Abstract:
A printing apparatus that selectively couples a device to a printer carriage is provided. The printing apparatus includes a printer carriage and an intervening mechanism. The printer carriage is movable back and forth to selectively retrieve the device from and return the device to a position where the device can be parked detached from the carriage. The carriage is arranged to selectively move back and forth relative to the device while the device is detached from the carriage and in unison with the device while the device is attached to the carriage. The intervening mechanism and the carriage have respective surfaces that engage as they meet each other to allow the carriage to move past the intervening mechanism.

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to selectively coupling a device, such as an optical measurement device, to a carriage, such as a printer carriage while moving past an intervening mechanism, such as an activator for a cutting tool. 
     BACKGROUND OF THE INVENTION 
     Referring to  FIG. 1 , one example of a wide format ink jet printer  10  includes right and left side housings  72 ,  74 , and is supported by a pair of legs  76 . The right housing  72 , shown in  FIG. 1  with a display and keypad for operator input and control, encloses various electrical and mechanical components related to the operation of the printer  10 . The left housing  74  encloses ink reservoirs  86  which feed ink to the ink-jet printheads  82  via plastic conduits  84 , which run between each ink-jet printhead  82  and each ink reservoir  86 . In some printer embodiments, no separate ink reservoirs  86  or tubing  84  is provided, and printing is performed with ink reservoirs integral to the printheads. Housing  72  or  74  may also include a maintenance station to clean and cap the printheads as needed. A printing region extends all or part of the way between the two housings  72  and  74 . 
     Either a roll of continuous print media (not shown) is mounted to a roller on the rear of the printer  10  to enable a continuous supply of paper to be provided to the printer  10  or individual sheets of paper (not shown) are fed into the printer  10 . In the case of roll-fed media, the media is cut after printing an image. A platen  78  forms a horizontal surface which supports the print media, and printing is performed by selective deposition of ink droplets onto the paper. During operation, a continuous supply of paper is guided from the roll of paper mounted to the rear of the printer  10  across the platen  78  by a plurality of rollers (not shown) which are spaced along the platen  78 . 
     Print carriage  12  is supported above the platen  78  by primary guide rail  70 . The print carriage  12  includes a plurality of ink-jet printheads  82  mounted therein. In the example shown in  FIG. 1 , four printheads  82  are mounted on the print carriage  12 , although it is contemplated that any number ink-jet printheads  82  can be provided. A motor and a drive belt mechanism (not shown) are used to drive the print carriage  12  back and forth along the primary guide rail  70 , as denoted by bidirectional arrow  80 . 
     For high quality printing, it is sometimes necessary to monitor the characteristics of the printed image. For example, a spectrophotometer may be used to measure the colors being provided by the printed ink, relative to the intended colors. If it is found that the colors are outside the desired range, then adjustments may be made. Such adjustments may include cleaning of the printhead, adjusting the drop size ejected by the printhead, or adjusting the number of droplets ejected for providing a particular desired color, for example. 
     When permanently affixing an optical measurement device, such as a spectrophotometer to a printer carriage, the mass of the carriage is significantly increased when the device is mounted to it, thereby requiring more expensive rail and motor systems in the printer to compensate for the increased mass, particularly for high throughput printing requiring high velocity and acceleration of the printhead carriage. Also, for the case of an inkjet printing system, the optical measurement device is unable to make precise measurements when it is contaminated with ink mist and it can be difficult to shield the device adequately from the ink mist when it is mounted so closely to the source of the ink mist generation (e.g. when the optical device is mounted next to the printheads during printing). 
     Accordingly, there is a need in the art for an apparatus and method for selectively coupling a device, such as an optical measurement device, to a carriage, such as a printer carriage, as needed so that the optical measurement device does not spend its life span mounted to the carriage. In doing so, it may be necessary to move components of the printing system in a manner that gives the carriage a path to reach the optical measurement device even through there may be an intervening mechanism, such as an activation mechanism for a media cutting tool, in a path between the printing region of the carriage and the optical measurement device in its parked position. 
     SUMMARY OF THE INVENTION 
     Therefore, aspects of the invention are directed to providing an apparatus and method for selectively coupling a device, such as an optical measurement device, to a carriage, such as printer carriage, after moving past an intervening mechanism, such as a cutter activation mechanism. 
     According to one aspect of the invention, a printing apparatus that selectively couples a device to a printer carriage is provided. The printing apparatus includes a printer carriage and an intervening mechanism. The printer carriage is movable back and forth to selectively retrieve the device from and return the device to a position where the device can be parked detached from the carriage. The carriage is arranged to selectively move back and forth relative to the device while the device is detached from the carriage and in unison with the device while the device is attached to the carriage. The intervening mechanism and the carriage have respective surfaces that engage as they meet each other to allow the carriage to move past the intervening mechanism. 
     According to another aspect of the invention, a method of selectively coupling a device to a printer carriage includes providing a carriage moveable along a travel path including a printing region, the carriage including a printhead and a media cutter; providing a device located at a parked position; providing a media cutter actuation mechanism deployed along the travel path between the printing region and the parked position of the device; optionally actuating the media cutter by causing the carriage to engage the media cutter actuation mechanism, the carriage then returning to the printing region of the travel path with the media cutter being actuated, or optionally causing the carriage to move past the media cutter actuation mechanism and couple to the device; the carriage then returning to the printing region of the travel path without the media cutter being actuated. 
     According to one aspect of an embodiment of the invention, one of the printer carriage and the optical measurement device includes a hook and the other of the printer carriage and the optical measurement device includes a latch mechanism. The hook connects with the latch mechanism to couple the optical measurement device to the printer carriage. The optical measurement device moves with the printer carriage in the printer when the optical measurement device is coupled to the printer carriage. The latch mechanism is adapted to disengage from the hook when the optical measurement device is returned to a parking position. 
     According to another aspect of an embodiment of the invention, the printer frame includes a latch retractor mechanism that holds the latch mechanism in a retracted state when the optical measurement device is in a parking position. The printer carriage couples with the optical measurement device when the hook mechanism engages the latch mechanism such that the latch mechanism is released from the latch retractor mechanism and extends to an unretracted state to connect with the hook. When the printer carriage returns the optical measurement device to a parking position, the hook facilitates engagement of the latch mechanism with the latch retractor mechanism such that the latch mechanism returns to a retracted state that is held by the latch retractor mechanism. With the latch mechanism retracted, the hook is disengaged such that the printer carriage is able to move within the printer without being coupled to the optical measurement device. 
     According to an aspect of another embodiment the invention, the printer includes a printing region, a parking position for a selectively connectable optical measurement device, and a cutter activation mechanism which is located between the parking position and the printing region. The printer carriage is selectively connectable with the optical measurement device, and includes a cutting device that may be activated by the cutter activator. The cutting device can include a tab extending from a yoke that holds the axle for the cutting wheel. As the printer carriage moves from the printing region towards the cutter activator, the cutter activator engages one side of the tab to activate the cutting wheel for a cutting operation within the printer. After engaging the tab, if the printer carriage is moved further toward the parking region, the cutter activator is moved aside by the tab to enable the printer carriage to move past the cutter activator to allow the carriage to couple with the optical measurement device. After connecting with the optical measurement device, the printer carriage is moved back toward the printing region for optical measurements. On the way to the printing region, the tab engages the other side of the cutter activator to deactivate the cutting wheel. The tab then causes the cutter activator to move away from the tab to enable the printer carriage to move past the cutter activation mechanism within the printer. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other objects of the invention will become more fully apparent from the following description and appended claims taken in conjunction with the following drawings, where like reference numbers indicate identical or functionally similar elements. 
         FIG. 1  is a front view of a conventional wide format ink jet printer. 
         FIG. 2  is a perspective view of a portion of a wide format ink jet printer according to aspects of embodiments of the invention; 
         FIG. 3A  is perspective view of a cutting device in the ink jet printer of  FIG. 1  according to an aspect of embodiment of the invention; 
         FIG. 3B  is a perspective view of the inside of the cutting device of  FIG. 3A ; 
         FIGS. 4-6  are perspective front views of the ink jet printer of  FIG. 2  showing a portion of the printer carriage as a tab on the cutting device of  FIG. 3A-B  engages a cutter activator to activate a cutting wheel; 
         FIG. 7  is a perspective front view of the ink jet printer of  FIG. 2  as a tab on the cutting device pushes the cutter activator out of the way; 
         FIG. 8  is a perspective view of the inside of the casing of the cutter activator on the printer carriage; 
         FIGS. 9-10  are perspective views of a spectrophotometer in the ink jet printer of  FIG. 1  according to an aspect of an embodiment the invention; 
         FIG. 11  is a perspective view of the underside of the spectrophotometer of  FIGS. 8-9 ; 
         FIG. 12  is a perspective rear view of the ink jet printer of  FIG. 1  as the printer carriage approaches the spectrophotometer; 
         FIG. 13  is a perspective rear view of the ink jet printer of  FIG. 1  as the printer carriage hook contacts the spectrophotometer; 
         FIG. 14  is a perspective rear view of the ink jet printer of  FIG. 1  as a printer carriage hook pushes the spectrophotometer; 
         FIG. 15  is a perspective rear view of the ink jet printer of  FIG. 1  as a latch closes to couple the spectrophotometer to the printer carriage; 
         FIGS. 16-18  are perspective rear views of the ink jet printer of  FIG. 1  as the printer carriage pulls the spectrophotometer away from its parked position; 
         FIG. 19-21  are perspective front views of the ink jet printer of  FIG. 1  as the printer carriage moves toward the printing region after coupling with the spectrophotometer; 
         FIG. 22  is a perspective view of the printer carriage bypassing the cutter activator after the printer carriage couples with the spectrophotometer; and 
         FIG. 23-25  are perspective rear views of the ink jet printer of  FIG. 1  as the printer carriage returns the spectrophotometer to its parked position. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention will be directed in particular to elements forming part of, or cooperating more directly with, apparatus and methods in accordance with the present invention. It is to be understood that elements not specifically shown or described may take various forms well known to those skilled in the art. 
     Referring to  FIG. 2 , an example of a portion of wide format ink jet printer  10  is shown including a printer carriage  12  and a cutting device  14  that is used for cutting paper in the printer. Cutting device  14  is mounted on printer carriage  12 , for example, by screws. Referring to  FIG. 1 , during printing, printheads  82  eject ink to form an image as the carriage  12  is scanned back and forth along scan direction arrow, with media being advanced between successive scans. The cutting blade of cutting device  14  needs to be withdrawn during printing, or the image would be sliced into strips. As described in more detail below with reference to  FIGS. 3A-3B , cutting device  14  includes a tab  20  that moves cutting wheel  16  up into a withdrawn position, or down into a cutting position, depending on the position of tab  20 . In the present example, a cutter activator (described below) is located in left housing  74 , while a cutter deactivator is located in right housing  72 . During normal printing, the printing carriage does not travel far enough out of the printing region toward the left housing  74  or to the right housing  72  for the tab  20  of cutting device  14  to engage either the cutter activator or the cutter deactivator. However, after the image has been printed and is ready to be separated from the media supply, the carriage  12  moves to the left housing  74  in order to activate the cutting device  14 . 
     In the example shown in  FIGS. 3A-3B , the cutting device  14  is formed of a front casing  13   a  and a rear casing  13   b  that enclose a cutting wheel  16  having an axle that is mounted on yoke  18 . Yoke  18  has a tab  20  extending through slot  15  in front casing  13   a . When tab  20  is moved to the upper portion of slot  15 , cutting wheel  16  is withdrawn, and when tab  20  is moved to the lower position of slot  15 , cutting wheel  16  is extended so that the cutting device  14  is activated. An upper spring  22  can be provided that enables the cutting wheel  16  to snap into position and a lower spring  24  can be provided that forces the cutting wheel  16  against the cutting bar (not shown) in the printer  10 . Casing  13   a ,  13   b  can include a detent (for example at the lower horizontal or “down” portion of slot  15 ) that holds the yoke  18  in position until the tab  20  is moved to the other position. Yoke  18  can have an arm  25  that enables the cutting wheel  16  to be gently moved into engagement with the cutting bar, so that the cutting wheel  16  does not nick the cutting bar. As shown in  FIG. 4-6 , as the printer carriage  12  moves towards the left (in the view of  FIG. 1 ) toward left housing  74 , a cutter activator  28  attached to the printer framework engages tab  20  on cutting device  14  and continues to push tab  20  until the tab  20  moves into the down position of slot  15 , pushing yoke  18  down to extend cutting wheel  16  so that cutting device  14  is activated. If the printer carriage  12  is now moved into the printing region where the media is located, the activated cutting device  14  cuts the media between the cutting wheel  16  and the cutting bar (not shown). The carriage  12  can proceed to the right housing  72  to park the printheads  82  in a maintenance station in a home position (not shown). As the carriage  12  moves toward the home position in right housing  72 , a cutter deactivator (not shown) is engaged by tab  20  so that tab  20  is moved into the up position in inclined slot  15 , thus raising cutting wheel  16  and deactivating the cutting device  14 . For the next printing job, as carriage  12  exits the home position and moves into the printing region, the cutting device remains deactivated, so that printing can occur without simultaneously cutting the media. Occasionally it is desired to measure the color characteristics of a printed image. In an embodiment of the present invention, an optical measurement device such as a spectrophotometer is parked in a position at the far left side of left housing  74 . The movement of the spectrophotometer is constrained to be along the same direction as the carriage motion, so that if the carriage and spectrophotometer are coupled together, the carriage can move the spectrophotometer back and forth across the printing region. The parked position of the spectrophotometer, far from the printing region, provides some protection against ink mist contamination of the optics of the spectrophotometer. In this configuration, cutter activator  28  is between the printing region and the spectrophotometer. An object of the present invention is to enable the printing carriage  12  to bypass cutter activator  28 , couple with the spectrophotometer, and bring the spectrophotometer into the printing region for optical measurements, without having cutting device  14  activated in the printing region. Thus the media is not cut as the optical measurements are being made. 
     As shown in  FIG. 7 , in order to couple with the optical measurement device, the printer carriage  12  continues moving to the opposite side of cutter activator  28 . To do this, tab  20  pushes the cutter activator  28  up and out of the way. Specifically, the cutter activator  28  can have internal springs  27 ,  29 , as shown in  FIG. 8 , that have an appropriate stiffness or strength (i.e., spring constant) so as to prevent the cutter activator  28  from being displaced when engaging the tab  20  to activate the cutting device  14 . However, when tab  20  is at the end of travel in slot  15 , as in  FIG. 7 , continued movement of printer carriage  12  (and consequently tab  20 ) to the left is able to overcome the stiffness of spring  27 , so that cutter activator  28  can be pushed out of the way until it is bypassed by tab  20 . It should be understood that when a cutter activator  28  is disposed in the printer  10 , the printer carriage  12  may move past the cutter activator  28  to reach the optical measurement device, as explained above, however, the present invention is not limited to use in a printer that has a cutter activator. 
     Once tab  20  has bypassed cutter activator  28 , the printer carriage  12  is ready to be coupled with the optical measurement device, such as the spectrophotometer  26  shown in  FIGS. 9-11 . A bracket  30  slidably connects the spectrophotometer  26  to the printer  10  frame. A latch  36  attached to the bracket  30  is used to connect the spectrophotometer  26  to the printer carriage  12  as described below. The underside of the spectrophotometer  26  includes a sensor assembly  32  (including a light emitter, a sensor and associated optics) that is used to measure color. A cable  34  communicates data from the spectrophotometer  26  to the printer controller. 
     Referring now to the rear view shown in  FIG. 12 , when the spectrophotometer  26  is in its parked position, the latch  36  is retracted within latch housing  38 , and is held in the retracted state by latch retractor  42 . Latch  36  includes a latching portion  37  and an inclined contact portion  39  having a rear edge  41  (shown in  FIG. 14 ). Latch retractor  42  includes an inclined contact portion  43  and a catch  45 , and is mounted on an latch retractor housing  44  that is attached to the printer frame with a bracket  46 . Spring  47  that is disposed in the latch retractor housing  44  pushes on the latch retractor  42  in a rearward direction  35 , while also allowing the latch retractor  42  to be pushed in an opposite direction as described below. In the views of  FIGS. 12 and 13 , the catch  45  of latch retractor  42  is holding rear edge  41  of inclined contact portion  39  so that latch  36  is held in the retracted position. 
     When the printer carriage  12  approaches the spectrophotometer  26 , a printer carriage hook  48  extending from the printer carriage  12  pushes against the spectrophotometer  26  further toward the left side of housing  74  in the front view of  FIG. 1 , or toward the right as shown in the rear view of  FIG. 13 . As the printer carriage hook  48  pushes the spectrophotometer  26  away from its parked position, the rear edge  41  of inclined contact portion  39  of latch  36  is pushed away from the catch  45  of the latch retractor  42 , as shown in  FIG. 14 . A spring (not shown) in the latch  36  then snaps the latch  36  into an unretracted position, so that the latching portion  37  captures hook  48  as shown in  FIG. 15 . A stopper (not shown) may be provided to prevent the latch  36  from extending too far. As the printer carriage  12  is then moved in the opposite direction toward the printing region, the printer carriage hook  48  then pulls the spectrophotometer  26  towards the printing region and the inclined contact portion  39  of latch  36  engages the inclined contact portion  43  of latch retractor  42 , as shown in  FIG. 16 . The purpose of the inclined contact portions  39  and  43  is to provide a motion in a direction perpendicular to carriage direction motion  80 . As the printer carriage hook  48  continues to pull the spectrophotometer  26  towards the printing region, the inclined contact portion  39  of latch  36  pushes the inclined contact portion  43  of latch retractor  42 , so that the latch retractor  42  slides up in a direction opposite rearward direction  35  and out of the way, as shown in  FIG. 17 . Assisted by spring  47  in the latch retractor housing  44 , the latch retractor  42  then snaps along rearward direction  35  into its normal position, as shown in  FIG. 18 . 
     At this point, the cutting wheel  16  is still extended and must be raised before the printhead carriage  12  and the spectrophotometer  26  connected to it move into the printing region for making optical measurements. As shown in  FIG. 19 , as the printer carriage  12  moves towards the printing region, tab  20  engages the back-side of the cutter activator  28 . As a result, tab  20  is moved up along inclined slot  15  to deactivate the cutting wheel  16 , as shown in  FIGS. 20-21 . When the tab  20  has reached the end of slot  15 , it can move no further, so as the printer carriage  12  continues to move toward the printing region, spring  29  is compressed ( FIG. 8 ) and cutter activator  28  is moved aside so that tab  20  can bypass it, as shown in  FIG. 22 . 
     When the spectrophotometer  26  is coupled to the printer carriage  12 , as described above, the spectrophotometer  26  may move from side-to-side along direction  80  in the printer together with the printer carriage  12  and perform its optical measurements. When the optical measurement device completes its measurements, the printer carriage  12  may return the optical measurement device to its parked position. Specifically, the printer carriage hook  48  on the printer carriage  12  pushes the spectrophotometer  26  back to the left housing  74  of printer  10  until the latch  36  engages the latch retractor  42 , as shown in  FIG. 23 . The latch  36  then begins to retract as the inclined contact portion  39  of the latch  36  slides along the inclined contact portion  43  of the latch retractor  42 , as shown in  FIGS. 23 and 24 . Comparing  FIG. 23  with  FIG. 17 , note that in the latch retracting step corresponding to  FIG. 23 , opposite surfaces of inclined contact portions  39  and  43  are in contact relative to the latch engaging step corresponding to  FIG. 17 . The printer carriage hook  48  continues pushing the spectrophotometer  26  until the rear edge  41  of the inclined contact portion  39  of latch  36  is held back in the retracted position by catch  45  of the latch retractor  42 , as shown in  FIGS. 23-25 . The printer carriage  12  is then free to move back to the printing region of the printer  10  so it can resume its printing operations. During the approach of the printer carriage  12  toward uncoupling the spectrophotometer, the cutting device  14  was again activated, but as the printer carriage moved back toward the printing region, the cutting device is again deactivated as described above in relation to the coupling of the spectrophotometer  26  to the printer carriage  12 . 
     The cutting device  14  is a kind of tool having an activated state (e.g. blade in the cutting position) and a deactivated state (e.g. withdrawn blade) and can be a cutter, such as a blade, a perforator, or a cutting wheel. Alternatively, the cutting device  14  may be replaced by other kinds of devices having a mechanically activated state and a deactivated state, such as a light shutter. 
     The cutter activator  28  is a kind of intervening mechanism that activates and/or deactivates the tool and is disposed in the path between the printing region and the parked position of the device that may be selectively connectable to the printer carriage  12 . 
     The spectrophotometer  26  is a kind of device to which the printer carriage  12  may be selectively connected to or disconnected from. In place of the spectrophotometer  26  as the device, the following examples may serve as exemplary selectively connectable devices: a spectrometer, a photometer, a densitometer, an image scanner a heater, a Hall effect sensor, and an ultraviolet light source. 
     The printer carriage  12  is a type of carriage and may include an inkjet print head. 
     It is understood that the present invention is not limited to the printer carriage being coupled with a particular type of device, such as a spectrophotometer. Rather, the printer carriage can be coupled with any type device having a latch and latch retractor as explained above. 
     It is further understood that the above-described embodiments are merely illustrative of the possible specific embodiments which may represent principles of the present invention. Other arrangements may be readily devised in accordance with these principles by those skilled in the art without departing from the scope of the invention. 
     PARTS LIST 
     
         
         
           
               10  printer 
               12  printer carriage 
               13  cutting device casing 
               14  cutting device 
               15  slot 
               16  cutting wheel 
               18  yoke 
               20  tab 
               22  upper spring 
               24  lower spring 
               25  arm 
               26  spectrophotometer 
               27  spring 
               28  cutter activator 
               29  spring 
               30  bracket 
               32  sensor assembly 
               34  cable 
               35  rearward direction 
               36  latch 
               37  latching portion 
               38  latch housing 
               39  inclined contact portion of latch 
               41  rear edge of inclined contact portion of latch 
               42  latch retractor 
               43  inclined contact portion of latch retractor 
               44  latch retractor housing 
               45  latch retractor catch 
               46  bracket 
               47  spring 
               48  printer carriage hook 
               70  guide rail 
               72  right housing 
               74  left housing 
               76  legs 
               78  platen 
               80  bidirectional arrow 
               82  printhead 
               84  tubing 
               86  ink reservoirs