U.S. patent application number 09/725653 was filed with the patent office on 2002-05-30 for varying velocity sheet handler.
Invention is credited to Quesnel, Lisbeth S..
Application Number | 20020063384 09/725653 |
Document ID | / |
Family ID | 24915447 |
Filed Date | 2002-05-30 |
United States Patent
Application |
20020063384 |
Kind Code |
A1 |
Quesnel, Lisbeth S. |
May 30, 2002 |
Varying velocity sheet handler
Abstract
A document creating apparatus comprising an image transfer
system and a transport system for transporting sheets of material.
The transport system has a first and second drive for moving the
sheets of material. A controller is connected to the first drive
and adapted to vary velocity of the first drive. While a sheet of
material contacts the first drive, the controller decreases the
velocity before the sheet of material contacts the second drive,
and increases the velocity after the sheet of material contacts the
second drive.
Inventors: |
Quesnel, Lisbeth S.;
(Pittsford, NY) |
Correspondence
Address: |
Christopher A. Hofmeister
Perman & Green, LLP
425 Post Road
Fairfield
CT
06430-6232
US
|
Family ID: |
24915447 |
Appl. No.: |
09/725653 |
Filed: |
November 29, 2000 |
Current U.S.
Class: |
271/270 |
Current CPC
Class: |
B65H 5/34 20130101 |
Class at
Publication: |
271/270 |
International
Class: |
B65H 005/34 |
Claims
What is claimed is:
1. A document creating apparatus comprising: an image transfer
system for transferring an image onto a sheet of material; and a
transport system for transporting the sheet of material along a
paper path, the transport system comprising: a first drive located
along the paper path for moving the sheet of material; a second
drive located along the paper path downstream from the first drive
for moving the sheet of material; and a controller connected to the
first drive and adapted to vary a drive velocity of the first
drive; wherein, while the sheet of material contacts the first
drive, the controller decreases the drive velocity of the first
drive before the sheet of material contacts the second drive, and
wherein the controller increases the drive velocity after the sheet
of material contacts the second drive.
2. The document creating apparatus of claim 1 wherein the image
transfer system comprises a printer.
3. The document creating apparatus of claim 1 wherein the image
transfer system comprises a xerographic toner depositor.
4. The document creating apparatus of claim 1 wherein the first
drive comprises a first idler roll and a first drive roll which
transports the sheet of material along the paper path with a
variable drive velocity.
5. The document creating apparatus of claim 4 further comprising a
motor connected to the first drive roll, wherein the motor is
adapted to variably drive the first drive roll.
6. The document creating apparatus of claim 1 wherein the second
drive comprises a second drive roll and a second idler roll wherein
the second drive roll is adapted to intermittent drive the sheet of
material along the paper path.
7. The document creating apparatus of claim 6 further comprising a
motor and a clutch connected to the second drive roll, wherein the
motor and the clutch are adapted to intermittently drive the second
drive roll.
8. The document creating apparatus of claim 1 further comprising a
sensor adapted to sense a leading edge of the sheet of material
before the sheet of material contacts the second drive.
9. A stalled roll registration system for use in a document
creating apparatus, the stalled roll registration system
comprising: a first drive for driving a sheet of material within a
paper path, the first drive comprising a first idler roll and a
first drive roll which drives the sheet of material with a variable
drive velocity; a second drive positioned downstream of the first
drive within the paper path, the second drive comprising a second
drive roll and a second idler roll with the second drive roll being
adapted for intermittent driving; and a controller connected to the
first drive and adapted to vary the drive velocity; wherein, while
the sheet of material contacts the first drive, the drive velocity
is decreased before the sheet of material contacts the second
drive, and wherein the drive velocity is increased after the
document sheet contacts the second drive.
10. A document creating apparatus comprising the stalled roll
registration system of claim 9 and a printer.
11. A document creating apparatus comprising the stalled roll
registration system of claim 9 and a xerographic toner
depositor.
12. The stalled roll registration system of claim 9 wherein the
first drive further comprises a motor connected to the first drive
roll, wherein the motor is adapted to drive the first drive roll
with a variable velocity.
13. The stalled roll registration system of claim 9 wherein the
second drive further comprises a motor and a clutch connected to
the second drive roll, wherein the motor and the clutch are adapted
to intermittently drive the second drive roll.
14. The stalled roll registration system of claim 9 further
comprising a sensor adapted to sense a leading edge of the sheet of
material before the sheet of material contacts the second
drive.
15. A method of moving a sheet of material in a document creating
apparatus comprising the steps of: driving a first drive at a first
drive velocity to move a sheet of material at a first speed; when a
leading edge of the sheet of material approaches a second drive,
decreasing velocity of the first drive to a slower second drive
velocity to thereby move the sheet of material at a slower second
speed before the sheet of material contacts the second drive; and
after the sheet of material contacts the second drive, increasing
velocity of the first drive to a third drive velocity which is
faster than the slower second drive velocity.
16. The method of claim 15 further comprising the step of sensing
the leading edge of the sheet of material before the sheet of
material contacts the second drive and while the sheet of material
contacts the first drive.
17. A method of copying an image comprising the method of claim 15
and the step of xerographic copying an image onto the sheet of
material before or after the sheet of material contacts the first
drive.
18. A method of printing an image comprising the method of claim 15
and the step of printing on the sheet of material before or after
the sheet of material contacts the first drive.
19. The method of claim 15 further comprising the step of driving
the second drive to move the sheet of material after the step of
increasing velocity of the first drive to the third drive velocity
which is faster than the slower second drive velocity.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a sheet moving system and,
more particularly, to a sheet moving system having a variable
velocity.
[0003] 2. Prior Art
[0004] Many different sheet registration devices are known in the
sheet feeding art. For example, U.S. Pat. No. 5,543,909 discloses a
stalled roll registration apparatus and method used as the sole
timing adjustment in a paper path which includes a clutch or motor
driven registration nip, a buckle chamber and two sensors. As
machine speed moves up, electronic registration methods are used
but can be costly in comparison to a stalled roll registration
apparatus and method. Electronic registration methods are used
because with the increase in machine speed, the velocity at which
the sheet impacts a registration nip in a stalled roll registration
apparatus is sufficient to damage the sheet or sufficient to push
the lead edge through the nip thereby degrading lead edge
registration performance. There is a desire to provide a sheet
moving system which provides an increase in machine speed but with
the use of a low cost stalled roll registration apparatus.
SUMMARY OF THE INVENTION
[0005] In accordance with one embodiment of the present invention,
a stalled roll registration system is provided for use in a
document creating apparatus. A first drive is provided that has an
idler roll and a drive roll for driving sheets of material at a
variable velocity. A second drive is positioned downstream of the
first drive that has an idler roll and a drive roll that is adapted
for intermittent driving. A controller is connected to the first
drive and adapted to vary the velocity. While the sheet of material
contacts the first drive, the drive velocity is decreased before
the sheet of material contacts the second drive, and the drive
velocity is increased after the sheet of material contacts the
second drive.
[0006] In accordance with another embodiment of the present
invention, a document creating apparatus is provided comprising an
image transfer system and a transport system for transporting
sheets of material. The transport system has a first and second
drive for moving the sheets of material. A controller is connected
to the first drive and adapted to vary velocity of the first drive.
While a sheet of material contacts the first drive, the controller
decreases the velocity before the sheet of material contacts the
second drive, and increases the velocity after the sheet of
material contacts the second drive.
[0007] In accordance with another embodiment of the present
invention, a method of moving a sheet of material in a document
creating apparatus is provided comprising a first step of driving a
first drive at a velocity to move the sheet. When a leading edge of
the sheet approaches a second drive, the first drive velocity is
decreased. After the sheet of material contacts the second drive,
the first drive velocity is increased.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] The foregoing aspects and other features of the present
invention are explained in the following description, taken in
connection with the accompanying drawings, wherein:
[0009] FIG. 1 is a schematic view of a document creating
apparatus;
[0010] FIG. 2 is a schematic elevation view of a xerographic
processing or printing section;
[0011] FIG. 3 is a schematic side view of a registration
system;
[0012] FIG. 4 is a schematic side view of a registration system
with a sheet of material approaching a second drive;
[0013] FIG. 5 is a schematic side view of a registration system
with sheet of material in contact with a second drive;
[0014] FIG. 6 is a time chart of the velocity of the first and
second drive rolls;
[0015] FIG. 7 is a time chart of the velocity of the lead edge of a
sheet of material.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0016] Referring to FIG. 1, there is shown, in schematic form, a
view of a document creating apparatus 2 for creating documents in
accordance with teachings of the present invention. Although the
present invention will be described with reference to the single
embodiment shown in the drawings, it should be understood that the
present invention can be embodied in many alternate forms of
embodiments. In addition, any suitable size, shape or type of
elements or materials could be used. A copying or printing system
of the type shown is preferably adapted to provide duplex or
simplex stacked document sets from duplex or simplex collated
document or print sets which result from either duplex or simplex
original documents or output document computer files for print.
[0017] Document creating apparatus 2, in the embodiment shown, is a
copier. However, in an alternate embodiment, the apparatus could be
a printer or any other suitable type of document creating
apparatus. Document creating apparatus 2 generally comprises a
xerographic processing or printing section 3, a finishing section 6
and an output section 9. Printing section 3 can be an
electrostatographic printing system such as made by Xerox
Corporation or alternately other xerographic or other type of
printing apparatus. Printing section 3 incorporates an image
transfer system and a transport system for transporting sheets of
material. Finishing section 6 may typically incorporate a hole
punch, a stapler, or any other suitable type of feature known in
the art. Output section 9 incorporates a tray 11 or a bin sorter
that accepts and stacks documents or document sets output from
finishing section 6 at output zone 12. Documents are printed or
copied in printing section 3 and output from printing section 3 to
finishing section 6. Documents can be sorted and bound at finishing
section 6. Document sets can be output from finishing section 6 at
output zone 12.
[0018] Referring now also to FIG. 2, there is shown is a schematic
elevation view of one embodiment of the xerographic processing or
printing section 3. The printing section 3 has a photoconductive
belt 14 that advances in the direction of arrow 16. Photoconductive
belt 14 passes through charging station 18 and exposure station 20
which is typically a raster output scanner that transmits a latent
image from controller 22 onto the photoconductive surface of
photoconductive belt 14. Controller 22 gets the image from raster
input scanner 24 that typically incorporates a CCD and scans an
image from document handler 26 Alternately, controller 22 gets the
image from a separate computer 28 when printing section 3 operates
as a printing device. Photoconductive belt 14 then advances to
development station 30 where toner is electrostatically attracted
to the latent image. Photoconductive belt 14 then advances to image
transfer station 32. A sheet of material 34 is advanced from sheet
stack 38 or sheet stack 40 by a sheet transport system 36 that
includes registration system 42. Registration system 42 has a first
drive 50 and a second drive 52 that is positioned downstream of
first drive 50. Sheet 34 is advanced to registration system 42 that
registers sheet 34 and then advances sheet 34 past image transfer
station 32 in a timed fashion. The toner deposited on the latent
image of photoconductive belt 14 is transferred to sheet 34 due to
sheet 34 becoming charged at image transfer station 32 and due to
sheet 34 being registered or timed relative to the latent image.
Sheet 34 is then advanced to fusing station 44 by belt 46 where the
toner image is permanently affixed to sheet 34, typically by
heating, thus creating a document sheet. Sheet 34 will either be
output to a finisher or a stacker or inverted at inverter 48 and
recirculated through the printing section to have a second image
deposited on its opposite side. Although the section 3 of the
apparatus 2 has been described in detail above, features of the
present invention could be used with other types of xerographic
processing or printing sections having any suitably blank paper or
sheet supply, created document output, image transfer system or
paper path. The description above is merely intended to be
exemplary. More or less features could also be provided. Although
registration system 42 is shown at a fixed position within the
copying or printing apparatus, this position is intended to be
exemplary and various alternative locations and modifications can
be devised by those skilled in the art without departing from the
invention. Such an alternative, for example, would be incorporating
registration system 42 at any point in the paper path of a copying
or printing apparatus where the paper path is either upstream or
downstream of the printing or copying operation. An additional
alternative, for example, would be incorporating belts instead of
rollers within registration system 42.
[0019] Referring now to FIG. 3, there is shown a schematic side
view of the registration system 42 incorporating features of the
present invention. Registration system 42 includes the first drive
50 and the second drive 52. First drive 50 has a first drive roll
62 and a first idler roll 64. Second drive 52 has a second drive
roll 66 and a second idler roll 68. In each instance, the idler and
drive rolls are urged against each other to allow sheets to be
moved by frictional engagement between them. First drive roll 62 is
driven by first motor 70. Controller 72 is connected to first motor
70. First motor 70 may be directly connected to first drive roll 62
or may be connected to additional drives or drive rolls in addition
to first drive roll 62. Through first motor 70, controller can vary
velocity 74 of first drive roller 62 either by varying the velocity
of first motor 70, by mechanical speed reduction as with gearing,
belt or a clutch, or otherwise. Second drive roll 66 is driven by
second motor 76, a clutch 78 can be attached between second motor
76 and second drive roll 66. Clutch 78 can be connected to
controller 72. Through clutch 78, controller 72 can intermittently
drive second drive roll 66 between a stalled state where second
drive roll 66 has zero velocity and a driving state where second
drive roll 66 has a fixed velocity after it initially accelerates
from the engagement of clutch 78. However, in an alternate
embodiment, the clutch might not be provided. The registration
system 42 further comprises a sheet sensor 82 baffles 86 and 88
which define a buckle chamber 89, and a buckle chamber sensor 91.
As the sheet 80 enters the registration system 42, it is contacted
by the two rolls 62, 64 of the first drive 50 and advanced by the
first drive along the paper path toward the second drive 52 as
indicated by arrow 90. Sheet of material 80 is driven by first
drive 50 at a velocity that is proportional to velocity 74.
Referring also to FIGS. 6 and 7, the velocities of the drive rolls
62, 66 and the lead edge 84 of the sheet 80 are shown on a time
chart. The velocity of the drive roll 62 initially starts at zero
and accelerates to a predetermined first velocity V1. Alternately,
the velocity of the drive roll 62 initially may be running at a
predetermined first velocity V1. The lead edge 84 of the sheet 80
enters the first drive 50 at time T1 and travels forward at
velocity V1. Referring also to FIG. 4, at time T2 sensor 82 is
triggered by the sheet 80. The sensor 82 could be any type of
suitable sensor, such as an optical sensor for example. Sensor 82
detects when sheet of material 80 passes it and sends a signal to
controller 72. Controller 72 is shown as a single controller, but
may alternately be individual controllers, or logic circuits or
part of an overall machine controller. Controller 72 reduces
velocity 74 of first drive roller 62 when sensor 82 detects lead
edge 84 as shown. Alternately, if sensor 82 is further upstream of
the paper path, controller 72 will reduce velocity 74 of first
drive roller 62 after a delay from the time when sensor 82 detects
lead edge 84 or trailing edge 96. In this manner, sensor 82 may be
placed upstream or downstream relative to drive roller 62. When
velocity 74 of first drive roller 62 is reduced to about velocity
V2, velocity of sheet 80 that is proportional to velocity 74 is
also reduced. As a result, the velocity of the lead edge 84 of
sheet of material 80 will be reduced to about V2 and the lead edge
84 of sheet of material 80 will not be damaged when it makes
contact with non-moving or stalled second drive 52.
[0020] Referring also to FIG. 5, sheet of material 80 is driven by
first drive 50 at velocity V2 past sensor 82 into second drive 52
while second drive 52 is in the stalled state. If sheet of material
80 was to contact non-moving or stalled second drive 52 at velocity
V1, lead edge 84 could be damaged. To reduce the risk of damage to
lead edge 84 at higher speed operation, the velocity of sheet of
material 80 is reduced to levels (i.e.: velocity V2) just before
lead edge 84 contacts the non-moving or stalled second drive 52
that do not produce damage to lead edge 84 as described herein.
Lead edge 84 of sheet of material 80 comes up against the
non-moving or stalled second drive 52 by time T3. Thus, at time T3
the velocity of the lead edge 84 has been reduced to zero. Because
lead edge 84 is stopped and the drive 50 is continuing to move the
sheet 80, the sheet buckles in the chamber 89. The sensor 91 can
sense when a predetermined sheet buckling has occurred, such as
disclosed in U.S. Pat. No. 5,775,690 which is hereby incorporated
by reference in its entirety. However, any suitable delay system or
system for activating the second drive 52 could be provided. After
time T3, the velocity of the drive roll 62 can remain at V2 or
start to increase back to Vi. At time T4, when the sensor 91 senses
that the predetermined sheet buckling has occurred (or an otherwise
delay from time T3), the controller 72 activates the motor 76 and
clutch 78 such that the velocity of the drive roll 66 increases
from zero towards V1. Through clutch 78, controller 72 can
intermittently drive second drive roll 66 between a stalled state
where second drive roll 66 has zero velocity and a driving state
where second drive roll 66 has an increased velocity after it
initially accelerates from the engagement of clutch 78.
[0021] Controller 72 is shown as a single controller, but may
alternately be individual controllers, or logic circuits or part of
an overall machine controller. After sheet of material 80 is
deskewed with second drive 52 as described herein, and sheet 80 is
registered or timed relative to the printing, copying or handling
operation then sheet 80 is advanced with second drive 52. At time
T5 the second drive roll 66 could reach velocity V1 and lead edge
84 would resume its movement at velocity V1. At time T6 (that may
occur after time T3 but before, during or after time T4) the
controller 72 could increase the velocity of drive roll 62 back to
V1. Controller 72 intermittently drives second drive roll 66 from
the stalled state where second drive roll 66 has zero velocity to a
driving state where second drive roll 66 preferably has a fixed
velocity 94 after it initially accelerates from the engagement of
clutch 78. In this manner, sheet 80 is driven and handled within
the printing, copying or handling operation in a registered and
deskewed fashion by registration system 56. Sheet of material 80 is
driven by first drive 50 past sensor 82 into second drive 52 while
second drive 52 is in the stalled state. Sensor 82 detects when
sheet of material 80 passes it and sends a signal to controller 72.
Sheet of material 80 is deskewed as the body of sheet of material
80 pivots about in the buckle chamber formed by baffles 86 and 88.
If sheet of material contacts non-moving or stalled second drive 52
at excessive speed, lead edge 84 could be damaged. To eliminate
damage to lead edge 84, while still maintaining higher speed
operation of the system, the velocity of sheet of material 80 is
temporarily reduced to levels that do not produce damage to lead
edge 84 just before lead edge 84 contacts the non-moving or stalled
second drive 52. To reduce the velocity of sheet of material 80 to
levels that do not produce damage to lead edge 84, controller 72
reduces velocity 74 of first drive roller 62 when sensor 82 detects
lead edge 84. Alternately, if sensor 82 is further upstream of the
paper path, controller 72 will reduce velocity 74 of first drive
roller 62 after a delay from the time when sensor 82 detects lead
edge 84 or trailing edge 96. In this manner, sensor 82 may be
placed upstream or downstream relative to drive roller 62. After a
period of time during which sheet of material 80 is deskewed and in
contact with non moving or stalled second drive 52 as described
herein, controller 72 increases velocity 74 of first drive roller
62. In this manner, lead edge 84 of sheet of material 80 will not
be damaged yet the apparatus incorporating registration system 42
may be operated at higher speed overall as compared to existing
stalled roll approaches. As a result, there is provided a sheet
moving system which provides an increase in machine speed, but with
the use of a low cost stalled roll registration apparatus such as
described by registration system 42.
[0022] It should be understood that the foregoing description is
only illustrative of the invention. Various alternatives and
modifications can be devised by those skilled in the art without
departing from the invention. Accordingly, the present invention is
intended to embrace all such alternatives, modifications and
variances which fall within the scope of the appended claims.
* * * * *