The invention relates to a sorter unit for sorting single sheets into bins, the sheets being supplied consecutively from a sheet processing machine, such as an electrophotographic printer or a copying machine, said sorter unit being of the type in which the bins are positioned in succession along a sheet feeding path and in which conveyor means advance each sheet along the feeding path to a guide means which is controlled by signals from a control unit and leads the sheet to be distributed into a selected bin, the guide means being, with the view of being positioned on a level with the selected bin, displaceable along the sheet feeding path opposite the pertaining bins.

Such a sorter unit is disclosed in US patent No. 4 273 326, in which the bin bottoms are equidistantly spaced apart so that the bins have the same size. The guide means is secured on two endless belts travelling over two guide rollers positioned at either end of the section of the sheet feeding path opposite the bins and the guide means has a curved guide plate whose one end section engages the sheet feeding path and whose other end section extends substantially in parallel to the bottom of the bins. One of the guide rollers carries a cam wheel which upon activation by a pawl rotates the guide roller and thus displaces the guide means a pre¬ determined distance actually corresponding to the distance between two consecutive bins. The permanent bin size sets an upper limit to the number of sheets that may be sorted into each bin. It is the object of the invention to provide a sorter unit which in a simple manner may be adapted to the actual use requirements, also after the sorter unit has been delivered to the user.

This is obtained in that the sorter unit is characterized in that at least one of the bins has an

adjustable maximum sheet capacity, that each adjustable bin is provided with a signalling device to indicate the positioning of the bin bottom along the sheet feeding path and that the guide means is positionable in relation to the bottom of the adjustable bin when sheets are to be into it.

The invention recognizes that on the site of use there may arise a need for changing the peak sheet capacity of one or more bins. In some cases there may further be a requirement for sorting a large number of sheets into a single shelf. When the sheet processing machine is a centrally located printer of a multiuser system, in which the users have varying needs for printer capacity, it is possible, by virtue of the adjustable sheet capacity of the bins, to obtain a complete adaptation of bin sizes according to the indi¬ vidual user's need. The signalling device for indicat¬ ing the positioning of the bin bottoms along the sheet feeding path makes it possible to position the guide means in relation to the individual bin, even though the bin heights vary along the sheet feeding path.

In a preferred embodiment the control unit can control the distance of the guide means from a bin bottom in such a manner that the distance increases substantially in step with the height of the pile of sheets discharged into the bin. This makes it possible to sort by and large an unlimited number of sheets into a single bin, the guide means being moved away from the bottom concurrently with the increase of the pile of sheets. Full advantage may then be taken of the adjust¬ able bin size because it is possible without the risk of erroneous piling to discharge considerably higher piles into a bin than in prior sorter units.

If the control unit sets the guide means a pre- determined distance far remote from the bin bottom every time a predetermined number of sheets has been

discharged into the bin after the latest height sett¬ ing, the drive of the guide means may in an advantage¬ ously simple manner be a stepping motor in which a single setting step corresponds to the piling height of the predetermined number of sheets.

If it is desired to sort larger stacks of sheets into more bins the adjustable bins may advantageously include a sensor to emit a "bin empty" signal to the control unit when there are no sheets in the bin. The control unit may then in a simple manner memorize the height of the sorted sheet piles, thereby positioning the guide means from shelf to shelf for the delivery of supplementary sheets immediately atop the piles.

When the sorter unit is of the type in which the conveyor means include a number of endless belts running over at least two guide rollers positioned at either side of the section of the feeding path opposite the bins, and in which the guide means includes an arcuate guide plate whose one end section is positioned at said path section on the side of the belt facing away from the bins and extends substantially parallel thereto, and whose other end section is positioned on the bin side of the belt and extends substantially parallel to the bottom of the bins, the guide means may comprise a slide block which rides in a slot parallel to the path section opposite the bins, and the slide block may carry the guide plate as well as a pair of idler rollers disposed on either side of the belt and being in contact therewith. This embodiment is particularly advantageous when big piles are to be sorted into a single bin because the slide block and the slot offer a precise control of the distance of the guide means on to the array of bins and the two idler rollers offer an accurate infeed of the sheet at the top of the pile. In view of the fact that the idler rollers are positioned at either side of the belt, they

are driven in an extremely simple manner by the belt and there is no need for a separate drive for the rollers, thereby minimizing the weight of the movable guide means so that it may be quickly accelerated during the necessary setting movements.

As indicated above the idler rollers contribute to precisely delivering the sheet into the selected bin without the risk of sheet cockling in the free space between the end of the guide plate and the inlet opening of the bin. This is inter alia due to the fact that the idler rollers are positioned at a short distance from the guide plate and will guide the sheet into engagement between the belt and the roller posi¬ tioned on the bin side of the belt, thereby guiding the sheet without the risk of lateral cockling when its leading edge meets the guide plate.

With the view of considerably simplifying the adjustment of the size of the individual bins several of the bin bottoms mounted in a housing may be detach- able and each of the detachable bin bottoms may be carried by supporting members accommodated within the housing so that the detachable bottoms may optionally be inserted at a suitable place in the housing. When the user wants to alter the size of one or more bins, the associated bin bottoms are simply lifted out, following which they are reinserted in the positions corresponding to the desired sheet capacities. Such a resetting of the sorter unit may be effected in a few minutes without the use of tools. Embodiments of the invention will now be des¬ cribed in detail with reference to the very schematical drawings, in which

Figs 1 and 2 illustrate, in side elevations, sheet handling machines with sorter units according to the invention,

Fig. 3 is a side elevation of a sorter unit according to the invention,

Fig. 4 on a larger scale a schematic diagram of the guide and the feeding means of the unit in Fig. 3, viewed from the opposite side,

Fig. 5 is a sectional, perspective view of the guide means in Fig. 4,

Fig. 6 is a sectional, perspective view of the unit in Fig. 4, and

Fig. 7 is a strongly simplified side elevation of an embodiment fitted for double faced sheet print- ing.

A sheet processing machine, e.g. a printer, a photocopier or a telecopier, is in Figs 1 and 2 shown as a subunit 1 in a framing also comprising a sheet feeder 2 and a sorter unit 3 according to the invention, which sorter unit 3 may have horizontally positioned bins (Fig. 1) or tilted bins (Fig. 2) as shown in dotted lines,

From sheet feeder 2 single sheets are supplied along path A to the sheet infeed of machine 1 and after printing or copying the sheets leave the sheet outlet of the machine and are guided along a sheet feeding path B into bins 4 of the sorter unit.

A sorting bin is selected for each individual sheet in dependence on information in a control signal pertaining to the sheet and emitted from machine 1.

Sorting methods may for instance consist in multiplying a document and sorting the individual copies into their respective bins or in the production of originals and sorting then into a bin allocated to a specific person. Machine 1, sheet feeder 2, the supply of sheets along path A and the creation and transmission of the control signal are well known techniques that will not be described here. It shall only be mentioned that the machine 1 may be of any arbitrary structure on condition that it discharges single sheets at a time interval between each sheet.

The framing may be open into bins 4, thereby providing free access for manually removing the sheets from the bins or the access may be barred by a door covering a number of bins. The illustrated design is compact and occupies merely a small floor area and at the same time there is immediate access to all units of the framing.

In the embodiment of sorter unit 3 illustrated in Fig. 3, shelves 4 are vertically superposed in a frame composed of sheet metal members, such as a top covering 5, an end wall 6, a bottom 7 and two lateral members 8 positioned at either side of the unit and kept at a permanent, mutual distance by means of stiffeners, not shown. End wall 6 is at either side provided with an angular flange 9 extending parallel to side members 8. The sheet metal members are interconnected through spot-weldings 10, screws or similar fastening means.

Each bin 4 consists of a sheet metal bottom on which the sheets may be disposed. The size of the bin is determined by the distance up to the superposed bin bottom and is selected in dependence on the desired sheet capacity. The bin bottom is at each of its four corners supported by the frame which is illustrated in Fig. 3 by marks 11, which may for instance be screws securing a bent lobe on the bottom to the frame. As an alternative, marks 11 may illustrate rod members to be releasably fastened by spring engagement with holes in side members 8 and flange 9. The bin bottom is disposed on the rod members and if the need arises for altering the sheet capacity of the bin when using the sorter unit, the associated rod members may be moved to a new vertical position in the framing.

In Fig. 3 a sheet 12 is being fed to the sorter unit while another sheet 13 is being delivered atop a pile of sheets 14 in a bin. The sheet 12 is

received in an inlet passage consisting of an outer delimitation plate 16 and an inner delimitation plate 17 both of which are secured to side members 18. Opposite the sheet discharge of machine 1 plates 16 and 17 extend mainly horizontally, whereas in the direction away from the discharge they are smoothly curved downwards until they extend downwardly towards the conveyor means of unit 3, as will be described in the following. The conveyor means carries the sheet to a guide means leading the sheet into the selected bin. For each side member 8 the guide means com¬ prises a slide block 18 that is vertically dis- placeable in a slot 19 provided in the side member. The slide block is secured to an endless belt 20 running over a pulley wheel 21 at the top edge of the slot and a drive pulley 22 at the lower edge of the slot.

From a control unit 23 and through a wire 24 a stepping motor 25 receives signals for setting the guide means opposite the selected bin. The setting movement is transmitted through a driving belt 26 to the drive pulley 22 and belt 20.

The conveyor means are driven by a motor 27 which through a driving belt 28 and a pulley wheel 29 drives a secondary roller described later on. Control unit 23, e.g. a programmed microprocessor, is through a conduit 30 in communication with the sheet handling machine 1 and receives from it sorting control codes for the supplied sheets 12. On this basis discrete setting signals are emitted to the stepping motor 25 and through a wire 31 signals for initiating or stopping drive motor 27.

The two drive pulleys 22 are fastened on their respective pins of a shaft 32 (Fig. 4) and the two pulley wheels 21 are secured on their respective pins of a shaft 33. Shafts 32 and 33 extend between

side members 8 and are journalled therein. Bushings 34 are coaxially journalled on shafts 32 and 33, possibly by means of roller bearings and, coaxially with the bushings a number of pairs of an upper guide roller 35 and a lower guide roller 36 is secured. The pair of guide rollers carries an endless belt 37 extending past the inlet openings of the bins.

For each pair of guide rollers there is a secon¬ dary conveyor roller 38a, 38b on either side of the lower guide roller 36 and vertically beneath the lower guide roller there is a third secondary conveyor roller 39. An endless contacting belt 40 travels over the three secondary conveyor rollers and is in contact with belt 37 along the lower half of the cir- cumference of guide roller 36. The three rollers 38a, 38b and 39 are secured on their respective rotational shafts 41, 42 and 43 which parallel to shaft 32 extend between and are journalled in side members 8.

Pulley wheel 29 is secured on the pin of shaft 43 and motor 27 rotates said shaft in the direction of arrow C. The secondary conveyor roller 38a thus drives belt 40 in the direction of arrow D and the two remaining rollers 41 and 42 in the same rota¬ tional direction as itself. Due to the fact that belt 40 is in close con¬ tact with belt 37, said two belts will be moved simultaneously mainly without slip, meaning that the section of belt 40 opposite the inlet openings of the shelves will be moved vertically upwards in the direc- tion of arrow E.

The lower end edges of the delimitation plates 16, 17 extend parallel to shaft 32 and at a short distance from each other immediately above the gap bet¬ ween guide roller 36 and conveyor roller 38b so as to form an outlet slit 44 for the supply passage 15 to ensure a precise delivery of sheet 12 down between belts 37 and 40.

Upon landing in the gap sheet 12 is grasped between the belts and drawn round along the lower sec¬ tion of guide roller 36, following which the sheet will be pushed up into a vertical guide slit 45 between belt 37 and a guide wall 46 which is sta¬ tionary in relation to the bins and extends vertically upwards at a short distance from and on the bin side of belt 37.

As mentioned, the guide member includes two slide blocks 18 accommodated in a slot 19 on their respective side members. The slide blocks are inter¬ connected by means of two rods 47 positioned opposite each other on either side of belt 37 (Fig. 5). Either end of rod 47 is passed through a hole in the slide block and a Seeger circlip 48 is at the external side of the block inserted in a circumferential groove in rod 47 in order to prevent axial displacement thereof.

A plastic wheel 49 is journalled on rod 47 opposite belt 37 and the plastic wheel has such a diameter that its periphery bears against the side of the belt whose opposite side is in contact with a corresponding plastic wheel 50 on the other rod 47. Plastic wheels 49 and 50 operate as idler rollers positioning the belt between them and being rotating when the belt is moved.

The slide block includes on the internal side of each of the opposite vertical sides a recess 51 of such a depth that the intermediary projection 52 has a width corresponding to the width of slot 19. Pro¬ jection 52 is embedded in the slot and guides the block into a translatory motion parallel to belt 37. The slide block is secured to belt by means of clamping members 53 tightened by screws 54 on the external side of the block at such a mutual short distance and on either side of the belt (not shown in Figs 4 and 5) that the belt is fastened to the block.

A side wall 55 of sheet metal extends between the two blocks 18 and is secured on the inner side thereof at a short distance from wheel 50 positioned on the bin side of belt 37. The wall extends at a short distance from the belt vertically down to the bin side of guide wall 46 and has a length larger than the maximum distance the slide block may be moved away from the upper edge of wall 46. When the guide member changes its setting opposite the bins, walls 46 and 55 will be pushed together or pulled away from each other so that guide slit 45 always extends from roller 38a to wheel 50. Side wall 55 has recesses extending from the lower edge and a suitable distance upwards in the areas opposite roller 38a so that the wall pass by the roller.

A guide plate 56 extends between slide blocks 18 and is secured to their internal side. The guide plate is made from sheet metal bent into shape and includes a lower end section 57 extending substan- tially parallel to the belt apart from an edge area where the plate is bent in the direction away from the belt. End section 57 merges through an intermediate section extending past the course of the belt into an upper end section 58 extending substantially parallel to bins 4. The guide plate is smoothly bent with a concave curvature viewed from guide slit 45. In the area around the belt the guide plate has at its top and central section a cutout 59 offering space for the belt to pass and for the wheel 49. When the sheet, as described above, is pushed up through the guide slit (in the direction of arrow F in Fig. 5) wall 55 guides the leading edge of the sheet into the conveyance gap between the belt and wheel 50 where the sheet is grasped and lifted upwards. Under the continued movement of the sheet the leading edge impinges on guide plate 56 deflecting the sheet and guiding it into the selected shelf.

Fig. 6 shows a strongly simplified sketch of an embodiment with three belts 37 with associated guide rollers and contacting belts 40. The belts are spaced apart in such a manner that the two extreme belts 37 catch the sheet at its longitudinal, peripheral areas while the central belt catches the middle of the sheet. The use of three rollers ensures that the sheet remains plane in the transverse direction under the conveyance and sorting. A stationary first signalling device 60 (see Fig. 4) may be positioned at a predetermined place at a bin 4 and the guide means may carry a second sig¬ nalling device 61, when a reference point for the ad¬ justment of the guide member is wanted. The signalling devices are connected through wires with control unit 23 and when they are opposite each other they emit a positioning signal that the control unit may use e.g. for setting at zero index a scaling circuit for step pulses to the stepping motor. Each bin may also be provided with a first signalling device to be used in the positioning of the guide member opposite the bin. In this case the stepping motor may be replaced by an ordinary electro¬ motor which stops upon receiving a positioning signal from the selected bin.

As the size of the bins may be adjusted on site of use, it may be desirable to make use of a first sig¬ nalling device for each bin to ensure that the control program all the time knows in which height the bin bot- toms are positioned.

If the signalling devices are optical the first device may be a simple reflex strip on the front edge of the bin while the second signalling device is adapted to emit as well as to receive the light signal. When a vast number of sheets are to be sorted into a single bin the guide member is firstly posi-

tioned as in the case of empty bin. The control system records the number of sorted sheets and every time a predetermined number of sheets has been sorted, the guide member is moved a predetermined distance further up so that the sheets are delivered without any problem atop the stack. Up to for instance 500 to 600 sheets may in this manner be sorted into a stack. The control unit memorizes the number of sheets sorted into the bin until it is emptied and a sensor emits a "bin empty" signal to the control unit.

Double faced sheet printing may be realized in a simple manner by supplementing the above described sorter unit with a second set of sheet conveyor means and sheet guide means replacing the above end wall 6 and being positioned laterally reversed in relation to the first set of sheet conveyor and guide means. As it will appear from Fig. 7 the second set is extended so that its pulley wheel 21 is positioned at a higher level than a sheet inlet 62 for refeeding sheets into machine 1 so that the guide means may be positioned opposite inlet 62.

One or more of bins 4 is/are designed as a sheets through-flow bin 4' that is open at both ends and may include sheet stopping and feeding means for stopping and retaining, in dependence on control signals from unit 24, a sheet received in the bin or to send on the sheet to be delivered at another set of conveyor means. Such means, not shown, may for instance be wheels positioned above the bottom of the bins and which are rotatable about a horizontal axis and have radially projecting flexible carrier fingers touching the upper side of sheets in the bin.

The second set of conveyor and guide means include the same subcomponents as the first set. The sheets for double faced printing are deli¬ vered in an ordinary way into the sheets through-flow

bin 4'. When it is desired to refeed the sheet into machine 1 , the guide plate 56' is positioned oppo¬ site the outlet end of bin 4' and the feeding means of the bin are activated to deliver the sheet to the second set of conveyor means whose contacting belts 40' are driven in the direction shown by the arrow G. The sheet impinges on guide plate 56' and will be drawn down into the associated guide slit until it gets completely clear of bin 4', following which control unit 23 stops the conveyor means and controls guide plate 56' to be positioned in the delivery position opposite the sheet inlet 62. The contacting belt 40' is initiated in the reverse travelling direction according to the arrow H, thereby conveying the sheet vertically upwards to be delivered at inlet 62.