FIELD OF THE INVENTION AND RELATED ART
[0001] The present invention relates to a sheet processing apparatus which is employed in,
for example, a copying machine, a laser beam printer, or the like. More specifically,
it relates to a sheet processing apparatus which comprises a first means (hereinafter,
"processing tray") and a second means (hereinafter, "stacking tray"), for processing,
for example, sorting or binding, the sheets discharged from the main assembly of an
image forming apparatus.
[0002] In the past, a large number of inventions related to an apparatus constituted of
a combination of a processing tray for stapling sheets as needed, and a stacking tray
which receives and stores the sheets, have been submitted for a patent. One of such
inventions is disclosed in U.S. Patent No. 5,021,837. Figure 38 is a schematic vertical
section of the apparatus depicted in the invention.
[0003] In this drawing, referential figure 501 and 502 designate a processing tray and a
stacking tray, respectively. Along the periphery of the processing tray, a stapler
503 for binding sheets, and a jogger 504 which shuttles in the direction perpendicular
to the drawing to align sheets, are disposed.
[0004] With the provision of the above described structure, a set of sheets is discharged
into the stacking tray 502 by a pair of sheet discharge rollers 505 and 506 after
being aligned and stapled in the processing tray (stapling tray). The stacking tray
502 is enabled to alternately move frontward and backward (in the direction of sheet
width) each time a stapled set of sheets is discharged into the stacking tray 502,
so that the stapled sets of sheets are sorted as they are discharged into the stacking
tray 502. It is also enabled to move vertically so that it aligns with the pair of
discharge rollers 505 and 506 each time a stapled set of sheets is discharged. In
other words, the stacking tray 502 gradually descends while alternately moving frontward
and backward to sort the stapled sets of sheets.
[0005] Both the processing tray and the stacking tray 502 are slanted so that their downstream
sides (left side of the drawing) are slightly higher. Therefore, the sheets are regulated,
on the trailing edge side, by the trailing edge side wall 507.
[0006] As an image forming operation continues, the number of sheets which are discharged
into, and stacked in, the stack tray 502 becomes large. As a result, the sheets in
the bottom portion of the stack are subjected to a large amount of pressure generated
by the weight of the sheets stacked above, hence the contact pressure between the
trailing edges of the sheets in the bottom portion of the stack, and the trailing
end wall 507, becomes very large. In the case of the apparatus based on the prior
art, the stacking tray 502 is alternately moved frontward and backward in this condition,
to sort the sheets. Therefore, the trailing edges of the sheets in the bottom portion
of the stack are liable to sustain damages such as scratching, buckling, or the like
anomalies, due to the friction between them and the trailing end wall 507.
[0007] Further, in the case of a sheet processing apparatus based on the prior art, each
sheet is discharged without being aligned with the preceding sheets, and therefore,
a sheet processing apparatus based on the prior art could be improved greatly in terms
of sheet alignment.
[0008] Further, in the case of a sheet processing apparatus based on the prior art, when
a large number of sheets is discharged one by one into a stacking tray to be aligned
as a set of sheets, the sheets which are already in the stack tray are liable to be
disturbed, and therefore, means for holding them down from above, or the like, is
necessary.
SUMMARY OF THE INVENTION
[0009] Accordingly, the object of the present invention is to provide a sheet processing
apparatus comprising a means for desirably stacking sheets, in terms of alignment.
[0010] According to an aspect of the present invention, there is provided a sheet processing
apparatus comprising first stacking means for stacking sheets discharged thereto;
feeding means for feeding a set of sheets from said first stacking means; second stacking
means for stacking the set of sheets fed by said feeding means; shifting means for
shifting the sheets stacked on said first stacking means; control means for grouping
the sheet in a set into a plurality of groups of sheets, and stacking, shifting and
feeding the sheets, for each group, to said first stacking means, and for stacking
the set of sheets on said second stacking means.
[0011] According to another aspect of the present invention, there is provided a sheet processing
apparatus comprising first stacking means for stacking sheets discharged thereto;
feeding means for feeding a set of sheets from said first stacking means; second stacking
means for stacking the set of sheets fed by said feeding means; shifting means for
shifting the sheets stacked on said first stacking means; control means for grouping
the sheet in a set into a plurality of groups of sheets, and stacking, shifting and
feeding the sheets, for each group, to said first stacking means, and for stacking
the set of sheets on said second stacking means, said control means controlling said
shifting means to stack a set of sheets and a set of sheets at offset positions on
said stacking means.
[0012] According to a further aspect of the present invention, there is provided a sheet
processing apparatus comprising first stacking means for stacking sheets discharged
thereto; feeding means for feeding a set of sheets from said first stacking means;
second stacking means for stacking the set of sheets fed by said feeding means; aligning
means for aligning the sheets stacked on said first stacking means; control means
for grouping the sheet in a set into a plurality of groups of sheets, and stacking,
aligning and feeding the sheets, for each group, to said first stacking means, and
for stacking the set of sheets on said second stacking means.
[0013] As described above, according to the present invention, a sheet set to be transferred
from the first stacking means to the second stacking means is shifted, relative to
the immediately preceding set of sheets, prior to its transfer onto the second stacking
means, so that it does not need to be shifted after it is transferred into the second
stacking means. Therefore, such sheet misalignment that occurs when a set of sheets
is shifted in the second stacking means of a processing apparatus based on the prior
art can be prevented, and also, the power source for driving the sheet processing
means can be reduced in size.
[0014] Further, according to the present invention, when a set of a large number of sheets
is transferred from the first stacking means to the second stacking means, the sheet
set is divided into a number of sub-sets comprising a smaller number of sheets, and
then, each sub-set of sheets is separately transferred into the second stacking means,
and therefore, even a plurality of sets of a large number of sheets can be desirably
stacked in terms of sheet alignment within in each set, and in terms of their displacement
in the alternate direction, relative to the adjacent sets.
[0015] Further, according to the present invention, when a set of sheets constituted of
a large number of sheets is processed, the set is divided into two or more sub-sets
constituted of a relatively small number of sheets, and then, each sub-set of sheets
is aligned independently from other sub-sets, and then discharged. Therefore, two
or more sets of sheets can be stacked in a desirably staggered arrangement.
[0016] These and other objects, 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
[0017] Figure 1 is a vertical section of the sheet processing apparatus in an embodiment
of the present invention, and depicts the general structure of the apparatus.
[0018] Figure 2 is a vertical drawing as seen from the front side of the apparatus, of the
stapler, the processing tray, and their adjacencies, in the apparatus illustrated
in Figure 1.
[0019] Figure 3 is a drawing as seen from the direction of an arrow mark
a in Figure 2, of the stapler, the processing tray, and their adjacencies, in the apparatus
illustrated in Figure 1. It depicts the mechanism for moving the stapler.
[0020] Figure 4 is a drawing as seen from the direction of an arrow mark
b in Figure 2, of the stapler and the adjacencies thereof, in the apparatus illustrated
in Figure 1. It depicts the back side of the stapler.
[0021] Figure 5 is a drawing as seen from the front, of the oscillating guide, the processing
tray, and their adjacencies, in the apparatus illustrated in Figure 1.
[0022] Figure 6 is a horizontal drawing of the processing tray, the mechanism for moving
the aligning wall, and their adjacencies, in the apparatus illustrated in Figure 1.
[0023] Figure 7 is a horizontal drawing of a shuttling tray in the apparatus illustrated
in Figure 1.
[0024] Figure 8 is a horizontal drawing of the stacking tray in the apparatus illustrated
in Figure 1.
[0025] Figure 9 is a schematic vertical section of the processing apparatus in the first
embodiment of the present invention, and shows the locations of the sensors disposed
around the stacking tray.
[0026] Figure 10 is a side view of the punching unit in the apparatus illustrated in Figure
1.
[0027] Figure 11 is also a side view of the punching unit in the apparatus illustrated in
Figure 1.
[0028] Figure 12 is a top view of the punching unit in the apparatus illustrated in Figure
1.
[0029] Figure 13 is a top view of the mechanism for moving the sheet edge registration sensor,
of the punching unit in the apparatus illustrated in Figure 1.
[0030] Figure 14 is also a top view of the mechanism for moving the sheet edge registration
sensor, of the punching unit in the apparatus illustrated in Figure 1.
[0031] Figure 15 is a schematic vertical section of the top portion of the sheet processing
apparatus in the first embodiment of the present invention, and depicts the operation
of the sheet processing apparatus in a non-sorting mode.
[0032] Figure 16 is also a schematic vertical section of the top portion of the sheet processing
apparatus in the first embodiment of the present invention, and depicts the operation
of the sheet processing apparatus in a stapling/sorting mode.
[0033] Figure 17 is also a schematic vertical section of the top portion of the sheet processing
apparatus in the first embodiment of the present invention, and depicts the operation
of the sheet processing apparatus in a stapling/sorting mode.
[0034] Figure 18 is also a schematic vertical section of the top portion of the sheet processing
apparatus in the first embodiment of the present invention, and depicts the operation
of the sheet processing apparatus in a stapling/sorting mode.
[0035] Figure 19 is also a schematic vertical section of the top portion of the sheet processing
apparatus in the first embodiment of the present invention, and depicts the operation
of the sheet processing apparatus in a stapling/sorting mode.
[0036] Figure 20 is also a schematic vertical section of the top portion of the sheet processing
apparatus in the first embodiment of the present invention, and depicts the operation
of the sheet processing apparatus in a stapling/sorting mode.
[0037] Figure 21 is a schematic vertical section of the processing tray and the adjacencies
thereof, and depicts the operation of the sheet processing apparatus in a stapling/sorting
mode.
[0038] Figure 22 is also a schematic vertical section of the processing tray and the adjacencies
thereof, and depicts the operation of the sheet processing apparatus in a stapling/sorting
mode.
[0039] Figure 23 is also a schematic vertical section of the processing tray and the adjacencies
thereof, and depicts the operation of the sheet processing apparatus in a stapling/sorting
mode.
[0040] Figure 24 is a schematic vertical section of the top portion of the sheet processing
apparatus in the first embodiment of the present invention, and depicts the operation
of the sheet processing apparatus in a sorting mode.
[0041] Figure 25 is also a schematic vertical section of the top portion of the sheet processing
apparatus in the first embodiment of the present invention, and depicts the operation
of the sheet processing apparatus in a sorting mode.
[0042] Figure 26 is a side view of the stacked sets of sheets in a sorting mode.
[0043] Figure 27 is a top view of the processing tray in the first embodiment of the present
invention, and depicts the sheet aligning operation of the processing tray.
[0044] Figure 28 is also a top view of the processing tray in the first embodiment of the
present invention, and depicts the sheet aligning operation of the processing apparatus.
[0045] Figure 29 is a front view of the processing tray in the first embodiment of the present
invention, and also depicts the sheet aligning operation of the processing apparatus.
[0046] Figure 30 is a top view of the processing tray in the first embodiment of the present
invention, and depicts the sheet aligning operation of the processing apparatus.
[0047] Figure 31 is also a top view of the processing tray in the first embodiment of the
present invention, and depicts the sheet aligning operation of the processing apparatus.
[0048] Figure 32 is also a top view of the processing tray in the first embodiment of the
present invention, and depicts the sheet aligning operation of the processing apparatus.
[0049] Figure 33 is also a top view of the processing tray in the first embodiment of the
present invention, and depicts the sheet aligning operation of the processing apparatus.
[0050] Figure 34 is an operational flow chart of the processing apparatus in the first embodiment
of the present invention, in a hole punching mode.
[0051] Figure 35 is a schematic vertical section as seen from the front, of an image forming
apparatus compatible with a sheet processing apparatus in accordance with the present
invention.
[0052] Figure 36 is a tap view of the processing tray and its adjacencies in the second
embodiment of the present invention.
[0053] Figure 37 is a side view of the processing tray and its adjacencies in the second
embodiment of the present invention.
[0054] Figure 38 is a vertical section of a sheet processing apparatus based on the prior
art, and an image forming apparatus comprising such a sheet processing apparatus.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0055] Figure 35 shows the main assembly of a typical image forming apparatus (main assembly
of a copying machine) comprising a sheet processing apparatus in accordance with the
present invention.
[0056] The main assembly of an image forming apparatus (main assembly of a copying machine)
comprises a platen glass 906 as an original placement table, a light source 907, a
lens system 908, a sheet feeding portion 909, an image forming portion 902, an automatic
original feeding apparatus 500 for automatically delivering a sheet of original onto
the platen glass 906, a sheet processing apparatus 1 which stacks the sheets discharged
from the main assembly of the copying machine after an image is formed on the sheets,
etc.
[0057] The sheet feeding portion 909 is constituted of cassettes 910 and 911, which store
a plurality of recording sheets P, and are removably installable in the apparatus
main assembly 300, and a deck 913 mounted on a pedestal 912. The image forming portion
902 is constituted of a cylindrical photosensitive drum 914, a developing device 915,
a charger 916 for image transfer, a charger 917 for sheet separation, a cleaner 918,
a primary charging device 919, and the like, wherein the photosensitive drum 914 is
surrounded by the rest of the above devices. On the downstream side of the image forming
portion 905, a conveying apparatus 920, a fixing apparatus 904, a discharge roller
pair 905, and the like are disposed.
[0058] Next, the operation of this image forming apparatus will be described.
[0059] As a sheet feeding signal is outputted from a controlling apparatus 930 disposed
on the apparatus main assembly 300 side, a sheet P is fed into the apparatus main
assembly from the cassette 910, the cassette 911, or the deck 913. Meanwhile, an original
D on the original placement table 906 is illuminated by the light source 907, and
the light reflected by the original D is projected onto the photosensitive drum 914
which is charged by the primary charging device 919 prior to its exposure to the reflected
light from original D, through the lens system 908. As the photosensitive drum 914
is exposed to the light reflected by the original D, an electrostatic latent image
is formed on the photosensitive drum 914, and this electrostatic latent image is developed
by the developing device 915 into a toner image.
[0060] The sheet S fed from the sheet feeding portion 909 is straightened by a registration
roller 901 in terms of its angle relative to the direction in which the sheet S is
fed, and then is conveyed to the image forming portion 902 in synchronism with the
toner image also by the registration roller 901. In the image forming portion 902,
the toner image on the photosensitive drum 914 is transferred onto the sheet S by
the charging device 916 for image transfer. After the toner image is transferred onto
the sheet S, the sheet S is charged to the polarity opposite to the polarity to which
the sheet S is charged by the charging device 916 for image transfer. As a result,
the sheet S is separated from the photosensitive drum 914.
[0061] After its separation from the photosensitive drum 914, the sheet S is conveyed to
the fixing apparatus 904 by the conveying apparatus 920. In the fixing apparatus 904,
the toner image on the sheet S is permanently fixed to the sheet S. The sheet S with
the permanently fixed toner image is discharged from the apparatus main assembly 300
by the discharge roller pair 905.
[0062] After a permanent image is formed on the sheet S fed into the apparatus main assembly
300 from the sheet feeding portion 909, the sheet S is discharged into the sheet processing
apparatus 1 in accordance with the present invention.
[0063] Next, the embodiments of the present invention will be described with reference to
the drawings.
[0064] In Figure 1, referential figures 1 and 300 designate a finisher, and the main assembly
of an image forming apparatus. Here, the detailed description of the apparatus main
assembly 300 and the RDF will be not be given. A referential figure 399 designates
a discharger roller pair; 2, the entrance roller pair of the finisher 1; 3, a conveyer
roller pair; 31, a sheet detection sensor; 50, a hole punch unit for punching a hole
in the delivered sheet, along the trailing edge of the sheet; and a referential figure
5 designates a large conveyer roller which conveys the sheet, in cooperation with
holding rollers designated by the referential figures 12, 13, and 14.
[0065] Designated by a referential figure 11 is a flapper which switches the sheet path
between a non-sorting path 21 and a sorting path 22. A referential figure 10 designates
a flapper which switches the sheet path between the sorting path 22, and a buffer
path 23 for temporarily holding the sheet. A referential figure 6 designates a conveyer
roller pair; 130, an intermediary tray (hereinafter, "processing tray") which temporarily
accumulates sheets, aligns them, and staples them; 7, a discharge roller pair for
discharging the sheet onto a processing tray (first stacking tray) 130; 150, an oscillating
guide; 180a and 180b, sheet set discharge rollers, which are supported on the processing
tray 130 and the oscillating guide 150, respectively, and coordinate with each other,
as means for discharging a sheet set, to convey the sheets on the processing tray
130 when the oscillating guide 150 is at the closed position; a reference figure 200
designates a stacking tray (second stacking tray).
[0066] Next, the stapling unit 100 will be described with reference to Figure 2 (vertical
drawing), Figure 3 (horizontal drawing as seen from the direction of an arrow mark
a), and Figure 4 (vertical drawing as seen from the direction of the arrow
b in Figure 2).
[0067] A stapler (binding means) 101 is fixed to a movable base 103, with the interposition
of a holder 102. On axes 104 and 105 fixed to the movable base 103, rollers 106 and
107 are rotatively mounted, and the rollers 106 and 107 are fitted in an elongated
track, or hole, (tracks 108a, 108b, and 108c) cut in a guide plate 108.
[0068] The rollers 106 and 107 have flanges 106a and 107a, respectively, the diameters of
which are larger than the width of the track of the guide plate 108. The movable base
103 also comprises three guide rollers 112, which are attached to the underside of
the movable base 103, and rollers 109, which also are attached to the underside of
the movable base 103. Thus, the movable base 103 which holds the stapler 101 can smoothly
move following the tracks (108a, 108b, and 108c) of the guide plate 108, without ever
coming off the track.
[0069] The aforementioned track hole (108a, 108b, and 108c) has a spur track parallel to
the main track, at both the front and rear ends. With this arrangement, as the stapler
101 is moved to the front, it becomes diagonally positioned relative to the sheet
edge since the roller 106 moves into the spur track 108b and the roller 107 remains
in the main track 108a, whereas when it is at the center, it is parallel to the sheet
edge since both rollers 106 and 107 remain in the main track 108a.
[0070] As the stapler 101 is moved to the rear, it becomes diagonally positioned, relative
to the sheet edge, in the direction opposite to the diagonal direction in which the
stapler is positioned at the front of the apparatus, since the roller 106 remains
in the main track 108a, and the roller 107 moves into the spur track 108c.
[0071] After the two rollers 106 and 107 move into the correspondent spur tracks, the stapler
is moved holding the diagonal orientation. The operation for changing the orientation
of the stapler 101 is triggered by an unillustrated cam.
[0072] Next, the mechanism for moving the stapler 101 will be described.
[0073] The roller 106, one of the rollers of the movable base 103, integrally comprises
a pinion gear 106b and a belt pulley 106c. The pinion gear 106b is linked to a motor
M100, with a belt stretched between the pulley 106c and the pulley of the motor M100.
To the bottom surface of the track plate 108, a rack gear 110, which engages with
the pinion gear 106b, is fixed along the track. With this arrangement, as the motor
M100 is rotated forward or backward, the movable base 103 is moved frontward or rearward,
holding the stapler 101.
[0074] To the bottom surface of the movable base 103, axes 111 are attached, which extend
downward. Around each axis 111, the aforementioned roller 112 is fitted, which plays
a role in rotating the trailing end stopper 131 of the processing tray 130, which
will be described later, so that the stopper 131 is prevented from colliding with
the stapler 101. The details of this arrangement will be described next.
[0075] The stapler unit 100 comprises a sensor for detecting the home position of the stapler
101. Normally, the stapler 101 is on standby at the home position (in this embodiment,
the most front position).
[0076] Now, the trailing end stopper 131 which holds the trailing edges of the sheets P
stacked in the processing tray 130 will be described.
[0077] The trailing end stopper 131 comprises: a sheet holding surface 131a, which is perpendicular
to the stacking surface of the processing tray 130 when the stopper 131 is erected;
a pin 131b which is inserted in the round hole of the processing tray 130 to rotatively
attach the stopper 131 to the processing tray 130; and a pin 131c which connects the
stopper 131 to a linkage which will be described later. The linkage comprises a main
link 132 and a sub-link 133. The main link 132 has a cam surface 132a which is pushed
by the roller 112 attached to the movable base 130 for the stapler 101. The sub-link
133 connects the top end pin 132b of the main link 132 and the pin 131c of the trailing
end stopper 131c.
[0078] The main link 132 swings around a shaft 134 fixed to an unillustrated frame. To the
bottom end of the main link 132, a tension spring 135 is attached to generate tension
to rotate the main link 132 in the clockwise direction, and therefore, the main link
is normally kept in contact with a bumper plate 136, keeping thereby the trailing
end stopper 131 perpendicular to the processing tray 130.
[0079] As the movable staple base 103 is moved, the pusher roller 112 attached to the movable
staple base 103 is caused to push the cam surface 132a of the main link 132 connected
to the trailing end stopper 131 which is blocking the path of the stapler 101. As
a result, the trailing end stopper 131 is pulled, being thereby rotated downward,
by the sub-link 133 to a location at which it does not interfere with the stapler
101. In order to make sure that the trailing end stopper 131 is kept at the collision
avoidance position while the stapler is moving, two or more pusher rollers 112 are
provided (three, in this embodiment).
[0080] To each of the front and rear plates of a stapler holder 102 for supporting the stapler
101, a stopper 113 (outlined with a double dot chain line) is attached, the surface
of which on the processing tray side is contoured like the surface of the trailing
end stopper 131. Therefore, even when the stapler 101 is at the center position (center
of the track 108a), hence the trailing end stopper 131 is at the collision avoidance
position, the trailing edges of the sheets are properly held by the stopper 113 of
the stapler holder 102.
[0081] Next, referring to Figure 5, a description will be given as to a processing tray
unit 129.
[0082] The processing unit 129 is disposed between a conveyer portion for conveying the
sheets from the main assembly 300 of an image forming apparatus toward the stacking
tray 200, and the stacking tray 200 which receives and stores the processed sets of
sheets.
[0083] The processing tray unit 129 is constituted of the processing tray 130, the trailing
end stopper 131, an aligning means 140, the oscillating guide 150, a sheet paddling
member 160, a shuttling tray 170, and a sheet set discharge roller pair 180.
[0084] The processing tray 130 is slanted, with the downstream side (left side of the drawing)
being the higher side, and the upstream side (right side of the drawing) being the
lower side. To the lower side, the trailing end stopper 131 is attached. After being
discharged by the discharge roller pair 7 of the conveyer portion, the sheet P slides
on the processing tray 130, due to its own weight, and also by the function of the
sheet paddling member 160, which will be described later, until its trailing edge
comes in contact with the trailing end stopper 131.
[0085] To the higher end portion of the processing tray 130, the sheet set discharge roller
180a is attached, and to the oscillating guide 150, which will be described later,
the sheet set discharge roller 180b, which makes contact with the sheet set discharge
roller 180a, is attached. Both rollers 180a and 180b are rotatively drivable in the
forward or backward direction by a motor M180.
[0086] Next, the aligning wall (sheet aligning means) 140 will be described with reference
to Figure 6 which is the drawing of the aligning wall 140 as seen from the direction
of an arrow mark
c in Figure 5.
[0087] Aligning members 141 and 142 constitute the aligning means. The aligning member 140
is the front one, and the aligning means 142 is the rear one, and they are independently
movable in the forward or rearward direction. Both the front aligning member (first
aligning member) and the rear aligning member (second aligning member) comprise: portions
with aligning surfaces 141a and 142a, respectively, which stand upright relative to
the sheet supporting surface of the processing tray130, and press the lateral edges
of the sheets; portions with sheet supporting surfaces 141c and 142c, which are perpendicular
to the aligning surfaces 141a and 141b, respectively, and support the sheet P from
below; and gear portions with rack gears 141b and 142b, respectively, which extend
in the front to rear direction in parallel to the sheet supporting surface of the
processing tray 130. The two aligning members are fitted in correspondent guides which
extend in the direction perpendicular to the sheet conveyance direction, with the
aligning surfaces 141a and 142a standing upright above the sheet supporting surface
of the processing tray 130, and the gear portion sticking downward below the bottom
surface of the processing tray 130.
[0088] The rack gears 141b and 142b are meshed with correspondent pinion gears 143 and 144,
respectively, which are linked to motors M141 and M142, respectively, through the
pulleys and belts. Thus, as the motors are rotated forward or backward, the aligning
members 141 and 142 are moved frontward or backward. Both aligning members 141 and
142 are provided with home position sensors S1 and S2, respectively, and normally,
both are on standby at their home positions.
[0089] In this embodiment, the home position of the front aligning member 141 is the most
front position, and the home position of the rear aligning member 142 is the rearmost
position.
[0090] The downstream side (left side of the drawing) of the oscillating guide 150 supports
the aforementioned sheet set discharge roller 180b, and the upstream side (right side
of the drawing) of the oscillating guide 150 is supported by an axis 151. Normally,
when sheets P are discharged one by one into the processing tray 130, the oscillating
guide 150 remains at an open position, at which the sheet set discharge rollers 180a
and 180b remain separated from each other, being thereby prevented from interfering
with the sheets P while the sheets P are discharged, fall into the processing tray
130, and are aligned, whereas when the sheets P are discharged all together as a set
of sheets from the processing tray 130 into the stacking tray 200, the oscillating
guide 150 remains at a closed position, at which the sheet discharge rollers 180a
and 180b remain in contact with each other.
[0091] A rotative cam 152 is disposed immediately below the lateral edge of the oscillating
guide 150. As the rotative cam 152 is rotated, it makes contact with the lateral edge
of the oscillating guide 150, and pushes up the oscillating guide 150, causing the
oscillating guide 150 to pivot about the axis 151, in other words, open up. Then,
as the rotative cam 152 is rotated 180° from the point at which the oscillating guide
150 begins to open, the rotative cam 152 separates from the lateral edge of the oscillating
guide 150, allowing thereby the oscillating guide 510 to close. The rotational movement
of the rotative cam 152 is caused by a motor M150 linked to the rotative cam 152 through
a driving system.
[0092] The home position of the oscillating guide 150 is the position at which it is open,
and in order to determine whether the oscillating guide 150 is at the home position
or not, the apparatus is provided with a sensor S3.
[0093] Next the sheet paddling member 160 will be described.
[0094] The sheet paddling member 160 is solidly attached to an axis 161, and the axis 161
is rotatively supported by the front and rear panels, and is linked to a motor M160,
which rotates the sheet paddling member 160 in the counterclockwise direction. The
length of the sheet paddling member 160 is rendered slightly longer than the distance
between the axis 161 and the sheet supporting surface of the processing tray 130.
The home position for the sheet paddling member 160 is set at a position (outlined
by a solid line in Figure 5) at which the sheet paddling member 160 does not come
in contact with the sheet P when the sheet P is discharged into the processing tray
130 by the discharge roller pair. The sheet P is discharged, with the sheet paddling
member 160 being at the home position. As the sheet P lands in the processing tray
130, the sheet paddling member 160 is rotatively driven by the motor M160 in the counterclockwise
direction, paddling the sheet P toward the trailing end stopper 131, and thereby,
making sure that the trailing edge of the sheet P squarely comes in contact with the
trailing end stopper 131. Then, the sheet paddling member 160 is rotated back to the
home position after a predetermined interval, and then, remains at the home position,
on standby for the next sheet discharge.
[0095] Next, the shuttling tray 170 will be described with reference to Figure 7 which is
the drawing of the shuttling tray 170 as seen from the direction of an arrow mark
d in Figure 5.
[0096] The shuttling tray 170 is located below the sheet set discharge roller 180a, and
moves in or out in the sheet conveyance direction (direction indicated by an arrow
mark
x in Figure 5), substantially in parallel to the lateral edge of the inclined processing
tray 130. When the shuttling tray 170 is out (outlined by a double dot chain line
in Figure 5), its edge on the downstream side relative to the sheet discharge direction
is above the approximate center of the stacking tray 200, and when it is in, or retracted,
(outlined by a solid line in Figure 5), the same edge is on the right-hand side of
the sheet set discharge roller pair. It should be noted here that the processing tray
unit 129 is so structured that when the shuttling tray 170 is out, it reaches far
enough to prevent the gravitational center of the sheet P from going beyond the downstream
edge of the tray 170, relative to the sheet discharge direction, as the sheet P is
discharged into the processing tray 130.
[0097] The shuttling tray 170 is supported by a rail 172 fixed to a frame 171, and is rendered
movable in the sheet discharge direction. More specifically, a rotational link 173,
which rotates about an axis 174, is fitted in the grooves provided on the bottom surface
of the shuttling tray 170. Therefore, as the rotational link 173 rotates once, the
shuttling tray 170 shuttles once as described above.
[0098] The rotational link 173 is driven by a motor M170 through an unillustrated driving
mechanism. The home position for the shuttling tray 170 is the "in" position (outline
by a solid line in Figure 5), and whether or not the shuttling tray 170 is at the
home position is detected by an unillustrated sensor.
[0099] Next, the stacking tray 200 and a sampling tray 201 will be described with reference
to Figures 8 and 9.
[0100] The two trays are optionally employed depending on the situation. The stacking tray
200, which is located below the sampling tray 201, is selected while a copying machine,
a printer, and the like machine is in an ordinary operation, whereas the sampling
tray 201, which is above the stacking tray 200, is selected when the image forming
apparatus is in an optional operation, for example, when the apparatus is in a sampling
mode, an interrupting mode, an overflowing mode, that is, when the stacking tray is
full, a sorting mode, a mixed output mode, or the like.
[0101] Both trays are each provided with a stepping motor 202 so that they can be vertically
moved independently from each other. Each tray is attached to the sheet processing
apparatus by means of fitting a roller 214 (total of four, two on each side of the
tray) attached to the downstream edges of the tray, in a vertical roller track fixed
to the frame of the sheet processing apparatus 1. The vertical edge of the vertical
roller track constitutes a rack 210. The play between the tray and the frame 250 of
the sheet processing apparatus 1 in the front to rear direction of the apparatus is
regulated by a regulating member 215. The stepping motor 202 is attached to the base
plate 211 of the tray, and a pulley is press-fitted around the shaft of the stepping
motor 202. This pulley is linked to a pulley 203 with a timing belt 212 to transmit
driving force from the motor 202 to the pulley 203.
[0102] The pulley 203 is fixed to an axis 213 with the use of a parallel pin, and the axis
213 is fixed to a ratchet 205 also with the use of a parallel pin. The ratchet 205
remains in contact with an idler gear 204 due to the pressure from a spring 206, and
the idler gear 204 is meshed with a gear 207. The gear 207 is meshed with a gear 209
which is meshed with the rack 210. Further, the gear 207 is fixed to an axis 208 to
which the gear 207 on the opposite side of the tray is fixed, so that the driving
force of the motor 202 is transmitted to both sides of the tray. Further, each tray
is fixed to its own base plate 211, constituting a tray unit.
[0103] In order to prevent the tray driving system from being damaged by foreign objects
pinched by the tray driving system when the tray is descending, the tray driving system
is designed so that the aforementioned ratchet is allowed to slip on the surface of
the idler gear 204 against the pressure from the spring 206, only in the direction
in which the ratchet 205 rotates when raising the tray. If the slipping of the ratchet
205 begins, the motor 202 must be immediately stopped. In order to detect the slipping
of the ratchet 205, the apparatus is provided with a sensor S201, which detects the
slit provided in the idler gear 204. This sensor S201 doubles as an synchronism sensor.
Also, in order to allow the tray to vertically move across the processing tray portion
which has the opening which the processing tray 130 faces, the oscillating guide 150
is designed so that when it is at the closed position, its portion becomes a part
of the accumulating wall of the tray; in other words, the tray is allowed to move
only when a sensor (unillustrated) detects that the oscillating guide 150 is at the
closed position.
[0104] A sensor S202 is an area detection sensor, which detects flags present in the area
between an upper limit sensor 203a for preventing the excessive ascending of the tray,
and a sensor S205 for detecting the top of the stack of sheets in the processing tray
130. A sensor S203b for detecting the thousandth sheet on the sample tray is disposed
at a location, the distance from which to a sensor S204 for detecting the surface
of the sheet which comes through the non-sorting path is equivalent to the thickness
of a stack of 1,000 sheets, to use the height of the sheet stack to limit the number
of sheets which are allowed to be stacked in the sampling tray 201.
[0105] A sensor 203c is for using the height of the stack of the sheet sets in the sampling
tray 201 to limit the number of the sheet sets allowed to be discharged into the sampling
tray 201 from the processing tray 130. It is disposed at a location, the distance
from which to a sensor S205 for detecting the surface of the sheet which comes through
the sorting path is also equivalent to the thickness of a stack of 1,000 sheets. A
sensor S203d is for using the height of the stack of the sheet sets in the stack tray
200 to limit the number of the sheet sets allowed to be discharged into the stacking
tray 200 from the processing tray 130. It is disposed at a location, the distance
from which to the sensor S205 for detecting the surface of the sheet which comes through
the sorting path is equivalent to the thickness of a stack of 2,000 sheets. A sensor
S203e is a lower limit sensor for preventing the excessive descending of the stacking
tray 200. Among the above described sensors, only the sheet surface detection sensors
S204 and S205 are of a front-to-rear transmission type. Further, each tray is provided
with a sensor 206 which detects whether or not a sheet is in the tray.
[0106] As for a method for detecting the position of the top sheet, first, the tray is raised
from below each sensor until the sensor is blocked. This is the initial point. Then,
after sheets are stacked, the tray is lowered until the optical axis of the top sheet
sensor becomes unblocked. Thereafter, the tray is raised again until the optical axis
of the top-sheet sensor is blocked. This procedure is repeated.
[0107] Next, the hole punching unit 50 will be described.
[0108] The hole punching unit 50 is constituted of a hole punching means 60 and a lateral
edge detecting means 80. The hole punching means 60 has a hole punch 61 and a die
62, which are axially supported by a casing 63, with the gear of the punch 61 meshing
with the gear of the die 62 so that as they are driven by a punch driver motor 66,
they are synchronously driven in the directions of arrow marks B and C, respectively.
When not in operation, they are at their home positions (H.P.) as illustrated in Figure
10. When in operation, after the sheet detection sensor 31 detects the trailing edge
of the sheet, the punch driver motor 66 is driven with predetermined timing. Then,
the punch 61 and the die 62 are rotated in the directions of the arrow marks B and
C, respectively, and the punch 61 meets with a die hole 62a of the die 62, punching
a hole through a sheet which is being conveyed.
[0109] In order that a hole can be punched through a sheet while the sheet is being conveyed,
the rotational speeds of the punch 61 and the die 62 are rendered the same as the
rotational speed of the aforementioned conveyer roller pair 3. A referential figure
67 designates a guide portion for moving the hole punching means 60 in the direction
perpendicular to the sheet conveyance direction A, and a referential figure 68 designates
a roller which rotates in contact with the guide portion 67. The roller 68 is mounted
on a roller shaft 69 which is attached to the casing 63 by crimping.
[0110] A reference 63a designates a rack gear cut along the edge of the casing 63. It is
meshed with a pinion gear 70 attached to an unillustrated motor for moving the hole
punching means. A reference 71 designates a sensor for detecting whether or not the
hole punching means is at the initial position. It has a light receptor portion 71a
aligned in parallel to the sheet conveyance direction A, and is attached to the casing
63.
[0111] With the above arrangement, the hole punching means 60 is drivable in the direction
indicated by arrow marks D or E, that is, the direction perpendicular to the sheet
conveyance direction A, by the hole punching means moving motor. As the hole punching
means initial position detecting sensor 71 is moved in the arrow E direction, a marker
52 for the initial point for the hole punching means is detected by the light receptor
portion 71a. The initial position for the hole punching means is set at a point away
from the referential sheet edge position by several millimeters which correspond to
the amount of the possible positional deviation of the sheet, for example, slanting
or lateral deviation.
[0112] The lateral edge detecting means 80 is attached to the hole punching means 60. The
lateral edge detecting means 80 is constituted of a sensor 81 for detecting the lateral
edge of a sheet, and a sensor arm 82, to the end of which the sensor 81 is attached.
The sensor 81 has a light receptor portion 81a aligned in parallel to the sheet conveyance
direction A.
[0113] A portion of the sensor arm 83 constitutes a rack gear 82a, which is meshed with
a pinion gear 83 fixed to an unillustrated motor for moving the lateral edge detecting
means 80. This unillustrated motor is attached to the casing 63. To the rear end of
the sensor arm 82, a sensor 84 for detecting the initial position of the lateral edge
of the sheet is attached. The sensor 84 has a light receptor portion 84a aligned in
parallel to the light receptor 81a.
[0114] With the above arrangement, the lateral edge detection sensor 81 and the lateral
edge initial position detection sensor 84 are movable in the direction indicated by
the arrow mark D or E, that is, the direction perpendicular to the sheet conveyance
direction A by the lateral edge detection means moving motor. As the lateral edge
initial position detection sensor 84 is moved in the arrow E direction, a marker 63b
for the lateral edge initial position, which is a part of the casing 63, is detected
by the light receptor portion 84a. Further, lateral edge detection sensor 81 can be
set at a point correspondent to the selected sheet size, by moving the sensor 81 in
the direction of the arrow mark D.
[0115] In order to detect the lateral edge of a sheet, after the aforementioned sheet detection
sensor 31 detects the leading edge of the sheet, the hole punching means moving motor
is activated with predetermined timing to move the hole punching means and the lateral
edge detection sensor 81 in the direction of an arrow mark D. Then, as the light receptor
portion 81a of the lateral edge detection sensor 81 is blocked by the lateral edge
of the sheet, the controlling apparatus determines that the hole punching apparatus
is at the predetermined location relative to the sheet edge, aligning the position
for hole punching means 60 relative to the sheet edge, and thereby, properly aligning
hole positions relative to the sheet edge.
[0116] Next, the flow of a sheet P will be described.
[0117] Referring to Figure 5, as a user selects the non-sorting mode through the control
panel (unillustrated) of the main assembly of an image forming apparatus, the sheet
entrance roller pair 2, conveyer roller 3, and large conveyer roller 5 rotate, conveying
the sheet P discharged from the main assembly 300 of an image forming apparatus. Next,
a flapper 11 is pivoted by a solenoid (unillustrated) to the position illustrated
in the drawing, directing the sheet P into the non-sorting path 21. As the trailing
edge of the sheet P is detected by the sensor 33, the roller 9 is rotated at a speed
appropriate for stacking the sheet P, to discharge the sheet P into the sampling tray
200.
[0118] Next, the operation to be carried out when a user selects the stapling/sorting mode
will be described.
[0119] Referring to Figure 16, the sheet entrance roller pair 2, conveyer roller 3, and
large conveyer roller 5 rotate to convey the sheet P delivered from the apparatus
main assembly 300. The flappers 10 and 11 are positioned as illustrated in the drawing.
The sheet P is moved through the sorting path 22, and is delivered to the stapler
101 by the discharge roller pair 7. At this moment, the shuttling tray 170 is out
to prevent the leading end portion of the sheet P from hanging from the edge of the
sheet processing tray 130, so that the sheet P is not prevented from sliding backward
relative to the sheet conveyance direction, and also to aid the sheet P to be aligned.
[0120] After being discharged, the sheet P begins to slide toward the trailing end stopper
131 due to its own weight, and at the same time, the sheet paddling member 160, which
has been on standby at the home position, starts rotating in the counterclockwise
direction by being driven by the motor M160, aiding the movement of the sheet P. As
soon as the sheet P stops, with the trailing edge of the sheet P being squarely in
contact with the trailing end stopped 131, the rotation of the paddle 160 is stopped.
Then, the aligning member aligns the sheet P. The operation for aligning the sheet
P will be described later.
[0121] After all the sheets P which belong to a given set are discharged into the processing
tray 130, and are aligned, the oscillating guide 150 swings down, as illustrated in
Figure 17, causing the roller 180b to descend on the stack of sheets in the processing
tray 130. Then, the stapler 101 staples the set of sheets.
[0122] Meanwhile, the sheet P1 discharged from the apparatus main assembly 300 is wrapped
around the large conveyer roller since the flapper 10 is positioned as illustrated
in Figure 17, and then, the large conveyer roller 5 is stopped after advancing the
sheet P a predetermined distance from a sensor 32. Then, after the next sheet P2 is
advanced a predetermined distance from a sheet detection sensor 31, the large conveyer
roller 5 is restarted. As a result, the first and second sheets P1 and P2 overlap,
with the second sheet P2 being ahead of the first sheet P by a predetermined distance
as shown in Figure 18. Next, both sheets P1 and P2 are wrapped, being overlapped,
around the large conveyer roller 5 as shown in Figure 19, and then, the large conveyer
roller 5 is stopped after advancing the two sheets P1 and P2 the predetermined distance.
Meanwhile, the set of sheets on the processing tray 130 is discharged into the stacking
tray 200 as shown in Figure 19.
[0123] As for the shuttling tray 170, before the sheet set completely comes out from between
the rollers of the sheet set discharge roller pair 7, the shuttling tray 170 is moved
to the home position to allow the set of sheets to freely fall into the stacking tray
200. Next, as the third sheet P3 reaches a predetermined position as illustrated in
Figure 19, the large conveyer roller 5 is restarted, causing the third sheet P to
overlap with the preceding two sheets P1 and P2, with the sheet P3 being ahead of
the sheet P2 by the predetermined distance as illustrated in Figure 20. Then, the
flapper 10 is pivoted to guide the three sheets P1, P2, and P3 into the sorting path
22.
[0124] At this time, the oscillating guide 150 remains at the bottom position, or the closed
position, so that the leading ends of the three sheets P are pinched between the rollers
180a and 180b as shown in Figure 21. Then, as soon as the trailing edges of the three
sheets P pass the roller pair 7, the rollers 180a and 180b are rotated in reverse
to aid the three sheets P to move backward. But, before the trailing edge of the first
sheet P1 comes in contact with the trailing end stopper 131, the oscillating guide
150 is raised, hence the roller 180b is raised, being thereby separated from the sheet
P. The fourth sheet and the sheets thereafter are also conveyed through the sorting
path 22 in the same manner as the first to third sheets which belong to the first
set are conveyed, and then are discharged into the processing tray. The third set
of sheets, and the sets of sheets thereafter are also conveyed and stacked in the
stacking tray 200 in the same manner as the first and second sets of sheets until
a selected number of sets of sheets are stacked in the stacking tray 200.
[0125] When a plurality of sheets P are conveyed in layers as described above, each sheet
is set slightly ahead of the sheet immediately below, relative to the sheet conveyance
direction; the sheet P2 is set slightly downstream of the sheet P1, and the sheet
P3 is set slightly downstream of the sheet P2, relative to the sheet conveyance direction.
[0126] The amount of deviation between two adjacent sheets and the timing with which the
oscillating guide 150 begins to be raised are related to the time necessary for each
set of sheets to be properly placed in the processing tray 130. In other words, it
is related to the speed at which a set of sheets is moved backward toward the trailing
end stopper 131 by the rollers 180a and 180b, and the processing capacity of the apparatus
main assembly 300. In this embodiment, in which the sheet conveyance speed is 750
mm/sec; the amount of deviation (b) between two adjacent sheets is approximately 20
mm; and the speed at which a set of sheets is moved backward by the rollers 180a and
180b is 500 mm/sec, the timing for raising the roller 180b is set so that the roller
180b is raised when the sheet P1 arrives at a point which is 40 mm (value of a) away
from the trailing end stopper 131.
[0127] Next, the sorting mode will be described.
[0128] A user is to select the sorting mode on an unillustrated control panel after placing
an original on the RDF500, and to press the start button (unillustrated). Then, the
entrance roller pair 2, and conveyer roller 3 are rotated in the directions illustrated
in Figure 24, that is, in the same manner as they are in the stapling/sorting mode,
and stack sheets in the processing tray 130. Then, the sheets are aligned by the aligning
means 140. After a relatively small number of sheets is stacked in alignment on the
processing tray 130, the oscillating guide 150 swings down as shown in Figure 25,
and the rollers 180b and 180a convey the small number of the aligned and stacked sheets
all together.
[0129] The next sheets P are guided into the sheet path above the flapper 10, and are wrapped
around the large conveyer roller 5 as sheets are in the stapling mode. Then, these
sheets P are discharged into the processing tray 130 after the preceding group of
sheets in the processing tray 130 is discharged from the processing tray 130. According
to the tests conducted by the inventors, the number of sheets to be discharged together
as a group of sheets is desired to be no more than 20. Further, the number of sheets
to be discharged as a group of sheets is desired to satisfy the following requirement:
[0130] Number of sheets in a set of originals ≥ Number of sheets to be discharged together
as a group of sheets ≤ 20. The number of sheets in a set of originals means the number
of sheets of a set of originals placed in an apparatus, for example, an image forming
apparatus, which discharges into a sheet processing apparatus, sheets on which an
image has been formed. In other words, it is the same as the number of sheets in one
set of sheets.
[0131] Therefore, when producing a program, if the number of sheets to be discharged together
as a group of sheets is set at five, but the number of sheets in a set of originals
is four, the sheets are discharged in a group of four. If the number of sheets in
a set of originals is five or more, for example, 14, the sheets are aligned and discharged
in two groups of five sheets, and one group of four sheets.
[0132] In other words, when the number of sheets in a set of sheets to be discharged into
the processing tray 130 is no less than a predetermined number (20 or more), the sheets
to be discharged are handled in a sub-set. More specifically, they are discharged
into the processing tray 130 until the number of the sheets discharged into the processing
tray 130 reaches a predetermined number, which is the number of sheets in a sub-set,
and is no less than two, for example, five, and then, as soon as this predetermined
number is reached, the sheets in the processing tray 130 are discharged into the stacking
tray 200 by the sheet set discharge rollers 180a and 180b.
[0133] After all the sheets which belong to the first set are discharged, an aligning wall
141 on the front side is moved with an aligning wall 142 on the rear side so that
the location of the aligned edges of the sheets in the second set becomes slightly
off from that of the first set. More specifically, when two or more sets of sheets
are discharged into the stacking tray 200, after a predetermined number of sheets
which constitute a set are accumulated in the processing tray 130, they are shifted
to a location which is slightly off from the location where the immediately preceding
set is before being discharged after being aligned. Then, they are discharged into
the stacking tray 200 from the processing tray 130, from the location which is slightly
off from where the immediately preceding set is. As a result, as the two or more sets
of sheets are stacked into the stacking tray 200, they are staggered, that is, located
alternately between the first and second positions, which will be described later
in detail.
[0134] Thus, the sheets which belong to the second set are also discharged into the processing
tray 130 in two or more sub-sets, shifted to a location slightly off from the location
at which the sheets belonging to the first set are aligned, are aligned there, and
then, are discharged into the stacking tray 200. After all the sheets in the second
set are processed, the front and rear aligning walls 141 and 142, respectively, are
returned to their original locations at which they align the sheets belonging to the
first set, being readied for aligning the sheets which belong to the third set. The
above sequence is repeated until all sets of sheets are stacked in a staggered arrangement
in the stacking tray 200 as illustrated in Figure 26.
[0135] As described, according to the present invention, when two or more sets of sheets
are to be stacked in the stacking tray 200, and the number of sheets in each set exceeds
a predetermined number, the sheets in each set are discharged into the processing
tray 130 in a sub-set, or a group having a smaller number of sheets than each set,
are aligned, and then, are discharged into the stacking tray 200. Then, after all
the sheets belonging to each set are discharged into the processing tray 130, the
location at which sheets are accumulated and aligned the processing tray 130 is shifted
from the location at which the sheets belonging to the immediately preceding set are
accumulated and aligned. Therefore, a sheet processing apparatus is much improved
in terms of the way two or more sets of sheets are stacked in the stacking tray 200,
and also in terms of sheet alignment in each set of sheets.
[0136] Next, the sheet aligning operation will be described.
[0137] First, when there is not a single sheet in the processing tray 130, in other words,
when the first of the sheets P (for example, three sheets) in a set of sheets is discharged
into the processing tray 130, the front and rear aligning members 141 and 142, which
are on standby at their home positions, are shifted to positions PS11 and PS21, respectively,
which are slightly off from where the lateral edges of the first sheet P will be after
being aligned (Figure 27).
[0138] Then, as described before, as the trailing edge of the third sheet comes in contact
with the trailing end stopper 131, with its bottom surface being in contact with the
sheet supporting surfaces 141c and 142c of the aligning members, the aligning members
141 and 142 are moved to the aligning positions PS12 and PS22, respectively, aligning
the sheets into a predetermined boundary, or the first sheet alignment boundary 190
(Figure 28). Next, the aligning member 141 is moved to the position PS11, and kept
there on standby for the next sheet. Then, as soon as the discharging of the next
sheet is completed, the aligning member 141 is moved to the aligning position PS12,
aligning the sheet into the first sheet alignment boundary 190.
[0139] During the above movement of the front aligning member 141, the rear aligning member
142 remains at the aligning position PS22, playing the role of a referential member,
whereas the front aligning member 141 continues to shuttle between the standby position
P11 and the aligning position P12 until the aligning of the last sheet in the currently
processed set is completed. With the aligning operation described above, it does not
occur that a sheet collides with the inward edges of the sheet supporting portions
of the aligning members, and buckles at the colliding edge like a sheet P is buckling
at the edge after colliding with the edge of the sheet supporting portions 142c of
the aligning member 142, as illustrated in Figure 29.
[0140] After the completion of the aligning, the first set of sheets is stapled if required,
and then is discharged into the stacking tray 200, as described before.
[0141] Next, the sheets, for example, three sheets, which constitute the second set, are
discharged into the processing tray 130. During the discharging of these sheets into
the processing tray 130, the aligning members 141 and 142 remain on standby at the
positions PS11 and PS12 as they do for the sheets of the first set (Figure 27), but
the sheet alignment boundary, or the boundary into which the sheets converge as they
are aligned, is moved to the second sheet alignment boundary 191, which is rearward
of the first sheet alignment boundary by a predetermined margin (Figure 30). For the
third set, the sheet alignment boundary is returned to the first position 190; for
the fourth set, to the second position; and so on. In other words, according to the
present invention, the sheet alignment boundary is alternated for each set between
the first and second positions 190 and 192. As a result, when two or more sets of
sheets are to be processed, they can be stacked in a staggered arrangement in the
stacking tray 200, by a deviation of L.
[0142] The amount L of the deviation may be varied between L1 and L2, depending on whether
the apparatus is in the sorting mode or the stapling mode. For example, in this embodiment,
when in the stapling mode, the amount L is set at approximately 15 mm (L1) since all
that is necessary is to prevent the staples of the adjacent two sets of sheets from
overlapping, whereas when in the sorting mode in which it should be easy to visually
discriminate each set from others, the amount L of the deviation is set at approximately
20 - 30 mm (L2). In other words, the distance the aligning members 141 and 142 are
moved in the stapling mode is reduced to improve the processing speed.
[0143] In the stapling mode, the stapler 101 is on standby at a position correspondent to
the points of a sheet where a staple goes in, and staples the sheets in the processing
tray 130 after the aligning of the last sheet in each set is completed. Further, as
the sheet alignment boundary is moved between the two positions which are apart by
an amount equivalent to the predetermined amount L of the deviation between the adjacent
two sheets, the stapler 101 is also moved accordingly.
[0144] As for the structure for moving the stapler 101 along the edges of sheets, or changing
the angle of the stapler 101, in response to the selected stapling mode (angled single
front stapling, angled single rear stapling, dual central stapling, or the like),
it is the same as described before. However, this structure has a limit in terms of
the range in which the stapler 101 is allowed to maintaining the same stapling posture
(parallel or slanted relative to the sheet edge). In addition, there are so many variations
in sheet size. Therefore, if there is only one pair of sheet alignment boundaries
for all of the stapling modes, there occur situations in which stapling is impossible.
Thus, the locations for the first and second aligning positions for the aligning members
141 and 142 may be changed depending on the type of the stapling mode.
[0145] Figure 31 depicts the sheet alignment boundary in the two point stapling mode, and
Figure 32 depicts the sheet alignment boundary in the angled rear stapling mode. Figure
33 depicts the sheet alignment boundary in the angled front stapling mode. In the
drawings, the double dot chain line outlines the first sheet alignment boundary, and
the solid line outlines the second sheet alignment boundary. When the sheet alignment
boundary is on the front side relative to where discharged sheets land in the processing
tray 130, the rear aligning member 142 shifts the sheets toward the front aligning
member 141 which serves as the alignment reference, and when the sheet alignment boundary
is on the rear side relative to where the sheets land in the processing tray 130,
the sheets are aligned in the manner described before.
[0146] By varying the sheet alignment boundary depending on the stapling mode as described
above, sheets can be moved to a location where the sheets can be properly stapled
by the stapler 101.
[0147] As is evident from the above description, according to the present invention, the
sheet alignment boundary, into which the sheets discharged into the processing tray
130 by the discharge roller pair 7 are converged by the aligning members 141 and 142,
is switched for each set between two locations. Therefore, when two or more sets of
sheets are processed, they are stacked in a staggered arrangement in the stacking
tray 200 as they are discharged from the processing tray 130 into the stacking tray
200, eliminating the need for shifting the stacking tray 200 to stagger the sheet
sets. In other words, it is unnecessary to shift the stacking tray 200 in order to
cause an incoming set of sheets to stagger relative to the immediately preceding set
as it is discharged into the stacking tray 200. Thus, damages such as scratches or
buckling which are liable to occur to sheet edges due to the friction which occurs
when the stacking tray 200 is shifted in the alternate directions while holding a
large number of sheets do not occur; the quality of the discharged sheets can be maintained.
[0148] Further, a motor and a mechanism for shifting the stacking tray 200 with large capacity
is unnecessary, and therefore, the apparatus size can be reduced.
[0149] Next, the movements of the stacking tray 200 and the sampling tray 201 will be described
with reference to Figures 8 and 9. Normally, before activation, each tray remains
on standby at a point next to the sheet surface detection sensor correspondent to
each tray.
[0150] As described before, the normal tray in which copies or the output of a printer are
stacked is the stacking tray 200. It receives the copies or the output after they
are processed by a processing device such as the aforementioned stapler 101. Also,
it receives such sheets that are discharged in the form of an unbound set which is
constituted of a relatively small number of sheets. The maximum capacity of the stacking
tray 200 is the weight equivalent to 2,000 ordinary sheets, and whether or not the
current weight of the sheets in the stacking tray 200 is at the limit of the stacking
tray 200 is monitored through the sensor S203d.
[0151] If a single image forming job does not end even though the stacking tray 200 is already
at a position next to the sensor S203d, the stacking tray 200 is lowered a distance
equivalent to the weight of 1,000 ordinary sheets, that is, to a position next to
the sensor S203d'. Then, the sampling tray 201 is lowered to the position next to
the sheet surface sensor S205 for the processing tray 130, and sheet reception is
restarted, this time, into the sampling tray 201. At this time, the sampling tray
201 can take a maximum weight equivalent to 1,000 ordinary sheets, and whether or
not the current weight of the sheets in the sampling tray 201 is at the limit of the
sampling tray 201 is monitored through the sensor S203c.
[0152] There are times when the second job is started without removing the sheets on the
stacking tray 200 after the first job, the output of which is no more than 2,000 ordinary
sheets in terms of weight, or when a current job must be interrupted to perform another
job. At such times, the output may be discharged into the sampling tray 201 through
the non-sorting path, although the output cannot be processed.
[0153] As for the normal modes in which the output from the apparatus main assembly is discharged
into the sampling tray 201 through the non-sorting path 21, there are a mode in which
a single set of sheets are discharged as a sample, a functional sorting mode in which
the sampling tray 201 is designated as the output tray, and the like modes.
[0154] Next, the hole punching mode will be described following the flow chart given in
Figure 34, concentrating on the operational sequence of the hole punching unit 50.
[0155] As the power source of the apparatus is turned on (S1), the hole punching means moving
motor is activated, and moves the hole punching means 60 in the direction of an arrow
mark E in Figure 13. As a result, the light receptor portion 71a of the hole punching
means initial position detection sensor 71 is blocked by the hole punching means initial
position marker 52, in other words, the initial position of the hole punching means
60 is detected, and the hole punching means is stopped.
[0156] At the same time, the lateral edge detection means moving motor is also activated
to move the sensor arm 82 in the arrow E direction. As a result, the light receptor
portion 84a of the lateral edge detection sensor 84 is blocked by the lateral edge
initial position marker 63b provided on the casing 63, in other words, the initial
position for the hole punching means 60 is detected (S3), and the hole punching means
60 remains on standby at the initial position to wait for an input (S3).
[0157] Next, an operator is to press an unillustrated hole punching mode selection button,
and press an unillustrated start button (S4). Then, sheets begin to be conveyed, and
image formation begins in the main assembly of the image forming apparatus (S6).
[0158] At the same time, the lateral edge detection means moving motor is activated, moving
the sensor arm 82 in the arrow D direction until the lateral edge detection sensor
81 arrives at a position correspondent to the selected sheet size (S5).
[0159] Then, a sheet with a finished image is conveyed into the finisher 1. As the leading
edge of the sheet passes by the sheet detection sensor 31, it is detected by the sheet
detection sensor 31, and after a predetermined delay, the hole punching means moving
motor is activated, moving the hole punching means 60 and the lateral edge detection
sensor 81 in the arrow D direction until the light receptor portion 81a of the lateral
edge detection sensor 81 is blocked by the lateral edge of the sheet. As the receptor
portion 81a is blocked by the sheet edge, the motor is deactivated (S8).
[0160] Next, as the trailing edge of the sheet passes by the sheet detection sensor 31,
it is detected by the sheet detection sensor 31 (S9), and after a predetermined delay,
the hole punching mean driving motor 66 is activated, rotating the punch 61 and the
die 62 in the arrows B and C directions, respectively. Then, as the punch 61 engages
in the hole 62a of the die 62, a hole is punched in the sheet, which is being conveyed
through the hole punching means 60 (S10). Thereafter, the sheet is delivered to the
path correspondent to the sheet processing mode selected from a list of sheet processing
modes such as those mentioned above.
Embodiment 2
[0161] In the first embodiment, sheets are discharged into the processing tray 130, and
aligned there, after the position of the aligning member 141 or 142, which is to serve
as the sheet alignment reference, is changed. However, sheets may be aligned first,
and then shifted to a location different from the location to which the immediately
preceding set of sheets is shifted, before it is discharged from the processing tray
130.
[0162] Referring to Figure 36, in this embodiment, after being discharged into the processing
tray 130, a relatively small number of sheets, or a sub-set of sheets, is placed squarely
in contact with an aligning reference wall 401 by an aligning wall 141, becoming aligned
at a location Pa. As soon as the aligning of a predetermined, relatively small, number
of sheets is completed, the aligning reference wall 401 is rotated by the function
of a solenoid (unillustrated) to a position below the processing tray 130 as illustrated
in Figure 37.
[0163] Then, the sub-set of the aligned sheets is pushed a predetermined distance by the
aligning wall 141, to a location Pb. Then, the oscillating guide 150 is lowered onto
the sheets, and discharges the set of the aligned sheets into the stacking tray 200.
After all the sheets in the currently processed set are discharged, the sheets of
the next set are discharged from the location Pa, without being shifted to the location
Pb, so that they are stacked in a staggered arrangement relative to the sheets in
the immediately preceding set as they are discharged into the stacking tray 200.
[0164] While the invention has been described with reference to the structures disclosed
herein, it is not confined to the details set forth, and this application is intended
to cover such modifications or changes as may come within the purposes of the improvements
or the scope of the following claims.
[0165] A sheet processing apparatus includes a first stacker for stacking sheets discharged
thereto; a feeder for feeding a set of sheets from the first stacker; a second stacker
for stacking the set of sheets fed by the feeder; a shifting device for shifting the
sheets stacked on the first stacker; a controller for grouping the sheet in a set
into a plurality of groups of sheets, and stacking, shifting and feeding the sheets,
for each group, to the first stacker, and for stacking the set of sheets on the second
stacker.
1. A sheet processing apparatus comprising:
first stacking means for stacking sheets discharged thereto;
feeding means for feeding a set of sheets from said first stacking means;
second stacking means for stacking the set of sheets fed by said feeding means;
shifting means for shifting the sheets stacked on said first stacking means;
control means for grouping the sheet in a set into a plurality of groups of sheets,
and stacking, shifting and feeding the sheets, for each group, to said first stacking
means, and for stacking the set of sheets on said second stacking means
2. A sheet processing apparatus comprising:
first stacking means for stacking sheets discharged thereto;
feeding means for feeding a set of sheets from said first stacking means;
second stacking means for stacking the set of sheets fed by said feeding means;
shifting means for shifting the sheets stacked on said first stacking means;
control means for grouping the sheet in a set into a plurality of groups of sheets,
and stacking, shifting and feeding the sheets, for each group, to said first stacking
means, and for stacking the set of sheets on said second stacking means, said control
means controlling said shifting means to stack a set of sheets and a set of sheets
at offset positions on said stacking means.
3. An apparatus according to Claim 2, wherein said shifting means functions also as means
for aligning the sheets.
4. An apparatus according to Claim 3, wherein said aligning means includes a pair of
aligning members for shifting the sheets in a direction crossing with a direction
of sheet discharge, wherein one of said aligning members are set at different positions
for the set of sheets and the set of sheets, and the other aligning member moves,
for each discharge of sheet, to urge the sheet to said one of aligning members.
5. An apparatus according to Claim 3, wherein said aligning means includes a pair of
aligning members for shifting the sheets in a direction crossing with a direction
of sheet discharge, wherein one of said aligning members is set at an aligning position
or is retracted from the aligning position, the other aligning member moves, for each
discharge of sheet, to urge the sheet to said one of aligning members placed at the
aligning position, and wherein said aligning means, after its alignment operation,
retracts said one of said aligning members and shifts the set of sheets or retaining
said one of said aligning members at the aligning position, in accordance with whether
the set of sheets is the set of sheets or the second set of sheets.
6. An apparatus according to Claim 4, wherein said second stacking means is disposed
downstream of said first stacking means, and said first and second stacking means
are inclined such that downstream sides thereof take upper positions, and wherein
said second stacking means lowers in accordance with an amount of the sets of sheets
stacked thereon.
7. An apparatus according to Claim 5, wherein said second stacking means is disposed
downstream of said first stacking means, and said first and second stacking means
are inclined such that downstream sides thereof take upper positions, and wherein
said second stacking means lowers in accordance with an amount of the sets of sheets
stacked thereon.
8. An apparatus according to Claim 1, wherein said feeding means includes a pair of rotatable
members and is openable such that it opens when the sheet is discharged to said first
stacking means, and feeds the set of sheets to said second stacking means.
9. An apparatus according to Claim 6, wherein said feeding means includes a pair of rotatable
members and is openable such that it opens when the sheet is discharged to said first
stacking means, and feeds the set of sheets to said second stacking means.
10. A sheet processing apparatus comprising:
first stacking means for stacking sheets discharged thereto;
feeding means for feeding a set of sheets from said first stacking means;
second stacking means for stacking the set of sheets fed by said feeding means;
aligning means for aligning the sheets stacked on said first stacking means;
control means for grouping the sheet in a set into a plurality of groups of sheets,
and stacking, aligning and feeding the sheets, for each group, to said first stacking
means, and for stacking the set of sheets on said second stacking means.
11. An apparatus according to Claim 10, wherein said control means controlling said shifting
means to stack a set of sheets and a set of sheets at offset positions on said stacking
means.
12. An apparatus according to Claim 11, wherein said aligning means includes a pair of
aligning members for shifting the sheets in a direction crossing with a direction
of sheet discharge, wherein one of said aligning members are set at different positions
for the set of sheets and the set of sheets, and the other aligning member moves,
for each discharge of sheet, to urge the sheet to said one of aligning members.
13. An apparatus according to Claim 11, wherein said aligning means includes a pair of
aligning members for shifting the sheets in a direction crossing with a direction
of sheet discharge, wherein one of said aligning members is set at an aligning position
or is retracted from the aligning position, the other aligning member moves, for each
discharge of sheet, to urge the sheet to said one of aligning members placed at the
aligning position, and wherein said aligning means, after its alignment operation,
retracts said one of said aligning members and shifts the set of sheets or retaining
said one of said aligning members at the aligning position, in accordance with whether
the set of sheets is the set of sheets or the second set of sheets.
14. An apparatus according to Claim 12, wherein said second stacking means is disposed
downstream of said first stacking means, and said first and second stacking means
are inclined such that downstream sides thereof take upper positions, and wherein
said second stacking means lowers in accordance with an amount of the sets of sheets
stacked thereon.
15. An apparatus according to Claim 10, wherein said second stacking means is disposed
downstream of said first stacking means, and said first and second stacking means
are inclined such that downstream sides thereof take upper positions, and wherein
said second stacking means lowers in accordance with an amount of the sets of sheets
stacked thereon.
16. An apparatus according to Claim 14, wherein said feeding means includes a pair of
rotatable members and is openable such that it opens when the sheet is discharged
to said first stacking means, and feeds the set of sheets to said second stacking
means.
17. An apparatus according to Claim 15, wherein said feeding means includes a pair of
rotatable members and is openable such that it opens when the sheet is discharged
to said first stacking means, and feeds the set of sheets to said second stacking
means.
18. An apparatus according to Claim 3 or 11, further comprising binding means for binding
the set of sheets on said first stacking means, and the aligning position of said
aligning means are different in an operation mode wherein the sheets are bound and
in an operation mode wherein the sheets are not bound by said binding means.
19. An apparatus according to Claim 4 or 12, wherein the aligning positions are changed
in accordance with to positions corresponding to binding positions where said binding
means binds the sheets.
20. An apparatus according to Claim 19, wherein the binding positions includes positions
for two-position stapling and one position stapling.
21. An apparatus according to Claim 1 or 9, further comprising a temporary stacking portion
for temporarily stacking a plurality of sheets in a sheet passage before said first
stacking means, wherein after the set of sheets on said first stacking means is discharged,
the set of sheets on said temporary stacking means are discharged to said first stacking
means.
22. An image forming apparatus comprising a sheet processing apparatus as defined in any
one of preceeding claims, comprising means for forming an image on the sheets, which
is discharged to said first stacking means.