US3062108A

US3062108A - Electrophotographic copying apparatus

Info

Publication number: US3062108A
Application number: US783258A
Authority: US
Inventors: Clyde R Mayo
Original assignee: Xerox Corp
Current assignee: Xerox Corp
Priority date: 1955-02-07
Filing date: 1958-12-29
Publication date: 1962-11-06
Anticipated expiration: 1979-11-06

Description

NOV. 6, C. R. MAYO ELECTROPHOTOGRAPHIC COPYING APPARATUS 4 Sheets-Sheet 1 original Filed Feb. 7, 1955 ATTORNEY Nov. 6, 1962 c. R. MAYo 3,062,108

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

Clyde R. Mayo ATTORNEY.

Nov. 6, 1962 C, R, MAYO 3,062,108

ELECTROPHOTOGRAPHIC COPYING APPARATUS Original Filed Feb. 7, 1955 l 4 Sheets-$1681. 3

Fla 5 30d mvENroR.

Clyde R.Mayo

Afro/mfr Nov. 6, 1962 c. R. MAYO 3,062,108

ELECTROPHOTOGRAPHIC COPYING APPARATUS Original Filed Feb. 7, 1955 4 Sheets-Sheet 4 INVENTOR. Clyde R. Mayo United rates 3,062,108 ELECTROPHOTOGRAPHIC COPYING APPARATUS Clyde R. Mayo, Rochester, N.Y., assignor to Xerox Corporation, a corporation of New York Original application Feb. 7, 1955, Ser. No. 486,513. Di-

vided and this application Dec. 29, 1958, Ser. No.

This invention relates in general to xerography and, in particular, to apparatus and mechanism for implementing the xerographic process and for projecting an original to a moving surface such as a rotating cylinder or a moving plate. This application is a division of copending Mayo application Serial No. 486,513, filed 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 process. 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.

It 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 fix 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 original 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 its surface electrophotographically sensitive, such cylinder rotating through a charging station, an exposure station, a developing station, a paper yfeed 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 tube.

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

FIGURE 1 is a front elevation of a xerographic machine according to an embodiment of the invention;

FIGURE 2 is a rear elevation, partly in section, of a machine shown in FIGURE 1;

yFIGURE 3 is a rear elevation, partly in section, illus- 3,062,108 Patented Nov. 6, 1962 ICC trating 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. l 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 19 and a fixed 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 reliected back or 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 Lipper end of the shield 21. Spaced above this track 24 is a second track 28, likewise bearing a carriage 29, which carriage has a transverse 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 bas 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 2S 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 construc tion can be machined to a high degree of perfection to avoid the vibration of the lens.

Positioned above the upper track 23 is a fixed support 2t) 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 fiat 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 a image from the original placed face downwardly on copy board 33 can be projected onto the photosensitive surface of the cylinder 11 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 38 and a second or outer pulley wheel 39. The relative sizes of partial gear 34, gear wheel 37, the inner pulley wheel 38 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 il, while the inner pulley wheel 38 is of one-half the diameter of pulley wheel 39, whereby its circumference moves at onehalf the linear rate of the motion of cylinder 1l. 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 40 extending along to a length such that pulley 39 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 41 and 42 are secured to the circumference of

pulleys

38 and 39, respectively. Tape 41 passes over freely movable wheels 44 positioned in line with track 24 and extending therebeyond to a carriage return mechanism which may, for example, be a weight 45 suspended at the free end of tape 41. In a similar manner, tape 42 passes over freely movable wheels 46 in line with track 28 and is secured to a return mechanism which likewise may suitably be a weight 47 secured to the free end of tape 42 after it passes over wheel 46. Tapes 41 and 42 in turn are secured by fasteners 48 to

carriages

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

yFrom the foregoing, it can be seen that a single rotation of partial gear wheel 34 causes a partial rotation of pulleys 3S 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 speed of the surface of cylinder 11 and carriage 29 at a speed equal to the speed of cylinder 11. 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. It is apparent, 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 11 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 30 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. 8. The carriage Z9 traveling in track 28 is provided with copy board 33 on which the original to be copied may be placed face downwardly. Sun lamps 9 are axed to the carriage by means of bracket 9b positioned below the slit 30 to provide for the reflected uniform lighting of the i projection 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 is necessary. A form of slit that may be advantageously employed is illustrated in FIG. 5. Such a slit 30]; is provided with greater Width at its extremes 30C than at its center 30d. This form of slit may also be profitably employed in connection with slit projection where diliiculties due to uneven lighting may be encountered.

It 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 size 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 the 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. In the machine described, this adjustment may be effected by suitable designing of the size of the respective gear wheels 34 and 37 or the

pulleys

38 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, one-to-one reproduction, enlargement 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 30 inch diameter drum, the slit may be adjusted up to one inch to achieve proper radiation intensity.

Disposed adjacent to the exposure station 12 and directly subsequent thereto in the direction of rotation of cylinder 11 is the development station 13 comprising essentially a developing hopper 51 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 54. A closure member or gate 55 is mounted, for example, pivotally on a support 56 so as 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 batiie 59 is adjustably located adjacent to the discharge orifice 54 and is positioned and adapted to cooperate with gate 55 in closing the developer hopper 51. When the gate 55 is in its open position, it is close to but free from contact with the surface of cylinder 11. Baflie 59 and gate 55 are disposed and positioned to direct the ow of developer material from the hopper against the surface of cylinder 11.

Desirably, the developer hopper 51 is disposed and located near the upper portion of the cylinder in such position that the developer material 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 60 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 along the surface of the cylinder and adapted to convey and direct the devel- Oper 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 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 suitable 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 15 and 16. In the reverse charging station, generally designated as 14 (see FIG. l), there is provided a suitable charging member such as a corona discharge electrode 72 consisting of one or more line conductive strands for corona discharge wires 73, control electrodes 75, and preferably a ground plate 74 similar to the charging electrode 136 to be described hereinafter.

Positioned next and adjacent to the regeneration station is a copy-feeding station provided with suitable sheetfeeding 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 materialthat is, typically, sheets of paper or the likeand a pair of

feed rollers

83 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 83 is a driven roller operated by a chain of gears 86, 87 and 88, driven in turn by a gear S9 integrally connected with the rotating cylinder 11. Preferably, gear 89 is a partial gear whereby the

paper feed rollers

83 and 84 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 arm 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

83 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 l98 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 181 operated by arm 102, 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 be brought 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 sheet material into a fixing mechanism generally designated 105 and further defined in a copendirig application Serial No. 232,152, filed .lune 18, 1951, now Patent No. 2,7101] 65 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 11S 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. Y 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 y123 operating through belt 124. The entire cleaning section is mounted within a housing 125 with a sub-housing or hood 126 surrounding the cylindrical brush 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 128 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 liow of air into the hood area at the space between the hood and the cylinder and out through filter 128. `In this manner, a constant flow of air serves to free the brush fibers from electroscopic particles picked up by the cleaning action and thus to maintain absence of dust in the surrounding atmosphere. If desired, this air flow action may be supplemented through the use of a supplemental vacuum flow from an airblower or the like (not shown).

Next subsequent in the direction of rotation of cylinder 11 is optionally positioned a light discharge source such, for example, as a neon light 1311 placed directly over the 7 surface of the cylinder 11 and adapted to flood 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 18 wherein the cylinder surface is adapted to pass under a corona discharge electrode, generally designated at 130 in FIG. 2, consisting of one or more ne conductive strands or corona discharge wires 132, optionally with a ground plate 33 at least partially surrounding the wires. Control electrodes 134 are provided between the discharge wires 132 and the surface of cylinder 11 whereby there occurs a ow 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 11 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 resistivity 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 11 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 configuration 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 flexible 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 off, and the like, 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 11. 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 copyboard 33. 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 2S and 29 passing across the surface of the copy in synchronized motion and correlated speed according to the rotation of cylinder 1l. rIhe exposed portion of the surface of the cylinder then passes into the developing station wherein a suitable developed 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 11 then passes to the paper-feeding station and the transfer station 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. rhe cylinder, with the adhering transfer sheet, then passes to the pick-up lingers 101 where the sheet is stripped from the cylinder surface and enters the xing 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 `131 the surface passes to the charging electrode d3@ 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 suiiicient 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. 2,618,551. 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 FIG. l. The developer composition with the replcnishing powder is mixed in tumbler 62, whereupon uniform intermixing is achieved and the cornbination developer is then re-cyled 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 20 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 12 of the cylinder 11 and is not caused to travel back and forth across the exposing station. In this modification, a cathode tube 9@ with its face 90a is held above the shield Z1 of the exposure section which in turn is located above the rotatable cylinder 11. The photosensitive surface of the cylinder 111 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 a 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 electrophotographieally sensitive cylinder surface to form thereon an electrostatic latent image which in turn is developed and transferred to copy sheet materialor the like, all as previously described and shown in connection with FIGS. 1 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.

What is claimed is:

1. A Xerographic reproducing apparatus including in combination a Xerographic plate journaled for rotation,

charging means positioned to impose a uniform electrostatic charge on the surface of said xerographic plate, support means for supporting copy substantially in a plane, means for scanning copy supported by said support means and for projecting an image thereof onto the xerographic plate, whereby to form an electrostatic latent image of copy on said xerographic plate,

developing means to develop an electrostatic latent image, whereby to form a xerographic powder irnage of copy on said Xerographic plate,

and image transfer means to transfer a Xerographic powder image to support material,

said last recited means including sheet feeding means for superposing sheet material onto a Xerographic powder image on said xerographic plate and transfer means for causing a Xerographic powder image to adhere to sheet material, pick-off means to separate sheet material from said Xerographic plate after image transfer,

and means actuated in accordance with the rotational position of the Xerographic plate to initiate operation of said sheet feeding means and said pick-off means in timed relation.

2. In a Xerographic machine,

the combination of a Xerographic plate journaled for rotation,

charging means positioned to apply a uniform electrostatic charge to said xerographic plate,

a copy board for supporting copy substantially in aA plane.

a scanning means having a lens positioned to project an image of copy on said copy board onto said Xerographic plate to form an electrostatic latent image thereon,

developing means positioned to effect development of an electrostatic latent image on said Xerographic plate,

a container for sheet material,

sheet feed means positioned to feed sheet material seriatim from said container to said Xerographic plate,

transfer means positioned to effect transfer of a developed electrostatic latent image from said xerographic plate to sheet material,

pick-off means positioned adjacent to said transfer means to effect removal of sheet material from said xerographic plate,

drive means connected to said xerographic plate to rotate said xerographicplate, said drive ymeans being l@ connected to said scanning means to actuate said scanning means to scan copy at a predetermined speed relative to the movement of said xerographic plate, and programmer means driven by said drive means to actuate said sheet feed means and said pick-off means in timed relation to the actuation of said scanning means. 3. In a xerographic machine, the combination of a Xerographic plate mounted for rotation, charging means positioned to apply a uniform electrostatic charge to said Xerographic plate, a copy board for supporting copy substantially in a plane, scanning means including a movable lens to project an image of copy yon said copy board onto said xerographic plate, said movable lens being arranged to traverse the plane of said copy board by movement from a start-of-scan position to an end-of-scan position, developer means positioned to develop an electrostatic latent image on said Xerographic plate, a container for sheet material, sheet feed means positioned to feed sheet material seriatim from said container into contact with said Xerographic plate, transfer means positioned to eect transfer of a developed image from said xerographic plate onto sheet material, pick-off means positioned `adjacent said transfer means to remove sheet material from said Xerographic plate, drive means connected to said Xerographic plate for rotating said Xerographic plate, said drive means being connected to said movable lens for moving said movable lens through a predetermined path from a start-of-scan position to an end-of-scan position in timed relation to the movement :of said xerographic plate, said driving means including means to return said movable lens from its end-of-scan position to its start-of-scan position, and means connected to said sheet feed means to effect feeding of sheet material to said Xerographic plate in timed relation with the rotational position of said Xerographic plate. 4. A Xerographic copying apparatus including a Xerographic plate mounted for rotation,

charging means positioned adjacent said Xerographic plate for applying an electrostatic charge on said Xerographic plate, Ia copy board for supporting copy substantially in a plane, a slotted light shield positioned adjacent the surface of said Xerographic plate,

. lens means mounted for movement in a path to traverse the plane of said copy board from a start-of-scan position to an end-of-scan position, to project an image of copy on said copy board through said slotted light shield `onto said xerographic plate to form an electrostatic latent image of copy on said xerographic plate,

developing means positioned to develop an electrostatic latent image on said Xerographic plate,

a container for sheet material,

sheet feed means positioned to feed sheet material seriatim from said container into contact with said Xerographic plate,

transfer means positioned to effect transfer of a developed powder image from said Xerographic plate onto sheet material,

pick-off means positioned adjacent said transfer means to effect removal of sheet material from said xerographic plate,

drive means connected to said Xerographic plate for rotating said xerographic plate,

and scan control means connected to said drive means for moving said lens means from said start-of-scan position to said end-of-scan position to scan copy in timed relation to the movement of said Xerographic plate and to return said lens means to said startof-scan position,

said scan control means also being connected to said sheet feed means to effect the feeding of sheet material into contact with a developed image on said Xerographic plate and for actuating said pick-off means to remove sheet material from said Xerographic plate.

5. A xerographic machine including a xerographic plate mounted for rotation,

charging means positioned to apply a uniform electrostatic charge on said Xerographic plate,

a copy board for supporting copy,

a slotted light shield positioned adjacent the surface of said Xerographic plate,

lens means mounted for movement in a p-ath to scan the optical image path from said copy board to there- `by project an image of copy through said slotted light shield onto said xerographic plate,

movable illuminating means mounted for movement to traverse the plane of said copy board,

a container for sheet material,

sheet feeding means operatively positioned adjacent said container to feed sheet material seriatim into contact with said Xerographic plate,

transfer means positioned to effect transfer of a deve oped powder image from said Xerographic plate to sheet material,

drive means connected to said Xerographic plate, said lens means and said illuminating means to drive said Xerographic plate, said lens means and said illuminating means at predetermined speeds relative to each other, said lens means and said illuminating means being moved fro-m original starting positions through predetermined paths to form an electrostatic latent image on said Xerographic plate during rotation thereof,

said drive means including means to return said lens means and said illuminating means to their respec- `tive starting positions,

and control means connected to said Xerographic plate to operate in timed sequence to the movement of said xerographic plate to effect operation of said sheet lfeeding means and said pick-off means.

6. In a Xerographic machine,

the combination of a Xerographic plate mounted for rotation,

Icharging means positioned to apply a uniform electrostatic charge on said Xerographic plate,

a copy board for supporting copy substantially in a plane,

scanning means including lens means mounted for movement to traverse the plane of said copy board to expose the charged surface of said Xerographic plate to an image of copy on said copy board, whereby to form an electrostatic latent image of copy on the Xerographic plate,

a container for sheet material,

transfer means positioned to effect transfer of a developed image from said xerographic plate to sheet material,

pick-off means positioned to remove sheet material from said Xerographic plate,

`drive means connected to said Xerographic plate and said lens means to move said Xerographic plate and said lens means at predetermined speeds relative to each other,

and control means connected to said drive means to effect operation of said sheet feed means in timed relation to the rotational position of said xerographic plate.

7. In a Xerographic machine,

the combination of a xerographic plate journaled for rotation, Y

charging means positioned to apply a uniform electro static charge on said Xerographic plate,

a copy board for supporting copy substantially in a plane,

a scanning means having a light source and a movable lens positioned to project an image of copy on said copy board onto said Xerographic plate,

developing means positioned to effect development of an electrostatic latent image formed on said Xerographic plate,

a container for sheet material,

pick-off means positioned adjacent said transfer means, said pick-off means being adapted to pick off sheet material from said Xerographic plate,

drive means connected to said Xerographic plate to rotate said Xerographic plate,

said drive means including means to effect movement of said movable lens whereby said lens is moved across the plane of said copy board to project an image of copy onto said xerographic plate as it is rotated to form an electrostatic latent image,

and said drive means further including means to effect operation of said sheet feed means in timed relation to the formation of an electrostatic latent image on said Xerographic plate whereby sheet material is advanced to said Xerographic plate to coincide with the position of a developed electrostatic latent image on said Xerographic plate.

8. A xerographic reproducing apparatus including in combination a Xerographic plate journaled for rotation,

charging means positioned to impose a uniform electrostatic charge on the surface of said Xerographic plate,

support means for supporting copy,

means for scanning copy supported by said support means and for projecting an image thereof onto the xerographic plate, whereby to form an electrostatic Ilatent image of copy on said Xerographic plate,

ydeveloping means to develop an electrostatic latent image, whereby to form a Xerographic powder image of copy on said Xerographic plate,

and image transfer means to transfor a xerographic powder image to support material,

said last recited means including sheet feeding means 4for superposing sheet material onto a Xerographic powder image on said Xerographic plate and transfer means for causing a Xerographic powder image to adhere to sheet material,

pick-off means to separate sheet material from said Xerographic plate after image transfer,

and means actuated in accordance with the rotational position o-f the Xerographic plate to initiate operation of said sheet feeding means and said pick-off means in timed relation.

9. In a xerographic machine,

the combination of a xerographic plate journaled for rotation,

charging means positionedI to apply a uniform electrostatic charge to said Xerographic plate,

a copy board for supporting copy,

developing means positioned to eiect development of an electrostatic latent image on said Xerographic plate,

a container for sheet material,

drive means connected to said xerographic plate to rotate said Xerographic plate, said drive means being connected to said scanning means to actuate said scanning means to scan copy at a predetermined speed relative to the movement of said xerographic plate,

and programmer means driven by said drive means to actuate said sheet feed means and said pick-off means in timed relation to the actuation of said scanning means.

References Cited in the file of this patent UNITED STATES PATENTS 998,663 Wood July 25, 1911 2,123,151 Petit et al. July 5, 1938 2,153,186 Henderson Apr. 4, 1939 2,211,766 Brown Aug. 20, 1940 2,703,280 Butterfield et al. Mar. l, 1955 2,781,705 Crumrine et al. Feb. 19, 1957 FOREIGN PATENTS 579,513 Canada July 14, 1959