US3706108A

US3706108A - Apparatus for cleaning a residual image from a photosensitive member

Info

Publication number: US3706108A
Application number: US101893A
Authority: US
Inventors: Clarence Reynold Taylor
Original assignee: Eastman Kodak Co
Current assignee: Eastman Kodak Co
Priority date: 1970-12-28
Filing date: 1970-12-28
Publication date: 1972-12-19
Anticipated expiration: 1989-12-19
Also published as: GB1373410A; FR2120814A5; CA938659A; DE2163610A1

Abstract

Residual toner particles remaining after transfer of a developed image from a photoconductive surface are cleaned therefrom by a rotatable, hollow core cleaning brush whose blades sweep loose the toner particles from the photoconductor. The brush is provided with a plurality of openings located between the blades and in communication with the core through which the loosened toner particles are withdrawn by vacuum applied to the core. Removal of the residual toner particles may be further assisted by applying a bias voltage to the brush to attract the toner particles to the brush and by using a flicker bar to loosen the toner particles from the cleaning blades.

Description

[1 1 3,706,108 1 Dec. 19, 1972 United States Patent Taylor 1 [s41 APPARATUS FOR CLEANING A OTHER PUBLICATIONS 1Q), Krause, IBM Technical'Disclosure Bulleti Brush Cleaning Method .m c O R r .m y a Am M i 0m m R. v. FMm EE Y GV 6N. An N Ml "T l mm Lmca A U0 E .mT m mmm RP.m H U [73] Assignee: Eastman Kodak Company, Rochester, N.Y.

Primary Examiner-Leon G. Machlin 8 1970 Attamey -w. H. J. Kline and Douglas 1. Plague Appl. No.: 101,893

[22] ,Filed:

ABSTRACT Residual toner particles remaining after transfer of a [52] US. 15/308 developed image from a photoconductive surface are [51] Int. Cl. ....B08b 1/02 l an th r from y a rota le, h llow. c re l n- [58] Field of Search.15/308, 1,5, 309, 256,52, 2565; ing brush whose blades sweep loose the toner particles 117/19, 175; 1'13/637;29/121 R from the photoconductor. The brush is provided with aplurality of openings located between the blades and in communication with the core through which they [5 6] References Cited loosened toner particles are withdrawn by vacuum ap- UNITED STATES PATENTS plied to the core. Removal of the residual toner particles may be further assisted by applying a bias voltage 4/1969 Tanaka et to the brush to attract the toner particles to the brush 3,438,706 3,278,972 Hudson and by using a flicker bar to loosen the toner particles from the cleaning blades.

6 Claims, 3 Drawing Figures P'A'TENTEDuEc 19 me TRANSFER STATION CLARENCE R. TAYLOR INVENTOR.

ATTORNEYS APPARATUS FOR CLEANING A RESIDUAL IMAGE FROM APIIOTOSENSITIVE MEMBER BACKGROUND OF THE INVENTION charge on the photoconductive insulating surface-while the photoconductive. member iskept in darkness. The charged photoconductive member-is subsequently exposed to a radiation pattern to form a'latent electrostatic image. Exposure to radiation causes areas of the photoconductive insulating layer which are exposed to become conductive so that the charge in these exposed areas is dissipated. Areas not exposed to the radiation continue to act as insulators and thus retain their electrostatic charge. The electrostatic latent imagine is then toned by a suitable developer having toner particles which are attracted by the charged areas of the image to form a toner image. This toner image is then transferred to a suitable receiver by contacting the receiver to the image bearing photoconductive surface and applying a potential to the receiver'of opposite polarity to the charge on the toner particles to bring about image transfenI-Iowever, a small amount of residual toner I particles usually remains on the photoconductive surface which must be removed therefrom prior to the forming and transfer of subsequent imagesto prevent ghost images from being formed. during subsequent transfers.

There are many well known methods and apparatus .for cleaning photoconductive surfaces. One known method of cleaning a photoconductive surface utilizes a rotating brush mounted within a housing to which housing a vacuum is applied to withdraw the toner particles removed from the photoconductive surface away from the vicinity of the brush to clean it. One disadvantage of these prior art brush devices is that the rapid brushing of the photoconductive surface creates an airborne toner cloud, a portion of which may escape the housing to deposit on other parts of the apparatus. These deposits create cleaning problems and result in smudging and smearing of the copy if the parts of the apparatus on which the toner particles have deposited come into contact with the receiver.

SUMMARY OF THE INVENTION airborne toner cloud surrounding a cleaning brush.

Still another object of the invention is to provide cleaning apparatus adaptable to a great variety of 2v speeds and widths of photoconductive members and yet of simple design and construction, thoroughly efficient and reliablein operation, and economical to manufacture.

.located between the brush fibers which are in communication with the core. A vacuum applied to the core withdraws the toner particles removed from the photoconductor by the fibrous cleaning device through the openings between the brush fibers.

In a preferred embodiment of the invention, a cleaning brush whose blades are made of an electrically conductive material is rotated to sweep loose the toner particles from the photoconductive surface. An electrical potential is applied tothe brush by means of a flicker bar that contacts the brush blades as the brush rotates. By applying a potential to the brush which is opposite in polarity to the charge on the residual toner particles the electrostatic forces which hold the toner particles to the photoconductive surface can be overcome so that the particles are removed from the photoconductive surface. The flicker bar loosens the toner particles from the brush so that they are carried by the air flow through the openings between the brush blades and into the hollow core of the brush.

Other objects and advantages of the invention will become more apparent from the detailed description of the preferred embodiment which follows.

. BRIEF DESCRIPTION OF THE DRAWING FIG. 2 is an enlarged, section view taken along line A 2-2 of FIG. 1, showing the cleaning apparatus in greater detail. FIG. 3 is a section view, taken along line 3-3 of FIG. 2, showing further details of the cleaning apparatus.

DESCRIPTIONOF THE PREFERRED EMBODIMENT Referring now to the drawing there is shown an electrophotographic mechanism M, which includes an endless photoconductive belt 10, extending around spaced rollers 11 and 12. The belt 10 is illustrated as I being driven by motor 13 through a drive belt 14 con-, nected to the roller 12. The belt 10 is driven in the direction of arrow 15 past a charging station 16 which places a uniform electrical charge (either positive or negative) over its photoconductive surface; an exposure station 17 whereat the belt is exposed to a radiation pattern, such as a light image from an original, to discharge the photoconductive surface in accordance with the radiation pattern to form an electrostatic latent image; a developing station 18 whereat the latent image is developed by depositing toner thereon; a transfer station 19 whereat the developed image is transferred to a receiver; and finally a novel cleaning about the periphery of a cylinder 30 whose core,3,1 is' hollow. The brush-20 is mounted for rotation about

bearings

22 and 23 and is disposed so that a portion of 'the'brushblades 21 contacts the area of the photoconductive belt to be cleaned. Bearing 22 interconnects a housing or shroud 28 and a drive hub 25 connected to the brush cylinder 30 and bearing 23 interconnects the brush cylinder and a vacuum means described in detail below.,A platen 24 on the side of the photoconductive belt 10 opposite that of the brush :0 is provided to sup- I port the belt in frictional contactwith the brush. Alternatively, platen 24 can be replaced by a roller. The housing or shroud 28 extends around a portion. of the brush 20 and, as best seen in FIG. 3, has a masked down portion 29 to provide a close fit with the brush blades 21. t

Advantageously, the brush 20 is rotated. by means (not shown) attached to the drive hub so that it moves,as shown by arrow 26, in a direction opposite to the movement of the photoconductive belt 10 at the point of contact therewith. Rotation of the brush 20 causes theblades 21 to knock or sweep loose the'toner particles from the photoconductive surface of the belt 10. Means, such as a vacuum tube 33 inserted into the hollow core 31 of the brush cylinder has a source of vacuum (not shown) applied thereto to draw the loosened toner particles from the blades into the core for removal, through a series of openings or passageways .27 in the brush cylinder 30 located betweenthe brush blades and through slotsor ports of the vacuum tube 33 which are in communication with the passageways 27. v v

The toner particles which stick to the cleaning blades 21 are carried into the area enclosed by the shroud 28 where they are loosened from the cleaning blades 21 by a flexible metal flicker bar 32 mounted in the shroud 28 so that it contacts the cleaning blades as the brush rotates. The toner particles removed from the cleaning bladesby the flicker bar 32 are subsequently drawn off by the vacuum tube '33 through slots or ports 34 located in the vacuum tube 33 or through the passageways 27 of the brush cylinder 30 and the ports 35 of the vacuum tube 33.

Conveniently, the cleaning blades 21 are made from an electrically conductive rubber so that an electrical potential from source 36, opposite in polarity to the charge on the residual toner particles, can be applied to the brush 20, which is electrically isolated from its mounting, by means of the flicker bar 32.

Application of a bias voltage to the brush 20 of opposite polarity to the charge on the residual toner particles attracts the residual toner particles to the brush by overcoming the electrostatic forces which hold the Y 4 toner particlesto the photoconductive surface of the belt 10.

From the foregoing, the advantages of the present invention are readily apparent. The harmful effects 5 caused by escaping airborne 'toner particles are reduced by providing a cleaning brush having'a hollow core to which a vacuum is'applied so that the toner particles are drawn through the brush for removal. The apparatus is composed of structures which are small in size yet. economical to manufacture and with long life characteristics.

, The invention has been described in detail with reference to a preferred embodimentthereof, but it will be understood'that variations and modifications can be effected within the, spirit and scope of the invention.

lclaimz I w 1. Cleaning apparatus for cleaning residual toner particles from an irnagebearing support surface, said cleaning apparatus comprising: 1"

a. a hollow core cleaning element having at least one blade extending outwardly from the exterior surface of said core and at least one passageway communicating between the exterior and interior sur- 25 I I faces of said core;

' Y b. means for mounting said cleaning element so that said blade engages theportio'n of said image bearing surface to be cleaned; c. a shroud substantially surrounding at least a por- 30 tion of said cleaning element;

d. flicking means mounted in said shroud in interferen'ce relation to said blade;

e. means for moving said cleaning element and said image bearing surface relative to each other to remove toner particles from said image bearing surface and for moving said cleaning element relative to said flicking means to remove toner particles from said cleaning element; and

f. means'for applying'a vacuum to. said core to withdraw the toner particles removedfrom said cleaning element by' said flicking means into said core through said passageway. v

2. Cleaning apparatus for cleaning residual toner particles from an image-bearing surface, said cleaning apparatus comprising! a. arotatable, hollow core cleaning brush having a plurality of. blades spaced at substantially equal intervals about its periphery and a plurality of passageways communicating with said core and said periphery of said cleaning brush; b. means for mounting said. brush for engagement with said image-bearing surface; c. means for rapidly rotating said brush;

d. means to cause relative motion between the axis of said brush and said image-bearing surface;

e. a shroud substantially surrounding at least a portion of said brush;

f. flicking means mounted in said shroud in interference relation to the brush blades to remove toner particles from said brush; and g. means for applying a'vacuum to said core to withdraw an airstream containing therein suspended toner particles removed from said image-bearing surface through said passageways. 3. Cleaning apparatus as claimed in claim 2 wherein the toner partiGles are charged to a first polarity and said blades of said brush are made of an electrically conductive material, said-cleaning apparatus further including: I

potential applying means connected to said flicking means. for applying an electrical potential of a second opposite polarity to said brush blades to attract said toner particles to said brush from said image-bearing surface.

4. Cleaning apparatus as claimed in claim 2 wherein said vacuum means includes a vacuum tube inserted into said core of said brush, said vacuum tube having a plurality of openings aligned with said passageways.

5. Apparatus as claimed in claim 4 wherein said means for mounting said brush includes first and second bearings, said first bearingbeingintercon-,'

space between two adjacent blades and communicating between said core and said periphery of said cylinder;

b. means for mounting said. brush for engagement with said photoconductive surface;

c. means for rapidly rotating said brush;

d. means to cause relative motion between the axis of said brush and said photoconductive surface;

e. a shroud substantially surrounding at least a portion of said brush;

f. an electrically conductive flicking means mounted in said shroud in interference relation to the brush blades to remove toner particles from said brush;

g. a source of electrical potential connected to said flicking means for applying to the brush blades an electrical potential of a second and opposite polarity to that of the residual toner particles so that said toner particles are attracted to said brush; and

h. means for applying a vacuum to said core to withdraw the toner particles removed from saidphotoconductive surface by said brush and from said brush by said flicking meansthrough said passageways, said means including a vacuum tube inserted into said core, said vacuum tube having a plurality of openings aligned with said passageways.

Claims

1. Cleaning apparatus for cleaning residual toner particles from an image-bearing support surface, said cleaning apparatus comprising: a. a hollow core cleaning element having at least one blade extending oUtwardly from the exterior surface of said core and at least one passageway communicating between the exterior and interior surfaces of said core; b. means for mounting said cleaning element so that said blade engages the portion of said image bearing surface to be cleaned; c. a shroud substantially surrounding at least a portion of said cleaning element; d. flicking means mounted in said shroud in interference relation to said blade; e. means for moving said cleaning element and said image bearing surface relative to each other to remove toner particles from said image bearing surface and for moving said cleaning element relative to said flicking means to remove toner particles from said cleaning element; and f. means for applying a vacuum to said core to withdraw the toner particles removed from said cleaning element by said flicking means into said core through said passageway.

2. Cleaning apparatus for cleaning residual toner particles from an image-bearing surface, said cleaning apparatus comprising: a. a rotatable, hollow core cleaning brush having a plurality of blades spaced at substantially equal intervals about its periphery and a plurality of passageways communicating with said core and said periphery of said cleaning brush; b. means for mounting said brush for engagement with said image-bearing surface; c. means for rapidly rotating said brush; d. means to cause relative motion between the axis of said brush and said image-bearing surface; e. a shroud substantially surrounding at least a portion of said brush; f. flicking means mounted in said shroud in interference relation to the brush blades to remove toner particles from said brush; and g. means for applying a vacuum to said core to withdraw an airstream containing therein suspended toner particles removed from said image-bearing surface through said passageways.

3. Cleaning apparatus as claimed in claim 2 wherein the toner particles are charged to a first polarity and said blades of said brush are made of an electrically conductive material, said cleaning apparatus further including: potential applying means connected to said flicking means for applying an electrical potential of a second opposite polarity to said brush blades to attract said toner particles to said brush from said image-bearing surface.

5. Apparatus as claimed in claim 4 wherein said means for mounting said brush includes first and second bearings, said first bearing being interconnected to said brush and said shroud, said second bearing being interconnected to said brush and said vacuum tube.

6. Cleaning apparatus for cleaning residual toner particles having a charge of a first polarity thereon from a photoconductive surface, said cleaning apparatus comprising: a. a rotatable cleaning brush, said brush comprising a cylinder having a hollow core, a plurality of electrically conductive blades mounted at substantially equally spaced intervals about the periphery of said cylinder, and a plurality of passageways each passageway being disposed in said cylinder in the space between two adjacent blades and communicating between said core and said periphery of said cylinder; b. means for mounting said brush for engagement with said photoconductive surface; c. means for rapidly rotating said brush; d. means to cause relative motion between the axis of said brush and said photoconductive surface; e. a shroud substantially surrounding at least a portion of said brush; f. an electrically conductive flicking means mounted in said shroud in interference relation to the brush blades to remove toner particles from said brush; g. a source of electrical potential connected to said flicking means for applying to the brush blades an electriCal potential of a second and opposite polarity to that of the residual toner particles so that said toner particles are attracted to said brush; and h. means for applying a vacuum to said core to withdraw the toner particles removed from said photoconductive surface by said brush and from said brush by said flicking means through said passageways, said means including a vacuum tube inserted into said core, said vacuum tube having a plurality of openings aligned with said passageways.