U.S. patent number 3,640,523 [Application Number 05/074,349] was granted by the patent office on 1972-02-08 for copy sheet handling apparatus for electrostatic office copiers.
This patent grant is currently assigned to Pitney-Bowes, Inc.. Invention is credited to Christian A. Beck.
United States Patent |
3,640,523 |
Beck |
February 8, 1972 |
COPY SHEET HANDLING APPARATUS FOR ELECTROSTATIC OFFICE COPIERS
Abstract
A bellows, incorporated within a sheet feed roller, is actuated
by external actuating apparatus to create a partial vacuum at
suction ports in the feed roller periphery. A pivotal pressure pad
assembly momentarily presses a sheet stack against the ports,
leaving the top sheet adhered to the feed roller which is then
rotated to advance the separated top sheet to a prefeed position.
Additional actuating apparatus, operating on command, rotates the
feed roller through the remainder of a complete revolution to feed
the prefed sheet from the apparatus and to reorient the feed roller
for the next sheet separation and prefeed cycle.
Inventors: |
Beck; Christian A. (Ridgefield,
CT) |
Assignee: |
Pitney-Bowes, Inc. (Stamford,
CT)
|
Family
ID: |
22119088 |
Appl.
No.: |
05/074,349 |
Filed: |
September 22, 1970 |
Current U.S.
Class: |
271/96 |
Current CPC
Class: |
G03G
15/6502 (20130101); B65H 3/10 (20130101) |
Current International
Class: |
B65H
3/10 (20060101); G03G 15/00 (20060101); B65h
003/10 () |
Field of
Search: |
;271/27,28,62,11 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Wegbreit; Joseph
Claims
Having described the invention, what is claimed as new and desire
to secure by Letters Patent is:
1. Copy-sheet-handling apparatus for electrostatic copiers, said
apparatus comprising, in combination:
A. a tray for supporting a stack of precut copy sheets;
B. a roller mounted for rotation, said roller including:
1. means for retaining a copy sheet against the periphery of said
roller;
2. first and second drive-engagable means;
C. a carriage supporting the leading edge portions of the stacked
sheets, said carriage
1. adapted for movement from a first position remote from said
roller to a second position adjacent said roller to lift the stack
and press a surface portion of the top sheet thereof against said
retaining means;
D. sheet separation and prefeed control means operating in sequence
during each operating cycle to
1. position said carriage to its second position,
2. actuate said retaining means to retain the top sheet against the
periphery of said roller,
3. position said carriage to its first position to remove and
separate the underlying sheets from the top sheet of the stack,
and
4. engage said first drive-engagable means to rotate said roller
through a first predetermined increment of rotation and thereby
advance the separated top sheet to a prefeed position,
E. a pair of feed rollers stationed in the copy sheet feed beyond
said prefeed position; and
F. copy cycle feed control means operating upon the initiation of a
copy cycle to engage said second drive-engagable means and rotate
said roller through a second increment of rotation to feed a prefed
copy sheet from said prefeed position to the nip of said feed
roller pair.
2. The apparatus defined in claim 1, wherein said first and second
increments of roller rotation total 360.degree..
3. The apparatus defined in claim 2, wherein said roller further
includes detent means and said sheet separation and prefeed control
means and said copy cycle feed control means act on said detent
means to precisely define said first and second increments of
roller rotation.
4. The apparatus defined in claim 1, which further includes an
idler roller positioned to coact with said roller to feed a copy
sheet beyond said prefeed position.
5. The apparatus defined in claim 4, wherein the length of a copy
sheet exceeds the circumference of said roller, and said roller
includes a low friction surface segment angularly positioned to be
juxtaposed to said idler roller when said roller concludes said
second increment of rotation, whereby the trailing portion of the
copy sheet may be drawn through the nip of said roller and said
idler roller by said feed roller pair without rotating said
roller.
6. The apparatus defined in claim 1, wherein the operating cycle of
said sheet separation and prefeed control means is initiated during
the concluding portion of the operating cycle of said copy cycle
feed control means, said latter means including signal means for
initiating an operating cycle of said sheet separation and prefeed
control means.
7. The apparatus defined in claim 1, wherein
1. said sheet separation and prefeed control means includes:
a. a first shaft adapted to execute a complete revolution to define
an operating cycle thereof,
b. a first cam on said first shaft adapted to position said
carriage to its first and second positions,
c. a second cam on said first shaft adapted to actuate said
retaining means, and
d. a first segment gear on said first shaft engaging said first
drive-engagable means, and
2. said copy cycle control means includes:
a. a second shaft adapted to execute a complete revolution to
define an operating cycle thereof,
b. a third cam on said second shaft adapted to position said
carriage to its first and second positions,
c. a second segment gear on said second shaft engaging said second
drive-engagable means,
d. signal means for initiating an operating cycle of said sheet
separation and prefeed control means, and
e. a fourth cam on said second shaft adapted to actuate said signal
means during the concluding portion of the operating cycle of said
copy cycle feed control means.
8. The apparatus defined in claim 7, wherein said roller carries a
detent disc having first and second detents for defining first and
second angular detent positions for said roller, said apparatus
further including:
A. a pawl carried by a detent release arm, said detent release
arm
1. being actuated by said sheet separation and prefeed control
means to disengage said pawl from said first detent and release
said roller for rotation from said first detent position through
said first increment of rotation to said second detent position
where said pawl engages said second detent, and
2. being actuated by said copy cycle feed control means to
disengage said pawl from said second detent and release said roller
for rotation from said second detent position through said second
increment of rotation to said first detent position where said pawl
engages said first detent.
9. The apparatus defined in claim 7, wherein said second segment
gear disengages said second drive-engagable means before said
roller reaches said first detent position and said copy cycle feed
control means further includes resilient means engaging said detent
disc to rotate said roller to said first detent position.
10. The apparatus defined in claim 1, wherein said carriage
includes a stop element engaging the leading edges of the
underlying sheets of the stack during feeding of the separated top
sheet.
11. The apparatus defined in claim 1, wherein said retaining means
comprises negative pressure-generating means self-contained within
said roller for creating a suction at ports formed in the periphery
of said roller.
12. The apparatus defined in claim 1, which further includes
sensing means for detecting the presence of a sheet in the prefeed
position.
13. Copy-sheet-handling apparatus for electrostatic copiers, said
apparatus comprising, in combination:
A. a roller mounted for rotation, said roller including:
1. self-contained suction-generating means for creating a suction
force at a port formed in the peripheral surface thereof, and
2. first and second drive-engagable means;
B. a tray for supporting a stack of precut copy sheets;
C. a carriage movable toward and away from said roller and carrying
a pressure pad aligned with said port for lifting the stack to
press a surface portion of the top sheet into sealing relation with
said port;
D. sheet separation and prefeed control means operating said
carriage and said suction generating means to retain the top sheet
against said roller as said carriage is moved away from said roller
to separate the top sheet from the sheet stack and engaging said
first drive-engagable means to rotate said roller through a first
predetermined increment of rotation and thereby advance the
separated top sheet to a prefeed position;
E. copy cycle feed control means operating upon the initiation of a
copy cycle to engage said second drive-engagable means and rotate
said roller through a second increment of rotation to feed a prefed
copy sheet beyond its prefeed position; and
F. a pair of feed rollers engaging the leading edge of the prefed
copy sheet shortly before the conclusion of said second increment
of roller rotation.
14. The apparatus defined in claim 13, wherein said roller carries
detent means acted upon by said sheet separation and prefeed
control means and said copy cycle feed control means to define said
first and second increments of roller rotation, said first and
second increments of roller rotation totaling 360.degree..
15. The apparatus defined in claim 13, wherein said
suction-generating means comprises a bellows, said sheet separation
and prefeed control means acting on said bellows during the
operating cycle thereof to expand and compress said bellows to
create said suction force.
16. The apparatus defined in claim 14, wherein said roller carries
a resilient ring for coaction with an idler roller to feed a
separated top sheet, said port opening at the periphery of said
ring, the length of a copy sheet exceeding the circumference of
said roller, a low-friction surface segment imbedded in said ring
at an angular position to be juxtaposed with said idler roller when
said roller concludes said second increment of rotation, whereby
the trailing portion of the copy sheet may be readily drawn through
the nip of said ring and said idler roller by said feed roller pair
without rotation of said roller.
17. The apparatus defined in claim 16, wherein said copy cycle feed
control means further includes signal means actuated during the
concluding portion of the operating cycle thereof and after a copy
sheet has been drawn completely through the nip of said roller ring
and said idler roller to initiate an operating cycle of said sheet
separation and prefeed control means.
Description
REFERENCE TO RELATED APPLICATION
Reference is hereby made to the commonly assigned, copending
Schrempp and Beck application Ser. No. 74,364 entitled Sheet
Separation and Pre-Feed Apparatus, filed Sept. 22, 1970, wherein
apparatus herein disclosed is claimed.
BACKGROUND AND OBJECTS OF THE INVENTION
The current emphasis in office copier design is speed of operation.
Quite naturally, the faster a copier can produce copies the more
available it is to subsequent users. Also, a fast copier conserves
the time of the operator, who in a small office situation is
typically a secretary whose time is valuable. Not only is it
important that a copier produce multiple copies rapidly but also
that it be capable of producing a single copy without appreciable
delay. In a small office situation, probably the most common copy
run is that of a single copy.
An additional important design consideration is the size of the
copier. With office space so expensive, it is desirable that the
copier be reasonably compact. So called "desk copiers" are
available, however, when placed on a desk top such copiers take up
a considerable portion of the work surface.
One way in which to reduce the copier size is to go to precut copy
paper in lieu of roll copy paper which must be withdrawn and cut to
the size of the original sheet during each copy cycle. The precut
copy sheets are stacked on a tray or the like and must be
individually separated from the stack and fed seriatum through the
copier. Reliable separation of a single paper sheet from a stack is
not an easy task. If a single copy sheet is not successfully
separated and fed, the ensuing copy cycle is a complete waste of
time. Moreover, if separation and feeding is performed improperly,
the copy sheet may jam up somewhere along its feed path. The copier
must then be shut off and the jam cleared, which may require a
service call.
Another problem with the use of precut copy sheets is synchronizing
the sheet separation and feeding functions with the actual copying
process repeated during each copy cycle. To achieve requisite
synchronization, a "prefeed" technique is typically resorted to.
Generally, this involves separating a single sheet from a copy
sheet stack and advancing it to a fixed prefeed position at the
conclusion of each copy cycle. Thus, when a next copy cycle is
called for a copy sheet is already separated from its stack and is
fed through the various copy process station, starting from the
prefeed position. This simplifies the problem of synchronization
and also significantly shortens the time required for single copy
runs.
Accordingly, an object of the present invention is to provide
improved apparatus for handling precut copy sheets in an
electrostatic office copier.
A further object is to provide apparatus of the above character for
separating a copy sheet from a sheet stack, feeding the separated
copy sheet to a prefeed position, and thereafter, on command,
feeding the prefed copy sheet along the initial portion of its feed
path through the copier.
Yet another object is to provide apparatus of the above character
wherein the various copy sheet handling functions are coordinated
and controlled in an efficient and reliable manner.
An additional object is to provide apparatus of the above character
which is compact, inexpensive to manufacture, reliable and fast in
operation.
Other objects of the invention will in part be obvious and in part
appear hereinafter.
The invention accordingly comprises the features of construction,
combination of elements, and arrangement of parts which will be
exemplified in the construction hereinafter set forth, and the
scope of the invention will be indicated in the claims.
SUMMARY OF THE INVENTION
In accordance with the present invention, there is provided a
self-contained feed roller structure which is externally actuated
to effect separation of the top sheet of paper or the like from a
sheet stack and to feed the separated sheet to a reference or
prefeed position. The feed roller has incorporated therein a
compressible bellows which is in communication with one or more
suction ports in the feed roller surface. The bellows, by virtue of
its inherent resiliency, normally assumes a distended condition and
is compressed by external actuator means. While the bellows is
compressed, the paper sheet stack is elevated so as to bring the
top most sheet into sealed contacting engagement with the roller
surface surrounding the suction ports. The compacting pressure on
the bellows is then released, thereby creating a partial vacuum
sufficient to hold the top sheet against the feed roller. The sheet
stack is then lowered, thereby separating the stack from the top
sheet which remains adhered to the feed roller. The feed roller is
then rotated through a predetermined angle to advance the separated
sheet to a desired prefeed position.
The actuator means includes a first cam which is rotated to
compress and release the bellows within the feed roller. A second
cam is rotated in coordination with the first cam to effect the
raising and lowering of the sheet stack by a pivotal pressure pad
assembly in timed relation with the actuation of the bellows. Drive
means rotating in synchronism with the first and second cams
selectively engages the feed roller to effect the requisite
incremental rotation thereof for advancing the separated sheet to
the prefeed position. In addition, cam actuated detent means insure
that the feed roller is properly angularly oriented at the
conclusion of a sheet separation and prefeed operation.
Once the separated sheet has arrived at the prefeed position, it
must then be advanced or fed therefrom for processing. In the case
of an electrostatic office copier in which the apparatus of the
present invention is immenently applicable, the prefed copy paper
sheet is advanced through a charging station, an imaging station
and a developing station pursuant to reproducing on the copy sheet
the image borne by an original document sheet. The suction feed
roller also participates in the feeding of a separated sheet beyond
its prefed position. Separate drive means are provided for rotating
the feed roller through an angle which would return it to its
angular orientation at the beginning of a sheet separation and
prefeed operation. Incident to this second increment of feed roller
rotation, the previously prefed sheet is advanced by the feed
roller to a point where it is engaged by secondary feed rollers
operating to completely withdraw the sheet from the apparatus of
the invention. Cam means operating in synchronism with the second
drive means controls the elevational position of the sheet stack in
order that advancement of the prefed sheet beyond its prefeed
position will not disturb the stack and also controls the detent
means so as to insure that the feed roller is properly angularly
oriented for the initiation of the next sheet separation and
prefeed operation, which preferably occurs at the conclusion of a
copy cycle.
For a fuller understanding of the nature and objects of the
invention, reference should be had to the following detailed
description taken in connection with the accompanying drawings, in
which:
FIG. 1 is a longitudinal sectional view of an electrostatic
photocopier employing the apparatus of the present invention;
FIG. 2 is a perspective view of the sheet separation and prefeed
apparatus of the invention;
FIG. 3 is a front elevational view, partially broken away, of the
apparatus of FIG. 2;
FIG. 4 is a sectional view taken along line 4--4 of FIG. 3;
FIG. 5 is a longitudinal sectional view of the feed roller included
in the apparatus of FIG. 2;
FIG. 6 is a side elevational view, partially broken away, of one of
the pressure pads incorporated in the apparatus of FIG. 2;
FIG. 7 is a sectional view taken along line 7--7 of FIG. 3 showing
the positions of the various parts at the beginning of a sheet
separation and prefeed operation;
FIG. 8 is a sectional view taken along line 7--7 of FIG. 3 showing
the positions of the various parts upon achievement of separation
of the top sheet from the sheet stack;
FIG. 9 is a sectional view taken along line 7--7 of FIG. 3 showing
the positions of the various parts after the separated sheet has
been advanced to a prefeed position;
FIG. 10 is a sectional view taken along line 10--10 of FIG. 3
showing the detent means incorporated into the apparatus of the
present invention;
FIG. 11 is a fragmentary perspective view of the apparatus for
advancing a prefed sheet beyond its prefeed position;
FIG. 12 is a side elevational view of the actuating means
incorporated in the apparatus of FIG. 11; and
FIG. 13 is an end elevational view of the actuating means of FIG.
12.
Like reference numerals refer to corresponding parts throughout the
several views of the drawings.
DETAILED DESCRIPTION
Referring now to the drawings and first to FIG. 1, the apparatus of
the present invention is illustrated as being incorporated in an
electrostatic photocopier of the direct imaging type which employs
copy paper having a photoconductive coating thereon, such as
Electrofax paper. It will be appreciated, however, that the
apparatus of the present invention has application in other types
of office copiers as well as to sheet handling apparatus
generally.
As seen in FIG. 1, a stack 10 of precut copy sheets is supported on
a tray 12 with the leading edges of the stacked sheets positioned
adjacent the sheet-handling apparatus of the present invention,
generally indicated at 14. The sheet-handling apparatus 14 includes
a sheet separator and sheet feed roller 16 which, in a manner to be
described, is employed to separate the top sheet from the copy
sheet stack 10 and then advance the separated sheet to a prefeed
position where its leading edge is engaged between feed roller 16
and an idler feed roller 18. As will be seen, separation of the top
sheet from the sheet stack 10 is effected, in accordance with the
invention, by adapting the feed roller 16 with means for creating a
partial vacuum at suction ports formed in its peripheral surface. A
pressure pad assembly, generally indicated at 20, is actuated to
lift the leading edges of the stack 10 so that the upper surface of
the top sheet is pressed against the periphery of the feed roller
16 in sealing relation to the suction ports therein. A partial
vacuum is then created at these ports to adhere the top sheet to
the feed roller periphery which is then readily separated from the
rest of the stack 10 merely by pivoting the pressure pad assembly
20 away from the feed roller 16.
Once separation of the top sheet from the sheet stack 10 has been
effected, feed roller 16 is then driven through an increment of
rotation such that the leading edge of the separated sheet is
advanced through the nip of feed roller 16 and idler roller 18 to a
prefeed position. The presence of a prefed sheet is sensed by a
switch 22.
As contemplated by the present invention, sheet separation and
prefeed occurs at the conclusion of each copy cycle. Upon the
initiation of the next copy cycle, the prefeed sheet is then
advanced to and through the various copy processing stations. Thus,
as seen in FIG. 1, a prefed sheet, indicated at 24, is advanced
from its prefeed position by rotation of feed roller 16 through a
suitable corona charger 26. Rotation of feed roller 16 continues
until the leading edge of copy sheet 24 is engaged between a set of
feed rollers 28. During advancement of a prefed sheet beyond its
prefeed position, the sheet-handling apparatus 14 is controlled by
actuating means, generally indicated at 30.
To initiate operation of the actuating means 30, the copier is
turned on to provide continuous drive to feed rollers 32 positioned
in a document feed path. A document 36 to be copied is inserted
into the nip of feed rollers 32 and the passage of its leading edge
therebeyond trips a switch 34 which signals the actuating means 30
into operation. A prefed copy sheet 24 is then advanced by rotation
of the feed roller 16 through the corona charger 26 and its leading
edge arrives at the nip of feed rollers 28 substantially at the
same time as does the leading edge of the original document 36
being fed by feed rollers 32. The copy sheet 24 and the original
document sheet 36 then pass through an imaging station, generally
indicated at 38, where the copy sheet is selectively discharged by
light to transform the image borne by the original document to a
latent electrostatic image on the surface of copy sheet 24. From
the imaging station 38, the juxtaposed document sheet and copy
sheet are fed by feed rollers 40 to feed rollers 42 which are also
adapted to separate the sheets such that they may thereafter follow
separate paths. Immenently suitable juxtaposed sheet feeding and
separating apparatus is disclosed in copending application of Beck
and Tomasch entitled Separator for Juxtaposed Sheets, Ser. No.
23,215, filed Mar. 27, 1970 and assigned to the assignee of the
present application. The copy sheet 24 and the document sheet 36
are selectively acted upon by operation of the separator feed
rollers 42 to develop a separation therebetween, such that the
document sheet passes over a separator guide plate 43 while the
copy sheet passes under the separator guide plate. The document
sheet 36 follows a path defined by guide plates 44 for return to
the operator. The copy sheet 24 passes over a guide plate 45 to a
development station, generally indicated at 46, where the latent
electrostatic image carried thereby is developed into a visible
image. The developed sheet precedes along a path defined by guide
plates 48 for delivery to the operator.
The feed roller 16, as best seen in FIG. 5, consists of an
elongated cylinder 50 with a detent disc 52 secured in its left end
and an end cap 54 secured in its right end. A partition 56 is
secured within cylinder 50 by screws 57. A bellows 58, formed of a
suitable material such as metal, is mounted and hermetically sealed
at its left end to one side of partition 56. The other end of
bellows 58 is sealed off by an end plate 60. Bellows 58 is formed
such that it normally assumes an extended condition as indicated in
phantom.
A pair of tubular fittings 62 extend through partition 56 and
communicate with the interior of bellows 58. A pair of fittings 64
are secured in the wall of cylinder 50 and are coupled to fittings
62 by separate lengths of flexible tubing 66. The fittings 64 thus
provide ports 65 at axially aligned points in the periphery of
cylinder 50 which are in pneumatic communication with the interior
of bellows 58. It will be understood that while two ports 65 are
shown in the illustrated embodiment, an additional number of ports
may be provided. Also, a single port 65 may be sufficient for
effecting sheet separation and prefeed in the manner to be
described.
Still referring to FIG. 5, a rubber gripper ring 68, is carried by
the feed roller cylinder 50 at the axial location of each port 65.
In the vicinity of each fitting 64, the material of gripper ring 68
is removed and an insert 70 is substituted. Rubber gripper rings 68
are formed of a suitable durometer rubber or other elastomeric
material for proper sheet feeding coaction with idler roller 18
(FIG. 1). Insert 70 is preferably of a softer resilient material
than gripper ring 68 so that, in the manner to be described, the
top sheet of the sheet stack 10 is adequately sealed against the
material surrounding the ports 65 by operation of the pressure pad
assembly 20 (FIG. 1) at the time a negative pressure or suction is
created at the ports 65 by operation of the bellows 58. It will be
appreciated that certain elastomeric materials may be conducive to
both functions, thus eliminating the need for inserts 70.
Still referring to FIG. 5, the inserts 70 are apertured so as to
communicate with the ports 65 provided by fittings 64 and is also
recessed to provide a suction cuplike shape for improved adherence
of a paper sheet thereto upon actuation of the bellows 58.
As seen in FIGS. 3 and 5, a coaxial stub shaft 74, secured to
detent disc 52, serves to mount the left end of feed roller 16; the
shaft being journaled in an upright side frame 76 secured to a base
77. The other end of feed roller 16 is rotatably mounted by a
sleeve 78 secured in a central bore through end cap 54 and
journaled by a bushing 80 mounted by side frame member 82, also
secured to base 77 (FIG. 3). An elongated actuating pin 84 extends
through sleeve 78 with its left end fastened to end plate 60 of
bellows 58. Actuating pin 84 carries an integral cam follower disc
86 at a point beyond bushing 80; the cam follower disc being acted
upon by a sheet separation and prefeed actuating mechanism to be
described.
As previously noted, the bellows 58 is constructed such that its
normal unconstrained condition is that indicated in phantom in FIG.
5. When the bellows 58 is so extended, pin 84 and cam follower disc
86 are pushed to the right, assuming the phantom position shown in
FIG. 5. When the cam follower disc 86 is pushed to the left, pin 84
acts to compress the bellows 58. At this point, as will be seen,
the top sheet of the stack 10 is brought into sealing engagement
about ports 65, whereupon the bellows is released to assume its
extended position. This is effective to create a negative pressure
or suction at ports 65 sufficient to securely hold the paper sheet
thereto.
Turning now to FIG. 2, the sheet separation and prefeed-actuating
mechanism is generally indicated at 88. Mechanism 88 is powered
from a drive train consisting, in part, of gears 89 and 90, shaft
91 and gears 92 and 93 (FIG. 3) which are all driven as long as the
copier is turned on. A shaft 96 for gear 93 constitutes the input
shaft to a one revolution clutch 98 which is engaged by actuation
of a solenoid 100. Thus, each time the solenoid 100 is actuated, it
causes the clutch 98 to couple its input shaft 96 to its output
shaft 102 for one complete revolution, after which the two shafts
are decoupled. Output shaft 102 carries a radial disc cam 104, a
helical cam 106 and a disc 108 having a spur gear segment 110
formed in its periphery and an internal annular cam track 112 with
a raised cam segment 114 formed therein. It is thus seen that upon
engagement of clutch 98, cam 104, cam 106 and disc 108 are driven
through one complete revolution.
As seen in FIGS. 2 and 3, radial disc cam 104 acts on a cam
follower 116a carried by a cam follower arm 116 which is secured at
its lower end on a shaft 118 rotatably mounted by brackets 119
(FIG. 3). A hook-shaped actuator 120, secured on the left end of
shaft 118, acts on an actuator pin 122 to downwardly pivot a
carriage 124, included in the pressure pad assembly 20 (FIG. 1).
Carriage 124 is pivotally mounted on a fixed shaft 126, seen in
FIGS. 1 and 11. A spring 128 biases cam follower 116a against the
periphery of radial disc cam 104.
Still referring principally to FIGS. 2 and 3, the carriage 124
supports a pair of brackets 130, secured thereto by bolts 131. The
upper end of each bracket 130 is bent laterally outward so as to
support a pressure pad 132. As seen in FIG. 6, each pressure pad,
which is formed of a suitable material such as metal, has a
threaded shaft 132a which extends through a hole in the lateral
portion of bracket 130 and receives a nut 133 clamping the pressure
pad thereto. The face of each pressure pad is formed on a radius
corresponding to the radius of curvature of the gripper rings 68
(Fig. 2). A recess 132b is formed in the front surface of the
pressure pads so as to leave a rim 132c which acts as the pressure
transmitting surface for pressing the top sheet of the sheet stack
10 against the surface of insert 70 surrounding ports 65 (FIG. 5).
As is seen in FIGS. 1 and 7 through 9, the leading edges of the
sheet stack 10 lie in the area between feed roller 16 and the
pressure pads 132. The carriage 124 is normally urged toward the
feed roller 16 by springs 136 (FIG. 3). Thus, the pressure pads 132
engage the undersurface of the bottom sheet of the sheet stack and
lift the leading ends of the stacked sheets upwardly to bring the
upper surface of the top sheet adjacent its leading edge into
sealing engagement about the ports 65.
As is seen in FIG. 2, the carriage 124 carries lateral extensions
which are bent upwardly and extend toward the feed roller and curve
downwardly to provide outrigger elements 138 which act to support
the lateral edge portions of the sheet stack as the leading edge
portions therefore are lifted upwardly toward the feed roller 16 by
clockwise pivotal movement of the carriage 124. Outrigger elements
138 also serve as supports for stop elements 140 which extend
upwardly in abutting engagement with the leading edges of the sheet
stack 10. These stop elements 140 serve to prevent forward movement
of the underlying sheets in the sheet stack as the separated top
sheet is advanced to its prefeed position and beyond by rotation of
the feed roller 16.
Still referring principally to FIGS. 2 and 3, the helical cam 106
carried on shaft 102 acts on the cam follower disc 86 which was
described in connection with FIG. 5. In the positions of the
various parts shown in FIG. 2, which are their positions at the
beginning of each sheet separation and prefeed operation, the
trailing end 106a of helical cam 106, assuming counterclockwise
rotation thereof, engages the cam follower disc 86 thereby
compressing bellows 58 through actuating rod 84. This initial
condition is also seen in FIG. 4. After the helical cam 106 is
rotated through a small increment of counterclockwise rotation, cam
follower 86 is released, permitting the bellows 58 to extend,
thereby creating a suction at ports 65. It is seen that as helical
cam 106 continues to rotate, the leading, laterally offset end 106b
of the cam engages the cam follower disc 86 to cause the bellows 58
to be gradually compressed to the state shown in FIG. 5.
As is seen in FIG. 2, at the beginning of a sheet separation and
prefeed operation and before the bellows 58 is released by helical
cam 106, cam follower 116a is riding in the valley 104a of radial
disc cam 104. Actuator 120 is thus located and held in its extreme
clockwise position by spring 128, thereby permitting the carriage
124 to be positioned by spring 136 adjacent the feed roller 16 and
press the top sheet of the stack 10 into sealing relation with the
ports 65. The actuator 120 is oriented on its shaft 118 such that
the pressure pads 132 are always capable of pressing the top sheet
against the ports 65 regardless of the number of sheets in the
sheet stack 10. As cams 104 and 106 begin to rotate, the first
thing that happens is that the cam 106 releases the bellows 58
which then creates the suction at ports 65. The suction or negative
pressure at ports 65 is effective to hold the top sheet which is
pressed thereagainst by the pressure pads 132 acting through the
underlying sheets in the sheet stack. As the radial disc cam 104
continues to rotate, cam follower 116a rides out of valley 104a,
thereby causing cam follower arm 116 to rock counterclockwise
bringing actuator 120 into depressing engagement with the actuator
rod 122. The carriage 124 is then rocked in the counterclockwise
direction dropping the leading edges of the underlying sheets in
the sheet stack 10 away from the feed roller 16. The top sheet thus
becomes separated from the remainder of the stack by virtue of the
suction created at ports 65.
Having separated the top sheet from the sheet stack, it remains to
advance the separated sheet to a prefeed position. Prefeed is
accomplished by rotation of the feed roller by engagement with the
gear segment 110 formed on the periphery of disc 108 rotating with
cams 104 and 106 on shaft 102. Rather than have mating gear teeth
formed on the feed roller 16, it is preferred to provide a ring 150
of rubber or other suitable elastomeric material secured to end cap
54 (FIG. 5) which is engaged by the gear segment 110.
As the disc 108 rotates counterclockwise, a cam follower 152
carried by a cam follower arm 154 is rocked downwardly by cam
segment 114. The other end of cam follower arm 154 is secured on an
elongated shaft 156 which is appropriately mounted by means not
shown. The other end of shaft 156 carries a detent release arm 158
which supports at its free end a pawl 160 adapted to operate
against detent disc 52 secured to the left end of feed roller 16.
The detent disc 52, as best seen in FIG. 10, is formed having a
pair of radial walls 52a and 52b.
Returning to FIG. 2 it is seen that as disc 108 rotates
counterclockwise, cam follower arm 154 disengages the pawl 160 from
the radial wall 52a of detent disc 52. This frees the feed roller
16 for clockwise rotation as the gear segment teeth 110 bite into
the ring 150. Before the last tooth of gear segment 110 rotates out
of driving engagement with the ring 150, cam segment 114
terminates, thereby permitting the pawl 160 to rise back into
engagement with the periphery of detent disc 52 before it
encounters radial wall 52b; this movement being induced by return
spring 162. As radial wall 52b encounters pawl 160 to terminate
further rotation of feed roller 116, the last tooth of gear segment
110 still drivingly engages rubber ring 150. This insures that the
feed roller 16 is angularly oriented at the termination of the
prefeed operation precisely at the point where radial wall 52b is
engaged by pawl 160. It is for this reason that an elastomeric ring
150 is preferred over a gear ring as it would require stringent
manufacturing tolerances to insure that the gears disengage
precisely at the point where the pawl 160 engages the radial wall
52b of detent disc 52. It will be appreciated if the drive of feed
roller 16 terminates short of the detent position determined by
radial wall 52b, the separated sheet will not be prefed to the
desired prefeed position. On the other hand, if the drive
terminates after the tip 160 engages radial wall 52b, an
interference situation is created which would result in damage to
various parts of the apparatus. Rubber ring 150, however, yields to
release the last gear tooth of segment 110 as the pawl 160 inhibits
further feed roller rotation. This slippage insures proper angular
orientation of the feed roller at the conclusion of the prefeed
operation.
The positions of the various parts of the sheet handling apparatus
14 at various stages in the sheet separation and prefeed operation
are shown in FIGS. 7 through 9. In FIG. 7 the parts are shown in
their positions at the beginning of a sheet separation and prefeed
operating cycle, which positions are also illustrated in the
perspective view of FIG. 2. Thus, the pressure pads 132 are
pressing the leading edge portions of the sheet stack 10 against
the feed roller 16 under the force of the carriage springs 136
(FIG. 3). Solenoid 100 is pulsed and the one revolution clutch 98
is engaged to rotate its output shaft 102 through a complete
revolution. The first event is the creation of a suction at each of
the feed roller ports 65 caused by the disengagement of the helical
cam trailing edge 106a from the cam follower disc 86. As previously
noted, the bellows 58 springs to its extended condition; the
resulting internal expansion of the bellows being effective to
create the suction or negative pressure at ports 65. Thereafter,
radial disc cam 104 operates through cam follower arm 116 and
actuator 120 to pivot the carriage 124 downwardly to remove the
underlying sheets of the stack from the feed roller 16. The top
sheet 10a, however, is held against the feed roller ports 65 by the
suction thereat. This condition is shown in FIG. 8.
Also at this time, the cam segment 114 carried by disc 108 acts
through cam follower arm 154 and detent release arm 158 to remove
pawl 160 from engagement with the radial wall 52a of detent disc
52. The feed roller is thus free to be rotated by gear segment 110
in the clockwise direction through an angle A (FIG. 10) of
approximately 100.degree.. As seen in FIG. 9, the separated top
sheet 10a of the sheet stack 10 has been advanced through the nip
of idler roller 18 and the gripper rings 68 on feed roller 16 to a
prefeed position. During prefeed of the top sheet 10a, stop
elements 140 prevent the underlying sheets of the stack from being
dragged forward by prefeeding movement of top sheet 10a. Switch 22
is actuated by the top sheet as it is advanced to the prefeed
position and thus senses that a sheet has been successfully
prefed.
As the clutch output shaft 102 continues to rotate through the
remainder of its complete revolution, helical cam 106 reengages cam
follower disc 86 with its leading edge 106b to gradually compress
bellows 58. This action does not disturb the prefed top sheet 10a
since it is engaged in the nip of feed roller 16 and idler roller
18. As radial disc cam 104 continues to rotate through to the
conclusion of its complete revolution, cam follower 116a again
rides into valley 104a, whereupon the carriage springs 136 pivot
the carriage 124 in the clockwise direction bringing the pressure
pads 132 upwardly to press the underlying sheets of the sheet stack
against the feed roller 16. Thus, the carriage 124 assumes the
position shown in FIG. 7, while the feed roller 16 remains in the
orientation shown in FIG. 9.
Having successfully prefed a top sheet 10a, it now remains to
advance the prefed sheet on through the copier process stations and
also to return the feed roller 16 to its proper angular orientation
for the beginning of another sheet separation and prefeed
operation. To this end, the actuating means 30 mentioned in
connection with FIG. 1 and illustrated in detail in FIGS. 11
through 13 is uniquely adapted. As best seen in FIG. 13, the
actuating means 30 includes a drive pulley 170 which is
continuously rotated by a drive belt 172 for as long as the copier
is turned on. Pulley 170 is mounted on a shaft 174 which serves as
the input shaft to a one revolution clutch 176. The clutch output
shaft 178 is adapted to rotate a radial disc cam 180, a disc 182
and a second radial disc cam 184. As seen in FIG. 13, a solenoid
186 is pulsed to pull down on a link 188 which is connected to the
free end of a pivotally mounted arm 190. A spring 192 (FIG. 12)
normally urges the arm 190 upwardly to engage a stop 190a against a
ledge 194a formed in the periphery of a detent plate 194. It is
thus seen that when solenoid 186 is pulsed, the free end of arm 190
is pulled downwardly to release the detent plate 194, thereby
permitting the output shaft 178 to rotate in the counterclockwise
direction as seen in FIG. 12 through a complete revolution, as
driven by a clutch input shaft 174. At the completion of a
revolution, detent ledge 194a again encounters the stop 190a in arm
190 to inhibit further counterclockwise rotation.
As seen in FIGS. 11 and 12, radial disc cam 180 acts on a cam
follower 200 carried by a cam follower arm 202 which is secured at
its other end on a shaft 204. The other end of shaft 204 carries a
sector gear 206 which engages a spur gear 208 carried on a shaft
210 supported by a U-shaped bracket 212. The other end of shaft 210
carries an actuator arm 214 which is oriented in actuating relation
to an actuator pin 216 carried by carriage 124. Cam follower 200 is
urged against the periphery of radial disc cam 180 by a return
spring 218 acting on a return spring arm 220 secured on shaft
204.
It is thus seen that when radial disc cam 180 is rotated in the
counterclockwise direction, cam follower arm 202 is rocked
downwardly as the cam follower 200 rides up on the rise 180a. This
results in clockwise rotation of actuator arm 214 and downward
pivotal movement of carriage 124 to remove the pressure pads 132
from the vicinity of the feed roller 16. It will be recalled that
the orientation of the radial disc cam 104 in FIG. 2 at the
conclusion of a prefeed operation is such that the pressure pads
are permitted to press the leading edges of the sheet stack against
the feed roller periphery. Thus, as the prefed sheet is advanced
beyond its prefeed position, the pressure pads 132 must again be
removed from the periphery of the feed roller so as not to
interfere with the feeding of the prefed sheet. Radial disc cam 180
serves this purpose.
Returning to FIGS. 11 and 12, radial disc cam 184 acts on a cam
follower 224 carried by a cam follower arm 226 which is urged in
the counterclockwise direction by return spring 227. Cam follower
arm 226 is pivotally mounted on a shaft 228 and carries a pin 230
which is received in an elongated slot 232 formed in the free end
of detent release arm 158. This lost motion connection permits the
pawl 160 to be released from detent disc 52 by rotation of disc 108
(FIG. 2) or radial disc cam 184. Thus, to advance a prefed sheet
10a beyond its prefeed position, cam follower 224 rides up on cam
rise 184a upon rotation of radial disc cam 184 to free pawl 160
from radial wall 52b. Cam rise 184a terminates at 184b and the pawl
is permitted to assume a position in intercepting relation to
radial wall 52a as feed roller 16 is rotated in the clockwise
direction.
To drivingly rotate feed roller 16, a spur gear 240 is secured on
shaft 74 extending from the left end of the feed roller. As disc
182 is rotated through a complete revolution, gear segment teeth
182a formed in the periphery thereof engage spur gear 240, thus
imparting clockwise rotation to feed roller 16. From FIG. 1 it is
seen that such rotation advances a prefed sheet through corona
charger 26 to the nip of feed rollers 28. The length of gear
segment 182a is such that feed roller 16 is rotated through
slightly less than an angle B (FIG. 10) which, when added to angle
A, constitutes a complete revolution of the feed roller necessary
to reorient it to its angular position at the beginning of a sheet
separation and prefeed operation. This angular position is
determined by the engagement of pawl 160 with radial wall 52a of
detent disc 52.
To avoid an interference situation, gear segment 182a disengages
from spur gear 240 before the feed roller 16 has been rotated
completely through angle B. The final increment of feed roller
rotation to bring radial wall 52a of detent disc 52 into abutting
engagement with pawl 160 is induced by a column spring 244 which is
secured to a face of spur gear 208 as best seen in FIG. 11. The
free end of column spring 244 moves upwardly into engagement with a
ledge 246 formed on the periphery of detent disc 52 as cam follower
200 rides off the termination 180b of cam rise 180a formed in
radial disc cam 180 near the conclusion of a complete rotation
thereof. Column spring 244 acts against ledge 246 to rotate feed
roller 16 through a very small angle to the point where pawl 160
engages radial wall 52a, thereby finally positioning the feed
roller for the next sheet separation and prefeed operation.
It will be noted particularly from FIG. 12, that the prefed sheet
feeding rotation of the feed roller 16 occurs within the first
approximately 60.degree. of rotation of the gear segment disc 182.
As seen from FIG. 1, the sheets being separated, prefed and then
fed are significantly longer in length than the circumference of
feed roller 16, thus a complete revolution of the feed roller is
not sufficient to clear the top sheet 10a from the sheet-handling
apparatus 14. A complete feed roller revolution is sufficient
however to advance a copy sheet from its position on the sheet
stack 10 to the nip of feed rollers 28. At this point, feed rollers
28, in effect, act to pull the top sheet without further rotation
of feed roller 16 as the sheet is cleared from the sheet-handling
apparatus 14. In order to facilitate this operation, a Teflon pad
250 (FIG. 2) is embedded in each gripper ring 68 carried by feed
roller 16. The Teflon pads 250 are positioned such that they are
aligned with idler feed roller 18 when the feed roller 16 is
oriented for the beginning of a sheet separation and prefeed
operation which is also its orientation during the time that a
prefed sheet is being cleared from the sheet-handling apparatus 14
by feed rollers 28. The Teflon pads 250 thus provide a relatively
frictionless surface over which the sheets may be dragged, and thus
damage to the sheet is avoided.
An additional function of radial disc cam 184 is to actuate a
switch 252 seen in FIGS. 11 and 12. Switch 252 has a
switch-actuating arm 254 which is actuated by the raised cam
surface 184a of radial disc cam 184. This switch serves as an
interlock switch which is used to enable the actuation of solenoid
100 to initiate a sheet separation and a prefeed operation. While
the actuating arm 254 of switch 252 bears against the lower cam
surface 184c of radial disc cam 184, solenoid 100 is disabled and a
sheet separation and prefeed operation cannot be initiated.
From the foregoing description, it is seen that the operating
sequence, in summary, is as follows. Assuming a separated sheet has
been prefed to the prefeed position, preparatory to the next copy
cycle, the copier is turned on and on original document 36 is
inserted into the nip of feed rollers 32 (FIG. 1). Switch 34 is
triggered by the passage of the leading edge of the document beyond
feed rollers 32 and, as a result, solenoid 186 (FIG. 13) is
energized to engage one revolution clutch 176. The prefed sheet
10a, which is in the position shown in FIG. 9, is then fed by
rotation of feed roller 16 through the corona charger 26 and into
the nip of feed rollers 28, arriving there at the same time as does
the leading edge of document sheet 36. The feed roller 16 remains
in the orientation shown in FIGS. 1 and 7, while the sheet 10a is
cleared from the sheet handling area by the feed rollers 28. Near
the completion of the full 360.degree. rotation of radial disc cam
184, the actuating arm 254 of switch 252 rides up on the raised cam
surface 184a thereof. This occurs just after the time that the
sheet 10a has cleared the area of the sheet-handling apparatus 14
and the resulting actuation of switch 252 triggers the solenoid 100
to initiate a sheet separation and prefeed operation. Preferably,
switch 22 is connected in series with switch 252 so that solenoid
100 cannot be triggered by switch 252 if a prefed sheet 10a has not
cleared the sheet handling apparatus. As previously described, the
sheet separation and prefeed actuating means 88 then operates to
separate and advance a top sheet 10a from the sheet stack 10 and
advance it to the prefeed position shown in FIG. 9.
Switch 22 senses whether or not a sheet is in the prefeed position
preparatory the initiation of the next copy cycle. If when the
copier is turned on and switch 22 senses that no sheet is in the
prefeed position, such as would occur after the copy paper supply
has been exhausted and the stack 10 is replenished, the control
logic may be designed such that switch 22 initiates a succession of
sheet separation and prefeed operations until a sheet 10a is
successfully separated and prefed. It will be observed that
whatever the initial orientation of feed roller 16, it will be
indexed through an increment equal to angle A (FIG. 10) each time
the sheet separation and prefeed actuating mechanism 88 is
triggered by solenoid 100. During one of these indexing steps, pawl
160 engages radial wall 52a to stop the feed roller 16 at the
proper orientation for the initiation of a sheet separation and
prefeed operation. This is permitted since gear segment 110 will
slip on ring 150 after feed roller rotation has been inhibited by
pawl 160. With the next pulsing of solenoid 100, a top sheet 10a is
separated and prefed, whereupon switch 22 is tripped and the copier
is then prepared for a normal copy cycle.
It will thus be seen that the objects set forth above, among those
made apparent from the preceding description, are efficiently
attained and, since certain changes may be made in the above
construction without departing from the scope of the invention, it
is intended that all matter contained in the above description or
shown in the accompanying drawings shall be interpreted as
illustrative and not in a limiting sense.
* * * * *