US3463584A - Photocopying machine - Google Patents

Description

' c. TRoMBE'rrA PHOTOCOPYING MACHINE 3 Sheets-Sheet l Cnzlfo Rom BC- rrn @MMM/1m @um www Aug. 26, 1969 original med Dec. `s. 1964 Aug. 26, 1969 C. TROMBETTA 3,463,584

PHoTocoPYING MACHINE original med ogg. s. 1964 5 Sheets-Sheet 2 m E LA..

C. 4E/.o 7 Edin Bien-ra SWW Aug. Z6, 1969 c. TROMBETTA 'PHo'rocoPYING MACHINE' s sheet-sasha s Original Filed Dnc, 3, 1964 m r .c m9,* W o am n o L R .lllllio m C m x m z DDE n J am: Nm Nm w wu z A mm u J ami United States Patent O U.S. Cl. 355--3 1 Claim ABSTRACT F THE DISCLOSURE The electrophotographic copying machine has means for feeding a document along an illuminated exposure path, and an upper slightly depressible table for receiving the document for insertion along an aligning margin guide into the illuminated path. Means, responsive to the insertion of the document, feeds a copy sheet along the exposure path. The device further has means for electrostatic charging the copy sheet, means for illuminating the document, means for developing the image, means for fixing the image, and an electrical switch responsive to depression of the table for energizing the various means. A feeler mounted in the above mentioned path and responsive to the passage of the trailing edge of the document deenergizes the above mentioned means.

This application is a division of my application Ser. No. 415,681, filed Dec. 3, 1964.

The present invention relates to a photocopying machine for reproducing, for instance according to an electrophotographic process, a document fed along an illumination path onto a copy sheet fed in synchronism with said document along an exposure path.

A photocopying machine of a first type is known, wherein said copy sheet is automatically picked-olf from a sheet supply stored inside the machine. In a known machine of a second type the copy sheet is automatically cut from a paper roll stored inside the machine whereas in a known machine of a third type the copy sheet is manually introduced into the machine along with the document.

A greater operation flexibility is achieved in a photocopying machine of a fourth type, wherein said sheet may be either manually introduced from outside or automatically cut from a roll. However, concurrently inserting by hand both the copy sheet and the document is a tedious and inaccurate operation.

Furthermore, in the aforesaid photocopying machines exact al-ignment of the document with respect to the feeding direction can not be easily obtained; the form of the paths for the copy sheet and for the document and their relative location are such as to entail vastage of space and the electrical circuits controlling the machine are expensive and subject to failure because a great number of electromagnets and electrical contacts are used therein.

Accordingly, it is an object of the present invention to provide a photocopying machine having fully automatic operation.

Another object of the present invention is to provide a photocopying machine which is easily adaptable to different operation modes.

Another object of the present invention is to provide a photocopying machine ensuring accurate alignment of the copy with respect to the original document.

Another object of the present invention is to provide a photocopying machine of the electrophotographic type which is extremely compact.

Patented Aug. 26, 1969 ice Still another object of the present invention is to provide a photocopying machine wherein insertion of the document to be copied, proper alignment of said document and activation of the machine can be accomplished with a single and simple operation.

Still another object of the present invention is to provide a photocopying machine wherein control of different function and preselection of different operation modes are accomplished by a novel combination of mechanical and electrical means which allow circuit failures to be prevented while minimizing the number of parts.

These and other objects are accomplished by the photocopying machine according to the invention, which is characterized in that under the control of a two-position selector said copy sheet is fed into said exposure path either by picking-off from a sheet supply or by outting from a roll, a device under the control of a documentsensing feeler being conditioned by said selector in its first position for causing said copy sheet to be picked-olf from said supply upon sensing the leading edge of said document and being conditioned by said selector in its second position for feeding said copy sheet from said roll into said exposure path upon sensing the leading edge of said document and for cutting said copy sheet from said roll upon sensing the trailing edge of said document.

Other objects, features and advantages of the invention will be apparent from the following description of a preferred embodiment thereof, in connection with the accompanying drawings, wherein:

FIG. l partially shows a vertical section of the machine according to the invention;

FIG. 2 partially shows another vertical section of the machine parallel to the section of FIG. 1;

FIG. 3 shows the electrical circuit diagram of the machine according to the invention;

FIG. 4 is a perspective view of the machine according to the invention;

FIGS 5a and 5b are time diagrams of the operation of the machine according to the invention.

With reference to FIGS. l and 4, the photocopying machine according to the invention comprises an upper table 1, whereon the document to be copied is placed for being introduced into an opening 2 which is the entrance of the illumination path.

The document may be laterally pushed with its righthand edge abutting the aligning margin guide 3 in order to obtain an exactly oriented copy. Thereafter the document is manually pushed -into engagement with a first pair of feeding rollers 4, 5, which are a part of a document feeding apparatus generally designated with the reference number 6 and located in the back portion of the machine. The upper table 1 is rotatably mounted on an horizontal axis coincident with its left-hand border in FIG. 1. When pushed to rotate downward against the action of a spring not shown in the drawings, table 1 actuates an electrical switch MSP. Switch MSP when actuated energizes, inter alia, the document feeding apparatus 6. Therefore, it is apparent that the arrangement of the entranceZ over the upper table 1 allows the document to be introduced without being sustained by the operator as required in the known photocopying machines; that more accurate lateral alignment of the document than in said known photocopying machines may be achieved, and that the machine may be started while inserting the document in a unique and simple operation.

The document feeding device 6 comprises a pair of lateral plates 7 supporting for rotation therebetween three motor rollers 5, 9, 10, which are continuously rotated by a motor M not shown in FIG. 1 through a gearing box 12 located at the right-hand side of the machine. Motor rollers cooperate with driven rollers 4, 14, 15, 16, 17, 18. 'Ihe illumination path for the document to the copied comprises the document guide 8, the pair of rollers 4 and 5, the pair of document guides 19 and 20, the pair of rollers 9 and 14, the pair of guides 21 and 22, the pair of rollers 10 and 15, the guide 23, the pair of rollers 10 and 16, the guides 24 and 25, the pair of rollers 9 and 17, the pair of guides 26 and 27 of an illumination station 29 and the pair of rollers 5 and 18.

Guide27 is transparent to the light radiated by a lamp L and reflected by a reflector 32, whereby the reflected image of the document is projected through a lens vsystem 33 and a mirror 34 onto the photosensitive copy sheet which is simultaneously present in an exposure station 35.

A deflector 30 may be preset, by means of a knob not shown in the drawings, in a single copy position indicated with continuous lines in FIG. 1, wherein its surface 36 is able to guide the document out of the illumination station 23 onto a document receiving plate 31, from which the copied document may be thereafter extracted by the operator. For this purpose a lateral opening 11 (FIG. 4) is provided in the upper table 1 to help extracting the copied document from plate 31.

Alternatively, the deflector 30 may be counterclockwise rotated on the pivot 61 by means of said knob so as to be preset in a multiple copy position, wherein its surface 38 cooperates with motor rollers 5 to reintroduce the document into engagement with the initial pair of rollers 4, of the illumination path .as it comes out of the illumination station 29 through the last pair of rollers 5, 18 of said path.

Therefore, when dellector 30 is in this multiple copy position, the document is caused to repeatedly travel the illumination path in order to obtain a plurality of copies, while the edge 37 of the deilector 30 prevents erroneous insertion of a new document.

The document feeding appartus -6 may be removed from the machine so as to allow inspection and removal of any document trapped therein. For this purpose the two lateral supporting plates 7 of the feeding apparatus 6 are supported for limited rotation on studs 28 fixed ot the frame of the machine.

The photosensitive copy sheet may be conveniently made of a paper substrate covered with a photoconductive layer comprising for instance zinc oxide finely dispersed in an insulating binder.

The exposure-path of the copy sheet comprises a charging station 39, wherein an uniform electrostatic charge is deposited on the photoconductive layer of the copy sheet; an exposure station 35 wherein the light reflected from the document to be copied is projected onto the photoconductive layer, so as to reduce its electrostatic charge in the illuminated areas, whereby on said photoconductive layer a latent electrostatic image of the document is produced, a developing station 40 wherein a developing powder is carried into contact with said photoconductive layer, so that said powder adheres to the areas of said layer corresponding to the dark areas of the document from which the electrostatic charge had not been removed, whereby a powder image of the document is obtained on the sheet; and a xing lstation 41, wherein said powder forming the developed image is fused so as to be perma nently fixed to the sheet.

The copy sheet is driven along said path by means of three pairs of feeding rollers 89 and 90, 91 and 92, 93 and 94, the rollers 89, 91 and 93 being motor rollers geared to the motor M.

Under the control of a two-position selector, for instance a sheet-roll preselection knob described later, either a copy sheet pick-olf from a sheet supply 43 or a copy sheet cut from a photosensitive paper .roll 44 may be fed into the exposure path.

The sheet pick-off mechanism comprises a sheet pickoff roller 53, whose initial inoperative position is indicated to reach a final position indicated by dotted line-s in FIG. l, so as to frictionally drive the upper sheet of the ream 46 between a pair of guides 47 and 48 and into engagement with a pair of feeding rollers 49 and 50.

To this end the sheet pick-off roller 53 is connected to an arm 54 pivoted on a crank 55 which can oscillate around an axis 56 xed tothe machine frame. An extension 57 of crank 551s provided with a cam follower 58 cooperating with a cam 59 fixed to the driven part of a single-revolution clutch 62, whose motor part is permanently geared to the shaft of the motor M. When clutch 60 is Vactivated in a manner to be described later, cam 59 is caused to make a complete revolution and then stop, whereby roller 53 is caused to make a complete stroke from the inoperative position to the iinal position to pick-off a sheet and then to return to the inoperative position.

The photosensitive paper roll 44 is wound on a roller 63 journaled between a pair of lateral plates 64. Paper roll 44 can be removed because the roller 63 is supported in fork-shaped openings of said plates. v

Lateral plates 64 and a crosspiece 65 joining said plates form acontainer for the paper rolland are a part of, a carriage which can beextracted from the left-hand side of the machine. For this purpose the crosspiece 65 of the carriage is provided with a series of rollers 66 and 67 movable on guides 68 and 69 which in turn can move on a series of rolls 70 and 71 journaled on a fixed part 72 of the machine frame. When extracting the carriage, also the guides 68 and 69 are extracted to support the carriage itself, suitable stop members being provided to limit their Ntravel to an extent equal to about one half the travel of the carriage.

A pair of arms is rotatably mounted on studs 76 which are fixed respectively to the two lateral plates 64 of the paper roll bearing carriage. A pair of paper feed rollers 73, 74 is journaled between arms 75. By rotating the roll-sheet selecting knob, the arms 75 may be set in a roll position, wherein roller 73 is urged against roller 49 driven by a continuous clutch 52 having its motor part geared to the motor M, whereby when clutch 52 is engaged to rotate roller 49, the rotation of roller 49 is transmitted to the rollers 73 and 74 to feed paper 42 from roll 44 toward the charging station 39. Alternatively, the arms 75 may be preset in a sheet position, wherein the pair of rollers 73, 74 is raised, whereby feeding the paper 42 from roll 44 is inhibited, as the roller 73 does not engage the motor roller 49.

When the paper roll bearing carriage is laterally extracted for loading a new paper roll, the roll-sheet selecting knob is in the sheet position. Under these conditions, before reintroducing the carriage into the machine the free end of the paper roll can be easily inserted lbetween driving roller 73 and roller 74, spring urged .against it.

In order to cut from roll 44 a paper sheet having a length corresponding to the document length, a cutting device is provided comprising a lower fixed blade 78 and an upper movable blade 79 pivoted at one end on the machine frame and at the other end to a vertical rod 80, which in turn is pivoted to a crank 81. Crank 81 is lixed to the driven part of a single-revolution clutch 82 having its motor part permanently geared to the shaft of the motor M. y

The charging station 39 comprises an upper electrostatic shield 83 and a lower electrostatic shield 84, which are electrically connected to ground and surround a pair of negative wires 85 and a pair of positive wires 86 respectively, said wires being. horizontally supported so as to extend over the entire width of the paper sheet passing between said shields. By means of a circuit to be described later a corona discharge is produced between wires 85 and wires 86 to negatively charge the photoensitive face of the sheet with respect to its opposite ace.

Between the charging station 39 and the pair of feeding rollers 89, a roller 95 is rotatably supported in a slit 96 of the machine frame to cause by its weight the sheet to form .a loop for preventing rollers 89, 90 from tearing the sheet when cutting blade 79 is operated.

The exposure station 35 comprises a backing paper guide 87 and a front transparent guide 88.

The developing station 40 is of the magnetic-brush type and comprises a container 97 for containing a developing powder comprising `a mixture of a toner powder and a magnetic carrier powder.

A rotor 98 of magnetic material is supported for rotation in the container 97, said rotor having the shape of a cylinder and bearing on its surface a plurality of grooves or one or more helical ridges and being permanently geared to the shaft of the motor M.

A permanent magnet unit 99 is arranged to produce a magnetic field having horizontal lines of force directed from magnets 99 to rotor 98, thus traversing over its entire width the copy sheet fed between said rotor and a non-magnetic guide 135. Therefore the projections of rotor 98 pick-up from container 97 magnetic carrier powder particles having toner powder particles attached thereto by triboelectric effect, whereby said toner powder particles adhere to the areas of the sheet which upon exposure have not been discharged, while the carrier powder falls thereafter into the container. A pair of -screws 136, permanently geared to the shaft of the motor M is provided for mixing and uniformly distributing the developing powder in the container 97.

The container 97 .and the other parts of the developing station are mounted on two legs 138, having a fork-shaped end `rotatably supported by fixed studs 139, whereby the developing station may be either partially or completely extracted from the machine for inspection and cleaning and replenishment with fresh developing powder.

The fixing station 41 comprises a lamp F cooperating with a reflector 140 to fuse the powder adhering to the photoconductive sheet. The illuminating lamp L and the fusing lamp F are surrounded by ducts conveying cooling air moved by a fan not shown in FIG. l.

FIG. 2 shows a mechanism located in the gear box 12 at the right-hand side of the machine for controlling the three clutches 60, 52 and 82 by means of a single electromagnet E.

For closing the single- revolution clutches 60 and 82, that is for engaging their motor parts with their driven parts, it is necessary to counterclockwise rotate the lever 101 and 102 respectively on fixed axis 103 and 104 respectively against the action of a spring 105 and 106 respectively, so as to momentarily disengage the projection 130 and 131 respectively from said levers.

The continuous clutch 52, which is permanently closed when a lever 107 pivoted on a fixed axis 108 is in the position shown in FIG. 2, may be opened by clockwise rotating the lever 107.

The movable core 108 of the electromagnet E when lowered causes lever 109 to turn on a fixed axis 110, so as to raise a pin 111 fixed to an arm 113 and slidably engaged in a slit 112 of said lever 109.

A crank 114 by clockwise rotating on a fixed axis 121 causes a plate 115 to rotate coutnerclockwise on a fixed axis 108, whereby the lever 116 is caused to clockwise rotate on a fixed axis 117. Therefore said arm 113, which is pivoted to the lever 116, is moved right from the position shown in FIG. 2 until the pin 111 reaches the righthand end of the slit 112.

The crank 114 is driven by the aforementioned rollsheet selecting know, in such a way that the position of the crank 114 indicated in FIG. 2 corresponds to the shee position of said knob, whereas the position of said crank 114 rotated clockwise 45 corresponds to the roll position of said knob. In the sheet position the crank 114 by means of a pin 12S keeps lever 107 out of engagement with clutch 52, so as to maintain said clutch positively closed, whereas in the roll position the lever 107 can freely rotate and is normally held by a spring Cil 129 in such a position as to maintain clutch 52 opened.

The lever 107 is connected to lever 109 by a bar 125 having a slit 126 wherein a pin 127 fixed to the lever 109 may slide. Therefore when crank 114 is in the roll position, control of the clutch 52 is deferred to the electromagnet E.

An oscillating arm 118 pivoted on crank 113 and urged by a spring 119 against an abutment 120 fixed to said crank is able to rotate levers 101 and 102 which control the clutches 60 and 82 respectively. More particularly, when the crank 114 is in the sheet position shown in FIG. 2, the electromagnet E when energized causes the lever 109 to rotate counterclockwise from the inoperative position shown in FIG. 2 to a working position, whereby arm 118 is pushed against the pin 123 of the lever 101 to cause lever 101 to rotate so as to close clutch 60. Furthermore the arm 118 continuing its movement disengages lever 101, which therefore becomes free to resume its initial position under the action of spring and thus to engage the projection 130 of the clutch. Therefore it is apparent that in this position of the preselection crank 114 the clutch 60 is closed for one revolution at the moment when electromagnet E begins to be energized, while clutch 82 remains continuously open.

Moreover, when the preselection crank 114 is in this position, the energization of the electromagnet E does not affect the position of the lever 107, because pin 127 moves in the slit 126 without raising the bar 125, whereby the continuous clutch 52 remains closed. On the contrary, when crank 114 is in the roll position, wherein the arm 113 is displaced in the left-hand position, the arm 118 is removed from lever 101 and is driven to contact at its right-hand edge the pin 122 of the lever 102. Furthermore the bar 125 is urged downward by spring 129, whereby the upper end of the slit 126 contacts pin 127. Under these conditions the energization of the electromagnet E does not affect the position of levers 101 and 102; however it presets arm 118 for closing the clutch 82, as the lower end of the arm 118 is driven into engagement with pin 122. Moreover the bar 125 causes lever 107 to rotate clockwise, whereby clutch 52 is closed. Thereafter, when the electromagnet E is deenergized, lever 109 is caused to rotate clockwise by spring 124, whereby the arm 118 is pushed down and thus causes lever 102 to rotate so as to close the clutch 82. Also in this case the arm 11S continuing its travel disengages pin 122 of the lever 102, whereby lever 102 becomes free to resume its inoperative position under the action of spring 106 so as to engage the projection 131 of the clutch 82. There'fore it is apparent that when the preselection crank 114 is in this second position, at the moment when the electromagnet E begins to be energized the arm 118 is preset for closing clutch 82, which is effectively closed only at the moment when the electromagnet E is deenergized. Moreover clutch 52 remains closed only as long as the electromagnet E remains energized, whereas clutch 60 is never closed.

An arm 132 pivoted to the plate 115 has fixed at its lefthand end an electrical switch MSC controlled by a lever 133.

Two feelers 151 and 152 are located on the document illumination path (FIG. 1). Each feeler comprises a lever having one end located on the document path, so as to be counterclockwise rotated when document travels thereunder, this lever being connected to an arm 153, 154 respectively, which moves the switch controlling lever 133.

One end of the lever 133 engages either one end of the arm 153, as shown in FIG. 2, or one end of the arm 154, according as to whether arm 132 is in its left-hand or right-hand position, that is whether crank 114 is in the sheet or roll position. Therefore it is apparent that switch MSC may be selectively controlled either by feeler 151 or by feeler 152.

The electrical circuit of the machine comprises (FIG. 3) the document illuminating lamp L, which can be connected between a pair of lines 201 and 202 through the Contact R3 of a relay R; the fusing lamp F, the motor M and an electrostatic charging circuit CE which can be connected between said lines through another contact R4 of said relay; the electromagnet E which can be connected between said lines through switch MSC controlled either by document sensing feeler 151 or by document sensing feeler 152; and the fan V permanently connected between said lines.

The relay R is provided with a contact R1 for controlling a locking circuit for the relay and with a contact R2 for controlling a timer T, which in turn upon stopping after a predetermined time interval causes a contact T1 to be opened for breaking said locking circuit.

The switch MSP controlled by the oscillatable upper table 1 of the machine is able to energize the locking circuit of the relay R.

The lines 201 and 202 may be connected to the power network through a general switch I. All the contacts are shown in FIG. 3 in their steady state position.

The charging circuit comprises a transformer 203 feeding a rectifying unit comprising diodes 204, 205 and condensers 206, 207 for maintaining wires 86 and 85 at continuous high positive, respectively negative potential.

The operation of the machine will now be briefly described with reference to the time diagram of FIG. 5, wherein thick lines indicate the time intervals during which the switch MSP, the relay R, the lamps L and F, the -motor M, the charging circuit CE and the electromagnet E are energized and the clutches 52, 60 and 82 are closed.

It is first assumed (FIG. 5a) that the preselection knob has been preset in the roll position, whereby the pair of driving rollers 73, 74 is positioned to engage the motor roller `49, the switch MSC is displaced in its right-hand position for being controlled by feeler 152 and the lever 107 (FIG. 2) is positioned by spring 129 to maintain the continuous clutch 52 closed.

Upon closing the general switch I, fan V starts.

The document to be copied is then deposited on the upper table 1 to contact the aligning margin guide 3 and thereafter it is pushed into the entrance opening 2. The pressure concurrently exerted by the hand on the oscillatable upper table 1 causes switch MSP to be momentarily operated. Therefore the relay R is energized so as to close the locking contact R1 and the contacts R2, R3 and R4, whereby the document illuminating lamp L, the fusing lamp F, the charging circuit CE and the motor yM are energized. This causes the driving rollers 5, 9, 10, 89, 91, 93, the motor parts of the clutches 60, 52 and 82 and the rotating parts of the developing station 40 to lbe continuously rotated.

Therefore the document upon being pushed into engagement with the pair of rollers 4 and 5 is driven along the illumination path and, upon reaching the feeler 152, operates switch MSC to energize the electromagnet E, which thereafter remains energized as long as the document itself contacts said feeler.

The electromagnet E by rotating the lever 109 (FIG 2) raises the bar 125 which rotates clockwise the lever 107 against the action of spring 129 so as to close the clutch 52. Therefore the roller 49 begins to rotate, thus causing the rollers 73 and 74 to rotate for feeding photosensitive paper 42 from paper roll 44 toward the charging station 39 and thence toward the exposure station 35, which is reached by the leading edge of the copy sheet just when the leading edge of the document to be copied reaches the illumination station 29.

When the trailing edge of the document reaches the feeler 152, switch MSC returns to the inoperative position shown in FIG. 3.

Therefore the electromagnet E is deenergized, whereby lever 109 (FIG. 2) is released for clockwise rotation to the inoperative position under the action of the spring 124. Thus arm 118, whose lower end engages pin 122, is pushed downward to cause lever 102 to rotate so as` to close the clutch 82 for a single revolution. This clutch actuates the cutting blade 79, whereby a sheet having a length exactly corresponding to the document length is cut from the paper roll 44. Furthermore, as the electromagnet E is deenergized, lever 107 (FIG. 2) is allowed to rotate counterclockwise under the action of spring 129 to open the continuous clutch 52, whereby rollers 49, 73 and 74 stop. In the meantime, rotation of rollers 89, 91 and 93 is continued for driving the copy sheet, while rotation of rollers 5, 9 and 10 is continued either to drive the document a second time along the illumination Ipath, should the decctor 30 have been preset for multiple copy operation, or to `deliver the document onto the document receiving plate 31, should the dellector 30 have been preset for single copy operation.

More particularly, the switch MSC upon resuming its inoperative position after passage of the trailing edge of the document under the feeder 152 starts the timer T, which after a predetermined time interval opens the contact T1 to break the locking circuit of the relay R. Upon deenergization of the relay R, the lamps L and F, the charging circuit CE are deenergized. Motor M is also deenergized, whereby all paper feeding rollers stop. The duration of said time interval of the timer T is predetermined to such a value as to allow the copy sheet to complete its path through the developing station 40 and the fixing station 41. Thereafter the copy sheet is delivered onto the upper table 1.

It is now assumer (FIG. 5b) that the preselection knob has been preset in the sheet position, whereby the pair of rollers 73, 74 is spaced from motor roller 49, the continuous clutch 52 is permanently closed because lever 107 is maintained out of engagement with said clutch by the pin 128, as shown in FIG. 2, and the switch MSC is displaced to assume its lefthand position so as to be controlled by the feeler 151.

After closing the general switch I, the operator inserts the document into the machine and by pushing down the upper table 1 operates the switch :MSP to energize the relay R, whereby the lamps L and F, the charging unit CE and the motor M are energized. Therefore rollers 5, 9, 10, 89, 91 and 93 begin to rotate as in the preceding case. Moreover in the present case also the -roller 49 is caused to rotate as the clutch 52 is continuously closed.

When the leading edge of the document reaches feeler 152, the electromagnet E is energized, so as to cause lever 109 (FIG. 2) to rotate, whereby the arm 118 is pushed upward for rocking the lever 101 to close the clutch 60. Clutch 60 makes one revolution, during which the sheet feeding roller 53 is driven through a single and complete stroke to feed the upper sheet of the ream 46 into engagement withl the pair of rollers 49 and 50.

The feeler 151, which is operative in the present sheet position of the preselection knob, is located on the document path to precede the feeler 152, which is operative in the above considered roll position of said preselection knob, by a distance corresponding to the time spent 'by the leading edge of the upper sheet of the ream 46 to reach the cutting blade 79. Therefore the leading edge of said sheet raches the cutting blade 79 just when the leading edge of the document reacties the feeler 152 which is now inoperative, that is at the moment when the leading edge of the paper fed from roll 44 would have started moving right from the cutting blade 79. It is thus apparent that using a pair of feelers allows proper synchronism between the movements of document and copy sheet to be kmaintained in every case.

The copy sheet engages first the pair of rollers 73 and 74 and then the pairs of rollers 89 and 90, 91 and 92, 93

station 39, the exposure station 35, the developing station 40 and the fixing station 41 and thereafter deliver it on the upper table 1.

Also in this case, when the trailing edge of the document reaches the feeler 151, the switch MSC upon resuming its inoperative position causes the electromagnet E to be deenergized, and the timer T to be started. Timer T acts as previously described on the locking circuit of the relay R to maintain lamps L and F, charging unit CE and motor M energized during a predetermined time interval after deenergization of the electromagnet E.

As said deenergization in this case does not aiect the clutches 60, 52 and 82 of FIG. 2, the rotation of rollers 5, 9, 10, 89, 91, 93 and 49 is not discontinued until the end of said time intervaL'whereby the movement of the copy sheet may be completed as required.

From the foregoing description it will be understood that many changes may be made in the above construction, and different embodiments of the invention could lbe made without departing from the limits thereof.

It is, therefore, intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative, and not in a limiting sense.

What I claim is:

1. Electrophotographic copying machine comprising:

(a) an illumination path for a document to be copied;

(b) an upper table for sustaining said document for insertion along an aligning margin guide into said illumination path, said table being slightly depressible;

(c) means for feeding said inserted document along said illumination path;

(d) an exposure path;

(e) means responsive to insertion of said document for feeding a copy sheet along said exposure path;

(f) electrostatic charging means for said copy sheet;

(g) means for illuminating said fed document to project an image thereof onto said fed copy sheet;

(h) image developing means;

(i) image xing means;

(j) an electrical switch responsive to depression of said table for energizing said means;

(k) and a feeler in said illumination path responsive to passage of the trailing edge of said document for deenergizing said means.

References Cited UNITED STATES PATENTS 2,579,961 12/1951 Popma. 3,282,177 10/ 1966 Stanton JOHN M. HORAN, Primary Examiner

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