GB2135284A

GB2135284A - Sheet feeder

Info

Publication number: GB2135284A
Application number: GB08402065A
Authority: GB
Inventors: Lionel Ernest Rawson; Toby Richard Crump
Original assignee: WOFENET Ltd
Current assignee: WOFENET Ltd
Priority date: 1983-01-27
Filing date: 1984-01-26
Publication date: 1984-08-30
Also published as: GB8402065D0

Abstract

A sheet feeder for feeding single sheets from a stack of sheets (16) comprising first drive means (19), a feed path (26, 27, 28) including at least one edge (31, 32), the first drive means being arranged to engage the top sheet of a stack of sheets and to drive said top sheet forwardly along the feed path to the edge, a second drive means (41) for pulling said sheet over said edge, and means to drive the second drive means so as, in use, to urge the sheet along the path at a higher speed than the first drive means. <IMAGE>

Description

SPECIFICATION Sheet feeder The present invention relate to a sheet feeder.

In particular the invention relates to a sheet feeder for feeding single sheets from a pile of sheets.

It is often necessary to feed single sheets from a pile of sheets, for example in photocopying machines, but in many circumstances the apparatus at present used is for feeding new sheets of material from a stack of sheets.

There are always problems if it is required to feed a single sheet at a time from a stack of sheets in that sometimes two sheets will be picked up from the top of the stack of sheets and fed through the apparatus. Various means have been devised to overcome this problem but they are generally applicable to stacks of new sheets of material with consistent qualities. The present invention provides an arrangement which will deal with new sheets of material or sheets of material of inconsistent physical qualities, such as sheets which are of different types of paper or of identicai paper which has already been used and is therefore liable to have creases or bent portions.

In its broadest aspect, therefore the invention provides apparatus for feeding single sheets from a stack of sheets, wherein the sheets may be sheets of new material or used or inconsistent sheets.

The invention provides a sheet feeder for feeding single sheets from a stack of sheets comprising first drive means, a feed path including an edge, the first drive means being arranged to engage the top sheet of a stack of sheets and to drive said top sheet forwardly along the feed path to the edge, a second drive means for pulling said sheet over said edge, and means to drive the second drive means so as, in use, to urge the sheet along the path at a higher speed than the first drive means.

The edge will tend to separate two sheets which have been fed together so that only the top sheet is fed through the apparatus.

This separation can be further improved by providing a lower surface of the path of a friction material.

Means is preferably provided to urge the second drive means and the path towards one another.

There may also be provided a second edge with a third driving means for pulling the sheet over the second edge and means to drive the third driving means so as, in use to urge the sheet along the path at a higher speed than the second drive means.

Means may be provided to urge the third drive means and the path towards one another.

The means to drive the second and/or third drive means is preferably adapted, in use, to urge the sheet along the path at a speed which is at least 10% faster than the preceding drive means. This will be sufficient in normal use to separate a top sheet and a second sheet which has been accidentally fed with it.

Means may be provided to urge the first drive means and the stack towards one another and in a particularly preferred arrangement, the drive means may be urged towards the stack.

In a convenient arrangement, each drive means comprises rollers or wheels, the peripheral surfaces of which may carry frictional material.

The or each edge over which the path passes may include pivoted members which are urged into engagement with the adjacent drive means. The pivoted members may be selectively movable to an alternative position in which they are spaced away from the adjacent drive means. In this alternative position sheets may easily be withdrawn from the feed path by, for example, the apparatus to which the feed apparatus is feeding sheets.

Means may be provided to move said pivoted members to their respective alternative positions, and said means may be controlled by a signal from the apparatus to which the sheet feeder, in use, feeds the sheets.

The angle of the edges, that is the angle between the path on each side of the edges, should generally be greater than about 10 and in a preferred arrangement are 30 or 40'.

The apparatus may include means to attach it to a photocopier, shredder or other apparatus.

Preferred embodiments of the invention will now be described by way of example only and with reference to the accompanying drawings in which: Figure 1 shows, in diagrammatic form, a side view of the sheet feeder apparatus with the side cover removed but the position of the side cover indicated, and Figure 2 shows a side view similar to Fig. 1 of an alternative sheet feeder.

Referring to Fig. 1, there is shown a photocopier 10 or similar apparatus to which the feeder apparatus 11 according to the invention is mounted by means of a releasable pin passing through respective holes 1 2 in the side plates 13, 14. The feeder apparatus 11 comprises the two above mentioned side plates 13, 14 between which the other components of the apparatus are mounted. Towards the front or input end of the apparatus 11 there is provided a stack of sheets of material 16. The stack 16 may be mounted on a plate 1 7 which either forms part of the feeder apparatus 11 or forms part of the photocopier apparatus 1 0.In either case, there is an aperture in the plate 1 7 (the plate 1 7 may be formed by fingers rather than being solid) and below the aperture forming part of the feeder apparatus 11 is a pivoted finger 1 8 which is urged so as to move upwardly through the aperture in the plate 1 7. If there are sheets of material in the stack 1 6 then the pivoted finger 1 8 will be held in a downward position but if there is no sheet material in the stack 1 6 the pivoted finger 1 8 can pivot to an upright position, shown in dotted lines in the drawing which can be used as an indication that there is no further material to be fed by the feeder apparatus 11.

Mounted to the feeder apparatus 11 above the stack 1 6 is a first drive means in the form of a roller 1 9. The roller may either be a single roller or may be formed from a plurality of coaxial wheels. The roller 1 9 is mounted to a pair of arms 21 and either under its own weight or with the assistance of springs the roller 1 9 is urged downwardly to engage the top of the stack 1 6. The roller 19 may have on its outer peripheral surface friction material and is conveniently formed of a rubber or frictional plastics material. The roller 1 9 is a driven roller and may be driven for example by a belt (not shown).

A feed path 55 for the sheets is provided by a so-called riffle board 23 on the top surface of which is provided frictional material such as rubber, cork or the like. The riffle board 23 defines three sections of path, a first section 26 sloping upwardly from the plate 17, a second section 27 which extends generally horizontally from the uppermost point of the first section 26, and a third section 28 which extends generally downwardly from the end of the second section 27. Thus edges 31, 32 are provided between the first and second sections 26, 27 and second and third sections 27, 28 respectively.The edges 31, 32 are quite sharp (the exact radius of curvature can be between 2 and 8, say 5mm). As is clear from the drawing part of the riffle board 23 on each side of the edge 31 is provided by a plurality of pivotal members 33 spaced across the riffle board 23 and pivoted about an axis 34 and urged by spring 36 so that the upper surfaces of the pivotal members 33 are urged towards the roller 41. A similar construction in the form of pivotal members 37, axis 38 and spring 39 provides part of the edge 32.

Just beyond the edge 31 the second section 27 of the riffle board 23 is engaged by a roller 41 rotatable about an axle 42, the roller 41 being in the form of a solid roller or wheels as with the roller 1 9 and having on its outer peripheral surface friction material which can be conveniently provided by manufacturing the roller 41 of rubber or plastics material.

The roller 41 forms a second drive means and is driven by means of a belt 43 which in turn is driven by a pulley 44 attached to a motor 46. The roller 41 is driven so that its peripheral speed is about 10% greater than the peripheral speed of drive of roller 1 9.

In passing it will also be noted that fingers 47 are provided which extend between the axis of roller 1 9 and the first section 26 of the riffle board 23.

There is provided beyond the edge 32 a third drive means in the form of a roller 48, similarly arranged to roller 41 to rotate about an axle 49 and driven by belt 43, the roller 48 also having a frictional peripheral surface and being in the form of a solid roller or separate wheels. The roller 48 is driven so that its peripheral speed is approximately 10% greater than the peripheral speed of roller 41.

It will be noted that the pivotal members 33 and 27 are urged into engagement with the rollers 41, 44 respectively by the springs 36 and 39.

The third section 28 of the riffle board 23 is arranged so as to direct sheets to the required input point 51 of the photocopier 10.

Adjacent the rear end, that is, the output end of the feeder apparatus 11, there is provided a pivoted finger 52 arranged generally similarly to the pivoted finger 1 8 to indicate when a sheet is passing over the third section 28 of the riffle board 23 and when it has been fed out of the feeder apparatus 11.

It would be understood, of course, that the pivoted fingers 18 and 52 may be attached to electrical switch means to provide control signals. There is also provided adjacent the pivoted finger 52 spring loaded fingers 53, arranged on either transverse side of the pivoted finger 52 to hold the sheet down whilst it passes the pivoted finger 52.

There is also provided a control system for controlling the feeder apparatus 11 which may be independent of or connected to operate together with the control system of the photocopier 10 8 or other machine to which the apparatus 11 is attached.

The apparatus thus far described may operate as follows. A stack of sheet material 1 6 is placed on the plate 1 7. The sheet material may be new identical sheets or may be used or irregular or sheets of different weights or thicknesses as desired. When the stack 1 6 is placed on the plate 1 7 the pivoted finger 1 8 is depressed away from the position shown in dotted lines.

The roller 1 9 engages the top surface of the stack 1 6 under its own weight, or, if desired, by a spring.

The apparatus is then set in motion. The motor 46 begins to drive which rotates, by means not shown, the roller 1 9. The roller 1 9 rotates in, in the figure, a clockwise direction so as to feed the top sheet 50 from the stack 1 6 to the left. The sheet is guided by the fingers 47 towards the surface of the first section 26 of the riffle board 23. The front edge of the sheet passes upwardly until it is engaged by the roller 41 and is fed through the nip between the rollers 41 and the upper surface of the pivotal member 33. It will be understood that the length of the sheet is sufficient that it extends between the roller 41 and 1 9 and since the peripheral speed of the roller 41 is slightly greater than that of roller 1 9 the sheet material is stretched.The sheet then passes along the second sction 27 of the riffle board 23 and is similarly gripped and driven through the nip between the roller 48 and pivotal member 37, which roller 48 has a peripheral speed about 10% greater than roller 41 so that again the sheet is stretched.

The sheet is then fed along the third section 28 of the riffle board 23, between the third section 28 and the spring fingers 53 to the input point 51 of the photocopier 10. It will be understood that it is not necessary, and indeed in some ways not desirable that the third section 28 of the riffle board 23 should have a friction surface but should be a polished metal or other low friction surface otallow easy feeding of the sheet from the roller 48 out of the apparatus. As the sheet passes the spring fingers 53 the pivoted finger 52 is depressed. This provides an output signal which may be used to count the number of sheets fed.

If by any chance, in addition to the top sheet, a second or even more sheets are fed with the top sheet, which is liable to occur with any stack 1 6 of sheet material but is particularly likely to occur where successive sheets of the sheet material are of different weight thickness or include creases, bends, folds or the like, the top sheet will go through t he process above described but the sheet below the top sheet will strike the frictional surface of the first section 26.Because of the angle at which it strikes that surface it will tend to separate the two sheets but if by any chance the two sheets pass through to the nip between the roller 41 and the second section 27 then the roller 41 will of course engage the top sheet and drive that forward but the lower sheet or sheets will be engaged by the friction surface and will not be engaged by the roller 41 and will therefore not be driven any further. This separation of the sheets is further enhanced by the presence of the relatively sharp edge 31.

If by any chance two sheets do pass through beyond the roller 41 then there is a second occasion to separate them by means of the roller 48 in a similar manner. It will be noticed that the angle between the first and second sections is approximately 30 whereas the angle between the second and third section 40 , that is a sharper edge which increases the likelihood of the two sheets being separated if, by any chance they are not separated by the first edge.

In practice the lower sheet will also be fed a certain distance by means of the first roller 1 9 when the first sheet has cleared the first roller 1 9 and by the second roller 41 when the first sheet has cleared the roller 41 but the photocopier is capable of dealing with one sheet at a time providing the leading edge of the two sheets are spaced apart from one another.

As above described the apparatus may be used in combination with a photocopier or other device. The apparatus is considered particularly suitable for use with a shredder in which used sheets of material of varying sizes, thickness and weights can be fed to a shredder which will handle only one or two sheets at a time.

The friction material on the top surface of the first and second sections of the riffle board may be formed of a soft rubber, either natural or artificial, or of a non-glazed cork.

Other materials may also be used. The difference in peripheral speed of the rollers provides for stretching of the sheets of material over the edges which tends to prevent sheets below a top sheet from feeding over the edges.

The arrangement of Fig. 2 is generally similar to that of Fig. 1, except that the drawing is taken from the opposite side to that of Fig. 1 so that the paper is fed from left to right across the drawing instead of from right to left. All parts are arranged similarly to that of Fig. 1, except as described in the following description. In this case, the pivotal members 33 and 37 are of different shape.

They do not extend to either edge 31 or 32, but simply consist of shaped fingers, the ends of which protrude through the relevant part of the riffle board 23 into engagement with the underside of the respective roller. The end finger surface is suitably shaped. The pivotal members 33, 37 are pivoted about respective axes 61, 62. The pivotal member 33, 37 are connected to respective links 63, 64 which in turn are connected to another link 65. The link 65 is connected to a plunger of a solenoid 66. Operation of the solenoid 66 withdraws the plunger and rotates, via the links 63, 64, 65 the pivotal members 33, 37 in the direction shown by arrows 67, 68.

The axes 61, 62 are provided by shafts and the pivotal members 33, 37 and links 63, 64 are mounted on the shafts 61, 62.

The operation of the apparatus of Fig. 2 is the same as in Fig. 1 and sheets fed from a stack 1 6 are separated in the same manner.

The difference is that the paper is fed to the position shown at 67, that is with the rear end at the point 68 and the front end at the point 69. From this position, the paper will be fed by drive means within the photocopier or other apparatus to which the sheet feeder is attached and to prevent unnecessary friction on the paper during this withdrawal the pivotal members 33, 37 are pivoted to the right as shown by the arrows 67, 68 so that there is free space between the rollers 41, 48 and the riffle board. In other words, the nip is provided between the ends of the pivotal members 33, 37 and respective rollers 41, 48, and this nip may be opened after feeding by the rollers 41, 48 by rotation of the pivotal members 33, 37. The first position in which the pivotal members 33, 37 are in close engagement with the rollers 41, 48 is illustrated in solid lines in Fig. 2 and the second withdrawn position is illustrated in dotted lines.

In a preferred arrangement, the solenoid 66 may be controlled by the control logic of the apparatus to which the sheet feeder feeds sheets. Thus when the apparatus is ready to receive paper from the sheet feeder, it may automatically send a signal to the solenoid 66 to withdraw the pivoted members 33, 37.

To further reduce the resistance to move- ment of the paper out of the paper feeder the spring fingers 53 and pivoted finger 52 are deleted.

Claims

1. A sheet feeder for feeding single sheets from a stack of sheets comprising first drive means, a feed path including an edge, the first drive means being arranged to engage the top sheet of a stack of sheets and to drive said top sheet forwardly along the feed path to the edge, a second drive means for pulling said sheet over said edge, and means to drive the second drive means so as, in use, to urge the sheet along the path at a higher speed than the first drive means.

2. A sheet feeder as claimed in claim 1 in which the lower surface of the path comprises a friction material.

3. A sheet feeder as claimed in claim 2 in which means is provided to urge the second drive means and the path towards one another.

4. A sheet feeder as claimed in claims 1, 2 or 3 further comprising a second edge with a third driving means for pulling the sheet over the second edge and means to drive the third driving means so as, in use to urge the sheet along the path at a higher speed than the second drive means.

5. A sheet feeder as claimed in claim 4, in which means is provided to urge the third driving means and the path towards one another.

6. A sheet feeder as claimed in any of claims 1 to 5 in which the means to drive the second and/or third drive means is adapted in use to urge the sheet along the path at a speed which is at least 10% faster than the preceding drive means.

7. A sheet feeder as claimed in any of claims 1 to 6 in which means is provided to urge the first drive means and the stack towards one another.

8. A sheet feeder as claimed in any of claims 1 to 7 in which each drive means comprises rollers or wheels, the peripheral surfaces of which carry friction material.

9. A sheet feeder as claimed in any of claims 1 to 8 in which pivoted members are provided to define the path adjacent each drive means, the pivoted members being urged into engagement with the adjacent drive means.

10. A sheet feeder as claimed in claim 9 in which the or each pivoted members are movable to an alternative position in which they are spaced away from the adjacent drive means.

11. A sheet feeder as claimed in claim 10 in which means is provided to move the or each pivoted member to its/their alternative positions, said means being controllable, in use, by a signal from apparatus to which the sheet feeder, in use, feeds the sheets.

1 2. A sheet feeder as claimed in any of claims 1 to 11 in which the angle of the or each edge is greater than about 10 .

1 3. A sheet feeder as claimed in claim 1 2 in which the angle of the or each edge is 30-40".

14. A sheet feeder as claimed in any of claims 1 to 1 3 including means provided to attach said sheet feeder to the apparatus to which, in use, the sheets are to be fed.

1 5. A sheet feeder as claimed in claim 1 substantially as hereinbefore described with reference to Fig. 1 or Fig. 2 of the accompanying drawings.