Cleaning apparatus for copy machines

The present invention concerns a thin plate disposed in contact with the surface of a photosensitive drum of a copying machine for guiding toner scraped from the drum surface into a recovery area of the machine; more particularly, it provides for automatic disengagement of the thin plate from its normal contact with the drum surface whenever the drum is not fully engaged within the machine, as during removal and subsequent return for jam clearing or maintenance operations, so as to prevent inadvertent damage to the drum or to the thin plate in the course thereof.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to an apparatus for cleaning an electrophotographic 
copying or like machine and particularly to a cleaning apparatus having a 
thin plate capable of guiding toner scraped from a photosensitive 
element-supporting drum by a cleaning blade. 
2. Description of the Prior Art 
In an apparatus for cleaning a drum surface of an electrophotographic 
copying or like machine by using a blade cleaning method, it is known to 
recover toner scraped from the circumferential surface of a photosensitive 
or photoconductive drum in a storage portion of the apparatus. Generally, 
a thin plate is applied to the circumferential surface of the drum so that 
the toner scraped therefrom may be guided for recovery by the presence of 
the thin plate. 
In an electrophotographic copying or like machine, the photosensitive drum 
must often be detached from the apparatus, when either a transfer sheet 
becomes jammed between portions of the apparatus during a copying 
operation or for performing maintenance on or supervising operation of the 
machine, as is well known. In that case, it has heretofore been the usual 
practice to detach and subsequently reattach the drum from and to the 
machine after first drawing the aforesaid thin cleaning plate away from 
the drum surface by means of one's fingertip or the like. However, this 
method or construction is disadvantageous in that the circumferential 
surface of the drum may be easily damaged by the thin plate or the thin 
plate damaged by the drum surface through inadvertent carelessness in 
effecting the removal or return of the drum. 
SUMMARY OF THE INVENTION 
In order to avoid accidental damage of the thin plate caused by careless 
handling, the present invention proposes a cleaning apparatus for a 
copying or like machine having a thin plate applied elastically to the 
surface of a photosensitive drum and capable of guiding toner scraped from 
the drum surface through gravity-induced descent. A member responsive to a 
drum attachment or detachment operation is provided whereby the thin plate 
may be operatively drawn apart from the drum surface by the functioning of 
the member. 
The present invention is described below in detail with reference to an 
embodiment thereof shown in accompanying FIGS. 1 and 2.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
The example illustrated shows a major portion of an electrophotographic 
copying machine as being provided with a photosensitive drum 3 set in a 
supporting member 1 so as to be attachable and detachable, together with 
supporting member 1, to or from a body frame 2. The supporting member 1 is 
equipped with a pair of end plates 7, 8 spaced from each other by a 
spacing bar 4, and further with a rod 5 and a substantially U-shaped frame 
6. The photosensitive drum 3 is mounted between front end plate 7 and rear 
end plate 8, while supporting member 1 is attached to body frame 2 through 
an attaching opening 10 formed in body frame 2 and a rail 9 that guides 
U-shaped frame 6. 
Cleaning apparatus A according to the present invention is positioned in 
face-to-face relation with the circumferential surface of photosensitive 
drum 3 and is set in body frame 2 as shown in FIG. 1. Referring now to 
FIG. 2, the cleaning apparatus is equipped with recovery or storage box 11 
having an opening located in face-to-face relation with a portion of the 
circumferential surface of photosensitive drum 3. Within recovery box 11 
are provided a cleaning blade 12 and a thin plate 13 formed of an elastic 
material such as polyester film or the like, the thin plate being disposed 
for guiding--in downward, falling travel--toner scraped from the surface 
of drum 3 by cleaning blade 12. Blade 12 is fixed at its base portion to 
the tip of an arm 15 secured to a frame 14 within recovery box 11, the tip 
edge 12a of the cleaning blade being operatively positioned in contact 
with the circumferential surface of drum 3. Thin plate 13 is fixed at an 
intermediate or middle portion thereof to one end 17a of a rotatable or 
movable holding member 17 supported axially by a pivot 16; one end (the 
front edge) 13a of the thin plate is normally elastically applied to the 
circumferential surface of photosensitive drum 3. Holding member 17 is in 
fact provided at both the front and rear sides, both portions thereof 
being unitarily formed and connected by a connecting member (not shown). 
Furthermore, the other or opposite end 13b of thin plate 13 is placed on a 
bottom wall 11a of recovery box 11. As a consequence, toner scraped from 
the surface of drum 3 by cleaning blade 12 travels or falls along thin 
plate 13 to bottom recovery wall 11a and is then discharged therefrom by a 
screw conveyer 18 set in the bottom portion of recovery box 11. 
A driven lever 20 axially supported at one end about an axis 19 is also 
positioned in recovery box 11. Arm 20a of driven lever 20 extends 
outwardly of recovery box 11 through a window or slit 21 therein. A driven 
or follower roller 22 provided at the tip of arm 20a is in operative 
contact with an action piece 23 mounted on front end plate 7. Driven lever 
20 is normally urged by a biasing member or spring 24 for movement in the 
counterclockwise direction (FIG. 2) and further includes an operating 
piece 20b projecting at substantially a right angle at the top end 
thereof; operating piece 20b is disposed in face-to-face relation with an 
end portion 17b of holding member 17. 
Action piece 23 serves to rotate driven lever 20 in the clockwise direction 
(FIG. 2) through driven roller 22 so that end 13a of thin plate 13 is 
moved into contact with the surface of drum 3 when the drum is installed 
at its predetermined position in the machine. 
When drum 3 is fully mounted or installed at its predetermined position in 
the copying machine, driven roller 22 is pushed upward by action piece 23 
to the solid line position seen in FIG. 2, whereby driven lever 20 is 
rotated in the clockwise direction against the urgency of spring 24. As a 
consequence, operating piece 20b of driven lever 20 is carried away from 
holding member 17 and tip end 13a of thin plate 13 is brought elastically 
into contact with the circumferential surface of drum 3. 
When supporting member 1 or drum 3 is slightly withdrawn from the body 
frame 2, on the other hand, action piece 23 is moved away from driven 
roller 22 and driven lever 20 is rotated counter-clockwise by the force or 
urgency of spring 24 to the imaginary or dotted line position shown in 
FIG. 2. As a result, end 17b of holding member 17 is forced downward by 
operating piece 20b and thereby shifted to the dotted line position shown 
in FIG. 2 whereby the tip 13a of thin plate 13 is withdrawn from the 
surface of drum 3. This withdrawn state of thin plate 13 is maintained 
until the drum is fully mounted or seated on body frame 2, and thus the 
possibility of damage to the thin plate 13 resulting from carelessness in 
the drum removal or return operations is virtually eliminated. 
As is clear from the foregoing explanation, the present invention provides 
positive avoidance of damage to the thin plate and to the drum caused by 
carelessness since withdrawal and contact of the thin plate with respect 
to the drum surface is carried out automatically in response to attachment 
and detachment of the drum.