Device for delivering, depositing, and aligning sheets in a stack container

Abstract: The invention relates to a device (1) for delivering, depositing, and aligning sheets (S) in a stack container (2) of an apparatus (3) by means of sheet delivery means (4), sheet deposition means (5), sheet alignment means, and sheet hold-down means that are driven in circulating fashion such that the alignment means and hold-down means are components of the deposition means, and the delivered and deposited sheets (S, S') can be aligned against a sheet stop (21) lying at right angles to the sheet delivery direction (X) and can be held down on the sheet stack (ST). To create a device which allows precise, reliable, and rapid stacking of sheets, the sheet deposition means (5) are configured in separately controllable fashion, and for completely guided lowering and deposition of a delivered sheet (S); moreover, the sheet deposition means (5), the sheet alignment means, and the sheet hold-down means can be operated in discontinuously circulating fashion and in synchronism with sheet delivery, and the sheet deposition means (5) have conveying means (50) having at least one resilient finger (51, 51') for carrying a delivered sheet (S) such that by means of the fingers (51, 51') during their lowering movement, a delivered and fed-in sheet (S) is carried at one of its end regions (Sy) and can be lowered and deposited onto the sheet stack (ST) in uniform and completely guided fashion.

Description: The invention relates to a device for delivering, depositing, and aligning sheets in a stack container of an apparatus by means of sheet delivery means, sheet deposition means, sheet alignment means, and sheet hold-down means that are driven in circulating fashion such that the alignment means and hold-down means are components of the deposition means, and the delivered and deposited sheets can be aligned against a sheet stop lying at right angles to the sheet delivery direction and can be held down on the sheet stack. US Patent 4,883,265 discloses a device of the aforesaid kind for delivering, depositing, and aligning sheets in a stack container. The sheet deposition, sheet alignment, and sheet hold-down means are configured in combined fashion as at least a single toothed belt, configured in the form of an endless loop, having teeth arranged on its inner side. The toothed belt is arranged around a toothed pulley which is mounted centeredly on a drive pulley, located below, of a sheet infeed roller pair of the sheet delivery means. The toothed belt, which projects with its free loop region into the stack container, is secured in position by means of a contact roller of the sheet infeed roller pair on the one hand with its upper belt portion on the toothed pulley and by means of a rotation or circulation effected by means of the drive pulley, and on the other hand is pressed with its lower belt portion onto the sheet deposition surface or the sheet stack. In this context, the free loop region of the toothed belt constitutes, with its outer side of its upper belt portion in the region of the toothed pulley, a transport surface, running substantially horizontally and parallel to the sheet deposition surface, for a sheet delivered by means of the sheet infeed roller pair. For reliable transportation of the sheet, the outer side or transport surface has an elevated coefficient of friction. After it has been released by the sheet infeed roller pair, the delivered or fed-in sheet, carried at its rear end region by the upper belt portion, is fed farther into the sheet stack, lowered, and deposited onto the sheet deposition surface or onto the sheet stack. Because the sheet stack container is arranged with a downward tilt at its sheet deposition surface end which faces against the sheet delivery direction, the delivered sheet slides back, opposite to the sheet delivery direction, against the toothed belt which continues to circulate. The delivered sheet is thereby grasped by the lower belt portion and transported and aligned, opposite to the sheet delivery direction, against a front wall of the stack holder that is configured as a sheet stop and tilted against the sheet delivery direction. Arranged in the region above the upper belt portion is a pressure means which presses the delivered sheet onto the upper belt portion while it is being fed in. It is disadvantageous that the delivered or fed-in sheet is not guided to the point of complete deposition or to the deposition surface during its lowering and deposition movement, so that on the one hand an imprecise lateral alignment is possible as the sheets are being stacked, and on the other hand an inclined collection container is necessary in order to bring the delivered sheet once again into the region of influence of the tooth belt for alignment. The consequence of the latter, together with a longer infeed path resulting from the toothed belt, is a longer sheet infeed time. It is also disadvantageous that the toothed belt circulates continuously, which, when thin sheets are being aligned and held down, can lead to compression (creasing, waving, etc.) of the sheets at the sheet stop, or, regardless of the sheet thickness, to elevated material abrasion. A further disadvantage is that the toothed belt for aligning and holding down sheets does not act on the sheets at the outermost end of the delivered sheets or not directly at the sheet stop, which can result in the sheets being pushed up at the stop. U.S. Patent 5,692,740 discloses a rotatable disks type sheet inverting, a registration and stacking system. The system has finger units with sheet carrying slots which are mounted to the disk units. A vertically movable sheet hold down bail system is automatically actuated in coordination with the release of the sheet to only engage the sheet when it is very closely adjacent to the top of the stack. The sheets are stacked in an inverted orientation. Furthermore, no speed adjustment is possible so that the sheets are transported with the same relative speed. It is therefore the object of the invention to create a device which does not have these disadvantages cited above, but rather allows precise, reliable and rapid stacking of sheets, while at the same time guaranteeing a simple, compact configuration and operation in an automated environment. According to the invention, the object is achieved by means of a device as defined in Claim 1, in that the sheet deposition means are configured in separately controllable fashion, and for completely guided lowering and deposition of a delivered sheet that is fed into the stack container. Advantageously, the sheet deposition means can be operated by means of a drive unit controllable separately from the sheet delivery means in such a way that the sheet deposition means can be moved at a lowering speed which is the same as or slightly less than the falling speed of the delivered sheet. Also advantageously, the sheet deposition means, sheet alignment means, and sheet hold-down means can be operated in discontinuously circulating fashion and in synchronism with sheet delivery, and the sheet deposition means have conveying means having at least one circulating, resilient finger for carrying a delivered sheet, such that by means of the finger during its lowering movement, a delivered sheet is held at one of its end regions and can be lowered and deposited onto the sheet stack in linear and uniform fashion. In addition, advantageously, the resilient finger(s) is/are arranged in a perpendicularly projecting alignment on one or more circulating belts running parallel and extending in the stacking direction of the sheets; each finger has at its fingertip a lower and an upper surface region with an elevated coefficient of friction; and each resilient finger is additionally configured as an alignment means and hold-down means. Moreover, advantageously, the sheet deposition means are arranged on the one hand in the region of a sheet infeed roller pair of the sheet delivery means and on the other hand in the region of a rear wall of the collection container lying in the sheet delivery direction and configured as a sheet stop, in such a way that the sheet deposition means are movable in the stacking direction directly along the rear wall or along the sheet stop, and in addition the sheet stop is arranged with its upper edge tilted against the sheet delivery direction and toward the sheet deposition means. Furthermore, advantageously, the sheet deposition means have in the region of the sheet delivery means a controllable sheet pressure means which coacts with the sheet deposition means as the sheet begins to be lowered. Further features and advantages are evident from the description of the embodiments of the invention depicted in the drawings, and from the additional dependent claims. The drawing shows in Fig. 1 the device according to the invention in an apparatus in a three-dimensional depiction of the region of a sheet stack container, all elements of the apparatus not essential to the invention being omitted; Fig. 2 the device according to the invention as shown in Fig. 1 in a schematic side view, the device being depicted in a sheet delivery position or starting position with sheet deposition means in an initial position; Fig. 3 the device according to the invention as shown in Fig. 2, a portion of the deposition means being depicted in an upper sheet catching position with a sheet resting thereon and spaced against the sheet stack in the stacking direction; Fig. 4 the device according to the invention as shown in Figs. 2 and 3, the sheet deposition means being depicted in a sheet deposition position on the sheet stack. The following description based on Figs. 1 through 4 refers to a preferred embodiment of device 1 according to the invention for delivering, depositing, and aligning sheets S in a stack container 2 of an apparatus 3 by means of sheet delivery means 4, sheet deposition means 5, sheet alignment means, and sheet hold-down means that are driven in circulating fashion such that the alignment means and hold-down means are components of the deposition means, and the delivered and deposited sheets S, S' can be aligned against a sheet stop 21 lying at right angles or transversely to sheet delivery direction X and can be held down on sheet stack ST. In this context, the device is used in an apparatus (not shown) of known type, for example in a copier, and is preferably used to output completed customer-specific copying jobs. It is self-evident to one skilled in the art that the invented device is also usable in other apparatus, for example in printers, printing presses, or sheet-sorting apparatus; that the sheet stack container can also have, in addition to the inclined arrangement depicted and described below, a non-inclined horizontal arrangement; and moreover that sheets of various types, for example paper, board, or film, of various thicknesses, sizes, and weights, can be utilized. As depicted in Figs. 1 through 4, sheet delivery means 4 have on the one hand a sheet delivery roller pair, arranged toward the interior of the apparatus, with lower drive roller 42 and upper pressure roller 43, and on the other hand a sheet infeed roller pair, arranged in sheet delivery direction X toward the exterior of the apparatus and toward sheet stack holder 2, with lower drive roller 40 (made, for example, of foam) and upper pressure roller 41. Associated with both roller pairs 40, 41; 42, 43 is a common drive unit 6, controllable by a microprocessor control unit (not shown), which has a stepping motor or servomotor 60, with or without gear train, connected to drive roller 40 of sheet delivery roller pair 40, 42, and a drive belt 61 between sheet delivery drive roller 40 and sheet infeed drive roller 42 (Fig. 2). As shown in Fig. 1, drive roller 42 and pressure roller 43 of sheet infeed roller pair 42, 43 consist of two rollers spaced apart axially next to one another. Arranged in front of the sheet delivery roller pair, as shown in Fig. 2, is a sensor 62 by means of which a sheet delivered from the apparatus can be detected at its front edge, and drive unit 6 can be activated in conjunction with the apparatus control unit. Stack container 2 is configured in the form of a rectangular box open at the top and matched to the sheet formats, the rear wall of the stack container, oriented transversely to and against the sheet delivery direction X, being provided as sheet stop 21. Sheet stack container 2 is mounted in inclined fashion in the apparatus, so that its sheet deposition surface 20 slopes downward opposite to sheet delivery direction X, and sheet stop 21 is tilted, with its upper edge 21.1 facing in stacking direction Z, opposite to sheet delivery direction X and toward sheet deposition means 5 (approx. 4 degrees). Sheet deposition means 5 are arranged on the one hand in the region of sheet infeed roller pair 42, 43 of sheet delivery means 4, and on the other hand in the region of rear wall 21 of collection container 2, in such a way that sheet deposition means 5 are located directly along the rear wall at an acute angle corresponding to the tilt of the sheet stop, and can be moved up and down in stacking direction Z. Sheet deposition means 5 include conveying means 50 which, in the embodiment according to the invention, each have two resilient, i.e. bendable, fingers 51, 51' on two belts 52 which are arranged next to one another, extend parallel to or in stacking direction Z, and circulate around drive pulleys 54 and idler pulleys 55, for carrying, lowering, and depositing a delivered sheet S (see Fig. 1). The two resilient fingers 51, 51' of each belt are arranged, spaced one-half belt length (180 degrees) apart from one another, on the outer periphery or outer surface of belt 52 in a perpendicularly projecting alignment, such that the fingers of the two belts, arranged in alignment next to one another, constitute a first/upper 51 and a second/lower 51' finger pair, and belts 52 can be drive synchronously in a circulating direction clockwise or opposite to stacking direction Z (see Figs. 2 through 4). Fingers 51, 51' - which for example can, like the belts, be configured of a plastic material - have at their fingertips, viewed in the circulating direction, a front/lower 51.1 and rear/upper 51.2 surface region with an elevated coefficient of friction. Fingers 51, 51' furthermore have a length, projecting into the region of stack container 2, which has a predetermined relationship to the sheet length and to a sheet ejection speed (to be explained later). Idler pulleys 55 of the two belts 52 are arranged on drive shaft 44 of sheet infeed drive roller 42 in freely rotatable fashion by means of ball bearings and on either side of said sheet infeed roller 42 (see Fig. 1). Belt idler pulleys 55 and belt drive pulleys 54, i.e. belts 52 with fingers 51, 51', are arranged at an axial distance from one another such that a delivered and fed-in sheet S having a predetermined minimum width can be carried, lowered, and deposited. Idler pulleys 55 of belts 52 have a smaller outside diameter as compared with sheet infeed drive roller 42, so as not to come into contact with sheet S while it is being delivered or fed in (see Figs. 1 through 4). To prevent any sheet contact with resilient fingers 51 while sheet S is being delivered and fed in, guide panels 53, for deflecting or bending aside the circulating fingers 51, 51' as they pass through this region, are arranged above belt idler pulleys 54 and belts 52, and below a supporting peripheral surface of sheet infeed drive roller 42. As shown in Fig. 2, belt drive pulleys 54 for the two belts 52 are mounted in the region in front of a lower edge 21.2 of sheet stop 21 or of the rear wall of stack container 2, on a rotatable drive shaft 56. Belt drive shaft 56 or belt drive pulleys 54 is/are drivable clockwise, separately from sheet delivery means 4, by means of a further drive unit 7, said drive unit 7 also having a microprocessor-controlled drive motor 70 with or without gear train. In this context, belt idler pulleys 55, like belt drive pulleys 54 of conveying device 50, are configured as smooth belt pulleys or toothed-belt pulleys in accordance with the embodiment of belts 52 (smooth belts or toothed belts). Sheet stop 21, i.e. the front wall of stack container 2, has recesses 22 for the resilient fingers 51, 51' or finger pairs 51, 51' extending along the movement path of the fingers and parallel to stacking direction Z (see Fig. 1). Recesses 22 form an inlet to stack container 2 for fingers 51; 51' or finger pairs 51; 51', so that by means of fingers 51; 51', lying respectively next to one another, of deposition means 5, during their downward movement effected by belts 52 circulating in controlled fashion, a delivered/fed-in sheet S is held and supported at its rear end region Sy and, guided uniformly and completely, can be lowered and deposited linearly onto sheet deposition surface 20 or onto sheet stack ST in stack container 2. Sheet stop 21 or the front wall of stack container 2 thus consists substantially, as shown in Fig. 1, of two vertically oriented sheet stop struts 21 spaced horizontally apart. Resilient fingers 51, 51' are provided not only as deposition means 5 but also as alignment and hold-down means, and are correspondingly configured as already described, so that the two resilient fingers 51, 51' located next to one another can be respectively lowered by means of conveying means 50 onto an outermost rear end region STy of sheet stack ST and moved downward past its end face, as the fingertips bend up, in such a way that in addition to the lowering and deposition of the delivered/fed-in sheet S, the latter can also be moved by fingers 51, 51' by means of their upper friction surfaces 51.2, so as to align against sheet stop 21, and a previously deposited sheet S' can be held down on sheet stack ST by means of said fingers 51, 51' and moved by means of their lower friction surfaces 51.1 so as to align against sheet stop 21 (see Fig. 4). As shown in Figs. 1 through 4, sheet deposition means 5 have, above belts 52 of conveying means 50 and sheet infeed drive roller 42, sheet guide means 8 which guide a sheet S, while it is being fed in, onto a finger 51 (or finger pair 51) located in an upper sheet catching position, so that when sheet S has been completely fed in, it rests with its rear end region Sy on fingers 51. The manner of operation of the device is as follows: Proceeding from an assumed starting position shown in Fig. 2 - a sheet delivery position of device 1 in which a depicted sheet S is delivered by means of sheet delivery roller pair 40, 41 to sheet infeed roller pair 42, 43 in sheet delivery direction X to the stack container, and in which an upper or first pair of adjacently located fingers 51 of sheet deposition means 5 is located in an upper starting position or initial position, and the lower pair of fingers 51', lying next to one another, is located in a lower initial return position - the two roller pairs 40, 41; 42, 43 of sheet delivery means 4, controlled by the apparatus control unit, are operated synchronously and at a predetermined high rotation speed or at a predetermined high sheet delivery speed, by means of common drive unit 6. Once sheet S has been delivered or fed in sufficiently that only the rear end Sy of the sheet is still between sheet infeed roller pair 42, 43 (not depicted), the rotation speed of the two roller pairs 40, 41; 42, 43 is set to a low value (e.g. a value ten times lower) corresponding to a predetermined sheet ejection speed. Before the delivered sheet S is released by sheet infeed roller pair 42, 43, the upper, first finger pair 51, controlled by the apparatus control unit and circulating clockwise by means of the further drive unit 7 associated with it, and driven at a low initial speed through guide panels 53, has ended up in a substantially horizontal position (the sheet catching position) in the upper open region of recesses 22 between sheet stop struts 21. After sheet S has been released by sheet infeed roller pair 42, 43, it is laid with its rear end region Sy, under its own weight (i.e. because of gravity), and guided by the front ends of sheet guide tongues 80, onto upper finger pair 51; the fed-in sheet S, with its front end region Sx, is at a distance above the sheet deposition surface of stack container 20 or above an already existing sheet stack ST, and is not yet touching the latter. In the meantime, after the first fed-in sheet S has been released, drive unit 6 of sheet delivery means 4 is switched by the control unit to an intermediate sheet transfer speed (e.g. one-third of the value), said sheet transfer speed corresponding to the sheet transport speed inside the apparatus. Then, as shown in Figs. 3 and 4, the upper, first finger pair 51 with sheet S is lowered vertically - at an elevated and substantially constant speed (a "lowering speed") and, because of belts 52, in linear and uniform fashion - onto sheet deposition surface 20 of stack container 2 or onto an already stacked sheet stack ST The lowering speed selected is, in this context, the same as or less than the falling speed of sheet S, so that sheet S can at all times keep up with finger pair 51 as it moves downward, and can be lowered and deposited in a completely guided fashion. The lowering speed of the upper finger pair 51 is controlled, in this context, by the apparatus control unit as a function of the sheet type that is used and sensed, i.e., for example, at a somewhat slower lowering speed for very light sheets. As shown in Fig. 4, during the lowering movement of sheet S, the latter is moved with its rear end Sy, due to the vertically tilted arrangement of sheet stop 21 and the resulting relative movement Y of sheet S, against sheet stop 21, thus resulting additionally in a sheet alignment. The sheet alignment is promoted or enhanced by upper friction surface 51.2 of fingers 51. As the upper, first finger pair 51 moves farther downward, Figs. 2 and 4 show that the lowered sheet S is deposited and further aligned, and sheet S' previously deposited onto sheet stack ST is held down and aligned, by the fact that the upper, first finger pair 51 lies on the outermost edge of the sheet stack or on sheet deposition surface 20, executes a further relative movement Y against sheet stop 21 and horizontally against sheet stack ST, and thus moves past the rear end face or the sheet stack, or lower edge 21.2 of sheet stop 21, as the fingertips bend up. In this context, alignment of the previously deposited sheet S' is effected by lower friction surface 51.1 of fingers 51. As shown in Fig. 4, during lowering of the first fed-in sheet S a further sheet Sn, controlled by sensor 62, is delivered first at the intermediate sheet transfer speed and, after being completely picked up by sheet delivery roller pair 40, 41 and sheet infeed roller pair 42, 43, at the high sheet delivery speed, in order to gain time for the slower lowering and deposition of the fed-in sheet S that is limited by the falling speed of the sheet. After the upper, first finger pair 51 has arrived in the region of lower edge 21.2, and the second, lower finger pair 51', not in engagement before, has been transported upward to the same extent by belts 52, fingers 51; 51' are brought back down from the existing lowering speed to the lesser initial speed, and drive unit 7 associated with deposition means 5 is shut down when the lower or second finger pair 51' is in the starting position. This sheet delivery and deposition cycle just described then repeats continuously until a desired sheet stack height or sheet count has been reached; the sheet stack height or sheet count can, for example, be determined in known fashion by means of the control unit, by counting the sheets detected by sensor 62. In an alternative embodiment (not shown) of the invention, only one finger pair 51 or one finger 51 is arranged on each of the two belts 52. Said single finger pair 51 is conveyed back into its upper starting or initial position, after a fed-in sheet S has been lowered, deposited, and aligned, at a lifting speed which is considerably greater (e.g. more than twice as great) as the lowering speed, so as to bring said finger pair back into the initial position at the proper time before the next sheet Sn is fed in by sheet infeed roller pair 42, 43. In addition, belt idler pulleys 55 are arranged on a separate shaft which lies between sheet infeed drive roller 42 and upper edge 21.1 of sheet stop 21. In a further alternative embodiment (not shown) of the invention, conveying means 50 of deposition means 5 have either only one centeredly arranged belt 52 or in fact three belts instead of two belts. The single belt 52 or the three belts 52 each contain either one finger 51, or two fingers 51 and 51'. In this context, sheet guide tongues 80, guide panel 53, and the number of recesses 22 in the rear wall, or the number of sheet stop struts 21, are adapted to the respective embodiments. Sheet guide means 8 or their tongues 80 are, in this context, controlled as to position by means of a cam wheel driven by belt drive unit 7; resilient tongues 80 can be pivoted with their front ends into an upper release position while a sheet S is being fed in, and into a lower sheet pressure position on fingers 51 or 51' after sheet S has been fed in. Also in this embodiment that is not shown, the two roller pairs 40, 41; 42, 43 of sheet delivery means are replaced by a single belt drive having a sheet transport belt (e.g. a vacuum transport belt). In a third embodiment (not shown) of the invention, deposition means 5 are arranged on a front (in sheet delivery direction X) end wall 23, configured as a sheet stop, of stack container 2. Fingers 51, 51' point away from the sheet delivery direction X, and are continuously moved counterclockwise to lower a fed-in sheet S. When viewed in sheet delivery direction X, sheet stack container 2 and the sheet stop are arranged with a downward inclination or tilt. In order to guarantee conditions which are as identical as possible when lowering, depositing, and aligning sheets S onto sheet deposition surface 20 and sheet stack ST of varying heights, stack container 2 is movable vertically up and down with its sheet deposition surface 20 as a function of the sheet stack height, i.e. can be lowered (not shown) as the sheet stack becomes higher. Reference signs S Delivered/fed-in sheet (to sheet stack) S' Deposited sheet Sn Further delivered sheet Sx Front end region of delivered sheet Sy Rear end region of delivered sheet ST Sheet stack STx Front end region of sheet stack Sty Rear end region of sheet stack X Sheet delivery direction Y Sheet return direction Z Sheet stacking direction 1 Device for delivering, depositing and aligning 2 Stack container for collating sheets 3 Apparatus (copier) 4 Sheet delivery means 5 Sheet deposition means 6 Drive unit for sheet infeed pair (sheet delivery means) 7 Drive unit for sheet deposition means 8 Sheet guide means for delivered/fed-in sheet 20 Sheet deposition surface (stack container) 21 Sheet stop/sheet stop struts on rear wall of stack container 21.1 Upper edge of sheet stop (stack container) 21.2 Lower edge of sheet stop (stack container) 22 Recess(es) on rear wall/sheet stop (stack container) 23 Front wall of stack container 40 Drive roller of sheet delivery roller pair (sheet delivery means) 41 Pressure roller of sheet delivery roller pair (sheet delivery means) 42 Drive roller of sheet infeed roller pair (sheet delivery means) 43 Pressure roller of sheet infeed roller pair (sheet delivery means) 44 Drive shaft of drive roller of sheet infeed roller pair 50 Conveying means (sheet deposition means) 51 First/upper resilient finger/finger pair (conveying means) 51' Second/lower resilient finger/finger pair (conveying means) 51.1 Lower friction surface on finger 51.2 Upper friction surface on finger 52 Belt/belts for fingers 53 Guide panel for fingers (belt drive pulley and sheet infeed drive roller) 54 Drive pulley for belt/belts (conveying means) 55 Idler pulley for belt/belts (conveying means) 56 Drive shaft of drive pulley for belt/belts (conveying means) 60 Drive motor of drive unit for sheet delivery means 61 Drive belt for sheet infeed roller pair 62 Sensor preceding sheet delivery roller pair 70 Drive motor of drive unit for conveying means 80 Sheet guide tongue (sheet guide means)

Claims: Device for delivering, depositing and aligning sheets (S) in a stack container (2) of an apparatus (3) by means of sheet delivery means (4) and sheet deposition means (5), said sheets are aligned against a sheet stop (21) of said stack container lying at right angles to the sheet deliver direction characterized in that said sheet deposition means (5) includes a plurality of sheet alignment means and sheet hold down means (51, 51'), said sheet alignment means and said sheet hold down means are driven in a circulating fashion to control sheets delivered by said delivery means (4) for deposit in said stack container (2), in a non-inverted orientation and held in place on the sheet stack (ST), said plurality of sheet alignment means and sheet hold down means of said sheet deposition means are separately controllable for selective guided lowering and deposition of delivered sheets. Device (1) as defined in Claim 1, characterized in that the sheet deposition means (5) can be operated by means of a drive unit (7) controllable separately from the sheet delivery means (4); and the sheet deposition means (5) can be moved at a lowering speed which is the same as or slightly less than the falling speed of the delivered sheet (S). Device (1) as defined in Claim 2, characterized in that the sheet deposition means (5) are controllable as to their lowering speed as a function of the sheet type. Device (1) as defined in Claim 2, characterized in that the sheet deposition means (5) can be returned at a lifting speed which is the same as or greater than the lowering speed. Device (1) as defined in Claim 1 or 4, characterized in that the sheet deposition means (5) can be operated in discontinuously circulating fashion, but in synchronism with sheet delivery. Device (1) as defined in Claim 1 or 5, characterized in that the sheet deposition means (5) are arranged, on the one hand in the region of a sheet infeed roller pair (42, 43) of sheet delivery means (4), and on the other hand in the region of a rear wall (21), lying transversely to the sheet delivery direction (X) and configured as a sheet stop (21), of the collection container (2), such that the sheet deposition means (5) are movable in the stacking direction (Z) directly along the sheet stop (21). Device (1) as defined in Claim 1 or 6, characterized in that the sheet deposition means (5) have conveying means (50) having at least one resilient finger (51, 51') for carrying a delivered sheet (S), such that by means of the finger(s) (51, 51') during its/their lowering movement, a delivered sheet (S) is held at one of its end regions (Sy) and can be lowered and deposited onto the sheet stack (ST) in linear, uniform, and completely guided fashion. Device (1) as defined in Claim 7, characterized in that the resilient finger(s) (51, 51') is/are arranged in a perpendicularly projecting alignment on one or more circulating belts (52) of the conveying means (50) running parallel and extending in the stacking direction (Z) of the sheets; and each finger (51, 51) has at its fingertip a lower (51.1) and an upper (51.2) surface region with an elevated coefficient of friction. Device (1) as defined in Claim 7 or 8, characterized in that each resilient finger (51, 51') is additionally configured as an alignment means and hold-down means; and each resilient finger (51) can be lowered by means of the conveying means (50) onto an outermost end region (Sty) of the sheet stack (ST), and can be moved downward past its end face in such a way that on the one hand a delivered sheet (S), guided by means of the finger(s) (51, 51'), can be lowered/deposited onto the sheet stack (ST) and moved so as to align against the sheet stop (21), and on the other hand the previously deposited sheet (S') can be held down by the finger(s) (51) on the sheet stack (ST) and can be moved so as to align against the sheet stop (21). Device (1) as defined in Claim 1, 6, or 9, characterized in that the sheet stop (21) is arranged with its upper edge (21.1) in the stacking direction (Z) arranged tilted against the sheet delivery direction (X) and toward the sheet deposition means (5), such that the sheet deposition means (5) can be moved in the stacking direction (Z) at an acute angle along the sheet stop (21), and the stack container (2) is inclined downward with an end of its sheet deposition surface (20) pointing away from the sheet delivery direction (X). Device (1) as defined in Claim 1 or 7, characterized in that the sheet deposition means (5) have, in the region of the sheet delivery means (4), sheet guide means (8) or controllable sheet pressure means (8) which coact with the sheet deposition means (5) as the sheet begins to be lowered. Device (1) as defined in one of Claims 1 to 11, characterized in that the sheets (S, S') are configured as paper, board, or film; and the apparatus (3) is configured as a copier, printer, printing press, or sheet sorter.

Inventors: ALLMENDINGER FRANZ, ALLMENDINGER, FRANZ
Applicants: NEXPRESS SOLUTIONS LLC
Application year: 1999
Main classification: B65H29
IPC codes: B65H29, B65H31