Note: Descriptions are shown in the official language in which they were submitted.
2125303
REMOVABLE E~ROCESS UNIT WITH WASTE TONER STORAGE
B~4CKGROUND OF THE INVENTION
The preseni~ invention is directed to a removable process unit for
use in electrostatographic printing apparatus and in particular to a cover
for such a removable process unit having a cavity for the storage of toner
cleaned from a photoreceptor.
Recently there has been a tendency in the design of
electrostatographic printing apparatus to place one or more of the
functional units such as a photoconductor drum or developer housing in a
removable processing cartridge or unit so that the customer or operator of
the printing machine may replace a functional unit when it's lifetime has
been exhausted or a different processing parameter such as toner color is
desired. Exemplary of such machines are those described and illustrated,
for example, in U.S. Patent 3,985,436 to Tanaka et al., 4,556,308 to Hoppner
et al. and 5,111,246 to Brailsford et al.
Accordingly, the removable
processing cartridges may be designed to contain a photoreceptor, a
developing device, a~ cleaning device as well as a charging device.
Alternatively, instead of placing all of the functional elements in a single
processing cartridge there may be two or more processing cartridges
wherein, for example, the photoreceptor, cleaning device and charge
device are in one rennovable processing cartridge while the developer
device is in another removable processing cartridge.
There is a desire, particularly with the smaller
electrostatographic printing machines, to make these removable process
units or cartridges as small as possible. Accordingly, the capacity of a
cleaner sump, for ex;~mple, in such a removable process unit may be
diminished to accommodate this desire for compactness. As a result the
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capacity to store cleaned toner in such a removable process unit is
somewhat limite~~ and is particularly limited where the process unit is being
used in an extended life environment wherein it is used until something in
it fails rather than being used for only a stated number of prints. As
illustrated in Figure 1, one way of providing additional capacity for the
storage of cleaned toner in the past has been to transport cleaned toner
from the cleaner sump 10 to the interior of the photoreceptor drum 12.
Typically, the transport has been accomplished with the use of a flexible
auger 13 within ;~ flexible tube 14 which turns 180 degrees in transporting
the toner from the cleaner sump to the interior of the photoreceptor drum.
This type of device is difficult to assemble due to the number of parts) their
flexible nature and the required side assembly motions. Moreover, it is
difficult in many instances to reuse the drum since it is difficult to remove
the toner from the interior of the drum without damaging the sensitive
photoreceptor surface. Because of the number of parts including a flexible
auger and a flexible tube as well as mounting seals and the side assembly
the process unit is relatively expensive. In addition, when the drum
becomes full of goner the auger continues to rotate and backs out of the
drum forcing itself into a twisted knot which may damage the auger and
drive mechanism.
SUMMARY OF THE INVENTION
The present invention is directed to a removable process unit for
an electrostatoclraphic printing machine wherein there is additional
capacity to store waste toner cleaned from the photoreceptor surface. In
particular, the process unit cover on one end of the process unit has a waste
toner storage cavity for the storage of toner therein.
In a specific aspect of the present invention a removable process
unit for an electrostatographic printing machine comprises a
photoreceptor, ~~ frame having a longitudinal axis including means to
movably mount the photoreceptor therein along said axis, a cleaning sump
extending along the longitudinal axis and adjacent the photoreceptor,
means to transport toner cleaned from the photoreceptor toward one end
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of the sump, the sump having an aperture at that end and a cover for the
frame at that end of the sump including a cavity with an aperture in
communication with the aperture in the sump for the transport of cleaned
toner into said cavity for storage.
In a further aspect of the present invention the cover has at least
one hand indent to facilitate insertion and withdrawal of the removable
process unit from a printing machine.
In a further aspect of the present invention the hand indent
comprises a ribbed thumb indent on the top portion of the cover and a
finger grip indent on the bottom portion of the cover.
In a further aspect of the present invention the photoreceptor is
a rotatably mounted cylindrical drum having a photoconductive insulating
surface.
In a further aspect of the present invention the toner is
transported in said cleaning sump to said one end by a rotatably driven
auger which is driven through a slip clutch which drives the auger until the
torque reaches a level representing that the cavity is full.
In a further aspect of the present invention an automatic
printing machine has a lower base mounting frame and an upper mounting
frame for mounting the functional components of the machine. The upper
mounting frame is mounted for upward movement about one end thereof
to one end of the lower frame in a clam shell-like manner and the
removable processing unit is mounted in the upward frame whereby when
the upward frame is pivoted upwardly the cavity is oriented at an angle
such that toner automatically falls by gravity away from the aperture in the
cavity.
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Further aspects of the present invention are as follows:
A removable process unit for an electrostatographic printing machine
comprising a photoreceptor, a frame having a longitudinal axis including
means to movably mount said photoreceptor therein along said longitudinal
axis, a cleaning toner sump extending along said longitudinal axis and
adjacent said phatoreceptor means to transport toner cleaned from said
photoreceptor toward one end of said sump, said toner sump having an
aperture at said one end, a cover for said frame at said one end thereof, said
cover including a cavity with an aperture in communication with said aperture
in said sump for the transport of cleaned toner into said cavity for storage.
An automatic printing machine comprising means for forming an
electrostatic latent image on a photoreceptor, means to develop said image
with toner, means to transfer said toner image to a receiving sheet and fix it
thereto and wherein some of said machine elements are assembled in a
removable processing unit, said removable processing unit comprising a
photoreceptor, a frame having a longitudinal axis including means to movably
mount said photoreceptor therein along said longitudinal axis, a cleaning
toner sump extending along said longitudinal axis and adjacent said
photoreceptor means to transport toner cleaned from said photoreceptor
toward one end of said sump, said toner sump having an aperture at said one
end, a cover for said frame at said one end thereof, said cover including a
cavity with an aperture in communication with said aperture in said sump for
the transport of cleaned toner into said cavity for storage.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is an exploded isometric view of a removable process unit
according to the prior art.
Figure 2 is an exploded isometric view of the removable process unit
according to the present invention.
Figure 3 is an enlarged isometric view of the process unit cover
according to the present invention.
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Figure 4 is a cross sectional view of a removable process unit.
Figure 5 is a schematic cross sectional view of an automatic
electrostatographic printing machine with a removable process unit
according to the present invention wherein the upper and lower mounting
frames are in the open position.
DESCRIPTION OF PREFERRED EMBODIMENT
The invention will now be described with reference to the
preferred embodiment of the removable process unit. Turning now to
Figures 2, 3 and 4 the removable processing cartridge or unit 1 S has a frame
16 having a longitudinal axis 17 in which a photoreceptor drum 19 having a
photoconductive insulating surface 20 is rotatably mounted along a
longitudinal axis 17 in the frame 16. The drum is rotatably driven in the
indicated direction (See Figure 4) by means not shown. The charging
station 38 includes the charge corotron 39 in a corotron grid 40 (see Figure
4). The cleaner assembly 43 to the rear of the photoreceptor drum 19
includes a cleaning blade 44 mounted on a supporting bracket 45, a
disturber brush 4~6 to disturb toner on the photoreceptor drum prior to it
being cleaned from the surface by the cleaning blade and a flicker bar 47 to
flick the toner that may agglomerate on the disturber brush. There is a
paddle wheel 50 to transport toner to the rear of the waste toner sump 51
which is parallel to, the longitudinal axis 17 of the frame 16 where an auger
52 which is rotat<~bly driven through a slip clutch 60 (see Figure 2) drives
toner toward one end, the outboard end, of the cleaner sump 51.
At the ~~utboard end of the cleaner sump, there is an aperture 61
which is in toner conveying communication with an aperture 62 in the
process unit cover 65 (See Figure 3) on the outboard end of the process unit.
The process unit cover 65 illustrated in Figure 3 is made of two molded
pieces which are ultrasonically welded together, a substantially flat bottom
and a shaped top which define a toner storage cavity 66 in between. On
the top of the process unit cover 65 is a hand indent 67 having ribs 68 to
provide a thumb hold. As seen in Figure 3 on the bottom of the cover is a
finger indent 69 i:o further facilitate insertion and withdrawal of the unit
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from the printing machine. The ribs 70 at the top of the cover are a catch
far a latch in the main machine for holding the process unit in place. The
auger is rotatably driven through a slip clutch 60 on the inboard end of the
removable process unit. The auger 52 is driven through the slip clutch 60
until the torque reaches a level representing that the cover is full of toner
and while the gear keeps rotating, the auger stops and therefore stops
trying to transport further toner to the cavity in the process unit cover. As
a
result, once the cavity in the process unit cover is filled additional waste
toner is collected in the cleaner sump.
Figure S is a representation of a typical machine in which the
removable process unit may be used. This automatic printing machine 71
comprises a lower base mounting frame 72 and an upper mounting frame
73 pivotally mounted about one end 74 in a clam shell-like manner. The
various functional elements used in making a print, are mounted to either
the upper or the lower frame members. Typically, the machine is opened
by pivoting the upper mounting frame about the one end to expose certain
of the functional elements and in particular the paper path to clear a paper
jam. As illustrated in Figure 5, when the upper mounting frame 73 is
pivoted to the open position the cavity in the process unit cover is oriented
at an angle such that waste toner in the cavity 66 automatically falls by
gravity to the remote end of the cavity from the toner entry aperture 62,
thereby ensuring a more completely filled cavity in the process unit cover
and a more even distribution of toner in the cavity.
Thus, according to the present invention a new removable
process unit with increased storage capacity for waste toner has been
provided. In particular, the present design has the advantage of requiring
fewer parts, eliminating flexible parts that require manual and side
assembly and facilitates automated top down assembly thereby providing a
less expensive simple process unit. In addition, since toner is not stored in
the photoreceptor drum there is the opportunity to reuse the
photoreceptor in the same or other process unit.
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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. Accordingly,
it is intended to embrace all such alternatives and modifications as may fall
within the spirit and scope of the appended claims.
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