TECHNICAL FIELD
The present invention relates to a reading apparatus of
transmission type film. More particularly, it relates to a reading
apparatus of transmission type film simplified in the laser optical
system.
BACKGROUND ART
Hitherto, in a reading apparatus of transmission type film for
medical use (hereinafter called reading apparatus), as shown in Fig. 18,
a laser beam c emitted from a semiconductor laser device a and focused
by a focusing lens b is reflected by a polygonal mirror d, and a film f
surface held in a flat plane is scanned (main scanning). In this case,
to correct the optical path length, an F-Θ lens g is interposed between
the polygonal mirror d and film f, and to correct plane tilting,
moreover, a cylindrical lens h is disposed after the F-Θ lens g. After
main scanning, the film f is conveyed, for example, downward while the
deflection in the main scanning direction of the film f is being
suppressed by a pair of cylindrical driving rollers i, i and a pair of
cylindrical driven rollers j, j as shown in Fig. 19. This is sub-scanning
of film f. Alternatively, it is designed to drive by using a
set of combination of driving roller i and driven roller j as shown in
Fig. 20. In Fig. 20, reference code k denotes a scanning unit on which
an optical system such as polygonal mirror d is mounted. In such
constitution, the sub-scanning mechanism of film f is simplified by
using cylindrical rollers i, j, but, to the contrary, the optical
characteristic depends on the F-Θ lens g, and the F-Θ lens g is
expensive, and the cost of the reading apparatus is raised.
To solve these problems of the reading apparatus composed by
using the F-Θ lens g, as shown in Fig. 21, a reading apparatus is
proposed to compose a film conveying mechanism, in which the film f
surface is an arc surface along the main scanning direction, and sub-scanning
is realized by combination of barrel roller m and drum roller
n. However, when the film f is conveyed by such conveying mechanism,
although deflection in main scanning direction of the film f is
suppressed, sub-scanning is not smooth because the peripheral speed
differs between the central part and circumferential part of the rollers
m, n.
It is hence an object of the invention to solve the problems of
the prior art, and to present a reading apparatus of transmission type
film capable of reading the film precisely without using F-Θ lens g.
DISCLOSURE OF THE INVENTION
It is a first aspect of the invention to present a reading
apparatus of transmission type film comprising a film conveying means
for conveying a film on an arc surface similar to a free deflection
curve of film.
The first aspect of the invention, more specifically, relates to
a reading apparatus of transmission type film comprising a film holding
means having an arc surface similar to a free deflection curve of film,
and a film conveying means having a driving roller disposed beneath the
arc surface, a driven roller disposed above the arc surface
corresponding to the driving roller, for bringing the driving member of
the driving roller into contact with the film back side and the driven
member of the driven roller into contact with the film face side.
Preferably, in the first aspect of the invention, the driving
member of the driving roller is a pair of driving wheels disposed at a
specific interval on a drive shaft, and the driven member of the driven
roller is a pair of driven wheels mounted on a shaft member
corresponding to the driving wheels.
Preferably, in the first aspect of the invention, the abutting
surface of the driving wheels and driven wheels with the film is an arc
surface.
Preferably, in the first aspect of the invention, the driven
roller is free to ascend and descend.
Preferably, the first aspect of the invention further comprises
a box-shaped main body composed of parallel ceiling member and bottom
member having the longitudinal direction in the scanning direction of
laser beam constituted by combining flat members, a pair of photo
detecting means disposed at proper positions on planes parallel to the
scanning plane of laser beam of the main body, and a focusing device for
film density detector forming a ceiling member contacting with the back
side of a shell member on which the film of the box-shaped main body is
mounted and conveyed, along the back side of the shell member, and
forming a slit along the scanning direction of the laser beam for moving
the laser beam forward into the main body in this ceiling member.
Herein, the slit is covered, for example, with a scattering film
for scattering the light appropriately, and a coating is formed inside
of the box-shaped main body for preventing absorption of laser beam
getting into the main body.
Preferably, the first aspect of the invention further comprises
film width aligning means.
Herein, the width aligning means has a width aligning member
free to move back and forth in the film width direction disposed
oppositely.
It is a second aspect of the invention to present a film
conveying device used in a reading apparatus of transmission type film,
for conveying a film on an arc surface similar to a free deflection
curve of film.
More specifically, the film conveying device in the second
aspect of the invention comprises film holding means having an arc
surface similar to a free deflection curve of film, a driving roller
disposed beneath the arc surface, and a driven roller disposed above the
arc surface corresponding to the driving roller, in which the driving
member of the driving roller contacts with the film back side, and the
driven member of the driving roller contacts with the film face side.
In the second aspect of the invention, two sets of combination
of driving roller and driven roller are used, and each set is disposed
oppositely across the main scanning surface.
Preferably, in the second aspect of the invention, the driving
member of the driving roller is a pair of driving wheels disposed at a
specific interval on a drive shaft, and the driven member of the driven
roller is a pair of driven wheels mounted on a shaft member
corresponding to the driving wheels.
Preferably, in the second aspect of the invention, the abutting
surface of the driving wheels and driven wheels with the film is an arc
surface.
Preferably, in the second aspect of the invention, the driven
roller is free to ascend and descend.
It is a third aspect of the invention to present a focusing
device for film density detector used in a film density detector for
detecting the film density by mounting and conveying a film on the top
of a shell member formed in an arc, scanning the conveyed film surface
with laser beam, and focusing the transmitted light, comprising a box-shaped
main body composed of parallel ceiling member and bottom member
having the longitudinal direction in the scanning direction of laser
beam constituted by combining flat members, and a pair of photo
detecting means disposed at proper positions on planes parallel to the
scanning plane of laser beam of the main body, further forming a ceiling
member contacting with the back side of a shell member on which the
film of the box-shaped main body is mounted and conveyed, along the back
side of the shell member, and forming a slit along the scanning
direction of the laser beam for moving the laser beam forward into the
main body in this ceiling member.
Preferably, in the third aspect of the invention, the slit is
covered with a scattering film for scattering the light appropriately.
Preferably, in the third aspect of the invention, a coating is
formed inside of the box-shaped main body for preventing absorption of
laser beam getting into the main body.
Since the first aspect of the invention is thus constituted,
without using F-Θ lens in the scanning unit, the reading precision of
transmission type film is enhanced.
Since the second aspect of the invention is thus constituted,
the film runs along the arc surface only by mounting the film on the arc
surface. Accordingly, it is not necessary to move the film along the
conveying surface by pressing by the driving roller and driven roller,
so that the constitution of the driving roller and driven roller may be
simplified.
Since the third aspect of the invention is thus constituted, the
film conveyed nearly in an arc form can be kept nearly in tight contact
over the entire width, and the scanning speed of laser beam may be
constant regardless of the focusing device for film concentration
detector, and the reading apparatus of transmission type film on which
it is mounted is not increased in size.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is an essential perspective view of a reading apparatus
of transmission type film of the invention.
Fig. 2 is a lateral sectional view of the reading apparatus.
Fig. 3 is a left side view showing a partial section of the
reading apparatus.
Fig. 4 is a sectional view of a right side leading end portion
of the reading apparatus.
Fig. 5 is a schematic diagram of a film conveying mechanism.
Fig. 6 is an explanatory diagram showing the circumferential
shape of driving wheel and driven wheel.
Fig. 7 is an explanatory diagram of disposing method of driving
wheel and driven wheel, in which the extension line of the central line
of the driving wheel and driven wheel passing through the center of
curvature of the arc table in (a), and it is vertical in (b).
Fig. 8 is a schematic diagram of a link mechanism used in the
reading apparatus.
Fig. 9 is a perspective view of a focusing device for film
density detector used in the reading apparatus.
Fig. 10 is its perspective exploded view.
Fig. 11 is a perspective view showing the focusing device
separated from the arc table.
Fig. 12 is a perspective exploded view of width aligning
mechanism of film.
Fig. 13 is an operation explanatory diagram of a reading
apparatus of the invention, showing an initial state of the reading
apparatus.
Fig. 14 is the operation explanatory diagram, showing a film
inserted state.
Fig. 15 is the operation explanatory diagram, showing a lowered
state of an upper guide.
Fig. 16 is the operation explanatory diagram, showing a state of
the film end being pulled in to a position dislocated from the laser
beam.
Fig. 17 is the operation explanatory diagram, showing a
discharged state of a film being read.
Fig. 18 is an explanatory diagram of an optical system in a
conventional reading apparatus.
Fig. 19 is a schematic diagram of a film conveying device in the
same reading apparatus.
Fig. 20 is a schematic diagram of other example of the
conventional reading apparatus.
Fig. 21 is a schematic diagram of a different example of the
conventional reading apparatus.
BEST MODE FOR CARRYING OUT THE INVENTION
Referring now to the accompanying drawings, embodiments of the
invention are described below, but it must be noted that the invention
is not limited to the illustrated embodiments alone.
A perspective view of essential parts of a reading apparatus of
transmission type film for medical use (hereinafter called reading
apparatus) R in an embodiment of the invention is given in Fig. 1, and a
front sectional view, a left side view, and a partial right side view
of the reading apparatus R are shown in Fig. 2, Fig. 3, and Fig. 4,
respectively. This reading apparatus R comprises, as shown in the
drawings, a scanning unit U, an arc table 10 having an arc surface 11 in
an arc form along the main scanning direction L of a film F, a film
conveying mechanism 20 for sub-scanning of film F mounted on this arc
surface 11, and a focusing device for film density detector (hereinafter
called focusing device) 30, as principal constituent elements.
The scanning unit U is similar to the conventional scanning unit
except that the F-Θ lens is not provided.
The arc table 10 has the arc surface 11 similar to a free
deflection curve of the film F formed when supporting the end of the
film F orthogonal to the main scanning direction L. For example, in a
film F of 14-inch width, the radius of curvature of the arc surface 11
is about 300 mm. By thus forming the arc surface 11, when the film F is
put on the arc table 10, since the film F is naturally fitted to the
arc surface 11, it is possible to equalize the optical path length from
the polygonal mirror (not shown) mounted on the scanning unit U at each
position along the main scanning direction L of the film F surface
without having to press the film F by roller or the like.
The film conveying mechanism 20 is composed of a first drive
unit 21 and a second drive unit 22 disposed across the main scanning
surface S as shown in Fig. 1, and each one of the first drive unit 21
and second drive unit 22 is a combination of a driving roller 23 and a
driven roller 24 similarly composed as shown in Fig. 5. This driving
roller 23 is composed of a pair of driving wheels 23b, 23b in a plate
form disposed at a specific interval on a drive shaft 23a driven, for
example, by a motor through a power transmission mechanism, and the
driven roller 24 is composed of a pair of driven wheels 24b, 24b in a
plate form disposed on a shaft 24a held rotatably on an elevatable
member through proper means corresponding to the driving wheels 23b,
23b. The outer circumferences 23c, 24c of the driving wheel 23 and
driving wheel 24b are arc surfaces as shown in Fig. 6. Since the outer
circumferences 23c, 24c of the driving wheel 23b and driven wheel 24b
are thus formed, useless deformation of the film F when the driving
wheel 23b and driven wheel 24b pinch the film F is prevented.
Thus constituted driving roller 23 is disposed beneath the arc
table 10 so that the outer circumference 23c of the driving wheel 23b
may contact with the back side of the film F, and the driven roller 24
is disposed above the arc table 10 so that the outer circumference 24c
of the driven wheel 24b may contact with the face side of the film F.
Accordingly, at a position corresponding to the arc table 10, as shown
in Fig. 1, a window 12 is provided so that the driving wheel 23b may
project from the surface of the arc surface 11. In this case, as shown
in Fig. 7 (a), it is preferred to dispose so that the extension line of
the central line of the driving wheel 23b and driven wheel 24b may pass
through the center of curvature O of the arc table 10, but when
preferred to avoid complicated structure of drive mechanism, as shown in
Fig. 7 (b), the driving wheel 23b and driven wheel 24b may be disposed
vertically. By such constitution of four-point driving and driven
structure, the film is conveyed stably, preventing meandering and
sliding of film F. A power transmission mechanism 25 for driving the
driving roller 23 is, as shown in Fig. 2 and Fig. 3, composed of a shaft
side transmission member 25a fitted to the end portion of the drive
shafts 23a, 23a, a motor side transmission member 25b fitted to the end
portion of the drive shaft of motor M1, and a belt 25c applied between
the shaft side transmission members 25a, 25a and motor side transmission
member 25b.
An elevatable member holding the driven roller 24 is
specifically an upper guide 26 moved up and down by a link mechanism.
This upper guide 26 comprises, as shown in Fig. 3 to Fig. 5, a first
holder 26a holding the driven roller 24 of the first drive unit 21, a
second holder 26b holding the driven roller 24 of the second drive unit
22, an upper guide main body 26c holding the first holder 26a and second
holder 26b, a link 26d for moving up and down the guide main body 26c,
and a rotary disk 26e, and the upper end of the link 26d is joined by
pin at a proper position of the upper guide main body 26c, and the lower
end is joined by pin at an outer circumference of the rotary disk 26e.
This link 26d is specifically composed of an upper link 26f and a lower
link 26g, and the lower end of the upper link 26f and the upper end of
the lower link 27g are rotatably joined (see Fig. 8). A slot 26h is
formed at the leading end of the upper link 26f, and a pin 26i planted
on the guide main body 26c is slidably engaged with this slot 26h. A
proper position in the center of the upper link 26f is oscillatably
fitted by pin. On the other hand, the lower end of the lower link 26g
is rotatably joined by pin to the rotary disk 26e as mentioned above.
As the upper guide 26 is thus constituted, when the rotary disk
26e is rotated by motor M2, the upper guide main body 26c is moved up or
down, and the first holder 26a and second holder 26b held by it are
also moved up or down. That is, the driven rollers 24, 24 ascend or
descend. Incidentally, the mechanism for moving up and down the driven
rollers 24 is not limited to the above constitution, but other proper
means may be used, and, for example, it may be designed to move up and
down by chain drive.
The focusing device 30 comprises, as shown in Fig. 9 through
Fig. 11, a main body 40, and a photo detector 50 disposed at a proper
position of this main body.
The main body 40 is, as shown in Fig. 10 and Fig. 11, is a box
(focusing box) 40A of rectangular section, with the top 40a formed in an
arc form in a curvature corresponding to the curvature of the arc
surface 11, so as to be mounted on the back side 11a of the arc surface
11a along the width direction of the arc table 10. This box 40A is
formed by assembling, as shown in Fig. 2, a ceiling plate 41 formed in a
curved surface corresponding to the curved surface of the arc surface
11 abutting against the back side 11a of the arc surface 11, a right
side plate 42, a left side plate 43, a front plate 44 having the upper
end formed in an arc along the inner side of the ceiling plate 41, a
rear plate 45 having the upper end formed in an arc along the inner
side, and a bottom plate 46 formed in the curved surface in a concentric
circle with the ceiling plate 41. Herein, the longitudinal direction
is based on the conveying direction of the film F (see arrow in Fig.
11).
These plates 41, 42, 43, 44, 45, 46 are assembled, for example
as shown in Fig. 10, by forming assembly plates 42a, 43a for assembling
the ceiling plate 41 outward to the upper end of the right side plate 42
and left side plate 43 integrally in a proper size, fastening these
assembly plates 42a, 43a formed outward from both ends of the ceiling
plate 41 corresponding to these assembly plates 42a, 43a with screws,
forming assembly plates 42b, 43b for assembling the front plate 44
outward to the front end of the right side plate 42 and left side plate
43 integrally in a proper size, fastening the both ends of the front
plate 44 to the assembly plates 42b, 43b with screws, having the upper
end abutting against the inner side of the ceiling plate 41, forming
assembly plates 42c, 43c for assembling the rear plate 45 outward to the
rear end of the right side plate 42 and left side plate 43 integrally
in a proper size, fastening the both ends of the rear plat 45 to these
assembly plates 42c, 43c with screws, having the upper end abutting
against the inner side of the ceiling plate 41, forming stopping holes
42d, 43d in the bottom of the right side plate 42 and left side plate
43, stopping the stopping protrusions 45a, 45a formed corresponding to
these stopping holes 42d, 43d at the end of the bottom plate 46 in the
stopping holes 42d, 43d disposing an assembly plate 47 having assembly
portions 47a provided downward from the end of the bottom plate 46 at
proper intervals in the front and rear portions of the back side of the
bottom plate 46, and fastening the bottom of the front plate 44 and rear
plate 45 to the assembly portions 47a with screws.
Thus assembled focusing box 40A is assembled in the back side
11a of the laser beam irradiation position from the scanning unit U of
the arc surface 11 of the arc table 10, and light is focused. That is,
the light passing through a slit 13 formed at the laser beam irradiation
position from the scanning unit U of the arc surface 11 penetrates and
invades a slit 41b formed corresponding to the slit 13 in the ceiling
plat 41 in the focusing box 40A, and the laser beam invading into the
focusing box 40A is irregularly reflected repeatedly in the focusing box
40A, and enters a photo detector 50 provided in a pair of mounting
members 48 formed at a proper interval in the rear plat 45, and the
laser beam entering the photo detector 50 is converted into an electric
signal same as in prior art, and is sent out into a density detector
(not shown). The density detector detects, same as in prior art, the
density of the laser beam passing through the film F by the signal
entering from the photo detector 50. The focusing box 40A is assembled
into the arc table 10 by, for example, stopping the screws assembling
the ceiling plate 41 into the side plates 42, 43 into the arc table 10
(see Fig. 11).
In this case, only by properly scattering the laser beam
penetrating the slit 41b formed in the ceiling plate 41, it uniformly
gets into the focusing box 40A, and therefore the position of forming
the slit 41b in the ceiling plate 41 is covered with a scattering film
49. As this scattering film 49, for example. Scotch Mending Tape (a
tradename of Sumitomo-3M) may be used by removing its adhesive.
The inside of the focusing box 40A is coated in order to focus
the laser beam entering the focusing box 40A by decreasing the
absorption in the inside of the focusing box 40A. For this coating, for
example, a water-based acrylic paint and barium sulfate are mixed at 1
to 10 by volume, and dissolved in purified water to prepare a creamy
paint, which is applied in multiple layers. This coating is applied
while properly polishing with sandpaper so as to remove extra
undulations from the surface.
More specifically, the coating procedure is as follows.
(1) The ceiling plate 41, right and left side plates 42, 43,
front plate 44, rear plate 45, and bottom plate 46 are degreased by
cleaning with alcohol. (2) A coating material is prepared. For example, water-based
acrylic paint and barium sulfate are mixed at 1 to 10 by volume, and
dissolved in purified water to prepare like whipped cream. The water-based
acrylic paint used herein is Floor White (a tradename of Nippon
Paint), and barium sulfate is Baritogen Deluxe (a tradename of Fushimi
Seiyakusho). (3) The obtained coating material is sparingly applied on each
inner surface of ceiling plate 41, right and left side plates 42, 43,
front plate 44, rear plate 45, and bottom plate 46. This is so-called
surface conditioning of the inner surfaces of 41, 42, 43, 44, 45, 46. (4) When the surface conditioning agent is dried, an undercoat
is applied. In this case, the thickness of coat film is in a range of 1
mm to 2 mm. (5) When the undercoat is dried, the surface is polished flat
with sandpaper to remove undulations of coat film. (6) After polishing with sandpaper, the focusing box 40A is
assembled in a semi-finished state, except for the ceiling plate 41 and
rear plate 45. (7) In the semi-finished state of the focusing box 40A, a
middle coat is applied. This middle coat is also applied to the ceiling
plate 41 and rear plate 45 which have not been assembled yet. In this
case, the thickness of the coat film is in a range of 2 mm to 3 mm. (8) When the middle coat is dried, the surface is polished flat
with sandpaper to remove undulations of coat film. (9) After polishing with sandpaper, a top coat is applied.
This top coat is also applied to the ceiling plate 41 and rear plate 45
which have not been assembled yet. In this case, the thickness of the
coat film is in a range of 3 mm to 4 mm. (10) When the top coat is dried, the surface is polished flat
with sandpaper to remove undulations of coat film. At this time, the
thickness of coat film is 3 mm or more. (11) The rear plate 45 is assembled in the semi-finished
focusing box 40A. (12) The coating material is applied on the abutting portions
of the plates 42, 43, 44, 45 of the focusing box 40A with the ceiling in
open state. (13) The ceiling plate 41 is assembled to complete the focusing
box 40A.
Fig. 11 and Fig. 12 show a width aligning mechanism 60 for
adjusting the width direction position of the film F used in this
embodiment. The width aligning mechanism 60 comprises a width aligning
member 61, a drive mechanism 62 for driving the width aligning member
61, and a mounting member 63 for mounting the width aligning member 61
on the drive mechanism 62, and a set of confronting width aligning
mechanisms 60 is disposed in the arc table 11 across a specific interval
(see Fig. 11). As thus disposed width aligning members 61 move along
the guide groove 14 provided in the arc surface 11, the film F is
aligned in width.
The drive mechanism 62 specifically comprises a flexible rack 64
made of synthetic resin, and a motor (not shown) having a pinion for
driving the rack 64. The rack 64 is slidably provided in a guide 15
disposed at a proper position of the back side 11a of the arc surface
11.
In Fig. 12, reference numeral 65 is a bolt for rotatably fixing
the width aligning member 61, 66 is a nut to be combined with this bolt,
67 is a bolt for fixing the mounting member 63 to the rack 64, and 68
is a spacer nut to be combined with the bolt 64.
Referring also to Fig. 13 to Fig. 17, reading of the film F by
thus constituted reading apparatus R is described. In the following
operation, each action is instructed by the control device N.
(1) The power source is turned on, and the upper guide 26 is
pulled up to a specified position (see Fig. 13). (2) The film F is manually inserted and set in the reading
apparatus R through the inlet (see Fig. 14). (3) The upper guide 26 is lowered to a specified position, and
the film F is held between the drive rollers 23, 23 and driven rollers
24, 24 (see Fig. 15). (4) Driving the first drive unit 21 and second drive unit 22,
the end of the film F is pulled until dislocated from the laser beam
from the scanning unit U (see Fig. 16). (5) When the film F is conveyed by the first drive unit 21 and
second drive unit 22 and the end of the film F reaches a specified
position, the first drive unit 21 and second drive unit 22 are stopped,
and conveying of the film F is stopped. (6) A laser beam is emitted from the scanning unit U, and scan
(main scanning) is started. (7) When scanning of one line is over, emission of laser beam
from the scanning unit U is stopped, and the first drive unit 21 and
second drive unit 22 are driven again, and the film F is fed by a
specified amount.
Thereafter, the specified range of the film F is scanned
similarly.
Thus, according to the embodiment, although the film conveying
mechanism is simplified, the F-Θ lens in the optical system can be
omitted. Therefore, the cost of the reading apparatus R including the
scanning unit U is lowered. Also according to the embodiment, since the
focusing device 30 is mounted on the back side 11a along the width
direction of the arc surface 11 of the arc table 10, the width of the
focusing device 30 may be a minimum required limit, and the scanning
speed with the laser beam may be constant in the entire irradiation area
so as to be focused by the focusing device 30. As a result, the
precision of concentration detection can enhanced while preventing
useless increase in size of the reading apparatus R. Moreover, since
the focusing box 40A composing the focusing device 30 is formed by
combining flat plates, manufacturing is easy, including coating of
inside.
INDUSTRIAL APPLICABILITY
According to the invention thus described specifically, although
the film conveying mechanism is simplified, the F-Θ lens in the
optical system can be omitted. Therefore, the cost of the reading
apparatus including the scanning unit U is lowered.
Also according to the invention, since the focusing device for
film density detector is mounted on the back side of the arc surface
along the width direction of the arc table of the reading apparatus, the
width of the focusing device for film density detector may be a minimum
required limit, and moreover the scanning speed with the laser beam may
be constant in the entire irradiation area so as to be focused by the
focusing device for film density detector. As a result, the precision
of concentration detection can enhanced while preventing useless
increase in size of the reading apparatus. Still more, since the
focusing box composing the focusing device for film density detector is
formed by combining flat plates, manufacturing is easy, including
coating of inside.