Sheet post-processing apparatus

Information

  • Patent Grant
  • 6231039
  • Patent Number
    6,231,039
  • Date Filed
    Friday, September 17, 1999
    25 years ago
  • Date Issued
    Tuesday, May 15, 2001
    23 years ago
  • Inventors
  • Original Assignees
  • Examiners
    • Ellis; Christopher P.
    • Mackey; Patrick
    Agents
    • Oblon, Spivak, McClelland, Maier & Neustadt, P.C.
Abstract
A sheet post-processing apparatus comprises a conveyer for conveying the sheets discharged from the image forming system; a conveying device for conveying the sheets discharged from the image forming system; a pair of upper trays for accommodating the sheets conveyed by the conveying devices, and being horizontally moved in order to align the sheets accommodated therein and fall down the aligned sheets; a pair of upper tray driving devices for providing a driving force to the upper trays; a transmission unit for transmitting the driving force of the upper tray driving device to the upper trays; a lower tray for loading the sheets fallen from the upper trays; and a lower tray driving device for moving the lower tray in upper and lower directions in order to retain distance between the upper trays and the lower tray within a predetermined range. Thus, the sheet post-processing apparatus can accommodate variant size sheets by mechanism consisting of simple and cheap elements.
Description




BACKGROUND OF THE INVENTION




1. Field of the Invention




The present invention relates to a sheet post-processing apparautus adjacent to a sheet discharging section of an image forming system such as a copier, a printer, a facsimile and so on. More particularly, it relates to a sheet post-processing apparatus capable of performing post-process such as a stapling or a punching to sheets on which images are formed by the image forming system.




2. Description of Related Art




Recently, the image forming system is developed from analogue type into digital type. The digital image forming appartus can perform one or more function(s) of copy function, print function, facsimile function and selectively discharge the sheets on which images are formed.




That is, since the digital image forming system can store image data to be copied or printed, the image forming system can print the images on the sheets and discharge the sheets on which the images are formed, according to sequency which user wants. Therefore, a sheet post-processing apparatus of the analogue image forming system requires a plurality of accommodation trays for sorting and accommodating the sheets, but a sheet post-processing apparatus of the digital image forming system, without a plurality of accommodation trays, can sort and accommodate the sheets by only one accommodation tray for temporarily accommodating the sheets until sheets are completely discharged from the image forming system.




As an embodiment of the new sheet post-processing apparatus, when the digital image forming system copies a manuscript consisting of a plurality of sheets to make a plurality of duplicates, the image forming system repeatedly performs operation which prints and discharges the manuscript successively until all the sheets are accommodated into the accommodation tray. Thereafter, the sheet post-processing apparatus accommodates the sheets into a tray which has a stacker function. In this case, if necessary, the sheet post-processing apparatus can staples(or punches) the discharged sheets before accommodating the sheets into the stacker.




Further, the accommodation tray for temporarily accommodating the sheets has an aligning function to align the sheets accommodated therein and an offset function to accommodate bundles of sheets to be post-processed in zigzags.




The sheet post-processing apparatus of the digital image forming system is disclosed in U.S. Pat. No. 5,385,340 and U.S. Pat. No. 5,021,837, and the sheet post-processing apparatuses are briefly explained in the following, referring to

FIGS. 1 and 2

.




As shown in

FIG. 1

, the conventional sheet post-processing apparatus is adjacent to a discharging section


2


of the image forming system


1


and is provided with a copy sheets discharged from the discharging section


2


. The copy sheets transferred to the conventional sheet post-processing apparatus are discharged from a sheet oulet


9


by a conveyer


4


and is accommodated into an aligning tray


5


slantedly disposed. In this case, an end of each of the copy sheets is supported by a pusher


8


disposed at lower portion of the aligning tray


5


so that the copy sheets may be aligned. Further, in order to accurately align the copy sheets, the conventional sheet post-processing apparatus has a roller


7


for moving the copy sheets accommodated into the aligning tray


5


toward pusher


8


.




When the process as above-mentioned is repeated and the sheets are completely discharged from the image forming system, a solenoid


5




a


connected to the aligning tray


5


operates to align a side of each of the sheets accommodated into the aligning tray


5


. Then, the conventional sheet post-processing apparatus performs a post-process by a punch(not shown) or a stapler


10


to the aligned sheets. Thereafter, the pusher


8


supporting the end of each of the sheets is forwardly moved by a motor


8




a


so that the post-processed sheets are accommodated into an accommodation tray


6


.




Further, the conventional sheet post-processing apparatus has a motor


6




a


capable of vertically moving the accommodation tray


6


. The motor


6




a


moves the accommodation tray


6


to the position suitable for accommodation of the sheets. That is, when a bundle of sheets is accommodated into the accommodation tray


6


, the motor


6




a


moves the accommodation tray


6


downward by a predetermined distance so that upper end of the accommodation tray


6


is positioned in place capable of accommodating the next bundle of sheets.




Furthermore, the conventional sheet post-processing apparatus has a motor


6




b


for horizontally moving the accommodation tray


6


in order to offset the sheets. As shown in

FIG. 2

, when a bundle of sheets is completely accommodated into the accommodation tray


6


, the motor


6




b


moves the accommodation tray


6


horizontally. At this time, when the next bundle of sheets is accommodated into the accommodation tray


6


, the previous bundle of sheets and the next bundle of sheets are positioned in zigzags. Therefore, when a plurality of bundles of sheets are accommodated into the accommodation tray


6


, it may be prevented that staples imbeded into the bundles are stacked and a portion of the sheets accommodated into the accommodation tray is higher than the other portions.




However, since the conventional sheet post-processing apparatus aligns a side of each of the sheets accommodated into the aligning tray by the solenoid, there is a problem that sizes of the sheets used for the apparatus should be uniform.




Further, when a plurality of sheets are accommodated into the accommodation tray, since a large of load is applied to the motor for horizontally moving the accommodation tray, expensive motor capable of generating great driving force should be used for the apparatus in order to bear the load.




Furthermore, since the conventional apparatus has a plurality of elements for moving the sheets(that is, a pusher, a motor to operate the pusher and so on), the structure is complex.




SUMMARY OF THE INVENTION




It is, therefore, an object of the present invention to provide a sheet post-processing apparatus capable of accommodating variant size sheets by mechanism consisting of simple and cheap elements.




In order to accomplish the above object, the sheet post-processing apparatus, according to the present invention, comprises: a conveyer for conveying the sheets discharged from an image forming system; a conveying device for conveying the sheets discharged from the image forming system; a pair of upper trays for accommodating the sheets conveyed by the conveying devices, and being horizontally moved in order to align the sheets accommodated therein and fall down the aligned sheets; a pair of upper tray driving devices for providing a driving force to the upper trays; a transmission unit for transmitting the driving force of the upper tray driving device to the upper trays; a lower tray for loading the sheets fallen from the upper trays; and a lower tray driving device for moving the lower tray in upper and lower directions in order to retain distance between the upper trays and the lower tray within a predetermined range.




In this case, the transmission unit of the present invention comprises a base plate having a first and a second supporting bars, a plurality of erect portions formed on the each upper tray member and having a through hole for passing the supporting bar, a plurality of belts to be moved by the driving force provided from the motors, a plurality of abutments fixed to the upper tray members and the belts so that the upper tray members are moved together the belts.











BRIEF DESCRIPTION OF THE ATTACHED DRAWINGS




Other features in structure, operation and advantages of the present invention will become more apparent to those skilled in the art from the following descriptions when in conjunction with the accompanying drawings, in which :





FIG. 1

is a side view showing a structure of a sheet post-processing apparatus of the prior art;





FIG. 2

shows operation of an accommodation tray of the sheet post-processing apparatus of the prior art;





FIG. 3

is a side view showing a structure of a sheet post-processing apparatus according to the present invention;





FIG. 4

is a perspective view showing a disassembly of an upper tray driving portion of the sheet post-processing apparatus according to the present invention;





FIG. 5

is a perspective view showing a disassembly of an abutment of the sheet post-processing apparatus according to the present invention;





FIG. 6

is a cross-sectional view showing an assembly of the

FIG. 5

;





FIG. 7

is a perspective view showing a disassembly of another embodiment of an abutment according to the present invention;





FIG. 8

is a cross-sectional view showing an assembly of the

FIG. 7

;





FIG. 9

shows a state accommodating sheets in the sheet post-processing apparatus according to the present invention;





FIG. 10

illustrates a state aligning the sheets in the sheet post-processing apparatus according to the present invention;





FIG. 11

depicts a state stapling the sheets in the sheet post-processing apparatus according to the present invention;





FIG. 12

represents a state loading a bundle of sheets into a lower tray of the sheet post-processing apparatus according to the present invention; and





FIG. 13

shows a state loading the next bundle of sheets into the lower tray of the FIG.


12


.











DETAILED DESCRIPTIONS OF A PREFERRED EMBODIMENT




Hereinafter, the embodiment according to the present invention will be described in detail, referring to the accompanying

FIGS. 3

to


13


.





FIG. 3

is a side view showing a structure of a sheet post-processing apparatus according to the present invention,

FIG. 4

is a perspective view showing a disassembly of an upper tray driving portion of the sheet post-processing apparatus,

FIG. 5

is a perspective view showing a disassembly of an abutment of the sheet post-processing apparatus,

FIG. 6

is a cross-sectional view showing an assembly of the

FIG. 5

,

FIG. 7

is a perspective view showing a disassembly of another embodiment of an abutment the sheet post-processing apparatus, and

FIG. 8

is a cross-sectional view showing an assembly of the FIG.


7


.




In

FIGS. 3

to


13


, the reference numerals are as follows:


30


indicates sheet post-processing apparatus,


31


conveyer,


32


sheet outlet,


33


upper tray,


33




a


first erect portions,


33




b


second erect portion,


33




c


through hole,


34


lower tray,


35


upper motors,


36


lower motor,


37


transmission unit,


38


stapler,


39


discharged sheets,


39




a


a bundle of sheets,


40


base plate,


41


first supporting bar,


42


second supporting bar,


43


abutment,


43




a


body,


43




b


groove,


43




c


protrusion,


43




d


insert hole,


44


belt pulley,


45


belt,


46


sensor,


47


protrusion guide,


48


abutment guide,


51


first pipe,


52


second pipe,


53


hollow member,


55


spring.




As shown in

FIG. 3

, the sheet post-processing apparatus according to the present invention has a conveyer


31


adjacent to the discharging section on the image forming system, a sheet outlet


32


formed on an end of the conveyer


31


, a pair of upper trays


33


adjacent to the sheet outlet


32


, a lower tray


34


located under the upper trays


33


. Further, the sheet post-processing apparatus has a stapler


38


. The stapler


38


is disposed at position not to influence on conveyance of the sheets. The conveyer


31


conveys sheets comming out of the image forming system toward the sheet outlet


32


so that the sheets are discharged through the sheet outlet


32


and are positioned on the upper trays


33


. At this time, the stapler


38


performs a stapling operation to the sheets to be discharged from the sheet outlet


32


, thereby making a bundle of sheets


39




a.


Thereafter, the bundle of sheets falls from the upper trays


33


and is loaded into the lower tray


34


.




In this case, the sheet post-processing apparatus has upper motors


35


for moving the upper trays


33


horizontally (that is, in direction orthoganal to the conveyance direction of the sheets), a transmission unit


37


for transmitting driving force of the upper motors


35


to the upper trays


33


. The upper motors


35


can adjust movement distance and movement direction of the upper trays


33


to be horizontally moved. Therefore, when the bundle of sheets


39




a


is accommodated between the upper trays


33


, the upper motors


35


move the upper trays


33


so that the bundle of the sheets


39




a


can fall from the upper trays


33


.




Further, the sheet post-processing apparatus has a lower motor


36


for vertically moving the lower tray


34


, a sensor(not shown) for detecting uppermost end of the lower tray


34


and then providing operation signal to the lower motor


36


. The lower motor


36


moves the lower tray


34


downward by thickness of the bundle of sheets


39




a


when the bundle of sheets


39




a


is loaded into the lower tray


34


. In this case, if user removes the bundle of sheets


39




a


loaded into the lower tray


34


, the lower motor


36


moves the lower tray


34


upward by the removed thickness. Therefore, distance between the upper trays


33


and the lower tray


34


may be always retained within a predetermined range so that the bundle of sheets


39




a


falling from the upper trays


33


is stably loaded into the lower tray


34


.




The transmission unit


37


, as shown in

FIG. 4

, has a base plate


40


, a first and second supporting bars


41


and


42


disposed at both sides of the base plate


40


in parallel to movement direction of the upper trays


33


, a pair of belts


45


connected to each of the upper motors


35


. Each of the belts


45


is moved in parallel to the first supporting bar


41


by a plurality of pulleys


44


and is spaced out the first supporting bar


41


. In this case, the upper trays


33


are movably joined to the first and second supporting bars


41


and


42


.




Further, each of the upper trays


33


includes a pair of first erect portions


33




a


having a through hole


33




c


capable of passing the first supporting bar


41


therethrough, a second erect portion


33




b


having a hole capable of passing the second supporting bar


42


therethrough, two abutments


43


fixed between the two first erect portions


33




a


of each the upper trays


33


. Each of the abutments


43


has a body


43




a.


The body


43




a


includes a groove


43




b


for fixing the belt


45


, a protrusion


43




c


for indicating a position of the upper tray


33


, an insert hole


43




d


for passing the first supporting bar


41


. Therefore, when the belt


45


fixed to the groove


43




b


of the abutment


43


is moved by driving force of the upper motors


35


, the upper tray


33


fixing the abutment


43


is moved along the first supporting bar


41


.




Further, the transmission unit


37


has a pair of sensors


46


disposed at both ends of the first supporting bar


41


. The sensors


46


detect positions of the protrusion


43




c.


At this time, positions of the protrusions


43




c


detected by the senosrs


46


are reference points for determining operating time and direction of the upper trays


33


.




Preferably, the sheet post-processing apparatus may have a pair of protrusion guides


47


disposed at positions adjacent to the sensors


46


of the base plate


40


, and a pair of abutment guides


48


disposed at positions opposite to the protrusion guides


47


. Each of the protrusion guide


47


is contacted to lower end of the protrusion


43




c


to prevent that the protrusion


43




c


removes from the detection area of the sensor


46


or collides with the sensor


46


. Further, each of the abutment guide


48


is contacted to lower end of the abutment


43


to prevent that the protrusion


43




c


removes from the detection area of the sensor


46


.




The abutment


43


, as shown in

FIG. 5

, has first and second pipes


51


and


52


protruded from both sides of the body


43




a


and having a through hole connected to the insert hole


43




d.


External diameter of each the pipe has size capable of being inserted into the through hole


33




c


of the first erect portion


33




a


and internal diameter of each the pipe has size capable of inserting the first supporting bar


41


. Further, the sheet post-processing apparatus has a hollow member


53


to be fitted to the through hole


33




c


of the first erect portions


33




a


and an E-ring


54


for fixing position of the hollow member


53


. The hollow member


53


has an inner space capable of inserting the first supporting bar


41


.




When the abutment


43


is assembled with the first erect portions


33




a


of the upper tray


33


, as shown in

FIG. 6

, the second pipe


52


is inserted into the through hole


33




c


of one erect portion


33




a


so that the abutment


43


is supported by the erect portion, and the first pipe


51


is supported by the hollow member


53


fixed to the other erect portion


33




a.


In this case, mounting positions of the first and second pipes


51


and


52


may be exchanged with each other.




More preferably, as shown in

FIG. 7

, the sheet post-processing apparatus has a spring


55


disposed at peripheral portion of the first pipe


51


. In this case, when the abutment


43


is assembled with the first erect portions


33




a


of the upper tray


33


, as shown in

FIG. 8

, the first pipe


51


is inserted into the through hole


33




c


of one erect portion


33




a


so that the abutment


43


is supported by the erect portion, and the second pipe


51


is supported by the hollow member


53


fixed to the other erect portion


33




a.


At this time, both ends of the spring


55


are respectively supported by the first pipe


51


and the one erect portion


33




a


supporting the first pipe


51


. Further, mounting positions of the first and second pipes


51


and


52


may be exchanged with each other. In this case, the spring


55


absorbs shock happening by movement of the upper trays


33


for aligning the sheets or size difference among the sheets owing to difference of manufacturing process. Therefore, the sheet post-processing apparatus according to the present invention can stably align the sheets.




The operation state of the present invention structured as above-mentioned will be explained, referring to the

FIGS. 9

to


13


.





FIG. 9

shows a state accommodating sheets in the sheet post-processing apparatus,

FIG. 10

illustrates a state aligning the sheets in the sheet post-processing apparatus,

FIG. 11

depicts a state stapling the sheets in the sheet post-processing apparatus,

FIG. 12

represents a state loading a bundle of sheets into a lower tray of the sheet post-processing apparatus, and

FIG. 13

shows a state loading the next bundle of sheets into the lower tray of the FIG.


12


.




As shown in

FIG. 9

, the sheets comming out of the image forming system are discharged through the sheet outlet


32


by the conveyer


31


and are accommodated between the upper trays


33


. In this case, the upper trays


33


are spaced out each other by a distance capable of accommodating the discharged sheets


39


. That is, if data such as width size of the discharged sheets


39


is transmitted from the image forming system to the sheet post-processing apparatus via an interface, the upper motors


35


are controlled by a CPU(not shown) to move the upper trays


33


in place capable of accommodating the discharged sheets


39


.




In the accommodation state, if the sheets


39


are completely accommodated into the upper trays


33


, as shown in

FIG. 10

, the upper motors


35


are repeatedly driven in “A” and “B” directions so that the upper trays


33


reciprocate in “C” and “D” directions and align the sheets


39


accommodated therein. In this case, if sizes of the sheets are different from each other, a shock is happened while the upper trays


33


align the sheets


39


, but the shock is absorbed by the spring


55


disposed at the abutments


43


. Therefore, when the upper trays


33


align the sheets


39


, it may be prevented that the sheets are creased or the apparatus according to the present invention is damaged.




Further, when a post-process such as a stapling is required, as shown in

FIG. 11

, the upper motors


35


are simultaneously driven in “B” direction. In this case, the upper trays


33


are simultaneously moved in “D” direction so that the sheets


39


are positioned on a side of the stapler


38


. At this time, the stapler


38


staples the sheets


39


to make a bundle of sheets


39




a


. Thereafter, the upper trays


33


accommodating the bundle of sheets


39




a


are moved in center portion of the apparatus.




In the both states, for loading the sheets into the lower tray


34


, as shown in

FIG. 12

, the upper motors


35


are driven in opposite directions(that is, “A” and “B” directions) so that the upper trays


33


are moved in opposite directions. That is, the left upper motor is driven in “B” direction to move the left upper tray in “D” direction and the right upper motor is driven in “A” direction to move the right upper tray in “C” direction. Therefore, the distance between the two upper trays


33


is widen so that the sheets can fall down. At this time, the fallen sheets are loaded into the lower tray


34


.




Further, when the post-processed bundle of sheets is many, as shown in

FIG. 13

, the upper motors


35


are simultaneously driven in “A” (or, “B”) direction so that the next bundle of sheets


39




a′


accommodated the upper trays


33


is stepped aside from the bundle of sheets


39




a


previously loaded into the lower tray


34


by a predetermined distance. Thereafter, the next bundle of sheets


39




a′


is fallen down by the principle same as description of the FIG.


12


. In this case, since staples imbeded into the two bundles of sheets are stepped aside from each other, it may be prevented that a portion of the sheets stacked on the lower tray


34


is higher than the other portions by the stacked staples. Therefore, upper surface of the sheets stacked on the lower tray may be substantially flatted.




Furthermore, the lower tray


34


is moved in up or down by the lower motor


36


driving in positive or negative direction, thereby being spaced out the upper trays


33


so that the bundles of sheets may be stably accommodated.




In the sheet post-processing apparatus according to the present invention, since upper trays move in horizontal direction to make a space capable of accommodating the sheets, the present invention can accommodate variant size sheets.




Further, since the number of parts for organizing the apparatus of the present invention is reduced as compared with that of the prior art, the apparatus can be miniaturized.




Furthermore, since motor generating great driving force is unnecessary, manufacturing cost of the apparatus may be reduced.




It should be understood that the present invention is not limited to the particular embodiment disclosed herein as the best mode contemplated for carrying out the present invention and is not limited to the specific embodiment described in this specification except as defined in the appended claims.



Claims
  • 1. A sheet post-processing apparatus for post-processing sheets discharged from discharging section of an image forming system, comprising:a conveying device for conveying said sheets discharged from said image forming system; a pair of upper trays for accommodating said sheets conveyed by said conveying devices, and being horizontally moved in order to align said sheets accommodated therein and fall down said aligned sheets; a pair of upper tray driving devices for providing a driving force to said upper trays; a transmission unit for transmitting said driving force of said upper tray driving device to said upper trays; a lower tray for loading said sheets fallen from said upper trays; and a lower tray driving device for moving said lower tray in upper and lower directions in order to retain distance between said upper trays and said lower tray in a predetermined range.
  • 2. The apparatus as recited in claim 1, wherein each of said upper tray driving devices includes a motor for providing said driving force to each of said upper trays.
  • 3. The apparatus as recited in claim 2, wherein each of said motors adjusts movement distance and movement direction of said each upper tray to be horizontally moved.
  • 4. The apparatus as recited in claim 3, wherein said transmission unit includes a base plate having a first and a second supporting bars disposed thereon, a plurality of erect portions formed on said each upper tray and having a through hole for passing said supporting bar, a plurality of belts to be moved by said driving force provided from said motors, a plurality of abutments fixed to said upper trays and said belts so that said upper trays are moved together said belts.
  • 5. The apparatus as recited in claim 4, wherein said transmission unit further includes a protrusion formed on a side of each of said abutments, a plurality of sensors disposed at both sides of said first supporting bar and detecting position of said protrusion in order to detect positions of said abutments.
  • 6. The apparatus as recited in claim 5, wherein said transmission unit further includes a pair of protrusion guides disposed at both sides of said first supporting bar, a pair of abutment guides disposed at positions opposite to said protrusion guides, andsaid protrusion guides and said abutment guides prevent that said protrusions and said abutments remove from a detection area of said sensors.
  • 7. The apparatus as recited in claim 5, wherein each of said abutment includes a body having an insert hole for passing said first supporting bar, a pair of pipes elongated from both sides of said body, andwherein, said pipes have an external diameter capable of being inserted into said through hole of said erect portion and an internal diameter capable of passing said first supporting bar.
  • 8. The apparatus as recited in claim 7, wherein said transmission unit further includes a hollow member inserted into said through hole of one of said erect portions in order to support one of said pipes, a join member for fixing position of said hollow member inserted into said through hole.
  • 9. The apparatus as recited in claim 8, wherein said transmission unit further includes a spring surrounding peripheral portion of the other pipe without being supported by said hollow member.
Priority Claims (1)
Number Date Country Kind
98-38424 Sep 1998 KR
US Referenced Citations (10)
Number Name Date Kind
3410424 Rooney, Jr. Nov 1968
4473425 Baughman et al. Sep 1984
4611741 Wilson Sep 1986
5021837 Uto et al. Jun 1991
5285249 Mahoney Feb 1994
5385340 Hiroi et al. Jan 1995
5447298 Watanabe et al. Sep 1995
5803706 Achelphohl Sep 1998
5961274 Bors Oct 1999
6106219 Newsome et al. Aug 2000
Foreign Referenced Citations (2)
Number Date Country
403111372A May 1991 JP
8-9451 Jan 1996 JP