Abstract:
According to aspects of the embodiments there is provided a cassette cleaning web having an agent metering tube that can apply oil via a drip pipe to a web as it enters a nip within the fusing surface. Dispensing the oil as it enters the nip increases the transportation and the holding capacity of the web. The cassette cleaning web can reduce the oil-on-copy to less than 3 mg/copy and more specifically to less than 1 mg/copy which would allow for adequate post finishing applications while still using amino functionalized fuser oil in the fuser subsystem. The cassette cleaning web reduces the contamination of the oil-sump because used web materials are wound up and oil or contaminate materials like wax, toner are retained in the spent web cartridge. This invention enables reduced oil-on-copy, eliminates the bulky and expensive release agent management system, and also provides a direct cleaning to the surface of the fuser roll.

Description:
BACKGROUND 
     This disclosure relates in general to an image forming apparatus comprising a fuser cleaner web for cleaning a surface like a fuser roll, and more particularly, to the application of a cleaning agent to the surface using the fuser cleaner web and a metering channel with apertures. 
     Electrophotographic image-forming machines are used to transfer images onto paper or other medium in both printing and copier systems. Generally, a photoconductor is selectively charged and optically exposed to form an electrostatic latent image on the photoconductor surface. Toner is deposited onto the charged photoconductor surface. The toner has a charge; thus, it will adhere to the photoconductor surface in areas corresponding to the electrostatic latent image. The toner image is transferred to the paper or other medium. The toned paper is heated by any of several methods including a fuser roller system and the toner in image-wise configuration is fused to the paper. 
     The fuser roll used in the fuser roller system eventually becomes contaminated with debris containing toner or by-products of toner and paper. This contamination usually takes the form of a film which eventually builds up and adversely affects the release properties and overall print life of the fuser roll. 
     Various systems have been used to deliver release agent fluid to the fuser roll including ones that use oil soaked rolls and wicks with and without supply sumps as well as oil impregnated webs. The oil soaked rolls and wicks generally suffer from the difficulty in that they require a sump of oil to replenish the roll and the wick as its supply of release agent is depleted by transfer to the fuser roll. Furthermore, a wick suffers from the difficulty of a relatively short life due to accumulation and chemical interaction. The web systems, on the other hand are limited in the quantity of oil they can deliver since the web materials leak oil when saturated to high levels. The oil leaks are very undesirable and can decrease print quality because they can form oil blotches. Furthermore, excess oil which ends up on fused substrate (in the release agent film-splitting event in the fuser nip) can interfere with post finishing applications such as book-binding, Magnetic Ink Character Recognition (MICR) encoding, lamination, and the like. In the past, various treatments to the print as well as the utilization of different fuser oils minimized the issue. 
     For the reasons stated above, and for other reasons stated below which will become apparent to those skilled in the art upon reading and understanding the present specification, there is a need in the art for a fuser oil applicator and cleaner in a single web cartridge system. Furthermore, there is a need for an improved cleaning agent dispenser in a single web cartridge system. 
     SUMMARY 
     According to aspects of the embodiments, there is provided a cassette cleaning web having an agent metering tube that can apply oil via a drip pipe to a web as it enters a nip within the fusing surface. Dispensing the oil as it enters the nip increases the transportation and the holding capacity of the web. The cassette cleaning web can reduce the oil-on-copy to less than 3 mg/copy and more specifically to less than 1 mg/copy which would allow for adequate post finishing applications while still using amino functionalized fuser oil in the fuser subsystem. The cassette cleaning web reduces the contamination of the oil-sump because used web materials are wound up and oil or contaminate materials like wax, toner are retained in the spent web cartridge. This invention enables reduced oil-on-copy, eliminates the bulky and expensive release agent management system, and also provides a direct cleaning to the surface of the fuser roll. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates a schematic view of an imaging apparatus in accordance to an embodiment; 
         FIG. 2  is a schematic perspective view of a cleaning web with a metering channel including a plurality of apparatus for dispensing a cleaning agent on the cleaning web in accordance to an embodiment; 
         FIG. 3  is an illustration of the web cartridge and drip dispenser in accordance to an embodiment; 
         FIG. 4  is a side view of the web cartridge employing a one event oil exposure strategy in accordance to an embodiment; 
         FIG. 5  is a side view of the web cartridge employing a two event oil exposure strategy in accordance to an embodiment; and 
         FIG. 6  illustrates oil-on-copy as a function of oil-drip speeds in accordance to an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     While the present invention will be described in connection with preferred embodiments thereof, it will be understood that it is not intended to limit the invention to that embodiment. On the contrary, it is intended to cover all alternatives, modifications and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims. 
     Aspects of the disclosed embodiments relate to a fuser apparatus comprising a fuser roll; at least one web nip roll; a metering channel including a plurality of apertures, wherein each aperture is adapted to dispense by dripping a cleaning agent to a fuser cleaner web; and a fuser cleaner web disposed between the fuser roll and the web nip roll, wherein the fuser cleaner web cleans the fuser roll while supplying the cleaning agent to the fuser roll. 
     The disclosed embodiments further include a fuser apparatus wherein the plurality of apertures are aligned in a plane on the metering channel that faces away from the fuser cleaner web. 
     Still further, the disclosed embodiments may further include the fuser apparatus wherein the plurality of apertures are evenly spaced on the metering channel. 
     The disclosed embodiments further include a fuser apparatus wherein the cleaning agent flows around the outside of the metering channel and drops from the bottom of the metering channel onto the fuser cleaner web. 
     The disclosed embodiments further include a fuser apparatus wherein the cleaning agent is chosen from silicon oils and functionalized silicone oils. 
     The disclosed embodiments further include a fuser apparatus wherein the silicon oil is a polydimethylsiloxane (PDMS). 
     The disclosed embodiments further include a fuser apparatus wherein the functionalized silicon oils are chosen from amino-functionalized PDMS oils and mercapto-functionalized PDMS oils. 
     In another embodiment, a printing machine in which a print medium receives an electrostatic image comprising an electrostatic applicator for applying an image to a print medium; a fuser roll mounted for rotation in the printing machine for applying heat to the print medium to bond said electrostatic image to the print medium; and apparatus to apply a cleaning agent to the fuser roll further comprising: a drive mechanism for rotating a supply reel with web material towards the fuser roll; a metering channel including a plurality of apertures, wherein each aperture is adapted to dispense by dripping a cleaning agent on the web material before it is extended across the fuser roll; a take-up reel positioned to receive the web material after it is extended across the fuser roll for engagement therewith; at least one application roller mounted for rotation between the supply reel and the take-up reel adjacent to the fuser roll, the application roller forming a nip with the fuser roll through which the web material extends, the nip applying the dispensed cleaning agent during engagement of the web material with the fuser roll. 
     Another embodiment may include a cleaning cartridge removably mountable to supply a cleaning agent to a surface of a fuser roller of a printing apparatus, the cleaning cartridge comprising: a cleaning agent metering tube with an inlet port and a plurality of outlet apertures arranged along its longitudinal extent, wherein each outlet aperture is adapted to dispense by dripping a cleaning agent to a web material; a drive mechanism for rotating a supply reel with web material towards the fuser roller; a take-up reel positioned to receive the web material after it is extended across the fuser roller for engagement therewith; at least one application roller mounted for rotation between the supply reel and the take-up reel adjacent to the fuser roller, the application roller forming a nip with the fuser roller through which the web material extends, the nip applying the dispensed cleaning agent during engagement of the web material with the fuser roll. 
     Still further, the disclosed embodiments may include the cleaning cartridge wherein the cleaning agent flows around the outside of the cleaning agent metering tube and drops from the bottom of the cleaning agent metering tube onto the web material. 
     The term “print media” or sheet generally refers to a usually flexible, sometimes curled, physical sheet of paper, plastic, or other suitable physical print media substrate for images, whether precut or web fed. 
     The term “printing system” as used herein refers to a digital copier or printer, xerographic printing machine, printing apparatus, bookmaking machine, facsimile machine, multi-function machine, or the like and can include several marking engines, as well as other print media processing units, such as paper feeders, finishers, and the like. The term “Print job” or “document” can include a plurality of digital pages or electronic pages to be rendered as one or more copies on a set of associated sheets of print media, each page, when rendered constituting the front or backside of a sheet. The pages of a print job may arrive from a common source and, when rendered, be assembled at a common output destination. 
     In as much as the art of electrophotographic printing is well known, the various processing stations employed in the  FIG. 1  printing machine will be shown schematically and their operation described briefly with reference thereto. Various other printing machines could also be used, and this is only an example of a particular printing machine that may be used with the invention. 
       FIG. 1  is a partial schematic view of a digital imaging system, such as the digital imaging system of U.S. Pat. No. 6,505,832, which is hereby incorporated by reference. The imaging system is used to produce an image such as a color image output in a single pass of a photoreceptor belt. It will be understood, however, that it is not intended to limit the invention to the embodiment disclosed. On the contrary, it is intended to cover all alternatives, modifications and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims, including a multiple pass color process system, a single or multiple pass highlight color system, and a black and white printing system. 
     Referring to  FIG. 1 , an Output Management System  660  may supply printing jobs to the Print Controller  630 . Printing jobs may be submitted from the Output Management System Client  650  to the Output Management System  660 . A pixel counter  670  is incorporated into the Output Management System  660  to count the number of pixels to be imaged with toner on each sheet or page of the job, for each color. The pixel count information is stored in the Output Management System memory. The Output Management System  660  submits job control information, including the pixel count data, and the printing job to the Print Controller  630 . Job control information, including the pixel count data, and digital image data are communicated from the Print Controller  630  to the Controller  490 . 
     The printing system preferably uses a charge retentive surface in the form of an Active Matrix (AMAT) photoreceptor belt  410  supported for movement in the direction indicated by arrow  412 , for advancing sequentially through the various xerographic process stations. The belt is entrained about a drive roller  414 , tension roller  416  and fixed roller  418  and the drive roller  414  is operatively connected to a drive motor  420  for effecting movement of the belt through the xerographic stations. A portion of photoreceptor belt  410  passes through charging station A where a corona generating device, indicated generally by the reference numeral  422 , charges the photoconductive surface of photoreceptor belt  410  to a relatively high, substantially uniform, preferably negative potential. 
     Next, the charged portion of photoconductive surface is advanced through an imaging/exposure station B. At imaging/exposure station B, a controller, indicated generally by reference numeral  490 , receives the image signals from Print Controller  630  representing the desired output image and processes these signals to convert them to signals transmitted to a laser based output scanning device, which causes the charge retentive surface to be discharged in accordance with the output from the scanning device. Preferably the scanning device is a laser Raster Output Scanner (ROS)  424 . Alternatively, the ROS  424  could be replaced by other xerographic exposure devices such as LED arrays. 
     The photoreceptor belt  410 , which is initially charged to a voltage V 0 , undergoes dark decay to a level equal to about −500 volts. When exposed at the exposure station B, it is discharged to a level equal to about −50 volts. Thus after exposure, the photoreceptor belt  410  contains a monopolar voltage profile of high and low voltages, the former corresponding to charged areas and the latter corresponding to discharged or developed areas. 
     At a first development station C, developer structure, indicated generally by the reference numeral  432  utilizing a hybrid development system, the developer roller, better known as the donor roller, is powered by two developer fields (potentials across an air gap). The first field is the AC field which is used for toner cloud generation. The second field is the DC developer field which is used to control the amount of developed toner mass on the photoreceptor belt  410 . The toner cloud causes charged toner particles to be attracted to the electrostatic latent image. Appropriate developer biasing is accomplished via a power supply. This type of system is a noncontact type in which only toner particles (black, for example) are attracted to the latent image and there is no mechanical contact between the photoreceptor belt  410  and a toner delivery device to disturb a previously developed, but unfixed, image. A toner concentration sensor  200  senses the toner concentration in the developer structure  432 . 
     The developed but unfixed image is then transported past a second charging device  436  where the photoreceptor belt  410  and previously developed toner image areas are recharged to a predetermined level. 
     A second exposure/imaging is performed by device  438  which comprises a laser based output structure which is utilized for selectively discharging the photoreceptor belt  410  on toned areas and/or bare areas, pursuant to the image to be developed with the second color toner. At this point, the photoreceptor belt  410  contains toned and untoned areas at relatively high voltage levels, and toned and untoned areas at relatively low voltage levels. These low voltage areas represent image areas which are developed using discharged area development (DAD). To this end, a negatively charged, developer material  440  comprising color toner is employed. The toner, which by way of example may be yellow, is contained in a developer housing structure  442  disposed at a second developer station D and is presented to the latent images on the photoreceptor belt  410  by way of a second developer system. A power supply (not shown) serves to electrically bias the developer structure to a level effective to develop the discharged image areas with negatively charged yellow toner particles. Further, a toner concentration sensor  200  senses the toner concentration in the developer housing structure  442 . 
     The above procedure is repeated for a third image for a third suitable color toner such as magenta (station E) and for a fourth image and suitable color toner such as cyan (station F). The exposure control scheme described below may be utilized for these subsequent imaging steps. In this manner a full color composite toner image is developed on the photoreceptor belt  410 . In addition, a mass sensor  110  measures developed mass per unit area. Although only one mass sensor  110  is shown in  FIG. 1 , there may be more than one mass sensor  110 . 
     To the extent to which some toner charge is totally neutralized, or the polarity reversed, thereby causing the composite image developed on the photoreceptor belt  410  to consist of both positive and negative toner, a negative pre-transfer dicorotron member  450  is provided to condition the toner for effective transfer to a substrate using positive corona discharge. 
     Subsequent to image development a sheet of support material  452  is moved into contact with the toner images at transfer station G. The sheet of support material  452  is advanced to transfer station G by a sheet feeding apparatus  500 , described in detail below. The sheet of support material  452  is then brought into contact with photoconductive surface of photoreceptor belt  410  in a timed sequence so that the toner powder image developed thereon contacts the advancing sheet of support material  452  at transfer station G. 
     Transfer station G includes a transfer dicorotron  454  which sprays positive ions onto the backside of sheet  452 . This attracts the negatively charged toner powder images from the photoreceptor belt  410  to sheet  452 . A detach dicorotron  456  is provided for facilitating stripping of the sheets from the photoreceptor belt  410 . 
     After transfer, the sheet of support material  452  continues to move, in the direction of arrow  458 , onto a conveyor  600  which advances the sheet to fusing station H. Fusing station H includes a fuser assembly, indicated generally by the reference numeral  460 , which permanently affixes the transferred powder image to sheet  452 . Preferably, fuser assembly  460  comprises a heated fuser roller  462  and a backup or pressure roller  464 . Sheet  452  passes between fuser roller  462  and pressure roller  464  with the toner powder image contacting fuser roller  462 . In this manner, the toner powder images are permanently affixed to sheet  452 . After fusing, a chute, not shown, guides the advancing sheet  452  to a catch tray, stacker, finisher or other output device (not shown), for subsequent removal from the printing machine by the operator. The fuser assembly  460  may be contained within a cassette, and may include additional elements not shown in this figure, such as an endless fuser belt or endless fuser web (not the fuser cleaner web) around the fuser roller  462 . In typical printing machines, this belt or web has been kept relatively short to minimize the size of the fuser assembly or cassette. 
     Controller  490  regulates the various printer functions. The controller  490  is preferably a programmable controller, which controls printer functions hereinbefore described. The controller  490  may provide a comparison count of the copy sheets, the number of documents being recirculated, the number of copy sheets selected by the operator, time delays, jam corrections, and the like. The control of all of the exemplary systems heretofore described may be accomplished by conventional control switch inputs from the printing machine consoles selected by an operator. Conventional sheet path sensors or switches may be utilized to keep track of the position of the document and the copy sheets. 
     The foregoing description illustrates the general operation of an electrophotographic printing machine incorporating the fuser apparatus of the present disclosure therein. Not all of the elements discussed in conjunction with  FIG. 1  are necessarily needed for effective use of the invention. Instead, these elements are described as a machine within which embodiments of the invention could operate. 
       FIG. 2  illustrates the fuser assembly  460  in greater detail. The fuser roll  462  coming into contact with the toner image bearing surface of the copy sheet is internally provided with a heater (H) for supplying the thermal energy required for fusing the toner powder and fixing the same to the copy sheet. A pressure roller  225  rendered movable between a fixing position in which it is in pressure contact with the fuser roll  462  and a non-fixing position in which it is separated from the fuser roll  462 . The fuser roll  462  driven in the direction of arrow  207  and the take-up roll  215  through shaft  220  are moved by a motor (not shown) under the control of controller  490 . A web material  210  composed of a heat-resistant sheet material such as non-woven cloth is wound as a roll on a supply reel and is maintained in contact with the fuser roll  462  by a pressure roller  225  in the course of transport to the take-up roll  215 . The web material absorbs any gelled oil, wax, toner, paper fiber and any other debris on the fuser roll  462 . The contaminants are collected on the web material and will be moved out of the system when the take-up roll  215  is replaced. The idea of adding oil to a web as it is entering the nip with the fusing surface decreases waste and increases effective oil application. Thus more oil can be transported by the web than a typical pre-saturated web can support. The web configuration can be single or double nip and several locations of oil addition are possible in double nip set-ups like shown in  FIG. 4  and  FIG. 5 . The benefits are that the web self-cleans as gelled oil, wax, toner, paper fiber and any other stuff will collect on the web and will be moved out of the system with the used web. 
     A metering channel, cleaning agent metering tube  230  adds a cleaning agent such as an oil to the web material  210  as it is entering or immediately prior to contact with the nip formed with the fusing surface. The metering channel  230  has an entering port for receiving a cleaning agent  240  from a pump  235  under the supervision of controller  490 . The metering channel has a plurality of apertures  245 ,  247  that are aligned in a plane on the metering channel that faces away from the web material  210 . The dripping rate is a function of the rate of cleaning agent that flow into the entering port and the dimensions and numbers of apertures at the metering channel.  FIG. 6  shows the relationship of oil-on-copy for different drip rates. The cleaning agent  240  flows around the outside of the metering channel  230  and drops from the bottom of the metering channel  230  onto the web material  210 . 
     The cleaning agent  240  is chosen from silicon oils such polydimethylsiloxane (PDMS) and functionalized silicone oils such as amino-functionalized PDMS oils and mercapto-functionalized PDMS oils. However, the cleaning agent  240  can comprise alcohol, butoxyethanol, 1-tert-butoxypropanol, propylene glycol ethers, propylene glycol co-polymers, ethylene oxide condensates (Merpol® kerosene, hexanes, heptanes, isobutylmethyl ketone, methylethyl ketone, and/or hydrogen peroxide, citric acid, acetic acid, linear siloxanes (hexamethyldisiloxane, octamethyltrisiloxane, or the like) and cyclic siloxanes (octamethyltetracyclosiloxane, decamethylpentacyclosiloxane, or the like), aminofucntional oligosiloxanes, poly(oxy-1,2-ethaediyl), alpha-(undecyl)-omega-hydroxy, to the region of the document along with water, a surfactant such sodium dodecylsulfate, dioctylsulfosuccinate, benzensulfonic acid, a polydimethylsiloxane (PDMS) based surfactant or fluorosurfactant. The amino-functional group release agents comprise at least one of: polydimethylsiloxane (PDMS), .alpha.-APS functional PDMS, and other functional fusing agents, as described, for example, in U.S. Pat. No. 6,743,561, the complete disclosure of which is incorporated herein by reference. 
     Web parameters  265  such as oil drop speed, and web material  210  speed, and other parameters such as attributes of the print media and the web material can be inputted into the controller  490  for optimal control of the dispensing/cleaning process. 
       FIG. 3  is an illustration of the web cartridge and drip dispenser in accordance to an embodiment. A web material  210  is nipped against the fuser roll  462  such that PDMS fuser oil is dripped onto web by the metering channel  230 . The shown metering channel  230  can be made from existing hollow copper tube (a DC8000 fuser component) with evenly spaced apertures or holes. The PDMS is used with a syringe pump to deliver the oil into the metering channel  230  positioned above the web material  210 . The holes in the tube are at the top of the metering channel  230  and the ejected oil flows around the outside of the channel and drops from the bottom of the channel. The cleaning agent does not drop directly from the holes but after it diffuses on the lower skin of the channel. In the illustrated figure the oil drops onto the tension bar  232  of a tension bar mechanism to help with even spreading of the fuser oil, although the tension bar  232  could be placed in a variety of different locations closer or further from the nip. 
       FIG. 4  is a side view of the web cartridge employing a one event cleaning agent strategy  300  in accordance to an embodiment. The web cartridge  310  contains a supply roll  330  holds virgin web material  210  that is moved towards take-up roll through pressure roll  322  and pressure roll  320  until its is wound around take up roll  335 . A motor (not shown) may drive the take up roll  335 , causing the fuser cleaner web or web material  210  to move from the supply roll  330  in the direction of arrow  365 , to come into contact with the fuser roll  462 , and then to move in the direction of arrow onto the take up roll  335 . A plurality of pressing rollers such as pressing roller  325  ensures that a controlled wrap exists between web material  210  and the pressure roller  322  and can in some instances be equipped with an encoder disc on its axis for use in measuring and for use in a feedback loop for a control system for controlling the velocity of the web material  210 . 
       FIG. 4  illustrates a one event cleaning agent strategy where the agent is dispensed or dripped  360  by the metering channel  350  on the web material  210  when is at pressure roller  320  and immediately prior to contact with the fuser roll  462 . 
       FIG. 5  is a side view of the web cartridge employing a two event cleaning agent strategy  400  in accordance to an embodiment. The web cartridge  310  contains a supply roll  330  holds virgin web material  210  that is moved towards take-up roll through pressure roll  322  and pressure roll  320  until its is wound around take up roll  335 . A motor (not shown) may drive the take up roll  335 , causing the fuser cleaner web or web material  210  to move from the supply roll  330  in the direction of arrow  365 , to come into contact with the fuser roll  462 , and then to move in the direction of arrow onto the take up roll  335 . A plurality of pressing rollers such as pressing roller  325  ensures that a controlled wrap exists between web material  210  and the pressure roller  322  and can in some instances be equipped with an encoder disc on its axis for use in measuring and for use in a feedback loop for a control system for controlling the velocity of the web material  210 . 
     In the two event cleaning agent strategy the agent is dispensed or dripped  460  by the metering channel  450  on the web material  210  before pressure roller  322  and immediately prior to contact with the fuser roll  462 . In this scenario the fuser roller  462  is exposed to the cleaning agent at two points as opposed to at one point with the one event strategy outlined above with reference with  FIG. 4 . 
       FIG. 6  illustrates oil-on-copy as a function of oil-drip speeds in accordance to an embodiment. Print runs up to 100 consecutive sheets at web speed of 1.4 mm/min using an oil drip rate of 0.8 mL/min and 1.5 mL/min were measured for oil-on-copy. The oil-on-copy metric captures the amount of oil on and in the substrate post-fusing. While there is some variability it is notable that the bulk of the samples at 0.8 mL/min rate were on the average less than 2 mg/copy and that when the oil drop rate was increased the amount of oil on the final substrate was also increased most being on the average between the range of 1-3 mg/copy. The metric for the 0.8 mL/Min is illustrated by function  610  and the 1.5 mL/Min by function  620 . 
     It will be appreciated that various of the above-disclosed and other features and functions, or alternatives thereof, may be desirably combined into many other different systems or applications. Also that various presently unforeseen or unanticipated alternatives, modifications, variations or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the following claims. 
     The fuser oil applicator offers advantages to the convention pre-saturated web because it facilitates the removal of a complicated and expensive removal agent management (RAM) system with the replacement of a metering channel dispenser directly onto fuser roll. Further, the fuser oil applicator offers low amounts of oil transferred from fuser roll to substrate surface (around 0.5-3 mg/copy) to mitigate post-finishing issues such as excess fuser oil lingering on print surface. Further, since oil-recycling is not required there is no sump pump for contamination and since web materials are wound up and oil or contaminate materials such as wax and toner are retained in the spent web cartridge it provides a mechanism for easy removal and negates the need for complicated machinery. No streaking of oil was observed on print surfaces with oil on copy from 0.5-3 mg/8.5×11 (Letter) copy. 
     Although the illustrated embodiment relates to xerographic fusing, the invention can be used in other printing technologies, and the like. It is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art. Accordingly, the preferred embodiments of the invention as set forth herein are intended to be illustrative, not limiting. Various changes may be made without departing from the spirit and scope of the invention as defined in the following claims.