Toner removal and surface abrading apparatus for a charge retentive surface

In association with a blade cleaning arrangement supported for chiseling removal of toner from a charge retentive surface, an auger is provided to move toner to the edge of the charge retentive surface and simultaneously simulate a foam roll cleaner, known to have good abrasive characteristics in the presence of toner. An auger member having a roughened or sharpened surface in contact with a charge retentive surface is arranged slightly upstream and adjacent to a blade cleaning arrangement for the removal of residual toner accumulating adjacent to a cleaning blade after release from a charge retentive surface such as a photoreceptor in a reproduction machine. The auger member may be comprised of a foam material providing an abrading surface roughness. Other augering members simulate the abrading qualities of the foam roll cleaner, such as for example, a sharpened auger edge which lightly scrapes the charge retentive surface, or an auger of a polymeric material, with a roughed surface.

This invention relates to reproduction apparatus and more particularly to 
cleaning apparatus for removing residual toner from a charge retentive 
surface, and abrading that surface to remove film not removed by standard 
cleaning arrangements. 
INCORPORATION BY REFERENCE 
The following are incorporated by reference for the purpose of background 
information: 4,648,705 to Tachibana et al.; US-A 4,593,997 to Fox et al.; 
US-A 4,427,289 to Oda; JP 61-77882 (A) To Saito; US-A 4,329,044 to 
Kitajima et al.; US-A 4,213,794 to Woodling et al.; US-A 4,054,381 to 
Bernhard; and US-A 4,442,789 to Pirwitz; and, Snelling, Xerox Disclosure 
Journal Volume 5, No. 6, Nov./Dec. 1980, pp. 637, 638. 
BACKGROUND OF THE INVENTION 
In electrophotographic applications such as xerography, a charge retentive 
surface is electrostatically charged, and exposed to a light pattern of an 
original image to be reproduced to selectively discharge the surface in 
accordance therewith. The resulting pattern of charged and discharged 
areas on that surface form an electrostatic charge pattern (an 
electrostatic latent image) conforming to the original image. The latent 
image is developed by contacting it with a finely divided 
electrostatically attractable powder referred to as "toner". Toner is held 
on the image areas by the electrostatic charge on the surface. Thus, a 
toner image is produced in conformity with a light image of the original 
being reproduced. The toner image may then be transferred to a substrate 
(e.g., paper), and the image affixed thereto to form a permanent record of 
the image to be reproduced. Subsequent to development, excess toner left 
on the charge retentive surface is cleaned from the surface. The process 
is well known, and useful for light lens copying from an original, and 
printing applications from electronically generated or stored originals, 
where a charged surface may be imagewise discharged in a variety of ways. 
Although a preponderance of the toner forming the image is transferred to 
the substrate during transfer, some toner invariably remains on the charge 
retentive surface, being held thereto by relatively high electrostatic 
and/or mechanical forces. It is essential for potimum operation that toner 
and debris remaining on the surface be cleaned thoroughly therefrom. In 
addition to such toner and debris, a film build up is noted of material 
not removed by standard cleaning techniques. 
Blade cleaning is a highly desirable method for removal of residual toner 
from a charge retentive surface. In such an arrangement, a cleaning blade 
is provided and supported adjacent the charge retentive surface with a 
blade edge chiseling toner from contact with the surface. Subsequent to 
removal from the surface, toner is transported away from the blade area by 
a toner transport arrangement. Blade cleaning arrangements are very 
effective, inexpensive relative to other cleaning devices, and very 
serviceable over the device lifetime. Variations in lubricants and 
materials allow the use of blade cleaning at relatively high speed. 
Compared to brush cleaners, cleaning blades are less expensive and do not 
create the tirboelectric problems associated with brush cleaners handling 
electrostatically attractable powders. 
Removal of accumulating toner from the blade area may be accomplished in a 
variety of ways, each dependent on the machine arrangement. While a 
cleaning arrangement for a cylinder or a vertical surface may allow toner 
to simply fall from the blade area to a toner transport device such as an 
auger, as shown for example in 4,648,705 to Tachibana et al., or US-A 
4,593,997 to Fox et al., positioning the cleaning arrangement on a 
horizontal upwardly facing surface, sometimes referred to as twelve 
o'clock cleaning, requires removal of toner from the surface. Typically, 
toner might be removed from the blade area either by a brush arrangement 
which transports the toner to an auger arrangement for transport to 
another area, such as shown for example in US-A 4,427,289 to Oda and JP 
61-77882 (A) to Saito or directly by an augering arrangement, such as 
shown for example in US-A 4,329,044 to Kitajima et al. Either arrangement 
serves to transport toner removed from the charge retentive area 
satisfactorily. Generally the auger edge in contact with the charge 
retentive surface is smooth to avoid damage to surfaces. Brush augering 
arrangements are known for removal of toner from fiber brush cleaners, as 
shown in US-A 4,213,794 to Woodling et al. and for carrying toner along 
toner transport paths as shown in US-A 4,054,381 to Bernhard and US-A 
4,442,789 to Pirwitz. 
Over periods of time, despite the cleaning action of the blade a buildup of 
residue or toner film on the charge retentive surface may be noted, 
manifesting itself as comets, spots, and other copy quality defects, on 
copies made in the device. This film may be removed from the surface with 
a slight abrading action. Of course, it will no doubt be appreciated that 
the abrasion must not be so rough as to damage the charge retentive 
surface, but must be adequate to remove the buildup of toner film. It has 
been noted that a foam roll may be constructed adequately in this regard. 
In operation, foam cleaning rolls have a tendency to collect toner in open 
pores in the foam. The toner seated in the pores abrades the charge 
retentive surface as it comes into contact therewith, effectively scraping 
the buildup of contaminants from the charge retentive surface. 
Snelling, Xerox Disclosure Journal, Volume 5, No. 6, November/ December 
1980, pp. 637, 638, shows an auger-shaped member which simultaneously 
cleans and carries toner from a charge retentive surface with a pumping 
action created by its rotation within a closed container. However, it does 
not appear to suggest use of advantageous blade cleaning methods which 
sealingly prevent toner from passing through the cleaning station, suggest 
that abrasion of the charge retentive surface is desirable, nor suggest 
that foam material used should be provided with toner collecting pores for 
abrasion of the charge retentive surface. Foam roll cleaning devices used 
alone suffer from difficulties in cleaning toner from the foam roll. 
Additionally, the high speed believed required by the device to create an 
air pumping action, and satisfactorily clean the surface of the charge 
retentive surface would be higher than desirable to avoid wear on the 
charge retentive surface. Bean, Xerox Disclosure Journal, Volume 1, No. 8, 
August 1976, page 67, demonstrates a foam rubber helical cleaning member, 
also deficient in these aspects. 
SUMMARY OF THE INVENTION 
In accordance with the invention there is provided an improved cleaning 
arrangement for removal of toner and debris from a charge retentive 
surface of photoreceptor surface, which simultaneously transports toner 
away from the area adjacent to a toner removal device and abrades the 
charge retentive surface for the removal of toner film. Mechanical 
abrasion of the film or buildup on the photoreceptor improves the overall 
performance of the machine. Additionally, the use of mechanical film 
removal techniques eliminates any need for abrasive additives to toner. 
In accordance with one aspect of the invention, in association with a blade 
cleaning arrangement supported for chiseling removal of toner from a 
charge retentive surface, an auger member is provided to move toner to the 
edge of the charge retentive surface and simultaneously simulate a foam 
roll cleaner, known to have good abrasive characteristics in the presence 
of toner. An auger member having a roughened or sharpened surface is 
arranged slightly upstream and adjacent to a blade cleaning arrangement 
for the removal of residual toner accumulating adjacent to a cleaning 
blade after release from a charge retentive surface such as a 
photoreceptor in a reproduction machine. The auger member may be comprised 
of a foam material having a large number of open pores to collect toner 
and provide an abrading surface roughness. The foam spiral auger member is 
provided with a flat surface portion in contact with the photoreceptor for 
abrading the charge retentive surface for the removal of toner film. The 
augering motion of the foam auger member serves to simultaneously move 
toner and abrade the charge retentive surface. Other augering arrangements 
are also within the scope of the invention which simulate the abrading 
qualities of the foam roll cleaner, such as for example, a sharpened auger 
edge which lightly scrapes the charge retentive surface, or an auger of a 
polymeric material, roughed to simulate the toner collecting pores of a 
foam roll member. 
The abrading action of the auger also aids in removal of paper fibers and 
other impurities from the photoreceptor. By properly designing the auger 
and selecting an appropriate speed of rotation, the probability of paper 
fibers slipping by the augur can be minimized. The rate of toner removal 
from the toner pile in front of the blade must be fast compared to the 
time for incoming debris to reach the blade cleaning edge. Keeping loose 
debris from reaching the cleaning edge will have a significant effect on 
cleaning reliability.

Referring now to the drawings, where the showings are for the purpose of 
describing a preferred embodiment of the invention and not for limiting 
same, the various processing stations employed in the reproduction machine 
illustrated in FIG. 1 will be described only briefly. It will no doubt be 
appreciated that the various processing elements also find advantageous 
use in electrophotographic printing applications from an electronically 
stored original. 
A reproduction machine in which the present invention finds advantageous 
use utilizes a photoreceptor belt 10. Belt 10 moves in the direction of 
arrow 12 to advance successive portions of the belt sequentially through 
the various processing stations disposed about the path of movement 
thereof. 
Belt 10 is entrained about stripping roller 14, tension roller 16, idler 
rollers 18, and drive roller 20. Drive roller 20 is coupled to a motor 
(not shown) by suitable means such as a belt drive. 
Belt 10 is maintained in tension by a pair of springs (not shown) 
resiliently urging tension roller 16 against belt 10 with the desired 
spring force. Both stripping roller 18 and tension roller 16 are rotatably 
mounted. These rollers are idlers which rotate freely as belt 10 moves in 
the direction of arrow 16. 
With continued reference to FIG. 1, initially a portion of belt 10 passes 
through charging station A. At charging station A, a pair of corona 
devices 22 and 24 charge photoreceptor belt 10 to a relatively high, 
substantially uniform negative potential. 
At exposure station B, an original document is positioned face down on a 
transparent platen 30 for illumination with flash lamps 32. Light rays 
reflected from the original document are reflected through a lens 34 and 
projected onto a charged portion of photoreceptor belt 10 to selectively 
dissipate the charge thereon. This records an electrostatic latent image 
on the belt which corresponds to the informational area contained within 
the original document. 
Thereafter, belt 10 advances the electrostatic latent image to development 
station C. At development station C, a magnetic brush developer unit 38 
advances a developer mix (i.e. toner and carrier granules) into contact 
with the electrostatic latent image. The latent image attracts the toner 
particles from the carrier granules thereby forming toner powder images on 
photoreceptor belt 10. 
Belt 10 then advances the developed latent image to transfer station D. At 
transfer station D, a sheet of support material such as paper copy sheet 
is moved into contact with the developed latent images on belt 10. First, 
the latent image on belt 10 is exposed to a pre-transfer light from a lamp 
(not shown) to reduce the attraction between photoreceptor belt 10 and the 
toner powder image thereon. Next corona generating device 40 charges the 
copy sheet to the proper potential so that it is tacked to photoreceptor 
belt 10 and the toner powder image is attracted from photoreceptor belt 10 
to the sheet. After transfer, a corona generator 48 charges the copy sheet 
to an opposite polarity to detack the copy sheet for belt 10, whereupon 
the sheet is stripped from belt 10 at stripping roller 14. 
Sheets of support material are advanced to transfer station D from supply 
trays 50, 52 and 54, which may hold different quantities, sizes and types 
of support materials. Sheets are advanced to transfer station D along 
conveyor 56 and rollers 58. After transfer, the sheet continues to move in 
the direction of arrow 60 onto a conveyor 62 which advances the sheet to 
fusing station E. 
Fusing station E includes a fuser assembly, indicated generally by the 
reference numeral 70, which permanently affixes the transferred toner 
powder images to the sheets. Preferably, fuser assembly 70 includes a 
heated fuser roller 72 adapted to be pressure engaged with a back-up 
roller 74 with the toner powder images contacting fuser roller 72, In this 
manner, the toner powder image is permanently affixed to the sheet. 
After fusing, copy sheets bearing fused images are directed through 
decurler 76. Chute 78 guides the advancing sheet from decurler 76 to catch 
tray 80 or a finishing station for binding, stapling, collating etc. and 
removal from the machine by the operator. Alternatively, the sheet may be 
advanced to a duplex tray 90 from duplex gate 92 from which it will be 
returned to the processor and conveyor 56 for receiving second side copy. 
A pre-clean corona generating device 94 is provided for exposing the 
residual toner and contaminants to positive charges to thereby narrow the 
charge distribution thereon for more effective removal at cleaning station 
F, more completely described hereinafter. It is contemplated that residual 
toner remaining on photoreceptor belt 10 after transfer will be reclaimed 
and returned to the developer station C by any of several well known 
reclaim arrangements, and in accordance with the present invention, 
described below. 
As thus described, a reproduction machine in accordance with the present 
invention may be any of several well known devices. Variations may be 
expected in specific processing, paper handling and control arrangements 
without affecting the present invention. 
In accordance with the invention, and with reference to FIGS. 1 and 2, 
cleaning station F generally includes a cleaning blade 100 supported in 
blade support 102 for cleaning engagement with photoreceptor belt 10 for 
the chiseling removal of toner from photoreceptor belt 10 within housing 
103. Blade 100 may advantageously be a thin urethane member having a 
rectangular cross-section, and supported in slightly deforming engagement 
with the photoreceptor belt 10. Supported slightly upstream and generally 
parallel to blade 100 across photoreceptor belt 10 is foam auger member 
104 arranged for abrading contact with the belt 10. As better shown in 
FIG. 3, foam auger member 104 is a generally spiral shaped member, 
including an auger shaft 106 journaled for rotating movement by a motor or 
drive means (not shown). The spiral movement of the auger member as driven 
by the drive means carries toner along its length to the side edge of the 
photoreceptor. The foam auger surface 108 in contact with photoreceptor 
belt 10 is provided with a large number of pores 109 which serve to 
collect toner for abrasion of the photoreceptor. The rotating motion of 
the auger serves to carry toner to the edge of the photoreceptor belt 10 
to any of several types of toner transport. As the auger rotates, contact 
between the auger and the photoreceptor provides a slight abrasion 
desirable for cleaning toner film from the surface of the photorecptor. 
Advantageously, because of the spiral shape of the auger, the 
photoreceptor surface is not continuously abraded, as with a foam roll 
cleaner, thereby reducing the wear on the surface, while still providing 
satisfactory cleaning operation. While the auger edges 110 are shown to be 
square, beveled or rounded edges may be desirable depending on the 
material used and the force with which the auger contacts the 
photoreceptor belt 10. Foam material choices include polyester urethane 
and polyether urethane, which have a reticulated open cell structure, 
between 35.100 pores/linear inch, and low set, high resilience, with HR 
values of 2, 4 or 6. Other material having these characteristics may also 
be suitable. While microcellular material having greater than 100 
pores/linear inch may also be useful, it is believed that the pores will 
be too small for collection of toner. Foam felts or compressed foams may 
also be useful, with firmness values of 2-10, and having about 80 
pores/inch. Foam materials, either with abrasive materials such as silica 
or alumina distributed through the material or with abrasive materials 
glued to surface 108 of the auger contacting photoreceptor belt 10 may 
also be suitable for use. 
The auger member is rotated to minimize debris such as paper fiber slipping 
by the member. The rate of toner removal from the toner pile in front of 
the blade must be fast compared to the time for incoming debris to reach 
the blade cleaning edge. The reduction of loose debris reaching the 
cleaning blade will have a significant effect on cleaning efficiency. 
In accordance with another embodiment of the invention, and as shown in 
FIG. 4, auger 120 may instead be a metal member provided with a relatively 
sharp edge 122 which scrapes the photoreceptor surface free of toner film. 
In accordance with this embodiment, the auger is operable in the same 
fashion to remove toner collecting adjacent to the blade, but is arranged 
to lightly scrape the surface with the sharp edge 122. While the auger 
edge 122 is illustrated as a knife edge beveled on both sides 124 and 126 
of auger edge 122, various other edges might be provided to achieve 
similar results, such as for example, a single beveled edge, on the side 
in the direction of toner movement. Desirably the metal is a non-ferrous 
material to avoid rusting. The auger edge 122 may be roughed. 
In accordance with yet another embodiment of the invention as shown in FIG. 
5, auger 130 may be manufactured from a polymeric or plastic material in 
which the surface 132 in contact with the photoreceptor may be slightly 
roughened to provide an abrading contact with photoreceptor belt 10. 
Polypropylene, polycarbonate, and ultra high molecular weight polyethylene 
are among the materials suitable for use. The materials may be provided 
with abrasive filler such as, for example, silica, calcium carbonate, 
carbides, nitrides, phosphates, glass fibers, or carbon fibers at filler 
concentrations of about 5-30%. The abrasive material itself may provide a 
satisfactory roughening of the surface 132. 
The invention has been described with reference to a preferred embodiment. 
Obviously modifications will occur to others upon reading and 
understanding the specification taken together with the drawings. This 
embodiment is but one example, and various alternatives modifications, 
variations or improvements may be made by those skilled in the art from 
this teaching which are intended to be encompassed by the following claims 
.