Data processing: generic control systems or specific application – Specific application – apparatus or process – Article handling
Reexamination Certificate
2000-08-29
2002-10-29
Walsh, Donald P. (Department: 3651)
Data processing: generic control systems or specific application
Specific application, apparatus or process
Article handling
Reexamination Certificate
active
06473674
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a multiple feed detection device for detecting a feed of two or more overlapped sheets (multiple feed) when sheets are carried along a carriage path, and more particularly to a method and a device for detecting a multiple feed suitable for the multiple feed detection of prints.
2. Description of the Related Art
A collator shown in
FIGS. 8
,
9
A, and
9
B is known as an apparatus for collating a plurality of different prints by overlapping them one by one from the first page to make bundles of a desired number of copies of the prints.
FIG. 8
shows an external view illustrating an entire collator,
FIG. 9A
shows a partially enlarged sectional view of each bin taken from
FIG. 8
, and
FIG. 9B
shows a view illustrating each bin as viewed in the direction indicated by the arrow A in FIG.
9
A. In
FIG. 8
, arrows indicate the flow of sheets for each bin.
A collator
1
comprises a plurality of bins (
10
bins in an example of
FIG. 8
)
2
in which different prints (sheets) are to be set. The bins
2
(
2
1
to
2
10
) are arranged in parallel in spaced apart relation provided vertically with respect to a body
3
and disposed to be protruded with a predetermined distance from the front surface of the body
3
.
A sheet discharge tray
5
for collating and discharging prints
4
which are fed from each bin
2
one by one is disposed to be protruded with a predetermined distance from the front surface of the body
3
at the lowest part of the body
3
. A carriage mechanism is provided inside the body
3
, e.g., carrier rollers or carrier belts for carrying the prints
4
fed from each bin
2
onto the sheet discharge tray
5
.
Each bin
2
comprises a sheet feed base
6
on which the prints
4
are set. The sheet feed base
6
includes a fixed part
6
a
and a movable part
6
b
which is vertically movable by a shift mechanism driven by a motor (not shown). A sheet-detecting sensor
7
for detecting any presence of the prints
4
to be set, e.g., a reflector-type sensor, is disposed in the movable part
6
b
. A sheet feed fence
8
movable in accordance with the size of the prints
4
to be set is disposed on the sheet feed base
6
. The sheet feed fence
8
in
FIG. 9B
is provided to be fixed at the right side and movable in accordance with the size (width) of the prints at the left side.
A sheet feed roller
9
and a handling plate
10
for carrying the prints
4
set on the sheet feed base
6
one by one from the top to the body
3
are provided to be opposed to one another in each bin
2
. Auxiliary rollers
11
for keeping the prints
4
, e.g., from being curled, are disposed at both sides of the sheet feed roller
9
. The rotation axis
12
of the sheet feed roller
9
and the auxiliary rollers
11
is connected through a sheet feed clutch
13
to a main motor (drive motor
26
). The sheet feed roller
9
and the auxiliary rollers
11
rotate by means of drive of the main motor in a clockwise direction in FIG.
9
A.
Multiple feed sensors
15
as a sheet detector for detecting a multiple feed of the prints
4
to be fed are disposed around a carriage path between the sheet feed roller
9
of each bin
2
and the carriage mechanism of the body
3
.
The multiple feed sensors
15
are constituted by a transmission-type of optical sensors comprising a light emitting sensor
15
a
and a light receiving sensor
15
b
. The light emitting sensor
15
a
is, for example, constituted by a light emitting diode, a laser diode, or a lamp. The light emitting sensor
15
a
is disposed at a predetermined distance apart from the carriage path
16
along which the prints
4
are fed.
The light receiving sensor
15
b
is, for example, constituted by a photodiode. The light receiving sensor
15
b
is disposed to be opposed to the light emitting sensor
15
a
at a predetermined distance apart from the carriage path
16
, e.g., in an equally spaced apart relation between the light emitting sensor
15
a
and the carriage path
16
such that the carriage path
16
on which the prints
4
are fed is sandwiched between the sensors.
At the position of the multiple feed sensor
15
, if the prints
4
are not carried, the light emitted from the light emitting sensor
15
a
is directly received by the light receiving sensor
15
b
, whereas if the prints
4
are carried, the light transmitted through the prints
4
is received by the light receiving sensor
15
b.
In the collator
1
as constituted above, when the prints
4
having pages
1
to
10
are respectively set to the bins
2
1
to
2
10
in order, e.g., the prints
4
of page
1
to
2
1
, the prints
4
of page
2
to
2
2
, the prints
4
are fed one by one subsequently from the bin
2
1
positioned in the highest part, and discharged onto the sheet discharge tray
5
. This allows the collated prints
4
to be discharged as a copy of the pages
1
to
10
onto the sheet discharge tray
5
.
Each of the prints
4
set in each of the bins
2
is fed inside the body
3
through the following states: that is, the state where it is approaching carrier rollers
17
of the carriage mechanism of the body
3
as shown in
FIG. 01A
, the state where it has reached the carrier rollers
17
and a loose is then produced as shown in
FIG. 10B
, the state where it is pressed by the sheet feed roller
9
and the carrier rollers
17
so that the position of it passing between the multiple feed sensors
15
is fixed as shown in
FIG. 10C
, and the state where the end thereof leaves the sheet feed roller
9
and thereby rises upward.
In the collator
1
as constituted above, conventionally, when detection is conducted for the multiple feed of the prints
4
fed from each of the bins
2
, a detection method has been employed in which the maximum value of the light transmission quantity of the prints
4
being passed is measured while the prints
4
pass through between the multiple feed sensors
15
, and the maximum value is compared to a reference value.
However, in the conventional method as stated above, when the maximum value of the light transmission quantity of the prints
4
being passed is measured, a slack of the prints may develop as shown in
FIG. 10B
, and a springing of the prints may develop as shown in FIG.
10
D. Therefore, the position of the sheet passing between the multiple feed sensors deviates from a predetermined position, thereby causing an increase in the light transmission quantity compared to the real one.
FIG. 11
illustrates an example of the light transmission quantity of the prints at the time of the sheet feed. This shows that when the slack or springing of the prints
4
develops as shown in
FIGS. 10B and 10D
, the light transmission quantity of the prints
4
drastically changes as shown in respective regions (i) and (ii) in
FIG. 11
so that it cannot be stable.
Therefore, the conventional method as stated above may have caused a problem in that if the light transmission quantity of the prints
4
, when the slack or springing of the prints
4
develops as shown in
FIGS. 10B and 10D
, is measured as the maximum value, the measured value is not less than a reference value even when a multiple feed really occurs, thereby causing misdetection.
Instead of the above method, it is known to use a method in which an average value of the light transmission quantity for a certain extent in area of the print is calculated and then the calculated average value is compared with a reference value.
However, in this method, when the level of the darkness of the printed portion is high or the rate of the printed portion to the whole area is high, as will be explained in the following examples 1 to 4 (
FIGS. 12
to
15
), a difference between the average values of the single feed and the multiple feed becomes smaller, thus causing a lower degree of accuracy for the detection.
EXAMPLE 1
As shown in
FIG. 12
, if the frequency at the light transmission quantity of 100 for the underlying portion of the prints is 50 and the frequency at the light transmission quantity
Butler Michael E.
Nath Gary M.
Nath & Associates PLLC
Novick Harold L.
Riso Kagaku Corporation
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