Finisher for finishing paper sheets

A finisher for positioning stacks of paper sheets each being loaded on individual bins of a sorter and stapling the positioned stacks by a stapler one at a time. The finisher has a paper pulling device for pulling a stack of paper sheets to a stapling position of the stapler. The paper pulling device has an upper and a lower chuck which cooperate to grip the stack of paper sheets at a plurality of points of the latter. The upper and lower chucks are mounted on the free ends of an upper and a lower rotatable lever, respectively.

BACKGROUND OF THE INVENTION 
The present invention relates to a finisher having a stapler for stapling 
stacks of paper sheets distributed to individual bins of a sorter and, 
more particularly, to a finisher having means for shifting a paper stack 
to a stapling position. 
A finisher for positioning paper sheets sequentially distributed to 
individual bins of a sorter and stapling each stack of such paper sheets 
by a stapler has been proposed in various forms in the past. A 
prerequisite with this type of finisher is that a stack of paper 
distributed and discharged onto a bin be moved to a stapling position. 
This prerequisite has customarily been met by use of a mechanism which 
moves a stapler toward a bin or a mechanism which moves a bin toward a 
stapler. This kind of scheme, however, increases the overall scale of the 
finisher. Moreover, since the mechanism, whether it moves a stapler or a 
bin, does not directly handle a paper stack, it is difficult to maintain 
the stapling position constant. 
To eliminate the above drawbacks, a paper stack may be pulled to the 
stapling position of a stapler by a paper pulling device, as also proposed 
in the art. Specifically, a paper pulling device has a pair of chucks for 
chucking a paper stack and moves them between a chucking position and a 
stapling position in the horizontal direction. The coactive chucks are 
rotatable toward each other to grip a paper stack and away from each other 
to release it. However, paper pulling devices heretofore proposed have 
some problems left unsolved regarding the applicability thereof to a 
finisher, as will be described specifically later. 
SUMMARY OF THE INVENTION 
It is therefore an object of the present invention to provide a finisher 
capable of surely stapling a paper stack while maintaining it in a neatly 
arranged position. 
It is another object of the present invention to provide a finisher which 
prevents a paper stack from being stapled at an unexpected point thereof 
by freeing it from skew in the event of pulling. 
It still another object of the present invention to provide a finisher 
which with a simple construction allows an upper and a lower chuck to 
surely chuck and pull a paper stack without the lower chuck contacting 
paper sheets having been accommodated in bins other than a bin of 
interest. 
It is yet another object of the present invention to provide a finisher 
capable of moving a paper pulling device in a substantially constant 
acceleration motion and, therefore, pulling and stapling a paper stack 
without disturbing the individual papers of the stack. 
It is a further object of the present invention to provide a finisher 
capable of pressing paper sheets and surely chucking and pulling a paper 
stack with a simple construction. 
A finisher for finishing paper sheets of the present invention comprises a 
sorter having a plurality of bins arranged one upon another for receiving 
paper sheets transported thereto, a stapler for stapling stacks of paper 
sheets discharged onto the bins, and a paper pulling device for pulling 
the paper stacks of paper sheets positioned on the bins to a stapling 
position of the stapler one at a time. The paper pulling device comprises 
chucks for chucking the stack of paper sheets at a plurality of points of 
the stack.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
To better understand the present invention, a brief reference will be made 
to conventional implementations for pulling a stack of paper sheets to a 
stapling position of a stapler. 
FIGS. 1 and 2 each show a different prior art paper pulling device, 
particularly a stack of curled paper sheets and how such a stack is caught 
by chucks. In the figures, there are shown bins 350 of a sorter, an upper 
rotatable lever 622, a lower rotatable lever 624, an upper chuck 623, and 
a lower chuck 625. A stack of paper sheets is generally labeled P. Assume 
that the upper and lower chucks 623 and 625 rotate over a substantial 
angular range and over distances L.sub.1 and L.sub.2 which are 
substantially the same, as shown in FIG. 1. Then, when the chucks 623 and 
625 chuck the upper paper stack P.sub.1, the lower chuck 625 is apt to 
catch the lower paper stack P.sub.2 which is curled. To eliminate this 
problem, it has been proposed to make the distance L.sub.2 smaller than 
the distance L.sub.1, as shown in FIG. 2. The relation L.sub.2 &lt;L.sub.1 
has customarily been set up by changing the gear teeth ratio and leverage 
of gears which drive the upper and lower levers 622 and 624. This scheme, 
however, is not practicable without complicating the construction and 
needing an extra space and, therefore, extra cost. 
FIG. 3 schematically shows a traditional paper stack pulling device. There 
are shown in FIG. 3 a pulling member 615 and a stapler 701 having an 
opening 701a. The pulling member 615 moves into a notch formed in the bin 
350, chucks a paper stack loaded on the bin 350, and then pulls the paper 
stack into the opening 701a of the stapler 701. At this instant, if the 
paper stack has been curled, it is likely that the pulling member 615 
fails to surely chuck the whole paper stack and, therefore, to bring it 
into the opening 701a of the stapler 701. FIG. 4 shows a specific 
configuration of a conventional mechanism for pressing such a curled paper 
stack. In FIG. 4, each bin 350 is provided with a guide 702 for guiding a 
paper stack toward the opening 701a of the stapler 701. This kind of 
approach has a problem that the guides 702 have to be affixed to the bins 
one by one by time- and labor-consuming operations, resulting in an 
increase in cost. Moreover, the cost increases with the increase in the 
number of bins 350. 
When the above-described type of paper pulling device is constructed to 
grip a paper stack with chucks at a single point of the stack, a moment is 
apt to act on the stack due to inertia in the event of pulling and to 
thereby cause the latter to skew. The skew would prevent the stapling 
position from being maintained constant. 
The paper pulling device with the above construction is movable back and 
forth between a chucking position for chucking a paper stack on the bin 
350 and a stapling position for stapling it. Such a movement of the device 
is implemented by a DC motor and a ball screw. However, the use of a DC 
motor is disadvantageous for some reasons. Specifically, since the 
movement of the pulling device is effected by the start-up portions of the 
DC motor, it is difficult to control the rotation of the motor, i.e., to 
accelerate it constantly. Further, when the ball screw or similar load is 
not constant, the rotation of the DC motor itself fluctuates, rendering 
the control over the acceleration more difficult. 
Referring to FIG. 5, a finisher embodying the present invention is shown 
which is free from the various drawbacks particular to the prior 
implementations as discussed above. As shown, the finisher has an inlet A 
for receiving copy sheets which are sequentially driven out of a copier or 
similar equipment. Inlet guides 101 and 102 are located at the inlet A 
while a selector in the form of a pawl 103 is located downstream of the 
inlet guides 101 and 102. An upper transport section 100 extends upward 
from the pawl 103 and includes, in addition to the inlet guide 101, guides 
110 and 114, transport or drive rollers 108, driven rollers 109, a 
discharge or drive roller 111, a driven roller 115, and a proof tray 116. 
A skew section 200 extends downward from the pawl 103 and includes a skew 
guide 308, a driven guide 217, a guide plate 308, driven guide plates 308 
and 309, an inlet roller 201, skew rollers 202, an outlet roller 203, 
driven rollers 214 and 216, and balls 215. The skew section 200 terminates 
at a deflecting section B via transport rollers 301 and 302 and driven 
rollers 305 and 306. 
A deflecting pawl and a discharge roller 304 are associated with each bin 
350 in the deflecting section B. Driven rollers 307 each is pressed 
against a respective one of the discharge rollers 304 with the 
intermediary of a vertical transport path. A proof motor 117 drives the 
transport rollers 108 and outlet roller 111 while a drive motor 313 drives 
the inlet roller, screw rollers 202, outlet roller 203, transport rollers 
301 and 302, and discharge rollers 304. A pulse generator 315 is provided 
in a driving section so as to generate pulses proportional in number to 
the rotations of the motor 313. 
As shown in a plan view in FIG. 6, a stapler device 700 is located at one 
side of the group of bins 350 and has a stapler 701, a pulling device or 
chucking section 615 for pulling a paper stack to the stapler 701, and a 
mechanism for moving the stapler 701 and chucking section 615 up and down 
to the individual bins. A jogging device 500 is disposed at the other side 
of the group of bins 350 and has a jogger shaft 502 for positioning a 
paper sheet before a stapling operation, and an arrangement for moving the 
shaft 502 to a size matching a particular paper size. A positioning roller 
device 550 is positioned in close proximity to that side of the bin 350 
where the stapler unit 700 is located. 
As shown in FIG. 5, the finisher or sorter has twenty bins in total. A bin 
sensor 321 and a paper sensor 322 are located in an upper portion of the 
sorter while a bin sensor 323 and a paper sensor 324 are located in a 
lower portion of the same. The sensors 321 to 324 each is implemented as 
an optical sensor made up of an LED (Light Emitting Diode) and a 
phototransistor. The paper sensors 322 and 324 are responsive to the 
discharge of paper sheets, and the bin sensors 321 and 323 are responsive 
to the presence of paper sheets in the bins 350. A discharge sensor 125 is 
associated with the upper transport path 100 to see if paper sheets, or 
copy sheets, have been driven out onto the proof tray 116. An inlet sensor 
314 is provided in the lower transport section 300 for implementing, for 
example, the timings at which paper sheets should be distributed to the 
individual bins 350. The sensors 115 and 314 each comprises a 
photointerrupter with an actuator. 
FIGS. 7 and 8A show the upper transport section 100 in detail in a front 
view and a side elevation, respectively. A paper sheet or copy sheet 
driven out of the copier body is guided by the guides 101 and 102 toward 
the pawl 103. The pawl 103 is connected to a solenoid (SOL) 107 by links 
104, 105 and 106. When the solenoid 107 is turned off, the pawl 103 steers 
the paper sheet toward the skew section 200 located below the transport 
section 100. When the solenoid 107 is turned on, the pawl 103 feeds the 
paper sheet into the upper transport section 100. 
Specifically, on the turn-on of the solenoid 107, the pawl 103 steers the 
paper sheet toward the transport roller 108 disposed immediately above the 
pawl 103. The transport roller 108 is made of EPDM or chloroprene rubber. 
The driven roller 109 associated with the transport roller 108 is 
constantly pressed against the latter by a leaf spring or similar biasing 
member. Three pairs of such transport and driven rollers 108 and 109 are 
arranged along the upper transport path 100 to drive the paper sheet 
upward toward the proof tray 116 through between the guides 101 and 110. 
The driven rollers 109 and pawl 103 are mounted on the guide 110. As shown 
in FIG. 8B, the guide 110 is hinged to the framework of the sorter by a 
pin 112 so that it may be opened to uncover the pawl 103 and driven 
rollers 109. This will promote easy work in the event of a paper jam or 
similar occurrence. 
The paper sheet is guided by the guides 101 and 114 to reach the outlet 
roller 111 which is also made of EPDM or chloroprene rubber. The driven 
roller 115 is constantly pressed against the outlet roller 111 by a leaf 
spring or similar biasing member. The rollers 111 and 115 cooperate to 
drive the paper sheet onto the proof tray 116. As shown in FIG. 5, the 
proof tray 116 is located closer to the copier body, i.e., the operator 
than the bins 350. This not only allows the operator to see and pick up 
the copy sheets with ease but also reduces the paper transport distance 
and, therefore, transport time to the proof tray 116. If desired, the 
proof tray 116 may be implemented as a part of an upper cover of the 
sorter. 
FIG. 9 shows a drive mechanism associated with the upper transport section 
100. As shown, the upper transport section 100 has an exclusive motor 117. 
The rotation of the motor 117 is transmitted to the transport rollers 108 
and outlet roller 111 via gears 130 and 131, a timing belt 118, and timing 
pulleys 119 and 120. The timing pulleys 119 and 120 are affixed 
respectively to the shafts of the transport rollers 108 and outlet roller 
111. 
It is noteworthy that the upper transport section 100 does not have any 
transport roller between the pawl 103 and the output of the copier body. 
In such a configuration, in an operation mode which uses the proof tray 
116, a copy sheet is transported with only the motor 100 of the upper 
transport section 100 and the solenoid 107 being operated. On the other 
hand, in an operation mode which uses the bins 350, the drive motor 117 
and solenoid 107 do not have to be powered. This is desirable from an 
efficient power supply standpoint. In addition, the two fully independent 
transport paths promote easy jam recovery, for example. 
The upper transport section 100 is constructed into a unit and is easy to 
remove. FIG. 10 shows another specific configuration of the upper 
transport section 100, i.e., a unit U having an inlet A.sub.1. It will be 
seen that the finisher is usable with a copier body having an outlet at a 
different level only if the unit U is replaced with another. In FIG. 10, 
the same components as those shown in FIG. 5 are designated by the same 
reference numerals. 
Referring again to FIG. 5, the skew section 200 is a unit for changing, 
when a paper sheet is driven out of the copier body with the center 
thereof being used as a reference, the reference to the front edge of the 
paper sheet within the transport path. The skew section 200 is situated in 
the vertical portion below the pawl 103. Using the vertical portion is 
successful in reducing the overall size of the sorter. 
In a sort or stack mode which uses the bins 350, the paper sheet or copy 
sheet fed from the copier body is steered by the pawl 103 toward the inlet 
roller 201 of the skew section 200. The inlet roller 201 is made of EPDM 
or chloroprene rubber. The driven roller 214 is constantly pressed against 
the inlet roller 201 by a leaf spring or similar biasing member. 
FIG. 11 shows a part of the skew section 200 where the skew rollers 202 are 
positioned. As shown, the two skew rollers 202 each is inclined by about 
25 to 30 degrees such that the paper sheet is directed toward a reference 
guide 204. The skew rollers 202 are also made of EPDM or chloroprene 
rubber. As shown in FIG. 12, the driven rollers 215 associated with the 
skew rollers 202 each is implemented with a ball 215 which is biased by a 
compression spring 218. Such a configuration increases the freedom 
regarding the rotating direction of a paper sheet and, when the copy 
sheets abut against the reference guide 204, prevent it from being bent or 
otherwise deformed. The paper sheet driven askew into abutment against the 
reference guide 204 reaches the outlet roller 203. The outlet roller 203 
is made of the same material as the inlet roller 201 and insures the 
transport of the paper sheet to the following transport path. In FIG. 12, 
a case 219, a pressing member 220 and the compression spring 218 cooperate 
to press the ball 215 in the vertical transport path. The rotation speed 
V.sub.1 of the inlet roller 201 is nearly equal to the rotation speed 
V.sub.2 of the skew rollers 202 which is in turn lower than the rotation 
speed V.sub.3 of the outlet roller 203. It is to be noted that since the 
rotation speed V.sub.2 of the skew roller 202 is a downward transport 
component, it is selected to be V.sub.2a .times.cos .theta.. In an 
illustrative embodiment, the speed V.sub.2 is V.sub.3 cos .theta. because 
V.sub.2a is equal to V.sub.3. Further, the transporting force F.sub.1 of 
the inlet roller 201 is greater than the transporting force F.sub.2 of the 
skew rollers 202 which is in turn nearly equal to the transporting force 
F.sub.3 of the outlet roller 203. Providing only the inlet roller 201 with 
such a great transporting force F.sub.1 is advantageous in that after the 
leading edge of a paper sheet has reached the skew rollers 202, the sheet 
is prevented from being driven askew until the leading edge thereof moves 
away from the inlet roller 201, whereby the skew timing is maintained 
constant. The transporting force F.sub.3 of the outlet roller 203 which is 
selected to be equal to the transporting force F.sub.2 of the skew rollers 
202 insures some margin regarding the skew transport distance. 
FIG. 13 shows a drive system associated with the skew section 200. In FIGS. 
11 and 13, a driving force is applied to a timing pulley 210 which is 
affixed to the shaft of the outlet roller 203. The timing pulley 210 
transmits the driving force to the inlet roller 201 via a timing pulley 
206 and a double-tooth timing belt 213. The timing pulley 206 is rigidly 
mounted on the shaft of the inlet roller 201. FIG. 14 shows a drive 
transmitting portion in an enlarged front view. As shown in FIGS. 11 and 
14, since each skew roller 202 has to have the shaft thereof inclined, it 
is driven by the timing belt 213 via an idler 208 which has a helical gear 
208a and a timing pulley 208a. FIG. 15 shows the skew motion of a copy 
sheet schematically. As shown, a paper sheet P begins moving askew as soon 
as its trailing edge moves away from the inlet roller 201, ends the skew 
motion when its end abuts against the reference guide 204, and then moves 
straight ahead under the action of the outlet roller 203. 
The reference guide 204 is shown in a fragmentary section in FIG. 16. In 
the illustrative embodiment, the reference guide 201 is fastened by screws 
to a drive guide 205 which faces a driven guide 217. 
The paper sheet moved away from the skew section 200 is guided by the 
transport guide 308 and driven guides 309 and 310 and driven by the 
transport roller 301 and driven rollers 305 and 306 to the deflecting 
section B. The deflecting section B has the discharge roller 304, driven 
roller 307, driven guide plate 311, and pawls 312. The pawls 312 each is 
actuated by a solenoid, i.e., it is opened or closed by a solenoid on the 
basis of a designated mode to stack copy sheets in the associated bin 350. 
The jogging unit will be described with reference to FIGS. 17 to 19. As 
shown, a bin fence 450 extends upright from one side edge of each bin 350 
while an upright wall 508 extends from another side edge of the bin 350 
which is perpendicular to the edge where the bin fence 450 is positioned. 
An elongated slot 511 is formed through the bin 350 in close proximity to 
the edge opposite to the edge where the bin fence 450 is positioned. As 
shown in FIG. 18, the elongated slot 511 extends toward the bin fence 450 
over a predetermined distance. The distance a of the slot 511 to the 
upright wall 508 is smaller than the sum of the distance b between the bin 
fence 450 and the upright wall 508 and the width c of the fin fence 450. 
In the illustrative embodiment, the distance a lies in the range of 125 to 
140 millimeters which was found to be favorable by experiments. 
Specifically, should the dimension a be smaller than 124 millimeters, a 
moment would act on a paper sheet P of relatively large format such as A3, 
as shown in FIG. 20. Conversely, should the dimension a be greater than 
140 millimeters, a moment would act on a paper sheet P of relatively small 
format such as B5 and fed in a laterally long position, as shown in FIG. 
21. Such moments prevented paper sheets from being positioned in an 
expected manner. 
In FIGS. 17 to 19, the shaft jogger 502 extends upright throughout the 
slots 511 of the individual bins 350 and functions to position paper 
sheets by abutting against their edge. The jogger shaft 502 is provided 
with a high friction surface by rubber, sponge, sand paper, sand blasing 
or similar technology, as will be described. As shown in FIG. 19, the 
jogger shaft 502 is constantly biased by leaf springs 503a and 503b so as 
to free a paper stack from excessive forces, free individual copy sheets 
from scratches and creases, and free the motor from overloads. FIGS. 22 to 
25 each show a specific implementation for providing the shaft 502 with a 
high friction surface. In FIG. 22, rubber, cork, sponge or sandpaper 
serving as a high friction membeer H is adhered to at least a part of the 
surface of the shaft 502 which contacts copy sheets. In FIG. 23A, the high 
friction member H is implemented as horizontally projecting bristles 
while, in FIG. 23A, it is implemented as downwardly projecting bristles. 
In FIG. 24, the surface of the shaft 502 is treated by sand blasting to 
implement the high friction member H. Further, in FIG. 25, the high 
friction member H comprises powder or particles deposited on the surface 
of the shaft 502. 
FIG. 26 shows the interaction of the jogger 502 and the copy sheet P. As 
the shaft 502 moves to shift the paper sheet P from a position (1) toward 
a position (2), the high friction member H causes the sheet P to move in a 
direction X without slipping on the shaft 502 even through the sheet P may 
have been curled. The paper sheet P, therefore, surely reaches the bin 
fence 450 and is positioned by the latter with accuracy. To further 
promote accurate positioning of the paper sheet P, an arrangement may be 
made such that the shaft 502 moves downward while urging the sheet P in 
the direction X. This will be successful in correcting the deformation 
(curl) of the paper sheet P forcibly. In such a configuration, the shaft 
502 may be provided with a member rotatable up and down to press a curled 
portion of the paper sheet. 
As shown in FIGS. 17 and 19, the upper and lower ends of the jogger shaft 
502 are nested in recesses of holders 504a and 504b, respectively. Timing 
belts 507a and 507b are respectively located above and below the bins 350 
and extend in substantially the same direction as the slots 511 of the 
bins 350. Lugs provided on the holders 504a and 504b are respectively 
mated with recesses formed in the timing belts 507a and 507b, whereby the 
holders 504a and 504b are affixed to the associated timing belts 507a and 
507b. Among pulleys 509, 510, 516 and 512 over which the timing belts 507a 
and 507b are passed, the pulleys 509 and 516 are respectively affixed to 
opposite ends of a vertically extending drive shaft 514. The lower timing 
belt 507b is passed over a pulley 512 which is rigidly mounted on the 
output shaft of a size shift motor 515. The displacement of the jogger 
shaft 502 based on size is supervised in terms of the number of pulses to 
be applied to the size shift motor 515. 
Specifically, for a certain paper size, the size shift motor 515 drives the 
jogger shaft 502 to a position spaced apart by a predetermined distance 
from a paper sheet which will arrive (in the embodiment, 10 millimeters; 
hereinafter referred to as a first stop position). As soon as such a paper 
sheet fully enters the bin 350 and drops onto the upright wall 508, the 
jogger shaft 502 is moved toward the sheet and then brought to a stop when 
moved beyond the edge of the sheet by a predetermined amount (in the 
embodiment, 5 millimeters; hereinafter referred to as a second stop 
position). When the shaft 502 is to be returned after positioning a copy 
sheet, it may be once brought to a stop at the width corresponding to the 
paper size (hereinafter referred to a third position) and then moved to 
its original position. Alternatively, the moving speed of the shaft 502 
may be varied during the course of the return. This is to prevent the copy 
sheet once positioned on the bin 350 from moving away from the bin fence 
450 due to its own elasticity. In the illustrative embodiment, the jogger 
shaft 502 moves from the second stop position to the third stop position 
at a speed lower than a speed at which the paper sheet urged against the 
bin fence 450 springs back due to the elasticity thereof. As a result, the 
position of the paper sheet on the bin 350 is prevented from being 
disturbed due to spring-back or similar cause. 
A reflection type sensor, not shown, is mounted on the holder 504a in a 
position closer to the bin fence 250 than to the shaft 502. After the 
jogger shaft 502 has positioned the first copy sheet on the bin 350, it is 
moved by the size shift motor 515 with the above-mentioned sensor 
searching for the edge of the copy sheet. Since the size shift motor 515 
is implemented with a stepping motor, it is possible to find the position 
of the edge of the copy sheet by counting pulses from the instant when the 
motor 515 has begun to rotate to the instant when the sensor turns on. 
Hence, the third position of the jogger shaft 502 can be determined 
accurately even if the paper size is irregular (in the range of 1 to 2 
millimeters). Alternatively, the third position may be simply calculated 
by use of a paper size signal transmitted from the copier body so as to 
move the shaft 502 accordingly. 
While the paper positioning arrangement has been shown and described in 
relation to the bin 350, it is similarly applicable to a conventional tray 
to be loaded with copy sheets. A paper stack is urged against the bin 
fence 450 and thereby positioned at one edge thereof. Regarding another 
edge perpendicular to that edge, the paper stack is abutted against the 
upright wall 508 which is perpendicular to the bin fence 450, by using the 
inclination of the bin 350. 
Each bin 350 is provided with various kinds of devices for promoting 
accurate and efficient paper positioning and stapling, as follows. 
FIG. 27 shows the bin 350 in a position mounted on the sorter. As shown, 
the bin 350 has a main angular portion 401 and auxiliary angular portions 
402 and 403 which are smaller in inclination than the main angular portion 
401. When the main angular portion 401 is provided with a certain angle 
(in the illustrative embodiment, 30 degrees), a paper stack begins to bend 
as the number of paper sheets increases. This is especially true when the 
individual paper sheets are thin (see portion A, FIG. 28). To prevent 
this, the auxiliary angular portion 403 bears a part of the weight of the 
paper stack. In this embodiment, the angle of the auxiliary angular 
portion 403 is selected to be 15 degrees. However, should the main angular 
portion 401 be excessively short and the auxiliary angular portion 403 be 
excessively long, the auxiliary portion 403 would bear an excessive part 
of the weight of the paper stack to thereby prevent the stack from falling 
along the bin 350. Preferably, the main angular portion and the auxiliary 
angular portion are dimensioned about 300 millimeters and about 80 
millimeters, respectively. 
The auxiliary angular portion 402 is a countermeasure against face curl. 
FIG. 29 shows a bin 350 without the auxiliary angular portion 402 and 
paper sheets with face curl stack on such a bin 350, while FIG. 30 shows a 
bin 350 with the auxiliary angular portion 402 and paper sheets with face 
curl stacked thereon. In FIG. 29, the paper stack P is spaced apart from 
the bin 350 in a portion c while, in FIG. 30, the clearance between the 
paper stack P and the bin 350 is not noticeable in a portion d. This 
indicates that the configuration shown in FIG. 30 allows a greater number 
of paper sheets with face curl to be stacked together than the 
configuration shown in FIG. 29. In the illustrative embodiment, the 
auxiliary angular portion 402 has an angle of 15 degrees and a length of 
about 20 millimeters. 
Referring to FIGS. 31 and 32, a projection 411 extends downward from the 
underside of the bin 350 for the purpose of pressing the curl of a paper 
sheet. Although a paper sheet driven out onto the bin 350 is positioned in 
one direction, it is apt to get over the fence 450 when its curl is great. 
The projection 411 presses such a curl of the paper sheet to promote 
accurate positioning. FIGS. 33 and 34 show a bin 350 with the projection 
411 and a bin 350 without the projection 411, respectively. In FIGS. 33 
and 34, a paper sheet sequentially assumes positions (1), (2) and (3). In 
FIG. 32, the reference numerals 412, 413 and 414 designate projections for 
fixing the bin 350 in place. 
FIG. 35 shows the bin 350 in a mounted position. In the figure, there are 
shown side panels 430a and 430b and bin supports 431a and 431b. The bin 
350 is fixed in place by the bin support 430a located at the bin fence 
side F and is simply held on the other bin support 431b while being 
slightly spaced apart from the latter. Fixing the bin 350 at the bin fence 
side F maintains the stapling position constant. The small clearance 
between the bin 350 and the bin support 431b successfuly absorbs thermal 
expansion of the bin 350. 
As shown in FIG. 32, the bin 350 is provided with a bin rib 415a for 
allowing a paper sheet to fall smoothly. Bin ribs 415b, 415c and 415e also 
provided on the bin 350 are higher than the other ribs in their portions 
close to the notch which is adapted to take out a paper stack, whereby a 
paper stack is prevented from bending when loaded on the bin 350. The bend 
of a paper stack would obstruct smooth fall of the stack. When a paper 
sheet is positioned by the jogger shaft 502 in a bent position, it often 
fails to be positioned with accuracy since it lacks elasticity. Ribs 415f 
are so configured as to prevent a paper sheet from entering the slot 511. 
Specifically, as shown in FIG. 36, the ribs 415f each protrudes upward 
and downward in the vicinity of the slot 511 to prevent a paper sheet from 
entering the sot 511 and to prevent it from entering the not of the 
overlying bin. The ribs 415f are arranged in a position substantially 10 
millimeters inward of the edge of the paper size so as to surely guide the 
edges of those paper sheets which are apt to enter the slot 511. Each rib 
415f extending upward from the bin 350 has a triangular configuration 
which is less inclined at one side than at the other side. With such a 
configuration, the ribs 415f guide a stapled paper stack P so that the 
latter may be discharged without being caught by the former. As shown in 
FIG. 37, the ribs 415f each is configured as comparatively low ribs 415f 
and 415h in the vicinity of the upright wall 508 of the bin 350, FIG. 31, 
and is sequentially increased in height toward the slot 511 for the 
purpose of accommodating a greater number of paper sheets. Bin ribs 415g 
are aligned with the ribs 415f and adapted to promote smooth fall of paper 
sheets. 
In FIG. 32, the bin 350 is formed with a notch 416 to allow the chuck 
section to chuck a stack of paper sheets positioned on the bin 350. A 
portion 417 of the bin 350 is positioned at a lower level than the other 
part of the bin 350, as best shown in FIG. 38. This portion 417 
facilitates the removal of a paper stack of relatively small size. Should 
the notch 422 be extended deeper into the bin 350 in order to omit the 
portion 417, the mechanical strength of the bin 350 would be critically 
lowered. In FIG. 32, the reference numeral 418 designates notches for 
accommodating a discharge roller. 
FIG. 39 shows a positional relation between the discharge roller 304 and 
the upright wall 508 of the bin 350. The angle a shown in the figure is 
slightly greater than 90 degrees. A portion b is straight while a portion 
c is curved. The dicharge roller 304 protrudes beyond the portion c in the 
paper discharging direction. The configuration of the upright wall 508 
shown in FIG. 39 is effective regarding the positioning accuracy when 
paper sheets have face curl. However, when more than a certain number of 
paper sheets with face curl are stacked on the bin 350, the stack P 
becomes higher than the upright wall 508 with the result that an upper 
part thereof rides on the wall 508, as indicated by X in FIG. 40. In the 
illustrative embodiment, the unique configuration of the wall 508 and the 
unique position of the discharge roller 304 mentioned above are combined 
to enhance accurate positioning of paper sheets with face curl. In 
addition, the discharge roller 304 urges the paper sheets downward to 
eliminate the occurrence shown in FIG. 40. A rib 419 shown in FIG. 31 and 
a rib 421 shown in FIG. 32 reinforce the bin 350. 
FIGS. 41 and 42 show a positioning roller assembly 550 which promotes more 
accurate paper positioning with no regard to the kind of paper sheets. As 
shown, the assembly 550 has a positioning roller 333 mounted on a driven 
shaft 332 which is in turn retained by a roller holder 331. The roller 
holder 331 is mounted on a shaft 340 together with the discharge roller 
304. A drive pulley 334 is affixed to the discharge roller 304. The 
positioning roller 333 is driven by the drive pulley 334 in interlocked 
relation to a driven pulley 335 affixed to the driven shaft 332 by a belt 
336. The drive pulley 334 and driven pulley 335 have an inclination of 
about 10 degrees. The positioning roller 333 shifts a paper sheet 
obliquely and thereby positions it against both of the bin fence 450 and 
upright wall 508. 
FIG. 43 indicates a positional relation between the positioning roller 333 
and a paper sheet P. A paper sheet P transported by the discharge roller 
304 and driven roller 307 is fed into the bin 350 through the associated 
pawl 312. At this instant, the positioning roller 333 is spaced apart from 
the bin 350 by 5 to 7 millimeters, so that the paper sheet P moves above 
the roller 333 into the bin 350 (position (1)). The rear edge of the paper 
sheet P jumps out over the upright wall 508 by 20 to 30 millimeters due to 
the speed at which the sheet P is driven into the bin 350. The center of 
the positioning roller 333 is spaced apart by about 15 millimeters from 
the upright wall 508 and by about 20 millimeters from the bin fence 450. A 
paper sheet P dropped on the positioning roller 333 is forced to drop by 
the roller 333 onto the bin 350. The paper sheet P thus laid flat on the 
bin 350 by the roller 333 is shifted toward the wall 508 due to the 
inclination of the bin 350 and, as a result, gets under the roller 333 
(position (2)). Thereafter, when the rear edge of the paper sheet P 
contacts or is about to contact the wall 508, the jogger shaft 502 is 
moved to cause the sheet P into abutment against the bin fence 450, as 
stated earlier. Subsequently, as shown in FIG. 44, a solenoid 342 is 
energized to raise a bracket 337. As a result, a pin 339 received in a 
hole 338, FIG. 41, is raised to cause the roller holder 331 to rotate 
counterclockwise about the shaft 340, whereby the positioning roller 333 
is let fall onto the bin 350. In this condition, the roller 333 in 
rotation urges the paper sheet P against the wall 508 and bin fence 450. 
The movement of the shaft 502 and that of the positioning roller 333 
described above are completed before the next paper sheet arrives at the 
bin 350 or before it reaches the position between the roller 33 and the 
bin 350. The second and successive paper sheets are positioned in the same 
manner as the first sheet. If the force exerted by the positioning roller 
33 on a paper sheet P for the positioning purpose is excessively great, 
the paper sheet will be bent, as shown in FIG. 45. In the light of this, 
the transporting force of the positioning roller 333 is selected such that 
the roller 333 transports a single paper sheet P and, on abutment of the 
sheet P against the bin fence 450 and wall 508, simply slips on the sheet 
P. Specifically, as shown in FIG. 46, the positioning roller 333 has a 
high friction member 333b which protrudes from a part of a low friction 
member 333a. Alternatively, a plurality of high friction members 333b may 
be provided on the positioning roller 333, as shown in FIG. 47 or 48. If 
desired, a member having an adequate degree of friction may be provided on 
the positioning roller 333 in order to achieve the same advantage. 
A stack of paper sheets positioned by the above sequence of steps is 
stapled or otherwise finished and then taken out in a direction indicated 
by an arrow x in FIG. 18. The removal of the finished paper stack is easy 
because no obstruction exists in the direction x. 
Referring to FIGS. 49, 50 and 51, the stapler device 700 located at one 
side of the bins 350 has a flat bracket 703 which is loaded with the 
stapler 701 and paper pulling device 615. The stapler 701 sequentially 
drives staples into paper sheets distributed to and stacked on the 
individual bins, while the paper pulling device 615 chucks such paper 
stacks one at a time and carries them substantially in the horizontal 
direction. One end of the bracket 703 is bent upward, and a bracket 703a 
is affixed to that end of the bracket 703. A bearing 704 shown in FIGS. 50 
and 51 is mounted on the bracket 703a and affixed to the latter by a stop 
ring 705. A shaft 710 is retained by holders 708 and 709 which are mounted 
on a base 706 and an upper panel 707, respectively. The bearing 704 is 
slidably coupled over the shaft 710. Rollers 714 and 715 are respectively 
mounted on shafts 712 and 713 which are in turn mounted on the bracket 
711. The rollers 714 and 715 hold a bracket 716 therebetween. 
A drive belt 717 extends upward and substantially parallel to the side 
edges of the bins 350. The drive belt 717 is held between and fastened to 
the bracket 703a and a bracket 718 by screws and is passed over pulleys 
719a and 719b which are spaced apart by a predetermined distance in the 
vertical direction. The rotation of a drive motor 720 is transmitted to a 
pulley 723 by a pulley 721 mounted on the output shaft of the motor 720 
and a belt 722. A drive gear 724 is mounted on the same shaft as the 
pulley 723 while a gear 725 is held in mesh with the drive gear 724. 
Hence, the rotation of the pulley 723 is transmitted to the drive pulley 
719a by way of the drive gear 724 and gear 725. The drive pulley 719a is 
mounted on one end of a shaft 726. By such a gearing, the drive belt 717 
is driven in a rotary motion to move the stapler 701 and paper pulling 
device 615 up and down. A position sensor 727 is provided on the bracket 
711 in such a manner as to hold it therebetween. The bracket 716 has holes 
716a at equally spaced positions thereof which correspond to the bins 350. 
This position sensing mechanism causes the stapler 701 and paper pulling 
device 615 to be so controlled as to stop at the positions where the 
individual bins 350 are located. Further, a lug 728 and a sensor 729, FIG. 
49, cooperate to define the upper limit position of the bracket 703. 
Specifically, when the lug 728 enters the sensor 729, the motor 720 is 
deenergized. 
The operations of the stapler device 700 will be better understood with 
reference to FIG. 52 which schematically shows a paper sheet P laid on the 
bin 350, the chuck section 620, and stapler 701. Specifically, the paper 
sheet P just entered the bin 350 is located in a position 730d and then 
brought into abutment against the bin 450 by the previously stated jogging 
device. After the copying operation has been completed, the chuck section 
620 advances from a position 620b to a position 620c both of which are 
indicated by dash-and-dot lines in the figure. At the position 620c, the 
chuck section 620 closes to chuck the paper stack P and then stops at a 
position 620a as indicated by a solid line in the figure. As a result, the 
paper stack is shifted to a position 730f and stapled by the stapler 701 
on the bin 350. Thereafter, the stapled paper stack P is returned to a 
position 730e by a sequence of steps opposite to the above-stated 
sequence. Then, the stapler unit 700 is moved to the next bin 350 to 
repeat such a stapling operation. The stapling operation outlined above 
will be described in detail later. 
Referring to FIGS. 53 to 56, the paper pulling device 615 has a chuck 
section 620 and a mechanism 640 for causing the chuck section 620 to move 
back and forth substantially in the horizontal direction. The chuck 
section 620 has an upper and a lower lever 622 and 624 which are rotatably 
mounted on a base plate 621. A solenoid 626 actuates the upper and lower 
levers 622 and 624 to cause an upper and a lower chuck 623 and 625 to 
chuck a paper stack P. 
The reciprocating mechanism 640 has a frame 641 and a shaft 642 on and 
along which the chuck section 620 is slidable. Specifically, a bearing 629 
carries the base plate 621 therewith and is slidably mounted on the shaft 
642. A timing belt 643 is provided on the frame 641 for moving the chuck 
section 620 toward and away from the paper stack P. The chuck section 620 
and timing belt 643 are affixed to an arm 621a extending out from the base 
plate 621. The timing belt 643 is passed over pulleys 644 and 645. The 
pulley 644 is mounted on the output shaft of a stepping motor 646. In this 
condition, the pulley 644 is rotated by the output of the stepping motor 
646 to in turn move the timing belt 643. Then, the timing belt 643 causes 
the chuck section 620 affixed thereby through the arm 621a to move in a 
reciprocating motion. A position sensor 650 is provided on the frame 641 
while a plate 630 is provided on the base plate 621 to be sensed by the 
sensor 650. The position sensor 650 is responsive to the home position of 
the chuck section 620. It is to be noted that the home position of the 
chuck section 620 intervenes between a chucking position on the bin 350 
and a stapling position. 
In operation, on the start of a staple mode operation, the drive belt 717, 
FIG. 49, moves the stapler 701 and paper pulling device 615 up or down. 
Specifically, as shown in FIG. 53, the stapler 701 and paper pulling 
device 615 are moved toward one of the bins 350 which is loaded with a 
paper stack P to be stapled. The stapler 701 and paper pulling device 615 
are brought to a stop in the vicinity of the bin 350 of interest on the 
basis of the output of the position sensor 727, FIG. 49. At this instant, 
the solenoid 626 is not energized so that the rotatable levers 622 and 624 
and, therefore, the chucks 623 and 625 are held in their open position. 
Thereafter, the stepping motor 646 is rotated by a predetermined amount to 
move the timing belt 643 and to thereby move the chuck section 620 toward 
the paper stack P. The moving speed of the chuck section 620 is controlled 
by varying the rotation speed of the stepping motor 646. In the 
illustrative embodiment, when the chuck section 620 having chucked the 
paper stack P returns to the stapling position, it is sequentially 
accelerated at the beginning of such a movement and then sequentially 
decelerated at the end of the same in order to prevent the accurately 
position paper stack P from being distrubed due to inertia. In this 
embodiment, the chuck section 620 is accelerated and decelerated on a 
nearly constant acceleration basis since the maximum inertia of a constant 
acceleration motion is smallest. 
As soon as the chucks 623 and 625 reach a position where they can chuck the 
paper stack P (FIG. 55), they are stopped there and, at the same time, the 
solenoid 626 is energized. As a result, the chucks 623 and 625 are closed 
(FIG. 54) to chuck an edge portion of the paper stack P. More 
specifically, when the sloenoid 626 is turned on, a spring 627 anchored to 
the solenoid 626 pulls a lever 628 to which the upper lever 622 is 
connected. As a result, the upper lever 622 is rotated counterclockwise 
about a fulcrum 622a to in turn lower the upper chuck 623. The lower lever 
624 contacts the upper lever 622 at a potion 624c thereof, so that the 
movement of the upper lever 622 is transmitted to the lower lever 624. The 
lower lever 624 is, therefore, rotated clockwise about a shaft 624a to 
raise the lower chuck 625. Consequently, the upper and lower chucks 623 
and 625 chuck the paper stack P. The displacement of each of the chucks 
623 and 625 is determined by the distances between the fulcrum of rotation 
of the lever 628 and the points of force and action. In the illustrative 
embodiment, as shown in FIG. 54, the upper chuck 623 is assumed to have a 
fulcrum 622a which is spaced apart by 92 millimeters from a point of 
action 622b and by 33 millimeters from a point of force 622c. Hence, the 
displacement of the chuck 623 is 92:33 which is nearly equal to 2.79:1 in 
terms of ratio. Regarding the lower chuck 625, the shaft 624a is assumed 
to be spaced apart by 26 millimeters from a point of action 624b and by 33 
millimeters from a point of force 624c, so that the displacement is 26:33 
which is nearly equal to 0.79:1 in terms of ratio. More specifically, when 
the upper chuck 623 moves downward by 3.5, the lower chuck 623 moves 
upward by 1. Further, the chucking force of the chucks 623 and 625 is 
determined by the force of the spring 627 anchored to the solenoid 626. As 
the number of paper sheets P to be chucked by the chucks 623 and 625 
increases, the spring 627 becomes longer and, therefore, the chucking 
force becomes stronger. This frees the paper sheets P from dislocation 
ascribable to weak chucking force. 
When the chucks 623 and 625 are constructed to grip one point of the paper 
stack P adjacent to a corner, a moment acts on the paper stack P due to 
inertia in the event when the paper stack P is pulled, as shown in FIG. 
57. Then, the paper stack P will be shifted askew on the bin 350 and 
thereby stapled in an unexpected position. To eliminate this problem, as 
shown in FIG. 58, the chucks 623 and 625 may each be bifurcated or 
otherwise configured to grip the paper stack P at a plurality of points of 
the latter. 
Subsequently, the stepping motor 646 is reversed to cause the chuck section 
620 to return to the original position while carrying the paper stack P 
therewith, as shown in FIG. 56. As a result, the paper stack P is shifted 
in the substantially horizontal direction toward the stapler 701. As soon 
as an edge portion of the paper stack reaches a position where it can be 
stapled, the chuck section 620 is brought to a halt. Thereafter, the 
stapler 701 is actuated to drive a staple into the edge portion of the 
paper stack P. 
On completion of the stapling operation, the stepping motor 646 is rotated 
in the forward direction to advance the chuck 620 away from the stapler 
701. After the chuck section 620 has returned the paper stack P to the bin 
350, the solenoid 626 is deenergized with the result that the upper and 
lower chucks 623 and 625 are opened. The stepping motor 646 is reversed 
again to move the chuck section 620 back to the predetermined position. 
Then, the stapler 701 and paper pulling device 615 are moved downward 
toward the next bin for repeating the above stapling operation there. 
Referring to FIGS. 59 to 61, the paper positioning mechanism will be 
described more specifically. As shown in FIG. 59, the bin fence 450 
extends upward from the edge of the bin 350 which is adjacent to the 
stapler 701. The bin fence 450 is rotatably mounted on a shaft 451 which 
extends along the underside of the bin 350. Hence, the bin fence 450 is 
tiltable to an open position, as shown in FIG. 60. The shaft 451 is 
journalled to the bin 350 by bearing portions 456 which extend downward 
from opposite edge portions of the bins 350. A helical spring 452 is wound 
round the shaft 451 and anchored at opposite ends thereof to the back of 
the bin fence 450 and the underside of the bin 350. In this configuration, 
the bin fence 450 is constantly biased by the spring 452 to the upright 
position thereof. 
The bin fence 450 is openable in interlocked relation to the upward and 
downward movement of the stapler 701. A fence rotating plate 453 provided 
on the shaft 451 and a fence releasing plate 454 provided on the stapler 
701 constitute members for so tilting the bin fence 450. The fence 
rotating plate 453 is partly received in a sectoral opening formed through 
one extension 450a of the bin fence. When the plate 453 is rotated 
downward, the lower edge of the sectoral opening of the bin fence 450 
abuts against the plate 453 with the result that the bin fence 450 is 
tilted along with the plate 453. When the plate 453 is rotated upward, it 
does not contact the bin fence 450 and is free to rotate. A roller 454a 
mounted on the fence releasing plate 454 protrudes to remain in contact 
with the fence rotating plate 453. When the stapler 701 is elevated or 
lowered, the roller 454a rotates the plate 453 in contact therewith. 
While a sorting operation is under way, the bin fence 450 is held in the 
upright position by the helical spring 452, as shown in FIG. 59. In this 
condition, the paper sheets P entering the bin 350 one after another are 
positioned with their edges abutting against the bin fence 450. When the 
sorting operation is completed, the stapler 701 begins to move downward 
with the result that the roller 454a provided on the stapler 701 contacts 
the fence rotating plate 453 of the bin 350 and urges the latter downward, 
as shown in FIG. 60. The plate 453 in turn causes the bin fence 450 to 
tilt against the action of the helical spring 452, whereby the bin fence 
450 is opened. At this instant, the bin fence 450 and plate 453 have been 
lowered beyond the major surface or plane A of the bin 350. In this 
condition, the previously stated stapling operation is effected. 
When the stapled sheet stack P is returned to the original position on the 
bin 350, the stapler 701 is lowered toward the next bin 350. As the fence 
releasing plate 454 is moved away from the fence rotating plate 453 due to 
the downward movement of the stapler 701, the bin fence 450 is raised to 
the original position by the spring 452. The movement of the bin 350 and 
the stapling operation described above occur in all of the bins 350 to 
which paper sheets P have been distributed. 
After all the paper stacks P have been stapled, the stapler 701 is elevated 
to the uppermost position, i.e. a home position which is higher in level 
than the first or uppermost bin 350. At this time, although the fence 
releasing plate 454 contacts the fence rotating plate 453 from below, the 
plate 453 simply idles upward without rotating the bin fence 450, as shown 
in FIG. 61. As soon as the plate 454 moves away from the plate 453 due to 
the elevation of the stapler 701, the plate 453 is returned to the 
position shown in FIG. 59 due to gravity. 
FIG. 62 shows a modification of the paper positioning mechanism described 
above. As shown, an elastic member 455 is affixed to the bin fence 450 for 
the purpose of receiving the fence rotating plate 453. When the plate 453 
is idly rotated upward by the returning stapler 701, it abuts against the 
elastic member 455. As a result, the plate 453 is returned to the original 
position by the elasticity of the member 455. 
Referring to FIGS. 63 to 66, another specific configuration of the bin 
fence 450 will be described. As shown in FIGS. 63 and 64, the bin fence 
will be described. As shown in FIGS. 63 and abuts against all of the bins 
350 for positioning paper sheets. Specifically, the fence 460 is rotatable 
about upper and lower fulcrums 460a and 460b and has a gear 460c at the 
lower fulcrum 460b. The gear 460c is in mesh with a gear 461 which is 
driven by a motor 462. To position paper sheets, the fence 460 is brought 
to the position shown in FIGS. 63 and 64 where it faces the bins 350. 
During a stapling operation which follows a sorting operation, the fence 
450 is rotated by 90 degrees from the position of FIGS. 63 and 64 to the 
position of FIGS. 65 and 66. In such a position, a paper stack P can be 
shifted to the stapling position. 
FIG. 67 shows a control system applicable to the illustrative embodiment. 
As shown, the control system is implemented as a microcomputer control 
system having a CPU 800, a ROM 801, a RAM 802, I/O ports 803 and 806, a 
clock timer controller (CTC) 804, and a universal asynchronous receiver 
transceiver (UART) 805. By using a program stored in the ROM 801 and RAM 
802, the CPU 800 receives output signals of sensor switches (SW) via the 
I/O port 806 and controls various loads via various drivers 808, 809, 810, 
811 and 812, a phase signal generator 813 and a SSR 807 in response to the 
outputs of the I/O port 803 and CTC 804. The control system is connected 
to the copier by an optical fiber, not shown, via the driver 815 and UART 
805 so as to interchange various status and command signals. 
Specifically, the sensors and switches (input system) include the inlet 
sensor 314, outlet sensor 115, bin sensors 321 and 323, discharge sensors 
322 and 324, pulse generator 315, cover SW, DIPSW, size home sensor 501, 
elevation home sensor 729, elevation position sensor 727, chuck home 
sensor 650, stylus sensor, paper sensor 675, and staple home sensor. The 
loads (output system) include the sorter motor (AC motor) 313, switching 
SOL 107, deflecting SOLs, chuck SOLs 626, positioning SOLs 342, proof 
motor (DC motor) 117, staple motor (DC motor), size shift motor (stepping 
motor) 515, elevation motor (stepping motor), an chuck motor (stepping 
motor) 646. 
Among the signals interchanged between the control system and the copier, 
signals sent from the copier and meant for the stapler unit 700 include a 
sorter start signal, copier paper discharge signal, staple end signal, 
system reset signal, service call reset signal (S. C reset), status 
request signal, mode signal, size signal, and bin designate signal. 
Signals sent from the stapler 700 to the copier include a type 
identification signal, paper-on-tray signal, stack over signal, bin over 
signal, cover open signal, no stylus signal, JAM signal, staple inhibit 
signal, paper discharge signal, WAIT signal, BUSY signal, end-of-mode 
signal, staple count signal, and error signal. 
FIGS. 68A and 68B are flowcharts demonstrating the overall operation of the 
illustrative embodiment. As shown, the control system receives a mode 
signal from the copier (step S1-1). After the start of a copying 
operation, the system receives a size signal (S1-2) and then a sorter 
start signal (S1-3). In response, either the sort motor (for sorting or 
stacking) or the proof motor (for proof or interrupt) is turned on as 
indicated by the mode signal. The proof mode (S1-4) will be described 
first. 
After the proof motor 117, FIG. 5, has been turned on (S1-5), the switching 
SOL 107, FIG. 7, is energized (S1-6). On receiving a paper discharge 
signal (S1-7), the control system steers a paper sheet coming in through 
the inlet guide 102 (S1-8) toward the proof tray 116 (S1-9). After the 
discharge of the paper sheet onto the proof tray 116, a paper discharge 
signal is sent to the copier (S1-10) to inform the copier of the discharge 
of the received paper sheet. The steps described so far are repeated until 
the copying operation ends (S1-11). Of course, the control system is 
performing jam detection, although not shown. When the copying operation 
is completed, the switching SOL 107 and proof motor 117 are turned off 
(S1-12). Then, the system awaits the next copying operation. 
The sort or stack mode operation is as follows. After the sorter motor 313, 
FIG. 5, has been turned on (S1-13), whether or not jogging is allowable is 
determined on the basis of the size signal, for example. If the answer of 
the decision is positive (YES) (S1-14), the jogger shaft 502 is shifted to 
a position matching the size signal (S1-15). When the copier drives a 
paper sheet thereoutof, it sends a bin designate signal and a discharge 
signal to the control system (S1-16). A bin 350 of interest is decided on 
the reception of the discharge signal (S1-17). Then, a paper sheet from 
the copier enters the sorter (S1-18). On the turn-on of the inlet sensor 
314, a deflecting solenoid (SOL) designated by the bin designate signal is 
turned on (S1-19), whereby the paper sheet is steered to the bin 350 of 
interest. 
When the paper sheet is driven out onto the designated bin 350 (S1-20), a 
paper discharge signal is sent to the copier (S1-21) to report that the 
paper sheet has been surely discharged onto the bin 350. In response, the 
copier determines the next destination, the destination after jam 
recovery, etc. When a suitable period of time necessary for the paper 
sheet to be settled on the bin 350 (e.g. 300 milliseconds; step 1-22), the 
size shift motor 515, FIG. 17, is turned on to shift the jogger shaft 502 
(S1-23) so as to position the paper sheet in the direction (lateral) 
perpendicular to the paper discharge direction. It is to be noted that the 
shaft 502 is shifted at a particular timing which is based on the 
discharge of the trailing edge of a copy sheet as sensed by the sensors 
322 and 324 (S1-24). 
It sometimes occurs that after the positioning operation a paper sheet 
fails to reach the end of the bin 350 or to the bin fence 450 due to curl, 
scratch or fold on the paper surface and/or substantial static 
electricity. In light of this, the positioning solenoid 342 is turned on 
(S1-25) simultaneously with the shift of the jogger shaft 502. As a 
result, the positioning roller 333 in rotation is brought into contact 
with the upper surface of the paper sheet to press the curl and urge it to 
the end portion (predetermined period of time=200 milliseconds; S1-26). 
The positioning roller 333 is associated with all of the bins 350, and all 
the positioning rollers 333 are lowered at the same time by the 
positioning SOL 342. Thereafter, the positioning SOL 342 is deenergized 
(S1-27). 
The above sequence is executed every time a paper sheet is discharged so as 
to position it (sorting or stacking) (S1-28). As the sorting or stacking 
operation ends, the sorter motor 313 is turned off (S1-29) and stapling is 
effected. In response to a staple start signal (S1-30), the stapler unit 
700 is actuated (S1-31) to staple a stack of paper sheets. On completion 
of the stapling operation (S1-32), the stapler device 700 and jogger shaft 
502 are returned to their home positions (S1-33). 
The paper positioning operation and the movement of the jogger shaft 502 
will be described with reference to FIGS. 69 and 70. The jogger shaft 502 
is held in a halt beforehand in a particular position matching the size 
signal (in the embodiment, a position about 10 millimeters spaced apart 
from the edge of a paper sheet which will be discharged), as stated 
earlier. Any suitable position may be selected so long as it prevents the 
shaft 502 from catching a paper sheet P and thereby causing it to jam or 
fold itself (FIG. 70(a)). On the lapse of about 300 milliseconds after the 
discharge of a paper sheet onto the bin 350, the jogging operation occurs. 
First, a phase signal in the form of pulses the number of which is 
associated with a displacement of 25 millimeters is fed from the I/O port 
803 to the constant voltage driver 811. As a result, the size shift motor 
(stepping motor) 515 is rotated counterclockwise to move the jogger shaft 
502 by about 25 millimeters toward the paper sheet (S2-1; FIG. 70(b)). The 
moving speed of the shaft 502 may be, but not limited to, about 500 pps. 
The gist is that the moving speed does not crease, scratch or fold the 
paper sheet P. Consequently, the paper sheet on the bin 350 is shifted by 
an extra amount of about 5 millimeters and thereby urged against the bin 
fence 450. If desired, an extra amount of feed other than 5 millimeters 
may be selected if it is capable of coping with irregular lengths of paper 
sheets P and implementing sure positioning. 
After urging the paper sheet P against the bin fence 450, the shaft 502 is 
once brought to a halt (in the embodiment 50 milliseconds); S2-2). This 
step is not essential, however, since it is simply to switch the rotating 
direction of the size shift motor 515. Thereafter, the motor 515 is 
rotated clockwise by the number of pulses associated with a displacement 
of 5 millimeters, so that the shaft 502 may move 5 millimeters away from 
the paper sheet (S2-3); FIG. 70(c)). At this time, the moving speed of the 
shaft 502 is selected to be about 300 pps. Nevertheless, any other speed 
may be selected so long as it is lower than the speed at which the paper 
sheet P springs back after the extra amount of feed, i.e., the position of 
the paper sheet P is not disturbed due to elasticity. Stopped after the 5 
millimeters return, the shaft 502 serves as a bin fence at the opposite 
side to the bin fence 450. This, coupled with the fact that the shaft 502 
remains in a halt for 50 milliseconds (S2-4), insures the position of the 
paper sheet P. Subsequently, the shaft 502 is returned to the initial 
position to prepare for the next paper sheet (S2-5; FIG. 70(d)) and 
stopped there (S2-6). At this time, the moving speed of the shaft 502 need 
only be the speed at which the shaft 502 will be in time for the discharge 
of the next paper sheet. In the case that complete positioning is not 
attainable (paper sheets with substantial curl), the entire or a part of 
the jogging operation may be effected a plurality of times with a single 
paper sheet. 
Assume that more than a predetermined number of paper sheets which can be 
stacked on the bin 350 (in the embodiment, thirty paper sheets) are driven 
out onto the bin 350. Then, stapling the discharged paper sheets is 
inhibited, and the shaft 502 is retracted to the home position without 
performing the jogging movement, as will be described with reference to 
FIG. 71. 
The number of paper sheets stacked on the bin 350 is detected by counting 
paper sheets (S3-2) which are sequentially discharged onto the first bin 
(S3-1). When it is decided that the number of paper sheets on the first 
bin has exceeded the number which can be stapled (S3-3), the shaft's 
jogging operation and the roller's positioning operation are interrupted 
(S3-4). Then, the shaft 502 is retracted to the home position (S3-5). 
Afterwards, the positioning operation is not performed with paper sheets 
which may be discharged. Stapling the paper sheets already stacked on the 
bin 350 is also inhibited (S3-6). 
The stapling operation will be described with reference to FIGS. 72A to 
72I. When paper sheets exist on the bins 350 after the sorting operation, 
the copier sends a staple start signal to the sorter. On receiving the 
staple start signal, the control system resets a sequence counter to 0 
(S4-1). The stapler device 700 located at the home position is moved to 
the first bin 350 whose paper stack is to be stapled (S4-2). After the 
stapler unit 700 has reached the first bin 350, the program is executed on 
the basis of the value of a staple sequence counter shown in FIG. 72A. On 
the arrival of the stapler device 700 at the first bin, the staple 
sequence counter is set from 0 to 1 (S4-3). 
When the value of the staple sequence counter is 1 (S4-4), the chuck motor 
(stepping motor) 646 is turned on (S4-5, FIG. 72B) to thereby move the 
chuck section 620, FIG. 53, forward. In this instance, the displacement is 
determined by the number of pulses (S4-6). By this displacement, chuck 620 
is moved from the home position to the position where it can chuck the 
paper stack. When the chuck section 620 is fully advanced (S4-7), the 
staple sequence counter is set to 2 , (S4-8). 
When the staple sequence counter is 2, the chuck SOL 626 is turned on 
(S4-9, FIG. 72C) to chuck the paper sheet. Then, the staple sequence 
counter is set to 3 (S4-10). 
When the staple sequence counter is 3, a timer is started (S4-11, FIG. 72D) 
to hold the state for 0.2 second. On the lapse of 0.2 second (S4-12), the 
timer is stopped (S4-13) and the staple sequence counter is set to 4 
(S4-14). This is successful in absorbing the response time of the chuck 
SOL 626 and insuring the chuck. 
When the staple sequence counter is 4, the chuck motor 646 is turned on 
(S4-15, FIG. 72E) to return the chuck 620 toward the home position. Then, 
the chuck home sensor 650 responsive to the arrival of the chuck section 
620 to the home position is turned on (S4-16), the chuck section 620 is 
brought to a stop at the home position, and the chuck motor 646 is turned 
off (S4-117). Subsequently, the staple sequence counter is set to 5 
(S4-18). At this instant, the chuck motor 646 is driven in a nearly 
constant acceleration motion. In the illustrative embodiment, the speed is 
increased from from 600 pps to 2000 pps in a slow-up mode. 
When the staple sequence counter is 5, the output of the paper sensor 675, 
FIG. 56, is checked (S4-19, FIG. 72F). If the answer of the step S4-19 is 
positive (YES), the staple motor is turned on (S4-20) to staple the paper 
stack. Whether or not the stapling action has completed is determined by 
referencing the output of the staple home sensor (S4-21). If it has 
completed, the stapling operation is ended (S4-22). Then, the staple 
sequence counter is set to 6. If the answer of the step S4-19 is negative 
(NO), the stapling operation is not performed and, instead, the chuck SOL 
626 is turned off (S4-24). Thereafter, the sequence counter is set to 8 
(S4-25). 
When the staple sequence counter is 6 (S4-26), the chuck motor 646 is again 
moved forward (S4-27, FIG. 72G) to return the stapled paper stack to the 
bin 350. After the chuck motor 646 has been rotated by a predetermined 
number of pulses (S4-28), it is stopped (S4-29) and the chuck SOL 626 is 
turned off (S4-30) to open the chuck arms 622 and 624. Thereupon, the 
timer is started (S4-31) and, on the lapse of the response time of 0.2 
second of the chuck SOL 626 (S4-32), it is stopped (S4-33). Subsequently, 
the staple sequence counter is set to 7 (S4-34). 
When the staple sequence counter is 7, the chuck 620 is shifted to a 
position where it can be lowered to the next bin 350 without contacting 
the bin 350 with the stapled paper stack. Such a procedure reduces the 
interval per bin between the chucking and the end of stapling and thereby 
increases the system productivity. Specifically, the chuck motor 646 is 
started (S4-35), moved backward by the predetermined number of pulses 
(S4-36), and then stopped (S4-37). Subsequently, the staple sequence 
counter is set to 8 (S4-38). 
When the staple sequence counter is 8, meaning that the stapling operation 
has completed, the elevation motor 720 is turned on (S4-39, FIG. 73I) to 
elevate the stapler unit 700. As soon as the elevation home sensor 729 
turns on (S4-40), the elevation motor 720 is deenergized (S4-41) and the 
staple sequence counter is reset to 0 (S4-42). 
The sequence of steps associated with the values 0 to 8 of the staple 
sequence counter is executed until the stapling operation completes. 
Subsequently, the size shift motor 515 is turned on. When the size home 
sensor 501 turns on, the motor 515 is turned on. It is to be noted that 
the return of the stapler unit 700 to the home position and the movement 
of the jogger shaft 502 may be effected at the same time or in the 
opposite order to the illustrative embodiment. Regarding the jogger shaft 
502, it may be moved after all the paper stacks on the bins 350 have been 
removed, i.e., when the bin sensors 321 and 323 have turned off. 
The slow-up and slow-down funtions associated with the up-down movement 
will be described. This functions are such that the moving speed is 
sequentially increased at the beginning of an up-down movement, and 
maintained constant on reaching a predetermined value, and that the moving 
speed is sequentially decreased at the end of an up-down movement before a 
bin of interest is reached, maintained constant on reaching a 
predetermined value, and then decreased to zero at the bin of interest. 
With such functions, it is possible to promote effective use of the torque 
of the elevation motor 720 and to insure accurate stops. 
FIG. 73 is a flowchart demonstrating the slow-up and slow-down procedures. 
As shown, in a subroutine which is called every 1 millisecond, if the 
slow-up operation has not been completed (S5-2) after the turn-on of the 
elevation motor 720 (S5-1), a slow-up counter is incremented by 1 every 
time the subroutine is called (S5-3). Among a group of speed data stored 
in the ROM 801 and set such that the speed sequentially increases, speed 
data is read out on the basis of the value of the slow-up counter (S5-4) 
and set in the CTC 804 (S5-5). In response, the CTC 804 generates 
frequencies based on the speed data and feeds them to the phase signal 
generator 813, FIG. 67. The phase signal generator 813 delivers a phase 
signal to the constant current driver 812 with the result that the 
elevation motor 720 is rotated at speeds associated with the speed data. 
When the slow-up counter reaches a predetermined value (S5-6), the slow-up 
sequence is ended (S5-7) so that the elevation motor 720 is rotated at a 
constant speed. 
On the lapse of a predetermined period of time, a slow-down sequence begins 
(S5-8). A slow-down counter is incremented every time the subroutine is 
called (S5-9). Among a group of speed data loaded in the ROM 801 and set 
such that the speed sequentially decreases, speed data associated with the 
value of the slow-down counter is read out (S5-10) and set in the CTC 804 
(S5-11). Then, the CTC 804 generates frequencies based on the speed data 
and delivers them to the phase signal generator 813. In response, the 
phase signal generator 813 feeds a phase current to the constant current 
driver 812 to drive the elevation motor 720 at speeds associated with the 
speed data. 
When the slow-down counter reaches a predetermined value (S5-12), the 
slow-down sequence is ended (S5-13). Thereafter, the elevation motor 720 
is rotated at a constant speed. As the stapler reaches a bin of interest, 
the slow-up and slow-down counters are cleared (S5-14). The chuck motor 
646 is also subjected to such a slow-down sequence. 
FIGS. 74 and 75 show another specific configuration of the paper pulling 
device 615 which is essentially similar to the configuration described 
with reference to FIG. 53 and successive figures, except for an extension 
616. Specifically, the extension 616 of the paper pulling device is so 
located as to face the opening 701 of the stapler 701 for pressing a paper 
sheet. As shown in FIG. 75, the extension 616 is positioned at a slightly 
lower level than the top of the opening 701a of the stapler 701. The paper 
pulling device 615 with the extension 616, therefore, can surely guide a 
paper sheet from the opening 701a to the stapling position even if the 
paper sheet is noticeably curled and tends to lift itself beyond the top 
of the opening 701a. 
In summary, the present invention achieves various unprecedented advantages 
as enumerated below. 
(1) Chucks of a paper pulling device shift a paper stack by chucking the 
paper stack at two or more points of the latter and thereby frees the 
paper stack from moments otherwise acting on it to bring about skew. The 
paper stack can, therefore, be surely stapled at a predetermined stapling 
position while remaining in the neatly regulated position. This is 
practicable only with a plurality of chucks, i.e., without resorting to a 
bulky device otherwise required to guide a paper stack, cutting down the 
cost. 
(2) A point of force acting on a lower rotatable lever is located between 
the fulcrum of rotation of an upper lever and an upper chuck, while an 
axis of rotation is provided between a portion of the lower lever that 
contacts the point of force and the lower chuck. In this configuration, 
the displacement of the lower chuck is smaller than that of the upper 
chuck so that the lower chuck is prevented from catching paper sheets. 
This insures chucking and, therefore, accurate stapling. All that is 
required is changing the position of the fulcrums of rotation of the 
levers, i.e., it is not necessary to change the gear teeth ratio or the 
leverage. This contributes a great deal to the reduction of cost. 
(3) The paper pulling device is driven by a stepping motor capable of 
accelerating and decelerating with substantially constant acceleration. 
This promotes easy control over the acceleration and deceleration of the 
device. A paper stack is shifted in substantially the same acceleration 
condition and, therefore, stapled without the neatly stacked position 
being disturbed. Of course, the simple control over acceleration and 
deceleration leads to the cut-down of cost. 
(4) A stapler has an opening for accommodating a paper stack while the 
paper pulling device has a member for guiding the leading edge of a paper 
stack to the opening. This eliminates the need for means otherwise 
provided on the individual bins for pressing paper sheets, allowing a 
paper stack to be positioned and stapled at low cost. 
Various modifications will become possible for those skilled in the art 
after receiving the teachings of the present disclosure without departing 
from the scope thereof.