US3677224A

US3677224A - Toner charging and feeding machine

Info

Publication number: US3677224A
Application number: US73397A
Authority: US
Inventors: Alonzo W Noon
Original assignee: Electroprint Inc
Current assignee: Kotobuki Seiyaku Co Ltd; Electroprint Inc
Priority date: 1970-09-18
Filing date: 1970-09-18
Publication date: 1972-07-18
Anticipated expiration: 1989-07-18

Abstract

A toner charging and feeding machine using a generally flat carrier having a rough outer surface and means for driving the carrier along a predetermined path, toner supply means positioned across the carrier for depositing toner thereon, scraper means positioned across the carrier surface for scraping off excess toner deposited above the protuberances of the rough outer surface of the carrier, a toner cloud chamber positioned over the carrier, and means for directing a stream of air against the outer surface of the carrier and into the toner cloud chamber for entraining toner particles in the air stream, charging the particles, and developing a toner cloud.

Description

United States Patent Nwn [451 July 18, 1972 54] TONER CHARGING AND FEEDING 3,445,270 5/1969 Lorck 18/63 MACHINE 451,376 6/1969 Kazuo Obuchietul ..118/63 [72] Inventor: Alonzo W. Noon, Los Altos, Calif,

[73] Assignee: Electroprint, Inc., Palo Alto, Calif.

[22] Filed: Sept. 18, 1970 [21] Appl. No.: 73,397

[52] US. Cl ..118/63,'117/17.5,118/50, 118/308, 118/637 [51] Int. Cl. ..B05c 11/00 [58] Field of Search ..118/50, 63, 308, 309, 637;

[56] References Cited UNITED STATES PATENTS 3,273,496 9/1966 Melmon ..118/637 2,173,032 9/1939 Wintermute ..118/63 OTHER PUBLICATIONS R. C. Burns, Developing Magnetic Images from a Fluidized Magnetic lnk Bed, lBM Digest, Vol. 4, No. 3, August, 1967.

Primary Examiner-Mervin Stein Assistant Examiner-Leo Millstein Attorney-Townsend and Townsend [5 7] ABSTRACT A toner charging and feeding machine using a generally flat carrier having a rough outer surface and means for driving the carrier along a predetermined path, toner supply means positioned across the carrier for depositing toner thereon, scraper means positioned across the carrier surface for scraping off excess toner deposited above the protuberances of the rough outer surface of the carrier, a toner cloud chamber positioned over the carrier, and means for directing a stream of air against the outer surface of the carrier and into the toner cloud chamber for entraining toner particles in the air stream, charging the particles, and developing a toner cloud.

l7 Claim, 18 Drawing figures Patentedv July 18, 1972 3,677,224

4 Sheets-Sheet l INVENTOR. ALONZO W. NOON F IG 2 BY ATTORNEYS 4 Sheets-Sheet. 2

FIG 4 INVENTOR. ALONZO W. NOON ATTORNEYS Patented July 18, 1972 4 Sheets-Sheet 3 w R 0 MN E VW NO 2 w L A ATTORNEYS Patented July 18, 1972 4 Sheets-Sheet 4 "f :==I-"" -m INVENTOR. ALONZO W. NOON BY WAT ATTORNEYS TONER CHARGING AND FEEDING MACHINE This invention relates to a new and improved system for charging and feeding toner particles to form a charged toner cloud for use in electrostatic printing and similar applications.

It is an object of the present invention to provide a new and improved toner charging and feeding machine for producing a cloud of evenly dispersed charged toner particles with little flocculation between the particles.

A further object of the invention is to provide an apparatus for developing a charged toner cloud with little disperson of toner particles in adjacent equipment.

In order to accomplish these results, the present invention generally contemplates providing a generally flat carrier and means for driving the carrier along a predetermined path, means for supplying and distributing a uniform layer of toner along the carrier, and means for directing a stream of air against the carrier for entraining toner in the air stream to form a toner cloud and for charging the toner particles in the turbulence created by the air stream impinging on the carrier surface. A chamber is positioned over the carrier and formed with an inlet opening in the path of the air stream deflected from the carrier thereby to collect the formed toner cloud.

According to one aspect of the invention, the carrier is formed with a rough outer surface and is driven along a predetermined path. A toner supply cavity is positioned across the carrier with an opening over the rough outer surface of the carrier for depositing toner on the rough outer surface as it passes beneath the cavity. The invention also contemplates providing a wiper or scraper blade across the surface of the carrier on the downstream side of the toner supply cavity for scraping off excess toner above the protuberances of the rough outer surface of the carrier. A feature and advantage of this arrangement is that a substantially uniform density of toner is provided along the length of the carrier as it passes the scraper, and toner is thereby delivered at a substantially uniform rate.

According to another aspect of the invention, a toner cloud collector and diffuser chamber is positioned over the carrier path downstream from the toner supply cavity and scraper. The chamber is formed with sidewalls extending away from the carrier and an inlet opening adjacent the carrier formed by a lip spaced above the carrier. Nozzle means is provided for delivering a stream of air against the outer surface of the carrier and in the direction of the inlet opening at the bottom of the toner cloud chamber. A feature and advantage of this arrangement is that the toner particles are thereby entrained in the air stream to form a toner cloud and the turbulence produced by impingement of the air stream on the carrier surface results in charging the particles. The charged toner cloud is collected and channeled by the toner cloud collector and diffuser chamber for delivery to, for example, an electrostatic printing site. Alternately, the toner cloud chamber can be in the form of a housing or chamber directly over the carrier and the air stream orjet source.

In one form of the invention, the air stream is provided in the form of a plurality of jets of air delivered by a manifold positioned across the carrier and a row of nozzles extending from the manifold in the direction of the carrier and the toner cloud chamber. A motor and eccentric linkage are provided for reciprocating the manifold and nozzles across the carrier so that all portions of the rough outer surface are subjected to the air jets. A carrier surface cleaner can also be provided in the path downstream from the toner delivery site for removing any toner particles remaining on the carrier. The carrier cleaning apparatus consists of a similar arrangement of manifold and nozzles, but, in the case of the cleaner, housed within a vacuum chamber for removing dislodged toner particles.

In another embodiment of the invention, the carrier comprises a continuous belt loop having a rough outer surface and is driven around a predetermined path by a drum arrangement. The toner supply cavity having an opening adjacent the outer surface of the belt for depositing toner is positioned across either a horizontal or a non-horizontal portion of the belt path and in the latter case with the cavity opening positioned at an angle from the horizontal. In this latter arrangement, a wiper or scraper means is positioned across the belt along both the upstream and downstream sides of the cavity for scraping off excess toner deposited above the protuberances of the rough outer surfaces of the belt at one side of the cavity, and for preventing toner from escaping from the cavity at the other side. Alternately, the elements of the invention can be constructed and arranged around a single drum having a rough outer surface, or in conjunction with a variety of other carrier configurations.

A feature and advantage of the present invention is that the elements can be arranged so that substantially all of the toner particles uniformly deposited along the outer surface of the belt are delivered by the air jet stream to the toner cloud chamber. Thus, the rate of deposition of toner on the belt and the rate of delivery of toner to the cloud chamber can be equalized to eliminate the necessity of cleaning the belt.

In applications for electrostatic printing it may be advantageous to impart a horizontal or lateral component of motion to the developed toner cloud and the invention also contemplates a variety of techniques for effecting this result.

Other objects, features and advantages of the present invention will become apparent in the following specification and accompanying drawings. In the drawings:

FIG. I is a diagrammatic side view of a toner charging and feeding machine according to the present invention.

FIG. 2 is a diagrammatic plan view of the toner charging and feeding machine.

FIG. 3 is a detailed fragmentary diagrammatic side crosssectional view of the portion of the machine including the toner supply cavity, scraper, manifold and nozzle assembly, and toner cloud chamber.

FIG. 4 is a detailed fragmentary diagrammatic and crosssectional view through the toner cloud chamber.

FIG. 5 is a detailed diagrammatic side cross-sectional view of the cleaning apparatus.

FIG. 6 is a detailed fragmentary and cross-sectional view of the cleaning apparatus.

FIG. 7 is a detailed fragmentary side cross-sectional view of another form of toner supply cavity.

FIG. 8 is a diagrammatic side view of another toner charging and feeding machine arranged around the surface of a drum.

FIG. 9 is a diagrammatic side view of another toner charging and feeding machine assembled around a continuous belt.

FIGS. 10 and 11 are detailed fragmentary views of a portion of the system illustrated in FIG. 9 with and without a baffle element, respectively.

FIG. 12 is a fragmentary diagrammatic detailed view of the rough outer surface of a carrier.

FIG. I3 is a perspective view of a nozzle and jet spoiler.

FIGS. 14 through 18 are diagrammatic side views of the operational steps of the toner charging and feeding method using a shutter mechanism.

In the toner charging and feeding machine illustrated in FIGS. 1 and 2 there is provided a continuous or endless belt 11 having a rough, sandpaper-like outer surface. The belt travels around an idler drum I2 and a drive drum l3 driven by a controllable speed motor (not shown). A flat plate 14 provides a support for the belt between the drums l2 and 13 and the entire assembly is mounted on base 31. Dry toner is contained in a shaped toner supply cavity 15. Referring also to FIG. 3, toner supply cavity 15 is open at the bottom adjacent the surface of the belt for depositing toner on the belt as it passes beneath the cavity. With the belt travel direction as indicated in FIG. 1, the downstream side of the cavity, i.e., the side of the cavity facing in the direction of the belt travel, consists of a fixed plate 16 spaced above the belt to which is fixed a flexible wiper blade or scraper 17 arranged across the belt to contact the rough belt surface at an angle.

Following the wiper blade 17 on the downstream side of the belt travel path is supported a manifold 18 consisting of a tube positioned across the belt provided with a supply line 18a connectible to a source of air under pressure. Connected to the manifold tube 18 are a plurality of nozzles 19 arranged in a parallel row and directed downward at an angle so that the exit ends of the nozzles are close to the surface of belt 11.

The closed end of the manifold tube 18 is connected to a crank eccentric 19a by a connecting rod 20. The tube 18 itself is supported by bearing

blocks

22 and 23. The crank 19 is connectedto the shaft of a controllable speed motor 21.

Guide members

24 and 24a maintain the nozzles 19 at a desired angle relative to the belt 11. The manifold arrangement and linkage is further shown in FIG. 4.

Next downstream from the manifold and nozzle assembly in the belt travel path is a toner cloud collector and diffuser assembly or chamber 25 mounted on the plate 14 as shown in the FlGS. 1 through 4. On the side ofthe toner cloud collector and diffuser chamber 25 adjacent the nozzles 19 is provided an inlet opening consisting ofa lip 26 spaced above the belt 11 in the path of the air streams delivered by nozzles 19. The inlet opening lip 26 also forms a short duct opening into the chamber formed by

walls

27 and 28 extending away from the belt 11. The flared or funnel shaped chamber enables the delivering of a formed toner cloud to an appropriate site for electrostatic printing or other use. The side of chamber 25 away from the manifold 18 and nozzle 19 terminates in a flat horizontally disposed plate 29 spaced closely adjacent the belt 11.

A belt cleaning device 30 is mounted on base 31 and includes a chamber or housing 34 having an opening adjacent the belt surface along a portion of the belt passing around drum 13 as illustrated in FIGS. and 6. Also enclosed within the housing 34 is a manifold and nozzle array assembly 32 similar to that heretofore described. The nozzles are directed at an angle against the surface of the belt and in a direction opposite the belt travel direction to remove any remaining toner particles adhering to the surface of the drum. The manifold 32 is connected by rod 33 to a crank (not shown). The crank is, in turn, connected to a motor which drives the manifold and nozzle array 32 in a reciprocating motion across the face of the surface of the belt. The manifold and nozzle array 32 is supported by bushings mounted in the sidewalls of the housing 34. An opening at the end of housing 34 is connected by tube 35 to a suction and filtering apparatus (not shown). The manifold and nozzle array 32 is connected to a compressed air supply source not shown.

in operating the toner charging and feeding machine, dry toner is placed in the toner supply cavity and the motor driving drum 13 is started. Belt speeds in the range of from onehalf inch per second to over 12 inches per second have been used successfully. Toner from the supply cavity fills the spaces between and around all the protuberances on the rough belt surface and as the belt advances under the wiper blade 17, excess toner above the peaks of the protuberances is blocked and retained within the cavity 15 providing a uniform layer as shown in FIG. 12. The toner loaded belt thereafter passes beneath the nozzles 19 and air stream or jets issuing from the nozzles agitate the toner and entrain it along with the moving air. The toner laden air stream thereafter passes into the collector diffuser chamber through the inlet beneath lip 26 and is diverted away from the belt. The manifold 18 and nozzles 19 are reciprocated by motor 21 as heretofore described so that the air streams issuing from the nozzles sweep the entire belt surface removing most of the toner.

In one example, nozzles of approximately 0.008 inch in diameter and air pressures approximately 1.5 pounds per square inch were used successfully. The range of the reciprocating speed of the manifold 18 and nozzles 19 depends upon the belt speed, but in the aforementioned examples the range is typically about 1,200 to 1,500 cycles per minute. The concentration or density of the toner cloud produced can be controlled by varying the belt speed and/or the coarseness of the belt. In the examples, 80 to 120 grit sander belts were used successfully. The exit velocity of the toner cloud can be controlled by varying the air pressure applied to the manifold and nozzle array. ln addition, the exit velocity can be controlled by controlling the quantity of air entrained jets as hereinafter described.

The extreme turbulence created by the air streams impinging on the belt surface causes the toner particles to become charged, so that a flow of charged toner particles uniformly dispersed in air collects within and issues from the collector diffuser chamber 25.

Any toner remaining on the belt after it passes through the collector diffuser chamber 25 is removed by the cleaning device 30 and can be recirculated or recovered. As heretofore described, the cleaning device includes a housing with an opening adjacent a portion of the surface of the belt and a reciprocating nozzle array to remove the toner. Toner released from the surface ofthe belt is then removed from the housing by a suction and filtering system.

Another embodiment of the present invention in which the belt travels in the opposite direction from that heretofore described is illustrated partially in FIG. 7. The remaining portion of the system not shown is similar to that heretofore described with reference to FIGS. 1 and 2 except that the belt travel is in the opposite direction and the toner supply cavity is positioned on the other side of the collector chamber 25 along a non-horizontal portion of the belt path as illustrated in FIG. 7. According to this embodiment, the toner supply cavity is formed by the housing 37 having an opening positioned over and adjacent the belt 11 along a nonhorizontal position of the belt path on drum 13. The cavity is formed with a wiper blade 38 at the downstream side of the cavity in the direction of travel of the belt for wiping off excess toner deposited above the protuberances of the rough outer surface of the belt so that the excess toner is retained within the cavity. A second wiper blade is also provided along the upstream side of the cavity 37 also formed of a flexible material retained at an angle against the surface of the belt to prevent the toner 40 from escaping at the downhill side of the cavity 37. This construction and arrangement has the important advantage that it avoids the tendency for toner to accumulate and wedge under the wiper blade 38 across the downstream side of the cavity. In the arrangement of FIG. 7, the weight of the toner causes excess toner to fall back away from the wiper blade 38.

In the toner charging and feeding machine illustrated in FIG. 8, the entire assembly is arranged around the surface of a single drum 50 or carrier having a rough outer surface 51. A toner supply cavity 52 of the type set forth in and described with reference to FIG. 7 is provided at the periphery of the drum with an opening positioned over and adjacent the surface 51 along a non-horizontal portion of the drum surface. The supply cavity is formed with a wiper blade 53 at the downstream side of the cavity in the direction of travel of the surface of the drum for wiping off excess toner deposited above the protuberances of the rough outer surface of the drum so that excess toner is retained within the cavity 52. A second wiper blade 54 is provided along the upstream side of the cavity 32 formed of a flexible material and biased at an angle against the surface of the belt to prevent toner from escaping at the downhill side of cavity 52. Following the wiper blade 53 on the downstream side of the drum surface is supported a manifold 56 consisting ofa tube positioned across the belt provided with a plurality of nozzles 57 arranged in a parallel row and directed downward at an angle toward the surface of the drum and the nozzle array can be reciprocated in the manner heretofore described. The uniform layer of toner deposited on the rough outer surface of drum 50 is entrained in the jets of air emitted from nozzles 57 to form a charged cloud of toner particles in the space 58 above the surface of the drum.

In the arrangement of FIG. 8, the toner cloud is to be used for electrostatic printing using a modulated aperture electrostatic printing screen of the type set forth in, for example, U.S. Pat. application, Ser. No. 673,499, U.S. Pat. application, Ser. No. 776,146, and U.S. Pat. application, Ser. No. 85,070, filed on Oct. 29, I970, entitled Electrostatic Modulator for Controlling Flow of Charged Particles." Such a screen is positioned between the charged toner cloud and a back electrode 61 which supports a print-receiving medium. A potential is applied to back electrode 61 in order to accelerate charged toner particles through the screen 60 to a print-receiving medium supported against electrode 61. Because of a bipolar electrostatic latent image supported on screen 60, the toner particle flow is modulated in a configuration or pattern of an image to be reproduced so that the toner comes to rest upon the print-receiving medium in the desired pattern as fully described in the above-referenced patent applications. In the embodiment of FIG. 8, screen 60, back electrode 61, and the supported print-receiving medium are mounted for translation across an opening from the space 58 in which the charged toner is developed and as the screen and back plate assembly translate across the opening, toner is deposited on the printreceiving medium in the desired pattern.

It has been found that such an arrangement in which the electrostatic modulated-aperture screen 60, back plate 61, and print-receiving medium assembly is translated with reference to the toner charging and feeding machine, that it is advantageous to impart to the developed toner cloud a component of motion in the direction of motion of the screen having approximately the same velocity. By this expedient, toner particles passing through the screen onto the print-receiving medium deposit in dots of controlled size to provide high quality printing. In the event that there is relative motion in the lateral direction between the screen 60 and toner cloud, the toner tends to deposit in streaks on the print-receiving medium after passing through the holes or perforations of the screen. In order to effectuate this beneficial result, a low pressure manifold 63 is connected to the space 58 in which the.

toner cloud is developed and a low pressure source is applied to the channel 63 to impart a lateral component of motion to the toner cloud in the direction of the low pressure source. Ex-

cess toner not attracted through the screen by the back electrode 61 is also effectively removed by application of the low pressure source to channel 63. In order to prevent excess toner flow into the manifold channel 63 a baffle 59 is positioned at the channel opening downstream from the open area 62. The height of the baffle is not critical and can be adjusted to provide optimum performance for various operating conditrons.

Another arrangement for imparting a horizontal or lateral component of motion to the developed toner cloud for application in a continuous belt toner charger and feeder similar to that described with reference to FIGS. 1 and 2 is shown in FIG. 9. According to this embodiment, a belt 70 having a rough outer surface is supported for travel along the predetermined path by a pair of

drums

71 and 72. Along a nonhorizontal portion of the periphery of the drum 72 a toner supply cavity 73 of the type heretofore described with reference to both FIG. 7 and FIG. 8 is positioned. At the downstream side of the toner supply cavity 73 is provided a manifold 74 and nozzles 75 for entraining in the jets of air delivered from nozzles 75, toner particles deposited in a uniform layer along the rough outer surface of the belt 70 by toner supply cavity 73. In this example, the charged toner cloud develops in the region 76 over which an electrostatic screen modulator 77 and back plate 78 which supports a printreceiving medium are translated relative to the toner feeding machine. An outlet 80 communicating with the space 76 is connected to a low pressure source for imparting a horizontal or lateral component of motion to the developed toner cloud and for removing unused toner. A baffle 79 similar to that heretofore described can be positioned at the opening of channel 80 downstream from the printing area to prevent excessive toner flow into the channel 80.

A feature and advantage of the application of low pressure to the region of toner cloud development is that the higher pressure on the outside of the region of toner cloud development prevents leakage of toner into surrounding machinery.

Thus, because the air pressure is lower in the region 76, air leakage occurs inwardly.

Another technique for imparting a lateral or horizontal component of motion to the developed toner cloud is by orienting the diffuser chamber 25 in the embodiment of FIGS. 1 and 2 at an angle with respect to the belt travel path.

Positioned immediately above the high pressure air supply 74 and nozzles is a baffle 81 oriented at an angle with reference to the drum and nozzles for the purpose set forth in more detail with reference to FIGS. 10 and 11. As shown in FIG. 11, in which is illustrated a fragmentary portion of the system in FIG. 9, in the absence of baffle 81, back eddy currents or vortical flow develops in the air stream emerging from the nozzles 75. Although such turbulent vortical flow is advantageous in uniformly dispersing the toner cloud, it interferes in the development of a horizontal or lateral component of motion equal in velocity to the velocity of the translation of the screen 77 and back plate 78. With baffle 81 provided and oriented substantially as set forth in FIG. 10, a flow can be generated providing a uniform horizontal or lateral component of motion to the charged toner cloud entrained in the air stream.

The arrangement shape and configuration of components surrounding the space 76 generally can have a significant effect on the aerodynamics of the toner cloud generation and transport. The total air flow generated by the jets emerging from nozzles 75 is many times greater than the primary air emitted from the jets because of the great quantity of air surrounding the nozzles entrained in the air flow. The volume of entrained air can be controlled by various factors. For example, an air opening or inlet 85 behind the jet nozzles can provide a larger source of air for entrainment in the air jets if desired. On the other hand, in order to attenuate the entrainment of air a spoiler or blocking plate 86 can be provided around each nozzle 75 to block the air flow 87 generated by entrainment of surrounding air in the jet streams 88 emerging from nozzles 75 as shown in FIG. 13. The shape and size of the region 76 and regions surrounding the components can also be varied for controlling the air flow.

In order to provide more complete control of the toner particles within the toner feeding and printing apparatus a shutter arrangement is provided in the embodiment of the invention illustrated in FIGS. 14 through 18. The toner charging and feeding apparatus set forth in these figures is similar to the apparatus shown in FIG. 8 with corresponding components numbered accordingly, except that a shutter mechanism is interposed over the outlet from chamber 58 in which the toner cloud is developed. The shutter mechanism, 101 comprises a front shutter 103 and a rear shutter 102 which prevent passage of toner from the chamber 58 until the shutter opens. The electrostatic screen modulator 104 is mounted in a frame 105 which moves in conjunction with back electrode 61 over the shuttered opening from chamber 58. A print receiving medium can be retained against the back electrode 61 in alignment with the screen by means of an array of tiny vacuum holes through which low pressure can be communicated to the electrode surface for retaining the printing paper or other print receiving medium.

As the screen and back electrode pass over the shuttered opening from the space 58 upon the surface of drum 51 the front shutter 103 moves with the screen frame 105 allowing the toner cloud to pass through the space 58 toward the back electrode 61 by way of the modulating screen 104. By this expedient the forward portion of the screen frame 105 is shielded from the toner cloud so that it does not become contaminated with toner particles. The front shutter stops when it is fully open and the screen continues to move across the opening from space 58 for deposition of toner via the modulated screen for reproducing the entire image on the print receiving medium retained against the surface of the back electrode 61. This initial functioning is illustrated in FIGS. 14 and 15.

As the portion of the screen frame 105 reaches the opening over space 58 the rear shutter 102 moves with the frame shielding the frame until the opening over space 58 is entirely closed by rear shutter 102 as shown in H6. 16. Thereafter the screen 104 and back electrode 61 reverse direction moving away from the toner charging and feeding machine. At the same time both elements of the shutter mechanism move together to the original position of electrode 61 and the screen travels to the imaging station as illustrated in FIG. 18.

Application of the accelerating field between the charged toner cloud and back electrode can also be used to facilitate control of the toner. Thus, in one embodiment the application of voltage to the back electrode is switched on and off, in synchronism with the shutter operation. Thus upon initial movement of the front shutter 103 from the original position thereby opening the outlet from space 58 the voltage to the back electrode is switched on to accelerate the charged toner cloud through the screen. Similarly, upon completion of motion of the rear shutter 102 closing the outlet from space 58, voltage to the back electrode 61 can be switched off. By means of the shutter mechanism and the switching control, contamination of the interior components of the apparatus by toner particles can thereby be minimized.

It is apparent that the toner charging and feeding machine contemplated by the present invention can be embodied in a variety of configurations in which a generally flat carrier having a rough outer surface travels along a predetermined path for delivering a uniform layer of toner to be entrained in air jets and dispersed in a charged toner cloud.

What is claimed is:

1. A toner charging and feeding machine comprising:

a continuous carrier having a rough sandpaper-like outer surface comprising protuberances of selected grit size ac cording to the quantity of toner to be deposited on the carrier for generating a toner cloud ofdesired concentration and density and means for driving said carrier along a predetermined path;

toner supply means positioned relative to the carrier surface for depositing toner thereon;

flexible scraper means positioned relative to and biased against the carrier surface for scraping off excess toner deposited above the protuberances of the rough outer surface of the carrier so that interspaces between the protuberances are filled with toner marking material to a uniform level at the tops of the protuberances;

and means for directing a stream of air against the outer surface of the carrier for entraining toner thereby to form a charged toner cloud.

2. A toner charging and feeding machine as set forth in claim 1 wherein is also provided chamber means positioned relative to the surface of the carrier and the deflected air from the carrier surface thereby to collect the formed toner cloud.

3. A toner charging and feeding machine as set forth in claim 2 wherein said chamber means is provided with a first outlet for delivering toner to an application site and wherein is provided a second outlet and low pressure source means connected to said outlet for imparting a lateral component of motion to the formed toner cloud and for removing unused toner particles.

4. A toner charging and feeding machine as set forth in claim 1 wherein said carrier comprises a drum.

5. A toner charging and feeding machine as set forth in claim 1 wherein said carrier comprises a belt supported and driven by rollers.

4 6. A toner charging and feeding machine comprising:

a generally flat elongate belt having a rough outer surface comprising protuberances of selected grit size according to the quantity of toner to be deposited on the belt for generating a toner cloud of desired concentration and density and means for driving said belt along a predetermined path;

a toner supply cavity positioned across the belt having an opening adjacent the outer surface of the belt for depositing toner thereon;

flexible scraper means positioned across the belt on the downstream side of the cavity and biased against the surface of the belt for scraping off excess toner deposited above protuberances of the rough outer surface of the 5 belt so that the interspaces between protruberances of the rough outer surfaces are filled with toner to a uniform level at the tops of the protuberances;

a toner cloud collector chamber positioned over said belt downstream from the toner supply cavity;

and means for delivering jets of air against the outer surface of the belt and into the toner cloud chamber.

7. A toner charging and feeding machine as set forth in claim 6 wherein said means for delivering jets of air comprises a manifold positioned across the belt and a row of nozzles extending from the manifold in the direction ofthe belt and inlet opening of said toner cloud chamber.

8. A toner charging and feeding machine as set forth in claim 7 wherein is also provided means for reciprocating said manifold and nozzles across the belt.

9. A toner charging and feeding machine as set forth in claim 8 wherein is provided belt cleaning means comprising a housing having an opening positioned over the outer surface of said belt, and second means for delivering jets of air against the outer surface of the belt as it passes within the housing.

10. A toner charging and feeding machine as set forth in claim 9 wherein said second means for delivering jets of air comprises a manifold positioned across the belt and a row of nozzles extending from the manifold in the direction of the belt and inlet opening of said toner cloud chamber.

11. A toner charging and feeding machine as set forth in claim 10 wherein is also provided means for reciprocating said manifold and nozzles across the belt.

12. A toner charging and feeding machine comprising:

a drum having a rough outer surface comprising protuberances of selected grit size according to the quantity of toner to be deposited on the drum surface for generating a toner cloud of desired concentration and density, and means for rotating said drum;

a toner supply cavity positioned across the surface of the drum having an opening adjacent the outer surface of the drum for deposition of toner thereon;

flexible scraper means positioned across the drum surface on the downstream side of the cavity and biased against the surface for scraping off excess toner above protube rances of the rough outer surface of the drum so that the interspaces between the protuberances are filled with marking material to a uniform level at the tops of the protuberances;

means for delivering jets of air against the outer surface of the drum;

and toner cloud collector chamber means positioned over a portion of the drum surface and over the jets of air deflected from the surface of the drum.

13. A toner charging and feeding machine as set forth in claim 12 wherein said means for delivering jets of air comprises a manifold positioned across the drum surface and a row of nozzles extending from the manifold in the direction of the drum surface.

14. A toner charging and feeding machine comprising:

a continuous belt carrier having a rough sandpaper-like outer surface comprising protuberances having selected grit size according to the quantity of toner to be deposited on the carrier for generating a toner cloud of desired concentration and density, and roller means for driving said belt around a predetermined path including a nonhorizontal path portion;

a toner supply cavity positioned across the carrier surface having an opening adjacent the outer surface of the carrier for depositing toner thereof, said cavity arranged across a non-horizontal portion of the carrier path with the cavity opening positioned at an angle from the horizontal;

flexible wiper means positioned across the carrier surface on each side of the cavity for scraping off excess toner deposited above protuberances of the rough outer surface of the carrier at one side of the cavity and for preventing toner from escaping from the cavity at the other side;

means for delivering jets of air against the outer surface of the carrier;

and toner cloud collector chamber means positioned over a portion of the carrier surface and over the jets of air deflected from the surface of the carrier.

15. A toner charging and feeding machine comprising:

a continuous belt loop having a rough sandpaper-like outer surface comprising protuberances of selected grit size according to the quantity of toner to be deposited on the belt for generating a toner cloud of desired concentration and density and roller means positioned for driving said belt around a predetermined path substantially horizontal between the roller means and including non-horizontal portions around the roller means;

a toner supply cavity positioned across the belt having an opening adjacent the outer surface of the belt for depositing toner thereon, said cavity arranged across a nonhorizontal portion of the belt path with the cavity opening positioned at an angle from the horizontal;

flexible wiper means positioned across the belt and biased against the surface of the belt on each side of the cavity for scraping off excess toner deposited above the protuberances of the rough outer surface of the belt at one side of the cavity so that interspaces between the protuberances are filled with toner to a uniform level at the tops of the protuberances, and for preventing toner from escaping from the cavity at the other side;

a toner cloud collector chamber positioned over said belt downstream from the toner supply cavity, said toner cloud collector chamber provided with a first outlet for delivering toner to an application site and also provided with a second outlet;

means for delivering jets of air against the outer surface of the belt for entraining toner in the jets of air and deflecting the jets of air and entrained toner into the toner cloud collector chamber;

and means for applying low pressure to the second outlet of the toner cloud collector chamber positioned over the belt for imparting a lateral component of motion to the formed toner cloud and for removing unused toner particles.

16. A toner charging and feeding machine as set forth in claim 15 wherein is provided over the first outlet of the toner cloud collector chamber for delivering toner to an application site a shutter means for selectively blocking and passing a developed toner cloud.

17. A toner charging and feeding machine as set forth in claim 15 wherein is provided over the air jet delivering means, baffle means positioned in relationship to the air jet delivering means for controlling turbulence.

Claims

1. A toner charging and feeding machine comprising: a continuous carrier having a rough sandpaper-like outer surface comprising protuberances of selected grit size according to the quantity of toner to be deposited on the carrier for generating a toner cloud of desired concentration and density and means for driving said carrier along a predetermined path; toner supply means positioned relative to the carrier surface for depositing toner thereon; flexible scraper means positioned relative to and biased against the carrier surface for scraping off excess toner deposited above the protuberances of the rough outer surface of the carrier so that interspaces between the protuberances are filled with toner marking material to a uniform level at the tops of the protuberances; and means for directing a stream of air against the outer surface of the carrier for entraining toner thereby to form a charged toner cloud.

6. A toner charging and feeding machine comprising: a generally flat elongate belt having a rough outer surface comprising protuberances of selected grit size according to the quantity of toner to be deposited on the belt for generating a toner cloud of desired concentration and density and means for driving said belt along a predetermined path; a toner supply cavity positioned across the belt having an opening adjacent the outer surface of the belt for depositing toner thereon; flexible scraper means positioned across the belt on the downstream side of the cavity and biased against the surface of the belt for scraping off excess toner deposited above protuberances of the rough outer surface of the belt so that the interspaces between protruberances of the rough outer surfaces are filled with toner to a uniform level at the tops of the protuberances; a toner cloud collector chamber positioned over said belt downstream from the toner supply cavity; and means for delivering jets of air against the outer surface of the belt and into the toner cloud chamber.

7. A toner charging and feeding machine as set forth in claim 6 wherein said means for delivering jets of air comprises a manifold positioned across the belt and a row of nozzles extending from the manifold in the direction of the belt and inlet opening of said toner cloud chamber.

12. A toner charging and feeding machine comprising: a drum having a rough outer surface comprising protuberances of selected grit size according to the quantity of toner to be deposited on the drum surface for generating a toner cloud of desired concentration and density, and means for rotating said drum; a toner supply cavity positioned across the surface of the drum having an opening adjacent the outer surface of the drum for deposition of toner thereon; flexible scraper means positioned across the drum surface on the downstream side of the cavity and biased against the surface for scraping off excess toner above protuberances of the rough outer surface of the drum so that the interspaces between the protuberances are filled with marking material to a uniform level at the tops of the protuberances; means for delivering jets of air against the outer surface of the drum; and toner cloud collector chamber means positioned over a portion of the drum surface and over the jets of air deflected from the surface of the drum.

14. A toner charging and feeding machine comprising: a continuous belt carrier having a rough sandpaper-like outer surface comprising protuberances having selected grit size according to the quantity of toner to be deposited on the carrier for generating a toner cloud of desired concentration and density, and roller means for driving said belt around a predetermined path including a non-horizontal path portion; a toner supply cavity positioned across the carrier surface having an opening adjacent the outer surface of the carrier for depositing toner thereof, said cavity arranged across a non-horizontal portion of the carrier path with the cavity opening positioned at an angle from the horizontal; flexible wiper means positioned across the carrier surface on each side of the cavity for scraping off excess toner deposited above protuberances of the rough outer surface of the carrier at one side of the cavity and for preventing toner from escaping from the cavity at the other side; means for delivering jets of air against the outer surface of the carrier; and toner cloud collector chamber means positioned over a portion of the carrier surface and over the jets of air deflected from the surface of the carrier.

15. A toner charging and feeding machine comprising: a continuous belt loop having a rough sandpaper-like outer surface comprising protuberances of selected grit size according to the quantity of toner to be deposited on the belt for generating a toner cloud of desired concentration and density and roller means positioned for driving said belt around a predetermined path substantially horizontal between the roller means and including non-horizontal portions around the roller means; a toner supply cavity positioned across the belt having an opening adjacent the outer surface of the belt foR depositing toner thereon, said cavity arranged across a non-horizontal portion of the belt path with the cavity opening positioned at an angle from the horizontal; flexible wiper means positioned across the belt and biased against the surface of the belt on each side of the cavity for scraping off excess toner deposited above the protuberances of the rough outer surface of the belt at one side of the cavity so that interspaces between the protuberances are filled with toner to a uniform level at the tops of the protuberances, and for preventing toner from escaping from the cavity at the other side; a toner cloud collector chamber positioned over said belt downstream from the toner supply cavity, said toner cloud collector chamber provided with a first outlet for delivering toner to an application site and also provided with a second outlet; means for delivering jets of air against the outer surface of the belt for entraining toner in the jets of air and deflecting the jets of air and entrained toner into the toner cloud collector chamber; and means for applying low pressure to the second outlet of the toner cloud collector chamber positioned over the belt for imparting a lateral component of motion to the formed toner cloud and for removing unused toner particles.