Sheet feeding or delivering – Feeding – Separator and conveyor
Reexamination Certificate
1999-03-30
2001-02-13
Skaggs, H. Grant (Department: 3651)
Sheet feeding or delivering
Feeding
Separator and conveyor
C271S010030, C271S010050, C271S094000, C271S096000, C271S031100
Reexamination Certificate
active
06186491
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a sheet feeding apparatus and, more particularly, to a sheet feeding apparatus for feeding out mail items having different sizes, weights, and shapes one by one.
As an example of a conventional sheet feeding apparatus, a sheet extracting apparatus described in Japanese Patent Laid-Open No. 6-71227 (Reference 1) is known.
Reference 1 describes a technique for extracting sheets by utilizing the negative pressure of a negative pressure chamber. Reference 1 also describes a technique for measuring the pressure in the negative pressure chamber with a pressure sensor and informing an abnormality when the value of the pressure sensor becomes less than a predetermined value, and a technique for blocking the flow of air to the negative pressure chamber with a relief valve connected to the negative pressure chamber, when no mail exists, to decrease noise.
FIG. 4
shows the schematic arrangement of the conventional sheet extracting apparatus described in Reference 1. The sheet extracting apparatus shown in
FIG. 4
comprises a suction belt
60
for supplying a mail item
58
, a negative pressure chamber
62
close to the suction belt
60
to receive a negative pressure, an air pipe
64
connected to the negative pressure chamber
62
, a relief valve
66
for controlling the negative pressure of the negative pressure chamber
62
, an air filter
68
for removing dust and the like in the air, and a blower
70
for generating a negative pressure.
A pressure sensor
72
for detecting the pressure is placed in the negative pressure chamber
62
, and a mail sensor
74
for detecting the presence/absence of a mail item is placed at a position where the mail item
58
is placed. Outputs from the sensors
72
and
74
are input to a CPU (Central Processing Unit)
76
having an air pressure determining section
76
a. The CPU
76
is connected to a valve controller
78
for controlling the relief valve
66
, and a display
82
and a voice guide
84
that constitute an informing unit
80
for informing the operator of the state of the apparatus.
The operation of the sheet extracting apparatus having the above arrangement will be described.
Usually, the mail items
58
are drawn by the suction belt
60
with the negative pressure of the negative pressure chamber
62
one by one, and each mail item is fed by the suction belt
60
in the convey direction. With a lapse of a predetermined period of time since the start of operation of the apparatus, if the mail sensor
74
determines that no mail item
58
has been fed to the suction belt
60
for a predetermined period of time or more, the CPU
76
controls the valve controller
78
to diagnose the apparatus by utilizing the idling time during which no mail item is fed. Thus, the relief valve
66
is closed to set the interior of the negative pressure chamber
62
at a negative pressure.
The state in the negative pressure chamber
62
is detected by the pressure sensor
72
. The CPU
76
compares the detected pressure and a normal-state pressure with the air pressure determining section
76
a
. The CPU
76
determines whether the comparison result is less than a predetermined value. If the comparison result is less than a predetermined value, the CPU
76
drives the display
82
and voice guide
84
of the informing unit
80
to inform the operator of an abnormality.
From the detection result of the mail sensor
74
, if no mail item
58
is placed in front of the suction belt
60
, the relief valve
66
is switched to an open state to release the pressure, so the interior of the negative pressure chamber
62
does not become a negative pressure. This aims at preventing the interior of the negative pressure chamber
62
from becoming a negative pressure to generate air suction noise.
In the conventional sheet extracting apparatus described above, when sheets such as mail items having largely different sizes, weights, and shapes are to be extracted by suction one by one, sometimes a particularly heavy mail item is not reliably drawn by suction with the rotating suction belt
60
. In this case, the suction belt
60
performs idling and does not feed a mail item, or a mail item is conveyed while slipping on the suction belt
60
. Then, an interval cannot be maintained between the currently fed mail item and a mail item which is to be extracted next.
This is because, when feeding the mail, the suction belt
60
is continuously rotated at a constant speed without stopping. Another reason is as follows. The pressure in the negative pressure chamber
62
is measured by the pressure sensor
72
. If the measurement result is less than a predetermined value, it is utilized for only informing the operator of the abnormality of the suction portion including the negative pressure chamber.
In the conventional sheet extracting apparatus described above, when one mail item is extracted and thereafter the next mail item is to be extracted, the next mail item is sometimes fed at an earlier timing than usual. In this case, the next mail item overlaps the current one to be conveyed together with it.
This is due to the following reason. Since the relief valve
66
is not turned on/off every time one mail item is fed, the interior of the negative pressure chamber
62
is always at a negative pressure, and accordingly a force for drawing the mail item by suction is always effected.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a sheet feeding apparatus in which, when feeding sheets having largely different sizes, weights, and shapes, the sheets can be drawn with a suction belt reliably, and can be stably fed one by one.
It is another object of the present invention to provide a sheet feeding apparatus in which a sheet is prevented from being fed at an earlier timing than usual, thereby preventing double feeding.
In order to achieve the above objects, according to the present invention, there is provided a sheet feeding apparatus comprising a sheet feed portion for feeding a plurality of sheets of different sizes in a direction of thickness thereof in an upright state, a suction belt having a belt hole for drawing each sheet fed from each sheet feed portion by suction, so as to feed out the sheet drawn by suction with the belt hole, drive means for driving the suction belt, negative pressure generating means for generating a pressure for drawing the sheet by suction in the belt hole, opening/closing means for applying/stopping applying the negative pressure from the negative pressure generating means to the belt hole, a pressure sensor for measuring a pressure in the belt hole, a first detection sensor for detecting the sheet fed out by the suction belt, a second detection sensor for detecting the belt hole after the sheet is fed out, and control means for controlling operations of the opening/closing means and the drive means on the basis of detection outputs from the pressure sensor and the first and second detection sensors.
REFERENCES:
patent: 3504909 (1970-04-01), Burkhardt
patent: 3599967 (1971-08-01), Rapparlie et al.
patent: 4018434 (1977-04-01), Mitchell et al.
patent: 4030723 (1977-06-01), Irvine et al.
patent: 5090676 (1992-02-01), Matsuno et al.
patent: 5391051 (1995-02-01), Sabatier et al.
patent: 0 333 171 (1989-03-01), None
patent: 000507661A1 (1992-10-01), None
patent: 51-43195 (1974-09-01), None
patent: 61-160121 (1986-10-01), None
patent: 64-7138 (1989-01-01), None
patent: 1-187137 (1989-07-01), None
patent: 3-166159 (1991-07-01), None
patent: 6-71227 (1994-03-01), None
patent: 6-28504 (1994-08-01), None
patent: 8-12109 (1996-01-01), None
Patent Abstracts of japan, vol. 18, No. 322 (C-1214), Jun. 20, 1994.
Nakabayashi Isamu
Tomiyama Katsuya
NEC Corporation
Skaggs H. Grant
Sughrue Mion Zinn Macpeak & Seas, PLLC
LandOfFree
Sheet feeding apparatus does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Sheet feeding apparatus, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Sheet feeding apparatus will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2608926