Abstract:
A maintenance apparatus simplifies the cam mechanism for moving a capping mechanism and wiper mechanism, thereby making the printer smaller. A maintenance apparatus  30  has a capping mechanism  40  for covering or sealing the nozzle surface  15  of a print head  12  having nozzles for discharging ink droplets, a wiper mechanism  50  for wiping the nozzle surface  15  of the print head  12 , and a cam  60 . The cam  60  is rotatably disposed solid of revolution having on the side thereof a first cam channel  61  for moving the capping mechanism  40  and a cam channel  62  for moving the wiper mechanism  50.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to a maintenance apparatus for an inkjet-type print head.  
           [0003]    2. Description of the Related Art  
           [0004]    Generally speaking, inkjet printers print by discharging ink drops to a desired position from plural nozzles in a print head mounted on a bidirectionally travelling carriage.  
           [0005]    Maintenance operations for appropriately cleaning the print head in a service area outside of the normal printing area include capping the print head with a cap that enables communication with air when the print head is not used for a long time, an ink vacuuming process for sucking ink that has increased in viscosity (referred to below as “viscous ink”) from inside the nozzles while the print head is sealed with the cap, and a wiping process using a wiper to wipe normal ink, viscous ink, and other contamination from the nozzle surface of the print head.  
           [0006]    Devices performing such maintenance operations must be able to move the cap and wiper toward and away from the print head. A maintenance apparatus according to the related art is therefore typically configured to move the cap in conjunction with movement of the carriage, and to move the wiper along a specific path through a cam mechanism using, for example, the drive power of a pump used for vacuuming ink as the drive power source, or is configured to move the cap and the wiper along separate paths using a similar cam mechanism.  
           [0007]    A problem with a maintenance apparatus according to the related art as noted above is that a longer carriage path must be provided in order for the cap to move in conjunction with carriage movement. This necessarily increases the size of the printer.  
           [0008]    The cap must also be movable between three distinct positions: a retracted position where the cap is separated from the print head, a capping position where the cap covers the nozzle surface of the print head, and a sealed position where the nozzle surface is completely sealed for vacuuming ink from the nozzles. The cam mechanism required for the cap to move between these three positions independently of wiper movement is, however, complex and independent movement can be difficult to achieve.  
           [0009]    More particularly, the space inside the cap must be able to communicate with the air while the cap covers the nozzle surface when in the capping position. A valve must therefore be provided in the cap, and a further problem is that the mechanism for opening and closing this valve is complex.  
         OBJECTS OF THE INVENTION  
         [0010]    The present invention is directed to a solution to these problems, and an object of the invention is to provide a maintenance apparatus simplifying the cam mechanism for moving the cap and wiper and enabling the printer itself to therefore be made smaller.  
         SUMMARY OF THE INVENTION  
         [0011]    To achieve these objects a maintenance apparatus for maintaining a print head having nozzles for discharging ink droplets and nozzle surface on which the nozzles are disposed, according to the present invention has a cap for covering the nozzles; a wiper for wiping the nozzle surface; and a cam member that is a rotatably disposed solid of revolution having on a side part thereof a first cam part for moving the cap and a second cam part for moving the wiper.  
           [0012]    By linking movement of the cap and wiper using the first and second cam parts of the cam member, the present invention can cover or seal the print head with the cap without linking the capping mechanism to print head movement as in the related art. A printer comprising a maintenance apparatus according to the present invention can therefore be made smaller and the cam mechanism can be simplified because a single cam member is sufficient and a complicated cam mechanism is not required.  
           [0013]    Further preferably, the maintenance apparatus also has a first slider movably supporting the cap and engaging the first cam part of the cam member to move the cap toward or away from the nozzle surface. A spring is also preferably positioned between the first slider and cap for urging the cap toward plane of the nozzle surface of the print head. The cap also preferably has a through-hole for communicating with air, and the first slider has a valve for opening and closing the through-hole. Yet further preferably, in this case, the first cam part of the cam member has a cam face for moving the cap between a sealed position whereat the valve is closed and the nozzles are covered, a covered position whereat the valve is open and the nozzles are covered, and a retracted position separated from the print head, in conjunction with cam member rotation.  
           [0014]    Driving a pump communicating with the cap when the cap is in the sealed position can purge ink inside the nozzles of the print head. When the cap is in the covered position the cap communicates with the air through the through-hole. Driving the pump in the covered position without vacuuming ink from the nozzles can therefore purge ink inside the cap. The first slider when pressed against the print head movably supports the cap, and the sealed and covered positions of the cap can therefore be set within the range of first slider movement. The cap can therefore be moved between the sealed position and covered position by simply changing the position of the slider, that is, by rotating the cam member.  
           [0015]    The through-hole is preferably formed in the back of the cap and the valve is formed on the first slider at a position opposing the through-hole. The through-hole separates from the valve and the valve opens due to action of the spring when the cap moves from the sealed position to the covered position. The cap can therefore be easily changed from the sealed position to the covered position without using a complex valve mechanism.  
           [0016]    Yet further preferably, the cam face of the first cam part has areas where the cap remains in each of the sealed position, the covered position, and the retracted position as the cam member rotates through a respective specific angle. This makes it easier to control movement of the cap to each of these positions.  
           [0017]    Yet further preferably, the first slider has a lock part for fixing the print head in its home position. By making this lock part an integral part of the first slider the print head can be fixed in conjunction with movement of the first slider. It is therefore not necessary to provide a separate member for fixing the print head position and a mechanism for moving this separate member, and the capping mechanism itself is therefore simplified.  
           [0018]    Yet further preferably, the second cam part of the cam member has a cam face for moving the wiper in conjunction with rotation of the cam member between a retracted position separated from the print head and plural wiping positions at different distances from the retracted position. By thus using a mechanism for changing the wiper position the wiper can be moved between, for example, a first wiping position for cleaning the nozzles and a second wiping position for cleaning the wiper itself, thereby enabling more precise maintenance. The cam face of the second cam part further preferably has areas where the wiper remains in each of the first wiping position, the second wiping position, and the retracted position as the cam member rotates through a respective angle. This makes it easier to control the movement of the wiper to each of these positions.  
           [0019]    The first and second cam parts of the cam member are preferably related such that the wiper is in the retracted position when the cap is in the sealed position or covered position, and the cap is in the retracted position when the wiper is in a wiping position. The cap thus does not move during the wiping process, and the wiping operation can therefore be run independently of the capping process and ink vacuuming process.  
           [0020]    Furthermore, by making the maintenance apparatus smaller, the present invention also enables reducing the size of the printer, and the control components can also be simplified because the maintenance process can be accomplished by controlling primarily the angle of cam member rotation.  
           [0021]    Other objects and attainments together with a fuller understanding of the invention will become apparent and appreciated by referring to the following description and claims taken in conjunction with the accompanying drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0022]    In the drawings wherein like reference symbols refer to like parts.  
         [0023]    [0023]FIG. 1 is an oblique view showing the basic configuration of a printer according to the present invention;  
         [0024]    [0024]FIG. 2 is an oblique view showing the printer in FIG. 1 partially disassembled;  
         [0025]    [0025]FIG. 3 is an oblique view showing the basic configuration of a maintenance apparatus according to the present invention;  
         [0026]    [0026]FIG. 4 is a plan view of the maintenance apparatus shown in FIG. 3  
         [0027]    [0027]FIG. 5 is a section view showing the capping mechanism and cam member of the maintenance apparatus shown in FIG. 4;  
         [0028]    [0028]FIG. 6 is a cam diagram showing the first cam groove and second cam groove of the cam member shown in FIG. 5;  
         [0029]    [0029]FIG. 7 is an oblique view showing essential components of the print head mechanism, capping mechanism, and wiper mechanism of the printer shown in FIG. 1;  
         [0030]    [0030]FIG. 8 is a plan view of the components shown in FIG. 7;  
         [0031]    FIGS.  9 ( a ) and ( b ) show the relative positions of the print head and wiper mechanism in a cleaning process according to the present invention;  
         [0032]    FIGS.  10 ( a ) to ( d ) show the relative positions of the print head and wiper in a print head cleaning process according to the present invention;  
         [0033]    FIGS.  11 ( a ) to ( c ) show the relative positions of print head and wiper in a wiper cleaning process according to the present invention; and  
         [0034]    [0034]FIG. 12 is a block diagram showing the control system of a printer according to the present invention. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0035]    A preferred embodiment of a maintenance apparatus according to the present invention and a printer comprising this maintenance apparatus is described below with reference to the accompanying figures.  
         [0036]    [0036]FIG. 1 is an oblique view showing the basic configuration of a printer according to this embodiment of the invention. FIG. 2 is an oblique view showing the printer in FIG. 1 partially disassembled. FIG. 3 is an oblique view showing the basic configuration of a maintenance apparatus according to the present invention. FIG. 4 is a plan view of the maintenance apparatus shown in FIG. 3. FIG. 5 is a section view showing the capping mechanism and cam member of the maintenance apparatus shown in FIG. 4. FIG. 6 is a cam diagram showing the first cam groove and second cam groove of the cam member shown in FIG. 5. FIG. 7 is an oblique view showing essential components of the print head mechanism, capping mechanism, and wiper mechanism of the printer shown in FIG. 1. FIG. 8 is a plan view of the components shown in FIG. 7.  
         [0037]    As shown in FIG. 1 and FIG. 2, a printer  1  according to this embodiment of the invention has a box-like main frame  2  with a print head drive mechanism  10  disposed in the middle of the main frame  2 . The print head drive mechanism  10  has a carriage shaft  11  extending lengthwise to the main frame  2 . A carriage  17  is movably supported on the carriage shaft  11 .  
         [0038]    A block-shaped print head  12  is mounted on the carriage  17 . A nozzle surface  15  (shown in FIG. 7 and FIG. 8) with a plurality of nozzles is formed on the front of the print head  12  so that ink supplied through ink tubes  7  (FIG. 7) can be selectively discharged from individual nozzles.  
         [0039]    The carriage  17  on which the print head  12  is mounted is moved bidirectionally along carriage shaft  11  by driving a motor  13 .  
         [0040]    As shown in FIG. 1 and FIG. 2, a cartridge holder  5  in which ink cartridge  3  and ink cartridge  4  can be loaded and unloaded is positioned at the back of the main frame  2  (the bottom in FIG. 1 and FIG. 2). Ink cartridge  3  is filled with a first color ink (such as black ink). Ink cartridge  4  is internally separated into an ink supply chamber and waste ink chamber (not shown in the figure). The ink supply chamber is filled with a second color ink (such as red ink). An absorbent body for absorbing waste ink is contained in the waste ink chamber. The first and second colors of ink are supplied from the ink cartridges  3  and  4  to the print head  12  when the ink cartridges  3  and  4  are installed in the cartridge holder  5 .  
         [0041]    A paper guide  6  and paper feed mechanism  20  are located in the front (top as seen in FIG. 1 and FIG. 2) of the main frame  2 . The paper guide  6  and paper feed mechanism  20  are both a specific length shorter than the carriage shaft  11 ; that is, are approximately the same length as the width of the printing paper, and are positioned offset a specific distance from one side  2   a  of the main frame  2  so as to leave a specific space therebetween.  
         [0042]    The paper feed mechanism  20  advances printing paper located on or guided by the paper guide  6  between the print head  12  and an opposing platen  22  by driving a motor  23  (shown in FIG. 12) to rotate paper feed roller  21 .  
         [0043]    The maintenance apparatus  30  is positioned in at the front of the main frame  2  so as to occupy the space between the paper feed mechanism  20  and main frame side  2   a . More specifically, with reference to FIG. 2, the maintenance apparatus  30  has an L-shaped substrate  31 , a motor  71 , pump  80 , capping mechanism  40 , wiper mechanism  50 , and power transfer mechanism  70  for transferring drive power from the motor  71  to the capping mechanism  40 , wiper mechanism  50 , and pump  80 . The capping mechanism  40  and wiper mechanism  50  are positioned between the paper feed mechanism  20  and side  2   a  of main frame  2 , and the power transfer mechanism  70  and pump  80  are both disposed between paper feed mechanism  20  and the bottom  2   b  of the main frame  2 .  
         [0044]    A case-like support unit  32 , open in part, is integrally formed with the substrate  31 . The capping mechanism  40  and wiper mechanism  50  are supported by the support unit  32 . When the print head drive mechanism  10 , paper feed mechanism  20 , and maintenance apparatus  30  are assembled on the main frame  2  the printing area is at the front of the platen  22  in the paper feed mechanism  20  and the maintenance area is at the front of the support unit  32  supporting the capping mechanism  40  and wiper mechanism  50 . The print head  12  can move along the carriage shaft  11  between the printing area and maintenance area. The nozzle surface  15  is opposite the platen  22  when the print head  12  is in the printing area, and is opposite cap  43  or wiper  52  when the print head  12  is in the maintenance area.  
         [0045]    The power transfer mechanism  70  for transferring drive power from the motor  71  to the capping mechanism  40 , wiper mechanism  50 , and pump  80  is a gear train comprising multiple gears. When the motor  71  turns in the normal (forward) direction, drive power is transferred to the pump  80 ; when the motor  71  turns in the opposite (reverse) direction, power is transferred to the capping mechanism  40  and wiper mechanism  50 .  
         [0046]    The intake opening  81  of the pump  80  (FIG. 3) is connected to the cap  43  through a tube  45  (FIG. 5), and the outlet  82  is connected to the waste ink chamber of the ink cartridge  4  through a tube not shown in the figures. When the pump  80  is driven ink is suctioned from the nozzles of the print head  12  through the cap  43  and discharged into the waste ink chamber of the ink cartridge  4 .  
         [0047]    Referring to FIGS. 3, 4, and  5 , a cylindrical cam  60  is connected to the last stage (the capping mechanism  40  and wiper mechanism  50  side) of the gear train in the power transfer mechanism  70 . A first cam channel  61  (first cam part) for sliding the cap  43 , and a second cam channel  62  (second cam part) for sliding the wiper  52 , are separately formed on the circumferential surface of the cam  60 . The cam  60  is thus part of the capping mechanism  40  and part of the wiper mechanism  50 .  
         [0048]    More specifically as further described below, a cam follower  46  for engaging the cam channel  61  is formed on the slider  41  of the capping mechanism  40  (further described below), and a cam follower  53  for engaging the cam channel  62  is formed in the slider  51  of the wiper mechanism  50 . The slider  41  of capping mechanism  40  and the slider  51  of wiper mechanism  50  thus slide according to cam channels  61  and  62  when cam  60  rotates.  
         [0049]    The capping mechanism  40  has a slider  41 , cap holder  42 , and cap  43 . The slider  41  is shaped like a case and is supported by the support unit  32  so as to slide orthogonally to the carriage shaft  11 ; that is, in the direction moving toward and away from the plane of the nozzle surface  15  of the print head  12 .  
         [0050]    As shown in FIG. 5, one end of the slider  41  is open. A divider  41   a  formed in the middle inside the slider  41  divides the slider  41  into a front and a rear section. The cap holder  42  is supported in the front section so that it can slide relative to the slider  41 . The cap  43  is affixed to the front of the cap holder  42 . The cap  43  is a box-shaped elastomeric structure with an opening of a size able to cover the nozzles of the print head  12 . A multilayer ink absorbent body  43   a  is disposed in this opening.  
         [0051]    As also shown in FIG. 5, a valve mechanism  47  for opening and closing a valve communicating with the cap  43  is disposed between the cap  43  and slider  41  so that the inside of the cap  43  can be cut off from or opened to the air. A tube  43   b  extending in the sliding direction of the cap holder  42  is disposed at the back part of the cap  43 . A through-hole  43   c  enabling the space inside the cap  43  to communicate with the air is provided in the tube  43   b . A valve head  41   b  that can contact the end face of tube  43   b  forming a valve seat and close the through-hole  43   c  is disposed in the divider  41   a  of slider  41 . A compression spring  44   a  is disposed between the cap  43  and the slider  41  surrounding tube  43   b  and the valve  41   b . Note that tube  45  communicating with the pump  80  is disposed at the back of the cap  43  and another compression spring  44   b  is disposed around this tube  45  between the cap  43  and slider  41 .  
         [0052]    The through-hole  43   c  is opened and closed by sliding the slider  41 . The slider  41  can be positioned so that the valve is closed when the cap  43  is tight against the nozzle surface of the print head  12  (sealed position), so that the valve is open when the cap  43  is tight against the nozzle surface (covered position), or so that the cap  43  is separated from the nozzle surface of the print head  12  (retracted position).  
         [0053]    As will be appreciated from FIG. 6, the sealed and closed positions of the cap  43  are separated distances L 1  and L 2  (&lt;L 1 ), respectively, toward the print head  12  from the retracted (standby) position. When the cap  43  is in the sealed position, the cap  43  is pinched between the slider  41  and print head, and the through-hole  43   c  is closed by valve  41   b . When the cap  43  is in the covered position, the cap  43  is urged toward the print head by the compression spring  44 , a gap of L 1 -L 2  is created between the cap  43  and slider  41 , and the through-hole  43   c  thus opens.  
         [0054]    The shape of the cam channel  61  is determined by the relationship between the rotational angle of the cam  60  and the distance of slider  41  travel. The cam channel  61  includes three circular arc parts  61   b ,  61   c ,  61   a  for holding the cap  43  in the sealed position, covered position, or retracted (standby) position. More specifically, the cam channel  61  is a spiral channel formed on the surface of the cam  60 , the spiral being formed by the circular arc parts  61   b ,  61   c , and  61   a . The cap  43  remains in each of these positions as the cam  60  rotates though a respective angle.  
         [0055]    With the 0° angular position of cam  60  defined as shown in FIG. 6, cam channel part  61   a  for holding the cap  43  in the retracted position extends from 135° to 290°, cam channel part  61   b  for holding the cap  43  in the sealed position extends from 350° to 30°, and cam channel part  61   c for holding the cap  43  in the covered position extends from 45° to 85° . Transitional parts of the spiral cam channel  61  between 30° and 45°, between 85° and 135° and between 290° and 350° interconnect these cam channels parts  61   a ,  61   b , and  61   c.    
         [0056]    A lock part  41   c (FIGS. 3 and 4) for fixing the print head  12  position is further disposed at the end of the slider  41  to hold the print head  12  in its home position.  
         [0057]    As shown in FIG. 4, the wiper mechanism  50  has a slider  51  and wiper  52 . The slider  51  is a box-shaped configuration supported on the support unit  32  so as to slide in the same direction as the slider  41  of the capping mechanism  40 . An elastomeric blade-like wiper  52  is embedded in the end of the slider  51 . The slider  51  can move between a retracted position at which the wiper  52  is pulled farthest inside the maintenance apparatus, a head cleaning position (first wiping position) where ink and foreign matter is wiped off the nozzle surface  15  by the wiper  52 , and a wiper cleaning position (second wiping position) farther toward the print head  12  than the first position. In the head cleaning position the leading edge of the wiper  52  projects a distance sl beyond the nozzle surface  15  toward the base of the print head as shown in FIG. 10, and in the wiper cleaning position the leading edge of the wiper  52  projects a distance s 2  (s 2 &gt;s 1 ) as shown in FIG. 11.  
         [0058]    The shape of the cam channel  62  is determined by the relationship between the rotational angle of the cam  60  and the distance slider  51  travels, similarly to cam channel  61  and the slider  41  of capping mechanism  40 . More specifically, as shown in FIG. 6, the cam channel  62  is a spiral formed of three circular arc parts  62   a ,  62   b ,  62   c  for holding the wiper  52  in the head cleaning position, wiper cleaning position, and retracted (standby) position. The wiper  52  remains in each of these positions as the cam  60  rotates through a respective angle.  
         [0059]    In this embodiment of the invention as shown in FIG. 6, cam channel part  62   c  for holding the wiper  52  in the retracted position extends from an angular position of 270° to 85°, cam channel part  62   a  for holding the wiper  52  in the head cleaning position extends from 135° to 170°, and cam channel part  62   b  for holding the wiper  52  in the wiper cleaning position extends from 180° to 200°. Transitional parts of the spiral cam channel  62  between 85° and 135° between 170° and 180° and between 200° and 270° interconnect these cam channels parts  62   a ,  62   b , and  62   c .  
         [0060]    Cam channels  61  and  62  are correlated so that advancing and retracting the cap  43  is synchronized with advancing and retracting the wiper  52  as described below. More specifically, the cam channels  61  and  62  are formed so that when the wiper  52  is in the head cleaning and wiper cleaning positions the cap  43  is held in the retracted position, and when the cap  43  is in the sealed and covered positions the wiper  52  is held in the retracted position. Rotation of a single cylindrical cam  60  thus coordinates movement of the cap  43  and wiper  52  closer to and away from the print head  12 .  
         [0061]    In this embodiment of the invention as shown in FIG. 6, cam channels  62   a  and  62   b  determining the head cleaning position and wiper cleaning position of the wiper  52  are formed in the same range as the cam channel part  61   a  determining the retracted position of the cap  43 , that is, between 135° and  290 ° of the rotational angle of the cam  60 . In addition, cam channel parts  61   b  and  61   c  determining the sealed position and covered position of the cap  43  are disposed in the same rotational angle range as the cam channel  6   c  determining the retracted position of the wiper  52 , that is, between 270° and 85°.  
         [0062]    A detector  72  (shown in FIG. 12) for detecting the home position of the cam  60  is also positioned on the substrate  31 . A home position is defined as the 60° rotational angle of the cam  60  as shown in FIG. 6. The positions of the cap  43  and wiper  52  are determined by rotating the cam  60  referenced to this home position.  
         [0063]    As shown in FIG. 7, a substantially L-shaped remover  56  is formed from a thin metal sheet with a specific flexibility. One end of this remover  56  is fastened to maintenance area side  12   a  of the print head  12  so that the remover  56  is cantilevered at a specific angle to the side  12   a . The edge of the free end of the remover  56  is bent to the inside (toward the side  12   a ) like a hook to form a rake member  56   a  for raking ink and foreign matter from the wiper  52 . The wiper  52  can thus be inserted between the rake  56   a  and side  12   a  of print head  12 .  
         [0064]    The rake  56   a  is positioned slightly below the plane of the nozzle surface  15  of print head  12  so that when the print head  12  moves through the printing area the remover  56  does not contact the printing paper on the platen  22 .  
         [0065]    At one edge of the nozzle surface  15  a wiper cleaner (second remover)  16  for wiping ink from the wiper  52  is formed. More particularly, as best shown in FIGS. 7 and 10, a step is formed at a certain depth away from the nozzle surface  15  on the side of the print head  12  opposite to the side  12   a  at which the remover  56  is disposed. The wiper cleaner  16  is a sloped surface that connects the step to the nozzle surface  15  and is effective to remove to some extent foreign matter adhering to the wiper  52  by simply moving the print head  12  as will be described in detail later. The cleaning effect of the wiper cleaner  16  can reduce the frequency of the cleaning process in which the wiper  52  is moved for cleaning by the remover  56 .  
         [0066]    [0066]FIG. 12 is a block diagram showing the control system of a printer according to this embodiment of the invention. As shown in FIG. 9 the control unit  55  controls the print head  12  of the print head drive mechanism  10  and motor  13  for moving the print head  12  positioned on carriage  17 , motor  23  for the paper feed mechanism  20 , and motor  71  for the maintenance apparatus  30 . These motors  13 ,  23 , and  71  are stepping motors. The control unit  55  controls the various mechanisms by appropriately applying pulse signals to the motors  13 ,  23 , and  71 . The control unit  55  primarily comprises a microprocessor mounted on a circuit board, firmware for controlling the mechanisms, and ROM, RAM, or other memory for storing and running the firmware.  
         [0067]    The control unit  55  controls positioning of the print head  12  in the widthwise direction of the printing paper by controlling the rotary amount of motor  13 , and controls the rotational angle of the cam  60  by controlling the rotary amount of motor  71 . The detector  14  is positioned within the range of movement of print head  12  for detecting the absolute position of the print head  12 . Positioning control of the print head  12  is based on output from the detector  14 . Rotational angle control of the cam  60  is based on output from detector  72 , thus controlling the positions of the wiper  52  and cap  43 .  
         [0068]    The control unit  55  also controls driving the pump  80  to vacuum ink from the print head  12  and discharge the ink to the waste ink chamber of the ink cartridge  4  by driving the motor  71  in the normal (forward) direction when the cap  43  is in the sealed position.  
         [0069]    FIGS.  9 ( a ) and ( b ) show the relative positions of the print head and wiper mechanism in a print head and wiper cleaning process according to the present invention.  
         [0070]    FIGS.  10 ( a ) to ( d ) show the relative positions of the print head, remover, and wiper in a print head cleaning process according to the present invention.  
         [0071]    FIGS.  11 ( a ) to ( c ) show the relative positions of print head, remover, and wiper in a wiper cleaning process according to the present invention.  
         [0072]    The maintenance method according to this embodiment of the invention includes a print head cleaning process for wiping ink and foreign matter adhering to the nozzle surface  15  of the print head  12 , a wiper cleaning process for removing foreign matter adhering to the wiper  52 , and a nozzle purging process for sucking ink from inside the nozzles of the print head  12  to prevent or remove nozzle clogging. It should be noted that when a printing process is not running, or more specifically when the print head  12  is in the standby position, the cap  43  of capping mechanism  40  is in the covered position and the wiper  52  of the wiper mechanism  50  is in the retracted position.  
         [0073]    For the nozzle purging process the control unit  55  moves the cap  43  from the covered position to the sealed position. More specifically, the control unit  55  drives the motor  71  by a number of pulses equivalent to the desired rotary angle, causing the cam  60  to turn a specific angle of rotation (60°−&gt;10° in FIG. 6). The direction of rotation of motor  71  is then changed to drive the pump  80 . The through-hole  43   c  is thus closed by valve  41   b  of slider  41  and the nozzle surface of the print head  12  is completely sealed by the cap  43  at this time so that driving the pump  80  lowers the pressure inside the cap  43 , thereby sucking ink from inside the nozzles. The ink is then expelled through tube  45  to the waste ink chamber of the ink cartridge  4 .  
         [0074]    After driving the pump  80  for a specified time the control unit  55  stops motor  71  and again changes the direction of motor rotation, then drives the cam  60  a specific angle (10°−&gt;60° in FIG. 6) and returns the cap  43  from the sealed position to the covered position. The control unit  55  then again changes the direction of rotation of motor  71  and again drives the pump  80 . While the nozzle surface of print head  12  is covered by the cap  43  at this time the through-hole  43   c  is open. Driving the pump  80  therefore does not suck ink from the nozzles but rather discharges only the ink held in the absorbent body  43   a  of the cap  43  through tube  45  into the waste ink chamber of the ink cartridge  4 . The control unit  55  then stops the motor  71  and ends the nozzle purging process after the pump  80  eliminates an amount of ink collected in the absorbent body  43   a  of the cap  43 . It should be noted that the cap  43  is left in the covered position in order to prevent variation in the pressure inside the cap  43  due to temperature changes and to prevent disruption of the ink meniscus inside the nozzles when the printer is not used for a long time.  
         [0075]    The print head cleaning process when the print head  12  is in the standby position starts with the control unit  55  moving the wiper  52  from the retracted position to the head cleaning position S 1  where the wiper  52  extends distance s 1  beyond the plane PL of the nozzle surface  15  of the print head  12 . More specifically, the control unit  55  drives the motor  71  the number of pulses equivalent to the desired wiper  52  travel distance, causing the cam  60  to turn a specific angle of rotation (60°−&gt;150° in FIG. 6). This rotation of the cam  60  also moves the cap  43  to the retracted position.  
         [0076]    When in this head cleaning position the wiper  52  is opposite the wiper cleaner  16  of the print head  12  as shown in FIG. 9( a ) and FIG. 10( a ). The control unit  55  then drives the motor  13  of the print head drive mechanism  10  a specific pulse count to move the print head  12  from the maintenance area toward the printing area. More specifically, the print head  12  moves from the head cleaning start position P 1  shown in FIG. 9( a ) to the wiper cleaning start position P 2  shown in FIG. 9( b ).  
         [0077]    As the print head  12  moves, the wiper  52  first contacts the wiper cleaner  16  of the print head  12  and then bends an amount determined by distance s 1  as it slides over the nozzle surface  15  of the print head  12  as shown in FIG. 10( b ), thereby transferring ink adhering to the nozzle surface  15  to the wiper  52  and thus removing it from the nozzle surface  15 . Note that the wiper cleaner  16  scrapes across the surface of the wiper  52  and can thus remove an amount of ink remaining on the wiper  52  when the wiper  52  rides up over the wiper cleaner  16  before sliding across nozzle surface  15 .  
         [0078]    The print head  12  then moves toward the printing area, causing the wiper  52  to separate from the nozzle surface  15  of the print head  12  as shown in FIG. 10( c ), and stops at position P 11 , at which point the wiper  52  is in contact with the rake  56   a  of the remover  56 . When the wiper  52  contacts the rake  56   a  of remover  56  it remains bent as when sliding across the nozzle surface  15 .  
         [0079]    With the print head  12  stopped at position P 11  the control unit  55  moves the wiper  52  from the head cleaning position S 1  to the retracted position as shown in FIG. 10( d ). More specifically, the control unit  55  drives the motor  71  by a pulse count equivalent to the desired travel distance to turn the cam  60  a specific angle of rotation (150°−&gt;60° in FIG. 6). When the wiper  52  moves toward the retracted position, ink  9   b  is removed by the rake  56   a  from a length of the end of the wiper  52  approximately equal to distance s 1  and held by the remover  56 . Ink at a distance greater than length s 1  from the end of the wiper  52  remains on the wiper  52 . The wiper  52  separates gradually from the remover  56  and thus returns slowly from the bent position to the normal position, thereby preventing ink  9   a  on the wiper  52  and ink  9   b  on the remover from being propelled off the wiper or remover and scattering.  
         [0080]    In the wiper cleaning process the control unit  55  stops the print head  12  as shown in FIG. 9( b ) so that when the wiper  52  moves to the wiper cleaning position S 2  the wiper  52  is positioned between the remover  56  and side  12   a  of print head  12  (wiper cleaning start position P 2 ).  
         [0081]    The control unit  55  next moves the wiper  52  from the retracted position to the wiper cleaning position S 2  at which the wiper  52  projects distance s 2  beyond the plane PL of the nozzle surface  15  of the print head  12  as shown in FIG. 11( a ). More specifically, the control unit  55  drives the motor  71  by a pulse count equivalent to this distance s 2  to drive the cam  60  a specific rotational angle (60°−&gt;190° in FIG. 6). The free end of the wiper  52  thus advances past the nozzle surface  15  of the print head  12  and enters space or gap between the remover  56  and side  12   a  of print head  12 .  
         [0082]    As shown in FIG. 11( b ), the control unit  55  then drives the motor  13  of print head drive mechanism  10  by a specific pulse count to move the print head  12  to position P 21  where the rake  56   a  of remover  56  contacts wiper  52 . This causes the remover  56  to deflect slightly.  
         [0083]    As shown in FIG. 11( c ), the control unit  55  then drives the motor  71  to turn the cam  60  a specific angle of rotation (190°−&gt;60° in FIG. 6) so as to move the wiper  52  from the wiper cleaning position S 2  toward the retracted position. As the wiper  52  separates from the rake  56   a  of remover  56 , the elastic force corresponding to the deflection of the remover  56  enables the rake  56   a  to scrape part  9   e , equivalent to distance s 2 , of the ink  9   c  adhering to the wiper  52  from the wiper  52 .  
         [0084]    The amount of ink  9   d  remaining on the wiper  52  when the wiper  52  returns to the retracted position from the wiper cleaning position S 2  is thus less than the amount of ink  9   a  remaining on the wiper  52  when it returns from the head cleaning position S 1  to the retracted position. This wiper cleaning process thus makes it possible to remove ink from an area at the end of the wiper  52  greater than the area corresponding to distance s 1  used for the next head cleaning process.  
         [0085]    By thus using a remover  56  to appropriately remove ink and other foreign matter that clings to the wiper  52  when the wiper  52  wipes the nozzle surface  15  of the print head  12 , the present invention is able to clean the print head with a part of the wiper  52  devoid of ink, thereby preventing clogging the nozzles of the print head  12  and the resulting dots dropouts.  
         [0086]    As will be appreciated from the preceding description of the present invention, cam channels  61  and  62  of the cam  60  cause cap  43  and wiper  52  to slide in conjunction with each other, thereby enabling the printer size to be reduced and the mechanisms to be simplified as compared with the related art.  
         [0087]    This invention can also move the cap  43  between a sealed position and a covered position without complicating the valve mechanism therefor as compared with the related art. This is achieved by using a capping mechanism  40  with a double-sliding configuration having a slider  41  following the cam  60  and a cap  43  urged by a compression spring  44  intervening between the cap  43  and slider  41 , and by positioning a valve mechanism for opening and closing a valve communicating with the cap  43  according to the sliding distance between the slider  41  and cap  43 .  
         [0088]    Plural wiper  52  positions can also be defined depending upon the shape of cam channel  62  in the present invention, and various wiping processes can therefore be performed.  
         [0089]    The present invention has been described using a groove formed in the circumferential surface of a cylindrical cam for moving the wiper and cap. The invention shall not be so limited, however, as a protruding rail-like member could be formed on the surface of the cylindrical cam to define the wiper and cap movement.  
         [0090]    As described above, the present invention links movement of a cap and wiper by using first and second cam parts of a cam member. The present invention therefore requires only the minimum space required for print head movement and does not link the capping mechanism to the print head as in the related art. The present invention therefore helps reduce the size of a printer having a maintenance apparatus and simplifies the configuration of the cam mechanism because the cam mechanism requires only a single cam member.  
         [0091]    Furthermore, a spring causes the through-hole to separate from the valve so that the valve opens when the through-hole is formed in the back of the cap, the valve is formed opposing the through-hole in the first slider, and the cap moves from the sealed position to the covered position. The cap can thus be switched between sealed and covered states without complicating the valve mechanism.  
         [0092]    Although the present invention has been described in connection with the preferred embodiments thereof with reference to the accompanying drawings, it is to be noted that various changes and modifications will be apparent to those skilled in the art. Such changes and modifications are to be understood as included within the scope of the present invention as defined by the appended claims, unless they depart therefrom.