U.S. patent number RE36,923 [Application Number 08/506,957] was granted by the patent office on 2000-10-24 for sheet stapler.
This patent grant is currently assigned to Canon Kabushiki Kaisha. Invention is credited to Masakazu Hiroi, Koichi Murakami, Yuji Takahashi.
United States Patent |
RE36,923 |
Hiroi , et al. |
October 24, 2000 |
**Please see images for:
( Certificate of Correction ) ** |
Sheet stapler
Abstract
A sheet stapling apparatus including a stapling device for
stapling a set of sheets, a load detecting device for detecting a
level of a load of the stapling device during a stapling operation,
and a signal generating device for generating a signal when the
load detected by the load detecting device is outside a
predetermined range.
Inventors: |
Hiroi; Masakazu (Yokohama,
JP), Murakami; Koichi (Yokohama, JP),
Takahashi; Yuji (Tokyo, JP) |
Assignee: |
Canon Kabushiki Kaisha (Tokyo,
JP)
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Family
ID: |
26557981 |
Appl.
No.: |
08/506,957 |
Filed: |
July 27, 1995 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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830526 |
Feb 4, 1992 |
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698339 |
May 7, 1991 |
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271424 |
Nov 15, 1988 |
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Reissue of: |
007033 |
Jan 21, 1993 |
05230457 |
Jul 27, 1993 |
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Foreign Application Priority Data
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Nov 16, 1987 [JP] |
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62-290293 |
Dec 2, 1987 [JP] |
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62-305407 |
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Current U.S.
Class: |
227/2; 227/131;
227/6; 399/410 |
Current CPC
Class: |
B27F
7/23 (20130101); B27F 7/36 (20130101); B27F
7/38 (20130101) |
Current International
Class: |
B27F
7/38 (20060101); B27F 7/36 (20060101); B27F
7/00 (20060101); B27F 007/36 () |
Field of
Search: |
;227/2,5,6,7,131
;355/323,324 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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245086 |
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Nov 1987 |
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EP |
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3726406 |
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Feb 1988 |
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DE |
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50-1318 |
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Jan 1975 |
|
JP |
|
54-42086 |
|
Apr 1979 |
|
JP |
|
1003623 |
|
Sep 1965 |
|
GB |
|
1358212 |
|
Jul 1974 |
|
GB |
|
2010957 |
|
Jul 1979 |
|
GB |
|
2187174 |
|
Sep 1987 |
|
GB |
|
2189906 |
|
Nov 1987 |
|
GB |
|
Primary Examiner: Smith; Scott A.
Attorney, Agent or Firm: Fitzpatrick, Cella, Harper &
Scinto
Parent Case Text
This application is a continuation of application Ser. No.
07/830,526 filed Feb. 4, 1992, which is a continuation of
application Ser. No. 07/698,339 filed May 7, 1991, which is a
continuation application of Ser. No. 07/271,424 filed Nov. 15,
1988, now all abandoned.
Claims
What is claimed is:
1. A sheet stapling apparatus, comprising:
stapling means, movable from a home position to a stapling
position, for stapling a set of sheets, said stapling means
including a hammer for driving a staple into the set of sheets;
driving means for driving said stapling means toward the stapling
position, said driving means including an electrical driving means
for supplying power to said hammer;
load detecting means for detecting a current load of said
electrical driving means during a stapling operation, and for
generating a signal when the load detected by said load detecting
means is outside of a predetermined level; and
control means for controlling said driving means to move said
stapling means toward the home position when the load detected by
said load detecting means is not less than a predetermined level,
wherein
said load detecting means detects the level of the load by
detecting a level of current through said electrical driving
means.
2. An apparatus according to claim 1, wherein said load detecting
means produces the signal when the current is not higher than the
predetermined level.
3. An apparatus according to claim 2, further comprising feeding
means for feeding staples toward said stapling means in a feeding
operation in response to each stapling operation by said stapling
means, and wherein said control means is responsive to a signal
generated by said load detecting means and repeats the stapling
operation by said stapling means and the feeding operation by said
feeding means.
4. A sheet stapling apparatus, comprising:
stapling means for stapling a set of sheets, said stapling means
including a hammer movable from a home position to a staple
position for driving a staple into the set of sheets, and driving
means for driving said hammer, said driving means including an
electrical driving means for supplying power to said hammer .[.and
being driven by a predetermined current.].;
load detecting means for detecting a .[.current.]. load of said
electrical driving means during a stapling operation, and for
generating a signal when the load detected by said load detecting
means is over .[.the.]. .Iadd.a .Iaddend.predetermined
.[.current.]..Iadd. limit.Iaddend.; and
control means for controlling movement of said driving means to
.Iadd.perform reverse driving of said hammer to .Iaddend.return
said hammer to the home position when said detecting means
generates the signal.
5. An apparatus according to claim 4, wherein said detecting means
includes a detector for detecting the load on the basis of a
stapling speed of said stapling means, and for discriminating that
the .[.current.]. load is a light load without a staple, when the
stapling speed is higher than a predetermined level.
6. An apparatus according to claim 4, wherein said detecting means
includes a detector for detecting the load on the basis of stapling
acceleration of said stapling means, and for discriminating that
the .[.current.]. load is a light load without a staple, when the
stapling acceleration is higher than a predetermined level.
7. An apparatus according to claim 4, wherein said detecting means
includes means for detecting the load on the basis of an end of one
cycle of operation of said stapling means and for discriminating
that the .[.current.]. load is a light load without a staple, when
the end of one cycle occurs within a predetermined period.
8. An apparatus according to claim 4, wherein said detecting means
detects
an .[.overloaded current.]. .Iadd.overload .Iaddend.on the basis of
stapling speed of said stapling means, and discriminates .[.that.].
the .[.current is overloaded.]. .Iadd.overload .Iaddend.when the
stapling speed is lower than a predetermined level.
9. An apparatus according to claim 4, wherein said detecting means
detects an .[.overloaded current.]. .Iadd.overload .Iaddend.on the
basis of stapling acceleration of said stapling means, and
discriminates .[.that.]. the .[.current is overloaded.].
.Iadd.overload .Iaddend.when the stapling acceleration is lower
than a predetermined level.
10. An apparatus according to claim 4, wherein said detecting means
detects an .[.overloaded current.]. .Iadd.overload .Iaddend.on the
basis of an end of one cycle of operation of said stapling means
and discriminates .[.that.]. the .[.current is overloaded.].
.Iadd.overload .Iaddend.when the end of one cycle does not occur
within a predetermined period.
11. A sheet stapling apparatus, comprising:
stapling means for stapling a set of sheets, said stapling means
including a hammer movable from a home position to a staple
position for driving a staple into the set of sheets, and driving
means for driving said hammer, said driving means including an
electrical driving means for supplying power to said hammer .[.and
being driven by a predetermined current.].;
detecting means for detecting a light .[.current.]. load of said
electrical driving means when a .[.current.]. .Iadd.load
.Iaddend.applied to said electrical driving means is less than
.[.the.]. .Iadd.overload .Iaddend.predetermined .[.current.].
.Iadd.limit .Iaddend.during a stapling operation .Iadd.by the
arrival of said hammer to the home position within a predetermined
time.Iaddend.; and
control means for controlling said driving means to .[.return.].
.Iadd.repeat the stapling operation after .Iaddend.said hammer
.Iadd.returns .Iaddend.to the home position, when said detecting
means detects a light load, and then repeating the stapling
operation.
12. An apparatus according to claim 11, wherein said detecting
means includes a detector for detecting the load on the basis of a
stapling speed of said stapling means, and for discriminating that
the .[.current.]. load is a light load without a staple, when the
stapling speed is higher than a predetermined level.
13. An apparatus according to claim 11, wherein said detecting
means includes a detector for detecting the load on the basis of
stapling acceleration of said stapling means, and for
discriminating that the .[.current.]. load is a light load without
a staple, when the stapling acceleration is higher than a
predetermined level.
14. An apparatus according to claim 11, wherein said detecting
means includes means for detecting the load on the basis of an end
of one cycle of operation of said stapling means, and for
discriminating that the .[.current.]. load is a light load without
a staple, when the end of one cycle occurs within a predetermined
period.
15. An apparatus according to claim 11, wherein said detecting
means detects an overloaded .[.current.]. of said stapling means
when a current applied to said electrical driving means is higher
than the predetermined current during a stapling operation of said
stapling means, and wherein said control means controls said
driving means to return said hammer to the home position when the
overloaded current is detected.
16. A sheet stapling apparatus, comprising:
stapling means, reciprocable between a home position and a stapling
position, for stapling a set of sheets, with said stapling means
including a hammer for driving a staple into the set of sheets;
driving means for reciprocating said stapling means in a direction
toward the stapling position, said driving means including an
electrical driving means for supplying power to said hammer;
load detecting means for detecting a current load of said
electrical driving means during a stapling operation and for
generating a signal when the load detected by said load detecting
means is outside of a predetermined level,
control means for controlling said driving means to move said
stapling means toward the home position when the load detected by
said load detecting means is not less than a predetermined level,
wherein
said load detecting means detects the current load by detecting
either one of the level of current and a voltage of said electrical
driving means.
17. A sheet stapling apparatus, comprising:
stapling means for stapling a set of sheets, with said stapling
means including a hammer reciprocable between a home position and a
stapling position for driving a staple, and driving means for
reciprocating said hammer in a direction toward the stapling
position, said driving means including an electrical driving means
for supplying power to said hammer and being driven by a
predetermined current;
detecting means for detecting an overloaded current of said
electrical driving means when a current applied to said electrical
driving means is higher than the predetermined current during a
stapling operation; and
control means for controlling said driving means to return said
hammer to the home position when said detecting means detects the
overload.
18. A sheet stapling apparatus for use with a sorter coupled with a
copying machine, comprising:
stapling means, movable from a home position to a stapling
position, for stapling a set of sheets, said stapling means
including a hammer for driving a staple into the set of sheets;
driving means, including an electrical driving means for supplying
power to said hammer, for driving said stapling means;
load detecting means for detecting a current load of said
electrical driving means during a stapling operation, and for
generating a signal when the load detected by said load detecting
means is outside of a predetermined level; and
control means for controlling said driving means to move said
stapling means toward the home position when the load detected by
said load detecting means is not less than a predetermined level,
wherein
said load detecting means detects the current load by detecting
either one of a level of a current and a voltage of said electrical
driving means.
19. A sheet stapling apparatus for use with a sorter coupled with a
copying machine, comprising:
stapling means for stapling a set of sheets, said stapling means
including a hammer movable from a home position to a stapling
position for driving a staple into the set of sheets, and driving
means for driving said hammer, said driving means including an
electrical driving means for supplying power to said hammer and
being driven by a predetermined current;
detecting means for detecting an overloaded current of said
electrical driving means when a current applied to said electrical
driving means is higher than the predetermined current during a
stapling operation; and
control means for controlling said driving means to return said
hammer to the home position when said detecting means detects the
overload.
20. A sheet stapling apparatus for use with a sorter coupled with a
copying machine, comprising:
stapling means for stapling a set of sheets, said stapling means
including a hammer movable from a home position to a stapling
position for driving a staple into the set of sheets, and driving
means for driving said hammer, said driving means including an
electrical driving means for supplying power to said hammer and
being driven by a predetermined current;
detecting means for detecting a light current load of said
electrical driving means when a current applied to said electrical
driving means is less than the predetermined current during a
stapling operation; and
control means for controlling said driving means to return said
hammer to the home position when said detecting means detects the
light load, and then repeating the stapling operation.
21. In a sorter coupled with a copying machine and having an
automatic sheet stapling apparatus comprising:
stapling means, movable from a home position to a stapling
position, for stapling a set of sheets including a hammer for
driving a staple into the set of sheets;
driving means, including an electrical driving means for supplying
power to said hammer, for driving said stapling means;
load detecting means for detecting a current load of said
electrical driving means during a stapling operation, and for
generating a signal when the load detected by said load detecting
means is outside of a predetermining level; and
control means for controlling said driving means to move said
stapling means toward the home position when the load detected by
said load detecting means is not less than a predetermined level,
wherein
said load detecting means detects the current load by detecting
either one of a level of a current and a voltage of said electrical
driving means.
22. In a sorter coupled with a copying machine and having an
automatic sheet stapling apparatus comprising:
stapling means for stapling a set of sheets, said stapling means
including a hammer movable from a home position to a stapling
position for driving a staple into the set of sheets, and driving
means for driving said hammer, said driving means including an
electrical driving means for supplying power to said hammer and
being driven by a predetermined current:
detecting means for detecting an overloaded current of said
electrical driving means when a current applied to said electrical
driving means is higher than the predetermined current during a
stapling operation; and
control means for controlling said driving means to return said
hammer to the home position when said detecting means detects the
overload.
23. In a sorter coupled with a copying machine and having an
automatic sheet stapling apparatus comprising:
stapling means for stapling a set of sheets, said stapling means
including a hammer movable from a home position to a stapling
position for driving a staple into the set of sheets, and driving
means for driving said hammer, said driving means including an
electrical driving means for supplying power to said hammer and
being driven by a predetermined current;
detecting means for detecting a light current load of said
electrical driving means when a current applied to said electrical
driving means is less than the predetermined current during a
stapling operation; and
control means for controlling said driving means to return said
hammer to the home position when said detecting means detects the
light load, and then repeating the stapling operation.
24. In a finisher coupled with a copying machine and having an
automatic sheet stapling apparatus comprising:
stapling means, movable from a home position to a stapling
position, for stapling a set of sheets, said stapling means
including a hammer for driving a staple into the set of sheets;
driving means, including an electrical driving means for supplying
power to said hammer, for driving said stapling means;
load detecting means for detecting a current load of said
electrical driving means during a stapling operation, and for
generating a signal when the load detected by said load detecting
means is outside a predetermined level; and
control means for controlling said driving means to move said
stapling means toward the home position when the load detected by
said load detecting means is not less than a predetermined level,
wherein
said load detecting means detects the current load by detecting
either one of a level of a current and a voltage of said electrical
driving means.
25. In a finisher coupled with a copying machine and having an
automatic sheet stapling apparatus comprising:
stapling means for stapling a set of sheets, said stapling means
including a hammer movable from a home position to a stapling
position for driving a staple into the set of sheets, and driving
means for driving said hammer, said driving means including an
electrical driving means for supplying power to said hammer and
being driven by a predetermined current;
detecting means for detecting an overloaded current of said
electrical driving means when a current applied to said electrical
driving means is higher than the predetermined current during a
stapling operation; and
control means for controlling said driving means to return said
hammer to the home position when said detecting means detects the
overload.
26. In a finisher coupled with a copying machine and having an
automatic sheet stapling apparatus comprising:
stapling means for stapling a set of sheets, said stapling means
including hammer movable from a home position to a stapling
position for driving a staple into the set of sheets, and driving
means for driving said hammer, said driving means including an
electrical driving means for supplying power to said hammer and
being driven by a predetermined current;
detecting means for detecting a light current load of said
electrical driving means when a current applied to said electrical
driving means is less than the predetermined current during a
stapling operation thereby; and
control means for controlling said driving means to return said
hammer to the home position when said detecting means detects the
light load, and then repeating the stapling operation.
27. In a sorter coupled with a copying machine and having a sheet
stapling apparatus, comprising:
stapling means for stapling a set of sheets, said stapling means
including a hammer movable from a home portion to a stapling
position for driving a staple into the set of sheets, And driving
means for driving said hammer, said driving means including an
electrical driving means for supplying power to said hammer and
being driven .[.by.]. .Iadd.according to .Iaddend.a predetermined
.[.current.]..Iadd.limit.Iaddend.;
load detecting means for detecting a .[.current.]. load of said
electrical driving means during a stapling operation, and for
generating a signal when the load detected by said load detecting
means is over the predetermined .[.current.]..Iadd.limit.Iaddend.;
and
control means for controlling movement of said driving means to
return said hammer to the home position when said detecting means
generates the signal.
28. An apparatus according to claim 27, wherein said detecting
means detects an .[.overloaded current.]. .Iadd.overload
.Iaddend.on the basis of an end of one cycle of operation of said
stapling means and discriminates .[.that.]. the .[.current is
overloaded.]. .Iadd.overload .Iaddend.when the end of one cycle
does not occur within a predetermined period.
29. In a finisher coupled with a copying machine and having a sheet
stapling apparatus, comprising:
stapling means for stapling a set of sheets, said stapling means
including a hammer movable from a home position to a staple
position for driving a staple into the set of sheets, and driving
means for driving said hammer, said driving means including an
electrical driving means for supplying
power to said hammer and being driven .[.by.]. .Iadd.according to
.Iaddend.a predetermined .[.current.]..Iadd.limit.Iaddend.;
load detecting means for detecting a .[.current.]. load of said
electrical driving means during a stapling operation, and for
generating a signal when the load detected by said load detecting
means is over the predetermined .[.current.]..Iadd.limit.Iaddend.;
and
control means for controlling movement of said driving means to
return said hammer to the home position when said detecting means
generates the signal.
30. An apparatus according to claim 29, wherein said detecting
means detects an .[.overloaded current.]. .Iadd.overload
.Iaddend.on the basis of an end of one cycle of operation of said
stapling means and discriminates .[.that the current is
overloaded.]. .Iadd.the overload .Iaddend.when the end of one cycle
does not occur within a predetermined period. .Iadd.31. A sorter
according to claim 27, wherein said load detecting means detects
the load of the electrical driving means on the basis of the
angular acceleration of said driving means..Iaddend..Iadd.32. A
sorter according to claim 27, wherein said load detecting means
detects the load of said electrical driving means on the basis of
the electrical current used by said electrical driving
means..Iaddend..Iadd.33. A finisher according to claim 29, wherein
said load detecting means detects the load of the electrical
driving means on the basis of the angular acceleration of said
driving means..Iaddend..Iadd.34. A finisher according to claim 29,
wherein said load detecting means detects the load of said
electrical driving means on the basis of the electrical current
used by said electrical driving means..Iaddend.
Description
FIELD OF THE INVENTION AND RELATED
The present invention relates to a sheet stapler for stapling
sheets.
An example of a conventional electric stapler is disclosed in U.S.
Pat. No. 4,573,625, and comprises a staple cartridge containing a
number of staples connected in the form of a belt or strip, a
stapling section for stapling the sheets with the staples and a
driver such as a motor for driving the stapling section, wherein
the sheets brought into the stapling section are stapled using the
motor.
However, the electric stapler disclosed in U.S. Pat. No. 4,573,625
is not provided with any detecting means for detecting staple jam,
a blank shot resulting from failure of the staple feed or the
like.
The driver in the form of a motor or the like of the electric
stapler is occasionally imposed with a load beyond its capacity and
is stopped sometimes, when, for example, to many sheets are
attempted to be stapled at once, when a staple shoots an already
stapled portion, or when thick or hard sheets are stapled. In this
case, the stapler is stopped while gripping the sheets, and
therefore, the operator has to manipulate the driver to release the
gripped sheets, thus requiring cumbersome work. Particularly, when
the stapler is operated with a sorter or the like for continuously
processing the sheets, the continuous processing operation is
interrupted by the stopping of the stapler, and therefore, the
operational efficiency is decreased.
In such a stapler, a leading edge of a strip of a series of staples
does not reach the stapling means immediately after the staple
cartridge is exchanged, and therefore, the stapling operation is
not possible, if the stapler is operated as it is. Therefore, the
operator has to carry out a pre-feeding operation in which the
blank shots are repeated several times until the leading edge of
the strip comes to the stapling position. The pre-feeding operation
is tiring work in which the stapling switch is simply repeatedly
depressed. In addition, it is unknown to the operator how many
blank shots are required, and therefore, the blank shots have to be
executed with some sheets set in the stapling station, since
otherwise the staple jam will occur. Thus, the pre-feeding
operation is very cumbersome.
The blank shot can occur by a malfunctioning of the staple feeding
means. Particularly, when the blank shot occurs in a stapler
interrelated with an image forming apparatus such as a copying
machine to sequentially staple sets of sheets discharged therefrom,
the sheets can be scattered or can be jammed.
SUMMARY OF THE INVENTION
Accordingly, a principal object of the present invention is to
provide a stapler provided with means for detecting malfunction of
the a staple such as a staple jam or a blank shot.
It is another object of the present invention to provide a stapler
wherein a predetermined overload of the driver for the stapler is
detected, and the driver drives in a reversed direction before the
driver stops to retract the stapling station, by which the problems
described above are eliminated.
According to the present invention, there is provided a stapler
comprising staples for stapling sheets, a hammer movable between a
stapling position for stapling the sheets and a non-operative
position, a driver for driving the hammer, an overload detecting
means for detecting a predetermined overload produced in the driver
for the hammer, and reversing means, responsive to detection by
said overload detecting means, for reversing the driver to retract
the hammer from the stapling position to the non-operative
position.
In this stapler, when the sheets are set in the stapling position,
the hammer is moved and staples the sheets. Upon the stapling
operation by the hammer, if the driver for the hammer is imposed
with a load which is larger than a predetermined load, for example,
more than a tolerable number of sheets being set, the overload is
detected by the overload detecting means. In response to the
detection, the driver is controlled by the reversing means, and is
rotated in the reverse direction to retract the staple hammer so
from the stapling position.
A further object of the present invention is to provide a stapler
wherein the cumbersome prefeeding operation is eliminated, or
wherein a problem resulting when the set of sheets to be stapled is
not actually stapled is corrected.
According to another embodiment of the present invention, there is
provided a stapler comprising means for sequentially stapling set
of sheets with a staple at a leading edge of a strip of staples,
and means for feeding the strip of staples by a predetermined
distance for each of the stapling actions, load detecting means for
detecting the load of the stapling means upon the stapling action,
and control means for allowing the stapling operation by said
stapling means and the feeding operation by said feeding means when
the load detected by the load detecting means is not more than a
predetermined load. Therefore, if a blank shot occurs, the stapling
operation is repeated until the sheets are actually stapled.
Accordingly, even when a fresh strip of needles are loaded, normal
operation begins and the pre-feeding operation is automatically
executed. Also, even if the blank shot occurs due to the
malfunction of the strip feeding, the stapling operation is
repeated until the staple is actually shot. Therefore, if the
malfunction of the feeding means is cleared in the subsequent
feeding, the stapling operation is performed without
interruption.
These and other objects, features and advantages of the present
invention will become more apparent upon 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
FIG. 1 is a block diagram illustrating a control of a stapler
according to an embodiment of the present invention.
FIGS. 2 and 3 illustrate structures of the stapler according to the
embodiment of the present invention.
FIGS. 4 and 5 illustrate major parts of the stapler.
FIG. 6 is a graph showing an output of a current sensor.
FIG. 7 is a flow chart illustrating the operation of the stapler
according to the embodiment of the present invention.
FIG. 8 is a graph showing a detection output of a reflection type
sensor.
FIG. 9 shows structures of a stapler according to another
embodiment of the present invention.
FIG. 10 is a graph showing a load in the stapling operation.
FIG. 11 is a block diagram illustrating the control system for the
stapler.
FIGS. 12 and 13 are flow charts illustrating the operation of the
stapler.
FIG. 14 shows structures of a stapler according to a further
embodiment of the present invention.
FIG. 15 is a block diagram of a control system of the stapler.
FIG. 16 is a graph showing a speed in the stapling operation of the
stapler.
FIG. 17 is a flow chart illustrating the operation of the
stapler.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring first to FIGS. 2 and 3, there are shown front and side
views of a stapler according to an embodiment of the present
invention. As shown in FIG. 2, the stapler 100 includes a base 1
which is fixed, a lower jaw 2 rotatable about a pin 2a and an upper
unit 3. At an end of the lower jaw 2, a channel-shaped cam 2b is
formed and is engaged with a cramping pin 3b fixed to the upper
unit 3. The upper unit 3 is swingably supported on a hinge pin 4
mounted to the base. A crank arm 5 is rotatably supported on a part
of base 1 by a pin 5b adjacent an end of the crank arm 5. The other
end thereof is engaged with a cam plate 5c fixedly and
eccentrically mounted to a drive shaft 6. When a stapler gear 7
rotates through one full turn, the cam plate 5c rotates about the
pin 6. At this time, since the base 1 is fixed, and since the
distance between the pin 5b and the pin 6 is constant, the upper
unit 3 rotates about the hinge pin 4 relative to the base 1. Also,
a body 8 is pushed by a head 105a of the driver mounted to the body
and is rotated in the direction x about the hinge pin 4 (the body 8
is rotatably supported by the hinge pin 4). Simultaneously, by the
channel cam 2b of the lower jaw 2 engaged with the cramping shaft
3b of the upper unit 3, the lower jaw 2 rotates in the direction Y
about the pin 2a. The base 1 is provided with an anvil 9 for
bending the legs of the staple toward each other.
Above the upper unit 3, there is a motor which is a driving source
for the stapler mechanism, the driving force thereof is transmitted
to a stapler gear 7 through a motor gear 11. A home position sensor
12 includes a microswitch for detecting the stapler 100 being
placed at its home position wherein the stapler 100 is waiting for
its operation, that is, the body 8 and the lower jaw 2 are spaced
apart. Together with the stapler gear 7 rotating through one full
turn, the sensor cam 13 rotates through one full turn, and a
projection 13b of the sensor cam 13 actuates the microswitch 12, by
which the home position of the stapler 100 is detected. Thus, one
full turn of the stapler gear 7 corresponds to one stroke of the
stapling operation. The motor 10 is supplied with driving current 5
through a wire 15.
Load detecting means in the form of a current sensor in this
embodiment detects the current through the wire 15. The current
sensor 16 is fixed on an unshown base.
Referring to FIG. 4, the stapler feeding and a stapling mechanism
will be described. FIG. 4 is a detailed sectional view of staple
feeding and staple bending stations in the body 8. Designated by a
reference 101 is staples, and individual staples are bonded at
their centers. To constitute a strip containing the staples, the
strip is accommodated in a cartridge 102. The mechanism includes
movement confining means fixed in the cartridge and is in the form
of a leaf spring and urges the strip of the staples to a guiding
portion 102a of the cartridge 102 with proper contact pressure,
thus guiding it. A driver or hammer 105 is effective to separate
the bonded staples one by one and penetrate it through the sheets
to reach the anvil 9. The head 105a of the driver 105 is in contact
with the upper unit 3 as described in the foregoing. Therefore,
when the upper unit 3 rotates, the driver head 105a is pushed
downwardly in a direction indicated by X1 in FIG. 4.
Referring to FIG. 4, the end edge 101a of the strip is held at its
central portion by the groove 109a of the staple bending block 109.
When the driver head 105a moves down, the bending block 110 for
bending the staple into a channel shape moves down simultaneously.
Thus, the block 110 abuts opposite ends of the staple, which is
actually in the form of a needle, and bends it into a channel shape
to form a staple. When the driver head 105a is further pushed, a
projection 110a of the bending block 110 pushes a staple feeding
member 104 (staple feeding means) rotatably supported on a pin
104a, by which the staple feeding member flexes a spring 104b to
move to a position indicated by chain lines. Then, a staple feeding
pawl 104a moves in a direction opposite to the staple feeding.
However, the first staple 101a has already been bent into the
channel shape, and therefore, it is not moved in the opposite
direction, and only the feeding pawl moves in that direction, so
that it is prepared for the next staple feeding operation.
Thereafter, the driver head 105a is moved further downwardly, a
block urging pawl 105b of the driver 5 is disengaged from the upper
part of the bending block 110, and only the driver 105 moves
downwardly. Thus, the leading edge 105a of the driver reaches a
tapered portion of the bending block 109. With further downward
movement thereof, it pushes the bending block 109 supported in the
opening 106a of the block guide 106 toward the position indicated
by the chain lines (flexing the confining spring 109), and
cooperates with a stapler cutter 108 to cut out the first staple
now bent into a channel shape, and penetrates the staple 101a into
the sheets. After the sheets are stapled in this manner, the driver
head 105a is returned to its upper position, and the projection
110a is disengaged from the member 104 and the needle feeding pawl
104a is returned to its home position. With this, the strip is
advanced.
The staple feeding and the stapling operations are performed
through this stroke.
FIG. 6 is a graph of a current through the motor 10 in one cycle of
the stapling operation, detected by the current sensor 16.
In this Figure, "a" indicates the current when the staple is
correctly fed and is correctly penetrated into the sheet; "b"
indicates the current upon blank shot in which no staple is
dispensed when the stapler is operated. Since with a blank shot,
there is no load for bending and penetrating the staple, the level
of the current is low; and "c" indicates the current upon
malfunction or staple jam or the like, in which an overload is
generally produced with the result of extremely high level of the
current.
In this embodiment, the stapling operation is deemed as being
normal when the current is 10 (initial set on level); when
I>IO+C(C: variation), it is deemed that staple jam, malfunction
of the stapling operation or a problem in the stapling mechanism
occurs; and when I<IO-C, it is deemed that the blank shot
occurs.
In FIG. 4, a reference numeral 201 designates a sensor for
detecting the presence or absence of the staples.
Referring now to FIG. 1 which is an electric block diagram, the
control of the stapler of this embodiment will be described.
The control system includes control means, or more particularly, a
control circuit 301 which is in this embodiment a known
microcomputer including a programmed sequential control. The
control circuit 301 is provided with output terminals A and B for
rotating the motor 10 in the forward and backward directions,
respectively. The outputs therefrom are transmitted to a
forward-reverse driver 302. When an output is produced at the
terminal A, a normal stapling operation is effected, whereas when
an output is produced at the terminal B, a reversed drive is
performed. When the stapler is at the home position, the home
position sensor 12 is in an on state, and it is transmitted to a
terminal C of the control circuit 301. Irrespective of whether the
motor is rotated in the forward or backward direction, when a
signal is produced from the home position sensor, both of the
terminals A and B of the control circuit 301 are rendered off, so
that the motor 10 stops. The lower jaw 2 of the stapler is always
placed adjacent the bottommost position as shown in FIG. 2, when
the motor 10 is stopped. Thus, the stapling operation is assured,
and the recovery work after the reverse rotation is made
easier.
An output of a reflection type sensor 701 is transmitted to a
terminal D of the control circuit 301 in the form of an analog
signal, and therefore, the microcomputer used has a function of
converting an analog signal to a digital signal.
A terminal E receives a detection signal from the current sensor
16. Since the detection signal of the current sensor 16 is in the
form of an analog signal, it is converted to a digital signal in
the control circuit 301. If the microcomputer not having such a
conversion function is used, an AD converter is used to provide the
microcomputer with a digitalized signal.
The control circuit 301 monitors the signal from the current sensor
16, that is, the current I through the motor. More particularly,
when Ip>IO+C, a problem in the stapling operation is deemed to
be occurring, whereas when Ip<IO-C, a blank shot is deemed to be
occurring, where Ip is a peak of the current between time t.sub.1
which is a predetermined period after start of the stapling
operation and time t.sub.2 which is a predetermined period after
the time t.sub.1.
Terminal F transmits a display signal to a display device 303 so
that the trouble in the stapling mechanism is displayed in response
to the display signal.
Referring to FIG. 7 which is a flow chart, the operation will be
described.
At step S1, start of the stapling operation is discriminated, at
step S2, the terminal A produces an on signal so that the motor is
rotated forwardly. At step S3, the discrimination is made as to
whether or not the predetermined period t.sub.1 has passed from the
start of the stapling operation. If so, the current I through the
motor 10 is monitored on the
basis of the input to the terminal E, at step S4 to determine the
peak current level Ip. At steps S5 and S6, the discrimination is
made as to whether or not the current level Ip is normal, that is,
whether or not the load of the motor is normal. If it is normal, at
step S7 the home position of the stapler is confirmed, and the
motor 10 is stopped.
If Ip>IO+C at step S5, that is, if the current level Ip is
excessively high, it means that staple jam or the like occurs.
Therefore, the output of the terminal A is rendered off, and the
output of the terminal B is rendered on to rotate the motor 10 in
the reverse direction at step S9.
Further, at step S10, the malfunction of the stapler is displayed
on the display device 303. At step S11, the home position of the
stapler is confirmed, and then the motor 10 is stopped. When the
stapler is not returned to the home position even if a
predetermined period T has passed after the reverse rotation of the
motor 10, it is discriminated that the stapler is stopped on its
way home by the staple jam, and therefore, the sequence goes from
the step S12 to the step S8 to stop the motor.
Another embodiment of the present invention will be described which
is advantageously usable with a general electric stapler, but it is
particularly advantageous when it is used in a finisher or a sorter
an automatic stapler connected with a copying machine or the
like.
In this embodiment, the current level in the stapling operation is
used for discrimination of the actual stapling or blank shot.
However, a voltage level of the motor may be used, and as another
alternative, a blank shot can be detected by a load cell 401 (FIG.
2) mounted to the stapler which is effective to discriminate
whether or not an impact load is produced.
As a further alternative means, use can be made with the reflection
type sensor 201 which is provided to detect the staples, and the
comparison is made between the waveform of the voltage level when
the staple is correctly fed and the waveform when the staple is
erroneously fed (FIG. 8). Upon normal feeding, the output from the
sensor is in the form of a wave shown in this Figure because the
output decreases at each of the seams. However, when the staple is
not fed correctly, the output from the sensor does not change.
Thus, erroneous stapling feeding can be detected.
When erroneous staple feed is discriminated, a trouble signal is
produced, and the apparatus is stopped, or it is possible that the
stapling operation is repeated, in consideration of the fact that
the failure of the staple feeding means with the high possibility
that the next staple does not reach the stapling position, and that
the next is a blank shot.
Referring to FIG. 9, a further embodiment of the present invention
will be described wherein a problem with the stapler mechanism is
detected using the home position sensor. In FIG. 9, the same
reference numerals as in FIG. 2 are assigned to the corresponding
elements. The force required for rotating the stapler gear 7 in
FIG. 9 changes as shown in FIG. 10. The force required in the time
period a.sub.2 until the penetration of the staple 109a through the
sheets S varies depending on the material, thickness and number of
the sheets S, and the maximum force W1 when the staple 109a
penetrates through the sheet S also changes. When, for example, the
maximum force W1 when the staple penetrates through the sheets S
exceeds a maximum force Wmax required for bending the legs of the
staple 109a by the anvil 9 and the hammer, there is a possibility
that it ca not be bent by the maximum power of the motor 10,
although the maximum force provided by the motor 10 is larger than
the maximum force Wmax. If that is the case, the motor 10
automatically stops. In this embodiment, before the stoppage of the
motor 10 rotation, the motor 10 is rotated reversely to retract the
driver 105 to avoid the stoppage of the motor.
In FIG. 10, reference a.sub.1 indicates the time period from the
start of the driver 105 to the arrival thereof on the surface of
the sheet S; a.sub.2 indicates the time period during which the
staple 109a is penetrating the sheets S; a.sub.3, a.sub.4 and
a.sub.5 are time periods from the penetration of the leading edges
of the legs of the staple 109a through the sheets S to the start of
the bending action by the anvil 9; and a.sub.6 the time period
required for the channel shaped staple 109a is bent flat by the
anvil 9.
Referring to FIG. 11, there is shown an electric circuit block
diagram of the stapler according to this embodiment of the present
invention. The control section includes a known microcomputer (CPU)
30 containing a program for sequential control and means 430a for
reversing the driver. The terminals A, B, C and D thereof are
connected to a forward-reverse driver 302, a microswitch 12 and
staple detecting sensor 201 or the like. The terminals A and B are
output terminals for supplying to the motor 10 a signal for
rotating the forward-reverse driver 302. When the output of the
terminal A is produced, the motor 10 is rotated forwardly to
execute the normal stapling operation, whereas when the output
terminal B is produced, a reverse operation is performed. When the
driver 105 is at a stand-by position, the microswitch 12, which is
a home position sensor, is closed, and the signal thereof is
inputted to the terminal C. The forward-reverse driver 302 is
constituted such that irrespective of whether the motor 10 is
rotated forwardly and reversely, it is instantaneously stopped in
response to actuation of the microswitch 12. When the motor is
stopped, the lower jaw 2 is always at the bottommost position shown
in FIG. 9. By this, the stapling operation is assured, and the
easiness of the recovery manipulation after the reverse rotation is
assured. To the terminal D a signal from the staple detecting
sensor 201 is supplied.
Referring to FIG. 12 which is a flow chart, operation of the
present embodiment will be described. When the start of the
stapling operation is detected (F1), a forward rotation signal is
supplied to the motor 12, so that the motor 10 rotates forwardly
(F2). The motor 10 drives the stapler gear 7, and the driver 105 is
moved to the stapling position by the driving force of the motor
10, where a staple 109a is shot to staple the sheets S, and
thereafter, the driver 105 is returned to the stand-by position.
During this, using a sensor cam 13 rotating in synchronism with the
stapler gear 7, the discrimination is made as to whether or not it
rotates from the home position (stand-by position) for actuating
the microswitch 12 and rotates through one full turn to return to
the home position within a predetermined period of time (0.8 sec,
for example) (F3). If so, that is, if it has returned within the
predetermined period of time T, the motor 10 is stopped, and the
operation is terminated in the normal manner (F4). If not, that is,
if the sensor cam 13 does not reach the home position even after
the passage of the predetermined period T, the motor 10 is rotated
reversely to return the driver 105 to the home position, that is,
to return the sensor cam 13 to its home position (F5).
The speed of the reverse rotation of the motor 10 is not required
to be so high as in the stapling operation, but may be lower than
that of the forward rotation.
When the driver 105 does not return to the stand-by position due to
some failure in the motor or the like even if the reverse rotation
of the motor 10 is instructed, the motor 10 is stopped, and a
trouble signal is produced to stop the stapler.
This embodiment has been described as a general electric stapler,
but it is applicable to a finisher or sorter with a stapler which
is connected to a copying machine, for example, to automatically
staple the sheets.
In this embodiment, the overload of the motor 10 is detected on the
basis of the time duration required for one cycle of the stapling
operation, but this is not limiting and it is a possible
alternative that the current through the driver such as a motor
when it drives the stapler is detected, and if it is higher than a
predetermined current, the overload of the driver is deemed as
occurring, in response to which the driver is reversed. A further
alternative is that the hammer mechanism for hammering the staple,
for example, a plunger or the like is provided with a pressure
sensor or the like, and when pressure exceeds a tolerable level,
the driver is rotated reversely.
Referring to FIG. 13, an example will be described wherein the
blank shot is discriminated using an earlier return of the sensor
cam 13 to the home position, and if it occurs, the stapling
operation is repeated. In FIG. 13, the motor is rotated forwardly
(F2), and when it returns to its home position (F3), the
discrimination is made as to whether or not the time required for
the start of the forward rotation of the motor to the home position
is within a predetermined duration T1. If so, it is deemed that the
blank shot occurs, and therefore, the sequence goes back to F2,
where the stapling operation is performed.
FIG. 14 shows another embodiment for detecting trouble in the
stapler. In this embodiment, as shown in FIG. 14, a disk is fixed
to a shaft of the motor gear 11 and has slits at regular
circumferential intervals. A photosensor 502 is constituted by a
light emitting element 502a and a receiving element 502b and serve
to detect passages of the slits by the rotation of the disk
synchronized with the motor gear 11.
FIG. 15 is a block diagram of this example. The control circuit 301
determines the rotational speed of the motor gear 11 on the basis
of the time intervals between the signals indicative of passage of
slits, transmitted from the photosensor 502.
FIG. 16 shows a change of the rotational speed of the motor gear 11
with time, calculated on the basis of the signal from the
photosensor 502 by the control circuit 301. In this Figure, "a"
indicates a waveform when the staple is dispensed, is penetrated
through the sheets and is bent without trouble; and "b" indicates a
waveform when the blank shot occurs (the staple is not dispensed
even if the stapler is operated). Upon the blank shot, there is no
load applied for penetrating through the sheet or for bending the
staple, and therefore, the reduction of the rotational speed during
the period indicated by t.sub.2. If malfunction or staple jam
occurs, an overload is generally produced with the result that the
rotational speed extremely decreases during the period t.sub.2 as
shown by a reference c, even to such an extent that the motor
stops.
In this embodiment, when the rotational speed .omega.p at the
maximum load is about a predetermined level .omega..sub.O, it is
deemed that the correct stapling operation is performed. When
.omega..sub.p <.omega..sub.O -C1 (C1: variation). there is a
possibility that the staple is jammed, that a malfunction occurs or
that something is wrong with the stapling mechanism. On the other
hand, when .omega..sub.p >.omega..sub.O +C2, it is discriminated
that the blank shot has occurred.
FIG. 17 is a flow chart illustrating the operation of this example.
At step S4 of FIG. 17, the rotational speed .omega. of the motor
gear 11 is monitored. When .omega..sub.p<.omega.O -C1, which
means that the load is extremely large, it is deemed that staple
jam or the like is discriminated at step S5. Therefore, the motor
10 is rotated reversely, at step S9. When, on the other hand,
.omega..sub.p >.omega..sub.O +C2, which means that the load is
extremely small, it is discriminated that the blank shot occurs, at
step S6. Therefore, the stapling operation is repeated. The flow
chart of this figure is the same as of FIG. 7 with the exception of
the above described steps.
In the embodiment of FIG. 14, the load is discriminated on the
basis of the rotation of speed of the stapling gear 11, but it may
be discriminated using a rotational speed of any drive transmitting
part between the motor 10 and the driver 105.
When the driving source or the driver transmission involve a linear
movement, as in a solenoid, the load is detected on the basis of
the linear movement.
Alternatively, the load may be detected on the basis of variation
in the acceleration, since increase of the load produces
deceleration or negative acceleration in the movement of the
stapler. Therefore, the negative acceleration is detected, and if
it is beyond a normal range, the staple jam or blank shot or the
like may be discriminated.
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.
* * * * *