LU81749A1 - TABLE REPROGRAPHY MACHINE - Google Patents

Description

3 1 T 4) QPAND "I) UCHÉ DE LUXEMBOURG D * ^ 0.814

Patent N ° _________________________________ / .________ ^ of ..2 o.ctQbre .... l97.9 ... ÎOTJ Mister Minister ___, ..., iSgj of the National Economy and the Middle Classes

Title issued: __________________________________ fcsÇdfâl Industrial Property Service

_ LUXEMBOURG

Breyet's request for invention I. Request

Mr. HOFFMAN Lionel Bloomfleldf 62o Wishinq Well Road, __________ (1) ... vmiQEE, ..... Ne.w ... jJ.ers.ey .... o.7..4.8.1. / .. ... United States ..... dlMérique., ..... represented ____________ ... pan_.Monsle.! I ": .... Ja.QqMas .... 4.e ... Muys. er ..... acting ..... sn .... guslitë .... de ........................... . @). representative ............................................. .................................................. .................................................. .................................................. ................................

drop off ........ this .. from.ux .... o. October .... l9.oo .... seventy-nine .____________________ es). at ....... ..... 15 .......... hours, at the Ministry of the Economy. Nationale et des Classes Moyennes, in Luxembourg: 1. this request for obtaining a patent for an invention concerning: ... ". Machina .... ^ ..... table", ___________________________________ (4) declares, assuming responsibility for this declaration, that the inventor (s) is (are): ... Mister ..... HQEEM2Uâ .... Lio.nel ... BlQ.omf.i.eld ., ....... 62Q ..... Wisbing ..... Well .... BQM #______ (5) WYKOFFf New Jersey 07481 / United States of America __________________________________ 2. the delegation of power, dated ------------------------------------------------ ---------------- on __________________________________ 3. description in language £ XânÇ. & i.S.3 ._______________________________ of the invention in two copies; 4. _____________ drawing boards, in two copies; 5. the receipt of the taxes paid to the Luxembourg Registration Office on .............. 2 ..... October ..... 1979 _____________________________________________________________ y ____________________________________...__________________________________________________________ claims for the above patent application the priority of one (or more) application (s). · (6) ________________ patent __________________________________________ filed® in (7) United States of America ___________ on October 2, 1978 (No. 947 873) ___________________________________________________________________________________________________ on behalf of 11 inventor .................................................. .................................................. .................................................. ................ (¾ elect domicile for him / her and, if designated, for his / her representative, in Luxembourg _______________________________ ..... 3.5 / ...... bd * .....- Royal ......................................... ............... .................................................. .................................................. .................................................. (io): * requests the grant of a patent for the invention for the subject described and represented in the abovementioned appendices, - with postponement of this grant to ..... // ......... .............. ........ months.

Π. Deposit Minutes

The above application for a patent for invention has been filed with the Ministry of National Economy and the Middle Classes, Industrial Property Service in Luxembourg, dated: October 2, 1979

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........... · .. Pr. The Minister.

at ............ 15 ......... hours / \ of the National Economy and the Middle Classes,.

f ': P ·' £; (y 03 G- \ j G.

! A 68007 V ............ V · - - D. 5o.814

. ^ CLAIM OF PRIORITY

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In UNITED STATES OF AMERICA From October 2, 1978 Description Brief filed in support of a request for

PATENT

at

Luxembourg

i on behalf of: Lionel Bloomfield HOFFMAN

i for: "Table reprographic machine".

i • V- *

The present invention relates generally to electrophotographic reprographic machines, and more particularly relates to a reprographic table machine on ordinary paper, of small dimensions and which consumes a minimum of energy.

Electrophotographic reprographic machines on plain paper are well known devices which reproduce images of original documents on ordinary paper. In general, these machines include a reusable photoreceptor 10 consisting of a conductive support coated with a photoconductive material, a reserve of copy sheets, made of plain paper, and several processing stations for the photoconductor and the copy sheets. During a series of reprographic operations, the photoreceptor is 1 ^ uniformly charged, then it is exposed to an illuminated original document. The regions of the photoreceptor which receive the image of the symbols carried by the original document retain their charges while the regions which receive the light are dissipated. A latent electrostatic image is thus formed on the photoconductive coating of the photoreceptor. Next, the latent image is developed by contacting the photoreceptor with developer particles which are electrically attracted and which adhere to the charged regions of the photoconductive coating to form the latent image. The developed image is then transferred to the copy sheet, on which the developer is melted so as to fix the image there.

Older models of plain paper copiers were, in general, cumbersome, expensive and complex machines which constantly consumed energy even in idle or standby mode. These machines were cumbersome because they included a relatively large ray drum supporting a photoreceptor, or a strip type photoreceptor driven along a very long path passing through the processing stations. These ’machines are not practical for some users who only have a limited office area or whose reprography needs are modest.

Attempts have therefore been made to reduce

V

i * 2 dimensions of copiers on plain paper and to simplify their operation in order to meet the economic and congestion conditions of users who desire copies on plain paper in relatively reduced volume. U.S. Patents 4,012,138, 4,017,170, 3,819,261 and 3,606,532 illustrate these attempts. However, the devices described in these patents have one or more drawbacks, including the use of a * photoreceptor supported by a drum which occupies a relatively large volume OJ, a mobile optical device which can be expensive and of complex operation, separate development and cleaning stations and a fusion device which constantly consumes energy even if no copy is made. These attempts to reduce dimensions have often led to devices which are difficult to maintain since access to the elements essential for their maintenance may be hampered by other closely spaced elements. There is therefore a need for a compact machine comprising elements which are close to each other and of easy access.

A number of reprographic machines have a strip type photoreceptor. These photoreceptors naturally pass over one side of the pulley or roller which supports the strip, producing misalignment of the photoreceptor. A solution to this problem has been found by using a drive by teeth and support rollers. But solutions of this kind are expensive so that the need remains for a relatively simple and inexpensive tape alignment device.

An object of the invention is therefore to produce a table reprography machine on ordinary paper, of small dimensions; a reprographic machine that consumes a minimum amount of energy; a reprographic machine that only consumes energy when it actually makes copies; a machine which has a relatively short photoreceptor strip; a machine whose photoreceptor strip is supported between two rollers of different dimensions; a machine whose axes of the rollers are inclined so as to drive the photoreceptor ·> 3 t in one direction; and a machine which comprises a Z-shaped optical path and of which practically all the processing stations and the photoreceptor are situated between the ends of the optical path.

Another object of the invention is to provide a control device intended to rotate the photoreceptor strip in two cycles for each desired copy of an original and to control the sequential operation of the processing stations during each cycle.

Yet another object of the invention is to mount a certain number of treatment stations on an articulated upper support assembly making it possible to move these stations by rotation and thus allow access to the rest of the machine.

Yet another object of the invention is to provide a removable lower support assembly for supplying copy paper for accessing the machine.

Another object of the invention is to provide a common actuating device for tilting the rollers, bringing the developing device into its operating position and supporting the drive roller.

The invention therefore relates to a photoreceptor strip supported by two rollers with different diameters, namely a relatively large diameter drive roller and another relatively small diameter roller. The photoreceptive strip therefore has a shape which resembles a drop. The assembly is enclosed in a rectangular case - the large diameter roller at a higher angle and the smaller diameter roller offset diagonally.

"According to the invention, the photoreceptive strip is kept in correct alignment by intentionally arranging the axes of the two rollers so that they make an angle between them. This arrangement of the rollers causes the photoreceptive strip to tend to move laterally to one side when the rollers rotate. In this embodiment, the necessary angular offset is obtained by tilting the smaller roller. A flange is arranged at the end of the larger roller towards which the strip tends to This flange prevents the strip from coming out of the rollers and therefore keeps it in * * h correct alignment with the other treatment stations.

Several processing stations and other operating elements are arranged around the outer surface of the photoreceptor strip. A loading station and a development station are arranged near the largest roller.

A transfer station and a copy sheet feeder are located near the smallest roller.

Erasing and discharging stations are arranged between "the smallest roller and the largest, juxtaposed on the transfer station and the sheet feeder", for copying.

According to the invention, a reciprocating carriage exposes a document by scanning in an exposure station which comprises an exposure slot situated in the upper part of the housing, below the carriage. A Z-shaped optical path transmits an image of the analyzed document from the exposure slit to an imaging station located between the load and development stations. Most of the processing stations and other essential devices 20 are arranged between the two ends of the Z-shaped optical path, thus contributing to the reduction of the overall dimensions of the machine according to the invention.

The machine according to the invention also comprises an articulated upper support assembly which supports a certain number of treatment stations. More particularly, the upper support assembly includes a group of incandescent erasure lamps, a discharge or neutralization station, the trolley, the exposure station comprising the ex-i position slot and the lighting lamps. , the optical assembly (two inclined mirrors between which a lens is arranged) and the charging station. The upper support assembly is positioned in the upper part of the housing which contains the machine. The assembly is fixed to the housing by a hinge along the width of the housing, which allows it to be lifted by 33 making it rotate. This type of mounting allows easy access to the rest of the reprography machine, located below the upper support assembly.

The invention also relates to a lower support assembly which supports a number of essential elements i 7 5 t arranged under the photoreceptor. The lower support assembly supports a copy sheet feeder tray on which a stack of sheets is stored for making copies. The lower support assembly also supports two standby rollers and a transfer station. The waiting rollers receive a copy sheet which is brought into their gap and retain it until the desired moment when they advance it by contact and align it correctly with the image developed on the photoreceptive strip. The copy sheet reserve tray can be * removed and inserted by sliding in the lower support assembly to place copy sheets therein or change their dimensions. In addition, the lower support assembly is completely removable to allow access to the lower face 15 of the photoreceptor and of the development device. The lower support assembly is arranged to be removable from the machine in the direction opposite to that of the movement of the copy sheets. This arrangement is particularly advantageous for clearing the paper jams 20 which may occur because the removal of this assembly tends to release or unfold copy sheets, thus avoiding damage to fragile elements such as the transfer station and the photoreceptor tape.

The lower support assembly is further arranged so as to actuate a certain number of essential elements or essential positions by bringing them in or out of their respective correct position. A combination of mechanical linkages and cams couples the largest roller and the development station (magnetic broom development device) with the lower assembly. When the latter is extracted, the free roller is moved towards the drive roller, so that the photoreceptive strip is relaxed. In addition, the magnetic brush is moved away from its operating position, that is to say in alignment with the photoreceptive strip. This strip can thus be replaced and the magnetic brush is accessible for its maintenance or the replacement of the developer, When the lower assembly is completely introduced, the crankshafts and the cams work in such a way that the small roller ♦ 6 t) moves to its normal operating position, thus stretching the photoconductive strip and arranging the axis of the largest roller so that it makes an angle with that of the smallest roller. In addition, the magneti-5 brush is brought closer to its operating position, in alignment with the photoreceptive strip.

The lower support assembly also supports the larger roller which is mainly cantilevered o in the housing. A baluster mounted on the lower support assembly 10 engages the unsupported end of the largest roller to provide additional support and its alignment as well as that of the photoreceptor with the other processing stations and essential elements.

No energy is required to keep the machine 15 in standby mode. In addition, the development and fixing stations according to the invention jointly contribute to the relatively low energy consumption for copies in active operation. To this end, the development station includes a magneti-20 development device that allows the use of any suitable developer, to be fixed by pressure. The development station also operates as a cleaning station to remove the non-transferred developer from the photoreceptor strip, thereby eliminating the need for a separate cleaning apparatus which would normally include a vacuum device. The fixing station has two pressure fixing rollers which receive a copy sheet with a developed image *. The pressure exerted on the copy sheet and developer by the rollers is sufficient to permanently fix the developer on the copy sheet, eliminating the need for an electrically heated fuser.

The control device according to the invention comprises a group of cams which actuates a corresponding group of 35 control switches which, in their turn, selectively excite certain treatment stations and other essential elements. With each copy, the control device causes the photoreceptor strip to drive over two cycles. At the start of the first cycle, the largest roller + 7 is engaged with a main motor, the magnetic broom starts to rotate and the carriage moves. moves from a rest position along the exposure slot. Simultaneously with the start of the first cycle, the control device 5 switches on the light station lamp and the charging station. During the first round, the copy sheet is fed into the waiting rollers. At a predetermined time, the controller actuates the holding rollers so that the sodb copy sheet brought into contact and aligned with the developed image, and the transfer of the developer onto the sheet begins. When the leading edge of the image on the photoreceptor passes over the smallest roller, the copy sheet is separated from the photoreceptor and is guided into the gap of the fixing rollers 15 by pressing * The leading edge of the latent image residual with developer not transferred then passes through the erasure lamps and the discharge station which are switched on during the entire reprography operation.

When the photoreceptor begins its second turn, the carriage starts to return to its initial position. The control device removes power from the corona charging device and the lighting lamps. This is necessary to remove the non-transferred developer from the photoreceptor. When the photoreceptor passes the magnetic brush during the second cycle, the non-transferred developer particles are attracted to the brush because almost all of the electrostatic charge of the developer has been neutralized at the discharge station. The crown effect transfer device is de-energized after a predeter-mined period during the first cycle so as not to load the imageless parts of the photoreceptor. If only one copy is to be made, the whole machine is de-energized at the end of the second cycle. If multiple copies are to be made, the above series of operations is repeated for each copy until the desired number of copies are made, and the machine is stopped.

Other characteristics and advantages of the invention will become apparent from the description which follows.

In the accompanying drawings, given solely by way of example ♦ 8 in no way limitative: FIG. 1 is a schematic view of the mechanisms of the reprographic machine according to the invention, FIG. 2 is a partial view in elevation of the assembly upper support in its raised position (in solid lines) and in its operating position (in broken lines), FIG. 3a is a partial perspective view of the interior of the machine, showing one side of the magnetic brush 10 the photoreceptive strip , the rollers and the lower support assembly, Figure 3b is a partial perspective view showing the tilting mechanism of the roller, Figure 4 is a view similar to that of Figure 3a but on the other side of the machine, Figure $ a is an elevational view of the tilt mechanism in the operating position, Figure 5b is an elevational view of the tilt mechanism in its released position, Figure 6a is an elevational view showing over there nde photoreceptor stretched in alignment with the magnetic brush corresponding to FIG. 5a, FIG. 6b is an elevation view of the relaxed photoreceptor strip, out of alignment with the magnetic brush, FIG. corresponding to FIG. 5b, the figures 7a to 7f are a series of views showing the retaining cams, Figure 8 is a schematic perspective view of the drive device, parts of which are slightly exaggerated to show the drive relationships among the various elements, Figure 9 is an electrical diagram of the control device of the machine, and FIG. 10 is a diagram illustrating the series of the operations of the machine in single copy and multiple copy operation,

The reprographic machine 10 comprises a rectangular carriage 12 with reciprocating movement above a housing 11.

The carriage 12 comprises a transparent plate 14 on which * 4 9 of the documents to be reproduced are placed face down. The tray 14 is covered by a movable cover 16 with a white surface in contact with the tray 14. The cover 16 is fixed to one side of the carriage 12. In the present embodiment, the cover 16 is made of a material relatively flexible fixed by a hinge under one of the longest sides of the carriage 12. The cover 16 carries a handle 17 opposite its hinge. An operator can manipulate the handle 17 to raise or lower the cover 16 in order to place or remove documents on the tray 14.

»Figure 1 shows the carriage 12 in its extreme right or rest position. During a copy cycle, the carriage moves to the left by a predetermined distance, long enough to allow machine 10 to make copies of 355mm long documents. A lighting station, generally designated by 20, is arranged under the carriage. This station has a relatively narrow transparent window 27 on the upper surface 19 of the housing 11. The window 27 is arranged along the width of the upper face 19. A light source is arranged below the window. This source consists of two lamps 28 axially aligned and partially surrounded by a shaped reflector 30 which directs the light from the lamps 28 to the window 27. When the carriage 12 moves from the right to the left, a document that it carries over the window 27 and is lit by the light coming from the lamps 28. In other words, the document is exposed by scanning on the lighting station 20.

* An image of the document is transmitted to the photoreceptive tape 30 k to an image forming station generally designated by 35. The image is transmitted along a Z-shaped path by an optical assembly 21 comprising inclined mirrors 22 , 26 and a lens 24. The mirror 22 receives an image of the lit document when it passes over the window 27. The mirror 22 reflects the light towards the converging lens 2k. The latter is focused on the second inclined mirror 26 which, in its own way, reflects the image focused on a portion of the ko strip at the image forming station 35 "The photoreceptive band 40 moves * 10 at the image formation at a predetermined speed, in synchronism with the movement of the carriage 12 of the light station 20, The motive force which rotates the drive roller 42 is supplied by a main motor 5 62 and through a suitable transmission device comprising a chain 61 (partially shown) The chain 61 also drives other elements, including the "magnetic brush 37, the carriage 12 and the rollers 46, 48 of advance and standby. Control cams 64 and the fixing rollers 54 are driven by a second motor 63.

As indicated above, the photoreceptive strip 40 is supported below the Z-shaped optical device 21 by a drive roller 42 of relatively large diameter and a free roller 44 of relatively small diameter. The rollers 42, 44 are offset diagonally with respect to each other and their respective axes are arranged angularly with respect to each other, that is to say that they are inclined and not parallel . Due to the relative difference in dimensions between the two rollers 42, 44, the photoreceptive strip 40 follows a shape similar to that of a drop. The strip 40 itself carries a photosensitive upper layer, preferably of zinc oxide (ZnO) deposited on a conductive support, preferably in metallized polyester film, for example a Mylar brand film with a base of 'aluminum.

A number of elements of the machine 10 are available around the periphery of the photoreceptive strip 4θ.

In particular, a two-wire crown effect charging unit 32 is arranged on the photoreceptive strip 40 with an offset of approximately 30 ° in a clockwise direction with respect to the vertical passing through the center of the roller 42. The charging unit 32 applies a uniform electrostatic charge to the zinc oxide layer of the photoreceptor 40. The drive roller 42 rotates clockwise so that the surface uniformly charged with the photoconductive strip passes through the charging unit 32 to the image forming station 35 · A blade-shaped shutter 34 is associated with the image forming station. This flap 34 is movable in the machine 10 to be manipulated by an operator who adjusts the amount of light directed towards the photoreceptor 40 at the image forming station 35 # According to the well-known photo-5 copying technique, the the photoreceptive strip 10 which receives light are electrically discharged, thus leaving a latent electrostatic image (undeveloped) which corresponds to the symbols (printed parts) of the document to be reproduced.

When the drive roller 42 rotates, the latent image on the photoreceptive strip 40 passes through a development station 36 disposed at 90 ° with respect to the vertical passing through the axis of the roller 42. Development 36 includes a hopper 39 which contains a developer reserve. The present embodiment of the invention uses a developer with two components, namely iron filings and a marking material which can be fixed by pressure; but a one-component developer might also be suitable. These developers and development stations are well known and need only be described to the extent of their function in the overall reprography process which takes place in the machine 10. It suffices to note that the magnetic brush Turning 37 takes the developer from the hopper 39 and brings it into contact with the photoreceptor 25 40. The latent image regions or the regions charged with the photoreceptor electrostatically attract and retain the particles of developer, which develops the latent image.

"The developed image leaves the development station 36 30 and moves to the transfer station 50 in which there is a transfer charge device 51 with a two-wire crown effect. In time relationship with the arrival of the image developed at the charging device 51, a copy sheet arrives at the transfer station 50. The copy sheet comes from a reserve of sheets 45 stored on a removable tray 102. A feed roller 46 drives the sheet upper copy of the reserve '45 * passing through a paper guide 47, and in the interstice of the waiting rollers 48. At a predetermined instant, during the reprography cycle, e 12, the waiting rollers 48 are actuated to advance the copy sheet along the guide 49, in contact with the developed image supported by the photoreceptive bende 40. Due to the electric charge produced by the crown effect transfer apparatus 51, the particles of developer are drawn from the 4θ strip to the has copy sheet on which they adhere slightly.

The copy sheet is separated from the photoreceptive tape 40 by the mutual action of the free roller 44 of small diameter with the relative rigidity of the sheet. In other words, when the photoreceptor passes around the free roll 44, the copy sheet does not follow the strip 40. Its front edge moves away from the strip along a path which is initially tangent to the free roll 44. The copy sheet is finally guided by a paper guide 52 into the gap of the pressure fixing rollers 54.

The pressure fixing rollers 54 consist of two stainless steel rollers which are applied in mutual contact by a spring, with a linear pressure of about 20 ~ 60 kilograms per linear cm. The axes of the pressure rollers 54 are slightly inclined relative to each other so as to keep them in contact. Otherwise, the rollers would tend to deform leaving a gap between them at their interstice. The rollers 54 are rotated so that the speed of the copy sheet therebetween is slightly less than the speed with which it is fed. This is necessary to ensure that the rollers do not prematurely pull the copy sheet from the photoreceptive tape 40, i.e. before the transfer of developer onto the sheet is complete, which would result in an imperfect, scratched copy . Thus, the copy sheet may form a slight curve before being completely driven by the rollers 5. This slight curvature cannot damage the developer image which adheres lightly to the copy sheet. Under the effect of the high pressure exerted on the developer fixable by pressure by the rollers 54, the image is fixed permanently on the copy sheet when it passes between the rollers. fixing 54 to end up in the receiving plate 56; 13

When the developed image has been transferred, a residual latent electrostatic image and of the non-transferred developer remain on the photoreceptor strip 40. When the latter continues its path, it passes through a corona discharge device 5 with a single wire which neutralizes the charge on the non-transferred developer. Next, the strip kb passes under a group of erasing incandescent lamps 60 - (preferably four), The light from the erasing lamps 60 illuminates the strip 40, discharges the image 10 residual latent of this band thus erasing the electrostatic image which remains.

When the photoreceptive strip 40 begins its second cycle, the carriage 12 begins to return from its extreme left position to its extreme right or rest position. During the second cycle, the crown effect charging device 32 and the transfer charging device 51 no longer function. Under the effect of the erasing lamps 60 and the discharge device 58 "the non-transferred developer now adheres • only slightly to the photoreceptive strip 40. 20 When the non-transferred developer passes in front of the magnetic brush 37" this the latter attracts the band 4o. Thus, the magnetic brush 37 fulfills two functions: in the first cycle it develops the latent electrostatic image, and in the second cycle it cleans the developer not transferred from the photoreceptor.

Thus, "after the second cycle, the photoreceptive tape kO is cleaned of the developer and ready to make another copy.

As can easily be seen from FIG. 1, most of the essential elements of the machine 10 are arranged between the ends of the optical path at Z, that is to say between the inclined mirrors 22 and 26. In particular, the photoreceptive strip 40, the charging station 32, the development station 36, the device with transfer crown effect 50, the device with discharge crown effect 58 and the collapse lamps 35 are all arranged in a relatively small volume limited vertically by the ends of the path of the optical system, in Z. The shape of the optical path therefore cooperates with the physical position of the essential elements to achieve a reprography machine on ordinary paper 14 of reduced dimensions ”

In addition, the optical device 21 described above considerably reduces the structures which are ordinarily necessary to support the carriage 12 with reciprocating movement. This relatively light structure which supports the carriage 12 is shown in Figure 8, according to which one side of the carriage is supported by a guide rail 80 having upper and lower grooves 81a, 81b. Sliding supports 82 each have two grooves 83a, 10 83b juxtaposed on the grooves 81a, 81b. Balls 84. roll freely in the juxtaposed grooves 81a, 81b and • 83a, 83b. Hinges 85 (one per support) are fixed by one end to one side of the plate 14 and by the other end to the mounting supports. A fixed rail 86 supports the side of the plate 14 opposite the hinge. In the present embodiment, the plate 14 has a length of 419mm and its stroke exceeds the machine 10 by a maximum of 250mm. This relatively small overshoot is obtained by the position of the exposure window 27 away from the ends 20 of the machine, towards the center of its upper part. As indicated above, the Z-shaped optical path makes it possible to locate the window 27 at a distance from the ends of the machine to fulfill its function.

Figure 2 illustrates one of the advantages of the invention, consisting of an upper support assembly. 70. The following elements are mounted on the assembly 70: the carriage 12, the lighting window 27, the Z-shaped optical device 21, the lighting lamps 28 and the reflector 30, the effect device discharge crown 58, the group 30 of effacemert lamps 60, the charge crown effect device 32 and the flap 34. The upper support assembly is articulated on a central frame 90 by a support 71 in the form of an elongated C. The central part of the support 71 is fixed to the underside of the left end of the upper support assembly. The two ends of the support 71 are articulated on the respective vertical parts of the upper support assembly ', and on the central frame 9 °.

A pneumatic support 72 comprising a pneumatic cylinder 73 and an extendable rod 74 is articulated by one end 9 '* 15 on the central frame 90 and by the other end on the upper support assembly "O. When the upper support assembly 70 is raised to give access to the machine 10, the pneumatic support 72 maintains the support assembly 70 in its raised posi-tion shown in FIG. 2. When the upper support assembly 70 is lowered into its position of use, the extendable rod is retracted into the cylinder 73 ·

Most of the other essential elements are mounted inside the central frame 90 of the machine 10. One side 10 of the central frame 90 carries a molded part (not shown) providing a cantilever support for one end of the roller drive 40. The support of the other end of the drive roller 40 will be described later. With the exception of the elements supported by the lower support assembly 100, the other elements are mounted inside the central frame 9 ° in the relative positions indicated in FIG. 1.

FIGS. 5a, 5b, 6a, 6b show that the lower support assembly comprises a removable drawer 104 constituted by two side walls 1G5 "106 of roughly triangular shape, a base plate 107 and an end plate 108. The side walls 105, 106 are fixed to the base plate 107 at a predetermined distance from its edges. Two cam surfaces 95, i? 6 are located between the side walls-lines 105, 106 and the corresponding edges of the base plate 107. The cam surfaces 95, 96 perform a number of functions which will be explained below. after. The drawer 104 can be removed entirely from the machine 10, by grasping and pulling a handle 109 which forms part of the end plate 108.

As indicated above, the drawer 104 supports a certain number of elements which are arranged below the photoconductive strip 40. The crown transfer device 51 is arranged transversely and is supported by the flattened front ends of the side walls 105, 106, Two elongated and opposite slots 110, 111 in the shape of a U are provided, one for each side wall 105, 106, at the rear of the crown effect device 51. The rollers d '48 are supported and positioned • * 4 16 in the slots 110, 111. Springs 112, 113 »one on each side wall 105, 106, pass around the ends of the waiting rollers 48 to hold them one against the other. A drive pinion 114 mounted on one of the 5 rollers, exceeds the spring 112 to engage a clutch CL2 which selectively couples the main motor 60 with the rollers 48 to cause a copy in contact with the image developed on the tape photoconductive 4o.

The drawer 104 supports a paper tray 102. The tray 102 has an angle of approximately 10 ° with the horizontal. Under this angle, the copy sheets in the tray are pressed by their own weight against the front wall 103. The side walls 101a, 101b of the tray 102 have notched upper parts 99a "99b near the front wall 103. These notched parts 99a> 99b are in contact with tabs 115a "115b arranged inside the side walls 105, 106 of the drawer. An opening is provided in the base plate 107 for positioning the plate 102 so that the notches 99a 99 99b match the tabs 115a, 115b. The plate 102 is thus supported at an angle of about 10 °.

The drawer 104 also supports the copy sheet feed rollers 46. Two other U-shaped slots 116a, 116b are provided in the side walls 105, 106 of the drawer. The axes of the feed rollers 46 are arranged in the. transverse direction of the drawer 104 and are supported by the side walls 105,? 06 in the slots ^ 116a, 116b. A pinion 117 is mounted on one end of the axis of the roller 146. A clutch CL3 (not shown) ac-30 selectively couples the toothed wheel 117 with the motor 60 to advance the copy from above the reserve of sheets 45. The tray 102 of copy sheets is positioned under the feed roller 46 so that the top sheet is advanced from the reserve 45 when the clutch 35 CL3 is actuated.

As indicated above, cam surfaces 95, 96 are disposed on the outer edges of the base plate 107. A positioning rod 120 for positioning a free roller, appearing in FIG. 3a, consists of an angled lever 121 articulated by its angle on the wall 130. magnetic broom holder. A roller 122 which rests and which rolls on the cam surface 95 is mounted at one end of the bent lever 121. The other end of the bent lever 121 is pinned on a coupling arm 123 · A bar 124 positioning the free roller is arranged along the width of the machine 10, behind the free roller 44. The upper end of the bar 124 is articulated and sup-10 carried between the interior walls 170, 171 · The lower end of the bar 124 is pinned on the coupling arm 123. A short link 125 is pinned on one end of the bar 124 and its other end is fixed on the axis of the free roller 44. Another short biel-15 lette 126 is also disposed between the other end of the free roller 44 and the corresponding end of the positioning bar 124. Flat springs 127a, 127b, one on each end of the bar 124, bear against the links 125, 126 so as to push them, with rou-20 free water 44, into the direction indicated by arrow 128.

In operation, when the drawer 104 is inserted, the roller 122 rises on the cam surface 95, move the bent lever 121 around its pivot, in the clockwise direction. Under the effect of the rotation of the bent rod 121, the coupling arm 123 is pushed towards the free roller 44. The movement of the arm 123 is transmitted to both sides of the free roller 44 by the positioning bar 124 and the short links 125, 126. Consequently the free roller 44 moves in the direction of the arrow 30 128 so as to tension the photo-receiving strip 40 appropriately and to slightly tilt the axis of the roller with respect to the drive 42. The desired inclination is obtained by mounting the axis of the libi-e roller 44 in 'end' slots of the walls 170, 171, at heights different from each other. It is obvious that there are other ways to achieve the same tilt effect.

The angled lever 121 also has the function of displacing the development device 39 with a magnetic brush in order to bring it into its operating position and take it out with respect to the photoconductive strip 44. FIGS. 6a and 6b show that the developing device 39 is mounted on a sliding plate 140. This plate can coulis-5 ser in horizontal slots of interior walls 130, 131 supporting the magnetic brush. A vertical ledge 141a is directed downward from the sliding plate 140. An elongated flat spring 142a is disposed between the ledge 141a and a base ledge 143a projecting upward 10 on the bottom of the inner wall 14l. Thus, when the drawer 104 is put in place, the bent lever 121 pushes the spring 142a and consequently, the sliding plate 14o towards the photoreceptive strip. The same arrangement of flanges and springs is provided on the other side of the sliding plate 140, as shown in FIG. 3b. When the drawer 104 is out, the flat springs push the sliding plate, and therefore the developing device 39 "opposite the photoreceptive strip 40.

Figures 6a, 6b illustrate another cam effect 20 accomplished by the drawer 1θ4. The curved cam surface 97 is provided on the base plate 107 of the drawer 104. An inclined support lever 133 can pivot at one end on the interior wall 131. The other end of the lever 133 is pushed by the cam J? 7 in a notch 134 of the support 25 at the end 135 of the drive roller 42. The other end of the drive roller 42 is supported in cantilever by a pin 136 which can rotate on the plate 137 constituting another interior wall .

The correct positioning of the copy tray 102 is determined by a holding clip 150, as shown in Figures 7a to 7c. The pinch 150 is mounted so as to be able to rotate on the drawer 104 and it comprises an elastic arm 151 which bears against the side wall 101b of the plate 102. A housing 152 is provided in the side wall-the ale 101b for receiving the elastic arm 151 so that the cam surface 155 passes through the opening 180 of the machine wall and bears against the side of the frame 11, thus preventing any other movement of the plate 102. The operator can feel this resistance and he then knows * 19 that the plate 102 is correctly positioned. The resistance of the arm 151 is easily overcome, so that the tray 102 can be removed to replace its reserve or change the size of the paper.

5 Cams 155 on one side of the drawer 104 allow the operator to partially extract this drawer to an intermediate position when the photoreceptive strip 40 is relaxed (as shown in FIG. 2b) and the magnetic brush is moved away from the band. Figures 7d to 7f mon-10 trent that the cam 155 is pinned on one end of the base plate 107 of the drawer 104. A spring 159 is pressed against the cam 155 to return it outwards or rotate it in clockwise. The lateral frame 11 has an opening 180. When the drawer 15 104 is out, the front edge of the cam 155 is pushed into the opening 180. The curved shape of the front edge allows it to come out of the housing and the drawer 104 is extracted until the angle 161 is pressed into the opening 180, against the frame 11. In this position, the photoreceptive strip 20 40 is relaxed and the magnetic brush is moved away from the drive roller 42. If the operator wishes to completely remove the drawer 104, he can manipulate the front edge of the cam 155 so that its angle 161 turns anti-clockwise out of the opening 180 and the drawer 104 can be easily removed.

The control device 200 shown in FIG. 9 comprises a circuit 201 for supplying the engine and the lamp, a circuit 202 for controlling the clutch, a circuit · 203 for controlling the erasing lamp and a circuit for alimenta-30 tion 204. An AC power outlet can be used to power the machine 10. A fuse F1 is connected between the AC power source and the machine. A safety interlock switch S1 has contacts S1A and S1B which are open when the in-35 appears upper support 70 is raised. The two motors 62-, 63 are supplied by contacts K1-1 and K1-2 of a main relay Kl. The exposure lamps 28 are powered by a switch S2 and a triac tripping circuit 205.

20

A transformer T1 and rectifier bridges B1, B2 at two alternations supply direct current to the rest of the control circuit 200. In particular, the output of rectifier B1 supplies the erasing lamps 60 which are always on during the operation of the machine 10, and also supplies the sources to. high voltage of crown effect devices, B3 »B4 and B5.

The DC high-voltage sources B3, b4 and B5 supply the charging devices 32, 51 "58 and apply a DC voltage to the magnetic brush 37 · A substantial reduction in the size of these DC sources is obtained by the use of a high frequency oscillator circuit 206. The emitters of two transistors Q5 "Q6 are connected in common and their bases are connected to the opposite ends of the primary winding of a hysteresis transformer T2. The secondary winding of the transformer T2 is connected to load transformers T3 "T4, T5 in which the high alternating voltage of the transformer T2 is again transformed and it is rectified by the rectifiers B3" b4 and B5 to obtain DC voltages from -6.5 kilovolts, 5 »5 kilovolts and -5» 5 kilovolts for the charging device 32, the discharging device 58 and the transfer charging device 5 "! ·

A potentiometer P1 delivers the DC voltage of 350 volts 25 for the magnetic brush 37 · Contacts S8 and S9 are arranged between the transformer T2 and the transformers T3, T5 of charge and transfer so as to control the devices with crown load effect 32 and transfer 51 · The crown discharge device 58 operates 30 during the entire operating time of the machine 10.

The other controls of the machine 10 are provided by a clutch circuit 202. The machine 10 comprises four electromagnetic clutches CL1-CL4. The CL1 clutch couples the motor 62 with the main drive chain 61. The paper drive CL2 couples the paper feed roller with the chain 61. Similarly, the clutches CL3 and CL4 i-espectively couple the standby rollers and the drive roller 42 with the drive chain 61. The four clocks 21 CL1-CL4 are represented schematically by windings in the control circuit 202. Each clutch has one or more supply circuits which can energize them in a manner which will be explained in more detail below.

The main relay K is also shown in the form of a winding. As already indicated, the contacts K1-1 and K1-2 of the relay K1 control the motors 62, 63. A third contact K1-3 is a holding contact which keeps the relay K energized as long as it receives a current.

'Relay K can be energized by several different circuits. One of these circuits is constituted by a pulse circuit comprising a transistor Q1 and diodes Dp D10. Another circuit is established by a multiple copy switch S 5 when placed in its MC position. A drive roller control contact S6 and the diode D £ also establish an excitation circuit for the relay K1, as do the standby roller contact S7 and the diode D7. A last circuit is established by the contact S6, by the diode Dp.

A Q3 phototransistor is mounted under the photoreceptive band ko, on one of its sides. The band kO has a relatively narrow notch 8, of a length of about 25mm, near its edge and outside of its image-capable portion. The light emitted by the erasing lamps 60 passes through this notch 8 and meets the phototransistor Q3. When the latter is lit, the transistor Q4 is blocked and de-energizes * the drive roller clutch CLk so that the strip stops. Since the ban-30 of 4θ performs two turns per copy, the effect of transistor Q3 is canceled during the first turn by contact S6 which is closed when the notch 8 passes in front of this transistor. The other transistor Q2 of the clutch circuit 202 fulfills a function similar to that of the contact S6. During a multiple copy operation, the transistor Q2 applies a pulse to the transistor Q4 at the end of the second turn of the strip in order to start the clutch CLk again for the next copy.

As shown in Figure 1, a group of control cams 22 are mounted to rotate to operate a group of control switches 66. The switches in group 66 include contact S2 (exposure lights), contact S4 (copy sheet feed rollers), contact 5 S6 (drive roller), contact S7 (standby rollers), contact S8 (load crown device) and contact S9 ( device with crown transfer effect), the references in parentheses designating the contacts of the machine 10 which are controlled by the corresponding switches. Each cam in the group has an eccentric shape in order to • open and close the contact corresponding to a predetermined instant of the reprography cycle. For a given copy cycle, the group of cams 64 performs one revolution, or 360 °. During this time, the photoreceptive strip 40 performs 1 5 J kills two turns. In the present embodiment, the strip 40 has a length of 457mm for receiving copies of legal length and therefore the strip travels 914mm for a copy. FIG. 10 is a diagram which describes the operation of the control switches 66 and the appearance of the essential events as a function of the degree of rotation of the cams 64 and of the distance traveled by the strip. The rectangles associated with the switches indicate the angular positions of the eccentric cam surfaces of each cam relative to the others.

2 * 5 D FIG. 8 represents the drive device 180 of the machine 10, As already indicated, the machine has two motors, the main motor 62 and the motor 63 of the fixing rollers. The latter drives the fixing rollers 54 by the chain 182 which passes over a toothed rtîae 30 183 for driving the fixing rollers and on a toothed wheel 9 of the motor. The magnetic brush 37 is also driven by the motor 63, by means of the toothed wheel 13 mounted co-axially with the toothed wheel 183 for driving the fixing wheel. The torque of the toothed wheel 3 5 13 is transmitted to the toothed wheel 15 of a magnetic brush by a chain 57 and a free toothed wheel 185 or 6th tension.

The carriage 12 and other elements are driven by the main motor 62. A carriage drive chain 65 passes over two toothed wheels 69a, 69b which are * 23 each arranged near one end of the carriage path.

A stirrup 67 is fixed on the carriage and a drive pin 68 is fixed on the chain 65 and it moves vertically inside the stirrup 67. The toothed wheel 69a 5 of the carriage is mounted coaxially on the shaft of the main motor 62. When the motor 62 is running, the chain 65 is driven on the toothed wheels 69a, 69b. The pin 68 pulls the stirrup 67 (on the carriage 12) with the chain 65. When the pin 68 passes over one of the toothed wheels 69a, 69b * 10 the carriage slows down first then the direction of its movement is reversed , thus producing an alternating movement.

The main chain 61 drives the other elements.

The paper advance rollers 46 are coupled to the chain 61 by spur gears 23, 25 driven by the toothed wheel 1 and the clutch CL2. Likewise, the waiting rollers 48 are coupled to the chain 61 by straight sprockets 31, 33 driven by the toothed wheel 2 and the clutch CL3 · The toothed wheel 4-3 drives the larger drive roller 42 diameter by Cl4 clutch. The cams 20 64 are driven by the toothed wheel 4, and by the intermediary of the reduction gears 3a, 3b. The reduction is such that the cams 64 make one complete revolution for two revolutions of the photoconductive strip 40.

When the print contact S3 is closed, the power supply is applied to the transformer T1, which energizes the erasing lamps 60, the crown cleaning device 58 and causes the application of the voltage. continuous from -350 volts to the magnetic brush 37 · In the clutch control circuit 202, the main clutch 30 CL1 is energized. In addition, the RC circuit comprising the resistor R7 and the capacitor C10 unlocks the transistor Q1 for approximately 400 milliseconds, that is to say until the capacitor C10 charges to its capacity. When the transistor Q1 is turned on, power is applied to the main relay K1 by the diodes D9 and D10. As a result, the three contacts of the relay K1 close, so that the contact K1-1 applies the power to the pi-incipai motor 62, the contact K1-2 applies the power 24 to the motor 63 and the contact K1- 3 maintains the supply of transformer T1. The drive roller CL.4 is also energized by the transistor Q1 and the - diodes D11, D10. Thus, the motor 62 is supplied with power, the carriage begins its race towards and above the lighting zone and the photoreceptive strip 4θ rotates as well as the cams 64.

When the cams 64 have rotated by 6 °, which corresponds to about 12mm of travel of the strip 40, the contact S2 closes and the exposure lamps 28 are on.

As indicated above, the transistor Q1 is blocked when the capacitor C10 is fully charged. Consequently, the cam-operated contact for belt control S6 changes position for 3 ° of rotation 15 before CIO is completely discharged in order to offer another continuous supply circuit to the main relay K1 and to clutch CL4 of the drive roller and hand, thus keeping the movement of the strip 40 along its trajectory.

20 A copy paper contact S4 changes position by 10 °, activating the paper advance clutch CL2. The copy paper feed rollers begin to rotate and advance the top copy sheet into the gap of the idle stand rollers 48. Contact 25 S4 opens at 38 °, leaving a slightly curved copy sheet between the feed roller 46 and the intersection of the standby rollers 48.

At 21 °, the contact S8 changes position and supplies the crown effect charging device 32 by the continuous power source at -6.5 kilovolts. Therefore, when the photoreceptive strip 40 passes under the charging device 32, the photosensitive layer of zinc oxide is uniformly charged. As explained above, the image of the document passing through the exposure slot 27 is projected onto the photoconductor 40 loaded in the image forming station 34. The regions of the web 40 which receive light are discharged, which forms a latent electrostatic image. When the image passes in front of the magnetic brush 37 "the developer particles 39 are * 25

T

attached and adhered to the electrostatic image which becomes visible, or developed.

; When the developed image is brought to the transfer station and the cams have turned 100 °, the contact 5 S7 for controlling the standby rollers excites the corresponding CL3 clutch. The copy sheet which has been introduced into the gap of the waiting rollers 48 is driven by the latter, in synchronism with the developed image, so that the image and the copy sheet reach, and pass through the transfer station 50, aligned. When * the image and the copy sheet approach the transfer station 50, the contact S9 for controlling the crown transfer device closes (116 °) thus connecting the crown transfer device 51 to the source 15 continuous supply of -5.5 kilovolts. At the transfer station 50, the developer particles are attracted and adhere to the copy sheet which continues to move in the gap of the fixing rollers 54. Under the effect of the pressure of these rollers, the developer is 20 permanently attached to the copy sheet which is then deposited in the receiving tray 56.

When the cams 64 rotate 165 °, 180 ° and 185 ° respectively, the corresponding control contacts S8, S2 and S6 open, which stops the charging device 22 and the exposure lamps 28, thereby interrupting the power supply circuit of relay K1 by contact S6. The main relay K1 is maintained by another circuit established by the contact S7, that is to say the clutch roller control contact.

The clutch CL4 of the drive roller is held by the transistors Q3, Q4. It should be remembered that the transistor Q3 is a photo transis you ’which blocks the transistor Q4 (and which therefore stops the drive roller 42) when it receives light. This occurs when the notch 8 of the photoconductive strip passes over the transistor Q3. At the end of the first cycle of rotation of the band 40, the effect of the transistor Q3 is canceled by the control contact S6.

This contact S6 maintains xm the CL4 clutch supply circuit for 185 °, which is enough for the notch 2 6 * 8 to have completely exceeded the transistor Q3 · Consequently, at the start of the second cycle of the band 40, the transistor Q3 is no longer lit and the drive roller 42 continues to rotate, the carriage 12 starting its return stroke towards 5 its rest position. During the second turn of the photoreceptive strip 40, the transfer operation is completed and the transfer control contact S9 opens so that the transfer device 50 is no longer supplied.

5 As indicated above, the corona discharge device 58 and the erasing lamps 60 are energized for substantially the entire duration of the two cycles of the strip 40. The leading edge of the latent image residual, carrying non-transferred developer, passes under the discharge device 58 which neutralizes the charges which have been produced in the developer by the transfer device 51. The erasing lamps 60 illuminate the photoreceptor to discharge the latent electrostatic image residual. With the developer remaining neutralized and the photoreceptor discharged, there remains only a slight or zero force to hold the developer on the photoreceptive strip 40 · Consequently, when the strip passes in front of the magnetic brush 37 during the second cycle, this brush attracts the developer of the tape, which is thus cleaned.

The strip · 40 continues to rotate until the notch 25 8 passes over the phototrsnsistor Q3. The light coming from the erasing lamps 60 passes through the notch 8 towards the. phototransistor Q3 which blocks transistor Q4. The blocking of the transistor Q4 removes the supply circuit of the clutch CL4 which interrupts the drive of the roller 42. Subsequently, the contact S7 opens which interrupts the supply of the clutch CL3 of the rollers d 'wait, as well as the main relay K1. The three contacts of the relay K1 open, so that the contact K1-1 stops the main motor 62, the contact K1-2 stops the motor 63 and the contact K1-3 cuts off the supply of the transformer T1. Under these conditions, the DC voltage supplied by the bridge B1 is suppressed, so that the erasing lamps 60 and the cleaning device 58 are interrupted. Similarly * 27, the DC voltage of the rectifier B2 is interrupted, which opens the main clutch CL1. The latter is both a clutch and a brake combined, so that all the machine elements which are driven by this motor 62 5 are braked to a standstill.

When multiple copies of the same document are to be made, the multiple copy switch S5 is closed at the start of the first cycle of the first copy. Switch S5 is a separate control switch which can be closed and opened by the operator. Alternatively, it can be combined with any of a number of well known automatic copy counting commands, for example a ratchet and ratchet mechanism which opens the switch S5 after a predetermined number of 15 copies were made. In either case, when the switch S5 is placed in its multiple copy position MC, the main relay K1 is kept energized by the contact S5 and remains there until the cycle is completed after the opening of this contact. Likewise, the circuit to ground at the base of transistor Q2 is normally maintained by contact S5 in its simple copy position (SC) and is open to allow transistor Q2 to receive a pulse as has already been Explain.

During the multiple copy operations, the single copy operations are repeated successively. But at the end of the second cycle of the photoreceptor 40, when the contact S7 opens, the main relay K1 remains energized by the circuit established by the contact S .5 in its position MC. In addition, the opening of the contact S7 produces a pulse of 100 milli-30 seconds, by the inductive winding of the clutch CL3 and the capacitor C9. The pulse of 100 milliseconds is applied to the base of the transistor Q2 which, in turn, applies a pulse to the transistor Q4 which excites the clutch CL ^ for a time sufficient for the notch 8 to pass above the phototransistor Q3, 'in the same way as the' 'transistor Q1 applies a pulse to the CIΛ clutch at the start of a single copy. When the notch 8 has passed the transistor Q3 and the latter is no longer lit, the transistor Q1 · is turned on, maintaining the power supply of * 28 the clutch ClA * The transistor Q3 is inhibited in the same way for each next copy by contact S6, as in the case of single copy operation. At the last copy, the switch S 5 goes to its position SC (uni-5 copy,) during the second turn of the photoreceptor band 40. With the switch S 5 in this position, the base of the transistor Q2 is grounded , inhibiting the pulse of transistor Q4 which could again activate the CL4 clutch. The contact S5 is also open and interrupts the other circuit to ground 10 of the main relay K1, so that when the contact. S7 opens, relay K1 drops and the machine stops as in the case of a single copy.

Claims (15)

1. Electrophotographic reprographic machine for producing a copy of an original document on a copy sheet, machine characterized in that it comprises a roller of relatively large diameter, a roller of relatively small diameter, a strip endless photoreceptor constituted by a conductive support of which an outer surface is coated with a photoconductive substance, said photoreceptive strip moving on said rollers so as to follow a predetermined path, the machine also comprising a device for driving the photoreceptive strip along said predetermined path, a document lighting device, a reciprocating carriage intended to support a document along said lighting device, several devices arranged near said large diameter roller and intended to load said surface photoconductive, forming an image of said illuminated document on the charged surface to produce a latent electrostatic image, and developing said latent image to make it visible, said machine finally comprising a device intended to bring a copy sheet into contact with said developed image on said photoreceptive strip, a transfer device intended to transfer said developed image of said photoreceptive strip on said copy sheet and a pressure fixing device for said developed image on said copy sheet, said pressure fixing device being arranged with respect to said roll of relatively small diameter so as to receive said sheet of copy when it separates from said photoreceptor strip 30 passing around said small diameter roll. 2. Machine according to claim 1, characterized in that said lighting device comprises an exposure slit through which said original document is illuminated, said image forming device comprising an optical assembly with a shaped optical path from Z, from one end to the other of said exposure slit up to said large diameter roller, said optical path having practically the same length and being arranged above said photoreceptive strip, and said charging, developing and transferring devices. 3. Machine according to claim 1, characterized in that it further comprises an erasing and neutralization device disposed near said photoreceptor strip, along said predetermined path and downstream of said transfer device to erase said image. latent and to neutralize the non-transferred developer so that said developing device can remove said non-transferred and neutralized developer from said photoreceptive strip as it passes through this developing device, thereby cleaning the photoreceptive strip in preparation for carrying out 'a next copy. · U - machine according to claim 3 »characterized in that it further comprises an upper support assembly on hinge intended to jointly support said lighting device, said image forming device, said erasing device and neutralization and said charging device so that said support assembly 20 can be opened by pivoting to allow access to said photoreceptive strip and to said developing device. 5. Machine according to claim 1, characterized in that it further comprises a device intended to angularly offset the axes of said rollers, one with respect to the other, so as to push said photoreceptive strip to move laterally in a predetermined direction toward one end of said rollers, as it moves along its predetermined path. 6 - Machine according to claim 5 »characterized in that it further comprises a flange on one of said rollers, at its end towards which said strip moves laterally, so as to maintain the photoreceptive strip in a predetermined position. 35 7 - Device for controlling an electrophotographic reprographic machine comprising a device for lighting an original document, a device which moves the original document in reciprocating motion in front of said positive lighting device, an endless photoreceptor strip which moves along a predetermined loop path, several devices arranged near said path and comprising a device for loading the photoreceptor strip,. 5 a device for exposing the photoreceptive strip to said original document illuminated to form a latent electrostatic image on said strip, a device for developing said latent image and a device for transferring said developed image onto a copy sheet, device 10 control characterized in that it controls the execution of a copy of said original document every two cycles of the photoreceptive strip along its predetermined path, said control device comprising a device which drives the photoreceptive strip in two cycles along of said predetermined path and a device which switches on said lighting and charging devices during the first cycle and which suppresses switching on of said lighting and charging devices during the second cycle. 8. Device according to claim 7> characterized in that it further comprises a device for starting said transfer device after the start of said first cycle of said photosensitive strip and a device for stopping said transfer device before end of the second cycle of said photoreceptor strip. 9. Device according to claim 7, characterized in that it further comprises a device disposed downstream of said transfer device, intended to erase the latent image and to neutralize the developer which remains on the. photoreceptor strip, said control device further comprising a device for switching on said erasure and neutralization device during the two cycles of said photoreceptor strip so as to erase the latent image and to neutralize the non-developing transferred so that the developing device can remove the developer not transferred during the second cycle of the photoreceptor tape in preparation for the execution of a next copy. 10. Device according to claim 7j characterized * 32 J "in that it further comprises a marker associated with said photoreceptor strip and moving with it, a device for detecting the passage of said marker in a predetermined position, and a controlled device by said detection device 5 and associated with said tape drive so as to stop said tape after a predetermined even number of cycles, this predetermined number of cycles corresponding to twice the number of copies desired. 11. Device according to claim 10, characterized in that said device controlled by said detection device is also associated with said respective lighting, development, transfer, erasure and neutralization devices so as to stop these devices after said predetermined even number of cycles of said photoreceptive strip. 12. Device according to claim 10, characterized in that said marker is a hole in the strip, said detection device consisting of a light source arranged on one side of said hole and a photodetector arranged on the other side of said hole so as to detect the light that passes through this hole. 13. Plain paper reprography machine, comprising a housing which contains an endless photoreceptive strip moving between two rollers which support and drive said strip along a predetermined loop path, an electronic image development device -: latent trostatic on said strip and a device for transferring said developed image on a sheet of = plain paper copy, two waiting rollers intended to bring 1k copy sheet in contact with the developed image on the photoreceptive tape and a tray intended to contain a reserve of copy sheets, machine characterized in that it further comprises a support and movable positioning frame so as to move away from and approach an operating position in order to position the tray copy sheets, and for supporting and positioning the idle rollers and the transfer device in their respective operating position with respect to t to the photoreceptor strip when said support and positioning frame is brought into its operating position. 14. Machine according to claim 13, characterized in that it further comprises an asso-5 tensioning device connected with said support and positioning frame and coupled with one of said rollers so as to move it relative to the another roller when the support frame is positioned in its operating position, so that the photoreceptive strip is stretched. 15 15 - Machine according to claim 13, characterized in that said developing device is movable between a first position aligned with the photoreceptive strip to develop it and a second position offset relative to said strip to allow replacement thereof, 15 the machine further comprising an alignment device coupled to said support frame and intended to bring said developing device into alignment with said photoreceptive strip when said support frame is in position, in operation. 20 16 - Machine according to claim 13, characterized in that it further comprises a mobile device mounted on the machine and intended to support! ' said rollers, and actuated by said movable support frame so as to engage and support said rollers when the support frame is in the operating position. 17. Machine according to claim 13 ,. characterized 3 in that it further comprises a paper tray positioning cam mounted on the movable support frame and => comprising an arm biased towards a latching device in said paper tray so that the latter is positioned in the operating position when the cam arm engages the plate engagement device. 18. Machine according to claim 13, characterized in that it further comprises a retaining cam which can rotate on the movable support frame, and biased towards the machine case so as to bear against it when the frame support and positioning is pulled to a predetermined rest position, the release of said retaining cam being necessary so that the frame VC 34 mobile support can be completely removed from the machine. 19. Electrophotographic reprographic machine intended for producing a copy of an original document on a copy sheet, by transferring a developer image of a photoreceptor onto said copy sheet, machine characterized in that it comprises a first roller, a second roller whose diameter is smaller than that of the first roller, and an endless photoreceptor band movable on said rollers so as to move along a predetermined tre.jet 10, the axes of said rollers being angularly offset relative to each other so as to cause the photoreceptive strip to move laterally in a predetermined direction towards one end of said rollers when the photoreceptive strip travels along its predetermined path. 20. Machine according to claim 19, characterized in that it further comprises a collar on one of the rollers, at its end towards which the strip moves laterally, so as to keep the strip in the same lateral position. . 21. Machine according to claim 19, characterized in that it further comprises two spaced vertical support walls intended to support said rollers so that they can rotate, said first roller being arranged so that its axis is perpendicular to the two. vertical walls while said second roller is disposed of; so that its axis is angularly offset relative to said first roller.