore, since the cap lift holder 41 does not move farther downward toward the maintenance frame 111, the cap lift holder 41 does not become immovably stuck in the inclined position/state.
Since the cap lift holder 41 does not become immovably stuck in the inclined position/state, the recording head 10 can move farther toward the point of origin. As the recording head 10 moves farther toward the point of origin while the cap lift holder 41 is supported on the cap support part 112, a force pushing the first engaging part 47a away from the maintenance frame 111 is applied to the first engaging part 47a, ultimately enabling the cap lift holder 41 to move toward the recording head 10. As a result, the nozzle cap 60 of the cap lift holder 41 can seal the nozzles.
Hence, the maintenance unit 4 having this construction can reliably seal the nozzles in the recording head 10, regardless of the positions of the first and second engaging parts 47a and 47c relative to a direction orthogonal to the moving direction of the recording head 10.
In other words, the first and second engaging parts 47a and 47c can be positioned near the recording head 10 when the in the cap lift holder 41 is in the standby position, reducing the required lengths of the link members 42a and 42b. Consequently, the maintenance unit 4 can be made more compact.
Further, since the maintenance unit 4 can be made more compact, the inkjet printer 101 incorporating the maintenance unit 4 can also be made more compact.
Further, in the maintenance unit 4, since the cap lift holder 41 does not become immovably stuck in the inclined position/state as the cap lift holder 41 moves, an excessive load is not placed on a motor or other driving device provided for driving the carriage 3 mounted on the recording head 10 as the recording head 10 pushes the cap lift holder 41. Hence, a smaller motor can be used for driving the carriage 3, which can also lead to a more compact inkjet printer 101. Further, this configuration can extend the life of the driving device.
Further, since the cap lift holder 41 can move smoothly toward the contact position as the recording head 10 moves toward the point of origin, a small amount of energy is required for moving the cap lift holder 41. More specifically, the driving device for driving the carriage does not require a large force for moving the carriage 3 to the point of origin, enabling the carriage 3 to be provided with a small driving device having a low output.
Next, a second embodiment of the present invention will be described with reference to
By sloping the sloped surface 144A of the receiving plate 144 of the cap lift holder 41 toward the recording head 10 in this way, the recording head 10 contacts the sloped surface 144A when moving toward the point of origin.
Since the sloped surface 144A is inclined gradually leftwardly toward the top side in
When this pulling force is applied to the first and second engaging parts 47a and 47c, the cap lift holder 41 can move smoothly toward the contact position as the recording head 10 moves toward the point of origin. Accordingly, the cap lift holder 41 does not become immovably stuck in the inclined position/state.
In other words, as with the cap lift holder 41 of the first embodiment, it is possible to move the cap lift holder 41 smoothly from the standby position to the contact position, regardless of the length of the two link members 42a and 42b. Hence, the link members 42a and 42b can be shortened to reduce the size of the maintenance unit 4.
Further, since the maintenance unit 4 can be made more compact, the inkjet printer 101 incorporating the maintenance unit 4 can also be made more compact.
Further, in the maintenance unit 4, since the cap lift holder 41 does not become immovably stuck in the inclined position/state as the cap lift holder 41 moves, an excessive load is not placed on the motor or other driving device provided for driving the carriage 3 mounted on the recording head 10 as the recording head 10 pushes the cap lift holder 41. Hence, a smaller motor can be used for driving the carriage 3, which can also lead to a more compact inkjet printer 101.
While the invention has been described in detail with reference to specific embodiments thereof, it would be apparent to those skilled in the art that many modifications and variations may be made therein without departing from the spirit of the invention, the scope of which is defined by the attached claims.
For example, a four-joint parallel linkage mechanism is used in the embodiments described above to move the cap lift holder 41 from the standby position to the contact position. However, a cam mechanism may be used in place of the linkage mechanism. More specifically, as shown in
First and second engaging parts 147a and 147c corresponding to the first and second engaging parts 47a and 47c in the embodiments described above are provided in shape of bosses that protrude out from the cap lift holder 41. The first engaging part 147a is inserted into the guiding groove 114a, while the second engaging part 147cis inserted into the guiding groove 114b. As with the embodiments described above, the cap support part 112 supports a right lower end of the cap lift holder 41 when the cap lift holder 41 is in the standby position.
As with the four-joint parallel linkage mechanism 42 in the embodiments described above, this construction can move the cap lift holder 41 via the guiding grooves 114a and 114b from the standby position to the contact position. Accordingly, the cap lift holder 41 does not become immovably stuck in the inclined position/state.
Alternatively, it is possible to combine the cam mechanism and linkage mechanism, as shown in
As with the four-joint parallel linkage mechanism in the embodiments described above, this construction can also move the cap lift holder 41 via the first link member 42a and the guiding groove 114b from the standby position to the contact position. Accordingly, the cap lift holder 41 does not become immovably stuck in the inclined position/state.
Further, in each of the embodiments described above, the cap support part 112 is provided on the maintenance frame 111. However, the same effects can be achieved by providing the cap support part 112 on the cap lift holder 41,
In the preferred embodiments described above, the droplet ejecting device is applied to an inkjet printer. However, the droplet ejecting device may also be a lens manufacturing apparatus or the like. In such a case, liquid resin may be used in place of the ink and a resin board in place of the recording medium, for example. The lens manufacturing device can produce resin lenses by ejecting the liquid resin from the recording head 10 onto the resin board to form convex or concave surfaces thereon.
Various droplet ejecting devices can be configured to eject a liquid stored in subtanks as droplets from the nozzles, as in a soldering apparatus for automatically soldering various printed circuit boards or the like by ejecting molten solder from the nozzles, apparatuses that form an organic film used to produce organic EL displays by ejecting an organic polymer material (illuminant) according to the inkjet method, or apparatuses for ejecting resin in a slurry form from the nozzles.
Number | Date | Country | Kind |
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2005-380151 | Dec 2005 | JP | national |