Abstract:
A completely self-contained replaceable cartridge for micro jet dispensing assemblies is thinner than the spacing between a standard “DIP” socket. Each cartridge body contains a preferably embedded digitally operated micro jet piezoelectric ejector, a tubular capillary reservoir and fixed connecting pins spaced to removably plug into a standard dual in line packaging (DIP) socket strip or board to receive digital ejection signals. A plurality of the individual replaceable cartridges can be closely positioned together in “banks” which plug into standard DIP sockets. One or more “banks” can be plugged into sockets on a housing containing a chamber into which the micro-droplets are deposited. An air movement device may be included with the housing to disperse volatile material that has been ejected into the chamber. The chamber preferably contains a heatable surface onto which the volatile fluids are ejected from the orifices and whereby instantaneous volatilization of the fluid will take place. In an alternate embodiment, each self-contained replaceable cartridge has its own individual heatable surface in the form of a heater mounted adjacent the ejection orifice and one or more additional connecting pins to provide power to operate the heater. A multiplicity of different volatile fluids may be dispensed from a compact assembly in response to command signals from a controller connected to the dispensing assembly.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention lies in the field of self-contained micro jet fluid droplet dispensers. 
     2. Background of the Prior Art 
     Ink jet printing devices are well known in the art. Some U.S. patents which have discussed various ink jet printing devices are U.S. Pat. Nos. 5,299,016, 5,681,757, 6,029,896, 5,658,802 and 5,444,467 which are incorporated herein by reference. Such devices are preferably digitally operated. Ink jet printing devices function by transforming electrical inputs to mechanical outputs, which in a proper device produces fluid micro-droplets from tiny orifices. 
     Specialized devices primarily utilizing the properties of piezoelectric materials include applying micro-droplets of liquid dye for improved laser surgery (U.S. Pat. No. 5,092,864); producing micro-optical components from polymeric materials (U.S. Pat. No. 5,498,444); distributing epoxy die-bond adhesive using a printhead and a micro jet array of printheads (U.S. Pat. No. 5,681,757); applying various reagents in miniaturized diagnostic arrays (U.S. Pat. No. 5,658,802); producing microlenses (U.S. Pat. No. 5,707,684); and with the aid of a specialized printhead, depositing liquid solder onto a substrate (U.S. Pat. No. 5,772,106). 
     High density ink jet printheads are shown in U.S. Pat. Nos. 5,365,645, 5,227,813 and 5,235,352. Most people are familiar with the self-contained ink jet cartridges used in their ink-jet printers. Though small, these cartridges are still somewhat bulky. They contain contacts, a digitally driven generally piezoelectric ejection device or a plurality of ejection devices and individual reservoirs connected to the ejection devices, all contained in a housing. 
     SUMMARY OF THE INVENTION 
     A self-contained replaceable cartridge for micro jet dispensing assemblies has a cartridge body comprising a thin panel having opposed side surfaces substantially larger than the thickness of the cartridge body and an outwardly facing peripheral edge. A digitally operated micro-droplet ejection device having an outwardly facing ejection orifice is carried by the cartridge body and preferably embedded therein. In fluid communication with the ejection device is an elongated tubular fluid reservoir also carried by the cartridge body and preferably embedded in a channel formed in the side surface of the cartridge body. The elongated tubular fluid reservoir is preferably in the form of an elongated capillary tube disposed in a channel which has a serpentine form. 
     Digital operating signals for the micro-droplet ejection device are provided by a pair fixed connecting pins mounted in the body. Each connecting pin extends from the body and is configured for engagement and disengagement with one of the pair of dual in line sockets in a conventional connector strip having a plurality of closely spaced dual in line sockets. The connecting pins of the cartridge can be quickly plugged into and unplugged from any one of the pair of closely spaced dual in line sockets which receive the connecting pins and support the cartridge to make a closely packed assembly of individually replaceable dispensers. 
     In an alternate embodiment, each self-contained replaceable cartridge has a heater supported by the cartridge body in front of and spaced from the ejection orifice. The heater is mounted to the cartridge body by means of a stand-off strip adjacent to the ejection orifice and is preferably narrower than the thickness of the panel comprising the cartridge body. A connecting pin mounted in the cartridge body and fixed thereto is connected to the heater by means of a depressed wiring channel in the side surface of the panel. The additional fixed connecting pin embedded in the body provides electrical power for operation of the heater. All of the digitally operated ejection device, the tubular reservoir, the connecting pins and the wiring are preferably depressed in openings or channels below the level of the side surface of the body. This prevents parts of the replaceable cartridges from interfering with each other when they are placed in closely packed assemblies in the form of “banks” of self-contained replaceable cartridges which may be installed and replaced simply by plugging them into the connecting sockets or unplugging them from the sockets. 
     One or more banks having a plurality of the self-contained replaceable cartridges can be removably mounted onto connecting strips on a housing containing a chamber which forms a multi-fluid dispensing device. The chamber preferably includes a heatable surface with the ejection orifices positioned to deposit ejected micro-droplets onto the heated surface for rapid volatilization of any one or more of a plurality of fluids contained in the replaceable cartridges. A preferred embodiment has two banks of the self-contained replaceable cartridges having ejection orifices arranged to eject micro-droplets into the chamber and/or onto the heatable surface. Each of the banks of replaceable cartridges are separated and positioned in a radial orientation with respect to the chamber. The housing preferably has an air movement device and a passageway which allows air to traverse the chamber and exit the dispensing assembly device through an outlet where the volatilized fluid can be sensed by a user. 
     The self-contained replaceable cartridges of the invention are uniquely suitable for dispensing fluid materials or combinations of materials which generate odors, fragrances or aromas for sensing. Each cartridge element has a simple integrated construction for one fluid dispensing. Virtually an unlimited number of the cartridge elements may be assembled to make a complex dispensing cartridge assembly with multi-fluid capabilities. Maintenance of such an assembly is easy because individual cartridges are easily replaced or changed and may be refilled. The fluid in each replaceable cartridge is independent of the fluid in any other cartridge and there is little or no contamination between fluids. The design is sturdy and highly reliable and may be operated in any orientation. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a schematic representation of a digitally operated transducer operating to produce micro-droplets in drop-in-demand mode; 
     FIG. 2 is a perspective view of a cartridge body used to make the replaceable cartridge for micro jet dispensing assemblies of the present invention; 
     FIG. 2 a  is a cross section of the cartridge body of FIG. 2 on the lines  2   a — 2   a  of FIG. 2; 
     FIG. 3 is a perspective view of the cartridge body of FIG. 2 further containing an elongated tubular fluid reservoir, a micro-droplet ejection device and a pair of fixed connecting pins in electrical contact with the ejection device; 
     FIG. 4 is a cross section of a digitally operated micro-droplet ejection device carried by the cartridge body in FIGS. 3 and 5; 
     FIG. 5 is a perspective view of a modification of the replaceable cartridge of FIG. 3 further including a heating device spaced apart from and in line with the ejection orifice of the ejection device with an additional fixed connecting pin for the heater; 
     FIG. 6 is a perspective view of a self-contained assembly illustrating how the replaceable cartridges are employed to create a compact fluid dispensing device; 
     FIG. 7 is an exploded and perspective view of the compact multi-fluid dispensing device of FIG. 6 illustrating how a plurality of replaceable cartridges can be arranged in banks to make the compact multi-fluid dispenser; 
     FIG. 8 illustrates one version of a connecting strip having paired sockets in the form of closely spaced dual in line sockets into which the individual replaceable cartridge bodies are plugged for easy installation, removal and replacement. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The present invention discloses a specialized, replaceable, “plug-and-play” cartridge or assembly of cartridges which preferably utilize drop-on-demand ink-jet technology. In piezoelectric-based, drop-on-demand ink-jet printing systems, illustrated schematically in FIG. 1, a volumetric change in the fluid within a printing device is induced by the application of a voltage pulse to a piezoelectric transducer which is mechanically coupled to the fluid. The volumetric change in the transducer causes pressure/velocity transients to occur in the fluid which are directed in a way which produces a drop of fluid from the orifice of the device. Here a voltage pulse is applied only when a drop is desired, as opposed to continuous ink-jet printers where droplets are continuously produced, but directed to the target substrate only when needed by a charge and deflect method. Further details about ink-jet printing systems and control apparatus is found in U.S. Pat. Nos. 5,498,444 and 5,707,684 which are incorporated herein by reference. In the Figures that follow, a preferred replaceable cartridge of the invention will be generally designated by the reference numeral  10  as shown in FIG.  3 . 
     FIG. 2 shows the cartridge body  12  for the replaceable cartridge  10  of FIG.  3 . Cartridge body  12  comprises a thin panel  14  having opposed side surfaces  16  and  18  substantially larger than the thickness of the panel  14 . Side surface  16  is the top or upper surface and side surface  18  is the bottom surface more clearly seen in FIG. 2 a . Side surfaces  16 ,  18  together define an outwardly facing peripheral edge  20  extending around the body panel  14 . Body panel  14  is preferably provided with a handle  22  which is thinner than the thin panel  14  to make it more accessible for grasping and handling. Various operating parts are preferably embedded in the side surface of the cartridge body. Embedded in this context connotes a channel or depressed opening which provides an interference fit between the part and the channel or opening that tends to hold the part in place. The term is broad enough to include an adhesive or substance which fills part or all of the space around the part and may be used in place of or in addition to frictional holding forces. 
     Cartridge body  12  is preferably molded with certain depressions in one or both of the side surfaces which makes possible a self-contained replaceable cartridge  10 . Body  12  has an ejection device opening  24  formed in side surface  16  and an opening  26  in outwardly facing peripheral edge  20  for the tip portion of the ejection device. Leading into the back end  28  of opening  24  is a tubular and serpentine channel  30  depressed below surface  16  and occupying a considerable portion of the area of side surface  16 . Channel  30  will be used to embed a tubular reservoir in cartridge body  12  below surface  16 . Channel  30  is seen in cross section in FIG. 2 a.  Finally, surface  16  of body  12  has a depressed opening  34  and a depressed opening  36  which are configured to receive connecting pins to make electrical connections with pairs of dual in line sockets in a connector strip. Behind openings  34 ,  36  runs a wiring channel  38  which extends to ejection device opening  24  and has branches  40 ,  41  for purposes which will be seen later. Body  12  may have a truncated corner portion  42  for handling. 
     The replaceable cartridge  10  for micro jet dispensing assemblies is shown in FIG. 3. A digitally operated micro-droplet ejection device  44  is embedded in opening  24  of cartridge body  12  below surface  16 . Ejection device  44  has a connection end  46  and an ejection end  48  ahead of connection end  46 . A tip portion  50  of ejection end  48  is positioned in opening  26  extending from outwardly facing peripheral edge portion  20 . The outer end of tip portion  50  of ejection end  48  terminates in ejection orifice  52 . An elongated tubular reservoir  54  is embedded in channel  30  below surface  16 . Tubular reservoir  54  has an open fill opening  56 . The other end of reservoir  54  enters opening  24  through its back end  28  where it is coupled in fluid communication with the connection end  46  of ejection device  44 . A pair of fixed connecting pins  58  and  60  are embedded respectively in depressed openings  34  and  36  in body  12 . Connecting pin  58  has a pin connector  62  and connecting pin  60  has a pin connector  64 . The pin connectors  62 ,  64  are in electrical contact with ejection device  44  through suitable wires  66  running in channel  38  below surface  16 . All of the operating parts are carried by the body  12  and preferably embedded below the surface  16  to make the thin compact self-contained replaceable cartridge  10 . The openings in side  16  may be filled with a suitable material, such as epoxy or covered with a thin cover to contain them. 
     FIG. 4 is an enlarged view in cross section of micro jet droplet ejection device  44 . Ejection device  44  has its connection end  46  connected to elongated tubular reservoir  54  by means of a rubber plug  68  or other suitable means. The open end  70  of reservoir  54  leads into a fluid chamber  72  in fluid communication with the interior of ejection end  48 . Ejection end  48  is preferably piezoelectric material having is back end adhesively connected with connection end  46  by suitable means such as adhesive  74 . End  48  is provided with suitable electrical connections through thin film metallic layers connected to contacts  76  and wires  66  to connecting pins  58 ,  60 . The thin film metallic layers cannot be seen. Ejection orifice  52  in the projecting end portion  50  cannot be seen because this view is a cross section. 
     A modified replaceable cartridge  78  having all of the features of replaceable cartridge  10  is shown in FIG.  5 . Cartridge body  80 , like cartridge body  12 , comprises a thin panel  82  like panel  14  having opposed side surfaces  84 ,  86  substantially larger than the thickness of panel  82 . Side surface  84  is the top or upper surface and side surface  86  is the bottom surface of thin panel  82 . Side surfaces  84 ,  86  together define an outwardly facing peripheral edge  20  extending around body panel  82 . Body panel  82  is provided with a handle  22  which is thinner than panel  82  to make it more accessible for grasping and handling. Cartridge body  80  is molded with depressions in one or both side surfaces in the same way as cartridge body  12 . Cartridge body  80  has the same ejection device opening  24  having the same ejection device  44  embedded therein below surface  84 . 
     A tip portion  50  of ejection end  48  is positioned in the opening  26  extending from peripheral edge portion  20  and terminating in the ejection orifice  52  which is hidden in FIG.  5 . Leading into back end  28  of opening  24  is a tubular serpentine channel  30  depressed below surface  84  and occupying a considerable portion of area of side surface  84 . Elongated tubular reservoir  54  is embedded in channel  30  below surface  84 . Fill opening  56  is seen extending from peripheral edge portion  20  of panel  82 . The other end of reservoir  54  enters opening  24  through back end  28  where it is coupled in fluid communication with the connection end  46  of ejection device  44 . Cartridge  80  has the same pair of fixed connecting pins  58  and  60  embedded respectively in openings  34  and  36 . The pin connectors  62  and  64  are in electrical contact with ejection device  44  through suitable wires  66  running in channel  38  below surface  84 . 
     What is different about cartridge body  80  of replaceable cartridge  78  is the presence of a built in heater  88  supported by cartridge body  80  in front of and spaced from ejection orifice  52  by means of a stand off strip or strips  90 . A third fixed connecting pin  92  is embedded in depressed opening  94  in side surface  84 . Fixed connecting pin  92  has a pin connector  96  connected via wires  66 , channel  38  and branches  40 ,  41  in electrical connection with heater  88  spaced in front of the ejection orifice. The fixed connecting pins are fixed to the cartridge body with the spacing preferably configured to fit into a pair of closely spaced dual in line sockets which receive the connecting pins and support the cartridge to make a close packed replaceable dispenser. The third connecting pin  92  can be spaced to fit a connecting strip having three in line closely spaced sockets or a separate connecting strip or some other connector means. Since one of the connecting pins  58 ,  60 ,  92  can effectively act as the ground for heater  88  and ejection device  44 , it is only necessary to have three connecting pins to power up both electrical elements. If connecting pin  58  acts as the ground, its wire or wires  66  will connect to both ejection device  44  and heating element  88 . 
     The modification of replaceable cartridge  78  makes it possible to provide banks of stand alone assemblies which have built in heaters to quickly vaporize micro-droplets which are ejected onto the surface of heater  88  when heater  88  is operated at an elevated temperature. A useful fluid for use in replaceable cartridges  10 ,  78  is a fluid which produces a fragrance or aroma for the user to experience when the fluid is volatilized. 
     FIGS. 6 and 7 disclose an assembly  100  of replaceable cartridges for micro jet dispensing of multiple fluids in a compact assembly made possible by the unique replaceable cartridges  10  or  78 . The assembly of FIGS. 6 and 7 rely upon the particular configuration of replaceable cartridge  10  of FIG. 3, however with suitable modification of the connections, the modified embodiment of FIG. 5 could be employed in a compact assembly of FIGS. 6 and 7 also. FIG. 8 shows one version of a connector strip having dual in line connecting sockets of a convention dual-in-line packaging device which is preferred for use with the replaceable cartridge  10  of FIG.  3 . 
     FIGS. 6 and 7 show a pair of separate banks  102  comprising eight aligned replaceable cartridges  10  in close side by side arrangement. Each replaceable cartridge  10  has the embedded ejection device  44  and an extending tip portion  50  of device  44  together with the connecting pins  58  and  60 . Connecting pins  58  and  60  are configured to plug into dual in line sockets which are arranged in rows  104  and  106  of connector strip  108 . The fixed connecting pins  58 ,  60  preferably provide mechanical support for each of the individual replaceable cartridges  10  in the banks  102 . 
     FIG. 7 is a partially exploded view of the compact assembly  100 . A connecting strip  108  for each of the banks  102  of replaceable cartridges  10  are mounted onto a housing  110 . Connecting wires  112  run from each of the individual sockets  109  in the rows of sockets  104 ,  106  in connector strip  108  which are connected to individual pins in an input socket  113 . Referring now to FIG. 6, socket  113  is removably engageable with a companion socket  114 . When companion socket  114  is plugged into input socket  113 , a ribbon connector  116  is in electrical contact with a pulse generator/relay bank combination  118  which in turn is connected to a programmed computer  120  having a digital output card along with appropriate power supplies as is conventional for controlling and driving ink jet printing devices. 
     The pair of connecting pins  58 ,  60  of each of the eight replaceable cartridges  10  in each bank of replaceable cartridges  102  are removably connected in electrical contact with one of the sockets  104 ,  106  in connector strip  108 . Each individual cartridge  10  is removably replaceable simply by pulling it out to disconnect it and pushing another cartridge into its place. 
     Returning now to FIGS. 7 and 8, it can be seen that housing  110  contains a chamber  122  and the ejection orifices  52  of tip portions  50  are positioned to eject droplets of fluid into chamber  122 . A blower or fan  124  connected to housing  110  comprises a means for moving air through a passageway  126  through chamber  122  where it exits through an outlet  130  in a cone shaped extension  132  in housing  110 . It can be seen that two banks of cartridges  102  are separated from each other and disposed in radial orientation with respect to the chamber  122  so that all of the orifices are able to eject micro-droplets of fluid into chamber  122 . This is somewhat like the arrangement of cylinders in a “V8” automobile engine or a radial airplane engine. It can be seen that this structure could be altered so that one or more additional banks  102  of replaceable cartridges could be arranged in radial orientation to deposit micro-droplets into the chamber  122 . 
     Referring now to FIG. 7, a heater  134  having a heatable surface is preferably mounted in chamber  122  and provided with electrical connections through the connector  113 . Heater  134  is mounted such that each of the ejection orifices  52  of the digitally operated ejection devices  44  of replaceable cartridges  10  are positioned to deposit micro-droplets onto the heatable surface of heater  134 . Heater  134  can be left on to keep the heatable surface at an elevated temperature for instant vaporization of droplets deposited thereon or it can be switched on when a dispensing cycle is about to be initiated. These devices are very small and the heatable surface is preferably a very rapidly heatable surface because the compact assembly  100  and the replaceable cartridges are very small and do not have much mass. The heatable surface of heater  134  should be wettable with the fluids deposited thereon. Both the heatable surface of heater  134  and the heater  88  can be provided by what is known as a surface mount resistor or platinum RTD. Surface mount resistors are thin film resistors available commercially which have low mass and low power requirements and are inexpensive. Surface mount resistors are available from Newark Electronics, East Brunswick, N.J. or Dallas, Tex. and the RTD&#39;s from Omega Engineering, Stamford, Conn. 
     In the best mode, the micro jet dispensing device is a piezoelectric device and the reservoir  54  is capillary tubing. The use of capillary tubing eliminates the necessity of static head pressure control at the orifice of the piezoelectric device, greatly simplifying the general construction of the device and improving its reliability. Thus, the device can be operated in any orientation without concern about loss of “head”. Alternately, the reservoir can be shaped in any way, as long as it is kept close to the micro-droplet ejection device so that pressure at the orifice is close to that at the end of the tubing. The reservoir  54  may be filled by means of a fine needled syringe through the opening  56 . The tubular reservoir is first evacuated with a syringe. The cartridge body is preferably made from plastic material and contains all parts of the replaceable cartridge. 
     The rubber plug  68  in the ejection device is preferably silicon rubber. The capillary tubing in a prototype is identified as PTFE 30 TW tubing from Cole Parmer Instrument Co., Vernon Hills, Ill., having an outer diameter of 0.031 inches and an inner diameter of 0.012 inches. The polycarbonate material Lexan works well for the cartridge body. 
     The orifice of the ejection device would typically be in the range of about 30 to 70 microns in diameter in a nickel orifice tube plate. In an exemplary embodiment, the capillary tubing mentioned above has a length of 600 millimeters, producing a reservoir volume of about 45 microliters. The micro-droplets have a volume of about 50 to 100 picoliters. If one “shot” requires 50 of those droplets, one could expect the total number of “shots” before the reservoir was depleted would be in the range of about 17,000 to about 8500. 
     Of particular importance is the ability to use conventional dual in line packaging or “DIP” sockets which are standardized for use in computer assembly. They have a 0.3 inch spacing between rows with a 0.1 inch spacing within rows from socket to socket. The thickness of the thin panel in a prototype was made to be not more than about 0.095 inches thick which permits side by side installation of the replaceable cartridges in standard “DIP” sockets. 
     Although the preferred embodiment is illustrated with depressions for the tubular fluid reservoir, ejection device, connecting pins and wiring channels in only one side surface of the cartridge body, it is evident that some of the depressed areas could be in one side of the body while others were in the other side surface of the body. 
     Although the invention has been disclosed above with regard to a particular and preferred embodiment, it is not intended to limit the scope of the invention. For instance, although the inventive method has been set forth in a prescribed sequence of steps, it is understood that the disclosed sequence of steps may be varied. It will be appreciated that various modifications, alternatives, variations, etc. may be made without departing from the spirit and scope of the invention as defined in the appended claims.