US3537703A

US3537703A - Manifold sheet separating device

Info

Publication number: US3537703A
Application number: US702898A
Authority: US
Inventors: James H Blow Jr
Original assignee: Xerox Corp
Current assignee: Xerox Corp
Priority date: 1968-02-05
Filing date: 1968-02-05
Publication date: 1970-11-03
Anticipated expiration: 1987-11-03
Also published as: GB1261077A; DE1904341A1; CA923351A; JPS542103B1

Description

Nov. 3, 1970 J. H. BLOW,-JR

MANIFOLD SHEET SEPARATING DEVICE 2 Sheets-Sheet 1 Filed Feb. 5} 1968 A T TORNEVS Nov. 3

J. H. BLOW, JR

MANIFOLD SHEET SEPARATING DEVICE 2 Sheets-Sheet 2 Filed Feb. 5, v 1968 INV JNTO JAMES H. BLSW JB.

ATTORNEYS United States Patent 3,537,703 MANIFOLD SHEET SEPARATING DEVICE James H. Blow, Jr., Rochester, N.Y., assignor to Xerox Corporation, Rochester, N.Y., a corporation of New York Filed Feb. 5, 1968, Ser. No. 702,898 Int. Cl. B65h 29/64 US. Cl. 271-18 4 Claims ABSTRACT OF THE DISCLOSURE This invention relates to a sheet separating device, and more particularly, to sheet separation of manifold imaging sandwich sets.

Particular use for this invention is found in an imaging system utilizing a manifold set comprising a photo-responsive material between a pair of sheets. In this imaging system, an imageable plate is prepared by coating a layer of cohesively wea-k photoresponsive imaging material onto a substrate. This coated substrate is called the donor. In preparation for the imaging operation the imag ing layer is activated as by treating it with a swelling agent or partial solvent for the material, or by heating. This step may be eliminated, of course, if the layer retains sufficient residual solvent after having been coated on the substrate from a solution or paste. The activating step serves to weaken the imaging layer structurally so that it can be fractured more easily along a sharp line which defines the image to be reproduced. Once the imaging layer is activated, a receiving sheet is laid down over its surface. An electrical field is then applied across this manifold set while it is exposed to a pattern of light and shadow representative of the image to be reproduced. Upon separation of the donor substrate or sheet and receiving sheet by apparatus disclosed herein the imaging layer fractures along the lines defined by the pattern of light and shadow to which the imaging layer has been exposed, with part of this layer being transferred to the receiving sheet while the remainder is retained on the donor sheet so that a positive image, that is, a duplicate of the original is produced on one sheet while a negative image is produced on the other.

At least one of the sheets is partially transparent to permit exposure of the imaging material to the image to be reproduced. The imaging layer serves the dual function of imparting light sensitivity to the system while at the same time acting as colorant for the final image produced.

The above results are accomplished by an imaging system utilizing a structure comprising a cohesively weak imaging layer sandwiched between a donor sheet and a receiving sheet. The imaging layer has initially a stronger degree of adhesion for the donor sheet than for the receiver sheet. After the imaging layer is activated by brushing a partial solvent on it, the sandwich of donor sheet, imaging layer, and receiver sheet is placed between tWo electrodes, at least one electrode being at least partially transparent. A charge is placed across the imaging layer and the image layer is exposed to light projected from an image to be reproduced. After imaging, the charge across the imaging layer is modified, for example, by reversing the potential bias of the electrodes. That is, if the receiver sheet side Was biased positive in resepct to the donor side of the manifold sandwich prior to imag- Patented Nov. 3, 1970 ing, the receiver sheet side would be biased negative in respect to the donor side after imaging. The sheets are separated in accordance with this invention during or subsequent to application of the reverse bias.

By reversing the field across the imaging layer, the images obtained on the receiver sheet and donor sheets are also reversed. It is, thus possible to provide a high quality positive image on opaque receiver materials. Alternatively, the manifold sandwich may be charged by passing the sandwich between electrodes, imaging, then passing the sandwich between electrodes charged to the opposite polarity to effect reverse imaging. For a more detailed disclosure of manifold imaging apparatus see copending application Ser. No. 609,058 filed Jan. 13, 1967 in the name of I. T. Krohn et al. and entitled Manifold Imaging.

The imaging layer may be exposed either through the donor sheet or the receiver sheet. Since exposure through the donor substrate allows the use of opaque receiver sheets, it is preferred to expose through the donor sheet. The light image may be formed by projecting light through a transparency or by projecting light information from an opaque subject.

It has also been found that certain imaging layers respond to reverse biasing without exposure to activating electromagnetic radiation. That is, initially the imaging layer adheres more strongly to the donor sheet than to the receiving sheet; however, by charging the set by applying a field across the set and then reversing the field across the set certain imaging layers are found to adhere more strongly to the receiver sheet than to the donor sheet. It is, therefore, possible to provide a system wherein the manifold set is given a uniform charge and then placed in an imagewise field of opposite polarity. Upon separation of the donor and receiver sheets the imaging layer fractures in imagewise configuration providing a positive image on one of the sheets and a negative image on the other. For these imaging layers then it is not necessary to provide photosensitive pigments dispersed in a binder; instead, pigments not considered photosensitive may be incorporated in the imaging layer. Typical of these pigments are carbon black, iron oxides, lead chromate in paste form designated alykyd paste, titanium dioxide, lead chromate, and the various pigments used in printing inks and mixtures thereof.

In addition, it has been found that certain exposed imaging layers will reverse images when grounded before separation and in some cases imaging layers respond to a reduction in field of the same polarity. That is, for certain imaging layers, if the manifold set is grounded or placed in a reduced field subsequent to imaging, those areas of the imaging layer which normally adhere to the receiver and donor sheets adhere instead to the donor and receiver sheets respectively.

In general, therefore, the steps of manifold imaging are to activate and close the manifold set, establish an electric field across the imaging layer, expose the imaging layer to imagewise electromagnetic radiation, modify the electric field across the imaging layer and separating the receiver and donor sheets. By modifying then is meant that the electric field across the imaging layer is either reduced, including grounding, or reversed.

The donor substrate and the receiving sheet may consist of any suitable insulating materials. Typical insulating materials are polyethylene, polyethylene terephthalate, cellulose acetate, paper, plastic coated paper, such as polyethylene coated paper and mixtures thereof. Mylar, a polyester formed by the condensation reaction between ethylene glycol and terephthalic acid, available from E. I. du Pont deNemours and Co., Inc., is preferred because of its physical strength and because it has good insulation qualities. Where imagewise exposure is projected through one of the electrodes, one electrode should be at least partially transparent. Any suitable transparent conductive electrode material may be used.

In automating the manifold imaging process it becomes necessary to separate the sheets before exit from the automatic machine making the manifold image sets. After separation, it is necessary to dry the manifold sheets to more or less fix the image for later handling.

It is therefore an object of this invention to improve sheet separation devices for automatic machinery;

Another object of this invention is to improve devices for separating and drying previously imaged manifold sheets;

Another object of this invention is to separate and dry manifold sheets and stack them in separate piles of negative and positive images.

These and other objects of this invention are accomplish by means of separation rollers to initially separate the driven manifold sheet sets and then drive them along separate paths. Also, drying means interposed in the path of movement of the separated sheets to fix the images thereon before exit from the apparatus in which they are imaged.

For a better understanding of the present invention as well as other objects and features thereof reference is had to the following detailed description of the invention to be read in conjunction with the accompanying drawings wherein:

FIG. 1 is a schematic representation of an automatic manifold imaging apparatus;

FIG. 2 is a schematic representation of a manifold set separating device; and

FIG. 3 is an isometric schematical representation of another separating device.

Referring to FIG. 1 there is shown a manfold set comprised of an insulator receiving sheet 12 and a donor substrate sheet 14 having dispersed therebetween a layer of cohesively weak photoresponsive imaging material composed of a binder with photosensitive particles therein and an activator fluid or partial solvent for the material 16. The two sheets and material therebetween are closed into a single cohesive sandwich, called the manifold set 10 by passing the combination through a pair of pressure rollers 18 or the like which seals the photoresponsive imaging material between the donor and receiving sheets. The combination may be formed such that a lead edge exists which consists only of the donor and receiving sheets without photoresponsive imaging material therein.

The manifold set passes through a charging station where electrode 20 places a negative charge on the donor sheet and electrode 22 places a positive charge on the receiving sheet. The charges may be reversed and images will still be formed. The set next passes a pair of pinch rollers 24 which maintains it on its path through the processing stations of the automatic apparatus. At the next operative station 26 a radiation pattern of electromagnetic radiation generally in the form of light rays is imaged through a lens 28 through the transparent donor sheet 14 of the manifold set. An image is formed by moving an object 30 past an illumination source 32 in timed sequence with the movement of the manifold set 10 through the pinch rollers 24 over a transparent platen 31. In this way a flowing image of the object 30 is placed on the manifold set to atfect a change in the charge pattern thereon and in the photoresponsive imaging material therein.

Pinch rollers 34 continue to drive the manifold set 10 to the next processing station where the manifold set is charged to a polarity opposite to the original polarity given by electrodes 20 and 22. Here electrode 36 places a charge opposite to that of electrode 20 on the donor sheet 14 of the manifold set 10 and electrode 38 places a charge opposite to that given by electrode 22 to the receiving sheet 12 of the manifold set. Pinch rollers 40 continue to move the set forward bringing the lead edge of the sheets to oppositely rotating separating

rollers

42 and 44. The roller 44 may be clutched or suitably driven to rotate in the same direction as rollers 40. At a predetermined time, roller 44 is rotated in the opposite direction, separating the sandwich layers.

The lead edge of the donor sheet 14 is pushed back by roller 44 and guided around the roller 44 forming a buckle between the non-image lead part of sheet 14 and that of sheet 12. As the set is driven further forward by pinch rollers 40, the lead edge of sheet 14- is driven around roller 44 and falls in the guide path between

bafiles

46 and 48 where it is continually forced forward by rollers 40. As it passes between

guide plates

46 and 48 it is acted upon by air flow from housings 50 and 52 until it comes to rest in donor copy tray 54.

Meanwhile, as sheet 14 is guided to donor sheet tray 54 the receiver sheet 12 is pushed by pinch rollers 40 and by the action of roller 42 over guide plate 56 and housing 58 where air flow is made to contact the sensitive surface of the receiver sheet. The sheet then continues with the aid of rollers 59 to receiver sheet tray 57.

Housings

50, 52 and 58 each have perforated face plates 61, 62 and 63 respectively. A fan pump, or other means causes a flow of circulation of air through and out of the perforations in the plates of the individual housings. In each housing is a heat source 60 that aids in warming the air in the housing for expulsion to the donor or receiver sheet passing in the vicinity of the air escaping from the housing. The heating element aids in drying the image layer formed in the receiving and donor sheets. It is preferable to maintain the air flow at a velocity sufficient to prevent the image sides of the sheets from touching the guide plates or housing portions in the path of the sheets. This aids in preventing smearing or smudging of the image before it is dried and fixed.

The electrodes used for charging the donor and receiver sheets can be of any type that would create a charge layer on the sheets. Therefore, a corotron could be used for each of the electrodes. The second electrical field placed on the manifold set by electrodes 36 and 38 can be eliminated as can the drive rollers 34 and an image could still be formed. The image however would be the reverse as far as negative and positive imaging of the images on the donor and receiver sheets as described herein. Also, a reversal of all of the charges on the electrodes will image manifold sets of certain materials better than with others. This invention, however, is not concerned with the material used for the manifold set including the particular photoreceptive layer used. Pinch rollers 34 and electrodes 36 and 38 can be eliminated from the processing and an image will still be formed on the image layer of the manifold set. Nevertheless, the embodiment described presents a preferred arrangement of processing steps.

FIG. 2 schematically shows one method of initially separating the two sheets of the manifold set including a set of drive pinch rollers 40 rotating to move the manifold set 10 to the separating

rollers

42 and 44. The roller 42 rotates in the same direction as the drive rollers 40 where as 44 rotates counter to the direction of roller 42. The roller 44 is maintained in close proximity to roller 42 such that when the lead edge of one of the sheets 14 of the manifold set 10 passes between the

rollers

44 and 42 roller 44 causes the lead edge of the sheet 14 to move back along the original path of drive. However, sheet 12 will continue to be driven by

rollers

42 and 40 and in a direction approximating that which it has when it leaves pinch rollers 40 since the friction between the sheets is less than that between the roller and a sheet. After the contact of the lead edge of sheet 14 by roller 44 and the subsequent forcing of a buckle in sheet 14 because of the opposite direction of drive between the rollers 40 and the roller 44, the roller 44 is moved out of contact of the sheet 12 which continues in its path through the nip between

rollers

44 and 42. The roller 44 first drives sheet 14 over itself and onto a new path as directed by

guide plates

40 and 46 before it separates from the roller 42. The sheet is driven past housing 52 where heated air is forced through perforations in the housing face plate 62 thereby drying the portions of the image remaining on the sheet 14. The roller 44 is axially moved by a mechanism schematically shown as a cam 68 contacting a follower 69 shafted to the center axis of roller 44 by a shaft 70. A biasing means such as a spring 73 provides intimate contact between the cam 68 and the follower 69. As the cam rotates, it causes a closing of the nip between roller 44 and the roller 42 in timed relation with the passage thereat of the manifold set 10. After the contact by roller 44 of the lead edge of sheet 14, the cam continues to rotate pulling roller 44 away from roller 42 bringing with roller 44 the lead edge and the remainder of the sheet 14. The movement is controlled so that sheet 14 has buckled on its lead edge flipped over roller 44 when roller 44 separates from its contact position. A photocell or limit switch 71 can be strategically interposed in the path of travel of one or both sheets and connected to a cam control energization unit to operate the cam 68 and thereby control the nip between

rollers

42 and 44.

FIG. 3 schematically shows another method of achieving the separation of the sheets of the manifold set by providing belts to check the path and maintain the motion of the manifold set coming therethrough. Belt 72 rotates in the same direction as the rest of the drive mechanism pushing the manifold set through the system. Belt 74 is rotated by its rollers 76 and 78 in a path counter to the movement of the belt 72. Belt 74 has small fingers 80 thereon which help engage the lead edge of the sheet contacting them. As the sheet buckles and flips over the belt 74 due to the driving forces explained above, the belt 74 is pulled away from belt 72 bringing with it the lead edge and the remainder of the sheet 14. The shift of the belt 74 is accomplished by a solenoid 82 operating in timed relation to the flow of manifold sets through the processing apparatus.

While the invention has been described with reference to the structure disclosed herein, it is not confined to the details set forth, and this application is intended to cover such modifications or changes as may come within the purpose of the improvements or the scope of the following claims.

What is claimed is:

1. Sheet separating apparatus for use with a manifold set having two weakly bonded sheets, the apparatus comprising:

means for moving the manifold set along a predetermined path first and second urging means interposed on opposite sides of the path and each spaced to contact one of the sheets as the same passes the point in the path where said urging means is positioned,

drive means operatively connected to each of said urging means for providing counter motion of each to the other at the path of movement of the manifold set,

said first and second urging means being positioned in close proximity to each other at the path of movement of the manifold set to each engage a sheet of the manifold set, one of said urging means forcing the sheet it contacts to depart from the motion caused by said moving means and the other of said urging means urging the other sheet of the manifold set to maintain substantially the same motion caused by said moving means,

said drive means providing counter motion on said urging means for at least a time sufficient to separate the leading portions of the sheets of the manifold set and cause one of the sheets to change its path from the other of said sheets,

wherein said first and second urging means have further associated therewith hairlike protrusions on the surface thereof to contact the lead edge of the sheets of the manifold set to aid in separation of the sheets.

2. Sheet separating apparatus for use with a manifold set having two weakly bonded sheets, the apparatus comprising:

said drive means providing counter motion on said urging means for at least a time sufiicient to separate the leading portions of the sheets of the manifold set and cause one of the sheets to change its path from the other of said sheets,

wherein said first and second urging means comprise transport members, a one of said transport members being reciprocating and having operatively associated therewith bias means to maintain said reciprocating transport member in a first position separated from the path of the sheets,

sensing means to determine the presence of a sheet,

and

means responsive to said sensing means to move said reciprocating transport member against the action of said bias means to a second position in the path to cause contact with the aforementioned sheet of the manifold set moving through the path during counter motion of said transport members and to maintain said reciprocating transport member in the second position until the sheets of the set are separated.

3. The apparatus of claim 2 wherein said means responsive to said sensing means is a cam and cam follower operatively connected to said reciprocating transport member.

4. The apparatus of claim 2 wherein said means responsive to said sensing means is a solenoid operatively connected to said reciprocating transport member.

References Cited UNITED STATES PATENTS 3,044,769 7/ 1962 Breuers 271-18 3,285,603 11/1966 Boston et al 271-64 XR 3,297,317 1/ 1967 Stievenarti 271-64 3,348,839 10/1967 Stievenart et a1 271-64 3,352,554 11/1967 Menzi et al. 271-64 EUGENE R. CAPOZIO, Primary Examiner PAUL V. WILLIAMS, Assistant Examiner US. Cl. X.R. 270-52; 271-64