Shunt for reversing the conveyance direction of a document

Information

  • Patent Grant
  • 6244591
  • Patent Number
    6,244,591
  • Date Filed
    Friday, September 24, 1999
    25 years ago
  • Date Issued
    Tuesday, June 12, 2001
    24 years ago
Abstract
A shunt is described for reversing the direction of conveyance of a document or the like. The document is accepted by a front-end roller and supplied to a reversing roller. As soon as the trailing rear edge of the document has left the front-end roller, the direction of rotation of the reversing roller is reversed and this guides the document, with the rear edge leading, to an output roller which is disposed offset in height relative to the front-end roller and outputs the document in the opposite direction.
Description




CROSS-REFERENCE TO RELATED APPLICATIONS




Not Applicable




STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT




Not Applicable




REFERENCE TO A “MICROFICHE APPENDIX”




Not Applicable




BACKGROUND OF THE INVENTION




1. Technical Field




The field of the present invention is transporting sheets in an office machine. More specifically, the invention relates to a shunt for reversing the conveyance direction of a document or the like.




2. Background Art




With office machines such as printers, copiers and the like, it is frequently desirable to reverse the conveyance direction of a document. The document is, for example, a paper sheet or the like provided with recordings. Reversing the document needs to be accomplished such that the document is transported first with its front edge leading, and is then further conveyed with its rear edge leading.




Others have addressed reversing the conveyance of a sheet of paper. For example, it is known from DE 32 17 115 A1 to accept the leading edge of an arriving document with a reversible roller pair whose direction of rotation can be reversed. In front of the reversible roller pair is disposed a pivotable guidance roller. When the document has been pulled in by the reversible roller pair such that the document's rear edge has reached the guidance roller, the direction of rotation of the reversible roller pair is reversed and the guidance roller is pivoted such that the document is steered by the guidance roller into the desired direction for further conveyance with the document's rear edge leading. This known shunt has the disadvantage that a succeeding next document can only be supplied to the reversing roller pair when the preceding document has been completely output by the reversing roller pair. Consequently the shunt hinders the conveyance of the documents and limits the continuity of document conveyance.




In another known example, DE 195 06 181 A1 shows a shunt where a sheet is supplied by front-end rollers to a reversible roller pair whose direction of rotation is reversible. The reversible roller pair accepts the sheet supplied by the front-end rollers and conveys it until the rear edge of the sheet is released by the front-end rollers and has been pulled over a wedge-form shunt element. The direction of rotation of the reversing roller pair is subsequently reversed such that the rear edge of the document is now leading and is transported past the shunt element to the output rollers. As soon as the output rollers have taken hold of the sheet and are conveying it in the output direction, the reversing roller pair is opened such that the next succeeding sheet can be guided by the front-end rollers into the open gap of the reversing roller pair. It is thereby possible to guide the particular succeeding next sheet into the reversing roller pair before the preceding sheet is completely pulled out of the reversing roller pair. The front-end roller and the output roller cooperates with a common pressure roller such that the drawing-in speed of the front-end roller and the output speed of the output rollers are, by necessity, equal. The output speed thereby limits the drawing-in speed of the front-end roller.




Thus, there exists a need for a shunt which makes possible a closer continuity sequence of the conveyed documents.




SUMMARY OF THE INVENTION




In a shunt for reversing the conveyance direction of a document, the document is completely drawn in by a front-end roller pair and are output again in the opposite direction via a separate output roller pair. After the front-end roller pair, the leading edge of the document is accepted by a reversing roller. After the document is released from the front-end roller pair, the direction of rotation of the reversing roller is reversed. The document is then transported to an output roller pair which continues to transport the document. A pressure roller, which can be pivoted toward the document, holds the document in engagement with the reversing roller. When the reversing roller has conveyed the document such that its rear edge, now leading, has been taken hold of by the output roller pair, the pressure roller can be pivoted away from the revering roller so that a succeeding document, which has already been taken hold of by the front-end roller pair, can be guided between the reversing roller. The pressure roller can thereby be pivoted away. While the output roller pair outputs the preceding document in the opposite direction, the front-end roller pair can already be drawing in the succeeding document.




Advantageously, successive documents can thus overlap preceding documents within the shunt. In such a manner a closer sequential continuity of document conveyance is possible. The output roller pair and the front-end roller pair are independent of one another so that, for example, the output roller pair can guide the document away at a higher velocity than that achieved by the front-end rollers. The shunt thereby does not introduce a delay to document conveyance.











BRIEF DESCRIPTION OF DRAWINGS




The above mentioned and other objects and features of this invention and the manner of attaining them will become apparent, and the invention itself will be best understood by reference to the following description of the embodiment of the invention in conjunction with the accompanying drawings, wherein:




FIG.


1


. is a schematic vertical section showing the shunt made in accordance with the present invention in the acceptance position.





FIG. 2

is a schematic of the shunt of

FIG. 1

showing the shunt in the reversing position, and





FIGS. 3-4

are schematic of the short of

FIG. 1

showing the overlapping of acceptance and output of two successive documents.











BEST MODE FOR CARRYING OUT THE INVENTION




Referring now to

FIG. 1

, there is shown a shunt made in accordance with the present invention. The shunt receives a sheet-form document


10


from an office machine, for example a printer, which the document


10


supplied to the shunt from the left as shown in FIG.


1


. In the document supply path is disposed a first sensor


12


. As indicated by the arrow


11


in

FIG. 1

, the arriving document


10


arrives at a front-end roller


14


. The front-end roller


14


is driving at the circumferential speed V


1


. A pressure roller


16


cooperates with the front-end roller


14


in order to bring the document


10


and the front-end rollers


14


into frictional engagement. Those skilled in the art will recognize that the front-end roller


14


can comprise a cylinder, extending over the width of the document, or several rollers disposed on a common shaft.




An output roller


18


, offset in height, is disposed below the front-end roller


14


and axis-parallel with it. The output roller


18


is drivable with the circumferential speed V


2


, and cooperates with a pressure roller


20


. The output roller


18


can also comprise a continuous cylinder or several discrete rollers disposed on a common shaft. Typically, the circumferential speed V


2


will be greater than the circumferential speed V


1


.




The pressure rollers


16


and


20


are each freely rotatable and supported on legs of a brace


17


. The pressure rollers


16


and


20


are held in contact on the front-end roller


14


and the output roller


18


by a spring


19


. The pressure roller


16


consequently rotates at speed V


1


while the pressure roller


20


rotates at speed V


2


.




A drivable reversing roller


22


is disposed axis-parallel with the front-end roller


14


and with the output roller


18


. More specifically the reversing roller


22


is positioned on the side facing away from the arriving side of the front rollers behind the front-end roller


14


and the output roller


18


and, spaced apart therefrom This reversing roller


22


can also comprise a continuous cylinder or several discrete rollers disposed on a common shaft. The reversing roller


22


can be reversed under control and is drivable in both directions of rotation. A pressure roller


24


cooperates with the reversing roller


22


which is supported freely rotatably on the free end of a roller lever


26


. The roller lever


26


is pivotably supported at


27


in such a way that the pressure roller


24


can be pivoted between a position shown in

FIG. 1

away from the reversing roller


22


and a position shown in

FIG. 2

resting on the reversing roller


22


.




Adjacent to the roller lever


26


is connected a pivot flap


28


which extends substantially over the width of the document


10


and extends generally from a pivot bearing


29


in the region of the front-end roller


14


to the pressure roller


24


.




Adjacent to the output roller


18


is a guidance flap


30


, which is articulated pivotably about an axle


32


. The free end of the guidance flap


30


extends beyond the reversing roller


22


and comprises cutouts


33


in which the reversing roller


22


can extend through. The guidance flap


30


is pivotable between an upper position as depicted in

FIG. 1 and a

lower position as depicted in FIG.


2


. In the upper position (

FIG. 1

) the plane of the guidance flap


30


is outside of the circumference of the reversing roller


22


. In the lower pivot position (

FIG. 2

) the plane of the guidance flap


30


intersects the reversing roller


22


such that the latter extends through the cutouts


33


of the guidance flap


30


. In such a manner, the reversing roller


22


projects with its circumference above the top side of the guidance flap


30


. The roller lever


26


is preferably coupled with the pivot flap


28


and the guidance flap


30


such that these are pivoted jointly between the positions shown in

FIGS. 1 and 2

.




The operation of the shunt will now be discussed. A document


10


arrives from a printer in the direction of the arrow


11


as shown in FIG.


1


. The arriving document


10


is detected at its front edge by the sensor


12


whereupon the driving of the front-end roller


14


is started. The front-end roller


14


is driven in the drawing-in direction i.e. in the drawing in the counterclockwise rotation. The pressure roller


24


is raised by means of the roller lever


26


from the reversing roller


22


and pivoted upward. The guidance flap


30


is also pivoted upward such that it is located above the outer circumference of reversing roller


22


. The front edge of the incoming document


10


is taken hold of between the front-end roller


14


and its pressure roller


16


. As the document


10


is drawn in, the document


10


actuates a second sensor


34


which is disposed in the region of the entry gap of the front-end roller


14


. A signal from the second sensor


34


initiates the driving of the output roller


18


, in the counterclockwise direction as shown in FIG.


3


.




As soon as the trailing rear edge of document


10


has passed the first sensor


12


, a signal from sensor


12


causes both the roller lever


26


(with the pressure roller


24


) and the guidance flap


30


to be lowered from the position depicted in

FIG. 1

into the position as shown in FIG.


2


. The driving of the reversing roller


22


is set such that the reversing roller


22


rotates in the clockwise direction and has the same circumferential speed V


1


as the front-end roller


14


. The rpm of the front-end roller


14


can simultaneously be increased and thus the conveyance of the document


10


can be accelerated. With the lowering of the pressure roller


24


the leading front edge of document


10


can be clamped between the pressure roller


24


and the reversing roller


22


, and together with the front-end roller


14


, can convey the document farther to the right, as shown in the figures.




As soon as the trailing rear edge of document


10


has passed the second sensor


34


and is thus released from the front-end roller


14


, the signal of sensor


34


causes the pivot flap


28


to be pivoted downward. In such a manner, the rear region of the document


10


is pushed by the pivot flap


28


downwardly onto the guidance flap


30


, as is shown in FIG.


2


. The signal from the second sensor


34


also reverses the direction of rotation of the reversing roller


22


so that the reversing roller


22


now rotates, in the representation of the drawing, in the counterclockwise direction and thereby conveys the document


10


to the left, as is shown in

FIG. 2

by the arrow


13


. The rear edge of document


10


arrives thereby at the output roller


18


and is taken hold of by this output roller


18


and its pressure roller


20


and conveyed further. The driving of the reversing roller


22


takes place at the same circumferential speed V


2


as the driving of output roller


18


.




Now roller lever


26


, the connected pivot flap


28


, and the guidance flap


30


are pivoted upwardly as is shown in FIG.


3


. Thereby the shunt is ready to accept the succeeding next document


10


′.




As is shown in

FIG. 3

the succeeding next document


10


′ can already be accepted and drawn in through the front-end roller


14


while the preceding document


10


is still being conveyed and output by the output roller


18


. Indeed, with the guidance flap


30


raised beyond the circumference of the reversing roller


22


, which is now driven again in the clockwise direction, does not hinder the drawing-off of document


10


by the output roller


18


. The succeeding next document


10


′ can thus be drawn into the reversing roller


22


overlapping the preceding document even though the preceding document


10


has not been output completely via the output roller


18


. Further, the document can be drawn with the higher speed V


2


from the reversing roller


22


, as is shown in FIG.


4


. Thereby a higher document sequential throughout can be attained. In such a manner the shunt does not delay the usual conveyance documents output from an office machine.




While particular embodiments of the present invention have been disclosed, it is to be understood that various different modifications are possible and are contemplated within the true spirit and scope of the appended claims. There is no intention, therefore, of limitations to the exact abstract or disclosure herein presented.



Claims
  • 1. A shunt for reversing the conveyance direction of a document, comprising:a front-end roller pair for accepting the incoming document at its front edge; an output roller pair disposed axis-parallel and offset with respect to the front-end roller pair, the output roller pair for outputting the document with its rear edge leading in the opposite direction; a reversing roller disposed axis-parallel on the side opposing the incoming side of the front-end roller pair and of the output roller pair; and a guidance flap for raising the document from a circumference of the reversing roller when the rear edge of document has been taken hold of by the output roller pair and the document is being conveyed by the output roller pair, wherein the reversing roller takes hold of the document conveyed by the front end roller pair and transports the document further until the rear edge of document has left the front-end roller pair and subsequently reverses direction of rotation of the reversing roller to transport the rear edge of document to the output roller pair.
  • 2. The shunt according to claim 1, wherein the reversing roller is associated with a pressure roller, the pressure roller being pivotable toward the reversing roller and away from the reversing roller, and wherein the pressure roller is pivoted against the reversing roller at least during the time interval before the rear edge of the document has left the front-end roller pair until the rear edge of document has been taken hold of by the output roller pair.
  • 3. The shunt according to claim 2 wherein the guidance flap pivots, and the pivot motion of the guidance flap is coupled with a pivot motion of the pressure roller.
  • 4. The shunt according to claim 1, further including a pivot plate for urging the rear edge of document toward entry to the output roller pair after the document leaves the front-end roller pair.
  • 5. The shunt according to claim 4 wherein the pivot plate pivots, and the pivot motion of the pivot plate is coupled with a pivot motion of a pressure roller.
  • 6. The shunt according to claim 1, wherein a circumferential speed of the output roller pair is greater than the circumferential speed of the front-end roller pair.
  • 7. A shunt for reversing the conveyance direction of a document, comprising:a front-end roller pair for accepting the incoming document at its front edge; an output roller pair disposed axis-parallel and offset with respect to the front-end roller pair, the output roller pair for outputting the document with its rear edge leading in the opposite direction; a reversing roller disposed axis-parallel on the side opposing the incoming side of the front-end roller pair and of the output roller pair; and a pivot plate for urging the rear edge of document toward entry to the output roller pair after the document leaves the front-end roller pair, wherein the reversing roller takes hold of the document conveyed by the front end roller pair and transports the document further until the rear edge of document has left the front-end roller pair and subsequently reverses direction of rotation of the reversing roller to transport the rear edge of document to the output roller pair, and wherein the pivot plate pivots, and the pivot motion of the pivot plate is coupled with a pivot motion of a pressure roller.
  • 8. The shunt according to claim 7, wherein the reversing roller is associated with the pressure roller, the pressure roller being pivotable toward the reversing roller and away from the reversing roller, and wherein the pressure roller is pivoted against the reversing roller at least during the time interval before the rear edge of the document has left the front-end roller pair until the rear edge of document has been taken hold of by the output roller pair.
  • 9. The shunt according to claim 7, further including a guidance flap for raising the document from a circumference of the reversing roller when the rear edge of document has been taken hold of by the output roller pair and the document is being conveyed by the output roller pair.
  • 10. The shunt according-to claim 9, wherein the guidance flap pivots, and the pivot motion of the guidance flap is coupled with a pivot motion of the pressure roller.
  • 11. The shunt according to claim 7, wherein a circumferential speed of the output roller pair is greater than the circumferential speed of the front-end roller pair.
Priority Claims (1)
Number Date Country Kind
198 44 230 Sep 1998 DE
US Referenced Citations (7)
Number Name Date Kind
3942785 Stange Mar 1976
4486012 Bock et al. Dec 1984
4699367 Russel Oct 1987
5449164 Quesnel et al. Sep 1995
5449166 Lohmann et al. Sep 1995
5629762 Mahoney et al. May 1997
5690325 Morimoto Nov 1997
Foreign Referenced Citations (3)
Number Date Country
011 85 994 Jan 1965 DE
32 17 115 A1 Nov 1983 DE
195 06 181 A1 Feb 1995 DE