Sheet feeding or delivering – Feeding – Separators
Reexamination Certificate
2002-04-25
2003-12-16
Walsh, Donald P. (Department: 3653)
Sheet feeding or delivering
Feeding
Separators
C271S119000
Reexamination Certificate
active
06663098
ABSTRACT:
BACKGROUND
This invention relates generally to printing devices, and more particularly to techniques for handling media sheets during a pick process.
In a printing device, for example a printer partially shown in
FIG. 1
, a pick roller
101
picks a top sheet
111
atop a stack of media
109
accommodated in an input tray
107
of the printer. In addition, the pick roller
101
advances the top sheet
111
along a media path through a feed zone
113
in the printer for subsequently imprinting images on it. Due to the friction force between adjacent media sheets, several sheets next to the top sheet (hereinafter “next-to-top sheets,” not shown in
FIG. 1
) also leave the input tray
107
and follow the top sheet
111
into the feed zone
113
. To avoid such a multiple pick, where several sheets are picked and advanced through the feed zone, a separator
105
is mounted in the media path at the entrance
115
of the feed zone
113
approximately opposite the pick roller
101
for stopping further movement of at least part of the next-to-top sheets. Movements of the remaining part of the next-to-top sheets can be stopped by either the separator or printer structures located in the media path and before the separator in a media advancement direction.
To avoid affecting subsequent picks of sheets from the input tray during a printing operation, these next-to-top sheets that have moved out of the input tray
107
and stopped somewhere in the feed zone are supposed to be cleared from the feed zone before the next pick process starts. A conventional kicker
103
, which is mounted on the media path adjacent to an edge of the input tray and before the separator
105
in the media advancement direction, is commonly used to kick the next-to-top sheets back to the input tray
107
. Normally, such a conventional kicker
103
is made of rigid materials.
Additionally, the kicker is biased in a kicking position by a biasing spring (not shown) before a pick process starts. When the pick process starts, the kicker
103
is activated to move from the kicking position to an activated or feed position, in which the kicker
103
does not disturb the movements of the top sheet
111
or the next-to-top sheets. During the pick process, the kicker
103
will be kept in the feed position by the pick roller
101
or a kicker cam (not shown in
FIG. 1
) for a period until the leading edge of the top sheet has been fed into the feed zone
113
for a predetermined distance. Then the kicker
103
is released and moves back to the kicking position due to the biasing force to kick the next-to-top sheets back to the input tray
109
, which sheets have moved out of the input tray
109
and have stopped somewhere in the feed zone.
Note that in some designs as shown by
FIG. 1
, the conventional kicker
103
moves back to the kicking position when the trailing edge of the top sheet
111
has not yet passed the feed zone entrance
115
or the kicker
113
. The objective of this design is to try to kick the next-to-top sheets in the current pick process back to the input tray as soon as they are separated so as to avoid sheet-to-sheet dragging that could cause multiple pick. In that case, as shown in
FIG. 1
, the kicker
103
may interfere with the top sheet
111
being advanced through the feed zone
113
when the kicker
103
moves toward the kicking position. Such interference may increase the amount of stress on the top sheet
111
and therefore may degrade the printing performance. This is because the stress on the top sheet exists until the trailing edge leaves the kicker and may affect the linefeed of the top sheet and consequently the image quality of the top part of the printout. Additionally, the stress from the kicker is applied only at certain areas on the top sheet
111
where the interference occurs and is not uniformly distributed across the media width of the top sheet
111
. Thus, if the amount of stress is increased to a certain extent, the stress may cause the top sheet
111
to skew and affect its linefeed accuracy. As a result, the printing performance can be adversely affected.
There are ways of reducing the stress on the top sheet
111
caused by the interference between the kicker
103
and the top sheet
111
. For example, a kicker with a reduced length can be used to reduce the interference because normally a longer kicker will generate more interference. However, in most cases, the user may want the kicker to be as long as possible so as to cover a longer sweeping area. Reducing the length of the kicker may decrease its effectiveness.
Alternatively, the stress on the top sheet
111
can be reduced by reducing the biasing force applied to the kicker
103
, for example, by using a biasing spring with a lower stiffness, so as to reduce the kicking force exerted by the kicker
103
. However, reducing the kicking force may cause a less effective kick of the next-to-top sheets by the kicker
103
, especially if there is a heavy stack of next-to-top sheets.
Therefore, there is a need for an improved kicking mechanism in a printing device that effectively moves the next-to-top sheets back to the input tray with less interference between the kicking mechanism and the top sheet.
SUMMARY
According to the present invention, a kicker in a printing device is mounted adjacent an entrance of a feed zone where a pick roller is located for picking a top sheet from an input tray in a pick process. A plurality of next-to-top sheets next to the top sheet move out of the input tray and stop approximately at the entrance of the feed zone during the pick process. The kicker includes a relatively rigid base part for kicking a first portion of the next-to-top sheets back to the input tray and a flexible top part attached to the base part for kicking a second portion of the next-to-top sheets back to the input tray.
According to a second aspect of the invention, a media handling system in a printing device includes a pick roller for picking a top sheet from an input tray toward a print zone during a pick process and a kicker mounted adjacent the pick roller. A plurality of next-to-top sheets next to the top sheet are drawn out of the input tray and stop approximately at an entrance of the print zone during the pick process. Furthermore, the kicker includes a relatively rigid base part for kicking a first portion of the next-to-top sheets back to the input tray and a flexible top part attached to the base part for kicking a second portion of the next-to-top sheets back to the input tray.
According to a further aspect of the invention, a method is provided for kicking a plurality of next-to-top sheets back to an input tray in a printing device. The next-to-top sheets move out of the input tray and stop approximately at an entrance of a feed zone during a pick process. The method includes the steps of:
providing a kicker having a relatively rigid base part and a flexible top part attached to the base part;
kicking a first portion of the next-to-top sheets back to the input tray by using the base part of the kicker; and
kicking a second portion of the next-to-top sheets back to the input tray by using the top part of the kicker.
REFERENCES:
patent: 5764384 (1998-06-01), Wilcox et al.
patent: 6082729 (2000-07-01), Padget
patent: 6086062 (2000-07-01), Nakamura et al.
Chia Keng San
Chu Tzy Woei
Ng Chuah Fatt
Teo Cherng Linn
Kohner Matthew J.
Walsh Donald P.
LandOfFree
Compound kicker in media handling system does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Compound kicker in media handling system, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Compound kicker in media handling system will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3110659