Sheet feeding or delivering – Delivering – With transfer means between conveyor and receiver
Reexamination Certificate
1999-06-21
2001-03-13
Walsh, Donald P. (Department: 3653)
Sheet feeding or delivering
Delivering
With transfer means between conveyor and receiver
C271S216000, C271S266000, C271S202000, C271S151000, C271S185000, C271S003150
Reexamination Certificate
active
06199858
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to a method and apparatus for stacking sheets, for example for use in reproduction apparatus such as electrostatic reproduction apparatus.
BACKGROUND OF THE INVENTION
There are many applications in which sheets must be fed singly from a stack to a downstream position. One important application is in reproduction apparatus such as electrostatic reproduction apparatus in which blank sheets are held in a stack and then fed singly through the apparatus to a reproduction station where an image is transferred onto the sheet, the sheet then being fed on to an outlet. A further example is a duplex tray within reproduction apparatus for use when images are to be reproduced on both sides of the sheet. In this situation, a blank sheet is fed to the reproduction station so that an image can be reproduced on one side of the sheet, the sheet then being fed to a temporary storage location defined by a duplex tray where the sheet can be flipped in its orientation and then drawn out and fed back through the reproduction station so that a further image can be reproduced on its other side.
In all applications where sheets are to be fed singly from a stack, it is important to prevent more than one sheet being fed simultaneously. Conventionally, this is achieved by using counter running rolls or nips and the like.
SUMMARY OF THE INVENTION
In accordance with one aspect of the present invention, there is provided an apparatus for feeding sheets, comprising a belt transport, defining a surface movable in a process direction. A first pair of rollers, defining a dispense nip, is disposed upstream of the belt transport in the process direction. A second pair of rollers, defining a feeder nip, is disposed downstream of the belt transport in the process direction. A control causes feeding of a leading edge of a first sheet a predetermined short distance through the dispense nip, and then feeds leading edges of each of a plurality of subsequent sheets a predetermined short distance through the dispense nip, thereby causing respective leading edges of the first sheet and subsequent sheets to be spaced by the predetermined short distance as the plurality of sheets are fed through the dispense nip and placed on the belt transport. The control further causes the rollers forming the feeder nip to draw a leading edge of a sheet when the leading edge of the sheet enters the feeder nip from the belt transport.
In this invention, a stack of sheets is generated in which the sheets are already shingled or overlap and are not exactly aligned. This then enables downstream feed systems to be considerably simplified since a simple feed roller or belt can be arranged to engage just the leading most sheet in the shingled stack without any danger of also engaging other sheets in the stack. Typically, the remaining sheets in the stack will be held relatively tightly while the leading most sheet is fed forward.
Conveniently, a sheet in the temporary storage position lies in a plane with a vertical component. This orientation reduces storage space requirements but also allows sheets to be delivered to the temporary storage position from above, in which case the method may comprise moving a trailing end of a sheet into alignment with the dispense nip. This movement can be a simple flipping of the sheet from one orientation to the other typically from, to or through a vertical orientation.
The method preferably comprises holding the sheet in the temporary storage position using a feed nip, the feed nip being activated to feed the sheet to the dispense nip. However, the temporary storage position may provide a simple fixed base against which sheets lodge with a separate feed system for feeding sheets to the dispense nip.
The dispense nip itself can be defined by one or more cooperating pairs of rollers, belts or any other conventional apparatus.
The amount of overlap can be chosen depending upon the application. Typically, a relative displacement of about 10 mm will be used although the displacement could be increased to 20 mm or more.
REFERENCES:
patent: 5088711 (1992-02-01), Newsome
patent: 5842696 (1998-12-01), Haan et al.
Hutter R.
Miller Jonathan R.
Walsh Donald P.
Xerox Corporation
LandOfFree
Office printing apparatus with shingling of sheets in a... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Office printing apparatus with shingling of sheets in a..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Office printing apparatus with shingling of sheets in a... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2437081