A device for depositing sheets on supports situated one above the other

Abstract: A device for selective deposition of sheets on supports (8; 9) situated one above the other, each such support being movable into a deposition position in which a sheet deposition means (10) disposed at a fixed place can deposit a sheet on the associated support or on a stack of sheets (23) situated thereon. A support (8) situated at a higher level is movable between its deposition position in which said support or the top edge of a stack of sheets disposed thereon is at the height of the sheet deposition means (10), and a parking position (A) which is at a higher level than the sheet deposition means (10). The next lower support (9) is movable between its deposition position in which said support or the top edge of a stack of sheets (23) disposed thereon is at the height of the sheet deposition means (10), and a parking position (B) in which the top edge of a stack of sheets (23) to be formed thereon is at a lower level than the next higher support (8) when the latter is in the deposition position with a stack of sheets thereon.

Description: The invention relates to a device for depositing sheets on supports situated one above the other, comprising positioning means for selectively placing the supports in a deposition position and a sheet deposition means for depositing a sheet on a support disposed in the deposition position or on a stack of sheets disposed on said support. A device of this kind is known from the Research Disclosure Bulletin of April 1983, page 146, No. 22802. This describes a device in which the supports, at fixed distances one above the other, are disposed in a casing movable up and down to enable each support to be moved into a deposition position. A device of this kind is used in a copying machine marketed by Océ-van der Grinten N.V. under the name Océ-2500. In this known application, the supports form a number of deposition bins in each of which sets of copy sheets made in the copying machine can be deposited on one another. When the casing does not contain any sheets, the empty casing is brought with its bottom support level with a pair of delivery rollers acting as sheet deposition means and the casing projects with the other supports above the pair of delivery rollers over a distance corresponding substantially to the total height of the casing. The casing moves down during the time when the deposition bins are being filled with sets of copy sheets. When the consecutive bins have been successively filled with sets of copy sheets, the casing has been moved down over a distance corresponding substantially to the total height of the casing. If there are following sets of copy sheets to be deposited, the casing is first emptied and then moved upwards until the bottom support is again level with the pair of delivery rollers. The deposition of sets of copy sheets can then be resumed. A sheet deposition device of this known type is attractive because of the common short distance that sheets only have to cover to reach each of the bins, thus the risk of any malfunction during the transport of copy sheets, being small. However, one objection to this known sheet deposition device is that considerable space is required to move the bin casing up and down, i.e. almost twice the volume of the casing. The object of the invention is to provide a device of the type referred to in the preamble which obviates this disadvantage. According to the invention, this object is attained in a device according to the preamble, in that a first support is movable into a position in which the distance to a next higher support is less than the maximum thickness of a stack of sheets to be formed on the first support. The effect of this is that the space required for moving the supports up and down is much smaller than twice the volume occupied by deposited sheets. When the first support is movable to just beneath the next higher second support this volume reduction comprises the volume of the maximum stack of sheets formable on the first support. Preferably, the maximum thickness of the stack of sheets formable on the first support is greater than the maximum thickness of the stack of sheets formable on the second support. The effect of this is that direct changeover from depositing sheets on a higher support to depositing them on a lower support requires little time since when the higher support moves upwards as is required for this changeover, over a distance corresponding to the thickness of the stack formed on the higher support, only this distance has to be traversed. Even if the number of supports is limited to two, deposition of sheets can be continued continuously without interruption when sheets deposited on one of the two supports are removed when deposition of sheets takes place on the other support. Other features and advantages of the invention will be explained with reference to the accompanying drawings wherein: Fig. 1 is a front elevation of a device according to the invention. Fig. 2 is a top plan view of the device shown in Fig. 1. Fig. 3 is a block schematic of a control system for the device shown in Figs. 1 and 2. Fig. 4 is a decision diagram for the operation of the device in a first mode, the selected tray mode. Fig. 5 is a decision diagram for the operation of the device in a second mode, the mixed mode, and Fig. 6 is a decision diagram for the operation of the device in a third mode, the continuous mode. The sheet deposition device 1 illustrated in Figs. 1 and 2 is situated next to the copy sheet delivery section 2 of a copying machine, e.g. a laser printer. The delivery part 2 projects above the copying part 3 of the copying machine and has a copy sheet delivery opening 6 at a side edge 4 which includes an angle of 90° with a free top surface 5 of the copying part 3. The sheet deposition device 1 comprises two sheet deposition trays 8 and 9 for depositing thereon copy sheets discharged from the copying machine and is situated in the space defined by the side edge 4 of the delivery part 2 and the top surface 5 of the copying part 3. The delivery part 2 is of the type represented in US patent 4 750 853 adapted to collect and staple sheets printed in the copying part 3 and delivering these collected sheets (or loose sheets) through the sheet delivery opening 6 by means of a pair of conveyor rollers 10 disposed at a fixed location. The sheet deposition device 1 is pivotally secured to the sheet delivery part 2 by means of a spindle 11 shown in Fig. 2, which extends vertically at the rear situated opposite the operating side of the copying machine. If the sheet deposition device 1 is pivoted away from the sheet delivery part 2, the sheet delivery opening 6 and the copying part 3 situated beneath the sheet deposition device 1 are accessible, e.g. for the removal of copy sheets jammed therein. The sheet deposition device 1 pivotally secured to the sheet delivery part 2 comprises a frame with parts 12 and 13 which, considered in the horizontal direction, form an L. Frame part 12, which carries the pivot spindle 11, is situated at the rear of the copying machine remote from the operating side and accommodates fixing and drive means for the sheet deposition trays 8 and 9. Frame part 13 is situated in front of the sheet deposition trays 8 and 9 at the side remote from the delivery opening 6 and accommodates positioning means 15 for positioning on the trays 8 and 9 sheets coming out of the copying machine. The fixing and drive means in the frame part 12 comprise a vertical column 16 to which a rack 17 and alignment guides 18 and 19 are secured. Two strips 21 and 22 are also secured in the frame part 12 and each has a U-shaped cross-section with recesses in the limbs of the U. The strips 21 and 22 have a function in the displacement and positioning of the trays 8 and 9 vertically as will be explained hereinafter in detail in connection with the description of the operation of the sheet deposition device. The mechanisms for guiding and displacing the trays 8 and 9 are substantially identical so that a description will solely be given of the mechanism intended for this purpose for the tray 8. In Fig. 1, the sheet deposition device 1 is shown in a position in which the bottom sheet deposition tray 9 is in a deposition position with a stack of sheets 23 on said tray, the top sheet deposition tray 8 being shown in a parking position denoted by A, in which position sheets coming out of the sheet delivery part 2 cannot be deposited on the tray 8. Sheet deposition tray 8 comprises a subframe with support arms 25 and 26 for said tray. Eight freely rotatable rollers 27 are secured to the support arms 25 and 26 and co-operate with alignment guides 18 and 19 for vertical guidance of the sheet deposition tray 8. Two of the rollers 27 are provided with collars which engage next to the associated alignment guide to enclose the tray frame in the lateral direction. A pinion 28 is also secured to the subframe of tray 8 and engages rack 17. Pinion 28 is coupled, via a self-locking wormwheel transmission, to a motor 29 also secured to the subframe of tray 8. Motor 29 is reversible. A unidirectional bearing is built into the pinion 28 so that the tray 8 can be manually raised. When the motor 29 is energised in the required direction of rotation, tray 8 is moved up or down along the alignment guides 18 and 19, as will be explained hereinafter in connection with the description of the operation of the deposition device. On the downward movement, the loading does not increase in excess of the weight of the tray with its drive and the stack thereon. This loading is less than a maximum permissible loading of 150 N. Thus the operator cannot reach between the trays with his hand pinched between the trays or between the bottom tray 9 and the top surface 5. To avoid the risk of pinching on the upward movement of tray 8, the same is also provided with a safety feature which prevents this tray from being driven to a position above the parking position A. Motor 29 for driving tray 8 via pinion 28 and the corresponding motor 31 for driving tray 9 via pinion 30 are disposed next to one another, motor 29 for tray 8 extending from said tray downwards and motor 31 for tray 9 extending from said tray upwards. Thus, on the one hand, the motors 29 and 31 do not obstruct one another when the trays 8 and 9 are close together while on the other hand the motors 29 and 31 do not project above or below the deposition device 1 respectively when the trays 8 and 9 are far apart. Guide bushes 32 and 33 respectively are secured to the support arms 25 and 26 as shown more particularly in Fig. 2. Guide bushes 32 and 33 respectively cooperate with guide rods 34 and 35 respectively secured to the tray 8. A spindle 36 is also secured to the tray 8 and can co-operate with link 38. Link 38, and the corresponding link 37 for tray 9, extend next to the support arms 26 and 25 respectively as far as the frame part 12, where they each have a vertical slot co-operating with a pin 39 eccentrically secured or, the shaft of a drive motor 40 and 41 respectively. On energisation of motor 40 or the associated motor 41 for tray 9, the tray can thus be moved horizontally between two end positions in which the tray is displaced relatively to the delivery opening 6 transversely over a short distance, e.g. 25 mm. The bottom sheet deposition tray 9 is also provided with a manually operated locking means 42 by which the link 37 can be released from the spindle 36. Tray 9 can then be manually pulled farther forward as shown in Fig. 2 in broken lines, to facilitate the removal of sheets from the tray. In order further to facilitate removal, both trays have a recess 43 to enable a stack of sheets to be easily taken hold of and removed. For the easy removal of a large stack of sheets, extra recesses 44 and 45 are formed in tray 9 for manual support of the side edges of this thick stack of sheets. The covering surface of frame part 13 situated opposite the delivery opening 6 has vertical ridges 46 which act as an abutment for the sheets delivered by the pair of rollers 10. As a result of the small contact surface between the deposited sheets and the ridges 46, the stack that is formed experiences little obstruction from transverse movements of trays 8 and 9. The risk that a stack that has been formed may shift with respect to its support can further be reduced by forming the ridges as rollers which are freely rotatable about a vertical axis and which, on transverse movement of a support with the stack thereon, participate in the movement. The positioning means 15 disposed in frame part 13 comprise a positioning shoe 47 disposed level with the delivery opening 6. Positioning shoe 47 is movable between a working position shown in solid line in Fig. 1 and a parking position shown in broken line. In the working position shown in solid line, a horizontal surface 48 of the shoe presses, solely by its own weight, on the stack 23 and an adjoining surface 49 sloping up at an angle of 45° acts as a guide for sheets delivered by transport rollers 10, to guide them to the stack 23. In the parking position shown in broken line, the positioning shoe 47 is situated completely at the side of the ridges 46 remote from the delivery opening 6. Positioning shoe 47 is vertically movable over a small rod 50 between a position in which the shoe 47 rests on a collar 51 formed on the rod and a higher position. Guide rod 50 is rotatable about a pivot 52 and is held in the broken-line parking position by a spring (not shown), in which position deposition tray 8 particularly can move along the positioning shoe. By means of an electromagnet 53 the positioning shoe 47 can be set to the solid-line working position, in which position the positioning shoe is lifted from collar 51 by the tray in the deposition position, or by the stack situated thereon. On the side of the deposition trays remote from the positioning shoe 47 a tapper 55 is provided beneath the pair of rollers 10, which tapper is movable by means of an electromagnet 57 between a solid-line parking position in which the tapper 55, as considered in the delivery direction, is further away from the ridges 46 than the dimension of sheets to be stacked in that direction, and a broken-line position in which the tapper 55 is at a distance from the ridges 46 equal to the dimension of the sheet in the delivery direction. The position of the tapper 55 in the broken-line position can be adjusted to the dimension of the sheets in the delivery direction by adjustment of a stop 56 for the tapper 55. During each deposition cycle, the positioning shoe 47 is first set into the solid-line working position by electromagnet 53. During the delivery of sheets by the pair of rollers 10 which takes place thereupon, the sheets are guided by guide surface 49 of the positioning shoe to the stack where they are pushed under surface 48 of the positioning shoe, in order to brake the sheets before they abut the ridges 46. After the delivery movement, tapper 55 is pressed by electromagnet 57 against the stack twice in short succession in order to press the deposited sheets straight against the abutment ridges 46. At the end of each deposition cycle, the tray on which deposition took place is moved transversely over a short distance by energisation of motors 40 and 41 respectively, in order thus to enable the following sheets to be deposited in an offset position with respect to the previously deposited sheets, as indicated in Fig. 2. The deposition device illustrated is adapted to receive a stack of about 1700 sheets of a weight of 80 g/m² on tray 9 and a stack of about 500 sheets of a weight of 80 g/m² on tray 8. Tray 8 is specially adapted to receive stapled sheets. Owing to the fact that corner-stapled sheets result in an oblique stack being formed on deposition, a stack of 500 sheets is considered the maximum feasible. For that reason, the number of sheets that can be deposited on tray 9 when the machine is set to stapling is also limited to 500 sheets as will be explained hereinafter. The deposition device 1 is of use particularly for copying machines, such as laser printers, for large runs of short copy jobs, e.g. for direct mail, and for making a single copy of a long copying job, e.g. the printing of computer forms. The deposition device 1 shown in Figs. 1 and 2 is provided with a control system 60 shown in Fig. 3. The control system 60 co-operates with sensors disposed in the device 1: a reflection sensor 61 disposed at the deposition height of the tray in the working position, said sensor delivering a signal when the tray in the working position or a stack of sheets thereon falls to below the sensor, a sensor 62 disposed a short distance beneath sensor 61 and also delivering a signal when the stack formed falls to below said sensor 62, mechanical sensors 63 and 84 respectively disposed in trays 8 and 9 and delivering a signal when there are no sheets on the associated tray, sensors 65 and 66 secured to tray 8 and co-operating with the limbs of strips 22 and delivering a signal on sensing the start and the end of recesses formed in the limbs of strip 22, sensors 67 and 68 secured to tray 9 and co-operating with the limbs of strip 21 and delivering a signal at the start and end of recesses formed in the limbs of strip 21, and a sensor 69 also secured to tray 9 and co-operating with one of the limbs of strip 22 and delivering a signal at the start and/or end of a recess formed in strip 22. Sensors 63 and 64 operate to detect the associated trays when empty. Sensors 61 and 62 act to maintain the deposition level of the tray in the deposition position. To this end, to lower the associated tray, the motor is so controlled that the deposition level remains between the sensors 61 and 62. Together with the signalling by sensors 66 and 67 to show that the associated tray has reached the lowest position, sensor 61 also acts as an almost-full detector and sensor 62 operates also as a full-detector. Sensor 65 reacts when tray 8 is at the deposition level. Sensor 68 reacts when tray 9 is at the deposition level and when tray 9 reaches parking position B. Sensor 66 reacts when tray 8 is at a distance below the deposition level corresponding to 500 sheets and when tray 8 reaches its parking position A. Sensor 67 reacts when tray 9 is at a distance below the deposition level equal to 1700 sheets. The operation of the device will now be explained also by reference to the block schematic shown in Fig. 3, of a control device 60 operating in dependence on the mode (M1, M2 or M3) to which the control system 60 is set and by reference to decision diagrams of those modes as shown in Figs. 4, 5 and 6. A signal 70 representing the setting of the sheet delivery part 2 to stapling can also be added to the control system. In mode M1, the selected tray mode, of which Fig. 4 shows the decision diagram, tray 8 or 9 can be selected for use. Deposition can take place only on the selected tray. If the associated tray is full, the copying process stops as does also the deposition of the following copy sheets. After the sheets have been removed from the associated tray, the copying process can be re-started and deposition resumed. The tray-full signal is dependent upon the selected tray and the presence of a signal 70. In the absence of signal 70, full-detection for tray 9 takes place at 1700 sheets and for tray 8 at 500 sheets. In the presence of signal 70, full-detection takes place for both trays at 500 sheets. In mode M2, the mixed mode, the decision diagram of which is shown in Fig.5, stapled sheets - i.e. in the presence of signal 70 - are automatically deposited on tray 8 and unstapled sheets - i.e. in the absence of signal 70 - are automatically deposited on tray 9. On the changeover from stapling to non-stapling, or vice versa, the other tray is automatically placed in the deposition position. The copying process and hence delivery and deposition of sheets stops when it is no longer possible to deposit the following sheets, or because the following sheets have to be stapled and the tray 8 is full, or because the following sheets are to be left unstapled and the tray 9 is full. In mode M3, the continuous mode, the decision diagram of which is shown in Fig. 6, deposition of sheets starts with an empty tray 9 in the deposition position. When the maximum number of sheets has been deposited on tray 9 (about 1700 sheets with the non-stapling setting and 500 sheets with the stapling setting), tray 9 is automatically moved further down into the parking position B and tray 8, provided it is empty, is automatically lowered from its parking position A to the deposition position and deposition is continued on tray 8. With normal copying speeds, it takes about 10 minutes before tray 8 is full. If in that period all the sheets have been removed from tray 9, then when tray 8 is full deposition will be continued on tray 9. If not all the sheets have been removed then sheet deposition stops. This prevents any disturbance to the sequence in which the sheets are deposited. Thus the copying process can be continued uninterruptedly without it being necessary to break it off to remove sheets from the deposition device 1.

Claims: A device for depositing sheets on supports (8, 9) situated one above the other, comprising positioning means for selectively placing the supports (8, 9) in a deposition position and a sheet deposition means (10) for depositing a sheet on a support (8 or 9) disposed in the deposition position or on a stack of sheets disposed on said support, characterised in that a first support (9) is movable into a position in which the distance to a next higher support (8) is less than the maximum thickness of a stack of sheets (23) to be formed on the first support (9). A device according to claim 1, characterised in that the maximum thickness of the stack of sheets (23) to be formed on the first support is greater than the maximum thickness of the stack of sheets to be formed on the next higher support. A device according to claim 1 or 2, characterised in that the number of supports is two. A device according to any one of the preceding claims, characterised in that the first support (9) is movable between a deposition position in which the distance between the first support (9) and the sheet deposition means (10) disposed at a fixed place corresponds to the thickness of the stack of sheets to be formed on the first support (9) and a parking position (B) in which the first support (9) is situated at a distance beneath the sheet deposition means (10) corresponding to the sum of the maximum thicknesses of the stacks formable on the first support (9) and the next higher support (8) and in that the next higher support (8) is movable between a deposition position in which the distance between said support and the sheet deposition means (10) corresponds to the thickness of the stack of sheets to be formed on said support (8) and a parking position (A) in which said support (8) is situated at a distance above the sheet deposition means (10) corresponding to the thickness of said support (8). A device according to claim 4, characterised in that control means (60) are provided which comprise first detection means (61, 67, 69) for generating a first detection signal in the presence of a stack of sheets of maximum thickness when a support is in the deposition position, and in that the control means (60) place the associated support from the deposition position into its parking position (A; B) in response to said first detection signal. A device according to claim 5, characterised in that the control means (60) comprise second detection means (63; 64) for each support (8; 9) for generating a second detection signal in the absence of sheets on the associated support (8; 9) and in that the control means (60) place the associated support from its parking position (A; B) into the deposition position in response to said second detection signal. A device according to claim 6, characterised in that the control means (60) are adjustable by a first adjustment signal to a mode in which only the first support (9) can be moved into the deposition position and are adjustable by a second adjustment signal to a mode in which only the next higher support (8) is movable into the deposition position. A device according to claim 7, characterised in that the first adjustment signal corresponds to a first property of sheets to be deposited and the second adjustment signal corresponds to a second property, differing from the first, of the sheets to be deposited. A device according to any one of the preceding claims, characterised in that a sheet guide means (47) is disposed at the height of the sheet deposition means (10) and at the side of the supports (9, 8) remote from said means (10), said sheet guide means (47) being movable between an operative position in which the sheet guide means (47) extends above the support (9; 8) in the deposition position to guide a sheet to be deposited to its deposition place on said support (9; 8) and an inoperative position in which the sheet guide means (47) is situated completely outside the path of movement of the supports (9; 8). A device according to claim 7, characterised in that a sheet pressure application means (55) is disposed on the side of the supports where the sheet deposition means (10) is situated and is movable between a position in which the sheet pressure application means (55) presses a deposited sheet in the direction of the sheet guide means (47) against an abutment (46) which extends along the supports (8, 9) and a withdrawn position in which the sheet pressure application means (55) is free from deposited sheets. A device according to any one of the preceding claims, characterised in that each support (8; 9) is provided with a gearwheel (28; 30) drivable by a motor (29; 31), said gearwheels (28, 30) co-operating with a rack (17) which extends next to the supports and in the vertical direction of movement thereof.

Inventors: SAMPERS PETER JOHANNES ANDREAS, VAN OPSTAL FRANCISCUS CORNELIU, SAMPERS, PETER, JOHANNES, ANDREAS, VAN OPSTAL, FRANCISCUS, CORNELIUS, PETRUS
Applicants: OCE NEDERLAND BV, OCE-NEDERLAND B.V.
Application year: 1992
Main classification: B65H31
IPC codes: B65H31, B65H39