US3410551A - Sheet separator - Google Patents

Description

Nov. 12, 1968 E. TIGER ET AL 3,410,551

SHEE TTTTTT 0R M kid lu A 37 NNNNN RS: 38 39 24 5 EM IGER ER E G. AN 33 KENNET R CK 3| BY I 32 I I \Lz W Nov. 12, 1968 E. TIGER ET AL 3,410,551

7 SHEET SEPARATOR Filed March '7, 1966 2 Sheets-Sheet 2 INVENTORS: EMIL TIGER ERSKINE G. CORMAN 'if ENNETH R. REICK ATT'YS United States Patent 3,410,551 SHEET SEPARATUR Emil Tiger, Highland Park, Erskine G. Corman, Forest Park, and Kenneth R. Reick, Downers Grove, 1th., assignors to Formfoto Manufacturing Company, Addison, 111., a corporation of Illinois Fiied Mar. 7, 1966, Ser. No 532,396 6 Claims. (Cl. 271--64) ABSTRACT OF THE DISCLOSURE A sheet separator for an electrostatic copying machine or the like wherein the original and copy are fed together into the machine in generally aligned fashion-particularly as to the leading edges. The separator includes an electromechanical arrangement in which two rollers coact to develop a shingling of the sheets by temporarily retarding one sheet through braking one of the rollers. This causes the retarded sheet to hump and the humping is utilized to release the braked roller. The shingled sheets thereafter pass through the nip between the rollers and are separated by a second roller set.

Background of invention The invention finds particular utility in connection with a wet process wherein the copy, after being exposed to the images carried by the master, is subsequently developed by immersion within a fluid reservoir. In the past, this has required that the two sheets, is. the master and copy, be separated, and this has required either manual manipulation on the part of an operator, shingling of the sheets or special sheet material-such as having oversized copy sheets so as to facilitate mechanical separation. The prior are has not realized the ultimate in this fieldthe ability to separate substantially aligned sheets. The difficulty of paperseparation is substantially increased by the fact that in an electrostatic copier the sheets are attracted to each other by the electrostatic charges resulting from the procedure.

It is, therefore, a principal object of the invention to provide a novel arrangement for achieving the separation of sheets, more particularly those utilized in copy machines.

Other objects and advantages of the invention may be seen in the details of construction and operation set down in this specification.

The invention is described in conjunction with an illustrative embodiment in the accompanying drawing, in

which- 7 FIG. 1 is a perspective view of apparatus embodying the teachings of the invention, the apparatus being partially broken away to reveal certain details of construction;

FIG. 2 is a sectional schematic view such as would be seen generally along the sight line 2-2 applied to FIG. 1;

FIG. 3 is an enlarged fragmentary sectional view of the upper right-hand portion of FIG. 2 and showing the elements thereof in a certain initial stage of operation;

FiIGS. 4-6 are views essentially similar to that of FIG. 3 but showing the apparatus therein in subsequent stages of operation; and

FIG. 7 is a wiring diagram of the electrical circuitry and electromechanical elements associated with the apparatus of the remaining views.

In the illustration given and with particular reference to FIG. 1, the numeral 10 designates generally a casing for an electrostatic copy apparatus and which is intended for desk or table mounting. The unit is relice ati'vely compact and is characterized by an inlet slot 11 into which generally aligned superposed sheets are introduced for the purpose of copying. After the copying has been achieved, the original or master is delivered from the slot 12 (see the extreme upper right-hand portion of FIG. 1) for receipt on an integral platform designated 13. The copy sheet itself is returned through a discharge slot designated 14 in FIG. 1.

The general procedure for preparing a copy of a master can be appreciated from a consideration of FIG. 2, and for a generalized understanding of the overall operation of the electrostatic copy apparatus, the following is set down:

General description Referring to FIG. 2, the casing is again designated 19 and is seen to include a corona charging device generally designated 15. The corona charging device has an interior passage as at 16 through which the generally aligned sheets pass in order to receive an electrostatic charge which is required for electrostatic copying. A corona charging device suitable for this purpose is shown and described in our co-pending application, Ser. No. 503,773, filed Oct. 23, 1965, and reference may be had thereto for additional details.

For advancing the aligned sheets M and C (see FIG. 3) an interior frame 17 (see FIG. 2) supports two sets of pull rolls 18 and 19, and 20 and 21. These rolls serve to advance the aligned sheets along a path which first includes the passage 16 of the corona device 15. The rolls 1821 are rotated by means of a motor M (see FIG. 7) and a chain linkage system to be described in greater detail hereinafter.

Thereafter, under the influence of the pull rolls 20 and 21 and a different set of pull rolls 22 and 23, the aligned sheets are passed through an illumination means generally designated 24 (see also FIG. 7) and which includes essentially a source of light so as to pass rays of light through the master M onto the electrostatically-charged copy sheet C. The aligned sheets, after exposure, are separated according to the apparatus to be described hereinafter, with the master issuing through a passage 12a leading to the slot 12, while the copy C is directed into a reservoir generally designated 25 for development. A final set of pull roll-s 26 and 27 operate to advance the copy toward the discharge slot 14 while squeezing most of the developing fluid from the copy C. The specific separation procedure and apparatus will now be described, and with particular reference to FIGS. 3-6.

In FIG. 3, the aligned sheets M and C are seen positioned within the nip 2S defined by rollers 29 and 30. Roller 30 is a driven roller, while roller 29 is an idler. Rollers 29 and 30 are centrally annularly recessed as at 2911 and 30a to accommodate a switch 31 (see FIGS. 2 and 7). As the forward edges of the sheets M and C engage the blade of the switch 31, the same is moved slightly to the right in FIG. 3, energizing the solenoid 32 (see FIGS. 1 and 7) which stops the idler roller 29 by means of brake 32a coupled to solenoid 32 by link 32b.

As the idler roller 29 is stopped, the master M is caused to hump in the fashion seen in FIG. 4. This results from the continued advancement of the copy C under the influence of the continued rotation of the pull roller 30, while the master M is restrained by the lack of rotation in the idler roller 29. After a predetermined time, the hump M reaches the height seen in FIG. 4this stemming from the continued rotation of the pull rollers 22, 23 and 30-so that the hump portion M contacts and actuates a blade switch 33. The blade switch 33 (as will be described hereinafter relative to FIG. 7) releases the brake 32a associated with the solenoid 32, permitting the idler roller 29 to recommence rotation. This results in the shingled or offset effect of the two sheets, as is seen in FIG. 5. The hump M continues to exist, but, in effect, moves rearwardly of the leading portion of the sheet M as the latter is now advanced under the joint rotation of the rollers 29 and 30. Ultimately, the now-offset sheets M and C reach rolls 34 and 35 (see FIG. 5), these rolls having been stopped by virtue of actuation of switch 31.

As the leading edge of the sheet C enters the nip 36 defined by the rollers 34 and 35, the sheet C is caused to bulge or become displaced from its generally planar configuration seen in FIG. 5 to that seen in FIG. 6 and which is designated by the symbol C. This second bulging or bumping results in displacement of the leading edge M of the master so as to direct the master sheet M into the discharge passage 12a. The retardation of the sheet C continues until the bulge portion C is sufficiently great as to contact a switch blade 37 which is operative to restart the rolls 35 and 34 so as to direct the copy C to the reservoir where the electrostatic image is developed. A suitable reservoir is shown and described in our co-pending application, Ser. No. 503,064, filed Oct. 23, 1965, and reference may be had thereto for additional details.

It will be seen that the invention is advantageous in that no matter how carefully aligned the copy and master sheets may be at the outset, there is a quick and positive mechanical separation without the need for an intervening human agency. Ordinarily, a secretary or clerk will, in preparing sheets for copy work, generally align the same by tapping the leading edges on a desk or other surface so that, in the past, it has been quite diflicult to develop some kind of offset or shingling so as to facilitate mechanical separation. This normal tendency can be tolerated in the practice of the invention, and further is used to advantage because the copy sheet now can be exactly the size of the master.

Operation In the practice of the invention, the two generally aligned sheets M and C are advanced along a copying path through the corona device 15 and past the light source 24. Each of these may be electrically energized by the arrangement depicted schematically in FIG. 7. There, a plug 38 is adapted to be coupled to a source of and the machine is controlled by an ON-OFF switch 39.

Movement of the aligned sheets along the copy path is achieved from power derived from motor M which, like the light source 24 and corona device 15, is disposed across the lines L and L of the diagram of FIG. 7. The output of the motor M is delivered to a sprocket 40 (FIG. 1) which is coupled by means of a chain 41 to a driven sprocket b fixed to the driven roller 30. Directionproviding idler sprockets 42 and 43 are also seen in FIG. 1. From these, rotational power is delivered by a chain and sprocket system (on the hidden side of the device in FIG. 1) to the pull rolls 18-23 and 26 and 27.

These pull rolls 18-23 deliver the aligned sheets to the nip 28 defined by the rollers 29 and 30 which constitute a retarding means for one of the aligned sheets. The retarding action is initiated by engagement of the leading edges of the sheets M and C with the spring loaded blade of the switch 31. When the switch 31 is actuated-by sensing the leading edges, the switch delivers power to the solenoid 32. v

The solenoid 32 then acts to retract link 32b to engage brake 32a with the journal of idler roller 29, thus temporarily stopping the same. The cessation of rotation of the roll 29 results in a flexure or displacement, hereinbefore referred to as the hump M, which is then sensed by the switch 33 to limit the degree of flexing the sheet.

The actuation of switch 33 breaks the circuit to solenoid 32 (switch 31 still being in its current-delivering position by virtue of the fact that the sheet C in passing through the nip 28 toward rolls 34 and 35 continues to depress the sensing blade of switch 31). Thus, the switch 33 constitutes a control means for superceding the retardation 4 occasioned by the sensing of the position of sheets M and C by the switch 31.

It will also be seen that the rolls 34 and 35 constitute second retarding means for the now-offset sheets C and M as seen in FIG. 5. Further, we find it advantageous to provide a guide plate in the form of the plate 44 which insures that the offset sheets, particularly the sheet C, is directed into the nip 36, and further that the bulging that results from the leading edge of the sheet C being positioned within the nip 36 will occur in the direction shown in FIG. 6 and wherein the switch 37 is arranged for sensing the sheet flexure.

The rolls 34 and 35 are driven by motor M (see FIG. 7). At the outset of operation the motor M is operating due to flow of current through switches 37, 33 and 31. Thus, even before the aligned sheets enter the corona device 15, the rolls 34 and 35 are rotating and continue to do so until switch 31 is tripped by the leading edges of the sheets M and C. Thereafter, the rolls 34 and 35 stop until the second hump appearsto actuate switch 37. This re-enengizes motor M independently of switches 33 and 31. By the time this second hump M disappears, indicating the completion of the engagement of the trailing portions of the sheets M and C with the rollers 29 and 30, the switch 37 returns to its normal position shown in FIG. 7. This arrangement then results in delivering current to motor M through switches 31 and 33, these again being in their ready conditions due to the fact that the trailing portions of the sheets M and C are no longer able to actuate these switches. Switch 37, as it starts motor M also de-energizes solenoid 32 so that when hump M collapses at the tail end of sheets M and C, it will prevent the re-energizing of solenoid 32. If solenoid 32 was re-enerlgized by switch 33 when hump M collapsed roller 29 would stop again and prevent free delivery of the tail end portions of sheets M and C.

While in the foregoing specification, we have set down certain details for the purpose of explanation, many variations therein may be made without departing from the spirit and scope of the invention.

We claim:

1. A sheet separator, comprising a frame, means on said frame for advancing along a predetermined path a pair of relatively flexible sheets in surface contact and generally aligned relation, first means on said frame in said path for temporarily retarding one of said sheets relative to the other to provide the leading edge portion of said other sheet projecting forwardly in the direction of path advance, and second means on said frame in said path for temporarily retarding the leading edge of said other sheet, whereby a portion of said other sheet rearward of its leading edge is flexed generally normal to said path to project the leading edge of said one sheet out of said path, said first retarding means including roller means adapted to flex a portion of said one sheet in a direction generally normal to said path, sensing means on said frame responsive to the flexing of said one sheet for actuating said roller means to develop only a limited flexing in said one sheet.

2. The structure of claim 1 in which said first retarding means also includes switch means responsive to the generally aligned leading edges of said sheets, said roller means including a pair of rollers defining a nip, means on said frame for rotating said rollers, one of said rollers being adapted to contact said one sheet, the other of said rollers being adapted to contact the other sheet, said switch means being operatively associated with said one roller to stop rotation of the same in response to a predetermined position of said generally aligned leading edges, said sensing means also being operatively associated with said one roller to actuate the same by restarting rotation thereof.

3. The structure of claim 1 in which said second retarding means includes a pair of rolls arranged in sideby-side relation to define a nip, means on said frame for rotating said rolls, and switch means operatively associated lWith said rolls for stopping rotation thereof prior to entry into said nip of said other sheet leading edge, and sensing means responsive to said flexed portion to restart rotation of said rollers.

4. The structure of claim 3 in which said frame is equipped with a support for guiding said other sheet leading edge into said nip.

5. A sheet separator comprising a frame, roll means on said frame for advancing a pair of generally aligned contacting sheets into the nip defined by a pair of rollers, a pair of rollers mounted for rotation in said frame and defining said nip, means on said fname for rotating said rollers, means on said frame responsive to the position of said sheets relative to said nip for stopping the rotation of one of said rollers to create a fiexure, the one of said sheets contacting said one roller, sensing means adjacent said one roller responsive to the degree of flexure of said one sheet for re-starting the rotation of said one roller whereby said sheets are thereafter advanced with their leading edges in shingled relation, and means on said frame in the path of sheets leaving asid pair of rollers for temporarily retarding the leading edge of the more advanced sheet to eifect separation of the sheets.

6. The structure of claim 5 in which the other of said rollers is coupled to said rotating means, said one roller being frictionally driven by said other rollers, and brake means operatively associated with said responsive means for stopping the frictional drive of said one roller, said sensing means also being operatively associated with said switoh means for deactivating said brake trneans.

References Cited UNITED STATES PATENTS JOHN M. HORAN, Primary Examiner.

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