Non-image erase system for reproduction machines

A xerographic type reproduction machine having a photoreceptor, a platen for supporting a document to be copied, an exposure lamp, and optical means for transmitting image rays from the platen and the document thereon to the photoreceptor to create a latent electrostatic image of the document on the photoreceptor; an edge erase lamp, means forming a fiber optic type conduit for transmitting a band of light from the erase lamp onto the photoreceptor to erase any non-image areas adjoining the edge of the latent image, a movable shutter when disposed in a home position closes the fiber optic conduit and prevent exposure of the photoreceptor to the erase lamp whereby to obviate possible deterioration of the photoreceptor from excessive exposure by the erase lamp; a cover for the platen having a highly reflective interior; and control means responsive to the closure of the cover to retain the shutter in park position and rely on light reflected from the cover interior during exposure to erase the non-image areas without exposing the photoreceptor to the erase lamp, the control means responding to a reduction in image size to move the shutter in accordance with either the size of the copy sheets in process or the reduced image size so that light from the erase lamp is used to discharge the photoreceptor non-image area resulting from the reduction in image size, the control means further responding to disposition of the cover in an inoperative position to move the shutter in accordance with the size of the copy sheets in process to erase any photoreceptor non-image area with light from the erase lamp.

The invention relates to a system for erasing non-image areas on the 
photoreceptor of a xerographic type reproduction machine or printer, and 
more particularly, to an erasure system in which light from the document 
exposure lamp or lamps is normally used for this purpose with provision 
for use of a separate erase lamp in special operating circumstances. 
In reproduction machines or printers of the xerographic type, a latent 
electrostatic image of the original being reproduced or copied is formed 
on the photoconductive surface of machine photoreceptor. Thereafter, the 
latent electrostatic image is developed and transferred to a copy sheet. 
The transferred image is then fixed as by fusing to provide a permanent 
copy. 
In the aforedescribed process, certain areas of the photoreceptor, although 
conditioned for imaging, are unused. Some of these non-image areas occur 
before the first image in a series, between successive images, and after 
the last image in a series, and these are referred to collectively as the 
interdocument area. Other non-image areas, referred to as side edge areas, 
occur in the areas bordering the top and bottom edges of the image. 
Further, as will be understood by those skilled in the xerographic arts, 
the size of some or all of these non-image areas changes with changes in 
the size of the image produced. For example, where a reduced size image is 
made, the interdocument area and one or both of the side edge areas 
increase in size. 
Typically, in the case of the aforementioned interdocument areas, an 
exposure lamp is provided across the photoreceptor path, the lamp, which 
is normally referred to as an interdocument erase lamp, being exercised 
for brief moments in timed relation with movement of the photoreceptor and 
the placement of the latent electrostatic images thereon to erase the 
interdocument areas. To accommodate changes in image size, which as noted 
work to change the extent of the interdocument areas, a control is 
normally provided to operate the interdocument erase lamp for a time span 
associated with the size of the image currently being produced. 
However, erasure of the side edge areas is offtimes more difficult to 
achieve since the physical size or span of the erase light must be changed 
to accommodate changes in image size. In the past, multiple lamps of 
different size have been used as well as movable shutters to provide erase 
light whose extent is tailored to the image size. A further complication 
may also arise, namely, fatigue of the photoreceptor sections which are 
exposed to the erase lamp. Since normally the edge erase lamp or lamps, 
once adjusted for proper size as by setting a shutter or shutters, are 
held on continuously, the constant and sustained exposure of portions of 
the photoreceptor to light from the edge erase lamp or lamps, which to 
assure discharge are relatively bright, may fatigue the photoreceptor in 
these areas and result in premature failure of the photoreceptor areas 
exposed to the lamp or at least impairment of its operating properties. 
To overcome the above problems, there is provided a reproduction machine 
having at least one erase lamp for discharging unused non-imaged areas of 
the machine photoreceptor, a transparent platen for the document to be 
copied, at least one high intensity exposure lamp for illuminating the 
document to be copied on the platen, and a cover member for covering the 
entire platen when making copies to prevent escape of extraneous light, 
the cover member presenting a highly reflective surface to the platen 
adapted to reflect light from the exposure lamp escaping past the document 
being copied on the platen back to the photoreceptor whereby to discharge 
the non-imaged areas without using the erase lamp.

While the present invention will hereinafter be described in connection 
with a preferred embodiment thereof, it will be understood that it is not 
intended to limit the invention to that embodiment. On the contrary, it is 
intended to cover all alternatives, modifications and equivalents as may 
be included within the spirit and scope of the invention as defined by the 
appended claims. 
For a general understanding of the features of the present invention, 
reference is had to the drawings. In the drawings, like reference numerals 
have been used throughout to designate identical elements. FIG. 1 
schematically depicts the various components of an illustrative 
electrophotographic printing or reproduction machine 5 incorporating the 
edge erase control of the present invention therein. It will become 
evident from the following discussion that the invention is equally well 
suited for use in a wide variety of printing machines and is not 
necessarily limited in its application to the particular embodiment shown 
herein. 
Inasmuch as the art of electrophotographic printing is well known, the 
various processing stations employed in the machine 5 will be shown 
hereinafter schematically and their operation described briefly with 
reference thereto. 
As shown in FIG. 1, the illustrative reproduction machine 5 employs a belt 
10 having a photoconductive surface thereon. Preferably, the 
photoconductive surface is made from a selenium alloy. Belt 10 is driven 
by main drive motor 29 and moves in the direction of arrow 12 to advance 
successive portions of the photoconductive surface through the various 
processing stations disposed about the path of movement thereof. 
Initially, a portion of the photoconductive surface passes through charging 
station A. At charging station A, a corona generating device, indicated 
generally by the reference numeral 14, charges the photoconductive surface 
to a relatively high substantially uniform potential. 
Next, the charged portion of the photoconductive surface is advanced 
through imaging station B. At imaging station B, a document handling unit 
positions original documents 16 facedown over exposure system 23. The 
exposure system, indicated generally by reference numeral 23 includes an 
optical cavity 23' of suitable design and configuration with illumination 
lamp 20 in operative relationship with a transparent platen 18 for 
supporting the document 16 to be copied. The light rays reflected from 
document 16 are transmitted through lens 22. Lens 22 focuses the light 
image of original document 16 onto the charged portion of the 
photoconductive surface of belt 10 to selectively dissipate the charge 
thereof. This records an electrostatic latent image on the photoconductive 
surface which corresponds to the informational areas contained within the 
original document. Thereafter, belt 10 advances the electrostatic latent 
image recorded on the photoconductive surface to development station C. 
Platen 18 is mounted movably and arranged to move in the direction of 
arrows 24 to adjust the magnification of the original document being 
reproduced. Lens 22 moves in synchronism therewith so as to focus the 
light image of original document 16 onto the charged portion of the 
photoconductive surface of belt 10. 
As will appear, the document handling unit comprises a Semi-Automatic 
Document Handler (referred to herein as a SADH) 21. SADH 21 feeds the 
document 16, which may comprise a single sheet or computer form, forward 
into registered position on platen 18. Following processing, SADH 21 
discharges the document into a suitable output receptacle. 
While an SADH type of document handling unit is described herein, one 
skilled in the art will appreciate that other types of document handling 
units such as a recirculating document handler as well as manual systems 
may instead be contemplated. 
A plurality of sheet transports comprising a vertical transport 31, a 
registration transport 32, prefuser transport 33, decurler 34, post fuser 
transport 35, output transport 36, bypass transport 37, and inverter roll 
38, cooperate with suitable sheet guides 39 to form a paper through which 
the copy sheets 8 being processed pass from either main paper supply tray 
25, auxiliary paper supply tray 27, or duplex paper supply tray 60 through 
the machine 5, the finished copies being discharged into top tray 54 or 
output via discharge path 58 to an output module such as a sorter (SOR). 
Transports 31, 32, 33, 34, 35, 36, 37, 38 are suitably driven by main 
drive motor 29. Suitable sheet sensors are provided at the output of each 
paper tray 25, 27 and duplex tray 60 to detect feeding of a sheet 
therefrom. 
With continued reference to FIG. 1, at development station C, a pair of 
magnetic brush developer rollers, indicated generally by the reference 
numerals 26 and 28, bring a suitable developer material into contact with 
the electrostatic latent image. The latent image attracts toner particles 
from the carrier granules of the developer material to form a toner powder 
image on the photoconductive surface of belt 10. 
After the electrostatic latent image recorded on the photoconductive 
surface of belt 10 is developed, belt 10 advances the toner powder image 
to transfer station D. At transfer station D, a copy sheet is moved into 
transfer relation with the toner powder image. Transfer station D includes 
a corona generating device 30 which sprays ions onto the backside of the 
copy sheet. This attracts the toner powder image from the photoconductive 
surface of belt 10 to the sheet. After transfer, prefuser transport 33 
advances the sheet to fusing station E. 
Fusing station E includes a fuser assembly, indicated generally by the 
reference numeral 40, which permanently affixes the transferred powder 
image to the copy sheet. Preferably, fuser assembly 40 includes a heated 
fuser roller 42 and backup roller 44. The sheet passes between fuser 
roller 42 and backup roller 44 with the powder image contacting fuser 
roller 42. In this manner, the powder image is permanently affixed to the 
sheet. 
After fusing, decurler 34 and post fuser transport 35 carry the sheets to 
inverter gate 48 which functions as an inverter selector. When energized 
or pulled, gate 48 directs the copy sheets into a sheet inverter 50. When 
inoperative, gate 48 bypasses sheet inverter 50 and the sheets are fed 
directly to bypass gate 52. Thus, copy sheets which bypass inverter 50 
turn a 90.degree. corner in the paper path before reaching gate 52. Bypass 
gate 52 directs the sheets into top tray 54 so that the imaged side which 
has been transferred and fused is faceup. If inverter 50 is selected, the 
opposite is true, i.e. the last printed face is facedown. Bypass gate 52 
normally directs the sheet into top tray 54 or, when energized, to bypass 
transport 37 which carries the sheet to duplex gate 56. Gate 56 either 
directs the sheets without inversion to the discharge path 58 or, when 
energized, to duplex inverter roll 38. Inverter roll 38 inverts and 
directs the sheets to be duplexed into duplex tray 60. Duplex tray 60 
provides intermediate or buffer storage for those sheets which have been 
printed on one side and on which an image will be subsequently printed on 
the side opposed thereto, i.e. the copy sheets being duplexed. Due to the 
sheet inverting action of inverter roll 38, the buffer set of sheets are 
stacked in duplex tray 60 facedown in the order in which the sheets have 
been copied. 
In order to complete duplex copying, the previously simplexed sheets in 
tray 60 are fed seriatim by bottom feeder 62 back via vertical transport 
31 and registration transport 32 to transfer station D for transfer of the 
toner powder image to the opposed side of the sheet. Inasmuch as the 
bottommost sheet is fed from duplex tray 60, the proper or clean side of 
the copy sheet is positioned in contact with belt 10 at transfer station D 
so that the toner powder image thereon is transferred thereto. The duplex 
sheets are then fed through the same path as the previously simplexed 
sheets to the selected output for subsequent removal by the printing 
machine operator. 
Referring particularly to FIG. 2, reproduction machine 5 is segregated into 
a series of independent modules (termed remotes herein), and identified as 
sorter output remote (SOR) 9, paper handling remote (PHR) 11, marking and 
imaging remote (MIR) 13, xerographic remote (XER) 15, SADH remote 21, and 
central processing master (CPM) 19. FOR 9, PHR 11, MIR 13, XER 15, SADH 
21, and CPM 19 are communicated with one another by means of a shared 
communication line (SCL) 7 through which controlled instructions and 
synchronizing clock pulse signals from and to the machine remotes pass. 
Referring particularly to FIGS. 1 and 3, a suitable machine clock pulse 
generator 95, which is drivingly coupled to the output shaft of main drive 
motor 29, generates a succession of clock pulses whenever drive motor 29 
is energized. As will be understood, to enhance copy throughput, several 
copy sheets may be in process at various locations along the paper path at 
any one time. To accommodate this and permit individual copies to be 
tracked and processed in the particular manner desired, timing control 
over the copy processing functions is divided into pitches, each pitch 
being further subdivided into a number of machine clock pulses. For 
example, the paper path may be separated into eleven pitches with each pit 
being composed of approximately 850 machine clock pulses. 
Pitch reset signals, which serve in effect to determine the length of the 
pitch and the number of machine clock pulses within the pitch, are derived 
from copy sheet registration finger 96. For this purpose, a sensor such as 
switch 97 is disposed in the path of movement of copy sheet registration 
fingers 96 such that on each cycle of finger 96 past switch 97, switch 97 
outputs a reset signal. The output of machine clock pulses by generator 95 
are input through CPM 19 to PHR 11 while the pitch reset signals generated 
by switch 97 are input directly to PHR 11. 
Referring to FIGS. 4 and 5 of the drawings, main and auxiliary paper trays 
25, 27 each include a movable sheet elevator or base 41 onto which a 
stack-like supply of copy sheets 8 may be placed for use by the 
reproduction machine 5. A pair of sheet guides 46, 47 are provided for 
locating and retaining the copy sheets 8 in predetermined feeding position 
normal to the direction of sheet feed. A sheet stop 57 locates the copy 
sheets in the sheet feeding direction. 
The sheet guide 46 of both main and auxiliary trays 25, 27 is slideably 
supported within a slot-like opening 49 in base 41 to permit manual 
adjustment of guide 46 in accommodation of the size copy sheets 8 being 
processed. Sheet guide 46 is coupled through slot 49 with an elongated 
base member 55, the sides 55' which have predetermined relief or cutout 
portions which function to delineate the particular copy sheet size 
setting of the sheet guide 46. A pair of sensors 51, 53 are provided on 
either side of base member 55, arms 51', 53' of sensors 51, 53 riding 
against the sides 55' thereof. In the example shown, four copy sheet size 
settings are contemplated, one a copy sheet size of 9.5" to 11.2" in which 
sensors 51, 53 are closed and open respectively, a second a sheet size of 
11.2" to 11.9" in which both sensors 51, 53 are closed, a third a sheet 
size of 11.9" to 13.5" in which sensors 51, 53 are opened and closed 
respectively, and a fourth a sheet size in excess of 13.5" in which both 
sensors 51, 53 are open. 
A sheet feeder in the form of an endless belt 59 cooperates with a retard 
roll 61 to advance one sheet at a time forward to a take-away roll pair 63 
at a wait station 64 during operation of machine 5. On demand for a copy 
sheet, roll pair 63 is actuated to feed the sheet from wait station 64 
onto vertical transport 31. 
Referring now to FIGS. 6-8, SADH 21 operates, in a first or semi-automatic 
document handling mode to feed one document at a time placed in input tray 
68 by the user or operator automatically onto the platen 18 in registered 
position for copying. Following copying, SADH 21 removes the document from 
platen 18 and deposits the document in a suitable output tray provided for 
this purpose. In a second computer forms feeding copying mode, SADH 21 
operates to feed documents in the form of an endless web into registered 
position on platen 18 for copying page by page. In this mode, a suitable 
collector for computer form web (not shown) is provided. 
SADH 21 is hinged for opening and closing movement on reproduction machine 
5 at the back of machine 5, SADH 21 on opening thereof pivoting about an 
axis substantially parallel to the direction of document/computer form 
movement. This permits SADH 21 to be manually raised to an out of the way 
position as shown in FIG. 6 to expose platen 18 permitting the user or 
operator to manually place a document to be copied on platen 18 when 
operating in a third, manual copying mode. 
Pre-registration fingers 67 are provided for registering the leading edge 
of the document or computer form in proper position at the inlet to SADH 
21. Side registration guides 69 position the document or computer form 
laterally. Feed rollers 70, which are drivingly coupled to a suitable 
motor M1, cooperate with pinch rollers 71 to advance the document or 
computer form forward onto platen 18. A suitable document sensor 72 is 
provided adjacent pre-registration fingers 67 to detect the presence of 
the document or computer form leading edge and enable operation of SADH 
21. Pre-registration fingers 67 and feed rollers 70 are supported for 
pivotal movement such that on detection of the document leading edge by 
sensor 72, rollers 70 (which are normally raised) are moved downwardly to 
form a nip with idler rolls 71, while pre-registration fingers 67 (which 
are normally lowered) are raised up to permit the document or computer 
form to be carried forward onto platen 18. Suitable cam means may be 
provided for this purpose as will be understood by those skilled in the 
art. 
A platen clamp 77, which is mounted for limited raising and lowering 
movement on the underside of SADH 21 and which overlays platen 18 on 
closure of SADH 21 is provided. Clamp 77, when lowered serves to press the 
document or computer forms page on platen 18 against the platen surface. 
Clamp 77 is generally rectangular in shape with length and width 
dimensions equal to or slightly greater than the length (L) and width (W) 
of platen 18. As a result, clamp 77 overlays or covers the entire platen 
18 when SADH 21 is lowered into operative contact therewith. 
Clamp 77 is selectively raised and lowered by suitable means such as cams. 
Clamp 77 is raised when feeding a document or computer form forward onto 
or off of platen 18 (the position shown in FIG. 1) and lowered into light 
pressing engagement with the document or computer forms page on platen 18 
during exposure. 
To fed the document or computer form into imaging position on platen 18, an 
on-platen scuffer roller 80, drivingly coupled to a suitable servo motor 
M2 and mounted above clamp 77, is provided. Preferably roller 80 is 
positioned such that roller 80 is at a slight angle to the direction of 
feed. As a result, roller 80 both advances the document or computer form 
forward and sideways, the latter motion serving to bring the side edge of 
the document or computer form in engagement with a lateral registration 
edge 82. It is understood that where the width dimension of the document 
is equal to or less than the width (W) of platen 18 (which is the normal 
case), the document trailing edge exits feed rollers 70, 71 and 
accordingly comes under the sole control of scuffer roller 80. Where a 
computer forms web is being fed, the web normally remains in the nip of 
rollers 70, 71. To accommodate this, rollers 70, 71 are rotated for a 
predetermined time interval to assure, in cooperation with scuffer roller 
80, proper positioning of the computer forms page on platen 18. 
To align or register the document or computer form in proper position on 
platen 18, retractable registration fingers 74 are provided at the 
downstream edge of platen 18. Registration fingers 74 are selectively 
raised or lowered by a solenoid 76, fingers 74 being raised to intercept 
and register a document or the leading edge of a computer form being fed 
onto platen 18 and lowered to permit the document to be cleared from 
platen 18 and advancing and processing of successive pages of the computer 
form. 
A kickoff or ejecting roller 84 is mounted above clamp 77 downstream of 
scuffer roller 80. To facilitate the feeding action of scuffer roller 80 
and ejecting roller 84, the section 77' of clamp 77 (seen best in FIG. 8) 
housing rollers 80, 84 is independently mounted for limited pivotal 
movement. As a result, clamp section 77' depends downwardly into proximity 
with the surface of platen 18 opposite thereto when platen clamp 77 is 
raised during feeding of a document or computer forms page onto or off of 
platen 18. Both scuffer roller 80 and ejecting roller 84 are supported for 
controlled raising or lowering within associated apertures 80' 84' in 
clamp section 77'. Scuffer roller 80 and ejecting roller 84 are raised and 
lowered in a controlled manner by suitable means such as cams, roller 84 
being raised to permit the document or computer form to pass unimpeded 
when registering a document or computer form page on platen 18 while 
roller 80 is raised and roller 84 lowered when clearing the document page 
or advancing the computer form forward to the next page. To close off 
apertures 80', 84' in clamp section 77' during exposure when scuffer 
roller 80 and ejecting roller 84 are retracted, a movable shutter 87 is 
provided above clamp section 77' for interposition between the retracted 
rollers 80, 84 and the interior of clamp section 77' across apertures 80', 
84'. Shutter 87 is driven by a suitable cam operated linkage mechanism. To 
control and erase non-image areas, the bottom faces of clamp 77 and 
shutter 87 are covered by or made from a suitable light reflecting 
material such as white. 
When copying in either the first or second modes, the document or the 
leading edge of a computer form is abutted by the operator or user against 
pre-registration fingers 67 (fingers 67 are in a down position for this 
purpose) and lateral registration edge 69 with the document or computer 
form resting on input tray 68. 
On sensing the presence of the document or computer forms leading edge, a 
signal from sensor 72 to the machine CPM 19 lowers input roller 70 while 
raising pre-registration fingers 67. Feed rollers 70, 71, which are driven 
by motor M-1, cooperate to advance the document or the first computer 
forms page forward onto platen 18 in cooperation with scuffer roller 80, 
which is lowered at this point. Scuffer roller 80 is driven by motor M-2. 
The document or computer forms web is advanced across platen 18 by rollers 
70, 71 and 80 until the leading edge thereof abuts against registration 
fingers 74 which are raised for this purpose. Concurrently, the sideways 
motion imparted by scuffer roller 80 registers the side edge of the 
document or computer forms web against lateral registration edge 82. With 
registration completed, scuffer roller 80 and feed rollers 70 are raised 
while platen clamp 77 is lowered, the latter in cooperation with clamp 
section 77' pressing the document or computer form page flat against 
platen 18. Shutter 87 is also actuated to close off or shut apertures 80', 
84' in clamp section 77'. The document or computer form page on platen 18 
may then be exposed by reproduction machine 5. 
Following completion of the machine exposure cycle, clamp 77 is raised 
while shutter 87 is moved to a position where apertures 80' 84' for 
scuffer roller 80 and ejecting roller 84 are opened. Ejecting roller 84 is 
lowered into engagement with the document on platen 18 while registration 
gate solenoid 76 is actuated to drop registration fingers 74 and clear the 
exit path from platen 18. Ejecting roller 84 is driven at high speed by 
motor M2 to eject the document from platen 18. 
Where computer form is being processed, actuation of shutter 87 is 
inhibited while solenoid 76 is held actuated to retain registration 
fingers 74 retracted for processing of subsequent pages of the endless 
computer form. 
As the document or computer forms page is fed off on platen 18, the 
document or computer form is carried by take-away roller pair 88, 89, 
disposed adjacent to and on the downstream side of platen 18 and driven by 
motor M2, to the document output tray (when operating in the first mode) 
or to a suitable receptacle for collecting computer form (when operating 
in the second mode). 
While a SADH type of document handler has been illustrated herein, other 
document handler types and constructions such as Recirculating Document 
Handlers (RDH) may be envisioned as well as non-feeding manual platen 
covers. In all applications, however, the underside portions of the 
document handler or cover overlaying the platen are sized to cover the 
entire platen on closure thereof, the cover underside having a reflective 
surface for reflecting light and discharging the non-imaged areas of the 
photoreceptor belt 10 as will appear more fully herein. 
Referring now to FIGS. 10a, 10b, 10c, it will be understood that where for 
example multiple copies of a document or computer forms page are being 
made, a series of spaced latent electrostatic images 100 are created 
through exposure of the document or computer forms page on platen 18 to 
the moving photoreceptor belt 10. In the exemplary arrangement described 
heretofore, SADH 21 registers the document or computer forms page in one 
corner of platen 18. 
Where SADH 21 is not used, the operator or user is instructed to register 
the document or computer forms page against registration fingers 74 and 
lateral registration edge 82 in the corner of platen 18. As a result, one 
edge (identified herein for convenience as top edge 104) of the latent 
electrostatic image 100, whatever the image size, is fixed in position on 
photoreceptor belt 10. An undischarged non-image area, referred to as 
photoreceptor side edge 102 herein, exists between image edge 104 and the 
edge of belt 10 as well as a second undischarged non-image area, referred 
to as photoreceptor side edge 103 herein, between the bottom edge 105 of 
the maximum size image 100 and the opposite edge of belt 10. Further, 
where the document or computer forms page being copied is smaller in width 
than platen 18, an additional non-image area 103' occurs between the 
photoreceptor side edge 103 and the bottom edge 105 of the latent image 
100 as shown by FIGS. 10b and 10c. It is understood that since the 
document or computer forms page has one side registered against 
registration edge 82, a non-image area corresponding to non-image area 
103' does not normally occur between side edge 102 and top edge 104 of the 
latent image 100. 
Additionally, there are undischarged non image areas before the first 
image, between successive images, and after the last image. For 
explanation purposes, these areas are collectively referred to and 
identified herein as interdocument areas 106. As will appear, side edges 
102, 103 and any non-image area 103' are discharged to prevent unwanted 
development thereof as are the interdocument areas 106. 
On a reduction in image size, the non-image area 103' between the bottom 
edge 105 of the image and the photoreceptor side edge 103 as well as the 
interdocument area 106 increases in size. This is because, as demonstrated 
in FIGS. 10a, 10b, 10c, changes in the size of the image displaces the 
position of bottom edge 105 and the image sides 107. This in turn changes 
the physical size of the non-image area 103' and the interdocument area 
106 which must be discharged, i.e. erased, if development of these 
non-image areas is to be avoided. 
As described, platen 18 and lens 22 are mounted for movement in the 
direction shown by the solid line arrows of FIG. 1 to effect a change in 
size of the image 100. In the exemplary arrangement shown, movement of 
lens 22 as described effects a reduction in image size. Concurrently 
therewith, lens 22 is moved in a plane at right angles thereto as shown by 
the dotted line arrows in FIG. 1 to maintain the top edge 104 of the 
reduced image created (identified herein by numeral 100') fixed in 
position on belt 10. 
Referring to FIGS. 1 and 9, to erase or discharge the interdocument area 
106, the photoreceptor side edges 102, 103, and in certain cases the 
non-image area 103', interdocument and edge erase lamps 110, 117 are 
provided in the interior of the photoreceptor module 6. Interdocument 
erase lamp 110, the axial length of which is at least equal to the width 
of belt 10, is mounted at right angles to the direction of movement of 
belt 10 facing the inside surface of belt 10. As will be understood by 
those skilled in the xerographic arts, operation of interdocument erase 
lamp 110 is synchronized with movement of belt 10, lamp 110 being 
energized during periods when no image is present on belt 10 and being 
deenergized when an image is present. 
Edge erase lamp 117 is suitably supported within photoreceptor module 6 
with the axis of lamp 117 at right angles to the direction of movement of 
belt 10. The axial length of edge erase lamp 117 is at least equal to the 
width of belt 10. A plate-like light pipe 118 having a generally U shape 
is optically coupled between edge erase lamp 117 and the interior surface 
of photoreceptor belt 10. The light discharge edge 119 of light pipe 118 
facing belt 10 is defined by top and bottom edge erase segments 130, 131 
and central non-erase segment 132. Top edge erase segment 130 of light 
pipe 118 has an axial length equal to the width of the photoreceptor side 
edge 102 which due to the fixed registration point of image top edge 104, 
remains substantially constant whatever the size image being reproduced. 
Bottom edge erase segment 131 of light pipe 117 has an axial length equal 
to the sum of the photoreceptor side edge 103 plus the width of the 
largest size non-image area 103' to be erased. 
To enable the effective size of the bottom edge erase segment 131 of light 
pipe 117 to be adjusted in accordance with the size of the non-image area 
103' (it is understood that the size of the non-image area 103 changes 
with changes in the size of the image 100), an adjustable shutter 120 is 
interposed between the light discharge side 119 of light pipe 118 and belt 
10. Shutter 120 is supported by a shutter housing 114 positioned within 
the belt module 6. For this purpose, an elongated drive screw 122 is 
rotatably mounted in housing 114 alongside shutter 120. Screw 122 is 
coupled to shutter 120 through coupling member 123. A depending arm 121 on 
shutter 120 rides in a U-shaped track 124 on housing 114 to guide shutter 
120 back and forth upon rotation of drive screw 122. A suitable driving 
motor such as servo motor 125, is provided to drive shutter 120, the 
output shaft of motor 125 being coupled to screw 122 through transfer belt 
126 and gear 127. A shutter locating switch 135 cooperates with projection 
136 on member 123 to define the home or park position of shutter 120. In 
the arrangement shown, the shutter park position comprises the maximum 
closure position of shutter 120 relative to erase segment 131. This 
normally corresponds to the width of the photoreceptor side edge 103 as 
depicted in FIG. 10a. 
In order to avoid degradation of photoreceptor belt 10 through 
over-exposure of the non-image area 103' to light from edge erase lamp 
117, light from the reflective surfaces of platen clamp 77 and shutter 87 
of SADH 21 is instead used during exposure of the document or computer 
forms page on platen 18 to discharge area 103'. However, as can be 
understood, reflected light is not available when SADH 21 is in the raised 
position shown in FIG. 8, or when the size of the image 100 is reduced. 
Further, during reduction, and as illustrated by the example shown in FIGS. 
10b, 10c, non-reflecting or light absorbing structures within the optical 
cavity 23' may be unavoidably brought into the field of view. This can 
result from the multiple axis movement of lens 22, i.e. along a first axis 
away from platen 18 (shown by the solid line arrow in FIG. 1) and along a 
second axis paralleling platen 18 (as shown by the dotted line arrow in 
FIG. 1). Such multi-axis movement of lens 22 both changes and shifts the 
field of view of lens 22 so that peripheral parts of the illumination 
cavity may be brought into the field of view. In the example shown, the 
platen side edge 18', (see in FIG. 8) which is non-reflective, shows up as 
a faint black line 140 during reduction, the position of line 140 changing 
from a point outside the image area (an example of which is identified as 
point a in FIG. 10b) to a point just inside the image area (identified as 
point b in FIG. 10c). 
Where line 140, for the reduction mode selected, appears outside the image 
area, i.e. in the non-image area 103' as depicted in FIG. 10b, line 140 
is, as will appear, erased automatically with the discharge of non-image 
area 103' through the cooperation of edge erase lamp 117 and shutter 120. 
Where line 140 intrudes into the image area as depicted in FIG. 10c, 
shutter 120 is automatically adjusted to permit erasure not only the 
non-image area 103' but also the portion of the image 100' adjoining 
bottom edge 105 up to and including line 140. As will be understood, the 
minimal amount of image area being erased corresponds to the normally 
blank document boundary and hence the image content of the copy produced 
by reproduction machine 5 is not affected. 
OPERATION 
Operation of reproduction machine 5 to produce copies from documents or 
computer form pages on platen 18 is in the conventional xerographic manner 
understood by those skilled in the art. In that context, the document or 
computer forms page on platen 18 is illuminated by lamp 20, the resulting 
image rays being transmitted by lens 22 to photoreceptor belt 10 at 
exposure station B. There the belt 10, which was previously uniformly 
charged at charge station A by corotron 14, is exposed to create a latent 
electrostatic image of the document or computer forms page on belt 10. The 
latent electrostatic image is carried first by belt 10 to developing 
station C where the image is developed by developer rolls 26, 28 and 
thereafter to transfer station D where the developed image is transferred 
to a copy sheet supplied from either main or auxiliary paper trays 25, 27 
and brought forward on sheet transports 31, 32. 
Following transfer, the copy sheet is carried by transport 33 to fuser 40 
where the developed image is fixed and thereafter by decurler 43 and 
transport 35 to output tray 54, or selectively, by transport 37 and 
inverter roll 38 to discharge path 58. Optionally, inverter 50 may be 
actuated by setting inverter gate 48. Duplex copies are made by setting 
duplex gate 56 to route the copy into duplex tray 60 from which the copy 
is re-fed through the xerographic processing system to provide a second or 
duplex image on the reverse side of the copy sheet. 
Referring particularly to FIGS. 9, 11a, and 11b of the drawings and Table 
I, where reproduction machine 5 is first turned on, normally at the start 
of the day, a check is made to determine if edge fadeout shutter 120 is in 
the parked (i.e. HOME) position as defined by home switch 135. If the 
signal from switch 135 indicates shutter 120 to be in the home position, 
no further action is taken. Where however the signal from switch 135 
indicates shutter 120 is not in the home position, drive motor 125 is 
energized to drive shutter 120 to the home position as identified by 
switch 135. It is understood that this may result in movement of shutter 
120 in a direction opposite to that of switch 135 (i.e. away from the home 
position) followed by reverse movement of shutter 120 to the home 
position, since motor 125 operates drive screw 128 in one direction only. 
When shutter 120 is in the home position, motor 125 is deenergized. 
With shutter 120 in the home position (the position shown in FIG. 9), 
bottom edge erase segment 131 is sized to discharge the minimum non-image 
area (i.e. photoreceptor side edge 103) corresponding to the maximum size 
image 100 (as illustrated by the example of FIG. 10a) with energization of 
edge fade out lamp 117. Top edge erase segment 130, which is of 
predetermined fixed extent, is unaffected by the disposition of shutter 
120. Accordingly, on operation of reproduction machine 5, bands of light 
from edge fade out lamp 117 equal to the width dimension of photoreceptor 
side edges 102, 103 strike belt 10 and discharge or erase the 
photoreceptor side edges on energization of lamp 117. 
Where SADH 21 is used, SADH 21 is placed in the down postion over platen 18 
(shown in FIG. 6) and the leading edge of the document (semi-automatic 
document mode) or computer form (computer forms mode) to be copied 
manually inserted against pre-registration fingers 67 as described. With 
SADH 21 in position over platen 18, and no reduction selected, erasure of 
any non-image area 103' is effected through reflection of light from the 
reflective lower surface of SADH 21 which in the exemplary structure 
described comprises platen clamp 77 and shutter 87, it being understood 
that shutter 87 is in position covering apertures 80', 84' in clamp 
segment 77' during exposure. 
On detection of the document or computer forms leading edge by sensor 72, 
the document or first page of the computer form is carried forward into 
registered position against registration fingers 74 and lateral 
registration edge 82 as described. With the document or computer forms 
page in registered position on platen 18, scuffer roller 80 is raised, 
platen clamp 77 lowered, and shutter 87 moved to a position overlaying or 
covering apertures 80', 84' for scuffer and ejecting rollers 80, 84 
respectively in clamp segment 77'. As a result, a continuous highly 
reflective surface composed of clamp 77, clamp segment 77', and the 
portions of shutter 87 opposite apertures 80', 84' overlaying platen 18 is 
provided. 
Where no change in image size, i.e. reduction, is selected by the operator 
or user, on actuation of reproduction machine 5 to make copies (START 
PRINT PUSHED?), a check is made to determine if the platen cover, in this 
case SADH 21, is closed (COVER CLOSED?). With shutter 120 parked and SADH 
21 closed, machine 5 operates to make the copy or copies programmed. Edge 
erase lamp 117 is energized to erase the photoreceptor side edges 102, 103 
while the reflective surface presented by clamp 77, clamp segment 77', and 
shutter 87 of SADH 21 is relied on to discharge any non-image area 103' 
laying between the photoreceptor side edges 102, 103 and the top and 
bottom edges 104, 105 of the latent image 100. Since the document or 
computer forms page is placed in predetermined registered position on 
platen 18 with one side against lateral registration edge 82, any 
non-image area 103 will occur in the space between photoreceptor side edge 
103 and edge 105 of image 100. 
Should reproduction machine 5 go into standby during the copy run, 
actuation of the start/print button (START/PRINT PUSHED AGAIN?) causes a 
recheck to be made to determine if SADH 21 is still closed (COVER 
CLOSED?). If so, reproduction machine 5 is operated to make copies. 
In the event the platen cover, i.e. SADH 21, is opened as shown in FIG. 8, 
edge fade out lamp 117 is relied upon to discharge both the photoreceptor 
side edges 102,103 and any non-image area 103'. In that event the size of 
the copy sheet being fed from the paper tray in use, i.e. main or 
auxiliary tray 25, 27 respectively, is determined from the signal output 
of paper size sensors 51, 53 in accordance with the setting of the paper 
guide 46 for the tray in use (Tables II-VI). If the copy sheet size is the 
same as the size for which edge face out shutter 120 is then set (IS 
SHUTTER AT CORRECT SIZE?), no change in shutter position is required. 
Reproduction machine 5 is accordingly enabled (MAKE COPIES). 
In the exemplary arrangement described, shutter 120 is normally positioned 
in the home position. As a result, bottom edge erase segment 131 is set to 
discharge the photoreceptor side edge 103 on energization of edge fade out 
lamp 117. As described, the top edge erase segment 130 for erasing 
non-image area 102 is preset to the size of side edge 102 which, due to 
the fixed registration point for the document or computer forms page on 
platen 18, is constant. 
Where the paper size is determined to require re-positioning of shutter 
120, shutter 120 is moved by controlled energization of shutter drive 
motor 125. For this purpose, the desired position of the shutter 120 is 
calculated (DETERMINE DESIRED POSITION; Table IV), the shutter movement 
required being expressed in terms of clock counts (Required Pulses). 
Shutter 120 is then postioned (POSITION SHUTTER; Table V) by energizing 
motor 125(MOVE SHUTTER; Table VI) until the required number of pulses 
(Required Pulses) are obtained. It will be understood that the number of 
clock pulses required (Required Pulses) is equal to the number of clock 
counts representing the present position of shutter 120 (Shutter Position) 
plus the number of pulses required to bring the shutter from the existing 
shutter position to the desired position (Received Pulses). On shutter 120 
reaching the desired position, operation of shutter drive motor 125 is 
terminated and reproduction machine 5 enabled (MAKE COPIES). 
Where the operator or user changes image size, i.e. selects reduction, the 
image size (I.S.) is calculated (CALCULATE IMAGE SIZE) based on the 
reduction selected (Table IV). A comparison is made between the calculated 
image size (I.S.) and the paper size (P.S.), i.e. the size of the copy 
sheet in use, the latter being determined from the setting of the tray 
guide 46 in the paper tray in use as described heretofore. Where the image 
size (I.S.) is greater than the paper size (P.S.), i.e. (I.S.&gt;P.S.), 
shutter 120 is positioned in accordance with the size paper in use. In 
this situation, line 140, because the image is larger than the copy paper, 
appears outside the copy paper edge and in the non-image area 103'. Line 
140 accordingly will be erased along with the photoreceptor side edge 103 
and the non-image area 103' by edge erase lamp 117. 
Where the image size (I.S.) is equal to or less than the paper size (P.S.), 
i.e. I.S..ltoreq.P.S.), shutter 120 is positioned in accordance with the 
image size to assure erasure of line 140 as well as the non-image area 
103' by edge erase lamp 117. 
While the invention has been described with reference to the structure 
disclosed, it is not confined to the details set forth, but is intended to 
cover such modifications or changes as may come within the scope of the 
following claims. 
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