Note: Descriptions are shown in the official language in which they were submitted.
- -
CROSS-REFhRENCE TO RELATED_APPLICATIONS . -
Reference is made to Canadian Patent A~plication
Serial No. 278,847 entitled APPARATUS FOR PRODUCING COLLATED
COPIES FROM lWO-SIDED ORIGINALS, filed in the name of
G. B. Gustafson on May 20, 1977; and Canadian Patent A~plication
Serial No. 278,846 entitled APPARATUS FOR PROD[JCING DUPLEX
COLLATED COPIES, filed in the name of JO Connin, also on
May 20, 1977u
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.2346S
This application is a d~visional of application S,N, 296,833, filed
13 February, 1978, and is directed to a document feeder'for feeding sheets
to an exposure position for copying while the paren~ application is directed
to a copier'including a process section, a document feeder'and a copy
`duplexing section. Another divisional application, S.N.3~)3~ filed
~6~ R`¦ Iq~ is also directed to a document feeder.
BACKGROUND OF THE INVENTION
The present invention relates to reproduction apparatus. More
specifically, the invention relates to convenience copiers having duplexing
capabilities and collating document feeders that invert the original document
sheets automatically, for producing duplex collated copies in page-sequential
order without a sorter.
It is well known in the prior art to provide convenience copiers
with duplexing capabilities, with document feeders that circulate the original
in a manner suitable for producing collated copies, or with document inverters ~ '
that present both faces of the document for copying. Examples include:
1) in relation to the first feature - U.S. Patent Numbers 3,31~,212; 3,536,398;
3,548,783; 3,615,129; 3,630,607; 3,645,615; 3,671,118; 3,672,765; 3,687,541; '; ;'
3,697,171; 3,775,102; 3,844,654; 3,856,295; 3,862,802; 3,866,904; 3,869,202; ~ '
3,947,270, and ''Research Disclosure", Vol. 142, No. 14237, February 1976 '~
(available from Industrial Opportunities Ltd., Homewell,~Havant, Hampshire,
P. O. 9-lEF, United Kingdom) 2) in relation to the second feature - U. S.
Patent Numbers RE 27,976; 3,552,739; 3,556,511; and 3,709,595; 3) and, in ~'
relation to the third feature U. S. Patent Numbers 3,227,444; 3,416,791 and '
3,675,999.
It is also known in the pTior art to combine certain of the above
mentioned features in a unified structure or control. U.S. Patent No.
3,630,607 might be cohsidered especially relevant in its disclosure of a ~
collating feeder on a convenience copier having duplex capabilities. U.S. ' ~'
Patent No. 3,844,653 discloses'a convenience copier having duplex capabilities ''
with a document inverting mechanism. U.S. Patent No. 3,862',802 discloses a
.,
3'1~i5
duplex copier with a document inverting mechanism, and is said to be usuable
with a sorter to produce collated copies. "Research Disclosurel', Vol. 133,
No. 13329, May 1975, discloses a manual approach for producing collated
duplex copies without a sorter.
,
:,
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.23~65
The cross-referenced patent applications Serial Nos.
278,846 and 278,847 present further improvemen~s in copy and
document handling. Both teach approaches capable of yielding
duplex or two-sided copies in a fully automa~ic ~anner, and
for collating the copies without the burden of a sorterO Both
also include collating, inverting document feeders and duplex-
ing copy processors that are particularly conduclve to simpli- -
fied finishing operations. One of the applications, Serial No.
278,847, includes advances for producing copies in page-
sequential order, thus enhancing still further the convenience
and efficiency of copying.
The above-mentioned patents and applications disclose
an impressive number of features for supplementing the basic ~
copying function to facilitate the total copying operation. ~;
Certain disadvantages remain, however, and it is to the allevia-
tion of these disadvantages that the present invention is
directed. In some cases, for example, prior approaches include
two document hoppers and a document preparation step. While
satisfactory for their intended purposes, the two hopper
approaches suffer from the disadvantages of multiple feeders,
extended guide channels and undesireable document preparation
steps. In addition, and referring now to copy handling aspects,
prior approaches suggest a "double pass" approach, where the
copy sheets are transported along a somewhat tortuous path
through the fuser and back to the photoconductor between the
transferring of images to opposite faces of the sheetsO Such
approaches, because of the intermediate fusing operation and
the effects it has on the copy-sheet condition, can complicate
copy handling~ StilL another problem relates to relatively
long copy-sheet paths. When short documents of two or three
pages are copied, for example, it may take longer for the
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~.23465
first copy sheet to return the second time to the photoconductor
than to present all of the other copy-sheets the first time,
This reduces the ability of the copier to handle all types of
jobs efficientlyO
SUMMARY OF THE XNVENTION
The present invent~on alleviates the above and other
deficiencies of prior copiers without sacrificing the advantages
of producing copies in page-sequential order. In accordance
with one feature, a copier can operate with simplex or duplex
originals in their usual sequence, so tha~ no particular prepara-
tion of the original is necessary prior or subsequent to copy-
ing. In accordance with another feature, images can be trans- -
ferred to both faces of a copy sheet prior to fusing, so that
the condition of the copy sheet, and especially its moisture :~
content, will be the same for both transfers. Still another :~
feature reduces the copy path from that required for conven~
tional double pass duplexing so that more types of jobs, and~
especially those concerned with documents of only a few pages, ; :~
can be run more efficiently,
In accordance with preferred embodiments of the
invention a document feeding section presents one or both faces
~~ of the original sheets to be copied, A process section estab- - ~
lishes representations of the original-sheet faces, A copy . .
duplexing section presents one or both faces of the copy sheets
to receive the representations established in the process :
section O
A preferred document feeding section receives the
originals face-up in their normal page-sequential order, re-
peatedly circulates the simplex or duplex document sheets for
copying one-sheet-after-another, in page-sequential order,
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13~.23~65
~last-page first, and returns the copied sheets to their original
page-sequential order. During each circulation of a duplex
document shee~, it is fed along a non-inverting path (i.e.~ -
it is inverted zero or even number of times) before it is copied.
Then it is inverted an odd number of times before it is copied
again, and finally an odd number of times before it is re~urned
face up to its original p~sition in its normal sequence. Dur-
ing each circulation of a simplex document sheet, it is inverted
an odd number of times before it is copied and an odd number of
times befoxe it is returned face up to its original position,
A copy section for use with such a feeding section
includes two transfer stations and between the stations there
is a copy sheet inverter. Means are provided for transporting
the copy sheets through the respective stations and inverter to
transfer ;muges to both faces of the copy sheets. Thereafter
the images are fused to the copy sheets. When simplex copies
are to be produced, one transfer station and the inverter are
bypassed
Still other aspects and more specific features will
become apparent to those skilled in the ar~ from the following
descriptions with reference to the accompanying drawings
BRIEF DESCRIPTION OF THE DRAWINGS ~ ~-
In the detailed description of the preferred embodi-
ment of the invention presented below~ reference is made to the
accompanying drawings, in which:
Figure 1 is a schematic representation of a copier
having simplex and duplex capabilities in accordance with a
preferred embodiment of the present invention;
Figure 2 is a schem~tic view depicting in general
suitable logic and control for use with the copier represented
in Figure l;
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Figure 3 is a schem~tic illustration of the feeder
depicted in Figure 1, but depicting additional structural
features thereof;
Figure 4 is a schematic view depicting the document
path and mode of operation of t~e document feeding section in
accordance with the preferred embodiment; and
Figure 5 is a schematic view depicting the copy path
and mode of operation of the copy processor in accordance with `~
the present invention and as described more fully in the
description of the preferred embodiment that follows.
:':
DESCRIPTION OF THE PREF RRED EMBODIMEN~
Referring now to the drawings, and especially to
Figure 1, a convenience copier is depicted in accordance with
a preferred embodiment of the present invention, comprising
a process section 3, a document feeding sec~ion 5, a copy
duplexing section 7, and a logic and control unit 9. The
process section 3 includes an imaging device or projector 10
and a processor 11 for establishing visible representations
of original document sheets, typically as image-wise distri- -~
butions of marking particles. The document feeding section
presents the original sheets to the process section for
establishing the visible representations, while the copy
duplexing section, in synchronism with the feeding section,
presents the copy sheets to the process section for receiving
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the visible representations forming the final copies. The
logic and control unit coordinates the operation of the
three sections as required.
The term "original" as used in the present appli-
cation refers to the object to be copied, including documents
and masters in cut or sheet form and comprising one or more
sheets or pages. A "sheet," "support" or "supporting medium"
of the original is used in reference to a single expanse of
thin, essentially flat material, such as paper, microfilm ~
or a transparency having two opposed faces or sides. A "page" ~ -
of an original is a face or side of one sheet bearing an
image, marking or information to be copied. A single sheet
or an original may include one or two pages depending on
whether one or both faces include material to be copied. A
"simplex" original includes one page per sheet; a "duplex"
original, two. Reference to sides or pages by number or as
"odd" or "even" refers to a sequential numbering of the sides
or pages in order from what conventionally is considered the
front of the original to its back, and does not depend on
how the pages are actually numbered. A simplex original would
have pages 1 and 2 on separate sheets. In a duplex original~
pages 1 and 2 conventionally would be on opposite sides of the ;~ -
same sheet. "Page-sequential order" refers-to the order:
page 1, page 2, page 3, page 4, etc, whether in connection with
simplex or duplex originals, and to the reversed order: page 4,
page 3, page 2, and page 1. ;
The term "copy" refers to duplicates of the original
in the usual sense, including receivers or supporting mediums -
and having sheets, faces or sides, and pages as those terms
3o are defined above. A "collated" copy is one that has its
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~ 65
pages in the same sequential order as the original, but not
necessarily the same page arrangement. A simplex original
can be duplex in its copy, and still be collated.
Process Section (Fig. 1)
The process section 3 can be selected from suitable
designs known to those skilled in the art, and a brief reference
to its general configuration is considered sufficient for the
purpose of the present specification. A scan/drum arrangement
is depicted in which the imaging device 10 includes scanning
optical and illumination mechanisms for viewing originals
placed on transparent platen 14, ~hile the processor 11 includes
a photoconductor 15 supported on a drum 16 for movement in
a cylindrical or closed path.
As the photoconductor moves in its path, it is acted
upon by various processing stations. Proceeding counterclock-
wise, in the direction of drum rotation, the photoconductor is
sensitized by a corona charger at station 17, is exposed by the
imaging device at station 19, is developed by a magnetic brush
at a station 21, moves through corona transfer and detack
stations to be described hereinafter, is erased by illuminators ^
and corona chargers at stations 25 and 26, respectively, and is
cleaned by a vacuum brush or the like at station 27. Two addi-
tional processing stations 28 and 29 are spaced from the photo-
conductor in a copy duplexing path. These stations include a -
registration device and fuser, respectively.
In operation, the imaging device 10 sequentially scans
the images from successlve original sheets onto successive frames
along the photoconductor, where visible representations of the ~
original sheets are established as image~wise distributions of -
marking particles which successively are transferrable to copy
~.2
taE~
sheets 9 A further description of the above-mentioned stations,
and the imaging device, is presented in Research Disclosure
Publication No. 14144, VolO 141, clated January 1976, published
by Industrial Opportunities, Ltd.,Homewell, Havant, Hampshire,
PO9 lEF, United Kingdom.
Other arrangements that could be modified to practice ;~
the invention in accordance with the teachings of the present
specification are disclosed in U.S. Patent Numbers 3,914,047 ~;
entitled SYNCHRONIZING CONTROL APP~RATUS FOR ELECTROPHOTOGRAPHIC
APPARATUS UTILIZING DIGITAL COMPUTER, issued on October 21,1975
in the name of William E. Hunt et al; and 3,876,106 entitled
TONER CONCENTRATION MONITORING APPARATUS UTILIZING PROGRAMMA~LE
DIGITAL COMPUTER, issued on April 8, 1975 in the name of
Stephen R Powell et al. These last-mentioned patents disclose ;
copiers of the so-called flash/web typeO ~
.:
Doc1 ~Pnt Feeding Section (Figures 1 and 3)
~ e document feeding section 5 includes a hopper 31,
a sheet presenting portion 33 and a sheet returning portion 35
The hopper is adapted to receive a set of original sheets face
20 up in their normal page-sequential order, to deliver the sheets
one-after-another, last sheet first, from the bottom of the docu-
ment set, and to receive the sheets, each sheet on top of pre-
viously delivered sheets, at the top of the document set, The
sheet presenting portion 33 removes the sheets sequentially from
one end at the bottom of the hopper,presents the removed sheet
with one face engaging the platen 14 for copy~ng, and then
re-presents the sheet with its other face engaging the platen,
Ihe sheet-returning portion 35 removes the sheet from the platen
after both of its faces have been copied and returns the sheet
to the hopper in the original order of the document set,
_g_
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~.234~i
- Referring now more specifically to the structural
details of the document feeding section, and to Figure 3 in
particular, the hopper 31 is located above and spaced from the
platen 14 where it is readily accessible for receiving and sup-
porting the set of original document sheets Of conventional
design, the hopper includes a sloping tray 37 for assisting in
aligning the document sheets against forward wall 38, suitable
side guides and joggers, not shown, and a set-completed detector
39 for determining, without counting, when (each time) the set ~ 'r
of original sheets has been copied. Further details of the
preferred hopper are illustrated and described in commonly
assigned British Patent No. 1,492,466, entitled RECIRCULATING
SHEET FEEDER FOR DOCUMENT COPYING, issued March 22, 1978 in the
name of Matthew J Russel.
The sheet presenting section 33 includes a first part
defined by an oscillating vacuum pick-off device 41, a driving
nip between ring 43 and back-up roller 45, and a sheet diverter
47; a second part including closed-end, non-inverting sheet path
61, 49, the curved portion 49 being generally in the shape of
~` a snail shell 49 and two driving rollers 51 and 53; and a third
part including means defining first and second sheet inverting
paths 55 and 57, respectively.
The first part of the sheet presenting section removes
the sheets from an exit 59 at one end of the hopper tr~y 37 and
directs the removed sheet into a selected one of the inverting
path 55 or non-inverting path 49, depending on the position of ~ `
diverter 47. As depicted more -fully in the above-mentioned
British Patent No. 1,492,466, the sheets are removed at first by
the vacuum pick-off device, which draws one end of the sheet out
i of the exit, and then by the driving nip, which propels the sheet
into the selected path.
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~L~.23~6S :.
The second part of the sheet presenting section directs
the removed sheet to the platen 14 without inverting the sheet;
or, stated differently, with the last face (even page) of the
document engaging the platen. In one sense, as men~ioned above,
this part defines a non-inverting document path leading from the
hopper to the platen~ In another sense~ however, it is a dis~
abling device which renders the in~erting path 55, through which
the sheets subsequently pass, ineffective to invert the sheetO
In operation, a sheet entering this part via diverter 47 will be
directed through path 61 and into the snail shell 49. m e motive
force of rollers 51 and 53 advance the sheet until the trailing
end of the sheet clears the diverter, The diverter is moved and
rollers 51 and 53 are then reversed to dri~e the sheet from the
non-inverting path into path 55 and then onto the platen 14. The
sheet is moved across the platen by rollers 670
The third part of the sheet-presenting section temporar~
ily removes the sheet from the platen, after the first face of
the sheet has been copied, and inverts or turns the sheet over for
copying its other face. This is accomplished by the rollers 67
~hich advance the sheet into the inverting path 57, and the driv- - ;
ing rollers 63 and 65, which propels the sheet around path 57,
through 360 degrees and back onto the platen.
A sheet registration and exposure station comprises
platen 14, rollers 67 and a registration gate 69. On entering
the exposure station, a document sheet is driven by the rollers
67 into a registered position~against the gate, After the first
face of the sheet is copied, the rollers are reversed, once to
drive the sheet into the second inverting path 57, and again to
re-register the sheet f~r copying the second faceO Then, after
the second face has been copied, the gate is remDved by solenoid
71 and the rollers 67 drive the sheet lnto the sheet returning
portion 35 of the feeder~
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The sheet returning portion 35 includes a sheet
inverting path 73 and two drive rollers 75 and 79 for returning
the document sheet from the platen to hopper 31 and on top of
the set from which it originally was removed.
The non-inverting path 6}, 49, as described above
maintains the original orientation of the sheet faces from the
hopper to the platen in the sense that the sheet, while it may
be -curled ~n the snail shell, is never turned over entirely.
It should be apparent to those skilled in the art, however, that
an even number o sheet inverSiQns also would present the sheet
to the platen with the same side down for copying~ The snail
shell could be eliminated, for example, and the inverting path
57 could then be used twice (i.e. an even nu~ber of times)
before copyingO This would present the original faces in the
same order as the structure described above. In similar respect,
the inverting paths 55, 57 and 73 could have one or any other ~-
odd number of inversions and still operate for the purpose
described~
The feeder is referred to sometimes as a circulating
or recirculating feeder because the sheets move in the feeder
repeatedly from the hopper to the exposure platen and back to
the hopper in a manner which simulates a closed-loop or
circuitous path. It is a collating feeder because it is
capable of feeding sheets in an appropriate sequence for produc- `
ing collated copies without a sorterO m is aspect of the feeder
will become more apparent from the following description. It `
is also a duplex~lg feeder in the sense that it can feed simplex
or duplex document sheets in a manner suitable for gene~ating
duplex copiesO
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l~.Z3a~65
For the purposes of simplifying this description, it
will be assumed throughout most of this specification that the
feeder and copier are operating in a collating duplexing mode
with a duplex originalO It should be understood, however, that
many of the feederls advantages re:Late to its flexibility and
convenience in other modes of operation. Such other modes
might include, for example, capabilities for eeding without. : ~
collating, for producing simplex copies from simplex originals, ~.
for producing duplex copies from simplex originals, and for :
producing simplex copies fro~ duplex originals, In the non-
collating mode, each page would be presented to the platen
once regardless of the number of copies to be made, When
making simplex, collated copies from simplex originals, the ~-
feeder would operate generally as described in the above-mention-
ed British Patent No. 1,492,466. The same would be true for .~:
duplex copies from simplex originals, insofar as the feeder is
concerned, but the copy duplexing section would present
both faces of the copy sheets to the photoconductor for
receiving visible representations as described hereinafterO
Copy uplexin~ Section (Figures 1 and ~
The copy duplexing section 7 includes one or more
supply hoppers 81, for receiving and sequentially feeding copy -
supports 82 to the process section, the registration device~ 28,
~3.~3~i5
,
first and second transfer stations 83 and 84 (Fig. 1), inclu-
ding transfer and detacking coronas 85, 86, 87, and 88, a
sheet inverter 89, a vacuum stripping roller 91 and an exit
hopper 93.
The supply hopper can be similar in many respects to
the hopper 31 of the document feeder, including a support tray
9~ and pick-off device 97 for withdrawing support sheets, one
after another, from a stack of such sheets, and for directing
the withdrawn sheets toward the photoconductor along suitable
guide channels.
Registration device 28 momentarily interrupts move-
ment of the copy sheets for their proper alignment with the
appropriate image frame on the photoconductor, after which the
sheets are directed into engagement with the photoconductor with
the same relative velocity as the photoconductor.
At the first transfer station 83j a D.C. transfer
corona 85 applies a charge to the face of the copy sheet
adjacent the charger. This electrostatically tacks the copy
,. ..
sheet to the photoconductor and transfers the visible repre-
sentation or image-wise distribution of marking particles,
formed by the previously described process section, from the
photoconductor to the copy support. The detacking corona 86,
an A.C. corona, then eliminates the electrostatic forces
tacking the copy to the photoconductor for facilitating the ¦
removal of the copy sheet from t-he photoconductor with the
visible image on the just removed face of the copy support. ~ ~
Sheet inverter 89 includes a relatively short .
vacuum transport 101, and stripping and diverting fingers 103,
for removing the sheet from the photoconductor and re-presenting
its opposite face thereto. The vacuum transport is coupled
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~3.~3~
to an appropriate source for maintaining a vacuum in end
roller 107 and plenum 109, which vacuum communica~es with
the copy support by way of perforations in belt 112. As the
copy support exits from the first detaching corona 83, it
is drawn off of the photoconductor and onto the belt 112
by the vacuum in roller 107. Stripping finger 103 also
may be of assistance, but pre~erably contacts-only that
face of the copy support which has not received an image,
since the image has not been fixed and may be somewhat easy
to smear. When the copy support is completely removed from
the photoconductor, and its trailing end has cleared the
diverting finger 103, the belt 112 is reversed for returning
the copy support to the photoconductor along path 113, de- ,~
fined by the diverting finger 103, with its other side en-
gaging the photoconductor and in registration with the next
appropriate image on the photoconductor.
The second transfer station 84 is substantially ~ ;
~den~ical to the first, and operates to transfer another
image to the face of the copy support then engaging the
photoconductor, after which the detacking corona 88 prepares
the support for its removal the second time from the photo-
conductor. This transfer and detack are accomplished ~ithout
disturbing the unfused toner on the first face Or the copy
support. ,
The vacuum stripping roller 91 draws the copy support ;
from the photoconductor and directs the support through the
fuser 29 and on to exit hopper 93, where each sheet is~de-
livered on top of previously delivered sheets, and with the
image last-transferred facing up. or course other stripping
devices could be used in place of the roller 91. In a copier
employing a flexible web, for example, the web may be trained
to follow a relatively sharp contour which will separate the
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~L~.Z346~;
_ .
copy support from the web. Similarly, once stripped from the
photoconductor, the copy support could be transported to the
fuser without contacting either face of the support. A number
of devices for accomplishing this purpose are available in the
prior art An exemplary device of this type is described and
illustrated in commonly assigned copending Canadian Application
Serial No. 295,455 filed on January 23, 1978 in the name of
Charles T. Hage et al.
The duplexing approach just described is referred to
as single-pass duplexing because no in~ermediate hopper is ~-
required Instead, the copy supports move directly from a
supply hopper to an exit hopper or finisher and with only a
single pass through a fuser. Other examples of single pass
duplexers are presented in previously referenced U.S. Patent
Numbers 3,672,765; 3,869,202 and 3,947,270.
Overall Operation
. . .
Referring now to the overall operation of the copier,
a document or other original comprising a set of individual
sheets is circulated and recirculated one-sheet-after-another
from the hopper 31 to the exposure station or platen 14 and back
to the hopper 31. Using the example of a six-page duplex origi-
nal, the sheet defining pages five and six is circulated first,
for copying page six and then page five, followed by the sheet
defining pages four and three and finally the sheet defining
pages two and one. The sheets are presented for copying in
sequential order, from page six to page one, and each page is
expos~d only once during each respective circulation, for produc-
ing collated copies without a sorter. Multiple copies of a set
of original sheets are generated by circulating and recirculating
the sheets a number of times equal to the number of set copies
desired
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3~6S
As the pages sequentially are presented for copying,
a succession of images representing the presented pages are
established in frames of the photoconductor, one~following-
another, in the same sequential order as the original pages
were presented, i.~., page 6, page 5, page 4, page 3, page 2
and page 1. The images are rendered visible at the development
station 21 and are moved by the rotating photoconductor into
position for sequential transfer to alternate sides of copy
supports at the first and second transfer stations 83 and 84
m e even pages would be transferred at the first station 83 and
the odd pages at the second station 84,
For each circulation or recirculation of a duplex ;
document sheet, it is presented twice for exposure and two images
are established. Similarly, one copy support is presented to
the process section for receiving the two images, first on one
face and then the other. The first copy support will receive
an image representing page six on one side and then page five
on the otherO The next copy support will receive pages four
and three, and the following copy support pages two and one.
Of course additional copies will be generated in the same order
and deposited on top of ~he earlier copies in the exit hopperO
Lo~ic and Control nit (Figures 1 and 2)
A logic and control unit for accomplishing the above "
modes o~ operation is depicted in Figures 1 and 2. Its function
generally is to coordinate the activities of the process section, ;
the feeding section, and the duplexing section, Such a co-~
ordinating function could be implemented by relays, transistors, ~
small and medium scale digital integrated circuits and the like. `
In this particular embodiment, a microcomputer 121 (Figure 2)
is utilized. The combination and sequential logic requirements
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~.~.23~5
of the process are established in a control program 129, which
provides instructions to a central processing unit 125 to
control the states of output signals, based upon the status
of input and timing signals. The timing signals can be de-
rived from incremental encoder 114 (Fig. 1) connected to the
drive means of the photoconductor drum, to provide information
required to relate the position of the moving photoconductor
to the positions of the fixed process stations.
The input and output signals are represented in
,~ Figure 1 by reference characters 139-154. Taken in order,
these characters identify control leads as follows:
139 leads to the registration gate 69,
of the document feeder, for controlling
its two positions (raised and lowered
or present and removed); -
140 leads to the set-completed detector 39
for counting the number of copies com-
pleted 3
141 leads to the sheet propelling rollers 67
for establishing their direction of
rotation;
142 leads to the sheet diverter 47, of the
document feeder, for controlling its
two positions (inverting and not in-
verting);
143 leads to propelling rollers 51 and 53
for determining their directions of
rotation; -~
144 leads to the illumination source 156 for
3a controlling the intensity of illumin-
ation and scanning control;
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346S
145 leads to the image projector 10 for
controlLing optical scanning in synchronism
with the illumination source; ~:
146 leads to the primary charger 17 for
maintaining uni~orm charging;
147 leads to the fuser 21 for bias control;
"C" and '~" lead to the shaft encoder ~or acquiring
timing signals (count and frame signals);
148 leads to sheet feeding roller 97 for '` :~
initiating sheet feeding from hopper 81;
149 leads to the transfer and detacking coronas
in the first transfer station for
transfer control;
150 leads to the turn around device 89 for ~ ~
determining the direction of movement ~ :
of belt 112; ~;
151 leads to the transfer and detacking coronas ~
87 and 88 in the second transfer station ~ --
again for transfer control;
152 leads to the stripping roller 91 for
controlling its stripping action; ~ ;~
153 leads to the fusing station 29 for tem- ~
perature control; and ~-
154 leads to the erase and cleaning stations
25, and 26, for controlling their in-
tensities o~ operation. .~ ~.
Of course additional leads could be applied as de-
sired to effect the intended operation, including on and off
operation of the various stations. Further descriptions of
suitable contr;~l devices are presented in pre~iously refer-
enced UOSO Patent ~umber 3,914,047, and in commonly assigned ~:
U.SO Defensive ~Iblication No. T957,006, entitled ORIGINAL : .
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DOCUMENT REARRANGEMENT APPARATUS FOR USE IN RECIRCULATING
FEEDERS, published April 5, 1977 in the name of M,G, Reid, et al.
Under the influence of the logic and control unit,
the presentation to the process section of the original and
copy sheets, and their inversion, is coordinated so that the
copies will be collated in the page-sequential order described
aboveO For each presentation of an original sheet, an exposure -
is made to establish a visible representation of one face of
that sheet, and for each visible representation that is estab-
lished, a copy sheet face is presented to receive it~ ~hus,the original and copy sheet faces are fed on a one-for-one basis.
This is not to say that there are an equal number of original
and copy sheets, which would not be the case, of course, when
multiple copies are generated, but rather that there is one-for-
one correspondence in the presentations of the respective sheet
faces to the process section. Nor is it intended that the
original and corresponding copy sheets must be ed at the same `
timeO Generally, the feeding of an original sheet is displaced
in time from the feeding of its corresponding copy sheet, either
forward or backward, depending upon the machine configuration.
The logic and control unit also tracks the copies as
they are made, and directs the document feeding and copy duplex-
ing sections so that the first and second faces of the copies
will properly correspond with the irst and second aces of the
original.
Offset stacking, stapling and other finishing opera-
tions have not been depictedO It is intended, however, that
such apparatus be controlled for operation in synchronism with
the copier, preferably by the logic and control unit 9O
It should be understood that the present invention
contemplates modes of operation that will account for the usual
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variations in originals. A duple~ original that ends on the
first face of the last sheet, for example, need not be copied
on the blank face. In a similar respect, it should be recog-
nized that all of the capabilities that are available in
accordance with the present invention need not be used in
every mode. Thus, the document feeder can have a non-collating
mode and a simplex mode in addition to its collating duplex mode
of operation.
Numerous advantages of the present invention now
should become apparent to those skilled in the art. A first
copy is completed on both sides before other copies are ini-
tiated. This reduces the first-copy time. Each copy sheet ;
passes through the fuser only once, and only after
receiving both of its images, so the sheets maintain their
optimal relatively humid condition in both transfer stations.
The total copy path from initial supply to final exit is re-
duced for improved copying efficiency, especially for docu-
ments of only a few pages, and no sorter is required.
Additionally, a relatively simple collating inverting document
feeder is rendered possible with only a single hopper while
retaining the convenience of face-up, ordered presentation of
the document to the feeder.
Although the invention has been described in detail
with particular reference to preferred embodiments thereof, it
will be readily understood that variations and modifications
can be effected within the spirit and scope of the invention
as described hereinabove and as defined in the appended claims.
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