US3244084A - Web marking device for xerographic reproducing apparatus - Google Patents

Description

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M IL ES DAVIS A T TOI'PNE YS M. DAVIS WEB MARKING DEVICE FOR XEROGRAPHIC REPRODUCING 'APPARATUS Filed Oct. 50, 1964 M. DAVIS April 5, 1966 WEB MARKING DEVICE FOR XEROGRAPHIC REPRODUCING' APPARATUS 2 Sheets-Sheet 2 Filed Oct. 30, 1964 m. .bfi

-EN J.: /Tmt INVENTOR. MILES DAVIS BY ATTORNEYS United States Patent O 3,244,084 WEB MARKING DEVICE FOR XEROGRAPHIC REPRODUCING APPARATUS Miles Davis, Rochester, N.Y., assigner to Xerox Corporation, Rochester, N.Y., a corporation of New York Filed Oct. 30, 1964, Ser. No. 407,697 1 Claim. (Cl. 95-1.7)

This invention relates to improvements in xerographic reproduction apparatus and, particularly, to an improved device for marking and cutting a web type of surface on which xerographic reproductions are formed. More specifically, this invention relates to improvements in xerographicreproduction apparatus by which a support surface web on which xerographic reproductions are to appear may be marked for cutting in spaced relation to the leading and trailing edges of the reproduction corresponding to the leading and trailing edges of the original documents being reproduced.

It is the practice on automatic xerographic printers, such as the type disclosed in Patent No. 3,049,968, entitled, Xerographic Reproducing Apparatus, to operate a continuously moving paper web support surface from a supply roll to a takeup roll in between which xerographic reproductions are printed thereon. Since the original document, from which the reproduction is formed, may vary in dimension and can be reproduced by the xerographic apparatus in magnified relation, a wide variance of spacing between successive prints may be required. In addition, it is the usual practice to move the paper web at a constant rate of speed, say, for example, approximately feet per minute (4 inches per second) and, in so doing this, a continued absence of reproduction causes a sizable accumulation of scrap paper on the takeup roll. For example, one minutes hesitation on the part of a human operator between feeding successive originals to the apparatus effects approximately 20 feet of scrap paper. On the other hand, accurately timed successive feeding of originals for lll/z-inch reproductions results in approximately 20 xerographically printed reproductions in the same web length.

Heretofore, lthe usual practice has been to periodically remove the takeup roll with the paper web wound thereon to another location whcreat the paper was unwound and, with a manually operative cutter, cut the web so as to effect an approximate border on the leading and trailing edge of each xerographic print. By these former cutting means, considerable delay was incurred in effecting availability of the xerographic reproduction and, furthermore, required the services of additional personnel employed for this specific function.

Because of the variable occurrence of the cut on the moving web, it is preferable that a cutter mechanism be responsive to a reference means on the web. ln order for the cutter to respond in spaced relation to the reproduction, the reference means should emanate from relation of the original document to be reproduced whereby this relation is carried forth to the reproduction on the support surface. When, as here, it is intended to cut the web in relation to both the leading and trailing edge of reproduction, the reference means should be assocated with its respective edge in order that the cutter be made to respond accordingly, that is, to cut the web in advance of a leading edge and after a trailing edge.

The principal object of this invention is to improve xerographic reproduction apparatus for marking and cutting a web type of surface on which xerographic reproductions are formed.

It is a further object of the invention to form electrostatic latent image control patterns on a xerographic plate in relation to electrostatic latent images corresponding to the positioning of original documents to be reproduced.

These and other objects of the invention are attained by the apparatus herein disclosed and will be apparent from the following description.

A preferred form of the invention is shown in the appended drawings in which:

FIG. 1 is a schematic side elevation of an automatic xerographic printer employing the apparatus of the invention;

FIG. 2 is a view illustrating the marker apparatus of the invention in relation to the xerographic drum; and

FIG. 3 is a schematic diagram of the control circuit for the present invention.

Referring to FIG. 1, the paper web cutter assembly of the invention, generally designated as 10, shown in operative relation to a xerographic unit, generally designated as 12, which includes a xerographic plate in the forrn of drum 14 mounted in suitable bearings in the frame of the machine, and is rotated at constant rate by motor 16. The drum comprises a photoconductive surface 18 on a conductive backing that is sensitized prior to exposure by means of a screened corona charging device 20, which may be of the type disclosed in Walkup Patent 2,777,957, that is energized from a suitable high potential source.

Exposure of the drum to the light image emanating from an original document discharges the photoconductive layer in the areas struck by light, whereby there remains on the drum an electrostatic latent image correspending to the light image projected. To project an opaque original onto surface 18, a scanningy apparatus 22 is employed which may be of a type disclosed in Patent No. 3,105,425, granted to Cerasani et al. An original to be reproduced is manually fed from a support tray 24 onto endless belts 26 which are continually moved at constant rate proportional to the rate or movement of the paper web 28 by a drive motor 30.

As an original document moves on the belts, it passes under a sight glass 32 whereat an optical path is established from which the image on the document is reflected from mirror 34, thence through an objective lens 36 to a mirror 38 through a variable width exposure slit 40 so as to be exposed normal to the xerographic surface 13. A lamp 42 serves to illuminate the original document under the glass 32 and also serves to emit light to a copy detection device 44 when there is a spacing between documents and in the absence of documents to be reproduced.

kAfter exposure, the image is developed by developing apparatus 46, which may be of the type disclosed in the above referred to Patent No. 3,105,425, in which a twocomponent developer material is cascaded over the drum surface 18.

` The support surface in the form of the paper web 28 is obtained from a supply spool 48, is fed over suitable guide and tensioning rolls and directed into surface contact with the drum in the immediate vicinity of corona generating transfer device 50. After transfer, the support surface is separated from the drum surface and guided through a suitable heat fuser S2, which may be of a type disclosed in Crumrine et al. Patent No. 2,852,651, whereby the powder image is permanently affixed to the support surface. Subsequent to the transfer of the image, any residual image on surface 18 is removed by fbrush cleaning with brushes 54 which are rotated by motor 56. The web 2.8 then proceeds through web cutter assembly 10, as described below.

In order to detect the reference leading and trailing edges of the original documents for effecting an electrostatic latent image control pattern on surface 18 therefrom, the detection device 44 has a photocell 60 which is adapted to receive light rays from the lamp 42 by reflection from an inclined mirror surface 62. Light thereby transmitted is received by the light-sensitive photocell 60 which is characterized by emitting an electrical signal on the realization of light, wherein the magnitude of the signal varies in accordance with the intensity of illumination realized. In' the preferred arrangement, the signal emitted decreases in order of magnitude when there is an obstruction in the illumination path, such as the presence of documents on the belts 26, and increases in order of magnitude when no obstruction exists. As an original document moves on .belts 26, the leading edge thereof effects an obstruction of `the illumination path causing cell 60 to emit a low level signal output and, when the document trailing edge moves out of the path, the signal produced by the photocell is of a higher level.

An electrostatic latent image control pattern is formed on one end of the drum surface 18, axially spaced from the adjacent edge of the document image. To produce the pattern, almarking device in the form of a corotron 64 is operated by the detection of the detection device 44. The coro-tron 64, as shown in FIG. 2, includes a cylindrical shield 66 closed at its upper end by an insulation disc 68 which supports a corotron electrode 70 at the center thereof. The lower end of the shield 66y is bent inwardly to form an opening '72 through which corona discharge, caused by the presence of a high electrical potential on the electrode 70, will be directed upon the drum surface 18. Preferably, the opening 72 is square-shaped in order 4to produce a square-shaped, charged control image on the surface 18. The electrode, which is in the shape of a rod having a pointed discharge end, is positioned along the axis of the opening 72 and spaced therefrom to produce an image approximately twice the size of the square opening 72. As shown in FIG. l, the corotron 64 is positioned a short distance from the exposure slit 40 in the direction of rotation of the drum in order to permit energization of the corotron immediately after the adjacent portions of the surface 18 have been discharged by exposure to the light images of a document being scanned.

By the marker apparatus thus described, electrostatic latent image control patterns are formed on a xerographic plate which subsequently are developed and transferred to the support surface 28 and translated therefrom as a signal to effect subsequent cutter operation. Whereas the signal produced is described herein with particular reference to effect operation of a cutter apparatus, it is apparent that the marker apparatus could be employed to effect marking signals for other purposes, as, for example, to fold, punch, or other related operations in reference to a point on the web, or xerographic reproduction. Furthermore, although particular emphasis is placed on effecting control patterns in a particular relationship with the leading and trailing edges of xerographic reproductions, variations in apparatus arrangement Vwould perm-it effecting control patterns in any relation thereto.

- The web 18 is continuously drawn from the supply roll 4d and advanced through the paper cutter assembly It) by the motive force furnished from a motor '76. The force therefrom is transmitted through a suitable speed reducer and drive system, not shown, to drive a platen roller '78 under which the web 28 is in contact. rlhe web passes ,between two rollers 80 as it is driven by the roller 7-8. Further description of the web drive mechanism, which is described in detail in Patent No. 3,105,425, is not necessary for understanding of the present invention.

As the web passes Ibelow a detector means 82, the area thereof, on which the developed pattern marks corresponding to the latent control images produced by the corotron 64 for the leading and trailing edges of a document appear, is illuminated by a suitable lamp. As the pattern mark, corresponding to the leading edge of a document, passes into view under the detector means 82, it is projected through a lens system S6 and into a photocell 8S which immediately emits a `change in electrical signal induced through the electric circuit means shown in FIG. 3. At the detection of the pattern mark passing out from under the detection means 82, another change in electrical signal is emitted by the photocell S8 constituting a trailing edge signal.

As the web 28 passes the detector means 82, 4it moves between a knife member 90, normally in an ineffective position, and a bed plate 92 of the knife or cutter assembly, generally designated as 10. A pair of solenoids 96 mounted on the assembly 10 have their plungers connected to the knife member for actuating the same when energized for cutting Athe web 28. After cutting, when the solenoids are deenergized, the knife member is raised out of operative condition by a suitable spring, not shown.

`In operation, all the components of the xerographic unit 12 are in their operating condition. The corona generating device 20 is continually applying a uniform electrostatic charge lon the surface 18 and, in the absence of an original document, the corotron 64 is deenergized due to unobstruction of the light rays from lamp 42 to the photocell 60. The developing apparatus 46 is continually cascading developing powder over the'surface le and the web 28 is continuously moved between corona generating device Sti and the surface 18, through the fuser 52 and through cutter assembly 10, as aforesaid.

Referring to FIG. 3, positive rectified direct current is obtained from the part of the circuit generally outlined as itl@ and negative rectified direct current is obtained from the part of the circuit generally designated as T162. Switches S-ll, S-Z, and S-S are mechanically coupled to be actuated in unison and may be set to coincide at any of a number of optional positions of control. For discussion purposes, it is assumed that all of the switches have been set to effect cutting of the web 28 on the leading and trailing edges of a Xerographic reproduction.

Referring to FlGS. l and 3, documents to be reproduced are first fed from support tray 24 onto moving belts 26. As a document is moved thereon, the leading edge of the document traverses the light rays from the lamp 42 and, in eifect, obstructs the illumination pat-h between the lamp and the pihotocell 60. This decrease Iin illumination, in effect, `decreases the electrical sign-al reaching pentode V-S 4and activates this tube to a bias below cut-off so as to deenergive Ia relay ICR. Tihis has the effect of opening the switch lCR-l thereby ideenergizing relay 2CR and permitting normally closed switch ZCR-l to cause the energization of the corotron 64.

After exposure of the document by means of the lens system 34, 36, 33, at the instant the trailing edge of the document has passed ove-r the glass plate 32 so as to readmit light from the lamp 42 to cell 60, there is an increase in the signal emitted by pihotocell 60 Whichactivates the grid of pentode V-S above cut-off, thereby energizing relay lCR and consequently the relay ZCR -so as to effect opening of normally closed switch ZCR-l. Opening of the switch ZCR-ll causes dee-ner-gization of the corotron 64.

While the corotron is energized, a peripheral charged latent line image is formed on the surface 18 adjacent the edge of the latent image of the document. As succeeding documents are fed onto the belts 26, each leading edge obstructs the illumination path from lamp 42 to photocell 60 and again efects the energization of the corotron 64 to produce a latent image control pattern for each of the documents. The alternating energization of the corotron 64 eiiects an electrostatic latent ima-ge control pattern commencing and terminating in spaced relation on surface 1S corresponding in length between the leading and trailing edge, respectively, of successive original documents., The-latent images of the documents and the latent image control patterns are then xerographically developed, transferred and lixed in `the same spaced relation on the, support web 2S, as previously stateid The surface are-a on web 28 occupied by the Xerographic control pattern mark may be continually illuminated by suitable lamps, not show-n, and, at the detection of the beginning of a pattern mark or the detection of its termination, .as sensed by detector means 82, a change in electrical signal is emitted by the photocell 88. On detection of the pattern mark, which causes a decrease in illumination to the photocell 88, the change of signal emitted decreases and corresponds to the leading edge signal whereas on detection of the termination of the mark there is a-n increase in illumination at photocell 88, and the signal emitted increases to correspon-d rto the trailing edge of the document.

On detection of a leading edge signal, the decrease 4in the signal produced by the photocell 88 is transmitted through amplier circuit 164 and differentiating circuit 106 and through a triode V-7B to energize relay ECR through nonrnally closed switches 1LS-2 and 4CR-2 and thereby .close switches SCR-1 .and SCR-2. Closing of the switch SCR-1 forms a holding circuit through a triode V-8B, and the closing of the switch SCR-2 ener-gizes the timing clutch 110 of a timer 112 through a normally closed switch 1TR-1 to start a ytiming cycle. When the timer 112, Ihaving a preset time delay, times out, it causes energization of a relay 4CR .and the solenoids 96, closing of the switches 1TR-2 and 1TR-3, and opening of the switch 4CR-2. Energization of the solenoids 96 causes descending of the knife 90 to cnt web 28 in spaced relation to a leading edge of a Xerographic reproduction. As the cutter completes its downward stroke, some part thereof engages microswitches ILS-1 and ILSeZ thereby opening their normally closed contacts. Since the relay 4CR ,and the solenoids are energized by 'timer 112, the contact switches of 4CR-2 are opened as the knife 90 completes its downward stroke and the holding circuit of relay 3CR is opened by the opening of the ILS-2 Which deenergizes the clutch 110. This action restores the timer 112 to its original condition, deenergizes the solenoids and releases the relay 4CR. As the solenoids 96 are deenergized, suitable springs (not shown) actuate the knife 90 to its upper ineffective position.

On detection of a trailing edge signal which occurs at the end of the pattern mark, a signal from the photoccll 88 is applied to the Igrid of a triode V-7A and thereafter is transmitted through the amplifier circuit 104 and the differentiating circuit 116 to effect energizing of a -relay ZCR through the normally closed switches of 1LS-1 and 5CR- 2. Contact 2CR1 of the relay 2CR is closed to Iform a holding circuit through V-8A whereas the Contact 2CR-2 energizes the clutch 118 of a timer 120, having a preset timer relay, to start fa timing cycle. When the timer switches 2TR-2 and 2TR-3 are actuated, they energize a relay SCR and the solenoids 96 of the cutter causing descending of the knife to cut web 28 in spaced 4relation to a trailing edge of a xero-graphic reproduction. As the cutter completes its downward stroke, .a portion thereof actuates microswitches 1LS-1 and ILS-2 thereby opening their normally closed contacts. Since ythe relay SCR and the solenoids .are energized by timer 120, the normally closed contacts SCR-2 are opened as the knife completes its downward stroke and the holding circuit of relay ZCR is opened by ILS-1 to effect release. Opening of ZCR-Z deenergizes the clutch 118 restoring timer 120 to its origi nal condition and deenergizes relay SCR and the sole noids. As solenoids 96 Iare deenergized, the knife is restored to its upper ineffective position as before. 'Ihe purpose for the timers 112 and 120 is to cause a delay in the actuation of the cutter assembly 94 after detection by the detector 82 order to permit movement of the web 28 to the position below the knife 90. The timing cycles for both timers are identical and are of such a duration, based upon the speed of the web and the distance be. tween the detector and the knife, that cutting will occur substantially at the beginning and .terminal points of the pattern mark.

By the apparatus thus described there is disclosed appa4 ratus for forming electrostatic latent image control pat terns on a Xerographic drum Vand apparatus to cut a continuous web in spaced relation to the leading and trailing edges of a xerographic reproduction printed thereon.

Since many changes could be made in the above construction and many apparently Widely diiferent embodiments of this invention could be made without departing from the scope thereof, it is intended that all matter contained in the drawings shall be interpreted as illustrative and not in a limiting sense. For instance, in the above description, the resultant control pattern is described as a continuous line having a length approximately equal to the length of the document being reproduced. The relay 2CR-1 which serves to cause energization of the corotron 64 may be Iactuated for a fraction of a second upon energization of the relay 2CR. This will produce a single square-shaped pattern mark for each of the leading and trailing edges of the documents being scanned.

What is claimed is:

A control dev-ice for use with a web cutting apparatus of an automatic xerographic printer having a Xerographic plate movable through a series of processing steps wlherein Ithe cutting apparatus is adapted to cut a moving web support surface in accordance with the leading and trailing edges of successive documents being Xerographically reproduced by the printer, said control device including:

a control circuit having a scanning device adapted for detecting the leading and trailing edges of successive documents when lthe same are respectively imaged upon the drum,

said circuit including means for producing .an electrical signal when a leading edge has been detected and a corotron positioned adjacent the drum,

said corotron being adapted to produce a charge pattern on the drinn in response to said electrical signal whereby the charge pattern will be arranged along with images of the documents on the drum,

said charge pattern being adapted to produce -a control pattern on the web support surface corresponding to each of the Xerog-raphic reproductions of the documents,

means for cutting the support surface,

detector means arranged in scanning relation to the web being adapted to detect the leading and trailing edges of said control pattern and produce signals in accordance therewith, and

`an electric circuit connected to said cutting mean-s and having means responsive to said signal for actuating said cutting element whereby the web support Inaterial is out at a point adjacent the leading and trailing edge of the Xerographic reproductions of the documents.

References Cited by the Examiner UNITED STATES PATENTS 2,919,170 12/ 1959 lEpstein 95-1.7 X 2,919,672 1/1960 Benn et al. 95-1.7 X 3,013,890 12/1961 Bixby 95-1.7 X 3,045,644 7/ 1962 SchWertz 95-1.7 X 3,105,425 10/ 1963 Cerasani 95-1.7

JOHN M. HORAN, Primary Examiner. EVON C. BLUNK, Examiner.

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