Sheet feeding or delivering – Feeding – Multiple supplies
Reexamination Certificate
2002-10-25
2004-07-20
Walsh, Donald P. (Department: 3653)
Sheet feeding or delivering
Feeding
Multiple supplies
C271S009120, C400S584000
Reexamination Certificate
active
06764070
ABSTRACT:
TECHNICAL FIELD
The present invention relates generally to a sheet accumulating system and, more particularly, to a sheet accumulating system that uses a continuous web cutter for providing cut sheets and a right-angle transport device for stacking the cut sheets.
BACKGROUND OF THE INVENTION
Continuous web cutters are known in the art. A typical continuous web cutter is shown in FIG.
1
.
FIG. 1
shows a mass mailing insertion machine
1
, which uses a continuous web cutter
10
to cut a continuous web of material
20
into cut sheets, and provide the cut sheets to a sheet accumulator
60
via a right-angle transport device
50
. The cut sheets are accumulated into stacks in the sheet accumulator
60
and the stacks are inserted into envelopes in an envelope insertion station
70
. As shown in
FIG. 1
, a continuous web of material
20
with sprocket holes on both side of the web
20
is fed from a fan-fold stack
18
into the web cutter
10
, which has two moving belts with sprockets
12
(or tractors with pins) to move the web
20
toward a guillotine cutting module
16
for cutting the web
20
cross-wise into separate sheets. Perforations
30
(see
FIG. 2
a
) are provided on each side of the web material
20
so that the sprocket hole sections of the web
20
can be removed from the sheets prior to moving the cut sheets to other components of the mailing insertion machine
1
. In particular, the continuous web cutter
10
, as shown in
FIG. 1
, is used to feed two webs
22
,
24
of material linked by a center perforation
26
. As shown, a splitter
14
is used to split the linked webs
22
,
24
into two separate webs before the webs can be simultaneously cut by the cutting module
16
into two cut sheets
42
,
44
, as shown in
FIG. 2
a
. This type of web cutter is also known as a 2-up cutter. As shown in
FIG. 2
a
, the sheets
42
,
44
are moved substantially along a direction
102
toward a right-angle transport device
50
so that both sheets are moved along the same line in a different direction
104
as they exit the right-angle transport device
50
.
Right angle transport devices are known in the art. For example, Auerbach et al. (U.S. Pat. No. 5,664,772) discloses a right-angle transport device having two or more sheet turn-over modules, wherein the turn-over modules are placed at 45 degrees in the path of two or more sheets moving in a side-by-side fashion so that these sheets are turned over while their moving direction is changed by 90 degrees. Two turn-over modules
52
,
54
are shown in
FIG. 2
a
. Before encountering the turn-over modules
52
,
54
, the cut sheets
42
and
44
are moving side-by-side at the same speed, with their leading edges
142
,
144
substantially in-step with each other. However, after emerging from the turn-over modules
52
,
54
, as shown in
FIGS. 3
d
and
3
e
, the cut sheet
42
leads the cut sheet
44
by a distance D. This is because the two cut sheets
42
,
44
travel on two different paths. As shown in
FIG. 2
b
, the cut sheet
42
travels on a shorter inner path
112
, while the cut sheet
44
travels on a longer outer path
114
. The length of the outer path
114
(from X′ to M) is greater than the length of the inner path
112
(from X to M) by a distance OM, which is substantially equal to D.
FIGS. 3
a
to
3
e
illustrate how the turn-over modules
52
,
54
are used to change the direction of the cut sheets
42
,
44
so that they are moving substantially in the same path
116
, with one sheet leading another in an overlapping manner. As shown in
FIG. 3
a
, sheets
42
,
44
move at the same speed
106
toward the turn-over modules
52
,
54
along the first direction
102
. The length of the sheets
42
,
44
is denoted by the letter L and the width is denoted by the letter W. As shown in
FIG. 3
b
, part of the sheets
42
,
44
are turned over by the turn-over modules
52
,
54
and the turned over sections move along the second direction
104
, which is substantially perpendicular to the first direction
102
.
FIG. 3
c
shows that the sheets
42
and
44
are further engaged with the turn-over modules
52
,
54
. Because they move at the same speed
106
, the sheets
42
,
44
are turned over by the same amount. As the sheets
42
,
44
emerge from the turn-over modules
52
,
54
, they move substantially on the same line along the second direction
104
with the inner cut sheet
42
leading the outer cut sheet
44
. The sheets are partially overlapped with each other by an amount S, as shown in
FIG. 3
d
. The overlapped amount S is substantially equal to the difference between L and W. When the sheets
42
,
44
are completely disengaged from the turn-over modules
52
,
54
, they are overlapped by the same amount S, as shown in
FIG. 3
e
, if they are not moved by another moving mechanism in a different way.
The partially overlapped sheets
42
,
44
form a 2-sheet packet. The overlapped amount in this 2-sheet packet is essential for collation in the sheet accumulator
60
. If the difference between the length L and the width W of the sheets is very small, the small overlapped amount of the two cut sheets may cause a paper jam. If the width W is equal to or greater than L, then the sheets do not overlap with each other after they emerge from the turn-over modules
52
,
54
, which can cause problems in collation.
In order to achieve a desirable overlapped amount in a 2-sheet packet, Ifkovits et al. (U.S. Pat. No. 6,443,447) uses rollers of different speeds to separately drive the two cut sheets
42
,
44
toward the turn-over modules
52
,
54
. More specifically, the driving speed for the inner cut sheet
42
is lower than the driving speed for the outer cut sheet
44
. The use of different speeds would complicate the design of the mass mailing insertion machine because motors of different speeds are needed. Use of different speed motors in a higher velocity system is impractical because significant path length must be added to both paths in order to provide the design overlap.
Furthermore, in a mass mailing insertion machine, as shown in
FIG. 1
, the collation of sheets in the accumulator
60
requires that a minimum allowable gap is provided between two consecutive packets. The minimum allowable gap is determined by the time required for the trailing edge of the preceding packet to settle in the accumulator before the leading edge of the following packet arrives. The gap between consecutive packets is mainly determined by the cutter rate of the web cutter
10
and the moving speed of the cut sheets. In a machine, as disclosed in Ifkovits et al., if the speed for the inner path is 121 ips (inch per second) and the speed for the outer path is 144 ips, the inter-packet gaps at different cutter rates can be calculated as follows:
Cutter rate
Gap
Gap
(thousand per hour)
(inches)
(milliseconds)
25
4.34
30
27
2.79
19
30
0.86
6
36
−2.04
−14
Depending on an accumulator's design, it is generally desirable to have a minimum allowable gap of 2.94 inches or 20 ms between two consecutive packets. This gap is calculated by assuming that the sheets attain their velocity after they are cut by the cutting module
16
and driven by nips in the right-angle transport device
50
. Without the speed differential, the resulting gap for a 25K cutter operated at 144 ips would be 1.38 in (10 ms). In practice, the gap is somewhat non-deterministic due to the soft nips used in the web cutter and in the right-angle transport device. At any rate, while the machine as disclosed in Ifkovits et al. increases the inter-packet gap and helps solve the problem regarding the overlapped amount between two sheets in a packet, it is difficult to achieve a minimum allowable gap beyond the cutter rate of 27K.
It is advantageous and desirable to provide a method and device for increasing the overlapped amount of the cut sheets as they exit the right-angle transport device and, at the same time, increasing the inter-packet gap as the packets arrive in an accumulator.
SUMMARY OF THE INVENTION
It is a primary objective
Masotta John R.
Skinger Gregory P.
Sussmeier John W.
Wright William J.
Bower Kenneth W
Chaclas Angelo N.
Cummings Michael J.
Malandra, Jr. Charles R.
Pitney-Bowes Inc.
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