Abstract:
An ink jet aerosol control includes a carrier frame, a carrier, at least one airflow channel and a filter. The carrier is disposed and moveable within the frame and selectively creates a high-pressure zone and a low-pressure zone. The airflow channel joins the high-pressure zone to the low-pressure zone. The filter is disposed in association with the airflow channel.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to ink jet printers, and, more particularly, to removing excess aerosol in ink jet printers.  
           [0003]    2. Description of the Related Art  
           [0004]    An ink jet printer typically includes an ink jet cartridge assembly with a printhead mounted under a body. The body includes one or more ink reservoirs which are in fluid communication with the printhead. The printhead includes a plurality of heaters, which are respectively positioned in association with nozzles in a nozzle plate. The heaters are selectively actuated during printing to jet ink droplets from the corresponding nozzles in the nozzle plate.  
           [0005]    Expelling ink through the printhead, during maintenance and printing, releases aerosol. Movement of the printhead causes uncaptured aerosol to swirl within the printer and external to the printer, allowing the aerosol to reach and ultimately rest upon numerous internal and external component parts of the printer and the work area. This contamination is undesirable as it can lead to failure of certain mechanical and electrical components. Uncontrolled release of aerosol is an increasing concern, due in large part to the current trend of decreasing droplet size, since smaller droplets have a greater tendency to stay airborne.  
           [0006]    Capture of aerosol is not a new concept in itself. One ink jet printing apparatus includes a carriage moveable within a printer section. Exhaust pipes are positioned on opposite sides of the carriage, relative to the scan directions. A fan draws aerosol droplets from each of the exhaust pipes and through a filter.  
           [0007]    Another ink jet printing system includes an ink jet nozzle plate, which jets ink droplets through an elongated slot onto a print medium carried by a drum. A vacuum is applied to a transverse opening positioned above the ink-jetting zone for removing aerosol ink droplets.  
           [0008]    A mist reduction system for ink jet printers has a nozzle unit jetting an ink stream at selected ink dot placement locations onto the print medium, which is carried by a drum. A suction pump removes ink mist condensing on a deflection electrode and control electrode and also removes deflected ink from a gutter.  
           [0009]    An ink jet recorder includes a recording head, which is moveable in transverse directions relative to a print medium. The recording head includes a pair of air stream ducts positioned on either side of an orifice plate defining a side shooter design with respect to a print medium. A dual fan assembly includes fan blades, which are respectively positioned within the corresponding air ducts. The fan blades are driven, using a rack and pinion arrangement, as the recording head is moved in scan directions relative to the stationary rack. Air is drawn in through air inlet openings and is discharged through air outlet openings associated with each respective fan blade.  
           [0010]    Common to each of these systems is the use of active fans or suction pumps with a filter to remove the aerosol. Additional components are generally undesirable, adding to the cost, potential for breakdown, and increased effort in installing and maintaining the system.  
           [0011]    What is needed in the art is a manner for controlling ink jet aerosol during maintenance and printing, without the use of an additional fan, to displace harmful aerosols to a filter.  
         SUMMARY OF THE INVENTION  
         [0012]    The present invention relates to an ink jet aerosol control assembly and method using carrier movement as a piston pump for removing aerosols within a printer.  
           [0013]    Carrier motion produces airflow required to sweep away the aerosols when the carrier moves from a spitting to a printing position. As the carrier moves from a spit position towards the page, and while the aerosols are still suspended, a high-pressure zone is created in front of the carrier and a low-pressure zone is created behind the carrier. This pressure difference creates airflow from the high-pressure zone to the low-pressure zone. A preferred airflow path, as well as leak paths surrounding the carrier, provides a conduit for airflow to occur. The carrier and geometry surrounding the carrier act as a piston and cylinder to create the pressure difference. The preferred airflow path is most effective while the carrier is over the spit zone. Once exposed, the preferred airflow path is no longer in the flow path between the high-pressure zone and the low-pressure zone. Airflow of sufficient velocity should therefore be provided to collect the aerosols on the filter prior to breaking flow. The manifold area may be created as large as possible to increase the pressure difference between the air inlet (spit zone) and air outlet (manifold).  
           [0014]    In another embodiment the carrier is a piston to pump aerosols through a filter associated with an airflow path created at least in part by openings in a printer frame adjacent the carrier. As the carrier moves through the frame, during the printing process, a high-pressure zone is created in front of the carrier, according to its direction of movement and a low-pressure zone is created behind the carrier. Apertures defined in the frame allow air to pass from the high-pressure zone to the low-pressure zone. The air may be filtered in or adjacent the frame to remove airborne aerosol.  
           [0015]    An advantage of the present invention is that it is more efficient, channeling airflows that before now had not been used within printing systems and had even been considered detrimental thereto.  
           [0016]    Another advantage of the present invention is that the design is simple, replacing expensive components with existing components and wall structures.  
           [0017]    A further advantage is that such system eliminates the need for certain components that are subject to wear and breakdown without inducing additional wear on the remaining components.  
           [0018]    Yet another advantage is that airflow may be effected without the use of a fan to filter aerosols within the printer. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0019]    The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention will be better understood by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying drawings, wherein:  
         [0020]    [0020]FIG. 1 is a schematic view of a first embodiment of the present invention;  
         [0021]    [0021]FIG. 2 is a schematic view of the first embodiment, showing the carriage in the maintenance area;  
         [0022]    [0022]FIG. 3 is a schematic view of the first embodiment, showing the carriage moving from the maintenance area to the printing area;  
         [0023]    [0023]FIG. 4 is a schematic view of the first embodiment, showing the carriage leaving the maintenance area and entering the printing area;  
         [0024]    [0024]FIG. 5 is a graph showing the rate of airflow versus the position of the carriage for the first embodiment; and  
         [0025]    [0025]FIG. 6 is a schematic view of a second embodiment of the present invention.  
         [0026]    Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate one preferred embodiment of the invention, in one form, and such exemplifications are not to be construed as limiting the scope of the invention in any manner. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0027]    Referring now to the drawings, and particularly to FIGS. 1-4, there is shown an embodiment of a printer  8  including an ink jet aerosol control  10  for collecting airborne aerosol during printing on a print medium (not shown) such as paper, transparency, etc. Ink jet aerosol control  10  generally includes a carrier  12  having an ink jet cartridge assembly, a carrier frame  14 , at least one airflow channel  16  and a filter  18 .  
         [0028]    Carrier  12  periodically releases ink in predetermined locations. Ink jet aerosol is released as part of the expulsion of the ink at such locations. Carrier  12  is generally supported and maintained in carrier frame  14 . Carrier  12  generally traverses back and forth along a linear path inside carrier frame  14 , creating a high-pressure area  20  in the direction of the movement of carrier  12  and a low-pressure area  22  behind carrier  12 . Air tends to move from a high-pressure area  20  to a low-pressure area  22  and accordingly, seeks to move along leak paths  23  defined between outer edges  24  thereof and frame  14 . Carrier  12  generally discharges ink in a maintenance area  26  and in a printing area  28 .  
         [0029]    Frame  14  and channel wall  32  define an airflow channel  16  which may be of any size, shape or configuration suitable for transferring the air from high-pressure zone  20  to low-pressure zone  22 , but generally should be constructed based upon available space considerations and aerodynamic considerations, understanding that greater airflow rates provide improved cleaning abilities. An inlet or spit zone  34  provides an entrance to airflow channel  16  and outlet or manifold  36  provides an exit. A well  38  may be defined along a portion of airflow channel  16 , sized and positioned to capture the non-airborne particles, i.e. drops of ink condensed from ink jet aerosol  30 . Anywhere along airflow path  16  may be a filter  18 , from spit zone  34  through manifold  36 , although it is generally preferred to position filter  18  between well  38  and manifold  36 .  
         [0030]    Air is cleaned when carrier  12  moves through maintenance area  26 . As carrier  12  initiates movement from maintenance area  26  toward printing area  28 , as shown in FIG. 2, airflow through airflow channel  16  is generally at its height.  
         [0031]    The airflow rate decreases as such motion continues as shown in FIGS. 3 and 4. FIG. 5 is a graph of the change in flow rate versus position of carrier  12  where FIG. 2 corresponds to point X 0 , FIG. 3 to X 1  and FIG. 4 to X 2 . The graph shows the decrease in airflow is related to the effort needed to move air from high-pressure area  20  through airflow channel  16  to low-pressure area  22  as compared to the effort needed to circumvent airflow channel  16  via leak path  23  extending all the way from high-pressure area  20  to low-pressure area  22 . Since improved flow rate is desired for increasing cleaning ability, manifold  36  and airflow channel  16  may be made as large as possible, and the proximity of carrier  12  and frame  14  between spit zone  34  and manifold  36  may be made as closed to airflow as possible.  
         [0032]    Referring to FIG. 6, a second embodiment, includes a printer  50  with an ink jet aerosol control  52 . Ink jet aerosol control  52  collects airborne aerosol during printing on a print medium such as paper, transparency, etc. Ink jet aerosol control  52  generally includes a carrier  54  having an ink jet cartridge assembly, a carrier frame  56 , at least one airflow channel  58  and a filter  60 .  
         [0033]    Carrier  54  periodically releases ink in predetermined locations together with ink jet aerosol. Carrier  54  is generally supported and maintained in carrier frame  56 .  
         [0034]    Carrier  54  generally traverses back and forth along a linear path inside frame  56 , creating a high-pressure area  62  in the direction of the movement of carrier  54  and a  25  low-pressure area  64  behind carrier  54 . Air tends to move from high-pressure area  62  to low-pressure area  64  and accordingly, seeks to move along leak paths  66  defined between outer edges  68  of carrier  54  and frame  56 . Carrier  54  generally discharges ink in a maintenance area  70  and in a printing area  72 .  
         [0035]    Frame  56  defines an airflow channel  58  which may be of any size, shape or  30  configuration suitable for transferring the air from high-pressure zone  62  to low-pressure zone  64 , but generally should be constructed based upon available space considerations and aerodynamic considerations, understanding that greater airflow rates provide improved cleaning abilities.  
         [0036]    In operation, carrier  54  moves in carrier frame  56 , creating high-pressure area  62  and low pressure area  64 . High-pressure area  62  is positioned adjacent a leading edge of moving carrier  54  and low-pressure area  64  is positioned adjacent a trailing edge of carrier  54 . High-pressure area  62  and low-pressure area  64  may switch sides relative to carrier  54 , since carrier  54  traverses back and forth in frame  56 . Airflows from high-pressure area  62  to low-pressure area  64  through leak paths  66  and at least one airflow channel  58  defined in frame  56 . Air is filtered while moving from high-pressure area  62  to low-pressure area  64  through at least one airflow channel  58 .  
         [0037]    While this invention has been described as having a preferred design, the present invention can be further modified within the spirit and scope of this disclosure. For instance, one may understand that both embodiments may be employed in a single printer. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.