Sheet feeding or delivering – Feeding – By means to convey sheet
Reexamination Certificate
2001-11-16
2004-01-27
Mackey, Patrick (Department: 3651)
Sheet feeding or delivering
Feeding
By means to convey sheet
C271S272000, C271S010120, C271S243000, C271S245000, C399S395000
Reexamination Certificate
active
06682069
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a sheet conveyor system which conveys a plurality of kinds of sheet material different in width, and more particularly to such a sheet conveyor system which can convey straight the sheet to be conveyed irrespective of width.
2. Description of the Related Art
Recently, there has been put into practice a system in which a radiation image of an object such as a human body is once stored on a stimulable phosphor sheet (or a radiation image conversion panel) by exposing the stimulable phosphor sheet to radiation through the object to have the stimulable phosphor sheet store radiation energy, and stimulated emission which is emitted from each part of the stimulable phosphor sheet upon exposure to stimulating light in proportion to the radiation energy stored thereon is photoelectrically read, thereby obtaining a digital image signal representing the radiation image stored on the stimulable phosphor sheet, and the digital image signal is reproduced as a visible image on a recording medium such as a photographic film or on an image display system such as those using a CRT.
In such a system, the stimulable phosphor sheets are handled with each contained in one cassette or with the sheets contained in one magazine by two or more.
In the system, there is generally employed a radiation image information read-out apparatus provided with a read-out section for reading out a radiation image stored in stimulable phosphor sheets and an erasing section for exposing the stimulable phosphor sheet to erasing light after the image signal is obtained from the stimulable phosphor sheet so that the residual energy of the radiation is fully released from the stimulable phosphor sheet. In the radiation image information read-out apparatus, stimulable phosphor sheets on which radiation images of objects have been recorded by external radiation image recording apparatus are loaded with each stimulable phosphor sheet contained in a cassette or with the sheets contained in magazines by two or more. (The cassettes and the magazines will be referred to as a “container”, hereinbelow.) Then the lid of the container is opened and a sheet conveyor system takes out the stimulable phosphor sheets from the container one by one and conveys the stimulable phosphor sheet to the read-out section.
The read-out section reads a radiation image recorded on the stimulable phosphor sheet. After read-out, the stimulable phosphor sheet is transferred to the erasing section and the residual energy of the radiation is fully released from the stimulable phosphor sheet. Thereafter, the renewed stimulable phosphor sheet is returned to the original container or put in another container and removed from the radiation image information read-out apparatus together with the container.
Further, the aforesaid system is provided with an image reproducing system for reproducing a radiation image on a photosensitive material such as a photographic film. In the image reproducing system, a plurality of sheets of photosensitive material are taken out from a magazine one sheet by one sheet by a suction mechanism and transferred to a sheet conveyor system, which conveys the photosensitive material sheet to a recording system. The recording system records a radiation image on the photosensitive material sheet, for instance, by exposing the sheet to a laser beam on the basis of an image signal obtained from the stimulable phosphor sheet.
The stimulable phosphor sheet and the photographic film (such sheets will be simply referred to as a “sheet”, hereinbelow) are in various sizes by purpose. Accordingly, the sheet conveyor system generally conveys the sheet with one side edge of the sheet kept in a reference position.
FIG. 10
shows an example of the conventional sheet conveyor system. As shown in
FIG. 10
, the conventional sheet conveyor system has a roller pair
103
, one of which is a drive roller
101
which is driven by, for instance, an electric motor (not shown) and the other of which is a nip roller
102
which is positioned above the drive roller
101
and is associated with the drive roller
101
to nip therebetween a sheet
140
to be conveyed. The drive roller
101
comprises a shaft
111
and three roller portions
112
A,
112
B and
112
C which are of rubber and mounted on the shaft
111
at predetermined intervals. Similarly the nip roller
102
comprises a shaft
121
and three roller portions
122
A,
122
B and
122
C which are of rubber and mounted on the shaft
121
at predetermined intervals. The nip roller
102
is pressed against the drive roller
101
by compression springs
127
a
and
127
b
by way of bearings
125
a
and
125
b
disposed on opposite ends thereof. When the drive roller
101
is driven, the sheet
140
is conveyed nipped between the drive roller
101
and the nip roller
102
with one side edge
140
a
of the sheet
140
held in a reference position
105
irrespective of the width of the sheet
140
. That is, when the width of the sheet
140
is small, the sheet
140
is conveyed nipped between the roller portions
112
A and
122
A and
112
B and
122
B at its opposite edge portions. When the width of the sheet
140
is large, the sheet
140
is conveyed nipped between the roller portions
112
A and
122
A,
112
B and
122
B and
112
C and
122
C at its opposite edge portions and an intermediate portion.
Setting of force of the springs
127
a
and
127
b
will be described, hereinbelow. When a large size sheet
140
is to be conveyed as shown in
FIG. 11
, the conveying force is maximized at the outer side of the roller portions
112
A and
122
A and at the outer side of the roller portions
112
C and
122
C. Accordingly when the nipping force f
1
acting at the outer side of the roller portions
112
A and
122
A is equal to the nipping force f
2
acting at the outer side of the roller portions
112
C and
122
C, the sheet
140
can be conveyed straight. The nipping force f
1
acting at the outer side of the roller portions
112
A and
122
A can be made equal to the nipping force f
2
acting at the outer side of the roller portions
112
C and
122
C, when the force F
1
of the compression spring
127
a
is set equal to the force F
2
of the compression spring
127
b.
To the contrast, when a small size sheet
140
is to be conveyed, the sheet
140
is nipped only between the roller portions
112
A and
122
A and between the roller portions
112
B and
122
B and as a result the roller portions
112
C and
122
C are spaced from each other as shown in FIG.
10
. When a space is formed between the roller portions
112
C and
122
C while the opposite ends of the nip roller are pressed against the drive roller
101
by the forces F
1
and F
2
of the compression springs
127
a
and
127
b
, a moment which tends to nullify the space acts on the nip roller
102
together with the gravity of the roller portion
122
C, which makes the nip roller
102
inclined in a direction in which the space is nullified. When the nip roller
102
is thus inclined, the nipping force acting between the roller portions
112
B and
122
B becomes stronger than that acting between the roller portions
112
A and
122
A and the portion of the sheet
140
between the roller portions
112
B and
122
B comes to be conveyed at a higher speed than the portion of the sheet
140
between the roller portions
112
A and
122
A, whereby the sheet
140
comes to be conveyed obliquely rightward as seen in FIG.
10
. Further, since the roller portions
112
B and
122
B are of rubber, the roller portions
112
B and
122
B are apt to collapse and accordingly, it is difficult to prevent production of a difference in conveying speed. In view of conveying straight small size sheets, the forces of the springs
127
a
and
127
b
should be set in the following manner.
When a small size sheet
140
is to be conveyed as shown in
FIG. 12
, the conveying force is maximized at the outer side of the roller portions
112
A and
122
A and at the outer side of the roller portions
112
B a
Fuji Photo Film Co. , Ltd.
Mackey Patrick
Sughrue & Mion, PLLC
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