CA1178304A - Retard drive inverter - Google Patents
Retard drive inverterInfo
- Publication number
- CA1178304A CA1178304A CA000381861A CA381861A CA1178304A CA 1178304 A CA1178304 A CA 1178304A CA 000381861 A CA000381861 A CA 000381861A CA 381861 A CA381861 A CA 381861A CA 1178304 A CA1178304 A CA 1178304A
- Authority
- CA
- Canada
- Prior art keywords
- substrate
- sheet
- inverter
- channel
- drive
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Landscapes
- Separation, Sorting, Adjustment, Or Bending Of Sheets To Be Conveyed (AREA)
- Registering Or Overturning Sheets (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A copier capable of producing simplex and duplex copies includes a tri-roll inverter that employs a ball on roll return force applicator located downstream from the tri-roll input/output members. A sheet coming into the inverter is driven by a pair of the tri-rolls into a nip formed between the ball and roll of the return force applicator. The roll which has a minimal friction force is rotated continuously in the opposite direction to the incoming sheet. When the last portion of the sheet is driven into the ball on roll nip, the friction force of the nip will cause the sheet to buckle into an output nip of the tri-roll members for outward movement.
A copier capable of producing simplex and duplex copies includes a tri-roll inverter that employs a ball on roll return force applicator located downstream from the tri-roll input/output members. A sheet coming into the inverter is driven by a pair of the tri-rolls into a nip formed between the ball and roll of the return force applicator. The roll which has a minimal friction force is rotated continuously in the opposite direction to the incoming sheet. When the last portion of the sheet is driven into the ball on roll nip, the friction force of the nip will cause the sheet to buckle into an output nip of the tri-roll members for outward movement.
Description
RETARD DRIVE INVERTER
The present invention relates to an improved sheet inverting system, and more particularly to an inverter providing improved handling of 5 variable sized sheets within the inverter which employs a return force applicator.
As xerographic and other copiers increase in speed, and become more automatic, it is increasingly important to provide higher speed yet more reliable and more automatic handling of both the copy sheets being 10 made by the copier and the original document sheets being eopied. It is desired to accommodate sheets which may vary widely in size, weight, thickness, material, condition, humidity, age, ete. These variations change the beam strength or flexural resistance and other characteristics of the sheets. Yet the desire for automatic and high speed handling of such sheets 15 without jams, misfeeds, uneven feeding times9 or other interruptions increases the need for reliability of all sheet handling components. A sheet inverter is one such sheet handling component with particular reliability problems.
Although a sheet inverter is referred to in the copier art as an 20 "inverter", its function is not necessary to immediately turn the sheet over (i.e., exchange one face for the other). Its function is to effectively reverse the sheet orientation in its direction of motion. That is, to reverse the lead edge and trail edge orientation of the sheet. Typically in inverter devices, as disclosed here, the sheet is driven or fed by feed rollers or other suitable ~5 sheet driving mechanisms into a sheet reversing ehute. By then reversing the motion of the sheet within the chute and feeding it back out from the chute, the desired reversal of the leading and trailing edges of the sheet in the sheet path is accomplished. Depending on the location and orientation of the inverter in a particular sheet path, this may, or may not, also 30 accomplish the inversion (turning over) of the sheet. In some applications, for example, where the "inverter" is lo~ated at the corner of a 90 to 180 inherent bend in the copy sheet path, the inverter may be used to actually prevent inverting of a sheet at that point, i.e., to maintain the same side of the sheet face-up before and after this bend in the sheet path. On the other 35 hand, if the entering and departing path of the sheet, to and from the inverter, is in substantially the same plane, the sheet will be inverted by the , ~ :
.
.
~ 7~3 ,~
inverter. Thus, inverters have numerous applications in the handling of either original documents or copy sheets to either maintain, or change, the sheet orientationO
Inverters are particularly useful in various systems of pre or post collation copying, for inverting the original documentsl or for maintaining proper collation of the sheets. The facial orientation OL the copy sheet determines whether it may be stacked in forward or reversed serial order to maintain collationO
Generally, the inverter is associated with a by-pass sheet path and gate so that a sheet may selectively by-pass the inverter, to provide a choice of inversion or non-inversion. The present invention may be utilized, for example, in the chute inverter of a simplex/duplex copying system of the type disclosed in U.S. Patent 4,278,344, issued July 14, 1981, Ravi B.
Sahay.
Typically in a reversing chute type inverter, the sheet is fed in and then wholly or partially released from a positive feeding grip or nip into the inverter chute, and then reacquired by a different feeding nip to exit the inverter chute. Such a temporary loss of positive gripping of the sheet by any feed mechanism during the inversion increases the reliability problems of such inverters.
The present invention is directed to improving the reliability of the inverter in this and other critical aspects of this operation, yet to also accommodate a range of different sheet sizes within the same size inverter and the same mechanismO The present invention provides these improvements with an extremely low cost and simple inverter apparatus having a uniquely constructed and positioned constantly rotating ball on roll retard drive mechanism located downstream of the sheet input and output drives.
As noted above, many inverters, particularly those utilizing only gravity, have reliability problems in the positive output or return of the sheet at a "
"
.
. ' 3~
- 2a -consistent time after the sheet is released in the inverter chute. Those inverters which use chute drive rollers or other drive mechanisms have a more positive return movement of the sheet, but this normally requires a movement actuator (clutch or solenoid) for the drive and either a sensor or a timing mechanism to determine the proper time to initiate the actuation of this drive mechanism so that it does not interfere with the input .
, ~ ~t783Q.~
3 t~
movement of the sheet, and only thereafter acts on the sheet to return it to the exit nip or other feed-out means. Furthermore, inverter reliability problems are aggravated by variations in the condition or size of the sheet.
For example, a pre-set curl in the sheet can cause the sheet to assume an undesirable configuration wit~in the chute when it is released thérein, and interf ere with f eed-out.
In contrast~ the inverter disclosed herein can provide positive buckling of the sheet between drive rollers located within a chute engaging the lead edge of the sheet and an input feeder which is pushing the trail edge lO of the sheet into the chute, for a positive sheet ejection force. Yet a conventional range of sheet dimensions, and 8 wide range of sheet thic~-nesses and weights, may be accom modated within this inverter chute, without sacrificing reliability of output feeding from the inverter chute.
The inverter disclosed herein allows a highly accurate and compact inverter 15 configuration.
A preferred feature of the present invention is to provide in a sheet inverter mechanism with sheet feed means for feeding a sheet into and out of a first end of a sheet reversing chute, to reverse the lead and trail edge orientation of the sheet, the improvement comprising nip means 20 located within the chute for applying a constant force to the sheet that is opposite to the initial sheet direction as the sheet is being driven toward the nip means.
A further preferred feature is to provide, in a method of re-versing the direction of sheets of variable dimensions by feeding them into 25 one end of a sheet reversing chute and feeding them out of the same end of said chute so that the lead edge and trail edge orientation of the sheets is reversed, the improvement comprising driving the lead edge of the sheets into said chute, and applying a return for~e against the sheets as they are driven into said chute, said return forcs being applied by a ball on roll nip 30 with said ba11 on roll constantly rotating in a direction opposite to the incoming direction of the sheets in order to bucl<le and thereby positively urge the trail edge of the sheets back out from the chute.
3a!4 -3a-Various aspects of the invention are as follows:
A substrate inverter, comprising: (a) inversion channel means; (b) input drive means having two drive rollers for driving a substrate into said channel means; (c) output drive means having two drive rollers, one of which is shared with said input drive means for driving a substrate out of said channel means; and (d) nip means for resisting substrate movement into said channel means located downstream of said input drive means a distance less than the length of said -substrate so that a continuous drive force is applied to the substrate in a direction opposite to the initial incoming sheet direction after the substrate is driven into said nip means b~ said input means, said force maintaining said sub-strate in contact with said shared drive roller as the last portion of the substrate ~eaves said input means so that the force of said nip means wiil drive the substrate to said output means for movement out of said channel means.
A method for inverting a substrate comprising the steps of: driving a substrate into a channel with an input force, resisting the driving of said substrate into said channel with a continuous force less than said input force but large enough to move said substrate along said channel in the absence of said input force, and grasping said sheet and pulling it from said channel as said continuous force moves said sheet to an output position once the driving step has been completed.
Further features and advantages of the invention pertain to the particular apparatus and steps whereby the above noted aspects of the invention are attained. Accord-ingly, the invention will be better understood by referenceto the following description, and to the drawings forming a part 7: `
,:
' .
~7~3~
- 4 ~
thereof, which are approximately to scale, wherein:
Figure 1 is a schematic side view of an exemplary copier incorporating an aspect of the present invention.
Figure 2 is an exploded side view of the inverter shown in Figure 1.
Figure 3 is a partial side view of another embodiment of the invention in a vertical plane.
Figure 4 is a partial side view of yet another embodiment of the invention in a vertical plane.
Figure 5 is an embodiment of the invention as shown in Figure 1 with a buckle inhibitor added.
Referring to the exemplary xerographic copier 10 shown in Figure 1, and its exemplary automatic document feeding unit 20, it will be appreciated that various other recirculating document feeding units and copiers may be utilized with the present invention. This copier is described in detail in aforementioned U.S.
Patent 4,278,344.
The exemplary copier 10 conventionally includes a xerographic photoreceptor belt 12 and the xerographic stations acting thereon for respectively charging 13, exposing 14, developing 15, driving 16 and cleaning 17.
The copier 10 is adapted to provide duplex or simplex pre-collated copy sets from either duplex or simplex original documents copied from the recirculating document handler 20. Two separate copy sheet trays 106 and 107 are provided to feed clean copy sheets from either one. The control of the sheet feeding is, conventionally, by the machine controller 100. The controller 100 is preferably a known programmable microprocessor as exemplified by U.S. Patent 4,144,450, issued to J. Donahue et al. on March 13, 1979, which conventionally also controls all of the other machine functions described herein including the operation of the document feeder, the document and copy sheet gates, the feeder drives, etc. As further disclosed, it also conventionally provides for storage and comparison of the counts of the copy sheets, the number of documents 3~
- 4a -recirculated in a document set, the number of copy sets selected by the operator through the switches thereon, etc.
The copy sheets are fed from a selected one of the trays 106 or -. . .
-~, ~, ',, ' '' :
, . ~ '' .
-~L~t~3~
lD7 to the xerographic transfer station 112 for the transfer of the xerographic image of a doucment page to one side thereof. The copy sheets here are then fed through vacuum transports vertically up through a conventional roll fuser 114 for the fusing of the toner image thereon. From the fuser, the COW
5 sheets are fed to a gate 118 which functions as an inverter selector ~inger.
Depending on the position of the gate 118, the copy sheets will either be deflected into a sheet inverter 116 or bypass the inverter and be fed directly onto a second decision gate 120. Those copy sheets which bypass $he inverter 116 (the normal path here) have a 90~ path deflection before 10 reaching the gate 120 which inverts the copy sheets into a face-up orientation, i.e., the image side which has just been transferred and fused is face-up at this point. The second decision gate 120 then either deflects the sheets without inversion directly into an output tray 122 or deflects the sheets into a transport path which carries them on without inversion to a third decision gate 124. This third gate 124 either passes the sheets directly on without inversion into the output path 128 of the copier, or deflects the sheets into a duplex inverting roller transport 126. The inverting transport 126 feeds the copy sheets into a duplex tray 108. The duplex tray 108 provides intermediate or buffer storage for those COW sheets which have been printed on one side and on which it is desired to subsequently print an image on the opposite side thereof, i.e., the sheets being duplexed. Due to the sheet inverting by the roller 126, these buffer set copy sheets are stacked into the duplex tray fac~down. They are stacked in the duplex tray 108 on top of one another in the order in which they were copied.
For the completion of duplex copying9 the previously simplexed copy sheets in the tray 108 are fed seriatim by the bottom feeder 109 from the duplex tray back to the transfer station for the imaging of their second or opposite side page image. This duplex copy sheet pa$h is basically the same copy sheet path provided for the clean sheets from the trays 106 or 107, illustrated at the right hand and bottom of Pigure 1. It may be seen that this sheet feed path between the duplex feeder 109 and the transfer station 112 inverts the copy sheets once. However, due to the inverting roller 126 ha~ring previously stacked these sheets face-down in the tray 10~, they are presented to the transfer station 112 in the proper orientation, i.e., with their blank or opposite sides facing the photoreceptor 12 to receive the second side image. The now duplexed copy sheets are then fed out through the . :
same output path through the fuser 114 past the inverter 116 to be st~cked with the second printed side faceup. These completed duplex copy sheets may then be stacked in the output tray 122 or fed out past the gate 124 into the output path 128.
The output path 128 transports the finished copy sheets (simplex or duple2~) either to another output tray, or, preferably, to a finishing station where the completed pre-collated copy sheets may be separated and finished by on-line stapling, stitching, glueing, binding, and/or off-set stacking.
In reference to an aspect of the present invention and l~igure 2, when inversion of copy sheets is required, for example, job recovery, maintaining face-up or face-down output collation, simplex/duplex cowing with an odd number of simplex copies, etc., tri-roll inverter 116 is used.
Copy sheets are fed from either tray 106 or 107 past transfer means 112 and onto conveyor 115. As a sheet leaves conveyor 11~, it approaches decision gate 118 which is controlled by controller 100. Gate 118 is actuated to the right as viewed in Figure 1 which causes sheet 80 to be deflected into an input nip fc>rmed by rollers 70 and 72. These rollers drive the sheet into chute 73 and subsequently into a second ball on roll nip formed between idler ball 76 and drive roller 77 which is driven by conventional means (not shown). Drive roller 77 is constantly rotating in a clockwise direction which is opposite to input drive roller 72. The nip formed between ball 76 and roller 77 has slight frictional characteristics and, therefore, apply a con-tinuous retard force against the incoming sheet. However, this retarding force is not enough to inhibit forward movement of tne incoming sheet through the nip. When the last portion OI the sheet 80 leaves the nip be-tween rollers 70 and 72, the friction force of nip 76, 77 will cause the sheet to buckle around roller 70 and into the output nip formed by rollers 70 and 71 for outward movement. As soon as the sheet is "walked" around roller 70 to the exit nip and is under control of the output rollers, the ne~t sheet can be fed into the inverter allowing simultaneous sheet inversion. After moving through nip 70, 71, the sheet approaches gate 120 which is actuated by controller 100 into either the dotted line or solid line positions shown in Figure 1 depending on the reason for inverting.
Alternative embodiments of the present invention especially adapted for employing the friction retard applicator in a vertical plane are shown in Figure 3 and 4. In all of the embodiments that follow, like . .
8~4 numerals represent like parts described in respect to ~igures 1 and 2. In reference to ~igure 3, a sheet to be inverted is forwarded down through channel 73 and through the friction retard applicator nip formed between drive roller 77 and idler roller 76. Continuously rotating roller 77 applies a retard force against the incoming sheet and after the sheet escapes the drive force of the members that forwarded it into the channel 73, the frictional force of rotating roller 77 will drive the sheet back in the di-rection from which it came. ~dler roller 76 is supported adjacent to drive roller 77 by housing 74 which has an angled tunnel therein within which roller 76 rides. The tunnel is shaped such that idler roller 76 lightly touches drive roller 77 and forms a nip therewith. ~2f~
7~ In Figure 4, sheet 80 is pressed against drive roller 77 bylidler roller ~ The idler roller is spring loaded at 79 with the spring pressure being transmitted through arm 75 and shaft 85. In operation, roller 77 has a small friction force and is rotated in the opposite direction to the incoming sheet 80 continuously. When the last portion of the sheet leaves the driving nip which forces it into channel 73, the friction force of the nip formed between drive roller 77 and idler roller 76 will cause the sheet to buckle into a nip located upstream thereof for outward movement. The use of a ball on roll system in either a horizontal or vertical plane allows a side registration to be achieved within the inverter channel.
In the case of horizontal positioning of the inverter, it has been found that successful inversion of sheets ranging from basic weights of 13#
to 32# can be accommodated with a retard applicator nip force equal to~
.005 lbs. However, one of the limits to successful inversion of ligher weights of paper concurrent with maintaining a large enough drive force for heavier weights of paper is the buckling which occurs with the lighter weights of sheets. Instead of the sheets being forced through the output nip, they buckle. An answer to this problem is shown in Figure 5 which is identical to Figure 1 with the addition of buckle inhibitor 88. This device could take the form of pivoting ski 89 as shown or the ski could be spring loaded against the bottom of inverter channel 73. Incoming sheets are forced under the ski, thus not allowing the sheet to buckle.
In conclusion, a substrate inverter is disclosed that includes an input nip formed by rollers 70 and 72. Roller 72 drives the substrate rnaterial ~0 through a retard drive force applicator having a nip formed . , ~ .
~L7~33~4 between ball 76 on roller 77. The roller is rotating in a direction to oppose the motion of the incoming substrate with a small friction force. However, this fric~ion force is small enough so as to allow the incoming substrate to be forced through the nip. After the last portion of the substrate passes 5 through the input nip, the friction force from the ball on roll nip forces thetrail edge of the incoming sheet to maintain contact with roller 70. This causes the trail edge to "walk around" to the exit nip formed between rollers 70 and 71. As soon as the substrate is under control of the exit nip, the next substrate can be fed into the inverter allowing simultaneous substrate 10 inversion.
While the inverter system disclosed herein is preferred, it will be appreciated that various alternatives, modifications, variations or improv~
ments thereon may be made by those skilled in the art, and the following claims are intended to encompass all of those falling within the true spirit 15 and scope of the invention.
The present invention relates to an improved sheet inverting system, and more particularly to an inverter providing improved handling of 5 variable sized sheets within the inverter which employs a return force applicator.
As xerographic and other copiers increase in speed, and become more automatic, it is increasingly important to provide higher speed yet more reliable and more automatic handling of both the copy sheets being 10 made by the copier and the original document sheets being eopied. It is desired to accommodate sheets which may vary widely in size, weight, thickness, material, condition, humidity, age, ete. These variations change the beam strength or flexural resistance and other characteristics of the sheets. Yet the desire for automatic and high speed handling of such sheets 15 without jams, misfeeds, uneven feeding times9 or other interruptions increases the need for reliability of all sheet handling components. A sheet inverter is one such sheet handling component with particular reliability problems.
Although a sheet inverter is referred to in the copier art as an 20 "inverter", its function is not necessary to immediately turn the sheet over (i.e., exchange one face for the other). Its function is to effectively reverse the sheet orientation in its direction of motion. That is, to reverse the lead edge and trail edge orientation of the sheet. Typically in inverter devices, as disclosed here, the sheet is driven or fed by feed rollers or other suitable ~5 sheet driving mechanisms into a sheet reversing ehute. By then reversing the motion of the sheet within the chute and feeding it back out from the chute, the desired reversal of the leading and trailing edges of the sheet in the sheet path is accomplished. Depending on the location and orientation of the inverter in a particular sheet path, this may, or may not, also 30 accomplish the inversion (turning over) of the sheet. In some applications, for example, where the "inverter" is lo~ated at the corner of a 90 to 180 inherent bend in the copy sheet path, the inverter may be used to actually prevent inverting of a sheet at that point, i.e., to maintain the same side of the sheet face-up before and after this bend in the sheet path. On the other 35 hand, if the entering and departing path of the sheet, to and from the inverter, is in substantially the same plane, the sheet will be inverted by the , ~ :
.
.
~ 7~3 ,~
inverter. Thus, inverters have numerous applications in the handling of either original documents or copy sheets to either maintain, or change, the sheet orientationO
Inverters are particularly useful in various systems of pre or post collation copying, for inverting the original documentsl or for maintaining proper collation of the sheets. The facial orientation OL the copy sheet determines whether it may be stacked in forward or reversed serial order to maintain collationO
Generally, the inverter is associated with a by-pass sheet path and gate so that a sheet may selectively by-pass the inverter, to provide a choice of inversion or non-inversion. The present invention may be utilized, for example, in the chute inverter of a simplex/duplex copying system of the type disclosed in U.S. Patent 4,278,344, issued July 14, 1981, Ravi B.
Sahay.
Typically in a reversing chute type inverter, the sheet is fed in and then wholly or partially released from a positive feeding grip or nip into the inverter chute, and then reacquired by a different feeding nip to exit the inverter chute. Such a temporary loss of positive gripping of the sheet by any feed mechanism during the inversion increases the reliability problems of such inverters.
The present invention is directed to improving the reliability of the inverter in this and other critical aspects of this operation, yet to also accommodate a range of different sheet sizes within the same size inverter and the same mechanismO The present invention provides these improvements with an extremely low cost and simple inverter apparatus having a uniquely constructed and positioned constantly rotating ball on roll retard drive mechanism located downstream of the sheet input and output drives.
As noted above, many inverters, particularly those utilizing only gravity, have reliability problems in the positive output or return of the sheet at a "
"
.
. ' 3~
- 2a -consistent time after the sheet is released in the inverter chute. Those inverters which use chute drive rollers or other drive mechanisms have a more positive return movement of the sheet, but this normally requires a movement actuator (clutch or solenoid) for the drive and either a sensor or a timing mechanism to determine the proper time to initiate the actuation of this drive mechanism so that it does not interfere with the input .
, ~ ~t783Q.~
3 t~
movement of the sheet, and only thereafter acts on the sheet to return it to the exit nip or other feed-out means. Furthermore, inverter reliability problems are aggravated by variations in the condition or size of the sheet.
For example, a pre-set curl in the sheet can cause the sheet to assume an undesirable configuration wit~in the chute when it is released thérein, and interf ere with f eed-out.
In contrast~ the inverter disclosed herein can provide positive buckling of the sheet between drive rollers located within a chute engaging the lead edge of the sheet and an input feeder which is pushing the trail edge lO of the sheet into the chute, for a positive sheet ejection force. Yet a conventional range of sheet dimensions, and 8 wide range of sheet thic~-nesses and weights, may be accom modated within this inverter chute, without sacrificing reliability of output feeding from the inverter chute.
The inverter disclosed herein allows a highly accurate and compact inverter 15 configuration.
A preferred feature of the present invention is to provide in a sheet inverter mechanism with sheet feed means for feeding a sheet into and out of a first end of a sheet reversing chute, to reverse the lead and trail edge orientation of the sheet, the improvement comprising nip means 20 located within the chute for applying a constant force to the sheet that is opposite to the initial sheet direction as the sheet is being driven toward the nip means.
A further preferred feature is to provide, in a method of re-versing the direction of sheets of variable dimensions by feeding them into 25 one end of a sheet reversing chute and feeding them out of the same end of said chute so that the lead edge and trail edge orientation of the sheets is reversed, the improvement comprising driving the lead edge of the sheets into said chute, and applying a return for~e against the sheets as they are driven into said chute, said return forcs being applied by a ball on roll nip 30 with said ba11 on roll constantly rotating in a direction opposite to the incoming direction of the sheets in order to bucl<le and thereby positively urge the trail edge of the sheets back out from the chute.
3a!4 -3a-Various aspects of the invention are as follows:
A substrate inverter, comprising: (a) inversion channel means; (b) input drive means having two drive rollers for driving a substrate into said channel means; (c) output drive means having two drive rollers, one of which is shared with said input drive means for driving a substrate out of said channel means; and (d) nip means for resisting substrate movement into said channel means located downstream of said input drive means a distance less than the length of said -substrate so that a continuous drive force is applied to the substrate in a direction opposite to the initial incoming sheet direction after the substrate is driven into said nip means b~ said input means, said force maintaining said sub-strate in contact with said shared drive roller as the last portion of the substrate ~eaves said input means so that the force of said nip means wiil drive the substrate to said output means for movement out of said channel means.
A method for inverting a substrate comprising the steps of: driving a substrate into a channel with an input force, resisting the driving of said substrate into said channel with a continuous force less than said input force but large enough to move said substrate along said channel in the absence of said input force, and grasping said sheet and pulling it from said channel as said continuous force moves said sheet to an output position once the driving step has been completed.
Further features and advantages of the invention pertain to the particular apparatus and steps whereby the above noted aspects of the invention are attained. Accord-ingly, the invention will be better understood by referenceto the following description, and to the drawings forming a part 7: `
,:
' .
~7~3~
- 4 ~
thereof, which are approximately to scale, wherein:
Figure 1 is a schematic side view of an exemplary copier incorporating an aspect of the present invention.
Figure 2 is an exploded side view of the inverter shown in Figure 1.
Figure 3 is a partial side view of another embodiment of the invention in a vertical plane.
Figure 4 is a partial side view of yet another embodiment of the invention in a vertical plane.
Figure 5 is an embodiment of the invention as shown in Figure 1 with a buckle inhibitor added.
Referring to the exemplary xerographic copier 10 shown in Figure 1, and its exemplary automatic document feeding unit 20, it will be appreciated that various other recirculating document feeding units and copiers may be utilized with the present invention. This copier is described in detail in aforementioned U.S.
Patent 4,278,344.
The exemplary copier 10 conventionally includes a xerographic photoreceptor belt 12 and the xerographic stations acting thereon for respectively charging 13, exposing 14, developing 15, driving 16 and cleaning 17.
The copier 10 is adapted to provide duplex or simplex pre-collated copy sets from either duplex or simplex original documents copied from the recirculating document handler 20. Two separate copy sheet trays 106 and 107 are provided to feed clean copy sheets from either one. The control of the sheet feeding is, conventionally, by the machine controller 100. The controller 100 is preferably a known programmable microprocessor as exemplified by U.S. Patent 4,144,450, issued to J. Donahue et al. on March 13, 1979, which conventionally also controls all of the other machine functions described herein including the operation of the document feeder, the document and copy sheet gates, the feeder drives, etc. As further disclosed, it also conventionally provides for storage and comparison of the counts of the copy sheets, the number of documents 3~
- 4a -recirculated in a document set, the number of copy sets selected by the operator through the switches thereon, etc.
The copy sheets are fed from a selected one of the trays 106 or -. . .
-~, ~, ',, ' '' :
, . ~ '' .
-~L~t~3~
lD7 to the xerographic transfer station 112 for the transfer of the xerographic image of a doucment page to one side thereof. The copy sheets here are then fed through vacuum transports vertically up through a conventional roll fuser 114 for the fusing of the toner image thereon. From the fuser, the COW
5 sheets are fed to a gate 118 which functions as an inverter selector ~inger.
Depending on the position of the gate 118, the copy sheets will either be deflected into a sheet inverter 116 or bypass the inverter and be fed directly onto a second decision gate 120. Those copy sheets which bypass $he inverter 116 (the normal path here) have a 90~ path deflection before 10 reaching the gate 120 which inverts the copy sheets into a face-up orientation, i.e., the image side which has just been transferred and fused is face-up at this point. The second decision gate 120 then either deflects the sheets without inversion directly into an output tray 122 or deflects the sheets into a transport path which carries them on without inversion to a third decision gate 124. This third gate 124 either passes the sheets directly on without inversion into the output path 128 of the copier, or deflects the sheets into a duplex inverting roller transport 126. The inverting transport 126 feeds the copy sheets into a duplex tray 108. The duplex tray 108 provides intermediate or buffer storage for those COW sheets which have been printed on one side and on which it is desired to subsequently print an image on the opposite side thereof, i.e., the sheets being duplexed. Due to the sheet inverting by the roller 126, these buffer set copy sheets are stacked into the duplex tray fac~down. They are stacked in the duplex tray 108 on top of one another in the order in which they were copied.
For the completion of duplex copying9 the previously simplexed copy sheets in the tray 108 are fed seriatim by the bottom feeder 109 from the duplex tray back to the transfer station for the imaging of their second or opposite side page image. This duplex copy sheet pa$h is basically the same copy sheet path provided for the clean sheets from the trays 106 or 107, illustrated at the right hand and bottom of Pigure 1. It may be seen that this sheet feed path between the duplex feeder 109 and the transfer station 112 inverts the copy sheets once. However, due to the inverting roller 126 ha~ring previously stacked these sheets face-down in the tray 10~, they are presented to the transfer station 112 in the proper orientation, i.e., with their blank or opposite sides facing the photoreceptor 12 to receive the second side image. The now duplexed copy sheets are then fed out through the . :
same output path through the fuser 114 past the inverter 116 to be st~cked with the second printed side faceup. These completed duplex copy sheets may then be stacked in the output tray 122 or fed out past the gate 124 into the output path 128.
The output path 128 transports the finished copy sheets (simplex or duple2~) either to another output tray, or, preferably, to a finishing station where the completed pre-collated copy sheets may be separated and finished by on-line stapling, stitching, glueing, binding, and/or off-set stacking.
In reference to an aspect of the present invention and l~igure 2, when inversion of copy sheets is required, for example, job recovery, maintaining face-up or face-down output collation, simplex/duplex cowing with an odd number of simplex copies, etc., tri-roll inverter 116 is used.
Copy sheets are fed from either tray 106 or 107 past transfer means 112 and onto conveyor 115. As a sheet leaves conveyor 11~, it approaches decision gate 118 which is controlled by controller 100. Gate 118 is actuated to the right as viewed in Figure 1 which causes sheet 80 to be deflected into an input nip fc>rmed by rollers 70 and 72. These rollers drive the sheet into chute 73 and subsequently into a second ball on roll nip formed between idler ball 76 and drive roller 77 which is driven by conventional means (not shown). Drive roller 77 is constantly rotating in a clockwise direction which is opposite to input drive roller 72. The nip formed between ball 76 and roller 77 has slight frictional characteristics and, therefore, apply a con-tinuous retard force against the incoming sheet. However, this retarding force is not enough to inhibit forward movement of tne incoming sheet through the nip. When the last portion OI the sheet 80 leaves the nip be-tween rollers 70 and 72, the friction force of nip 76, 77 will cause the sheet to buckle around roller 70 and into the output nip formed by rollers 70 and 71 for outward movement. As soon as the sheet is "walked" around roller 70 to the exit nip and is under control of the output rollers, the ne~t sheet can be fed into the inverter allowing simultaneous sheet inversion. After moving through nip 70, 71, the sheet approaches gate 120 which is actuated by controller 100 into either the dotted line or solid line positions shown in Figure 1 depending on the reason for inverting.
Alternative embodiments of the present invention especially adapted for employing the friction retard applicator in a vertical plane are shown in Figure 3 and 4. In all of the embodiments that follow, like . .
8~4 numerals represent like parts described in respect to ~igures 1 and 2. In reference to ~igure 3, a sheet to be inverted is forwarded down through channel 73 and through the friction retard applicator nip formed between drive roller 77 and idler roller 76. Continuously rotating roller 77 applies a retard force against the incoming sheet and after the sheet escapes the drive force of the members that forwarded it into the channel 73, the frictional force of rotating roller 77 will drive the sheet back in the di-rection from which it came. ~dler roller 76 is supported adjacent to drive roller 77 by housing 74 which has an angled tunnel therein within which roller 76 rides. The tunnel is shaped such that idler roller 76 lightly touches drive roller 77 and forms a nip therewith. ~2f~
7~ In Figure 4, sheet 80 is pressed against drive roller 77 bylidler roller ~ The idler roller is spring loaded at 79 with the spring pressure being transmitted through arm 75 and shaft 85. In operation, roller 77 has a small friction force and is rotated in the opposite direction to the incoming sheet 80 continuously. When the last portion of the sheet leaves the driving nip which forces it into channel 73, the friction force of the nip formed between drive roller 77 and idler roller 76 will cause the sheet to buckle into a nip located upstream thereof for outward movement. The use of a ball on roll system in either a horizontal or vertical plane allows a side registration to be achieved within the inverter channel.
In the case of horizontal positioning of the inverter, it has been found that successful inversion of sheets ranging from basic weights of 13#
to 32# can be accommodated with a retard applicator nip force equal to~
.005 lbs. However, one of the limits to successful inversion of ligher weights of paper concurrent with maintaining a large enough drive force for heavier weights of paper is the buckling which occurs with the lighter weights of sheets. Instead of the sheets being forced through the output nip, they buckle. An answer to this problem is shown in Figure 5 which is identical to Figure 1 with the addition of buckle inhibitor 88. This device could take the form of pivoting ski 89 as shown or the ski could be spring loaded against the bottom of inverter channel 73. Incoming sheets are forced under the ski, thus not allowing the sheet to buckle.
In conclusion, a substrate inverter is disclosed that includes an input nip formed by rollers 70 and 72. Roller 72 drives the substrate rnaterial ~0 through a retard drive force applicator having a nip formed . , ~ .
~L7~33~4 between ball 76 on roller 77. The roller is rotating in a direction to oppose the motion of the incoming substrate with a small friction force. However, this fric~ion force is small enough so as to allow the incoming substrate to be forced through the nip. After the last portion of the substrate passes 5 through the input nip, the friction force from the ball on roll nip forces thetrail edge of the incoming sheet to maintain contact with roller 70. This causes the trail edge to "walk around" to the exit nip formed between rollers 70 and 71. As soon as the substrate is under control of the exit nip, the next substrate can be fed into the inverter allowing simultaneous substrate 10 inversion.
While the inverter system disclosed herein is preferred, it will be appreciated that various alternatives, modifications, variations or improv~
ments thereon may be made by those skilled in the art, and the following claims are intended to encompass all of those falling within the true spirit 15 and scope of the invention.
Claims (9)
1. A substrate inverter, comprising: (a) inversion channel means; (b) input drive means having two drive rollers for driving a substrate into said channel means; (c) output drive means having two drive rollers, one of which is shared with said input drive means for driving a substrate out of said channel means; and (d) nip means for resisting substrate movement into said channel means located downstream of said input drive means a distance less than the length of said substrate so that a continuous drive force is applied to the substrate in a direction opposite to the initial incoming sheet direction after the substrate is driven into said nip means by said input means, said force maintaining said sub-strate in contact with said shared drive roller as the last portion of the substrate leaves said input means so that the force of said nip means will drive the substrate to said output means for movement out of said channel means.
2. The inverter of claim 1, wherein said inversion channel means includes buckle inhibitor means.
3. The inverter of claim 2, wherein said buckle inhi-bitor means comprises a pivotally mounted ski.
4. The inverter of claim 1, wherein said nip means comprises an idler ball and a drive roller.
5. The inverter of claim 4, wherein said idler ball is housed within an angled channel located within a support block.
6. The inverter of claim 1 wherein said nip means com-prises a roller mounted on a shaft and spring loaded against a drive roller.
7. A method for inverting a substrate comprising the steps of: driving a substrate into a channel with an input force, resisting the driving of said substrate into said channel with a continuous force less than said input force but large enough to move said substrate along said channel in the absence of said input force, and grasping said sheet and pulling it from said channel as said continuous force moves said sheet to an output position once the driving step has been completed.
8. The method of claim 7 wherein the resisting step is performed by positioning a drive nip along said channel a distance less than the length of said substrate so that said input force is resisted while said substrate is still being driven into said channel.
9. The method of claim 7 wherein during the transi-tion between said driving and grasping steps said substrate is re-oriented by contact with a drive roller which co-acts with the substrate in both the driving and grasping process.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US18291880A | 1980-09-02 | 1980-09-02 | |
| US182,918 | 1980-09-02 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1178304A true CA1178304A (en) | 1984-11-20 |
Family
ID=22670620
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000381861A Expired CA1178304A (en) | 1980-09-02 | 1981-07-16 | Retard drive inverter |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JPS5777154A (en) |
| CA (1) | CA1178304A (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6212569A (en) * | 1985-07-09 | 1987-01-21 | Konishiroku Photo Ind Co Ltd | Both side copying device |
| JPS6229360U (en) * | 1985-08-07 | 1987-02-21 | ||
| JPH089099Y2 (en) * | 1986-09-20 | 1996-03-13 | ニスカ株式会社 | Sheet transport device |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB138945A (en) * | 1918-05-21 | 1920-02-26 | Mike Sroke | Improvements in and relating to bayonet for rifles |
| JPS4962212A (en) * | 1972-10-18 | 1974-06-17 | ||
| NL7612692A (en) * | 1976-11-16 | 1978-05-18 | Oce Van Der Grinten Nv | DEVICE FOR COPYING SHEET ORIGINALS. |
| JPS5642292Y2 (en) * | 1977-03-08 | 1981-10-02 | ||
| JPS5470562A (en) * | 1977-11-17 | 1979-06-06 | Ricoh Watch | Apparatus for changing direction of sheet conveyance |
| US4214740A (en) * | 1978-05-02 | 1980-07-29 | Xerox Corporation | Sheet reversing mechanism |
-
1981
- 1981-07-16 CA CA000381861A patent/CA1178304A/en not_active Expired
- 1981-08-27 JP JP13479581A patent/JPS5777154A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPH059346B2 (en) | 1993-02-04 |
| JPS5777154A (en) | 1982-05-14 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4359217A (en) | Inverter with proportional force paper drive | |
| US4346880A (en) | Apparatus for inverting substrates | |
| US4487506A (en) | Reversing roll inverter with bypass capability | |
| EP0576235B1 (en) | Orbitting nip plural mode sheet output with faceup or facedown stacking | |
| US4744555A (en) | Sheet transport and registration apparatus | |
| US4166614A (en) | Jogging and normal force for sheet feeding | |
| US4365794A (en) | Toggle arm inverter | |
| US4673176A (en) | Soft nip damping inverter | |
| EP0494108B1 (en) | A multiple output sheet inverter | |
| GB1605088A (en) | Document handling | |
| US6341777B1 (en) | Multiple-position idler roller | |
| US5141215A (en) | Sorter-finisher provided for an image forming apparatus | |
| EP0047181B1 (en) | A substrate inverter | |
| US4487407A (en) | Trail edge copy registration system | |
| US5166738A (en) | Copier operable in two-sided and combination copy modes | |
| EP0534781B1 (en) | Inverter | |
| US6808171B2 (en) | Inverter having a slow speed drive mode for improved reliability | |
| US5449160A (en) | Gateless rocker inverter | |
| US5048817A (en) | Dynamic edge guide for side registration systems | |
| US5449163A (en) | Full productivity high performance inverter | |
| CA1178304A (en) | Retard drive inverter | |
| USRE33843E (en) | Sheet transport and registration apparatus | |
| US5133539A (en) | Sorter-finisher provided for an image forming apparatus | |
| EP0289217B1 (en) | Sheet transporting apparatus | |
| JPH0826563A (en) | Aftertreatment device for sheet |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |