Blade cleaning apparatus for flexible belt

A blade cleaning station is provided for an electrostatographic reproducing apparatus comprising an endless, flexible belt having an imaging surface thereon supported for movement between two support members defining a substantially horizontal top run therebetween. The cleaning station comprises a rigid stationary cleaning platen under the top run of the belt between the support members and a cleaning blade mounted in opposed relationship thereto on the imaging surface of the belt in interference with the imaging surface on said belt such that its beam deflection provides the force required to clean the imaging surface and the toner cleaned from the imaging surface lubricates the nip between the cleaning blade and the imaging surface.

CROSS REFERENCE TO RELATED APPLICATION 
Reference is made to copending application Ser. No. 773,288, entitled Blade 
Cleaning Apparatus for Removing Residual Toner from a Charge Retentive 
Surface, filed Sept. 6, 1985 in the name of Morton Silverberg. 
BACKGROUND OF THE INVENTION 
The present invention relates to an electrostatographic reproducing 
apparatus and more particularly to blade cleaning apparatus for use in 
cleaning an imaging surface of a endless, flexible electrostatographic 
imaging belt. 
In an electrostatographic reproducing apparatus commonly in use today, a 
photoconductive insulating member is typically charged to uniform 
potential thereafter exposed to a light image of an original document to 
be reproduced. The exposure discharges the photoconductive insulating 
surface in exposed or background areas and creates an electrostatic latent 
image on the member which corresponds to the image areas contained within 
the usual document. Subsequently, the electrostatic latent image on the 
photoconductive insulating surface is made visible by developing the image 
with developing powder referred to in the art as toner. Most development 
systems employ a developer material which comprises both charged carrier 
particles and charged toner particles which triboelectrically adhere to 
the carrier particles. During development the toner particles are 
attracted from the carrier particles by the charge pattern of the image 
areas in the photoconductive insulating area to form a powder image on the 
photoconductive area. This image may subsequently be transferred to a 
support surface such as copy paper to which it may be permanently affixed 
by heating or by the application of pressure. 
Many commercial applications of the above process employ the use of the 
photoconductive insulating member in the form of a belt which is supported 
about a predetermined path past the plurality of processing stations to 
ultimately form a reproduced image on copy paper. During the imaging 
procedure described above, and frequently during the step of transferring 
toner particles to the copy sheet all the toner is not transferred and 
some residual toner particles remain adhering to the photoconductive 
surface after the transfer. Various types of devices have been used in the 
prior art to clean the imaging surface of this residual toner particles. 
Such devices include, for example, webs and brushes, foam rollers, and 
rotating magnets enclosed in a stationary non-magnetic belt or 
alternatively, stationary magnets enclosed within a rotating non-magnetic 
shell. In addition, blades of either the wipe or chisel type have been 
used to remove residual toner from the imaging surface. Cleaning blades 
have proved particularly satisfactory for cleaning the imaging surfaces on 
structurally rigid imaging drums which have been conventionally used in a 
number of commercial applications. This is because the blade may be 
mounted rigidly against the drum at virtually any position thereof to 
provide the necessary cleaning force to clean the residual toner. However, 
in the use of flexible belts supported by a plurality of rolls or arcuate 
members around the processing path the flexibility of design is limited 
for the use of a cleaning blade to be in a position adjacent to one of the 
rolls or arcuate members about which the belt travels to provide adequate 
support for the belt cleaning action. Furthermore, with the cleaning blade 
positioned at positions corresponding to the three o'clock, six o'clock 
and nine o'clock positions around the feeder path of the imaging drum or a 
photoconductive belt, the residual toner tends to fall away thereby 
increasing the coefficient of friction between the blade and the imaging 
surface to such a level that the edge or tip of the blade tends to tuck 
under thereby causing subsequent cleaning failures. Accordingly, there is 
a desire to provide a cleaning system for use in a machine employing a 
belt type photoconductor wherein the necessary force between the blade and 
the belt is obtained as well as adequate lubrication of the blade tip by 
the cleaner toner 
PRIOR ART 
U.S. Pat. No. 3,706,108 (Taylor) describes an apparatus for cleaning a 
residual image from a photosensitive member wherein a rotatable hollow 
core cleaning brush rotates in contact with the belt surface to be 
cleaned, the belt being supported in frictional contact by means of a 
platen 24 (FIG. 1). Alternatively, the platen can be replaced by a roller. 
U.S. Pat. No. 4,527,887 (Vineski) describes a blade cleaner apparatus for a 
charge retentive surface which includes a lower seal 86 in contact with 
the photoreceptor web to insure that the cleaned or falling toner does not 
fall into the cleaning sump. 
SUMMARY OF THE INVENTION 
In a principal aspect of the present invention an electrostatographic 
reproducing apparatus comprising an endless, flexible belt having an 
imaging surface thereon supported for movement between two support members 
defining a substantially horizontal top run therebetween is provided with 
a blade cleaning station for removing residual toner particles from the 
imaging surface comprising a rigid stationary cleaning platen under the 
top run of the belt between the support members for supporting the belt 
thereon, and a blade mounted in opposed relationship to the cleaning 
platen on the imaging surface of said belt for removing residual toner 
therefrom, the cleaning blade being positioned in interference with the 
wiping surface on said belt supported by the cleaning platen such that its 
beam deflection provides the force required to clean the imaging surface 
and the toner cleaned therefrom lubricates the nip between the cleaning 
blade and the imaging surface. 
In a further aspect of the present invention, the cleaning blade is rigidly 
mounted within a cleaner sump housing on top of the run of the flexible 
belt which housing is provided with a flexible flap seal upstream of the 
cleaning blade in the process direction. 
In a further aspect of the present invention, the tip of the cleaning blade 
may be positioned directly opposite a portion of the cleaning platen or 
from 2 to 5 mm upstream of the cleaning platen in the process direction. 
In a further aspect of the present invention, the cleaning blade may be in 
wiping contact or chiselling contact with the imaging surface for removing 
toner therefrom.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
The invention will now be described with reference to the preferred 
embodiment of the cleaning apparatus in an electrostatographic reproducing 
apparatus employing same. 
Referring now to FIG. 1, there is shown by way of example, an automatic 
electrostatographic reproducing machine 10 which includes a removable 
processing cartridge employing the blade cleaning apparatus according to 
the present invention. The reproducing machine depicted in FIG. 1 
illustrates the various components utilized therein for producing copies 
from an original document. Although the apparatus of the present invention 
is particularly well adapted for use in automatically electrostatographic 
reproducing machines, it should become evident from the following 
description that it is equally well suited for use in a wide variety of 
processing systems including other electrostatographic systems and is not 
necessarily limited in application to the particular embodiment or 
embodiments shown herein. 
The reproducing machine 10 illustrated in FIG. 1 employs a removable 
processing cartridge 12 which may be inserted and withdrawn from the main 
machine frame in the direction of arrow 13. Cartridge 12 includes an image 
recording belt like member 14 the outer periphery of which is coated with 
a suitable photoconductive material 15. The belt is suitably mounted for 
revolution within the cartridge about driven transport roll 16, around 
belt tracking shoe 18 and travels in the direction indicated by the arrows 
on the inner run of the belts to bring the image bearing surface thereon 
past the plurality of xerographic processing stations. Suitable drive 
means such as motor 17 are provided to power and coordinate the motion the 
various cooperating machine components whereby a faithful reproduction of 
the original input scene information is recorded upon a sheet of final 
support material 30, such as paper or the like. 
Initially, the belt 14 moves the photoconductive surface 15 through a 
charging station 19 wherein the belt is uniformly charged with an 
electrostatic charge placed on the photoconductive surface by charge 
corotron 20 in known manner preparatory to imaging. Thereafter the belt 14 
is driven to exposure station 21 wherein the charged photoconductive 
surface 15 is exposed to the light image of the original input scene 
information, whereby the charge is selectively dissipated in the light 
exposed regions to record the original input scene in the form of 
electrostatic latent image. The exposure station 21 may comprise a bundle 
of image transmitting fiber lenses 22 produced under the tradename of 
"SELFOC" by Nippon Sheet Glass Company Limited, together with an 
illuminating lamp 24 and a reflector 26. After exposure of the belt 15 the 
electrostatic latent image recorded on the photoconductive surface 15 is 
transported to development station 27, wherein developer is applied to the 
photoconductive surface of the drum 15 rendering the latent image visible. 
Suitable development station could include a magnetic brush development 
system including developer roll 28, utilizing a magnetizable developer mix 
having course magnetic carrier granules and toner colorant particles. 
Sheets 30 of the final support material are supported in a stack 
arrangement on elevated stack support tray 32. With the stack at its 
elevated position, the sheet separator segmented feed roll 34, feeds 
individual sheets therefrom to the registration pinch roll pair 36. The 
sheet is then forwarded to the transfer station 37 in proper registration 
with image on the belt and the developed image on the photoconductive 
surface 15 is brought into contact with the sheet 30 of final support 
material within the transfer station 37 and the toner image is transferred 
from the photoconductive surface 15 to the contacting side of the final 
support sheet 30 by means of transfer corotron 38. Following transfer of 
the image, the final support material which may be paper, plastic, etc., 
as desired, is separated from the belt by the beam strength of the support 
material 30 as it passes around the arcuate face of the belt tracking shoe 
18, with the sheet containing the toner image thereon which is advanced to 
fixing station 39 wherein roll fuser 40 fixes the transferred powder image 
thereto. After fusing the toner image to the copy sheet, the sheet 30 is 
advanced to output rolls 42 to sheet stacking tray 44. 
Although preponderance of toner powder is transferred to the final support 
material 30, invariably some residual toner remains on the photoconductive 
surface 15 after the transfer of the toner powder image of the final 
support material. The residual toner particles remaining on the 
photoconductive surface after the transfer operation is removed from the 
belt 14 by the cleaning station 46 which comprises a cleaning blade 47 in 
scrapping contact with the outer periphery of the belt 14 and contained 
within cleaning housing 48 which has a cleaning seal associated with the 
upstream opening of the cleaning housing. Alternatively, the toner 
particles may be mechanically cleaned from the photoconductive surface by 
a cleaning brush as is well known in the art. 
Normally when the copier is operated in the conventional mode, the original 
document 52 to be reproduced is placed image side down upon a horizontal 
transport viewing platen 54 which transports the original past the 
exposure station 21. The speed of the moving platen and the speed of the 
photoconductive belt are synchronized to provide a faithful reproduction 
of the original document. 
It is believed that the foregoing general description is sufficient for the 
purposes of the present application to illustrate the general operation of 
an automatic xerographic copier 10 which can embody the apparatus in 
accordance with the present invention. 
The cleaning station will be described with additional reference to FIG. 2 
wherein the photoreceptor belt 14 having a photoconductive insulating 
surface 15 thereon is transported in the direction of the arrow through 
the cleaning station. The cleaning station 46 comprises a cleaning platen 
49 positioned under the top horizontal run of the imaging belt 14 with a 
cleaning housing 48 in opposed relationship on the top run of the 
photoconductive belt 14. Contained within the cleaner housing is a 
cleaning blade 47 rigidly held in blade holder 52 which is mounted to 
blade mount 54 which in turn is mounted to the cleaning housing 48. The 
cleaning blade 47 by virtue of its position and beam deflection is in 
opposed interference relationship with the top surface of belt 14 
supported by cleaning platen 49. Cleaning seal 50 is held by seal holder 
56 which is mounted to seal mount 58 upstream in the process direction of 
the cleaning blade. The seal in contact with the photoreceptor 14 insures 
that toner cleaned from the photoreceptor by the cleaning blade 47 does 
not escape in the upstream direction from the cleaning housing 48. As the 
photoreceptor 14 travels in the direction of the arrow, any residual toner 
remaining thereon is cleaned or scrapped from the imaging surface by the 
blade 47 and transported into the cleaning sump 60. Also illustrated in 
FIG. 2 are structural members 62 which may be used to optionally provide 
additional guidance of the photoreceptor belt during transport to the 
cleaning station. It should be noted that the cleaning blade, cleaning 
platen, cleaning seal together with the cleaning housing are at least as 
wide as the imaging area of the photoreceptor belt. In FIG. 2, the 
cleaning blade 47 is in a chiselling orientation with regard to the 
advancing photoreceptor belt. As the belt moves in the direction indicated 
by the arrow, the tip of the blade 47 chisels any residual toner from the 
surface of the belt and pushes it up into the cleaner sump 60. An 
alternative embodiment is that illustrated in FIG. 3 wherein the cleaning 
blade is in a wiping orientation with respect to the advancing 
photoreceptor belt. Also illustrated in FIG. 3 is a cleaning platen 49 
forming a larger area in opposed relationship to the cleaning blade. The 
alternative embodiment illustrated in FIG. 4 illustrates the tip of the 
cleaning blade being positioned from 2 to 5 mm upstream in the direction 
of the leading edge of the cleaning platen. 
In operation in either the chiselling or wiping mode the cleaning blade 
which is mounted in fixed opposed relationship to the cleaning platen on 
the opposite side of the imaging surface, uses pressure interference 
engagement with the photoconductive surface of the belt by means of its 
beam deflection to provide the force required to clean the imaging surface 
of toner. In addition, in view of the orientation of the cleaning blade at 
roughly the twelve o'clock position, toner material which has been 
loosened and cleaned from the imaging surface remains in the nip between 
the cleaning blade and the imaging surface and lubricates the surface of 
the nip so that the leading edge or tip of the cleaning blade does not 
tuck under the main body of the cleaning blade thereby causing cleaning 
failures. The cleaning blade may be made of any suitable materials such as 
metal or plastic but preferably is made from an elastomer such as 
urethane. The cleaning seal may be made from a suitable material such as 
polyurethane, cellulose acetate or Mylar. 
Thus, according to the present invention, a cleaning system for use with 
electrostatographic imaging apparatus employing a flexible belt containing 
a charge retentive surface having an imaging surface thereon is provided 
with a cleaning apparatus which permits enormous flexibility in 
architecture in that the blade does not have to be disposed adjacent to a 
roller, a drive roll or a backup roll. It provides a relatively simple 
design which could be fabricated in a most economical manner in that it 
omits the use of pivot springs and rotating backup roll. Furthermore it 
enable the blade to be positioned and accurately fixed at the time of 
initial assembly. This is because the blade may be rigidly mounted and 
clamped in place so that its deflection beam strength enables the blade to 
be in interference with the supported belt to obtain the normal cleaning 
force. In addition, the deflected blade acts as a spring and the deflected 
photoreceptor under the blade acts as a spring in conjunction with the 
belt tensioning system. The geometry also helps to open up the mechanical 
tolerance window of a rigid mounted cleaner system, provide optimum 
cleaner performance, insure belt flatness under the blade tip and allow 
for higher blade forces without causing the photoreceptor belt to stall. 
The rigid mounted blade cleaner and backup support also help to reduce 
cost by eliminating parts necessary to spring load and/or pivot earlier 
cleaning blade systems. 
The disclosures of the patents referred to herein are hereby specifically 
and totally incorporated herein by reference. 
While the invention has been described with reference to specific 
embodiments, it will be apparent to those skilled in the art that many 
alternatives, modifications and variations may be made. For example, while 
the invention has been illustrated with an electrostatic latent image 
formed by the exposure of an electrostatically charged photoconductive 
member to light image of an original document, the electrostatic latent 
image may alternatively be generated from information electronically 
stored or generated in digital form which may afterward be converted to 
alpha-numeric images by image generation and electronics and optics. 
Accordingly it is intended to embrace all such alternatives and 
modifications that may fall within the spirit and scope of the appended 
claims.