Photographing device and X-ray photographing system utilizing the same

A photographing device is provided with a pair of support members positioned in mutually opposed manner across a film, a sensitivity increasing screen mounted on at least one of the paired support members, a sealing member for hermetically sealing a space containing the film and the sensitivity increasing screen, a vacuum pump for reducing the pressure in the sealed space to maintain the film and the sensitivity increasing screen in mutual close contact, and a support member for maintaining the film in a predetermined position between the support member in the sealed space. Thus the sensitizing screen can be securely contacted with the film, and errors in operation are reduced even when the photographing operation is conducted with the film in vertical or inclined position.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a device composed of a pair of support 
members, on at least one of which a sensitizing screen is mounted, said 
support members being positioned opposed to a photographing stage and 
supporting therebetween a photographing film, for X-ray photographing 
thereon. 
2. Related Background Art 
In an X-ray photographing apparatus for X-ray photographing for example the 
chest of a patient, in order to support an X-ray film in a photographing 
stage, there has conventionally been proposed a mechanism for maintaining 
the X-ray film in close contact with a sensitizing screen by mechanically 
pressing a rear support member toward a front support member with 
satisfactory transmittance to the X-ray. In such method, however, 
satisfactory contact is difficult to attain because of the deformation of 
the support members by the pressing force, so that it is necessary to 
provide particular structure in the support members, and to regulate the 
pressing force in different portions of the entire plane. Also the front 
support member has to have a high regidity and a satisfactory 
transmittance to the X-ray, and has therefore to be made with an expensive 
material difficult to work, such as CFRP plate. 
Because of these drawbacks there is also known so-called vacuum contact 
method in which the front or rear sensitizing screen is mounted on an 
elastic member such as rubber which is in turn mounted on a frame-shaped 
rigid support member, and the space surrounded by the front and rear 
sensitizing screens is sealed by suitable means such as a packing and is 
reduced in pressure by a vacuum pump connected thereto, whereby the 
elastic support member is pressed by the atmospheric pressure toward the 
other support member, thus achieving close contact. Such a method is for 
example disclosed in the Japanese Utility Model Publication No. 53-16291. 
As the film is placed horizontally in such a device, it is not displaced 
from the predetermined position within a period from the film feeding with 
rollers to said position to the replacement of a cover. However, if this 
vacuum contact method is employed in a photographing apparatus in which 
the film is vertically supported, the film will drop by gravity in a 
period from the separation of rollers to the replacement of the cover and 
the pressure reduction of the interior. 
Also in such a vacuum contact method, in case of photographing with the 
film in a nonhorizontal position, a notch is required as disclosed in the 
Japanese Utility Model Publication No. 60-4178 for loading, unloading and 
supporting the film, but the presence of such a notch enhances the air 
leakage, thus requiring a larger capacity in the vacuum means such as a 
vacuum pump. 
SUMMARY OF THE INVENTION 
The object of the present invention is to provide an X-ray photographing 
device capable of achieving vacuum sealing over the entire area, also 
ensuring secure contact of the sensitizing screen to the film even with 
vacuum means such as a vacuum pump of a limited capacity, and providing 
few errors in the photographing operation with the film in vertical or 
inclined position, and a photographing system employing said X-ray 
photographing device.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
In the following there will be explained in detail embodiments of an 
apparatus for X-ray photographing of the chest of a person, with reference 
to the attached drawings. 
FIG. 12 schematically shows an X-ray photographing system, for X-ray 
photographing of the chest of a person to be inspected, wherein shown are 
an X-ray tube 101; a person 102 to be inspected; an X-ray photographing 
device 103; and a support 104 therefor. FIG. 13 is an external view of the 
X-ray photographing device 103 shown in FIG. 12, wherein 105 and 106 are 
supply magazines containing unexposed X-ray films of different sizes, and 
107 indicates a receiving magazine containing an exposed film. 108 is a 
chest plate to which the chest of the person to be inspected is to be 
maintained in contact. Inside said chest plate there is provided a 
photographing stage for setting a film, and the X-ray irradiation is made 
while an X-ray film is supported on said stage whereby the X-ray image of 
the chest of said person is recorded on said film. 
The internal structure of the X-ray photographing device shown in FIG. 13 
will be explained in more details, with reference to other drawings. FIG. 
1 is a perspective view of the structure principally of said stage; FIG. 2 
is a front view of said interior seen from a direction A shown in FIG. 1; 
FIG. 3 is a rear view of said interior seen from a direction B shown in 
FIG. 1; FIGS. 4 and 5 are lateral views; and FIGS. 6 to 9 are views 
showing the function. 
A front support member 1 is made of a material of a satisfactory X-ray 
transmittance, and a front sensitizing screen 2 is adhered thereto. A rear 
support member 3 is made of an elastic and extendable material such as 
rubber, and is mounted for example by adhesion on a frame member 4 of 
higher rigidity. A rear sensitizing screen 5 is mounted for example by 
adhesion on the rear support member 3. The sensitizing screens need not 
necessarily be present front and rear, but the photographing is possible 
if at least a screen is provided on either side. A hermetic flexible 
packing 6 is mounted, for example by adhesion, on the frame member 4, 
either directly or by way of the rear support member 3. The rear 
sensitizing screen 5 is rendered movable front and back to a certain 
extent, by the elasticity of the rear support member 3. At left and right 
in the internal upper part of the frame member 4, there are provided 
protruding portions 7, 8 as shown in FIG. 2. In said protruding portions 
7, 8 there are respectively provided recesses 9, 10, in which rollers 11, 
12 are respectively supported rotatably on horizontal shafts 13, 14. As 
shown in FIG. 4, these rollers 11, 12 slightly protrude from the front 
face of the frame member 4. Also on the protruding portions 7, 8 there are 
mounted, for example by adhesion, annular suction members 15, 16 made of a 
flexible material such as rubber. These suction members 15, 16 have a 
height, when seen from the side, slightly lower than the protruding height 
of the rollers 11, 12, and serve to support the film by suction. These 
suction members 15, 16 and the rollers 11, 12 are so positioned as to be 
inside two apertures 22, 23 provided on the rear support member 3. 
As shown in FIG. 2, the suction members 15, 16 have, at the centers 
thereof, exhaust holes 17, 18 which also penetrate the protruding portions 
7, 8. As shown in FIG. 3, the frame member 4 is provided, on the rear side 
thereof, with projections 19, 20 having holes communicating with the 
exhaust holes 17, 18, and a branched air hose 21 is connected to said 
projections 19, 20. At the other end of the air hose 21 there are 
connected a control valve 35, and, through an air hose 36, a vacuum pump 
37. The film is supported by suction, by reducing pressure inside said 
suction members 15, 16. 
On the other hand, in the lower part of the frame member 4, there are 
provided an exhaust hole 24 penetrating through the rear support member 3 
and the frame member 4, and a projection 25 having a hole communicating 
with said exhaust hole 24. On said projection 25 mounted is an air hose 
26, of which the other end is connected to a control valve 38 and, through 
an air hose 39, a vacuum pump 40 which serves to reduce the pressure in a 
sealed space including the X-ray film and the sensitizing screens. 
In the following the pressure reducing means including the vacuum pump 40 
and the control valve 38 will be called the first vacuum means, and that 
including the vacuum pump 37 and the control valve 35 will be called the 
second vacuum means. The level of vacuum of the support means created by 
the second vacuum means is selected stronger than that in the sealed space 
created by the first vacuum means. 
Referring to FIG. 4, the front support member 1 is fixed on an 
unrepresented frame, while the frame member 4 is rotatably supported by 
said frame and can rotate in a direction C in FIG. 4 by unrepresented 
drive means thereby contacting or separating the front and rear support 
members. Above the front support member 1, a roller 27 is rotatably 
supported by said frame. A lever 28 is rotatably supported by a fixed 
shaft 29, then a lever 30 is articulated to said lever 28 by way of a 
shaft 31, and a roller 32 is rotatably supported by a shaft 33 mounted on 
the end of the lever 30. Rotation of the lever 28 about the fixed shaft 29 
allows the roller 32 to move between positions shown in FIGS. 6 and 7, by 
means of unrepresented guide means. The roller 32 is constantly biased in 
a direction D shown in FIG. 6 or 7, by unrepresented biasing means, either 
in the position in FIG. 6 or 7 or during the movement, and is rotated in 
the state shown in FIG. 6 or 7 or during the movement. Said levers 28, 30 
and rollers 27, 32 are provided on each lateral side of the film, but the 
rollers 27, 32 may be extended over the entire width of the film. Below 
the roller 32 there is provided, as shown in FIG. 4, a movable guide plate 
34, which can be moved between solid-lined and broken-lined positions. 
In the following there will be explained the function of the 
above-explained structure. A film is taken out by an unrepresented feeding 
mechanism from stacked plural films in the supply magazine. The film F 
thus taken out is pinched between the rollers 27, 32 and fed from above as 
shown in FIGS. 4 and 6, and inserted between the sensitizing screens 2 and 
5. Immediatedly before the rear end of the film F leaves the rollers 27, 
32, the roller 32 is stopped, the lever 28 is rotated clockwise, and the 
roller 32 is rotated again in such a manner that the peripheral speed 
thereof becomes equal to the moving speed thereof, whereby the roller 
rolls on the film substantially without slippage. When the roller 32 
reaches the position shown in FIG. 7, it is rotated counterclockwise and 
it is stopped at a position where the upper ends of the film F and the 
sensitizing screens substantially meet. 
Then the film F is sucked by the second vacuum means. More specifically, 
the vacuum pump 37 is activated to generate, in the exhaust holes 17, 18, 
a reduced pressure determined by the control valve 35 through the air 
hoses 36, 21 whereby the film F is sucked to the suction members 15, 16. 
Then the lever 28 is rotated counterclockwise and the roller 32 is rotated 
counterclockwise in such a manner that the peripheral speed thereof is 
equal to the moving speed thereof, whereby said roller 32 is elevated by 
rolling on the film F and the guide plate 34 without slippage. Rotation of 
the lever 28 and the roller 32 is terminated when the roller 32 returns to 
the initial position. 
When the guide plate 34 is elevated to the broken-lined position in FIG. 4, 
and the frame member 4 is advanced by rotation whereby the front support 
member 1 and the frame member 4 are mutually closed as shown in FIGS. 5 
and 8. During these operations, the film F is supported by suction by the 
suction members 15, 16. In the closed state shown in FIGS. 5 and 8, the 
rear and front sensitizing screens 5 and 2 are not mutually contacted but 
have a small gap d therebetween, but a space (hereinafter called space 
.alpha.) surrounded and sealed by the front support member 1, rear support 
member 3, frame member 4 and packing 6 is in a hermetically sealed state. 
In this state, the pressure of said space a is reduced by the first vacuum 
means. More specifically, the vacuum pump 40 is activated to suck the 
internal air through the air hoses 39, 26 and the exhaust hole 24, thereby 
bringing the space a to a reduced pressure determined by the control valve 
38. Because of its elasticity, the rear support member 3 is movable front 
and back at the aperture of the frame member 4 and moves forward together 
with the rear sensitizing screen 5 by being pushed by the atmospheric 
pressure, whereby the film F is brought into close contact with the front 
and rear sensitizing screens 2, 5 as shown in FIG. 9. For example, if the 
internal pressure of the space .alpha. is made lower by 0.2 atm. than the 
atmospheric pressure, a pressing force of 0.2 kgf/cm.sup.2 will be 
exerted. 
If the reduced pressure of the space a created by the first vacuum means is 
made equal to the reduced pressure created by the second vacuum means for 
sucking the film F, the suction members 15, 16 will lose the power to 
support the film F as the pressure in the space .alpha. is reduced. If 
even a slight air layer is formed between the suction members 15, 16 and 
the film F, the film F may drop when the space .alpha. is opened to the 
atmospheric pressure after the X-ray photographing. In the present 
embodiment, therefore, the vacuum level of the second vacuum means is 
selected larger than that of the first vacuum means, whereby the film F is 
securely supported by the suction members 15, 16 even when the pressure of 
the space .alpha. is reduced. 
After the film is set in the photographing stage as explained above, the 
X-ray photographing of the chest of the person to be inspected is 
conducted by the system shown in FIG. 12. After said photographing, the 
first vacuum means is deactivated and the space .alpha. is opened to the 
atmospheric pressure, whereby a gap is again formed between the front and 
rear sensitizing screens 2, 5 by the returning force of the rear support 
member 3. In this state the second vacuum means is still active. Then the 
frame member 4 moves backward with counterclockwise rotation to return the 
state shown in FIGS. 4 and 7. Subsequently the guide plate 34 moves to the 
solid-lined position in FIG. 4, and the roller 32 moves to the position in 
FIG. 7, by rolling without slippage as explained before. Then the second 
vacuum means is deactivated and the exhaust holes 17, 18 are opened to the 
atmospheric pressure, whereby the suction force is lost and the film F 
leaves from the suction members 15, 16. Thus, when the reduced pressure in 
the space .alpha. is released, the film F released from the sensitizing 
screens is prevented from dropping by the gravity, as it is still 
supported by the support means. 
Then the roller 32 is rotated clockwise, and is stopped when the leading 
end of the film F reaches a position slightly above the roller 27. 
Subsequently the roller 32 is moved to a position in FIG. 6 by rolling 
without slippage as explained before, and the rotation of the lever 28 is 
terminated and the roller 32 is rotated clockwise to advance the film F 
from between the sensitizing screens 2, 5. Thus advanced exposed film F is 
accommodated in the receiving magazine by an unrepresented transport 
mechanism. 
In the above-explained embodiment, the control valves 35, 38 are provided 
for obtaining different vacuum levels in the support members 15, 16 and in 
the space .alpha., but said control valves may be dispensed with if the 
vacuum level created by the pump 37 is larger than that created by the 
pump 40. Also even in case the vacuum levels of said pumps 37, 40 are 
same, a similar effect can be obtained by dispensing with the control 
valve 35 for film supporting and controlling the vacuum level with the 
control valve 38. In any case the pressure for supporting the film F 
should be selected lower than that in the space .alpha.. 
In the above-explained embodiment, the packing 5 is fixed on the frame 
member 4, but it may be fixed on the front support member 1. Also instead 
of driving the roller 32, it is possible to constructe the roller 32 as an 
idler roller and to drive the rollers 27, 11, 12. For driving the rollers 
11, 12, a small motor may be provided in the frame member 4 so as not to 
deteriorate the hermeticity. Otherwise the frame member 4 may be provided 
with an open/closable cover, which is closed to maintain the hermeticity 
when the frame member 4 is closed, but is opened for inserting drive 
transmission means in case of driving said rollers 11, 12. 
As explained in the foregoing, the present embodiment securely achieves 
close contact of sensitizing screens to the film even with a limited 
capacity in the vacuum means such as vacuum pump, since the sealing by the 
frame members is obtained over the entire area. Also a high reliability 
without errors in operation can be obtained as the sucking force to the 
film is made stronger than the vacuum in the sealed space. 
FIGS. 10 and 11 illustrate a variation of the support means for the film. 
This embodiment is featured by supporting the film with pressing levers in 
the sealed space, instead of suction support of the film with the suction 
members. The frame member 4 is provided with an oblong groove 50, 
accommodating a lever 42 rotatable about a shaft 41. At the end of said 
lever 42 there is provided a projecting part 43 for pressing and 
supporting an end portion of the film. The projecting part is configured 
so as not interfere with the roller 32 when the roller descends. The lever 
42 is biased toward the frame member 4 by unrepresented biasing means. At 
the rear side of the groove 50 there is provided a thin stretchable rubber 
film 40' in order to prevent air leakage from the groove 50. Behind the 
frame member 4 there is provided a pushing member 44 which can be moved to 
or from the frame member 4 and is adapted, when moved thereto, to push up 
the lever 42 across said rubber film 40'. FIG. 10 shows a state where the 
lever 42 is pushed up. A similar structure is provided at the other side 
of the film, namely at the side of the roller 12, so that the film is 
supported in both end portions outside the image area. 
In the above-explained structure, when the film F is brought into a 
predetermined position by a transport mechanism similar to that in the 
foregoing embodiment, the pushing member 44 is retracted, whereby the 
lever 42, which is initially pushed up as shown in FIG. 10, is biased to 
the frame member 4 as shown in FIG. 11, thereby supporting the film F by 
pressing an area outside the image area by means of the projecting portion 
of the lever 42. Then the roller 32 is elevated, and the frame member 4 is 
advanced to form a sealed space .alpha.. Subsequently the pressure in said 
space .alpha. is reduced by the vacuum means to maintain the film F in 
close contact between the sensitizing screens, and the photographing 
operation is conducted in this state. Subsequently the reduced pressure is 
released to cancel the close contact state, then the frame member 4 is 
retracted with descent of the roller 32, and the pushing member 44 is 
advanced to push up the lever 42. In this state the roller 32 is rotated 
clockwise to move the film F upwards, thereby transporting said film F 
from the photographing stage. 
The present embodiment also has the advantages of secure close contact 
between the film and the sensitizing screens because of the sealing over 
the entire area by the frame members, and reduced errors in operations as 
the film is securely supported by the pressing levers. 
In the foregoing embodiments, the film F is continuously supported by the 
support means from before the photographing operation to after said 
operation, for achieving securer and simpler operations, but such film 
supporting during the photographing operation is not indispensable, as 
long as the film is securely supported at least when the reduced pressure 
in the space .alpha. is released after said photographing operation.