Abstract:
A replaceable ink delivery tube system for a large format ink jet printer includes four flexible ink delivery tubes arranged in parallel and each permanently connected at one end to a printhead connector and at the other end to an off-axis ink reservoir receiving connector which, when mounted in the printer, is accessible from the front side of the printer to insert and remove four separate ink reservoirs from the ink reservoir connector. Lockouts are provided at both the printhead connector and ink reservoir connector ends of the replaceable delivery tube system to ensure that only ink reservoirs and printheads of the correct type can be attached to the replaceable system. The replaceable ink delivery tube system enables rapid modification of a printer to accept either pigment based or dye-based inks and the lockouts prevent pigment based ink reservoirs and printheads from being connected to a dye-based ink replaceable tube system or vice versa. Although access to the rear side of the printer is required for replacement of the ink delivery tube system, the off-axis ink reservoirs and onboard printheads are all replaceable from the front side of the printer.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS, IF ANY 
     None. 
     BACKGROUND OF THE INVENTION AND PRIOR ART 
     The present invention relates to the art of computer driven printers, particularly, large format color ink jet printers. Printers of this type have a printhead carriage which is mounted for reciprocal movement on the printer in a direction orthogonal to the direction of movement of the paper or other medium on which printing is to take place through the printer. The printer carriage of a color printer typically has four removable electric or thermal ink jet printheads mounted thereon. Each of the printheads contains a supply of ink which, for large scale printers, is generally inadequate due to the large volumes of ink which are required as compared with the ink supply requirements of desk top printers. Consequently, various means have been proposed for continuously or periodically refilling the carriage-borne printheads with ink. These systems fall into two categories. The first comprises offboard or off-axis ink reservoirs which are continuously connected to the carriage-borne or onboard printheads by flexible tubes. The second comprises a “take a gulp” system in which the printhead carriage is periodically moved to one end of its path of travel where it is then connected with off-axis ink reservoirs to fill the onboard printheads. This “take a gulp” system is disclosed in Hewlett-Packard&#39;s Designjet 2000 printer referred to in U.S. patent application Ser. No. 08/805,861 filed Mar. 3, 1997 and published in European Patent Publication No.0863016 on Sep. 9, 1998. 
     Large format printers are expensive pieces of equipment which preferably should be capable of using different types of ink without significant modification of the printer. The different ink types may for convenience be broadly referred to as indoor ink and outdoor ink, meaning ink intended to be used for production of drawings, posters, and other printed material which may be displayed outdoors or indoors. Outdoor ink is pigment based, i.e. containing a plurality of discrete undissolved pigment particles suspended in a fluid carrier. Dye-based ink has a lower degree of optical density and permanence but is less expensive. Since pigment based inks and dye-based inks are incompatible with each other, a system is desired which enables the use of either type of ink in a printer without cross-contamination of the printer inks by each other. 
     Further, in color printers four separate colors of ink are usually employed comprising black and three primary or mid-primary colors such as cyan, magenta and yellow. In color ink printers provision must also be made to ensure that neither incorrect types of ink nor incorrect colors of ink can inadvertently be used in the system. 
     SUMMARY OF THE INVENTION 
     The present invention provides a replaceable ink delivery tube system for a large format printer comprising: 
     a) at least one flexible ink delivery tube; 
     b) a printhead connector affixed to an ink delivery end of said tube; and 
     c) an ink reservoir connector affixed to an ink supply end of said tube; said printhead connector and said ink reservoir connectors each having lockout means thereon to permit connection of said connectors only to preselected complementary mating ink reservoirs and printheads. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a large format printer in which the present invention is useful. 
     FIG. 2 is a top plan view of the printer with its cover removed to show the printhead carriage and ink tube guides and supports. 
     FIG. 3 is a front elevation view of the upper portion of the printer with cover removed to show the printhead carriage and attached printhead connector tubes. 
     FIG. 3A is a partial elevation view of the rear tube guide showing a tube clip affixed thereto. 
     FIG. 4 is a vertical cross-section through the relevant portions of the printer showing the relative position of the carriage, the tube guide system and the ink delivery tubes and carriage connector. 
     FIG. 5 is a front elevation view of the printhead connector, partly broken away, with a printhead carriage being shown in phantom. 
     FIG. 6 is a right side elevation view of the printhead connector, partly broken away, with a printhead carriage shown in phantom. 
     FIG. 6A is a partial right side elevation view like FIG. 6 of the printhead connector showing a resilient carriage connection tab. 
     FIG. 7 is a top plan view of the printhead connector showing printhead lockouts therein with portions of a printhead carriage shown in phantom. 
     FIG. 8 is a perspective view from below of a printhead showing a lockout tab configuration which mates with the cyan color slot of the printhead connector. 
     FIG. 9 is a front elevation view of the reservoir connector with one reservoir lockout removed. 
     FIG. 10 is a perspective of a lockout receivable in the reservoir connector having a fin configuration complementary with the fin configuration on an ink reservoir. 
     FIG. 11 is an elevation of the ink connection end of an ink reservoir having a fin configuration complementary with the fin configuration of the reservoir connector lockout of FIG.  10 . 
     FIG. 12 is a rear elevation view of the reservoir connector. 
     FIG. 13 is a left side elevation view of the reservoir connector, the right side view being a mirror image thereof. 
     FIG. 14 is a top plan view of the reservoir connector. 
     FIG. 15 is a vertical cross section of the reservoir connector showing a connector module resiliently mounted therein. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1 shows a large format printer  10  of the type which includes a transversely movable printhead carriage enclosed by a plastic or metal hinged cover  12  which extends over a generally horizontally extending platen  14  over which printed media is discharged. At the left side of the platen is a transparent hinged cover  16  which contains four removable ink reservoirs  20 ,  22 ,  24 ,  26  which, through a removable flexible tube arrangement to be described, supply ink to four inkjet printheads mounted on the moveable carriage. 
     In the plan view of FIG. 2 in which the carriage cover  12  has been removed, it is seen that the printhead carriage  30  is mounted on a pair of transversely extending slider rods or guides  32 ,  34  which in turn are rigidly affixed to the frame of the printer. Also rigidly affixed to the frame of the printer are a pair of tube guide support bridges  40 ,  42  from which front and rear tube guides  44 , 46  are suspended. The printhead carriage  30  has a pivotal printhead holddown cover  36  fastened by a latch  38  at the front side of the printer which securely holds four inkjet printheads, one of which is shown in FIG. 7 in place in stalls C, M, Y, B on the carriage. The front tube guide  44  is angled near the left bridge support  40  to provide clearance for opening the printhead cover when the carriage is slid to a position proximate the left side of the platen  14  so that the printhead holddown cover  36  can be easily opened for changing the printheads. 
     A replaceable ink delivery tube system described in more detail below conveys ink from the four separate ink reservoirs  20 ,  22 ,  24 ,  26  at the left side of the printer through four flexible ink tubes  50 ,  52 ,  54 ,  56  which extend from an ink reservoir connector  70  through the rear and front tube guides  44 ,  46  to a printhead connector  100  which is releasably affixed to the carriage  30 . 
     At the right side of the printer is a printhead service station  80  at which the printhead carriage  30  may be parked for servicing such as wiping, spitting or priming the printheads. 
     As seen in FIG. 3, each of the four ink reservoirs  20 ,  22 ,  24 ,  26  is easily accessible from the front of the printer when the reservoir cover  16  (seen in FIG. 1) is open so that the reservoirs can be easily removed to be refilled or replaced with new reservoirs. As is known in the art, three of the reservoirs each contain a different base color of ink such as cyan, magenta and yellow and the fourth reservoir contains black ink so that a high number of colors can be produced as desired during printing. FIG. 11 shows an ink connector  23 , an air connector  25  and an electrical connector  27  on the front end of an ink reservoir  20 . The other reservoirs are similarly constructed. 
     As shown in the cross-sectional view of FIG. 4, the front and rear tube guides  44 ,  46  are of channel configuration having a lower support surface which extends in a common horizontal plane for supporting the ink delivery tubes  50 ,  52 ,  54 ,  56  at all points with the exception of the reverse bend B (FIG. 2) in the tubes to the right of the printer carriage  30 . 
     The replaceable ink delivery tube system is broadly comprised of the four flexible ink delivery tubes  50 ,  52 ,  54 ,  56  which are all permanently connected at one end to the printhead connector  100  which is a relatively rigid plastic part best seen in FIGS. 4-7 and, at the other end, to the reservoir connector  70  which is another relatively rigid plastic part best seen in FIGS.  9  and  12 - 15 . The ink delivery tubes are preferably made of a linear low density polyethylene. A protective sheath  58  encloses the flexible ink tubes between their permanent connection to the printhead connector  100  and a rigid plastic tube clip  130  which fastens the ink tubes to the rear tube guide  46  at the location shown in FIG. 3A near the left side of the printer. The protective sheath  58  preferably includes wear resistant lubricious ribs  51 ,  53  on the top of the upper tube  50  and at the bottom of the lower tube  56  and ribs  55  on the sides of all four tubes  50 ,  52 ,  54 ,  56  which face the front and rear tube guides  44 ,  46 . The ribs  51 ,  53 ,  55  are preferably made from polypropylene containing about 5% aramid fibers and 20% polytetrafluoroethylene (TEFLON). The material of the sheath  58  is preferably a polypropylene and EPOM compound which is both flexible and fatigue resistant. The above combination of materials for the sheath and ribs has been found to be considerably more quiet than prior art flexible ink deleivery tube systems. 
     Apertures cut into the vertical wall of the rear tube guide  46  receive mating bayonet clips  132 ,  134  on the rear side of the tube clip  130  so that the tube clip may be slid to the right or the left to easily connect or disconnect the clip  130  from the rear tube guide  46 . 
     The printhead connector  100  comprises a plastic part which is rigid as compared with the flexible ink delivery tubes and sheath and extends from the left end of the ink delivery tubes guided in front guide  44  to which the connector  100  is permanently affixed downwardly and thence towards the front of the printer and again downwardly and thence to the right where it is affixed to the printhead carriage as seen in FIGS. 4-6. The printhead connector  100  has four ink tube channels therein respectively guiding one each of the ink delivery tubes  50 ,  52 ,  54 ,  56  in a curved plane until the ink delivery tubes each terminate in an ink delivery connector end  110 ,  112 ,  114 ,  116  which extends generally upwardly for engagement with one of four separate printheads mounted on the carriage  30 . The ink delivery connector ends  110 ,  112 ,  114 ,  116  are resilient to provide slight lateral movement to facilitate connection and have metal collars  111 ,  113 ,  115 ,  117  which are affixed thereto, the connectors comprising female connectors which mate with the complementary configured male connectors on each of the printheads to provide a flexible but fluid tight connection as the printheads are inserted vertically downwardly into the stalls C, M, Y, B on the carriage  30 . The printhead connector is easily affixed to and removed from the carriage by squeezing a pair of resilient finger tabs  102 ,  104 , as seen in FIGS. 5 and 7 to disengage apertures  106  in the free ends of the tabs  102 ,  104  from mating projections on the sides of the carriage  30  when the printhead connector  100  is to be detached from the carriage. Attachment of the printhead connector to the carriage is made by horizontally sliding the printhead connector  100  toward the rear of the printer so that a guide  108  on the connector  100  is received in a mating guide (not shown) on the carriage  30  as the printhead connector is moved toward the rear of the printer, the resilient finger tabs  102 ,  104  automatically bending outwardly due to camming edges on the ends thereof which engage complementary camming edges on the projections on the printhead carriage which are then received in the apertures  106  in the resilient finger tabs as seen in FIG.  6 A. 
     Referring now to FIGS. 7 and 8, four printheads  140  (one of which is shown in phantom in FIG. 7) are received in the four separate stalls C, M, Y, B on the carriage  30  and have ink reception ports which respectively mate with ink delivery connectors  110 ,  112 ,  114 ,  116  on the printhead connector  100 . Each stall has a different printhead lockout configuration comprised of various vertically extending lockout posts  120 - 125  formed on the printhead connector  100  in different positions around the ink delivery connector ends  110 ,  112 ,  114 ,  116  so that each stall is different and can only be mated with a printhead  140  of complementary configuration. By way of illustration only, the left stall C is configured to receive a printhead containing cyan colored ink. The adjacent stall M is configured to receive magenta, the next stall Y to the right is configured to receive yellow ink and the stall B at the right side of the connector  100  is configured to receive a printhead containing black ink. 
     FIG. 8 shows a printhead  140  configured to be received in the cyan stall of the printhead connector  100 . The printhead  140  includes two rows downwardly directed inkjet nozzles  142  and a pivotally mounted handle  144  at the top for removing the printhead  104  from the carriage  30 . The cyan ink delivery connector  110  on the printhead connector is received in a generally vertically extending ink receiving tube  146  on the cyan printhead. Proximate the lower end of the ink receiving tube  146  is a lockout collar  148  integrally formed with the printhead  140  with a portion shown in phantom which has been broken off or otherwise removed at the factory so that the cyan configured printhead  140  can only be receivable in the cyan stall C of the printhead connector  100  to properly connect the ink delivery connector end  116  tube with the cyan printhead  140 . It will be appreciated that printheads may be mass produced with frangible collars  148  extending generally all the way around the ink receiving tube  146  and that selected portions of the collars  148  can be easily removed at the factory to thus create cyan, magenta, yellow and black printheads each having different configurations which are uniquely receivable only in the appropriate stalls of the printhead connector  100 . The partially removable or frangible collars  148  may be removed at selected locations whereby the remaining portions of the collars  148  are receivable only in the mating stalls on the printhead connector. Alternatively, it will be appreciated that the printhead connector lockout posts  120 ,  125  may be constructed so that they are easily broken off or otherwise removed in selected areas for mating with appropriately configured printheads. 
     The replaceable ink delivery tube system of the present invention comprised of the flexible ink delivery tubes  50 - 56  and printhead connector  100  is completed by the ink reservoir connector  70  (FIGS.  9  and  12 - 15 ) which is permanently affixed to an ink supply end of the ink delivery tubes. The reservoir connector comprises a plastic frame  72  having guide channels  73  which mate with guide rails on the printer frame and a vertically extending flange  74  to which a printed circuit board PCB, not part of the present invention, is rigidly attached. The frame  72  includes a pair of vertically extending sides  76 ,  78  and defines four parallel connector module stalls separated by vertically extending divider walls  80 ,  82 ,  84 . The frame is open at the front and rear sides so that the ink delivery ends of ink reservoirs  20 ,  22 ,  24 ,  26  may be received in the stalls from the front side of the printer. The front side of the reservoir connector  70  seen in FIG.  9  and shows modules, described below, having ink delivery inlets  50   i,    52   i,    54   i,    56   i,  air connections  90 ,  91 ,  92 ,  93  and electrical connectors  94 ,  95 ,  96 ,  97  which mate with like connections on the reservoirs, the modules being mounted in the module stalls and extending through the stalls in the frame  72  to the rear side of the printer. 
     Four reservoir connector modules  200 ,  202 ,  204 ,  206  are resiliently mounted in each of the four stalls of the frame  72  such that the four modules are forwardly and rearwardly moveable with respect to the frame and slightly laterally moveable with respect to the frame under the influence of a pair of compression springs  208 ,  210  extending between each module and spring seats on the frame  72  to permit the modules to readily connect to and disconnect from the ink reservoirs  20 ,  22 ,  24 ,  26  which are manually inserted from the front of the printer. Each module ink port  90 ,  91 ,  92 ,  93  receives ink from one ink reservoir  20 ,  22 ,  24 ,  26 , and the air connections  90 ,  91 ,  92 ,  93  deliver compressed air to the reservoirs. 
     The rear side of the reservoir connector  70  as seen in FIG. 12, includes a pair of quick release twist connectors  212 ,  214  which are easily gripped between the thumb and fore finger which can be rotated as desired to rotate locking shafts received in apertures in the printer frame to connect and disconnect the reservoir connector  70  from the printer frame. An air delivery manifold  216  is mounted on the rear of the upwardly extending flange  74  and includes a quick release connector for connecting and disconnecting the manifold  216  to a flexible air supply line which delivers air through four tubes  218 ,  220 ,  222 ,  224  to the modules  200 ,  202 ,  204 ,  206  to pressurize each of the four ink reservoirs when connected to the modules to cause the ink reservoirs to deliver ink under pressure through the ink delivery connections  50   i,    52   i,    54   i,    56   i  and the four ink supply tubes  50 ,  52 ,  54 ,  56  which are respectively connected to ink supply outlets  50   o,    52   o,    54   o,    56   o  on the rear side of the modules. Also shown is a a main electrical connector  230  extending through an aperture  232  in the flange  74  which connects to the circuit board and four electrical connections  234 ,  236 ,  238 ,  240  of conductors  248 ,  246 ,  244 ,  242  extending from the circuit board through the frame  72  to the connectors  94 - 97  on the front of the modules. Disconnection of the main air supply line from the manifold  216  and disconnection of an electrical conductor strip from the main electrical connector  230  is quickly made by from the rear side of the printer so that the entire reservoir connector including the permanently connected ink delivery tubes  50 ,  52 ,  54 ,  56  can be removed from the printer merely by rotating the quick release connectors  212 ,  214 . A rigid plastic tube clip  250  having a bayonet connector  252  which is readily slidably received in and removed from an aperture in the printer frame is also provided to hold the ink delivery tubes  50 ,  52 ,  54 ,  56  in the proper spaced relationship to each other proximate the reservoir connector  70 . 
     Ink reservoir lockouts  270  are provided to ensure that ink reservoirs are containing only one type of ink, for example pigment based ink, can be received in the reservoir connector. In the preferred embodiment, these lockouts take the form of four separate removable members  270  slideably received in slots  272  in the top portion of the frame  72  above the four modules. In the configuration shown, each lockout  270  has three horizontally spaced downwardly extending fins  274 ,  276 ,  278  which mate with ink reservoirs having four horizontally spaced upwardly extending fins  280 ,  282 ,  284 ,  286  (FIG. 11) to ensure that reservoirs containing one type (not color) of ink only, e.g. pigment based ink rather than dye based ink, can be received in the frame  72 . Separate lockouts (not part of this invention) are also provided near the front end of the reservoir stalls in the printer frame to ensure that reservoirs containing only the appropriate color of ink may be received in the four reservoir stalls. As seen in FIG. 9 one of the lockouts  270  has been removed to more clearly show the slots  272  in the frame in which the lockouts  270  are slideably received. Also note in FIG. 9 that the lockouts  270  each have vertically upstanding bosses  288  integrally formed thereon which, when the lockouts  270  are fully inserted into the slots  272  in the frame  72 , provide an additional means of affixing the printed circuit board to the front of the upstanding flange  74  at the top of the reservoir connector frame. 
     It is thus seen that an easily replaceable ink delivery tube system has been provided which is uniquely useable with ink of a selected type, e.g. pigment based ink or dye based ink but not both, due to the lockouts  270  provided at the ink reservoir connector  70  and which is uniquely connectable to printheads of a selected color due to the lockout collars  148  on the printheads and the lockout posts  120 - 125  provided on the printhead connector  100 . Removal of the entire system from the printer when it is desired to change from, e.g. pigment based ink to dye based ink, prevents fouling of the ink delivery system in a foolproof manner by inadvertent use of ink of the wrong type therein. The replacable delivery system is easily removed from the printer merely by disconnecting the air line and electrical connections at the reservoir connector  70  so that the reservoir connector can be removed from the printer, by removing the printheads from the carriage and then disconnecting the printhead connector  100  from the carriage  30  merely by squeezing the resilient finger tabs  102 ,  104  while pulling the printhead connector  100  from under the carriage  30  and by removing the ink delivery tube clip  130  from the rear tube guide  46  merely by sliding the bayonet connections to the proper direction for easy removal.