Toner Reclaiming System For Electrostatic Printing Machines

Abstract

A toner powder reclaiming system for use in conjunction with a photoreceptor cleaning device in an electrostatic reproduction machine, the system including a particle separator in the path of movement of air flow containing toner particles and defined by ducts arranged to receive the particles from the cleaning device. After the toner particles have become separated, they are directed to a plurality of receptacles, may be removed from the machine and used to return the toner particles back into the machine for reuse.

Description

This invention relates to particle reclaiming systems, and particularly to a toner reclaiming system that is particularly adapted for use with automatic copiers/reproducers capable of high speed operation.

As is well known in recent years, the steadily increasing need and use of visual communications has required an enormous increase in the amount of paper work that must be accomplished, maintained and made available for wide circulation. Present day commercial automatic copiers/reproduction machines for this purpose are adapted to produce copies of between 10 and 60 sheets of copy per minute and are capable of effecting solid area development. Enormous amounts of developing material are consumed during long run productions and to a large extent a relatively large amount of some of this material is lost or diverted, requiring frequent additions of new material to the development system for the machines. Heretofore, there has been no effective way in which to recover residual toner collected or otherwise made available from a developing system and which will insure the opportunity to recover the toner particles for later use.

It is, therefore, the principal object of this invention to improve electrostatic reproduction machines by providing for the return of most of the residual developing material cleaned from a photoreceptor surface for reuse in the machines.

Another object of this invention is to reclaim toner particles previously removed from a photoreceptor surface in such a manner as not to damage the particles during the reclaiming process so that image quality is acceptable with the use of reclaimed particles.

These and other objects of this invention are obtained by an air flow system which carries air laden toner particles from a brush cleaning device in an electrostatic printing machine to a particle separation apparatus wherein the particles are separated and conveyed to a collection manifold and thence to collecting containers. Air continues along a path defined by another duct and out of the machine.

For a better understanding of the invention as well as other objects and further features thereof, reference is had to the following detailed description of the invention to be read in conjunction with the accompanying drawings wherein:

FIG. 1 is a schematic sectional view of a reproduction machine incorporating the present invention therein with the processing components in section to better illustrate the environment for the present invention;

FIG. 2 is a schematic view of a toner reclaiming system for the reproduction machine;

FIG. 3 is a partial schematic view, partly broken away, of a detail of the reclaiming system and

FIG. 4 is a cross-sectional view of the detail feature taken along the line 4--4 in FIG. 3.

For a general understanding of an electrostatic processing system in which the invention may be incorporated, reference is had to FIG. 1 in which some of the various systems components for the machine are schematically illustrated, and to FIG. 2 wherein the complete reclaiming system is shown. As in all electrostatic systems such as a xerographic machine of the type illustrated, a light image of an original to be reproduced is projected onto the sensitized surface of a xerographic plate to form an electrostatic latent image thereon. Thereafter, the latent image is developed with an oppositely charged developing material comprising carrier beads and smaller toner particles triboelectrically adhering thereto to form a xerographic powder image corresponding to the latent image on the plate surface. The powder image is then electrostatically transferred to a support surface to which it may be fixed by a fusing device whereby the powder image is caused permanently to adhere to the support surface.

The electrostatically attractable developing material commonly used in magnetic brush developing apparatus comprises a pigmented resinous powder referred to here as "toner" and a "carrier" of larger granular beads formed with steel cores coated with a material removed in the triboelectric series from the toner so that a triboelectric charge is generated between the toner powder and the granular carrier, and the toner is then attracted to the electrostatic latent image from the carrier bristles to produce a visible powder image on an insulating surface.

In the illustrated machine, an original D to be copied is placed upon a transparent support platen P fixedly arranged in an illumination assembly generally indicated by the reference numeral 10. While upon the platen, an illumination system flashes light rays upon the original thereby producing image rays corresponding to the informational areas on the original. The image rays are projected by means of an optical system 11 to an exposure station A for exposing the photosensitive surface of a moving xerographic plate in the form of a flexible photoconductive belt 12. In moving in the direction indicated by the arrow, prior to reaching the exposure station A, the portion of the belt being exposed would have been uniformly charged by a corona device 13 located at a belt run extending between a supporting roller 14 and a drive roller 15. The exposure station extends between the roller 14 and a third support roller 16.

The exposure of the belt surface to the light image discharges the photoconductive layer in the areas struck by light, whereby there remains on the belt a latent electrostatic image in image configuration corresponding to the light image projected from the original on the supporting platen. As the belt surface continues its movement, the electrostatic image passes around the roller 16 and through a developing station B located at a third run of the belt and in which there is positioned a developing apparatus generally indicated by the reference numeral 17.

The developing apparatus 17 comprises a plurality of magnetic brushes which carry developing material to the adjacent surface of the upwardly moving inclined photoconductive belt 12 in order to provide development of the electrostatic image. As the developing material is applied to the xerographic belt, toner particles in the development material are attracted electrostatically to the belt surface to form powder images.

The developed electrostatic image is transported by the belt 12 to a transfer station C located at a point of tangency on the belt as it moves around the drive roller 15 whereat a sheet of copy paper is moved at a speed in synchronism with the moving belt in order to accomplish transfer of the developed image. There is provided at this station a transfer roller 19 which is arranged on the frame of the machine for contacting the non-transfer side of each sheet of copy paper as the same is brought into transfer engagement with the belt 12. The roller 19 is electrically biased with sufficient voltage so that a developed image on the belt 12 may be electrostatically transferred to the adjacent side of a sheet of paper S as the same is brought into contact therewith.

There is also provided a sheet transport mechanism adapted to transport sheets of paper seriatim from a paper handling mechanism generally indicated by the reference numeral 23 to the developed image on the belt as the same is carried around the roller 15. A programming device operatively connected to the mechanism 23, and the illumination device for producing an electro-static latent image on the belt 12 is effective to present a developed image at the transfer station C in timed sequence with the arrival of a sheet of paper.

After the sheet is stripped from the belt 12, it is conveyed by a conveying system 24 into a fuser assembly generally indicated by the reference numeral 25 wherein the developed and transferred xerographic powder image on the sheet material is permanently affixed thereto. After fusing, the finished copy is discharged from the apparatus at a suitable point for collection externally of the apparatus.

The remaining or excess toner particles remaining as residue on the developed images, background particles and those particles otherwise not transferred are carried by the belt 12 to a cleaning apparatus 26 positioned on the run of the belt between the rollers 14, 15 adjacent the charging device 13. The cleaning device comprises a rotating brush 27, a corotron 28 for neutralizing charges remaining on the unused toner particles and a housing 30 for supporting the brush 27 and into which the toner particles are brought into an air stream to be conveyed away from the vicinity of the belt. For this purpose, the housing 30 is in communication with the input end 31 of a duct 32 which is connected to a vacuum apparatus and toner reclaiming system generally indicated by the number 33 for removing the toner laden air from the housing 30 on a continuing basis during machine operation.

The toner reclaiming system is in the form of an air conveying system including the duct 32 and input end 31 thereof, an output duct 34 having a filtering device 35 as the output end for the system, and an enlarged motor-driven blower or fan means 36 interimposed between and in operational communication relative to the ducts 32, 34. The blower may be of the conventional type having an impeller (not shown) mounted for rotation within a blower housing 37 having its input end connected to the duct 32 and its output end connected to the duct 34. The operation of the blower means is such as to move air from the chamber within the brush housing 30, through the duct 32; a separating means, the blower housing 37, the duct 34 and finally through the final filter 35 and out into the surrounding atmosphere.

Positioned in the duct 32, between its input end 31 and the blower 36 and operating as part of the air conveying system is a separating apparatus 40 which is utilized to separate the toner particles from the air flowing through the system. To this end, the separator 40 includes a housing 41 formed with an input fitting 42 to which the duct 32 is connected and an output fitting 43 to which a short duct 44, which is part of the main duct 32, connects the housing 41 to the input side of the blower housing 37. The separator 40 may be of any type which is adapted to separate particles from air flow and to permit the continued flow of the "clean" air while moving the particles to a collecting point. It is preferred that the separator be of the centrifugal type which is constructed so that particle-laden air is set in a whirling motion to drive the particles against walls by centrifugal forces.

The toner-free air flows through the housing 41 between walls within the housing, out of the housing by way of the fitting 43 and through the duct 44 into the blower housing 37. The entire movement of air is produced by the blower the discharged air being directed through the duct 34 and to the filtering device which is utilized in order to precipitate the remaining toner particles which may remain in the flow of air after leaving the separator 40.

As shown in FIGS. 3 and 4, one or more suitable openings 47 are formed in the end wall 52. Separated toner particles flow out of the openings and collect in a manifold 55 which may be suitably attached to the housing 41 as another separated chamber therein. The lower wall 56 of the manifold is formed with circular openings 57 disposed generally in a horizontal plane. Each of the openings is surrounded by a nozzle fitting 58 which may be inserted into a toner depositing receptacle or bottle 60. Alternately the openings 57 could also be an integral part of the manifold 55. In the illustrated arrangement, there are four nozzles 58 positioned at points of a square; that is, in two rows of two nozzles per row and each is provided with a bottle 60 of generally rectangular cross-sectional configuration. After the separated toner particles are delivered to the manifold, they flow through the nozzles 58 and thence into each of the four bottles 60. Generally, this depositing of particles in the bottles will be fairly even; that is, the bottles will receive particles in equal amounts.

Means are provided for supporting the four bottles 60 with the respective nozzles 58 in fairly air-tight relationship as shown in FIG. 3 and permit removal of the bottles individually. In FIG. 3, the bottles have their circular neck portions 61 surrounding the nozzles 58 in order to prevent outside air from leaking in the reclaiming system during its operation. The neck portions 61 are held in this operating position by means of a generally square-shaped plate 62 positioned below the nozzles 58 and formed by two, fairly wide, parallel slots defined by edges 63. The edges 63 of the slots are adapted to be slipped under each of the neck portions 61 and when the plate 62 is moved or forced upwardly, the neck portions and consequently, the bottles 60 are raised therewith and sealed against four nozzle-like openings in manifold 55.

Selective movement and locking into position of the plate 62 is provided by a spring means which normally maintains the plate 62 in its uppermost position and a lever-locking device which lowers the plate to disengage neck portions 61 of bottles from the nozzles 58 and permit the manual removal or installation of each of the bottles. The spring means comprises a pair of vertically positioned and parallel related guide pins 65, each slidably received in openings formed in bracket plates 66 which are secured to or form a part of the lower structure of the mainfold 55. A coil spring 67 encircles each of the pins 65 and extends between the bracket 66 and a pin head 68 formed at the upper ends of the pins. The lower ends 69 of the pins 65 project through suitable openings formed in the plate 62 and are locked thereat by suitable lock washers. The springs 65 are normally held in compression so that they maintain the plate 62 in its uppermost position as aforesaid. The springs and pins and their coacting structure are arranged symmetrically between the four bottles 60 so that the force on the plate 62 produced by the springs is fairly well balanced.

The lever-locking device comprises a manually actuable lever member 70 having a horizontally disposed element 71 positioned above the plate 62 and normal to the plane in which the pins 65 are positioned. The element is mounted for limited rotative movement by the lower structure of the manifold 55 and for this purpose, suitable aligned openings formed in opposed flanges 72 of the manifold are provided in order to rotatably receive the element 71. Lock washers may be used with the element and the flanges 72 in order to prevent axial movement of the lever 70.

A locking cam 73 is secured to the element 71 at a point between the pins 65, as shown in FIG. 4 and is engageable with the upper surface of the plate 62 at approximately the middle point thereof. A suitable handle 74 is provided on the lever 70 at an angle normal to the element 71 for permitting rotation of the element. In the position of the parts shown in FIG. 3, with the handle 74 in its uppermost position, the cam 73 is positioned out of engagement with the plate 62 thereby allowing the springs 67 to maintain the plate 62 in its uppermost position. This, in turn, forces the necks 61 of each of the bottles 60 up into sealed engagement with the respective discharge nozzles 58 of the manifold 55 and the toner reclaiming system is in condition for operation. A suitable spring lock device 75 mounted on the machine structure may be utilized to lock the lever 70 against movement which may cause lowering of the bottles 60.

In order to permit removal of the bottles 60 and/or the installation thereof, the toner reclaiming system must be placed in an inoperative condition, which obviously also requires the shutdown of the printing machine. The lever handle 74 is then activated downwardly or toward the viewer of FIG. 3 to the position indicated in FIG. 4. This movement would have rotated the cam 73 in the direction of the arrow, and to the final position shown in FIG. 4. In so moving, the plate 62 is forced downwardly against the bias of the springs 67 and, with the lobe of the cam having been moved over-center, the plate 62 becomes locked in the indicated position. The distance of movement of the plate is such as to produce disengagement of each of the necks 61 relative to the respective nozzles 58 and to provide a safe clearance therebetween for permitting manual removal of each bottle. In this position of the parts, each bottle may be individually slid out of their confining slots 63, emptied for reuse in the machine, and returned to its former position for additional reclaiming use.

As shown in FIG. 1, the developing apparatus 17 is provided with a toner dispensing device 76 which may be provided with an arrangement for feeding toner into the apparatus at various times depending upon the depletion of the toner particles in the developing material. The dispenser is provided with a bottle engaging flexible based fitting 78 having a suitable sealing cap 80 thereon for use when the fitting is not in use. Each of the bottles 60 when containing a sufficient quantity of toner particles may be operatively connected to the fitting 78, inverted and manually vibrated for pouring the particles in the dispenser for reuse. Preferably, the necks 61 and the fitting 78 are constructed so as one is a mate to the other in order to eliminate spillage or leakage.

While the invention has been described with reference to the structure disclosed, it is not confined to the details set forth but is intended to cover such modifications, or changes as may come within the scope of the following claims.

Claims

What is claimed is:

1. An improved electrostatic reproduction machine having a photoconductive surface upon which is formed an electrostatic latent image, a developing apparatus for applying developing material to said latent image to develop the same, said material including toner particles which are electrostatically attractable to said latent image, and a cleaning mechanism for removing residual toner particles from said surface after development of said latent image, the improvement comprising:

an air conveying system having an input and an output end, and blower means positioned between said ends for effecting movement of air throughout said system;

said input end being operatively connected to said cleaning mechanism for receiving air and toner particles there-from;

separating means positioned in said system between said input end and said blower means, said separating means having inlet and outlet means for the movement of air therethrough and discharge means for discharging separated toner particles from said system;

a toner recovery container having an opening for receiving said separated toner and means for engaging said discharge means in a sealing relationship for receiving said separated toner, said container being positioned in operative communication with said discharge means and arranged to receive said separated toner from said separating means;

a toner dispenser for said developing apparatus, said dispenser having a mating element formed to engage said container in a manner which will permit said separated toner to be poured from said container into said dispenser without spillage.

2. An improved electrostatic reproduction machine according to claim 1, and further including means for supporting said container beneath said separating means, and for moving said container into a first position where it engages said discharge means, and into a second position where said container is disengaged from said discharge means.

3. An improved electrostatic reproduction machine according to claim 2, wherein said supporting and moving means includes means for biasing said container into one of said positions, and cam means for overcoming said biasing means and moving said container into the other of said positions.