Control method for sorter with stapler

Abstract: A method of controlling a sheet sorter (1) wherein the sheet sorter includes a plurality of bins (B) for accommodating sheets, the bins being arranged in a vertical direction, a first sheet discharging device for discharging sheets not to be sorted, second sheet discharging device, disposed with a vertical interval from the first sheet discharging device, for discharging sheets to be sorted, bin moving device for moving substantially vertically the bins and stapler device (45) for stapling the sheets, the method includes providing the stapler device (45) adjacent to the second sheet discharging device; accommodating the sheets on the plurality of bins (B) by sequentially opposing the bins to the second sheet discharging device, and stapling the sheets on the bins by the stapler (45), when a sorting mode is selected; discharging the sheets by the first discharging device and accommodating them on a non-sort bin opposed to the first discharging device (11) when a non-­ sorting mode is selected, and moving the non-sort bin to a neighborhood of the second discharging device (12) where the sheets thereon are stapled by the stapler device (45)

Description: The present invention relates to a sheet sorter coupled with an image forming apparatus such as a copying machine and printer to sort and stack sheets such as copies and prints discharged from the image forming apparatus, more particularly to a control method for a sheet sorter provided with a plurality of movable bins for receiving the sheets and provided with a stapler at a sheet discharging portion to staple the sheets. The document JP-A-60 088 969 discloses a method for controlling a sheet sorter which includes a plurality of vertically arranged bins for accommodating sheets, a first sheet discharging means for discharging sheets not to be sorted, a second sheet discharging means disposed at a vertical interval from the first sheet discharging means, for discharging sheets to be sorted, and bin moving means for moving the bins substantially vertically. According to this method, the sheets are accommodated on the plurality of bins by sequentially opposing the bins to the second discharging means when a sorting mode is selected, and the sheets are discharged by the first discharging means and accommodated on a non-sort bin opposed to the first discharging means when a non-sorting mode is selected. Also, a limitless sorter is known in which the sheets can be sorted and accommodated without limitation by the number of bins, which will hereinafter be called "limitless sorter", and in which set of sheets are stapled in the respective bins. For example, U.S. Patent No. 3,884,408 discloses a horizontal limitless sorter of a stationary bin type in which a carriage for carrying a stapler is movable to the respective bins, and the stapler is rotated away from the carriage to staple a stack of sheets. Further, the Japanese Laid-Open Patent Application No. 220053/1983 discloses a limitless sorter in which a stapler block moves substantially vertically, expands the space between adjacent bins and inserts a stapling head into the space to staple the stack of sheets. Furthermore, the U.S. Patent No. 4,295,733 discloses a limitless sorter in which a set of sheets is gripped by a gripper, and is transported to a stapler by which it is stapled. In the conventional sorters incorporating a stapler, the stapler is generally disposed adjacent the discharging portion for discharging the sheets in the sort mode. Therefore, the stapling operation in the non-sort mode is not considered. SUMMARY OF THE INVENTION Accordingly, it is a principal object of the present invention to provide a control method for a sorter with a stapler, in which sheets can be stapled in the sort-mode and in the non-sort mode. This object is achieved by the features indicated in the independent claim 1. According to the teaching of this claim, there is provided a method for controlling a sheet sorter which includes a plurality of bins for accommodating sheets, the bins being arranged in a vertical direction, a first sheet discharging means for discharging sheets not to be sorted, a second sheet discharging means disposed at a vertical interval from the first sheet discharging means, for discharging sheets to be sorted, and bin moving means for moving the bins substantially vertically. According to this method, the sheets are accommodated on the plurality of bins by sequentially opposing the bins to the second discharging means when a sorting mode is selected, and the sheets are discharged by the first discharging means and accommodated on a non-sort bin opposed to the first discharging means when a non-sorting mode is selected. According to the invention, this method further comprises the steps of stapling the sheets on the bins by a stapling means provided adjacent to the second sheet discharging means when the sorting mode is selected, and moving the non-sort bin to a neighborhood of the second discharging means where the sheets thereon are stapled by the stapling means when the non-sorting mode is selected. Therefore, according to the invention, even when the non-sort mode is selected, the stapling operation can be performed smoothly. Advantageously developed embodiments of the invention are subject matter of the dependent claims 2 to 4 In this connection, attention is drawn to the copending applications 88 110.967.2, 88 112 386.3 and 88 112 388.9. These and other features and advantages of the present invention will become more apparent upon a consideration of the following description of the preferred embodiments of the present invention taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a side view of a sorter according to an embodiment of the present invention. Figure 2 is a perspective view thereof. Figure 3 is a perspective view of a bin unit. Figure 4 is a top plan view illustrating the engagement between a lead cam and a trunnion. Figure 5A is a side view illustrating the movement of the bins by the lead cam as seen in the direction indicated by an arrow V (a) in Figure 6. Figure 5B is a side view illustrating the movement of the bins by another lead cam, as seen in the direction indicated by an arrow V (b) in Figure 6. Figure 5C is a schematic simplified view of Figure 5A. Figure 5D is a schematic simplified view of Figure 5B. Figure 6 is a top plan view illustrating a driving mechanism for the lead cams. Figure 7 is a side view illustrating the bin movement by the same configuration of the lead cams, as seen in the direction indicated by an arrow VII (a) in Figure 8. Figure 8 is a top plan view illustrating a driving mechanism for the lead cams. Figure 9 is a side view of an image forming unit illustrating a non-sort stapler. Figure 10 is a side view of a sorter illustrating a bin position when the stapling operation is performed. Figure 11 is a block diagram illustrating a control operation of the sorter. Figure 12 is a flow chart illustrating an operation of the image forming unit. Figure 13 is a perspective view of a bin unit illustrating details of an alignment means. Figure 14 is a side view of a sorter according to another embodiment of the present invention. Figure 15 is a side view illustrating the expansion of the spaces between adjacent bins by a lead cam. Figure 16 is a perspective view illustrating the arrangement of an electric stapler. Figure 17 is a top plan view illustrating operations of an electric stapler and an aligning rod. Figure 18 is a top plan view illustrating an alignment reference in this embodiment. Figure 19 is a side view of a sorter according to a further embodiment of the present invention, illustrating expanding means. Figure 20 is a side view of expanding means according to a further embodiment of the present invention. Figure 21 is a side view of a lead cam according to a further embodiment of the present invention. Figure 22 is a top plan view of another example of a bin according to the present invention. Figure 23 is a sectional view taken along the line B-B of Figure 22. Figure 24 is a top plan view of a bin illustrating a sheet aligning operation. Figures 25 - 28 are top plan views and a sectional view of bins illustrating examples of a slot therein. Figure 29 is a top plan view of a sorter according to a further embodiment of the present invention, in which a stapler and a sheet detecting means are illustrated. Figure 30 is a side view of the apparatus of Figure 29. Figure 31 is a perspective view of the apparatus of Figure 29. Figure 32 is a perspective view of a post processor provided with the stapler shown in Figures 29 - 31. Figure 33 is a top plan view of an apparatus according to a further embodiment of the present invention. Figure 34A and 34B are side views illustrating sheet detecting means according to a further embodiment of the present invention. Figure 35 is a side view of a post processor particularly illustrating details of a mechanism for moving the stapler. Figure 36 is a sectional view taken along the line Y-Y of Figure 35. Figures 37A, 37B, 38 and 39 illustrate other examples of a mechanism for confining the curling of a sheet. Figure 40 is a perspective view of an apparatus according to a further embodiment of the present invention, in which a reference for positioning the sheet and the automatic stapler are shown. Figure 41 is a plan view of the apparatus illustrating sheet alignment and stapler positioning. Figure 42 is a perspective view of the apparatus illustrating a frame guide and an automatic stapler. Figure 43 is a plan view illustrating sheet alignment and stapler positioning in the apparatus of Figure 42. DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to Figures 1 and 2, there is shown a sorter according to an embodiment of the present invention. As shown in these Figures, the sorter 1 comprises a main assembly 6 including a couple of side plates 3, a base 5 and a cover 4. The sorter further comprises a bin unit 9 having a plurality of bins B and is movable substantially vertically along guide rails 7 mounted on the respective side plates 3. The main assembly 6 of the sorter 1 is provided with a sheet inlet 10 for receiving sheets from a copying machine or the like, and a first sheet passage 11 is formed extending from the sheet inlet 10 toward the bin unit 9. A second sheet passage 12 is formed branching out from the first sheet passage 11. Downstream of the first sheet passage 11 with respect to the movement direction of the sheet, an upper discharging roller couple 13 is disposed to discharge the sheets not to be sorted. Downstream of the second sheet passage 12, a roller discharging roller couple 15 is disposed to discharge the sheets to be sorted. A receiving roller couple 16 and a deflector 17 are provided at the branch between the first and second sheet passages 11 and 12. The deflector 17 is selectively displaceable to direct the sheet discharged by the upper discharging roller couple 13 toward the bin B located at the first sheet passage 11, or to direct the sheet discharged by the lower discharging couple 15 to the bin B located at the second sheet passage 12. The bin unit 9 includes a bin supporting frame 19 having vertical portions 19a and a bottom portion 19b (Fig. 13). The bin supporting frame 19 has a bin slider 20 mounted thereto at an end thereof, and the bin supporting frame 19 and the bin slider 20 are securedly fixed to each other by a bin cover 21. As shown in Figures 2 and 3, a reference member 22 for the alignment of the sheets is extended between the bin cover 21 and the bottom portion of the bin supporting frame 19, and is fixed to the bin cover 21. A swingable aligning rod 25 is extended through cut-away portions 23 formed in all of the bins B. The sheets received by the bins B are abutted to the reference member 22 by the swinging movement of the aligning rod 25 to align the sheets. Each of the bins B accommodated in the bin unit 9 is movably supported in comb-like channels of the bin slider 20 at an end thereof, and, at both sides at the base side thereof, it has pins 26 fixed thereto, as shown in Figure 4. Each pin 26 penetrates through a slit 27 formed in the bin supporting frame 19. To each pin 26 penetrated through the slit 27, a trunnion 30 is rotatably mounted by a cushion O-ring 29. The trunnions 30 of the bins B are stacked in the guide rail 7. The bottommost trunnion 30 is contacted to a lower guide roller 31 rotatably supported on the bin frame 19. The topmost trunnion 30 is contacted to an upper guide roller 32 rotatably supported on the bin supporting frame 19, so that each of the bins B is supported in the bin unit 9 with intervals between adjacent bins equal to the diameter of the trunnions 30. As shown in Figure 1, the upper guide roller 32 and the lower guide roller 31 are engaged with the guide rail 7, so that the bin unit 9 is movable substantially vertically. A spring 35 is stretched between a member 33 mounted to the bin supporting frame 19 of the bin unit 9, and a side plate 3 of the main assembly 6 of the sorter to normally urge the bin unit 9 upwardly. On each of the side plates 3, a cam shaft holder 36 is mounted at a position corresponding to the above described lower discharging roller couple 15, as shown in Figure 1 and 2. Between the cam shaft holder 36 and the base 5, a lead cam shaft 39 is rotatably mounted by means of a bearing 37. Above each of the lead cam shafts 39, lead cams 40 and 40' each having a helical cam surface are fixedly mounted. At the lower end of each lead cam shaft 39, a sprocket 41 is fixedly mounted, between which and a shift motor 42 a chain 43 is trained, so that the lead cams 40 and 40' are selectively rotated in a forward or a backward direction by selectively rotating the shift motor 42 in a forward or a backward rotation. The lead cams 40 and 40' are disposed faced to the lower discharge couple 15 disposed substantially at the center of the main assembly 6 of the sorter, and function to carry on their helical cam surfaces the trunnions 30 of a bin B moving toward the position faced to the lower discharging roller couple 15, to move it along the guide rail 7 in the vertical direction. By this, at a position faced to the lower discharging roller couple 15, an expanded space X which is larger than the intervals between other adjacent bins B is provided. On the other hand, the guide rail 7 formed in each of the side plates 3 has a configuration as shown in Figures 1, 5A and 5B, that is, it generally extends from the bottom to the top, and is bent away from the lower discharging roller couple 15 at a position faced to the lead cams 40 and 40'. When the trunnion 30 is moved along the guide rail 7, the bin Bb, for example, is guided along the lower portion 7b of the guide rail 7 to a position adjacent to the lower discharging roller couple 15, and receives the sheet P discharged from the lower discharge roller couple 15 without the trailing edge portion of the sheet P remaining on the stopper B'. After it has received the sheet, it is moved upwardly along the rail 7 (toward the upper portion 7a of the rail), avoiding the interference with the discharging roller couple 15. Therefore, the sheet P accommodated thereon is not interfered with the lower discharging roller couple 15. As described above, according to this embodiment of the present invention, the guiding means is constructed such that either of the trunnion not moved by the helical cam means and the trunnion moved by the helical cam means is shifted with respect to the other of them downwardly with respect to sheet discharge direction. Therefore, when the bin receives the sheet, it is close to the discharging means, whereas, after it has received the sheet, it avoids the interference with the sheet discharging means by shifting downwardly, so that the sheet is prevented from being carried on the trailing edge stopper of the bin, or is prevented from jamming. In addition, a head of a stapler may be disposed at the shifting position, so that the head can be disposed without interference with the base portion of the bin, whereby the sheet sorter can easily be equipped with a stapler. The description will be made as to the construction of the lead cams 40 and 40'. The lead cams 40 and 40' are helical in different directions, as shown in Figures 5A and 5B. As shown in Figure 6, the lead cam 40 and the lead cam 40' disposed at lateral sides provide driving forces in different directions. Further, the cam configurations of the lead cams 40 and 40' are such as to provide two (upper and lower) expanded portions X, simultaneously. The sheet being discharged through the lower discharging roller couple 15 is discharged to and is accommodated by the bin B faced to the lower discharging roller couple 15 through the upper expanded space X. Since the expanded spaces are simultaneously formed at two portions, the electric stapler unit 45 can be inserted for the bin B without the head 45a and the anvil 45b thereof unnecessarily interfering with the sheet (Figure 1). It has been found that, if the trunnions at both sides 30 and 30 are driven by lead cams 40 and 40' which have the same configuration and which are rotated in the same rotational direction, unlike the present invention, problems arise. Figure 8 shows a relationship between the left side lead cam 40 and the trunnion 30 driven by the lead cam 40. The bin Bb placed at the position facing the lower discharging roller couple 15 and the trunnion 30b, as shown in Figure 7, are moved by the lead cam 40 rotating in the direction of an arrow A from the position facing the lower discharging roller couple 15 to the position of the trunnion 30a of the bin Ba shown in this Figure as an upper adjacent bin. During this movement, a trunnion 30b receives from the lead cam 40 a force F (Figure 7) which is perpendicular to the inclination angle α of the helical cam surface of the lead cam 40, so that a large load is imposed on the trunnion 30b by the guide rail 7. Figure 8 also shows the relationships between the right hand lead cam 40' and the trunnion 30. Similarly, as shown in Figure 5B, the trunnion 30b is moved by the lead cam 40' rotated in the direction indicated by an arrow A, from a position opposed to the lower discharging roller couple 15 to the position of the trunnion 30a of the bin Ba shown as an upper bin in this Figure. During this movement, the force F applied by the lead cam 40' acts substantially along the bending direction of the guide rail 7 (Figure 5D), so that the load applied by the guide rail 7 is reduced. As a result, the trunnion 30 is moved very smoothly. As described, if the lead cam is rotated in the same rotational direction, one side of the bin B is smoothly moved, whereas the other side is moved with a large load, and, therefore, the movement of the bin B is not stabilized, so that noise is produced during movement of the bin, that the aligned sheets are disturbed on the bin B by vibration, and that the load of the shift motor 42 for driving the lead cams 40 and 40' is large. According to the above described embodiment of the present invention, problems like those stated above do not occur, since the lead cam 40 is rotated in the opposite rotational direction with respect to the lead cam 40', and the cam configuration is opposite to move the bins in the same direction at both of the lateral sides by the opposingly directed rotations of the lead cams 40 and 40'. Referring further to Figure 5B, the arrangement of the bins B will be described. The bin B is inclined downwardly toward the sheet inlet side, and is moved with the space between the bin B and the adjacent bin being increased and decreased in response to the vertical movement of the trunnion 30. As will be understood from this Figure, a gap A is formed between the leading edge (the sheet inlet side) of the bin placed at a sheet receiving position and that of the bin thereabove, as seen from a direction substantially perpendicular to a sheet supporting surface of the bin. A similar gap is formed between the bin at the sheet receiving position and the bin below it. A shaft for swinging movement of the stapler 45 extends substantially perpendicular to the sheet supporting surface of the bin, so that the stapler 45 rotates in a plane substantially perpendicular to the sheet in Figure 5B. By this rotation, the stapler head 45a of the stapler 45 approaches the top surface of the stack of sheets on the bin through a gap from a lateral side of the bin, and simultaneously, the anvil 45b approaches toward the bottom side of the stack of sheets through a space between the bins. Therefore, the space between adjacent bins is not required to be larger than the height of the stapler head 45a, and the stapling operation is possible with a relatively small space between the bins. In this embodiment, since the bin is further shifted substantially in the horizontal direction, a larger stapler head can be used. In operation, a sheet discharged from an image forming apparatus such as a copying apparatus is selectively guided by the deflector 17 which is displaced on the basis of the selection between the non-sort mode and the sort mode, from the inlet to the first sheet passage 11 or to the second sheet passage 12. When the non-sort mode is selected, the sheet is transported along the first sheet passage 11 and is discharged to the first bin B1 of the bin unit 9 by the upper discharging roller couple 13. When the sort mode is selected, the trunnion 30 is sequentially moved by the helical cams of the rotating lead cams 40 and 40', to provide an expanded space between bins B facing the lower discharging roller couple 15, which space is larger than the space between adjacent bins. During this movement, the moving trunnion 30 presses the upper guide roller 32 and the lower guide roller 31 to move the unit 9 as a whole. The sheet is discharged through the second sheet passage 12 by the lower discharge roller couple 15 to the first bin B1, and then discharged to the bin B2. As to the operation of the bin B moved adjacent to the lower discharging roller couple 15 when the sort mode is selected, the description will be made with the example of the bins Ba, Bb and Bc shown in Figures 5A and 5B. The bins Ba, Bb and Bc moved to the neighborhood of the lower discharging roller couple 15 are moved along the guide rail 7 with the trunnions 30a, 30b and 30c carried on the helical cam surface of the lead cam 40. Between the bins Ba, Bb and Bc, expanded spaces X and X which are larger than the intervals between the other adjacent bins are formed. The bin Bb having received the sheet discharged by the lower discharging roller couple 15 is moved to the position of the upper bin Ba, avoiding interference with the lower discharging roller couple 15, wherein the trunnion 30b is moved along the bent guide rail 7 by the lead cam 40 rotating in the direction indicated by an arrow D and by the lead cam 40' rotating in the direction indicated by an arrow A, by the rotation of the shift motor 42. The accommodating bin Bb moved close to the lower discharging roller couple 15 so as to assuredly receive the sheet P discharged by the lower discharging roller couple 15, is moved along the bent guide rail 7, so that it is not interfered with the lower discharging roller couple 15 after the sheet is accommodated. When the trunnion 30b is moved along the bent portion of the guide rail 7, the trunnion 30b receives the force F from each of the lead cams 40 and 40', which acts substantially along the bending direction of the guide rail 7 (Figures 5C and 5D). As a result, the bin B is efficiently moved, so that the load to the shift motor 42 is small. Also, the vibration of the bin B is small, and, therefore, the sheets aligned on the bin B are not disturbed, without production of noise. Referring to Figure 9, the description will be made as to the operation when the sheets are stapled in the non-sort mode operation. As shown in Figure 9, an image forming unit 1101 includes a copying apparatus 1102, an automatic original or document feeder 1103 disposed above the copying machine 1102 and a sheet sorter 1 disposed at one side of the copying machine 1102. Documents or originals P placed on an original stacking tray 1105 of the automatic document feeder 1103 are separated in order from the bottom, and are fed one by one through a passage 1107 onto the platen glass 1106 of the copying machine 1102. The original P is read by an optical system of the copying machine 1102. After it is read, it is returned from the platen glass 1106 to the topmost of the originals on the original stacking tray 1105. A sheet S having received an image of the original P is discharged to the sorter 1 depending on the number of copies to be taken, the selection of the sort mode or non-sort mode or the like. The sorter 1 is provided with a non-sort stapling controller for stapling non-sorted sheets. The controller is effective to control the above-described bin unit 9 and the electric stapler 45 when the sheets S are discharged onto the first bin B1 from the upper discharging roller couple 13 in the non-sort mode. When a selection is made to staple the sheets S on the first bin B1 by a preselected mode or after the sheets S are discharged onto the first bin B1, the controller causes the movement of the bin unit 9 so that the first bin B1 accommodating the sheets S is faced to the lower discharging roller couple 15, as shown in Figure 10, and causes the electric stapler 45 to perform the stapling operation to the sheets S on the first bin B1 now faced to the lower discharging roller couple 15. A reference numeral 1047 in Figure 9 designates a manual stapling switch. The operation will be described in conjunction with Figure 12. Originals P are placed on the automatic document feeder 1103 (F1). Then, the operator inputs into the copying machine 1102 a copying mode, a number to be copied, sort or non-sort mode selection and stapling or non-stapling mode selection (F2). When a copy start switch is actuated (F3), the copying machine discriminates the copying mode (a simplex copy, for example) and the sorter 1 discriminates whether the sort mode or non-sort mode is selected (F4). When the non-sort mode is selected, a solenoid is actuated (F5) to shift the deflector 17 of the sorter 1 to direct the sheet (transfer sheet) S to the first sheet passage 11. The bin unit 9 is moved until the first bin B1 is opposed to the upper discharging roller couple 13 (F6). The bin unit 9 is provided with a flag on the bin supporting frame 19 at this position, so that an unshown second sensor is capable of detecting the flag when the bin unit 9 moves to such an extent that the first bin B1 reaches this position. When the number of copies to be taken is 1, one sheet S per original P is discharged by the upper discharging roller couple 13 to the first bin B1. When the number is plural, a preset number of sheets S per original P are discharged from the upper discharging roller couple 13 to the first bin B1. Usually, the number of copies to be taken is one in the non-sort mode, and the following description will be made for this case with the stapling mode being selected. In response to a detection signal from the second sensor (F7), the copying machine 1102 starts the copying operation (F8). Then, the originals P are sequentially fed from the automatic document feeder 1103, and the sheets S are discharged onto the first bin B1 until a document feeder empty signal is transmitted to a controlling station of the copying machine 1102. After the signal is received by the controlling station, the copying operation of the last original P is completed (F9). Then, the sorter 1 receives a copy completion signal. The description is made as to whether the sheets S are to be stapled or not (F10). When the stapling mode is selected, the bin unit 9 is moved until the first bin B1 is faced to the stapling position adjacent to the lower discharging roller couple 15 (F11) after the last sheet S is received. The position of the first bin B1 in this stapling position is the same as the position of the first bin B1 faced to the lower discharging roller couple 15 to receive the sheets in the sort mode (Figure 5), and the first sensor corresponding to this position detects the flag of the bin supporting frame 19 (F12) to control the bin position. After completion of this movement of the bin unit 9, the electric stapler 45 operates (F13) to staple the sheets S which have been discharged by the upper discharging roller couple 13 and have been accommodated on the first bin B1. If the operator selects the non-sort mode at the initial mode setting, but wants to staple them after the sheets P have been discharged onto the first bin B1 by the upper discharging roller couple 13, the manual stapling switch 1047 shown in Figure 9 is actuated (F14). In response to a signal indicative of this, the bin unit 9 moves until the first bin B1 reaches the position corresponding to the stapling position, and thereafter, the stapling operation is effected in the similar manner (F13). The operations in the non-sort mode have been described, and the next description is concerned with the sort mode. First, the discrimination is made as to whether the number of copies to be copied is one or not (F15). If the number is one, the same control as that of the non-sort mode is automatically selected. If the number is more than one, the solenoid is not energized after the copy starting switch is actuated (F16). Therefore, the deflector 17 directs the sheet to the second sheet passage 12. The bin unit 9 is moved so that the first bin B1 is opposed to the lower discharging roller couple 15 to receive the sheets S on the first bin B1 (F17). This position is detected by the first sensor in the manner similar to that described above (F18). After the movement of the bins, a copy start permitting signal is produced (F19), in response to which operations of the copying machine 1102 and the sorter 1 are initiated (F20). The sheets S corresponding to the originals P are continuously discharged until a no-document signal is transmitted to the controlling station of the copying machine 1102, and the sheets are sorted and accommodated on a number of bins equal to the number of copies to be taken. After the no-document signal is received by the controlling station, the copying operation of the last original is completed (F21). The sorter 1 receives the copy completion signal (F22). The controlling station discriminates whether the stapling mode is selected or not (F23). When the stapling mode is selected, the stapling operation starts with the bin which has received the last sheet (F24). After completion of the stapling of the sheets on the bin B, the sheets S on the next bin are stapled. This continues until the last bin (the first bin B1), for example, is subjected to the stapling operation, and, then, the stapling completion signal is produced, and the electric stapler 45 stops its operation (F25). If the stapling mode is not selected with the initial mode setting, but the stapling is wanted after the sheets are sorted and discharged, the operator actuates the manual stapling switch 1047 after the sheets are accommodated, similarly to the case of the non-sort mode. In response to the signal indicative of this, the stapling operation starts with the bin having received the last sheet. After the completion of the stapling operation, in the non-sort mode it is possible, that the bin is moved to a position corresponding to the first sheet passage 11 to simplify the taking out of the sheet for the operator. The image forming unit 1101 is operated under the control of a control circuit shown in Figure 11 which is self explanatory. As described in the foregoing, according to this embodiment, the stapling means is disposed at the sheet discharging means for discharging the sheet to be sorted; when the stapling is wanted when the sheets are not to be sorted, the bin for receiving the non-sorted sheets which is opposed to the sheet discharging means for the non-sorted sheets, is moved to a position opposing the sheet discharging means for discharging the sheets to be sorted, and the sheets thereon are stapled by the same stapling means, by means of the non-sort sheet stapling controller. Therefore, the non-sorted sheets are moved to a position opposing the sheet discharging means where the stapling means is disposed, so that the non-sorted sheets can be stapled. Accordingly, a convenient sheet sorter can be provided. Referring to Figure 13 the description will be made as to the stapler and alignment means, wherein the same reference numerals are assigned to elements corresponding to those of the Figure 1 embodiment. A supporting frame 123 is fixed to the left side of the base portion of the bin frame 19. On the supporting plate 123, a rotation shaft 127 having an upper end fixed to an upper arm 125 and a lower end fixed to a lower arm 126, is rotatably mounted by an unshown rotational shaft mounted on the supporting plate 123 and by a rotational shaft 129 mounted on the bin cover 21. On the supporting plate 123, a sector gear 131 is rotatably supported about a rotational shaft mounted on the supporting plate 123, wherein the lower arm 126 is fixed to the sector gear 131. Further, below the supporting plate 123, a pulse motor 132 is disposed. A gear 133 fixed to the output shaft of the pulse motor 132 is meshed with the sector gear 131. An aligning rod 25 extends between an end of the lower arm 126 and an end of the upper arm 125, and is penetrated through cut-away portions 23 formed in all of the bins B. The aligning rod 25 is swingable by the rotation of the sector gear 131. The lower arm 126 is provided with a light blocking point 137, which rotates integrally with the lower arm 126, whereby a home position sensor 139 disposed at the left side of the bin frame 19 is actuated. Each of the bins B accommodated in the bin unit 9 is provided with the trunnions 30 at the longitudinal base side ends. The trunnions 30 are projected through the slits 27 formed in the vertical portions 19a of the bin frame 19, and are engaged with and stacked in the guide rails 7 (Figure 14). In this embodiment, the guide rail 7 extends straight in the vertical direction. The bottommost trunnion 30 is in contact with the lower guide roller 31 rotatably supported on the vertical portion 19a of the bin frame 19, whereas the topmost trunnion is contacted to the upper guide roller 32 rotatably supported on the vertical portion 19a of the bin frame 19. Therefore, the bin B are supported in the bin unit 9 with intervals therebetween which are equal to the diameter of the trunnions 30. The bin unit 9 is movable vertically along the guide rail with the upper guide roller 32 and the lower guide roller 31 being engaged with the guide rails 7. Adjacent to the lower discharging roller couple 15, an electric stapler 45 for stapling the sheets accommodated on the bin B is disposed, which is provided with a solenoid 156 and a stapler spring 157 (Fig. 16). The electric stapler 45 is rotatable about a pivot 159, and is normally abutted to a stopper 160 to take a retracted position (solid line position) outside the sheet path. When the sheets S on the bin B are to be stapled, it is displaced to the chain line position to staple the sheets on the bin B opposing the lower discharging roller couple 15. A microswitch 161 (shown in Figure 16) serves to detect the electric stapler 45 moved to the sheet stapling position. In operation, the sheet S discharged from the image forming apparatus such as a copying machine is selectively directed to the first sheet passage 11 or to the second sheet passage 12 by the deflector 17 from the sheet inlet 10, depending on the mode selected, i.e. the non-sort mode or the sort mode. When the non-sort mode is selected, the sheet is discharged to and received by the first bin B1 of the bin unit 9 by means of the upper discharging roller couple 13 through the first sheet passage 11. When the sort mode is selected, the lead cam 40 rotates to sequentially move the trunnions 30 by the helical cam thereof, to provide two expanded portion X and X with the bin B opposed to the lower discharging roller couple 15, wherein the expanded portion is larger than the space between the other adjacent bins. By the moving trunnions 30, the upper guide roller 32 or the lower guide roller 31 is urged so that the bin unit 9 moves as a whole. The sheets S are discharged sequentially by the lower discharging roller couple 15 through the second sheet passage 12, and are received by the first bin B1 and the subsequent bins, sequentially. As shown in Figure 17, when the sheet S is discharged onto the bin Bb opposing the lower discharging roller couple 15, the sheet S moves toward a trailing edge stopper B' by its own weight, since the trailing edge side of the bin Bb is inclined downwardly. In addition, the aligning rod 25 is moved from its retracted position 25' over a predetermined distance in the direction indicated by an arrow by the pulse motor 132 rotating in accordance with a pulse signal corresponding to the size of the sheet, by which a lateral edge of the sheet S is abutted to an alignment reference member 122. The aligning rod 25 is returned to the retracted position to be prepared for the next sheet discharge, after it has been moved over the predetermined distance. By repeating the above operation, a plurality of sheets S are accommodated on a bin Bb with their lateral edges aligned with the alignment reference member 122 and with their trailing edges aligned with the trailing edge stopper B'. The aligning rod 25 penetrates through all of the bins B, and, therefore, the sheets S received by the other bins B are similarly aligned. Now, it is possible that the sheets S discharged to and accommodated by the bins B are stapled. If the stapling mode is not selected, the operation of the sorter 1 is terminated here. If the stapling mode is selected, the solenoid 156 is actuated by a stapling start signal, wherein the electric stapler 45 is pulled by the solenoid 156 to rotate about the pivot 159 to the stapling position indicated by solid lines in Figure 17. By this movement, the head 45a of the electric stapler 45 advances to the stapling position through an upper expanded space X formed between the bin Bb accommodating the sheets to be stapled and the upper adjacent bin Ba, as shown in Figure 15, whereas the anvil 45b is moved to the stapling position through the lower expanded portion X. When the electric stapler 45 moves to the stapling position, the microswitch 161 is actuated to produce a permitting signal, in response to which the electric stapler 45 is actuated to staple the sheets S with a staple 162. After this stapling operation, the solenoid 156 is deenergized so that the electric stapler 45 is returned to a position in which it abuts against the stopper 160 by the stapler spring 157. This is the end of the stapling operation. When the stapling operation is performed for a plurality of bins, it is most efficient to start the stapling operation with the last bin B which has received the last discharged sheet. The above-described series of operations start in response to a signal indicative of the completion of the bin shifting operation; then, the next bin shifting operation starts in response to a signal indicative of the completion of the series of operations of the electric stapler 45. By repeating these operations, the stapling operations are automatically performed for all the necessary bins. The number of bin shifting operations is equal to the number of the bin shifting operations during the sorting operation. According to this embodiment, the bin frame 19 of the bin unit 9 is provided with the alignment reference member 122, and, also, the bin unit 9 is provided with a sheet aligning unit including an aligning rod 25. Therefore, the sheets S on the bins B can be aligned with certainty. In addition, since the alignment of the sheets is effected by the movement of the aligning rod 25 penetrated through openings 23 formed in all of the bins B, and since the aligning rod 25 is mounted on the bin unit 9, the sheets S can be aligned by the movement of the aligning rod 25 even during the bin shifting operation as well as immediately after the sheet has been discharged on a bin B. In other words, the sheets S can be aligned at any time except the time during which the sheet S is discharged. Furthermore, the aligning rod 25 is moved by the rotation about the rotational shaft 129 in this embodiment, and the rotational shaft 129 and the alignment reference member 122 are integral with the bin unit 9, whereby the sheets can always stably be aligned. Since two expanded spaces X and X are formed opposed to the electric stapler 45, the head 45a and the anvil 45b of the electric stapler 45 can easily be displaced to the respective stapling positions at the time of the stapling operation, and, in addition, the sheets can be stapled assuredly without interference with the sheets S accommodated on the lower bin B. In this embodiment, the aligning rod 25 and the electric stapler 45 are swingable about respective pivots, but one or both of them may be moved rectilinearly. A further embodiment of the present invention will be described, which is a partly modified embodiment as compared to the above-described embodiment. As shown in Figure 18, a part of front side of the bin frame 19 is formed as a sheet alignment reference 19c, in place of the alignment reference member 122 according to the foregoing embodiment. Since the alignment reference 19c and the bin frame 19 are integral, the sheet alignment reference 19c can be extended to the neighborhood of the stapler 45, as will be understood from the reference sign 19c', so that the width of the sheet alignment reference 19c can be increased to permit a more stabilized sheet aligning operation. Referring to Figure 19, a further embodiment will be described, in which the structure for providing the expanded portions or spaces X and X is modified. An elongated slot 272 is formed in each of the bins B, which is slidably engaged with an end side shaft 271 fixed to the bin slider 20 of the bin unit 9. An arm lever 275 is rotatably mounted on each of base side shafts 273 securedly fixed to the bin frame 219. At one end of the arm lever 275, a trunnion 230 is rotatably mounted by a pin 277. At the other end of the arm lever 275, a pin 279 is mounted which is engaged with a hole of the bin B. By this structure, the bin B is swingably supported on the arm lever 275. The bin B is inclined toward the base side (toward the trailing edge stopper B'), so that it moves downwardly by its weight. A stationary cam plate 290 is fixedly mounted to each of the side plates of the sorter to guide the trunnions 230. When the bin frame 219 moves upwardly, the trunnions 230 together with the bins B move upwardly while being in contact with the cam plate 290. First, the trunnion 230b of the second bin Bb contacted to a first cam surface 290a of the cam plate 290 rotates downwardly about the pin 273b, so that the bin Bb moves substantially parallel to a direction indicated by an arrow G to provide an expanded space between the bin Bb and the lower third bin Bc. On the other hand, as regards the first bin Ba located above the second bin Bb, the trunnion 230a thereof moves along the tapered surface 290b of the cam plate 290 to be brought into contact with a second cam surface 290c thus forming an expanded space X between the first bin Ba and the lower second bin Bb. As a result, two expanded spaces X and X are formed. When the bins B are moved downwardly, two spaces X and X are formed similarly. Referring to Figure 20, another embodiment having another expanding structure will be described. In this embodiment, use is made of a Geneva pulley 391 having slots 392 engageable with the trunnions 330 of the bins B to form two expanded spaces X and X between the bins, simultaneously. The pulley 391 has four engaging slots 392 engageable with the trunnions 330. When the pulley 391 rotates in the direction H, the trunnion 330C of the bin Bc, for example, engages with the slot 392c of the pulley 391, and it moves upwardly along the guiding slot 393 by the rotation of the pulley 391 to a position indicated by the reference sign 330b, where it is stopped. The trunnion 330b of the upper bin Bb placed at the position 330b is moved upwardly to the upper position 330a. In this manner, expanded spaces X and X are formed between the intermediate bin Bb and the upper bin Ba, and between the intermediate bin Bb and the lower bin Bc. During the lowering movement of the bin B, two expanded spaces are formed. The trunnions 330 are rotatably mounted to the respective bins B and are stacked in the guiding slot 393. The bottommost trunnion 330 is urged upwardly by a spring. Referring to Figures 22 - 28, the description will be made as to embodiments of the structure for the sheet alignment. As shown in Figure 22, the bin 410 is provided with engaging plates 446 at the front free end side and at the rear free end side, respectively. The engaging plate 446 engages an unshown supporting plate disposed inside the frame to support the free end side of the bin 410. The bin 410 is further provided with supporting shafts 26 at the front base side and the rear base side thereof, respectively. Each of the supporting shafts 26 has a roller 30 rotatably mounted thereto. The bin 410 has an elongated slot 450 extending a predetermined distance (L) away from the shaft 129. The slot 450 has a length which is longer than the rotational distance through which the alignment rod 125 is movable, and has a width sufficiently larger than the diameter of the alignment rod 125 (minimum width is l ). The downstream surface of the slot 450 with respect to the sheet discharging direction A is tapered (451a in Figure 23). The corner portion 410a of the bin 410 at the free end and rear side is inclined at a predetermined angle with respect to a sheet supporting surface 410b. The base side 410c extends perpendicular to the sheet supporting surface 410b. The bin 410 itself is inclined upwardly toward the free end. By this inclination, the sheet is aligned in the sheet conveying direction by the sheet sliding on the sheet supporting surface 410b so that its trailing edge abuts against the perpendicular portion 410c. A cut-away portion 451b is formed extending from the free end of the bin 451 generally to the center of the sheet supporting surface 410b to facilitate the taking out of small size sheets stacked on the sheet supporting surface 410b, by the operator. In operation, the sheet S discharged from the image forming apparatus after being subjected to an image forming operation is discharged to the topmost bin by the discharging roller couple 15 through the passage 12. At this time, the leading edge of the sheet S passes above the elongated slot 450, but the leading edge of the sheet S is not obstructed by the elongated slot 450 because it is guided by the tapered portion 451a (Figure 23). The sheet S discharged on the bin slides on the bin 451 to abut the base perpendicular portion 410c by the inclination of the bin. However, the sheet S is still spaced apart from the alignment reference plate 122, as shown by chain lines in Figure 24. Then, the pulse motor 132 rotates through a rotational angle determined in accordance with information from the image forming apparatus indicative of the sheet size, so that the alignment rod 25 moves from the home position H in the direction indicated by an arrow in the elongated slot 450, thus moving the sheet S from the chain line position to the solid line position, whereby the sheet S is abutted to and aligned with the alignment reference plate 122 (Figure 24). After a predetermined period of time, the pulse motor 132 is reversed to return the alignment rod 25 to the home position H. In the foregoing embodiment, the elongated slot 450 is formed at a predetermined distance (L) away from the shaft 129 (radius L) with a minimum width l . Alternatively, as shown in Figure 25, the slots 450' may be formed by circumferences having a radius L, and (L + l ) about a shaft 129. As shown in Figures 26 and 27, the portion surrounding the periphery of the elongated slot 450 of the bin 451 may be made thicker with a smooth inclination to form a thick portion 451c. By this, the bin 451 is reinforced, and the sheet S discharged onto the bin is guided upwardly by the thick portion 451c to prevent the sheet S from being obstructed by the elongated slot 450. In the foregoing embodiment, the alignment rod 25 is rotated, but as shown in Figure 28, it (aligning rod 425) may be made movable along a rectilinear line. In that case, the elongated slot 450'' extends straight, by which the contact portion between the elongated slot 450'' and the sheet S is reduced. Therefore, the obstruction by the slot 450'' to the movement of the sheet S is further prevented. As described, according to this embodiment, the bin is provided with an elongated slot for allowing the penetration of an alignment member, so that the alignment member moves through the slot to perform the sheet aligning operation, by which the necessity of an open slot for allowing the insertion of the alignment member is eliminated, so that the strength of the bin can be assured. In addition, the possibility that the sheet is obstructed by the slot resulting in inability of the alignment can be reduced. Also, since only one corner portion 410a at the downstream free end side of the bin with respect to the sheet discharging direction where the alignment member is located, is inclined with respect to the sheet supporting surface 410b, the sheet aligning operation can be performed by the aligning member without obstruction. More particularly, even if there is a cut-away portion 451b for allowing small size sheets to be taken out, the inclined surface 410a is effective to keep the sheets with a certain degree of rigidity when large size sheets are supported on the sheet supporting surface 410b, to prevent the sheets to be flexed; and despite the fact that the inclined portion is not formed at the alignment reference plate 122 side. By providing the tapered surface 451a at the downstream side of the elongated slot 450 with respect to the sheet discharging direction, the sheet is prevented from being obstructed by the elongated slot 450 when it is discharged, so that the sheet can assuredly be received on the bin 451. By forming a thick portion 451c surrounding the periphery of the elongated slot 450, the strength of the bin at the elongated slot 450 can be increased. Referring to Figures 29 - 34, the stapler according to another embodiment will be described in detail. As shown in Figures 29, 30 and 31, the stapler 560 includes a driving motor 561, a gear 562 fixed to an output shaft of the motor 561, wherein a gear 563 is meshed with the gear 562. The gear 563 is connected with a link 565 having an end mounted to the frame of the apparatus. At an articulation 565a of the link 565, a stapling head 566 is disposed. Below the stapling head 566, an anvil 567 is disposed. The stapler 560 is fixedly mounted on a stapler base 571 fixed on a swingable base 570 which is swingable about a shaft 569, so that it can be pivoted together with the swingable base 570. The swingable base 570 is provided with a mounting base 572 carrying a sheet detecting sensor 573 for detecting presence and absence of a sheet adjacent a front and right corner of the stapler 560. The sensor block 573 comprises a light emitting portion 573a and a light receiving portion 573b, and is in the form of a channel. In operation, the swingable base 570 is rotated by an unshown motor to move the stapler 560 from a normal retracted position A to the stapling position B by the rotation about the shaft 569. During this motion, the trailing and front corner of the sheet S on the bin B passes relatively across the space between the light emitting portion 573a and the light receiving portion 573b of the sheet sensor 573 which swings together with the swingable base 570, by which the sheet S is detected by the sensor block 573. If the sheets S on the bin B were inadvertently taken out so that the sensor block 573 does not detect any sheet, a microcomputer prevents the stapling action by the stapler 560 and returns it to the retracted position A. When the microcomputer receives a signal indicative of the presence of the sheet S by the sensor block 573, it drives the motor 561 to allow the stapler 560 to staple the sheets S on the bin B. After the stapling action, the stapler 560 is returned to its retracted position A. The microcomputer rotates the lead cam 40 by the driving motor 42 to lift the bins through one stage, and after the sheet sensor block 573 detects the presence of the sheet S accommodated on the second bin B, the stapler 560 now disposed at the second bin performs the stapling action. By similar operations, the bins B are lifted step by step, and the sets of sheets S on the bins B are sequentially detected by the sheet sensor block 573, and are stapled. When all of the sets of sheets S on the bins B are stapled, the stapling operation is stopped. In the foregoing embodiment, the stapling operation is performed after completion of the sorting and accommodation of the sheets S, but it is a possible alternative that a set of sheets S is stapled each time the final sheet S is discharged on the bin. In the foregoing embodiment, a transparent type sensor movable together with the stapler 560 is used as the sheet detecting sensor block 573, but it is a possible alternative that a reflecting type sensor fixedly mounted to the frame may be used, as shown in Figure 34A. The mounting of the sensor 673 is easy if the sorter 1 is of the type in which the bins B are movable horizontally (sheet discharging direction), as shown in Figure 34B. In the foregoing embodiment, the sheet sensor is movable integrally with the stapler 560, but the sensor may be independently rotatable. In the foregoing embodiment, the sheet sensor block 573 is mounted to the swingable base 570 by means of the mounting base 572, but the light emitting portion 573a and the light receiving portion 573b of the sheet sensor 573 may be mounted to the head 566 and the anvil 567 of the stapler 560, respectively. As described in the foregoing, according to this embodiment, there is provided a detecting means for detecting the sheets accommodated on the bin on which the stapler acts, and the stapling operation is allowed only when the detecting means detects the sheet on the bin. Therefore, the stapler is prevented from performing the stapling action without sheets, which can result in jam of staples. By mounting the detecting means on the stapling device, it is possible to detect presence or absence of the sheets to be stapled during moving the stapler to the stapling position, whereby a particular time is not required for the detection. Therefore, the post processing operation can be speedily and efficiently performed. Referring to Figures 35 - 39, another embodiment will be described by which the sheets which have been curled at their leading edges can suitably be stapled. As shown in Figures 35 and 36, the frame 6 has a shaft 569 mounted thereon, on which a swingable base 570 is rotatably supported. The swingable base 570 has a stapler base 571 fixedly mounted thereto. The stapler base 571 carries a stapler 560. To the frame 6, a gear box G containing reduction gears 675 is mounted, and to the gear box G a motor 676 is mounted. The motor 676 has an output shaft to which a gear 677 is fixedly mounted. The gear 677 is meshed with an input gear 675a of the gear train 675. The gear train 675 has an output shaft 675b to which a link disk 679 is mounted. At the outer periphery of the link disk 679, cams 679a and 679b are disposed, and they serve to actuate or deactuate a microswitch 680 which is mounted on the frame 6 to energize the motor 676. Adjacent the outer periphery of the disk 679, a shaft 679c is mounted. To the swingable base 570, a link arm 681 is connected for rotation in a horizontal plane. The link arm 681 is provided with a shaft 681a and has an elongated slot 681b. Through the slot 681b, the shaft 679c is penetrated, and a spring 682 is stretched between the shaft 679c and the shaft 681a. In the neighborhood of the shaft 569, a bell crank arm 683 made of resin material or the like is rotatably supported. An end 683a of the arm 683 is contacted to an end 570a of the swingable base 570, and the other end 683b is contactable to a microswitch 685 for detecting the stapler when it is displaced at its stapling position. To the swingable base 570, a sheet sensor block 573 for detecting presence and absence of the sheets is mounted by means of a mounting base 572 (Figure 29). The sensor block 573 comprises a transparent type sensor having a channel shape and comprising a light emitting portion 573a and a light receiving portion 573b. In operation, when a preset numbers of stacks of sheets S are sorted and accommodated on the respective bins after being printed, the microcomputer drives the driving motor 42 to rotate the lead cam 40 to place the topmost bin to the stapling position, that is, the position for receiving a sheet S discharged by the discharging roller couple 15. Then, the computer instructs the motor 676 to rotate, and the rotation of the motor 676 is reduced by the gear train 675 and is transmitted to the output shaft 675b. By this, the link disk 679 rotates in the clockwise direction. When the stapler 560 is at its retracted position A (Figure 29), the cam portion 679b is in contact with the microswitch 680 to close it. However, by the clockwise rotation of the disk 679, the cam portion 679b is brought out of contact with the switch 680 to open it. Further, the clockwise rotation of the link disk 679 is transmitted to the link arm 681 from the shaft 679c to the spring 682 and the shaft 681a. Then, the arm 681 swings about the shaft 679c inserted in the slot 681b in the leftward direction (Figure 36). By the movement of the link arm 681, the swingable base 570 swings about the shaft 569. When the link disk 679 further rotates, the cam portion 679a is brought into contact with the microswitch 680 to close it. The microcomputer receives the on-signal from the switch 680 and deenergizes the motor 676 to stop the link disk 679. At this time, the swingable base 570 is at a position shown in Figure 36. The end 570a of the base 570 (Figure 36) pushes the end 683a of the arm 683 to rotate the arm 683 in the counter-clockwise direction. By this, the other end 683b of the arm 683 presses the microswitch 685 to actuate the switch 685. The microcomputer receives the on-signal of the switch 685 to detect that the stapler 560 has been moved to the stapling position B (Figure 29). When the stapler 560 moves from the retracted position A to the stapling position B, the sheets S accommodated on the bin are guided by upper and lower guides 574 and 674 (Fig. 31) into the space between the head 566 of the stapler 560 and the anvil 567. If the sheet S on the bin is curled, the curl of the sheet S is confined by the upper and lower guides 574 and 674, and the sheet is guided into the space between the head 566 and the anvil 567. During this, the set of sheets S is detected by the sensor block 573 by the trailing end front corner of the sheets S on the bin B passing through the space between the light emitting portion 573a and the light receiving portion 573b of the sheet sensor block 573 which integrally moves with the swingable base 570. If the sensor block 573 does not detect the sheets S for the reason that, for example, the sheets S have inadvertently been taken out from the bin by the operator, the microcomputer does not allow the stapler 560 to operate but causes it to return to the retracted position A. When the microcomputer receives a signal indicative of the presence of the sheets S from the sensor block 573, it instructs to drive the driving motor 561 to make the stapler 560 staple the sheets S on the bin. After the stapling operation, the stapler 560 is returned to the retracted position A. In the foregoing embodiment, the sheet sensor block 573 is in the form of a channel and has generally a rectangular cross section. Alternatively it is possible that, as shown in Figures 37A and 37B, a tapered surface 573c is formed, wherein an upper guide 686 is provided on the same surface as the afore-mentioned upper guide 574, and a lower guide 687 is provided on the same surface as the aforementioned lower guide 674. By this, when the sheet accommodated on the bin is curled, the curl can be confined by the upper and lower guides 686 and 687 to prevent the sheet detecting sensor 573 from contacting the curled sheet S and folding it. By making the distance between the light emitting portion 573a and the light receiving portion 573b of the sensor block 573 sufficiently larger than the distance between the upper and lower guides 574 and 674, the sensor block 573 can be effectively prevented from contacting the sheet S. In the foregoing embodiment, the description has been made as to the case where the upper and lower guides 574 and 674 are employed as a means for confining the curled sheet. However, it is a possible alternative that, as shown in Figure 38, a curled sheet confining member 789 is employed which is insertable and retractable with respect to the bin unit. The curled sheet confining member 789 includes a gear 790 connected to an unshown motor, a gear 791 meshed with the gear 790 and a curled sheet confining rod 793 filed to a shaft 792 of the gear 791. The rod 793 swings to confine the curled sheet. In the foregoing embodiment, the upper and lower guides 574 and 674 are used for confining the curled sheet. It is a possible alternative that, as shown in Figure 39, a sheet confining spring 895 constituted by a leaf spring or the like is provided at a base side of each of the bins B. The curled sheet is confined by the confining spring 895 mounted to the adjacent upper bin B. As described in the foregoing, according to this embodiment, there is provided a curl confining means to confine the curled sheet which is to be stapled by the stapler, by which the sheet is prevented from being contacted by the stapler and being folded or being disturbed, which can result in improper stapling. Referring to Figures 40, 41, 42 and 43, a mechanism for positioning the stapling device will be described. At the front side of the sorter 1, there is provided an automatic (electric) stapler 955 for stapling the sheets accommodated in each of the bins B, facing a lower couple of discharging rollers 15. The automatic stapler 955 includes a solenoid 956 and a stapler spring 957. The solenoid 956 has a link 956a to which a link pin 971 is fixedly mounted, and a solenoid spring 973 is stretched between the link pin 971 and a stapler pin 972 of the automatic stapler 955. The link 956a is engaged with the stapler pin 972 through a slot formed in an end portion of the link 956a. To the automatic stapler 955, a stapling position stopper 976 is fixedly mounted, and the stapler 955 is normally placed outside the path of the sheet (solid line position) by being contacted to a stopper 960 by the function of the stapler spring 957. When the sheets S on the bin B are to be stapled, the solenoid 956 is operated to move the stapler 955 to the position shown by chain lines where the stapling position stopper 976 is abutted to a sheet alignment reference 919c of the bin frame 919. Then, the sheets S accommodated in the bin B opposed to the lower couple of the discharging rollers 15 are stapled. In Figure 40, the reference numeral 961 indicates a microswitch for detecting that the stapler 955 is placed at the stapling position, and for producing a detection signal. When a stapling mode is selected, the solenoid 956 is actuated in response to a stapling start signal. The automatic stapler 955 rotatingly moves about a pivot 959 by the solenoid 956 and is moved to its stapling position so that the stapling position stopper 976 is abutted to the sheet alignment reference 919c, by which the stapler 955 is correctly positioned. At this time, the head portion 955a of the stapler 955 (as shown in Figure 40) is moved to the stapling position through an upper opening portion X formed between the bin Bb accommodating the sheets to be stapled and the adjacent upper bin Ba, and the anvil portion 955b is moved to the stapling position through a lower opening portion X, that is the opening formed between the bin Bb and the adjacent lower bin. As shown in Figure 40, when the automatic stapler 955 is positioned at the stapling position, the microswitch 961 is actuated, so that a stapling permitting signal is produced, in response to which the stapler 955 is driven, by which the sheets S are stapled by the staple 962. After completion of the stapling operation, the solenoid 956 is deactuated, and the stapler 955 is returned by the function of the stapler spring 957 to be contacted to the stopper 960. Thus, the stapling operation for one bin terminates. When the stapling operations are carried out for a plurality of bins B, it is most efficient if the stapling operation starts from the last bin B to which the last sheet was discharged. After the stapler 955 operation in response to a signal indicative of the completion of the bin shiftings, the bin is shifted in response to a signal indicative of the completion of the stapler 955 operations; and these operations are repeated until the stapling operation is effected for each of the bins. The number of the bin shifts for the automatic stapling corresponds to the number of bin shifts at the time of the sorting operation. Referring to Figures 42 and 43, another embodiment will be described in which the mechanism for positioning the automatic stapler 955 at the stapling position is partly modified. In this embodiment, a frame guide 877 for guiding the bin frame 919 is disposed at the front side of the sorter 1, and an end of the bin frame 919 is slidably engaged in a guiding groove 877a of the frame guide 877. On the other hand, the automatic stapler 955 has a stapling position stopper 876 fixedly mounted thereto, which abuts the frame guide 877 to position the automatic stapler 955 at its stapling position when it is moved to the stapling position. In operation, when a sheet S is discharged onto the bin B, the sheet S is aligned along a sheet alignment reference 919c of the bin frame 919 which is correctly positioned by the frame guide 877, as shown in Figure 43. When the sheet stapling operation is carried out, the stapler 955 is moved to the stapling position and is abutted to and positioned by the frame guide 877 for guiding and positioning the sheet alignment reference 919c, so that the sheet accommodated in the bin B can be stapled. In this embodiment, the sorter has vertically movable bins, wherein the stapler is positioned and rotatable at a predetermined level. However, the sorter may be of a stationary bin type, and the stapler may be of an elevatable type. As described in the foregoing, according to this embodiment, a sheet alignment reference member is provided which functions as a reference for aligning the sheets, and a portion substantially integral with the sheet alignment reference member functions as means for positioning the stapler at the stapling position, whereby the stapling position of the stapler can be correctly determined relative to the sheets, and, therefore, the sheets can be correctly and assuredly stapled.

Claims: A method for controlling a sheet sorter (1) which includes a plurality of bins (B) for accommodating sheets (S), said bins (B) being arranged in a vertical direction, a first sheet discharging means (13) for discharging sheets (S) not to be sorted, a second sheet discharging means (15) disposed at a vertical interval from said first sheet discharging means (13), for discharging sheets (S) to be sorted, and bin moving means (39 - 43) for moving said bins (B) substantially vertically, wherein, when a sorting mode is selected, the sheets (S) are accommodated on said plurality of bins (B) by sequentially opposing said bins (B) to said second discharging means (15), and wherein, when a non-sorting mode is selected, the sheets (S) are discharged by said first discharging means (13) and accommodated on a non-sort bin (B1) opposed to said first discharging means (13), characterized by stapling the sheets (S) on said bins (B) by a stapling means (45, 560, 955) provided adjacent to said second sheet discharging means (15) when said sorting mode is selected, and moving said non-sort bin (B1) to a neighborhood of said second discharging means (15) where the sheets (S) thereon are stapled by said stapling means (45, 560, 955) when said non-sorting mode is selected. A method according to claim 1, characterized in that, when said sorting mode is selected, said bins (B) having received the sheets (S) are sequentially moved to sequentially oppose said stapling means (45, 560, 955). A method according to claim 1 or 2, characterized by aligning a sheet (S) each time it is discharged onto a bin (B), by means of an aligning means (25) actuable on all of said bins (B). A method according to one of the preceding claims, wherein, after the sheets (S) have been accommodated on said non-sort bin (B1) when said non-sorting mode is selected, said non-sort bin (B1) moves to a position corresponding to the stapling position, where the sheets (S) on said non-sort bin (B1) are stapled when a switching means (1047) for manually operating said stapling means (45, 560, 955) has been actuated.

Inventors: HIROI MASAKAZU, HONJO TAKESHI, KOBAYASHI KENJI, MURAKAMI KOICHI, NAITO MASATAKA, SAITO JUN, SHIDO HIRONORI, HIROI, MASAKAZU, HONJO, TAKESHI, KOBAYASHI, KENJI, MURAKAMI, KOICHI, NAITO, MASATAKA, SAITO, JUN, SHIDO, HIRONORI
Applicants: CANON KK, CANON KABUSHIKI KAISHA
Application year: 1988
Main classification: B65H39
IPC codes: G03G15, B42C1, B65H39, B65H31, B65H43, B42B4