GB1564155A

GB1564155A - Sheet feeding apparatus

Info

Publication number: GB1564155A
Application number: GB50079/76A
Authority: GB
Original assignee: De la Rue Crosfield Ltd
Current assignee: De la Rue Crosfield Ltd
Priority date: 1978-02-21
Filing date: 1978-02-21
Publication date: 1980-04-02

Description

(54) SHEET FEEDING APPARATUS (71) We, DE LA RUE CROSFIELD LIMITED, a British Company of De La Rue House, 3-5 Burlington Gardens, Lon dqn, W1A 1DL (formerly of 84/86 Regent Street, London, W1A 1DL) do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to sheet feeding apparatus of the type adapted to remove flexible sheets from a stack of sheets by means of a primary frictional feed means acting on the face of an exposed sheet and to feed them one at a time in a direction substantially parallel to the said face into a flow-line. Such apparatus is hereinafter referred to as "apparatus of the type described".

Whilst the invention is especially applicable to apparatus for handling documentsize sheets, for example, banknotes, it may also be used for feeding other types of sheets to a printing or processing machine.

When the feeding apparatus is used as a part of a banknote counting machine it is extremely important that only single sheets are fed into the flow-line and also that adequate gaps are formed between adjacent sheets to enable sheet sensing means to recognise, and hence to count the individual sheets. In such machines, special problems are encountered when it is desired to feed used banknotes that are not in perfect condition, for example, the structure of such banknotes may have weakened or degraded and, furthermore, they may include worn or torn leading edges.

It thus follows that when handling sheets of indeterminable condition the interleaf friction between the adjacent sheets in a stack may vary considerably and, therefore, it is usual in feeding apparatus of the type described to provide some form of holdback or stripper means to prevent, or at least substantially to prevent, a superposed sheet from being fed inadvertently along the flow-line by the frictional feeding - means.

Effective operation of such a stripper means necessarily entails mechanical engagement with the superposed sheets and in certain known constructions it has been found that it is possible to damage the leading edges of such sheets. Apart from the undesirable damage caused to the superposed sheets in repelling them from the feeding nip, experience has shown that the sheets so damaged can create a flow impedance when they are presented to the said nip with the result that the overall throughput of the feeder is impaired and, in extreme cases, is totally arrested by the creation of an obstruction.

According to this invention sheet feeding apparatus of the type described comprises a feeding nip disposed downstream of said primary feed means and defined by a driven secondary friction feed means for propelling a sheet further along the flow-line and in association with a driven stripper means for repelling a superposed sheet or sheets, a sheet seizing means disposed downstream of said feeding nip for seizing the leading end of a sheet whilst it is in engagement with the primary feed means and a drive control means for controlling drive to said primary feed and stripper means in such a manner that drive thereto is disconnected after the leading end of a sheet has been seized by said sheet seizing means and is restored after the trailing end of that sheet has passed downstream thereof.

Preferably, the drive to the primary feed means and the stripper means is controlled by a device operable by the passage of a sheet, said device being disposed downstream of the seizing means. The said device may comprise an electrical switch having an operating lever adapted to obstruct the flow-line and arrange to connect or discon nect the drive through the medium of an electromagnetic clutch, upon the passage of each sheet. Alternatively, the said device may be of the optical type arranged to actuate an electromagnetic clutch through the medium of a relay or an electronic amplification means. In a first embodiment it may comprise a light source positioned on one side of the flow-line and an associated light-responsive detector on the other side, so as to respond to the passage of a sheet. In a second embodiment, the light source and the associated light-responsive detector are disposed remotely from the flow-line and the attenuation of light therebetween is controlled by a mechanical device which in turn is responsive to the passage of sheets.

In a convenient construction a fixed-axis reference roller is provided on one side of the flow-line and an associated movable-axis reference roller on the other side. The latter roller is biased towards the former roller and is carried on a pivotal lever assembly which serves to effect the said attenuation of light.

Alternatively, the said device may comprise a proximity detector arranged to respond, either directly, or indirectly through an intermediary mechanical means, to the passage of sheets thereby to actuate the clutch through suitable circuitry.

Alternatively, the drive may be connected or disconnected by a mechanical clutch having an actuating element disposed downstream of the seizing means and arranged to obstruct the flow-line in a first position and to move therefrom upon the passage of a sheet thereby to disconnect the drive.

Preferably, the primary feed means and the reverse-direction stripper means comprise rollers having frictional peripheries, of for example, polyurethane.

Preferably, the secondary friction feed means comprises a roller driven from the main drive mechanism of the apparatus and provided with a frictional periphery having a lower durometer hardness factor than that of the stripper roller. In a particularly convenient construction the said roller comprises a hub component of non-yieldable material. said hub being circumferentially grooved to receive frictional peripheral components. for example, rings of plastics material of circular cross-section.

Preferably, the primary feed roller and the stripper roller are rotationally connected together, for example, by means of a pulley and belt system or alternatively, by means of a gear train.

Preferably, the primary feed roller is provided with means to create an impedance to forward rotation and also a means to prevent reverse-direction rotation. i.e. in a direction opposite to that of the flow-line.

Conveniently said means comprises a pawl and ratchet wheel, the impedance being created by the deflection of the pawl by the teeth of the ratchet wheel, and the prevention of rotation being effected by the abutment faces of the said teeth.

A non-limiting example of the invention will now be described with reference to the drawings accompanying the Provisional Specification of which, Figure 1 is a diagrammatic side elevation showing the stack and essential roller components of a feeding mechanism; Figure 2 is an end view as indicated by symbols II-II of Figure 1; Figure 3 is an enlarged partly sectioned fragmentary view as indicated by symbols III-III of Figure 1, and Figure 4 is a perspective view of the principal components of the mechanism.

It will be appreciated that the drawings are mainly diagrammatic and that for reasons of clarity all shaft bearings, mainframes and other structural components which are not critical to the understanding of the invention have been omitted.

Stack Assembly Referring first to Figure 1, a stack of banknotes S is supported within a detachable storage cassette C of a rectangular box-like construction comprising a front plate 1, a rear plate 2, a pair of side plates (one of which is indicated by symbol 3), and a bottom plate 4. The frontal portion of the bottom plate and the lower extremity of the front plate are cut-away as shown to permit entry of a part of the feeding mechanism and the leftward exit of banknotes, respectively. A pressure plate member, generally indicated by symbol 5, is provided to bear upon the top of the stack S, thereby to bias the lowermost banknote against the feeding mechanism. The pressure member comprises two horizontal plate portions 6 and 7 joined together by means of an intermediate plate portion 8 disposed at an angle to the bottom plate 4, and is biased in a downward direction by spring means indicated by the arrow P. Suitable guide means (not shown) are provided in the sides of the cassette to maintain the angular position of the pressure member throughout its movement, and it will thus be seen that a maximum force is exerted by the biasing means through a line disposed opposite the feeding mechanism which is described below. It thus follows that interleaf pressure between the banknotes at the trailing end of the stack is substantially reduced and, accordingly, the frictional impedance incurred in withdrawing the lowermost note is minimised.

To assist in the control of the stack when the contents thereof near depletion and to ensure that the ultimate banknote is fed into the flowline, a pair of strips of fricional material are attached to the underside of the pressure plate member in the position indicated by the hatched lines 9. The strips, which are of 1 mm, polyurethane having a hardness of approximately 60 DURO METER on the "A" scale, are 6 mm. wide and extend rearwardly from the leading end of the pressure plate member for approximately 100 mm. It is essential that the strips do not make direct contact with the primary feed means upon depletion of the stack and accordingly they are disposed outwardly of the primary feed means (when viewed in plan), to provide a clearance of approximately 2 mm. The purpose of the strips is to create friction between the top of the stack and the underside of the pressure member thereby to reduce the tendency to rearward movement of the stack brought about by the angled plate 8.

The feeding of the ultimate banknote in the stack is not impeded by the strips because of the relative frictional characteristics of the respective contacting surfaces.

Suitable releasable locking means and location means (not shown) are provided to secure the cassette within the apparatus in a predetermined position.

Feed Mechanism The feeding mechanism comprises a pair of primary frictional feed rollers 10, axially spaced upon a shaft 11, the ends of which are journalled in the mainframes of the apparatus. Each roller comprises a metallic hub portion and a polyurethane peripheral portion having a hardness of 55 D\JRO- METER on the "A" scale. Transverse notches are formed in the periphery of the rollers to assist effective engagement with the underface of the stack and also to provide witness marks thereby to enable the degree of wear incurred by the rollers to be visibly assessed. The notches, which are approximately 2 mm x 2 mm, are indicated by symbol 12 (see especially Figure 4).

The primary feed rollers 10 are in continuous contact with the face of the stack S, and accordingly. when they are rotated in an anti-clockwise direction by the means desribed below, the lowermost banknote will be fed across the face of the stack into a feeding nip and thence along a flow-line, indicated by symbol F.

The feeding nip comprises an axially spaced pair of feed rollers 13 disposed tangentially to, and below the flow-line, in association with an aligned pair of reversedirection or stripper rollers 15 disposed above the flow-line. The feed rollers 13 are fixedly mounted upon a driven shaft 14 and the stripper rollers 15 are mounted upon a driven shaft 16. A more detailed description of these rollers is given below in conjunction with Figure 3. Also associated with the feeding nip are two pairs of stationary guide fingers 17, each pair being arranged to straddle a stripper roller 15. The fingers, which depend towards the flow-line, -are integrally formed with a common transverse support plate 18 which is fixedly mounted to the framework of the apparatus adjacent the front plate 1 of the cassette. From Figure 1, it will be seen that each finger terminates at a substantially horizontal guide surface which merges with an angled guide surface in a rearward direction. The underside of the fingers thereby guide the leading edges of the banknotes into the nip of the rollers 13 and 15, and additionally, serve to protect the said edges from damage by the stripper rollers 15. Height adjustment means (not shown) are provided for both the stripper rollers 15 and the fingers 17, thereby to enable the apparatus to be pre-set to obtain optimum performance for a particular type of banknote.

Downstream of the feeding nip there is provided a seizing nip which is diagrammatically shown as opposed pairs of driven rollers (see symbol 19). The exact configuration and location of the seizing nip is not critical to the invention but conveniently it is positioned in close proximity to the abovedescribed feeding nip.

The construction of the components comprising the feeding nip will now be described with reference to Figure 3 which shows one of the stripper rollers 15 and the upper part of an associated feed roller 13 in vertical cross-section. The roller 13 which has an overall diameter of 43 mm is machined for aluminium and includes three annular grooves, 20, 21 and 22 in its cylindrical surface. Grooves 20 and 22 are of rectangular cross-section and serve to accept toroidal rings 23 of a resilient frictional material having a DUROMETER hardness of 75 on the "A" scale. The rings thereby form a pair of spacially disposed driving surfaces to engage and forward a single banknote through the feeding nip. The central groove 21 is adapted to carry one end of an endless guide belt 24 which is also of circular cross-section. The other end of the guide belt is carried on an idler pulley 25see chain dotted outlines in Figures 1 and 4) which is carried on a stub shaft, not shown.

From Figure 4, it will be seen that two such belts and associated idler pulleys are provided. The belts are disposed below, and clear of. the flow-line and serve to prevent the leading ends of banknotes from deviating in a downward direction during feeding.

Returning to Figure 3, the stripper roller 15 comprises a metallic hub portion 26 which mounts a resilient tyre having a substantially spherical external surface 27. The tyre is of polyurethane and has a hardness of 90 DUROMETER on the "A" scale. The axis of shaft 16 which carries the roller 15 is adjusted to define a clearance for the passage of a single note between the external surface 27 of the stripper roller 15 and the rings 23 of the drive roller 13. It will be appreciated that the spherical surface of the stripper roller will tend to form a mild longitudinal corrugation in the banknote and also to deter entry of a superposed banknote through the nip. The fingers 17 are also included in Figure 3 to illustrate at dimension X, a suitable height adjustment relative to the upper extremity of the feed roller 13.

Drive and Control Mechanism The shaft 14 carrying the feed rollers 13 constitutes the main drive shaft for the feed mechanism and is driven at 600 r.p.m. by means of a geared electric motor (not shown) to provide a flow-line velocity of 1350 mm/second. Thus, when feeding banknotes, having a longitudinal length of 160 mm, at a rate of five per second, the gaps formed between adjacent banknotes are adequate for the reliable operation of a counting device.

The shaft 11 upon which is mounted the primary feed rollers 10 is driven from shaft 14 via a gear train comprising a pinion 28 fast with the shaft 14, an idler gear 29 and a further gear 30 integral with the input component of an electromagnetic clutch, generally indicated by symbol 31. This component rotates freely on shaft 11, and upon energisation of an electromagnet via the conductors 32, transmits drive to the output component 33 of the clutch, which is fixedly mounted to the shaft 11. The gear train provides an effective reduction ratio of 1:3 and, in conjunction wih primary feed rollers of 25 mm diameter, creates a peripheral velocity of approximately 260 mm/second. It will thus be seen that a banknote fed forward by the primary feed roller is accelerated by the feed rollers by a theoretical factor of approximately 5:1.

However, in practice, slippage reduces this factor slightly and positive traction is not attained until the leading edge of the banknote is seized by the roller nip 19.

The shaft 16, mounting the reversedirection rollers 15, is driven from shaft 11 by means of grooved pulleys 34 and 35 in conjunction with a driving belt 36. The rollers are 20 mm in diameter and the pulleys 34 and 35 are arranged to effect a speed reduction thereby to provide the stripper rollers with an effective peripheral velocity of approximately 160 mm/second in a direction opposite to that of the flow-line.

To prevent opposite rotation of the stripper rollers 15 during a part of the feeding cycle a ratchet wheel 37 is fixedly mounted to the shaft 16. A spring-loaded pawl 38.

attached to the framework of the apparatus.

by means not shown, is arranged to engage with the teeth of the ratchet wheel and to prevent clockwise rotation of the shaft 16.

When the shaft 16 is rotated in an anticlockwise direction (i.e. when driven by the belt 36), the pawl rides over the teeth of the ratchet wheel and provides an impedance to rotation.

Energisation of the electromagnetic clutch 31 is controlled by means of a "normally closed" micro-switch MS disposed downstream of the nips of the seizing rollers 19. The switch is connected in series with the windings of the clutch and a current source V2, and is provided with an actuating lever 39 obstructing the flow4ine (see especially Figure 1). It will be appreciated that the feeding rate of, and the length of the gaps between the banknotes, will be dependent upon the position of the switch MS.

Operation of the Apparatus (see Figure 1) A loaded cassette containing a stack of banknotes S is located in the apparatus so that the lowermost banknote N1 is biased against the primary feed rollers 10. Upon connecting a current source V1 to the driving motor the feed rollers 13 and the seizing rollers 19 are rotated. Feeding of banknotes is effected by connecting V2 to a current source; this energises the clutch 31 which drives the primary feed rollers 10 and the stripper rollers 15, thereby to feed forward (viz in a leftward direction) the lowermost banknote N1. The leading end of the banknote is guided below the fingers 17 and is fed into the nip of the feed rollers 13 and the stripper rollers 15. The former rollers convey the banknotes N1 through the nip and the latter rollers holdback superposed banknotes inadvertently fed forward with N1.

The leading end of N1 enters the nip of the seizing rollers 19 where it is positively gripped and propelled along the flow-line F.

When the said leading end strikes the switch-actuating lever 39 it opens the contacts of the switch and thereby de-energises the clutch. Thereafter, the banknote N1 is pulled across the primary feed rollers 10 and the stripper rollers 15. Initially, the frictional contact between the moving banknote N1 and the primary feed rollers cause the latter to rotate against the impedance created by the pawl and ratchet (38 and 37 in Figures 2 and 4). However, when the trailing end of N1 passes beyond the primary feed rollers 10 it ceases to rotate and the pawl and ratchet prevents the banknote N1 from rotating the stripper rollers 15 in clockwise direction and accordingly there is no possi ability of the primary feed rollers moving the following banknote. Finally. when the said trailing end passes beyond the switchactuating lever 39 the clutch is re-energised thereby initiating a further feeding cycle.

It will thus be appreciated that the stripper rollers engage the superposed banknotes for as little time as possible between feeding cycles, and accordingly, wear of the said rollers is minimised and damage to the edges of the banknotes is substantially reduced.

It should be noted that whilst a mechanically operated electrical switch is used in the above described embodiment to control the clutch, other suitable switching means may alternatively be employed. For example, an optical type device comprising a photoelectric sensor may be disposed on one side of the flow-line with an associated light source on the other side; the output from the sensor being arranged to energise the clutch, when no banknote is present, by relay or thyristor controlled switching means, in a known manner.

Alternatively, the above photoelectric type device may be used in conjunction with a mechanically operated light-beam interrupter to actuate the switching means upon the passage of banknotes. This may comprise a fixed-axis reference roller and an associated movable nip-sensing roller mounted on an amplified lever system, which in turn controls light passing between the light source and the photoelectric sensor. In operation, the presence of a banknote in the nip rotates the said lever system thereby to interrupt the passage of light and to de-energise the clutch in the manner described above.

Alternatively, the fixed axis reference and the associated movable nip-sensing roller, as used in the last mentioned example, may be arranged to control the clutch via the intermediary of a proximity detector instead of by optical means. In this case, the said detector is fixedly mounted in spacial relationship with respect to the periphery of the sensing roller in such a manner that the existence of a banknote within the nip reduces the spacing between the sensing roller and the detector thereby to generate an output signal which is processed electronically to de-energise the clutch. If desired an electronic time-delay means mav be included in the circuitrv of the abovementioned alternative examples, to delay re-establishment of power to the clutch after the passage of each banknote thereby to increase the size of the gaps formed between adjacent banknotes fed along the flow-line.

In a still further embodiment the control of power to the primary and reversedirection rollers may be effected wholly by mechanical means. Such an arrangement may comprise a movable component adapted to obstruct the flow-line and which, upon the passage of a banknote, is arranged to trip the controlling element of a mechanical-type clutch, for example, a clutch of the wrapped-spring type.

It will further be appreciated that whilst the above mechanism describes a feeder adapted to feed sheets from the bottom of a horizontal stack, it may be equally be applicable to feeders and stacks disposed in other orientations.

WHAT WE CLAIM IS: 1. Sheet feeding apparatus of the type described comprising a feeding nip disposed downstream of said primary feed means and defined by a driven secondary friction feed means for propelling a sheet further along the flow-line and in association with a driven stripper means for repelling a superposed sheet or sheets, a sheet seizing means disposed downstream of said feeding nip for seizing the leading end of a sheet whilst it is in engagement with the primary feed means and a drive control means for controlling drive to said primary feed and stripper means in such a manner that drive thereto is disconnected after the leading end of a sheet has been seized by said sheet seizing means and is restored after the trailing end of that sheet has passed downstream thereof.

2. Sheet feeding apparatus as claimed in Claim 1 wherein said drive control means comprises an electrical circuit incorporating an electromagnetic clutch adapted to connect or disconnect drive to the primary feed and stripper means, and a switch means responsive to the passage of sheets along the flow-line to control the clutch.

3. Sheet feeding apparatus as claimed in Claim 2 in which said switch means comprises a normally-closed electrical switch having an operating lever adapted to obstruct the flow-line but upon the passage of a sheet to move therefrom thereby to open said switch.

4. Sheet feeding apparatus as claimed in Claim 2 in which said switch means comprises a light source positioned on one side of the flow-line. a light-responsive detector disposed to receive light from said source on the other side of the flow-line, and means to amplify an output signal created by said detector to actuate said switch means.

5. Sheet feeding apparatus as claimed in Claim 2 in which said switch means comprises a fixed-axis reference roller disposed on one side of the flow-line and an associated movable sensing roller biased towards said reference roller disposed on the other side of the flow-line. and a detector means responsive to the movement of the sensing roller away from the reference roller upon the passage of sheets to control the clutch.

6. Sheet feeding apparatus as claimed in Claim 5 in which said detector means comprises a photo-electric device together with an associated light source, and the said sensing roller is mounted on a pivotal lever

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. thereby initiating a further feeding cycle. It will thus be appreciated that the stripper rollers engage the superposed banknotes for as little time as possible between feeding cycles, and accordingly, wear of the said rollers is minimised and damage to the edges of the banknotes is substantially reduced. It should be noted that whilst a mechanically operated electrical switch is used in the above described embodiment to control the clutch, other suitable switching means may alternatively be employed. For example, an optical type device comprising a photoelectric sensor may be disposed on one side of the flow-line with an associated light source on the other side; the output from the sensor being arranged to energise the clutch, when no banknote is present, by relay or thyristor controlled switching means, in a known manner. Alternatively, the above photoelectric type device may be used in conjunction with a mechanically operated light-beam interrupter to actuate the switching means upon the passage of banknotes. This may comprise a fixed-axis reference roller and an associated movable nip-sensing roller mounted on an amplified lever system, which in turn controls light passing between the light source and the photoelectric sensor. In operation, the presence of a banknote in the nip rotates the said lever system thereby to interrupt the passage of light and to de-energise the clutch in the manner described above. Alternatively, the fixed axis reference and the associated movable nip-sensing roller, as used in the last mentioned example, may be arranged to control the clutch via the intermediary of a proximity detector instead of by optical means. In this case, the said detector is fixedly mounted in spacial relationship with respect to the periphery of the sensing roller in such a manner that the existence of a banknote within the nip reduces the spacing between the sensing roller and the detector thereby to generate an output signal which is processed electronically to de-energise the clutch. If desired an electronic time-delay means mav be included in the circuitrv of the abovementioned alternative examples, to delay re-establishment of power to the clutch after the passage of each banknote thereby to increase the size of the gaps formed between adjacent banknotes fed along the flow-line. In a still further embodiment the control of power to the primary and reversedirection rollers may be effected wholly by mechanical means. Such an arrangement may comprise a movable component adapted to obstruct the flow-line and which, upon the passage of a banknote, is arranged to trip the controlling element of a mechanical-type clutch, for example, a clutch of the wrapped-spring type. It will further be appreciated that whilst the above mechanism describes a feeder adapted to feed sheets from the bottom of a horizontal stack, it may be equally be applicable to feeders and stacks disposed in other orientations. WHAT WE CLAIM IS:

1. Sheet feeding apparatus of the type described comprising a feeding nip disposed downstream of said primary feed means and defined by a driven secondary friction feed means for propelling a sheet further along the flow-line and in association with a driven stripper means for repelling a superposed sheet or sheets, a sheet seizing means disposed downstream of said feeding nip for seizing the leading end of a sheet whilst it is in engagement with the primary feed means and a drive control means for controlling drive to said primary feed and stripper means in such a manner that drive thereto is disconnected after the leading end of a sheet has been seized by said sheet seizing means and is restored after the trailing end of that sheet has passed downstream thereof.

assembly the movement of which serves to control the amount of light passing between said light source and said photoelectric device.

7. Sheet Feeding apparatus as claimed in Claim 5 in which said detector means comprises a proximity detector disposed in spacial relationship to the periphery of the sensing roller in such a manner that the passage of a sheet along the flowline alters the spacing between the sensing roller and the detector and controls the clutch.

8. Sheet feeding apparatus as claimed in Claim 1 wherein said drive control means comprises a mechanical type clutch adapted to connect or disconnect drive by means of a mechanical strip element arranged to obstruct the flow-line but capable of moving therefrom by the passage of a sheet thereby to disconnect the drive.

9. Sheet feeding apparatus as claimed in any one of the preceding Claims wherein said primary feed means comprises at least one roller having a frictional periphery, fixedly mounted upon a driven shaft disposed transverselv to the flow-line.

10. Sheet feeding apparatus as claimed in any one of the preceding Claims in which the secondary friction feed means and said stripper means each comprise at least one roller having a frictional periphery fixedly mounted upon respective shafts disposed transversely to. and on the opposite sides of the flow-line.

11. Sheet feeding apparatus as claimed in Claim 10 wherein the frictional periphery of the friction feed roller comprises a material of lower hardness than that of the stripper roller.

12. Sheet feeding apparatus as claimed in either of Claims 10 and 11 wherein the cross-section of the stripper roller in an axial direction is convex.

13. Sheet feeding apparatus as claimed in any one of Claims 10 to 12 wherein the secondary friction feed roller comprises a hub portion of rigid material and said frictional periphery comprises a pair of axially spaced tvres.

14. Sheet feeding apparatus as claimed in Claim 13 wherein said tvres are of substantially circular cross-section and annular grooves are provided in said hub portion for the receipt of the tvres.

15. Sheet feeding apparatus as claimed in any one of the claims 10 to 14 wherein the shafts upon which are mounted the primary and stripper rollers are rotationally connected together bv belt drive means.

16. Sheet feeding apparatus as claimed in any one of Claims 10 to 15 wherein means are provided to prevent the stripper roller from rotating in the same direction as the flow-line at the feeding nip.

17. Sheet feeding apparatus as claimed in Claim 16 in which said means comprises a ratchet wheel fixedly mounted to the shaft bearing the stripper roller, and an associated spring-biased pawl adapted to engage said ratchet wheel.

18. Sheet feeding apparatus as claimed in Claim 17 wherein said means serves also to create a frictional resistance to rotation of the stripper roller in a direction opposite to the direction of the flow-line at the feeding nip.

19. Sheet feeding apparatus substantially as herein described with reference to the drawings accompanying the provisional specification.