Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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BACKGROUND OF THE INVENTION
The development of high speed electrostatic
reproduction machines has brought about the need for simple,
yet reliable means for registering and conveying sheets or
documents through the reproduction machine. This is especially
true in the case of automatic document handlers wherein the
document to be copied must be rapidly and carefully presented
to the platen of the copy maehine in proper registration and
then removed therefrom. In electrostatic machines such as
the xerographic type disclosed in U. S. Patent No. 3,674,363 to
Bayler et al, the documents to be reproduced are placed in an
automatic document handler which sequentially feeds documents
to the platen of the machine. After exposure, the device
removes the copied documents and feeds the succeeding document
to the platen for eopying. Dependable apparatus for earrying
out this function of plaeing documents on the seanning platen
eonstitutes eonvenienee to an operator who would otherwise
have to manually ehange the doeument and, at the same time,
inereases the effieieney of the eleetrostatic reproduetion
system by permitting more copies to be made in a given time.
Generally speaking, sheet feeding devices for
transporting sheets or doeuments singly from a stack to a
work station are known in the art. However, known sheet
feeding devices are inadequate for dependably keeping paee
with the great speed at which electrostatie maehines now
operate. When deviees for singly advancing sheets from a
stack are designed to operate at higher speeds, a great number
of problems are encountered in attempting to deskew, register,
and convey the sheet to a precise position at a work station
such as the platen of the reproduction maehine.
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A number of devices have been utilized in the past
to properly locate a document on the platen of a copy macnine.
For example, in U.S. Patent 3,790,158 there is disclosed a
mechanism wherein the document is fed in a forward direction
onto the platen of a copy machine and thereafter reversed
against a registration edge to deskew and register the document.
Problems may be encountered in the mechanism required to move
the registration edge into and out of the document path or
the sensors actuating the mechanism. Further, in positively
driving the document against the registration edge while it is
firmly pressed between the transport belt and the platen, the
amount of deskewing that can be accomplished may be insufficient
due to the frictional engagement between the document and the
transport belt. Another type of locating system that has been
utilized in the past is disclosed in the aforementioned
U.S. Patent No. 3,674,363 wherein the passage of the document
past a certain point in the document path actuates a switch,
which, in conjunction with the time delay, inactivates the
document transport mechanism when the document is in the
desired position on the platen.
Another method to present documents to the platen of
a copy machine would be through the use of mechanical type
gripper bars which would be employed to grip the leading edge
of a document and thereafter positively transport the document
to the proper location on the platen. However, ordinary
grippers of necessity include a number of precision mechanical
elements adapted for opening and closing the gripper fingers
and moving the gripper bars through the desired path.
SUMMARY OF THE INVENTION
This invention provides a sheet handling mechanism
for deskewing, registering and transporting individual
sheets of material comprising:
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a movable endless belt having a plurality of
flexible tabs ormed thereon projecting substantially
normal to the belt surface, the tabs extending across
the belt in a direction perpendicular to the direction
of belt travel and being adapted for deformation into
a horizontal position overlying the adjacent belt
surface;
support means having a surface disposed opposite
the belt for cooperation therewith, contact of the
tabs with the surface of the support means causing the
tabs to deform against the surface of the belt; and
sheet supply means for conveying individual sheets
of material to the belt, said sheet supply means being
adapted to overdrive the individual sheets of material
against the ~abs to cause the sheet to be deskewed there-
against, movement of the belt relative to the support
means causing the tabs to be deformed toward the surface of
the belt to positively grip the lead edge of the individual
sheets of material between the tab and the belt surface for
subsequent transport of the individual sheets of material by
the belt across said support means.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a schematic illustration of a document
feeding mechanism employing the deskewing, registering, and
conveying belt of the present invention;
Figure 2 is an enlarged section of a portion of the
belt and platen surface illustrated in Figure 1.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to the drawings, there is illustrated an
automatic document handler including a document supply tray 2
adapted for receiving a plurality of document~ 4 to be fed to
the platen 6 of a copy machine. While the copy machine per se
is not illustrated, it should be understood that any suitable
copy machine such as that illustrated in the aforementioned U.S.
Patent 3,674,363 could be utilized therewith. The document
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handler includes a separating roll 8 adapted to remove documents
individually from the bottom of the stack of documents 4 and
forward individual documents to a take-away roll pair 10
which is adapted to forward the single document to a suitable
platen belt 12. The belt 12 preferably comprises a single
wide belt adapted to completely overlie the platen 6. The belt
12 is supported for movement on main support rolls 14 and 16,
roll 16 being driven by a suitable motor 18 for moving the belt
12 relative to the platen 6. A plurality of bias rollers
20 may be provided to maintain the belt 12 against the platen 6
and thereby assure intimate contact of the document fed
therebetween during the exposure or copying operation. Platen
belt 12 is provided with a plurality of flexible projections
22 suitably formed thereon, as by molding, for reasons to be
hereinafter explained. The document, after the copying
operation is completed, is fed out from beneath belt 12 into
document catch tray 24. While the document feeder illustrated
is a single path document feeder, i.e., the documents are fed
from a first tray through the copying operation to an output
tray, it should be understood that suitable means could be
provided through a second path to return the documents to
tray 2 for repetitive recirculation thereof across platen 6.
Considering the operation of the illustrated document
handler, upon initiation of the copy cycle, separator roll 8
and take-away roll pair 10 would be actuated to feed a document
S from tray 2 to the platen belt 12. The rolls 8 and 10 are
adapted to overdrive the document slightly against projections
22 to form a buckle in the document as illustrated in Figure 1.
This provides a positive deskewing action to assure proper
alignment of the document on the platen when it is transported
thereon by the belt 12. It should be understood that as the
buckle is forming in the document, the belt 12 is also moving,
albeit at a slightly slower speed than the document. Referring
to Figure 2, which illustrates a small section of platen 6
and belt 12, it can be seen that as the belt moves across
platen 6, the tab 22 is deformed against the bottom surface of
the document S to positively grip the lead edge of the document
for movement across the platen 6. Suitable means such as a
microswitch 24 is provided to stop motor 18 and the belt 12
driven thereby when the document S carried by the belt is in
the proper copying position on the platen.
In the embodiment illustrated, one of the tabs 22
is utilized for contacting the microswitch to inactivate the
motor 18 although it should be understood that a variety of
position sensors could be substituted therefore such as
photosensors acting in conjuction with openings formed along
one edge of the belt etc. When the copying cycle is completed
the apparatus is again energized to carry the copied document
off the platen and present the subsequent document from document
tray 12 onto the platen for copying thereof.
While the invention has been described with reference
to the structure disclosed, it is not confined to the details
set forth, but is intended to cover such modifications or
changes as may come within the scope of the following claims.
