Cleaning device for cleaning printhead of ink-jet printer

[0001] The present invention relates to a cleaning device for cleaning a printhead of an ink-jet printer that carries out printing by ejecting ink droplets onto a recording medium.

[0002] The ink-jet printer ejects ink droplets onto a recording medium from a plurality of nozzles formed on an ink ejecting surface of a printhead by applying instantaneous pressure to the ink within the nozzles. The instantaneous pressure is generated, for example, by elements that convert electrical energy into mechanical energy, such as a piezoelectric element, or elements that convert electrical energy into heat.

[0003] The ink-jet printer prints characters and images by ejecting ink droplets onto the recording medium and thereby forming a plurality of small dots thereon. A great advantage of such an ink-jet printer is that it can provide a highquality color image printer of a relatively simple structure by ejecting different color inks from different nozzles of the printhead. However, It should be noted there are also some problems typical among ink-jet printers.

[0004] One of such typical problems is that the ink adheres to the ink ejecting surface or nozzles of the printhead during the printing operation.

[0005] The ink adheres to the ink ejecting surface or nozzles when bubbles are generated in the ink within or near the nozzles due to temperature increase within the printer as a result of a long, continuous use thereof. These bubbles not only hinder the ink droplets ejected from the nozzles to fly toward the recording medium along expected trajectories, which causes deterioration of printing quality, but also atomize the ejected ink. The atomized ink suspends in the vicinity of the ink ejecting surface, instead of flying toward the recording medium, and a part of them adheres to the ink ejecting surface or nozzles.

[0006] The adherence of ink to the ink ejecting surface or nozzles may occur even if the bubble mentioned above are not generated. For example, some of the ejected ink droplet bounces back from the recording medium and adheres to the ink ejecting surface.

[0007] If the printer is not used for a long time with the adhered ink left on the ink ejecting surface or at the nozzle opening, the nozzle will be clogged with dried ink. Once the nozzle is clogged, the print quality begins to fade or it becomes unprintable since the amount of ejected ink decreases or no ink can be ejected.

[0008] The clogging of the nozzle with dried ink cannot be removed by merely applying pressure to the ink with the piezoelectric element or heating element mentioned above. Therefore, various methods for preventing or removing the clogging of the nozzle are provided.

[0009] Typical methods for preventing or removing clogging of the nozzle include capping, wiping, ink suction, and preparative ink discharge (or flushing).

[0010] In capping, the ink ejecting surface of the printhead is tightly covered with a rubber cap member to prevent drying of the ink. The cap member covers the ink ejecting surface, for example, when the ink-jet printer is not in use for a long time, or, over the interim time period between one printing cycle and another.

[0011] In wiping, the ink ejecting surface of the printhead is rubbed with a blade like member at a predetermined timing or predetermined interval to wipe the ink ejecting surface clean.

[0012] In ink suction, the ink is removed from the nozzle under suction at a predetermined interval, timing, or step. In preparative ink discharge or flushing, minute dust of paper and/or fiber, for example, and small ink clots are removed from the nozzles by flushing ink from the nozzles.

[0013] It should be noted that one or a combination of the above-mentioned methods are typically used in the inkjet printer to prevent the clogging of the nozzles of the printhead.

[0014] If wiping is carried out, the blade should be cleaned to remove the ink adhered thereto. Otherwise, the wiping becomes ineffective or ink remaining thereon drops down and makes the printer dirty. Typically, the ink remaining on the blade is removed by bringing the blade into contact with an ink absorber, or by utilizing the springing back of the blade after being bent.

[0015] Devices that prevent or remove clogging of the nozzle by practicing the above-mentioned methods are called cleaning devices or recovering devices. Such cleaning (recovering) devices are essential for the ink-jet printer to maintain high quality printing.

[0016] The ink-jet printer disclosed in the above-mentioned Japanese Patent Publication, however, requires much time for the cleaning operation since the printhead is once moved out of the printing area, for allowing wiping of the ink ejecting surface with the cleaning blade, and then moved back to the printing area for allowing the cleaning blade returning to the initial position without coming into contact with the printhead.

[0017] Japanese Patent Application Provisional Publication HEI 11-138857 discloses an ink-jet printer in which a cleaning blade wipes off an ink ejecting surface of a printhead, and then moves toward an ink absorber so as to remove the ink adhered to the tip portion thereof by rubbing the tip portion against the ink absorber. The cleaning blade is bent by the ink absorber, springs back as it leaves the ink absorber and thereby scatters or removes the ink adhered to cleaning blade at portions other than the tip portion. The cleaning blade is placed in a blade holder that is coupled to a disk via a link mechanism. The disk rotates to move the blade holder, and hence the cleaning blade, up and down. After the ink adhered to the cleaning blade is removed, the cleaning blade is moved down by rotating the disk so that the cleaning blade does not come into contact with the ink ejecting surface.

[0018] Since the printer disclosed in the above mentioned publication lifts the cleaning blade up when the ink ejecting surface of the printhead is to be wiped, and moves down the cleaning blade when the cleaning blade is to be returned to the initial position, the printer requires a complicated mechanism that utilizes a rotating disk to move up and down the blade holder and also an additional motor for driving the disk.

[0019] Therefore, there is a need for a cleaning device that is capable of cleaning a printhead of an ink-jet printer with a simple structure.

[0020] The present invention is advantageous in that a cleaning device for cleaning a printhead of an ink-jet printer is provided that satisfy the above-mention needs.

[0021] According to an aspect of the invention, a cleaning device for cleaning a printhead of an ink-jet printer is provided that includes a cap member, a cleaning unit and an ink absorber. The cap member is formed to cover the printhead by coming into close contact with the printhead and receive waste ink discharged from the printhead. The cleaning unit is provided with a cleaning blade which removes ink adhered to the printhead. The ink absorber is provided to absorb ink adhered to the cleaning blade.

[0022] First and second vents are provided to the cap member and the ink absorber, respectively. A suction device is connected to the first and second vents. Waste ink received in the cap member or absorbed into the ink absorber is remove from the cap member and the ink absorber through the first and seconds vents, respectively, by suction.

[0023] The cleaning device is further provided with a first moving mechanism connected to the cap member and a second moving mechanism connected to the cleaning unit. The second moving mechanism reciprocates the cleaning blade in parallel with an ink ejecting surface of the printhead. The first moving mechanism moves the cap member between first and second positions. At the first position, the cap member comes into close contact with the printhead to cover the printhead. At the second position, the cap member is placed apart form the printhead.

[0024] The cleaning device is further provided with a first power transmission mechanism selectively connected to one of the first and second moving mechanisms, for example, by means of a planet gear, and a first driving device connected to the first power transmission mechanism to provide driving force through the first power transmission mechanism to one of the first and second moving mechanisms. Since the first and second moving mechanism is driven by a common driving device, the cleaning device can be made compact.

[0025] Optionally, the first driving device includes a source of power that generates driving force for both of the first and second moving mechanisms.

[0026] Optionally or alternatively, the cleaning device further includes a source of power that generates driving force for both of the suction device and the first power transmission mechanism.

[0027] Optionally or alternatively, the suction device Includes a suction pump, a plurality of valve mechanisms arranged to selectively connect one of the first and second vents with the suction pump, and a source of power that generates driving force for both of the suction pump and the plurality of valve mechanisms. In this case, the suction device may further include a first eccentric cam, a motor, and a second power transmission mechanism. The first eccentric cam is coupled to the plurality of valve mechanisms and rotates to selectively open one of the plurality of valve mechanisms. The second power transmission mechanism is coupled to the motor and includes a planet gear. The planet gear moves in one direction to provide driving force from the motor to the first eccentric cam when the motor rotates in an normal direction, while moving in an other direction to provided driving force from the motor to the suction pump when the motor rotates an in reverse direction.

[0028] Alternatively, the cleaning device includes a plurality of the first vents and a plurality of the second vents, and the suction device includes a plurality of suction pumps, a plurality of valve mechanisms arranged to selectively connect one of the plurality of first vents and the plurality of second vents with the plurality of suction pumps, and a source of power that generates driving force for the plurality of valve mechanisms and one of the plurality of suction pumps.

[0029] Optionally, the first power transmission mechanism further includes a motor and a third power transmission mechanism coupled to the motor. The third power transmission mechanism includes a planet gear which moves in one direction to provide driving force from the motor to a suction pump when the motor rotates in an normal direction, and moves in an other direction to provided driving force from the motor to the first power transmission mechanism when the motor rotates in an reverse direction.

[0030] Optionally or alternatively, the first power transmission mechanism includes a plane gear and an eccentric cam. The first power transmission mechanism provides driving force from the first driving device to the first and second moving mechanisms when the eccentric cam is rotated to first and second operation positions, respectively. When the eccentric cam is at the first operation position, the cap member moves toward and away from the printhead as the first driving device rotates in one direction and an other direction, respectively. Optionally, when the eccentric cam is at the second operation position, the cleaning unit is moved forward and backwards as the first driving device rotates in one direction and an other direction, respectively.

[0031] Optionally, the cleaning device includes a base plate and a guide shaft fixed to the base plate. The guide shaft slidably supports the cleaning unit. In this case, the first power transmission mechanism includes a rack gear fixed to the cleaning unit, and a pinion gear rotatably supported by the base plate. The pinion gear is engaged with the rack gear and rotatably driven by the driving force from the first driving device to move the cleaning unit along the guide shaft via the rack gear.

[0032] According to another aspect of the invention, a cleaning device for cleaning a printhead of an ink-jet printer is provided that includes a cleaning blade, a cleaning blade reciprocating system, a cap member, a cap member moving system, and a first driving force supplying system. The cleaning blade reciprocating system reciprocates the cleaning blade near the printhead so that the cleaning blade wipes an ink ejecting surface of the printhead. The cap member is formed to cover at least a part of the ink ejecting surface and receive waste ink discharged from the printhead. The cap member is moved by the cap member moving system toward and away from the printhead. The cap member comes into close contact with the ink ejecting surface when moved toward to the printhead. The first driving force supplying system is selectively connected to one of the cleaning blade reciprocating system and the cap member moving system to supply driving force thereto. Since the cleaning blade reciprocating system and the cap member moving system are provided with the driving force from a common driving force supplying system, the size of the cleaning device arranged as above can be reduced.

[0033] Optionally, the first driving force supplying system includes a first arm member arranged to swing between the cleaning blade reciprocating system and the cap member moving system, a first planet gear rotatably supported by the first arm member, and a first motor coupled to the first planet gear to rotatably drive the first planet gear. The first planet gear is coupled to the cleaning blade reciprocating system when the first arm member is moved toward the cleaning blade reciprocating system, and to the cap member moving system when the first arm member is moved toward the cap member moving system.

[0034] Further optionally, the cleaning device includes a first arm driving mechanism coupled to the first arm member to swing the first arm member between the cleaning blade reciprocating system and the cap member moving system, a cap vent provided to the cap member to discharge the waste ink received in the cap member, a suction pump connected to the cap vent to vacuum the waste Ink from the cap member, a second driving force supplying system selectively connected to one of the first arm driving mechanism and the suction pump to supply driving force thereto.

[0035] Further optionally, the second driving force supplying system includes a second arm member arranged to swing between the first arm driving mechanism and the suction pump, a second planet gear rotatably supported by the second arm member, and a second motor coupled to the second planet gear to rotatably drive the second planet gear. The second planet gear is coupled to the first arm driving mechanism when the second arm member is moved toward the first swinging mechanism, and to the suction pump when the first arm member is moved toward the first arm member.

[0036] In the above case, the second driving force supplying system may include includes a motor gear fixed to a spindle shaft of the second motor to rotate integrally with the spindle shaft. The motor gear is further engaged with the second planet gear. The second arm member is pivotably coupled to the spindle shaft of the second motor gear so as to swing thereabout.

[0037] Optionally, the cleaning device further includes, an ink absorber arranged to remove ink adhered to the cleaning blade, an absorber vent arranged adjacent to the ink absorber to discharge waste ink from the ink absorber through the absorber vent, a first flow channel arranged between the cap vent and the suction pump, a second flow channel arranged between the absorber vent and the suction pump, and a flow channel selecting system provided to the first and second flow channels to selectively open one of the first and second flow channels.

[0038] In the above case, the flow channel selecting system may include a first valve mechanism provided to the first flow channel, a second valve mechanism provided to the second flow channel, and a valve controlling mechanism coupled to the first and the second valve mechanism to selectively open one of the first and second valve mechanism.

[0039] In the above case, the cleaning device may further include an another cap vent provided to the cap member to discharge waste ink from the cap member therethrough, an another absorber vent arranged adjacent to the ink absorber to discharge waste in from the ink absorber therethrough, an another suction pump connected to both of the another cap vent and the another absorber vent to vacuum the waste ink from the cap member and the ink absorber, respectively, and a third driving force supplying system selectively connected to one of the valve controlling mechanism and the another suction pump to supply driving force thereto.

[0040] Optionally, the third driving force supplying system includes, a third arm member arranged to swing between the valve controlling mechanism and the another suction pump, a third planet gear rotatably supported by the third arm member, and a third motor coupled to the third planet gear to rotatably drive the third planet gear. In this case, the third planet gear is coupled to the valve controlling mechanism when the third arm member is moved toward the valve controlling mechanism, and to the another suction pump when the first arm member is moved toward the another suction pump.

[0041] Optionally, the third driving force supplying system includes an another motor gear fixed to a spindle shaft of the third motor to rotate integrally therewith, and the another motor gear being engaged with the third planet gear. In this case, the third arm member is pivotably coupled to the spindle shaft of the third motor gear so as to swing thereabout.

[0042] FIG. 1 is a perspective view of an ink-jet printer to which a cleaning device according to an embodiment of the invention is applied;

[0043] FIG. 2 is a perspective view of the cleaning device according to the embodiment of the invention;

[0044] FIG. 3 Is a top view of the wiping unit and the capping unit of the cleaning device shown in FIG. 2;

[0045] FIG. 4 illustrates the operation of the wiping unit and the capping unit of the cleaning device shown in FIG. 2;

[0046] FIG. 5 shows a part of the right side of the cleaning device shown in FIG. 2;

[0047] FIG. 6A schematically Illustrates a waste ink discharging channel system of the cleaning device and a valve unit for controlling the flow thereof;

[0048] FIG. 6B is a top view of a first valve mechanism shown in FIG. 6A;

[0049] FIGS. 7A through 7B schematically illustrate an exemplary cleaning process performed by the cleaning device according to the embodiment of the invention;

[0050] FIG. 8 is a timing chart of the general operation of the cleaning device according to the embodiment of the invention;

[0051] FIGS. 9A through 9C illustrate a variation of the cleaning process performed by the cleaning device according to the embodiment of the invention.

[0052] FIG. 10 is a timing chart of the operation of the cleaning device performing the variation of the cleaning process shown in FIGS. 9A through 9C;

[0053] FIGS. 11A through 11C illustrate another variation of the cleaning process performed by the cleaning device according to the embodiment of the invention; and

[0054] FIG. 12 is a timing chart of the operation of the cleaning device performing the another variation of the cleaning process shown in FIGS. 11A through 11C.

[0055] Hereinafter, an embodiment of the invention will be described with reference to the accompanying drawings.

[0056] Initially, a general configuration of an ink-jet printer 1 to which a cleaning device 6 according to the embodiment of the invention is applied will be described with reference to FIG. 1.

[0057] FIG. 1 is a perspective view of the ink-jet printer 1. The ink-jet printer 1 is for commercial use and utilized for printing on a cloth and/or clothes such as T-shirts, for example. Note that the front, rear, right and left sides of the ink-jet printer 1 are respectively defined as shown in FIG. 1.

[0058] Main portions of the ink-jet printer 1 are mounted to a frame 20. The main portions of the ink-jet printer 1 include a printing unit, a recovering unit that cleans a printhead 5 to prevent or remove clogging, and a platen unit to which the recording medium or the cloth Is to be set.

[0059] The printing unit includes the printhead 5, a carriage 4 for holding ink cartridges (not shown), one or more guide shafts 2 along which the carriage 4 reciprocally slides to right and left (i.e., in a main scanning direction), and a driving belt 3 that is coupled with the carriage 4 to transmit a driving force thereto for moving back and force.

[0060] The recovering unit includes the cleaning device 6, a flushing unit 7, and a waste ink pooling device 8. The cleaning device 6 recovers or carries out cleaning of the printhead 5 at a predetermined interval when the printhead 5 is placed at an initial position (at the right side of the frame 20). The flushing unit 7 receives waste ink discharged from the printhead 5 that is moved to the left side of the frame 20 during the printing process to perform preparative discharge or flushing. The waste ink discharged from the cleaning device 6 or the flushing unit 7 flows into the waste ink pooling device 8, which is set into a placement opening 10, through an opening 9.

[0061] The platen unit 11 includes a guide plate 15 that guides the recording medium such as a T-shirts, a platen 12 on which the printing area of the recording medium is to be placed, and a frame 14 that fixes the recording medium to the platen 12.

[0062] Next, the general operation of the ink-jet printer 1 will be described.

[0063] When a user depresses a platen operation switch (not shown), the platen 12, which has been at a print position in the ink-jet printer 1, slides out from the inkjet printer 1 to be located at a recording medium setting position as shown in FIG. 1. Then, the user opens the platen unit 1 by lifting up the frame 14, and place the recording medium on the platen 12. Then, the user moves down the frame 14 to close the platen unit 11 and thereby fix the recording medium to the platen unit 11. Next, a print starting switch (not shown) is depressed to slide back the platen unit 11 to the print position.

[0064] After the platen unit 11 has returned to the print position, the printing operation starts. That is, the driving belt 3 drives the carriage 4, which holds the printhead 5, back and forth in the main scanning direction while the printhead 5 discharges ink droplets onto the recording medium. After the carriage 4 has reciprocated once in the main scanning direction, the platen unit 11 is moved in a direction perpendicular to the main scanning direction, or auxiliary scanning direction, for one step of a predetermined length, and then the next line in the main scanning direction is printed. By repeating the operation described above, a predetermined pattern is printed on the recording medium.

[0065] The printhead 5 is provided with a plurality of nozzle groups (four groups in the present embodiment), each corresponding to different color ink. The ink cartridges containing different color inks are held by the carriage 4. During the printing operation, the ink cartridges supply color inks through separate ink supplying conduits to respective nozzle groups.

[0066] The waste ink that is discharged from the printhead 5 or sucked out from the printhead 5 at the cleaning device 6 in order to purge the printhead 5, and also the waste ink that is flushed from the printhead 5 at the flushing unit 7 flow through respective waste ink discharging conduits (not shown) to a tube (not shown) located above the opening 9 of the waste ink pooling device 8 inserted into the ink-jet printer 1. The waste ink drops down from the tube into the waste ink pooling device 8 through the opening 9

[0067] Next, the configuration of the cleaning device 6 according to the embodiment of the invention will be described.

[0068] FIG. 2 is a perspective view of the cleaning device 6 according to the embodiment of the invention. Note that the right and left hand sides in FIG. 2 corresponds to the rear and front sides of the cleaning device 6, respectively, and the near and far sides in FIG. 2 to the right and left sides of the cleaning device 6, respectively.

[0069] The cleaning device 6 shown in FIG. 2 includes a wiping unit and a capping unit, as well as a main driving unit and a main driving force transmitting unit for actuating, the wiping unit and the capping unit. Further, the cleaning device 6 includes, Y (yellow) ink pump driving unit, capping switching unit, C (cyan) ink pump driving unit, valve switching unit, and a base plate 32 to which the above-mentioned units are mounted.

[0070] Hereinafter, the configuration of the wiping unit and the capping unit will be described in detail with reference to FIGS. 2 through 4. FIG. 3 is a top view of the wiping unit and the capping unit of the cleaning device 6 shown in FIG. 2, and FIG. 4 illustrates the operation of the wiping unit and the capping unit of the cleaning device 6 shown in FIG. 2.

[0071] As shown in FIG. 2, the wiping unit has a cleaning blade 21, a blade supporting plate 22, a pair of blade actuating plates 24, a carriage plate 25, a carriage 26, a pair of brackets 27, a pair of guide shafts 28 (only one is shown), rack gears 29, a first absorber 31, a second absorber 30, and an absorber supporting plate 35 (see FIG. 4).

[0072] As shown in FIG. 4, the capping unit includes a plurality of cap members 23 (see also FIG. 2), a cap supporting member 55, a cap supporting rod 54, a cam follower 56, an eccentric cam 53, and a cam rotating gear 52.

[0073] As can be seen in FIG. 2, the carriage 26 Is slidably mounted to the guide shafts 28 (only one is shown) so as to be movable back and forth (in right and left direction in FIG. 2). The guide shafts 28 are arranged in parallel with an ink ejecting surface 5a of the printhead 5. The carriage plate 25 is fixed on the carriage 26 so as to extend over the base plate 32 and being substantially parallel to the ink ejecting surface Sa of the printhead 5.

[0074] Each blade actuating plate 24 is mounted on the upper surface of the carriage plate 25 pivotably for a predetermined angle. The brackets 27 are also fixed on the carriage plate 25. Each bracket 27 is formed in an L like shape, while the blade supporting plate 22 is formed in a U like shape. The blade supporting plate 22 is pivotably coupled to the upright portion of the L shaped brackets 27 by means of supporting pins 27b so as to be able to swing for a predetermined angle about an axis parallel to the ink ejecting surface 5a of the printhead 5 (see FIG. 4).

[0075] The cleaning blade 21 is attached to a side surface of the blade supporting plate 22. The cleaning blade 21 is made from a flexible material, such as rubber, and wipes the ink ejecting surface 5a of the printhead 5 to clean unwanted ink thereon.

[0076] As shown in FIG. 3, a coil spring 27a is provided between the blade supporting plate 22 and the bracket 27 to bias the blade supporting plate 22. One end of the coil spring 27a Is connected to the blade supporting plate 22, while the other end thereof is fixed to a side of the upright portion of the bracket 27. The coil spring 27a biases the blade supporting plate 22 (in a counter clockwise direction in FIG. 2) so that the side surface of the blade supporting plate 22 inclines against the ink ejecting surface 5a of the printhead 5.

[0077] One end of the blade actuating plate 24 is mounted on the carriage plate 25 by means of a screw 25b such that the blade actuating plate 24 can swing about the screw 25b for a predetermined angle. The blade actuating plate 24 has a bent portion 24a that extends downwardly through an opening 25a formed to the carriage plate 25. The bent portion 24a moves within the opening 25a between two opposing sides thereof as the blade actuating plate 24 swings right and left. Thus, the swinging angle of the blade actuating plate 24 is restricted by the opening 25a.

[0078] When the blade actuating plate 24 swings in left hand side direction in FIG. 3 until the bent portion 24a abuts against one side of the opening 25a, the blade actuating plate 24 slides under the blade supporting plate 22, abuts against the under surface of the blade supporting plate 22 to move it against the biasing force of the coil spring 27a to an upright position, or upright attitude, at where the cleaning blade 21 attached to the blade supporting plate 22 becomes substantially perpendicular to the ink ejecting surface 5a of the printhead 5.

[0079] On the contrary, if the blade actuating plate 24 swings in the opposite direction, right hand side direction in FIG. 3, until the bent portion 24a abuts against the other side of the opening 25a, the blade actuating plate 24 slides away from the blade supporting plate 22 to allow the coil spring 27a biasing back the blade supporting plate 22 to an inclined position (inclined attitude) at where the cleaning blade 21 is inclined against the ink ejecting surface 5a.

[0080] It should be noted that, in FIG. 3, the wiping unit represented by solid lines is located at an initial position (standby position, wiping end position), which is at the left hand side in FIG. 3, while the wiping unit represented in broken lines is located at a wiping start position, which is at the right hand side in FIG. 3. Details on the initial position and the wiping start position will be described later.

[0081] Referring back to FIG. 2, each rack gear 29 is fixed to the side of the carriage 26. Each rack gear 29 is engaged with a pinion gear 45. Thus, the carriage 26 moves back and forth horizontally (in the right and left direction in FIG. 2) along the guide shafts 28, which are mounted to the base plates 32, as the pinion gear 45 rotates in counterclockwise and clockwise directions. Note that only one of the guide shafts 28 is shown in FIGS. 2 through 4 although another one is provided at the left side of the cleaning device 6.

[0082] As shown in FIG. 4, the first absorber 31 is supported by a first absorber supporting member 37 so as to incline for a predetermined angle against a direction perpendicular to the ink ejecting surface 5a (against the vertical direction in the present embodiment). The inclination of the first absorber supporting member 37 is adjusted such that the entire side surface of the cleaning blade 21 comes into contact with the first absorber 31 when the wiping unit is located at the initial position and the cleaning blade 21 is disposed at the inclined position. The first absorber 31 removes the ink adhered to the side surface of the cleaning blade 21 so that the cleaning blade 21 can keep high wiping ability.

[0083] A plurality of absorber vents 37a are provided to the first absorber supporting member 37 adjacent to the lower portion of the first absorber 31, although only one is shown in FIG. 4, for sucking out ink from the first absorber 31. The number of the absorber vents 37a is equal to the number of the nozzle groups or the number of the color ink to be utilized, that is, four In the present embodiment. The absorber vents 37a are arranged in one line in the direction substantially parallel to the ink ejecting surface 5a of the printhead and substantially perpendicular to the direction along which the wiping unit travels. Further, the absorber vents 37a are arranged at substantially the same height as the cap members 23 located at the lower most position thereof.

[0084] The second absorber 30 is supported by a second absorber supporting member 36 at a location where it will be rubbed with the tip portion of the cleaning blade 21 moved horizontally below the second absorber 30 while being kept at the upright position. The second absorber 30 removes the ink adhered to the tip portion of the cleaning blade 21 so that the cleaning blade 21 can effectively wipe the ink ejecting surface 5a.

[0085] Note that the first and second absorber supporting members 37 and 36 are fixed to the absorber supporting plate 35 by means of screws.

[0086] The cleaning device 6 is further provided with four cap members 23 (see also FIG. 2), each corresponding to one of the C (cyan) ink, M (magenta) ink. Y (yellow) ink, and K (black) ink. Each of the cap members 23 is arranged to cover an area of the ink ejecting surface 5a of the printhead 5 that includes the nozzle group associated with the corresponding color ink.

[0087] Each cap member 23 is provided with a cap vent 23a formed at the bottom thereof (see FIG. 3). The ink sucked out from the printhead 5 and received in the cap member 23 will be discharged through the cap vent 23a.

[0088] As shown in FIG. 4, the cap members 23 are supported by the cap supporting member 55 which is fixed to the top end of the cap supporting rod 54. The cam follower 56 is rotatably provided at the bottom end of the cap supporting rod 54. The cam follower 56 follows the periphery of the eccentric cam 53, which is rotated by the cam rotating gear 52.

[0089] The cam rotating gear 52 is engaged with the transmission gear 51 at any time. The transmission gear 51 Is concentrically coupled with the cap gear 43 to rotate integrally therewith. If the cap gear 43 is engaged with and driven by a main driving planet gear 44, the driving force is transmitted to the eccentric cam 53. As a result, the eccentric cam 53 rotates and the cap members 23 move up and down.

[0090] Next, the configuration of main driving unit and the main driving force transmitting unit will be described with reference to FIGS. 2 and 4.

[0091] The main driving unit and the main driving force transmitting unit includes a main driving motor 40, a main driving motor gear 41, a transmission gear 42, the cap gear 43, the main driving planet gear 44, the pinion gear 45, and a main drive switching arm 46.

[0092] The main driving motor 40 is the source of power of the main driving unit. The main driving motor gear 41 is attached to the spindle shaft of the main driving motor gear 41 and engaged with the transmission gear 42 all the time. Further, the transmission gear 42 is engaged with the main driving planet gear 44 all the time. Thus, both the transmission gear 42 and the main driving planet gear 44 rotate in accordance with the rotation of the main driving motor 40.

[0093] The main drive switching arm 46 is swingably coupled with the shaft of the transmission gear 42 at one end thereof. The main drive switching arm 46 rotatably supports the main driving planet gear 44 at substantially the center thereof. Further, the main drive switching arm 46 is provided with a U shaped groove formed at the other end thereof. The U shaped groove receives the eccentric cam 50 therein. Thus, the main drive switching arm swings up and down as shown by broken lines in FIG. 4 as the eccentric cam 50 rotates.

[0094] When the main drive switching arm 46 is lifted up by the eccentric cam 50, the main driving planet gear 44 engages with the pinion gear 45. In this case, the driving force generated by the main driving motor 40 is transmitted to the rack gear 29 via the pinion gear 45 to move the carriage 26 horizontally, or between the initial position and the wiping start position. It should be noted that the movement and position of the wiping unit can be precisely controlled since the driving force is transmitted by a gear mechanism as above.

[0095] If the main driving switch arm 46 is moved downwards by the eccentric cam 50, the main driving planet gear 44 engages with the cap gear 43. In this case, the driving force is transmitted from the main driving motor 40 to the eccentric cam 53 through the cap gear 43, transmission gear 51 and the cam rotating gear 52. The eccentric cam 53 rotates and thereby moves the cap members 23 up and down.

[0096] It should be noted that the main driving unit arranged as above allows downsizing of the cleaning device 6 since it requires only one motor (i.e., the main driving motor 40) for reciprocating the carriage 26 (and the cleaning blade 21) and raising/lowering the cap members 23. It should be also noted that since only one of the carriage 26 and the cap members 23 can be driven in the arrangement above, malfunctions such as simultaneously operation of the carriage 26 and the cap members 23 do not occur. Further, since the switching between the reciprocation of the carriage and the movement the cap members 23 is achieved by rotating the eccentric cam 50, the structure of the cleaning device 6 Is simple and hence the cleaning device 6 operates with high reliably.

[0097] Next, the configurations of the Y ink pump driving unit and the capping switching unit will be described with reference to FIGS. 2, 4 and 5.

[0098] As shown in FIG. 5, the Y ink pump driving unit and the capping switching unit include a Y ink motor 69, a Y ink motor gear 66, a Y ink switching arm 67, a Y ink planet gear 65, a Y ink pump gear 68, a Y ink belt 62, a Y ink transmission gear 64, a Y ink transmission pulley 63, a main drive switching pulley 60 (see FIG. 2), a main driving switching pulley sensor 61 (see FIG. 2), and a Y ink pump (not shown).

[0099] Referring to FIG. 5, the Y ink motor 69 is the source of power of the Y ink pump driving unit and the capping switching unit. The Y ink motor gear 66 is attached to the spindle shaft of the Y ink motor 69. The Y ink motor gear 66 is engaged with the Y ink planet gear 65 all the time. The Y ink planet gear 65 is rotatably supported by the Y ink switching arm 67. The Y ink switching arm 67 is pivotably mounted to the spindle shaft of the Y ink motor 69. Thus, the Y ink switching arm 67 swings in both clockwise and counter clockwise directions if the Y ink motor 69 is rotated in normal and reverse directions, respectively, and selectively engages with one of the Y ink pump gear 68 and Y Ink transmission gear 64. If the Y ink motor 69 rotates in clockwise direction in FIG. 5, the Y ink planet gear 65 engages with the Y ink pump gear 68 and actuates the Y ink pump (not shown). If the Y ink motor 69 rotates in counterclockwise direction in FIG. 5, the Y ink planet gear 65 engages with the Y ink transmission gear 64.

[0100] The Y ink transmission pulley 63 is concentrically coupled with the Y ink transmission gear 64, and a Y ink belt 62 is wrapped around the Y ink transmission pulley 63. The Y ink belt 62 is also wrapped around the main drive switching pulley 60 (see FIG. 2). Accordingly, if the Y ink transmission gear 64 is rotated, the driving force is transmitted to the main drive switching pulley 60 via the Y ink transmission pulley 63 and the Y ink belt 62. As a result, the main drive switching pulley 60 rotates and the eccentric cam 50 (see FIG. 4) coupled thereto also rotates. The rotation of the eccentric cam 50 causes the main drive switching arm 46 to move up and down.

[0101] The rotational position of the main drive switching pulley 60, and hence the rotational position of the eccentric cam 50, is detected by the main drive switching pulley sensor 61. The position of the main drive switching arm 46 can be controlled based on the output of the main drive switching pulley sensor 61.

[0102] It should be noted that Y ink pump driving unit and the capping switching unit arranged as above require only one motor (i.e., the Y ink motor 69) for driving the Y ink pump and the main drive switching arm 46. Thus, the cleaning device 6 can be made compact. Further, the selection of the one to be driven (i.e., the Y ink pump or the main drive switching arm 46) can be performed only by changing the direction of rotation of the Y ink motor 69. Therefore, it is not necessary to provide the cleaning device with complex controlling circuitry and/or mechanism.

[0103] Next, the configurations of the C ink pump driving unit and the valve switching unit will be described with reference to FIGS. 2 and 5.

[0104] The C ink pump driving unit and the valve switching unit include a C ink motor 89, a C ink motor gear 86, a C ink switching arm 87, a C ink planet gear 85, a C ink valve 121 (see FIG. 6B), a C ink pump gear 88, a valve driving belt 82, a C ink transmission gear 84, a C ink transmission pulley 83, a valve switching pulley 80, a valve switching pulley sensor 81, and a C ink pump which is not shown.

[0105] The C ink motor 89 is the source of power of the C ink pump driving unit and the valve switching unit. The spindle shaft of the C ink motor 89 is provided with the C ink motor gear 86 which is in engagement with the C ink planet gear 85 all the time. The C ink planet gear 85 is rotatably supported by the C ink switching arm 87. The C ink switching arm 87 is pivotably mounted to the spindle shaft of the C ink motor 89. The C ink switching arm 87 swings in both clockwise and counterclockwise directions as the C ink motor 89 rotates in normal and reverse directions, respectively, and selectively engages with one of the C ink pump gear 88 and C ink transmission gear 84. If the C ink motor 89 rotates in the clockwise direction in FIG. 5, the C ink planet gear 85 engages with the C ink pump gear 88 and actuates the C ink pump (not shown). If the C ink motor 89 rotates in the counterclockwise direction in FIG. 5, the C ink planet gear 85 engages with the C Ink transmission gear 84.

[0106] The C ink transmission pulley 83 is concentrically coupled with the C ink transmission gear 84, and the valve driving belt 82 is wrapped around the C ink transmission pulley 83. The valve driving belt 82 is also wrapped around the valve switching pulley 80 (see FIG. 2). Accordingly, if the C ink transmission gear 84 is rotated, the driving force is transmitted to the valve switching pulley 80 via the C ink transmission pulley 83 and the valve driving belt 82. As a result, the valve switching pulley 80 rotates and an eccentric cam 104 (see FIG. 6B) coupled thereto also rotates. As will be described later, first, second and third valves mechanisms (101, 102, 103) are selectively opened and closed by the rotating eccentric cam 104.

[0107] The rotational position of the valve switching pulley 80, and hence the rotational position of the eccentric cam 104, is detected by the valve switching pulley sensor 81. The rotational position of the eccentric cam 104, and hence the open/close of the first through third valves (101, 102, 103) can be controlled based on the output of the valve switching pulley sensor 81.

[0108] It should be noted that a M (magenta) ink motor and a M ink pump driven therewith, and a K (black) ink motor and a K ink pump driven therewith are also mounted to the base plate 32, but not shown in the drawings.

[0109] It should be noted that C ink pump driving unit and the valve switching unit arranged as above facilitate the downsizing of the cleaning device 6 since the arrangement above requires only one motor (i.e., the C ink motor 89) for driving the C ink pump and the first through third valve mechanisms (101, 102, 103). Further, since the selection of the one to be driven (i.e., the Y ink pump or the main drive switching arm 46) is achieved only by changing the direction of rotation of the C ink motor 89, it is not necessary to provide the cleaning device 6 with complex controlling circuitry and/or mechanism.

[0110] Next, the general configuration of a valve unit 100, which is connected with the wiping unit and the capping unit via tubes, or flow channel, will be described with reference to FIGS. 6A and 6B.

[0111] FIG. 6A schematically shows a waste ink discharging channel system of the cleaning device 6 and the valve unit 100 for controlling the flow thereof.

[0112] The waste ink discharging channel system includes four sets of first, second and third flow channels and four conventional suction pumps 130 (only one set of the first through third flow channels and the pump 130 is shown). Each of the first flow channel is formed between one of the cap vent 23a and one of the pump 130, while each of the third flow channel is formed between one of the absorber vent 37a and one of the pump 130. Each second flow channel is connected to one of the cap vent at one end thereof. The other end of each second flow channel is left open to the atmosphere.

[0113] The valve unit 100 opens/closes the first through third flow channels and thereby determines through which flow channel the waste ink should flow. The valve unit 100 includes the first valve mechanism 101 for simultaneously opening/closing the four first flow channels, the second valve mechanism 102 for simultaneously opening/closing the four second flow channels, and the third valve mechanism 103 for simultaneously opening/closing the four third flow channels. The valve unit 100 further includes the eccentric cam 104 for driving the first through third valve mechanisms (101, 102, 103), and a housing 105 for accommodating the above mentioned members.

[0114] The first, second and third flow channels are formed by first through fifth flexible tubes (111, 112, 113, 114, 116), and first and second joints (115, 117). The first, second and third tubes 111, 112, and 113 are passed through the first, second and third valve mechanism (101, 102, 103), respectively.

[0115] The third tube 113 is connected with the absorber vent 37a at one end thereof. The fourth tube 114 is connected with the cap vent 23a, and the fifth tube 116 is connected with the pump 130. The fourth tube 114 is also connected with both the first and second tubes 111 and 112 by the first joint 115 that is formed in a Y shape, and the fifth tube 116 is connected with both the first and third tubes 111 and 113 via the second joint 117 that is also formed in Y shape. The end of the second tube 112 that is not connected to the first joint 115 is left open to the atmosphere. The first, fourth, and fifth tubes (111, 114, 116) define the first flow channel. The second and fourth tubes (112, 114) define the second flow channel. Further, the third and fifth tubes (113, 116) define the third flow channel.

[0116] Note that a sixth tube 131 is connected to the discharging opening of the pump 130. The waste ink sucked into the pump 130 is discharged therefrom through the sixth tube 131 into the waste ink pooling device 8 (see FIG. 1).

[0117] FIG. 6B is a top view of the first valve mechanism 101 shown in FIG. 6A. As shown in FIG. 6B, the first valve mechanism 101 includes four valves, i.e., a Y ink valve 120, a C ink valve 121, an M ink valve 122, and a K ink valve 123. Each valve corresponds to different color ink, or respective cap vents 23a. Each valve has the same structure and actuate simultaneously. Further, the second and third valve mechanisms 102 and 103 have the same structure as the first valve mechanism 101. Thus, the structure of only one valve of the first valve mechanism 101 will be described hereinafter and the description of other valves and other valve mechanisms (102, 103) will be omitted.

[0118] As shown in FIG. 6A, the first valve mechanism 101 includes a valve block 106, a valve piston 107, a metal shaft 108, and a compression spring 109.

[0119] The valve block 106 is provided with a bore into which the valve piston 107 is slidably received. A circular plate having a larger diameter than the valve piston 107 is attached to the bottom of the valve piston 107 to serve as a cam follower 107c that follows the periphery of the eccentric cam 104. The compression spring 109 is located between the valve block 106 and the cam follower 107c. The compression spring 109 biases the cam follower 107c toward the eccentric cam 104.

[0120] A first rectangular bore 107b is formed to the valve piston 107 to allow the first tube 111, which is made from vinyl resin, passing through the valve piston 107. A second rectangular bore 107a is further formed to the valve piston 107 in a direction perpendicular to the first rectangular bore 107b. The metal shaft 108 is passed through the second bore 107a. Thus, the metal shaft 108 is located adjacent to and perpendicularly to the first tube 111. The metal shaft 108 has a longer dimension than the diameter of the bore formed to the valve block 106. Thus, the metal shaft 108 does not passes through the bore of the valve block 106 even if it is pressed down by the valve piston 107.

[0121] The valve piston 107 moves up and down as the eccentric cam 104 rotates. When the valve piston 107 is not moved up by the eccentric cam 104 and is located at its lower position (as shown in the second and third valves mechanism 102 and 103 of FIG. 6A), the metal shaft 108 presses and thereby closes the first tube 111. On the contrary, when the eccentric cam 104 lifts up the valve piston 107 against the biasing force of the compression spring 109, the metal shaft 108 releases the first tube 111 Thus, the first tube 111 opens.

[0122] Next, the cleaning process performed by the cleaning device 6 according to the embodiment of the invention will be described with reference to FIGS. 7A through 7C. The cleaning process of the cleaning, device 6 includes a purging operation (see FIG. 7A) and a wiping operation (see FIGS. 7B and 7C), which will be carried out after the purging operation.

[0123] In the purging operation shown in FIG. 7A, the cap members 23 are lifted up to cover the ink ejecting surface 5a of the printhead 5, or cap respective nozzle groups of the printhead 5, as indicated in broken lines in FIG. 7A.

[0124] Then, purging of the nozzles is carried out. That is, the C ink motor 89 (see FIG. 5) is driven in reverse direction so that the C ink planet gear 85 engages with the C ink transmission gear 84 and the driving force generated by the C ink motor 89 is transmitted to the eccentric cam 104 via the switching pulleys 80, 83 and the driving belt 82 (see also FIGS. 2 and 6A). The eccentric cam 104 is rotated so as to move up the valve piston 107 of the first valve mechanism 101 against the biasing force of the compression spring 109. As a result, the tube pressing shaft 108 stops pressing the first tube 111, and the cap vent 23a comes in fluid communication with the pump 130. Then, the pump 130 is actuated to suck out the ink remaining in the nozzles of the printhead 5 and receive it with the cap member 23.

[0125] Then, the pump 130 is stopped for a while to allow the ink received in the cap member 23 to flow toward the bottom of the cap member 23.

[0126] Then, the C ink motor 89 is driven in the reverse direction again to rotate the eccentric cam 104 to move up the valve piston 107 of the second valve mechanism 102 and thereby open the second tube 112. As a result, the cap vent 23a comes in communication with the atmosphere through the second fluid channel. In the meantime, the valve piston of the first valve mechanism 101 is moved down and the first tube 111 is closed.

[0127] Then, the cap members 23 is slightly moved down so that a gap is formed between the cap members 23 and the ink ejecting surface 5a of the printhead 5. Then, the C ink motor 89 is driven in the reverse direction again so that the valve piston 107 of the first valve mechanism 101 is moved up again. In other words, the first tube 111 is opened while the second tube 112 Is closed. Then, the pump 130 is actuated to suck the waste ink within the cap member 23 through the cap vent 23a. After a predetermined time, the pump 130 is stopped, or the suction is stopped, and the cap members 23 are moved down to the initial position indicated by solid lines in FIG. 7A.

[0128] After the purging operation described above, the wiping operation illustrated in FIGS. 7B and 7c is carried out.

[0129] As shown In FIG. 7B in broken lines, the wiping unit is initially located, or waiting, at the initial position (1), which is at the left hand side in FIG. 7B, with the cleaning blade 21 being inclined against the ink ejecting surface 5a of the printhead 5 for a predetermine angle. In this state, the side surface of the cleaning blade 21 is in contact with the first absorber 31.

[0130] After the purging operation is over, the wiping unit is moved from the initial position (1) to the wiping start position (3) indicated by solid lines in FIG. 7B. During the movement, the wiping unit passes by the printhead 5 as shown in broken lines at position (2), however, the tip portion of the cleaning blade 21 does not come into contact with the ink ejecting surface 5a of the printhead 5 since the cleaning blade 21 is inclined and the tip portion thereof is kept at a lower position than the ink ejecting surface 5a.

[0131] As the wiping unit approaches the wiping start position (3), the bent portion 24a of the blade actuating plate 24 abuts against a first protrusion 33 extending upwardly from the top of the base plate 32. The bent portion 24a is urged by the first protrusion 33 to move from the rear side to the front side of the opening 25a formed to the carriage plate 25 (from right hand side to left hand side in FIG. 7B). Thus, the blade actuating plate 24 moves toward the blade supporting plate 22 and abuts against an abutting portion 22a formed at a lower end of the blade supporting plate 22. As a result, the blade supporting plate 22 swings about the supporting pin 27b in a clockwise direction in FIG. 7B. When the bent portion 24a arrives at the front side (the left hand side in FIG. 7B) of the opening 25a, the front side of the blade supporting plate 22, and hence the cleaning blade 21, is located at the upright position thereof (i.e. the cleaning blade 21 is supported perpendicularly to the ink ejecting surface 5a of the printhead 5).

[0132] The wiping unit is kept at the wiping start position for a predetermined period of time.

[0133] Then, as shown in FIG. 7C, the wiping unit moves from the wiping start position (3) toward the initial position (1) with the cleaning blade 21 kept at the upright position thereof. When the wiping unit moves below the printhead 5, as shown in broken lines at position (4), the tip portion of the cleaning blade 21 comes into contact with the ink ejecting surface 5a thereof and is warped. The warped tip portion of the cleaning blade 21 is rubbed against the ink ejecting surface 5a and thereby wipes the ink off the ink ejecting surface 5a.

[0134] The wiping unit is once stopped just before the warped tip portion of the cleaning blade 21 comes off from the ink ejecting surface 5a, and is moved again after a predetermined period of time. By operating the wiping unit as above, scattering of the ink caused by strong springing back of the warped tip portion of the cleaning blade 21 can be prevented.

[0135] The wiping unit is further moved toward the initial position (1). Before the wiping unit arrives at the initial-position, the tip portion of the cleaning blade 21 comes into contact with the under surface of the second absorber 30, which is made from felt, nonwoven cloth or the like (see wiping unit illustrated in broken lines at position (5)). Thus, the tip portion of the cleaning blade 21 Is rubbed against the second absorber 30 for a predetermined time as the wiping unit approaches the initial position (1) and the ink adhered to the tip portion of the cleaning blade 21 is absorbed or wiped off by the second absorber 30.

[0136] As the wiping unit further moves toward the initial position (1), a second protrusion 34 formed to the base plate 32 abuts the bent portion 24a of the blade actuating plate 24 and thereby urges the bent portion 24a from the front side of the opening 25a of the carriage plate 25 to the rear side thereof (from left hand side to right hand side in FIG. 7C). As a result, the blade actuating plate 24, which has been supported the blade supporting plate 22 at the upright position thereof, slides away from the blade supporting plate 22. Thus, the blade supporting plate 22 swings about the supporting pin 27b due to the biasing force of the coil spring 27a, in counterclockwise direction in FIG. 7C, to locate the cleaning blade 21 to the inclined position thereof.

[0137] Finally, the wiping unit arrives at the initial position (1) and the cleaning blade 21 comes into contact with the first absorber 31 at substantially the entire side surface thereof. Thus, the ink adhered to the side surface of the cleaning blade 21 is absorbed by the first absorber 31. Note that the cleaning blade 21 is located above the first absorber 31 so that the ink can be effectively absorbed by the first absorber 31 with the help of gravity.

[0138] It should be noted that moving the cleaning blade 21 between the upright and inclined positions thereof does not requires any additional time to the cleaning process. Thus the entire cleaning process can be carried out in a short time. Further, since the movement of the cleaning blade 21 between the upright and inclined positions is caused by the first and second protrusions 33, 34 located in the vicinity of the wiping start position and the initial position of the wiping unit, respectively, the cleaning blade 21 is reliably moved to the required position as the wiping blade approaches the initial or wiping start position, or before the wiping units changes the traveling direction thereof. Thus, the cleaning blade never passes by the recording head with an unexpected attitude.

[0139] It should be noted that a part of the under surface of the second absorber 30 is in close contact with the top surface of the first absorber 31. Thus, the ink absorbed by the second absorber 30 gradually moves into the first absorber 31 due to permeate and gravity. Note that although the first and second absorber 31 and 30 are separate members in the present embodiment, they may be also integrally connected to each other.

[0140] The ink held in the first absorber 31, and hence the ink in the second absorber 30, is sucked out through the absorber vent 37a located adjacent to the lower end of the first absorber 31. That is, the C ink motor 89 is driven in reverse direction to rotate the eccentric cam 104 (see FIG. 6A) until the valve piston 107 of the third valve mechanism 103 is moved up against the biasing force of the compression spring 109. As a result, the metal shaft 108 of the third valve mechanism 103 stops pressing the third tube 113 and allows the absorber vent 37a to be in fluid communication with the pump 130 via the third fluid channel. Then, the pump 130 is actuated to remove the waste ink from the first absorber 31 (and also from the second absorber 30) through the absorber vent 37a by suction. In this way, the abilities of the first and second absorbers 31, 30 for removing ink form the cleaning blade 21 are maintained irrespective of the times the cleaning process is preformed.

[0141] As shown in FIG. 7C, the side surface of the first absorber 31 is covered with the cleaning blade 21 except near the lower end thereof. In other words, the lower end portion of the first absorber 31 that is adjacent to the absorber vent 37a is not covered with the cleaning blade 21. Thus, when the pump 130 is actuated to vacuum the waste ink through the absorber vent 37a, an air flow is formed that penetrates the first absorber 30 at the lower end portion thereof. Thus, the waste ink that has moved down to the lower end portion of the first absorber 30 due to gravity can be effectively removed.

[0142] Next, the carriage 4 is moved above the flushing unit 7 provided at the left side of the ink-jet printer 1 (see FIG. 1), and the printhead 5 starts the preparative discharge (or flushing) of the ink, that is, ink is discharged into the flushing unit 7. Thereafter, the C ink motor 89 is driven in reverse direction to rotate the eccentric cam 104 until the valve piston 107 of the second valve mechanism 102 is moved up against the biasing force of the compression spring 109. As a result, the metal shaft 108 stops pressing the second tube 112 and allows the cap vent 23a to be in fluid communication with the atmosphere via the second fluid channel.

[0143] Then, the carriage 4 is moved back above the cap members 23 and the cap members 23 cover the ink ejecting surface 5a of the printhead 5 again. Further, the C ink motor is driven again in the reverse direction to move the eccentric cam 104 until the valve piston 107 of the third valve mechanism 103 is moved up to open the third tube 113. Thus, the absorber vent 37a comes in fluid communication with the pump 130 via the third fluid channel.

[0144] Hereinafter, the operation of each of the aforementioned units and the way of changing the unit to be actuated will be described with reference to FIG. 4.

[0145] FIG. 4 shows the wiping unit placed at the initial position thereof and the printhead 5 located above the cap members 23. The cap members are located at the lowermost position thereof. The cap members can be moved up to cap the ink ejecting surface 5a of the printhead 5. Each of the cap members is provided with the cap vent 23a at the bottom thereof for discharging of the waste ink. The cleaning blade 21 of the wiping unit is In contact with the first absorber 31 at the side surface thereof. The top of the first absorber 31 is in close contact with the second absorber 30 that is provided for removing the ink adhered to the tip portion of the cleaning blade 21.

[0146] The main driving motor 40 is fixed to the base plate 32. The driving force generated by the main driving motor 40 is transmitted to the main driving planet gear 44 via the main driving motor gear 41, which is provided to the spindle shaft of the main driving motor 40, and the transmission gear 42.

[0147] If the main drive switching arm 46 is moved upwards, the main driving planet gear 44 engages with and thereby rotates the pinion gear 45. The pinion gear 45, in turn, moves the rack gear 29 and hence the carriage 26. The direction in which the carriage 26 moves depends on whether the main driving motor is driven in the normal or reverse direction thereof.

[0148] On the contrary, if the main drive switching arm 46 is moved downwards, the main driving planet gear 44 engages with the cap gear 43. The driving force generated by the main driving motor 40 is transmitted from the cap gear 43 to the cam rotating gear 52 via the transmission gear 51, which is sharing the rotation axis with the cap gear 43. The eccentric cam 53 is fixed to the rotation axis of the cam rotating gear 52. Thus, eccentric cam 53 integrally rotates with the cam rotating gear 52. As the eccentric cam 53 rotates, the cam follower 56 moves up and down by following the periphery of the eccentric cam 53. As a result, the cap supporting rod 54 coupled to the cam follower 56 at one end thereof, the cap supporting member 55 attached at the other end of the cam supporting rod 54, and the cap members 23 mounted on the cap supporting member 55 move up and down.

[0149] In the present embodiment, the cap members 23 move up to cap the ink ejecting surface 5a when the main driving motor 40 rotates in one direction, and move down or move away from the ink ejecting surface 5a if the main driving motor 40 rotates in the other direction. The current position of the cap members 23 can be determined based on the output of a sensor (not shown) that detects the rotational position of the cam rotating gear 52.

[0150] Next, the mechanism and operation of moving up and down the main drive switching arm 46 will be described with reference to FIGS. 4 and 5.

[0151] As shown in FIG. 5, the Y ink motor 69 is mounted to the base plate 32 at the inner side thereof. The Y ink motor gear 66 is fixed to the spindle shaft of the Y ink motor 69. The Y ink switching arm 67 is pivotably mounted to the spindle shaft of the Y ink motor 69 so as to be swingable right and left. The Y ink planet gear 65 is rotatably supported by the Y ink switching arm 67. The Y ink planet gear 65 is also engaged with the Y ink motor gear 66.

[0152] If the Y ink motor 69 rotates in normal direction, the Y ink switching arm 67 swings in clockwise direction in FIG. 5. As a result, the Y ink planet gear 65 engages with and thereby transmits the driving force generated by the Y ink motor 69 to the Y ink pump gear 68 so that the Y ink pump (not shown) actuates.

[0153] On the contrary, If the Y ink motor 69 rotates in reverse direction, the Y ink switching arm 67 swings in counterclockwise direction and the Y ink planet gear 65 engages with the Y ink transmission gear 64. As a result, the driving force from the Y ink motor 69 is transmitted to the Y ink transmission pulley 63, which shares the rotation axis with the Y in transmission gear 64, the Y ink belt 62, the main drive switching pulley 60 (see FIG. 4), and finally to the eccentric cam 50. As the eccentric cam 50 rotates, the main drive switching arm 46 moves up and down. Thus, one of the wiping unit and the capping unit can be selectively operated.

[0154] Note that the rotational position of the eccentric cam 50 is detected by the main drive switching pulley sensor 61 (see FIG. 2) and utilized to control the rotation of the eccentric cam 50.

[0155] Next, the mechanism an operation of selectively opening/closing one of the valve mechanism of the valve unit 100 will be described with reference to FIGS. 5, 6A and 6B.

[0156] As shown in FIG. 5, the C ink motor 89 is mounted to the base plate 32 at the inner side thereof. The C ink motor gear 86 is fixed to the spindle shaft of the C ink motor 89. The C ink switching arm 87 is pivotably mounted to the spindle shaft of the C ink motor 89 so as to be swingable right and left. The C ink planet gear 85 is rotatably supported by the C ink switching arm 87 and engaged-with the C ink motor gear 86.

[0157] If the C ink motor 89 rotates in normal direction, the C ink switching arm 87 swings in clockwise direction so that the C ink planet gear 85 engages with the C ink pump gear 88. Thus, the C ink pump is actuated by the driving force from the C ink motor 89.

[0158] On the contrary, if the C ink motor 89 is driven in the reverse direction, the C ink switching arm 87 swings in counterclockwise direction so that the C ink planet gear 85 engages with the C ink transmission gear 84. As a result, the driving force from the C ink motor 89 is transmitted to the C ink transmission pulley 83, which shares the rotation axis with the C ink transmission gear 84, the valve driving belt 82, the valve switching pulley 80 (FIG. 2), and finally to the eccentric cam 104 (FIG. 6B). The eccentric cam 104, provided with the driving force, rotates and thereby opens/closes the first through third valve mechanisms 101, 102, 103 in sequence. In other words, while one valve mechanism is opened, the other two valve mechanisms are closed without exception.

[0159] It should be noted that the rotational position of the eccentric cam 104 is detected by the valve switching pulley sensor 81. The rotation of the eccentric cam 104 is controlled based on the detection of the valve switching pulley sensor 81 such that the eccentric cam 104 stops rotating when the required valve mechanism is open.

[0160] Next, the operation of the whole cleaning device will be described with reference to FIG. 8.

[0161] FIG. 8 is a timing chart of the general operation of the cleaning device 6 according to the embodiment of the invention. The vertical axis of FIG. 8 indicates whether each of motors (main driving motor 40, Y ink motor 69, C ink motor 89, M ink motor, K ink motor) is under suspension or rotating in normal or reverse direction. The vertical axis also indicates the occurrence of the preparative discharging of the ink, and the position (up/down) of the cap members 23. The horizontal axis indicates, in sequence, the events (T1 through T19) that occur during the operation of the cleaning device 6. Note that the intervals between the events in the horizontal axis do not correspond to the actual time intervals between the events.

[0162] After a printing operation is carried out, the printhead 5 moves from a printing zone to a location above the cleaning device 6, which is generally called home position or maintenance position. At the home position, the ink ejecting surface of the printhead 5 is normally covered with the cap members 23 to prevent drying of the printhead 5. The cleaning of the printhead 5 is required when the printhead 5 is located at the home position with the ink ejecting surface being covered with the cap members 23, e.g. just after the power of the printer 1 is turned on. When the cleaning is required, the cleaning device 6 starts to operate as illustrated In FIG. 8.

[0163] First, the C ink motor 89 is reversely rotated to open the first valve mechanism 101 and connect the cap vents 23a of the cap members 23, each corresponding to different color ink, with the respective one of the four pumps 130 (T1).

[0164] Next, each of the Y, C, M, and K ink motors is driven in normal direction to actuate the corresponding pump 130 and suck out the ink from the nozzles of the printhead 5 through each cap member 23 for a predetermined time (T2). In this way, dirt that may cause clogging of the nozzle is removed.

[0165] Then, each pump 130 is stopped for a predetermined time (T3) to allow the ink received in each cap member 23 to flow along the inner wall thereof, which is formed in a funnel like shape, toward the bottom or the lowest location of each cap member 23.

[0166] At T4, the C ink motor 89 is reversely rotated to open the second valve mechanism 102 and allow the-cap vent 23a of each cap member 23 to come in fluid communication with the atmosphere.

[0167] Next, the main driving motor 40 is reversely driven to rotate the eccentric cam 53 such that the cap members 23 are slightly moved down and a gap is formed between the cap members 23 and the printhead 5 (T5). It should be noted that the pressure within the cap members 23 Is kept constant during this step since the cap vent 23a is in fluid communication with the atmosphere, and the pressure within the cap members 23 does not decrease as the cap members 23 is detached from the printhead 5. Therefore, the cap members 23 can be easily detached from the ink ejecting surface 5a of the printhead 5. Further, the ink within the nozzles of the printhead 5 will be not sucked out as the cap members 23 moves away from the printhead 5.

[0168] Next, the C ink motor 89 is reversely rotated to drive the eccentric cam 104 until the first valve mechanism 101 Is opened so that the cap vent 23a of each cap members 23 is connected to the corresponding pump 130 again (T6).

[0169] Then, each of the Y, C, M, and K ink motors is driven In normal direction to actuate the respective pump 130 (T7) and thereby suck out the ink remaining in each the cap member 23.

[0170] At T8, the main driving motor 40 is driven again in the reverse direction to move the cap members 23 down to the lowest position thereof.

[0171] Next, the Y ink motor 69 is driven in reverse direction to rotate the eccentric cam 50 and thereby swing the main drive switching arm 46 upwards (T9). As a result, the main driving planet gear 44 engages with the pinion gear 45 and the carriage 26, and hence the wiping unit, becomes to move right and left in accordance with the rotation of the main driving motor 40.

[0172] At T10, the main driving motor 40 is driven in normal direction so that the wiping unit moves from the initial position thereof to the wiping start position (see also FIG. 7B). During this step, the cleaning blade 21 is kept at the inclined position thereof as described in connection with FIG. 7B. Therefore, the cleaning blade 21 passes by the printhead 5 without coming into contact with the ink ejecting surface 5a. Further, as is also described in connection with FIG. 7B, the cleaning blade 21 is moved to the upright position thereof as the wiping unit approaches the wiping start position.

[0173] At T11 and T12, the main driving motor 40 is reversely rotated to move the carriage 26 from the wiping start position to the initial position thereof. Since the cleaning blade 21 is held at the upright position thereof, the tip portion of the cleaning blade 21 is rubbed against the ink ejecting surface 5a of the printhead 5 when the wiping unit passes by the printhead 5, and thereby wipes the ink ejecting surface 5a clean.

[0174] It should be noted that the wiping unit is once stopped just before the cleaning blade 21 comes off the ink ejecting surface 5a (see the transition period between step T11 and T12) to prevent scattering of the ink caused by the springing back of the warped tip portion of the cleaning blade 21 as the cleaning blade 21 is released from the ink ejecting surface 5a.

[0175] Then, the wiping unit is restarted to move toward the initial position thereof (T12). This time, the wiping unit moves below the second absorber 30 with the tip portion of the cleaning blade 21 being rubbed against the under surface of the second absorber 30. Further, as the wiping unit approaches the initial position, the cleaning blade 21 is moved to the inclined position thereof so that the front surface of the cleaning blade 21 comes into contact with the first absorber 31 when the wiping unit is stopped at the initial position.

[0176] At T13, the C ink motor 89 is reversely rotated to open the third valve mechanism 103 and thereby connect the absorber vent 37 a with the pump 130.

[0177] At T14, the main drive switching arm 46 is swung down by rotating the Y ink motor in reverse direction so that the main driving planet gear 44 engages with the transmission gear 51. Thus, if the main driving motor 40 is driven, the eccentric cam 53 rotates and the cap members 23 move up and down.

[0178] At T15, all of the Y, C, M, and K ink motors are driven in normal direction to suck the ink from the first and second absorbers 31, 30 through the absorber vent 37a.

[0179] At T16, the C ink motor 89 is reversely rotated to open the second valve mechanism 102. Thus, the cap vents 23a come in fluid communication with the atmosphere through the second fluid channel.

[0180] In the mean time, the printhead 5 is moved above the flushing unit 7, and the preparative discharge of ink is carried out (T16). This preparative discharge is carried out to discharge the dust pushed into the nozzle by the cleaning blade 21 during the wiping operation at T11 and thereby prevent clogging of the nozzles due to such dust. After the preparative discharge, the printhead 5 moves back above the cap members 23.

[0181] At T17, the main driving motor 40 rotates in normal direction to move the cap members 23 to the uppermost position thereof, i.e., to the location where the cap members 23 cover the ink ejecting surface 5a of the printhead 5. It should be noted that the pressure within the cap members 23 is kept constant during this step since the cap vent 23a is in fluid communication with the atmosphere, and the pressure within the cap members 23 does not increases as the cap members 23 is pressed against the printhead 5. Therefore, the cap members 23 can be easily attached to the ink ejecting surface 5a of the printhead 5. Further, the ink within the nozzles of the printhead 5 will be not pushed back into the printhead 5 as the cap members 23 cover the Ink electing surface 5a.

[0182] At T18, the C ink motor rotates in reverse direction to open the third valve mechanism 103. Thus, the absorber vent 37a comes in fluid communication with the pump 130 via the third fluid channel.

[0183] Then, the cleaning device stands ready to the next cleaning operation (T19).

[0184] As described above, in the cleaning device 6 according to the embodiment, the pump 130 is used for both sucking ink from the cap member 23 and from the first ink absorber 31. Thus, it is not necessary to provide the cleaning device 6 with a large number of suction pumps. Further, the pump 130 is used for sucking ink from only one of the cap member 23 and the first ink absorber 31 at one time. Thus, it is not necessary to provide the cleaning device with a high power pump.

[0185] FIGS. 9A through 9C illustrate a variation of the cleaning process performed by the cleaning device 6 according to the embodiment of the invention. In this variation, the wiping unit is first located at the initial position (1) with the cleaning blade 21 located at the inclined position thereof (FIG. 9A). Then the wiping unit moves to the wiping start position (3). Since the cleaning blade 21 is kept at the inclined position thereof, the tip portion of the cleaning blade 21 does not come into contact with the ink ejecting surface 5a when the wiping unit passes by the printhead 5 (see the broken lines at position (2) in FIG. 9).

[0186] After arriving at the wiping start position, the wiping unit is stopped thereat with the cleaning blade 21 placed at the upright position thereof, as shown in solid lines in FIG. 9B. In the meantime, the cap members 23 moves up to cover the ink ejecting surface 5a of the printhead 5 as shown in broken lines in FIG. 9B and the purging operation described in connection with FIG. 7A is carried out. After the purging operation is finished, the cap members 23 moves down to the lowermost position thereof, as shown in solid lines in FIG. 9B, to make way for the wiping unit.

[0187] Next, the wiping unit moves back toward the initial position (1) with the cleaning blade 21 kept at the upright position thereof. When the wiping unit passes by the printhead 5, the tip portion of the cleaning blade 21 is rubbed against the ink ejecting surface 5a and thereby wipes off the ink ejecting surface Sa (see the broken line at position (4) in FIG. 9C).

[0188] It should be noted that the wiping unit is stopped for a while just before the cleaning blade 21 comes off the ink ejecting surf ace 5a to prevent the scattering of the ink due to the strong spring back of the warped tip of the cleaning blade 21.

[0189] After the wiping unit restarts and moves below the second absorber 30 toward the initial position (1) (see the broken lines at position (5) in FIG. 9C). The tip portion of the cleaning head is rubbed against the under surface of the second absorber 30 since the cleaning blade 21 is held at the upright position thereof. Thus, the ink adhered to the tip portion of the cleaning blade 21 is removed by the second absorber 30.

[0190] Shortly before the wiping unit arrives at the initial position (1), the cleaning blade 21 is turned to the inclined position thereof. Thus, when the wiping unit is located at the initial position (1), the cleaning blade 21 comes into contact with the first absorber 31 at substantially the entire side surface thereof, as shown in solid lines in FIG. 9C, and the ink adhered to the cleaning blade 21 will be absorbed by the first absorber 31.

[0191] FIG. 10 is a timing chart of the operation of the cleaning device, that performs the cleaning process in a manner as shown in FIGS. 9A through 9C. The timing chart shown in FIG. 10 is substantially the same as that illustrated in FIG. 8 except the following two points. The first difference is that step T10 is canceled. The second difference is that additional steps T31 through T37 are performed before step T1.

[0192] Thus, cleaning process shown in FIG. 10 initiates with reversely rotating the C ink motor 89 to open the second valve mechanism 102 and allow the cap vent 23a of each cap member 23 to come in fluid communication with the atmosphere.

[0193] Then, the main driving motor 40 is reversely driven to rotate the eccentric cam 53 such that the cap members 23 are moved down to the lowermost position thereof (T32).

[0194] Next, the Y ink motor 69 Is driven in reverse direction to rotate the eccentric cam 50 and thereby swing the main drive switching arm 46 upwards (T33). Thus, the main driving planet gear 44 engages with the pinion gear 45. In this way, the carriage 26, and hence the wiping unit, becomes to move right and left in accordance with the rotation of the main driving motor 40.

[0195] At T34, the carriage 26, and hence the cleaning blade 21 is moved from the initial position to the wiping start position. This is achieved by driving the main driving motor 40 in normal direction. It should be noted that the cleaning blade 21 is kept at the inclined position thereof during this step. It should be also noted that the cleaning blade 21 is moved to the upright position thereof as the wiping unit approaches the wiping start position.

[0196] Then, the main driving motor 40 rotates in normal direction to move the cap members 23 to the uppermost position thereof, i.e., to the location where the cap members 23 come into close contact the ink ejecting surface 5a of the printhead 5 (T36).

[0197] After step T37, steps T1 through T9 and steps T11 and T19 are carried out in sequence. The detailed descriptions of these steps, however, will be omitted since they are already described in connection with FIG. 8.

[0198] FIGS. 11A through 11C illustrate another variation of the cleaning process performed by the cleaning device 6 according to the embodiment of the invention.

[0199] In this variation, the wiping unit is first located at the rearmost position thereof or the wiping start position (11), as shown in FIG. 11A. Note that the cleaning blade 21 is at the upright position thereof at this state.

[0200] While having the wiping unit at the wiping start position (11), the cap members 23 moves up to cover the ink ejecting surface 5a of the printhead 5 as shown in broken lines in FIG. 11A and the purging operation described in connection with FIG. 7A is carried out. After the purging operation is finished, the cap members 23 moves down to the lowermost position thereof, as indicated in solid lines in FIG. 11A, to make way for the wiping unit.

[0201] Next, the wiping unit moves toward the first absorber 31, or a wiping end position, with the cleaning blade 21 kept at the upright position thereof (see FIG. 11B). Thus, when the wiping unit passes by the printhead 5, the tip portion of the cleaning blade 21 is rubbed against the ink ejecting surface 5a and wipes off the ink ejecting surface 5a (see the broken line at position (12) in FIG. 11B).

[0202] The wiping unit stops for a predetermined time just before the cleaning blade 21 comes off the ink ejecting surface 5a to prevent the scattering of ink due to the spring back of the cleaning blade 21.

[0203] Then the wiping unit restarts and moves below the second absorber 30 with the tip portion of the cleaning head 21 being rubbed against the second absorber 30 (see the broken line at position (13) in FIG. 113.

[0204] Then, the wiping unit arrives at the first absorber 31 or the wiping end position (see the solid line at position (14) in FIG. 11B). At the wiping end position, the cleaning blade 21 is located at the inclined position thereof so that substantially the entire side surface thereof abuts against the first absorber 31. The wiping unit is kept at the position (14) for a while to allow the ink on the cleaning blade 21 to be removed by the first absorber 31. Then, the wiping unit returns to the wiping start position (11) as shown in FIG. 11C. On the way back to the wiping start position, the cleaning blade 21 is kept at the inclined position. Therefore, the cleaning blade 21 does not come Into contact with the ink ejecting surface 5a when the wiping unit passes by the printhead 5.

[0205] The cleaning blade 21 is returned to the upright position thereof as the wiping unit approaches the wiping start position (11), and the wiping unit stands ready to the next cleaning process at the wiping starting position (11) with the cleaning blade 21 at the upright position as indicated in solid lines in FIG. 1C.

[0206] FIG. 12 is a timing chart of the operation of the cleaning device that performs the cleaning process in a manner as shown in FIGS. 11A through 11C. The timing chart shown in FIG. 12 is substantially the same as that illustrated in FIG. 8 except that step 10 is moved from between steps T9 and T11 to between steps T14 and T15. Thus, detailed description of the timing chart shown in FIG. 12 will be omitted.

[0207] While the invention has been described in connection with a specific exemplary embodiment thereof, it should be understood that the invention is not limited to the above-described exemplary embodiment.

[0208] For example, the ink remaining on the ink ejecting surface may be wiped off by moving the printhead 5 while keeping the cleaning blade 21 stationary instead of moving the cleaning blade 21 relative to the unmoving printhead 5 as in the above described embodiment. In this case, the wiping unit is configured such that the blade actuating plate 24 moves toward/away from the blade supporting plate 22 In accordance with the movement of the printhead 5 so that the cleaning blade 21 moves between the inclined position and the upright position thereof in a suitable timing. To be more specific, the cleaning blade 21 is kept at the inclined position thereof, while the printhead 5 moves towards a wiping start position, so that the tip portion of the cleaning blade 21 does not come into contact with the ink ejecting surface 5a of the printhead 5. Then, when the printhead 5 has arrived at the wiping start position, the blade actuating plate 24 slides under the blade supporting plate 22. As a result, the cleaning blade 21 is moved to the upright position thereof where the tip portion is located high enough to become into contact with the Ink ejecting surface 5a of the printhead 5. Then, the printhead 5 moves in opposite direction so that the tip portion of the cleaning blade 21 wipes across the ink ejecting surface 5a and thereby removes the ink remaining thereon. The blade actuating plate 24 slides away from the blade supporting plate 22 after the wiping has finished, or after the printhead 5 has come off the cleaning blade 21, in order to bring back the cleaning blade 21 to the inclined position thereof.

[0209] It should be noted that, also in the above mentioned case, an ink absorber such as the first absorber 31 may be provided adjacent to the cleaning blade 21 so as to come into contact with the cleaning blade 21 when it is located at the inclined position in order to remove the ink adhered thereto.

[0210] In the embodiment according to the invention, the wiping unit is moved so that the cleaning blade 21 wipes off the ink ejecting surface 5a. The wiping unit is stopped for a while just before the cleaning blade 21 comes off the ink ejecting surface Sa. Then the wiping unit started to move at the same speed as before. The wiping unit is stopped and restarted as above in order to prevent the scattering of ink caused by the spring back of the warped tip portion of the cleaning blade 21 at the moment when the cleaning blade 21 comes off the ink ejecting surface Sa.

[0211] It should be noted that the traveling speed of the wiping unit after the restart may be controlled to be slower than before by changing the driving condition of the main driving motor 40, such as by decreasing the voltage applied thereto or, if the main driving motor 40 is a step motor, by providing less driving pulses to the step motor. The amount of scattered ink decreases as the traveling speed of the wiping unit after the restart decreases. The decrease in the traveling speed of the wiping unit also allows the second absorber 30 to absorb the ink adhered on the tip portion of the cleaning blade 21 in addition to merely wiping off the tip portion. However, since the time required for cleaning should be as short as possible, the traveling speed of the wiping unit after the restart should be determined as fast as possible (as long as the second absorber can satisfactorily remove the ink from the cleaning blade 21) by taking into account the ink absorbing ability of the second absorber 30.