US3062094A

US3062094A - Electrophotographic copying apparatus

Info

Publication number: US3062094A
Application number: US783388A
Authority: US
Inventors: Clyde R Mayo
Original assignee: Xerox Corp
Current assignee: Xerox Corp
Priority date: 1958-12-29
Filing date: 1958-12-29
Publication date: 1962-11-06
Anticipated expiration: 1979-11-06

Description

Nov. 6, 1962 R, MAYO 3,062,094

ELECTROPHOTOGRAPHIC COPYING APPARATUS Original Filed Feb. 7, 1955 4 Sheets-Sheet 2 INVENTOR.

Clyde R. Mayo ATTORNEY NOV- 6, 1962 c. R. MAYO 3,062,094

ELECTROPI-IOTOGRAPHIC COPYING APPARATUS Original Filed Feb. 7, 1955 4 Sheets-Sheet 3 F /G 5 30d INVENTOR.

Clyde R. Mayo A TTOQNE Y Nov. 6, 1962 c. R. MAYO 3,062,094

ELECTROPHOTOGRAPHIC COPYING APPARATUS Original Filed Feb. '7, 1955 4 Sheets-Sheet 4 o V, WR. mm/A wm/ m .w \.4 L 2 0a m.. 90o. 6 1 m. 2-| v E-i flu F ESS.

United States atet 3,062,094 ELECTRPHOTOGRAPHIC CUPYING APPARATUS Clyde R. Mayo, Rochester, N.Y., assignor to Xerox Corporation, a corporation of New York Continuation of application Ser. No. 486,513, Feb. 7, 1955. This application Dec. 29, 1958, Ser. No. 783,388 18 Claims. (Cl. 88--24) This invention relates in general to Xerography and, in particular, to apparatus and mechanism for implementing the xerographic progress and for projecting an original to a moving surface such as a rotating cylinder or a moving plate. This application is a continuation of copending Mayo application Serial No. 486,513, led February 7, 1955, now abandoned.

In Carlson Patents 2,297,691 and 2,357,809 there is disclosed an electrophotographic process, since known as xerography, and apparatus and mechanism for this proc- The apparatus and machines heretofore developed in accordance with the Carlson invention have been manual in operation and relatively time-consuming. Accordingly, it is an object of this invention to provide a xerographic machine or apparatus capable of operating to produce a completed xerographic print in a matter of seconds after original exposure and to repeat the process steps so that a further Xerographic copy can be reproduced immediately thereafter with a total cycle time in the order of fractions of a minute.

lt is a further object of this invention to provide that the exposure of an original to be copied be made to a sensitive moving surface, whether a rotating cylinder or a moving plate, wherein the original to be copied is positioned above a lens system arranged to iix an image of the original on to the moving sensitive surface which in turn is spaced apart from the lens, and where proper registration of the image of the original is made upon the moving surface by having the lens move in relation to the original.

It -is a further object of the invention to provide a xerographic machine capable of operating to reproduce a copy from an original selectively, either one copy of the original or a plurality of copies of the orignal and to form such copies repetitively in quick succession.

It is still another object of the invention to provide a xerographic machine comprising a rotating cylinder having at least a portion of it surface electrophotographically sensitive, such cylinder rotating through a charging station, an exposure station, a developing station, a paper feed and transfer station, and, if desired, a cleaning station and a regenerating station whereby a xerographic image is produced by the successive steps of exposure, development, and transfer. It is a further object of this invention to provide for the use of this machine in connection with slit projection and in such case to arrange for suitable and even lighting and also to provide for the motion of the lens and other parts in a way to avoid vibration thereof.

Another object of the invention is to provide apparatus and mechanism for reproducing automatically a representation of a visible image from the face of a cathode ray tu'be.

Additional objects of the invention will be understood from the following specification and from the drawings in which:

FIGURE l lis a front elevation of a xero-graphic machine according to an embodiment of the invention;

FIGURE 2 is a rear elevation, partly in section, of a machine shown in FIGURE l;

FIGURE 3 is a rear elevation, partly in section, illustrating the mechanism provided for the development station;

FIGURE 4 is a view of a corona charging electrode according to one embodiment of the invention;

FIGURE 5 is a plan View of an alternative form of projection slit advantageously employed under certain circumstances;

FIGURE 6 is a side view, partly in section, of a preferred form of lens carriage and actuating mechanism;

FIGURE 7 is a transverse view, partly in section, along the lines of 7-7 shown in FIGURE 6;

FIGURE 8 is a side view of an alternative embodiment of the invention showing a preferred form of uniform lighting by having the light source connected to and movable with the slit-provided carriage; and

FIGURE 9 shows an embodiment of the invention in connection with the reproduction of the visible image from the face of a cathode ray tube.

Referring more particularly to FIGS. 1 and 2, a xerographic machine generally designated 10 consists of a cylindrical member 11 provided with a xerographically sensitive surface. Around the cylinder are assembled the various stages of operation for the xerographic process. These stages include an exposure station 12, a developing station 13, and a regeneration station 14, paper feed station 15, transfer station 16, and a cleaning station 17 followed by a charging station 18. Positioned above the exposure station and spaced apart are a movable lens system 1'9 and a xed support 20 for the original or master to be copied, together with a slit projection arrangement and a source of light 9, for example, sun lamps, operating preferably on the reilected back o1- opaque system.

At the exposure station, generally designated 12, is a hood or bellows or other shield 21 adapted to protect the xerographic surface from extraneous light and having a slit 22 at its lower portion adjacent to the surface. The upper end of this shield 21 is open to receive an optical image from a master or original as described hereinafter. Closely adjacent but spaced from the shield and positioned above it is a slotted track 24 on which is mounted a carriage 25 supporting and carrying a lens 26 which is thereby movable above and across the upper end of the shield 21. Spaced above this track 24 is a second track 2S, likewise bearing a carriage 29, which carriage has a tranverse slit 30 extending thereacross. Preferably, for ease of motion, both of these carriages may be mounted on balls 27 and wheels 31 respectively or other means or mechanism may be employed to cause these carriages to move or slide easily and smoothly along their track. To avoid vibration of the lens while it is moving, it has been found desirable to mount the lens (see FIGS. 6 and 7) in a heavy metallic carriage 25 and to employ channels 32 formed in the heavy metal carriage 25 for the lens and in track 24, and by positioning for use in the channels four metal balls 27, held in place by a suitable bearing cage (not shown). This heavy metal and ball construction can be machined to a high degree of perfection to avoid the vibration of the lens.

Positioned above the upper track 28 is a fixed support 20 consisting, for example, of a copy board 33 which may consist of a transparent plane member such, for example, as a glass plate or the like, which is adapted to receive a master or original placed face downward, on its upper surface, in position for having its image projected through the lens on to the sensitive surface of the cylinder 11, and positioned over the copy board 33 is a flexible copy cover 23, made, for example, of plastic, for holding copy flat against the upper surface of the copy board.

In order to provide for correlated motion of the lens carriage 25 and slit-provided carriage 29 in their travel across the

respective tracks

24 and 28, whereby an optical image from the original placed face downwardly on copy board 33 can be projected onto the photosensitive surface of the cylinder il in proper coordination with the rotation of the cylinder, there is provided the following carriage-actuating mechanism: Partial gear 34 is integrally a part of the cylinder or optionally is integrally mounted on an axle 35 with which the cylinder rotates. Adjacent to this partial gear is a cam 36 integrally a part of the cylinder or optionally integrally mounted on the axle 35. Adjacent to the partial gear 34 is a gear wheel 37 mounted on or connected with a first or inner pulley wheel 3S and a second or outer pulley wheel 39. The relative sizes of partial gear 34, gear wheel 37, the inner pulley whee 3S and of pulley wheel 39 are coordinated and related so that the circumference of pulley wheel 39 rotates at the same speed as the circumference of cylinder lll, while the inner pulley wheel 3S is of one-half the diameter of pulley wheel 39, whereby its circumference moves at one-half the linear rate of the motion of cylinder il. Cam arrangement 36a, fixed to gear 37, cooperates with cam 36 to give to the lens assembly a gradual start. Around the circumference of partial gear 34.- are gear teeth eil extending along to a length such that pulley 59 is driven through a distance equal to the maximum length of copy which is to be produced from the original on copy board 33. Flexible tapes 4l and 42. are secured to the circumference of

pulleys

33 and 39, respectively. Tape il passes over freely movable wheels 44 positioned in line with track 24 and extending therebyond to a carriage return mechanism which may, for example, be a weight 45 suspended at the free end of tape di. In a similar mener, tape 42 passes over freely movable wheels i6 in line with track 23 and is secured to a return mechanism which likewise may suitably be a weight 47 secured to the free end of tape 4?; after it passes over wheel 46. Tapes 41 and in turn are secured by fasteners 4.18 to

carriages

25 and 29, respectively, whereby linear motion of the tapes draws the carriages along their tracks at a corresponding rate of speed.

From the foregoing, it can be seen that a single rotation of partial gear wheel 34 causes a partial rotation of

pulleys

38 and 39 with the consequent winding up of

tapes

41 and 42 across the pulleys, causing

carriages

25 and 29 to be drawn across their tracks, carriage 25 at a rate of speed equal to one-half the rate of rspeed of the surface of cylinder 11 and carriage 29 at a speed equal to the speed of cylinder il. Upon completion of the drive motion, completed by the release of partial gear 34 from gear 37, the carriage return mechanisms, that is, weights 45 'and 47, return the carriages to their original positions in preparation for another cycle of operation. parent, therefore, that during the drive phase of the cycle an optical image from the original placed on copy board 33 is projected through lens 26, such projected image passing through slit '22 on to the surface of cylinder ll in mirror-image relation such that the image received by the moving cylinder surface is a true projected image of the original to be copied.

In the case of slit projection, it is important that uniform lighting be provided during the projection. The source of light 9, which may be sun lamps, is suitably located to provide for reflected-back or opaque projection between the lens and the original to be copied. it is desirable to illuminate all areas of the slit uniformly during all parts of the cycle of projection. Accordingly, the sun lamps or other source of light 9 may be connected with the movable carriage 29 carrying the slit 3) so that movement of the carriage and slit results in corresponding movement of the light, resulting in uniform lighting of the slit at all times. Such a system is illustrated in FIG. S. The carriage 29 traveling in track 23 is provided with copy board 33 on which the original to be copied may be placed face downwardly. Sun lamps 9 are afiixed to the carriage by means of bracket 9b positioned below the slit 36 to provide for the reflected uniform lighting of the lIt is apg rejection `slit during the transverse movement of the carriage.

The size of the apparatus disclosed may be reduced with the use of a wide angle lens. In such case, it may be that a certain amount of uneven lighting of the slit 1s necessary. A form of slit that may be advantageously employed is illustrated in FIG. 5. Such a slit 381) 1s provided with greater width at its extremes 39C than at its center 39d. This form of slit may also be profitably employed in connection with slit projection where difficulties due to uneven lighting m-ay be encountered.

lt is to be noted that the apparatus described herein may be used for reproductions of the same size as the original or for larger or smaller sizes as may be desired. When one-to-one reproductions are to be made, the lens will be positioned halfway between the photographically sensitive moving surface and the original to be copied. When smaller reproductions are desired, then the lens is positioned closer to the photographic surface than to the original. For example, when the lens is located at onethird the distance from the surface to the original, then a reduction in the reproduction to one-half is accomplished. In the opposite way, larger reproductions may be produced.

In the copying machine herein described, when adjustment of the spacing of the lens between the sensitive surface and the original is made, a corresponding adjustment of the linear distance through which the lens carriage 25 and the carriage 29 provided with a transverse slit should also be made. For example, when tue lens is positioned one-third the distance from the plate to the fixed position of the original as when a half-sized reproduction is desired, the lens should move one-third of the distance that the slit moves through. The rate of speed of the lens to that of the motion of the slit must therefore be adjusted accordingly. ln the machine described, this adjustment may be effected by suitable designing of the size of the respective gear wheels 3d and 37 or the pulleys 3S and 39. Automatic means controlling the movement of the lens and the slit under these different circumstances may be provided so that simple and expedient means may be used to produce, respectively, oneto-one reproduction, enlargements and reductions using the slit exposure system shown. As a general rule, the slit should be small with respect to the diameter of the drum. It has been found that, in the case of a l5 to 3() inch diameter drum, the slit may be adjusted up to one inch to achieve proper radiation intensity.

Disposed adjacent to the exposure station l2 and directly subsequent thereto in the direction of rotation of cylinder il is the development station i3 comprising essentially a developing hopper Sil adapted to receive and contain a charge of a developing material for a xerographic process. Preferably, the developing hopper has side walls 52 and tapering bottom walls 53 which lead down to a discharge orifice 53. A closure member or gate 55 is mounted, for example, pivoteily on a support S6 so a3 to open and close discharge orifice 54. The motion of this gate 55 is controlled by suitable means such, for example, as an electrically operated solenoid 57 which may cause the gate 55 to be pivoted on its support 56. Preferably, a baftie 59 is adjustably located adjacent to the discharge orice 5d and is positioned and adapted to cooperate with gate 55 in closing the developing hopper 5l. When the gate 55 is in its open position, it is close to but free from contact with the surface of cylinder il. Batlle 59 and gate 55 are disposed and positioned to direct the flow of developer material from the hoper against the surface of cylinder ifi.

Desirably, the developer hopper 5l is disposed and located near the upper portion of the cylinder in such position that the developer lmaterial which is delivered from the hopper falls to the surface of the cylinder at a position where the surface is relatively near to the horizontal `but at a definite angle from the horizontal. Thus,

for example, it is desirable that the developer material from the hopper fall upon the cylinder where the cylinder surface is at an angle between about and 45 from the horizontal so that the material can cascade or roll across the surface of the cylinder for a substantial distance in contact with the surface.

At the next subsequent position around the cylinder and preferably located at or below the axis of the cylinder is a developer catcher 6) which may still be regarded as part of the developing station. This developer Catcher may be provided with a catching chute 61 positioned and adapted to catch and receive the development material cascading from the hopper across and 4along the surface of the cylinder and adapted to convey and direct the developer material to a mixing chamber 62. According to one embodiment of the invention, the mixer 62 is in the form of a cylindrical tumbler mounted at an angle of about 20 from the horizontal and having a plurality of vanes 63 (FIG. l). The mixer is mounted on bearing supports 65 adapted to be rotated by suita-ble drive mechanism (not shown) and feeds into a bucket type return elevator comprising a belt 66 carrying buckets 67 around lower and upper wheels 69, the whole elevator mechanism being contained within a shield or casing 70. At its upper end, the bucket elevator feeds into a return chute 71 which in turn feeds the development material into the developer hopper 51 for a repetition of the cycle. At another station around the cylinder 11, it may be desirable to have a reverse charging or regeneration station at which a charge is applied to the sensitive surface, the charge being of polarity opposite to that which is applied for the initial sensitizing step described hereafter. Thus, optionally, a reverse charging or regeneration station 14 may be positioned next subsequent to the developer station in the direction of rotation of the cylinder and prior to the proper feed and transfer stations and 16. In the reverse charging station, generally designated as 14 (see FlG. 1), there is provided a suitable charging member such as a corona discharge electrode 72 consisting of one or more tine conductive strands for corona discharge wires 73, control electrodes '75, and preferably a ground plate 74 similar to the charging electrode 13d to be described hereinafter.

Positioned next and `adjacent to the regeneration station is a copy-feeding station provided with suitable sheet-feeding mechanism adapted to feed sheets of paper successively to the cylinder 11 in coordination with the presentation of the developed image at the copy-feeding station. This sheet-feeding mechanism includes a sheet source 81 such as a tray for a plurality of sheets 82 of a suitable transfer material-that is, typically, sheets of paper or the like and a pair of feed rollers S3 and 84 adapted to direct the sheet material into contact with the rotating drum at a speed preferably slightly in excess of the rate of travel of the surface of the drum. One of these rollers S3 is a driven roller operated by a chain of gears 86, S7 and 8S, driven in turn by a gear 89 integrally connected with the rotating cylinder 11. Preferably, gear S9 is a partial gear whereby the paper feed rollers 83 and tid are driven only during the portion of the cycle where it is desired to feed the sheet material to the surface of the drum. A feeding finger 91 is driven by a shaft 92, which in turn is operated by arrn 93, pivotally secured to fixed support 94, the arm 93 being energized by a feeding member or cam follower 95, driven by cam 96, whereby the feeding finger 91 is adapted to feed the top sheet of the stack 82 to the feed rollers S3 and 84 in coordination with the appearance of the developed image at the paper feed station as may be determined by the cam 96. In this manner, the sheet material is introduced between the feed rollers and is thereby brought into contact with the rotating cylinder 11 at the correct time and position to register with the developed image.

Preferably, at the exact point of contact between the sheet material and the rotating drum, a transfer station 16, consisting of a corona discharge electrode, is positioned to effect transfer of the developed image from the cylinder surface to the sheet material. The transfer electrode consists essentially of one or more corona discharge wires 97 and control electrodes 99 positioned and disposed above a ground plate 98 substantially similar to the discharging electrode 18 to be described hereinafter. The sheet-feeding and transfer mechanism are similar to the type disclosed in Mayo et al. Patent 2,684,902, filed November 23, 1951.

Immediately subsequent to the transfer station 16 are positioned strip lingers y1111 operated by arm lill7 in turn energized by cam member or follower 103 driven by a second cam 104 integrally mounted on or connected with the rotating cylinder 11. These strip or pick-off fingers are adapted to Ibe 4brought into contact with the surface of the cylinder 11 slightly in advance of the sheet material and to strip the sheet material from the cylinder surface, directing the free 4sheet material into a fixing mechanism generally designated 105 and further dened in a copending application Serial No. 232,- 152, tiled June 18, 1951, now Patent No. 2,701,765. The fixing apparatus disclosed in FIG. 2 consists essentially of a heated rotating drum 111 and a corona discharge electrode 112 or the like, spaced closely adjacent thereto and adapted to receive the sheet material therebetween, whereby the sheet material is secured by electrostatic adhesion to the surface of the heated drum, and the developed and transferred image is fixed thereon by conducting heating from the surface of the drum through the sheet transfer material. Cylinder 111 preferably is contained within a housing 113 and is driven by motor 113' operating through drive wheel 114 and belt I11S to drive the heating cylinder at a rate which optionally may be the same as that of the rotation of cylinder 11. Sliding pick-off fingers 116 serve to pick the sheet material from the surface of heated drum 111 and direct it into a tray 117 wherein the completed xerographic print is collected and stored.

Positioned next subsequent to the transfer and pick-up station is a cleaning station generally designated 17, at which is disposed cylindrical brush 121 rotatively mounted, for example, on axle 122 and adapted to be driven by a motor 123 operating through belt 12d. The entire cleaning section is mounted within a housing 125 with a sub-housing or hood 126 surrounding the cylindrical lbrush as disclosed and illustrated in FiG. 2. The cylindrical brush may consist, for example, of rabbit fur secured on the surface of a solid or structural cylinder 127 and be rotated in a direction opposite to the direction of rotation of the cylinder surface at the point of contact, so that the relative motion between the brush surface and the cylinder surface is the sum of the two separate speeds of motion. A filter member 12S may be positioned in one wall of the hood, preferably the lower wall thereof, to permit passage of air therethrough but at the same time to collect dust or electroscopic particles removed from the surface of the cylinder by the brush. In the mechanism as illustrated in FIG. 2, the brush fibers, due to the high centrifugal force caused by the rotating motion, extend outwardly until they reach in contact the cylinder surface, when they are somewhat depressed. Immediately upon release, the brush fibers extend outwardly again from the surface, thus causing a vane-like action which causes a flow of air into the hood area at the space between the hood and the cylinder and out through filter 12S. In this manner, a constant ilow of air serves to free the brush libers from electroscopic particles picked up lby the cleaning action and thus to maintain absence of dust in the surrounding atmosphere. lf desired, this air flow `action may be supplemented through the use of a supplemental vacuum flow from an air blower or the like (not shown).

Next subsequent in the direction of rotation of cylinder lll is optionally positioned a light discharge source such, for example, as a neon light 1.3i placed directly over the surface of the cylinder il and adapted to ood the entire surface of the cylinder with light prior to its entering into the next subsequent process stage of charging, thus assuring at this point complete photoconductive dissipation of any residual electric charge from the photoconductive sensitive surface of the cylinder.

The nal stage through which the rotating cylinder surface passes, which stage may be considered as an initial stage of this or a subsequent cycle, is a charging station 1S wherein the cylinder surface is adapted to pass under a corona discharge electrode, generally designated as in FlG. 2, consisting of one or more tine conductive strands or corona discharge wires 132 optionally with a ground plate 133 at least partially sur-rounding the wires. Control electrodes 134 are provided between the discharge wires 3l32 and the surface of cylinder 1l whereby there occurs a flow of gaseous ions from the wires to the cylinder surface. This corona discharge is of the type described and claimed in copending application Serial No. 221,582, now Patent No. 2,778,946.

Cylinder or drum lll around which are stationed the various stages of the photographic process provides a cylindrical support surface of an electrically conductive material such, for example, as a metal surface or the like, on which is placed a photoconductive insulating layer such, for example, as a layer or coating of vitreous selenium or other photoconductive insulating material. Suitable for this purpose are various photoconductive insulating compositions characterized by an extremely high specific resistivity in the absence of illumination, which resisitivity drops at least several orders of magnitude upon exposure to bright light. Suitable material, in addition to selenium compositions, include, for example, anthracene, sulphur, sulphur-selenium mixtures and the like, as well as other photoactive material characterized 'by high insulation in the dark and by photo-initiated conductivity such, for example, as photoactivation of electrons in the molecular structure to a conductivity band or by other transitory or permanent change in conductivity upon exposure to light. it is to be understood that the cylinder l1 may be a cylinder surface having a photoconductive insulator directly on its surface or may, if desired, have a support member adapted to receive and support in cylindrical conguration one or more separate xerographic members consisting of a conductive backing and a photoconductive layer thereon. Then, if desired, the drum or light member may be directly coated with a vitreous selenium composition or, alternatively, a rigid or llexible xerographic member may be suitably secured to the surface of a cylindrical support member.

In the device and apparatus disclosed in the drawings herein, the various mechanisms connected with the stations of exposure, paper feeding, paper pick olf, and the lil-ie, are controlled by a single unit, gears and partial gears, and by single unit cams, and therefore are adapted to cooperate with a cylinder or drum containing a single xerographic member or a single xerographic station at its surface. It is to be understood, however, that a plurality of such members or stations around the cylinder may be employed and that a plurality of partial gears, cam members, and the like may be used in cooperation therewith, whereby two or more separate xerographic cycles may be accomplished in a single revolution of the cylinder or drum ll. Such an arrangement may be desirable under certain circumstances and be adapted for a plurality of cycles in a single cylinder revolution.

In the disclosure of the preferred form of embodiment of the invention, a cylinder or drum has been employed to provide a movable photosensitive surface. Such a movable surface may be secured in other ways, such as a movable plate or belt and the invention is also applicable thereto.

The mechanism disclosed herein is suitable for the reproduction of one or more copies of an original placed on the copy board By suitable means, such as handpositioning or by mechanical means, the desired original material is placed on the copy board. The cylinder is then energized and exposure takes place with the

carriages

25 and 29 passing across the surface of the copy in synchronized motion and correlated speed according to the rotation of cylinder lli. The exposed portion of the surface of the cylinder then passes into the developing station wherein a suitable developer material is cascaded across the surface and is collected by the developer catcher and returned to the developer proper. The exposed and developed portion of the surface of the cylinder lll then passes to the paper-feeding station and the transfer sta.- tion where it receives a sheet of transfer copy material and passes under a corona discharge whereby the developed image is transferred to the paper or other transfer member` The cylinder, with the adhering transfer sheet, then passes to the pick-up iingers Mil where the sheet is stripped from the cylinder surface and enters the fixing chamber wherein the transferred image is fixed to the transfer sheet by heat fusing or the like. The cylinder surface then passes to the cleaning station where any residual powder is removed by brush 121 and then after coming under discharging light lill the surface passes to the charging electrode l@ where an electrostatic charge is deposited on the surface of the drum and the drum is thus sensitized or re-sensitized and prepared for the succeeding exposure and development cycle. At this stage, if more than one copy is desired, the cycle is repeated until sufficient copies are obtained, whereupon a different original is placed on the copy board and the cycle then repeated as desired.

According to the presently preferred procedure, the development composition employed includes a two-component developer consisting of grossly larger carrier particles and fine electroscopic powder particles, coated on the surface thereof such, for example, as described in Patent No. 2,618,55l. As the process continues through the repetitive cycles, the quantity of electroscopic powder material in the combination developer may become depleted and it accordingly is desirable to replenish the developer composition with additional electroscopic powder, either continuously or from time to time. The replenishment of the developer composition may be achieved by adding to the developer mixture in the tumbler 62 or immediately prior thereto a small additional quantity of the electroscopic powder material. The addition of this small quantity of developer powder may be accomplished manually or, if desired, by automatic means by a replenisher opening 62a as shown in Fl G. l. The developer composition with the replenishing powder is mixed in tumbler 62, whereupon uniform intermixing is achieved and the combination developer is then re-cycled into the developer hopper for re-use through one or more succeeding xerographic cycles.

According to a further embodiment of the invention, the mechanism as herein described is adapted for the reproduction of an optical image formed on the face of a cathode ray tube or like source of conversion of energy. A suitable embodiment of this mechanism may be that disclosed in connection with FIGS. l and 2 wherein the face of the cathode tube is substituted for the original Ztl to be copied as shown in those figures or an embodiment such as shown in FIG. 9 wherein the lens 26 is kept in constant position over the exposure section l2 of the cylinder ll and is not caused to travel back and forth across the exposing station. ln this modification. a cathode tube 99 with its face o is held above the shield 2l of the exposure section which in turn is located above the rotatable cylinder ll. The photosensitive surface of the cylinder ll rotates through the exposure station 12 and then through corresponding developing station, paper feed station, transfer station, cleaning station, and charging station, all as disclosed in FIGS. 1 and 2. An electrical image is fed to the cathode ray tube according to conventional electronic circuits, to yield an image on or moving across the face of the tube in coordination with the rotation of the cylinder. This optical image is projected and focused on to the electrophotographically sensitive cylinder surface to form thereon an electrostatic latent image which in turn is developed and transferred to copy sheet material or the like, all as previously described and shown in connection with FIGS. l and 2. When a cathode ray tube or like source of an optical image is employed in conjunction with the vitreous selenium type of the Xerographic surface, it is preferable that the face of the cathode ray tube contain a phosphor, preferably one which is relatively high in spectral sensitivity in the blue-green range, this presently being the spectral range of greater sensitivity for the vitreous selenium xerographic surface. The sensitivity of the xerographic member or surface is such, however, that it performs satisfactorily with substantially all conventional phosphor light emitters.

While this invention has been described in preferred form, it is to be understood that modifications thereof may be made without departing from the ambit of the invention as dened by the appended claims.

What is claimed is:

l. An apparatus for projecting a light image on a moving surface comprising a copy holder for supporting copy substantially in a plane, illuminating means to illuminate copy supported by the copy holder; said illuminating means including a slotted light shield for exposing a transverse section of the copy holder, a light source for illuminating such exposed section, and means for supporting the light shield and light source for movement to traverse the surface of the copy holder; a movable light receiving surface having a path of movement arranged to receive light refiections from the copy holder, means for moving said surface at a predetermined speed, a light shield interposed between the light receiving surface and the copy holder, a slot aperture in the light shield extending transversely to the path of movement of the light receiving surface, a lens element for focusing light reflections from the copy holder through the slot aperture, a lens carriage for supporting the lens element, said carriage being movable in a path to traverse the plane of the copy holder, means for moving the lens carriage and the light source supporting means at differing predetermined speeds relative to the speed of the light receiving surface, and means to restore the lens carriage and the light source supporting means to their respective traverse starting positions.

2. An apparatus for projecting a light image onto a rotating xerographic drum comprising a copy holder for supporting copy substantially in a plane, means to illuminate copy supported by the copy holder; said illuminating means including a slotted light shield for exposing a transverse section of the copy holder, a light source for illuminating such exposed section, and means for supporting the light shield and light source for movement to traverse the surface of the copy holder; a xerographic drum mounted for rotation about an axis parallel to the plane of the copy holder and arranged to receive light reflections from the copy holder, means for rotating said Xerographic drum at a predetermined speed, a light shield interposed between the xerographic drum surface and the copy holder, a slot aperture in the light shield extending transversely to the path of movement of the xerographic drum surface, a lens element for focusing light reflections from the copy holder through the slot aperture, a lens carriage for supporting the lens element, said carriage being movable in a path to traverse the plane of the copy holder, means for moving the lens carriage and the light source supporting means at differing predetermined speeds relative to the speed of the xerographic drum surface, and means to restore the lens carriage and the light source sup- 10 porting means to their respective traverse starting positions.

3. An apparatus for projecting a light image on a moving surface including a fixed copy support means for supporting copy substantially in a plane, movable illuminating means operatively positioned to traverse and illuminate the copy supported by said fixed copy support means, a movable light receiving surface operatively positioned to receive light reflections from the copy supported by said fixed copy support means, a xed light shield operatively interposed between said light receiving surface and said fixed copy support means, a slot aperture in said light shield extending transversely to the path of movement of said light receiving surface, a movable lens carriage operatively positioned for movement in a path to traverse the plane of said fixed copy support means, a lens element connected to said movable lens carriage for focusing light reflections from the copy supported by said fixed copy support means through said slot aperture, and means operatively connected to said movable illuminating means, said light receiving surface and said movable lens carriage to move said movable illuminating means, said light receiving surface and said movable lens carriage at predetermined speeds relative to each other.

4. The apparatus of claim 3 wherein said movable illuminating means includes a slotted light shield for exposing a transverse section of the copy supported by said fixed copy support means, a light source, and means for supporting said slotted light shield and said light source for movement to traverse the surface of the copy supported by said xed copy support means.

5. An apparatus for projecting a light image on a moving surface including a copy support means for supporting copy substantially in a plane, movable illuminating means operatively positioned for illuminating successive portions of the copy positioned in said copy support means in timed relation to the movement of a lens, a movable light receiving surface operatively positioned to receive light reflections from the copy supported by said copy support means, a fixed light shield operatively interposed between said light receiving surface and said copy support means, a slot aperture in said light shield extending transversely to the path of movement of said light receiving surface, a movable lens means operatively positioned for movement in a path to permit said movable lens means to receive light reflections from the copy supported by said copy support means and means operatively connected to said movable illuminating means, said movable light receiving surface and said movable lens means to move said movable illuminating means, said movable light receiving surface and said movable lens means at predetermined speeds relative to each other.

6. The apparatus of claim 5 wherein said movable illuminating means includes a slotted light shield for exposing a transverse section of the copy supported by said copy support means, a light source, and means for supporting said slotted light shield and said light source for movement to traverse the surface of the copy supported by said copy support means, and said movable rlens means includes a lens mounted on a movable carriage.

7. An apparatus for projecting a light image onto a rotating xerographic drum comprising a copy holder for supporting copy substantially in a plane, illuminating means to illuminate copy supported by the copy holder; said illuminating means including a slotted light shield for exposing a transverse section of the copy holder, a ylight source for illuminating such exposed section, and means `for supporting the light shield and light source for movement to traverse the surface of the copy holder; a xerographic drum mounted for rotation about an axis parallel to the plane of the copy holder and arranged to receive light reflections from the copy holder, means for rotating said Xerographic drum at a predetermined speed, a light shield interposed between the xerographic drum surface and the copy holder, a slot aperture in the light shield extending transversely to the path of movement of the xerographic drum surface, a lens element for focusing light rellections from the copy holder through the slot aperture, -a lens carriage for supporting the lens element, said carriage ybeing movable in a path to traverse the plane of the copy holder, and means `for moving the lens carriage and the light source supporting means at different predetermined speeds relative to the speed of the xero-graphic drum surface.

8. An apparatus for projecting a light image onto a rotating xerographic drum comprising a copy holder for supporting copy substantially in a plane, means to illuminate copy supported by the copy holder; said illuminating means including a slotted light shield for exposing a transverse section of the copy holder, a light source for illuminating such exposed section, and means for supporting the light shield for movement to traverse the surface of the copy holder; a xerographic drum mounted for rotation about an axis parallel to the plane of the copy holder and arranged to receive light reections from the copy holder, means for rotating said xerographic drum at a predetermined speed, a light shield interposed between the xerographic drum surface and the copy holder, a slot aperture in the light shield extending transversely to the path of movement of the xerographic drum surface, a lens element for focusing light rellections from the copy holder through the slot aperture, a lens carriage for supporting the lens element, said carriage being movable in a path to traverse the plane of the copy holder, and means for moving the lens carriage and the light shield supporting means at differing prede-y termined speeds relative to the speed of the xerographic drum surface.

9. An appaaratus for projecting a light image on a moving surface comprising a copy holder for supporting copy substantially in a plane, means to illuminate copy supported by the copy holder; said illuminating means including a slotted light shield for exposing a transverse section of the copy holder, a light source for illuminating such exposed section, and means for supporting the light shield and light source for movement to traverse the surface of the copy holder; a movable light receiving surface having a path of movement arranged to receive light reflections from the copy holder, means for moving said surface at a predetermined speed, a light shield interposed between the light receiving surface and the copy holder, a slot aperture in the light shield extending transversely to the path of movement of the light receiving surface, a lens element for 4focusing light reflections from the copy holder through the slot aperture, a lens carriage for supporting the lens element, said carriage being movable in a path to traverse the plane of the copy holder, and means yfor moving the lens carriage and the light source supporting means at diifering predetermined speeds relative to the speed of the light receiving surface.

l0. An apparatus for projecting a light image onto a moving surface comprising a stationary copy holder for supporting copy substantially in a plane, means to illuminate copy supported by the copy holder, a movable light receiving surface having a path of movement arranged to receive light rellections from the copy holder, means for moving said surface at a predetermined speed, a light shield interposed between the light receiving surface and the copy holder, said light shield having a slot aperture arranged adjacent the light receiving surface and extending transversely to the path of movement thereof, a movable lens element mounted between the copy holder and the slot aperture, said lens element being movable in a path to scan the plane of the copy holder, and means for moving the lens element at a rate proportional to that of the light receiving surface whereby a ilowing image of copy is projected onto said movable light receiving surface.

l1. An apparatus for projecting a light image onto a moving surface comprising a stationary copy holder for supporting copy substantially in a plane, means to illuminate copy supported by the copy holder, a moving light receiving surface having a path of movement arranged to receive light reflections from the copy holder, a light shield interposed `between the light receiving surface and the copy holder, said light shield having a slot aperture arranged adjacent the light receiving surface and extending transversely to the path of movement thereof, a lens element for focusing light reflections from the copy holder through the slot aperture onto said moving light receiving surface, and a lens carriage for supporting the lens element, said lens carriage being movable in a path whereby said lens element scans the plane of the copy holder and means for moving the lens carriage at a predetermined speed relative to said light receiving surface.

l2. An apparatus for projecting a light image onto a moving surface comprising a stationary copy holder for supporting copy substantially in a plane, means to illuminate copy supported by the copy holder, a movable light receiving surface having a path of movement arranged to receive light rellections from the copy holder, means for moving said light receiving surface at a predetermined speed, a light shield interposed between the light receiving surface and the copy holder, a slot aperture in the light shield arranged adjacent the light receiving surface and extending transversely to the path of movement of the light receiving surface, a lens element for focusing light rellections from the copy holder through the slot aperture onto said moving light receiving surface, a lens carriage lfor supporting the lens element, said lens carriage being movable in a path to traverse the plane of the copy holder whereby copy supported by the copy holder is scanned by said lens element, and means for moving the lens carriage at a predetermined speed relative to the speed o-f the light receiving surface.

13. An apparatus for projecting a light image onto a moving surface comprising a stationary copy holder for supporting copy substantially in a plane, means to illuminate copy supported by the copy holder, a movable light receiving surface having a path of movement arranged to receive light rellections from the copy holder, means `for moving said light receiving surface at a predetermined speed, a light shield interposed between the Ilight receiving surface and the copy holder, a slot aperture in the light shield arranged adjacent the light receiving surface and extending transversely to the path of movement of the light-receiving surface, a lens element for focusing light rellections from the copy holder through the slot aperture onto the light receiving surface, a lens carriage 'for supporting the lens element, said -lens carriage being movable in a path to traverse the plane of the copy holder from a start-of-scan position to an endof-scan position whereby said lens element scans copy supported thereon, means for moving the lens carriage at a predetermined speed relative to the speed of the light-receiving surface from said start-of-scan position to said end-of-scan position, and means to restore the lens carriage to its start-of-scan position.

14. An apparatus for projecting a light image on a moving surface including a copy holder for supporting copy substantially in a plane, means to illuminate copy supported by said copy holder; said illuminating means including a light source, and means for supporting said light source for movement to traverse the surface of the copy holder; a movable light-receiving surface having a path of movement arranged to receive light reflections from the copy holder, means for moving said lightreceiving surface at a predetermined speed, a light shield interposed between said light-receiving surface and said copy holder, a slot aperture in said light shield extending transversely to the path of movement of said lightreceiving surface, a lens element for directing light rellections from said copy holder through said slot aperture and onto said light-receiving surface, a lens carriage for supporting said lens element, said lens carriage being movable in a path to traverse the plane of the copy holder, and means for moving said lens carriage and 13 said means for supporting said light source at differing predetermined speeds relative to the speed of said lightreceiving surf-ace.

15. An apparatus -for projecting a light image on a moving surface including a copy holder for supporting copy substantially in a plane, means to illuminate a copy supported by said 4copy holder, said means including a light source, and a carriage for supporting said light source for movement to traverse the surface of said copy holder, a movable light-receiving surface having a path of movement arranged to receive light reections from said copy holder, means for moving said surface at a predetermined speed, a light shield interposed between said light-receiving `surface and said copy holder, a slot aperture in said light shield extending transversely to thc path of movement of said light-receiving surface, a lens element Ifor directing light 4reilections yfrom said copy holder through said slot aperture and onto said lightreceiving surface, a lens carriage `for supporting said lens element, said lens carriage being movable in a path to traverse the plane of said copy holder', means for moving said lens carriage and said carriage for supporting said light source at differing predetermined speeds relative to the speed of said light-receiving surface, and means to restore said lens carriage and said carriage for said light source to their respective traverse starting positions.

16. A copying apparatus including a copy holder for supporting copy substantially in a plane, illuminating means to illuminate a copy supported by said copy holder, a xerographic drum mounted for rotation about an axis, a light shield positioned adjacent the surface of said xerographic drum, a slot aperture in said light shield that extends normal to the path of movement of the surface of said xerographic drum, said slot aperture being arranged adjacent the surface of the xerographic drum, a lens carriage, a lens element mounted on said lens carriage, said lens carriage being mounted for movement to transport said lens element in a path to scan copy on said copy holder and to project a owing image of copy through said slot aperture in said light shield onto said xerographic drum, and means connected to said xerographic drum and to said lens carriage to move said lens carriage at a predetermined speed relative to the speed of the surface of said xerographic drum as it is rotated by said means.

17. An apparatus for projecting a Ilight image from a stationary copy onto a xerographic drum including a copy holder for supporting a copy substantially in a plane, illuminating means to illuminate a copy supported by said copy holder, xerographic drum mounted for rotation about an axis, a light shield interposed in the light path between said copy holder and said xerographic drum, a slot aperture in said light shield extending transversely to the path of movement of the surface of said xerographic drum, a lens element for focusing light reections from a copy on said copy holder through said slot aperture of said light shield and onto said xerographic drum, a lens carriage `for supporting said lens element, said lens carriage being mounted for movement in a -path to traverse the plane of said copy holder, and means connected to said xerographic drum and said lens carriage to rotate said Xerographic drum and to periodically move said lens carriage at a predetermined speed relative to the surface speed of said xerographic drum from a starting position to a drive release position, and means to restore said lens carriage to its traverse starting position.

18. An apparatus for projecting a radiation image from a stationary original onto a photosensitive member including a copy holder for supporting an original substantially in a plane, illuminating means for illuminating an original supported by said copy holder, a cylindrical member adapted to support a photosensitive member mounted for rotation about an axis, means for imparting rotation to said cylindrical member, a light shield interposed in the light path between said copy holder and said cylindrical member, a slot aperture in said light shield extending transversely to the path of movement of the surface of said cylindrical member, a lens element for focusing radiation reflections from an original on said copy holder through said slot aperture of said light shield onto said cylindrical member, a lens carriage for supporting said lens element, said lens carriage being mounted for movement in a path to traverse the plane of Said copy holder, a drive means associated in axial alignment with said cylindrical member and connected for rotation therewith, a driven means mounted adjacent said drive means and adapted to be coupled to said drive means to provide coincident rotation thereof after said drive means has rotated a lirst predetermined distance and adapted to be uncoupled from said drive means kafter an additional predetermined rotation, a flexible member adapted to be driven by said drive means and having a portion thereof coupled to said lens carriage, said exible member being thereby adapted to impart linear motion to said lens carriage and to synchronize the linear speed of said lens carriage with the peripheral speed of said cylindrical member.

References Cited-in the le of this patent UNITED STATES PATENTS 2,123,151 Petit et al. July 5, 1938 2,153,186 Henderson Apr. 4, 1939 2,478,555 Yule Aug. 9, 1949 2,487,671 Pratt et al Nov. 8, 1949 2,606,478 Pratt et al Aug. l2, 1952 2,807,190 Oldenboom Sept. 24, 1957 -2,830,491 Domeshek Apr. 15, 1958 2,859,673 Hix et al Nov. 11, 1958 FOREIGN PATENTS 551,455 Great Britain Feb. 23, 1942