Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
10623Z5
This invention relates to an improved photoconductor
drum cleaning apparatus for use with an electrostatic copier.
There exist, in the prior art, a number of systems de-
signed to remote toner particles and other materials which
accumulates on the photoconductive imaging surface and which,
if allowed to remain on the imaging surface, may degrade image
quality or damage the surface. Generally, these systems com-
prise belts, rollers, blades, and the like. While these systems
have enjoyed some success, they have generated their own problems,
one of which is buildup of toner fluid or other material on the
cleaning surfaces themselves. This buildup impairs cleaning
action of the system and may in time damage the photoconductive
surface.
Summary of the Invention
- One object of the invention is to provide a photocon-
ductor drum cleaning apparatus which effectively cleans the
photoconductor surface.
Another object of the invention is to provide a photo-
conductor drum cleaning apparatus which does not scratch the
photoconductor surface.
A third object of the invention is to provide a photo-
conductor drum cleaning apparatus which resists clogging.
A fourth ob~ect of the invention is to provide a photo-
24 conductor drum cleaning apparatus which is simple and compact.
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Other and furtllcr objecLs of the invention ~7il
appear from the following description:
The invention relates to apparatus for cleaning
a moving imaging surface including in combination, squeegee
blade means having a pair of spaced parallel elongated
portions having edges, means for supporting the blade means
with the elongated portions extending across the imaging
surface with the edges èngaging the surface along spaced
parallel lines of contact, and means for effecting lengthwise
movement of the elongated portions in opposite directions
along the l-~nes of contact.
In general the invention contemplates a photo-
conductor drum cleaning apparatus comprising a rotating foam
roller and a self-cleaning squeegee blade sequentially
arranged adjacent to and in contact with the photoconductor
surface at a location beyond that at which image transfer
takes place and ahead of the charging station. The foam
roller, which counter rotates with respect to the photo-
conductor at their line of tangency, is continually supplied
with developer liquid to keep its surface wet. The self-
cleaning squeegee blade is formed by a driven endless rubber
or polyurethane belt supported by pulleys located outboard
of the drum so that the belt extends completely across the
photoconductor surface. The belt is so disposed as
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to contact the photoconductor surface at an angle to a tangent
to the drum so that an edge portion of the belt engages the
photoconductor surface. The endless belt is itself cleaned
as it is driven past a cleaning station located away from
the photoconductor surface. In various embodiments of the
invention, the endless belt contacts the photoconductor
surface at a right angle or at an acuate angle to a tangent
to the photoconductor surface.
The cleaning apparatus substantially avoids the
problem of cleaning system clogging and the attendant risk of
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damage to the photoconductor surface. The foam roller,
which counterrotates with respect to the photoconductor
surface and is continually irrigated with liquid developer
provides the basic cleaning action. The self-cleaning
squeegee blade enhances the cleaning action and, in addition,
wipes the photoconductive surface dry. Because the
squeegee blade is itself being continually cleaned by its
auxiliary cleaning system, there is little danger of toner
buildup on the blade scratching the photoconductor surface.
While the preferred embodiment of our invention is described
in relation to a copying machine employing a drum, our
cleaning apparatus is equally adaptable to a machine em-
ploying a photoconductor surface of the endless belt type.
Brief DescriPtion of the Drawings
.,
- In the accompanying drawings which form part of the
instant specification and which are to be read in conjunction
therewith and in which like reference numerals are used to
indicate like parts in the various views:
FIGURE 1 is a rear elevation of our cleaning
apparatus, with parts broken away.
PIGURE 2 is a section of our cleaning apparatus
taken along line 2-2 of FIGURE 1.
FIGURE 3 is a top plan of the roller subassembly
of our cleaning apparatus, with parts broken away.
~: FIGURE 4 is a side elevation of the blade assembly
of our cleaning apparatus.
FIGURE S is a bottom plan of the blade assembly
shown in FIGURE 4.
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FIGURE 6 is a section of the blade assembly of
our cleaning apparatus taken along line 6-6 of FIGURE 1.
FIGURE 7 is a section of an alternative embodiment
of the blade assembly which contacts the photoconductor
surface along one transverse only.
Description of the Preferred Embodiments
Referring to FIGURES 1 through 6, the cleaning
system, indicated generally by the reference character 10,
includes a cylindrical roller 12 having a cylindrical
aluminum core 14 and a covering layer 16 of polyurethane
foam or the like. The roller 12 is mounted on stub shafts
, 18 and 20 which are supported by bearings 22 and 24, located
respectively in roller support brackets 26 and 28. When
in use, the roller 12 contacts the photoconductive surface
30 of the drum 32 at a location between the image transfer
station and the charging station of the machine with which
it is used.
Pivot screws 38 and 40 mount the roller support
brackets 26 and 28 on cleaner support brackets 34 and 36
for movement of roller 12 toward and away from the surface
30 of drum 32. Tension springs 42 and 44 extending between
brackets 34 and 36 and brackets 26 and 28 urge roller 12 to
, move away from drum 32 to a limit position defined by adjusting
,, screw 46 and 48. Screws 46 and 48 can be manipulated to
adjust the position of roller 12 and thus the pressure
exerted by the roller on the surface 30 of drum 32. A pair
of rods 50 and 52, extending between the roller support
brackets 26 and 28 and cleaner support brackets 34 and 36
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10~2325
give the roller subassembly torsional rigidity.
Bearings 54 and 56 pivotally mount cleaner
support brackets 34 and 36 on a main drive shaft 58 which
is coupled to a driving motor (not shown). The entire
cleaning system 10 is thus mounted on the cleaner support
brackets 34 and 36. The cleaning system 10 is normally
urged against the drum surface 30 by means of a cam 53,
mounted on a shaft 55 which is pivotally received by end
support brackets 80 and 82 to be described, which cam
engages a stop 57, secured to the outboard side of cleaner
support bracket 36 by screws 59 or the like. When not in
use, the cleaning system may be retracted from the photo-
conductor surface 30 by rotating the cam 53 upward and
~- pivoting the system on shaft 58 away from the position shown.
An intermediate drive shaft 60 is rotatably or it
may be driven to reduce drag on roller 12. We position a
tray 88 below roller 87 to collect liquid being squeezed out
of roller 12. Tray 88 directs the collected liquid to one
side of the machine at which it may be fed back to the
developer supply system.
The wiper blade assembly of the cleaning system,
indicated generally by the reference character 90, includes
an endless belt 92 which is composed of nitrile rubber,
; polyurethane, or other developer carrier liquid resistant
flexible material. We stretch the belt 92 between two
pulleys 94 and 96 located outboard of the drum ends. In
the preferred embodiment of our invention, both traverses
of the belt 92 contact the photoconductor surface 30
generally perpendicularly across its width, as shown, providing
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additional cleaning action. We mount the pulleys 94 and 96
on shafts 98 and 100 supported by respective bearings 102
and 104 disposed in a pulley support bar 106. The pulley
support bar 106 is fixedly secured to cleaner supports
brackets 34 and 36 by any suitable means such as welding
or the like. Pulley shafts 98 and 100 are coupled to the
intermediate drive shaft 60 through respective sets of worm
gears, one of which is made up of a worm wheel 108 and a
worm 112 and the other of which is made up of a worm wheel
110 and a worm 114. The belt 92 is kept in substantially
perpendicular engagement with the photoconductor surface 30
by means of a guide bar 116 mounted beneath the support
bar 106 between the pulleys 94 and 96. The guide bar 116,
; made of a suitable low friction material such, for example,
as polytetrafluoroethylenecopolymer, has a generally
rectangular cross section, but is provided with grooves 118
and 120 adapted to receive the upper portion of the width
of the belt 92.
~; A pair of wiper blades 122 and 124 are urged into
J 20 contact with the endless belt 92 at the left end of its
circuit. These wiper blades remove the toner and other
material picked up by the endless belt 92, and are assisted
in their cleaning action by feed pipes 126 and 128, which
spray the surface of the belt 92 with ~ets of developer
~ liquid through exit orifices 130 and 132.
i Referring now to FIGURE 7, we show an alternative
~ embodiment of our blade assembly designed to contact the
-~ photoconductor surface along only one edge of the endless
belt. This embodiment is substantially identical to the
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1062325
first embodiment except that guide means, comprising an
inner guide wall 134 having an L-shaped cross-section and
an outer guide wall 136, encloses only one traverse of the
belt 92. The blade assembly 90 is also canted with respect
to the photoconductor surface 30 to provide a suitable
contacting angle. The contacting edge of the belt 92 may
be canted either into or against the direction of the
rotation of the drum 32.
In operation of our cleaning system 10, as the
drum 32 rotates in a counterclockwise direction as viewed
in FIGURE 2 to carry the surface from an image transfer
station into the cleaning system, the foam covered roller
12 which is rotating in a direction opposite to that of the
drum scrubs the surface to loosen adhering toner particles
- and the like. Developer flowing onto the roller 12 preveùts
agglomeration of toner particles on the roller. After the
surface 30 leaves the roller 12, it is engaged by an edge
portion or edge portions of belt 92 which act to complete
the cleaning process by removing any remaining toner particles
from the surface 30 while at the same time wiping the surface
dry. Any materials carried away from the surface 30 are
removed from the belt through the action of wipers 122 and
124 and the developer jets from pipes 126 and 128.
After the last copy from a given cycle of machine
operation, we continue the operation of the cleaning system
10 for from five to-ten seconds to clean the drum completely
and allow the belt and sponge roller to be thoroughly flushed
` with developer. Following this operation we continue driving
the sponge roller and the belt for approximately ten seconds
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1062325
with the flow of developer cut off. This permits the roller
to squeeze out excess liquid and the belt to clear excess
developer liquid from in front of the squeegee point. As
the machine stops the system 10 is lifted from the surface.
It will be seen from the foregoing description
that we have accomplished the objects of oùr invention. Our
cleaning apparatus effectively cleans the photoconductor
surface. It does not scratch the photoconductor surface.
Our eleaning apparatus resists clogging.
It will be understood that certain features and
subcombinations are of utility and may be employed without
reference to other features and subcombinations. This is
contemplated by and is within the scope of our claims. It
is further obvious that various changes may be made in
details within the scope of our claims without departing
from the spirit of our invention. It is, therefore, to be
understood that our invention is not to be limited to the
specific details shown and deseribed. Having thus described
; our invention, what we claim is:
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