U.S. patent number 3,698,805 [Application Number 05/191,304] was granted by the patent office on 1972-10-17 for control apparatus for electrophotographic apparatus.
This patent grant is currently assigned to Eastman Kodak Company. Invention is credited to Frank L. Guyette, Lionel R. Hickey.
United States Patent |
3,698,805 |
Hickey , et al. |
October 17, 1972 |
CONTROL APPARATUS FOR ELECTROPHOTOGRAPHIC APPARATUS
Abstract
An electrophotographic copying apparatus having an
electrophotographic web movable along an endless path relative to a
plurality of actuable work stations disposed along the path and
wherein each of the work stations is operative when actuated to
perform a work operation on the web. The apparatus includes a
sequencer for sequentially producing, (a) a plurality of control
signals, each such control signals for causing particular ones of
the electrophotographic stations to perform work operations on the
web in timed relation to web movement respectively, and (b) a count
signal each time a selected station performs its operation. The
apparatus further includes counter means responsive to each count
signal and having a state which manifests the cumulative total
number of count signals, and means responsive to a particular state
of the counter means corresponding to a predetermined cumulative
total number of count signals to prevent the further actuation of
each work station after each station has performed a predetermined
number of work operations.
Inventors: |
Hickey; Lionel R. (Webster,
NY), Guyette; Frank L. (Rochester, NY) |
Assignee: |
Eastman Kodak Company
(Rochester, NY)
|
Family
ID: |
22704948 |
Appl.
No.: |
05/191,304 |
Filed: |
October 21, 1971 |
Current U.S.
Class: |
399/76 |
Current CPC
Class: |
G05B
19/063 (20130101); G03G 21/145 (20130101) |
Current International
Class: |
G05B
19/06 (20060101); G03G 21/14 (20060101); G05B
19/04 (20060101); G03g 015/00 () |
Field of
Search: |
;355/14,16,17,3
;328/72,75 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Matthews; Samuel S.
Assistant Examiner: Moses; Richard L.
Claims
We claim:
1. In electrophotographic apparatus having an
electro-photosensitive web, means for moving the
electrophotosensitive web along an endless path relative to a
plurality of actuable work stations wherein each of the work
stations is operative when actuated to perform a work operation on
the web, the combination comprising:
a. a plurality of actuable work station actuating means;
b. means for sequentially actuating particular ones of the work
station actuating means in timed relation to movement of the web
past predetermined positions along the path for sequentially
actuating corresponding work stations to cause them to perform work
operations on the web respectively, and producing at least one
signal indicative of each time at least one particular work station
has performed a work operation on the web;
c. counter means responsive to said signals and having a state
representative of the total cumulative number of said signals;
and
d. means responsive to a particular state of said counter means
corresponding to a selected cumulative number of said signals for
preventing actuation of each of said work station actuating means
after its corresponding work station has performed a predetermined
number of work operations.
2. In electrophotographic apparatus having means for repetitively
moving an electrophotosensitive web along a first endless path
relative to a plurality of actuable work stations, wherein each
work station is operative when actuated to perform a work operation
on the web, the combination comprising:
a. means defining a second predetermined path;
b. a plurality of signal actuable work station actuating means,
each of said actuating means being disposed at a predetermined
position along the second predetermined path;
c. means movable along said second predetermined path for
sequentially actuating particular ones of said plurality of work
station actuating means in timed relation to movement of the web
past predetermined positions along the first path for sequentially
actuating the work stations to perform work operations on the web,
respectively;
d. counter means responsive to said count signals and having a
state representative of the total cumulative number of count
signals; and
e. means responsive to a particular state of said counter means
corresponding to a selected cumulative number of said count signals
for sequentially preventing actuation of each said work station
after it has performed a predetermined number of work
operations.
3. The invention as set forth in claim 2 wherein said sequential
actuating means includes an element movable along the second
predetermined path, a source of energy on said element, and wherein
said plurality of actuable work station actuating means comprises a
plurality of energy sensing means disposed at predetermined
positions on the second path and responsive to said energy source
upon movement of said element along said second path to actuate
particular ones of the work stations to perform a work operation on
the web, respectively.
4. The apparatus as set forth in claim 2 wherein said sequential
actuating means includes drive means effective in a first condition
for moving the web along the endless path relative to the work
stations and in a second condition for stopping movement of the web
and wherein said selected counter state responsive means is
responsive to said selected cumulative number to be effective to
cause said drive means to be in said second condition.
5. In electrophotographic apparatus including a photoconductive
member movable along an endless path past a plurality of
electrophotographic stations to make one or more toner images from
an original, said apparatus including:
means defining said endless path;
drive means for moving the photoconductive member along said
endless path through said electrophotographic stations;
Sequencer means responsive to movement of the photoconductive
member to provide (a) output control signals sequentially to
control said electrophotographic stations and (b) at least one
count signal indicating that a print has been made;
circuit means to enable said drive means and said sequencer
means;
means to energize said circuit means to initiate operation of said
apparatus;
counter means responsive to said count signals to manifest a
cumulative total number of count signals; and
means adjustable to be responsive to a selected cumulative
predetermined number of count signals to de-energize said circuit
means and disable said drive means and said sequencer means in a
timed sequence to permit the predetermined number of toner images
to be made from the original.
6. The invention as set forth in claim 5 wherein said sequencer
means includes a device movable along a second predetermined path
by said drive means to produce said output control signals.
7. Apparatus, as claimed in claim 6, wherein one of said
electrophotographic stations is a transfer station for transferring
the toner images sequentially to receiver sheets fed through said
transfer station, said apparatus further including:
means for feeding the receiver sheets through said transfer station
to receive the toner images; and
a fusing station spaced from said endless path including feed means
connected to said drive means for feeding the image-bearing
receivers through the fusing station to fuse the respective images
thereto;
said circuit means including:
a clutch for connecting said drive means to the photoconductive
member; and
means to disable said clutch in response to an output signal from
said sequencer means to stop the photoconductive member and to
sequentially disable said drive means after a predetermined length
of time sufficient to feed the last image-bearing receiver through
said fusing station.
8. Apparatus, as claimed in claim 7 wherein one of said plurality
of electrophotographic stations is a charging station and said one
of said control signals for turning on said charging station is
said count signal.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
Reference is made to commonly assigned U. S. Pat. application Ser.
No. 19,644, now abandoned, entitled, MAGNETICALLY CONTROLLED
PROGRAMMER and commonly assigned U. S. Pat. application Ser. No.
19,999, entitled, MACHINE PROGRAMMER both filed Mar. 16, 1970 and
commonly assigned U. S. Pat. application Ser. No. 834,695, now U.
S. Pat. No. 3,619,050 entitled, WEB HANDLING APPARATUS AND
CARTRIDGE AND WEB filed June 19, 1969, the disclosures of which are
incorporated in their entirety herein.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to the fields of electrophotography and web
handling. More specifically, this invention relates to
electrophotographic apparatus having electrophotosensitive members
in the form of an endless web and including means for facilitating
the supply, removal and/or replacement of such
electrophotosensitive webs.
2. Description of the Prior Art
In a common form of electrophotography, an electrical image of an
information medium such as a document is formed in an
electrophotosensitive member in response to imagewise actinic
radiation reflected from the medium. The electrophotosensitive
member includes a photoconductive layer with a conductive backing.
In accordance with this known form of electrophotography, such an
electrophotosensitive member is transported relative to a plurality
of work stations, each of which when actuated performs a work
operation. Such stations include a charging station at which a
uniform charge is placed on the photoconductive layer, an exposure
station at which the charged photoconductive layer is imagewise
exposed to actinic radiation reflected from the medium to create an
electrostatic image of the medium in the photoconductive layer, a
developing station at which the electrostatic image is contacted
with finely divided charged toner particles that adhere to the
photoconductive layer in a configuration defined by the
electrostatic image, a transfer station at which toner particles
are transferred in the image configuration to a receiving surface,
and a cleaning station at which residual toner is removed from the
photoconductive layer so that it can be reused. In certain known
modifications of this same system one or more of these stations are
eliminated.
In applications in which the electrophotosensitive member is
continually reused, the electrophotosensitive member can be
constructed in the form of a drum, a plate or an endless web. The
endless web configuration has certain advantages over drums and
plates. Among these advantages is flexibility of machine design for
such a web can be disposed in flat configuration at one location in
the apparatus to facilitate some operations such as, e.g., exposure
and in a curved configuration at other locations to facilitate such
other operations as the separation of a transfer sheet
therefrom.
However, some of the advantages of endless web type
electrophotosensitive apparatus pointed out above may be offset by
the difficulty of providing efficient apparatus for properly
actuating work stations and controlling the number of copies to be
made.
SUMMARY OF THE INVENTION
It is an object of this invention to provide for use in endless web
type electrophotographic copy apparatus, improved means for
controlling the actuation of work stations in such copy apparatus
and coordinating such actuation with the controlling of the number
of copies to be made.
In accordance with a disclosed embodiment of this invention,
apparatus includes an electrophotographic web movable relative to a
plurality of actuable work stations along an endless path wherein a
work operation is performed at each station when it is actuated.
The apparatus includes means for moving the web along the endless
path relative to the work stations, means for (a) sequentially
producing a plurality of output control signals, each of said
control signals being adapted to cause the actuating of particular
ones of the work stations to perform work operations on the web
respectively, and (b) a count signal each time a particular work
station has performed a work operation on the web. The apparatus
further includes a counter responsive to the count signals and
having a state which manifests the cumulative total number of count
signals, and means responsive to a state of the counter means
corresponding to a selected predetermined cumulative total number
of count signals to cause the signal producing means to prevent
further actuation of each station of the apparatus after each work
station has performed a predetermined number of work
operations.
More particularly, the invention includes an electrophotographic
apparatus wherein the count signal is provided by the control
signal for turning on the charging station and the apparatus
includes a transfer station and a fusing station through which a
receiver sheet is fed to transfer a toner image from an endless
electrophotographic web to the receiver sheet which toner image is
then fused in the fusing station. After a predetermined number of
copies have been made, means coupled to the counter causes the
apparatus to shut down sequentially so that the photoconductive
member first discontinues operation while the fusing station and
the drive means therefore continues operating until the final print
has been discharged from the fusing station after which the entire
apparatus is shut down.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram showing the arrangement of apparatus for
actuating various work stations in web type electrophotographic
apparatus; and
FIG. 2 is a block diagram showing the arrangement of apparatus for
controlling web replacement and various machine operations during
web replacement in the electrophotographic apparatus shown in FIG.
1.
The symbols for the logic components shown in the drawings are in
accordance with American Standard Graphical Symbols for Logical
Diagrams (ASA&32.14-1962).
DESCRIPTION OF THE PREFERRED EMBODIMENT
In accordance with this invention, control logic, as illustrated in
FIG. 1, is provided for an electrophotographic device E that
includes an electrophotosensitive web or belt 2, which comprises at
least a photoconductive surface on a conductive backing. The web
has a leading end attached to a tow bar 4 by which it is moved
along an endless path past rollers 6, 8, 10, 12 and 14
respectively, as shown, and is attached to a trailing end by a
plurality of studs 16 as disclosed in commonly assigned copending
U. S. application Ser. No. 834,695, now U.S. Pat. No. 3,619,050,
entitled, WEB HANDLING APPARATUS AND CARTRIDGE AND WEB USABLE
THEREWITH to Thaddeus Swanke, filed June 19, 1969. Belt 2 is driven
through a drive train which includes a main drive motor 18, an
electric clutch 20, a brake 22 and a second clutch 24. Clutch 24
includes a motor and is movable to either of two driving positions.
Whenenergized, it is moved to a first position to serve as a
driving connection between main drive motor 18 and photoconductive
belt 2. When de-energized, it moves under the urging of a spring
(not shown) to a second position to serve as a driving connection
between thread-unthread motor 25, as discussed below in connection
with FIG. 2.
The general operation of the device E will now be described. As the
photoconductive belt 2 is driven, a portion thereof moving past a
charging device 26, such as a corona charger, receives a generally
uniform electrostatic charge. Thereafter, the charged portion is
exposed to a pattern of actinic radiation at an exposure station 28
whereat the image of an original 30 is illuminated by a plurality
of high intensity light sources 32 and is projected upon the
opening of shutter 38, as described below. The electrostatic charge
in the exposed areas is dissipated leaving an electrostatic latent
image. This latent image is developed by toner particles at a
developing station 40. The toner particles may have a charge
opposite that of the electrostatic image are attracted thereto to
form a toner image. The toner image is advanced by the belt along
the endless path to the vicinity of transfer charger station 42 so
that it arrives at the transfer station in synchronism with the
arrival of a receiver sheet fed from a paper supply 44 which is fed
by means of a sheet feeder. The sheet feeder includes a vacuum
finger 46, 48 and 50 which delivers a receiver sheet to a pair of
opposed feed rollers so that the receiver sheet is brought into
face-to-face contact with the toner image at transfer station 42
whereupon the toner image is transferred from the photoconductive
belt to a receiver sheet. Although sheet feeders may take various
forms known in the art, the sheet feeder disclosed in commonly
assigned copending application, U. S. Ser. No. 23,705, now
abandoned entitled, PAPER FEED AND EXPOSURE SYNCHRONIZER to Jorgen
Reesen, filed Mar. 30, 1970 is especially suitable for use with the
device E. The receiver sheet is separated from the photoconductive
belt at small radius roller 12 and is moved through a fusing
station 52 by a transport mechanism 53 where the toner image
thereon is fused to the receiver to make a permanent copy which
then is fed to a suitable receiving means (not shown). Any residual
toner particles remaining on the photoconductive belt 2 are removed
at cleaning station 54 and the remaining electrostatic charge on
the belt is discharged by erase lamp 56 after which the cycle can
be repeated. It will be understood that a plurality of
electrostatic and toner images may be placed sequentially on
successive portions of the web as it moves along its endless path
so that each of the above-described work operations performed at
each work station occurs simultaneously and in proper sequence on
different portions of the web.
Advantageously, the sequential operation of the various stations
are controlled by a sequencer or shift register S. The sequencer S
may take various forms known in the art such as an electronic shift
register wherein the input to each stage is provided by the output
of a previous stage, with data being transferred during application
of a pulse-type shift command signal. Alternatively, and as shown,
a mechanical sequencer may be provided which performs the same
machine control functions as would a shift register. The sequencer
S disclosed in commonly assigned copending application, U. S. Ser.
No. 19,644, now abandoned entitled, MAGNETICALLY CONTROLLED MACHINE
PROGRAMMER, filed Mar. 16, 1970 is especially suitable for use with
the device E. The shift register S comprises a rotatable cylinder
which is divided into a plurality of light-tight sectors 58, 60,
62, 64 and 66. As the shift register is rotated, an initiator coil
68 enables a signal circuit (not shown) in each sector which
includes an output signal lamp, such as lamps 70, 71, 72, 73 and
74, respectively, in sector 58 which shines through slots 75, 76,
77, 78 and 79, respectively in the periphery of the respective
sectors to sequentially energize a plurality of photocells spaced
around a stationary sleeve 80 which has a slot 82 adjacent each
photocell to permit passage of light therethrough.
For each copy that is to be made, a sector is illuminated by
initiator coil 68 which sector then provides signals to cause
various electrophotographic operations to be performed on
corresponding segments of the photoconductive belt 2. At the end of
the cycle, the signal circuit for the sector is disabled as by a
permanent magnet 92 which opens a read switch (not shown) as
discussed more fully in my above-mentioned copending
application.
To operate the apparatus the operator first closes main power
supply switch 94 which provides one input to AND gate 96. It will
be understood that by closing this switch power is also supplied to
other portions of the apparatus. For example, power can be supplied
to preheat the fusing station 52 so that it will be at the proper
temperature when the first print is made. Also, power is being
provided to the various motors and controls which will be energized
at appropriate times during operation of the machine by the logic
circuit to be described. However, the means for supplying power to
these portions of the apparatus have been omitted from both FIGS. 1
and 2 for clarity of illustration. A second input to AND gate 96 is
provided by input line 98 from circuitry connected to various
interlocks (not shown) which sense that all doors and compartments
of the apparatus are closed before it can be energized and that
developing station 40 and cleaning station 54 are in their raised
position. A third inverted input is provided when normally open
threading cycle switch 100, has not been closed to furnish a signal
from potential source 101. The threading mode of operation will be
described below in connection with FIG. 2. A fourth inverted input
indicates that there is no paper jam, as described more fully
below. A fifth input signal is supplied through switch 102 from
potential source 104 at paper supply station 44 to indicate that
the paper supply is adequate for operation of the apparatus. A
sixth input signal indicates that a photoconductive magazine
containing a web is in position in a magazine receiving chamber
258. A seventh input signal to AND gate 96 is provided from
developing station 40 indicating that a proper supply of toner is
present. An eighth input signal to AND gate 96 is provided from
timer 110 as long as the photoconductor has not been operated
beyond its useful like, as more fully discussed below. It will be
understood that other inputs can be provided to AND gate 96 to
indicate that other operational parts of the structure are in
proper operating position or condition. The final input to AND gate
96 which has been illustrated, is provided by OR gate 112. OR gate
112 has two inputs. The first is momentarily energized when a print
button 118 is depressed which couples the OR gate 112 to a source
of potential 120. When the button 118 is depressed, the AND gate 96
is energized and provides an input signal to an AND gate 122. A
second normally energized signal is provided to the AND gate 122 so
that when the button 118 is released, the AND gate 122 provides the
second high level signal to the OR gate 112 which causes the AND
gate 96 to remain energized. The AND gate 96 will only be
de-energized when the AND gate 122 is inhibited.
To make a print the operator first selects a predetermined number
of prints desired in a storage device 113a which provides a set of
digital signals to the coincidence detector 113b which also
receives inputs from the various stages of a digital counter 114.
When a coincidence condition is detected, (viz. at the time, the
state of the counter manifests that the cumulative total number has
reached such a predetermined number) the coincidence detector
switches its signal to the AND gate 122 and the counter 114 to a
low level. The AND gate 122 is thus de-energized which causes the
AND gate 96 to turn off. The fall edge of the signal to the counter
114 causes it to reset to a "zero" storage condition.
The output from AND gate 96 also enables initiator coil 68 to light
successive sectors of shift register S as each one moves past the
initiator coil upon rotation of the shift register as described in
my above-mentioned copending application. In addition, the output
signal from AND gate 96 enables OR gate 123.
The output signal from OR gate 123 performs several functions. It
engages clutch 20, releases brake 22 and enables OR gate 124 to
move clutch 24 into a position in which it is in driving engagement
with main drive motor 18. In addition, the same signal provides an
input signal to timer 110, energizes erase lamp 56 and energizes
solenoid 121 to open shutter 38. The timer will run whenever the
apparatus is operating. When the time period for the useful life of
photoconductive belt 2 has expired, the output signal from timer
110 is terminated thereby disabling the output of the AND gate 96
which causes a shutdown of the operation of the machine, as
described hereinafter. The timer also provides a signal to a
control panel (not shown) to tell the operator that the
photoconductive web is to be replaced.
The output from OR gate 123 also activates vacuum supply 125 for
vacuum fingers 46 and enables AND gate 126 which will keep OR gate
123 in an enabled state for a predetermined time after AND gate 96
is de-energized during a normal shutdown of the apparatus after the
desired number of copies have been made as will be discussed more
fully hereinafter. The output from OR gate 123 will also enable OR
gate 127 whose output enables lamps 128 and 129 of synchronizer 130
and OR gate 131 which in turn enables main drive motor 18. This
synchronizer is mechanically coupled to the fingers 46 of the sheet
feeder and the sequencer 130 is disclosed in above-mentioned
commonly assigned U. S. application Ser. No. 23,705. OR gate 127
enables OR gate 131 which in turn enables main drive motor 18 to
drive photoconductive web 2 along its endless path and cause shift
register S and synchronizer 130 to be rotated in the directions
indicated.
As shift register S begins to turn the signal circuit of the first
sector, such as sector 58 is enabled by initiator coil 68 so that
lamp 70 is illuminated. When it reaches the position where slot 75
is aligned with slot 82 adjacent photocell 132, the photocell will
be illuminated to provide a signal to set flip-flop 134 which now
provides a signal from its "one" output to energize a high voltage
supply 134a which in turn energizes a corona charger 26 and thereby
place a generally uniform charge on a segment of photoconductive
belt 2. The signal from photocell 132 also provides a count signal
to counter 114 to permit it to change state. As the shift register
continues to turn in synchronism with the movement of the charged
segment of belt 2, the light from the lamp will energize photocell
136 when slot 75 is aligned with slot 82 adjacent photocell 136 to
clear flip-flop 134 and hence de-energized the supply 134a and turn
off charger 26 and to also set flip-flop 138 which then provides a
signal from its "one" output to one input of AND gate 140 to arm
exposure station 28. The second input signal to AND gate 140 is
provided by synchronizer 130 when slot 142 thereof is positioned so
that light 128 illuminates photocell 144. This occurs when vacuum
fingers 46 are in proper position to feed a receiver sheet in
proper timed relation to the segment of belt 2 from which a toner
image is to be transferred. The signal from photocell 144 enables
AND gate 140 which enables single shot 146 to provide a pulse
signal to a high voltage power supply say, for example, in the
order of 3KV for a predetermined time duration illuminating the
flashlamps 32. In this manner charged photoconductive belt 2 is
exposed to an image of original 30 thereby dissipating the charge
in the exposed areas to form an electrostatic latent image thereon.
It will be understood that the power supply 146a may include means
for varying the exposure time as desired.
Further rotation of shift register S illuminates photocell 150 to
provide a signal to reset flip-flop 138 so that AND gate 140 can
later be armed for exposure of the next charged portion of
photoconductive belt 2. Next, photocell 152 is illuminated to
provide a signal to vacuum control circuit 154 which may be
embodied by a flip-flop adapted to energize a valve (not shown) to
supply a vacuum from vacuum supply 125 to vacuum fingers 46.
The enabled sector of shift register S will illuminate photocell
156 next to provide a signal to turn on automatic bias control
circuit 158 to adjust the potential on a development electrode (not
shown) which forms a part of developer station 40. Next, photocell
160 will be illuminated to provide a signal to turn on transfer
charger 42 and to clear flip-flop 162, whose function is explained
below. Photocell 164 is then illuminated to turn off bias control
circuit 158 as a developed toner image leaves developing station
40.
At the appropriate time, slot 142 of synchronizer 130 will become
aligned with photocell 165 so that it is illuminated by light 129.
This will cause the photocell to provide a signal to turn off
vacuum control circuit 154 when a copy sheet has been fed between
feed rollers 48 and 50.
Subsequently, the synchronizer S causes illumination of photocell
166 by the enabled sector of shift register S. The photocell 166
produces an input signal to the set side of a flip-flop 162 which
provides an output signal to one input of AND gate 168 to arm a
circuit for shutting down the machine if no additional prints are
to be made, i.e., if no more sectors are illuminated. If another
sector is illuminated, photocell 160 will again be energized to
clear flip-flop 162 and thereby terminate the input signal to AND
gate 168. Finally, photocell 170 is illuminated, but only after the
next sector has passed by photocell 160, to provide a second and
final input signal to AND gate 168. If the next sector is enabled
flip-flop 162 has been cleared, so AND gate 168 will not be
enabled. On the other hand, if the next sector is disabled, as
described in the above-mentioned U. S. Pat. application, Ser. No.
19,644, flip-flop 162 is still set and AND gate 168 is enabled to
shut down the apparatus, as described below.
The signal from photocell 170 turns off transfer charger 42 and
provides one input to a paper jam time delay circuit 172 which has
another input connected to a paper sensor 174. If a receiving sheet
does not come out of fusing station 52 within the required time so
that it is sensed by sensor 174, time delay circuit 172 provides a
signal which disables AND gate 96 to shut down operation of the
apparatus immediately. Any suitable time delay circuit may be used,
such as one in which a capacitor (not shown) is charged to a
predetermined level over a given time period after which the signal
is generated. The signal from time delay circuit 172 will also
disable AND gates 126 and 180 which in turn disable OR gates 123
and 127, respectively, and thereby shut down all operations of the
apparatus. After the paper jam is cleared, the operator closes
print button 118 again and operation resumes.
Assuming no paper jam occurs, the lighted sector will be disabled
or turned off by permanent magnet 92 which will open a reed switch
in the output circuit of the sector (not shown) as described more
fully in my copending U. S. application Ser. No. 19,644. The sector
can be enabled again by initiator coil 68 and the cycle repeated so
long as counter 114 has not counted down to zero.
When a signal from photocell 132, representing the last print to be
made, occurs the detector 113b reaches coincidence and terminates
the signal from the "one" output thereof thereby disabling AND gate
122 and OR gate 112 which in turn disables AND gate 96. The
disablement of AND gate 96 disables initiator coil 68 so that no
more sectors are illuminated and it also terminates one input
signal to OR gate 123 but OR gate 123 remains enabled by AND gate
126 and the apparatus continues to run, printing out the remaining
images which are in various stages of formation at different
sections of belt 2. However, when photocell 170 is illuminated by
the last lighted sector, AND gate 168 is enabled since no lighted
sectors remain to clear flip-flop 162. The resulting output signal
from AND gate 168 disables AND gate 126, which disables OR gate 123
so that clutch 20 is disengaged, brake 22 is engaged, OR gate 124
is disabled to disengage clutch 24 and vacuum supply 125 is turned
off. This stops operation of endless belt 20, developing station
40, cleaning station 54 and shift register S which will coast just
far enough so that the last lighted sector will be turned off by
permanent magnet 92. However, main drive motor 18 continues running
for a predetermined time, so that fusing station 52 and transport
mechanism 53 operate until the last print exists therefrom. This
time period is determined by time delay circuit 178 which is
activated by a signal from photocell 170 to keep AND gate 180 and
OR gate 127 enabled for the predetermined period.
When photoconductive web 2 is to be replaced, the used web may be
removed from the apparatus and a new web threaded thereon by the
automatic threading apparatus and logic circuitry shown in FIG. 2.
To begin the rewind operation, the operator closes normally open
switch 100 which provides an input from power source 101 to AND
gate 194 whose first input is provided from main power switch 94
(see FIG. 1). AND gate 194 establishes an output signal and
provides it to counter 196, to one input of AND gate 198, and to an
enabling circuit 200 which energizes lamp 74 of sector 66 of
sequencer S. No other sectors are enabled during the unthreading or
threading operation. AND gate 198 is now enabled and energizes a
developer station motor 202 which moves developing station 40 away
from belt 2 from the position shown so as to close normally open
switch 204 which provides a signal from potential source 206 to one
input of AND gate 208 and to one input of AND gate 210. This signal
enables AND gate 210 which then provides an output signal to OR
gate 124 to enable it. OR gate 124 energizes clutch 24 which moves
to a position wherein it connects the roller 8 to main drive motor
18. The output signal from AND gate 210 also provides an input
signal to OR gate 131 which energizes drive motor 18. The motor 18
is now coupled to the photoconductive web 2 and causes it to be
moved at relatively high speed in a generally counterclockwise
direction of travel as indicated by arrow 212 and sequencer S is
rotated in a clockwise direction as indicated by arrow 213. The
signal from potential source 206 also provides an input which is
inverted, to AND gate 198 when the developing station is in a
position spaced from photoconductive web 2 to disable AND gate 198
and hence motor 202.
During a predetermined number of cycles as determined by counter
196 any residual toner powder remaining on photoconductive web 2 is
removed by cleaning station 54. Each time web 2 makes a complete
revolution, sequencer S also makes a complete revolution and
provides an output signal from lighted sector 66 to photocell 214
which provides a countdown pulse to counter 196, and also an input
pulse to one input of AND gate 216. The counter block 196 will also
be understood to include an AND gate which is coupled to selected
output lines of the stages of the counter so that when
photoconductive web has made a desired number of revolutions, such
as 5 or 6, as preset by the AND gate, the AND gate provides an
output signal which is delivered to AND gate 216. AND gate 216 is
now enabled and provides an output signal to one input terminal of
AND gate 218 and to the second inverted input terminal of AND gate
210. AND gate 210 is now disabled and de-energizes OR gate 131,
which in turn disables drive motor 18 stopping movement of
photoconductive web 2. The disabling of AND gate 210 also disables
OR gate 124 and deenergizes clutch 24. Meanwhile, AND gate 218 has
been enabled to cause cleaning station positioning motor 220 to
lower cleaning station 54 from the position shown to the position
where it closes normally open switch 222 to provide a signal from
potential source 224 to an inverted second input of AND gate 218 to
disable AND gate 218 and stop motor 220. The signal from potential
source 222 also provides the signal to the second and final input
of AND gate 208 which is enabled to move clutch 24 to a position to
bring thread-unthread motor 25 into driving engagement with
photoconductive web 2 and to set flip-flop 209 for a purpose to be
described. Furthermore, the signal from potential source 224 is
provided to one input of AND gate 225 and to one input of AND gate
226 which is enabled and in turn enables motor 25 to drive
photoconductive web 2 in the unthread direction as indicated by
dashed arrow 228. Photoconductive web 2 is driven at a much slower
speed by thread-unthread motor 25 than by main drive motor 18
during which various functions of the unthreading and threading
cycles are initiated by lighted sector 66 of sequencer S.
During movement in the unthreading direction of arrow 228,
sequencer S rotates in the direction of dashed arrow 229 so that
lighted sector 66 moves from a position wherein light 74 shines
through a slot 82 to illuminate photocell 214 to a position in
which light passes through a slot 82 to illuminate photocell 230
and provide a second input signal to AND gate 225 which causes
guide roller drive 232 to move guide rollers 234 from a retracted
position to an extended position adjacent web 2 to close switch 236
which causes a signal to be provided from potential source 238 to a
third inverted input to AND gate 225 to disable the AND gate and
stop guide roller drive 232. This same signal, provided by
potential source 238, is also applied to one input of AND gate 239
which enables the AND gate to in turn enable OR gate 240 which
causes photoconductor tension motor 241 to be energized to move
roller 6 to the right, as viewed in FIG. 2, to release tension on
photoconductive web 2 so that lugs 16 can be unhooked from tow bar
4. When roller 6 has been moved to a position in which the tension
is released, normally open switch 242 provides a signal from
potential source 244 to an inverted input to AND gate 239 to
disable it and to disable OR gate 240 and tension motor 241. This
same signal from potential source 244 is provided to an inverted
input to AND gate 246, to an input of AND gate 248, flip-flop 249
which provides an input to AND gate 250, flip-flop 251 which
provides an input to AND gate 252, AND gate 254 to an inverted
input of AND gate 255 and to clear flip-flop 279 as described.
The signal to the input of AND gate 248 enables this AND gate to
cause takeup motor 256 to be energized so that photoconductive web
2 is fed into magazine 258 in a manner described more specifically
in above-mentioned commonly assigned U. S. Ser. No. 834,695, filed
June 19, 1969. Thus, as thread and unthread motor 25 continues to
move the belt in the unthread direction of arrow 228, takeup motor
256 continues to wind the end of web 2, which has been unhooked
from lugs 16, onto magazine 258. When illuminated sector 66 reaches
a position wherein light 74 shines through slot 82 to illuminate
photocell 136, a signal is provided to a second input of AND gate
252 which is now enabled thereby causing OR gate 260 to apply a
potential to tension motor 241 to run it in the reverse direction
to move roller 6 toward the left, as viewed in FIG. 2 to restore
tension and close normally open switch 262 to provide a signal from
potential source 264 to an inverted input of both AND gates 250 and
252 and to clear flip-flops 249 and 251. The signal to AND gate 252
disables this AND gate and also disables OR gate 260 so that
tension motor 241 is de-energized. The signal from potential source
264 is also provided to one input of AND gate 266. The
photoconductive web 2 continues to be wound onto magazine 258 until
sector 66 of the sequencer reaches a position wherein photocell 268
is illuminated and provides a second input signal to AND gate 266
which is enabled and in turn enables OR gate 270 which causes guide
roller drive 232 to move guide rollers 234 from the extended
position in which switch 236 was closed toward a retracted position
so that the guide rollers close an intermediate position switch 272
to provide a signal from potential source 238 to an inverted input
to AND gate 268 thereby disabling that AND gate 266 and OR gate 270
to de-energized guide roller drive 232. In addition, the signal
from potential source 238 is applied to the set input of a
flip-flop 273 which changes state and applies a signal to an
inverted input to AND gates 226 and 248 respectively which are then
disabled and de-energize thread-unthread motor 25 and takeup motor
256, respectively. At this point, the entire apparatus is disabled
and used photoconductive web 2 is completely stored within magazine
258 for removal by the operator.
The operator now opens a compartment door in the apparatus and
removes the magazine containing the old photoconductive web and
replaces it with a magazine containing a new photoconductive web in
a manner more fully described in the above-identified copending
application. When a new magazine has been placed in the machine and
the door closed, the operator closes normally open switch 274 which
provides a signal from potential source 276 to AND gate 278 which
is then enabled causing thread-unthread motor 25 to be driven in
the thread direction so that the end of the new photoconductive web
is attached to the tow bar and pulled along the path in the
direction of arrow 212. Of course, sequencer S will be rotated in a
clockwise direction as indicated by arrow 213 during this portion
of the threading operation. Since the sequencer had previously
stopped in a position in which photocell 268 was energized, and
provided a signal which set flip-flop 279 which in turn provided a
first input to an AND gate 280, when the AND gate 28 receives a
second and final input from the output of AND gate 78 it provides a
signal to normally open switch 282 which is closed when the
photoconductive web reaches the position of the switch to provide a
signal indicating that the new photoconductive web 2 is being
properly fed along its endless path. This latter signal is provided
to one input of AND gate 246 which is enabled and in turn enables
OR gate 240 and drives photoconductive tension motor 241 in a
direction to release tension by moving roller 6 to the right as
viewed in FIG. 2. When tension roller 6 reaches a position wherein
it closes tension-release switch 242, a signal will be provided
from potential source 244 to an inverted input to AND gate 246
thereby disabling the AND gate 246 and OR gate 240 to de-energize
motor 241. This same signal from potential source 244 also clears
flip-flop 279 and sets flip-flops 249 and 251.
Photoconductive web 2 continues to be threaded around its endless
path until tow bar 4 is overlapped by the trailing end of the web
which is now completely removed from magazine 258 and is engaged
with lugs 16. At this point, illuminated sector 66 reaches a
position to illuminate photocell 284 which provides a signal to a
second and final input to AND gate 254 whose first input is
provided from potential source 244 by switch 242. The output signal
from AND gate 254 to an inverted input to AND gate 278 disables the
AND gate and de-energizes motor 25.
The signal from photocell 284 also provides an input to AND gate
250 whose second input is provided by flip-flop 249 thereby
enabling AND gate 250 and also enabling OR gate 260 to energize
tension motor 241 to move tension roller 6 to the left as viewed in
FIG. 2 to interlock the overlapping end of new photoconductive web
2 with lugs 16. This movement continues until tension restoring
switch 262 is closed, thereby providing a signal from potential
source 264 to an inverted input to AND gate 250 thereby disabling
it as well as OR gate 260 to de-energize motor 241. This signal
from potential source 264 also clears flip-flop 249 and 251.
The signal from photocell 284 as well as the signal from potential
source 264 are provided to first and second inputs to AND gate 286
which is enabled thereby enabling OR gate 270 to cause guide roller
drive 232 to move guide rollers 234 from their intermediate
position to a retracted position whereupon switch 288 is closed to
provide a signal from potential source 238 to an inverted input of
AND gate 286 thereby disabling the AND gate and also disabling OR
gate 270 to de-energize guide roller drive 232.
Simultaneously, AND gate 290 is enabled by receiving input signals
from photocell 284 and from potential source 264 thereby causing
cleaning station positioning motor 220 to drive the cleaning
station from a lowered position to the raised position shown until
switch 201 is closed whereupon a signal is provided from a
potential source 199 to an inverted input of AND gate 290 disabling
the AND gate and de-energizing motor 220. The same signal clears
flip-flop 273 and also provides a signal to the second input of AND
gate 292, which receives an input signal from previously set
flip-flop 209, and therefore is now enabled. The output signal from
AND gate 292 enables OR gate 131 to cause main drive motor 18 to be
driven through clutch 24 which has been moved to its main drive
position by the same output signal from AND gate 292 which also
enables OR gate 124. Thus, photoconductive web 2 and sequencer S
continue moving in the same direction they have been moving but now
they are driven at a higher speed by main drive motor 18 rather
than at a slower speed by motor 25. When lighted sector 66
illuminates photocell 170, the output signal from the photocell
provides a signal to an inverted input to AND gate 292 thereby
disabling the AND gate and disabling OR gate 131 to de-energize
main drive motor 18 and stop movement of photoconductive web 2. In
addition, the signal from photocell 170 provides an input signal to
single shot 294 which provides an output signal to one input of AND
gate 255 for a sufficient length of time to cause motor 202 to move
developing station 40 from a lowered position to the raised
position shown in FIG. 2. Upon reaching the raised position, a
normally open switch 298 is closed to provide a signal from
potential source 300 to clear flip-flop 209 and to an inverted
input to AND gate 255 thereby disabling the AND gate and
de-energizing motor 202. In addition, this signal resets counter
196 and provides a signal to one input of AND gate 302 whose second
input is provided by single shot 294 thereby enabling AND gate 302
which provides an inverted signal to a third input to AND gate 194
thereby disabling the AND gate and terminating the signal to
circuit 200 to disable sector 66. At this point, the threading
operation has been completed.
From the foregoing, the advantages of this invention are readily
apparent. An apparatus has been provided wherein a count signal to
an arbitrary number counter is provided from one of the signals for
controlling the apparatus from a sequencer. In addition, the
apparatus shuts down in a sequential manner so that the
photoconductive member stops movement as soon as the last print is
made whereas the fusing station continues operating until a
receiver sheet bearing the last toner image is transferred
therethrough.
The invention has been described in detail with reference to a
preferred embodiment thereof, but it will be understood that
variations and modifications can be effected within the spirit and
scope of the invention.
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