An apparatus and method of use in which a first photoconductive belt arranged to move about an endless operative path in an electrophotographic printing machine is replaced by a second photoconductive belt. The leading marginal region of the second photoconductive belt is secured to the first photoconductive belt. As the first photoconductive belt moves about the operative path, it positions the second photoconductive belt thereabout. After the second photoconductive belt is positioned about the operative path, the first photoconductive belt is removed therefrom and separated from the second photoconductive belt. The leading marginal region of the second photoconductive belt is then secured to the trailing marginal region thereof.

This invention relates generally to an electrophotographic printing 
machine, and more particularly concerns an improved apparatus for 
replacing used photoconductive belts in the printing machine. 
In an electrophotographic printing machine, a photoconductive belt is 
charged to a substantially uniform potential so as to sensitize the 
surface thereof. The charged portion of the photoconductive belt is 
exposed to a light image of an original document being reproduced. 
Exposure of the charged photoconductive belt selectively dissipates the 
charge thereon in the irradiated area. This records an electrostatic 
latent image on the photoconductive belt corresponding to the 
informational areas contained within an original document being 
reproduced. After the electrostatic latent image is recorded on the 
photoconductive belt, the latent image is developed by bring a developer 
mix into contact therewith. Generally, the developer mix comprises toner 
particles adhering triboelectrically to carrier granules. The toner 
particles are attracted from the carrier granules to the latent image 
forming a toner powder image on the photoconductive belt. Next, the toner 
powder image is transferred from the photoconductive belt to a copy sheet. 
The copy sheet is then heated to permanently affix the toner powder image 
thereto. This general approach was disclosed by Carlson in U.S. Pat. No. 
2,297,691, and has been further amplified and described by many related 
patents in the art. 
Generally, when a photoconductive belt is employed in an 
electrophotographic printing machine, a section of the path is flat 
permitting a planar image of the original document to be flash exposed 
thereon. When the light intensity of the flash is sufficiently high, the 
exposure time may be of a sufficiently short duration to prevent blurring 
of the electrostatic latent image recorded on the continuously moving 
photoconductive belt. The short flash exposure of the original document 
facilitates high speeds in electrophotographic printing. 
Various types of materials have been devised for photoconductive belts. One 
well known material is made from a selenium alloy which is capable of 
producing a large number of copies before replacement is required. Another 
material may be of an organic type. However, the organic materials 
frequently have a shorter useful life and require more frequent 
replacement. 
Various types of devices have hereinbefore been developed to replace the 
photoconductive belt utilized in an electrophotographic printing machine. 
The following art appears to be relevant: 
U.S. Pat. No. 3,600.082 
Issued: Aug, 17, 1971 
Patentee: Knechtlel 
U.S. Pat. No. 3,619,050 
Issued: Nov. 9, 1971 
Patentee: Swanke 
U.S. Pat. No. 3,877,806 
Issued: Apr. 15, 1975 
Patentee: Schrempp et al. 
U.S. Pat. No. 3,984,241 
Issued: oct. 5, 1976 
Patentee: Schrempp et al. 
The pertinent portions of the foregoing art may be briefly summarized as 
follows: 
Knechtlel describes a photoconductive web which advances from a supply reel 
to a take-up reel. When it is desirable to install a new web, the unit is 
rocked to expose the path of travel of the web over the rollers. A new web 
is placed over the rollers with its leading end secured on the take-up 
reel. The unit is then returned to the operative position. Alternatively, 
the unit may be fed horizontally to expose the web path of travel. 
Swanke discloses a device for replacing a used electrophotosensitive web 
with a new one. The used web is attached to a tow bar. The tow bar 
separates the leading and trailing ends of the used web. The used web is 
then fed back into a cartridge for disposal. After the cartridge 
containing the used web has been removed from the printing machine, a new 
cartridge is inserted therein. The tow bar picks up the leading end of the 
new web and threads it through the machine. The trailing end of the web is 
then secured to the tow bar form a continuous web. 
The Schrempp et al. patents describe a photoconductive belt having a 
replacement segment located in a cartridge which moves with the belt 
around the operative path. The belt and cartridge form a unified assembly 
which is replaced in its entirety when the photoconductive belt is used. 
One end of the belt is connected to a supply reel with the other end being 
connected to a take-up reel. Both the supply reel and the take-up reel are 
located in the cartridge. As the photoconductive belt is driven around the 
operative path, incremental portions thereof are advanced from the supply 
spool and taken up on the take-up spool. 
In accordance with the features of the present invention, there is provided 
an apparatus for replacing a first photoconductive belt arranged to move 
about an endless operative path in an electrophotographic printing machine 
with a second photoconductive belt. The apparatus includes means for 
substantially permanently securing the leading marginal region of the 
second photoconductive belt to a portion of the first photoconductive 
belt. This enables the first photoconductive belt to move the second 
photoconductive belt about the operative path as it moves thereabout. 
Means are provided for removing the first photoconductive belt from the 
operative path after positioning the second photoconductive belt 
thereabout. The leading material region of the second photoconductive belt 
is then separated from the first photoconductive belt. Thereafter, means 
attach substantially permanently the leading marginal region of the second 
photoconductive belt to the trailing marginal region thereof.

While the present invention will hereinafter be described in connection 
with various preferred embodiments and methods of use thereof, it will be 
understood that it is not intended to limit the invention to these 
embodiments. 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 illustrative electrophotographic 
printing machine incorporating 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 the electrophotographic 
printing machine employing the photoconductive belt replenishment 
mechanism of the present invention therein. Although the belt 
replenishment mechanism is particularly well adapted for use in an 
electrophotographic printing machine, it will become evident from the 
following discussion that it is equally well suited for use in a wide 
variety of devices 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 FIG. 1 printing machine will 
be shown hereinafter schematically, and their operation described briefly 
with reference thereto. 
Turning now to FIG. 1, the electrophotographic printing machine employs a 
belt 10 having a organic photoconductive surface 12 secured releasably to 
a conductive substrate. Belt 10 moves in the direction of arrow 16 to 
advance successive portions of photoconductive surface 12 through the 
various processing stations disposed about the path of movement thereof. 
As shown, belt 10 is entrained about stripping roller 18, tension roller 
20, and drive roller 22. Tension roller 20 is mounted resiliently on a 
pair of springs (not shown) so as to maintain belt 10 under tension. End 
guides or flanges are positioned on both sides of tension roller 20 to 
define a passageway through which belt 10 passes. Drive roller 22 is in 
engagement with belt 10 and advances belt 10 in the direction of arrow 16. 
Roller 22 is rotated by motor 24 coupled thereto by suitable means, such 
as a belt drive (not shown). 
Belt 10 is designed to be periodically removed from the printing machine 
and replaced with a new photoconductive belt. This prevents copy quality 
degradation in the printing machine. The printing machine employs logic 
circuitry which includes a counter. The counter registers the number of 
copies reproduced. After a predetermined number of copies have been 
reproduced, e.g. 40,000, the replenishment mechanism, indicated generally 
by the reference numeral 26, is actuated. Initially, a new photoconductive 
belt is advanced from replenishment mechanism 26 and secured to the old 
photoconductive belt entrained about rollers 18, 20, and 22. The old 
photoconductive belt is then severed. Drive roller 22 is then actuated to 
advance the old photoconductive belt and the new photoconductive belts in 
the direction of arrow 16. This threads the new photoconductive belt about 
rollers 18, 20, and 22. After the new photoconductive belt has been 
threaded about rollers 18, 20 and 22, the old photoconductive belt is 
severed therefrom. At that time, the leading and trailing edges of the new 
photoconductive belt are secured to one another. This forms a continuous 
photoconductive belt which acts as a replacement for photoconductive belt 
removed from rollers 18, 20, and 22. Generally, at the initiation of the 
replenishment cycle, tension roller 20 is retracted slightly to reduce the 
tension in belt 10. This more readily permits the removal of the old 
photoconductive belt and the replacement therewith with a new 
photoconductive belt. After the new photoconductive belt has been threaded 
about rollers 18, 20 and 22, the leading and trailing edges thereof are 
secured to one another, tension roller 20 is returned to its operative 
position placing the new photoconductive belt under the desired tension. 
The new photoconductive belt is now in the operative position permitting 
the printing machine to be actuated to reproduce a new series of copies. 
The detailed structure of the various embodiments of replenishment 
mechanism 26 will be described hereinafter with reference to FIGS. 2 and 
3. 
With continued reference to FIG. 1, the operation of the 
electrophotographic printing machine will now be briefly described. 
Initially, a portion of photoconductive surface 12 passes through charging 
station A. At charging station A, a corona generating device, indicated 
generally by the reference numeral 28, charges photoconductive surface 12 
to a relatively high, substantially uniform potential. 
Next, the charged portion of photoconductive surface 12 is advanced through 
exposure station B. At exposure station B, an original document 30 is 
positioned face-down upon transparent platen 32. Lamps 34 flash light rays 
onto the original document. The light rays reflected from the original 
document are transmitted through lens 38 and focused onto the charged 
portion of photoconductive surface 12. The charged portion of 
photoconductive surface 12 is selectively discharged by the light image of 
the original document. This records an electrostatic latent image on 
photoconductive surface 12 which corresponds to the informational areas 
contained within original document 32. 
Thereafter, belt 10 advances the electrostatic latent image recorded 
thereon to development station C. At development station C, a magnetic 
brush developer roller 38 moves the developer mix into contact with the 
electrostatic latent image recorded on belt 10. The developer mix 
comprises carrier granules having toner particles adhering 
triboelectrically thereto. The magnetic brush developer roller forms a 
chain-like array of developer mix extending in an outwardly direction 
therefrom. The developer mix contacts the electrostatic latent image 
recorded on belt 10. The latent image attracts the toner particles from 
the carrier granules forming a toner powder image on photoconductive 
surface 12. 
The toner powder image deposited on photoconductive surface 12 is then 
advanced to transfer station D. At transfer station D, a sheet of support 
material 40 is positioned in contact with the toner powder image formed on 
photoconductive surface 12. transfer station D by a sheet feeding 
apparatus, indicated generally by the reference numeral 42. Preferably, 
sheet feeding apparatus 42 includes a feed roll 44 contacting the 
uppermost sheet of the stack 46 of sheets of support material. Chute 45 
directs the advancing sheet of support material into contact with 
photoconductive surface 12 in a timed sequence so that the toner powder 
image developed thereon contacts the advancing sheet of support material 
at transfer station D. 
Transfer station D includes a corona generating device 48 which applies a 
spray of ions to the backside of sheet 40. This attracts the toner powder 
image from photoconductive surface 12 to sheet 40. After transfer, sheet 
40 continues to move in the direction of arrow 50 and is separated from 
photoconductive surface 12 by a detack corona generating device (not 
shown) which neutralizes the charge causing sheet 40 to adhere to 
photoconductive surface 12. A conveyor system (not shown) advances sheet 
40 from belt 10 to fusing station E. 
Fusing station E includes a fuser assembly, indicated generally by the 
reference numeral 52, which permanently fixes the transferred toner powder 
image to sheet 40. Preferably, fuser assembly 52 includes a heated fuser 
roller 54 and a back-up roller 56. Sheet 40 passes between fuser roller 54 
and back-up roller 56 with the toner powder image contacting fuser roller 
54. In this manner, the toner powder image is permanently fixed to sheet 
40. After fusing, chute 58 guides the advancing sheet 40 to catch tray 60 
for subsequent removal from the printing machine by the operator. 
Invariably, after the sheet of support material is separated from 
photoconductive surface 12, some residual particles remain adhering 
thereto. These residual particles are removed from photoconductive surface 
12 at cleaning station F. Preferably, cleaning station F includes a 
rotatably mounted fiberous brush 62 in contact with photoconductive 
surface 12. The particles are cleaned from photoconductive surface 12 by 
the rotation of brush 62 in contact therewith. Subsequent to cleaning, a 
discharge lamp (not shown) floods photoconductive surface 12 with light to 
dissipate any residual electrostatic charge remaining thereon prior to the 
charging thereof for the next successive imaging cycle. 
It is believed that the foregoing description is sufficient for purposes of 
the present application to illustrate the general operation of an 
electrophotographic printing machine incorporating therein the 
photoconductive belt replenishment mechanism of the present invention. 
Referring now to the specific subject matter of the invention, FIG. 2 
depicts one embodiment of replenishment mechanism 26 in greater detail. As 
shown thereat, initially belt 10 is stopped, i.e. by de-energizing motor 
24 (FIG. 1). Thereafter, tension roller 20 is retracted to reduce the 
tension in belt 10 and replenishment mechanism 26 actuated. Replenishment 
mechanism 26 includes a supply spool 64 having a continuous web of 
photoconductive material wound thereabout. After belt 10 is stopped and 
the tension therein reduced, sprocket rollers 66 are energized to advance 
the leading marginal region of the photoconductive material (hereinafter 
referred to as the new photoconductive belt) wound about supply spool 64 
into contact with the old photoconductive belt 10. The leading marginal 
edge region of the new photoconductive belt has a strip of double sided 
pressure sensitive adhesive secured thereto. By way of example adhesive 
tape number 665 manufactured by the Minnesota Mining and Manufacturing 
Company performed reasonably satisfactorily. Rollers 68 are initially 
spaced apart to receive the leading marginal region of the new 
photoconductive belt contacting the old belt. Once the leading marginal 
region of the new belt and old belt are interposed therebetween, rollers 
68 are moved toward one another to apply pressure thereon so as to cement 
the leading marginal region of the new photoconductive belt to the old 
photoconductive belt. In this manner, the new photoconductive belt is 
secured to the old photoconductive belt. Sprocket drive rollers 66 are 
then disengaged. and sprocket drive rollers 70 engaged, However, drive 
rollers 76 are not energized and belt 10 remains substantially stationary. 
After sprocket drive roller 70 are engaged, cutter or knife 72 is 
energized.. Knife 72 cuts the old photoconductive belt forming a leading 
and trailing marginal region. Gate 74 is then pivoted in a downwardly 
direction, as indicated by arrow 76, so as to be aligned with cutter or 
knife 78 and fastner rollers 80. At this time, fastener rollers 68 are 
spaced from one another with sprocket drive rollers 70 being energized to 
advance the leading marginal region of the old photoconductive belt until 
it overlaps the trailing marginal region of the leader extending from 
take-up spool 82. The trailing marginal region of the leader extending 
from take-up spool 82 has an adhesive strip thereon. The adhesive strip is 
positioned in contact with the leading marginal region of the old 
photoconductive belt between fastener rollers 80. Fastener rollers 80 are 
energized to bring the rollers into contact with the overlapped leading 
marginal portion of the old photoconductive belt and the trailing marginal 
region of the leader extending from take-up spool 82. The pressure applied 
thereto cements the leading marginal region of the old photoconductive 
belt to the trailing marginal region of the belt leader extending from 
take-up spool 82. After securing the leading marginal region of the old 
photoconductive belt to the trailing marginal region of the take-up spool 
leader, sprocket drive rollers 70 are de-energized and fastener rollers 80 
are spaced from one another. Take-up spool 82 is then energized to wind 
the old photoconductive belt thereabout. As the old photoconductive belt 
is wound about take-up spool 82, the new photoconductive belt advances 
from supply spool 64 and is threaded about drive roller 22, stripping 
roller 18 and tension roller 20. After the trailing marginal region of the 
old photoconductive belt having the leading marginal region of the new 
photoconductive belt secured thereto passes through cutter 78, take-up 
spool 82 is de-energized. Cutter 78 is then energized severing the leading 
marginal region of the new photoconductive belt from the old 
photoconductive belt. Gate 74 is then pivoted in an upwardly direction, as 
indicated by arrow 84. Sprocket drive rollers 70 are once again energized 
advancing the leading marginal region of the new photoconductive belt 
between fastener rollers 68. The leading marginal region of the new 
photoconductive belt now overlaps a portion of the new photoconductive 
belt postitioned between fastner rollers 68. Fastener rollers 68 are 
energized to move toward one another. Since the portion of the new 
photoconductive belt overlapping with the leading marginal region thereof 
has an adhesive strip thereon, the pressure from fastening rollers 68 
cements the leading marginal region of the new photoconductive belt to the 
trailing portion of the new belt. Thereafter, cutter 86 is energized 
severing the trailing portion of the new photoconductive belt from the 
remaining web of photoconductive material wound about supply spool 64. 
Sprocket rollers 70 are then disengaged and pinch roller 88 is cammed away 
from drive roller 22. Roller 20 is then moved to the operative position 
placing the new photoconductive belt under the desired tension. 
Thereafter, motor 24 may be energized to rotate drive roller 22 so that 
the printing machine may reproduce a new series of copies. 
By way of example, a photosensor (not shown) is positioned prior to rollers 
70 so as to detect the passage of a belt seam. In this way, the belt is 
permitted to advance a pre-determined distance to enable the new belt to 
be threaded about the belt support rollers. All of the sprocket drive 
rollers are engaged and disengaged by suitable clutches. The fastening 
rollers and gates are moved by suitable solenoids coupled thereto. Each 
knife or cutter may be a hot wire. The machine logic, coupled to the 
photosensor detecting the belt seam, actuates the respective clutches and 
solenoids in a timed sequence to achieve the foregoing cycle of events. 
Turning now to FIG. 3, there is shown another embodiment of replenishment 
mechanism 26. As depicted thereat, a web of photoconductive material 
(hereinafter referred to as the new photoconductive belt) is wound about 
supply spool 90. Sprocket drive rollers 92 are energized to advance the 
leading marginal region of the new photoconductive belt into contact with 
the old photoconductive belt at fastening station 94. The leading marginal 
region of the new photoconductive belt has heat actuable cement thereon. A 
reasonable suitable cement is number AF 4060 manufactured by the Minnesota 
Mining and Manufacturing Company. Fastening station 94 includes a hot 
plate 96 actuated by switch 98, and a platen 100 for supporting the lead 
marginal region of the old photoconductive belt. Cam 102 pivots in the 
direction of arrow 104 raising the platen into contact with the overlapped 
portion of the leading marginal region of the new belt and the old 
photoconductive belt. Switch 98 is then closed coupling hot plate 96 to a 
voltage source. This produces sufficient heat to thermally melt the cement 
securing the leading marginal region of the new photoconductive belt to 
the old photoconductive belt. Thereafter, tension roller 20 (FIG. 1) is 
retracted reducing the tension in belt 10. Knife or cutter 106 is 
energized to sever the old photoconductive belt forming leading and 
trailing marginal regions thereof. Switch 98 is then opened and cam 102 
pivoted in a downwardly direction, as indicated by arrow 106, so as to 
move platen 100 away from photoconductive belt 10. Gate 108 is then 
pivoted in a downwardly direction, as indicated by arrow 110. Sprocket 
drive rollers 90 and 112 are energized to advance the old photoconductive 
belt in the direction of arrow 16 so as to thread the new photoconductive 
belt about rollers 18, 20, and 22. The leading marginal region of the old 
photoconductive belt moves into a guillotine cutter 114 which shreds the 
old photoconductive belt. Cutter 118 is mounted on gate 108 and pivots 
downwardly therewith. After the trailing marginal region of the old 
photoconductive belt has advanced into cutter 114, cutter 118 is 
energized. This severs the leading marginal region of the new 
photoconductive belt from the trailing marginal region of the old 
photoconductive belt. Gate 108 is then pivoted in the direction of arrow 
120 and the leading marginal region of the new photoconductive belt is 
advanced into fastening station 94 overlapping a trailing portion of the 
photoconductive belt having cement thereon. Once again, cam 102 is pivoted 
in the direction of arrow 104 raising platen 100 against the overlapped 
portions of the new photoconductive belt. Switch 98 is then closed heating 
hot plate 96 causing the overlapped portions of the new photoconductive 
belt to be secured to one another. Thereafter, cutter or knife 120 is 
energized severing the photoconductive belt entrained about rollers 18, 20 
and 22 from the remaining web of photoconductive material wound about 
supply spool 90. Sprocket drive rollers 90 and 112 are then de-energized 
and tension roller 20 is returned to the operative position placing the 
new photoconductive belt under the desired tension. Motor 24 may then be 
energized to drive drive roller 22 causing the new photoconductive belt to 
move about the operative path. The electrophotographic printing machine is 
now capable of reproducing a new series of copies. 
By way of example, a photosensor (not shown) is located before rollers 112 
so as to detect the passage of a belt seam. This enables the belt to 
advance a distance sufficient to be entrained about the support rollers. 
As previously indicated with regard to the embodiment depicted in FIG. 3, 
all of the sprocket drive rollers may be engaged and disengaged by 
suitable clutches. The gates are moved by suitable solenoids coupled 
thereto. Each knife or cutter may be a hot wire. The machine logic, 
coupled to the photosensor detecting the belt seam, energizes the 
respective clutches and solenoids in a timed sequence to achieve the 
foregoing cycle of events. 
In recapitulation, the electrophotographic printing machine of the present 
invention includes a replenishment mechanism which secures a new 
photoconductive belt to the old photoconductive belt. The old 
photoconductive belt is then cut defining leading and trailing marginal 
regions thereof. The new photoconductive belt, which is secured to the 
trailing marginal region of the old photoconductive belt, is threaded 
about the belt supports. After the trailing marginal region of the old 
photoconductive belt leaves the belt supports, it is cut from the new 
photoconductive belt. The leading marginal region of the new 
photoconductive belt is then secured to the trailing portion thereof. 
Thereupon, the new photoconductive belt is severed from the web of 
photoconductive material remaining wound on the supply spool. In this 
manner, an old photoconductive belt is replaced with a new photoconductive 
belt. 
It is, therefore, evident that there has been provided in accordance with 
the present invention, an apparatus for replenishing a photoconductive 
belt in an electrophotographic printing machine that fully satisfies the 
aims and advantages hereinbefore set forth. While this invention has been 
described in conjunction with specific embodiments and methods of use 
thereof, it will be evident that many alternatives, modifications and 
variations will be apparent to those skilled in the art. Accordingly, it 
is intended to embrace all such alternatives, modifications and variations 
as fall within the spirit and broad scope of the appended claims.