Information
-
Patent Grant
-
6299155
-
Patent Number
6,299,155
-
Date Filed
Tuesday, March 23, 199925 years ago
-
Date Issued
Tuesday, October 9, 200123 years ago
-
Inventors
-
Original Assignees
-
Examiners
Agents
- Sughrue, Mion, Zinn, Macpeak & Seas, PLLC
-
CPC
-
US Classifications
Field of Search
US
- 271 108
- 271 90
- 271 91
- 271 92
- 271 93
- 271 94
- 271 95
- 271 96
- 271 97
- 271 98
- 271 99
- 271 100
- 271 101
- 271 102
- 271 103
- 271 104
- 271 105
- 271 106
- 271 107
- 294 641
- 414 7521
- 248 2062
-
International Classifications
-
Abstract
An apparatus for feeding a sheet has a pair of suction cups movable into and out of a cassette, a displacing mechanism for displacing the suction cups between a position in the cassette and a sheet delivering mechanism to cause the suction cups to transfer a stimulable phosphor sheet from the cassette to the sheet delivering mechanism, and a piping system connecting the suction cups to a vacuum pump for attracting the stimulable phosphor sheet to the suction cups, and for ejecting air from the suction cups toward a surface to be attracted of the stimulable phosphor sheet when the suction cups are moved into the cassette. The stimulable phosphor sheet can smoothly and reliably be removed from the cassette while the suction cups are effectively prevented from being deformed.
Description
BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates to a method of and apparatus for feeding a sheet such as a photographic film, a stimulable phosphor sheet, etc., by smoothly and reliably attracting the sheet with suction cups.
There is known a system for recording radiation image information of a subject such as a human body with a stimulable phosphor, and reproducing the recorded radiation image information on a photosensitive medium such as a photographic film, or displaying the recorded radiation image information on a display device such as a CRT or the like.
The stimulable phosphor is a phosphor which, when exposed to an applied radiation, stores a part of the energy of the radiation, and, when subsequently exposed to applied stimulating rays such as visible light, emits light in proportion to the stored energy of the radiation. Usually, a sheet provided with a layer of the stimulable phosphor, or a stimulable phosphor sheet, is stored in a cassette, or a plurality of such stimulable phosphor sheets are stored in a magazine.
The above known system includes an image information reading apparatus which comprises a reading section for reading image information recorded on a stimulable phosphor sheet, and an erasing section for erasing remaining image information from the stimulable phosphor sheet after the recorded image information has been read. In the image information reading apparatus, after a cassette or a magazine (hereinafter referred to as a “cassettes”) housing a stimulable phosphor sheet which bears radiation image information of a subject recorded by an external exposure device is inserted into a loading section, the lid of the cassette is opened, and then the stimulable phosphor sheet is taken out of the cassette by a sheet feeding mechanism.
The stimulable phosphor sheet is thereafter delivered to the reading section by a sheet delivering mechanism. In the reading section, a laser beam or the like is applied to the stimulable phosphor sheet to read the recorded image information from the stimulable phosphor sheet. Thereafter, remaining image information is erased from the stimulable phosphor sheet in the erasing section, after which the stimulable phosphor sheet is stored in the cassette from which it has been removed or another cassette in the loading section. The cassette which stores the stimulable phosphor sheet is then removed from the image information reading apparatus.
The loading section does not have a space large enough to allow the cassette to be fully opened because of limitations imposed by the small size of the image information reading apparatus. In the loading section, therefore, the cassette is opened by tilting the lid of the cassette through a predetermined angle. The sheet feeding mechanism moves suction cups along a path which is inclined obliquely downwardly toward the stimulable phosphor sheet in the cassette, causes the suction cups to attract the stimulable phosphor sheet, and then lifts the suction cups to remove the stimulable phosphor sheet from the cassette.
FIG. 21
of the accompanying drawings shows a suction cup
2
as it moves into a cassette which stores a sheet
3
. As shown in
FIG. 21
, when the suction cup
2
moves obliquely downwardly to a surface to be attracted to the sheet
3
as indicated by the arrow X, the leading edge of a skirt
4
of the suction cup
2
obliquely contacts the surface of the sheet
3
. Therefore, until the attraction by the suction cup
2
of the sheet
3
is completed, the skirt
4
slips against the surface of the sheet
3
. At this time, frictional resistance imposed on the skirt
4
by the sheet
3
tends to deform, e.g., roll, the leading edge of the skirt
4
, resulting in a failure to attract the sheet
3
with the suction cup
2
.
The above problem is not limited to the arrangement in which the suction cups move obliquely toward and away from the stimulable phosphor sheet. If the suction cups have skirts whose height is larger than the diameter of the suction cups, then the skirts tend to roll on the stimulable phosphor sheet even when the suction cups move perpendicularly toward and away from the stimulable phosphor sheet.
The above system also includes an image information reproducing apparatus for reproducing radiation image information recorded on a stimulable phosphor sheet on a photosensitive medium such as a photographic film. The image information reproducing apparatus has a magazine loading section for loading a magazine which stores a plurality of photosensitive mediums, and a sheet feeding mechanism for removing the photosensitive mediums, one by one, from the magazine that is loaded in the magazine loading section. The sheet feeding mechanism has suction cups which suffer the same problem with respect to the photosensitive mediums as the problem described above with respect to the suction cups and the stimulable phosphor sheets in the image information reading apparatus.
Attempts have heretofore been made to solve the above problem by making suction cups of a slippery material or roughening the attracting surfaces of suction cups to make them slippery. However, if the suction cups are made slippery, then the frictional resistance between the suction cups and the sheet becomes smaller than required. Specifically, when the slippery suction cups move while attracting the sheet, the sheet is liable to be positionally displaced relatively to the suction cups, or fall off the suction cups.
SUMMARY OF THE INVENTION
It is a major object of the present invention to provide a method of and an apparatus for feeding a sheet by smoothly and reliably attracting the sheet with suction cups while effectively preventing the suction cups from being deformed, with a relatively simple arrangement.
The above and other objects, features, and advantages of the present invention will become more apparent from the following description when taken in conjunction with the accompanying drawings in which preferred embodiments of the present invention are shown by way of illustrative example.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1
is a vertical cross-sectional view of an image information reading apparatus which incorporates therein a sheet feeding mechanism according to a first embodiment of the present invention;
FIG. 2
is a perspective view of the sheet feeding mechanism according to the first embodiment;
FIG. 3
is a perspective view of a sheet feeder, which includes the sheet feeding mechanism, of the image information reading apparatus shown in
FIG. 1
;
FIG. 4
is a side elevational view of the sheet feeding mechanism shown in
FIG. 2
;
FIG. 5
is a schematic diagram of a piping system of the sheet feeding mechanism shown in
FIG. 2
;
FIG. 6
is a side elevational view of a sheet delivering mechanism of the sheet feeder;
FIG. 7
is a schematic diagram of the piping system which is switched to discharge air from suction cups;
FIG. 8
is a cross-sectional view showing the position of parts to start feeding a stimulable phosphor sheet with suction cups in the sheet feeding mechanism shown in
FIG. 2
;
FIG. 9
is a cross-sectional view showing the suction cups as they have been moved and eject air in the sheet feeding mechanism shown in
FIG. 2
;
FIG. 10
is a cross-sectional view showing the suction cups as they attract the stimulable phosphor sheet in the sheet feeding mechanism shown in
FIG. 2
;
FIG. 11
is a cross-sectional view showing the suction cups as they feed the attracted stimulable phosphor sheet toward nip rollers in the sheet feeding mechanism shown in
FIG. 2
;
FIG. 12
is a schematic diagram of a piping system of the sheet feeding mechanism according to a second embodiment of the present invention;
FIG. 13
is a schematic diagram of a piping system of the sheet feeding mechanism according to a third embodiment of the present invention;
FIG. 14
is a perspective view of a sheet feeding mechanism according to a fourth embodiment of the present invention;
FIG. 15
is a perspective view of a suction cup of the sheet feeding mechanism according to the fourth embodiment;
FIG. 16
is a cross-sectional view of the suction cup shown in
FIG. 15
;
FIG. 17
is a cross-sectional view showing the suction cups as they move into a cassette in the sheet feeding mechanism shown in
FIG. 14
;
FIG. 18
is a cross-sectional view showing the suction cups as they have entered the cassette in the sheet feeding mechanism shown in
FIG. 14
;
FIG. 19
is a cross-sectional view showing the suction cups as they insert an attracted stimulable phosphor sheet between nip rollers;
FIG. 20
is a cross-sectional view of a modified suction cup; and
FIG. 21
is a cross-sectional view showing the manner in which a conventional suction cup attracts a sheet in a cassette.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
As shown in
FIG. 1
, an image information reading apparatus
12
has a touch panel
14
on an upper front face thereof which serves as a control console and a monitor. The image information reading apparatus
12
also has a cassette loading section
18
disposed below the touch panel
14
for loading a cassette
16
removably in a sheet removal position. The cassette loading section
18
includes a sheet feeder
20
having a sheet feeding mechanism
10
according to a first embodiment of the present invention. The image information reading apparatus
12
further includes an erasing section
24
and a reading section
26
which are connected to the sheet feeder
20
through a sheet delivery system
22
.
The sheet delivery system
22
has a plurality of pairs of nip rollers
28
spaced along a vertical delivery path. The erasing section
24
has a plurality of erasing light sources
30
disposed in a position on one side of the vertical delivery path.
The reading section
26
comprises an auxiliary scanning system
38
having first and second pairs of rollers
34
,
36
for delivering a stimulable phosphor sheet
32
from the cassette
16
in an auxiliary scanning direction indicated by the arrow A, an optical system
40
for applying a laser beam L as it is deflected in a main scanning direction (substantially perpendicular to the auxiliary scanning direction) to the stimulable phosphor sheet
32
as it is delivered in the auxiliary scanning direction, and a light guiding system
42
for photoelectrically reading light which is emitted from the stimulable phosphor sheet
32
upon exposure to the laser beam L.
The cassette
16
comprises a housing
44
for storing the stimulable phosphor sheet
32
therein, and a lid
48
mounted on the housing
44
for opening and closing an opening
46
defined in the housing
44
. The cassette loading section
18
has a lid opening/closing mechanism (not shown) for opening and closing the lid
48
.
As shown in
FIGS. 2 and 3
, the sheet feeding mechanism
10
comprises a pair of suction cups
50
a
,
50
b
movable into the cassette
16
in the cassette loading section
18
with the lid
48
being open, a displacing mechanism
54
for displacing the suction cups
50
a
,
50
b
between the cassette
16
and a sheet delivering mechanism
52
and bringing the stimulable phosphor sheet
32
in the cassette
16
to the sheet delivering mechanism
52
, and a piping system
58
connecting the suction cups
50
a
,
50
b
to a vacuum pump (vacuum source)
56
for causing the suction cups
50
a
,
50
b
to attract the stimulable phosphor sheet
32
in the cassette
16
, and for ejecting air from the suction cups
50
a
,
50
b
toward a surface to be attracted, which is the reverse surface of the sheet opposite to a recording surface, of the stimulable phosphor sheet
32
when the suction cups
50
a
,
50
b
are moved into the cassette
16
.
The sheet feeder
20
has a pair of vertical side plates
60
a
,
60
b
which are spaced apart from each other in the direction indicated by the arrow C that is transverse to the direction indicated by the arrow B in which the stimulable phosphor sheet
32
is removed from the cassette
16
by the suction cups
50
a
,
50
b
. The displacing mechanism
54
has a first motor
62
fixedly mounted on the side plate
60
a
and having a drive shaft
62
a
, a small-diameter pulley
64
attached to the drive shaft
62
a
, a large-diameter pulley
68
attached to an end of a drive shaft
66
, and an endless belt
70
trained around the small-diameter pulley
64
and the large-diameter pulley
68
.
The drive shaft
66
has opposite ends rotatably supported respectively by the side plates
60
a
,
60
b
. An arm
72
has an end fixed to the large-diameter pulley
68
and an opposite end to which an end of a link
74
is angularly movably coupled, as shown in
FIGS. 2 through 4
. The link
74
has an opposite end coupled to a first support shaft
76
. To the other end of the drive shaft
66
, there is fixed an end of another arm
72
whose opposite end is angularly movably coupled to an end of another link
74
. The other link
74
has an opposite end coupled to another first support shaft
76
.
Each of the side plates
60
a
,
60
b
has a pair of guide grooves
80
,
82
defined therein as a guiding means
78
for moving the suction cups
50
a
,
50
b
along a path which is inclined obliquely downwardly toward the surface to be attracted of the stimulable phosphor sheet
32
in the cassette
16
. The guide grooves
80
,
82
have respective shapes for moving the suction cups
50
a
,
50
b
along the path. On each of the side plates
60
a
,
60
b
, the first support shaft
76
is aligned with the guide groove
80
and fixed to a corner of a rectangular movable frame
84
, and a second support shaft
86
is aligned with the guide groove
82
and fixed to a diagonally opposite corner of the rectangular movable frame
84
. Specifically, the first support shaft
76
extends through the guide groove
80
and has opposite ends fixed respectively to the link
74
and the movable frame
84
, and the second support shaft
86
extends through the guide groove
82
and has an end fixed to the movable frame
84
. The first and second support shafts
76
,
86
have respective bearings
88
a
,
88
b
mounted thereon and inserted respectively in the guide grooves
80
,
82
.
The movable frames
84
on the respective side plates
60
a
,
60
b
support therebetween the suction cups
50
a
,
50
b
which are spaced apart from each other by a distance commensurate with the dimension, in the direction indicated by the arrow C, of a stimulable phosphor sheet
32
having a minimum size. All stimulable phosphor sheets
32
of different sizes which are handled by the sheet feeder
20
are positioned with respect to a reference position near the side plate
60
a
, for example.
As shown in
FIGS. 2 and 5
, the piping system
58
coupled to the suction cups
50
a
,
50
b
has a circulation passage
90
communicating with the suction cups
50
a
,
50
b
and an inlet port
56
a
and an outlet port
56
b
of a vacuum pump
56
, and first and second solenoid-operated directional control valves
92
a
,
92
b
connected to the circulation passage
90
for selectively connecting the suction cups
50
a
,
50
b
to the inlet port
56
a
of the vacuum pump
56
to cause the suction cups
50
a
,
50
b
to attract the stimulable phosphor sheet
32
, and connecting the suction cups
50
a
,
50
b
to the outlet port
56
b
of the vacuum pump
56
to eject air from the suction cups
50
a
,
50
b
toward the surface to be attracted of the stimulable phosphor sheet
32
.
The circulation passage
90
is connected to a pressure sensor (pressure detecting means)
94
connected to the circulation passage
90
somewhere between the suction cups
50
a
,
50
b
and the inlet port
56
a
of the vacuum pump
56
, e.g., between the first solenoid-operated directional control valve
92
a
and the suction cups
50
a
,
50
b
, for detecting a negative pressure or vacuum in the suction cups
50
a
,
50
b
. Each of the first and second solenoid-operated directional control valves
92
a
,
92
b
comprises a three-port valve.
As shown in
FIGS. 2
,
3
, and
6
, the sheet delivering mechanism
52
comprises a plurality of sets of nip rollers
96
,
98
,
100
, and a second motor
102
for rotating the nip rollers
96
,
98
,
100
in unison with each other. The second motor
102
has a drive shaft with a drive pulley
104
fixedly mounted thereon. An endless belt
106
is trained around the drive pulley
104
, tension rollers
108
a
,
108
b
, and driven pulleys (not shown) coaxially coupled to selected ones of the nip rollers
96
,
98
,
100
. As shown in
FIG. 2
, the nip rollers
96
include a plurality of rubber rollers
112
,
114
spaced at given intervals and each having a certain width in the direction indicated by the arrow C. The other nip rollers
98
,
100
are similar in structure to the nip rollers
96
. The nip rollers
98
include a roller having a relatively large diameter for guiding the stimulable phosphor sheet
32
to pass through the sheet delivering mechanism
52
.
Operation of the sheet feeding mechanism
10
of the above structure will be described below with respect to a sheet feeding method according to the present invention.
A stimulable phosphor sheet
32
with radiation image information of a subject such as a human body being recorded by an exposure device (not shown) is stored in the cassette
16
in a light-tight fashion, and the cassette
16
is then set in the cassette loading section
18
of the image information reading apparatus
12
. After being loaded in the cassette loading section
18
, the lid
48
of the cassette
16
is swung to a given angular position by the lid opening/closing mechanism in the cassette loading section
18
, opening the opening
46
of the cassette
16
.
Then, the displacing mechanism
54
is actuated to displace the suction cups
50
a
,
50
b
into the cassette
16
, and the suction cups
50
a
,
50
b
eject air toward the surface to be attracted to the stimulable phosphor sheet
32
stored in the cassette
16
. Specifically, the first motor
62
is energized to cause the small-diameter pulley
64
and the endless belt
70
to turn the large-diameter pulley
68
on the side plate
60
a
about its own axis in unison with the drive shaft
66
in one direction.
The arm
72
is fixed to the large-diameter pulley
68
on the side plate
60
a
, and the other arm
72
is fixed to the other large-diameter pulley
68
on the side plate
60
b
. Therefore, when the drive shaft
66
is turned about its own axis, the arms
72
are angularly moved about the drive shaft
66
. As described above, the first support shafts
76
are coupled to the distal ends of the arms
72
by the respective links
74
, and the first and second support shafts
76
,
86
are movably disposed in the respective guide grooves
80
,
82
in each of the side plates
60
a
,
60
b
by the respective bearings
88
a
,
88
b.
When the arms
72
are angularly moved, the first and second support shafts
76
,
86
move respectively along the guide grooves
80
,
82
. The movable frames
84
connected to the first and second support shafts
76
,
86
then move the suction cups
50
a
,
50
b
along the path which is inclined obliquely downwardly toward the surface to be attracted of the stimulable phosphor sheet
32
in the cassette
16
(see FIG.
8
).
In the piping system
58
, as shown in
FIG. 7
, the first and second solenoid-operated directional control valves
92
a
,
92
b
are actuated to vent the inlet port
56
a
of the vacuum pump
56
to the atmosphere and connect the outlet port
56
b
thereof to the suction cups
50
a
,
50
b
. When the vacuum pump
56
is actuated, the vacuum pump
56
draws ambient air through the inlet port
56
a
and discharges air through the outlet port
56
b
. The air from the outlet port
56
b
is ejected from the suction cups
50
a
,
50
b
toward the stimulable phosphor sheet
32
stored in the cassette
16
(see FIG.
9
).
When the suction cups
50
a
,
50
b
are guided by the guiding means
78
to a position where they will attract the stimulable phosphor sheet
32
, the first and second solenoid-operated directional control valves
92
a
,
92
b
are inactivated, connecting the inlet port
56
a
of the vacuum pump
56
to the suction cups
50
a
,
50
b
and venting the outlet port
56
b
thereof to the atmosphere, as shown in FIG.
5
. When the vacuum pump
56
is actuated, the suction cups
50
a
,
50
b
draw in air from between the suction cups
50
a
,
50
b
and the surface to be attracted of the stimulable phosphor sheet
32
, as shown in FIG.
10
.
Then, the suction cups
50
a
,
50
b
attract the surface of the stimulable phosphor sheet
32
. When the pressure sensor
94
detects a predetermined negative pressure or vacuum in the suction cups
50
a
,
50
b
, the first motor
62
is reversed to angularly move the arms
72
to displace the movable frames
84
and the suction cups
50
a
,
50
b
from the cassette
16
toward the sheet delivering mechanism
52
. The stimulable phosphor sheet
32
attracted by the suction cups
50
a
,
50
b
is now taken out of the cassette
16
through the opening
46
.
As the suction cups
50
a
,
50
b
are displaced away from the cassette
16
, the stimulable phosphor sheet
32
attracted thereby has its leading end gripped by the nip rollers
96
which are being rotated in the directions indicated by the arrows in
FIG. 11
at a predetermined speed by the second motor
102
. Substantially at the same time that the leading end of the stimulable phosphor sheet
32
is gripped by the nip rollers
96
, the suction cups
50
a
,
50
b
release the stimulable phosphor sheet
32
. The stimulable phosphor sheet
32
then travels continuously from the nip rollers
96
through the nip rollers
98
to the nip rollers
100
, and thereafter is delivered by the sheet delivery system
22
through the erasing section
24
to the reading section
26
.
In the reading section
26
, as shown in
FIG. 1
, the stimulable phosphor sheet
32
is delivered in the auxiliary scanning direction indicated by the arrow A by the auxiliary scanning system
38
, and at the same time, the recording of the stimulable phosphor sheet
32
is scanned in the main scanning direction by the laser beam L from the optical system
40
. Therefore, the radiation image information recorded on the stimulable phosphor sheet
32
is photoelectrically read by the light guiding system
42
.
After the recorded radiation image information is read from the stimulable phosphor sheet
32
by the reading section
26
, the stimulable phosphor sheet
32
is delivered back by the sheet delivery system
22
. While the stimulable phosphor sheet
32
is being delivered upwardly along the vertical delivery path by the sheet delivery system
22
, remaining radiation image information on the stimulable phosphor sheet
32
is erased by the erasing light sources
30
of the remaining section
24
. Thereafter, the stimulable phosphor sheet
32
is sent back into the cassette
16
by the sheet feeding mechanism
10
. When the cassette
16
is withdrawn from the cassette loading section
18
, the lid
48
is closed onto the housing
44
by the lid opening/closing mechanism in the cassette loading section
18
. The closed cassette
16
is now taken out of the image information reading apparatus
12
.
In the first embodiment, when the suction cups
50
a
,
50
b
are moved to the stimulable phosphor sheet
32
in the cassette
16
, air is ejected from the suction cups
50
a
,
50
b
toward the surface to be attracted of the stimulable phosphor sheet
32
(see FIG.
9
). Therefore, an air layer is developed between the attracting surfaces (skirts) of the suction cups
50
a
,
50
b
and the surface to be attracted of the stimulable phosphor sheet
32
, allowing the suction cups
50
a
,
50
b
to move smoothly to a desired position on the surface to be attracted of the stimulable phosphor sheet
32
without being subject to much frictional resistance.
Consequently, the suction cups
50
a
,
50
b
can quickly move to an accurate position on the stimulable phosphor sheet
32
, and hence can reliably attract the stimulable phosphor sheet
32
. Since any undesirable frictional resistance between the suction cups
50
a
,
50
b
and the stimulable phosphor sheet
32
is essentially eliminated, the suction cups
50
a
,
50
b
are prevented from being deformed and hence from failing to attract the stimulable phosphor sheet
32
, and the stimulable phosphor sheet
32
is prevented from being positionally displaced before being attracted by the suction cups
50
a
,
50
b.
The piping system
58
has only the first and second solenoid-operated directional control valves
92
a
,
92
b
, each comprising a three-port valve, connected respectively to the inlet and outlet ports
56
a
,
56
b
of the vacuum pump
56
. Accordingly, the piping system
58
is highly simple in structure and can be manufactured relatively inexpensively.
Because air is ejected from the suction cups
50
a
,
50
b
toward the surface to be attracted of the stimulable phosphor sheet
32
, dust particles deposited on the stimulable phosphor sheet
32
can be blown away by the ejected air. The surface to be attracted of the stimulable phosphor sheet
32
is thus made clean and smooth, and can reliably be attracted by the suction cups
50
a
,
50
b
. In addition, when the piping system
58
is switched to develop a vacuum in the suction cups
50
a
,
50
b
, since no dust particles are present on the stimulable phosphor sheet
32
, the piping system
58
does not draw undesirable dust particles, and hence is prevented from being clogged during operation.
Moreover, when the stimulable phosphor sheet
32
is transferred to the sheet delivering mechanism
52
after being attracted and removed from the cassette
16
by the suction cups
50
a
,
50
b
, the suction cups
50
a
,
50
b
can eject air to separate the stimulable phosphor sheet
32
reliably therefrom.
In the first embodiment, the suction cups
50
a
,
50
b
are arranged to move along the path which is inclined obliquely downwardly toward the surface to be attracted of the stimulable phosphor sheet
32
in the cassette
16
. However, even if the suction cups
50
a
,
50
b
move vertically downwardly toward the stimulable phosphor sheet
32
in the cassette
16
, the suction cups
50
a
,
50
b
are prevented from being unduly deformed because of air ejected therefrom.
The cassette loading section
18
for loading the cassette
16
which stores a single stimulable phosphor sheet
32
may be replaced with a magazine loading section for loading a magazine which stores a plurality of stimulable phosphor sheets or a plurality of photographic films.
FIG. 12
is a schematic diagram of a piping system
58
a
of the sheet feeding mechanism according to a second embodiment of the present invention. piping system
58
a
comprises a vacuum pump (vacuum source)
115
, a first passage
117
a
communicating with the suction cups
50
a
,
50
b
and the vacuum pump
115
, a pressure pump (pressurized air source)
116
, a second passage
117
b
communicating with the suction cups
50
a
,
50
b
and the pressure pump
116
. The first and second passages
117
a
,
117
b
are merged into a third passage
117
c
to communicate with the suction cups
50
a
,
50
b
. The first passage
117
a
or the second passage
117
b
is connected to a pressure sensor (pressure detecting means)
118
. The vacuum pump
115
and the pressure pump
116
have a mechanism for preventing back flow of air in OFF-state.
In the second embodiment as constructed above, when the suction cups
50
a
,
50
b
are moved to the stimulable phosphor sheet
32
, the pressure pump
116
is actuated (ON-state) for ejecting air toward the stimulable phosphor sheet
32
.
Further, when the suction cups
50
a
,
50
b
are moved to a position where they will attract the stimulable phosphor sheet
32
, the vacuum pump
115
is actuated (ON-state) and the pressure pump
116
is turned off (OFF-state) for attracting the stimulable phosphor sheet
32
. Accordingly, the same effect as the one in the first embodiment is achieved.
FIG. 13
is a schematic diagram of a piping system
58
b
of the sheet feeding mechanism according to a third embodiment of the present invention. Those parts of the piping system
58
b
which are identical to those of the piping system
58
a
according to the second embodiment are denoted by identical reference characters, and will not be described in detail below.
In the piping system
58
b
, first and second opening and closing valves
119
a
,
119
b
, which are solenoid-operated valves, are connected to the first and the second passages
117
a
,
117
b
, respectively. As shown in
FIG. 13
, when the vacuum pump
115
is actuated (ON-state), the first opening and closing valve
119
a
is opened and the second opening and closing valve
119
b
is closed. Therefore, air is prevented from flowing back to a side of the pressure pump
116
. Further, when the pressure pump
116
is actuated (ON-state), the first opening and closing valve
119
a
is closed and the second opening and closing valve
119
b
is opened.
FIG. 14
shows in perspective a sheet feeding mechanism
120
according to a fourth embodiment of the present invention. Those parts of the sheet feeding mechanism
120
which are identical to those of the sheet feeding mechanism
10
according to the first embodiment are denoted by identical reference characters, and will not be described in detail below.
As shown in
FIG. 14
, the sheet feeding mechanism
120
has a pair of suction cups
122
a
,
122
b
movable into the cassette
16
in the cassette loading section
18
with the lid
48
being open, and a displacing mechanism
54
for displacing the suction cups
122
a
,
122
b
between the cassette
16
and a sheet delivering mechanism
52
and bringing the stimulable phosphor sheet
32
in the cassette
16
to the sheet delivering mechanism
52
.
Each of the suction cups
122
a
,
122
b
is made of an elastomeric material such as ethylene-propylene rubber (EPDM), butadiene acrylonitrile rubber (NBR), or the like. As shown in
FIGS. 15 and 16
, each of the suction cups
122
a
,
122
b
comprises a base
124
communicating with a vacuum source (not shown), and a conical skirt
126
integral with the base
124
for attracting a surface
32
a
of a stimulable phosphor sheet
32
. The base
124
has a through hole
128
defined therein for connection to the vacuum source and communicating with a suction chamber
130
which is defined between the surface
32
a
of the stimulable phosphor sheet
32
and an inner surface of the skirt
126
.
The skirt
126
has an annular convex lip
132
of arcuate cross section on its free end for contacting the surface
32
a
of the stimulable phosphor sheet
32
. The skirt
126
is tapered from the base
124
toward the annular convex lip
132
. The annular convex lip
132
is curved away from the surface
32
a
of the stimulable phosphor sheet
32
. The free end of the skirt
126
also has an annular recess
134
defined therein and opening away from the annular convex lip
132
.
The sheet feeding mechanism
120
according to the fourth embodiment operates as follows: As shown in
FIG. 17
, the suction cups
122
a
,
122
b
.are moved by the displacing mechanism
54
along the path which is inclined obliquely downwardly toward the surface
32
a
to be attracted of the stimulable phosphor sheet
32
in the cassette
16
.
Then, as shown in
FIG. 18
, with the suction cups
122
a
,
122
b
attracting the surface
32
a
of the stimulable phosphor sheet
32
, the first motor
62
of the displacing mechanism
54
is reversed. The arms
72
are angularly moved to move the movable frames
84
and the suction cups
122
a
,
122
b
from the cassette
16
toward the sheet delivering mechanism
52
. The stimulable phosphor sheet
32
attracted by the suction cups
122
a
,
122
b
is now taken out of the cassette
16
through the opening
46
.
The leading end of the stimulable phosphor sheet
32
is then gripped by the rollers
96
of the sheet delivering mechanism
52
. At this time, the nip rollers
96
are being rotated in the directions indicated by the arrows in
FIG. 19
at a predetermined speed by the second motor
102
. Substantially at the same time that the leading end of the stimulable phosphor sheet
32
is gripped by the nip rollers
96
, the suction cups
122
a
,
122
b
release the stimulable phosphor sheet
32
.
According to the fourth embodiment, as shown in
FIGS. 15 and 16
, the free end of the skirt
126
of each of the suction cups
122
a
,
122
b
has the annular convex lip
132
of arcuate cross section. Therefore, when the suction cups
122
a
,
122
b
move obliquely downwardly toward the surface
32
a
of the stimulable phosphor sheet
32
and then the skirt
126
slides on the surface
32
a
of the stimulable phosphor sheet
32
, the free end of the skirt
126
is prevented from being rolled or deformed on the surface
32
a
by frictional engagement therewith because the lower curved surface of the annular convex lip
132
smoothly slides on the surface
32
a.
Consequently, no gap is created between the free end of the skirt
126
and the surface
32
a
. The suction chamber
130
defined between the surface
32
a
and the skirt
126
is effectively evacuated by the vacuum source through the hole
128
for thereby firmly and reliably attracting the stimulable phosphor sheet
32
.
Each of the suction cups
122
a
,
122
b
has the annular convex lip
132
on the free end of the skirt
126
, which is curved away from the surface
32
a
. Since the suction cups
122
a
,
122
b
are relatively simple in structure, the sheet feeding mechanism
120
is also relatively simple in structure, and hence can be manufactured relatively inexpensively.
In the fourth embodiment, as shown in
FIG. 16
, the annular recess
134
is defined in the free end of the skirt
126
and open away from the annular convex lip
132
.
FIG. 20
shows a modified suction cup including a skirt
126
having a free end which has an annular convex lip
132
for contacting the surface
32
a
of the stimulable phosphor sheet
32
and an annular solid portion
136
facing away from the annular convex lip
132
. The annular solid portion
136
is effective to reinforce the free end of the skirt
126
.
The suction cups
50
a
,
50
b
in the sheet feeding mechanism
10
according to the first, second, and third embodiments may be replaced with the suction cups
122
a
,
122
b.
The suction cups
122
a
,
122
b
thus incorporated in the sheet feeding mechanism
10
are capable of more smoothly and reliably attracting the stimulable phosphor sheet
32
and removing the stimulable phosphor sheet
32
from the cassette
16
.
According to the present invention, as described above, since the suction cups are moved to a sheet removal position for removing a sheet from the cassette and eject air toward a surface to be attracted of the sheet, an air layer is developed between the attracting surfaces of the suction cups and the surface to be attracted of the sheet. Since any undesirable frictional resistance between the suction cups and the sheet is essentially eliminated, the suction cups are prevented from being deformed, and the sheet is prevented from being positionally displaced before being attracted by the suction cups. Thus, the suction cups are capable of smoothly and reliably attracting the sheet and removing the sheet from the cassette.
Furthermore, each of the suction cups has a skirt which has on its free end an annular convex lip of arcuate cross section for contacting the surface to be attracted of the sheet. Because the annular convex lip can smoothly slide on the surface to be attracted of the sheet, the free end of the skirt is prevented from being rolled or deformed on the surface to be attracted of the sheet by frictional engagement therewith. As a result, the suction cups are capable of smoothly and reliably attracting the sheet without fail. In addition, the sheet feeding mechanism can effectively be simplified in structure.
Although certain preferred embodiments of the present invention have been shown and described in detail, it should be understood that various changes and modifications may be made therein without departing from the scope of the appended claims.
Claims
- 1. A method of feeding a sheet, comprising the steps of:placing at least one sheet in a sheet removal position; moving a suction cup to said sheet removal position; ejecting air from said suction cup toward a surface to be attracted to said sheet; evacuating said suction cup to cause said suction cup to attract the surface to be attracted to said sheet; and moving said suction cup which has attracted said sheet away from said sheet removal position.
- 2. The method according to claim 1, further comprising the step of:moving said suction cup to said sheet removal position along a path which is inclined obliquely downwardly toward the surface to be attracted of said sheet.
- 3. The method according to claim 1, further comprising the step of:ejecting air from said suction cup when said sheet attracted by said suction cup is transferred toward a sheet delivering mechanism.
- 4. An apparatus for feeding a sheet, comprising:a suction cup movable into and out of a receptacle which stores at least one sheet and is open in a loading section; a displacing mechanism for displacing said suction cup between a position in said receptacle and a sheet delivering mechanism to cause said suction cup to transfer said sheet from said receptacle to said sheet delivering mechanism; and a piping system for attracting said sheet with said suction cup, and for ejecting air from said suction cup toward a surface to be attracted to said sheet when said suction cup is moved into said receptacle.
- 5. The apparatus according to claim 4, wherein said piping system comprises:a vacuum source; a circulation passage communicating with said suction cup and an inlet port and an outlet port of said vacuum source; and a pair of directional control valves connected to said circulation passage for selectively connecting said suction cup to said inlet port of the vacuum source to cause said suction cup to attract the sheet, and connecting said suction cup to said outlet port of the vacuum source to eject air from said suction cup toward the surface to be attracted to said sheet.
- 6. The apparatus according to claim 5, wherein said directional control valves comprise, respectively, a first solenoid-operated three-port valve connected to said inlet port of the vacuum source and a second solenoid-operated three-port valve connected to said outlet port of the vacuum source.
- 7. The apparatus according to claim 5, wherein said piping system further comprises:pressure detecting means connected to said circulation passage between said suction cup and said inlet port of the vacuum source.
- 8. The apparatus according to claim 4, wherein said piping system comprises:a vacuum source; a first passage communicating with said suction cup and said vacuum source; a pressurized air source; and a second passage communicating with said suction cup and said pressurized air source.
- 9. The apparatus according to claim 8, wherein said first passage or said second passage is connected to a pressure detecting means.
- 10. The apparatus according to claim 8, wherein first and second opening and closing valves are connected to said first and said second passages, respectively.
- 11. The apparatus according to claim 9, wherein first and second opening and closing valves are connected to said first and said second passages, respectively.
- 12. The apparatus according to claim 4, wherein said displacing mechanism comprises guiding means for moving said suction cup along a path which is inclined obliquely downwardly toward the surface to be attracted of said sheet in said receptacle.
- 13. The apparatus according to claim 4, wherein said receptacle comprises a cassette for storing said sheet.
- 14. The apparatus according to claim 4, wherein said suction cup has a skirt for attracting said sheet, said skirt having on a free end thereof an annular convex lip of arcuate cross section for contacting the surface to be attracted to said sheet.
- 15. The apparatus according to claim 14, wherein said annular convex lip is curved away from the surface to be attracted to said sheet.
- 16. An apparatus for feeding a sheet, comprising:a suction cup movable into and out of a receptacle which stores at least one sheet and is open in a loading section; and a displacing mechanism for displacing said suction cup between a position in said receptacle and a sheet delivering mechanism to cause said suction cup to transfer said sheet from said receptacle to said sheet delivering mechanism; said suction cup having a skirt for attracting said sheet, said skirt having on a free end thereof an annular convex lip of arcuate cross section having a bottom portion for contacting a surface of said sheet, said annular lip being curved away from the surface to be contacted, so as to form an annular recess which faces away from the surface to be contacted.
- 17. The apparatus according to claim 16, wherein said skirt has on the free end thereof an annular solid portion facing away from said annular convex lip.
- 18. The apparatus according to claim 16, wherein said displacing mechanism comprises guiding means for moving said suction cup along a path which is inclined obliquely downwardly toward the surface to be attracted the said sheet in said receptacle.
- 19. The apparatus according to claim 16, wherein only said annular convex lip of arcuate cross section of the suction cup is in contact with the stimulable phosphor sheet when the suction cup is moved on the surface to be attracted to the stimulable phosphor sheet.
- 20. The apparatus according to claim 16, wherein a main portion of said skirt, which extends to said annular recess, is smooth.
Priority Claims (2)
Number |
Date |
Country |
Kind |
10-073990 |
Mar 1998 |
JP |
|
10-082020 |
Mar 1998 |
JP |
|
US Referenced Citations (13)