Abstract:
A flow path connecting device includes a first flow path having a first connector and configured to channel fluids, a second flow path having a second connector and configured to channel fluids, a moving unit configured to move at least one of the first and second connectors, to interconnect the first and second connectors so that the first and second flow paths are communicated with each other, and to separate the first and second connectors from each other, and a control unit configured to control the moving unit, when the first and second connectors separate from each other, to set a relative speed of the first and second connectors to a first speed or less in a period from a start of the separation till a lapse of predetermined time, and set the relative speed to a second speed that is higher than the first speed after the lapse of the predetermined time.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a flow path connecting device for automatically interconnecting flow paths of liquids to communicate with each other or for separating the flow paths from each other, or to a recording apparatus for supplying inks from the outside of a carrier including the flow path connecting device. 
         [0003]    2. Description of the Related Art 
         [0004]    A recent printing apparatus for a business purpose is expected to reduce the number of replacing times and running costs, so that a large capacity is required of an ink tank that contains a printing ink. 
         [0005]    An apparatus that performs printing by moving a carrier having a printing mechanism in a direction perpendicular to a printing sheet feeding direction generally mounts an ink tank on the carrier. 
         [0006]    However, this method has disadvantages, for example, if size of the carrier or weight of the ink tank is increased the speed of the carrier will decrease, or the size of a carrier motor must be increased to compensate for the reduction in speed. To solve such a problem, the ink tank can be arranged separately from the carrier, and the carrier printing mechanism and the ink tank can be interconnected through a tube. 
         [0007]    In such a tube connection method, the length of the tube needs to be set in anticipation of carrier movement. This method also has problems such as a detrimental influence of tube rigidity on the carrier movement, incursion of air into the ink from the outside of the tube, and evaporation of ink water to the outside of the tube, which makes it difficult to select a tube material. 
         [0008]    As an example of a solution to the aforementioned problems, an ink supply mechanism is discussed in Japanese Patent Application Laid-Open No. 2002-113879. In this ink supply mechanism, a connection mechanism that divides an ink supply path is disposed between an apparatus main-body having a large-capacity ink tank and a moveable carrier having a printing mechanism. The connection mechanism at main-body side and the connection mechanism at a carrier-side are configured such that an ink flow path is formed to supply the ink to the carrier side when connected together, and leakage of the ink from each connection mechanism can be prevented when separated from each other. 
         [0009]    However, in the case of the supply mechanism and the operation discussed in Japanese Patent Application Laid-Open No. 2002-113879, there is a possibility that when the connection mechanisms are separated from each other, the ink left in each connection mechanism will scatter and contaminate a printing sheet. 
       SUMMARY OF THE INVENTION 
       [0010]    The present invention is directed to a mechanism for preventing or reduce the scattering of the ink from such a connection portion. 
         [0011]    According to an aspect of the present invention, a flow path connecting device includes a first flow path having a first connector and configured to channel fluids, a second flow path having a second connector and configured to channel fluids, a moving unit operable to move at least one of the first and second connectors, to interconnect the first and second connectors so that the first and second flow paths are communicated with each other, and operable to move at least one of the first and second connectors to separate the first and second connectors from each other, and a control unit configured to control the moving unit, when the first and second connectors separate from each other, to set a relative speed of the first and second connectors to a first speed or less in a period from a start of the separation till a predetermined time expires, and set the relative speed to a second speed that is higher than the first speed after the predetermined time expires. 
         [0012]    According to an exemplary embodiment of the present invention, scattering of fluids caused when the first connector of the first flow path and the second connector of the second flow path are separated from a connected state can be reduced. 
         [0013]    Further features and aspects of the present invention will become apparent from the following detailed description of exemplary embodiments with reference to the attached drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]    The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate exemplary embodiments, features, and aspects of the invention and, together with the description, serve to explain the principles of the invention. 
           [0015]      FIGS. 1A and 1B  are diagrams illustrating behavior of ink. 
           [0016]      FIG. 2  is a perspective diagram illustrating an internal configuration of a printing apparatus according to an exemplary embodiment of the present invention. 
           [0017]      FIG. 3  is a perspective diagram illustrating a carrier portion and an ink supply mechanism of the printing apparatus according to the exemplary embodiment of the present invention. 
           [0018]      FIGS. 4A and 4B  are perspective and sectional diagrams illustrating a negative pressure valve according to the exemplary embodiment of the present invention. 
           [0019]      FIGS. 5A and 5B  are perspective and partially sectional diagrams illustrating a carrier according to the exemplary embodiment of the present invention. 
           [0020]      FIGS. 6A and 6B  are plan and partial sectional diagrams illustrating the printing apparatus according to the exemplary embodiment of the present invention. 
           [0021]      FIGS. 7A and 7B  are plan and partial sectional diagrams illustrating the printing apparatus according to the exemplary embodiment of the present invention. 
           [0022]      FIGS. 8A and 8B  are graphs illustrating speed control and operation control according to the exemplary embodiment of the present invention. 
           [0023]      FIG. 9  is a perspective diagram illustrating an outer appearance of the printing apparatus according to the exemplary embodiment of the present invention. 
           [0024]      FIG. 10  is a perspective diagram illustrating an outer appearance of the printing apparatus according to the exemplary embodiment of the present invention. 
           [0025]      FIG. 11  is a control block diagram of the printing apparatus according to the exemplary embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0026]    Various exemplary embodiments, features, and aspects of the invention will now be described in detail with reference to the drawings. 
         [0027]      FIGS. 9 and 10  are perspective diagrams each illustrating an outer appearance of a printing apparatus (recording apparatus)  1  according to an exemplary embodiment of the present invention. 
         [0028]    The printing apparatus  1  includes a casing cover  901 , a maintenance cover  902 , a guide  903  for supporting a print sheet  906 , and a discharge port  904  for discharging the print sheet  906  which is a printed recording medium. The print sheet  906  is discharged in an arrow direction A. 
         [0029]    The printing apparatus  1  further includes a cover  907  for replacing an ink tank  101  that is replaceably installed in a casing to reserve a liquid. In a state that the cover  907  is open as illustrated in  FIG. 10 , the ink tank  101  is guided in an arrow direction D. When pushed into the casing cover  901  side, the ink tank  101  is coupled with a supply port  307  ( FIG. 3 ). The printing device  1  includes a power switch  905 . 
         [0030]      FIG. 2  is a perspective diagram illustrating an internal configuration of the printing apparatus  1 . A chassis  201  supports the entire internal configuration. A platen  202  supports the print sheet  906 . A roller  203  feeds the print sheet  906 . A pinch roller  204  presses the print sheet  906  to the roller  203 . By rotating the roller  203  by a driving device (not shown), the print sheet  906  is fed in the arrow direction A of  FIG. 9 . 
         [0031]    A carrier  206  is supported to move reciprocally along a shaft  207  and a guide  205  in an arrow direction B. A motor  209  reciprocates the carrier  206  along the shaft  207  and the guide  205  in the arrow direction B via a belt  208 . A maintenance mechanism  210  is configured to maintain a printing mechanism mounted on the carrier  206 . 
         [0032]      FIG. 3  is a perspective diagram illustrating a carrier portion of the printing apparatus  1  and an ink supply mechanism of a printing apparatus main-body side.  FIG. 11  is a control block diagram of the printing apparatus  1 . 
         [0033]    A main-body side supply mechanism  301  includes a mechanism of supplying inks as fluids or liquids to the carrier  206  from the outside. The main-body side supply mechanism  301  is supported by a shaft  302  and a guide  303  supported on the chassis  201  to move reciprocally in an arrow direction C perpendicular to the moving direction B of the carrier  206 . 
         [0034]    A pump  304  serves as a pressure reducing unit for generating negative pressure to form an ink flow. The negative pressure is connected through a tube  305  and a negative pressure connection unit  306  to the main-body side supply mechanism  301 . 
         [0035]    A supply port  307  is connected with the ink tank  101 . By pushing-in the ink tank  101  toward the casing cover  901 , the ink tank  101  is coupled with the supply port  307  so that no ink leakage will occur. 
         [0036]    The supply port  307  is connected through a tube  308  and a negative pressure valve  309  to the main-body side supply mechanism  301 . A sub-ink tank  310  serves as a liquid chamber on the carrier  206  side. Negative pressure valves  311  and  312  are attached to the sub-ink tank  310 . 
         [0037]    A rotation driving device  313  moves reciprocally the main-body side supply mechanism  301  in the arrow direction C and drives the pump  304 . A driving direction of the pump  304  is not limited to a rotational direction of the rotation driving device  313 , and the main-body side supply mechanism  301  side is configured to transmit driving force only in one direction by a one-way clutch (not shown). 
         [0038]    A connection cam  316  is driven and rotated by the rotation driving device  313 . A cam surface of the connection cam  316  abuts on a side face  301   a  of the main-body side supply mechanism  301 , and rotates to move the main-body side supply mechanism  301  closer to the carrier  206 . Then, the negative pressure valve  309  and a part of the negative pressure connection unit  306  are moved to a position where they abut on a backside  206   a  of the carrier  206 . When a small-diameter part of the connection cam  316  rotates up to an initial position where the small-diameter part abuts on the side face  301   a , the main-body side supply mechanism  301  is moved away from the carrier  206  under a spring force, and the negative pressure valve  309  and the negative pressure connection unit  306  are separated from the backside  206   a  of the carrier  206 . The connection cam  316  and the spring constitute a moving unit. A disk  314  rotating integrally with the connection cam  316  includes a notch formed in a predetermined position. The notch is detected by a position sensor  315  to control a rotational angle phase of the connection cam  316 . 
         [0039]    The rotation driving device  313  and the position sensor  315  are connected to a control circuit  700  ( FIG. 11 ) via wiring lines (not shown) to be controlled by the circuit  700 . 
         [0040]      FIGS. 4A and 4B  are perspective and sectional diagrams of the negative pressure connection unit  306  and the negative pressure valve  309 . The configuration includes a cylinder  401 , a sealing member  404  made of an elastic material, and a spherical valve  402 . The spherical valve  402  is biased to abut on a slope surface within the cylinder  401  by a spring  403  and holds a pressure difference between a communication port  401   a  side bored in the cylinder  401  and a communication port  404   a  side bored in the sealing member  404  side with a contact surface. 
         [0041]    However, the negative pressure connection unit  306  does not include the spherical valve  402  and the spring  403  but includes only the cylinder  401  and the sealing member  404 . 
         [0042]    The pressure difference shows a relation, communication port  401   a  side pressure&gt;sealing member  404  side pressure, and is determined by setting of the spring  403 . When the pressure difference exceeds the retaining force of the spring  403 , the spherical valve  402  moves away from the slope surface in the cylinder  401  so that the communication port  401   a  side is communicated with the sealing member  404  side. 
         [0043]    When a sealing surface  404   c  of a rib  404   b  of the sealing member  404  abuts on a backside  206   a  of the carrier  206 , the rib  404   b  deforms to provide an air-tight seal. 
         [0044]      FIGS. 5A and 5B  are perspective and partial sectional diagrams illustrating the carrier  206 . The carrier  206  is guided to move reciprocally by bearings  502  and  503  guided by the shaft  207  and the guide  205  of the chassis  201 . 
         [0045]    An inkjet printing mechanism  504  is provided with an array of minute nozzles and includes an energy generating element for generating discharge pressure corresponding to each nozzle. The energy generating element is controlled to discharge ink from the corresponding nozzle based on a control signal sent from the control circuit  700  via a wiring line (not shown). 
         [0046]    The carrier  206  includes a negative pressure port  505 , an ink supply port  506 , and holes  507  and  508  for adjusting a position with positioning bosses  317  and  318  of the main-body side supply mechanism  301 . 
         [0047]    A negative pressure valve  509  controls a flow rate of an ink from a sub-tank  310  into an ink buffer chamber  510  of the inkjet printing mechanism  504  and is connected to the ink buffer chamber  510  through the communication port  511 . 
         [0048]    A configuration of the negative pressure valves  309 ,  311 ,  312 , and  509  is similar to that of  FIGS. 4A and 4B  and their characteristics can be changed by a spring. 
         [0049]      FIGS. 6A and 6B  are plan and partial sectional diagrams of the printing apparatus  1 . 
         [0050]    Each of  FIGS. 6A and 6B  illustrates the carrier  206  that reciprocates in the arrow direction B of  FIG. 2 , and the inkjet printing mechanism  504  performs printing on the print sheet  906 . 
         [0051]    When the inkjet printing mechanism  504  consumes the ink in the ink buffer chamber  510 , pressure within the ink buffer chamber  510  becomes negative. When the negative pressure reaches a certain value, a spherical valve  509   a  of the negative pressure valve  509  compresses a spring  509   b  to make an opening, thereby supplying an ink from the sub-tank  310  into the ink buffer chamber  510 . 
         [0052]    When the ink of the sub-tank  310  is reduced to produce negative pressure therein, and the negative pressure reaches a certain value, a spherical valve  312   a  of the negative pressure valve  312  opens to cause an atmosphere to flow in. When flowing-in of the atmosphere reaches a certain extent, a spring  312   b  of the negative pressure valve  312  closes the spherical valve  312   a . The negative pressure is maintained in the sub-tank  310  and no ink leakage occurs. The negative pressure valve  311  is not opened by the negative pressure on the sub-tank  310  side. Accordingly, no ink leakage occurs from this valve. 
         [0053]      FIGS. 7A and 7B  are plan and partial sectional diagrams of the printing apparatus  1 . Each of  FIGS. 7A and 7B  illustrates the negative pressure connection unit  306  and the negative pressure valve  309  that abut on the backside  206   a  of the carrier  206  to respectively connect to the negative pressure port  505  and the ink supply port  506 . If the carrier  206  is stopped in a predetermined position, the main-body side supply mechanism  301  is moved to the carrier  206  side by rotation of the connection cam  316 . The positioning bosses  317  and  318  of the main-body side supply mechanism  301  are engaged with the positioning holes  507  and  508  to position the main-body side supply mechanism  301  and the carrier  206  relative to each other. When the main-body side supply mechanism  301  is further moved, the negative pressure connection unit  306  and the negative pressure valve  309  respectively connect to the negative pressure port  505  and the ink supply port  506 . 
         [0054]    Alternatively, the ink supply port  506  may be moved to connect to the negative pressure valve  309 . 
         [0055]    In this state, the pump  304  is operated to generate negative pressure that is higher than presumed negative pressure in the sub-tank  310 , and applies negative pressure to the negative pressure valve  311  via the negative pressure connection unit  306 . Because of this negative pressure, a spring  311   b  of the negative pressure valve  311  loses out to negative pressure of the negative pressure connection unit  306  side so that a spherical valve  311   a  is opened, thereby increasing negative pressure in the sub-tank  310 . 
         [0056]    When the negative pressure of the sub-tank  310  is increased, the negative pressure causes a spherical valve  312   a  of the negative pressure valve  312  to compress a spring  312   b  to make an opening. That is, the negative pressure valve  312  is opened because pressure of an opposite side is smaller than the ink supply port  506  side of the negative pressure valve  312  by a predetermined or more than a predetermined amount. Further, negative pressure applied from the opened negative pressure valve  312  causes a spherical valve  309   a  of the negative pressure valve  309  to compress a spring  309   b  to make an opening. That is, the negative pressure valve  309  is opened because pressure of an opposite side is larger than an opening  404   d  side of the negative pressure valve  309  by a predetermined or more than a predetermined amount. As a result, the ink tank  101  is connected to the sub-tank  310  in the negative pressure state, and ink flows from the ink tank  101  into the sub-tank  310 . 
         [0057]    In this case, on the inkjet printing mechanism  504  side, the negative pressure valve  509  serves as a check valve that prevents reverse flowing of the ink or flowing-in of air from the nozzles of the inkjet printing mechanism  504 . 
         [0058]    According to the exemplary embodiment, a path of fluids from the supply port  307  connected to the ink tank  101  through the tube  308  to the negative pressure valve  309  corresponds to a first flow path. A path of fluids from the ink supply port  506  through the negative pressure valve  312  to the sub-tank  310  corresponds to a second flow path. The negative pressure of the sub-tank  310  opens the negative pressure valves  312  and  309  to cause the first and second flow paths to communicate with each other. Thus, the connection cam  316  and the pump  304  constitute a flow path connecting device. The connection cam  316  interconnects or separates the negative pressure valve  309  at the end of the first flow path and the supply port  307  at the end of the second flow path from each other. The pump  304  opens the negative pressure valves  312  and  309  to cause the first and second flow paths to communicate with each other. 
         [0059]    When the predetermined amount of ink is supplied to the sub-tank  310 , the main-body side supply mechanism  301  is separated from the carrier  206  side by rotation of the connection cam  316  to move to positions illustrated in  FIGS. 6A and 6B . 
         [0060]    A phenomenon of ink scattering is observed when the sealing member  404  of the negative pressure valve  309  is separated from the backside  206   a  of the carrier  206  during a separation operation of the main-body side supply mechanism  301  from the carrier  206 . As the ink flows through the negative pressure valve  309 , the ink remains around the communication port  404   a  and scatters in association with the separation operation. A space of a predetermined volume is present between the opening  404   d  of the sealing member  404  of the negative pressure valve  309  and the ink supply port  506  of the backside  206   a  of the carrier  206  and the ink scatters to the space during the separation. 
         [0061]    The scattered ink contaminates the print sheet  906 . Moreover, an operation of each unit becomes unstable if the scattered ink is fixed. 
         [0062]    The inventors have found out by experiment that almost no ink scattering occurs if the relative speed of the negative pressure valve  309  and the backside  206   a  of the carrier  206  is equal to or less than a predetermined speed at the time that the valve  309  and the carrier  206  are separated. 
         [0063]    The inventors have also found out that the speed needs to be equal to or less than the above relative speed only within a predetermined distance from an abutting position and the speed can be increased without problems outside the predetermined distance. 
         [0064]      FIGS. 1A and 1B  illustrate the ink behavior when the sealing member  404  of the negative pressure valve  309  is separated from the abutting backside  206   a  of the carrier  206 .  FIG. 1A  illustrating a case in which a separation speed is 20 mm/second or less and  FIG. 1B  illustrating a case in which a separation speed is higher than 20 mm/second. 
         [0065]    According to the exemplary embodiment, as connection is made in a horizontal direction, the ink left around the communication port  404   a  side is collected in the lower side of the sealing member  404  under the influence of gravity. 
         [0066]    In the case of separation at the speed of 20 mm/second and less, the ink collected in the lower side of the sealing member  404  is pulled to both sides while forming a bridge  601  between the sealing member  404  and the backside  206   a  of the carrier  206 . When the bridge is cut off, almost all of the ink is sucked by either side and thus little ink scattering occurs. 
         [0067]    In the case of separation at the speed higher than 20 mm/second, the ink collected in the lower side of the sealing member  404  is also pulled to both sides while forming a bridge between the sealing member  404  and the backside  206   a  of the carrier  206 . However, in this case, since the separation speed is high, a bridge cutoff state is unstable, and ink droplets  602  which are not sucked to neither side are left and scatter. 
         [0068]    The inventors have confirmed that the ink bridge is cut off when a distance (separation distance) between the sealing member  404  and the backside  206   a  of the carrier  206  is approximately 4 mm according to the exemplary embodiment. 
         [0069]      FIGS. 8A and 8B  illustrate an example of speed control devised based on the experiment results. According to the illustrated example, the speed control is performed to prevent scattering of ink droplets when the negative pressure valve  309  is separated from the backside  206   a  of the carrier  206 . FIG.  8 A is a graph illustrating the relation between separation distance and speed. 
         [0070]    When the separation distance is approximately 4 mm or less after the separation starts, the moving speed of the negative pressure valve  309  is controlled to be 20 mm/second or less. When the separation distance exceeds approximately 4 mm, no ink scatters. Accordingly, the negative pressure valve  309  can be moved at a speed higher than 20 mm/seconds. According to the exemplary embodiment, the speed is accelerated up to 50 mm/second. 
         [0071]    In the graph labeled speed  1  in  FIG. 8A , the speed of the negative pressure valve  309  is increased to 20 mm/second before a separation distance reaches 4 mm. The negative pressure valve  309  is moved at a constant speed of 20 mm/second until the separation distance reaches 4 mm. When the separation distance exceeds 4 mm, the speed is increased to 50 mm/second. 
         [0072]    In the graph of a speed  2 , the speed of the negative pressure valve  309  is increased under constant acceleration so that the speed reaches 20 mm/second when the separation distance reaches approximately 4 mm. When the separation speed exceeds 4 mm, the speed is increased up to 50 mm/second under higher acceleration. No ink scattering was observed when control was performed at both the speeds  1  and  2 . 
         [0073]    The ink examined according to the exemplary embodiment has a normal viscosity of 3.3 (mPa·/S) at a normal temperature and surface tension of 31 (mN/m). In a low-temperature environment, the viscosity and the surface tension increase by 1.5 times. However, no change occurred in separation conditions. Thus, similar effects can be achieved in fluids whose viscosity is 4 mPa/seconds or less. Similar effects can also be achieved in fluids whose surface tension is 40 mN/m or less. 
         [0074]    The sealing member  404  has a diameter of 5.5 mm as normal. However, due to variations of the components of the device, no change in separation conditions was observed up to about 6 mm. Accordingly, similar effects can be achieved if a diameter of a sealing surface of the sealing member  404  is 6 mm or less. 
         [0075]    For the sake of brevity, the exemplary embodiment has been described in term of one color. The exemplary embodiment can also be applied to multiple colors without any problems. In that case, however, when a diameter of the sealing member  404  exceeds approximately 6 mm, the size of the carrier may have to increase. 
         [0076]      FIG. 8B  is a chart collectively illustrating operations of each element with respect to a rotational angle of the connection cam  316 . The operations of the exemplary embodiment are completed by one rotation of the connection cam  316 . 
         [0077]    In  FIG. 8B , when an ink supply operation is started, the control circuit  700  rotates the connection cam  316  by the rotation driving device  313 . When the connection cam  316  forms a rotational angle of 10°, a signal of the position sensor  315  is switched from a low level (L) to a high level (H). At a rotational angle of 20°, the connection cam  316  starts movement of the main-body side supply mechanism  301 . At a rotational angle of 70°, as illustrated in  FIGS. 7A and 7B , the negative pressure connection unit  306  and the negative pressure valve  309  are respectively connected to the negative pressure port  505  and the ink supply port  506 , and the main-body side supply mechanism  301  stops. At a rotational angle of 90°, the control circuit  700  drives the pump  304  by the rotation driving device  313  to supply the ink from the ink tank  101  to the sub-tank  310 . At a rotational angle of 220°, the pump  304  is stopped and the ink supplying is finished. From a rotational angle of 240°, the connection cam  316  separates the main-body side supply mechanism  301  from the carrier  206 . During a predetermined period from rotational angles of 240° to 300° of the connection cam  316 , the main-body side supply mechanism  301  moves at a speed of 20 mm/seconds. When the connection cam  316  forms a rotational angle of 300°, a distance (separation distance) between the sealing member  404  and the backside  206   a  of the carrier  206  is 4 mm. Between rotational angles of 300° and 340° after the predetermined period lapses, the main-body side supply mechanism  301  moves at a speed of 50 mm/seconds. At a rotational angle of 350°, the signal of the position sensor  315  is switched from H to L. The control circuit  700  controls the rotation driving device  313  to stop the connection cam  316  in response to the signal of the position sensor  315 . 
         [0078]    According to the exemplary embodiment, the moving speed of the main-body side supply mechanism  301  is controlled based on the shape of the cam. However, the main-body side supply mechanism  301  may be driven and moved by the motor and the moving speed may be controlled by regulating a rotational speed of the motor. That is, during a predetermined period until a distance (separation distance) between the sealing member  404  and the backside  206   a  of the carrier  206  becomes 4 mm, the motor is driven at a first rotational speed. After a lapse of the predetermined period, the motor is driven at a second rotational speed that is higher than the first rotational speed. 
         [0079]    While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all modifications, equivalent structures, and functions. 
         [0080]    This application claims priority from Japanese Patent Application No. 2007-175294 filed Jul. 3, 2007, which is hereby incorporated by reference herein in its entirety.