Patent Document

FIELD OF THE INVENTION  
         [0001]    The present invention relates to cleaning apparatus for rollers found in feeding systems for paper. More specifically, the present invention relates to cleaning anti-offset agents that can contaminate rollers, such as feed rollers and retard rollers, when feeding systems are used for glossy paper.  
         BACKGROUND OF THE INVENTION  
         [0002]    Feeder systems, such as paper feeders, can be found in a variety of mechanical systems. For example, feeders are often used in photocopiers, fax machines, computer printers, printing presses, and mail handlers. A specific example of a sheet feeder is the F350 manufactured by Pitney Bowes Inc. (Shelton, Conn.). The primary purpose of these feeders is to take a stack of paper (or other types of stackable media), separate one sheet from the balance of the stack, and apply the separated sheet to another mechanical device. The feeder has to be flexible enough to handle a variety of types of paper. For example, the paper may be of mixed sizes such as letter-size, legal size, or A4 size. The paper may also be of a variety of weights depending on the percentage of cotton used therein. Furthermore, these papers may be covered by different coatings and inks.  
           [0003]    From time to time, the rollers may become contaminated with dust or dirt. This causes the rollers to lose their efficacy and misfeeds or multifeeds result. A mechanical cleaner can be used to clean the rollers. For example, in the F350, the cleaning apparatus is a block of urethane elastomer with lateral slots cut into it to form a series of elastomericblades which contact the roller.  
           [0004]    Increasingly used today are papers having a glossy coating. This type of paper is often used in lithography and flexography. Ink may smear or offset, because the glossy coatings on these papers have slower drying times. To solve this problem, the printer treats the paper with anti-offset agents such as anti-offset spray, a finely dispersed powder of calcium carbonate, starch, or sugar. These anti-offset agents prevent the freshly printed image from transferring to adjacent sheets when stacked at the output of the printing machines. Although these powders and sprays enhance the printing process, they cause problems when the printed glossy sheets of paper are subsequently fed through a feeder apparatus. This is because the anti-offset agents lift off the paper and contaminate the individual components of the feeder. As with dust and dirt, these agents will cause, for example, two or more sheets to be fed through the feeder instead of a single sheet due to contamination of the feeder&#39;s retard element. Another problem is that the glossy sheet will not feed through the feeder at all due to contamination of the feed roller.  
           [0005]    The cleaning apparatus of the F350, although effective for dust and dirt, is ineffective to remove anti-offset agents because there is not enough abrasion between the soft elastomeric blades and the roller.  
           [0006]    One current solution to the anti-offset agent build-up problem includes shutting down the feeder system and manually cleaning the components. This adds extra physical labor from an operator as well as a time delay in the operation of the feeder. Another solution is to attach a separate cleaning apparatus to the feeder when the feeder is not in operation. See, for example, U.S. Pat. No. 4,843,436 which teaches the use of a separate feed roll cleaner to clean the feeder system when the feeder system is not in operation. Although this solution does not require extensive physical labor, the runtime of the feeder system is reduced if it has to be periodically shut down in order to be cleaned.  
           [0007]    Thus, a need exists for a cleaning apparatus that can continuously clean the feeder system without the need for the feeder system to be shut down. Moreover, there is need for a cleaning apparatus that minimizes the need for human intervention in the cleaning of the feeding apparatus.  
         SUMMARY OF THE INVENTION  
         [0008]    In one aspect, the present invention features a cleaning apparatus for a feeder system having a chassis and roller. The apparatus includes a blade contact force component; a blade responsive to the blade contact force component, the blade having an edge locatable against the roller by a contact force applied by the contact force component; and a supporting arm having a fixture end and a mounted end. The fixture end of the supporting arm is attached to the cleaning blade and the mounted end is connected to the chassis of the feeder system. In one embodiment, the contact force applied by the blade contact force component can range from about 0.01 to about 0.13 N/mm.  
           [0009]    In another aspect, the present invention features a cleaning apparatus with a cleaning head having abrasive particles affixed thereto and in contact with the roller and a supporting arm having a fixture end and a mounted end, the fixture end attached to the cleaning head and the mounted end connected to the chassis of the feeder system. In one embodiment, the cleaning head is a mesh. The mesh can be an abrasive open screen from about 100 to about 200 grit. In another embodiment the cleaning apparatus further comprises a force component interposed between the support arm and the chassis of the feeder system from about 0.01 to about 0.13 N/mm.  
           [0010]    In another aspect, the present invention features a cleaning apparatus that includes a cleaning head contact force component, a cleaning head having abrasive particles affixed thereto, and a supporting arm having a fixture end and a mounted end, the fixture end attached to the cleaning head and the mounted end connected to the chassis of the feeder system. The cleaning head has a side locatable against the roller applied by the cleaning head contact force component.  
           [0011]    In yet another aspect, the present invention features cleaning apparatus specifically for use with a system that feeds sheets of glossy paper.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]    The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate a presently preferred embodiment of the invention, and together with the general description given above and the detailed description of the preferred embodiment given below, serve to explain the principles of the invention:  
         [0013]    [0013]FIG. 1 is a schematic side view of a feeder system used for feeding a stack of paper;  
         [0014]    [0014]FIG. 2 is a schematic side view of a feeder system using a cleaning apparatus of the present invention with a feed roller;  
         [0015]    [0015]FIG. 3 is a schematic side view of a feeder system using a cleaning apparatus of the present invention with an active retard roller;  
         [0016]    [0016]FIG. 4 is a chart depicting the misfeeds of the feeder system as a function of the cleaning head configuration used on a feed roller feeding glossy printed sheets therein; and  
         [0017]    [0017]FIG. 5 is a chart depicting the wear and misfeed rates of the feeder system as a function of the cleaning head configuration used therein. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0018]    Description of Feeder System  
         [0019]    [0019]FIG. 1 shows a feeder system  100  known in the art used to feed sheets of paper. The chassis  102  defines the structural framework of the feeder system  100  and has a plurality of connection points, for example  104 ,  105 , and  106 . Retard pad arm  108  has a back end  110  and a front end  112  opposite thereto. Retard pad arm  108  also has a top side  114  and an aperture  116  located slightly past the midpoint of retard pad arm  108  towards the back end  110 . Arm spring  118  is a force component having an arm attachment end  120  threaded through aperture  116  and a chassis attachment end  122  mounted to connection point  106  of chassis  102 . Retard pad  124  has a trapezoidal cross-section defining a straight side  126 , an angled side  128 , top surface  130 , and a bottom surface  131 . The retard pad  124 , at bottom surface  131 , is fixed to the top side  114  of the retard pad arm  108  with the angled side  128  of retard pad  124  oriented towards the front end  112  of the retard pad arm  108 . The angle of the angled side  128  of retard pad  124 , from the front end  112  towards the back end  110  of retard pad arm  108 , is about 80°. A feed roller  132  has a roller surface  134  and is mounted through its longitudinal axis to an axle  136  that drives the feed roller  132  in a counterclockwise rotation. The surface  134  of the feed roller  132  contacts the top surface  130  of the retard pad  124  along a line tangent to roller surface  134 , the nip  138 . A feed tray  146  has an upper side  148  and lower side  150 . The feed tray  146  is of comparable dimension to the stack of paper  140  being fed. The stack of paper  140  sits on top of the upper side  148  of the feed tray  146 . Tray spring  152  is a force component having a fixing end  154  and a securing end  156  and opposite thereto. The fixing end  154  connects the tray spring  152  to the lower side  150  of the feed tray  146 . The securing end  156  is attached to the connection point  105 . A stack of paper  140  with a lead sheet  142  has a forward end  144  that is in contact with the angled side  128  of the retard pad  124 . The lead sheet  142  touches the roller surface  134  of the feed roller  132 . The lead sheet  142  is fed through the nip  138 .  
         [0020]    The two springs identified in the system, the arm spring  118  and tray spring  152 , generate the forces F n  and F s , respectively. The coefficients of friction can be identified in the feeder system  100 . Between the roller surface  134  of the feed roller  132  and the lead sheet of paper  142  is μ roller-paper . Between the lead sheet of paper  142  and the balance of the stack of paper  140  is μ paper-paper . A driving force, which is the μ roller-paper *(F n +F s ), is responsible for feeding the lead sheet of paper  142  though the nip  138 . Opposing the driving force is the retard force, which is the μ paper-paper *(F s +μ paper-retard )*F n . In normal operation, the driving force exceeds the retard force causing the stack of paper  140  to be fed through the feeder system  100 . If the driving force is too low, then misfeeds can result on the stack of paper  140  or at the nip  138 .  
         [0021]    In the printing industry, glossy paper is commonly coated with a spray or powder (“anti-offset agents”) that prevents the printed images from being offset (i.e., smearing or smudging). When these glossy sheets of paper are fed through the feeder system  100 , the anti-offset agents transfer from the glossy sheets of paper to the roller surface  134  of the feed roller  132 .  
         [0022]    For example, when glossy paper that has anti-offset powders is used in the feeder system  100 , the anti-offset powders rub off the lead sheet of paper  142  and transfer to the roller surface  134  of the feed roller  132 . Such anti-offset powders include starch, sugar or calcium carbonate. Thus, the roller surface  134  becomes contaminated by developing a layer of anti-offset agents resulting in a decrease in the coefficient of friction μ roller-paper . When this occurs, the driving force is also reduced proportionally. The driving force will continuously decrease on each successive sheet of paper fed through because of the accumulation of anti-offset agents. At a certain point, the driving force will be less than the retarding forces, and consequently the feed roller  132  will fail to advance the sheet. Thus, the need exists for a cleaning apparatus that could constantly function while the feeder system is in operation to maintain the existing coefficient of friction.  
         [0023]    Feeder System with Cleaning Apparatus for a Feed Roller  
         [0024]    [0024]FIG. 2 shows a feeder system  200  known in the art with a chassis  202  that defines the structural framework of the feeder system  200  and has a plurality of connection points, for example  204 ,  206 ,  208 ,  210 , and  212 . Retard pad arm  214  has a back end  216  and a front end  218  opposite thereto. Retard pad arm  214  also has a top side  220  and an aperture  222  located slightly past the midpoint of retard pad arm  214  towards the back end  216 . Arm spring  224  is a force component having an arm attachment end  226  threaded through aperture  222  and a chassis attachment end  228  mounted to connection point  206  of chassis  202 . Retard pad  230  has a trapezoidal cross-section defining a straight side  232 , an angled side  234 , top surface  236 , and bottom surface  237 . The retard pad  230 , at bottom surface  237 , is fixed to the top side  220  of the retard pad arm  214  with the angled side  234  oriented towards the front end  218  of the retard pad arm  214 . The angle of the angled side  234  from the front end  218  towards the back end  216  of retard pad arm  214 , is about 80°. A feed roller  238  has a roller surface  240  and is mounted through its longitudinal axis to an axle  242  that drives the feed roller  238  in a counterclockwise rotation. The roller surface  240  of the feed roller  238  contacts the top surface  236  of the retard pad  230  along a line tangent to roller surface  240 , the nip  244 . A feed tray  252  has an upper side  253  and lower side  254 . The feed tray  252  is of comparable dimension to the stack of paper  246  being fed. The stack of paper  246  sits on top of the upper side  253  of the feed tray  252 . Tray spring  255  is a force component having a fixing end  256  and a securing end  257  opposite thereto. The fixing end  256  connects the tray spring  255  to the lower side  254  of the feed tray  252 . The securing end  257  is attached to the connection point  208 . A stack of paper  246  with a lead sheet  248  has a forward end  250  that is in contact with the angled side  234  of the retard pad  230 . The lead sheet  248  touches the roller surface  240  of the feed roller  238 . The lead sheet  248  is fed through the nip  244 .  
         [0025]    A cleaning apparatus  260  has a cleaning arm  262  and cleaning head  264 . The cleaning arm  262  has an anterior end  266  and a posterior end  268  opposite the anterior end  266 , a side facing the roller  270 , a side remote from the roller  272 , and a hole  274  located in between the midpoint of the cleaning arm  262  and the posterior end  268 . A pivot  276  connects the posterior end  268  to the connection point  210  of the chassis  202 . The cleaning head  264  has an abrasive side  278  and is connected to the side facing the roller  270  near the anterior end  266  by a hinge  280 . The abrasive side  278  is in contact with the roller surface  240  of the feed roller  238 , and forms the angle α with the tangent line  279 . An attachment spring  282  having a cleaning arm-attaching end  284  and a frame-attaching end  286  provides force to abut cleaning head  264  of cleaning apparatus  260  against roller surface  240  of feed roller  238 . The cleaning arm-attaching end  284  of attachment spring  282  is threaded through the hole  274  of the cleaning arm  262 . The frame-attaching end  286  of attachment spring  282  is fixed to the connection point  212 .  
         [0026]    The cleaning head  264  can be any type of abrasive fixture that could clean the feed roller  238 . Fixtures include, but are not limited to, sanding sheets, beater bars and wire brushes. Preferable fixtures are blades and meshes.  
         [0027]    In one embodiment of the present invention, the cleaning head  264  is chosen to be a metal blade. The metal blade has a sharpened edge that serves as the abrasive side  278 . If a blade is used for the cleaning head  264 , then the blade is preferably made of hardened metal resistant to wear. Metal is more effective in removing the anti-offset agents than other materials, such as urethane, an elastomer. Most preferably is for the metal blade to be made of hardened steel with a square ground edge. It is believed that the blade scrapes the anti-offset agents from small crevices that may develop in the roller surface  240  of a feed roller  238 . A soft urethane blade would yield to the curvature of the feed roller  238 . A metal blade would be hard and strong enough to push into the feed roller  238  and scrape off the anti-offset agents. As the blade scrapes across the roller surface  240 , the roller surface  240  substantially deforms and small pieces of the feed roller  238  tend to be stretched. As the feed roller  238  continues to rotate on the axle  242 , the stretched surface snaps back to its original configuration which causes the anti-offset agents to flick off the roller surface  240 . Additionally, the roller surface  240  is worn down by the blade from the abrasion. While the above is believed to be the mode of operation of the present invention, the inventors do not intend to be held to any specific hypotheses regarding the functionality of the present invention.  
         [0028]    When using a blade as the cleaning head  264 , angle a preferably is an acute angle, specifically ranging from about 0° to about 60°. More preferably, α is about 15°. The hinge  280  connects the cleaning head  264  to the cleaning arm  262 . The attachment spring  282  provides the load to keep the cleaning head  264  constantly in contact with the roller surface  240 . The load produced by the attachment spring  282  can preferably range from about 0.011 N/mm to about 0.13 N/mm. For example, if the feed roller  238  has a width of 40 mm, then the load would range from about 0.5N to about 5N. A force of about 0.6 N is preferable for use with a 40 mm width feed roller (0.015 N/mm)  238 . Any type of component that could provide the requisite load can be substituted for the attachment spring  282 . For example, the cleaning arm  262  can be mounted in such a manner that would provide the constant load.  
         [0029]    In another embodiment of the invention, is use of an abrasive mesh as the cleaning head  264 . The abrasive mesh is an open screen with bonded adhesive particles. When using the abrasive mesh, the angle a can range from about 0° to about 60°. More preferably, α is about 0° tangent to the feed roller  238 . The face of the mesh with the bonded adhesive particles serves as the abrasive side  278 . The mesh of the open screen can range from about 100 grit to about 200 grit. The abrasive mesh can be loaded against the feed roller  238 . The proper load can range from about 0.011 N/mm to about 0.13 N/mm of the width of the feed roller  238 . For example, if a feed roller  238  with a width about 40 mm was used, then the load of the cleaning head  264  would be 0.5 N to about 5 N.  
         [0030]    Feeder System with Cleaning Apparatus for a Retard Roller  
         [0031]    [0031]FIG. 3 shows a feeder system  300  with an active retard roller in lieu of a retard pad used to feed sheets of paper. The chassis  302  defines the structural framework of the feeder system  300  and has a plurality of connection points, for example  304  and  306 . Retard roller arm  308  has a back end  310  and a front end  312  opposite thereto. Retard roller arm  308  also has a top side  314 , a spring attachment point  316 , a cleaner arm pivot point  318 , and an aperture  320  located slightly past the midpoint of retard roller arm  308  towards the back end  310 . Two C-shaped bushings  322  with their open ends oriented in the direction of the front end  312  are mounted to the top side  314  of the retard roller arm  308 . A shaft  324  is inserted within the C-shaped bushings  322 . A retard roller  326  having an integral gear  328  rotates in a counterclockwise rotation on the shaft  324 . The bushings  322  are designed such that the retard roller  326  can be easily replaced. The integral gear is driven by a gear motor  330  in communication with a pinion  332 . A feed roller  334  is in contact with the retard roller  326 . The feed roller  334  is driven in a counterclockwise rotation by separate mechanics.  
         [0032]    Arm spring  336  is a load force component having an arm attachment end  338  threaded through aperture  320  and a chassis attachment end  340  mounted to connection point  306 .  
         [0033]    A cleaning apparatus  342  has a cleaning arm  344  and cleaning head  346 . The cleaning arm  344  has an anterior end  348  and a posterior end  350  opposite the anterior end  348 , a side facing the roller  352 , a side remote from the roller  354 , and a hole  356  located in between the midpoint of the cleaning arm  344  and the posterior end  350 . A pivot  360  connects the posterior end  350  to cleaner arm pivot point  318  of the retard roller arm  308 . The cleaning head  346  has an abrasive side  362  and is connected to the side facing the roller  352  near the anterior end  348  by a hinge  364 . The abrasive side  362  is in contact with the retard roller  326 . A retard arm attachment spring  366 , having a cleaning arm-attaching end  368  and a frame-attaching end  370  provides force to abut cleaning head  346  of cleaning apparatus  342  against the surface of retard roller  326 . The cleaning arm-attaching end  368  of retard arm attachment spring  366  is threaded through the hole  356  of the cleaning arm  344 . The frame-attaching end  370  of retard attachment spring  366  is fixed to the spring attachment point  316 .  
         [0034]    A feeder system  300  can have as many cleaning apparatus  342  as there are rollers. For example, a cleaning apparatus  342  can be provided for the feed roller and the retard roller. By having multiple cleaning apparatus, the maintenance of the feeder system  300  is minimized because the rollers are constantly being kept clean. If only one is used on a cleaning apparatus  342 , then, the machine may still experience misfeeds and multi-feeds. Other feeder systems such as corner-buckle separators, may only require a cleaner to operate reliably.  
         [0035]    Experimental Results to Determine Performance of Various Cleaning Heads  
         [0036]    Experiments were conducted to determine the efficacy of various types of cleaner heads  264  used in the cleaning apparatus  260  as shown in FIG. 2. The optimal cleaning head  264  cleans the feed roller  238  without reducing the life of the feed roller  238  below an acceptable limit, for example about 50,000 cycles.  
         [0037]    A F350 commercial feeder (available from Pitney Bowes, Shelton, Conn.) was configured with the cleaning apparatus  260 . Glossy paper coated with anti-offset powders at high concentrations was fed through the F350 commercial feeder, print side up. The test called for a maximum of 2,000 cycles to be run or until at least five failures (i.e., misfeeds or multifeeders) were observed.  
         [0038]    Seven configurations of cleaning heads  264  were tested. They were as follows:  
         [0039]    1. 120 grit abrasive mesh tested at 2.22 N (tested at 0.06 N/mm)  
         [0040]    2. 180 grit abrasive mesh tested at 2.44 N (tested at 0.06 N/mm)  
         [0041]    3. A square ground edge, hardened steel abrasive blade at a 15° angle tested at 2.22 N (tested at 0.06 N/mm)  
         [0042]    4. 34 mm fiber length wire brush (manufactured by Felton) with the fibers being 0.11 mm in diameter and spaced at approximately 40 ends/mm  
         [0043]    5. 8.5 mm fiber length wire brush (manufactured by Felton) with the fibers being 0.11 mm in diameter and spaced at approximately 40 ends/mm  
         [0044]    6. tacky roller (manufactured by Rotadyne) that is made from a naturally tacky elastomer  
         [0045]    7. orange cleaning sponge (available from Block New England) configured as a roller  
         [0046]    The results indicated that the abrasive blade and meshes exhibited the best performance. The tacky roller had to be cleaned itself after every 2,000 sheets. The 8.5 mm fiber length wire brush did function comparably to the metal blade; however, the performance of the brush was unacceptable because it cut grooves into the feed roller  238 . As for the 34 mm fiber length wire brush, the length of the fibers made them too unabrasive to be effective as a cleaning apparatus  260 . Although after cleaning, the tacky roller still functioned well as a cleaning apparatus, the constant need for cleaning the tacky roller rendered this option less than optimal in a commercial setting. The orange cleaning sponge performed poorly because the integrity of the sponge would disintegrate upon use, generating debris.  
         [0047]    Charts of the results from the experiment are shown in FIGS. 4 and 5.  
         [0048]    [0048]FIG. 4 shows the number of misfeeds as a function of cleaner head configuration. As a control, the F350 feeder was run without a cleaning apparatus. Only 450 sheets of glossy paper could be fed until a misfeed was encountered. As FIG. 4 shows, any type of cleaning apparatus was better than nothing; however, abrasive cleaners are superior. The 120 grit abrasive mesh, 180 grit abrasive mesh, and abrasive blade all performed well. The 8.5 mm fiber length wire brush would have been acceptable if the feed roller  334  did not develop grooves.  
         [0049]    [0049]FIG. 5 illustrates any trends in feed roller  334  wear and performance. The wear of the feed roller  334  is plotted as the diameter reduction in mm per thousand feeds. The performance of the feed roller  334  is expressed as the average number of feeds before a misfeed occurs (i.e., misfeed rate). From this data, a measurable diametral wear rate of at least 0.1 mm/thousand feeds is required to allow the feeder system  200  to operate reliably. In reading FIG. 5, note that while no measurable diameter reduction was noted for the 8.5 mm fiber length wire brush, grooves were worn into the feed roller  334  indicating volume loss.  
         [0050]    It is understood that while the invention has been described in conjunction with the detailed description thereof, that the foregoing description is intended to illustrate and not limit the scope of the invention, which is defined by the scope of the appended claims. Other aspects, advantages, and modifications are within the claims.

Technology Category: 7