U.S. patent number 3,880,516 [Application Number 05/444,997] was granted by the patent office on 1975-04-29 for diagnostic circuit board.
This patent grant is currently assigned to Xerox Corporation. Invention is credited to Kenton W. Fiske, Gerald R. Helbig, Donald S. Post.
United States Patent |
3,880,516 |
Post , et al. |
April 29, 1975 |
Diagnostic circuit board
Abstract
A diagnostic aid for use in a reproduction machine having a
counter incorporated therein to register the number of copies
produced by the machine. A circuit board, adapted for
interconnection with the control circuit of the machine is employed
to convert the copy counter into a timed pulse counting mechanism
to determine if sequenced events during machine operation occur
during the proper time interval.
Inventors: |
Post; Donald S. (Fairport,
NY), Helbig; Gerald R. (Webster, NY), Fiske; Kenton
W. (Fairport, NY) |
Assignee: |
Xerox Corporation (Stamford,
CT)
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Family
ID: |
26978364 |
Appl.
No.: |
05/444,997 |
Filed: |
February 22, 1974 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
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312396 |
Dec 5, 1972 |
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Current U.S.
Class: |
399/11; 399/78;
377/8; 377/16; 377/29 |
Current CPC
Class: |
G03G
15/55 (20130101) |
Current International
Class: |
G03G
15/00 (20060101); G03g 015/22 () |
Field of
Search: |
;355/14,3R ;324/181,73
;235/92SB,92T,92CT |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Matthews; Samuel S.
Assistant Examiner: Hutchison; Kenneth C.
Parent Case Text
This is a continuation-in-part application of application Ser. No.
312,396 filed Dec. 5, 1972, now abandoned.
Claims
What is claimed is:
1. In an electrostatic printing apparatus for reproducing copies of
an original having a plurality of processing stations arranged for
producing toner images of the original and the production of fixed
toner images on copy sheets, and sheet feed means for feeding copy
sheets through the apparatus, the improvement comprising:
a pulse producing means to produce a series of pulses for use as
timing signals,
control means connected to said pulse producing means to generate
control signals for activating one or more of the processing
stations at preselected pulses in said series;
counter means for registering the number of copies produced by the
apparatus;
detachably connected testing means for inhibiting said counter
means from registering the number of copies produced and for
interconnecting said pulse producing means, said control means, and
said counter means to cause said counter means to count the number
of pulses passing through said testing circuit means from said
pulse producing means to said counting means during a copy cycle;
and,
interrupting means for stopping said pulse from reaching said
counting means after said control means generates one of said
control signals.
2. An electrostatic printing apparatus for producing copies of an
original including:
a plurality of electrostatic processing stations for producing
toner images of the original for transfer to suitable copy
paper;
paper feed means for feeding copy paper through the apparatus for
transfer of the toner image thereto;
a pulse generator for providing a series of discrete pulses;
control means connected to said pulse generator to generate control
signals for activating said processing stations and said paper feed
means at preselected pulses in said series to produce toner images
and provide for proper registration of the toner images on the copy
paper;
counter means for registering the number of copies produced by the
apparatus;
testing circuit means detachably connectable to said counter means,
said pulse generator and said control means for inhibiting said
counter means from registering the number of copies produced and
for causing said counter means to count the number of pulses
passing through said testing circuit means from said pulse
generator to said counting means during a copy cycle; and,
interrupting means to prevent passage of pulses to said counting
means after said control means generates one of said control
signals.
3. An electrostatic printing apparatus for reproducing copies of an
original on a movable photoconductive member including:
a plurality of processing stations for producing a developed image
of the original on the photoconductive member;
drive means for moving the photoconductive member past said
processing stations;
paper feeding and transporting means for passing paper through the
apparatus for producing copies of the original thereon;
monitoring means for determining proper positioning of the copy
paper throughout its path of travel through the apparatus;
a pulse generator for producing a series of discrete pulses in
synchronism with said drive mechanism for each copy to be
produced;
control means connected to said pulse generator to activate said
processing stations, said paper feeding and transporting means, and
said monitoring means at preselected pulses in said series to
provide proper sequencing of the apparatus functions;
counter means for registering the number of copies produced by the
apparatus;
testing circuit means detachably connectable to said counter means,
said pulse generator and said control means for inhibiting said
counter means from registering the number of copies produced and
for causing said counter means to count the number of pulses
passing through said testing circuit means from said pulse
generator to said counting means during a copying cycle from a
first preselected control signal from said control means; and,
interrupting means to prevent passage of pulses to said counting
means after said control means generates a second, preselected
control signal.
4. An electrostatic printing apparatus for reproducing copies of an
original including:
an imaging member,
a plurality of processing stations for producing an image of the
original on said imaging member;
paper feeding and transporting means for passing paper through the
apparatus for receiving images of the original from said imaging
member;
a drive mechanism for driving said imaging member;
monitoring means for determining proper positioning of the copy
paper throughout its path of travel through the apparatus;
a pulse generator for producing a series of discrete pulses in
synchronism with said drive mechanism of the apparatus for each
copy to be produced;
control means connected to said pulse generator to activate said
processing stations, said paper feeding and transporting means and
said monitoring means at preselected pulses in said series to
provide proper sequencing of the apparatus functions; and,
counter means connected to said control means and said pulse
generator to register the numbers of the pulses in the pulse series
at which said control means activates said processing stations,
said paper feeding and transporting means and said monitoring
means.
5. In an electrostatic printing apparatus for reproducing copies of
an original having a plurality of processing stations arranged for
producing toner images of the original on copy paper and paper feed
means for feeding copy paper through the apparatus, the improvement
including:
means for producing a series of pulses utilizable in the control of
one or more of the processing stations,
control means connected to said pulse producing means for
activating one or more of the processing stations at preselected
pulses in said series,
counter means for registering the number of copies produced by the
apparatus; and,
testing circuit means, detachably connectable to said pulse
producing means, said control means and said counter means for
inhibiting said counter means from registering the number of copies
produced and for causing counter means to count the number of
pulses produced by said pulse generator from the initiation of a
copy cycle to the activation of at least one of said processing
stations or said paper feed means.
6. In an electrostatic printing apparatus for reproducing copies of
an original having a plurality of processing stations for producing
copies of the original and sheet feeding and transporting means for
passing sheets through the machine for producing copies of the
original thereon, the improvement including:
monitoring means for determining proper positioning of the copy
sheets throughout their path of travel through the apparatus;
a pulse generator for producing a discrete series of pulses for
each copy to be produced;
control means connected to said pulse generator to activate one or
more of the processing stations, the paper feeding and transporting
means and said monitoring means at preselected pulses to provide
proper sequencing of the apparatus functions; and,
counter means connected to said control means and said pulse
generator to register the number of the pulse in the pulse series
at which said control means activates said processing stations, and
paper feeding and transporting means and said monitoring means.
Description
BACKGROUND OF THE INVENTION
Electrostatic copying machines of the type using a photoconductive
layer for developing a latent electrostatic image of the document
to be copied and thereafter developing and transferring the image
to a copy sheet employ various processing stations for uniformly
charging, exposing and developing the photosensitive surface,
transferring the developed image to the copy sheet, fusing the
transferred image on the copy sheet, cleaning the photoreceptive
surface, etc. For high speed operation of this machine, it is
necessary to provide an accurately timed sequence of operation of
the processing stations in order to maintain proper registration of
all processing functions relative to the image. There must also be
provision for the efficient and accurate movement of sheets of copy
paper from the supply station to the transfer station of the
machine in timed sequence relative to the production of
electrostatic latent images, the development thereof, the proper
orientation of each sheet to the developed image, the energization
of various charging devices in the machine and all of the sensing
elements throughout the machine utilized to detect copy sheet
location, accurate positioning of the copy paper and the
possibility of paper jam. In order to monitor and initiate all of
the timed sequences and operations of the machine in a high speed
copier, an electronic control system may be employed.
In the event of a machine malfunction causing paper jams or
unacceptable copies, it may be necessary to determine if the
various time-related functions are occurring during the proper time
intervals or that the paper sensors are actually being energized at
the time when a paper should be present for sensing thereby.
In a high speed machine, it is extremely difficult to determine if
these timed events are occurring at the proper time in attempting
to diagnose a malfunctioning machine.
SUMMARY OF THE INVENTION
This invention relates to a reproduction machine having a copy
counter associated therewith to register the number of copies
produced by the machine. Means, adapted for connection to the
control circuit of the machine, are provided to convert the copy
counter into a timing mechanism to register the timed sequence or
interval at which the various machine functions occur.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an isometric view of a xerographic reproduction
machine.
FIG. 2 is a schematic sectional view of a reproduction machine.
FIG. 3A is an electrical schematic illustrating a portion of the
control circuit of the reproduction machine and a diagnostic board
connected thereto.
FIG. 3B is a time chart illustrating the initiation and termination
of a number of time related machine functions.
DESCRIPTION OF THE PREFERRED EMBODIMENT
For a general understanding of an electrostatic processing system
in which the invention may be incorporated, reference is had to
FIG. 2 in which various components of a system are schematically
illustrated. As in most electrostatic systems such as a xerographic
machine, a light image of an original to be reproduced is projected
onto the sensitized surface of a xerographic plate to form an
electrostatic latent image thereon. Thereafter, the latent image is
developed with an oppositely charged powder to form a xerographic
powder image corresponding to the latent image on the plate
surface. The powder image is then electrostatically transferred to
a support surface to which it may be fixed by a fusing device
whereby the powder image is caused to permanently adhere to the
support surface.
The electrostatically attractable developing material commonly used
in electrostatic reproduction systems comprises a pigmented
resinous powder referred to here as "toner", and a "carrier " of
larger granular beads formed from a material removed in the
triboelectric series from the toner so that a triboelectric charge
is generated between the toner powder and the granular carrier. The
carrier also provides mechanical control so that the toner can be
readily handled and brought into contact with the exposed
xerographic surface. The toner is then attracted to the
electrostatic latent image from the carrier to produce a visible
powder image on the xerographic surface.
In the illustrated machine, an original D to be copied is placed
upon a transparent support platen P fixedly arranged in a
illumination assembly generally indicated by the reference numeral
10. While upon the platen, an illumination system comprising two or
more lamps L and reflectors is flash energized to direct light rays
upon the original to produce image rays corresponding to the
informational areas on the original. The image rays are projected
by means of an optical system 11 to an exposure station A for
exposing the photosensitive surface of a moving xerographic plate
in the form of a flexible photoconductive belt 12. In moving in the
direction indicated by the arrow, prior to reaching the exposure
station A, that portion of the belt being exposed would have been
uniformly charged by a corona device 13 indicated at a belt run
extending between belt supporting rollers 14 and 15, the latter
being the drive roller for the belt. The exposure station extends
between the roller 14 and a third support roller 16. The belt run
between these rollers is encompassed entirely by the exposure
station for minimizing the space of the belt and its supporting
rollers.
The exposure of the belt to the light image discharges the
photoconductive layer in the areas struck by light whereby there
remains on the belt a latent electrostatic image in image
configuration corresponding to the light image projected from the
original on the support platen. As the belt surface continues its
movement, the electrostatic image passes around the roller 16 to a
developer station B located at a third run of the belt and in which
there is positioned developing apparatus generally indicated by the
reference numeral 17. The developer apparatus 17 comprises a
plurality of brushes which carry developer to the adjacent surface
of the upwardly moving inclined photoconductive belt 12 to provide
development of the electrostatic image.
The developed electrostatic image is transported by the belt 12 to
a transfer station C located at a point of tangency on the belt
around the drive roller 15 whereat a sheet of copy paper is moved
at a speed in synchronism with the moving belt in order to
accomplish transfer of a properly registered developed image.
There is also provided a copy sheet supplying apparatus comprising
a main paper feed supply 20 and an auxiliary paper feed supply 21.
Each of the paper supplies is adapted to separate sheets from their
respective supply stacks and to transport the sheets to a sheet
registration station and eventually into contact with the developed
image on the belt as the same is carried around the drive roller
15. A suitable timing control mechanism is operatively associated
with each of the paper supply mechanisms 20, 21 and the flash
illumination devices L, for producing an electrostatic latent image
on the belt 12 to present a developed image at the transfer station
C in timed sequence with the arrival of a sheet of paper, and is
coordinated with the activation of other processing and control
devices at the precise time that these elements are to function for
their intended purpose.
After the developed image is transferred to a sheet of paper, it is
stripped from the belt 12 and conveyed by conveying system 23 into
a fuser apparatus generally indicated by reference numeral 24
wherein the developed and transferred xerographic powder image on
the sheet material is affixed thereto. After fusing, the finished
copy is discharged from the apparatus by a conveyor 25 at a
suitable point for collection externally of the apparatus. The
toner particles remaining as residue on the developed image and
those particles not otherwise transferred are carried by the belt
12 to a cleaning apparatus 26 positioned on the run of the belt
between the rollers 14 and 15 adjacent the charging device 13. The
cleaning apparatus comprises a discharge device 27 for neutralizing
charges remaining on the particles and a rotating brush 28 which
operates in conjunction with a vacuum system to remove the residual
toner particles from the brush.
Belt 12 is driven by a drive means 30 comprising a constant speed
drive motor and gear box coupled to the drive roller 15 by a
suitable drive train or timing belt 31 interconnecting a sprocket
or pulley mounted on the shaft for the foller 15 and the drive
means output shaft 32.
Accurate sequencing of the various machine operations is provided
by a programming control including a pulse generator. The pulse
generator includes a gear 33 mounted on the motor drive shaft 32,
the gear including a predetermined number of teeth 34, each of
which becomes aligned with a stationary magnetic pickup element 35
during rotation of the gear. The element 35 is associated with a
generating device 36 which produces a square wave signal having
peaks corresponding to the successive alignment of the teeth 34
with the pickup element 35. As each tooth moves adjacent the device
35, the magnetic field in the device varies and thereby produces a
peak in the signal.
Thus a program control including the timing device mechanically
coupled to the shaft of the drive means 30 is operational whenever
the roller 15 is rotating. The pulse generating device 36, which is
part of the timing apparatus, is set to produce a continuous train
of timed pulses which is proportional to the rotational speed of
the drive means 30 and the number of teeth 34 on the gear 33. Any
machine event or processing step can be initiated, that is, turned
"on" and "off", or energized for any period of time, through
suitable control circuitry in response to a numbered pulse or
series of pulses from the timing device. For a more complete
description of the control system reference may be had to
application Ser. No. 284,835, filed Aug. 30, 1972 now U.S. Pat. No.
3,790,271.
In the event of a machine malfunction it may be necessary to
determine if a particular operation is occurring at the desired
pulse or for the desired number of pulses or if the various paper
sensors, paper feeder or other elements of the machine which are
operated in timed sequence are energized at the proper pulse.
In high speed machines of the type described, an electronic copy
counter 38 may be provided to count and register the number of
copies printed to enable the operator to follow the machine
programming and determine when the desired number of copies are
completed. This counter or copy count register 38, which may
operate in response to signals received from a paper sensor 39 at
the copy discharge portion of the machine, may be located on the
control panel 40 or console of the machine at a convenient location
such that it may be easily seen by the machine operator.
In order to determine if the various operations or sequence of
events within the machine are occurring at the proper timed pulses,
a diagnostic board 42 is provided which is adapted for
interconnection with the control system 44 of the machine. The
diagnostic board preferably is a simple electronic circuit adapted
to disengage the copy counter from the copy sensing device utilized
as the signal generator for the counter and electrically connect
the copy counter to the pulse generator to enable the counter to
count and register pulses generated thereby. If the paper sensor
signal provided to the copy counter is of the same voltage and
amperage as the pulses produced by the pulse generator, the circuit
could merely be a device to interrupt the signal from the paper
sensor to the copy counter and substitute the signals from the
pulse generator therefor. In the event the signals are of a
different voltage, the circuit board may contain devices for
reducing or increasing the signal from the pulse generator to
provide the required input to the counter. Upon energization of the
machine, a serviceman can easily determine if a machine operation
is occurring at the proper time or pulse by reading the pulse count
registered on the "copy counter " when the machine operation in
question was initiated, or the number of discrete pulses generated
during a particular machine operation to determine if the operation
or machine element was energized for the required period of time.
Since the copy counter is ordinarily in a very convenient and
easily visible location as an aid to the machine operator, it is
also in a logical position for employment by a machine serviceman
for diagnosing machine malfunctions. All that is required is a
simple circuit board which may be plugged into suitable connections
provided in the machine control circuit.
As stated heretofore, the diagnostic board described may be used to
test for proper operation of numerous electrostatic reproduction
machine functions. Typically, electrostatic reproduction machines
include means to implement processing steps such as document
feeding, copy sheet feeding, image exposure, pitch fadeout, edge
fadeout and transfer, and means to monitor the copy sheets as they
travel through the machine to sense jamming or stoppage of sheets
therein. Many or all of these functions may require precisely timed
operations.
To provide the necessary control, the machine may be provided with
control logic means for producing precisely timed control signals.
To derive these precise time signals, as illustrated in block
diagram form in FIG. 3A, the control means is provided with
synchronous section 51 which derives control signals from the
machine clock or pulse generator 36 and machine pitch information
from a pitch pulse generation means 53. For a more detailed
description of the control means, one may refer to the U.S.
applications, Ser. No. 438,972 filed on Feb. 4, 1974 or U.S. patent
application Ser. No. 445,013 concurrently filed herewith, both
applications being assigned to the assignee of the present
invention and expressly incorporated herein by reference. The
outputs of synchronous logic section 51 are utilized to actuate or
run the various elements of the machine which have to be precisely
timed.
As an example, the exposure lamp L must be triggered once every
pitch interval and the pitch fadeout lamp P must be turned on and
off at precisely timed intervals to discharge areas between the
images formed on the photoreceptor belt. For example, at start-up,
the pitch lamp is turned on by a print signal PR for a period of
time to clean the belt of any residual images. Then the first image
is flashed by applying a trigger signal pulse to the trigger
circuit 57 of the flash lamp. This is designed to occur at a
specific clock time, for example, clock pulse count signal 10, or
CPS 10. Once set, flash occurs at CPS 10 for every pitch interval.
As the leading edge of the image reaches the pitch fadeout lamp,
the lamp must be turned off. This may occur at CPS 110 or 100 clock
pulse signals after flashing of lamp L. After the image passes the
pitch lamp P is turned on again, for example, at CPS 750, to
coincide with the trailing edge of the image. To implement the
aforementioned operation, suitable logic network such as AND gate
61, inhibit gate 63, latch 65, are shown operatively connected in
FIG. 3A. It is to be understood that the logic network is merely
schematically shown to illustrate the logical operation involved.
For the more detailed description of the aforedescribed control
circuits, one may refer to the aforementioned applications and to
U.S. application Ser. No. 445,013 concurrently filed herewith,
assigned to the asignee of the instant case and expressly
incorporated herein by reference. It is evident from the foregoing
that the pitch lamp P be turned on and off at the correct time
interval to provide accurate pitch fadeout operation.
It is an aspect of the present invention to provide a suitable
diagnostic means for testing the machine functions, especially
those events which require critical timing of the operational
sequences or steps. FIG. 3A shows an exemplary embodiment of the
diagnostic board 42 in schematic form. It is to be understood from
the outset however that the circuit shown is for illustration and
not to be construed to limit the scope of the present invention to
such illustrated circuit only.
The board includes suitable circuitry having a coincidence gate
100, two latches 101, 103 and comparators 105 and 107 connected
operatively so that the gate 100 allows clock pulses to go
therethrough when the latch 101 is set and prevent passage of clock
pulses when the latch 103 is set. Note that the latches 101 and 103
can and should be reset initially using any suitable reset signal
via a switch means 109. The reset signal could come from the reset
or pitch pulse means 53 of the control means 44 via an input lead.
The input pairs 112 and 113 and 116 and 117 are respectively
connected to the positive or negative polarity terminals of the
comparators 105, 107. The comparators may be any well known devices
wherein when positive or negative going logic pulse or waves are
provided to inputs of matching polarity, they will provide an
output logic 1 or a set pulse. The input a of the AND gate 100 may
be connected to any suitable clock source such as clock 36 of the
machine.
Returning to the exposure lamp L and pitch fadeout lamp P
operation, one can readily see the application of the present
diagnostic board to test or measure the time interval between the
firing of the flash lamp L and the turning on or off of the pitch
fadeout lamp P. By connecting lead a of the AND gate 100 to the
clock 36, the input 112 to the exposure trigger signal path 62 and
the input 117 to the output of the inhibit gate 63, the measurement
between flashing of the exposure lamp at time t.sub.0 (FIG. 3B) and
turning off the pitch fadeout lamp P at time t.sub.1 is made in
terms of the clock count pulses. The clock pulses pass through the
AND gate between the time the latch is set, ie. its Q output goes
to logical 1 in response to the flash pulse applied to set lead s
via lead 112 and comparator 105, and the time latch 103 sets when
the inhibit gate output 63 goes negative at t.sub.1 as the pitch
fadeout lamp is turned off. The count may be registered in the
counter to the output of the AND gate 100.
The operator can readily measure the time between the exposure
flash and turning off the pitch fadeout lamp using the diagnostic
board armed with specific knowledge as to what the time interval
should be comparing it with the actual measured time interval. The
operator is then able to determine whether machine is functioning
properly or not and take necessary appropriate measures.
As another example, if for any reason the serviceman finds it
necessary to determine the length of time or the number of pulses
between images that the pitch fadeout lamp is on, he would be
instructed by his service manual to connect lead 112 to the line
between inhibit gate 63 and the pitch lamp and also connect lead
117 to the same point. Thus, the positive signal received through
lead 112 upon initiation or energization of the pitch lamp would
cause latch 101 to set and allow passage of clock pulses to the
counter. Upon de-energization of the lamp P, the latch 103 would be
set to prevent further passage of clock pulses to the counter.
Thus, the resulting count registered on the counter would be the
number of clock pulses during which the lamp was energized.
While the timing of flash and pitch fadeout has been used to
describe the subject invention, it can be seen that the diagnostic
board may be utilized to determine timing sequences of any timed
function of the machine, for example, the number of pulses after
flash at which a copy sheet is fed from the paper supply to the
transfer station to assure that the copy sheet arrives at the
transfer station in synchronism with the developed image on the
belt for transfer of the image to the copy sheet, etc. While only a
few examples have been mentioned, it should be readily apparent
that any two intervals of timed events signified by changes in the
signal from one to another level or polarity can be measured by
using the present circuit board.
Thus, by use of a simple diagnostic board, the copy counter on the
printing machine may be utilized when necessary as a pulse counter
to determine if the various machine operations and events are
occurring at the desired pulse produced by the control pulse
generator.
While we have described a preferred embodiment of our invention, it
is to be understood that the invention is not limited thereto, but
may be otherwise embodied within the scope of the following
claims.
* * * * *