Abstract:
Toner xerographically adhered to a material, such as a sheet of paper, may be removed using a solvent-based or solventless approach. The application of ultrasonic tamping, scraping and brushing may aid in removing toner particles. In a solvent-based approach, a solvent may be applied generally or the solvent may be targeted specifically to the toner covered portions of the material to loosen the adhesive securement of the toner to the material. Thereafter, the toner is subjected to a mechanical abrasion using ultrasonic and physical agitation to cause flaking of the toner.

Description:
BACKGROUND 
     This invention relates generally to removing toner from xerographically printed material. 
     In conventional xerographic printing or copying processes, a light image of an original to be copied is recorded in the form of an electrostatic latent image. The electrostatic latent image is formed on a photosensitive member and the latent image is subsequently rendered visible by the application of electroscopic thermoplastic resin particles commonly called toner. 
     The photosensitive member is charged and then exposed to light from a laser or light emitting diode to form the electrostatic latent image. The electrostatic latent image is developed by bringing a developer mixture into contact therewith. A dry or wet development procedure may be utilized. A dry developer mixture usually provides carrier granules having toner particles adhering triboelectrically thereto. Toner particles are attracted from the carrier granules to the latent image forming a toner powder image thereon. 
     After the toner particles have been deposited on the photosensitive member, in the configuration of the image, the toner particles are transferred to a copy sheet by the application of pressure or an electrostatic force. In some cases, the developed image may be transferred to an intermediate transfer member and thereafter transferred to the copy sheet. 
     After the transfer of the developed image is completed, the copy sheet advances to a fusing station that may include a fuser roll and a pressure roll. The developed image is then fused to the copy sheet by pressing the copy sheet between fusing and pressure rolls, thereby forming a permanent image. The attachment of the toner to the paper is primarily due to an adhesive, included in the toner, that adhesively secures the toner to the paper upon the application of pressure and/or heat. 
     A very large number of sheets of paper are run through printers. Many of these printed pages are never used and the paper is simply either discarded or sent for recycling. In many businesses, the amount of paper that is wasted in this way, never to be used, is staggering. It is estimated that about twenty percent of the documents that are printed are immediately thrown away. A large percentage of the remaining paper is also eventually thrown away without being substantially wrinkled, written on or otherwise disrupted. 
     Thus, there is a need for a better way to reuse printed material. 
     SUMMARY OF THE INVENTION 
     One embodiment of the present invention includes a method of removing toner from a material comprising: applying a solvent to the toner to weaken the adhesive attachment of the toner to the material; and subjecting the toner to ultrasonic scraping. 
     Another embodiment of the present invention includes a method of removing toner from a material comprising: applying ultrasonic energy to the material by applying an ultrasonic tamping force to the material; and removing the toner from the material. 
     Yet another embodiment of the present invention includes a method of removing toner from the material comprising: identifying the location of the toner on the material; preferentially applying a chemical that removes toner to the locations where the toner is present on the material; and attacking the bond between the toner and the material to remove the toner. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a schematic depiction of one embodiment of the present invention; 
     FIG. 2 is a schematic depiction of another embodiment of the present invention; 
     FIG. 3 is a schematic depiction of still another embodiment of the present invention; 
     FIG. 4 is an enlarged, vertical cross-sectional view of the embodiment shown in FIG. 3; and 
     FIG. 5 is a schematic depiction of still another embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION 
     Referring to FIG. 1, a deprinter  10  may receive a sheet of paper indicated as A. The sheet A has xerographic printing on its lower side. While a sheet of paper A is illustrated, any xerographically printed material may be processed including paper rolls and plastic film materials. The sheet A enters a tank  12  filled with a suitable solvent pursuant to a wet process embodiment. A suitable solvent may be one which preferentially attacks the adhesive securing the printing toner to the paper rather than dissolving the toner itself. Examples of suitabley solvents include members of the organic sulfone or sulfoxide families including dimethyl sulfoxide ((CH 3 ) 2 SO). 
     The sheet A may be advanced to the position indicated at B wherein it is immersed in the bath of a suitable solvent. The adhesion of the toner to the paper is interrupted by the solvent without adversely affecting the paper or the used toner. 
     An ultrasonic tamper  17  may be utilized to loosen the toner from the paper. The tamper  17  may include a V-shaped head that is ultrasonically reciprocated towards and away from the paper to hit or tamp the paper to loosen the toner. The tamper  17  micro bends the paper. Since the toner is more brittle than the paper, the toner starts to flake off of the paper. Sets of rollers  14   a  and  14   b  may tension the paper and further cause the toner to be broken into flakes. 
     In addition, an ultrasonic scraper  18  may be utilized to remove any flakes of toner particles. The scraper  18  may include a sharp edged, obliquely aligned, rigid member that is ultrasonically agitated to scrape the toner from the paper. The member may be made of metal or damped resonant material such as sapphire, as two examples. 
     Similarly, a stiff rotary brush  20  may be rotated against the printed surface of the sheet B to remove any remaining toner flakes. 
     The solvent in the tank  12  may be subjected to continuous filtering in a filter  24  and drying in a dryer  26  to remove water that may be absorbed by the solvent. A pair of squeeze rolls  22  may be utilized to remove any remaining solvent. 
     Thereafter, the sheet, indicated at C, may be subjected to solvent recovery by causing the sheet to ride over a rotating vacuum drum  28  in a solvent recovery stage  24 . The sheet C may be pressed against the vacuum drum  28  through the operation and positioning of the squeeze rolls  22 . 
     Referring next to FIG. 2, a deprinter  10   a  pursuant to semi-wet process may involve the use of a solvent vapor, such as dimethyl sulfoxide vapor, to facilitate the removal of the fused toner. Solvent filtering and recovery may be unnecessary. 
     In this embodiment, a vapor drum  32  is provided within a housing  30 . A paper sheet indicated as D, may be advanced into the housing  30  where it assumes the position indicated at E. The vapor drum  32  creates a fog, mist or airborne suspension of solvent, using ultrasonic techniques for example. The fog or mist may also be formed by heating, nebulizing, spraying or other techniques. 
     The sheet E then may be subjected to ultrasonic tamping by the tamper  17  and ultrasonic scraping by the scraper  18 . Finally, the sheet E may be subjected to brushing using the rotary brush  20 . 
     The sheet E then may be passed through rollers  22  into a solvent purge housing  24 . The solvent purge housing  24  may include a rotating vacuum drum  28 , situated between a pair of rollers  22 , to remove as much of the solvent as possible from the sheet, indicated now at F. 
     Turning next to FIG. 3, a dry process may use a pair of stages  34  and  24 . A sheet G is enters the stage  34 . The sheet, in the position H, is subjected to a spray of a suitable solvent from the sprayer  36 . The solvent may be sprayed onto the paper to remove the fused toner. The solvent may attack the adhesive that secures the toner to the paper and may be the same type of solvent described previously. 
     The solvent may be sprayed in very small micro quantities using a thermal spray head  41  for example of the type used in ink jet printers. To reduce the use of solvent, optical cameras or sensors  37  may be placed on the spray head. The sensors  30  develop signals so that the solvent is only sprayed where the toner is detected. The spray head  41  may be mounted on a support  40  for sliding movement along the width of the sheet H so that a sensor  37  senses the nature of the printing on the sheet  14  before the spray head  41  arrives at the sensed location. 
     Thereafter, the same tamping, scraping and brushing processes may be undertaken using the ultrasonic tamper  17 , ultrasonic scraper  18  and rotary brush  20  in one embodiment. In a final stage  24 , the solvent is purged, for example, using the techniques described previously or the solvent is otherwise chemically neutralized. 
     Referring to FIG. 4, the spray nozzle  41  may ride on a tubular support  40  along a bar  38  to enable it to reciprocate along the width of the sheet of paper indicated as H in FIG. 3 in the direction of the arrows in FIG.  4 . The spray solvent indicated as L may be directed precisely at the toner so that solvent is not wasted by spraying it over the entire sheet. 
     Referring finally to FIG. 5, in accordance with still another embodiment, a solventless process may be utilized that relies on ultrasonic tampers  17  and scrapers  18  along with a sticky silicone or rubber drum  46 . The paper J is caused to enter the housing  42 . The paper, in the position indicated at K, is subjected to a series of tamping, scraping and brushing stages in suitable repetition to break up the toner into flakes and to loosen or remove those flakes. In this case, a series of tamping stages may use a tamper  17  followed by a scraper  18  and a rotary brush  20 . 
     A sticky surfaced rotating drum  46  in a stage  44  removes the loosened toner. The drum  46  is continuously cleaned and dressed with new adhesive, using a scraper/applicator  48  to maintain a sticky adhesive surface that removes the loosened toner from the paper. 
     While the present invention has been described with respect to a limited number of embodiments, those skilled in the art will appreciate numerous modifications and variations therefrom. It is intended that the appended claims cover all such modifications and variations as fall within the true spirit and scope of this present invention.