US2889758A - Electrophotographic printer - Google Patents

Description

June. 9, 1959 w. D. BOLTON ELECTROPHOTOGRAPHIC PRINTER 6 Sheets-Sheet '1 Filed Dec. 24. 1954 INVENTOR. WALLIS D. BOLTON ATTORNEY June 9, 1959 w. D. BOLTON ELECTROPHOTOGRAPHIC PRINTER 6 Sheets-Sheet 2 Filed Dec.

OP wmDmOaxm W. D. BOLTON ELECTROPHOTOGRAPHIC PRINTER Fi s CUITS TRIGGER FORMING 8. DISPLAY CIR- CHARACTER FIG; 5..

June 9, 1959 w. D. BOLTON ELECTROPI-IOTOGRAPHIC PRINTER 6 Sheets-Sheet 4 Filed Dec. 24. 1954 June 1959 w. D. BOLTON ELECTROPHOTOGRAPHIC PRINTER 6 Sheets-Sheet 5 Filed Dec. 24, 1954 mm? 9m W 5 M Sm HI m n 0% D 8 v on T 0 q Fur. on im N I m: o w: o QEU QU U u n] I mmu MEAL Q finu owo OHPH June 9, 1959 w. D. BOLTON 2,889,758

ELECTROPHOTOGRAPHIC PRINTER Filed Dec. 24, 1954 2 6 Sheets-Sheet 6 O 36 72 108 I44 180 216 252 288 324 360 I8 54 90 I26 I62 I98 234 270 306 342 CARD START -S HEET START SPRAY TRANSFER WIPE CLEAN FORM CARD

CFl

CONTACT LC CB3 & CB4

FIG. 8

nited States Patent ELECTROPHOTOGRAPHIC PRINTER Wallis D. Bolton, Vestal, N.Y., assignor to International Business Machines Corporation, New York, N.Y., a corporation of New York Application December 24, 1954, Serial No. 477,556

Claims. (-Cl. 951.7)

This invention relates to electrophotographic printing machines in general, and to electrophotographic document originating machines in particular.

The preferred embodiment of the invention to be described herein is an electrophotographic printing machine commonly referred to as a xerographic printer. As is well known to persons familiar with this phase of the graphic arts, xerography is a term applied to a printing process in which latent electrostatic images are rendered visible by a pigmented electroscopic powder, often referred to as xerographic toner, the resulting electroscopic powder image being transferred and thereafter afiixed to a print receiving material so as to afford a permanent printed copy which depicts the latent electrostatic image. An apparatus employing such a printing process is shown and described in Carlson Patent No. 2,357,809, issued on September 12, 1944. The steps followed in this printer include electrically charging an electrophotoplate having a photoconductive layer on an electrically conductive backing member, exposing the charged plate to an optical image so as to form a latent electrostatic image thereon, dusting the latent electrostatic image with xcrographic toner in order to develop this image so that the configuration thereof is visible, transferring the xerographic toner onto a print receiving material, such as paper for example, and removing any excess toner remaining on the electrophotoplate after the preceding transfer step and prior to the next electrophotoplate charging step.

Another kind of xerographic printer employing a printing process somewhat different than the aforementioned Carlson one, is shown and described in Schaifert Patent No. 2,576,047, issued on November 20, 1951. This printing machine embodies a continuously rotating drum on which an electrically insulating or non-conducting image layer is secured. This image layer of permanent design is electrostatically charged prior to being dusted with xerographic tones. The toner will be attracted to and will adhere to the charged surface area of the permanent design image layer so that when the toner is transferred onto a print receiving material, the xerographic toner so transferred will define a configuration corresponding to the image layer of permanent design. This type of printing is commonly referred to as xeroprinting in order to distinguish the same from other types of xerographic printing. It is to be observed that a xeroprinting machine is in essence a printing duplicator because any number of copies may be produced from a single permanent design image layer.

This invention pertains to a xerographic printing machine for originating documents each of which may bear different information. The preferred embodiment of this invention is a xerographic document originating machine which comprises a continuously rotating drum having an electrophotoplate thereon that includes a photoconductive layer on an electrically conductive backing member. During the first cycle of machine operation, a permanent design image layer of insulating material is formed on the electrophotoplate to represent information from a first source, such as a record. This record may have the format of a letter lacking the heading thereof, for example, and the body of which is directed to a particular group or class of persons, such as doctors for instance. During each one of subsequent machine cycles, a nonpermanent xerographic image is developed on the electrophotoplate within the limits of the permanent design image layer, to represent information from a second source such as another record. This latter record has the heading information pertaining to a single recipient of the afore-mentioned letter and, of course, there are a plurality of these latter records. Since the so-called non-permanent xerographic image is literally erased each machine cycle, a new heading is developed each machine cycle. As a result, after the first cycle the documents originated during each print impression operation are in effect so-called form-letters each consisting of common body information and a different heading. Thus, a plurality of persons within a group or class designation such as the medical profession, will each receive a personalized copy of this document. Since each such personalized document is printed in its entirety during one print impression operation, the document will have a more favorable effect on the recipient thereof than does the usual form-letter which almost always includes a printed body and a typewritten heading. After the machine cycle during which the last original document is printed, the permanent design image layer of insulating material is automatically removed from the photoconductive layer of the electrophotoplate, to thereby prepare the plate for another series of machine operations.

An object of this invention is to provide an improved original document printing machine.

Another object of this invention is to provide an original document printing machine employing electrophotographic principles.

In keeping with the foregoing, a still another object of this invention is to provide an improved method of printing.

Another object of this invention is to provide a xerographic printing machine wherein a permanent design image layer of insulating material is formed on an electrophotoplate prior to a first print operation, and is automatically removed from the electrophotoplate after the last print operation.

Another object of this invention is to provide an electrophotographic printing machine for preparing original documents bearing information from two separate sources of input.

And yet another object of this invention is to provide an improved printing machine for preparing original documents in accordance with a print impression master plate having both permanent and non-permanent design image layers thereon.

Other objects of the invention will be pointed out in the following description and claims and illustrated in the accompanying drawings, which disclose, by way of examples, the principle of the invention and the best mode, which has been contemplated, of applying that principle.

In the drawings:

Fig. 1 is a somewhat diagrammatic view of an electrophotographic document originating machine.

Fig. 2 depicts the steps that take place during the 1st, 2nd, nth and nth+1 machine cycles.

Fig. 3 shows a format record, heading record cards and an original document as prepared by the electrophotographic printing machine.

Fig. 4 is a diagrammatic view of the format record removing mechanism.

Fig. 5 is a diagrammatic view of an electrophotographic printer employing a cathode ray tube optical input.

Figs. 6a and 6b together form a wiring diagram of ti e control apparatus for governing the operation of the electrophotographic printer.

Fig. 7 is a block diagram of the motor drive.

Fig. 8 is a timing chart.

General description Referring to Fig. l, heading record cards 10 to be operated on are stacked in hopper 11 and are fed, one by one, each card cycle out of the hopper towards a stacker 12 by conventional picker mechanism. Successive pairs of feed rolls 132tl cause a record card to be advanced during each card cycle past reading brush station 21 and optical scanning station 22. For reasons to become clear as the description advances, the aforesaid feed rolls are driven at speeds whereby the record cards are fed past brush station 21 and optical station 22 at speeds correlated with the surface speed of xerographic drum 23.

Associated with the optical scanning station is a single light ray projector 24 for directing a band of light rays upon a constricted center of the aperture in member 26, to thereby effect a conventional light scanning operation of each record card 10 advanced past station 22, whereby an image of the record card printed information identified by reference numeral 27 (see also Fig. 3) is transferred to the photoconductive layer surface of the electrophotoplate 29 on xerographic drum 23.

The cylinder 33 of the xerographic drum is mounted for rotation on a shaft 28 and is driven by an electric motor 93 (Fig. 7) in a clockwise direction. This drum has secured thereto an electrophotoplate 29 (Fig. 1), said plate consisting of a photeconductive layer 31 of amorphous selenium, for example, on an electrically conductive backing member 32 of aluminum, for example. The plate 29 is flexed around cylinder 33 as shown, and is attached thereto in any one of the numerous conventional ways of attaching a printing plate to a supporting cylinder, such as by means of suitable clamping devices. It is important, however, that in whatever manner this attachment is made, it is necessary that the backing member 32 of the electrophotoplate 29 be in good electrical contact with the electrically grounded drum cylinder 33 connected to shaft 28.

A so-called format record 34 (see also Fig. 3) is caused to be moved during the first machine cycle from a feeding station 36 to a receiving station 37. In so doing, this record 34 is caused to move with the xerographic drum 23, and between the electrophotoplate 29 K and a transparent carrier belt 38. The transparent belt is supported for movement by a couple of freely mounted wheels 39 and 41 each of which is carried by a respective shaft attached to a frame member 42 biased by springs 43 and 44 in a direction towards the outer surface of cylinder 33. As to be explained in detail hereinafter, at the time that format record 34 is being moved with the xerographic drum under transparent belt 38 and past exposing station 45, there will be no record card 10 in the process of being advanced through optical scanning station 22. Thus, a steady light radiation of fairly constant intensity will be reflected from mirror 46 through lens 47 and transparent belt'38, and onto and through format record 34.

As stated previously, the xerographic drum 23 is driven in a clockwise direction by an electric motor via shaft 28. As successive incremental areas of the light sensitive photoconductive layer 31 are moved past ion-producing charging unit 43 of the type shown and described in Carlson Patent No. 2,588,699, issued on March 11, 1952, the aforesaid layer is electrostatically charged.

Referring particularly to Figs. 1 and'2, during the first machine cycle, cam 49 which isattached to shaft'28 for rotation therewith will act upon a rod 51 at approximately 71 (see also Fig. 8) so as to move the rod against the action of a biasing spring 52. Inasmuch as a slide gate 53 for normally preventing the format record 34 from extending beyond gate 53 and to a point between belt 38 and xerographic drum 23, is fixed to rod 51, the gate will be moved in a direction to create an opening for record 34. Due to the pushing action of biased record pusher 54 on the rearward end of format record 34, the forward end of this record will be moved into the bite of transparent carrier belt 38 and electrophotoplate 29. It should be pointed out here that pusher 54 is slideably mounted on the supporting frame 55. The format record is released from feeding station 36 at a time the forward endof electrophotoplate 29 is slightly beyond the gate 53 and accordingly, record 34 will be moved with plate 29'past the afore-mentioned constant light radiation passing through the transparent carrier belt 38 in exposing station 25.

Consequent upon the exposure of the photoconductive surface of electrophotoplate 29 to the optical image of format record 34, a latent electrostatic image is produced on plate 29 for the reason that those electrically charged incremental areas of the photoconductive plate 31 onto which light rays are directed, are discharged, whereas those areas not illuminated by light rays remain charged. Hence, after electrophotoplate 29 is exposed to this optical image, a latent electrostatic image corresponding to the information on format record 34 will remain, this latent electrostatic image being one wherein the dark areas corresponding to markings within the format record retain an electrical charge, and the light areas corresponding to background are no longer charged.

Continued rotation of the xerographic drum 23 in a clockwise direction will move the record 34 into a receiving station 37 whereat record removing fingers 83 and 84 will strip record 34 off plate 29. Continued rotation will also cause the latent electrostatic image on plate 29 to be moved into a developing chamber 56 (see also Fig. 2) which is similar to the one utilized in the printing apparatus of the afore-mentioned Schaffert Patent No. 2,576,047. The developing chamber is one wherein xerographic toner of the type described in Copley Patent No. 2,659,670, which issued on November 17, 1953, is permitted to cascade onto the photoconductive layer'surface of electrophotoplate 29 and, of course, over the latent electrostatic image thereon. As a result of the charged toner adhering to only those afore-mentioned dark areas of plate 29 which are also charged, a toner image which visibly defines the latent electrostatic image is developed on the surface of the electrophotoplate. Surplus xerographic toner that does not adhere to the surface of plate 29, will fall into a suitable receiving receptacle within chamber 56.

A still further rotation of the xerographic drum will cause the toner image on electrophotoplate 29 to move out of chamber 56 and into the realm of a toner fixing station 57 whereat the toner image powder particles are somewhat solidified and the toner image is caused to ad here to the surface of electrophotoplate 29 for a reason other than the latent electrostatic image. This station 57 is comprised of an electromagnetically controlled spray apparatus having a reservoir with a solvent 65 therein, such as methylene chloride for example. The operation of piston 58 in a manner to be described in detail hereinafter, causes a solvent spray to be ejected from nozzle 59 onto a heated element 61. This heated element is provided in order to actually break up the large solvent particles in the spray into extremely minute condensation type vapor particles. It has been found by experiment that good xerographic toner solvent fixing may be much morereadily obtained by employing a vapor rather than a mist or spray. The subjection of he toner image on electrophotoplate 29 to the solvent vapor will cause the xerographic toner to be fixed to the plate so as to provide a permanent design image layer assefias of insulating material which is secured to the photoconductive plate 31.

A further rotation of the xerographic drum causes the permanent design image layer on plate 29 to move out of fixing station 57 and into the toner transfer, or printing, station. A transversely shiftable transfer roller 62 is caused to be in an inoperative position during the first machine cycle so as to prevent a print impression operation from taking place. Inasmuch as a suitable shifting transfer apparatus is shown and described in copending US. patent application, Serial No. 419,314, filed by C. I. Fitch on March 29, 1954, now Patent No. 2,807,233, and since this apparatus per se is not a part of this invention, reference may be had to this patent for more detailed information.

Briefly, however, the transfer roller 62 comprises an inner metallic conductive portion 63 and an outer portion 64 of very resilient or yielding material having a high electrical resistance of at least ohms per cubic centimeter as, for example, a layer of soft conducting rubber. Ann 68 on which transfer roller 62 is mounted, is spring biased in a direction so that roller 62 is away from the surface of xerographic drum 23 and print receiving web 66 is normally out of contact with the surface of the xerographic drum 23 and the electrophotoplate 29. In order to effect a print impression operation, the control solenoid 67 therefor is energized, to there by move arm 68 about a stud shaft 69 in a direction whereby transfer roller 62 is moved towards the surface of xerographic drum 23 and web 66 is moved into contact with plate 29. The positive potential applied to the roller causes toner particles to migrate from the xerographic drum to the print receiving web.

In order to remove any excess xerographic toner particles that might remain on the surface of plate 29 prior to electrically charging the incremental photoconductive layer areas again by ion-source charging unit 48 during the next machine cycle, a rotating plush roller 71 is provided. This cleaning roller is positioned within a housing 72 for retaining the toner removed by the clockwise rotating action of the roller upon the plate 29, from the surface of the electrophotoplate. A vacuum cleaner unit (not shown) may also be utilized with housing 72 in order to remove xerographic toner accumulated therein.

A continued rotation of the xerographic drum in a clockwise direction will cause the incremental areas of electrophotoplate 29 to be moved past a permanent design image layer wiping station 73. During the first machine cycle and all document originating machine cycles up to and including the nth machine cycle, the apparatus at the wiping station will be disabled. However, after the last original document is printed on web 66, the apparatus at Wiping station 73 will be rendered operated due to the energization of magnet '74. This magnet will attract an armature 75 which is pivotally mounted on a shaft 76, so that the three rows of electrophotoplate wiping sponges 77 attached to the upper portion of armature 75, are moved into engagement with the surface of electrophotoplate 29. At this time, the camming member '78 which is also attached to the upper portion of armature 75, will act upon a gate 7Q so as to permit some of the liquid toner solvent 81 to flow to each of the sponges 77 via respective connecting tubes 89. The solvent saturated sponges '77 will act upon the permanent design image layer on the surface of electrophotoplate 29 in such a manner so as to wipe the plate surface clean, i.e., to remove the adhering fixed toner design by unfixing the same with solvent 81. The sponges are preferably attached to their holders in a way that they may be readily removed therefrom when replacement of a sponge is necessary.

During the second machine cycle, the successive incremental areas of electrophotoplate 29 now having the permanent design image layer of insulating material thereon, are charged electrically as they are moved past ion-producing charging unit 48 (see also Fig. 2). At approximately 38 of the second machine cycle, the first record card 10 will be advanced by a picker mechanism to the first set of feed rolls 13-14. The machine timing is such that this record card is moved past optical scanning station 22 at a time whereby the information 27 (see also Fig. 3) on the record card is projected onto a region of the electrophotoplate 29 corresponding to area 35 on format record 34, and within the limits of the permanent design image layer corresponding to the format record Consequent upon the exposure of this surface area of photoconductive layer 31 to the optical image of printed information 27, a latent electrostatic image thereof is formed. In view of the fact that the aforesaid permanent design image layer on xerographic plate 29 is composed of an insulating material (actually fixed xerographic toner), the electrical charge placed thereon by charging unit 48 is not removed as a result of subjecting the permanent design image layer to light radiation. Hence, after photoconductive layer 31 is exposed to the optical image of the record card, a latent electrostatic image corresponding to information on format record 34 and record card 10, will remain on xerographic plate 29. This latent electrostatic image actually depicts an original document, such as document 34a in Fig. 3, comprised of information from format record 34 and record 10.

The advancement of the incremental areas of electrophotoplate 29 through developing chamber 56 will cause this original document latent electrostatic image to be developed by the action of xerographic toner thereon (see Figs. 1 and 2). Inasmuch as it is desired to effect a print impression of this so-called original document toner image in order to produce an original document thereof, the apparatus at fixing station 57 must be disabled. The transfer roller 62, however, Will be in a shifted position, i.e., one wherein the print receiving web 66 is in engagement with xerographic drum 23, during the second machine cycle. As stated previously, the electrical potential applied to the transfer roller will cause the charged toner particles to migrate from the xerographic drum to the print receiving web. Of course, since the toner is pigmented, the same will be readily distinguishable from the background of Web 66 and will provide a readable printed document. Pressure fixing rollers 77 and 78 are utilized to fix those toner images which are transferred to web 66. A sufiicient line contact pressure of 500 pounds per lineal inch of contact, for example, will cause the xerognaphic toner to flow into the fibers of the web material. An oil pad 79 is provided to remove any excess toner which may tend to cling to the upper fixing roller 77. It should be pointed out that a web 66 is shown in Fig. 1 instead of separate document sheets for the sake of simplicity. The Web may be out after printing, of course, to provide separate documents. It also should be pointed out that since means for feeding and controlling the feeding of a web are not a part of this invention, the same will not be described herein. Any suitable arrangement such as the one shown and described in copending Hix et a1. copending US. patent application, Serial No. 419,392, filed on March 29, 1954, will be satisfactory.

Each machine cycle after the second machine cycle will be similar to the second cycle so long as record cards 10 are available in stacker 11 for feeding to hopper 12. In response to the feeding of the last record card 10 from stacker if during the nth machine cycle, a last original document will be printed on web 66. It is after the printing of this last document that the apparatus at plate wiping station 73 is rendered operated and the permanent design image layer on electrophotoplate 29 is removed.

As indicated previously, during the machine cycle following the cycle during which the last original document is printed on web 66, i.e., the nth +1 cycle, the

apparatus at wiping station 73 isrendered operated. That is, magnet 74 is energized via circuits to be described hereinafter, whereupon armature 75 is moved so that the solvent saturated sponges 77 are brought into wiping engagement with the surface of photoconductive layer 31 on electrophotoplate 29. The continued rotation of xerographic drum 23 while the sponges 77 are in wiping engagement will cause the permanent design image layer of insulating material to be wiped off (see also Fig. 2). Hence, the entire photoconductive layer of electrophotoplate 29 will be cleaned and prepared for another series of document originating operations.

Operation and circuits Let it be assumed that a so-called form-letter dealing with the subject of medicine is to be sent to each of live hundred persons in the medical profession. The format record 34' (Fig. 3) which, as stated previously, would contain all parts of such a letter except for the heading information, is placed in feeding station 36 (see also Fig. 1). Five hundred record cards each having heading information 27 thereon are placed in hopper 11. By depressing the start key, normally open (n/o) contacts 91 (Fig.- 6a) will be closed to complete a circuit to relay R19 from line 92 through normally closed (n/c) stop key contacts 94 and start key contacts 91, and relay R10 to line 93. The electrical supply lines 92 and 93 are connected to a suitable power source identified by the reference numeral 96. Inasmuch as hopper contacts 97 are closed whenever record cards are in hopper 11 (see also Fig. l), and since relay R19 has been picked due to the depression of the start'key, a hold circuit for relay R10 will be completed from line 92 through contacts 94, 97 and Rltta, and relay R19 to the other side of the line. As to be brought out shortly, this action will energize motor 98 (Fig. 7) and electromagnet clutch 81. Should it be desired to stop the machine by depressing the stop key whereby normally closed contacts 94 (Fig. 6a) are separated, the hold circuit for relay R10 will be maintained via cam contacts C6 until approximately 355 (see also Fig. 8) of a given machine cycle. It is to be observed that the foregoing action will also take place when hopper contacts 97 open consequent upon the last record card 10 being fed out of hopper 11.

It should be brought out at this time that CF cams operate only when the record card feeding mechanism operates, and C cams and CB cams operate whenever the xerographic drum rotates.

The heavy duty motor control relay HD will be energized when contacts R10b close, whereby contacts HDa (Fig. 7) and HDb will be closed to place electric motor 98 and electromagnetic clutch 81 across power source 99. Motor 98 is employed to drive the record card feeding mechanism shown in Fig. 1 as well as the xerographic drum mechanism. As is shown in Fig. 7, clutch 101 is used to couple the drive motor 98 to card picker mechanism control cam 25 and is controlled by clutch magnet 102 (see also Fig. 6a), the operation of which will become clear as the description advances. On the other hand, clutch 81 is for coupling the drive motor to the xerographic drum. Both of the clutches latch at 29 (see also Fig. 8) of the machine cycle following the one during which the control magnets therefor are de-energized.

First cycle-The depression of the start key will cause motor 98 to operate and to impart a rotational movement to xerographic drum23 at 29 of the first cycle after clutch 81 is also energized. As the forward end of electrophotoplate 29 (refer to Figs. 1 and 2) moves in a clockwise direction, the photoconductive layer 31 will have an electrostatic charge imparted thereto by unit 48. At approximately 71 (see also Fig. 8) rod 51 is acted upon by cam 49, and the forward edge of format record 34 is released through the opening controlled by gate 53 and intothe .bite of belt SS-andplate :29. As. a result of being sandwiched between transparent belt 38 and electrophotoplate 29,'format record 34 is caused to move through the exposing station 45 whereat a constant light radiation is reflected by mirror 46 towards xerographic drum 23. This will cause a latent electrostatic image of format record 34 to be formed on photoconductive layer 31. With a continued rotation of the xerographic drum, the incremental areas of the electrophotoplate are moved past developing chamber 56 whereat the latent electrostatic image is developed so as to provide a visible toner image. This image, it must be remembered, corresponds to the format record.

Referring once again to Fig. 6a, at approximately 48 of the first cycle (see also Fig. 8), cam contacts C1 close to complete a circuit to energize relays RIP and R2P. Cam contacts CFI in the relay R2? circuit make at 22 and break at 40 of a record card feed cycle.

Hence,'inasmuch as clutch 101 (see also Fig. 7) latches Y up at 29 of a machine cycle, and since the clutch islatched during the first machine cycle because clutch magnet 102 is not energized, cam contacts CFl 'willbe closed when cam contacts C1 make during the first machine cycle. it willbe recalled that the cam for controlling contacts CF1 is rotated only when the clutch 101 is elfective. Thus, during all subsequent machine cycles when record cards 10 are being fed from hopper 11 to stacker 12, the camcontacts CF1 will be separated when cam contacts C1 close, and relay R21 will not be energized.

The hold circuit for relay R1 is from line 92 through contacts R and Rla, and relay RlH to the other side of the line. A parallel circuit to contacts R100 includes cam contacts C11 and hopper contacts 82 so that relay R1 will be maintained picked so long as either relay R10 remains energized or there are cards in hopper 11. The

hold circuit for relay RZH is effective from approximately 54 to 18 of the second machine cycle, via cam contacts C2 (see also Fig. 8) and relay contacts R211. It may be concluded then that relay R1 will be maintained picked once the start key is depressed and as long as there are record cards in hopper 11, whereas relay R2 will re-- main picked for only one cycle following the first machine cycle.

At approximately 216 of the first machine cycle, the leading end of electrophotoplate 29 will enter the effective realm of fixing station 57 (see also Fig. 1). Since it is necessary to make a permanent design image layer of the format record toner image, the mechanism at fixing station 57 must be rendered operated during this first machine cycle. Thus, spray magnet 103 is energized at approximately 216 from line 92 (Fig. 6a) through cam contacts C3, relay contacts R2b, Rild and R1242, and magnet 103 to line 93. During the time interval from 216 to 314, all of the incremental areas of electrophotoplate 29 with the toner image thcreon will move past fixing station 57. It is for this reason that spray magnet 193 is energized and de-energized six separate tirncs until 314. This action will operate piston 58 in a reciprocatory manner an equal number of times so that a spray of solvent 65 will be directed onto the heating element 61. As mentioned previously, the action of the solvent spray on heating element 61 will cause a vapor thereof to form, which vapor will fix the toner image on plate 29.

At approximately 270, the leading end of electrophotoplate 29 will be in line with shifting transfer roller 62. Inasmuch as relay R2 is picked during the'first machine cycle, however, transfer magnet 67 for con trolling the shifting action of transfer roller 62 will not be energized because the circuit to magnet 67 includes normally closed contacts R20.

Hence, in view of the charging, exposing, developing and fixing steps that take place during the first machine cycle (see also Fig. 2), a permanent design image layer is caused to be formed and secured to the surface of electrophotoplate 29.

Second cycle.lnasmuch as relay R1 (Fig. 6a) is maintained picked during all machine cycles, the card feed clutch magnet 102 for controlling clutch 101 (see also Fig. 7) is first energized at approximately 20 and until 40 of the second machine cycle. The circuit for energizing magnet 102 is completed from line 92 through contacts C5, R1b and R1411, and magnet 102 to the other side of the line.

The foregoing action will couple card picker cam 25 (see also Fig. 7) mechanically to drive motor 98 so that at approximately 38 of the second machine cycle, the picker feed cam follower 30 (see also Fig. 1) will drop into a low dwell in cam 25. Since the cam follower mechanism is biased by a spring (not shown) in a direction to maintain constant engagement between follower 30 and the surface of cam 25, the card picker mechanism will advance the bottommost record card 10 in stacker-11 towards the first set of feed rolls 13-14. As mentioned previously, the action of feed rolls 13-20 is such to advance each of the record cards 10 at a speed correlated to the surface speed of xerographic drum 23; more particularly, the correlation of speeds is such that the printed matter 27 (see also Fig. 3) on each record card 10 is caused to be scanned by the apparatus in station 22 at a time when the portion of the photoconductive layer 31 corresponding to the region 35 of record 34, is moving past the optical station. Rod 51 (Fig. 1) is acted upon by cam 19 during the second machine cycle, but this is of no consequence because there are no format records in feeding station 36 any longer.

In a manner described hereinbefore, the first record card is scanned during the second machine cycle as it is moved through optical station 22, whereby a latent electrostatic image of the information 27 (see also Fig. 3) is impressed on the area of the photoconductive layer 31 corresponding to the format record area 35. The light rays directed to impinge upon the permanent design image layer of insulating material, will not discharge the same; however, all of the incremental areas of the photoconductive layer 31 except for the afore-mentioned area corresponding to area 35 will be discharged by the light radiation applied thereto. A continued rotation of the xerographic drum will cause the afore-mentioned charged areas to be developed by the xerographic toner in chamber 56.

As the xerographic plate 29 is moved within the elfective range of fixing station 57 during the second machine cycle, the developed toner image will not be fixed because control magnet 103 (Fig. 6a) will not be energized due to open contacts R212.

During this second machine cycle the transfer magnet 67 will be energized at approximately 270, however, to thereby move the transfer roller 62 (see Figs. 1 and 2) towards xerographic plate 29. At this time, the toner defining the original document identified by the reference numeral 34a in Fig. 3, and electrostatically adhering to the permanent design image layer and the photoconductive layer 31 corresponding to region 35a, will be transferred onto the surface of print receiving web 66.

The print receiving web movement is controlled by a mechanism (not shown) whereby the web is advanced with electrophotoplate 29 only while the web is in contact therewith. The print receiving web may be subsequently advanced through a document cutting station or a sO-called bursting machine for separating the successive document print impressions into original documents.

Nth cycle.It is during this machine cycle that the last record card 10 is fed from hopper 11. A print impression on web 66 is obtained in the same manner as one is elfected during the second machine cycle. However, during this nth machine cycle normally closed hopper contacts 104 (Fig. 6a) will make as the last rec- 0rd card 10 is moved out of stacker 11. Furthermore, as this record card is advanced from feed rollers 1314 to rollers 15-16, the card lever contact 107 is closed as a result of card lever 106 being acted upon by the card. Thus, consequent upon the contacts 104 and 107 closing, relay R11 will be energized during the nth machine cycle. A hold for this relay is provided through cam contacts C7 which, as may be seen in Fig. 8, are closed from approximately 59 to 40 of the next machine cycle. This latter circuit is completed from line )2 through contacts C7 and R11a, and relay R11 to line 93. At approximately 20 of the next machine cycle, i. e., the nth+1 cycle, cam contacts C8 will make to complete a circuit from line 92 through contacts C8 and R11b, and relay R12 to line 93. The hold circuit for relay R12 is completed through contacts C9 and R12a until approximately 10 of the nth+2 machine cycle.

Inasmuch as hopper contacts 97 open at the same time that hopper contacts 104 close, the hold circuit for relay R10 is caused to open during the nth machine cycle when cam contacts C6 separate at approximately 355 of the nth cycle. However, since relay R11 is already picked at the time relay R10 is dropped out, the motor control relay HD will remain energized via contacts R110. Furthermore, due to the fact that relay R11 will drop out at approximately 40 of the nth-l-l cycle when cam contacts C7 separate (see also Fig. 8), contacts R12b, are placed in parallel circuit with contacts R101: and R in order to maintain the heavy duty motor relay HD picked so as to provide a sufliciently long runout time.

Relay R1 will drop out at 355 when contacts R10c open because contacts 82 will already be open. Thus, the record card feeding mechanism will latch up at 29 of the nth-l-l machine cycle because normally open contacts Rlb will prevent a circuit to clutch magnet 102.

Nth-I-l cycle.-At approximately 30 of this machine cycle, cam contacts C10 will make (see also Fig. 8) in order to complete a circuit to wiping mechanism control magnet 74 (Figs. 1 and 6a) via contacts R12d. As ex plained previously, the operation of the mechanism at this station will cause sponges 77 to be moved into engagement with the surface of electrophotoplate 29. The continued rotation of xerographic drum 23 against the Wiping action of the solvent saturated sponges 77, will remove the permanent design image layer from plate 2% to clean the surface of the plate.

As the xerographic drum continues to rotate, photoconductive layer 31 will become charged by unit 48 and discharged by the constant intensity light radiation at ex posure station 25. Since there is no electrostatic charge present at this time on xerographic plate 29, there will be no toner image developed (see also Fig. 2). The spray magnet 103 will not be energized due to the fact that contacts R12e are separated, and transfer magnet 67 will not be energized because contacts R12c are separated. At approximately 10 of the nth+2 machine cycle, relay R12 will drop out, and motor magnet HD will become de-energized as will motor 98 and electromagnet clutch 81 (see also Fig. 7). The xerographic drum will continue to rotate however due to its own momentum until clutch 81 latches up at 29.

Supplemental description and summary The xerographic printer shown in Fig. 1 may quite easily be adapted for use as a systems duplicator; that is, a printing machine whereby a predetermined number of duplicate copies may be made from a single printing plate. To be used as a systems duplicator, a format record 34 to be duplicated must be placed into feeding station 36 and two record cards 10 must be placed in hopper 11. The second or uppermost record card in the hopper is a dummy card and is necessary in order to keep the hopper contacts in an operated status while the xerographic machine is providing a plurality of printed copies of the format record. The first or bottommost record card it) in the hopper will have no printed information thereon but instead simply a digit representing hole in a card control column.

Upon depression of the start key, the xerographic printer will begin operating in the manner previously described, whereupon format record 34 will be moved past exposure station 25 in order to form a latent electrostatic image of the record on photo-conductive layer 31 of electrophotoplate 29. During the first machine cycle, this latent electrostatic image will be developed within chamber 56 and fixed by the mechanism of station 57. During the second machine cycle, the permanent design image layer now formed will be charged by unit 48 and developed within chamber 56 so that a toner image will be available for transfer onto print re ceiving web 65. During the second machine cycle, the first or bottommost record card 16 will be advanced by the record card picker mechanisininto the bite of feed rollers 13 and 14. The index hole in the card control column will be read by the apparatus at station 21 and will be entered into an accumulator controlled by add magnet 111 (see Fig. 6a). The storage of a value other than zero in this accumulator will cause the printing machine to prevent the feeding of the second record from hopper 11, and will cause the prrinting of a number of duplicate copies of the format record, to correspond to the information in the card.

Let it be assumed that the first recordcard 10 (Fig. 1) has a 4 digit representing hole punched therein. Thus, at 4-index time a 4 digit value will be entered into the accumulator (similar to one shown and described in Lake et a1. Patent No. 2,328,653, which issued on September 7, 1943) controlled by magnet'111 via the circuit from line 92 through cam contacts CB1 and CB2, card lever contacts 112, the apparatus at sensing station 21, the plug wire connecting hubs 113 and.114, contacts Rlob 11/0, and add magnet 111 tothe other side of the line. Relay R16 will be picked at this time inasmuch as R16? will be energized at 54 of the first machine cycle via cam contacts C2, and maintained energized via cam contacts C12 (see also Fig. 6b) until 90 of the next following or second machine cycle. Subtract magnet 37 will be pulsed at zero index time in order to declutch the accumulator. Relay R14P will be energized at 279 of the first machine cycle when cam contacts C40 close, and will be maintained picked by the circuit from line 92 through contacts Risa and R14b. Switch 36 is provided to prevent therelay R14? circuit from forming during other machine operations. Itis to be observed that relay R15 may be picked during a machine cycle only if the Wiper arm 116 thereof is in contact with conducting segment and common strip 115. Thus, with the 4 digit value having been entered into the accumulator during the second machine cycle, relay R15 cannot be energized during this machine cycle because wiper arm 115 will be in contact with the conducting segment 4 and strip 115. It should be pointed out here that the readout device shown and described in Brand et al. Patent No. 2,502,9l9 which issued on April 4, 1950, may be used with the accumulator. Thus, relay R14 will remain picked and clutch magnet 102 (see also Fig. 6a) will not be energized when cam contacts C make. Furthermore, after cam contacts C12 break at 90 to drop out relay in the second machine cycle, a circuit may be completed to add magnet 111 via cam contacts CB3 and CB4, and relay contacts R14c and R1617 n/c at 9- index time. This circuit will be effective during the third machine cycle to enter a 9 digit'value into the accumulator. The entry of this'digit will cause wiper arm 1.16 to be moved from the conductingsegment to conducting segment 3. Thus, relay R15. willnot be picked during the third machine cycle. During thefourth machine cycle, another 9 digit value will be entered into the accumulator via the foregoing circuit and the wiper element will be moved from the conducting segment 3 to the conducting segment 2. Similarly, during the fifth machine cycle, a 9 digit entry will cause the wiper arm of the accumulator controlled by magnet 111 to be moved from the conducting segment 1 to the conducting segment 0.

At 144 of the fifth machine cycle, relay R15 will be energized through cam contacts C13. This will cause relay R14 to drop out immediately when contacts R15a break, and the circuit including the contacts CB3 and CB4 to open when contacts R14c separate. In addition, the circuit to the clutch control magnet 1 32 will be conditioned so that at 20 of the fifth machine cycle, clutch magnet 102 will be energized. Hence the sec- 0nd record card 10 in hopper 11 will be moved out of the hopper, and since this card will have no data punched therein, it will simply be fed into stacker 12.

It must be pointed out that source records or record cards from which printed duplicates are made, need not necessarily be used. Another embodiment of this invention is shown in somewhat diagrammatic form in Fig. 5 to include a cathode ray tube 120 which is controlled by character forming and display circuits identified by reference numeral 121. The circuits 121 are controlled, in turn, by a mechanically governed trigger arrangement 122 which is rendered on, for example, at just about the time that optical exposure is to be made. After the photoconductive layer on plate 29 is exposed to the characters formed on the face of the cathode ray tube, the trigger 122 is rendered off so as to extinguish the cathode ray tube. An apparatus suitable for effecting the formation of characters on the face of a cathode ray tube 120 and for projecting the characters onto a xerographic drum is shown and described on page of a printed publication entitled Review of Input and Output Equipment Used in Computing Systems and published by the American Institute of Electrical Engineers for Joint AIEE-IRE-ACM Computer Conference of March 1953.

While there have been shown and described and pointed out the fundamental novel features of the invention as applied to a preferred embodiment, it will be understood that various omissions and substitutions and changes in the form and details of the device illustrated and in its operation may be made by those skilled in the art, without departing from the spirit of the invention. It is the intention, therefore, to be limited only as indicated by the scope of the following claims.

What is claimed is:

1. In a cyclically operable electrophotographic printer of the class described comprising an electrophotoplate having a layer of photoconductive insulating material thereon; record information scanning means; means effective during a first cycle of printer operation for forming on said electrophotoplate a design image layer of permanently adhering insulating material, said means including a first record feeding mechanism for moving a format record past said scanning means so that a latent electrostatic image of the information on said format record is produced on the surface of said electrophotoplate, said means further including electric circuit means for controlling the operation of said first record feeding mechanism so that said mechanism is operative to move a format record only during the first cycle of printer operation, means for developing said latent electrostatic image by depositing a finely divided substance on said image so as to render said image visible, means for permanently fixing the substance defining the developed image on the surface of said electrophotoplate; means effective during a second cycle of printer operation for effecting a print operation, said print effecting means including a second feeding mechanism for moving record cards past said scanning means so that a latent electrostatic image of the information on said record cards is formed on said electrophotoplate within limits defined by said permanent design image layer, said print effecting means further including electric circuit means for controlling the operation of said second feeding mechanism to disable said mechanism during the first cycle of printer operation, means for charging the surface of said permanent design image layer, means for de veloping said record card latent electrostatic image and said permanent design image layer by depositing an electroscopic powder thereon, and means for transferring the powder on said surfaces onto a print receiving material.

2. In a printer according to claim 1, means operative in a cycle of printer operation next following the cycle during which the last record card is moved past said scanning means for removing said permanent design image layer from said electrophotoplate.

3. In a device according to claim 1, means operative during each cycle of printer operation to remove excess electroscopic powder on the surfaces of said permanent design image layer and said photoconductive insulating material prior to moving said electrophotoplate past said scanning means, whereby the area of said photoconductive insulating material within the limits of said permanent design image layer is cleaned in preparation for another record card latent electrostatic image.

4. A device according to claim 1 additionally including means for detecting the operation of said second feeding mechanism whereby record cards are caused to be moved past said scanning means, and control means governed by said detecting means for disabl'ing said transfer means during the cycles of printer operation that record cards are not moved past said scanning means.

5. An electrophotographic printer of the class described comprising an electrophotoplate, ion-producing means caused to be effective a first time to electrostatically charge said electrophotoplate, optical means for exposing said electrophotoplate to a light image so as to form a latent electrostatic image thereon, powder depositing means caused to be effective a first time to dust the surface of said electrophotoplate so as to develop said latent electrostatic image, means for permanently aflixing the developed powder image on the surface of said electrophotoplate in the configuration of said image, said ion-producing means caused to be eifective a second time to electrostatically charge the permanently fixed powder image adhering to the surface of said electrophotoplate, said powder depositing means caused to be eflective a second time to dust said permanently fixed image with a pigmented transferable material, means for transferring said pigmented material onto print receiving material in the configuration of said image, means for moving said electrophotoplate, and printer control means for governing the operation of the aforesaid preceding means so that said preceding means are effective with respect to the moving incremental areas of said electrophotoplate in sequence in the order recited.

References Cited in the file of this patent UNITED STATES PATENTS 2,357,809 Carlson Sept. 12, 1944 2,624,652 Carlson Jan. 6, 1953 2,703,280 Butterfield et a1. Mar. 1, 1955 FOREIGN PATENTS 154,222 Australia Nov. 18, 1953

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