Note: Descriptions are shown in the official language in which they were submitted.
s~ .
Field o~ the InYention
This invention xelates to a photocopy machine. More
specific~lly~ this invention relates to a photocopy machine
using a photoconductor belt.
sackgrouhd of the Invention
The xerographic photocopying process has been exten-
siyely described and is well understood. Typically, a photo-
conductiye material is mounted on a drum or on an endless belt
to hold a latent electrostatic charge image prior to develop
~ent and transfer to a plain paper copy.
In one type of photocopy machine a photoconductor
drum is employed. While the drum is rotated it is exposed
to a line image of an object by the relative movement between
.. .
a, sl~t and an illuminated object. In another type of photocopy
' m~chine the drum is replaced with a photoconductor belt which
may be endless for continuous motion along a belt path. The ;
~elt path is defined by a plurality of roller elements which
are spaced to provide a belt path section where the belt is
,f,lat while being exposed to a planar image of the object
~nstead of through a moving line image.
~ The flat photoconductor belt section may be flash
;; exposed. ~When the light intensity oE the flash is sufficiently
high, the exposure time may be so short that blurring of the
la~tent image on a continuously moving photoconductor belt is
reyented, The short flash exposure of the entire object
26 enables a high speed photocopying operat~on.
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1C~48591
Various materials haye been proposed fo~ photo~
çonductors in photocop~ machines, One well known material
is made of a selenium material which is capable o~ producing
~ substantial number of copies before replacement. Another
material m~y be o~ the organ~c type such as described in the
U, S. patent to Shattuck et al 3,484,237. However, an orgànic
photoconductor material has a limlted useful li~e and thus
~e~uires replacement ~n a manner such as, for example, taught
~nd shown in the U. S. patent to Berlier et al 3,588,242.
In the Berlier patent a copy drum is described
utilizing an organic photoconductor stored as a flexible strip
on a supply reel located within the interior of the drum.
The photoconductor is fed around the external periphery of
the drum and returned to a take-up reel located inside the
drum. The entire photoconductor strip used on the drum is
periodically automatically replaced with a fresh unused
photoconductor on the supply reel after a certain preselected
number of copies have been made.
Another approach for replacing a photoconductor
belt is described in the U. S. patent to Swanke 3,619,050.
In this patent a photoconductor web is stored in a cartridge
located near a photoconductor belt path. A photoconductor
segment is ~ormed into an endless belt by use of a connecting
tow ba~ and wrapped axound appropriate roller elements which
define the photoconductor belt path necessary for exposure,
txans~er and development of the copy. A replacement of the
u~ed ~eb is c~rried out by tak~ng selected segments ~rom
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1048591
the nearby available c~rtrldge su~ply ~nd feeding thls around
the rollers and then reconnecting the ends at the two bars
to fo~m an endless belt. A complex mechanlsm for replace- ;
~ent of the photoconductor is described involving substantial
~anu~l contxol.
In the German patent publication 2,309,296, publish-
ed on September 6, 1973, based upon an application date of
~ebruary 24, 1973, a photoconductor is formed into an endless
loop. The loop forms a remo~able cassette having a supply
10 , ,roll and take-up roll. The loop is passed around rollers ~ '
~nd a copy platform around which an exposure area and a print-
~n~ stage are closely grouped. The cassette moves back and
~orth ~long a straight path during the copying process. ~ ,
' .: ' '
The desirability of using a flash exposure of a
flat photoconductor segment may be appreciated. The moving ~ ~ ,sl,i:t mechanism to expose a drum-type photocopier with a line
segment is deleted and a relatively convenient and economical
optical exposure system can be used. This advantage of the
~elt photocopier may be appreciated from the large number of '~
b,elt photocopiers described in the art such as in the U. S. '
patents to Gardner et al 3,521,950, Hewes et al, 3,661,452
and ~wanke 3,619,050.
:
Although the photoconductor drum structure disclosed
~n the Berlier patent effectively provides a long life by
yirtue of the storage of a replacement section within the drum,
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1C~48591
the Berlier appaxatus still operates with ~ line se~ment
exposu~e by ~irtue of its drum ~ounting and does not lend
itSelf to the photoconductor belt photocopy machine.
Rnother disadva~t~ge of the Berlier replacement
structure inYolves the photoconductor belt replacement opera-
~ion. This is carried out after a preselected number of copies
haye been made. At such t~me the entire photocopying process
i~s, interrupted until the cycle for replacement of the photo-
conductor seg~ent extending aro~nd the entire drum is completed.
.
The U. S. patent to Begun et al 2,789,776 discloses
- a,n apparatus manually positioning successive lengths of a
recording medtum on an endless reco~ding track such as on the
pexiphery of a rotating drum. Ratchet wheels are employed ,'
to pull successiye lengths of the recording medium around the '
, periphery of the drum to expose new lengths for recording '
playback.
,~ Although in a photocopy machine one could employ a
longer copying llfe selenium type photoconductor, its cost
and manufactur~ng complexities reduce the desirability for
such approach; particularly when the selenium photoconductor
~n the belt form has a significantl~ less useful lifetime
, than selenium in the drum shape.
,~ . , ~.
When an organic photoconductor is employed in a
' belt ~orm such'as shown in the appaxatus disclosed in the
,~ , p,a,tent to S~anke, then an undesirable frequent replacement
~peFation must be carried out even though the organic photo-
2~ conductor ~s retained in a nearb~ cartridge.
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16)4~591
Summary o~ the InYention
In a photocop~ machine in accordance with the
invention, a photoconductor assembly is formed of a photo-
c~nductor belt and a cartridge for storing a fresh supply
of photoconductor material. The photoconductor belt and
~ rtridge are moved around a belt path formed for a roller
assembly. The rollers in the roller assembly are each pro-
~' yided with a cartridge receiving recess sized to enable the
,~ ca~tridge to mesh with a roller as the belt and cartridge
pass oyer a roller. In this manner the photoconductor belt
assembly moVes in a continuous manner and in a uniform direc-
t~on around the belt path.
An advantageous feature of this invention involves
belt advance mechanism which automatically continually and
incrementally replaces the photoconductor belt with fresh seg-
~ents. The incremental advance results in a gradual replace-
~ent of the photoconductor belt as copies are being made with
an advantageously consistent level of copy quality throughout
, the useful life of the belt. The incremental replacement
further adYantageously distributes physical stresses over
the length of the photoconductor belt thus reducing the like-
J lihood of physical damage to any one segment.
:, ' , ' .:
, As described with respect to the preferred embodi-
'~ ment, the incremental advance of the photoconductor belt
~ ~nyolves ~ Geneva drive whose rotational output is reduced to
,j rotate a belt take-up reel located in the cartridge. ~he
Geneva drive may be actuated once during each full copy cycle
28 o~ the photoconductor belt. The xesultant incremental rotation
.~ :.
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of the take-up reel produces a corresponding incremental replace-
ment of the photoconductor belt, After a large number of copies
haye been made, the photoconductor belt segment which was
used to make copies h~s ~een replaced with a corresponding
fresh seg~ent from the cartridg~.
The cartridge is sized to retain a sufficient supply
o~ photoconductor belt material for a satisfactory lifetime
o~ nu~ber of copies, Yet the cartridge is sufficiently light
,; . .
, in weight to enable the photoconductor belt to support the ~ ~,
cartxidge throughout a copy cycle. The cartridge receiving ,~
, recesses in the rollers are provided with covers whose open-
. .j
,` ~ng and closing of the recesses are timed with the respective
, ar~val and departure of the cartridge at and from a recess.
, The covers are curved to provide a continuous cylindrical
~-' peripheral roller surface when the cartridge is between the
,rollers, When the cartridge enters a recess the covers are
; opened and the cartridge permitted to make a smooth entry
~nto the recess for a correspond~ngly smooth passage past
a roller. In this'manner a continuous photoconductor belt
motion is accommodated with a travelling belt-replacing
cartridge.
,; It is, therefore, an object of the invention to
,,
'~ proyide a photocopy machine of the belt type wi,th an effect-
~ yely long cycle life for the photoconductor. It is still
:i! ,$urther an ob~ect of the invention to provide a roller assem-
~ for use in a belt type photocopy machine to enable a
',~ p~otoconductor belt carrying a replacement segment to be
,' ~ont~nuously moyed. It is still another ob~ect of the inven-
29 t~on to provide a mechanism for the gradual automatic re~
. . .
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` ` 1048591
placement of a photoconductor belt used in photocopy machines.
It is still further an object of the invention to provide a --~
convenient method and apparatus for extending the lifetime of
a photoconductor belt in a photocopy machine.
In summary of the above, the present invention provides
a method for effectively extending the lifetime of a photo-
conductor belt used in a photocopy machine comprising the steps
I - of: moving the photoconductor belt around a belt path for the
exposure to an image of an object followed by the development
of the image on a sheet of paper; incrementally replacing the
photoconductor belt with fresh segments to gradually replace
the photoconductor belt around the belt path; and storing a
supply of fresh photoconductor material in connected relation-
ship with the photoconductor belt for movement therewith around ~;
; the belt path and wherein the incremental replacing step further
includes the step of: removing the incremental segments from
the supply of fresh photoconductor material ^ I
1 The above method may be carried out by a photoconductor
j belt assembly for a photocopy machine comprising: a photoconductor
3 20 belt shaped to fit around a photoconductor belt path and adapted
to move along the path in a photocopy machine, the photoconductor
belt having a replacement segment to form a belt length in excess
of the path length to enable a replacement of used photoconductor
belt segments; a photoconductor belt cartridge connected to the
I photoconductor belt and mounted to move therewith along the belt
$ path, the cartridge having a photoconductor supply for the
replacement segment of the photoconductor belt and having a
photoconductor storage element to store used belt portions; the
cartridge being relatively shaped to enable continuous motion of
i 30 the photoconductor along the belt path.
I' ~ .. .
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:~ ` lV~8S91
: Brlef Descrl~tion of Drawln~s
- These and other advantages and objects of the inv~ntion ~ '-
,~, can be understood from the following detailed description of
, a preferred embodLment which is described in conjunction with
.
the drawings wherein
Fig. 1 is a side schematic and partial section view of ~-
-. a photocopy machine of the photoconductor belt type in accordance ,
i ' with the invention; ' ~:
,, Fig. 2 is a perspective partially broken away view of
a roller and photoconductor assembly in accordance with the
invention; ~ -
~: Fig. 3 is a partial side view taken parallel along the
axis of rotation of a roller employed in the roller assembly
; shown in Fig. 2:
Fig. 4 is a section view of a roller and its recess
, with a cartridge of a photoconductor belt located in the recess
iiJ for sequential rotational positions of the roller; ,
Fig. 5 is a partial section view of a roller taken
along the line 5-5 in Fig. 3; ~:
Fig. 6 is a top plan view of a portion of the photo-
conductor belt and cartridge shown in Fig. 2;
~
. -
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~ 1~)48S91
; Fig. 7 is ~n end view in eleyation of the photocon-
ductor belt and cartridge shown in Fig. 67
Fig. 8 is a side view o~ the photoconductor belt and
cartridge as shown in Fig. 7;
Fig. 9 ~s a section ~iew of the photoconductor belt
cartridge as taken along the line 9-9 in Fig. 7; and
Fig. 10 is an enlarged section view of the photocon-
ductor belt cartridge taken along the line 10-10 in Fig. 8.
Detailed Description of Embodiment
~it~ reference to Figs. 1 and 2, a photocopy machine
20 is illustrated with a photoconductor belt 22 mounted for move-
,m,ent along the direction of arrow 23 around a roller assembl~ 24
which æfines a belt path 26.
' Photocopy machine 20 employs various well-known oper- ~ '
a,t~ng components which are schematically illustrated. Thus,
! around belt path 26 are a photoconductor charging device 28
`I located just ahead of a generally flat photoconductor exposure
section 30 where an optical lens system 33 forms a latent image '~
o an object ~not shown).
Exposure of the flat photoconductor section 30 is
obtained with illumination from a high intensity flash source ,
(not shownl. Flash sources and their associated flash initiat- ' -
ing circuitry are generally well-known in the art and, there-
~ fore not ~llustrated. Upon exposure of the photoconductor belt
j 22 at a flat region 30, a latent image of the object is formed
and de~eloped b~ the applicat~on of toner particles from a
suppl~ 32 with a magnetic brush 34. The toner particles then
a~e transferred to a sheet of paper 36,at a transfer station
37, ~ ~a~er ~eed $tat~on 38 provides sheets 36 one at a time
~,ro,m, a ~ta,ck 40 for contact w~th the toner particle covered
~hotoconductor 22, '
After transfer of the toner image onto a sheet of
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1~48591 ;
paper 36, the latt~r is se~arated ~rom the photoconductor belt
22 and adyances past a heat source 42 whic~ ~uses the toner parti-
cles into the sheet o~ paper. A charge ellminator 44 in the form
o~ a light source is provided to expose the entire photoconductor
belt 22 and facilitate subsequent toner removal with a brush 46
and yacuum toner remover 48. After passing of tlle belt cleaner
46, the photoconductor belt 22 may be again used for making a
cop~ of an object. The actuation of the various components are
properly timed with suitable switches operated in a sequence
needed to complete a copy cycle. The circuitry and switches
~or such timing are also known in the art. A motor and drive
~echanism for moving the photoconductor belt 22 around the
~oller assembly 24 are also known and, therefore,,have been delet-
ed for clarity of the drawings.
The roller assembly 24 is shown formed of three rollers
50.1, 50.2 and 50,3 ~rranged in a generally triangular fashion
~lt~ough dif~erent roller arrangements may be accommodated depend-
~n~ upon the type of photocopying machine being built. The roller
assembly 24 is supported by a suitable frame which was deleted
~ . . .
" 20 for clar~ty of the drawings. Each roller 50 rotates about an
ax~s and shaft 52 which are parallel for all rollers 50. Roller
' 50,3 is shown spring loaded by a spring 53 to maintain tension
on photoconductor belt 22 and impart so,me resiliency to the
roller assembly.
The photoconductor belt 22 carries a replacement seg-
~en~ located in a cartridge 54 which moves with belt 22 around
" ~cllers 50 and thus the entixe belt path 26. One end o~ the
p,hotoconductor belt 22 is connected to a supply reel 56 in cart-
~id~e 54. Supply reel 56 carries a rolled up replacement segment
58 ~ee ~ig, 91 of the photoconductor belt 22. The other end
o~ ~he photoconductor belt is connected to a take up reel 60
~n c~tr~dge 54, The take~up reel 60 serves to store used seg-
. '
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1~48591
,~ ment of photoconductor material. The fresh and used segments
o~ the photoconductor belt are'passed throu~h approPriate slits
62r 64 Csee also Fi~. 9) ln the cartridge 54. A slit cl~sure
, ele~ent 66 Csee also Fig. 9) is provided to inhibit toner parti-
;` cles ~rom entering the inside of caxtridge 54.
The cartridge 54 is ~ormed of a generally light-weight
- ~m~aterial, such as plastic, so that the photoconductor belt 22
y support the cartri,dge 54 and its contents without undue or
operationally signi~icant physical distortions of the photo-
10 conductor produced by excessive tensions, bends or flexure
:
~- proble~s.
,,- The photoconductor belt 22 and its attached cartridge
~1 54 ~qr~ a unified assembly which is replaced in its entirety
" when the photoconductor belt has been used. - '
~, Since the cartridge 54 is located on the inside of
,~ the photoconductor belt path 66, the passage of the cartridge over " ,
~i, the rollers 50 is accomplished wlth a cartridge receiving recess
''J.'l -70 i,n each of the rollers 50. T~e cartridge position along belt
path 26 is selected ~n such manner that as the cartridge 54 app-
,roaches a roller 50, a synchronized meshing with the roller
,; rece~ving recess 70 for entry thereof is established. In this
anner the photoconductor belt 22 may be continuously moved
', around the path 26 while the belt is kept sufficiently taut.,
, Each recess 70 is normally covered with a pair of
'' doors 72-72' that may be locked into a closed position with a
loc~ing mechanism 73 located at each axial end of a roller 50.
' The covers 72 are curved to provide a continuous peripheral sur-
$ace ~th the cylindrical surfaces 75 of rollers 50.
'";j The mounting of the photoconductor belt and cartridge
3~ as~e~bl~ is establis~ed w~tn precise synchrQnization relative
, t~ t~ roller receisses 70 so that the cartridge 54 will properly
,' enter a recess 70 during belt motion. In addition, the rotations
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- 1~4859~
of the rollers 50 are synchronized with each other with a pair
of axially end located timing belts 74-74' spanning the helt path
26. Timiny belts 74 couples to axially end located timing ring
gears 76-76' on each roller 50. The mounting of the photoconductor
~ belt 22 and cartridge 54 with timing belts 74-74' on the roller
; assembly 24 may include a collapsible assembly as shown, for
example, in the art, U. S. Patent to Gardner et al, 3,521,950
~ and those sect.ions thereof dealing with a roller assembly module
.~ as shown in Fig. 1~. Thus a roller 50 may be moved inwardly to
enable one to fit the photoconductor belt around the belt path.
The photoconductor belt 22 and cartridge 54 are locat-
ed between the timing belts 74 as can be seen in the views of
Figs. 2 and 6. The cartridge 54 is attached to the belts 74 with
,: .
an extension bracket 78. Bracket 78 may be attached to timing
belts 74 at different locations by adjusting wing clamps 80.
Such lengthwise adjustment thus enables precise registration
. and proper synchronous arrival of the cartridge 54 relative to
recesses 70. Appropriate alignment indications are provided
on belts 74 to aid the desired registration of cartridge 54
relative to rollers 50 and their recesses 70.
A dçsirable feature of the photoconductor belt assem-
bly in accordance with the invention resides in the ability to
. replace deteriorated photoconductor belt segments in an automatic
continual manner. A belt replacement drive 82 (see Figs. 6, 7
and 8) is mounted on the cartridge 54 and coupled to the take-
: up reel 60 to cause an incremental rotation thereof with each
complete cycle of the photoconductor belt 22 about path 26.
The drive 82 is formed with a stationary pin 84 mount-
ed to a frame ~not shown) near the path along which the cartridge
54 travels. The stationary pin 84 engages a Geneva mechanism 86
on caxtxidge 54 formed of a maltese cross shaped actuator 88 hav-
~ng four corner located slots 90 arranged to engage pin 84, The
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1~4~591
, actuator 88 is connected to ~ pinion 92 which is coupled throu~h
reduction gearing $ormed of a spiral gear 94 to the shaft o~ take-
', up reel 60. -,'
- Hence, as the photoconductor belt 22 ~s driven around
,' the belt path 26~ pin 84 is caused to eng~ge a slot 90, thus
causing a one-quarter turn of the actuator 88 and its connected
', pinion 92, The speed reduction obtained between pinion 92 and
, spiral gear 94 reduces the rot~tional drive of the take-up reel
., .
- 60 to a sm~ raction of an inch.
~- 10 The incremental advance of photoconductor belt replace- '
"~ ,m,ents by the take-up reel 60 is selected on the basis of the number
f, ~ualit~ copies that can be made with any one segment of the
photoconductor belt 22. For example, if one can make five thousand
~, qualit~ copies which are ten inches long, as measured along path
"," 26, then after five thousand cycles ten inches of photoconductor
material must have been replaced. This would require at least
,1
;~.!' 0'~ 002" Ctwo thousandth's of an inch) effective take-up belt or
'l ,replacement motion ~y take-up reel 60 for each cycle. If actuator ' -
88 under~oes about o,ne-quarter inch rotational motion, a speed
x~duction of about one hundred twenty-five to one ~125:1) is need-
,~ ed to establish a precise .002" incremental belt replacement.
~hen an advance or replacement of the order of .005" for each
Cycle ~s néeded, the reduction ratto becomes of the order of
:'!
'l fifty to one ~S0:11.
: , Actually, the-incremental replacement introduced by
t~e ~ctuation of th~ Gene~a,mechanlsm 86 will v~ry depending upon
the effective xadius of the take~up reel 60. Thus initially the
~ncxemental adyance may be so~ewhat less than .002" while the '
'' a,dva,nce ~ ncrease as,m,ore photoconductor belt iswound onto
t,a,ke-up reel 60.
,; The total amount o~ photoconductor belt material that
' can be $tored by cartridge 54 determines the effective lifetime
cb~ - 13 -
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48S91
;, of the entire belt assembl~. Since replacement is carried out
on a continual basis~ i.e. by small increments measured in frac-
tionS of an inch~ the quality of the copies w~ll be generally
çonsistent. The incremental advance may be varied depending
. ~
~pon the t~pe o~ photoconductor m~teri~l and the acceptable level
'
Qf ~u~lity. The range o~ incremental advances may vary, by
selecting the reduction ratio, or by altering the diameter of
the take-up reel 60 or by producing an incremental advance for
eyery two or several number of cycles or combinations thereof.
Generally the incremental replacement is selected small in compari-
s,on with the length of the image or the length of the photo-
cQnductor belt path to enable the gradual photoconductor belt
replacement.
The incremental advance or replacement of the photo-
~onductor is particularly advantageous in distributing physical
l~ading such as may be caused at bending points. Thus, the
entry and departure of the cartridge 54 relative to a roller
recess 70 may'involve shape changes whose damaging effects on
the photoconductor tend to be reduced by its,continual replace-
,ment,
The incremental replacement of the photoconductor
i~s preferabl~ of such small amount that the initial resulting
inc,rease in tension ~s neglig~ble. The small additional take-
up tends to be d~stributed over the entire photoconductor belt
22 as the latter with its cartridge 54 is moved through a copy-
~ng c~cle over the various rollers 50.
The ~uantity of fresh photoconductor belt material on
the su~ply reel 56 is selec'ted to achieve a desired total copy-
~,n~ capability ,~or the belt and cartridge assembly. The maxi-
mum sto~age o~ photoconductor belt material within the cartridge
54 ~ust be limited to mainta~n the cartridge s~ze to enable its
pasSage past rollers SO.
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1048591
As shown in Fig. 9, the cartridge 54 includes a pair
of output idlers 100~ 100' which are located adjacent slits 62,
, 64 ~espectivel~, Idlers 100 facllitate the transfer of photo-
conductor belt 22 out of and into the cartridge recess 102.
The supply reel 56 is mounted wtth a friction disc 104 (see
Flg. 10) adjacent an ax~al end to inhi~it free rotation of supply
~eel 56 and provide a minimum amount o~ tension in the photo-
conductor belt 22. Other restraining elements could be used
such as a spring loading of supply reel 56. The rotations of
Supply reel 56 and take-up reel 60 are in the directions indicat-
~^ ... .
ed b~ arrows 106-106'.
The arrival of the cartridge 54 at any one of rollers
50 is accompanied by an opening of doors 72. The respective
mechanisms for accomplishing the insertion of the cartridge 54
~nto a recess may be conveniently exjlained with reference to
' Figs. 2, 3, 4 and 5. The timing belts 74-74' are each provided
with cams 110~110' respectively formed of outwardly projecting
, , ~stud~s 112 sized to engage locking mechanisms 73. Each locking
, ~echan~,sm 73 is formed of an annular lever segment 114 extend-
,~, 20 ing radially above the peripheral surface 75 of rollers 50 at '
', axial ends thereof.
; ~ As shown in Fig. 5, the annular lever segments 114
a,re-provided with an axial bolt extension llS mounted to slide
~t,n the d~rèction of double headed arrow 116 below both doors
~2~72', A spring 118 which has an end 119 anchored to an end
~all 120 of rollers 50 urges each bolt extension into a door
locking posttion a,s shown in solid lines in Fig. 5.
When the cams 110-110' arrive, generally at about the
sa~e time, at roller 50, the front or forward cam studs 112
~ engage annular lever $e~ments 114.114~ and gradually force
t~e~ outwardly as the rollers rotate in the direction of arrow
~22 and t~e ~hotoconductor belt moves clockwise'in the direction
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10~8591
of arrows 23. By the ti~e the cartridye 54 arrives at a recess
70, the lockin~ bolt 115 will ~ay~ been cammed out to the posi-
i tion indicated in dotted lines in Fig. 5, thereby enabling doors 70
to open inwardly.
Both doors 72-~2' are pivotally mounted at pivots 128
and urged in a closed position with springs 130-130' respectively
to preserve the cylindrical shape of roller 50. As the cart-
r~dge 54 arrives, it ~orces doors 72 open to their open position
as shown in Fig. 4. When the cartridge 54 has fully entered
-~ 10 recess 70, a pair of studs 132 arrest further inward movement.
Studs 132 are mounted on roller end walls 120-120' and extend
axially into the cartridge recess 70 for a distance sufficient
to seat the bottom wall of cartridge 74. Since, as shown in
Fig. 4, doors 72 swing past studs 132, each door is provided
~ith end located cut-outs 134. These cut-outs are sufficient~y
narrow, aS shown in Fig. S, to prevent affecting the photoconductor
22, Segments 136 of doors 72 are provided with axial extensions
138 which engage the outer wall of rollers 50 to firmly seat
d~ors 72 in their closed position.
The annual extended shape of the lever segments 114
~is provided to assure an unlocking or released position of the
~olt SegmentS 115 throughout the passage of the cartridge 54 past
a roller 50. As shown in Fig. 4, the length of cam 110 or
' number o studs 112 is selected to maintain cam contact from
the time a cartridge enters a recess 70 until the time it has
le~t a recess. As a result, the bolt segment 115 will remain
open until the doors 72 haye been ~eclosed and then slides in
under pressure ~rom springs 118 to lock the doors in their
closed position.
` 30 As shown ln Fig. 4, the entry of cartridge 54 into
~eces~s~ 70 o~ roller 50 is accompanied with a readjustment of
t~ photoconductor belt 22, Thus when cartridge 54 is seated
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.. . . .. ..
1048591
on studs 132, a straight se~ment 140 of belt 22 is ~ormed
between cartridge 54 and th~ ed~e 142 o~ the peripheral wall
~f roller S0. The'photoconductor thus undergoes shape changes
its cartridge is moved past a roller. Since any one belt
section is gradually replaced, ~t will not ~e sub~ected to
excessive stresses over an extended time; hence, any discontin-
uities presented ~n the photoconductor belt, such as when cart-
~idge 54 is mo~ing past a roller 50, can be tolerated.
The operation of the photocopying machine 20 includes
~uitable t~ing controls to preferably expose the photoconductor
belt 22 at the ~ost appropriate time. Thus when the cartridge
54 is in transit between rollers and the closure elements oper-
ati,ve with recesses 70 assure a firm cylindrical surface of
rollers 50, belt 22 has a generally constant tension force and
~i,s ~ree from disturbances to enable the formation of an unblurred '
latent image. In a similar manner, the transfer of the toner
particles ~rom the latent image onto a sheet of paper is timed
to occur when the photoconductor movement is steady.
The operation thus includes a continuous movement of'
the photoconductor belt around the belt path while it is being
gradually replaced by the incremental take-up action of the ,,
take-up roller. The incremental advance may vary in size,
~epending upon the number of rollers, the size of the take-up
Qller and the replacement rate of the photoconductor.
Having thus described a photocopy machine in accordance
ith'the invention, its advantages may be appreciated. A belt
ph~toconductor of a relatively low copy producing capability
per un~t length ma~ be used with flash exposures, yet with a
long over~all effective lifetime. The gradual replacement of
the Rhotoconductor provides a convenient method to assure a
h ~ h ~ualit~ o~ copi,es~
17 -
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