Abstract:
A solvent dispensing mechanism is fluidically coupled to create a substantially uniform wet region of a belt surface scrubber. Mechanisms for selectively engaging and disengaging the scrubber ensure free belt travel during flexible material transport and the cleaning of both surfaces during cleaning cycles. The system includes consumable piece-part elements for refurbishing and remanufacturing.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates generally to transport belts (sometimes referred to in the art as conveyor belts), particularly to a method and apparatus for cleaning a transport belt and, more specifically, to cleaning a print media transport belt in an ink-jet hard copy apparatus.  
           [0003]    2. Description of Related Art  
           [0004]    The art of ink-jet technology is relatively well developed. Commercial products such as computer printers, graphics plotters, copiers, and facsimile machines employ ink-jet technology for producing hard copy. The basics of this technology are disclosed, for example, in various articles in the  Hewlett-Packard Journal,  Vol. 36, No. 5 (May 1985), Vol. 39, No. 4 (August 1988), Vol. 39, No. 5 (October 1988), Vol. 43, No. 4 (August 1992), Vol. 43, No. 6 (December 1992) and Vol. 45, No. 1 (February 1994) editions. Ink-jet devices are also described by W. J. Lloyd and H. T. Taub in  Output Hardcopy [sic] Devices,  chapter 13 (Ed. R. C. Durbeck and S. Sherr, Academic Press, San Diego, 1988).  
           [0005]    [0005]FIG. 1 (PRIOR ART) depicts a hard copy apparatus, in this exemplary embodiment a computer peripheral, ink-jet printer,  101 . A housing  103  encloses the electrical and mechanical operating mechanisms of the printer  101 . Operation is administrated by an electronic controller  102  (usually a microprocessor or application specific integrated circuit (“ASIC”) controlled printed circuit board) connected by appropriate cabling to a computer (not shown). It is well known to program and execute imaging, printing, print media handling, control functions and logic with firmware or software instructions for conventional or general purpose microprocessors or with ASIC&#39;s. Cut-sheet print media  105 , loaded by the end-user onto an input tray  120 , is fed by a suitable paper-path transport mechanism (not shown) to an internal printing station where graphical images or alphanumeric text is created. A carriage  109 , mounted on a slider  111 , scans the print medium. An encoder subsystem  113  is provided for keeping track of the position of the carriage  109  at any given time. A set of individual ink-jet pens, or print cartridges,  115  “X” is mounted in the carriage  109  (generally, in a full color system, inks for the subtractive primary colors, cyan, yellow, magenta (X=C, Y, or M) and true black (X=K) are provided; in some implementations an ink-fixer chemical (X=F) is also used). An associated set of replaceable or refillable ink reservoirs  117  “XX” is coupled to the pen set by ink conduits  119 . Ink is deposited on the sheet of media  105  at a “print zone,” or “printing station,”  107 . Once a printed page is completed, the print medium is ejected onto an output tray  121 . The carriage scanning axis is conventionally designated the x-axis, the print media transit axis is designated the y-axis, and the printhead firing direction is designated the z-axis.  
           [0006]    For convenience of describing the ink-jet technology and the present invention, all types of print media are referred to simply as “paper,” all compositions of colorants are referred to simply as “ink,” and all types of hard copy apparatus are referred to simply as a “printer.” No limitation on the scope of invention is intended nor should any be implied.  
           [0007]    [0007]FIG. 2 is a schematic depiction of another ink-jet hard copy apparatus  210  as may be associated with the present invention. A writing instrument  115 X is provided with a printhead  214  having drop generators including nozzles for ejecting ink droplets onto an adjacently positioned print medium, e.g., a sheet of paper  105 , in the apparatus&#39; printing zone  107 . A perforated, endless-loop belt  232  is one type of known manner printing zone input-output paper transport. A motor  233  having a drive shaft  230  is used to drive a gear train  235  coupled to a belt pulley, or roller,  238  mounted on a fixed axle  239 . A biased idler wheel  240  provides appropriate tensioning of the belt  232 . The belt rides over a platen  236  (sometimes including heating devices) in the print zone  107  associated with a known manner vacuum induction system  237 . The paper sheet  105  is picked from an input supply (not shown) and its leading edge  254  is delivered to a guide  250 ,  252  where a pinch wheel  242  in contact with the belt  232  takes over and acts to transport the paper sheet  105  through the printing zone  107  (the paper path is represented by arrow  231 ). Downstream of the printing zone  107 , an output roller  244  in contact with the belt  232  receives the leading edge  254  of the sheet  105  and continues the paper transport until the trailing edge  255  of the now printed page is released.  
           [0008]    Ink-jet technology is used to describe the present invention even though it has wider applicability because the ink-jet environment typifies a transport belt use where the local environment may contain contaminants such as ink mist and paper dust which can soil a transport belt and clog perforations in a vacuum belt or even be sucked through the belt, contaminating the subjacent platen and other subsystems of the apparatus. Furthermore, the latest generation of ink-jet printers has found commercial success for economical color printing of high resolution graphics, including photographic reproductions, which require edge-to-edge paper printing (referred to as “full bleed”). Overspray and aerosol will build up on the belt over time. Not only does this affect performance of the belt itself, ink on the belt can be transferred undesirably to the back side of the print, particularly if the ink remains in a liquid or semi-fluidic state.  
           [0009]    It can also be recognized that this type of problem can occur in other vacuum transport systems such as for transporting thin sheets of metal where particulate flakes might be present or for coating processes where an aerosol spray is used on a passing receptor on the transport belt.  
           [0010]    Thus, there is a need for a method and apparatus for cleaning transport belts.  
         SUMMARY OF THE INVENTION  
         [0011]    A solvent dispensing mechanism is fluidically coupled to create a substantially uniform wet region of a belt surface scrubber. Mechanisms for selectively engaging and disengaging the scrubber ensure free belt travel during flexible material transport and the cleaning of both surfaces during cleaning cycles. The system includes consumable piece-part elements for refurbishing and remanufacturing.  
           [0012]    In a basic aspect, the present invention provides a method for cleaning a transport belt, comprising the steps of: positioning a cleaning member in non-contacting juxtaposition to a transport surface of the belt; and selectively repositioning the cleaning member into contact with the transport surface while distributing a cleaning solvent substantially uniformly across the cleaning member.  
           [0013]    In another basic aspect, the present invention provides a transport belt cleaning apparatus, said belt having a sheet material transporting surface, comprising: means for cleaning non-contactingly juxtaposed on each side of the belt; means for distributing a cleaning solvent substantially uniformly across cleaning members of the means for cleaning; and means for selectively engaging the cleaning means with the belt.  
           [0014]    In another basic aspect, the present invention provides an ink-jet hard copy apparatus comprising: a transport belt for media input-output; belt surface cleaners including a belt inner-surface cleaner and a belt outer-surface cleaner; a mechanism for releasably engagable the belt surface cleaners and with the belt surfaces respectively; and fluidically coupled to at least one of the belt surface cleaners, a belt cleaning solvent subsystem for dispensing solvent substantially uniformly onto the at least one belt surface cleaner prior to or during engagement of the at least one belt surface cleaner with the belt.  
           [0015]    In another basic aspect, the present invention provides a transport belt cleaning device for use with a supply of cleaning solvent, comprising: a wiper; a fluid manifold for evenly distributing a cleaning solvent across the wiper, including a fluidic coupling for connecting the fluid manifold to the supply of the cleaning solvent.  
           [0016]    In another basic aspect, the present invention provides an ink-jet hard copy apparatus endless-loop, vacuum-actuated, media transport belt cleaning system comprising: a supply of belt cleaning fluid; a fluid delivery subsystem coupled to the supply; a renewable first belt cleaning subsystem mounted adjacent an inner surface of the belt, including at least one belt wiper; a renewable second belt cleaning subsystem mounted adjacent an outer surface of the belt, wherein the first belt cleaning subsystem and second belt cleaning subsystem are contraposed with the belt therebetween and are selectively engagable and disengagable with the respective inner surface and outer surface, and wherein the second belt cleaning subsystem includes a cleaning fluid distribution subsystem for dispensing the fluid substantially uniformly across the second belt cleaning subsystem prior to and during engaging the second cleaning subsystem with the outer surface of the belt.  
           [0017]    Some advantages of the present invention are:  
           [0018]    it provides a self-contained subsystem which may be repaired, replenished, or replaced independently the transport belt subsystem;  
           [0019]    it provides commercial implementation using consumable parts which can be obtained and installed by the end user; and  
           [0020]    it provides a simple re-manufacture capability to the apparatus in which it is implemented.  
           [0021]    The foregoing summary and list of advantages is not intended by the inventors to be an inclusive list of all the aspects, objects, advantages and features of the present invention nor should any limitation on the scope of the invention be implied therefrom.  
           [0022]    This Summary is provided in accordance with the mandate of 37 C.F.R. 1.73 and M.P.E.P. 608.01(d) merely to apprise the public, and more especially those interested in the particular art to which the invention relates, of the nature of the invention in order to be of assistance in aiding ready understanding of the patent in future searches. Other objects, features and advantages of the present invention will become apparent upon consideration of the following explanation and the accompanying drawings, in which like reference designations represent like features throughout the drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0023]    [0023]FIG. 1 (PRIOR ART) is a perspective view drawing typifying an ink-jet hard copy apparatus.  
         [0024]    [0024]FIG. 2 (PRIOR ART) is a schematic elevation view illustration of a paper transport vacuum belt type ink-jet hard copy apparatus.  
         [0025]    [0025]FIG. 3 is a schematic elevation view illustration of a paper transport vacuum belt type ink-jet hard copy apparatus showing a first embodiment of belt cleaning devices in accordance with the present invention.  
         [0026]    [0026]FIG. 3A is a schematic elevation view illustration of a paper transport vacuum belt type ink-jet hard copy apparatus showing a second embodiment of belt cleaning devices in accordance with the present invention.  
         [0027]    [0027]FIG. 4 is a schematic elevation view illustration of a third embodiment of belt cleaning devices in accordance with the present invention.  
         [0028]    [0028]FIG. 4A is an overhead view illustration of details of the embodiment as shown in FIG. 4.  
         [0029]    [0029]FIG. 5 is a schematic diagram of a solvent dispensing subsystem in accordance with the present invention employable with the embodiment as shown in FIGS. 3A, 4 and  6 .  
         [0030]    [0030]FIG. 6 is a perspective view illustration of a solvent dispensing device in accordance with the present invention as shown in FIG. 5.  
         [0031]    [0031]FIG. 6A is a perspective view illustration of detail from FIG. 6.  
         [0032]    [0032]FIG. 7 is a perspective view illustration of an alternative embodiment of the present invention as shown in FIGS. 6 and 6A.  
         [0033]    [0033]FIG. 7A is a perspective view illustration of detail from FIG. 7. 
     
    
       [0034]    The drawings referred to in this specification should be understood as not being drawn to scale except if specifically noted.  
       DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0035]    Reference is made now in detail to a specific embodiment of the present invention, which illustrates the best mode presently contemplated by the inventors for practicing the invention. Alternative embodiments are also briefly described as applicable.  
         [0036]    Turning to FIG. 3, a belt cleaning subsystem  300  in accordance with the present invention is shown in an exemplary embodiment implementation as part of an ink-jet hard copy apparatus  210 ′ schematically represent by a framework  210 ″.  
         [0037]    The present invention comprises two subsystems: a belt  232  inner-surface cleaner  301  and a belt outer-surface cleaner  302 , wherein the “outer-surface” is a vacuum-holding transport surface of the belt. The cleaner  301 ,  302  subsystems are preferably independently serviceable. In the exemplary embodiment shown, the cleaner  301 ,  302  subsystems are subjacent a vacuum-box-platen  236 .  
         [0038]    The inner-surface cleaner  301  includes an inner-surface wiper mount  303 , such as a stiff, flat plate—e.g., a metal, sheet metal, or plastic plate—with a mounting flange  303 ′. The wiper mount  303  should be at least as wide as the belt  232  cross-sectional dimension and have a length to optimize wiping area and wiper absorbent capacity as the belt passes between the drive rollers  239 ,  240 . A belt inner-surface wiper  305  is affixed to the mount  303  such that a wiping surface is adjacent the inner-surface of the belt  232 . In order to prevent excessive wear it is preferable that the wiping surface to belt inner-surface have a clearance, e.g., approximately one millimeter (“mm”), when not being used to clean the inner-surface. It is preferred that this wiper  305  be fabricated of a dry, absorbent, lint-free material. For example, a three-to-five millimeter thick, felt pad, or a relatively high density, absorbent, sponge material may be employed. Launderable, reusable, pad materials can be employed. Disposable pad materials can be employed. In general, the contact surface of wiper, or pad,  305  material should be relatively smooth and somewhat compliant in order to clean the belt surface effectively. If made of a fiber-based material, the contact surface of the wiper  305  could be singed or otherwise treated as would be known in the art to prevent fibers from tracking onto the belt  232 . All wiper materials should be soft enough not to damage belt surfaces.  
         [0039]    The inner-surface wiper  305  can be glued to the mount  303  such that the entire subsystem is disposable and replaceable. Alternatively, the inner-surface wiper  305  can be releasably secured to the mount  303  in a known manner so that the belt inner-surface wiper  305  is removable and replaceable with a clean wiper replacement pad for a reusable mount  303 . The inner-surface wiper  305  should be equal to or slightly greater than the belt  232  width dimension.  
         [0040]    The outer-surface belt cleaner  302  subsystem could be a mirror embodiment of the inner-surface belt cleaner  301 , subjacent the belt  232  opposing the inner-surface belt cleaner  301  subsystem. Each subsystem  301 ,  302  can employ a known manner elevating subsystem to engage respective wipers with the belt  232  inner and outer surfaces. However, as the outer surface of the belt  232  will have a far greater degree of deposits, it has been found to be preferable to use both wet and dry wiping of at least the outer surface.  
         [0041]    As shown in the embodiment of FIG. 3 therefore, a wet pressure pad  307  and a dry pressure pad  309  are provided in series for sequentially wiping the belt  232  outer surface. In the belt travel direction, arrow  231 , the wet pressure pad  307  is upstream and the dry pressure pad  309  downstream. A pad holder  311  is mounted in the apparatus  210 ′ subjacent the belt  232  and opposing at least some part of the inner-surface belt cleaner  301  subsystem. The pad holder  311  is provided with positive pressure biasing members  313 ,  315  for each pad  307 ,  309 . The pad holder  311  is mounted on at least one return biasing member  317 . In the shown embodiment, a clearance, for example in the range of approximately one to three millimeters, is provided between the reach of each pads&#39;  307 ,  309  cleaning surface and the outer surface of the belt  232  when the subsystem  302  is disengaged. The belt  232  during a paper transport and printing operational cycle through the print zone  107  is thus free to travel between the inner-surface cleaner  301  and the outer-surface cleaner  302 . To clean the belt  232 , the elevating subsystem  319  (in this embodiment a cam having a mechanical linkage (not shown) for end-user manipulation) lifts the holder  311  until the gap between the wet pressure pad  307  and dry pressure pad  309  in the holder  311  and the belt surface is closed. Then, the holder  311  elevating subsystem  319  continues upward until the gap between the inner-surface belt cleaner  301  is also closed. Thus, both surfaces of the belt  232  are being wiped by the belt wiping pads  305 ,  307 ,  309  when the elevating subsystem  319  is engaged. It should be recognized that separate elevating subsystems can be provided for each cleaner subsystem  301 ,  302 . The wet pressure pad  307  is pre-soaked with a solvent appropriate to the type of ink employed (or other aerosol chemical being used in a non-ink-jet environment). The dry pressure pad  317  should be absorbent of the solvent and ink residue and solvent mixtures.  
         [0042]    Either the entire belt outer-surface cleaner  302  subsystem can be replaceable as a unit or each pad can be separately replaceable in the same manner as with the inner-surface wiper  305 . The wet and dry cleaning pads may be replaceable at every cleaning cycle or be designed to be more durable as needed.  
         [0043]    In operation, such when ink smearing is noticed on the back side of a finished print or during routine maintenance by the end-user, fresh wipers are installed if needed, and the cam  319  is turned (counter-clockwise in this illustration) to raise the holder  311  and contained pressure pads  307 ,  309  up against the outer surface of the belt  232  (direction indicated by arrows on the belt drive rollers  239 ,  240 ) until the biasing members  313 ,  315  exert enough force to push the belt  232  upward until its inner surface is pressed against the inner surface wiper  305 . The pressure will squeeze some solvent out of the wet pad  307 . Note that since the belt  232  is perforated for transmission of a vacuum in this embodiment, some solvent will be passed through the perforations to the inner surface of the belt and, consequently, onto the inner surface wiper  305 . The inner wiper  305  can be of a material having a higher surface energy than that of the transport surface wipers  307 ,  309  in order to help solvent to be drawn through the belt perforations. Thus, both sides of the belt  232  are “washed.” Downstream, the inner surface wiper  305  and the dry pressure pad  309  will absorb the mixture of solvent and particulate residue washed from the belt  232 .  
         [0044]    After a predetermined, recommended time of contact, the cam  319  is reversed and the belt  232  released from the cleaner  301 ,  302  subsystems. While a predetermined pressure of the wipers against the belt surfaces can be tailored, it should also be recognized that solvent can be transferred to the belt via capillary forces created by the interface between the belt and wipers when the belt is moving.  
         [0045]    In order to eliminate reverse bending of the belt and reduce belt fatigue, the inner surface cleaning subsystem can also be movable into engagement with the belt only during a cleaning operation.  
         [0046]    Turning now to FIG. 3A, an alternative embodiment is depicted in which the outer-surface cleaner  302  includes a rolled web  321  mounted on a rotating shaft  322 . The web  321  is a rolled supply of belt wiping material, preferably an absorbent fabric such as a fiber-based polyester, rayon, absorbent cotton cloth, or the like textile. A web material having a thickness in the range of approximately 45 um to 140 um has been employed. The web  321  is mounted on the shaft  322  for free rotation with the shaft. A known manner tensioner  323  and out-of-web sensor  325  are associated with the web  321 . The web  321  material is stretched from the roll across two support shafts, or adjunct rollers,  327 ,  328  to span the pressure pads  307 ,  309  subjacent the belt  232  outer surface. The web  321  is then captured by a driven, web take-up spool  329 . The direction of rotation of the take-up spool, and thus the web material, is indicated by arrow  331 . The spool  329  can be driven by a stepper motor to advance the web  321  in predetermined increments so that a fresh segment of web material is properly positioned subjacent the belt  232  for each cleaning cycle. A clearance of approximately 1 mm to 3 mm between the cleaner web  321  and belt  232  transport surface is provided when the web is disengaged from the belt transport surface.  
         [0047]    A solvent suitably selected as appropriate for a particular ink formulation (or other particulate matter sought to be “washed” from the belt) is provided in a solvent dispensing subsystem  333  (schematically represented for any known manner local or remote, replaceable, refillable or otherwise serviceable solvent dispensing subsystem) with fittings  335  for fluidically coupling solvent to the wet pressure pad  307 . Known manner techniques for dispensing and monitoring of solvent to the wet pressure pad  307 —such as with appropriate valves and pumps—can be employed.  
         [0048]    In operation during a belt cleaning cycle, the cam  319  is used to lift the holder  311  until the web material is in contact with the belt  232  outer surface and the inner-surface wiper  305  is in contact with the belt inner surface. Solvent is pumped into the wet pressure pad  307 , generally at a fixed delivery rate or to a predetermined appropriate volume. The solvent will be transferred to the web  321  material superjacent the wet pressure pad  307  and thus to the belt  232  outer surface.  
         [0049]    During a cleaning cycle, the web  321  can be wound onto the spool  329  in a direction  331  opposite of the belt  232  motion  231  to cause a stronger scrubbing force against the belt outer surface. As wound onto the spool  329  during a cleaning cycle, the web  321  will carry away dissolved ink on the belt  232  outer surface from the contact-cleaning zone. Some solvent will go through the belt perforations and onto the inner surface thereof, cleaning some ink from the perforations in addition to the inner surface itself. Any solvent solution left on the belt  232  downstream of the wet pressure pad  307  will be wiped off, absorbed by the web being pressed against the belt outer surface by the dry pressure pad  309 . Alternatively, the web  321  can be stationary during the cleaning cycle for winding onto the spool  329  after the holder  311  is lowered to disengage the inner-surface wiper  305  and web  321  from respective belt  232  surfaces. This has been found to increase the useful effective life of the web  321  material; however it should be noted that during the cleaning cycle itself the web material then does not carry dissolved ink away from the cleaning zone.  
         [0050]    The outer-surface cleaner  302  can be a completely replaceable, unitary, module or an in situ refurbishable subsystem wherein components such as the web  321 , wipers  307 ,  309 , and solvent dispensing subsystem  333  are individually replaceable or otherwise serviceable. Used pads  305 ,  307 ,  309  and web material can be manufactured to be disposable, end-user replaceable, or remanufacture-type consumables.  
         [0051]    In operation during an paper transport cycle through the print zone  107 , the belt  232  is preferably free to travel between the belt lower span&#39;s superjacent inner-surface cleaner  301  and a subjacent web  321  span region. To clean the belt  232 , the elevating subsystem  319  lifts the holder  311  until the gap between the web  321  region spanning the wet pressure pad  307  and dry pressure pad  309  and the belt  232  transport surface is closed. Then, the holder  311  elevating subsystem  319  continues upward until the gap between the inner-surface belt cleaner  301  and belt inner surface is also closed. Thus, both surfaces of the belt  232  are being wiped when the elevating subsystem  319  is engaged. Alternatively, the inner-surface belt cleaner  301  can also be separately selectively positionable such that reverse bending of the belt  232  and belt fatigue can be avoided. Note also that the wet and dry pads  307 ,  309  and therefore separate regions of the web  231  can be made selectively engagable with the belt transport surface separately.  
         [0052]    As noted, either the entire belt outer-surface cleaner  302  subsystem can be replaceable as a unit or each pad and the web can be separately replaceable in the same manner as with the inner-surface wiper  305 . It is also contemplated that depending upon the frequency of cleaning, the web  321  may be removed from the take-up spool  329  and re-loaded onto the shaft  322  and reused until such time as it is no longer effective in cleaning the belt  232  outer surface. In a more costly system, an automated rewind mechanism can be provided. The wet and dry cleaning pads  305 ,  307 ,  309  may be replaceable at the same time as the web  321  or be designed to be more durable as needed.  
         [0053]    To summarize the end-user operation, when ink smearing is noticed on the back side of a finished print, or at the time of standard printer maintenance, predetermined throughput intervals, or even continuously for heavy duty printing such as full-bleed type printing cycles, the cam  319  is turned (counter-clockwise in this illustration) to raise the holder  311  and contained pressure pads  307 ,  309  up against the web  321  spanning the pads which then is pushed into contact with the moving belt  232  (see direction arrow  231 ) until the biasing members  313 ,  315  exert enough force to push the belt  232  upward until its inner surface is against the inner-surface wiper  305 . Generally, solvent will transfer from the pad to the web by contact. A predetermined pressure between the two can be provided to cause some solvent to be squeezed out of the wet pad  307  and through the web  321  material. Since the belt  232  is perforated, some solvent will be passed through the perforations to the inner surface of the belt and, consequently, the inner-surface wiper  305 . Thus, both sides of the belt  232  are “washed.” Downstream, the inner-surface wiper  305  and the web  321  which are in contact with the dry pressure pad  309  will absorb the mixture of solvent and particulate residue washed from the belt  232 . After a predetermined or recommended time of contact, the cam  319  is reversed and the belt  232  released from the cleaner  301 ,  302  subsystems.  
         [0054]    [0054]FIG. 4 shows an alternative embodiment of the belt outer-surface cleaner  302  subsystem. The solvent, represented by the arrow labeled “SOLVENT IN,” is in a containment and delivery subsystem (not shown) located remotely from the outer-surface cleaner  302  subsystem, coupled to the wet pressure pad  307  by a fitting  400 . The solvent containment can be refillable or replaceable or otherwise serviceable. To improve the “washing” and “drying” action of the outer-surface cleaner  302  subsystem, the dry pressure pad  309  and wet pressure pad  307  are spaced further apart. A pair of additional web support shafts, or rollers,  401 ,  402  are mounted in-board of each pad  307 ,  309  to create separate span regions  403 ,  404  of the web superjacent to each pad individually. A biased, central web roller  405  can be mounted in the holder  311  between the pads  307 ,  309  and lower than the pads, forming therebetween an inter-pad loop region of web  321  to move the dry pressure pad  309  a greater effective distance away from the wet pressure pad  307  and preventing cross-contamination. Generally, depending on the solvent solution and the physical properties of the absorbent web material, solvent solution may wick and spread on the web in different areal dimensions. Therefore, any specific implementation should be tailored to prevent cross-contamination between wet and dry regions. The distance between a dry and wet pad may be varied. With careful design, the roller  405  might be eliminated, reducing manufacturing complexity and cost.  
         [0055]    It should also be recognized that in the embodiments depicted, the dry pad  309  is used to increase the cleaning effectiveness, but when the solvent solution is benign (such as just or mostly water) or highly evaporative such that no residue is left on the belt when the next media sheet is obtained at the input, the dry pad subsystem also can be eliminated.  
         [0056]    Note also that the solvent fitting  400  might instead be coupled to the central web roller  405  in a manner to dispense the solvent directly onto the web  321  itself rather than via wet pressure pad  307 , creating a larger effective wet area of web material as illustrated schematically by orthogonal projection FIG. 4A.  
         [0057]    [0057]FIG. 5 is a schematic, symbolic diagram of a belt cleaning system  500  where the solvent solution  501  is provided from a replaceable or refillable container  503 . A fluid coupling, such as flexible tubing,  504  is connected between the container  503  and a dispensing manifold  505  via a pump  502 , such as a metering, precision pump as would be known in the art. Appropriate check valves and flow control as would be known in the art can be added if necessary. In order to prevent overflow, solvent  501  is pumped to the manifold  505  in a predetermined volume or for a predetermined time, depending on the programmed cleaning cycle parameters or until the end-user retracts the belt cleaning subsystem  300  using the cam  319  lift mechanism associated with the holder  311 .  
         [0058]    [0058]FIGS. 6 and 6A show a first embodiment of a dispensing manifold  505  with the wet pressure pad  307  removed (FIG. 6 is an exploded view) to expose the working features of the manifold. The manifold  505  has a body member  601  with a pad mating surface  603  having a solvent distribution channel  605 . The body member  601  is appropriately mounted to the holder  311  (FIGS. 3 and 4). The pressure pad  307  can be secured to the mating surface  603  in any known manner. The fluid coupling tubing  504  (FIG. 5) is connected to each of a plurality of solvent input ports  607 . Each input port  607  leads to a riser section  607 ′ for delivering pumped solvent  501  (represented by numbered arrows in FIG. 6A) into the distribution channel  605 . Riser sections  607 ′ may have different sizes depending on the dispensing volume desired, using the web material properties to provide control for a substantially uniform spreading of the solvent. Solvent  501  pumped into the distribution channel  605  will spread along the channel floor and will be wicked into the pad substantially uniformly. A distribution channel  605  of about one millimeter depth has been employed, allowing rapid distribution of the solvent  501  to the underside of the pad  307 . Having a riser section  607  also allows excess solvent not absorbed by the pad  307  (and by the superjacent web  321  material in the embodiment of FIG. 4) and used during the cleaning cycle to drain away. As the solvent  501  will evaporate from the pressure pad  307  when not in use, it acts as a cap, reducing or substantially eliminating solvent evaporation.  
         [0059]    Either the pressure pad  307  or the entire dispensing manifold assembly  505  can be disposable or refurbishable. A replaceable pad  307  can include a stiffening mounting shim (not shown) having a complementary central channel matching the distribution channel of the manifold body  601 . Such a shim could include pad side walls for preventing solvent from wicking horizontally out of the pad.  
         [0060]    [0060]FIGS. 7 and 7A show an alternative embodiment for a solvent dispensing manifold  5051 . The manifold  505 ′ has an upper body  700  member and a lower body  702  member. The body members can be mounted to each other in a known manner. A single solvent solution input port  701  is provided at one end  700 ′ of the upper body  700 . The input port  701  leads to a horizontal solvent accumulation chamber  705  formed by providing grooves in the members  700 ,  702  for mating between the upper body  700  and lower body  702 . A single input port  701  provides the advantage of reducing the number of input tubes  504  coupled to the manifold  505  to a single input tube and thereby easing solvent flow and volume control requirements. This embodiment may be beneficial where a peristaltic pump, having a relatively slow pumping rate, is used. The travel distance for the solvent  501  from the chamber  705  through the risers  607 ′ will be maintained by this configuration such that delivery to each riser  607 ′ is substantially equal.  
         [0061]    The pad  307  may get fouled with ink which is transferred from the web material in the embodiment of FIG. 3A or FIG. 4 after some cleaning operations depending on the amount of ink cleaned, how often the web is advanced, and how much solvent is used. Operations can be tailored for each specific implementation to obtain an optimal service life for replaceable pads  307 .  
         [0062]    The foregoing description of the preferred embodiment of the present invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form or to exemplary embodiments disclosed. Obviously, many modifications and variations will be apparent to practitioners skilled in this art.  
         [0063]    The present invention has been described in an implementation for an ink-jet hard copy apparatus, but this is not intended as a limitation (nor should any be implied) as it is known to use vacuum belts in many conveyor systems for flexible materials. While the outer-surface cleaner  302  is shown as two replaceable pads, one wet and one dry, a single pad having a solvent wet region upstream and separated by gap from a dry, solvent-absorbing region may also be employed to reduce manufacturing costs and to simplify pad replacement. Moreover, it should be recognized that automated, electromechanical devices can be employed for activating the cleaner mechanisms to wipe the belt.  
         [0064]    Similarly, any process steps described might be interchangeable with other steps in order to achieve the same result. The embodiment was chosen and described in order to best explain the principles of the invention and its best mode practical application, thereby to enable others skilled in the art to understand the invention for various embodiments and with various modifications as are suited to the particular use or implementation contemplated. It is intended that the scope of the invention be defined by the claims appended hereto and their equivalents. Reference to an element in the singular is not intended to mean “one and only one” unless explicitly so stated, but rather means “one or more.” Moreover, no element, component, nor method step in the present disclosure is intended to be dedicated to the public regardless of whether the element, component, or method step is explicitly recited in the following claims. No claim element herein is to be construed under the provisions of 35 U.S.C. Sec. 112, sixth paragraph, unless the element is expressly recited using the phrase “means for . . .”